FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Zhang, JZ Ortner, PB AF Zhang, JZ Ortner, PB TI Effect of thawing condition on the recovery of reactive silicic acid from frozen natural water samples SO WATER RESEARCH LA English DT Article DE water samples; frozen storage; silicic acid; thawing condition; recovery ID STORAGE; NITRATE; PHOSPHATE; SEAWATER; QUARTZ AB A method for thawing frozen samples for silicic acid analysis is recommended. The maximum recovery of silicic acid is achieved by thawing the frozen samples in a refrigerator (at 4 degrees C) in the dark for at least four days. This method significantly improves the recovery of silicic acid From frozen fresh water samples. It also permits close to 100% recovery of reactive silicic acid from Frozen seawater samples even after three months storage. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Cooperat Inst Marine & Atmospher Studies, AOML,NOAA, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Cooperat Inst Marine & Atmospher Studies, AOML,NOAA, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Zhang, Jia-Zhong/B-7708-2008 OI Zhang, Jia-Zhong/0000-0002-1138-2556 NR 18 TC 10 Z9 12 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD AUG PY 1998 VL 32 IS 8 BP 2553 EP 2555 DI 10.1016/S0043-1354(98)00005-0 PG 3 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 106QY UT WOS:000075141400032 ER PT J AU Levine, ZH AF Levine, ZH TI Magnetic dichroism at the giant dipole resonance of Fe and Mn via time-dependent density-functional theory SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID X-RAY DICHROISM; CIRCULAR-DICHROISM; OPTICAL-RESPONSE; APPROXIMATION; ATOMS; PROGRAM; SYSTEMS; GD; PHOTOABSORPTION; PHOTOEMISSION AB The polarization-resolved photoabsorption cross section has been calculated in the vicinity of the 3p --> 3d giant dipole resonances of Fe (45-65 eV) and Mn (45-60 eV) using the relativistic time-dependent local spin-density approximation. The method accounts for the largest features in the unpolarized experimental total cross sections, after Gaussian broadening is applied; however, minor features are not given correctly. Both circular and linear dichroic spectra are presented, however experimental data are not yet available. C1 NIST, Gaithersburg, MD 20899 USA. RP Levine, ZH (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 45 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUL 28 PY 1998 VL 31 IS 14 BP 3155 EP 3166 DI 10.1088/0953-4075/31/14/014 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 109ME UT WOS:000075325700014 ER PT J AU Levicky, R Koneripalli, N Tirrell, M Ankner, JF Kaiser, H Satija, SK AF Levicky, R Koneripalli, N Tirrell, M Ankner, JF Kaiser, H Satija, SK TI Selectively swollen films of triblock/diblock copolymer blends: Dependence of swollen film structure on blend composition SO MACROMOLECULES LA English DT Article ID GRAFTED POLYMERIC BRUSHES; TELECHELIC POLYMERS; DIBLOCK COPOLYMERS; LAMELLAR STRUCTURE; GOOD SOLVENT; SURFACE; SCATTERING; CHAINS; BLOCK AB Compositional variation in blends of triblock and diblock copolymer films can be used to adjust the film response to a selective solvent. We investigated the relationship between blend composition and film structure in ordered films containing poly(styrene-b-2-vinylpyridine) (PS-P2VP) diblocks and PS-P2VP-PS triblocks. The study focuses on films possessing a lamellar morphology. Methanol, a strongly selective solvent for P2VP, is used to swell the films. Since methanol solvates P2VP but not PS, periodic multilayer structures result in which solvent-rich P2VP domains are separated by undissolved PS domains. The film structure is characterized in the dry and swollen states with neutron reflectivity. Although the dry state morphology dimensions are practically identical for all samples, in the swollen state films richer in triblock swell less due to higher density of bridges interconnecting the PS domains. Furthermore, in swollen triblock-containing samples, polymer concentration variations in P2VP domains are suppressed and the PS domains are better aligned with respect to the substrate. C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Univ Missouri, Res Reactor, Columbia, MO 65211 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Tirrell, M (reprint author), Univ Minnesota, Dept Chem Engn & Mat Sci, 421 Washington Ave SE, Minneapolis, MN 55455 USA. OI Ankner, John/0000-0002-6737-5718 NR 22 TC 9 Z9 10 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUL 28 PY 1998 VL 31 IS 15 BP 4908 EP 4914 DI 10.1021/ma9716185 PG 7 WC Polymer Science SC Polymer Science GA 106WU UT WOS:000075174800034 ER PT J AU Welp, KA Wool, RP Satija, SK Pispas, S Mays, J AF Welp, KA Wool, RP Satija, SK Pispas, S Mays, J TI Dynamics of polymer interdiffusion: The ripple experiment SO MACROMOLECULES LA English DT Article ID LATERAL DIFFUSION-MODEL; ION MASS-SPECTROSCOPY; TUBE MODEL; CHAIN; INTERFACES; LIQUIDS; MELTS; REPTATION; SYSTEMS; ENTANGLEMENTS AB We explore the interdiffusion of oppositely labeled triblock polystyrene chains, HDH/DHD, during welding in the melt using dynamic secondary ion mass spectroscopy (DSIMS) and specular neutron reflectivity (SNR). The HDH chains have the central portion of the chain deuterated (D) similar to 50% while the two ends (H) each have similar to 25% protonation; the DHD is oppositely labeled, but each set of chains contains about 50% deuteration. During welding, the deuterium depth profile exhibits "ripples" whose characteristic features, such as the time and molecular weight dependent shape, amplitude, and position, are very sensitive to the microscopic details of the polymer dynamics. The ripple experiment is especially sensitive to the presence, or absence, of topological constraints and anisotropic motion of chains. The current work significantly extends the molecular weight range up to 400 000. This allows greater separation of the six key ripple features used in deciphering the correct polymer dynamics model at the polymer-polymer interface. The DSIMS and SNR experimental results are compared to theoretical predictions and ripple simulations for Rouse, polymer mode-coupling, reptation (with and without tube broadening), and other phenomenological dynamics models. The six ripple characteristics were found to be perfectly correlated and convincingly consistent with the predictions of the reptation dynamics model. The ripple results are in significant disagreement with the polymer mode-coupling model proposed by Schweizer and other tubeless models. We conclude that the reptation model, proposed by DeGennes in 1971 with parallel developments by Edwards, is the correct model to describe the dynamics of polymer interdiffusion. C1 Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. Univ Delaware, Ctr Composite Mat, Newark, DE 19716 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Alabama Birmingham, Dept Chem, Birmingham, AL 35294 USA. RP Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. NR 39 TC 29 Z9 29 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD JUL 28 PY 1998 VL 31 IS 15 BP 4915 EP 4925 DI 10.1021/ma971692n PG 11 WC Polymer Science SC Polymer Science GA 106WU UT WOS:000075174800035 ER PT J AU Kishore, N Tewari, YB Akers, DL Goldberg, RN Miles, EW AF Kishore, N Tewari, YB Akers, DL Goldberg, RN Miles, EW TI A thermodynamic investigation of reactions catalyzed by tryptophan synthase SO BIOPHYSICAL CHEMISTRY LA English DT Article DE enthalpy; apparent equilibrium constant; entropy; thermodynamics; tryptophan synthase ID SALMONELLA-TYPHIMURIUM; ESCHERICHIA-COLI; BIOCHEMICAL REACTIONS; AQUEOUS-SOLUTION; HEAT-CAPACITIES; BETA-SUBUNIT; EQUILIBRIUM; COMPLEX; VOLUMES; ALPHA AB Microcalorimetry and high-performance liquid chromatography have been used to conduct a thermodynamic investigation of the following reactions catalyzed by the tryptophan synthase alpha(2) beta(2) complex (EC 4.2.1.20) and its subunits: indole(aq) + L-serine(aq) = L-tryptophan(aq) + H2O(1); L-serine(aq) = pyruvate(aq) + ammonia(aq); indole(aq) + D-glyceraldehyde 3-phosphate(aq) = 1-(indol-3-yl)glycerol 3-phosphate(aq); L-serine(aq) + 1-(indol-3-yl)glycerol 3-phosphate(aq) = L-tryptophan(aq) + D-glyceraldehyde 3-phosphate(aq) + H2O(1). The calorimetric measurements led to standard molar enthalpy changes for all four of these reactions. Direct measurements yielded an apparent equilibrium constant for the third reaction; equilibrium constants for the remaining three reactions were obtained by using thermochemical cycle calculations. The results of the calorimetric and equilibrium measurements were analyzed in terms of a chemical equilibrium model that accounted for the multiplicity of the ionic states of the reactants and products. Thermodynamic quantities for chemical reference reactions involving specific ionic forms have been obtained. These quantities permit the calculation of the position of equilibrium of the above four reactions as a function of temperature, pH, and ionic strength. Values of the apparent equilibrium constants and standard transformed Gibbs free energy changes Delta(r)G'(o)(m) under approximately physiological conditions are given. Le Chatelier's principle provides an explanation as to why, in the metabolic pathway leading to the synthesis of L-tryptophan, the third reaction proceeds in the direction of formation of indole and D-glyceraldehyde 3-phosphate even though the apparent equilibrium constant greatly favors the formation of 1-(indol-3-yl) glycerol 3-phosphate. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NIDDK, Lab Biochem & Genet, NIH, Bethesda, MD 20892 USA. RP Goldberg, RN (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. EM robert.goldberg@nist.gov NR 44 TC 8 Z9 8 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 EI 1873-4200 J9 BIOPHYS CHEM JI Biophys. Chem. PD JUL 27 PY 1998 VL 73 IS 3 BP 265 EP 280 DI 10.1016/S0301-4622(98)00151-3 PG 16 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 104VB UT WOS:000075035600007 PM 9700925 ER PT J AU Coakley, KJ Simons, DS AF Coakley, KJ Simons, DS TI Detection and quantification of isotopic ratio inhomogeneity SO CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS LA English DT Article DE bootstrap resampling; hypothesis testing; inhomogeneity; isotopic ratio; Monte Carlo; Secondary Ion Mass Spectrometry; spatial variation ID BOOTSTRAP AB We quantify the spatial variation of the ratio of two isotopes within a material based on Secondary Ion Mass Spectrometry (SIMS) data. At many spatial locations, a detector counts each of two isotopes of a chemical element. At each location, we predict the less abundant isotope count in terms of the measured value of the more abundant isotope count and the estimated mean isotopic ratio. At each location, the expected value of the prediction error depends on the difference between the actual isotopic ratio at that location, and the estimated spatial mean value of the isotopic ratio. To get weighted residuals, the difference between the measured and the predicted value is divided by an estimate of its root mean square value. To estimate the spatial standard deviation of the isotopic ratio, we equate the sum of the squared weighted residuals to its approximate expected value. The approximate expected value is obtained by a bootstrap resampling method. Based on the estimated null distribution of the estimated spatial standard deviation, we test the hypothesis that the isotopic ratio is constant throughout the sample. To check the validity of our methods, we analyze SIMS data collected from a homogeneous chromium sample. Results are consistent with the hypothesis of homogeneity. We simulate data corresponding to a sample where the isotopic ratio has a binary distribution; when the standard deviation of the binary distribution exceeds twice the 86th percentile of the null distribution, detection of inhomogeneity is almost certain. Further, the expected value of the estimated standard deviation closely tracks the actual standard deviation. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Stat Engn Div, Boulder, CO 80303 USA. NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Coakley, KJ (reprint author), Natl Inst Stand & Technol, Stat Engn Div, 325 Broadway, Boulder, CO 80303 USA. NR 15 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7439 J9 CHEMOMETR INTELL LAB JI Chemometrics Intell. Lab. Syst. PD JUL 27 PY 1998 VL 41 IS 2 BP 209 EP 220 DI 10.1016/S0169-7439(98)00045-8 PG 12 WC Automation & Control Systems; Chemistry, Analytical; Computer Science, Artificial Intelligence; Instruments & Instrumentation; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Automation & Control Systems; Chemistry; Computer Science; Instruments & Instrumentation; Mathematics GA 105RY UT WOS:000075088400006 ER PT J AU Boucher, O Schwartz, SE Ackerman, TP Anderson, TL Bergstrom, B Bonnel, B Chylek, P Dahlback, A Fouquart, Y Fu, Q Halthore, RN Haywood, JM Iversen, T Kato, S Kinne, S Kirkevag, A Knapp, KR Lacis, A Laszlo, I Mishchenko, MI Nemesure, S Ramaswamy, V Roberts, DL Russell, P Schlesinger, ME Stephens, GL Wagener, R Wang, M Wong, J Yang, F AF Boucher, O Schwartz, SE Ackerman, TP Anderson, TL Bergstrom, B Bonnel, B Chylek, P Dahlback, A Fouquart, Y Fu, Q Halthore, RN Haywood, JM Iversen, T Kato, S Kinne, S Kirkevag, A Knapp, KR Lacis, A Laszlo, I Mishchenko, MI Nemesure, S Ramaswamy, V Roberts, DL Russell, P Schlesinger, ME Stephens, GL Wagener, R Wang, M Wong, J Yang, F TI Intercomparison of models representing direct shortwave radiative forcing by sulfate aerosols SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTHROPOGENIC AEROSOLS; MULTIPLE-SCATTERING; SOLAR-RADIATION; CLIMATE MODELS; ATMOSPHERES; ABSORPTION; PARAMETERIZATION; UNCERTAINTY; EXTINCTION; ALGORITHMS AB The importance of aerosols as agents of climate change has recently been highlighted. However, the magnitude of aerosol forcing by scattering of shortwave radiation (direct forcing) is still very uncertain even for the relatively well characterized sulfate aerosol. A potential source of uncertainty is in the model representation of aerosol optical properties and aerosol influences on radiative transfer in the atmosphere. Although radiative transfer methods and codes have been compared in the past, these comparisons have not focused on aerosol forcing (change in net radiative flux at the top of the atmosphere). Here we report results of a project involving 12 groups using 15 models to examine radiative forcing by sulfate aerosol for a wide range of values of particle radius, aerosol optical depth, surface albedo, and solar zenith angle. Among the models that were employed were high and low spectral resolution models incorporating a variety of radiative transfer approximations as well as a line-by-line model. The normalized forcings (forcing per sulfate column burden) obtained with the several radiative transfer models were examined, and the discrepancies were characterized. All models simulate forcings of comparable amplitude and exhibit a similar dependence on input parameters. As expected for a non-light-absorbing aerosol, forcings were negative (cooling influence) except at high surface albedo combined with small solar zenith angle. The relative standard deviation of the zenith-angle-averaged normalized broadband forcing for 15 models was 8% for particle radius near the maximum in this forcing (similar to 0.2 mu m) and at low surface albedo. Somewhat greater model-to-model discrepancies were exhibited at specific solar zenith angles. Still greater discrepancies were exhibited at small particle radii, and much greater discrepancies were exhibited at high surface albedos, at which the forcing changes sign; in these situations, however, the normalized forcing is quite small. Discrepancies among the models arise from inaccuracies in Mie calculations, differing treatment of the angular scattering phase function, differing wavelength and angular resolution, and differing treatment of multiple scattering. These results imply the need for standardized radiative transfer methods tailored to the direct aerosol forcing problem. However, the relatively small spread in these results suggests that the uncertainty in forcing arising from the treatment of radiative forcing of a well-characterized aerosol at well-specified surface albedo is smaller than some of the other sources of uncertainty in estimates of direct forcing by anthropogenic sulfate aerosols and anthropogenic aerosols generally. C1 Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. Ecole Normale Super, CNRS, Meteorol Dynam Lab, Paris, France. Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Dalhousie Univ, Dept Phys, Atmospher Sci Program, Halifax, NS B3H 3J5, Canada. Norwegian Inst Air Res, Kjeller, Norway. Meteorol Off, Hadley Ctr Climate Predict & Res, Bracknell RG12 2SY, Berks, England. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Univ Oslo, Dept Geophys, N-0315 Oslo, Norway. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Brookhaven Natl Lab, Analyt Sci Div, Upton, NY 11973 USA. RP Boucher, O (reprint author), Univ Lille 1, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. EM boucher@loa.univ-lille1.fr; ses@bnl.gov; ackerman@essc.psu.edu; tadand@atmos.washington.edu; bergstro@sky.arc.nasa.gov; bonnel@loa.univ.lille1.fr; chylek@atm.dal.ca; arne.dahlback@fys.uio.no; fouquart@loa.univ-lille1.fr; qfu@atm.dal.ca; halthore@bnl.gov; jmhaywood@meto.gov.uk; trond.iversen@geofysikk.uio.no; kato@aerosol.larc.nasa.gov; kinne@spamer.gsfc.nasa.gov; alf.kirkevag@geofysikk.uio.no; knapp@cira.colostate.edu; alacis@giss.nasa.gov; laszlo@atmos.umd.edu; mmishchenko@giss.nasa.gov; nemesure@bnl.gov; vr@gfdl.gov; dlroberts@meto.gov.uk; prussell@mail.arc.nasa.gov; schlesin@atmos.uiuc.edu; stephens@langley.atmos.colostate.edu; wagener@bnl.gov; muyin@atm.dal.ca; jwong@atm.dal.ca; fanglin@atmos.uiuc.edu RI Wagener, Richard/B-5445-2008; Laszlo, Istvan/F-5603-2010; Knapp, Kenneth/E-9817-2011; Lacis, Andrew/D-4658-2012; Boucher, Olivier/J-5810-2012; Boucher, Olivier/K-7483-2012; Schwartz, Stephen/C-2729-2008; Wang, Muyin/K-4006-2014; Mishchenko, Michael/D-4426-2012 OI Wagener, Richard/0000-0003-3892-1182; Laszlo, Istvan/0000-0002-5747-9708; Boucher, Olivier/0000-0003-2328-5769; Boucher, Olivier/0000-0003-2328-5769; Schwartz, Stephen/0000-0001-6288-310X; NR 66 TC 102 Z9 102 U1 3 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1998 VL 103 IS D14 BP 16979 EP 16998 DI 10.1029/98JD00997 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 104BK UT WOS:000074992200008 ER PT J AU Haywood, JM Schwarzkopf, MD Ramaswamy, V AF Haywood, JM Schwarzkopf, MD Ramaswamy, V TI Estimates of radiative forcing due to modeled increases in tropospheric ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFATE AEROSOLS; GREENHOUSE GASES; CLIMATE AB The GFDL R30 general circulation model (GCM) and a fixed dynamical heating model (FDHM) are used to assess the instantaneous and adjusted radiative forcing due to changes in tropospheric ozone caused by anthropogenic activity. Ozone perturbations from the GFDL global chemical transport model are applied to the GCM, and the instantaneous solar and terrestrial radiative forcings are calculated excluding and including clouds. The FDHM is used to calculate the adjusted radiative forcing at the tropopause. The net global annual mean adjusted radiative forcing, including clouds, ranges from +0.29 to +0.35 W m(-2) with similar to 80% of this forcing being in the terrestrial spectrum. If stratospheric adjustment is ignored, the forcing increases by similar to 10%, and if clouds are ignored, the radiative forcing increases by a further 20-30%. These results are in reasonable agreement with earlier studies and suggest that changes in tropospheric ozone due to anthropogenic emissions exert a global mean radiative forcing that is of similar magnitude but of opposite sign to the direct forcing of sulfate aerosols. C1 Princeton Univ, AOS Program, Princeton, NJ 08544 USA. Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Haywood, JM (reprint author), DERA, Meteorol Res Flight, Y46 Bldg, Farnborough GU14 0LX, Hants, England. EM jmhaywood@meto.gov.uk NR 32 TC 34 Z9 35 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1998 VL 103 IS D14 BP 16999 EP 17007 DI 10.1029/98JD01348 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 104BK UT WOS:000074992200009 ER PT J AU Soden, BJ AF Soden, BJ TI Tracking upper tropospheric water vapor radiances: A satellite perspective SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC CONVERGENCE ZONE; RELATIVE-HUMIDITY; IMAGE DATA; TEMPERATURE; MAINTENANCE; CLIMATOLOGY; GREENHOUSE; CHANNEL; LAYER; FIELD AB Hourly observations of 6.7 mu m "water vapor" radiances from geostationary satellites are used in conjunction with an objective pattern-tracking algorithm to trace upper tropospheric water vapor features from sequential images. Analysis of measurements covering the 3 month period of June-August 1987 illustrates a close relationship between the upper tropospheric moisture and the tropical circulation. Over humid tropical regions the movement of water vapor patterns reveals a diverging upper,level flow away from centers of deep convection. Likewise, arid subtropical regions are characterized by converging upper level water vapor patterns indicating sinking air. The evolution of upper tropospheric moisture is also explored from a Lagrangian perspective by considering the change in moisture of a pattern as it is tracked from one image to the next. This analysis reveals that the clear-sky upper troposphere in both tropical and subtropical regions becomes increasingly drier with time reflecting the impact of large-scale subsidence in drying the troposphere; When separated according to cloud amount, water vapor patterns associated with clouds are observed to dry substantially slower than those without clouds, presumably due to the evaporation of cloud condensate. Trajectories of upper tropospheric moisture are also constructed by iteratively tracking water vapor patterns from successive satellite images. The trajectories reveal two distinct paths for water vapor patterns entering the dry subsidence region of the subtropical South Pacific. One path highlights the southward propagation of convective outflow from the tropics while the other path reflects the injection of moisture from eastward propagating subtropical disturbances. The existence of two distinct source regions suggests that a complete picture of the processes regulating the driest and most radiatively transparent regions of the subtropics will require an understanding of both types of convective systems. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Soden, BJ (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308,Forrestal Campus, Princeton, NJ 08542 USA. EM bjs@gfdl.gov NR 34 TC 43 Z9 43 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1998 VL 103 IS D14 BP 17069 EP 17081 DI 10.1029/98JD01151 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 104BK UT WOS:000074992200014 ER PT J AU Wenny, BN Schafer, JS DeLuisi, JJ Saxena, VK Barnard, WF Petropavlovskikh, IV Vergamini, AJ AF Wenny, BN Schafer, JS DeLuisi, JJ Saxena, VK Barnard, WF Petropavlovskikh, IV Vergamini, AJ TI A study of regional aerosol radiative properties and effects on ultraviolet-B radiation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTHROPOGENIC AEROSOLS; SIZE DISTRIBUTIONS; OPTICAL-PROPERTIES; LIGHT-SCATTERING; REFRACTIVE-INDEX; ATLANTIC-OCEAN; UNITED-STATES; IRRADIANCE; UV; OZONE AB A field experiment was conducted in western North Carolina to investigate the relationship between aerosol optical properties and atmospheric transmission. Two research measurement sites in close horizontal proximity but at different altitudes were established to measure the transmission of UV radiation through a slab of atmosphere. An identical set of radiation sensing instruments, including a broadband UV-B radiometer, a direct Sun pyrheliometer, a shadowband radiometer, and a spectral photometer, was placed at both sites, a mountaintop site (Mount Gibbes 35.78 degrees N, 82.29 degrees W, 2004 m elevation) and a valley site;(Black Mountain, North Carolina 35.66 degrees N, 82.38 degrees N, 951 m elevation). Aerosol size distribution sampling equipment was located at the valley site. Broadband solar pseudo-optical depth and aerosol optical depths at 415 nm, 500 nm, and 673 nm were measured for the lowest 1-km layer of the troposphere. The measurements exhibited variations based on an air mass source region as determined by back trajectory analysis. Broadband UV-B transmission through the layer also displayed variations relating to air mass source region. Spectral UV transmission revealed a dependence upon wavelength, with decreased transmission in the UV-B region (300-320 mm) versus UV-A region (320-363.5 mm). UV-B transmission was found to be negatively correlated with aerosol optical depth. Empirical relations were developed to allow prediction of solar noon UV-B transmission if aerosol optical depth at two visible wavelengths (415 and 500 nm) is known. A new method was developed for determining aerosol optical properties from the radiation and aerosol size distribution measurements. The aerosol albedo of single scatter was found to range from 0.75 to 0.93 and the asymmetry factor ranged from 0.63 to 0.76 at 312 nm, which is close to the peak response of human skin to UV radiation. C1 N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. NASA, Hughes STX Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Surface Radiat Res Branch, Boulder, CO 80303 USA. US EPA, Atmospher Res & Exposure Assessment Lab, Res Triangle Pk, NC 27111 USA. Univ Colorado, CIRES, Boulder, CO 80303 USA. Harris Corp, Elect Syst Sector, Palm Bay, FL 32935 USA. RP Saxena, VK (reprint author), N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Box 8208, Raleigh, NC 27695 USA. EM saxena@eos.ncsu.edu RI Schafer, Joel/A-3978-2010 NR 61 TC 48 Z9 48 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1998 VL 103 IS D14 BP 17083 EP 17097 DI 10.1029/98JD01481 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 104BK UT WOS:000074992200015 ER PT J AU Weatherhead, EC Reinsel, GC Tiao, GC Meng, XL Choi, DS Cheang, WK Keller, T DeLuisi, J Wuebbles, DJ Kerr, JB Miller, AJ Oltmans, SJ Frederick, JE AF Weatherhead, EC Reinsel, GC Tiao, GC Meng, XL Choi, DS Cheang, WK Keller, T DeLuisi, J Wuebbles, DJ Kerr, JB Miller, AJ Oltmans, SJ Frederick, JE TI Factors affecting the detection of trends: Statistical considerations and applications to environmental data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE AB Detection of long-term, linear trends is affected by a number of factors, including the size of trend to be detected, the time span of available data, and the magnitude of variability and autocorrelation of the noise in the data. The number of years of data necessary to detect a trend is strongly dependent on, and increases with; the magnitude of variance (sigma(N)(2)) and autocorrelation coefficient (phi) of the noise. For a typical range of values of sigma(N)(2) and phi the number of years of data needed to detect a trend of 5%/decade can vary from similar to 10 to >20 years, implying that in choosing sites to detect trends some locations are likely to be more efficient and cost-effective than others. Additionally, some environmental variables allow for an earlier detection of trends than other variables because of their low variability and autocorrelation. The detection of trends can be confounded when sudden changes occur in the data, such as when an instrument is changed or a volcano erupts. Sudden level shifts in data sets, whether due to artificial sources, such as changes in instrumentation or site location, or natural sources, such as volcanic eruptions or local changes to the environment, can strongly impact the number of years necessary to detect a given trend; increasing the number of years by as much as 50% or more. This paper provides formulae for estimating the number of years necessary to detect trends, along with the estimates of the impact of interventions on trend detection. The uncertainty associated with these estimates is also explored. The results presented are relevant for a variety of practical decisions in managing a monitoring station, such as whether to move an instrument, change monitoring protocols in the middle of a long-term monitoring program, or try to reduce uncertainty in the measurements by improved calibration techniques. The results are also useful for establishing reasonable expectations for trend detection and can be helpful in selecting sites and environmental variables for the detection of trends. An important implication of these results is that it will take several decades of high-quality data to detect the trends likely to occur in nature. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Wisconsin, Dept Stat, Madison, WI 53706 USA. Univ Chicago, Grad Sch Business, Chicago, IL 60637 USA. Univ Chicago, Dept Stat, Chicago, IL 60637 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Air Resources Lab, Boulder, CO 80303 USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Atmospher Environm Serv, Downsview, ON, Canada. NOAA, Natl Weather Serv, Washington, DC 20233 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. RP Weatherhead, EC (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, 325 Broadway, Boulder, CO 80309 USA. EM betsy@srrb.noaa.gov RI Weatherhead, Elizabeth/I-7091-2015 OI Weatherhead, Elizabeth/0000-0002-9252-4228 NR 13 TC 336 Z9 343 U1 5 U2 44 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 1998 VL 103 IS D14 BP 17149 EP 17161 DI 10.1029/98JD00995 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 104BK UT WOS:000074992200019 ER PT J AU Bodeker, P Hucht, A Schreyer, A Borchers, J Guthoff, F Zabel, H AF Bodeker, P Hucht, A Schreyer, A Borchers, J Guthoff, F Zabel, H TI Reorientation of spin density waves in Cr(001) films induced by Fe(001) cap layers SO PHYSICAL REVIEW LETTERS LA English DT Article ID METAL SUPER-LATTICES; INTERLAYER EXCHANGE; CR; ANTIFERROMAGNETISM; MAGNETORESISTANCE; SUPERLATTICES; MULTILAYERS; CHROMIUM; FE AB Proximity effects of 20 Angstrom Fe layers on the spin density waves (SDWs) in epitaxial Cr(001) films are revealed by neutron scattering. Unlike in bulk Cr we observe a SDW with its wave vector Q pointing along only one (100) direction which depends dramatically on the film thickness t(Cr). For t(Cr) < 250 Angstrom the SDW propagates out of plane with the spins in the film plane. For t(Cr) > 1000 Angstrom the SDW propagates in the film plane with the spins out of plane perpendicular to the in-plane Fe moments. This reorientation transition is explained by frustration effects in the antiferromagnetic interaction between Fe and Cr across the Fe/Cr interface due to steps at the interface. C1 Ruhr Univ Bochum, Inst Expt Phys Festkorperphys, D-44780 Bochum, Germany. Univ Duisburg Gesamthsch, D-47048 Duisburg, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Forschungszentrum Julich, D-52425 Julich, Germany. RP Bodeker, P (reprint author), Ruhr Univ Bochum, Inst Expt Phys Festkorperphys, D-44780 Bochum, Germany. RI Hucht, Alfred/H-3181-2011; Zabel, Hartmut/C-1994-2009 OI Hucht, Alfred/0000-0002-9276-0159; NR 22 TC 48 Z9 48 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 27 PY 1998 VL 81 IS 4 BP 914 EP 917 DI 10.1103/PhysRevLett.81.914 PG 4 WC Physics, Multidisciplinary SC Physics GA 105CP UT WOS:000075055100045 ER PT J AU Beaver, B Teng, Y Guiriec, P Hapiot, P Neta, P AF Beaver, B Teng, Y Guiriec, P Hapiot, P Neta, P TI Mechanisms of oxidation of 1,2,5-trimethylpyrrole: Kinetic, spectroscopic, and electrochemical studies SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ELECTRON-SPIN RESONANCE; RADICAL CATIONS; CHLORINE ATOMS; NITROGEN-HETEROCYCLES; CYCLIC VOLTAMMETRY; RATE CONSTANTS; PYRROLE; 2,5-DIMETHYLPYRROLE; SPECTRA; POLYTHIOPHENE AB The oxidation of 1,2,5-trimethylpyrrole (TMP) in aqueous and organic solvents is studied by various techniques. Heating oxygenated chlorobenzene solutions of TMP results in autoxidation that is initiated via reaction of TMP with O-2 and partly propagated via oxidation of TMP by a TMP-derived peroxyl radical. In radiolytic experiments, TMP is oxidized rapidly by Br2(.-) (k = 2.3 x 10(9) L mol(-1) s(-1)), I-2(.-) (k = 5.1 x 10(8) L mol(-1) s(-1)), CCl3O2. (k = 5 x 10(8) L mol(-1) s(-1)), and N-3(.) radicals in aqueous solutions and by peroxyl radicals in organic solvents. One-electron oxidation forms the radical cation, which exhibits significant absorption in the UV (lambda(max) similar to 270 nm, epsilon similar to 1300 L mol(-1) cm(-1)) and weaker absorptions in the visible range. This species undergoes rapid dimerization (2k similar to 5 x 10(8) L mol(-1) s(-1)), and the dimer is very easily oxidized to a stable product absorbing around 460 nm. NMR analysis of the product formed in irradiated CH2Cl2 solutions is in accord with a dication of dimeric TMP. Other products are also formed under different conditions, probably resulting from addition of peroxyl radicals to the pyrrole ring. In cyclic voltammetry experiments at low scan rates, an irreversible peak at a potential of 0.72 V vs SCE is found for oxidation of TMP in acetonitrile solutions, and a stable product absorbing at 460 nm is formed. The formation of this product involves the transfer of more than one electron per TMP monomer. At very high scan rates, a reversible oxidation step is observed, from which a redox potential of 0.87 V vs SCE is derived for the couple TMP/TMP.+. Several mechanisms are suggested for the consumption of O-2 by TMP in organic solvents, including electron transfer and sigma-bonding via peroxyl radical addition. C1 Duquesne Univ, Dept Chem & Biochem, Pittsburgh, PA 15282 USA. Univ Paris 07, CNRS, UMR 7591, Electrochim Mol Lab, F-75251 Paris 05, France. Natl Inst Stand & Technol, Div Phys & Chem Properties, Gaithersburg, MD 20899 USA. RP Neta, P (reprint author), Duquesne Univ, Dept Chem & Biochem, Pittsburgh, PA 15282 USA. NR 47 TC 13 Z9 13 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 23 PY 1998 VL 102 IS 30 BP 6121 EP 6128 DI 10.1021/jp9808328 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 110DF UT WOS:000075364300009 ER PT J AU Sanov, A Nandi, S Jordan, KD Lineberger, WC AF Sanov, A Nandi, S Jordan, KD Lineberger, WC TI Photochemistry of (OCS)(n)(-) cluster ions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CARBON-DIOXIDE CLUSTERS; RARE-GAS ATOMS; ELECTRON-ATTACHMENT; RYDBERG ATOMS; PHOTODISSOCIATION; DISTRIBUTIONS; COLLISION; DYNAMICS; STATES; CS2 AB We report the photochemistry of (OCS)(n)(-) cluster ions following 395 nm (n=2-28) and 790 nm (n=2-4) excitation. In marked contrast to (CO2)(n)(-) extensive bond breaking and rearrangement is observed. Three types of ionic products are identified: S-2(-)(OCS)(k), S-(OCS)(k) /OCS2-(OCS)(k-1), and (OCS)(k)(-). For n<16, 395 nm dissociation is dominated by St-based fragments, supporting the theoretical prediction of a cluster core with a C-2 nu (OCS)(2)(-) dimer structure and covalent C-C and S-S bonds. A shift in the branching ratio in favor of S--based products is observed near n = 16, consistent with an opening of the photodissociation pathway of OCS- core-based clusters. These monomer-based cluster ions may coexist with the dimer-based clusters over a range of n, but electron detachment completely dominates photodissociation as long as their vertical electron detachment energy, increasing with addition of each solvent molecule, is less then the photon energy. An (OCS)(2)(-) conformer of C-2 symmetry With a covalent C-C bond is believed to be responsible for 790 nm dissociation of (OCS)(2)(-) yielding primarily OCS- products. The yield of OCS-, and thus the importance of the C-2 form of (OCS)(2)(-) cluster core, decreases with ncreasing n, perhaps due to more favorable solvation of the C-2 nu form of (OCS)(2)(-) and/or a solvent-induced increase in the rate of interconversion of conformers. The (OCS)(k)(-) products observed in 395 nm photodissociation of the larger (n greater than or equal to 7) clusters are attributed to photofragment caging. Formation and dissociation mechanisms of clusters with different core types are discussed. The photochemical properties of (OCS)(n)(-) are compared to those of the isovalent (CO2)(n)(-) and (CS2)(n)(-) species. (C) 1998 American Institute of Physics. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA. RP Sanov, A (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 30 TC 29 Z9 29 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 22 PY 1998 VL 109 IS 4 BP 1264 EP 1270 DI 10.1063/1.476677 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FP UT WOS:000075255600009 ER PT J AU Meot-Ner, M Scheiner, S Yu, WO AF Meot-Ner, M Scheiner, S Yu, WO TI Ionic hydrogen bonds in bioenergetics. 3. Proton transport in membranes, modeled by ketone/water clusters SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON CORRELATION; CROWN ETHERS; EQUILIBRIA; SOLVATION; TRANSFERS; WATER; MOLECULES; PERMEATION; MECHANISMS; AFFINITIES AB Hydrogen bond networks in protonated acetone/water clusters are stabilized by H(3)O(+)(Me(2)CO)(2) centers, and the stabilizaton increases with further acetone content. For example, proton transfer from neat water (H(2)O)(6)H(+) clusters to form mixed (Me(2)CO)(3)(H(2)O)(3)H(+) clusters is exothermic by 80 kJ/mol(19 kcal/mol), due to strong hydrogen bonding of the carbonyl groups; in a series of mixed clusters B(3)(H(2)O)(3)H(+), the stability of the hydrogen bond network correlates with the proton affinities PA(B). In diketone models of adjacent peptide links, the proton is stabilized by internal hydrogen bonds between the carbonyl groups. The internal bonds can be significant, for example, 31 kJ/mol (7 kcal/mol) in (MeCOCH(2)CH(2)COMe)H(+); but proton transfer through the internal bond has a high barrier. However, water molecules can bridge between the CO groups. In these bridges, the proton remains on an H(3)O(+) center, in both acetone/water and diketone/water systems. With a further H(2)O molecule, the diketone/water cluster (MeCOCH(2)CH(2)COMe)(H(2)O)(2)H(+) and diamide/water clusters form two-water H(3)O(+)...H(2)O bridges, which allow proton transfer between the CO groups with a small barrier of <12 kJ/mol (<3 kcal/mol). The cluster models suggest several roles for hydrogen bonds in proton transport through membranes. (1)Ionic hydrogen bonds involving polar amide groups stabilize ions by up to 135 kJ/mol (32 kcal/mol) in clusters and can similarly stabilize ions in membrane water chains and enzyme centers. (2) The proton can remain on an H(3)O(+) center and, therefore, remain delocalized and mobile in water chains, despite the stronger basicities of the surrounding amide groups. This effect results from electrostatic balancing of opposing peptide amide dipoles. (3) In the water chains, H(3)O(+)...H(2)O bridges between peptide amide groups can provide low-energy pathways for proton transport. C1 Univ Canterbury, Dept Chem, Christchurch 8001, New Zealand. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. So Illinois Univ, Dept Chem, Carbondale, IL 62901 USA. So Illinois Univ, Dept Biochem, Carbondale, IL 62901 USA. RP Meot-Ner, M (reprint author), Univ Canterbury, Dept Chem, Christchurch 8001, New Zealand. NR 47 TC 25 Z9 25 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUL 22 PY 1998 VL 120 IS 28 BP 6980 EP 6990 DI 10.1021/ja971663s PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 104MY UT WOS:000075019400013 ER PT J AU Heiney, PA Gidalevitz, D Maliszewskyj, NC Satija, S Vaknin, D Pan, Y Ford, WT AF Heiney, PA Gidalevitz, D Maliszewskyj, NC Satija, S Vaknin, D Pan, Y Ford, WT TI Multilayer formation in an azacrown [18]N-6 Langmuir film SO CHEMICAL COMMUNICATIONS LA English DT Article ID AIR-WATER-INTERFACE; SELF-ORGANIZATION; MOLECULES; MONOLAYERS AB A neutron reflectivity study of a deuterated azacrown [18]N-6 at the air-water interface shows that it forms multilayers upon compression, with monolayers and trilayers being more stable than bilayers. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Oklahoma State Univ, Dept Chem, Stillwater, OK 74078 USA. RP Heiney, PA (reprint author), Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. RI Gidalevitz, David/D-6717-2012; Vaknin, David/B-3302-2009 OI Vaknin, David/0000-0002-0899-9248 NR 10 TC 2 Z9 2 U1 1 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 1359-7345 J9 CHEM COMMUN JI Chem. Commun. PD JUL 21 PY 1998 IS 14 BP 1483 EP 1484 DI 10.1039/a800388b PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 102JT UT WOS:000074921600031 ER PT J AU Mountain, RD Thirumalai, D AF Mountain, RD Thirumalai, D TI Hydration for a series of hydrocarbons SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; HYDROPHOBIC HYDRATION; COMPUTER-SIMULATION; LIQUID WATER; FORCES; MODEL; PAIR AB The hydrophobic hydration in a series of hydrocarbons is probed by using molecular dynamics simulations. The solutes considered range from methane to octane. Examination of the shapes of the hydration shell suggests that there is no single stable structure surrounding these solutes. The structure of the water molecules around the solute is not significantly perturbed, even for octane, and the hydrogen bond network is essentially preserved. The solutes are accommodated in the voids of the tetrahedral network of water in such a way as to leave the local environment almost intact. The hydrophobic hydration arises primarily because of the plasticity of the hydrogen bond network Even for octane we find very little evidence for water-mediated interactions between nonbonded carbon atoms, leading us to suggest that the transition to globular conformations can only occur for very long, linear hydrocarbon chains. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Univ Maryland, Inst Phys Sci & Technol, Dept Chem & Biochem, College Pk, MD 20742 USA. RP Mountain, RD (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 26 TC 52 Z9 52 U1 0 U2 5 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JUL 21 PY 1998 VL 95 IS 15 BP 8436 EP 8440 DI 10.1073/pnas.95.15.8436 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 103EA UT WOS:000075143900006 PM 9671695 ER PT J AU Messenger, S Amari, S Gao, X Walker, RM Clemett, SJ Chillier, XDF Zare, RN Lewis, RS AF Messenger, S Amari, S Gao, X Walker, RM Clemett, SJ Chillier, XDF Zare, RN Lewis, RS TI Indigenous polycyclic aromatic hydrocarbons in circumstellar graphite grains from primitive meteorites SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; ISM : molecules; molecular processes; stars : carbon ID LASER MASS-SPECTROMETRY; INTERSTELLAR GRAINS; MURCHISON METEORITE; ORDINARY CHONDRITE; EMISSION FEATURES; ORGANIC-ANALYSIS; IDENTIFICATION; MOLECULES; DIAMOND; RATIO AB We report the measurement of polycyclic aromatic hydrocarbons (PAHs) in individual circumstellar graphite grains extracted from two primitive meteorites, Murchison and Acfer 094. The C-12/C-13 isotope ratios of the grains in this study range from 2.4 to 1700. Roughly 70% of the grains have an appreciable concentration of PAHs (500-5000 parts per million [ppm]). Independent molecule-specific isotopic analyses show that most of the PAHs appear isotopically normal, but in several cases correlated isotopic anomalies are observed between one or more molecules and their parent grains. These correlations are most evident for C-13-depleted grains. Possible origins of the PAHs in the graphite grains are discussed. C1 Washington Univ, McDonnell Ctr Space Sci, St Louis, MO 63130 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RP Messenger, S (reprint author), Natl Inst Stand & Technol, Bldg 222,Room A113, Gaithersburg, MD 20899 USA. RI Zare, Richard/A-8410-2009 NR 51 TC 46 Z9 46 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 1998 VL 502 IS 1 BP 284 EP 295 DI 10.1086/305874 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 151WH UT WOS:000077743300025 ER PT J AU Rudich, Y Talukdar, RK Ravishankara, AR AF Rudich, Y Talukdar, RK Ravishankara, AR TI Multiphase chemistry of NO3 in the remote troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; SEA-SALT AEROSOL; GAS-EXCHANGE; NIGHTTIME CHEMISTRY; AQUEOUS-SOLUTIONS; HYPOBROMOUS ACID; REDOX KINETICS; CLOUD; ATLANTIC; SULFUR AB The effect ofNO(3) uptake at night into marine aerosol and cloud droplets on (1) sulfur oxidation, (2) NO3 ambient concentrations, and (3) NO3 atmospheric lifetime is examined using a simple chemical kinetics model. It is shown that the atmospheric lifetime toward multiphase removal of NO3 is < 10 min in presence of cloud droplets. We also show that at low mixing ratios of H2O2 (<150 pmol/mol), NO3 can enhance sulfur oxidation in clouds via a catalytic cycle with a chain length of similar to 8. Finally, in presence of sea-salt aerosol, the uptake of NO, leads to low ambient concentrations of NO3, efficient S(IV) oxidation, and possibly, to release of halogens from the aerosol. The results of this study imply that the multiphase reaction of NO3 may be important in the remote marine boundary layer. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Rudich, Y (reprint author), Weizmann Inst Sci, Dept Environm Sci, IL-76100 Rehovot, Israel. EM yinon@wis.weizmann.ac.il; talukdar@al.noaa.gov RI Rudich, Yinon/K-1498-2012; TALUKDAR, RANAJIT/G-4530-2013; Ravishankara, Akkihebbal/A-2914-2011; OI TALUKDAR, RANAJIT/0000-0001-6017-8431; Rudich, Yinon/0000-0003-3149-0201 NR 58 TC 26 Z9 26 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16133 EP 16143 DI 10.1029/98JD01280 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200013 ER PT J AU Bates, TS Huebert, BJ Gras, JL Griffiths, FB Durkee, PA AF Bates, TS Huebert, BJ Gras, JL Griffiths, FB Durkee, PA TI International Global Atmospheric Chemistry (IGAC) project's first aerosol characterization experiment (ACE 1): Overview SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; TROPOSPHERIC SULFUR CYCLE; DIMETHYL SULFIDE; PARTICLE-SIZE; ANTHROPOGENIC AEROSOLS; GREENHOUSE GASES; CUMULUS CLOUDS; CAPE-GRIM; CLIMATE; SULFATE AB The southern hemisphere marine Aerosol Characterization Experiment (ACE 1) was the first of a series of experiments that will quantify the chemical and physical processes controlling the evolution and properties of the atmospheric aerosol relevant to radiative forcing and climate. The goals of this series of process studies are to reduce the overall uncertainty in the calculation of climate forcing by aerosols and to understand the multiphase atmospheric chemical system sufficiently to be able to provide a prognostic analysis of future radiative forcing and climate response. ACE 1, which was conducted from November 15 to December 14, 1995, over the southwest Pacific Ocean, south of Australia, quantified the chemical, physical, radiative, and cloud nucleating properties and furthered our understanding of the processes controlling the aerosol properties in this minimally polluted marine atmosphere. The experiment involved the efforts of scientists from 45 research institutes in 11 countries. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Hawaii Manoa, Dept Oceanog, Honolulu, HI 96822 USA. CSIRO, Div Atmospher Res, Mordialloc, Vic 3195, Australia. CSIRO, Div Marine Res, Hobart, Tas 7000, Australia. USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. RP Bates, TS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM bates@pmel.noaa.gov RI Bates, Timothy/L-6080-2016 NR 52 TC 229 Z9 235 U1 5 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16297 EP 16318 DI 10.1029/97JD03741 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200026 ER PT J AU Bates, TS Kapustin, VN Quinn, PK Covert, DS Coffman, DJ Mari, C Durkee, PA De Bruyn, WJ Saltzman, ES AF Bates, TS Kapustin, VN Quinn, PK Covert, DS Coffman, DJ Mari, C Durkee, PA De Bruyn, WJ Saltzman, ES TI Processes controlling the distribution of aerosol particles in the lower marine boundary layer during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLOUD CONDENSATION NUCLEI; SIZE DISTRIBUTIONS; METEOROLOGICAL TRANSPORT; OPTICAL-PROPERTIES; NORTHEAST PACIFIC; OZONE OXIDATION; SULFUR-DIOXIDE; MID-PACIFIC; DIMETHYLSULFIDE; NUCLEATION AB The goals of the International Global Atmospheric Chemistry (IGAC) Program's First Aerosol Characterization Experiment (ACE 1) are to determine and understand the properties and controlling factors of the aerosol in the remote marine atmosphere that are relevant to radiative forcing and climate. A key question in terms of this goal and the overall biogeochemical sulfur cycle is what factors control the formation, growth, and evolution of particles in the marine boundary layer (MBL). To address this question, simultaneous measurements of dimethylsulfide (DMS), sulfur dioxide (SO2), the aerosol chemical mass size distribution, and the aerosol number size distribution from 5 to 10,000 nm diameter were made on the National Oceanic and Atmospheric Administration (NOAA) ship Discoverer. From these data we conclude that the background MBL aerosol during ACE 1 often was composed of four distinct modes: an ultrafine (UF) mode (Dp = 5-20 nm), an Aitken mode (Dp = 20-80 nm),an accumulation mode (Dp = 80-300 nm), and a coarse mode (Dp > 300 nm). The presence of UF mode particles in the MBL could be explained by convective mixing between the free troposphere (FT) and the MBL associated with cloud pumping and subsidence following cold frontal passages. There was no evidence of major new particle production in the MBL. Oceanic emissions of DMS appeared to contribute to the growth of Aitken and accumulation mode particles. Coarse mode particles were comprised primarily of sea salt. Although these particles result from turbulence at the air-sea interface, the instantaneous wind speed accounted for only one third of the variance in the coarse mode number concentration in this region. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. Univ Miami, RSMAS, Miami, FL 33124 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Toulouse 3, Lab Aerol, UMR, F-31062 Toulouse, France. USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. RP Bates, TS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM bates@pmel.noaa.gov; kapustin@soest.hawaii.edu; quinn@pmel.noaa.gov; covert@u.washington.edu; derek@pmel.noaa.gov; marc@aero.obs-mp.fr; durkee@nps.navy.mil; debruyn@rsmas.miami.edu; esaltzman@rsmas.miami.edu RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 58 TC 106 Z9 107 U1 5 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16369 EP 16383 DI 10.1029/97JD03720 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200030 ER PT J AU Russell, LM Lenschow, DH Laursen, KK Krummel, PB Siems, ST Bandy, AR Thornton, DC Bates, TS AF Russell, LM Lenschow, DH Laursen, KK Krummel, PB Siems, ST Bandy, AR Thornton, DC Bates, TS TI Bidirectional mixing in an ACE 1 marine boundary layer overlain by a second turbulent layer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB In the Lagrangian B flights of the First Aerosol Characterization Experiment (ACE 1), the chemistry and dynamics of the postfrontal air mass were characterized by tracking a constant-level balloon launched into the air mass for three consecutive 8-hour flights of the instrumented National Center for Atmospheric Research C-130 aircraft during a 33-hour period. The boundary layer extended to a height of 400 to 700 m during this period, with its top;defined by changes in the amount of turbulent mixing measured rather than by an inversion. Above the planetary boundary layer to a height of 1400 to 1900 m, a second layer was capped with a more pronounced temperature inversion and contained only intermittent turbulence. Since this layer served as a reservoir and mixing zone for boundary layer and free tropospheric air, we have called it a buffer layer to emphasize its differences from previous concepts of a residual or intermediate layer. Estimates of the entrainment rate of dimethyl sulfide (DMS) and aerosol particles between the boundary layer and the buffer layer demonstrated that exchange occurred across the interface between these two layers in both upward and downward directions, In situ measurements of aerosol particles revealed highly concentrated, nucleation-mode aerosol particles between 10 and 30 nm diameter at the beginning of the first Lagrangian B flight in the buffer layer, while few were present in the boundary layer. Observations during the second and third flights indicate that aerosol particles of this size were mixing downward into the boundary layer from the buffer layer while DMS was transported upward. This fortuitous enhancement of aerosol particles in the buffer layer allowed simultaneous use of DMS and aerosol particle budgets to track the bidirectional entrainment rates. These estimates were compared to those from measurements of mean vertical motion and boundary layer growth rate, and from estimates of the fluxes and changes in concentration across the layer interface. In addition, three different techniques were used to estimate DMS emission rates from the ocean surface and showed good agreement: (1) evalulation of the DMS and aerosol mean concentration budgets, (2) seawater DMS concentrations and an air-sea exchange velocity, and (3) the mixed-layer gradient technique. C1 Princeton Univ, Dept Chem Engn, Princeton, NJ 08648 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. Monash Univ, Dept Math, Clayton, Vic 3168, Australia. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Russell, LM (reprint author), Princeton Univ, Dept Chem Engn, A317 Engn Quadrangle, Princeton, NJ 08648 USA. EM lrussell@princeton.edu; lenschow@ucar.edu; krista@raf.atd.ucar.edu; paul.krummel@dar.csiro.au; siems@monsoon.maths.monash.edu.au; arb@ac1.chemistry.drexel.edu; dct@ac2.chemistry.drexel.edu; bates@pmel.noaa.gov RI Krummel, Paul/A-4293-2013; Siems, Steven/C-8339-2013; Bates, Timothy/L-6080-2016; OI Krummel, Paul/0000-0002-4884-3678; Siems, Steven/0000-0002-8478-533X; LENSCHOW, DONALD/0000-0003-4353-0098 NR 21 TC 66 Z9 66 U1 1 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16411 EP 16432 DI 10.1029/97JD03437 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200033 ER PT J AU Suhre, K Mari, C Bates, TS Johnson, JE Rosset, R Wang, Q Bandy, AR Blake, DR Businger, S Eisele, FL Huebert, BJ Kok, GL Mauldin, RL Prevot, ASH Schillawski, RD Tanner, DJ Thornton, DC AF Suhre, K Mari, C Bates, TS Johnson, JE Rosset, R Wang, Q Bandy, AR Blake, DR Businger, S Eisele, FL Huebert, BJ Kok, GL Mauldin, RL Prevot, ASH Schillawski, RD Tanner, DJ Thornton, DC TI Physico-chemical modeling of the First Aerosol Characterization Experiment (ACE 1) Lagrangian B - 1. A moving column approach SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; EQUATORIAL PACIFIC; DIMETHYL SULFIDE; OZONE; PHOTODISSOCIATION; ATMOSPHERE; SIMULATION; CLOUDS; GAS; MICROPHYSICS AB During Lagrangian experiment B (LB in the following) of the First Aerosol Characterization Experiment (ACE 1): a clean maritime air mass was followed over a period of 28 hours. During that time span, the vertical distribution of aerosols and their gas phase precursors were characterized by a total of nine aircraft soundings which were performed during three research flights that followed the trajectory of a set of marked tetroons. The objective of this paper is to study the time evolution of gas phase photochemistry in this Lagrangian framework. A box model approach to the wind shear driven and vertically stratified boundary layer is questionable, since its basic assumption of instantaneous turbulent mixing of the entire air column is not satisfied here. To overcome this obstacle, a one-dimensional Lagrangian boundary layer meteorological model with coupled gas phase photochemistry is used. To our knowledge, this is the first time that such a model is applied to a Lagrangian experiment and that enough measurements are available to fully constrain the simulations. A major part of this paper is devoted to the question of to what degree our model is able to reproduce the time evolution and the vertical distribution of the observed species. Comparison with observations of O-3, OH, H2O2, CH3OOH, DMS, and CH3I, made on the nine Lagrangian aircraft soundings shows that this is in general the case, although the dynamical simulation started to deviate from the observations on the last Lagrangian flight. In agreement with experimental findings reported by Q.Wang et al. (unpublished manuscript, 1998b), generation of turbulence in the model appears to be most sensitive to the imposed sea surface temperature. Concerning the different modeled and observed chemical species, a number of conclusions are drawn: (1) Ozone, having a relatively long photochemical lifetime in the clean marine boundary layer, is found to be controlled by vertical transport processes, in particular synoptic-scale subsidence or ascent. (2) Starting with initally constant vertical profiles, the model is able to "create'' qualitatively the vertical structure of the observed peroxides. (3) OH concentrations are in agreement with observations, both on cloudy and noncloudy days. On the first flight, a layer of dry ozone rich air topped the boundary layer. The model predicts a minimum in OH and peroxides at that altitude consistent with observations. (4) Atmospheric DMS concentrations are modeled correctly only when using the Liss and Merlivat [1986] flux parameterization, the Wanninkhof [1992] flux parameterization giving values twice those observed. To arrive at this conclusion, OH is assumed to be the major DMS oxidant, but no assumptions about mixing heights or entrainment rates are necessary in this type of model. DMS seawater concentrations are constrained by observations. C1 Univ Toulouse 3, Lab Aerol, UMR CNRS UPS 5560, F-31400 Toulouse, France. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Hawaii Manoa, Dept Meteorol, Honolulu, HI 96822 USA. Natl Ctr Atmospher Res, ACD, Boulder, CO 80307 USA. Univ Hawaii Manoa, Dept Oceanog, Honolulu, HI 96822 USA. Natl Ctr Atmospher Res, RAF, Boulder, CO 80307 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. USN, Postgrad Sch, Monterey, CA 93943 USA. RP Suhre, K (reprint author), Univ Toulouse 3, Lab Aerol, UMR CNRS UPS 5560, F-31400 Toulouse, France. EM suhk@aero.obs-mip.fr RI Prevot, Andre/C-6677-2008; Bates, Timothy/L-6080-2016; OI Prevot, Andre/0000-0002-9243-8194; Suhre, Karsten/0000-0001-9638-3912 NR 51 TC 43 Z9 43 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16433 EP 16455 DI 10.1029/98JD00821 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200034 ER PT J AU Mari, C Suhre, K Bates, TS Johnson, JE Rosset, R Bandy, AR Eisele, FL Mauldin, RL Thornton, DC AF Mari, C Suhre, K Bates, TS Johnson, JE Rosset, R Bandy, AR Eisele, FL Mauldin, RL Thornton, DC TI Physico-chemical modeling of the First Aerosol Characterization Experiment (ACE 1) Lagrangian B - 2. DMS emission, transport and oxidation at the mesoscale SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; BIOGEOCHEMICAL SULFUR CYCLE; SHORT-TERM VARIABILITY; DIMETHYL SULFIDE; BIOGENIC SULFUR; 3-DIMENSIONAL MODEL; PACIFIC-OCEAN; GAS-EXCHANGE; ATMOSPHERE; FLUX AB A three-dimensional mesoscale meteorological model was used to study the interplay between the dynamical (turbulent mixing and advection) and physico-chemical (sea-air flux and photochemical sink by OH) processes that control dimethylsulfide DMS concentrations and their distribution in the marine boundary layer (MBL) during the First Aerosol Characterization Experiment ACE 1, Atmospheric DMS concentrations were constrained using observed seawater DMS concentrations and box model derived OH concentrations. Lateral boundary values of dynamical parameters were derived from the 6-hourly meteorological analysis of the European Centre for Medium-Range Weather Forecasts. Calculated DMS concentrations, wind speed and direction, and cloud cover were compared with measurements made aboard the RN Discoverer and on the three NCAR/C130 aircraft flights during the LagB experiment. Model-generated atmospheric DMS concentrations agreed with the DMS observations from the NCAR/C130 aircraft flights during the LagB experiment (R-2 = 0.69) assuming OH is the only oxidant and DMS flux parameterization based on Liss and Merlivat [1986], Comparison with Eulerian measurements made aboard the RN Discoverer showed that the model simulated the range of observed values but not the hour-to-hour variation observed in the atmospheric DMS concentrations. Part of the discrepancy was attributed to uncertainties in DMS sea-to-air transfer velocity, small scale features of seawater DMS that are beyond the model resolution, and uncertainties in the venting of the boundary layer by shallow clouds. A quantitative budget at the ship location revealed a strong impact of advection processes in determining DMS levels and temporal evolution. The three-dimensional mesoscale meteorological model was also used to estimate the effect of the low spatial resolution used in global models on seawater DMS concentrations and atmospheric OH concentrations. C1 Univ Toulouse 3, UMR 5560 CNRS, Lab Aerol, F-31400 Toulouse, France. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. RP Mari, C (reprint author), Univ Toulouse 3, UMR 5560 CNRS, Lab Aerol, F-31400 Toulouse, France. EM marc@aero.obs-mip.fr RI Bates, Timothy/L-6080-2016; OI Suhre, Karsten/0000-0001-9638-3912 NR 55 TC 15 Z9 15 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16457 EP 16473 DI 10.1029/98JD01068 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200035 ER PT J AU Middlebrook, AM Murphy, DM Thomson, DS AF Middlebrook, AM Murphy, DM Thomson, DS TI Observations of organic material in individual marine particles at Cape Grim during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLOUD-CONDENSATION-NUCLEI; MICROPROBE MASS ANALYSIS; SEA-SALT PARTICLES; BOUNDARY-LAYER; NORTH-SEA; BURSTING BUBBLES; SURFACE; AIR; ATMOSPHERE; ENRICHMENT AB During the First Aerosol Characterization Experiment (ACE 1) field campaign in November and December 1995, the particle analysis by laser mass spectrometry instrument was used to measure the composition of ambient particles in situ at Cape Grim, Tasmania, under various conditions ranging from clean marine air to moderately polluted air. Internal mixtures of sea-salt compounds and organic species were detected in over half of the negative spectra during clean marine conditions and in about 62% of the negative spectra during polluted conditions. In clean marine air masses, aerosol organics appeared to have two distinct source mechanisms depending on the extent of aerosol aging. Organic peaks had a positive trend with sodium sulfate peaks, indicating that organics and excess sulfate may accumulate in aged marine aerosol particles by similar mechanisms. When the sodium sulfate content was low, iodine had a positive trend with organics, which is consistent with organics and iodine originating from the surface-active layer of the ocean and becoming incorporated into fresh marine particles by bursting bubbles. Based on limited laboratory calibrations, the average organic mass is estimated to be of the order of 10% of the sea-salt content and is consistent with some of the missing mass fraction for Cape Grim particles (S. Howell et al., manuscript in preparation, 1997), which is the measured difference between gravimetric and ionic mass. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Middlebrook, AM (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM amiddlebrook@al.noaa.gov; murphyd@al.noaa.gov; dthomson@al.noaa.gov RI Middlebrook, Ann/E-4831-2011; Murphy, Daniel/J-4357-2012 OI Middlebrook, Ann/0000-0002-2984-6304; Murphy, Daniel/0000-0002-8091-7235 NR 56 TC 215 Z9 216 U1 0 U2 35 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16475 EP 16483 DI 10.1029/97JD03719 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200036 ER PT J AU Murphy, DM Thomson, DS Middlebrook, AM Schein, ME AF Murphy, DM Thomson, DS Middlebrook, AM Schein, ME TI In situ single-particle characterization at Cape Grim SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INDIVIDUAL AEROSOL-PARTICLES; MASS-SPECTROMETRY; SULFUR; SULFATE; SIZE AB This paper describes operation of the particle analysis by laser mass spectrometry (PALMS) instrument at Cape Grim. Several changes to the instrument improved the uniformity of ionization, simplified data analysis, and reduced the minimum analyzable particle size to 0.16 I-lm Almost all of the particles analyzed by PALMS at Cape Grim during clean marine conditions contained some sea salt. Almost all of the sulfate found during clean marine conditions was mixed with sea salt rather than in separate ammonium sulfate or sulfuric acid aerosols. Metals such as Cr, Fe, and Sn were detected in a few particles even in clean marine air masses. An NO+ peak in the mass spectra was associated with Mg, Ca, and Sr. This association could be caused either by the water retention of various salts or by different reactivities. It provides a reminder that other components of sea salt besides NaCl need to be considered for heterogeneous chemistry. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Murphy, DM (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM murphyd@al.noaa.gov; dthomson@al.noaa.gov; amiddlebrook@al.noaa.gov; mschein@al.noaa.gov RI Middlebrook, Ann/E-4831-2011; Murphy, Daniel/J-4357-2012 OI Middlebrook, Ann/0000-0002-2984-6304; Murphy, Daniel/0000-0002-8091-7235 NR 31 TC 61 Z9 63 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16485 EP 16491 DI 10.1029/97JD03281 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200037 ER PT J AU Kreidenweis, SM McInnes, LM Brechtel, FJ AF Kreidenweis, SM McInnes, LM Brechtel, FJ TI Observations of aerosol volatility and elemental composition at Macquarie Island during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE AEROSOL; SIZE; DIMETHYLSULFIDE; PARTICLES; SULFATE; REGIONS; NUCLEI; CARBON; OCEAN; ACID AB A combined thermal/electron microscopy technique was used to analyze marine aerosol samples from Macquarie Island (54 degrees 30'S, 158 degrees 57'E), obtained during November and December 1995 as part of the First Aerosol Characterization Experiment (ACE I). The analyses were performed for two size fractions, 80 < D-p, < 200 nm and D-p, > 200 nm. Sulfate particles were primarily observed in the 80 < D-p, < 200 nm fraction and were deduced to be present also at smaller sizes from the volatile response of the aerosol. In two of the samples early in the experiment, sulfate particles appeared to be partially or fully neutralized, but the particles in later samples from clean marine air masses were more volatile, suggesting a sulfuric or methanesulfonic acid composition. Sea-salt particles dominated the number concentrations of particles with D-p, > 200 nm and also contributed significantly to the number concentrations in the 80 < D-p, < 200 nm fraction. Evidence for increased sea-salt number concentrations at higher wind speeds was found. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Kreidenweis, SM (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. EM soniak@aerosol.atmos.colostate.edu; lmcinnes@lynx.sni.net; fredb@aerosol.atmos.colostate.edu RI Kreidenweis, Sonia/E-5993-2011 OI Kreidenweis, Sonia/0000-0002-2561-2914 NR 27 TC 19 Z9 20 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16511 EP 16524 DI 10.1029/98JD00800 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200039 ER PT J AU Quinn, PK Coffman, DJ Kapustin, VN Bates, TS Covert, DS AF Quinn, PK Coffman, DJ Kapustin, VN Bates, TS Covert, DS TI Aerosol optical properties in the marine boundary layer during the First Aerosol Characterization Experiment (ACE 1) and the underlying chemical and physical aerosol properties SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SIZE DISTRIBUTION; STRONG ELECTROLYTES; REFRACTIVE-INDEX; URBAN AEROSOL; SULFUR CYCLE; PACIFIC; MODEL; PARTICLES; SULFATE; NITRATE AB Measurements were made onboard the NOAA R/V Discoverer during the First Aerosol Characterization Experiment (ACE 1) to understand the optical properties of a minimally perturbed natural aerosol system in terms of its chemical and physical properties. ACE I took place during November and December of 1995 in the Southern Ocean region south of Australia. Reported here are observations at a wavelength of 550 nm of the submicron and supermicron aerosol scattering coefficient, sigma(sp); single scattering albedo, omega(o); and the hemispheric backscattered fraction and mass scattering efficiencies of son-sea-salt sulfate, sea salt, and the total aerosol. Also presented is the Angstrom exponent, (a) over circle, for the 450 and 700 nm wavelength pair. Variations in these parameters were found to be a strong function of the relative concentrations and size distributions of the dominant aerosol chemical components. Both the submicron and supermicron aerosol mass were composed primarily of water-soluble ionic species. This is in agreement with an experiment-average single scattering albedo of 0.99 (-0.4, +1.0%). Of the submicron ionic mass, 80 +/- 10% was sea salt, 16 +/- 8% was non-sea-salt sulfate, and 4 +/- 3% was methanesulfonate. Sea salt composed 99 +/- 0.70% of the supermicron ionic mass. The magnitude of scattering by both submicron and supermicron;aerosol was controlled by sea salt. The backscattered fraction for the submicron aerosol averaged 0.11 +/- 0.02 and was controlled by the tailing of coarse mode sea-salt mass into the submicron size range. Calculated mass scattering efficiencies for submicron non-sea-salt sulfate ion averaged 1.5 +/- 0.74 m(2) g(-1) (at 30 to 45% relative humidity) with the highest values corresponding to continentally influenced air masses where sulfate aerosol surface mean diameters and surface area concentrations were the largest. Mass scattering efficiencies for submicron sea salt were higher(averaging 4.2 +/- 0.96 m(2) g(-1)) due to the tailing of coarse mode sea salt into the particle size range most efficient for light scattering. Given the similar lifetimes of submicron non-sea-salt sulfate and sea salt in the marine boundary layer, it is evident that sea salt controls the aerosol optical properties in this Southern Ocean region. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Quinn, PK (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM quinn@pmel.noaa.gov; derek@pmel.noaa.gov; kapustin@soest.hawaii.edu; bates@pmel.noaa.gov; d.covert@u.washington.edu RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 41 TC 114 Z9 118 U1 2 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16547 EP 16563 DI 10.1029/97JD02345 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200042 ER PT J AU Carrico, CM Rood, MJ Ogren, JA AF Carrico, CM Rood, MJ Ogren, JA TI Aerosol light scattering properties at Cape Grim, Tasmania, during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTHROPOGENIC AEROSOLS; CLIMATE; SULFATE AB Large uncertainties remain in understanding the effects of ambient aerosols on climate. As part of the First Aerosol Characterization Experiment (ACE 1,November 15 to December 15, 1995), the total light scattering and backscattering coefficients by particles (sigma(sp), and sigma(bsp)) were measured at Cape Grim, Tasmania. Such measurements were made to characterize aerosol radiative forcing relevant to climate change at a southern hemisphere site. A controlled relative humidity (RH) nephelometry system (humidograph) was used to measure the dependence of sigma(sp) and sigma(bsp) upon controlled RH, upper particle diameter (D-p), and wavelength of light(lambda). Parameters derived from the measurements necessary to incorporate aerosols into climate models include the dependence of light scattering on aerosol hygroscopic growth(f(RH)) and the hemispheric backscatter fraction (b), both as functions of wavelength of light. Differences in parameter values during clean marine and non-clean-marine time periods were greatest for sigma(sp) and sigma(bsp) for D-p less than or equal to 1 mu m and were least for f(RH) and b. During clean marine conditions, for D-p, less than or equal to 10 mu m, and at lambda=550 nm, means and standard deviations of key parameters measured included f(RH equal to 82%) = 1.98 +/- 0.08 for sigma(sp), f(RH equal to 82%)= 1.48 +/- 0.09 for sigma(bsp), b = 0.16 +/- 0.01 at RH equal to 22%, and b = 0.12 +/- 0.03 at RH equal to 82%. These measurements contribute to characterizing aerosol optical properties at a remote marine site, serve as a basis of comparison to polluted sites, and may provide input to climate models. C1 Univ Illinois, Environm Sci & Engn Program, Dept Civil & Environm Engn, Urbana, IL 61801 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Carrico, CM (reprint author), Univ Illinois, Environm Sci & Engn Program, Dept Civil & Environm Engn, 3230 Newmark Civil Engn Lab MC-250,205 N Mathews, Urbana, IL 61801 USA. EM carrico@uiuc.edu; m-rood@uiuc.edu; jogren@cmd1.noaa.gov RI Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 34 TC 69 Z9 82 U1 3 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16565 EP 16574 DI 10.1029/98JD00685 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200043 ER PT J AU Quinn, PK Coffman, DJ AF Quinn, PK Coffman, DJ TI Local closure during the First Aerosol Characterization Experiment (ACE 1): Aerosol mass concentration and scattering and backscattering coefficients SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRONG ELECTROLYTES; REFRACTIVE-INDEX; URBAN AEROSOL AB The radiative effects of tropospheric aerosol particles are a complex function of the chemical, physical, and optical properties of the aerosol. Closure experiments provide a means for identifying and reducing uncertainties associated with these aerosol properties and hence with the estimation of aerosol radiative forcing. In a closure experiment, an aerosol property is measured by one or more methods and calculated from a model that is based on other independently measured properties. A comparison of the measured and calculated values can reveal inadequacies in either the measurements or the model. A goal of the Aerosol Characterization Experiments (ACE) is to reduce the uncertainty associated with estimating aerosol radiative forcing through both local and column closure experiments. The remote marine aerosol encountered during ACE I was well suited for such closure studies because of its relatively simple chemical composition. Local closure experiments were conducted on board the NOAA RV Discoverer focusing on the aerosol mass concentration and scattering and backscattering coefficients. Aerosol mass was determined by gravimetric analysis, ion chromatography, and by converting the number size distribution to a mass distribution. Scattering and backscattering coefficients were measured with an integrating nephelometer and calculated from a Mie scattering model. The different measures of mass agreed for both the submicron and supermicron aerosol indicating that within experimental uncertainty, the aerosol was composed entirely of ionic species and associated water mass. Measured and calculated values of scattering and backscattering coefficients for submicron aerosol agreed within experimental uncertainty. There was an offset, however, between the Mie-calculated true values and the measured values that is not explained by nonidealities of the nephelometer response. Closure was not obtained for scattering or backscattering in the supermicron size range due to inadequacies of the techniques used to measure the size distribution and scattering in this size range. Both the mass and the scattering closure experiments indicate a need for an improved understanding of the response of aerosol growth, mixing state, and scattering to changes in relative humidity. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. RP Quinn, PK (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 31 TC 62 Z9 63 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16575 EP 16596 DI 10.1029/97JD03757 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200044 ER PT J AU De Bruyn, WJ Bates, TS Cainey, JM Saltzman, ES AF De Bruyn, WJ Bates, TS Cainey, JM Saltzman, ES TI Shipboard measurements of dimethyl sulfide and SO2 southwest of Tasmania during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC SULFUR-DIOXIDE; OH; OXIDATION; MECHANISM; PHOTOOXIDATION; PHYTOPLANKTON; CHEMISTRY; DISULFIDE; KINETICS AB Measurements of seawater dimethylsulfide (DMS), atmospheric dimethylsulfide, and sulfur dioxide (SO2) were made on board the R/V Discoverer in the Southern Ocean, southeast of Australia, as part of the First Aerosol Characterization Experiment (ACE 1). The measurements covered a latitude range of 40 degrees S-55 degrees S during November-December 1995. Seawater DMS concentrations ranged from 0.4 to 6.8 nM, with a mean of 1.7 +/- 1.1 nM (1 sigma). The highest DMS concentrations were found in subtropical convergence zone waters north of 44 degrees S, and the lowest were found in polar waters south of 49 degrees S. In general, seawater DMS concentrations increased during the course of the study, presumably due to the onset of austral spring warming. Atmospheric DMS concentrations ranged from 24 to 350 parts per trillion by volume (pptv), with a mean of 112 +/- 61 pptv(1 sigma). Atmospheric SO2 was predominantly of marine origin with occasional anthropogenic input,;as evidenced by correlation with elevated Rn-222 and air mass trajectories. Concentrations ranged from 3 to 1000 pptv with a mean of 48.8 +/- 149 pptv (1 sigma) and a median 15.8 pptv. The mean SO2 concentration observed in undisturbed marine air was 11.9 +/- 7.6 pptv (1 sigma), and the mean DMS to SO2 ratio in these conditions was 13 +/- 9 (1 sigma). Diurnal variations in SO2 were observed, with a daytime maximum and early morning minimum in agreement with model simulations of DMS oxidation in the marine boundary layer. Steady state calculations and photochemical box model simulations suggest that the DMS to SO2 conversion efficiency in this region is 30-50%. Comparison of these results with results from warmer regions suggests that the DMS to SO2 conversion efficiency has a positive temperature dependence. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. CSIRO, Aspendale, Vic 3195, Australia. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. New Zealand Inst Water & Atmospher Res Ltd, Wellington, New Zealand. RP De Bruyn, WJ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Bates, Timothy/L-6080-2016 NR 37 TC 37 Z9 38 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16703 EP 16711 DI 10.1029/98JD00971 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200053 ER PT J AU Mauldin, RL Frost, GJ Chen, G Tanner, DJ Prevot, ASH Davis, DD Eisele, FL AF Mauldin, RL Frost, GJ Chen, G Tanner, DJ Prevot, ASH Davis, DD Eisele, FL TI OH measurements during the First Aerosol Characterization Experiment (ACE 1): Observations and model comparisons SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; ACID; PHOTODISSOCIATION; PHOTOLYSIS; MECHANISMS; ATMOSPHERE; CHEMISTRY; CLOUDS; OZONE AB Airborne measurements of the hydroxyl radical, OH, performed during the First Aerosol Characterization Experiment (ACE 1), using the Selected Ion Chemical Ionization Mass Spectrometry (SICIMS) technique are presented, Adaptations of the previous ground-based technique for measurement aboard an aircraft platform are discussed, including an inlet for the straightening and slowing of the airflow, calibration, and measurement considerations at changing pressure altitudes. Steady state model calculations of the concentration of OH, [OH], throughout the entire mission were generally in good agreement, with a slight bias toward an overestimate of the measured [OH]. The largest discrepancies between measured and modeled values occurred for measurements in the boundary layer, and those in and around clouds, with the model overestimating the [OH] by similar to 40% in the boundary layer or inside clouds, and underestimating it by similar to 30% near clouds. The low model [OH] near clouds can be attributed to underestimating the actinic flux calculated from Eppley radiometer measurements. The model overestimates in the boundary layer and inside clouds may in part be due to a lack of heterogeneous losses of HOx, species in the model. Models developed at the National Oceanic and Atmospheric Administration Aeronomy Laboratory and at Georgia Institute of Technology produce similar results with differences being attributed to the methods of calculating photolysis rates. Calculations of high noon [OH] for a flight out of Hobart using the O(D-1) quantum yields from Talukdar et al. [1998] produce 17% higher values than those calculated using the currently recommended Jet Propulsion Laboratory values. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NOAA, Environm Res Labs, Boulder, CO 80303 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Georgia Inst Technol, Georgia Tech Res Inst, Electroopt Environm & Mat Lab, Atlanta, GA 30332 USA. RP Mauldin, RL (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. RI Prevot, Andre/C-6677-2008; Frost, Gregory/I-1958-2013 OI Prevot, Andre/0000-0002-9243-8194; NR 38 TC 88 Z9 90 U1 4 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16713 EP 16729 DI 10.1029/98JD00882 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200054 ER PT J AU Kok, GL Prevot, ASH Schillawski, RD Johnson, JE AF Kok, GL Prevot, ASH Schillawski, RD Johnson, JE TI Carbon monoxide measurements fromm 76 degrees N to 59 degrees S and over the South Tasman Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB In November and December of 1995, carbon monoxide (CO) measurements were made in a Pacific transect and over the South Tasman Sea as part of the First Aerosol Characterization Experiment (ACE 1) program. Airborne CO measurements were made from 76 degrees N to 59 degrees S. A clear latitudinal gradient in CO concentrations was measured, with the southern hemisphere average about 80 parts per billion by volume (ppbv), and increasing to 120-130 ppbv at the most northern latitudes. Plumes of CO with a 30-40 ppbv concentration increase over the general background concentrations could be seen at several latitudes. The National Oceanic and Atmospheric Administration R/V Discoverer made CO measurements over the South Tasman Sea from November 15 to December 9 1995. A systematic decrease of 0.31 ppbv/d CO was observed. Vertical profile measurements of CO from near the ocean surface to 2500 m altitude during the Lagrangian B intensive of ACE 1 suggested the mixing of stratospheric air with reduced CO concentrations. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Natl Ctr Atmospher Res, Res Aviat Facil, Boulder, CO 80307 USA. RP Kok, GL (reprint author), Natl Ctr Atmospher Res, Res Aviat Facil, Box 3000, Boulder, CO 80307 USA. RI Prevot, Andre/C-6677-2008 OI Prevot, Andre/0000-0002-9243-8194 NR 18 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1998 VL 103 IS D13 BP 16731 EP 16736 DI 10.1029/98JD00527 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100RB UT WOS:000074828200055 ER PT J AU Agamalian, M Iolin, E Rusevich, L Glinka, CJ Wignall, GD AF Agamalian, M Iolin, E Rusevich, L Glinka, CJ Wignall, GD TI Back-face Bragg diffraction from a perfect and ultralightly deformed thick crystal SO PHYSICAL REVIEW LETTERS LA English DT Article AB The intensity of neutrons Bragg diffracted from the back face of a 9 mm thick slab-shaped Si(lll) analyzer crystal has been measured experimentally at the ORNL double crystal diffractometer and calculated theoretically. The back-face rocking curve of a strain-free perfect crystal contains two symmetrical peaks which become asymmetrical under an ultrasmall static deformation strain (bending with a radius of tens of km). The asymmetry is shown to be a sensitive measure of both the magnitude and direction of bending. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Inst Phys Energet, LV-1006 Riga, Latvia. NIST, Gaithersburg, MD 20899 USA. RP Agamalian, M (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. OI Wignall, George/0000-0002-3876-3244; Agamalian, Michael/0000-0002-9112-2534 NR 14 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 20 PY 1998 VL 81 IS 3 BP 602 EP 605 DI 10.1103/PhysRevLett.81.602 PG 4 WC Physics, Multidisciplinary SC Physics GA 100XJ UT WOS:000074840400027 ER PT J AU Faber, NM Duewer, DL Choquette, SJ Green, TL Chesler, SN AF Faber, NM Duewer, DL Choquette, SJ Green, TL Chesler, SN TI Characterizing the uncertainty in near-infrared spectroscopic prediction of mixed oxygenate concentrations in gasoline: Sample-specific prediction intervals SO ANALYTICAL CHEMISTRY LA English DT Article ID LEAST-SQUARES REGRESSION; IDENTIFICATION; RAMAN; ERROR; PLS AB Oxygenates are added to gasoline to reduce exhaust emission levels of carbon monoxide and to boost octane. The U.S. National Institute of Standards and Technology (NIST) provides 12 Standard Reference Materials (SRMs) for single oxygenates in reference gasoline. A previous study demonstrated the feasibility of nondestructively quantifying oxygenate concentration in SRM gasoline ampules using near-infrared (near-IR) spectroscopy combined with multivariate calibration techniques. A drawback of this approach has been that an average prediction uncertainty, rather than a sample-specific one, is obtained. Recent developments in multivariate calibration theory for prediction error variance cure this problem. This report characterizes the significant sources of uncertainties in multivariate calibration using principal component regression and partial least-squares, validating near-IR and other multivariate spectroscopic techniques for use in assigning certified values (expected value with specified uncertainty) to selected materials. This report interprets prediction results in terms of multivariate analytical figures of merit, enabling the visualization of complex multivariate models as univariate graphs. C1 Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Univ Washington, Ctr Proc Analyt Chem, Seattle, WA 98195 USA. RP Duewer, DL (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Duewer, David/B-7410-2008 NR 34 TC 55 Z9 55 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 15 PY 1998 VL 70 IS 14 BP 2972 EP 2982 DI 10.1021/ac971270b PG 11 WC Chemistry, Analytical SC Chemistry GA 100RP UT WOS:000074829400030 ER PT J AU Li, XL Baker, DN Temerin, M Cayton, T Reeves, GD Araki, T Singer, H Larson, D Lin, RP Kanekal, SG AF Li, XL Baker, DN Temerin, M Cayton, T Reeves, GD Araki, T Singer, H Larson, D Lin, RP Kanekal, SG TI Energetic electron injections into the inner magnetosphere during the Jan. 10-11, 1997 magnetic storm SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MARCH 24; SIMULATION; SAMPEX; SOLAR; SSC AB At the end of the main phase of the Jan. 10-11, 1997 magnetic storm, a rapid enhancement of 0.4-1.6 MeV electrons across L = 4.2-6 was measured by particle detectors on the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) and three Global Positioning System (GPS) satellites. This enhancement, over two orders of magnitude at L = 4.2-5, occurred around 11:00 UT on Jan. 10, when the AE index reached similar to 2000 nT and when a solar wind pressure pulse arrived. Using data from multiple satellites and ground stations, we determine that the rapid enhancement of 0.4-1.6 MeV electrons in the magnetosphere at L = 4.2-6 was due to a combination of intense substorm activity during the early part of the magnetic storm which produced a source population and the following pressure pulse which quickly energized some of these electrons by moving them into stronger magnetic field. C1 Univ Colorado, LASP, Boulder, CO 80303 USA. Univ Calif Berkeley, SSL, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Kyoto Univ, Dept Geophys, Kyoto 606, Japan. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hughes STX, Greenbelt, MD USA. RP Li, XL (reprint author), Univ Colorado, LASP, 1234 Innovat Dr, Boulder, CO 80303 USA. RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 15 TC 47 Z9 49 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1998 VL 25 IS 14 BP 2561 EP 2564 DI 10.1029/98GL00036 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 101UJ UT WOS:000074886300026 ER PT J AU Sun, DZ Trenberth, KE AF Sun, DZ Trenberth, KE TI Coordinated heat removal from the equatorial Pacific during the 1986-87 El Nino SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERANNUAL VARIABILITY; OCEAN; THERMOSTAT; ATMOSPHERE; MODEL; ENSO AB Utilizing radiation data from Earth Radiation Budget Experiment (ERBE), circulation statistics from NCEP reanalysis, and assimilated ocean data for the tropical Pacific basin, we show that the surface ocean warming during the 1986-87 El Nino is not only accompanied by significant increases in the cloud reflection of the solar radiation, but also by marked increases in the poleward energy transport in both the atmosphere and ocean, Measured over the equatorial region, the feedback from the ocean dynamics is twice as large as from the atmospheric dynamics which in turn is twice as large as the feedback from the cloud albedo. The three feedbacks constitute a strong regulatory effect upon the equatorial SST. The results reveal a prominent role of El Nino in the heat removal from the equatorial Pacific. C1 CU, CIRES, CDC, NOAA, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Sun, DZ (reprint author), CU, CIRES, CDC, NOAA, Campus Box 449, Boulder, CO 80309 USA. RI Trenberth, Kevin/A-5683-2012 OI Trenberth, Kevin/0000-0002-1445-1000 NR 20 TC 46 Z9 46 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1998 VL 25 IS 14 BP 2659 EP 2662 DI 10.1029/98GL01813 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 101UJ UT WOS:000074886300051 ER PT J AU Langford, AO O'Leary, TJ Masters, CD Aikin, KC Proffitt, MH AF Langford, AO O'Leary, TJ Masters, CD Aikin, KC Proffitt, MH TI Modulation of middle and upper tropospheric ozone at northern midlatitudes by the El Nino Southern Oscillation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VARIABILITY; MODEL; WAVE AB A five-year time series of lidar profiles from a site in Colorado is used to investigate the sources and scales of variability for ozone in the free troposphere. Analysis of 475 daily mean profiles derived from more than 25,000 individual profiles shows that similar to 66% of the total variance is due to fluctuations on time scales from I day to 1 month, similar to 30% on time scales from 1 month to 1 year, and similar to 4% on time scales greater than 1 year. The analysis also identifies low-frequency fluctuations correlated with the El Nino/Southern Oscillation (ENSO) (following a similar to 6-month lag) that may account for as much as 5% of the total variance in the data. The ENSO-related changes can also lead to apparent ozone trends that range from -0.2 to +0.5 ppbv/yr for different 10-year intervals between 1970 and 1990. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Langford, AO (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Langford, Andrew/D-2323-2009; Aikin, Kenneth/I-1973-2013 OI Langford, Andrew/0000-0002-2932-7061; NR 21 TC 27 Z9 27 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1998 VL 25 IS 14 BP 2667 EP 2670 DI 10.1029/98GL01909 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 101UJ UT WOS:000074886300053 ER PT J AU Stanton, TP Ostrovsky, LA AF Stanton, TP Ostrovsky, LA TI Observations of highly nonlinear internal solitons over the Continental Shelf SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Surface disturbances caused by strong, near-surface internal waves are widely seen in coastal regions as bands of slick and rough water propagating shoreward. These surface slicks are typically manifestations of optical and radar backscatter properties above internal solitons, and have strong surface current pulses associated with them. During a recent experiment studying coastal internal waves, extremely strong solitary internal wave packets were observed over a three week period on a very shallow and strongly stratified pycnocline off Northern Oregon. During periods of strongest tidal forcing, solitons were consistently observed on the leading edge of a semidiurnal internal tide bore, with pycnocline displacements up to 25m downward from a 7m initial depth in the first few solitons. The extreme nonlinearity of these internal waves is believed to be unique in ocean observations. This note characterizes these highly nonlinear Solitary Internal Waves (SIW) and presents a second order KdV model which reproduces the form of the displacements, and the small change in soliton width with amplitude predicted by this model. C1 USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. Univ Colorado, CIRES, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603600, Russia. RP Stanton, TP (reprint author), USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. OI Ostrovsky, Lev/0000-0003-2233-1305 NR 6 TC 119 Z9 121 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 15 PY 1998 VL 25 IS 14 BP 2695 EP 2698 DI 10.1029/98GL01772 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 101UJ UT WOS:000074886300060 ER PT J AU Krauss, M Wladkowski, BD AF Krauss, M Wladkowski, BD TI Vanadate complex spectroscopy at the RNase A active site SO INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY LA English DT Article; Proceedings Paper CT Satellite Symposium on Theoretical Chemistry in Biology - From Molecular Structure to Functional Mechanisms, of the 9th International Congress of Quantum Chemistry CY JUN 03-07, 1997 CL SAVANNAH, GEORGIA SP IBM Corp, Int Soc Quantum Biol & Pharmacol, Univ Florida, Dept Chem, Univ Florida, Div Sponsored Res, Univ Florida, Div Grad Educ, Mt Sinai Sch Med, Dept Physiol & Biophys, Univ Florida, Quantum Theory Project DE ab initio excitation energy; five-coordinate vanadate; ribonuclease active site; effective fragment potential ID TRANSITION-STATE-ANALOG; RIBONUCLEASE-A; NEUTRON-DIFFRACTION; PERTURBATION-THEORY; URIDINE VANADATE; POTENTIALS; INITIO; TRANSPHOSPHORYLATION; ADENOSINE; ETHYLENE AB Knowledge of the ionicity of the phosphorane intermediate is important to the analysis of the microscopic mechanism of the hydrolysis of the phosphate ester bond by ribonuclease A (RNase A). Five-coordinate uridine vanadate, an analog of the phosphorane, binds to RNase A as the monoanion. The absorption spectra of the vanadate is a probe of the electronic structure of the active site. An in vacuo theoretical model of H4VO5- is calculated to have transitions only in the far ultraviolet (UV). However, H2VO5C2H4- has one in the near UV as well as others further into the UV. The transition energy of the monoanion calculated in the field of the protein active site with effective fragment potentials shifts modestly to the red. Broad monoanion absorptions are predicted which would overlap an observed incomplete very broad absorption attributed to the complex of uridine vanadate with RNase A. The absorption bands of neutral ethylene glycol vanadate are predicted to be further to the red but also overlap the experimental absorption. (C) 1998 John Wiley & Sons, Inc. C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Western Maryland Coll, Dept Chem, Westminster, MD 21157 USA. RP Krauss, M (reprint author), NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. NR 27 TC 14 Z9 14 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0020-7608 J9 INT J QUANTUM CHEM JI Int. J. Quantum Chem. PD JUL 15 PY 1998 VL 69 IS 1 BP 11 EP 19 DI 10.1002/(SICI)1097-461X(1998)69:1<11::AID-QUA3>3.3.CO;2-1 PG 9 WC Chemistry, Physical; Mathematics, Interdisciplinary Applications; Physics, Atomic, Molecular & Chemical SC Chemistry; Mathematics; Physics GA ZV457 UT WOS:000074306500003 ER PT J AU Gaigalas, AK Reipa, V Niaura, G AF Gaigalas, AK Reipa, V Niaura, G TI Stark spectroscopy of tryptamine immobilized on a gold electrode SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article ID ELECTROREFLECTANCE; ADSORPTION; ABSORPTION; INTERFACE AB Electroreflectance (ER), ellipsometry, and surface-enhanced Raman spectroscopy (SERS) measurements were performed for immobilized tryptamine on polycrystalline gold electrodes, SERS study indicates that the indole ring does not interact directly with the gold surface. Ellipsometric measurements yielded a thickness of the tryptamine layer oft 1.98 +/- 0.05) nm and an inferred surface concentration of 3.3 x 10(-6) mol/m(2), ER measurements were performed in the wavelength region 200-300 nm using the NIST synchrotron ultraviolet radiation facility (SURF), The ER response was interpreted as a Stark shift in the tryptamine absorption line at 218 nm, Assuming that the tryptamine layer consists of two stacked tryptamine molecules associated at the indole rings, a unified analysis of ER and ellipsometric data gave the difference between the static dipole moments of the solvated ground and excited states of 0.65 x 10(-30) C m in low ionic strength buffer (0.01 IM PBS) and 0.25 x 10(-30) C m in high ionic strength buffer (0.01 M PBS + 1.0 M NaClO4), The results point to the importance of the composition of the solvation shell. Semiempirical quantum chemistry calculations of tryptamine molecules gave a qualitative explanation of the ER response in the low ionic buffer, The large ER response suggests that the method could be applied to the study of the tryptophan environment in adsorbed proteins. (C) 1998 Academic Press. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Gaigalas, AK (reprint author), NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. EM gaigalas@nist.-gov NR 24 TC 11 Z9 11 U1 3 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD JUL 15 PY 1998 VL 203 IS 2 BP 299 EP 310 DI 10.1006/jcis.1998.5509 PG 12 WC Chemistry, Physical SC Chemistry GA ZZ642 UT WOS:000074751600009 ER PT J AU Kline, SR Kaler, EW AF Kline, SR Kaler, EW TI Interactions in colloidal mixtures: Partial structure factors in mixtures of colloidal silica and an anionic oil-in-water microemulsion SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE small angle scattering; bimodal suspensions; microemulsions; contrast variation; structure factor ID ANGLE NEUTRON-SCATTERING; PERCUS-YEVICK APPROXIMATION; X-RAY-SCATTERING; PHASE-SEPARATION; BINARY-MIXTURES; BIS(2-ETHYLHEXYL) SULFOSUCCINATE; HARD-SPHERES; POLYSTYRENE; VISCOSITY; MICELLES AB We have investigated the colloidal stability and interactions in a mixture of colloidal silica (Ludox(TM)) and an oil-in-water microemulsion (AOT/decane/brine). Stable silica-microemulsion mixtures containing large fractions of dispersed phase (phi(oil) + phi(Ludox) > 0.36) can be prepared. For tired silica and AOT concentrations, the addition of decane increases the size of the microemulsion droplets. Since the surfactant concentration remains constant, this droplet growth is balanced by a decrease in the number density of droplets. Partial structure factors for the mixture are extracted from sets of small-angle neutron scattering (SANS) data using a solvent contrast variation technique. The extracted partial structure factors are compared qualitatively to model calculations for a multicomponent sticky hard sphere (SHS) fluid. A shallow contact potential (approximately 2.6 kT) between the Ludox particles is necessary to obtain agreement between model and experiment in the low-q region of the partial structure factors. The magnitude of this contact potential does not change with decane concentration, in agreement with the macroscopic observation that there is no observable change in the stability of these silica-microemulsion mixtures. (C) 1998 Academic Press. C1 Univ Delaware, Dept Chem Engn, Ctr Mol & Engn Thermodynam, Newark, DE 19716 USA. RP Kline, SR (reprint author), NIST, Ctr Neutron Res, Bldg 235,Rm E151, Gaithersburg, MD 20899 USA. NR 56 TC 18 Z9 18 U1 0 U2 11 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD JUL 15 PY 1998 VL 203 IS 2 BP 392 EP 401 DI 10.1006/jcis.1998.5543 PG 10 WC Chemistry, Physical SC Chemistry GA ZZ642 UT WOS:000074751600019 ER PT J AU Schlosser, P Smethie, WM Toggweiler, JR AF Schlosser, P Smethie, WM Toggweiler, JR TI Introduction to special section: Maurice Ewing Symposium on Applications of Trace Substance Measurements to Oceanographic Problems SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Editorial Material C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08540 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY USA. RP Schlosser, P (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RI Schlosser, Peter/C-6416-2012 OI Schlosser, Peter/0000-0002-6514-4203 NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1998 VL 103 IS C8 BP 15815 EP 15815 DI 10.1029/98JC01986 PG 1 WC Oceanography SC Oceanography GA ZZ547 UT WOS:000074741000019 ER PT J AU Broecker, WS Peacock, SL Walker, S Weiss, R Fahrbach, E Schroeder, M Mikolajewicz, U Heinze, C Key, R Peng, TH Rubin, S AF Broecker, WS Peacock, SL Walker, S Weiss, R Fahrbach, E Schroeder, M Mikolajewicz, U Heinze, C Key, R Peng, TH Rubin, S TI How much deep water is formed in the Southern Ocean? SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article; Proceedings Paper CT Maurice Ewing Symposium on Applications of Trace Substance Measurements to Oceanographic Problems CY OCT 16-20, 1995 CL ORACLE, ARIZONA ID WEDDELL SEA; BOTTOM WATER; CIRCULATION; RADIOCARBON; SALINITY; TEMPERATURE; MASSES AB Three tracers are used to place constraints on the production rate of ventilated deep water in the Southern Ocean. The distribution of the water mass tracer PO4* ("phosphate star") in the deep sea suggests that the amount of ventilated deep water produced in the Southern Ocean is equal to or greater than the outflow of North Atlantic Deep Water from the Atlantic. Radiocarbon distributions yield an export flux of water from the North Atlantic which has averaged about 15 Sv over the last several hundred years. CFC inventories are used as a direct indicator of the current production rate of ventilated deep water in the Southern Ocean. Although coverage is as yet sparse, it appears that the CFC inventory is not inconsistent with the deep water production rate required by the distributions of PO4* and radiocarbon. It has been widely accepted that the major part of the deep water production in the Southern Ocean takes place in the Weddell Sea. However, our estimate of the Southern Ocean ventilated deep water flux is in conflict with previous estimates of the flux of ventilated deep water from the Weddell Sea, which lie in the range 1-5 Sv. Possible reasons for this difference are discussed. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Princeton Univ, Dept Geol & Geophys Sci, Princeton, NJ 08544 USA. NOAA, Atlantic Oceanog & Meteorol Labs, Ocean Chem Div, Miami, FL 33149 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Broecker, WS (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NR 44 TC 117 Z9 119 U1 2 U2 27 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1998 VL 103 IS C8 BP 15833 EP 15843 DI 10.1029/98JC00248 PG 11 WC Oceanography SC Oceanography GA ZZ547 UT WOS:000074741000021 ER PT J AU Lupton, J AF Lupton, J TI Hydrothermal helium plumes in the Pacific Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article; Proceedings Paper CT Maurice Ewing Symposium on Applications of Trace Substance Measurements to Oceanographic Problems CY OCT 16-20, 1995 CL ORACLE, ARIZONA ID DE-FUCA RIDGE; LOIHI-SEAMOUNT; SOUTH-PACIFIC; NORTH PACIFIC; HAWAII; CIRCULATION; RISE; HE-3; ENTRAINMENT; VOLCANO AB Hydrothermal activity along the global mid-ocean ridge system and at active seamounts introduces a He-3-rich signal into the deep ocean basins, which can be used to trace patterns of ocean circulation and mixing. This hydrothermal helium signal is especially strong in the Pacific Ocean, where the spreading rate of the ridges is the greatest. In several areas of the Pacific the hydrothermal activity is of sufficient strength to produce intense helium plumes which clearly define the regional circulation. Among these are (1) a pair of helium plumes at 2500-m depth, which extend westward from the East Pacific Rise at 10 degrees N and 15 degrees S into the interior of the Pacific basin; (2) a helium plume at 2000-m depth extending southwest from sources on the Juan de Fuca Ridge in the northeast Pacific; and (3) a plume at 1100-m depth emanating from Loihi Seamount at 20 degrees N, which extends eastward from Hawaii to the coast of Mexico. The flow field implied by the helium distribution appears to be in reasonable agreement with Reid's [1997] steric height analysis for the Pacific. C1 NOAA, Pacific Marine Environm Lab, Newport, OR 97365 USA. RP Lupton, J (reprint author), NOAA, Pacific Marine Environm Lab, Newport, OR 97365 USA. NR 45 TC 75 Z9 76 U1 4 U2 22 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1998 VL 103 IS C8 BP 15853 EP 15868 DI 10.1029/98JC00146 PG 16 WC Oceanography SC Oceanography GA ZZ547 UT WOS:000074741000023 ER PT J AU Asher, W Wanninkhof, R AF Asher, W Wanninkhof, R TI Transient tracers and air-sea gas transfer SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article; Proceedings Paper CT Maurice Ewing Symposium on Applications of Trace Substance Measurements to Oceanographic Problems CY OCT 16-20, 1995 CL ORACLE, ARIZONA ID RELAXED EDDY ACCUMULATION; GRID-STIRRED TANK; WIND-WATER TUNNEL; MASS-TRANSFER; CARBON-DIOXIDE; FLUX MEASUREMENTS; TRANSFER VELOCITIES; BOMB RADIOCARBON; SURFACE-RENEWAL; CO2 EXCHANGE AB This paper provides a review of the physics and chemistry associated with air-sea gas transfer of transient atmospheric trace gases and the available laboratory and field measurement techniques used to study air-water gas transfer. The mechanistic principles and their relation to the measurement techniques are used to show that the error associated with estimating air-sea transfer velocities of transient tracers from transfer velocities measured using proxy tracers can be significant if an incorrect dependence of the transfer velocity on molecular diffusivity is assumed. Bubble-mediated transfer processes are also demonstrated to have a significant effect on the parameterization bf the transfer velocity. C1 Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Asher, W (reprint author), Univ Washington, Appl Phys Lab, 1013 NE 40th St, Seattle, WA 98105 USA. EM asher@crosby.apl.washington.edu NR 183 TC 33 Z9 33 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 1998 VL 103 IS C8 BP 15939 EP 15958 DI 10.1029/98JC00379 PG 20 WC Oceanography SC Oceanography GA ZZ547 UT WOS:000074741000028 ER PT J AU Hu, XD Kumar, S Polk, MB Vanderhart, DL AF Hu, XD Kumar, S Polk, MB Vanderhart, DL TI Synthesis and characterization of poly(benzobisthiazole) with tetramethylbiphenyl moiety in the main chain SO JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY LA English DT Article DE PBZT; polycondensation; tetramethylbiphenyl substituted ID PARA-AROMATIC POLYMERS; RIGID-ROD POLYMERS; THERMAL-PROPERTIES; CROSS-LINKING; UNITS AB Poly(benzobisthiazole)s containing an ortho-tetramethyl substituted biphenyl moiety were synthesized via the polycondensation of 2,5-diamino-1,4-benzenedithiol dihydrochloride with 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid in poly(phosphoric acid) (PPA). The intrinsic viscosities of the tetramethylbiphenyl poly(benzobisthiazole)s in chlorosulfonic acid at 30 degrees C were in the range of 6.9-13.4 dL/g. Copolycondensation of 2,5-diamino-1,4-benzenedithiol dihydrochloride with terephthalic acid and 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid was carried out as well by varying the ratio of the two dicarboxylic acid monomers in the reactant mixture. The homopolymers and copolymers were characterized by Fourier transform infrared spectroscopy (FTIR) and C-13 solid-state nuclear magnetic resonance spectroscopy (NMR). Thermal stability of the polymers was evaluated by thermogravimetric analysis (TGA) and thermogravimetric mass spectrum analysis (TG-MS). The tetramethylbiphenyl poly( benzobisthiazole)s were found to be more stable at elevated temperatures than the parent poly(p-phenylene benzobisthiazole) (PBZT). (C) 1998 John Wiley & Sons, Inc. C1 Georgia Inst Technol, Sch Text & Fiber Engn, Atlanta, GA 30332 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Polk, MB (reprint author), Georgia Inst Technol, Sch Text & Fiber Engn, Atlanta, GA 30332 USA. RI Kumar, Satish/F-7308-2011 NR 19 TC 8 Z9 8 U1 2 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-624X J9 J POLYM SCI POL CHEM JI J. Polym. Sci. Pol. Chem. PD JUL 15 PY 1998 VL 36 IS 9 BP 1407 EP 1416 DI 10.1002/(SICI)1099-0518(19980715)36:9<1407::AID-POLA8>3.0.CO;2-P PG 10 WC Polymer Science SC Polymer Science GA ZL893 UT WOS:000073484100008 ER PT J AU Hamilton, K AF Hamilton, K TI Effects of an imposed quasi-biennial oscillation in a comprehensive troposphere-stratosphere-mesosphere general circulation model SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NORTHERN-HEMISPHERE WINTER; EQUATORIAL PLANETARY WAVES; MIDDLE ATMOSPHERE; INTERANNUAL VARIABILITY; TOTAL OZONE; ZONAL WIND; OBSERVATIONAL EVIDENCE; DOWNWARD CONTROL; ANNUAL CYCLE; GLOBAL QBO AB A 48-yr integration was performed using the Geophysical Fluid Dynamics Laboratory SKYHI troposphere-stratosphere-mesosphere GCM with an imposed zonal momentum forcing designed to produce a quasi-biennial oscillation (QBO) in the tropical stratosphere. In response to this forcing, the model generates a QBO in the tropical circulation that includes some very realistic features, notably the asymmetry between the strength of the descending easterly and westerly shear zones, and the tendency for the initial westerly accelerations to appear quite narrowly confined to the equator. The extratropical circulation in the Northern Hemisphere (NH) winter stratosphere is affected by the tropical QBO in a manner similar to that observed. In particular, the polar vortex is generally weaker in winters in which there are easterlies in the tropical middle stratosphere. Roughly two-thirds of the largest midwinter polar warmings occur when the equatorial 30-mb winds are easterly, again in rough agreement with observations. Despite this effect, however, the total interannual variance in the zonal-mean extratropical circulation in the model apparently is slightly decreased by the inclusion of the tropical QBO. The observed QBO dependence of the winter-mean stratospheric extratropical stationary wave patterns is also quite well reproduced in the model. The QBO was also found to have a profound influence on stratospheric stationary waves at low latitudes. Near and above 10 mb the NH stationary waves were found to penetrate across the equator during the westerly QBO phase, but to be restricted to latitudes poleward of similar to 10 degrees N during the easterly phase. This means that the equatorial QBO in prevailing wind near and above 10 mb has a significant zonally asymmetric component. If this is also true in the real atmosphere, there are important implications for the adequacy of the current observational rawindsonde network near the equator. Analysis of the zonal-mean zonal momentum budget in the tropical stratosphere reveals that the resolved waves in the model are strong enough to force the realized accelerations through much of the QBO cycle. The exception appears to be the easterly acceleration phase below about 20 mb. The implications of this for the generation of a self-consistent QBO by GCMs will be considered. The effects of the imposed QBO on the troposphere were found to be very modest. There does appear to be a statistically significant weakening (by similar to 1 m s(-1)) of the high-latitude winter vortex in the middle and upper troposphere. Given the very high predictability of the stratospheric QBO itself, this effect could possibly be used to enhance the skill of seasonal weather forecasts. No significant QBO influence was found in the model precipitation field. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Hamilton, K (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 72 TC 57 Z9 57 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 15 PY 1998 VL 55 IS 14 BP 2393 EP 2418 DI 10.1175/1520-0469(1998)055<2393:EOAIQB>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 105PL UT WOS:000075082400002 ER PT J AU Bryant, GW Shirley, EL Goldner, LS McDaniel, EB Hsu, JWP Tonucci, RJ AF Bryant, GW Shirley, EL Goldner, LS McDaniel, EB Hsu, JWP Tonucci, RJ TI Theory of probing a photonic crystal with transmission near-field optical microscopy SO PHYSICAL REVIEW B LA English DT Article AB While near-field scanning optical microscopy (NSOM) can provide optical images with resolution much better than the diffraction limit, analysis and interpretation of these images is often difficult. We present a theory of probing with transmission NSOM that includes the effects of tip field, tip/sample coupling, light propagation through the sample, and light collection. We apply this theory to analyze experimental NSOM images of a nanochannel glass (NCG) array obtained in transmission mode. The NCG is a triangular array of dielectric rods in a dielectric glass matrix with a two-dimensional photonic band structure. We determine the modes for the NCG photonic crystal and simulate the observed data. The calculations show large contrast at low numerical aperture (NA) of the collection optics and detailed structure at high NA consistent with the observed images. We present calculations as a function of NA to identify how the NCG photonic modes contribute to and determine the spatial structure in these images. Calculations are presented as a function of tip/sample position, sample index contrast and geometry, and aperture size to identify the factors that determine image formation with transmission NSOM in this experiment. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Virginia, Dept Phys, Charlottesville, VA 22901 USA. USN, Res Lab, Washington, DC 20375 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 18 TC 21 Z9 21 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1998 VL 58 IS 4 BP 2131 EP 2141 DI 10.1103/PhysRevB.58.2131 PG 11 WC Physics, Condensed Matter SC Physics GA 104WU UT WOS:000075039700063 ER PT J AU Konrad, H Weissmuller, J Birringer, R Karmonik, C Gleiter, H AF Konrad, H Weissmuller, J Birringer, R Karmonik, C Gleiter, H TI Kinetics of gallium films confined at grain boundaries SO PHYSICAL REVIEW B LA English DT Article ID THIN-FILMS; GRAPHITE; TRANSITION AB We report on a combined study, by in situ x-ray diffraction at temperatures between 293 and 80 K, differential scanning calorimetry, and coherent quasielastic neutron scattering (QENS), of thin Ga films confined at grain boundaries in Al2O3-Ga nanocomposites that are produced by high-energy ball milling. We find that a molar fraction of Ga of up to 0.18 does not undergo phase change in the temperature interval investigated, which contains the bulk melting temperature T-M(bulk), and conclude that this Ga is located in confined layers at grain boundaries, with an estimated thickness of six atomic monolayers. In samples with a higher overall molar fraction, the Ga in excess of molar fraction 0.18 melts and crystallizes reversibly when cycled between 100 and 320 K. For such samples, QENS at 320 K, that is, 17 K above T-M(bulk), indicates three distinct diffusion coefficients D for Ga: one below the resolution limit, D-1<1x10(-6) cm(2)/s, one agreeing with the bulk liquid value, D-2=3.4x10(-5) cm(2)/s, and a faster coefficient D-3=2.4x10(-4) cm(2)/s. We argue that the smaller and medium diffusion coefficients, D-1 and D-2, represent, respectively, solidlike layers near the Al2O3-Ga interface and Liquid Ga in the core of interfacial layers and in liquid droplets. The fast diffusion coefficient (D-3) may be due to diffusion on free surfaces. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Univ Saarlandes, D-66041 Saarbrucken, Germany. RP Konrad, H (reprint author), Shonan Inst Technol, Tsujido Nishikaigan 1-1-25, Fujisawa, Kanagawa 251, Japan. RI Karmonik, Christof/B-6150-2009; Weissmuller, Jorg/C-3967-2009 OI Weissmuller, Jorg/0000-0002-8958-4414 NR 33 TC 24 Z9 24 U1 2 U2 19 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 1998 VL 58 IS 4 BP 2142 EP 2149 DI 10.1103/PhysRevB.58.2142 PG 8 WC Physics, Condensed Matter SC Physics GA 104WU UT WOS:000075039700064 ER PT J AU Dagata, JA Inoue, T Itoh, J Yokoyama, H AF Dagata, JA Inoue, T Itoh, J Yokoyama, H TI Understanding scanned probe oxidation of silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID FORCE MICROSCOPY; FABRICATION; FILMS AB A model for scanned probe microscope (SPM) silicon oxidation is presented. The model was derived from a consideration of the space-charge dependence of this solid-state reaction as a function of substrate doping type/level and has been verified experimentally by integrating an in situ electrical force characterization technique, scanning Maxwell stress microscopy (SMM), into the SPM fabrication process. This system enables us to obtain SPM topographic, SMM capacitance, and SMM surface potential information of nanometer-scale oxide features as a function of ionic concentrations within the growing oxide film. SPM oxide properties are compared to those of anodic and thermal oxides. The predictive power of the resulting model is demonstrated by showing how the growth rate and electrical character of the SPM-oxide features can be altered dramatically by modulating the applied oxidation voltage. (C) 1998 American Institute of Physics. [S0003-6951(98)01728-8]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Dagata, JA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 22 TC 95 Z9 95 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 13 PY 1998 VL 73 IS 2 BP 271 EP 273 DI 10.1063/1.121777 PG 3 WC Physics, Applied SC Physics GA 108PV UT WOS:000075275400047 ER PT J AU Glosik, J Bano, G Ferguson, EE Lindinger, W AF Glosik, J Bano, G Ferguson, EE Lindinger, W TI Selected ion flow drift tube study of the formation and dissociation of CO(+).N(2) ions in nitrogen buffer gas: the CO(+).N(2) bond energy SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion/molecule reactions; selected ion flow drift tube; CO(+).N(2) formation; CO(+).N(2) dissociation; CO(+)N(2) bond energy ID ASSOCIATION; SIFDT; CH3+; CO+; HCL AB Efficient vibrational quenching of CO(+) (v = 1) by N(2) led to the deduction of an unexpectedly strong attractive potential between CO(+) and N(2). This was subsequently confirmed by ab initio quantal calculations of the CO(+). N(2) bond strength. The bond energy of CO(+). N(2) has now been determined in a selected ion flow drift tube, by measuring collisional destruction and formation of CO(+). N(2). The bond energy is found to be 0.7 +/- 0.2 eV. This is sufficiently large to rationalize the fast vibrational quenching but somewhat less than an ab initio value. The large value of D(CO(+). N(2)) can unambiguously be explained by resonance interaction between CO(+). N, and the charge-transfer CO . N(2)(+) states. (C) 1998 Elsevier Science B.V. C1 Charles Univ Prague, Fac Math & Phys, Dept Elect & Vacuum Phys, Prague 8, Czech Republic. NOAA, CMDL, Boulder, CO 80303 USA. Univ Innsbruck, Inst Ionenphys, A-6020 Innsbruck, Austria. RP Glosik, J (reprint author), Charles Univ Prague, Fac Math & Phys, Dept Elect & Vacuum Phys, V Holeovickach 2, Prague 8, Czech Republic. RI Bano, Gregor/S-4884-2016 NR 26 TC 19 Z9 19 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD JUL 13 PY 1998 VL 176 IS 3 BP 177 EP 188 DI 10.1016/S1387-3806(98)14019-8 PG 12 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 111YZ UT WOS:000075467600003 ER PT J AU Matthews, MR Hall, DS Jin, DS Ensher, JR Wieman, CE Cornell, EA Dalfovo, F Minniti, C Stringari, S AF Matthews, MR Hall, DS Jin, DS Ensher, JR Wieman, CE Cornell, EA Dalfovo, F Minniti, C Stringari, S TI Dynamical response of a Bose-Einstein condensate to a discontinuous change in internal state SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLLECTIVE EXCITATIONS; MAGNETIC TRAP; GAS AB A two-photon transition is used to convert an arbitrary fraction of the Rb-87 atoms in a \F = 1, m(f) = -1] condensate to the \F = 2, m(f) = 1] state. Transferring the entire population imposes a discontinuous change on the condensate's mean-field repulsion, which leaves a residual ringing in the condensate width. A calculation based on Gross-Pitaevskii theory agrees well with the observed behavior, and from the comparison we obtain the ratio of the intraspecies scattering lengths for the two states, a(\1,)-(1)]/a(\2,1)] = 1.062(12). [S0031-9007(98)06574-0]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Trent, Dipartimento Fis, I-38050 Trent, Italy. Ist Nazl Fis Mat, I-38050 Trent, Italy. RP Matthews, MR (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. OI Dalfovo, Franco/0000-0001-6433-4112; Stringari, Sandro/0000-0002-5960-0612 NR 28 TC 212 Z9 214 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 13 PY 1998 VL 81 IS 2 BP 243 EP 247 DI 10.1103/PhysRevLett.81.243 PG 5 WC Physics, Multidisciplinary SC Physics GA ZZ635 UT WOS:000074750400001 ER PT J AU Hummer, DG Storey, PJ AF Hummer, DG Storey, PJ TI Recombination of helium-like ions - I. Photoionization cross-sections and total recombination and cooling coefficients for atomic helium SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE atomic data; atomic processes; line, formation ID LOW-DENSITY PLASMAS; R-MATRIX METHOD; LINE-INTENSITIES; OPACITY CALCULATIONS; GENERAL PROGRAM; HYDROGENIC IONS; ENERGY-LEVELS; F-VALUES AB A new calculation of photoionization cross-sections is described for the ground and excited states of atomic helium up to principal quantum number n = 25 and angular momentum quantum number l = 5. These cross-sections are used to calculate total recombination and cooling coefficients for atomic helium for electron temperatures given by log(T) = 1(0.2)4.4. A comparison of the threshold photoionization cross-sections obtained here with extrapolations of the highly accurate bound-bound oscillator strength calculations by Drake shows that the new calculations are in error by no more than 1 per cent. The accuracy of the photoionization cross-sections used by previous workers to derive recombination coefficients is also discussed. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. RP Hummer, DG (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 20 TC 55 Z9 55 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 11 PY 1998 VL 297 IS 4 BP 1073 EP 1078 DI 10.1046/j.1365-8711.1998.2970041073.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 105DP UT WOS:000075057700012 ER PT J AU Seo, DJ AF Seo, DJ TI Real-time estimation of rainfall fields using rain gage data under fractional coverage conditions SO JOURNAL OF HYDROLOGY LA English DT Article DE rainfall; estimation; fractional coverage; rain gage ID AREAL RAINFALL; RADAR; INTERPOLATION; PRECIPITATION AB Two new attempts at optimal estimation of rainfall fields using hourly rain gage data under fractional coverage conditions are reported; (1) double optimal estimation using analogues of indicator and simple kriging to estimate probability of rainfall and rainfall amount given raining, respectively, and (2) single optimal estimation using an analogue of simple kriging to directly estimate rainfall amount. They are evaluated via cross validation using hourly rain gage data from the operational network under the Tulsa, Oklahoma, WSR-88D (Weather Surveillance Radar-1988 Doppler version) umbrella. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Weather Serv, Hydrol Res Lab, Silver Spring, MD 20910 USA. RP Seo, DJ (reprint author), NOAA, Natl Weather Serv, Hydrol Res Lab, 1325 East West Highway, Silver Spring, MD 20910 USA. NR 26 TC 57 Z9 59 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD JUL 10 PY 1998 VL 208 IS 1-2 BP 25 EP 36 DI 10.1016/S0022-1694(98)00140-1 PG 12 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 104TZ UT WOS:000075032600003 ER PT J AU Seo, DJ AF Seo, DJ TI Real-time estimation of rainfall fields using radar rainfall and rain gage data SO JOURNAL OF HYDROLOGY LA English DT Article DE radar; rain gage; rainfall; estimation ID STOCHASTIC INTERPOLATION; BAYESIAN-APPROACH; GAUGES AB New attempts at real-time estimation of rainfall fields using rain gage and radar rainfall data are reported. Based on multiplicative decomposition of expectation of rainfall into conditional expectation sf rainfall given raining and probability of rainfall, the estimation procedures explicitly account for both within-storm variability of rainfall and variability due to fractional coverage of rainfall. As a result, in addition to the accuracy of radar rainfall data in estimating rainfall given that rainfall is successfully detected, that in discerning rainfall from no rainfall can also be taken into account. To evaluate the estimation procedures, cross validation was performed using hourly radar rainfall data from the Tulsa, Oklahoma, Weather Surveillance Radar-1988 Doppler version (WSR-88D) and hourly rain gage data under the radar umbrella. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Weather Serv, Hydrol Res Lab, Silver Spring, MD 20910 USA. RP Seo, DJ (reprint author), NOAA, Natl Weather Serv, Hydrol Res Lab, 1325 East West Highway, Silver Spring, MD 20910 USA. NR 39 TC 129 Z9 133 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD JUL 10 PY 1998 VL 208 IS 1-2 BP 37 EP 52 DI 10.1016/S0022-1694(98)00141-3 PG 16 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 104TZ UT WOS:000075032600004 ER PT J AU Tans, PP White, JWC AF Tans, PP White, JWC TI The global carbon cycle - In balance, with a little help from the plants SO SCIENCE LA English DT Editorial Material ID ATMOSPHERIC CO2; EXCHANGE; FOREST; MODEL C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Colorado, Dept Geol, Boulder, CO 80309 USA. RP Tans, PP (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RI White, James/A-7845-2009 OI White, James/0000-0001-6041-4684 NR 16 TC 24 Z9 29 U1 2 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 10 PY 1998 VL 281 IS 5374 BP 183 EP 184 DI 10.1126/science.281.5374.183 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZZ286 UT WOS:000074714200024 ER PT J AU Delaney, JR Kelley, DS Lilley, MD Butterfield, DA Baross, JA Wilcock, WSD Embley, RW Summit, M AF Delaney, JR Kelley, DS Lilley, MD Butterfield, DA Baross, JA Wilcock, WSD Embley, RW Summit, M TI The quantum event of oceanic crustal accretion: Impacts of diking at mid-ocean ridges SO SCIENCE LA English DT Review ID DE-FUCA RIDGE; EAST PACIFIC RISE; FLOOR ERUPTION SITE; 1993 COAXIAL EVENT; SEA-FLOOR; HYDROTHERMAL SYSTEMS; MIDOCEAN RIDGE; SUBMERSIBLE OBSERVATIONS; VOLCANIC-ERUPTION; HE-3/HEAT RATIOS AB Seafloor diking-eruptive events represent the irreducible, quantum events of upper oceanic crustal accretion. They record events by which a targe portion of the oceanic crust has formed through geological history. Since 1993, the U.S. Navy's real-time Sound Surveillance System has allowed Location of ongoing acoustic signatures of dike emplacement and basalt eruptions at ridge crests in the northeast Pacific. These diking-eruptive events trigger a sequence of related, rapidly evolving physical, chemical, and biological processes. Magmatic volatiles released during these events may provide nutrients for communities of subsea-floor microorganisms, some of which thrive in high-temperature anaerobic environments. Many of the organisms identified from these systems are Archaea. if microorganisms can thrive in the wafer-saturated pores and cracks within deep, volcanically active portions of our plane's, other hydrothermally active planets may harbor similar life forms. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NOAA, Pacific Marine Environm Lab, Newport, OR 97365 USA. RP Delaney, JR (reprint author), Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. RI Butterfield, David/H-3815-2016 OI Butterfield, David/0000-0002-1595-9279 FU NCIPC CDC HHS [OCE-9406965, OCE-9633572] NR 103 TC 139 Z9 144 U1 2 U2 14 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 10 PY 1998 VL 281 IS 5374 BP 222 EP 230 DI 10.1126/science.281.5374.222 PG 9 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZZ286 UT WOS:000074714200039 PM 11541731 ER PT J AU Kiselev, SB Rainwater, JC AF Kiselev, SB Rainwater, JC TI Enthalpies, excess volumes, and specific heats of critical and supercritical binary mixtures SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GLOBAL THERMODYNAMIC BEHAVIOR; NONASYMPTOTIC CRITICAL-BEHAVIOR; VAPOR-LIQUID-EQUILIBRIA; DIOXIDE + TOLUENE; CRITICAL REGION; FLUID MIXTURES; CRITICAL-POINT; 10 MPA; TEMPERATURES 298.15; CROSSOVER FUNCTIONS AB A scaling-law crossover thermodynamic model is applied to caloric properties of five binary mixtures, carbon dioxide + ethane, ethane + propane, n-pentane + benzene, n-pentane + acetone, and ammonia + water. Enthalpy increments, excess enthalpies, excess volumes, and specific heats are calculated on the phase boundaries and in the near-critical and supercritical one-phase regions, and calculated values agree well with experimental data. The method requires as input the mixture excess critical compressibility factor, as obtained from critical loci, which in this approach are determined from modified Leung-Griffiths correlations. The only additional variables needed are the acentric factors of the pure components and a few fitting parameters which describe the unknown thermodynamic energies along the critical locus and which are not needed for the phase boundary and supercritical properties in pressure-temperature-density space. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Kiselev, SB (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 82 TC 32 Z9 32 U1 1 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 8 PY 1998 VL 109 IS 2 BP 643 EP 657 DI 10.1063/1.476603 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FM UT WOS:000075255400035 ER PT J AU Glembocki, OJ Tuchman, JA Dagata, JA Ko, KK Pang, SW Stutz, CE AF Glembocki, OJ Tuchman, JA Dagata, JA Ko, KK Pang, SW Stutz, CE TI Electronic properties of GaAs surfaces etched in an electron cyclotron resonance source and chemically passivated using P2S5 SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR SURFACES; FERMI-LEVEL; N-TYPE; PHOTOREFLECTANCE; DAMAGE AB Photoreflectance has been used to study the electronic properties of (100) GaAs surfaces exposed to a Cl-2/Ar plasma generated by an electron cyclotron resonance source and subsequently passivated by P2S5. The plasma etch shifts the Fermi level of p-GaAs from near the valence band to midgap. but has no effect on n-GaAs. For ion energies below 250 eV, post-etch P2S5 chemical passivation removes the surface etch damage and restores the electronic properties to pre-etch conditions. Above 250 eV, the etch produces subsurface defects which cannot be chemically passivated. Auger electron spectroscopy shows that etching increases As at the GaAs/oxide interface, while passivation reduces it. (C) 1998 American Institute of Physics. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Wright Patterson Labs, Wright Patterson AFB, OH 45433 USA. US Dept Commerce, Div Precis Engn, Mfg Engn Lab, Div Technol, Washington, DC 20230 USA. RP Glembocki, OJ (reprint author), Optex Corp, Gaithersburg, MD 20899 USA. RI Pang, Stella/A-7770-2012 OI Pang, Stella/0000-0002-4330-0877 NR 17 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 6 PY 1998 VL 73 IS 1 BP 114 EP 116 DI 10.1063/1.121785 PG 3 WC Physics, Applied SC Physics GA 108PT UT WOS:000075275200039 ER PT J AU Hodges, JT Looney, JP van Zee, RD AF Hodges, JT Looney, JP van Zee, RD TI CRDS history SO CHEMICAL & ENGINEERING NEWS LA English DT Letter C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hodges, JT (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Hodges, Joseph/B-4578-2009 NR 6 TC 0 Z9 0 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2347 J9 CHEM ENG NEWS JI Chem. Eng. News PD JUL 6 PY 1998 VL 76 IS 27 BP 2 EP 2 PG 1 WC Chemistry, Multidisciplinary; Engineering, Chemical SC Chemistry; Engineering GA ZY169 UT WOS:000074593200003 ER PT J AU Quackenbush, SL Work, TM Balazs, GH Casey, RN Rovnak, J Chaves, A duToit, L Baines, JD Parrish, CR Bowser, PR Casey, JW AF Quackenbush, SL Work, TM Balazs, GH Casey, RN Rovnak, J Chaves, A duToit, L Baines, JD Parrish, CR Bowser, PR Casey, JW TI Three closely related herpesviruses are associated with fibropapillomatosis in marine turtles SO VIROLOGY LA English DT Article ID GREEN TURTLE; CUTANEOUS FIBROPAPILLOMAS; CHELONIA-MYDAS AB Green turtle fibropapillomatosis is a neoplastic disease of increasingly significant threat to the survivability of this species. Degenerate PCR primers that target highly conserved regions of genes encoding herpesvirus DNA polymerases were used to amplify a DNA sequence from fibropapillomas and fibromas from Hawaiian and Florida green turtles. All of the tumors tested (n = 23) were found to harbor viral DNA, whereas no viral DNA was detected in skin biopsies from tumor-negative turtles. The tissue distribution of the green turtle herpesvirus appears to be generally limited to tumors where viral DNA was found to accumulate at approximately two to five copies per cell and is occasionally detected, only by PCR, in some tissues normally associated with tumor development. in addition, herpesviral DNA was detected in fibropapillomas from two loggerhead and four olive ridley turtles. Nucleotide sequencing of a 483-bp fragment of the turtle herpesvirus DNA polymerase gene determined that the Florida green turtle and loggerhead turtle sequences are identical and differ from the Hawaiian green turtle sequence by five nucleotide changes, which results in two amino acid substitutions. The olive ridley sequence differs from the Florida and Hawaiian green turtle sequences by 15 and 16 nucleotide changes, respectively, resulting in four amino acid substitutions, three of which are unique to the olive ridley sequence. Our data suggest that these closely related turtle herpesviruses are intimately involved in the genesis of fibropapillomatosis. (C) 1998 Academic Press. C1 Cornell Univ, Coll Vet Med, Dept Microbiol & Immunol, Ithaca, NY 14853 USA. Cornell Univ, Coll Vet Med, James A Baker Inst Anim Hlth, Ithaca, NY 14853 USA. Natl Wildlife Hlth Res Ctr, Biol Resources Div, US Geol Survey, Honolulu, HI 96850 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Casey, JW (reprint author), Cornell Univ, Coll Vet Med, Dept Microbiol & Immunol, Ithaca, NY 14853 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 19 TC 100 Z9 105 U1 3 U2 11 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0042-6822 J9 VIROLOGY JI Virology PD JUL 5 PY 1998 VL 246 IS 2 BP 392 EP 399 DI 10.1006/viro.1998.9207 PG 8 WC Virology SC Virology GA ZY286 UT WOS:000074604900020 PM 9657957 ER PT J AU Bronk, DA Glibert, PM Malone, TC Banahan, S Sahlsten, E AF Bronk, DA Glibert, PM Malone, TC Banahan, S Sahlsten, E TI Inorganic and organic nitrogen cycling in Chesapeake Bay: autotrophic versus heterotrophic processes and relationships to carbon flux SO AQUATIC MICROBIAL ECOLOGY LA English DT Article DE nitrogen; Chesapeake Bay; dissolved organic nitrogen; dissolved organic carbon; C : N ratios ID N-15 TRACER METHOD; AMMONIUM UPTAKE; PHYTOPLANKTON; NUTRIENT; REGENERATION; PLANKTON; CONSUMPTION; DYNAMICS; BACTERIA; RELEASE AB To define the role of dissolved organic nitrogen (DON) in Chesapeake Bay (USA) nitrogen cycling, we performed experiments in the mesohaline Chesapeake Bay during 3 seasons: May, during the mid to late spring bloom, August, when patchy summer blooms often develop, and October, after the fall overturn. Every 3 h for 30 h we measured ambient nitrogen concentrations and used N-15 tracers to determine uptake and regeneration rates of NH4+ and urea, uptake rates of NO3- (NO2- was measured in October only), and rates of DON release due to NH4+ uptake. Autotrophic production and dissolved organic carbon (DOC) release were determined simultaneously using C-14 tracer techniques to compare with nitrogen flux rates. We found that first, the water column nitrogen demand exceeded nitrogen regeneration in May but nitrogen regeneration was over 3 times greater than the nitrogen demand in October. Second, mean rates of autotrophic DON release were highest in May but heterotrophic release was more important in summer and fall. Third, during all 3 studies, the C:N ratio of DOC to DON release rates was 3.4 to 4.5, indicating release of nitrogen-rich compounds. Release of dissolved organic matter (DOM) with a low C:N ratio was corroborated by an observed increase in DON concentrations from 7 to 42 mu g-at. N l(-1) from May to August and a concomitant decrease in the C:N ratio of the ambient DOM pool from 36.6 to 8.8. These data suggest that Chesapeake Bay is primarily autotrophic in the spring, but becomes progressively more heterotrophic later in the year. These data also suggest that DON is an important intermediate in this transition and serves as a Link between the allochthonous nitrogen-based autotrophic production in the spring and the autochthonous nitrogen-based heterotrophic system in the summer and fall. C1 Univ Georgia, Dept Marine Sci, Athens, GA 30602 USA. Univ Maryland, Horn Point Environm Lab, Ctr Environm Sci, Cambridge, MD 21613 USA. NOAA, Coastal Oceans Off, Silver Spring, MD 20910 USA. Univ Goteborg, Dept Gen & Marine Microbiol, S-41390 Gothenburg, Sweden. RP Bronk, DA (reprint author), Univ Georgia, Dept Marine Sci, Athens, GA 30602 USA. EM dbronk@arches.uga.edu RI glibert, patricia/G-1026-2013 OI glibert, patricia/0000-0001-5690-1674 NR 56 TC 86 Z9 88 U1 0 U2 22 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 EI 1616-1564 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD JUL 2 PY 1998 VL 15 IS 2 BP 177 EP 189 DI 10.3354/ame015177 PG 13 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 100TF UT WOS:000074830900007 ER PT J AU Snyder, KA AF Snyder, KA TI A numerical test of air void spacing equations SO ADVANCED CEMENT BASED MATERIALS LA English DT Article DE concrete; entrained air voids; freeze thaw; spacing equations ID NEIGHBOR DISTRIBUTION-FUNCTIONS; INTERPENETRABLE-SPHERE MODELS; FLOW LENGTH CONCEPT; FROST DURABILITY; CONCRETE; SYSTEMS; MEDIA; ENTRAINMENT; PERCOLATION; EFFICIENCY AB Air void spacing equations have been proposed in Nle literature by a number of authors: Powers; Philleo; Attiogbe; and Pleau and Pigeon. Each proposed spacing equation attempts to characterize the true "spacing" of entrained air voids in concrete. While efforts have been made to correlate these spacing equation calculations to freeze-thaw performance, no test has been performed to assess the geometrical accuracy of these spacing equations. Herein is a computerized accuracy test of these proposed spacing equations. A computer model of air void systems is used, and various "spacings" are measured in the model system. The results of these measurements are then compared to the appropriate spacing equation prediction, along with equations developed by Lu and Torquato. Published by Elsevier Science Ltd. C1 NIST, Bldg & Mat Div, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP NIST, Bldg & Mat Div, Bldg & Fire Res Lab, Bldg 226,Room B350, Gaithersburg, MD 20899 USA. NR 44 TC 24 Z9 25 U1 2 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1065-7355 J9 ADV CEM BASED MATER JI Adv. Cem. Based Mater. PD JUL PY 1998 VL 8 IS 1 BP 28 EP 44 DI 10.1016/S1065-7355(98)00007-8 PG 17 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA ZW187 UT WOS:000074384400003 ER PT J AU Merzbacher, CI Barker, JG Swider, KE Rolison, DR AF Merzbacher, CI Barker, JG Swider, KE Rolison, DR TI Structure of Ru-Ti oxide aerogels: a SANS study SO ADVANCES IN COLLOID AND INTERFACE SCIENCE LA English DT Article; Proceedings Paper CT TRI/Princeton Workshop on Characterization of Porous Materials - From Angstroms to Millimeters CY JUN 18-20, 1997 CL PRINCETON, NJ DE aerogel; SANS; contrast matching; ruthenium-titanium oxide; nanoscale structure ID ANGLE NEUTRON-SCATTERING; MORPHOLOGY AB Small-angle neutron scattering (SANS) has been used to characterize Ru-Ti oxide aerogels annealed under various atmospheres and temperatures. The pores were filled with H(2)O/D(2)O solutions that match the scattering properties of either RuO(2) or TiO(2), therefore scattering from the remaining unmatched phase is measured independently. The structure of the RuO(2), and TiO(2), components of the aerogel detected by SANS depends more on annealing temperature than annealing atmosphere. The results are consistent with a branched, polymeric network made up of 8-16 nm TiO(2), particles and < 5-nm RuO(2), particles. The SANS results are supported by TEM. This study demonstrates that contrast-matching SANS is complementary to other techniques for characterizing the structure of two-phase aerogels. Published by Elsevier Science B.V. C1 USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. USN, Res Lab, Div Chem, Washington, DC 20375 USA. RP Merzbacher, CI (reprint author), USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. EM merzbacher@nrl.navy.mil NR 21 TC 8 Z9 8 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0001-8686 J9 ADV COLLOID INTERFAC JI Adv. Colloid Interface Sci. PD JUL PY 1998 VL 76 BP 57 EP 69 DI 10.1016/S0001-8686(98)00041-4 PG 13 WC Chemistry, Physical SC Chemistry GA ZZ293 UT WOS:000074714900005 ER PT J AU Anderson, TL Ogren, JA AF Anderson, TL Ogren, JA TI Determining aerosol radiative properties using the TSI 3563 integrating nephelometer SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID LIGHT-SCATTERING; EXTINCTION AB Methods for reducing and quantifying the uncertainties in aerosol optical properties measured with the TSI 3563 integrating nephelometer are presented. For nearly all applications, the recommended calibration gases are air and CO,. By routinely characterizing the instrumental response to these gases, a diagnostic record of instrument performance can be created. This record can be used to improve measurement accuracy and quantify uncertainties due to instrumental noise and calibration drift. When measuring scattering by particles, size segregation upstream of the nephelometer at about I Crm aerodynamic diameter greatly increases the information content of the data for two reasons: one stemming from the independence of coarse and fine particles in the atmosphere, and the second stemming from the size dependence of the nephelometer response. For many applications (e.g., extinction budget studies) it is important to correct nephelometer data for the effects of angular nonidealities. Correction factors appropriate to a broad range of sampling conditions are given herein and are shown to be constrained by the wavelength dependence of light scattering, as measured by the nephelometer. Finally, the nephelometer measurement is nondestructive, such that the sampled aerosol can be further analyzed downstream. Data from two nephelometers operated in series are used to evaluate this procedure. A small loss of super-mu m particles (5-10%) is found, while the sub-mu m data demonstrates measurement reproducibility within +/- 1%. (C) 1998 American Association for Aerosol Research. C1 Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80803 USA. RP Anderson, TL (reprint author), Univ Washington, Joint Inst Study Atmosphere & Oceans, Box 351640, Seattle, WA 98195 USA. RI Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 21 TC 466 Z9 477 U1 1 U2 36 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD JUL PY 1998 VL 29 IS 1 BP 57 EP 69 DI 10.1080/02786829808965551 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZW158 UT WOS:000074381000006 ER PT J AU Fletcher, RA Dobbins, RA Chang, HC AF Fletcher, RA Dobbins, RA Chang, HC TI Mass spectrometry of particles formed in a deuterated ethene diffusion flame SO ANALYTICAL CHEMISTRY LA English DT Article ID SOOT AB Nanometer-sized spherule soot precursor particles have been collected by thermophoretic sampling from the interior of a laminar diffusion name and mass analyzed by laser microprobe mass spectrometry, Mass spectra of the precursor particles formed in an ethene diffusion name have indicated the presence of polycyclic aromatic hydrocarbons (PAHs) in the m/z range of 202-300 and higher mass peaks extending out to m/z 472. The mass resolution of the time-of-flight mass spectrometer used did not provide conclusive identification of PAHs because of ambiguities in assignment for the relative amounts of carbon and hydrogen (CxHy) for each PAH peak and the possibilities of spectral interferences. To determine the chemical formula that can be assigned to each molecular ion peak, an isotopically pure deuterated ethene (C2D4) fuel was burned in place of normal ethene (C2H4) in the diffusion flame. For the normal ethene fuel, mass peaks tentatively identified as C16H10 to C38H16 were obtained, Accordingly, deuterated PAH peaks ranging from C16D10 to C38D16 were found when C2D4 was burned. These m/z values correspond to molecular ion, Mi, peaks for an array of PAH compounds. The deuterated PAH mass peaks (CxDy) were entirely consistent with a mass shift of y mass units with respect to the normal PAH mass peaks. The carbonaceous particle aggregates collected from the upper name region have mass peaks characteristic of C-x(+) and CxH+, while the deuterated soot has C-x(+) and CxD+. The deuterated ethene experiment has verified the identities of x and y in the PAH (CxHy) compounds present in the precursor particle samples. No prior experiment using pure deuterium-based fuel as a combustion diagnostic to form aerosol-containing deuterated PAH compounds has been reported. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Brown Univ, Div Engn, Providence, RI 02912 USA. St Gobain Norton, Worcester, MA 01615 USA. RP Fletcher, RA (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 12 TC 22 Z9 23 U1 3 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 1 PY 1998 VL 70 IS 13 BP 2745 EP 2749 DI 10.1021/ac971293q PG 5 WC Chemistry, Analytical SC Chemistry GA ZY081 UT WOS:000074584700075 PM 21644789 ER PT J AU Lazutin, LL Rasinkangas, R Kozelova, TV Korth, A Singer, H Reeves, G Riedler, W Torkar, K Gvozdevsky, BB AF Lazutin, LL Rasinkangas, R Kozelova, TV Korth, A Singer, H Reeves, G Riedler, W Torkar, K Gvozdevsky, BB TI Observations of substorm fine structure SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article DE magnetospheric physics (storms and substorms) ID MAGNETOSPHERIC SUBSTORMS; GEOSYNCHRONOUS ORBIT; GROWTH-PHASE; MAGNETOTAIL; EXPANSION; ELECTRON; DYNAMICS; ENERGY; PRECIPITATION; SIGNATURES AB Particle and magnetic field measurements on the CRRES satellite were used, together with geosynchronous satellites and ground-based observations, to investigate the fine structure of a magnetospheric substorm on February 9, 1991. Using the variations in the electron fluxes, the substorm activity was divided into several intensifications lasting about 3-15 minutes each. The two main features of the data were: (1) the intensifications showed internal fine structure in the time scale of about 2 minutes or less. We call these shorter periods activations. Energetic electrons and protons at the closest geosynchronous spacecraft (1990 095) were found to have comparable activation structure. (2) The energetic (> 69 keV) proton injections were delayed with respect to electron injections, and actually coincided in time with the end of the intensifications and partial returns to locally more stretched field line configuration. We propose that the energetic protons could be able to control the dynamics of the system locally be quenching the ongoing intensification and possibly preparing the final large-scale poleward movement of the activity. It was also shown that these protons originated from the same intensification as the preceeding electrons. Therefore, the substorm instability responsible for the intensifications could introduce a negative feedback loop into the system, creating the observed fine structure with the intensification time scales. C1 Russian Acad Sci, Polar Geophys Inst, Apatity 184200, Murmansk Region, Russia. Univ Oulu, Dept Phys Sci, FIN-90570 Oulu, Finland. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. RP Russian Acad Sci, Polar Geophys Inst, Apatity 184200, Murmansk Region, Russia. RI Kozelova, Tamara/N-2760-2013; Reeves, Geoffrey/E-8101-2011; Gvozdevsky, Boris/A-5222-2017 OI Kozelova, Tamara/0000-0002-9942-7041; Reeves, Geoffrey/0000-0002-7985-8098; Gvozdevsky, Boris/0000-0003-1643-798X NR 39 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD JUL PY 1998 VL 16 IS 7 BP 775 EP 786 DI 10.1007/s005850050647 PG 12 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 107JT UT WOS:000075205200004 ER PT J AU Graczyk, TK Fayer, R Trout, JM Lewis, EJ Farley, CA Sulaiman, I Lal, AA AF Graczyk, TK Fayer, R Trout, JM Lewis, EJ Farley, CA Sulaiman, I Lal, AA TI Giardia sp. cysts and infectious Cryptosporidium parvum oocysts in the feces of migratory Canada geese (Branta canadensis) SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID GULLS; LARUS; HOST AB Fecal droppings of migratory Canada geese, Branta canadensis, collected from nine sites near the Chesapeake Bay (Maryland), were examined for the presence of Cryptosporidium parvum and Giardia spp. Cryptosporidium sp. oocysts were found in feces at seven of nine sites, and Giardia cysts were found at all nine sites. The oocysts from three sites were infectious for mice and molecularly identified as the zoonotic genotype of Cryptosporidium parvum. Waterfowl can disseminate infectious C. parvum oocysts in the environment. C1 Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD 21205 USA. USDA ARS, Immun & Dis Resistance Lab, Inst Livestock & Poultry Sci, Beltsville, MD 20705 USA. NOAA, US Dept Commerce, Cooperat Oxford Lab, Natl Marine Fisheries Serv, Oxford, MD 21654 USA. Ctr Dis Control & Prevent, Dept Parasit Dis, Natl Ctr Infect Dis, Chamblee, GA 30341 USA. RP Graczyk, TK (reprint author), Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, 615 N Wolfe St, Baltimore, MD 21205 USA. EM tgraczyk@jhsph.edu NR 18 TC 76 Z9 78 U1 2 U2 6 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD JUL PY 1998 VL 64 IS 7 BP 2736 EP 2738 PG 3 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA ZY646 UT WOS:000074644700066 PM 9647860 ER PT J AU Tarrio, C Watts, RN Lucatorto, TB Slaughter, JM Falco, CM AF Tarrio, C Watts, RN Lucatorto, TB Slaughter, JM Falco, CM TI Optical constants of in situ-deposited films of important extreme-ultraviolet multilayer mirror materials SO APPLIED OPTICS LA English DT Article ID THIN-FILMS; REFLECTION; 1216-A; 24-A; MO AB We have performed angle-dependent reflectance measurements of in situ magnetron sputtered films of B4C, C, Mo, Si, and W. The Fresnel relations were used to determine the complex index of refraction from the reflectance data in the region of approximately 35-150 eV. In the cases of Si, C, and B4C we found excellent agreement with published data. However, for Mo and W we found that the optical properties from 35 to 60 eV differed significantly from those in the Literature. C1 NIST, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. RP Tarrio, C (reprint author), NIST, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. NR 13 TC 34 Z9 35 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1998 VL 37 IS 19 BP 4100 EP 4104 DI 10.1364/AO.37.004100 PG 5 WC Optics SC Optics GA ZW479 UT WOS:000074415100006 PM 18285847 ER PT J AU Snail, KA Hanssen, LM AF Snail, KA Hanssen, LM TI Magnification of conic mirror reflectometers SO APPLIED OPTICS LA English DT Article AB Conic mirror reflectometers are used to measure the diffuse reflectance and total integrated scatter of surfaces. In spite of the long history of using conic mirrors for these purposes, the maximum magnification of the three primary types of conic mirror (hemisphere, hemiellipsoid, and dual paraboloid) had not been compared quantitatively. To our knowledge, an exact magnification formula has not been published for any of the three primary conic mirrors. The maximum magnification is needed for proper sizing of detectors and radiation sources used with reflectometers. Exact analytical expressions for the maximum magnification of a Coblentz hemisphere, a hemiellipsoid, and a dual-paraboloid mirror system are derived and compared. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Snail, KA (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 22 TC 6 Z9 6 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1998 VL 37 IS 19 BP 4143 EP 4149 DI 10.1364/AO.37.004143 PG 7 WC Optics SC Optics GA ZW479 UT WOS:000074415100013 PM 18285854 ER PT J AU Lehman, JH Aust, JA AF Lehman, JH Aust, JA TI Bicell pyroelectric optical detector made from a single LiNbO3 domain-reversed electret SO APPLIED OPTICS LA English DT Article AB Using electric-field poling at room temperature, we selectively reversed the direction of the spontaneous polarization in a 200-mu m-thick, z-cut LiNbO3 electret to produce a bicell pyroelectric detector. The detector required only a single set of electrodes, one electrode on the front surface and one on the back surface. Microphonic noise that is typical of monocell pyroelectric detectors is reduced in the present device. Our spatial uniformity data indicate that the optical response of one half of the bicell detector area was equal to and opposite the other half within 1.2%. The microphonic suppression of the bicell pyroelectric detector was less than -36 dB from 10 to 50 Hz and less than -118 dB at 35 Hz of that of a reference monocell pyroelectric detector. The substrate thickness is significantly greater than those of other domain-engineered pyroelectric detector designs and allows us to build practical, large-area detectors for radiometric applications. (C) 1998 Optical Society of America. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Lehman, JH (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 9 Z9 9 U1 2 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUL 1 PY 1998 VL 37 IS 19 BP 4210 EP 4212 DI 10.1364/AO.37.004210 PG 3 WC Optics SC Optics GA ZW479 UT WOS:000074415100023 PM 18285864 ER PT J AU Goessler, W Rudorfer, A Mackey, EA Becker, PR Irgolic, KJ AF Goessler, W Rudorfer, A Mackey, EA Becker, PR Irgolic, KJ TI Determination of arsenic compounds in marine mammals with high-performance liquid chromatography and an inductively coupled plasma mass spectrometer as element-specific detector SO APPLIED ORGANOMETALLIC CHEMISTRY LA English DT Article DE HPLC-ICP-MS; cetaceans; pinnipeds; arsenic; arsenobetaine; arsenocholine; whales; seals ID ATOMIC-ABSORPTION SPECTROMETRY; HYDRIDE GENERATION; ION CHROMATOGRAPHY; SPECIATION; ARSENOBETAINE; SAMPLES; TISSUES AB Total arsenic concentrations and the concentrations of individual arsenic compounds were determined in liver samples of pinnipeds [nine ringed seals (Phoca hispida), one bearded seal (Erginathus barbatus)] and cetaceans [two pilot whales (Globicephalus melas), one beluga whale (Deliphinapterus leucus)]. Total arsenic concentrations ranged from 0.167 to 2.40 mg As kg(-1) wet mass. The arsenic compounds extracted from the liver samples with a methanol/water mixture (9:1, v/v) were identified and quantified by anion- and cation-exchange chromatography, An ICP-MS equipped with a hydraulic high-pressure nebulizer served as the arsenic-specific detector. Arsenobetaine (0.052-1.67 mg As kg(-1) wet mass) was the predominant arsenic compound in all the liver samples. Arsenocholine was present in all livers (0.005-0.044 mg As kg(-1) wet mass). The tetramethylarsonium cation was detected in all pinnipeds (<0.009 to 0.043 mg As kg(-1)) but not in any of the cetaceans. The concentration of dimethylarsinic acid ranged from <0.001 to 0.109 mg As kg(-1) wet mass. Most of the concentrations for methylarsonic acid (<0.001 to 0.025 mg As kg(-1) wet mass) were below the detection limit. Arsenous acid and arsenic acid concentrations were below the detection limit of the method (0.001 mg As kg(-1)). An unknown arsenic compound was present in all liver samples at concentrations from 0.002-0.027 mg As kg(-1). (C) 1998 John Wiley & Sons, Ltd. C1 Karl Franzens Univ Graz, Inst Analyt Chem, A-8010 Graz, Austria. NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. NIST, Inst Analyt Chem, Charleston, SC 29412 USA. RP Goessler, W (reprint author), Karl Franzens Univ Graz, Inst Analyt Chem, Univ Pl 1, A-8010 Graz, Austria. OI Goessler, Walter/0000-0002-0142-9373 NR 32 TC 48 Z9 49 U1 1 U2 5 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0268-2605 EI 1099-0739 J9 APPL ORGANOMET CHEM JI Appl. Organomet. Chem. PD JUL PY 1998 VL 12 IS 7 BP 491 EP 501 DI 10.1002/(SICI)1099-0739(199807)12:7<491::AID-AOC740>3.3.CO;2-Y PG 11 WC Chemistry, Applied; Chemistry, Inorganic & Nuclear SC Chemistry GA 100JU UT WOS:000074813700005 ER PT J AU Kukkonen, JVK Landrum, PF AF Kukkonen, JVK Landrum, PF TI Effect of particle-xenobiotic contact time on bioavailability of sediment-associated benzo(a)pyrene to benthic amphipod, Diporeia spp SO AQUATIC TOXICOLOGY LA English DT Article DE sediments; bioavailability; organic contaminants; benzo(a)pyrene; contact time; sorption ID POLYCYCLIC AROMATIC-HYDROCARBONS; HYDROPHOBIC ORGANIC-COMPOUNDS; PONTOPOREIA-HOYI; NATURAL SEDIMENTS; LUMBRICULUS-VARIEGATUS; QUALITY CRITERIA; PORE-WATER; TOXICOKINETICS; SORPTION; SOILS AB A sample of Lake Michigan sediment was dosed with [C-14]benzo(a)pyrene ([C-14]BaP) and stored in the dark at 4 degrees C. Sets of experiments exposed Diporeia spp. for 28 days to this dosed sediment after 1 week, 6 and 13 months storage. Just prior to the exposures, the sediment was dosed again with [H-3]benzo(a)pyrene ([H-3]BaP). The accumulation of [C-14]BaP with and without [H-3]BaP was also examined after 13 months contact time to see whether the dosing with [H-3]BaP affected the bioavailability. After 1 week contact time: the uptake clearance (K-s, g sed. g(-1) h(-1)) for [C-14]BaP was about 38% lower than the K-s for [H-3]BaP. After 6 months and 13 contact time the K,for [C-14]BaP was 46% and 42% lower, respectively, than the K-s for [H-3]BaP suggesting that contact time between the compound and sediment particles may affect the bioavailability of BaP. The K-s for [C-14]BaP with and without [H-3]BaP was the same. The log K-oc, of BaP varied from 5.25 to 6.18 at different time points but then was no large difference between [H-3]BaP and [C-14]BaP. The particle size distribution of [C-14]BaP did not change during the 13 months storage and it was similar to the distribution of [H-3]BaP. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Joensuu, Dept Biol, Lab Aquat Toxicol & Ecol, FIN-80101 Joensuu, Finland. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Kukkonen, JVK (reprint author), Univ Joensuu, Dept Biol, Lab Aquat Toxicol & Ecol, POB 111, FIN-80101 Joensuu, Finland. NR 37 TC 36 Z9 37 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD JUL PY 1998 VL 42 IS 3 BP 229 EP 242 DI 10.1016/S0166-445X(97)00058-1 PG 14 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA ZW157 UT WOS:000074380800004 ER PT J AU Heinz, S Reynolds, CS Begelman, MC AF Heinz, S Reynolds, CS Begelman, MC TI X-ray signatures of evolving radio galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Perseus A); galaxies : ISM; radio continuum : galaxies; X-rays : galaxies ID COOLING FLOWS; NGC-1275; LOBES; GAS AB We present a simple model for an evolving radio galaxy as it expands into the hot, X-ray-emitting interstellar medium (ISM) of its host galaxy or similarly into the hot intracluster medium (TCM) of its host cluster. We solve the governing equations numerically on a grid of model parameters in order to present simple analytical tools for X-ray observations of the shocked shell that is pushed out by the cocoon and the associated cavity in the cluster emission. We apply these tools to the well-known example of Perseus A to show that its time-averaged kinetic luminosity probably exceeds 10(46) ergs s(-1), much larger than the estimated current power. We show how future observations can be used to extract useful source parameters such as the average kinetic power and the source age, and discuss detectability of sources at various stages of their lives. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. RP Heinz, S (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 18 TC 124 Z9 124 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5801 S ELLIS AVENUE, CHICAGO, IL 60637 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 1998 VL 501 IS 1 BP 126 EP 136 DI 10.1086/305807 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZZ946 UT WOS:000074785300012 ER PT J AU Hettler, WF AF Hettler, WF TI Abundance and size of dominant winter-immigrating fish larvae at two inlets into Pamlico Sound, North Carolina SO BRIMLEYANA LA English DT Article ID ATLANTIC MENHADEN; RECRUITMENT; ESTUARIES AB Weekly sampling for the larvae of six species of ocean-spawning, estuarine-dependent fishes was conducted from October 1994 to April 1995 inside Oregon Inlet and Ocracoke Inlet, two major inlets into Pamlico Sound, North Carolina. Atlantic menhaden, Brevoortia tyrannus, were similar in average density at both inlets; Atlantic croaker, Micropogonias undulatus, and summer flounder, Paralichthys dentatus, were more abundant at Oregon Inlet; spot, Leiostomus xanthurus, pinfish, Lagodon rhomboides, and southern flounder, P. lethostigma, were more abundant at Ocracoke Inlet. Atlantic croaker were significantly larger at Oregon Inlet at the beginning and end of the ingress season, whereas Atlantic menhaden were significantly smaller at Ocracoke Inlet at the end of the season (ca. 12 mm vs. 27 mm). Abundance data from Oregon and Ocracoke inlets were compared with abundance data collected during the same period at Beaufort Inlet and with data from a previous monthly survey conducted six years earlier at the same stations at Oregon and Ocracoke inlets. Winter temperatures were similar at both inlets, but Ocracoke Inlet was warmer during spring. Oregon Inlet was less saline than Ocracoke Inlet at every sampling event. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, Beaufort, NC 28516 USA. RP Hettler, WF (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 13 TC 3 Z9 3 U1 1 U2 3 PU NORTH CAROLINA STATE MUSEUM NATURAL SCIENCES PI RALEIGH PA C/O DIRECTOR OF RESEARCH, PO BOX 29555, RALEIGH, NC 27626-0555 USA SN 0193-4406 J9 BRIMLEYANA JI Brimleyana PD JUL PY 1998 IS 25 BP 144 EP 155 PG 12 WC Zoology SC Zoology GA 116EU UT WOS:000075711500012 ER PT J AU Moles, A AF Moles, A TI Sensitivity of ten aquatic species to long-term crude oil exposure SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID SALMON C1 Natl Marine Fisheries Serv, Auke Bay Lab, NOAA, Juneau, AK 99801 USA. RP Moles, A (reprint author), Natl Marine Fisheries Serv, Auke Bay Lab, NOAA, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 10 TC 17 Z9 17 U1 1 U2 9 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD JUL PY 1998 VL 61 IS 1 BP 102 EP 107 PG 6 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZX044 UT WOS:000074474600015 PM 9657837 ER PT J AU Warlen, SM Tester, PA Colby, DR AF Warlen, SM Tester, PA Colby, DR TI Recruitment of larval fishes into a North Carolina estuary during a bloom of the red tide dinoflagellate, Gymnodinium breve SO BULLETIN OF MARINE SCIENCE LA English DT Article ID LEIOSTOMUS-XANTHURUS AB An unprecedented bloom of the toxic dinoflagellate Gymnodinium breve in coastal waters of North Carolina occurred during year three (fall-winter 1987-1988) of an eight-year larval fish study. This event was the basis for examining the possible effects of red tide on the estuarine recruitment of nine species of larval fishes. Densities of larvae for 1987-1988 were compared to their corresponding average densities for the two seasons prior to and five seasons after the red tide. Larval fish recruitment for most species over the entire 1987-1988 season was not unusually low, although two of nine species did exhibit their 8-yr minima during this time. Densities for 1987-1988 were compared with the densities averaged (by week) over the other 7 yrs and revealed three general patterns of response. Two species, Paralichthys albigutta (gulf flounder) and Citharichthys spilopterus (bay whiff) had consistently low densities throughout their normal period of recruitment, suggesting that their estuarine recruitment may have been impacted by the effects of G. breve even after the bloom ended. In contrast, Micropogonias undulatus (Atlantic croaker) and Lagodon rhomboides (pinfish) densities were generally normal, or above normal, both during the bloom and for the remainder of the larval recruitment season. Five other species (Brevoortia tyrannus, Atlantic menhaden; Paralichthys lethostigma, southern flounder; Leiostomus xanthurus, spot; Mugil cephalus, striped mullet; Myrophis punctatus, speckled worm eel) had low densities during the bloom, but increased markedly later in the season. This pattern suggested these five species suffered immediate effects when the red tide was extant, but had high recruitment success later in the season. In the first post-red tide year, six of the nine species had their highest mean catches over the first 14 wits of all 8 yrs and suggested a possible post-red tide beneficial effect on larval fish estuarine recruitment. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, Beaufort, NC 28516 USA. RP Warlen, SM (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 38 TC 11 Z9 13 U1 0 U2 1 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 1998 VL 63 IS 1 BP 83 EP 95 PG 13 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 143GV UT WOS:000077247600006 ER PT J AU Cohn, SA Mayor, SD Grund, CJ Weckwerth, TM Senff, C AF Cohn, SA Mayor, SD Grund, CJ Weckwerth, TM Senff, C TI The lidars in flat terrain (LIFT) experiment SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CONVECTIVE BOUNDARY-LAYER; VERTICAL-VELOCITY SKEWNESS; TURBULENCE STATISTICS; DOPPLER RADAR; FLUXES; PROFILES; VARIABILITY; EXTINCTION; ENOUGH AB The authors describe and present early results from the July-August 1996 Lidars in Flat Terrain (LIFT) experiment. LIFT was a boundary layer experiment that made use of recently developed Doppler, aerosol backscatter, and ozone lidars, along with radars and surface instrumentation, to study the structure and evolution of the convective boundary layer over the very flat terrain of central Illinois. Scientific goals include measurement of fluxes of heat, moisture, and momentum; vertical velocity statistics; study of entrainment and boundary layer height; and observation of organized coherent structures. The data collected will also be used to evaluate the performance of these new lidars and compare measurements of velocity and boundary layer height to those obtained from nearby radar wind profilers. LIFT was a companion to the Flatland96 experiment, described by Angevine et al. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Boulder, CO USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Cohn, SA (reprint author), Natl Ctr Atmospher Res, Pob 3000, Boulder, CO 80307 USA. EM cohn@ucar.edu RI Senff, Christoph/I-2592-2013 NR 54 TC 31 Z9 32 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUL PY 1998 VL 79 IS 7 BP 1329 EP 1343 DI 10.1175/1520-0477(1998)079<1329:TLIFTL>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 101XC UT WOS:000074892600003 ER PT J AU Diak, GR Anderson, MD Bland, WL Norman, JM Mecikalski, JM Aune, RM AF Diak, GR Anderson, MD Bland, WL Norman, JM Mecikalski, JM Aune, RM TI Agricultural management decision aids driven by real-time satellite data SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID EARLY BLIGHT; SURFACE; INSOLATION; RADIATION; GOES-8 AB In a NASA-sponsored program entitled "Use of Earth and Space Science Data Over the Internet" scientists at the University of Wisconsin-Madison have developed a suite of products for agriculture that are based in satellite and conventional observations, as well as state-of-the art forecast models of the atmosphere and soil-canopy environments. These products include an irrigation scheduling product based in satellite estimates of daily solar energy, a frost protection product that relies on prediction models and satellite estimates of clouds, and a product for the prediction of foliar disease that is based in satellite net radiation, rainfall measured by NEXRAD, and a detailed model of the soil-canopy environment. During the growing season, the first two products are available in near-real time on the Internet. The last product involving foliar disease depends on a decision support system named WISDOM developed by the University of Wisconsin-Extension, which resides locally on growers' home computers. Growers interface WISDOM with a server to obtain the rainfall, meteorological data, surface radiation inputs, and canopy model output required by WISDOM for the blight models. C1 Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Ctr Space Sci & Engn, Madison, WI 53706 USA. Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. NOAA, Adv Satellite Prod Project, Madison, WI USA. RP Diak, GR (reprint author), Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Ctr Space Sci & Engn, 1225 W Dayton St, Madison, WI 53706 USA. RI Anderson, Martha/C-1720-2015; Aune, Robert/F-5572-2010 OI Anderson, Martha/0000-0003-0748-5525; Aune, Robert/0000-0002-7778-2739 NR 23 TC 38 Z9 38 U1 3 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUL PY 1998 VL 79 IS 7 BP 1345 EP 1355 DI 10.1175/1520-0477(1998)079<1345:AMDADB>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 101XC UT WOS:000074892600004 ER PT J AU Hamilton, K AF Hamilton, K TI Observations of tropical stratospheric winds before World War II SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID QUASI-BIENNIAL OSCILLATION; OZONE; CIRCULATION; QBO AB This paper discusses observations of the winds in the tropical stratosphere taken before the advent of regular operational balloon soundings in this region. These observations are at least broadly consistent with modem measurements, in the sense that they show that the winds in the tropical stratosphere have been undergoing some strong interannual variations over the last century. However, the available data appear to be too sparse to construct a detailed chronology of the quasi-biennial oscillation before about 1950. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Hamilton, K (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. EM kph@gfdl.gov NR 31 TC 9 Z9 10 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUL PY 1998 VL 79 IS 7 BP 1367 EP 1371 DI 10.1175/1520-0477(1998)079<1367:OOTSWB>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 101XC UT WOS:000074892600006 ER PT J AU Mahon, R Brown, SK Zwanenburg, KCT Atkinson, DB Buja, KR Claflin, L Howell, GD Monaco, ME O'Boyle, RN Sinclair, M AF Mahon, R Brown, SK Zwanenburg, KCT Atkinson, DB Buja, KR Claflin, L Howell, GD Monaco, ME O'Boyle, RN Sinclair, M TI Assemblages and biogeography of demersal fishes of the east coast of North America SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID CONTINENTAL-SHELF; ATLANTIC; COMMUNITY AB This study describes and maps demersal fish assemblages for the east coast of North America from Cape Hatteras, North Carolina, to Cape Chidley: Labrador, evaluates evidence for interannual shifts in assemblage distribution, and examines the relationship of the assemblages to accepted biogeographical boundaries. Demersal trawl survey data collected from 1975 to 1994 were analyzed. Visual classification of distribution maps for the 108 most abundant demersal species revealed nine species groups, based on both geography and depth distribution. Eighteen assemblage groups were identified using principal components analysis (PCA) and mapped. Assemblage groups were also identified by cluster analysis. Fish assemblages identified by both methods were spatially coherent. Assemblage distribution patterns were not consistent with accepted biogeographical boundaries. The PCA explained only 56.3% of the variance in distribution of the species, indicating that the assemblages should be interpreted as indeterminate, potentially adaptable entities rather than as rigid ecological constructs. Assemblages were persistent in composition through time but appeared to shift, in location. The apparent looseness of the assemblages and their persistence through time in spite of severe impacts from fishing suggest that single-species management approaches may not be entirely inappropriate for the major groundfish species in the study area. C1 Bedford Inst Oceanog, Marine Fish Div, Dept Fisheries & Oceans, Dartmouth, NS B2Y 4A2, Canada. Fisheries & Environm Consulting, St James, Barbados. Natl Ocean & Atmospher Adm, Off Ocean Resources Conservat & Assessment, Strateg Environm Assessments Div, Silver Spring, MD 20910 USA. NW Atlantic Fisheries Ctr, Dept Fisheries & Oceans, St Johns, NF A1C 5X1, Canada. Environm Canada, Dartmouth, NS B2Y 2N6, Canada. RP Zwanenburg, KCT (reprint author), Bedford Inst Oceanog, Marine Fish Div, Dept Fisheries & Oceans, Dartmouth, NS B2Y 4A2, Canada. NR 42 TC 82 Z9 88 U1 0 U2 11 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD JUL PY 1998 VL 55 IS 7 BP 1704 EP 1738 DI 10.1139/cjfas-55-7-1704 PG 35 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 124HL UT WOS:000076176300016 ER PT J AU Colwell, R Epstein, P Gubler, D Hall, M Reiter, P Shukla, J Sprigg, W Takafuji, E Trtanj, J AF Colwell, R Epstein, P Gubler, D Hall, M Reiter, P Shukla, J Sprigg, W Takafuji, E Trtanj, J TI Global climate change and infectious diseases SO EMERGING INFECTIOUS DISEASES LA English DT Article; Proceedings Paper CT International Conference on Emerging Infectious Diseases CY MAR 08-11, 1998 CL ATLANTA, GEORGIA SP Ctr Dis Control & Prevent, Council State & Terr Epidemiologists, Amer Soc Microbiol, Natl Fdn CDC, Alliance Prudent Use Antibiot, Amer Acad Pediat, Amer Assoc Blood Banks, Amer Assoc Hlth Plans, Amer Canc Soc, Amer Coll Prevent Med, Amer Hosp Assoc, Amer Med Assoc, Amer Mosquito Control Assoc, Amer Publ Hlth Assoc, Amer Sexually Transmitted Dis Assoc, Amer Soc Clin Pathologists, Amer Soc Trop Med & Hyg, Amer Vet Med Assoc, Assoc Amer Vet Med Coll, Assoc Sch Publ Hlth, Assoc State & Terr Directors Hlth Promot & Publ Hlth Educ, Assoc State & Terr Hlth Officials, Assoc State & Terr Publ Hlth Lab Directors, Assoc Teachers Prevent Med, Burroughs Wellcome Fund, Emory Univ, Sch Med, Fogarty Int Ctr, US FDA, Indian Hlth Serv, Infect Dis Soc Amer, Int Life Sci Inst, Int Soc Infect Dis, Int Soc Travel Med, Int Union Hlth Promot & Educ, Int Union Microbiol Soc, Minor Hlth Profess Fdn, Morehouse Sch Med, NASA, Natl Assoc City & County Hlth Officials, Natl Assoc State Publ Hlth Vetinarians, Natl Council Int Hlth, Natl Fdn Infect Dis, Natl Hispan Med Assoc, NIAID, Natl Med Assoc, NOAA, Off Sci & Technol Policy, Pan Amer Hlth Org, Emory Univ, Rollins Sch Publ Hlth, Soc Healthcare Epidemiol Amer, Soc Occupat & Environm Hlth, Soc Publ Hlth Educ, Carter Ctr, Henry J Kaiser Family Fdn, HMO Grp, Robert Wood Johnson Fdn, Rockefeller Fdn, World Bank, Us Agcy Int Dev, USDA, US Dept Def, US Dept State, US Dept Justice, US Dept Vet Affairs, US EPA, WHO C1 Univ Maryland, Inst Biotechnol, College Pk, MD 20742 USA. Harvard Univ, Sch Med, Boston, MA USA. Ctr Dis Control & Prevent, Atlanta, GA USA. Natl Ocean & Atmospher Adm, Washington, DC USA. Inst Global Environm & Soc Inc, Calverton, MD USA. Natl Acad Sci, Washington, DC 20418 USA. Walter Reed Army Med Ctr, Walter Reed Army Inst Res, Washington, DC 20307 USA. RP Colwell, R (reprint author), Univ Maryland, Inst Biotechnol, College Pk, MD 20742 USA. NR 1 TC 14 Z9 14 U1 0 U2 7 PU CENTER DISEASE CONTROL PI ATLANTA PA ATLANTA, GA 30333 USA SN 1080-6040 J9 EMERG INFECT DIS JI Emerg. Infect. Dis PD JUL-SEP PY 1998 VL 4 IS 3 BP 451 EP 452 PG 2 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA 111JP UT WOS:000075433800027 PM 9716968 ER PT J AU Sklar, FH Browder, JA AF Sklar, FH Browder, JA TI Coastal environmental impacts brought about by alterations to freshwater flow in the Gulf of Mexico SO ENVIRONMENTAL MANAGEMENT LA English DT Review DE resource management; landscape impacts; freshwater discharge; coastal; ecosystem models; coastal wetlands ID MISSISSIPPI RIVER PLUME; FLORIDA BAY; ESTUARINE VARIABILITY; SPARTINA-PATENS; NUTRIENT INPUTS; CANAL IMPACTS; WATER-INFLOW; LOUISIANA; SALINITY; WETLAND AB Freshwater inflow is one of the most influential landscape processes affecting community structure and function in lagoons, estuaries, and deltas of the world; nevertheless there are few reviews of coastal impacts associated with altered freshwater inputs. A conceptual model of the possible influences of freshwater inflows on biogeochemical and trophic interactions was used to structure this review, evaluate dominant effects, and discuss tools for coastal management. Studies in the Gulf of Mexico were used to exemplify problems commonly encountered by coastal zone managers and scientists around the world. Landscape alteration, impacting the timing and volume of freshwater inflow, was found to be the most common stress on estuarine systems. Poorly planned upstream landscape alterations can impact wetland and open-water salinity patterns, nutrients, sediment fertility, bottom topography, dissolved oxygen, and concentrations of xenobiotics. These, in turn, influence productivity, structure, and behavior of coastal plant and animal populations. Common biogeochemical impacts include excessive stratification, eutrophication, sediment deprivation, hypoxia, and contamination. Common biological impacts include reduction in livable habitats, promotion of "exotic" species, and decreased diversity. New multiobjective statistical models and dynamic landscape simulations, used to conduct policy-relevant experiments and integrate a wide variety of coastal data for freshwater inflow management, assume that optimum estuarine productivity and diversity is found somewhere between the stress associated with altered freshwater flow and the subsidy associated with natural flow. These models attempt to maximize the area of spatial overlap where favorable dynamic substrates, such as salinity, coincide with favorable fixed substrates, such as bottom topography. Based upon this principle of spatial overlap, a statistical performance model demonstrates how population vitality measurements (growth, survival, and reproduction) can be used to define sediment, freshwater, and nutrient loading limits. Similarly, a spatially articulate landscape simulation model demonstrates how cumulative impacts and ecosystem processes can be predicted as a function of changes in freshwater, sediment, and nutrient inflows. C1 S Florida Water Management Dist, Everglades Syst Res Div, W Palm Beach, FL 33416 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. RP Sklar, FH (reprint author), S Florida Water Management Dist, Everglades Syst Res Div, W Palm Beach, FL 33416 USA. NR 121 TC 132 Z9 136 U1 6 U2 55 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0364-152X EI 1432-1009 J9 ENVIRON MANAGE JI Environ. Manage. PD JUL-AUG PY 1998 VL 22 IS 4 BP 547 EP 562 DI 10.1007/s002679900127 PG 16 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZQ408 UT WOS:000073858200007 ER PT J AU Simiu, E Heckert, NA AF Simiu, E Heckert, NA TI Ultimate wind loads and direction effects in non-hurricane and hurricane-prone regions SO ENVIRONMETRICS LA English DT Article DE building technology; climatology; extreme value statistics; structural engineering; wind speeds AB We use 'peaks over threshold' approach to estimate extreme wind loads calculated by taking into account the directional dependence of both the aerodynamic coefficients and the extreme wind climate. Our interest is focused primarily on ultimate wind loads, that is, loads that are sufficiently large to cause member failure. For non-hurricane regions (1) we comment on issues raised by the fact that directional data published by the National Weather Service are incomplete, and (2) note that, owing to the relatively small sizes of the data samples, results on directional effects for mean recurrence intervals longer than a few hundred years are inconclusive. For hurricane-prone regions we show that, on average, the common practice of disregarding wind directionality effects is conservative for 50-year wind loads. However, according to our results, the degree of conservatism decreases as the mean recurrence interval increases. While individual estimates of speeds with very long mean recurrence intervals are unreliable, statistics based on estimates obtained from large numbers of records can provide useful indications of average trends and suggest that, for mean recurrence intervals associated with ultimate wind loads, the favorable effect of wind directionality tends to be marginal. (C) 1998 John Wiley & Sons, Ltd. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NIST, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Simiu, E (reprint author), NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 15 TC 11 Z9 12 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1180-4009 J9 ENVIRONMETRICS JI Environmetrics PD JUL-AUG PY 1998 VL 9 IS 4 BP 433 EP 444 DI 10.1002/(SICI)1099-095X(199807/08)9:4<433::AID-ENV313>3.0.CO;2-Q PG 12 WC Environmental Sciences; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Environmental Sciences & Ecology; Mathematics GA 107CF UT WOS:000075188200006 ER PT J AU Ault, JS Bohnsack, JA Meester, GA AF Ault, JS Bohnsack, JA Meester, GA TI A retrospective (1979-1996) multispecies assessment of coral reef fish stocks in the Florida Keys SO FISHERY BULLETIN LA English DT Article ID BIOMASS AB A baseline assessment of 35 economically and ecologically important Florida Keys reef fish stocks is provided by using a systems approach that integrates sampling, statistics, and mathematical modeling. Quantitative fishery-independent data from reef fish visual surveys conducted by SCUBA divers from 1979 to 1996 were used to develop estimates of population abundance, assemblage composition, and stock structures in relation to key physical and habitat factors. Exploitation effects were assessed with a new length-based algorithm that calculates total mortality rates from estimates of "average length of fish in the exploitable phase of the stock." These estimates were highly correlated for two statistically independent data sources on reef fish: fishery-independent diver observations and fishery-dependent head boat catches. We developed a reef fish equilibrium exploitation fishery simulation (REEFS) model and used estimates of fishing mortality to assess yield-per-recruit in relation to fishing intensity and gear selectivity and to assess spawning potential ratio (SPR) in relation to U.S. federal "overfishing" standards. Our analyses show that 13 of 16 groupers (Epinephelinae), 7 of 13 snappers (Lutjanidae), one wrasse (Labridae), and 2 of 5 grunts (Haemulidae) are below the 30% SPR overfishing minimum. Some stocks appear to have been chronically overfished since the late 1970s. The Florida Keys reef fishery exhibits classic "serial overfishing" in which the largest, most desirable, and vulnerable species are depleted by fishing. Rapid growth of the barracuda population (Sphyraenidae) during the same period suggests that fishing has contributed to substantial changes in community structure and dynamics. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. RP Ault, JS (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Ault, Jerald/A-5241-2008 OI Ault, Jerald/0000-0001-9657-8007 NR 55 TC 104 Z9 111 U1 3 U2 21 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 395 EP 414 PG 20 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600001 ER PT J AU Collins, LA Johnson, AG Koenig, CC Baker, MS AF Collins, LA Johnson, AG Koenig, CC Baker, MS TI Reproductive patterns, sex ratio, and fecundity in gag, Mycteroperca microlepis (Serranidae), a protogynous grouper from the northeastern Gulf of Mexico SO FISHERY BULLETIN LA English DT Article ID NORTHERN GULF; OF-MEXICO; EPINEPHELUS-GUTTATUS; OVARIAN DEVELOPMENT; SPAWNING FREQUENCY; EASTERN GULF; BLACK DRUM; RED HIND; BIOLOGY; PISCES AB We determined sex ratio, spawning season, batch fecundity, spawning frequency, and annual fecundity for gag (Serranidae: Mycteroperca microlepis), a protogynous hermaphrodite. Gag were randomly sampled from 1991 through 1993 (n=1398) and selectively sampled with a bias towards heavily pigmented fish in 1994 (n=648). All samples were taken from commercial and recreational fisheries in the northeastern Gulf of Mexico. Sex ratio was 49 females: 1 male for the 1991-93 samples. Heavily pigmented gag (n=62), commonly thought to be males, were collected from waters >41.0 m during all months except January and March. Of these, 60 were histologically sexed and found to be 5.0% female, 3.3% possibly early transitional male, and 91.7% male. Indeterminate spawning generally occurred from February through April in water depths >30.5 m. Hydrated oocytes were homogeneously distributed in hydrated ovaries. Shortest length and youngest age at spawning were 577 mm total length (TL) and 3 years for females, and 981 mm TL and 8 years for males. The highest batch fecundity (865,295 hydrated oocytes) occurred in an 8-year-old, 1038-mm-TL gag. Batch fecundity had a significant (alpha=0.01) positive correlation with TL, gutted body weight, and age but was most strongly correlated with TL. Average annual spawning frequency ranged from 8 to 27 for 2- to 9-year-old fish, varying significantly by year (P<0.05) and among years and age classes (P<0.02). Annual fecundity estimates ranged from 0.065 to 61.4 million and correlated well with age. C1 NOAA, Natl Marine Fisheries Serv, Panama City Lab, Panama City, FL 32408 USA. RP Collins, LA (reprint author), NOAA, Natl Marine Fisheries Serv, Panama City Lab, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 33 TC 39 Z9 41 U1 2 U2 11 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 415 EP 427 PG 13 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600002 ER PT J AU Kimura, DK Shimada, AM Shaw, FR AF Kimura, DK Shimada, AM Shaw, FR TI Stock structure and movement of tagged sablefish, Anoplopoma fimbria, in offshore northeast Pacific waters and the effects of El Nino Southern Oscillation on migration and growth SO FISHERY BULLETIN LA English DT Article ID MERLUCCIUS-PRODUCTUS; CENTRAL CALIFORNIA; FECUNDITY; DYNAMICS; OREGON AB Sablefish in the northeast Pacific are found in commercial quantities from the Baring Sea, the Aleutian Islands, throughout the Gulf of Alaska, and south along the west coast of Canada and the U.S. to Baja California. Tag-recovery data support a two-population hypothesis throughout the North American range: an Alaska population ranging from the Bering Sea, including the Aleutian Islands and extending down through the Gulf of Alaska to northwest Vancouver Island, Canada; and a west coast population extending from southwest Vancouver Island to Baja California. Tag recoveries indicate that these two populations mix off southwest Vancouver Island and northwest Washington, and to a lesser extent off southern Washington and Oregon. Alaska sablefish, which commonly migrate over 500 n mi, are more mobile than west coast sablefish. Tag recoveries for sablefish tagged in Alaska have shown strong mutual exchanges between nearly all areas. In contrast, west coast sablefish have shown far less migratory behavior. Tagging data with respect to bathymetry are difficult to interpret in both regions owing to the fact that tagging and recovery effort do not cover the full bathymetric range of adults. Results of analysis of tag-recapture growth data were consistent with patterns observed for several other pelagic and demersal species. That is, El Nino-Southern Ocean Oscillation events appeared to retard the growth of sablefish along the west coast and to enhance growth of Alaska sablefish. The timing of recoveries from sablefish tagged off Alaska and recovered off southwest Vancouver Island and Washington-Oregon suggests that movement south correlates positively with strong upwelling in this southern area. Although sablefish trap-index surveys show a north to south cline in the percentage of large sablefish (>60 cm, and possibly of Alaska origin) sampled in length frequencies along the west coast, we were unable to correlate annual fluctuations in these percentages with upwelling strength. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Kimura, DK (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM Dan.Kimura@noaa.gov NR 49 TC 29 Z9 31 U1 0 U2 6 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 462 EP 481 PG 20 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600006 ER PT J AU Lowe, SA Van Doornik, DM Winans, GA AF Lowe, SA Van Doornik, DM Winans, GA TI Geographic variation in genetic and growth patterns of Atka mackerel, Pleurogrammus monopterygius (Hexagrammidae), in the Aleutian archipelago SO FISHERY BULLETIN LA English DT Article AB Atka mackerel, Pleurogrammus monopterygius, growth data differed significantly by area for length and weight characteristics, suggesting that local aggregations of this species develop differential growth patterns. We analyzed length-at-age and weight-length growth patterns from over 500 fish and 37 protein-coding gene loci to determine the relation among Atka mackerel stocks in the Aleutian Islands. However, the potential stock delineations based on the growth patterns were not supported by the genetic data. Atka mackerel showed a high degree of genetic variability. Variation was detected at 30 of 37 loci; 14 of the 30 loci were variable at the P-0.95 level. Average heterozygosity for 329 specimens was 0.137, an unusually high value for a marine fish. Between-sample variation among samples was extremely low (F-ST=0.004), suggesting considerable gene flow throughout the range represented by the samples. On the basis of the genetic data, we cannot reject the null hypothesis that our samples came from a single genetically homogenous population of Atka mackerel. We presume that gene flow occurs throughout the population through the dispersal of pelagic larvae and juveniles. We conclude that despite genetic homogenization, phenotypic variation in Atka mackerel adult life history stages warrants consideration by fishery managers. C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Lowe, SA (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE,BIN C15700, Seattle, WA 98115 USA. NR 27 TC 12 Z9 16 U1 1 U2 4 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 502 EP 515 PG 14 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600009 ER PT J AU Munro, PT AF Munro, PT TI A decision rule based on the mean square error for correcting relative fishing power differences in trawl survey data SO FISHERY BULLETIN LA English DT Article ID ABUNDANCE; ESTIMATORS; MODELS AB Some combinations of trawler, trawl, and crew catch fish better than others. Systematic error enters catch per unit of effort (CPUE) data from trawl surveys through such relative differences in efficiency among sampling instruments. Correcting relative fishing power differences can remove bias due to systematic error but may also increase the variance of the mean CPUE estimate. As a result, the overall error of the estimate may actually become worse, even when the fishing power difference is statistically significant. A decision rule specified by the mean square error (MSE) of the mean CPUE estimate avoids this mistake: namely a correction that reduces the error in the mean CPUE estimate would be applied, a correction that increases the error would not be applied. I describe and demonstrate an algorithm, based on minimizing the MSE, for deciding to correct a fishing power difference. The strategy requires that a probability density function exist that models the CPUE data reasonably well. C1 NOAA, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, Seattle, WA 98115 USA. RP Munro, PT (reprint author), NOAA, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, 7600 Sand Point Way NE,BIN C-15700, Seattle, WA 98115 USA. NR 26 TC 7 Z9 9 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 538 EP 546 PG 9 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600012 ER PT J AU Nichol, DG AF Nichol, DG TI Annual and between-sex variability of yellowfin sole, Pleuronectes asper, spring-summer distributions in the eastern Bering Sea SO FISHERY BULLETIN LA English DT Article AB Annual and between-sex variations in yellowfin sole, Pleuronectes asper, distributions in the eastern Bering Sea during spring and summer were examined by analyzing research survey data, including a standard 15-year time series from 1982 to 1996, as well as exploratory nearshore samples. Yellowfin sole were most concentrated nearshore; abundance gradually decreased with increasing bottom depth to trace numbers beyond 100 m. Male yellowfin sole were distributed nearer to shore than females in all years.. Proportions of males (no. males/no, both sexes), therefore, increased nearshore with decreasing bottom depth. Males outnumbered females by two to one in waters less than 30 m deep. Yellowfin sole during 1982-84 were distributed in deeper waters than during 1985-96. The shallower distributions after 1984 were attributed to greater percentages of mature fish that reside in nearshore spawning areas (< 30 m) during spring-summer. High biomass estimates (>3 million metric tons) during 1982-84 were attributed in part to increased availability of yellowfin sole within the standard survey area. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, Seattle, WA 98115 USA. RP Nichol, DG (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, 7600 Sand Point Way NE,BIN C15700, Seattle, WA 98115 USA. NR 21 TC 12 Z9 12 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 547 EP 561 PG 15 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600013 ER PT J AU Schmid, JR AF Schmid, JR TI Marine turtle populations on the west-central coast of Florida: Results of tagging studies at the Cedar Keys, Florida, 1986-1995 SO FISHERY BULLETIN LA English DT Article ID IMMATURE GREEN TURTLES; CHELONIA-MYDAS; GROWTH-RATES; LEPIDOCHELYS-KEMPII; CARETTA-CARETTA; FEEDING ECOLOGY; SEA-TURTLES; MOVEMENTS; PATTERNS; WATERS AB Large-mesh tangle nets were used to collect marine turtles in Waccasassa Bay, near the Cedar Keys, Florida, from June 1986 to October 1995. Tagging records were analyzed to determine the species composition, population structure, and seasonal occurrence of Kemp's ridley, Lepidochelys kempii, loggerhead, Caretta caretta, and green, Chelonia mydas, turtles. Additional information on local movements, morphometrics, growth, population estimation, and diet was provided for Kemp's ridley turtles. Subadult green turtles dominated the catch on the seagrass shoals of Waccasassa Reefs. Subadult Kemp's ridley turtles and, to a lesser degree, subadult and adult loggerhead turtles were primarily captured near the oyster bars of Corrigan Reef. Marine turtles were caught in these nearshore waters from April to November. Recaptures indicate that some Kemp's ridley turtles remain in the vicinity of Corrigan Reef during their seasonal occurrence and return to this foraging area annually. Seasonal and annual size distributions of Kemp's ridley turtles were investigated and regression equations were developed for carapace morphometrics. Carapace growth averaged 4-5 cm/yr for Kemp's ridley turtles, but growth analyses were confounded by the extrapolation of annual estimates from short-term recaptures. Population estimates for the Kemp's ridley mark-recapture data indicated a mean annual population size of 159 turtles at Corrigan Reef with presumably high rates of immigration and emigration by larger subadult turtles. Examination of fecal samples indicated that crabs were the primary food items of Kemp's ridley turtles captured near oyster bars. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. Univ Florida, Archie Carr Ctr Sea Turtle Res, Gainesville, FL 32611 USA. RP Schmid, JR (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 75 Virginia Beach Dr, Miami, FL 33149 USA. EM jeffrey.schmid@noaa.gcv NR 59 TC 17 Z9 24 U1 0 U2 8 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 589 EP 602 PG 14 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600016 ER PT J AU Bejda, AJ Phelan, BA AF Bejda, AJ Phelan, BA TI Can scales be used to sex winter flounder, Pleuronectes americanus? SO FISHERY BULLETIN LA English DT Article C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Bejda, AJ (reprint author), NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1998 VL 96 IS 3 BP 621 EP 623 PG 3 WC Fisheries SC Fisheries GA 106ZP UT WOS:000075181600019 ER PT J AU Molinari, RL Fine, RA Wilson, WD Curry, RG Abell, J McCartney, MS AF Molinari, RL Fine, RA Wilson, WD Curry, RG Abell, J McCartney, MS TI The arrival of recently formed Labrador Sea Water in the Deep Western Boundary Current at 26.5 degrees N SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID THERMOHALINE CIRCULATION; NORTH-ATLANTIC AB The Deep Western Boundary Current (DWBC) of the North Atlantic is a principal conduit between the formation region for Labrador Sea Water (LSW) and the oceanic interior to the south. Time series (1985-1997) of hydrographic properties obtained in the DWBC at 26.5 degrees N show that prior to 1994, temperature, salinity, and transient tracer properties within the LSW density range showed little indication of recently formed parcels. Properties characteristic of a newer version of LSW (cooler, fresher, and higher tracer concentrations) were observed beginning in 1994 and continuing through 1997. Longer time series of temperature and salinity, developed from a regional data base, show both the 1994 and a 1980-1981 event in the Abaco region. Both events are consistent with anomalies in the Labrador Sea that occurred some 10 years earlier. The 10-year transit time from the Labrador Sea to 26.5 degrees N is less than the 18-year transit time inferred from earlier studies. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Phys Oceanog Div, Miami, FL 33149 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. RP Molinari, RL (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Phys Oceanog Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI McCartney, Michael/A-3922-2009 NR 16 TC 70 Z9 70 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1998 VL 25 IS 13 BP 2249 EP 2252 DI 10.1029/98GL01853 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZZ145 UT WOS:000074700200001 ER PT J AU Feely, RA Trefry, JH Lebon, GT German, CR AF Feely, RA Trefry, JH Lebon, GT German, CR TI The relationship between P/Fe and V/Fe ratios in hydrothermal precipitates and dissolved phosphate in seawater SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MID-ATLANTIC RIDGE; EAST PACIFIC RISE; FUCA RIDGE; PHOSPHORUS; SEDIMENTS; VANADIUM; GEOCHEMISTRY; PLUMES; OCEAN; JUAN AB A strong positive relationship between the molar P/Fe ratio in fresh hydrothermal Fe ferrihydrite precipitates and seawater-dissolved phosphate has been demonstrated using samples from the Atlantic and Pacific Oceans. We ascribe this relationship to scavenging of dissolved phosphate from seawater during the formation of hydrothermal Fe-rich particles above hydrothermal vents. In contrast, molar V/Fe ratios in hydrothermal particles are inversely correlated with dissolved phosphate. These results indicate that inter-ocean variations in dissolved phosphate control the P/Fe and V/Fe ratios in hydrothermal Fe precipitates, one of the precursors of metalliferous sediment. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Florida Inst Technol, Dept Oceanog, Melbourne, FL 32901 USA. Southampton Oceanog Ctr, Southampton SO14 3ZH, Hants, England. RP Feely, RA (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM feely@pmel.noaa.gov; jtrefry@fit.edu; lebon@pmel.noaa.gov; cge@soc.soton.ac.uk OI Trefry, John/0000-0002-8451-5524 NR 25 TC 46 Z9 48 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1998 VL 25 IS 13 BP 2253 EP 2256 DI 10.1029/98GL01546 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZZ145 UT WOS:000074700200002 ER PT J AU Baranyi, T Ludmany, A Coffey, H AF Baranyi, T Ludmany, A Coffey, H TI 22 Year solar modulation of Earth's northern hemisphere temperatures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CYCLE; WIND AB As reported earlier, solar particle events originating from the Sun's polar regions affect the Earth's troyosphere in a way that is opposite to solar particle events from the Sun's equatorial regions. When the Sun's magnetic field reverses every 11 years, the tropospheric response also reverses. These results are based on European temperature data. The present extension (712 northern stations) to a more worldwide coverage shows that this complex behavior is reversed oil the western side of the Earth's northern hemisphere. The border separating the two regimes (East vs. West) lies close to the meridian crossing the magnetic pole. These results imply that the physical mechanism linking the solar and tropospheric changes may be sensitive to the specific spatial conditions and magnetic polarity distributions. C1 NOAA, NESDIS, NGDC, Solar Terr Phys Div EGC2, Boulder, CO 80303 USA. Hungarian Acad Sci, Heliophys Observ, H-4010 Debrecen, Hungary. RP Baranyi, T (reprint author), NOAA, NESDIS, NGDC, Solar Terr Phys Div EGC2, 325 Broadway, Boulder, CO 80303 USA. NR 17 TC 13 Z9 13 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1998 VL 25 IS 13 BP 2269 EP 2272 DI 10.1029/98GL01798 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZZ145 UT WOS:000074700200006 ER PT J AU Hofmann, DJ Stone, RS Wood, ME Deshler, T Harris, JM AF Hofmann, DJ Stone, RS Wood, ME Deshler, T Harris, JM TI An analysis of 25 years of balloonborne aerosol data in search of a signature of the subsonic commercial aircraft fleet SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EMISSIONS AB The University of Wyoming balloonborne condensation nuclei (CN) record for 1973-1997 was analyzed to determine possible effects of commercial aircraft on the 8.6 - 12.7 km altitude range of the atmosphere, which includes the primary commercial airlanes between 29 and 41 kft. Thin layers of highly concentrated CN are often observed in this region of the atmosphere. Generally, aircraft night information is not available for past balloon soundings making it impossible to ascribe a source to any specific observed CN layers. However, a CN layer observed in March 1997 was traced to a particular aircraft thus supporting the hypothesis that at least some of the observed layers are contrail remnants. Using the Laramie data set, a method was developed to quantify the enhancement in CN concentration induced by aircraft in comparison with natural background levels. We estimate conservatively that the contribution of the commercial aircraft fleet in the vicinity of Laramie, Wyoming, averaged over the period of record, amounts to about 10% of the background CN concentration The frequency of occurrence of the CN layers approximately doubled from 1980 to 1992. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Hofmann, DJ (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 17 Z9 17 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1998 VL 25 IS 13 BP 2433 EP 2436 DI 10.1029/98GL01776 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZZ145 UT WOS:000074700200048 ER PT J AU Chen, Y Suehle, JS Shen, CC Bernstein, JB Messick, C Chaparala, P AF Chen, Y Suehle, JS Shen, CC Bernstein, JB Messick, C Chaparala, P TI A new technique for determining long-term TDDB acceleration parameters of thin gate oxides SO IEEE ELECTRON DEVICE LETTERS LA English DT Article AB A new technique, the dual voltage versus time curve (V-t) integration technique, is presented as a much faster method to obtain time-dependent dielectric breakdown (TDDB) acceleration parameters (alpha and gamma) of ultrathin gate oxides compared to conventional long-term constant voltage stress tests. The technique uses V-t curves measured during highly accelerated constant or ramped current injection breakdown tests. It is demonstrated that the technique yields acceleration parameters that are statistically identical to values obtained from long-term constant voltage TDDB tests. In contrast to traditional TDDB tests, the proposed technique requires over an order of magnitude less testing time, a smaller sample size, and can be used during production monitoring. C1 Univ Maryland, Ctr Reliabil Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. Fairchild Semicond, W Jordan, UT 84088 USA. Natl Semicond Corp, Santa Clara, CA 95052 USA. RP Chen, Y (reprint author), Univ Maryland, Ctr Reliabil Engn, College Pk, MD 20742 USA. NR 10 TC 13 Z9 13 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD JUL PY 1998 VL 19 IS 7 BP 219 EP 221 DI 10.1109/55.701422 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA ZW033 UT WOS:000074366900003 ER PT J AU Wielicki, BA Barkstrom, BR Baum, BA Charlock, TP Green, RN Kratz, DP Lee, RB Minnis, P Smith, GL Wong, TM Young, DF Cess, RD Coakley, JA Crommelynck, DAH Donner, L Kandel, R King, MD Miller, AJ Ramanathan, V Randall, DA Stowe, LL Welch, RM AF Wielicki, BA Barkstrom, BR Baum, BA Charlock, TP Green, RN Kratz, DP Lee, RB Minnis, P Smith, GL Wong, TM Young, DF Cess, RD Coakley, JA Crommelynck, DAH Donner, L Kandel, R King, MD Miller, AJ Ramanathan, V Randall, DA Stowe, LL Welch, RM TI Clouds and the Earth's Radiant Energy System (CERES): Algorithm overview SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE algorithms; clouds; meteorology; radiation monitoring ID RADIATION BUDGET EXPERIMENT; SURFACE RADIATION; SATELLITE DATA; SOLAR-RADIATION; CIRRUS CLOUDS; CLIMATE; PARAMETERIZATION; ERBE; ABSORPTION; FLUXES AB The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS), CERES objectives include the following. 1) For climate change analysis, provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA), analyzed using the same techniques as the existing ERBE data. 2) Double the accuracy of estimates of radiative fluxes at TOA and the earth's surface; 3) Provide the first long-term global estimates of the radiative fluxes within the earth's atmosphere. 4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA, In order to accomplish these goals, CERES uses data from a combination of spaceborne instruments: CERES scanners, which are an improved version of the ERBE broadband radiometers, and collocated cloud spectral imager data on the same spacecraft. The CERES cloud and radiative flux data products should prove extremely useful in advancing the understanding of cloud-radiation interactions, particularly cloud feedback effects on the earth's radiation balance, For this reason, the CERES data should be fundamental to our ability to understand, detect, and predict global climate change, CERES results should also be very useful for studying regional climate changes associated with deforestation, desertification anthropogenic aerosols, and El Nino/Southern Oscillation events. This overview summarizes the Release 2 version of the planned CERES data products and data analysis algorithms. These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the earth's climate system. This release will produce a data processing system designed to analyze the first CERES data, planned for launch on Tropical Rainfall Measuring Mission (TRMM) in November 1997, followed by the EOS morning (EOS-AM1) platform in 1998. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. SUNY Stony Brook, Stony Brook, NY 11790 USA. Oregon State Univ, Corvallis, OR 97331 USA. Inst Royal Meteorol, B-1180 Brussels, Belgium. Natl Ocean & Atmospher Adm, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Natl Ctr Environm Predict, NWS, Washington, DC 20233 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Colorado State Univ, Ft Collins, CO 80521 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Washington, DC 20233 USA. Univ Alabama, Huntsville, AL 35807 USA. RP Wielicki, BA (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. EM b.a.wielicki@larc.nasa.gov RI King, Michael/C-7153-2011; Randall, David/E-6113-2011; Baum, Bryan/B-7670-2011; Minnis, Patrick/G-1902-2010 OI King, Michael/0000-0003-2645-7298; Randall, David/0000-0001-6935-4112; Baum, Bryan/0000-0002-7193-2767; Minnis, Patrick/0000-0002-4733-6148 NR 59 TC 160 Z9 161 U1 4 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1998 VL 36 IS 4 BP 1127 EP 1141 DI 10.1109/36.701020 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ZZ760 UT WOS:000074764400009 ER PT J AU Esaias, WE Abbott, MR Barton, I Brown, OB Campbell, JW Carder, KL Clark, DK Evans, RH Hoge, FE Gordon, HR Balch, WM Letelier, R Minnett, PJ AF Esaias, WE Abbott, MR Barton, I Brown, OB Campbell, JW Carder, KL Clark, DK Evans, RH Hoge, FE Gordon, HR Balch, WM Letelier, R Minnett, PJ TI An overview of MODIS capabilities for ocean science observations SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SEA-SURFACE TEMPERATURE; ZONE COLOR SCANNER; ATMOSPHERIC CORRECTION; NATURAL FLUORESCENCE; CHLOROPHYLL-A; PHYTOPLANKTON PIGMENTS; INFRARED MEASUREMENTS; IMAGING SPECTROMETER; RADIOMETER DATA; GLOBAL OCEAN AB The Moderate Resolution Imaging Spectroradiometer (MODIS) will add a significant new capability for investigating the 70% of the earth's surface that is covered by oceans, in addition to contributing to the continuation of a decadal scale time series necessary for climate change assessment in the oceans. Sensor capabilities of particular importance for improving the accuracy of ocean products include high SNR and high stability for narrower spectral bands, improved onboard radiometric calibration and stability monitoring, and improved science data product algorithms. Spectral bands for resolving solar-stimulated chlorophyll fluorescence and a split window in the 4-mu m region for SST will result in important new global ocean science products for biology and physics. MODIS will return full global data at 1-km resolution. The complete suite of Levels 2 and 3 ocean products is reviewed, and many areas where MODIS data are expected to make significant, new contributions to the enhanced understanding of the oceans' role in understanding climate change are discussed. In providing a highly complementary and consistent set of observations of terrestrial, atmospheric, and ocean observations, MODIS data will provide important new information on the interactions between earth's major components. C1 Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20777 USA. Oregon State Univ, Sch Oceanog, Corvallis, OR 97331 USA. CSIRO, Marine Labs, Hobart, Tas 7001, Australia. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. NASA, MPTE, Washington, DC 20546 USA. Univ S Florida, Dept Oceanog, Tampa, FL 33620 USA. NOAA, Ocean Res & Applicat Div, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Island, VA 23337 USA. Univ Miami, Dept Phys, Coral Gables, FL 33149 USA. Bigelow Lab Ocean Sci, Boothbay Harbor, ME 04575 USA. RP Esaias, WE (reprint author), Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971, Greenbelt, MD 20777 USA. EM wayne.esaias@gsfc.nasa.gov RI Letelier, Ricardo/A-6953-2009; Brown, Otis/C-7188-2015 OI Letelier, Ricardo/0000-0003-3376-4026; Brown, Otis/0000-0003-3111-1507 NR 99 TC 258 Z9 268 U1 2 U2 31 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 1998 VL 36 IS 4 BP 1250 EP 1265 DI 10.1109/36.701076 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ZZ760 UT WOS:000074764400018 ER PT J AU McMichael, RD Chen, PJ Egelhoff, WF AF McMichael, RD Chen, PJ Egelhoff, WF TI Time and temperature dependence of high thermal stability in NiO/Co/Cu/Co/M spin valves SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 7th Joint MMM-Intermag Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA ID GIANT-MAGNETORESISTANCE; CO/CU MULTILAYERS; THIN-FILMS; LOW FIELDS; INTERFACES AB The thermal stability of Cu/Co 'bottom' spin valve structures deposited on NiO has been assessed as a function of temperature, time, and cap layer compositions including Au, Ta and TaxOy Samples with 5.0 nm thick cap layers of Au showed a reduction in giant magnetoresistance (GMR) from 9.3% to 3.6% after a 0.5 hr anneals at 250 degrees C, As a function of time, the sample resistance, R(t), showed an exponential saturation with a time constant, tau, which follows an Arrhenius law, tau ro exp[Delta E/kT], with Delta E = 1.29 +/- 0.03 eV and tau(0) on the order of 10(-8) s to 10(-9) s, These parameters, which fit R(t), correlate with the time and anneal temperature dependence of GMR decay in the Au-capped spin valves. In contrast, samples with Ta or TaxOy cap layers showed good stability for 0.5 hr anneals up to 325 degrees C. Decreases in GMR from 12.7% to 3.9% following a 20 h anneal at 325 degrees C are accompanied by significant changes in the hysteresis loops which appear to be associated with the pinned layer. With a 5.0 nm Ta cap, R(t) follows a logarithmic-like time dependence characteristic of a distribution of activation energies. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP McMichael, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 15 TC 8 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 1998 VL 34 IS 4 BP 897 EP 899 DI 10.1109/20.706304 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 101CP UT WOS:000074852300025 ER PT J AU Arnold, CS Venus, D AF Arnold, CS Venus, D TI Evidence for domain-condensation near the ferromagnetic to paramagnetic transition in perpendicularly magnetized, ultrathin Fe/2 ML Ni/W(110) films SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 7th Joint MMM-Intermag Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA DE ultrathin films; perpendicular magnetism; critical phenomena; domains ID TEMPERATURE; PHASE AB Ultrathin, fee Fe/2 ML Ni(lll) films were grown on a W(110) substrate in UHV by electron beam evaporation. Fe films less than 2.2 ML thick posses a perpendicular moment that does not reorient to an in-plane easy axis below T-c, the temperature of the ferromagnetic to paramagnetic transition. The magnetic susceptibility of the films was measured as a function of temperature using the polar Kerr effect. The real part of the susceptibility is large, peaking at well above 100 SI units, and exhibits a simple exponential decay over a range of several tens of Kelvin above the temperature T-REM, where the remanent magnetization disappears. This behavior of the susceptibility is in agreement with that expected from the perpendicularly magnetized domain structure usually identified as a precursor to a spin reorientation transition. No signature of T-c, is found in the susceptibility. C1 McMaster Univ, Dept Phys, Hamilton, ON L8S 4M1, Canada. McMaster Univ, Brockhouse Inst Mat Res, Hamilton, ON L8S 4M1, Canada. RP Arnold, CS (reprint author), Natl Inst Stand & Technol, 325 Broadway,814-05, Boulder, CO 80303 USA. NR 18 TC 6 Z9 6 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 1998 VL 34 IS 4 BP 1039 EP 1041 DI 10.1109/20.706350 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 101CP UT WOS:000074852300069 ER PT J AU Porter, DG AF Porter, DG TI Analytical determination of the LLG zero-damping critical switching field SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 7th Joint MMM-Intermag Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA DE Landau-Lifshitz dynamics; Stoner-Wohlfarth model; switching field; zero damping AB Previous numerical studies based on the Landau-Lifshitz-Gilbert (LLG) equation have considered the magnetisation reversal of a uniaxial, single-domain particle due to an applied field pulse with a short rise time. When the LLG damping constant alpha < 1, these studies have observed coherent switching for applied field magnitudes below the Stoner-Wohlfarth limit. The switching field computed in these studies decreases as alpha --> 0, with apparent convergence to a limiting value. In this paper, analytic methods determine the value of the switching field in the zero-damping limit for an applied field pulse with zero rise time. The locus of normalized switching fields in parametric form is h(y) = - sin theta(cos theta - 1)/2; h(z) = -cos theta(cos theta + 1)/2; \theta\ less than or equal to 2 pi/3. A non-parametric form is also derived. One surprising implication is that magnetization reversal may be caused by an applied field with easy axis component in the same direction as the initial magnetization (h(z) > 0). C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Porter, DG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 14 Z9 15 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 1998 VL 34 IS 4 BP 1663 EP 1665 DI 10.1109/20.706649 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 101CP UT WOS:000074852300275 ER PT J AU Rizzo, ND Silva, TJ AF Rizzo, ND Silva, TJ TI Thermal relaxation in the strong-demagnetizing limit SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 7th Joint MMM-Intermag Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA DE magnetic viscosity; demagnetizing field; bit transition AB We have developed a new technique that simulates the thermal magnetization decay (magnetic viscosity) within hit transitions that have a strong demagnetizing field H-d approximately equal to the remanent coercivity of the recording medium This technique uses a vibrating-sample magnetometer to measure the viscosity while allowing the applied field to decay logarithmically at a rate consistent with the measured magnetization decay. The decaying applied field simulates the decaying H-d of a broadening bit transition. The magnetic decay measured using this technique remains logarithmic in time, bat is almost a factor of 4 smaller than that measured using a constant applied field. These results imply that the standard viscosity measurement is inappropriate when estimating the amount of thermal broadening doe to H-d within a transition. We have also developed a model of the magnetization decay in a large decaying H-d using a modified Arrhenius-Neel rate equation with a single energy barrier that has explicit dependence on the magnetization. The model predicts logarithmic magnetization decay consistent with that observed experimentally and also indicates that the viscosity measured using this technique may be a measure of the average energy barrier preventing thermal switching. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Rizzo, ND (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 9 TC 5 Z9 5 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 1998 VL 34 IS 4 BP 1857 EP 1859 DI 10.1109/20.706726 PN 1 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 101CP UT WOS:000074852300336 ER PT J AU Mansoor, A Martzloff, F AF Mansoor, A Martzloff, F TI The effect of neutral earthing practices on lightning current dispersion in a low-voltage installation SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article AB Computer modeling with the EMTP code has been applied to several configurations and earthing practices in use in various countries to show the effect of any differences in the dispersion (sharing) of a lightning stroke current among the available paths for the earth-seeking lightning current. Simplifying assumptions have been made to some details of the configurations to focus on the main difference - earthing practices. Identifying such differences provides the necessary perspective on their significance and the strong need to take them into consideration when developing international standards on surge-protective device applications. C1 Power Elect Applicat Ctr, Knoxville, TN 37932 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mansoor, A (reprint author), Power Elect Applicat Ctr, Knoxville, TN 37932 USA. NR 20 TC 8 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD JUL PY 1998 VL 13 IS 3 BP 783 EP 792 DI 10.1109/61.686975 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA ZW307 UT WOS:000074397000017 ER PT J AU Xiang, D Hsu, NN Blessing, GV AF Xiang, D Hsu, NN Blessing, GV TI Statistical error analysis of time and polarization resolved ultrasonic measurements SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID BEAM ACOUSTIC MICROSCOPE; TRANSDUCER; V(Z); WAVE AB The time and polarization resolved ultrasonic technique which we previously developed has been demonstrated to simultaneously provide measurements of the wave velocity in the coupling liquid, and the leaky surface wave and leaky longitudinal wave velocities in solid samples. To document the measurement precision associated with this technique, a statistical method is employed for the data fit and error analysis. With the help of statistical analysis, the simple ray model used to determine wave velocities in this technique is first confirmed by theoretical data which are predicted by the Green's function. Error analysis is then applied to the experimental data. The results show that this technique has a relative expanded uncertainty (equal to twice the standard deviation) of 0.03% for the wave velocity in water, and an uncertainty less than 0.2% and 2%, respectively, for the leaky surface and leaky longitudinal wave velocities in a crown glass sample. The uncertainty in the repeatability for leaky surface wave measurements is observed to be much less than the expanded uncertainty of a single measurement set. This methodology also has been applied to a set of steel samples. The results show that the expanded uncertainty for leaky surface wave velocities is less than 0.07%, enabling a correlation of the measured velocities with specific sample heat treatments. C1 Natl Inst Stand & Technol, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. RP Xiang, D (reprint author), Natl Inst Stand & Technol, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. NR 26 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD JUL PY 1998 VL 45 IS 4 BP 1006 EP 1016 DI 10.1109/58.710582 PG 11 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 107MW UT WOS:000075213900020 PM 18244255 ER PT J AU Senehi, MK Kramer, TR AF Senehi, MK Kramer, TR TI A framework for control architectures SO INTERNATIONAL JOURNAL OF COMPUTER INTEGRATED MANUFACTURING LA English DT Article ID INFORMATION-SYSTEMS ARCHITECTURE AB The development of architectures for control systems has been an active area of research for at least twenty years. This research has produced many different architectures which use different terminologies and address different issues. In order to analyse existing architectures and to determine issues that must be addressed in defining a new one, a common terminology for discussing architectures and a framework for organizing information about architectures is needed. Based upon an examination of many control architectures in the areas of computer integrated manufacturing and robotics, the authors propose a terminology for discussing control architectures and a framework for constructing control architectures. The authors have used the terminology and framework to develop a set of issues which need to be addressed when constructing a control architecture. These issues have been used to compare two architectures developed at National Institute of Standards and Technology. This paper presents the terminology, the framework, and issues related to constructing an architecture using the framework. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Senehi, MK (reprint author), Natl Inst Stand & Technol, Room B-124,Bldg 220, Gaithersburg, MD 20899 USA. NR 47 TC 5 Z9 5 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0951-192X J9 INT J COMP INTEG M JI Int. J. Comput. Integr. Manuf. PD JUL-AUG PY 1998 VL 11 IS 4 BP 347 EP 363 DI 10.1080/095119298130688 PG 17 WC Computer Science, Interdisciplinary Applications; Engineering, Manufacturing; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA ZW030 UT WOS:000074366600005 ER PT J AU Span, R Lemmon, EW Jacobsen, RT Wagner, W AF Span, R Lemmon, EW Jacobsen, RT Wagner, W TI A reference quality equation of state for nitrogen SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE caloric properties; density; equation of state; nitrogen; thermo-dynamic properties ID TEMPERATURE-RANGE; THERMODYNAMIC PROPERTIES; LIQUID-NITROGEN; T RELATION; 12 MPA; PRESSURES; DENSITY; MIXTURES; METHANE; COMPRESSIBILITY AB A new formulation describing the thermodynamic properties of nitrogen has been developed. New data sets which have been used to improve the representation of the p-p-T surface of gaseous, liquid and supercritical nitrogen, including the saturated states are now available. New measurements on the speed of sound from spherical resonators have been used to improve the accuracy of caloric properties in gaseous and supercritical nitrogen. State-of-the-art algorithms for the optimization of the mathematical structure of the equation and special functional forms for an improved description of the critical region were used to represent even the most accurate data within their experimental uncertainty. The uncertainty in density of the new reference equation of slate ranges from +/- 0.01% between 270 and 350 K at pressures less than 12 MPa, within +/- 0.02% over all other temperatures less than 550 K and pressures less than 12 MPa, and up to a maximum of +/- 0.6% at the highest pressures. The equation is valid from the triple point to temperatures of 1000 K and pressures up to 2200 MPa. The new formulation yields a reasonable extrapolation up to the limits of chemical stability of nitrogen as indicated by comparison to experimental shock tube data. Constraints regarding the structure of the equation ensure reasonable extrapolated properties up to temperatures and pressures of 5000 K and 25 GPa. For typical calibration applications, the new reference equation is supplemented by a simple but also highly accurate formulation, valid only for supercritical nitrogen between 270 and 350 K at pressures up to 30 MPa. C1 Ruhr Univ Bochum, Lehrstuhl Thermodynam, D-44780 Bochum, Germany. Univ Idaho, Ctr Appl Thermodynam Studies, Moscow, ID 83844 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Span, R (reprint author), Ruhr Univ Bochum, Lehrstuhl Thermodynam, D-44780 Bochum, Germany. NR 35 TC 71 Z9 73 U1 2 U2 12 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1998 VL 19 IS 4 BP 1121 EP 1132 DI 10.1023/A:1022689625833 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 143YZ UT WOS:000077286300011 ER PT J AU Nowarski, A Friend, DG AF Nowarski, A Friend, DG TI Application of the extended corresponding states method to the calculation of the ammonia-water mixture thermodynamic surface SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE ammonia-water mixture; extended corresponding states; thermodynamic model ID SYSTEM AB The paper presents an application of the one-fluid extended corresponding states method to the calculation of the thermodynamic surface of the ammonia-water mixture. Each pure component of the mixture is considered as a reference fluid, and to lest the behavior of the model in wide ranges of temperature and pressure, the Haar-Gallagher and the Pruss-Wagner equations of state were chosen for pure ammonia and water, respectively. To avoid numerical problems during the calculation of the pure-component equivalent substance reducing ratios (or scaling factors), a method based on the mapping defined by the extended corresponding states algorithm and two-dimensional interpolation is proposed. The estimation of the binary interaction parameters was performed using the general case of the Least squares method, i.e., the case when all measurements (observations) and unknowns are subject to uncertainty and are adjusted simultaneously with the constraint equations. The results show a strong temperature and composition dependence of both interaction parameters for the liquid, as well as for the vapor phase. A formulation for the binary interaction parameters as continuous functions of these variables was also derived and optimized using the structural optimization and regression analysis. The final statistical quality of the approach presented in the paper was assessed using the available data on thermophysical properties of the mixture. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Krakow Tech Univ, Inst Thermal Engn & Air Protect, PL-31155 Krakow, Poland. RP Friend, DG (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 10 Z9 10 U1 0 U2 4 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1998 VL 19 IS 4 BP 1133 EP 1142 DI 10.1023/A:1022641709904 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 143YZ UT WOS:000077286300012 ER PT J AU Hanley, HJM Muzny, CD Butler, BD AF Hanley, HJM Muzny, CD Butler, BD TI Surface adsorption in a surfactant/clay mineral solution SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE adsorption; cation exchange capacity; day mineral; complex; CTAB; Laponite; micelle; small angle neutron scattering (SANS); suspensions ID ANGLE NEUTRON-SCATTERING; CLAY AB The complexes formed in aqueous mixture suspensions of the synthetic clap mineral Laponite and cetyltrimethylammonium bromide (CTAB) have been investigated by small-angle neutron scattering (SANS). All suspensions were prepared with a constant initial concentration of Laponite, but the amount of CTAB was varied. The SANS intensity patterns verify that suspended Laponite in dilute suspension is in the form of disks of diameter similar to 30 nm and thickness similar to 1 nm. SANS indicates that this disk morphology, with the same diameter but with a thickness of about 4 nm, is retained for the suspended complexes, even if the CTAB in the aqueous medium is in considerable excess. SANS and chemical analysis show that a complex must adsorb CTAB to an amount corresponding to at least two multiples of the clay's cation exchange capacity to be dispersed. The amount of CTAB adsorbed as a function of CTAB in the precursor solution is discussed. We also report the effect the presence of clay on CTAB micelle formation as a function of CTAB concentration. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Hanley, HJM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 8 Z9 8 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1998 VL 19 IS 4 BP 1155 EP 1164 DI 10.1023/A:1022645810812 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 143YZ UT WOS:000077286300014 ER PT J AU Cezairliyan, A Krishnan, S Basak, D McClure, JL AF Cezairliyan, A Krishnan, S Basak, D McClure, JL TI Application of laser polarimetry to the measurement of the specific heat capacity of molybdenum in the range 2000 to 2800 K by a pulse-heating technique SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE electrical resistivity; high temperature; laser polarimeter; molybdenum; normal spectral emissivity; pulse heating; specific heat capacity; subsecond thermophysics ID TEMPERATURES AB Measurement of the specific heat capacity of molybdenum (standard reference material) in the temperature range 2000 to 2800 K is described. The method is based on rapid resistive self-heating of a solid cylindrical specimen from room temperature to the maximum temperature of interest by the passage of a subsecond-duration electrical current pulse through the specimen with simultaneous measurement of the pertinent experimental quantities. The experimental quantities yield: the current through the specimen, voltage drop across the specimen, and specimen temperature. The objective of this study is to demonstrate the feasibility of performing accurate thermophysical measurements where the specimen's true temperature is determined from measurements of surface radiance temperature with a pyrometer and normal spectral emissivity with a laser polarimeter. This approach of measuring true temperature eliminates the need of having a blackbody configuration for the specimen. In addition to the specific heat capacity, the normal spectral emissivity (at 633 nm) and electrical resistivity of molybdenum in the temperature range from 2000 to 2800 K are presented. C1 Containerless Res Inc, Evanston, IL 60201 USA. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Krishnan, S (reprint author), Containerless Res Inc, Evanston, IL 60201 USA. NR 12 TC 9 Z9 13 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1998 VL 19 IS 4 BP 1267 EP 1276 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 143YZ UT WOS:000077286300024 ER PT J AU Grachev, AA Fairall, C AF Grachev, AA Fairall, C TI Determination of the Monin-Oboukhov theory parameter z/L from the data of standard meteorological observations over the ocean SO IZVESTIYA AKADEMII NAUK FIZIKA ATMOSFERY I OKEANA LA Russian DT Article ID SURFACE-LAYER; BOUNDARY-LAYER; HEAT-FLUX; COEFFICIENTS; TEMPERATURE; CONVECTION; STABILITY; ROUGHNESS; VELOCITY; STRESS AB The data obtained from the measurements of turbulent. fluxes and standard meteorological parameters during the TOGA COARE and SCOPE experiments are used to determine the relationship between the dimensionless height zeta = z/L of the Monin-Oboukhov similarity theory and the bulk Richardson number Ri(b) determined through the mean wind velocity and the temperature and humidity differences. It is shown that, under unstable stratification, there is a high correlation between zeta and Ri(b), described by the linear dependence zeta = CRi(b). The inclusion of the effect of large-scare convective circulations, which is important only at calm winds (great negative values of zeta), modifies this relationship as zeta = CRi(b/)(1 + Ri(b)/Ri(bcr)). The numerical multiplier C and the parameter Ri(bcr) are generally expressed through the exchange coefficients and a number of other quantities. However, the mean of C is found to depend weakly on the variations in zeta and Ri(b) over a period of two or three decades, and the linear dependence between zeta and Ri(b) has a wider scope of use than previously believed. From the measurements taken at a height between 11 and 15 m, C approximate to 10 and Ri(bcr) approximate to -4 5 (with a greater scatter for the TOGA COARE data than for the SCOPE data). The use of the obtained parametrization significantly simplifies the calculations and allows one to avoid a number of iterations in numerical models, when the fluxes between the ocean and the atmosphere are determined. C1 Russian Acad Sci, Oboukhov Inst Atmospher Phys, Moscow 109017, Russia. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Grachev, AA (reprint author), Russian Acad Sci, Oboukhov Inst Atmospher Phys, Pyzhevskii Per 3, Moscow 109017, Russia. NR 25 TC 0 Z9 0 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0002-3515 J9 IZV AN FIZ ATMOS OK+ JI Izv. Akad. Nauk. Fiz. Atmos. Okean. Biol. PD JUL-AUG PY 1998 VL 34 IS 4 BP 498 EP 507 PG 10 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 121AR UT WOS:000075990400005 ER PT J AU Rukhovets, LV van den Dool, HM Barnston, AG AF Rukhovets, LV van den Dool, HM Barnston, AG TI Most predictable structures in medium-range hydrodynamic forecasts: Principal component and singular decomposition approaches SO IZVESTIYA AKADEMII NAUK FIZIKA ATMOSFERY I OKEANA LA Russian DT Article ID SURFACE-TEMPERATURE; PATTERNS; SKILL; MODEL AB The empirical orthogonal function (EOF) and singular value decomposition (SVD) approaches apply to medium-range dynamic forecasts for the summertime Northern Hemisphere to reveal the most predictable regions and atmospheric structures. Global fields of anomalies in analyses and forecasts of 500-hPa heights for periods from 1 to 20 days were obtained from the data of dynamic extended-range forecasting experiment DERF-90. The EOF technique applies separately to analysis and forecast fields. For ten-day forecasts, projections of the forecasts and corresponding analyses on the principal EOF mode of analysis correlate in the Northern Hemisphere at an anomaly correlation (AC) of 0.65, which is much greater than the AC in forecasting complete fields (about 0.20). This most predictable mode includes the Pacific/North-American oscillation. The matrices of cross correlations (analysis-forecast) were calculated to apply the SVD to analysis and forecast fields. As expected, correlations between SVD modes of forecast and analysis are higher than those between EOF modes. Maps of time correlations between grid-point values of analysis and forecast fields and the first two EOF and SVD coefficients of forecast fields (EOF and SVD heterogeneous correlation maps) were used to determine the regions of the highest verification score. It is shown that among the regions of rather high verification score are the Pacific/North-American, western and southeastern Pacific, southern Atlantic, and Indian Ocean regions. These results are supported by estimates of complete forecast fields. C1 Natl Ctr Environm Predict, Ctr Climate Forecasts, Washington, DC USA. RP Rukhovets, LV (reprint author), Natl Ctr Environm Predict, Ctr Climate Forecasts, Washington, DC USA. NR 24 TC 1 Z9 1 U1 0 U2 2 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0002-3515 J9 IZV AN FIZ ATMOS OK+ JI Izv. Akad. Nauk. Fiz. Atmos. Okean. Biol. PD JUL-AUG PY 1998 VL 34 IS 4 BP 517 EP 527 PG 11 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 121AR UT WOS:000075990400007 ER PT J AU Christopher, SA Wang, M Berendes, TA Welch, RM Yang, SK AF Christopher, SA Wang, M Berendes, TA Welch, RM Yang, SK TI The 1985 biomass burning season in South America: Satellite remote sensing of fires, smoke, and regional radiative energy budgets SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID HIGH-RESOLUTION RADIOMETER; DIURNAL VARIABILITY; FOREST-FIRES; ANTHROPOGENIC AEROSOLS; CLOUD; CLIMATE; AVHRR; EARTH; DEFORESTATION; PARAMETERS AB Using satellite imagery, more than five million square kilometers of the forest and cerrado regions over South America are extensively studied to monitor fires and smoke during the 1985 biomass burning season. The results are characterized for four major ecosystems, namely, 1) tropical rain forest, 2) tropical broadleaf seasonal, 3) savanna/grass and seasonal woods (SGW, and 4) mild/warm/hot grass/shrub (MGS). The spatial and temporal distribution of fires are examined from two different methods using the multispectral Advanced Very High Resolution Radiometer Local Area Coverage data. Using collocated measurements from the instantaneous scanner Earth Radiation Budget Experiment data, the direct regional radiative forcing of biomass burning aerosols is computed. The results show that more than 70% of the fires occur in the MGS and SGW ecosystems due to agricultural practices. The smoke generated from biomass burning has negative instantaneous net radiative forcing values for all four major ecosystems within South America. The smoke found directly over the fires has mean net radiative forcing values ranging from -25.6 to -33.9 W m(-2). These results confirm that the regional net radiative impact of biomass burning is one of cooling. The spectral and broadband properties for clear-sky and smoke regions are also presented that could be used as input and/or validation for other studies attempting to model the impact of aerosols on the earth-atmosphere system. These results have important applications for future instruments from the Earth Observing System (EOS) program. Specifically, the combination of the Visible Infrared Scanner and Clouds and the Earth's Radiant Energy System (CERES) instruments from the Tropical Rainfall Measuring Mission and the combination of Moderate Resolution Imaging Spectrometer and CERES instruments from the EOS morning crossing mission could provide reliable estimates of the direct radiative forcing of aerosols on a global scale, thereby reducing the uncertainties in current global aerosol radiative forcing values. C1 Univ Alabama, Dept Atmospher Sci, Global Hydrol & Climate Ctr, Huntsville, AL 35899 USA. NCEP, Climate Predict Ctr, Washington, DC USA. RP Christopher, SA (reprint author), Univ Alabama, Dept Atmospher Sci, Global Hydrol & Climate Ctr, 977 Explorer Blvd, Huntsville, AL 35899 USA. NR 88 TC 30 Z9 30 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 1998 VL 37 IS 7 BP 661 EP 678 DI 10.1175/1520-0450(1998)037<0661:TBBSIS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY134 UT WOS:000074589700001 ER PT J AU Tatarskaia, MS Lataitis, RJ Stankov, BB Tatarskii, VV AF Tatarskaia, MS Lataitis, RJ Stankov, BB Tatarskii, VV TI A numerical method for synthesizing atmospheric temperature and humidity profiles SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RETRIEVAL; OCEAN AB A numerical technique is described for synthesizing realistic atmospheric temperature and humidity profiles. The method uses an ensemble of radiosonde measurements collected at a site of interest. Erroneous profiles are removed by comparing their likelihood with prevailing meteorological conditions. The remaining profiles are decomposed using the method of empirical orthogonal functions. The corresponding eigenprofiles and the statistics of the expansion coefficients are used to numerically generate synthetic profiles that obey the same statistics (i.e., have the same mean, variability, and vertical correlation) as the initial dataset. The technique was applied to a set of approximately 1000 temperature and humidity soundings made in Denver, Colorado, during the winter months of 1991-95. This dataset was divided into four cloud classification categories and daytime and nighttime launches to better characterize typical profiles for the eight cases considered. It was found that 97% of the variance in the soundings could be accounted for by using only five eigenprofiles in the reconstructions. Ensembles of numerically generated profiles can be used to lest the accuracy of various retrieval algorithms under controlled conditions not usually available in practice. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Tatarskaia, MS (reprint author), NOAA, Environm Technol Lab, R-E ET4,325 Broadway, Boulder, CO 80303 USA. EM mtatarskaia@etl.noaa.gov NR 12 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 1998 VL 37 IS 7 BP 718 EP 729 DI 10.1175/1520-0450(1998)037<0718:ANMFSA>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY134 UT WOS:000074589700004 ER PT J AU Kim, JS AF Kim, JS TI A matrix formulation of magnetoresistance for an arbitrary J-fold multicarrier semiconductor system via the reduced-conductivity-tensor scheme in the nonquantizing regime SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID FIELD HALL MEASUREMENTS; ELECTRICAL CHARACTERIZATION; DEPENDENT HALL; MOBILITIES; DENSITIES; FILMS AB In this article, a matrix formulation of magnetoresistance in semiconductors is presented for an arbitrary J-fold multicarrier system which is based on the reduced-conductivity-tensor scheme and applicable in the nonquantizing regime where Landau orbital quantization is negligible. In the formalism, a unique expression of the magnetoresistance is deduced in terms of two vectors which depend on the carrier densities and mobilities, and three matrices which represent various inter-carrier couplings under the applied magnetic field. In particular, the mobility-difference matrix plays a key role, and its simple form strongly suggests a two-carrier model of magnetoresistance for a narrow continuum distribution. Explicit closed-form formulas of magnetoresistance are derived for the two-carrier (J=2) and three-carrier (J=3) systems as special cases of the general formalism. The field dependence and asymptotic behavior of the magnetoresistance are also discussed, and a two-carrier model of magnetoresistance is formally proposed. (C) 1998 American Institute of Physics. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Kim, JS (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. NR 20 TC 5 Z9 5 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1998 VL 84 IS 1 BP 292 EP 300 DI 10.1063/1.368026 PG 9 WC Physics, Applied SC Physics GA 108GP UT WOS:000075258100039 ER PT J AU Chen, WN Fryrear, DW Gillette, DA AF Chen, WN Fryrear, DW Gillette, DA TI Sedimentary characteristics of drifting sediments above an eroding loessal sandy loam soil as affected by mechanical disturbance SO JOURNAL OF ARID ENVIRONMENTS LA English DT Article; Proceedings Paper CT 4th International Conference on Aeolian Research (ICAR 4) CY JUL, 1998 CL OXFORD, ENGLAND SP British Geomorphol Res Grp DE loessal sandy loam soil; surface disturbance ratio; wind erosion; sedimentary characteristics ID WIND EROSION; VERTICAL-DISTRIBUTION; SIZE DISTRIBUTIONS; DESERT SOILS; PARTICLES; STORMS; AIR AB Our understanding of the physical mechanisms of wind erosion and dust emission stimulated by disturbance of surface soils is not adequate, even though it is a problem leading to desertification in the arid zone. Simulations of the influence of surface soil disturbance ratios on wind erosion and sedimentary characteristics of an eroded loessal sandy loam soil were conducted in an indoor wind tunnel. The results showed that the grain-size composition of the drifting soil was finer than, though similar to, the original soil, as the surface disturbance ratio increased. Wind erosion on the loessal sandy loam soil was selective. The eroded sediments were poorly sorted and became poorer with increases in the disturbance ratio and wind speed. The relative proportion of suspension population increased with increasing disturbance ratio. Several parameters such as the pattern of the frequency distribution curves, skewness and kurtosis reflected the dependence of the sedimentary characteristics of the drifting sediments on the eroding source soil. Soil erosion and dust emission by wind in drylands can be reduced by reducing unnecessary mechanical disturbance during erosion seasons. (C)1998 Academic Press Limited. C1 ARS, USDA, Wind Eros Res Stn, Big Spring, TX 79721 USA. Chinese Acad Sci, Desert Res Inst, Lanzhou 730000, Peoples R China. NOAA, Environm Res Labs, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. RP Chen, WN (reprint author), ARS, USDA, Wind Eros Res Stn, POB 909, Big Spring, TX 79721 USA. NR 42 TC 3 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0140-1963 J9 J ARID ENVIRON JI J. Arid. Environ. PD JUL PY 1998 VL 39 IS 3 BP 421 EP 440 PG 20 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA ZZ992 UT WOS:000074789900006 ER PT J AU Heller, SR AF Heller, SR TI Symantec ACT! 4.0 for Windows SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD JUL-AUG PY 1998 VL 38 IS 4 BP 772 EP 772 DI 10.1021/ci9802631 PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 103UN UT WOS:000074976400031 ER PT J AU Heller, SR AF Heller, SR TI Microsoft Office97 SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, SRD, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, SRD, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD JUL-AUG PY 1998 VL 38 IS 4 BP 773 EP 773 DI 10.1021/ci9802629 PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 103UN UT WOS:000074976400032 ER PT J AU Smith, TM Livezey, RE Shen, SS AF Smith, TM Livezey, RE Shen, SS TI An improved method for analyzing sparse and irregularly distributed SST data on a regular grid: The tropical Pacific Ocean SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURES AB An improved method for interpolating sparsely sampled climatological data onto a regular grid is shown. The method uses the spatial and temporal covariance of the field, along with the sparse data, to fill the full grid. This improves on similar methods that have recently been developed by eliminating the development of features that are not sufficiently supported by the data (i.e., overfitting). Statistical tests are used to tune the method to represent as much variability as the spatial-temporal information will support without overfitting. The method is further improved by a data-checking procedure that detects and removes suspect data. The method is developed and evaluated by interpolating tropical Pacific sea surface temperature (SST) monthly anomalies to a regular grid for the 1856-1995 period. Ship data averaged to 5 degrees squares are used as input and are interpolated to a complete 1 degrees grid. Comparing the results to interpolations using other methods shows this method's quantitative improvements where satellite data are available fcr validation. Comparisons in the presatellite era show sharper and stronger anomaly patterns with this method, compared to another method developed for use with sparse data. Also shown are several periods when data are so sparse that only very weak SST anomalies may be reliably reconstructed in the tropical Pacific (i.e., before 1870 and 1915-25). In future research, the global SST and possibly other climatological fields will be gridded using improved methods. C1 NOAA, NWS, NCEP, CPC, Camp Springs, MD USA. Univ Alberta, Dept Math Sci, Edmonton, AB, Canada. RP Smith, TM (reprint author), Natl Ctr Environm Protect, Anal Branch, Climate Predict Ctr, World Weather Bldg,5200 Auth Rd,Room 605,W-NP52, Camp Springs, MD 20746 USA. RI Smith, Thomas M./F-5626-2010 OI Smith, Thomas M./0000-0001-7469-7849 NR 14 TC 32 Z9 34 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1998 VL 11 IS 7 BP 1717 EP 1729 DI 10.1175/1520-0442(1998)011<1717:AIMFAS>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 109MT UT WOS:000075326900014 ER PT J AU Bennett, AF Chua, BS Harrison, DE McPhaden, MJ AF Bennett, AF Chua, BS Harrison, DE McPhaden, MJ TI Generalized inversion of tropical atmosphere-ocean data and a coupled model of the tropical Pacific SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; EASTERN EQUATORIAL PACIFIC; EL-NINO; HEAT-FLUX; SOUTHERN OSCILLATION; DATA ASSIMILATION; WIND; VARIABILITY; CIRCULATION; DYNAMICS AB It is hypothesized that the circulation of the tropical Pacific Ocean and atmosphere satisfies the equations of a simple coupled model to within errors having specified covariances, and that the Tropical Atmosphere-Ocean array (TAO) measures the circulation to within errors also having specified covariances. This hypothesis is tested by finding the circulation that is the weighted least squares best fit to the dynamics of the simple model, to its initial and boundary conditions, and to a year of monthly mean TAO data for sea surface temperature, for the depth of the 20 degrees C isotherm, and for surface winds. The fit is defined over the entire tropical Pacific and from 1 April 1994 to 31 March 1995. The best-fit circulation or state estimate is calculated using variational methods. Posterior error covariances are estimated using statistical simulation. The best fit is also subjected to a significance test. It is found that, although the fit to data is largely within standard errors, the misfit to dynamics is significantly larger than standard errors. These standard errors are estimated a priori, and with difficulty, from published scale analysts of tropical circulation. An examination of the dynamical residuals indicates that the simple coupled model should be improved by including momentum advection both in the oceanic and atmospheric components. C1 Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Natl Oceanog & Atmospher Adm, Pacific Marine Environm Lab, Seattle, WA USA. RP Oregon State Univ, Coll Ocean & Atmospher Sci, Oceanog Adm Bldg 104, Corvallis, OR 97331 USA. EM bennett@oce.orst.edu RI Harrison, Don/D-9582-2013; McPhaden, Michael/D-9799-2016 NR 40 TC 33 Z9 33 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JUL PY 1998 VL 11 IS 7 BP 1768 EP 1792 DI 10.1175/1520-0442(1998)011<1768:GIOTAO>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 109MT UT WOS:000075326900017 ER PT J AU Sriram, RD AF Sriram, RD TI Information technology for engineering design SO JOURNAL OF COMPUTING IN CIVIL ENGINEERING LA English DT Editorial Material C1 NIST, Mfg Engn Lab, Mfg Syst Integrat Div, Engn Design Technol Grp, Gaithersburg, MD 20899 USA. RP Sriram, RD (reprint author), NIST, Mfg Engn Lab, Mfg Syst Integrat Div, Engn Design Technol Grp, Gaithersburg, MD 20899 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0887-3801 J9 J COMPUT CIVIL ENG JI J. Comput. Civil. Eng. PD JUL PY 1998 VL 12 IS 3 BP 123 EP 125 DI 10.1061/(ASCE)0887-3801(1998)12:3(123) PG 3 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA ZU202 UT WOS:000074172500002 ER PT J AU Coriell, SR McFadden, GB Sekerka, RF Boettinger, WJ AF Coriell, SR McFadden, GB Sekerka, RF Boettinger, WJ TI Multiple similarity solutions for solidification and melting SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE alloy solidification; alloy melting; multiple solutions; similarity solutions; lead-tin ID DIFFUSION COUPLES AB We explore multiple similarity solutions in one spatial dimension during the solidification or melting of a binary ahoy. The configuration is analogous to that of a diffusion couple, for which multiple similarity solutions in isothermal ternary alloys were discovered by Coates and Kirkaldy and explored further by Maugis et al. We proceed by fmding analytical solutions to the transport equations for heat and solute. Under the assumption of local equilibrium at the interface, a transcendental equation for the parabolic growth rate constant is obtained, which we solve numerically. We use a lead-tin alloy as an example, and examine the situation in which each member of the diffusion couple is a stable phase, one solid and one liquid. The "diffusion path" begins at the composition and temperature of one such phase, crosses the two-phase region at a tie line, and terminates at the composition and temperature of the other phase. For the cases examined here in which there are multiple solutions, such diffusion paths enter the two-phase region before crossing the tie line. The concomitant temperature and concentration profiles are also explored and? in some cases, are quite counterintuitive. For a pure material, we have only found multiple solutions when the solid is superheated, which may be difficult experimentally. Experiments to explore the binary alloy case should, however, be possible. We speculate about the physical manifestation of these multiple solutions by considerations including adjustment to initial conditions, interface kinetics, non-similarity solutions, and instabilities. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Carnegie Mellon Univ, Dept Phys & Math, Pittsburgh, PA 15213 USA. RP Coriell, SR (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 17 TC 17 Z9 18 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 1998 VL 191 IS 3 BP 573 EP 585 DI 10.1016/S0022-0248(98)00249-8 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 104TY UT WOS:000075032500037 ER PT J AU Chowdhury, EA Dashiell, M Qiu, G Olowolafe, JO Jonczyk, R Smith, D Barnett, A Kolodzey, J Unruh, KM Swann, CP Suehle, J Chen, YA AF Chowdhury, EA Dashiell, M Qiu, G Olowolafe, JO Jonczyk, R Smith, D Barnett, A Kolodzey, J Unruh, KM Swann, CP Suehle, J Chen, YA TI Structural, optical and electronic properties of oxidized AlN thin films at different temperatures SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE AlN; aluminum oxide; gate insulators; thermal oxidation; thin films ID OXIDATION; COATINGS; AL2O3 AB We report on the properties of a novel insulator, AlO:N for application in semiconductors produced by thermally oxidizing AlN thin films. The process steps were similar to those used for SiO2, creating the possibility of a new technology for metal-insulator-semiconductor field effect devices and integrated circuits. Thin films of AlN were deposited by radio-frequency magnetron reactive sputtering on p-type silicon or fused quartz substrates. As-deposited AlN film thickness ranged from 0.05 to 0.7 mu m, with polycrystalline structure revealed by x-ray diffraction. Oxidation was performed under O-2 flow at 800 to 1100 degrees C for 1-4 h. AlN films were oxidized partially or fully into Al2O3, depending on initial thickness, oxidation temperature and time. X-ray diffraction indicates the presence of several phases of Al2O3 at 1000 degrees C, whereas at 1100 degrees C, only the alpha-Al2O3 phase was found. Considering the importance of surface field effect device applications, the surfaces of oxidized films were examined with atomic force microscopy in air, and a clear change was observed in the surface structure of the oxidized film from that of as-deposited ALN films. Capacitance-voltage measurements of metal-oxide-semiconductor structures yielded a dielectric constant of AlO:N between 8-12 and a net oxide-trapped-charge density of similar to 10(11) cm(-2). Using Fourier transform infrared spectrometry transmittance and reflectance, some alpha-Al2O3 modes were observed. In this paper, we describe the general properties of the oxide thin films, bulk and interface, at different temperatures. C1 Univ Delaware, Dept Elect & Comp Engn, Newark, DE 19716 USA. Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA. Bartol Res Inst, Sharp Lab, Newark, DE 19716 USA. NIST, Gaithersburg, MD 20899 USA. Univ Maryland, Ctr Reliabil Engn, College Pk, MD 20742 USA. RP Chowdhury, EA (reprint author), Univ Delaware, Dept Elect & Comp Engn, Newark, DE 19716 USA. NR 13 TC 7 Z9 7 U1 0 U2 8 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUL PY 1998 VL 27 IS 7 BP 918 EP 922 DI 10.1007/s11664-998-0119-y PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 101QX UT WOS:000074880600018 ER PT J AU Ahn, BH Richmond, AD Kamide, Y Kroehl, HW Emery, BA de la Beaujardiere, O Akasofu, SI AF Ahn, BH Richmond, AD Kamide, Y Kroehl, HW Emery, BA de la Beaujardiere, O Akasofu, SI TI An ionospheric conductance model based on ground magnetic disturbance data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HEIGHT-INTEGRATED CONDUCTIVITIES; HIGH-LATITUDE IONOSPHERE; ELECTRON-PRECIPITATION; AURORAL ELECTROJETS; MORNING SECTOR; ENERGY FLUX; FIELDS; CURRENTS; SOLAR; OVAL AB An attempt is made to construct an improved ionospheric conductance model employing ground magnetic disturbance data as input. For each of-the different regions in the auroral electrojets specified by different combinations of horizontal (Delta H) and vertical (Delta Z) magnetic perturbations, as well as by magnetic local time (MLT), an empirical relationship is obtained between the ionospheric conductance deduced from Chatanika radar data and magnetic disturbances from the nearby College magnetic station. The error involved in the empirical formula is generally of the order of 20-50%. However, some sectors are so poorly covered that uncertainty estimates; cannot be made. The new formulas are applied to an average magnetic disturbance distribution to deduce the average conductance distribution. This is compared with a conductance model based on electron precipitation data [Hardy et al., 1987], finding good agreement in terms of the magnitude and distribution pattern. Combining our empirical relationships with the empirical formulas proposed by Robinson et al. [1987], the average energy and energy flux of precipitating electrons are also estimated. Notable similarities exist between the global distribution patterns of these and those obtained by Hardy et al. [1985]. It is proposed that the present conductance model can be used to complement more direct measurements in order to obtain the global distribution needed to study the large-scale electrodynamics of the polar ionosphere. Several interesting characteristics about the auroral electrojet system are apparent from the empirical relationship: (1) For a given magnitude of Delta H, the electric field is relatively stronger in the eastward electrojet region than in the westward electrojet region. (2) The electric field plays a greater role in the intensification of electrojet current than the ionospheric conductance does in the poleward half of the westward electrojet, whereas the opposite trend is apparent in the equatorward half. However, no such different roles of the electric field and conductance is noticeable in the eastward electrojet region. (3) The auroral conductance enhancements tend to be largest around midnight, due to more intense particle fluxes there. (4) The mean particle energy depends on MLT but is relatively insensitive to magnetic activity. C1 Kyungpook Natl Univ, Dept Earth Sci, Taegu 702701, South Korea. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Natl Sci Fdn, Off Polar Programs, Arlington, VA 22230 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Nagoya Univ, Solar Terrestrial Environm Lab, Toyokawa 442, Japan. NOAA, Natl Geophys Data Ctr, Boulder, CO 80303 USA. RP Ahn, BH (reprint author), Kyungpook Natl Univ, Dept Earth Sci, Taegu 702701, South Korea. NR 25 TC 49 Z9 50 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1998 VL 103 IS A7 BP 14769 EP 14780 DI 10.1029/97JA03088 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZY130 UT WOS:000074589300022 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr Solar Terr Phys A, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr Solar Terr Phys A, Boulder, CO 80303 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUL 1 PY 1998 VL 103 IS A7 BP 15009 EP 15009 DI 10.1029/98JA01709 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZY130 UT WOS:000074589300045 ER PT J AU Anagnostou, EN Krajewski, WF Seo, DJ Johnson, ER AF Anagnostou, Emmanouil N. Krajewski, Witold F. Seo, Dong-Jun Johnson, Edward R. TI MEAN-FIELD RAINFALL BIAS STUDIES FOR WSR-88D SO JOURNAL OF HYDROLOGIC ENGINEERING LA English DT Article AB Real-time radar-rainfall bias adjustment procedures for weather surveillance Doppler radar (WSR-88D) are investigated. Statistical analysis of the mean-field bias is performed on a 2-year record of WSR-88D observations from Tulsa, Okla., and rain gauge measurements from a dense network under the radar umbrella. The analysis shows strong seasonal effect. A data-based Monte Carlo simulation experiment is performed on the same data to quantify the sampling error of estimated bias for varying rain gauge network densities. Simulation results show (1) that the sampling error decreases proportionally to the square of the rain gauge network density; and (2) that the sampling error is higher in the warm season. The performance of three mean-field radar-rainfall bias estimation and prediction algorithms is investigated. The algorithms include the WSR-88D precipitation adjustment procedure, the adaptive error parameter technique, and the maximum likelihood autoregressive model. A Monte Carlo simulation experiment is used to assess the algorithms' error statistics for the two seasons, three accumulation timescales, and two modes of operation (prediction and update). Results show significant seasonal and time-scale effects. C1 [Anagnostou, Emmanouil N.] Univ Space Res Assn, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Anagnostou, Emmanouil N.; Krajewski, Witold F.] Univ Iowa, Iowa Inst Hydr Res, Iowa City, IA 52242 USA. [Seo, Dong-Jun; Johnson, Edward R.] Nat Weather Serv, Ofc Hydro, Silver Spring, MD 20910 USA. [Johnson, Edward R.] Nat Weather Serv, Hydrol Operat Div, Silver Spring, MD 20910 USA. RP Anagnostou, EN (reprint author), Univ Space Res Assn, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. FU National Oceanic and Atmospheric Administration [NA47WH0495] FX This paper is dedicated by W. F. K. to the memory of Dr. Dah-Syang Lin, friend, colleague, and student who passed away at a young age before realizing his full potential. The writers also acknowledge and appreciate useful discussions with Dr. James A. Smith from Princeton University and Dr. Grzegorz J. Ciach from the Iowa Institute of Hydraulic Research. The study was supported by the National Oceanic and Atmospheric Administration under a Cooperative Agreement No. NA47WH0495 between the Office of Hydrology of the NWS and The University of Iowa Institute of Hydraulic Research. NR 54 TC 52 Z9 52 U1 0 U2 4 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 1084-0699 J9 J HYDROL ENG JI J. Hydrol. Eng. PD JUL PY 1998 VL 3 IS 3 BP 149 EP 159 DI 10.1061/(ASCE)1084-0699(1998)3:3(149) PG 11 WC Engineering, Civil; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA V15AM UT WOS:000207774900001 ER PT J AU Craig, RM Gilbert, SL Hale, PD AF Craig, RM Gilbert, SL Hale, PD TI High-resolution, nonmechanical approach to polarization-dependent transmission measurements SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE liquid-crystal retarders; liquid-crystal variable retarders; Mueller matrix; polarization dependence; polarization-dependent loss (PDL); polarization-dependent transmission; synchronous detection ID SYSTEMS; GAIN AB We have implemented an automated, nonmechanical approach to the measurement of polarization dependent loss (and, equivalently, gain). We use a deterministic fixed-states method to derive Mueller matrix elements from intensity measurements at specific polarization states. Voltage-modulated liquid-crystal variable retarders set the polarization states. Synchronous detection is employed to increase the signal-to-noise ratio (SNR) of the system and thereby allow measurement resolution to better than 0.001 dB, We present polarization-dependent loss measurements from 0.0016 to 0.56 dB at 1550 nm to verify performance. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Craig, RM (reprint author), Natl Inst Stand & Technol, Boulder, CO 80303 USA. RI Hale, Paul/B-1737-2013 NR 18 TC 34 Z9 34 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD JUL PY 1998 VL 16 IS 7 BP 1285 EP 1294 DI 10.1109/50.701407 PG 10 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA ZX363 UT WOS:000074508000017 ER PT J AU Ahn, HS Jahanmir, S Slotwinski, JA Blessing, GV AF Ahn, HS Jahanmir, S Slotwinski, JA Blessing, GV TI Detection of contact damage in ceramics by an ultrasonic method SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-NITRIDE; ACOUSTIC MICROSCOPY; MATERIAL REMOVAL; MICROFRACTURE; ALUMINA; CRACK AB A pulse-echo ultrasonic technique consisting of focused normal-incident compressional waves was used for the detection and evaluation of surface and subsurface damage in micaceous glass-ceramic and silicon nitride samples. The damage was produced by indentation with a tungsten carbide ball. The nature of the damage was found to be material-dependent and was classified into two types: Hertzian cone cracks in the silicon nitride, and distributed subsurface microcracks in the glass-ceramic. While the cone cracks were visible on the surface as circular ring cracks, the distributed subsurface microcracks were not associated with any visible surface cracks. Both the cone cracks and the distributed subsurface microcracks were easily detected by the ultrasonic technique. In addition, the ultrasonic beam was focused to different depths below the surface of the glass-ceramic sample to probe the subsurface region containing the microfracture damage. C1 Korea Inst Sci & Technol, Seoul, South Korea. NIST, Gaithersburg, MD 20899 USA. RP Korea Inst Sci & Technol, Seoul, South Korea. NR 22 TC 1 Z9 1 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD JUL PY 1998 VL 13 IS 7 BP 1899 EP 1904 DI 10.1557/JMR.1998.0269 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA ZX311 UT WOS:000074502800030 ER PT J AU Harvey, AH Gallagher, JS Sengers, JMHL AF Harvey, AH Gallagher, JS Sengers, JMHL TI Revised formulation for the refractive index of water and steam as a function of wavelength, temperature and density SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE formulation; infrared; ITS-90; molar refraction; refractive index; steam; supercooled water; supercritical steam; ultraviolet; visible; water ID OPTICAL-CONSTANTS; LIQUID WATER; PURE WATER; VALUES; ITS-90; RANGE AB Schiebener et al. published a formulation for the refractive index of water and steam in 1990 [J. Phys. Chem. Ref. Data 19, 677 (1990)]. It covered the ranges 0.2 to 2.5 mu m in wavelength, -12 to 500 degrees C in temperature, and 0 to 1045 kg m(-3) in density. The formulation was adopted by the International Association for the Properties of Water and Steam (IAPWS) in 1991. In the present article, the data, after conversion to ITS-90, have been refitted to the same functional form, but based on an improved equation of state for water adopted by IAPWS in 1995, The revised coefficients are reported, and some tabular material is provided. The revised refractive-index formulation was adopted by IAPWS in 1997 and is available as part of a National Institute of Standards and Technology Standard Reference Database. For most conditions, the revised formulation does not differ significantly from the previous one. A substantial improvement has been obtained in supercooled water at ambient pressure, where the previous formulation was defective. Special attention has been paid to the behavior of the refractive index in the near infrared, where strongly oscillating data were reported after the correlation of Schiebener et al, had appeared, leading to subsequent curtailing of the range of validity of the formulation. Newer results do not show these oscillations. They are compared with the revised formulation. (C) 1998 American Institute of Physics and American Chemical Society. [S0047-2689(98)00204-9]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Harvey, AH (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 25 TC 174 Z9 176 U1 7 U2 46 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 1998 VL 27 IS 4 BP 761 EP 774 PG 14 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 106HF UT WOS:000075123300001 ER PT J AU van Meurs, P AF van Meurs, P TI Interactions between near-inertial mixed layer currents and the mesoscale: The importance of spatial variabilities in the vorticity field SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID UPPER-OCEAN; NORTHEAST PACIFIC; STRONG STORM; LAGRANGIAN DRIFTERS; WAVE-PROPAGATION; WIND; OSCILLATIONS; VELOCITY; MOTIONS AB Satellite-tracked mixed-layer drifter data from the 1987 Ocean Storms Experiment in the northeast Pacific are used to study the temporal and spatial variability in the near-inertial currents of the surface mixed layer. The data suggest that the near-inertial currents interact with the mesoscale vorticity. To explore the exact nature of this relationship, an asymptotic analysis is extended to include the mesoscale and it is shown that not only gradients in the planetary vorticity (beta) but also the gradients in the mesoscale vorticity affect the generation and evolution of near-inertial mixed layer currents. While the beta effect is relevant for the large-scale evolution of the near-inertial currents, the vorticity gradients of the mesoscale field determine the local behavior of near-inertial currents. Using a three-dimensional model it is shown that areas of large gradients in the mesoscale vorticity coincide with areas of low near-inertial energy. The smaller spatial scales in the near-inertial energy, generated by the vorticity held, result in faster decay of near-inertial currents. The findings that the near-inertial currents interact with the mesoscale are in apparent contradiction with previous research in the same area. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP van Meurs, P (reprint author), 1027A NE 130th St, Seattle, WA 98125 USA. NR 29 TC 25 Z9 25 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUL PY 1998 VL 28 IS 7 BP 1363 EP 1388 DI 10.1175/1520-0485(1998)028<1363:IBNIML>2.0.CO;2 PG 26 WC Oceanography SC Oceanography GA 104UP UT WOS:000075034500004 ER PT J AU Zeisler, R Heller-Zeisler, SF Fajgelj, A AF Zeisler, R Heller-Zeisler, SF Fajgelj, A TI On achieving measurement quality in air pollution studies employing nuclear techniques SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 4th International Conference on Methods and Applications of Radioanalytical Chemistry CY APR 06-11, 1997 CL KAILUA KONA, HAWAII SP Amer Nucl Soc, Isotopes & Radiat Div, Amer Nucl Soc, Biol & Med Div, Canadian Nucl Soc, Amer Chem Soc, Div Nucl Chem & Technol AB Instrumental neutron activation. proton induced X-ray emission and energy-dispersive X-ray fluorescence procedures were employed for trace element determinations in samples of fractionated air particulate matter deposited on filters. The techniques are well suited to analyse the generally small samples. However, indications of bias between techniques were found in the analysis of individual filters. This may be rectified with the development of matched reference materials. The three techniques were used in this work to determine trace elements in bulk samples of air particulate matter and in a set of intercomparison samples of fine air particulate matter on filters. The test results on these materials showed good agreement among the employed techniques and demonstrated the quality potential of air particulate analyses. C1 Int Atom Energy Agcy, Labs Seibersdorf, A-1400 Vienna, Austria. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. RP Zeisler, R (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 9 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 1998 VL 233 IS 1-2 BP 15 EP 19 DI 10.1007/BF02389640 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 106BR UT WOS:000075110300003 ER PT J AU Heller-Zeisler, SF Donais, MK Zeisler, R AF Heller-Zeisler, SF Donais, MK Zeisler, R TI Instrumental neutron activation analysis for quality assurance of a hair reference material for mercury speciation SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 4th International Conference on Methods and Applications of Radioanalytical Chemistry CY APR 06-11, 1997 CL KAILUA KONA, HAWAII SP Amer Nucl Soc, Isotopes & Radiat Div, Amer Nucl Soc, Biol & Med Div, Canadian Nucl Soc, Amer Chem Soc, Div Nucl Chem & Technol ID METHYLMERCURY AB Instrumental neutron activation analysis (INAA) has been employed in the investigation of mass balance for mercury species analysis in the analytical process. A new human hair reference material (IAEA-085) was analyzed for methylmercury using a solid/liquid extraction procedure, with samples of extracts, residues, and untreated samples being analyzed by INAA. The certified reference material NIES CRM No. 13, human hair, was analyzed in parallel. From the results obtained through the mass balance studies, it was found that the extraction procedure was quantitatively complete, and that there was no difference between the mass balance of Hg and the total Hg in the untreated materials. C1 Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Heller-Zeisler, SF (reprint author), Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NR 6 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 1998 VL 233 IS 1-2 BP 55 EP 57 DI 10.1007/BF02389647 PG 3 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 106BR UT WOS:000075110300010 ER PT J AU Inn, KGW AF Inn, KGW TI NIST MQA for environmental radioactivity measurements SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 4th International Conference on Methods and Applications of Radioanalytical Chemistry CY APR 06-11, 1997 CL KAILUA KONA, HAWAII SP Amer Nucl Soc, Isotopes & Radiat Div, Amer Nucl Soc, Biol & Med Div, Canadian Nucl Soc, Amer Chem Soc, Div Nucl Chem & Technol ID STANDARD REFERENCE MATERIAL; ACTINIDES AB The Ionizing Radiation Division of the National Institute of Standards and Technology (NIST) has implemented several quality assurance programs to provide a consistent basis for environmental-level national and international ionizing radiation measurement credibility and comparability. These programs cut across a variety of sectors that include: (1) personnel protection; (2) survey-instrument calibration; (3) environmental radiochemistry and (4) radiobioassay. The four basic elements of the MQA programs are: (1) conformance to promulgated consensus criteria; (2) documented in-house quality assurance and control practice; (3) periodic performance evaluations using appropriate testing materials and instruments; and (4) periodic on-site assessments by technical experts. The periodic performance evaluations are important for the demonstration of measurement traceability to the national and international physical standards. Traceability testing, however, must be augmented by the other elements to provide the strongest rationale for measurement assurance. This paper will describe the NIST programs and future directions for new programs. C1 US Dept Commerce, Natl Inst Stand & Technol, Technol Adm, Phys Lab,Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Inn, KGW (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Technol Adm, Phys Lab,Ionizing Radiat Div, Gaithersburg, MD 20899 USA. NR 13 TC 2 Z9 2 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 1998 VL 233 IS 1-2 BP 69 EP 79 DI 10.1007/BF02389650 PG 11 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 106BR UT WOS:000075110300013 ER PT J AU Becker, DA AF Becker, DA TI Characterization and use of the new NIST rapid pneumatic tube irradiation facility SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 4th International Conference on Methods and Applications of Radioanalytical Chemistry CY APR 06-11, 1997 CL KAILUA KONA, HAWAII SP Amer Nucl Soc, Isotopes & Radiat Div, Amer Nucl Soc, Biol & Med Div, Canadian Nucl Soc, Amer Chem Soc, Div Nucl Chem & Technol AB Recently a new rapid pneumatic tube facility was inserted into a long unused location in the NIST 20 MW nuclear reactor. This facility was designed and constructed specifically for rapid INAA using short lived activation products. Included is a computer controlled console which uses fast sensors to accurately measure the irradiation capsule flight time, and a loss-free counting system connected to a 32% efficient HPGe detector with a transistor reset preamplifier. Measurement of travel times from end-of-irradiation to detector were 473+/-8 ms. Measurement of the thermal neutron fluence rate was 5.0 . 10(13) n . cm(-2) . s(-1). The other three pneumatic tubes in the NIST reactor have transfer times of 3 to 15 seconds, and no timing capability more accurate than human response. This new facility substantially improves our ability to accurately determine activation products with half-lives from 1 to 100 seconds. Characterization information reported on this new irradiation facility includes absolute fluence measurements, fluence rate variations within the capsule and variations with time, and determination of analytical sensitivities for fluorine-20, selenium-77m, and silver-110g. C1 Natl Inst Stand & Technol, Nucl Methods Grp, Div Analyt Chem, CSTL, Gaithersburg, MD 20899 USA. RP Becker, DA (reprint author), Natl Inst Stand & Technol, Nucl Methods Grp, Div Analyt Chem, CSTL, Gaithersburg, MD 20899 USA. NR 7 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 1998 VL 233 IS 1-2 BP 155 EP 159 DI 10.1007/BF02389664 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 106BR UT WOS:000075110300027 ER PT J AU Slifka, AJ Filla, BJ Phelps, JM AF Slifka, AJ Filla, BJ Phelps, JM TI Thermal conductivity of magnesium oxide from absolute, steady-state measurements SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE guarded hot plate; magnesium oxide; thermal conductivity AB The thermal conductivity of polycrystalline magnesium oxide has been measured over the temperature range from 400 K to 1300 K using a modified guarded-hot-plate design. Three different thicknesses of specimens having 93 % of theoretical density were tested to verify the operation, accuracy, and reproducibility of our apparatus. The measured thermal conductivity ranges from 30 W.m(-1).K-1 down to 8 W.m(-1).K-1 and has an inverse-temperature functionality. The results agree well with literature values for this material. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Slifka, AJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 9 TC 22 Z9 23 U1 0 U2 10 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1998 VL 103 IS 4 BP 357 EP 363 DI 10.6028/jres.103.021 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 126DR UT WOS:000076278100001 PM 28009383 ER PT J AU Laitano, RF Lamperti, PJ Toni, MP AF Laitano, RF Lamperti, PJ Toni, MP TI Comparison of the NIST and ENEA air kerma standards SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE air kerma; Co-60; comparison of standards; gamma-ray standards; transfer chambers; x-ray standards ID ION CHAMBERS; ATTENUATION; BEAMS AB A comparison was made between the National Institute of Standards and Technology (NIST) and Ente per le Nuove Technologie 1'Energia e 1'Ambiente (ENEA) air kerma standards for medium energy x rays and Co-60 gamma rays. The comparison took place at ENEA in June 1994. Two different transfer chambers from NIST were used for the comparison. The measurements were made at radiation qualities similar to those used at the Bureau International des Poids et Mesures (BIPM) (generating voltages of too kV, 135 kV, 180 kV and 250 kV, respectively) and with Co-60 gamma radiation. The transfer chamber calibration factors obtained at the NIST and at the ENEA agreed with one another to 0.03 % for Co-60 gamma radiation and between 0.1 % to 0.8 % for the medium energy x-ray beam codes. C1 ENEA, Dipartimento Ambiente, Ctr Ric Casaccia, Ist Nazl Metrol Radiazioni Ionizzanti, Rome, Italy. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Laitano, RF (reprint author), ENEA, Dipartimento Ambiente, Ctr Ric Casaccia, Ist Nazl Metrol Radiazioni Ionizzanti, CP 2400, Rome, Italy. NR 26 TC 3 Z9 3 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1998 VL 103 IS 4 BP 365 EP 378 DI 10.6028/jres.103.022 PG 14 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 126DR UT WOS:000076278100002 PM 28009356 ER PT J AU Wong-Ng, W Cook, LP AF Wong-Ng, W Cook, LP TI Liquidus diagram of the Ba-Y-Cu-O system in the vicinity of the Ba2YCu3O6+x phase field SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE Ba2YCu3O6+x; liquid compositions; liquid immiscibility; phase equilibria; primary phase field; superconductors ID OXYGEN-PRESSURE; CRYSTAL-GROWTH; SOLIDIFICATION; Y2O3-BAO-CUO; TEMPERATURE; OXIDES; YBCO; YBA2CU3O7-DELTA; COMPATIBILITIES; 950-DEGREES-C AB This paper describes the melting equilibria in the vicinity of the high T-c phase Ba2YCu3O6+x, including evidence for two Ba-Y-Cu-O immiscible liquids. Melting equilibria have been investigated in purified air using a combination of differential thermal analysis (DTA), thermogravimetric analysis (TGA), powder x-ray diffraction (XRD), MgO wick entrapment of liquid for analysis, scanning electron microscopy (SEM) coupled with energy dispersive x-ray analysis (EDS), and hydrogen reduction for determination of copper oxidation state. For relatively barium-rich compositions, it was necessary to prepare the starting materials under controlled atmosphere conditions using BaO. A liquidus diagram was derived from quantitative data for the melts involved in various melting reactions. In general the 1/2(Y2O3) contents of the melts participating in these equilibria were low (mole fraction <4 %). The primary phase field of Ba2YCu3O6+x occurs at a mole fraction of <2.0 % 1/2Y(2)O(3) and lies very close along the BaO-CuOx edge, extending from a mole fraction of approximate to 43 % CuO to a mole fraction of approximate to 76 % CuO. It is divided by a liquid miscibility gap and extends on either side about this gap. The topological sequence of melting reactions associated with the liquidus is presented as a function of temperature. Implications for the growth of Ba2YCu3O6+x crystals are discussed. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wong-Ng, W (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 53 TC 19 Z9 19 U1 0 U2 8 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1998 VL 103 IS 4 BP 379 EP 403 DI 10.6028/jres.103.023 PG 25 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 126DR UT WOS:000076278100003 PM 28009382 ER PT J AU Mitchell, WF AF Mitchell, WF TI The refinement-tree partition for parallel solution of partial differential equations SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE partitioning algorithm; partial differential equations; refinement tree partitions ID ADAPTIVE GRIDS; MULTILEVEL AB Dynamic load balancing is considered in the context of adaptive multilevel methods for partial differential equations on distributed memory multiprocessors. An approach that periodically repartitions the grid is taken. The important properties of a partitioning algorithm are presented and discussed in this context. A partitioning algorithm based on the refinement tree of the adaptive grid is presented and analyzed in terms of these properties. Theoretical and numerical results are given. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 19 TC 8 Z9 8 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD JUL-AUG PY 1998 VL 103 IS 4 BP 405 EP 414 DI 10.6028/jres.103.024 PG 10 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 126DR UT WOS:000076278100004 PM 28009355 ER PT J AU Vangel, MG AF Vangel, MG TI ANOVA estimates of variance components for quasi-balanced mixed models SO JOURNAL OF STATISTICAL PLANNING AND INFERENCE LA English DT Article DE Henderson method; quadratic form; staggered design; three-stage design AB This article examines a simple and intuitively appealing way to estimate variance components in mixed models: perform as many ordinary least-squares regressions as there are variance components, using dummy variables for all but one random effect in each regression. By equating these residual sums of squares to their expectations, unbiased estimates of all of the variance components can be obtained. This approach is a special case of Method 3 of Henderson (Biometrics 9 (1953) 226-252). A quasi-balanced mixed model is defined here to be a model in which the indicator matrix for one of the random effects is essentially arbitrary, but the model obtained by omitting this random effect is nested and balanced. For quasi-balanced normal models the exact distributions of residual sums of squares are derived; they lead to the exact distributions of Henderson Method 3 estimates. An example involving strength data for a composite material is discussed in detail. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, US Dept Commerce, Stat Engn Div, Gaithersburg, MD 20899 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3758 J9 J STAT PLAN INFER JI J. Stat. Plan. Infer. PD JUL 1 PY 1998 VL 70 IS 1 BP 139 EP 148 DI 10.1016/S0378-3758(97)00172-9 PG 10 WC Statistics & Probability SC Mathematics GA ZZ325 UT WOS:000074718100011 ER PT J AU Wagner, RP Nedzelnitsky, V AF Wagner, RP Nedzelnitsky, V TI Determination of acoustic center correction values for type LS2aP microphones at normal incidence SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article; Proceedings Paper CT 130th Meeting of the Acoustical-Society-of-America CY NOV 27-DEC 01, 1995 CL ST LOUIS, MISSOURI SP Acoust Soc Amer AB Frequency-dependent acoustic center correction values are required to obtain accurate microphone calibrations in the free-field by the reciprocity technique. These values were determined for IEC type LS2aP microphones at normal incidence by utilizing the theoretical inverse relationship between the sound pressure amplitude at the acoustic center of a receiver and the distance between acoustic centers of source and receiver. A dynamic signal analyzer was used to measure the gain factor between the amplified output voltage of the receiver and the source input voltage at 500-Hz intervals in the extended frequency range 2-50 kHz. This procedure allowed all the data for a microphone pair to be gathered within several hours for microphone diaphragm separations from 101-311 mm at 10-mm intervals. At each frequency, the reciprocal of this gain factor as a function of microphone diaphragm separation was fit to a straight line after correction for atmospheric effects, including attenuation of sound caused by atmospheric absorption. Mean acoustic center correction values (from four microphones combined in six pairs) were calculated using the parameters obtained from the fit and found to be in good agreement with published values calculated by the boundary element method, as well as with values predicted by scaling published values of the acoustic center correction for microphones with a geometrical configuration similar to that of IEC type LS1P microphones. [S0001 -4966(98)01407-6]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wagner, RP (reprint author), Natl Inst Stand & Technol, Sound Bldg,Room A147, Gaithersburg, MD 20899 USA. NR 11 TC 5 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUL PY 1998 VL 104 IS 1 BP 192 EP 203 DI 10.1121/1.423288 PG 12 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA ZY164 UT WOS:000074592700023 ER PT J AU Wong-Ng, WK Cook, LP Jiang, F AF Wong-Ng, WK Cook, LP Jiang, F TI Melting equilibria of the Bi-Sr-Ca-Cu-O (BSCCO) system in air: The primary crystallization phase field of the 2212 phase and the effect of silver addition SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SOLID-SOLUTION; CRYSTAL-CHEMISTRY; SUPERCONDUCTING PROPERTIES; BI2SR2CACU2O8 CERAMICS; TEXTURE FORMATION; TAPES; TEMPERATURE; AG; STOICHIOMETRY; REGION AB The subsolidus and primary crystallization phase field of the "2212" (Bi:Sr:Ca:Cu) phase in the BSCCO system have been investigated. At 830 degrees C, this phase was observed to be in equilibrium with ten phases. Sixteen four-phase equilibrium regions that surround the 2212 phase have been identified at this temperature. The melting events associated with these four-phase regions were studied with differential thermal analysis, quenching experiments, and wicking experiments, in which samples of the liquid for analysis were absorbed by capillary action. The melt compositions were obtained by using quantitative energy-dispersive X-ray spectrometry. The 2212 phase melts incongruently, beginning at similar to 825 degrees C. Its primary crystallization held encompasses a compositional range of 24-42 mol% BiO1.5 7-33 mol% SrO, 2-27 mol% CaO, and 19-43 mol% CuO, The compositions of melts in equilibrium with the 2212 phase were mostly on the calcium-deficient side of the 2212 solid solution. An approximate polygonal model of the 2212 primary crystallization field has been presented. The addition of silver depresses the melting temperatures in the vicinity of the 2212 phase, from 4 degrees C to 22 degrees C, Silver entered the melt at a saturation level of 2-8 mol%, In the more copper-rich liquids, silver replaced some of the copper, which resulted in a shift of the 2212 crystallization field away from the copper oxide corner. C1 NIST, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. RP Wong-Ng, WK (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 64 TC 27 Z9 27 U1 0 U2 2 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUL PY 1998 VL 81 IS 7 BP 1829 EP 1838 PG 10 WC Materials Science, Ceramics SC Materials Science GA 100UH UT WOS:000074833400015 ER PT J AU Edson, JB Fairall, CW AF Edson, JB Fairall, CW TI Similarity relationships in the marine atmospheric surface layer for terms in the TKE and scalar variance budgets SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID INERTIAL-DISSIPATION METHOD; AIR-SEA FLUXES; CONVECTIVE BOUNDARY-LAYER; INDEX-STRUCTURE PARAMETER; TURBULENT KINETIC-ENERGY; LATENT-HEAT FLUX; WIND STRESS; REFRACTIVE-INDEX; OPEN-OCEAN; WATER-VAPOR AB Measurements of the momentum, heat, moisture, energy, and scalar variance fluxes are combined with dissipation estimates to investigate the behavior of marine surface layer turbulence. These measurements span a wide range of atmospheric stability conditions and provide estimates of z/L between -8 and 1. Second- and third-order velocity differences are first used to provide an estimate of the Kolmogorov constant equal to 0.53 +/- 0.04. The fluxes and dissipation estimates are then used to provide Monin-Obukhov (MO) similarity relationships of the various terms in the turbulent kinetic energy (TKE) and scalar variance (SV) budgets. These relationships are formulated to have the correct limiting forms in extremely stable and convective conditions. The analyses concludes with a determination of updated dimensionless structure function parameters for use with the inertial-dissipation flux method. The production of TKE is found to balance its dissipation inconvective conditions and to exceed dissipation by up to 17% in near-neutral conditions. This imbalance is investigated using the authors' measurements of the energy flux and results in parameterizations for the energy flux and energy transport term in the TKE budget. The form of the dimensionless energy transport and dimensionless dissipation functions are very similar to previous parameterizations. From these measurements, it is concluded that the magnitude of energy transport (a loss of energy) is larger than the pressure transport (a gain of energy) in slightly unstable conditions. The dissipation of SV is found to closely balance production-in near-neutral conditions. However, the SV budget can only be balanced in convective conditions by inclusion of the transport term. The SV transport term is derived using our estimates of the flux of SV and the derivative approach. The behavior of the derived function represents a slight loss of SV in near-neutral conditions and a gain in very unstable conditions. This finding is consistent with previous investigations. The similarity between these functions and recent overland results further suggests that experiments are generally above the region where wave-induced fluctuations influence the flow. The authors conclude that MO similarity theory is valid in the marine surface layer as long as it is applied to turbulence statistics taken above the wave boundary layer. C1 Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NOAA, Envirnom Technol Lab, Boulder, CO USA. RP Woods Hole Oceanog Inst, MS 10,98 Water St, Woods Hole, MA 02543 USA. EM jedson@whoi.edu NR 94 TC 104 Z9 108 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1998 VL 55 IS 13 BP 2311 EP 2328 DI 10.1175/1520-0469(1998)055<2311:SRITMA>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZZ230 UT WOS:000074708600005 ER PT J AU Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM AF Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM TI Hydrazine - an excellent optically pumped far-infrared lasing gas: review SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID LASER LINES; FREQUENCY MEASUREMENTS; 9-MU-M; N2H4 AB We summarize the 194 far-infrared lasing lines of hydrazine: 7 new lines, 144 lines that we reported recently, and 43 lines reported by other authors. Fewer than 5% of the 43 previously reported lines had wavelengths shorter than 200 mu m, but 82% of our 134 lines (127 and 7 new), discovered in cw (CO2)-C-12-O-16-laser-pumped hydrazine, were shorter than 200 mu m; the shortest was at 49.2 mu m Of the 194 lines now known in hydrazine, 150 have been frequency measured. We present the pump line, the pump offset from the CO2 line center, the far-infrared wavelength and frequency, the optimum pressure, the relative intensity, and the relative polarization of each line. (C) 1998 Optical Society of America. C1 Univ Estadual Campinas, Inst Fis Gleb Wataghin, Dept Elect Quant, BR-13083970 Campinas, SP, Brazil. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Vasconcellos, ECC (reprint author), Univ Estadual Campinas, Inst Fis Gleb Wataghin, Dept Elect Quant, BR-13083970 Campinas, SP, Brazil. RI Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 14 TC 12 Z9 12 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUL PY 1998 VL 15 IS 7 BP 1839 EP 1849 DI 10.1364/JOSAB.15.001839 PG 11 WC Optics SC Optics GA ZZ034 UT WOS:000074688700002 ER PT J AU Robey, SW AF Robey, SW TI Interfacial reaction effects in the growth of MgO on GaAs(001) by reactive molecular beam epitaxy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID PULSED LASER DEPOSITION; BUFFER LAYERS; THIN-FILM; GAAS; HYDROGEN AB MgO has important potential uses as a buffer layer for growth of perovskite and related oxides on GaAs. Equilibrium thermochemical data indicate MgO will be stable against interfacial reaction with GaAs but, under molecular beam epitaxy growth conditions, kinetic limitations can increase the probability of an undesired Mg or O reaction with the substrate and influence epitaxial growth. III situ reflection high-energy electron diffraction and Auger spectroscopy were combined with ex situ atomic farce microscopy to study the potential for nonequilibrium processes to affect MgO growth on GaAs (001) by reactive molecular beam epitaxy. Under oxygen poor conditions, Mg reacts with GaAs to form an epitaxial phase with a cubic structure and a lattice constant of 0.62 +/- 0.01 nm. The growth mode is highly three-dimensional, producing a rough surface morphology. This phase is unstable to subsequent oxidation, which leads to segregation of Mg to the surface to form a polycrystalline MgO overlayer. Three-dimensional growth of the reaction product is inhibited by oxygen pressures providing a Mg-to-O-2 flux ratio on the order of 2, for growth temperatures at 700 K. However, the epitaxial-quality of MgO is still degraded at these oxygen pressures suggesting that, close to stoichiometric MgO conditions, the Mg-GaAs reaction still influences the growth of epitaxial MgO. [S0734-2101(98)06504-X]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Robey, SW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM srobey@enh.nist.gov RI Schaff, William/B-5839-2009 NR 17 TC 12 Z9 12 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1998 VL 16 IS 4 BP 2423 EP 2428 DI 10.1116/1.581413 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 101CU UT WOS:000074852700064 ER PT J AU Silvestre, C Thompson, P Jernigan, G Simons, D AF Silvestre, C Thompson, P Jernigan, G Simons, D TI Boron incorporation with and without atomic hydrogen during the growth of doped layers on Si(100) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID MOLECULAR-BEAM EPITAXY; SCANNING-TUNNELING-MICROSCOPY; CHEMICAL-VAPOR-DEPOSITION; SILICON(001) SURFACE; MORPHOLOGY; STEPS AB Solid source molecular beam epitaxy Si growths were done with and without atomic hydrogen (AH) to investigate the impact of AH on B segregation and activation. A series of 3 or 50 nm thick B-doped Si layers separated by 200 nm of undoped Si were grown at 0.1 nm/s on Si(100) substrates. In separate experiments, 10(-4) Pa of AH was applied after (at 500, 600, and 710 degrees C) or during (at 710 degrees C) the 3 nm B-doped layer to determine if AH affected segregation. AH was applied before the 50 nm B-doped layer to observe if AH increased B activation between 600 and 800 degrees C. It was found that application of AH after the growth of the 3 nm B-doped layer had no effect on B segregation through 600 degrees C and increased B segregation at 710 degrees C, as measured by secondary ion mass spectrometry (SIMS). Application of AH during B-doped Si layer growth had no effect on B segregation. Application of 10(-3) Pa of AH for 100 s prior to growth of the 50 nm B-doped layer improved surface order, as measured by low energy electron diffraction, and, at T greater than or equal to 700 degrees C, increased B activation, as measured by spreading resistance profilometry (SRP). The differences between the SIMS and SRP data are postulated to be due to two forms of B: one electrically active and the other electrically inactive. The electrically inactive form is modeled by two paired B atoms on adjacent substitutional sites. [S0734-2101(98)07304-7]. C1 USN, Res Lab, Div Elect Sci & Technol, Washington, DC 20375 USA. NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Silvestre, C (reprint author), USN, Res Lab, Div Elect Sci & Technol, Code 6812, Washington, DC 20375 USA. NR 24 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1998 VL 16 IS 4 BP 2619 EP 2624 DI 10.1116/1.581414 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 101CU UT WOS:000074852700095 ER PT J AU Stranick, SJ Richter, LJ Cavanagh, RR AF Stranick, SJ Richter, LJ Cavanagh, RR TI High efficiency, dual collection made near-field scanning optical microscope SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID TUNNELING MICROSCOPE; SHEAR-FORCE; FIBER TIP; IMPLEMENTATION; RESOLUTION; ARTIFACTS; DESIGN AB We have developed a near-field scanning optical microscope that provides simultaneous transmission and reflection mode measurements while concurrently recording a topograph of the sample surface. In this microscope design, an ellipsoidal cavity is used to collect and reimage the light reflected from a near-field optic. Reimaging of the near-field optic away from the mechanical components of the microscope eliminates any hindrance that they would otherwise cause. The near-field optical microscope configuration described in this article allows for the efficient, symmetric collection of reflected and transmitted Light. This instrumental design has been optimized for chemical problems that require molecular characterization on the nanometer scale. Images of similar to 100 nm Au particles demonstrate the utility of this instrument. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Stranick, SJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. EM Stephan.Stranick@nist.gov RI Richter, Lee/N-7730-2016 OI Richter, Lee/0000-0002-9433-3724 NR 21 TC 18 Z9 18 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1998 VL 16 IS 4 BP 1948 EP 1952 DI 10.1116/1.590113 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 110LN UT WOS:000075381400031 ER PT J AU Wu, WL Wallace, WE AF Wu, WL Wallace, WE TI Microroughness of polymer thin films studied by total-reflection x-ray fluorescence and atomic force microscopy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID FLAT-PANEL DISPLAYS; SPINODAL DECOMPOSITION; PHASE-SEPARATION; ALIGNMENT; POLYIMIDE; ORIENTATION; BLEND AB The surface roughness of polymer thin films supported on nickel-coated silicon substrates was analyzed by angle-dependent total-reflection x-ray fluorescence (TXRF) in conjunction with atomic force microscopy (AFM). For highly rubbed polystyrene (PS) surfaces (500 cm rubbing length at a load of 2 g/cm(2) over a velour cloth) displaying sharp grooves and ridges, the TXRF showed no significant change while the AFM results revealed an anisotropic 6.08 nm root-mean-square roughness with an average peak-to-peak distance of 170 nm. These results were compared to the isotropic, gradually varying sinusoidal surface roughness of phase-separated polystyrene/poly(vinyl methyl ether) blend thin films. The AFM results were very similar to the results from the rubbed PS in terms of root-mean-square roughness and average peak-to-peak distance; however, the TXRF results revealed enhanced nickel fluorescence at incident angles smaller than the polymer critical angle for reflection. This discrepancy highlights some of the qualitative differences in surface topography between rubbed and phase-separated polymer thin films, and demonstrates the utility-of angle-dependent TXRF to study thin film roughness and planarity. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Wu, WL (reprint author), Natl Inst Stand & Technol, Div Polymers, Bldg 224,Room B320, Gaithersburg, MD 20899 USA. NR 16 TC 16 Z9 17 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1998 VL 16 IS 4 BP 1958 EP 1963 DI 10.1116/1.590115 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 110LN UT WOS:000075381400033 ER PT J AU Robey, SW AF Robey, SW TI Anisotropic microstructure development during the reaction of Mg with GaAs SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 25th Annual Conference on the Physics and Chemistry of Semiconductor Interfaces CY JAN 18-22, 1998 CL SALT LAKE CITY, UTAH ID EPITAXIAL-GROWTH; INITIAL-STAGES; ISLANDS; SI; STRAIN; DISLOCATIONS; TRANSITION; MORPHOLOGY; NUCLEATION; SI(001) AB Reaction of Mg with the GaAs(001) surface occurs at substrate temperatures above 550 K and leads to three-dimensional (3D) growth of an epitaxial, cubic reaction phase with a lattice constant of 0.62 +/- 0.02 nm, 9% larger than GaAs. The resulting anisotropic, 3D heteroepitaxial microstructure was studied using in situ electron diffraction and Auger spectroscopy and ex situ atomic force microscopy (AFM). Three-dimensional structures develop that are elongated along the GaAs[110] direction with aspect ratios (length to width) up to 20. These structures appear to be composed of isotropic islands from which elongated, tapered ridges extend in one direction along [110]. Analysis of AFM images and size distributions suggest a critical size for the initiation of ridge growth. We speculate that these structures develop in response to misfit strain in the reaction phase. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Robey, SW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM steven.robey@nist.gov NR 26 TC 1 Z9 1 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1998 VL 16 IS 4 BP 2413 EP 2416 DI 10.1116/1.590183 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 110LN UT WOS:000075381400110 ER PT J AU Titov, VV Synolakis, CE AF Titov, VV Synolakis, CE TI Numerical modeling of tidal wave runup SO JOURNAL OF WATERWAY PORT COASTAL AND OCEAN ENGINEERING-ASCE LA English DT Article ID NANSEI-OKI EARTHQUAKE; SOLITARY WAVES; CIRCULAR ISLAND; PLANE BEACHES; ROUGH SLOPES; FIELD SURVEY; TSUNAMI; BREAKING; NONBREAKING; REFLECTION AB A numerical solution for the 2 + 1 (long-shore and onshore propagation directions and time) nonlinear shallow-water wave equations, without friction factors or artificial viscosity is presented. The models use a splitting method to generate two 1 + 1 propagation problems, one in the onshore and the other in longshore direction. Both are solved in characteristic form using the method of characteristics. A shoreline algorithm is implemented, which is the generalization of the earlier 1 + 1 algorithm used in the code VTCS-2. The model is validated using large-scale laboratory data from solitary wave experiments attacking a conical island. The method is applied then to model the 1993 Okushiri, Japan, the 1994 Kuril Island, Russia, and the 1996 Chimbote, Peru tsunamis. It is found that the model can reproduce correctly overland flow and even extreme events such as the 30-m runup and the 20-m/s inundation velocities inferred during field surveys. The results suggest that bathymetric and topographic resolution of at least 150 m is necessary for adequate predictions, while at least 50 m resolution is needed to model extreme events, contrary to intuitive expectations that long waves would not interact with morphological features of such short scales. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ So Calif, Dept Civil Engn, Los Angeles, CA 90089 USA. RP Titov, VV (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. RI Synolakis, Costas/B-3197-2008; OI Synolakis, Costas/0000-0003-0140-5379; Titov, Vasily/0000-0002-1630-3829 NR 51 TC 253 Z9 258 U1 18 U2 45 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-950X J9 J WATERW PORT C-ASCE JI J. Waterw. Port Coast. Ocean Eng.-ASCE PD JUL-AUG PY 1998 VL 124 IS 4 BP 157 EP 171 DI 10.1061/(ASCE)0733-950X(1998)124:4(157) PG 15 WC Engineering, Civil; Engineering, Ocean; Water Resources SC Engineering; Water Resources GA ZU611 UT WOS:000074215400001 ER PT J AU Anulacion, BF Myers, MS Willis, ML Collier, TK AF Anulacion, BF Myers, MS Willis, ML Collier, TK TI Quantitation of CYP1A expression in two flatfish species showing different prevalences of contaminant-induced hepatic disease SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 9th International Symposium on Responses of Marine Organisms to Pollutants (PRIMO 9) CY APR 27-30, 1997 CL BERGEN, NORWAY ID EXPOSURE; FISH AB English sole (Pleuronectes vetulus) and starry flounder (Platichthys stellatus) are two sympatric flatfish species which show markedly different responses to chemical contaminant exposure. Whereas English sole develop hepatic neoplasms, the prevalences of which are strongly linked to exposure to polycyclic aromatic hydrocarbons (PAHs), evidence of neoplasia is virtually nonexistent in starry flounder, even those residing in areas with very high levels of PAH in the sediments. Because PAHs are activated to genotoxic forms by the action of cytochrome P450 1A (CYP1A) in teleosts, we are examining the hypothesis that variation in the hepatic expression of this major inducible cytochrome P450 isozyme may contribute to the differential contaminant response. These two species were captured in the Duwamish Waterway, a contaminated area of Puget Sound, Washington. Catalytic activity of CYP1A [determined as aryl hydrocarbon hydroxylase (AHH) activity] was measured in the liver to quantitatively assess the relative induction of CYP1A in these two species, and AHH activity was significantly higher in English sole than in starry flounder (p = 0.015). Cellular expression of CYP1A was determined by immunohistochemical localization of tissues, using an avidin-biotin peroxidase complex method with polyclonal rabbit anti-cod CYP1A. The results showed a markedly reduced expression of CYP1A in hepatocytes of starry flounder, which is consistent with the apparent resistance of this species to the development of hepatocellular neoplasia. This reduced expression of CYP1A in hepatocytes of contaminant-exposed fish was previously seen in oyster toadfish from the Elizabeth River, Virginia, and this species is also apparently resistant to hepatocellular neoplasia. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Anulacion, BF (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 7 TC 9 Z9 10 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD JUL-DEC PY 1998 VL 46 IS 1-5 BP 7 EP 11 DI 10.1016/S0141-1136(98)00001-4 PG 5 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 117WR UT WOS:000075806100003 ER PT J AU Myers, MS French, BL Reichert, WL Willis, ML Anulacion, BF Collier, TK Stein, JE AF Myers, MS French, BL Reichert, WL Willis, ML Anulacion, BF Collier, TK Stein, JE TI Reductions in CYP1A expression and hydrophobic DNA adducts in liver neoplasms of English sole (Pleuronectes vetulus): Further support for the 'resistant hepatocyte' model of hepatocarcinogenesis SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 9th International Symposium on Responses of Marine Organisms to Pollutants (PRIMO 9) CY APR 27-30, 1997 CL BERGEN, NORWAY ID PAROPHRYS-VETULUS; HEPATIC-LESIONS; IMMUNOHISTOCHEMICAL LOCALIZATION; BENTHIC FISH; MARINE FISH; PUGET-SOUND; RAT; WASHINGTON; ISOZYMES; EXPOSURE AB Our recent studies have investigated the applicability of the 'resistance to cytotoxicity' paradigm for chemically induced hepatocarcinogenesis in rats and mice to liver neoplasia in wild English sole (Pleuronectes vetulus). Sole resident at polycyclic aromatic hydrocarbon (PAH)-contaminated sites, such as the Duwamish Waterway in Puget Sound, Washington, exhibit high prevalences of hepatic neoplasms and precursor lesions related to the histogenesis of neoplasms. Previous immunohistochemical studies ill English sole show a consistent reduction of CYP1A expression, localized with a pc,polyclonal antibody to Atlantic cod CYP1A, in hepatic neoplasms and most preneoplastic foci of cellular alteration. The present study utilized immunohistochemical localization and quantitation of CYP1A expression by image analysis, linked with quantitation of hydrophobic DNA adducts by the P-32-postlabeling method, in hepatocellular neoplasms as compared to matched samples of adjacent non-neoplastic liver tissue from the same fish. All fish were from the Duwamish Waterway in Seattle, Washington. In the eight neoplasms assessed (four hepatocellular adenomas, four hepatocellular carcinomas), there was a significant and nearly parallel reduction in DNA adduct concentrations (56-90%) and levels of CYP1A expression (3-99%) as compared to the adjacent non-neoplastic liver tissue. These findings are consistent with the hypothesis that neoplastic hepatocytes in English sole possess a 'resistant' phenotype in which there is a reduced capacity for CYP1A-mediated activation of genotoxic PAHs to their toxic and carcinogenic intermediates, and a consequent reduction in the formation of covalent, hydrophobic DNA adducts front these reactive intermediates. Published by Elsevier Science Ltd. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Myers, MS (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 22 TC 8 Z9 9 U1 2 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD JUL-DEC PY 1998 VL 46 IS 1-5 BP 197 EP 202 DI 10.1016/S0141-1136(98)00010-5 PG 6 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 117WR UT WOS:000075806100041 ER PT J AU Van Beneden, RJ Rhodes, LD Gardner, GR AF Van Beneden, RJ Rhodes, LD Gardner, GR TI Studies of the molecular basis of gonadal tumors in the marine bivalve, Mya arenaria SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 9th International Symposium on Responses of Marine Organisms to Pollutants (PRIMO 9) CY APR 27-30, 1997 CL BERGEN, NORWAY ID EXPRESSION; PROTEIN; CLONING; CLAMS AB Epizootiological studies of gonadal tumors of Maine soft-shell clams (Mya arenaria) have shown prevalences of over 20% in certain populations in eastern Maine. The etiology of these turners is unknown, and both environmental as well as genetic factors may play a role. In order to investigate the effect of exposure to environmental contaminants, we initiated a short-term Exposure study of M. arenaria to [H-3]tetrachlorodibenzo-p-dioxin ([H-3]TCDD). Gill, digestive gland, foot and gonad were sampled up to two weeks after a 24-h exposure to a low dose (10 parts per trillion or pptr) or high dose (2 000 pptr) of [H-3]TCDD in the water. In the gill, peak concentrations occurred at the beginning of depuration, whereas peak concentrations in the digestive gland and foot were found 12-24 h after exposure. In contrast, tissue concentrations in the gonad increased through the post-exposure period; at two weeks after exposure, [3H]TCDD concentrations were highest in the gonad. Examination of gill and gonad by differential display polymerase chain reaction (ddPCR) identified potential alterations in expression of genes that may bio associated with increased cell cycling (heparan sulfate proteoglycan, E3 ubiquinating enzyme) or translation initiation (p68 RNA helicase/initiation factor eIEF-4A). Histopathological analysis indicated no observable alterations in gonadal or gill tissue from exposed animals. (C) 1998 Elsevier Science Ltd All rights reserved. C1 Univ Maine, Dept Zool, Orono, ME 04469 USA. NW Fisheries Sci Ctr, Seattle, WA 98112 USA. US EPA, Narragansett, RI 02882 USA. RP Van Beneden, RJ (reprint author), Univ Maine, Dept Zool, 5751 Murray Hall, Orono, ME 04469 USA. OI Rhodes, Linda/0000-0003-4995-9426 NR 10 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD JUL-DEC PY 1998 VL 46 IS 1-5 BP 209 EP 213 DI 10.1016/S0141-1136(97)00093-7 PG 5 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 117WR UT WOS:000075806100043 ER PT J AU Collier, TK Johnson, LL Stehr, CM Myers, MS Stein, JE AF Collier, TK Johnson, LL Stehr, CM Myers, MS Stein, JE TI A comprehensive assessment of the impacts of contaminants on fish from an urban waterway SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 9th International Symposium on Responses of Marine Organisms to Pollutants (PRIMO 9) CY APR 27-30, 1997 CL BERGEN, NORWAY ID ENGLISH SOLE AB The Hylebos Waterway, in central Puget Sound ill the state of Washington, is severely contaminated by a variety of organic and inorganic contaminants, Studies in the 1970s had shown that flatfish residing in the Hylebos Waterway, had increased prevalences of several types of toxicopathic liver disease, including neoplasms. In 1994, studies Mere initiated to: (i) determine! if contaminant source control had resulted in improvements in habitat qualify, as determined by prevalences of liver disease in flatfish; (ii) encompass the assessment of reproductive function in flatfish, and (iii) determine whether and to what degree there might be contaminant exposure of juvenile salmonids which migrate through this waterway. The findings show that there have been no appreciable changes in disease prevalences or apparent contaminant exposure of flatfish from this site since the 1970s. Moreover, female flatfish front the Hylebos Waterway are showing evidence of precocious sexual maturation in young animals, and inhibited gonadal development in older fish. The results also showed that two species of juvenile salmon sampled from this site ale being exposed to a urine range of chemical contaminants, and the levels of Exposure are comparable to levels which have previously been shown to cause impaired growth, immunosuppression, and increased mortality following pathogen exposure. These studies, which were done to provide a scientific and legal basis for cleaning up and restoring this degraded habitat, provide an example of how studies of pollutant responses in marine organisms (PRIMO) are being applied to societal and resource manager needs, Published by Elsevier Science Ltd. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Collier, TK (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 8 TC 27 Z9 30 U1 0 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD JUL-DEC PY 1998 VL 46 IS 1-5 BP 243 EP 247 DI 10.1016/S0141-1136(98)00005-1 PG 5 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 117WR UT WOS:000075806100050 ER PT J AU Ballance, LT Pitman, RL AF Ballance, LT Pitman, RL TI Cetaceans of the western tropical Indian Ocean: Distribution, relative abundance, and comparisons with cetacean communities of two other tropical ecosystems SO MARINE MAMMAL SCIENCE LA English DT Article DE Indian Ocean; Arabian Sea; tropical cetacean communities; eastern tropical Pacific; Gulf of Mexico; cetacean-seabird-tuna feeding interactions; Balaenoptera musculus; Physeter macrocephalus; Indopacetus pacificus; Mesoplodon pacificus; Delphinus cf. tropicalis; Stenella attenuata; Stenella longirostris; Stenella coeruleoalba ID DOLPHIN HABITATS; PACIFIC AB we conducted a cetacean survey in the pelagic western tropical Indian Ocean (WTIO) aboard an 85-m research vessel from March to July 1995, covering 9,784 linear km. Using 25x binoculars and line-transect methods, we recorded 589 sightings of 21 species. Stenella longirostris was the most abundant cetacean, in terms of number of individuals sighted, by an order of magnitude above any other species, while Physeter macrocephalus was the most frequently sighted, in terms of number of schools. Twelve species were widespread, seven were rare, and two were localized; our sightings include new distributional records for 12 species. Significant observations included the following: (1) Delphinus cf. tropicalis was abundant off the coast of Oman (16 sightings) and readily distinguishable in the field from D. delphis and D. capensis, (2) Balaenoptera musculus was fairly common and localized in the area of the Maldives (17 sightings), and (3) three sightings were made of an unidentified bottlenose whale tentatively referred to as Indopacetus (i.e., Mesoplodon) pacificus. We recorded 26 mixed-species cetacean schools, 43 schools with which seabirds associated, and 17 schools associated with tuna. Notable among these were mixed aggregations of Stenella attenuata, S. longirostris, yellowfin tuna, and seabirds. The cetacean community of the WTIO was similar to that of the eastern tropical Pacific (ETP) and the Gulf of Mexico (GM) in several respects. First, differences in abundance rank of individual species were small, with the result that common species were common and rare species were rare, regardless of ocean. Second, these differences in abundance were due primarily to differences in encounter rate, which varied with ocean by as much as 3,000%, and less so to school size, which generally varied less than 100%. Third, regardless of ocean, three species comprised the majority of cetaceans in the community, Stenella attenuata, S, longirostris, and S. coeruleoalba, representing 62%-82% of all individuals for all species. However, the rank order of abundance for these three species differed with ocean. Most notably, S. attenuata was abundant in the ETP and GM (abundance rank = 2 and 1, respectively) but much less common in the WTIO (abundance rank = 6). Although habitat preferences for S. attenuata appear to overlap considerably with those of S. longirostris in the ETP, our results suggest there may actually be significant differences between these two species. Detailed analysis of oceanographic correlates of distribution will be necessary in order to understand fully the habitat requirements of these pelagic dolphins, often the most conspicuous elements of tropical cetacean communities around the world. C1 SW Fisheries Sci Ctr, Ecol Program, La Jolla, CA 92037 USA. RP Ballance, LT (reprint author), SW Fisheries Sci Ctr, Ecol Program, 8604 La Jolla Shores Dr, La Jolla, CA 92037 USA. NR 78 TC 48 Z9 70 U1 6 U2 21 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1998 VL 14 IS 3 BP 429 EP 459 DI 10.1111/j.1748-7692.1998.tb00736.x PG 31 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZW533 UT WOS:000074420500002 ER PT J AU Forney, KA Barlow, J AF Forney, KA Barlow, J TI Seasonal patterns in the abundance and distribution of California cetaceans, 1991-1992 SO MARINE MAMMAL SCIENCE LA English DT Article DE California; North Pacific; cetacean; whale; dolphin; porpoise; line transect; aerial survey ship survey; abundance; distribution; seasonality; bootstrap; confidence-interval test ID HUMPBACK WHALES; AERIAL SURVEYS; WATERS AB This study presents a detailed seasonal comparison of the abundance and distribution of cetaceans within 100-150 nmi (185-278 km) of the California coast during 1991 and 1992. The results of a shipboard line-transect survey conducted in July-November 1991 ("summer") were compared to those from aerial line-transect surveys conducted in March-April 1991 and February-April 1992 ("winter"). Using a confidence-interval-based bootstrap procedure, abundance estimates for six of the eleven species included in the comparison exhibited significant (alpha = 0.05) differences between the winter and summer surveys. Pacific white-sided dolphins (Lagenorhynchus obliquidens), Risso's dolphins (Grampus griseus). common dolphins (Delphinus spp.), and northern right whale dolphins (Lissodelphis borealis) were significantly more abundant in winter. The abundance of blue whales (Balaenoptera musculus) and gray whales (Eschrichtius robustus) reflected well-documented migratory patterns. Fin whales (B. physalus) were significantly more abundant during summer. No significant differences in seasonal abundance were identified for Dall's porpoises (Phocoenoides dalli), bottlenose dolphins (Tursiops truncatus), killer whales (Orcinus orca), sperm whales (Physeter macrocephalus), or humpback whales (Megaptera novaeangliae). Significant north/south shifts in distribution were found for Dall's porpoises, common dolphins, and Pacific white-sided dolphins, and significant inshore/offshore differences were identified for northern right whale dolphins and humpback whales. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Forney, KA (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. EM kforney@caliban.ucsd.edu NR 57 TC 66 Z9 72 U1 1 U2 20 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1998 VL 14 IS 3 BP 460 EP 489 DI 10.1111/j.1748-7692.1998.tb00737.x PG 30 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZW533 UT WOS:000074420500003 ER PT J AU Davis, RW Fargion, GS May, N Leming, TD Baumgartner, M Evans, WE Hansen, LJ Mullin, K AF Davis, RW Fargion, GS May, N Leming, TD Baumgartner, M Evans, WE Hansen, LJ Mullin, K TI Physical habitat of cetaceans along the continental slope in the north-central and western Gulf of Mexico SO MARINE MAMMAL SCIENCE LA English DT Article DE cetacean; habitat; Gulf of Mexico ID EASTERN TROPICAL PACIFIC; DOLPHIN GRAMPUS-GRISEUS; OF-MEXICO; SEA; CYCLONE; SHELF; EDDY AB The physical habitat of cetaceans found along the continental slope in the north-central and western Gulf of Mexico was characterized from shipboard sighting data, simultaneous hydrographic measurements, and satellite remote sensing. The study area was encompassed by the longitude of the Florida-Alabama border (87.5 degrees W), the southernmost latitude of the Texas-Mexico border (26.0 degrees N), and the 100-m and 2,000-m isobaths. Shipboard surveys were conducted seasonally for two years from April 1992 to May 1994. A total of 21,350 km of transect was visually sampled in an area of 154,621 km(2). Sighting localities of species in the study area were differentiated most clearly with bottom depth. Atlantic spotted dolphins (Stenella frontalis) were consistently found in the shallowest water on the continental shelf and along the shelf break. In addition, the bottom depth gradient (sea floor slope) was less for Atlantic spotted dolphins than for any other species. Bottlenose dolphins (Tursiops truncatus) were found most commonly along the upper slope in water significantly deeper than that for Atlantic sported dolphins. All the other species and species categories were found over deeper bottom depths; these were Risso's dolphins (Grampus griseus), short-finned pilot whales (Globicephala macrorhynchus), pygmy/dwarf sperm whales (Kogia spp.) rough-toothed dolphins (Steno bredanensis), spinner dolphins (Stenella longivostris), sperm whales (Physeter macrocephalus), striped dolphins (Stenella coevuleoalba), Mesoplodon spp., pantropical spotted dolphins (Stenella attenuata), Clymene dolphins (Stenella clymene) and unidentified beaked whales (Ziphiidae). Risso's dolphins and short-finned pilot whales occurred along the upper slope and, as a subgroup, were significantly different from striped dolphins, Mesoplodon spp., pantropical spotted dolphins, Clymene dolphins, and unidentified beaked whales, which occurred in the deepest water. Pygmy/dwarf sperm whales, rough-toothed dolphins, spinner dolphins, and sperm whales occurred at intermediate depths between these two subgroups and overlapped them. C1 Texas A&M Univ, Texas Inst Oceanog, Galveston, TX 77553 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Stennis Space Ctr, MS 39529 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Charleston, SC 29412 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Pascagoula, MS 39568 USA. RP Davis, RW (reprint author), Texas A&M Univ, Texas Inst Oceanog, Galveston, TX 77553 USA. EM davisr@tamug.tamu.edu NR 67 TC 73 Z9 81 U1 1 U2 17 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1998 VL 14 IS 3 BP 490 EP 507 DI 10.1111/j.1748-7692.1998.tb00738.x PG 18 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZW533 UT WOS:000074420500004 ER PT J AU Lerczak, JA Hobbs, RC AF Lerczak, JA Hobbs, RC TI Calculating sighting distances from angular readings during shipboard, aerial, and shore-based marine mammal surveys SO MARINE MAMMAL SCIENCE LA English DT Article ID CALIFORNIA; ABUNDANCE; DOLPHIN; WHALE C1 NOAA, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, Seattle, WA 98115 USA. RP Lerczak, JA (reprint author), NOAA, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 16 TC 53 Z9 57 U1 2 U2 13 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1998 VL 14 IS 3 BP 590 EP 598 DI 10.1111/j.1748-7692.1998.tb00745.x PG 9 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA ZW533 UT WOS:000074420500011 ER PT J AU Xiang, D Hsu, NN Blessing, GV AF Xiang, D Hsu, NN Blessing, GV TI A simplified ultrasonic immersion technique for materials evaluation SO MATERIALS EVALUATION LA English DT Article DE material characterization; line-focus transducer; leaky wave; ultrasonics ID LEAKY LAMB WAVES AB A simplified ultrasonic immersion technique has been developed to measure leaky surface and bulk waves in solid materials by using specially designed lensless, line-focus polyvinylidene fluoride (PVDF) transducers with a large aperture and a short focal distance. Based on a simple methodology, this technique offers precise velocity measurements for these wave types, from which material properties, such as the elastic moduli, can be determined. Directional leaky wave measurements with this technique have been used to detect material anisotropy, as well as to determine the depth and orientation of a surface crack. The effects of plasma-spray conditions on the acoustic properties of sprayed ceramic coatings possessing rough surfaces and porous microstructures have also been measured using this technique. C1 NIST, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. RP Xiang, D (reprint author), NIST, Automated Prod Technol Div, 233-A147, Gaithersburg, MD 20899 USA. NR 14 TC 14 Z9 18 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD JUL PY 1998 VL 56 IS 7 BP 854 EP 859 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 104PA UT WOS:000075021900006 ER PT J AU Messenger, S AF Messenger, S TI Oxygen-isotopic imaging of interplanetary dust. SO METEORITICS & PLANETARY SCIENCE LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM scott.messenger@nist.gov NR 11 TC 5 Z9 5 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD JUL PY 1998 VL 33 IS 4 SU S BP A106 EP A107 PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 117JK UT WOS:000075778000192 ER PT J AU Maslen, PE Faeder, J Parson, R AF Maslen, PE Faeder, J Parson, R TI An effective Hamiltonian for an electronically excited solute in a polarizable molecular solvent SO MOLECULAR PHYSICS LA English DT Article ID DISTRIBUTED MULTIPOLE ANALYSIS; I2-(CO2)N CLUSTER IONS; VB RESONANCE THEORY; VIBRATIONAL-RELAXATION; ULTRAFAST PHOTODISSOCIATION; NONEQUILIBRIUM SOLVATION; RECOMBINATION DYNAMICS; GEMINATE RECOMBINATION; QUANTUM-THEORY; CHARGE FLOW AB An effective Hamiltonian suitable for non-adiabatic molecular dynamics simulations is derived for the low-lying electronic states of a molecular ion interacting with an assembly of polarizable solvent molecules. The Hamiltonian includes both induction and low-frequency dispersion effects. It is based on a molecular treatment of the solvent, but is similar to effective Hamiltonians that treat the solvent as a dielectric continuum. The electronic structure of the solute is described in a space defined by the low-lying electronic states of the isolated molecule, and no assumptions are made about the form of the basis states. The effective Hamiltonian uses distributed multipoles and distributed transition multipoles, both of which may be obtained from ab initio calculations, to describe the charge distribution and polarizability of the molecular ion. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Maslen, PE (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM maslen@bastille.cchem.berkeley.edu; rparson@jila.colorado.edu NR 75 TC 15 Z9 15 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD JUL PY 1998 VL 94 IS 4 BP 693 EP 706 DI 10.1080/002689798167854 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZY609 UT WOS:000074640800011 ER PT J AU Schultz, DM Keyser, D Bosart, LF AF Schultz, DM Keyser, D Bosart, LF TI The effect of large-scale flow on low-level frontal structure and evolution in midlatitude cyclones SO MONTHLY WEATHER REVIEW LA English DT Review ID EXTRATROPICAL MARINE CYCLONE; BAROCLINIC-WAVE; NONDIVERGENT VORTEX; KINEMATIC ANALYSIS; LIFE-CYCLE; AGEOSTROPHIC CIRCULATIONS; ROCKY-MOUNTAINS; FRONTOGENESIS; MODEL; SIMULATION AB Observational and modeling studies documented in the literature indicate that the large-scale flow has an important effect on the structure and evolution of low-level fronts in midlatitude cyclones. The purpose of this paper is to address the role of the large-scale flow on low-level cyclone/frontal structure and evolution through a combined observational and idealized modeling approach. Analyses of two observed cyclone cases embedded in large-scale diffluence and confluence, respectively, are presented to illustrate two possible cyclone/frontal structures and evolutions. Specifically, the cyclone moving into a diffluent, high-amplitude ridge becomes meridionally elongated and possesses a strong meridionally oriented cold front and a weak warm front. The cold front rotates into the warm front, forming an occluded front in the manner of the Norwegian cyclone model, as indicated by the narrowing of the thermal ridge connecting the warm sector to the cyclone center. In contrast, the cyclone moving into confluent, low-amplitude zonal flow becomes zonally elongated and possesses strong zonally oriented warm and bent-back fronts and a weak cold front. The frontal structure in this case is reminiscent of the Shapiro-Keyser cyclone model, exhibiting a fracture between perpendicularly oriented cold and warm fronts (i.e., the so-called frontal T-bone structure). The idealized simulations employ a nondivergent barotropic model in which potential temperature is treated as a passive tracer When a circular vortex acts on an initially zonally oriented baroclinic zone, cold and warm fronts, a frontal fracture. a bent-back front, and eventually a Norwegian-like occlusion develop. When a circular vortex is placed in a diffluent background flow, the vortex and frontal zones become meridionally elongated, and the evolution resembles the Norwegian occlusion with a narrowing thermal ridge. When a circular vortex is placed in a confluent background flow, the vortex and frontal zones become zonally elongated, and the evolution resembles the Shapiro-Keyser model with a frontal fracture, frontal T-bone, and bent-back front. Although the idealized model qualitatively reproduces many of the frontal features found in the observed cyclones analyzed in the present study, one significant difference is that the maximum potential temperature gradient and fronto-genesis along the cold and warm fronts may differ by a factor of 2 or more in the observed cases, but remain equal along the cold and warm fronts throughout the idealized model simulations. Possible reasons for this asymmetry in the strength of the observed cold and warm fronts are discussed. C1 SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA. RP Schultz, DM (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Schultz, David M./A-3091-2010 OI Schultz, David M./0000-0003-1558-6975 NR 102 TC 66 Z9 67 U1 2 U2 16 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1998 VL 126 IS 7 BP 1767 EP 1791 DI 10.1175/1520-0493(1998)126<1767:TEOLSF>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 102FU UT WOS:000074914400002 ER PT J AU Romero, R Ramis, C Alonso, S Doswell, CA Stensrud, DJ AF Romero, R Ramis, C Alonso, S Doswell, CA Stensrud, DJ TI Mesoscale model simulations of three heavy precipitation events in the western Mediterranean region SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTIVE PARAMETERIZATION; NUMERICAL SIMULATIONS; MESO-BETA; VEGETATION; INTERPOLATION; PREDICTION; SYSTEMS; CLOUDS; SEA AB A mesoscale numerical model with parameterized moist convection is applied to three cases involving heavy rainfall in the western Mediterranean region. Forecast precipitation fields, although not perfect when compared to the observations of rainfall, appear to have sufficient information to be considered useful forecasting guidance. The results illustrate that a good simulation for this type of event in a region with complex topography is strongly dependent on a good initialization and prediction of the low-level flow and water vapor distribution. For two of the cases that have a marked synoptic-scale contribution, the simulations give reasonably accurate predictions of the precipitation distribution, although the amounts are generally underestimated. The third case exhibits relatively subtle synaptic-scale forcing and is dominated by isolated convective storms (mostly over the sea) that also produced severe thunderstorms (including tornadoes), and the prediction of precipitation is not as promising. Overall, the results are encouraging in terms of potential application of mesoscale models operationally in the western Mediterranean region. Additional experiments beyond the "control" simulations have been performed to isolate the influence of orography and water vapor flux from the Mediterranean Sea on the model simulations. This factor separation indicates that both effects can be important contributors to a successful forecast. Suggestions are offered for future efforts in pursuing the application of mesoscale models to this forecast problem. C1 NOAA, ERL, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Balearic Isl, Meteorol Grp, Dept Phys, Palma de Mallorca, Spain. RP NOAA, ERL, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. EM doswell@nssl.noaa.gov RI Doswell III, Charles/E-7662-2010 NR 43 TC 40 Z9 40 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1998 VL 126 IS 7 BP 1859 EP 1881 DI 10.1175/1520-0493(1998)126<1859:MMSOTH>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 102FU UT WOS:000074914400006 ER PT J AU Yucel, I Shuttleworth, WJ Washburne, J Chen, F AF Yucel, I Shuttleworth, WJ Washburne, J Chen, F TI Evaluating NCEP eta model-derived data against observations SO MONTHLY WEATHER REVIEW LA English DT Article ID SURFACE FLUXES; CONVECTION; COORDINATE; HYDROLOGY; SYSTEM AB Data derived at the National Centers for Environmental Prediction via four-dimensional data assimilation using the Era Model were evaluated against surface observations from two observational arrays, one located in the semihumid, continental climate of Oklahoma and Kansas and the second in the semiarid climate of southern Arizona. Comparison was made for the period of the Global Energy Water-cycle Experiment Continental-scale International Project's "GIST" dataset in 1994 and their "ESOP-95" dataset in 1995, and for the months of March and May in 1996. Coding errors in the Eta Model's postprocessor used to diagnose near-surface temperature and humidity are shown to have compromised the GIST and ESOP-95 near-surface data. A procedure was devised to correct the GIST and ESOP-95 near-surface fields by mimicking the corrected code used in the Era Model since January 1996. Comparison with observations revealed that modeled surface solar radiation is significantly overestimated except in clear-sky conditions. This discrepancy in cloudy-sky solar radiation was altered little by the substantial January 1996 revisions to Era Model physics, but the revisions are shown to have greatly improved the model's ability to capture daily and seasonal variations in near-surface air temperature, specific humidity, and wind speed. The poorly modeled surface radiation complicates evaluation of modeled surface energy fluxes, but comparison with observations suggests that the modeled daytime Bowen ratio may be systematically high. This study clearly demonstrates the strong sensitivity of model-calculated, near-surface variables to the physics used to describe surface interactions in the data assimilation model. To mitigate against this and to aid intercomparisons between other data, it is recommended that model-derived data always include sufficient information to allow potential users to recalculate the extrapolation to the surface using a user-defined model of surface-atmosphere exchanges. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Environm Modeling Ctr, Camp Springs, MD USA. RP Shuttleworth, WJ (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Bldg 11, Tucson, AZ 85721 USA. RI Chen, Fei/B-1747-2009 NR 26 TC 25 Z9 26 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1998 VL 126 IS 7 BP 1977 EP 1991 DI 10.1175/1520-0493(1998)126<1977:ENEMDD>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 102FU UT WOS:000074914400011 ER PT J AU Douglas, MW Valdez-Manzanilla, A Cueto, RG AF Douglas, MW Valdez-Manzanilla, A Cueto, RG TI Diurnal variation and horizontal extent of the low-level jet over the northern Gulf of California SO MONTHLY WEATHER REVIEW LA English DT Article ID MARITIME TROPICAL AIR; MONSOON; CLIMATOLOGY; AMERICA AB This note describes aspects of the diurnal variation and geographical location of the summertime low-level jet over the Gulf of California, based on wind soundings made at two sites near the northern end of the gulf during a two-week summer field program in 1995. The low-level wind observations from Puerto Penasco, a site along the northern shore of the gulf, showed a strong diurnal cycle decreasing in amplitude to near 0 by the 1800-m altitude. A weaker, but deeper diurnal cycle was observed at Mexicali, an inland site some 200 km west-northwest of Puerto Penasco. The strongest winds were observed at the coastal site; the observations suggest that the strongest southerly winds in the northern gulf lie closer to the eastern shore of the gulf. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Inst Mexicano Tecnol Agua, Jiutepec, Morelos, Mexico. Univ Autonoma Baja California, Mexicali 21100, Baja California, Mexico. RP Douglas, MW (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 16 TC 31 Z9 32 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1998 VL 126 IS 7 BP 2017 EP 2025 DI 10.1175/1520-0493(1998)126<2017:DVAHEO>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 102FU UT WOS:000074914400015 ER PT J AU Dunn, RW Reed, TAW Copeland, RD Frye, CA AF Dunn, RW Reed, TAW Copeland, RD Frye, CA TI The nitric oxide synthase inhibitor 7-nitroindazole displays enhanced anxiolytic efficacy without tolerance in rats following subchronic administration SO NEUROPHARMACOLOGY LA English DT Article DE anxiety; benzodiazepines; nitric oxide; elevated plus-maze ID ELEVATED PLUS-MAZE; 7-NITRO INDAZOLE; ANXIETY AB The nitric oxide synthase inhibitor 7-nitroindazole (7-NI) dose-dependently (3.0-30.0 mg/kg) displayed anxiolytic activity, as measured by an increase in open arm exploration time in the elevated plus-maze (EPM), following intraperitoneal (i.p.) administration in rats. Acute administration of 7-NI at 30.0 mg/kg significantly (P < 0.05) increased open arm exploration time by 176% compared to vehicle control, similar to the benzodiazepine diazepam at 1.0 and 3.0 mg/kg (+ 191 and + 200%, respectively). However, 39 h following subchronic 5-day administration of diazepam twice daily (bid) at 3.0 mg/kg, diazepam was devoid of anxiolytic activity at 1.0 mg/kg, as measured by no difference in open arm exploration time compared to vehicle control, while the 3.0 mg/kg dose still produced a significant (P < 0.05) 175% increase in open arm exploration time. In contrast, following subchronic administration of 7-NI (30.0 mg/kg, bid), a significant (P < 0.01) enhancement in open arm exploration time was observed at 30.0 mg/kg (+ 665% compared to control). Therefore, inhibition of nitric oxide synthase by 7-NI resulted in anxiolysis similar to diazepam following acute administration in the EPM. However, following subchronic administration, unlike diazepam which showed an attenuation of anxiolytic activity, 7-NI displayed enhanced anxiolytic efficacy and was devoid of tolerance. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 CETS, NOS, Old Lyme, CT 06371 USA. Connecticut Coll, Neurosci Program, New London, CT 06320 USA. Connecticut Coll, Dept Psychol, New London, CT 06320 USA. RP Dunn, RW (reprint author), CETS, NOS, POB 894, Old Lyme, CT 06371 USA. NR 20 TC 56 Z9 56 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0028-3908 J9 NEUROPHARMACOLOGY JI Neuropharmacology PD JUL PY 1998 VL 37 IS 7 BP 899 EP 904 DI 10.1016/S0028-3908(98)00076-8 PG 6 WC Neurosciences; Pharmacology & Pharmacy SC Neurosciences & Neurology; Pharmacology & Pharmacy GA 120MB UT WOS:000075959200007 PM 9776385 ER PT J AU Kepa, H Goldman, KI Giebultowicz, TM Majkrzak, CF Springholz, G Krenn, H Holl, S Schinagel, F Bauer, G AF Kepa, H Goldman, KI Giebultowicz, TM Majkrzak, CF Springholz, G Krenn, H Holl, S Schinagel, F Bauer, G TI Antiferromagnetic phase transition and interlayer spin correlations in short-period EuTe/PbTe superlattices SO PHYSICA E LA English DT Article; Proceedings Paper CT 8th International Conference on Modulated Semiconductor Structures CY JUL 14-18, 1997 CL UNIV CA, SANTA BARBARA, CALIFORNIA HO UNIV CA DE antiferromagnetic superlattices; magnetization; neutron diffraction; EuTe/PbTe ID LAYER AB Neutron diffraction and magnetization studies of short-period antiferromagnetic (AF) semiconducting (1 1 1) EuTe/PbTe superlattices are presented. Due to the symmetry-breaking lattice mismatch strain, only a single AF configuration forms in the EuTe layers, instead of four allowed by symmetry in bulk EuTe. The strain and the finite layer thickness also lead to a strong shift in the Neel temperature. Neutron-diffraction spectra exhibit pronounced patterns of satellites, indicating spin correlations between successive EuTe layers separated by PbTe layers, and the transfer of magnetic interactions across the diamagnetic spaces. Experiments on samples with doped PbTe layers and in external magnetic fields rule out that the coupling is caused by any of the mechanisms known to occur in metallic superlattices. Hence, our data strongly suggest the existence of a new interlayer coupling mechanism. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oregon State Univ, Dept Phys, Corvallis, OR 97331 USA. NIST, Gaithersburg, MD 20899 USA. Johannes Kepler Univ, Inst Halbleiterfys, A-4040 Linz, Austria. RP Giebultowicz, TM (reprint author), Oregon State Univ, Dept Phys, Corvallis, OR 97331 USA. NR 8 TC 11 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD JUL PY 1998 VL 2 IS 1-4 BP 399 EP 403 DI 10.1016/S1386-9477(98)00082-4 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 110LT UT WOS:000075383500082 ER PT J AU Mirin, RP Gossard, AC Bowers, JE AF Mirin, RP Gossard, AC Bowers, JE TI Characterization of InGaAs quantum dot lasers with a single quantum dot layer as an active region SO PHYSICA E LA English DT Article; Proceedings Paper CT 8th International Conference on Modulated Semiconductor Structures CY JUL 14-18, 1997 CL UNIV CA, SANTA BARBARA, CALIFORNIA HO UNIV CA DE quantum dot lasers; Rayleigh scattering ID MOLECULAR-BEAM EPITAXY; GROWTH; GAAS; THRESHOLD; ISLANDS; OPERATION AB Quantum dot lasers with an active region consisting of just a single quantum dot layer have been grown using molecular beam epitaxy and characterized from 80 to 300 K. The quantum dot lasers lase from excited states over the entire temperature range. The characteristic temperature is 185 +/- 10 K over the temperature range 80-141 K and decreases to 111 +/- 2 K from 141-304 K. The effects of scattering by the quantum dots has also been analyzed and shown to be unimportant in these quantum dot lasers. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Optoelect Mfg Grp, Boulder, CO 80303 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RP Mirin, RP (reprint author), Natl Inst Stand & Technol, Optoelect Mfg Grp, 325 Broadway, Boulder, CO 80303 USA. RI Bowers, John/B-3486-2012; OI Bowers, John/0000-0003-4270-8296; Mirin, Richard/0000-0002-4472-4655 NR 18 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD JUL PY 1998 VL 2 IS 1-4 BP 738 EP 742 DI 10.1016/S1386-9477(98)00151-9 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 110LT UT WOS:000075383500151 ER PT J AU Indelicato, P Mohr, PJ AF Indelicato, P Mohr, PJ TI Coordinate-space approach to the bound-electron self-energy : Coulomb field calculation SO PHYSICAL REVIEW A LA English DT Article ID LAMB SHIFT; BINDING; STATES; HEAVY; ATOMS; IONS AB A formulation for calculating the one-photon self-energy of an electron in an external field completely in coordinate space, described in an earlier paper, is applied to the calculation of the self-energy of an electron in a Coulomb field by two different numerical methods. In one numerical approach, a high-order asymptotic expansion of the Coulomb Green function is employed to accelerate the convergence of the summation over angular momentum. In the other, a term-by-term subtraction of the divergent terms in the summation over angular momentum is employed. The latter method is found to be preferable from the point of view of both simplicity and precision. Numerical results are compared to the results of previous calculations. C1 Ecole Normale Super, CNRS, UA 18, Lab Kastler Brossel, F-75252 Paris 05, France. Univ Paris 06, F-75252 Paris, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Indelicato, P (reprint author), Ecole Normale Super, CNRS, UA 18, Lab Kastler Brossel, Boite 74,4 Pl Jussieu, F-75252 Paris 05, France. RI Indelicato, Paul/D-7636-2011 OI Indelicato, Paul/0000-0003-4668-8958 NR 19 TC 28 Z9 28 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP 165 EP 179 DI 10.1103/PhysRevA.58.165 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500030 ER PT J AU Djuric, N Zhou, S Dunn, GH Bannister, ME AF Djuric, N Zhou, S Dunn, GH Bannister, ME TI Electron-impact dissociative excitation of CDn+ (n=2-5): Detection of light fragment ions D+ and D-2(+) SO PHYSICAL REVIEW A LA English DT Article ID BEAM AB Absolute cross sections are reported for the electron-impact dissociative excitation of the deuterated hydrocarbon ions CDn+ (n=2-5) from threshold to 70 eV using a crossed beams technique. The method focuses on detecting and measuring Light dissociation-product ions from a heavy target. The ion targets are typical of those formed in the discharge ion source, and some may be in excited electronic and/or vibrational states. A common feature of the studied targets was a dominant D+ formation cross section with almost the same absolute value of 2 x 10(-16) cm(2) for all n from 25 to 70 eV. The present measurements are compared with the available data, and for D+ from CD2+ and CD5+ the data agree well with recent results obtained with the storage-ring technique. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Djuric, N (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. OI Bannister, Mark E./0000-0002-9572-8154 NR 20 TC 16 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP 304 EP 308 DI 10.1103/PhysRevA.58.304 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500044 ER PT J AU Deng, L Payne, MG Garrett, WR AF Deng, L Payne, MG Garrett, WR TI Nonlinear frequency conversion with short laser pulses and maximum atomic coherence SO PHYSICAL REVIEW A LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; DISPERSIVE PROPERTIES; GENERATION; HYDROGEN; SYSTEMS AB A perturbation treatment for Raman generation with a combination of long, short, and delayed laser pulses is presented. When the coupling and probe lasers are applied in a counterintuitive sequence, the fast oscillatory contributions to populations and coherence are eliminated by robust adiabatic passage, allowing a much simpler solution to the problem. Such counterintuitive and on-resonance operation allows effective electromagnetically induced transparency to evolve so that the probe laser photons will experience no absorption yet still fully participate in the nonlinear frequency conversion. Consequently, better conversion efficiency should be possible. C1 Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. RI Deng, Lu/B-3997-2012 NR 20 TC 18 Z9 18 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD JUL PY 1998 VL 58 IS 1 BP 707 EP 712 DI 10.1103/PhysRevA.58.707 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZZ998 UT WOS:000074790500091 ER PT J AU Podobedov, VB Weber, A Romero, DB Rice, JP Drew, HD AF Podobedov, VB Weber, A Romero, DB Rice, JP Drew, HD TI Effect of structural and magnetic transitions in La1-xMxMnO3 (M=Sr, Ca) single crystals in Raman scattering SO PHYSICAL REVIEW B LA English DT Article ID PHASE-TRANSITIONS; DOPED LAMNO3; MAGNETORESISTANCE; LA1-XSRXMNO3; TRANSPORT; BACEO3; SRCEO3 AB Polarized Raman spectra of undoped and doped La1-xMxMnO3 single crystals have been studied in the temperature range from 5 to 423 K (M=Sr, Ca). The spectral intensity is mainly related to scattering by optical phonons at q similar to 0 (for x approximate to 0) and the density of vibrational states for x>0.1. Raman spectra from the undoped LaMnO3 structure distorted by the static Jahn-Teller effect are consistent with the orthorhombic D-2h(16), space group. Raman spectra of the doped La1-xMxMnO3 crystals have weakly resolved features and intensities comparable to those of the second-order spectra in cubic media. The anomalies in the phonon spectra of doped crystals were explained by the doping dependence of the ionic radius of a La/Sr site. The most intense B-1g mode in LaMnO3 crystal has an abrupt frequency shift near T-N = 140 K, which corresponds to a paramagnetic to canted-antiferromagnetic phase transition. [S0163-1829(98)06725-3]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Russian Acad Sci, Inst Spect, Troitsk 142092, Moscow Region, Russia. RP Podobedov, VB (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 26 TC 109 Z9 111 U1 0 U2 20 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1998 VL 58 IS 1 BP 43 EP 46 DI 10.1103/PhysRevB.58.43 PG 4 WC Physics, Condensed Matter SC Physics GA ZY633 UT WOS:000074643200012 ER PT J AU MacFarlane, WA Kiefl, RF Dunsiger, S Sonier, JE Chakhalian, J Fischer, JE Yildirim, T Chow, KH AF MacFarlane, WA Kiefl, RF Dunsiger, S Sonier, JE Chakhalian, J Fischer, JE Yildirim, T Chow, KH TI Muon-spin-relaxation studies of the alkali-fulleride superconductors SO PHYSICAL REVIEW B LA English DT Review ID NUCLEAR-MAGNETIC-RESONANCE; FIELD PENETRATION DEPTH; HIGH-TC SUPERCONDUCTORS; ENERGY-GAP; ELECTRONIC-STRUCTURE; II SUPERCONDUCTORS; COHERENCE PEAK; TUNNELING SPECTROSCOPY; ARBITRARY TEMPERATURE; MOLECULAR-DYNAMICS AB Muon-spin-rotation and relaxation experiments have been performed on the alkali-fulleride superconductors: Rb3C60, K3C60, Na2CsC60. A small fraction of the implanted muons form endohedral muonium (Mu@C-60) i.e., a mu(+)e(-) atom on the inside of the C-60 cage. The presence of the unpaired electron on the muon greatly enhances the sensitivity of the muon to scattering from electronic excitations and the resulting muon-spin relaxation. The 1/T-1 spin-relaxation rate of Mu@C-60 in a longitudinal field exhibits a Korringa-like temperature dependence in the normal state, and a small Hebel-Slichter coherence peak followed by activated temperature dependence well below T-c. In Rb3C60 the coherence peak is strongly suppressed by a magnetic field which is well below H-c2. From the activated temperature dependence we obtain estimates of the superconducting energy gap. In addition, spin precession measurements of diamagnetic muons in the vortex state are used to estimate the magnetic penetration depth. In Na2CsC60, we find a quench rate dependence suggesting the existence of two low-temperature metallic phases, only one of which is superconducting. [S0163-1829(98)03725-4]. C1 Univ British Columbia, Canadian Inst Adv Res, Dept Phys, Vancouver, BC V6T 1Z1, Canada. Univ British Columbia, TRIUMF, Vancouver, BC V6T 1Z1, Canada. Univ Penn, Dept Mat Sci, Philadelphia, PA 19104 USA. Univ Penn, Res Struct Matter Lab, Philadelphia, PA 19104 USA. Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Lehigh Univ, Dept Phys, Bethlehem, PA 18015 USA. RP Lab Phys Solides, Bat 510, F-91405 Orsay, France. RI yildirim, taner/A-1290-2009; Chakhalian, Jak/F-2274-2015 NR 138 TC 15 Z9 15 U1 1 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUL 1 PY 1998 VL 58 IS 2 BP 1004 EP 1024 DI 10.1103/PhysRevB.58.1004 PG 21 WC Physics, Condensed Matter SC Physics GA ZZ014 UT WOS:000074686600066 ER PT J AU Thrower, F Martin, R Heintz, R AF Thrower, F Martin, R Heintz, R TI Survival and growth of two stocks of presmolt Chinook salmon held overwinter in marine net-pens with an artificial freshwater lens SO PROGRESSIVE FISH-CULTURIST LA English DT Article ID ONCORHYNCHUS-KISUTCH; SMOLTIFICATION; SEAWATER AB Two hatchery stocks of juvenile spring chinook salmon Oncorhynchus tshawytscha originating from two southeast Alaska rivers were reared in freshwater to an average size of 8-10 g and placed in marine net-pens with an artificial freshwater lens system (AFLS) at four entry times from mid-September to early November 1987. Overwinter survival to May 1988 averaged 83.6% for Unuk River stock and 76.0% for Chickamin River stock and did not differ significantly in the AFLS among the four entry dates. Survival over 24 h differed significantly when entry was directly into 30 parts per thousand seawater. The 24-h plasma sodium levels in the juveniles challenged to either full-strength seawater or marine net-pens with an AFLS were not useful predictors of overwinter survival. Over winter, both stocks grew significantly better in the AFLS than in freshwater. The AFLS appears to be a cost-effective means of substantially increasing smelt production while minimizing freshwater use. C1 Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Thrower, F (reprint author), Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 11 TC 3 Z9 3 U1 0 U2 1 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0033-0779 J9 PROG FISH CULT JI Progress. Fish-Cult. PD JUL PY 1998 VL 60 IS 3 BP 200 EP 205 DI 10.1577/1548-8640(1998)060<0200:SAGOTS>2.0.CO;2 PG 6 WC Fisheries SC Fisheries GA 101YN UT WOS:000074896200005 ER PT J AU Georges, TM Harlan, JA Lee, TN Leben, RR AF Georges, TM Harlan, JA Lee, TN Leben, RR TI Observations of the Florida Current with two over-the-horizon radars SO RADIO SCIENCE LA English DT Article ID OCEAN SURFACE CURRENTS; TRANSPORT AB We show the space and time variability of the Florida Current in the Southern Straits of Florida using imagery derived from measurements made with two high-frequency over-the-horizon (ionospheric) radars. Between March and August 1997, ten surface current maps show how the Florida Current meanders in response to mesoscale eddies propagating eastward through the Straits. Satellite altimetry aids in the interpretation of the radar imagery by showing upstream eddy development in the Gulf of Mexico. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Colorado, Colorado Ctr Astrodynam Res, Boulder, CO 80309 USA. RP Georges, TM (reprint author), NOAA, Environm Technol Lab, R-E-ET1,325 Broadway, Boulder, CO 80303 USA. RI Leben, Robert/F-3792-2010 OI Leben, Robert/0000-0003-1067-9515 NR 16 TC 2 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1998 VL 33 IS 4 BP 1227 EP 1239 DI 10.1029/98RS00420 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 105RZ UT WOS:000075088500035 ER PT J AU Harlan, JA Georges, TM Biggs, DC AF Harlan, JA Georges, TM Biggs, DC TI Comparison of over-the-horizon radar surface-current measurements in the Gulf of Mexico with simultaneous sea truth SO RADIO SCIENCE LA English DT Article AB On June 14, 1995, the U.S. Navy's Relocatable Over-the-Horizon Radar (ROTHR) west of Corpus Christi, Texas, mapped the radial component of ocean surface current with 15-km resolution over a 230,000-km(2) area in the Gulf of Mexico. Concurrently, an oceanographic research vessel measured near-surface currents within part of the area illuminated by the radar, providing an opportunity to compare radar-derived surface currents with in situ sea truth. The R/V Gyre, operated by Texas A&M University, twice traversed the Gulf of Mexico Loop Current while measuring current vectors with an acoustic Doppler current profiler (ADCP). We compared radar-derived currents with currents measured in the uppermost ADCP bin (centered at IO-m depth). Lf only radar data exceeding a quality threshold are considered, the rms difference in the radial currents measured by the two techniques is 27 cm s(-1). This difference most likely reflects the different sampling employed by these instruments, as well as unremoved ionospheric biases in the radar measurements. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. RP Harlan, JA (reprint author), NOAA, Environm Technol Lab, R-E-ET1,325 Broadway, Boulder, CO 80303 USA. NR 14 TC 2 Z9 3 U1 3 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1998 VL 33 IS 4 BP 1241 EP 1247 DI 10.1029/98RS00747 PG 7 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 105RZ UT WOS:000075088500036 ER PT J AU Meitzner, G Bare, SR Parker, D Woo, H Fischer, DA AF Meitzner, G Bare, SR Parker, D Woo, H Fischer, DA TI An in situ x-ray absorption spectroscopic cell for high temperature gas-flow measurements SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID TRANSMISSION EXAFS MEASUREMENTS; INSITU CELL; CATALYSTS; SAMPLES; WATER AB The problem of controlling the temperature, pressure, and atmosphere around a solid sample for x-ray absorption spectroscopy, while accurately positioning it in the x-ray beam, has given rise to a wide range of designs. We describe here a new versatile design that provides excellent temperature control, and good hydrodynamics and corrosion resistance. Briefly, the cell comprises a stainless steel tube beam path, with a wafer sample positioned across the tube. Heat is supplied from an aluminum block that surrounds the tube. Gases for in situ sample treatment are flowed between fittings at the ends of the tube, and the dead volume is less than 0.3 cm(3). (C) 1998 American Institute of Physics. [S0034-6748(98)02907-4] C1 Edge Analyt Inc, Middleton, WI 53562 USA. Dow Chem Co USA, Midland, MI 48674 USA. Exxon Res & Dev Co, Baton Rouge, LA 70821 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Edge Analyt Inc, Middleton, WI 53562 USA. OI Bare, Simon/0000-0002-4932-0342 NR 15 TC 22 Z9 22 U1 2 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1998 VL 69 IS 7 BP 2618 EP 2621 DI 10.1063/1.1148988 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RL UT WOS:000075279200005 ER PT J AU Phillips, WD AF Phillips, WD TI Laser cooling and trapping of neutral atoms SO REVIEWS OF MODERN PHYSICS LA English DT Review ID RESONANCE-RADIATION PRESSURE; BOSE-EINSTEIN CONDENSATION; COLD CESIUM ATOMS; LAMB-DICKE LIMIT; SODIUM ATOMS; OPTICAL MOLASSES; QUANTUM JUMPS; PHOTOASSOCIATIVE SPECTROSCOPY; ULTRACOLD COLLISIONS; QUANTIZED MOTION C1 Natl Inst Stand & Technol, Phys Lab, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Phillips, WD (reprint author), Natl Inst Stand & Technol, Phys Lab, Atom Phys Div, Gaithersburg, MD 20899 USA. NR 125 TC 676 Z9 689 U1 24 U2 122 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD JUL PY 1998 VL 70 IS 3 BP 721 EP 741 DI 10.1103/RevModPhys.70.721 PG 21 WC Physics, Multidisciplinary SC Physics GA 109EG UT WOS:000075307800003 ER PT J AU Frey, HR AF Frey, HR TI Credit where credit is due SO SEA TECHNOLOGY LA English DT Letter C1 NOAA, NODC, Silver Spring, MD 20910 USA. RP Frey, HR (reprint author), NOAA, NODC, Silver Spring, MD 20910 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD JUL PY 1998 VL 39 IS 7 BP 101 EP 101 PG 1 WC Engineering, Ocean SC Engineering GA 105TW UT WOS:000075090500011 ER PT J AU Dryer, M Andrews, MD Aurass, H Deforest, C Galvin, AB Garcia, H Ipavich, FM Karlicky, M Kiplinger, A Klassen, A Meisner, R Paswaters, SE Smith, Z Tappin, SJ Thompson, BJ Watari, SI Michels, DJ Brueckner, GE Howard, RA Koomen, MJ Lamy, P Mann, G Arzner, K Schwenn, R AF Dryer, M Andrews, MD Aurass, H Deforest, C Galvin, AB Garcia, H Ipavich, FM Karlicky, M Kiplinger, A Klassen, A Meisner, R Paswaters, SE Smith, Z Tappin, SJ Thompson, BJ Watari, SI Michels, DJ Brueckner, GE Howard, RA Koomen, MJ Lamy, P Mann, G Arzner, K Schwenn, R TI The solar minimum active region 7978, its X2.6/1B flare, CME, and interplanetary shock propagation of 9 July 1996 SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; MAGNETOHYDRODYNAMIC SIMULATION; DYNAMICAL EVOLUTION; SCINTILLATION; STREAMER; SYSTEM; IPS AB The first X-class flare in four years occurred on 9 July 1996. This X2.6/LB flare reached its maximum at 09:11 UT and was located in active region 7978 (S10 degrees W30 degrees) which was an old-cycle sunspot polarity group. We report the SOHO LASCO/EIT/MDI and SOONSPOT observations before and after this event together with Yohkoh SXT images of the flare, radio observations of the type II shock, and GOES disk-integrated soft X-ray flux during an extended period that included energy build-up in this active region. The LASCO coronagraphs measured a significant coronal mass ejection (CME) on the solar west limb beginning on 8 July at about 09:53 UT. The GOES 8 soft X-ray Aux (0.1-0.8 nm) had started to increase on the previous day from below the A-level background (10(-8) W m(-2)). At the start time of the CME, it was at the mid-B level and continued to climb. This CME is similar to many events which have been seen by LASCO and which are being interpreted as disruption of existing streamers by emerging flux ropes. LASCO and EIT were not collecting data at the time of the X-flare due to a temporary software outage. A larger CME was in progress when the first LASCO images were taken after the flare, Since the first image of the 'big' CME was obtained after the flare's start time, we cannot clearly demonstrate the physical connection of the CME to the flare. However, the LASCO CME data are consistent with an association of the flare and the CME. No eruptive filaments were observed during this event. We used the flare evidence noted above to employ in real time 3 simplified Shock-Time-of-Arrival (STOA) algorithm to estimate the arrival of a weak shock at the WIND spacecraft. We compare this prediction with the plasma and IMF data from WIND and plasma data from the SOHO/CELIAS instrument and suggest that the flare - and possibly the interplanetary consequences of the 'big' CME - was the progenitor of the mild, high-latitude, geomagnetic storm (daily sum of K p = 16+, Ap = 8) on 12 July 1996. We speculate that the shock was attenuated enroute to Earth as a result of interaction with the heliospheric current/plasma sheer. C1 NOAA, Space Environm Ctr, Boulder, CO 80303 USA. Hughes STX NRL, Washington, DC 20375 USA. Inst Astrophys, D-14472 Potsdam, Germany. Stanford Univ, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Boulder, CO 80309 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Birmingham, Birmingham B15 275, W Midlands, England. NASA, Space Applicat Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Commun Res Lab, Tokyo 184, Japan. Astron Spatiale Lab, F-13376 Marseille 12, France. Max Planck Inst Aeron, D-37189 Katlenburg Lindau, Germany. Univ Maryland, College Pk, MD 20742 USA. Astron Inst, Ondrejov Observ, Ondrejov, Czech Republic. Univ Bern, Inst Angew Phys, CH-3012 Bern, Switzerland. Univ Colorado, Denver, CO 80201 USA. SFA Inc, Landover, MD 20785 USA. RP Dryer, M (reprint author), NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RI Galvin, Antoinette/A-6114-2013; Thompson, Barbara/C-9429-2012; Karlicky, Marian/G-9023-2014; xue, yansheng/A-9712-2012 NR 35 TC 33 Z9 33 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUL PY 1998 VL 181 IS 1 BP 159 EP 183 DI 10.1023/A:1016522812668 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 113KL UT WOS:000075550100012 ER PT J AU Miller, AC Powell, CJ Gelius, U Anderson, CR AF Miller, AC Powell, CJ Gelius, U Anderson, CR TI Energy calibration of X-ray photoelectron spectrometers. Part III: Location of the zero point on the binding-energy scale SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE XPS; x-ray photoelectron spectroscopy; calibration; Fermi energy ID NI AB Calibration of the binding energy scale in x-ray photoelectron spectroscopy (XPS) requires location of the zero point. This zero point has previously been identified with the inflection point in the Fermi-edge region of a valence-band photoemission spectrum of nickel. Comparison of photoemission spectra of nickel and silver measured with monochromated x-rays shows that the inflection points near the Fermi edge differ by 45 +/- 5 meV (where the stated uncertainty indicates the standard uncertainty) at an instrumental energy resolution of 0.30 eV, This difference is due to differences in the valence-band densities of states (DOS) of the two metals. Simulations of the Ni photoemission spectrum have been performed based on the DOS calculated by Eckhardt and Fritsche, and the simulated spectrum agrees well with the measured spectrum in the near-edge region. Additional simulations of the Ni photoemission spectrum have been carried out with both monochromated Al x-rays and unmonochromated Mg and Al characteristic x-rays to determine how the Ni near-edge inflection point varies with the energy resolution of the electron energy analyzer in XPS. (C) 1998 John Wiley & Sons, Ltd. C1 Lehigh Univ, Zettlemoyer Ctr Surface Studies, Bethlehem, PA 18015 USA. Univ Uppsala, Dept Phys, S-75121 Uppsala, Sweden. Anderson Mat Evaluat, Baltimore, MD 21227 USA. Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Powell, CJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Chem B-248, Gaithersburg, MD 20899 USA. NR 9 TC 7 Z9 7 U1 0 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD JUL PY 1998 VL 26 IS 8 BP 606 EP 614 DI 10.1002/(SICI)1096-9918(199807)26:8<606::AID-SIA405>3.0.CO;2-8 PG 9 WC Chemistry, Physical SC Chemistry GA 103KJ UT WOS:000075000000008 ER PT J AU Grimshaw, RHJ Ostrovsky, LA Shrira, VI Stepanyants, YA AF Grimshaw, RHJ Ostrovsky, LA Shrira, VI Stepanyants, YA TI Long nonlinear surface and internal gravity waves in a rotating ocean SO SURVEYS IN GEOPHYSICS LA English DT Review ID KORTEWEG-DEVRIES EQUATION; SOLITARY WAVES; MASSACHUSETTS BAY; FINITE DEPTH; SOLITONS; GENERATION; TIDES; FLUID; SEA; CHANNEL AB Nonlinear dynamics of surface and internal waves in a stratified ocean under the influence of the Earth's rotation is discussed. Attention is focussed upon guided waves long compared to the ocean depth. The effect of rotation on linear processes is reviewed in detail as well as the existing nonlinear models describing weakly and strongly nonlinear dynamics of long waves. The influence of rotation on small-scale waves and two-dimensional effects are also briefly considered. Some estimates of the influence of the Earth's rotation on the parameters of real oceanic waves are presented and related to observational and numerical data. C1 Monash Univ, Dept Math, Clayton, Vic 3168, Australia. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Environm Technol Lab, Boulder, CO 80309 USA. Natl Univ Ireland Univ Coll Cork, Dept Appl Math, Cork, Ireland. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603600, Russia. Nizhny Novgorod State Tech Univ, Nizhnii Novgorod, Russia. RP Grimshaw, RHJ (reprint author), Monash Univ, Dept Math, Clayton, Vic 3168, Australia. EM rhjg@wave.maths.monash.edu.au; lostrovsky@etl.noaa.gov; shrira@ucc.ie; yuas@waise.nntu.sci-nnov.ru RI Grimshaw, Roger/J-7855-2013; OI Grimshaw, Roger/0000-0003-0917-3218; Ostrovsky, Lev/0000-0003-2233-1305 NR 74 TC 97 Z9 98 U1 0 U2 17 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-3298 J9 SURV GEOPHYS JI Surv. Geophys. PD JUL PY 1998 VL 19 IS 4 BP 289 EP 338 DI 10.1023/A:1006587919935 PG 50 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 153FF UT WOS:000077821500001 ER PT J AU Joy, L AF Joy, L TI Pore pioneers SO TECHNOLOGY REVIEW LA English DT Letter C1 NIST, Gaithersburg, MD 20899 USA. RP Joy, L (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MASS INST TECHNOL PI CAMBRIDGE PA BUILDING W59, CAMBRIDGE, MA 02139 USA SN 0040-1692 J9 TECHNOL REV JI Technol. Rev. PD JUL-AUG PY 1998 VL 101 IS 4 BP 16 EP 17 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZW088 UT WOS:000074372700023 ER PT J AU Buckel, JA Letcher, BH Conover, DO AF Buckel, JA Letcher, BH Conover, DO TI Effects of a delayed onset of piscivory on the size of age-0 bluefish SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID THE-YEAR BLUEFISH; EARLY-LIFE-HISTORY; POMATOMUS-SALTATRIX; COMPENSATORY GROWTH; LARGEMOUTH BASS; SALVELINUS-ALPINUS; FEEDING HISTORY; ARCTIC CHARR; REEF FISH; RECRUITMENT AB Variation in advection or other physical forces may accelerate or delay arrival of young marine fishes into productive nearshore habitats, thereby affecting the length of the available growing season. The bluefish Pomatomus saltatrix is an oceanic spawner whose juvenile stages, upon entry into estuarine waters, become piscivorous and thereby experience greatly increased growth. Size attained during the growing season may therefore be determined by time of arrival into estuarine habitats. We exposed bluefish recently recruited to an estuary to three diet shift treatments in which test fish were fed adult brine shrimp Artemia sp. for 0, 10, or 20 d before they were switched to piscine prey. Bluefish that had a delayed onset of piscivory were smaller after 40 d of growth, indicating that they did not fully compensate for prior periods of slow growth. These bluefish did exhibit immediate moderate growth compensation (about 6% over 10 d) resulting from increased consumption rates, but relatively low growth efficiencies prevented full recovery of their growth losses. Low growth efficiencies may have resulted from an induced developmental handicap or an energetic penalty for prolonged feeding on an Anemia diet. The timing of age-0 bluefish recruitment into estuarine environments can have a lasting influence on size attained during the first growing season. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. RP Buckel, JA (reprint author), Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, 74 Magruder Rd, Highlands, NJ 07732 USA. NR 46 TC 18 Z9 18 U1 0 U2 5 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 1998 VL 127 IS 4 BP 576 EP 587 DI 10.1577/1548-8659(1998)127<0576:EOADOO>2.0.CO;2 PG 12 WC Fisheries SC Fisheries GA 109XX UT WOS:000075350600005 ER PT J AU Dukhin, AS Goetz, PJ Hackley, V AF Dukhin, AS Goetz, PJ Hackley, V TI Modified log-normal particle size distribution in acoustic spectroscopy SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article ID SUSPENSIONS; EMULSIONS AB The modified log-normal distribution is a smooth continuous distribution depending on four parameters: median size, standard deviation, minimum size and maximum size, This distribution introduced by Kottler [J. Franklin Inst. 250 (1950) 339] and Irani [J. Phys. Chem, 63 (1959) 1603] gives an opportunity to restrict the particle size range. This distribution is asymmetrical on the logarithmic scale of particle sizes. The modified log-normal distribution is especially useful for acoustic spectroscopy because sound attenuation is very sensitive to the presence of large particles. Particles with size above 3 mu m cause significant scattering losses. As a result, sound attenuation spectra show a sharp growth within a sound frequency range 10-100 MHz when large particles are present. The high sensitivity to large particles is a very useful feature of acoustic spectroscopy allowing one to detect these particles. This feature requires a special approach allowing the characterization of large particles with a high accuracy. Regular log-normal distribution tends to overestimate the fraction of large particles and underestimate the median size. Experimental tests have been performed with silicon particles dispersed in water. The particle size distribution has been measured independently by X-ray sedimentation and by an acoustic spectrometer. This test shows that the lognormal distribution provided by the acoustic spectrometer deviates from the sedimentation data. Implementation of the modified log-normal distribution resolves this discrepancy. (C) 1998 Elsevier Science B.V. C1 Pen Kem Inc, Bedford Hills, NY 10507 USA. NIST, Gaithersburg, MD 20899 USA. RP Dukhin, AS (reprint author), Pen Kem Inc, 341 Adams St, Bedford Hills, NY 10507 USA. NR 12 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD JUN 30 PY 1998 VL 138 IS 1 BP 1 EP 9 DI 10.1016/S0927-7757(97)00011-3 PG 9 WC Chemistry, Physical SC Chemistry GA ZV725 UT WOS:000074334800001 ER PT J AU Kelley, EF Jones, GR Germer, TA AF Kelley, EF Jones, GR Germer, TA TI Display reflectance model based on the BRDF SO DISPLAYS LA English DT Article DE flat panel displays; display reflectance model; bidirectional reflectance distribution function AB Many flat panel displays (FPDs) have anti-reflection sur face treatments that differ in character from those of traditional cathode-ray-tube displays. Specular reflection models (mirror-like, producing a distinct image) combined with diffuse (Lambertian) reflection models can be entirely inadequate to characterize the reflection properties of such displays. A third reflection component, called haze, exists between specular and diffuse. Display metrology should account for the haze component of reflection. That is best done using the bidirectional reflectance distribution function (BRDF). The effects of using oversimplified reflectance models are discussed in contrast with a parameterized BRDF. (C) 1998 Elsevier Science B.V. C1 NIST, Gaithersburg, MD 20899 USA. RP Kelley, EF (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 5 TC 20 Z9 20 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0141-9382 J9 DISPLAYS JI Displays PD JUN 30 PY 1998 VL 19 IS 1 BP 27 EP 34 DI 10.1016/S0141-9382(98)00028-6 PG 8 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics SC Computer Science; Engineering; Instruments & Instrumentation; Optics GA ZX995 UT WOS:000074576200004 ER PT J AU Kreider, KG DiMeo, F AF Kreider, KG DiMeo, F TI Platinum/palladium thin-film thermocouples for temperature measurements on silicon wafers SO SENSORS AND ACTUATORS A-PHYSICAL LA English DT Article DE palladium; platinum; rapid thermal processing; silicon; thin-film thermocouples AB A platinum versus palladium thin-film thermocouple system has been established for measuring temperatures on silicon wafers in a rapid thermal processing (RTP) tool. The application includes a silicon wafer with an array of thin-film thermocouples welded to wire thermocouples, used to calibrate radiometric temperature measurements of the RTP tool. The thin-film thermocouples have advantages over present technology using wire thermocouples because the films cause less disturbance of the heat transfer to and from the silicon wafer during periods of high heat flux. High-purity platinum and palladium films have been chosen because of their stability, their resistance to oxidation at high temperatures (to 900 degrees C), and their compatibility with Pt/Pd wire thermocouples. The research effort has concentrated on developing solutions to the adhesion problems for platinum and palladium on silicon; measuring the change in resistance of the films after exposure in air to high temperatures (up to 1050 degrees C); quantifying the drift and hysteresis of the thin-film thermocouples in calibration tests; and determining the effects of composition, stress, and morphology on the Seebeck coefficient. The results of the testing indicate that the Pt/Pd thin-film thermocouples on silicon can perform satisfactorily up to 850 degrees C. We present a discussion of the factors that affect the stability of the films; these include diffusion, chemical reactions, and thermal-mechanical stress, as well as the limitations of this material system. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Proc Measurements Div, Gaithersburg, MD 20899 USA. RP Kreider, KG (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Proc Measurements Div, Gaithersburg, MD 20899 USA. NR 9 TC 37 Z9 39 U1 5 U2 24 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-4247 J9 SENSOR ACTUAT A-PHYS JI Sens. Actuator A-Phys. PD JUN 30 PY 1998 VL 69 IS 1 BP 46 EP 52 DI 10.1016/S0924-4247(97)01747-0 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA ZX446 UT WOS:000074516700009 ER PT J AU McPhaden, MJ Busalacchi, AJ Cheney, R Donguy, JR Gage, KS Halpern, D Ji, M Julian, P Meyers, G Mitchum, GT Niiler, PP Picaut, J Reynolds, RW Smith, N Takeuchi, K AF McPhaden, MJ Busalacchi, AJ Cheney, R Donguy, JR Gage, KS Halpern, D Ji, M Julian, P Meyers, G Mitchum, GT Niiler, PP Picaut, J Reynolds, RW Smith, N Takeuchi, K TI The tropical ocean global atmosphere observing system: A decade of progress SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-SURFACE-TEMPERATURE; EQUATORIAL PACIFIC-OCEAN; NINO-SOUTHERN-OSCILLATION; GENERAL-CIRCULATION MODEL; 1982-1983 EL-NINO; STATISTICAL INTERPOLATION SCHEME; EXPENDABLE BATHYTHERMOGRAPH DATA; NATIONAL-METEOROLOGICAL-CENTER; GEOSAT ALTIMETER OBSERVATIONS; MESOSCALE CONVECTIVE SYSTEMS AB A major accomplishment of the recently completed Tropical Ocean-Global Atmosphere (TOGA) Program was the development of an ocean observing system to support seasonal-to-interannual climate studies. This paper reviews the scientific motivations for the development of that observing system, the technological advances that made it possible, and the scientific advances that resulted from. the availability of a significantly expanded observational database. A primary phenomenological focus of TOGA was interannual variability of the coupled ocean-atmosphere system associated with El Nino and the Southern Oscillation (ENSO). Prior to the start of TOGA, our understanding of the physical processes responsible for the ENSO cycle was limited, our ability to monitor variability in the tropical oceans was primitive, and the capability to predict ENSO was nonexistent. TOGA therefore initiated and/or supported efforts to provide real-time measurements of the following key oceanographic variables: surface winds, sea surface temperature, subsurface temperature, sea level and ocean velocity. Specific in situ observational; programs developed to provide these data sets included the Tropical Atmosphere-Ocean (TAO) array of moored buoys, in the Pacific, a surface drifting buoy program, an island and coastal tide gauge network, and a volunteer observing ship network of expendable bathythermograph measurements. Complementing these in situ efforts were satellite missions which provided near-global coverage of surface winds, sea surface temperature, and sea level. These new TOGA data sets led to fundamental progress in our understanding of the physical processes responsible for ENSO and to the development of coupled ocean-atmosphere models for ENSO prediction. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Natl Ocean Serv, Silver Spring, MD 20910 USA. Inst Francais Rech Sci Dev Cooperat, F-29263 Plouzane, France. NOAA, Aeron Lab, Boulder, CO 80303 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Natl Ctr Environm Predict, Camp Springs, MD 20746 USA. CSIRO, Div Oceanog, Hobart, Tas 7005, Australia. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Bur Meteorol, Res Ctr, Melbourne, Vic 3001, Australia. Hokkaido Univ, Inst Low Temp Sci, Sapporo, Hokkaido 060, Japan. RP McPhaden, MJ (reprint author), NOAA, Pacific Marine Environm Lab, Bldg 3,7600 Sand Point Way NE, Seattle, WA 98115 USA. EM mcphaden@pmel.noaa.gov RI surname, name/A-2183-2010; McPhaden, Michael/D-9799-2016 NR 535 TC 516 Z9 538 U1 4 U2 58 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14169 EP 14240 DI 10.1029/97JC02906 PG 72 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900002 ER PT J AU Wallace, JM Rasmusson, EM Mitchell, TP Kousky, VE Sarachik, ES von Storch, H AF Wallace, JM Rasmusson, EM Mitchell, TP Kousky, VE Sarachik, ES von Storch, H TI The structure and evolution of ENSO-related climate variability in the tropical Pacific: Lessons from TOGA SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-SURFACE TEMPERATURE; NINO SOUTHERN OSCILLATION; EASTERN EQUATORIAL ATLANTIC; EXTRATROPICAL SST ANOMALIES; EL-NINO; INTERANNUAL VARIABILITY; NORTHEAST BRAZIL; METEOROLOGICAL ASPECTS; GLOBAL TEMPERATURE; SAHEL RAINFALL AB Improved observations in the tropical Pacific during the Tropical Ocean-Global Atmosphere (TOGA) program have served to corroborate preexisting notions concerning the seasonally dependent relationships between sea surface temperature, sea level pressure, wind stress, rainfall, upper tropospheric circulation, and ocean thermal structure anomalies in the El Nino-Southern Oscillation (ENSO) phenomenon. However, the paradigm of a quasiperiodic "ENSO cycle," phase locked with the annual march, does not capture the complexity of the evolution of the anomalies. The inadequacy of this model was particularly apparent during the second half of TOGA when the variability was highly aperiodic. Also, a single modal structure or empirical orthogonal function does not appear to be capable of representing the range of spatial patterns of ocean-atmosphere interaction in the tropical Pacific. These results suggest the need for a more inclusive phenomenological description of ENSO. Data collected during TOGA serve to confirm the influence of tropical Atlantic sea surface temperature anomalies upon rainfall in northeast Brazil. C1 Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NOAA, NCEP, Climate Predict Ctr, Washington, DC 20233 USA. GKSS Forschungszentrum Geesthacht GmbH, Inst Hydrophys, D-21502 Geesthacht, Germany. RP Wallace, JM (reprint author), Univ Washington, Joint Inst Study Atmosphere & Ocean, Box 354235, Seattle, WA 98195 USA. RI von Storch, Hans/J-4165-2012 OI von Storch, Hans/0000-0002-5825-8069 NR 119 TC 255 Z9 272 U1 1 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14241 EP 14259 DI 10.1029/97JC02905 PG 19 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900003 ER PT J AU Trenberth, KE Branstator, GW Karoly, D Kumar, A Lau, NC Ropelewski, C AF Trenberth, KE Branstator, GW Karoly, D Kumar, A Lau, NC Ropelewski, C TI Progress during TOGA in understanding and modeling global teleconnections associated with tropical sea surface temperatures SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GENERAL-CIRCULATION MODEL; EXTRATROPICAL SST ANOMALIES; ROSSBY-WAVE PROPAGATION; SOUTHERN-HEMISPHERE CIRCULATION; LOW-FREQUENCY VARIABILITY; NORTH PACIFIC-OCEAN; 500-MB HEIGHT FLUCTUATIONS; MIDLATITUDE STORM TRACKS; STEADY LINEAR-RESPONSE; VARYING BASIC STATE AB The primary focus of this review is tropical-extratropical interactions and especially the issues involved in determining the response of the extratropical atmosphere to tropical forcing associated with sea surface temperature (SST) anomalies. The review encompasses observations, empirical studies, theory and modeling of the extratropical teleconnections with a focus on developments over the Tropical Oceans-Global Atmosphere (TOGA) decade and the current state of understanding. In the tropical atmosphere, anomalous SSTs force anomalies in convection and large-scale overturning with subsidence in the descending branch of the local Hadley circulation. The resulting strong upper tropospheric divergence in the tropics and convergence in the subtropics act as a Rossby wave source. The climatological stationary planetary waves and associated jet streams, especially in the northern hemisphere, can make the total Rossby wave sources somewhat insensitive to the position of the tropical heating that induces them and thus can create preferred teleconnection response patterns, such as the Pacific-North American (PNA) pattern. However, a number of factors influence the dispersion and propagation of Rossby waves through the atmosphere, including zonal asymmetries in the climatological state, transients, and baroclinic and nonlinear effects. Internal midlatitude sources can amplify perturbations. Observations, modeling, and theory have clearly shown how storm tracks change in response to changes in quasi-stationary waves and how these changes generally feedback to.maintain or strengthen the dominant perturbations through vorticity and momentum transports. The response of the extratropical atmosphere naturally induces changes in the underlying surface, so that there are changes in extratropical SSTs and changes in land surface hydrology and moisture availability that can feedback and influence the total response. Land surface processes are believed to be especially important in spring and summer. Anomalous SSTs and tropical forcing have tended to be strongest in the northern winter, and teleconnections in the southern hemisphere are weaker and more variable and thus more inclined to be masked by natural variability. Occasional strong forcing in seasons other than winter can produce strong and identifiable signals in the northern hemisphere and, because the noise of natural variability is less, the signal-to-noise ratio can be Large. The relative importance of tropical versus extratropical SST forcings has been established through numerical experiments with atmospheric general circulation models (AGCMs). Predictability of anomalous circulation and associated surface temperature and precipitation in the extratropics is somewhat limited by the difficulty of finding a modest signal embedded in the high level of noise from natural variability in the extra;tropics, and the complexity and variety of the possible feedbacks. Accordingly, ensembles of AGCM runs and time averaging are needed to identify signals and make predictions. Strong anomalous tropical forcing provides opportunities for skillful forecasts, and the accuracy and usefulness of forecasts is expected to improve as the ability to forecast the anomalous SSTs improves, as models improve, and as the information available from the mean and the spread of ensemble forecasts is better utilized. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Monash Univ, CRC So Hemisphere Meteorol, Clayton, Vic 3168, Australia. Natl Ctr Environm Predict, Washington, DC USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM trenbert@ncar.ucar.edu RI Karoly, David/C-8262-2011; Trenberth, Kevin/A-5683-2012 OI Karoly, David/0000-0002-8671-2994; Trenberth, Kevin/0000-0002-1445-1000 NR 178 TC 711 Z9 734 U1 8 U2 65 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14291 EP 14324 DI 10.1029/97JC01444 PG 34 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900005 ER PT J AU Stockdale, TN Busalacchi, AJ Harrison, DE Seager, R AF Stockdale, TN Busalacchi, AJ Harrison, DE Seager, R TI Ocean modeling for ENSO SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TROPICAL PACIFIC-OCEAN; GENERAL-CIRCULATION MODEL; SEA-SURFACE TEMPERATURE; NINO-SOUTHERN-OSCILLATION; NATIONAL-METEOROLOGICAL-CENTER; EQUATORIAL ATLANTIC-OCEAN; PRIMITIVE EQUATION MODEL; 1982-1983 EL-NINO; MERIDIONAL HEAT-TRANSPORT; SHALLOW-WATER SIMULATIONS AB Tropical ocean modeling has played a major part in the development of our knowledge of El Nino-Southern Oscillation (ENSO) during the Tropical Ocean-Global Atmosphere (TOGA) decade. Although the foundations had already been laid, it was only with the impetus from TOGA that tropical ocean modeling was able to develop so extensively. In this paper we discuss the development of the wide range of tropical ocean models in use today,from the simple to the complex; the ways in which their abilities to reproduce different phenomena have been assessed; and the ways in which they are being used to better understand and predict the behavior of the coupled ocean-atmosphere system in the tropics. Ocean model development is far from finished, however. Outstanding issues such as forcing fields, model improvements, testing strategies, and applications are also discussed. There is at least as much work to be done in the next decade as was achieved in the last. C1 European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RP Stockdale, TN (reprint author), European Ctr Medium Range Weather Forecasts, Shinfield Pk, Reading RG2 9AX, Berks, England. RI Harrison, Don/D-9582-2013 NR 294 TC 47 Z9 51 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14325 EP 14355 DI 10.1029/97JC02440 PG 31 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900006 ER PT J AU Delecluse, P Davey, MK Kitamura, Y Philander, SGH Suarez, M Bengtsson, L AF Delecluse, P Davey, MK Kitamura, Y Philander, SGH Suarez, M Bengtsson, L TI Coupled general circulation modeling of the tropical Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID OCEAN-ATMOSPHERE INTERACTION; NINO-SOUTHERN OSCILLATION; SEA-SURFACE TEMPERATURE; EL-NINO; INTERANNUAL VARIABILITY; GLOBAL OCEAN; SEASONAL CYCLE; CLIMATE MODEL; UNIFIED VIEW; MONSOON REGIONS AB During the Tropical Ocean-Global Atmosphere (TOGA) program substantial progress was made in the development of coupled general circulation models with regard to representation of the tropical mean state and climate variability. This paper provides a review of the main developments, focusing on the tropical Pacific region. Early coupled general circulation models were relatively crude; with coarse resolution and limited physical parameterizations and poor surface fluxes, the model drift from the observed mean state was often substantial, and their use for investigating climate variability such as El Nino-Southern Oscillation (ENSO) was limited. Improvements in resolution and parameterizations led to rapid progress. Through the TOGA program it has been possible to assess coupled model mean states and variability against high-quality observations, particularly for the tropical Pacific. Both components of the coupled system (ocean and atmosphere) have benefited from an improved understanding of the physics. Coupled experiments have revealed deficiencies in each model component that were concealed in separate forced runs. Several general systematic errors have yet to be eliminated, especially in the east Pacific. The variety of behavior obtained with coupled models provides evidence that more than one mechanism is active in the generation and evolution of ENSO events. There are also indications that interannual variability is linked to the mean structure of the equatorial Pacific. C1 Univ Pierre & Marie Curie, Lab Oceanog Dynam & Cimatol, Unite Mixte Rech CNRS ORSTOM UPMC, F-75005 Paris, France. Meteorol Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. RP Delecluse, P (reprint author), Univ Pierre & Marie Curie, Lab Oceanog Dynam & Cimatol, Unite Mixte Rech CNRS ORSTOM UPMC, Case 100,4 Pl Jussieu, F-75005 Paris, France. NR 124 TC 66 Z9 71 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14357 EP 14373 DI 10.1029/97JC02546 PG 17 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900007 ER PT J AU Latif, M Anderson, D Barnett, T Cane, M Kleeman, R Leetmaa, A O'Brien, J Rosati, A Schneider, E AF Latif, M Anderson, D Barnett, T Cane, M Kleeman, R Leetmaa, A O'Brien, J Rosati, A Schneider, E TI A review of the predictability and prediction of ENSO SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; NINO-SOUTHERN OSCILLATION; SEA-SURFACE TEMPERATURE; NATIONAL-METEOROLOGICAL-CENTER; CANONICAL CORRELATION-ANALYSIS; DATA ASSIMILATION SYSTEM; EL-NINO; TROPICAL PACIFIC; INTERANNUAL VARIABILITY; SEASONAL DEPENDENCE AB A hierarchy of Fl Nino-Southern Oscillation (ENSO) prediction schemes has been developed during the Tropical Ocean-Global Atmosphere (TOGA) program which includes statistical schemes and physical models.The statistical models are, in general, based on linear statistical techniques and can be classified into models which use atmospheric (sea level pressure or surface wind) or oceanic (sea surface temperature or a measure of upper ocean heat content) quantities or a combination of oceanic and atmospheric quantities as predictors. The physical models consist of coupled ocean-atmosphere models of varying degrees of complexity, ranging from simplified coupled models of the "shallow water" type to coupled general circulation models. All models, statistical and physical, perform considerably better than the persistence forecast in predicting typical indices of ENSO on lead times of 6 to 12 months. The TOGA program can be regarded as a success from this perspective. However, despite the demonstrated predictability, little is known about ENSO predictability limits and the predictability of phenomena outside the tropical Pacific. Furthermore, the predictability of anomalous features known to be associated with ENSO (e.g., Indian monsoon and Sahel rainfall, southern African drought, and off-equatorial sea surface temperature) needs to be addressed in more detail. As well, the relative importance of different physical mechanisms (in the ocean or atmosphere) has yet to be established. A seasonal dependence in predictability is seen in many models, but the processes responsible for it are not fully understood, and its meaning is still a matter of scientific discussion. Likewise, a marked decadal variation in skill is observed, and the reasons for this are still under investigation. Finally, the different prediction models yield similar skills, although they are initialized quite differently. The reasons for these differences are also unclear. C1 Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Clarendon Lab, Dept Atmospher Phys, Oxford OX20 1JE, England. Univ Calif San Diego, Scripps Inst Oceanog, Div Climate Res, La Jolla, CA 92093 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10960 USA. Bur Meteorol, Res Ctr, Melbourne, Vic 3001, Australia. Natl Meteorol Ctr, Coupled Model Project, Camp Springs, MD 20746 USA. Florida State Univ, Ctr Ocean Atmosphere Predict Studies, Tallahassee, FL 32306 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Ctr Ocean Land Atmosphere Studies, Calverton, MD 20705 USA. RP Max Planck Inst Meteorol, Bundesstr 55, D-20146 Hamburg, Germany. EM latif@dkrz.de RI Latif, Mojib/C-2428-2016 OI Latif, Mojib/0000-0003-1079-5604 NR 112 TC 273 Z9 292 U1 2 U2 42 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 29 PY 1998 VL 103 IS C7 BP 14375 EP 14393 DI 10.1029/97JC03413 PG 19 WC Oceanography SC Oceanography GA ZX085 UT WOS:000074477900008 ER PT J AU Angevine, WM Grimsdell, AW McKeen, SA Warnock, JM AF Angevine, WM Grimsdell, AW McKeen, SA Warnock, JM TI Entrainment results from the Flatland boundary layer experiments SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WIND PROFILER; SOLAR-RADIATION; BUDGET ANALYSIS; SURFACE HEAT; AEROSOLS; TEMPERATURE; MOISTURE; PRAIRIE; CLIMATE; ERRORS AB A primary objective of the 1995 and 1996 Flatland boundary layer experiments, known as Flatland95 and Flatland96, was to measure and characterize entrainment at the top of the convective boundary layer. The experiments took place in the area near the Flatland Atmospheric Observatory near Champaign-Urbana, Illinois, in August-September 1995 and June-August 1996. The site is interesting because it is extraordinarily flat, has uniform land use, and is situated in a prime agricultural area. Measurements in the entrainment zone are difficult to make due to the time and space scales involved. We will present entrainment estimates derived from budget calculations with data from UHF wind profiling radars and from radiosondes. The results demonstrate that the remote sensing instruments produce results comparable to radiosondes and have significant advantages for boundary layer studies. Surface flux measurements are also used in the calculations. Direct heating by shortwave radiation absorbed by aerosols in the boundary layer is found to be an important component of the boundary layer heat budgets. The entrainment virtual temperature flux and the ratio of entrainment to surface flux found from the budget calculations are somewhat larger than expected. Advection of warm air, which is not accounted for in the budget calculations, is probably a factor in some periods but may not be significant in the full data set. For the full data set, the mean entrainment velocity found from the heat budget is 0.03 +/- 0.01 m s(-1), slightly less than the mean rate of change of the boundary layer height. The mean entrainment ratio A(R) is 0.51 +/- 0.12 and the median is 0.43, comparable to results from some other studies in comparable conditions. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Angevine, WM (reprint author), NOAA, Aeron Lab, 325 Broadway R-E-AL3, Boulder, CO 80303 USA. EM wayne@al.noaa.gov; agrimsdell@al.noaa.gov; stu@al.noaa.gov RI Angevine, Wayne/H-9849-2013; McKeen, Stuart/H-9516-2013 OI Angevine, Wayne/0000-0002-8021-7116; NR 39 TC 28 Z9 31 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 13689 EP 13701 DI 10.1029/98JD01150 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500001 ER PT J AU Kayano, MT Kousky, VE AF Kayano, MT Kousky, VE TI Zonally symmetric and asymmetric features of the tropospheric Madden-Julian oscillation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC ANGULAR-MOMENTUM; OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; NORTHERN HEMISPHERE SUMMER; INTRASEASONAL OSCILLATIONS; CIRCULATION ANOMALIES; TROPICAL CONVECTION; SEASONAL-VARIATIONS; GLOBAL ATMOSPHERE; LENGTH AB The evolving intraseasonal (IS) modes of the zonally symmetric (ZS) part (the latitudinal profile) of the 200-hPa stream function have been determined by performing extended empirical orthogonal function (EEOF) analyses for the northern hemisphere (NH) summer and winter. In each analysis the first EEOF mode describes an oscillation with a period of about 50 days. The prominent feature of the upper tropospheric stream function latitudinal profiles, for both seasons, is the propagation of the largest loadings in both hemispheres from near the equator toward higher latitudes. This propagation is more evident during the NH winter and throughout the year in the southern hemisphere (SH). In the NH the poleward propagation of the loadings is more conspicuous within the equator and the 30 degrees N latitudinal band. The associated patterns for the zonally asymmetric (ZA) part of the sea level pressure and the 850- and 200-hPa zonal winds have also been determined. These patterns feature, in general, the largest correlations in the tropics and a large-scale zonal wavenumber one structure propagating continuously eastward around the globe with a 50-day period. The ZA patterns for certain variables show strong seasonal dependence. The 850-hPa ZA zonal wind patterns feature the largest correlations approximately along the climatological position of the Intertropical Convergence Zone, whereas the largest correlations for the upper level ZA zonal wind patterns are found near the equator, mainly in the winter hemisphere. C1 Inst Nacl Pesquisas Espaciais, BR-12201970 Sao Jose Dos Campos, Brazil. Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Kayano, MT (reprint author), Inst Nacl Pesquisas Espaciais, CP 515, BR-12201970 Sao Jose Dos Campos, Brazil. EM mary@met.inpe.br; wd52vk@hp31.wwb.noaa.gov NR 32 TC 4 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 13703 EP 13712 DI 10.1029/98JD01145 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500002 ER PT J AU Congeduti, F DeLuisi, J DeFoor, T Thomason, L AF Congeduti, F DeLuisi, J DeFoor, T Thomason, L TI Optical extinction properties of volcanic stratospheric aerosol derived from ground-based lidar and Sun photometer measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHICHON ERUPTION CLOUD; EL-CHICHON; CORRELATIVE MEASUREMENTS; SIZE DISTRIBUTIONS; MOUNT-PINATUBO; OCTOBER 1982; MAUNA-LOA; BACKSCATTER; MODEL; MASS AB Measurements of lidar-integrated backscatter and Sun photometer optical thickness made at Mauna Loa, Hawaii (19.5 degrees N), were used to compute the bulk columnar value of the extinction-to-backscatter ratio S-c of stratospheric aerosol during a period of major stratospheric aerosol contamination following the eruption of El Chichon (Mexico, 17.3 degrees N, March-April 1982). Values of S-c were also calculated using observations of integrated backscatter and aerosol optical thickness collected from various sources in the northern midlatitude region. The calculated values of S-c were found to range between 40 and 70 sr at a wavelength of 0.694 mu m during periods when high and moderate stratospheric aerosol concentrations were observed. Variations of S-c with time of approximately 20-30% are noted in the results. Similar S-c results obtained by other investigators are compared with the results of this investigation. Overall, the agreement among the various results was found to be consistent within their uncertainties. Values of S-c were also calculated for the stratospheric aerosol from the eruption of Mount Pinatubo (Philippines, 15 degrees N, June 1991). The Mount Pinatubo results were about 15% lower than the El Chichon results during their early stages. Differences between the El Chichon and the Pinatubo results are within their error bounds. C1 CNR, Ist Fis Atmosfera, I-00044 Frascati, Italy. NOAA, Environm Res Labs, Boulder, CO 80303 USA. NASA, Langley Atmospher Res Ctr, Hampton, VA 23681 USA. RP Congeduti, F (reprint author), CNR, Ist Fis Atmosfera, CP 27, I-00044 Frascati, Italy. EM deluisi@srrb.noaa.gov OI Thomason, Larry/0000-0002-1902-0840 NR 41 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 13893 EP 13902 DI 10.1029/98JD00942 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500015 ER PT J AU MacGorman, DR Morgenstern, CD AF MacGorman, DR Morgenstern, CD TI Some characteristics of cloud-to-ground lightning in mesoscale convective systems SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT 10th International Conference on Atmospheric Electricity (ICAE 10) CY JUN 10-13, 1996 CL OSAKA, JAPAN SP Int Commiss Atmospher Electr, Meterol Soc Japan, Int Union Radio Sci, Inst Electr Engn Japan, Japan Res Grp Electr Discharge, Sci Council Japan, Commemorat Assoc Japan World Expoosit ID FLASH CHARACTERISTICS; DIRECTION-FINDER; STROKES; NETWORK; STORM; THUNDERSTORMS; CALIBRATION; LOCATIONS AB Selected characteristics of cloud-to-ground lightning were analyzed for twenty-five mesoscale convective systems (MCSs) that occurred within the range of the National Severe Storm Laboratory direction-finder network during the warm season of 1986. Positive ground flashes comprised 6% of ground flashes in MCSs versus 4% in warm-season thunderstorms overall. For negative ground flashes the distribution of estimated peak currents from MCSs appeared almost identical to the distribution from all thunderstorms. The distribution of estimated peak currents varied more fi:om MCS to MCS for positive ground flashes than for negative ground flashes, and the distributions for positive ground flashes in MCSs usually appeared much different from those for storms overall. We divided the spectrum of peak current distributions for positive ground flashes of individual MCSs into three categories: (I.) the small-amplitude category (mode of 9-13 kA; few flashes with >40 kA), (2) the middle-amplitude category (mode of 13-17 kA; many flashes with >40 kA), and (3) the large-amplitude category (mode of 51-56 kA). MCSs in the large-amplitude category occurred throughout the warm season; those in the small-amplitude category, primarily during April, May, and September; and those in the middle-amplitude category, during June-August. The maximum total ground flash rate per 30-min period in each MCS tended to be smallest in the large-amplitude category. Median peak currents for all 30-min periods of MCSs in our analysis converged on a relatively narrow range of values when flash rates of a given ground flash polarity increased to large values. For negative ground flashes the median peak currents converged on 25-30 kA in all MCSs. For positive ground flashes the median peak currents converged on one of two narrow ranges: roughly 10 kA for the small-amplitude category and 60 kA for the large- and middle-amplitude categories. C1 NOAA, Environm Res Lab, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. USAF, Norman, OK USA. RP MacGorman, DR (reprint author), NOAA, Environm Res Lab, Natl Severe Storms Lab, 1313 Halley Cir, Norman, OK 73069 USA. EM don.macgorman@nssl.noaa.gov; MORGECD@alfa.com OI MacGorman, Donald/0000-0002-2395-8196 NR 31 TC 29 Z9 32 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 14011 EP 14023 DI 10.1029/97JD03221 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500029 ER PT J AU Stolzenburg, M Rust, WD Smull, BF Marshall, TC AF Stolzenburg, M Rust, WD Smull, BF Marshall, TC TI Electrical structure in thunderstorm convective regions - 1. Mesoscale convective systems SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT 10th International Conference on Atmospheric Electricity (ICAE 10) CY JUN 10-13, 1996 CL OSAKA, JAPAN SP Int Commiss Atmospher Electr, Meterol Soc Japan, Int Union Radio Sci, Inst Electr Engn Japan, Japan Res Grp Electr Discharge, Sci Council Japan, Commemorat Assoc Japan World Expoosit ID MIDLATITUDE SQUALL LINE; DOPPLER RADAR; KINEMATIC STRUCTURE; STRATIFORM REGION; TRAILING REGION; PRECIPITATION; FIELD; OKLAHOMA; DOWNDRAFTS; CHARGE AB Electric field (E) soundings through convective regions of mesoscale convective systems (MCSs) sire examined in this paper. Ten E soundings through updrafts in MCS convective regions and five soundings in MCS convective regions outside updrafts are used to show that a typical electrical structure exists in this region. These 15 E soundings plus one other previously published sounding, which is included in this analysis, comprise all known soundings in the convective region of MCSs. The basic charge structure identified in MCS updrafts consists of four charge regions, alternating in polarity, with the lowest region positive and the highest region negative. The basic charge structure outside updrafts in MCS convective regions has six charge regions, alternating in polarity, with a positive charge region lowest. Maximum E magnitudes of both polarities are larger and are located at lower heights in soundings outside updrafts compared to those within updrafts. Excepting the upper positive charge, inferred charge regions are shallower and have larger charge densities outside updrafts. The center of the main negative charge is lower and warmer outside updrafts (5.5 km, -6.2 degrees C) than within updrafts (6.9 km, -15.7 degrees C). These features inside and outside updrafts are incorporated in a new conceptual model of MCS convective region charge structure. Also, an expanded conceptual model is developed, using previously published data from other parts of MCSs. This more complete conceptual model shows the typical electrical charge, airflow, and reflectivity features in the stratiform region, the transition zone:, and the convective region of midlatitude mesoscale convective systems. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. RP Stolzenburg, M (reprint author), Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. EM mstolzen@beautyl.phy.olemiss.edu; drust@nsslgate.nssl.noaa.gov; smull@atmos.washington.edu; marshall@beautyl.phy.olemiss.edu OI Stolzenburg, Maribeth/0000-0001-8773-8101 NR 46 TC 81 Z9 93 U1 2 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 14059 EP 14078 DI 10.1029/97JD03546 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500032 ER PT J AU Stolzenburg, M Rust, WD Marshall, TC AF Stolzenburg, M Rust, WD Marshall, TC TI Electrical structure in thunderstorm convective regions - 2. Isolated storms SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT 10th International Conference on Atmospheric Electricity (ICAE 10) CY JUN 10-13, 1996 CL OSAKA, JAPAN SP Int Commiss Atmospher Electr, Meterol Soc Japan, Int Union Radio Sci, Inst Electr Engn Japan, Japan Res Grp Electr Discharge, Sci Council Japan, Commemorat Assoc Japan World Expoosit ID NEW-MEXICO THUNDERSTORM; CHARGED PRECIPITATION MEASUREMENTS; LIGHTNING FLASH; TORNADIC STORM; FIELD; THUNDERCLOUD; DISTRIBUTIONS; OKLAHOMA; SYSTEMS; ICE AB Electric field (E) soundings through the convective regions of two types of isolated thunderstorms are examined. Analysis of seven soundings through strong updrafts of isolated supercell storms show that the basic E structure there has three \El peaks: a positive peak near 8 km height, a negative peak near 10.5 km, and a positive peak near 12 km. Strong updraft soundings are those with average balloon ascent rates in excess of 10 m s(-1). The basic charge structure in strong updrafts of supercells has four charge regions of alternating polarity. The lowermost charge is positive, between about 4 and 8 km, and the uppermost region is negative. Ail the supercell updraft soundings are incomplete due to balloon burst or lightning-induced instrument destruction below cloud top. Six supercell soundings that ascended outside strong updrafts are used to show that the E and charge structures there are more complex than within the strong updrafts. Analysis of 15 new or previously published soundings through small, New Mexican mount;lin thunderstorms indicates that the basic E structure in or near their convective cores consists of three \El peaks: a lower positive peak at about 5 km height, a midlevel negative peak near 6.5 km, and an upper positive peak near 9.5 km. The basic charge structure near the center of New Mexican storm convection has four charge regions, alternating in polarity, with a positive charge region lowest. Soundings in New Mexican convection that did not ascend near the convective cores show more complex E profiles and charge structures. C1 Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Stolzenburg, M (reprint author), Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. EM mstolzen@beautyl.phy.olemiss.edu; drust@nsslgate.nssl.noaa.gov; marshall@beautyl.phy.olemiss.edu OI Stolzenburg, Maribeth/0000-0001-8773-8101 NR 40 TC 67 Z9 78 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 14079 EP 14096 DI 10.1029/97JD03547 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500033 ER PT J AU Stolzenburg, M Rust, WD Marshall, TC AF Stolzenburg, M Rust, WD Marshall, TC TI Electrical structure in thunderstorm convective regions - 3. Synthesis SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT 10th International Conference on Atmospheric Electricity (ICAE 10) CY JUN 10-13, 1996 CL OSAKA, JAPAN SP Int Commiss Atmospher Electr, Meterol Soc Japan, Int Union Radio Sci, Inst Electr Engn Japan, Japan Res Grp Electr Discharge, Sci Council Japan, Commemorat Assoc Japan World Expoosit ID FIELD MEASUREMENTS; SCREENING LAYERS; TORNADIC STORM; SPACE-CHARGE; CLOUDS; PRECIPITATION; THUNDERCLOUD; ELECTRIFICATION; CORONAE; ANVIL AB In this paper, results from nearly 50 electric field soundings through convective regions of mesoscale convective systems (MCSs), isolated supercells, and isolated New Mexican mountain storms are compared and synthesized. These three types of thunderstorm convection are found to have a common, basic electrical structure. Within convective updrafts the basic charge structure has four charge regions, alternating in polarity, and the lowest is positive. Outside updrafts of convection there are typically at least six charge regions, alternating in polarity, and th: lowest is again positive. Among the three storm types, there are differences in the heights and temperatures at which the basic four charge regions are found in updrafts. The height (temperature) of the center of the main negative charge region averages 6.93 km (-16 degrees C) in MCS convective region updrafts, 9.12 km (-22 degrees C) in supercell updrafts, and 6.05 km (-7 degrees C) in New Mexican mountain storm updrafts. In updraft soundings through all three storm types, the center height of the main negative charge region increases with increasing average balloon ascent rate and updraft speed at a rate of about 0.3 km per 1 m s(-1), with a correlation coefficient of 0.94. A schematic illustrates the basic four- and six-charge structure for thunderstorm convective regions, and it is offered as an improved model for thunderstorm charge structure. C1 Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Stolzenburg, M (reprint author), Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. EM mstolzen@beautyl.phy.olemiss.edu; drust@nsslgate.nssl.noaa.gov; marshall@beautyl.phy.olemiss.edu OI Stolzenburg, Maribeth/0000-0001-8773-8101 NR 51 TC 110 Z9 126 U1 3 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1998 VL 103 IS D12 BP 14097 EP 14108 DI 10.1029/97JD03545 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZW708 UT WOS:000074439500034 ER PT J AU Siegrist, T Vanderahb, TA Ramirez, AP Geyer, RG Roth, RS AF Siegrist, T Vanderahb, TA Ramirez, AP Geyer, RG Roth, RS TI Crystal structure and properties of Ba5Fe4Ti10O31 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE Ba5Fe4Ti10O31; barium iron titanium oxide; crystal structure; X-ray diffraction; magnetic susceptibility; dielectric constant; dielectric loss tangent ID DIFFRACTION; CHEMISTRY; SOLIDS; OXIDES AB Using single-crystal and powder X-ray diffraction methods, the crystal structure of Ba5Fe4Ti10O31 was determined and its magnetic and dielectric properties were measured. Ba5Fe4Ti10O31 crystallizes in space group P6(3)/mcm (No. 193) (a=9.9886(2), c=42.226(2) Angstrom: Z=6: rho(calc)=5.15 g cm(-3)) and exhibits an 18-layer close-packed structure built from vacancy-free [O,(Ba,O)] layers. The structure features octahedral sites occupied by a mixture of Fe3+ and Ti4+, with some preferential ordering, and tetrahedral sites occupied by Fe3+ one of which shares faces and is half occupied. Some Ba ions in :he structure display (9+3) coordination with three unusually long Ba-O bond distances. Computation of bond valence sums about the cation sites using the observed bond distances reveals significant deviations from the valence sum rule, indicating that the structure of Ba5Fe4Ti10O31 contains residual strain not relieved by distortion. Indexed experimental X-ray powder diffraction data for Ba5Fe4Ti10O31 are given and are in excellent agreement with those calculated from the results of the single-crystal structure determination. The compound exhibits approximately paramagnetic behavior that deviates somewhat from the Curie Law. Application of this formalism to the 1/chi vs. T data above 250 K yields an effective moment consistent with the presence of high-spin Fe3+ (S=5/2), and a negative Weiss constant (approximate to-190 K) indicating cooperative magnetic interactions that are overall antiferromagnetic. The relative permittivity and dielectric loss tangent of a sintered polycrystalline disk of Ba5Fe4Ti10O31 were measured between 7.1 and 7.7 GHz, yielding values (corrected for theoretical density) of 32 and 3.3(+/-0.3)x10(-3), respectively, that were essentially independent of frequency. (C) 1998 Elsevier Science S.A. C1 AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. NIST, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Siegrist, T (reprint author), AT&T Bell Labs, Lucent Technol, 600 Mt Ave, Murray Hill, NJ 07974 USA. NR 20 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD JUN 26 PY 1998 VL 274 IS 1-2 BP 169 EP 178 DI 10.1016/S0925-8388(98)00534-9 PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 105DT UT WOS:000075058000029 ER PT J AU Wladkowski, BD Chenoweth, SA Jones, KE Brown, JW AF Wladkowski, BD Chenoweth, SA Jones, KE Brown, JW TI Exocyclic hydroxymethyl rotational conformers of beta- and alpha-D-glucopyranose in the gas phase and aqueous solution SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; FORCE-FIELD; AB-INITIO; CONFORMATIONAL-ANALYSIS; ANOMERIC EQUILIBRIUM; D-GLUCOSE; STEREOCHEMICAL ASPECTS; ORBITAL CALCULATIONS; STRUCTURAL MOIETIES; FREE-ENERGY AB The intrinsic exocyclic hydroxymethyl rotational surface for beta-D-glucoppranose as well as the beta-alpha anomer energy difference for D-glucopyranose has been studied using ab initio quantum mechanical methods including continuum solvation, Relevant stationary points, including rotational transition states, have been characterized by full geometry optimization using the 6-31G(d) basis set for the most stable counterclockwise (cc) overall conformation. Effects of dynamic electron correlation on both the geometric structures and the relative energetics of this system are also explored using Moller-Plesset perturbation theory (MP2 through MP4-(SDTQ)) and density functional methods (BLYP). A total of six stationary points, including three minima and three transition states, were identified along the exocyclic rotational surface. All three minima were found to be very close in energy with a final order of GG (0.0) < CT (2.84) < TG (3.05) based on the relative free energy, Delta G(298)degrees determined at the MP4(SDTQ)/6-31G(d)//MP2/6-31G(d) level of theory. The rotational transition state free energy differences varied from 18.8 to 28.9 kJ mol-l at the same level of theory with the transition state connecting the TG and GG minima being the lowest. The intrinsic gas-phase beta-alpha anomer free energy difference for the cc-TG conformer of D-glucopyranose was also determined at various levels of theory. On the basis of the convergence of the MP series, this energetic quantity has been estimated at 8 +/- 2 kJ mol(-1) favoring the or-anomer, and is insensitive to exocyclic hydroxymethyl rotation. Two different solvation models were used to explore the effects of aqueous solvation on the energetic parameters mentioned above. The Onsager continuum solvation model and the self-consistent isodensity polarized continuum model (SCIPCM) showed significant, yet predictable, effects on the exocyclic hydroxymethyl rotational surface for beta-D-glucopyranose. Shifts in the relative energetics compared to those for the gas phase ranged from -0.8 to + 2.8 kJ mol(-1) for Onsager dipole model and -1.6 to as much as +4.7 kJ mol(-1) for the SCIPCM model at the MP2 6-31G(d) level, resulting in a qualitative change in the ordering of the relative stability of the three stable minima. The effects of the solvation models on the beta-alpha anomer energy difference were also significant, showing a relative decrease in the beta-alpha anomer energy difference from the intrinsic gas-phase result. However, it is clear that these specific continuum solvation models alone cannot account for the experimentally observed preference of the beta-anomer in aqueous solution. C1 Western Maryland Coll, Dept Chem, Westminster, MD 21157 USA. Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. RP Wladkowski, BD (reprint author), Western Maryland Coll, Dept Chem, 2 Coll Hill, Westminster, MD 21157 USA. NR 42 TC 30 Z9 30 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 25 PY 1998 VL 102 IS 26 BP 5086 EP 5092 DI 10.1021/jp980524+ PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZY136 UT WOS:000074589900017 ER PT J AU Luo, R Head, MS Moult, J Gilson, MK AF Luo, R Head, MS Moult, J Gilson, MK TI pK(a) shifts in small molecules and HIV protease: Electrostatics and conformation SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DIELECTRIC-PROPERTIES; FREE-ENERGIES; PROTEINS; DYNAMICS; SIMULATIONS; PREDICTION; SOLVATION; PROGRAM; MODELS AB The generalized Barn (GB) approximation is a reasonable electrostatic model that is fast enough for use with extensive conformational sampling. This study combines the GB model with a torsion-space sampling method to compute pK(a) shifts for a series of dicarboxylic acids and amino acids, and for the active-site aspartyl dyad in HIV-1 protease. The calculations agree rather well with experiment for the small molecules Conformational analysis shows salt-bridging for the zwitterionic amino acids but otherwise modest electrostatic effects upon mean chain lengths. The calculations also show that through-space electrical fields alone cannot account completely for the observed pK(a) shifts. The calculations for HIV protease agree reasonably well with experiment, despite the complexity of the system. The present computational approach should be useful for a variety of other applications. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gilson, MK (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI Luo, Ray/I-6928-2012 OI Luo, Ray/0000-0002-6346-8271 NR 54 TC 51 Z9 51 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 24 PY 1998 VL 120 IS 24 BP 6138 EP 6146 DI 10.1021/ja974307i PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ZW519 UT WOS:000074419100034 ER PT J AU Rye, BJ Hardesty, RM AF Rye, BJ Hardesty, RM TI Estimate optimization parameters for incoherent backscatter heterodyne lidar (vol 36, pg 9425, 1997) SO APPLIED OPTICS LA English DT Correction C1 Univ Colorado, Cooperat Inst Res Environm Sci, Environm Technol Lab, Boulder, CO 80303 USA. NOAA, Cooperat Inst Res Environm Sci, Environm Technol Lab, Boulder, CO 80303 USA. RP Rye, BJ (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. RI Hardesty, Robert/H-9844-2013 NR 1 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1998 VL 37 IS 18 BP 4016 EP 4016 DI 10.1364/AO.37.004016 PG 1 WC Optics SC Optics GA ZT886 UT WOS:000074127900027 PM 18273373 ER PT J AU Daniel, JS Solomon, S AF Daniel, JS Solomon, S TI On the climate forcing of carbon monoxide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID KINETIC DATA EVALUATION; ATMOSPHERIC CHEMISTRY; IUPAC SUBCOMMITTEE; PHOTOCHEMICAL DATA; METHANE; TROPOSPHERE; PHOTOLYSIS; LIFETIMES; INCREASE; GROWTH AB Carbon monoxide plays a primary role in governing OH abundances in the troposphere. It is likely that through this chemical interaction, CO plays an important role in climate forcing by affecting CH4 concentrations. We use a photochemical box model to estimate the indirect global warming potential (GWP) of tropospheric carbon monoxide resulting from its effect on methane abundances. We also consider indirect GWPs of CO due to carbon dioxide production and possible CO GWP ranges due to ozone production to estimate a total CO indirect GWP range over various time horizons. We estimate that for current emission levels, the short-term (<15 years) cumulative radiative forcing due to the direct anthropogenic emission of CO may be larger than the cumulative forcing due to anthropogenically emitted N2O. C1 NOAA, Aeron Lab, R E AL8, Boulder, CO 80303 USA. RP Daniel, JS (reprint author), NOAA, Aeron Lab, R E AL8, 325 Broadway, Boulder, CO 80303 USA. EM jdaniel@al.noaa.gov RI Daniel, John/D-9324-2011 NR 37 TC 106 Z9 117 U1 3 U2 22 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13249 EP 13260 DI 10.1029/98JD00822 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200013 ER PT J AU Penkett, SA Volz-Thomas, A Parrish, DD Honrath, RE Fehsenfeld, FC AF Penkett, SA Volz-Thomas, A Parrish, DD Honrath, RE Fehsenfeld, FC TI Special section: North Atlantic Regional Experiment (NARE II) - Preface SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material C1 Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. Forschungszentrum Julich, Inst Belasteten Atmosphare, Julich, Germany. NOAA, Aeron Lab, Environm Res Lab, Boulder, CO 80303 USA. Michigan Technol Univ, Dept Civil & Environm Engn, Houghton, MI 49931 USA. RP Penkett, SA (reprint author), Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. RI Parrish, David/E-8957-2010; Fehsenfeld, Frederick/I-4876-2013; Volz-Thomas, Andreas/J-7223-2012 OI Parrish, David/0000-0001-6312-2724; Volz-Thomas, Andreas/0000-0003-3700-1667 NR 6 TC 6 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13353 EP 13355 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200020 ER PT J AU Parrish, DD Trainer, M Holloway, JS Yee, JE Warshawsky, MS Fehsenfeld, FC Forbes, GL Moody, JL AF Parrish, DD Trainer, M Holloway, JS Yee, JE Warshawsky, MS Fehsenfeld, FC Forbes, GL Moody, JL TI Relationships between ozone and carbon monoxide at surface sites in the North Atlantic region SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERE; STRATOSPHERE; ATMOSPHERE; TRANSPORT; POLLUTION; BERMUDA; OCEAN AB As part of the North Atlantic Regional Experiment (NARE), measurements of O-3 and CO at five surface sites were made from July 1991 to January 1995. The investigation of the variabilities and correlation of O-3 and CO presented here indicates that the seasonal cycles of the medians and the means of O-3 and CO are qualitatively similar to the cycles observed at other northern midlatitude sites. The signature of O-3 produced from anthropogenic precursors is dearest in the spring at the Azores and in the summer at Sable Island. The influence of the natural stratospheric O-3 source is apparent at Sable Island, particularly in the spring. At ah sites the variability of CO throughout the year is dominated by episodes of pollution transport. The slopes of the monthly O-3-CO correlations in the summer in Atlantic Canada and the spring in the Azores are quite uniform at 0.3 to 0.4. However, individual pollution transport events often have larger (less than or equal to 1.0) slopes, which indicate significantly different net O-3 production efficiencies between episodes. The average slope of O-3 versus CO at Sable Island in the winter for moderate pollution transport events (CO less than or equal to 180 ppbv) is -0.28, which indicates that the titration of ambient O-3 by emitted NO with little if any photochemical O-3 production dominates the O-3 chemistry over eastern North America in winter. Diurnal cycles driven by photochemistry are observed in the summer for both O-3 and CO at the Azores (net loss) and Sable Island (net production.) These observations are consistent with the work of Duderstadt et al. [this issue] who find positive net photochemical O-3 production at Sable Island, and with the modeling of Atherton et al. [1996] who find a region dominated by photochemical loss of O-3 and CO in the central Atlantic. C1 NOAA, Boulder, CO 80303 USA. Atmospher Environm Serv Sable Isl, Bedford, NS B4A 1E5, Canada. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Parrish, DD (reprint author), NOAA, 325 Broadway,R-E-AL7, Boulder, CO 80303 USA. EM parrish@al.noaa.gov; gforbes@fox.nstn.ca; moody@virginia.edu RI Parrish, David/E-8957-2010; Holloway, John/F-9911-2012; Trainer, Michael/H-5168-2013; Fehsenfeld, Frederick/I-4876-2013 OI Parrish, David/0000-0001-6312-2724; Holloway, John/0000-0002-4585-9594; NR 34 TC 151 Z9 155 U1 2 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13357 EP 13376 DI 10.1029/98JD00376 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200021 ER PT J AU Knapp, KG Jensen, ML Balsley, BB Bognar, JA Oltmans, SJ Smith, TW Birks, JW AF Knapp, KG Jensen, ML Balsley, BB Bognar, JA Oltmans, SJ Smith, TW Birks, JW TI Vertical profiling using a complementary kite and tethered balloon platform at Ferryland Downs, Newfoundland, Canada: Observation of a dry, ozone-rich plume in the free troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BOUNDARY-LAYER AB Vertical profiles of ozone mixing ratio, water vapor mixing ratio, and temperature obtained during August 3-13, 1995, at Ferryland Downs, Newfoundland, Canada, as part of the North Atlantic Regional Experiment (NARE) demonstrate the use of high-altitude tethered balloons and kites as measurement platforms. In combination with a novel, fast winching system, previously developed for use with kites, tethered balloons were used for profiling chemical species and meteorological parameters to altitudes as high as 7.6 km. Tethered balloon profiling complements profiling with kite systems by expanding the range of wind conditions over which data can be obtained. A total of 65 profiles were collected using these platforms. Elevated ozone mixing ratios highly anticorrelated with water vapor mixing ratios observed during August 4-7 suggest all upper atmospheric source for ozone-rich air during summertime in the Maritime Provinces of Canada. Ozone mixing ratios reaching 100 parts per billion by volume (ppbv) in this air mass were associated with water vapor mixing ratios as low as 0.1 g kg(-1). Profiles collected during August 11-13 demonstrate the use of kite and balloon systems to obtain vertical profiles over a wide range of wind conditions. Ozone mixing ratios of 65 ppbv were observed at 1 km altitude on August 12, while profiles collected on August 13 exhibit no evidence of elevated ozone. These results document the rapid transport of an air mass containing elevated ozone levels over the sampling site that would not have been possible with either system alone. C1 Univ Colorado, CIRES, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Birks, JW (reprint author), Univ Colorado, CIRES, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. EM knappk@ucsu.colorado.edu; mike@machu.colorado.edu; balsley@terra.colorado.edu; soltmans@cmdl.noaa.gov; tsmith@kaitain.sp.trw.com; chemdir@colorado.edu RI Birks, John/H-7451-2013 OI Birks, John/0000-0003-1691-1354 NR 15 TC 12 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13389 EP 13397 DI 10.1029/97JD01831 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200023 ER PT J AU Peterson, MC Honrath, RE Parrish, DD Oltmans, SJ AF Peterson, MC Honrath, RE Parrish, DD Oltmans, SJ TI Measurements of nitrogen oxides and a simple model of NOy fate in the remote North Atlantic marine atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ASTEX LAGRANGIAN EXPERIMENTS; BOUNDARY-LAYER DYNAMICS; OZONE; TROPOSPHERE; NITRATE; FLOW; ENTRAINMENT; CLOUDINESS; AEROSOL AB NO and NOy (total reactive oxidized nitrogen) were measured at a site in the Azores (21.322 degrees W, 38.732 degrees N, 1 km altitude) over a 3 week period in August and September 1993, during the first summer intensive of the North Atlantic Regional Experiment (NARE). These measurements were performed to determine background reactive nitrogen oxides levels and to assess the impact that long-range transport of reactive nitrogen oxides associated with human activities have on these levels. Median NOy mixing ratios during background marine boundary layer (MBL) periods ranged from 59 to 93 parts per trillion by volume (pptv), with an overall median of 73 pptv. Analysis of back trajectories, low and uncorrelated CO and O-3 levels, and low levels of MBL NOy indicate that the central North Atlantic region was not influenced by direct transport of anthropogenic emissions during the period of this study. Changes in NOy levels during two MBL periods with adjacent in and out-of-cloud events indicated that up to 45-47% of MBL NOy was scavenged by clouds. However, mean NOy levels during all in-cloud periods (similar to 70 pptv) and all out-of-cloud periods (similar to 80 pptv) were not significantly different, apparently because of variability in MBL NOy levels. In addition to the MBL periods, there were two periods when the site was within the free troposphere (FT), as indicated by vertical soundings and weather conditions at the site. FT NOy mixing ratios were greater than or equal to 280 pptv and greater than or equal to 400 pptv during these two periods. The median clear-sky FT NO level during the hour centered on solar noon was 16 pptv. A mass balance model considering FT/MBL exchange and MBL removal processes is used to find the NOy MBL effective first-order loss lifetime (similar to 1.2 days) and the NOy MBL e-folding response time due to both effective first-order loss processes and subsidence-induced ventilation of the MBL (similar to 0.9 days). The apparent rapid loss of MBL NOy implies that it will respond rapidly to changes in the overlying FT, but that correlations of NOy with trace gases with slower MBL removal, such as O-3 and CO, will be degraded within the subsidence-influenced MEL. C1 Michigan Technol Univ, Dept Civil & Environm Engn, Houghton, MI 49931 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Peterson, MC (reprint author), Michigan Technol Univ, Dept Civil & Environm Engn, 1400 Townsend Dr, Houghton, MI 49931 USA. EM mpeters@mtu.edu; reh@mtu.edu; parrish@al.noaa.gov; oltmans@cmdl.noaa.gov RI Parrish, David/E-8957-2010 OI Parrish, David/0000-0001-6312-2724 NR 41 TC 12 Z9 12 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13489 EP 13503 DI 10.1029/97JD02307 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200029 ER PT J AU Kleinman, LI Daum, PH Lee, JH Lee, NY Weinstein-Lloyd, J Springston, SR AF Kleinman, LI Daum, PH Lee, JH Lee, NY Weinstein-Lloyd, J Springston, SR TI Photochemistry of O-3 and related compounds over southern Nova Scotia SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHEASTERN UNITED-STATES; PHOTOSTATIONARY STATE; HYDROGEN-PEROXIDE; MODEL SIMULATIONS; OZONE FORMATION; RURAL SITE; BUDGET; SUMMER; TROPOSPHERE; ATLANTIC AB Photochemical model calculations have been performed for air masses encountered by the National Research Council's Twin Otter aircraft during the 1993 summer North Atlantic Regional Experiment (NARE) intensive. These calculations use observed values of O-3, NOy, CO, and hydrocarbons as constraints: NO is determined using the ratio NO/NOy measured from the National Center for Atmospheric Research King Air under comparable circumstances. Measurements over coastal locations indicate photochemically aged air masses with relatively low concentrations of NO and an OH reactivity that is dominated by CO and CH4. Samples over land have higher NO and an OH reactivity that is dominated by isoprene. Ozone production rates and H2O2 concentrations are analyzed using radical budget arguments that are applicable to low NOx conditions. The ozone production rate, P(O-3), is predicted to be proportional to Q (1/2)[NO], where Q is the production rate for free radicals. This relation explains 99% of the variance in P(O-3). Over 90% of the variance is explained by [NO] alone. P(O-3) in the coastal samples is about a factor of 4 lower than previous estimates for the eastern United States. This is a consequence of low [NO] in the air masses that are advected to Nova Scotia. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Kleinman, LI (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. EM kleinman@bnl.gov; phdaum@bnl.gov; jaihlee@bnl.gov; ynlee@bnl.gov; jollyd@bnl.gov; srs@bnl.gov NR 41 TC 9 Z9 9 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13519 EP 13529 DI 10.1029/97JD01484 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200031 ER PT J AU Duderstadt, KA Carroll, MA Sillman, S Wang, T Albercook, GM Feng, L Parrish, DD Holloway, JS Fehsenfeld, FC Blake, DR Blake, NJ Forbes, G AF Duderstadt, KA Carroll, MA Sillman, S Wang, T Albercook, GM Feng, L Parrish, DD Holloway, JS Fehsenfeld, FC Blake, DR Blake, NJ Forbes, G TI Photochemical production and loss rates of ozone at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC OZONE; UNITED-STATES; PHOTOSTATIONARY STATE; AIRCRAFT MEASUREMENTS; HYDROGEN-PEROXIDE; ORGANIC-COMPOUNDS; DRY DEPOSITION; RURAL SITE; ATMOSPHERE; PACIFIC AB Three weeks of summertime surface-based chemical and meteorological observations at Sable Island, Nova Scotia during the North Atlantic Regional Experiment (NARE) 1993 summer intensive are used to study instantaneous photochemical production and loss rates of ozone by means of a numerical photochemical model. Results are most sensitive to the averaging scheme of data used to constrain the model and the ambient variability of the measurements. Model simulations driven by a time series of 5 min averaged data, most representative of the chemistry at the site, yield an average net photochemical ozone production of 3.6 ppbv/d. Estimates of net ozone production designed to filter out local sources, by using 1000-1400 LT median values of observations to drive the model and by excluding short-lived hydrocarbons, give values ranging from 1 to 4 ppbv/d. These positive values of net ozone production within the marine boundary layer over Sable Island demonstrate the impact of polluted continental plumes on the background photochemistry of the region during the intensive. The dominant ambient variables controlling photochemical production and loss rates of ozone at the site during the measurement campaign appear to be levels of nitrogen oxides, ozone, nonmethane hydrocarbons, and solar intensity determined by cloud cover. The model partitioning of nitrogen oxides agrees for the most part with measurements, lending credence to calculated photochemical production and loss rates of ozone as well as inferred levels of peroxy radicals not measured at the site. Discrepancies, however, often occur during episodes of intermittent cloud cover, fog, and rain, suggesting the influence of cloud processes on air masses reaching the site. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Atmospher Environm Serv, Sable Isl, NS, Canada. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RP Duderstadt, KA (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. EM kathyd@engin.umich.edu; mcarroll@umich.edu; sillman@kudzu.sprl.umich.edu RI Parrish, David/E-8957-2010; Holloway, John/F-9911-2012; Fehsenfeld, Frederick/I-4876-2013; WANG, Tao/B-9919-2014; OI Parrish, David/0000-0001-6312-2724; Holloway, John/0000-0002-4585-9594; WANG, Tao/0000-0002-4765-9377; Sillman, Sanford/0000-0001-6250-1191 NR 95 TC 13 Z9 14 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13531 EP 13555 DI 10.1029/98JD00397 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200032 ER PT J AU Jobson, BT Parrish, DD Goldan, P Kuster, W Fehsenfeld, FC Blake, DR Blake, NJ Niki, H AF Jobson, BT Parrish, DD Goldan, P Kuster, W Fehsenfeld, FC Blake, DR Blake, NJ Niki, H TI Spatial and temporal variability of nonmethane hydrocarbon mixing ratios and their relation to photochemical lifetime SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GAS-PHASE REACTIONS; RESIDENCE TIME; CHLORINE ATOMS; RATE CONSTANTS; AIR MASSES; CL-ATOMS; KINETICS; OH; TROPOSPHERE; ATMOSPHERE AB The relationship between temporal and spatial variability of C-2-C-8 nonmethane hydrocarbon mixing ratios and their HO lifetimes (tau) is presented for samples collected during the 1993 North Atlantic Regional Experiment (NARE) and from other urban and remote sites. The C-2-C-4 alkanes, acetylene and benzene typically define a trend of the form s(lnx) = A tau(-b) where slnx is the standard deviation of the In of the mixing ratio. The relationship extended over a wider range of hydrocarbons in winter. The exponent b ranged in value from 0.28 +/- 0.023 for winter urban data where C-2-C-8 hydrocarbons defined a strongly correlated trend, to 0.56 +/- 0.15 for C2-C4 hydrocarbons at a coastal site in Nova Scotia during NARE. The trends are significantly different from that given by the Junge relationship [Junge, 1974]. Data from the Azores do not display such a trend and were likely influenced by local emissions. Variance trends are a useful analytical tool for examining the validity of hydrocarbon measurements. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. York Univ, Ctr Atmospher Chem, N York, ON M3J 1P3, Canada. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Jobson, BT (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM tjobson@al.noaa.gov; dblake@orion.oac.uci.edu RI Kuster, William/E-7421-2010; Parrish, David/E-8957-2010; Fehsenfeld, Frederick/I-4876-2013; OI Kuster, William/0000-0002-8788-8588; Parrish, David/0000-0001-6312-2724; Jobson, Bertram/0000-0003-1812-9745 NR 31 TC 60 Z9 61 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13557 EP 13567 DI 10.1029/97JD01715 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200033 ER PT J AU Roberts, JM Bertman, SB Parrish, DD Fehsenfeld, FC Jobson, BT Niki, H AF Roberts, JM Bertman, SB Parrish, DD Fehsenfeld, FC Jobson, BT Niki, H TI Measurement of alkyl nitrates at Chebogue Point, Nova Scotia during the 1993 North Atlantic Regional Experiment (NARE) intensive SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CALIFORNIA CENTRAL VALLEY; ODD-NITROGEN NOY; PEROXYACETYL NITRATE; PEROXYPROPIONYL NITRATE; THERMAL-DECOMPOSITION; REACTIVE NITROGEN; ORGANIC NITRATES; NIWOT-RIDGE; AIR MASSES; METHYL NITRATE AB Measurements of six alkyl nitrates, methyl-, ethyl-, 1-propyl-, 2-propyl-, 2-butyl, and 3-pentyl nitrates, and two peroxycarboxylic nitric anhydrides, peroxyacetic nitric anhydride (PAN) and peroxypropionic nitric anhydride (PPN) were made at Chebogue Point, Nova Scotia, during the 1993 North Atlantic Regional Experiment campaign. The correlation of alkyl nitrates (RONO2) with carbon monoxide makes it clear that the chemistry at this site is being driven by continental emissions, since RONO2 compounds are known to be by-products of HC-NO, photochemistry. Comparison of the ratios of alkyl nitrates to their parent hydrocarbons to that of 2-butyl nitrate/butane showed significant deviations from trends predicted from rate constants, branching ratios, and loss rates. For ethyl nitrate this deviation is likely due to a combination of many additional pathways to the intermediate peroxy radical from the decomposition of larger alkoxy radicals. The propyl nitrates showed trends that differed from one another; 2-propyl nitrate was a factor of 2 to 3 higher than predicted, while 1-propylnitrate was a factor of 8 to 10 higher than predicted. The trend of 3-pentyl nitrate/pentane was relatively close (about 50% lower) to the predicted trend. The relationship between PAN and PPN showed unexpectedly high ratios of PPN to PAN in air masses coming from the south and west of the site, implying a slight local source of PPN. C1 NOAA, Aeron Lab, ERL, Boulder, CO 80303 USA. York Univ, Dept Chem, Toronto, ON M3J 2R7, Canada. York Univ, Ctr Atmospher Chem, Toronto, ON M3J 2R7, Canada. NOAA, Cooperat Inst Res Environm Sci, Boulder, CO USA. Univ Colorado, Boulder, CO 80309 USA. RP Roberts, JM (reprint author), NOAA, Aeron Lab, ERL, 325 Broadway, Boulder, CO 80303 USA. EM jr@al.noaa.gov; bertman@wmich.edu RI Roberts, James/A-1082-2009; Parrish, David/E-8957-2010; Fehsenfeld, Frederick/I-4876-2013; OI Roberts, James/0000-0002-8485-8172; Parrish, David/0000-0001-6312-2724; Jobson, Bertram/0000-0003-1812-9745 NR 57 TC 42 Z9 42 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13569 EP 13580 DI 10.1029/98JD00266 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200034 ER PT J AU Roberts, JM Bertman, SB Jobson, T Niki, H Tanner, R AF Roberts, JM Bertman, SB Jobson, T Niki, H Tanner, R TI Measurement of total nonmethane organic carbon (C-y): Development and application at Chebogue Point, Nova Scotia, during the 1993 North Atlantic Regional Experiment campaign SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GLOBAL TROPOSPHERE; ATMOSPHERE; EMISSIONS; MONOXIDE; NITROGEN; OZONE AB A technique was developed for the measurement of total nonmethane organic carbon (C-y) in the gas phase based on cryogenic collection, preseparation of CO, CH4, and CO2, conversion of all carbon to CH4, and measurement by flame ionization detector. Collection and recovery efficiencies were found to be essentially quantitative for C-2-C-7 hydrocarbons and better than 95 and 93% for methanol and formaldehyde, respectively. CO2 prevented the measurement of the C-2 hydrocarbons in atmospheric samples, and system response to ambient water vapor limited the precision of the measurement at very low C-y. The measurement system had an estimated uncertainty of 10% at ambient mixing ratios of 100 ppb C, and a detection limit of between 5 and 7 ppb C. C-y was measured in Boulder, Colorado, during June of 1993 and at Chebogue Point, Nova Scotia, during the North Atlantic Regional Experiment intensive campaign, August to September 1993. C-y values ranged from several hundred ppb C to 11 ppb C in Boulder, and from 177 to below 5 ppb C at Chebogue Point, with medians of 55 and 11 ppbC, respectively. C-y was found to correlate with both CO and O-3 at higher levels of those two pollutants. The sum of C-y and the C-2 hydrocarbons was virtually always equal to or greater than the sum of the hydrocarbons. Several exceptions to this occurred when high HC values were observed in cannister samples but not C-y measurements. These instances were attributed to short-term perturbations from local sources. There was a net difference between total nonmethane organic carbon and the sum of hydrocarbons and carbonyls of 3.5 +/- 7.8 ppb C overall. This difference appears to be broadly correlated with anthropogenic pollution. There does not appear to be a significantly large reservoir of reactive carbon unaccounted for by hydrocarbon or carbonyl measurements. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Tennessee Valley Author, CEB Environm Res Ctr 201, Muscle Shoals, AL 35660 USA. RP Roberts, JM (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM jr@al.noaa.gov; steven.bertman@wmich.edu; tjobson@al.noaa.gov; rltanner@tva.gov RI Roberts, James/A-1082-2009 OI Roberts, James/0000-0002-8485-8172 NR 27 TC 14 Z9 14 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13581 EP 13592 DI 10.1029/97JD02240 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200035 ER PT J AU Lin, X Trainer, M Hsie, EY AF Lin, X Trainer, M Hsie, EY TI A modeling study of tropospheric species during the North Atlantic Regional Experiment (NARE) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLOUD TRANSPORT; CARBON-MONOXIDE; BOUNDARY-LAYER; UNITED-STATES; TRACE GASES; OZONE; AIR; NITROGEN AB A three-dimensional regional chemistry model is used to simulate distributions of a number of tropospheric species over eastern North America and the western North Atlantic for August of 1993. The model is tested by comparisons of the results with observations obtained at two ground stations in Nova Scotia, Canada, and on board two aircraft. The modeled mixing ratios of CO and O-3 as well as the ratio of Delta O-3/Delta CO at the two ground sites are in satisfactory agreement with the observations. More than 90% of the aircraft-observed O-3 and CO and 75% of NOy can be reproduced by the model with relative differences less than 50 and 100%, respectively. The model-simulated correlations among O-3, CO, and NOy are dose to the aircraft observations. Most of the model-calculated vertical distributions of these species have the same pattern as the observations. The calculated profiles coincide with the observations with mean discrepancies of about 25, 30, and 100% for O-3, CO, and NOy, respectively. The model-calculated wind speeds are in good agreement with the observations. Continental plumes within the model may be spatially off by a few hundred kilometers or temporally off by several hours. Possible inaccuracy in side boundary conditions and some difficulties in capturing small scale processes like small scale intrusion from the stratosphere and subgrid scale convective mixing are possible explanations for discrepancies between chemical data and model results. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA. RP Lin, X (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM linxing@al.noaa.gov; trainer@al.noaa.gov; hsie@al.noaa.gov RI Trainer, Michael/H-5168-2013; Hsie, Eirh-Yu/I-4449-2013 OI Hsie, Eirh-Yu/0000-0003-3934-9923 NR 41 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1998 VL 103 IS D11 BP 13593 EP 13613 DI 10.1029/98JD00285 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZV631 UT WOS:000074325200036 ER PT J AU Mountain, RD AF Mountain, RD TI Shear viscosity and dielectric constant of liquid methanol SO MOLECULAR PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; COMPUTER-SIMULATION; COEXISTENCE CURVE; WATER AB Molecular dynamics simulations for liquid methanol are used to estimate the dielectric constant and shear viscosity. A rigid, fixed-charge three-site model is used. Three similar models that have been proposed provide estimates for these liquid methanol properties that are within +/-30% of the experimental values.This is probably adequate for simulations where methanol is a solvent and induced polarization beyond a mean-field level is not a factor. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Mountain, RD (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. EM RMountain@nist.gov NR 28 TC 5 Z9 6 U1 2 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD JUN 20 PY 1998 VL 94 IS 3 BP 435 EP 437 DI 10.1080/002689798167935 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZV748 UT WOS:000074337200003 ER PT J AU Hanson, DR AF Hanson, DR TI Reaction of ClONO2 with H2O and HCl in sulfuric acid and HNO3/H2SO4/H2O mixtures SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID STRATOSPHERIC TEMPERATURES; HETEROGENEOUS REACTIONS; CHLORINE NITRATE; NITRIC-ACID; SURFACES; WATER; HOCL; H2SO4/HNO3/H2O; SOLUBILITIES; AEROSOLS AB Measurements of the reaction probabilities (gamma) for ClONO2 onto sulfuric acid solutions at 200-270 K are described. ClONO2 uptake due to reaction with H2O and with HCl in H2SO4 solutions (45-55 wt %) was investigated at 203-205 K. ClONO2 hydrolysis was also investigated on 36.5, 40, and 75 wt % sulfuric acid solutions over a range of temperatures. The measured gamma are generally in good agreement with previously reported values. In addition, the solubility of HCl was determined for 45 and 50 wt % sulfuric acid from 200 to 225 K. The uptake of ClONO2 onto small sulfuric acid particles was studied resulting in a lower limit to the sticking coefficient of 0.5. ClONO2 reaction probabilities were also measured on H2SO4 solutions containing significant amounts of HNO3. In opposition to previous reports, HNO3 was found to have a significant effect on gamma for ClONO2: it is as low as one-half of that expected for the comparable HNO3-free solutions. The measured gamma on sulfuric acid solutions at 203 +/- 2 K are discussed in terms of solubility, diffusivity, and bulk and surface reactions. Within this framework, the measured gamma were fit as a function of H2SO4 and HCl content, thus allowing for the measurements to be extrapolated to atmospheric conditions. C1 CIRES, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Hanson, DR (reprint author), CIRES, Boulder, CO 80303 USA. NR 42 TC 52 Z9 52 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 18 PY 1998 VL 102 IS 25 BP 4794 EP 4807 DI 10.1021/jp972767s PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZV964 UT WOS:000074360000006 ER PT J AU Forsyth, WR Gilson, MK Antosiewicz, J Jaren, OR Robertson, AD AF Forsyth, WR Gilson, MK Antosiewicz, J Jaren, OR Robertson, AD TI Theoretical and experimental analysis of ionization equilibria in ovomucoid third domain SO BIOCHEMISTRY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; CONTINUUM ELECTROSTATIC MODEL; 3RD DOMAIN; PH-DEPENDENCE; MACROMOLECULAR STRUCTURES; IONIZABLE GROUPS; LYSINE RESIDUES; PK(A) VALUES; SIDE-CHAIN; PROTEINS AB 2D-NMR experiments were used to determine the pK(a) values ranging from 8.0 to greater than or equal to 11.1 of seven basic residues in turkey ovomucoid third domain (OMTKY3) and were compared to values predicted as described by Antosiewicz et al. [(1996) Biochemistry 35, 7819-7833]. Lys 13, 29, and 34 were previously attributed with increasing the acidity of numerous acidic residues [Schaller, W., and Robertson, A. D. (1995) Biochemistry, 34, 4714-4723]. These interactions were expected to raise the pK(a) values of those basic groups; however, the pK(a) values of Lys 13 and 34 are less than the model compound values. The pK(a) values of the other basic residues are greater than the model compound values and, unlike the acidic residues, all are surprisingly insensitive to salt. While the calculations properly predict the direction of most of the pK(a) shifts and provide valuable insight into the possible molecular origins of the interactions that perturb pK(a) values, there is a tendency to overestimate the magnitude of the shifts and their salt dependence. Interestingly, the shapes of both the calculated and observed transitions are often more complex than expected for a simple titration, suggesting that pK(a) values at many sites are changing during the transition. Differences between predicted and experimental pK(a) values and titration profiles for some residues may be due to as yet uncharacterized structural changes at the extremes of pH. C1 Univ Iowa, Dept Biochem, Iowa City, IA 52242 USA. NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Warsaw, Dept Biophys, PL-02089 Warsaw, Poland. RP Robertson, AD (reprint author), Univ Iowa, Dept Biochem, Iowa City, IA 52242 USA. RI Antosiewicz, Jan/G-1308-2011 FU NIGMS NIH HHS [GM 46869, GM 54053] NR 65 TC 55 Z9 55 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 16 PY 1998 VL 37 IS 24 BP 8643 EP 8652 DI 10.1021/bi980187v PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZV930 UT WOS:000074356000005 PM 9628726 ER PT J AU Rose, CS Nunnallee, EP AF Rose, CS Nunnallee, EP TI A study of changes in groundfish trawl catching efficiency due to differences in operating width, and measures to reduce width variation SO FISHERIES RESEARCH LA English DT Article DE survey; trawl; catchability; constraint AB The influence of trawl width on the ability of a survey trawl to capture groundfish was tested by comparing catch rates between paired tows with and without a constraint line that reduced the operating width of the trawl. The vertical distribution of fish near and above the seafloor was recorded with an echo sounder to test for the incidence of fish diving into the path of the trawl during the tows. Arrowtooth flounder (Atheresthes stomias), flathead sole (Hippoglossoides elassodon) and walleye pollock (Theragra chalcogramma) were captured at higher rates (fish per area swept) by a survey trawl fished in the restricted (narrow) configuration. The greatest difference occurred for pollock. The difference in catch rates was consistent across size groups within each species. Correlations detected between catch rates of pollock and echo-integration values for targets well above the trawl height indicated that some of these fish may have been diving from midwater into the path of the trawl. Differences between the correlation patterns with and without constraint lines indicate that the diving behavior may be affected by the presence of the line. Published by Elsevier Science B.V. C1 Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, Seattle, WA 98115 USA. RP Rose, CS (reprint author), Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 14 TC 23 Z9 23 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JUN 15 PY 1998 VL 36 IS 2-3 BP 139 EP 147 DI 10.1016/S0165-7836(98)00099-X PG 9 WC Fisheries SC Fisheries GA 100HP UT WOS:000074811000007 ER PT J AU Peterson, WK Tung, YK Carlson, CW Clemmons, JH Collin, HL Ergun, RE Fuselier, SA Kletzing, CA Klumpar, DM Lennartsson, OW Lepping, RP Maynard, NC McFadden, JP Onsager, TG Peria, WJ Russell, CT Shelley, EG Tang, L Wygant, J AF Peterson, WK Tung, YK Carlson, CW Clemmons, JH Collin, HL Ergun, RE Fuselier, SA Kletzing, CA Klumpar, DM Lennartsson, OW Lepping, RP Maynard, NC McFadden, JP Onsager, TG Peria, WJ Russell, CT Shelley, EG Tang, L Wygant, J TI Simultaneous observations of solar wind plasma entry from FAST and POLAR SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETOSPHERE; INSTRUMENT; MISSION AB On November 15, 1996, NASA FAST and POLAR satellites obtained data in the cusp/cleft region for extended intervals. POLAR sampled a narrow range of local times. FAST observed cusp/cleft plasma for more than 5 hours in local time. At 07:51 UT the satellites were in near magnetic conjunction, and the interplanetary magnetic field was steady for an extended interval before this time. We confirm prior observations that show solar wind plasma often enters the magnetosphere over extended regions of local time. For the one hour interval of steady solar wind conditions when POLAR encountered cusp/cleft plasma, irregularly spaced ion injections interspersed with intervals of nearly constant cusp/cleft ion fluxes were observed. The data are consistent with temporal variations in the reconnection rate. At the time of the near conjugate observations the data suggest that solar wind plasma entered the magnetosphere over an extended region of the magnetopause, i.e. not in small discontinuous patches. C1 Lockheed Martin, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Aerosp Corp, El Segundo, CA 90245 USA. Univ Iowa, Iowa City, IA 52242 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Mission Res Corp, Nashua, NH 03060 USA. NOAA, Space Environm Lab, Boulder, CO 80309 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ New Hampshire, Durham, NH 03824 USA. Univ Minnesota, Minneapolis, MN 55455 USA. RP Peterson, WK (reprint author), Lockheed Martin, 3251 Hanover St, Palo Alto, CA 94304 USA. EM pete@spasci.com RI Peterson, WK/A-8706-2009; OI Peterson, WK/0000-0002-1513-6096; Clemmons, James/0000-0002-5298-5222; Kletzing, Craig/0000-0002-4136-3348; Russell, Christopher/0000-0003-1639-8298 NR 18 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1998 VL 25 IS 12 BP 2081 EP 2084 DI 10.1029/98GL00668 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZV204 UT WOS:000074280800018 ER PT J AU Soden, BJ Ramaswamy, V AF Soden, BJ Ramaswamy, V TI Variations in atmosphere-ocean solar absorption under clear skies: A comparison of observations and models SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE; RADIATION; CLOUDS; SATELLITE; RETRIEVAL; CLIMATE; BUDGET; WATER AB Satellite observations of the clear-sky, atmosphere-ocean solar absorption are compared to simulations from a global climate model. Variations in solar absorption are analyzed under conditions of constant solar geometry to highlight spatially coherent features. From this analysis, the observed zonal and interannual variability in clear-sky solar absorption is shown to be substantially larger than that predicted by the model. Explanations for the greater observed variability are considered in terms of aerosols, surface wind effects, and water vapor. RP Soden, BJ (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. EM bjs@gfdl.gov; vr@gfdl.gov NR 23 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1998 VL 25 IS 12 BP 2149 EP 2152 DI 10.1029/98GL01509 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZV204 UT WOS:000074280800036 ER PT J AU McCormack, JP Miller, AJ Nagatani, R Fortuin, JPF AF McCormack, JP Miller, AJ Nagatani, R Fortuin, JPF TI Interannual variability in the spatial distribution of extratropical total ozone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Quasi-stationary planetary waves induce zonal asymmetries in wintertime extratropical total ozone fields with typical magnitudes of 30 to 60 Dobson Units. Year-to-year changes in the zonally asymmetric component of monthly mean total ozone fields are examined using both the Nimbus 7 TOMS record (1979 - 1993) and the combined Nimbus 7, NOAA 11, and NOAA 9 SBUV(2) records (1979 - 1996), focusing on northern extratropical latitudes in February and southern extratropical latitudes in October. A simple model based on the linearized ozone mixing ratio continuity equation, in which the dynamics are specified from NCEP reanalysis geopotential height and temperature fields, is used to simulate the interannual variability in the spatial distribution of total ozone. Model estimates of the wave-induced variability in total ozone fields agree well, both qualitatively and quantitatively, with the variability observed in lower-resolution SBUV(2) and higher-resolution TOMS records, with the exception of certain years at high southern latitudes in October. Disagreement during these years is related to the displacement of the springtime ozone minimum from over the pole by enhanced planetary wave activity. C1 NOAA, Natl Weather Serv, Climate Predict Ctr, Washington, DC 20233 USA. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. RP McCormack, JP (reprint author), NOAA, Natl Weather Serv, Climate Predict Ctr, Washington, DC 20233 USA. EM jmcc@climon.wwb.noaa.gov OI McCormack, John/0000-0002-3674-0508 NR 18 TC 7 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1998 VL 25 IS 12 BP 2153 EP 2156 DI 10.1029/98GL01548 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZV204 UT WOS:000074280800037 ER PT J AU Tanioka, Y Gonzalez, FI AF Tanioka, Y Gonzalez, FI TI The Aleutian earthquake of June 10, 1996 (Mw 7.9) ruptured parts of both the Andreanof and Delarof segments SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEISMICITY; ISLANDS; ARC; ALASKA AB The epicenter of the Aleutian earthquake of June 10, 1996, is located in the Delarof segment where a large subduction earthquake is expected. However, the aftershock area of the earthquake is not only in the Delarof segment but also in the Andreanof segment where the 1986 Andreanof earthquake occurred previously. We estimate the fault parameters of the 1996 earthquake by numerically computing the tsunami and comparing the waveforms with that recorded at Adak. The fault width is 30 km or less, and the average slip is about 4 m. The observed far-field tsunamis around the Pacific are also explained by the synthetic tsunami computed using the above fault parameters. The results indicate that the 1996 earthquake ruptured parts of both the Delarof and Andreanof segments. However, the 1996 earthquake did not rupture the region of the largest moment release by the 1986 earthquake. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98125 USA. Meteorol Res Inst, Seismol & Volcanol Res Dept, Tsukuba, Ibaraki 305, Japan. RP Tanioka, Y (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98125 USA. NR 20 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1998 VL 25 IS 12 BP 2245 EP 2248 DI 10.1029/98GL01578 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZV204 UT WOS:000074280800060 ER PT J AU Lugez, CL Jacox, ME King, RA Schaefer, HF AF Lugez, CL Jacox, ME King, RA Schaefer, HF TI Experimental and ab initio study of the infrared spectra of ionic species derived from SF6 and SF4 and trapped in solid neon SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VALENCE ELECTRONIC STATES; VIBRATIONAL-SPECTRA; GAS-PHASE; SULFUR-HEXAFLUORIDE; MATRIX-ISOLATION; 2 ISOMERS; MOLECULE REACTIONS; GAUSSIAN-2 THEORY; MOLLER-PLESSET; CLUSTER IONS AB When a Ne:SF6 mixture is subjected to Penning ionization and/or photoionization by neon atoms in their first excited states, between 16.6 eV and 16.85 eV, and the products are rapidly frozen at approximately 5 K, the infrared spectrum of the resulting deposit includes prominent absorptions of SF4 and SF5. Other prominent product absorptions are assigned to SF5+ and SF5-, and one absorption is tentatively assigned to SF6-. Similar experiments on a Ne:SF4 sample yield SF4+, SF3+, and SF4-, as well as some F2SO+ and F-2... SO, derived from F2SO impurity. The spectroscopic identifications of the SFn cations and anions are aided by the results of ab initio calculations. Because the vertical electron detachment energy of SF5- is exceptionally high, this species is stable on;unfiltered mercury-arc irradiation of the deposit. (C) 1998 American Institute of Physics. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Georgia, Ctr Computat Quantum Chem, Athens, GA 30602 USA. RP Lugez, CL (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 76 TC 30 Z9 30 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1998 VL 108 IS 23 BP 9639 EP 9650 DI 10.1063/1.476440 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FU UT WOS:000075256100006 ER PT J AU Walsh, EJ Vandemark, DC Friehe, CA Burns, SP Khelif, D Swift, RN Scott, JF AF Walsh, EJ Vandemark, DC Friehe, CA Burns, SP Khelif, D Swift, RN Scott, JF TI Measuring sea surface mean square slope with a 36-GHz scanning radar altimeter SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID BACKSCATTER; WAVES; SPECTRUM AB Values of sea surface mean square slope (mss) computed from the backscattered power falloff with incidence angle measured by an airborne 36-GHz scanning radar altimeter are presented. When the mss values are plotted against the 10-m wind speed (extrapolated from the 46- to 110-m aircraft height), for wind speeds up to 7 m s(-1) the values scatter about a curve which is scaled from that obtained by Wu [1990] by a factor of 0.85. Wu's result was a reanalysis of the optical measurements of Cox and Munk [1954]. The offset between the microwave and optical curves is reasonable because one would expect the surface to appear smoother to the microwave wavelength than to the optical. This is unlike the mss values inferred from absolute power measurements at nadir by 14-GHz satellite altimeters, which indicate a higher mss under light wind conditions than the optical measurements indicate. For wind speeds below 7 m s(-1) the peak of the backscattered power distribution is observed at nadir, but for higher speeds the peak shifts off-nadir in the downwind direction. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Observat Sci Branch,Wallops Flight Facil, Wallops Island, VA 23337 USA. Univ Calif Irvine, Dept Mech Engn, Irvine, CA 92717 USA. EG&G Serv Inc, Wallops Flight Facil, Wallops Island, VA 23337 USA. RP Walsh, EJ (reprint author), NOAA, Environm Technol Lab, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. RI Burns, Sean/A-9352-2008 OI Burns, Sean/0000-0002-6258-1838 NR 33 TC 33 Z9 34 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1998 VL 103 IS C6 BP 12587 EP 12601 DI 10.1029/97JC02443 PG 15 WC Oceanography SC Oceanography GA ZU093 UT WOS:000074160900001 ER PT J AU Walsh, EJ Hagan, DE Rogers, DP Weller, RA Fairall, CW Friehe, CA Burns, SP Khelif, D Vandemark, DC Swift, RN Scott, JF AF Walsh, EJ Hagan, DE Rogers, DP Weller, RA Fairall, CW Friehe, CA Burns, SP Khelif, D Vandemark, DC Swift, RN Scott, JF TI Observations of sea surface mean square slope under light wind during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article AB Observations of sea surface mean square slope.(mss) were made with a scanning radar altimeter (SRA) from a low-flying research aircraft on a light-wind day during the Tropical Ocean-global Atmosphere Coupled Ocean-Atmosphere Response Experiment. Wind speed (measured at 60- to 90-m height and extrapolated to the 10-m level) and mss were found to be positively correlated, with correlation coefficients in some cases as high as those obtained for wind speed measurements on adjacent aircraft flying wingtip to wingtip with a 100-m lateral separation of their fuselages. The SRA measurements suggest a much larger azimuthal asymmetry in mss at 36 GHz than was observed in the seminal Cox and Munk optical experiment; the SRA measurements showed a crosswind-to-upwind ratio as low as of 0.26 at 1.8 m s(-1) compared to the typical value of 0.8 for Cox and Munk. For higher wind speed the mss becomes more isotropic. The data suggest that waves generated by a wind speed less than 2 m s(-1) are restricted to the downwind direction. The crosswind-to-upwind ratio would probably have been even lower had it not been for an isotropic background mss caused by an assortment of swell. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Observat Sci Branch,Wallops Flight Facil, Wallops Island, VA 23337 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ Calif Irvine, Dept Mech Engn, Irvine, CA 92717 USA. EG&G Serv Inc, Wallops Flight Facil, Wallops Island, VA 23337 USA. RP Walsh, EJ (reprint author), NOAA, Environm Technol Lab, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. RI Burns, Sean/A-9352-2008 OI Burns, Sean/0000-0002-6258-1838 NR 18 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1998 VL 103 IS C6 BP 12603 EP 12612 DI 10.1029/98JC00780 PG 10 WC Oceanography SC Oceanography GA ZU093 UT WOS:000074160900002 ER PT J AU Walsh, EJ Pinkel, R Hagan, DE Weller, RA Fairall, CW Rogers, DP Burns, SP Baumgartner, M AF Walsh, EJ Pinkel, R Hagan, DE Weller, RA Fairall, CW Rogers, DP Burns, SP Baumgartner, M TI Coupling of internal waves on the main thermocline to the diurnal surface layer and sea surface temperature during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article AB Patterns in sea surface temperature (SST) on 5-km scales were observed from low-flying research aircraft on a light wind day during the Tropical Ocean-Global Atmosphere Coupled Ocean Atmosphere Response Experiment. An inverse trend was observed between the SST and the sea surface mean square slope (mss). However, low correlation coefficients indicate that the dominant process causing the spatial variation of SST under these light wind conditions is neither well controlled by the wind speed nor well monitored by the mss. The SST spatial pattern persisted for at least 1 hour and propagated toward the NE at about 1 m s(-1), a factor of 1.6 faster than the speed of the surface current. Coupling between internal gravity waves propagating on the seasonal thermocline and the diurnal surface layer is examined as a possible explanation for the observed SST variability in space and time. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ Calif Irvine, Dept Mech Engn, Irvine, CA 92717 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Observat Sci Branch, Wallops Island, VA 23337 USA. RP Walsh, EJ (reprint author), NOAA, Environm Technol Lab, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. RI Burns, Sean/A-9352-2008 OI Burns, Sean/0000-0002-6258-1838 NR 26 TC 13 Z9 13 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1998 VL 103 IS C6 BP 12613 EP 12628 DI 10.1029/98JC00894 PG 16 WC Oceanography SC Oceanography GA ZU093 UT WOS:000074160900003 ER PT J AU Oey, LY AF Oey, LY TI Subtidal energetics in the Faroe-Shetland Channel: Coarse-grid model experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SCOTTISH CONTINENTAL-SHELF; ROCKALL CHANNEL; SLOPE CURRENT; SEA; SIMULATION; OCEAN; FLUX; WEST AB This paper compares various forcings that contribute to the regional subtidal energetics of the ocean passageway northwest of Scotland, in the Faroe-Shetland Channel (FSC), where inflow of warm and saline North Atlantic water mixes with outflow of cold and less-saline Nordic Sea waters. On the scales resolvable by the (coarse) grid sizes of Delta x = Delta y = 20 km and 20 vertical sigma layers, changes in currents' energetics caused by wind, Atlantic inflow (doubled), decreased horizontal mixing, surface heat flux, and open-boundary density specifications were 28, 43, 40, 16, and 5%, respectively, of the kinetic energy of a background quasi-steady slope current. The subtidal currents were not sensitive to the atmospheric pressure forcing and the surface relaxation to monthly climatology nor to the inclusion of additional (apart from M2) tidal constituents K1, O1, and S2. Wind-induced motions resulted in transport fluctuations of about 1.5 Sv in the FSC, maximum in winter and minimum in summer, and alongshore and cross-shore current variances of 0.1 and 0.05 m s(-1), respectively, in fair agreement with observations. Spectral peaks at periods of 23-30 hours were found and were shown to correspond to resonant continental shelf waves in the channel. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Oey, LY (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, Sayre Hall,Forrestal Campus, Princeton, NJ 08544 USA. EM lyo@splash.princeton.edu NR 34 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1998 VL 103 IS C6 BP 12689 EP 12708 DI 10.1029/98JC00786 PG 20 WC Oceanography SC Oceanography GA ZU093 UT WOS:000074160900009 ER PT J AU Gbah, MB Jacobs, SJ Meadows, GA Bratkovich, A AF Gbah, MB Jacobs, SJ Meadows, GA Bratkovich, A TI A model of the thermal bar circulation in a lone basin SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID STRATIFIED FLUIDS; LAKE; TEMPERATURE; SURFACE AB A thermal bar is defined here as a zone of descending water at or near the fresh water temperature of maximum density. In the present study, we model physical properties such as velocity, temperature, turbulent fluxes, time of onset, and migration speed of the thermal bar in an idealized basin. Unlike models using prescribed eddy viscosity and diffusivity coefficients: our model uses a second-order turbulence closure scheme to model mixing due to turbulence. The only inputs in the calculation are the surface wind, the surface heat flux, and the initial state of the fluid. Numerical simulations of the resulting circulation are presented for flow in a long rotating basin under prescribed surface heat and wind conditions. The results show the influence of the relative magnitudes of mechanical and thermal forcing on the circulation. A comparison with field observations shows reasonable agreement between computed and measured bar migration speeds. The time necessary for the formation of the bar is computed, and is found to depend on the surface forcing. C1 Univ Michigan, Cooperat Inst Limnol & Ecosyst Res, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Naval Architecture & Marine Engn, Ann Arbor, MI 48109 USA. Great Lakes Environm Res Lab, Ann Arbor, MI USA. RP Gbah, MB (reprint author), Univ Michigan, Cooperat Inst Limnol & Ecosyst Res, 2200 Bonisteel Blvd, Ann Arbor, MI 48109 USA. EM gbah@engin.umich.edu; sjj@engin.umich.edu; ows@engin.umich.edu NR 40 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1998 VL 103 IS C6 BP 12807 EP 12821 DI 10.1029/98JC00581 PG 15 WC Oceanography SC Oceanography GA ZU093 UT WOS:000074160900016 ER PT J AU Wang, PS Ferguson, MM Eng, G Bentz, DP Ferraris, CF Clifton, JR AF Wang, PS Ferguson, MM Eng, G Bentz, DP Ferraris, CF Clifton, JR TI H-1 nuclear magnetic resonance characterization of Portland cement: molecular diffusion of water studied by spin relaxation and relaxation time-weighted imaging SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ALUMINA GREEN COMPACTS; NMR CHARACTERIZATION; POROUS SILICA; HYDRATION; PASTES; MODEL AB Water molecular dynamics in a hardened Portland cement were characterized by proton Fourier transform nuclear magnetic resonance (NMR) at 400 MHz. Three different types of water molecule (physically bound, chemically bound and porous trapped) were observed. When the hardened cement sample was heated at 105 degrees C, the physically bound water diffused out of the sample as a function of the heating time while the chemically bound water remained in a stable form. A trace amount of the porously trapped water was also detected to remain in the cavities of the hardened cement even after heating for up to 20 h at th is temperature. The loss of the physically bound water proved to be a diffusion-controlled process as evidenced from the NMR data and from a gravimetric technique. A Fake doublet was observed in the NMR spectra. This is a result of the oscillation of the water molecules with hindered molecular motions due to their entrapment in the cement pores. Soaking the dried samples in water resulted in the diffusion of water back into the hardened cement as physically bound water. Nuclear spin-spin relaxation time, T-2-weighted imaging showed that the distribution of the physically bound water inside the cylindrical sample formed a doughnut shape after overnight soaking. The residual air in the cement pores may have slowed down the diffusion rate of the water molecules back into the dried cement. (C) 1998 Kluwer Academic Publishers. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wang, PS (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM pu.wang@nist.gov NR 27 TC 16 Z9 16 U1 0 U2 13 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JUN 15 PY 1998 VL 33 IS 12 BP 3065 EP 3071 DI 10.1023/A:1004331403418 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 149DV UT WOS:000077590600011 ER PT J AU Montgomery, MT Franklin, JL AF Montgomery, MT Franklin, JL TI An assessment of the balance approximation in hurricanes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID POTENTIAL-VORTICITY; CYCLONE; GLORIA AB The validity of the traditional balance approximation for the asymmetric flow above the boundary layer generally in hurricanes is examined here. Scaling considerations of the divergence equation show that the validity of the balance approximation hinges on the smallness of the nondimensional product (delta(n)'/zeta(n)')x(n (v) over bar/<(eta)over bar>r). The first term represents the ratio of asymmetric horizontal divergence to asymmetric vertical vorticity for azimuthal wavenumber n, while the second term represents a Rossby number based upon the azimuthal mean tangential wind and absolute vertical vorticity of the hurricane vortex. Wind observations of Hurricane Gloria (1985) indicate that this product is not at all small in the near-vortex region (several hundred kilometers beyond the radius of maximum tangential winds) where asymmetric convergence forced by surface friction and cumulus convection is typically large. Although the Gloria observations represent only a single case, there are dynamical reasons to expect this product to be O(1)just above the hurricane boundary layer in steadily translating hurricanes. The meteorological relevance of these results to the problem of balance dynamics in hurricanes is briefly discussed. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Montgomery, MT (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NR 15 TC 21 Z9 23 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 15 PY 1998 VL 55 IS 12 BP 2193 EP 2200 DI 10.1175/1520-0469(1998)055<2193:AAOTBA>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZU121 UT WOS:000074164400004 ER PT J AU Woicik, JC Miyano, KE King, CA Johnson, RW Pellegrino, JG Lee, TL Lu, ZH AF Woicik, JC Miyano, KE King, CA Johnson, RW Pellegrino, JG Lee, TL Lu, ZH TI Phase-correct bond lengths in crystalline GexSi1-x alloys SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; RANDOM SOLID-SOLUTIONS; SEMICONDUCTOR ALLOYS; SI1-XGEX ALLOYS; LOCAL-STRUCTURE; RELAXATION; STABILITY AB Extended x-ray absorption fine structure performed at the Ge K edge has found the Ge-Ge and Ge-Si bond lengths in a series of crystalline GexSi1-x alloys (x less than or equal to 0.5) to be compositionally dependent. This accurate measurement was made possible by utilizing the experimentally derived Ge-Si atomic phase shift from the isoelectronic compounds AlAs and Gap. Strain and Coulomb contributions to the bond lengths are also considered. C1 NIST, Gaithersburg, MD 20899 USA. CUNY Brooklyn Coll, Dept Phys, Brooklyn, NY 11210 USA. Lucent Technol, AT&T Bell Labs, Murray Hill, NJ 07974 USA. Northwestern Univ, Dept Mat Sci, Evanston, IL 60208 USA. Natl Res Council Canada, Ottawa, ON K1A 0R6, Canada. RP Woicik, JC (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 31 TC 43 Z9 43 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 1998 VL 57 IS 23 BP 14592 EP 14595 DI 10.1103/PhysRevB.57.14592 PG 4 WC Physics, Condensed Matter SC Physics GA ZV141 UT WOS:000074273500007 ER PT J AU Phillips, JC Rasaiah, JC Hubbard, JB AF Phillips, JC Rasaiah, JC Hubbard, JB TI Comment on "Anomalous size dependence of relaxational processes" SO PHYSICAL REVIEW LETTERS LA English DT Article ID GLASS-TRANSITION; MOLECULAR-DYNAMICS; LIQUID C1 AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Univ Maine, Dept Chem, Orono, ME 04469 USA. NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 15 PY 1998 VL 80 IS 24 BP 5453 EP 5453 DI 10.1103/PhysRevLett.80.5453 PG 1 WC Physics, Multidisciplinary SC Physics GA ZU051 UT WOS:000074156300057 ER PT J AU Wang, YL Hsu, SM Jones, P AF Wang, YL Hsu, SM Jones, P TI Evaluation of thermally-sprayed ceramic coatings using a novel ball-on-inclined plane scratch method SO WEAR LA English DT Article DE plasma-sprayed; HVOF; coatings; Al2O3; ZrO2; ceramics ID WEAR PERFORMANCE; HIGH-TEMPERATURE; FRICTION AB A ball-on-inclined plane scratch test method has been developed to determine the materials responses to stresses on thermally-sprayed ceramic coatings. Material properties such as the critical damage load, damage patterns of the scratched surface and subsurface crack patterns are evaluated. Results show that when the applied load is below the critical value, then is no subsurface damage but plastic deformation occurs locally on the surface. Beyond the critical load, high velocity oxygen fuel (HVOF) sprayed Al2O3 coatings exhibit plastic deformation on the scratched surface and subsurface cracks propagating in the directions parallel to and at an angle to the sliding surface. In the case of a plasma-sprayed ZrO2 coating, beyond the critical load, cracks initiate at the surface and propagate into the subsurface at an angle about 30 degrees to the sliding surface. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wang, YL (reprint author), Iomega, 800 Tasman Dr, Milpitas, CA 95035 USA. NR 16 TC 12 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD JUN 15 PY 1998 VL 218 IS 1 BP 96 EP 102 DI 10.1016/S0043-1648(98)00182-3 PG 7 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 102YV UT WOS:000074954600011 ER PT J AU Wladkowski, BD Svensson, LA Sjolin, L Ladner, JE Gilliland, GL AF Wladkowski, BD Svensson, LA Sjolin, L Ladner, JE Gilliland, GL TI Structure (1.3 angstrom) and charge states of a ribonuclease A uridine vanadate complex: Implications for the phosphate ester hydrolysis mechanism SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID BOVINE PANCREATIC RIBONUCLEASE; REFINED CRYSTAL-STRUCTURE; LEAST-SQUARES REFINEMENT; CYTIDYLIC ACID 2'-CMP; X-RAY REFINEMENT; TRANSITION-STATE; ACTIVE-SITE; RNASE-A; NEUTRON-DIFFRACTION; SUBSTRATE BINDING AB A joint X-ray crystallographic (1.3 Angstrom resolution) and ab initio quantum mechanical analysis of a uridine vanadate-ribonuclease A complex (W-RNase A) is undertaken to probe specific aspects of the microscopic mechanism by which ribonuclease functions to catalyze the hydrolysis of its natural substrate, phosphate esters. Comparison of the structural features of the vanadate portion from the final X-ray refinement with the oxy-vanadate model compounds determined computationally provides direct evidence of the likely protonation state of the UV inhibitor bound in the active site. Specifically, the UV bound in the active site of UV-RNase A is found to be monoanionic, and the most likely source of this proton is from the active site residue His12. Together with the structural data, these results strongly suggest that even though His12 may act as the catalytic base in the first step of ale mechanism, transphosphorylation, and the catalytic acid in the second step, hydrolysis, it must also play an additional, although perhaps secondary, role in stabilizing the pentacoordinate phosphorane structure through proton transfer. On the basis of its close proximity to critical vanadate oxygen in the UV, and data obtained from a previous computational study, Lys41 is Likely to play a more intimate role in the catalytic mechanism than previously proposed, potentially acting as the catalytic base in certain cases. Two possible detailed microscopic mechanisms are presented. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Western Maryland Coll, Dept Chem, Westminster, MD 21157 USA. Univ Lund, Ctr Chem, Dept Mol Biophys, S-22100 Lund, Sweden. Chalmers Univ Technol, Dept Inorgan Chem, S-41296 Gothenburg, Sweden. Univ Gothenburg, S-41296 Gothenburg, Sweden. NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Gilliland, GL (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI Sjolin, Lennart/B-2619-2010 NR 71 TC 40 Z9 40 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 10 PY 1998 VL 120 IS 22 BP 5488 EP 5498 DI 10.1021/ja972296n PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA ZU595 UT WOS:000074213800016 ER PT J AU Bullock, OR Brehme, KA Mapp, GR AF Bullock, OR Brehme, KA Mapp, GR TI Lagrangian modeling of mercury air emission, transport and deposition: An analysis of model sensitivity to emissions uncertainty SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE mercury; atmospheric; modeling; deposition; emission ID ATMOSPHERIC MERCURY; PRECIPITATION; EXCHANGE; FOREST AB The Regional Lagrangian Model of Air Pollution (RELMAP) is used to simulate the emission, transport and diffusion, chemical transformation, and wet and dry deposition of elemental mercury gas, divalent mercury gas and particulate mercury from various point-and area-source types. A version of the RELMAP mercury model is used which separately simulates the transport and deposition of emissions from the seven point-source categories modeled. A mercury air emission inventory developed by the U.S. EPA Office of Air Quality Planning and Standards for the continental United States is used. This inventory provides estimates of the total mercury mass emitted, but does not define the chemical and physical forms of these emissions. A wide variety of emission speciations, combinations of chemical and physical forms, are evaluated with the new RELMAP mercury model. Average annual concentrations and wet and dry deposition totals are simulated for a complete calendar year. The results of the simulation are used to estimate the quantity of mercury deposited to soils and water bodies based on a variety of assumed emission speciation for the seven point-source types. An analysis of the modeling results provides some quantitative information about the sensitivity of modeling results to uncertainty in the mercury emissions speciation of modeled industrial activities, but a qualitative assessment is the primary goal. The model is shown to be most sensitive to mercury emissions speciation uncertainty related to the burning of waste materials and electrical power generation. (C) 1998 Published by Elsevier Science B.V. C1 NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. DynTel, Res Triangle Pk, NC 27709 USA. ABB Power T&D Co Inc, Raleigh, NC 27606 USA. RP Bullock, OR (reprint author), NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. EM bro@hpcc.epa.gov NR 27 TC 15 Z9 17 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD JUN 10 PY 1998 VL 213 IS 1-3 BP 1 EP 12 DI 10.1016/S0048-9697(98)00066-7 PG 12 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZU102 UT WOS:000074162000001 ER PT J AU Leitner, A Rogers, CT Price, JC Rudman, DA Herman, DR AF Leitner, A Rogers, CT Price, JC Rudman, DA Herman, DR TI Pulsed laser deposition of superconducting Nb-doped strontium titanate thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID SRTIO3; SR1-XLAXTIO3 AB We report on the growth of superconducting Nb-doped SrTiO3 thin films on LaAlO3 substrates by pulsed laser deposition. We find optimum Nb doping and high mobility for growth near 870 degrees C and chamber pressures below 3 x 10(-4) Pa (2 x :10(-6) Ton). The transport properties were measured from 300 K to 150 mK. The most highly doped samples display metallic behavior, and are superconducting below 350 mK, with transition temperatures similar to those of bulk single crystals. (C) 1998 American Institute of Physics. [S0003-6951 (98)03323-3]. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Div 814 03, Boulder, CO 80303 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. RP Leitner, A (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NR 21 TC 53 Z9 53 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 8 PY 1998 VL 72 IS 23 BP 3065 EP 3067 DI 10.1063/1.121542 PG 3 WC Physics, Applied SC Physics GA 108PD UT WOS:000075273900047 ER PT J AU Uberna, R Khalil, M Williams, RM Papanikolas, JM Leone, SR AF Uberna, R Khalil, M Williams, RM Papanikolas, JM Leone, SR TI Phase and amplitude control in the formation and detection of rotational wave packets in the E-1 Sigma(+)(g) state of Li-2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENERGY-PHOTOELECTRON-SPECTRUM; DOUBLE-RESONANCE SPECTROSCOPY; SUB-DOPPLER SPECTROSCOPY; FEMTOSECOND LASER-PULSE; TIME-RESOLVED DYNAMICS; PUMP-PROBE EXPERIMENTS; RYDBERG STATES; COHERENT CONTROL; REAL-TIME; DIATOMIC-MOLECULES AB Femtosecond laser pulse amplitude/phase masking techniques are employed to control the formation and detection of rotational wave packets in the electronic E (1)Sigma(g)(+) state of lithium dimer. The wave packets are prepared by coherent excitation of rovibronic E (1)Sigma(g)(+) a ( VE,JE) states of Li-2 from a single intermediate state, A (1)Sigma(u)(+) (nu(A) = 11, J(A) = 28), and probed by time-resolved photoionization. In the detection step, the wave packet is projected onto the X (2)Sigma(g)(+) state of Li-2(+). New resonance structure in the X (2)Sigma(u)(+) ionic state continuum is obtained by measuring the wave packet signal modulation amplitude as a function of the frequencies removed from the spectrally dispersed probe pulse by insertion of a wire mask in a single-grating pulse shaper. A split glass phase mask inserted into the pulse shaper is used to produce step function changes in the spectral phase of the pulse. The phase relation among the wave packet states is varied by changing the relative phases of spectral components in the pump pulse and is monitored by measuring the changes in the phase of the rotational wave packet recurrences using an unmodified probe pulse. By altering the relative phases among the wave packet components, the spatial distribution of the initial wave packet probability density is varied, resulting in phase-dependent "alignment" of the probability density in angular space. Phase changes in the signal recurrences are also observed when a phase modified pulse is used in the wave packet detection step after wave packet preparation with an unmodified pulse. The formation and detection of the wave packets is discussed in terms of quantum interference between different excitation routes. The relative phase factors encoded in a single optical pulse (pump dr probe) are transferred into the interference term of the measured signal through the molecule-photon interaction. (C) 1998 American Institute of Physics. [S0021-9606(98)00222-0]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Biochem & Chem, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Uberna, R (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 69 TC 37 Z9 39 U1 2 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 1998 VL 108 IS 22 BP 9259 EP 9274 DI 10.1063/1.476381 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FT UT WOS:000075256000012 ER PT J AU Orzel, C Bergeson, SD Kulin, S Rolston, SL AF Orzel, C Bergeson, SD Kulin, S Rolston, SL TI Time-resolved studies of ultracold ionizing collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID METASTABLE XENON; ATOMS; STATE AB Using 40 ns laser pulses, we probe the real-time dynamics of ultracold ionizing collisions in metastable xenon. We time resolve both shielding and enhancement effects, and observe the production of Xe-2(+) molecular ions through associative ionization. We estimate the rate of molecule formation in excited-state collisions, and directly measure the role of both flux enhancement and excited state survival in the collisional enhancement process. Conceptually simple theoretical models are used to predict the dynamics of the collisional shielding. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Chem Phys Program, College Pk, MD 20742 USA. RP Orzel, C (reprint author), Natl Inst Stand & Technol, PHY A167, Gaithersburg, MD 20899 USA. RI rolston, steven/L-5175-2013; Bergeson, Scott/L-8959-2013 OI rolston, steven/0000-0003-1671-4190; Bergeson, Scott/0000-0002-3124-9226 NR 15 TC 20 Z9 20 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 8 PY 1998 VL 80 IS 23 BP 5093 EP 5096 DI 10.1103/PhysRevLett.80.5093 PG 4 WC Physics, Multidisciplinary SC Physics GA ZR769 UT WOS:000074011900017 ER PT J AU Hu, XZ Lawn, BR AF Hu, XZ Lawn, BR TI A simple indentation stress-strain relation for contacts with spheres on bilayer structures SO THIN SOLID FILMS LA English DT Article DE stress-strain relation; spheres; bilayer structures ID CERAMIC COATINGS; PLASTIC-DEFORMATION; DAMAGE ACCUMULATION; HERTZIAN CONTACTS; THIN-FILMS; FRACTURE; FATIGUE AB A simple formulation for the indentation stress-strain behavior of bilayers in contacts with hard spheres is proposed. The formulation is based on empirical power-law stress-strain relations for each of the individual constituent bulk materials, acid thence for the bilayer coating/substrate composite. For the constituent materials, two regions of response are considered: at low loads, an elastic region, with linear stress-strain response (exponent = 1); at high loads, an elastic-plastic region, with nonlinear stress-strain response (exponent < 1). The material responses in each of these two regions are characterized by effective moduli. For the composite bilayer, the transition in load-bearing capacity from coating to substrate with increasing load is represented by a three-parameter Weibull asymptotic function of ratio contact radius to coating thickness. This function conveniently defines the geometrical aspects of the contact response separately from the material properties. The power-law formulation is tested, and the Weibull parameters calibrated, against FEM-generated and experimental indentation stress-strain data for selected coating/substrate systems with widely different interlayer elastic-plastic mismatch. The formulation allows a priori predictions of the composite bilayer indentation stress-strain curves from control data on the constituent materials. Conversely, measurements of indentation stress-strain responses on given bilayers may be used to evaluate otherwise undeterminable elastic-plastic properties of coatings on well-characterized substrates. (C) 1998 Elsevier Science S.A. All rights reserved. C1 Univ Western Australia, Dept Mech & Mat Engn, Nedlands, WA 6907, Australia. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Univ Western Australia, Dept Mech & Mat Engn, Nedlands, WA 6907, Australia. RI Hu, Xiaozhi /H-4353-2011 NR 31 TC 50 Z9 50 U1 3 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUN 8 PY 1998 VL 322 IS 1-2 BP 225 EP 232 DI 10.1016/S0040-6090(97)00919-X PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA ZZ595 UT WOS:000074745900035 ER PT J AU Irvine, DJ Mayes, AM Satija, SK Barker, JG Sofia-Allgor, SJ Griffith, LG AF Irvine, DJ Mayes, AM Satija, SK Barker, JG Sofia-Allgor, SJ Griffith, LG TI Comparison of tethered star and linear poly(ethylene oxide) for control of biomaterials surface properties SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE protein adsorption; grafted PEG; reflectivity; star polymers; end-functional polymers ID GRAFTED POLYMER LAYERS; POLYETHYLENE OXIDE; POOR SOLVENT; NEUTRON REFLECTOMETRY; SULFONYL CHLORIDES; CELL-ADHESION; X-RAY; BRUSHES; CHAINS; IMMOBILIZATION AB Four different poly(ethylene oxide) [PEO] molecules were compared as grafted polymer layers for biomaterials' substrates: two linear polymers and two star polymers. Conditions maximizing surface coverage for each molecule were employed with the aim of inhibiting protein adsorption and increasing the density of end groups. Neutron reflectivities of the grafted layers immersed in deuterium oxide (heavy water) were measured and used to calculate volume fraction profiles of the polymer as a function of distance from the surface. These density profiles were combined with protein adsorption data on the grafted layers to compare with recent theoretical and experimental studies of protein resistance by PEO at surfaces. We found that the grafting density is maximized by coupling the linear PEO from a K2SO4 salt buffer, which is a poor solvent for PEO. However, the grafting density of star PEO was maximized when no K2SO4 was used and the stars were dissolved near the overlap concentration. Concentration profiles obtained from the reflectivity data show that the hydrated polymers swell to similar to 10 times the dried layer thickness and exhibit a low density (maximum volume fractions < 0.4 PEO) throughout the layer. The PEO surfaces obtained with both the star and linear polymers resisted adsorption of cytochrome-c and albumin except for a small amount of cytochrome-c adsorption on the short, many-armed star polymer surface. A hypothesis of adsorption on the star polymer layer is presented and criteria for controlling receptor-mediated cell-substrate interactions by ligand-modified chain ends are discussed. (C) 1998 John Wiley & Sons, Inc. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. MIT, Dept Chem Engn, Cambridge, MA 02139 USA. RP Mayes, AM (reprint author), MIT, Dept Mat Sci & Engn, 13-5066,77 Massachusetts Ave, Cambridge, MA 02139 USA. EM amayes@monosparc.mit.edu NR 61 TC 83 Z9 83 U1 1 U2 18 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD JUN 5 PY 1998 VL 40 IS 3 BP 498 EP 509 DI 10.1002/(SICI)1097-4636(19980605)40:3<498::AID-JBM21>3.0.CO;2-E PG 12 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA ZJ364 UT WOS:000073207100021 PM 9570083 ER PT J AU Chakrabarti, N Sathyamurthy, N Gadzuk, JW AF Chakrabarti, N Sathyamurthy, N Gadzuk, JW TI Photoinduced desorption of molecules from metal surfaces using femtosecond pulses: A model dynamical study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article; Proceedings Paper CT 3rd Femtochemistry Conference (Femtochemistry 97) CY AUG 31-SEP 04, 1997 CL LUND, SWEDEN ID ELECTRON MEDIATED PHOTODESORPTION; STIMULATED DESORPTION; LASER-DESORPTION; NO; PT(001); PT(111); STATE; NO/PT(111); CO AB The influence of a femtosecond laser pulse on an adsorbate molecule-metal surface system is investigated by considering a time-dependent coupling between the ground-and excited-state potential energy curves using the time-dependent quantum mechanical wave packet approach. It is shown that the probability of desorption is strongly dependent on the duration of the coupling and the image-charge attraction and that it increases with increase in vibrational excitation of the metal-adsorbate bond. C1 Indian Inst Technol, Dept Chem, Kanpur 208016, Uttar Pradesh, India. NIST, Gaithersburg, MD 20899 USA. RP Gadzuk, JW (reprint author), Indian Inst Technol, Dept Chem, Kanpur 208016, Uttar Pradesh, India. NR 39 TC 13 Z9 13 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 4 PY 1998 VL 102 IS 23 BP 4154 EP 4157 DI 10.1021/jp980043q PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZU017 UT WOS:000074152900015 ER PT J AU Dlugokencky, EJ Masarie, KA Lang, PM Tans, PP AF Dlugokencky, EJ Masarie, KA Lang, PM Tans, PP TI Continuing decline in the growth rate of the atmospheric methane burden SO NATURE LA English DT Article ID NORTHERN-HEMISPHERE; DRAMATIC DECREASE; CARBON-DIOXIDE; CH4; CO; ACCUMULATION AB The global atmospheric methane burden has more than doubled since pre-industrial times(1,2), and this increase is responsible for about 20% of the estimated change in direct radiative forcing due to anthropogenic greenhouse-gas emissions, Research into future climate change and the development of remedial environmental policies therefore require a reliable assessment of the long-term growth rate in the atmospheric methane load, Measurements have revealed that although the global atmospheric methane burden continues to increase(2) with significant interannual variability(3,4), the overall rate of increase has slowed(2,5), Here we present an analysis of methane measurements from a global air sampling network that suggests that, assuming constant OH concentration, global annual methane emissions have remained nearly constant during the period 1984-96, and that the decreasing growth rate in atmospheric methane reflects the approach to a steady state on a timescale comparable to methane's atmospheric lifetime. If the global methane sources and OH concentration continue to remain constant, we expect average methane mixing ratios to increase slowly from today's 1,730 nmol mol(-1) to similar to 1,800 nmol mol(-1), with little change in the contribution of methane to the greenhouse effect. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Dlugokencky, EJ (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. NR 21 TC 261 Z9 285 U1 4 U2 28 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD JUN 4 PY 1998 VL 393 IS 6684 BP 447 EP 450 DI 10.1038/30934 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZR842 UT WOS:000074020000038 ER PT J AU Wenthold, PG Squires, RR Lineberger, WC AF Wenthold, PG Squires, RR Lineberger, WC TI Ultraviolet photoelectron spectroscopy of the o-, m-, and p-benzyne negative ions. Electron affinities and singlet-triplet splittings for o-, m-, and p-benzyne SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAS-PHASE; ATOMIC OXYGEN; THERMOCHEMISTRY; SPECTRUM; ENERGY; HEAT; META; GENERATION; CHEMISTRY; ENEDIYNE AB The 351 nm photoelectron spectra of the negative ions of o-, m-, and p-benzyne (1,2-, 1,3-, and 1,4-dehydrobenzene, respectively) and their perdeuterated isotopomers have been obtained. The o-benzyne ions were generated by the reaction of benzene and benzene-d(6) with O-, while the m-and p-benzyne ions were prepared by the gas-phase reaction between the corresponding 3- and 4-(trimethylsilyl)phenyl anions and molecular fluorine, Fz. The photoelectron spectra of the benzyne anions each contain two features, corresponding to formation of the singlet and triplet states of the biradicals. The electron affinities of o- and p-benzyne are found to be 0.564 +/- 0.007 and 1.265 +/- 0.008 eV, respectively, while the electron affinities of deuterated o- and p-benzyne are found to be 8 and 5 meV lower, respectively. The electron affinity of m-benzyne could not be determined from the photoelectron spectrum because the origin peak could not be assigned unequivocally. For o- and p-benzyne, the singlet-tripiet energy splittings can be obtained directly from the photoelectron spectrum, with values of 37.5 +/- 0.3 and 3.8 +/- 0.5 kcal/mol, respectively, obtained for the h(4) species and 37.6 +/- 0.3 and 3.9 +/- 0.5 kcal/mol, respectively, obtained for the fully deuterated molecules. Using a previously reported value for the electron affinity of m-benzyne, the singlet-triplet splitting for this molecule is found to be 21.0 +/- 0.3 kcal/mol. Vibrational frequencies are reported for the deuterated and nondeuterated forms of all three biradicals and for the corresponding negative ions. Using the measured electron affinities and previously reported heats of formation of o-, m-, and p-benzyne, the gas-phase acidities of the ortho, meta, and para positions of phenyl radical are calculated to be 377.4 +/- 3.4, 386.8 +/- 3.2, and 393.1 +/- 3.0 kcal/mol, respectively, and the C-H bond energies at the ortho, meta, and para positions of phenyl anion are found to be 89.3 +/- 3.3, 98.7 +/- 3.1,and 105.0 +/- 2.9 kcal/mol, respectively. The heats of formation of the singlet and triplet states of the benzynes are found to be in excellent agreement with the predictions derived from simple valence promotion energy models. C1 Texas Tech Univ, Dept Chem & Biochem, Lubbock, TX 79409 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Wenthold, PG (reprint author), Texas Tech Univ, Dept Chem & Biochem, Lubbock, TX 79409 USA. NR 71 TC 218 Z9 218 U1 3 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JUN 3 PY 1998 VL 120 IS 21 BP 5279 EP 5290 DI 10.1021/ja9803355 PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA ZT015 UT WOS:000074039100018 ER PT J AU Koneripalli, N Levicky, R Bates, FS Matsen, MW Satija, SK Ankner, J Kaiser, H AF Koneripalli, N Levicky, R Bates, FS Matsen, MW Satija, SK Ankner, J Kaiser, H TI Ordering in blends of diblock copolymers SO MACROMOLECULES LA English DT Article ID BLOCK-COPOLYMERS; PHASE-BEHAVIOR; NEUTRON REFLECTIVITY; FORMING COPOLYMERS; MIXTURES; HOMOPOLYMER; INTERFACES; 2-BLOCK AB The morphology of binary blends of poly(styrene)-poly(2-vinylpyridine) (PS-PVP) diblock copolymers of the type (A-B)(alpha) + (A-B)(beta) was examined in a thin-film geometry using neutron reflection (NR), transmission electron microscopy (TEM), and self-consistent field (SCF) calculations. Blends of symmetric diblock copolymers (f(A,alpha)approximate to f(A,beta) approximate to x 0.5) revealed a localization of the lower molecular weight diblock copolymer and stretching of the higher molecular weight diblock copolymer near the AB interface that is qualitatively consistent with the data of a prior study by Mayes and co-workers. Blends of asymmetric diblock copolymers of the type f(A.alpha)< 0.5 and f(A,beta)< 0.5 having similar molecular weights (N-alpha approximate to N-beta) and with similar to 50% overall composition of a chemically similar block in the blend, [f(A)] approximate to 0.5, revealed molecular-level mixing of the two components and the formation of a single-phase morphology. A lamellar morphology was formed even when the individual components exhibit a nonlamellar morphology in the pure melt state. In general, the morphological characteristics are well anticipated by SCF calculations. After accounting for fluctuations at the interface, spatial distributions of the individual components in the blend obtained by SCF calculations were in close agreement with the NR data. For diblock copolymers near the order-disorder transition, a chi value higher than the bulk was necessary to fit the experimental data, suggesting an enhancement of ordering in the thin films near the transition due to the presence of the surfaces. C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. Univ Reading, Ctr Polymer Sci, Reading RG6 6AF, Berks, England. NIST, Div Reactor Radiat, Gaithersburg, MD 20899 USA. Univ Missouri, Res Reactor, Columbia, MO 65211 USA. RP Koneripalli, N (reprint author), 3M Co, Corp Res, Sci Res Lab, 3M Ctr, 201-2N-19, St Paul, MN 55144 USA. OI Ankner, John/0000-0002-6737-5718; Bates, Frank/0000-0003-3977-1278 NR 30 TC 47 Z9 48 U1 2 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 2 PY 1998 VL 31 IS 11 BP 3498 EP 3508 DI 10.1021/ma971229a PG 11 WC Polymer Science SC Polymer Science GA ZR874 UT WOS:000074023400016 ER PT J AU Levicky, R Koneripalli, N Tirrell, M Satija, SK AF Levicky, R Koneripalli, N Tirrell, M Satija, SK TI Concentration profiles in densely tethered polymer brushes SO MACROMOLECULES LA English DT Article ID MONTE-CARLO SIMULATION; DENSITY PROFILE; DYNAMICS; CHAINS; LAYERS; THETA C1 Univ Minnesota, Dept Chem Engn & Mat Sci, Minneapolis, MN 55455 USA. NIST, Ctr Neurtron Res, Gaithersburg, MD 20899 USA. RP Tirrell, M (reprint author), Univ Minnesota, Dept Chem Engn & Mat Sci, 421 Washington Ave SE, Minneapolis, MN 55455 USA. NR 22 TC 31 Z9 31 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 2 PY 1998 VL 31 IS 11 BP 3731 EP 3734 DI 10.1021/ma9717653 PG 4 WC Polymer Science SC Polymer Science GA ZR874 UT WOS:000074023400045 ER PT J AU Phinney, KW Sander, LC Wise, SA AF Phinney, KW Sander, LC Wise, SA TI Coupled achiral/chiral column techniques in subcritical fluid chromatography for the separation of chiral and nonchiral compounds SO ANALYTICAL CHEMISTRY LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; STATIONARY PHASE; HUMAN-PLASMA; BIOLOGICAL SAMPLES; SODIUM BENZOATE; PACKED-COLUMNS; ENANTIOMERS; BENZODIAZEPINES; URINE; METABOLITES AB A multicolumn approach was developed to address the limited achiral selectivity of chiral stationary phases. Groups of structurally related compounds, including P-blockers and 1,4-benzodiazepines, were separated using coupled achiral/chiral stationary phases under subcritical fluid conditions. The achiral selectivity of amino and cyano stationary phases was used to modify the resolution of compounds on a Chiralcel OD chiral stationary phase by combining the achiral and chiral columns in series. In the case of the benzodiazepines, separation of achiral compounds was performed concurrently with the enantioseparation of chiral molecules. The separation of components of a multidrug cough and cold medication was also demonstrated on a cyano column coupled with a Chiralpak AD chiral stationary phase. The use of modified carbon dioxide eluents eliminated the mobile phase incompatibility problems associated with column coupling in liquid chromatography and incorporated the high efficiency of sub-and supercritical fluid chromatography. C1 Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Phinney, KW (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 40 TC 42 Z9 43 U1 1 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUN 1 PY 1998 VL 70 IS 11 BP 2331 EP 2335 DI 10.1021/ac971060z PG 5 WC Chemistry, Analytical SC Chemistry GA ZR483 UT WOS:000073981600025 PM 9624904 ER PT J AU Migdall, A Datla, R Sergienko, A Orszak, JS Shih, YH AF Migdall, A Datla, R Sergienko, A Orszak, JS Shih, YH TI Measuring absolute infrared spectral radiance with correlated visible photons: technique verification and measurement uncertainty SO APPLIED OPTICS LA English DT Article ID EFFICIENCY; CALIBRATION AB An experimental system in which correlated photons for radiometric measurements were used has been set up at the National Institute of Standards and Technology. We use visible-FR pairs of correlated photons produced by means of optical parametric downconversion to measure the radiance of a high-temperature IR source at 3.415 and 4.772 mu m in an intrinsically absolute manner (i.e., without requiring any externally calibrated radiometric standard). To our knowledge, this is the only radiometric method with which one measures radiance directly, instead of using radiant power and aperture geometry measurements to deduce radiance indirectly. This technique has an additional unusual characteristic: It allows absolute radiometric measurements of IR radiation to be made with high-quality visible detectors. We compare measurements made with this technique with radiance measurements made with conventional means tied to existing radiometric standards. These comparisons show an average agreement to within similar to 3% between the two methods. The results demonstrate an accuracy consistent with the estimated uncertainty of the current measurements. This is the first time to our knowledge that this method has been used to provide absolute radiance measurements of a source that has been calibrated conventionally, revealing unexpected systematic effects and allowing estimates of the ultimate accuracy of this method. In addition, these measurements are further into the IR than any previous measurements of this process and have produced the highest thermally stimulated downconversion signal yet seen. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21228 USA. RP Migdall, A (reprint author), NIST, Opt Technol Div, 221-B208, Gaithersburg, MD 20899 USA. NR 20 TC 49 Z9 51 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 1 PY 1998 VL 37 IS 16 BP 3455 EP 3463 DI 10.1364/AO.37.003455 PG 9 WC Optics SC Optics GA ZQ398 UT WOS:000073857200013 PM 18273309 ER PT J AU Nunnallee, EP Prentice, EF Jonasson, BF Patten, W AF Nunnallee, EP Prentice, EF Jonasson, BF Patten, W TI Evaluation of a flat-plate PIT tag interrogation system at Bonneville Dam SO AQUACULTURAL ENGINEERING LA English DT Article DE flat-plate; PIT tag; passive integrated transponder; interrogation; Columbia River; salmon; radio frequency identification; RFID AB In the spring of 1996 and 1997, a prototype 400 kHz flat-plate (pass-by) passive integrated transponder tag interrogation (PIT tag) system was installed at the terminus of the downstream migrant (DSM) channel of the Bonneville Dam First Powerhouse, located on the Columbia River. The system was designed to interrogate previously PIT tagged juvenile salmonids migrating down the Columbia River without interfering with the traditional subsampling of fish passing through the facility. In addition, the design enables fish of virtually any size, and debris, to pass over the system's antennas without the port restrictions imposed by traditional pass-through PIT tag interrogation systems. We describe the fish facility in addition to the fiat-plate system and its operation. The system tag reading efficiency was evaluated during 1996 and 1997 using a direct method based on the release of known numbers of tagged test fish and an indirect statistical procedure based on tagged run-at-large fish. The results showed that PIT tag reading efficiency during both years using the direct method averaged 97%, while that using the statistical procedure averaged 99% for the dual multiplexed antenna array. During the 1996 and 1997 field seasons 4371 and 14733 fish, respectively, were recorded. Daily system functionality was monitored using stick tests (i.e., the passing of PIT tagged sticks across the antenna array). (C) 1998 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Patten Engn, Longmont, CO 80503 USA. RP Prentice, EF (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 8 TC 18 Z9 19 U1 1 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0144-8609 J9 AQUACULT ENG JI Aquac. Eng. PD JUN PY 1998 VL 17 IS 4 BP 261 EP 272 DI 10.1016/S0144-8609(98)00016-8 PG 12 WC Agricultural Engineering; Fisheries SC Agriculture; Fisheries GA ZY045 UT WOS:000074581100004 ER PT J AU Satoh, S Higgs, DA Dosanjh, BS Hardy, RW Eales, JG Deacon, G AF Satoh, S. Higgs, D. A. Dosanjh, B. S. Hardy, R. W. Eales, J. Geoffery Deacon, G. TI Effect of extrusion processing on the nutritive value of canola meal for chinook salmon (Oncorhynchus tshawytscha) in seawater SO AQUACULTURE NUTRITION LA English DT Article DE alternative protein source; canola meal; chinook salmon; extrusion process AB This study was conducted to evaluate three canola protein products as partial replacements of steam-dried whole herring meal (HM) in a practical diet for juvenile chinook salmon in seawater. Groups of 30-40 g chinook salmon held in 9.5-12 degrees C seawater on a natural photoperiod were fed one of seven equivalent protein (390 g kg(-1)) and isoenergetic (20 MJ gross energy kg(-1)) diets to satiation. Each of three test protein sources, namely, commercial canola meal (CM), low-temperature extruded CM (90 degrees C; LT), and high-temperature extruded CM (150 degrees C; HT) comprised about 120 and 240 g kg(-1) of dietary protein by replacement of 15 and 30%, respectively, of the HM protein in the control diet. Chinook salmon growth and feed intake were markedly depressed by replacing HM protein with a high level of CM, but these responses were not lowered by replacement with LT and HT. The phytic acid content in commercial canola meal was reduced by about 10 and 30% from the original level by extrusion cooking at low (90 degrees C) and high (150 degrees C) temperature, respectively. Therefore, the diets containing HT still had significant amounts of phytic acid. Terminal whole-body zinc contents were inversely related to the dietary levels of the different canola protein products. Thyroid function was altered by CM but this effect was offset by heat treatment. The results suggest that extrusion cooking of CM improves its nutritive value for chinook salmon in seawater. Indeed, it was found that HT could comprise 240 g kg(-1) of the dietary protein without adversely affecting performance. C1 [Satoh, S.] Tokyo Univ Fisheries, Dept Aquat Biosci, Minato Ku, Tokyo 108, Japan. [Higgs, D. A.; Dosanjh, B. S.] Fisheries & Oceans Canada, W Vancouver Lab, Dept Fisheries & Oceans, W Vancouver, BC V7V 1N6, Canada. [Hardy, R. W.] NOAA, Natl Marine Fisheries Serv, Dept Commerce, Seattle, WA 98115 USA. [Eales, J. Geoffery] Univ Manitoba, Dept Zool, Winnipeg, MB R3T 2N2, Canada. [Deacon, G.] Moore Clark Canada Inc, Vancouver, BC, Canada. RP Satoh, S (reprint author), Tokyo Univ Fisheries, Dept Aquat Biosci, Minato Ku, Tokyo 108, Japan. EM ssatoh@toyto-v-fish.ac.jp FU Ministry of Education, Japan FX We express our gratitude to Moore-Clark (Canada) Inc. who kindly extruded canola meal for our experiment. S. Satoh was supported in Canada by a grant from the Ministry of Education, Japan for overseas research by a young scientist. NR 25 TC 26 Z9 27 U1 0 U2 4 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1353-5773 J9 AQUACULT NUTR JI Aquac. Nutr. PD JUN PY 1998 VL 4 IS 2 BP 115 EP 122 DI 10.1046/j.1365-2095.1998.00056.x PG 8 WC Fisheries SC Fisheries GA V27FM UT WOS:000208599100006 ER PT J AU Fardal, MA Giroux, ML Shull, JM AF Fardal, MA Giroux, ML Shull, JM TI The high-redshift He II Gunn-Peterson effect: Implications and future prospects SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies, evolution; intergalactic medium; quasars, absorption lines ID LYMAN-ALPHA FOREST; ABSORPTION-LINE SYSTEMS; INTERGALACTIC MEDIUM; HELIUM ABSORPTION; LIMIT ABSORPTION; HIGH-RESOLUTION; BARYON DENSITY; IONIZED HELIUM; CLOUDS; QUASARS AB Absorption due to He II Ly alpha has now been detected at low resolution in the spectra of four quasars between redshifts z = 2.74 and z = 3.29. We assess these observations, giving particular attention to the radiative transfer of the ionizing background radiation, cloud diffuse emission and ionization physics, and statistical fluctuations. We use high-resolution observations of H I absorption toward quasars to derive an improved model for the opacity of the intergalactic medium (IGM) from the distribution of absorbing clouds in column density and redshift. We use these models to calculate the H I and He II photoionization history, the ratio eta = He II/H I in both optically thin and self-shielded clouds, and the average line-blanketing contribution of the clouds to He II absorption. The derived ionization rate, Gamma(HI) = (1-3) x 10(-12) s(-1) (z = 2-4), is consistent with the ionizing background intensity inferred from the "proximity effect," but it remains larger than that inferred by N-body hydrodynamic simulations of the Ly alpha absorber distribution. The He II observations are consistent with line blanketing from clouds having N(HI) greater-than-or-equal-to 10(12) cm(-2), although a contribution from a more diffuse IGM would help to explain the observed opacity. We compute the expected He II optical depth, tau(HeII)(z), and examine the implications of the sizable fluctuations that arise from variations in the cloud numbers and ionizing radiation field. We assess how He II absorption constrains the intensity and spectrum of the ionizing radiation and the fractional contributions of the dominant sources (quasars and starburst galaxies). Finally, we demonstrate how high-resolution ultraviolet observations can distinguish between absorption from the diffuse IGM and the Ly alpha forest clouds and determine the source of the ionizing background. C1 Univ Colorado, Ctr Astrophys & Space Astron, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fardal, MA (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, Dept Astrophys & Planetary Sci, Campus Box 389, Boulder, CO 80309 USA. NR 87 TC 123 Z9 123 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1998 VL 115 IS 6 BP 2206 EP 2230 DI 10.1086/300359 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZT599 UT WOS:000074104000003 ER PT J AU Smith, SB Reuter, GW Yau, MK AF Smith, SB Reuter, GW Yau, MK TI The episodic occurrence of hail in central Alberta and the highveld of South Africa SO ATMOSPHERE-OCEAN LA English DT Article ID SEVERE CONVECTIVE OUTBREAKS; PRECIPITATION; HAILSTORMS; EVENTS AB The frequency and duration of hail day episodes were analyzed based on 29 summers of hail data from central Alberta, Canada and 19 summers of data from the Highveld South Africa. A hail episode consists of one or more consecutive days with at least one hail report. A severe hail episode is defined as an episode that has at least one day of maximum hail size greater than or equal to 33 mm for Alberta, (greater than or equal to 31 mm for the Highveld). Severe and non-severe hail episodes are found to occur, on average, 6.6 and 11.2 times in Alberta, respectively, with mean durations of 4.2 and 2.1 days. In the Highveld severe and nonsevere hail episodes occur, on average, 2.8 and 21.9 times per six-month summer and have mean durations of 4.9 and 2.5 days. C1 Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. NOAA, Natl Weather Serv, Techniques Dev Lab, Off Syst Dev, Silver Spring, MD 20910 USA. McGill Univ, Dept Atmospher & Ocean Sci, Montreal, PQ, Canada. RP Reuter, GW (reprint author), Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. NR 16 TC 10 Z9 10 U1 0 U2 0 PU CANADIAN METEOROLOGICAL OCEANOGRAPHIC SOC PI OTTAWA PA 150 LOUIS PASTEUR PVT., STE 112, MCDONALD BUILDING, OTTAWA, ONTARIO K1N 6N5, CANADA SN 0705-5900 J9 ATMOS OCEAN JI Atmos.-Ocean PD JUN PY 1998 VL 36 IS 2 BP 169 EP 178 PG 10 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 123JQ UT WOS:000076122400004 ER PT J AU Feingold, G Walko, RL Stevens, B Cotton, WR AF Feingold, G Walko, RL Stevens, B Cotton, WR TI Simulations of marine stratocumulus using a new microphysical parameterization scheme SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT 12th International Conference on Clouds and Precipitation CY AUG 19-23, 1996 CL ZURICH, SWITZERLAND DE marine stratocumulus; microphysical scheme; simulation ID LARGE-EDDY SIMULATION; ASTEX LAGRANGIAN EXPERIMENTS; BOUNDARY-LAYER DYNAMICS; MODEL; DISTRIBUTIONS; CONDENSATION; COLLECTION; CLOUDINESS; DRIZZLE; FLUXES AB A new microphysical scheme that uses lognormal basis functions to represent cloud and drizzle drop spectra is presented. The scheme is incorporated in a two-dimensional (2-D) eddy-resolving model and applied to the simulation of a stratocumulus cloud deck based on a sounding from the Atlantic Stratocumulus Transition Experiment. Firstly, the philosophy behind the design of the scheme is discussed with emphasis on special problems that arise when simulating stratocumulus clouds. These include (but are not limited to) simulation of collection at low liquid water contents (a few tenths of g m(-3)), and the importance of correctly simulating drop sedimentation in weakly convective clouds. The scheme is then applied to two cases; one exhibiting weak precipitation (< 1 mm d(-1) at the surface) and the other, a more strongly precipitating case (1-3 mm d(-1) at the surface). Results show that the scheme captures the main features of a precipitating stratocumulus system when compared with the same model using a detailed bin microphysical scheme. The new scheme uses less than a fourth of the time required by the bin microphysical model and thus enables one to perform 2-D and 3-D simulations of the cloudy boundary layer over much larger domains, or much longer timescales than was previously possible. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NOAA, Environm Technol Lab, Cooperat Inst Res Atmosphere, Boulder, CO 80303 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Feingold, G (reprint author), NOAA, Environm Technol Lab, Cooperat Inst Res Atmosphere, 325 Broadway, Boulder, CO 80303 USA. EM gfeingold@etl.noaa.gov RI Stevens, Bjorn/A-1757-2013; Feingold, Graham/B-6152-2009 OI Stevens, Bjorn/0000-0003-3795-0475; NR 34 TC 73 Z9 75 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0169-8095 EI 1873-2895 J9 ATMOS RES JI Atmos. Res. PD JUN PY 1998 VL 48 SI SI BP 505 EP 528 DI 10.1016/S0169-8095(98)00058-1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY528 UT WOS:000074631000034 ER PT J AU Stevens, B Cotton, WR Feingold, G AF Stevens, B Cotton, WR Feingold, G TI A critique of one- and two-dimensional models of boundary layer clouds with a binned representations of drop microphysics SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT 12th International Conference on Clouds and Precipitation CY AUG 19-23, 1996 CL ZURICH, SWITZERLAND DE cloud-drop; bin-microphysical models; energy cascade ID STRATOCUMULUS CLOUDS; CONDENSATION NUCLEI; TURBULENCE AB A variety of models of boundary layer turbulence are increasingly being coupled to binned representation of cloud-drop spectra for the purpose of studying cloudy boundary layers and aerosol-cloud-drop interactions. A critique of one dimensional models shows that extant methods of coupling bin-microphysical models to the turbulence model omit important terms involving covariances of perturbation quantities. Errors incurred from the omission of these terms are significant: cloud-drop activation is not properly represented, and the initial stages of precipitation growth may be retarded in horizontally inhomogeneous boundary layers. if the promise of one-dimensional models is ever to be realized, some means of accurately representing these terms must be developed. Because large-scale models often have grid-spacings much larger than typical cloud-eddy-scale circulations, attempts to couple them to more detailed microphysical representations will also suffer from the problems discussed in the context of one-dimensional models. This should provide added motivation for improving the representation of microphysical processes on the sub-grid scale. An analysis of two-dimensional eddy-resolving models closed on the basis of energy inertial range arguments illustrates that the lack of an energy cascade in two dimensions results in increasingly vigorous circulations as the model's grid-mesh is refined. Two-dimensional model simulations can display significant variability to vanishingly small differences in the initial conditions, and drizzle rates vary by as much as 30% when total water concentrations are increased by only 1%. Such sensitivities make it difficult to constrain the models given the degree of uncertainty that characterizes measurements of state variables in clouds. Despite some inconsistencies in the formulation of their closure terms, two-dimensional models are at least able to qualitatively represent the interaction of the large-eddies and microphysical processes in boundary layer flows. For this reason they appear to be useful, not as surrogates for reality, but rather as a means for further refining hypotheses about the physical system thereby increasing the chances that such hypotheses can be tested observationally. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Ctr Atmospher Res, Adv Study Program, Boulder, CO 80304 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Environm Technol Lab, CIRA, Boulder, CO USA. RP Stevens, B (reprint author), Natl Ctr Atmospher Res, Adv Study Program, Boulder, CO 80304 USA. EM bstevens@ucar.edu RI Stevens, Bjorn/A-1757-2013; Feingold, Graham/B-6152-2009 OI Stevens, Bjorn/0000-0003-3795-0475; NR 26 TC 31 Z9 32 U1 1 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUN PY 1998 VL 48 SI SI BP 529 EP 553 DI 10.1016/S0169-8095(98)00059-3 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY528 UT WOS:000074631000035 ER PT J AU Song, QY Leighton, HG AF Song, QY Leighton, HG TI A parameterization of sulphate production in convective clouds for use in large-scale models SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT 12th International Conference on Clouds and Precipitation CY AUG 19-23, 1996 CL ZURICH, SWITZERLAND DE parameterization; sulphate production; convective clouds ID 3-DIMENSIONAL NUMERICAL-MODEL; PRECIPITATION CHEMISTRY; SIMULATION; RETENTION; DYNAMICS; CLIMATE; ICE AB A parameterization that describes in-cloud oxidation of S(IV) by hydrogen peroxide and ozone that is based on the reaction rate equations and basic cloud characteristics, has been developed for use in large-scale models. This parameterization is an explicit function of the concentration of ambient chemical species and some gross cloud parameters. Comparisons of the parameterization scheme with a well-established three-dimensional cloud chemistry model, and also with the cloud chemistry module of a regional model have been used to formulate and test this parameterization scheme. Results show that the parameterization agrees with the 3-D chemistry model very well and that the parameterization holds considerable potential for application in large-scale models. (C) 1998 Elsevier Science B.V. All rights reserved. C1 McGill Univ, Dept Atmospher & Ocean Sci, Montreal, PQ H3A 2K6, Canada. RP Song, QY (reprint author), US EPA, NOAA, UCAR Visiting Scientist Program, Natl Exposure Res Lab,Atmospher Sci Modeling Div, Mail Drop 80, Res Triangle Pk, NC 27711 USA. NR 28 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUN PY 1998 VL 48 SI SI BP 555 EP 572 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY528 UT WOS:000074631000036 ER PT J AU Olsson, PQ Harrington, JY Feingold, G Cotton, WR Kreidenweis, SM AF Olsson, PQ Harrington, JY Feingold, G Cotton, WR Kreidenweis, SM TI Exploratory cloud-resolving simulations of boundary-layer arctic stratus clouds Part I: Warm-season clouds SO ATMOSPHERIC RESEARCH LA English DT Article; Proceedings Paper CT 12th International Conference on Clouds and Precipitation CY AUG 19-23, 1996 CL ZURICH, SWITZERLAND DE arctic stratus clouds; boundary layer dynamics; climate arctic; radiation; cloud microphysics ID RADIATIVE PROPERTIES; CONDENSATION NUCLEI; WATER CLOUDS; PARAMETERIZATION; MICROPHYSICS; CLIMATE; MODELS; STRATOCUMULUS; TURBULENCE; AEROSOLS AB Two-dimensional simulations of arctic stratus clouds (ASC) were conducted using a sophisticated cloud-resolving model with explicit microphysics and a two-stream radiative transfer model. The effects of varying cloud condensation nuclei (CCN) concentrations upon the subsequent cloud and its microphysical, radiative and dynamical structure were studied. In this study CCN concentrations were varied within the ranges found in warm-season arctic boundary layers (ABLs) to produce non-drizzling and weakly drizzling stratus decks. Experiments that included all model physics, no-drizzle, and no shortwave radiation were conducted to elucidate the effects of microphysics and radiation on the simulated stratus. Both simulations that did and that did not include the effects of drizzle showed that the higher CCN concentrations produced a cloud with larger reflectivity and absorptivity, but also produced eddies that were weaker than with lower CCN concentrations. Simulations that included the effects of drizzle showed a similar response to changes in CCN concentrations. Simulations with no drizzle produced more vigorous eddies than their drizzling counterparts because cooling due to evaporation below cloud tends to stabilize the ABL. The simulations without the effects of short-wave radiation produced very vigorous eddies that penetrated more deeply into the ABL. In this case, the simulation with higher CCN concentrations produced the most vigorous eddies. This resulted from a subtle interplay of microphysics, radiation, and dynamics. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Harrington, JY (reprint author), Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. RI Feingold, Graham/B-6152-2009; Kreidenweis, Sonia/E-5993-2011 OI Kreidenweis, Sonia/0000-0002-2561-2914 NR 43 TC 4 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0169-8095 EI 1873-2895 J9 ATMOS RES JI Atmos. Res. PD JUN PY 1998 VL 48 SI SI BP 573 EP 597 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZY528 UT WOS:000074631000037 ER PT J AU Bohnsack, JA AF Bohnsack, JA TI Application of marine reserves to reef fisheries management SO AUSTRALIAN JOURNAL OF ECOLOGY LA English DT Article; Proceedings Paper CT Joint United-States/Australia Workshop on Recruitment and Population Dynamics of Coral-Reef Fishes (Reefish 95) CY DEC 11, 1995 CL KURANDA, AUSTRALIA SP Australian Dept Ind, Sci & Tourisms Bilateral Sci & Technol Collaborat Program, USA Natl Sci Fdn Int Programs DE biodiversity; conservation; coral reefs; ecosystem; no-take; refuge ID PROTECTED AREAS; NEW-ZEALAND; FISH; POPULATIONS; SIZE; CONSERVATION; COMMUNITY; SELECTION; HISTORY; ISLAND AB Establishing permanent 'no-take' marine reserves, areas where fishing and all other extractive activities are prohibited, is an attractive but under-utilized tool for fisheries management. Marine reserves could potentially deal with many fishery problems that are not effectively addressed by other traditional management measures; they also offer numerous social, economic, and scientific benefits not directly related to fisheries. Limited but gr owing research has shown beneficial biological and economic effects of marine reserves on fisheries. More research is needed, especially at larger scales, to determine the ideal marine reserve size, number and location necessary to optimize fisheries productivity and resource conservation. Sufficient evidence is available to justify the expanded use of marine reserves in an adaptive approach to fisheries management. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. RP Bohnsack, JA (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. NR 74 TC 155 Z9 161 U1 2 U2 37 PU BLACKWELL SCIENCE PI CARLTON PA 54 UNIVERSITY ST, P O BOX 378, CARLTON, VICTORIA 3053, AUSTRALIA SN 0307-692X J9 AUST J ECOL JI Aust. J. Ecol. PD JUN PY 1998 VL 23 IS 3 BP 298 EP 304 DI 10.1111/j.1442-9993.1998.tb00734.x PG 7 WC Ecology SC Environmental Sciences & Ecology GA ZU238 UT WOS:000074176200016 ER PT J AU Demartini, EE AF Demartini, EE TI How might recruitment research on coral-reef fishes help manage tropical reef fisheries? SO AUSTRALIAN JOURNAL OF ECOLOGY LA English DT Article; Proceedings Paper CT Joint United-States/Australia Workshop on Recruitment and Population Dynamics of Coral-Reef Fishes (Reefish 95) CY DEC 11, 1995 CL KURANDA, AUSTRALIA SP Australian Dept Ind, Sci & Tourisms Bilateral Sci & Technol Collaborat Program, USA Natl Sci Fdn Int Programs DE ecology; exploitation; life history; movements; size ID GREAT-BARRIER-REEF; LUTJANUS-ADETII CASTELNAU; POPULATION-STRUCTURE; DAMSELFISHES POMACENTRIDAE; PLECTROPOMUS-LEOPARDUS; QUINQUELINEATUS BLOCH; MORTALITY-RATES; AGE VALIDATION; LARVAL SIZE; GROWTH AB 'Ecologic' reef fishes (basic research subjects) and 'Economic' reef fishes (exploited by humans) share fundamental early life-history attributes of small, widely dispersed planktonic eggs, larvae, and (for some species in both groups) pelagic juveniles. These attributes predispose the open populations of species in both groups to limitation resulting from environmentally induced fluctuations in recruitment from planktonic/pelagic to benthic stages. Rates of movement within and among reefs, one of several postrecruitment processes likely to be subject to density-dependent regulation, may differ between Ecologics (mostly small-bodied) and Economics (generally larger-bodied). This is because of differences between species in the two groups in size-related differences in the home ranges of individuals. Existing data, however, neither support the notion that natural growth and mortality rates basically differ between the adults of Ecological and Economic species, nor that the generally larger home ranges of larger-bodied adult Economics are more subject to density-dependent control. Further, the small-bodied young-of-year juveniles of both groups on average probably have similar growth and mortality rates and small individual home ranges that are equivalently affected by density dependence. In conclusion I argue that, because of fundamental similarities in the sizes and durations of planktonic propagules and spawning periodicities, certain Ecologics and Economics may comprise a single recruitment guild. Coefficients of growth and mortality for postsettlement Ecologics also may resemble, and be applied as preliminary proxies for, analogous coefficients for Economic species. The efficacy of management strategies such as harvest refugia may differ for Ecological and Economic species, however, depending on whether the refugia are used to counter growth or recruitment overfishing. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, 2570 Dole St, Honolulu, HI 96822 USA. NR 57 TC 6 Z9 6 U1 0 U2 6 PU BLACKWELL PUBLISHING ASIA PI CARLTON PA 54 UNIVERSITY ST, P O BOX 378, CARLTON, VICTORIA 3053, AUSTRALIA SN 0307-692X J9 AUST J ECOL JI Aust. J. Ecol. PD JUN PY 1998 VL 23 IS 3 BP 305 EP 310 DI 10.1111/j.1442-9993.1998.tb00735.x PG 6 WC Ecology SC Environmental Sciences & Ecology GA ZU238 UT WOS:000074176200017 ER PT J AU Dempsey, CL Howard, KW Maddox, RA Phillips, DH AF Dempsey, CL Howard, KW Maddox, RA Phillips, DH TI Developing advanced weather technologies for the power industry SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The National Severe Storms Laboratory, the Salt River Project (SRP), and the Electric Power Research Institute have been involved in a multiyear tailored collaboration (TC) research project. The project was jointly supported by all three agencies and had the goal of exploring potential benefits that the power industry could realize by incorporating new weather information, resulting from the National Weather Service's modernization program, into their operational decision-making process. The SRP, which is one of the nation's largest public utilities and located in the greater Phoenix metropolitan area, served as a test bed for a variety of experimental techniques that could easily be emulated in the future. Activities during this TC were focused upon weather-related problems experienced during the summer monsoon months when thunderstorms can threaten or impact SRP's operations on a daily basis. Weather information and special forecasts were introduced to and shared with several of SRP's operational divisions through the course of this TC; their degree of utilization and subsequent improvements to SRP's operational efficiency are summarized in this paper. C1 Salt River Project, Water Resource Operat, Phoenix, AZ 85072 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Dempsey, CL (reprint author), Salt River Project, Water Resource Operat, Mail Stn PAB203,POB 52025, Phoenix, AZ 85072 USA. NR 7 TC 10 Z9 10 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1998 VL 79 IS 6 BP 1019 EP 1035 DI 10.1175/1520-0477(1998)079<1019:DAWTFT>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZX060 UT WOS:000074475800001 ER PT J AU Locatelli, JD Stoelinga, MT Hobbs, PV Johnson, J AF Locatelli, JD Stoelinga, MT Hobbs, PV Johnson, J TI Structure and evolution of an undular bore on the high plains and its effects on migrating birds SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID MORNING GLORY; LOWER ATMOSPHERE; NONLINEAR-WAVES; GRAVITY CURRENT; UNITED-STATES; WIND PROFILER; SQUALL-LINE; COLD FRONTS; GUST FRONT; LEE TROUGH AB On 18 September 1992 a series of thunderstorms in Nebraska and eastern Colorado, which formed south of a synoptic-scale cold front and north of a Rocky Mountain lee trough, produced a cold outflow gust front that moved southeastward into Kansas, southeastern Colorado, and Oklahoma around sunset. When this cold outflow reached the vicinity of the lee trough, an undular bore developed on a nocturnally produced stable layer and moved through the range of the Dodge City WSR-88D Doppler radar. The radar data revealed that the undular bore, in the leading portion of a region of northwesterly winds about 45 km wide by 4 km high directly abutting the cold outflow, developed five undulations over the course of 3 h. Contrary to laboratory tank experiments, observations indicated that the solitary waves that composed the bore probably did not form from the enveloping of the head of the cold air outflow by the stable layer and the breaking off of the head of the cold air outflow. The synoptic-scale cold front subsequently intruded on the surface layer of air produced by the cold outflow, but there was no evidence for the formation of another bore. Profiler winds, in the region affected by the cold air outflow and the undular bore, contained signals from nocturnally, southward-migrating birds (most likely waterfowl) that took off in nonfavorable southerly winds and remained aloft for several hours longer than usual, thereby staying ahead of the turbulence associated with the undular bore. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Natl Weather Serv, Dodge City, KS USA. RP Hobbs, PV (reprint author), Univ Washington, Dept Atmospher Sci, Box 3516490, Seattle, WA 98195 USA. NR 52 TC 22 Z9 22 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1998 VL 79 IS 6 BP 1043 EP 1060 DI 10.1175/1520-0477(1998)079<1043:SAEOAU>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZX060 UT WOS:000074475800003 ER PT J AU Skalski, JR Smith, SG Iwamoto, RN Williams, JG Hoffmann, A AF Skalski, JR Smith, SG Iwamoto, RN Williams, JG Hoffmann, A TI Use of passive integrated transponder tags to estimate survival of migrant juvenile salmonids in the Snake and Columbia rivers SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article AB Single-release and modified single-release statistical models were evaluated as means to generate reliable survival estimates from release-recapture studies of migrant salmonid smelts in the Snake and Columbia rivers of the northwestern United States. Monte Carlo simulation studies were used to assess robustness of estimation methods to violations of model assumptions. To field test model assumptions, passive integrated transponder tagged chinook salmon (Oncorhynchus tshawytscha) smelts were released on seven consecutive days in 1993 above Lower Granite Dam on the Snake River. These releases were used to estimate sampling variability of survival estimates for comparison with model-based variance estimates and to assess mixing of detected and nondetected individuals. Field results satisfied model assumptions. The average survival estimate from point of release to the tailrace of Lower Granite Dam (31 km) was 0.902 +/- 0.004 (mean +/- SE). From the tailrace of Lower Granite Dam to the tailrace of Little Goose Dam (60 km) the average survival estimate was 0.859 +/- 0.013. C1 Univ Washington, Sch Fisheries, Seattle, WA 98101 USA. NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Natori, Miyagi 98112, Japan. RP Skalski, JR (reprint author), Univ Washington, Sch Fisheries, 1325 4th Ave,Suite 1820, Seattle, WA 98101 USA. OI Skalski, John/0000-0002-7070-2505 NR 20 TC 84 Z9 86 U1 0 U2 8 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD JUN PY 1998 VL 55 IS 6 BP 1484 EP 1493 DI 10.1139/cjfas-55-6-1484 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 117WJ UT WOS:000075805400018 ER PT J AU Thomas, JJ Jennings, HM Allen, AJ AF Thomas, JJ Jennings, HM Allen, AJ TI The surface area of cement paste as measured by neutron scattering: Evidence for two C-S-H morphologies SO CEMENT AND CONCRETE RESEARCH LA English DT Article ID HYDRATING CEMENT AB Small-angle neutron scattering was used to measure the effect of water-to-cement ratio (w/c) and cement batch variation on the surface area of ordinary Portland cement (OPC) paste after hydration for 28 days at room temperature, and to measure the development of surface area over the first 3 days of hydration at 30 degrees C. The 28-day surface area was found to increase with w/c ratio in proportion to the volume of original water-filled space available for reaction product to form. The surface areas of different batches of type I OPC were quite similar, while that of a type II OPC was some 15% lower. Early surface area development at 30 degrees C followed the heat evolution for the first 24 h of hydration and then leveled off, suggesting that further heat evolution was associated with reaction product, which added little to the surface area. These results support the theory that two different morphologies of the calcium-silicate-hydrate gel reaction product form during cement hydration. (C) 1998 Elsevier Science Ltd. C1 Northwestern Univ, Dept Civil Engn, Evanston, IL 60208 USA. Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Jennings, HM (reprint author), Northwestern Univ, Dept Civil Engn, Evanston, IL 60208 USA. RI Jennings, Hamlin/B-7006-2009; Thomas, Jeffrey/B-7103-2009; OI Thomas, Jeffrey/0000-0003-2897-2023 NR 12 TC 71 Z9 76 U1 1 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD JUN PY 1998 VL 28 IS 6 BP 897 EP 905 DI 10.1016/S0008-8846(98)00049-0 PG 9 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA ZY875 UT WOS:000074670800014 ER PT J AU Bentz, DP Garboczi, EJ Lagergren, ES AF Bentz, DP Garboczi, EJ Lagergren, ES TI Multi-scale microstructural modeling of concrete diffusivity: Identification of significant variables SO CEMENT CONCRETE AND AGGREGATES LA English DT Article DE concrete diffusivity; durability; experimental design; interfacial transition zone; microstructure; modeling; performance prediction ID DC ELECTRICAL-CONDUCTIVITY; INTERFACIAL ZONE; CEMENT PASTE; SILICA FUME; PERCOLATION; HYDRATION; MORTARS; SIMULATION; IONS AB The ability to predict the expected chloride diffusivity of a concrete based on its mixture proportions and field-curing conditions would be of great benefit both in predicting service life of the concrete and in developing durability-based design codes. Here, a multi-scale microstructural computer model is applied to computing the chloride diffusivities of concretes with various mixture proportions and projected degrees of hydration. A fractional factorial experimental design has been implemented to study the effects in the model of seven major variables: water-to-cement (W/C) ratio, degree of hydration, aggregate volume fraction, coarse:aggregate particle size distribution, fine aggregate particle size distribution, interfacial transition zone thickness, and air content. Based on this experimental design, WIC ratio, degree of hydration, and aggregate volume fraction have been identified as the three major variables influencing concrete diffusivity in the model. Following identification of the significant variables, a response surface design has I,een executed and least squares regression used to develop a simple equation; for predicting chloride ion diffusivity in concrete based on these three parameters. This simple equation essentially summarizes the complicated simulations involved in computing the model response, Finally, simulations have been conducted to examine the extent of the surface layer in cast-in-place concrete, where the local aggregate volume fraction near the surface is less than that to be found in the bulk of the concrete. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NIST, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Bentz, DP (reprint author), NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 43 TC 49 Z9 49 U1 0 U2 16 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0149-6123 J9 CEMENT CONCRETE AGGR JI Cem. Concr. Aggreg. PD JUN PY 1998 VL 20 IS 1 BP 129 EP 139 PG 11 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 187QZ UT WOS:000079799400001 ER PT J AU Frost, MJ Kato, S Bierbaum, VM Leone, SR AF Frost, MJ Kato, S Bierbaum, VM Leone, SR TI Reactions of N-2(+)(upsilon) with CO and NO at thermal energy SO CHEMICAL PHYSICS LA English DT Article ID VIBRATIONALLY EXCITED N-2+; LASER-INDUCED FLUORESCENCE; ION-MOLECULE REACTIONS; GAS-PHASE ION; CHARGE-TRANSFER; NEUTRAL COLLISIONS; RATE COEFFICIENTS; DEACTIVATION; 300-K; N+ AB A selected ion flow tube (SIFT), laser induced fluorescence (LIF) technique is used for vibrational state specific measurements of the total removal rate constants and vibrational relaxation for N-2(+)(v) reactions with CO and NO. The removal rate constants for N-2(+)(v = 0 and 2) in collisions with CO are 0.76 (+/- 0.10) and 1.8 (+/- 0.3) x 10(-10) cm(3) molecule(-1) s(-1), respectively, obtained by comparison with the rate constant for the N-2(+) (v = 1) + Ar charge transfer reaction. The increased reactivity with vibrational excitation arises both from vibrational deactivation and enhanced charge transfer. For N-2(+)(v = 0 and 2) in collisions with NO, the ions are removed with rate constants of 3.8 (+/- 0.3) and 6.3 (+/- 1.0) x 10(-10) cm(3) molecule(-1) s(-1), respectively. The increased reactivity with vibrational excitation arises primarily from vibrational deactivation. The rate constants and vibrational relaxation mechanisms of the N-2(+)(v) + CO and N-2(+)(v) + NO reactions are compared with earlier results from our laboratory for the N-2(+)(v) + O-2 reaction. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. EM srl@jila.colorado.edu NR 30 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 1 PY 1998 VL 231 IS 2-3 BP 145 EP 153 DI 10.1016/S0301-0104(97)00348-0 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZT945 UT WOS:000074144200004 ER PT J AU Gierczak, T Burkholder, JB Bauerle, S Ravishankara, AR AF Gierczak, T Burkholder, JB Bauerle, S Ravishankara, AR TI Photochemistry of acetone under tropospheric conditions SO CHEMICAL PHYSICS LA English DT Article ID ABSORPTION CROSS-SECTIONS; QUANTUM YIELDS; SPECTRUM; GAS; PHOTODISSOCIATION; HYDROCARBONS; DEPENDENCE; PHOTOLYSIS; KINETICS; KETONES AB The absorption cross sections of acetone were measured between 215 and 350 nm over the temperature range of 235 to 298 K using a diode array spectrometer. The quantum yield for the photodissociation of acetone was measured as a function of pressure at nine discrete wavelengths between 248 and 337 mn. At wavelengths longer than 270 nm, the quantum yields were found to decrease with increasing pressure in accordance with the Stern-Volmer mechanism. The zero pressure quantum yield was found to increase as the wavelength decreased and reached a value of unity near 290 nm. The quantum yields at 308 nm were found to be nearly independent of temperature between 298 and 195 K. These results were used to calculate an expression for the variation of the acetone photodissociation quantum yield with pressure and wavelength. The calculated atmospheric photolysis lifetime of acetone shows the photolysis to be the main loss process for acetone in the upper troposphere, while reaction with the OH radicals dominates its loss rate near the Earth's surface. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Ravishankara, AR (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 30 TC 121 Z9 123 U1 2 U2 26 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 1 PY 1998 VL 231 IS 2-3 BP 229 EP 244 DI 10.1016/S0301-0104(98)00006-8 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZT945 UT WOS:000074144200012 ER PT J AU Gossiaux, DC Landrum, PF Fisher, SW AF Gossiaux, DC Landrum, PF Fisher, SW TI The assimilation of contaminants from suspended sediment and algae by the zebra mussel, Dreissena polymorpha SO CHEMOSPHERE LA English DT Article ID ORGANIC-CHEMICALS; SAGINAW BAY; LAKE HURON; SIZE; ACCUMULATION; PARTICLES; DIPOREIA; SESTON; PALLAS; PCBS AB Since their invasion into the Great Lakes, zebra mussels, Dreissena polymorpha, have increased the water clarity in Lake St. Clair and Lake Erie due to their extensive particle filtration. Because these particles contain sorbed contaminants, the potential for contaminant accumulation from both suspended sediment and algae were examined. Sediment or algae were dosed with selected radiolabeled polycyclic aromatic hydrocarbon congeners and/or hexachlorobiphenyl (HCBP). Assimilation efficiencies were measured and depended on food quality. Zebra mussels, 17 +/- 2 mm long, assimilated 58.3 +/- 13.5 % of the pyrene and 44.7 +/- 5.8 % of the benzo(a)pyrene (BaP) from sediment particles with a particle clearance rate of 493 -897 ml/g tissue/h. However, assimilation efficiencies were 91.7 +/- 3.7 % for pyrene, 91.9 +/- 1.4 % for BaP, 96.6 +/- 1.4 % for chrysene, and 97.7 +/- 0.5 % for HCBP from suspended algae. Algal particle clearance rates for the mussels ranged from 47 -143 ml/g tissue/h. Thus, zebra mussels efficiently accumulated non-polar contaminants sorbed to algae, while a smaller fraction of the sediment-associated contaminant was bioavailable. Furthermore, the contaminants sorbed onto suspended sediment particles were quickly removed from the water and deposited as pseudofeces. The pseudofeces production was positively correlated with filtration rate and suspended particle concentrations. Published by Elsevier Science Ltd. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Ohio State Univ, Dept Entomol, Columbus, OH 43210 USA. RP Gossiaux, DC (reprint author), NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. NR 30 TC 44 Z9 44 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD JUN PY 1998 VL 36 IS 15 BP 3181 EP 3197 DI 10.1016/S0045-6535(98)00020-4 PG 17 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZP463 UT WOS:000073756000014 PM 9747518 ER PT J AU D'Andrea, F Tibaldi, S Blackburn, M Boer, G Deque, M Dix, MR Dugas, B Ferranti, L Iwasaki, T Kitoh, A Pope, V Randall, D Roeckner, E Straus, D Stern, W Van den Dool, H Williamson, D AF D'Andrea, F Tibaldi, S Blackburn, M Boer, G Deque, M Dix, MR Dugas, B Ferranti, L Iwasaki, T Kitoh, A Pope, V Randall, D Roeckner, E Straus, D Stern, W Van den Dool, H Williamson, D TI Northern Hemisphere atmospheric blocking as simulated by 15 atmospheric general circulation models in the period 1979-1988 SO CLIMATE DYNAMICS LA English DT Article ID PREDICTABILITY; CLIMATOLOGY; VARIABILITY; ANOMALIES; FREQUENCY; ATLANTIC; PROJECT; IMPACT; WINTER AB As a part of the Atmospheric Model Intercomparison Project (AMIP), the behaviour of 15 general circulation models has been analysed in order to diagnose and compare the ability of the different models in simulating Northern Hemisphere midlatitude atmospheric blocking. In accordance with the established AMIP procedure, the 10-year model integrations were performed using prescribed, time-evolving monthly mean observed SSTs spanning the period January 1979-December 1988. Atmospheric observational data (ECMWF analyses) over the same period have been also used to verify the models results. The models involved in this comparison represent a wide spectrum of model complexity, with different horizontal and vertical resolution, numerical techniques and physical parametrizations, and exhibit large differences in blocking behaviour. Nevertheless, a few common features can be found, such as the general tendency to underestimate both blocking frequency and the average duration of blocks. The problem of the possible relationship between model blocking and model systematic errors has also been assessed, although without resorting to ad-hoc numerical experimentation it is impossible to relate with certainty particular model deficiencies in representing blocking to precise parts of the model formulation. C1 Univ Reading, Dept Meteorol, Reading RG6 2AH, Berks, England. Canadian Ctr Climate Res, Victoria, BC, Canada. Ctr Natl Rech Meteorol, Toulouse, France. Commonwealth Sci & Ind Res Org, Mordialloc, Vic, Australia. Rech Previs Numer, Dorval, PQ, Canada. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. Japan Meteorol Agcy, Numer Predict Div, Tokyo, Japan. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Hadley Ctr Climate Predict & Res, UK Meteorol Off, Bracknell, Berks, England. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Max Planck Inst Meteorol, Hamburg, Germany. Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. NOAA, Natl Weather Serv, Natl Meteorol Ctr, Washington, DC 20233 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Bologna, Dept Phys, Atmospher Dynam Grp, I-40126 Bologna, Italy. RP CNRS, Meteorol Dynam Lab, Paris, France. RI Dix, Martin/A-2334-2012; Randall, David/E-6113-2011 OI Dix, Martin/0000-0002-7534-0654; Randall, David/0000-0001-6935-4112 NR 39 TC 127 Z9 129 U1 1 U2 14 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0930-7575 EI 1432-0894 J9 CLIM DYNAM JI Clim. Dyn. PD JUN PY 1998 VL 14 IS 6 BP 385 EP 407 DI 10.1007/s003820050230 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZU249 UT WOS:000074177400001 ER PT J AU O'Connell, CD Juhasz, A Kuo, C Reeder, DJ Hoon, DSB AF O'Connell, CD Juhasz, A Kuo, C Reeder, DJ Hoon, DSB TI Detection of tyrosinase mRNA in melanoma by reverse transcription-PCR and electrochemiluminescence SO CLINICAL CHEMISTRY LA English DT Article ID POLYMERASE CHAIN-REACTION; MALIGNANT-MELANOMA; MESSENGER-RNA; RT-PCR; DNA-POLYMERASE; CELLS; QUANTITATION; SENSITIVITY; BLOOD; GENE AB Increased sensitivity and improved quantitation of analytical tests used in biotechnology and clinical chemistry are goals of many laboratories. We have used tyrosinase primers to specifically amplify by RT-PCR the tyrosinase mRNA expressed by the M12 melanoma cell Line in a background of mRNA from breast cancer cells. An electrochemiluminescence detection procedure was used as a readout system for this study. Biotinylated post-PCR cDNA samples were hybridized to a tris(2,2'-bipyridine)ruthenium(II) (TBR) chelate-labeled oligonucleotide probe, and the hybrid was subsequently captured by streptavidin-coated Dynabeads(R). When either the QPCR System 5000 or the Origen 1 Analyzer System were used, the luminescence emitted by the TBR-chelate of the captured specific post-PCR product was assessed. Tyrosinase-specific mRNA isolated from similar to 1-10 melanoma cells in a background of 10(7) cells could be detected. We improved the sensitivity and logistics of the assay through the use of rTth for reverse transcription and amplification Tyrosinase mRNA was detected in blood from 7 of 16 melanoma patients, whereas none of the 5 healthy donor bloods were positive (P = 0.01; Wilcoxon test). C1 NIST, Chem Sci & Technol Lab, Div Biotechnol, Gaithersburg, MD 20899 USA. John Wayne Canc Inst, Dept Mol Oncol, Santa Monica, CA 90404 USA. RP O'Connell, CD (reprint author), NIST, Chem Sci & Technol Lab, Div Biotechnol, Gaithersburg, MD 20899 USA. EM coc@nist.gov OI Hoon, Dave/0000-0003-1915-3683 FU NCI NIH HHS [CA 1038, CA 29605] NR 22 TC 42 Z9 43 U1 3 U2 5 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 USA SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD JUN PY 1998 VL 44 IS 6 BP 1161 EP 1169 PN 1 PG 9 WC Medical Laboratory Technology SC Medical Laboratory Technology GA ZR716 UT WOS:000074006600005 PM 9625038 ER PT J AU Gorti, SR Gupta, A Kim, GJ Sriram, RD Wong, A AF Gorti, SR Gupta, A Kim, GJ Sriram, RD Wong, A TI An object-oriented representation for product and design processes SO COMPUTER-AIDED DESIGN LA English DT Article DE design; knowledge-base; object-oriented model; design process; ontology; representation AB We report on the development of a knowledge representation model, which is based on the SHARED object model reported in Shared Workspaces for Computer-Aided Collaborative Engineering (Wong, A. and Sriram, D., Technical Report, IESL 93-06, Intelligent Engineering Systems Laboratory, Department of Civil Engineering, MIT, March, 1993) and Research in Engineering Design (Wong, A. and Sriram, D., SHARED: An Information Model for Cooperative Product Development, 1993, Fall, 21-39). Our current model is implemented as a layered scheme, that incorporates both an evolving artifact and its associated design process. To represent artifacts as they evolve, we define objects recursively without a pre-defined granularity on this recursive decomposition. This eliminates the need for translations between levels of abstraction in the design process. The SHARED model extends traditional OOP in three ways: (1) by allowing explicit relationship classes with inheritance hierarchies; (2) by permitting constraints to be associated with objects and relationships; and (3) by comparing 'similar' objects at three different levels (form, function and behavior). Five primitive objects define the design process: goal, plan, specification, decision and context. Goal objects achieve function, introduce constraints, introduce new artifacts or modify existing ones, and create subgoals. Plan objects order goals and link a product hierarchy to a process hierarchy. Specification objects define user inputs as constraints. Decision objects relate goals to user decisions and context objects describe the design context. Operators that are applied to design objects collectively form a representation of the design process for a given context. The representation is robust enough to effectively model four design paradigms [described in Journal of CAD (Gorti, S. and Sriram, R. D., Symbol to Form Mapping: a Framework for Conceptual Design, 1996, 28(11), 853-870)]: top-down decomposition, stepwise refinement, bottom-up composition and constraint propagation. To demonstrate this, we represent the designs of two TV remote controllers in the SHARED architecture. The example reveals that certain aspects of artifact knowledge are essentially context-independent and that this representation can be a foundation for robust knowledge-based systems in design. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. C1 NIST, Engn Design Technol Grp, Gaithersburg, MD 20899 USA. Schlumberger Austin Syst Ctr, Austin, TX 78726 USA. POSTECH, Dept Comp Sci, Pohang, South Korea. Indian Inst Technol, Dept Civil Engn, New Delhi, India. Schlumberger, GeoQuest, Houston, TX 77042 USA. RP Sriram, RD (reprint author), NIST, Engn Design Technol Grp, Gaithersburg, MD 20899 USA. EM sriram@cme.nist.gov NR 25 TC 95 Z9 112 U1 1 U2 15 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0010-4485 J9 COMPUT AIDED DESIGN JI Comput.-Aided Des. PD JUN PY 1998 VL 30 IS 7 BP 489 EP 501 DI 10.1016/S0010-4485(97)00087-0 PG 13 WC Computer Science, Software Engineering SC Computer Science GA ZX609 UT WOS:000074535400001 ER PT J AU Kia, OE Doermann, DS Rosenfeld, A Chellappa, R AF Kia, OE Doermann, DS Rosenfeld, A Chellappa, R TI Symbolic compression and processing of document images SO COMPUTER VISION AND IMAGE UNDERSTANDING LA English DT Article ID HUFFMAN; CODES AB In this paper, we describe a compression and representation scheme which exploits the component-level redundancy found within a document image. The approach identifies patterns which appear repeatedly, represents similar patterns with a single prototype, stores the location of pattern instances, and codes the residuals between the prototypes and the pattern instances. Using a novel encoding scheme, we provide a representation that facilitates scalable lossy compression and progressive transmission and supports document image analysis in the compressed domain. We motivate the approach, provide details of the encoding procedures, report compression results, and describe a class of document image understanding tasks that operate on the compressed representation. (C) 1998 Academic Press. C1 Univ Maryland, Lab Language & Media Proc, College Pk, MD 20742 USA. Univ Maryland, Ctr Automat Res, College Pk, MD 20742 USA. RP NIST, Gaithersburg, MD 20899 USA. EM omid.kia@nist.gov; doermann@cfar.umd.edu NR 54 TC 4 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1077-3142 EI 1090-235X J9 COMPUT VIS IMAGE UND JI Comput. Vis. Image Underst. PD JUN PY 1998 VL 70 IS 3 BP 335 EP 349 DI 10.1006/cviu.1998.0682 PG 15 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA ZR488 UT WOS:000073982300006 ER PT J AU Waples, RS AF Waples, RS TI Evolutionarily significant units, distinct population segments, and the endangered species act: Reply to Pennock and Dimmick SO CONSERVATION BIOLOGY LA English DT Editorial Material ID CONSERVATION C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, Seattle, WA 98112 USA. RP Waples, RS (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. RI Waples, Robin/K-1126-2016 NR 17 TC 51 Z9 52 U1 0 U2 16 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD JUN PY 1998 VL 12 IS 3 BP 718 EP 721 DI 10.1046/j.1523-1739.1998.97524.x PG 4 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA ZT948 UT WOS:000074144500029 ER PT J AU Porch, CE AF Porch, CE TI A numerical study of larval fish retention along the southeast Florida coast SO ECOLOGICAL MODELLING LA English DT Article DE recruitment; dispersal; transport; fish larvae; Florida ID CORAL-REEF FISHES; GREAT BARRIER-REEF; HAEMULON-FLAVOLINEATUM; NORTH-ATLANTIC; MEANDERING JET; RECRUITMENT; KEYS; TRANSPORT; POPULATION; DISPERSAL AB The possibility that the eggs and larvae of southeast Florida fishes can be retained by local hydrodynamic processes is examined using simple idealizations of the local currents, oceanic turbulence, Ekman drift, horizontal larval swimming and larval mortality. The simulated settling rates were greatly affected by the interaction between the hydrodynamics and the degree of spatial heterogeneity in the mortality fields. In the presence of an onshore Ekman drift, for example, settling rates tended to increase unless the mortality rate over the reef was much higher than elsewhere. Overall, the simulations suggest that the meanders, eddies and gyres associated with the Florida current front can retain between 0.07 and 41% of the larvae with planktonic life spans on the order of 1 month. However, only a recirculating gyre enabled large numbers of larvae to settle within a few kilometers of their birth place. Assuming the mortality rate near the reef is 20-90% per day, but lower offshore, between 0.1 and 7% of the larvae retained are likely to settle. This implies that southeast Florida reef fish populations should be able to replenish themselves without relying on upstream sources of recruitment, provided they exhibit normal fecundities. The simulations also suggest that natural levels of variation in the mortality held or local currents can both cause large fluctuations in recruitment. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. RP Porch, CE (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 75 Virginia Beach Dr, Miami, FL 33149 USA. EM clay.porch@noaa.gov RI 平山, 幸恵/G-9307-2012 NR 77 TC 30 Z9 30 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 EI 1872-7026 J9 ECOL MODEL JI Ecol. Model. PD JUN 1 PY 1998 VL 109 IS 1 BP 35 EP 59 DI 10.1016/S0304-3800(98)00005-2 PG 25 WC Ecology SC Environmental Sciences & Ecology GA ZU623 UT WOS:000074216600003 ER PT J AU Sae-Ma, B Meier, PG Landrum, PF AF Sae-Ma, B Meier, PG Landrum, PF TI Effect of extended storage time on the toxicity of sediment-associated cadmium on midge larvae (Chironomus tentans) SO ECOTOXICOLOGY LA English DT Article DE Chironomus tentans; sediment toxicity; sediment storage time; sediment-associated cadmium AB The effect of the duration of spiked sediment storage on cadmium toxicity was studied. Sediment samples were spiked with cadmium to obtain concentrations of 0.6, 16.0, 29.0 and 53.0 mu g Cd per g sediment (dry weight). The spiked sediment was then stored in sealed plastic containers at 4 degrees C in the dark. Sediment bioassays, using Chironomus tentans, were conducted immediately and at periodic intervals for up to 4 months. Though the levels of cadmium in the bulk sediment samples from different stored periods were not significantly different, different toxicity levels to C. tentans were observed. The toxicity was significantly different between subsequent storage times. There was a significant decrease in the bioaccumulation factor (BAF) values with extended storage times, indicating a reduction in the bioavailability of cadmium. This study suggests that the storage of spiked sediment used in sediment toxicity study can influence the results. C1 Univ Michigan, Dept Environm & Ind Hlth, Ann Arbor, MI 48109 USA. Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Sae-Ma, B (reprint author), 802 Fuller Rd 32, Ann Arbor, MI 48104 USA. NR 28 TC 2 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0963-9292 J9 ECOTOXICOLOGY JI Ecotoxicology PD JUN PY 1998 VL 7 IS 3 BP 133 EP 139 DI 10.1023/A:1014300209848 PG 7 WC Ecology; Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZN243 UT WOS:000073626200002 ER PT J AU Atha, DH AF Atha, DH TI Characterization of DNA standards by capillary electrophoresis SO ELECTROPHORESIS LA English DT Article DE DNA standards; capillary electrophoresis; ethidium bromide ID DOUBLE-STRANDED DNA; FRAGMENTS; SEQUENCE; SEPARATION; RESOLUTION; PLASMID AB We have used capillary electrophoresis to evaluate commercial DNA size standards and have found that it can provide an efficient assessment of size. However, the accuracy of the determination is adversely affected by anomalous migration times due to specific interactions of the DNA with the gel matrix as well as conformational differences in the DNA due to sequence heterogeneity. These anomalous migration times are strongly dependent on the choice of gel matrix. For example, the anomalous migration times that are observed in a 1 kilobase standard DNA ladder can be minimized using nongel hydroxyethylcellulose. In addition, the peak resolution can be increased and the anomalous migration can be reduced by the addition of the intercalating dye, ethidium bromide. However, in the case of the D1S80 allelic ladder, some of the DNA fragments possess nucleotide sequences which do not interact equivalently with the dye and produce irregular migration times. These measurements yield preliminary information useful in evaluating DNA size standards which may be used for a wide range of DNA diagnostic applications. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Atha, DH (reprint author), NIST, Div Biotechnol, Bld 222,Rm A-353, Gaithersburg, MD 20899 USA. NR 26 TC 5 Z9 5 U1 0 U2 3 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD JUN PY 1998 VL 19 IS 8-9 BP 1428 EP 1435 DI 10.1002/elps.1150190837 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZY715 UT WOS:000074652100037 PM 9694292 ER PT J AU Thiebaux, HJ AF Thiebaux, HJ TI A process-convolution approach to modelling temperatures in the North Atlantic Ocean - Discussion SO ENVIRONMENTAL AND ECOLOGICAL STATISTICS LA English DT Article C1 Environm Modeling Ctr, Camp Sprins, MD 20733 USA. RP Thiebaux, HJ (reprint author), Environm Modeling Ctr, 5200 Auth Rd, Camp Sprins, MD 20733 USA. NR 5 TC 0 Z9 0 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1352-8505 J9 ENVIRON ECOL STAT JI Environ. Ecol. Stat. PD JUN PY 1998 VL 5 IS 2 BP 191 EP 192 DI 10.1023/A:1009618922526 PG 2 WC Environmental Sciences; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Environmental Sciences & Ecology; Mathematics GA 127AU UT WOS:000076328200006 ER PT J AU Hyland, JL Snoots, TR Balthis, WL AF Hyland, JL Snoots, TR Balthis, WL TI Sediment quality of estuaries in the southeastern US SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article; Proceedings Paper CT 3rd Symposium on the Environmental Monitoring and Assessment Program CY APR 08-11, 1997 CL ALBANY, NEW YORK SP US EPA ID UNITED-STATES; MARINE AB A study was conducted to assess the condition of estuaries in the EMAP Carolinian Province (Cape Henry, VA - St. Lucie Inlet, FL). Synoptic measures of sediment contamination, toxicity, and macroinfaunal condition were made at 82 and 86 stations in 1994 and 1995, respectively, in accordance with a probabilistic sampling design. These data were used to estimate percentages of degraded vs. undegraded estuarine area from the perspective of sediment quality. Each year a sizable portion of the province (36% in 1994, 51% in 1995) showed some evidence of either degraded benthic assemblages, contaminated sediments in excess of bioeffect guidelines, or significant sediment toxicity (based on Ampelisca abdita and Microtox(R) assays). However, co-occurrences of a degraded benthos and adverse exposure conditions (sediment contamination and/or toxicity) were much less extensive - 17% of the province in 1994 and 25% in 1995. Each year only four sites, representing 5% of the province in 1994 and 8% in 1995, had degraded infauna accompanied by both sediment contamination and toxicity, suggesting that strong contaminant-induced effects on the benthos (based on such combined weight-of-evidence) were limited to a fairly small percentage of estuarine area province-wide. PCBs and pesticides (lindane, dieldrin, DDT and derivatives) were the most dominant contaminants over the two-year period. The broad-scale sampling design of EMAP was not intended to support detailed characterizations of potential pollutant impacts within individual estuaries. Thus, some estuaries classified as undegraded may include additional degraded portions outside the immediate vicinity of randomly sampled sites. Such localized impacts (not accounted for in the above estimates) were detected in this study at additional nonrandom supplemental sites near potential contaminant sources. C1 NOAA, Carolinian Prov Off, Charleston, SC 29422 USA. RP Hyland, JL (reprint author), NOAA, Carolinian Prov Off, 217 Fort Johnson Rd,POB 12559, Charleston, SC 29422 USA. NR 22 TC 14 Z9 14 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-6369 J9 ENVIRON MONIT ASSESS JI Environ. Monit. Assess. PD JUN PY 1998 VL 51 IS 1-2 BP 331 EP 343 DI 10.1023/A:1005959907969 PG 13 WC Environmental Sciences SC Environmental Sciences & Ecology GA ZK650 UT WOS:000073346600027 ER PT J AU Johnson, BT Long, ER AF Johnson, BT Long, ER TI Rapid toxicity assessment of sediments from estuarine ecosystems: A new tandem in vitro testing approach SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE sediment toxicity; genotoxicity; in vitro testing; estuarines; toxicity screening ID ASSAY; GENOTOXICITY; ACTIVATION; BIOASSAYS; MICROTOX; BACTERIA; MUTATOX; EMBRYO AB Microtox(R) and Mutatox(R) were used to evaluate the acute toxicity and genotoxicity, respectively, of organic sediment extracts from Pensacola Bay and St. Andrew Bay, two estuaries that cover about 273 and 127 km(2), respectively, along the Gulf coast of Florida, USA. The sensitivity and selectivity of these two bioluminescent toxicity assays were demonstrated in validation studies with over 50 pesticides, genotoxins, and industrial pollutants, both as single compounds and in complex mixtures. The 50% effective concentration (EC50) values of insecticides, petroleum products, and polychlorinated biphenyls determined by Microtox all tended to group around the mean EC50 value of 1.2 (0.8) mg/L. The polycyclic aromatic hydrocarbon sensitivity of Mutatox was in general similar to that reported in the Ames test. Surficial sediment samples were collected, extracted with dichloromethane, evaporated and concentrated under nitrogen, dissolved in dimethyl sulfoxide, assayed for acute toxicity and genotoxicity, and compared with reference sediments. Samples with low EC50 values, and determined to be genotoxic, were detected in Massalina Bayou, Watson Bayou, East Bay, and St. Andrew Bay-East in St. Andrew Bay as well as Bayou Grande, Bayou Chico, and Bayou Texar in Pensacola Bay. An overview of these data Lets analyzed by Spearman rank correlation showed a significant correlation between acute toxicity and genotoxicity (p < 0.05). Microtox and Mutatox in tandem was a sensitive, cost-effective, and rapid (<24 h) screening tool that identified troublesome areas of pollution and assessed the potential sediment toxicity of lipophilic contaminants in aquatic ecosystems. C1 US Geol Survey, Biol Resources Div, Envirom & Contaminants Res Ctr, Columbia, MO 65201 USA. NOAA, Coastal Monitoring & Bioeffects Assessment Div, Seattle, WA 98115 USA. RP Johnson, BT (reprint author), US Geol Survey, Biol Resources Div, Envirom & Contaminants Res Ctr, 4200 New Haven Rd, Columbia, MO 65201 USA. NR 42 TC 49 Z9 49 U1 2 U2 4 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUN PY 1998 VL 17 IS 6 BP 1099 EP 1106 DI 10.1897/1551-5028(1998)017<1099:RTAOSF>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZN878 UT WOS:000073692600016 ER PT J AU Karshenboim, S Jentschura, U Ivanov V Soff, G AF Karshenboim, S Jentschura, U Ivanov, V Soff, G TI Corrections to the wave function and the hyperfine structure in exotic atoms SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID PI(-) MESONS; HYDROGEN; PI(+) AB We present an analytical evaluation of radiative corrections in exotic atoms induced by the one-loop electronic vacuum polarization. We evaluate corrections to the energy levels, to the wave function (at the origin) and to the hyperfine structure. We treat all corrections analytically within a non-relativistic approximation. Agreement is found with a few available numerical results. The analytical treatment allows to determine the asymptotic forms of the corrections in the limit of a small atomic radius, which for the atomic systems considered corresponds to a large mass of the constituent particle as compared to the electron mass. The asymptotics can be verified using the effective charge approach. C1 DI Mendeleev Inst Metrol, St Petersburg 198005, Russia. Max Planck Inst Phys Komplexer Syst, D-01069 Dresden, Germany. Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Pulkovo Observ, St Petersburg 196140, Russia. RP Karshenboim, S (reprint author), DI Mendeleev Inst Metrol, St Petersburg 198005, Russia. EM sgk@onti.vniim.sbp.su; ulrich@theory.phy.tu-dresden.de; soff@physik.tu-dresden.de RI Ivanov, Vladimir/B-9957-2011; Karshenboim, Savely/C-1456-2011 NR 17 TC 17 Z9 17 U1 1 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD JUN PY 1998 VL 2 IS 3 BP 209 EP 215 DI 10.1007/s100530050133 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 107UV UT WOS:000075230100005 ER PT J AU Schmitten, RA AF Schmitten, RA TI An agenda for bycatch SO FISHERIES LA English DT Editorial Material C1 NMFS, Silver Spring, MD 20910 USA. RP Schmitten, RA (reprint author), NMFS, 1315 EW Highway,Room 14555, Silver Spring, MD 20910 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0363-2415 J9 FISHERIES JI Fisheries PD JUN PY 1998 VL 23 IS 6 BP 6 EP 6 PG 1 WC Fisheries SC Fisheries GA ZQ913 UT WOS:000073915600002 ER PT J AU Kendall, AW Duker, GJ AF Kendall, AW Duker, GJ TI The development of recruitment fisheries oceanography in the United States SO FISHERIES OCEANOGRAPHY LA English DT Review DE history; ICES; CalCOFI; Baird; Hjort; Sette; Walford ID LARVAL AB Recruitment fisheries oceanography studies the impact of the environment on the annual production of young to fished populations (finfish as well as invertebrates). Interannual variation in recruitment is the most important source of biological variability facing fisheries managers. Because most variation in recruitment occurs during early, mainly planktonic stages, recruitment fisheries oceanography usually integrates studies of plankton and physical oceanography. The concepts upon which these studies rest were first expressed in the late 1800s by Spencer Fullerton Baird, the first Commissioner of the US Commission of Fish and Fisheries. These concepts appear to have been independently developed by Johan Hjort and others in northern Europe in the early 1900s, and brought back to the United States through contacts between Hjort and Henry Bryant Bigelow, who passed the ideas to his students at Harvard University, including Lionel Albert Walford and Oscar Elton Sette. Although both Walford and Sette did their initial work in recruitment fisheries oceanography off the US east coast, as federal fisheries scientists, they were sent to California in response to the decline of the sardine fishery, where they incorporated the ideas of Hjort into the programme that has become the California Cooperative Oceanic Fisheries Investigations (CalCOFI). The original plan for CalCOFI research was to provide a test: of Hjort's ideas. Scientists working with CalCOFI implemented this plan and conducted subsequent research that had its roots in the ideas expressed by Baird. This research was in marked contrast to the fishery-yield orientation of most fisheries research that was being conducted at the time on the west coast of North America, under the dominating influence of William Francis Thomyson. In recent years, federal fisheries programmes have investigated recruitment processes of a number of other fish stocks, and considerable effort has been expended toward refining the conceptual framework beyond the hypotheses of Hjort. This paper expands on this history, making note of scientists who were particularly important in the evolution of this discipline. We conclude that although recruitment fisheries oceanography has become a well-established field of study, and many technological advances have been made, the recruitment process is still not well understood and fluctuations in year-class abundance remain a major source of uncertainty in managing marine fisheries. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Kendall, AW (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM kendall@afsc.noaa.gov NR 88 TC 24 Z9 24 U1 0 U2 4 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD JUN PY 1998 VL 7 IS 2 BP 69 EP 88 DI 10.1046/j.1365-2419.1998.00056.x PG 20 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 115ZA UT WOS:000075695200001 ER PT J AU Wyllie-Echeverria, T Wooster, WS AF Wyllie-Echeverria, T Wooster, WS TI Year to-year variations in Bering Sea ice cover and some consequences for fish distributions SO FISHERIES OCEANOGRAPHY LA English DT Article DE Aleutian Low Pressure System; Arctic cod; cold pool; decadal variability; sea ice; walleye pollock ID PACIFIC; CLIMATE; CIRCULATION; TEMPERATURE; VARIABILITY; EXTENT; SHELF AB The southernmost extension of winter ice cover varies interannually and on longer time scales, reflecting large-scale changes in driving forces, especially in the position and intensity of the winter Aleutian Low Pressure System. A conspicuous pattern is alternating warm and cool periods of several years' duration. These variations in sea ice cover are reflected in the character of a subsurface cold pool, formed as stratification isolates the deeper cold waters from surface exchanges. The cold pool is better developed and more extensive in summers that follow deep southward penetration of winter sea ice. Interannual and decadal-scale variations in the distributions of some fish stocks reflect those of ice and thermal conditions. In particular, the distribution of walleye pollock, Theragra chalcogramma, varies significantly with multiannual cool and warm years while Arctic cod, Boreogadus saida, is only present within the cold pool. The relation among climate variations, sea ice cover, subsurface thermal conditions, and fish distribution provides information on how climate affects marine ecosystems and may also have practical application in predicting fish distributions. C1 Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Inst Study Atmosphere & Oceans, Seattle, WA 98105 USA. Univ Washington, Sch Marine Affairs, Seattle, WA 98105 USA. RP Pacific Marine Environm Lab, Seattle, WA 98115 USA. EM tinawe@pmel.noaa.gov NR 42 TC 114 Z9 115 U1 0 U2 15 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1054-6006 EI 1365-2419 J9 FISH OCEANOGR JI Fish Oceanogr. PD JUN PY 1998 VL 7 IS 2 BP 159 EP 170 DI 10.1046/j.1365-2419.1998.00058.x PG 12 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 115ZA UT WOS:000075695200008 ER PT J AU Kiselev, SB AF Kiselev, SB TI Cubic crossover equation of state SO FLUID PHASE EQUILIBRIA LA English DT Article DE carbon dioxide; critical state; cubic equation of state; vapor-liquid equilibria; R32; R125; water ID GLOBAL THERMODYNAMIC BEHAVIOR; PENG-ROBINSON EQUATION; CRITICAL REGION; VAPOR-PRESSURES; FLUID MIXTURES; PENTAFLUOROETHANE R125; TEMPERATURE RELATION; CARBON-DIOXIDE; PVT PROPERTIES; DENSITY AB In this paper we develop a cubic crossover equation of state for pure fluids which incorporates the scaling laws asymptotically close to the critical point and is transformed into the original classical cubic equation of state far away from the critical point. We use the modified Patel-Teja (PT) cubic equation of state as a starting point. A comparison is made with experimental data for pure CO2, water, and refrigerants R32 and R125 in the one- and two-phase regions. We show that the crossover Patel-Teja equation of state yields a much better representation of the thermodynamic properties of pure fluids, especially in the critical region and for vapor-liquid equilibrium, than the original PT equation of state. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Kiselev, SB (reprint author), Russian Acad Sci, Inst Oil & Gas Res, Leninsky Prospect 63-2, Moscow 117917, Russia. NR 55 TC 118 Z9 121 U1 2 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD JUN PY 1998 VL 147 IS 1-2 BP 7 EP 23 DI 10.1016/S0378-3812(98)00222-2 PG 17 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 102YF UT WOS:000074953300002 ER PT J AU Strom, MS AF Strom, MS TI Phenotypic and genetic characterization of a non-hemolytic variant of Listeria monocytogenes from cold-smoked salmon SO FOOD MICROBIOLOGY LA English DT Article ID POLYMERASE CHAIN-REACTION; INTRACELLULAR GROWTH; STREPTOCOCCUS-PNEUMONIAE; FISHERY PRODUCTS; ESCHERICHIA-COLI; VIRULENCE GENES; PATHOGENESIS; EXPRESSION; TRANSFORMATION; PNEUMOLYSIN AB The identity of 11 strains of Listeria monocytogenes and L. innocua isolated from various processed seafood products was confirmed by the polymerase chain reaction (PCR). All species' identities determined by a combination of selective media, beta-hemolysis, and biochemical fermentation profiles were confirmed by PCR, with one exception. One strain (4-4), previously identified as L. innocua because of the lack of hemolysis on blood agar, was shown to be L. monocytogenes. In order to determine whether this isolate was a weakly hemolytic variant and thus potentially virulent, or whether it was truly unable to express listeriolysin (LLO), a number of phenotypic and genetic characterizations were performed. The strain was competent for expression of other L. monocytogenes Virulence factors and characteristics such as the phosphatidylinositol-specific phospholipase C and the ability to adhere to and invade Caco-2 and J774 cells, but could not grow intracellularly and was avirulent in mice. DNA sequencing of the LLO gene (hly) from strain 4-4 showed that the genetic lesion was a single base-pair deletion, resulting in a frame-shift and subsequent stop codon in the translated open reading frame. Such a mutation is unique from those seen in previously described naturally occurring non-hemolytic L. monocytogenes strains. (C) U.S. Government. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, US Dept Commerce,Utilizat Res Div, Seattle, WA 98112 USA. RP Strom, MS (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, US Dept Commerce,Utilizat Res Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 38 TC 7 Z9 7 U1 0 U2 5 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0740-0020 J9 FOOD MICROBIOL JI Food Microbiol. PD JUN PY 1998 VL 15 IS 3 BP 329 EP 337 DI 10.1006/fmic.1997.0171 PG 9 WC Biotechnology & Applied Microbiology; Food Science & Technology; Microbiology SC Biotechnology & Applied Microbiology; Food Science & Technology; Microbiology GA 101UF UT WOS:000074886000011 ER PT J AU Grant, WB Pierce, RB Oltmans, SJ Browell, EV AF Grant, WB Pierce, RB Oltmans, SJ Browell, EV TI Seasonal evolution of total and gravity wave induced laminae in ozonesonde data in the tropics and subtropics SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC OZONE; LOWER STRATOSPHERE; POLAR VORTEX; TRANSPORT AB ECC ozonesonde ozone and potential temperature profile data for several stations from 25.05 degrees S to 19.6 degrees N were processed to look for the type, seasonal behavior, and vertical distribution of the laminar structure in the troposphere and lower stratosphere. The fractions of ozone laminae associated with Rossby and gravity wave induced laminae were determined from correlations between ozone and potential temperature structure. Gravity-wave-induced laminae in the stratosphere were found to be associated with deep convection in the winter months and winds form the southwest in the summer months for the Hilo station, and orographic wave activity for the Pretoria station in September. Mo significant Rossby wave activity was found for these stations. Lower tropospheric laminae of mixed characteristics were found to be prevalent at the Hilo, related to transport from the northeast, and the continental tropical stations in the June-August period, which are associated with biomass burning. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Grant, WB (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, MS 401A, Hampton, VA 23681 USA. RI Pierce, Robert Bradley/F-5609-2010; Grant, William/B-8311-2009 OI Pierce, Robert Bradley/0000-0002-2767-1643; Grant, William/0000-0002-1439-3285 NR 30 TC 18 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1863 EP 1866 DI 10.1029/98GL01297 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800027 ER PT J AU Solomon, S Portmann, RW Garcia, RR Randel, W Wu, F Nagatani, R Gleason, J Thomason, L Poole, LR McCormick, MP AF Solomon, S Portmann, RW Garcia, RR Randel, W Wu, F Nagatani, R Gleason, J Thomason, L Poole, LR McCormick, MP TI Ozone depletion at mid-latitudes: Coupling of volcanic aerosols and temperature variability to anthropogenic chlorine SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HETEROGENEOUS CHEMISTRY; ERUPTION; PINATUBO; ACID AB Satellite observations of total ozone at 40-60 degrees N are presented from a variety of instruments over the time period 1979-1997. These reveal record low values in 1992-3 (after Pinatubo) followed by partial but incomplete recovery. The largest post-Pinatubo reductions and longer-term trends occur in spring, providing a critical test for chemical theories of ozone depletion. The observations are shown to be consistent with current understanding of the chemistry of ozone depletion when changes in reactive chlorine and stratospheric aerosol abundances are considered along with estimates of wave-driven fluctuations in stratospheric temperatures derived from global temperature analyses. Temperature fluctuations are shown to make significant contributions to model calculated northern mid-latitude ozone depletion due to heterogeneous chlorine activation on liquid sulfate aerosols at temperatures near 200-210K (depending upon water vapor pressure), particularly after major volcanic eruptions. Future mid-latitude ozone recovery will hence depend not only on chlorine recovery but also on temperature trends and/or variability, volcanic activity, and any trends in stratospheric sulfate aerosol. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Natl Ctr Environm Predict, Washington, DC 20233 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Aerosol Res Branch, Hampton, VA 23665 USA. Hampton Univ, Dept Phys, Hampton, VA 23665 USA. RP Solomon, S (reprint author), NOAA, Aeron Lab, 325 Broadway,R E AL8, Boulder, CO 80303 USA. RI Portmann, Robert/C-4903-2009; Gleason, James/E-1421-2012; Randel, William/K-3267-2016; OI Portmann, Robert/0000-0002-0279-6087; Randel, William/0000-0002-5999-7162; Thomason, Larry/0000-0002-1902-0840 NR 29 TC 70 Z9 70 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1871 EP 1874 DI 10.1029/98GL01293 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800029 ER PT J AU Flocke, F Atlas, E Madronich, S Schauffler, SM Aikin, K Margitan, JJ Bui, TP AF Flocke, F Atlas, E Madronich, S Schauffler, SM Aikin, K Margitan, JJ Bui, TP TI Observations of methyl nitrate in the lower stratosphere during STRAT: Implications for its gas phase production mechanisms SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PEROXYACETYL NITRATE; ION COMPOSITION; PHOTOCHEMISTRY EXPERIMENT; 2-DIMENSIONAL MODEL; ALKYL NITRATES; TEMPERATURE; RADICALS; PRESSURE AB Methyl nitrate has been measured for the first time in the lower stratosphere at altitudes to 20.5 km during the December 1996 NASA Stratospheric Tracers of Atmospheric Transport (STRAT) deployment. Whole air samples were taken on board the NASA ER2 aircraft and analyzed using gas chromatography/mass spectrometry. Methyl nitrate was present at measurable levels throughout the entire altitude range covered. Taking advantage of the rather simple chemistry in the lower stratosphere compared to the troposphere, and considering the known in-situ photochemical sources for methyl nitrate, the yield of methyl nitrate from the reaction of methyl peroxy radicals with NO was estimated. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Flocke, F (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. RI Aikin, Kenneth/I-1973-2013; Madronich, Sasha/D-3284-2015; Atlas, Elliot/J-8171-2015 OI Madronich, Sasha/0000-0003-0983-1313; NR 22 TC 26 Z9 26 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1891 EP 1894 DI 10.1029/98GL01417 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800034 ER PT J AU Harris, JM Oltmans, SJ Dlugokencky, EJ Novelli, PC Johnson, BJ Mefford, T AF Harris, JM Oltmans, SJ Dlugokencky, EJ Novelli, PC Johnson, BJ Mefford, T TI An investigation into the source of the springtime tropospheric ozone maximum at Mauna Loa Observatory SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC METHANE; BARROW AB Measurements of CH4, CO, O-3, and H2O vapor from Mauna Loa Observatory (MLO) are examined in conjunction with isentropic trajectories to investigate the cause of a maximum in tropospheric O-3 consistently observed during spring. CO and O-3 have been found to be positively correlated in pollution plumes containing O-3 precursors downwind of industrialized regions. However, we report that during continental transport from Asia, O-3 is not correlated with either CO or CH4, although CO and CH4 are strongly correlated. The relationship between CO and CH4 suggests common source regions. The lack of correlation between these species and O-3 probably indicates an O-3 source distinct from that of CO and CH4. While Asian pollution does not appear to be a strong candidate for causing the spring increase in O-3, transport characteristics and H2O vapor measurements are consistent with both an upper-tropospheric/stratospheric contribution and an enhancement from transport across O-3 gradients. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Harris, JM (reprint author), NOAA, Climate Monitoring & Diagnost Lab, R E CG1,325 Broadway, Boulder, CO 80303 USA. NR 17 TC 23 Z9 23 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 1895 EP 1898 DI 10.1029/98GL01410 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800035 ER PT J AU Hitchman, AP Lilley, FEM Campbell, WH AF Hitchman, AP Lilley, FEM Campbell, WH TI The quiet daily variation in the total magnetic field: global curves SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Most magnetic mapping exercises involve measuring the amplitude, or total-field component, of Earth's magnetic field. Removing the time-varying part of the field is a task of data reduction, and the most common time variation is the quiet daily variation, S-q. It is thus valuable to have for reference type curves of the quiet daily variation in the total field. To meet this need, global data obtained during the 1965 International Year of the Quiet Sun have been used to derive type curves describing the S-q variation of the total magnetic field, in addition to the traditional field components. As for the traditional components, the total-field curves show significant seasonal and latitudinal variability in amplitude and phase. The effect of the equatorial electrojet is clearly evident. In both hemispheres of the globe there are bands of reduced amplitude in total-field signal between the equator and the path of the S-q focus. These bands, here termed the total-field "doldrums", persist throughout the year. C1 Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. NOAA, Natl Geophys Data Ctr, World Data Ctr A, Boulder, CO 80303 USA. RP Hitchman, AP (reprint author), Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. NR 13 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1998 VL 25 IS 11 BP 2007 EP 2010 DI 10.1029/98GL51332 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZR962 UT WOS:000074033800063 ER PT J AU Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE Christian, LA Przybysz, JX AF Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE Christian, LA Przybysz, JX TI Pulse-driven Josephson digital/analog converter SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article DE array; D/A converter; digital/analog converter; Josephson; Josephson junction; pulse; quantization; superconductor; voltage standard ID JUNCTIONS AB The authors have designed and demonstrated a pulse-driven Josephson digital/analog converter. When used as a programmable voltage standard, this device can synthesize metrologically accurate ac waveforms as well as stable de voltages, We show through simulations that Josephson quantization produces a nearly ideal quantization noise spectrum when a junction is driven with a typical waveform produced by a digital code generator. This technique has been demonstrated in preliminary experiments with arrays of 1000 junctions clocked at frequencies up to 6 Gb/s, where sine waves of a few millivolts in amplitude were synthesized at frequencies up to 1 MHz. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Ind Res Ltd, Lower Hutt, New Zealand. Northrop Grumman STC, Pittsburgh, PA 15235 USA. RP Benz, SP (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 47 Z9 47 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1998 VL 8 IS 2 BP 42 EP 47 DI 10.1109/77.678440 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA ZQ887 UT WOS:000073913000001 ER PT J AU Paulter, NG AF Paulter, NG TI Low-jitter trigger system for pulse calibration and intercomparison of high-speed samplers SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE high-speed; pulse calibration; sampling oscilloscope; transition duration; trigger jitter; waveform recorder ID DECONVOLUTION; OSCILLOSCOPES AB A low-jitter (<1 ps) trigger system for pulse-waveform-based calibration and intercomparison of high-speed samplers is described. The system uses a commercially available pulse generator and pulse splitter/delay line. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Paulter, NG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 1998 VL 47 IS 3 BP 606 EP 608 DI 10.1109/19.744308 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 166CH UT WOS:000078558300001 ER PT J AU Paulter, NG AF Paulter, NG TI The effect of histogram size on histogram-derived pulse parameters SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE calibration; histogram; pulse parameters; reference standards; step-like waveforms; waveform recorders ID FAST SAMPLING OSCILLOSCOPES; CALIBRATION AB The effects of the number of histogram bins on histogram-derived pulse parameters of step-like waveforms is examined. An empirical method for selecting the optimal number of bins is described. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Paulter, NG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 1998 VL 47 IS 3 BP 609 EP 612 DI 10.1109/19.744309 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 166CH UT WOS:000078558300002 ER PT J AU Kiess, TE AF Kiess, TE TI Noise filtering of DC voltages in both the time and frequency domain SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE electric variables measurement; filters; frequency domain analysis; Gaussian noise; noise measurement; time domain measurements; uncertainty; voltmeters AB We describe a method of obtaining a smaller statistical uncertainty on the de component of a voltage signal by using a combination of time- and frequency-domain methods than by using time-domain averaging only. This measurement technique is compatible with precision de voltmeters that poll the input signal less than 100% of the time. The frequency-domain strategy captures information during the time that the voltmeter is not reading the input signal. Alternatively, one can map out low frequency noise spectra using this approach. C1 Natl Inst Stand & Technol, Div Elect, Gaithersburg, MD 20899 USA. RP Kiess, TE (reprint author), Natl Res Council, Washington, DC 20418 USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 1998 VL 47 IS 3 BP 674 EP 679 DI 10.1109/19.744322 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 166CH UT WOS:000078558300011 ER PT J AU Wong, DC Davis, EW Young, JO AF Wong, DC Davis, EW Young, JO TI A software approach to avoiding spatial cache collisions in parallel processor systems SO IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS LA English DT Article DE cache collision; cache offset; direct-mapped cache; highly parallel systems; sequential DO-loops AB In parallel processor systems, the performance of individual processors is a key factor in overall performance. Processor performance is strongly affected by the behavior of cache memory in that high hit rates are essential for high performance. Hit rates are lowered when collisions on placing lines in the cache force a cache line to be replaced before it has been used to best effect. Spatial cache collisions occur if data structures and data access patterns are misaligned. We describe a mathematical scheme to improve alignment and enhance performance in applications which have moderate-to-large numbers of arrays, where various dimensionalities are involved in localized computation and array access patterns are sequential. These properties are common in many computational modeling applications. Furthermore, the scheme provides a single solution when an application is targeted to run on various numbers of processors in power-of-two sizes. The applicability of the proposed scheme is demonstrated on testbed code for an air quality modeling problem. C1 N Carolina State Univ, Raleigh, NC 27695 USA. Natl Ocean & Atmospher Adm, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. RP Wong, DC (reprint author), N Carolina State Univ, Raleigh, NC 27695 USA. EM cwong@eos.ncsu.edu; davis@csc.ncsu.edu; yoj@hpcc.epa.gov NR 25 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1045-9219 EI 1558-2183 J9 IEEE T PARALL DISTR JI IEEE Trans. Parallel Distrib. Syst. PD JUN PY 1998 VL 9 IS 6 BP 601 EP 608 DI 10.1109/71.689447 PG 8 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA ZX913 UT WOS:000074568000009 ER PT J AU Young, GS Herman, M Hong, TH Jiang, D Yang, JCS AF Young, GS Herman, M Hong, TH Jiang, D Yang, JCS TI New visual invariants for terrain navigation without 3D reconstruction SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE autonomous vehicles; mobile robots; obstacle detection; optical flow; image motion; visual navigation; purposive vision ID MOTION AB For autonomous vehicles to achieve terrain navigation, obstacles must be discriminated from terrain before any path planning and obstacle avoidance activity is undertaken. In this paper, a novel approach to obstacle detection has been developed. The method finds obstacles in the 2D image space, as opposed to 3D reconstructed space, using optical flow. Our method assumes that both nonobstacle terrain regions, as well as regions with obstacles, will be visible in the imagery. Therefore, our goal is to discriminate between terrain regions with obstacles and terrain regions without obstacles. Our method uses new visual linear invariants based on optical flow. Employing the linear invariance property, obstacles can be directly detected by using reference flow lines obtained from measured optical flow. The main features of this approach are: (1) 2D visual information (i.e., optical flow) is directly used to detect obstacles; no range, 3D motion, or 3D scene geometry is recovered; (2) knowledge about the camera-to-ground coordinate transformation is not required; (3) knowledge about vehicle (or camera) motion is not required; (4) the method is valid for the vehicle (or camera) undergoing general six-degree-of-freedom motion; (5) the error sources involved are reduced to a minimum, because the only information required is one component of optical flow. Numerous experiments using both synthetic and real image data are presented. Our methods are demonstrated in both ground and air vehicle scenarios. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mech Engn, Robot Lab, College Pk, MD 20742 USA. RP Young, GS (reprint author), Natl Inst Stand & Technol, Bldg 220,Rm B124, Gaithersburg, MD 20899 USA. NR 46 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-5691 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD JUN PY 1998 VL 28 IS 1 BP 45 EP 71 DI 10.1023/A:1008002714698 PG 27 WC Computer Science, Artificial Intelligence SC Computer Science GA ZX971 UT WOS:000074573800003 ER PT J AU Grossman, EN Koch, JA Reintsema, CD Green, A AF Grossman, EN Koch, JA Reintsema, CD Green, A TI Lithographic dipole antenna properties at 10 mu m wavelength: Comparison of method-of-moments predictions with experiment SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE dipole; method-of-moments; lithographic antenna ID RADIATION AB Dipole antennas designed for operation at 10 mu m wavelength have been fabricated by optical lithography and their properties measured by detection of CO2 laser radiation in integrated thin-film bolometers. We find a remarkably strong increase in cross-polarized signal as the antenna linewidth is increased. The measured beam pattern is a saddle point at broadside (local minimum in the H-plane, local maximum in the E-plane) as predicted by standard method-of-moments theory. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Sci Applicat Int Corp, Maclean, VA USA. RP Grossman, EN (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 5 Z9 5 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD JUN PY 1998 VL 19 IS 6 BP 817 EP 825 DI 10.1023/A:1022620322622 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA ZQ944 UT WOS:000073918700003 ER PT J AU Fahey, AJ AF Fahey, AJ TI Details of the measurement of rare earth and other trace element abundances by secondary ion mass spectrometry SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE rare earth elements; quantitative secondary ion mass spectrometry ID REE; MICROPROBE; GEOCHEMISTRY; OLDHAMITE; AUBRITE; ORIGIN AB Details of a method for quantitative measurement of rare earth element (REE) abundances by secondary ion mass spectrometry are presented. The specifics of the multipass deconvolution algorithm are given. Direct measurements of the ratios of REE to REE oxide ion signals (eta(i)) as a function of energy are shown and investigated. The eta(i) are important quantities used to determine the intensities of the heavy REE ion signals. Relative sensitivity factors for the REE are given for silicate and sulfide minerals and a comparison of measured relative sensitivity factors among three laboratories is shown. The occurrence of artifacts in the analysis is also discussed. (Int J Mass Spectrom 176 (1998) 63-76) (C) 1998 Elsevier Science B.V. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Fahey, AJ (reprint author), NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Fahey, Albert/C-5611-2015 NR 18 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD JUN PY 1998 VL 176 IS 1-2 BP 63 EP 76 DI 10.1016/S1387-3806(98)14006-X PG 14 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 111YY UT WOS:000075467500005 ER PT J AU Calm, JM Didion, DA AF Calm, JM Didion, DA TI Trade-offs in refrigerant selections: past, present, and future SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE refrigerants; ozone depletion; greenhouse effect ID OZONE AB Recent attention to depletion of stratospheric ozone, by chemicals containing bromine and chlorine, resulted in an international accord to halt their production. The most widely used refrigerants are among them. Chemical and equipment manufacturers mounted aggressive research and development programs to introduce alternative and transition refrigerants, associated lubricants and desiccants, and redesigned equipment. The already difficult criteria became even more complex, with subsequent linkage of chemical emissions from human activities to global climate change. The very successful response to protect the ozone layer has led some regulators and users to assume that ideal substitutes will be found. Such chemicals should be free of all environmental and safety concerns, be chemically and thermally stable, and perform efficiently. The analyses presented in this paper demonstrate that the outlook for discovery or synthesis of ideal refrigerants is extremely unlikely. Trade-offs among desired objectives, therefore, are necessary to achieve balanced solutions. The paper also shows that fragmented regulation of the chemicals involved. to address individual issues, jeopardizes the prospect of solving subsequently addressed problems. The paper reviews the history of refrigerants, their roles in ozone depletion and global climate change, and necessary trade-offs in refrigerant selections. (C) 1998 Elsevier Science Ltd and IIR. All rights reserved. C1 US Dept Commerce, NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Didion, DA (reprint author), 10887 Woodleaf Lane, Great Falls, VA 22066 USA. NR 56 TC 46 Z9 49 U1 2 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD JUN PY 1998 VL 21 IS 4 BP 308 EP 321 DI 10.1016/S0140-7007(97)00089-3 PG 14 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA ZY902 UT WOS:000074674000006 ER PT J AU McLinden, MO Lemmon, EW Jacobsen, RT AF McLinden, MO Lemmon, EW Jacobsen, RT TI Thermodynamic properties for the alternative refrigerants SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article; Proceedings Paper CT ASHRAE//NIST Refrigerants Conference - Refrigerants for the 21st-Century CY OCT 06-07, 1997 CL GAITHERSBURG, MARYLAND SP ASHRAE, NIST DE refrigerants; mixtures; thermodynamics; equation of state ID VAPOR-LIQUID-EQUILIBRIUM; PLUS PENTAFLUOROETHANE R-32+125; PVTX PROPERTIES; NORMAL-BUTANE; PHASE PROPERTIES; MIXTURES; EQUATION; SYSTEM; STATE; DIFLUOROMETHANE AB Models commonly used to calculate the thermodynamic properties of refrigerants are summarized. For pure refrigerants, the virial, cubic, Martin-Hou, Benedict-Webb-Rubin. and Helmholtz energy equations of state and the extended corresponding states model are discussed. High-accuracy formulations for 16 refrigerants are recommended. These models may be extended to mixtures through the use of mixing rules applied either to the parameters of the equation of state or to some property of the mixture components. Mixtures of a specific composition may also be modeled as a pseudo-pure fluid. Five mixture models, employing four distinct approaches, have been compared by a group working under the auspices of the international Energy Agency. These comparisons show all five models to be very capable in representing mixture properties. No single model was best in all aspects, but based on its combination of excellent accuracy and great generality, we recommend the mixture Helmholtz energy model as the best available. Experimental data are essential to both fit the adjustable parameters in property models and to assess their accuracy. We present a survey of the data available for mixtures of the HFC refrigerants R32, R125, R143a, R134a, and R152a and for mixtures of the natural refrigerants propane, butane, isobutane, and carbon dioxide, More than 60 data references are identified. Further data needs include caloric data for additional mixtures, comprehensive pressure-density-temperature data for additional mixture compositions, and improved accuracy for vapor-liquid equilibria data. (C) 1998 Elsevier Science Ltd and IIR. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Idaho, Coll Engn, Moscow, ID 83844 USA. RP McLinden, MO (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 100 TC 21 Z9 22 U1 4 U2 14 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD JUN PY 1998 VL 21 IS 4 BP 322 EP 338 DI 10.1016/S0140-7007(97)00081-9 PG 17 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA ZY902 UT WOS:000074674000007 ER PT J AU Ehrman, SH Friedlander, SK Zachariah, MR AF Ehrman, SH Friedlander, SK Zachariah, MR TI Characteristics of SiO2/TiO2 nanocomposite particles formed in a premixed flat flame SO JOURNAL OF AEROSOL SCIENCE LA English DT Article; Proceedings Paper CT Joint NSF/JSPS Japan/US Workshop on Nanoparticle Synthesis and Application CY OCT 28-NOV 02, 1996 CL TSUKUBA, JAPAN SP NSF, JSPS ID MIXED-OXIDE POWDERS; CHEMICAL-KINETICS; AEROSOL REACTORS; TITANIA POWDERS; SURFACE-AREA; X-RAY; NUCLEATION; TIO2-SIO2; SILICA; GROWTH AB Nanometer sized (d(p) = 15 nm) SiO2/TiO2 particles were generated in a premixed flat flame aerosol reactor from three sets of precursors: SiBr4/TiCl4, SiCl4/TiCl4, and hexamethyl disiloxane (HMDS)/TiCl4. Single component silica and titania aerosols were also generated from SiBr4, SiCl4, HMDS and TiCl4. The choice of silica precursor had no observable effect on the particle size of the single component aerosols, or oil the distribution of species in the mixed aerosol, as determined by transmission electron microscopy (TEM) and by interparticle chemical analysis of the mixed aerosol using energy dispersive X-ray spectrometry (EDS). These results suggest that for this flame configuration, chemical processes are not rate determining for particle size and do not affect the arrangement of species for mixed systems. Within the particles, small (3-12 nm in diameter) crystalline regions enriched in titanium were observed using electron energy loss spectrometry (EELS) coupled with scanning transmission electron microscopy (STEM). A mechanism in which segregation occurs during particle growth by diffusion within the particles is proposed. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Angeles, Aersol Technol Air Qual Lab, Dept Chem Engn, Los Angeles, CA 90095 USA. NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Friedlander, SK (reprint author), Univ Calif Los Angeles, Aersol Technol Air Qual Lab, Dept Chem Engn, 5531 Boelter Hall, Los Angeles, CA 90095 USA. NR 62 TC 96 Z9 100 U1 1 U2 14 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD JUN-JUL PY 1998 VL 29 IS 5-6 BP 687 EP 706 DI 10.1016/S0021-8502(97)00454-0 PG 20 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZT632 UT WOS:000074107300017 ER PT J AU Glinka, CJ Barker, JG Hammouda, B Krueger, S Moyer, JJ Orts, WJ AF Glinka, CJ Barker, JG Hammouda, B Krueger, S Moyer, JJ Orts, WJ TI The 30 m small-angle neutron scattering instruments at the National Institute of Standards and Technology SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID VELOCITY SELECTORS; OPTIMIZATION; RESOLUTION AB Two high-resolution, general-purpose, small-angle neutron scattering instruments have been constructed at the National Institute of Standards and Technology's Center for Neutron Research. The instruments are 30 m long and utilize mechanical velocity selectors, pinhole collimation and high-data-rate two-dimensional position-sensitive neutron detectors. The incident wavelength, wavelength resolution and effective length of the instruments are independently variable, under computer control, and provide considerable flexibility in optimizing beam intensity and resolution. The measurement range of the instruments extends from 0.0015 to 0.6 Angstrom(-1) in scattering wavevector, corresponding to structure in materials from 10 Angstrom to nearly 4000 Angstrom. The design and characteristics of the instruments, and their modes of operation, are described, and data are presented which demonstrate their performance. C1 Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Glinka, CJ (reprint author), Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 19 TC 432 Z9 434 U1 0 U2 28 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 1998 VL 31 BP 430 EP 445 DI 10.1107/S0021889897017020 PN 3 PG 16 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 113DA UT WOS:000075533500018 ER PT J AU Li, WH Peng, JC Lin, YC Lee, KC Lynn, JW Chen, YY AF Li, WH Peng, JC Lin, YC Lee, KC Lynn, JW Chen, YY TI Magnetic ordering of Ce in the heavy-fermion compound Ce3Al SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID BEHAVIOR; SYSTEMS AB Neutron diffraction and specific heat measurements have been performed to study the magnetic ordering of the Ce ions in the heavy-fermion compound Ce3Al. Detailed crystal structure analysis, determined using high resolution neutron diffraction patterns and Rietveld method, shows that the Ce ions may be grouped into two types: one in the Ce-Al chain, the other in the Ce-Ce chain. The specific-heat data reveal an anomaly at T approximate to 2.2 K, but the calculated magnetic entropy is much smaller than the expected R ln 2 if all Ce spins ordered, Low temperature neutron diffraction measurements confirm that the transition at 2.2 K is magnetic and is associated with the ordering of the Ce spins. The magnetic unit cell is double the nuclear one along the a and c axes, and contains 48 Ce ions, Only the Ce ions in the Ce-Al chains participate in the ordering at 2.2 K, and they are coupled antiferromagnetically. (C) 1998 American Institute of Physics. [S0021-8979(98)21011-5]. C1 Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Acad Sinica, Inst Phys, Taipei 115, Taiwan. RP Li, WH (reprint author), Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. NR 9 TC 2 Z9 2 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6426 EP 6428 DI 10.1063/1.367575 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500067 ER PT J AU Donahue, MJ AF Donahue, MJ TI A variational approach to exchange energy calculations in micromagnetics SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETIC STRIPS AB This article presents a magnetization interpolation method for micromagnetic exchange energy calculations using a variational procedure to relax spins on a supplemental (refined) lattice. The approximations implicit in standard micromagnetic discretization schemes fail when angles between neighboring spins in the model become large, but the proposed approach effectively reduces the angle between neighboring spins, alleviating many of the associated problems. Moreover, this method does not introduce excessive discretization-induced vortex pinning observed with some large angle exchange energy formulations. This article includes details on proper post-interpolation exchange torque calculation, bounds on nearest-neighbor angles for interpolated lattices, a simple model predicting discretization-induced Neel wall collapse, and an example of a collapsed (1 cell wide) domain wall that can be restored by the proposed technique. [S0021-8979(98)33311-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Donahue, MJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 6 TC 19 Z9 19 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6491 EP 6493 DI 10.1063/1.367690 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500089 ER PT J AU Harris, VG Fatemi, DJ Browning, VM Osofsky, MS Vanderah, TA AF Harris, VG Fatemi, DJ Browning, VM Osofsky, MS Vanderah, TA TI Extended x-ray absorption fine structure measurements of nonsuperconducting PrBa2Cu3O6.9: Evidence against Ba site Pr substitution SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID ELECTRONIC-STRUCTURE; SUPERCONDUCTIVITY; HYBRIDIZATION; TEMPERATURE; SUPPRESSION; SCATTERING; ORDER AB Extended x-ray absorption fine structure (EXAFS) measurements on nonsuperconducting PrBa2Cu3O6.9 are reported. Theoretical Pr L-II EXAFS data, calculated for the case of Y-site and Ba-site occupation, were least-squares fit to the experimental Pr L-II EXAFS. Results indicate that the Pr ions overwhelmingly occupy the Y sites. These results present a serious challenge to models which rely on Ba-site Pr substitution as an explanation for the lack of superconductivity in PrBa2Cu3O6.9. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Harris, VG (reprint author), USN, Res Lab, Washington, DC 20375 USA. RI Harris, Vincent/A-8337-2009; Osofsky, Michael/A-1050-2010 NR 20 TC 8 Z9 8 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6783 EP 6785 DI 10.1063/1.367709 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500187 ER PT J AU Nikitenko, VI Gornakov, VS Dedukh, LM Kabanov, YP Khapikov, AF Shapiro, AJ Shull, RD Chaiken, A Michel, RP AF Nikitenko, VI Gornakov, VS Dedukh, LM Kabanov, YP Khapikov, AF Shapiro, AJ Shull, RD Chaiken, A Michel, RP TI Direct experimental study of the magnetization reversal process in epitaxial and polycrystalline films with unidirectional anisotropy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID EXCHANGE-ANISOTROPY; DEPENDENCE; INTERFACES; BILAYERS; DISORDER; NIO AB Direct observation of the magnetization reversal of epitaxial NiO/NiFe bilayers grown on (001) MgO and on polycrystalline Si substrates was performed by using the magneto-optical indicator film technique. It was shown that the unidirectional-axis magnetization reversal proceeds by domain nucleation and growth. A new phenomenon, an asymmetry in the activity of the domain nucleation centers, has been revealed. Remagnetization of the bilayer is shown to be governed by defect structures in the antiferromagnetic layer. (C) 1998 American Institute of Physics. C1 Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Moscow District, Russia. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Univ Calif Lawrence Livermore Natl Lab, Div Mat Sci & Technol, Livermore, CA 94551 USA. RP Nikitenko, VI (reprint author), Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Moscow District, Russia. EM shapiro@enh.nist.gov RI Shull, Robert/F-5971-2013 NR 15 TC 19 Z9 19 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6828 EP 6830 DI 10.1063/1.367663 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500202 ER PT J AU Ijiri, Y Borchers, JA Erwin, RW Lee, SH van der Zaag, PJ Wolf, RM AF Ijiri, Y Borchers, JA Erwin, RW Lee, SH van der Zaag, PJ Wolf, RM TI Role of the antiferromagnet in exchange-biased Fe3O4/CoO superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID GROWN NI80FE20/FE50MN50 BILAYERS; MAGNETIC-PROPERTIES; FEF2-FE BILAYERS; FILMS; ANISOTROPY; DEPENDENCE; INTERFACES; ORDER AB Using neutron diffraction techniques, we have directly characterized the antiferromagnetic spin structure of CoO in exchange-biased Fe3O4/CoO (001) superlattices. The CoO antiferromagnetic order is long-range and extends coherently across intervening ferrimagnetic Fe3O4 layers. The ordering is influenced significantly by not only epitaxial growth constraints but also by couplings to the Fe3O4 layers. The antiferromagnetic order in these Fe3O4/CoO (001) samples exhibits significant dependence on field cooling preparations. The CoO spins show a strong tendency to align perpendicular to the net ferrimagnetic moment with some changes in the average domain size associated with field cooling. The CoO spin structure in the exchange-biased state illustrates important aspects of recent biasing theories but with unusually large domain sizes. (C) 1998 American Institute of Physics. [S0021-8979(98)17811-8]. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Philips Res Labs, NL-5656 AA Eindhoven, Netherlands. RP Ijiri, Y (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI van der Zaag, Pieter/F-7431-2014 OI van der Zaag, Pieter/0000-0001-9080-4907 NR 26 TC 18 Z9 18 U1 2 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 6882 EP 6887 DI 10.1063/1.367962 PN 2 PG 6 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500220 ER PT J AU McMichael, RD Stiles, MD Chen, PJ Egelhoff, WF AF McMichael, RD Stiles, MD Chen, PJ Egelhoff, WF TI Ferromagnetic resonance linewidth in thin films coupled to NiO SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc AB The out-of-plane angular dependence of the ferromagnetic resonance linewidth, Delta H, has been measured for thin magnetic films coupled to NiO and for uncoupled control films. In the control films, Delta H is described by nearly angle-independent damping parameters. In the NiO-coupled films, however, the damping was found to depend strongly on magnetization orientation, with linewidth values comparable to the control samples at normal orientation, but several times larger when the magnetization lies in plane. The additional linewidth in the NiO-coupled films follows the angular dependence of the number of nearly degenerate spin wave modes, in agreement with the predictions of a two-magnon scattering model of damping which incorporates a spin wave dispersion relation suitable for ultrathin films. (C) 1998 American Institute of Physics. [S0021-8979(98)37811-1]. C1 NIST, Gaithersburg, MD 20899 USA. RP McMichael, RD (reprint author), NIST, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012; Stiles, Mark/K-2426-2012; OI Stiles, Mark/0000-0001-8238-4156; McMichael, Robert/0000-0002-1372-664X NR 12 TC 92 Z9 92 U1 2 U2 17 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7037 EP 7039 DI 10.1063/1.367725 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500271 ER PT J AU Borchers, JA Ijiri, Y Lee, SH Majkrzak, CF Felcher, GP Takano, K Kodama, RH Berkowitz, AE AF Borchers, JA Ijiri, Y Lee, SH Majkrzak, CF Felcher, GP Takano, K Kodama, RH Berkowitz, AE TI Spin-flop tendencies in exchange-biased Co/CoO thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID BILAYERS; SUPERLATTICES; ANISOTROPY; NIO AB In order to study the antiferromagnetic (AFM) spin structure near the interface of exchange-biased bilayers, polarized neutron diffraction measurements were performed on a series of (111)Co(7.5 nm)/CoO (X nm) and CoO (X nm) thin films where X = 20, 40, and 100 nm. In these samples, field cooling through the Neel temperature of the AFM increases the component of the CoO moment perpendicular to the applied field, relative to the parallel component. The subsequent application of a 500 Oe field perpendicular to the cooling direction rotates both the Co and CoO moments. Experiments on CoO films without Co showed a smaller difference between the parallel and perpendicular CoO moments in response to cooling and applied fields. Exchange coupling between the Co and CoO layers is apparently responsible for the increased projection of the AFM moments perpendicular to the cooling field. (C) 1998 American Institute of Physics. C1 NIST, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 94720 USA. RP Borchers, JA (reprint author), NIST, Gaithersburg, MD 20899 USA. EM borchers@rrdstrad.nist.gov NR 16 TC 20 Z9 20 U1 0 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7219 EP 7221 DI 10.1063/1.367939 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500332 ER PT J AU Vasiliu-Doloc, L Lynn, JW Mukovskii, YM Arsenov, AA Shulyatev, DA AF Vasiliu-Doloc, L Lynn, JW Mukovskii, YM Arsenov, AA Shulyatev, DA TI Spin dynamics of strongly doped La1-xSrxMnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID DOUBLE-EXCHANGE; LA1-XCAXMNO3; FERROMAGNET AB Cold neutron triple-axis measurements have been used to investigate the nature of the long-wavelength spin dynamics in strongly doped La1-xSrxMnO3 single crystals with x = 0.2 and 0.3. Both systems behave like isotropic ferromagnets at low T, with a gapless (E-0<0.02 meV) quadratic dispersion relation E = E-0 + Dq(2). The values of the spin-wave stiffness constant D are large (D-T=0 = 167 meV Angstrom(2) for x = 0.2 and D-T=0 = 176 meV Angstrom(2) for x = 0.3), which directly shows that the electron transfer energy for the d band is large. D exhibits a power law behavior as a function of temperature, and appears to collapse as T-->T-C Te. Nevertheless, an anomalously strong quasielastic central component develops and dominates the fluctuation spectrum as T-->T-C. Bragg scattering indicates that the magnetization near T-C exhibits power law behavior, with beta similar or equal to 0.30 for both systems, as expected for a three-dimensional ferromagnet. (C) 1998 American Institute of Physics. C1 Natl Inst Stand & Technol, Ctr Neuron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Ctr Superconduct Res, College Pk, MD 20742 USA. Moscow Steel & Alloys Inst, Moscow 117936, Russia. RP Vasiliu-Doloc, L (reprint author), Natl Inst Stand & Technol, Ctr Neuron Res, Gaithersburg, MD 20899 USA. RI Shulyatev, Dmitry/M-7278-2014 OI Shulyatev, Dmitry/0000-0002-7642-0277 NR 16 TC 37 Z9 37 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7342 EP 7344 DI 10.1063/1.367634 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500372 ER PT J AU Wu, SY Li, WH Lee, KC Lynn, JW Liu, RS Wu, JB Huang, CY AF Wu, SY Li, WH Lee, KC Lynn, JW Liu, RS Wu, JB Huang, CY TI Tilted antiferromagnetic ordering of Mn in Nd0.62Ca0.38MnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID MAGNETORESISTANCE; VALENCE AB The magnetic ordering of the Mn spins in polycrystalline Nd0.62Ca0.38MnO3 has been investigated by means of neutron diffraction and ac magnetic susceptibility measurements. Three peaks around 230, 90, and 40 K were observed in the temperature dependence of the in-phase component of the ac susceptibility, chi '(T). Neutron diffraction measurements show that the peak at 90 K is associated with the ordering of the Mn spins, and that at 40 K is due to the reorientation of the Mn spins. Both ferromagnetic and antiferromagnetic coupling between the Mn spins were observed. The spins order at T-N approximate to 130 K, with a spin structure consisting of ferromagnetically coupled, tilted antiferromagnetic sheets. No evidence was found from the neutron diffraction data to indicate that the peak around 230 K in chi '(T) is of magnetic origin, which suggests that it is associated with charge ordering. (C) 1998 American Institute of Physics. C1 Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan. Natl Taiwan Univ, Ctr Condensed Matter Sci, Taipei 106, Taiwan. Natl Taiwan Univ, Dept Phys, Taipei 106, Taiwan. RP Wu, SY (reprint author), Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. RI Liu, Ru-Shi/A-6796-2010 OI Liu, Ru-Shi/0000-0002-1291-9052 NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7345 EP 7347 DI 10.1063/1.367635 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500373 ER PT J AU Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK Argyriou, DN AF Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK Argyriou, DN TI Magnetic correlations in the bilayer manganite La1.2Sr1.8Mn2O7 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 7th Joint Magnetism and Magnetic Materials / International Magnetics Conference CY JAN 06-09, 1998 CL SAN FRANCISCO, CALIFORNIA SP Amer Inst Phys, IEEE Magnet Soc, TMS, Off Naval Res, Amer Soc Testing & Mat, Amer Ceram Soc ID GIANT MAGNETORESISTANCE; EXCHANGE AB Neutron scattering has been used to study the magnetic correlations in the double-layer manganite La1.2Sr1.8Mn2O7, which exhibits colossal magnetoresistance in the vicinity of the ferromagnetic transition at T-c = 112 K. Over a large temperature range above T-c, there is evidence for two-dimensional magnetic correlations which peak in intensity at the transition. Although the in-plane correlations are predominantly ferromagnetic, a strong canting of spins in neighboring planes within the bilayers, at an angle that is dependent on both the temperature and magnetic field, is observed. There are indications of a crossover to three-dimensional critical scattering very close to T-c, but the nature of the phase transition has yet to be determined. (C) 1998 American Institute of Physics. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos Neutron Sci Ctr, Los Alamos, NM 87545 USA. Univ Maryland, College Pk, MD 20742 USA. RP Rosenkranz, S (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383 NR 15 TC 22 Z9 22 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1998 VL 83 IS 11 BP 7348 EP 7350 DI 10.1063/1.367796 PN 2 PG 3 WC Physics, Applied SC Physics GA 152UQ UT WOS:000077795500374 ER PT J AU Arkoosh, MR Casillas, E Clemons, E Kagley, AN Olson, R Reno, P Stein, JE AF Arkoosh, MR Casillas, E Clemons, E Kagley, AN Olson, R Reno, P Stein, JE TI Effect of pollution on fish diseases: Potential impacts on salmonid populations SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article; Proceedings Paper CT Symposium on Pathogens and Diseases of Fish in Aquatic Ecosystems - Implications in Fisheries Management CY JUN 03-04, 1997 CL PORTLAND, OREGON SP Pacific NW Fish Hlth Protect Comm, Alaska Fish & Game, Amer Fisheries Soc, Colorado Wyoming Chapter, Amer Fisheries Soc, Fish Hlth Sect, BioProd, Clear Springs Foods Inc, Idaho Aquaculture Assoc, Montana Dept Fish Wildlife & Parks, Moore Clark, Muckelshoot Indian Tribe, Keta Creek Hatchery, Natl Marine Fisheries Serv, Nelson & Sons, Nisqually Indian Tribe, Clear Springs Hatchery, Oregon Dept Fish & Wildlife, Oregon State Univ, Suquamish Indian Tribe, Trout Unlimited, Univ Idaho, US Fish & Wildlife Serv, Washington Dept Fish & Wildlife, Western Chem, Western Fisheries Res Ctr, US Geol Survey, Western Reg Aquaculture Consortium, Whirling Dis Fdn ID JUVENILE CHINOOK SALMON; BACTERIAL KIDNEY-DISEASE; ONCORHYNCHUS-TSHAWYTSCHA; PACIFIC SALMON; EXPOSURE; WASHINGTON; IMMUNITY; URBAN AB Anthropogenic factors have contributed to the precipitous decline of wild Pacific salmon stocks, although the mechanisms and processes at work are largely unknown. Pollution may be one of these factors. Sediments in estuaries are known to act as repositories for contaminants, and estuaries are important habitats for ocean-and river-migrating salmon. We have shown that juvenile salmon Oncorhynchus spp. and their prey bioaccumulate chlorinated hydrocarbons and aromatic hydrocarbons-important classes of toxic xenobiotics. Furthermore, we have shown that exposure to these pollutants can lead to immunosuppression and increased disease susceptibility in juvenile salmon. Whether pollution influences natural disease outbreaks in host populations, including salmon, is currently unknown. It is postulated that the occurrence of disease depends on the interaction of the host, the environment, and the pathogen. Absence of pathogens would reduce the potential for adverse environments to influence disease outbreaks. However, a recent reconnaissance survey of juvenile chinook salmon Oncorhynchus tshawytscha from Oregon coastal rivers revealed that pathogens were an integral component in all systems studied, although the prevalence of the pathogens varied. Furthermore, recent studies of natural fish populations have demonstrated that infectious-disease-induced mortality can significantly reduce the size of the host population. By creating adverse environments (e.g., polluted estuaries) which alter the susceptibility of the host to pathogens that are integral and ubiquitous components of the habitat, pollution increases the probability of disease-related impacts on fish populations. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. Oregon State Univ, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Arkoosh, MR (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Hatfield Marine Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 32 TC 80 Z9 83 U1 3 U2 23 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD JUN PY 1998 VL 10 IS 2 BP 182 EP 190 DI 10.1577/1548-8667(1998)010<0182:EOPOFD>2.0.CO;2 PG 9 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA ZU180 UT WOS:000074170300012 ER PT J AU Belnap, J Gillette, DA AF Belnap, J Gillette, DA TI Vulnerability of desert biological soil crusts to wind erosion: the influences of crust development, soil texture, and disturbance SO JOURNAL OF ARID ENVIRONMENTS LA English DT Article; Proceedings Paper CT International Symposium and Workshop on Combating Desertification - Connecting Science with Community Action CY MAY 12-16, 1997 CL TUCSON, ARIZONA SP US Dept Interior, Bureau Land Management, Int Arid Lands Consortium, Univ Arizona, USDA, Agr Res Serv, US EPA, Ctr Investigaciones Desertificacion, Desert Res Inst, Int Fund Agr Dev, Bur Land Management Natl Appl Resource Sci Ctr, US Agcy Int Dev, UN Environm Programme, UN Convent Combat Desertificat, Interim Secretariat, European Soc Soil Conservat DE cryptogamic; microbiotic; microphytic; cyanobacteria; lichens; soil loss; wind erosion; land degradation AB Biological soil crusts, consisting of cyanobacteria, green algae, lichens, and mosses, are important in stabilizing soils in semi-arid and arid lands. Integrity of these crusts is compromised by compressional disturbances such as foot, vehicle, or livestock traffic. Using a portable wind tunnel, we found threshold friction velocities (TFVs) of undisturbed crusts well above wind forces experienced at these sites; consequently, these soils are not vulnerable to wind erosion. However, recently disturbed soils or soils with less well-developed crusts frequently experience wind speeds that exceed the stability thresholds of the crusts. Crustal biomass is concentrated in the top 3 mm of soils. Sandblasting by wind can quickly remove this material, thereby reducing N and C inputs from these organisms. This loss can result in reduced site productivity, as well as exposure of unprotected subsurface sediments to wind and water erosion. Actions to reduce impacts to these crusts can include adjustments in type, intensity, and timing of use. (C)1998 Academic Press Limited. C1 US Geol Survey, Biol Resources Div, Moab, UT 84532 USA. NOAA, Air Resources Lab, Res Triangle Pk, NC 27711 USA. NOAA, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. RP Belnap, J (reprint author), US Geol Survey, Biol Resources Div, 2282 S Resource Blvd, Moab, UT 84532 USA. NR 28 TC 240 Z9 282 U1 11 U2 97 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0140-1963 J9 J ARID ENVIRON JI J. Arid. Environ. PD JUN PY 1998 VL 39 IS 2 BP 133 EP 142 DI 10.1006/jare.1998.0388 PG 10 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA ZZ989 UT WOS:000074789600005 ER PT J AU Ryzhkov, A Zrnic, D AF Ryzhkov, A Zrnic, D TI Beamwidth effects on the differential phase measurements of rain SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID MELTING LAYER; PRECIPITATION; RADAR AB Effects of beamfilling nonuniformities on the differential phase and rainfall estimation that use specific differential phase are examined. Two physical models are considered: an isolated rain cell with azimuthal dimensions comparable to the beamwidth and a sharp, rain boundary approximating a squall line. The model results are compared to observations. An extension of the analysis to include observations of the melting layer is made. From this analysis emerges an interpretation of the radial profile of differential phase that varies from previous explanations. The current interpretation might be favored due to its simplicity and reliance on accepted physical properties of the melting layer. C1 Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, NSSL, Norman, OK 73069 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Ryzhkov, A (reprint author), Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, NSSL, 1313 Halley Circle, Norman, OK 73069 USA. NR 14 TC 27 Z9 28 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 624 EP 634 DI 10.1175/1520-0426(1998)015<0624:BEOTDP>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300002 ER PT J AU Breaker, LC Gilhousen, DB Burroughs, LD AF Breaker, LC Gilhousen, DB Burroughs, LD TI Preliminary results from long-term measurements of atmospheric moisture in the marine boundary layer in the Gulf of Mexico SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RETURN-FLOW; SEA AB Measurements of boundary layer moisture have been acquired from Rotronic MP-100 sensors deployed on two National Data Buoy Center (NDBC) buoys in the northern Gulf of Mexico from June through November 1993. For one sensor that was retrieved approximately 8 months after deployment and a second sensor that was retrieved about 14 months after deployment, the pre- and postcalibrations agreed closely and fell within WMO specifications for accuracy. A second Rotronic senor on one of the buoys provided the basis for a detailed comparison of the instruments and showed close agreement. A separate comparison of the Rotronic instrument with an HO-83 hygrometer at NDBC showed gene ally close agreement over a 1-month period, which included a number of fog events. The buoy observations of relative humidity and supporting data from the buoys were used to calculate specific humidity. Specific humidities from the buoys were compared with specific humidities computed from observations obtained from nearby ship reports, and the correlations were generally high (0.7-0.9). Uncertainties in the calculated values of spec fic humidity were also estimated and ranged between 0.27% and 2.1% of the mean value, depending on the method used to estimate this quantity. The time series of specific humidity revealed th ee primary scales of variability: small scale (of the order of hours), synoptic scale (several days), and seasonal (several months). The synoptic-scale variability was clearly dominant; it was eventlike in character and occurred primarily during September, October, and November. Most of the synoptic-scale variability was due to frontal systems that dropped down into the Gulf of Mexico from the continental United States, followed by air mas;es that were cold and dry. One particularly intense event on 30 October 1993 was chosen for a more detailed;analysis in terms of the characteristic return-flow cycles that occur in the northern Gulf of Mexico during fail and winter. Finally, cross-correlation analyses of the buoy data indicated that the prevailing weather systems generally entered the buoy domain from the south prior to September; thereafter, they became more coherent and tended To enter the region from the north. C1 NOAA, NCEP, EMC, Ocean Modeling Branch,Natl Weather Serv, Camp Springs, MD 20748 USA. NOAA, Natl Data Baoy Ctr, Natl Weather Serv, Stennis Space Ctr, MS USA. RP Breaker, LC (reprint author), NOAA, NCEP, EMC, Ocean Modeling Branch,Natl Weather Serv, 5200 Auth Road, Camp Springs, MD 20748 USA. NR 22 TC 9 Z9 9 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 661 EP 676 DI 10.1175/1520-0426(1998)015<0661:PRFLTM>2.0.CO;2 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300005 ER PT J AU Philipona, R Frohlich, C Dehne, K DeLuisi, J Augustine, J Dutton, E Nelson, D Forgan, B Novotny, P Hickey, J Love, SP Bender, S McArthur, B Ohmura, A Seymour, JH Foot, JS Shiobara, M Valero, FPJ Strawa, AW AF Philipona, R Frohlich, C Dehne, K DeLuisi, J Augustine, J Dutton, E Nelson, D Forgan, B Novotny, P Hickey, J Love, SP Bender, S McArthur, B Ohmura, A Seymour, JH Foot, JS Shiobara, M Valero, FPJ Strawa, AW TI The Baseline Surface Radiation Network pyrgeometer round-robin calibration experiment SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID PERFORMANCE; ACCURACY AB With the aim of improving the consistency of terrestrial and atmospheric longwave radiation measurements within the Baseline Surface Radiation Network, five: Eppley Precision Infrared Radiometer (PIR) pyrgeometers and one modified Mereorological Research Flight (MRF) pyrgeometer were individually calibrated by 11 specialist laboratories. The round-robin experiment was conducted in a "blind" sense in that the participants had no knowledge of the results of others until the wholl: series of calibrations had ended. The responsivities C(mu V/W m(-2)) determined by 6 of the 11 institutes were within about 2% of the median for all five PIR pyrgeometers. Among the six laboratories, the absolute deviation around the median of the deviations of the five instruments is less than 1%. This small scatter suggests that PII: pyrgeometers were stable at least during the two years of the experiment and that the six different calibration devices reproduce the responsivity C of PIR pyrgeometers consistently and within the precision required for climate applications. The results also suggest that the responsivity C can be determined without simultaneous determination of the dome correction factor k, if the temperature difference between pyrgeometer body and dome is negligible during calibration. For field measurements, however, k has to be precisely known. The calibration of the MRF pyrgeometer, although not performed by all institutes, also showed satisfactory results. C1 World Radiat Ctr, Phys Meteorolog Observ, CH-7260 Davos Dorf, Switzerland. Meteorolog Observat Potsdam, Potsdam, Germany. SRRB, Appl Res Lab, NOAA, Boulder, CO USA. CMDL, NOAA, Boulder, CO USA. Bur Meteorol, Melbourne, Vic, Australia. Eppley Lab, Newport, RI USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. Atmospher Environm Serv, Downsview, ON, Canada. ETH Zurich, Inst Geophys, CH-8093 Zurich, Switzerland. Meteorol Res Flight, Farnborough, Hants, England. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Philipona, R (reprint author), World Radiat Ctr, Phys Meteorolog Observ, Dorfstr 33, CH-7260 Davos Dorf, Switzerland. NR 16 TC 34 Z9 34 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 687 EP 696 DI 10.1175/1520-0426(1998)015<0687:TBSRNP>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300007 ER PT J AU Smirnov, AV AF Smirnov, AV TI Ocean radar observations of ship-induced instabilities in the atmospheric boundary layer SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID VORTICES; FIRES AB Both natural and artificial (ship induced) features of atmospheric motions can be seen in ocean radar imagery. Observations of a surface wake extending downstream from the atmospheric vortices in a thermal ship plume are described. To demonstrate the usefulness of radar systems in observing the ocean surface, the authors studied hot ship exhaust using a 2.25-cm-wavelength airborne radar. The ship-induced feature in the polarimetric radar images was observed in the ocean surface cold environment with moderate horizontal ambient winds. The smokelike feature appears only in the vertically polarized images, not in the horizontally polarized images. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Environm Technol Lab, Boulder, CO 80303 USA. RP Smirnov, AV (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 798 EP 803 DI 10.1175/1520-0426(1998)015<0798:OROOSI>2.0.CO;2 PG 6 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300016 ER PT J AU Strauch, RG Frehlich, R AF Strauch, RG Frehlich, R TI Doppler weather radar velocity measurements using a single pulse SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID BACKSCATTER HETERODYNE LIDAR; SPECTRAL PEAK ESTIMATION; ACCUMULATION; PERFORMANCE; SIMULATION; SIGNALS AB Simulations of weather radar echoes were used to determine whether single-pulse estimates of velocity could br made with sufficient accuracy to measure the velocity aliasing that is inherent with pulse Doppler weather radars. The results indicated that; this type of velocity measurement can be made. but such a large number of sincere-pulse estimates need to be averaged to determine the velocity aliasing that the concept is not compatible with the spatial and temporal resolution requirements of the WSR-88D (NEXRAD). C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Strauch, RG (reprint author), NOAA, ERL, ETL, R-E-ET4,325 Broadway, Boulder, CO 80303 USA. NR 13 TC 2 Z9 2 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 804 EP 808 DI 10.1175/1520-0426(1998)015<0804:DWRVMU>2.0.CO;2 PG 5 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300017 ER PT J AU Angevine, WM Bakwin, PS Davis, KJ AF Angevine, WM Bakwin, PS Davis, KJ TI Wind profiler and RASS measurements compared with measurements from a 450-m-tall tower SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID BOUNDARY-LAYER; HEAT-FLUX; TEMPERATURE; AIR AB A 915-MHz boundary layer wind profiler with radio acoustic sounding system (RASS) was sited 8 km from a very tall (450 m) television transmitting tower in north-central Wisconsin during the spring, summer, and autumn of 1995. The profiler measured wind means and variances, and the RASS attachment measured virtual temperature. These quantities are compared to measurements from cup and sonic anemometers and a thermometer/hygrometer at 396 m above ground level on the tower. The precision of hour-averaged profiler winds is better than 1 rn s(-1), and the precision of the RASS virtual temperature is better than 0.9 K. Corrections to die virtual temperature measured by the RASS are discussed, and a new virtual temperature retrieval method is proposed. Vertical velocity variance correlation is similar to a previous study, and the fact that bias is small indicates that the calculation method used is reliable. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO USA. RP Angevine, WM (reprint author), NOAA, Aeron Lab, R-E-AL3,325 Broadway, Boulder, CO 80303 USA. RI Angevine, Wayne/H-9849-2013 OI Angevine, Wayne/0000-0002-8021-7116 NR 19 TC 43 Z9 45 U1 0 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 818 EP 825 DI 10.1175/1520-0426(1998)015<0818:WPARMC>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300019 ER PT J AU Hartten, LM AF Hartten, LM TI Reconciliation of surface and profiler winds at ISS sites SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID TROPICAL WESTERN PACIFIC; TOGA-COARE; BOUNDARY-LAYER; VARIABILITY AB Integrated Sounding Systems (ISSs), which combine surface-based, balloon-borne, and radar observation capabilities, were deployed for the first time during the Intensive Observing Period (IOP) of the recent Coupled Ocean-Atmosphere Response Experiment. This note addresses efforts to synthesize the data from these disparate platforms as well as avenues for future research that were opened in the process. The collaborative nature of the ISSs led to the application of different processing methods to the surface winds than were used with the winds measured by 915-MHz wind profilers. A new set of ship-based surface winds that are more directly analogous to the profiler winds has been developed. The statistical properties of these "AL-processed ISS surface winds" are shown to be similar to those of the land-based ISS surface winds, to the low-level profiler winds, and to surface winds measured at nearby buoys. A method of combining the surface and profiler winds from an ISS into one coherent dataset is also presented here, it involves assuming a logarithmic wind profile over a surface layer whose depth is invariant over the course of the IOP. While there are some obvious oversimplifications to this method, it is the most sophisticated option available from currently collected ISS data. it is more physically reasonable than a simple linear interpolation between the surface and higher-altitude winds, and it yields wind profiles that are acceptable for many applications. Both of these new datasets are now available to the community. The process of combining the two sets of measurements not only led to a reconsideration of the postprocessing of the shipboard surface winds but also led to renewed interest : In the effects of sea clutter on profiler winds. Further work is now under way in the profiler community to address the issue of sea clutter on ship-based and near-sea profiler installations. C1 Univ Colorado, NOAA, Aeron Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Hartten, LM (reprint author), Univ Colorado, NOAA, Aeron Lab, Cooperat Inst Res Environm Sci, Campus Box 216, Boulder, CO 80309 USA. RI Hartten, Leslie/F-1970-2010 OI Hartten, Leslie/0000-0002-5620-6302 NR 14 TC 9 Z9 9 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1998 VL 15 IS 3 BP 826 EP 834 DI 10.1175/1520-0426(1998)015<0826:ROSAPW>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA ZQ890 UT WOS:000073913300020 ER PT J AU Tewari, YB Kishore, N Goldberg, RN Luong, TN AF Tewari, YB Kishore, N Goldberg, RN Luong, TN TI An equilibrium and calorimetric study of some transamination reactions SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE L-alanine; aminotransferase; enthalpy; equilibrium constant; L-glutamate; 4-hydroxyphenylpyruvate; 2-oxoglutarate; L-phenylalanine; phenylpyruvate; pyruvate; L-tyrosine ID ESCHERICHIA-COLI; THERMODYNAMICS; ASPARTATE AB Apparent equilibrium constants and calorimetric enthalpies of reaction have been measured for the following enzyme-catalysed biochemical reactions at the temperature 298.15 K: L-alanine(aq)+ 2-oxoglutarate(aq) = pyruvate(aq)+ L-glutamate(aq); L-tyrosine(aq)+ 2-oxoglutarate(aq)= 4-hydroxyphenylpyruvate(aq) + L-glutamate(aq); and L-phenylalanine(aq) + 2-oxoglutarate(aq)= phenylpyruvate(aq)+ L-glutamate(aq). The results are used to calculate equilibrium constants and standard molar enthalpy, entropy, and Gibbs energy changes for reference reactions involving specific species. Apparent equilibrium constants and standard transformed Gibbs energy changes for these reactions under physiological conditions have also been calculated. The results are discussed in terms of the changes in chemical bonding characteristic of transamination reactions. (C) 1998 Academic Press. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Tewari, YB (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 29 TC 14 Z9 14 U1 0 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD JUN PY 1998 VL 30 IS 6 BP 777 EP 793 DI 10.1006/jcht.1998.0342 PG 17 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA ZW883 UT WOS:000074457900012 ER PT J AU Southworth, SH LeBrun, T Azuma, Y Dyall, KG AF Southworth, SH LeBrun, T Azuma, Y Dyall, KG TI Argon KM photoelectron satellites SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE X-ray photoelectron spectroscopy; satellites; inner shell; shake theory ID SYNCHROTRON RADIATION; NONDIPOLAR ASYMMETRIES; SHELL PHOTOIONIZATION; ANGULAR-DISTRIBUTIONS; HIGH-RESOLUTION; CROSS-SECTION; AR K; THRESHOLD; SPECTRA; EDGE AB Satellite structure in the Ar K-shell photoelectron spectrum due to M-shell excitations was recorded at X-ray energies 122-422 eV above threshold. Relativistic, multiconfiguration shake-theory calculations give a good overall match to the main satellite features, showing that electron correlation in this case is qualitatively well described by the relaxation model. Conjugate satellite intensities appear to be negligible at the X-ray energies used in the experiment. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Lab High Energy Phys, Photon Factory, Tsukuba, Ibaraki 305, Japan. NASA, Ames Res Ctr, Thermosci Inst, Moffett Field, CA 94035 USA. RP Southworth, SH (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 37 TC 4 Z9 4 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD JUN PY 1998 VL 94 IS 1-2 BP 33 EP 38 DI 10.1016/S0368-2048(98)00149-2 PG 6 WC Spectroscopy SC Spectroscopy GA 100GB UT WOS:000074806800005 ER PT J AU Amirtharaj, PM Bhat, IB AF Amirtharaj, PM Bhat, IB TI 1997 US Workshop on the Physics and Chemistry of II-VI Materials - Foreword SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Editorial Material C1 NIST, Gaithersburg, MD 20899 USA. Rensselaer Polytech Inst, Troy, NY USA. RP Amirtharaj, PM (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUN PY 1998 VL 27 IS 6 BP 489 EP 489 DI 10.1007/s11664-998-0001-y PG 1 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA ZV637 UT WOS:000074325800001 ER PT J AU Serebrov, AP Kuznetsov, IA Stepanenko, IV Aldushchenkov, AV Lasakov, MS Mostovoi, YA Erozolimskii, BG Dewey, MS Wietfeldt, FE Zimmer, O Borner, H AF Serebrov, AP Kuznetsov, IA Stepanenko, IV Aldushchenkov, AV Lasakov, MS Mostovoi, YA Erozolimskii, BG Dewey, MS Wietfeldt, FE Zimmer, O Borner, H TI Measurement of the antineutrino escape asymmetry with respect to the spin of the decaying neutron SO JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS LA English DT Article ID RIGHT-HANDED CURRENTS; ULTRACOLD NEUTRONS; BETA-DECAY; LIFETIME; POLARIZATION; SEARCH; BOSON AB The result of a new run of measurements of the antineutrino escape asymmetry with respect to the spin of the decaying neutron is presented. The asymmetry coefficient is B = 0.9821 +/- 0.0040, which is consistent with the prediction of the standard model of weak interactions. The prospects for increasing the accuracy of the measurements are discussed. (C) 1998 American Institute of Physics. C1 Russian Acad Sci, BP Konstantinov St Petersburg Nucl Phys Inst, Gatchina 188350, Russia. IV Kurchatov Atom Energy Inst, Moscow 123182, Russia. Harvard Univ, Cambridge, MA 02138 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble 9, France. RP Serebrov, AP (reprint author), Russian Acad Sci, BP Konstantinov St Petersburg Nucl Phys Inst, Gatchina 188350, Russia. RI Serebrov, Anatoly/A-6771-2014 OI Serebrov, Anatoly/0000-0002-6734-038X NR 14 TC 31 Z9 31 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1063-7761 J9 J EXP THEOR PHYS+ JI J. Exp. Theor. Phys. PD JUN PY 1998 VL 86 IS 6 BP 1074 EP 1082 DI 10.1134/1.558574 PG 9 WC Physics, Multidisciplinary SC Physics GA 107XT UT WOS:000075236800003 ER PT J AU Papadopoulos, G Otugen, MV AF Papadopoulos, G Otugen, MV TI A modified Borda-Carnot relation for the prediction of maximum recovery pressure in planar sudden expansions flows SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID BACKWARD-FACING STEP; REATTACHMENT DOWNSTREAM; SHEAR-LAYER C1 Polytech Univ, Brooklyn, NY 11201 USA. RP Papadopoulos, G (reprint author), NIST, B360-224, Gaithersburg, MD 20899 USA. NR 16 TC 1 Z9 1 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD JUN PY 1998 VL 120 IS 2 BP 400 EP 402 DI 10.1115/1.2820662 PG 3 WC Engineering, Mechanical SC Engineering GA ZU129 UT WOS:000074165200024 ER PT J AU Lucas, JR Dillinger, WH AF Lucas, JR Dillinger, WH TI MINQUE for block diagonal bordered systems such as those encountered in VLBI data analysis SO JOURNAL OF GEODESY LA English DT Article DE MINQUE; block-diagonal bordered systems; VLBI AB A sparse matrix method is developed for computing variance factors for block-diagonal, bordered systems of equations using MINQUE (Minimum Norm Quadratic Unbiased Estimation). This method greatly reduces the computational effort required to apply MINQUE, thus making it practical to compute variance factors for some very large systems of equations. The computer implementation of the method is described and applied to the computation of variance factors for a combination of 1609 VLBI (Very Long Baseline Interferometry) observing sessions. The purpose of this test was to compute a variance factor for each of the data sets and, perhaps, to obtain more realistic variance estimates to replace those in common use for the analysis of VLBI data. It was found that the method is satisfactory for use with such large problems, and the test served to verify that the variances in current use in VLBI data adjustments are adequate. C1 NOAA, NOS, NGS, Silver Spring, MD 20910 USA. RP NOAA, NOS, NGS, 1315 East West Highway,8th Fl, Silver Spring, MD 20910 USA. EM billd@dino.grdl.noaa.gov NR 13 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0949-7714 EI 1432-1394 J9 J GEODESY JI J. Geodesy PD JUN PY 1998 VL 72 IS 6 BP 343 EP 349 DI 10.1007/s001900050173 PG 7 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 100HD UT WOS:000074810000003 ER PT J AU Lu, G Baker, DN McPherron, RL Farrugia, CJ Lummerzheim, D Ruohoniemi, JM Rich, FJ Evans, DS Lepping, RP Brittnacher, M Li, X Greenwald, R Sofko, G Villain, J Lester, M Thayer, J Moretto, T Milling, D Troshichev, O Zaitzev, A Odintzov, V Makarov, G Hayashi, K AF Lu, G Baker, DN McPherron, RL Farrugia, CJ Lummerzheim, D Ruohoniemi, JM Rich, FJ Evans, DS Lepping, RP Brittnacher, M Li, X Greenwald, R Sofko, G Villain, J Lester, M Thayer, J Moretto, T Milling, D Troshichev, O Zaitzev, A Odintzov, V Makarov, G Hayashi, K TI Global energy deposition during the January 1997 magnetic cloud event SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID AURORAL ELECTROJET INDEXES; SOLAR-WIND; IONOSPHERIC ELECTRODYNAMICS; GEOMAGNETIC STORM; FIELD; MAGNETOSPHERE; THERMOSPHERE; PARAMETERS; AE AB The passage of an interplanetary magnetic cloud at Earth on January 10-11, 1997, induced significant geomagnetic disturbances, with a maximum AE in excess of 2000 nT and a minimum Dst of about -85 nT. We use a comprehensive set of data collected from space-borne instruments and from ground-based facilities to estimate the energy deposition associated with the three major magnetospheric sinks during the event. It is found that averaged over the 2-day period, the total magnetospheric energy deposition rate is about 400 GW, with 190 GW going into Joule heating rate, 120 GW into ring current injection, and 90 GW into auroral precipitation. By comparison, the average solar wind electromagnetic energy transfer rate as represented by the &EPSILON; parameter is estimated to be 460 GW, and the average available solar wind kinetic power USW is about 11,000 GW. A good linear correlation is found between the AE index and various ionospheric parameters such as the cross-polar-cap potential drop, hemisphere-integrated Joule heating rate, and hemisphere-integrated auroral precipitation. In the northern hemisphere where the data coverage is extensive, the proportionality factor is 0.06 kV/nT between the potential drop and AE, 0.25 GW/nT between Joule heating rate and AE, and 0.13 GW/nT between auroral precipitation and AE. However, different studies have resulted in different proportionality factors. One should therefore be cautious when using empirical formulas to estimate the ionospheric energy deposition. There is an evident saturation of the cross-polar-cap potential drop for large AE(>1000 nT), but further studies are needed to confirm this. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Johns Hopkins Univ, Appl Phys Lab, Baltimore, MD 20742 USA. Phillips Lab, Hanscom AFB, MA 01731 USA. NOAA, Space Environm Ctr, Space Environm Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Dept Geophys, Seattle, WA 98122 USA. Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada. CNRS, Lab Phys & Chim Environm, F-45071 Orleans, France. Univ Leicester, Dept Phys, Leicester LE1 7RH, Leics, England. SRI Int, Menlo Park, CA 94025 USA. Danish Meteorol Inst, Copenhagen, Denmark. York Univ, Dept Phys, York Y01 5DD, N Yorkshire, England. Arctic & Antarctic Res Inst, Dept Geophys, St Petersburg 199226, Russia. IZMIRAN, Troitsk 142092, Moscow Region, Russia. Inst Cosmophys Res & Aeron, Yakutsk, Russia. Univ Tokyo, Dept Earth & Planetary Phys, Tokyo 113, Japan. RP Lu, G (reprint author), Natl Ctr Atmospher Res, High Altitude Observ, POB 3000, Boulder, CO 80307 USA. RI Lu, Gang/A-6669-2011; Moretto, Therese/B-6846-2013 OI Moretto, Therese/0000-0002-2403-5561 NR 30 TC 120 Z9 121 U1 1 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1998 VL 103 IS A6 BP 11685 EP 11694 DI 10.1029/98JA00897 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZQ564 UT WOS:000073880700011 ER PT J AU Giachetti, RE AF Giachetti, RE TI A decision support system for material and manufacturing process selection SO JOURNAL OF INTELLIGENT MANUFACTURING LA English DT Article DE multi-attribute decision making; material selection; process selection; design for manufacturing; concurrent engineering; possibility theory; fuzzy sets; manufacturing processes ID DESIGN AB The material and manufacturing process selection problem is a multi-attribute decisionmaking problem. These decisions are made during the preliminary design stages in an environment characterized by imprecise and uncertain requirements, parameters, and relationships. Material and process selection decisions must occur before design for manufacturing can begin. This paper describes a prototype material and manufacturing process selection system called MAMPS that integrates a formal multi-attribute decision model with a relational database. The decision model enables the representation of the designer's preferences over the decision factors. A compatibility rating between the product profile requirements and the alternatives stored in the database for each decision criteria is generated using possibility theory. The vector of compatibility ratings are aggregated into a single rating of that alternative's compatibility. A ranked set of compatible material and manufacturing process alternatives is output by the system. This approach has advantages over existing systems that either do not have a decision module or Ire not integrated with a database. C1 Natl Inst Stand & Technol, Mfg Syst Integrat Div, Gaithersburg, MD 20899 USA. RP Giachetti, RE (reprint author), Natl Inst Stand & Technol, Mfg Syst Integrat Div, Bldg 304,Rm 12, Gaithersburg, MD 20899 USA. NR 24 TC 42 Z9 45 U1 0 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0956-5515 J9 J INTELL MANUF JI J. Intell. Manuf. PD JUN PY 1998 VL 9 IS 3 BP 265 EP 276 DI 10.1023/A:1008866732609 PG 12 WC Computer Science, Artificial Intelligence; Engineering, Manufacturing SC Computer Science; Engineering GA 110GH UT WOS:000075371500005 ER PT J AU Peterson, W AF Peterson, W TI Life cycle strategies of copepods in coastal upwelling zones SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 6th International Conference on Copepoda CY JUL 29-AUG 03, 1996 CL OLDENBURG, GERMANY DE Copepoda; upwelling zones; advection ID CALANUS-FINMARCHICUS; CALANOIDES-CARINATUS; POPULATION-DYNAMICS; VERTICAL MIGRATION; BENGUELA ECOSYSTEM; MAINTENANCE; CIRCULATION; ZOOPLANKTON; MECHANISMS; MARSHALLAE AB Life cycles of copepods of coastal upwelling zones are of the multigenerational type-as many as 10 or more generations may be produced each year, depending upon water temperature, food concentration and length of the upwelling season. Abundant food resources and moderate temperature convey advantages to those copepods living in coastal upwelling zones, however, there is a clear disadvantage in that coastal upwelling zones are highly advective environments. Typically, water circulation patterns are such that surface waters are carried offshore, deeper waters carried onshore and most of the water column over the continental shelf is moving equatorward. The challenge to copepod species that inhabit upwelling systems is Life cycle closure-how do eggs, nauplii, juveniles and adults avoid being swept out of these ecosystems in the face of persistent transport out of the system? In this review, I first list the species which dominate coastal upwelling ecosystems then discuss three variations on the multigenerational life cycle scheme that are observed in upwelling systems. The latter part of the review is devoted to discussion of how individuals are retained in the productive continental shelf waters within coastal upwelling ecosystems. The suggestion is made that the only copepod species that successfully achieve life cycle closure in such systems are those that are preadapted to upwelling circulation patterns. Our quantitative understanding of the relative importance of physical factors (such as advection) and biological factors (birth, growth, and mortality) on life cycle strategies and population dynamics is quite rudimentary. It would help our understanding if there were more field studies and more computer modeling studies that focused on seasonal cycles of abundance, development times and vertical distribution of life cycle stages, and measurements of water circulation patterns. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Newport, OR 97365 USA. RP Peterson, W (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM bpeterso@sable.nwfsc-hc.noaa.gov NR 44 TC 113 Z9 115 U1 0 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD JUN PY 1998 VL 15 IS 1-4 BP 313 EP 326 DI 10.1016/S0924-7963(97)00082-1 PG 14 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 101NY UT WOS:000074876100036 ER PT J AU Matsuya, S Matsuya, Y Takagi, S Chow, LC AF Matsuya, S Matsuya, Y Takagi, S Chow, LC TI Effect of fluoride on apatite formation from Ca-4(PO4)(2)O in 0.1 mol L-1 KH2PO4 SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE LA English DT Article ID CALCIUM-PHOSPHATE CEMENTS; LOW-TEMPERATURE FORMATION; HYDROXYAPATITE FORMATION; AQUEOUS-SOLUTION; DICALCIUM PHOSPHATE; HYDROLYSIS; KINETICS AB The effect of fluoride on the hydrolysis of tetracalcium phosphate (TTCP; Ca-4(PO4)(2)O) was investigated in 0.1 mol l(-1) KH2PO4 containing 0-83 mol l(-1) KF. Characterization of the final apatite phase formed by the hydrolysis was made with X-ray diffraction and SEM. The initial pH was between 4.5 and 5.4, depending on the solutions, and the pH rapidly increased and was kept constant between 7.3 and 6.5. An increase in KF concentration tended to lower the pH in the final stage of hydrolysis. The calcium concentration was considerably lower than the phosphorus concentration throughout the reaction. The fluoride concentration decreased shortly after the start of hydrolysis. The hydrolysis of TTCP in 0.1 mol l(-1) KH2PO4 proceeded to form hydroxyapatite via DCPD when the KF concentration was low. The hydrolysis product was a calcium-deficient non-stoichiometric hydroxyapatite with a Ca/P ratio of about 1.5. With an increase in the KF concentration in the 0.1 mol l(-1) KH2PO4 solution, TTCP directly transformed into hydroxyapatite containing F- ions or fluorapatite and with improved crystallinity. The addition of fluoride in the solution initially accelerated the formation of apatite. However, the layer of newly formed apatite adhering to the TTCP particles retarded TTCP dissolution; as a result, hydrolysis was delayed. IR analysis showed that the apatite phase contained HPO42- ions in the structure. The formula for the hydrolysis product of TTCP in the presence of fluoride can be expressed as follows: Ca10-x(HPO4)(x)(PO4)(10-x)(OH)(2-x-y)F-y. C1 Kyushu Univ, Fac Dent, Dept Dent Mat Engn, Fukuoka 81282, Japan. Kyushu Univ, Fac Dent, Dept Operat Dent & Endodontol, Fukuoka 81282, Japan. Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Matsuya, S (reprint author), Kyushu Univ, Fac Dent, Dept Dent Mat Engn, Fukuoka 81282, Japan. NR 26 TC 14 Z9 14 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0957-4530 J9 J MATER SCI-MATER M JI J. Mater. Sci.-Mater. Med. PD JUN PY 1998 VL 9 IS 6 BP 325 EP 331 DI 10.1023/A:1008850829768 PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 102HH UT WOS:000074918000004 PM 15348875 ER PT J AU Heyliger, P Ledbetter, H AF Heyliger, P Ledbetter, H TI Detection of surface and subsurface flaws in homogeneous and composite solids by resonant ultrasound SO JOURNAL OF NONDESTRUCTIVE EVALUATION LA English DT Article DE resonant ultrasound; surface crack; finite element method; bond flaw ID ELASTIC-CONSTANTS AB We used resonant ultrasound spectroscopy (RUS) to detect two types of flaws: a surface crack in a steel block and an interior void in a bilayered composite block. Detection is possible because cracks alter an object's macroscopic vibration frequencies, which can be measured to better than 1 Hz in 1 MHz. The surface crack decreased the resonant frequencies up to 50%. The interior flaw in the adhesive joint between an aluminum alloy and a graphite-epoxy layer, increased resonant frequencies with increasing flaw size. We confirmed our measurements with finite-element and Ritz approximation calculations. Our study supports the use of RUS to detect cracks. C1 Colorado State Univ, Dept Civil Engn, Ft Collins, CO 80523 USA. Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. RP Heyliger, P (reprint author), Colorado State Univ, Dept Civil Engn, Ft Collins, CO 80523 USA. NR 11 TC 8 Z9 8 U1 1 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9298 J9 J NONDESTRUCT EVAL JI J. Nondestruct. Eval. PD JUN PY 1998 VL 17 IS 2 BP 79 EP 87 DI 10.1007/BF02995485 PG 9 WC Materials Science, Characterization & Testing SC Materials Science GA 116UZ UT WOS:000075744500004 ER PT J AU Clark, AV Schaps, SR AF Clark, AV Schaps, SR TI Acoustoelastic determination of residual stress by measurement of resonance peaks and phase shifts SO JOURNAL OF NONDESTRUCTIVE EVALUATION LA English DT Article DE acoustoelasticity; EMATs; resonance; stress ID VELOCITIES; TEXTURE AB We made ultrasonic measurements of residual stress in a well-characterized specimen: an aluminum shrink-fit plate. We used various electromagnetic-acoustic transducers (EMATs) to generate and receive both shear and longitudinal waves. From the difference of velocities of orthogonally polarized shear waves (acoustic birefringence) we obtained the difference of principal stresses. From ratios of velocities of longitudinal and shear waves we obtained the sum of principal stresses. From the sum and difference we determined the principal stresses and found good agreement with theory. To obtain our ultrasonic data, we used two different techniques: measurement of resonant frequencies and phase shifts. We compared these methods both for accuracy and ease of implementation. For our experiments, phase shift measurements were superior. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Gaithersburg, MD 20899 USA. RP Clark, AV (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, Gaithersburg, MD 20899 USA. NR 22 TC 5 Z9 5 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9298 J9 J NONDESTRUCT EVAL JI J. Nondestruct. Eval. PD JUN PY 1998 VL 17 IS 2 BP 89 EP 102 DI 10.1007/BF02995486 PG 14 WC Materials Science, Characterization & Testing SC Materials Science GA 116UZ UT WOS:000075744500005 ER PT J AU Ghosh, P Patterson, GW Wikfors, GH AF Ghosh, P Patterson, GW Wikfors, GH TI Sterols of some marine Prymnesiophyceae SO JOURNAL OF PHYCOLOGY LA English DT Article DE 24-ethylcholest-22-enol; 24-ethylcholesta-5,22-dienol; 24-methylcholesta-5,22-dienol; cholesterol; dihydroxysterols; Ochrosphaera; Pavlova; pavlovol; Pleurochrysis; Prymnesiophyceae; Prymnesium; sterol ID CRASSOSTREA-VIRGINICA; FATTY-ACID; PAVLOVA; PHYTOPLANKTON; OYSTERS AB Sterols were identified in six marine prymnesiophyte isolates, some of which appear to have value as bivalve food. The principal sterol in Pleurochrysis carterae (Milford #961) and an unidentified prymnesiophyte (CCMP1215) was 24-methylcholesta-5,22-dienol, a common sterol in prymnesiophytes. Isolates CCMP594, CCMP609, and CCMP459 contained either 24-ethylcholesta-5,22-dienol or 24-ethylcholest-22-enol as the major sterol. In addition, Pavlova pinguis (CCMP609) and Pavlova sp. (CCMP459) contained the unusual dihydroxysterols 24-methylpavlovol and 24-ethylpavlovol, which have been found only in members of the Pavlovalves. Prymnesium parvum contained cholesterol without traces of other sterols. Compared to the other isolates, the quantity of sterols was extremely low in P. parvum. C1 Univ Maryland, Dept Plant Biol, College Pk, MD 20742 USA. Natl Marine Fisheries Serv, NOAA, NW Fisheries Sci Ctr, Milford, CT 06460 USA. RP Patterson, GW (reprint author), Univ Maryland, Dept Plant Biol, College Pk, MD 20742 USA. NR 22 TC 14 Z9 20 U1 3 U2 12 PU PHYCOLOGICAL SOC AMER INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD JUN PY 1998 VL 34 IS 3 BP 511 EP 514 DI 10.1046/j.1529-8817.1998.340511.x PG 4 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA ZZ445 UT WOS:000074730100013 ER PT J AU White, WB Chao, Y Tai, CK AF White, WB Chao, Y Tai, CK TI Coupling of biennial oceanic Rossby waves with the overlying atmosphere in the Pacific basin SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID TROPICAL NORTH PACIFIC; SEA-SURFACE TEMPERATURE; NINO SOUTHERN OSCILLATION; TERM CLIMATIC VARIABILITY; EL-NINO; TOPEX/POSEIDON DATA; BAROCLINIC WAVES; ANOMALIES; GENERATION; FREQUENCY AB Anomalies of TOPEX/Poseidon sea level height (SLH). NCEP sea surface temperature (SST), and ECMWF meridional surface wind (MSW) and derived wind stress curl (WSC) are mapped biweekly over the global ocean from 60 degrees S to 60 degrees N for two years from 1993 to 1994. These anomalies (i.e., differences from the average over the two years) allow one cycle of biennial climate change to be examined, with the paucity of temporal degrees of freedom mitigated by greater numbers of spatial degrees of freedom. Time-longitude diagrams of SLH anomalies reveal biennial Rossby waves in the Pacific ocean with westward phase speeds in the extratropics (Tropics) faster (slower) than expected of free biennial Rossby waves. Complex empirical orthogonal function analysis of SLH, SST, MSW, and WSC anomalies finds the beta-refraction pattern of these biennial Rossby waves in all four variables over most of the eastern-central Pacific Ocean, suggesting that oceanic Rossby waves there are coupled with the overlying atmosphere. The spatial phase relationship between SLH and SST anomaly patterns is consistent with an upper-ocean heat budget where the anomalous meridional heat advection by geostrophic flows associated with biennial Rossby waves is balanced by anomalous heat loss to the atmosphere. The spatial phase relationship between SST and MSW anomaly patterns is consistent with lower-tropospheric heat and vorticity budgets, where MSW anomalies arise from a balance between planetary vorticity advection and SST-induced low-level convergence. Using these basic heat and vorticity balances for upper ocean and lower troposphere, an analytic coupled model is constructed where the subsequent feedback by WSC anomalies upon the Free biennial Rossby waves (via Ekman pumping) is found to be positive, causing wave amplitudes to grow ol be maintained against dissipation, and producing westward phase speeds faster (slower) than expected of the free Rossby wave speeds in the extratropics (Tropics), as observed. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NOAA, Natl Ocean Serv, Silver Spring, MD USA. RP White, WB (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, 95 Gilman Dr, La Jolla, CA 92093 USA. EM wbwhite@ucsd.edu RI Tai, C.K./F-5628-2010 NR 41 TC 39 Z9 41 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1998 VL 28 IS 6 BP 1236 EP 1251 DI 10.1175/1520-0485(1998)028<1236:COBORW>2.0.CO;2 PG 16 WC Oceanography SC Oceanography GA ZU133 UT WOS:000074165600012 ER PT J AU Tolman, HL Bender, LC Neu, WL AF Tolman, HL Bender, LC Neu, WL TI Comments on "The Goddard coastal wave model. Part I: Numerical method" SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Editorial Material ID UNSTEADY; PHYSICS C1 NOAA, NCEP, Environm Modeling Ctr, Ocean Modeling Branch, Camp Springs, MD 20746 USA. Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. Virginia Tech, Dept Aerosp & Ocean Engn, Blacksburg, VA USA. RP NOAA, NCEP, Environm Modeling Ctr, Ocean Modeling Branch, 5200 Auth Rd,Room 209, Camp Springs, MD 20746 USA. EM Hendrik.Tolman@NOAA.gov NR 18 TC 3 Z9 3 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 EI 1520-0485 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1998 VL 28 IS 6 BP 1287 EP 1290 DI 10.1175/1520-0485(1998)028<1287:COTGCW>2.0.CO;2 PG 4 WC Oceanography SC Oceanography GA ZU133 UT WOS:000074165600015 ER PT J AU Tolman, HL Neu, WL Bender, LC AF Tolman, HL Neu, WL Bender, LC TI Comments on "The Goddard Coastal Wave Model. Part II: Kinematics" SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Editorial Material ID WIND-WAVES; UNSTEADY; CURRENTS; DEPTHS; TIDES C1 NOAA, NCEP, Environm Modelling Ctr, Ocean Modeling Branch, Camp Springs, MD 20746 USA. Virginia Tech, Dept Aerosp & Ocean Engn, Blacksburg, VA USA. Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. RP Tolman, HL (reprint author), NOAA, NCEP, Environm Modelling Ctr, Ocean Modeling Branch, 5200 Auth Rd,Room 209, Camp Springs, MD 20746 USA. EM Hendrik.Tolman@NOAA.gov NR 17 TC 1 Z9 1 U1 2 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1998 VL 28 IS 6 BP 1305 EP 1308 DI 10.1175/1520-0485(1998)028<1305:COTGCW>2.0.CO;2 PG 4 WC Oceanography SC Oceanography GA ZU133 UT WOS:000074165600017 ER PT J AU Clerc, DG Ledbetter, HM AF Clerc, DG Ledbetter, HM TI Mechanical hardness: A semiempirical theory based on screened electrostatics and elastic smear SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE ceramics; metals; elastic properties; mechanical properties ID BORON-NITRIDE; BULK MODULI; CONSTANTS; SOLIDS; PARAMETER; CRYSTALS AB The equation H = AGh(s) is the first to describe the mechanical hardness H of materials having arbitrary crystal structure or bonding type, where A is a constant, G is the isotropic elastic shear modulus, and h(s) is a scaling relation for the chemical hardness of an indented solid. Here, h(s) is deemed to be the second derivative of the total electronic energy with respect to the electron population of atoms in the indented region of the solid. From this definition and semiempirical arguments, h(s) is a simple function of those atoms' effective nuclear charge Z(eff) and the number of nearest neighbors to the most electronegative atom in the perfect crystal, The model equation is used to calculate the hardness of 71 materials, having assorted crystal structures and bonding types, that are (A) I-atom or 2-atom nonmetals or (B) simple metals. The class-A calculated hardnesses lie within 20% (30%) of experiment for 77% (92%) of the materials. The class-B calculated hardnesses lie within 20% (30%) of experiment for 42% (61%) of the simple metals. The results enable mechanical hardness to be calculated solely in terms of the crystal structure geometry and intrinsic atomic-level properties Z(eff) and G, where G is obtained from monocrystal elastic constants using quasiisotropic polycrystalline bounding equations. Consequently, hardness may be estimated for proposed superhard ceramic materials by coupling the model equation with ab initio solid-state electronic structure calculations of the elastic constants. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Clerc, DG (reprint author), TJ Technol Inc, 3850 Res Pk Dr,POB 2150, Ann Arbor, MI 48106 USA. NR 44 TC 77 Z9 81 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD JUN-JUL PY 1998 VL 59 IS 6-7 BP 1071 EP 1095 DI 10.1016/S0022-3697(97)00251-5 PG 25 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 102FZ UT WOS:000074914900031 ER PT J AU Siefert, DLW AF Siefert, DLW TI Distinguishing between Stage I and Stage II nauplii of the copepods Metridia and Pseudocalanus from the Bering Sea SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID POLLOCK THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; FEEDING ECOLOGY; LIFE-HISTORIES; FUNKA BAY; LARVAE; HOKKAIDO; PACIFIC; ALASKA; JAPAN AB Stage I nauplii of Metridia pacifica, Stage I and II nauplii of Metridia lucens, and the equivalent stages of Pseudocalanus mimus were reared from eggs to find morphological characters for separating the genera at these stages. Differences in naupliar body shape and caudal armature permit the differentiation of Stage I and II Metridia from Pseudocalanus in southeastern Bering Sea plankton. C1 NOAA, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Siefert, DLW (reprint author), NOAA, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE,BIN C15700, Seattle, WA 98115 USA. NR 32 TC 2 Z9 2 U1 1 U2 5 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 J9 J PLANKTON RES JI J. Plankton Res. PD JUN PY 1998 VL 20 IS 6 BP 1061 EP 1072 DI 10.1093/plankt/20.6.1061 PG 12 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA ZX408 UT WOS:000074512800003 ER PT J AU Chance, KV Park, K Evenson, KM AF Chance, KV Park, K Evenson, KM TI Pressure broadening of far infrared rotational transitions: 88.65 CM-1 H2O and 114.47 CM-1 O-3 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID DATABASE; N2; O2 AB We measured N-2 and O-2 pressure broadening coefficients for the 88.65 cm(-1) line of H2O at 290 K and the 114.47 cm(-1) line of O-3 at 290 and 210 K. Broadening measurements of these lines also include determinations of the self broadening and a frequency measurements of the transitions. Published by Elsevier Science Ltd. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Park, K (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1998 VL 59 IS 6 BP 687 EP 688 DI 10.1016/S0022-4073(97)00153-2 PG 2 WC Optics; Spectroscopy SC Optics; Spectroscopy GA ZG314 UT WOS:000072988900010 ER PT J AU Lawn, BR Lee, SK Peterson, IM Wuttiphan, S AF Lawn, BR Lee, SK Peterson, IM Wuttiphan, S TI Model of strength degradation from Hertzian contact damage in tough ceramics SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID HETEROGENEOUS GRAIN-STRUCTURE; SILICON-CARBIDE; INDENTATION FRACTURE; BRITTLE SOLIDS; CRACK-GROWTH; COMPRESSION; FATIGUE; DUCTILE; FAILURE; MECHANICS AB A model of strength degradation for ceramics subject to damage from contact with hard spheres is developed. Primary attention is focused on tough ceramics with heterogeneous microstructures which deform in a quasi-plastic mode. Brief consideration is also given to ideally brittle ceramics which form classical ring cracks, as a comparative baseline. Strength vs indentation load data from two microstructurally controlled ceramics, silicon nitride and a micaceous glass-ceramic, illustrate distinctive strength degradation responses: in fine-grain (F) form, ideally brittle failure from ring cracks, with abrupt strength loss at the critical load for crack initiation followed by a slow falloff at increasing load; in coarse-grain (C) form, failure from within the quasi-plastic zone, with continuous strength loss beyond a load well above that for the onset of yield, and with even slower falloff. Failure in the latter materials occurs from contact-induced microdamage flaws with two essential elements: an inner closed shear crack with frictional sliding faces ("shear fault"), which forms within the confining compression-sheer contact field; an outer annular, kinked crack that initiates at the fault edges ("wing crack"), and that extends in tensile local mode. The critical fault-crack is modeled as a virtual crack, with the residual field from the inner fault stabilizing the net driving force on the outer wing crack during ensuing tensile loading. Finite element modeling is used to evaluate the nonlinear elastic-plastic contact fields, and to provide a relationship between residual shear fault stress and contact load. The model accounts for the essential qualitative and quantitative features of the strength-load data, with provision for catastrophic degradation at high fault densities and extreme loads by microcrack coalescence. The model also contains the ingredients for analysis of contact fatigue, via attrition of the frictional tractions on the residual fault. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 51 TC 46 Z9 48 U1 1 U2 13 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 1998 VL 81 IS 6 BP 1509 EP 1520 PG 12 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600014 ER PT J AU Farber, L Barsoum, MW Zavaliangos, A El-Raghy, T Levin, I AF Farber, L Barsoum, MW Zavaliangos, A El-Raghy, T Levin, I TI Dislocations and stacking faults in Ti3SiC2 SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article AB The ternary carbide Ti3SIC2 fabricated by a reactive hot-press route is investigated by transmission electron microscopy. The material consists mainly of large elongated grains with planar boundaries, and is characterized by a low defect density. Dislocations are observed in the grains and at grain boundaries. Perfect dislocations with b = 1/3 [11(2) over bar 0] lying in (0001) basal planes are present. These basal plane dislocations are mobile and multiply as a result of room-temperature deformation. All of the stacking faults observed lie in the basal planes. C1 Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Farber, L (reprint author), Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. RI Levin, Igor/F-8588-2010; Zavaliangos, Antonios/B-6238-2012 NR 11 TC 71 Z9 73 U1 0 U2 9 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD JUN PY 1998 VL 81 IS 6 BP 1677 EP 1681 PG 5 WC Materials Science, Ceramics SC Materials Science GA ZV175 UT WOS:000074277600036 ER PT J AU Qu, WQ Henderson-Sellers, A Pitman, AJ Chen, TH Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Dickinson, RE Dumenil, L Ek, M Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Yang, ZL Zeng, Q AF Qu, WQ Henderson-Sellers, A Pitman, AJ Chen, TH Abramopoulos, F Boone, A Chang, S Chen, F Dai, Y Dickinson, RE Dumenil, L Ek, M Gedney, N Gusev, YM Kim, J Koster, R Kowalczyk, EA Lean, J Lettenmaier, D Liang, X Mahfouf, JF Mengelkamp, HT Mitchell, K Nasonova, ON Noilhan, J Robock, A Rosenzweig, C Schaake, J Schlosser, CA Schulz, JP Shmakin, AB Verseghy, DL Wetzel, P Wood, EF Yang, ZL Zeng, Q TI Sensitivity of latent heat flux from PILPS land-surface schemes to perturbations of surface air temperature SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODELS; CLIMATE FEEDBACK PROCESSES; SOIL-MOISTURE; BOUNDARY-LAYER; PARAMETERIZATION; EVAPORATION; HYDROLOGY; BIOSPHERE; GCMS AB In the PILPS Phase 2a experiment, 23 land-surface schemes were compared in an off-line control experiment using observed meteorological data from Cabauw, the Netherlands. Two simple sensitivity experiments were also undertaken in which the observed surface air temperature was artificially increased or decreased by 2 K while all other factors remained as observed. On the annual timescale, all schemes show similar responses to these perturbations in latent, sensible heat flux, and other key variables. For the 2-K increase in temperature, surface temperatures and latent heat fluxes all increase while net radiation, sensible heat fluxes, and soil moistures all decrease. The results are reversed for a 2-K temperature decrease. The changes in sensible heat fluxes and, especially, the changes in the latent heat fluxes are nor linearly related to the change of temperature. Theoretically, the nonlinear relationship between air temperature and the latent heat flux is evident and due to the convex relationship between air temperature and saturation vapor pressure. A simple test shows that, the effect of the change of air temperature on the atmospheric stratification aside, this nonlinear relationship is shown in the form that the increase of the latent heat flux for a 2-K temperature increase is larger than its decrease for a 2-K temperature decrease. However, the results from the Cabauw sensitivity experiments show that the increase of the latent heat flux in the +2-K experiment is smaller than the decrease of the latent heat flux in the -2-K experiment (we refer to this as the asymmetry). The analysis in this paper shows that this inconsistency between the theoretical relationship and the Cabauw sensitivity experiments results (or the asymmetry) is due to (i) the involvement of the beta(g), formulation, which is a function of a series stress factors that limited the evaporation and whose values change in the +/-2-K experiments, leading to strong modifications of the latent heat flux; (ii) the change of the drag coefficient induced by the changes in stratification due to the imposed air temperature changes (+/-2 K) in parameterizations of latent heat flux common in current land-surface schemes. Among all stress factors involved in the beta(g), formulation, the soil moisture stress in the +2-K experiment induced by the increased evaporation is the main factor that contributes to the asymmetry. C1 RMIT Univ, Dept Math, Melbourne, Vic 3001, Australia. Macquarie Univ, Sch Earth Sci, Sydney, NSW 2109, Australia. Sci Syst & Applicat Inc, Sydney, NSW, Australia. NASA, Goddard Space Flight Ctr, Mesoscale Dynam & Precipitat Branch, Greenbelt, MD 20771 USA. Philips Labs, GPAB, PL, Hanscom AFB, MA USA. NOAA, Natl Ctr Environm Predict, Dev Div, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. Max Planck Inst Meteorol, Hamburg, Germany. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Reading, Dept Meteorol, Reading, Berks, England. Russian Acad Sci, Inst Water Problems, Moscow, Russia. Lawrence Livermore Natl Lab, Livermore, CA USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. Meteorol Off, Hadley Ctr Climate Predict & Res, Bracknell, Berks, England. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. ECMWF, Reading, Berks, England. GKSS, Res Ctr, Dept Phys, Geesthacht, Germany. Meteo France, CNRM, Toulouse, France. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Russian Acad Sci, Inst Geog, Moscow, Russia. Atmospher Environm Serv, Climate Res Branch, Downsview, ON, Canada. Australian Oceanog Data Ctr, Sydney, NSW, Australia. RP Qu, WQ (reprint author), RMIT Univ, Dept Math, GPO Box 2476V, Melbourne, Vic 3001, Australia. EM rmawq@gauss.ma.rmit.edu.au RI Yang, Zong-Liang/B-4916-2011; Pitman, Andrew/A-7353-2011; Henderson-Sellers, Ann/H-5323-2011; Koster, Randal/F-5881-2012; Chen, Fei/B-1747-2009; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; gusev, yugeniy/G-4711-2014; Robock, Alan/B-6385-2016; Dai, Yongjiu/D-6261-2014; OI Pitman, Andrew/0000-0003-0604-3274; Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; gusev, yugeniy/0000-0003-3886-2143; Dai, Yongjiu/0000-0002-3588-6644; Wood, Eric/0000-0001-7037-9675 NR 48 TC 32 Z9 36 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1998 VL 55 IS 11 BP 1909 EP 1927 DI 10.1175/1520-0469(1998)055<1909:SOLHFF>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZT491 UT WOS:000074093200001 ER PT J AU Platt, CMR Young, SA Manson, PJ Patterson, GR Marsden, SC Austin, RT Churnside, JH AF Platt, CMR Young, SA Manson, PJ Patterson, GR Marsden, SC Austin, RT Churnside, JH TI The optical properties of equatorial cirrus from observations in the ARM Pilot Radiation Observation Experiment SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID HIGH CLOUDS; ICE CRYSTALS; BACKSCATTER PROFILES; TROPICAL PACIFIC; CLIMATE FEEDBACK; LIGHT-SCATTERING; LIDAR; TEMPERATURE; EXTINCTION; ABSORPTION AB The optical properties of equatorial cirrus were studied during a three-week period of the ARM Pilot Radiation and Observation Experiment at Kavieng, Papua New Guinea, in January and February 1993. The experiment consisted of vertical lidar (532 nm) and passive infrared filter radiometer (10.84 mu m) observations of cirrus clouds. The observations gave values of cloud height, depth, structure, infrared emittance, infrared absorption, and visible optical depth and linear depolarization ratio. A standard lidar-radiometer analysis, with some improvements, was used to calculate these quantities.;The cirrus was found to vary in altitude from a maximum cloud top of 17.6 km to a minimum cloud base of 6 km with equivalent temperatures of -82 degrees C to -7 degrees C respectively. The cirrus also varied widely in depth (0.7 to 7.5 km). The mean emittance (for each temperature interval) of the cooler clouds was found to be higher than that observed previously at tropical and midlatitude sites and at equivalent temperatures. The mean infrared absorption coefficients were similar to those of midlatitude clouds, except at the extreme temperature ranges, but were higher than those observed in tropical synoptic clouds over Darwin. Infrared optical depths varied from 0.01 to 2.4 and visible optical depths from 0.01 to 8.6. Plots of integrated attenuated backscatter versus infrared emittance, for various ranges of cloud temperature, showed characteristic behavior. Values of the measured quantity k/2 eta, where k is the visible backscatter to extinction ratio and eta a multiple scattering fatter, were found to increase with temperature from 0.14 at -70 degrees C to 0.30 at -20 degrees C. Values of the quantity 2 alpha eta, where alpha is the ratio of visible extinction to infrared absorption coefficient, varied from about 1.7 to 3.8, depending somewhat on the cloud temperature. Deduced values of alpha were as high as 5.3 at the lower temperature ranges; indicating smaller particles. The lidar integrated attenuated depolarization ratio Delta decreased with temperature, as found previously in midlatitude cirrus. Values of Delta varied from 0.42 at -70 degrees C to 0.18 at -10 degrees C. Data obtained from the NOAA/ETL microwave radiometer gave values of water path, varying from 4 to 6 cm precipitable water. A value of the water vapor continuum absorption coefficient at 10.84 mu m equal to 9.0 +/- 0.5 g(-1) cm(2) atm(-1) was obtained in agreement with previous observations. C1 CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. NOAA, ETL, Boulder, CO USA. RP Platt, CMR (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. EM martin@atmos.colostate.edu RI Young, Stuart/A-8641-2011; Churnside, James/H-4873-2013 OI Young, Stuart/0000-0001-6434-9816; NR 49 TC 63 Z9 65 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1998 VL 55 IS 11 BP 1977 EP 1996 DI 10.1175/1520-0469(1998)055<1977:TOPOEC>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZT491 UT WOS:000074093200006 ER PT J AU Ohno, Y AF Ohno, Y TI High illuminance calibration facility and procedures SO JOURNAL OF THE ILLUMINATING ENGINEERING SOCIETY LA English DT Article AB The range of calibration of illuminance and luminance meters has been normally limited to levels up to several thousand lux and several thousand cd/m(2) using a high-power luminous intensity standard lamp. The calibration of instruments at much higherlevels is required in applications such as daylight measurement, evaluation of solar simulators, and testing light sources in imaging devices. A calibration facility and procedures have been develped at NIST utilizing the detector-based method to allow illuminace calibrations at levels up to 100 klx (about the level of direct sunlight) and luminance up to 30 kcd/m(2). The calibration source is based on a commercial solar simulator source using a 1000 W xenon are lamp with optical feedback control, and it is combined with a set of color glass filters that corrects the spectral power distribution to be close to CIE Illuminant A. The illuminance level can be varied without changing the color temperature significantly and without changing the distance. The developed source was evaluated for stability, spectral distribution, illuminance uniformity, and divergence of the beam. Experiments were also conducted to study the effect of heat by radiation on the glass filters used with the source and various diffuser materials, such as PTFE, opal glass, and acrylic used to create luminance standards. The linearity and the effect of heat on standard photometers and commercial illuminance meters were also investigated and appropriate procedures for high illuminance/luminance calibrations have been established. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Ohno, Y (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 6 TC 3 Z9 3 U1 0 U2 1 PU ILLUMINAT ENG SOC NORTH AMER PI NEW YORK PA 120 WALL ST, 17TH FL, NEW YORK, NY 10005-4001 USA SN 0099-4480 J9 J ILLUM ENG SOC JI J. Illum. Eng. Soc. PD SUM PY 1998 VL 27 IS 2 BP 132 EP + PG 9 WC Optics SC Optics GA 108FW UT WOS:000075256300062 ER PT J AU Liu, AS AF Liu, AS TI Self-consistent theory of optical gain with and without inversion in semiconductor quantum wells SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; INTERSUBBAND ABSORPTION; POPULATION-INVERSION; FIELD; COHERENCE; FORMALISM; LASERS AB In a self-consistent field formalism we investigated the weak-probe optical intersubband response of a three-subband semiconductor quantum well pumped by a strong coherent laser beam. We showed that, when the pumping photon energy is somewhat above the energy separation between the two lowest subbands, a combination of hole-burning effects and coherent pump-probe wave interactions can lead to both optical gain without population inversion and an Autler-Townes-like doublet in the probe optical spectrum. These two absorption peaks, whose positions are blueshifted as the pump intensity is increased, are due to the two-photon absorption process and light-induced inter subband transitions between the two upper states. It is also demonstrated that, in a stepwise two-photon pumping scheme, the optical gain with population inversion can also occur in the quantum-well system when a modestly strong pump field is present. (C) 1998 Optical Society of America. C1 Univ Aalborg, Inst Phys, DK-9220 Aalborg, Denmark. RP Liu, AS (reprint author), NIST, Atom Phys Div, Gaithersburg, MD 20899 USA. NR 22 TC 5 Z9 5 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 1998 VL 15 IS 6 BP 1741 EP 1748 DI 10.1364/JOSAB.15.001741 PG 8 WC Optics SC Optics GA ZT289 UT WOS:000074069600016 ER PT J AU Rizi, RR Dimitrov, IE Thompson, A Jones, G Gentile, TR Ishii, M Reddy, R Schnall, MD Leigh, JS AF Rizi, RR Dimitrov, IE Thompson, A Jones, G Gentile, TR Ishii, M Reddy, R Schnall, MD Leigh, JS TI MRI of hyperpolarized He-3 gas in human paranasal sinuses SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE hyperpolarized gas; He-3; paranasal sinuses; MRI ID XE-129 MR; VENTILATION AB In this study, MRI of hyperpolarized He-3 gas in human paranasal sinuses is presented, Helium images were obtained at 1.5 T, using a surface coil and a 2D, fast gradient-echo sequence with a nominal constant flip angle of 12 degrees, Coronal images of 20-mm thick slices were generated and compared with proton images of the corresponding sections. The images enable visualization of the paranasal sinuses and the nasal cavity, suggesting a potential use of this method not only in identifying the anatomical configuration of these pneumatic spaces, but also in assessing sinus ventilation. C1 Univ Penn, Dept Radiol, MMRRCC, Stellar Chance Labs B 1, Philadelphia, PA 19104 USA. Univ Penn, Dept Biophys, Philadelphia, PA 19104 USA. Univ Penn, Dept Otorhinolaryngol Head & Neck Surg, Philadelphia, PA 19104 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Rizi, RR (reprint author), Univ Penn, Dept Radiol, MMRRCC, Stellar Chance Labs B 1, 422 Curie Blvd, Philadelphia, PA 19104 USA. RI Schnall, Mitchell/D-1149-2009; OI Reddy, Ravinder/0000-0003-4580-2392 FU NCRR NIH HHS [RR02305] NR 18 TC 18 Z9 18 U1 0 U2 1 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn.Reson.Med. PD JUN PY 1998 VL 39 IS 6 BP 865 EP 868 DI 10.1002/mrm.1910390603 PG 4 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA ZP499 UT WOS:000073759600003 PM 9621909 ER PT J AU Hanson, MB Baird, RW AF Hanson, MB Baird, RW TI Dall's porpoise reactions to tagging attempts using a remotely-deployed suction-cup tag SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article ID DIVING BEHAVIOR; WILD; DOLPHINS; OCEAN AB Remotely-deployable non-invasive (suction-cup attached) tags to record underwater behavior of cetaceans have recently been developed. How useful these tags are for applications on a broad range of species has yet to be documented. However we attempted to use such tags to study the diving behavior of Dall's porpoise (Phocoenoides dalli) in the trans-boundary area of British Columbia and Washington state, and report here on the feasibility of the technique, including the reactions of Dall's porpoise to tagging attempts. Tagging activities were undertaken in August 1996, while porpoises were bow-riding on a small vessel. We made 15 tagging attempts and 13 resulted in tag contact with a porpoise. No reactions were observed for the 2 misses, nor for 2 of the 13 hits. Of the 11 cases when tag reactions were observed, porpoises returned to continue bow-riding almost immediately in 7 cases, suggesting no long-term effect. Short-term reactions observed included a flinch (9 of 13 hits), tail-slap (1 of 13 hits) and high speed swimming away from the vessel (4 of 13 hits), with some hits resulting in more than one type of reaction. Three of 13 hits resulted in successful tag attachment. One tag remained attached for 41 minutes, providing the first diving behavior data for this species. Rates of descent and ascent, as well as swimming velocity, were relatively high only for the first 6-8 minutes after tag attachment, suggesting a. reaction to tagging that lasted approximately 8 minutes. C1 Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Seattle, WA USA. Dalhousie Univ, Dept Biol, Halifax, NS, Canada. RP Hanson, MB (reprint author), Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Seattle, WA USA. NR 17 TC 16 Z9 16 U1 0 U2 4 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 1998 VL 32 IS 2 BP 18 EP 23 PG 6 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 122LK UT WOS:000076072900002 ER PT J AU Baker, DJ AF Baker, DJ TI Doherty Lecture - Ocean partnerships: A vision for the future SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article C1 US Dept Commerce, NOAA, Under Secretary Oceans & Atmosphere & Administrat, Washington, DC 20230 USA. RP Baker, DJ (reprint author), US Dept Commerce, NOAA, Under Secretary Oceans & Atmosphere & Administrat, Washington, DC 20230 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 1998 VL 32 IS 2 BP 63 EP 71 PG 9 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 122LK UT WOS:000076072900008 ER PT J AU Quenard, DA Xu, K Kunzel, HM Bentz, DP Martys, NS AF Quenard, DA Xu, K Kunzel, HM Bentz, DP Martys, NS TI Microstructure and transport properties of porous building materials SO MATERIALS AND STRUCTURES LA English DT Article ID ELECTRICAL-CONDUCTIVITY; PERMEABILITY; PREDICTION; CEMENT; MEDIA; ROCK AB To successfully predict the performance of building materials exposed to a degradative environment, transport properties must be either measured or estimated. The development of relationships between microstructure and transport properties for these materials should allow accurate prediction of the latter and an increased understanding of how microstructure influences transport. Here, two microstructural characterization techniques, mercury intrusion porosimetry and scanning electron microscopy, are combined with computer modelling techniques to compute the vapor diffusivity and air permeability of three building materials commonly exposed in building facades, two types of brick and a natural sandstone. In general, the computed values compare favorably to those measured experimentally, thus demonstrating the capability of employing microstructural characterization to predict transport properties. C1 Ctr Sci & Tech Batiment, Serv Mat, F-38400 St Martin Dheres, France. Fraunhofer Inst Bauphys, D-83601 Holzkirchen, Germany. NIST, Bldg Mat Div, Bldg & Fire Res Lab, US Dept Commerce, Gaithersburg, MD 20899 USA. RP Quenard, DA (reprint author), Ctr Sci & Tech Batiment, Serv Mat, 24 Rue Joseph Fourier, F-38400 St Martin Dheres, France. NR 20 TC 28 Z9 29 U1 2 U2 4 PU R I L E M PI CACHAN PA PAVILLON DES JARDINS, 61 AV DU PRESIDENT WILSON, 94235 CACHAN, FRANCE SN 0025-5432 J9 MATER STRUCT JI Mater. Struct. PD JUN PY 1998 VL 31 IS 209 BP 317 EP 324 DI 10.1007/BF02480673 PG 8 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA ZU491 UT WOS:000074203400005 ER PT J AU Prendergast, J Foley, N Suehle, JS AF Prendergast, J Foley, N Suehle, JS TI Investigation of the intrinsic SiO2 area dependence using TDDB testing and model integration into the design process SO MICROELECTRONICS AND RELIABILITY LA English DT Article; Proceedings Paper CT 9th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis (ESREF 98) CY 1998 CL COPENHAGEN, DENMARK AB This paper models the area dependency for thin SiO2 films (1.2E-7 to 1E-2 cm(2)) using Time Dependent Dielectric Breakdown testing over a wide range of electric fields and test temperatures. The data generated indicates that the field and temperature acceleration factors are the same for all the areas tested indicating that the failure mechanism is the same even though the times to failure are different for all the area sizes. The paper will explain and model the area effect on TDDB lifetime and use the model to predict gate oxide reliability in the design cycle. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Analog Devices Inc, Limerick, Ireland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Prendergast, J (reprint author), Analog Devices Inc, Raheen Ind Estate, Limerick, Ireland. NR 8 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD JUN-AUG PY 1998 VL 38 IS 6-8 BP 1121 EP 1125 DI 10.1016/S0026-2714(98)00140-1 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 129FZ UT WOS:000076454300045 ER PT J AU Friday, D AF Friday, D TI Microwave technology directors and measurement requirements for the 21st century SO MICROWAVE JOURNAL LA English DT Editorial Material C1 Univ Colorado, NIST, Boulder, CO 80309 USA. RP Friday, D (reprint author), Univ Colorado, NIST, Boulder, CO 80309 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU HORIZON HOUSE PUBLICATIONS INC PI NORWOOD PA 685 CANTON ST, NORWOOD, MA 02062 USA SN 0192-6225 J9 MICROWAVE J JI Microw. J. PD JUN PY 1998 VL 41 IS 6 BP 110 EP + PG 3 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA ZT915 UT WOS:000074140800022 ER PT J AU Bluestein, HB MacGorman, DR AF Bluestein, HB MacGorman, DR TI Evolution of cloud-to-ground lightning characteristics and storm structure in the spearman, Texas, tornadic supercells of 31 May 1990 SO MONTHLY WEATHER REVIEW LA English DT Article ID THUNDERSTORMS; FLASHES AB On 31 May 1990, four tornadic supercell storms formed sequentially near the intersection of a dryline and an outflow boundary in the northern Texas panhandle. "Staccato" lightning flashes, which have been hypothesized to be positive ground flashes, were observed beneath the anvil of one storm during the most violent tornado that the storm produced. Evidence was found from a lightning mapping system that at least some of the staccato flashes were negative ground flashes. Although the four supercell storms on this day formed in approximately the same area, traveled over roughly the same region, and produced tornadoes and large hail, the relationship between the genesis and evolution of tornadoes and the polarity and flash rates of ground hashes varied widely, as in previous studies. The second of the supercell storms had low-precipitation supercell characteristics; the third and fourth did not. In previously studied storms, ground flash activity in low-precipitation supercell storms has always been dominated by positive ground flashes. However, all ground flashes detected in the second, low-precipitation storm were negative ground flashes. Positive ground flashes dominated ground flash activity in the third and fourth supercell storms for roughly their first hour, after which the dominant polarity switched to negative. In the third storm, the maximum positive ground flash rate before this polarity reversal was 1 min(-1) and the most intense tornado produced by the storm occurred before the maximum positive ground hash rate. In the fourth storm, positive ground flash rates increased to 7.4 min(-1) over a period of 30 min early in the storm, followed by a rapid decrease to 0 min(-1) over the next 10 min; the most intense tornado produced by the fourth storm occurred during the lull in ground flash rates following the large maximum. These observations are consistent with a previously reported tendency for a storm dominated by positive ground flashes to produce its most violent tornado after it attains its maximum positive ground flash rate, whenever the rate is in excess of 1.5 min(-1). C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. NOAA, Environm Res Lab, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Bluestein, HB (reprint author), Univ Oklahoma, Sch Meteorol, 100 E Boyd,Room 1310, Norman, OK 73019 USA. NR 27 TC 24 Z9 25 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1998 VL 126 IS 6 BP 1451 EP 1467 DI 10.1175/1520-0493(1998)126<1451:EOCTGL>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100UX UT WOS:000074834700005 ER PT J AU Mo, KC Higgins, RW AF Mo, KC Higgins, RW TI The Pacific-South American modes and tropical convection during the Southern Hemisphere winter SO MONTHLY WEATHER REVIEW LA English DT Article ID OUTGOING LONGWAVE RADIATION; NORTH PACIFIC; LIFE-CYCLES; CIRCULATION ANOMALIES; GEOPOTENTIAL HEIGHT; BLOCKING EPISODE; TELECONNECTIONS; OSCILLATIONS; DATASET; EDDIES AB Atmospheric circulation features and convection patterns associated with two leading low-frequency modes in the Southern Hemisphere (SH) are examined in multiyear global reanalyses produced by NCEP-NCAR and NASA-DAO. The two leading modes, referred to as the Pacific-South American (PSA) modes, are represented by the first two EOF patterns. The two patterns are in quadrature with each other and are dominated by wavenumber 3 in midlatitudes with large amplitudes in the Pacific-South American sector. In the Pacific, anomalies in the subtropics and in the midlatitudes are opposite in phase. Taken together, the two PSA modes represent the intraseasonal oscillation in the SH with periods of roughly 40 days. The evolution of the PSA modes shows a coherent eastward propagation. A composite analysis was conducted to study the evolution of tropical convection and the corresponding circulation changes associated with the PSA modes. Outgoing longwave radiation (OLR) anomaly composites during the mature phase of the PSA modes resemble the first two leading EOFs of OLR anomalies (OLRA) in the Tropics. Composites of OLRA show an east-west dipole structure roughly 5-10 days prior to the onset of persistent PSA events. The PSA 1 mode is associated with enhanced convection in the Pacific between 140 degrees E and 170 degrees W and suppressed convection over the Indian Ocean. The PSA 2 mode is linked to tropical heating anomalies in the central Pacific extending from 160 degrees E to 150 degrees W just south of the equator and suppressed convection in the western Pacific with a maximum at 20 degrees N. Contributions are from both interannual and intraseasonal bands. C1 NOAA, Natl Weather Serv, Climate Predict Ctr, NCEP, Washington, DC 20233 USA. RP Mo, KC (reprint author), NOAA, Natl Weather Serv, Climate Predict Ctr, NCEP, W-NP52,4700 Silver Hill Rd,Stop 9910, Washington, DC 20233 USA. NR 26 TC 188 Z9 193 U1 0 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1998 VL 126 IS 6 BP 1581 EP 1596 DI 10.1175/1520-0493(1998)126<1581:TPSAMA>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100UX UT WOS:000074834700010 ER PT J AU Vukicevic, T Bao, JW AF Vukicevic, T Bao, JW TI The effect of linearization errors on 4DVAR data assimilation SO MONTHLY WEATHER REVIEW LA English DT Article ID VARIATIONAL DATA ASSIMILATION; PARAMETERIZED DISCONTINUITIES; GENERALIZED ADJOINT; PHYSICAL PROCESSES; MODEL; EQUATION AB The authors show that the linear approximation errors-in the presence of a discontinuous convective parameterization operator are large for a small number of grid points where the noise produced by the convective parameterization is largest. These errors are much smaller for "smooth convective" points in the integration domain and for the nonconvective regions. Decreasing of the amplitude of initial perturbations does not reduce the errors in noisy points. This result indicates that the tangent linear model solution is erroneous in these points due to the linearization that does not include the linear variations of regime changes (i;e., due to use of standard method). The authors then show that the quality of local four-dimensional variational (4DVAR) data assimilation results is correlated with the linearization errors: Slower convergence is associated with large errors. Consequently, the 4DVAR assimilation results are different for different convective points in the integration domain. The negative effect of linearization errors is not, however, significant for the cases that are studied. Erroneous points slightly degrade 4DVAR results in the remaining points. This degradation is reflected in decreased monotonicity of the cost function gradient reduction with iterations. These results suggest that there is a probability for locally bad 4DVAR assimilation results when using standard adjoints of discontinuous parameterizations. In practice, when using for example observations, this is unlikely to cause errors that are larger than errors associated with other approximations and uncertainties in the data assimilation integrations such as the linear approximation errors and the uncertainties associated with the background and model errors statistics. This conclusion is similar to the conclusions of prior 4DVAR assimilation studies that use the standard adjoints but unlike in these studies the results in the current study show that 1) the linearization errors are nonnegligible for small-amplitude initial perturbations and 2) the assimilation results are locally and even globally affected by these errors. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Boulder, CO USA. RP Vukicevic, T (reprint author), Natl Ctr Atmospher Res, Pob 3000, Boulder, CO 80307 USA. RI Vukicevic, Tomislava/B-1386-2014 NR 24 TC 15 Z9 15 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1998 VL 126 IS 6 BP 1695 EP 1706 DI 10.1175/1520-0493(1998)126<1695:TEOLEO>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100UX UT WOS:000074834700016 ER PT J AU Hong, SY Juang, HMH AF Hong, SY Juang, HMH TI Orography blending in the lateral boundary of a regional model SO MONTHLY WEATHER REVIEW LA English DT Article AB A simple method to employ an orography blending technique near the lateral boundary of the regional model is proposed. The method blends the orography of the regional model on the lateral boundary with that of the global or coarser resolution regional model. This method is tested in the NCEP Regional Spectral Model. A long-range prediction experiment of one month's duration is conducted in the East Asian region. It is found that the proposed method provides regional model forecasts consistent with the global model forecasts without a discernible systematic bias. It is likely that modifying the regional model orography following the values of global model or analysis data is more efficient than elaborating the numerics of a lateral boundary scheme to eliminate systematic error. C1 EMC, NCEP, GSC, SAIC, Camp Springs, MD 20746 USA. RP Hong, SY (reprint author), EMC, NCEP, GSC, SAIC, Room 207,5200 Auth Rd, Camp Springs, MD 20746 USA. RI Hong, Song-You/I-3824-2012 NR 8 TC 23 Z9 23 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1998 VL 126 IS 6 BP 1714 EP 1718 DI 10.1175/1520-0493(1998)126<1714:OBITLB>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 100UX UT WOS:000074834700018 ER PT J AU Evans, CJ AF Evans, CJ TI Comment on the paper "Interferometric testing of optical surfaces: absolute measurements of flatness" SO OPTICAL ENGINEERING LA English DT Article C1 Natl Inst Stand & Technol, Div Precis Engn, Gaithersburg, MD 20899 USA. RP Evans, CJ (reprint author), Natl Inst Stand & Technol, Div Precis Engn, A-117 Metrol Bldg, Gaithersburg, MD 20899 USA. NR 10 TC 10 Z9 11 U1 0 U2 2 PU SPIE - INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING PI BELLINGHAM PA POB 10, BELLINGHAM, WA 98227-0010 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JUN PY 1998 VL 37 IS 6 BP 1880 EP 1882 DI 10.1117/1.601704 PG 3 WC Optics SC Optics GA ZT109 UT WOS:000074049300034 ER PT J AU Satija, SK Gallagher, PD Karim, A Fetters, LJ AF Satija, SK Gallagher, PD Karim, A Fetters, LJ TI Neutron reflectivity study of a chemically end-grafted polystyrene brush in a binary solvent mixture SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE neutron reflectivity; polystyrene; binary solvent mixture ID POLYMER BRUSH; PREFERENTIAL SOLVATION; DENSITY PROFILE; COLLAPSE; QUALITY AB We report neutron reflectivity measurements on a deuterated polystyrene brush chemically end-grafted onto a silicon surface and immersed in a mixture of cyclohexane and methanol. The solvents by themselves form a binary liquid mixture which phase separates upon lowering the temperature. Here the results for a solvent composition rich in methanol are reported. At high temperatures, the brush is collapsed as compared to its height measured in pure cyclohexane. However, upon lowering the temperature, the brush height increases substantially, indicating that excess cyclohexane is adsorbed within the brush as the solvent phase separation temperature is approached. By varying the deuterium content of the cyclohexane, we have determined that the solvent composition within the brush layer becomes nearly pure cyclohexane as the phase separation temperature is approached. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NIST, Div Polymer, Gaithersburg, MD 20899 USA. Exxon Corp Res Lab, Annandale, NJ USA. RP Satija, SK (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 14 TC 7 Z9 7 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 204 EP 207 DI 10.1016/S0921-4526(98)00232-4 PG 4 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900036 ER PT J AU Majkrzak, CF Berk, NF Dura, JA Satija, SK Karim, A Pedulla, J Deslattes, RD AF Majkrzak, CF Berk, NF Dura, JA Satija, SK Karim, A Pedulla, J Deslattes, RD TI Phase determination and inversion in specular neutron reflectometry SO PHYSICA B LA English DT Article; Proceedings Paper CT 5th International Conference on Surface X-Ray and Neutron Scattering (SXNS-5) CY JUL 13-17, 1997 CL ST CATHERINES COLL, OXFORD, ENGLAND HO ST CATHERINES COLL DE neutron reflectometry; phase angle; inversion ID REFLECTION AB We present results testing the experimental feasibility of recently discovered solutions of the dynamical phase problem for specular reflection. Using layers of Cu, Ni, and Mo as references, the real and imaginary parts of the complex reflection amplitude were measured from neutron reflectivities for an asymmetric composite film consisting of deuterated polystyrene and Si. The reflection amplitude was also measured from neutron reflectivity without references for a symmetric deuterated polystyrene film. These amplitudes were inverted using the Gel'fand-Levitan-Marchenko equation to produce scattering length density profiles for the films studied. The inverted profiles compared reasonably well to the expected potentials. We conclude that such methods are practical with current instrumentation. (C) 1998 Published by Elsevier Science B.V. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NIST, Div Polymer, Gaithersburg, MD 20899 USA. NIST, Div Phys, Gaithersburg, MD 20899 USA. RP Berk, NF (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Dura, Joseph/B-8452-2008 OI Dura, Joseph/0000-0001-6877-959X NR 14 TC 39 Z9 40 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN 1 PY 1998 VL 248 BP 338 EP 342 DI 10.1016/S0921-4526(98)00260-9 PG 5 WC Physics, Condensed Matter SC Physics GA ZZ546 UT WOS:000074740900059 ER PT J AU Itano, WM Bergquist, JC Bollinger, JJ Wineland, DJ Eichmann, U Raizen, MG AF Itano, WM Bergquist, JC Bollinger, JJ Wineland, DJ Eichmann, U Raizen, MG TI Complementarity and Young's interference fringes from two atoms SO PHYSICAL REVIEW A LA English DT Article ID RESONANCE FLUORESCENCE; QUANTUM JUMPS; 2 ATOMS; UNCERTAINTY AB The interference pattern of the resonance fluorescence from a J=1/2 to J=1/2 transition of two identical atoms confined in a three-dimensional harmonic potential is calculated. The thermal motion of the atoms is included. Agreement is obtained with experiments; [U. Eichmann et al., Phys. Rev. Lett. 70, 2359 (1993)]. Contrary to some theoretical predictions, but in agreement with the present calculations, a fringe visibility greater than 50% can be observed with polarization:selective detection. The dependence of the fringe visibility on polarization has a simple interpretation! based on whether pr: not it is possible in principle to determine which atom emitted the photon. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Max Born Inst Nonlinear Opt & Short Pulse Spect, D-12489 Berlin, Germany. Univ Texas, Dept Phys, Austin, TX 78712 USA. RP Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. NR 29 TC 52 Z9 52 U1 3 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4176 EP 4187 DI 10.1103/PhysRevA.57.4176 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600017 ER PT J AU Tiesinga, E Williams, CJ Julienne, PS AF Tiesinga, E Williams, CJ Julienne, PS TI Photoassociative spectroscopy of highly excited vibrational levels of alkali-metal dimers: Green-function approach for eigenvalue solvers SO PHYSICAL REVIEW A LA English DT Article ID DISCRETE VARIABLE REPRESENTATION; BOSE-EINSTEIN CONDENSATION; REACTIVE SCATTERING; HYPERFINE-STRUCTURE; ATOM COLLISIONS; BOUND-STATES; NA-2; LIFETIME; MOLECULE; VAPOR AB Understanding high-precision photoassociative spectroscopy of laser-cooled alkali-metal atoms involves modeling an extremely dense level structure of weakly bound molecules: in the region where coriolis and hyperfine interactions become comparable to electronic interactions. We describe an iterative eigenvalue solver suitable for resolving these bound states that is based on finding eigenvalues of the shifted inverse or Green-function operator. Nonlinear coordinate transformations applied to the nuclear motion are introduced to minimize the dimensionality of the discretized Hamiltonian. The formalism is applied to resolve the hyperfine structure of rovibrational levels of the Na(P-2) + Na(S-2) dimer. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Inst Def Anal, Alexandria, VA 22311 USA. RP Tiesinga, E (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RI Williams, Carl/B-5877-2009; Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 37 TC 48 Z9 48 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4257 EP 4267 DI 10.1103/PhysRevA.57.4257 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600028 ER PT J AU Wang, XT Wang, H Gould, PL Stwalley, WC Tiesinga, E Julienne, PS AF Wang, XT Wang, H Gould, PL Stwalley, WC Tiesinga, E Julienne, PS TI Observation of the pure long-range 1(u) state of an alkali-metal dimer by photoassociative spectroscopy SO PHYSICAL REVIEW A LA English DT Article ID COOLED ATOMS AB The pure long-range 1(u) state of an alkali-metal dimer is observed in K-39(2) using photoassociative spectroscopy of ultracold atoms. High-resolution spectra for vibrational levels upsilon=0-->7 are recorded by resonance-enhanced two-photon ionization. Strong rotation-hyperfine couplings are observed. Major molecular constants and a hyperfine structure analysis are presented. This 1, state is useful as an ungerade Franck-Condon "window" at large internuclear distance for studies of highly excited long-range interactions. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Univ Connecticut, Inst Mat Sci, Storrs, CT 06269 USA. Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. RP Wang, XT (reprint author), Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 16 TC 22 Z9 22 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4600 EP 4603 DI 10.1103/PhysRevA.57.4600 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600069 ER PT J AU Bridges, JM Wiese, WL AF Bridges, JM Wiese, WL TI Transition probabilities for the 3s S-3(0)-4p P-3 and 3s S-5(0)-4p P-5 multiplets in OI SO PHYSICAL REVIEW A LA English DT Article ID SPECTROSCOPIC COUPLING SCHEME; OSCILLATOR-STRENGTHS; NEUTRAL OXYGEN; TESTS AB We have measured the atomic transition probabilities of two weak El multiplets in neutral oxygen for which advanced atomic structure calculations have encountered problems due to severe cancellation of positive and negative parts of the transition integrand. Measurements were made in emission from a wall-stabilized are. Our results differ significantly from those of all recent calculations. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 16 TC 12 Z9 12 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1998 VL 57 IS 6 BP 4960 EP 4963 DI 10.1103/PhysRevA.57.4960 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZU090 UT WOS:000074160600108 ER PT J AU Habib, YM Lehner, CJ Oates, DE Vale, LR Ono, RH Dresselhaus, G Dresselhaus, MS AF Habib, YM Lehner, CJ Oates, DE Vale, LR Ono, RH Dresselhaus, G Dresselhaus, MS TI Measurements and modeling of the microwave impedance in high-T-c grain-boundary Josephson junctions: Fluxon generation and rf Josephson-vortex dynamics SO PHYSICAL REVIEW B LA English DT Article ID YBA2CU3O7-X THIN-FILMS; POLYCRYSTALLINE SUPERCONDUCTORS; SURFACE-RESISTANCE; PENETRATION AB Measurements and modeling of the microwave-frequency (rf) power dependence of the impedance in Y-Ba-Cu-O thin-film grain-boundary Josephson junctions (JJ's) are presented. Microwave impedance measurements were performed using a stripline resonator with an engineered grain-boundary JJ as a function of rf current (10(-4)-1 A) and temperature (5-70 K). To understand the observed power dependence, we have developed a long-junction model which allows for Josephson-vortex creation, annihilation, and motion. The impedance calculated using the long-junction model fits the measured data qualitatively. We show that Josephson vortices generated by the rf fields cause nonlinearities in the impedance, resulting in increases in both resistance and reactance with steps in the resistance due to flux quantization. These observations and analysis of Josephson-vortex effects at microwave frequencies have important implications for understanding rf power handling in high-T-c films. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Lincoln Lab, Lexington, MA 02173 USA. USAF, Rome Lab, Bedford, MA 01731 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. MIT, Francis Bitter Natl Magnet Lab, Cambridge, MA 02139 USA. MIT, Dept Elect Engn & Comp Sci, Cambridge, MA 02139 USA. RP Habib, YM (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. NR 26 TC 53 Z9 53 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1998 VL 57 IS 21 BP 13833 EP 13844 DI 10.1103/PhysRevB.57.13833 PG 12 WC Physics, Condensed Matter SC Physics GA ZT216 UT WOS:000074061700069 ER PT J AU Glotzer, SC Jan, N Lookman, T MacIsaac, AB Poole, PH AF Glotzer, SC Jan, N Lookman, T MacIsaac, AB Poole, PH TI Dynamical heterogeneity in the Ising spin glass SO PHYSICAL REVIEW E LA English DT Article ID MULTIDIMENSIONAL NMR; TRANSITION; RELAXATION; LIQUIDS; PHASE AB We investigate the relationship between bulk and local relaxation in the Ising spin glass (in two and three dimensions) for temperatures above but approaching the glass transition temperature, using Monte Carlo computer simulations. We find that the stretched exponential form of the bulk spin autocorrelation function results from a spatial average over a broad range of behavior, from strongly nonexponential to nearly exponential, for the local autocorrelation functions. The spatial correlation of single-site relaxation times obtained from these functions provides a length scale for dynamical heterogeneity that grows with decreasing temperature. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. St Francis Xavier Univ, Dept Phys, Antigonish, NS B2G 2W5, Canada. Univ Western Ontario, Dept Appl Math, London, ON N6A 5B7, Canada. RP Glotzer, SC (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RI Poole, Peter/C-7943-2009 OI Poole, Peter/0000-0001-5985-0585 NR 21 TC 29 Z9 29 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP 7350 EP 7353 DI 10.1103/PhysRevE.57.7350 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400149 ER PT J AU Karim, A Douglas, JF Lee, BP Glotzer, SC Rogers, JA Jackman, RJ Amis, EJ Whitesides, GM AF Karim, A Douglas, JF Lee, BP Glotzer, SC Rogers, JA Jackman, RJ Amis, EJ Whitesides, GM TI Phase separation of ultrathin polymer-blend films on patterned substrates SO PHYSICAL REVIEW E LA English DT Article AB The phase separation of ultrathin polymer-blend films of polystyrene and polybutadiene on microcontact printed alkanethiol patterns with hydrophobic and hydrophilic end groups (-CH3 and -COOH) is investigated by atomic force microscopy. Simulations suggest that the phase-separation morphology can be controlled through patterns that modulate the polymer-surface interaction, and this concept is verified experimentally, Length scale pattern control is found to be limited to a scale on the order of a few micrometers. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. Harvard Univ, Dept Biol Chem, Cambridge, MA 02138 USA. RP Karim, A (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 12 TC 86 Z9 87 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 1998 VL 57 IS 6 BP R6273 EP R6276 DI 10.1103/PhysRevE.57.R6273 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA ZU947 UT WOS:000074252400012 ER PT J AU Schmelling, D Poster, D Chaychian, M Neta, P McLaughlin, W Silverman, J Al-Sheikhly, M AF Schmelling, D Poster, D Chaychian, M Neta, P McLaughlin, W Silverman, J Al-Sheikhly, M TI Applications of ionizing radiation to the remediation of materials contaminated with heavy metals and polychlorinated biphenyls SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Meeting on Radiation Processing (IMRP-10) CY MAY 11-16, 1997 CL ANAHEIM, CALIFORNIA DE ionizing radiation; gamma radiation; electron beam; lead; mercury; cadmium; polychlorinated biphenyls; surfactants ID AQUEOUS-SOLUTION; REDUCTION AB We have investigated the removal from water of heavy metals and chelated heavy metal compounds using electron beam and gamma radiation. Parameter analyses include the effect of dissolved oxygen and the influence of adding various buffers and radical scavengers. Complete removal (>99%) of mercury, lead and cadmium ions, both free and chelated within EDTA, was achieved using radiation doses ranging from 3-100 kGy. We have also studied the radiation induced degradation of polychlorinated biphenyls (PCBs) in aqueous-organic and aqueous micellar systems. Rates and extent of dechlorination have been quantified in different solution matrices; reaction byproducts and intermediate species have been identified; and the influences of dissolved oxygen and pH have been evaluated. The presence of a carbonate buffer was observed to significantly enhance PCB dechlorination yields by reducing concentrations of H3O+. Ionizing radiation was effective in degrading PCBs in micellar solutions but scavenging of e(aq)(-) by the surfactant lowered reaction efficiencies. C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NIST, Gaithersburg, MD 20899 USA. RP Schmelling, D (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NR 16 TC 12 Z9 19 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 1998 VL 52 IS 1-6 BP 371 EP 377 DI 10.1016/S0969-806X(98)00036-X PG 7 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA ZX723 UT WOS:000074548000073 ER PT J AU Nablo, SV Wood, JC Desrosiers, MF Nagy, VY AF Nablo, SV Wood, JC Desrosiers, MF Nagy, VY TI A fluidized bed process for electron sterilization of powders SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Meeting on Radiation Processing (IMRP-10) CY MAY 11-16, 1997 CL ANAHEIM, CALIFORNIA AB A small capacity (100 g.s(-1)) pilot system is described for presentation of powders and fine aggregates at high velocity, to an electron beam. Electron beam dose rate is continuously monitored in real time, while the thickness of the fluidized bed used to pneumatically transport the product can be monitored and controlled using beta-gauge techniques. Using electron paramagnetic resonance (EPR) techniques, alanine power mixed with the product is used for precise determination of dose delivered to the powder stream. Thin film dosimeters transported in the bed are also used for dose determination. Results with a variety of products are presented using both dose rate and bed velocity as the independent variables. Lethality data for the bioburdens present in several powdered foodstuffs are discussed. C1 Elect Proc Syst Inc, N Billerica, MA 01862 USA. NIST, Gaithersburg, MD 20899 USA. RP Nablo, SV (reprint author), Elect Proc Syst Inc, N Billerica, MA 01862 USA. NR 15 TC 2 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 1998 VL 52 IS 1-6 BP 479 EP 485 DI 10.1016/S0969-806X(98)00179-0 PG 7 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA ZX723 UT WOS:000074548000094 ER PT J AU Kovacs, A Wojnarovits, L Kurucz, C Al-Sheikhly, M McLaughlin, WL AF Kovacs, A Wojnarovits, L Kurucz, C Al-Sheikhly, M McLaughlin, WL TI Large-scale dosimetry using dilute methylene blue dye in aqueous solution SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Meeting on Radiation Processing (IMRP-10) CY MAY 11-16, 1997 CL ANAHEIM, CALIFORNIA DE methylene blue dye; ionizing radiation; radiation dosimetry; gamma and electron irradiation AB The radiolytic bleaching of neat aerated methylene blue solutions is relatively stable, when irradiated to doses in the range of 50 to 500 Gy and measured at the main peak of absorption band of the dye (664 nn). The useful range can be extended up to about 5 kGy if the aqueous dye solution contains about 0.1 % ethanol by volume and to 10 kGy with 5 % ethanol. By increasing the concentration of the dye in the presence of 5 % ethanol doses up to about 30 kGy can be measured. The spectrophotometric readings have to be made during a period of post irradiation stability of 24 hours, after which there is about a 10 % increase in absorbance over the next three days due to regeneration of the dye by spontaneous oxidation. Since the industrial grade monovalent dye salt is very inexpensive and is relatively non-toxic, it may be used for dosimetry studies in quality control tests of electron beam processing of large volumes of waste water, when typical doses in the range of 5-30 kGy are required. The influences of dose, dose rate and solute concentration on the bleaching process have been investigated in terms of the decrease of the absorbance of the dye. C1 Hungarian Acad Sci, Inst Isotopes, H-1525 Budapest, Hungary. Univ Miami, Dept Ind Sci & Technol, Coral Gables, FL 33124 USA. Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Kovacs, A (reprint author), Hungarian Acad Sci, Inst Isotopes, POB 77, H-1525 Budapest, Hungary. NR 2 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 1998 VL 52 IS 1-6 BP 539 EP 542 DI 10.1016/S0969-806X(98)00091-7 PG 4 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA ZX723 UT WOS:000074548000106 ER PT J AU Sheridan, P McMahan, G Hammerstrom, K Pulich, W AF Sheridan, P McMahan, G Hammerstrom, K Pulich, W TI Factors affecting restoration of Halodule wrightii to Galveston bay, Texas SO RESTORATION ECOLOGY LA English DT Article ID EELGRASS ZOSTERA-MARINA; PLANTED SEAGRASS BEDS; MARITIMA L SL; SUBMERGED VEGETATION; SEASONAL GROWTH; TAMPA-BAY; DYNAMICS; COMPONENTS; SEDIMENTS; BIOMASS AB Experimental restoration of Halodule wrightii (shoalgrass) to its former range on Galveston Island, Texas, began in April 1994. We tested the effects of site, planting density, water depth, and fertilizer addition on survival and growth through June 1996. Temperature, salinity, light transmittance, turbidity, and sediment properties at two restoration sites, Redfish Cove and Snake Island Cove, were similar to those in naturally occurring grassbeds in nearby Christmas Bay. Halodule survival, coverage, and new shoot densities were affected by site (significantly higher at Redfish Cove than at Snake Island Cove, which eventually failed), by planting density (significantly higher when planted on 0.25-m or 0.5-m centers rather than on 1.0-m centers), and by water depth (significantly higher when planted in relatively shallow water). Propagation (spreading from transplant units) was significantly greater from 0.25-m or 0.5-m center plantings but was not consistently affected by site or water depth. Fertilizer enhanced propagation but not survival. After two years, Redfish Cove produced belowground biomass similar to that observed in Christmas Bay, but aboveground biomass remained significantly less. Snake Island Cove plant mortality in September 1995 may have been presaged by low root-rhizome carbohydrate levels observed in October 1994, but causes remain unknown. Further restoration of Halodule to Galveston Bay is possible at selected sites, but structural equivalency will take longer than two growing seasons to achieve. C1 Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Galveston, TX 77551 USA. Texas Pk & Wildlife Dept, Resource Protect Div, Austin, TX 78704 USA. RP Sheridan, P (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 4700 Ave U, Galveston, TX 77551 USA. NR 38 TC 36 Z9 39 U1 6 U2 16 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 1061-2971 J9 RESTOR ECOL JI Restor. Ecol. PD JUN PY 1998 VL 6 IS 2 BP 144 EP 158 DI 10.1046/j.1526-100X.1998.00625.x PG 15 WC Ecology SC Environmental Sciences & Ecology GA ZV113 UT WOS:000074270400004 ER PT J AU Richman, SJ Giaime, JA Newell, DB Stebbins, RT Bender, PL Faller, JE AF Richman, SJ Giaime, JA Newell, DB Stebbins, RT Bender, PL Faller, JE TI Multistage active vibration isolation system SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID FREQUENCY AB The major obstacle to the detection of low-frequency gravitational waves with an earth-based interferometer is seismic noise. The current design of the initial Laser Interferometer Gravitational-Wave Observatory (LIGO) receiver, now under construction, projects that ground noise will limit the operating band to frequencies above 40 Hz. In this article, we describe recent progress on the JILA active vibration isolation system. This device is being constructed to demonstrate the technology needed for useful reduction of low-frequency seismic noise in a gravitational wave interferometer. It consists of three spring-mounted stages, each of which provides both active and passive isolation. To date, all of the control loops on the first two of the three stages have been closed. Together they can reduce large vibrations by at least 70 dB in both vertical and horizontal directions at 1.5 Hz and above. (C) 1998 American Institute of Physics. [S0034-6748(98)04506-7] C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Richman, SJ (reprint author), Bur Int Poids & Mesures, Pavillon Breteuil, F-92312 Sevres, France. RI Stebbins, Robin/G-5009-2013 NR 12 TC 23 Z9 24 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2531 EP 2538 DI 10.1063/1.1148954 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100048 ER PT J AU Feldman, A Balzaretti, NM AF Feldman, A Balzaretti, NM TI A modification of Angstrom's method that employs photothermal radiometry to measure thermal diffusivity: Application to chemical vapor deposited diamond (vol 69, pg 237, 1998) SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Correction C1 Univ Fed Rio Grande Sul, Inst Fis, BR-91501970 Porto Alegre, RS, Brazil. RP Feldman, A (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Balzaretti, Naira/L-3417-2014 OI Balzaretti, Naira/0000-0003-2797-8618 NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 1998 VL 69 IS 6 BP 2576 EP 2576 DI 10.1063/1.1148977 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 108RK UT WOS:000075279100057 ER PT J AU Frey, HR AF Frey, HR TI National Oceanographic Data Center SO SEA TECHNOLOGY LA English DT Article C1 NOAA, Natl Environm Satellite Data & Informat Serv, Natl Oceanog Data Ctr, Washington, DC 20233 USA. RP Frey, HR (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Natl Oceanog Data Ctr, Washington, DC 20233 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD JUN PY 1998 VL 39 IS 6 BP 49 EP 54 PG 6 WC Engineering, Ocean SC Engineering GA ZW002 UT WOS:000074363700007 ER PT J AU Prahl, NA AF Prahl, NA TI Raster nautical charts: Staying the official course SO SEA TECHNOLOGY LA English DT Article C1 NOAA, Rockville, MD 20852 USA. RP Prahl, NA (reprint author), NOAA, Rockville, MD 20852 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD JUN PY 1998 VL 39 IS 6 BP 77 EP 79 PG 3 WC Engineering, Ocean SC Engineering GA ZW002 UT WOS:000074363700012 ER PT J AU Karmonik, C Udovic, TJ Paul, RL Rush, JJ Lind, K Hempelmann, R AF Karmonik, C Udovic, TJ Paul, RL Rush, JJ Lind, K Hempelmann, R TI Observation of dopant effects on hydrogen modes in SrCe0.95M0.05HxO3-delta by neutron vibrational spectroscopy SO SOLID STATE IONICS LA English DT Article DE defect interactions; electroceramics; neutron vibrational spectroscopy; proton conductors; strontium cerate ID INFRARED-ABSORPTION SPECTROSCOPY AB The influence of different dopants on the hydrogen dynamics in the high-temperature protonic conductor based on strontium cerate was investigated by means of neutron vibrational spectroscopy. The differences in the vibrational spectra up to an energy transfer of 130 meV are discussed. The results indicate the presence of a considerable amount of hydrogen associated with the dopant. The corresponding OH vibrational modes were found to depend strongly on the radius of the dopant cation. Moreover, a temperature study revealed a delocalization of the dopant-related hydrogen near 200 K and above. (C) 1998 Elsevier Science B.V. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Saarbrucken, Saarbrucken, Germany. RP Karmonik, C (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Karmonik, Christof/B-6150-2009 NR 11 TC 27 Z9 28 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD JUN PY 1998 VL 109 IS 3-4 BP 207 EP 211 DI 10.1016/S0167-2738(98)00088-5 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZT752 UT WOS:000074121600004 ER PT J AU Widmann, JF Aardahl, CL Davis, EJ AF Widmann, JF Aardahl, CL Davis, EJ TI Microparticle Raman spectroscopy SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article DE aerosol; electrodynamic levitation; microparticle; particle reaction; Raman spectroscopy ID INELASTIC LIGHT-SCATTERING; AEROSOLS; SPECTRA; RESONANCES; PARTICLES; SIZE AB The instrumentation and techniques used to explore the chemistry of microparticles (with dimensions of order 1 mu m and masses of order 1 pg) via Raman spectroscopy are surveyed, and recent applications are presented. The method features electrodynamic levitation of single microparticles and arrays of microparticles, so the most commonly used electrodynamic balances are described. Several examples of microparticle spectroscopy are given, including salt particle phase transition, chemical reaction between microparticles of Na2CO3 and (NH4)(2)SO4, the effects of morphology-dependent resonances on Raman spectra for organic droplets, and spectroscopic measurements during evaporation of a binary component microdroplet. (C) 1998 Elsevier Science B.V. C1 Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA. RP Davis, EJ (reprint author), NIST, Proc Measurement Div, Phys Bldg, Gaithersburg, MD 20899 USA. NR 25 TC 22 Z9 22 U1 4 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD JUN-JUL PY 1998 VL 17 IS 6 BP 339 EP 345 DI 10.1016/S0165-9936(98)00038-7 PG 7 WC Chemistry, Analytical SC Chemistry GA ZX453 UT WOS:000074517600015 ER PT J AU Reish, DJ Oshida, PS Mearns, AJ Ginn, TC Buchman, M AF Reish, DJ Oshida, PS Mearns, AJ Ginn, TC Buchman, M TI Effects of pollution on saltwater organisms SO WATER ENVIRONMENT RESEARCH LA English DT Review ID SULFIDE C1 Calif State Univ Long Beach, Dept Biol Sci, Long Beach, CA 90840 USA. US EPA, Washington, DC 20460 USA. NOAA, Seattle, WA USA. PTI Environm Serv, Bellevue, WA USA. RP Reish, DJ (reprint author), Calif State Univ Long Beach, Dept Biol Sci, Long Beach, CA 90840 USA. NR 203 TC 6 Z9 6 U1 0 U2 4 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 USA SN 1061-4303 EI 1554-7531 J9 WATER ENVIRON RES JI Water Environ. Res. PD JUN PY 1998 VL 70 IS 4 BP 931 EP 949 DI 10.2175/106143098X134550 PG 19 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA ZY282 UT WOS:000074604500042 ER PT J AU Whiton, RC Smith, PL Bigler, SG Wilk, KE Harbuck, AC AF Whiton, RC Smith, PL Bigler, SG Wilk, KE Harbuck, AC TI History of operational use of weather radar by US weather services. Part I: The pre-NEXRAD era SO WEATHER AND FORECASTING LA English DT Article AB The first part of a history of the use of storm surveillance radars by operational military and civil weather services in the United States is presented. The history of radar meteorological research is long and distinguished but already well described. Hence, this paper and its companion focus on the history of operational radar meteorology from its birth in World War II through the introduction of the first two operational Doppler weather radars. This part deals with the pre-Next-Generation Weather Radar era. An appendix to this part contains what is known by the authors about the principal technical characteristics of most of the radars discussed in both parts. C1 Air Weather Serv, Scott AFB, IL USA. NOAA, Natl Weather Serv, Washington, DC 20233 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Whiton, RC (reprint author), SAIC, 619 W Hwy 50, Ofallon, IL 62269 USA. NR 84 TC 7 Z9 9 U1 2 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 219 EP 243 DI 10.1175/1520-0434(1998)013<0219:HOOUOW>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600002 ER PT J AU Whiton, RC Smith, PL Bigler, SG Wilk, KE Harbuck, AC AF Whiton, RC Smith, PL Bigler, SG Wilk, KE Harbuck, AC TI History of operational use of weather radar by US weather services. Part II: Development of operational Doppler weather radars SO WEATHER AND FORECASTING LA English DT Article ID WSR-88D AB The second part of a history of the use of storm surveillance radars by operational military and civil weather services in the United States is presented. This part describes the genesis and evolution df two operational Doppler weather radars, the Next-Generation Weather Radar and Terminal Doppler Weather Radar. C1 Air Weather Serv, Scott AFB, IL USA. NOAA, Natl Weather Serv, Washington, DC 20233 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Whiton, RC (reprint author), SAIC, 619 W Hwy 50, Ofallon, IL 62269 USA. NR 52 TC 15 Z9 15 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 244 EP 252 DI 10.1175/1520-0434(1998)013<0244:HOOUOW>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600003 ER PT J AU Crum, TD Saffle, RE Wilson, JW AF Crum, TD Saffle, RE Wilson, JW TI An update on the NEXRAD program and future WSR-88D support to operations SO WEATHER AND FORECASTING LA English DT Article ID DOPPLER RADAR; WEATHER AB The operational network of WSR-88D systems is in place. These radars provide a large increase in performance and coverage over the radars they replaced-and in some locations are the first operational weather radars. The early years of experience using these radars have shown that they have contributed to increased weather warning and forecast performance. These systems must be regularly upgraded, however, to maintain a viable network, meet new requirements, and take advantage of new science and technology. In addition to the NEXRAD program's standard modification and retrofit process, the NEXRAD agencies (Department of Commerce/National Weather Service, Department of Defense, and Department of Transportalion/Federal Aviation Administration) have established a NEXRAD product improvement program to initiate major hardware upgrades to the WSR-88D. This paper describes the status of the NEXRAD program, improvements to the WSR-88D that have taken place, improvements that are planned, and a discussion of possible future changes to the WSR-88D and application of radar data. C1 NOAA, NWS, Norman, OK 73069 USA. NOAA, Natl Weather Serv, Off Syst Dev, Silver Spring, MD 20910 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Crum, TD (reprint author), NOAA, NWS, WSR-88D Operat Support Facil,1200 Westheimer Dr, Norman, OK 73069 USA. NR 35 TC 57 Z9 60 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 253 EP 262 DI 10.1175/1520-0434(1998)013<0253:AUOTNP>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600004 ER PT J AU Johnson, JT MacKeen, PL Witt, A Mitchell, ED Stumpf, GJ Eilts, MD Thomas, KW AF Johnson, JT MacKeen, PL Witt, A Mitchell, ED Stumpf, GJ Eilts, MD Thomas, KW TI The storm cell identification and tracking algorithm: An enhanced WSR-88D algorithm SO WEATHER AND FORECASTING LA English DT Article AB Accurate storm identification and tracking are basic and essential parts of radar and severe weather warning operations in today's operational meteorological community. Improvements over the original WSR-88D storm series algorithm have been made with the Storm Cell Identification and Tracking algorithm (SCIT). This paper discusses the SCIT algorithm, a centroid tracking algorithm with improved methods of identifying storms (both isolated and clustered or line storms). In an analysis of 6561 storm cells, the SCIT algorithm correctly identified 68% of all cells with maximum reflectivities over 40 dBZ and 96% of all cells with maximum reflectivities of 50 dBZ or greater. The WSR-88D storm series algorithm performed at 24% and 41%, respectively, for the same dataset. With better identification performance, the potential exists for better and more accurate tracking information. The SCIT algorithm tracked greater than 90% of all storm cells correctly. The algorithm techniques and results of a detailed performance evaluation are presented. This algorithm was included in the WSR-88D Build 9.0 of the Radar Products Generator software during late 1996 and early 1997. It is hoped that this paper will give new users of the algorithm sufficient background information to use the algorithm with confidence. C1 NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Johnson, JT (reprint author), NOAA, Environm Res Labs, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 21 TC 226 Z9 269 U1 1 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 263 EP 276 DI 10.1175/1520-0434(1998)013<0263:TSCIAT>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600005 ER PT J AU Edwards, R Thompson, RL AF Edwards, R Thompson, RL TI Nationwide comparisons of hail size with WSR-88D vertically integrated liquid water and derived thermodynamic sounding data SO WEATHER AND FORECASTING LA English DT Article AB This study tests hypothetical correspondences between size of severe hail, WSR-88D derived vertically integrated liquid water (VIL), and an array of thermodynamic variables derived from computationally modified sounding analyses. In addition, these associations are documented for normalized VIL using various sounding parameters, and statistical predictive value is assigned to the various VIL-based and sounding variables. The database was gathered from Weather Service Radar-1988 Doppler (WSR-88D) units nationwide from cases identified during real-lime operations and consists of over 400 hail events, each associated with a radar-observed VIL value and a modified observational sounding. Some parameters are found to increase in the mean with larger hail-size categories. Specific hail size, however, varies widely across the spectra of VIL, thermodynamic sounding variables, and combinations thereof, with only a few exceptions. No operationally useful parameters of value in hail-size prediction were discovered in the database of VIL and thermodynamic sounding data. These largely antihypothetical findings are compared with hail forecasting and warning techniques developed in the WSR-88D era-few in number and mostly regionalized and informal in nature-and with more widespread and empirical forecasting assumptions involving many of the same variables. C1 Storm Predict Ctr, Norman, OK 73069 USA. RP Edwards, R (reprint author), Storm Predict Ctr, 1313 Halley Cir, Norman, OK 73069 USA. NR 20 TC 34 Z9 37 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 277 EP 285 DI 10.1175/1520-0434(1998)013<0277:NCOHSW>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600006 ER PT J AU Witt, A Eilts, MD Stumpf, GJ Johnson, JT Mitchell, ED Thomas, KW AF Witt, A Eilts, MD Stumpf, GJ Johnson, JT Mitchell, ED Thomas, KW TI An enhanced hail detection algorithm for the WSR-88D SO WEATHER AND FORECASTING LA English DT Article ID GROWTH; FLOW AB An enhanced hail detection algorithm (HDA) has been developed for the WSR-88D to replace the original hail algorithm. While the original hail algorithm simply indicated whether or not a detected storm cell was producing hail, the new KDA estimates the probability of hail (any size), probability of severe-size hail (diameter greater than or equal to 19 mm), and maximum expected hail size for each detected storm cell. A new parameter, called the severe hail index (SHI), was developed as the primary predictor variable for severe-size hail. The SHI is a thermally weighted vertical integration of a storm cell's reflectivity profile. Initial testing on 10 storm days showed that the new HDA performed considerably better at predicting severe hail than the original hail algorithm. Additional testing of the new HDA on 31 storm days showed substantial regional variations in performance, with best results across the southern plains and weaker performance for regions farther east. C1 NOAA, ERL, Natl Severe Storms Lab, Norman, OK 73069 USA. Cooperat Inst Mesoscale Meteorol Studies, Norman, OK USA. RP Witt, A (reprint author), NOAA, ERL, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 38 TC 104 Z9 129 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 286 EP 303 DI 10.1175/1520-0434(1998)013<0286:AEHDAF>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600007 ER PT J AU Stumpf, GJ Witt, A Mitchell, ED Spencer, PL Johnson, JT Eilts, MD Thomas, KW Burgess, DW AF Stumpf, GJ Witt, A Mitchell, ED Spencer, PL Johnson, JT Eilts, MD Thomas, KW Burgess, DW TI The national severe storms laboratory mesocyclone detection algorithm for the WSR-88D SO WEATHER AND FORECASTING LA English DT Article ID TORNADO PREDICTION; DOPPLER RADAR AB The National Severe Storms Laboratory (NSSL) has developed a mesocyclone detection algorithm (NSSL MDA) for the Weather Surveillance Radar-1988 Doppler (WSR-88D) system designed to automatically detect and diagnose the Doppler radar radial velocity patterns associated with storm-scale (1-10-km diameter) vortices in thunderstorms. The NSSL MDA is an enhancement to the current WSR-88D Build 9.0 Mesocyclone Algorithm (88D B9MA). The recent abundance of WSR-88D observations indicates that a variety of storm-scale vortices are associated with severe weather and tornadoes, and not just those vortices meeting previously established criteria for mesocyclones observed during early Doppler radar studies in the 1970s and 1980s in the Great Plains region of the United States. The NSSL MDA's automated vortex detection techniques differ from the 88D B9MA, such that instead of immediately thresholding one-dimensional shear segments for strengths comparable to predefined mesocyclone parameters, the initial strength thresholds are set much lower, and classification and diagnosis are performed on the properties of the four-dimensional detections. The NSSL MDA also includes multiple range dependent strength thresholds, a more robust two-dimensional feature identifier, an improved three-dimensional vertical association technique, and the addition of time association and trends of vortex attributes. The goal is to detect a much broader spectrum of storm-scale vortices (so that few vortices are missed), and then diagnose them to determine their significance. The NSSL MDA is shown to perform better than the 88D B9MA at detecting storm-scale vortices and diagnosing significant vortices. Operational implications of the NSSL MDA are also presented. In light of the new WSR-88D observations of storm-scale vortices and their association with severe weather and tornadoes, it is clear that the operational paradigms of automated vortex detection require changes. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. Natl Weather Serv, Operat Support Facil, Norman, OK USA. RP Stumpf, GJ (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. EM stumpf@nsslsun.nssl.noaa.gov NR 43 TC 116 Z9 125 U1 2 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 304 EP 326 DI 10.1175/1520-0434(1998)013<0304:TNSSLM>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600008 ER PT J AU Lee, RR White, A AF Lee, RR White, A TI Improvement of the WSR-88D mesocyclone algorithm SO WEATHER AND FORECASTING LA English DT Article ID DOPPLER RADAR AB The build 9 Weather Surveillance Radar-1988/Doppler mesocyclone algorithm (B9MA) is designed to locate mesocyclones [rotating thunderstorm updrafts with diameters between 1.8 and 9.2 km (1-5 n mi)]. Because there is less than a one to one correspondence between tornadoes and mesocyclones, the B9MA alerts forecasters when it detects circulations that meet its criteria but tornadoes may not be observed. On the other hand, some tornadoes are not accompanied by large-scale mesocyclonic circulations. Weather radars cannot resolve small-scale tornadic circulations, and the B9MA may fail to alert forecasters that a tornado is present. The B9MA is only one of many tools that forecasters should use to predict tornado formation. This paper describes limitations of the B9MA and how to improve its performance. The correlation between algorithmic detections and severe weather occurrence may be optimized under the premise that storms with strong, deep rotations are more likely to be associated with severe weather. Some tornadic circulations missed by the B9MA can be detected when the value of threshold pattern vector, a B9MA adaptable parameter, is lowered. When a rotational strength filter is added to the program logic, some algorithm detections of nontornadic mesocyclones can be eliminated. C1 WSR88D Operat Support Facil, Norman, OK USA. RP Lee, RR (reprint author), NEXRAD Operat Support Facil, 1200 Westheimer Dr, Norman, OK 73069 USA. EM rlee@osf.noaa.gov NR 28 TC 9 Z9 10 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 341 EP 351 DI 10.1175/1520-0434(1998)013<0341:IOTWMA>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600010 ER PT J AU Mitchell, ED Vasiloff, SV Stumpf, GJ Witt, A Eilts, MD Johnson, JT Thomas, KW AF Mitchell, ED Vasiloff, SV Stumpf, GJ Witt, A Eilts, MD Johnson, JT Thomas, KW TI The National Severe Storms Laboratory tornado detection algorithm SO WEATHER AND FORECASTING LA English DT Article ID DOPPLER RADAR; WSR-88D; THUNDERSTORM; ENVIRONMENTS; WATERSPOUT; COLORADO AB The National Severe Storms Laboratory (NSSL) has developed and tested a tornado detection algorithm (NSSL TDA) that has been designed to identify the locally intense vortices associated with tornadoes using the WSR-88D base velocity data. The NSSL TDA is an improvement over the current Weather Surveillance Radar-1988 Doppler (WSR-88D) Tornadic Vortex Signature Algorithm (88D TVS). The NSSL TDA has been designed to address the relatively low probability of detection (POD) of the 88D TVS algorithm without a high false alarm rate (FAR). Using an independent dataset consisting of 31 tornadoes, the NSSL TDA has a POD of 43%, FAR of 48%, critical success index (CSI) = 31%, and a Heidke skill score (HSS) of 46% compared to the 88D TVS, which has a POD of 3%, FAR of 0%, CSI of 3%, and HSS of 0%. In contrast to the 88D TVS, the NSSL TDA identifies tornadic vortices by 1) searching for strong shear between velocity gates that are azimuthally adjacent and constant in range, and 2) not requiring the presence of an algorithm-identified mesocyclone. This manuscript discusses the differences between the NSSL TDA and the 88D TVS and presents a performance comparison between the two algorithms. Strengths and weaknesses of the NSSL TDA and NSSL's future work related to tornado identification using Doppler radar are also discussed. C1 NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Mitchell, ED (reprint author), NOAA, Environm Res Labs, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 54 TC 67 Z9 72 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 352 EP 366 DI 10.1175/1520-0434(1998)013<0352:TNSSLT>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600011 ER PT J AU Tipton, GA Howieson, ED Margraf, JA Keem, RR AF Tipton, GA Howieson, ED Margraf, JA Keem, RR TI Optimizing the WSR-88D mesocyclone tornadic vortex signature algorithm using WATADS - A case study SO WEATHER AND FORECASTING LA English DT Article AB A tornado outbreak occurred in east-central Minnesota around 0000 UTC 22 July 1995, within 80 km of the KMPX WSR-88D, at the Minneapolis-Chanhassen Weather Service Forecast Office (WSFO). The WSR-88D Mesocyclone/Tornadic Vortex Signature algorithm (MTA) identified only two Tornadic Vortex Signatures (TVSs) out of 14 confirmed tornadoes. A detailed examination of Doppler velocity products revealed operator-defined TVSs, intense gate-to-gate azimuthal shear, in 10 of the 14 storms. This outbreak presented an opportunity to optimize MTA performance because the algorithm performed poorly and the KMPX radar sampled many weak tornadoes at close range. Numerous combinations of two adaptable parameters, threshold pattern vector (TPV) and threshold TVS shear (TTS), were systematically tested using the WSR-88D Algorithm Testing and Display System (WATADS) and archive level II data. MTA's performance improved significantly when default values were optimized. The number of tornadoes detected increased from two to seven and average TVS alert lead rime, within 60 km of the radar, increased from 10 to 15 min, but the number of TVSs falsely identified increased from zero to two. In 1995 and 1996, the NEXRAD Operational Support Facility (OSF) authorized radar offices to lower TPV and TTS from their default values under the Unit Radar Committee level of change authority. Recommended values for TPV and TTS, based on research from data collected from many different sites across the United States, were provided for field office use. The values of TPV and TTS used to optimize MTA performance during the Minnesota tornado outbreak described in this paper independently agreed with OSF recommended values of TPV and TTS. C1 Natl Weather Serv, Chanhassen, MN 55317 USA. Natl Weather Serv, N Webster, IN USA. NEXRAD Operat Support Facil, Norman, OK USA. RP Tipton, GA (reprint author), Natl Weather Serv, 1733 Lake Dr W, Chanhassen, MN 55317 USA. NR 26 TC 2 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 367 EP 376 DI 10.1175/1520-0434(1998)013<0367:OTWMTV>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600012 ER PT J AU Fulton, RA Breidenbach, JP Seo, DJ Miller, DA O'Bannon, T AF Fulton, RA Breidenbach, JP Seo, DJ Miller, DA O'Bannon, T TI The WSR-88D rainfall algorithm SO WEATHER AND FORECASTING LA English DT Article ID NATIONAL-WEATHER-SERVICE; FLOOD PROGRAM; RADAR REFLECTIVITY; PRECIPITATION; NEXRAD; RIVER AB A derailed description of the operational WSR-88D rainfall estimation algorithm is presented. This algorithm, called the Precipitation Processing System, produces radar-derived rainfall products in real time for forecasters in support of the National Weather Service's warning and forecast missions. It transforms reflectivity factor measurements into rainfall accumulations and incorporates rain gauge data to improve the radar estimates. The products are used as guidance to issue hood watches and warnings to the public and as input into numerical hydrologic and atmospheric models. The processing steps to quality control and compute the rainfall estimates are described, and the current deficiencies and future plans for improvement are discussed. C1 Natl Weather Serv, Hydrol Res Lab, Off Hydrol, NOAA, Silver Spring, MD 20910 USA. WSR88D Operat Support Facil, Applicat Branch, Norman, OK USA. RP Fulton, RA (reprint author), Natl Weather Serv, Hydrol Res Lab, Off Hydrol, NOAA, W-OH1,1325 East West Highway, Silver Spring, MD 20910 USA. NR 54 TC 528 Z9 554 U1 7 U2 33 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 377 EP 395 DI 10.1175/1520-0434(1998)013<0377:TWRA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600013 ER PT J AU Andretta, TA Hazen, DS AF Andretta, TA Hazen, DS TI Doppler radar analysis of a Snake River plain convergence event SO WEATHER AND FORECASTING LA English DT Article ID CYCLONE; ZONE AB A convergence zone periodically forms in the Snake River plain (SRP) of eastern Idaho as a result of terrain-induced boundary layer flow under synoptic northwesterly flow at low and midlevels,Complex terrain in central and eastern Idaho is critical to the formation of this mesoscale feature, which is characterized by wind shift lines accompanied by cumulus or stratocumulus bands. These cloud bands routinely produce virga or light rain or light snow and, occasionally, result in moderate to heavy precipitation. Doppler weather radar analysis of a convergence event that produced heavy postfrontal snowfall in the lower SRP on 26 November 1995 is presented. This event was selected for study because significant snowfall resulted from a persistent and well-defined boundary layer convergence zone. The high-resolution (40 km) Eta Model data available from the National Centers for Environmental Prediction did not sufficiently resolve the mesoscale processes that initiated this event. The Era Model indicated postfrontal clearing in the SRP, generally northwest winds, and light precipitation amounts limited to higher terrain east of the SRP. The Springfield, Idaho, WSR-88D provided crucial real-time data to the forecaster who identified the convergence zone and issued short-term forecasts and a snow advisory for the affected area during this event. WSR-88D radial velocity and local mesonet data defined the region of convergence, and composite reflectivity data showed the development, persistence, and dissipation of snow within the convergence region. C1 Natl Weather Serv, Pocatello, ID 83204 USA. RP Hazen, DS (reprint author), Natl Weather Serv, 1320 Beechcraft Ave, Pocatello, ID 83204 USA. NR 11 TC 5 Z9 5 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 482 EP 491 DI 10.1175/1520-0434(1998)013<0482:DRAOAS>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600020 ER PT J AU Wolf, PL AF Wolf, PL TI WSR-88D radar depiction of supercell bow echo interaction: Unexpected evolution of a large, tornadic, "comma-shaped" supercell over eastern Oklahoma SO WEATHER AND FORECASTING LA English DT Article AB During a severe thunderstorm outbreak on 17 April 1995, a bowing line segment of severe thunderstorms intercepted an isolated supercell over eastern Oklahoma. The result of the supercell-bow echo interaction was unexpected. Instead of showing a weakening supercell, with diminished severe weather potential, as the bow echo's cold pool undercut, and spread in advance of, the supercell's updraft, WSR-88D imagery showed a different outcome. The bow echo rapidly weakened, while the supercell maintained its identity and severity for over an hour after the interaction rook place. WSR-88D imagery showed the evolution of a large high-precipitation supercell with a "comma-shaped" echo appearance. The archive II dataset from the WSR-88D radar at Inola, Oklahoma, was retrieved, and the reflectivity and velocity images for this event were reproduced and examined. The images showed the supercell-bow echo interaction and the changes to supercell structure and resultant weather that appeared to result from this interaction. This paper documents the remarkable evolution of a large, comma-shaped supercell, as shown by WSR-88D imagery, and illustrates an important scenario that can result from the interaction between a Supercell and a bow echo. C1 Natl Weather Serv, Jackson, MS USA. RP Wolf, PL (reprint author), Natl Weather Serv, 2142 S Tyler Rd, Wichita, KS 67209 USA. NR 14 TC 9 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 492 EP 504 DI 10.1175/1520-0434(1998)013<0492:WRDOSB>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600021 ER PT J AU Brown, RA AF Brown, RA TI Nomogram for aiding the interpretation of tornadic vortex signatures measured by Doppler radar SO WEATHER AND FORECASTING LA English DT Article AB A technique is described whereby an investigator can obtain a more representative peak velocity for a tornadic vortex signature (TVS) than can be obtained by using the extreme measured Doppler velocities associated with the signature. This technique, which is based on theoretical curves derived by scanning a simulated radar through Rankine combined vortices, is applied to WSR-88D Doppler velocity data collected in the Garden City, Kansas, tornado of 16 May 1995. The technique produces peak TVS velocities that are more consistent in time and height than those computed directly from the extreme measured values. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Brown, RA (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 12 TC 8 Z9 8 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 505 EP 512 DI 10.1175/1520-0434(1998)013<0505:NFATIO>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600022 ER PT J AU Witt, A Eilts, MD Stumpf, GJ Mitchell, ED Johnson, JT Thomas, KW AF Witt, A Eilts, MD Stumpf, GJ Mitchell, ED Johnson, JT Thomas, KW TI Evaluating the performance of WSR-88D severe storm detection algorithms SO WEATHER AND FORECASTING LA English DT Article ID UNITED-STATES; CLIMATOLOGY AB This paper discusses some important issues and problems associated with evaluating the performance of radar-based severe storm detection algorithms. The deficiencies of using Storm Data as a source of verification are examined. Options for equalizing the time- and space scales of the algorithm predictions and the corresponding verification data are presented. Finally, recommendations are given concerning the different evaluation procedures that are available. C1 NOAA, ERL, Natl Severe Storms Lab, Norman, OK 73069 USA. Cooperat Inst Mesoscale Meteorol Studies, Norman, OK USA. RP Witt, A (reprint author), NOAA, ERL, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 28 TC 51 Z9 52 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1998 VL 13 IS 2 BP 513 EP 518 DI 10.1175/1520-0434(1998)013<0513:ETPOWS>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 110VV UT WOS:000075402600023 ER PT J AU Pitman, RL Jehl, JR AF Pitman, RL Jehl, JR TI Geographic variation and reassessment of species limits in the "Masked" Boobies of the eastern Pacific Ocean SO WILSON BULLETIN LA English DT Article ID GALAPAGOS; SEABIRDS; MEXICO; EVENT; BIRDS AB Two distinct forms of Masked Booby (Sula dactylatra) occur in the eastern Pacific: (1) a yellow-billed form that includes a population on Clipperton Island and islands off western Mexico (S. d. "californica"), and another, unnamed, population on Las Islas Desventuradas, Chile, and (2) an orange-billed form [S. (d.) granti] that nests almost exclusively on the islands of the Galapagos and on Malpelo Island, Colombia. Quantitative comparisons, including discriminant function analysis (DFA) of standard morphological characters indicated that yellow-billed populations are only marginally different from one another, and neither is consistently separable from S. d. personata, a yellow-billed form that ranges over most of the tropical Pacific. Further, we found no consistent differences in bare-part coloration or plumage among yellow-billed populations. In contrast, DFA indicated morphological differences between orange- and yellow-billed populations. The orange-billed bird is smaller with a significantly shorter, shallower bill, shorter tarsus, and longer wings and tail. It is also more sexually dimorphic and has distinct plumage characters. Biological observations also support the distinctness of orange-billed birds. They typically nest on cliffs and steep slopes, whereas yellow-billed forms nest mainly on low, flat areas. A difference in habitat preference at sea resulted in a parapatric distribution: orange-billed birds away from colonies concentrated in nearshore waters off the coast of the Americas, whereas the yellow-billed forms foraged much farther offshore. Most importantly, orange- and yellow-billed birds paired assortatively where they nested sympatrically. Thus, based on morphological and biological differences, including positive assortative mating, we recommend that Sula granti be recognized as a separate species, the Nazca Booby. C1 Hubbs Sea World Res Inst, San Diego, CA 92019 USA. SW Fisheries Sci Ctr, La Jolla, CA 92037 USA. RP Jehl, JR (reprint author), Hubbs Sea World Res Inst, 2595 Ingraham St, San Diego, CA 92019 USA. EM jjehl@hubbs.sdsu.edu NR 44 TC 34 Z9 46 U1 0 U2 8 PU WILSON ORNITHOLOGICAL SOC PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710 USA SN 0043-5643 J9 WILSON BULL JI Wilson Bull. PD JUN PY 1998 VL 110 IS 2 BP 155 EP 170 PG 16 WC Ornithology SC Zoology GA ZY281 UT WOS:000074604400001 ER PT J AU Druzhko, AB Robertson, B Alvarez, R de Lera, AR Weetall, HH AF Druzhko, AB Robertson, B Alvarez, R de Lera, AR Weetall, HH TI Phototransformation and proton pumping activity of the 14-fluoro bacteriorhodopsin derivatives SO BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES LA English DT Article DE bacteriorhodopsin; retinal analog; mutant; photocycle; red-shifted species ID POINT-CHARGE MODEL; BIOLOGICAL-MATERIAL; PIGMENTS; ANALOGS; DECAY AB The photoinduced behavior and proton pumping characteristics of some bacteriorhodopsin (BR) analogs with fluorinated chromophores (all-trans 14-fluorinated [14-F] retinal and 13-cis 14-F retinal) derived from wild type (WT) and D96N mutant BR were investigated. These analogs were characterized using spectrophotometry and a highly sensitive electrochemical technique. Similar to the white membrane JW2N, the apomembranes WT ET 1000 and D96N form photoactive pigments with the 14-F chromophores. The resulting analogs have a major absorption band at 588 nm, Red-shifted pigment (lambda(max) less than or equal to 680 nm) has been previously observed as a minor component of the major 587-nm pigment in 14-F BR made with white membrane JW2N. A similar red-shifted pigment is formed under yellow light (lambda > 500 nm) only in the 14-F analogs derived from WT ET 1000, The measurements of the photoinduced transformation in 14-F WT analogs show that the photocycle of the major pigment occurs simultaneously with the process in the red region and is partially masked by the formation of the red-shifted species. The 14-F D96N samples have a significantly slower and more complicated photoinduced behavior. Electrochemical measurements show that the photoinduced transformation of the red species is not accompanied by proton transport. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Santiago de Compostela, Dept Organ Chem, Santiago De Compostela, Spain. RP Druzhko, AB (reprint author), Russian Acad Sci, Inst Theoret & Expt Biophys, Pushchino 142292, Moscow Reg, Russia. OI Rodriguez de Lera, Angel/0000-0001-6896-9078 NR 24 TC 16 Z9 16 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0005-2736 J9 BBA-BIOMEMBRANES JI Biochim. Biophys. Acta-Biomembr. PD MAY 28 PY 1998 VL 1371 IS 2 BP 371 EP 381 DI 10.1016/S0005-2736(98)00038-8 PG 11 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ZX804 UT WOS:000074557100020 PM 9630725 ER PT J AU Dyer, SD Rochford, KB AF Dyer, SD Rochford, KB TI Spectral tailoring of erbium superfluorescent fibre source SO ELECTRONICS LETTERS LA English DT Article AB The output spectrum of an erbium superfluorescent fibre source (SFS) is tailored by replacing the broadband mirror in the conventional double-pass design with a combination of reflective Bragg gratings. Increased bandwidth and a factor of two reduction in coherence length are demonstrated compared to a conventional SFS. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Dyer, SD (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 4 TC 14 Z9 14 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAY 28 PY 1998 VL 34 IS 11 BP 1137 EP 1139 DI 10.1049/el:19980748 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA ZW070 UT WOS:000074370900071 ER PT J AU Conkright, M AF Conkright, M TI ... and database flagged SO NATURE LA English DT Letter C1 Natl Oceanog Data Ctr, Ocean Climate Lab, Silver Spring, MD 20910 USA. RP Conkright, M (reprint author), Natl Oceanog Data Ctr, Ocean Climate Lab, OC5,1315 E West Highway, Silver Spring, MD 20910 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 28 PY 1998 VL 393 IS 6683 BP 318 EP 318 DI 10.1038/30634 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZQ593 UT WOS:000073883600034 ER PT J AU Li, QH Ferraro, R Grody, N AF Li, QH Ferraro, R Grody, N TI Detailed analysis of the error associated with the rainfall retrieved by the NOAA/NESDIS SSM/I algorithm - 1. Tropical oceanic rainfall SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SENSOR MICROWAVE IMAGER; SAMPLING ERRORS; STOCHASTIC-MODEL; SNOW COVER AB A general formulation has been established for the total error associated with passive microwave retrieval of space-time rainfall. The total error consists of two independent components: the sampling error and the algorithm error. The former arises from the discrete sampling scheme of a polar-orbiting satellite, and the later is the result of the imperfect algorithm used to convert the measured radiation to instantaneous rain rate. Rainfall data over the Tropical Ocean and Global Atmosphere/Coupled Ocean and Atmosphere Response Experiment (TOGA/COARE) region has been used to represent oceanic rainfall conditions to evaluate the error of the National Oceanic and Atmospheric Administration/National Environmental Satellite, Data, and Information Service (NOAA/NESDIS) Special Sensor Microwave/Imager (SSM/I) rainfall algorithm. Rainfall statistics that affect the sampling error have been obtained from radar data, which include mean, variance, and autocorrelation of areal rain. The magnitude of the variance and the strength of the autocorrelation are quantitatively related to the size of the averaging area. Instantaneous measurement errors on the FOV scale and the large scale (2.5 degrees box) are obtained by analyzing simultaneous observations of SSM/I and radar. Ba!;ed on these parameter values, the sampling error, the algorithm error, and the total error are computed as a function of sampling frequency, size of averaging area, and other factors. This study has demonstrated the feasibility of a procedure to quantify the total retrieval error of space-time rainfall by focusing on TOGA/COARE area (equivalent in size to a 2.5 degrees box). The same procedure can potentially be applied to other grid boxes to produce a global error field if rain statistics and measurement errors are estimated for those boxes. The accuracy of the global error field will depend on the accuracy of the rain statistics and the measurement error values used in the individual grid boxes. C1 NOAA, NESDIS Off Res & Applicat, Camp Springs, MD 20798 USA. Caelum Res Corp, Silver Spring, MD USA. RP Li, QH (reprint author), 5200 Auth Rd,703, Camp Springs, MD 20746 USA. EM qli@nesdis.noaa.gov RI Ferraro, Ralph/F-5587-2010 OI Ferraro, Ralph/0000-0002-8393-7135 NR 17 TC 14 Z9 14 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1998 VL 103 IS D10 BP 11419 EP 11427 DI 10.1029/98JD00680 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP485 UT WOS:000073758200020 ER PT J AU Erlick, C Frederick, JE AF Erlick, C Frederick, JE TI Effects of aerosols on the wavelength dependence of atmospheric transmission in the ultraviolet and visible - 1. A "single-scattering-separate" delta-Eddington model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATIVE-TRANSFER CALCULATIONS; DISCRETE ORDINATE METHOD; APPROXIMATIONS AB A modification to the conventional delta-Eddington radiative transfer scheme was implemented in order to create a simple and efficient model particularly suitable for handling the highly anisotropic scattering properties exhibited by cloud drops and aerosol particles in the atmosphere. The modification includes separating out the singly scattered radiation and applying the conventional Eddington approximation to the multiply scattered radiation alone. The singly scattered irradiance is computed analytically without approximation, preserving more of the angular dependence in the radiance than conventional two-stream style solutions. The single-scattering-separate delta-Eddington model was found to handle strong absorption in the stratosphere and the anisotropic scattering within optically thin cloud layers better than both the simple two-stream and conventional Eddington models, and to produce results similar to a 22-stream discrete ordinates model. C1 Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. RP Erlick, C (reprint author), Princeton Univ, Geophys Fluid Dynam Lab, Atmospher & Ocean Sci Program, Forrestal Campus,Route 1, Princeton, NJ 08542 USA. EM cee@gfdl.gov; frederic@sunbeam.uchicago.edu NR 16 TC 4 Z9 4 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 27 PY 1998 VL 103 IS D10 BP 11465 EP 11472 DI 10.1029/98JD00772 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP485 UT WOS:000073758200024 ER PT J AU Thompson, PE Silvestre, C Twigg, M Jernigan, G Simons, DS AF Thompson, PE Silvestre, C Twigg, M Jernigan, G Simons, DS TI Atomic hydrogen for the formation of abrupt Sb doping profiles in MBE-grown Si SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 7th International Symposium on Silicon Molecular Beam Epitaxy CY JUL 13-17, 1997 CL BANFF, CANADA SP SiGe Microsyst Inc, Natl Res Council Canada, Inst Microstruct Sci, VG Semicon, Super Vacuum Technol, Instruments SA Inc DE molecular beam epitaxy; atomic hydrogen; surfactant-assisted growth; silicon; antimony; secondary ion mass spectrometry ID MOLECULAR-BEAM EPITAXY; GE SURFACE SEGREGATION; LOW-TEMPERATURE; SI(100); IRRADIATION; DESORPTION; SILICON AB Previously, atomic hydrogen has been shown to be effective in reducing the segregation of Ge on Si(100) during solid source molecular beam epitaxy growth. In this work we have investigated atomic hydrogen to determine if it is equally effective in reducing the segregation of Sb on Si(100). Using secondary ion mass spectrometry, we demonstrated that the co-deposition of atomic hydrogen during Sb doping of Si at 500 degrees C reduced the surface segregation ratio by greater than two orders of magnitude. However, if atomic hydrogen was applied for more than 20 nm of growth, extended defects were formed. In addition, the as-grown Sb-doped layers had a low percentage of electrical activation as measured by capacitance-voltage profiling. (C) 1998 Elsevier Science S.A. All rights reserved. C1 USN, Res Lab, Washington, DC 20375 USA. NIST, Gaithersburg, MD 20899 USA. RP USN, Res Lab, Code 6812, Washington, DC 20375 USA. EM thompson@estd.nrl.navy.mil NR 20 TC 6 Z9 6 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 26 PY 1998 VL 321 BP 120 EP 124 DI 10.1016/S0040-6090(98)00459-3 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA ZZ593 UT WOS:000074745700023 ER PT J AU Unlu, MS Gokkavas, M Onat, BM Ata, E Ozbay, E Mirin, RP Knopp, KJ Bertness, KA Christensen, DH AF Unlu, MS Gokkavas, M Onat, BM Ata, E Ozbay, E Mirin, RP Knopp, KJ Bertness, KA Christensen, DH TI High bandwidth-efficiency resonant cavity enhanced Schottky photodiodes for 800-850 nm wavelength operation SO APPLIED PHYSICS LETTERS LA English DT Article ID PHOTODETECTORS AB High-speed resonant cavity enhanced Schottky photodiodes operating in 800-850 nm wavelength region are demonstrated. The devices are fabricated in the AlGaAs/GaAs material system. The Schottky contact is a semitransparent Au film which also serves as the top reflector of the Fabry-Perot cavity. The detectors exhibit a peak quantum efficiency of eta = 0.5 at lambda = 827 nm wavelength and a 3 dB bandwidth of more than 50 GHz resulting in a bandwidth-efficiency product of more than 25 GHz. (C) 1998 American Institute of Physics. C1 Boston Univ, Dept Elect & Comp Engn, Photon Ctr, Boston, MA 02215 USA. Bilkent Univ, Dept Phys, TR-06533 Ankara, Turkey. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Unlu, MS (reprint author), Boston Univ, Dept Elect & Comp Engn, Photon Ctr, Boston, MA 02215 USA. EM selim@photon.bu.edu RI Ozbay, Ekmel/B-9495-2008; Unlu, Selim/B-4244-2013; OI Onat, Bora/0000-0003-1974-0378; Mirin, Richard/0000-0002-4472-4655 NR 10 TC 34 Z9 34 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 25 PY 1998 VL 72 IS 21 BP 2727 EP 2729 PG 3 WC Physics, Applied SC Physics GA 108NZ UT WOS:000075273500034 ER PT J AU Warren, JA Boettinger, WJ Roosen, AR AF Warren, JA Boettinger, WJ Roosen, AR TI Modeling reactive wetting SO ACTA MATERIALIA LA English DT Article AB When a liquid alloy spreads on a metal substrate, interdiffusion may result in partial dissolution of the substrate and/or formation of intermetallic phases. We investigate the former case and use a diffusion,fluid flow analysis to describe the change in shape of the liquid-solid interface and the resultant motion of the triple junction along the substrate. Matching of flux boundary conditions for the liquid surface and the liquid-solid interface at the triple junction lead to an expression for the speed of spreading. The governing equations, for a drop whose height is much smaller than its width, are solved numerically for a variety of conditions. The roles of chemical driving force, liquid-solid interface energy, and angles between the various boundaries are established. During rapid spreading, large variations in curvature of the liquid-solid interface near the triple junction can lead to experimentally measured apparent angles much different from those determined by capillarity. (C) 1998 Acta Metallurgica Inc. C1 NIST, Div Met, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. NIST, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Warren, JA (reprint author), NIST, Div Met, Gaithersburg, MD 20899 USA. NR 11 TC 73 Z9 79 U1 5 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 22 PY 1998 VL 46 IS 9 BP 3247 EP 3264 DI 10.1016/S1359-6454(97)00487-4 PG 18 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA ZT576 UT WOS:000074101700027 ER PT J AU Lugez, CL Irikura, KK Jacox, ME AF Lugez, CL Irikura, KK Jacox, ME TI Experimental and ab initio study of the infrared spectra of ionic species derived from PF5, PF3, and F3PO and trapped in solid neon SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; VIBRATIONAL-SPECTRA; MATRIX-ISOLATION; ELECTRON-ATTACHMENT; ATOMS; RESOLUTION; ENERGIES; SPECTROSCOPY; FREQUENCIES AB When a Ne:PF5 or a Ne:PF3 mixture is codeposited at 5 K with a beam of neon atoms that have been excited in a microwave discharge, the infrared spectrum of the resulting solid shows a complicated pattern of new absorptions. Little fragmentation of PF5 into PF3 occurs, but several of the absorptions can be tentatively attributed to PF4. The results of extensive ab initio calculations of the vibrational spectra of the neutral, cation, and anion species of formula PFn are presented, in order to aid in the product identification. Several absorptions of PF4+, PF3+, and PF2+ are identified, with only PF3+ common to both systems. Other prominent absorptions are contributed by PF5-, PF4-, and PF3-. In all of the Ne:PF5 experiments and some of the Ne:PF3 experiments, F3PO was a major contaminant. Therefore, ab initio calculations were also conducted for most of the neutral and charged species that can result from F3PO. There is strong evidence supporting the identification of two of the vibrational fundamentals of F3PO-, and some evidence for a third. Tentative assignments are suggested for neutral and other charged species derived from F3PO. [S0021-9606(98)03320-0] C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Lugez, CL (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 65 TC 15 Z9 15 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1998 VL 108 IS 20 BP 8381 EP 8393 DI 10.1063/1.476304 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 108FQ UT WOS:000075255700010 ER PT J AU Sarmiento, JL Hughes, TMC Stouffer, RJ Manabe, S AF Sarmiento, JL Hughes, TMC Stouffer, RJ Manabe, S TI Simulated response of the ocean carbon cycle to anthropogenic climate warming SO NATURE LA English DT Article ID ATMOSPHERIC CO2; CIRCULATION; MODEL; DIOXIDE; PACIFIC; AIR AB A 1995 report(1) of the Intergovernmental Panel on Climate Change provides a set of illustrative anthropogenic CO2 emission models leading to stabilization of atmospheric CO2 concentrations ranging from 350 to 1,000 p.p.m. (refs 1-4). Ocean carbon-cycle models used in calculating these scenarios assume that oceanic circulation and biology remain unchanged through time. Here we examine the importance of this assumption by using a coupled atmosphere-ocean model of global warming(5) for the period 1765 to 2065. We find a large potential modification to the ocean carbon sink in a vast region of the Southern Ocean where increased rainfall leads to surface freshening and increased stratification(6). The increased stratification reduces the downward flux of carbon and the loss of heat to the atmosphere, both of which decrease the oceanic uptake of anthropogenic CO2 relative to a constant-climate control scenario. Changes in the formation, transport and cycling of biological material may counteract the reduced uptake, but the response of the biological community to the climate change is difficult to predict on present understanding. Our simulation suggests that such physical and biological changes might already be occurring, and that they could substantially affect the ocean carbon sink over the next few decades. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Bermuda Biol Stn Res, Ferry Reach, Bermuda. RP Sarmiento, JL (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, POB CN710, Princeton, NJ 08544 USA. EM jls@splash.princeton.edu NR 27 TC 502 Z9 524 U1 19 U2 131 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 21 PY 1998 VL 393 IS 6682 BP 245 EP 249 DI 10.1038/30455 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZP513 UT WOS:000073761000046 ER PT J AU Churnside, JH Tatarskii, VV Wilson, JJ AF Churnside, JH Tatarskii, VV Wilson, JJ TI Oceanographic lidar attenuation coefficients and signal fluctuations measured from a ship in the Southern California Bight SO APPLIED OPTICS LA English DT Article ID OPTICAL-PROPERTIES; AIRBORNE LIDAR; OCEAN; PERFORMANCE; SCATTERING; AIRCRAFT; SYSTEM AB We measured the attenuation coefficient of the National Oceanic and Atmospheric Administration lidar from a ship in the Southern California Eight in September 1995. The region from approximately 5 to 30 m in depth was covered. The laser was linearly polarized, and the receiver was operated with the same polarization and the orthogonal polarization. The measured values were between 0.08 and 0.12 m(-1) and were highly correlated with in situ measurements of the beam attenuation coefficient. Fluctuations of the lidar signal were found to be induced primarily by surface waves whose wavelengths are approximately three times the lidar spot size at the surface. (C) 1998 Optical Society of America. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Churnside, JH (reprint author), NOAA, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. RI Churnside, James/H-4873-2013 NR 23 TC 21 Z9 23 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1998 VL 37 IS 15 BP 3105 EP 3112 DI 10.1364/AO.37.003105 PG 8 WC Optics SC Optics GA ZM902 UT WOS:000073587800002 PM 18273257 ER PT J AU Corwin, KL Lu, ZT Hand, CF Epstein, RJ Wieman, CE AF Corwin, KL Lu, ZT Hand, CF Epstein, RJ Wieman, CE TI Frequency-stabilized diode laser with the Zeeman shift in an atomic vapor SO APPLIED OPTICS LA English DT Article AB We demonstrate a robust method of stabilizing a diode laser frequency to an atomic transition. This technique employs the Zeeman shift to generate an antisymmetric signal about a Doppler-broadened atomic resonance, and therefore offers a large recapture range as well as high stability. The frequency of a 780-nm diode laser. stabilized to such a signal. in Rb, drifted less than 0.5 MHz peak-peak (1 part in 10(9)) in 38 h. This tunable frequency lock can he constructed inexpensively, requires little laser power, rarely loses lock, and can be extended to other wavelengths by use of different atomic species. (C) 1998 Optical Society of America. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Corwin, KL (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Corwin, Kristan/A-1331-2013 NR 5 TC 232 Z9 247 U1 8 U2 37 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1998 VL 37 IS 15 BP 3295 EP 3298 DI 10.1364/AO.37.003295 PG 4 WC Optics SC Optics GA ZM902 UT WOS:000073587800031 PM 18273286 ER PT J AU Gutman, G Ignatov, A AF Gutman, G Ignatov, A TI The derivation of the green vegetation fraction from NOAA/AVHRR data for use in numerical weather prediction models SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID LEAF-AREA INDEX; HIGH-RESOLUTION RADIOMETER; SATELLITE DATA; SURFACE-TEMPERATURE; CLIMATE-MODELS; GLOBAL DATA; DATA SET; COVER; SENSITIVITY; PARAMETERS AB Fraction of green vegetation, f(g), and green leaf area index, L-g, are needed as a regular space-time gridded input to evapotranspiration schemes in the two National Weather Service (NWS) numerical prediction models-regional Eta and global medium range forecast. This study explores the potential of deriving these two variables from the NOAA Advanced Very High Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI) data. Obviously, one NDVI measurement does not allow simultaneous derivation of both vegetation variables. Simple models of a satellite pixel are used to illustrate the ambiguity resulting from a combination of the unknown horizontal (f(g)) and vertical (L-g) densities. We argue that for NOAA AVHRR data sets based on observations with a spatial resolution of a few kilometres the most appropriate way to resolve this ambiguity is to assume that the vegetated part of a pixel is covered by dense vegetation (i.e., its leaf area index is high), and to calculate f(g) = (NDVI-NDVIo)/(NDVIinfinity-NDVIo), where NDVIo (bare soil) and NDVIinfinity (dense vegetation) are specified as global constants independent of vegetation/soil type. Global (0.15 degrees)(2) spatial resolution monthly maps of f(g) were produced from a 5-year NDVI climatology and incorporated in the NWS models. As a result, the model surface fluxes were improved. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. RP Gutman, G (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, World Weather Bldg, Washington, DC 20233 USA. RI Ignatov, Alexander/F-5594-2010 OI Ignatov, Alexander/0000-0002-7463-5944 NR 38 TC 489 Z9 696 U1 11 U2 72 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 1998 VL 19 IS 8 BP 1533 EP 1543 DI 10.1080/014311698215333 PG 11 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA ZW676 UT WOS:000074435500006 ER PT J AU McConnell, JR Bales, RC Stewart, RW Thompson, AM Albert, MR Ramos, R AF McConnell, JR Bales, RC Stewart, RW Thompson, AM Albert, MR Ramos, R TI Physically based modelling of atmosphere-to-snow-to-firn transfer of H2O2 at South Pole SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ICE CORES; AIR; DEPOSITION; GREENLAND AB Quantitative interpretation of ice core chemical records requires a detailed understanding of the transfer processes that relate atmospheric concentrations to those in the snow, firn, and ice. A unique, 2 year set of year-round surface snow samples at South Pole and snow pits, with associated accumulation histories, were used to test a physically based model for atmosphere-to-firn transfer of H2O2. The model, which extends our previous transfer modeling at South Pole into the snowpack, is based on the advection-dispersion equation and spherical diffusion within representative snow grains. Required physical characteristics of the snowpack, such as snow temperature and ventilation, were estimated independently using established physical models. The surface snow samples and related model simulations show that there is a repeatable annual cycle in H2O2 in the surface snow at South Pale. It peaks in early spring, and surface snow concentration is primarily determined by atmospheric concentration and temperature, with some dependence on grain size. The snow pits and associated model simulations point out the impor tance of accumulation timing and annual accumulation rate in understanding the deposition and preservation of H2O2 and delta(18)O at South Pole. Long-term snowpack simulations suggest that the firn continues to lose H2O2 to the atmosphere for at least 10-12 years (similar to 3 m) after burial at current South Pole temperatures and accumulation rates. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Cold Reg Res & Engn Lab, Hanover, NH 03755 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP McConnell, JR (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. EM joe@hwr.arizona.edu RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 31 TC 54 Z9 54 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1998 VL 103 IS D9 BP 10561 EP 10570 DI 10.1029/98JD00460 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZN676 UT WOS:000073670500001 ER PT J AU Andronache, C Chameides, WL AF Andronache, C Chameides, WL TI Interactions between sulfur and soot emissions from aircraft and their role in contrail formation 2. Development SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID JET AIRCRAFT; NUCLEATION; AEROSOLS; PLUME; STRATOSPHERE; CONDENSATION; PARTICLES; DROPLETS; CIRRUS; FUELS AB A numerical box model of the time evolution of key gaseous and aerosol species in an expanding plume of a subsonic aircraft is developed to investigate the effects of aircraft emissions on the characteristics of contrails. The model simulates the formation and growth of new particles from H2SO4 and H2O and the growth of activated soot particles. Coagulation, dilution, and interaction with gaseous species are included. The evidence of contrail formation is determined by the condensed water concentration, using a visibility threshold of 10(-5) kg m(-3). The model simulates formation of large concentrations of H2SO4-H2O particles with radii in the range similar to 1-10 nm. The number concentration and the rate of growth of these particles is dependent on the sulfur emissions. We find that for a given initial concentration of soot particles and ambient conditions the sensitivity of contrail properties to fuel sulfur content is small for typical emission indices (0.1-1 g kg(-1)). For larger sulfur emissions and favorable conversion of sulfur into H2SO4 the calculations show a slight impact of sulfur on contrail properties, such as lifetime, onset, and threshold temperature. The magnitude of this influence is generally smaller than the variations caused by uncertainties in the mass accommodation coefficient of sulfur species on soot surface, entrainment rate of ambient air into the plume, soot emissions, and atmosphere parameters at flight altitude. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Andronache, C (reprint author), Princeton Univ, GFDL, NOAA, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. EM cna@gfdl.gov; wcham@eas.gatech.edu RI Andronache, Constantin/C-4431-2011 OI Andronache, Constantin/0000-0001-5375-7056 NR 45 TC 5 Z9 5 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1998 VL 103 IS D9 BP 10787 EP 10802 DI 10.1029/98JD00173 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZN676 UT WOS:000073670500015 ER PT J AU Ikkai, F Shibayama, M Han, CC AF Ikkai, F Shibayama, M Han, CC TI Effect of degree of cross-linking on spatial inhomogeneity in charged gels. 2. Small-angle neutron scattering study SO MACROMOLECULES LA English DT Article ID POLY(N-ISOPROPYLACRYLAMIDE-CO-ACRYLIC ACID) GELS; DYNAMIC LIGHT-SCATTERING; POLYMER GELS; POLYACRYLAMIDE GELS; FLUCTUATIONS; NETWORKS AB The structural inhomogeneities in a weakly charged gel consisting of (N-isopropylacrylamide-co-acrylic acid) (NIPA-AAc) have been investigated by small-angle neutron scattering (SANS) as a function of cross-linking density (CD) and temperature. The CD and temperature dependence of the scattered intensity profiles, I(q), indicated the presence of an anomalous CD dependence of the scattering intensity, where q is the magnitude of the scattering vector. At temperatures below 42 degrees C, I(q) was a monotonically decreasing function of q and increased with CD at q less than or equal to 0.08 Angstrom(-1). However, above 45 degrees C, I(q) started to have a distinct peak around q = 0.02 Angstrom(-1) and the CD dependence of I(q) became classifiable into two regimes depending on temperature; one where I(q) increases with CD, and the other where I(q) decreases with CD. Since a similar phenomenon, called "inversion", has already been observed by light scattering, it is concluded here that the inversion is a universal phenomenon observed in a wide range of the q space from 10(-4) to 10(-2) Angstrom(-1). The physical meaning of this inversion is discussed on the basis of the Rabin-Panyukov theory proposed for weakly charged gels. C1 Kyoto Inst Technol, Dept Polymer Sci & Engn, Sakyo Ku, Kyoto 6068585, Japan. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Shibayama, M (reprint author), Kyoto Inst Technol, Dept Polymer Sci & Engn, Sakyo Ku, Kyoto 6068585, Japan. RI Shibayama, Mitsuhiro/E-1646-2015 OI Shibayama, Mitsuhiro/0000-0002-8683-5070 NR 27 TC 27 Z9 27 U1 2 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 19 PY 1998 VL 31 IS 10 BP 3275 EP 3281 DI 10.1021/ma971468y PG 7 WC Polymer Science SC Polymer Science GA ZP498 UT WOS:000073759500018 ER PT J AU Meyer, A Wuttke, J Petry, W Randl, OG Schober, H AF Meyer, A Wuttke, J Petry, W Randl, OG Schober, H TI Slow motion in a metallic liquid SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODE-COUPLING-THEORY; NEUTRON-SPIN-ECHO; GLASS-TRANSITION; SUPERCOOLED LIQUIDS; VISCOUS GLYCEROL; LIGHT-SCATTERING; RELAXATION; DYNAMICS; DIFFUSION; ZR41.2TI13.8CU12.5NI10.0BE22.5 AB Liquid Zr46.8Ti8.2Cu7.5Ni10Be27.5 has been studied by quasielastic neutron scattering. The microscopic dynamics of this bulk glass forming alloy deviates qualitatively from simple metallic liquids; it shows two-step structural relaxation like other Liquids in their supercooled state. Unexpectedly for a nonfragile system, fast beta relaxation is in full accord with the mode-coupling theory of the liquid to glass transition. The long-time alpha relaxation suggests failure of the Stokes-Einstein relation. C1 Tech Univ Munich, Dept Phys, D-85747 Garching, Germany. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Meyer, A (reprint author), NIST, Gaithersburg, MD 20899 USA. RI Wuttke, Joachim/C-1142-2008; Meyer, Andreas/F-6260-2013; Petry, Winfried/K-4998-2016; OI Petry, Winfried/0000-0001-5208-7070; Wuttke, Joachim/0000-0002-4028-1447 NR 40 TC 76 Z9 78 U1 3 U2 21 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4454 EP 4457 DI 10.1103/PhysRevLett.80.4454 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900024 ER PT J AU Benedict, LX Shirley, EL Bohn, RB AF Benedict, LX Shirley, EL Bohn, RB TI Optical absorption of insulators and the electron-hole interaction: An ab initio calculation SO PHYSICAL REVIEW LETTERS LA English DT Article ID SEMICONDUCTORS; SPECTRUM AB We present a computationally efficient scheme to calculate the optical absorption of insulators from first principles, including the electron-hole interaction. Excited states of the solid are chosen to consist of single electron-hole pairs. The electron-hole interaction is statically screened using a model dielectric function. Only two pieces of input are required, the crystal structure of the material and the macroscopic dielectric constant. We apply this scheme to two wide-gap insulators, LiF and MgO, and obtain excellent agreement with experimental measurements of their UV reflectance spectra. C1 NIST, Opt Technol Div, Phys Lab, Gaithersburg, MD 20899 USA. NIST, Informat Technol Lab, High Performance Syst & Serv Div, Gaithersburg, MD 20899 USA. RP Benedict, LX (reprint author), NIST, Opt Technol Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 19 TC 298 Z9 298 U1 2 U2 25 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4514 EP 4517 DI 10.1103/PhysRevLett.80.4514 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900039 ER PT J AU Keller, MW Martinis, JM Kautz, RL AF Keller, MW Martinis, JM Kautz, RL TI Rare errors in a well-characterized electron pump: Comparison of experiment and theory SO PHYSICAL REVIEW LETTERS LA English DT Article ID ACCURACY AB By measuring each junction of an electron pump in a single electron box configuration, we determine all quantities needed to test the standard theory of pumping error and leakage. Background charges are determined with an imprecision of +/-0.01e. Electron temperature is measured to 40 mK. Measured charging energies show all junctions have nearly the same capacitance. We find agreement with theory at 140 mK, but a disagreement of many orders of magnitude at 30 mK. We suggest that the excess error and leakage at 40 mK are due to photon-assisted cotunneling processes not included in the standard theory. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Natl Inst Stand & Technol, Boulder, CO 80303 USA. NR 15 TC 54 Z9 54 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4530 EP 4533 DI 10.1103/PhysRevLett.80.4530 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900043 ER PT J AU Lynn, JW Vasiliu-Doloc, L Subramanian, MA AF Lynn, JW Vasiliu-Doloc, L Subramanian, MA TI Spin dynamics of the magnetoresistive pyrochlore Tl2Mn2O7 SO PHYSICAL REVIEW LETTERS LA English DT Article ID DOUBLE-EXCHANGE; FERROMAGNET AB Neutron scattering has been used to study the magnetic order and spin dynamics of the colossal magnetoresistive pyrochlore Tl2Mn2O7. On cooling from the paramagnetic state, magnetic correlations develop and appear to diverge at T-c (123 K). In the ferromagnetic phase well defined spin waves are observed, with a gapless (Delta < 0.04 meV) dispersion relation E = Dq(2) as expected for an ideal isotropic ferromagnet. As T --> T-c from low T, the spin waves renormalize, but no significant central diffusive component to the fluctuation spectrum is observed in stark contrast to the La1-x(Ca, Ba,Sr)(x)MnO3 system. These results argue strongly that the mechanism responsible for the magnetoresistive effect has a different origin in these two classes of materials. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. RP Lynn, JW (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 28 TC 31 Z9 31 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 18 PY 1998 VL 80 IS 20 BP 4582 EP 4585 DI 10.1103/PhysRevLett.80.4582 PG 4 WC Physics, Multidisciplinary SC Physics GA ZN308 UT WOS:000073632900056 ER PT J AU Salas, JP Deprit, A Ferrer, S Lanchares, V Palacian, J AF Salas, JP Deprit, A Ferrer, S Lanchares, V Palacian, J TI Two pitchfork bifurcations in the polar quadratic Zeeman-Stark effect SO PHYSICS LETTERS A LA English DT Article DE Zeeman effect; Stark effect; equilibria; bifurcation; periodic orbits ID RYDBERG ATOMS; MAGNETIC-FIELDS; ELECTRIC-FIELDS; HYDROGEN-ATOM; DIAMAGNETIC MANIFOLD; PARALLEL; LITHIUM; STATES; ORBITS AB In the framework of classical mechanics, a study of the hydrogen atom in the presence of parallel electric and magnetic fields is presented when the magnetic quantum number m is zero. By means of perturbation methods and Poincare surfaces of section, the existence of the three states experimentally detected by Cacciani et al. (the so-called I, II, and III Cacciani's states), their energy extensions, their evolution and their disappearance are explained as a result of two pitchfork bifurcations. (C) 1998 Elsevier Science B.V. C1 Univ La Rioja, Area Fis Aplicada, Logrono 26004, Spain. NIST, Gaithersburg, MD 20899 USA. Univ Murcia, Dept Matemat Aplicada, Cartagena 30203, Spain. Univ La Rioja, Dept Matemat & Computac, Logrono 26004, Spain. Univ Publ Navarra, Dept Matemat & Informat, Pamplona 31006, Spain. RP Salas, JP (reprint author), Univ La Rioja, Area Fis Aplicada, Logrono 26004, Spain. RI Lanchares, Victor/B-4688-2010; OI Lanchares, Victor/0000-0003-3228-9382; Salas, J. Pablo/0000-0003-2009-8247 NR 23 TC 15 Z9 17 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD MAY 18 PY 1998 VL 242 IS 1-2 BP 83 EP 93 DI 10.1016/S0375-9601(98)00116-9 PG 11 WC Physics, Multidisciplinary SC Physics GA ZP071 UT WOS:000073713600014 ER PT J AU Mace, GG Jakob, C Moran, KP AF Mace, GG Jakob, C Moran, KP TI Validation of hydrometeor occurrence predicted by the ECMWF model using millimeter wave radar data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLOUD AB Validation of hydrometeor prediction by global models is an important issue as it pertains to the accuracy of climate predictions. In this study we use data from a continuously operating millimeter wave radar at a research site in north central Oklahoma, USA to validate output from the operational ECMWF forecast model. We demonstrate that the ECMWF model shows good overall skill at predicting the vertical distribution of the clouds and precipitation that occurred over this site during winter 1997. However, we also show that the model tended to predict the onset of deep cloud events too soon, made the layers too deep and predicted dissipation somewhat later than observed. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NOAA, Environm Res Lab, Boulder, CO 80303 USA. RP Mace, GG (reprint author), Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. RI Jakob, Christian/A-1082-2010 OI Jakob, Christian/0000-0002-5012-3207 NR 13 TC 64 Z9 65 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1998 VL 25 IS 10 BP 1645 EP 1648 DI 10.1029/98GL00845 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZN248 UT WOS:000073626900027 ER PT J AU Helfrich, KR Joyce, TM Cannon, GA Harrington, SA Pashinski, DJ AF Helfrich, KR Joyce, TM Cannon, GA Harrington, SA Pashinski, DJ TI Mean hydrographic and velocity sections near Pipe Organ vent at Juan de Fuca Ridge SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HYDROTHERMAL PLUME AB A composite cross-ridge hydrographic and velocity section near the Pipe Organ vent site on the Juan de Fuca Ridge is presented. The hydrographic section is composed of surveys obtained from 1990 to 1994. The potential temperature field shows pronounced downward sloping of the isotherms below 1.9 degrees (centered at about 150 m above the bottom) on either side of the ridge crest. The horizontal scale is about 2 km, comparable to the local Rossby deformation radius. The maximum potential temperature anomaly is greater than 0.03 degrees C. Significant light attenuation anomalies are also present. The mean along-ridge velocity section is constructed from the records of 85 current meters. The mean flow is southward at and to the east of the vent and northward to the west. Largest velocities occur at the depth of the neutrally buoyant plume. The cross-ridge shear is thus anti-cyclonic with a characteristic value of -0.05 f. Geostrophic velocity fields obtained from the density section differ significantly from the field produced from the current meter data. An estimate of the net mean flux of anomalous heat gives 780 (+/-400) MW to the south. C1 Woods Hole Oceanog Inst, Dept Phys Oceanog, Woods Hole, MA 02543 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. MIT WHOI, Joint Program Oceanog, Woods Hole, MA 02543 USA. RP Helfrich, KR (reprint author), Woods Hole Oceanog Inst, Dept Phys Oceanog, 360 Woods Hole Rd,MS 21, Woods Hole, MA 02543 USA. NR 7 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1998 VL 25 IS 10 BP 1737 EP 1740 DI 10.1029/98GL01308 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZN248 UT WOS:000073626900050 ER PT J AU Joyce, TM Cannon, GA Pashinski, D Helfrich, KR Harrington, SA AF Joyce, TM Cannon, GA Pashinski, D Helfrich, KR Harrington, SA TI Vertical and temporal vorticity observations at Juan de Fuca Ridge: hydrothermal signatures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BAROCLINIC VORTEX; PACIFIC-OCEAN; PLUMES AB Moored current measurements made from April 1994 to June 1995 reveal the vertical and temporal structure of the vorticity over the northern segment of the Juan de Fuca Ridge. At a depth of 2100m, near the thermal and particle maximum associated with the neutrally buoyant hydrothermal plume, the relative vorticity is anticyclonic with a mean value of nearly -0.09f, with variability of the same magnitude. This arises from cross-ridge shear in the horizontal currents at this level. In the vertical, the anticyclonic shear has a peak value at plume level decreasing in magnitude both upward and downward from depths of 2100-2150m. As the bottom is approached, the transverse shear changes sign with cyclonic values of up to 0.09f below 2250m depth. This vorticity signature is suggestive of dynamics of a line source of buoyant fluid entering the plume at its neutral density horizon and not due to individual point sources. C1 Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Joyce, TM (reprint author), Woods Hole Oceanog Inst, 360 Woods Hole Rd,MS 21, Woods Hole, MA 02543 USA. EM tjoyce@whoi.edu; cannon@pmel.noaa.gov; pashinski@pmel.noaa.gov; khelfrich@whoi.edu; sharrington@whoi.edu NR 13 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1998 VL 25 IS 10 BP 1741 EP 1744 DI 10.1029/98GL01309 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZN248 UT WOS:000073626900051 ER PT J AU Berkeland, DJ Miller, JD Bergquist, JC Itano, WM Wineland, DJ AF Berkeland, DJ Miller, JD Bergquist, JC Itano, WM Wineland, DJ TI Minimization of ion micromotion in a Paul trap SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LASER-COOLED IONS; SINGLE; SPECTROSCOPY; RADIATION; CRYSTALS; SHIFT AB Micromotion of ions in Paul traps has several adverse effects, including alterations of atomic transition line shapes, significant second-order Doppler shifts in high-accuracy studies, and limited confinement time in the absence of cooling. The ac electric field that causes the micromotion may also induce significant Stark shifts in atomic transitions. We describe three methods of detecting micromotion. The first relies on the change of the average ion position as the trap potentials are changed. The second monitors the amplitude of the sidebands of a narrow atomic transition, caused by the first-order Doppler shift due to the micromotion. The last technique detects the Doppler shift induced modulation of the fluorescence rate of a broad atomic transition. We discuss the detection sensitivity of each method to Doppler and Stark shifts, and show experimental results using the last technique. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM dana.berkeland@boulder.nist.gov NR 27 TC 310 Z9 312 U1 7 U2 53 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1998 VL 83 IS 10 BP 5025 EP 5033 DI 10.1063/1.367318 PG 9 WC Physics, Applied SC Physics GA ZP639 UT WOS:000073773600002 ER PT J AU Asher, WE Wanninkhof, R AF Asher, WE Wanninkhof, R TI The effect of bubble-mediated gas transfer on purposeful dual-gaseous tracer experiments SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SULFUR-HEXAFLUORIDE; BOMB RADIOCARBON; WATER; SEA; FLUX; INTERFACE; SEAWATER; EXCHANGE; WAVES; OCEAN AB For air-water gas exchange across unbroken surfaces, the only gas-dependent parameter affecting the transfer velocity is the molecular diffusivity of the transferring species. in contrast, bubble-mediated transfer processes can cause the transfer velocity to depend on both molecular diffusivity and aqueous-phase solubility. This can complicate the analysis of data from dual gaseous tracer gas transfer experiments. Bubble effects also complicate the estimation of transfer velocities for other gases from the transfer velocity calculated using the dual-tracer data. Herein a method for incorporating the effects of bubble-mediated gas transfer processes on the transfer velocity is presented. This new procedure is used to analyze the data from two recent dual-tracer gas transfer experiments. Transfer velocities that include the effect of bubbles are calculated using the data from two previous oceanic dual-gaseous tracer experiments. Comparing these transfer velocities with transfer velocities calculated by neglecting the effect of bubbles shows that bubble-mediated transfer increased the transfer velocity of helium 3 by 5% at a wind speed of 10.6 m s(-1). However, when using the transfer velocities for helium 3 to calculate transfer velocities for carbon dioxide under the same conditions, including the effect of bubbles decreases the transfer velocity of carbon dioxide by 18%. This shows that bubble-mediated transfer does not have a large effect on the analysis of dual-tracer data, but it is important in relating transfer velocities determined using helium 3 and sulfur hexafluoride to transfer velocities of more soluble gases at wind speeds above 10 m s(-1). C1 Univ Washington, Coll Ocean & Fishery Sci, Appl Phys Lab, Seattle, WA 98105 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Asher, WE (reprint author), Univ Washington, Coll Ocean & Fishery Sci, Appl Phys Lab, 1013 NE 40th St, Seattle, WA 98105 USA. EM asher@apl.washington.edu; wanninkh@aoml.noaa.gov NR 24 TC 84 Z9 84 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 15 PY 1998 VL 103 IS C5 BP 10555 EP 10560 DI 10.1029/98JC00245 PG 6 WC Oceanography SC Oceanography GA ZN319 UT WOS:000073634000022 ER PT J AU Lu, CG Browning, GL AF Lu, CG Browning, GL TI The impact of observational errors on objective analyses SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ANALYSIS SCHEME; SYSTEMS AB The impact of observational errors on objective analyses is investigated with mathematical analyses, analytical examples, and real data experiments. Cases with observational errors at one or more stations are considered. It is found that in the presence of observational errors, the analysis error in an objective analysis scheme generally consists of two parts: the signal fitting error and the noise contamination error. Although every objective analysis scheme has its own procedure(s) to control the two errors, the procedures to suppress the noise contamination error in one and two dimensions are shown to be relatively ineffective. It is shown that the extension of an objective analysis method to more dimensions significantly reduces the noise contamination. Based on these results, higher dimensional versions of the least squares polynomial fitting (LSPF) methods and the Barnes scheme are examined. In both analytic and real data experiments, the 3D and 4D LSPF methods and the 3D Barnes scheme show an enhanced ability to filter observational noise. C1 NOAA, ERL, Forecast Syst Lab, Boulder, CO 80303 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Lu, CG (reprint author), NOAA, ERL, Forecast Syst Lab, 325 Broadway, Boulder, CO 80303 USA. NR 28 TC 4 Z9 6 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 15 PY 1998 VL 55 IS 10 BP 1791 EP 1807 DI 10.1175/1520-0469(1998)055<1791:TIOOEO>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZN646 UT WOS:000073667500004 ER PT J AU Robins, LH Tuchman, JA AF Robins, LH Tuchman, JA TI Photoluminescence studies of Sm2+ in the stimulable phosphor SrS : Eu,Sm SO PHYSICAL REVIEW B LA English DT Article ID MGS; LUMINESCENCE; CAS AB The doubly rare-earth doped phosphor SrS:Eu,Sm is representative of a class of stimulable phosphors that may find application in optical data storage and related areas of photonic technology. The infrared photoluminescence (PL) from the Sm2+ ions is a potentially useful probe of the "written" state of this phosphor, i.e., the right-hand side of the charge-transfer reaction (Eu2++Sm(3+)reversible arrow Eu3++Sm2+). In the present study, several properties of the Sm2+ PL from bulk ceramic SrS:Eu,Sm were examined, including the emission spectrum, temperature dependence from 14 to 300 K, electron-phonon coupling, excitation spectrum, and excitation intensity dependence. The full width at half maximum of the PL emission spectrum, W(T), was found to increase with temperature in a manner consistent with a linear electron-phonon coupling model, W(T) = W-o[tanh(Omega/(2k(B)T))](-1/2), with W-o=0.190 eV and coupled phonon energy Omega=0.026 eV. Periodic oscillations in the PL spectrum at T<60 K provide direct evidence for coupling to two phonon modes, with phonon energies Omega(1) = 0.0155 eV and Omega(2) = 0.028 eV. The peak of the emission spectrum occurs at 0.709 eV at 14 K and increases with temperature at a rate 1.9x10(-4) eV/K. The electron-phonon coupling model predicts that the corresponding optical absorption peak, which is anti-Stokes shifted relative to the PL peak, should occur at 1.17 eV at low temperature, or 1.23 eV at room temperature. Previous measurements of the charge-transfer excitation spectrum in SrS:Eu,Sm showed a peak at 1.25 eV, in good agreement with the model prediction. The PL excitation spectrum from 1.7 to 6.2 eV was measured at T=14 K. Excitation peaks were observed at 2.08 eV, ascribed to absorption to a higher excited Sm2+ state; at 2.65 eV, ascribed to Eu2+ absorption followed by Eu-->Sm charge transfer; at 2.92 eV; and at 4.49 eV, ascribed to interband excitation of the SrS. [S0163-1829(98)03819-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Opex Commun Corp, Rockville, MD 20850 USA. RP Robins, LH (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 19 TC 37 Z9 38 U1 0 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1998 VL 57 IS 19 BP 12094 EP 12103 DI 10.1103/PhysRevB.57.12094 PG 10 WC Physics, Condensed Matter SC Physics GA ZP518 UT WOS:000073761500050 ER PT J AU Lupton, JE Baker, ET Garfield, N Massoth, GJ Feely, RA Cowen, JP Greene, RR Rago, TA AF Lupton, JE Baker, ET Garfield, N Massoth, GJ Feely, RA Cowen, JP Greene, RR Rago, TA TI Tracking the evolution of a hydrothermal event plume with a RAFOS neutrally buoyant drifter SO SCIENCE LA English DT Article ID DE-FUCA RIDGE; 1993 COAXIAL EVENT; BAROCLINIC VORTEX; CLEFT SEGMENT; VENT PLUMES; JUAN; MANGANESE; SEA; MEGAPLUMES; MODEL AB The migration and evolution of a deep ocean hydrothermal event plume were tracked with a neutrally buoyant RAFOS float. The float remained entrained in the plume for 60 days, and the plume vorticity was calculated directly from the anticyclonic motion of the float. Concentrations of suspended particles, particulate iron, and dissolved manganese in the plume did not decay significantly during the 60 days, which indicates that event plumes would be easily detectable a year after formation. C1 NOAA, Pacific Marine Environm Lab, Newport, OR 97365 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Lupton, JE (reprint author), NOAA, Pacific Marine Environm Lab, Newport, OR 97365 USA. NR 34 TC 27 Z9 27 U1 0 U2 5 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 15 PY 1998 VL 280 IS 5366 BP 1052 EP 1055 DI 10.1126/science.280.5366.1052 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ZN615 UT WOS:000073663600039 ER PT J AU Ott, AK Casey, SM Leone, SR AF Ott, AK Casey, SM Leone, SR TI Arsenic desorption kinetics from Si(100) SO SURFACE SCIENCE LA English DT Article DE arsenic; desorption; ionization mass spectroscopy; laser single photon; scattering; silicon ID SURFACES; MICROSCOPY; SI(001); DIFFRACTION; GENERATION; RADIATION; KRYPTON; XENON AB The Buses of As-4, As-2, and As scattered and desorbed from a Si (100) substrate exposed to an incident flux of As-4 were measured with single-photon ionization time-of-flight mass spectrometry (SPI-TOFMS) as a fullction of the Si substrate temperature and the incident arsenic Bus. At Si substrate temperatures > 1050 K, a flux of As atoms is detected. Analysis of the time-dependent transient behavior of the desorbed As atom flux reveals first-order desorption kinetics. The activation energy for desorption is 1.64+/- .05 eV with a pre-exponential factor of (7.8+/- 3.4) x 10(-7) s(-1). The incident As-4 flux dependence of the desorbing flux of As atoms suggests that desorption of atoms occurs from Limited sites on the surface. such as step edges or defects, The desorption kinetics of As-2 from the Si(100) surface was found to be more complex as a result of both the kinetic order of the process and a decrease in the steady-state arsenic coverage. At substrate temperatures greater than 1050 K, the desorption of As-2 from the surface is rapid and depends only on the incident As-4 flux leaving little or no steud-state arsenic coverage on the Si(100) terraces. The scattered As-2 flux from the surface decreases with increased surface temperature, since incident As-4 molecules react on the Si surface to produce both the As-2 and As atom desorption channels, (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 19 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 15 PY 1998 VL 405 IS 2-3 BP 228 EP 237 DI 10.1016/S0039-6028(98)00063-6 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZX442 UT WOS:000074516200021 ER PT J AU Egelhoff, WF AF Egelhoff, WF TI Fluorine as a surfactant in the deposition of a monolayer of Fe on Cu (100) SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 17th European Conference on Surface Science CY SEP 16-19, 1997 CL ENSCHEDE, NETHERLANDS DE copper; epitaxy; fluorine; iron; photoelectron diffraction ID BY-LAYER GROWTH; ELECTRON-STIMULATED DESORPTION; MOLECULAR-BEAM EPITAXY; MEDIATED GROWTH; ADSORBED GASES; CU(100); FILMS; GE; SUPERLATTICES; MORPHOLOGY AB The deposition of a monolayer of Fe on Cu(100) at 300 K is well known to field a surface that is far from a perfect monolayer of Fe. Both interdiffusion and agglomeration of Fe occur. In the present work, it is found that if the Cu(100) surface is saturated with F atoms prior to the deposition of Fe, most of the interdiffusion and agglomeration of the Fe is suppressed. The surface can then be cooled to 100 K, and the F removed by electron stimulated desorption. This procedure leaves the Fe atoms at the surface frozen in place. The Fe monolayer is not structurally perfect (the LEED spots are broadened), but it appears to be much improved over any other known technique for producing Fe monolayers on Cu(100). A monolayer of high-surface-free-energy metal on low-surface-free-energy substrate may be viewed as a fundamental building block for atomic engineering of novel superlattices. The work reported here is a promising new approach to achieving that end. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Magnet Mat Grp, Gaithersburg, MD 20899 USA. RP Egelhoff, WF (reprint author), Natl Inst Stand & Technol, Magnet Mat Grp, Gaithersburg, MD 20899 USA. EM egelhoff@nist.gov NR 30 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 15 PY 1998 VL 402 IS 1-3 BP 32 EP 36 DI 10.1016/S0039-6028(98)00029-6 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA ZY342 UT WOS:000074610800005 ER PT J AU Migdalek, J Kim, YK AF Migdalek, J Kim, YK TI Core polarization and oscillator strength ratio anomaly in potassium, rubidium and caesium SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID SPECTRA; PHOTOABSORPTION; TRANSITIONS; CESIUM; ATOMS AB The problem of the anomalous ratios of the oscillator strengths in the heavy alkali principal series, though known for almost 70 years, still attracts the attention of both theorists and experimentalists. Our present fully relativistic model potential calculations demonstrate that the spin-orbit interaction cannot be solely responsible for the observed anomalies in potassium, rubidium and caesium and that they result from the interplay of spin-orbit interaction, core valence electron correlation (core polarization) and cancellation observed in transition integrals. The role of core polarization is carefully studied. It is shown that in the case of the empirically adjusted model potential the most important correction is not the inclusion of polarization potential but the allowance made for the additional induced dipole moment in the dipole moment operator of transition. Also the form employed to represent the correction to the dipole moment is important, if one wishes to avoid any adjustment in core polarization corrections. It is also shown that the employment of J-dependent effective model potentials (J = total angular momentum) is essential in reproducing relativistic effects in f-value ratios. C1 Cracow Pedag Univ, Inst Phys & Comp Sci, PL-30084 Krakow, Poland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Cracow Pedag Univ, Inst Phys & Comp Sci, PL-30084 Krakow, Poland. NR 31 TC 24 Z9 26 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 EI 1361-6455 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 14 PY 1998 VL 31 IS 9 BP 1947 EP 1960 DI 10.1088/0953-4075/31/9/011 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA ZQ091 UT WOS:000073820500011 ER PT J AU Markelz, AG Asmar, NG Gwinn, EG Brar, B AF Markelz, AG Asmar, NG Gwinn, EG Brar, B TI Relaxation times in InAs/AlSb quantum wells SO APPLIED PHYSICS LETTERS LA English DT Article ID HOT-ELECTRON TRANSPORT; ENERGY RELAXATION; TEMPERATURE; GASES AB We have measured energy relaxation and longitudinal-optical (LO) phonon emission times in modulation-doped InAs quantum wells driven by high dc fields, and by intense ac fields at frequencies from 0.49 to 0.66 terahertz. We find that for electron temperatures between 50 and 200 K, LO phonon emission dominates energy relaxation. We determine a large net LO phonon emission time, indicating a strong LO phonon bottleneck both in high dc and in intense terahertz fields. (C) 1998 American Institute of Physics. [S0003-6951(98)02619-9]. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. NIST, Gaithersburg, MD 20899 USA. PowerTV Inc, Cupertino, CA 95014 USA. Texas Instruments Inc, Dallas, TX 75222 USA. RP Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. OI Markelz, Andrea/0000-0003-0443-4319 NR 18 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 11 PY 1998 VL 72 IS 19 BP 2439 EP 2441 DI 10.1063/1.121377 PG 3 WC Physics, Applied SC Physics GA ZM442 UT WOS:000073540600029 ER PT J AU Kopanski, JJ Mayo, S AF Kopanski, JJ Mayo, S TI Intermittent-contact scanning capacitance microscope for lithographic overlay measurement SO APPLIED PHYSICS LETTERS LA English DT Article AB A scanning-capacitance-microscope (SCM) mode was implemented by using an atomic force microscope (AFM) operated in intermittent contact and by measuring the tip-to-sample capacitance change at the tip vibration frequency. The intermittent-contact-mode SCM was able to image and determine the overlay separation of metal lines buried under a 1-mu m-thick, planarized dielectric layer. Modeling of the intermittent-contact SCM signal across buried metal lines was consistent with the experimental results. This hybrid intermittent-contact AFM and SCM has the potential to measure the lithographic overlay between metal lines located at consecutive levels beneath dielectric layers in an integrated circuit. [S0003-6951(98)04119-9]. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. EM joseph.kopanski@nist.gov NR 12 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 11 PY 1998 VL 72 IS 19 BP 2469 EP 2471 DI 10.1063/1.121397 PG 3 WC Physics, Applied SC Physics GA ZM442 UT WOS:000073540600039 ER PT J AU Straty, GC Muzny, CD Butler, BD Lin, MY Slawecki, TM Glinka, CJ Hanley, HJM AF Straty, GC Muzny, CD Butler, BD Lin, MY Slawecki, TM Glinka, CJ Hanley, HJM TI In situ rheometric shearing apparatus at the NIST Center for Neutron Research SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE rheometer; small angle neutron scattering (SANS); micelle; viscosity; Couette geometry ID RODLIKE MICELLES; SCATTERING; FLOW; POLYMER; ORDER; SUSPENSIONS; DISPERSIONS; TRANSITIONS; ALIGNMENT; GRADIENT AB A constant stress Couette cell rheometer has been modified to measure simultaneously the viscometric properties and neutron scattering intensities from the NIST Center for Neutron Research (NCNR) small angle neutron scattering (SANS) spectrometers. The apparatus was constructed to complement scattering radiation experiments of solutions under shear. The apparatus is capable of high accuracy measurements with viscosities that can range over about ten orders of magnitude. Sample plots showing simultaneous measurements of the viscosity and the anisotropic scattering patterns from micellar solutions are presented. The apparatus is easily adapted for light scattering. (C) 1998 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Muzny, CD (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. EM muzny@boulder.nist.gov NR 31 TC 10 Z9 11 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 1998 VL 408 IS 2-3 BP 511 EP 517 DI 10.1016/S0168-9002(98)00206-X PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA ZY162 UT WOS:000074592500015 ER PT J AU Jentschura, U Soff, G Ivanov V Karshenboim, SG AF Jentschura, U Soff, G Ivanov, V Karshenboim, SG TI Wave function correction to the decay of pionium and heavy fermionium SO PHYSICS LETTERS A LA English DT Article DE exotic atoms; radiative corrections; pionium; heavy fermionium; mesoatoms ID PI(-) MESONS; ATOMS; LIFETIME; PI(+) AB The decay rates of heavy atomic systems consisting of a particle and its own antiparticle are influenced by the probability density ("charge density", square of the wave function) at the origin. In heavy systems, the one-loop electronic vacuum polarization induces a correction to the charge density (at the origin) of relative order alpha/pi. The correction is analyzed in this Letter, and results are provided for dimuonium (mu(+)mu(-) atom), pionium (pi(+)pi(-) atom), and the hypothetical heavy tauonium (tau(+)tau(-) atom). We investigate the correction in the limit of strong binding and discuss the applicability of the effective charge approach to derive leading logarithmic asymptotics. (C) 1998 Published by Elsevier Science B.V. C1 Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Pulkovo Observ, St Petersburg 196140, Russia. Max Planck Inst Phys Komplexer Syst, D-01069 Dresden, Germany. DI Mendeleev Inst Metrol, St Petersburg 198005, Russia. RP Jentschura, U (reprint author), Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany. EM ulrich@theory.phy.tu-dresden.de; sgk@onti.vniim.sbp.su RI Ivanov, Vladimir/B-9957-2011; Karshenboim, Savely/C-1456-2011 NR 19 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD MAY 11 PY 1998 VL 241 IS 6 BP 351 EP 356 DI 10.1016/S0375-9601(98)00147-9 PG 6 WC Physics, Multidisciplinary SC Physics GA ZN314 UT WOS:000073633500007 ER PT J AU McMillin, LM Goldberg, MD Ding, HJ Susskind, J Barnet, CD AF McMillin, LM Goldberg, MD Ding, HJ Susskind, J Barnet, CD TI Forward calculation for interferometers: method and validation SO APPLIED OPTICS LA English DT Article ID ACCURATE TRANSMITTANCE MODEL; ATMOSPHERIC TRANSMITTANCE; ABSORBING GAS; COMPUTATIONALLY FAST; MIXING RATIOS; OPTRAN AB An approach to approximating the instrument response for an unapodized interferometer is presented. The approach comprises functions that are local enough in frequency space (no more than five wave numbers) that one can use the Planck function at a single frequency to calculate the radiance at a given frequency and atmospheric pressure level, and it is well behaved (transmittances change monotonically from 1.0 to 0.0), so existing transmittance calculation procedures can be used. It is faster than calculating radiances at a high resolution, doing a Fourier transform, and then doing a second transform, and it produces brightness temperatures that agree with exact values to better than the 0.01 K that is due to errors in the approximation. The approach is accurate enough and fast enough to be used for calculating unapodized radiances from an interferometer. It also can be used to calculate transmittances as well as radiances. (C) 1998 Optical Society of America. C1 Natl Environm Satellite Data & Informat Serv, Satellite Res Lab, Off Res & Applicat, Washington, DC 20233 USA. QSS Grp Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Gen Sci Corp, Greenbelt, MD 20771 USA. RP McMillin, LM (reprint author), Natl Environm Satellite Data & Informat Serv, Satellite Res Lab, Off Res & Applicat, Washington, DC 20233 USA. RI Barnet, Christopher/F-5573-2010; Goldberg, Mitch/F-5589-2010 NR 10 TC 3 Z9 3 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 10 PY 1998 VL 37 IS 14 BP 3059 EP 3068 DI 10.1364/AO.37.003059 PG 10 WC Optics SC Optics GA ZL890 UT WOS:000073483800028 PM 18273253 ER PT J AU Baker, ET Massoth, GJ Feely, RA Cannon, GA Thomson, RE AF Baker, ET Massoth, GJ Feely, RA Cannon, GA Thomson, RE TI The rise and fall of the CoAxial hydrothermal site, 1993-1996 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DE-FUCA RIDGE; EAST PACIFIC RISE; APPARENT MAGMATIC BUDGET; FLOW-INJECTION-ANALYSIS; VOLCANIC-ERUPTION; SPECTROPHOTOMETRIC DETECTION; DIKE INJECTION; MIDOCEAN RIDGE; CLEFT SEGMENT; VENT FLUIDS AB In June 1993, a seafloor dike intrusion along the CoAxial segment of the Juan de Fuca Ridge was acoustically detected. A near-immediate field response and repeated plume mapping and sampling surveys during eight cruises over the next 3 years have provided a unique opportunity to estimate heat and mass fluxes from both event and chronic discharge during the life cycle of a newly created hydrothermal system. The intrusion triggered the release of at least three event plumes followed by chronic discharge focused at two sites: Flow, the site of a lava eruption at the distal end of the intrusion; and Floc, 30 km back along the trend of the dike. We have combined measurements of plume temperature anomalies, plume areal extent, and year-long averages of current how at both sites to estimate the chronic hydrothermal heat flux H-u. Initial values of H-u at both sites were of order 10(4) MW, declining over time t as H-u = at(-k), with k approximate to 1. Significant plumes were no longer detectable at Flow by June 1995, or at Floc by June 1996. Elemental fluxes from the CoAxid system have been derived from H-u and measurements of the ratios Mn/heat, Fe/heat, and particulate S/heat in chronic plumes. While Mn and Fe fluxes mirrored the power curve decline of heat, the combined regional particulate S (PS) flux experienced a second pronounced maximum some months after the eruption owing to a sharp increase in the S/heat ratio at Floc. Integrated inventories from chronic discharge were similar to 4 x 10(17) J for heat, similar to 3 x 10(8) mol for Mn, similar to 2 x 10(8) mol for Fe, and similar to 1 x 10(8) mol for PS. Realistic uncertainties for all species are roughly a factor of 2. The three event plumes accounted for <5% of the chronic plume inventories. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Fisheries & Oceans Canada, Inst Ocean Sci, Sidney, BC V8L 4B2, Canada. RP Baker, ET (reprint author), NOAA, Pacific Marine Environm Lab, Bldg 3,7600 Sand Point Way NE, Seattle, WA 98115 USA. EM baker@pmel.noaa.gov; massoth@pmel.noaa.gov; feely@pmel.noaa.gov; cannon@pmel.noaa.gov; rick@ios.bc.ca RI Wright, Dawn/A-4518-2011 OI Wright, Dawn/0000-0002-2997-7611 NR 47 TC 29 Z9 29 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 10 PY 1998 VL 103 IS B5 BP 9791 EP 9806 DI 10.1029/97JB03112 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZM406 UT WOS:000073536500015 ER PT J AU Chadwick, WW Embley, RW AF Chadwick, WW Embley, RW TI Graben formation associated with recent dike intrusions and volcanic eruptions on the mid-ocean ridge SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DE-FUCA-RIDGE; EAST PACIFIC RISE; KRAFLA FISSURE SWARM; RECENT LAVA FLOWS; SUBMERSIBLE OBSERVATIONS; HYDROTHERMAL ACTIVITY; SURFACE DEFORMATION; COAXIAL SEGMENT; MIDOCEAN RIDGE; RIFT ZONES AB Grabens have been mapped immediately adjacent to recently erupted submarine lava flows on the Cleft and CoAxial segments of the Juan de Fuca Ridge (JdFR). The grabens are 10-100 m wide and 5-15 m deep and are located uprift and/or downrift of the eruptive vents that fed the flows. We interpret that these structures formed (or were reactivated) directly over the dike that fed the eruptions as it was intruding toward the surface. These graben structures are primary conduits for diffuse hydrothermal venting on the seafloor during the cooling of newly intruded dikes. The axial summit "graben" or "caldera" on the East Pacific Rise (EPR) in some locations has similar dimensions to the grabens observed on the JdFR, and we interpret that it too may be a dike-induced graben structure (although often buried by subsequent eruptions where it is narrowest). These grabens on the JdFR and the EPR are distinctly narrower and deeper than grabens that formed during well-documented dike intrusions on slow spreading rifts on land (Iceland and Afar). Mechanical modeling suggests that narrow grabens would form when a dike is at shallow depth where it imposes a high stress perturbation on the ambient stress state to cause faulting. Therefore the narrow grabens on the JdFR and EPR imply that a relatively high level;of horizontal compressive stress typically exists perpendicular to the ridges, and this must be overcome by high dike-induced perturbations to cause faulting. This is probably because gradual plate spreading rarely gets enough time to lower the compressive stress significantly due to the high frequency of dike intrusion events relative to the plate spreading rate. The dikes that do intrude in this environment must have relatively high internal magma pressure. Therefore the size and character of dike-induced grabens that form at the surface on intermediate to fast spreading ridges reflect the fact that volcanism dominates over tectonism in regulating the local stress state where a robust magma supply is available. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. NOAA, Hatfield Marine Sci Ctr, Pacific Marine Environm Lab, Newport, OR USA. RP Chadwick, WW (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, 2115 SE OSU Dr, Newport, OR 97365 USA. EM chadwick@pmel.noaa.gov NR 87 TC 54 Z9 54 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 10 PY 1998 VL 103 IS B5 BP 9807 EP 9825 DI 10.1029/97JB02485 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZM406 UT WOS:000073536500016 ER PT J AU Jones, CH Phinney, RA AF Jones, CH Phinney, RA TI Seismic structure of the lithosphere from teleseismic converted arrivals observed at small arrays in the southern Sierra Nevada and vicinity, California SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID WESTERN UNITED-STATES; SEVIER-LARAMIDE OROGENY; TIME-DOMAIN DECONVOLUTION; SHALLOW-ANGLE SUBDUCTION; ISOTOPIC EVIDENCE; BODY WAVES; RECEIVER FUNCTIONS; CRUSTAL STRUCTURE; RANGE PROVINCE; NORESS ARRAY AB 21 well-distributed teleseisms (30 degrees to 100 degrees distance) were recorded by mixed broad-band (BB) and short-period (SP) seismic arrays at Mineral King (MK) and Horseshoe Meadow (HM) in the southern Sierra Nevada and at Darwin Plateau (DP) between the Inyo and Argus ranges. These arrays permit identification and separation of direct P and S arrivals, reflections from topography, scattered energy, and arrivals from different back azimuths (multipath arrivals). P-to-S conversions can be identified from beamed BE or SP seismograms. Least squares time domain processing recovered single-event receiver functions from these beamed seismograms. Converted phases attributable to the Moho are clear and uncomplicated at DP; Ps-P times of 3.9-4.2 s correspond to crustal thicknesses of 31-33 km, assuming a mean P crustal velocity of 6.2 km/s and a Poisson's ratio (v) of 0.255. Ps-P times at HM (eastern Sierra) are 3.9-4.6 s (32-37 km) excepting some unusual seismograms from events at back azimuths of 225 degrees-239 degrees. MK (western Sierra) times for Ps-P show a strong E-W asymmetry: 3.9-4.1 s (31-33 km) from the east, and 4.8-5.3 s (39-42 km) from the west. The MK arrivals from the east are multiple and substantially weaker by comparison with HM and DP. These results confirm the absence of a thick crust under the southern High Sierra inferred from both a refraction experiment coincident with this experiment and some earlier studies. At DP the Moho event follows an intracrustal negative polarity event defining the top of an S wave low-velocity zone. This feature dips west under the Sierran crest at HM but is absent farther west at MK. This feature appears to be a manifestation of extensional strain and thus indicates that the surficially undeformed Sierra overlies a tectonized lower crust. Sub-Moho energy is absent under the Basin and Range (DP) but is conspicuous under the High Sierra at positive arrivals similar to 7.3 s (MK) and similar to 9 s (HM) after the P. These arrivals might be from the base of a low-velocity, low-density upper mantle body supporting the Sierra. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. RP Jones, CH (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Campus Box 216, Boulder, CO 80309 USA. EM cjones@mantle.colorado.edu; bob@geo.princeton.edu OI Jones, Craig/0000-0002-1698-0408 NR 82 TC 95 Z9 99 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAY 10 PY 1998 VL 103 IS B5 BP 10065 EP 10090 DI 10.1029/97JB03540 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA ZM406 UT WOS:000073536500033 ER PT J AU Rodriguez-Romero, A Almog, O Tordova, M Randhawa, Z Gilliland, GL AF Rodriguez-Romero, A Almog, O Tordova, M Randhawa, Z Gilliland, GL TI Primary and tertiary structures of the Fab fragment of a monoclonal anti-E-selectin 7A9 antibody that inhibits neutrophil attachment to endothelial cells SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID RHINOVIRUS NEUTRALIZING ANTIBODY; CRYSTAL-STRUCTURE; ADHESION MOLECULE-1; BINDING-SITE; CRYSTALLIZATION; RECOGNITION; REFINEMENT; COMPLEX; GROWTH AB The murine monoclonal IgG1 antibody 7A9 binds specifically to the endothelial leukocyte adhesion molecule-1 (E-selectin), inhibiting the attachment of neutrophils to endothelial cells. The primary and three-dimensional structures of the Fab fragment of 7A9 are reported. The amino acid sequence was determined by automated Edman degradation analysis of proteolytic fragments of both the heavy and light chains of the Fab, The sequences of the two chains are consistent with that of the IgG1 class with an associated kappa light chain with two intrachain disulfide bridges in each of the heavy and light chains. The tertiary structure of the antibody fragment was determined by x-ray crystallographic methods at 2.8 Angstrom resolution. The F(ab')(2) molecule, treated with dithiothreitol, crystallizes in the space group P2(1)2(1)2(1) with unit cell parameters a = 44.5 Angstrom, b = 83.8 Angstrom, and c 132.5 Angstrom with one Fab molecule in the asymmetric unit. The structure was solved by the molecular replacement method and subsequently refined using simulated annealing followed by conventional least squares optimization of the coordinates. The resulting model has reasonable stereochemistry with an R factor of 0.195, The 7A9 Fab structure has an elbow bend of 162 degrees and is remarkably similar to that of the monoclonal anti-intercellular adhesion molecule-1 (ICAM-1) antibody Fab fragment. The 7A9 antigen combining site presents a groove resembling the structure of the anti-ICAM-1 antibody, and other antibodies raised against surface receptors and peptides, Residues from the six complementary determining regions (CDRs) and framework residues form the floor and walls of the groove that is approximately 22 Angstrom wide and 8 Angstrom deep and that is lined with many aromatic residues. The groove is large enough to accommodate the loop between beta-strands beta(4) and beta(5), of the lectin domain of E-selectin that has been implicated in neutrophil adhesion (1). C1 Natl Inst Stand & Technol, Rockville, MD 20850 USA. Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Autonomous Univ Mexico, Inst Quim, Mexico City 04510, DF, Mexico. Otsuka Amer Pharmaceut Inc, Rockville, MD 20850 USA. RP Rodriguez-Romero, A (reprint author), Natl Inst Stand & Technol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI RODRIGUEZ-ROMERO, ADELA/C-7723-2015 NR 38 TC 9 Z9 9 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAY 8 PY 1998 VL 273 IS 19 BP 11770 EP 11775 DI 10.1074/jbc.273.19.11770 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZM408 UT WOS:000073536700054 PM 9565600 ER PT J AU Chen, X Tordova, M Gilliland, GL Wang, LC Li, Y Yan, HG Ji, XH AF Chen, X Tordova, M Gilliland, GL Wang, LC Li, Y Yan, HG Ji, XH TI Crystal structure of apo-cellular retinoic acid-binding protein type II (R111M) suggests a mechanism of ligand entry SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE cellular retinoic acid-binding protein type II; retinoic acid; crystal structure; ligand entry; intracellular lipid-binding proteins ID FATTY-ACID; ESCHERICHIA-COLI; SECONDARY STRUCTURE; REFINEMENT; RAT; APOPROTEIN; RECEPTOR; CRYSTALLOGRAPHY; PURIFICATION; EXPRESSION AB The crystal structure of unliganded mutant R111M of human cellular retinoic acid-binding protein type II (apo-CRABPII (R111M)) has been determined at 2.3 Angstrom and refined fro a crystallographic R-factor of 0.18. Although the mutant protein has lower affinity for all-trans-retinoic acid (RA) than the wild-type, it is properly folded, and its conformation is very similar to the wild-type. apo-CRABPII (R111M) crystallizes in space group P1 with two molecules in the unit cell. The two molecules have high structural similarity except that their alpha 2 helices differ strikingly. Analyses of the molecular conformation and crystal packing environment suggest that one of the two molecules assumes a conformation compatible with RA entry. Three structural elements encompassing the opening of the binding pocket exhibit large conformational changes, when compared with holo-CRABPII, which include the alpha 2 helix and the beta C-beta D and beta E-beta F hairpin loops. The alpha 2 helix is unwound at its N terminus, which appears to be essential for the opening of the RA-binding pocket. Three arginine side-chains (29, 59, and 132) are found with their guanidino groups pointing into the RA-binding pocket. A three-step mechanism of TCA entry has been proposed, addressing the opening of the RA entrance, the electrostatic potential that directs entry of RA into the binding pocket, and the intramolecular interactions that stabilize the RA.CRABPII complex via locking the three flexible structural elements when RA is bound. (C) 1998 Academic Press Limited. C1 NCI, Frederick Canc Res & Dev Ctr, ABL Basic Res Program, Frederick, MD 21702 USA. Univ Maryland, Ctr Adv Res Biotechnol, Inst Biotechnol, Rockville, MD 20850 USA. NIST, Rockville, MD 20850 USA. Michigan State Univ, Dept Biochem, E Lansing, MI 48824 USA. RP Ji, XH (reprint author), NCI, Frederick Canc Res & Dev Ctr, ABL Basic Res Program, POB B, Frederick, MD 21702 USA. RI Ji, Xinhua/C-9664-2012 OI Ji, Xinhua/0000-0001-6942-1514 NR 58 TC 26 Z9 27 U1 0 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD MAY 8 PY 1998 VL 278 IS 3 BP 641 EP 653 DI 10.1006/jmbi.1998.1734 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZP641 UT WOS:000073773800013 PM 9600845 ER PT J AU Longfellow, CA Imamura, T Ravishankara, AR Hanson, DR AF Longfellow, CA Imamura, T Ravishankara, AR Hanson, DR TI HONO solubility and heterogeneous reactivity on sulfuric acid surfaces SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID STRATOSPHERIC TEMPERATURES; CHEMICAL-REACTION; AQUEOUS SURFACES; HCL; KINETICS; WATER; ACTIVATION; CHEMISTRY; INTERFACE; AEROSOLS AB The solubility of HONO in various wt % sulfuric acid solutions was measured. HONO becomes increasingly more soluble in high acid wt % Solutions, probably resulting from the protonation of HONO to give H2ONO+, followed by dissociation and association to give NO+HSO4-(nitrosyl sulfuric acid). The reaction of HONO with HCl on 50, 60, 67, and 70 wt % sulfuric acid solutions was also studied. The measured uptake coefficients could not be explained simply by the occurrence of a bulk phase reaction, and a surface effect is found to contribute to the uptake. The reaction of HONO with HCl was measured on sulfuric acid particles, and a small reacto-diffusive length further supports a surface reaction. From extrapolating our measured uptake values to stratospheric conditions, the formation of ClNO from the heterogeneous reaction of HONO and HCl is concluded to be an insignificant process in the volcanically unperturbed stratosphere. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Hanson, DR (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Ravishankara, Akkihebbal/A-2914-2011 NR 46 TC 40 Z9 41 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 7 PY 1998 VL 102 IS 19 BP 3323 EP 3332 DI 10.1021/jp9807120 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZP699 UT WOS:000073779600015 ER PT J AU Edler, KJ Reynolds, PA Brown, AS Slawecki, TM White, JW AF Edler, KJ Reynolds, PA Brown, AS Slawecki, TM White, JW TI Shear and salt effects on the structure of MCM-41 synthesis gels SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID ANGLE NEUTRON-SCATTERING; MOLECULAR-SIEVE MCM-41; MICELLES AB Orientational ordering under shear was observed for some precursor gels for the synthesis of the hexagonal mesoporous silica MCM-41 in the presence of high KBr concentrations. The presence of KBr disrupted the formation of the first-order MCM-41 diffraction peak dependent upon KBr concentration. Synthesis gels which formed good quality MCM-41, but with no added KBr salt, were not oriented by strong shearing. In addition MCM-41 formed without shear and salt was not disrupted by subsequent shearing. C1 Australian Natl Univ, Res Sch Chem, Canberra, ACT 0200, Australia. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP White, JW (reprint author), Australian Natl Univ, Res Sch Chem, Canberra, ACT 0200, Australia. RI Edler, Karen/A-7324-2011 OI Edler, Karen/0000-0001-5822-0127 NR 20 TC 9 Z9 9 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD MAY 7 PY 1998 VL 94 IS 9 BP 1287 EP 1291 DI 10.1039/a707394a PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA ZM824 UT WOS:000073580000019 ER PT J AU Parsons, JF Xiao, GY Gilliland, GL Armstrong, RN AF Parsons, JF Xiao, GY Gilliland, GL Armstrong, RN TI Enzymes harboring unnatural amino acids: Mechanistic and structural analysis of the enhanced catalytic activity of a glutathione transferase containing 5-fluorotryptophan SO BIOCHEMISTRY LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; D-LACTATE DEHYDROGENASE; S-TRANSFERASE; ESCHERICHIA-COLI; 3-DIMENSIONAL STRUCTURE; SITE; BINDING; TYROSINE-6; PROTEINS; PRODUCT AB The catalytic characteristics and structure of the M1-1 isoenzyme of rat glutathione (GSH) transferase in which all four tryptophan residues in each monomer are replaced with 5-fluorotryptophan are described. The fluorine-for-hydrogen substitution does not change the interaction of the enzyme with GSH even though two tryptophan residues (Trp7 and Trp45) are involved in direct hydrogen-bonding interactions with the substrate. The rate constants for association and dissociation of the peptide, measured by stopped-flow spectrometry, remain unchanged by the unnatural amino acid. The 5-FTrp-substituted enzyme exhibits a k(cat) of 73 s(-1) as compared to 18 s(-1) for the native enzyme toward 1-chloro-2,4-dinitrobenzene. That the increase in the turnover number is due to an enhanced rate of product release in the mutant is confirmed by the kinetics of the approach to equilibrium for binding of the product, The crystal structure of the 5-FTrp-containing enzyme was solved at a resolution of 2.0 Angstrom by difference Fourier techniques. The structure reveals local conformational changes in the structural elements that define the approach to the active site which are attributed to steric interactions of the fluorine atoms associated with 5-FTrp146 and 5-FTrp214 in domain II. These changes appear to result in the enhanced rate of product release. This structure represents the first of a protein substituted with 5-fluorotryptophan. C1 Vanderbilt Univ, Sch Med, Dept Biochem, Nashville, TN 37232 USA. Vanderbilt Univ, Sch Med, Dept Chem, Nashville, TN 37232 USA. Vanderbilt Univ, Sch Med, Ctr Mol Toxicol, Nashville, TN 37232 USA. Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. NIST, Rockville, MD 20850 USA. RP Armstrong, RN (reprint author), Vanderbilt Univ, Sch Med, Dept Biochem, 221 Kirkland Hall, Nashville, TN 37232 USA. FU NIEHS NIH HHS [P30 ES00267]; NIGMS NIH HHS [GM30910] NR 34 TC 38 Z9 38 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 5 PY 1998 VL 37 IS 18 BP 6286 EP 6294 DI 10.1021/bi980219e PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ZM880 UT WOS:000073585600009 PM 9572843 ER PT J AU Markelz, AG Heilweil, EJ AF Markelz, AG Heilweil, EJ TI Temperature-dependent terahertz output from semi-insulating GaAs photoconductive switches SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSMISSION SPECTROSCOPY; SEMICONDUCTOR SURFACES; GENERATION; DOMAIN; PULSES AB The temperature dependence of the terahertz (THz) output power and spectra from biased photoconductive switches was measured for several antenna gap widths and applied biases. The spectrally integrated THz output had a nonmonotonic temperature dependence in all cases with the value increasing by a factor of 3 from room temperature to 150 K for low biases and 100 K at high biases. An abrupt decrease in output power occurs below 90 K, and the spectrum shifts to lower frequencies as the temperature is lowered. (C) 1998 American Institute of Physics. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Markelz, AG (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. OI Markelz, Andrea/0000-0003-0443-4319 NR 21 TC 20 Z9 20 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 4 PY 1998 VL 72 IS 18 BP 2229 EP 2231 DI 10.1063/1.121329 PG 3 WC Physics, Applied SC Physics GA ZK775 UT WOS:000073362300011 ER PT J AU Semancik, S Cavicchi, R AF Semancik, S Cavicchi, R TI Kinetically controlled chemical sensing using micromachined structures SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID GAS SENSORS; SNO2 FILMS; SURFACE C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Semancik, S (reprint author), NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 20 TC 98 Z9 100 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD MAY PY 1998 VL 31 IS 5 BP 279 EP 287 DI 10.1021/ar970071b PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ZP666 UT WOS:000073776300011 ER PT J AU Vasquez, GB Ji, XH Fronticelli, C Gilliland, GL AF Vasquez, GB Ji, XH Fronticelli, C Gilliland, GL TI Human carboxyhemoglobin at 2.2 angstrom resolution: Structure and solvent comparisons of R-state, R2-state and T-state hemoglobins SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID X-RAY-DIFFRACTION; HUMAN DEOXYHEMOGLOBIN; CRYSTAL-STRUCTURE; CARBON-MONOXIDE; REFINEMENT; BINDING; STEREOCHEMISTRY; BOND AB The three-dimensional structure and associated solvent of human carboxyhemoglobin at 2.2 Angstrom resolution are compared with other R-state and T-state human hemoglobin structures. The crystal form is isomorphous with that of the 2.7 Angstrom structure of carboxyhemoglobin reported earlier [Baldwin (1980). J. Mel. Biol. 136, 103-128], whose coordinates were used as a starting model, and with the 2.2 Angstrom structure described in an earlier report [Derewenda ct al. (1990). J.; Mel. Biol. 211, 515-519]. During the course of the refinement, a natural mutation of the alpha-subunit, A53S, was discovered that forms a new crystal contact through a bridging water molecule. The protein structure shows a significant difference between the alpha and beta heme geometries, with Fe-C-O angles of 125 and 162 degrees, respectively. The carboxyhemoglobin is compared with other fully ligated R-state human hemoglobins [Baldwin (1980). J. Mel. Biol. 136, 103-128; Shaanan (1983). J. Mel. Biol. 195, 419-422] with the R2-state hemoglobin [Silva et al. (1992). J. Biol. Chem. 267, 17248-17256] and with T-state deoxyhemoglobin [Fronticelli et al. (1994). J. Biol. Chem. 269, 23965-23969]. The structure is similar to the earlier reported R-state structures, but there are differences in many side-chain conformations, the associated water structure and the presence and the position of a phosphate ion. The quaternary changes between the R-state carboxyhemoglobin and the R2-state and T-state structures are in general consistent with those reported in the earlier structures. The location of 238 water molecules and a phosphate ion in the carboxyhemoglobin structure allows the first comparison of the solvent structures of the R-state and T-state structures. Distinctive hydration patterns for each of the quaternary structures are observed, but a number of conserved water molecule binding sites are found that are independent of the conformational state of the protein. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. NIST, Rockville, MD 20850 USA. Univ Maryland, Sch Med, Dept Biochem & Mol Biol, Baltimore, MD 21201 USA. RP Vasquez, GB (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RI Ji, Xinhua/C-9664-2012 OI Ji, Xinhua/0000-0001-6942-1514 FU NHLBI NIH HHS [P01 HL48517] NR 45 TC 30 Z9 30 U1 0 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD MAY 1 PY 1998 VL 54 BP 355 EP 366 DI 10.1107/S0907444997012250 PN 3 PG 12 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA ZQ149 UT WOS:000073827200008 PM 9761903 ER PT J AU Gallagher, DT Eisenstein, E Fisher, KE Zondlo, J Chinchilla, D Yu, HD Dill, J Winborne, E Ducote, K Xiao, GY Gilliland, GL AF Gallagher, DT Eisenstein, E Fisher, KE Zondlo, J Chinchilla, D Yu, HD Dill, J Winborne, E Ducote, K Xiao, GY Gilliland, GL TI Polymorphous crystallization and diffraction of threonine deaminase from Escherichia coli SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID STRUCTURAL BASIS; PROTEINS; RESOLUTION AB The biosynthetic threonine deaminase from Escherichia coli, an allosteric tetramer with key regulatory functions, has been crystallized in several crystal forms. Two distinct forms, both belonging to either space group P3(1)21 or P3(2)21, with different sized asymmetric units that both contain a tetramer, grow under identical conditions. Diffraction data sets to 2.8 Angstrom resolution (native) and 2.9 Angstrom resolution (isomorphous uranyl derivative) have been collected from a third crystal form in space group I222. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. RP Gallagher, DT (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. EM travis@dtg.nist.gov NR 18 TC 2 Z9 2 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD MAY 1 PY 1998 VL 54 BP 467 EP 469 DI 10.1107/S0907444997011360 PN 3 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA ZQ149 UT WOS:000073827200035 PM 9761930 ER PT J AU Mackey, EA Becker, DA AF Mackey, EA Becker, DA TI Determination of methylmercury in two mussel tissue Standard Reference Materials by pre-irradiation separation and neutron activation analysis SO ANALYST LA English DT Article; Proceedings Paper CT 3rd International Symposium on Speciation of Trace Elements in Biological, Environmental and Toxicological Sciences CY SEP 15-19, 1997 CL PORT DOUGLAS, AUSTRALIA SP Univ New S Wales, Natl Inst Occupat Hlth, McMaster Univ, Inst Environ & Hlth, MAFF, CSL, Food Sci Lab DE Conway dish acid distillation; methylmercury; mussel tissue; neutron activation analysis; Standard Reference Material ID GAS-CHROMATOGRAPHY; MERCURY; EXTRACTION; SEDIMENTS; STABILITY; SAMPLES AB A method was developed for the measurement of organically bound mercury in two mussel tissue Standard Reference Materials (SRM): SRM 2974 Organics in Mussel Tissue and SRM 2976 Mussel Tissue. Organomercury compounds were distilled from a mixture of powdered sample (approximately 200 mg), sulfuric acid and copper(II) sulfate, and bound chemically to cysteine fixed on to tilter-paper. The filter papers were subjected to neutron activation analysis (NAA) for mercury determination. Other analytical methods were used to confirm that most (greater than or equal to 99 %) of the organically bound mercury is present in the form of methylmercury for these two mussel reference materials. With this established, the results from the determination of organomercury compounds for this work are reported as the amount of mercury in the form of methylmercury. The average and standard deviation of the results of analyses of four aliquots of Reference Material IAEA-350 Tuna were 3.61 +/- 0.20 mu g g(-1) [with a 95% confidence interval (95% Ct) of +/-0.69 mu g g(-1)], compared with a certified value of 3.65 mu g g(-1) and 95% Ct of 3.32-4.01 mu g g(-1). The concentration average and standard deviation from analyses of seven aliquots of SRM 2976 Mussel Tissue were 27.9 +/- 3.9 ng g(-1) (95% CI, +/- 5.2 ng g(-1)); results from analyses of five aliquots of SRM 2974 yielded 78.3 +/- 9.6 ng g(-1) (95% CI, +/- 15.0 ng g(-1)), Results obtained using this method compared well with results obtained by other investigators using three different analytical methods, and were used in the certification df methylmercury concentrations in these two SRMs. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Mackey, EA (reprint author), NIST, Div Analyt Chem, Bldg 235,B117, Gaithersburg, MD 20899 USA. NR 27 TC 4 Z9 5 U1 0 U2 0 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0003-2654 J9 ANALYST JI Analyst PD MAY PY 1998 VL 123 IS 5 BP 779 EP 783 DI 10.1039/a707453k PG 5 WC Chemistry, Analytical SC Chemistry GA ZN568 UT WOS:000073658900004 ER PT J AU Fischer, DA Mitchell, GE Yeh, AT Gland, JL AF Fischer, DA Mitchell, GE Yeh, AT Gland, JL TI Functional group orientation in surface and bulk polystyrene studied by ultra soft X-ray absorption spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article DE polystyrene; X-ray absorption fine structure ID FILM SURFACES; EXCITATION-SPECTRA; DEPENDENCE; POLYIMIDE; POLYMERS AB The composition and orientation of functional groups at the surface and within the bulk of thin polystyrene films were studied by ultra soft X-ray absorption spectroscopy above the carbon K edge. The polystyrene films, which were produced by spin casting from solvents, were of varying thicknesses (1.5 to 100 nm) and molecular weights (3.8 kDa to 1000 kDa). Electron-yield and fluorescence-yield ultra soft X-ray absorption spectroscopy were used to probe simultaneously the surface (less than or equal to 3.6 nm) and the bulk (similar to 300 nm) of the polystyrene films. For the films studied, the pendant phenyl groups were found to be preferentially oriented toward the surface normal, independent of casting solvent, molecular weight, and film thickness. Additionally, the preferential orientation of the phenyl rings was slightly enhanced in the bulk versus the surface. The preferred orientation of the phenyl groups implies an orientation of the polymer backbone that is preferentially parallel to the surface of the films. The results indicate that the intramolecular forces may be more important than the intermolecular forces in determining polymer conformations at the surface and in bulk polystyrene. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Dow Chem Co, Analyt Sci Div, Midland, MI 48667 USA. Univ Michigan, Dept Chem, Ann Arbor, MI 48109 USA. RP Fischer, DA (reprint author), Brookhaven Natl Lab, NIST PRT, Bldg 510E, Upton, NY 11973 USA. NR 21 TC 31 Z9 31 U1 4 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 133 IS 1-2 BP 58 EP 64 DI 10.1016/S0169-4332(98)00007-5 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZX205 UT WOS:000074489900008 ER PT J AU Schenck, PK Vaudin, MD Bonnell, DW Hastie, JW Paul, AJ AF Schenck, PK Vaudin, MD Bonnell, DW Hastie, JW Paul, AJ TI Particulate reduction in the pulsed laser deposition of barium titanate thin films SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Laser Ablation (COLA 97) CY JUL 21-25, 1997 CL MONTEREY BAY, CA DE particulate reduction; pulsed laser deposition; barium titanate thin films ID ABLATION; YBA2CU3O7-X; GROWTH; METALS AB A particulate-reduction approach has been developed, based on a pulsed supersonic gas-jet that selectively deflects particulates from the deposition stream during pulsed laser deposition of BaTiO3 thin films. In situ imaging, using an intensified CCD camera, has shown that the desirable atomic, ionic, and molecular species move toward the substrate with velocities on the order of 10(6) cm s(-1), while the undesirable particulates move at velocities on the order of 10(4) cm s(-1) and slower. This separation of velocities is sufficient that the pulsed gas-jet can be timed to impact the particulates after the vapor species reach the substrate, but while the particulates are still near the target, allowing for near-maximum deflection. Key parameters with this approach are the sharpness and the timing of the valve opening and closing. Initial results show that at least an order of magnitude reduction in the number of film particulates is achieved. (C) 1998 Elsevier Science B.V. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM pkschenck@nist.gov; markvaudin@nist.gov; bonnell@nist.gov; jwhastie@nist.gov; ajpaul@nist.gov NR 32 TC 13 Z9 14 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 EI 1873-5584 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 1998 VL 127 BP 655 EP 661 DI 10.1016/S0169-4332(97)00721-6 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA ZP584 UT WOS:000073768100110 ER PT J AU Crescenti, GH AF Crescenti, GH TI The degradation of Doppler sodar performance due to noise: A review SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE sodar; noise; acoustic scattering; wind measurement; urban monitoring ID PLANETARY BOUNDARY-LAYER; ACOUSTIC SOUNDER; RADAR AB Ambient background noise is a common problem for poor Doppler sodar performance. This noise can be active or passive and broad-band or narrow-band. Active broad-band noise decreases the sounding range of the sodar by decreasing the signal-to-noise ratio. Active narrow-band noise can be interpreted as erroneous wind values. Passive noise sources are objects which reflect the transmitted acoustic pulse back to the sodar with zero Doppler shift. Use of acoustic shielding is discussed as a method of noise pollution control by isolating the side lobe energy of the transmitted acoustic pulse. At the same time, these acoustic shields are effective in blocking out active ambient background noise. Previous studies which experienced noise interference are shown as examples of problems that are frequently encountered. Published by Elsevier Science Ltd. C1 NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27709 USA. RP Crescenti, GH (reprint author), NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27709 USA. NR 60 TC 11 Z9 12 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAY PY 1998 VL 32 IS 9 BP 1499 EP 1509 DI 10.1016/S1352-2310(97)00385-3 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZP049 UT WOS:000073711400004 ER PT J AU Mathur, R Young, JO Schere, KL Gipson, GL AF Mathur, R Young, JO Schere, KL Gipson, GL TI A comparison of numerical techniques for solution of atmospheric kinetic equations SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE atmospheric chemistry; stiff ODEs; numerical integration; air quality modeling; photochemical mechanism ID ACID DEPOSITION MODEL; CHEMICAL-KINETICS; CHEMISTRY; MECHANISM; SOLVERS; INTEGRATION; GENERATION; SCHEMES; URBAN AB Numerical modeling of atmospheric chemistry is a computationally intensive problem. The equations describing the interaction among various modeled chemical species are coupled, nonlinear ordinary differential equations. Spatial dependencies in comprehensive three-dimensional air quality models require the solution of this system at thousands of spatial points. Even with increasing computer power, there is a need for efficient and accurate numerical solvers with expanded capabilities, since the next generation of air quality simulation models needs to address the increasingly complex chemistry issues emerging in new model applications. Variants of the commonly used quasi steady-state approximation and the hybrid methods currently used in several modeling systems are examined against a reference mechanism describing chemical interactions related to tropospheric oxidant and acid formation. Additional modifications to the methods are incorporated to yield more robust integration techniques. The chemistry solution methodology used in the regional acid deposition model is also incorporated in this comparison as a base methodology for representing the reference chemical mechanism. The methods are tested against the Gear integration scheme for a variety of test cases including traditional box-model calculations and detailed three-dimensional simulations, and their relative accuracies and efficiencies are investigated. Performance and implementation issues related to chemical integration schemes are examined in the context of the demands and needs of the chemistry component of future comprehensive atmospheric chemistry/transport simulation models. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 MCNC, Environm Programs, Res Triangle Pk, NC 27709 USA. NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. RP Mathur, R (reprint author), MCNC, Environm Programs, POB 12889, Res Triangle Pk, NC 27709 USA. NR 28 TC 13 Z9 15 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAY PY 1998 VL 32 IS 9 BP 1535 EP 1553 DI 10.1016/S1352-2310(97)00381-6 PG 19 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZP049 UT WOS:000073711400007 ER PT J AU Leathers, DJ Kluck, DR Kroczynski, S AF Leathers, DJ Kluck, DR Kroczynski, S TI The severe flooding event of January 1996 across north-central Pennsylvania SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The rapid ablation of a snowpack and intense rainfall combined to cause catastrophic flooding across much of the mid-Atlantic region of the United States on 18 and 19 January 1996. This flooding event resulted in as many as 30 fatalities, numerous injuries, and damage estimated at $1.5 billion. The Loyalsock and Lycoming Creek watersheds in northern Pennsylvania were arguably the hardest hit areas in the region, at least from the perspective of fatalities and injuries. This flooding event, which was certainly devastating from a human and economic perspective, also represents an interesting scientific situation in which climatological preconditioning and the occurrence of an unusual synoptic-scale weather event combined to create disastrous results. Before the event, snow fell at record levels across northern Pennsylvania during the late autumn and early winter seasons. By the middle of January 1996, more snow had fallen across the combined watershed region than is expected during an average snowfall season. The heavy snowfall, in conjunction with anomalously low temperatures, combined to create an exceptionally deep snowpack containing 7.5-15 cm of snow water equivalent. A strong synoptic-scale disturbance that moved across the United States from 17 through 20 January 1996 initiated meteorological conditions that rapidly ablated the snowpack and dropped more than 7.5 cm of Liquid precipitation in a 24-h period in the combined watershed region. A one-dimensional mass and energy balance snowpack model (SNTHERM) was used to evaluate the magnitude of the surface energy fluxes that were associated with the movement of the synoptic-scale system through the area. Further, the model was used in a sensitivity analysis mode to determine the meteorological variables most important to the ablation of the snowpack. Results indicate that high dewpoint temperatures and high wind speeds were at least as important as high temperatures and precipitation to the severity of the flooding. It was shown that a thorough understanding of the hazardous potential of an event of this type can best be achieved when assessments from diverse disciplines within the natural sciences are employed. C1 Univ Delaware, Dept Geog, Ctr Climat Res, Newark, DE 19716 USA. Natl Weather Serv, Hydrometeorol Design Studies Ctr, Silver Spring, MD USA. RP Leathers, DJ (reprint author), Univ Delaware, Dept Geog, Ctr Climat Res, Newark, DE 19716 USA. RI Leathers, Daniel/A-3665-2010 NR 9 TC 27 Z9 28 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1998 VL 79 IS 5 BP 785 EP 797 DI 10.1175/1520-0477(1998)079<0785:TSFEOJ>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP984 UT WOS:000073809200004 ER PT J AU Klimowski, BA Becker, R Betterton, EA Bruintjes, R Clark, TL Hall, WD Orr, BW Kropfli, RA Piironen, P Reinking, RF Sundie, D Uttal, T AF Klimowski, BA Becker, R Betterton, EA Bruintjes, R Clark, TL Hall, WD Orr, BW Kropfli, RA Piironen, P Reinking, RF Sundie, D Uttal, T TI The 1995 Arizona Program: Toward a better understanding of winter storm precipitation development in mountainous terrain SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID RADAR; CLOUDS AB The 1995 Arizona Program was a field experiment aimed at advancing the understanding of winter storm development in a mountainous region of central Arizona. From 15 January through 15 March 1995, a wide variety of instrumentation was operated in and around the Verde Valley southwest of Flagstaff, Arizona. These instruments included two Doppler dual-polarization radars, an instrumented airplane, a lidar, microwave and infrared radiometers, an acoustic sounder, and other surface-based facilities. Twenty-nine scientists from eight institutions took part in the program. Of special interest was the interaction of topographically induced, storm-embedded gravity waves with ambient upslope flow. It is hypothesized that these waves serve to augment the upslope-forced precipitation that falls on the mountain ridges. A major thrust of the program was to compare the observations of these winter storms to those predicted with the Clark-NCAR 3D, nonhydrostatic numerical model. C1 Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. Natl Weather Serv, Rapid City, SD USA. Navajo Nat, Ft Defiance, AZ USA. NCAR, Boulder, CO USA. NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. Arizona Dept Water Resources, Phoenix, AZ USA. Univ Wisconsin, Madison, WI USA. RP Betterton, EA (reprint author), Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. EM BETTERTON@AIR.ATMO.ARIZONA.EDU NR 33 TC 8 Z9 8 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1998 VL 79 IS 5 BP 799 EP 813 DI 10.1175/1520-0477(1998)079<0799:TAPTAB>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP984 UT WOS:000073809200005 ER PT J AU Rothfusz, LP McLaughlin, MR Rinard, SK AF Rothfusz, LP McLaughlin, MR Rinard, SK TI An overview of NWS weather support for the XXVI olympiad SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The 1996 Centennial Olympic Games in Atlanta, Georgia, received weather support from the National Weather Service (NWS). The mandate to provide this support gave the NWS an unprecedented opportunity to employ in an operational setting several tools and practices similar to those planned for the "modemized" era of the NWS. The project also provided a glimpse of technology and practices not planned for the NWS modernization, but that might be valuable in the future. The underlying purpose of the project was to protect the Life and property of the two million spectators, athletes, volunteers, and officials visiting and/or participating in the games. While there is no way to accurately account for lives and property that were protected by the NWS support, the absence of weather-related deaths, significant injuries, and damaged property during the games despite an almost daily occurrence of thunderstorms, high temperatures, and/or rain indicates that the project was a success. In fact, popular perception held that weather had no effect on the games. The 2000+ weather bulletins issued during the 6-week support period suggest otherwise. The authors describe the many facets of this demanding and successful project, with special attention given to aspects related to operational forecasting. A postproject survey completed by the Olympics forecasters, feedback provided by weather support customers, and experiences of the management team provide the bases for project observations and recommendations for future operational forecasting activities. C1 Natl Weather Serv Forecast Off, Tulsa, OK 74128 USA. NWS So Reg Headquarters, Ft Worth, TX USA. NWS Off, Lake Charles, LA USA. RP Rothfusz, LP (reprint author), Natl Weather Serv Forecast Off, 10159 E 11th St,Suite 300, Tulsa, OK 74128 USA. EM lans.rothfusz@noaa.gov NR 20 TC 13 Z9 16 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1998 VL 79 IS 5 BP 845 EP 860 DI 10.1175/1520-0477(1998)079<0845:AOONWS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP984 UT WOS:000073809200008 ER PT J AU Gaffen, DJ Franklin, DB Friday, EW Gorre-Dale, E Kootval, H Weston, KE AF Gaffen, DJ Franklin, DB Friday, EW Gorre-Dale, E Kootval, H Weston, KE TI The international participation of women in World Meteorological Organization activities and in the fields of meteorology and hydrology SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter C1 NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. NOAA, Natl Weather Serv, Silver Spring, MD 20910 USA. NOAA, Off Ocean & Atmospher Res, Silver Spring, MD 20910 USA. WMO, Informat & Publ Affairs, Geneva, Switzerland. WMO, Publ Weather & Operat Informat Serv, Geneva, Switzerland. RP Gaffen, DJ (reprint author), NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. NR 3 TC 1 Z9 1 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1998 VL 79 IS 5 BP 861 EP 864 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP984 UT WOS:000073809200009 ER PT J AU Bell, GD Halpert, MS AF Bell, GD Halpert, MS TI Climate assessment for 1997 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SOUTHERN OSCILLATION; TEMPERATURE; VARIABILITY; HEMISPHERE; WIND AB The global climate during 1997 was affected by both extremes of the El Nino-Southern Oscillation (ENSO), with weak Pacific cold episode conditions prevailing during January and February, and one of the strongest Pacific warm episodes (El Nino) in the historical record prevailing during the remainder of the year. This warm episode contributed to major regional rainfall and temperature anomalies over large portions of the Tropics and extratropics, which were generally consistent with those observed during past warm episodes. In many regions, these anomalies were opposite to those observed during 1996 and early 1997 in association with Pacific cold episode conditions. Some of the most dramatic El Nino impacts during 1997 were observed in the Tropics, where anomalous convection was evident across the entire Pacific and throughout most major monsoon regions of the world. Tropical regions most affected by excessive El Nino-related rainfall during the year included 1) the eastern half of the tropical Pacific, where extremely heavy rainfall and strong convective activity covered the region from April through December; 2) equatorial eastern Africa, where excessive rainfall during October-December led to widespread flooding and massive property damage; 3) Chile, where a highly amplified and extended South Pacific jet stream brought increased storminess and above-normal rainfall during the winter and spring; 4) southeastern South America, where these same storms produced above-normal rainfall during June-December; and 5) Ecuador and northern Peru, which began receiving excessive rainfall totals in November and December as deep tropical convection spread eastward across the extreme eastern Pacific. In contrast, El Nino-related rainfall deficits during 1997 included 1) Indonesia, where significantly below-normal rainfall from June through December resulted in extreme drought and contributed to uncontrolled wildfires; 2) New Guinea, where drought contributed to large-scale food shortages leading to an outbreak of malnutrition; 3) the Amazon Basin, which received below-normal rainfall during June-December in association with substantially reduced tropical convection throughout the region; 4) the tropical Atlantic, which experienced drier than normal conditions during July-December; and 5) central America and the Caribbean Sea, which experienced below-normal rainfall during March-December. The El Nino also contributed to a decrease in tropical storm and hurricane activity over the North Atlantic during August-November, and to an expanded area of conditions favorable for tropical cyclone and hurricane formation over the eastern North Pacific. These conditions are in marked contrast to both the 1995 and 1996 hurricane seasons, in which significantly above-normal tropical cyclone activity was observed over the North Atlantic and suppressed activity prevailed across the eastern North Pacific. Other regional aspects of the short-term climate during 1997 included 1) wetter than average 1996/97 rainy seasons in both northeastern Australia and southern Africa in association with a continuation of weak cold episode conditions into early 1997; 2) below-normal rainfall and drought in southeastern Australia from October 1996 to December 1997 following very wet conditions in this region during most of 1996; 3) widespread flooding in the Red River Valley of the north-central United States during April following an abnormally cold and snowy winter; 4) floods in central Europe during July following several consecutive months of above-normal rainfall; 5) near-record to record rainfall in southeastern Asia during June-August in association with an abnormally weak upper-level monsoon ridge; and 6) near-normal rainfall across India during the Indian monsoon season (June-September) despite the weakened monsoon ridge. C1 NOAA, NCEP, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Halpert, MS (reprint author), NOAA, NCEP, Climate Predict Ctr, W-NP52,NSC,Rm 605,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 35 TC 45 Z9 48 U1 2 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1998 VL 79 IS 5 BP S1 EP S50 PG 50 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP984 UT WOS:000073809200015 ER PT J AU Friedland, KD Reddin, DG Shimizu, N Haas, RE Youngson, AF AF Friedland, KD Reddin, DG Shimizu, N Haas, RE Youngson, AF TI Strontium : calcium ratios in Atlantic salmon (Salmo salar) otoliths and observations on growth and maturation SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID POST-SMOLT GROWTH; FISH OTOLITHS; ELEMENTAL COMPOSITION; PROTON MICROPROBE; GIRELLA-ELEVATA; CALCIUM RATIOS; AGE; MICROCHEMISTRY; TEMPERATURE; PATTERNS AB In this paper, we report on two data sets that have relevance to contemporary ideas on maturation in Atlantic salmon (Salmo salar): (i) an analysis of maturity fate of Atlantic salmon captured in the southern Labrador Sea and (ii) a study of otolith strontium:calcium ratios for maturing and immature Atlantic salmon. A discrimination function based on gonadosomatic indices was developed to classify maturation state of Atlantic salmon caught in Newfoundland and Labrador fisheries during the period 1985-1988. Atlantic salmon believed to be on feeding migrations were found to be in advanced states of sexual development. In an attempt to clarify the meaning of these data, chronological transects of Sr:Ca ratios from the otoliths of maturing and immature one-seawinter fish were collected. Sr:Ca ratios deposited during freshwater residency varied by stock and appeared to reflect the environmental availability of Sr. Sr:Ca ratios deposited during marine residency appeared to reflect somatic growth and sexual development. We detected no differences in the postsmolt Sr:Ca ratios for mature and immature Atlantic salmon from a hatchery stock originating in North America, suggesting that for this stock, little differentiation occurs between the maturity components. Mechanisms by which environment may contribute to the variation in maturation rate of North American Atlantic salmon are discussed. C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. Fisheries & Oceans Canada, Sci Branch, St Johns, NF A1C 5X1, Canada. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Dept Agr & Fisheries Scotland, Marine Lab, SOAEFD, Aberdeen AB9 8DB, Scotland. RP Friedland, KD (reprint author), Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. RI Facility, NENIMF/B-8811-2015 NR 39 TC 40 Z9 42 U1 1 U2 7 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAY PY 1998 VL 55 IS 5 BP 1158 EP 1168 DI 10.1139/cjfas-55-5-1158 PG 11 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 117NB UT WOS:000075787000012 ER PT J AU Nonacs, P Smith, PE Mangel, M AF Nonacs, P Smith, PE Mangel, M TI Modeling foraging in the northern anchovy (Engraulis mordax): individual behavior can predict school dynamics and population biology SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID COD GADUS-MORHUA; CALIFORNIA CURRENT; FISH; PREDATION; GROWTH; SHOAL; RISK; ZOOPLANKTON; PREY AB Many economically important oceanic fishes travel in large schools, but the foraging behaviors of these schools and the life history consequences of these behaviors have rarely been addressed. The availability of extensive information on bioenergetics of the northern anchovy (Engraulis mordax) allows us to use this species as a case study. We modeled two types of potential behavior that fish could use to exploit a patchy environment: (i) maximizing growth rate or (ii) maximizing survivorship to adulthood and reproduction, which is a function of both growth and avoiding predation. Patterns from existing data sets on gut contents and growth rates from the field for juvenile E. mordax were consistent only with the prediction of maximizing survivorship. The model makes further testable predictions about (i) expected swimming velocities between zooplankton patches, (ii) patterns of size segregation in the formation of schools, (iii) the proportion of zooplankton patches that schools consume, and (iv) reactions to decreases in environmental quality. Overall, the model predicts that anchovies spend at least 25% of their time in schools that are too large to be energetically economical and suggests further research on several variables that could affect populations of schooling fishes. C1 Univ Calif Los Angeles, Dept Biol, Los Angeles, CA 90095 USA. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla Lab, NOAA, La Jolla, CA 92038 USA. Univ Calif Santa Cruz, Dept Environm Studies, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Inst Marine Sci, Santa Cruz, CA 95064 USA. RP Nonacs, P (reprint author), Univ Calif Los Angeles, Dept Biol, 621 Circle Dr S, Los Angeles, CA 90095 USA. RI Nonacs, Peter/A-3159-2008 NR 34 TC 14 Z9 15 U1 0 U2 7 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAY PY 1998 VL 55 IS 5 BP 1179 EP 1188 DI 10.1139/cjfas-55-5-1179 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 117NB UT WOS:000075787000014 ER PT J AU Boltnev, AI York, AE Antonelis, GA AF Boltnev, AI York, AE Antonelis, GA TI Northern fur seal young: interrelationships among birth size, growth, and survival SO CANADIAN JOURNAL OF ZOOLOGY LA English DT Article ID DIFFERENTIAL MATERNAL INVESTMENT; ARCTOCEPHALUS-GAZELLA PUPS; HALICHOERUS-GRYPUS; GREY SEAL; CALLORHINUS-URSINUS; PARENTAL INVESTMENT; MIROUNGA-LEONINA; ELEPHANT SEALS; SEX-RATIO; ISLAND AB We investigated size at birth, growth, and early survival of northern fur seals (Callorhinus ursinus) from birth to weaning at Bering Island, Russia, over 8 breeding seasons from 1982 to 1989. One thousand and thirteen fur seals (565 males and 448 females) were measured in a longitudinal study and an additional 2697 animals were measured at birth. At birth, female pups were about 10% lighter and about 3% shorter than male pups. The coefficients of variation of mass (12.5 and 12.8%) and length (4.5 and 4.7%) were similar for the two sexes. We partitioned the lactation period into four time periods: 1, the perinatal period (ages 0-10 days); 2, the early development period (ages 11-40 days); 3, the period of intensive molting (ages 41-80 days); and 4, the preweaning period (ages 81-140 days). We investigated four measures of growth: absolute growth in mass (AGM) in grams per day, absolute growth in length (AGL) in millimetres per day, relative growth in mass (RGM) as a percentage per day, and relative growth in length (RGL) as a percentage per day. For both sexes, AGM was highest during period 4 (mean = 124.8 g/day, SE = 7.4 g/day, and mean = 109.6 g/day, SE = 6.8 g/day for males and females, respectively) and AGL was highest during period 2 (mean = 3.74 mm/day, SE = 0.18 mm/day, and mean = 3.42 mm/day, SE = 0.21 mm/day for males and females, respectively). RGM (mean = 1.06%, SE = 0.09%, and mean = 1.02%, SE = 0.11% for males and females, respectively) and RGL (mean = 0.53%, SE = 0.03%, and mean = 0.50%, SE = 0.03% for males and females, respectively) were highest during period 2 for both sexes. For both sexes, growth rates were slowest during the molting period. Sexual differences were detected in AGM in period 4 and for the combined data over periods 1-3. Sexual differences in AGL were detected for the combined data over periods 1 3, and 4 only. No sexual differences in relative growth were found. Subsequent growth in mass and length was correlated with birth size. We found the greatest annual variation during the periods when growth was fastest. Condition indices were calculated using the allometric relationship between length and mass separately for neonates and pups older than 5 days. The condition indices at birth varied significantly annually. The condition index was lowest during the molting period (3). Animals that survived for at least 40 days were larger at birth and had a higher condition index than those that did not survive. In years of moderate or high pup survival rates, survival rates were higher in animals born later in the breeding season. C1 Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, Seattle, WA 98115 USA. Kamchatka Res Inst Fisheries & Oceanog, Kamchatka 683602, Russia. RP Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM york@orca.akctr.noaa.gov NR 86 TC 53 Z9 53 U1 1 U2 13 PU CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS PI OTTAWA PA 65 AURIGA DR, SUITE 203, OTTAWA, ON K2E 7W6, CANADA SN 0008-4301 EI 1480-3283 J9 CAN J ZOOL JI Can. J. Zool. PD MAY PY 1998 VL 76 IS 5 BP 843 EP 854 DI 10.1139/cjz-76-5-843 PG 12 WC Zoology SC Zoology GA 127GU UT WOS:000076343200008 ER PT J CA Natl Inst Stand Technol Natl Qual Program TI Use the Baldrige criteria to improve your business SO CHEMTECH LA English DT Article C1 Natl Inst Stand & Technol, Natl Qual Program, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Natl Qual Program, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2703 J9 CHEMTECH JI Chemtech PD MAY PY 1998 VL 28 IS 5 BP 6 EP 11 PG 6 WC Chemistry, Applied SC Chemistry GA ZL987 UT WOS:000073493500006 ER PT J AU Solow, AR Adams, RF Bryant, KJ Legler, DM O'Brien, JJ McCarl, BA Nayda, W Weiher, R AF Solow, AR Adams, RF Bryant, KJ Legler, DM O'Brien, JJ McCarl, BA Nayda, W Weiher, R TI The value of improved enso prediction to US agriculture SO CLIMATIC CHANGE LA English DT Article ID EPIC MODEL AB The economic value of long-range weather prediction is measured by the increase in social welfare arising from the use of the prediction in economic decisionmaking. This paper describes a study of the economic value of ENSO prediction to U.S. agriculture. The interdisciplinary study involved the analysis of data and models from meteorology, plant science, and economics under a framework based on Bayesian decision analysis. The estimated annual Value of perfect ENSO prediction to U.S. agriculture is $323 million. C1 Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Oregon State Univ, Dept Agr & Resource Econ, Corvallis, OR 97331 USA. Univ Arkansas, SE Res Ctr, Monticello, AR 71656 USA. Florida State Univ, Ctr Ocean Atmosphere Predict Studies, Tallahassee, FL 32306 USA. Texas A&M Univ, Dept Agr Econ, College Stn, TX 77843 USA. NOAA, Off Policy & Strateg Planning, Washington, DC 20230 USA. RP Solow, AR (reprint author), Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. RI McCarl, Bruce/E-9445-2011 NR 15 TC 71 Z9 73 U1 2 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1998 VL 39 IS 1 BP 47 EP 60 DI 10.1023/A:1005342500057 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA ZR366 UT WOS:000073967400004 ER PT J AU Baum, RT McGrattan, KB Nyden, MR AF Baum, RT McGrattan, KB Nyden, MR TI An examination of the applicability of computed tomography for the measurement of component concentrations in fire-generated plumes SO COMBUSTION AND FLAME LA English DT Article ID SMOLDERING COMBUSTION; RECONSTRUCTION; DRIVEN; FLOWS; WOOD AB The purpose of this investigation is to examine the feasibility df using computed tomography to evaluate the predictive capabilities of fire models. In this pursuit, we have analyzed data fi om both laboratory-and computer-generated plumes in order to determine the number of line-of-sight measurements, the detector topology, and the temporal resolution needed to obtain accurate reconstructions of component concentrations in fire atmospheres. (C) 1998 by The Combustion Institute. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Nyden, MR (reprint author), NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 37 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1998 VL 113 IS 3 BP 358 EP 372 DI 10.1016/S0010-2180(97)00219-8 PG 15 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA ZF805 UT WOS:000072935000006 ER PT J AU Zelkowitz, MV Wallace, DR AF Zelkowitz, MV Wallace, DR TI Experimental models for validating technology SO COMPUTER LA English DT Article AB Experimentation helps determine the effectiveness of proposed theories and methods. But computer science has not developed a concise taxonomy of methods that could be used to demonstrate the validity of new software development techniques. Partly as a result of this, the state of experimentation in software engineering is poor. In this article, the authors describe the: four general approaches to experimentation and the important aspects of data collection. They propose a taxonomy for software engineering experimentation that describes 12 different experimental approaches. To underscore the need for experimentation, the authors also analyze 612 papers in software engineering published in 1985, 1990, and 1995. They classified each paper according to the data collection method used to validate the claims in the paper. They found that about a third of the papers had no experimental validation, and many authors used sloppy terminology to describe their validation method. The software engineering community, the authors conclude, can do a better job reporting its results. This, in turn, will help industry select the right new technology to implement. C1 Univ Maryland, College Pk, MD 20742 USA. NIST, Software Qual Grp, Washington, DC USA. NIST, Reference Data Software Error Fault Failure Data, Washington, DC USA. RP Zelkowitz, MV (reprint author), Univ Maryland, College Pk, MD 20742 USA. RI Fettke, Peter/E-9691-2010 NR 9 TC 92 Z9 92 U1 1 U2 7 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9162 J9 COMPUTER JI Computer PD MAY PY 1998 VL 31 IS 5 BP 23 EP 31 DI 10.1109/2.675630 PG 9 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA ZL217 UT WOS:000073410500004 ER PT J AU Cooper, JA Chapleau, F AF Cooper, JA Chapleau, F TI Phylogenetic status of Paralichthodes algoensis (Pleuronectiformes : Paralichthodidae) SO COPEIA LA English DT Article C1 Univ Ottawa, Dept Biol, Ottawa, ON K1N 6N5, Canada. Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab MRC 153, Washington, DC 20560 USA. RP Chapleau, F (reprint author), Univ Ottawa, Dept Biol, POB 450 Stn A, Ottawa, ON K1N 6N5, Canada. EM cooper.andrew@nmnh.si.edu NR 14 TC 24 Z9 24 U1 0 U2 0 PU AMER SOC ICHTHYOLOGISTS & HERPETOLOGISTS PI MIAMI PA MAUREEN DONNELLY, SECRETARY FLORIDA INT UNIV BIOLOGICAL SCIENCES, 11200 SW 8TH STREET, MIAMI, FL 33199 USA SN 0045-8511 EI 1938-5110 J9 COPEIA JI Copeia PD MAY 1 PY 1998 IS 2 BP 477 EP 481 DI 10.2307/1447445 PG 5 WC Zoology SC Zoology GA ZN379 UT WOS:000073640000022 ER PT J AU Sadek, F Mohraz, B Lew, HS AF Sadek, F Mohraz, B Lew, HS TI Single- and multiple-tuned liquid column dampers for seismic applications SO EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS LA English DT Article DE earthquake loading; energy dissipation; passive control; tuned liquid column dampers; tuned mass dampers ID MASS AB Design parameters for single-and multiple-tuned liquid column dampers for reducing the response of structures to seismic excitations are presented. A deterministic analysis is carried out using 72 earthquake ground motion records to determine the tuning ratio, tube width to liquid length ratio, and head loss coefficient corresponding to a given mass ratio for single-tuned liquid column dampers. A similar analysis is performed to determine the central tuning ratio, tuning bandwidth, and grouping of dampers for multiple-tuned liquid column dampers. The study indicates that by properly selecting the design parameters, single-and multiple-tuned liquid column dampers can reduce the response of structures to seismic excitation by up to 45 per cent. Design examples using single-and multiple-tuned liquid column dampers in a bridge and a ten-storey building are presented to illustrate how the parameters are selected and to demonstrate the performance of the devices under different ground excitations. The response of several structures with tuned liquid column dampers is compared with that using tuned mass dampers where it is shown that both devices result in comparable reductions in the response, (C) 1998 John Wiley & Sons, Ltd. This paper was produced under the auspices of the U.S. Government and it is therefore not subject to copyright in the U.S. C1 NIST, Bldg & Fires Res Lab, US Dept Commerce, Struct Div, Gaithersburg, MD 20899 USA. So Methodist Univ, Dallas, TX 75275 USA. RP Mohraz, B (reprint author), NIST, Bldg & Fires Res Lab, US Dept Commerce, Struct Div, Bldg 226,Room B-158, Gaithersburg, MD 20899 USA. NR 15 TC 36 Z9 38 U1 3 U2 14 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0098-8847 J9 EARTHQUAKE ENG STRUC JI Earthq. Eng. Struct. Dyn. PD MAY PY 1998 VL 27 IS 5 BP 439 EP 463 DI 10.1002/(SICI)1096-9845(199805)27:5<439::AID-EQE730>3.0.CO;2-8 PG 25 WC Engineering, Civil; Engineering, Geological SC Engineering GA ZJ864 UT WOS:000073261400003 ER PT J AU Rodriguez, H Akman, SA AF Rodriguez, H Akman, SA TI Large scale isolation of genes as DNA fragment lengths by continuous elution electrophoresis through an agarose matrix SO ELECTROPHORESIS LA English DT Article DE electrophoresis; isolation; purification; enrichment; DNA; gene ID LIGATION MEDIATED PCR; RESTRICTION FRAGMENTS; NUCLEOTIDE RESOLUTION; SKIN-CANCER; P53; HOTSPOTS; DAMAGE; REPAIR AB A simple procedure for the isolation of genes as DNA fragment lengths is described. By using a commercial continuous elution protein electrophoresis apparatus and incorporating an agarose matrix, preparative scale amounts (300 mu g) of DNA can be purified by fragment lengths from a mixture of genomic fragment lengths with high recovery yields. Fractions corresponding to unique fragment length ranges are screened for individual genes by dot-blot analysis. Using this technique, we have isolated two genes: PGK1, a single copy housekeeping gene; and p53 (exons 3-11), a tumor suppressor gene, whose DNA fragment lengths elute at 4 and 7.5 kbp, respectively, from a single preparative run. As an example of the utility of the technique, we applied it to improving the sensitivity of the ligation-mediated polymerase chain reaction (LMPCR) - a nucleic acid amplification technique used for the detection and mapping of DNA damage along genes. By eliminating excess nontargeted genomic DNA, the agarose matrix continuous elution electrophoresis (CEE) procedure provided a 24-fold increase id signal strength attributable to base damage caused by exposing DNA to reactive oxygen species. Genomic DNA fragment length purification by agarose matrix CEE should also prove useful in other research areas requiring gene isolation, such as genomics and molecular biology. C1 City Hope Natl Med Ctr, Beckman Res Inst, Dept Biol, Duarte, CA 91010 USA. Wake Forest Univ, Ctr Comprehens Canc, Dept Canc Biol, Winston Salem, NC 27109 USA. RP Rodriguez, H (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Bldg 222,Room A353, Gaithersburg, MD 20899 USA. FU NCI NIH HHS [1PO1 CA69449] NR 20 TC 13 Z9 13 U1 0 U2 3 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD MAY PY 1998 VL 19 IS 5 BP 646 EP 652 DI 10.1002/elps.1150190506 PG 7 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA ZN876 UT WOS:000073692400005 PM 9629891 ER PT J AU Kucklick, JR Baker, JE AF Kucklick, JR Baker, JE TI Organochlorines in Lake Superior's food web SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID POLYCHLORINATED BIPHENYL CONGENERS; STABLE NITROGEN ISOTOPES; GREAT-LAKES; CHAIN STRUCTURE; TOXAPHENE; PCBS; BIOMAGNIFICATION; ECOSYSTEM; SEDIMENT; FISH AB Lake Superior's food web was analyzed in 1994 for hydrophobic organochlorine contaminants (OCs) including toxaphene, chlordane and metabolites, hexachlorocyclohexanes, hexachlorobenzene, dieldrin, and polychlorinated biphenyl congeners. Toxaphene was the dominant organochlorine contaminant in the Lake Superior food web, with concentrations 2-15 times higher than total PCBs. Among the biota studied, wet weight toxaphene levels were highest in bloaters (Coregonus hoyi) at 1100 +/- 270 ng/g (mean +/- 1 standard deviation) and lowest in Mysis relicta (32 +/- 804 ng/g). Total PCB concentrations ranged more than a factor of 20 on a wet weight basis but less than a factor of 6 on a lipid weight basis. The lipid content of the organisms explains 81% of the variability in wet weight t-PCB, with trophic position exerting a smaller influence. Using path analysis and regression techniques, the main influence of trophic position on t-PCBs was shown to be due to the concurrent increase in lipid content with trophic position. The relative distributions of organochlorines among trophic levels were very similar, despite the 3 orders of magnitude range in OC hydrophobicity. Unlike our work in Lake Baikal, the accumulation of OCs in the Lake Superior food web was not significantly (p < 0.05) related to the log octanol/water (K-ow) partition coefficient, suggesting either that organochlorines in this food web equilibrate with surrounding dissolved OCs rapidly relative to dietary uptake or that the OC assimilation efficiency of predators does not vary with log K-ow. Based on OC concentrations in benthic amphipods, we conclude that settling particles are an important source of OCs to deep water organisms in Lake Superior. C1 Univ Maryland, Chesapeake Biol Lab, Solomons, MD 20688 USA. RP Kucklick, JR (reprint author), Natl Inst Stand & Technol, Charleston Lab, 219 Ft Johnson Rd, Charleston, SC 29412 USA. EM john.kucklick@nist.gov RI Baker, Joel/A-9685-2011 OI Baker, Joel/0000-0002-9980-7781 NR 39 TC 76 Z9 81 U1 1 U2 19 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 1998 VL 32 IS 9 BP 1192 EP 1198 DI 10.1021/es970794q PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA ZL156 UT WOS:000073404400023 ER PT J AU Anderson, BS Hunt, JW Phillips, BM Tudor, S Fairey, R Newman, J Puckett, HM Stephenson, M Long, ER Tjeerdema, RS AF Anderson, BS Hunt, JW Phillips, BM Tudor, S Fairey, R Newman, J Puckett, HM Stephenson, M Long, ER Tjeerdema, RS TI Comparison of marine sediment toxicity test protocols for the amphipod Rhepoxynius abronius and the polychaete worm Nereis (Neanthes) arenaceodentata SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Rhepoxynius abronius; Nereis (Neanthes) arenaceodentata; sediment toxicity; minimum significant difference ID ORGANIC-CARBON; BAY; CALIFORNIA AB The 10-d amphipod survival toxicity test protocol using Rhepoxynius abronius was compared to the 20-d polychaete worm growth and survival protocol using Nereis (Neanthes) arenaceodentata. Of the 341 sediment samples collected in California and tested over a 2-year period, 78% significantly inhibited R. abronius survival, whereas 2 and 26% significantly inhibited N. arenaceodentata survival and biomass, respectively. Statistical power associated with each protocol endpoint was determined,by calculating the minimum significant difference (MSD) for each test protocol for this data set. The 90th percentile MSDs for R. abronius survival and N. arenaceodentata survival and biomass were 16, 36, and 56%, respectively. Survival of R. abronius was significantly negatively correlated with a number of toxicants including metals, pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls. No significant correlations were determined between N. arenaceodentata survival or biomass and contaminants measured. Amphipod survival was also negatively correlated with sediment total organic carbon and grain size, but when samples with a high percent fine grain size (>90% fines) were eliminated from consideration, the overall conclusions of the study were not altered. The 10-d amphipod survival protocol using R. abronius was a more sensitive indicator of toxicity, but the results indicate that this was due to greater statistical power rather than greater sensitivity of the test organisms or endpoints. C1 Univ Calif Santa Cruz, Inst Marine Sci, Monterey, CA 93940 USA. Marine Pollut Studies Lab, Monterey, CA 93940 USA. Moss Landing Marine Labs, Dept Fish & Game, Moss Landing, CA 95039 USA. San Jose State Univ Fdn, Moss Landing, CA 95039 USA. NOAA, ORCA, Coastal Monitoring & Bioeffects Assessment Div, Seattle, WA 98115 USA. RP Anderson, BS (reprint author), Univ Calif Santa Cruz, Inst Marine Sci, 34500 Coast Route 1, Monterey, CA 93940 USA. EM bsanders@cats.ucsc.edu NR 34 TC 18 Z9 19 U1 0 U2 8 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAY PY 1998 VL 17 IS 5 BP 859 EP 866 DI 10.1897/1551-5028(1998)017<0859:COMSTT>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZJ235 UT WOS:000073193200013 ER PT J AU Horness, BH Lomax, DP Johnson, LL Myers, MS Pierce, SM Collier, TK AF Horness, BH Lomax, DP Johnson, LL Myers, MS Pierce, SM Collier, TK TI Sediment quality thresholds: Estimates from hockey stick regression of liver lesion prevalence in English sole (Pleuronectes vetulus) SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE hockey stick regression; threshold; environmental assessment; polycyclic aromatic hydrocarbons; fish ID DOSE-RESPONSE MODELS; PUGET-SOUND; PAROPHRYS-VETULUS; RISK ASSESSMENT; CARCINOGENESIS; CHEMICALS; CRITERIA; EPIZOOTIOLOGY AB Comprehensive, integrative assessments of coastal sediment quality are best effected by using large, diverse data sets that include measures of biological dysfunction observed in association with chronic exposure to sediment contaminants. Under the auspices of the National Oceanic and Atmospheric Administration's National Status and Trends Program, the National Benthic Surveillance Project accumulated a database of synoptic sediment contaminant concentrations and indices of biological effects that were measured in indigenous animals collected during field surveys conducted from 1984 to 1994. This compilation of data provided the opportunity to develop a new approach for determining sediment quality criteria to add to the current repertoire of environmental assessment tools. Using a two-segment hockey stick regression, statistically significant chemical thresholds of biological effects were estimated for hepatic lesion prevalences in English sole (Pleuronectes vetulus, formerly Parophrys vetulus) in relation to sediment concentrations of polycyclic aromatic hydrocarbons. These threshold estimates are notably lower than many of those reported for other techniques. Application of this relatively simple dose-response model to subacute, chronic effects that are involved in hepatocarcinogenesis and associated with sediment toxicant content (1) reflects the link between toxicopathic disease progression and conditions observed in benthic fish exposed to contaminants and (2) provides endpoints for assessing sediment quality contaminant concentrations that are not necessarily acutely fatal but may have long-term health implications for populations that are chronically exposed. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Horness, BH (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM beth.horness@noaa.gov NR 52 TC 28 Z9 29 U1 0 U2 4 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAY PY 1998 VL 17 IS 5 BP 872 EP 882 DI 10.1897/1551-5028(1998)017<0872:SQTEFH>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZJ235 UT WOS:000073193200015 ER PT J AU Long, ER MacDonald, DD Cubbage, JC Ingersoll, CG AF Long, ER MacDonald, DD Cubbage, JC Ingersoll, CG TI Predicting the toxicity of sediment-associated trace metals with simultaneously extracted trace metal: Acid-volatile sulfide concentrations and dry weight-normalized concentrations: A critical comparison SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE sediment criteria; sediment quality guidelines; trace metals; sediment toxicity ID ESTUARINE SEDIMENTS; CADMIUM AB The relative abilities of sediment concentrations of simultaneously extracted trace metal: acid-volatile sulfide (SEM: AVS) and dry weight-normalized trace metals to correctly predict both toxicity and nontoxicity were compared by analysis of 77 field-collected samples. Relative to the SEM:AVS concentrations, sediment guidelines based upon dry weight-normalized concentrations were equally or slightly more accurate in predicting both nontoxic and toxic results in laboratory tests. C1 NOAA, ORCA, Coastal Monitoring & Bioeffects Assessment Div, Seattle, WA 98115 USA. MacDonald Environm Sci Ltd, Nanaimo, BC V9X 1C6, Canada. Washington Dept Ecol, Olympia, WA 98504 USA. US Geol Survey, Environm & Contaminants Res Ctr, Columbia, MO 65201 USA. RP Long, ER (reprint author), NOAA, ORCA, Coastal Monitoring & Bioeffects Assessment Div, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM Edward.Long@hazmat.noaa.gov NR 14 TC 39 Z9 45 U1 1 U2 11 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAY PY 1998 VL 17 IS 5 BP 972 EP 974 DI 10.1897/1551-5028(1998)017<0972:PTTOSA>2.3.CO;2 PG 3 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA ZJ235 UT WOS:000073193200029 ER PT J AU Terrados, J Duarte, CM Fortes, MD Borum, J Agawin, NSR Bach, S Thampanya, U Kamp-Nielsen, L Kenworthy, WJ Geertz-Hansen, O Vermaat, J AF Terrados, J Duarte, CM Fortes, MD Borum, J Agawin, NSR Bach, S Thampanya, U Kamp-Nielsen, L Kenworthy, WJ Geertz-Hansen, O Vermaat, J TI Changes in community structure and biomass of seagrass communities along gradients of siltation in SE Asia SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE species richness; community biomass; siltation; seagrasses; SE Asia ID BIODIVERSITY; PRODUCTIVITY; PHILIPPINES; ECOSYSTEMS; MEADOW; PHYTOPLANKTON; ECOLOGY; LOSSES AB The patterns of change in species richness and biomass of Southeast Asian seagrass communities along siltation gradients were compared at different sites in The Philippines and Thailand. Seagrass species richness and community leaf biomass declined sharply when the silt and clay content of the sediment exceeded 15%. Syringodium isoetifolium and Cymodocea rotundata were present only in multispecific meadows, while Enhalus acoroides was the only species remaining in heavily silted sediments. The following ranking of species sensitivity to siltation is proposed (from the least to most sensitive): S. isoetifolium-->C. rotundata-->Thalassia hemprichii-->Cymodocea serulata-->Halodule uninervis-->Halophila ovalis-->Enhalus acoroides. Positive correlations were found between species richness and both community leaf biomass and the leaf biomass of individual seagrass species. The increase in community biomass with increasing species richness was associated with a more even distribution of the leaf biomass among seagrass species. The relationships between percent silt and clay in the sediment and seagrass community leaf biomass and species richness provide useful dose-response relationships which can be used to set allowable or threshold siltation loads in SE Asian coastal waters, and indicate that species loss from seagrass meadows is an early warning of detrimental siltation loads. (C) 1998 Academic Press Limited. C1 CSIC, Ctr Estudios Avanzados Blanes, Blanes 17300, Girona, Spain. Univ Philippines, Inst Marine Sci, Coll Sci, Quezon City 1101, Philippines. Univ Copenhagen, Freshwater Biol Lab, DK-3400 Hillerod, Denmark. Prince Songkla Univ, Coastal Resources Inst, Hat Yai 90112, Thailand. NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, Beaufort Lab, Beaufort, NC 28516 USA. Int Inst Infrastruct Hydraul & Environm Engn, NL-2601 DA Delft, Netherlands. RP Terrados, J (reprint author), CSIC, Ctr Estudios Avanzados Blanes, Cami de Santa Barbara S-N, Blanes 17300, Girona, Spain. RI Terrados, Jorge/B-1062-2008; Vermaat, Jan/I-5856-2012; Duarte, Carlos M/A-7670-2013; Borum, Jens/K-5167-2014; Agawin, Nona Sheila/I-3168-2015 OI Terrados, Jorge/0000-0002-0921-721X; Vermaat, Jan/0000-0003-4250-6790; Duarte, Carlos M/0000-0002-1213-1361; Borum, Jens/0000-0002-4861-6563; Agawin, Nona Sheila/0000-0001-5951-360X NR 40 TC 98 Z9 102 U1 15 U2 40 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD MAY PY 1998 VL 46 IS 5 BP 757 EP 768 DI 10.1006/ecss.1997.0304 PG 12 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA ZQ820 UT WOS:000073906200013 ER PT J AU Bailey, JL Jones, WW Tatem, PA Forney, GP AF Bailey, JL Jones, WW Tatem, PA Forney, GP TI Development of an algorithm to predict vertical heat transfer through ceiling/floor conduction SO FIRE TECHNOLOGY LA English DT Article DE fire model; zone model; heat transfer; model validation AB This paper describes a new algorithm of the Consolidated Fire Growth and Smoke Transport (CFAST) fire model and compares the results with data from real-scale fire tests conducted aboard the ex-USS Shadwell, the U.S. Navy's Research and Development Damage Control Platform. The new phenomenon modeled in this work is the conduction of heat in the vertical direction. The Shadwell tests chosen for validation purposes were part of the Internal Ship Conflagration Control (ISCC) Program. The work focuses on four compartments of the ship that were vertically aligned. The temperatures of the compartments and the decks between them were compared with model predictions. The predictions were very close to the experimental results for ail compartments, although the temperature rise in the topmost compartment was barely above ambient. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bailey, JL (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 12 TC 1 Z9 1 U1 0 U2 2 PU NATIONAL FIRE PROTECTION ASSOC PI QUINCY PA ONE BATTERYMARCH PK, QUINCY, MA 02269 USA SN 0015-2684 J9 FIRE TECHNOL JI Fire Technol. PD MAY-JUN PY 1998 VL 34 IS 2 BP 139 EP 155 DI 10.1023/A:1015377402737 PG 17 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA ZW094 UT WOS:000074373400004 ER PT J AU Nalesnik, CA Hansen, BN Hsu, JT AF Nalesnik, CA Hansen, BN Hsu, JT TI Solubility of pure taxol in supercritical carbon dioxide SO FLUID PHASE EQUILIBRIA LA English DT Article DE Chrastil method; Peng-Robinson equation of state; solid-fluid equilibria; solubility; taxol ID TAXUS-BREVIFOLIA; NITROUS-OXIDE; EXTRACTION AB The solubility of taxol in supercritical carbon dioxide was measured using a high-pressure ultraviolet-visible-light-transmission static cell at pressures from 3000 psia to 7000 psia and temperatures 35 degrees C to 45 degrees C. The solubility of taxol increased by a factor of seven from 0.7 x 10(-7) to 5.0 x 10-7 mole fraction from 3000 psia to 7000 psia. The experimental data were modeled using the Peng-Robinson equation of state and the Chrastil method. The Peng-Robinson equation of state method utilizing k(12) optimum did not provide an adequate fit. The Chrastil method provided a good fit with average absolute relative deviations of 4.6%, 3.6%, and 2.8% for 35 degrees C, 40 degrees C, and 45 degrees C, respectively. (C) 1998 Elsevier Science B.V. All rights reserved. C1 Lehigh Univ, Dept Chem Engn, Bethlehem, PA 18015 USA. Natl Inst Stand & Technol, Div Thermophys, Boulder, CO 80303 USA. RP Hsu, JT (reprint author), Lehigh Univ, Dept Chem Engn, Bethlehem, PA 18015 USA. NR 14 TC 17 Z9 19 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD MAY PY 1998 VL 146 IS 1-2 BP 315 EP 323 DI 10.1016/S0378-3812(98)00220-9 PG 9 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA ZX087 UT WOS:000074478100023 ER PT J AU Phinney, CS Murphy, KE Welch, MJ Ellerbe, PM Long, SE Pratt, KW Schiller, SB Sniegoski, LT Rearick, MS Vetter, TW Vocke, RD AF Phinney, CS Murphy, KE Welch, MJ Ellerbe, PM Long, SE Pratt, KW Schiller, SB Sniegoski, LT Rearick, MS Vetter, TW Vocke, RD TI Definitive method certification of clinical analytes in lyophilized human serum: NIST standard reference material (SRM) 909b SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID DILUTION-MASS-SPECTROMETRY; CHOLESTEROL AB The National Institute of Standards and Technology (NIST) has developed several Standard Reference Materials (SRMs) based on human serum. NIST SRM 909b, Human Serum, is a lyophilized human serum material with concentrations for seven organic and six inorganic analytes at two levels certified solely by definitive methods (DMs). This material provides the vehicle by which high precision, high accuracy measurements made with DMs at NIST can be transferred through the measurement hierarchy to other laboratories. Isotope dilution gas chromatographic-mass spectrometric (GC-IDMS) methods were applied to measure cholesterol, creatinine, glucose, urea, uric acid, triglycerides, and total glycerides. Thermal ionization isotope dilution mass spectrometry (TI-IDMS) was used for determination of lithium, magnesium, potassium, calcium, and chloride. In addition, chloride was determined by coulometry. providing a comparison between two DMs. Sodium, which lacks a stable isotope that would permit isotope dilution mass spectrometric (IDMS) measurement, was determined by gravimetry. SRM 909b includes certified values for total glycerides and triglycerides, which were not certified in the previous lot of this material (SRM 909a). Improvement in uniformity of vial fill weight in the production of SRM 909b resulted in smaller certified uncertainties over previous freeze-dried serum SRMs. Uncertainties at the 99% level of confidence for relative expanded uncertainty (%) for certification of the organic analytes on a mmol/L/g basis ranged from 0.44% for urea (level II) to 5.04% for glucose (level II). (In-house studies have shown glucose to be a relatively unstable analyte in similar lyophilized serum materials, degrading at about 1%, per year.) Relative expanded uncertainties (99% C.I.) for certification of inorganic analytes on a mmol/L/g basis ranged from 0.25% for chloride (level I) to 0.49% for magnesium (level II). C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Phinney, CS (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 30 TC 13 Z9 15 U1 0 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD MAY PY 1998 VL 361 IS 2 BP 71 EP 80 DI 10.1007/s002160050837 PG 10 WC Chemistry, Analytical SC Chemistry GA 104HQ UT WOS:000075009000002 ER PT J AU Heymsfield, AJ Miloshevich, LM Twohy, C Sachse, G Oltmans, S AF Heymsfield, AJ Miloshevich, LM Twohy, C Sachse, G Oltmans, S TI Upper-tropospheric relative humidity observations and implications for cirrus ice nucleation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WAVE CLOUDS; WATER AB Relative humidity (RH) measurements acquired in orographic wave cloud and citrus environments are used to investigate the temperature dependent RH required to nucleate ice crystals in the upper troposphere, RHnuc(T). High ice-supersaturations in clear air - conducive to the maintenance of aircraft contrails yet below RHnuc and therefore insufficient for citrus formation - are not uncommon. Earlier findings are supported that RHnuc in mid-latitude, continental environments decreases from water-saturation at temperatures above -39 degrees C to 75% RH at -55 degrees C. Uncertainty in determining RHnuc below -55 degrees C results in part from size detection limitations of the microphysical instrumentation, but analysis of data from the SUCCESS experiment indicates that RHnuc below -55 degrees C is between 70 and 88%. A small amount of data, acquired off-shore suggests the possibility that RHnuc may also depend on properties of the aerosols. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Heymsfield, AJ (reprint author), Natl Ctr Atmospher Res, Pob 3000, Boulder, CO 80307 USA. EM heyms1@ncar.ucar.edu RI Heymsfield, Andrew/E-7340-2011 NR 7 TC 88 Z9 88 U1 2 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1343 EP 1346 DI 10.1029/98GL01089 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900015 ER PT J AU Chen, YL Kreidenweis, SM McInnes, LM Rogers, DC DeMott, PJ AF Chen, YL Kreidenweis, SM McInnes, LM Rogers, DC DeMott, PJ TI Single particle analyses of ice nucleating aerosols in the upper troposphere and lower stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB A newly developed instrument was deployed on the NASA DC-8 airborne laboratory during the Subsonic Aircraft: Contrail and Cloud Effects Special Study (SUCCESS, Spring 1996) to detect and collect heterogeneous ice nucleating particles (IN) in the upper troposphere and lower stratosphere The elemental compositions of both ambient particles and IN were determined with single particle analysis using analytical electron microscopy. IN collected during flights on May 4 and 8 had enhanced number fractions of metallic, crustal, and carbonaceous particles, compared with the ambient aerosol population, and were relatively deficient in sulfur-containing particles. IN sampled within aircraft exhaust and contrails had higher number fractions of metallic particles, which includes those rich in Zn, Al, and Ti, than the IN sampled in air that was not immediately affected by aircraft exhaust. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Chen, YL (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI DeMott, Paul/C-4389-2011; Kreidenweis, Sonia/E-5993-2011 OI DeMott, Paul/0000-0002-3719-1889; Kreidenweis, Sonia/0000-0002-2561-2914 NR 15 TC 119 Z9 121 U1 1 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1391 EP 1394 DI 10.1029/97GL03261 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900027 ER PT J AU Doney, SC Bullister, JL Wanninkhof, R AF Doney, SC Bullister, JL Wanninkhof, R TI Climatic variability in upper ocean ventilation rates diagnosed using chlorofluorocarbons SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-ATLANTIC OCEAN; CIRCULATION; SECTION; CFC-11; WATER AB The chlorofluorocarbon CFC-12 (CCl2F2) distributions from two occupations of a meridional hydrographic section in the eastern North Atlantic are used to describe the oceanic penetration of CFCs and change in the integrated ventilation patterns over the five years from 1988 to 1993. The CFC-12 water-column inventories increased by 30-40%, despite a slowing atmospheric growth rate (14%), because of continuing uptake by undersaturated subsurface water masses whose response is lagged by the ventilation time-scales. After removing the long-term CFC temporal trend using a tracer age based normalization technique, we observe a distinct dipole pattern in upper ocean ventilation, with reduced convection in the subpolar gyre and enhanced production of saline subtropical underwater in 1993. These differences are discussed in relation to interannual variability in atmospheric surface forcing, upper ocean anomalies, and convection patterns associated with the North Atlantic Oscillation. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Doney, SC (reprint author), Natl Ctr Atmospher Res, Pob 3000, Boulder, CO 80307 USA. EM doney@ncar.ucar.edu; bullister@pmel.noaa.gov; wanninkhof@aoml.noaa.gov RI Doney, Scott/F-9247-2010 OI Doney, Scott/0000-0002-3683-2437 NR 24 TC 25 Z9 25 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1399 EP 1402 DI 10.1029/98GL00844 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900029 ER PT J AU Andronache, C Donner, LJ Ramaswamy, V Seman, CJ Hemler, RS AF Andronache, C Donner, LJ Ramaswamy, V Seman, CJ Hemler, RS TI The effects of atmospheric sulfur on the radiative properties of convective clouds: a limited area modeling study SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DROPLET EFFECTIVE RADIUS; PARAMETERIZATION; ALBEDO AB Convective clouds in tropical areas can be sensitive to the atmospheric sulfate loading, particularly during enhanced sulfate episodes. This assertion is supported by simulations with a high resolution limited area non-hydrostatic model (LAN) employing a detailed sulfate-cloud microphysics scheme, applied to estimate the effects of sulfate on convective clouds in a case study from the Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment (TOGA COARE). Results show that a change in sulfate loading for scenarios using the minimum to the maximum observed values produces a change in the average net flux of shortwave radiation above clouds. This time-average change was estimated between -1.1 and -0.3 Wm(-2) over the integration domain. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Andronache, C (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. RI Andronache, Constantin/C-4431-2011 OI Andronache, Constantin/0000-0001-5375-7056 NR 15 TC 1 Z9 1 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1998 VL 25 IS 9 BP 1423 EP 1426 DI 10.1029/98GL01028 PG 4 WC Geosciences, Multidisciplinary SC Geology GA ZL261 UT WOS:000073414900035 ER PT J AU Wittmann, RC Alpert, BK Francis, MH AF Wittmann, RC Alpert, BK Francis, MH TI Near-field antenna measurements using nonideal measurement locations SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article; Proceedings Paper CT Symposium of the Antenna-Measurement-Techniques-Association CY SEP 30-OCT 06, 1996 CL SEATTLE, WASHINGTON SP Antenna Measurement Techniques Assoc DE antenna measurements ID PROBE-POSITION ERRORS; TRANSFORMATION AB We introduce a near-field to far-field transformation algorithm that relaxes the usual restriction that data points be located on a plane rectangular grid, Computational complexity is O(N log N) where N is the number of data points. This algorithm allows efficient processing of near-field data with known probe position errors. Also, the algorithm is applicable to other measurement approaches such as plane-polar scanning, where data are collected intentionally on a nonrectangular grid. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Wittmann, RC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 25 TC 24 Z9 24 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD MAY PY 1998 VL 46 IS 5 BP 716 EP 722 DI 10.1109/8.668916 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA ZJ759 UT WOS:000073250100017 ER PT J AU Kawalko, SF Kanda, M AF Kawalko, SF Kanda, M TI Numerical and analytical monopole nonplanarity correction factors SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE antenna proximity factors; calibration; monopole antennas AB A numerical procedure for evaluating a nonplanarity correction factor used in monopole calibrations is presented. Results for this numerically computed correction factor are compared with results obtained from an analytical expression for some representative cases. The two approaches are found to be in good agreement for cases of practical interest. C1 Natl Inst Stand & Technol, Div Electromagnet Fields, Boulder, CO 80303 USA. RP Kawalko, SF (reprint author), Natl Inst Stand & Technol, Div Electromagnet Fields, Boulder, CO 80303 USA. NR 4 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD MAY PY 1998 VL 40 IS 2 BP 176 EP 179 DI 10.1109/15.673625 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA ZN242 UT WOS:000073624100015 ER PT J AU Chang, CI Zhao, XL Althouse, MLG Pan, JJ AF Chang, CI Zhao, XL Althouse, MLG Pan, JJ TI Least squares subspace projection approach to mixed pixel classification for hyperspectral images SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE classification; detection; hyperspectral image; oblique subspace projection classifier (OBC); orthogonal subspace projection (OSP); receiver operating characteristics (ROC); signature space orthogonal projection classifier (SSC); target signature space orthogonal projection classifier (TSC) ID ERROR; SPECTROSCOPY AB An orthogonal subspace projection (OSP) method using linear mixture modeling was recently explored in hyperspectral image classification and has shown promise in signature detection, discrimination, and classification. In this paper, the OSP is revisited and extended by three unconstrained least squares subspace protection approaches, called signature space OSP, target signature space OSP, and oblique subspace projection, where the abundances of spectral signatures are not known a priori hut need to be estimated, a situation to which the OSP cannot be directly applied, The proposed three subspace projection methods can be used not only to estimate signature abundance, but also to classify a target signature at subpixel scale so as to achieve subpixel detection. As a result, they can be viewed as a posteriori OSP as opposed to OSP, which can be thought of as a priori OSP, In order to evaluate these three approaches, their associated least squares estimation errors are cast as a signal detection problem in the framework of the Neyman-Pearson detection theory so that the effectiveness of their generated classifiers can be measured by characteristics (ROC) analysis, All results are demonstrated by computer simulations and Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. C1 Univ Maryland Baltimore Cty, Dept Comp Sci & Elect Engn, Remote Sensing Signal & Image Proc Lab, Baltimore, MD 21250 USA. USA, Edgewood Res Dev & Engn Ctr, SCBRD, RTE, Aberdeen Proving Ground, MD 21010 USA. NOAA, Natl Weather Serv, Silver Spring, MD 20910 USA. RP Chang, CI (reprint author), Univ Maryland Baltimore Cty, Dept Comp Sci & Elect Engn, Remote Sensing Signal & Image Proc Lab, Baltimore, MD 21250 USA. EM cchang@umbc2.umbc.edu NR 22 TC 143 Z9 155 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1998 VL 36 IS 3 BP 898 EP 912 DI 10.1109/36.673681 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ZM593 UT WOS:000073555700019 ER PT J AU Milanovic, V Gaitan, M Zaghloul, ME AF Milanovic, V Gaitan, M Zaghloul, ME TI Micromachined thermocouple microwave detector by commercial CMOS fabrication SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article AB This paper reports on the design and testing of a thermocouple microwave detector fabricated through a commercial CMOS foundry with an additional maskless etching procedure. The detector measures true rms power of signals in the frequency range from 50 MHz to 20 GHz, and input power range from -30 to +10 dBm. The device has linearity better than +/-0.4% for input power versus output voltage over the 40-dB dynamic range. Measurements of the return loss, obtained using an automatic network analyzer, show acceptable input return loss of less than -20 dB over the entire frequency range. The sensitivity of the detector was measured to be (1.007 +/- 0.004) mV/mW. C1 George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Milanovic, V (reprint author), George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. NR 10 TC 15 Z9 18 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 1998 VL 46 IS 5 BP 550 EP 553 DI 10.1109/22.668656 PN 1 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA ZL615 UT WOS:000073452200016 ER PT J AU Milanovic, V Ozgur, M DeGroot, DC Jargon, JA Gaitan, M Zaghloul, ME AF Milanovic, V Ozgur, M DeGroot, DC Jargon, JA Gaitan, M Zaghloul, ME TI Characterization of broad-band transmission for coplanar waveguides on CMOS silicon substrates SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE CMOS; coplanar waveguide; deembedding; microwave propagation on silicon substrate; on-wafer measurement ID NETWORK ANALYZER; LINES; CONDUCTOR; PROPAGATION AB This paper presents characteristics of microwave transmission in coplanar waveguides (CPW's) on silicon (Si) substrates fabricated through commercial CMOS foundries, Due to the CMOS fabrication, the metal strips of the CPW are encapsulated in thin films of Si dioxide. Many test sets were fabricated with different line dimensions, all on p-type substrates with resistivities in the range from 0.4 Omega . cm to 12.5 Omega . cm. Propagation constant and characteristic impedance measurements were performed at frequencies from 0.1 to 40 GHz, using a vector-network analyzer and the through-reflect-line (TRL) deembeding technique. A quasi-TEM equivalent circuit model was developed from the available process parameters, which accounts for the effects of the electromagnetic fields in the CPW structure over a broad frequency range. The analysis was based on the conformal mapping of time CPW multilayer dielectric cross section to obtain accurate circuit representation for the effects of the transverse fields. C1 George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. Natl Inst Stand & Technol, Div Electromagnet Fields, Boulder, CO 80303 USA. NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. EM veljko@seas.gwu.edu NR 24 TC 77 Z9 79 U1 2 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9480 EI 1557-9670 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 1998 VL 46 IS 5 BP 632 EP 640 DI 10.1109/22.668675 PN 2 PG 9 WC Engineering, Electrical & Electronic SC Engineering GA ZL616 UT WOS:000073452400008 ER PT J AU Cresswell, MW Allen, RA Guthrie, WF Sniegowski, JJ Ghoshtagore, RN Linholm, LW AF Cresswell, MW Allen, RA Guthrie, WF Sniegowski, JJ Ghoshtagore, RN Linholm, LW TI Electrical linewidth test structures fabricated in monocrystalline films for reference-material applications SO IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING LA English DT Article; Proceedings Paper CT 1997 IEEE International Conference on Microelectronic Test Structures CY MAR 17-20, 1997 CL MONTEREY, CALIFORNIA SP IEEE Electron Devices Soc AB The physical widths of reference features incorporated into electrical linewidth test structures patterned in films of monocrystalline silicon have been determined from Kelvin voltage measurements. The films in which the test structures are patterned are electrically insulated from the bulk-silicon substrate by a layer of silicon dioxide provided by SIMOX (Separation by the IR IMplantation of OXygen) processing. The motivation is to facilitate the development of linewidth reference materials for critical-dimension (CD) metrology-instrument calibration. The selection of the (110) orientation of the starting silicon and the orientation of the structures' features relative to the crystal lattice enable a lattice-plane-selective etch to generate reference-feature proper ties of rectangular cross section and atomically planar sidewalls. These properties are highly desirable for CD applications in which feature widths are certified with nanometer-level uncertainty for use by a diverse range of CD instruments. End applications include the development and calibration of new generations of CD instruments directed at controlling processes for manufacturing devices having sub-quarter-micrometer features. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. Sandia Natl Labs, Microelect Dev Labs, Albuquerque, NM 87185 USA. RP Cresswell, MW (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. EM michael.cresswell@nist.gov NR 15 TC 3 Z9 3 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0894-6507 J9 IEEE T SEMICONDUCT M JI IEEE Trans. Semicond. Manuf. PD MAY PY 1998 VL 11 IS 2 BP 182 EP 193 DI 10.1109/66.670152 PG 12 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZM114 UT WOS:000073506100002 ER PT J AU Larson, K Levine, J AF Larson, K Levine, J TI Time transfer using the phase of the GPS carrier SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID GLOBAL POSITIONING SYSTEM AB We report on tests of time transfer using the phase of the GPS carrier. The first set of experiments used two clocks connected to independent GPS receivers with closely-spaced antennas. The second set of experiments compared a clock at NIST in Boulder with one at the US Naval Observatory in Washington, DC. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Natl Inst Stand & Technol, JILA, Boulder, CO 80303 USA. RP Larson, K (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. NR 3 TC 11 Z9 12 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 1998 VL 45 IS 3 BP 539 EP 540 DI 10.1109/58.677598 PG 2 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA ZQ882 UT WOS:000073912500002 PM 18244205 ER PT J AU Lu, YN Braun, RC Aguirre, A Loh, PC AF Lu, YN Braun, RC Aguirre, A Loh, PC TI Establishment of monk seal cell lines SO IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-ANIMAL LA English DT Letter C1 Univ Hawaii Manoa, Dept Microbiol, Honolulu, HI 96822 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Loh, PC (reprint author), Univ Hawaii Manoa, Dept Microbiol, Snyder Hall 207,2538 Mall, Honolulu, HI 96822 USA. FU NCRR NIH HHS [G12RR/AI-03061] NR 7 TC 5 Z9 6 U1 0 U2 1 PU SOC IN VITRO BIOLOGY PI LARGO PA 9315 LARGO DR WEST, STE 25, LARGO, MD 20774 USA SN 1071-2690 J9 IN VITRO CELL DEV-AN JI In Vitro Cell. Dev. Biol.-Anim. PD MAY PY 1998 VL 34 IS 5 BP 367 EP 369 PG 3 WC Cell Biology; Developmental Biology SC Cell Biology; Developmental Biology GA ZQ625 UT WOS:000073886800005 PM 9639098 ER PT J AU Vasconcellos, ECC Zerbetto, SC Xu, LH Lees, RM Zink, LR Evenson, KM AF Vasconcellos, ECC Zerbetto, SC Xu, LH Lees, RM Zink, LR Evenson, KM TI New far-infrared laser lines and frequency measurements of acetaldehyde and vinyl fluoride SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE far-infrared laser; frequency measurement; acetaldehyde (CH3CHO); vinyl fluoride (CH2CHF); cw CO2 laser; new lines AB Eight far-infrared laser lines have been obtained by optically pumping acetaldehyde (CH3CHO) and nine by pumping vinyl fluoride (CH2CHF) with a cw CO2 laser. The far-infrared laser structure used a metal-dielectric waveguide cavity. This is the first reported observation of four of the laser lines in acetaldehyde. In this work, we measure the frequency, optimum pressure of operation, relative intensity, relative polarization, and pump offset from CO2 laser-line center. C1 UNICAMP, Inst Fis Gleb Wataghin, Dept Elect Quant, BR-13083970 Campinas, SP, Brazil. Univ New Brunswick, Dept Phys Sci, St John, NB E2L 4L5, Canada. Univ New Brunswick, Dept Phys, Fredericton, NB E3B 5A3, Canada. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Vasconcellos, ECC (reprint author), UNICAMP, Inst Fis Gleb Wataghin, Dept Elect Quant, BR-13083970 Campinas, SP, Brazil. RI Xu, Li-Hong/J-5095-2015; Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 8 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD MAY PY 1998 VL 19 IS 5 BP 719 EP 726 DI 10.1023/A:1022646225018 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA ZP318 UT WOS:000073740300001 ER PT J AU Vorburger, TV Dixson, RG Tsai, V Doi, T Song, JF Renegar, TB Fu, J AF Vorburger, TV Dixson, RG Tsai, V Doi, T Song, JF Renegar, TB Fu, J TI Problems in surface metrology SO INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE LA English DT Article; Proceedings Paper CT 7th International Conference on Metrology and Properties of Engineering Surfaces CY APR 02-04, 1997 CL GOTHENBURG, SWEDEN AB Calibrations of surface finish measurements in our laboratory rely on a set of master step-height specimens ranging in size from 29 nm to 152 mu m. These step-height specimens are calibrated in turn by different techniques depending on the step height itself. In order to establish precise values for step heights smaller than 1000 nm, we have established a goal to calibrate several new step-height specimens in this range by three different independent techniques. These are phase shifting interferometric microscopy, a calibrated atomic force microscope (C-AFM), and a high-resolution stylus instrument calibrated by another calibration step. If we can measure precise values of the step height by these different techniques and achieve good agreement, the step-height specimens would then become precise calibration masters. (C) 1998 Published by Elsevier Science Ltd. C1 NIST, Gaithersburg, MD 20899 USA. RP Vorburger, TV (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0890-6955 J9 INT J MACH TOOL MANU JI Int. J. Mach. Tools Manuf. PD MAY-JUN PY 1998 VL 38 IS 5-6 BP 417 EP 418 DI 10.1016/S0890-6955(98)00005-4 PG 2 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA ZM576 UT WOS:000073554000004 ER PT J AU Schwabacher, M Gelsey, A AF Schwabacher, M Gelsey, A TI Multilevel simulation and numerical optimization of complex engineering designs SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA/USAF/NASA/ISSMO 6th Symposium on Multidisciplinary Analysis and Optimization CY SEP 04-06, 1996 CL BELLEVUE, WASHINGTON SP AIAA, USAF, NASA, ISSMO AB Multilevel representations have been studied extensively by artificial intelligence researchers. We present a general method that utilizes the multilevel paradigm to attack the problem of performing multidiscipline engineering design optimization in the presence of many local optima. The method uses a multidisciplinary simulator at multiple levels of abstraction, paired with a multilevel search space. We tested the method in the domain of conceptual design of supersonic transport aircraft, focusing on the airframe and the exhaust nozzle, and using sequential quadratic programming as the optimizer at, each level. We found that using multilevel simulation and optimization can decrease the cost of design space search by an order of magnitude. C1 NIST, Engn Design Technol Grp, Mfg Syst Integrat Div, Gaithersburg, MD 20899 USA. Rutgers State Univ, Dept Comp Sci, Piscataway, NJ 08855 USA. RP Schwabacher, M (reprint author), NIST, Engn Design Technol Grp, Mfg Syst Integrat Div, Gaithersburg, MD 20899 USA. NR 36 TC 0 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1998 VL 35 IS 3 BP 387 EP 397 DI 10.2514/2.2336 PG 11 WC Engineering, Aerospace SC Engineering GA ZQ723 UT WOS:000073896600006 ER PT J AU Hurley, DC Balzar, D Purtscher, PT Hollman, KW AF Hurley, DC Balzar, D Purtscher, PT Hollman, KW TI Nonlinear ultrasonic parameter in quenched martensitic steels SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB We have determined the nonlinear ultrasonic parameter beta and the ultrasonic longitudinal phase velocity nu(L) for a series of martensitic steel specimens which varied in carbon content. The specimens were measured in the as-quenched state to ensure that the carbon was present primarily as an interstitial in the martensite. beta increased monotonically with carbon content and hardness over the range 0.10-0.40 mass % C (39.0-57.5 Rockwell C hardness). However, nu(L) remained virtually the same for all specimens. Therefore we conclude that beta is sensitive to microstructural variations between the specimens, but nu(L) is not. X-ray diffraction experiments indicate that the dislocation density in the specimens is large (similar to 10(11)-10(12)/cm(2)) and increases with increasing carbon content. These results support the hypothesis that the observed increase in beta can be attributed to dislocation-related effects in the specimens. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Hurley, DC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM hurley@boulder.nist.gov NR 30 TC 37 Z9 39 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1998 VL 83 IS 9 BP 4584 EP 4588 DI 10.1063/1.367241 PG 5 WC Physics, Applied SC Physics GA ZM292 UT WOS:000073523900005 ER PT J AU Deshler, T Oltmans, SJ AF Deshler, T Oltmans, SJ TI Vertical profiles of volcanic aerosol and polar stratospheric clouds above Kiruna, Sweden: Winters 1993 and 1995 SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE polar stratospheric clouds; stratospheric aerosol; water vapor profiles; decay of Pinatubo aerosol ID MASS-SPECTROMETER MEASUREMENTS; NITRIC-ACID; ARCTIC STRATOSPHERE; BALLOON OBSERVATIONS; PINATUBO AEROSOL; HNO3 PROFILES; OZONE; WATER; EVOLUTION; GROWTH AB Vertical profiles of aerosol were measured in February 1993, and January - March 1995 using balloon-borne particle counters released from Kiruna, Sweden. Condensation nuclei (CN) and aerosol with radii greater than or equal to 0.15 - 10.0 mu m were measured in 8-12 size classes. The three flights in 1993 were within the polar vortex. Temperatures were below polar stratospheric cloud (PSC) threshold temperatures on one night and a thin PSC was observed. The volcanic aerosol in the 1993 vortex was similar to that in 1992. In 1993, surface areas were 10 - 20 mu m(2) cm(-3) and volumes 1 - 3 mu m(3) cm(-3). In 1995 three of five nights were within the polar vortex. The volcanic aerosol had decreased to 3 - 7 mu m(2) cm(-3) and 0.1 - 0.4 mu m(3) cm(-3). The top of the volcanic aerosol layer in both years was near 500 K potential temperature (similar to 20 km). A thick nitric acid and water PSC was observed in January 1995. In the thickest region of this PSC nearly all CN were observed to be activated, and surface areas of 5 - 10 mu m(2) cm(-3) were calculated. The volumes observed in this PSC were closer to what would be expected for particles composed of nitric acid trihydrate than for ternary solution droplets. In 1993 the opposite was observed, the volumes in the thin PSC were closer to what would be expected for ternary solution droplets. C1 Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. NOAA, Boulder, CO 80303 USA. RP Deshler, T (reprint author), Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. NR 37 TC 31 Z9 31 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD MAY PY 1998 VL 30 IS 1 BP 11 EP 23 DI 10.1023/A:1006023729315 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 101AC UT WOS:000074846600003 ER PT J AU Reid, SJ Rex, M Von der Gathen, P Floisand, I Stordal, F Carver, GD Beck, A Reimer, E Kruger-Carstensen, R De Haan, LL Braathen, G Dorokhov, V Fast, H Kyro, E Gil, M Litynska, Z Molyneux, M Murphy, G O'Connor, F Ravegnani, F Varotsos, C Wenger, J Zerefos, C AF Reid, SJ Rex, M Von der Gathen, P Floisand, I Stordal, F Carver, GD Beck, A Reimer, E Kruger-Carstensen, R De Haan, LL Braathen, G Dorokhov, V Fast, H Kyro, E Gil, M Litynska, Z Molyneux, M Murphy, G O'Connor, F Ravegnani, F Varotsos, C Wenger, J Zerefos, C TI A study of ozone laminae using diabatic trajectories, contour advection and photochemical trajectory model simulations. SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE ozone laminae; mid-latitudes; ozone depletion ID POLAR VORTEX; LOWER STRATOSPHERE; WINTER; PARAMETERIZATION; MIDLATITUDES; PROFILE; WAVES; EDGE; AIR AB In this paper, we show that the rate of ozone loss in both polar and mid-latitudes, derived from ozonesonde and satellite data, has almost the same vertical distribution (although opposite sense) to that of ozone laminae abundance. Ozone laminae appear in the lower stratosphere soon after the polar vortex is established in autumn, increase in number throughout the winter and reach a maximum abundance in late winter or spring. We indicate a possible coupling between mid-winter, sudden stratospheric warmings (when the vortex is weakened or disrupted) and the abundance of ozone laminae using a 23-year record of ozonesonde data from the World Ozone Data Center in Canada combined with monthly-mean January polar temperatures at 30 hPa. Results are presented from an experiment conducted during the winter of 1994/95, in phase II of the Second European Stratospheric And Mid-latitude Experiment (SESAME), in which 93 ozone-enhanced laminae of polar origin observed by ozonesondes at different time and locations are linked by diabatic trajectories, enabling them to be probed twice or more. It is shown that, in general, ozone concentrations inside laminae fall progressively with time, mixing irreversibly with mid-latitude air on time-scales of a few weeks. A particular set of laminae which advected across Europe during mid February 1995 are examined in detail. These laminae were observed almost simultaneously at seven ozonesonde stations, providing information on their spatial scales. The development of these laminae has been modelled using the Contour Advection algorithm of Norton (1994), adding support to the concept that many laminae are extrusions of vortex air. Finally, a photochemical trajectory model is used to show that, if the air in the laminae is chemically activated, it will impact on mid-latitude ozone concentrations. An estimate is made of the potential number of ozone molecules lost each winter via this mechanism. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Alfred Wegener Inst Polar & Marine Res, D-14401 Potsdam, Germany. Norwegian Inst Air Res, N-2007 Kjeller, Norway. Univ Cambridge, Dept Chem, Ctr Atmospher Sci, Cambridge CB2 1EW, England. Free Univ Berlin, Inst Meteorol, D-12165 Berlin, Germany. Univ Calif Irvine, Irvine, CA 92717 USA. Cent Aerol Observ, Moscow, Russia. Atmospher Environm Serv, Downsview, ON, Canada. Finnish Meteorol Inst, Sodankyla Observ, Sodankyla, Finland. Inst Nacl Tecn Aerospacial, Madrid 28850, Spain. Ctr Aerol IMWM, PL-05119 Legionowo, Poland. Meteorol Off, Bracknell RB12 2SZ, Berks, England. Irish Meteorol Serv, Valentia Observ, Caherciveen, Co Kerry, Ireland. Univ Wales, Dept Phys, Aberystwyth, Dyfed, Wales. CNR, Fisbat Inst, Bologna, Italy. Univ Athens, Athens, Greece. Natl Univ Ireland Univ Coll Dublin, Dept Chem, Dublin 4, Ireland. Aristotelian Univ Salonika, Lab Atmospher Phys, GR-54006 Thessloniki, Greece. RP Reid, SJ (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Rex, Markus/A-6054-2009; Wenger, John/F-6662-2010; Ravegnani, Fabrizio/A-7800-2009; von der Gathen, Peter/B-8515-2009; Varotsos, Costas/H-6257-2013; OI Rex, Markus/0000-0001-7847-8221; Wenger, John/0000-0002-4109-976X; Ravegnani, Fabrizio/0000-0003-0735-9297; von der Gathen, Peter/0000-0001-7409-1556; Varotsos, Costas/0000-0001-7215-3610; Stordal, Frode/0000-0002-5190-6473 NR 34 TC 49 Z9 50 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD MAY PY 1998 VL 30 IS 1 BP 187 EP 207 DI 10.1023/A:1005836212979 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 101AC UT WOS:000074846600014 ER PT J AU Abdulagatov, IM Bazaev, AR Bazaev, EA Saidakhmedova, MB Ramazanova, AE AF Abdulagatov, IM Bazaev, AR Bazaev, EA Saidakhmedova, MB Ramazanova, AE TI Volumetric properties of near-critical and supercritical water plus pentane mixtures: Molar, excess, partial, and apparent volumes SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID VIRIAL-COEFFICIENTS; PHASE-EQUILIBRIA; HIGH-PRESSURES; AQUEOUS MIXTURES; DILUTE MIXTURES; N-HEXANE; + WATER; TEMPERATURES; METHANE; SYSTEMS AB We present new PVTx measurements for water (A) + pentane (B) mixtures at the critical temperature of water (T-C = 647.05 K) in the pressure range 4 MPa to 41 MPa at x(b) = 0, 0.028, 0.042, 0.061, 0.088, 0.184, 0.391, 0.694, and 1.0. The measurements were performed with a constant-volume piezometer. The sample was confined to a 36.8 cm(3) cylindrical cell of a corrosion-resistant steel alloy, provided with a steel ball for stirring. The cell was separated from the rest of the fill and pressure measurement system by a diaphragm-type null indicator. The temperature was measured by a 10 Ohm platinum resistance thermometer. The uncertainty in the temperature measurement is less than +/-5 mK. Pressure was measured by means of a dead-weight gauge with a precision of +/-2 kPa. The composition was determined with an uncertainty of +/-0.002 in mole fraction. The volume of the cell was corrected for temperature expansion and elastic deformation by means of the known expansion coefficients of the cell. Taking into account the errors of temperature, pressure, and concentration measurements, the total experimental uncertainty of density, delta rho, was estimated to be less than +/-0.5%. From the PVTx results, the excess, partial, and apparent molar volumes were determined. Analysis of the results for dilute water + pentane mixtures showed that partial molar volume of pentane (solute) and excess molar volume of the mixture near the critical point of pure water (solvent) exhibit the behavior predicted by theory. A nonclassical (scaled) asymptotic relation has been used for the analysis of the partial and molar volumes behavior along the critical isotherm-isobar. C1 Russian Acad Sci, Inst Geothermal Problems, Dagestan Sci Ctr, Makhachkala 367030, Dagestan, Russia. RP Abdulagatov, IM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. EM ilmutdin@boulder.nist.gov NR 35 TC 21 Z9 21 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 1998 VL 43 IS 3 BP 451 EP 458 DI 10.1021/je970287o PG 8 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA ZP614 UT WOS:000073771100035 ER PT J AU Kessler, WS Rothstein, LM Chen, DK AF Kessler, WS Rothstein, LM Chen, DK TI The annual cycle of SST in the eastern tropical Pacific, diagnosed in an ocean GCM SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; SEASONAL CYCLE; EQUATORIAL PACIFIC; MODEL SIMULATION; REDUCED GRAVITY; HEAT-FLUX; CIRCULATION; ATMOSPHERE; INSTABILITY; CURRENTS AB The annual onset of the east Pacific cold tongue is diagnosed in an ocean GCM simulation of the tropical Pacific. The model uses a mixed-layer scheme that explicitly simulates the processes of vertical exchange of heat and momentum with the deeper layers of the ocean; comparison with observations of temperature and currents shows that many important aspects of the model fields are realistic. As previous studies have found, the heat balance in the eastern tropical Pacific is notoriously complicated, and virtually every term in the balance plays a significant role at one time or another. However, despite many complications, the three-dimensional ocean advection terms in the cold tongue region tend to cancel each other in the annual cycle and, to first order, the variation of SST can be described as simply following the variation of net solar radiation at the sea surface (sun minus clouds). The cancellation is primarily between cooling due to equatorial upwelling and warming due to tropical instability waves, both of which are strongest in the second half of the year (when the winds are stronger). Even near the equator, where the ocean advection is relatively intense, the terms associated with cloudiness variations are among the largest contributions to the SST balance. The annual cycle of cloudiness transforms the semiannual solar cycle at the top of the atmosphere into a largely 1 cycle yr(-1) variation of insolation at the sea surface. However, the annual cycle of cloudiness appears closely tied to SST in coupled feedbacks (positive for low stratus decks and negative for deep cumulus convection), so the annual cycle of SST cannot be fully diagnosed in an ocean-only modeling context as in the present study. Zonal advection was found to be a relatively small influence on annual equatorial cold tongue variations; in particular, there was little direct (oceanic) connection between the Peru coastal upwelling and equatorial annual cycles. Meridional advection driven by cross-equatorial winds has been conjectured as a key factor leading to the onset of the cold tongue. The results suggest that the SST changes due to this mechanism are modest, and if meridional advection is in fact a major influence, then it must be through interaction with another process (such is a coupled feedback with stratus cloudiness). At present, it is not possible to evaluate this feedback quantitatively. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Columbia Univ, Lamont Doherty Earth Observ, New York, NY USA. RP Kessler, WS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM kessler@pmel.noaa.gov RI Chen, Dake/E-7082-2011 NR 45 TC 87 Z9 87 U1 1 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1998 VL 11 IS 5 BP 777 EP 799 DI 10.1175/1520-0442(1998)011<0777:TACOSI>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP526 UT WOS:000073762300001 ER PT J AU Luers, JK Eskridge, RE AF Luers, JK Eskridge, RE TI Use of radiosonde temperature data in climate studies SO JOURNAL OF CLIMATE LA English DT Article AB Ten of the most common radiosondes used throughout the world since 1960 have been evaluated concerning potential use of their temperature data for climate studies. The VIZ; Space Data Corp.; Chinese GZZ; Japanese RS2-80; Russian RKZ, MARS, and A-22; and Vaisala RS80, RS 12/15, and RS 18/21 radiosondes were evaluated by modeling the temperature of the sensing element relative to the temperature of the air in which it is immersed. The difference, designated as the temperature error, was calculated under various environmental conditions. Validation and sensitivity analysis studies were performed on each radiosonde model as a means of estimating the environmental parameters that influence the temperature error and the resulting accuracy of the day and nighttime temperature profiles. Environmental parameters to which some sondes were sensitive include cloud cover, surface temperature, solar angle, ambient temperature profile, blackbody temperature, and the ventilation velocity. The ventilation velocity was found to depend strongly on the position of the sensor in the balloon wake. It is believed that the results of these analyses provide the best guidelines available to anyone wishing to perform climate studies using radiosonde data. The research work presented in this paper indicates that climate trends can currently be estimated with a subset of the worldwide upper-air data. Trends can be calculated for monthly averaged, nighttime soundings with some confidence for the Vaisala RS80 (models not using the RSN80 and RSN86 corrections), Vaisala RS 12/15, Vaisala RS 18/21, Chinese GZZ (below 25 km), Russian RKZ, Russian MARS, and Russian A-22 (below 20 km) radiosonde models. The analysis presented in this paper shows that all of the above radiosondes have small errors in individual radiosonde soundings at night (< +/- 1 degrees C) and the errors of the monthly averaged data are estimated to be less than +/-0.5 degrees C, except for the A-22 (+/-0.8 degrees C). In addition, temperature data from the Japanese RS-2-80, the Russian A-22 above 20 km, Vaisala RS80 (RSN80 and RSN86 corrections applied), and VIZ can be made suitable for climate analysis if the appropriate temperature correction models are used to correct the data. C1 NOAA, Natl Climat Data Ctr, Asheville, NC 28801 USA. Univ Dayton, Res Inst, Dayton, OH 45469 USA. RP Eskridge, RE (reprint author), NOAA, Natl Climat Data Ctr, 151 Patton Ave, Asheville, NC 28801 USA. NR 26 TC 73 Z9 76 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1998 VL 11 IS 5 BP 1002 EP 1019 DI 10.1175/1520-0442(1998)011<1002:UORTDI>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA ZP526 UT WOS:000073762300015 ER PT J AU Hunt, FY Galler, MA Martin, JW AF Hunt, FY Galler, MA Martin, JW TI Microstructure of weathered paint and its relation to gloss loss: Computer simulation and modeling SO JOURNAL OF COATINGS TECHNOLOGY LA English DT Article ID COATINGS; FILMS AB The role of pigment particle size, pigment volume concentration, and dispersion in gloss loss of paint films on weathered surfaces is unclear. Because reproducible and cost effective data are difficult to obtain, an approach based on computer simulation and modeling is a promising and supplementary tool. We describe the simulation of a painted surface consisting of pigment particles of known size, pigment volume concentration and dispersion, situated in a binder that erodes over time due to exposure to ultraviolet radiation. Pigment particle size, geometry, pigment volume concentration, and pigment particle dispersion are parameters of the model. Our purpose is to illustrate how simulation can be used to aid the development of formulation strategies for the design of coatings with desirable gloss characteristics. C1 Natl Inst Stand & Technol, Div Math & Comp Sci, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. RP Hunt, FY (reprint author), Natl Inst Stand & Technol, Div Math & Comp Sci, Gaithersburg, MD 20899 USA. NR 12 TC 13 Z9 13 U1 0 U2 2 PU FEDERATION SOC COATING TECH PI BLUE BELL PA 492 NORRISTOWN ROAD, BLUE BELL, PA 19422 USA SN 0361-8773 J9 J COATING TECHNOL JI J. Coat. Technol. PD MAY PY 1998 VL 70 IS 880 BP 45 EP 54 DI 10.1007/BF02697837 PG 10 WC Chemistry, Applied; Materials Science, Coatings & Films SC Chemistry; Materials Science GA ZP541 UT WOS:000073763800007 ER PT J AU Ciannelli, L Brodeur, RD Buckley, TW AF Ciannelli, L Brodeur, RD Buckley, TW TI Development and application of a bioenergetics model for juvenile walleye pollock SO JOURNAL OF FISH BIOLOGY LA English DT Article DE bioenergetics; modelling; vertical migration; food consumption ID PERCH PERCA-FLAVESCENS; THERAGRA-CHALCOGRAMMA; FOOD-CONSUMPTION; VERTICAL-DISTRIBUTION; GADUS-MORHUA; BERING SEA; GROWTH; TEMPERATURE; PREDICTIONS; SALMON AB A bioenergetics model was parameterized for age-0 walleye pollock, Theragra chalcogramma, based on a synthesis of literature data. The sensitivity of the new parameters was tested by individual parameter perturbation (IPP) analysis. The model was applied to estimate individual and total cohort food consumption of age-0 pollock in two areas of high pollock density in the Gulf of Alaska during the summer of 1990. Total cohort consumption was compared with zooplankton biomass and production estimates for the same areas and times of the year. The model was also used to examine the bioenergetic implications of age-0 pollock diel vertical migration through a thermal gradient. During a 1-month bioenergetics simulation, individual daily consumption decreased from 16.0 to 6.0% of wet body weight. Daily ration estimates corresponded well with independent field estimates of daily ration for the same areas and time of the year. Comparison of total cohort consumption with prey availability (production and biomass) indicated minimal potential for food limitation. Bioenergetic optimization of growth can be a potential benefit of diel vertical migration to age-0 pollock, however more information on prey density and distribution is needed to test this hypothesis thoroughly. (C) 1998 The Fisheries Society of the British Isles. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Res Ctr, Seattle, WA 98115 USA. RP Ciannelli, L (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Res Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 43 TC 49 Z9 50 U1 2 U2 7 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD MAY PY 1998 VL 52 IS 5 BP 879 EP 898 DI 10.1111/j.1095-8649.1998.tb00589.x PG 20 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA ZQ597 UT WOS:000073884000002 ER PT J AU Duewer, DL Lalonde, SA Aubin, RA Fourney, RM Reeder, DJ AF Duewer, DL Lalonde, SA Aubin, RA Fourney, RM Reeder, DJ TI Interlaboratory comparison of autoradiographic DNA profiling measurements: Precision and concordance SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; DNA typing GM9947; GM9948; K562 cell line controls; electrophoresis; graphical data analysis; restriction fragment length polymorphism AB Knowledge of the expected uncertainty in restriction fragment length polymorphism (RFLP) measurements is required for confident exchange of such data among different laboratories. The total measurement uncertainty among all Technical Working Group for DNA Analysis Methods laboratories has previously been characterized and found to be acceptably small. Casework cell line control measurements provided by six Royal Canadian Mounted Police (RCMP) and 30 U.S. commercial, local, state, and Federal forensic laboratories enable quantitative determination of the within-laboratory precision and among-laboratory concordance components of measurement uncertainty typical of both sets of laboratories. Measurement precision is the same in the two countries for DNA fragments of size 1000 base pairs (bp) to 10,000 bp. However, the measurement concordance among the RCMP laboratories is clearly superior to that within the U.S. forensic community. This result is attributable to the use of a single analytical protocol in all RCMP laboratories. Concordance among U.S. laboratories cannot be improved through simple mathematical adjustments. Community-wide efforts focused on improved concordance may be the most efficient mechanism for further reduction of among-laboratory RFLP measurement uncertainty, should the resources required to fully evaluate potential cross-jurisdictional matches become burdensome as the number of RFLP profiles on record increases. C1 Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Royal Canadian Mounted Police, Forens Lab, Biol Sect, Edmonton, AB T5V 1B7, Canada. Royal Canadian Mounted Police, Cent Forens Lab, DNA Methods & Data Base Unit, Ottawa, ON K1G 3M8, Canada. Hlth Canada, Sir FG Banting Res Ctr, Life Sci Div Biotechnol, Ottawa, ON K1A 0L2, Canada. Natl Inst Stand & Technol, Div Biotechnol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Reeder, DJ (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Room A353, Gaithersburg, MD 20899 USA. RI Duewer, David/B-7410-2008 NR 19 TC 12 Z9 12 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD MAY PY 1998 VL 43 IS 3 BP 465 EP 471 PG 7 WC Medicine, Legal SC Legal Medicine GA ZN879 UT WOS:000073692700002 PM 9608684 ER PT J AU Sergeev, VA Shukhtina, MA Rasinkangas, R Korth, A Reeves, GD Singer, HJ Thomsen, MF Vagina, LI AF Sergeev, VA Shukhtina, MA Rasinkangas, R Korth, A Reeves, GD Singer, HJ Thomsen, MF Vagina, LI TI Event study of deep energetic particle injections during substorm SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PROTON DRIFT ECHOES; GEOSYNCHRONOUS ORBIT; INNER MAGNETOSPHERE; SYNCHRONOUS ORBIT; MAGNETIC-FIELD; CURRENT WEDGE; GROWTH-PHASE; DYNAMICS; ONSET; CRRES AB The origin of multiple energetic particle injections into the inner magnetosphere is addressed using a rare opportunity of measuring the energetic particle fluxes at different radial distances under known electric and magnetic fields. During a strong substorm on February 10, 1991, the CRRES spacecraft measured E and B fields and high-energy particle fluxes near the magnetic equator at r similar to 5 R-e, whereas particle injections, their azimuthal locations, and some other parameters were simultaneously monitored by three geostationary spacecraft and ground networks. We show a multitude of impulsive short-duration injection events which correlate with 1-2 min long pulses of dawn-dusk electric field. The observations suggest that some E field pulses recorded deep in the inner magnetosphere were fast magnetosonic waves radiated by the current disruption region. This supports the concept of impulsive dissipation event as an elementary building block of substorm expansion. Furthermore, our modeling results indicate that most of the flux variations of energetic particles can be explained by the global convective transport and corresponding particle acceleration. However, we emphasize that, depending on particle spectra and radial flux gradient, one can observe either flux increase, or decrease, or no variation (often seen in different energy ranges simultaneously and at the same point) as a response to the electric field pulse. Both the cloud of injected particles and magnetic field dipolarization region had a sharp inner boundary (injection front) which propagated inward at the convection speed. We document the complicated structure of this front, consisting of a diamagnetic hot proton layer followed by the dipolarixation front which contains enhanced energetic electron fluxes. Further study is required to understand hom common this structure is and, if common, how it may be formed. C1 St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Oulu, Dept Phys Sci, FIN-90571 Oulu, Finland. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Sergeev, VA (reprint author), St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. RI Shukhtina, Maria/K-3783-2013; Reeves, Geoffrey/E-8101-2011; Sergeev, Victor/H-1173-2013 OI Shukhtina, Maria/0000-0001-7892-8392; Reeves, Geoffrey/0000-0002-7985-8098; Sergeev, Victor/0000-0002-4569-9631 NR 54 TC 42 Z9 43 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1998 VL 103 IS A5 BP 9217 EP 9234 DI 10.1029/97JA03686 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL412 UT WOS:000073430300013 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80302 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80302 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1998 VL 103 IS A5 BP 9363 EP 9365 DI 10.1029/98JA00759 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZL412 UT WOS:000073430300027 ER PT J AU Sanders, JN Chenoweth, SA Schwarz, FP AF Sanders, JN Chenoweth, SA Schwarz, FP TI Effect of metal ion substitutions in concanavalin A on the binding of carbohydrates and on thermal stability SO JOURNAL OF INORGANIC BIOCHEMISTRY LA English DT Article DE cadmium; carbohydrate binding; concanavalin A; differential scanning calorimetry; isothermal titration calorimetry; thermal stability ID LENS-CULINARIS LECTIN; PISUM-SATIVUM LECTIN; THERMODYNAMICS; MONOSACCHARIDE; DENATURATION; RESOLUTION; PROTEIN AB Isothermal titration calorimetry (ITC) measurements were performed on the binding of alpha methyl-D-mannopyranoside, D-mannopyranose, alpha methyl-D-glucopyranoside, and D-glucopyranose (Glu) to cobalt, nickel, and cadmium substituted concanavalin A (Con A) derivatives at pH = 6.9 and at 25 degrees C. The metal substituted Con A derivatives consisted of Co2+, Ni2+, and Cd2+ substituted for the Mn2+ ion in the S1 site of Con A which is about 12.8 Angstrom away from the center of the carbohydrate binding site of Con A. The thermodynamic quantities determined from the ITC measurements were the same for most of the binding reactions indicating that the structure of the binding site in solution is the same for all the Con A derivatives in solution and that the presence of different 2+ metal ions in the S1 site has little effect on the binding reactions. Differential scanning calorimetry scans of solutions of the metal ion derivatives of Con-A show that the thermodynamics of the unfolding transition for the cobalt and nickel substituted derivatives are the same as for Con A: they dissociate from tetramers into monomers as they unfold around 85 degrees C. The cadmium substituted Con A derivative, however, exhibits an additional transition around 93 degrees C which also appears following the addition of Cd2+ to the Con A solutions. This transition results from the unfolding of a species of Con A with Cd2+ substituted into a third binding site at the monomeric interface of the Con A tetramer. The higher stability of this species is not only exemplified by the higher thermal transition temperature but also by the lack of dissociation as it unfolds. Cd2+ is released from the S3 site upon decreasing the pH from 6.9 to 6.4. ITC measurements on the binding reaction of Cd2+ to Con A show that the binding enthalpy is 40.2 +/- 0.4 kJ mol(-1) at 23.4 +/- 0.2 degrees C and the binding reaction exhibits a large heat capacity change of 1.43 +/- 0.41 kJ mol(-1) K-1. (C) 1998 Elsevier Science Inc. All rights reserved. C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Schwarz, FP (reprint author), NIST, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 22 TC 23 Z9 23 U1 1 U2 10 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0162-0134 J9 J INORG BIOCHEM JI J. Inorg. Biochem. PD MAY PY 1998 VL 70 IS 2 BP 71 EP 82 DI 10.1016/S0162-0134(98)00016-6 PG 12 WC Biochemistry & Molecular Biology; Chemistry, Inorganic & Nuclear SC Biochemistry & Molecular Biology; Chemistry GA ZY543 UT WOS:000074632900001 PM 9666569 ER PT J AU Marsh, ER Yantek, DS Davies, MA Gilsinn, DE AF Marsh, ER Yantek, DS Davies, MA Gilsinn, DE TI Simulation and measurement of chatter in diamond turning SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID PREDICTION; PARAMETERS AB This paper considers chatter in diamond turning of aluminum. A nonlinear chip area model is developed for use with the classic single degree of freedom cutting model. The chip area model is formulated as a function of the change in depth of cut between consecutive passes. This function is shown to be highly dependent on the quadratic term when turning the diameter of cylindrical workpieces with round-nosed diamond tools. The cutting model is further extended to include an impact disturbance to the cutting process. The recent research in ultra-precision machining is incorporated to properly account for the rise in specific cutting energy at extremely light depths of cut. Simulations of the resulting tool displacement show close agreement with experimental measurements. C1 Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NIST, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. RP Marsh, ER (reprint author), Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NR 17 TC 5 Z9 5 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD MAY PY 1998 VL 120 IS 2 BP 230 EP 235 DI 10.1115/1.2830118 PG 6 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA ZR681 UT WOS:000074003100003 ER PT J AU Ivester, R Danai, K AF Ivester, R Danai, K TI Automatic tuning and regulation of injection molding by the Virtual Search Method SO JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB Methodical specification of process inputs for injection molding is hindered by the absence of accurate analytical models. For these processes, the input variables are assigned either by trial and error, based on heuristic knowledge of an experienced operator, or by statistical Design of Experiments (DOE) methods which construct a comprehensive empirical model between the inputs and part quality attributes. In this paper an iterative method of input selection (tuning) referred to as the Virtual Search Method (VSM) is introduced that conducts most of the search for appropriate machine inputs in a 'virtual' environment provided by an approximate input-output (I-O) model. VSM applies the inputs to the process only when it has exhausted the search based on the current I-O model. It evaluates the quality of inputs from the search and updates the I-O model for the next round of search based on measurements of parr quality attributes (e.g., size tolerances and surface integrity) after each process iteration. According to this strategy, VSM updates the model only when needed, and thus selectively develops the model as required for timing the process. This approach has been shown to lead to shorter tuning sessions than required by DOE methods. C1 Univ Massachusetts, Dept Mech & Ind Engn, Amherst, MA 01003 USA. RP Ivester, R (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 31 TC 5 Z9 5 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-1357 J9 J MANUF SCI E-T ASME JI J. Manuf. Sci. Eng.-Trans. ASME PD MAY PY 1998 VL 120 IS 2 BP 323 EP 329 DI 10.1115/1.2830130 PG 7 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA ZR681 UT WOS:000074003100015 ER PT J AU Josell, D Gonzalez, EJ White, GS AF Josell, D Gonzalez, EJ White, GS TI Correcting errors in the theory for mirage-effect measurements SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SPECTROSCOPY AB Errors are noted in two publications on the theory for Mirage-effect measurements of the thermal diffusivity of materials. The works include theory for interpreting Mirage experiments on homogeneous samples mounted on a support with ambient (typically air) above and theory for interpreting Mirage experiments on coated substrates with ambient both above and below. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Josell, D (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 6 TC 6 Z9 6 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1998 VL 13 IS 5 BP 1117 EP 1119 DI 10.1557/JMR.1998.0156 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA ZJ975 UT WOS:000073272500007 ER PT J AU Lee, YE Kim, YJ Kim, HJ AF Lee, YE Kim, YJ Kim, HJ TI Thickness dependence of microstructural evolution of ZnO films deposited by rf magnetron sputtering SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID THIN-FILMS; PREFERRED ORIENTATION; ION-BOMBARDMENT; METAL-FILMS; ZINC-OXIDE; GROWTH; TARGET AB The microstructural evolution, including preferred orientation and surface morphology, of ZnO films deposited by rf magnetron sputtering was investigated with increasing film thickness. Preferred orientation of the ZnO films changed from (0002) --> (10 (1) over bar 1) --> (11 (2) over bar 0), and fine and dense columnar grains also changed to large elongated grains with increasing thickness. Such selective texture growth was explained with an effect of highly energetic species bombardment on the growing film surface. The relationship between preferred orientation change and microstructural evolution was also discussed. C1 Seoul Natl Univ, Interuniv Semicond Res Ctr, Seoul 151742, South Korea. Seoul Natl Univ, Sch Mat Sci & Engn, Seoul 151742, South Korea. Kyonggi Univ, Dept Elect & Adv Mat Engn, Suwon 440760, South Korea. RP Lee, YE (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. RI Kim, Hyeong Joon/F-6151-2013 NR 29 TC 37 Z9 37 U1 1 U2 5 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAY PY 1998 VL 13 IS 5 BP 1260 EP 1265 DI 10.1557/JMR.1998.0180 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA ZJ975 UT WOS:000073272500031 ER PT J AU Chu, PM Wetzel, SJ Lafferty, WJ Perrin, A Flaud, JM Arcas, P Guelachvili, G AF Chu, PM Wetzel, SJ Lafferty, WJ Perrin, A Flaud, JM Arcas, P Guelachvili, G TI Line intensities for the 8-mu m bands of SO2 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID LASER SPECTROSCOPY; SULFUR-DIOXIDE; (SO2)-S-32-O-16; POSITIONS; MOLECULES AB Using both high-resolution (R = 0.003 cm(-1)) and medium-resolution (R = 0.12 cm(-1)) Fourier transform spectroscopy, it has been possible to measure accurately a large set of individual line intensities for the v(1) and v(3) bands of SO2 in the 950-1400 cm(-1) spectral region. These intensities were introduced into a least-squares fit calculation allowing one to obtain the expansion of the transition moment operator of the v(1) and v(3) bands. For these intensity calculations, the theoretical model takes into account the vibration-rotation interactions linking the upper levels involved in the v(1), 2v(2), and v(3) interacting SO2 bands. Finally, a synthetic spectrum of the 8-mu m SO2 bands has been generated using the dipole moment expansion determined in this work and the molecular parameters and the Hamiltonian matrix given in a previous analysis, (C) 1998 Academic Press. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. Universite Paris Sud, Ctr Orsay, CNRS, Lab Phys Mol & Applicat, F-91405 Orsay, France. RP Chu, PM (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 34 TC 36 Z9 36 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 1998 VL 189 IS 1 BP 55 EP 63 DI 10.1006/jmsp.1997.7517 PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA ZM048 UT WOS:000073499500007 ER EF