FN Thomson Reuters Web of Science™ VR 1.0 PT J AU WILLIAMS, T WOODARD, S JUANG, JN AF WILLIAMS, T WOODARD, S JUANG, JN TI ATTITUDE-CONTROL USING GIMBALED THRUSTERS SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB Spacecraft slewing maneuvers are typically controlled by means of thrusters which are pulsed on and off as required. Unfortunately, as spacecraft become larger and more flexible, these thruster transients are more and more likely to excite undesirable flexible modes. This paper presents a preliminary analysis of a novel slewing technique which is designed to avoid such problems. In this approach, the control thrusters remain on throughout the maneuver; they are gimbaled according to a feedback scheme based on the instantaneous pointing angle and rate of the spacecraft. The resulting closed-loop dynamics are highly nonlinear, making a stability analysis quite challenging. As the first part of such a study, a characterization of the equilibria of the system is used to obtain acceptable values for the control gains. Lyapunov techniques are then employed to prove global asymptotic stability. Finally, the properties of the controller are illustrated by means of simulation results. C1 NASA,LANGLEY RES CTR,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23681. NASA,LANGLEY RES CTR,SPACECRAFT CONTROLS BRANCH,HAMPTON,VA 23681. RP WILLIAMS, T (reprint author), UNIV CINCINNATI,DEPT AEROSP ENGN,CINCINNATI,OH 45221, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JUL-SEP PY 1993 VL 41 IS 3 BP 399 EP 410 PG 12 WC Engineering, Aerospace SC Engineering GA MG705 UT WOS:A1993MG70500007 ER PT J AU EINAUDI, F FINNIGAN, JJ AF EINAUDI, F FINNIGAN, JJ TI WAVE-TURBULENCE DYNAMICS IN THE STABLY STRATIFIED BOUNDARY-LAYER SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID INTERNAL GRAVITY-WAVE AB New data obtained at the Boulder Atmospheric Observatory (BAO) has been compared with a linear stability analysis of the background atmospheric state as measured by rawinsonde ascents. Good agreement was obtained between measured wave parameters such as wavelength, period, and vector phase velocity, and the eigenvalues of the linear solution, but linear eigenvectors scaled by measured pressure at the base of the BAO tower less well with measurement. An investigation of the wave kinetic energy budget revealed that buoyant production of wave energy was a significant gain despite the strong stability (Ri greater than or similar to 5). Further analysis of the budgets of wave heat flux and temperature variance revealed the essential role of wave-turbulence interaction in maintaining a large amplitude temperature wave and countergradient wave heat flux. A consideration of the turbulent kinetic energy budget showed many of the same features as the wave budget. A comparison with earlier near-neutral and stable cases analyzed in comparable detail suggests that countergradient wave heat fluxes maintained by nonlinear wave-turbulence interaction and an essential transfer of kinetic energy from wave to turbulence may be generic features of such situations. A mechanism for maintenance of turbulence by waves in strongly stratified boundary layers is described, which emphasizes that the time-mean Richardson number is an irrelevant parameter at such times. In the analysis of the data, general methods are described for extracting wave signals from nonstationary turbulence records and for assessing the statistical significance of the waveform so derived. C1 CSIRO,CTR ENVIRONM MECH,GPO BOX 821,CANBERRA,ACT 2601,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHER LAB,GREENBELT,MD 20771. NR 23 TC 56 Z9 60 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1993 VL 50 IS 13 BP 1841 EP 1864 DI 10.1175/1520-0469(1993)050<1841:WTDITS>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LL512 UT WOS:A1993LL51200001 ER PT J AU CANUTO, VM MINOTTI, F AF CANUTO, VM MINOTTI, F TI STRATIFIED TURBULENCE IN THE ATMOSPHERE AND OCEANS - A NEW SUBGRID MODEL SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID LARGE-EDDY-SIMULATION; BOUNDARY-LAYER; TEMPERATURE SPECTRA; MIXED LAYERS; DIFFUSION; FLUID AB Turbulence in a stratified medium is studied with emphasis on stable stratification, as it occurs in the atmosphere and oceans, and on the construction of a subgrid model (SGS) for use in large eddy simulation (LES). The two basic assumptions of all SGS models are 1) that the unresolved scales are isotropic and 2) that they can be described by a Kolmogorov spectrum and are no longer valid in a stably stratified medium. Generation of gravity waves invalidates the second assumption, while the damping of vertical motion induces a degree of anisotropy considerably higher than in unstably stratified flows. First, Weinstock's model is used to find that the energy dissipation rate epsilon decreases with stability. By contrast, the dissipation rate epsilon(theta) of temperature variance increases with stability. The effect of shear on the subgrid scales is neglected. Second, because of the higher anisotropy of stably stratified flows, even the most complete SGS model presently in use must be enlarged to include new higher-order terms. A new second-order closure model is proposed in which the three components of the flux u(i)thetaBAR can be obtained by inverting a 3 x 3 matrix and u(i)u(j)BAR can be obtained by inverting a 6 x 6 matrix. An approximate procedure is suggested, however, to avoid the 6 x 6 matrix inversion and yet account for anisotropic production. The kinetic energy e is a solution of a differential equation. It is also shown that in a deep LES, where the buoyancy scales are fully resolved, the standard models for epsilon and epsilon(theta) are probably adequate, whereas in a shallow LES, where the buoyancy range may not be fully resolved, the above effects on epsilon and epsilon(theta) must be accounted for. It would be of interest to perform both a shallow and a deep LES so as to check the predictions of the model proposed here. Preliminary results indicate that the (total) kinetic energy dissipation length scale increase with stability, in accordance with LES results but in disagreement with Deardorff's model that suggested a decrease of all dissipation scales in presence of stratification. RP CANUTO, VM (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 40 TC 31 Z9 32 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1993 VL 50 IS 13 BP 1925 EP 1935 DI 10.1175/1520-0469(1993)050<1925:STITAA>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LL512 UT WOS:A1993LL51200007 ER PT J AU PIERCE, RB FAIRLIE, TDA AF PIERCE, RB FAIRLIE, TDA TI OBSERVATIONAL EVIDENCE OF PREFERRED FLOW REGIMES IN THE NORTHERN-HEMISPHERE WINTER STRATOSPHERE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID PROBABILITY DENSITY DISTRIBUTION; QUASI-BIENNIAL OSCILLATION; INTERANNUAL VARIABILITY; MODEL; CIRCULATION; ATMOSPHERE AB Ten years of stratospheric geopotential height data are analyzed in an attempt to determine whether there are preferred flow regimes in the Northern Hemisphere winter stratosphere. The data are taken from Stratospheric Sounding Units on board NOAA satellites. The probability density estimate of the amplitude of the wavenumber 1 10-mb height is found to be bimodal. The density distribution is composed of a dominant large-amplitude mode and a less frequent low-amplitude mode. When the wavenumber 1 10-mb height data are projected onto the phase plane defined by the 10-mb zonal-mean winds and wavenumber 1 100-mb heights, three preferred regimes are evident. The small-amplitude mode separates into a strong zonal wind-weak wave regime and a weak zonal wind-weak wave regime. The large-amplitude mode is an intermediate zonal wind-strong wave regime. Transitions between the large-amplitude regime and the weak zonal wind-weak wave regime are found to be associated with major stratospheric warmings. The clustering of the stratospheric data into the preferred flow regimes is interpreted in light of the bifurcation properties of the Holton and Mass model. The interannual variability of the Northern Hemisphere winter stratosphere is interpreted in terms of the relative frequency of the observed preferred regimes. RP PIERCE, RB (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,THEORET STUDIES BRANCH,MAIL STOP 401B,HAMPTON,VA 23681, USA. RI Pierce, Robert Bradley/F-5609-2010 OI Pierce, Robert Bradley/0000-0002-2767-1643 NR 26 TC 16 Z9 16 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 1 PY 1993 VL 50 IS 13 BP 1936 EP 1949 DI 10.1175/1520-0469(1993)050<1936:OEOPFR>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LL512 UT WOS:A1993LL51200008 ER PT J AU SCHUBERT, S SUAREZ, M PARK, CK MOORTHI, S AF SCHUBERT, S SUAREZ, M PARK, CK MOORTHI, S TI GCM SIMULATIONS OF INTRASEASONAL VARIABILITY IN THE PACIFIC NORTH-AMERICAN REGION SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODEL; 40-50 DAY OSCILLATION; STATIONARY WAVES; GEOPOTENTIAL HEIGHT; TROPICAL ATMOSPHERE; TIME SCALES; LIFE-CYCLES; EL-NINO; ANOMALIES; PROPAGATION AB General circulation model (GCM) simulations of low-frequency variability with time scales of 20 to 70 days are analyzed for the Pacific sector during boreal winter. The GCM's leading mode in the upper-tropospheric zonal wind is associated with fluctuations of the East Asian jet; this mode resembles, in both structure and amplitude, the Pacific/North American (PNA) pattern found in the observations on these time scales. In both the model and observations the PNA anomaly is characterized by 1) a linear balance in the upper-tropospheric vorticity budget with no significant Rossby wave source in the tropics, 2) a barotropic conversion of kinetic energy from the time mean Pacific jet, and 3) a north /south displacement of the Pacific storm track. In the GCM, the latter is associated with synoptic eddy heat flux and latent heat anomalies that appear to contribute to a strong lower-tropospheric source of wave activity over the North Pacific. This is in contrast to the observations, which show only a weak source of wave activity in this region. The GCM produces 60% of the total observed Pacific sector low-frequency zonal wind variance. About one-third of the missing variability appears to be due to unrealistic simulations of the Madden-Julian oscillation; the remainder is characterized in the variance spectrum as a deficit in the overall level of ''background'' variability. The nature of this missing background variability is unclear. C1 NASA, GODDARD SPACE FLIGHT CTR, GSFC, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. RP SCHUBERT, S (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GSFC, GODDARD LAB ATMOSPHERE, CODE 9103, GREENBELT, MD 20771 USA. NR 41 TC 22 Z9 23 U1 0 U2 0 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 1993 VL 50 IS 13 BP 1991 EP 2007 DI 10.1175/1520-0469(1993)050<1991:GSOIVI>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LL512 UT WOS:A1993LL51200011 ER PT J AU NARAYANAN, SR SHEN, DH SURAMPUDI, S ATTIA, AI HALPERT, G AF NARAYANAN, SR SHEN, DH SURAMPUDI, S ATTIA, AI HALPERT, G TI ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY OF LITHIUM-TITANIUM DISULFIDE RECHARGEABLE CELLS SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID AC IMPEDANCE; ELECTROLYTE; PARAMETERS; FILMS AB The two-terminal alternating current impedance of lithium-titanium disulfide (Li/TiS2) rechargeable cells has been studied as a function of frequency, state-of-charge, and extended cycling. Analysis based on a plausible equivalent circuit model for the Li/TiS2 cell leads to evaluation of kinetic parameters for the various physicochemical processes occurring at the electrode/electrolyte interfaces. To investigate the causes of cell degradation during extended cycling, the parameters evaluated for cells cycled five times have been compared with the parameters of cells that have been cycled over 600 times. The findings are that the combined ohmic resistance of the electrolyte and electrodes suffers a ten-fold increase after extended cycling, while the charge-transfer resistance and diffusional impedance at the TiS2/electrolyte interface are not significantly affected. The results reflect the morphological change and increase in area of the anode due to cycling. The study also shows that overdischarge of a cathode-limited cell causes a decrease in the diffusion coefficient of the lithium ion in the cathode. The study demonstrates the value of electrochemical impedance spectroscopy in investigating failure mechanisms. The approach and methodology followed here can be extended to other rechargeable lithium battery systems. RP NARAYANAN, SR (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 35 TC 63 Z9 64 U1 2 U2 36 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUL PY 1993 VL 140 IS 7 BP 1854 EP 1861 DI 10.1149/1.2220729 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA LL842 UT WOS:A1993LL84200014 ER PT J AU GOLDSMITH, S MORENO, JC GRIEM, HR COHEN, L KNAUER, J AF GOLDSMITH, S MORENO, JC GRIEM, HR COHEN, L KNAUER, J TI SPECTROSCOPIC STUDY OF PLASMAS PRODUCED BY A LASER EQUIPPED WITH DISTRIBUTED PHASE PLATES SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID SATELLITE SPECTRA; FUSION PELLETS; IONS; ILLUMINATION; UNIFORMITY; LAYERS AB The spectra emitted by Al and Si laser-produced plasmas were recorded in the region of 18-350 angstrom. The bandlike structures observed near the Al XI and Si XII 2p-3d transitions at 52 and 44 angstrom, respectively, are identified as Be-like dielectronic satellite transitions in Al and Si. The plasmas were produced with the Omega laser system at the Laboratory for Laser Energetics at the University of Rochester. Typical laser pulse lengths were 650 ps at a laser wavelength of 351 nm, with an intensity of 5-9 X 10(14) W/cm2. The spherical targets employed in these experiments consisted of solid-glass spheres coated with a 2-mum layer of Al and an outer layer of parylene 0-8 mum thick, illuminated by 24 laser beams equipped with distributed phase plates (DPP's) to improve the uniformity of illumination. The dielectronic transitions associated with the observed bands belong to the transition arrays 1S(2)2pnl-1S(2)3dnl, where n is the principal quantum number (greater than 2) and l is the azimuthal quantum number of the spectator electron. The observation of Be-like dielectronic transitions suggests that this emission occurs from a lower temperature (T(e) greater than or similar to 100 eV) and higher density (N(e) greater than or similar to 8 X 10(21) cm-3) plasma region. The influence of DPP's on the emission of these dielectronic satellites is discussed. C1 TEL AVIV UNIV,RAYMOND & BEVERLY SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14623. RP GOLDSMITH, S (reprint author), UNIV MARYLAND,PLASMA RES LAB,COLL PK,MD 20742, USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUL PY 1993 VL 10 IS 7 BP 1137 EP 1142 DI 10.1364/JOSAB.10.001137 PG 6 WC Optics SC Optics GA LL532 UT WOS:A1993LL53200001 ER PT J AU PARK, C AF PARK, C TI REVIEW OF CHEMICAL-KINETIC PROBLEMS OF FUTURE NASA MISSIONS .1. EARTH ENTRIES SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID MOLECULE; ABINITIO; STATES; C-3 RP PARK, C (reprint author), NASA,AMES RES CTR,AEROTHERMODYNAM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 51 TC 263 Z9 267 U1 2 U2 18 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1993 VL 7 IS 3 BP 385 EP 398 DI 10.2514/3.431 PG 14 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA LN868 UT WOS:A1993LN86800001 ER PT J AU AMUNDSEN, RM AF AMUNDSEN, RM TI THERMAL-ANALYSIS AND TEST OF LASER REFERENCE CAVITY SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID ACTIVE FREQUENCY STABILIZATION; ND-GGG; LINEWIDTH; HZ AB SUNLITE is a space-based experiment which uses an external reference cavity to provide a stable frequency reference for a terahertz laser oscillator. Thermal stability of the cavity is a key factor in attaining a stable narrow-linewidth laser beam. This article describes the thermal stability requirements on the cavity design and detailed thermal analysis performed, as well as thermal testing that was performed on a prototype. Analytical thermal models were correlated to the test data. Cavity design was improved based on lessons learned in the prototype; additional modeling of the current design is presented. Suggestions for improving similar high-precision thermal tests are given. RP AMUNDSEN, RM (reprint author), NASA,LANGLEY RES CTR,DIV SYST ENGN,THERMAL ANAL SECT,HAMPTON,VA 23665, USA. NR 6 TC 0 Z9 0 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1993 VL 7 IS 3 BP 517 EP 523 DI 10.2514/3.448 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA LN868 UT WOS:A1993LN86800018 ER PT J AU VIJAYARAGHAVAN, D BREWE, DE KEITH, TG AF VIJAYARAGHAVAN, D BREWE, DE KEITH, TG TI EFFECT OF OUT-OF-ROUNDNESS ON THE PERFORMANCE OF A DIESEL-ENGINE CONNECTING-ROD BEARING SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID CAVITATION AB In this paper, the dynamic performance of the Ruston and Hornsby VEB diesel engine connecting-rod bearing with circular and out-of-round profiles is analyzed. The effect of cavitation is considered by using a cavitation algorithm, which mimics JFO boundary conditions. The effect of mass inertia is accounted for by solving coupled nonlinear equations of motion. The journal profiles considered are circular, elliptical semi elliptical and three lobe epicycloid. The predicted journal trajectory and other performance parameters for one complete load cycle are presented for all of the out-of-round profiles and are also compared with the predictions for the circular bearing. C1 UNIV TOLEDO,TOLEDO,OH 43606. RP VIJAYARAGHAVAN, D (reprint author), NASA,LEWIS RES CTR,USA AVIAT SYST COMMAND,CLEVELAND,OH 44135, USA. NR 18 TC 8 Z9 8 U1 1 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD JUL PY 1993 VL 115 IS 3 BP 538 EP 543 DI 10.1115/1.2921671 PG 6 WC Engineering, Mechanical SC Engineering GA LN859 UT WOS:A1993LN85900032 ER PT J AU CROOK, AJ GREITZER, EM TAN, CS ADAMCZYK, JJ AF CROOK, AJ GREITZER, EM TAN, CS ADAMCZYK, JJ TI NUMERICAL-SIMULATION OF COMPRESSOR ENDWALL AND CASING TREATMENT FLOW PHENOMENA SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 37TH INTERNATIONAL CONGRESS AND EXPOSITION ON GAS TURBINE AND AEROENGINE CY JUN 01-04, 1992 CL COLOGNE, GERMANY ID 3-DIMENSIONAL VISCOUS-FLOW; TIP-CLEARANCE FLOW; ROTOR AB A numerical study is presented of the flow in the endwall region of a compressor blade row, in conditions of operation with both smooth and grooved endwalls. The computations are first compared to velocity field measurements in a cantilevered stator/rotating hub configuration to confirm that the salient features are captured. Computations are then interrogated to examine the tip leakage flow structure since this is a dominant feature of the endwall region. In particular, the high blockage that can exist near the endwalls at the rear of a compressor blade passage appears to be directly linked to low total pressure fluid associated with the leakage flow. The fluid dynamic action of the grooved endwall, representative of the casing treatments that have been most successful in suppressing stall, is then simulated computationally and two principal effects are identified. One is suction of the low total pressure, high blockage fluid at the rear of the passage. The second is energizing of the tip leakage flow, most notably in the core of the leakage vortex, thereby suppressing the blockage at its source. C1 MIT,CAMBRIDGE,MA 02139. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CROOK, AJ (reprint author), ALLISON GAS TURBINE DIV,INDIANAPOLIS,IN 46206, USA. NR 20 TC 52 Z9 59 U1 3 U2 10 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 1993 VL 115 IS 3 BP 501 EP 512 DI 10.1115/1.2929280 PG 12 WC Engineering, Mechanical SC Engineering GA LP012 UT WOS:A1993LP01200014 ER PT J AU HATHAWAY, MD CHRISS, RM WOOD, JR STRAZISAR, AJ AF HATHAWAY, MD CHRISS, RM WOOD, JR STRAZISAR, AJ TI EXPERIMENTAL AND COMPUTATIONAL INVESTIGATION OF THE NASA LOW-SPEED CENTRIFUGAL-COMPRESSOR FLOW-FIELD SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 37TH INTERNATIONAL CONGRESS AND EXPOSITION ON GAS TURBINE AND AEROENGINE CY JUN 01-04, 1992 CL COLOGNE, GERMANY AB An experimental and computational investigation of the NASA Low-Speed Centrifugal Compressor (LSCC) flow field has been conducted using laser anemometry and Dawes' three dimensional viscous code. The experimental configuration consists of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational analysis, and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the rotor as well as surface flow visualization along the impeller blade surfaces provide independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake, which is characteristic of unshrouded centrifugal compressors. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP HATHAWAY, MD (reprint author), USA,RES LAB,VEHICLE PROPULS DIRECTORATE,CLEVELAND,OH 44135, USA. NR 27 TC 38 Z9 42 U1 1 U2 10 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 1993 VL 115 IS 3 BP 527 EP 542 DI 10.1115/1.2929285 PG 16 WC Engineering, Mechanical SC Engineering GA LP012 UT WOS:A1993LP01200017 ER PT J AU BOYNTON, JL TABIBZADEH, R HUDSON, ST AF BOYNTON, JL TABIBZADEH, R HUDSON, ST TI INVESTIGATION OF ROTOR BLADE ROUGHNESS EFFECTS ON TURBINE PERFORMANCE SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 37TH INTERNATIONAL CONGRESS AND EXPOSITION ON GAS TURBINE AND AEROENGINE CY JUN 01-04, 1992 CL COLOGNE, GERMANY AB The cold air test program was completed on the SSME (Space Shuttle Main Engine) HPFTP (High-Pressure Fuel Turbopump) turbine with production nozzle vane rings and polished coated rotor blades with a smooth surface finish of 30 muin. (0.76 mum) rms (root mean square). The smooth blades were polished by an abrasive flow machining process. The test results were compared with the air test results from production rough-coated rotor blades with a surface finish of up to 400 muin. (10.16 mum) rms. Turbine efficiency was higher for the smooth blades over the entire range tested. Efficiency increased 2.1 percentage points at the SSME 104 percent RPL (Rated Power Level) conditions. This efficiency improvement could reduce the SSME HPFTP turbine inlet temperature by 57 R (32 K), increasing turbine durability. The turbine flow parameter increased and the midspan outlet swirl angle became more axial with the smooth rotor blades. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP BOYNTON, JL (reprint author), ROCKWELL INT CORP,ROCKETDYNE DIV,CANOGA PK,CA 91303, USA. NR 7 TC 25 Z9 26 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 1993 VL 115 IS 3 BP 614 EP 620 DI 10.1115/1.2929298 PG 7 WC Engineering, Mechanical SC Engineering GA LP012 UT WOS:A1993LP01200026 ER PT J AU KENNY, TW KAISER, WJ PODOSEK, JA ROCKSTAD, HK REYNOLDS, JK VOTE, EC AF KENNY, TW KAISER, WJ PODOSEK, JA ROCKSTAD, HK REYNOLDS, JK VOTE, EC TI MICROMACHINED TUNNELING DISPLACEMENT TRANSDUCERS FOR PHYSICAL SENSORS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 39TH NATIONAL SYMP OF THE AMERICAN VACUUM SOC CY NOV 09-13, 1992 CL CHICAGO, IL SP AMER VACUUM SOC ID CAPACITIVE PRESSURE SENSOR; SILICON; ACCELEROMETER; MICROSCOPY; NOISE; DETECTOR AB We have designed and constructed a series of tunneling sensors which take advantage of the extreme position sensitivity of electron tunneling. In these sensors, a tunneling displacement transducer, based on scanning tunneling microscopy principles, is used to detect the signal-induced motion of a sensor element. Through the use of high-resonant frequency mechanical elements for the transducer, sensors may be constructed which offer wide bandwidth, and are robust and easily operated. Silicon micromachining may be used to fabricate the transducer elements, allowing integration of sensor and control electronics. Examples of tunneling accelerometers and infrared detectors will be discussed. In each case, the use of the tunneling transducer allows miniaturization of the sensor as well as enhancement of the sensor RP KENNY, TW (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 33 TC 16 Z9 16 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1993 VL 11 IS 4 BP 797 EP 802 DI 10.1116/1.578351 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA LP007 UT WOS:A1993LP00700014 ER PT J AU PIKE, WT KSENDZOV, A FATHAUER, RW GEORGE, T AF PIKE, WT KSENDZOV, A FATHAUER, RW GEORGE, T TI MICROSTRUCTURE AND LIGHT-EMISSION IN STAIN-ETCHED SI1-XGEX ALLOYS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 20TH ANNUAL CONF ON THE PHYSICS AND CHEMISTRY OF SEMICONDUCTOR INTERFACES CY JAN 25-29, 1993 CL WILLIAMSBURG, VA SP AMER VACUUM SOC, AMER PHYS SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, XEROX CORPORATE RES & TECHNOL ID VISIBLE LUMINESCENCE; POROUS SILICON; WAFERS; SI AB The microstructure of stain-etched porous Si1-xGex layers has been studied using transmission electron microscopy (TEM) and chemical microanalysis and the results correlated with photoluminescence (PL) from the porous regions. High-resolution TEM imaging and diffraction indicate that the porous layers are mostly composed of amorphous material with some crystallites at the porous-substrate interface. Energy dispersive x-ray and electron energy-loss spectroscopies have been used to chemically profile cross sections of the layers and obtain porosity measurements at the nanometer level. All the layers have a porosity of between 70% and 80% and are substantially Ge rich compared to the unetched material. The PL from the porous layers drops off sharply with increasing Ge content of the stain-etched alloy and the redshift expected in the quantum-confinement model of light emission is absent. However the data is consistent with a simple model which assumes that the light-emitting species in the porous layers contains only a few atoms of Si. RP PIKE, WT (reprint author), JET PROP LAB,CTR SPACE MICROELECTR,PASADENA,CA 91109, USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1993 VL 11 IS 4 BP 1401 EP 1406 DI 10.1116/1.586949 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA LT450 UT WOS:A1993LT45000030 ER PT J AU FATHAUER, RW GEORGE, T JONES, EW PIKE, WT KSENDZOV, A VASQUEZ, RP AF FATHAUER, RW GEORGE, T JONES, EW PIKE, WT KSENDZOV, A VASQUEZ, RP TI NOVEL SI-BASED SUPERLATTICES CONSISTING OF ALTERNATING LAYERS OF CRYSTALLINE SI AND POROUS AMORPHOUS SI1-XGEX ALLOYS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 20TH ANNUAL CONF ON THE PHYSICS AND CHEMISTRY OF SEMICONDUCTOR INTERFACES CY JAN 25-29, 1993 CL WILLIAMSBURG, VA SP AMER VACUUM SOC, AMER PHYS SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, XEROX CORPORATE RES & TECHNOL ID SILICON; WAFERS AB Superlattices consisting of alternating layers of crystalline Si and porous amorphous Si1-xGex have been studied. These are fabricated by immersing mesa structures of molecular-beam-epitaxy grown Si/Si0.7Ge0.3 superlattices in an HF:HNO3:H2O solution. A high selectivity in the pore formation leads to lateral penetration of pores almost-equal-to 0.7 mum into 5-nm-thick Si0.7Ge0.3 layers. The effect of the etch on layers with differing alloy composition, thickness, and strain has been examined. Homogeneous strain has been identified as an important factor in establishing the selectivity of the etch, but other factors clearly play important roles as well. RP FATHAUER, RW (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 10 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 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1993 VL 11 IS 4 BP 1518 EP 1520 DI 10.1116/1.586962 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA LT450 UT WOS:A1993LT45000053 ER PT J AU RICH, DH RAMMOHAN, K TANG, Y LIN, HT MASERJIAN, J GRUNTHANER, FJ LARSSON, A BORENSTAIN, SI AF RICH, DH RAMMOHAN, K TANG, Y LIN, HT MASERJIAN, J GRUNTHANER, FJ LARSSON, A BORENSTAIN, SI TI ABSORPTION MODULATION INDUCED BY ELECTRON-BEAM EXCITATION OF STRAINED IN0.2GA0.8AS/GAAS MULTIPLE-QUANTUM WELLS SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 20TH ANNUAL CONF ON THE PHYSICS AND CHEMISTRY OF SEMICONDUCTOR INTERFACES CY JAN 25-29, 1993 CL WILLIAMSBURG, VA SP AMER VACUUM SOC, AMER PHYS SOC, USN, OFF NAVAL RES, USAF, OFF SCI RES, XEROX CORPORATE RES & TECHNOL ID SPATIAL LIGHT MODULATORS; DOPING SUPERLATTICES; CATHODOLUMINESCENCE; SEMICONDUCTORS; MICROSCOPY; DEFECTS; GAAS AB The effects of excess carrier generation on excitonic absorption phenomena in nipi-doped In0.2Ga0.8As/GaAs multiple quantum wells (MQWs) was examined using a novel technique called electron beam-induced absorption modulation imaging. The nipi-doping induced barrier height is determined by measuring the frequency response of the absorption modulation as a function of temperature and employing a model which is based on thermal excitation of carriers in the limit of Boltzmann statistics. Spatial steps in the absorption modulation which correlate with the positions and orientation of dark line defects imaged in cathodoluminescence are observed. These results indicate the existence of defects in the MQWs which impede the ambipolar diffusive transport of the spatially separated electron-hole plasma. C1 JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. CHALMERS UNIV TECHNOL,DEPT OPTOELECTR & ELECT MEASUREMENTS,S-41296 GOTHENBURG,SWEDEN. JERUSALEM COLL TECHNOL,IL-91160 JERUSALEM,ISRAEL. RP RICH, DH (reprint author), UNIV SO CALIF,DEPT MAT SCI & ENGN,PHOTON MAT & DEVICES LAB,LOS ANGELES,CA 90089, USA. RI Schaff, William/B-5839-2009; Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1993 VL 11 IS 4 BP 1717 EP 1722 DI 10.1116/1.586511 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA LT450 UT WOS:A1993LT45000091 ER PT J AU BAUMEISTER, KJ KREIDER, KL AF BAUMEISTER, KJ KREIDER, KL TI MODAL ELEMENT METHOD FOR SCATTERING AND ABSORBING OF SOUND BY 2-DIMENSIONAL BODIES SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article AB The modal element method for acoustic scattering from a two-dimensional body is presented. The body may be acoustically soft (absorbing) or hard (reflecting). The infinite computational region is divided into two subdomains-the bounded finite element domain, which is characterized by complicated geometry and/or variable material properties, and the surrounding unbounded homogeneous domain. The acoustic pressure field is represented approximately in the finite element domain by a finite element solution, and is represented analytically by an eigenfunction expansion in the homogeneous domain. The two solutions are coupled by the continuity of pressure and velocity across the interface between the two subdomains. Also, for hard bodies, a compact modal ring grid system is introduced for which computing requirements are drastically reduced. In this paper, analysis for two-dimensional scattering from solid and coated (acoustically treated) bodies is presented, and several simple numerical examples are discussed. In addition, criteria are presented for determining the number of modes to accurately resolve the scattered pressure field from a solid cylinder as a function of the frequency of the incoming wave and the radius of the cylinder. RP BAUMEISTER, KJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 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 SN 1048-9002 J9 J VIB ACOUST JI J. Vib. Acoust.-Trans. ASME PD JUL PY 1993 VL 115 IS 3 BP 314 EP 323 DI 10.1115/1.2930351 PG 10 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA LP496 UT WOS:A1993LP49600014 ER PT J AU BALAZS, GH FUJIOKA, R FUJIOKA, C AF BALAZS, GH FUJIOKA, R FUJIOKA, C TI MARINE TURTLE FECES ON HAWAIIAN BEACHES SO MARINE POLLUTION BULLETIN LA English DT Article ID CHELONIA-MYDAS; GREEN TURTLE AB Faeces of the green turtle, Chelonia mydas, washed ashore in large numbers at a beach park in Hawaii over a 40-day period in 1989. The formed pellets were originally misidentified as being from pigs or humans, and therefore were perceived as a pollutant of potential health hazard to humans. However, bacteriological analysis of the nearshore waters indicated low and legally acceptable levels of faecal coliforms and enterococci. Similar diminished levels were also found in direct cultures of the fresh pellets. Green turtle faeces have been known to drift ashore in Hawaii, but never in the quantities recorded during this short-term event. The reason for the occurrence could not be determined, but several possible explanations are given. C1 UNIV HAWAII, WATER RESOURCES RES CTR, HONOLULU, HI 96822 USA. RP NOAA, NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, HONOLULU LAB, 2570 DOLE ST, HONOLULU, HI 96822 USA. NR 5 TC 14 Z9 14 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUL PY 1993 VL 26 IS 7 BP 392 EP 394 DI 10.1016/0025-326X(93)90187-O PG 3 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA LP461 UT WOS:A1993LP46100009 ER PT J AU SHIH, TH LUMLEY, JL AF SHIH, TH LUMLEY, JL TI REMARKS ON TURBULENT CONSTITUTIVE RELATIONS SO MATHEMATICAL AND COMPUTER MODELLING LA English DT Article ID RENORMALIZATION-GROUP; REYNOLDS STRESS; SHEAR FLOWS; DIFFUSION AB The paper demonstrates that the concept of turbulent constitutive relations introduced by Lumley [1] can be used to construct general models for various turbulent correlations. Some of Generalized Cayley-Hamilton formulas for relating tensor products of higher Extension to tensor products of lower Extension are introduced. The combination of dimensional analysis and invariant theory can lead to ''turbulent constitutive relations'' (or general turbulence models) for, in principle, any turbulent correlations. As examples, the constitutive relations for Reynolds stresses and scalar fluxes are derived. The results are consistent with ones from RNG theory and two-scale DIA method, but with a more general form. C1 CORNELL UNIV,ITHACA,NY 14853. RP SHIH, TH (reprint author), NASA,LEWIS RES CTR,ICOMP,CTR MODELING TURBULENCE & TRANSIT,CLEVELAND,OH 44135, USA. NR 9 TC 21 Z9 23 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0895-7177 J9 MATH COMPUT MODEL JI Math. Comput. Model. PD JUL PY 1993 VL 18 IS 2 BP 9 EP 16 DI 10.1016/0895-7177(93)90002-G PG 8 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA MC068 UT WOS:A1993MC06800002 ER PT J AU AGGARWAL, MD WANG, WS CHOI, J CHANG, KJ SHIELDS, AW PENN, BG FRAZIER, DO AF AGGARWAL, MD WANG, WS CHOI, J CHANG, KJ SHIELDS, AW PENN, BG FRAZIER, DO TI A NOVEL BRIDGMAN-STOCKBARGER MELT GROWTH SYSTEM FOR ORGANIC NONLINEAR-OPTICAL MATERIALS SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Note ID CRYSTALS AB A modified Bridgman-Stockbarger crystal growth system has been designed and fabricated for relatively low-temperature (up to 250-degrees-C) nonlinear optical organic materials. The novel feature is that the crystal melt surface can be viewed from any direction and the temperature gradient between the hot and cold zone can be adjusted at any time. The ampoule can be lowered at a rate as slow as 0.1 mm h-1. The temperature can be maintained to a precision of +/-0.1-degrees-C. High-quality single crystals of benzil have been successfully grown using this system. C1 ALABAMA A&M UNIV, DEPT CHEM, NORMAL, AL 35762 USA. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, HUNTSVILLE, AL 35812 USA. RP ALABAMA A&M UNIV, DEPT PHYS, NORMAL, AL 35762 USA. NR 6 TC 9 Z9 9 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD JUL PY 1993 VL 4 IS 7 BP 793 EP 795 DI 10.1088/0957-0233/4/7/015 PG 3 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA LQ945 UT WOS:A1993LQ94500015 ER PT J AU MAJUMDAR, BS NEWAZ, GM ELLIS, JR AF MAJUMDAR, BS NEWAZ, GM ELLIS, JR TI EVOLUTION OF DAMAGE AND PLASTICITY IN TITANIUM-BASED, FIBER-REINFORCED COMPOSITES SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID METAL MATRIX COMPOSITES AB The inelastic deformation mechanisms were evaluated for a model titanium-based, fiber-reinforced composite: a beta titanium alloy (Ti-15V-3Al-3Cr-3Sn) reinforced with SiC (SCS-6) fibers. The primary emphasis of this article is to illustrate the sequence in which damage and plasticity evolved for this system. The mechanical responses and the results of detailed microstructural evaluations for the [0]8, [90]8, and [+/-45]2s laminates are provided. It is shown that the characteristics of the reaction zone around the fiber play a very important role in the way damage and plasticity evolve, particularly in the microyield regime of deformation, and must be included in any realistic constitutive model. Fiber-matrix debonding was a major damage mode for the off-axis systems. The tension test results are also compared with the predictions of a few constitutive models. C1 NASA,LEWIS RES CTR,FATIGUE & FAILURE BRANCH,CLEVELAND,OH 44135. BATTELLE MEM INST,COLUMBUS,OH 43201. RP MAJUMDAR, BS (reprint author), UNIVERSAL ENERGY SYST INC,DAYTON,OH 45432, USA. NR 28 TC 42 Z9 42 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD JUL PY 1993 VL 24 IS 7 BP 1597 EP 1610 DI 10.1007/BF02646599 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA LK917 UT WOS:A1993LK91700013 ER PT J AU TEWARI, SN SHAH, R CHOPRA, MA AF TEWARI, SN SHAH, R CHOPRA, MA TI THERMOSOLUTAL CONVECTION AND MACROSEGREGATION CAUSED BY SOLUTE REJECTION AT CELL DENDRITE TIPS SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID DIRECTIONAL SOLIDIFICATION; BINARY ALLOY; GROWTH; INTERFACE; TRANSITION; STABILITY; MODEL; MELT AB Thermosolutal convection caused by the solute build up ahead of growing arrays of cells and dendrites results in macrosegregation along the length of Pb-Sn alloy (10 to 58 wt pct Sn) specimens when they are directionally solidified in a positive thermal gradient (melt on top, solid below, and gravity pointing down). At a constant thermal gradient, the extent of macrosegregation increases with decreasing growth speed as the microstructure changes from dendritic to cellular and to planar. An empirical parameter, effective partition coefficient (k(eff)), obtained from the dependence of the longitudinal macrosegregation on fraction distance solidified can be used to represent the extent of macrosegregation. The extent of macrosegregation appears to be related to a parameter, [g(C(t) - C0) D(l)/RC0]1/2, where C0 is the tin content of the alloy, C(t) is the tin content of melt at the array tips, R is the growth speed, D(l) is the diffusivity of tin in the melt, and g is the acceleration due to gravity. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP TEWARI, SN (reprint author), CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115, USA. NR 32 TC 32 Z9 33 U1 0 U2 11 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD JUL PY 1993 VL 24 IS 7 BP 1661 EP 1669 DI 10.1007/BF02646605 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA LK917 UT WOS:A1993LK91700019 ER PT J AU ASTHANA, R AF ASTHANA, R TI ON THE ANCHORING OF SOLIDS AT CURVED FLUID INTERFACES SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Note ID FREE-ENERGY ANALYSES; SMALL PARTICLES; FORCE C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP ASTHANA, R (reprint author), CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115, USA. NR 15 TC 4 Z9 4 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD JUL PY 1993 VL 24 IS 7 BP 1673 EP 1677 DI 10.1007/BF02646607 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA LK917 UT WOS:A1993LK91700021 ER PT J AU KORMANYOS, BK REBEIZ, GM AF KORMANYOS, BK REBEIZ, GM TI A 26 TO 220 GHZ HARMONIC MIXER-RECEIVER SO MICROWAVE JOURNAL LA English DT Article AB A wideband mm-wave harmonic mixer-receiver double dagger has been developed using a wideband integrated-circuit antenna, a back-to-back Schottky-barrier diode chip and microwave circuit design. The design is planar, simple to build and yields excellent performance from 26 to 180 GHz. Application areas include wideband early warning systems, wideband search and rescue systems and the extension of spectrum analyzer and power meter range to the mm-wave region. C1 UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109. NR 10 TC 1 Z9 1 U1 0 U2 0 PU HORIZON HOUSE-MICROWAVE PI NORWOOD PA 685 CANTON ST, NORWOOD, MA 02062 SN 0192-6225 J9 MICROWAVE J JI Microw. J. PD JUL PY 1993 VL 36 IS 7 BP 103 EP 108 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA LN848 UT WOS:A1993LN84800006 ER PT J AU JOHNSON, DR ZAPOTOCNY, TH REAMES, FM WOLF, BJ PIERCE, RB AF JOHNSON, DR ZAPOTOCNY, TH REAMES, FM WOLF, BJ PIERCE, RB TI A COMPARISON OF SIMULATED PRECIPITATION BY HYBRID ISENTROPIC-SIGMA AND SIGMA-MODELS SO MONTHLY WEATHER REVIEW LA English DT Article ID NUMERICAL INVESTIGATIONS; MOISTURE TRANSPORT; SENSITIVITY; CLIMATE AB The primary objectives of this study are threefold: 1) to compare simulations of dry and moist baroclinic development from 10- and 22-layer hybrid isentropic-sigma coordinate models with those from 11-, 27-, and 35-layer sigma coordinate models; 2) to examine the ability of the models to transport water vapor and simulate equivalent potential temperature theta(e); and 3) to compare predictions of the timing, location, and amount of precipitation. A model's capability to predict precipitation stems from the accuracy of its simulation of the joint distribution of mass, potential temperature, and water vapor throughout the model domain. In a series of experiments to compare simulations of precipitation, several analytic distributions of water vapor are specified initially. The water vapor distributions include a ''cylinder'' extending vertically throughout the atmosphere and ''lenses'' within isentropic, sigma, and isobaric layers. The effects of increased horizontal resolution are also studied. Results indicate that when the relative humidity is vertically uniform through a substantial extent of the atmosphere, all the models produce very similar precipitation distributions. However, when water vapor is confined to relatively shallow layers, the ability of the sigma coordinate models to simulate the timing, location, and amount of precipitation is severely compromised. Furthermore, the 10-layer hybrid model conserves theta(e) to a higher degree of accuracy and simulates a more realistic evolution of precipitation even when compared to results from sigma models with increased vertical and horizontal resolution. In all instances, the experiments demonstrate that advantages reside in prediction of precipitation with the hybrid model. Both theoretical and conceptual bases for these differences are provided. C1 NASA,LANGLEY RES CTR,THEORET STUDIES BRANCH,HAMPTON,VA 23665. RP JOHNSON, DR (reprint author), UNIV WISCONSIN,CTR SPACE SCI & ENGN,DEPT ATMOSPHER & OCEAN SCI,1225 W DAYTON ST,MADISON,WI 53706, USA. RI Pierce, Robert Bradley/F-5609-2010 OI Pierce, Robert Bradley/0000-0002-2767-1643 NR 23 TC 33 Z9 33 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1993 VL 121 IS 7 BP 2088 EP 2114 DI 10.1175/1520-0493(1993)121<2088:ACOSPB>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LK949 UT WOS:A1993LK94900014 ER PT J AU EGALON, CO ROGOWSKI, RS AF EGALON, CO ROGOWSKI, RS TI EXACT SOLUTION FOR PHASE-SHIFT OF TE AND TM MODES IN AN OPTICAL-FIBER DUE TO AXIAL STRAIN SO OPTICAL ENGINEERING LA English DT Article DE CIRCULAR OPTICAL FIBERS; ELECTROMAGNETIC THEORY; OPTICAL FIBER DISTRIBUTED SENSORS; OPTICAL FIBER STRAIN SENSORS; STEP INDEX PROFILE FIBERS; MODAL PHASE SHIFT AB Axial strain on an optical fiber can be determined by monitoring the phase shift of a variety of optical fiber sensors. The exact analytical solutions for optical fields that propagate in a circular core optical fiber are used here to determine the phase shifts that occur for TE and TM modes due to axial strain. Whenever an optical fiber is stressed, the optical path length, the index of refraction, and the propagation constant of each fiber mode change. In consequence, the modal phase term betaz of the fields is shifted by an amount DELTAphi. In certain cases, it is desirable to control the phase sensitivity to make fibers that are either more or less sensitive to strain. We show that it can be accomplished by choosing appropriate fiber parameters. RP EGALON, CO (reprint author), NASA,LANGLEY RES CTR,NONDESTRUCT EVALUAT SCI BRANCH,MS 231,HAMPTON,VA 23681, USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JUL PY 1993 VL 32 IS 7 BP 1638 EP 1643 DI 10.1117/12.138768 PG 6 WC Optics SC Optics GA LM100 UT WOS:A1993LM10000026 ER PT J AU LEE, AY AF LEE, AY TI NUMERICAL-SOLUTION OF TIME-DELAYED OPTIMAL-CONTROL PROBLEMS WITH TERMINAL INEQUALITY CONSTRAINTS SO OPTIMAL CONTROL APPLICATIONS & METHODS LA English DT Article DE TIME-DELAYED OPTIMAL CONTROL PROBLEMS; TERMINAL INEQUALITY CONSTRAINTS; PADE APPROXIMATION; COMBINED PARAMETER AND FUNCTION OPTIMIZATION ALGORITHM ID OPTIMAL-CONTROL COMPUTATION; LAG SYSTEMS AB In this short communication we consider an approximation scheme for solving time-delayed optimal control problems with terminal inequality constraints. Time-delayed problems are characterized by variables x(t-tau) with a time-delayed argument. In our scheme we use a Pade approximation to determine a differential relation for y(t), an augmented state that represents x(t-tau). Terminal inequality constraints, if they exist, are converted to equality constraints via Valentine-type unknown parameters. The merit of this approach is that existing, well-developed optimization algorithms may be used to solve the transformed problems. Two linear/non-linear time-delayed optimal control problems are solved to establish its usefulness. RP LEE, AY (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 8 TC 12 Z9 12 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0143-2087 J9 OPTIM CONTR APPL MET JI Optim. Control Appl. Methods PD JUL-SEP PY 1993 VL 14 IS 3 BP 203 EP 210 PG 8 WC Automation & Control Systems; Operations Research & Management Science; Mathematics, Applied SC Automation & Control Systems; Operations Research & Management Science; Mathematics GA LW595 UT WOS:A1993LW59500005 ER PT J AU SCHATTEN, KH AF SCHATTEN, KH TI HIDDEN-VARIABLE MODEL FOR THE BOHM EINSTEIN-PODOLSKY-ROSEN EXPERIMENT SO PHYSICAL REVIEW A LA English DT Article AB We consider a hidden-variable model for the Einstein, Podolsky, and Rosen experiment [Phys. Rev. 47,777 (1935)] as modified by Bohm [Quantum Theory (Prentice-Hall, Englewood Cliffs, NJ, 1951)). We provide a nonlocal random-vector model that mimics the same statistical behavior as quantum mechanics and conforms with Bell's theorem. Angular momentum conservation appears to require the nonlocal correlations. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 4 TC 3 Z9 3 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 1993 VL 48 IS 1 BP 103 EP 104 DI 10.1103/PhysRevA.48.103 PG 2 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100021 ER PT J AU BALIYAN, KS BHATIA, AK AF BALIYAN, KS BHATIA, AK TI OSCILLATOR-STRENGTHS FOR THE TRANSITIONS IN CA XIII SO PHYSICAL REVIEW A LA English DT Article ID ISOELECTRONIC SEQUENCE; CROSS-SECTIONS; WAVE-FUNCTIONS; EXCITATION; PROGRAM; OXYGEN AB The absorption oscillator strengths for a number of transitions among LS states and the fine-structure levels calculated using extensive configuration interaction in the wave functions are reported. The relativistic results are obtained adopting an intermediate-coupling scheme through the use of the terms of the Breit-Pauli Hamiltonian. In general, there is very good agreement between length and velocity forms of the oscillator strengths and the energies obtained using these wave functions compare very well with the observed values. The comparison of the oscillator strengths calculated in the present work with the other available calculations shows good agreement. Also reported are accurate results for many astrophysically important transitions involving quintet states. It is noted that spin-spin and spin-other-orbit terms of the Breit-Pauli Hamiltonian have considerable effect on the f values for the intercombination transitions. RP BALIYAN, KS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. OI /0000-0003-0180-8231 NR 23 TC 2 Z9 2 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 1993 VL 48 IS 1 BP 250 EP 257 DI 10.1103/PhysRevA.48.250 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100040 ER PT J AU BHATIA, AK HO, YK AF BHATIA, AK HO, YK TI COMPLEX-COORDINATE CALCULATIONS OF DOUBLY-EXCITED (1,3)D(E) RESONANT STATES OF PS(-) SO PHYSICAL REVIEW A LA English DT Article ID POSITRONIUM NEGATIVE-ION; HYLLERAAS FUNCTIONS; ATOM; PS AB Doubly excited 1,3D(e) resonant states in positronium ions Ps- are calculated by using a method of complex-coordinate rotation. Resonance parameters (both resonance positions and widths) for doubly excited states associated with the n = 2 and 3 thresholds of positronium atoms are evaluated using elaborate Hylleraas-type functions. In addition to Feshbach-type resonances lying below the Ps thresholds, we have also identified two 1D(e) shape resonances lying above the n = 3 Ps threshold. C1 LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. RP BHATIA, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Ho, Yew Kam/F-7912-2012 NR 21 TC 19 Z9 19 U1 0 U2 2 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 1993 VL 48 IS 1 BP 264 EP 267 DI 10.1103/PhysRevA.48.264 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100042 ER PT J AU SMITH, SJ CHUTJIAN, A MITROY, J TAYAL, SS HENRY, RJW MAN, KF MAWHORTER, RJ WILLIAMS, ID AF SMITH, SJ CHUTJIAN, A MITROY, J TAYAL, SS HENRY, RJW MAN, KF MAWHORTER, RJ WILLIAMS, ID TI EXCITATION CROSS-SECTIONS FOR THE NS S-2-]NP P-2 RESONANCE TRANSITIONS IN MG+ (N = 3) AND ZN+ (N = 4) USING ELECTRON-ENERGY-LOSS AND MERGED-BEAMS METHODS SO PHYSICAL REVIEW A LA English DT Article ID IMPACT EXCITATION; 42S->42P TRANSITION; ION SCATTERING; MONOCHROMATOR; COLLISIONS; ABSOLUTE; EFFICIENCIES; FORBIDDEN; SPECTRA; SYSTEMS AB Electron-excitation cross sections are reported for the 3S 2S-->3p 2P(h,k) resonance transition in Mg+ at energies from threshold (4.43 eV) to approximately 9 times threshold (40.0 eV). The electron-energy-loss merged-beams technique used in these measurements is described in detail. In addition, the method of separating contributions of the elastically scattered (Coulomb) and the inelastically scattered electrons in the present Mg+ case and previously reported Zn+ results [Phys. Rev. Lett. 67, 30 (1991)] is described. Comparisons in the experimental energy range are made for Mg+ with the two five-state close-coupling theoretical calculations carried out herein, and with other published close-coupling, distorted-wave, and semiempirical calculations. The present Mg+ cross sections and Zn+ cross sections from earlier measurements are tabulated. C1 NO TERR UNIV, FAC SCI, CASUARINA, NT 0811, AUSTRALIA. CLARK ATLANTA UNIV, DEPT PHYS, ATLANTA, GA 30314 USA. MIAMI UNIV, DEPT PHYS, OXFORD, OH 45056 USA. POMONA COLL, DEPT PHYS & ASTRON, CLAREMONT, CA 91711 USA. QUEENS UNIV BELFAST, DEPT PURE & APPL PHYS, BELFAST BT7 1NN, ANTRIM, NORTH IRELAND. RP JET PROP LAB, PASADENA, CA 91109 USA. RI Mitroy, Jim/B-6371-2009; Mitroy, James/N-2162-2013 OI Mitroy, James/0000-0002-2477-1251 NR 73 TC 31 Z9 31 U1 0 U2 2 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 1993 VL 48 IS 1 BP 292 EP 309 DI 10.1103/PhysRevA.48.292 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100046 ER PT J AU ORIENT, OJ CHUTJIAN, A MARTUS, KE MURAD, E AF ORIENT, OJ CHUTJIAN, A MARTUS, KE MURAD, E TI OBSERVATION OF CN A-]X AND B-]X EMISSIONS IN GAS-PHASE COLLISIONS OF FAST O(P-3) ATOMS WITH HCN SO PHYSICAL REVIEW A LA English DT Article ID VEHICLE GLOW; SHUTTLE GLOW; RECOMBINATION AB Optical emissions in single-collision reactions of fast (5-25-eV translational energy) O(3P) atoms with HCN have been measured in a crossed-beam geometry. The emissions were observed in the wavelength range 345-430 and 550-825 nm, and were identified as the CN(B 2SIGMA+-->X 2SIGMA+) and CN(A 2PI(i)-->X 2SIGMA+) transitions, respectively. The experimental B-->X vibrational bands were found to fit a synthetic spectrum of CN at a vibrational temperature of 7000 K (0.60 eV) and a rotational temperature of 2000 K (0.17 eV). The A-->X spectra were simulated in terms of known Franck-Condon factors for that band system. The energy threshold for the CN(B-->X) emission was measured to be 7.4+/-0.8 eV (lab) or 4.6+/-0.5 eV (c.m.), which agrees with the energy threshold for the reaction O(3P)+HCN(X)-->OH(X)+CN(B). C1 PHILLIPS LAB,WSSI,BEDFORD,MA 01731. RP ORIENT, OJ (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 20 TC 15 Z9 15 U1 0 U2 3 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 1993 VL 48 IS 1 BP 427 EP 431 DI 10.1103/PhysRevA.48.427 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100061 ER PT J AU ZETNER, PW LI, Y TRAJMAR, S AF ZETNER, PW LI, Y TRAJMAR, S TI CHARGE-CLOUD ALIGNMENT IN THE ELECTRON-IMPACT EXCITATION OF BA-138(...6S6P P-1(1)) SO PHYSICAL REVIEW A LA English DT Article ID PHOTON COINCIDENCE EXPERIMENTS; LASER-EXCITED ATOMS; SUPERELASTIC SCATTERING; COHERENCE PARAMETERS; CROSS-SECTIONS; ANGULAR-CORRELATIONS; HELIUM COLLISIONS; STEPWISE ELECTRON; ORIENTATION; SODIUM AB We have determined charge-cloud alignment parameters P(l)+ and gamma for electron-impact excitation of the (6s2 S-1(0)) to (6s6p P-1(1)) transition in Ba-138 by measuring the superelastic scattering of electrons from laser-excited Ba-138. Four electron-impact energies were studied and scattering-angle coverage in each case was sufficient to allow the observation of pronounced structure in the behavior of these parameters. Comparison of our measurements with two distorted-wave theories [R. E. H. Clark, J. Abdallah, Jr., G. Csanak, and S. P. Kramer, Phys. Rev. A 40, 2935 (1989); R. Srivastava, T. Zuo, R. P. McEachran, and A. D. Stauffer, J. Phys. B 25, 3709 (1992)] reveals generally excellent agreement except at the lowest impact energy studied where these theories fail completely to reproduce the observed behavior of P(l)+. Our low-impact-energy data have also been compared with a close-coupling calculation [I. I. Fabrikant, Izv. Akad. Nauk Latv. SSR, Ser. Fiz. Tekhn. 6, 11 (1985)] which qualitatively reproduces the observed behavior of P(l)+ and gamma but fails to give quantitative agreement. C1 JET PROP LAB,PASADENA,CA 91109. RP ZETNER, PW (reprint author), UNIV MANITOBA,DEPT PHYS,WINNIPEG R3T 2N2,MANITOBA,CANADA. NR 39 TC 25 Z9 25 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 1993 VL 48 IS 1 BP 495 EP 504 DI 10.1103/PhysRevA.48.495 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA LM341 UT WOS:A1993LM34100069 ER PT J AU ABID, R SPEZIALE, CG AF ABID, R SPEZIALE, CG TI PREDICTING EQUILIBRIUM STATES WITH REYNOLDS STRESS CLOSURES IN CHANNEL FLOW AND HOMOGENEOUS SHEAR-FLOW SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID TURBULENCE; MODELS AB Turbulent channel flow and homogeneous shear flow have served as basic building block flows for the testing and calibration of Reynolds stress models. In this paper, a direct theoretical connection is made between homogeneous shear flow in equilibrium and the log layer of fully developed turbulent channel flow. It is shown that if a second-order closure model of the standard type is calibrated to yield good equilibrium values for homogeneous shear flow, it will also yield good results for the log layer of channel flow provided that the Rotta coefficient is not too far removed from one. Most of the commonly used second-order closure models introduce an ad hoc wall reflection term in order to mask deficient predictions for the log layer of channel flow that arise either from an inaccurate calibration of homogeneous shear flow or from the use of a Rotta coefficient that is too large. Illustrative model calculations are presented to demonstrate this point which has important implications for turbulence modeling. C1 NASA,INST COMP APPLICAT SCI & ENGN,LANGLEY RES CTR,HAMPTON,VA 23681. RP ABID, R (reprint author), NASA,LANGLEY RES CTR,HIGH TECHNOL CORP,HAMPTON,VA 23681, USA. NR 16 TC 41 Z9 42 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD JUL PY 1993 VL 5 IS 7 BP 1776 EP 1782 DI 10.1063/1.858852 PG 7 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LH294 UT WOS:A1993LH29400025 ER PT J AU TSURUTANI, BT GONZALEZ, WD AF TSURUTANI, BT GONZALEZ, WD TI ON THE SOLAR AND INTERPLANETARY CAUSES OF GEOMAGNETIC STORMS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAJOR MAGNETIC STORMS; RING CURRENT; FIELD; WIND; PARTICLES; BOUNDARY; EVENTS; CLOUDS; WAVES AB This article reviews some of the physical properties of geomagnetic storms and the solar and interplanetary causes of these sporadic events. To give the reader an overview of the whole system, the focus will be on the primary plasma processes. References will be provided for those who wish to obtain further information. C1 INST NACL PESQUISAS ESPACIAIS,S JOSE CAMPO,SP,BRAZIL. RP TSURUTANI, BT (reprint author), CALTECH,SPACE PHYS & ASTROPHYS SECT,JET PROPULS LAB,PASADENA,CA 91109, USA. NR 47 TC 12 Z9 12 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUL PY 1993 VL 5 IS 7 BP 2623 EP 2630 DI 10.1063/1.860700 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA LL900 UT WOS:A1993LL90000039 ER PT J AU KRISHER, TP AF KRISHER, TP TI COSMIC BACKGROUND - NO CONFLICT WITH RELATIVITY - REPLY SO PHYSICS TODAY LA English DT Letter ID ONE-WAY SPEED; ISOTROPY; LIGHT RP KRISHER, TP (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 3 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 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD JUL PY 1993 VL 46 IS 7 BP 15 EP 15 PG 1 WC Physics, Multidisciplinary SC Physics GA LN088 UT WOS:A1993LN08800009 ER PT J AU CARLSON, RW TAYLOR, FW AF CARLSON, RW TAYLOR, FW TI THE GALILEO ENCOUNTER WITH VENUS - RESULTS FROM THE NEAR-INFRARED MAPPING SPECTROMETER SO PLANETARY AND SPACE SCIENCE LA English DT Editorial Material ID SIDE C1 UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. RP CARLSON, RW (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 12 TC 11 Z9 12 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 475 EP 476 DI 10.1016/0032-0633(93)90029-2 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900001 ER PT J AU CARLSON, RW KAMP, LW BAINES, KH POLLACK, JB GRINSPOON, DH ENCRENAZ, T DROSSART, P TAYLOR, FW AF CARLSON, RW KAMP, LW BAINES, KH POLLACK, JB GRINSPOON, DH ENCRENAZ, T DROSSART, P TAYLOR, FW TI VARIATIONS IN VENUS CLOUD PARTICLE PROPERTIES - A NEW VIEW OF VENUSS CLOUD MORPHOLOGY AS OBSERVED BY THE GALILEO NEAR-INFRARED MAPPING SPECTROMETER SO PLANETARY AND SPACE SCIENCE LA English DT Article ID NIGHT SIDE AB Using Venus nightside data obtained by the Galileo Near-Infrared Mapping Spectrometer, we have studied the correlation of 1.74 and 2.30 mu m radiation which is transmitted through the clouds. Since the scattering and absorption properties of the cloud particles are different at these two wavelengths, one can distinguish between abundance variations and variations in the properties of the cloud particles themselves. The correlation of intensities shows a clustering of data into five distinct branches. Using radiative transfer calculations, we interpret these branches as regions of distinct but different mixes of Mode 2' and 3 particles. The data and calculations indicate large differences in these modal ratios, the active cloud regions varying in content from nearly pure Mode 2' particles to almost wholly Mode 3. The spatial distribution of these branches shows large scale sizes and both hemispheric symmetries and asymmetries. High-latitude concentrations of large particles are seen in both hemispheres and there is banded structure of small particles seen in both the North and South which may be related. The mean particle size in the Northern Hemisphere is greater than found in the South. If these different branch regions are due to mixing of vertically stratified source regions (e.g. photochemical and condensation source mechanisms), then the mixing must be coherent over very large spatial scales. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV COLORADO,BOULDER,CO 80309. OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. RP CARLSON, RW (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 17 TC 51 Z9 51 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 477 EP 485 DI 10.1016/0032-0633(93)90030-6 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900002 ER PT J AU COLLARD, AD TAYLOR, FW CALCUTT, SB CARLSON, RW KAMP, LW BAINES, KH ENCRENAZ, T DROSSART, P LELLOUCH, E BEZARD, B AF COLLARD, AD TAYLOR, FW CALCUTT, SB CARLSON, RW KAMP, LW BAINES, KH ENCRENAZ, T DROSSART, P LELLOUCH, E BEZARD, B TI LATITUDINAL DISTRIBUTION OF CARBON-MONOXIDE IN THE DEEP ATMOSPHERE OF VENUS SO PLANETARY AND SPACE SCIENCE LA English DT Article ID NIGHT-SIDE; SPECTRA; GALILEO AB A large number of i.r. spectra of Venus was obtained using the Near-Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft, during the February 1990 encounter. Preliminary results show an apparent increase in the tropospheric CO volume mixing ratio (vmr) in the northern polar region: Other; possible explanations of the observations are examined and rejected and an increase of the CO abundance north of 47 degrees N of (35+/-15)% is inferred. Some possible causes of this enhancement are suggested. C1 UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. JET PROP LAB,PASADENA,CA 91109. OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. OI Calcutt, Simon/0000-0002-0102-3170 NR 17 TC 42 Z9 42 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 487 EP 494 DI 10.1016/0032-0633(93)90031-V PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900003 ER PT J AU DROSSART, P BEZARD, B ENCRENAZ, T LELLOUCH, E ROOS, M TAYLOR, FW COLLARD, AD CALCUTT, SB POLLACK, J GRINSPOON, DH CARLSON, RW BAINES, KH KAMP, LW AF DROSSART, P BEZARD, B ENCRENAZ, T LELLOUCH, E ROOS, M TAYLOR, FW COLLARD, AD CALCUTT, SB POLLACK, J GRINSPOON, DH CARLSON, RW BAINES, KH KAMP, LW TI SEARCH FOR SPATIAL VARIATIONS OF THE H2O ABUNDANCE IN THE LOWER ATMOSPHERE OF VENUS FROM NIMS-GALILEO SO PLANETARY AND SPACE SCIENCE LA English DT Article ID NIGHT-SIDE; DARK SIDE; SPECTRA; WATER; EMISSION; AIRGLOW AB The spectroscopic data of the Near-Infrared Mapping Spectrometer (NIMS), recorded during the Galileo flyby of Venus, are analysed to retrieve the water vapour abundance variations in the lower atmosphere of Venus at night. The 1.18 mu m spectral window, which probes altitude levels below 20 km, is used for this purpose. Constraints on the CO2 continuum and far-wing opacity from existing ground-based high-resolution observations are included in the modelling of the NIMS spectra. The NIMS measurements can be fitted with a water vapour mixing ratio of 30+/-15 ppm, in agreement with analyses of ground-based nightside observations. The water vapour abundance shows no horizontal variations exceeding 20% over a wide latitude range (40 degrees S, 50 degrees N) on the nightside of Venus. Within the same selection of NIMS spectra, a large enhancement in the O-2 fluorescence emission at 1.27 mu m is observed at a latitude of 40 degrees S, over a spatial area about 100 km wide. C1 UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV COLORADO,BOULDER,CO 80309. JET PROP LAB,PASADENA,CA 91109. RP DROSSART, P (reprint author), OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. OI Calcutt, Simon/0000-0002-0102-3170 NR 27 TC 47 Z9 48 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 495 EP 504 DI 10.1016/0032-0633(93)90032-W PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900004 ER PT J AU ROOS, M DROSSART, P ENCRENAZ, T LELLOUCH, E BEZARD, B CARLSON, RW BAINES, KH KAMP, LW TAYLOR, FW COLLARD, AD CALCUTT, SB POLLACK, JB GRINSPOON, DH AF ROOS, M DROSSART, P ENCRENAZ, T LELLOUCH, E BEZARD, B CARLSON, RW BAINES, KH KAMP, LW TAYLOR, FW COLLARD, AD CALCUTT, SB POLLACK, JB GRINSPOON, DH TI THE UPPER CLOUDS OF VENUS - DETERMINATION OF THE SCALE HEIGHT FROM NIMS-GALILEO INFRARED DATA SO PLANETARY AND SPACE SCIENCE LA English DT Article AB The 3-5 mu m thermal emission of the nightside of Venus, recorded by the NIMS instrument at the time of the Galileo flyby of Venus, is analysed to infer the properties of the upper cloud boundary. From the global maps of Venus at fixed wavelengths, the limb darkening of the flux is measured at several latitudes, within each infrared channel. By using the nominal Pioneer Venus thermal profile, these data give access to two parameters the cloud deck temperature and the cloud scale height. It is verified independently, from the NIMS spectra, that this thermal profile is consistent with all the NIMS observations, and that the thermal structure does not vary significantly in the latitude range (25 degrees S, 30 degrees N). Within this range, the cloud scale height is found to be constant with latitude, and is is H=5.2 km, with an accuracy of about 15%, taking into account the various sources of theoretical and observational uncertainties. At higher latitudes, the temperature profile becomes more isothermal and the presented method to retrieve His no longer valid. C1 OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. JET PROP LAB,PASADENA,CA 91109. UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV COLORADO,BOULDER,CO 80309. OI Calcutt, Simon/0000-0002-0102-3170 NR 19 TC 20 Z9 20 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 505 EP & DI 10.1016/0032-0633(93)90033-X PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900005 ER PT J AU GRINSPOON, DH POLLACK, JB SITTON, BR CARLSON, RW KAMP, LW BAINES, KH ENCRENAZ, T TAYLOR, FW AF GRINSPOON, DH POLLACK, JB SITTON, BR CARLSON, RW KAMP, LW BAINES, KH ENCRENAZ, T TAYLOR, FW TI PROBING VENUS CLOUD STRUCTURE WITH GALILEO NIMS SO PLANETARY AND SPACE SCIENCE LA English DT Article ID LABORATORY MEASUREMENTS; MIDDLE ATMOSPHERE; DARK SIDE; SPECTROSCOPY; SPECTRUM AB The spectral image cubes obtained by the Near-Infrared Mapping Spectrometer (NIMS) on Galileo as it flew by Venus have been analyzed to constrain the vertical structure of the clouds, the nature of the aerosol particles, and the location and particle properties of the opacity variations responsible for high-contrast features observed in the near-infrared windows at 1.7 and 2.3 mu m. A radiative transfer program was used to simulate mid-latitude curves of limb darkening at 3.7 mu m. Best-fit models to these curves demonstrate that the upper clouds are dominated by mode 2 particles (($) over bar r=1.0 mu m), with a contribution of approximate to 15% of opacity from mode 1 particles (($) over bar r=0.3 mu m). The low-latitude upper cloud is well represented by a dual scale-height model, with a particle scale height of approximate to 1 km from an altitude of 61-63 km, and a scale height of approximate to 6 km above this, up to the level where tau=1 at approximately 71 km. This model also successfully simulates limb-darkening curves at 11.5 Can from the Pioneer Venus Orbiter Infrared Radiometer. Successful simulations of correlation plots of 1.7 vs 2.3 mu m intensities reveal that mode 3 particles (($) over bar r=3.65 mu m) represent the dominant source of opacity in the lower and middle clouds, and that variation in total cloud opacity reflects chiefly the addition and removal of mode 3 particles near the cloud base. We find that the full spectrum of brightnesses at 1.7 and 2.3 mu m implies that the total cloud optical depth varies from approximate to 25 to approximate to 40. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. JET PROP LAB,PASADENA,CA 91109. OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. RP GRINSPOON, DH (reprint author), UNIV COLORADO,LASP,BOULDER,CO 80309, USA. NR 29 TC 67 Z9 69 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 515 EP 542 DI 10.1016/0032-0633(93)90034-Y PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900006 ER PT J AU DROSSART, P ROSENQVIST, J ENCRENAZ, T LELLOUCH, E CARLSON, RW BAINES, KH WEISSMAN, PR SMYTHE, WD KAMP, LW TAYLOR, FW COLLARD, AD CALCUTT, SB THOMPSON, R AF DROSSART, P ROSENQVIST, J ENCRENAZ, T LELLOUCH, E CARLSON, RW BAINES, KH WEISSMAN, PR SMYTHE, WD KAMP, LW TAYLOR, FW COLLARD, AD CALCUTT, SB THOMPSON, R TI EARTH GLOBAL MOSAIC OBSERVATIONS WITH NIMS-GALILEO SO PLANETARY AND SPACE SCIENCE LA English DT Article ID MARTIAN ATMOSPHERE; ISM EXPERIMENT AB During the Earth-1 Galileo flyby (December 1990), the Near-Infrared Mapping Spectrometer (NIMS) experiment investigated the illuminated side of the Earth in the spectral range 0.7-5.2 mu m. Mosaics of the entire terrestrial globe were recorded with a spatial resolution ranging from 100 to 500 km. From these spectra, information is retrieved upon the large-scale temperature structure in the stratosphere and in the mesosphere (0-70 km altitude range) from the inversion of the CO2 bands at 4.3 and 4.8 mu m. These data also permit monitoring of the cloud temperatures, and derivation of the abundances of several minor atmospheric constituents (H2O, CO, N2O, CH4 and O-3). These observations constitute a continuation of the study of the atmospheres of the three planets (i.e. Venus, the Earth and Jupiter) targeted by the Galileo spacecraft during its mission. Observing these atmospheres with the NIMS instrument in the near-infrared will provide a unique data set, useful for comparative planetary studies. C1 JET PROP LAB,PASADENA,CA 91109. UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,OXON,ENGLAND. CORNELL UNIV,PLANETARY STUDIES LAB,ITHACA,NY 14853. RP DROSSART, P (reprint author), OBSERV PARIS,DESPA,CNRS,URA 264,F-92195 MEUDON,FRANCE. OI Calcutt, Simon/0000-0002-0102-3170 NR 15 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUL PY 1993 VL 41 IS 7 BP 551 EP 561 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA MM929 UT WOS:A1993MM92900008 ER PT J AU JOYCE, JE MARTIN, RM THROWER, FP AF JOYCE, JE MARTIN, RM THROWER, FP TI SUCCESSFUL MATURATION AND SPAWNING OF CAPTIVE CHINOOK SALMON BROOD STOCK SO PROGRESSIVE FISH-CULTURIST LA English DT Note ID GAIRDNERI RICHARDSON; ONCORHYNCHUS; TROUT AB Brood stock of chinook salmon (Oncorhynchus tshawytscha) cultured from egg to maturity had low prespawning mortality and highly viable offspring when fed a formulated brood diet and matured in a seawater net-pen with a surface freshwater lens. The brood fish were cultured in freshwater raceways as fry, reared in seawater net-pens from the juvenile (4.7 g) stage until 2 months before spawning, and then transferred into the seawater net-pen modified with a 1-m-thick freshwater lens. Diet was changed 12 months before spawning from a basic formulated commercial diet to a commercial brood-fish diet. The average egg viability to the eyed stage (72% for the progeny of nine females, each crossed with a single male) compared favorably with that of anadromous fish produced at the same facility. Although cultured fish matured younger and smaller, and thus produced smaller eggs and fry, than did wild or anadromous fish of the same stock, juvenile size did not differ after 6 months of freshwater rearing. RP JOYCE, JE (reprint author), NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0033-0779 J9 PROG FISH CULT JI Progress. Fish-Cult. PD JUL PY 1993 VL 55 IS 3 BP 191 EP 194 DI 10.1577/1548-8640(1993)055<0191:SMASOC>2.3.CO;2 PG 4 WC Fisheries SC Fisheries GA MA517 UT WOS:A1993MA51700010 ER PT J AU YUEH, SH KWOK, R AF YUEH, SH KWOK, R TI ELECTROMAGNETIC FLUCTUATIONS FOR ANISOTROPIC MEDIA AND THE GENERALIZED KIRCHHOFF LAW SO RADIO SCIENCE LA English DT Article ID SURFACES AB In this paper the polarimetric emission parameters for anisotropic media are derived using the generalized Kirchhoff's law for media with a uniform temperature and the fluctuation-dissipation theory for media with a temperature profile. Both finite-size objects and half-space media are considered. When the object has a uniform temperature across its body, the Kirchhoff's law, based on the condition of energy conservation in thermal equilibrium is generalized to obtain the emission parameters of an anisotropic medium, which can be interpreted as the absorptivity or the absorption cross section of the complementary object with a permittivity that is the transpose of the original object. When the medium has a nonuniform temperature distribution, the fluctuation-dissipation theory is applied for deriving the covariances between vector components of the thermal currents and, consequently, the covariances of the polarizations of electric fields radiated by the thermal currents. To verify the formulas derived from the fluctuation-dissipation theory, we let the temperature of the object be a constant and show that the results reduce to those obtained from the generalized Kirchhoff's law. RP YUEH, SH (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 13 TC 15 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1993 VL 28 IS 4 BP 471 EP 480 DI 10.1029/93RS01078 PG 10 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA LR260 UT WOS:A1993LR26000003 ER PT J AU BERNHARDT, PA HUBA, JD CHATURVEDI, PK FULFORD, JA FORSYTH, PA ANDERSON, DN ZALESAK, ST AF BERNHARDT, PA HUBA, JD CHATURVEDI, PK FULFORD, JA FORSYTH, PA ANDERSON, DN ZALESAK, ST TI ANALYSIS OF ROCKET BEACON TRANSMISSIONS FOR COMPUTERIZED RECONSTRUCTION OF IONOSPHERIC DENSITIES SO RADIO SCIENCE LA English DT Article ID EQUATORIAL SPREAD-F; TRANSEQUATORIAL BUBBLES; TOMOGRAPHIC INVERSION; SATELLITE PHOTOMETRY; PLASMA DEPLETIONS; EMISSION RATES AB Three methods are described to obtain ionospheric electron densities from transionospheric. rocket-beacon total electron content (TEC) data. First, when the line-of-sight from a ground receiver to the rocket beacon is tangent to the flight trajectory, the electron concentration can be obtained by differentiating the TEC with respect to the distance to the rocket. A similar method may be used to obtain the electron-density profile if the layer is horizontally stratified. Second, TEC data obtained during chemical release experiments may be interpreted with the aid of physical models of the disturbed ionosphere to yield spatial maps of the modified regions. Third, computerized tomography (CT) can be used to analyze TEC data obtained along a chain of ground-based receivers aligned along the plane of the rocket trajectory. CT analysis of TEC data is used to reconstruct a two-dimensional image of a simulated equatorial plume. TEC data is computed for a linear chain of nine receivers with adjacent spacings of either 100 or 200 km. The simulation data are analyzed to provide an F region reconstruction on a grid with 15 x 15 km pixels. Ionospheric rocket tomography may also be applied to rocket-assisted measurements of amplitude and phase scintillations and airglow intensities. C1 UNIV WESTERN ONTARIO,CTR RADIO SCI,LONDON N6A 3K7,ONTARIO,CANADA. USAF,PHILLIPS LAB,DIV IONOSPHER EFFECTS,BEDFORD,MA 01731. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BERNHARDT, PA (reprint author), USN,RES LAB,DIV PLASMA PHYS,SPACE PLASMA BRANCH,WASHINGTON,DC 20375, USA. NR 43 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1993 VL 28 IS 4 BP 613 EP 627 DI 10.1029/93RS00383 PG 15 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA LR260 UT WOS:A1993LR26000016 ER PT J AU SRIVASTAVA, SK JONG, G LEIFER, S SAUNDERS, W AF SRIVASTAVA, SK JONG, G LEIFER, S SAUNDERS, W TI IONIZATION OF C-60 (BUCKMINSTERFULLERENE) BY ELECTRON-IMPACT SO RAPID COMMUNICATIONS IN MASS SPECTROMETRY LA English DT Article ID FULLERENE IONS; CROSS-SECTIONS; C60; POTENTIALS; ENERGY; FOLLENE-60; CLUSTERS; ABINITIO; CARBON; GAS AB Utilizing a crossed electron-beam/molecular-beam collision geometry, mass spectra of C60 and C70 ions have been obtained for an electron impact energy range of 20 eV to 600 eV. These spectra are dominated by singly and doubly ionized species. The intensity of fragment ions is very weak, which is in agreement with previous observations. Ionization efficiency curves for the formation of C60+ and C60(2+) have also been obtained near their threshold regions. From these curves, appearance energies (AE) of these ions have been derived. The AE for C60+ is found to be 7.8+/-0.3 eV, which agrees well with previous measurements. However, our value of 16.4+/-0.3 eV for the formation of C60(2+) is much lower than the value of 19.0+/-0.03 eV obtained by photo-ionization techniques. RP SRIVASTAVA, SK (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 32 TC 9 Z9 9 U1 1 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0951-4198 J9 RAPID COMMUN MASS SP JI Rapid Commun. Mass Spectrom. PD JUL PY 1993 VL 7 IS 7 BP 610 EP 613 DI 10.1002/rcm.1290070711 PG 4 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA LN526 UT WOS:A1993LN52600010 ER PT J AU KIMES, DS KERBER, AG SELLERS, PJ AF KIMES, DS KERBER, AG SELLERS, PJ TI SPATIAL AVERAGING ERRORS IN CREATING HEMISPHERICAL REFLECTANCE (ALBEDO) MAPS FROM DIRECTIONAL REFLECTANCE DATA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SIMPLE BIOSPHERE MODEL; SEMI-ARID REGIONS; AMAZONIAN FOREST; SURFACE ALBEDO; CIRCULATION; RADIANCE; SYSTEM; NADIR; EOS AB The problems in moving from a radiance measurement made for a particular sun-target-sensor geometry to an accurate estimate of the hemispherical reflectance are considerable. A knowledge-based system called VEG was used in this study to infer hemispherical reflectance. Given directional reflectance(s) and the sun angle, VEG selects the most suitable inference technique(s) and estimates the surface hemispherical reflectance with an estimate of the error. Ideally, VEG is applied to homogeneous vegetation. However, what is typically done in GCM (global circulation model) models and related studies is to obtain an average hemispherical reflectance on a square grid cell on the order of 200 km x 200 km. All available directional data for a given cell are averaged (for each view direction), and then a particular technique for inferring hemispherical reflectance is applied to this averaged data. Any given grid cell can contain several surface types that directionally scatter radiation very differently. When averaging over a set of view angles, the resulting mean values may be atypical of the actual surface types that occur on the ground, and the resulting inferred hemispherical reflectance can be in error. These errors were explored by creating a simulated scene and applying VEG to estimate the area-averaged hemispherical reflectance using various sampling procedures. The reduction in the hemispherical reflectance errors provided by using VEG ranged from a factor of 2-4, depending on conditions. This improvement represents a shift from the calculation of a hemispherical reflectance product of relative value (errors of 20% or more), to a product that could be used quantitatively in global modeling applications, where the requirement is for errors to be limited to around 5-10%. The results suggest sampling and averaging strategies for creating hemispherical reflectance maps for photosynthetic, carbon cycle, and climate change studies. RP KIMES, DS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. NR 30 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUL PY 1993 VL 45 IS 1 BP 85 EP 94 DI 10.1016/0034-4257(93)90084-B PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LF966 UT WOS:A1993LF96600008 ER PT J AU MARTUS, KE ORIENT, OJ CHUTJIAN, A AF MARTUS, KE ORIENT, OJ CHUTJIAN, A TI EFFECT OF TRAPPED IONS IN A GATED TIME-OF-FLIGHT APPARATUS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ELECTRON-IMPACT IONIZATION; SQUARE-WAVE GENERATOR; HIGH-VOLTAGE; SPECTROMETER; REFLECTRON AB A three-mesh gate is used in a time-of-flight (TOF) apparatus to analyze the velocity of Positive ions. Test results and a theoretical description are presented of an effect arising from traPPing ions between meshes of a two-gate TOF velocity analyzer. The entrapped ions produce a side peak in the TOF-spectra corresponding to faster ions. The onset and relative height of the side peak is dependent on the gating voltage and risetime of the pulsing electronics, while the relative intensity depends upon the velocity being sampled and the ratio of the gate width to duration. RP MARTUS, KE (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 1993 VL 64 IS 7 BP 1754 EP 1757 DI 10.1063/1.1144005 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA LN411 UT WOS:A1993LN41100011 ER PT J AU RICCITIELLO, SR LOVE, WL PITTS, WC AF RICCITIELLO, SR LOVE, WL PITTS, WC TI A CERAMIC-MATRIX COMPOSITE THERMAL PROTECTION SYSTEM FOR HYPERSONIC VEHICLES SO SAMPE QUARTERLY-SOCIETY FOR THE ADVANCEMENT OF MATERIAL AND PROCESS ENGINEERING LA English DT Article AB The next generation of hypersonic vehicles (NASP, SSTO) that require reusable thermal protection systems will experience acreage surface temperatures in excess of 1100-degrees-C More important, they will experience a more severe physical environment than the Space Shuttle due to non-pristine launching and landing conditions. As a result, maintenance, inspection, and replacement factors must be more thoroughly incorporated into the design of the TPS. To meet these requirements, an advanced thermal protection system was conceived, designated ''TOPHAT '' This system consists of a toughened outer ceramic matrix composite (CMC) attached to a rigid reusable surface insulator (RSI) which is directly bonded to the surface. The objective of this effort was to evaluate this concept in an aeroconvective environment, to determine the effect of impacts to the CMC material, and to compare the results with existing thermal protection systems. C1 ELORET INST,SUNNYVALE,CA. RP RICCITIELLO, SR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 10 TC 0 Z9 0 U1 1 U2 5 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0036-0821 J9 SAMPE QUART PD JUL PY 1993 VL 24 IS 4 BP 10 EP 17 PG 8 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA LQ558 UT WOS:A1993LQ55800002 ER PT J AU BEAM, RM WARMING, RF AF BEAM, RM WARMING, RF TI THE ASYMPTOTIC SPECTRA OF BANDED TOEPLITZ AND QUASI-TOEPLITZ MATRICES SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE TOEPLITZ MATRICES; EIGENVALUES; SPECTRUM; STABILITY AB Toeplitz matrices occur in many mathematical as well as scientific and engineering investigations. This paper considers the spectra of banded Toeplitz and quasi-Toeplitz matrices with emphasis on nonnormal matrices of arbitrarily large order and relatively small bandwidth. These are the type of matrices that appear in the investigation of stability and convergence, of difference approximations to partial differential equations. Quasi-Toeplitz matrices are the result of non-Dirichlet boundary conditions for the difference approximations. The eigenvalue problem for a banded Toeplitz or quasi-Toeplitz matrix of large order is, in general, analytically intractable and (for nonnormal matrices) numerically unreliable. An asymptotic (matrix order tends to infinity) approach partitions the (asymptotic) spectrum of a quasi-Toeplitz matrix into two parts; namely, the analysis for the boundary condition independent spectrum and the analysis for the boundary condition dependent spectrum. The boundary condition independent spectrum is the same as the pure Toeplitz matrix spectrum. Algorithms for computing both parts of the asymptotic spectrum are presented. Examples are used to demonstrate the utility of the algorithms, to present some interesting spectra, and to point out some of the numerical difficulties encountered when conventional matrix eigenvalue routines are employed for nonnormal matrices of large order. The analysis for the Toeplitz spectrum also leads to a diagonal similarity transformation that improves conventional numerical eigenvalue computations. Finally, the algorithm for the asymptotic spectrum is extended to the Toeplitz generalized eigenvalue problem which occurs, for example, in the stability analysis of Pade type difference approximations to differential equations. RP BEAM, RM (reprint author), NASA,AMES RES CTR,COMPUTAT FLUID DYNAM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 16 TC 30 Z9 31 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD JUL PY 1993 VL 14 IS 4 BP 971 EP 1006 DI 10.1137/0914059 PG 36 WC Mathematics, Applied SC Mathematics GA LJ448 UT WOS:A1993LJ44800012 ER PT J AU CHAPMAN, BM MEHROTRA, P ZIMA, HP AF CHAPMAN, BM MEHROTRA, P ZIMA, HP TI HIGH-PERFORMANCE FORTRAN WITHOUT TEMPLATES - AN ALTERNATIVE MODEL FOR DISTRIBUTION AND ALIGNMENT SO SIGPLAN NOTICES LA English DT Article AB Language extensions of Fortran are being developed which permit the user to map data structures to the individual processors of distributed memory machines. These languages allow a programming style in which global data references are used. Current efforts are focussed on designing a common basis for such languages, the result of which is known as High Performance Fortran (HPF). One of the central debates in the HPF effort revolves around the concept of templates, introduced as an abstract index space to which data could be aligned. In this paper, we present a model for the mapping of data which provides the functionality of High Performance Fortran distributions without the use of templates. C1 UNIV VIENNA, DEPT SOFTWARE TECHNOL & PARALLEL SYST, A-1010 VIENNA, AUSTRIA. NASA, LANGLEY RES CTR, ICASE, HAMPTON, VA 23681 USA. NR 14 TC 3 Z9 3 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0362-1340 J9 SIGPLAN NOTICES JI Sigplan Not. PD JUL PY 1993 VL 28 IS 7 BP 92 EP 101 PG 10 WC Computer Science, Software Engineering SC Computer Science GA LF548 UT WOS:A1993LF54800011 ER PT J AU CHATTERJEE, S GILBERT, JR LONG, FJE SCHREIBER, R TENG, SH AF CHATTERJEE, S GILBERT, JR LONG, FJE SCHREIBER, R TENG, SH TI GENERATING LOCAL ADDRESSES AND COMMUNICATION SETS FOR DATA-PARALLEL PROGRAMS SO SIGPLAN NOTICES LA English DT Article; Proceedings Paper CT 4TH SYMP ON PRINCIPLES AND PRACTICE OF PARALLEL PROGRAMMING ( PPOPP ) CY MAY 19-22, 1993 CL SAN DIEGO, CA SP ASSOC COMP MACHINERY, SPECIAL INTEREST GRP PROGRAMMING LANGUAGES AB Generating local addresses and communication sets is an important issue in distributed-memory implementations of data-parallel languages such as High Performance Fortran. We show that for an array A affinely aligned to a template that is distributed across p processors with a cyclic(k) distribution, and a computation involving the regular section A(l: h: s), the local memory access sequence for any processor is characterized by a finite state machine of at most k states. We present fast algorithms for computing the essential information about these state machines, and extend the framework to handle multidimensional arrays. We also show how to generate communication sets using the state machine approach. Performance results show that this solution requires very little runtime overhead and acceptable preprocessing time. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. XEROX CORP,PALO ALTO RES CTR,PALO ALTO,CA 94304. UNIV CALIF SANTA CRUZ,DEPT COMP & INFORMAT SCI,SANTA CRUZ,CA 95064. MIT,DEPT MATH,CAMBRIDGE,MA 02139. NR 10 TC 1 Z9 1 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0362-1340 J9 SIGPLAN NOTICES JI Sigplan Not. PD JUL PY 1993 VL 28 IS 7 BP 149 EP 158 PG 10 WC Computer Science, Software Engineering SC Computer Science GA LF548 UT WOS:A1993LF54800017 ER PT J AU SMITH, GR LEBLANC, M GEISLER, E MCCLANAHAN, S AF SMITH, GR LEBLANC, M GEISLER, E MCCLANAHAN, S TI THE DISTRIBUTED EARTH MODEL ORBITER SIMULATION (DEMOS) 3-DIMENSIONAL SYSTEM AT JOHNSON-SPACE-CENTER SO SIMULATION LA English DT Article DE CELESTIAL MECHANICS; SPACECRAFT ATTITUDE; EIGEN-AXIS MANEUVERS; 3-DIMENSIONAL GRAPHICS; X WINDOW USER INTERFACE AB Filter controllers at the NASA Mission Control Center in Houston have a new visualization tool to help them support the nation's space program. The Distributed Earth Model Orbiter Simulation (DEMOS) system provides three dimensional realistic images of the shuttle as it orbits the Earth. The system displays the correct position and attitude of the supercraft over the Earth's surface. DEMOS also models the locations of the sun, the moon, the planets and the stars. Telemetry supplies the joint angles for the robot arm. Mission Flight controllers can monitor deployment of payloads when there is no live video. DEMOS provides a flexible mission analysis and real time support tool. It unifies the disciplines of celestial mechanics, three dimensional graphics and user interfaces. The paper describes the coordinate systems, the state vector propagation methods and the Attitude Maneuver Predictor (AMP) capabilities. The Attitude Maneuver Predictor simulates eigen-axis maneuver. Flight controllers use this mode often for analysis of thermal constraints on payloads and on the orbiter. C1 NASA,JOHNSON SPACE CTR,MISSION OPERAT DIRECTORATE,HOUSTON,TX 77058. LORAL SPACE INFORMAT SYST,HOUSTON,TX 77058. RP SMITH, GR (reprint author), IBM FED SYST CO,HOUSTON,TX 77058, USA. NR 14 TC 1 Z9 1 U1 1 U2 1 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD JUL PY 1993 VL 61 IS 1 BP 7 EP 21 DI 10.1177/003754979306100102 PG 15 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA MX102 UT WOS:A1993MX10200002 ER PT J AU YAE, KH LIN, TC CHERN, ST FRISCH, HP AF YAE, KH LIN, TC CHERN, ST FRISCH, HP TI OPERATOR-IN-THE-LOOP SIMULATION OF A REDUNDANT MANIPULATOR UNDER TELEOPERATION SO SIMULATION LA English DT Article DE TELEOPERATION; REDUNDANT MANIPULATOR; SIMULATION RECURSIVE DYNAMICS; CONSTRAIN JACOBIAN ID SYSTEM DYNAMIC SIMULATION; RECURSIVE FORMULATION AB For an interactive simulation of 7 degree-of-freedom redundant manipulator under teleoperation, this paper describes an iterative form of resolved-motion rate control in which the constraint Jacobian is constructed on-line in real time and used in the pseudoinverse method as the manipulator's is teleoperated. The manipulator's tasks may involve trajectory following in free space and frequent contact with the environment through pick-and-put operation. The operator's command is interpreted as a series of increments in Cartesian space, and then the constraint Jacobian is developed between two successive increments by viewing the predecessor as the initial configuration and the successor as the target configuration. The pseudoinverse of the constraint Jacobian then generates necessary changes in joint variables and subsequently joint torque. The Jacobian constructed in this way enables us to treat both free motion and environmental contact in the same way. The simulator is built on a two-processor IRIS workstation, with one processor for graphics and the other for dynamics and control analysis. The simulator has a potential for training the teleoperator, developing operational scenarios through visualization of the simulation, and testing the design of operator-machine interface. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP YAE, KH (reprint author), UNIV IOWA,DEPT MECH ENGN,IOWA CITY,IA 52242, USA. NR 28 TC 1 Z9 1 U1 0 U2 0 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD JUL PY 1993 VL 61 IS 1 BP 40 EP 50 DI 10.1177/003754979306100104 PG 11 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA MX102 UT WOS:A1993MX10200004 ER PT J AU DENNIS, BR ZARRO, DM AF DENNIS, BR ZARRO, DM TI THE NEUPERT EFFECT - WHAT CAN IT TELL US ABOUT THE IMPULSIVE AND GRADUAL PHASES OF SOLAR-FLARES SO SOLAR PHYSICS LA English DT Article ID X-RAY OBSERVATIONS; ELECTRONS; BURSTS; MODEL AB The Neupert effect is the name given to the correlation observed in many flares between the time-integrated microwave and hard X-ray emissions and the soft X-ray emission light curve. We have used hard X-ray data from the Hard X-Ray Burst Spectrometer (HXRBS) on the Solar Maximum Mission (SMM) and soft X-ray data from the detector on GOES to determine what fraction of all events show this correlation and how the correlation changes from the impulsive to the gradual phase. We have found that of 66 HXRBS events observed in 1980 with a peak rate of > 1000 counts s-1, 58 (80%) showed good correlations with peaks in the GOES time derivative plot corresponding to peaks in the hard X-ray (HXR) plots to within +/- 20 s. In 20 of these good-correlation cases (30%), the soft X-ray (SXR) time derivative stays high after the HXR emission has decreased suggesting that the later emissions result from energy release in a loop already affected by the initial energy release. In 8 of the 13 flares that showed poor correlation, the SXR time derivative shows no peak corresponding to the initial HXR impulsive peak that has structure on a time scale of less-than-or-equal-to 1 s. This suggests that in these events the initial impulsive energy release results primarily in electron acceleration, and that the secondary plasma heating from the accelerated electrons contributes relatively little compared to the more gradual plasma heating already taking place at the same time. The more gradually varying events, commonly referred to as type C flares, tend to show poorer correlation between the SXR time derivative and the HXR time profile. Of 26 GOES X1 or greater flares recorded between 1980 and 1989 with HXR peaks lasting over 10 min, 13 (50%) showed poor correlation with the gradual HXR peaks either not registering at all in the SXR time derivative plots or showing up as very broad peaks. In one case, on 1981 April 26, the SXR time derivative peak was delayed by 13 min. Only 17 (65%) of the 26 X-flares had an earlier, impulsive component and of those, 12 (71%) showed good correlation between the impulsive peaks. C1 NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,GREENBELT,MD 20771. RP DENNIS, BR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Dennis, Brian/C-9511-2012 NR 30 TC 201 Z9 202 U1 0 U2 0 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 1993 VL 146 IS 1 BP 177 EP 190 DI 10.1007/BF00662178 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG620 UT WOS:A1993LG62000014 ER PT J AU HUBBARD, GS WERCINSKI, PF SARVER, GL HANEL, RP RAMOS, R AF HUBBARD, GS WERCINSKI, PF SARVER, GL HANEL, RP RAMOS, R TI A MARS ENVIRONMENTAL SURVEY (MESUR) - FEASIBILITY OF A LOW-COST GLOBAL APPROACH SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB In situ measurements of Mars' surface and atmosphere are the objectives of a novel network mission concept called the Mars Environmental SURvey (MESUR). As envisioned, the MESUR (pronounced ''measure'') mission will emplace a pole-to-pole global distribution of 16 landers on the martian surface over three launch opportunities using medium-lift (Delta-class) launch vehicles. Our basic concept is to deploy small free-flying probes which would directly enter the Mars atmosphere, measure the upper atmospheric structure, image the local terrain before landing, and survive landing to perform meteorology, seismology, surface imaging, and soil chemistry measurements. Data will be returned via dedicated relay orbiter or direct-to-Earth transmission. The mission philosophy is to (a) ''grow'' a network over a period of years using a series of launch opportunities, thereby minimizing the peak annual costs; (b) develop a level-of-effort which is flexible and responsive to a broad set of objectives; (c) focus on Mars science while providing a solid basis for future human presence; and (d) minimize overall project cost and complexity wherever possible. RP HUBBARD, GS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD JUL PY 1993 VL 13 IS 4 BP 363 EP 370 PG 8 WC Engineering, Aerospace SC Engineering GA LK612 UT WOS:A1993LK61200001 ER PT J AU MAHONEY, MJ AF MAHONEY, MJ TI 4 NASA SUBMILLIMETER-WAVELENGTH SPACE-ASTROPHYSICS MISSIONS SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB Beginning in the late 1970s with work on what was to become known as the Large Deployable Reflector (LDR), studies have been conducted at the NASA/Jet Propulsion Laboratory on several submillimeter-wavelength, space observatories. These observatories will explore the largely unknown far-infrared- and submillimeter-wavelength spectrum, and are expected to help astronomers understand many new and exciting aspects of the universe that we live in. Combined with work elsewhere, there is now defined a sequence of submillimeter missions which first perform exploratory spectral line observations, then a complete spectral line survey, and ultimately high-resolution imaging. Two possible options for a submillimeter survey mission are discussed in this paper: the Submillimeter Explorer (SMME) and the Submillimeter Imager and Line Survey (SMILS). A third option, the Submillimeter Intermediate Mission (SMIM), is currently under study. It lies between SMME and SMILS in its observational capability and would perform a high-spectral-resolution survey of several hundred sources at wavelengths between 100 and almost-equal-to 750 mum with modest angular resolution (< 10''). Following a survey mission, the LDR and/or the Synthesis Array for Lunar Submillimeter Astronomy (SALSA) would be flown. LDR is a 10-20-m dia telescope with greatly increased sensitivity and imaging capabilities compared to the earlier missions. SALSA, on the other hand, is a moon-based array consisting of twelve, 3.5-m dia telescopes with a maximum baseline of nearly 1 km. With operating wavelengths between 30 and 500 mum, SA LSA would achieve 10 milli-arcsecond angular resolution, and thus could explore source structure in much greater detail than the other missions. The purpose of this paper is to present the status of the conceptual designs for these missions. RP MAHONEY, MJ (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD JUL PY 1993 VL 13 IS 4 BP 371 EP 381 PG 11 WC Engineering, Aerospace SC Engineering GA LK612 UT WOS:A1993LK61200002 ER PT J AU MENDELL, WW AF MENDELL, WW TI A MISSION DESIGN FOR INTERNATIONAL MANNED MARS MISSION - [FROM THE 1991 INTERNATIONAL-SPACE-UNIVERSITY (ISU) DESIGN PROJECT] SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB The International Space University (ISU) conducted a study of an international program to support human exploration of Mars as its annual Design Project activity during its 1991 summer session in Toulouse, France. Although an ISU Design Project strives to produce an in-depth analysis during the intense 10-week summer session, the International Mars Mission (IMM) project was conducted in a manner designed to provide a learning experience for young professionals working in an unusual multidisciplinary and multinational environment. The breadth of the IMM study exceeds that of most Mars mission studies of the past, encompassing political organization for long-term commitment, multinational management structure, cost analysis, mission architecture, vehicle configuration, crew health, life support, Mars surface infrastructure, mission operations, technology evaluation, risk assessment, scientific planning, exploration, communication networks, and martian resource utilization. The IMM Final Report has particular value for those seeking insight into the choices made by a multinational group working in an apolitical environment on the problems of international cooperation in space. RP MENDELL, WW (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV SOLAR SYST EXPLORAT,ISU91 DESIGN PROJECT,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD JUL PY 1993 VL 13 IS 4 BP 383 EP 394 PG 12 WC Engineering, Aerospace SC Engineering GA LK612 UT WOS:A1993LK61200003 ER PT J AU CHAPPELLAZ, JA FUNG, IY THOMPSON, AM AF CHAPPELLAZ, JA FUNG, IY THOMPSON, AM TI THE ATMOSPHERIC CH4 INCREASE SINCE THE LAST GLACIAL MAXIMUM SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article AB An estimate of the distribution of wetland area and associated CH, emission is presented for the Last Glacial Maximum (LGM, 18 kyr BP, kiloyear Before Present) and the Pre-Industrial Holocene (PIH, 9000-200 years BP). The wetland source, combined with estimates of the other biogenic sources and sink, yields total source strengths of 120 and 180 Tg CH4/yr for LGM and PIH respectively. These source strengths are shown to be consistent with source estimates inferred from a photochemical model, and point to changes in wetland CH4 source as a major factor driving the atmospheric CH4 increase from LGM to PIH. RP CHAPPELLAZ, JA (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Chappellaz, Jerome/A-4872-2011; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 0 TC 110 Z9 112 U1 1 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1993 VL 45 IS 3 BP 228 EP 241 DI 10.1034/j.1600-0889.1993.t01-2-00002.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LP579 UT WOS:A1993LP57900002 ER PT J AU THOMPSON, AM CHAPPELLAZ, JA FUNG, IY KUCSERA, TL AF THOMPSON, AM CHAPPELLAZ, JA FUNG, IY KUCSERA, TL TI THE ATMOSPHERIC CH4 INCREASE SINCE THE LAST GLACIAL MAXIMUM .2. INTERACTIONS WITH OXIDANTS SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article AB Two studies of the effect of changing CH4 fluxes on global tropospheric oxidant levels, O3, OH, H2O2, have been performed with a multi-box photochemical model. (1) A sensitivity study is made by scaling back CH4, CO and NO emissions relative to present-day budgets. When the CH4 ice core record is compared to calculated CH4 abundances, corresponding CH4 fluxes for the pre-industrial Holocene (PIH) and Last Glacial Maximum (LGM) are fairly well-constrained: 175-225 Tg CH4/yr for PIH and 100-130 Tg CH4 /yr for LGM. Except for OH at fluxes of 100-200 Tg CH4/yr, preindustrial oxidant concentrations levels are not narrowly defined by the CH4 record. The small range of CH4 flux and OH abundance at the LGM is due to strong CH4-OH feedbacks. (2) Specific scenarios for CH4/CO/NO are selected to represent sources for the PIH and LGM. The CH, budget is taken from an evaluation of wetlands and other natural sources. For CO and NO, apparent O3 levels and ice-core-derived H2O2 for the PIH are used to constrain PIH CO and NO fluxes. These fluxes are further scaled back to simulate the LGM, and perturbed temperature, precipitation and stratosphere-troposphere exchange are prescribed according to the GISS GCM. For the PIH changes for global abundance relative to present day are: 44% less O3; 20% more OH and 56% less H2O2. For the LGM, with 120 Tg CH4/yr and surface temperature 4-5 K lower than today, global changes are 56 % less O3, 32 % more OH and 59 % less H2O2. Calculated preindustrial oxidant changes are in reasonable agreement with other studies based on one-, two- and three-dimensional models, although differences among model physics preclude a definitive comparison. There is consensus that OH has decreased since the Last Glacial Maximum, in contrast to projections for future OH, on which models are in disagreement. Model validation of oxidant concentrations requires more ice-core data. Preindustrial OH would be inferred best by using a model with ice-core measurements of species that are uncoupled from the CH4-CO-OH-O3 cycle. Candidates might be marine gases of moderately long lifetime, e.g., CH3Cl or OCS. RP THOMPSON, AM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Chappellaz, Jerome/A-4872-2011; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 0 TC 49 Z9 50 U1 0 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1993 VL 45 IS 3 BP 242 EP 257 DI 10.1034/j.1600-0889.1993.t01-2-00003.x PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LP579 UT WOS:A1993LP57900003 ER PT J AU BAUSCHLICHER, CW TAYLOR, PR AF BAUSCHLICHER, CW TAYLOR, PR TI ATOMIC NATURAL ORBITAL BASIS-SETS FOR TRANSITION-METALS SO THEORETICA CHIMICA ACTA LA English DT Article DE NATURAL ORBITALS; ATOMIC NOS; TRANSITION-METAL BASIS SETS ID GAUSSIAN-BASIS SETS; MOLECULAR WAVE-FUNCTIONS; ANO BASIS-SETS; RELATIVISTIC CALCULATIONS; GENERAL CONTRACTION; POSITIVE-IONS; ROW ATOMS; 1ST-ROW AB We show that atomic natural orbitals are an excellent way to contract transition-metal basis sets, even though the different low-lying electronic states may have very different basis set requirements. C1 ELORET INST, PALO ALTO, CA 94303 USA. RP NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 30 TC 39 Z9 39 U1 1 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD JUL PY 1993 VL 86 IS 1-2 BP 13 EP 24 DI 10.1007/BF01113513 PG 12 WC Chemistry, Physical SC Chemistry GA LP788 UT WOS:A1993LP78800003 ER PT J AU DIMOFTE, F AF DIMOFTE, F TI EFFECT OF FLUID COMPRESSIBILITY ON JOURNAL BEARING PERFORMANCE SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT TRIBOLOGY CONF CY OCT 19-21, 1992 CL SAN DIEGO, CA SP AMER SOC MECH ENGINEERS, SOC TRIBOLOGISTS & LUBRICAT ENGINEERS DE BEARINGS; FLUID FILM BEARINGS; HYDRODYNAMIC; COMPRESSIBLE FLUIDS AB An analysis was undertaken to determine the effect of fluid film compressibility on the performance of fluid film bearings. A new version of the Reynolds equation was developed, using a polytropic expansion, for both steady-state and dynamic conditions. Polytropic exponents from 1 (isothermal) to 1000 (approaching an incompressible liquid) were evaluated for two bearing numbers, selected from a range of practical interest for cryogenic application, and without cavitation. Bearing loads were insensitive to fluid compressibility for low bearing numbers, as was expected. The effect of compressibility on attitude angle was significant, even when the bearing number was low. A small amount of fluid compressibility was enough to obtain stable running conditions. Incompressible liquid lacked stability at all conditions. Fluid compressibility can be used to control the bearing dynamic coefficients, thereby influencing the dynamic behavior of the rotor-bearing system. RP DIMOFTE, F (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 14 TC 2 Z9 2 U1 2 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1993 VL 36 IS 3 BP 341 EP 350 DI 10.1080/10402009308983168 PG 10 WC Engineering, Mechanical SC Engineering GA LL446 UT WOS:A1993LL44600002 ER PT J AU MIYOSHI, K HONECY, FS ABEL, PB PEPPER, SV SPALVINS, T WHEELER, DR AF MIYOSHI, K HONECY, FS ABEL, PB PEPPER, SV SPALVINS, T WHEELER, DR TI A VACUUM (10(-9) TORR) FRICTION APPARATUS FOR DETERMINING FRICTION AND ENDURANCE LIFE OF MOSX FILMS SO TRIBOLOGY TRANSACTIONS LA English DT Article ID LUBRICANT FILMS; HERTZIAN STRESS; SURFACES; COATINGS; CONTACT; LAYERS; WEAR AB The first part of this paper describes an ultrahigh vacuum friction apparatus (tribometer). The tribometer can be used in a ball-on-disk configuration and is specifically designed to measure the friction and endurance life of solid lubricating films such as MoS(x) in vacuum at a pressure of 10(-7) Pa, 10(-9) torr. The sliding mode is typically unidirectional at a constant rotating speed. The second part of this paper presents some representative friction and endurance life data for magnetron sputtered MoS(x) films, 110 nm thick, deposited on sputter-cleaned 440C stainless-steel disk substrates, which were slid against a 6-mm-diameter 440C stainless-steel bearing ball. All experiments were conducted with loads of 0.49 to 3.6 N, average Hertzian contact pressure, 0.33 to 0.69 GPa, at a constant rotating speed of 120 rpm, sliding velocity ranging from 31 to 107 mm/s due to the range of wear track radii involved in the experiments, in a vacuum of 7 x 10(-7) Pa, 5 x 10(-9) torr, and at room temperature. The results indicate that there are similarities in friction behavior of MoS(x) films over their life cycles regardless of load applied. The coefficient of friction mu decreases as load W increases according to mu = kW-1/3, which is in agreement with the Hertzian contact model. The endurance life E of MoS(x) films decreases as the load W increases according to E = KW-1.4 for the load range. The load- (contact pressure-) dependent endurance life allows a reduction in the time needed for wear experiments and an acceleration of endurance life testing of MoS(x) films. For the magnetron-sputtered MoS(x) films deposited on 440C stainless-steel disks, the specific wear rate normalized to the load and the number of revolutions was 3 x 10(-8) mm3/N.revolution; the specific wear rate normalized to the load and the total sliding distance was 8 x 10(-7) mm3/N.m; and the nondimensional wear coefficient was approximately 5 x 10(-6). The values are almost independent of load in the range 0.49 to 3.6 N, average Hertzian contact pressure of 0.33 to 0.69 GPa. RP MIYOSHI, K (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 24 TC 10 Z9 10 U1 1 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1993 VL 36 IS 3 BP 351 EP 358 DI 10.1080/10402009308983169 PG 8 WC Engineering, Mechanical SC Engineering GA LL446 UT WOS:A1993LL44600003 ER PT J AU DELLACORTE, C AF DELLACORTE, C TI AN ANALYSIS OF THE WEAR BEHAVIOR OF SIC WHISKER-REINFORCED ALUMINA FROM 25-DEGREES-C TO 1200-DEGREES-C SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT TRIBOLOGY CONF CY OCT 19-21, 1992 CL SAN DIEGO, CA SP AMER SOC MECH ENGINEERS, SOC TRIBOLOGISTS & LUBRICAT ENGINEERS DE CERAMICS; FRICTION; WEAR; HIGH TEMPERATURE ID COMPOSITE; STRESSES; MATRIX AB This Paper describes a model for predicting the wear behavior of whisker-reinforced ceramics. The model has been successfully applied to a silicon carbide whisker-reinforced alumina ceramic composite subjected to sliding contact. The model compares the frictional forces on the whiskers due to sliding, which act to pull or push them out of the matrix, to the clamping or compressive forces on the whiskers due to the matrix, which act to hold the whiskers in the composite. At low temperatures, the whiskers are held strongly in the matrix and are fractured into pieces during the wear process along with the matrix. At elevated temperatures, differential thermal expansion between the whiskers and matrix can cause a loosening of the whiskers and lead to pullout during the wear process and to higher wear. The model, which represents the combination of an elastic stress analysis and a friction heating analysis, predicts a transition temperature at which the strength of the whiskers equals the clamping force holding them in the matrix. Above the transition, the whiskers are pulled out of the matrix during sliding, and below the transition the whiskers are fractured. The existence of the transition gives rise to a dual wear mode or mechanism behavior for this material which has been observed in laboratory experiments. The results from this model correlate well with experimentally observed behavior indicating that the model may be useful in obtaining a better understanding of material behavior and in making material improvements. RP DELLACORTE, C (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 16 TC 2 Z9 2 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1993 VL 36 IS 3 BP 452 EP 460 DI 10.1080/10402009308983183 PG 9 WC Engineering, Mechanical SC Engineering GA LL446 UT WOS:A1993LL44600017 ER PT J AU MOGHADDAM, M CHEW, WC AF MOGHADDAM, M CHEW, WC TI VARIABLE-DENSITY LINEAR ACOUSTIC INVERSE PROBLEM SO ULTRASONIC IMAGING LA English DT Article DE ACOUSTIC TOMOGRAPHY; INVERSE SCATTERING; VARIABLE DENSITY ID DIFFRACTION TOMOGRAPHY; ULTRASONICS C1 UNIV ILLINOIS,DEPT ELECT & COMP ENGN,ELECTROMAGNET LAB,URBANA,IL 61801. RP MOGHADDAM, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Chew, Weng Cho/C-1792-2009 NR 17 TC 8 Z9 8 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0161-7346 J9 ULTRASONIC IMAGING JI Ultrason. Imaging PD JUL PY 1993 VL 15 IS 3 BP 255 EP 266 DI 10.1006/uimg.1993.1016 PG 12 WC Acoustics; Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Acoustics; Engineering; Radiology, Nuclear Medicine & Medical Imaging GA MV103 UT WOS:A1993MV10300005 PM 8879095 ER PT J AU MARTIN, JML TAYLOR, PR AF MARTIN, JML TAYLOR, PR TI THE MECHANISM OF THE REACTION CH+N2-]HCN+N SO CHEMICAL PHYSICS LETTERS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; COUPLED-CLUSTER METHOD; TRIPLE EXCITATIONS; MOLECULAR CALCULATIONS; THEORETICAL TREATMENT; BASIS SETS; SINGLES; TEMPERATURE; CHEMISTRY; ATOMS AB The lowest doublet and quartet reaction surfaces of the title reaction have been studied using complete active space SCF, multireference CI, and augmented coupled cluster (CCSD (T) ) methods. Several additional intermediates and transition states have been found beyond those considered in previous work. It is found that not one but three intersystem crossings are present along one suggested ''reaction coordinate'', which also has a high barrier to reaction. It therefore seems possible that the reaction mechanism is different from what has been previously been suggested. At the highest level of theory, the reaction enthalpy at absolute zero is found to be + 3.1 kcal/mol, in excellent agreement with experiment. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. ELORET INST, PALO ALTO, CA 94303 USA. LIMBURGS UNIV CTR, DEPT SBG, B-3590 DIEPENBEEK, BELGIUM. UNIV INSTELLING ANTWERP, DEPT CHEM, INST MAT SCI, B-2610 WILRIJK, BELGIUM. RI Martin, Jan/A-7457-2008 OI Martin, Jan/0000-0002-0005-5074 NR 34 TC 42 Z9 42 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 25 PY 1993 VL 209 IS 1-2 BP 143 EP 150 DI 10.1016/0009-2614(93)87215-O PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LH246 UT WOS:A1993LH24600024 ER PT J AU RUBINCAM, DP AF RUBINCAM, DP TI THE OBLIQUITY OF MARS AND CLIMATE FRICTION SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SOLAR-SYSTEM; INERTIA; OSCILLATIONS; REGOLITH; MOMENT AB The mean obliquity of Mars may have increased over geologic time due to climatic changes associated with obliquity oscillations; this mechanism is dubbed ''climate friction.'' Given here is the mathematical theory of climate friction. Also, a 10 m.y. numerical integration of the equations for a hypothetically large amount of climate friction is performed, for the cases of the obliquity oscillations being (1) a single sinusoid and (2) a sum of three sinusoids. Theory and numerics agree in both cases within about 12% on the size of the secular increase in obliquity, with most of the discrepancy coming from the theory giving obliquity amplitudes approximately 10% too large. Further, one possible mechanism of climate friction is investigated here: ''postglacial rebound'' on Mars. The idea is that giant polar caps form when the obliquity is low. These caps slowly squeeze out an equatorial bulge. When the obliquity is high, the caps disappear, but the bulge takes some time to collapse, due to mantle viscosity. Thus the equatorial bulge oscillates but is out of phase with the obliquity oscillations. Like tidal friction, this causes a secular increase in the average obliquity. Using the preferred climate model of Francois et al. (1990), the total secular increase in the obliquity over the age of the solar system can amount to about 10-degrees if Mars' mantle has an Earthlike effective viscosity of 3 x 10(21) Pa s (3 x 10(22) P). The secular change is negligible for effective viscosities which differ by more than a factor of 10 from this value. Last, how much climate friction tipped the Earth is presently unknown. RP RUBINCAM, DP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERRESTRIAL PHYS LAB,GEODYNAM BRANCH,CODE 921,GREENBELT,MD 20771, USA. RI Rubincam, David/D-2918-2012 NR 23 TC 16 Z9 16 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10827 EP 10832 DI 10.1029/93JE00999 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600001 ER PT J AU HABERLE, RM AF HABERLE, RM TI INTRODUCTION TO THE MSATT SPECIAL SECTION .2. SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Editorial Material RP HABERLE, RM (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10897 EP 10897 DI 10.1029/93JE01083 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600007 ER PT J AU ZAHNLE, KJ AF ZAHNLE, KJ TI XENOLOGICAL CONSTRAINTS ON THE IMPACT EROSION OF THE EARLY MARTIAN ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID NOBLE-GASES; MASS FRACTIONATION; ASTEROID IMPACTS; CARBON-DIOXIDE; SOLAR-SYSTEM; EARLY MARS; EARTH; EVOLUTION; VOLATILES; CLIMATE AB The roughly uniform hundredfold depletion of observable Martian atmophiles (nonradiogenic noble gases and reconstituted nitrogen) with respect to Earth implies that Mars lost its atmosphere by a relatively efficient, nonfractionating process. Impact erosion (expulsion of atmosphere by impacts) is an appealing candidate. Noble gases can be used to test this hypothesis. Xenon in particular can be used to impose three constraints on how Mars lost its atmosphere: its very low abundance compared to Earth, Venus, and likely meteoritic sources; its distinctive isotopic composition compared to likely meteoritic sources; and the relatively high absolute abundance of radiogenic Xe-129, daughter of the extinct radionuclide I-129 (half-life 17 m.y.). A fourth useful constraint is imposed by radiogenic Ar-40. If produced by impact erosion, the first two constraints become constraints on the composition, mass distribution, and orbital elements of the impactors. The third and fourth constraints imply that Mars lost its nonradiogenic noble gases early, perhaps before it was 100 Myr old. Impact erosion can be invoked to explain Mars by any of three stories: (1) Mars is unlikely. In a sort of planetary brinkmanship, impact erosion almost removed the entire atmosphere but was arrested just in time. (2) Martian noble gases are cometary and cometary Xe is as isotopically mass fractionated as Martian and terrestrial Xe. This is most easily accomplished if a relatively thick geochemically controlled CO2 atmosphere protected trace atmophiles against escape. It is not known if comets actually have the desired composition. (3) Mars was indeed stripped of its early atmosphere but a small remnant was safely stored in the regolith, later released as a by-product of water mobilization. RP ZAHNLE, KJ (reprint author), NASA, AMES RES CTR, MS 2453, MOFFETT FIELD, CA 94035 USA. NR 51 TC 26 Z9 26 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10899 EP 10913 DI 10.1029/92JE02941 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600008 ER PT J AU ANBAR, AD ALLEN, M NAIR, HA AF ANBAR, AD ALLEN, M NAIR, HA TI PHOTODISSOCIATION IN THE ATMOSPHERE OF MARS - IMPACT OF HIGH-RESOLUTION, TEMPERATURE-DEPENDENT CO2 CROSS-SECTION MEASUREMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT WORKSHOP ON MARTIAL SURFACE ATMOSPHERE THROUGH TIME CY SEP 23-25, 1991 CL BOULDER, CO ID MARTIAN ATMOSPHERE; WATER-VAPOR; MOLECULAR-OXYGEN; OZONE DENSITY; ABSORPTION; O-2; O2; PHOTOCHEMISTRY; STABILITY; SCHUMANN AB We have investigated the impact of high resolution temperature-dependent CO2 cross-section measurements (Lewis and Carver, 1983) on calculations of photodissociation rate coefficients in the Martian atmosphere. Since the cross-section measurements exhibit large variations on a 10-20 angstrom scale, the calculations are sensitive to the wavelength resolution. We find that the adoption of 50 angstrom intervals for the purpose of computational efficiency results in errors in the calculated values for photodissociation of CO2, H2O, and O2 which are generally less-than-or-equal-to 10%, but as large as 20% in some instances. These are acceptably small errors, especially considering the uncertainties introduced by the large temperature dependence of the CO2 cross-section. The inclusion of temperature-dependent CO2 cross-sections is shown to lead to a decrease in the diurnally averaged rate of CO2 photodissociation as large as 33% at some altitudes, and increases of as much as 950% and 80% in the photodissociation rate coefficients of H2O and O2 respectively. The actual magnitude of the changes depends on the assumptions used to model the CO2 absorption spectrum at temperatures lower than the available measurements, and at wavelengths longward of 1970 angstrom. Given our current understanding, these results minimize or even reverse the sense of the CO2 chemical stability problem. C1 JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109. RP ANBAR, AD (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. NR 58 TC 24 Z9 24 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10925 EP 10931 DI 10.1029/93JE00330 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600010 ER PT J AU ANBAR, AD LEU, MT NAIR, HA YUNG, YL AF ANBAR, AD LEU, MT NAIR, HA YUNG, YL TI ADSORPTION OF HOX ON AEROSOL SURFACES - IMPLICATIONS FOR THE ATMOSPHERE OF MARS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT WORKSHOP ON MARTIAL SURFACE ATMOSPHERE THROUGH TIME CY SEP 23-25, 1991 CL BOULDER, CO ID MARTIAN ATMOSPHERE; HETEROGENEOUS REACTIONS; WATER-VAPOR; PHOTOCHEMISTRY; STABILITY; CHEMISTRY; ICE; TEMPERATURE; OZONE; STRATOSPHERE AB The potential impact of heterogeneous chemistry on the abundance and distribution of HO(x) in the atmosphere of Mars has been assessed by combining observational data of dust and ice aerosol distributions with an updated photochemical model. Critical parameters include the altitude distributions of aerosols, and the surface loss coefficients (gamma) of HO2 on dust and ice in the lower atmosphere, and H on ice above 40 km. We find that adsorption of HO2 on dust (gamma(HO2) greater-than-or-equal-to 0.01), or ice near 30 km (gamma(HO2) greater-than-or-equal-to 0.1), can deplete OH abundances in the lower atmosphere by 10% or more. Such depletions approach those obtained by lowering the water vapor abundance by an order of magnitude below the global average observed by Viking (almost-equal-to 25%). Since the oxidation of CO is catalyzed by HO(x) in the lower atmosphere via the reaction CO + OH --> CO2 + H, loss of OH due to adsorption of HO2 on dust or ice at low altitudes could have a significant effect on the ratio CO:CO2. The adsorption of H on ice at 50 km (gamma(H) greater-than-or-equal-to 0.01) can result in even larger OH depletions. However, this effect is localized to altitudes > 40 km, where CO oxidation is relatively unimportant. Laboratory data suggest that gamma(HO2) almost-equal-to 0.01 is a reasonable estimate for adsorption on dust. Larger values am plausible, but we not stongly supported by experimental evidence. The reactivity of HO2 on ice is unknown, while gamma(H) on ice appears to be < 0.001. There is a need for measurements of HO(x) adsorption on surfaces representative of Martian aerosols at temperatures < 220 K. C1 JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109. RP ANBAR, AD (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. NR 55 TC 15 Z9 15 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10933 EP 10940 DI 10.1029/93JE00132 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600011 ER PT J AU MARTIN, TZ RICHARDSON, MI AF MARTIN, TZ RICHARDSON, MI TI NEW DUST OPACITY MAPPING FROM VIKING INFRARED THERMAL MAPPER DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT WORKSHOP ON MARTIAL SURFACE ATMOSPHERE THROUGH TIME CY SEP 23-25, 1991 CL BOULDER, CO ID MARTIAN ATMOSPHERE; MARS ATMOSPHERE; STORMS; CIRCULATION; SURFACE; DEVILS AB Global dust opacity mapping for Mars has been carried forward using the approach described by Martin (1986) for Viking IR Thermal Mapper data. New maps are presented for the period from the beginning of Viking observations, until L(s) 210-degrees in 1979 (1.36 Mars years). This range includes the second and more extensive planet-encircling dust storm observed by Viking, known as storm 1977b. Improvements in approach result in greater time resolution and smaller noise than the earlier work. A strong local storm event filled the Hellas basin at L(s) 170-degrees, prior to the 1977a storm. Dust is retained in equatorial regions following the 1977b storm far longer than in mid-latitudes. Minor dust events appear to raise the opacity in northern high latitudes during northern spring. Additional mapping with high time resolution has been done for the periods of time near the major storm origins in order to search for clues to the mechanism of storm initiation. The first evidence of the start of the 1977b storm is pushed back to L(s) 274.2-degrees, preceding signs of the storm in images by about 15 hours. C1 UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON SW7 2AZ,ENGLAND. RP MARTIN, TZ (reprint author), JET PROP LAB,MAIL STOP 19237,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 54 Z9 54 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 10941 EP 10949 DI 10.1029/93JE01044 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600012 ER PT J AU PARKER, TJ GORSLINE, DS SAUNDERS, RS PIERI, DC SCHNEEBERGER, DM AF PARKER, TJ GORSLINE, DS SAUNDERS, RS PIERI, DC SCHNEEBERGER, DM TI COASTAL GEOMORPHOLOGY OF THE MARTIAN NORTHERN PLAINS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT WORKSHOP ON MARTIAL SURFACE ATMOSPHERE THROUGH TIME CY SEP 23-25, 1991 CL BOULDER, CO ID OUTFLOW CHANNELS; MARS; WATER; FEATURES; ICE; EROSION; RELEASE; ORIGIN; EARTH; FLOWS AB The northern lowland plains comprise approximately one third Mars' surface area. Most outflow channels and many valley networks debouch into the lowlands, yet there is little or no morphologic evidence to suggest that channel cutting continued far into the plains, despite a continued basinward regional topographic gradient. The immediate fate of the water discharged from these channels was dependent on the prevailing paleoclimate at the time of its emplacement. Though current models of the martian paleoclimate suggest that mean annual temperatures were likely below freezing throughout most of martian history, geomorphic evidence suggests that coastal erosion on a scale comparable to that of well-known terrestrial paleolakes occurred. These landforms can be traced to nearly complete closure of the northern plains and appear to require at least two, and perhaps several, highstands of a sea or ocean with temperatures above freezing at least for geologically brief periods of time. The latest highstand may have been as recent as Early Amazonian time. The elevations and areal extent of these landforms provide independent estimates of the martian water budget that can be compared to prevailing models of martian volatile evolution. Estimated volumes of water and sediment discharged by the major channel systems peripheral to the northern plains can be compared to the volume of the basin based on the available topography. Values for the circum-Chryse outflow channels alone are sufficient to have produced large bodies of standing water within the basin. These estimates may be comparable to the basin volume contained within the younger, least extensive highstand identified. The earlier, more extensive highstand delineates a basin with a much larger implied volume that may require the presence of a semi-permanent, possibly ice-covered ocean in the northern plains prior to major channeling events. The northern plains today probably consist of water-lain sediments interbedded to considerable depths with flood lavas from the major volcanic centers, with sediment comprising most of the present surface. C1 JET PROP LAB,PASADENA,CA 91109. MARK GRP,SANTA ANA,CA 92705. RP PARKER, TJ (reprint author), UNIV SO CALIF,DEPT GEOL SCI,UNIV PK,LOS ANGELES,CA 90089, USA. NR 86 TC 297 Z9 299 U1 5 U2 29 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 11061 EP 11078 DI 10.1029/93JE00618 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600019 ER PT J AU GASKELL, RW AF GASKELL, RW TI MARTIAN SURFACE SIMULATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT WORKSHOP ON MARTIAL SURFACE ATMOSPHERE THROUGH TIME CY SEP 23-25, 1991 CL BOULDER, CO AB Computer generated surfaces have been created to aid in imaging, landing and rover studies for Mars and the moon. They are also being applied to the study of cratering histories. The surfaces are generated in steps which attempt to mimic geologic episodes. Surface roughness is realized fractally, while craters and other specific features have shapes and distributions dictated by observation. Surface materials are assigned appropriate albedos, making the images more realistic. With the inclusion of correlations between crater and rock distributions, the simulations are beginning to acquire a predictive capability. RP GASKELL, RW (reprint author), JET PROP LAB,MAIL STOP 301 125L,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 10 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 1993 VL 98 IS E6 BP 11099 EP 11103 DI 10.1029/93JE00617 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LK096 UT WOS:A1993LK09600021 ER PT J AU SKOLE, D TUCKER, C AF SKOLE, D TUCKER, C TI TROPICAL DEFORESTATION AND HABITAT FRAGMENTATION IN THE AMAZON - SATELLITE DATA FROM 1978 TO 1988 SO SCIENCE LA English DT Article ID ABANDONED PASTURES; EASTERN AMAZONIA; CARBON-DIOXIDE; AVHRR DATA; FORESTS; BRAZIL; BASIN; DIVERSITY; SCIENCE; LANDSAT AB Landsat satellite imagery covering the entire forested portion of the Brazilian Amazon Basin was used to measure, for 1978 and 1988, deforestation, fragmented forest, defined as areas less than 100 square kilometers surrounded by deforestation, and edge effects of 1 kilometer into forest from adjacent areas of deforestation. Tropical deforestation increased from 78,000 square kilometers in 1978 to 230,000 square kilometers in 1988 while tropical forest habitat, severely affected with respect to biological diversity, increased from 208,000 to 588,000 square kilometers. Although this rate of deforestation is lower than previous estimates, the effect on biological diversity is greater. C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. RP SKOLE, D (reprint author), UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,DURHAM,NH 03824, USA. NR 67 TC 912 Z9 958 U1 20 U2 232 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 25 PY 1993 VL 260 IS 5116 BP 1905 EP 1910 DI 10.1126/science.260.5116.1905 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LJ349 UT WOS:A1993LJ34900032 PM 17836720 ER PT J AU LEE, TJ RICE, JE AF LEE, TJ RICE, JE TI AB-INITIO STUDY OF THE CHLORINE NITRATE PROTONATION REACTION - IMPLICATIONS FOR LOSS OF CLONO2 IN THE STRATOSPHERE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; SULFURIC-ACID SURFACES; ATOMIC BASIS SETS; FIRST-ROW ATOMS; NITRIC-ACID; HETEROGENEOUS REACTIONS; MOLECULAR CALCULATIONS; HYDROGEN-CHLORIDE; OZONE DEPLETION; VIBRATIONAL-SPECTRUM AB The energetics of the protonation reaction of chlorine nitrate, ClONO2, have been investigated using state-of-the art ab initio quantum mechanical methods. Specifically, equilibrium structures, vibrational spectra, and thermochemical data have been obtained using second-order Moller-Plesset perturbation theory (MP2), singles and doubles coupled-cluster theory (CCSD), and the CCSD(T) method, which includes a preturbational estimate of the effects of connected triple excitations. It is shown that the lowest energy form of protonated ClONO2 corresponds to a complex between HOCl and NO2+-similar to the situation for HONO2 and CH3ONO2. The proton affinity of ClONO2 is determined to be 176.8 +/- 3 kcal/mol (0 K) while the second most stable isomer of protonated ClONO2 is 20 kcal/mol higher in energy. The HOCl...NO2+ complex is bound by 12.9 +/- 2 kcal/mol. The heat of formation of ClONO2 is computed to be 7.4 kcal/mol at 298 K, in good agreement with the experimental value of 6.3 kcal/mol. The present study supports a recent hypothesis that the reaction of ClONO2 on the surface of polar stratospheric clouds (PSCs) is proton catalyzed, although the specific mechanism is different. The results are also consistent with other recent findings concerning the reactions of ClONO2 and HOCl with HCl on the surface of PSCs. C1 IBM CORP, ALMADEN RES CTR, DIV RES, SAN JOSE, CA 95120 USA. RP LEE, TJ (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Rice, Julia/K-4928-2012; Lee, Timothy/K-2838-2012 OI Rice, Julia/0000-0001-5059-5127; NR 57 TC 52 Z9 52 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 24 PY 1993 VL 97 IS 25 BP 6637 EP 6644 DI 10.1021/j100127a012 PG 8 WC Chemistry, Physical SC Chemistry GA LV439 UT WOS:A1993LV43900012 ER PT J AU CHANDLER, M AF CHANDLER, M TI WARM CLIMATES - NOT JUST A LOT OF HOT AIR SO NATURE LA English DT Editorial Material ID OCEAN HEAT-TRANSPORT RP CHANDLER, M (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 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 24 PY 1993 VL 363 IS 6431 BP 673 EP 674 DI 10.1038/363673a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LJ339 UT WOS:A1993LJ33900030 ER PT J AU CHYBA, CF AF CHYBA, CF TI EXPLOSIONS OF SMALL SPACEWATCH OBJECTS IN THE EARTHS ATMOSPHERE SO NATURE LA English DT Article AB RECENT observations with the Spacewatch telescope indicate that the flux of Earth-crossing objects with diameters below about 50 m is some 10-100 times higher than predicted by simple extrapolation from the known main-belt asteroid population1,2. This might seem to imply3 a significantly greater terrestrial hazard from atmospheric explosions such as those that occurred over Revelstoke or Tunguska4,5. Here I show that explosions due to Spacewatch objects with diameters less than 50 m (having kinetic energies below about 10 megatonnes high-explosive equivalent) typically occur too high in the atmosphere to cause substantial surface damage. Exclusive of relatively rare iron objects, no comet or asteroid with an energy below approximately 2 megatonnes threatens the Earth's surface. The high flux of small Earth-crossing objects identified by Spacewatch therefore does not imply a greater terrestrial hazard. RP CHYBA, CF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693,GREENBELT,MD 20771, USA. NR 21 TC 25 Z9 25 U1 0 U2 2 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 24 PY 1993 VL 363 IS 6431 BP 701 EP 703 DI 10.1038/363701a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LJ339 UT WOS:A1993LJ33900049 ER PT J AU BUCKEY, JC GAFFNEY, FA LANE, LD LEVINE, BD BLOMQVIST, CG AF BUCKEY, JC GAFFNEY, FA LANE, LD LEVINE, BD BLOMQVIST, CG TI CENTRAL VENOUS-PRESSURE IN SPACE SO NEW ENGLAND JOURNAL OF MEDICINE LA English DT Letter C1 VANDERBILT UNIV,NASHVILLE,TN 37232. PRESBYTERIAN MED CTR,DALLAS,TX 75231. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BUCKEY, JC (reprint author), UNIV TEXAS,SW MED CTR,DALLAS,TX 75235, USA. NR 5 TC 53 Z9 54 U1 0 U2 1 PU MASS MEDICAL SOC PI BOSTON PA 10 SHATTUCK, BOSTON, MA 02115 SN 0028-4793 J9 NEW ENGL J MED JI N. Engl. J. Med. PD JUN 24 PY 1993 VL 328 IS 25 BP 1853 EP 1854 DI 10.1056/NEJM199306243282516 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA LH210 UT WOS:A1993LH21000026 PM 8502279 ER PT J AU ANDRAS, MT DURAJ, SA AF ANDRAS, MT DURAJ, SA TI REACTIVITY OF (ETA(7)-CYCLOHEPTATRIENYL)(ETA(5)-CYCLOPENTADIENYL)M (M=TI, NB) TOWARD DITHIOACETIC ACID - PREPARATION AND CHARACTERIZATION OF (ETA(5)-C5H5)TI(S2CCH3)3 AND (ETA(5)-C5H5)NB(ETA(2)-S2)(S2CCH3)2 SO INORGANIC CHEMISTRY LA English DT Article ID X-RAY STRUCTURE; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; COMPLEXES; NIOBIUM; 7-COORDINATE; COORDINATION; DERIVATIVES; TITANIUM; TANTALUM AB A method for the high-yield syntheses (up to 85%) of the two new compounds (eta5-C5H5)Ti(S2CCH3)3 (1) and (eta5-C5H5)Nb(eta2-S2)(S2CCH3)2 (2) from (eta7-C7H7)M(eta5-C5H5) (M = Ti, Nb) and dithioacetic acid, CH3CS2H, is described. Both compounds are characterized by elemental analysis, H-1 and C-13 NMR spectroscopy, infrared spectroscopy, mass spectrometry, and X-ray crystallography. Compound 1 crystallizes in orthorhombic space group Pbca with a = 16.964(5) angstrom, b = 24.545(10) angstrom, c = 7.832(2) angstrom, V = 3261(9) angstrom3, Z = 8, R = 0.0558, and R(W) = 0.0655. Compound 1 exists in the crystalline state as discrete seven-coordinate molecules; the coordination environment of the central Ti(IV) atom is a slightly distorted pentagonal bipyramid. A eta5-C5H5 ring occupies one axial site, two bidentate dithioacetate groups occupy four equatorial sites, and a third bidentate dithioacetate group spans the remaining axial and equatorial sites. The average equatorial Ti-S distance of 2.619 angstrom is appreciably longer than the axial Ti-S distance, 2.545(3) angstrom. Compound 2 crystallizes in space group P2(1)/c with a = 13.365(2) angstrom, b = 7.906(4) angstrom, c = 13.710(2) angstrom, beta = 96.44(3)-degrees, V = 1440(l) angstrom3, Z = 4, R = 0.038 49, and R(W) = 0.054 75. Crystals of 2 consist of discrete seven-coordinate molecules; the coordination environment of the central Nb(V) atom is a severely distorted pentagonal bipyramid. A eta5-C5H5 ring occupies one axial site, and a ''side-on' bonded disulfide, eta2-S2, occupies two equatorial sites. The remaining positions are occupied by two nonequivalent bidentate dithioacetate ligands. A variable-temperature H-1 NMR study on 2 shows rapid interconversion between the two dithioacetate environments at 47-degrees-C (DELTAG* = 17.1 +/- 0.1 kcal mol-1). C1 CLEVELAND STATE UNIV,DEPT CHEM,CLEVELAND,OH 44115. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 53 TC 8 Z9 8 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JUN 23 PY 1993 VL 32 IS 13 BP 2874 EP 2880 DI 10.1021/ic00065a013 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA LJ348 UT WOS:A1993LJ34800013 ER PT J AU LIN, TL PARK, JS GEORGE, T JONES, EW FATHAUER, RW MASERJIAN, J AF LIN, TL PARK, JS GEORGE, T JONES, EW FATHAUER, RW MASERJIAN, J TI LONG-WAVELENGTH PTSI INFRARED DETECTORS FABRICATED BY INCORPORATING A P+ DOPING SPIKE GROWN BY MOLECULAR-BEAM EPITAXY SO APPLIED PHYSICS LETTERS LA English DT Article AB By incorporating a 1-nm-thick p+ doping spike at the PtSi/Si interface, we have successfully demonstrated extended cutoff wavelengths of PtSi Schottky infrared detectors in the long wavelength infrared (LWIR) regime for the first time. The extended cutoff wavelengths resulted from the combined effects of an increased electric field near the silicide/Si interface due to the p+ doping spike and the Schottky image force. The p+ doping spikes were grown by molecular beam epitaxy at 450-degrees-C using elemental boron as the dopant source, with doping concentrations ranging from 5 X 10(19) to 2 X 10(20) cm-3. Transmission electron microscopy indicated good crystalline quality of the doping spikes. The cutoff wavelengths were shown to increase with increasing doping concentrations of the p+ spikes. Thermionic emission dark current characteristics were observed and photoresponses in the LWIR regime were demonstrated. RP LIN, TL (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 12 TC 32 Z9 39 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1993 VL 62 IS 25 BP 3318 EP 3320 DI 10.1063/1.109057 PG 3 WC Physics, Applied SC Physics GA LH607 UT WOS:A1993LH60700033 ER PT J AU YAO, H WOOLLAM, JA ALTEROVITZ, SA AF YAO, H WOOLLAM, JA ALTEROVITZ, SA TI SPECTROSCOPIC ELLIPSOMETRY STUDIES OF HF TREATED SI (100) SURFACES SO APPLIED PHYSICS LETTERS LA English DT Article ID HYDROGEN TERMINATION; SILICON; TEMPERATURE; DEPENDENCE; SI(111); OXIDE AB Both ex situ and in situ spectroscopic ellipsometry (SE) measurements have been employed to investigate the effects of HF cleaning on Si surfaces. The hydrogen-terminated (H-terminated) Si surface was modeled as an equivalent dielectric layer, and monitored in real time by SE measurements. The SE analyses indicate that after a 20-s 9:1 HF dip without rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed, in an ultrahigh vacuum (UHV) chamber, and analyzed by the in situ SE. Evidence for desorption of the H-terminated Si surface-layer, after being heated to approximately 550-degrees-C in the UHV chamber, is presented and discussed. This is the first use of an ex situ and in situ real-time, nondestructive technique capable of showing state of passivation, the rate of reoxidation, and the surface roughness of the H-terminated Si surfaces. C1 UNIV NEBRASKA,DEPT ELECT ENGN,LINCOLN,NE 68588. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP YAO, H (reprint author), UNIV NEBRASKA,CTR MICRELECTR & OPT MAT RES,LINCOLN,NE 68588, USA. NR 17 TC 44 Z9 46 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 21 PY 1993 VL 62 IS 25 BP 3324 EP 3326 DI 10.1063/1.109059 PG 3 WC Physics, Applied SC Physics GA LH607 UT WOS:A1993LH60700035 ER PT J AU BRAINERD, JJ AF BRAINERD, JJ TI THE SIGNATURE OF THE COSMOLOGICAL REDSHIFT IN POPULATION STUDIES OF GAMMA-RAY BURST SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, OBSERVATIONS; GAMMA RAYS, BURSTS AB The slope of a gamma-ray burst spectrum determines how the burst flux decreases as the cosmological red-shift z increases. This provides a test for the presence of a cosmological redshift in a sample of gamma-ray bursts. Many bursts have spectra characterized by a frequency-dependent power-law index, so a burst subset can be created by requiring that each subset member have a power-law index of the given value at a low frequency and an index of a different given value at a high frequency. If all bursts in this subset are at z much less than 0.1, then the flux at low frequency will change proportionally with the flux at high frequency. If, however, z > 0.1 for most bursts, then the linear dependence of the high-frequency flux on the low-frequency flux disappears at the flux characterizing the spatial cutoff in the log N-log C(max)/C(min) diagram. This signature of the cosmological redshift generally persists when gamma-ray bursts are given a broad distribution of intrinsic fluxes and spectral shapes. The characteristics that a burst distribution must have to mask the cosmological redshift are discussed. The limitations of this test are observational, arising primarily from errors in measuring the photon flux and in determining the spectral index of the burst spectrum. RP BRAINERD, JJ (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES-65,HUNTSVILLE,AL 35812, USA. NR 15 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 507 EP 514 DI 10.1086/172768 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500008 ER PT J AU MATTOX, JR BERTSCH, DL CHIANG, J DINGUS, BL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K SCHNEID, E SREEKUMAR, P THOMPSON, DJ AF MATTOX, JR BERTSCH, DL CHIANG, J DINGUS, BL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K SCHNEID, E SREEKUMAR, P THOMPSON, DJ TI THE EGRET DETECTION OF QUASAR-1633+382 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, OBSERVATIONS; QUASARS, INDIVIDUAL (1633+382) ID ACTIVE GALACTIC NUCLEI; SPECTRUM RADIO-SOURCES; GAMMA-RAY SOURCES; RELATIVISTIC JETS; X-RAY; 5 GHZ; ENERGY; TELESCOPE; RADIATION; QUASARS AB In the course of a full-sky survey, the EGRET instrument aboard the Compton Observatory detected an intense, high Galactic latitude source (GRO J1635+38), which is identified as OVV (optically violent variable) quasar 1633+382. The spectrum is represented by a power law with an energy spectral index of 0.9 between 30 MeV and 30 GeV. The gamma-ray power per decade is approximately 100 times larger than typical values at any longer wavelength. Significant variation of the gamma-ray flux density on a time scale as short as 2 days was observed, limiting the size of the region in which the gamma-rays are produced. Assuming the X-rays detected by the Einstein Observatory from this quasar are produced in the same region as the gamma-rays, and a similar X-ray flux density was extant at the time of the EGRET observation, the emission must be beamed to avoid a pair-production optical depth of approximately 10(4) which would exist otherwise. If beaming arises from bulk relativistic motion, the minimum Doppler factor required is 7.6. C1 COMP SCI CORP,ASTRON PROGRAMS,COMPTON OBSERV,CTR SCI SUPPORT,GREENBELT,MD. MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. HAMPDEN SYDNEY COLL,DEPT PHYS & ASTRON,HAMPDEN SYDNEY,VA 23943. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. STANFORD UNIV,HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. RP MATTOX, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; OI Thompson, David/0000-0001-5217-9135; Dingus, Brenda/0000-0001-8451-7450 NR 57 TC 139 Z9 142 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 609 EP 614 DI 10.1086/172778 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500018 ER PT J AU BREGMAN, J RANK, D SANDFORD, SA TEMI, P AF BREGMAN, J RANK, D SANDFORD, SA TEMI, P TI SPECTRAL IMAGING OF THE 3.3 AND 11.3 MICRON EMISSION BANDS IN NGC-1333 - DISCOVERY OF SPATIALLY SEPARATE BAND EMISSIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, INTERSTELLAR, LINES; ISM, INDIVIDUAL (NGC-1333); ISM, MOLECULES ID POLYCYCLIC AROMATIC-HYDROCARBONS; IRAS SOURCES; FEATURES; DUST AB Spectral images and aperture spectra were obtained of the nebula around the star SVS 3 in the star formation region NGC 1333. The spectra contain strong infrared emission bands originating from carbonaceous material. The spectra show the presence of the characteristic 3.3 and 11.3 mum emission features thought to be associated with C-H stretching and C-H out-of-plane bending modes, respectively, of polycyclic aromatic hydrocarbons (PAHs). The distribution of the 3.3 mum emission is suggestive of limb brightening from the edge of an emitting shell. The 3.3 and 11.3 mum emission features come from spatially distinct regions, with the 3.3 mum emission occurring outside the region of strongest 11.3 mum emission. Thus, the relative band strengths cannot be used to determine the excitation temperature and average size of the molecules. The relative distributions of the 3.3 and 11.3 mum emission features can be understood if the bands arise from PAH molecules of different sizes. Spectra in the 3 mum region of 4 positions around SVS 3, which sample regions of similar excitation, show 3.3 and 3.4 mum emission bands with the same relative intensities. The data mildly favor the identification of the 3.4 mum band with an excited mode of the C-H stretch (i.e., a hot band) or an overtone/combination rather than with the presence of molecular side groups on the PAHs, since the spectra are identical yet sample physically separate regions. C1 UNIV CALIF SANTA CRUZ,LICK OBSERV,MT HAMILTON,CA 95140. RP BREGMAN, J (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 26 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 668 EP 672 DI 10.1086/172783 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500023 ER PT J AU SMALE, AP DONE, C MUSHOTZKY, RF WEAVER, KA SERLEMITSOS, PJ MARSHALL, FE PETRE, R JAHODA, KM BOLDT, EA SWANK, JH SZYMKOWIAK, AE KELLEY, RL ARNAUD, K AF SMALE, AP DONE, C MUSHOTZKY, RF WEAVER, KA SERLEMITSOS, PJ MARSHALL, FE PETRE, R JAHODA, KM BOLDT, EA SWANK, JH SZYMKOWIAK, AE KELLEY, RL ARNAUD, K TI RESOLVING THE IRON K LINE IN CYGNUS-X-2 - AN OBSERVATION WITH BBXRT SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; STARS, INDIVIDUAL (CYGNUS X-2); X-RAYS, STARS ID X-RAY BINARIES; QUASI-PERIODIC OSCILLATIONS; ACTIVE GALACTIC NUCLEI; ENERGY-SPECTRA; COLD MATTER; X-2; EMISSION; CONTINUUM; MODELS; TENMA AB We present the first high-quality, moderate-resolution spectroscopy of Cygnus X-2 in the 0.4-12 keV energy range, obtained using the Broad Band X-Ray Telescope (BBXRT), part of the Astro-1 shuttle payload. These data enable us to resolve the physical width of the 6.7 keV Fe Kalpha feature in Cyg X-2 with an energy resolution a factor of 4 better than previous X-ray experiments. The feature is modeled well with a single broad Gaussian line with center energy E = 6.71(+0.23; -0.20), full width half-maximum 971(+505; -376) eV, and equivalent width 60 +/- 27 eV. There is also tentative evidence for Fe L line emission at 1 keV. A sensitive search for an iron edge feature in the 7-9 keV range results in an upper limit on the absorption depth of tau less-than-or-equal-to 0.15. There are three possible sites for the Fe Kalpha emission: the accretion disk, its corona, or the source itself. The last can be rejected as the continuum spectrum suggests that the central kT approximately 1.7 keV blackbody is Comptonized through tau approximately 20. Any line would thus be strongly downscattered, broadened, and lost. An origin in a corona covering the source and disk can also be ruled out as the observed broad line can be produced only in material with tau approximately 3, far in excess of the limits on the optical depth at the iron edge. A line from an optically thick corona out of the line of sight would be viewed only by reflection rather than transmission, so the photons would travel through tau approximately 1, also inconsistent with the lack of an iron edge. Reflection from the accretion disk itself, however, can produce a line of the observed energy, width, and equivalent width if the disk surface is highly ionized. C1 UNIV MARYLAND,COLL PK,MD 20742. RP SMALE, AP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 666,GREENBELT,MD 20771, USA. RI Swank, Jean/F-2693-2012; Kelley, Richard/K-4474-2012; done, chris/D-4605-2016 OI done, chris/0000-0002-1065-7239 NR 37 TC 31 Z9 31 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 796 EP 802 DI 10.1086/172796 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500036 ER PT J AU LESTRADE, JF PHILLIPS, RB HODGES, MW PRESTON, RA AF LESTRADE, JF PHILLIPS, RB HODGES, MW PRESTON, RA TI VLBI ASTROMETRIC IDENTIFICATION OF THE RADIO EMITTING REGION IN ALGOL AND DETERMINATION OF THE ORIENTATION OF THE CLOSE BINARY SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, ECLIPSING; RADIO CONTINUUM, STARS; STARS, INDIVIDUAL (BETA PERSEI); TECHNIQUES, INTERFEROMETRIC ID X-RAY-EMISSION; ECLIPSING BINARIES; SYSTEM ALGOL; BETA-LYRAE; STARS; POLARIZATION; TAURI AB A minute displacement of the radio source in Algol was measured by Very Long Baseline Interferometry (VLBI) during two consecutive orbital revolutions of the close binary. The magnitude of the displacement unambiguously indicates that the less massive star of the close binary, a K subgiant, is the star responsible for the nonthermal radio emission of the system. This is consistent with the idea that the radio emission in Algol is related to the strong magnetic activity of the subgiant. The orientation and sense of the displacement on the sky that are directly deduced from our astrometric VLBI observations imply (1) that the orbital plane of the close binary is at P.A. = + 52-degrees +/- 5-degrees (P.A. = 0-degrees is north and P.A. = 90-degrees is east) and (2) that the sense of circulation of the close binary is clockwise, as seen on the sky. Thus, the long-period and close binary orbital motions are almost orthogonal and counterrevolving and this is relevant for evolution and dynamical studies. The orientation and sense of circulation of the close binary determined by our VLBI observations are identical to the findings of Rudy (1979) and Kemp et al. (1981, 1983), obtained less directly with optical polarization observations. C1 OBSERV MEUDON,DERAD,F-92195 MEUDON,FRANCE. MIT,HAYSTACK OBSERV,WESTFORD,MA 01886. CALTECH,OWENS VALLEY RADIO OBSERV,BIG PINE,CA 93513. JET PROP LAB,PASADENA,CA 91109. RP LESTRADE, JF (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 33 TC 52 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 808 EP 814 DI 10.1086/172798 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500038 ER PT J AU DUVALL, TL JEFFERIES, SM HARVEY, JW OSAKI, Y POMERANTZ, MA AF DUVALL, TL JEFFERIES, SM HARVEY, JW OSAKI, Y POMERANTZ, MA TI ASYMMETRIES OF SOLAR OSCILLATION LINE-PROFILES SO ASTROPHYSICAL JOURNAL LA English DT Article DE LINE, PROFILES; SUN, OSCILLATIONS ID MODELS; WIDTHS AB Asymmetries of the power spectral line profiles of solar global p-modes are detected in full-disk intensity observations of the Ca II K Fraunhofer line. The asymmetry is a strong function of temporal frequency, nu, being strongest (almost-equal-to 10%) at the lowest frequencies observed (nu congruent-to 2 mHz) and vanishing near the peak of the power distribution (nu congruent-to 3.2 mHz). The variation with spherical harmonic degree is small. The asymmetry is interpreted in terms of a model in which the solar oscillation cavity is compared to a Fabry-Perot interferometer with the source slightly outside the cavity. A phase difference between an outward direct wave and a corresponding inward wave that passes through the cavity gives rise to the asymmetry. The asymmetry is different in velocity and intensity observations. Neglecting the asymmetry when modeling the power spectrum can lead to systematic errors in the measurement of mode frequencies of as much as 10(-4) of the mode frequency. The present observations and interpretation locate the source of the oscillations to be approximately 60 km beneath the photosphere, the shallowest position suggested to date. C1 UNIV DELAWARE, BARTOL RES INST, NEWARK, DE 19716 USA. NATL OPT ASTRON OBSERV, NATL SOLAR OBSERV, TUCSON, AZ 85726 USA. UNIV TOKYO, FAC SCI, DEPT CHEM ENGN, BUNKYO KU, TOKYO 113, JAPAN. RP NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 682, GREENBELT, MD 20771 USA. RI Duvall, Thomas/C-9998-2012 NR 28 TC 135 Z9 135 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP 829 EP 836 DI 10.1086/172800 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG695 UT WOS:A1993LG69500040 ER PT J AU GANGA, K CHENG, E MEYER, S PAGE, L AF GANGA, K CHENG, E MEYER, S PAGE, L TI CROSS-CORRELATION BETWEEN THE 170 GHZ SURVEY MAP AND THE COBE DIFFERENTIAL MICROWAVE RADIOMETER 1ST-YEAR MAPS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND ID BACKGROUND ANISOTROPY; MILLIMETER AB This Letter describes results of a cross-correlation between the 170 GHz partial-sky survey, made with a 3.8-degrees beam balloon-borne instrument, and the COBE DMR ''Fit Technique'' reduced galaxy all-sky map with a beam of 7-degrees. The strong correlation between the data sets implies that the observed structure is consistent with thermal variations in a 2.7 K emitter. We describe a number of tests of the correlation: (1) A chi2 analysis applied to the correlation function rules out the assumption that there is no structure in either of the two maps. (2) A second test shows that if the DMR map has structure but the 170 GHz map does not, the probability of obtaining the observed correlation is small. (3) Further analyses support the assumption that both maps have structure and that the 170 GHz-DMR cross-correlation is consistent with the analogous DMR correlation function. (4) Maps containing various combinations of noise and Harrison-Zel'dovich power spectra are simulated and correlated to reinforce the result. Because these two experiments use completely different observing strategies, observing frequencies, and data reduction methods, the correlation provides compelling evidence that both instruments have observed fluctuations consistent with anisotropies in the cosmic microwave background. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP GANGA, K (reprint author), PRINCETON UNIV,JOSEPH HENRY LABS,JADWIN HALL,PRINCETON,NJ 08544, USA. NR 18 TC 86 Z9 86 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP L57 EP L60 DI 10.1086/186879 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG697 UT WOS:A1993LG69700001 ER PT J AU GORSKI, KM AF GORSKI, KM TI EXPERIMENT-SPECIFIC COSMIC MICROWAVE BACKGROUND CALCULATIONS MADE EASIER - APPROXIMATION FORMULA FOR SMOOTHED DELTA-T/T WINDOWS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND ID ANISOTROPY; RADIATION AB An approximation formula for the spectral windows involved in the experiment-specific cosmic microwave background anisotropy calculations is introduced and tested in an application to cold dark matter theory signal predictions for the current anisotropy experiments. C1 KYOTO UNIV,UJI RES CTR,YUKAWA INST THEORET PHYS,KYOTO 606,JAPAN. RP GORSKI, KM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 6859,GREENBELT,MD 20771, USA. NR 15 TC 10 Z9 10 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP L65 EP L69 DI 10.1086/186881 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG697 UT WOS:A1993LG69700003 ER PT J AU HAAS, MR GLASSGOLD, AE AF HAAS, MR GLASSGOLD, AE TI DETECTION OF O-I AND SI-II FAR-INFRARED FINE-STRUCTURE EMISSION FROM ALPHA-ORIONIS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, STARS; STARS, INDIVIDUAL (ALPHA-ORIONIS); STARS, MASS LOSS; SUPERGIANTS ID CIRCUMSTELLAR ENVELOPE; REGIONS; MICRON; IONIZATION; SHELLS; MODEL; DUST; CO AB We have detected [O I] 63 mum and [Si II] 35 mum emission from the oxygen-rich, M2 Iab supergiant, alpha Orionis (Betelgeuse). The [O I] line flux is 2.4 +/- 0.2 x 10(-18) W cm-2, and the [Si II] line flux is 0.9 +/- 0.4 x 10(-18) W cm-2. These fluxes are consistent with the thermal model of Rodgers & Glassgold, which indicates that the emission arises in dense, warm gas in alpha Ori's inner envelope and implies that nearly all of the available O and Si is in atomic form. This is the first reported detection of far-infrared, fine-structure emission from the inner or transition region of a circumstellar envelope, where molecules and dust are expected to form. C1 NYU,DEPT PHYS,NEW YORK,NY 10003. RP HAAS, MR (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 38 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP L111 EP L114 DI 10.1086/186892 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG697 UT WOS:A1993LG69700014 ER PT J AU STECKER, FW SALAMON, MH MALKAN, MA AF STECKER, FW SALAMON, MH MALKAN, MA TI THE HIGH-ENERGY DIFFUSE COSMIC GAMMA-RAY BACKGROUND-RADIATION FROM BLAZARS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, THEORY; GALAXIES, ACTIVE; QUASARS, GENERAL ID ACTIVE GALACTIC NUCLEI; STATISTICAL-METHODS; ASTRONOMICAL DATA; UPPER LIMITS; GALAXIES AB We predict the spectrum and flux of the high-energy diffuse cosmic gamma-ray background radiation produced by blazars. Our calculations are based on the Compton Observatory EGRET observations of high-energy gamma-rays from these objects, the Whipple observation of TeV gamma-rays from Mrk 421, and radio population studies of flat-spectrum radio sources. Our statistical analysis gives the result L(gamma) is-proportional-to L(radio)1.2 +/- 0.1, consistent with a linear correlation. We then use the radio luminosity function and redshift evolution to calculate the gamma-ray background. We find that blazars cannot account for the flux level or steep spectrum of the background observed by SAS 2 in the sub-GeV range, but could likely provide the dominant background component in the multi-GeV energy range and above. We predict a differential photon spectral index for this component of approximately 2 up to approximately 10 GeV. Above that energy, the spectrum should gradually steepen owing to pair production by interactions of the gamma-rays with intergalactic infrared photons. Using the calculations of this effect by Stecker, de Jager, & Salamon, we estimate a spectral index of approximately 3.5 for energies above a TeV. C1 UNIV UTAH,DEPT PHYS,SALT LAKE CITY,UT 84112. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. RP STECKER, FW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Stecker, Floyd/D-3169-2012 NR 31 TC 60 Z9 60 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1993 VL 410 IS 2 BP L71 EP L71 DI 10.1086/186882 PN 2 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG697 UT WOS:A1993LG69700004 ER PT J AU KO, MKW SZE, ND WANG, WC SHIA, G GOLDMAN, A MURCRAY, FJ MURCRAY, DG RINSLAND, CP AF KO, MKW SZE, ND WANG, WC SHIA, G GOLDMAN, A MURCRAY, FJ MURCRAY, DG RINSLAND, CP TI ATMOSPHERIC SULFUR-HEXAFLUORIDE - SOURCES, SINKS AND GREENHOUSE WARMING SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TRACE GASES; LIFETIME EXPERIMENT; LOWER STRATOSPHERE; POLAR VORTEX; SF6; TRENDS; INTENSITIES; ABSORPTION AB Model calculations using estimated reaction rates of sulfur hexafluoride (SF6) with OH and O(1D) indicate that the atmospheric lifetime due to these processes may be very long (25,000 years). An upper limit for the UV cross section would suggest a photolysis lifetime much longer than 1000 years. The possibility of other removal mechanisms are discussed. The estimated lifetimes are consistent with other estimated values based on recent laboratory measurements. There appears to be no known natural source of SF6. An estimate of the current production rate of SF6 is about 5 kt/yr. Based on historical emission rates, we calculated a present-day atmospheric concentrations for SF6 of about 2.5 parts per trillion by volume (pptv) and compared the results with available atmospheric measurements. It is difficult to estimate the atmospheric lifetime of SF6 based on mass balance of the emission rate and observed abundance. There are large uncertainties concerning what portion of the SF6 is released to the atmosphere. Even if the emission rate were precisely known, it would be difficult to distinguish among lifetimes longer than 100 years since the current abundance of SF6 is due to emission in the past three decades. More information on the measured trends over the past decade and observed vertical and latitudinal distributions of SF6 in the lower stratosphere will help to narrow the uncertainty in the lifetime. Based on laboratory-measured IR absorption cross section for SF6, we showed that SF6 is about 3 times more effective as a greenhouse gas compared to CFC 11 on a per molecule basis. However, its effect on atmospheric warming will be minimal because of its very small concentration. We estimated the future concentration of SF6 at 2010 to be 8 and 10 pptv based on two projected emission scenarios. The corresponding equilibrium warming of 0.0035-degrees-C and 0.0043-degrees-C is to be compared with the estimated warming due to CO2 increase of about 0.8-degrees-C in the same period. C1 UNIV DENVER, DEPT PHYS, DENVER, CO 80208 USA. NASA, LANGLEY RES CTR, CTR ATMOSPHER SCI, HAMPTON, VA 23681 USA. ALLIED SIGNAL INC, BUFFALO RES LAB, BUFFALO, NY 14210 USA. SUNY Albany, ALBANY, NY 12222 USA. RP KO, MKW (reprint author), ATMOSPHER & ENVIRONM RES INC, 840 MEMORIAL DR, CAMBRIDGE, MA 02139 USA. RI Ko, Malcolm/D-5898-2015 NR 45 TC 74 Z9 76 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10499 EP 10507 DI 10.1029/93JD00228 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000015 ER PT J AU MCDERMID, IS AF MCDERMID, IS TI A 4-YEAR CLIMATOLOGY OF STRATOSPHERIC OZONE FROM LIDAR MEASUREMENTS AT TABLE MOUNTAIN, 34.4-DEGREES-N SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SYSTEMS AB Regular measurements of stratospheric ozone concentration profiles have been made at Table Mountain, California, since February 1988. During the period up to the end of December 1991, 435 independent profiles were measured by the differential absorption lidar technique. These long-term results and an evaluation of their quality are presented in this paper. The large number of measurements made has allowed the development of a short-term, 4-year, climatology of the ozone concentration profile at this specific location (34.4-degrees-N, - 117.7-degrees-W). The effects of the eruption of Mount Pinatubo were not observed in the lidar measurements until August 1991 and the results presented here can essentially be considered as the pre-Pinatubo climatology. RP MCDERMID, IS (reprint author), CALTECH,JET PROPULS LAB,TABLE MTN FACIL,POB 367,WRIGHTWOOD,CA 92397, USA. NR 8 TC 11 Z9 11 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10509 EP 10515 DI 10.1029/93JD00199 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000016 ER PT J AU MLYNCZAK, MG SOLOMON, S AF MLYNCZAK, MG SOLOMON, S TI A DETAILED EVALUATION OF THE HEATING EFFICIENCY IN THE MIDDLE ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NONLOCAL THERMODYNAMIC-EQUILIBRIUM; EXOTHERMIC CHEMICAL-REACTIONS; LOWER THERMOSPHERE; ENERGY-TRANSFER; VIBRATIONAL-RELAXATION; V3 MODE; OZONE; OH; O2; NIGHTGLOW AB The conversion to heat of solar ultraviolet radiation absorbed by ozone and molecular oxygen in the terrestrial mesosphere and lower thermosphere occurs through a series of complex processes. Upon photolysis of the O3 or O2, significant amounts of chemical potential energy and atomic and molecular internal energy are generated. The disposition of the internal energy largely determines the rate at which the atmosphere is heated. In addition, the chemical energy is released subsequent to exothermic chemical reactions which may occur long after and far away from the location of photon deposition. Energy may be lost from the atmosphere by airglow from excited photolysis products or by chemiluminescent emission from product species of exothermic chemical reactions. In this paper we examine the role of airglow losses in reducing the efficiency of solar heating in the Hartley, Huggins, and Chappuis bands of ozone and in the Herzberg, Ly alpha, Schumann-Runge continuum, and Schumann-Runge bands of molecular oxygen. We also examine the role of heating due to seven chemical reactions and calculate the efficiencies for those reactions with significant chemiluminescent loss. Parameterizations of the heating efficiency that are readily applicable to numerical models are given for those processes with nonunit efficiencies. Results from the calculation of heating rates for individual processes indicate that the reaction of atomic hydrogen and ozone is potentially the largest single source of heat in the vicinity of the mesopause. However, significant improvement is still needed in the knowledge of the quenching and chemical reaction rates of vibrationally excited OH before the efficiency of this reaction can be confidently calculated. Our calculations also indicate that even under strong quenching, most of the OH is in vibrationally excited form above 85-90 km. Finally, the bulk heating efficiency due to the combination of solar and chemical heating is calculated. The calculated bulk efficiencies demonstrate that airglow and chemiluminescent emission significantly reduce the amount of energy available for heat throughout the mesosphere and lower thermosphere. C1 NOAA,AERON LAB,BOULDER,CO 80303. RP MLYNCZAK, MG (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 401B,HAMPTON,VA 23681, USA. RI Mlynczak, Martin/K-3396-2012 NR 79 TC 190 Z9 191 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10517 EP 10541 DI 10.1029/93JD00315 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000017 ER PT J AU HALL, TM PRATHER, MJ AF HALL, TM PRATHER, MJ TI SIMULATIONS OF THE TREND AND ANNUAL CYCLE IN STRATOSPHERIC CO2 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; ANTARCTIC OZONE; ARCTIC VORTEX; TRANSPORT; MODEL; TROPOSPHERE; EXCHANGE; IMPACT; AIR AB The distribution and evolution of stratospheric CO2 in response to the observed annual cycle, interannual variations, and long-term trends in tropospheric CO2 is simulated with the GISS 23 layer stratospheric general circulation model. Carbon dioxide is a tracer of stratospheric transport which has essentially no local sources or sinks but still displays gradients due to the forcing at the surface. Consequently, observations of stratospheric CO2, until recently limited to a few flask samples, but now included as high frequency in situ sampling in aircraft campaigns, provide a test of tracer transport in stratospheric simulations independent of model chemistry. In our model, CO2 enters the stratosphere primarily through the tropical tropopause, where air parcels are effectively labeled in time by their CO2 values (although not uniquely because of the cycles in tropospheric concentration). Parcels of differing ages are subsequently mixed in the stratosphere. Only when the growth is purely linear can the CO2 offset in a parcel relative to the troposphere be interpreted as the average time since stratospheric air was last in contact with the troposphere, i.e., the ''age'' of the stratosphere. Our model is in qualitative agreement with multiyear averages of balloon soundings at northern mid- and high latitudes; the stratosphere at 30 km at mid-latitudes is about 4 years (6 ppm of CO2) behind the troposphere. We predict significant propagation of the CO2 annual cycle into the lower stratosphere, an effect which must be accounted for when interpreting observations. While the annual cycle is negligible above the lower stratosphere, interannual oscillations, such as those associated with El Ninos, can propagate well into the middle stratosphere as positive offsets from the linear trend lasting significantly longer than their duration in the troposphere. C1 UNIV CALIF IRVINE,DEPT GEOSCI,IRVINE,CA 92717. RP HALL, TM (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 30 TC 43 Z9 43 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10573 EP 10581 DI 10.1029/93JD00325 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000020 ER PT J AU REBER, CA TREVATHAN, CE MCNEAL, RJ LUTHER, MR AF REBER, CA TREVATHAN, CE MCNEAL, RJ LUTHER, MR TI THE UPPER-ATMOSPHERE RESEARCH SATELLITE (UARS) MISSION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The Upper Atmosphere Research Satellite (UARS) is a NASA program aimed at improving our knowledge of the physical and chemical processes controlling the stratosphere, mesosphere, and lower thermosphere, emphasizing those levels that are known to be particularly susceptible to change by human activities. The spacecraft was launched by the Space Shuttle Discovery on September 12, 1991, into a near-circular orbit at 585 km altitude and 57-degrees inclination. Measurements include vertical profiles of temperature, many trace gases, and horizontal wind velocities, as well as solar energy inputs. Many of the limb-scanning instruments can measure to as high as 80-degrees latitude, providing near-global coverage. The mission is supported by a large international correlative measurement program, yielding data both for validation of the UARS measurements and for complementary scientific studies. A dedicated data system provides rapid processing to geophysical quantities and makes these data available to UARS scientists. C1 NASA HEADQUARTERS,WASHINGTON,DC 20546. RP REBER, CA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 910,GREENBELT,MD 20771, USA. NR 2 TC 128 Z9 132 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10643 EP 10647 DI 10.1029/92JD02828 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000025 ER PT J AU BARATH, FT CHAVEZ, MC COFIELD, RE FLOWER, DA FRERKING, MA GRAM, MB HARRIS, WM HOLDEN, JR JARNOT, RF KLOEZEMAN, WG KLOSE, GJ LAU, GKK LOO, MS MADDISON, BJ MATTAUCH, RJ MCKINNEY, RP PECKHAM, GE PICKETT, HM SIEBES, G SOLTIS, FS SUTTIE, RA TARSALA, JA WATERS, JW WILSON, WJ AF BARATH, FT CHAVEZ, MC COFIELD, RE FLOWER, DA FRERKING, MA GRAM, MB HARRIS, WM HOLDEN, JR JARNOT, RF KLOEZEMAN, WG KLOSE, GJ LAU, GKK LOO, MS MADDISON, BJ MATTAUCH, RJ MCKINNEY, RP PECKHAM, GE PICKETT, HM SIEBES, G SOLTIS, FS SUTTIE, RA TARSALA, JA WATERS, JW WILSON, WJ TI THE UPPER-ATMOSPHERE RESEARCH SATELLITE MICROWAVE LIMB SOUNDER INSTRUMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC MEASUREMENTS; OZONE AB The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centered near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for ''total power'' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met. C1 RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. UNIV VIRGINIA, CHARLOTTESVILLE, VA 22903 USA. HERIOT WATT UNIV, EDINBURGH EH1 1HX, MIDLOTHIAN, SCOTLAND. RP BARATH, FT (reprint author), JET PROP LAB, PASADENA, CA 91109 USA. NR 22 TC 221 Z9 229 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10751 EP 10762 DI 10.1029/93JD00798 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000032 ER PT J AU RUSSELL, JM GORDLEY, LL PARK, JH DRAYSON, SR HESKETH, WD CICERONE, RJ TUCK, AF FREDERICK, JE HARRIES, JE CRUTZEN, PJ AF RUSSELL, JM GORDLEY, LL PARK, JH DRAYSON, SR HESKETH, WD CICERONE, RJ TUCK, AF FREDERICK, JE HARRIES, JE CRUTZEN, PJ TI THE HALOGEN OCCULTATION EXPERIMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE AB The Halogen Occultation Experiment (HALOE) was launched on the Upper Atmosphere Research Satellite (UARS) spacecraft September 12, 1991, and after a period of outgassing, it began science observations October 11. The experiment uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the Earth limb. Latitudinal coverage is from 80-degrees-S to 80-degrees-N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to almost-equal-to 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere. C1 GATS INC,HAMPTON,VA. UNIV MICHIGAN,ANN ARBOR,MI 48105. SPACE TEC VENTURES INC,HAMPTON,VA. UNIV CALIF IRVINE,IRVINE,CA 92717. NOAA,AERON LAB,BOULDER,CO 80303. UNIV CHICAGO,CHICAGO,IL 60637. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. MAX PLANCK INST CHEM,W-6500 MAINZ,GERMANY. RP RUSSELL, JM (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401B,HAMPTON,VA 23651, USA. RI Tuck, Adrian/F-6024-2011; Crutzen, Paul/F-6044-2012 OI Tuck, Adrian/0000-0002-2074-0538; NR 16 TC 679 Z9 686 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1993 VL 98 IS D6 BP 10777 EP 10797 DI 10.1029/93JD00799 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ840 UT WOS:A1993LJ84000034 ER PT J AU EAGLES, DM AF EAGLES, DM TI SPECIFIC-HEATS AND THERMODYNAMIC CRITICAL FIELDS IN ZN-DOPED YBA2CU3O7-X ACCORDING TO AN INDUCED-PAIRING MODEL SO PHYSICA C LA English DT Article ID HIGH-TC SUPERCONDUCTORS; HIGH-TEMPERATURE SUPERCONDUCTORS; HOLE LIQUID MODEL; 2-COMPONENT SUPERCONDUCTIVITY; NORMAL STATE; HALL NUMBER; TRANSITION; ENERGY; GAP; PHENOMENOLOGY AB Electronic specific heats and thermodynamic critical fields are calculated in a mean-field version of an induced-pairing model for superconductivity, and compared with results of Loram et al. on YBa2(Cu1-yZny)3O7-x. This model involves induction of pairing of holes in a wide band by strongly bound electron-like pairs. It is assumed that the planar hole concentration for no Zn addition is close to, but slightly higher than, that for the maximum T(c), and that it increases by 0.015 per planar Cu ion for each increase of y by 0.01. Parameters of the model are taken to be the same as in a previous publication in which energy gaps were discussed, except that an effective hybridization parameter is adjusted for each Zn concentration to give agreement with the observed T(c). Results are presented for y=0.0, 0.01 and 0.03. The agreement with experiment is good for thermodynamic critical fields, and is fair for specific heats. For specimens with larger y, with relatively low T(c)'s, it is argued that the model should be supplemented to include effects of a BCS-type interaction amongst the wide-band carriers. RP EAGLES, DM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,CODE ES 74,HUNTSVILLE,AL 35812, USA. NR 54 TC 7 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN 20 PY 1993 VL 211 IS 3-4 BP 319 EP 328 DI 10.1016/0921-4534(93)90138-G PG 10 WC Physics, Applied SC Physics GA LK864 UT WOS:A1993LK86400006 ER PT J AU JACOBS, SS COMISO, JC AF JACOBS, SS COMISO, JC TI A RECENT SEA-ICE RETREAT WEST OF THE ANTARCTIC PENINSULA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WEDDELL SEA AB Satellite passive microwave data show a record decrease in sea ice extent in the Bellingshausen Sea from mid-1988 through early 1991. The change coincides with more southerly surface winds, increased cyclonic activity and rising surface air temperatures, which reached historic highs along the west coast of the Antarctic Peninsula in 1989. Preceded by high ice cover in 1986-87, the retreat was most evident during summer in the formerly perennial sea-ice field over the continental shelf. Ocean heat storage probably contributed to the persistence and coastal propagation of this anomaly. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP JACOBS, SS (reprint author), COLUMBIA UNIV,LAMONT DOHERTY EARTH OBSERV,PALISADES,NY 10964, USA. NR 27 TC 62 Z9 63 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1171 EP 1174 DI 10.1029/93GL01200 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800016 ER PT J AU ROSENFIELD, JE AF ROSENFIELD, JE TI RADIATIVE FEEDBACK OF POLAR STRATOSPHERIC CLOUDS ON ANTARCTIC TEMPERATURES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC HEATING RATE; OZONE HOLE; PARAMETERIZATION; ABSORPTION; MODEL AB A one-dimensional time marching radiative transfer model has been used to investigate the potential effects of polar stratospheric clouds (PSCs) on winter and spring temperatures in the Antarctic lower stratosphere. High, middle, and low PSC amounts were specified from lidar backscatter profiles and were chosen to represent the likely range of PSC amounts present in the Antarctic region. The computed effects of the PSCs on temperatures depend strongly on the surface temperature and on the extent of tropospheric cloudiness, and range from a maximum increase of 6 K for a high amount of PSCs over a warm surface and clear troposphere to a maximum decrease of 2 K for a high amount of PSCs over a cold surface and a troposphere with high clouds. The average effect is unlikely to be more than a 1 or 2 K temperature change. RP ROSENFIELD, JE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 916,GREENBELT,MD 20771, USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1195 EP 1198 DI 10.1029/93GL01350 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800022 ER PT J AU HESSE, M WINSKE, D AF HESSE, M WINSKE, D TI HYBRID SIMULATIONS OF COLLISIONLESS ION TEARING SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC RECONNECTION; MODE; INSTABILITIES; PLASMAS AB Ion tearing in a thin collisionless neutral sheet is investigated using hybrid (particle ion, massless fluid electron) simulations in which dissipation effects are included through a model of the full electron pressure tensor in which self-consistently generated anisotropies are reduced via an isotropization time factor. The linear growth rates and ion dynamics are in qualitative agreement with linear theory and one-component simulations. The reconnection rate increases with the isotropization time. C1 LOS ALAMOS NATL LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545. RP HESSE, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ELECTRODYNAM BRANCH,CODE 696,GREENBELT,MD 20771, USA. RI Hesse, Michael/D-2031-2012 NR 19 TC 38 Z9 38 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1207 EP 1210 DI 10.1029/93GL01250 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800025 ER PT J AU REBER, CA AF REBER, CA TI THE UPPER-ATMOSPHERE RESEARCH SATELLITE (UARS) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The Upper Atmosphere Research Satellite (UARS) was launched by the Space Shuttle on September 12, 1991 into a near circular orbit at 585 km altitude inclined 57 degrees to the Equator. Measurements were initiated a few days later, including solar energy inputs to the atmosphere and vertical profiles of temperature, important minor gas species, and wind fields. The orbital parameters, combined with the sensor measurements characteristics, yield a measurement pattern that produces near global coverage with a duty cycle that periodically favors the Northern or the Southern hemispheres. A few spacecraft and instrument anomalies have impacted the total amount of data obtained to date, but the overall performance of the mission has been very good. RP REBER, CA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 4 TC 88 Z9 88 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1215 EP 1218 DI 10.1029/93GL01103 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800027 ER PT J AU WATERS, JW FROIDEVAUX, L MANNEY, GL READ, WG ELSON, LS AF WATERS, JW FROIDEVAUX, L MANNEY, GL READ, WG ELSON, LS TI MLS OBSERVATIONS OF LOWER STRATOSPHERIC CLO AND O3 IN THE 1992 SOUTHERN-HEMISPHERE WINTER SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE AB UARS MLS measurements of ClO in the 1992 southern hemisphere winter are described. Lower stratospheric ClO abundances greater than 1 ppbv were observed in the vortex beginning 1 June. The enhanced ClO reached largest areal extent in mid-August, then retreated poleward. ClO abundances at 22 hPa decreased in early September while those at 46 hPa remained high. O3 decrease within the vortex was observed by mid-August, and was coincident with the enhanced ClO. RP WATERS, JW (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 9 TC 48 Z9 48 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1219 EP 1222 DI 10.1029/93GL01447 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800028 ER PT J AU TUCK, AF RUSSELL, JM HARRIES, JE AF TUCK, AF RUSSELL, JM HARRIES, JE TI STRATOSPHERIC DRYNESS - ANTIPHASED DESICCATION OVER MICRONESIA AND ANTARCTICA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WATER-VAPOR; LATE WINTER; LIMS AB HALOE observations of water vapor and methane during the period 21 September - 15 October 1992 are used to examine the role of Antarctic drying in the lower stratosphere. Zonal mean cross-sections of [2 CH4 + H2O] show the probability of transport of Antarctic type dryness to latitudes as distant as 20-degrees-N, with major water vapor deficits evident between 10 and 100 mb to 10-degrees-S. Examination of monthly mean tropical 100 mb temperatures and of Antarctic temperatures suggests that the observations are consistent with stratospheric dryness being achieved by the combined effects of tropopause freeze-drying over the Micronesia region during northern winter and drying through the influence of the very low temperatures over Antarctica during southern winter. This paper presents these intriguing new results, and offers a possible explanation. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. RP TUCK, AF (reprint author), NOAA,AERON LAB,BOULDER,CO 80303, USA. RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 17 TC 38 Z9 38 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1227 EP 1230 DI 10.1029/93GL00824 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800030 ER PT J AU HARWOOD, RS CARR, ES FROIDEVAUX, L JARNOT, RF LAHOZ, WA LAU, CL PECKHAM, GE READ, WG RICAUD, PD SUTTIE, RA WATERS, JW AF HARWOOD, RS CARR, ES FROIDEVAUX, L JARNOT, RF LAHOZ, WA LAU, CL PECKHAM, GE READ, WG RICAUD, PD SUTTIE, RA WATERS, JW TI SPRINGTIME STRATOSPHERIC WATER-VAPOR IN THE SOUTHERN-HEMISPHERE AS MEASURED BY MLS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE; TRANSPORT; MODEL AB The effects of the break-up of the antarctic vortex on the water vapour distribution are studied using MLS measurements of water vapour made during September 1991 and November 1991. In early November at 22 hPa a moist area is found within the polar vortex, consistent with an observed descent of order 10 km and strong radiative cooling. As the vortex erodes (beginning of November 1991), parcels of moist air become detached from the edge of the vortex and mix rapidly (within 2-3 days) with drier mid-latitude air. When the vortex breaks up (mid-November), larger parcels of moist air from both the edge and the inner vortex migrate to mid-latitudes. These parcels have a longer lifetime than those produced by vortex erosion, probably because they are correlated with higher potential vorticity gradients. The break-up of the vortex is accompanied by a mean adiabatic equatorward transport resulting in a significant increase in midstratospheric water vapour values at mid-latitudes in late spring. C1 JET PROP LAB,PASADENA,CA 91109. HERIOT WATT UNIV,DEPT PHYS,EDINBURGH EH1 1HX,MIDLOTHIAN,SCOTLAND. RP HARWOOD, RS (reprint author), UNIV EDINBURGH,DEPT METEOROL,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. NR 13 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1235 EP 1238 DI 10.1029/93GL00832 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800032 ER PT J AU TUCK, AF HOVDE, SJ KELLY, KK RUSSELL, JM WEBSTER, CR MAY, RD AF TUCK, AF HOVDE, SJ KELLY, KK RUSSELL, JM WEBSTER, CR MAY, RD TI INTERCOMPARISON OF HALOE AND ER-2 AIRCRAFT H2O AND CH4 OBSERVATIONS COLLECTED DURING THE 2ND AIRBORNE ARCTIC STRATOSPHERIC EXPERIMENT (AASE-II) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB HALOE observations of H2O and CH4 are compared with in situ techniques aboard the ER-2 aircraft during the northern winter of 1991/92, in particular for the dates 911208, 920108, 920217, 920222 and 920320 when the spatial coincidences are close, within +/-1-degrees latitude and +/-12-degrees longitude. The temporal coincidence is within 4 hours. The version 9 retrievals of HALOE profiles are used, since they contain a self-consistent aerosol correction. The results reveal the limitations of comparing high resolution in situ aircraft data with a remote sounding limb scanner. Of the 5 comparison dates, 3 had HALOE/ER-2 coincidences which occurred near the edge of the Arctic vortex (911208, 920108, 920217); the vertical variability in the HALOE results and the horizontal variability in the ER-2 observations on these days show that the vortex edge is not a region where exact agreement can be expected except by chance. On a 4th comparison date, there was substantial overlap away from the vortex edge, although for some species the aircraft data show considerable variability near the coincidence point. On the 5th comparison date, the ER-2 had no overlap in altitude with the lowest HALOE observations; however, a short linear interpolation over approximately 1 km altitude results in smooth composite profiles. Generally speaking the agreement between HALOE and the ER-2 at overlap altitudes is about 12% in the case of water vapor, which shows low horizontal and vertical variability. The difference was shown to contain atmospheric variability in one case by using the HALOE viewpath superimposed on a potential vorticity map to to examine a pair of HALOE observations straddling the coincidence point in longitude. The agreement for methane, with limited data having altitude overlap, is better than 6%. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. NOAA,AERON LAB,BOULDER,CO 80303. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. JET PROP LAB,PASADENA,CA 91109. RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 4 TC 5 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1243 EP 1246 DI 10.1029/93GL00825 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800034 ER PT J AU FISHBEIN, EF ELSON, LS FROIDEVAUX, L MANNEY, GL READ, WG WATERS, JW ZUREK, RW AF FISHBEIN, EF ELSON, LS FROIDEVAUX, L MANNEY, GL READ, WG WATERS, JW ZUREK, RW TI MLS OBSERVATIONS OF STRATOSPHERIC WAVES IN TEMPERATURE AND O3 DURING THE 1992 SOUTHERN WINTER SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE; HEMISPHERE AB The Microwave Limb Sounder observed waves in stratospheric temperature and O3 during the 1992 southern winter. Wave 1 intensifies three times from mid August through mid September, when a 9 day eastward traveling wave becomes in phase with the stationary wave 1. During the periods of wave intensification, minor sudden warmings and increased zonal mean O3 are observed. The waves have a westward phase tilt which results in an intensified baroclinic zone when the waves are in phase. Waves in T and O3 are. positively correlated near 5 - 10 hPa, implying transport by planetary waves; this is supported by larger O3 wave amplitudes than expected from photochemistry alone. RP FISHBEIN, EF (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 13 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1255 EP 1258 DI 10.1029/93GL01110 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800037 ER PT J AU BURRAGE, MD SKINNER, WR MARSHALL, AR HAYS, PB LIEBERMAN, RS FRANKE, SJ GELL, DA ORTLAND, DA MORTON, YT SCHMIDLIN, FJ VINCENT, RA WU, DL AF BURRAGE, MD SKINNER, WR MARSHALL, AR HAYS, PB LIEBERMAN, RS FRANKE, SJ GELL, DA ORTLAND, DA MORTON, YT SCHMIDLIN, FJ VINCENT, RA WU, DL TI COMPARISON OF HRDI WIND MEASUREMENTS WITH RADAR AND ROCKET OBSERVATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POKER-FLAT; TEMPERATURE; MESOSPHERE; DYNAMICS; ALASKA AB Wind fields in the mesosphere and lower thermosphere are obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) by observing the Doppler shifts of emission lines in the O2 Atmospheric band. The validity of the measured winds depends on an accurate knowledge of the positions on the detector of the observed lines in the absence of a wind induced Doppler shift. These positions have been determined to an accuracy of approximately 5 ms-1 from the comparison of winds measured by HRDI with those obtained by MF radars. Excellent agreement is found between HRDI measured winds and winds observed with radars and rockets. In addition, the sensitivity of HRDI to migrating tides and other large scale waves is demonstrated. C1 UNIV ILLINOIS,DEPT ELECT & COMP ENGN,URBANA,IL 61801. WALLOPS FLIGHT FACIL,GODDARD SPACE FLIGHT CTR,WALLOPS ISL,VA 23337. UNIV ADELAIDE,DEPT PHYS & MATH PHYS,ADELAIDE,SA 5001,AUSTRALIA. RP BURRAGE, MD (reprint author), UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109, USA. RI Wu, Dong/D-5375-2012 NR 11 TC 33 Z9 33 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1259 EP 1262 DI 10.1029/93GL01108 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800038 ER PT J AU DOUGLASS, A ROOD, R WATERS, J FROIDEVAUX, L READ, W ELSON, L GELLER, M CHI, Y CERNIGLIA, M STEENROD, S AF DOUGLASS, A ROOD, R WATERS, J FROIDEVAUX, L READ, W ELSON, L GELLER, M CHI, Y CERNIGLIA, M STEENROD, S TI A 3D SIMULATION OF THE EARLY WINTER DISTRIBUTION OF REACTIVE CHLORINE IN THE NORTH POLAR VORTEX SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Early in December 1991, high values of ClO are seen by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite at latitudes south of areas of temperatures cold enough to form polar stratospheric clouds (PSC's). A three dimensional simulation shows that the heterogeneous conversion of chlorine reservoirs to reactive chlorine on the surfaces of PSC's (processing) takes place at high latitudes. Often the ''processed'' air must be transported to lower latitudes, where the reactive chlorine is photochemically converted to ClO, to be observed by MLS. In this simulation, one incidence of cold temperatures is associated with an anticyclone, and a second with a cyclone. The transport of processed air associated with the anticyclone is marked by shearing; a decrease in the maximum of the processed air is accompanied by growth of the area influenced by the processing. In contrast, the air processed in the cyclonic event spreads more slowly. This shows that transport and shearing is a crucial element to the evolution of reactive chlorine associated with a processing event. In particular, transport and shearing, as well as photochemical processes, can cause variations in observed ClO. C1 JET PROP LAB,PASADENA,CA 91109. SUNY,STONY BROOK,NY 11794. APPL RES CORP,LANDOVER,MD 20785. RP DOUGLASS, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Douglass, Anne/D-4655-2012; Steenrod, Stephen/H-2218-2012; Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 NR 10 TC 20 Z9 20 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1271 EP 1274 DI 10.1029/93GL01586 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800041 ER PT J AU MANNEY, GL ZUREK, RW AF MANNEY, GL ZUREK, RW TI INTERHEMISPHERIC COMPARISON OF THE DEVELOPMENT OF THE STRATOSPHERIC POLAR VORTEX DURING FALL - A 3-DIMENSIONAL PERSPECTIVE FOR 1991-1992 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The development of the stratospheric polar vortex during fall and early winter in the Northern Hemisphere (NH) during 1991-1992, and the Southern Hemisphere (SH) during 1992 is examined using National Meteomlogical Center data. Compared to the NH, the polar vortex in the SH developed with less variability on short time scales, deepened more rapidly and continued to expand well into winter. Daily minimum temperatures in the lower stratosphere were lowest at equivalent seasonal dates in both hemispheres, but values below the condensation temperatures of polar stratospheric clouds occurred earlier, persisted much longer, and occupied a larger volume of air in the SH. These interhemispheric meteorological differences can account for some of the key features of the chlorine monoxide distributions observed by the Microwave Limb Sounder on the Upper Atmosphere Research Satellite. RP MANNEY, GL (reprint author), JET PROP LAB,MAILSTOP 183-701,PASADENA,CA 91109, USA. NR 13 TC 33 Z9 33 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1275 EP 1278 DI 10.1029/93GL01111 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800042 ER PT J AU MANNEY, GL FROIDEVAUX, L WATERS, JW ELSON, LS FISHBEIN, EF ZUREK, RW HARWOOD, RS LAHOZ, WA AF MANNEY, GL FROIDEVAUX, L WATERS, JW ELSON, LS FISHBEIN, EF ZUREK, RW HARWOOD, RS LAHOZ, WA TI THE EVOLUTION OF OZONE OBSERVED BY UARS MLS IN THE 1992 LATE WINTER SOUTHERN POLAR VORTEX SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TRANSPORT AB The evolution of ozone (O3) observed by the Microwave Limb Sounder on board the Upper Atmosphere Research Satellite is described for 14 Aug through 20 Sep 1992, in relation to the polar vortex. The development of an ozone hole is observed in column O3, and a corresponding decrease is seen in O3 mixing ratio in the polar lower stratosphere, consistent with chemical destruction. The observations also suggest that poleward transport associated with episodes of strong planetary wave activity is important in increasing O3 in the mid-stratosphere. C1 UNIV EDINBURGH,DEPT METEOROL,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. RP MANNEY, GL (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 10 TC 37 Z9 37 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1279 EP 1282 DI 10.1029/93GL01345 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800043 ER PT J AU HERVIG, ME RUSSELL, JM GORDLEY, LL PARK, JH DRAYSON, SR AF HERVIG, ME RUSSELL, JM GORDLEY, LL PARK, JH DRAYSON, SR TI OBSERVATIONS OF AEROSOL BY THE HALOE EXPERIMENT ONBOARD UARS - A PRELIMINARY VALIDATION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SULFURIC-ACID; STRATOSPHERE; GROWTH AB The HALOE experiment measures vertical profiles of aerosol extinction at five infrared wavelengths. Four of these observations are obtained using a combination of gas filter and broadband radiometer measurements in bands of HF, HCl, CH4, and NO centered at wavelengths of 2.45, 3.40, 3.45, and 5.26 mum, respectively. The fifth is obtained using broadband radiometer measurements Of CO2 transmission at 2.79 mum. Error analysis shows that the random extinction uncertainties are generally less than 10% in the aerosol layer, increasing to over 20% at the profile tops. HALOE spectral extinction measurements are shown to be consistent with predicted spectral extinction for stratospheric sulfate aerosol. Profile comparisons between HALOE and independent sources result in generally good agreement in the shape and magnitude of peak extinction and the altitude where the peak extinction occurs. In addition, global aerosol distributions obtained from the data are consistent with expected aerosol morphology. Although the validation is preliminary, the HALOE aerosol data appear to be of excellent quality and to accurately represent optical characteristics and distribution of the aerosols. C1 UNIV MICHIGAN,ANN ARBOR,MI 48105. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP HERVIG, ME (reprint author), G&A TECH SOFTWARE,28 RES DR,HAMPTON,VA 23666, USA. NR 12 TC 36 Z9 37 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1291 EP 1294 DI 10.1029/93GL00829 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800046 ER PT J AU READ, WG FROIDEVAUX, L WATERS, JW AF READ, WG FROIDEVAUX, L WATERS, JW TI MICROWAVE LIMB SOUNDER MEASUREMENT OF STRATOSPHERIC SO2 FROM THE MT-PINATUBO VOLCANO SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The Microwave Limb Sounder (MLS) experiment on the Upper Atmosphere Research Satellite (UARS) began atmospheric measurements oil September 19,1991. Residual SO2 from the Pinatubo eruption was detected immediately after instrument activation. The SO2 was located in a tropical band with peak mixing ratios of approximately 15 ppbv near 26 km altitude. The observed decay of SO2 has provided an estimate of the OH concentration in the plume. RP READ, WG (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 22 TC 123 Z9 123 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1299 EP 1302 DI 10.1029/93GL00831 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800048 ER PT J AU SHEPHERD, GG THUILLIER, G SOLHEIM, BH CHANDRA, S COGGER, LL DUBOIN, ML EVANS, WFJ GATTINGER, RL GAULT, WA HERSE, M HAUCHECORNE, A LATHUILLIERE, C LLEWELLYN, EJ LOWE, RP TEITELBAUM, H VIAL, F AF SHEPHERD, GG THUILLIER, G SOLHEIM, BH CHANDRA, S COGGER, LL DUBOIN, ML EVANS, WFJ GATTINGER, RL GAULT, WA HERSE, M HAUCHECORNE, A LATHUILLIERE, C LLEWELLYN, EJ LOWE, RP TEITELBAUM, H VIAL, F TI LONGITUDINAL STRUCTURE IN ATOMIC OXYGEN CONCENTRATIONS OBSERVED WITH WINDII ON UARS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GRAVITY-WAVES; AIRGLOW AB WINDII, the Wind Imaging Interferometer on the Upper Atmosphere Research Satellite, began atmospheric observations on September 28, 1991 and since then has been collecting data on winds, temperatures and emissions rates from atomic, molecular and ionized oxygen species, as well as hydroxyl. The validation of winds and temperatures is not yet complete, and scientific interpretation has barely begun, but the dominant characteristic of these data so far is the remarkable structure in the emission rate from the excited species produced by the recombination of atomic oxygen. The latitudinal and temporal variability has been noted before by many others. In this preliminary report on WINDII results we draw attention to the dramatic longitudinal variations of planetary wave character in atomic oxygen concentration, as reflected in the OI 557.7 nm emission, and to similar variations seen in the Meinel hydroxyl band emission. C1 CNRS,SERV AERON,F-91370 VERRIERES BUISSON,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV CALGARY,DEPT PHYS,CALGARY T2N 1N4,ALBERTA,CANADA. CNRS,CNET,CRPE,F-92131 ISSY MOULINEAUX,FRANCE. TRENT UNIV,FAC ENVIRONM STUDIES,PETERBOROUGH K9J 7B8,ONTARIO,CANADA. NATL RES COUNCIL CANADA,OTTAWA K1A 0R6,ONTARIO,CANADA. CEPHAG,F-38402 ST MARTIN DHERES,FRANCE. UNIV SASKATCHEWAN,INST SPACE & ATMOSPHER STUDIES,SASKATOON S7N 0W0,SASKATCHEWAN,CANADA. UNIV WESTERN ONTARIO,DEPT PHYS,LONDON N6A 3K7,ONTARIO,CANADA. ECOLE POLYTECH,METEOROL DYNAM LAB,F-91128 PALAISEAU,FRANCE. RP SHEPHERD, GG (reprint author), YORK UNIV,CTR RES EARTH & SPACE SCI,INST SPACE & TERR SCI,N YORK M3J 1P3,ONTARIO,CANADA. RI Hauchecorne, Alain/A-8489-2013 NR 18 TC 47 Z9 47 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1303 EP 1306 DI 10.1029/93GL01105 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800049 ER PT J AU LUO, MZ RUSSELL, JM CICERONE, RJ GORDLEY, LL AF LUO, MZ RUSSELL, JM CICERONE, RJ GORDLEY, LL TI ANALYSIS OF SELECTED NITRIC-OXIDE OBSERVATIONS IN THE LOWER THERMOSPHERE BY HALOE ON UARS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERE EXPLORER; AURORAL STORM; E-REGION; LATITUDES AB Measurements of nitric oxide mixing ratios have been made by the Halogen Occultation Experiment on the Upper Atmosphere Research Satellite over an altitude range extending from 15 to 130 km on every spacecraft sunrise and sunset event with the exception of about 8% downtime. Selected NO profiles from the first few months of observations were examined with emphasis on the relation between geomagnetic disturbances and enhanced NO in the lower thermosphere. During a large geomagnetic storm on November 8-9, 1991, HALOE obtained 15 NO sunrise profiles along the approximately 50-degrees-N latitude circle. A factor of 3 increase in NO mixing ratio above approximately 115 km at this latitude and a one to two day decay time were observed. The measured NO longitude/altitude cross section on this day shows a longitudinal asymmetry in the NO distribution with a maximum near the geomagnetic pole. From approximately one month's data, a latitude/altitude cross section of zonal mean NO mixing ratio was calculated. An example of such cross sections demonstrates a strong positive correlation between geomagnetic activity and thermospheric NO globally. This auroral forcing has a larger effect on increasing NO at high latitude than at low latitude. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. GATS INC,HAMPTON,VA 23681. RP LUO, MZ (reprint author), UNIV CALIF IRVINE,DEPT GEOSCI,IRVINE,CA 92717, USA. NR 19 TC 14 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 18 PY 1993 VL 20 IS 12 BP 1307 EP 1310 DI 10.1029/93GL01109 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LL288 UT WOS:A1993LL28800050 ER PT J AU FICHTEL, CE AF FICHTEL, CE TI RECENT RESULTS FROM THE COMPTON GAMMA-RAY OBSERVATORY SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID COSMIC-RAYS; RADIATION; GEMINGA; GALAXY RP FICHTEL, CE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 51 TC 2 Z9 2 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 136 EP 147 DI 10.1111/j.1749-6632.1993.tb43892.x PG 12 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500012 PM 26469417 ER PT J AU MUSHOTZKY, R AF MUSHOTZKY, R TI IMPLICATIONS OF RECENT CLUSTER OBSERVATIONS FOR COSMOLOGY SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID X-RAY; COMA CLUSTER; DARK MATTER; GALAXIES; MASS; MORPHOLOGY RP MUSHOTZKY, R (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. NR 46 TC 12 Z9 12 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PD JUN 15 PY 1993 VL 688 BP 184 EP 194 PG 11 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500015 ER PT J AU HARDING, AK AF HARDING, AK TI GAMMA-RAY EMISSION FROM PULSARS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID POLAR CAPS; GAPS; RADIATION RP HARDING, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Harding, Alice/D-3160-2012 NR 22 TC 2 Z9 2 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 573 EP 580 DI 10.1111/j.1749-6632.1993.tb43939.x PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500059 PM 26469464 ER PT J AU OZERNOY, LM AF OZERNOY, LM TI THE GALACTIC-CENTER PUTATIVE BLACK-HOLE - RECENT MASS EVALUATIONS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID SAGITTARIUS-A C1 GEORGE MASON UNIV,INST COMPUTAT SCI & INFORMAT,FAIRFAX,VA 22030. RP OZERNOY, LM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,USRA,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 12 TC 5 Z9 5 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 596 EP 597 DI 10.1111/j.1749-6632.1993.tb43942.x PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500062 PM 26469467 ER PT J AU SCHRAMM, DN AF SCHRAMM, DN TI SUMMARY OF RECENT DEVELOPMENTS IN PRIMORDIAL NUCLEOSYNTHESIS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID BIG-BANG NUCLEOSYNTHESIS; NEUTRON LIFETIME; EARLY UNIVERSE; HALO-STARS; LITHIUM; CONSTRAINTS; ABUNDANCES; COSMOLOGY; ORIGIN; BERYLLIUM AB This paper summarizes the recent observational and theoretical results on Big Bang Nucleosynthesis. In particular, it is shown that the new Pop II Li-6 results strongly support the argument that the Spite Plateau lithium is a good estimate of the primordial value. The Li-6 is consistent with the Be and Be found in Pop II stars, assuming those elements are cosmic ray produced. The HST 2D value tightens the 2D arguments and the observation of the He-4 in planetary nebula strengthens the He-3 + 2D argument as a lower bound on OMEGA(b). The new low metalicity He-4 determinations slightly raise the best primordial He-4 number and thus make a better fit and avoid a potential problem. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in OMEGA(b) are possible vis-a-vis the homogeneous model; hence, the robustness of OMEGA(b) approximately 0.05 is now apparent. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. OMEGA(b) approximately 1 seems to be definitely excluded, so, if OMEGA = 1, as some recent observations may hint, then non-baryonic dark matter is required. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP SCHRAMM, DN (reprint author), UNIV CHICAGO,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 73 TC 1 Z9 1 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 776 EP 791 DI 10.1111/j.1749-6632.1993.tb43971.x PG 16 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500091 PM 26469496 ER PT J AU BENSADOUN, M BERSANELLI, M BONELLI, G DEAMICI, G KOGUT, A LEVIN, S LIMON, M SIRONI, G SMOOT, G VINJE, W AF BENSADOUN, M BERSANELLI, M BONELLI, G DEAMICI, G KOGUT, A LEVIN, S LIMON, M SIRONI, G SMOOT, G VINJE, W TI LOW-FREQUENCY MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND SPECTRUM SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID TEMPERATURE; GHZ; WAVELENGTH; RADIATION; EMISSION; POLE C1 IFCTR,I-20133 MILAN,ITALY. UNIV CALIF BERKELEY,LBL,BERKELEY,CA 94720. JET PROP LAB,PASADENA,CA 91109. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. NASA,GODDARD SPACE FLIGHT CTR,GSFC,USRA,GREENBELT,MD 20771. RP BENSADOUN, M (reprint author), UNIV CALIF BERKELEY,SSL,BERKELEY,CA 94720, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 792 EP 794 DI 10.1111/j.1749-6632.1993.tb43972.x PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500092 PM 26469497 ER PT J AU GANGA, K CHENG, E MEYER, S PAGE, L AF GANGA, K CHENG, E MEYER, S PAGE, L TI CROSS-CORRELATION BETWEEN THE 170 GHZ SURVEY MAP AND THE COBE DIFFERENTIAL MICROWAVE RADIOMETER 1ST-YEAR MAPS SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID BACKGROUND ANISOTROPY; MILLIMETER C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP GANGA, K (reprint author), PRINCETON UNIV,JOSEPH HENRY LABS,JADWIN HALL,PRINCETON,NJ 08544, USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 795 EP 797 DI 10.1111/j.1749-6632.1993.tb43973.x PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500093 PM 26469498 ER PT J AU PUCHALLA, J CHENG, E COTTINGHAM, D FIXSEN, D GENTIEU, EP INMAN, C KOWITT, M MEYER, S PAGE, L SILVERBERG, R AF PUCHALLA, J CHENG, E COTTINGHAM, D FIXSEN, D GENTIEU, EP INMAN, C KOWITT, M MEYER, S PAGE, L SILVERBERG, R TI PRELIMINARY-RESULTS OF THE MEDIUM-SCALE ANISOTROPY MEASUREMENT SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV SPACE RES ASSOC,NASA,GSFC,GREENBELT,MD 20771. APPL RES CORP,NASA,GSFC,GREENBELT,MD 20771. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. RP PUCHALLA, J (reprint author), MIT,ROOM 20B-145,CAMBRIDGE,MA 02139, USA. NR 1 TC 2 Z9 2 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 801 EP 803 DI 10.1111/j.1749-6632.1993.tb43975.x PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500095 PM 26469500 ER PT J AU STEBBINS, A AF STEBBINS, A TI ON THE MEANING OF DELTA-T/T SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID UNIVERSE RP STEBBINS, A (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 824 EP 826 DI 10.1111/j.1749-6632.1993.tb43982.x PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500102 PM 26469507 ER PT J AU KASHLINSKY, A AF KASHLINSKY, A TI LARGE-SCALE DATA, MICROWAVE BACKGROUND AND INFLATION SO ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article ID DARK MATTER; ANISOTROPY RP KASHLINSKY, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 685,GREENBELT,MD 20771, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0077-8923 J9 ANN NY ACAD SCI JI Ann. N.Y. Acad. Sci. PD JUN 15 PY 1993 VL 688 BP 830 EP 832 DI 10.1111/j.1749-6632.1993.tb43984.x PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LM125 UT WOS:A1993LM12500104 PM 26469509 ER PT J AU JAYATILAKA, D LEE, TJ AF JAYATILAKA, D LEE, TJ TI OPEN-SHELL COUPLED-CLUSTER THEORY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID QUADRATIC CONFIGURATION-INTERACTION; EFFICIENT REFORMULATION; ELECTRON CORRELATION; CCSD; EQUATIONS; SINGLES; MODEL AB An efficient formulation of our recently proposed [Chem. Phys. Lett. 199, 211 (1992)] open-shell singles and doubles coupled-cluster (OCCSD) method is presented. This formulation is in terms of spatial orbital one- and two-electron integrals. Our new OCCSD method is based on ''symmetric spin orbitals'' and is thus symmetric (or antisymmetric) in the spin indices. It therefore contains about half the number of independent parameters in the coupled-cluster wave function compared to other open-shell CCSD methods. It is shown that the formulation presented here contains less than half the number of n6 steps (where n is the number of molecular orbitals) of other recently proposed open-shell CCSD methods. A new approach by which amplitudes in our method may be compared with amplitudes in a previous OCCSD method is examined. RP JAYATILAKA, D (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Jayatilaka, Dylan/B-3498-2012; Lee, Timothy/K-2838-2012 OI Jayatilaka, Dylan/0000-0002-3349-5834; NR 30 TC 121 Z9 121 U1 4 U2 13 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1993 VL 98 IS 12 BP 9734 EP 9747 DI 10.1063/1.464352 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LG101 UT WOS:A1993LG10100053 ER PT J AU LIU, AK HAKKINEN, S PENG, CY AF LIU, AK HAKKINEN, S PENG, CY TI WAVE EFFECTS ON OCEAN-ICE INTERACTION IN THE MARGINAL ICE-ZONE SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SYNTHETIC APERTURE RADAR; SEA ICE; MESOSCALE EDDIES; EDGE; MODEL; WIND; PROPAGATION; LIMEX; FIELD; SWELL AB The effects of wave train on ice-ocean interaction in the marginal ice zone are studied through numerical modeling. A coupled two-dimensional ice-ocean model has been developed to include wave effects and wind stress for the predictions of ice edge dynamics. The sea ice model is coupled to the reduced-gravity ocean model through interfacial stresses. The main dynamic balance in the ice momentum is between water-ice stress, wind stress, and wave radiation stresses. By considering the exchange of momentum between waves and ice pack through radiation stress for decaying waves, a parametric study of the effects of wave stress and wind stress on ice edge dynamics has been performed. The numerical results show significant effects from wave action. The ice edge is sharper, and ice edge meanders form in the marginal ice zone owing to forcing by wave action and refraction of swell system after a couple of days. Upwelling at the ice edge and eddy formation can be enhanced by the nonlinear effects of wave action; wave action sharpens the ice edge and can produce ice meandering, which enhances local Ekman pumping and pycnocline anomalies. The resulting ice concentration, pycnocline changes, and flow velocity field are shown to be consistent with previous observations. C1 SCI SYST & APPLICAT INC,LANHAM,MD 20706. RP LIU, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,HYDROSPHER PROC LAB,CODE 971,GREENBELT,MD 20771, USA. RI Hakkinen, Sirpa/E-1461-2012 NR 37 TC 15 Z9 15 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1993 VL 98 IS C6 BP 10025 EP 10036 DI 10.1029/93JC00653 PG 12 WC Oceanography SC Oceanography GA LJ209 UT WOS:A1993LJ20900004 ER PT J AU HIGGINS, RW SCHUBERT, SD AF HIGGINS, RW SCHUBERT, SD TI LOW-FREQUENCY SYNOPTIC-EDDY ACTIVITY IN THE PACIFIC STORM TRACK SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID HEMISPHERE WINTERTIME CIRCULATION; TIME-MEAN FLOW; EXTRATROPICAL RESPONSE; GENERAL-CIRCULATION; SOUTHERN-HEMISPHERE; BAROCLINIC WAVES; TRANSIENT EDDIES; LIFE-CYCLES; EL-NINO; PROPAGATION AB The nature of low-frequency variations in synoptic-eddy activity over the North Pacific is examined in a general circulation model (GCM). A comparison with observations reveals that the GCM produces realistic time mean and low-frequency synoptic-eddy forcing of the 200-mb zonal wind. In the time mean, this forcing, which is computed as the divergence of the extended Eliassen-Palm (E-P) flux, shows an east-west dipole structure that tends to reduce the zonal wind over the western North Pacific and tends to enhance it to the east. This structure is consistent with the general picture of the life cycle of baroclinic waves, which show strong upward and eastward propagation in the western and central Pacific and meridional propagation to the east. The western and central Pacific synoptic-eddy forcing is dominated by the convergence of the baroclinic component of the E-P flux divergence, while over the eastern Pacific the divergence of the barotropic component is important. The dominant component of the low-frequency ''envelope'' (periods > 10 days) of synoptic-eddy forcing, computed as the first empirical orthogonal function (EOF) modulates the time mean synoptic-eddy forcing. This modulation is associated with low-frequency changes in the intensity of the synoptic-eddy activity and is only weakly tied to fluctuations in the low-frequency flow. Composites of the hemispheric distribution of synoptic-eddy forcing in the GCM, based on the extremes of the dominant Pacific EOF, show a seesaw behavior with enhanced eddy forcing in the North Pacific basin associated with suppressed forcing in the North Atlantic basin, and vice versa. The link between the Pacific and the Atlantic basins appears to be due to the presence of eastward-traveling baroclinic wave packets that travel around the globe with a period of about 10 days. Some evidence is found for a similar behavior in the observations. RP NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, CODE 9103, GREENBELT, MD 20771 USA. NR 28 TC 10 Z9 12 U1 0 U2 2 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 15 PY 1993 VL 50 IS 12 BP 1672 EP 1690 DI 10.1175/1520-0469(1993)050<1672:LFSEAI>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LJ887 UT WOS:A1993LJ88700005 ER PT J AU SINGH, J SWANK, J AF SINGH, J SWANK, J TI X-RAY OBSERVATIONS OF EX HYDRAE WITH THE EINSTEIN SOLID-STATE SPECTROMETER SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ACCRETION, ACCRETION DISKS; BINARIES, ECLIPSING; STARS, INDIVIDUAL, EX HYA; STARS, MAGNETIC FIELDS; X-RAYS, STARS ID HYA; EMISSION; LIGHT AB Einstein SSS X-ray observations of the eclipsing intermediate polar EX Hya are presented. The SSS data have a better resolution at energies extending below 2 keV than do the EXOSAT data. These data reveal the presence of a soft component with a temperature of approximately 0.74 keV The phase-resolved data can be fitted to a model of two-temperature thermal plasma with a single absorber, with the result that only the normalization varies with phase. This suggests that part of the soft component might become occulted at minimum. If we assume that the reduction in the flux occurs due to the photoelectric absorption, we find that a high-density material covering only approximately 40 per cent of the emission can fit the data equally well. The EXOSAT and Ginga data of this source favour the accretion curtain model rather than the occultation model. We modify the accretion curtain model by assuming that the modulation is caused by an absorber which partially covers the accreting column at the minimum of the 67-min pulse. An emission line at 1.72 keV is present in the data. The equivalent width of this line varies in phase with the continuum. We associate this line with Si fluorescence. RP SINGH, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 666,GREENBELT,MD 20771, USA. NR 16 TC 17 Z9 17 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 15 PY 1993 VL 262 IS 4 BP 1000 EP 1006 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LH525 UT WOS:A1993LH52500021 ER PT J AU MCKENZIE, RL AF MCKENZIE, RL TI RAYLEIGH REJECTION FILTERS FOR 193-NM ARF LASER RAMAN-SPECTROSCOPY SO OPTICS LETTERS LA English DT Article AB Selected organic absorbers and their solvents are evaluated as spectral filters for the rejection of 193-nm Rayleigh light associated with the use of an ArF excimer laser for Raman spectroscopy. A simply constructed filter cell filled with 0.5% acetone in water and an optical path of 7 mm is shown effectively to eliminate stray Rayleigh light underlying the Raman spectrum from air while transmitting 60% of the Raman light scattered by O2. RP MCKENZIE, RL (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 9 TC 5 Z9 5 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 1993 VL 18 IS 12 BP 995 EP 997 DI 10.1364/OL.18.000995 PG 3 WC Optics SC Optics GA LF889 UT WOS:A1993LF88900021 PM 19823270 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI AN ACCURATE DETERMINATION OF THE HO2 HEAT OF FORMATION SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BOND-DISSOCIATION ENERGIES; HYDROGEN-PEROXIDE; REDOX POTENTIALS; ELECTRON CORRELATION; DELTA-HDBE; H-OO; REEVALUATION; ENTHALPIES; MOLECULES; SURFACE AB The heat of formation of HO2 has been determined using highly accurate ab initio calculations. Our computed value is 3.5 +/- 0.5 kcal/mol at 0 K (or 2.8 +/- 0.5 kcal/mol at 298 K). The accuracy of the current result is estimated on the basis of calibration calculations on H-2, OH, H2O, O2, and H2O2, which are also discussed in this work. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 40 TC 24 Z9 24 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 11 PY 1993 VL 208 IS 3-4 BP 241 EP 246 DI 10.1016/0009-2614(93)89069-T PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LF716 UT WOS:A1993LF71600018 ER PT J AU ATHALE, RA ASTOR, ME YU, J AF ATHALE, RA ASTOR, ME YU, J TI MOSAIC - A SPACE-MULTIPLEXING TECHNIQUE FOR OPTICAL-PROCESSING OF LARGE IMAGES SO APPLIED OPTICS LA English DT Note AB A technique for Fourier processing of images larger than the space-bandwidth products of conventional or smart spatial light modulators and two-dimensional detector arrays is described. The technique involves a spatial combination of subimages displayed on individual spatial light modulators to form a phase-coherent image, which is subsequently processed with Fourier optical techniques. Because of the technique's similarity with the mosaic technique used in art, the processor used is termed an optical MOSAIC processor. The phase accuracy requirements of this system were studied by computer simulation. It was found that phase errors of less than lambda/8 did not degrade the performance of the system and that the system was relatively insensitive to amplitude nonuniformities. Several schemes for implementing the subimage combination are described. Initial experimental results demonstrating the validity of the mosaic concept are also presented. C1 JET PROP LAB, PASADENA, CA 91109 USA. RP ATHALE, RA (reprint author), GEORGE MASON UNIV, DEPT ELECT & COMP ENGN, FAIRFAX, VA 22030 USA. NR 5 TC 0 Z9 0 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 10 PY 1993 VL 32 IS 17 BP 3087 EP 3091 PG 5 WC Optics SC Optics GA LE984 UT WOS:A1993LE98400008 PM 20829917 ER PT J AU THOMPSON, DJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K SCHNEID, EJ SREEKUMAR, P AF THOMPSON, DJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K SCHNEID, EJ SREEKUMAR, P TI GAMMA-RADIATION FROM BLAZAR PKS 0537-441 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, OBSERVATIONS; BL LACERTAE OBJECTS, INDIVIDUAL (PKS 0537-441) ID RADIO-SOURCES; MULTIFREQUENCY OBSERVATIONS; TELESCOPE AB The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) observed high-energy gamma rays (E greater-than-or-equal-to 50 MeV) from PKS 0537-441 during observations in 1991 July-August. Upper limits from later EGRET observations suggest time variability. C1 MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. HAMPDEN SYDNEY COLL,DEPT PHYS,HAMPDEN SYDNEY,VA 23943. COMPTON OBSERV SCI SUPPORT CTR,GREENBELT,MD. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. STANFORD UNIV,WW HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. RP THOMPSON, DJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 36 TC 33 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1993 VL 410 IS 1 BP 87 EP 89 DI 10.1086/172727 PN 1 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LE330 UT WOS:A1993LE33000010 ER PT J AU ABERG, J AF ABERG, J TI THE WAY TO GO SO EDN LA English DT Letter RP ABERG, J (reprint author), NASA,HUNTSVILLE,AL, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CAHNERS-DENVER PUBLISHING CO PI HIGHLANDS RANCH PA 8773 S RIDGELINE BLVD, HIGHLANDS RANCH, CO 80126-2329 SN 0012-7515 J9 EDN JI EDN PD JUN 10 PY 1993 VL 38 IS 12 BP 28 EP 28 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA LH236 UT WOS:A1993LH23600007 ER PT J AU FAHEY, DW KAWA, SR WOODBRIDGE, EL TIN, P WILSON, JC JONSSON, HH DYE, JE BAUMGARDNER, D BORRMANN, S TOOHEY, DW AVALLONE, LM PROFFITT, MH MARGITAN, J LOEWENSTEIN, M PODOLSKE, JR SALAWITCH, RJ WOFSY, SC KO, MKW ANDERSON, DE SCHOEBERL, MR CHAN, KR AF FAHEY, DW KAWA, SR WOODBRIDGE, EL TIN, P WILSON, JC JONSSON, HH DYE, JE BAUMGARDNER, D BORRMANN, S TOOHEY, DW AVALLONE, LM PROFFITT, MH MARGITAN, J LOEWENSTEIN, M PODOLSKE, JR SALAWITCH, RJ WOFSY, SC KO, MKW ANDERSON, DE SCHOEBERL, MR CHAN, KR TI INSITU MEASUREMENTS CONSTRAINING THE ROLE OF SULFATE AEROSOLS IN MIDLATITUDE OZONE DEPLETION SO NATURE LA English DT Article ID HIGH-ALTITUDE AIRCRAFT; HETEROGENEOUS CHEMISTRY; SULFATE AEROSOLS; ER-2 AIRCRAFT; STRATOSPHERE; NITROGEN; VORTEX; HOLE; N2O5; CLO AB In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes. C1 UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. UNIV DENVER,DEPT ENGN,DENVER,CO 80208. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. UNIV CALIF IRVINE,DEPT GEOSCI,IRVINE,CA 92717. HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138. JET PROP LAB,PASADENA,CA 91109. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. HARVARD UNIV,DEPT EARTH & PLANETARY SCI,CAMBRIDGE,MA 02138. ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP FAHEY, DW (reprint author), NOAA,AERON LAB,BOULDER,CO 80303, USA. RI Salawitch, Ross/B-4605-2009; Borrmann, Stephan/E-3868-2010; Toohey, Darin/A-4267-2008; Kawa, Stephan/E-9040-2012; Ko, Malcolm/D-5898-2015; Fahey, David/G-4499-2013 OI Salawitch, Ross/0000-0001-8597-5832; Toohey, Darin/0000-0003-2853-1068; Fahey, David/0000-0003-1720-0634 NR 51 TC 208 Z9 211 U1 3 U2 23 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 10 PY 1993 VL 363 IS 6429 BP 509 EP 514 DI 10.1038/363509a0 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LF939 UT WOS:A1993LF93900039 ER PT J AU CLEMEN, LL DEVATY, RP MACMILLAN, MF YOGANATHAN, M CHOYKE, WJ LARKIN, DJ POWELL, JA EDMOND, JA KONG, HS AF CLEMEN, LL DEVATY, RP MACMILLAN, MF YOGANATHAN, M CHOYKE, WJ LARKIN, DJ POWELL, JA EDMOND, JA KONG, HS TI ALUMINUM ACCEPTOR 4 PARTICLE BOUND EXCITON COMPLEX IN 4H, 6H, AND 3C SIC SO APPLIED PHYSICS LETTERS LA English DT Article AB New lines in the low temperature luminescence spectra of lightly aluminum doped p-type films of 3C, 6H, and 4H SiC are identified and associated with the recombination of a neutral aluminum acceptor four particle bound exciton complex. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CREE RES INC,DURHAM,NC 27713. RP CLEMEN, LL (reprint author), UNIV PITTSBURGH,DEPT PHYS & ASTRON,PITTSBURGH,PA 15260, USA. NR 9 TC 56 Z9 57 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 7 PY 1993 VL 62 IS 23 BP 2953 EP 2955 DI 10.1063/1.109627 PG 3 WC Physics, Applied SC Physics GA LE985 UT WOS:A1993LE98500019 ER PT J AU RAGHAVARAO, R HOEGY, WR SPENCER, NW WHARTON, LE AF RAGHAVARAO, R HOEGY, WR SPENCER, NW WHARTON, LE TI NEUTRAL TEMPERATURE ANOMALY IN THE EQUATORIAL THERMOSPHERE - A SOURCE OF VERTICAL WINDS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ELECTRIC-FIELDS; SPREAD-F; ONSET AB Data obtained from the WATS (Wind and Temperature Spectrometer) instrument on DE-2 (Dynamics Explorer) during high solar activity, show new evidence for the presence of vertical winds of a significant magnitude in the equatorial thermosphere. They reveal a latitudinal structure that can be related to the recently discovered phenomena of the Equatorial Temperature and Wind Anomaly (ETWA). In the local evening hours, the vertical winds usually are downward around the dip equator and collocated with the temperature minimum of ETWA. In general, they are upward at about 24-degrees dip latitude away from the dip equator and are collocated with the ETWA temperature crests. The magnitude of the vertical winds is in the 10-40 m/s range. It is proposed that the temperature and pressure ridges, formed by the excess ion drag on the zonal winds around the two crests and ordered by the relatively lower ion drag at the trough of the well known Equatorial Ionization Anomaly (EIA), drive a new wind system in the meridional plane and that the measured vertical winds form part of this wind system. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY ATMOSPHERES BRANCH CODE 914,GREENBELT,MD 20771. NR 17 TC 56 Z9 57 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 7 PY 1993 VL 20 IS 11 BP 1023 EP 1026 DI 10.1029/93GL01253 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LJ516 UT WOS:A1993LJ51600006 ER PT J AU HOLZSCHEITER, MH BROWN, RE CAMP, JB CORNFORD, S DARLING, T DYER, P GOLDMAN, T HOIBRATEN, S HOSEA, K HUGHES, RJ JARMIE, N KENEFICK, RA KING, NSP LIZON, DC NIETO, MM MIDZOR, MM PARRY, SP ROCHET, J RISTINEN, RA SCHAUER, MM SCHECKER, JA WITTEBORN, FC AF HOLZSCHEITER, MH BROWN, RE CAMP, JB CORNFORD, S DARLING, T DYER, P GOLDMAN, T HOIBRATEN, S HOSEA, K HUGHES, RJ JARMIE, N KENEFICK, RA KING, NSP LIZON, DC NIETO, MM MIDZOR, MM PARRY, SP ROCHET, J RISTINEN, RA SCHAUER, MM SCHECKER, JA WITTEBORN, FC TI TRAPPING OF ANTIPROTONS IN A LARGE PENNING TRAP - PROGRESS TOWARDS A MEASUREMENT OF THE GRAVITATIONAL ACCELERATION OF THE ANTIPROTON SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 2ND BIENNIAL CONF ON LOW-ENERGY ANTIPROTON PHYSICS ( LEAP 92 ) CY SEP 14-19, 1992 CL COURMAYEUR, ITALY SP IST NAZL FIS NUCL, REG AUTONOMA VALLE AOSTA, ASSESSORATO PUBBLICA ISTRUZ AB A measurement of the acceleration of antiprotons in the Earth's gravitational field was proposed to C.E.R.N. in 1986 and was accepted as experiment PS200 for operation at LEAR. In preparation for this experiment up to 50,000 antiprotons have been captured into a large Penning trap and stored for several minutes. This paper describes the experimental technique used and possible improvements in the total number of particles captured and the storage time achieved. We also discuss the current status of the development of the gravity experiment. C1 TEXAS A&M UNIV SYST,COLL STN,TX 77843. UNIV COLORADO,BOULDER,CO 80309. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. CERN,DIV PPE,CH-1211 GENEVA 23,SWITZERLAND. RP HOLZSCHEITER, MH (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 5 TC 21 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD JUN 7 PY 1993 VL 558 BP C709 EP C718 PG 10 WC Physics, Nuclear SC Physics GA LR285 UT WOS:A1993LR28500057 ER PT J AU OHANDLEY, DA ALDRICH, AD AF OHANDLEY, DA ALDRICH, AD TI AN ODYSSEY FOR THE TURN OF THE MILLENNIA SO ACTA ASTRONAUTICA LA English DT Article AB President Bush has called for a return to the Moon and manned expeditions to Mars, implementing a goal of U.S. national space policy to ''expand human presence and activity beyond Earth orbit into the solar system''. These missions will involve Space Station Freedom and robotic spacecraft. They will require advances in technology and will result in significant advances in science. Opportunities for international cooperation are substantial, and the U.S. will seek an exploratory dialogue with other nations on the Space Exploration Initiative, the American term for the expeditions to the Moon and Mars. The strategy for the Moon/Mars initiative has been established. Initial reconnaissance will begin with utilization of robotic space craft, to be followed by emplacement of an outpost. Subsequent activities will consolidate the outpost into a permanent self-reliant settlement. Current efforts in the U.S.A. are expected to lead to the development of two or more significantly different reference mission architectures, while prioritizing the development and demonstration of applicable technologies. These will result from a Synthesis Group activity initiated by NASA in the spring of 1990 to review results from a special ''Outreach Program'' undertaken to secure additional ideas about how best to carry out the President's vision. RP OHANDLEY, DA (reprint author), NASA,OFF AERONAUT EXPLORAT & TECHNOL,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JUN PY 1993 VL 29 IS 6 BP 411 EP 415 DI 10.1016/0094-5765(93)90034-T PG 5 WC Engineering, Aerospace SC Engineering GA LG377 UT WOS:A1993LG37700001 ER PT J AU CRENSHAW, AG FRIDEN, J HARGENS, AR LANG, GH THORNELL, LE AF CRENSHAW, AG FRIDEN, J HARGENS, AR LANG, GH THORNELL, LE TI INCREASED TECHNETIUM UPTAKE IS NOT EQUIVALENT TO MUSCLE NECROSIS - SCINTIGRAPHIC, MORPHOLOGICAL AND INTRAMUSCULAR PRESSURE ANALYSES OF SORE MUSCLES AFTER EXERCISE SO ACTA PHYSIOLOGICA SCANDINAVICA LA English DT Article DE DOWNHILL RUNNING; EXTREME ENDURANCE; FIBER NECROSIS; HUMAN SKELETAL MUSCLE; MITOCHONDRIAL CRYSTALLOIDS; TECHNETIUM PYROPHOSPHATE ID HUMAN SKELETAL-MUSCLE; MITOCHONDRIA; DAMAGE; QUANTITATION; PERFORMANCE; ENDURANCE; INJURIES; ISCHEMIA; GLYCOGEN; TISSUES AB A scintigraphic technique employing technetium pyrophosphate uptake was used to identify the area of skeletal muscle damage in the lower leg of four runners 24 h after an ultramarathon footrace (160 km). Most of the race had been run downhill which incorporated an extensive amount of eccentric work. Soreness was diffuse throughout the posterior region of the lower leg. In order to interpret what increased technetium uptake reflects and to express extreme endurance related damages, a biopsy was taken from the 3-D position of abnormal uptake. In addition, intramuscular pressures were determined in the deep posterior compartment. Scintigraphs revealed increased technetium pyrophosphate uptake in the medial portion of the gastrocnemius muscle. For 3698 fibres analysed, 33 fibres (1%) were necrotic, while a few other fibres were either atrophic or irregular shaped. A cluster of necrotic fibres occurred at the fascicular periphery for one subject and fibre type grouping occurred for another. Ultrastructural analysis revealed Z-line streaming near many capillaries and variously altered subsarcolemmal mitochondria including some with paracrystalline inclusions. The majority of the capillaries included thickened and irregular shaped endothelial cells. Intramuscular pressures of the deep posterior compartment were slightly elevated (12-15 mmHg) for three of the four subjects. Increased technetium uptake following extreme endurance running does not just reflect muscle necrosis but also subtle fibre abnormalities. Collectively, these pathological findings are attributed to relative ischaemia occurring during the race and during pre-race training, whereas, intramuscular pressure elevations associated with muscle soreness are attributed to mechanical stress caused by extensive eccentric work during the race. C1 UMEA UNIV,DEPT HAND SURG,S-90187 UMEA,SWEDEN. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP CRENSHAW, AG (reprint author), UMEA UNIV,DEPT ANAT,S-90187 UMEA,SWEDEN. FU NIADDK NIH HHS [AM-25501] NR 38 TC 27 Z9 27 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0001-6772 J9 ACTA PHYSIOL SCAND JI Acta Physiol. Scand. PD JUN PY 1993 VL 148 IS 2 BP 187 EP 198 DI 10.1111/j.1748-1716.1993.tb09548.x PG 12 WC Physiology SC Physiology GA LF964 UT WOS:A1993LF96400012 PM 8352030 ER PT J AU SMITH, EJ AF SMITH, EJ TI MAGNETIC-FIELDS THROUGHOUT THE HELIOSPHERE SO ADVANCES IN SPACE RESEARCH LA English DT Article ID COSMIC-RAY MODULATION; SOLAR-WIND; CURRENT SHEET; PICKUP IONS; EVOLUTION; 1-AU; PIONEER-11 AB Measurements of the heliospheric magnetic field made over the last several years are surveyed with emphasis on Pioneer 11 observations near 35 AU and Ulysses observations between 1 and 5 AU. The increase in field magnitude at 1 AU near the recent sunspot maximum is also seen at Pioneer 11. Extrapolation of the magnitude and azimuthal component of the field as measured at Pioneer back to 1 AU, assuming the Parker model of a time stationary, spherically symmetric solar wind, leads to values which are systematically lower than the 1 AU measurements. This flux deficit is not confirmed by Voyager measurements and the origin of the discrepancy is unknown. The sector structure continues to be well-defined at large distances. There is evidence at 35 AU of a reduction in the peak-to-peak quasi-periodic (approximately 25 day) variations which are characteristic of the magnetic field structure at lesser radial distances. In 1991, the structure at Pioneer 11 was dominated by a large long-lasting increase associated with the major solar events of March-May. Those events are clearly seen in the Ulysses observations at 2.2 AU and consist of several coronal mass ejections and accompanying shocks. In the latter half of 1991, a sequence of recurrent corotating interaction regions appears with their companion forward and reverse shocks. Contrary to what might have been expected, the March events did not cause a significant restructuring of the heliospheric current sheet, specifically, a change in its inclination. As a consequence, the interval is of particular interest to studies of the solar modulation of galactic cosmic rays and to the effect of global merged interaction regions. The search for ion cyclotron waves resulting from the pick-up of freshly ionized interstellar hydrogen, carried out most recently using Voyager data, continues to be unsuccessful. Thus, there is still no evidence in magnetic field measurements at large distances of the purported interaction between the solar wind and the interstellar medium. RP SMITH, EJ (reprint author), JET PROP LAB,4800 OAK GROVE DR,M-S 169-506,PASADENA,CA 91109, USA. NR 36 TC 40 Z9 40 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 5 EP 14 DI 10.1016/0273-1177(93)90384-N PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800001 ER PT J AU BALOGH, A FORSYTH, RJ AHUJA, A SOUTHWOOD, DJ SMITH, EJ TSURUTANI, BT AF BALOGH, A FORSYTH, RJ AHUJA, A SOUTHWOOD, DJ SMITH, EJ TSURUTANI, BT TI THE INTERPLANETARY MAGNETIC-FIELD FROM 1-AU TO 5-AU - ULYSSES OBSERVATIONS SO ADVANCES IN SPACE RESEARCH LA English DT Article ID AU AB Observations of the Interplanetary Magnetic Field (IMF), carried out from October 1990 to February 1992, during the in-ecliptic phase of the Ulysses mission, are presented in this paper. The observations were made between 1 and 5.4 AU, during a different phase of the solar cycle from previous missions. The large scale reorganisation of the solar coronal fields following the maximum in Solar Cycle 22 generated numerous transient events, causing large scale disturbances in interplanetary space, particularly during the first half of 1991. From about the middle of 1991, solar activity apparently decreased, resulting in fewer transient events, allowing the formation of Corotating Interaction Regions (CIRs) recurring in successive solar rotations. Observations of the IMF reflect this temporal evolution in solar activity. However, the average orientation of the IMF, the observed sector structure and the evolution of the CIRs show that the dynamic interaction of transient events with evolving stream-stream structures in this heliocentric distance range results in significant deviations from the expected IMF topology, even when signature of the transients is less apparent. An overview and preliminary analysis of the observations is provided, with special regard to the probable causes and mechanisms of the observed deviations from the ideal Parker model of the IMF. C1 JET PROP LAB,PASADENA,CA 91109. RP BALOGH, A (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. NR 12 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 15 EP 24 DI 10.1016/0273-1177(93)90385-O PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800002 ER PT J AU BURLAGA, LF AF BURLAGA, LF TI SOLAR-WIND BEHAVIOR THROUGHOUT THE HELIOSPHERE SO ADVANCES IN SPACE RESEARCH LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; LARGE-SCALE FLUCTUATIONS; COSMIC-RAY MODULATION; OUTER HELIOSPHERE; TURBULENCE; GRADIENTS; VOYAGER; PIONEER-11; FRACTALS; 1-AU AB This paper discusses the observations and interpretations of some fundamental phenomena in the outer heliosphere: 1) The Spiral Magnetic Field; 2) The Heliospheric Vortex Street; 3) Merged Interaction Regions; 4) Multifractals; and 5) Intermittent Turbulence. The emphasis is on the Voyager observations in the outer heliosphere. RP BURLAGA, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,EXRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 52 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 27 EP 35 DI 10.1016/0273-1177(93)90386-P PG 9 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800003 ER PT J AU AJELLO, JM PRYOR, WR BARTH, CA HORD, CW SIMMONS, KE AF AJELLO, JM PRYOR, WR BARTH, CA HORD, CW SIMMONS, KE TI SOLAR-WIND LATITUDE VARIATIONS AND MULTIPLE-SCATTERING FROM GALILEO INTERPLANETARY LYMAN-ALPHA OBSERVATIONS SO ADVANCES IN SPACE RESEARCH LA English DT Article AB The Galileo Ultraviolet Spectrometer Experiment (UVS) obtained a map of the celestial sphere from interplanetary Lyman-alpha (IP Lalpha) on 13,14 December 1990 during the Earth1 encounter. The Galileo spacecraft was near the downwind interstellar axis during the encounter and the map view directions filled the downwind hemisphere. The ratio between the observation and a single scattering model is attributed to a direct measurement of the multiple scattering correction required to model IP Lalpha in the inner solar system. Analysis of this data set, referred to as an antisun map, shows that the solar wind charge exchange rate with interplanetary gas is 25% less over the solar poles than in the ecliptic at solar maximum. A model of the interstellar wind based on the antisun map observation exhibits a number density of atomic hydrogen far from the solar system, inside the heliosphere, of 0.16 +/- 0.05 cm-3. C1 UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,BOULDER,CO 80309. RP AJELLO, JM (reprint author), JET PROP LAB,4800 OAK GROVE DR,M-S 169-506,PASADENA,CA 91109, USA. NR 10 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 37 EP 40 DI 10.1016/0273-1177(93)90387-Q PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800004 ER PT J AU PHILLIPS, JL BAME, SJ GOSLING, JT MCCOMAS, DJ GOLDSTEIN, BE BALOGH, A AF PHILLIPS, JL BAME, SJ GOSLING, JT MCCOMAS, DJ GOLDSTEIN, BE BALOGH, A TI SOLAR-WIND THERMAL ELECTRONS FROM 1.15-AU TO 5.34-AU - ULYSSES OBSERVATIONS SO ADVANCES IN SPACE RESEARCH LA English DT Article AB Using unique 3-d velocity space measurements by the Ulysses solar wind plasma experiment from 1. 15 to 5.34 AU, we assess the radial gradient in thermal electron temperature. Until 3.8 AU, the gradient was steeper than previously reported but flatter than adiabatic; after 3.8 AU the gradient flattened. Trends in the observed electron distribution shapes qualitatively support predictions for regulation by Coulomb collisions and by expansion in a spiral IMF. C1 JET PROP LAB,PASADENA,CA 91109. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. RP PHILLIPS, JL (reprint author), LOS ALAMOS NATL LAB,MS-D438,LOS ALAMOS,NM 87545, USA. NR 7 TC 14 Z9 14 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 47 EP 50 DI 10.1016/0273-1177(93)90389-S PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800006 ER PT J AU OSHEROVICH, VA FARRUGIA, CJ BURLAGA, LF AF OSHEROVICH, VA FARRUGIA, CJ BURLAGA, LF TI DYNAMICS OF AGING MAGNETIC CLOUDS SO ADVANCES IN SPACE RESEARCH LA English DT Article ID VOYAGER; AU AB The dynamics of radially expanding magnetic clouds is rigorously analyzed within the framework of ideal MHD. The cloud is modelled as a cylindrically symmetric magnetic flux rope. In the force balance we include the gas pressure gradient and the Lorentz force. Interaction with the ambient solar wind due to expansion of the magnetic cloud is represented by a drag force proportional to the bulk velocity. We consider the self-similar expansion of a polytrope, and reduce the problem to an ordinary non-linear differential equation for the evolution function. Analyzing the asymptotic behaviour of the evolution function, we formulate theoretical expectations for the long-term behaviour of cloud parameters. We focus on the temporal evolution of (i) the magnetic field strength; (ii) the twist of the field lines; (iii) the asymmetry of the total field profile; and (iv) the bulk flow speed. We present data from two magnetic clouds observed at 1 AU and 2 AU, respectively, and find good agreement with theoretical expectations. For a peak magnetic field strength at 1 AU of 25 nT and a polytropic index of 0.5, we find that a magnetic cloud can be distinguished from the background interplanetary field up to a distance of approximately 5 AU. Taking larger magnetic fields (up to 30 nT) and bigger polytropic indices (up to 0.6) this distance can double. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP OSHEROVICH, VA (reprint author), NASA,GSFC,HUGHES STX,4400 FORBES BLVD,LANHAM,MD 20706, USA. NR 15 TC 74 Z9 76 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 57 EP 62 DI 10.1016/0273-1177(93)90391-N PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800008 ER PT J AU GALVIN, AB GLOECKLER, G IPAVICH, FM SHAFER, CM GEISS, J OGILVIE, K AF GALVIN, AB GLOECKLER, G IPAVICH, FM SHAFER, CM GEISS, J OGILVIE, K TI SOLAR-WIND COMPOSITION MEASUREMENTS BY THE ULYSSES SWICS EXPERIMENT DURING TRANSIENT SOLAR-WIND FLOWS SO ADVANCES IN SPACE RESEARCH LA English DT Article AB For the March/April 1991 time period, the alpha/proton abundance ratio, the proton kinetic temperature and speed distributions, and the relative abundance of O+7 to O+6 is determined over each 13-minute duty cycle of the Solar Wind Ion Composition Spectrometer (SWICS) experiment on Ulysses. The ratio O+7/O+6 (as a relative measure of ionization temperature) is shown to be useful in identifying possible coronal mass ejection (CME) events. We report measurements of silicon/oxygen abundance ratios and silicon and oxygen charge state distributions in the solar wind during a CME event and compare these compositions to a ''normal'' solar wind time period. C1 UNIV BERN,INST PHYS,CH-3012 BERN,SWITZERLAND. GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770. RP GALVIN, AB (reprint author), UNIV MARYLAND,DEPT PHYS,COLL PK,MD 20742, USA. RI Galvin, Antoinette/A-6114-2013 NR 11 TC 13 Z9 13 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 75 EP 78 DI 10.1016/0273-1177(93)90393-P PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800010 ER PT J AU SHAFER, CM GLOECKLER, G GALVIN, AB IPAVICH, FM GEISS, J VONSTEIGER, R OGILVIE, K AF SHAFER, CM GLOECKLER, G GALVIN, AB IPAVICH, FM GEISS, J VONSTEIGER, R OGILVIE, K TI SULFUR ABUNDANCES IN THE SOLAR-WIND MEASURED BY SWICS ON ULYSSES SO ADVANCES IN SPACE RESEARCH LA English DT Article AB One of the nine experiments on Ulysses (launched October, 1990), the Solar Wind Ion Composition Spectrometer, utilizes an energy per charge deflection system along with time of flight technology to uniquely determine the mass and mass per charge of solar wind particles. Thus the composition of various solar wind types can be analyzed. Using the SWICS data accumulated during the in-ecliptic phase of the mission, we have determined the sulfur abundance, relative to silicon, in two different types of solar wind: transient and coronal hole associated flows. Sulfur is of extreme interest because it is one of the few elements that lies in the transitional region of the FIP-dependent relative abundance enrichment function, observed for solar energetic particles and some types of solar wind flows. C1 UNIV BERN,INST PHYS,CH-3012 BERN,SWITZERLAND. GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770. RP SHAFER, CM (reprint author), UNIV MARYLAND,DEPT PHYS,COLL PK,MD 20742, USA. RI Galvin, Antoinette/A-6114-2013; Von Steiger, Rudolf/F-6822-2011 OI Von Steiger, Rudolf/0000-0002-3350-0023 NR 9 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 79 EP 82 DI 10.1016/0273-1177(93)90394-Q PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800011 ER PT J AU COOPER, JF BAKER, DN AF COOPER, JF BAKER, DN TI MAGNETOSPHERIC MODELS FOR ELECTRON ACCELERATION AND TRANSPORT IN THE HELIOSPHERE SO ADVANCES IN SPACE RESEARCH LA English DT Article ID RELATIVISTIC ELECTRONS; ORBIT AB Electron transport and acceleration processes in the earth's magnetosphere have correspondences to analogous processes affecting electrons in the solar magnetosphere (i.e., heliosphere). Energetic electrons in planetary magnetospheres and the heliosphere are test particles probing transport and acceleration dynamics with minimal effects on dominant magnetic field configurations. Parallels are discussed relating to electron entry into the magnetospheres from interplanetary and interstellar space, circulatory transport processes, and acceleration by electric fields in boundary regions including shocks and magnetotails. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP COOPER, JF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,NATL SPACE SCI DATA CTR,CODE 633,GREENBELT,MD 20771, USA. RI Cooper, John/D-4709-2012 NR 14 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 103 EP 106 DI 10.1016/0273-1177(93)90398-U PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800015 ER PT J AU DYAL, P AF DYAL, P TI FUTURE OPERATIONS OF PIONEER-10 AND PIONEER-11 SO ADVANCES IN SPACE RESEARCH LA English DT Article ID NITROGEN; OXYGEN AB The Pioneers 10 and 11 spacecraft were launched on 2 March 1972 and 5 April 1973 and are now 53 and 35 AU from the Sun. Pioneer 10 is now the most distant man-made object in our solar system and the in-situ measurements of the gas and dust surrounding the Sun have been obtained for almost two solar sunspot cycles, Plasma analyzer measurements out to 50 AU show that the mean velocity in constant approximately 430 km/sec, the mean density decreases as R-2, and that the terminal shock has not been encountered. The magnetic field is drawn out to form Archimedean spirals in the ecliptic place and dipole-like asymmetry in the polar directions as predicted by the Parker model. Galactic cosmic ray measurements of the intensity and radial gradient indicate a ''modulation boundary'' between 70 to 100 AU from the Sun. All measurements to date indicate that both spacecraft are within the heliosphere and proceeding toward the outer boundary where the modulating effect of solar activity on cosmic ray intensity ceases. RP DYAL, P (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 18 TC 0 Z9 0 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD JUN PY 1993 VL 13 IS 6 BP 267 EP 274 DI 10.1016/0273-1177(93)90419-C PG 8 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA LF448 UT WOS:A1993LF44800036 ER PT J AU RAMAN, G HAILYE, M RICE, EJ AF RAMAN, G HAILYE, M RICE, EJ TI FLIP-FLOP JET NOZZLE EXTENDED TO SUPERSONIC FLOWS SO AIAA JOURNAL LA English DT Article ID TURBULENCE; EVOLUTION; TONES AB An experiment studying a fluidically oscillated rectangular jet flow was conducted. The Mach number was varied over a range from low subsonic to supersonic. Unsteady velocity and pressure measurements were made using hot wires, piezoresistive pressure transducers, and pitot probes. In addition, smoke flow visualization using high-speed photography was used to document the oscillation of the jet. For the subsonic flip-flop jet, it was found that the apparent time-mean widening of the jet was not accompanied by an increase in the mass flux. Fluidically oscillated jets up to a Mach number of about 0.5 have been reported before, but to our knowledge there is no information on fluidically oscillated supersonic jets. It was found that it is possible to extend the operation of these devices to supersonic flows. The streamwise velocity perturbation levels produced by this device were much higher than the perturbation levels that could be produced using conventional excitation sources such as acoustic drivers. In view of this ability to produce high amplitudes, the potential for using a small-scale fluidically oscillated jet as an unsteady excitation source for the control of shear flows in full-scale practical applications seems promising. C1 SVERDRUP TECHNOL INC,BROOKPARK,OH 44142. UNIV MICHIGAN,ANN ARBOR,MI 48103. RP RAMAN, G (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 25 TC 19 Z9 19 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 1993 VL 31 IS 6 BP 1028 EP 1035 DI 10.2514/3.11725 PG 8 WC Engineering, Aerospace SC Engineering GA LH421 UT WOS:A1993LH42100009 ER PT J AU GRAY, CE MEI, C AF GRAY, CE MEI, C TI LARGE-AMPLITUDE FINITE-ELEMENT FLUTTER ANALYSIS OF COMPOSITE PANELS IN HYPERSONIC FLOW SO AIAA JOURNAL LA English DT Article AB A finite element approach is presented for determining the nonlinear flutter characteristics of three-dimensional thin laminated composite panels using the full third-order piston, transverse loading, aerodynamic theory. The unsteady, hypersonic, aerodynamic theory and the von Karman large-deflection plate theory are used to formulate the aeroelasticity problem. Nonlinear flutter analyses are performed to assess the influence of the higher order aerodynamic theory on the structure's limit-cycle amplitude and the dynamic pressure of the flow velocity. A solution procedure is presented to solve the nonlinear panel flutter finite element equations. Nonlinear flutter analyses are performed for different boundary support conditions and for various system parameters: aspect ratio a/b; material orthotropic ratio, lamination angle theta, and number of layers; Mach number M; flow mass density to panel mass density ratio mu/M; dynamic pressure lambda; and maximum deflection to thickness ratio c/h. The large-amplitude panel flutter results for the full third-order piston aerodynamic theory are presented to assess the influence of the nonlinear aerodynamic theory. C1 OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23508. RP GRAY, CE (reprint author), NASA,LANGLEY RES CTR,DIV FACIL ENGN,HAMPTON,VA 23665, USA. NR 36 TC 35 Z9 38 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD JUN PY 1993 VL 31 IS 6 BP 1090 EP 1099 DI 10.2514/3.49051 PG 10 WC Engineering, Aerospace SC Engineering GA LH421 UT WOS:A1993LH42100017 ER PT J AU CHASNOV, JR AF CHASNOV, JR TI DECAYING TURBULENCE IN A PASSIVE MEAN SCALAR GRADIENT SO APPLIED SCIENTIFIC RESEARCH LA English DT Article; Proceedings Paper CT 4TH EUROPEAN TURBULENCE CONF : ADVANCES IN TURBULENCE 4 CY JUN 30-JUL 03, 1992 CL DELFT, NETHERLANDS SP EUROPEAN MECH COMM, CONVEX COMP, HEWLETT PACKARD, SHELL NEDERLAND, AA LAB SYST, CHESS ENGN, CRAY RES EUROPE, DANTEC MEASUREMENT TECHNOL, ERCOFTAC, KLUWER ACAD PUBL DE ISOTROPIC TURBULENCE; PASSIVE SCALAR; MIXING ID ISOTROPIC TURBULENCE AB We consider the generation of passive scalar fluctuations by decaying isotropic turbulence in the presence of a uniform mean scalar gradient. At high Reynolds numbers, two distinct similarity states may be established depending on the form of the energy spectrum at low wavenumber magnitude (k). In the first similarity state characterized by a low wavenumber magnitude energy spectrum proportional to k2, the mean-square scalar fluctuation grows like t4/5, while in the second similarity state characterized by a spectrum proportional to k4, the mean-square scalar fluctuation grows approximately like t4/7. These two high Reynolds number asymptotic similarity states have been subsequently confirmed by large-eddy numerical simulations. As a consequence of the decreasing flow Reynolds number as the turbulence decays, these similarity states do not continue indefinitely. At very long times, a final period of decay of the turbulence occurs, and in this final period, the mean-square scalar fluctuation in the first state continues to grow like t1/2, while that in the second state ultimately decays like t-1/2. C1 LEGI,INST MECAN GRENOBLE,GRENOBLE,FRANCE. RP CHASNOV, JR (reprint author), NASA,AMES RES CTR,CTR TURBULENCE RES,MOFFETT FIELD,CA 94035, USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0003-6994 J9 APPL SCI RES JI Appl. Sci. Res. PD JUN PY 1993 VL 51 IS 1-2 BP 313 EP 317 DI 10.1007/BF01082554 PG 5 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA LM023 UT WOS:A1993LM02300050 ER PT J AU FEKEL, FC BROWNING, JC HENRY, GW MORTON, MD HALL, DS AF FEKEL, FC BROWNING, JC HENRY, GW MORTON, MD HALL, DS TI CHROMOSPHERICALLY ACTIVE STARS .10. SPECTROSCOPY AND PHOTOMETRY OF HD-212280 SO ASTRONOMICAL JOURNAL LA English DT Article ID CA-II H; CLOSE BINARIES; ORBITAL CIRCULARIZATION; SYNCHRONIZATION; SYSTEMS; EVOLUTION; EMISSION AB The system HD 212280 is a chromospherically active double lined spectroscopic binary with an orbital Period of 45.284 days and an eccentricity of 0.50. The spectrum is composite with spectral types of G8 IV and F5-8 V for the components. An estimated inclination of 78-degrees +/- 8-degrees results in masses of 1.7 and 1.4 M. for the G subgiant and mid-F star, respectively. The distance to the system is estimated to be 112 pc. Photometric observations obtained between 1987 November and 1992 June reveal that HD 212280 is a newly identified variable star with a V amplitude of about 0. 15 mag and a mean period of 29.46 days. Our V data were divided into 11 sets and in all but one case two spots were required to fit the data. Lifetimes of 650 days and a minimum of 1350 days have been determined for two of the four spots. These lifetimes are consistent with the results of Hall & Busby [Active Close Binaries, Proceedings of the NATO Advanced Studies Inst. (Kluwer, Dordrecht) (1990)]. The differential rotation coefficient of 0.05 is relatively small. Since the system has an eccentric orbit and one component is significantly evolved, its evolutionary status is of particular interest. The age of the system is about 1.9 X 10(9) years. The G subgiant is rotating slower than pseudosynchronously while the F-type star is rotating faster. The system and its components are compared to the circularization and synchronization time scales of Tassoul & Tassoul (ApJ, 395, 259, 1992). C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. VANDERBILT UNIV,DEPT PHYS & ASTRON,DYER OBSERV,NASHVILLE,TN 37235. RP FEKEL, FC (reprint author), TENNESSEE STATE UNIV,CTR EXCELLENCE INFORMAT SYST,330 10TH AVE,NASHVILLE,TN 37203, USA. NR 44 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1993 VL 105 IS 6 BP 2265 EP 2275 DI 10.1086/116605 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LE322 UT WOS:A1993LE32200027 ER PT J AU NULL, GW OWEN, WM SYNNOTT, SP AF NULL, GW OWEN, WM SYNNOTT, SP TI MASSES AND DENSITIES OF PLUTO AND CHARON SO ASTRONOMICAL JOURNAL LA English DT Article ID GUIDE STAR CATALOG; ATMOSPHERE AB We have analyzed Hubble Space Telescope wide field camera CCD images of Pluto, Charon, and a background star, obtained on seven HST visits over a 3.2 day span in 1991 August, to observe Pluto's barycentric motion and to determine the individual masses and bulk densities of Pluto and Charon. The most fundamental new result was an accurate solution for a previously undetermined parameter, the Charon/Pluto mass ratio q; the new solution is q = 0.0837 +/- 0.0147. Significant accuracy improvements by almost a factor of 2 were obtained for Charon's orbital semimajor axis, a = 19 405 +/- 86 km and the Pluto system mass, M(sys) = (1.401 +/- 0.0 1 9) X 10(8) inverse solar masses. The Pluto and Charon m were M(P) = ( 13.10 +/- 0.24) X 10(24) g and M(C) = ( 1. 10 +/- 0. 18) X 10(24) g, respectively. Computed densities depend strongly on the assumed radius values. Assuming radii determined from mutual event observations by Tholen & Buie [BAAS, 22, 1129 (1990)] then the density of Pluto is rho(p) = 2.13 +/- 0.04 g/cm3 and the density of Charon is rho(C) = 1.30 +/- 0.23 g/cm3. Later analysis of Pluto stellar occultation data [Elliot & Young, AJ, 103, 991 (1992)] indicated that Pluto atmospheric transmission for mutual events and stellar occultations may have a significant effect on determination of the Pluto surface radius R(P). The R(P) value from their ''thermal-gradient'' atmospheric model implies rho(P) = 1.78 +/- 0.06 g/cm3 and the R(P) value from their ''haze'' model implies rho(P) greater-than-or-equal-to 1.90 g/CM3. All these values for rho(P) are significantly higher than the solution value for rho(C). RP NULL, GW (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 35 TC 38 Z9 38 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1993 VL 105 IS 6 BP 2319 EP 2335 DI 10.1086/116610 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LE322 UT WOS:A1993LE32200032 ER PT J AU PIETSCH, W HABERL, F GEHRELS, N PETRE, R AF PIETSCH, W HABERL, F GEHRELS, N PETRE, R TI A ROSAT OBSERVATION OF THE BLACK-HOLE CANDIDATE GRO-J0422+32 SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE X-RAYS, STARS; ACCRETION, ACCRETION DISKS; BLACK HOLE PHYSICS ID VARIABILITY AB We report on a ROSAT HRI observation of the hard transient GRO J0422+32 about 42 days after the start of the outburst. The X-ray position (error radius 6 arcsec) agrees well with the positions of the proposed optical and radio counterparts. In the ROSAT energy band (0.1-2.4 keV) the source showed strong flaring activity; a power spectrum analysis of the photon arival times yields a spectrum with a decrease at frequencies above 0.1 Hz that can be described by a power law with a slope of -1.5. Below 0.1 Hz the spectrum flattens; QPO peaks reported in hard X-rays are confirmed. The integrated rms variability is very high (approximately 40%). The measured 0.1-2.4 keV X-ray flux of 0.3 Crab does not require an additional soft X-ray component in GRO J0422+32, if the source followed the decay trend reported in hard X-rays. The flaring activity and X-ray spectrum of GRO J0422+32 are similar to other black hole candidates in their ''hard' spectral state. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP PIETSCH, W (reprint author), MAX PLANCK INST EXTRATERR PHYS, W-8046 GARCHING, GERMANY. RI Gehrels, Neil/D-2971-2012 NR 26 TC 20 Z9 20 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1993 VL 273 IS 1 BP L11 EP L14 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LF973 UT WOS:A1993LF97300004 ER PT J AU GOLDMAN, I CANUTO, VM AF GOLDMAN, I CANUTO, VM TI COSMIC TURBULENCE REVISITED SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, THEORY; TURBULENCE ID MAGNETIC-FIELDS; UNIVERSE; GENERATION; RADIATION; ENTROPY; ORIGIN AB Primordial cosmic turbulence has been suggested in the past as a mechanism for the formation of large-scale structure in the universe, since it is more efficient than the growth of density perturbations. However, difficulties arose when it was pointed out that (1) the amplitude of the turbulence required to explain the large-scale structure would be in conflict with the observed high degree of isotropy of the microwave background radiation. (2) In addition, following recombination, the turbulence would have become supersonic and produced too large density contrasts on scales of galaxies and clusters of galaxies. (3) Finally, a difficulty of fundamental rather than observational nature: the lack of a specific physical process that could have generated the turbulence in the first place. In this paper, we argue that inflation naturally provides mechanisms for the direct generation of turbulence on the same scales on which density perturbations are formed, thus solving problem 3 above. This calls for a reexamination of the issue of cosmic turbulence since the observational constraints on turbulence (problems 1 and 2, above) could translate into constraints on inflation itself. We find that by the end of inflation, the amplitude of the generated turbulent velocity has been suppressed by a factor greater-than-or-similar-to 10(100) (this result also applies to any turbulence assumed to be part of the initial conditions). Thus, inflation guarantees the absence of turbulence on scales of galaxies and clusters of galaxies and avoids difficulties 1 and 2 above. Alternatively, they constitute an additional support for inflationary cosmology. We show that the density fluctuations generated by inflation can excite longitudinal turbulence after they reenter the Hubble radius at later cosmic epochs (at z greater-than-or-similar-to 27z(eq)). The scales on which this happens are much smaller than those of galaxies. The largest scale corresponds to a present-epoch size of less-than-or-similar-to 6.3 kpc and contains a mass of less-than-or-similar-to 3.6 x 10(4) M.. The smallness of these scales renders the turbulence immune from the observational difficulties 1 and 2 above. Since the generation of this ''secondary'' and ''small-scale'' turbulence seems unavoidable, it should be regarded as yet another ingredient of cosmology. In spite of its small scale, this turbulence can have an important impact on the formation of structure on scales of galaxies and clusters of galaxies. This is so because any part of the turbulence that survived dissipation by the radiative viscosity will become supersonic following the decoupling time. Shocks collisions would lead to large density contrasts on the above small scales. Such an early population of objects of mass less-than-or-equal-to 3.6 x 10(4) M. can serve as a seed that could help the growth of density on the scales of galaxies and clusters of galaxies. C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP GOLDMAN, I (reprint author), TEL AVIV UNIV,SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. NR 36 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP 495 EP 503 DI 10.1086/172681 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC832 UT WOS:A1993LC83200001 ER PT J AU NOLAN, PL ARZOUMANIAN, Z BERTSCH, DL CHIANG, J FICHTEL, CE FIERRO, JM HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NEL, HI NICE, D PINKAU, K ROTHERMEL, H SCHNEID, E SOMMER, M SREEKUMAR, P TAYLOR, JH THOMPSON, DJ AF NOLAN, PL ARZOUMANIAN, Z BERTSCH, DL CHIANG, J FICHTEL, CE FIERRO, JM HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NEL, HI NICE, D PINKAU, K ROTHERMEL, H SCHNEID, E SOMMER, M SREEKUMAR, P TAYLOR, JH THOMPSON, DJ TI OBSERVATIONS OF THE CRAB PULSAR AND NEBULA BY THE EGRET TELESCOPE ON THE COMPTON-GAMMA-RAY-OBSERVATORY SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, OBSERVATIONS; ISM, INDIVIDUAL (CRAB-NEBULA); PULSARS, INDIVIDUAL (CRAB-NEBULA) ID RAPIDLY SPINNING PULSARS; ENERGETIC RADIATION; EMISSION; ENERGIES; MODEL; VELA AB The Crab pulsar and nebula were observed three times in 1991 April to June by the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO): April 23 to May 7, May 16 to 30, and June 8 to 15. The results of analysis of the gamma-ray emission in the energy range from 50 MeV to more than 10 GeV are reported. The observed gamma-ray light curve exhibits two peaks separated in phase by 0.40 +/- 0.02, consistent with previous observations. The total pulsed emission from the Crab pulsar is found to be well represented by a power-law spectrum of the form (4.11 +/- 0.16) x 10(-9)(E/274 MeV)-2.15 +/- 0.04 photons cm-2 s-1 MeV-1 , softer than the spectrum measured by COS B (Clear et al. 1987). The interpulse emission has a harder spectrum than either of the pulses. The evidence for pulsed emission above 5 GeV in the EGRET data is not conclusive. Unpulsed emission in the energy range 50 MeV to 5 GeV was detected, with an indication of a hardening of the unpulsed spectrum above about 1 GeV. There was a significant change in the light curve over the 2 months of these observations, although the shape of the spectrum remained constant. C1 PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. HAMPDEN SYDNEY COLL,HAMPDEN SYDNEY,VA 23943. NASA,GODDARD SPACE FLIGHT CTR,GSFC,COMP SCI CORP,COMPTON OBSERV SCI SUPPORT CTR,GREENBELT,MD 20771. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. UNIV SPACE RES ASSOC,NASA,GSFC,GREENBELT,MD 20771. RP NOLAN, PL (reprint author), STANFORD UNIV,HASAN EXPTL PHYS LAB,STANFORD,CA 94305, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 51 TC 143 Z9 143 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP 697 EP 704 DI 10.1086/172699 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC832 UT WOS:A1993LC83200019 ER PT J AU SRIVASTAVA, KM TSURUTANI, BT GOLDSTEIN, BE AF SRIVASTAVA, KM TSURUTANI, BT GOLDSTEIN, BE TI NUMERICAL-SOLUTION OF WAVE-EQUATIONS FOR THE STABILITY OF THE INNER COMETO-SHEATH SO ASTROPHYSICAL JOURNAL LA English DT Article DE COMETS, GENERAL; MHD ID TOLLMIEN-SCHLICHTING WAVES; BOUNDARY-LAYERS; STREAMWISE VORTICES; HALLEY AB Numerical solution of the MHD wave equations for stability of the cometary sheath determined by the balance between the inward Lorentz body force and the outward ion-neutral drag force is obtained by using a two-point boundary value method. The eigenvalues and the eigenfunctions are obtained numerically by treating the cometary inner sheath as a layer of finite thickness, bounded by the contact surface, i.e, the diamagnetic cavity boundary. The magnetic field structure discovered in the ionosphere of comets Halley and Giacobini-Zinner is found to be unstable. The effects of finite plasma pressure, dissociative recombination, and mass loading due to photoionization are found to be stabilizing but are unable to quench the instability completely. It is also found that the higher the neutral production rate the lesser is the growth rate for the instability. RP SRIVASTAVA, KM (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP 782 EP 789 DI 10.1086/172708 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC832 UT WOS:A1993LC83200028 ER PT J AU JUNG, YD AF JUNG, YD TI SEMICLASSICAL APPROXIMATION FOR ELECTRON-IMPACT EXCITATION OF HYDROGENIC IONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC DATA; ATOMIC PROCESSES AB The threshold behavior of the electron impact excitation cross sections for hydrogenic ions is investigate using the semiclassical approximation with the hyperbolic orbit for the projectile path, rather than the straight line path. The symmetric approximation is applied to modify the ordinary hyperbolic orbit. The modification factor due to the hyperbolic orbit approximation produces the correct energy dependence of the cross section near the excitation threshold. This result is very similar to that of the quantum mechanical case. The semiclassical enhancement factor due to this simple modification corresponds to the Coulomb focusing factor in the Born-Bethe approximation. In the high-energy limit, the semiclassical cross sections approach the Born-Bethe cross sections, with a finite cutoff in the momentum transfer for dipole transitions. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NR 10 TC 38 Z9 38 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP 841 EP 845 DI 10.1086/172714 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC832 UT WOS:A1993LC83200034 ER PT J AU MICHALITSIANOS, AG PEREZ, M SHORE, SN MARAN, SP KAROVSKA, M SONNEBORN, G WEBB, JR BARNES, TG FRUEH, ML OLIVERSEN, RJ STARRFIELD, SG AF MICHALITSIANOS, AG PEREZ, M SHORE, SN MARAN, SP KAROVSKA, M SONNEBORN, G WEBB, JR BARNES, TG FRUEH, ML OLIVERSEN, RJ STARRFIELD, SG TI ULTRAVIOLET CONTINUUM VARIABILITY AND VISUAL FLICKERING IN THE PECULIAR OBJECT MWC-560 SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, EMISSION-LINE, BE; STARS, INDIVIDUAL (MWC-560); TECHNIQUES, PHOTOMETRIC; ULTRAVIOLET, STARS ID CH CYGNI; OUTBURST; STARS AB High-speed U-band photometry of the peculiar emission object MWC 560 obtained with the ground-based instrumentation, and V-band photometry obtained with the International Ultraviolet Explorer (IUE)-Fine Error Sensor (FES) indicates irregular brightness variations are quasi-periodic. Multiple peaks of relative brightness power indicate statistically significant quasi periods exist in a range of 3-35 minutes, that are superposed on slower hourly varying components. We present a preliminary model that explains the minute and hourly time-scale variations in MWC 560 in terms of a velocity-shear instability that arises because a white dwarf magnetosphere impinges on an accretion disk. We also find evidence for Fe II multiplet pseudo-continuum absorption opacity in far-UV spectra of CH Cygni which is also present in MWC 560. Both CH Cyg and MWC 560 may be in an evolutionary stage that is characterized by strong UV continuum opacity which changes significantly during outburst, occurring before they permanently enter the symbiotic nebular emission phase. C1 NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,IUE OBSERV,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,GHRS INSTRUMENT SCI TEAM,GREENBELT,MD 20771. CTR ASTROPHYS,CAMBRIDGE,MA 02138. FLORIDA INT UNIV,DEPT PHYS,MIAMI,FL 33199. UNIV TEXAS,MCDONALD OBSERV,AUSTIN,TX 78712. RP MICHALITSIANOS, AG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 680,GREENBELT,MD 20771, USA. RI Sonneborn, George/D-5255-2012 NR 21 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP L53 EP L56 DI 10.1086/186858 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC834 UT WOS:A1993LC83400006 ER PT J AU SANDFORD, SA ALLAMANDOLA, LJ AF SANDFORD, SA ALLAMANDOLA, LJ TI H-2 IN INTERSTELLAR AND EXTRAGALACTIC ICES - INFRARED CHARACTERISTICS, ULTRAVIOLET PRODUCTION, AND IMPLICATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, INTERSTELLAR, LINES; ISM, MOLECULES; MOLECULAR PROCESSES ID HYDROGEN; CLOUDS; ABSORPTION AB H-2 is the most abundant molecule in the universe. We demonstrate that this molecule may be an important component of interstellar and possibly intergalactic ices, both because it can be formed in situ, within the ices, and because gas phase H-2 can freeze out onto dust grains in some astrophysical environments. The condensation-sublimation and infrared spectral properties of ices containing H-2 are presented. We show that solid H-2 in H2O-rich ices can be detected by an infrared absorption band at 4137 cm-1 (2.417 mum). The surface binding energy of H-2 to H2O ice was measured to be DELTAH(s)/k = 555 +/- 35 K. Surface binding energies can be used to calculate the residence times of H-2 on grain surfaces as a function of temperature. Some of the implications of these results are considered. RP SANDFORD, SA (reprint author), NASA,AMES RES CTR,MAIL STOP 245-6,MOFFETT FIELD,CA 94035, USA. NR 29 TC 65 Z9 65 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1993 VL 409 IS 2 BP L65 EP L68 DI 10.1086/186861 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC834 UT WOS:A1993LC83400009 PM 11540091 ER PT J AU THOMPSON, DJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HOFSTADTER, R HUGHES, EB HUNTER, SD HUGHLOCK, BW KANBACH, G KNIFFEN, DA LIN, YC MATTOX, JR MAYERHASSELWANDER, HA VONMONTIGNY, C NOLAN, PL NEL, HI PINKAU, K ROTHERMEL, H SCHNEID, EJ SOMMER, M SREEKUMAR, P TIEGER, D WALKER, AH AF THOMPSON, DJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HOFSTADTER, R HUGHES, EB HUNTER, SD HUGHLOCK, BW KANBACH, G KNIFFEN, DA LIN, YC MATTOX, JR MAYERHASSELWANDER, HA VONMONTIGNY, C NOLAN, PL NEL, HI PINKAU, K ROTHERMEL, H SCHNEID, EJ SOMMER, M SREEKUMAR, P TIEGER, D WALKER, AH TI CALIBRATION OF THE ENERGETIC GAMMA-RAY EXPERIMENT TELESCOPE (EGRET) FOR THE COMPTON GAMMA-RAY OBSERVATORY SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ARTIFICIAL SATELLITES, SPACE PROBES; GAMMA-RAYS, OBSERVATIONS; INSTRUMENTATION, DETECTORS; TELESCOPES ID COS-B; RADIATION; BEAM AB Calibration of the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory involves simulation, experimental calibration, and verification in flight. The principal properties of the instrument which have been determined as a function of energy and angle are the effective area, the angular resolution (point spread function), and the energy resolution (dispersion). C1 STANFORD UNIV, DEPT PHYS, STANFORD, CA 94305 USA. GRUMMAN AEROSP CORP, BETHPAGE, NY 11714 USA. HAMPDEN SYDNEY COLL, DEPT PHYS, HAMPDEN SYDNEY, VA 23943 USA. STANFORD UNIV, W W HANSEN EXPTL PHYS LAB, STANFORD, CA 94305 USA. MAX PLANCK INST EXTRATERR PHYS, W-8046 GARCHING, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, CTR COMPTON OBSERV SCI SUPPORT, GREENBELT, MD 20771 USA. MIT, BATES LINEAR ACCELERATOR CTR, MIDDLETON, MA 01949 USA. RP THOMPSON, DJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 28 TC 344 Z9 345 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1993 VL 86 IS 2 BP 629 EP 656 DI 10.1086/191793 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LD674 UT WOS:A1993LD67400012 ER PT J AU HUDGINS, DM SANDFORD, SA ALLAMANDOLA, LJ TIELENS, AGGM AF HUDGINS, DM SANDFORD, SA ALLAMANDOLA, LJ TIELENS, AGGM TI MIDINFRARED AND FAR-INFRARED SPECTROSCOPY OF ICES - OPTICAL-CONSTANTS AND INTEGRATED ABSORBANCES SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE LINE, IDENTIFICATION; MOLECULAR DATA ID AMORPHOUS SOLID WATER; MOLECULAR CLOUDS; ABSORPTION; ANALOGS; SPECTRA; METHANE; 10-K; H2O; CO AB Laboratory spectra through the mid-infrared (4000 to 500 cm-1 [2.5-20 mum]) have been used to calculate the optical constants (n and k) and integrated absorption coefficients (A) for a variety of pure and mixed molecular ices of relevance to astrophysics. The ices studied were H2O, CH3OH, CO2, OCS, CH4, CO2 + CH4, CO2 + OCS, CO + CH4, CO + OCS, O2 + CH4, O2 + OCS, N2 + CH4, N2 + OCS, H2O + CH4, H2O + OCS, and H2O + CH3OH + CO + NH3. In addition, the measurements have been extended through the far-infrared (500 to 50 cm-1 [20-200 mum]) for the H2O, CH3OH, and H2O + CH3OH + CO + NH3 ices. RP HUDGINS, DM (reprint author), NASA,AMES RES CTR,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 37 TC 319 Z9 319 U1 2 U2 32 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1993 VL 86 IS 2 BP 713 EP 870 DI 10.1086/191796 PG 158 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LD674 UT WOS:A1993LD67400015 PM 11539192 ER PT J AU FAREH, J COTTETEMARD, JM PEQUIGNOT, JM JAHNS, G MEYLOR, J VISO, M VASSAUX, D GAUQUELIN, G GHARIB, C AF FAREH, J COTTETEMARD, JM PEQUIGNOT, JM JAHNS, G MEYLOR, J VISO, M VASSAUX, D GAUQUELIN, G GHARIB, C TI NOREPINEPHRINE CONTENT IN DISCRETE BRAIN-AREAS AND NEUROHYPOPHYSEAL VASOPRESSIN IN RATS AFTER A 9-D SPACEFLIGHT (SLS-1) SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID ARGININE VASOPRESSIN; PRESSURE AB The norepinephrine (NE) content in discrete brain areas and the vasopressin content in the neurohypophysial system were assessed in rats after a 9-d spaceflight and after a recovery period (9 d). The NE content in the locus coeruleus decreased significantly in spaceflight rats (2.9 +/- 0.3 vs. 8.9 +/- 0.7 pmol . structure-1 for control rats, p < 0.001), but showed no difference between control and flight animals after a 9-d recovery. These findings were probably due to an acute stress undergone during landing. The NE content was unchanged in the A2 and A5 cell groups. In rats flown aboard SLS-1, the vasopressin content was increased in the posterior pituitary (1.47 +/- 0.1 vs. 0.86 +/- 0.1 mug . structure-1 for control rats, p < 0.0 1), and was significantly decreased in the hypothalamus (8.95 +/- 2.0 vs. 17.6 +/- 2.2 ng . structure-1, for control rats, p < 0.05). We conclude that the NE depletion in the locus coeruleus and the alteration in vasopressin release were consistent with an acute stress, likely occurring during and/or after landing. These changes tend to mask the actual neuroendocrine modifications caused by microgravity. C1 FAC MED LYON GRANGE BLANCHE,PHYSIOL ENVIRONNEMENT LAB,8 AVE ROCKEFELLER,F-69373 LYON 08,FRANCE. FAC MED LYON GRANGE BLANCHE,CNRS,URA 1196,LYON,FRANCE. NASA,AMES RES CTR,LOCKHEED ENGN & SCI CO,MOFFETT FIELD,CA 94035. CNES,PARIS,FRANCE. NR 24 TC 10 Z9 10 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 1993 VL 64 IS 6 BP 507 EP 511 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA LE075 UT WOS:A1993LE07500004 PM 8338496 ER PT J AU DEROSHIA, CW GREENLEAF, JE AF DEROSHIA, CW GREENLEAF, JE TI PERFORMANCE AND MOOD-STATE PARAMETERS DURING 30-DAY 6-DEGREES HEAD-DOWN BED REST WITH EXERCISE TRAINING SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article AB The study was designed to determine if performance and mood impairments occur in bed-rested subjects, and if different exercise-training regimens modify or prevent them. Eighteen normal, healthy men were divided on the basis of age, peak oxygen uptake, and maximal isometric knee extension strength into three similar groups: no exercise (NOE), isotonic exercise (ITE), and isokinetic exercise (IKE). A 15-min battery of 10 performance tests and 8 mood and 2 sleep scales were administered daily during ambulatory control, 30 d of absolute bed rest (BR), and 4 d of ambulatory recovery. Performance test proficiency increased (p < 0.05) for all three groups during BR in 7 of 10 tests and there were no consistent significant differences between the three groups. However, during BR, the ITE group was distinguished from the other groups by a decline (p < 0.05) in the activation mood dimension and in two of its constituent scales (motivation and concentration), and by improvement (p < 0.05) in the trouble-falling-asleep and psychological-tension scales. Since few deleterious changes in performance and mood occurred in the three groups and did not exceed baseline ambulatory levels, we conclude that mood and performance did not deteriorate in response to prolonged BR and were not altered by exercise training. However, the decline in activation mood scales in the ITE group may reflect overtraining or excess total workload in this group. C1 NASA,AMES RES CTR,DIV LIFE SCI 23911,HUMAN GRAVITAT PHYSIOL LAB,MOFFETT FIELD,CA 94035. NR 29 TC 18 Z9 19 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUN PY 1993 VL 64 IS 6 BP 522 EP 527 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA LE075 UT WOS:A1993LE07500007 PM 8338499 ER PT J AU SOHN, BJ ROBERTSON, FR AF SOHN, BJ ROBERTSON, FR TI INTERCOMPARISON OF OBSERVED CLOUD RADIATIVE FORCING - A ZONAL AND GLOBAL PERSPECTIVE SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID GENERAL-CIRCULATION MODEL; SURFACE-TEMPERATURE; BUDGET EXPERIMENT; CLIMATE; FEEDBACK; ALGORITHMS; SATELLITE; LONGWAVE; BALANCE AB Despite the general agreement that clouds cool the earth-atmosphere, there are substantial differences in estimated magnitudes of the annual global mean of cloud radiative forcing. Recent estimates of globally averaged net cloud radiative forcing range from -2 to -27 W m-2. The reasons for these differences have not been clarified in spite of the important role of clouds in maintaining global heat balance. Here, three estimation methods [Earth Radiation Budget Experiment (ERBE), Regression I, and Regression II] are compared using the same data source and analysis period. Intercomparison has been done for the time period of February and March 1985 over which major satellite radiation budget and cloudiness datasets (ERBE radiation budget, Nimbus-7, and ISCCP cloudiness) are contemporaneous. The global averages of five sets of net cloud radiative forcing by three independent methods agree to within 3.5 W m-2; four of five cases agree to within 1 W m-2. This suggests that differences in published global mean values of net cloud radiative forcing are mainly due to different data sources and analysis periods and a best estimated annual mean among all previous estimates appears to be the ERBE measurement, that is, -17.3 W m-2 . In contrast to the close agreement in the net cloud radiative forcing estimates, both longwave and shortwave cloud radiative forcing show more dependence on the chosen method and dataset. The bias of regression-retrieved values between Nimbus-7 and ISCCP cloud climatology is largely attributed to the difference in total cloudiness between two climatologies whereas the discrepancies between the ERBE and regression method appear to be, in part, due to the conceptually different definition of clear-sky flux. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RI Kim, Bo-Ra/E-6100-2013 NR 32 TC 16 Z9 16 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1993 VL 74 IS 6 BP 997 EP 1006 DI 10.1175/1520-0477(1993)074<0997:IOOCRF>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LK413 UT WOS:A1993LK41300001 ER PT J AU BOURHILL, G MANSOUR, K PERRY, KJ KHUNDKAR, L SLEVA, ET KERN, R PERRY, JW WILLIAMS, ID KURTZ, SK AF BOURHILL, G MANSOUR, K PERRY, KJ KHUNDKAR, L SLEVA, ET KERN, R PERRY, JW WILLIAMS, ID KURTZ, SK TI POWDER 2ND-HARMONIC GENERATION EFFICIENCIES OF SACCHARIDE MATERIALS SO CHEMISTRY OF MATERIALS LA English DT Article ID CRYSTALS; BORATE; FORM AB Saccharide materials are potential candidates for frequency conversion applications. In addition to being chiral, which ensures crystallization in a space group necessary for three-wave mixing processes, they generally possess useful physical and optical properties. We have examined the powder second harmonic generation efficiencies of both saturated saccharides and sugars with simple polar pi-functionalities. Powder efficiencies of up to 5 times that of sucrose were observed for simple saturated sugars, whereas values of 18 times sucrose (or 0.45 X urea) were observed for unsaturated saccharide derivatives. We have noted that for both classes of material, there is a tendency for more efficient nonlinear compounds to reside in a monoclinic rather than an orthorhombic space group. We have also noted that there appears to be a correlation between the phase-matching potential and the crystal symmetry. In addition, two promising saccharide materials have been identified for frequency conversion applications, based on their powder second-harmonic generation efficiencies, their phase-matching capabilities, and their UV transparency. C1 JET PROP LAB, PASADENA, CA 91109 USA. PENN STATE UNIV, MAT RES LAB, UNIV PK, PA 16802 USA. RI Perry, Joseph/B-7191-2011; williams, ian/B-2907-2009 OI Perry, Joseph/0000-0003-1101-7337; williams, ian/0000-0001-8743-401X NR 22 TC 20 Z9 20 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 EI 1520-5002 J9 CHEM MATER JI Chem. Mat. PD JUN PY 1993 VL 5 IS 6 BP 802 EP 808 DI 10.1021/cm00030a015 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA LJ153 UT WOS:A1993LJ15300015 ER PT J AU CHOU, JJ BLAKE, MW AF CHOU, JJ BLAKE, MW TI PLANAR CUBICS THROUGH A POINT IN A DIRECTION SO COMPUTER-AIDED DESIGN LA English DT Note DE BEZIER CUBICS; CURVE FITTING; PLANAR CURVES; DATA REDUCTION AB It is shown that the planar cubics through three points and the associated tangent directions can be found by solving a cubic equation and a 2 x 2 system of linear equations. The result is combined with a previous published scheme to produce a better curve-fitting method. RP CHOU, JJ (reprint author), NASA,AMES RES CTR,COMP SCI CORP,M-S 258-6,MOFFETT FIELD,CA 94035, USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0010-4485 J9 COMPUT AIDED DESIGN JI Comput.-Aided Des. PD JUN PY 1993 VL 25 IS 6 BP 348 EP 354 DI 10.1016/0010-4485(93)90029-N PG 7 WC Computer Science, Software Engineering SC Computer Science GA LH329 UT WOS:A1993LH32900003 ER PT J AU BECKER, JC DAGUM, L AF BECKER, JC DAGUM, L TI PARTICLE SIMULATION ON HETEROGENEOUS DISTRIBUTED SUPERCOMPUTERS SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article AB We describe the implementation and performance of a three dimensional particle simulation distributed between a Thinking Machines CM-2 and a Cray Y-MP. These are connected by a combination of two high-speed networks: a high-performance parallel interface (HIPPI) and an optical network (UltraNet). This is the first application to use this configuration at NASA Ames Research Center. We describe our experience implementing and using the application and report the results or several timing measurements. We show that the distribution of applications across disparate supercomputing platforms is feasible and has reasonable performance. In addition, several practical aspects of the computing environment are discussed. C1 UNIV CALIF DAVIS,DIV COMP SCI,DAVIS,CA 95616. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 5 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD JUN PY 1993 VL 5 IS 4 BP 367 EP 377 DI 10.1002/cpe.4330050411 PG 11 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA LJ224 UT WOS:A1993LJ22400010 ER PT J AU HERRMANN, CC AF HERRMANN, CC TI HIGH RECOVERY REVERSE-OSMOSIS USING A RECYCLE LOOP SO DESALINATION LA English DT Article AB A single-pump configuration with feedback has been found useful in reaching high brine osmotic pressures in continuous-flow operation. Enhanced brine concentration, and enhanced product/feed water recovery fraction, can be obtained by recycle of a second-stage permeate of intermediate quality. For spaceflight recycling of hygiene water this permits lower pressure-vessel ratings, or higher water recovery, or both. With feed of 1,000 ppM concentration, recoveries of 95-97% are achieved at a pressure of 1.65 MPa. With feed of seawater concentration, recoveries of 50% to 70% have been achieved using a single pump at 5.5 MPa. Membrane performance parameters have been obtained for high water recovery operation in the pressure range up to 1.4 MPascals (200 psig) for system modeling. Simple equations can be fitted to these measurements, from which RO system performance can be predicted, or simulated as part of a model of system performance. C1 NASA,AMES RES CTR,BIONET INC,MOFFETT FIELD,CA 94035. NR 15 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0011-9164 J9 DESALINATION JI Desalination PD JUN PY 1993 VL 91 IS 3 BP 279 EP 292 DI 10.1016/0011-9164(93)80065-U PG 14 WC Engineering, Chemical; Water Resources SC Engineering; Water Resources GA LQ835 UT WOS:A1993LQ83500005 ER PT J AU ELLIS, SR AF ELLIS, SR TI VIRTUAL REALITY - RHEINGOLD,H SO ERGONOMICS LA English DT Book Review RP ELLIS, SR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0014-0139 J9 ERGONOMICS JI Ergonomics PD JUN PY 1993 VL 36 IS 6 BP 743 EP 744 DI 10.1080/00140139308967935 PG 2 WC Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Engineering; Psychology GA LB736 UT WOS:A1993LB73600013 ER PT J AU ANTONIA, RA ZHU, Y KIM, J AF ANTONIA, RA ZHU, Y KIM, J TI ON THE MEASUREMENT OF LATERAL VELOCITY DERIVATIVES IN TURBULENT FLOWS SO EXPERIMENTS IN FLUIDS LA English DT Article ID SPECTRUM AB Direct numerical simulation data for the lateral velocity derivative partial derivative u/partial derivative y at the centreline of a fully developed turbulent channel flow provide reasonable support for Wyngaard's analysis of the error involved in measuring this quantity using parallel hot wires. Numerical data in the wall region of the channel flow also provide a useful indication of how to select the separation between the wires. Justification for this choice is obtained by comparing several measured statistics of partial derivative u/partial derivative y with the corresponding numerical data. C1 NASA,AMES RES CTR,CTR TURBULENCE RES,MOFFETT FIELD,CA 94035. RP ANTONIA, RA (reprint author), UNIV NEWCASTLE,DEPT MECH ENGN,NEWCASTLE,NSW 2308,AUSTRALIA. RI Zhu, Yonggang/B-3362-2012 OI Zhu, Yonggang/0000-0002-5419-9508 NR 13 TC 48 Z9 48 U1 2 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD JUN PY 1993 VL 15 IS 1 BP 65 EP 69 PG 5 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA LK433 UT WOS:A1993LK43300009 ER PT J AU NAYLOR, R MATSON, P AF NAYLOR, R MATSON, P TI DEVELOPING AN INTEGRATED APPROACH SO FOOD POLICY LA English DT Editorial Material C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP NAYLOR, R (reprint author), STANFORD UNIV,INST INT STUDIES,STANFORD,CA 94305, USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0306-9192 J9 FOOD POLICY JI Food Policy PD JUN PY 1993 VL 18 IS 3 BP 249 EP 251 DI 10.1016/0306-9192(93)90082-M PG 3 WC Agricultural Economics & Policy; Economics; Food Science & Technology; Nutrition & Dietetics SC Agriculture; Business & Economics; Food Science & Technology; Nutrition & Dietetics GA LJ790 UT WOS:A1993LJ79000008 ER PT J AU OBERBECK, VR AF OBERBECK, VR TI ORIGIN OF TILLITES SO GEOTIMES LA English DT Letter RP OBERBECK, VR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 SN 0016-8556 J9 GEOTIMES JI Geotimes PD JUN PY 1993 VL 38 IS 6 BP 4 EP 4 PG 1 WC Geosciences, Multidisciplinary SC Geology GA LE186 UT WOS:A1993LE18600001 ER PT J AU SELLERS, P SCHIMEL, D AF SELLERS, P SCHIMEL, D TI REMOTE-SENSING OF THE LAND BIOSPHERE AND BIOGEOCHEMISTRY IN THE EOS ERA - SCIENCE PRIORITIES, METHODS AND IMPLEMENTATION - EOS LAND BIOSPHERE AND BIOGEOCHEMICAL CYCLES PANELS SO GLOBAL AND PLANETARY CHANGE LA English DT Article ID FOREST ECOSYSTEMS; CLIMATE CHANGE; MODEL; NITROGEN; CO2; RESPIRATION; CARBON C1 COLORADO STATE UNIV, NREL, FT COLLINS, CO 80523 USA. RP SELLERS, P (reprint author), NASA, GODDARD SPACE FLIGHT CTR, 923, GREENBELT, MD 20771 USA. NR 27 TC 53 Z9 58 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD JUN PY 1993 VL 7 IS 4 BP 279 EP 297 DI 10.1016/0921-8181(93)90002-6 PG 19 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA LL090 UT WOS:A1993LL09000002 ER PT J AU BEGAULT, DR WENZEL, EM AF BEGAULT, DR WENZEL, EM TI HEADPHONE LOCALIZATION OF SPEECH SO HUMAN FACTORS LA English DT Article ID SOUND LOCALIZATION; SPECTRAL CUES; MEDIAN PLANE; FIELD; LATERALIZATION; SIMULATION AB Three-dimensional acoustic display systems have recently been developed that synthesize virtual sound sources over headphones based on filtering by head-related transfer functions (HRTFs), the direction-dependent spectral changes caused primarily by the pinnae. In this study 11 inexperienced subjects judged the apparent spatial location of headphone-presented speech stimuli filtered with non-individualized HRTFs. About half of the subjects ''pulled'' their judgments toward either the median or the lateral-vertical planes, and estimates were almost always elevated. Individual differences were pronounced for the distance judgments; 15% to 46% of stimuli were heard inside the head, with the shortest estimates near the median plane. The results suggest that most listeners can obtain useful azimuth information from speech stimuli filtered by nonindividualized HRTFs. Measurements of localization error and reversal rates are comparable with a previous study that used broadband noise stimuli. RP BEGAULT, DR (reprint author), NASA,AMES RES CTR,MS 262-2,MOFFETT FIELD,CA 94035, USA. NR 46 TC 51 Z9 51 U1 0 U2 5 PU HUMAN FACTORS SOC PI SANTA MONICA PA BOX 1369, SANTA MONICA, CA 90406 SN 0018-7208 J9 HUM FACTORS JI Hum. Factors PD JUN PY 1993 VL 35 IS 2 BP 361 EP 376 PG 16 WC Behavioral Sciences; Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Behavioral Sciences; Engineering; Psychology GA LL764 UT WOS:A1993LL76400010 PM 8349292 ER PT J AU FRENCH, RG NICHOLSON, PD COOKE, ML ELLIOT, JL MATTHEWS, K PERKOVIC, O TOLLESTRUP, E HARVEY, P CHANOVER, NJ CLARK, MA DUNHAM, EW FORREST, W HARRINGTON, J PIPHER, J BRAHIC, A GRENIER, I ROQUES, F ARNDT, M AF FRENCH, RG NICHOLSON, PD COOKE, ML ELLIOT, JL MATTHEWS, K PERKOVIC, O TOLLESTRUP, E HARVEY, P CHANOVER, NJ CLARK, MA DUNHAM, EW FORREST, W HARRINGTON, J PIPHER, J BRAHIC, A GRENIER, I ROQUES, F ARNDT, M TI GEOMETRY OF THE SATURN SYSTEM FROM THE 3 JULY 1989 OCCULTATION OF 28-SGR AND VOYAGER OBSERVATIONS SO ICARUS LA English DT Article ID RADIO OCCULTATION; URANIAN RINGS; STELLAR OCCULTATION; ENCKE GAP; FEATURES; ORBITS; IDENTIFICATION; ENCOUNTER; MOONLET; NEPTUNE C1 CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853. MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. CALTECH,PALOMAR OBSERV,PASADENA,CA 91125. HARVARD SMITHSONIAN CTR ASTROPHYS,CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. KANSAS STATE UNIV AGR & APPL SCI,DEPT ART,MANHATTAN,KS 66506. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV ROCHESTER,DEPT ASTRON,ROCHESTER,NY 14627. OBSERV PARIS,F-92190 MEUDON,FRANCE. RP FRENCH, RG (reprint author), WELLESLEY COLL,DEPT ASTRON,WELLESLEY,MA 02181, USA. RI Harrington, Joseph/E-6250-2011 NR 70 TC 66 Z9 66 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 1993 VL 103 IS 2 BP 163 EP 214 DI 10.1006/icar.1993.1066 PG 52 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LK928 UT WOS:A1993LK92800001 ER PT J AU DOBROVOLSKIS, AR AF DOBROVOLSKIS, AR TI ATMOSPHERIC TIDES ON VENUS .4. TOPOGRAPHIC WINDS AND SEDIMENT TRANSPORT SO ICARUS LA English DT Article ID BOUNDARY-LAYER; SALTATION; MARS RP DOBROVOLSKIS, AR (reprint author), NASA,AMES RES CTR,245-3,MOFFETT FIELD,CA 94035, USA. NR 34 TC 8 Z9 8 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 1993 VL 103 IS 2 BP 276 EP 289 DI 10.1006/icar.1993.1070 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LK928 UT WOS:A1993LK92800005 ER PT J AU ELEFTHERIADES, GV REBEIZ, GM AF ELEFTHERIADES, GV REBEIZ, GM TI DESIGN AND ANALYSIS OF QUASI-INTEGRATED HORN ANTENNAS FOR MILLIMETER AND SUBMILLIMETER-WAVE APPLICATIONS SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article AB The purpose of this paper is to present a systematic process for the design of multimode quasi-integrated horn antennas, and to provide a full range of practical antenna designs for mullimeter and submillimeter-wave applications. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is employed in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate model. This results in a simple and efficient design process. The developed design procedure has been applied for the design of a 20-, 23-, and 25-dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97%. The designed antennas have been tested and characterized using both full-wave analysis and 91/370GHz measurements. The quasi-integrated horn antennas are also examined as feed elements for Cassegrain antenna systems and are proven to be comparable to the traditional machined corrugated horn feeds. RP ELEFTHERIADES, GV (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. NR 20 TC 8 Z9 8 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JUN-JUL PY 1993 VL 41 IS 6-7 BP 954 EP 965 DI 10.1109/22.238509 PG 12 WC Engineering, Electrical & Electronic SC Engineering GA MC680 UT WOS:A1993MC68000008 ER PT J AU MASSIEON, CC CUTLER, AH SHADMAN, F AF MASSIEON, CC CUTLER, AH SHADMAN, F TI HYDROGEN REDUCTION OF IRON-BEARING SILICATES SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article AB The kinetics and mechanism of the reduction of olivine by H-2 have been studied at H-2 partial pressures between 0.046 and 0.14 atm and temperatures from 1070 to 1370 K. For Fa93 (Fe1.86-Mg0.14SiO4), the reaction order with respect to H-2 is 0.8 and the activation energy is 205 kJ/mol for conversions up to 40%. For Fa100 (Fe2SiO4), the reaction order is 0.5 and the activation energy is 260 kJ/mol. The apparent kinetic parameters do not change significantly as conversion increases from about 15 to 60%. Mg2+ is less reducible than Fe2+, and its presence slows the reaction. The solid products of the reaction are metallic iron and vitreous silica. The products form a nonporous layer around an unreacted core. Permeation of H-2 through this layer is important in determining the rate of reaction. C1 UNIV ARIZONA,DEPT CHEM ENGN,TUCSON,AZ 85721. UNIV ARIZONA,NASA,SPACE ENGN RES CTR,TUCSON,AZ 85721. NR 18 TC 8 Z9 9 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD JUN PY 1993 VL 32 IS 6 BP 1239 EP 1244 DI 10.1021/ie00018a033 PG 6 WC Engineering, Chemical SC Engineering GA LG558 UT WOS:A1993LG55800033 ER PT J AU GOBBA, WA PATTERSON, JD LEHOCZKY, SL AF GOBBA, WA PATTERSON, JD LEHOCZKY, SL TI A COMPARISON BETWEEN ELECTRON MOBILITIES IN HG1-XMNXTE AND HG1-XCDXTE SO INFRARED PHYSICS LA English DT Article ID DILUTED MAGNETIC SEMICONDUCTORS; EPITAXIAL LAYERS; TRANSPORT; ALLOYS; GAP; INTERFACE; CRYSTALS; LATTICE; PHYSICS; GROWTH AB Electron mobility in the n-type diluted magnetic semiconductor Hg1-xMnxTe has been calculated in the absence of a magnetic field. The results were compared to those of Hg1-xCdxTe for the same range of energy gap. The calculations are based on solving the Boltzmann equation using a variational principle technique. The scattering processes that are included in the calculations are the scattering of the electrons with ionized impurities, holes, alloy disorder, acoustic phonons and longitudinal optical phonons. At room temperatures the mobilities are nearly the same, while at temperatures of the order of liquid nitrogen they are about 30% less for MMT as compared with the same concentration of defects. C1 MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP GOBBA, WA (reprint author), FLORIDA INST TECHNOL,DEPT PHYS & SPACE SCI,MELBOURNE,FL 32901, USA. NR 52 TC 1 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-0891 J9 INFRARED PHYS PD JUN PY 1993 VL 34 IS 3 BP 311 EP 321 DI 10.1016/0020-0891(93)90019-4 PG 11 WC Optics; Physics, Applied SC Optics; Physics GA LH404 UT WOS:A1993LH40400007 ER PT J AU Keppenne, CL Ghil, M AF Keppenne, Christian L. Ghil, Michael TI ADAPTIVE FILTERING AND PREDICTION OF NOISY MULTIVARIATE SIGNALS: AN APPLICATION TO SUBANNUAL VARIABILITY IN ATMOSPHERIC ANGULAR MOMENTUM SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article AB Principal component analysis (PCA) in the space and time domains is applied to filter adaptively the dominant modes of subannual (SA) variability of a 12-year long multivariate time series of Northern Hemisphere atmospheric angular momentum (AAM); AAM is computed in 23 latitude bands of equal area from operational analyses of the U.S. National Meteorological Center. PCA isolates the leading empirical orthogonal functions (EOFs) of spatial dependence, while multivariate singular spectrum analysis (M-SSA) yields filtered time series that capture the dominant low-frequency modes of SA variability. The time series prefiltered by M-SSA lend themselves to prediction by the maximum entropy method (MEM). Whole-field predictions are made by combining the forecasts so obtained with the leading spatial EOFs obtained by PCA. The combination of M-SSA and MEM has predictive ability up to about a month. These methods are essentially linear but data-adaptive. They seem to perform well for short, noisy, multivariate time series, to which purely nonlinear, deterministically based methods are difficult to apply. C1 [Keppenne, Christian L.; Ghil, Michael] Univ Calif Los Angeles, Ctr Climate Dynam, Los Angeles, CA 90024 USA. [Keppenne, Christian L.; Ghil, Michael] Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. [Keppenne, Christian L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Ghil, Michael] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. RP Keppenne, CL (reprint author), Univ Calif Los Angeles, Ctr Climate Dynam, Los Angeles, CA 90024 USA. FU National Aeronautics and Space Administration; National Science Foundation's Climate Dynamics Program; National Oceanic and Atmospheric Administration's Climate and Global Change Program; Guggenheim Fellowship; JPL FX The research described in this paper was carried out at the University of California, Los Angeles (UCLA), and at the Jet Propulsion Laboratory (JPL), California Institute of Technology under a contract with the National Aeronautics and Space Administration. The work was supported by a grant from the National Science Foundation's Climate Dynamics Program to UCLA, a grant from the National Oceanic and Atmospheric Administration's Climate and Global Change Program to UCLA and JPL, and a Guggenheim Fellowship to Michael Ghil. We are grateful to R. Rosen for supplying the National Meteorological Center data. NR 48 TC 39 Z9 40 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-1274 EI 1793-6551 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD JUN PY 1993 VL 3 IS 3 BP 625 EP 634 DI 10.1142/S0218127493000520 PG 10 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA V44LR UT WOS:000209751000014 ER PT J AU Vassiliadis, D AF Vassiliadis, Dimitris TI PARAMETRIC ADAPTIVE CONTROL OF AN NMR LASER MODEL SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article AB The parametric adaptive control method can be used to restore the values of the perturbed parameters of a low-dimensional system. The article illustrates the method by applying it to an NMR laser model. C1 [Vassiliadis, Dimitris] NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-1274 EI 1793-6551 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD JUN PY 1993 VL 3 IS 3 BP 793 EP 796 DI 10.1142/S0218127493000726 PG 4 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA V44LR UT WOS:000209751000034 ER PT J AU DEMUREN, AO AF DEMUREN, AO TI CHARACTERISTICS OF 3-DIMENSIONAL TURBULENT JETS IN CROSS-FLOW SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article ID NAVIER-STOKES EQUATIONS; FLOW AB Three-dimensional turbulent jets in crossflow at low to medium jet-to-crossflow velocity ratios are computed with a finite-volume numerical procedure which utilizes a second-moment closure model to approximate the Reynolds stresses. A multigrid method is used to accelerate the convergence rate of the procedure. Comparison of the computations to measured data shows good qualitative agreement. All trends are correctly predicted, though there is some uncertainty on the height of penetration of the jet. The evolution of the vorticity field is used to explore the jet-crossflow interaction. C1 NASA,LEWIS RES CTR,ICOMP,CLEVELAND,OH 44135. NR 18 TC 30 Z9 40 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD JUN PY 1993 VL 31 IS 6 BP 899 EP 913 DI 10.1016/0020-7225(93)90102-Z PG 15 WC Engineering, Multidisciplinary SC Engineering GA KY966 UT WOS:A1993KY96600007 ER PT J AU SIMONEAU, RJ SIMON, FF AF SIMONEAU, RJ SIMON, FF TI PROGRESS TOWARDS UNDERSTANDING AND PREDICTING HEAT-TRANSFER IN THE TURBINE GAS PATH SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Review DE HEAT TRANSFER; COMPUTATIONAL FLUID DYNAMICS; MODELING; TURBINE; TRANSITION; 3-DIMENSIONAL FLOW; FILM COOLING ID ROTOR-STATOR INTERACTION; NAVIER-STOKES SIMULATIONS; LOW-REYNOLDS-NUMBER; AXIAL-FLOW TURBINE; NOZZLE GUIDE VANE; BOUNDARY-LAYER; ROTATING TURBINE; UNSTEADY TRANSITION; SHEAR FLOWS; BLADE ROWS AB A new era is dawning in the ability to predict convection heat transfer in the turbine gas path. We feel that the technical community now has the capability to mount a major assault on this problem, which has eluded significant progress for a long time. In this paper we hope to make a case for this bold statement by reviewing the state of the art in three major and related areas, which we believe are indispensable to the understanding and accurate prediction of turbine gas path heat transfer: configuration-specific experiments, fundamental physics and model development, and code development. We begin our review with the configuration-specific experiments, whose data have provided the big picture and guided both the fundamental modeling research and the code development. Following that, we will examine key modeling efforts and comment on what will be needed to incorporate them into the codes. In this region we will concentrate on bypass transition, three-dimensional endwalls, and film cooling. We will then review progress and directions in the development of computer codes to predict turbine gas path heat transfer. Finally, we will cite examples and make observations on the more recent efforts to do all this work in a simultaneous, interactive, and more synergistic manner. We will conclude with an assessment of progress, suggestions for how to use the current state of the art, and recommendations for the future. RP SIMONEAU, RJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 176 TC 34 Z9 34 U1 1 U2 14 PU BUTTERWORTH-HEINEMANN PI WOBURN PA 225 WILDWOOD AVE #UNITB PO BOX 4500, WOBURN, MA 01801-2084 SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD JUN PY 1993 VL 14 IS 2 BP 106 EP 128 DI 10.1016/0142-727X(93)90019-J PG 23 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA LK184 UT WOS:A1993LK18400001 ER PT J AU SINHA, SK SUNDARARAJAN, T GARG, VK AF SINHA, SK SUNDARARAJAN, T GARG, VK TI A STUDY OF THE EFFECTS OF MACROSEGREGATION AND BUOYANCY-DRIVEN FLOW IN BINARY MIXTURE SOLIDIFICATION SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID INTERDENDRITIC LIQUID; TRANSPORT; MOMENTUM; SYSTEMS; MODEL; HEAT; MASS AB A generalized anisotropic porous medium approach is developed for modelling the flow, heat and mass transport processes during binary mixture solidification. Transient predictions are obtained using FEM, coupled with an implicit time-marching scheme, for solidification inside a two-dimensional rectangular enclosure. A parametric study focusing attention on the effects of solutal buoyancy and thermal buoyancy is presented. It is observed that three parameters, namely the thermal Rayleigh number (Ra(theta)), the solutal Rayleigh number (Ra(F)) and the relative density change parameter (sigma2), Significantly alter the flow fields in the liquid and the mushy regions. Depending upon the nature of these flow fields, the solute enrichment caused by macrosegregation may occur on the top or the bottom region of the enclosure. C1 NASA, LEWIS RES CTR, MAIL STOP 5-11, 21000 BROOKPK RD, CLEVELAND, OH 44135 USA. DELHI INST TECHNOL, DEPT MECH ENGN, DELHI 110006, INDIA. INDIAN INST TECHNOL, DEPT MECH ENGN, KANPUR 208016, UTTAR PRADESH, INDIA. NR 19 TC 4 Z9 4 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 EI 1879-2189 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD JUN PY 1993 VL 36 IS 9 BP 2349 EP 2358 DI 10.1016/S0017-9310(05)80119-X PG 10 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA LF265 UT WOS:A1993LF26500010 ER PT J AU WU, TK CHANDLER, CW AF WU, TK CHANDLER, CW TI OPTICAL BEAM FORMING TECHNIQUES FOR PHASED-ARRAY ANTENNAS SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article AB Three optical beam forming techniques are identified as applicable to large spaceborne phased array antennas. They are 1) the fiber replacement of conventional RF phased array distribution and control components, 2) spatial beam forming, and 3) optical beam splitting techniques. Two novel optical beam forming approaches, i.e., the spatial beam forming with a ''smart pixel'' spatial light modulator (SLM) and the optical beam splitting approaches are conceived with integrated quasi-optical components. Also presented are the transmit and receive array architectures with the new SLM. RP WU, TK (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD JUN PY 1993 VL 14 IS 6 BP 1191 EP 1199 DI 10.1007/BF02146250 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA LH422 UT WOS:A1993LH42200002 ER PT J AU CARTER, GA YOUNG, DR AF CARTER, GA YOUNG, DR TI FOLIAR SPECTRAL REFLECTANCE AND PLANT STRESS ON A BARRIER-ISLAND SO INTERNATIONAL JOURNAL OF PLANT SCIENCES LA English DT Article ID LEAF WATER-CONTENT; MYRICA-CERIFERA; VIRGINIA; PINE; DYNAMICS; LEAVES AB Leaf spectral reflectance was measured in the field to provide estimates of plant stress for a barrier island interior. During summer on Horn Island, Mississippi, visible (400-760 nm wavelengths) reflectance in Myrica cerifera L. was slightly greater on a site that remained flooded compared to an adjacent site that remained relatively dry, indicating only mild stress on the flooded site. This coincided with leaf water potentials, conductances to water vapor diffusion, and foliar element concentrations that were similar between the two sites. Although Na and Cl concentrations were much greater on the island than on a mainland site, visible reflectances and chlorophyll a concentrations indicated that M. cerifera was not stressed in comparison to the mainland. In Pinus elliottii Engelm., greater visible reflectance on the flooded than on the dry island site and on both island sites compared with the mainland indicated appreciable stress. These reflectance responses to the island environment, particularly reflectance increases near 600 nm and 700 nm, were spectrally similar to those reported previously for a variety of environmental conditions that inhibit growth. Infrared (760-2500 nm) reflectance also differed among sites for both species but was less sensitive to the barrier island environment than visible reflectance. Reflectances indicated that M. cerifera was adapted better than P. elliottii to the barrier island environment, particularly in saturated soils. C1 VIRGINIA COMMONWEALTH UNIV,DEPT BIOL,RICHMOND,VA 23284. RP CARTER, GA (reprint author), NASA,SCI & TECHNOL LAB,BAY ST LOUIS,MS 39529, USA. NR 29 TC 11 Z9 12 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 1058-5893 J9 INT J PLANT SCI JI Int. J. Plant Sci. PD JUN PY 1993 VL 154 IS 2 BP 298 EP 305 DI 10.1086/297110 PG 8 WC Plant Sciences SC Plant Sciences GA LP123 UT WOS:A1993LP12300006 ER PT J AU KOBLINSKY, CJ RYAN, J BRAATZ, L KLOSKO, SM AF KOBLINSKY, CJ RYAN, J BRAATZ, L KLOSKO, SM TI A DIRECT EVALUATION OF THE GEOSAT ALTIMETER WET ATMOSPHERIC RANGE DELAY USING VERY LONG-BASE-LINE INTERFEROMETRY OBSERVATIONS SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Note ID TROPOSPHERIC CORRECTION; OCEAN CIRCULATION; RADAR ALTIMETER; VARIABILITY; TOPOGRAPHY; SATELLITE; GEODESY; PACIFIC AB The U.S. Navy's Geosat altimeter mission between 1985 and 1989 provided the first long-term measurements of sea surface topography with sufficient accuracy to observe large-scale changes in the ocean circulation. However, the overall accuracy of these measurements has been difficult to assess because of the lack of coincident measurements of the radar range corrections. In particular, Geosat, unlike Seasat, did not make simultaneous measurements of the range delay caused by refraction from atmospheric water vapour. This delay varies between 5 and 50 cm. In order to correct for this delay, estimates of columnar water vapour in the altimeter path are modelled using estimates from numerical weather forecast models or non-coincident satellite measurements. Comparisons of these estimates with direct radiosonde measurements have been made by others and clearly indicate a preference for the satellite measurement over the forecast model. NASA's Very Long Baseline Interferometry programme routinely estimates the wet tropospheric range delay at radio frequencies for all antenna locations at 15 minute intervals with a precision of a few cm rms. We have used these measurements to make a direct assessment of the Geosat wet troposphere range correction. The VLBI measurements show strong diurnal variations in columnar water vapour at several sites. These variations are a source of error (order 3 cm root-mean-square) in any non-coincident measurement of the wet troposphere range delay. These errors can be aliased to lower frequencies because of the satellite sampling scheme and have an effect on studies of annual and interannual changes in sea level with Geosat data. C1 ST SYST CORP,LANHAM,MD 20706. RP KOBLINSKY, CJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 926,GREENBELT,MD 20771, USA. NR 22 TC 0 Z9 0 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 1993 VL 14 IS 9 BP 1723 EP 1733 PG 11 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA LR589 UT WOS:A1993LR58900008 ER PT J AU BLIVEN, LF GIOVANANGELI, JP WANNINKHOF, RH CHAPRON, B AF BLIVEN, LF GIOVANANGELI, JP WANNINKHOF, RH CHAPRON, B TI A LABORATORY STUDY OF FRICTION-VELOCITY ESTIMATES FROM SCATTEROMETRY - LOW AND HIGH REGIMES SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID WIND-WAVE TANK; RADAR BACKSCATTER; SEA-SURFACE; ROUGHNESS; MODEL; SPEED AB Measurements from scatterometers pointing at wind-waves in three large wave-tanks are examined to study fetch effects and the correlation with wind friction-velocity u*. Time-series measurements were made at 13, 35, and 95 m with a K(a)-band scatterometer aimed upwind at 30-degrees incidence angle and vertical polarization. Average normalized radar cross-section sigma0 values from all fetches follow a common trend for sigma0 as a function of u*, so the fetch dependence is negligible. An empirical power-law model yields a high correlation between sigma0 and u*, but because systematic anomalies arise, we re-examine a turbulence approach that delineates low and high regimes with a transition at u* of approximately 25 cm s-1. Using this criteria, the data are well represented by a two-section power-law relationship between sigma0 and u*. C1 INST MECAN STAT TURBULENCE,F-13303 MARSEILLE,FRANCE. NOAA,AOML,DEPT OCEAN CHEM,MIAMI,FL 33149. IFREMER,CTR BREST,DROOS,F-29270 PLOUZANE,FRANCE. RP BLIVEN, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. RI bliven, francis/E-1450-2012; Chapron, Bertrand/O-6527-2015 NR 24 TC 4 Z9 4 U1 0 U2 5 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 1993 VL 14 IS 9 BP 1775 EP 1785 PG 11 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA LR589 UT WOS:A1993LR58900011 ER PT J AU RONDEAUX, G VANDERBILT, VC AF RONDEAUX, G VANDERBILT, VC TI SPECULARLY MODIFIED VEGETATION INDEXES TO ESTIMATE PHOTOSYNTHETIC ACTIVITY SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Letter ID HIGH-RESOLUTION RADIOMETER; CANOPY REFLECTANCE; POLARIZED-LIGHT; SATELLITE DATA; MODEL; TRANSPIRATION; DIFFUSE; INDEX AB The hypothesis tested was that some part of the ecosystem-dependent variability of vegetation indices was attributable to the effects of light specularly reflected by leaves. 'Minus specular' indices were defined excluding effects of specular light which contains no cellular pigment information. Results, both empirical and theoretical, show that the 'minus specular' indices, when compared to the traditional vegetation indices, potentially provide better estimates of the photosynthetic activity within a canopy-and therefore canopy primary production-specifically as a function of Sun and view angles. RP RONDEAUX, G (reprint author), NASA, AMES RES CTR, MAIL STOP 242-4, MOFFETT FIELD, CA 94035 USA. NR 25 TC 6 Z9 6 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUN PY 1993 VL 14 IS 9 BP 1815 EP 1823 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA LR589 UT WOS:A1993LR58900014 ER PT J AU FERRANDO, AA GREEN, NR AF FERRANDO, AA GREEN, NR TI THE EFFECT OF BORON SUPPLEMENTATION ON LEAN BODY-MASS, PLASMA TESTOSTERONE LEVELS, AND STRENGTH IN MALE BODYBUILDERS SO INTERNATIONAL JOURNAL OF SPORT NUTRITION LA English DT Article DE TOTAL TESTOSTERONE; FREE TESTOSTERONE; 1-RM; SQUAT; BENCH PRESS AB The effect of boron supplementation was investigated in 19 male bodybuilders, ages 20-27 years. Ten were given a 2.5-mg boron supplement while 9 were given a placebo every day for 7 weeks. Plasma total and free testosterone, plasma boron, lean body mass, and strength measurements were determined on Days 1 and 49 of the study. Plasma boron values were significantly (p<0.05) different as the experimental group increased from (+/- SD) 20.1 +/- 7.7 ppb pretest to 32.6 +/- 27.6 ppb posttest, while the control group mean decreased from 15.1 +/- 14.4 ppb pretest to 6.3 +/- 5.5 ppb posttest. Analysis of variance indicated no significant effect of boron supplementation on any of the dependent variables. Both groups demonstrated significant increases in total testosterone, lean body mass, 1-RM squat, and 1-RM bench press. The findings suggest that 7 weeks of bodybuilding can increase total testosterone, lean body mass, and strength in lesser trained bodybuilders, and that boron supplementation had no effect on these measures. RP FERRANDO, AA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SD 4,NASA RD 1,HOUSTON,TX 77058, USA. NR 0 TC 16 Z9 17 U1 0 U2 1 PU HUMAN KINETICS PUBL INC PI CHAMPAIGN PA 1607 N MARKET ST, CHAMPAIGN, IL 61820-2200 SN 1050-1606 J9 INT J SPORT NUTR JI Int. J. Sport Nutr. PD JUN PY 1993 VL 3 IS 2 BP 140 EP 149 PG 10 WC Nutrition & Dietetics; Sport Sciences SC Nutrition & Dietetics; Sport Sciences GA LD693 UT WOS:A1993LD69300002 PM 8508192 ER PT J AU GAWRONSKI, W HADAEGH, FY AF GAWRONSKI, W HADAEGH, FY TI BALANCED INPUT-OUTPUT ASSIGNMENT SO INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE LA English DT Article AB A method of actuator/sensor location is presented. The state space representation obtained has assigned controllability and observability properties. The assignability conditions are defined, and algorithms for determining sensor and/or actuator locations are derived. The results are specified for systems with properties of flexible structures. RP GAWRONSKI, W (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 6 TC 4 Z9 4 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0020-7721 J9 INT J SYST SCI JI Int. J. Syst. Sci. PD JUN PY 1993 VL 24 IS 6 BP 1027 EP 1036 DI 10.1080/00207729308949541 PG 10 WC Automation & Control Systems; Computer Science, Theory & Methods; Operations Research & Management Science SC Automation & Control Systems; Computer Science; Operations Research & Management Science GA LG539 UT WOS:A1993LG53900002 ER PT J AU CHANG, ATC BARNES, A GLASS, M KAKAR, R WILHEIT, TT AF CHANG, ATC BARNES, A GLASS, M KAKAR, R WILHEIT, TT TI AIRCRAFT OBSERVATIONS OF THE VERTICAL STRUCTURE OF STRATIFORM PRECIPITATION RELEVANT TO MICROWAVE RADIATIVE-TRANSFER SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RAIN AB The retrieval of rainfall intensity over the oceans from passive microwave observations is based on a radiative transfer model. Direct rainfall observations of oceanic rainfall are virtually nonexistant making validation of the retrievals extremely difficult. Observations of the model assumptions provide an alternative approach for improving and developing confidence in the rainfall retrievals. In the winter of 1983, the NASA CV-990 aircraft was equipped with a payload suitable for examining several of the model assumptions. The payload included microwave and infrared radiometers, mirror hygrometers, temperature probes, and PMS probes. On two occasions the aircraft ascended on a spiral track through stratiform precipitation providing an opportunity to study the atmospheric parameters. The assumptions concerning liquid hydrometeors, water vapor, lapse rate, and non-precipitating clouds were studied. Model assumptions seem to be supported by these observations. C1 PHILLIPS LAB, BEDFORD, MA USA. NASA HEADQUARTERS, OFF SPACE SCI & APPLICAT, WASHINGTON, DC USA. TEXAS A&M UNIV SYST, DEPT METEOROL, COLL STN, TX 77843 USA. RP CHANG, ATC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HYDROL SCI BRANCH, CODE 974, GREENBELT, MD 20771 USA. RI Wilheit, Thomas/G-9438-2012 NR 22 TC 9 Z9 10 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 1993 VL 32 IS 6 BP 1083 EP 1091 DI 10.1175/1520-0450(1993)032<1083:AOOTVS>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LF076 UT WOS:A1993LF07600005 ER PT J AU MARKS, FD ATLAS, D WILLIS, PT AF MARKS, FD ATLAS, D WILLIS, PT TI PROBABILITY-MATCHED REFLECTIVITY RAINFALL RELATIONS FOR A HURRICANE FROM AIRCRAFT OBSERVATIONS SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CONVECTIVE RAINFALL; AREA INTEGRALS; RADAR AB The probability-matching method (PMM) was used to determine the relation between the distribution of equivalent reflectivity Z(e) measured by an airborne C-band radar and that for concurrently measured rain rate R by a disdrometer on the same aircraft in the eyewall and outer bands of Hurricane Anita in 1977. When the PMM is applied to the disdrometer population of Z's and R's one finds that the Z-R relations differ significantly from those obtained by linear regression of their logarithms. Such regression relations are deceptive. When PMM is applied to the set of Z(e)'s and R's we get a family of Z(e)-R relations as a function of range which differ significantly from the traditional disdrometer-based Z-R relation for hurricanes by Jorgensen and Willis (JW). These new relations are approximate power laws with slope (exponent) which decrease with increasing range. At ranges less than about 35 km the reflectivity in the eyewall exceeds that in the outer bands and is consistent with the expectation from the disdrometer-based relations. At greater ranges the converse is true due to beamwidth averaging over a broader beam and different vertical profiles of reflectivity in the eyewall and outer bands. We also devise a method to obtain an ''effective zero-range'' Z(e)-R relation. This differs from the JW relation by -8.2 dBZ and reflects an error in the radar calibration. This approach is a novel way to calibrate an airborne meteorological radar. The methods may be used with any type of rainstorms and provide a means of using airborne radar and disdrometer systems for air-truthing rainfall measurements from space. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP MARKS, FD (reprint author), NOAA,AOML,DIV HURRICANE RES,4301 RICKENBACKER CAUSEWAY,MIAMI,FL 33149, USA. RI Marks, Frank/A-5733-2011; Willis, Paul/I-7034-2013 OI Marks, Frank/0000-0003-0371-5514; Willis, Paul/0000-0003-4506-9813 NR 20 TC 10 Z9 10 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUN PY 1993 VL 32 IS 6 BP 1134 EP 1141 DI 10.1175/1520-0450(1993)032<1134:PMRRRF>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LF076 UT WOS:A1993LF07600009 ER PT J AU ARATOW, M BALLARD, RE CRENSHAW, AG STYF, J WATENPAUGH, DE KAHAN, NJ HARGENS, AR AF ARATOW, M BALLARD, RE CRENSHAW, AG STYF, J WATENPAUGH, DE KAHAN, NJ HARGENS, AR TI INTRAMUSCULAR PRESSURE AND ELECTROMYOGRAPHY AS INDEXES OF FORCE DURING ISOKINETIC EXERCISE SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE ECCENTRIC; CONCENTRIC; MUSCLE FORCE; BIOMECHANICAL MODELS ID SKELETAL-MUSCLE; EMG; CONTRACTIONS; PERFORMANCE; SURFACE; SIGNAL AB A direct method for measuring force production of specific muscles during dynamic exercise is presently unavailable. Previous studies indicate that both intramuscular pressure (IMP) and electromyography (EMG) correlate linearly with muscle contraction force during isometric exercise. The objective of this study was to compare IMP and EMG as linear assessors of muscle contraction force during dynamic exercise. IMP and surface EMG activity were recorded during concentric and eccentric isokinetic plantarflexion and dorsiflexion of the ankle joint from the tibialis anterior (TA) and soleus (SOL) muscles of nine male volunteers (28-54 yr). Ankle torque was measured using a dynamometer, and IMP was measured via catheterization. IMP exhibited better linear correlation than EMG with ankle joint torque during concentric contractions of the SOL (IMP R2 = 0.97, EMG R2 = 0.81) and the TA (IMP R2 = 0.97, EMG R2 = 0.90), as well as during eccentric contractions (SOL: IMP R2 = 0.91, EMG R2 = 0.51; TA: IMP R2 = 0.94, EMG R2 = 0.73). IMP provides a better index of muscle contraction force than EMG during concentric and eccentric exercise through the entire range of torque. IMP reflects intrinsic mechanical properties of individual muscles, such as length-tension relationships, which EMG is unable to assess. C1 NASA,AMES RES CTR,DIV LIFE SCI 239 11,MOFFETT FIELD,CA 94035. NR 24 TC 69 Z9 69 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 1993 VL 74 IS 6 BP 2634 EP 2640 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA LL820 UT WOS:A1993LL82000004 PM 8365963 ER PT J AU ARATOW, M FORTNEY, SM WATENPAUGH, DE CRENSHAW, AG HARGENS, AR AF ARATOW, M FORTNEY, SM WATENPAUGH, DE CRENSHAW, AG HARGENS, AR TI TRANSCAPILLARY FLUID RESPONSES TO LOWER-BODY NEGATIVE-PRESSURE SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE SUBCUTANEOUS FLUID PRESSURE; INTRAMUSCULAR FLUID PRESSURE; STARLING FORCES; PLASMA VOLUME; MICROGRAVITY COUNTERMEASURES ID SKELETAL-MUSCLE; BLOOD-VOLUME; ABSORPTION; STRESS; ATRIAL AB The effect of lower body negative pressure (LBNP) on transcapillary fluid balance is unknown. Therefore, our objective was to assess leg interstitial fluid pressures (IFP), leg circumference, plasma volume (PV), and net whole body transcapillary fluid transport (TFT) during and after supine LBNP and to evaluate the addition of oral saline ingestion on transcapillary exchange. Six healthy men 23-41 yr old underwent 4 h of 30 mmHg LBNP, followed by 50 min of supine recovery on two separate occasions, once with and once without ingestion of 1 liter of isotonic saline. IFP was measured continuously in subcutis as well as superficial and deep regions of the tibialis anterior muscle by slit catheters. TFT was calculated by subtracting urine production and calculated insensible fluid loss from changes in PV. During exposure to LBNP, IFP decreased in parallel with chamber pressure, foot venous pressure did not change, leg circumference increased by 3 +/- 0.35% (SE) (P < 0.05), and PV decreased by 14 +/- 2.3%. IFP returned to near control levels after LBNP. At the end of minute 50 of recovery, PV remained decreased (by 7.5 +/- 5.2%) and leg circumference remained elevated (by 1 +/- 0.37%). LBNP alone produced significant movement of fluid into the lower body but no net TFT (-7 +/- 12 ml/h). During LBNP with saline ingestion, 72 +/- 4% of the ingested fluid volume filtered out of the vascular space (TFT = 145 +/- 10 ml/h), and PV decreased by 6 +/- 3%. Post-LBNP IFP and leg circumference tended to increase more with saline ingestion than without saline, but these differences were not significant. In addition, PV returned to baseline values at minute 50 of recovery. Thus, prolonged LBNP, especially with saline ingestion, promotes fluid filtration into lower body tissues. C1 NASA,AMES RES CTR,DIV LIFE SCI 239 11,MOFFETT FIELD,CA 94035. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 38 TC 42 Z9 43 U1 0 U2 2 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 1993 VL 74 IS 6 BP 2763 EP 2770 PG 8 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA LL820 UT WOS:A1993LL82000023 PM 8365979 ER PT J AU KAWAI, Y MURTHY, G WATENPAUGH, DE BREIT, GA DEROSHIA, CW HARGENS, AR AF KAWAI, Y MURTHY, G WATENPAUGH, DE BREIT, GA DEROSHIA, CW HARGENS, AR TI CEREBRAL BLOOD-FLOW VELOCITY IN HUMANS EXPOSED TO 24-H OF HEAD-DOWN TILT SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE AUTOREGULATION; CEREBRAL CIRCULATION; INTRACRANIAL PRESSURE; MICROGRAVITY; ORTHOSTATIC INTOLERANCE; TRANSCRANIAL DOPPLER ULTRASONOGRAPHY ID CARDIOVASCULAR ADAPTATION; SIMULATED WEIGHTLESSNESS; TRANSCRANIAL DOPPLER; FLUID SHIFTS; ZERO GRAVITY; SPACE; HYPOTENSION; RESPONSES; ARTERIES; PRESSURE AB This study investigates cerebral blood flow (CBF) velocity in humans before, during, and after 24 h of 6-degrees head-down tilt (HDT), which is a currently accepted experimental model to simulate microgravity. CBF velocity was measured by use of the transcranial Doppler technique in the right middle cerebral artery of eight healthy male subjects. Mean CBF velocity increased from the pre-HDT upright seated baseline value of 55.5 +/- 3.7 (SE) cm/s to 61.5 +/- 3.3 cm/s at 0.5 h of HDT (P < 0.05), reached a peak value of 63.2 +/- 4.1 cm/s at 3 h of HDT, and remained significantly above the pre-HDT baseline for greater-than-or-equal-to 6 h of HDT. During upright seated recovery (1-5 h post-HDT), mean CBF velocity decreased to 87% of the pre-HDT baseline value (P < 0.05). Mean CBF velocity correlated well with calculated intracranial arterial pressure (IAP) (r = 0.54, P < 0.001). As analyzed by linear regression, mean CBF velocity = 29.6 + 0.32IAP. These results suggest that HDT increases CBF velocity by increasing IAP during several hours after the onset of microgravity. Importantly, the decrease in CBF velocity after HDT may be responsible, in part, for the increased risk of syncope observed in subjects after prolonged bed rest and also in astronauts returning to Earth. C1 NASA,AMES RES CTR,DIV LIFE SCI 23911,MOFFETT FIELD,CA 94035. NR 34 TC 53 Z9 55 U1 1 U2 4 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 1993 VL 74 IS 6 BP 3046 EP 3051 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA LL820 UT WOS:A1993LL82000061 PM 8366006 ER PT J AU GELLER, MA CHI, YC ROOD, RB DOUGLASS, AR KAYE, JA ALLEN, DJ AF GELLER, MA CHI, YC ROOD, RB DOUGLASS, AR KAYE, JA ALLEN, DJ TI SATELLITE OBSERVATION AND MAPPING OF WINTERTIME OZONE VARIABILITY IN THE LOWER STRATOSPHERE SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article AB Comparison is made between 30 mbar ozone fields that are generated by a transport-chemistry model utilizing the winds from the Goddard Space Flight Center stratospheric data assimilation system (STRATAN), observations from the LIMS instrument on Nimbus 7, and the ozone fields that result from 'flying' a mathematical simulation of LIMS observations through the transport-chemistry model ozone fields. The modeled ozone fields are found to resemble the LIMS observations, but the model fields show much more temporal and spatial structure than do the LIMS observations. The 'satellite-mapped' model results resemble the LIMS observations much more closely. These results are very consistent with the earlier discussions of satellite space-time sampling by Salby. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHER CHEM & DYNAM BRANCH,GREENBELT,MD 20771. APPL RES CORP,LANDOVER,MD. RP GELLER, MA (reprint author), SUNY STONY BROOK,INST TERR & PLANETARY ATMOSPHERES,STONY BROOK,NY 11794, USA. RI Allen, Dale/F-7168-2010; Douglass, Anne/D-4655-2012; Rood, Richard/C-5611-2008 OI Allen, Dale/0000-0003-3305-9669; Rood, Richard/0000-0002-2310-4262 NR 16 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD JUN PY 1993 VL 55 IS 7 BP 1081 EP 1088 DI 10.1016/0021-9169(93)90099-K PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA KY043 UT WOS:A1993KY04300014 ER PT J AU MCPHERRON, RL BAKER, DN AF MCPHERRON, RL BAKER, DN TI FACTORS INFLUENCING THE INTENSITY OF MAGNETOSPHERIC SUBSTORMS SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT TOPICAL SYMP ON MAGNETOSPHERIC PHENOMENA, AT THE 20TH GENERAL ASSEMBLY OF THE INTERNATIONAL UNION OF GEODESY AND GEOPHYSICS CY AUG, 1991 CL VIENNA, AUSTRIA SP INT UNION GEODESY & GEOPHYS ID INTERPLANETARY MAGNETIC-FIELD; HIGH TIME RESOLUTION; SOLAR-WIND CONTROL; GEOMAGNETIC-ACTIVITY; AURORAL ELECTROJET; CURRENT-SYSTEMS; PARAMETER CORRELATIONS; MAGNETOMETER DATA; GROWTH PHASE; ENERGY FLUX AB A magnetospheric substorm is the sequence of processes which occur throughout the magnetosphere following a southward turning of the interplanetary magnetic field and the onset of dayside reconnection. An isolated substorm consists of three phases, growth, expansion and recovery. Two primary processes make up a substorm. The directly driven component visible in the global, two cell current system is powered by the direct projection of the solar wind electric field onto the conducting ionosphere. The unloading component seen as the one cell intensification of the westward electrojet near midnight is powered by processes internal to the plasma sheet. The intensity of substorms can be measured by a variety of activity indices, the most common of which are magnetic indices. The solar wind controls the intensity of substorms through the process of magnetic reconnection. Time series analysis has established that 40 min after a southward turning of the interplanetary magnetic field the strength of the electrojets is correlated with solar wind parameters through a nonlinear coupling function similar to V2B Sin4(theta/2) (where theta = IMF clock angle about Sun vector). Linear filter analysis of the magnetospheric system response shows that the average impulse response for the AL index is a Rayleigh function peaking at a lag time of 60 min and diminishing to zero after 3 h. The average response function for a sequence of moderate substorms is bimodal with peaks at 25 and 70 min, while more intense activity is uni-modal with only the 25 min peak. Response functions for individual substorms have peak amplitudes and delays that can be substantially different from the average. The linear analysis predicts less than half the variance in the AL index when high resolution indices are used. These results imply that reconnection on the day and night side are delayed relative to the solar wind by differing amounts which vary with conditions in the solar wind, magnetosphere, and ionosphere. Currents are driven through the ionosphere that are proportional to the reconnection rates which are in turn proportional to the solar wind electric field, but their strength depends on ionospheric conductivity. Conductivity depends on season, prior activity, and the way in which a particular substorm develops. Computer simulation of substorms with a simple 'leaky tap' model suggests that one reason for lack of short term predictabilty is likely to be that the magnetosphere is nonlinear with behavior depending both on previous conditions and the strength and wave form of the solar wind input. New techniques of analysis of magnetic indices support this conjecture. As with the Earth's surface weather, accurate space weather predictions will probably require extensive real-time observatory networks both in the solar wind and magnetosphere. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP MCPHERRON, RL (reprint author), UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024, USA. NR 125 TC 22 Z9 22 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD JUN PY 1993 VL 55 IS 8 BP 1091 EP 1122 DI 10.1016/0021-9169(93)90040-6 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LF104 UT WOS:A1993LF10400002 ER PT J AU FROST, SJ WHITSON, PA AF FROST, SJ WHITSON, PA TI CHARACTERIZATION OF ATRIAL-NATRIURETIC-PEPTIDE DEGRADATION BY CELL-SURFACE PEPTIDASE ACTIVITY ON ENDOTHELIAL-CELLS SO JOURNAL OF CELLULAR BIOCHEMISTRY LA English DT Article DE PROTEOLYSIS; ANP; CPA47; VASOACTIVE PEPTIDES; CLEARANCE ID RECEPTOR-MEDIATED ENDOCYTOSIS; COOH-TERMINAL TRIPEPTIDE; CLEARANCE FUNCTION; C RECEPTORS; ENDOPEPTIDASE-24.11; HYDROLYSIS; KALLIKREIN; CATABOLISM; METABOLISM; MEMBRANES AB Atrial natriuretic peptide (ANP) is a fluid-regulating peptide hormone that promotes vasorelaxation, natriuresis, and diuresis. The mechanisms for the release of ANP and for its clearance from the circulation play important roles in modulating its biological effects. Recently, we have reported that the cell surface of an endothelial cell line, CPA47, could degrade I-125-ANP in the presence of EDTA. In this study, we have characterized this degradation of I-125-ANP. The kinetics of ANP degradation by the surface of CPA47 cells were first order, with a K(m) of 320 +/- 60 nM and V(max) of 35 +/- 14 pmol of ANP degraded/10 min/10(5) cells at pH 7.4. ANP is degraded by the surface of CPA47 cells over a broad pH range from 7.0-8.5. Potato carboxypeptidase inhibitor and bestatin inhibited I-125-ANP degradation, suggesting that this degradative activity on the surface of CPA47 cells has exopeptidase characteristics. The selectivity of CPA47 cell-surface degradation of ANP was demonstrated when I-125-ANP degradation was inhibited in the presence of neuropeptide Y and angiotensin I and II but not bradykinin, bombesin, endothelin-1, or substance P. The C-terminal amino acids phe26 and tyr28 were deduced to be important for ANP interaction with the cell-surface peptidase(s) based on comparison of the IC50 of various ANP analogues and other natriuretic peptides for the inhibition of ANP degradation. These data suggest that a newly characterized divalent cation-independent exopeptidase(s) that selectively recognizes ANP and some other vasoactive peptides exists on the surface of endothelial cells. C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,MAIL CODE SD4,HOUSTON,TX 77058. NR 31 TC 5 Z9 5 U1 0 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0730-2312 J9 J CELL BIOCHEM JI J. Cell. Biochem. PD JUN PY 1993 VL 52 IS 2 BP 227 EP 236 DI 10.1002/jcb.240520214 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA LF871 UT WOS:A1993LF87100013 PM 8366138 ER PT J AU BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H AF BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H TI THEORETICAL-STUDY OF THE LOWEST 5-PI AND 5-SIGMA+ STATES OF CO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION AB The lowest 5PI and 5SIGMA+ states of CO are characterized using very large one-particle basis sets and the internally contracted multireference configuration-interaction treatment of electron correlation. It is found that the (1) 5SIGMA+ state is weakly bound (D(e)=572 cm-1) with an r(e) of 4.76 a0, in good agreement with earlier theoretical calculations by Rosenkrantz et al. [Theor. Chim. Acta 82, 153 (1992)]. The (1)5PI state (hereafter designated a'' 5PI ) has a weakly bound outer well (D(e)=18 cm-1, r(e)=5.80 a0) and a significantly bound inner well (D(e)=6043 cm-1 r(e)=2.76 a0). It is shown that the emission spectrum between about 360 and 520 nm observed by Bahrdt et al. [Chem. Phys. 144, 273 (1990)] can be assigned to the a'' 5PI-a' 3SIGMA+ and a'' 5PI -d3DELTA transitions. Franck-Condon factors are presented to aid in the experimental identification of the a'' 5PI state by absorption from the low-lying triplet states of CO. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 15 TC 11 Z9 11 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1993 VL 98 IS 11 BP 8785 EP 8789 DI 10.1063/1.464487 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LE412 UT WOS:A1993LE41200048 ER PT J AU SPENCER, RW CHRISTY, JR AF SPENCER, RW CHRISTY, JR TI PRECISION LOWER STRATOSPHERIC TEMPERATURE MONITORING WITH THE MSU - TECHNIQUE, VALIDATION, AND RESULTS 1979-1991 SO JOURNAL OF CLIMATE LA English DT Article ID CHICHON VOLCANIC-ERUPTION; EL-CHICHON; CLIMATE; MEXICO; MODEL AB Microwave Sounding Unit channel 4 data from the TIROS-N series of NOAA satellites are intercalibrated to provide a continuous global record of deep-layer averaged lower stratospheric temperatures during 1979-1991. A 13-year record of temperature anomalies is time averaged into pentads and months on a 2.5-degrees grid. The monthly gridpoint anomalies are validated with ten years of radiosonde data during 1979-88. The calibration stability of each satellite's measurements is evaluated during satellite overlap periods, the longest of which reveal no measurable instrumental drift at the level of 0.01-degrees-C yr-1. Intercomparisons between NOAA-6 and NOAA-7 anomalies indicate monthly gridpoint precision of 0.05-degrees-C in the tropics to around 0.10-degrees-C in the extratropics, and signal-to-noise ratios generally over 500, while global monthly precision is 0.01-degrees to 0.02-degrees-C These precision and stability statistics are much better than have been previously reported by other investigators for MSU channel 4. Pentad precision is about 0. 10-degrees-C in the tropics to around 0.25-degrees-C at high latitudes and signal-to-noise ratios generally over 250 in the tropics and high latitudes, but 100-200 in the middle latitudes. Radiosonde comparisons to the monthly gridpoint anomalies have correlations ranging from 0.90 in the tropics (where the interannual variability is smallest) to as high as 0.99 at high-latitude stations. The corresponding standard error of estimate is generally around 0.3-degrees-C. A significant difference in decadal trends is found between the satellite and radiosonde systems, with a step change of 0.21-degrees-C (sondes cooler) compared to the satellite measurements. Investigations of the possible sources of the discrepancy lead us to suspect that the gradual transition from on-site calibration of sondes with thermometers to factory calibration of sondes around 1982 might have caused a change in the calibration, although this conclusion must be viewed as tentative. The largest globally averaged temperature variations during 1979-91 occur after the El Chichon ( 1982) and Pinatubo ( 199 1 ) volcanic eruptions. These warm events are superimposed upon a net downward trend in temperatures during the period. This cooling trend has more of a step function than linear character, with the step occurring during the El Chichon warm event. It is strongest in polar regions and the Northern Hemisphere middle latitudes. These characteristics are qualitatively consistent with radiative adjustments expected to occur with observed ozone depletions. C1 UNIV ALABAMA,ATMOSPHER SCI PROGRAM,HUNTSVILLE,AL 35899. RP SPENCER, RW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV EARTH SCI & APPLICAT,CODE E543,HUNTSVILLE,AL 35812, USA. NR 27 TC 77 Z9 77 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN PY 1993 VL 6 IS 6 BP 1194 EP 1204 DI 10.1175/1520-0442(1993)006<1194:PLSTMW>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LK397 UT WOS:A1993LK39700017 ER PT J AU HALPERN, D JI, M AF HALPERN, D JI, M TI AN EVALUATION OF THE NATIONAL METEOROLOGICAL CENTER WEEKLY HINDCAST OF UPPER-OCEAN TEMPERATURE ALONG THE EASTERN PACIFIC EQUATOR IN JANUARY 1992 SO JOURNAL OF CLIMATE LA English DT Note ID TROPICAL PACIFIC; EL NINO AB The upper-ocean temperature distribution along the Pacific equator from 139-degrees to 103-degrees-W was observed in January 1992 with temperature profiles recorded from a ship and inferred from an ocean general circulation model calculation involving data assimilation (i.e., hindcast). An El Nino episode was in progress. The 100-m-thick mixed layer depth, the mixed-layer temperature, and the depth-averaged temperature below the thermocline were similar in both data products. Considerable differences occurred in the representation of the 15-degrees-25-degrees-C thermocline, such as the depth-averaged temperatures above and below the 20-degrees-C isotherm, the east-west slope of the 20-degrees-C isotherm, and a 1000-km-wide depression. The longitudinal-averaged root-mean-square difference between the hindcast and observed depths of the center of the thermocline was 17 m. Most of the disparities could be attributed to a high wavenumber transient event that the model-based assimilation system was not intended to resolve. C1 NOAA,NATL WEATHER SERV,NATL METEOROL CTR,COUPLED MODEL PROJECT,WASHINGTON,DC 20233. RP HALPERN, D (reprint author), JET PROP LAB,DEPT EARTH & SPACE SCI,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 6 Z9 6 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN PY 1993 VL 6 IS 6 BP 1221 EP 1226 DI 10.1175/1520-0442(1993)006<1221:AEOTNM>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LK397 UT WOS:A1993LK39700019 ER PT J AU LATHERS, CM RIDDLE, JM MULVAGH, SL MUKAI, C DIAMANDIS, PH DUSSACK, LG BUNGO, MW CHARLES, JB AF LATHERS, CM RIDDLE, JM MULVAGH, SL MUKAI, C DIAMANDIS, PH DUSSACK, LG BUNGO, MW CHARLES, JB TI ECHOCARDIOGRAMS DURING 6 HOURS OF BEDREST AT HEAD-DOWN AND HEAD-UP TILT AND DURING SPACE-FLIGHT SO JOURNAL OF CLINICAL PHARMACOLOGY LA English DT Article ID EARLY CARDIOVASCULAR ADAPTATION; ZERO GRAVITY; VOLUME AB Left ventricular end-diastolic volume increased after 4 1/2 to 6 hours of space flight, but was significantly decreased after 5 to 6 days of space flight. To determine the role of acute gravitational effects in this phenomenon, responses to a 6-hour bedrest model of 0 gravity (G; 5-degrees head-down tilt) were compared with those of fractional gravity loads of 1/6G, 1/3G, and 2/3G by using head-up tilts of 10-degrees, 20-degrees, and 42-degrees, respectively. On 4 different days, six healthy male subjects were tilted at one of the four angles for 6 hours. Cardiac dimensions and volumes were determined from two-dimensional and M-mode echocardiograms in the left lateral decubitus position at control (0), 2, 4, and 6 hours. Stroke volume decreased with time (P <.05) for all tilt angles when compared with control. Ejection fraction (EF) at -5-degrees was greater than at +20-degrees and +42-degrees (not significant); EF at +100 was greater than at +420 (not significant). For the tilt angles of -5-degrees, +10-degrees, and +20-degrees, mean heart rate decreased during the first 2 hours, and returned to control or was slightly elevated above control (+20-degrees) by 6 hours (not significant). At the +42-degrees angle of tilt, heart rate was increased above control at hours 2, 4, and 6. There were no significant differences in cardiac output at any time point for any tilt angle. Left ventricular end-diastolic volume did not change significantly with time or tilt angle, but there was a trend to a decrease by hour 2. Left ventricular end-systolic volume was increased at hour 2 (not significant) and at hour 4 (not significant) for subjects at -5-degrees. Systolic blood pressure did not change significantly. Left ventricular end-diastolic volume, left ventricular end-systolic volume, stroke volume, ejection fraction, heart rate, and cardiac output were at control values by hour 6 for all tilt angles. The lack of a significant immediate change in left ventricular end-diastolic volume despite decrements in stroke volume (P < .05) and heart rate (not significant) suggests that multiple factors may play a role in the adaptation to simulated hypogravity. The data indicate that no angle of tilt, whether head-down or head-up for 4 to 6 hours, mimicked exactly the changes in cardiovascular function recorded after 4 to 6 hours of flight. Thus space and bedrest changes in left ventricular end-diastolic volume may be similar but possess a different time course. Nevertheless, head-down tilt at 5-degrees for 6 hours mimics some (stroke volume, systolic and diastolic blood pressure, mean arterial blood pressure, total peripheral vascular resistance), but not all, of the changes occurring in an equivalent time of space flight. C1 UNIV SPACE RES ASSOC,DIV SPACE BIOMED,HOUSTON,TX. KRUG INT,HOUSTON,TX. KN NASDA,HOUSTON,TX. MIT,DEPT AERONAUT & ASTRONAUT,CAMBRIDGE,MA 02139. HARVARD UNIV,SCH MED,BOSTON,MA 02115. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 26 TC 11 Z9 11 U1 0 U2 3 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0091-2700 J9 J CLIN PHARMACOL JI J. Clin. Pharmacol. PD JUN PY 1993 VL 33 IS 6 BP 535 EP 543 PG 9 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA LG396 UT WOS:A1993LG39600008 PM 8366179 ER PT J AU SALPEKAR, SA OBRIEN, TK AF SALPEKAR, SA OBRIEN, TK TI ANALYSIS OF MATRIX CRACKING AND LOCAL DELAMINATION IN (O/THETA/-THETA)S GRAPHITE-EPOXY LAMINATES UNDER TENSILE LOAD SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE MATRIX CRACK; DELAMINATION; LAMINATE; COMPOSITE; FINITE ELEMENT ANALYSIS; GRAPHITE EPOXY AB Several three-dimensional element analyses of (0/theta/ - theta)s graphite epoxy laminates, where theta = 15, 20, 25, 30, and 45-degrees, subjected to axial tensile load, were performed. The interlaminar stresses in the theta/ - theta interface were calculated with and without a matrix crack in the central - theta plies. The interlaminar normal stress changes from a small compressive stress when no matrix crack is present to a high tensile stress at the intersection of the matrix crack and the free edge. The analysis of local delamination from the - theta matrix crack indicates a high strain energy release rate and a localized Mode I component near the free edge, within one-ply distance from the matrix crack. To examine the stress state causing the matrix cracking, the maximum principal normal stress in a plane perpendicular to the fiber direction in the - theta ply was calculated in an uncracked laminate. The corresponding shear stress parallel to the fiber was also calculated. The principal normal stress at the laminate edge increased through the ply thickness and reached a very high tensile value at the theta/ - theta interface indicating that the crack in the - theta ply may initiate at the theta/ - theta interface. Predicted crack profiles on the laminate edge in the - theta ply were constructed from the principal stress directions. The cracks were found to be more curved for layups with smaller theta angles, which is consistent with experimental observations in the literature. C1 NASA,LANGLEY RES CTR,USA VEHICLE STRUCT DIRECTORATE,HAMPTON,VA 23665. RP SALPEKAR, SA (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23681, USA. NR 9 TC 14 Z9 14 U1 0 U2 3 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD SUM PY 1993 VL 15 IS 2 BP 95 EP 100 PG 6 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA LK559 UT WOS:A1993LK55900003 ER PT J AU MASTERS, JE FOYE, RL PASTORE, CM GOWAYED, YA AF MASTERS, JE FOYE, RL PASTORE, CM GOWAYED, YA TI MECHANICAL-PROPERTIES OF TRIAXIALLY BRAIDED COMPOSITES - EXPERIMENTAL AND ANALYTICAL RESULTS SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE TEXTILE-REINFORCED COMPOSITES; TRIAXIALLY BRAID; UNIT CELL; STIFFNESS; STRENGTH; POISSONS RATIO; LAMINATED PLATE THEORY; FIBER WAVINESS; DIAGONAL BRICK ANALYSIS; FINITE ELEMENT ANALYSIS AB This paper investigates the unnotched tensile properties of two-dimensional (2-D) triaxial braid-reinforced composites from both an experimental and an analytical viewpoint. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded composite panels made from each braid. There were considerable differences in the observed elastic constants from different size strain gage and extensometer readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0-degrees, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement, but none adequately matched the experimental results for all the braids. C1 N CAROLINA AGR & TECH STATE UNIV,DEPT MECH ENGN,GREENSBORO,NC 27411. N CAROLINA STATE UNIV,DEPT TEXT ENGN CHEM & SCI,RALEIGH,NC 27695. AUBURN UNIV,DEPT TEXT ENGN,AUBURN,AL 36849. RP MASTERS, JE (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 188E,HAMPTON,VA 23681, USA. NR 5 TC 53 Z9 62 U1 1 U2 7 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD SUM PY 1993 VL 15 IS 2 BP 112 EP 122 PG 11 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA LK559 UT WOS:A1993LK55900005 ER PT J AU JAIN, A VAIDEHI, N RODRIGUEZ, G AF JAIN, A VAIDEHI, N RODRIGUEZ, G TI A FAST RECURSIVE ALGORITHM FOR MOLECULAR-DYNAMICS SIMULATION SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID BODIES C1 CALTECH,ARTHUR AMOS NOYES LAB CHEM PHYS,PASADENA,CA 91125. RP JAIN, A (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 21 TC 140 Z9 140 U1 0 U2 11 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN PY 1993 VL 106 IS 2 BP 258 EP 268 PG 11 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA LD949 UT WOS:A1993LD94900004 ER PT J AU SHUEN, JS CHEN, KH CHOI, YH AF SHUEN, JS CHEN, KH CHOI, YH TI A COUPLED IMPLICIT METHOD FOR CHEMICAL NONEQUILIBRIUM FLOWS AT ALL SPEEDS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID NAVIER-STOKES EQUATIONS; JETS C1 UNIV TOLEDO,NASA,LEWIS RES CTR,TOLEDO,OH 43606. RP SHUEN, JS (reprint author), NASA,LEWIS RES CTR,SVERDRUP TECHNOL INC,CLEVELAND,OH 44135, USA. NR 26 TC 66 Z9 71 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN PY 1993 VL 106 IS 2 BP 306 EP 318 PG 13 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA LD949 UT WOS:A1993LD94900008 ER PT J AU CURRERI, PA RAMACHANDRAN, N DOWNEY, JP JONES, JC AF CURRERI, PA RAMACHANDRAN, N DOWNEY, JP JONES, JC TI NUMERICAL MODELING OF MELT VELOCITY AND THERMAL DISTRIBUTIONS DURING AIRCRAFT HIGH-GRAVITY ARCS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID CRYSTAL-GROWTH; CENTRIFUGE AB Centrifuge crystal growth experiments under 2-6 gravity have produced crystals with microstructure indicative of diffusion controlled growth. A current hypothesis for this phenomenon is that Coriolis and gravity gradient forces produced by the centrifugal motion can effectively damp convective flows. Our research has included the study of solidification during KC-135 aircraft parabolic maneuvers which produce alternate periods of 25 s low gravity and 45 s of high (1.8g0) gravity. We, thus, examined the question of how the Coriolis and gravity gradient forces during high gravity maneuvers compare to that for common centrifuges. Microstructural examination of samples solidified during high gravity arcs has revealed no evidence of convection dampening. As a first approximation, we model the high gravity arc as a centrifuge with radius of 20,480 ft and angular speed of 0.318 rpm. Scaling analysis indicates that the Coriolis and gravity gradient expected on the aircraft high gravity arc are less than that for the centrifuges by a factor of 100. Detailed Navier-Stokes analysis of the fluid flow and thermal fields during solidification of aluminum and Cd-Te in KC-135 high gravity show that convective flows of about 1 mm/s are induced. The thermal field, however, is only slightly modified by the convection. Coriolis and gravity gradient during solidification in KC-135 high gravity arcs, even at accelerations that have been shown to produce significant convective flow dampening in some centrifuge systems, are shown to have no significant influence on the melt thermal and flow fields. The KC-135 high gravity arc could, thus, be advantageously utilized for experiments where separation of centrifugal acceleration and Coriolis acceleration is desirable. C1 UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35806. WYLE LABS,HUNTSVILLE,AL 35807. RP CURRERI, PA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 14 TC 0 Z9 0 U1 0 U2 1 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 JUN PY 1993 VL 130 IS 3-4 BP 511 EP 522 DI 10.1016/0022-0248(93)90540-D PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA LK453 UT WOS:A1993LK45300021 ER PT J AU PINES, V ZLATKOWSKI, M CHAIT, A AF PINES, V ZLATKOWSKI, M CHAIT, A TI SOLITARY WAVE GENERATION DURING SOLIDIFICATION SO JOURNAL OF CRYSTAL GROWTH LA English DT Letter ID PARABOLOIDAL NEEDLE CRYSTAL; PERTURBED-SPHERICAL NUCLEUS; PURE SUPERCOOLED LIQUID; TIME DEVELOPMENT; GROWTH; INSTABILITIES; STABILITY AB The nonlinear stage of instability of a planar solid-liquid interface in free solidification, which results in formation of a cell-like pre-dendritic structure, exhibits a new phenomenon absent during the linear growth of the instabilities. It is found that cellular growth is accompanied by generation of solitary waves propagating away from cell tip regions along the interface with increasing amplitudes, terminating in the valleys between adjacent cells. A fully time dependent numerical code is used to integrate in time the standard thermodiffusion model from stochastic initial conditions. RP PINES, V (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 10 TC 1 Z9 1 U1 0 U2 0 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 JUN PY 1993 VL 130 IS 3-4 BP 682 EP 685 DI 10.1016/0022-0248(93)90557-D PG 4 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA LK453 UT WOS:A1993LK45300038 ER PT J AU FOLK, CL REMINGTON, RW JOHNSTON, JC AF FOLK, CL REMINGTON, RW JOHNSTON, JC TI CONTINGENT ATTENTIONAL CAPTURE - A REPLY TO YANTIS (1993) SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Note ID ABRUPT VISUAL ONSETS; SELECTIVE ATTENTION; VOLUNTARY; ALLOCATION; MECHANISMS; PRIORITY; OFFSETS AB Folk, Remington, and Johnston (1992) recently proposed that involuntary shifts of spatial attention, even those elicited by abrupt visual onsets, are contingent on variable internal control settings. Yantis (1993) argues that the results of Jonides and Yantis (1988) significantly challenge this hypothesis and that the paradigm of Folk et al. (1992) is inappropriate for investigating stimulus-driven attentional capture. Yantis's concerns are addressed, and it is concluded that the contingent involuntary orienting hypothesis in fact provides a unified and parsimonious account of the data on attentional capture. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP FOLK, CL (reprint author), VILLANOVA UNIV,DEPT PSYCHOL,VILLANOVA,PA 19085, USA. RI Martin Arevalo, Elisa/L-4472-2014 OI Martin Arevalo, Elisa/0000-0002-4546-6440 NR 21 TC 104 Z9 105 U1 0 U2 2 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 SN 0096-1523 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD JUN PY 1993 VL 19 IS 3 BP 682 EP 685 DI 10.1037/0096-1523.19.3.682 PG 4 WC Psychology; Psychology, Experimental SC Psychology GA LH235 UT WOS:A1993LH23500015 ER PT J AU KIM, J ANTONIA, RA AF KIM, J ANTONIA, RA TI ISOTROPY OF THE SMALL SCALES OF TURBULENCE AT LOW-REYNOLDS-NUMBER SO JOURNAL OF FLUID MECHANICS LA English DT Article ID LOCAL ISOTROPY; BOUNDARY-LAYER; CHANNEL FLOW; SHEAR FLOWS; SPECTRA; WAKE; FLUCTUATIONS; FIELDS AB Spectral local isotropy tests are applied to direct numerical simulation data, mainly at the centreline of a fully developed turbulent channel flow. Despite the small Reynolds number of the simulation, the high-wavenumber behaviour of velocity and vorticity spectra is consistent with local isotropy. This consistency is verified by the relationship between streamwise wavenumber spectra and spanwise wavenumber spectra. The high-wavenumber behaviour of the pressure spectrum is also consistent with local isotropy and compares favourably with the calculation of Batchelor (1951), which assumes isotropy and joint normality of the velocity field at two points in space. The latter assumption is validated by the shape but not the magnitude of the quadruple correlation of the streamwise velocity fluctuation at small separations. There is only partial support for local spectral isotropy away from the centreline as the magnitude of the mean strain rate increases. C1 UNIV NEWCASTLE, DEPT MECH ENGN, NEWCASTLE, NSW 2308, AUSTRALIA. RP NASA, AMES RES CTR, CTR TURBULENCE RES, MOFFETT FIELD, CA 94035 USA. OI Kim, John/0000-0002-6369-9264 NR 42 TC 58 Z9 58 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 EI 1469-7645 J9 J FLUID MECH JI J. Fluid Mech. PD JUN PY 1993 VL 251 BP 219 EP 238 DI 10.1017/S0022112093003398 PG 20 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LK382 UT WOS:A1993LK38200009 ER PT J AU LEE, SS LELE, SK MOIN, P AF LEE, SS LELE, SK MOIN, P TI DIRECT NUMERICAL-SIMULATION OF ISOTROPIC TURBULENCE INTERACTING WITH A WEAK SHOCK-WAVE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID BOUNDARY-LAYER INTERACTION; COMPRESSION-RAMP FLOWS AB Interaction of isotropic quasi-incompressible turbulence with a weak shock wave was studied by direct numerical simulations. The effects of the fluctuation Mach number M(t) of the upstream turbulence and the shock strength M1(2)-1 on the turbulence statistics were investigated. The ranges investigated were 0.0567 less-than-or-equal-to M(t) less-than-or-equal-to 0.110 and 1.05 less-than-or-equal-to M1 less-than-or-equal-to 1.20. A linear analysis of the interaction of isotropic turbulence with a normal shock wave was adopted for comparisons with the simulations. Both numerical simulations and the linear analysis of the interaction show that turbulence is enhanced during the interaction with a shock wave. Turbulent kinetic energy and transverse vorticity components are amplified, and turbulent lengthscales are decreased. The predictions of the linear analysis compare favourably with simulation results for flows with M(t)2 < a(M1(2)-1) with a almost-equal-to 0.1, which suggests that the amplification mechanism is primarily linear. Simulations also showed a rapid evolution of turbulent kinetic energy just downstream of the shock, a behaviour not reproduced by the linear analysis. Investigation of the budget of the turbulent kinetic energy transport equation shows that this behaviour can be attributed to the pressure transport term. Shock waves were found to be distorted by the upstream turbulence, but still had a well-defined shock front for M(t)2 < a(M1(2)-1) with a almost-equal-to 0.1). In this regime, the statistics of shock front distortions compare favourably with the linear analysis predictions. For flows with M(t)2 > a(M1(2)-1) with a almost-equal-to 0.1, shock waves no longer had well-defined fronts: shock wave thickness and strength varied widely along the transverse directions. Multiple compression peaks were found along the mean streamlines at locations where the local shock thickness had increased significantly. C1 STANFORD UNIV, DEPT AERONAUT & ASTRONAUT, STANFORD, CA 94305 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP LEE, SS (reprint author), STANFORD UNIV, DEPT MECH ENGN, STANFORD, CA 94305 USA. NR 49 TC 123 Z9 125 U1 0 U2 12 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUN PY 1993 VL 251 BP 533 EP 562 DI 10.1017/S0022112093003519 PG 30 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LK382 UT WOS:A1993LK38200021 ER PT J AU RODI, W MANSOUR, NN MICHELASSI, V AF RODI, W MANSOUR, NN MICHELASSI, V TI ONE-EQUATION NEAR-WALL TURBULENCE MODELING WITH THE AID OF DIRECT SIMULATION DATA SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID CHANNEL FLOW; LAYER AB The length scales appearing in the relations for the eddy viscosity and dissipation rate in one-equation models were evaluated from direct numerical (DNS) simulation data for developed channel and boundary-layer flow at two Reynolds numbers each. To prepare the ground for the evaluation, the distribution of the most relevant mean-flow and turbulence quantities is presented and discussed, also with respect to Reynolds-number influence and to differences between channel and boundary-layer flow. An alternative model is examined in which (v'2)1/2BAR is used as velocity scale instead of k1/2. With this velocity scale, the length scales now appearing in the model follow closely a linear relationship near the wall. The resulting length-scale relations together with a DNS based relation between v'2/kBAR and y* = k1/2y/v form a new one-equation model for use in near-wall regions. The new model was tested as near wall component of a two-layer model by application to developed-channel, boundary-layer and backward-facing-step flows. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV FLORENCE, I-50121 FLORENCE, ITALY. RP UNIV KARLSRUHE, W-7500 KARLSRUHE, GERMANY. NR 19 TC 48 Z9 48 U1 0 U2 1 PU ASME PI NEW YORK PA TWO PARK AVE, NEW YORK, NY 10016-5990 USA SN 0098-2202 EI 1528-901X J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD JUN PY 1993 VL 115 IS 2 BP 196 EP 205 DI 10.1115/1.2910124 PG 10 WC Engineering, Mechanical SC Engineering GA LK088 UT WOS:A1993LK08800005 ER PT J AU ELLENDER, RD SHARP, SL COMAR, PG TETTLETON, RP AF ELLENDER, RD SHARP, SL COMAR, PG TETTLETON, RP TI RAPID METHODS TO EVALUATE THE BACTERIOLOGICAL QUALITY OF FROZEN CRABMEAT SO JOURNAL OF FOOD PROTECTION LA English DT Note ID AEROBIC PLATE-COUNT; PETRIFILM; REDIGEL AB The standard methods plate count (SMPC) of frozen crabmeat samples was compared with counts of two alternative aerobic plate count methods (Redigel, Petrifilm). The differences in counts were compared after incubation at two temperatures (35-degrees-C and room temperature; RT) and three intervals of time (24, 48, and 72 h). No statistical differences were found when the time of analysis or the method of analysis was compared. However, differences were observed within SMPC values and within Petrifilm plate count values when RT was compared to 35-degrees-C. Redigel plate counts at RT and 35-degrees-C were not significantly different. The results suggest that seafood plants could use the Redigel media, incubate samples at room temperature for 48 h, and furnish data comparable to SMPC. C1 NATL MARINE FISHERIES SERV,NATL SEAFOOD INSPECT LAB,PASCAGOULA,MS 39568. RP ELLENDER, RD (reprint author), UNIV SO MISSISSIPPI,DEPT BIOL SCI,BOX 5153,HATTIESBURG,MS 39406, USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU INT ASSOC MILK FOOD ENVIRONMENTAL SANITARIANS, INC PI DES MOINES PA 6200 AURORA AVE SUITE 200W, DES MOINES, IA 50322-2838 SN 0362-028X J9 J FOOD PROTECT JI J. Food Prot. PD JUN PY 1993 VL 56 IS 6 BP 545 EP 547 PG 3 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA LJ893 UT WOS:A1993LJ89300018 ER PT J AU DELCOURT, DC SAUVAUD, JA MOORE, TE AF DELCOURT, DC SAUVAUD, JA MOORE, TE TI POLAR WIND ION DYNAMICS IN THE MAGNETOTAIL SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CHARGED-PARTICLE MOTION; PLASMA SHEET; GEOMAGNETIC TAIL; MAGNETIC NULL; MAGNETOSPHERE; ACCELERATION; FIELD; ORBITS; MODEL; IONOSPHERE AB The circulation of polar wind ions from the high-latitude ionosphere to the plasma sheet is examined by means of three-dimensional particle codes. The simulations reveal the possible creation of high-altitude mirror points for particles traveling in the equatorial magnetotail. It is shown that this feature follows from large centrifugal decelerations in the course of the fast ExB transport, and not from nonadiabatic motion in the local field reversal. Such decelerations yield the confinement (here termed ''centrifugal trapping'') of populations with relatively small parallel speed near the tail midplane. It is also demonstrated that the net polar wind plasma supply to the plasma sheet critically depends upon the dynamics of ions which originate from the highest latitudes of the dayside ionosphere. During quiet times, these particles gain access to the distant tail where they experience durable nonadiabatic trapping. Accordingly, it is found that the polar wind forms a prominent source of plasma for the central nightside sector, yielding appreciable density levels (of the order of several tenths of ions cm-3) in the characteristic plasma sheet energy range (from hundreds of electron volts up to a few kiloelectron volts). A lesser contribution is obtained during active times, as the low-energy ions are confined to low L shells where they essentially travel in an adiabatic manner. Thus, in addition to emphasizing the role of ionospheric ion dynamics inside the neutral sheet, the trajectory simulations suggest that the polar wind efficiency in feeding the plasma sheet depends upon the time evolution of the particles, rather than from an increasing plasma supply from low to high Kp. C1 CTR ETUD SPATIALE RAYONNEMENTS,F-31029 TOULOUSE,FRANCE. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP DELCOURT, DC (reprint author), CTR NATL ETUD TELECOMMUN,CTR RECH PHYS ENVIRONM,F-94107 ST MAUR FOSSES,FRANCE. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 30 TC 43 Z9 43 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9155 EP 9169 DI 10.1029/93JA00301 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800001 ER PT J AU OMURA, Y GREEN, JL AF OMURA, Y GREEN, JL TI PLASMA-WAVE SIGNATURES IN THE MAGNETOTAIL RECONNECTION REGION - MHD SIMULATION AND RAY-TRACING SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC RECONNECTION AB We present the results of an innovative and powerful new technique to be used in the interpretation of Geotail plasma wave data when the spacecraft is in the deep magnetotail during potential reconnection events. To provide the best possible magnetotail structure of magnetic fields and plasma densities, an MHD simulation is performed. At precisely the moment of reconnection, during the simulation, the magnetotail structure is used in the ray tracing calculations of various plasma waves expected to be generated in the X point region, Several wave modes are studied in detailed (L mode ion cyclotron, R mode ion cyclotron, lower hybrid waves, whistler mode waves, and L-0 and R-X mode waves). Ray tracing calculations are performed in these modes as generated from a point source at all wave normal angles in the reconnection region. When we assume each ray is generated at the same intensity, a ray density distribution is derived for the entire spatial reconnection region for several frequencies that each of the plasma wave modes can support in the MHD magnetotail model. As a hypothetical spacecraft transverses the tail reconnection structure along a typical trajectory, a pseudofrequency time spectrogram can then be constructed. It is clear that each of these wave modes has a distinctive pattern of propagation, along the magnetic field, transverse to the magnetic field, or trapped within the resulting plasmoid or reconnection region and should be easily distinguished in Geotail measurements. C1 KYOTO UNIV,CTR RADIO ATMOSPHER SCI,UJI,KYOTO 611,JAPAN. RP OMURA, Y (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 630,GREENBELT,MD 20771, USA. RI Omura, Yoshiharu/P-8565-2014 OI Omura, Yoshiharu/0000-0002-6683-3940 NR 19 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9189 EP 9199 DI 10.1029/92JA02901 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800004 ER PT J AU DEGONZALEZ, ALC GONZALEZ, WD DUTRA, SLG TSURUTANI, BT AF DEGONZALEZ, ALC GONZALEZ, WD DUTRA, SLG TSURUTANI, BT TI PERIODIC VARIATION IN THE GEOMAGNETIC-ACTIVITY - A STUDY BASED ON THE AP INDEX SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; SOLAR-CYCLE; SEMIANNUAL VARIATION; SPECTRAL-ANALYSIS; SUNSPOT CYCLE; WIND; POLARITY; FLARES; EVENTS AB The monthly and daily samples of the Ap geomagnetic index for 51 years, 1932-1982, were investigated by means of the power spectrum technique, In general, the results confirm previous findings about possible periodicities in the geomagnetic activity. However, in our opinion the following aspects are either new or they are being interpreted somewhat differently than other authors have done. The period around 4 years in the monthly Ap power spectrum is associated to the double peak structure observed in the geomagnetic activity variation [Gonzalez et al., 1990]. Several of the peaks shown by the daily Ap spectrum are interpreted as harmonics of the 6-month period and other peaks as caused by the solar rotation periodicity, in such a way that the two series of Fourier sequences are consider to be juxtaposed. A strong solar cycle modulation is observed in these series, particularly iii that related to the solar rotation period, which almost disappears for the solar maximum phase. The study of the seasonal variation was complemented by a superposed epoch analysis. The profiles resulting from this analysis seem to show a multiple origin of the 6-month periodicity, so that it does not seem realistic to search for a unique cause for this well-known seasonal variation. This conclusion is also supported by the histograms of the occurrence of storms above a given intensity level, taken over short duration intervals (i.e., 8 days). According to these histograms, for large data samples the dates with largest number of storms are spread out around those predicted by the different theoretical models, while for short intervals the semiannual periodicity may sometimes not even be present. Therefore these known mechanisms would combine to give a resulting modulation of the geomagnetic response to the randomly generated source of storms. It was also found that an additional seasonal peak seems to exist in July, with an amplitude comparable to those of the equinoctial peaks, for the range of the most intense storms (Ap greater-than-or-equal-to 150 nT). A weak periodicity around 158 days, well correlated to that of about 155 days observed in the solar activity, has also been detected for some years during solar cycle 21. C1 JET PROP LAB,PASADENA,CA 91109. RP DEGONZALEZ, ALC (reprint author), INST NACL PESQUISAS ESPACIAIS,CP 515,BR-12201-970 SAN JOSE CAM,SP,BRAZIL. NR 74 TC 58 Z9 58 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9215 EP 9231 DI 10.1029/92JA02200 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800006 ER PT J AU KOZYRA, JU CHANDLER, MO HAMILTON, DC PETERSON, WK KLUMPAR, DM SLATER, DW BUONSANTO, MJ CARLSON, HC AF KOZYRA, JU CHANDLER, MO HAMILTON, DC PETERSON, WK KLUMPAR, DM SLATER, DW BUONSANTO, MJ CARLSON, HC TI THE ROLE OF RING CURRENT NOSE EVENTS IN PRODUCING STABLE AURORAL RED ARC INTENSIFICATIONS DURING THE MAIN PHASE - OBSERVATIONS DURING THE SEPTEMBER 19-24, 1984, EQUINOX TRANSITION STUDY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERNATIONAL REFERENCE IONOSPHERE; ELECTRON-TEMPERATURE ENHANCEMENT; SOLAR-CYCLE; MILLSTONE HILL; MID-LATITUDES; STORM; PLASMASPHERE; PARTICLES; DENSITY; MODEL AB An examination of stable auroral red (SAR) arc emissions over the last solar cycle (Slater and Kleckner, 1989) indicates that the strongest emissions, during the lifetime of a particular SAR arc, often occur in association with the main phase of the magnetic storm. Previous observations of thermal and energetic particle populations at high and low altitudes on SAR arc field lines by Kozyra et al. (1987a) indicate that the energy source for these emissions is the O+ in the ring current. The O+ content of the ring current increases with increasing magnetic activity reaching its maximum percentage contribution near minimum Dst for a particular storm. This variation in the O+ content of the ring current is inconsistent with an early main phase enhancement of SAR arc emissions. To investigate the source of main phase enhancements in SAR arc emissions, a study of the September 19-24, 1984, magnetic storm period during which SAR arc emissions were observed by the ground-based mobile automatic scanning photometer network in both the main and recovery phases is presented. The emissions associated with the main phase (approximately 400 R) were an order of magnitude greater than those associated with the recovery phase (tens of R). Energetic particle measurements from the DE 1 and AMPTE spacecraft, on field lines that map to the SAR arc position at low altitude, were examined to determine if differences in the energy sources during these time periods were evident. In agreement with previous work, ring current O+ supplied the bulk of the electron heating during storm recovery phase as a result of Coulomb collisions of O+ with the plasmaspheric electrons; contributions by ring current H+ were negligible. A new result of the present work is that an enhancement of the 15-25 keV H+ component of the ring current during the main phase of the September 19 magnetic storm was responsible for an approximately one order of magnitude increase in the electron heating rate and SAR arc emissions during the main phase compared to the recovery phase. The increase in the H+ flux occurred in association with a ring current ''nose event'', a front of ions injected into the inner magnetosphere in response to a discontinuous change in the cross-tail electric field. The association between nose events and intensifications of SAR arc emissions in the main phase has not previously been explored but is a natural consequence of the injection of significant fluxes of relatively low-energy ring current ions earthward of the plasmapause during early storm time ring current formation. C1 MIT, HAYSTACK OBSERV, WESTFORD, MA 01886 USA. PHILIPS LAB, BEDFORD, MA 01731 USA. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. UNIV MARYLAND, DEPT PHYS & ASTRON, COLL PK, MD 20742 USA. LOCKHEED PALO ALTO RES LABS, DEPT 91-20, PALO ALTO, CA 94304 USA. PACIFIC NW LAB, DEPT GEOSCI, RICHLAND, WA 99352 USA. RP KOZYRA, JU (reprint author), UNIV MICHIGAN, DEPT ATMOSPHER OCEAN & SPACE SCI, SPACE PHYS RES LAB, ANN ARBOR, MI 48109 USA. RI Peterson, WK/A-8706-2009 OI Peterson, WK/0000-0002-1513-6096 NR 50 TC 19 Z9 19 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9267 EP 9283 DI 10.1029/92JA02554 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800010 ER PT J AU CROOKER, NU SISCOE, GL SHODHAN, S WEBB, DF GOSLING, JT SMITH, EJ AF CROOKER, NU SISCOE, GL SHODHAN, S WEBB, DF GOSLING, JT SMITH, EJ TI MULTIPLE HELIOSPHERIC CURRENT SHEETS AND CORONAL STREAMER BELT DYNAMICS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLANETARY SECTOR BOUNDARIES; SOLAR-WIND; MAGNETIC CLOUDS; MASS EJECTIONS; 1-AU AB The occurrence of multiple directional discontinuities in the coronal streamer belt at sector boundary crossings in the heliosphere, often ascribed to waves or kinks in the heliospheric current sheet, may alternatively be attributed to a network of extended current sheets from multiple helmet streamers with a hierarchy of sizes at the base of the corona. Frequent transient outflows from these helmets can account for a variety of signatures observed at sector boundaries, including ordered field rotations, planar magnetic structure, and sandwichlike plasma structure. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. BOSTON UNIV,CTR SPACE PHYS,BOSTON,MA 02215. JET PROP LAB,PASADENA,CA 91109. PHILLIPS LAB,GPSG,BEDFORD,MA 01731. RP CROOKER, NU (reprint author), UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,LOS ANGELES,CA 90024, USA. NR 49 TC 127 Z9 129 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9371 EP 9381 DI 10.1029/93JA00636 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800021 ER PT J AU NEUGEBAUER, M CLAY, DR GOSLING, JT AF NEUGEBAUER, M CLAY, DR GOSLING, JT TI THE ORIGINS OF PLANAR MAGNETIC-STRUCTURES IN THE SOLAR-WIND SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLANETARY SECTOR BOUNDARIES; EVENTS AB The term ''planar magnetic structure'' (PMS) refers to distinctive features in the solar wind characterized by a series of abrupt changes in the direction of the interplanetary field, with the field remaining nearly parallel to a single plane. Previous suggestions concerning the origin of PMS are (1) closed magnetic field loops arising from newly emerging, nearly parallel magnetic structures in the photosphere, (2) compression and draping of the field around a high-speed coronal mass ejection (CME), and (3) extended current sheets and/or loops from multiple helmet streamers in the corona. Four years of ISEE 3 data have been examined to establish a larger data base of PMS events and to allow a search for common features that may reveal the causes of these structures. A total of 33 PMS events were found and analyzed. The loop theory of PMS origins was tested by searching for a correlation between the PMSs and the electron or proton counterstreaming characteristic of closed loops or CMEs. It was found that the PMSs tended to precede rather than coincide with the CMEs. Fourteen of the PMS events (42%) were in the sheath between an interplanetary shock and a CME. Other PMS events were found to be related to crossings of the heliospheric current sheet (HCS). Sorting the events according to their association with either HCS or compression/draping ahead of fast streams (of which postshock sheaths are a subset) yields 19 events (58%) associated with compression/draping but not with HCS, 8 events (24%) associated with both compression/draping and HCS, 5 events (15%) associated with HCS but not with compression/draping, and 1 event (3%) associated with neither compression/draping nor the HCS. The conclusion is that planar magnetic structures are not closed loops of plasma from coronal mass ejections or helmet streamers. Instead, a process is postulated in which coronal mass ejections lead to the amplification and alignment of preexisting discontinuities in the ambient wind compressed by the CMEs. A possible cause of the alignment of discontinuities in the vicinity of the heliospheric current sheet is compression by lateral expansion of CMEs in the lower corona. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP NEUGEBAUER, M (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 19 TC 36 Z9 36 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9383 EP 9389 DI 10.1029/93JA00216 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800022 ER PT J AU GAZIS, PR AF GAZIS, PR TI PIONEER VENUS AND IMP-8 OBSERVATIONS OF THE LATITUDE DEPENDENCE OF THE SOLAR-WIND SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HELIOSPHERIC CURRENT SHEET; LONGITUDE STRUCTURE; MULTI-SPACECRAFT; SECTOR STRUCTURE; VELOCITY; SPEED; MINIMUM AB Solar wind speeds and magnetic field data from the Pioneer Venus orbiter (0.7 AU) and IMP 8 spacecraft (1 AU) are compared to infer the latitudinal structure of the solar wind in the inner heliosphere between 1984 and 1987. It is found that solar wind streams and the interplanetary magnetic field (IMF) exhibited an unusual configuration during the last solar minimum (1986-1987). This configuration only appeared during a limited period around the time of solar minimum, and was similar to the configuration that appeared during the previous solar minimum in 1975. Prior to solar minimum, the solar wind speed did not appear to vary with heliographic latitude, and the same high-speed streams appeared at both spacecraft even when they were widely separated. The IMF had a two-sector structure at all latitudes. During solar minimum, this situation changed, and high-speed streams were excluded from low (<3-degrees) latitudes, while the vicinity of the solar equator was characterized by slow solar wind and irregular variations in speed. The sector structure of the IMF also changed during solar minimum, and a single polarity predominated at latitudes greater than 4-degrees. The onset of these changes appears to be related to a decrease in the inclination of the coronal neutral line; from approximately 40-degrees at the end of 1984 to approximately 10-degrees in the beginning of 1986. This is consistent with suggestions by previous observers that the coronal neutral line is associated with a sheet of low-speed solar wind without high-speed streams. RP GAZIS, PR (reprint author), NASA, AMES RES CTR, SAN JOSE STATE UNIV FDN, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 22 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1993 VL 98 IS A6 BP 9391 EP 9400 DI 10.1029/92JA03000 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LG058 UT WOS:A1993LG05800023 ER PT J AU LEE, S SHIN, YG AF LEE, S SHIN, YG TI ASSEMBLY COPLANNER - COOPERATIVE ASSEMBLY PLANNER BASED ON SUBASSEMBLY EXTRACTION SO JOURNAL OF INTELLIGENT MANUFACTURING LA English DT Article DE ASSEMBLY PLANNING; SUBASSEMBLY; LIAISON GRAPH; GEOMETRIC REASONING; ASSEMBLY COST; STABILITY; PARTIAL-ORDER GRAPH AB The distribution of assembly workstations enables assembly operations to be done in parallel, while the multiple routing of parts in flexible assembly systems allows the opportunistic scheduling of assembly operations. This paper presents an assembly planning system, called the Assembly Coplanner. which automatically constructs an assembly partial order and generates a set of assembly instructions from a liaison graph representation of an assembly based on the extraction of preferred subassemblies. Assembly planning in Coplanner is carried out by the co-operation of multiple planning agents, such as the geometric reasoner, the physical reasoner, the resource manager and the plan coordinator, under the constraints of finding a cost-effective assembly plan in a flexible assembly system. The Coplanner identifies spatial parallelism in assembly as a means of constructing temporal parallelism among assembly operations. This is achieved in the following way: (1) the selection of a set of tentative subassemblies by decomposing a liaison graph into a set of subgraphs based on feasibility and difficulty of disassembly; (2) the evaluation of each of the tentative subassemblies in terms of assembly cost represented by subassembly selection indices; and (3) the construction of a hierarchical partial order graph (HPOG) as an assembly plan. A case study applying the Coplanner to a mechanical assembly is illustrated in this paper. C1 JET PROP LAB,PASADENA,CA 91109. UNIV SO CALIF,DEPT ELECT ENGN SYST,LOS ANGELES,CA 90089. NR 15 TC 10 Z9 10 U1 1 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0956-5515 J9 J INTELL MANUF JI J. Intell. Manuf. PD JUN PY 1993 VL 4 IS 3 BP 183 EP 198 DI 10.1007/BF00123963 PG 16 WC Computer Science, Artificial Intelligence; Engineering, Manufacturing SC Computer Science; Engineering GA LJ600 UT WOS:A1993LJ60000001 ER PT J AU DEGUIRE, MR PHILIPP, WB AF DEGUIRE, MR PHILIPP, WB TI GUANIDINE OXALATE - A NEW REAGENT FOR COPRECIPITATION IN THE SYNTHESIS OF MULTICOMPONENT CERAMICS SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article DE COPRECIPITATION; CERAMICS; GUANIDINE OXALATE; POWDER SYNTHESIS; THERMAL ANALYSIS AB Guanidine oxalate, [H2NC(=NH)NH2]2H2C2O4, has been synthesized and isolated. This paper reports its first use as a precipitating agent in the production of coprecipitated multicomponent oxide powder precursors. The compound can be synthesized using inexpensive starting materials. We have demonstrated its use in the synthesis of several mixed-oxide systems, including magnetic oxides, catalysts, and superconducting cuprates. Highly quantitative precipitations were achieved in each case with no pH adjustment. C1 NASA,LEWIS RES CTR,DIV MAT,CERAM BRANCH,CLEVELAND,OH 44135. RP DEGUIRE, MR (reprint author), CASE WESTERN RESERVE UNIV,DEPT MAT SCI & ENGN,CLEVELAND,OH 44106, USA. NR 13 TC 2 Z9 2 U1 1 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0959-9428 J9 J MATER CHEM JI J. Mater. Chem. PD JUN PY 1993 VL 3 IS 6 BP 571 EP 574 DI 10.1039/jm9930300571 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA LG536 UT WOS:A1993LG53600003 ER PT J AU SEIFERT, CM SHAFTO, MG AF SEIFERT, CM SHAFTO, MG TI UNIFIED THEORIES OF COGNITION - NEWELL,A SO JOURNAL OF MATHEMATICAL PSYCHOLOGY LA English DT Book Review ID ARCHITECTURE; INTELLIGENCE; SOAR C1 NASA,AMES RES CTR,FLIGHT HUMAN FACTORS BRANCH,MOFFETT FIELD,CA 94035. RP SEIFERT, CM (reprint author), UNIV MICHIGAN,ANN ARBOR,MI 48109, USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2496 J9 J MATH PSYCHOL JI J. Math. Psychol. PD JUN PY 1993 VL 37 IS 2 BP 311 EP 323 DI 10.1006/jmps.1993.1019 PG 13 WC Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods; Psychology, Mathematical SC Mathematics; Mathematical Methods In Social Sciences; Psychology GA LE961 UT WOS:A1993LE96100009 ER PT J AU FRUM, CI PICKETT, HM AF FRUM, CI PICKETT, HM TI HIGH-RESOLUTION INFRARED FOURIER-TRANSFORM EMISSION-SPECTROSCOPY OF METAL-HYDRIDES - X(2)SIGMA+STATE OF CAH SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID CALCIUM HYDRIDE; SPECTRUM; (H2O)-O-16; STATES RP FRUM, CI (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 23 TC 11 Z9 11 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUN PY 1993 VL 159 IS 2 BP 329 EP 336 DI 10.1006/jmsp.1993.1130 PG 8 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA LE316 UT WOS:A1993LE31600003 ER PT J AU CARTEN, KP LOVEJOY, RW CHACKERIAN, C AF CARTEN, KP LOVEJOY, RW CHACKERIAN, C TI ABSOLUTE LINE-INTENSITIES FOR THE NU(2) BAND OF (CH3D)-C-12 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID CH3D C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP CARTEN, KP (reprint author), LEHIGH UNIV,DEPT CHEM,BETHLEHEM,PA 18015, USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUN PY 1993 VL 159 IS 2 BP 337 EP 339 DI 10.1006/jmsp.1993.1131 PG 3 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA LE316 UT WOS:A1993LE31600004 ER PT J AU WEBER, M BLASS, WE REUTER, DC JENNINGS, DE HILLMAN, JJ AF WEBER, M BLASS, WE REUTER, DC JENNINGS, DE HILLMAN, JJ TI THE GROUND-STATE OF (CCH6)-C-13-C-12 (ETHANE) DERIVED FROM NU-12 AT 12.2 MU-M SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID INFRARED OBSERVATIONS; FOURIER-TRANSFORM; JUPITER; SPECTRA; SATURN C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. UNIV TENNESSEE,CTR COMP,KNOXVILLE,TN 37996. RP WEBER, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI Blass, William/A-2792-2008; Weber, Mark/F-1409-2011; Jennings, Donald/D-7978-2012 OI Weber, Mark/0000-0001-8217-5450; NR 24 TC 5 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUN PY 1993 VL 159 IS 2 BP 388 EP 394 DI 10.1006/jmsp.1993.1136 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA LE316 UT WOS:A1993LE31600009 ER PT J AU AHN, MK STRINGFELLOW, TC FASANO, M BOWLES, KJ MEADOR, MA AF AHN, MK STRINGFELLOW, TC FASANO, M BOWLES, KJ MEADOR, MA TI ELECTRON-PARAMAGNETIC-RESONANCE SPECTROSCOPIC STUDIES OF THERMALLY GENERATED FREE-RADICALS IN PMR-15 POLYIMIDE RESINS SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE POLYIMIDE; EPR; FREE RADICALS ID COMPOSITES AB PMR-15 is a high-performance thermoset polyimide resin that is used in many high-temperature applications. Postcured PMR-15 produces room-temperature electron paramagnetic resonance (EPR) spectra from stable free-radical species that are formed during the postcuring stages. The variable-temperature EPR spectral intensities show a minimum at T(min). in the range -60 to -40-degrees=C, and a maximum at T(max) in the range 80-120-degrees-C. The EPR intensities follow the inverse temperature dependence of Curie's law below T(min) and are due to a stable free radical. The intensities then increase with increasing temperature between T(min) and T(max). The free radical with such temperature dependence is not present below T(min) and is undetectable by EPR at temperatures above T(max). These free radicals are generated during the postcuring process at elevated temperature above 310-degrees-C. The thermo-oxidative degradation involves free radicals generated during the postcuring process in the presence of oxygen gas. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP AHN, MK (reprint author), INDIANA STATE UNIV,DEPT CHEM,TERRE HAUTE,IN 47809, USA. NR 25 TC 12 Z9 12 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JUN PY 1993 VL 31 IS 7 BP 831 EP 841 DI 10.1002/polb.1993.090310711 PG 11 WC Polymer Science SC Polymer Science GA LD053 UT WOS:A1993LD05300011 ER PT J AU MYNENI, RB ASRAR, G AF MYNENI, RB ASRAR, G TI RADIATIVE-TRANSFER IN 3-DIMENSIONAL ATMOSPHERE VEGETATION MEDIA SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SCATTERING; CANOPIES AB The problem of radiation transfer in three-dimensional atmosphere-vegetation media is formulated in this paper. The atmosphere is treated as a horizontally homogeneous medium but with spatially varying anisotropic lower boundary. The boundary condition is defined in terms of vegetation canopy bidirectional reflectance factors to be evaluated from a numerical solution of the three-dimensional canopy radiative transfer equation. Numerical results obtained with the discrete ordinates method are in good agreement with the Monte Carlo results of Pearce and field soybean reflectance data of Ranson et al. C1 NASA HEADQUARTERS,WASHINGTON,DC 20546. RP MYNENI, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Myneni, Ranga/F-5129-2012 NR 19 TC 49 Z9 49 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1993 VL 49 IS 6 BP 585 EP 598 DI 10.1016/0022-4073(93)90003-Z PG 14 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LG398 UT WOS:A1993LG39800002 ER PT J AU PRABHAKARA, C YOO, JM KRATZ, DP DALU, G AF PRABHAKARA, C YOO, JM KRATZ, DP DALU, G TI BOUNDARY-LAYER STRATUS CLOUDS - INFERRED FROM SATELLITE INFRARED SPECTRAL MEASUREMENTS OVER OCEANS SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB A method to remotely sense marine stratus clouds, that are underneath the boundary layer inversion produced by strong subsidence, is developed with the help of the measurements made by the Infrared Interferometer Spectrometer (IRIS) on board the Nimbus 4 satellite. These measurements, which had a spectral resolution of 2.8 cm-1 and a field view of approximately 100 km in the region 870-980 cm-1, allow one to compare the weak absorption due to water vapor lines with that of the weak nu3-nu1 band of CO2. From such a comparison it is possible to sense the presence of these boundary layer stratus clouds. Maps of these clouds over subsidence regions of the tropical and subtropical oceans deduced from IRIS data show the usefulness of the technique to climatological studies. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. CNR,AREA RIC CAGLIARI,CAGLIARI,ITALY. APPL RES CORP,LANDOVER,MD 20785. RP PRABHAKARA, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1993 VL 49 IS 6 BP 599 EP 607 DI 10.1016/0022-4073(93)90004-2 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LG398 UT WOS:A1993LG39800003 ER PT J AU BHATIA, AK KASTNER, SO AF BHATIA, AK KASTNER, SO TI ATOMIC DATA FOR A 5-CONFIGURUATION MODEL OF FE XIV SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID CROSS-SECTIONS; NI-XVI; LINES; IONS; TRANSITIONS; EXCITATION; SPECTRUM; SUN AB Collision strengths calculated in the distorted wave approximation am presented for electron excitation of Fe XIV at incident energies of 10, 20 and 30 Rydbergs. Configurations 3s(2)3p, 3s3p2, 3s(2)3d, 3p3 and 3s3p3d are included, comprising 40 levels, and wave function mixing coefficients are tabulated. Radiative transition rates are given for the same model using the Superstructure program. C1 MATH SCI CONSULTANTS INC,GREENBELT,MD 20770. RP BHATIA, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 16 TC 24 Z9 24 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1993 VL 49 IS 6 BP 609 EP 625 DI 10.1016/0022-4073(93)90005-3 PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LG398 UT WOS:A1993LG39800004 ER PT J AU HARTMANN, JM PERRIN, MY MA, Q TIPPING, RH AF HARTMANN, JM PERRIN, MY MA, Q TIPPING, RH TI THE INFRARED CONTINUUM OF PURE WATER-VAPOR - CALCULATIONS AND HIGH-TEMPERATURE MEASUREMENTS SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID INDUCED POPULATION TRANSFER; MILLIMETER-WAVE-PROPAGATION; AUTO-CORRELATION FUNCTION; 720-NM WAVELENGTH REGION; LINE-SHAPE; ABSORPTION SPECTRA; FINITE DURATION; STATISTICAL-THEORY; ROTATIONAL BANDS; FAR WINGS AB We present experimental and theoretical studies of medium infrared absorption by pure water vapor. Measurements have been made in the 1900-2600 cm-1 and 3900-4600 cm-1 regions, for temperatures and pressures in the 500-900 K and 0-70 atm ranges, respectively. They are consistent with available data and enable the determination of continuum absorption parameters. It is shown that calculations with line shapes derived from the impact approximation are very inaccurate. Models accounting for the finite durations of collisions and line-mixing through wave-number dependent effective broadening parameters are introduced. The latter have been determined using two different approaches, which are (i) empirical determinations from fits of experimental data and (ii) direct predictions from first principles using a statistical approach. Effective broadening parameters obtained using these two different approaches are in satisfactory agreement for both the temperature and wavenumber dependencies. These data are tested by calculations of continua in various spectral regions and the agreement with measured values is satisfactory. The remaining discrepancies probably result from the influence of the internal structures of the absorption bands considered and thus from the influence of line-mixing. Nevertheless, accurate predictions are obtained in wide temperature and spectral ranges when the total absorption at elevated density is considered. This agreement, which is due to the relatively weak continuum absorption and large contributions of nearby lines, makes the present models suitable for most practical applications involving elevated densities. C1 UNIV ALABAMA,DEPT PHYS & ASTRON,TUSCALOOSA,AL 35487. CNRS,UPR288,E M2 C LAB,F-92295 CHATENAY MALABRY,FRANCE. COLUMBIA UNIV,CTR STUDY GLOBAL HABITABIL,NEW YORK,NY 10025. ECOLE CENT PARIS,F-92295 CHATENAY MALABRY,FRANCE. GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025. OI Perrin, Marie Yvonne/0000-0002-9205-5273 NR 88 TC 34 Z9 36 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1993 VL 49 IS 6 BP 675 EP 691 DI 10.1016/0022-4073(93)90010-F PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LG398 UT WOS:A1993LG39800009 ER PT J AU HEYMAN, JS FROGGATT, M AF HEYMAN, JS FROGGATT, M TI ULTRASONIC DYNAMIC VECTOR STRESS SENSOR SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Note RP HEYMAN, JS (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1993 VL 93 IS 6 BP 3522 EP 3522 DI 10.1121/1.405686 PG 1 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA LF769 UT WOS:A1993LF76900056 ER PT J AU MADRAS, EI KLINE, RA AF MADRAS, EI KLINE, RA TI X-RAY AND ACOUSTIC MEASUREMENTS YIELD STIFFNESSES SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Note C1 UNIV OKLAHOMA,NORMAN,OK 73019. RP MADRAS, EI (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1993 VL 93 IS 6 BP 3522 EP 3523 DI 10.1121/1.405687 PG 2 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA LF769 UT WOS:A1993LF76900057 ER PT J AU HABERLE, RM HOUBEN, HC HERTENSTEIN, R HERDTLE, T AF HABERLE, RM HOUBEN, HC HERTENSTEIN, R HERDTLE, T TI A BOUNDARY-LAYER MODEL FOR MARS - COMPARISON WITH VIKING LANDER AND ENTRY DATA SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GLOBAL DUST STORMS; MARTIAN ATMOSPHERE; GENERAL-CIRCULATION; SIMULATIONS; TOPOGRAPHY; EARTH AB A one-dimensional boundary-layer model for Mars is described, and its results are compared with Viking data. The model equations are similar to Earth boundary-layer models in that they include contributions from Coriolis, pressure gradient, and frictional forces for momentum; and radiation, sensible heat flux convergence, and advection for heat. Turbulent fluxes are computed from the level-2 second-order closure theory of Mellor and Yamada with similarity relations employed for boundary conditions. The pressure gradient force can be specified or computed from a simple slope model. Radiative heating is due to the absorption of solar and infrared radiation by CO2 ps and suspended dust particles. Ground temperatures are computed by solving a surface heat budget using an accurate treatment of conduction into the Martian soil. The data used for comparison were obtained by the Viking 1 and 2 landers for early northern summer. At each site, these data include a single profile of wind and temperature between 1.5 and 4 km and their diurnal variations at 1.6 m above the surface. Model-predicted temperatures are in good agreement with the data, though they show a greater variation at 1.6 m than is evident in the data. Model-predicted winds compare less favorably in that they can match the surface data or the profiles, but not both simultaneously. In addition, best agreement is obtained using a slope magnitude and/or direction that is different from reported values. However, the model can reproduce the shape, phase, and sense of rotation of the surface wind hodograph at each site. Some features of the simulations include low-level nocturnal jets, which may be common on Mars, and a negative feedback between dust and surface stress. The sensitivity of the model to uncertain parameters such as dust load, optical properties, and surface roughness is discussed. C1 SPACE PHYS RES INST,SUNNYVALE,CA. SAN JOSE STATE UNIV,DEPT METEOROL,SAN JOSE,CA 95192. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP HABERLE, RM (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,55T 245-3,MOFFETT FIELD,CA 94035, USA. NR 45 TC 82 Z9 82 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1993 VL 50 IS 11 BP 1544 EP 1559 DI 10.1175/1520-0469(1993)050<1544:ABLMFM>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LG782 UT WOS:A1993LG78200007 ER PT J AU SHIH, H MANSFELD, F BLUE, G MORAN, C AF SHIH, H MANSFELD, F BLUE, G MORAN, C TI ELECTROCHEMICAL MEASUREMENTS OF THE CORROSION BEHAVIOR OF TYPE 304LSS IN N2H4 CONTAINING CO2 SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID POLARIZATION RESISTANCE; IMPEDANCE MEASUREMENTS; RATES; SYSTEMS AB Electrochemical dc and ac methods were used to evaluate the corrosion behavior of stainless steel 304L in hydrazine (N2H4) with or without additions Of CO2. Tafel slopes and corrosion current densities were obtained from the analysis of polarization curves recorded in the vicinity of the corrosion potential after elimination of the ohmic drop. Electrochemical impedance spectroscopy was used to monitor the continuous changes of the corrosion kinetics with increasing additions of CO2 in N2H4. The results obtained with both techniques show that minute addition (up to 100 PPM) Of CO2 increased the corrosion rate of the stainless steel in N2H4. Further CO2 addition produced no additional changes. C1 JET PROP LAB,PASADENA,CA 91109. RP SHIH, H (reprint author), UNIV SO CALIF,DEPT MAT SCI & ENGN,CORROS & ENVIRONM EFFECTS LAB,LOS ANGELES,CA 90089, USA. NR 29 TC 0 Z9 0 U1 0 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUN PY 1993 VL 140 IS 6 BP 1661 EP 1666 DI 10.1149/1.2221619 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA LG410 UT WOS:A1993LG41000033 ER PT J AU FOSSUM, ER AF FOSSUM, ER TI ACTIVE-PIXEL SENSORS CHALLENGE CCDS SO LASER FOCUS WORLD LA English DT Article ID IMAGE SENSOR RP FOSSUM, ER (reprint author), JET PROP LAB,IMAGING SYST SECT,PASADENA,CA 91109, USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD JUN PY 1993 VL 29 IS 6 BP 83 EP 87 PG 5 WC Optics SC Optics GA MC385 UT WOS:A1993MC38500025 ER PT J AU CONVERTINO, VA AF CONVERTINO, VA TI ENDURANCE EXERCISE TRAINING - CONDITIONS OF ENHANCED HEMODYNAMIC-RESPONSES AND TOLERANCE TO LBNP SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE ORTHOSTATISM; VO(2MAX); BAROREFLEX; BLOOD PRESSURE; HEART RATE; STROKE VOLUME; CARDIAC OUTPUT; BLOOD VOLUME; NOREPINEPHRINE; VASOPRESSIN ID BODY NEGATIVE-PRESSURE; ORTHOSTATIC INTOLERANCE; PHYSICAL-FITNESS; BLOOD-PRESSURE; CARDIOVASCULAR-RESPONSE; BAROREFLEX RESPONSES; AEROBIC CAPACITY; HEAT ACCLIMATION; MEN; ADAPTATIONS AB In cross-sectional comparisons, several investigators have reported highly trained endurance athletes to have a prevalence toward orthostatic hypotension and intolerance compared with average fit individuals. These observations have raised concern that regular exercise designed to increase aerobic capacity may impair regulatory mechanisms of blood pressure control and that perhaps certain populations of individuals with a predisposition for fainting exhibit an inability to elevate heart rate, vasoactive hormones, and peripheral resistance during an orthostatic challenge. In longitudinal experiments, when exercise training was performed by subjects who increased their aerobic capacity by 20% but maintained VO2max below 50 ml.kg-1.min-1, tolerance to lower body negative pressure (LBNP) was increased by 28%. Exercise training did not compromise baroreflex functions despite evidence of increased resting vagal cardiac tone and reduced sympathetic tone. In contrast to fainters, increased orthostatic tolerance in the exercised-trained subjects was associated with no alteration in their ability to elevate heart rate, vasoactive hormones, and peripheral resistance at peak LBNP. However, cardiac output and mean arterial blood pressure were maintained during higher submaximal LBNP levels by a 20% increase in stroke volume. The elevation in stroke volume during LBNP after training was associated with blood volume expansion. Although orthostatic tolerance may be reduced in some highly trained endurance athletes, data from this and other longitudinal experiments argue for the notion that orthostatic stability is not compromised by exercise training that does not increase VO2max above a critical threshold (approximately 55-60 ml.kg-1.min-1) and provoke associated cardiovascular adaptations. Since average VO2max of astronauts and pilots fall below this threshold, there is no compelling evidence to suggest that these individuals should refrain from such regular exercise activity. C1 NASA,KENNEDY SPACE CTR,FL 32899. NR 61 TC 61 Z9 62 U1 3 U2 5 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD JUN PY 1993 VL 25 IS 6 BP 705 EP 712 PG 8 WC Sport Sciences SC Sport Sciences GA LG452 UT WOS:A1993LG45200009 PM 8321108 ER PT J AU MACK, GW CONVERTINO, VA NADEL, ER AF MACK, GW CONVERTINO, VA NADEL, ER TI EFFECT OF EXERCISE TRAINING ON CARDIOPULMONARY BAROREFLEX CONTROL OF FOREARM VASCULAR-RESISTANCE IN HUMANS SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE BARORECEPTORS; PHYSICAL FITNESS; BLOOD VOLUME ID BODY NEGATIVE-PRESSURE; VASOCONSTRICTOR RESPONSES; TEMPERATURES; FITNESS; SKIN AB We studied the stimulus-response characteristics of cardiopulmonary baroreflex control of forearm vascular resistance (FVR) in four groups of male volunteer subjects: i) unfit, ii) physically fit, iii) before and after 10 wk of endurance training (chronic blood volume expansion), and iv) before and after acute blood volume expansion. We assessed the relationship between reflex stimulus, i.e., changes in central venous pressure and response, i.e., FVR, during unloading of cardiopulmonary mechanoreceptors with lower body negative pressure (LBNP, 0 to -20 mm Hg). The slope of the linear relationship between FVR and CVP, the index of the responsiveness of this baroreflex, was significantly diminished (>50%) in the fit subjects compared with the unfit. The slope of the FVR-CVP relationship was inversely correlated with the subject's total blood volume, suggesting that blood volume expansion was related to the attenuated CP baroreflex. In the exercise training study, maximal oxygen consumption and blood volume increased following 10 wk of endurance training (N = 14) but were unchanged in the time control group (N = 7). The slope of the FVR-CVP relationship was significantly reduced (32%) following 10 wk of training but was unchanged in the time control group. The reduction in slope of the FVR-CVP relationship was inversely related to the increase in blood volume associated with exercise training. Acute blood volume expansion 8 ml.kg-1 body weight with 5% human serum albumin solution) significantly reduced the slope of the FVR-CVP relationship. These data support the hypothesis that the attenuated forearm vascular reflex in physically fit individuals is related to a training-induced hypervolemia. Training programs that increase maximal aerobic capacity but fail to elicit an increase in blood volume will have minimal effects on cardiopulmonary baroreflex control of FVR. C1 NASA,LIFE SCI RES OFF,KENNEDY SPACE CTR,FL 32899. YALE UNIV,SCH MED,DEPT EPIDEMIOL,NEW HAVEN,CT 06510. YALE UNIV,SCH MED,DEPT CELLULAR & MOLEC PHYSIOL,NEW HAVEN,CT 06510. RP MACK, GW (reprint author), JOHN B PIERCE LAB,290 CONGRESS AVE,NEW HAVEN,CT 06515, USA. NR 29 TC 20 Z9 20 U1 1 U2 1 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD JUN PY 1993 VL 25 IS 6 BP 722 EP 726 PG 5 WC Sport Sciences SC Sport Sciences GA LG452 UT WOS:A1993LG45200011 PM 8321110 ER PT J AU JACOBSON, NS MEHROTRA, GM AF JACOBSON, NS MEHROTRA, GM TI THERMODYNAMICS OF IRON-ALUMINUM ALLOYS AT 1573-K SO METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY LA English DT Article AB The activities of iron (Fe) and aluminum (Al) were measured in Fe-Al alloys at 1573 K using the ion-current-ratio technique in a high-temperature Knudsen cell mass spectrometer. The Fe-Al solutions exhibited negative deviations from ideality over the entire composition range. The activity coefficients gamma(Fe), and gamma(Al) are given by the following equations as a function of mole fraction (x(Fe), x(Al)): 0 < x(Al) < 0.4 ln gamma(Fe) = -4.511(+/-0.008)x(Al)2 In gamma(Al) = -4.462(+/-0.029)x(Fe)2 + 0.325(+/-0.013) 0.6 < x(Al) < 1.0 ln gamma(Fe) = -4.065(+/-0.006)x(Al)2 + 0.099(+/-0.003) ln gamma(Al) = -4.092(+/-0.026)x(Fe)2 + 0.002(+/-0.001) The results showed good agreement with those obtained from previous investigations at other temperatures by extrapolation of the activity data to 1573 K. C1 WRIGHT STATE UNIV,DEPT MECH & MAT ENGN,DAYTON,OH 45435. RP JACOBSON, NS (reprint author), NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135, USA. RI Jacobson, Nathan/A-9411-2009 NR 21 TC 29 Z9 29 U1 2 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2141 J9 METALL TRANS B PD JUN PY 1993 VL 24 IS 3 BP 481 EP 486 DI 10.1007/BF02666431 PG 6 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA LF026 UT WOS:A1993LF02600009 ER PT J AU JONES, RH LOFGREN, GE AF JONES, RH LOFGREN, GE TI A COMPARISON OF FEO-RICH, PORPHYRITIC OLIVINE CONDRULES IN UNEQUILIBRATED CHONDRITES AND EXPERIMENTAL ANALOGS SO METEORITICS LA English DT Article ID PARENT BODY METAMORPHISM; DYNAMIC CRYSTALLIZATION; THERMAL HISTORIES; CHONDRULE MELTS; METEORITES; DIFFUSION; ORIGIN AB Experimentally produced analogues of porphyritic olivine (PO) chondrules in ordinary chondrites provide an important insight into chondrule formation processes. We have studied experimental samples with PO textures grown at three different cooling rates (2, 5 and 100-degrees-C/h), and samples that have been annealed at high temperatures (1000-1200-degrees-C) subsequent to cooling. These are compared with natural chondrules of similar composition and texture from the ordinary chondrites Semarkona (LL3.0) and ALH 81251 (LL3.3). Zoning properties of olivine grains indicate that the Semarkona chondrules cooled at comparable rates to the experiments. Zoning in olivine from chondrules in ALH 81251 is not consistent with cooling alone but indicates that the chondrules underwent an annealing process. Chromium loss from olivine is very rapid during annealing and calculated diffusion coefficients for Cr in olivine are very similar to those of Fe-Mg interdiffusion coefficients under the same conditions. Annealed experimental samples contain an aluminous, low-Ca pyroxene which forms by reaction of olivine and liquid. No similar reaction texture is observed in ALH 81251 chondrules, and this may be evidence that annealing of the natural samples took place at considerably lower temperatures than the experimental analogues. The study supports the model of chondrule formation in a cool nebula and metamorphism of partly equilibrated chondrites during reheating episodes on the chondrite parent bodies. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP JONES, RH (reprint author), UNIV NEW MEXICO,DEPT EARTH & PLANETARY SCI,INST METEORIT,ALBUQUERQUE,NM 87131, USA. NR 22 TC 52 Z9 52 U1 1 U2 5 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD JUN PY 1993 VL 28 IS 2 BP 213 EP 221 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LJ270 UT WOS:A1993LJ27000007 ER PT J AU TREIMAN, AH AF TREIMAN, AH TI AN IMPROBABLE CONCENTRATION OF BASALTIC METEORITE FALLS (HED AND MESOSIDERITE) IN THE MID-20TH CENTURY SO METEORITICS LA English DT Note ID APOLLO-AMOR OBJECTS; PRODUCTION-RATES; EXPOSURE AGES; RARE-GASES; HOWARDITES; DIOGENITES; ASTEROIDS; EUCRITES AB The fall rate of HED basaltic meteorites (howardites, eucrites, diogenites) has not been constant in the 20th century, while the fall rate of chondrites has been constant within error. Thirteen of the 26 dated HED falls (day of fall known, 1900 through 1989) fell in 1924 through 1939. A fall duster (not a meteorite stream) like this will occur in less than one in 100 random distributions of fall days. The proportions of HED types in the whole cluster are statistically identical to those of the whole historical record of HED falls, as is the distribution of cosmic ray exposure ages. In a subset of the duster, 1924 through 1933, eight of those nine HED falls from have exposure ages of 10-20 Ma; this grouping is statistically distinct from that of the historical record. The mesosiderite meteorites share many chemical and isotopic properties with the HEDs but are not from the same parent body. However, the dates of the three mesosiderite falls of the 20th century (all in 1924 through 1939) are a likely sampling of the distribution of HED fall dates; less than one in 200 random distributions of three fall dates would have them all in a given 15 year interval of the 20th century. If the concentration of HED and mesosiderite falls in 1924 through 1939 is not a result of chance (odds of less than 1 in 200), it must have had a cause or causes. Tle cause(s) are not dear but appear(s) to have operated: on parent bodies only of basaltic meteorites; on a number of such parent bodies (mesosiderite and at least one HED); distant from Earth; and so as to produce a cluster of only 15 years duration. This duration is much shorter than the expected time scales for orbital evolution of asteroidal fragments. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 38 TC 6 Z9 6 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD JUN PY 1993 VL 28 IS 2 BP 246 EP 252 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LJ270 UT WOS:A1993LJ27000013 ER PT J AU SINGH, JJ AF SINGH, JJ TI MICROSTRUCTURAL CHARACTERIZATION OF THIN POLYMER-FILMS USING THE LANGLEY LOW-ENERGY POSITRON FLUX GENERATOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 12TH INTERNATIONAL CONF ON THE APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY CY NOV 02-05, 1992 CL UNIV N TEXAS, DENTON, TX SP US DOE, NATL SCI FDN, OAK RIDGE ASSOC UNIV, UNIV N TEXAS HO UNIV N TEXAS ID LIFETIME AB Thin, high-performance polymer films are finding widespread applications in industry, medicine, and aerospace research. Since the microstructure of the films determines how well they meet their theoretical promise, it is necessary to develop efficient techniques for producing reasonable fluxes of low energy positrons needed for investigating thin polymer films. We have developed a highly efficient scheme for generating high fluxes of slow positrons. These positrons have been successfully used to measure lifetimes in the thin test films. The lifetime data have been used to develop two structure-property models for the lest films. The first model relates the free volume cell size (V(f)) with the molecular weight of the polymer repeat unit (M) by an expression of the form V(f) = AM(B), where A and B are structural constants. The second model relates the free volume fraction (f) with the dielectric constant of the polymer film (epsilon) by an expression of the form 1/epsilon = (1 - f )/epsilon(R) + f/epsilon(vac) where epsilon(R) is the dielectric constant of the microvoid-free film. RP SINGH, JJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUN PY 1993 VL 79 IS 1-4 BP 349 EP 352 DI 10.1016/0168-583X(93)95361-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LH984 UT WOS:A1993LH98400095 ER PT J AU EDWARDS, DL WILLIAMS, JR FROMHOLD, AT BARNES, PA WEY, JP NEELY, WC WHITAKER, AF AF EDWARDS, DL WILLIAMS, JR FROMHOLD, AT BARNES, PA WEY, JP NEELY, WC WHITAKER, AF TI THE OXIDATION OF POLYCRYSTALLINE SILVER FILMS BY THERMAL, GROUND-STATE ATOMIC OXYGEN SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID PLASMA AB Experimental results indicate a linear relationship between oxide layer thickness and exposure time for thin Ag films exposed to thermal, ground-state atomic oxygen fluxes of the order of 10(17) atoms/(CM2 s). Exposure times ranged between 10 and 120 s, and all exposures were made at ambient temperature. The techniques of scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) were used to characterize stress-induced damage in the thickest oxide layers. This damage was also observed using RBS (Rutherford backscattering spectroscopy) techniques which were applied to determine oxide layer thicknesses as a function of exposure time. Results are compared with data recently obtained from similar measurements using thin, polycrystalline Cu films. C1 AUBURN UNIV, DEPT PHYS, AUBURN, AL 36849 USA. AUBURN UNIV, DEPT CHEM, AUBURN, AL 36849 USA. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, DIV ENGN PHYS, HUNTSVILLE, AL 35812 USA. NR 14 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X EI 1872-9584 J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD JUN PY 1993 VL 79 IS 1-4 BP 676 EP 679 DI 10.1016/0168-583X(93)95441-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA LH984 UT WOS:A1993LH98400175 ER PT J AU ZHOU, SM YEH, PC LIU, HK AF ZHOU, SM YEH, PC LIU, HK TI DYNAMIC 2-DIMENSIONAL BEAM-PATTERN STEERING TECHNIQUE SO OPTICS LETTERS LA English DT Article AB A dynamic two-dimensional laser-beam-pattern steering technique using photorefractive holograms in conjunction with electrically addressed spatial light modulators is proposed and investigated. The experimental results demonstrate the dynamic steering of random combinations of basis beam patterns. The proposed method has the advantages of random beam-pattern combination, good beam intensity uniformity, and higher diffraction efficiency compared with conventional methods. C1 JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP ZHOU, SM (reprint author), UNIV CALIF SANTA BARBARA,DEPT ELECT & COMP ENGN,SANTA BARBARA,CA 93106, USA. RI Yeh, Pochi/A-2109-2010 NR 10 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 1993 VL 18 IS 11 BP 843 EP 845 DI 10.1364/OL.18.000843 PG 3 WC Optics SC Optics GA LD517 UT WOS:A1993LD51700001 PM 19802290 ER PT J AU PARTOVI, A GLASS, AM CHIU, TH LIU, DTH AF PARTOVI, A GLASS, AM CHIU, TH LIU, DTH TI HIGH-SPEED JOINT-TRANSFORM OPTICAL-IMAGE CORRELATOR USING GAAS/ALGAAS SEMIINSULATING MULTIPLE-QUANTUM WELLS AND DIODE-LASERS SO OPTICS LETTERS LA English DT Article AB We demonstrate a compact real-time optical image correlator using diode lasers and a semi-insulating GaAs/AlGaAs multiple-quantum-well (SI-MQW) device as the holographic element. With only 3 mW of power incident upon the SI-MQW device, the correlation is obtained in 1 mus and can be erased in as fast as 2 mus, which presents the possibility of a system capable of 3 x 10(5) correlations/s. We also show that images can be stored for a controllable length of time (2-25 mus), which presents possibilities for the use of the SI-MQW device as a data or image buffer memory. C1 AT&T BELL LABS,HOLMDEL,NJ 07733. JET PROP LAB,PASADENA,CA 91109. RP PARTOVI, A (reprint author), AT&T BELL LABS,MURRAY HILL,NJ 07974, USA. NR 16 TC 57 Z9 57 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 1 PY 1993 VL 18 IS 11 BP 906 EP 908 DI 10.1364/OL.18.000906 PG 3 WC Optics SC Optics GA LD517 UT WOS:A1993LD51700022 PM 19802311 ER PT J AU DAVIS, BA CARR, HV SCHMIDT, N HICKERSON, L AF DAVIS, BA CARR, HV SCHMIDT, N HICKERSON, L TI OPPORTUNITIES IN THE COMMERCIAL USES OF REMOTE-SENSING AND GIS TECHNOLOGIES - AN OVERVIEW OF NASA VISITING INVESTIGATOR PROGRAM AT STENNIS-SPACE-CENTER SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article C1 SVERDRUP TECHNOL INC,BAY ST LOUIS,MS 39529. SMITH SECKMAN REID INC,MURFREESBORO,TN 37130. RP DAVIS, BA (reprint author), NASA,SCI & TECHNOL LAB,BAY ST LOUIS,MS 39529, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUN PY 1993 VL 59 IS 6 BP 935 EP 939 PG 5 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA LH904 UT WOS:A1993LH90400001 ER PT J AU RIGGAN, PJ BRASS, JA LOCKWOOD, RN AF RIGGAN, PJ BRASS, JA LOCKWOOD, RN TI ASSESSING FIRE EMISSIONS FROM TROPICAL SAVANNA AND FORESTS OF CENTRAL BRAZIL SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID BIOMASS AB Wildfires in tropical forest and savanna are a strong source of trace gas and particulate emissions to the atmosphere, but estimates of the continental-scale impacts are limited by large uncertainties in the rates of fire occurrence and biomass combustion. Satellite-based remote sensing offers promise for characterizing fire physical properties and impacts on the environment, but currently available sensors saturate over high-radiance targets and provide only indications of regions and times at which fires are extensive and their areal rate of growth as recorded in ash layers. Here we describe an approach combining satellite- and aircraft-based remote sensing with in situ measurements of smoke to estimate emissions from central Brazil. These estimates will improve global accounting of radiation-absorbing gases and particulates that may be contributing to climate change and will provide strategic data for fire management. C1 NASA,AMES RES CTR,ECOSYST SCI & TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP RIGGAN, PJ (reprint author), US FOREST SERV,PACIFIC SW RES STN,FOREST FIRE LAB,4955 CANYON CREST DR,RIVERSIDE,CA 92507, USA. NR 23 TC 18 Z9 18 U1 0 U2 1 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD JUN PY 1993 VL 59 IS 6 BP 1009 EP 1015 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA LH904 UT WOS:A1993LH90400012 ER PT J AU OLSON, JR POHL, RO VANDERSANDE, JW ZOLTAN, A ANTHONY, TR BANHOLZER, WF AF OLSON, JR POHL, RO VANDERSANDE, JW ZOLTAN, A ANTHONY, TR BANHOLZER, WF TI THERMAL-CONDUCTIVITY OF DIAMOND BETWEEN 170 AND 1200-K AND THE ISOTOPE EFFECT SO PHYSICAL REVIEW B LA English DT Article ID DIFFUSIVITY AB Measurements on the thermal conductivity of natural and synthetic single-crystal diamond are presented over a wide temperature range. The large isotope effect reported previously has been confirmed. The data have been analyzed using both the Debye model of thermal conductivity, which ignores the N processes, and the Callaway model in the limit that the N processes dominate the phonon scattering. It is found that the observed isotope effect can be accounted for by including the N processes alone, without having to postulate the existence of additional defects. C1 JET PROP LAB,PASADENA,CA 91109. GE CO,CTR RES & DEV,SCHENECTADY,NY 12309. RP OLSON, JR (reprint author), CORNELL UNIV,ATOM & SOLID STATE PHYS LAB,ITHACA,NY 14853, USA. NR 37 TC 109 Z9 109 U1 2 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1993 VL 47 IS 22 BP 14850 EP 14856 DI 10.1103/PhysRevB.47.14850 PG 7 WC Physics, Condensed Matter SC Physics GA LF531 UT WOS:A1993LF53100018 ER PT J AU TANVEER, S SPEZIALE, CG AF TANVEER, S SPEZIALE, CG TI SINGULARITIES OF THE EULER EQUATION AND HYDRODYNAMIC STABILITY SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID FLUID; FLOWS; INSTABILITIES; EVOLUTION AB Equations governing the motion of a specific class of singularities of the Euler equation in the extended complex spatial domain are derived. Under some assumptions, it is shown how this motion is dictated by the smooth part of the complex velocity at a singular point in the unphysical domain. These results are used to relate the motion of complex singularities to the stability of steady solutions of the Euler equation. A sufficient condition for instability is conjectured. Several examples are presented to demonstrate the efficacy of this sufficient condition which include the class of elliptical flows and the Kelvin-Stuart cat's eye. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. RP TANVEER, S (reprint author), OHIO STATE UNIV,DEPT MATH,COLUMBUS,OH 43210, USA. RI Tanveer, Saleh/I-9216-2014 NR 25 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD JUN PY 1993 VL 5 IS 6 BP 1456 EP 1465 DI 10.1063/1.858583 PG 10 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LE356 UT WOS:A1993LE35600022 ER PT J AU CHINFATT, C DESILVA, AW GOLDENBAUM, GC HESS, R COTE, C FILUK, A GAUVREAU, JL HWANG, FK AF CHINFATT, C DESILVA, AW GOLDENBAUM, GC HESS, R COTE, C FILUK, A GAUVREAU, JL HWANG, FK TI FORMATION AND DECAY OF A SPHEROMAK PLASMA SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID MAGNETIC RECONNECTION; CONFIGURATION; RELAXATION; EVOLUTION; HELICITY AB The magnetic properties of the spheromak configuration produced by a combination of slow theta and Z discharges in the University of Maryland Spheromak experiment (MS) are reported. The magnetic structure of the plasma in MS has been mapped out by arrays of passive magnetic pickup coils. The Taylor relaxation process is observed during the formation phase. The magnetic profile evolves in such a way that the ratio of poloidal current I(p) to poloidal flux psi in the plasma approaches a constant value, where mu0I(p) = k(el)psi. When the spheromak is formed, the magnetic field configuration is close to Taylor's minimum energy state, mu0j = kB. This constant k is related to the size of the spheromak produced. A spheromak with 1.0 T maximum field, corresponding to 650 kA poloidal current, has been produced in MS. However, due to the high plasma density (6-8 X 10(20) m-3 ) and the presence of low-Z impurities (mainly carbon and oxygen), the plasma is radiation dominated with electron temperature less-than-or-equal-to 15 eV. The magnetic field decays exponentially during the decay phase. Axisymmetric equilibrium states that could exist in the configuration are calculated with a Grad-Shafranov equilibrium code. Comparison of the numerical calculation with the experimental measurements indicates that the magnetic-field structure stays close to the equilibrium state as the plasma decays. C1 APPL PHYS LAB,LAUREL,MD 20723. NASA,GODDARD SPACE FLIGHT CTR,GSFC,GREENBELT,MD 20771. SANDIA NATL LABS,DIV 1271,ALBUQUERQUE,NM 87185. CCFM,VARENNES J3X 1S1,PQ,CANADA. NATL TAIWAN UNIV,DEPT PHYS,TAIPEI 11718,TAIWAN. RP CHINFATT, C (reprint author), UNIV MARYLAND,PLASMA RES LAB,COLL PK,MD 20742, USA. NR 24 TC 2 Z9 2 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD JUN PY 1993 VL 5 IS 6 BP 1816 EP 1827 DI 10.1063/1.860818 PG 12 WC Physics, Fluids & Plasmas SC Physics GA LF953 UT WOS:A1993LF95300018 ER PT J AU BENNETT, CL BOGGESS, NW CHENG, ES HAUSER, MG KELSALL, T MATHER, JC MOSELEY, SH MURDOCK, TL SHAFER, RA SILVERBERG, RF SMOOT, GF WEISS, R WRIGHT, EL AF BENNETT, CL BOGGESS, NW CHENG, ES HAUSER, MG KELSALL, T MATHER, JC MOSELEY, SH MURDOCK, TL SHAFER, RA SILVERBERG, RF SMOOT, GF WEISS, R WRIGHT, EL TI SCIENTIFIC RESULTS FROM THE COSMIC BACKGROUND EXPLORER (COBE) SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE MICROWAVE; INFRARED ID DIFFERENTIAL MICROWAVE RADIOMETERS; INFLATIONARY UNIVERSE SCENARIO; SCALE ANISOTROPIES; RADIATION; SPECTRUM; LIGHT; PERTURBATIONS; FLUCTUATIONS; BOLOMETERS; FLATNESS AB The National Aeronautics and Space Administration (NASA) has flown the COBE satellite to observe the Big Bang and the subsequent formation of galaxies and large-scale structure. Data from the Far-Infrared Absolute Spectrophotometer (FIRAS) show that the spectrum of the cosmic microwave background is that of a black body of temperature T = 2.73 +/- 0.06 K, with no deviation from a black-body spectrum greater than 0.25% of the peak brightness. The data from the Differential Microwave Radiometers (DMR) show statistically significant cosmic microwave background anisotropy, consistent with a scale-invariant primordial density fluctuation spectrum. Measurements from the Diffuse Infrared Background Experiment (DIRBE) provide new conservative upper limits to the cosmic infrared background. Extensive modeling of solar system and galactic infrared foregrounds is required for further improvement in the cosmic infrared background limits. C1 GEN RES CORP, DANVERS, MA 01923 USA. LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. MIT, DEPT PHYS, CAMBRIDGE, MA 02139 USA. UNIV CALIF LOS ANGELES, DEPT ASTRON, LOS ANGELES, CA 90024 USA. RP BENNETT, CL (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RI Moseley, Harvey/D-5069-2012 NR 104 TC 4 Z9 4 U1 0 U2 2 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 JUN 1 PY 1993 VL 90 IS 11 BP 4766 EP 4773 DI 10.1073/pnas.90.11.4766 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LF285 UT WOS:A1993LF28500002 PM 11607383 ER PT J AU FEIBELMAN, WA AF FEIBELMAN, WA TI THE ULTRAVIOLET-SPECTRUM OF THE PLANETARY-NEBULA VY-2-2 SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID VY 2-2; APPARENT MAGNITUDES; OH-EMISSION; NUCLEI; STARS AB New ultraviolet short-wavelength (SWP) IUE observations for the proto-planetary nebula Vy 2-2 were obtained in the low-dispersion mode. An exposure of 400-min duration reveals a weak stellar continuum and several definite emission lines as well as a number of absorption features. Emission features of C III], Si III], and [Ne III] are clearly observed, while C IV, Si II, and possibly C II appear in absorption. Emission features of He II, O III], and Al III are also indicated, though less certain. The UV spectrum tends to confirm that Vy 2-2 is a young, dense planetary nebula excited by a central star with T(eff) > 60,000 K. RP FEIBELMAN, WA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6841,GREENBELT,MD 20771, USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JUN PY 1993 VL 105 IS 688 BP 595 EP 598 DI 10.1086/133201 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LJ333 UT WOS:A1993LJ33300009 ER PT J AU ARQUILLA, R AF ARQUILLA, R TI PERIODICITIES IN THE IUE PARTICLE RADIATION DATA SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID GEOMAGNETIC-ACTIVITY; SECTOR STRUCTURE; HOT-SPOTS; SOLAR; FLARES; ELECTRONS; PERIOD; ZONES; SUN AB The magnetospheric charged particle flux measured serendipitously by the IUE satellite during perigee passages from 1978 February to 1989 February has been searched for periodicities using Fourier transform and correlation techniques. The analysis uncovers persistent modulations of the particle flux with periods of 28-33 days and 15-17 days. The particle flux seen by IUE in the outer van Allen belt is modulated to a significant extent by the magnetosphere's interaction with high-speed solar wind streams from coronal holes, in agreement with analyses of fluxes at other altitudes and of geomagnetic disturbance indices. It is suggested that recurrent global solar-surface activity, such as the 25.8-day periodicity discussed by Bai and Sturrock (1991, Nature, 350, 141) and the solar ''hot spots'' reported by Bai (1987, ApJ, 314, 795; 1988, ApJ, 328, 860; 1990, ApJ, 364, L17), may play a role in modulating the particle flux near solar maximum. RP ARQUILLA, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,IUE OBSERV,COMP SCI CORP,ASTRON PROGRAMS,CODE 6849,GREENBELT,MD 20771, USA. NR 32 TC 0 Z9 0 U1 1 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JUN PY 1993 VL 105 IS 688 BP 603 EP 609 DI 10.1086/133203 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LJ333 UT WOS:A1993LJ33300011 ER PT J AU LARSON, DJ SILBERSTEIN, RP DIMARZIO, D CARLSON, FC GILLIES, D LONG, G DUDLEY, M WU, J AF LARSON, DJ SILBERSTEIN, RP DIMARZIO, D CARLSON, FC GILLIES, D LONG, G DUDLEY, M WU, J TI COMPOSITIONAL, STRAIN CONTOUR AND PROPERTY MAPPING OF CDZNTE BOULES AND WAFERS SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON MERCURY CADMIUM TELLURIDE CHARACTERIZATION CY OCT 15-16, 1992 CL DANVERS, MA SP NIST AB We have developed detailed non-destructive mapping and spatial imaging techniques for comparing boule and wafer properties with analytical predictions from high-fidelity process models for seeded vertical Bridgman-Stockbarger growth of CdZnTe crystals. We have emphasized the prediction of the magnitude and distribution of residual stress and strain, as well as longitudinal and radial segregation within the boules and across wafers cut from the boules. Boule and wafer compositional distributions were mapped using photoreflectance, precision lattice parameter measurements and FTIR spectroscopy. Defect and strain distributions within the boules and wafers were imaged using synchrotron topography, synchrotron strain contour mapping, and double-crystal rocking-curve mapping Thermomechanical and thermosolutal models specifically addressing the seeded vertical Bridgman-Stockbarger growth of CdZnTe crystals were developed and empiricized. These models addressed solute redistribution and stress generation as a result of the interface shape, aspect ratio and growth parameters during the seeding, initial transient (including the shoulder), steady-state and terminal transient regions of the boule Finally, the stress and strain distributions on specific wafers 'cut' from the processed (modelled) boules were predicted and x-ray synchrotron strain contour, double-crystal rocking-curve, FTIR, and photoreflectance maps were generated on the real wafers for comparison. Implications of these results with respect to substrate quality, screening, performance and producibility, will be discussed. C1 CLARKSON UNIV,POTSDAM,NY 13676. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. SUNY,STONY BROOK,NY 11794. NIST,GAITHERSBURG,MD 20899. RP LARSON, DJ (reprint author), GRUMMAN AEROSP CORP,CORP RES CTR,BETHPAGE,NY 11714, USA. NR 6 TC 8 Z9 8 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD JUN PY 1993 VL 8 IS 6 SU S BP 911 EP 915 DI 10.1088/0268-1242/8/6S/010 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA LL644 UT WOS:A1993LL64400011 ER PT J AU MUELLER, RL AF MUELLER, RL TI SPECTRAL RESPONSE MEASUREMENTS OF 2-TERMINAL TRIPLE-JUNCTION A-SI SOLAR-CELLS SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article AB A method of measuring the spectral response of each component junction in a two-terminal triple-junction a-Si solar cell has been developed. The method uses a white bias light and off-the-shelf optical interference filters selected to reduce the bias light encountering each component junction. The a-Si top junction is measured when the cell is biased with wavelengths of 585-1100 nm, the a-Si middle junction is measured when the cell is biased with wavelengths of 350-505 nm and 795-1100 nm and the a-SiGe bottom junction is measured when the cell is biased with wavelengths of 380-670 nm. In turn, the chopped light from a monochromator is used to measure the spectral response of the low-biased junctions. Spectral response curves of the Solarex a-Si/a-Si/a-SiGe triple junction solar cell are presented. In addition, the AM0 I(sc) (short circuit current) of this individual cell type is confirmed to be within +/-2% of the I(sc) obtained when the spectral response of the current limiting junction is integrated with either the AM0 spectral irradiance or that of a closely matched (+/-10% from 350 nm to 900 nm) X-25 Mark II solar simulator. RP MUELLER, RL (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 5 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD JUN PY 1993 VL 30 IS 1 BP 37 EP 45 DI 10.1016/0927-0248(93)90029-3 PG 9 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA LM913 UT WOS:A1993LM91300004 ER PT J AU VALENTINE, MJ BROWN, LL GOLOMBEK, MP AF VALENTINE, MJ BROWN, LL GOLOMBEK, MP TI CENOZOIC CRUSTAL ROTATIONS IN THE MOJAVE DESERT FROM PALEOMAGNETIC STUDIES AROUND BARSTOW, CALIFORNIA SO TECTONICS LA English DT Article ID SOUTHERN-CALIFORNIA; TECTONIC ROTATION; NORTH-AMERICA; SIERRA-NEVADA; FAULTS; EXTENSION; BLOCK; MODEL; SHEAR AB Paleomagnetic data from the Mojave Desert around Barstow, California suggest 55-degrees to 75-degrees of clockwise rotation of this area in earliest Miocene time, followed by 23-degrees of counterclockwise rotation in the Early Miocene, and no rotation after 18 Ma. Earliest Miocene clockwise rotation of the Barstow area is suggested by data from nine sites in the Oligocene-Miocene Lane Mountain Quartz Latite and Jackhammer Formation and may be related to oroclinal bending of the southern Sierra Nevada batholith. Data from 13 sites in the Early Miocene Pickhandle Formation indicate counterclockwise rotation, which coincides with Early Miocene E-NE - W-SW extension and detachment faulting in the Mojave Desert. Other parts of the Mojave Desert experienced variable senses and amounts of rotation at this time which may be related to drag along transfer zones within the upper plate, while the lower plate was not rotated. These results suggest that Miocene extension in the Mojave Desert is related to similarly oriented extension in the Colorado River extensional corridor. Early Miocene to Pliocene rocks of the Andesite and Dacite of the Calico Mountains, Barstow Formation, Andesite of Murphy's Well, and Black Mountain Basalt show no evidence for significant rotation of the Barstow area after 18 Ma. Most other paleomagnetic data from elsewhere in the Mojave are consistent with a lack of significant post-18 Ma rotations, suggesting that post-10 Ma right-lateral faulting there has produced relatively little crustal rotation. The exception to this generalization is the northeast comer of the Mojave Desert which underwent substantial post-18 Ma clockwise rotation. Paleomagnetic flattening data also indicate that post-Oligocene N-S translation of crustal blocks in the Mojave Desert has been insignificant. C1 UNIV MASSACHUSETTS,DEPT GEOL & GEOG,AMHERST,MA 01003. JET PROP LAB,DEPT EARTH & SPACE SCI,PASADENA,CA 91109. RP VALENTINE, MJ (reprint author), UNIV PUGET SOUND,DEPT GEOL,TACOMA,WA 98416, USA. NR 52 TC 13 Z9 13 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0278-7407 J9 TECTONICS JI Tectonics PD JUN PY 1993 VL 12 IS 3 BP 666 EP 677 DI 10.1029/92TC02813 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LG198 UT WOS:A1993LG19800005 ER PT J AU KOBLINSKY, CJ CLARKE, RT BRENNER, AC FREY, H AF KOBLINSKY, CJ CLARKE, RT BRENNER, AC FREY, H TI MEASUREMENT OF RIVER LEVEL VARIATIONS WITH SATELLITE ALTIMETRY SO WATER RESOURCES RESEARCH LA English DT Article ID GREENLAND ICE-SHEET; GROWTH AB Quantitative assessment of water levels and river discharge is often made difficult by large distances, limited access, and low population densities in remote areas. Satellite altimetry provides a repetitive remote sensing approach to determining river levels at a number of locations within a river system, providing the orbital repeat cycle is short enough in time, the ground track maintains a stable repeat over previous locations, and the return power of the altimeter signal can be readily identified and located. The U.S. Navy's Geosat radar altimeter mission between 1985 and 1989 provided the first altimeter measurements with sufficient precision and extended duration to examine the utility of such measurements for long-term monitoring of inland waters. These measurements have been examined over the Amazon basin. Satellite observations are retrieved at four locations that overlap with river gauge measurements. A technique is developed to isolate radar return signals from the river. Two years of satellite measurements are compared with the river gauge retrievals. The overall level of comparison is 0.7 m rms when the technique is applied manually, and 1.2 m rms when an automated version of the method is applied. At one location the average difference is 0.2 m rms. This level of accuracy may not be useful for routine hydrological measurements. However, there are a variety of difficulties that are specific to the Geosat altimeter measurement over rough terrain. Present altimeter satellites, ERS 1 (launched June 1991) and TOPEX/Poseidon (launched August 1992), correct many of these problems. This study suggests that the prospect for obtaining useful measurements of river level from space is promising. C1 UNIV FED RIO GRANDE SUL,BR-90040 PORTO ALEGRE,RS,BRAZIL. HUGHES STX CORP,LANHAM,MD 20706. RP KOBLINSKY, CJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 971,GREENBELT,MD 20771, USA. NR 21 TC 96 Z9 102 U1 1 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 1993 VL 29 IS 6 BP 1839 EP 1848 DI 10.1029/93WR00542 PG 10 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA LE495 UT WOS:A1993LE49500031 ER PT J AU GEORGE, T FOOTE, MC VASQUEZ, RP FORTIER, EP POSTHILL, JB AF GEORGE, T FOOTE, MC VASQUEZ, RP FORTIER, EP POSTHILL, JB TI BELOW BAND-GAP LASER ABLATION OF DIAMOND FOR TRANSMISSION ELECTRON-MICROSCOPY SO APPLIED PHYSICS LETTERS LA English DT Article AB A 248 nm excimer laser was used to thin naturally occurring type 1a diamond substrates at normal and glancing (22-degrees) incidence. Perforation of a 250-mum-thick substrate was achieved in about 15 min at normal incidence. While the substrate thinned at glancing incidence was found to have large electron-transparent areas, that thinned at normal incidence required additional argon-ion milling to achieve electron transparency. X-ray photoelectron spectroscopy of the back surface of the diamond failed to detect any graphite or glassy carbon, confirming that damage due to laser ablation occurs only at the incident surface. Samples prepared using this technique imaged in the transmission electron microscope were observed to have retained the nitrogen platelets characteristic of such type 1a diamonds. C1 RES TRIANGLE INST,RES TRIANGLE PK,NC 27709. RP GEORGE, T (reprint author), JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 8 TC 3 Z9 3 U1 2 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1993 VL 62 IS 22 BP 2880 EP 2882 DI 10.1063/1.109188 PG 3 WC Physics, Applied SC Physics GA LE353 UT WOS:A1993LE35300047 ER PT J AU MCCORMICK, MP AF MCCORMICK, MP TI HOT PAPERS - ATMOSPHERIC SCIENCE - SAGE-II MEASUREMENTS OF EARLY PINATUBO AEROSOLS - MCCORMICK,M.P., VEIGA,R.E. SO SCIENTIST LA English DT Article AB HOT PAPERS: An atmospheric scientist discusses the atmospheric and climatological effects of the eruption of Mount Pinatubo. RP MCCORMICK, MP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU SCIENTIST INC PI PHILADELPHIA PA 3600 MARKET ST SUITE 450, PHILADELPHIA, PA 19104 SN 0890-3670 J9 SCIENTIST JI Scientist PD MAY 31 PY 1993 VL 7 IS 11 BP 16 EP 16 PG 1 WC Information Science & Library Science; Multidisciplinary Sciences SC Information Science & Library Science; Science & Technology - Other Topics GA LD906 UT WOS:A1993LD90600012 ER PT J AU RIND, D AF RIND, D TI CLIMATE SYSTEM MODELING - TRENBERTH,KE SO NATURE LA English DT Book Review RP RIND, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 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 27 PY 1993 VL 363 IS 6427 BP 312 EP 312 DI 10.1038/363312a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA LD917 UT WOS:A1993LD91700038 ER PT J AU GREBOWSKY, JM KASPRZAK, WT HARTLE, RE MAHAJAN, KK WAGNER, TCG AF GREBOWSKY, JM KASPRZAK, WT HARTLE, RE MAHAJAN, KK WAGNER, TCG TI SUPERTHERMAL IONS DETECTED IN VENUS DAYSIDE IONOSHEATH, IONOPAUSE, AND MAGNETIC BARRIER REGIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ORBITER AB A comprehensive morphological analysis of the dayside superthermal ion presence in the dayside ionopause region of Venus was made using the Orbiter Ion Mass Spectrometer (OIMS) measurements. Superthermal O+ ions with energies ranging from approximately 15 to 90 eV relative to the spacecraft are observed on essentially every orbit of Pioneer Venus that penetrates into the dayside ionosphere. There is a strong inbound-outbound difference in both the number and intensity of the superthermal ions with most events detected on the inbound crossing of the ionopause. This is consistent with a net flow of plasma along the ionopause away from the subsolar region. The ambient energy (including thermal and/or bulk motions) of the detected ions is comparable to the ram energy of cold ions relative to the moving spacecraft. A comparison of the locations of the superthermal O+ ion occurrences with respect to other parameters shows that the superthermals are a characteristic of the ionopause transition separating the essentially stationary ionosphere plasma from the flowing ionosheath plasma as deduced by Taylor et al. (1980b) from individual examples. These superthermal ions are not often detected within the main ionosphere in the midday region. Except in a few rare instances of changing interplanetary magnetic field (IMF) conditions or at locations near the terminator, they are only present at altitudes within or above the magnetic barrier. The OIMS also detects superthermal H+ ions with an inbound outbound asymmetry in the ionosheath consistent with shocked ionosheath proton flows. C1 NATL PHYS LAB,NEW DELHI 110012,INDIA. TCG INC,ROCKVILLE,MD 20850. RP GREBOWSKY, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Grebowsky, Joseph/I-7185-2013 NR 20 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1993 VL 98 IS E5 BP 9055 EP 9064 DI 10.1029/93JE00300 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LD845 UT WOS:A1993LD84500001 ER PT J AU MCNAMEE, JB BORDERIES, NJ SJOGREN, WL AF MCNAMEE, JB BORDERIES, NJ SJOGREN, WL TI VENUS - GLOBAL GRAVITY AND TOPOGRAPHY SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HARMONIC-ANALYSIS; APHRODITE TERRA; ORBITER AB A new gravity field determination that has been produced combines both the Pioneer Venus Orbiter (PVO) and the Magellan Doppler radio data. Comparisons between this estimate, a spherical harmonic model of degree and order 21, and previous models show that significant improvements have been made. Results are displayed as gravity contours overlaying a topographic map. We also calculate a new spherical harmonic model of topography based on Magellan altimetry, with PVO altimetry included where gaps exist in the Magellan data. This model is also of degree and order 21, so in conjunction with the gravity model, Bouguer and isostatic anomaly maps can be produced. These results are very consistent with previous results, but reveal more spatial resolution in the higher latitudes. RP MCNAMEE, JB (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 TC 20 Z9 20 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1993 VL 98 IS E5 BP 9113 EP 9128 DI 10.1029/93JE00382 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LD845 UT WOS:A1993LD84500006 ER PT J AU HARRIS, AW AF HARRIS, AW TI CORVID METEOROIDS ARE NOT EJECTA FROM THE GIORDANO BRUNO IMPACT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB Hartung (this issue) has suggested that the Corvid meteor stream, observed only once in 1937, may be the return of a clump of ejecta from the formation of a lunar crater, specifically an event recorded in the chronicles of Gervase of Canterbury on June 25, 1178, which Hartung (1976) has previously suggested may be an eyewitness account of the formation of the lunar crater Giordano Bruno. On the basis of this association, he predicts that another Corvid shower may be observed in 2003 or 2006. In this reply, I point out three difficulties with the hypothesis: (1) it is implausible that a clump of ejecta could be launched into heliocentric orbit with a low enough dispersion in velocity among separate pieces that it would produce a meteor shower in just one year and not others; (2) subsequent perturbations by the Earth on parts of the clump passing near the Earth but not impacting, would destroy the coherence of the clump on a time scale much shorter than the 759-year interval proposed; and (3) all else accepted, there are so many possible orbits that could yield a shower after 759 years that it is unlikely that a prediction of a return in a specific year would be correct. RP HARRIS, AW (reprint author), JET PROP LAB,4800 OAK GROVE DR,MS 183-501,PASADENA,CA 91109, USA. NR 2 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1993 VL 98 IS E5 BP 9145 EP 9149 DI 10.1029/93JE00115 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LD845 UT WOS:A1993LD84500009 ER PT J AU HARRIS, AW AF HARRIS, AW TI CORVID METEOROIDS ARE NOT EJECTA FROM THE GIORDANO BRUNO IMPACT - COMMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Note RP HARRIS, AW (reprint author), JET PROP LAB,4800 OAK GROVE DR,MS 183-501,PASADENA,CA 91109, USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1993 VL 98 IS E5 BP 9153 EP 9153 DI 10.1029/93JE00117 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LD845 UT WOS:A1993LD84500011 ER PT J AU WEIZER, VG FATEMI, NS AF WEIZER, VG FATEMI, NS TI SIMPLE, EXTREMELY LOW RESISTANCE CONTACT SYSTEM TO N-INP THAT DOES NOT EXHIBIT METAL-SEMICONDUCTOR INTERMIXING DURING SINTERING SO APPLIED PHYSICS LETTERS LA English DT Article ID OHMIC CONTACTS; GAAS AB Contact formation to InP is plagued by the violent metal-semiconductor intermixing that takes place during the contact sintering process. We have discovered a truly unique contact system, involving Au and Ge, which is easily fabricated, which exhibits extremely low values of contact resistivity, and in which there is virtually no metal-semiconductor interdiffusion, even after extended sintering. We present a description of this contact system and suggest possible mechanisms to explain the observed behavior. C1 SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,CLEVELAND,OH 44135. RP WEIZER, VG (reprint author), NASA,LEWIS RES CTR,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 24 PY 1993 VL 62 IS 21 BP 2731 EP 2733 DI 10.1063/1.109247 PG 3 WC Physics, Applied SC Physics GA LD123 UT WOS:A1993LD12300046 ER PT J AU STOTHERS, RB AF STOTHERS, RB TI IMPACT CRATERING AT GEOLOGIC STAGE BOUNDARIES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EXTINCTION; HISTORY; ROCKS; CANADA; EVENT AB The largest known Cenozoic impact craters with the most accurately measured ages are found to correlate very closely with geologic stage boundaries. The level of confidence in this result is 98-99 % even under the most pessimistic assumptions concerning dating errors. One or more large impacts may have led, in at least some cases, to the extinctions and first appearances of biotic species that mark many of the geologic stage boundaries. RP STOTHERS, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,GREENBELT,MD 20771, USA. NR 33 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 21 PY 1993 VL 20 IS 10 BP 887 EP 890 DI 10.1029/93GL00907 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LE448 UT WOS:A1993LE44800003 ER PT J AU MCGEE, TJ GROSS, M FERRARE, R HEAPS, W SINGH, U AF MCGEE, TJ GROSS, M FERRARE, R HEAPS, W SINGH, U TI RAMAN DIAL MEASUREMENTS OF STRATOSPHERIC OZONE IN THE PRESENCE OF VOLCANIC AEROSOLS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DIFFERENTIAL-ABSORPTION-LIDAR AB Since the eruption of Mt. Pinatubo in June, 1991, measurements of atmospheric species which depend on Rayleigh scattering of radiation, have been severely compromised where the volcanic aerosol cloud exists. For the GSFC stratospheric ozone lidar, this has meant that ozone determination has been impossible below approximately 30 km. The GSFC lidar has been modified to detect Raman scattering from nitrogen molecules from transmitted laser wavelengths. The instrument transmits two laser wavelengths at 308 nm and 351 nm, and detects returns at four wavelengths; 308 nm, 332 nm, 351 nm, and 382 nm. Using this technique in conjunction with the Rayleigh DIAL measurement, ozone profiles have been measured between 15 and 50 km. RP MCGEE, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. RI McGee, Thomas/G-4951-2013 NR 10 TC 57 Z9 57 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 21 PY 1993 VL 20 IS 10 BP 955 EP 958 DI 10.1029/93GL00751 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LE448 UT WOS:A1993LE44800020 ER PT J AU GANGULI, SB MITCHELL, HG PALMADESSO, PJ AF GANGULI, SB MITCHELL, HG PALMADESSO, PJ TI PLASMA DYNAMICS DRIVEN BY FINITE-WIDTH CURRENT FILAMENT AND KV POTENTIAL DROPS IN IONOSPHERE-MAGNETOSPHERE COUPLING SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TRANSPORT; FIELDS AB We have simulated the plasma dynamics of a quasi-two-dimensional current filament in ionosphere-magnetosphere coupling. The simulation consists of a set of one-dimensional flux tube simulations with different imposed time-dependent, field-aligned currents. The dynamical interactions of the individual current filaments with the ionospheric and magnetospheric plasma generate kV field-aligned potential drops along the field lines, and the side-by-side display exhibits the evolution of the implied potential structure in the horizontal direction. The primary cross-field motion produced by the horizontal E-field (ExB drift) is perpendicular to both of the significant spatial directions, and is thus ignorable in this geometry. The effects of other cross-field drift processes axe discussed. The simulation thus provides insight into the dynamical evolution of 2D potential structures driven by an imposed finite-width field-aligned current profile. Spatial and temporal variation of other plasma parameters (temperatures, density, etc.) that are determined primarily by parallel transport effects axe also displayed. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. USN,RES LAB,WASHINGTON,DC 20375. RP GANGULI, SB (reprint author), SCI APPLICAT INT CORP,1710 GOODRIDGE DR,MCLEAN,VA 22102, USA. NR 12 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 21 PY 1993 VL 20 IS 10 BP 975 EP 978 DI 10.1029/93GL00848 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LE448 UT WOS:A1993LE44800025 ER PT J AU BENSADOUN, M BERSANELLI, M DEAMICI, G KOGUT, A LEVIN, SM LIMON, M SMOOT, GF WITEBSKY, C AF BENSADOUN, M BERSANELLI, M DEAMICI, G KOGUT, A LEVIN, SM LIMON, M SMOOT, GF WITEBSKY, C TI MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND TEMPERATURE AT 1.47 GHZ SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; COSMOLOGY, OBSERVATIONS ID RADIATION TEMPERATURE; PRECISE MEASUREMENT; 1.32 MILLIMETERS; 3.8 GHZ; SPECTRUM; FREQUENCY; CN; CENTIMETERS; WAVELENGTH; UNIVERSE AB We have used a radio-frequency-gain total-power radiometer to measure the intensity of the cosmic microwave background (CMB) at a frequency of 1.47 GHz (20.4 cm wavelength) from White Mountain, California in 1988 September and from the South Pole, Antarctica in 1989 December. The CMB thermodynamic temperature, T(CMB), is 2.27 +/- 0.25 K (68% confidence limit) measured from White Mountain and 2.26 +/- 0.20 K from the South Pole site. The combined result is 2.26 +/- 0.19 K. The correction for Galactic emission has been derived from scaled low-frequency maps and constitutes the main source of error. The atmospheric signal is extrapolated from our zenith scan measurements at higher frequencies. These results are consistent with our previous measurement at 1.41 GHz (Levin et al. 1988) and approximately 2.5 sigma from the 2.74 +/- 0.01 K global average CMB temperature. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. CNR,IST FIS COSM,I-20133 MILAN,ITALY. RP BENSADOUN, M (reprint author), UNIV CALIF BERKELEY,SPACE SCI LAB,MS 50351,BERKELEY,CA 94720, USA. RI Kogut, Alan/D-6293-2012 NR 42 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 1 EP 13 DI 10.1086/172637 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800001 ER PT J AU HUNTER, SD BERTSCH, DL DINGUS, BL FICHTEL, CE HARTMAN, RC KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF MOLLER, P VONMONTIGNY, C NOLAN, PL PINKAU, K RADECKE, HD ROTHERMEL, H SHAVER, P SCHNEID, E SOMMER, M SREEKUMAR, P THOMPSON, DJ AF HUNTER, SD BERTSCH, DL DINGUS, BL FICHTEL, CE HARTMAN, RC KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF MOLLER, P VONMONTIGNY, C NOLAN, PL PINKAU, K RADECKE, HD ROTHERMEL, H SHAVER, P SCHNEID, E SOMMER, M SREEKUMAR, P THOMPSON, DJ TI DETECTION OF HIGH-ENERGY GAMMA-RAYS FROM QUASAR PKS 0528+134 BY EGRET ON THE COMPTON-GAMMA-RAY-OBSERVATORY SO ASTROPHYSICAL JOURNAL LA English DT Article DE QUASARS, INDIVIDUAL (PKS 0528+134); GAMMA RAYS, OBSERVATIONS ID EXTRAGALACTIC RADIO-SOURCES; X-RAY; TELESCOPE; GHZ; POLARIZATIONS; RADIATION; SPECTRA AB The first several pointing directions of the Compton Gamma Ray Observatory, launched on 1991 April 5, were toward the Galactic anticenter. In addition to the known gamma-ray sources, Crab (PSR 0531 + 21) and Geminga (2CG 195 + 04), high-energy gamma-ray emission (30 MeV to over 1 GeV) was observed from the quasar PKS 0528 + 134 by the Energetic Gamma Ray Experiment Telescope (EGRET). A redshift measurement, reported here, of 2.07 confirms the identification of this object as a quasar. The differential photon spectrum is well represented by a power law with an exponent of 2.56 +/- 0.09 and a photon intensity above 100 MeV of (8.4 +/- 1.0) x 10(-7) photons cm-2 s-1. There is evidence for time variability on a time scale of a few days. C1 MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,CSC,COMPTON SCI SUPPORT CTR,GREENBELT,MD 20771. EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. HAMPDEN SYDNEY COLL,HAMPDEN SYDNEY,VA 23943. STANFORD UNIV,HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. RP HUNTER, SD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; OI Thompson, David/0000-0001-5217-9135; Dingus, Brenda/0000-0001-8451-7450 NR 29 TC 76 Z9 76 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 134 EP 138 DI 10.1086/172648 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800012 ER PT J AU MAZZARELLA, JM GRAHAM, JR SANDERS, DB DJORGOVSKI, S AF MAZZARELLA, JM GRAHAM, JR SANDERS, DB DJORGOVSKI, S TI MOLECULAR GAS IN POWERFUL RADIO GALAXIES DETECTED BY IRAS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ISM; INFRARED, GALAXIES; ISM, MOLECULES; RADIO CONTINUUM, GALAXIES ID INFRARED BRIGHT GALAXIES; ATOMIC-HYDROGEN; HOST GALAXY; CENTAURUS-A; 4C 12.50; H-I; QUASAR; LUMINOSITY; SAMPLE; MORPHOLOGY AB Results are presented from the first phase of a CO(J = 1 --> 0) line survey of powerful radio galaxies (log P408 MHz greater than or similar to 23.5 W Hz-1). Eight radio galaxies detected by IRAS have been observed to a sensitivity limit of approximately 1.0 mK rms (45 km s-1 resolution) using the new 3 mm SIS receiver on the NRAO 12 m telescope; five sources were detected. These observations include the CO detection of the highly variable, compact flat-spectrum radio galaxy 3C 120, detections of four galaxies from the Bologna B2 radio sample, and establishment of sensitive upper limits on the molecular gas content of the very powerful radio galaxies 4C 29.30, 3C 321, and Cygnus A (3C 405). These data have doubled the number of CO detections of powerful radio galaxies, allowing us to begin exploration of the full range of CO luminosities characteristic of this class of objects. The range of computed molecular gas masses, log M(H-2)/M. = 9.42 - 10.34, is approximately 1-7 times the H-2 mass of the Milky Way and is in stark contrast to the low molecular gas masses found in radio-quiet far-infrared-selected elliptical galaxies, log M(H-2)/M. approximately 7-8. The relatively high CO detection rate for the current sample suggests that rich supplies of molecular gas may be ubiquitous in powerful radio-selected galaxies detected by IRAS. The infrared luminosity to molecular gas mass ratio, L(ir)/M(H-2), in powerful radio galaxies observed in CO is in the range approximately 15 L. M-1 to > 100 L. M-1, typical of the range of values found in infrared-luminous nuclear starbursts and AGNs. The CO(J = 1 --> 0) line widths of 3C 120, B2 0722 + 300, and B2 1318 + 343 are very broad (FWZI greater than or similar to 500 km s-1) compared to normal galaxies, but consistent with previously observed interacting/merging galaxies. The CO profile for B2 1506 + 345 is bimodal; both components of this galaxy pair each contain approximately 10(10) M. of molecular gas. The new CO observations support the hypothesis that powerful radio galaxies originate in colliding disk galaxies which evolve into gas-rich, peculiar E/SO galaxies during the merger process. C1 UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. CALTECH,DEPT ASTRON,PASADENA,CA 91125. CALTECH,DIV PHYS MATH & ASTRON,PASADENA,CA 91125. RP MAZZARELLA, JM (reprint author), JET PROP LAB,CTR INFRARED PROC & ANAL,MS 100-22,PASADENA,CA 91109, USA. NR 56 TC 52 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 170 EP 178 DI 10.1086/172653 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800017 ER PT J AU BRUHWEILER, FC BOGGESS, A NORMAN, DJ GRADY, CA URRY, CM KONDO, Y AF BRUHWEILER, FC BOGGESS, A NORMAN, DJ GRADY, CA URRY, CM KONDO, Y TI THE GALACTIC HALO AND LOCAL INTERGALACTIC MEDIUM TOWARD PKS-2155-304 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL LACERTAE OBJECTS, INDIVIDUAL (PKS-2155-304); GALAXY, HALO; INTERGALACTIC MEDIUM; QUASARS, ABSORPTION LINES ID OBJECT PKS 2155-304; ALPHA FOREST; ABSORPTION; RESOLUTION; REDSHIFT; SPECTRA; QSOS; GAS AB The first HST GHRS spectra of the bright BL Lacertae object PKS 2155-304, acquired using the G140L configuration, show a smooth, featureless continuum with superposed sharp absorption. This absorption is due to both gas in the Galactic halo above the south Galactic pole and what are identified as five to six low redshift Lyalpha absorption systems arising in the local intergalactic medium. Complex absorption features of C IV indicate highly ionized gas at near zero velocity and almost-equal-to -260 km s-1 falling toward the Galactic plane. The identified Lyalpha systems cover a range of redshift 0.057 less-than-or-equal-to z less-than-or-equal-to 0.107. These observations confirm two features and rule out two others that were previously identified in summed IUE spectra of PKS 2155-304. The GHRS data resolve the strongest Lyalpha feature previously detected in the IUE data into three distinct components within the interval z = 0.055-0.057. A galaxy within 14' in the plane of the sky to PKS 2155 - 304 with the same measured redshift as that of inferred Lyalpha absorption at z almost-equal-to 0.017 may indicate that this gas is associated with a galaxy cluster. The highest redshift observed Lyalpha system provides a lower limit to the distance of the BL Lacertae object (z > 0.105). This distance is consistent with the approximate redshift deduced from CCD imagery of the probable host galaxy for PKS 2155 - 304 (z approximately 0. 1 2). The Lyalpha systems seen toward PKS 2155-304 are compared to those in the line of sight to 3C 273. A two-point correlation analysis shows no statistical evidence of clustering of Lyalpha features. However, apparent redshift correlations with galaxies along the line of sight argue that some significant fraction of the observed Lyalpha systems are associated with galaxies or galaxy clusters. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,CSC,GODDARD HIGH RESOLUT SPECTROGRAPH,INSTRUMENT DEFINIT TEAM,GREENBELT,MD 20771. RP BRUHWEILER, FC (reprint author), CATHOLIC UNIV AMER,DEPT PHYS,ASTROPHYS PROGRAM,WASHINGTON,DC 20064, USA. RI Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 27 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 199 EP 204 DI 10.1086/172656 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800020 ER PT J AU BARING, MG ELLISON, DC JONES, FC AF BARING, MG ELLISON, DC JONES, FC TI THE INJECTION AND ACCELERATION OF PARTICLES IN OBLIQUE SHOCKS - A UNIFIED MONTE-CARLO DESCRIPTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCELERATION OF PARTICLES; HYDRODYNAMICS; SHOCK WAVES ID COSMIC-RAYS; SUPERNOVA-REMNANTS; MAXIMUM ENERGY; BOW SHOCK; WAVES; SIMULATIONS; UPSTREAM; ORIGIN; PLASMA; FIELD AB Standard Fermi particle acceleration may, for certain shock parameters, be enhanced in oblique shocks, in which the upstream magnetic field makes a significant angle THETA(Bn1) to the shock normal, compared to parallel ones (THETA(Bn1) approximately 0). However, the complexity of oblique shocks has prevented, until now, any determination of the efficiency of the injection and acceleration process (apart from extremely limited hybrid plasma simulation results; e.g., Burgess 1989). As a first step in producing a self-consistent model capable of simultaneously describing shock structure and particle acceleration in shocks of arbitrary obliquity, we have generalized a Monte Carlo simulation, previously used for parallel shocks, to describe oblique geometries. Here we present initial results showing how the injection and acceleration efficiency varies with Mach number and obliquity. In this report we consider only test particles (the shock remains discontinuous on the scale of a particle's mean free path) drawn from the upstream thermal distribution and neglect cross-field diffusion. We show that, for high Mach number parallel shocks, significant numbers of these thermal test particles are drawn (''injected'') into the acceleration process, but that the injection efficiency drops rapidly as THETA(Bn1) increases. For sonic Mach numbers above approximately 20, the fraction of energy density in superthermal particles falls from approximately 97% when THETA(Bn1) = 0-degrees to approximately 30% when THETA(Bn1) = 25-degrees. At low Mach numbers (below M(s) approximately 3) the energy density in superthermal particles drops from approximately 87% to approximately 72% as THETA(Bn1) increases from 0-degrees to 25-degrees. These test-particle results suggest that the acceleration efficiency may be too low in oblique shocks to explain cosmic-ray production in most sources. However, the inclusion of cross-field diffusion and shock smoothing from the backpressure of accelerated particles, effects likely to occur in astrophysical shocks, may significantly modify these predictions. C1 N CAROLINA STATE UNIV,DEPT PHYS,RALEIGH,NC 27695. RP BARING, MG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 24 TC 30 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 327 EP 332 DI 10.1086/172666 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800030 ER PT J AU MCCLEMENTS, KG BINGHAM, R SU, JJ DAWSON, JM SPICER, DS AF MCCLEMENTS, KG BINGHAM, R SU, JJ DAWSON, JM SPICER, DS TI LOWER HYBRID-RESONANCE ACCELERATION OF ELECTRONS AND IONS IN SOLAR-FLARES AND THE ASSOCIATED MICROWAVE EMISSION SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCELERATION OF PARTICLES; SUN, FLARES; SUN, PARTICLE EMISSION; SUN, RADIO RADIATION; SUN, X-RAYS, GAMMA-RAYS ID X-RAY BURSTS; STOCHASTIC ACCELERATION; RADIO SPIKES; INSTABILITIES; TURBULENT; SPECTRA; DISTRIBUTIONS; PRECIPITATION; SIMULATION; PARTICLES AB Nonlinear wave processes at the lower hybrid resonance frequency are extremely important in transferring energy between different particle populations and fields in both astrophysical and laboratory plasmas. In this paper we investigate particle acceleration resulting from the relaxation of unstable ion ring distributions, producing strong wave activity at the lower hybrid resonance frequency, which collapses to produce energetic electron and ion tails. We apply the results to the problem of explaining energetic particle production in solar flares. There are several mechanisms whereby unstable ion distributions could be formed in the solar atmosphere, including reflection at perpendicular shocks, tearing mode reconnection, and loss cone depletion. Numerical simulations of ion ring relaxation processes, obtained using a 2 1/2-dimensional fully electromagnetic, relativistic particle in cell code are presented. The results show the simultaneous acceleration of electrons to energies in the range 10-500 keV, and ions to energies of the order of 1 MeV. The electron flux is sufficiently high to account for flare hard X-ray emission, on the basis of the thick-target model. The MeV ions have insufficient energy to account for gamma-ray line emission in the 4-6 MeV range, but they provide a seed population for further acceleration, which could result from the presence of either lower hybrid or MHD wave turbulence. Particle energization is observed to occur inside elongated nonlinear wavepackets, indicating that the acceleration process is highly filamented. Our simulations also show wave generation at the electron cyclotron frequency. We suggest that this process could play a role in the production of solar millisecond radio spikes, which are normally attributed to the cyclotron maser instability. C1 NATL CENT UNIV,INST SPACE SCI,CHUNGLI,TAIWAN. RUTHERFORD APPLETON LAB,DIV ASTROPHYS,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. NASA,GODDARD SPACE FLIGHT CTR,CTR COMPUTAT SCI,GREENBELT,MD 20771. RP MCCLEMENTS, KG (reprint author), AEA FUS,CULHAM LAB,ABINGDON OX14 3DB,OXON,ENGLAND. NR 69 TC 44 Z9 44 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP 465 EP 475 DI 10.1086/172679 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB038 UT WOS:A1993LB03800043 ER PT J AU BRAATZ, JA WILSON, AS GEZARI, DY VAROSI, F BEICHMAN, CA AF BRAATZ, JA WILSON, AS GEZARI, DY VAROSI, F BEICHMAN, CA TI HIGH-RESOLUTION MIDINFRARED IMAGING AND ASTROMETRY OF THE NUCLEUS OF THE SEYFERT-GALAXY NGC-1068 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ASTROMETRY; GALAXIES, ACTIVE; GALAXIES, INDIVIDUAL (NGC 1068); GALAXIES, NUCLEI; GALAXIES, SEYFERT; INFRARED, GALAXIES ID IONIZING-RADIATION; ACTIVE GALAXIES; 10 MICRONS; NGC 1068; SPECTROPOLARIMETRY; GAS; POLARIZATION; KINEMATICS AB We have used the Goddard Infrared Array Camera to obtain a high resolution (0.7'' FWHM) image of the nucleus of NGC 1068 at 12.4 mum. The location of the 12.4 mum peak relative to the peak of the optical continuum has also been determined. The brightest part of the infrared nuclear peak is found to be elongated almost N-S (P.A. congruent-to 8-degrees), with an extent (corrected for instrumental blurring) congruent-to 0.6'' FWHM (45 pc). Fainter resolved structure in the deconvolved image extends congruent-to 2'' (150 pc) to the NE (P.A. congruent-to 30-degrees) and probably congruent-to 1.5'' (1 10 pc) to the SW (P.A. congruent-to 200-degrees). Approximately half of the nuclear 12.4 mum flux comes from this extended component. The distribution of 12.4 mum emission is correlated with both the [O III] lambda5007 ''ionization cone'' and the optical continuum emission imaged by HST, and it aligns perpendicular to the plane of a putative molecular torus. The morphology of the extended emission could be accounted for in terms of scattering of nuclear radiation by an extended electron cloud along the torus axis, but the observed polarization is both too low and in the wrong direction for this model. We suggest instead that the extended mid-infrared emission is thermal radiation from dust in circumnuclear clouds heated by the collimated optical/UV AGN source. Some or all of the unresolved 12.4 mum emission may still originate from the torus. The infrared emission peak is found to be 0.3'' (20 pc) +/- 0.15'' south of the optical continuum peak, and it coincides with the apex of the ionization cone, the presumed location of the torus. The observed displacement between the optical continuum and the mid-infrared peaks is similar to that predicted by Miller, Goodrich, & Mathews (1991) for the separation of the electron scattering zone from the nuclear optical/UV source. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV MARYLAND,DEPT MATH,COLL PK,MD 20742. HUGHES STX CORP,LANHAM,MD 20706. CALTECH,IPAC,PASADENA,CA 91125. RP BRAATZ, JA (reprint author), UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742, USA. NR 23 TC 60 Z9 60 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP L5 EP L8 DI 10.1086/186846 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB040 UT WOS:A1993LB04000002 ER PT J AU SNOWDEN, SL MCCAMMON, D VERTER, F AF SNOWDEN, SL MCCAMMON, D VERTER, F TI THE X-RAY SHADOW OF THE HIGH-LATITUDE MOLECULAR CLOUD MBM-12 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, CLOUDS; ISM, GENERAL; X-RAYS, INTERSTELLAR ID INTERSTELLAR-MEDIUM; SPECTRUM AB ROSAT XRT/PSPC observations show a deep shadow (I(on)/I(off) less than or similar to 0,3) cast by the high-latitude molecular cloud MBM 12 in the 3/4 keV diffuse background. Modeling of the shadow implies that <20% of the typical high-latitude 3/4 keV diffuse background intensity is emitted in front of the cloud (D = 60-70 pc). A weaker shadow consistent with the lower optical depth at higher energies was observed in the 1.5 keV band. Since little shadowing was seen in the 1/4 keV band, this observation places strong constraints on the amount of 0.5-2 keV emission that is intermixed with the source of the observed 1/4 keV flux. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SNOWDEN, SL (reprint author), UNIV WISCONSIN,DEPT PHYS,1150 UNIV AVE,MADISON,WI 53706, USA. RI Snowden, Steven/D-5292-2012 NR 37 TC 67 Z9 67 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1993 VL 409 IS 1 BP L21 EP L24 DI 10.1086/186850 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB040 UT WOS:A1993LB04000006 ER PT J AU NELSON, R HORNING, N AF NELSON, R HORNING, N TI FOREST NON-FOREST CLASSIFICATION OF MADAGASCAR FROM AVHRR DATA SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Editorial Material C1 STX CORP,LANHAM,MD 20706. RP NELSON, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Nelson, Ross/H-8266-2014 NR 1 TC 2 Z9 2 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 1993 VL 14 IS 8 BP 1445 EP 1446 PG 2 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA LM661 UT WOS:A1993LM66100001 ER PT J AU NELSON, R HORNING, N AF NELSON, R HORNING, N TI AVHRR-LAC ESTIMATES OF FOREST AREA IN MADAGASCAR, 1990 SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SATELLITE DATA; MSS DATA; VEGETATION; DEFORESTATION; IMAGES; BRAZIL AB Three AVHRR-LAC data sets acquired in September 1990 and January 1991 were used to map the forest resources of Madagascar. The island was partitioned into four strata to include: (1) the western hardwoods, (2) the central grasslands, (3) the eastern rainforest, and (4) spiny forest. Each stratum was classified separately using AVHRR-LAC data in conjunction with 1984-1988 Landsat-MSS photoproducts. The results of AVHRR classification indicate that approximately 11 per cent of the island is covered by forest. Approximately 1 per cent of the island was obscured by clouds and could not be enumerated. Estimates of forest area, by stratum, follow: western hardwoods, 6697 km2; central grasslands, 2830 km2; eastern rainforest 34167 km2; and spiny forest, 17 224 km2. The total forest area on the 587 041 km2 island is estimated to be 60918 km2. The AVHRR forest map was compared to a mid 1970s land cover map which was developed using Landsat-MSS photoproducts. The average class agreement between the mid 1970s ground reference map and the 1990 AVHRR-LAC map was 78.2 per cent, the overall accuracy was 81.1 per cent. Areas identified as forest on the ground reference map on the 1990 AVHRR map agreed only 62 per cent of the time, however, that figure confounds AVHRR misclassification error with actual forest loss over the decade. Much of the per-pixel disagreement between the ground reference and AVHRR maps involved areas identified as forest in the 1970s and as nonforest in 1990. These results demonstrate that one kilometre spatial resolution satellite data may be used to provide a reconnaissance level survey of the forest resources of a region or subcontinent when used in conjunction with fine resolution data. C1 STX CORP,LANHAM,MD 20706. RP NELSON, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Nelson, Ross/H-8266-2014 NR 37 TC 56 Z9 56 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 20 PY 1993 VL 14 IS 8 BP 1463 EP 1475 PG 13 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA LM661 UT WOS:A1993LM66100003 ER PT J AU WHITAKER, AF JANG, BZ AF WHITAKER, AF JANG, BZ TI THE MASS-LOSS MECHANISMS OF POLYMERS IN A RADIO-FREQUENCY INDUCED ATOMIC OXYGEN ENVIRONMENT SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article ID GLOW-DISCHARGE; PLASMA; FILMS AB The effects of atomic oxygen on several classes of polymers were investigated. Particular attention was directed to the determination of erosion or mass loss mechanisms in relation to the physical and chemical structures of polymers. Nineteen polymeric materials were exposed to a thermal atomic oxygen environment at fluxes of 10(22) atoms/m2-sec. Bulk material temperatures were maintained at 10, 45, and 75-degrees-C during exposure. Mass loss rate, which was characteristic of the type of polymer, was proportional to the exposure area and was linear in time for most polymers except for Mylar, which produced a shielding high temperature ash. The mass loss rate for the atomic oxygen degradation of polymers was related to the bond strength of the polymer structure and to the shielding effect of pendant structures. This degradation process was strongly dependent on polymer temperature. Activation energies ranged from 1 to 48 KJ/mole and were found to be related to gaseous diffusion in polymers. Frequency factors were proportional to activation energies. Activation energies were found to increase with increased mol wt and crosslinking. An equation was developed relating exposure area, atomic oxygen flux, frequency factor, and activation energy to the rate of polymer mass loss. C1 AUBURN UNIV,MAT ENGN PROGRAM,COMPOSITES RES LABS,201 ROSS HALL,AUBURN,AL 36849. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NR 47 TC 27 Z9 30 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD MAY 20 PY 1993 VL 48 IS 8 BP 1341 EP 1367 DI 10.1002/app.1993.070480804 PG 27 WC Polymer Science SC Polymer Science GA KZ347 UT WOS:A1993KZ34700004 ER PT J AU RUSSELL, PB PFISTER, L SELKIRK, HB AF RUSSELL, PB PFISTER, L SELKIRK, HB TI THE TROPICAL EXPERIMENT OF THE STRATOSPHERE-TROPOSPHERE EXCHANGE PROJECT (STEP) - SCIENCE OBJECTIVES, OPERATIONS, AND SUMMARY FINDINGS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC OZONE EXPERIMENT; AUSTRALIAN SUMMER MONSOON; AMEX PHASE-II; ER-2 AIRCRAFT; CONDENSATION NUCLEI; PARTICLE FORMATION; STRATIFORM REGION; CLOUD; TEMPERATURE; CIRCULATION AB The Stratosphere-Troposphere Exchange Project Tropical Experiment (STEP Tropical) investigated stratosphere-troposphere exchange and dehydration processes in that region and season with the coldest average tropopause temperatures, the tropical western Pacific and northern Australia during the winter monsoon (January-February) of 1987. This is also a period of extensive convective activity and rainfall. In addition to this primary goal, STEP Tropical (1) extended stratospheric aircraft chemical tracer surveys to the southern hemisphere subtropics and mid-latitudes and (2) sampled the anticyclone that dominates the circulation over Australia in the lower stratosphere during the winter monsoon. Advanced fast-response instruments on NASA's ER-2 aircraft measured meteorological variables, stratospheric and tropospheric tracers, particles, and radiative fluxes. ER-2 sorties included six ferry flight legs across the Pacific and eleven flights in the Australian region. The 1986-1987 monsoon was atypical in that (1) its date of onset, January 14, was 3 weeks later than normal and (2) it was unusually intense and sustained once it did arrive, As a consequence, almost all the flights were conducted under monsoon conditions, with only limited sampling of premonsoon and break-monsoon continental convection. Illustrations show flight paths for each sortie on satellite images and on 100 hPa synoptic flow charts, as well as the timing of flights with respect to overall cloudiness in the Australian region. STEP Tropical results, reported in the accompanying set of papers, include (1) observational documentation of a convective scale cold trap that dries air of recent tropospheric origin to prevailing stratospheric minimum water vapor mixing ratios (3 ppmv or less); (2) indications that this drying mechanism can be effective not only in the anvils of the tallest clouds (which occur during ''break-monsoon'' conditions) but also in the anvils of tropical cyclones and monsoon mesoscale convective systems; (3) demonstration that convectively generated gravity waves account for a significant part of the momentum forcing of the semiannual and quasi-biennial oscillations in the stratosphere; and (4) documentation of an upper tropospheric source of NOy and a significant upward flux of NOy at the tropical tropopause. For monsoon convection to be an important contributor to the net transfer of tropospheric air to the stratosphere, a mechanism is required to move air from the cloud tops to significantly greater heights. STEP Tropical results suggest that gravity-wave-induced small-scale turbulence or radiative heating of anvils provides this mechanism. Observational proof of the theoretically required high heating rates remains to be obtained. C1 SPACE PHYS RES INST,SUNNYVALE,CA 94087. RP RUSSELL, PB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Selkirk, Henry/H-2021-2012 NR 57 TC 46 Z9 46 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8563 EP 8589 DI 10.1029/92JD02521 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600002 ER PT J AU PFISTER, L CHAN, KR BUI, TP BOWEN, S LEGG, M GARY, B KELLY, K PROFFITT, M STARR, W AF PFISTER, L CHAN, KR BUI, TP BOWEN, S LEGG, M GARY, B KELLY, K PROFFITT, M STARR, W TI GRAVITY-WAVES GENERATED BY A TROPICAL CYCLONE DURING THE STEP TROPICAL FIELD PROGRAM - A CASE-STUDY SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ER-2 AIRCRAFT; SEMIANNUAL OSCILLATION; MIDDLE ATMOSPHERE; CIRCULATION MODEL; OZONE; ANVILS AB Overflights of a tropical cyclone during the Australian winter monsoon field experiment of the Stratosphere-Troposphere Exchange Project (STEP) show the presence of two mesoscale phenomena: a vertically propagating gravity wave with a horizontal wavelength of about 110 km and a feature with a horizontal scale comparable to that of the cyclone's entire cloud shield (wavelength of 250 km or greater). The larger feature is fairly steady, though its physical interpretation is ambiguous. The 110-km gravity wave is transient, having maximum amplitude early in the flight and decreasing in amplitude thereafter. Its scale is comparable to that of 100-to 150-km-diameter cells of low satellite brightness temperatures within the overall cyclone cloud shield: these cells have lifetimes of 4.5 to 6 hours. Aircraft flights through the anvil show that these cells correspond to regions of enhanced convection, higher cloud altitude, and upwardly displaced potential temperature surfaces. A three-dimensional transient linear gravity wave simulation shows that the temporal and spatial distribution of meteorological variables associated with the 110-km gravity wave can be simulated by a slowly moving transient forcing at the anvil top having an amplitude of 400-600 m, a lifetime of 4.5-6 hours and a size comparable to the cells of low brightness temperature. The forcing amplitudes indicate that the zonal drag due to breaking mesoscale transient convective gravity waves is definitely important to the westerly phase of the stratopause semiannual oscillation and possibly important to the easterly phase of the quasi-biennial oscillation. There is strong evidence that some of the mesoscale gravity waves break below 20 km as well. The effect of this wave breaking on the diabatic circulation below 20 km may be comparable to that of above-cloud diabatic cooling. C1 SAN JOSE STATE UNIV,SAN JOSE,CA 95192. JET PROP LAB,PASADENA,CA 91109. NOAA,AERON LAB,BOULDER,CO 80303. RP PFISTER, L (reprint author), NASA,AMES RES CTR,MAIL STOP 245-5,MOFFETT FIELD,CA 94035, USA. NR 27 TC 108 Z9 111 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8611 EP 8638 DI 10.1029/92JD01679 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600004 ER PT J AU DANIELSEN, EF AF DANIELSEN, EF TI INSITU EVIDENCE OF RAPID, VERTICAL, IRREVERSIBLE TRANSPORT OF LOWER TROPOSPHERIC AIR INTO THE LOWER TROPICAL STRATOSPHERE BY CONVECTIVE CLOUD TURRETS AND BY LARGER-SCALE UPWELLING IN TROPICAL CYCLONES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The STEP tropical objectives were successfully met during the flight experiments conducted from Darwin, Australia, January 16 to February 16, 1987. Necessary and sufficient measurements were made in, above, and downwind from very cold cirrus clouds, produced by three convective cloud types, to demonstrate irreversible mass transports into and dehydration in the lower tropical stratosphere. The three types are defined and described in terms of the physical processes that produce them and illustrated by examples derived from in situ and remote measurements. Intense solar heating is shown to produce, in addition to the usual vertical, sea breeze circulations normal to the coastline, an unusual pair of continental spanning, horizontal circulations. An upper tropospheric-lower stratospheric anticyclonic circulation, inclined upward toward the tropics, contributes to the dehydration of dissipating cirrus anvils and intensifies the upper level, tropical easterlies. The lower tropospheric cyclonic circulation with tropical westerlies and extratropical easterlies is in direct conflict with the normal tropical easterlies and extratropical westerlies. Impulsive switches between these two opposing lower-level wind systems create conditions favorable for each of these cloud types and explain the summer season's aperiodic variability. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 19 TC 183 Z9 184 U1 2 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8665 EP 8681 DI 10.1029/92JD02954 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600006 ER PT J AU WONG, T STEPHENS, GL STACKHOUSE, PW VALERO, FPJ AF WONG, T STEPHENS, GL STACKHOUSE, PW VALERO, FPJ TI THE RADIATIVE BUDGETS OF A TROPICAL MESOSCALE CONVECTIVE SYSTEM DURING THE EMEX-STEP-AMEX EXPERIMENT .1. OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MONSOON CLOUD CLUSTERS; SQUALL-LINE; AIR MOTIONS; PRECIPITATION; SATELLITE; DYNAMICS AB This paper is the first of a series of two that aim to describe the spatial and temporal variation of the radiative heating associated with tropical mesoscale convective systems (MCSs). This paper describes the analysis of data collected in and around a tropical cloud cluster system studied as part of the Equatorial Mesoscale Experiment (EMEX). The data analysis indicates that the cluster originated off the northern coast of Australia along the midlevel monsoon trough and lasted approximately 12 hours. The system moved with a velocity of about 12 m/s toward the northeast and the low-level surface northwesterly flow at the vicinity of the premonsoon trough area seems continuously to feed the EMEX 9 cloud cluster with energetic warm, moist equatorial air. Data obtained from aircraft penetrations show features similar to tropical MCSs reported elsewhere (such as an area of strong to moderate convection surrounded by a broad region of stratiform precipitation, radar echo bright band in the stratiform region, ''onion'' type sounding behind the convective region). The vertical structures of the EMEX 9 cloud cluster also contain two types of imbedded convection: an upright vertical structure and a pronounced rearward slope (approximately 17-degrees), having a vertical extent of 14.5 km and above and a horizontal scale of about 40 km. The cloud base and cloud top altitude in the stratiform region are estimated to be of the order of 4.8 km and 15 to 16 km, respectively. The composite aircraft shortwave radiation data from the stratiform region show a significant attenuation of shortwave flux through the cloud (the estimated transmission is 14% at cloud base). The upward and downward solar flux profiles are almost parallel to each other in the atmosphere inside and below the cloud base, suggesting very little solar heating in these regions. The upward and downward infrared radiation fluxes measured in the tropical MCS also show little infrared heating above and below the cloud cluster. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WONG, T (reprint author), COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523, USA. NR 33 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8683 EP 8693 DI 10.1029/92JD02515 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600007 ER PT J AU WONG, T STEPHENS, GL STACKHOUSE, PW VALERO, FPJ AF WONG, T STEPHENS, GL STACKHOUSE, PW VALERO, FPJ TI THE RADIATIVE BUDGETS OF A TROPICAL MESOSCALE CONVECTIVE SYSTEM DURING THE EMEX-STEP-AMEX EXPERIMENT .2. MODEL RESULTS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AVAILABLE POTENTIAL-ENERGY; SQUALL LINE; NUMERICAL-SIMULATION; WATER-VAPOR; CUMULUS CONVECTION; SOLAR-RADIATION; ABSORPTION; CIRRUS; CLOUDS; RATES AB This paper describes calculations of the spatial and temporal variation of the radiation budget of a tropical mesoscale convective system (MCS). A combination of cloud model simulations, radiation model simulations, and analyses of observations obtained during the Equatorial Mesoscale Experiment (EMEX), the Stratosphere-Troposphere Exchange Program (STEP), and the Australian Monsoon Experiment (AMEX) are used to obtain these heating rates. The two-dimensional version of the Colorado State University regional atmospheric modeling system is used to simulate a tropical MCS that occurred during EMEX mission 9 on February 2, 1987. The simulation is shown to broadly agree with the observations reported in a related paper. The spatial radiative heating distributions derived from a two-stream radiative transfer model corresponding to the mature stage of the simulated cloud system indicate that significant horizontal inhomogeneities exist. According to the model results the effects of the MCS are to (1) increase in the infrared emission to the surface and to decrease in the net infrared energy loss from the atmosphere relative to the clear sky emission and (2) change the transmission of solar flux to the surface, the shortwave albedo of the atmosphere, and the solar absorption in the atmosphere. The results show how the MCS significantly reduces the solar flux to the surface relative to the clear sky values and that the largest reduction occurs under the convective portions of the mature MCS. (3) The MCS creates a total (solar plus infrared) radiative warming in the atmosphere relative to the surrounding clear sky. The value of this total heating is governed by both infrared and solar absorption. Vertical profiles of this heating show the dominance of infrared cooling near cloud top and infrared heating inside and near cloud base. The shortwave heating rate can also be as large as the infrared cooling near the cloud top region of the tropical MCS, especially at a local noon. (4) The temporal changes in radiation profiles also demonstrate how the MCS modulates the radiation budget of the atmosphere. Specifically, the total radiation energy loss of the entire two-dimensional domain of the model atmosphere decreases and eventually becomes positive as the cloud system decays, becomes a stratiform in nature, and fills the domain. This change in the column divergence of flux translates into a total column radiative beating rate of approximately 1.7 K/d (relative to the clear sky radiative cooling rate). The solar component of this domain heating tends to be concentrated in the upper troposphere, whereas the infrared component of the heating is spread over the lower and middle troposphere. These results also show how tropical mesoscale cloud system provides an effective radiative heat source for the tropical atmosphere. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WONG, T (reprint author), COLORADO STATE UNIV,DEPT ATMOSPHER SCI,FT COLLINS,CO 80523, USA. NR 42 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8695 EP 8711 DI 10.1029/92JD02516 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600008 ER PT J AU KELLY, KK PROFFITT, MH CHAN, KR LOEWENSTEIN, M PODOLSKE Jr STRAHAN, SE WILSON, JC KLEY, D AF KELLY, KK PROFFITT, MH CHAN, KR LOEWENSTEIN, M PODOLSKE, JR STRAHAN, SE WILSON, JC KLEY, D TI WATER-VAPOR AND CLOUD WATER MEASUREMENTS OVER DARWIN DURING THE STEP 1987 TROPICAL MISSION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERE; SAMS; LIMS AB Measurements of stratospheric and upper tropospheric cloud water plus water vapor (total water) and water vapor were made with two Lyman a hygrometers as part of the STEP tropical experiment. The insitu measurements were made in the Darwin, Australia, area in January and February of 1987 on an ER-2 aircraft. Average stratospheric water vapor at a potential temperature of 375 K (the average value of theta at the tropopause) was 2.4 parts per million by volume (ppmv). This water mixing ratio is below the 3.0 to 4.0 ppmv necessary to be consistent with the observed upper stratospheric dryness. Saturation with respect to ice and the potential for dehydration was observed up to theta = 402 K. C1 PRINCETON UNIV, PRINCETON, NJ 08542 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST CHEM 2, W-5170 JULICH 1, GERMANY. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV DENVER, DENVER, CO 80208 USA. RP KELLY, KK (reprint author), NOAA, AERON LAB, BOULDER, CO 80303 USA. RI Strahan, Susan/H-1965-2012 NR 25 TC 66 Z9 66 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8713 EP 8723 DI 10.1029/92JD02526 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600009 ER PT J AU KRITZ, MA ROSNER, SW KELLY, KK LOEWENSTEIN, M CHAN, KR AF KRITZ, MA ROSNER, SW KELLY, KK LOEWENSTEIN, M CHAN, KR TI RADON MEASUREMENTS IN THE LOWER TROPICAL STRATOSPHERE - EVIDENCE FOR RAPID VERTICAL TRANSPORT AND DEHYDRATION OF TROPOSPHERIC AIR SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC RADON; RN-222; MECHANISM; PROFILES; PACIFIC; OCEAN AB During the tropical experiment of NASA's Stratosphere-Troposphere Exchange Program (STEP), in situ radon and other trace constituent measurements were made aboard a NASA ER-2 high-altitude research aircraft to investigate the mechanisms of irreversible transfers from the troposphere into the tropical stratosphere. Observations made in and downwind of the cirrus shields of three large tropical cyclones and downwind of the cirrus anvil of a large cumulonimbus cloud cluster showed several clear instances of elevated radon activity occurring simultaneously with low total water mixing ratios. These observations are unambiguous evidence of an effective dehydration process, capable of reducing total water vapor mixing ratios to less than 2.5 ppmv, occurring in conjunction with troposphere-to-stratosphere transport and indicate that rapid localized convection, rather than slow regional mean motions, was responsible for the observed transports and associated with the accompanying dehydration. Radon activities measured in regions of active or recent troposphere-to-stratosphere transport were consistent with the 17 pCi/scm mean value needed to support the observed abundance of stratospheric Pb-210. C1 NASA, AMES RES CTR, ATMOSPHER CHEM & DYNAM BRANCH, MOFFETT FIELD, CA 94035 USA. SUNY Albany, ATMOSPHER SCI RES CTR, ALBANY, NY 12222 USA. NOAA, AERON LAB, ENVIRONM RES LABS, BOULDER, CO 80303 USA. NR 51 TC 62 Z9 63 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8725 EP 8736 DI 10.1029/92JD02524 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600010 ER PT J AU PICKERING, KE THOMPSON, AM TAO, WK KUCSERA, TL AF PICKERING, KE THOMPSON, AM TAO, WK KUCSERA, TL TI UPPER TROPOSPHERIC OZONE PRODUCTION FOLLOWING MESOSCALE CONVECTION DURING STEP EMEX SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SQUALL LINE AB Aircraft data from the Stratosphere-Troposphere Exchange Project (STEP) and the Equatorial Mesoscale Experiment (EMEX) flights conducted on February 2, 1987, off northern Australia are used in cumulus cloud and photochemical models to determine the effects of convection on upper tropospheric O3 production. Ozone production is calculated as the amount integrated over cloud outflow layers for the first 24 hours after convection. Ozone production with convection is compared to ozone formation in undisturbed conditions. Model simulations of the EMEX 9 convective system indicate lower tropospheric air relatively rich in CO and low in NO(x) exiting in cloud outflow, slightly depressing the rate of O3 formation in the middle and upper troposphere. Other convective complexes, 800-900 km upstream, caused even greater perturbations to measured profiles of CO, NO(x), O3, and H2O and implied a 15-20% reduction in the rate of O3 production from 14.5 to 17 km. The greatest factor affecting O3 formation in the upper troposphere in the STEP/EMEX flight might have been lightning-produced NO(x). We estimate that O3 production from 12 to 17 km is 2-3 times more rapid than it would be with no lightning. This STEP/EMEX event adds to a climatology of half a dozen cases we have analyzed to determine the effects of convection on free tropospheric O3 production. The study region represents the ''maritime continent'' in contrast to continental regions studied previously. Relatively small quantities of species from the lower troposphere were transported to the upper troposphere because of the relatively weak vertical velocities in the storm and because chemical species gradients had been minimized by frequent convection prior to the February 2 event. Earlier in the convective season, the chemical consequences of a single episode might have been more substantial. C1 APPL RES CORP,LANDOVER,MD 20785. RP PICKERING, KE (reprint author), UNIV SPACE RES ASSOC,ATMOSPHERES LAB,NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 916,GREENBELT,MD 20771, USA. RI Pickering, Kenneth/E-6274-2012; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 30 TC 52 Z9 52 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8737 EP 8749 DI 10.1029/93JD00875 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600011 ER PT J AU MURPHY, DM FAHEY, DW PROFFITT, MH LIU, SC CHAN, KR EUBANK, CS KAWA, SR KELLY, KK AF MURPHY, DM FAHEY, DW PROFFITT, MH LIU, SC CHAN, KR EUBANK, CS KAWA, SR KELLY, KK TI REACTIVE NITROGEN AND ITS CORRELATION WITH OZONE IN THE LOWER STRATOSPHERE AND UPPER TROPOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID MOLECULE SPECTROSCOPY EXPERIMENT; WINTER POLAR STRATOSPHERES; CONTINENTAL UNITED-STATES; ACID AEROSOL FORMATION; NOX PRODUCTION-RATE; ODD-NITROGEN; NITRIC-ACID; ARCTIC STRATOSPHERE; INSITU MEASUREMENTS; ER-2 AIRCRAFT AB Reactive nitrogen (NO(y)) and O3 were measured simultaneously from a NASA ER-2 aircraft during 1987 through 1989. These high resolution measurements cover a broad range of latitudes in the upper troposphere and lower stratosphere. The data show a striking positive correlation between NO(y) and O3 in the lower stratosphere at all scales sampled. The ratio NO(y)/O3 is nearly independent of altitude from the tropopause to above 20 km, with ratios in the stratosphere of 0.0015-0.002 in the tropics and 0.0025-0.004 elsewhere. The ratio is much more constant than either individual species, thus providing an excellent reference point for comparing limited data sets with models. Two-dimensional models reproduce general features of the vertical profile of NO(y)/O3 but not the gradient in the lower stratosphere between tropics and mid-latitudes. NO(y) and O3 are better correlated in the lower stratosphere than in the upper troposphere. The magnitude and variability of both NO(y) mixing ratios and NO(y)/O3 ratios indicate a source of NO(y) in the upper troposphere. The most plausible source in the tropics is lightning production of NO(x). Condensation of NO(y) onto aerosol particles is often possible in the tropical upper troposphere and may play a role in determining the vertical distribution of NO(y). In the mid-latitude upper troposphere the data suggest long-range transport of NO(y). NO(y) mixing ratios in the tropical upper troposphere were usually between 150 and 600 pptv, enough so that upward transport can affect the NO(y) abundance in the tropical lower stratosphere. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV COLORADO,NOAA,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309. RP MURPHY, DM (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. RI Kawa, Stephan/E-9040-2012; Murphy, Daniel/J-4357-2012; Eubank, Charles/H-5585-2013; Fahey, David/G-4499-2013 OI Murphy, Daniel/0000-0002-8091-7235; Fahey, David/0000-0003-1720-0634 NR 111 TC 196 Z9 196 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8751 EP 8773 DI 10.1029/92JD00681 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600012 ER PT J AU CHEN, TC YEN, MC PFAENDTNER, J SUD, YC AF CHEN, TC YEN, MC PFAENDTNER, J SUD, YC TI THE VERTICAL STRUCTURE OF DIABATIC HEATING ASSOCIATED WITH THE MADDEN-JULIAN OSCILLATION SIMULATED BY THE GODDARD LABORATORY FOR ATMOSPHERES CLIMATE MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FREQUENCY INTRASEASONAL OSCILLATIONS; TROPICAL ATMOSPHERE; SCALE CIRCULATION; GCM SIMULATION; WAVE-CISK; PARAMETERIZATION; CONVECTION; ANOMALIES; RADIATION; BIOSPHERE AB Previous studies have shown that numerical simulations of the Madden-Julian oscillation (MJO) are very sensitive to the vertical distribution of diabatic heating. Since atmospheric diabatic heating is generally difficult to estimate, the vertical diabatic heating profile associated with the MJO is not well known. Judged by its propagation properties and spatial structure, the MJO is reasonably well simulated by the nine-layer Goddard Laboratory for Atmospheres (GLA) general circulation model. Although only a simulation the model MJO may provide an indication of the vertical diabatic heating profile associated with the real oscillation. The diabatic heating structure of the model MJO is illustrated with composite charts made for those times when this low-frequency mode reaches its maximum and minimum amplitudes. These composite charts compare the vertically integrated diabatic heating with potential functions, the vertical distribution of diabatic heating with the east-west mass flux function in the tropics, and the vertical profiles of diabatic heating at the centers of maximum and minimum MJO amplitude. Three interesting features of the model MJO's diabatic heating are revealed: (1) the maximum heating rate of this low-frequency mode is located over the Asian monsoon region and its amplitude is about a half of the maximum value of the seasonal mean heating rate in this region, (2) the vertical diabatic heating rate profile has a maximum at 500 mbar and resembles the seasonal mean total heating profile, and (3) the total diabatic heating is for the most part composed of the latent heat released by cumulus convection. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RP CHEN, TC (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT GEOL & ATMOSPHER SCI,ATMOSPHER SCI PROGRAM,3010 AGRON BLDG,AMES,IA 50011, USA. NR 32 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8801 EP 8813 DI 10.1029/93JD00342 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600016 ER PT J AU DOUGLASS, AR ROOD, RB WEAVER, CJ CERNIGLIA, MC BRUESKE, KF AF DOUGLASS, AR ROOD, RB WEAVER, CJ CERNIGLIA, MC BRUESKE, KF TI IMPLICATIONS OF 3-DIMENSIONAL TRACER STUDIES FOR 2-DIMENSIONAL ASSESSMENTS OF THE IMPACT OF SUPERSONIC AIRCRAFT ON STRATOSPHERIC OZONE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONSTITUENT TRANSPORT CALCULATIONS; MODEL; CONSERVATION; SCHEME; WAVES; MASS AB A two-dimensional (2D) model, which uses a residual circulation and diffusion, and a three-dimensional (3D) model, which uses winds from a stratospheric data assimilation system, have been used to estimate the transport and dispersion of aircraft exhaust (tracer) in the lower stratosphere. Four month calculations using the 2D model with tracer injected continuously between 40-degrees - 50-degrees north and south latitudes are compared with similar 3D calculations for the same time period. The seasonal behavior of the tracer fields in the two models is similar. The zonal mean of the 3D tracer distribution resembles the 2D distribution when the 2D calculation uses a residual circulation derived from the assimilated wind fields, but the 3D distribution indicates more rapid vertical mixing. The similarity of the 2D and 3D tracer distributions suggests the similarity of the seasonal mean mass transport in both models. However, there is a significant difference in the placement of stratosphere/troposphere exchange in the two models. In the 2D model, tracer transport to the troposphere takes place mostly at high latitudes. In the 3D model, most tracer transport takes place at middle latitudes, and is clearly associated with synoptic scale events. This may be particularly important to assessment calculations, as the pollutant source is mostly in middle latitudes. The 3D model is also used to consider the buildup of tracer in oceanic flight corridors. North Atlantic (Boston-London), north Pacific (Los Angeles - Tokyo) and tropical (Los Angeles-Sydney) corridors are considered. For northern hemisphere winter, the tracer distributions remain zonally asymmetric. The tracer from Boston-London is largely excluded from the Aleutian anti-cyclone, and the tracer from Los Angeles - Tokyo is largely contained within the anticyclone. The tropical tracer distribution is also asymmetric; the time scale for zonal mixing is long compared to the time for meridional transport processes due to weak zonal winds. Although more of the tracer injected in the tropical corridor is transported to higher altitude than for the other corridors, the transfer of mass from the stratosphere to the troposphere is nearly the same for the three corridors. There are no systematic differences that suggest that one corridor is inherently more or less polluting than another. C1 APPL RES CORP,LANDOVER,MD 20985. RES & DATA SYST,LANDOVER,MD. RP DOUGLASS, AR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,MAIL CODE 916,GREENBELT,MD 20771, USA. RI Douglass, Anne/D-4655-2012; Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 NR 35 TC 16 Z9 16 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8949 EP 8963 DI 10.1029/93JD00250 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600030 ER PT J AU HINES, ME PELLETIER, RE CRILL, PM AF HINES, ME PELLETIER, RE CRILL, PM TI EMISSIONS OF SULFUR GASES FROM MARINE AND FRESH-WATER WETLANDS OF THE FLORIDA EVERGLADES - RATES AND EXTRAPOLATION USING REMOTE-SENSING SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIOGENIC SULFUR; VEGETATION; CYCLE; MARSH; FLUX; DIMETHYLSULFIDE; VARIABILITY; ATMOSPHERE; SULFIDE; SOILS AB Rates of emissions of the biogenic sulfur (S) gases carbonyl sulfide (COS), methyl mercaptan (MSH). dimethyl sulfide (DMS), and carbon disulfide (CS2) were measured in a variety of marine and freshwater wetland habitats in the Florida Everglades during a short duration period in October using dynamic chambers, cryotrapping techniques, and gas chromatography. The most rapid emissions of >500 nmol m-2 h-1 occurred in red mangrove-dominated sites that were adjacent to open seawater and contained numerous crab burrows. Poorly drained red mangrove sites exhibited lower fluxes of approximately 60 nmol m-2 h-1 which were similar to fluxes from the black mangrove areas which dominated the marine-influenced wetland sites in the Everglades. DMS was the dominant organo-S gas emitted especially in the freshwater areas. Spectral data from a scene from the Landsat thematic mapper were used to map habitats in the Everglades. Six vegetation categories were delineated using geographical information system software and S gas emissions were extrapolated for the entire Everglades National Park. The black mangrove-dominated areas accounted for the largest portion of S gas emissions to the area. The large area extent of the saw grass communities (42%) accounted for approximately 24% of the total S emissions. C1 NASA,SCI & TECHNOL LAB,BAY ST LOUIS,MS. RP HINES, ME (reprint author), UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,MORSE HALL,DURHAM,NH 03824, USA. OI Crill, Patrick/0000-0003-1110-3059 NR 41 TC 18 Z9 18 U1 3 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1993 VL 98 IS D5 BP 8991 EP 8999 DI 10.1029/92JD03019 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD686 UT WOS:A1993LD68600033 ER PT J AU RODRIGUEZ, AM BOZZOLO, G FERRANTE, J AF RODRIGUEZ, AM BOZZOLO, G FERRANTE, J TI MULTILAYER RELAXATION AND SURFACE ENERGIES OF FCC AND BCC METALS USING EQUIVALENT CRYSTAL THEORY SO SURFACE SCIENCE LA English DT Review ID CUBIC TRANSITION-METALS; OXYGEN-COVERED NI(001); ION-SCATTERING; ELECTRON-DIFFRACTION; OSCILLATORY RELAXATION; LATTICE-RELAXATION; LEED ANALYSIS; AL(110) SURFACE; CU(110) SURFACE; SEMICONDUCTOR SURFACES AB The multilayer relaxation of fcc and bcc metal surfaces is calculated using equivalent crystal theory. The results for changes in interplanar spacings of planes close to the surface and the ensuing surface energies are discussed in reference to other theoretical results and compared to available experimental data. The calculation includes high-index surfaces for which no other theoretical results are known. C1 ANALEX CORP, BROOKPARK, OH 44142 USA. NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP RODRIGUEZ, AM (reprint author), NATL UNIV LA PLATA, DEPT FIS, CC 61, RA-1900 LA PLATA, ARGENTINA. NR 160 TC 113 Z9 115 U1 5 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD MAY 20 PY 1993 VL 289 IS 1-2 BP 100 EP 126 DI 10.1016/0039-6028(93)90891-M PG 27 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LE873 UT WOS:A1993LE87300020 ER PT J AU BOZZOLO, G GOOD, B FERRANTE, J AF BOZZOLO, G GOOD, B FERRANTE, J TI HEAT OF SEGREGATION OF SINGLE SUBSTITUTIONAL IMPURITIES SO SURFACE SCIENCE LA English DT Article ID AUGER-ELECTRON SPECTROSCOPY; PT-RH ALLOYS; EQUIVALENT-CRYSTAL THEORY; EMBEDDED-ATOM-METHOD; SURFACE-SEGREGATION; CU ALLOYS; PD ALLOYS; ENHANCED DIFFUSION; ION-BOMBARDMENT; SOLID-SOLUTIONS AB The method of Bozzolo, Ferrante and Smith (BFS) is applied for the calculation of the heat of segregation of single substitutional impurities in fcc metals. A simple equation for predicting the heat of segregation is derived for the rigid case (no atomic relaxations). The results of including atomic relaxation using a Monte Carlo method are also presented and the results compared with a number of experimental and theoretical results. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP BOZZOLO, G (reprint author), ANALEX CORP,3001 AEROSP PKWY,BROOKPARK,OH 44142, USA. NR 71 TC 23 Z9 23 U1 0 U2 3 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 20 PY 1993 VL 289 IS 1-2 BP 169 EP 179 DI 10.1016/0039-6028(93)90896-R PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA LE873 UT WOS:A1993LE87300025 ER PT J AU STECKL, AJ ROTH, MD POWELL, JA LARKIN, DJ AF STECKL, AJ ROTH, MD POWELL, JA LARKIN, DJ TI ATOMIC PROBE MICROSCOPY OF 3C SIC FILMS GROWN ON 6H SIC SUBSTRATES SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING TUNNELING MICROSCOPY; CHEMICAL VAPOR-DEPOSITION; 0001 6H-SIC WAFERS; EPITAXIAL-GROWTH; THIN-FILMS; SURFACES; SILICON AB The surface of 3C SiC films grown on 6H SiC substrates has been studied by atomic probe microscopy in air. Atomic-scale images of the 3C SiC surface have been obtained by scanning tunneling microscopy (STM). STM has confirmed the [111] orientation of the cubic 3C layer grown on the {0001} surface of the hexagonal 6H substrate. The nearest-neighbor atomic spacing for the 3C layer has been measured to be 3.29 +/- 0.2 angstrom, which is within 7% of the bulk value. Shallow terraces in the 3C layer have been observed by STM to separate regions of very smooth growth in the vicinity of the 3C nucleation point from considerably rougher 3C surface regions. These terraces are oriented at right angles to the growth direction. Atomic force microscopy has been used to study etch pits present on the 6H substrate due to high temperature HCI cleaning prior to chemical vapor deposition growth of the 3C layer. The etch pits have hexagonal symmetry and vary in depth from 50 nm to 1 mum. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP STECKL, AJ (reprint author), UNIV CINCINNATI,DEPT ELECT & COMP ENGN,NANOELECTR LAB,CINCINNATI,OH 45221, USA. OI Steckl, Andrew/0000-0002-1868-4442 NR 15 TC 15 Z9 15 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 17 PY 1993 VL 62 IS 20 BP 2545 EP 2547 DI 10.1063/1.109291 PG 3 WC Physics, Applied SC Physics GA LB885 UT WOS:A1993LB88500030 ER PT J AU WATANABE, WO ERNST, DH CHASAR, MP WICKLUND, RI OLLA, BL AF WATANABE, WO ERNST, DH CHASAR, MP WICKLUND, RI OLLA, BL TI THE EFFECTS OF TEMPERATURE AND SALINITY ON GROWTH AND FEED-UTILIZATION OF JUVENILE, SEX-REVERSED MALE FLORIDA RED TILAPIA CULTURED IN A RECIRCULATING SYSTEM SO AQUACULTURE LA English DT Article ID OREOCHROMIS-MOSSAMBICUS AB In two experiments, juvenile, sex-reversed male Florida red tilapia (avg. wt. = 0.56-1.20 g) were stocked into forty-two 0.33-m3 indoor tanks at a density of 74 fish m-3 and growth and feed utilization compared for 54-58 days at temperatures of 22, 27 and 32-degrees-C and at salinities of 0 and 18 ppt (experiment one) or at 18 and 36 ppt (experiment two) under a 12 L:12 D photoperiod. Fish were fed twice daily to satiation a 32% protein diet. Each treatment consisted of seven replicate tanks supported by a recirculating water system. While growth rates generally increased with increasing temperature and were markedly lower at 22-degrees-C than at 27 and 32-degrees-C, salinity modified the effects of temperature on growth: at 0 ppt, feed consumption and growth reached a maximum at 27-degrees-C, while at 18 and 36 ppt, consumption and growth were highest at 32-degrees-C. Under all temperatures, feed consumption and growth were higher at 18 ppt than at 0 or 36 ppt. The results suggested that, in freshwater, heating water to temperatures above 27-degrees-C is not justifiable, while at 18 or 36 ppt, heating water to 32-degrees-C can maximize growth rates without lowering growth efficiency. An important advantage of brackishwater (18 ppt) rearing under conditions of suboptimum temperatures was further suggested. C1 NATL MARINE FISHERIES SERV,HATFIELD MARINE SCI CTR,NW & ALASKA FISHERIES CTR,NEWPORT,OR. RP WATANABE, WO (reprint author), CARIBBEAN MARINE RES CTR,805 E 46TH PL,VERO BEACH,FL 32963, USA. NR 25 TC 31 Z9 37 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD MAY 15 PY 1993 VL 112 IS 4 BP 309 EP 320 DI 10.1016/0044-8486(93)90392-C PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA LG674 UT WOS:A1993LG67400003 ER PT J AU DOYLE, JF RIZZI, SA AF DOYLE, JF RIZZI, SA TI FREQUENCY-DOMAIN STRESS INTENSITY CALIBRATION OF DAMPED CRACKED PANELS SO INTERNATIONAL JOURNAL OF FRACTURE LA English DT Article AB This paper discusses two schemes for doing finite element K calibration in the frequency domain. The baseline scheme uses the definition of K as a limit toward the crack tip. The limiting process requires using a very fine mesh around the crack tip making the scheme computationally very expensive. It is shown that the behavior of K as a function of frequency is very similar to a modal response. Taking advantage of this, a more efficient scheme involves a modal analysis of the cracked sheet and scaling the response to that of the static stress intensity. In this way, only a static K calibration need be performed. All the examples shown are for a frequency range spanning multiple resonances and with two levels of damping. C1 NASA,LANGLEY RES CTR,STRUCT ACOUST BRANCH,HAMPTON,VA 23665. RP DOYLE, JF (reprint author), PURDUE UNIV,SCH AERONAUT & ASTRONAUT,W LAFAYETTE,IN 47906, USA. NR 10 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0376-9429 J9 INT J FRACTURE JI Int. J. Fract. PD MAY 15 PY 1993 VL 61 IS 2 BP 123 EP 130 DI 10.1007/BF00012452 PG 8 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA LM240 UT WOS:A1993LM24000002 ER PT J AU YAQOOB, T WARWICK, RS MAKINO, F OTANI, C SOKOLOSKI, JL BOND, IA YAMAUCHI, M AF YAQOOB, T WARWICK, RS MAKINO, F OTANI, C SOKOLOSKI, JL BOND, IA YAMAUCHI, M TI FURTHER PROBING OF THE X-RAY SOURCE IN NGC 4151 - NEW CONSTRAINTS ON THE NUCLEAR GEOMETRY SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ACCRETION; ACCRETION DISKS; GALAXIES; INDIVIDUAL; NGC 4151; GALAXIES; NUCLEI; GALAXIES; SEYFERT; X-RAYS; GALAXIES ID NARROW-LINE REGION; SEYFERT-GALAXIES; COLD MATTER; NGC-4151; REFLECTION; SPECTRUM; EMISSION; ABSORPTION; FEATURES; VARIABILITY AB We report on the results of new Ginga observations of the archetypal Seyfert galaxy, NGC 4151, performed over an 18-month period between early 1990 and mid-1991. The present programme complements earlier extensive monitoring of this source in the medium-energy X-ray band by both EXOSAT and Ginga to give a combined data set of some 36 separate observations made over a period of eight years. The most interesting aspect of the new observations is that they bring to light a remarkable transient change in the low-energy extinction and soft X-ray excess apparent in the X-ray spectrum of NGC 4151. The spectrum became systematically softer below approximately 4 keV from mid-1988, with the spectral softness peaking in mid-1990 and then reverting to its former state by late 1990. Interpreting this in terms of the partial covering model, the covered fraction of the source, which normally takes a value of 80-90 per cent, underwent a sharp decline to approximately 20 per cent over a two-year period and then returned to the canonical level over the following six months. This observation would seem to rule out a cloud model for the X-ray absorbing medium in NGC 4151 and favour the presence of a normally stable 'bulk' structure such as an edge-on accretion disc. A transitory change of azimuthal structure in the disc could then account for the apparent dip in the covered fraction. If the central X-ray source radiates isotropically then the medium producing the bulk of the iron-line emission must deviate from a spherically symmetric distribution in such a way that its column density in most directions is at least 6 x 10(22) cm-2 but less than or similar to 10(22) cm-2 in our line of sight. However, a more reasonable model may be one in which there is substantial anisotropic X-ray illumination of broad-line clouds out of our direct line of sight, in which case the true X-ray luminosity of NGC 4151 may be much higher than is generally assumed. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. UNIV LEICESTER,DEPT PHYS & ASTRON,LEICESTER LE1 7RH,ENGLAND. INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. RI Otani, Chiko/A-6510-2016 NR 30 TC 83 Z9 83 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 15 PY 1993 VL 262 IS 2 BP 435 EP 448 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC064 UT WOS:A1993LC06400020 ER PT J AU ZHOU, SM HE, QB YEH, PC LIU, HK AF ZHOU, SM HE, QB YEH, PC LIU, HK TI SPATIAL FIDELITY IN PHOTOREFRACTIVE IMAGE AMPLIFICATION SO OPTICS COMMUNICATIONS LA English DT Article ID CRYSTALS AB The spatial fidelity of amplified images in photorefractive materials due to spatial pin variations with computation and experiment based on BaTiO3 is investigated. The results will indicate how the spatial fidelity of the amplified images decreases as the relative aperture of the Fourier transform lens used in the system increases, and varies with the angle between the pump beam and the axis of the signal converging wave. C1 JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. ROCKWELL INT CORP,CTR SCI,THOUSAND OAKS,CA 91360. RP ZHOU, SM (reprint author), UNIV CALIF SANTA BARBARA,DEPT ELECT & COMP ENGN,SANTA BARBARA,CA 93106, USA. RI Yeh, Pochi/A-2109-2010 NR 7 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD MAY 15 PY 1993 VL 99 IS 1-2 BP 18 EP 24 DI 10.1016/0030-4018(93)90698-5 PG 7 WC Optics SC Optics GA LA352 UT WOS:A1993LA35200004 ER PT J AU BAE, K NELSON, HG AF BAE, K NELSON, HG TI EFFECTS OF R-RATIO ON FATIGUE CRACK-GROWTH IN A TI-24AL-11NB ALLOY SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID TI65AL25NB10 ALLOY C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BAE, K (reprint author), UNIV SUWON,DEPT ELECT MAT,SUWON 445743,SOUTH KOREA. NR 15 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAY 15 PY 1993 VL 28 IS 10 BP 1267 EP 1272 DI 10.1016/0956-716X(93)90466-6 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA KW621 UT WOS:A1993KW62100018 ER PT J AU SODUPE, M BAUSCHLICHER, CW AF SODUPE, M BAUSCHLICHER, CW TI THE BONDING IN FEC5H5(+) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GAS-PHASE; PHOTODISSOCIATION; ORBITALS; ENERGY; ATOMS AB The computed binding energy of 77 +/- 10 kcal/mol for the 2E2 state of Fe+-C5H5 is in reasonable agreement with the experimental value of 88 +/- 7 kcal/mol. The Fe+ binding energy for C5H5 is much larger than that found for C6H6, as found in experiment. While the electrostatic bonding in FeC6H6+ is enhanced by Fe to ligand pi* donation, the electrostatic bonding in FeC5H5+ is enhanced by the formation of a bond between the open-shell pi orbital on C5H5 and Fe+. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 14 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 14 PY 1993 VL 207 IS 1 BP 19 EP 22 DI 10.1016/0009-2614(93)85004-8 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LB949 UT WOS:A1993LB94900004 ER PT J AU OHSAKA, K TRINH, EH HOLZER, JC JOHNSON, WL AF OHSAKA, K TRINH, EH HOLZER, JC JOHNSON, WL TI GIBBS FREE-ENERGY DIFFERENCE BETWEEN THE GLASS AND CRYSTALLINE PHASES OF A NI-ZR ALLOY SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSITION AB The heats of eutectic melting and devitrification, and the specific heats of the crystalline, glass, and liquid phases have been measured for a Ni24Zr76 alloy. The data are used to calculate the Gibbs free-energy difference, DELTAG(AC), between the real glass and the crystal on an assumption that the liquid-glass transition is second order. The result shows that DELTAG(AC) continuously increases as the temperature decreases in contrast to the ideal glass case where DELTAG(AC) is assumed to be independent of temperature. C1 CALTECH,WM KECK LAB ENGN MAT,PASADENA,CA 91125. RP OHSAKA, K (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 12 TC 17 Z9 17 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 10 PY 1993 VL 62 IS 19 BP 2319 EP 2321 DI 10.1063/1.109404 PG 3 WC Physics, Applied SC Physics GA LA797 UT WOS:A1993LA79700007 ER PT J AU LANGER, WD PENZIAS, AA AF LANGER, WD PENZIAS, AA TI C-12/C-13 ISOTOPE RATIO IN THE LOCAL INTERSTELLAR-MEDIUM FROM OBSERVATIONS OF (CO)-C-13-O-18 IN MOLECULAR CLOUDS SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, ABUNDANCES; ISM, CLOUDS; ISM, MOLECULES ID STELLAR DARK CLOUDS; CARBON-MONOXIDE; ZETA-OPHIUCHI; ORION-A; FRACTIONATION; CORE; ABUNDANCES; BARNARD-5; AMMONIA; GALAXY AB The C-12/C-13 isotope ratio is studied in the solar neighborhood from observations of the (CO)-C-12-O-18 and (CO)-C-13-O-18 J = 1-0 transitions in four interstellar clouds located within 500 pc. Three of these, B5, B335, and L183 (L134N), are dark clouds not associated with strong H II regions, and the fourth is at a position in Orion A relatively distant from the H II region associated with the KL source. The C-12/C-13 ratio in these sources (after corrections for a small amount of radiative trapping) ranges from 57 to 74, and its weighted average is 62 +/- 4, with thermal noise and line formation uncertainties contributing about equally to the probable error. This ratio is consistent with the value we previously derived from the (CO)-C-12-O-18/(CO)-C-13-O-18 Galactic gradient, as well as with the most likely range, 60-70, determined from CH+ absorption measurements in the diffuse cloud zeta Oph. Thus the most reliable CO and CH+ results are consistent within their errors. The resulting value indicates moderate chemical evolution in the local solar neighborhood since the formation of the solar system, in good agreement with model prediction of the current carbon ratio in the local interstellar medium. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. RP LANGER, WD (reprint author), JET PROP LAB,MS 169-506,PASADENA,CA 91109, USA. NR 50 TC 146 Z9 146 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP 539 EP 547 DI 10.1086/172611 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA024 UT WOS:A1993LA02400016 ER PT J AU THOMAS, B CORBET, R AUGUSTEIJN, T CALLANAN, P SMALE, AP AF THOMAS, B CORBET, R AUGUSTEIJN, T CALLANAN, P SMALE, AP TI OPTICAL AND X-RAY OBSERVATIONS OF THE LOW-MASS X-RAY BINARY EXO 0748-676 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; STARS, INDIVIDUAL (EXO 0748-676); X-RAYS, STARS AB Optical and X-ray observations of EXO-676 in late March 1989 are presented. Our optical observations provide some support for the previously observed correlation between the mean optical brightness and light curve morphology. Unexpectedly, the mean X-ray and optical flux levels during this period do not reflect similar system states. The optical counterpart is found to be in an intermediate to low state (V(PHI = 0.5) = 17.18 +/- 0.02) while X-ray data imply a bright (high) state. The changed relationship between optical and X-ray fluxes is evidence showing that EXO 0748-676 has possibly evolved. We fail to find correlated variability in simultaneous X-ray and optical observations. The lack of covariability is attributed to the limited simultaneous coverage of the source and/or significant geometric modulation in the optical light curve. C1 UNIV AMSTERDAM,ASTRON INST ANTON PANNEKOEK,1098 SJ AMSTERDAM,NETHERLANDS. CTR HIGH ENERGY ASTROPHYS,1098 SJ AMSTERDAM,NETHERLANDS. CTR ASTROPHYS,CAMBRIDGE,MA 02138. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP THOMAS, B (reprint author), PENN STATE UNIV,DAVEY LAB 5251,DEPT ASTRON & ASTROPHYS,UNIV PK,PA 16802, USA. NR 21 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP 651 EP 655 DI 10.1086/172624 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA024 UT WOS:A1993LA02400029 ER PT J AU DAY, CSR NAGASE, F ASAI, K TAKESHIMA, T AF DAY, CSR NAGASE, F ASAI, K TAKESHIMA, T TI THE DISCOVERY OF PULSED IRON LINE EMISSION FROM CENTAURUS X-3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, ECLIPSING; PULSARS, INDIVIDUAL (CENTAURUS X-3); STARS, INDIVIDUAL (CENTAURUS X-3); X-RAYS, STARS ID X-RAY BINARIES; TENMA OBSERVATIONS; GINGA; GX301-2; PULSARS AB We present the first discovery of pulsed iron line emission from an X-ray binary, namely Cen X-3. Compared with the continuum pulsations, the iron line pulsations are shallow (50% change in amplitude), smeared (the profile is a single-peaked sinusoid) and phase-shifted (by about half a cycle). We also discuss the constraints on the origin of the line imposed by this discovery and by other observations. C1 INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. RP DAY, CSR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 668,GREENBELT,MD 20771, USA. NR 20 TC 17 Z9 17 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP 656 EP 659 DI 10.1086/172625 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA024 UT WOS:A1993LA02400030 ER PT J AU BHATIA, AK KASTNER, SO AF BHATIA, AK KASTNER, SO TI THE OPTICALLY THIN C-III SPECTRUM - LINE AND MULTIPLET INTENSITIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; STARS, WOLF-RAYET ID ELECTRON-IMPACT-EXCITATION; IONS AB C III line/multiplet intensities expected under optically thin conditions are presented over the density/temperature ranges 4.0 less-than-or-equal-to log N(e) less-than-or-equal-to 12.0, 4.6 less-than-or-equal-to log T(e) less-than-or-equal-to 5.0 (40,000 less-than-or-equal-to T(e) less-than-or-equal-to 100,000 K). These improved values are obtained from a hybrid level/term calculation which makes use of the most recently available atomic data and extends the treatment down to lower densities than were achieved with our previous term representation. Some illustrative applications are given, including a brief description of the importance of the present data for interpretation of the strong C III line emission from carbon Wolf-Rayet stars. C1 MATH SCI CONSULTANTS INC,GREENBELT,MD 20770. RP BHATIA, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 18 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP 744 EP 752 DI 10.1086/172634 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA024 UT WOS:A1993LA02400039 ER PT J AU MURTHY, J DRING, A HENRY, RC KRUK, JW BLAIR, WP KIMBLE, RA DURRANCE, ST AF MURTHY, J DRING, A HENRY, RC KRUK, JW BLAIR, WP KIMBLE, RA DURRANCE, ST TI HOPKINS ULTRAVIOLET TELESCOPE OBSERVATIONS OF FAR-ULTRAVIOLET SCATTERING IN NGC-7023 - THE DUST ALBEDO SO ASTROPHYSICAL JOURNAL LA English DT Article DE DUST, EXTINCTION; ISM, INDIVIDUAL OBJECTS (NGC-7023); REFLECTION NEBULAE; ULTRAVIOLET, STARS ID OPTICAL-PROPERTIES; INTERSTELLAR DUST; EXTINCTION AB We have obtained the first sub-Lyalpha spectroscopic observations of the reflection nebula NGC 7023 and its illuminating star, HD 200775, using the Hopkins Ultraviolet Telescope during the Astro-1 mission in 1990 December. The ratio of the nebular to stellar flux is virtually flat between 1100 and 1860 angstrom, indicating that sigma(a), the cross section for absorption, must rise sharply with decreasing wavelength. Independent of any model, this means that much of the far-ultraviolet rise in the extinction curve is due to an increase in absorption rather than scattering. If, in addition, we assume a spherical geometry, we derive an albedo of 0.5 at 1100 angstrom with somewhat higher values at longer wavelengths. If the geometry is not spherical, lower values of the albedo may be obtained. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 681,GREENBELT,MD 20771. RP MURTHY, J (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. RI Murthy, Jayant/F-4433-2010; Kruk, Jeffrey/G-4047-2012; OI Murthy, Jayant/0000-0003-4034-5137 NR 16 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP L97 EP L100 DI 10.1086/186840 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA025 UT WOS:A1993LA02500007 ER PT J AU STOTHERS, RB CHIN, CW AF STOTHERS, RB CHIN, CW TI DYNAMIC INSTABILITY AS THE CAUSE OF THE MASSIVE OUTBURSTS IN ETA-CARINAE AND OTHER LUMINOUS BLUE VARIABLES SO ASTROPHYSICAL JOURNAL LA English DT Article DE CONVECTION; STARS, EVOLUTION; STARS, INDIVIDUAL (ETA-CARINAE); STARS, OSCILLATIONS; STARS, VARIABLES, OTHER MISCELLANEOUS ID S-DORADUS VARIABLES; EVOLUTION; NEBULA; STARS AB A new type of stellar envelope structure has been computationally discovered at very high stellar masses. The outer part of the envelope resembles a nearly detached, diffusely filled shell overlying an ultrahot surface of small radius. This structural anomaly is caused by a large iron bump occurring in the new opacities of Iglesias, Rogers, and Wilson. The new stellar models with normal metallicity encounter a strong ionization-induced dynamical instability in the outer envelope as they rapidly transit the H-R diagram after the end of central hydrogen burning. Preliminary evolutionary and hydrodynamical calculations successfully mimic the most basic observed properties of eta Carinae and other very luminous blue variables. The Humphreys-Davidson sloped line in the H-R diagram, however, seems to be unrelated to these variables, but is rather the observed terminus of the main-sequence phase of evolution if convective core overshooting is insignificant. RP STOTHERS, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 32 TC 63 Z9 63 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1993 VL 408 IS 2 BP L85 EP L88 DI 10.1086/186837 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA025 UT WOS:A1993LA02500004 ER PT J AU HERGENROTHER, PM JENSEN, BJ HAVENS, SJ AF HERGENROTHER, PM JENSEN, BJ HAVENS, SJ TI NEW POLYMERIZATION METHODOLOGY - SYNTHESIS OF THIOPHENE-BASED HETEROCYCLIC POLYETHERS (VOL 25, PG 4235, 1992) SO MACROMOLECULES LA English DT Correction, Addition C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. RP HERGENROTHER, PM (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 2 TC 2 Z9 2 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 10 PY 1993 VL 26 IS 10 BP 2641 EP 2641 DI 10.1021/ma00062a041 PG 1 WC Polymer Science SC Polymer Science GA LC778 UT WOS:A1993LC77800041 ER PT J AU DYALL, KG PARTRIDGE, H AF DYALL, KG PARTRIDGE, H TI RELATIVISTIC CORRECTIONS TO THE PROPERTIES OF THE ALKALI FLUORIDES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BASIS SET CALCULATIONS; ALGEBRAIC-APPROXIMATION; HYDROGENIC ATOMS; DIRAC-EQUATION; ENERGIES AB Relativistic corrections to the bond lengths, dissociation energies and harmonic frequencies of KF, RbF and CsF have been obtained at the self-consistent field level by dissociating to ions. The relativistic corrections to the bond lengths, harmonic frequencies and dissociation energies to the ions are very small, due to the ionic nature of these molecules and the similarity of the relativistic and nonrelativistic ionic radii. C1 ELORET INST,PALO ALTO,CA 94303. RP DYALL, KG (reprint author), NASA,AMES RES CTR,MS RTC 230-3,MOFFETT FIELD,CA 94035, USA. NR 21 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 7 PY 1993 VL 206 IS 5-6 BP 565 EP 567 DI 10.1016/0009-2614(93)80184-Q PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA LA326 UT WOS:A1993LA32600024 ER PT J AU CAMPBELL, BA GARVIN, JB AF CAMPBELL, BA GARVIN, JB TI LAVA FLOW TOPOGRAPHIC MEASUREMENTS FOR RADAR DATA INTERPRETATION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SCATTERING AB Surface topography is of great importance in radar backscattering, but the quantitative interpretation of data collected in the field is still a difficult problem. We present topographic profiles at 25-cm and 5-cm horizontal resolution for three sites along a lava flow on Kilauea Volcano, and use these data to illustrate techniques for surface roughness analysis. Height and slope distributions and the height autocorrelation function are evaluated as a function of varying lowpass filter wavelength for the 25-cm data. Rms slopes are found to increase rapidly with decreasing topographic scale and are typically much higher than those found by modeling of Magellan altimeter data for Venus. A more robust description of the surface roughness appears to be the ratio of rms height to surface height correlation length. For all three sites this parameter falls within the range of values typically found from model fits to Magellan altimeter waveforms. The 5-cm profile data are used to estimate the effect of small-scale roughness on quasi-specular scattering. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP CAMPBELL, BA (reprint author), NATL AIR & SPACE MUSEUM,CTR EARTH & PLANETARY STUDIES,WASHINGTON,DC 20560, USA. NR 13 TC 17 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 7 PY 1993 VL 20 IS 9 BP 831 EP 834 DI 10.1029/93GL00737 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LC958 UT WOS:A1993LC95800017 ER PT J AU TIEMANN, BG CHENG, LT MARDER, SR AF TIEMANN, BG CHENG, LT MARDER, SR TI THE EFFECT OF VARYING GROUND-STATE AROMATICITY ON THE 1ST MOLECULAR ELECTRONIC HYPERPOLARIZABILITES OF ORGANIC DONOR-ACCEPTOR MOLECULES SO JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS LA English DT Article ID OPTICAL SUSCEPTIBILITIES AB A series of compounds of the form 4-dimethylaminophenyl-polyene-acceptor, where the polyene ranges from nothing to all-trans-1,3,5-hexatriene and the acceptor is 2-nitrovinyl, formyl, or 2,2-dicyanovinyl has been prepared and their beta values measured by solution electric-field-induced second-harmonic generation; these molecules, which lose only one aromatic resonance upon charge-transfer excitation, show enhanced beta compared to bi-aromatic molecules with the same substitution and total conjugation length, such as 4-dimethylamino-4'-nitrostilbene (DANS), a well-known benchmark for high beta organic molecules. C1 DUPONT CO INC,DEPT CENT RES & DEV,WILMINGTON,DE 19880. JET PROP LAB,PASADENA,CA 91109. CALTECH,BECKMAN INST,CTR MOLEC MAT RESOURCE,PASADENA,CA 91125. NR 12 TC 36 Z9 36 U1 0 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0022-4936 J9 J CHEM SOC CHEM COMM JI J. Chem. Soc.-Chem. Commun. PD MAY 7 PY 1993 IS 9 BP 735 EP 737 DI 10.1039/c39930000735 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA LC022 UT WOS:A1993LC02200009 ER PT J AU MACINNES, AN POWER, MB HEPP, AF BARRON, AR AF MACINNES, AN POWER, MB HEPP, AF BARRON, AR TI INDIUM TERT-BUTYLTHIOLATES AS SINGLE-SOURCE PRECURSORS FOR INDIUM SULFIDE THIN-FILMS - IS MOLECULAR DESIGN ENOUGH SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; TIN-OXIDE-FILMS AB The dimeric indium thiolates [R2In(mu-StBu)]2 R = (t)Bu (1), (n)Bu (2), Me (3), and [((t)BuS)MeIn(mu-StBu)]2 (4) have been synthesized and used as single source precursors for the metal-organic chemical vapor deposition (MOCVD) of In/InS and InS thin films. In the case of the atmospheric pressure film grown from either 1 or 2, deposition at temperatures between 290 and 350-degrees-C results in the formation of indium rich films (In: S approximately 2) consisting of indium metal and orthorhombic InS, while at 400-degrees-C a single phase; the tetragonal high pressure phase of InS, is the only product deposited. Use of compound 3 as the precursor results in amorphous indium rich films being deposited at 300-degrees-C. While films grown from 3 at 400-degrees-C have a In: S ratio of 1, they consist of an indium rich phase and In2S3. The dependence of the film composition i.e., indium rich versus stoichiometric InS and structure (orthorhombic versus tetragonal InS) with the deposition temperature and molecular precursor is discussed with respect to the decomposition pathways available to the precursor molecules (1-3). Based on these results compound 4 was proposed to be a suitable precursor for the low temperature deposition of stoichiometric InS, indeed its solid state pyrolysis does yield InS. However, although low pressure MOCVD using 4 yields amorphous films of stoichiometry InS, upon annealing beta-In2S3 is formed as the crystalline phase. The efficacy of molecular design of solid state materials is discussed. The indium thiolates were characterized by H-1 and C-13 NMR spectroscopy and mass spectrometry. Analysis of the deposited films has been obtained by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), with associated energy dispersive X-ray analysis (EDX). C1 HARVARD UNIV,DEPT CHEM,CAMBRIDGE,MA 02138. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. OI Barron, Andrew/0000-0002-2018-8288 NR 40 TC 43 Z9 43 U1 1 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD MAY 4 PY 1993 VL 449 IS 1-2 BP 95 EP 104 DI 10.1016/0022-328X(93)80111-N PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA LD055 UT WOS:A1993LD05500012 ER PT J AU COHEN, DM ROHR, BA AF COHEN, DM ROHR, BA TI DESCRIPTION OF A GIANT CIRCUMGLOBAL LAMPROGRAMMUS SPECIES (PISCES, OPHIDIIDAE) SO COPEIA LA English DT Article AB A new giant (nearly 2 m long) ophidiid fish species, Lamprogrammus shcherbachevi, is described from specimens caught at bathyal depths in the equatorial eastern and western Atlantic, the southeastern Indian, and the southeastern Pacific oceans. It is characterized by its elongate body and distinctive series of spines on the preopercle and opercle. C1 NATL MARINE FISHERIES SERV,PASCAGOULA,MS 39567. RP COHEN, DM (reprint author), LOS ANGELES CTY MUSEUM NAT HIST,900 EXPOSIT BLVD,LOS ANGELES,CA 90007, USA. NR 9 TC 3 Z9 4 U1 1 U2 1 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 SN 0045-8511 J9 COPEIA JI Copeia PD MAY 3 PY 1993 IS 2 BP 470 EP 475 PG 6 WC Zoology SC Zoology GA LA729 UT WOS:A1993LA72900020 ER PT J AU HOPSON, GD GRANT, RL AF HOPSON, GD GRANT, RL TI VERIFICATION OF SPACE STATION FREEDOM ELEMENTS AND SYSTEMS SO ACTA ASTRONAUTICA LA English DT Article AB Space Station Freedom is composed of many distributed systems and elements being designed, built and tested at various work centers and international locations. The station will be assembed on orbit over a period of time greater than 4 years with the station conducting research and experimentation throughout the assembly process. Because of this extended time period of assembly and limited available resources, it is impractical to perform an integrated ground test of the complete orbital assembly. Accordingly, the Space Station Freedom Program verification program offers a unique challenge not experienced in other programs. The Space Station Freedom verification program includes development, qualification, acceptance and prelaunch phases to ensure that the station will meet the design and operational requirements prior to launch. This verification program places emphasis on verifying on the ground the physical and functional compatibility of interfaces for the different elements and launch packages prior to their being mated on orbit. RP HOPSON, GD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,KA01,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY PY 1993 VL 29 IS 5 BP 399 EP 406 DI 10.1016/0094-5765(93)90023-P PG 8 WC Engineering, Aerospace SC Engineering GA LD358 UT WOS:A1993LD35800008 ER PT J AU KUMAR, KS DIPIETRO, MS WHITTENBERGER, JD AF KUMAR, KS DIPIETRO, MS WHITTENBERGER, JD TI COMPRESSION RESPONSE OF MONOLITHIC AND PARTICULATE-REINFORCED COMPOSITES OF AL67TI25CR8 AND AL66TI25MN9 SO ACTA METALLURGICA ET MATERIALIA LA English DT Article ID CUBIC PHASES; TEMPERATURE; DEFORMATION; BEHAVIOR; AL3TI AB The compression behavior of powder-metallurgy (P/M) processed monolithic L1(2) compounds Al66Ti23Mn9, Al67Ti25Cr8 and their 20 vol. % TiB2 particulate-containing counterparts were evaluated as a function of temperature and, at high temperatures (1000 and 1100 K), as a function of strain rate. Hot-pressed and deformed microstructures were examined by optical and transmission electron microscopy. Variations in strength with temperature and with strain rate at 1000 K of the P/M-processed monolithic materials from this study are compared against previous data for similar materials obtained by ingot metallurgy processing. Observed differences are attributed predominantly to grain size effects. For the composites, stress exponents and activation energies for creep were obtained using the power law creep equations which adequately describe the data. Compression studies were conducted between room temperature and approximately 800 K on specimens of the composite material that had been subjected to various intermediate temperature heat treatments in an effort to understand qualitatively the extent to which the intrinsic matrix composition, solid solution component and precipitation strengthening (by Al2Ti), each contributes to the observed compressive yield strength-temperature profiles. C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP KUMAR, KS (reprint author), MARTIN MARIETTA CORP LABS, BALTIMORE, MD 21227 USA. NR 16 TC 11 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-7151 J9 ACTA METALL MATER JI Acta Metall. Mater. PD MAY PY 1993 VL 41 IS 5 BP 1379 EP 1389 DI 10.1016/0956-7151(93)90247-P PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA LA003 UT WOS:A1993LA00300006 ER PT J AU MENENTI, M AF MENENTI, M TI UNDERSTANDING LAND SURFACE EVAPOTRANSPIRATION WITH SATELLITE MULTISPECTRAL MEASUREMENTS SO ADVANCES IN SPACE RESEARCH LA English DT Article ID ENERGY BALANCE; METEOROLOGICAL DATA; CANOPY TEMPERATURE; HEAT-FLUX; EVAPORATION; MODEL; WATER; RADIATION AB Quantitative use of remote multispectral measurements to study and map land surface evapotranspiration has been a challenging issue for the past 20 years. Past work is reviewed against process physics. A simple two-layer combination-type model is used which is applicable to both vegetation and bare soil. The theoretic analysis is done to show which land surface properties are implicitly defined by such evaporation models and to assess whether they are measurable as a matter of principle. Conceptual implications of the spatial correlation of land surface properties, as observed by means of remote multispectral measurements, are illustrated with results of work done in arid zones. A normalization of spatial variability of land surface evaporation is proposed by defining a location-dependent potential evaporation and surface temperature range. Examples of the application of remote based estimates of evaporation to hydrological modeling studies in Egypt and Argentina are presented. RP MENENTI, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. OI Menenti, Massimo/0000-0001-9176-4556 NR 60 TC 11 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 89 EP 100 DI 10.1016/0273-1177(93)90533-H PG 12 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200011 ER PT J AU ORMSBY, JP ENGMAN, ET AF ORMSBY, JP ENGMAN, ET TI HYDROSAT - AN INSTRUMENT PLATFORM FOR HYDROLOGY SO ADVANCES IN SPACE RESEARCH LA English DT Article ID SOIL-MOISTURE; SYSTEM AB This paper dicusses a multi-sensor satellite approach for the study of hydrological applications. Spectral as well as spatial and temporal characteristics of specific operational and planned instruments applicable to hydrology are presented. A hydrology specific series of sensors are proposed to fill the gaps not covered by the current and planned systems. We have called this hypothetical platform HYDROSAT. In additon the trade-offs between a geostationary satellite and a polar orbiter are explored. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771. RP ORMSBY, JP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROSPHER PROC LAB,CODE 970,GREENBELT,MD 20771, USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 101 EP 104 DI 10.1016/0273-1177(93)90534-I PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200012 ER PT J AU ONEILL, PE JACKSON, TJ CHAUHAN, NS SEYFRIED, MS AF ONEILL, PE JACKSON, TJ CHAUHAN, NS SEYFRIED, MS TI MICROWAVE SOIL-MOISTURE ESTIMATION IN HUMID AND SEMIARID WATERSHEDS SO ADVANCES IN SPACE RESEARCH LA English DT Article ID SYSTEM AB Knowledge of the interactions of climate, soil condition, and vegetation is necessary in order to understand and quantify die role of hydrology in global processes. State variables such as soil moisture Play an important role in determining land surface moisture and energy fluxes and in partitioning precipitation into runoff and storage terms. To provide accurate descriptions of hydrological components that are relevant at local to regional scales, the integrating properties of remote sensing are utilized, especially at the microwave wavelengths most sensitive to water content. Preliminary results of four ongoing investigations designed to study land surface hydrologic-atmospheric interactions in humid and semiarid watersheds will be discussed. These studies have focused on the use of active and passive microwave sensors to estimate the spatial and temporal distribution of soil moisture at the catchment scale, and the eventual use of this information in the analysis and prediction of the associated hydrological processes. C1 USDA ARS,NW WATERSHED RES CTR,BOISE,ID 83712. USDA ARS,BELTSVILLE AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705. RP ONEILL, PE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,HYDROSPHER PROC LAB,HYDROL SCI BRANCH 974,GREENBELT,MD 20771, USA. RI O'Neill, Peggy/D-2904-2013 NR 8 TC 4 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 115 EP 118 DI 10.1016/0273-1177(93)90536-K PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200014 ER PT J AU WOOD, EF LIN, DS MANCINI, M THONGS, D TROCH, PA JACKSON, TJ FAMIGLIETTI, JS ENGMAN, ET AF WOOD, EF LIN, DS MANCINI, M THONGS, D TROCH, PA JACKSON, TJ FAMIGLIETTI, JS ENGMAN, ET TI INTERCOMPARISONS BETWEEN PASSIVE AND ACTIVE MICROWAVE REMOTE-SENSING, AND HYDROLOGICAL MODELING FOR SOIL-MOISTURE SO ADVANCES IN SPACE RESEARCH LA English DT Article AB Soil moisture estimates from a distributed hydrological model and two microwave remote sensors (Push Broom Microwave Radiometer and Synthetic Aperture Radar) were compared with the ground measurements collected during the MAC-HYDRO'90 experiment over a 7.4-km2 watershed in central Pennsylvania. Various information, including rainfall, soil properties, land cover, topography and remote sensing imagery, were integrated and analyzed using an image integration technique. It is found that the hydrological model and both microwave sensors successfully pick up the temporal variation of soil moisture. Results also indicate the spatial soil moisture pattern can be remotely sensed within reasonable accuracy using existing algorithms. Watershed averaged soil moisture estimates from the hydrological model are wetter than remotely sensed data. It is difficult to conclude which instrument yield better performance for the studied case. The choice will be based on the intended applications and information that is available. C1 USDA ARS,BELTSVILLE AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP WOOD, EF (reprint author), PRINCETON UNIV,DEPT CIVIL ENGN & OPERAT RES,PRINCETON,NJ 08544, USA. OI Wood, Eric/0000-0001-7037-9675 NR 13 TC 18 Z9 18 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 167 EP 176 DI 10.1016/0273-1177(93)90541-I PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200019 ER PT J AU MENENTI, M AZZALI, S VERHOEF, W VANSWOL, R AF MENENTI, M AZZALI, S VERHOEF, W VANSWOL, R TI MAPPING AGROECOLOGICAL ZONES AND TIME-LAG IN VEGETATION GROWTH BY MEANS OF FOURIER-ANALYSIS OF TIME-SERIES OF NDVI IMAGES SO ADVANCES IN SPACE RESEARCH LA English DT Article AB Examples are presented of applications of a Fast Fourier transform algorithm to analyse time series of images of Normalized Difference Vegetation Index (NDVI) values. The results obtained for a case study on Zambia indicated that differences in vegetation development among map units of an existing agroclimatic map were not significant, while reliable differences were observed among the map units obtained using the Fourier analysis. C1 DLO,WINAND STARING CTR INTEGRATED LAND SOIL & WATER RES,WAGENINGEN,NETHERLANDS. NATL AEROSP LAB,EMMELOORD,NETHERLANDS. RP MENENTI, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,HYDROSPHER PROC LAB,GREENBELT,MD 20771, USA. RI Verhoef, Wouter/D-4399-2009; OI Menenti, Massimo/0000-0001-9176-4556 NR 16 TC 72 Z9 81 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 233 EP 237 DI 10.1016/0273-1177(93)90550-U PG 5 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200027 ER PT J AU MYNENI, RB CHOUDHURY, BJ AF MYNENI, RB CHOUDHURY, BJ TI SYNERGISTIC USE OF OPTICAL AND MICROWAVE DATA IN AGROMETEOROLOGICAL APPLICATIONS SO ADVANCES IN SPACE RESEARCH LA English DT Article ID LIQUID WATER-CONTENT; SATELLITE DATA; RADIATION; PHOTOSYNTHESIS; REFLECTANCE; CANOPIES; INDEX AB Remotely sensed optical and microwave data can be synergistically used to infer land surface properties. Optical data can be used to estimate surface albedo, radiation absorption by vegetation canopies and their photosynthetic efficiencies. Vegetation canopy reflectance at red and near-infrared wavelengths can be used to correct for vegetation effect on microwave emissivities at low frequencies for estimating soil moisture. Optical data can also provide information about surface and air temperatures, precipitable water vapor, cloud top temperature and its water content. This information can be utilized to correct microwave data for atmospheric effects. These points are illustrated with theoretical analyses and by application to satellite data. The basic physical mechanisms operative at the various wavelengths are also discussed. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771. RP MYNENI, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,MAIL CODE 923,GREENBELT,MD 20771, USA. RI Myneni, Ranga/F-5129-2012 NR 40 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 J9 ADV SPACE RES JI Adv. Space Res. PD MAY PY 1993 VL 13 IS 5 BP 239 EP 248 DI 10.1016/0273-1177(93)90551-L PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA KY212 UT WOS:A1993KY21200028 ER PT J AU CHAE, SK LEE, HS AF CHAE, SK LEE, HS TI DETERMINATION OF RADIATIVE TRANSPORT-PROPERTIES OF PARTICLE SUSPENSIONS BY A SINGLE-SCATTERING EXPERIMENT SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article AB A light-scattering experiment on particles was performed to determine radiative transport properties of the suspension. Extinction coefficient, scattering coefficient, and phase function are the important properties. A generalized light-scattering experimental setup was designed and constructed to perform systematic research on light scattering by particles. By measuring the transmitted energy and angular scattered-energy distribution around a particle suspension, complete information on radiative transport properties could be obtained. This study focused on the performance of the experimental setup with purely scattering particle suspensions. Transparent polymer monospheres with diameters of 0.091, 0.546, 1.001, and 7.04 mum were used in separate suspensions of water for this study. The radiative transport properties obtained experimentally are compared with results from Mie theory. The single-scattering condition was examined and maintained during this experiment. The number concentrations of all but the smallest particles were independently measured using an optical liquid-borne particle counter. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CHAE, SK (reprint author), UNIV MINNESOTA,DEPT MECH ENGN,PARTICLE TECHNOL LAB,MINNEAPOLIS,MN 55455, USA. NR 27 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAY PY 1993 VL 18 IS 4 BP 389 EP 402 DI 10.1080/02786829308959612 PG 14 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA KY254 UT WOS:A1993KY25400006 ER PT J AU CHAE, SK LEE, HS AF CHAE, SK LEE, HS TI DETERMINATION OF REFRACTIVE-INDEXES OF DYED POLYMER MONOSPHERES SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID LATEX-PARTICLES; SCATTERING; COUNTERS AB The complex refractive indices of commercial composite spherical particles (black dyed [D(p) = 1.041 mum] and red dyed [D(p) = 0.999 mum]) were determined by two different methods. The first method measured angular scattered-energy distributions to determine experimental phase functions that were compared with Mie phase functions. The second method examined several mixture rules to obtain the effective refractive indices of dyed polymer monospheres. The refractive indices of black and red dyes were measured independently for the mixture rule study. The effect of different refractive indices on the particle sizing accuracy was investigated using an optical liquid-borne particle counter and a wafer surface scanner. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CHAE, SK (reprint author), UNIV MINNESOTA,DEPT MECH ENGN,PARTICLE TECHNOL LAB,MINNEAPOLIS,MN 55455, USA. NR 27 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAY PY 1993 VL 18 IS 4 BP 403 EP 417 DI 10.1080/02786829308959613 PG 15 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA KY254 UT WOS:A1993KY25400007 ER PT J AU STONE, NH CANDIDI, M AF STONE, NH CANDIDI, M TI TETHERING A NEW TECHNOLOGY SO AEROSPACE AMERICA LA English DT Article RP STONE, NH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD MAY PY 1993 VL 31 IS 5 BP 14 EP 18 PG 5 WC Engineering, Aerospace SC Engineering GA KY788 UT WOS:A1993KY78800004 ER PT J AU DOODY, D AF DOODY, D TI MAGELLAN MAPPING UPDATE - A MATTER OF GRAVITY SO AEROSPACE AMERICA LA English DT Article RP DOODY, D (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD MAY PY 1993 VL 31 IS 5 BP 20 EP 24 PG 5 WC Engineering, Aerospace SC Engineering GA KY788 UT WOS:A1993KY78800005 ER PT J AU BATINA, JT AF BATINA, JT TI IMPLICIT UPWIND SOLUTION ALGORITHMS FOR 3-DIMENSIONAL UNSTRUCTURED MESHES SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 30TH AEROSPACE SCIENCES MEETING CY JAN 06-09, 1992 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT AB The development of implicit upwind algorithms for the solution of the three-dimensional, time-dependent Euler equations on unstructured tetrahedral meshes is described. The implicit temporal discretization involves either a two-sweep Gauss-Seidel relaxation procedure, a two-sweep point-Jacobi relaxation procedure, or a single-sweep point-implicit procedure; the upwind spatial discretization is based on the flux-difference splitting of Roe. Detailed descriptions of the three implicit solution algorithms are given, and calculations for the Boeing 747 transport configuration are presented to demonstrate the algorithms. Advantages and disadvantages of the implicit algorithms are discussed. A steady-state solution for the 747 configuration, obtained at transonic flow conditions using a mesh of over 100,000 cells, required less than 1 h of CPU time on a Cray-2 computer, thus demonstrating the speed and robustness of the general capability. RP BATINA, JT (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,UNSTEADY AERODYNAM BRANCH,HAMPTON,VA 23681, USA. NR 10 TC 14 Z9 20 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 801 EP 805 DI 10.2514/3.11685 PG 5 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400001 ER PT J AU KIM, SW BENSON, TJ AF KIM, SW BENSON, TJ TI FLUID-FLOW OF A ROW OF JETS IN CROSS-FLOW - A NUMERICAL STUDY SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 30TH AEROSPACE SCIENCES MEETING CY JAN 06-09, 1992 CL RENO, NV SP AMER INST AERONAUT & ASTRONAUT ID SCALE TURBULENCE MODEL; CHANNEL AB A detailed computer-visualized flowfield of a row of jets in a confined crossflow is presented. The Reynolds-averaged Navier-Stokes equations are solved by using a finite volume method that incorporates a partial differential equation for incremental pressure to obtain a divergence-free flowfield. The turbulence is described by a multiple-time-scale turbulence model. The computational domain includes the upstream region of the circular jet so that the interaction between the jet and the crossflow is simulated accurately. It is shown that the row of jets in the crossflow is characterized by a highly complex flowfield that includes a horseshoe vortex and two helical vortices whose secondary velocity components are corotating in space. It is also shown that the horseshoe vortex is a ring of reversed flows located along the circumference of the jet exit. RP KIM, SW (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,MS 5-11,CLEVELAND,OH 44135, USA. NR 18 TC 32 Z9 36 U1 1 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 806 EP 811 DI 10.2514/3.11686 PG 6 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400002 ER PT J AU LEE, EM BATINA, JT AF LEE, EM BATINA, JT TI RESULTS FROM A CONICAL EULER METHODOLOGY DEVELOPED FOR UNSTEADY VORTICAL FLOWS SO AIAA JOURNAL LA English DT Article AB IN recent years, the understanding and prediction of the complex flows about high-performance aircraft at high ' angles of attack have generated much interest within the fluid dynamics community. These aircraft typically have thin, highly swept lifting surfaces that produce vortical flow over the leeward side of the vehicle at high angles of attack. This vortical flow can have beneficial effects on performance, such as lift augmentation at high angles of attack. However, it also may have adverse effects, such as structural fatigue due to tail buffet and stability and control problems due to wing rock, wing drop, nose slice, and pitch-up. Consequently, considerable experimental work has been done to understand the basic flow physics of vortical flows about delta wings at high angles of attack. Use of the more modern computational fluid dynamics techniques for the prediction of vortex-dominated flows has focused primarily on steady applications; there are notable exceptions where applications have been made to rolling delta wings undergoing forced harmonic motions.1-3 The objective of the current research is to study unsteady, vortex-dominated flowfields by using the conical Euler equations as a first step in investigating the three-dimensional problem. The purpose of this paper is to report on the development of a conical Euler analysis method to study unsteady, vortex-dominated flows about rolling delta wings undergoing either pulsed motion, forced harmonic motion, or free-to-roll motion. The full paper gives descriptions of the conical Euler flow solver and free-to-roll analysis. The flow solver involves a multistage, Runge-Kutta time-stepping scheme and a cell-centered, finite volume spatial discretization of the Euler equations on an unstructured grid of triangles. The code was modified to include the simultaneous time integration of the rigid-body equation of motion with the governing flow equations to allow for the additional analysis of the free-to-roll case. Results that demonstrate how the systematic analysis of the forced response of the delta wing can be used to predict the stable, unstable, and neutrally stable free response of the delta wing are presented in this Synoptic. The conical Euler methodology developed is directly extendable to three-dimensional calculations. RP LEE, EM (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,UNSTEADY AERODYNAM BRANCH,MAIL STOP 173,HAMPTON,VA 23665, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 818 EP 819 DI 10.2514/3.11690 PG 2 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400006 ER PT J AU HAHN, TO SHIH, TIP CHYU, WJ AF HAHN, TO SHIH, TIP CHYU, WJ TI NUMERICAL STUDY OF SHOCK-WAVE BOUNDARY-LAYER INTERACTIONS WITH BLEED SO AIAA JOURNAL LA English DT Article AB A numerical study was conducted to investigate how bleed through a two-dimensional slot affects shock-wave induced, boundary-layer separation on a flat plate. This study is based on the ensemble-averaged, compressible, Navier-Stokes equations closed by the Baldwin-Lomax, algebraic turbulence model. The algorithm used to obtain solutions was the implicit, partially split, two-factored scheme of Steger. This study examined the effects of the following parameters in controlling shock-wave induced flow separation: location of slot in relation to where the incident shock wave impinged on the boundary layer, size of slot in relation to the boundary-layer thickness, number of slots, spacings between slots, and strength of the incident shock wave. This study also showed the nature of the very complex flowfield about the slot or slots and how the plenum affects the bleed process. The results of this study are relevant to problems where bleed is used to control shock-wave induced, boundary-layer separation (e.g., inside jet engine inlets and wind tunnels). C1 NASA,AMES RES CTR,APPL AERODYNAM BRANCH,MOFFETT FIELD,CA 94035. RP HAHN, TO (reprint author), CARNEGIE MELLON UNIV,DEPT MECH ENGN,PITTSBURGH,PA 15213, USA. NR 7 TC 11 Z9 11 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 869 EP 876 DI 10.2514/3.11698 PG 8 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400014 ER PT J AU CHEN, KH PLETCHER, RH AF CHEN, KH PLETCHER, RH TI SIMULATION OF 3-DIMENSIONAL LIQUID SLOSHING FLOWS USING A STRONGLY IMPLICIT CALCULATION PROCEDURE SO AIAA JOURNAL LA English DT Article ID FLUID; DYNAMICS AB A coupled strongly implicit solution strategy for unsteady three-dimensional free surface flows has been developed based on an artificial compressibility formulation for the incompressible Navier-Stokes equations. A pseudotime term has been used in the continuity equation to permit time-accurate calculations to be achieved. The scheme appears capable of tracking the free surface reasonably accurately inside a partially filled spherical container undergoing a general rotating motion characteristic of that experienced by a spin-stabilized satellite. Five different free surface calculations have been presented. Some of the results exhibit an interesting Reynolds number dependent oscillatory behavior that is believed to be physical, although no experimental results appear to be available for verification to date. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. IOWA STATE UNIV SCI & TECHNOL,DEPT MICROBIOL & PARASITOL,AMES,IA 50011. NR 23 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 901 EP 910 DI 10.2514/3.11702 PG 10 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400018 ER PT J AU SRINIVASAN, GR BAEDER, JD AF SRINIVASAN, GR BAEDER, JD TI TURNS - A FREE-WAKE EULER/NAVIER-STOKES NUMERICAL-METHOD FOR HELICOPTER ROTORS SO AIAA JOURNAL LA English DT Note ID IMPULSIVE NOISE C1 JAI ASSOCIATES INC,MT VIEW,CA 94042. RP SRINIVASAN, GR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 13 TC 55 Z9 57 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1993 VL 31 IS 5 BP 959 EP 962 DI 10.2514/3.49036 PG 4 WC Engineering, Aerospace SC Engineering GA LC444 UT WOS:A1993LC44400028 ER PT J AU HALLORAN, BP BIKLE, DD HARRIS, J FOSKETT, HC MOREYHOLTON, E AF HALLORAN, BP BIKLE, DD HARRIS, J FOSKETT, HC MOREYHOLTON, E TI SKELETAL UNLOADING DECREASES PRODUCTION OF 1,25-DIHYROXYVITAMIN-D SO AMERICAN JOURNAL OF PHYSIOLOGY LA English DT Article DE IMMOBILIZATION; CALCITRIOL; METABOLIC CLEARANCE; BONE; VITAMIN-D; PARATHYROID HORMONE ID SIMULATED WEIGHTLESSNESS; BONE; IMMOBILIZATION; 1,25-DIHYDROXYVITAMIN-D; METABOLISM; INHIBITION; RATS AB The plasma concentration of 1,25-dihydroxyvitamin D [1,25(OH)2D] decreases during skeletal unloading and increases when normal weight bearing is restored. To determine whether these changes in plasma 1,25(OH)2D reflect changes in production, metabolic clearance, or both we measured the kinetics of 1,25(OH)2D metabolism in rats whose skeletons were normally loaded, unloaded, or reloaded after a period of nonweight bearing. Skeletal unloading produced a transient but striking fall in the production (-73%) and plasma concentration (-72%) of 1,25(OH)2D without having a significant effect (<20%) on metabolic clearance. Skeletal reloading returned production to normal. Bone formation predictably decreased during unloading and returned to normal after return to weight bearing. No consistent changes in blood ionized calcium, plasma immunoreactive parathyroid hormone (irPTH), or plasma phosphorus occurred. These data suggest that the changes in plasma 1,25(OH)2D associated with changes in skeletal weight bearing primarily reflect changes in 1,25(OH)2D production. The data provide no evidence that the changes in 1,25(OH)2D production are a consequence of changes in blood ionized calcium, plasma irPTH, or phosphorus. C1 UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,DIV BIOMED RES,MOFFETT FIELD,CA 94035. RP HALLORAN, BP (reprint author), VET AFFAIRS MED CTR,DIV ENDOCRINOL,MC 111N,4150 CLEMENT ST,SAN FRANCISCO,CA 94121, USA. NR 30 TC 27 Z9 27 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0002-9513 J9 AM J PHYSIOL JI Am. J. Physiol. PD MAY PY 1993 VL 264 IS 5 BP E712 EP E716 PN 1 PG 5 WC Physiology SC Physiology GA LD346 UT WOS:A1993LD34600039 PM 8498493 ER PT J AU GOTTLIEB, D TURKEL, E AF GOTTLIEB, D TURKEL, E TI SPECIAL ISSUE TO HONOR ABARBANEL,SAUL ON HIS 60TH BIRTHDAY - DEDICATION SO APPLIED NUMERICAL MATHEMATICS LA English DT Editorial Material C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. TEL AVIV UNIV,SACKLER FAC EXACT SCI,SCH MATH SCI,IL-69978 TEL AVIV,ISRAEL. RP GOTTLIEB, D (reprint author), BROWN UNIV,DIV APPL MATH,BOX F,PROVIDENCE,RI 02912, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 1993 VL 12 IS 1-3 BP 1 EP 2 DI 10.1016/0168-9274(93)90108-4 PG 2 WC Mathematics, Applied SC Mathematics GA LH788 UT WOS:A1993LH78800001 ER PT J AU CARPENTER, MH GOTTLIEB, D ABARBANEL, S AF CARPENTER, MH GOTTLIEB, D ABARBANEL, S TI STABLE AND ACCURATE BOUNDARY TREATMENTS FOR COMPACT, HIGH-ORDER FINITE-DIFFERENCE SCHEMES SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID APPROXIMATIONS AB The stability characteristics of various compact fourth- and sixth-order spatial operators are used to assess the theory of Gustafsson, Kreiss and Sundstrom (G-K-S) for the semidiscrete initial boundary value problem (IBVP). In all cases, favorable comparisons are obtained between G-K-S theory, eigenvalue determination, and numerical simulation. The conventional definition of stability then is sharpened to include only those spatial discretizations that are asymptotically stable (bounded, left half-plane (LHP) eigenvalues). It is shown that many of the higher-order schemes that are G-K-S stable are not asymptotically stable. A series of compact fourth- and sixth-order schemes is developed, all of which are asymptotically and G-K-S stable for the scalar case. A systematic technique is then presented for constructing stable and accurate boundary closures of various orders. The technique uses the semidiscrete summation-by-parts energy norm to guarantee asymptotic and G-K-S stability of the resulting boundary closure. Various fourth-order explicit and implicit discretizations are presented, all of which satisfy the summation-by-parts energy norm. C1 BROWN UNIV,DEPT APPL MATH,PROVIDENCE,RI 02912. TEL AVIV UNIV,DEPT MATH SCI,DIV APPL MATH,IL-69978 TEL AVIV,ISRAEL. RP CARPENTER, MH (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23681, USA. NR 12 TC 46 Z9 47 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 1993 VL 12 IS 1-3 BP 55 EP 87 DI 10.1016/0168-9274(93)90112-5 PG 33 WC Mathematics, Applied SC Mathematics GA LH788 UT WOS:A1993LH78800005 ER PT J AU SALAS, MD AF SALAS, MD TI SHOCK-WAVE INTERACTION WITH AN ABRUPT AREA CHANGE SO APPLIED NUMERICAL MATHEMATICS LA English DT Article AB The wave patterns that occur when a shock wave interacts with an abrupt area change are analyzed in terms of the incident shock wave Mach number and area jump ratio. The solutions predicted by a self-similar model are in good agreement with those obtained numerically from the quasi-one-dimensional time-dependent Euler equations. The entropy production for the wave system is defined and the principle of minimum entropy production is used to resolve a nonuniqueness problem fo the self-similar model. RP SALAS, MD (reprint author), NASA,LANGLEY RES CTR,DIV FLUID DYNAM,HAMPTON,VA 23681, USA. NR 13 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 1993 VL 12 IS 1-3 BP 239 EP 256 DI 10.1016/0168-9274(93)90121-7 PG 18 WC Mathematics, Applied SC Mathematics GA LH788 UT WOS:A1993LH78800014 ER PT J AU TURKEL, E AF TURKEL, E TI REVIEW OF PRECONDITIONING METHODS FOR FLUID-DYNAMICS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID NAVIER-STOKES EQUATIONS; MACH NUMBER EULER; INCOMPRESSIBLE-FLOW; TIME; CONVERGENCE; COMPUTATION; SCHEMES AB We consider the use of preconditioning methods to accelerate the convergence to a steady state for both the incompressible and compressible fluid dynamic equations. Most of the analysis relies on the inviscid equations though some applications for viscous flow are considered. The preconditioning can consist of either a matrix or a differential operator acting on the time derivatives. Hence, in the steady state the original steady solution is obtained. For finite difference methods the preconditioning can change and improve the steady-state solutions. Several preconditioners previously discussed are reviewed and some new approaches are presented. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. RP TURKEL, E (reprint author), TEL AVIV UNIV,SACKLER FAC EXACT SCI,SCH MATH SCI,IL-69978 TEL AVIV,ISRAEL. RI Turkel, Eli/F-6297-2011 OI Turkel, Eli/0000-0003-4273-0303 NR 62 TC 108 Z9 112 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 1993 VL 12 IS 1-3 BP 257 EP 284 DI 10.1016/0168-9274(93)90122-8 PG 28 WC Mathematics, Applied SC Mathematics GA LH788 UT WOS:A1993LH78800015 ER PT J AU MEEHAN, R SMITH, M REED, R SAMS, C AF MEEHAN, R SMITH, M REED, R SAMS, C TI POTENTIAL NEUROENDOCRINE MECHANISMS OF T-CELL DYSFUNCTION IN SLE PATIENTS SO ARTHRITIS AND RHEUMATISM LA English DT Meeting Abstract C1 UNIV COLORADO,HLTH SCI CTR,DENVER,CO 80262. USAF ACAD,COLORADO SPRINGS,CO 80840. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0004-3591 J9 ARTHRITIS RHEUM JI Arthritis Rheum. PD MAY PY 1993 VL 36 IS 5 SU S BP R6 EP R6 PG 1 WC Rheumatology SC Rheumatology GA LD569 UT WOS:A1993LD56900006 ER PT J AU STANDISH, EM AF STANDISH, EM TI PLANET-X - NO DYNAMIC EVIDENCE IN THE OPTICAL OBSERVATIONS SO ASTRONOMICAL JOURNAL LA English DT Article ID VOYAGER TRACKING DATA; RADIO SCIENCE; GRAVITY-FIELD; SOLAR-SYSTEM; EPHEMERIDES; PRECESSION; PIONEER; MASSES AB It is shown that the alleged ''unexplained anomalies in the motion of Uranus'' disappear when one properly accounts for the correct value of the mass of Neptune and properly adjusts the orbit of Uranus to the observational data. Also, it is shown that each of the ''irregularities in the measured positions of Neptune'' has a complete explanation within the framework of the presently known solar system. As a check of certainty, an actual planetary ephemeris is integrated which well fits the observations of Uranus. Minor systematic errors do remain in the data, but they are very small; they are easily explained by a number of uncertainties in the observations themselves. There is now known to be a mass concentration of significant size in the outer solar system-1992 QB1. In comparison to any of the major planets, though, this object is miniscule. For the meridian circle observations, there is still no evidence which requires or even indicates the existence of any planet-sized object; there remains no need to hypothesize the existence of a tenth planet in the solar system. RP STANDISH, EM (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 TC 32 Z9 32 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1993 VL 105 IS 5 BP 2000 EP 2006 DI 10.1086/116575 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ644 UT WOS:A1993KZ64400034 ER PT J AU COHEN, M WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D AF COHEN, M WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D TI SPECTRAL IRRADIANCE CALIBRATION IN THE INFRARED .3. THE INFLUENCE OF CO AND SIO (VOL 104, PG 2045, 1992) SO ASTRONOMICAL JOURNAL LA English DT Correction, Addition C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP COHEN, M (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,601 CAMPBELL HALL,BERKELEY,CA 94720, USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1993 VL 105 IS 5 BP 2007 EP 2007 DI 10.1086/116576 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ644 UT WOS:A1993KZ64400036 ER PT J AU COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D AF COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D TI SPECTRAL IRRADIANCE CALIBRATION IN THE INFRARED .2. (VOL 104, PG 2030, 1992) SO ASTRONOMICAL JOURNAL LA English DT Correction, Addition C1 JAMIESON SCI & ENGN INC,SCOTTS VALLEY,CA 95066. UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP COHEN, M (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,BERKELEY,CA 94720, USA. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 1 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1993 VL 105 IS 5 BP 2008 EP 2008 DI 10.1086/116578 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ644 UT WOS:A1993KZ64400038 ER PT J AU COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D AF COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D TI SPECTRAL IRRADIANCE CALIBRATION IN THE INFRARED .1. (VOL 104, PG 1650, 1992) SO ASTRONOMICAL JOURNAL LA English DT Correction, Addition C1 JAMIESON SCI & ENGN INC,SCOTTS VALLEY,CA 95066. UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP COHEN, M (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,BERKELEY,CA 94720, USA. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 1 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1993 VL 105 IS 5 BP 2008 EP 2008 DI 10.1086/116578 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ644 UT WOS:A1993KZ64400037 ER PT J AU COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D AF COHEN, M WALKER, RG BARLOW, MJ DEACON, JR WITTEBORN, FC CARBON, DF AUGASON, G WOODEN, D BREGMAN, J GOORVITCH, D TI SPECTRAL IRRADIANCE CALIBRATION IN THE INFRARED .3. (VOL 104, PG 2045, 1992) SO ASTRONOMICAL JOURNAL LA English DT Correction, Addition C1 JAMIESON SCI & ENGN INC,SCOTTS VALLEY,CA 95066. UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP COHEN, M (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,BERKELEY,CA 94720, USA. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 1 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1993 VL 105 IS 5 BP 2008 EP 2008 DI 10.1086/116578 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ644 UT WOS:A1993KZ64400039 ER PT J AU HUNTER, SD BERTSCH, DL DINGUS, BL FICHTEL, CE HARTMAN, RC KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL SCHNEID, E SREEKUMAR, P THOMPSON, DJ AF HUNTER, SD BERTSCH, DL DINGUS, BL FICHTEL, CE HARTMAN, RC KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL SCHNEID, E SREEKUMAR, P THOMPSON, DJ TI DETECTION OF HIGH-ENERGY GAMMA-RAYS FROM BL LAC PKS 0235+164 BY THE EGRET TELESCOPE ON THE COMPTON OBSERVATORY SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE GAMMA-RAYS, OBSERVATIONS; BL LACERTAE OBJECTS, INDIVIDUAL PKS 0235+164 ID RADIO-SOURCES; RELATIVISTIC JETS; RADIATION; OBJECT; AO-0235+164; ARTIFACTS; QSOS AB The BL Lac object PKS 0235+164 was observed with the Energetic Gamma Ray Telescope Experiment (EGRET) on the Compton Observatory from February 20, 1992 to March 5, 1992. During this period, PKS 0235+164 was detected with a flux level above 100 MeV of (8.0 +/- 1.2) x 10(-7) photons cm-2 s-1. The spectra is well represented by a power law with spectral index 1.85 +/- 0.19. During this observation there is no evidence for time variation of the flux. C1 MAX PLANCK INST EXTRATERR PHYS, W-8046 GARCHING, GERMANY. HAMPDEN SYDNEY COLL, HAMPDEN SYDNEY, VA 23943 USA. STANFORD UNIV, HANSEN EXPTL PHYS LAB, STANFORD, CA 94305 USA. UNIV SPACE RES ASSOC, WASHINGTON, DC USA. GRUMMAN AEROSP CORP, BETHPAGE, NY 11714 USA. NASA, NRC, WASHINGTON, DC 20546 USA. COMP SCI CORP, COMPTON SCI SUPPORT CTR, SILVER SPRING, MD 20910 USA. RP HUNTER, SD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 662, GREENBELT, MD 20771 USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 47 TC 27 Z9 27 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 1993 VL 272 IS 1 BP 59 EP 62 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LA022 UT WOS:A1993LA02200007 ER PT J AU LANZ, T ARTRU, MC DIDELON, P MATHYS, G AF LANZ, T ARTRU, MC DIDELON, P MATHYS, G TI THE GA-II LINES IN THE RED SPECTRUM OF AP STARS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE STARS, ABUNDANCE; STARS, ATMOSPHERES; STARS, CHEMICALLY PECULIAR; STARS, VARIABLES; STARS, FUNDAMENTAL PARAMETERS ID B-TYPE STARS; CHEMICALLY PECULIAR STARS; EFFECTIVE TEMPERATURES; BOLOMETRIC CORRECTIONS; OSCILLATOR-STRENGTHS; ANGULAR DIAMETERS; MODEL ATMOSPHERES; MAGNETIC-FIELD; SI STARS; PHOTOMETRY AB We report first observations of the Ga II lambda633.4 line in the red spectrum of Ap stars. This line is present in the spectrum of 16 out of 45 Ap stars of our sample, translating to large gallium overabundances. While most HgMn stars are gallium-rich, we have observed strong gallium lines in several magnetic stars. We have derived LTE abundances from this line after reviewing all needed atomic data and stellar parameters. In particular, a new calibration of the Geneva photometry for the effective temperature of the magnetic Ap stars is presented. LTE abundances are compared to previous analyses of the ultraviolet resonance lines, and they are about 1 dex larger. This large discrepancy might possibly be explained by departures from LTE or by the stratification of gallium predicted by the radiative diffusion theory. We present the variations of the Ga II line strength during the rotation period of three magnetic Ap stars; from the variations of silicon and of the longitudinal component of the magnetic field it appears that gallium accumulates around magnetic poles. Moreover, we suggest that secular changes in the gallium surface abundance on time-scales of about 1-2 10(8) yr might explain why some Ap HgMn stars are not gallium-rich. C1 UNIV LAUSANNE, INST ASTRON, CH-1290 CHAVANNES DES BOIS, SWITZERLAND. ECOLE NORMALE SUPER LYON, PHYS LAB, F-69364 LYON 07, FRANCE. OBSERV LYON, F-69230 ST GENIS LAVAL, FRANCE. OBSERV STRASBOURG, F-67000 STRASBOURG, FRANCE. EUROPEAN SO OBSERV, SANTIAGO 19, CHILE. RP LANZ, T (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 681, GREENBELT, MD 20771 USA. NR 56 TC 27 Z9 27 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 1993 VL 272 IS 2 BP 465 EP 476 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC646 UT WOS:A1993LC64600016 ER PT J AU QUIN, DA DOYLE, JG BUTLER, CJ BYRNE, PB SWANK, JH AF QUIN, DA DOYLE, JG BUTLER, CJ BYRNE, PB SWANK, JH TI ROTATIONAL MODULATION AND FLARES ON RS CANUM VENATICORUM AND BY DRACONIS STARS .17. UV SPECTROSCOPY AND OPTICAL PHOTOMETRY OF AU MICROSCOPII IN 1986 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE UV SPECTROSCOPY; ROTATIONAL MODULATION; PLAGES; EMISSION MEASURE; RADIATIVE LOSSES ID HUBBLE SPACE TELESCOPE; ULTRAVIOLET CALIBRATION; TRANSITION REGION; OUTER ATMOSPHERES; DWARF STARS; IUE; CHROMOSPHERES; SPECTRA; CORONAE; FLUXES AB We present IUE spectroscopy and optical photometry of the active late type star AU Mic. The UV spectroscopy allow us to measure the chromospheric and transition region line fluxes. No detectable variations attributable to rotational modulation were evident in either the chromospheric lines or optical bands. We have produced an emission measure curve for the quiescent state of AU Mic, which spans a temperature range 4.0 less-than-or-equal-to log T(e) less-than-or-equal-to 7.6 when coupled with previous X-ray flux measurements. The quiescent radiative losses per unit surface area over the above temperature range is almost-equal-to 8 10(7) erg cm-2 s-1. C1 QUEENS UNIV BELFAST, DEPT PURE & APPL PHYS, BELFAST BT7 1NN, ANTRIM, NORTH IRELAND. NASA, GODDARD SPACE FLIGHT CTR, CODE 668, GREENBELT, MD 20771 USA. RP QUIN, DA (reprint author), ARMAGH OBSERV, COLL HILL, ARMAGH BT61 9DG, NORTH IRELAND. RI Swank, Jean/F-2693-2012 NR 33 TC 16 Z9 16 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 1993 VL 272 IS 2 BP 477 EP 485 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LC646 UT WOS:A1993LC64600017 ER PT J AU LUO, XC SCHRAMM, DN AF LUO, XC SCHRAMM, DN TI KURTOSIS, SKEWNESS, AND NON-GAUSSIAN COSMOLOGICAL DENSITY PERTURBATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, THEORY; LARGE-SCALE STRUCTURE OF UNIVERSE ID LARGE-SCALE STRUCTURE; FLUCTUATION SPECTRA; COSMIC STRUCTURE; EVOLUTION; CLUSTERS; GALAXIES; UNIVERSE; TEXTURE AB Cosmological topological defects as well as some nonstandard inflation models can give rise to non-Gaussian density perturbations. Skewness and kurtosis are the third and fourth moments that measure the deviation of a distribution from a Gaussian. Measurement of these moments for the cosmological density field and for the microwave background temperature anisotropy can provide a test of the Gaussian nature of the primordial fluctuation spectrum. In the case of the density field, the importance of measuring the kurtosis is stressed since it will be preserved through the weakly nonlinear gravitational evolution epoch. Current constraints on skewness and kurtosis of primeval perturbations are obtained from the observed density contrast deltarho/rho on small scales and from recent COBE observations of temperature anisotropies on large scales. It is also shown how, in principle, future microwave anisotropy experiments might be able to reveal the initial skewness and kurtosis. It is shown that present data argue that if the initial spectrum is adiabatic, then it is probably Gaussian, but non-Gaussian isocurvature fluctuations are still allowed, and these are what topological defects provide. C1 NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP LUO, XC (reprint author), UNIV CHICAGO,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 43 TC 39 Z9 39 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 33 EP 42 DI 10.1086/172567 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000004 ER PT J AU VENTURI, T GIOVANNINI, G FERETTI, L COMORETTO, G WEHRLE, AE AF VENTURI, T GIOVANNINI, G FERETTI, L COMORETTO, G WEHRLE, AE TI VLBI OBSERVATIONS OF A COMPLETE SAMPLE OF RADIO GALAXIES .2. THE PARSEC-SCALE STRUCTURE OF NGC-315 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC-315); GALAXIES, NUCLEI; RADIO CONTINUUM, GALAXIES; TECHNIQUES, INTERFEROMETRIC ID ELLIPTICAL GALAXIES; NUCLEAR JET; NGC 315; MOTION; MODEL; M87; VLA AB We present multifrequency radio observations of the low-luminosity (Fanaroff-Riley type 1) radio galaxy NGC 315 at parsec resolution. The observations were obtained at 1.6, 5, and 8.4 GHz with the European and US VLBI networks. In addition VLA observations were used to obtain arcsec resolution maps at the same frequencies. The radio morphology of NGC 315 is asymmetric at milliarcsec resolution. It shows nuclear emission with a core size of 0.05 pc, and a one-sided jet. We place a limit on the milliarcsec jet to counterjet brightness ratio of B(jet)/B(cjet) greater-than-or-equal-to 50 at 1.6 GHz. At arcsec resolution we see a counterjet which is shorter and much more diffuse than the main jet. We derive a spectral index profile at parsec resolution, and estimate the physical conditions in the parsec-scale jet. If we assume that the parsec-scale asymmetry is caused by Doppler boosting of an intrinsically identical jet-counterjet pair, the derived brightness ratio gives beta cos theta greater than or similar to 0.54, which gives an angle theta between the source axis and the line of sight less than or similar to 58-degrees. However, Doppler boosting cannot account for the asymmetry observed on the arcsec scale, given the much lower velocity flow estimated for the arcsec jet. This, together with the lack of any visible motion of the features in the maps at different epochs, suggests that an intrinsic asymmetry in the nuclear engine of NGC 315 is likely to be responsible for the observed radio asymmetry. C1 UNIV BOLOGNA,DIPARTIMENTO ASTRON,I-40133 BOLOGNA,ITALY. OSSERV ASTROFISICO ARCETRI,I-50126 FLORENCE,ITALY. JET PROP LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91109. RP VENTURI, T (reprint author), CNR,IST RADIOASTRON,VIA IRNERIO 46,I-40126 BOLOGNA,ITALY. RI Comoretto, Giovanni/F-6854-2010; OI Feretti, Luigina/0000-0003-0312-6285; Venturi, Tiziana/0000-0002-8476-6307; Comoretto, Giovanni/0000-0002-5461-5962 NR 46 TC 48 Z9 48 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 81 EP 91 DI 10.1086/172571 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000008 ER PT J AU JENNINGS, DE BOYLE, RJ WIEDEMANN, GR MOSELEY, SH AF JENNINGS, DE BOYLE, RJ WIEDEMANN, GR MOSELEY, SH TI HIGH-RESOLUTION MIDINFRARED SPECTRA OF CO-II, NI-I, AND FE-II IN SN-1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, STARS; STARS, ABUNDANCES; SUPERNOVAE, INDIVIDUAL (SN-1987A) ID EXTRAGALACTIC DISTANCE SCALE; SUPERNOVA 1987A; LINE-PROFILES; ENERGY-LEVELS; SN 1987A; NICKEL; EXPANSION; VELOCITY; EMISSION; SN1987A AB Ground-based infrared observations of SN 1987A on day 612 after the explosion have yielded resolved line profiles of Co II, Ni I, Fe II at 10.52, 11.31, and 17.94 mum, respectively. The spectra were taken at a resolving power of approximately 1000 with an array grating spectrometer on the 4 m telescope of Cerro Tololo Inter-American Observatory. Based on the observed line intensities we have estimated the minimum mass of each ion: M(Co II) = (6.0 +/- 1.8) x 10(-5) M.; M(Ni I) = (1.1 +/- 0.1) X 10(-3) M.; and M(Fe II) = (8.0 +/- 1.5) x 10(-3) M.. From these we infer total masses for cobalt, nickel, and iron in the ejecta. The nickel and iron line profiles are markedly asymmetric. We interpret these as arising from two components, one centered on the stellar rest velocity with a approximately 3250 km s-1 full width, and the second at approximately + 1200 km s-1 with a approximately 1100 km s-1 full width. The asymmetry may represent a large-scale fracturing of the ejecta by Rayleigh-Taylor instabilities. C1 DICKINSON COLL,DEPT PHYS & ASTRON,CARLISLE,PA 17013. EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,INFRARED ASTROPHYS BRANCH,GREENBELT,MD 20771. RP JENNINGS, DE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,CODE 693,GREENBELT,MD 20771, USA. RI Moseley, Harvey/D-5069-2012; Jennings, Donald/D-7978-2012 NR 60 TC 10 Z9 10 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 277 EP 286 DI 10.1086/172586 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000023 ER PT J AU ANDERSON, JD ARMSTRONG, JW LAU, EL AF ANDERSON, JD ARMSTRONG, JW LAU, EL TI UPPER LIMITS FOR GRAVITATIONAL-RADIATION FROM SUPERMASSIVE COALESCING BINARIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; RADIATION MECHANISMS, GRAVITATIONAL ID SEARCH; WAVES AB Supermassive coalescing binary systems are important candidate generators of gravitational radiation in the millihertz frequency band accessible with spacecraft Doppler tracking experiments. Signals from such systems are of particular astrophysical interest for two reasons. First, precoalescence waveforms from such systems can be calculated confidently. Second, measurements of instantaneous wave amplitude, frequency, and frequency derivative give the distance to the source, independent of the masses in the binary system. In this paper we report a search for waves from supermassive coalescing binaries using a 10.5 day Pioneer 10 data set taken in 1988. Depending on the time to coalescence, the initial frequency of the wave, and the length of the observing interval, a coalescing binary waveform appears in the tracking record either as a sinusoid, a ''chirp,'' or as a more complicated signal. We searched our data for coalescing binary waveforms in all three regimes. We successfully detected a (fortuitous) ''chirp'' signal caused by the varying spin rate of the spacecraft; this nicely served as a calibration of the data quality and as a test of our analysis procedures on real data. We did not detect any signals of astronomical origin in the millihertz band to an upper limit approximately 7 x 10(-15) (rms amplitude). This is the first time spacecraft Doppler data have been analyzed for coalescing binary waveforms, and the upper limits reported here are the best to date for any waveform in the millihertz band. RP ANDERSON, JD (reprint author), JET PROP LAB,MAIL STOP 301-230,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 287 EP 292 DI 10.1086/172587 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000024 ER PT J AU LANDSMAN, W SIMON, T AF LANDSMAN, W SIMON, T TI A CATALOG OF STELLAR LYMAN-ALPHA FLUXES SO ASTROPHYSICAL JOURNAL LA English DT Article DE CATALOGS; STARS, CHROMOSPHERES; ULTRAVIOLET, INTERSTELLAR; ULTRAVIOLET, STARS ID LOCAL INTERSTELLAR-MEDIUM; ULTRAVIOLET EMISSION-LINES; HUBBLE-SPACE-TELESCOPE; LATE-TYPE STARS; COOL STARS; TRANSITION REGION; IUE OBSERVATIONS; LY-ALPHA; CHROMOSPHERIC ACTIVITY; ROTATIONAL MODULATION AB We present a catalog of stellar Lyalpha emission fluxes, based on new and archival images obtained with the International Ultraviolet Explorer (IUE) spacecraft. The fluxes have been corrected for the contamination caused by diffusely scattered solar Lyalpha by means of an extraction procedure that uses spatial information perpendicular to the dispersion direction in the IUE line-by-line images. The catalog includes 227 stars with detectable Lyalpha emission fluxes, and upper limits on the Lyalpha emission flux for another 48 stars. Multiple flux measurements are given for 52 stars. We present a model for correcting the observed Lyalpha flux for attenuation by the local interstellar medium, and we apply this model to derive intrinsic Lyalpha fluxes for 149 catalog stars which are located in low H I column density directions of the local interstellar medium. In our catalog, there are 14 late-A and early-F stars at B-V less-than-or-equal-to 0.29 that show detectable emission at Lyalpha. We find a linear correlation between the intrinsic Lyalpha flux and C II 1335 angstrom flux for stars with B-V > 0.60, but the A and F stars deviate from this relation in the sense that their Lyalpha flux is too low. We also find a good correlation between Lyalpha strength and coronal X-ray emission. This correlation holds over most of the H-R diagram, even for the F stars, where an X-ray deficit has previously been found relative to the transition region lines of C II and C IV. C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. RP LANDSMAN, W (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,CODE 681,GREENBELT,MD 20771, USA. NR 70 TC 37 Z9 37 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 305 EP 322 DI 10.1086/172589 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000026 ER PT J AU SMITH, MA POLIDAN, RS AF SMITH, MA POLIDAN, RS TI DYNAMIC PROCESSES IN BE STAR ATMOSPHERES .1. DIMPLE FORMATION IN THE HE-I LAMBDA-6678 LINE OF LAMBDA-ERIDANI SO ASTROPHYSICAL JOURNAL LA English DT Article DE LINE, PROFILES; STARS, EMISSION-LINE, BE; STARS, INDIVIDUAL (LAMBDA ERIDANI); ULTRAVIOLET, STARS ULTRAVIOLET, STARS ID RADIATION-DRIVEN WINDS; HOT LUMINOUS STARS; THERMODYNAMIC-EQUILIBRIUM; HYDROGEN; DISKS; B2E AB '' Dimples '' are ephemeral absorption features flanked by incipient blue/red emission in the He I lambda6678 line profiles of lambda Eri and several similar mild classical Be stars. They develop rapidly (approximately 15 minutes), last 2-4 hr, and are observed in this line on the average at least once per night, making them the most ubiquitous of the ''spectral transients '' appearing in the line profiles of at least some mild Be stars. Their formation may well be related to the unknown instability-causing mass-loss episodes in Be stars. In this paper we discuss simultaneous IUE and optical (lambda6678) time-serial observations of lambda Eri, together with near-simultaneous UV continuum observations made by Voyager 1, in 1990 October. We find several examples of weakenings of the C IV, N V resonance lines that coincide with the appearance of lambda6678 dimples. The absence of variations in other UV lines and in the UV continuum at the same time (IUE) or nearly the same time (Voyager) argues against dimples being caused by thermal variations from the underlying star. We suggest instead that the resonance line weakenings are caused by non-LTE effects associated with the condensation of high density structures at some elevation over the star. We present a simple model of an opaque (in the line only), essentially stationary slab which backscatters lambda6678 line radiation into a surrounding ''penumbral'' region. Lambda6678 photons are scattered a second time in this region back into the observer's line of sight and in the process acquire the local projected doppler shift from rotation. We examine several attributes of this mechanism and find that slabs typically have a projected radius of about 1 R., an elevation of approximately 0.10R*, and a density of approximately 2 x 10(11) cm-3. Our models can also match dimples resembling '' P Cygni '' features by permitting our model slabs to rise or fall and at the same time to move retrograde or prograde with respect to the stellar surface. Slabs would probably produce too little emission to be easily detected in the Halpha profile. Their detection in strong He I lines seems the best stategy among early Be stars. Slabs contain enough mass (> 10(-14) M.) and develop over such a large area and so rapidly as to greatly limit the number of mechanisms that could form them. Their rapid development spatially over the star precludes a purely thermal origin, e.g., from the propagation of a shock at the speed of sound. Yet, in terms of bulk motion dimples represent an exclusively low vertical-velocity phenomenon. Arguments can be advanced that dimples are not the results of ballistic tossings of blobs or of orbiting circumstellar ejecta. One viable mechanism for their formation requires that dimple-slabs condense from ambient rarefied material via a supersonically propagating instability. If this velocity is understood in terms of an Alfven wave, a case can be made that magnetic fields of greater-than-or-equal-to 100 G can exist in small regions above lambda Eri and many other mild classical Be stars. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & ASTROPHYS LAB,GREENBELT,MD 20771. RP SMITH, MA (reprint author), COMP SCI CORP,SCI PROGRAM,CSC IUE OBSERV,10000-A AEROSP RD,LANHAM,MD 20706, USA. NR 16 TC 26 Z9 26 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 323 EP 336 DI 10.1086/172590 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000027 ER PT J AU SCHMELZ, JT AF SCHMELZ, JT TI ELEMENTAL ABUNDANCES OF FLARING SOLAR PLASMA - ENHANCED NEON AND SULFUR SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, ABUNDANCES; SUN, FLARES ID RAY LINE EMISSION; PHOTOSPHERIC ABUNDANCES; RATIOS; FLARES AB Elemental abundances of two flares observed with the Solar Maximum Mission Flat Crystal Spectrometer are compared and contrasted. The first (a GOES Ml.5 flare) had a gradual rise and a slow decay, while the second (a GOES M5 flare) was much more impulsive. Simultaneous spectra of seven bright soft X-ray resonance lines provide information over a broad temperature range (2-35 x 10(6) K) and are available throughout both flares, making these events unique in the Solar Maximum Mission data base. Elemental abundances are investigated by means of a differential emission measure analysis. For the first flare, the plasma seemed to be characterized by coronal abundances but, for the second, the plasma composition could not be coronal, photospheric, or a linear combination of both. A good differential emission measure fit required enhanced neon such that Ne/O = 0.32 +/- 0.02, a value which is inconsistent with the current models of coronal abundances based on the elemental first-ionization potential, Similar values of enhanced neon are found for flaring plasma observed by the Solar Maximum Mission gamma-ray spectrometer, in He-3-rich solar energetic particle events, and in the decay phase of several long duration soft X-ray events. Sulfur is also enhanced in the impulsive flare, but not as dramatically as neon. These events are compared with two models which attempt to explain the enhanced values of neon and sulfur. C1 RHODES COLL, DEPT PHYS, MEMPHIS, TN 38112 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. NR 32 TC 55 Z9 55 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP 373 EP 381 DI 10.1086/172594 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY810 UT WOS:A1993KY81000031 ER PT J AU CHEN, W LIVIO, M GEHRELS, N AF CHEN, W LIVIO, M GEHRELS, N TI THE SECONDARY MAXIMA IN BLACK-HOLE X-RAY NOVA LIGHT CURVES - CLUES TOWARD A COMPLETE PICTURE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; BINARIES, CLOSE; BLACK HOLE PHYSICS; X-RAYS, STARS ID A0620-00; MODEL; TRANSIENTS AB We study the secondary maxima observed commonly in the X-ray/optical light curves of black hole X-ray novae and show that they can play an important role in our understanding of the X-ray nova phenomenon. We discuss the observational characteristics of the secondary maxima and possible mechanisms to produce them. We propose a complete scenario for black hole X-ray nova events. The main outburst is caused by a disk instability. The second maximum is caused by X-ray evaporation of the matter near the inner Lagrangian (L1) region when the disk becomes optically thin. The third maximum (or the final minioutburst) is due to a mass transfer instability caused by hard X-ray heating of the subphotospheric layers of the secondary during the outburst. We predict that the newly discovered X-ray nova GRO J0422 + 32 may develop a final mini-outburst in early 1993 and that its binary orbital period is less than 7 hr. C1 UNIV SPACE RES ASSOC,BALTIMORE,MD. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. TECHNION ISRAEL INST TECHNOL,DEPT PHYS,IL-32000 HAIFA,ISRAEL. RP CHEN, W (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Gehrels, Neil/D-2971-2012 NR 29 TC 53 Z9 53 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP L5 EP L8 DI 10.1086/186817 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY811 UT WOS:A1993KY81100002 ER PT J AU FRUM, CI OH, JJ COHEN, EA PICKETT, HM AF FRUM, CI OH, JJ COHEN, EA PICKETT, HM TI ROTATIONAL SPECTRA OF THE X2-SIGMA+ STATES OF CAH AND CAD SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, MOLECULES; MOLECULAR DATA ID CALCIUM HYDRIDE AB The rotational spectra of the 2SIGMA+ ground states of calcium monohydride and monodeuteride have been recorded in absorption between 250 and 700 GHz. The ps phase free radicals have been produced in a ceramic furnace by the reaction of elemental calcium with molecular hydrogen or deuterium in the presence of an electrical discharge. The molecular constants including the rotational constant, centrifugal distortion constants, spin-rotation constants, and magnetic hyperfine interaction constants have been extracted from the spectra. RP FRUM, CI (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 22 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP L61 EP L64 DI 10.1086/186831 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY811 UT WOS:A1993KY81100016 ER PT J AU KIMBLE, RA DAVIDSEN, AF LONG, KS FELDMAN, PD AF KIMBLE, RA DAVIDSEN, AF LONG, KS FELDMAN, PD TI EXTREME ULTRAVIOLET OBSERVATIONS OF HZ 43 AND THE LOCAL H/HE RATIO WITH THE HOPKINS ULTRAVIOLET TELESCOPE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, ABUNDANCES; SOLAR NEIGHBORHOOD; STARS, INDIVIDUAL, HZ 43; ULTRAVIOLET, INTERSTELLAR; ULTRAVIOLET, STARS; WHITE DWARFS ID DA WHITE-DWARFS; INTERSTELLAR-MEDIUM; SPECTRUM; HZ-43; IONIZATION; EXOSAT AB We present a spectrum of the hot DA white dwarf HZ 43 in the EUV, near the 504 A ionization edge of neutral helium, obtained with the Hopkins Ultraviolet Telescope (HUT) during the 1990 December Astro-1 mission. The interstellar column densities derived from this spectrum (N(H) = 6.5 +/- 0.5 x 10(17) cm-2; N(He) = 6.6 +/- 1.4 x 10(16) cm-2) rule out the anomalous interstellar absorption model proposed by Heise et al., which required a greater column density of neutral helium than neutral hydrogen toward HZ 43 in order to explain the low EUV flux from HZ 43 reported by EXOSAT. Instead, we find the interstellar neutral H/He ratio toward HZ 43 to be consistent with the canonical cosmic abundance ratio of 10 or with the 11.6 +/- 1.0 ratio measured by HUT along the line of sight toward another DA white dwarf, G191-B2B. The HUT observations suggest that either there is a substantial calibration error in the EXOSAT spectroscopy of HZ 43, or otherwise undetected metals in the nominally pure hydrogen HZ 43 atmosphere suppress its flux between 150 and 300 angstrom, or both. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP KIMBLE, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 24 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP L41 EP L44 DI 10.1086/186826 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY811 UT WOS:A1993KY81100011 ER PT J AU LANGER, WD WILSON, RW ANDERSON, CH AF LANGER, WD WILSON, RW ANDERSON, CH TI HIERARCHICAL STRUCTURE-ANALYSIS OF INTERSTELLAR CLOUDS USING NONORTHOGONAL WAVELETS SO ASTROPHYSICAL JOURNAL LA English DT Article DE METHODS, DATA ANALYSIS; ISM, MOLECULES; ISM, INDIVIDUAL, BARNARD-5 (B5) ID MOLECULAR CLOUDS; TURBULENCE; GALAXY AB We introduce the use of Laplacian pyramid transforms, a form of nonorthogonal wavelets, to analyze the structure of interstellar clouds. These transforms are generally better suited for analyzing structure than orthogonal wavelets because they provide more flexibility in the structure of the encoding functions-here circularly symmetric bandpass filters. This technique is applied to CO maps of Barnard 5. In the (CO)-C-13 maps, for example, we identify 60 different fragments and clumps, as well as several cavities, or bubbles. Many features show evidence of hierarchical structure, with most of the power in the largest wavelengths. The clumps have a more chaotic structure at small wavelengths than expected for Kolmogorov turbulence, and a mass distribution proportional to M-5/3. The structure analysis is consistent with a picture where gravity, energy injection, compressible turbulence, and coalescence play an important role in the dynamics of B5. C1 AT&T BELL LABS,HOLMDEL,NJ 07733. WASHINGTON UNIV,SCH MED,ST LOUIS,MO 63110. RP LANGER, WD (reprint author), JET PROP LAB,MS 169-506,PASADENA,CA 91109, USA. NR 23 TC 34 Z9 34 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1993 VL 408 IS 1 BP L45 EP & DI 10.1086/186827 PN 2 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY811 UT WOS:A1993KY81100012 ER PT J AU NORBURY, JW TOWNSEND, LW AF NORBURY, JW TOWNSEND, LW TI CROSS-SECTION PARAMETERIZATIONS FOR COSMIC-RAY NUCLEI .1. SINGLE NUCLEON REMOVAL SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ATOMIC PROCESSES; COSMIC RAYS ID ELECTRIC QUADRUPOLE EXCITATIONS; HEAVY-ION COLLISIONS; ELECTROMAGNETIC DISSOCIATION; RELATIVISTIC NUCLEI; HIGH-ENERGY; CARBON TARGETS; ASTROPHYSICAL APPLICATIONS; COULOMB DISSOCIATION; AU-197 TARGETS; HYDROGEN AB Parameterizations of single nucleon removal from the electromagnetic and strong interactions of cosmic rays with nuclei are presented. These parameterizations are based upon the theoretical models developed by Baur, Bertulani, Benesh, Cook, Vary, Norbury, and Townsend. They should be very suitable for use in cosmic-ray propagation through interstellar space, Earth's atmosphere, lunar samples, meteorites, spacecraft walls, and lunar and martian habitats. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP NORBURY, JW (reprint author), UNIV WISCONSIN,DEPT PHYS,LA CROSSE,WI 54601, USA. NR 64 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 1993 VL 86 IS 1 BP 307 EP 312 DI 10.1086/191780 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY871 UT WOS:A1993KY87100011 PM 11537677 ER PT J AU HEWAGAMA, T DEMING, D JENNINGS, DE OSHEROVICH, V WIEDEMANN, G ZIPOY, D MICKEY, DL GARCIA, H AF HEWAGAMA, T DEMING, D JENNINGS, DE OSHEROVICH, V WIEDEMANN, G ZIPOY, D MICKEY, DL GARCIA, H TI SOLAR MAGNETIC-FIELD STUDIES USING THE 12-MICRON EMISSION-LINES .2. STOKES PROFILES AND VECTOR FIELD SAMPLES IN SUNSPOTS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE INFRARED, SOLAR SYSTEM; INSTRUMENTATION, INTERFEROMETERS; POLARIZATION; SUN, MAGNETIC FIELDS ID MG-I; UNIPOLAR SUNSPOT; ACTIVE REGIONS; FINE-STRUCTURE; 12 MICRONS; POLARIMETER; SPECTRUM; FEATURES; MODELS; TOWER AB This paper reports a polarimetric study of the extremely Zeeman-sensitive 12.32 mum neutral magnesium (Mg I) emission line from sunspots. A single blocked impurity band (BIB) detector in a cryogenic grating postdisperser was used to limit the McMath Fourier transform spectrometer (FTS) bandpass and obtain high signal/noise spectra at 0.005 cm-1 spectral resolution with 4.5'' spatial resolution. A polarization analyzer preceded the FTS and consisted of an antireflection coated CdS 1/4 waveplate, a thin film Ge linear polarizer, and a second 1/4 waveplate. The instrument polarization introduced by the McMath telescope is shown to be negligible for the purpose of 12 mum polarimetry. Stokes I, Q, U, V profiles were generated, with a time resolution of 12 minutes, by subtracting successive interferograms. Within the sunspot the Zeeman triplet was fully resolved. Vector fields were derived by nonlinear least squares fits of the Seares formulae to the observed Stokes profiles. The adequacy of the fit procedure was established by comparison to complete Stokes radiative transfer calculations, based on recent NLTE line formation results for the 12.32 mum transition. The visually symmetric sunspot in the region NOAA/USAF group 5754 was observed over the period 1989 October 23-28 and the complex sunspot region NOAA/USAF group 5014 over the period 1988 May 10-15. The 5754 sunspot field strength varied from 2050 G in the umbra to 650 G at the outer penumbral edge, with the field extending well beyond the photometric boundary of the sunspot. Vector magnetograms obtained by the Haleakala Stokes polarimeter, operating at 6302.5 angstrom, show an umbral field strength which is larger by 400 G. The magnetic data indicate the height of formation for the Mg I line to be approximately 600 km above tau = 1 for the 6302.5 angstrom line. Unusual penumbral field inclinations are seen in the 12 mum data, and these may represent the magnetic signatures of X-ray loops which have recently been observed to originate in the penumbra. The ratio of the polarized 12 mum emission (Q2 + U2 + V2)1/2 to the total intensity (I) is found to be unity within the umbra and most of the penumbra, decreasing to 0.9 at the outer edge of the penumbra. This implies that the sunspot magnetic field at the 12 mum height is not filamentary in the sense of containing field-free regions, nor is there cancellation of field over any spatial scale in the beam area. We reiterate our previous conclusion that the widths of the 12 mum sigma-components are caused by spatially unresolved magnetic field strength variations of order +/-250 G. C1 UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. NOAA, SPACE ENVIRONM LAB, BOULDER, CO 80303 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP UNIV MARYLAND, ASTRON PROGRAM, COLL PK, MD 20740 USA. RI Hewagama, T/C-8488-2012; Jennings, Donald/D-7978-2012 NR 82 TC 25 Z9 25 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 1993 VL 86 IS 1 BP 313 EP 332 DI 10.1086/191781 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KY871 UT WOS:A1993KY87100012 ER PT J AU BHATIA, AK KASTNER, SO AF BHATIA, AK KASTNER, SO TI COLLISION STRENGTHS AND TRANSITION RATES FOR 0-III SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID ELECTRON-IMPACT EXCITATION; O-III; FORBIDDEN TRANSITIONS; OSCILLATOR-STRENGTHS; CROSS-SECTIONS; LINES C1 MATH SCI CONSULTANTS INC,GREENBELT,MD 20770. RP BHATIA, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON BRANCH,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 19 TC 25 Z9 25 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAY PY 1993 VL 54 IS 1 BP 133 EP 164 DI 10.1006/adnd.1993.1011 PG 32 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA LE348 UT WOS:A1993LE34800004 ER PT J AU KYLE, HL HICKEY, JR ARDANUY, PE JACOBOWITZ, H ARKING, A CAMPBELL, GG HOUSE, FB MASCHHOFF, R SMITH, GL STOWE, LL VONDERHAAR, T AF KYLE, HL HICKEY, JR ARDANUY, PE JACOBOWITZ, H ARKING, A CAMPBELL, GG HOUSE, FB MASCHHOFF, R SMITH, GL STOWE, LL VONDERHAAR, T TI THE NIMBUS EARTH RADIATION BUDGET (ERB) EXPERIMENT - 1975 TO 1992 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID OUTGOING LONGWAVE RADIATION; VIEW RADIOMETER MEASUREMENTS; CONSTANT SECULAR CHANGES; SOLAR TOTAL IRRADIANCE; WIDE-FIELD; DATA SET; EL-NINO; CALIBRATION ADJUSTMENT; INTERANNUAL VARIATIONS; R-MODES AB Three spectrally broadband measurement sets are presently being used for earth radiation budget (ERB) studies. These are the Nimbus-6 ERB (July 1975 to June 1978), the Nimbus-7 ERB (November 1978 to the present), and the Earth Radiation Budget Experiment (ERBE) (November 1984 to present). The measurements yield the incident solar irradiance, absorbed solar energy, outgoing longwave and net radiation. The Nimbus-7 started an accurate record of the solar constant in November 1978, while a nearly continuous record of the earth's radiation budget began in July 1975 with the Nimbus-6. Both the Nimbus-6 and -7 products have, in recent years, been reprocessed with improved processing and calibration algorithms so that the entire dataset can be considered as new. However, because of the use of different calibration and processing procedures, the three datasets for some purposes must be considered as piecewise continuous. Nevertheless, the data have been used in many important climate studies. The Nimbus-7 solar measurements indicate that the sun is a low-level variable star and that the mean annual solar energy just outside the earth's atmosphere was about 0.1% lower in 1984 than in 1979 and 1991. Further, the 9 years of Nimbus-7 ERB measurements show the earth's mean annual energy budget to be stable at the 0.2% level with apparently real changes in the annual emitted longwave at the 0.1% to 0.2% level that are associated with changes in the surface temperature. Other studies deal with the cooling and warming effects of clouds, interregional energy transport, and interannual variations. Our understanding of the sensors and how to derive an accurate mean radiation budget from the measurements has slowly improved over the years. But to date, there has been no consensus on the use of consistent calibration and processing procedures to permit quantitatively consistent analyses across the Nimbus-6, -7, and ERBE products. This report describes some successes and lessons learned during the Nimbus ERB program and the compatibility of the Nimbus and ERBE products. C1 EPPLEY LAB INC,NEWPORT,RI. RES & DATA SYST CORP,GREENBELT,MD. GULTON IND INC,ALBUQUERQUE,NM. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,WASHINGTON,DC 20233. COLORADO STATE UNIV,FT COLLINS,CO 80523. DREXEL UNIV,PHILADELPHIA,PA 19104. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP KYLE, HL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Vonder Haar, Thomas/F-2048-2011; vonderhaar, thomas/N-6724-2015 OI vonderhaar, thomas/0000-0002-1962-7757 NR 99 TC 36 Z9 36 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1993 VL 74 IS 5 BP 815 EP 830 DI 10.1175/1520-0477(1993)074<0815:TNERBE>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LD116 UT WOS:A1993LD11600005 ER PT J AU WANG, SY LUM, JL CARLS, MG RICE, SD AF WANG, SY LUM, JL CARLS, MG RICE, SD TI RELATIONSHIP BETWEEN GROWTH AND TOTAL NUCLEIC-ACIDS IN JUVENILE PINK SALMON, ONCORHYNCHUS-GORBUSCHA, FED CRUDE-OIL CONTAMINATED FOOD SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID RNA-DNA RATIOS; GAIRDNERI RICHARDSON; ENZYME-ACTIVITIES; ATLANTIC COD; GADUS-MORHUA; FISH; DEPRIVATION; STARVATION; SALINITY; LARVAE AB Total nucleic acids of juvenile pink salmon, oncorhynchus gorbuscha, fed crude oil contaminated food were analyzed to determine if nucleic acid measurements can be used to evaluate growth of fish collected at oil spill sites. In general, the nucleic acid concentration (micrograms per milligram dry weight) of salmon fry fed food contaminated with either 0.37 or 2.78 mg crude oil/g food was not significantly affected. However, RNA concentration of fry fed food contaminated with 34.83 mg/g was reduced whereas DNA concentration increased. Results over 8 wk indicate decreased protein synthesis and cell content but maintenance of cell integrity in these fish. Growth was inversely related to the level of crude oil contamination in the food. The significant correlations between measured growth and RNA/DNA ratios and RNA contents (micrograms RNA per millimetre fork length) suggest that nucleic acid measurements can be used to compare growth of fish collected from the field. C1 NOAA,NATL MARINE FISHERIES SERV,AUKE BAY LAB,JUNEAU,AK 99801. RP WANG, SY (reprint author), UNIV SO MISSISSIPPI,DEPT BIOL SCI,HATTIESBURG,MS 39406, USA. NR 23 TC 22 Z9 23 U1 0 U2 10 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAY PY 1993 VL 50 IS 5 BP 996 EP 1001 DI 10.1139/f93-115 PG 6 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA LR758 UT WOS:A1993LR75800014 ER PT J AU LAU, YT AF LAU, YT TI GLOBAL ASPECTS OF HOMOCLINIC BIFURCATIONS OF 3-DIMENSIONAL SADDLES SO CHAOS SOLITONS & FRACTALS LA English DT Article ID STABLE MANIFOLDS; LORENZ SYSTEM; ORBITS; SYMMETRY; FLOWS; NULLS AB We use the manifold approach to study the homoclinic bifurcations of a saddle fixed point in three-dimensional flows. With the introduction of time delay functions and symbolic rules on manifolds, we construct complete three-dimensional pictures of the invariant manifolds for the global flows. RP LAU, YT (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,MAIL CODE 9301,GREENBELT,MD 20771, USA. NR 26 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD MAY-JUN PY 1993 VL 3 IS 3 BP 369 EP 382 DI 10.1016/0960-0779(93)90019-W PG 14 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA LF477 UT WOS:A1993LF47700010 ER PT J AU BERTHIAS, JP SHAHIDSALESS, B AF BERTHIAS, JP SHAHIDSALESS, B TI TORSION AND NON-METRICITY IN SCALAR TENSOR THEORIES OF GRAVITY SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article ID DICKE-TYPE MODELS; 1ST-ORDER FORMALISM; SUPERSTRING THEORY; TIME AB We show that the gravitational field equations derived from an action composed of (i) an arbitrary function of the scalar curvature and other scalar fields plus (ii) connection-independent kinetic and source terms, are identical whether one chooses non-metricity to vanish and have non-zero torsion or vice versa. RP BERTHIAS, JP (reprint author), JET PROP LAB,301150,PASADENA,CA 91109, USA. NR 19 TC 14 Z9 14 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD MAY PY 1993 VL 10 IS 5 BP 1039 EP 1044 DI 10.1088/0264-9381/10/5/020 PG 6 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA LF005 UT WOS:A1993LF00500020 ER PT J AU STEINBERG, TA WILSON, DB BENZ, F AF STEINBERG, TA WILSON, DB BENZ, F TI THE COMBUSTION PHASE OF BURNING METALS - RESPONSE SO COMBUSTION AND FLAME LA English DT Note C1 NASA,WHITE SANDS TEST FACIL,LAS CRUCES,NM. RP STEINBERG, TA (reprint author), LOCKHEED ESC,WHITE SANDS TEST FACIL,LAS CRUCES,NM, USA. OI Steinberg, Theodore/0000-0002-9270-4130 NR 14 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1993 VL 93 IS 3 BP 343 EP 347 DI 10.1016/0010-2180(93)90116-K PG 5 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA KY523 UT WOS:A1993KY52300014 ER PT J AU LEBEAU, GJ RAY, SE ALIABADI, SK TEZDUYAR, TE AF LEBEAU, GJ RAY, SE ALIABADI, SK TEZDUYAR, TE TI SUPG FINITE-ELEMENT COMPUTATION OF COMPRESSIBLE FLOWS WITH THE ENTROPY AND CONSERVATION VARIABLES FORMULATIONS SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID ADVECTIVE-DIFFUSIVE SYSTEMS; FLUID-DYNAMICS; EQUATIONS; OPERATOR; EULER AB SUPG-stabilized finite element formulations of compressible Euler equations based on the conservation and entropy variables are investigated and compared. The formulation based on the conservation variables consists of the formulation introduced by Tezduyar and Hughes plus a shock capturing term. The formulation based on the entropy variables is the same as the one by Hughes, Franca and Mallet, which has a shock capturing term built in. These formulations are tested on several subsonic, transonic and supersonic compressible flow problems. It is shown that the stabilized formulation based on the conservation variables gives solutions which are just as good as those obtained with the entropy variables. Furthermore, the solutions obtained using the two formulations are very close and in some cases almost indistinguishable. Consequently, it can be deduced that the relative mer-its of these two formulations will continue to remain under debate. C1 UNIV MINNESOTA,MINNESOTA SUPERCOMP INST,1200 WASHINGTON AVE S,MINNEAPOLIS,MN 55415. UNIV MINNESOTA,USA,HIGH PERFORMANCE COMP RES CTR,DEPT AEROSP ENGN & MECH,MINNEAPOLIS,MN 55415. NASA,LYNDON B JOHNSON SPACE CTR,DIV NAVIGAT CONTROL & AERONAUT,COMP FLUID DYNAM GRP,HOUSTON,TX 77058. RI Tezduyar, Tayfun/F-6134-2012 OI Tezduyar, Tayfun/0000-0001-8707-3162 NR 13 TC 77 Z9 77 U1 1 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD MAY PY 1993 VL 104 IS 3 BP 397 EP 422 DI 10.1016/0045-7825(93)90033-T PG 26 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA LC132 UT WOS:A1993LC13200006 ER PT J AU FABRIS, G BACK, L AF FABRIS, G BACK, L TI PREDICTION OF PERFORMANCE OF 2-PHASE FLOW NOZZLE AND LIQUID-METAL MAGNETOHYDRODYNAMIC (LMMHD) GENERATOR FOR NO SLIP CONDITION SO ENERGY CONVERSION AND MANAGEMENT LA English DT Article AB Two-phase LMMHD energy conversion systems have potentially significant advantages over conventional systems, such as higher thermal efficiency and substantial simplicity with lower capital and maintenance costs. Maintenance of low velocity slip is of importance for achieving high generator efficiency. A bubbly flow pattern ensures very low velocity slip. The full governing equations have been written, and a computer prediction code has been developed to analyze the performance of a two-phase flow LMMHD generator and nozzle under conditions of no slip. Three different shapes of LMMHD generator have been investigated. Electrical power outputs are in the 20 kW range. Generator efficiency exceeds 71% at an average void fraction of about 70%. This is an appreciable performance for a short generator without insulating vanes for minimizing electrical losses in the end regions. RP FABRIS, G (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0196-8904 J9 ENERG CONVERS MANAGE JI Energy Conv. Manag. PD MAY PY 1993 VL 34 IS 5 BP 373 EP 383 DI 10.1016/0196-8904(93)90088-R PG 11 WC Thermodynamics; Energy & Fuels; Mechanics SC Thermodynamics; Energy & Fuels; Mechanics GA KN727 UT WOS:A1993KN72700004 ER PT J AU SOGARD, SM OLLA, BL AF SOGARD, SM OLLA, BL TI THE INFLUENCE OF PREDATOR PRESENCE ON UTILIZATION OF ARTIFICIAL SEAGRASS HABITATS BY JUVENILE WALLEYE POLLOCK, THERAGRA-CHALCOGRAMMA SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE PREDATION REFUGE; HABITAT STRUCTURE; HABITAT SELECTION; FISH BEHAVIOR ID DECAPOD CRUSTACEANS; PREY RELATIONSHIPS; EELGRASS; FISHES; COLONIZATION; VEGETATION; ABUNDANCE; PATTERNS; MEADOWS; SEA AB Behavioral preference for a structured habitat (artificial seagrass) by juvenile walleye pollock, Theragra chalcogramma, was tested in controlled laboratory experiments. We monitored position of fish in 2000 1 tanks with and without artificial seagrass present in one half of the tank. In addition, we exposed walleye pollock to a predator model, assessing their response when a grass plot was available or unavailable as a potential refuge. In the absence of predators, the fish avoided the artificial seagrass, displaying a preference for the open water side of the experimental tanks. In the presence of a predator model, however, juvenile walleye pollock readily entered the artificial seagrass plots. In addition, they often remained in the grass canopy in proximity to the predator instead of moving out of the grass to avoid the predator (when no grass was present they consistently moved to the opposite side of the tank from the predator). The behavioral choices exhibited in this study suggest that juvenile walleye pollock modify habitat selection in response to perceived predation risk, and recognize the structure provided by artificial seagrass as a potential refuge. RP SOGARD, SM (reprint author), NATL MARINE FISHERIES SERV,HATFIELD MARINE SCI CTR,ALASKA FISHERIES SCI CTR,NEWPORT,OR 97365, USA. NR 19 TC 49 Z9 49 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAY PY 1993 VL 37 IS 1 BP 57 EP 65 DI 10.1007/BF00000712 PG 9 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA LB200 UT WOS:A1993LB20000006 ER PT J AU CUTLER, AD BRADSHAW, P AF CUTLER, AD BRADSHAW, P TI STRONG VORTEX BOUNDARY-LAYER INTERACTIONS .2. VORTICES LOW SO EXPERIMENTS IN FLUIDS LA English DT Article ID WALL AB This is the second of two papers on the interaction between a longitudinal vortex pair, produced by a delta-wing at angle of attack, and a turbulent boundary layer developing on a flat plate. In the first paper only the outer parts of the vortices entered the boundary layer whereas in this paper the vortices merge with it. In the resultant interaction, the boundary layer between the vortices is kept thin by lateral divergence and a three-dimensional separation fine is formed outboard of each vortex. Turbulent, momentum-deficient fluid containing longitudinal vorticity is entrained from the boundary layer along these lines and wrapped around the vortices. As a consequence, the turbulent region of the vortices increases in size and the circulation slowly decreases. It is shown that the flow near the separation line and in the vortices is complicated, and this interaction is expected to be more difficult to calculate than the first. Detailed mean flow and turbulence measurements are reported. C1 STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. RP CUTLER, AD (reprint author), GEORGE WASHINGTON UNIV,JIAFS,NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 14 TC 12 Z9 12 U1 1 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD MAY PY 1993 VL 14 IS 6 BP 393 EP 401 PG 9 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA LF049 UT WOS:A1993LF04900001 ER PT J AU BOGARD, D NYQUIST, L TAKEDA, H MORI, H AOYAMA, T BANSAL, B WIESMANN, H SHIH, CY AF BOGARD, D NYQUIST, L TAKEDA, H MORI, H AOYAMA, T BANSAL, B WIESMANN, H SHIH, CY TI ANTARCTIC POLYMICT EUCRITE YAMATO-792769 AND THE CRATERING RECORD ON THE HED PARENT BODY SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID IMBRIUM BASIN; RB-SR; SM; ROCKS; CLAST; CRUST; MOON; AGES AB Yamato Y792769 is a polymict breccia containing pyroxenes of a limited range in chemical comPositions. Compared to most other Yamato polymict eucrites, Y792769 includes fewer and smaller eucritic clasts with homogenized pyroxenes. Its fine-grained matrix is shock-compacted and sintered. The time of the last thermal event, which produced this texture and formed the breccia, is determined by the well-defined Ar-39-Ar-40 age of 3.99 +/- 0.04 Ga. The complete resetting of the Ar-39-Ar-40 age is consistent with the texture of Y792769, as viewed in the transmission electron microscope (TEM), which suggests shock compaction converted part of the matrix plagioclase to maskelynite. Sm-Nd data define an apparent isochron corresponding to an age of 4.23 +/- 0.12 Ga. This apparent age probably reflects partial resetting of the Sm-Nd system during breccia formation, but similar ages recorded in the highest-temperature argon releases and in the Rb-Sr model age of relict plagioclases lend some support to its reality. Sm-Nd data for relict pyroxenes fall on a 4.56-Ga Sm-Nd reference isochron and on or above a 4.56-Ga Rb-Sr reference isochron, suggesting slight loss of rubidium during breccia formation. The pyroxene data are most suggestive of a ''conventional'' approximately 4.56 Ga age for the protolith rocks. The approximately 3.99 Ga Ar-39-Ar-40 age predates the accepted age of formation of the lunar Imbrium and Serenitatis basins but probably reflects a period of intense meteoroid bombardment that affected the entire inner solar system. C1 UNIV TOKYO,FAC SCI,INST MINERAL,TOKYO 113,JAPAN. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77258. RP BOGARD, D (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 27 TC 7 Z9 7 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1993 VL 57 IS 9 BP 2111 EP 2121 DI 10.1016/0016-7037(93)90097-G PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LC554 UT WOS:A1993LC55400015 ER PT J AU JUREWICZ, AJG MITTLEFEHLDT, DW JONES, JH AF JUREWICZ, AJG MITTLEFEHLDT, DW JONES, JH TI EXPERIMENTAL PARTIAL MELTING OF THE ALLENDE (CV) AND MURCHISON (CM) CHONDRITES AND THE ORIGIN OF ASTEROIDAL BASALTS SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID EUCRITE PARENT BODY; ANGRA-DOS-REIS; METEORITES; OLIVINE; TEMPERATURE; ACHONDRITE; EQUILIBRIA; PHOSPHORUS; ELEMENTS; EARTH AB The compositions of experimental partial melts from the Allende (CV) and anhydrous Murchison (CM) chondrites depend strongly on ambient oxygen fugacity (f(O2). At low f(O2) (IW-1) partial melts are tholeiitic and resemble the compositions of eucrites, whereas at high f(O2) (IW+2) melts are silica undersaturated and resemble the compositions of angrites. In particular, the major element composition of our (1170-degrees-C, IW-1) melt of Murchison is strikingly similar to natural eucrites. Allende partial melts, while broadly eucritic, do not match most eucrites in detail. Conversely, IW+2 Allende partial melts are more like angrite compositions than are partial melts of Murchison. Chromium contents of eucrites and of our spinel-saturated Murchison and Allende experiments are extremely similar, suggesting that eucrites are also spinel saturated. This observation favors a partial melting origin for eucrites such as Sioux County, as opposed to an origin by fractional crystallization. However, most of the main group eucrites have slightly lower Mg#'s and slightly higher CaO/Al2O3 ratios than Sioux County, suggesting that, relative to Sioux County, the majority of the main group eucrites either have experienced small amounts of fractional crystallization or were produced by slightly smaller amounts of partial melting. If the eucrites were produced by simple partial melting, the MnO content of the eucrite parent body must be rather high compared to either Allende or Murchison. In contrast to comparisons between our IW-1 experiments and eucrites, none of our IW+2 experiments have exactly reproduced a natural angrite composition. There are also minor but significant discrepancies between our partial melting experiments and experiments on angrite compositions. While these differences may, in part, be due to our poor knowledge of the angrite parent body, they may be explicable if at least some of the angrites are not primitive partial melts but, rather, impact melts. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP JUREWICZ, AJG (reprint author), LOCKHEED ENGN & SCI CO,MAIL CODE C23,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 45 TC 90 Z9 90 U1 2 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 1993 VL 57 IS 9 BP 2123 EP 2139 DI 10.1016/0016-7037(93)90098-H PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LC554 UT WOS:A1993LC55400016 ER PT J AU LAUNIUS, RD AF LAUNIUS, RD TI UNITED-STATES MILITARY USES OF SPACE, 1945-1991 - RICHELSON,J SO GOVERNMENT PUBLICATIONS REVIEW LA English DT Book Review RP LAUNIUS, RD (reprint author), NASA,OFF ADMINISTRATOR,WASHINGTON,DC 20546, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0277-9390 J9 GOV PUBL REV PD MAY-JUN PY 1993 VL 20 IS 3 BP 361 EP 363 DI 10.1016/0277-9390(93)90007-C PG 3 WC Information Science & Library Science SC Information Science & Library Science GA LG089 UT WOS:A1993LG08900007 ER PT J AU POTE, KG ROSS, MD AF POTE, KG ROSS, MD TI UTRICULAR OTOCONIA OF SOME AMPHIBIANS HAVE CALCITIC MORPHOLOGY SO HEARING RESEARCH LA English DT Article DE INNER EAR; VESTIBULAR SYSTEM; SCANNING ELECTRON MICROSCOPY; OTOCONIA; CALCITE; AMPHIBIANS ID INNER-EAR; RAT; MICROSCOPY; STATOCONIA; CHICK AB This report concerns the morphological features of otoconia removed from the inner ear of four amphibian species. Results from scanning electron microscopic examination are compared based on the site of origin. These results show that utricular otoconia have a mineral structure that mimics calcite, rather than the widely accepted idea that they are mineralized by calcium carbonate of the aragonite polymorph. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP POTE, KG (reprint author), HARVARD UNIV,CHILDRENS HOSP,SCH MED,DEPT OTOLARYNGOL & COMMUN DISORDERS,300 LONGWOOD AVE,BOSTON,MA 02115, USA. NR 37 TC 18 Z9 18 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-5955 J9 HEARING RES JI Hear. Res. PD MAY PY 1993 VL 67 IS 1-2 BP 189 EP 197 DI 10.1016/0378-5955(93)90246-W PG 9 WC Audiology & Speech-Language Pathology; Neurosciences; Otorhinolaryngology SC Audiology & Speech-Language Pathology; Neurosciences & Neurology; Otorhinolaryngology GA LH027 UT WOS:A1993LH02700021 PM 8340270 ER PT J AU POLLACK, JB DALTON, JB GRINSPOON, D WATTSON, RB FREEDMAN, R CRISP, D ALLEN, DA BEZARD, B DEBERGH, C GIVER, LP MA, Q TIPPING, R AF POLLACK, JB DALTON, JB GRINSPOON, D WATTSON, RB FREEDMAN, R CRISP, D ALLEN, DA BEZARD, B DEBERGH, C GIVER, LP MA, Q TIPPING, R TI NEAR-INFRARED LIGHT FROM VENUS NIGHTSIDE - A SPECTROSCOPIC ANALYSIS SO ICARUS LA English DT Article ID DARK SIDE; STATISTICAL-THEORY; CARBONYL SULFIDE; ROTATIONAL BANDS; WATER CONTINUUM; HEATING RATES; SULFURIC-ACID; ENERGY-LEVELS; SPECTRA; INTENSITIES C1 SYNERNET,FREMONT,CA. UNIV COLORADO,BOULDER,CO 80309. VISIDYNE INC,BURLINGTON,MA 01803. STERLING INC,PALO ALTO,CA. JET PROP LAB,PASADENA,CA 91109. ANGLO AUSTRALIAN OBSERV,EPPING,NSW 2121,AUSTRALIA. OBSERV PARIS,F-92195 MEUDON,FRANCE. NASA,GISS,NEW YORK,NY 10025. UNIV ALABAMA,TUSCALOOSA,AL 35487. RP POLLACK, JB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 91 TC 199 Z9 203 U1 0 U2 8 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 1993 VL 103 IS 1 BP 1 EP 42 DI 10.1006/icar.1993.1055 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LH114 UT WOS:A1993LH11400001 ER PT J AU SHOWALTER, MR CUZZI, JN AF SHOWALTER, MR CUZZI, JN TI SEEING GHOSTS - PHOTOMETRY OF SATURNS G-RING SO ICARUS LA English DT Article ID PLASMA-WAVE INSTRUMENT; PARTICLE IMPACTS; PLANETARY RINGS; JUPITERS RING; F-RING; SYSTEM; VOYAGER-2; SATELLITES; ORIGIN; MODEL C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP SHOWALTER, MR (reprint author), STANFORD UNIV,CTR RADAR ASTRON,223 DURAND BLDG,STANFORD,CA 94305, USA. NR 55 TC 59 Z9 59 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 1993 VL 103 IS 1 BP 124 EP 143 DI 10.1006/icar.1993.1062 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LH114 UT WOS:A1993LH11400008 ER PT J AU IANNELLI, JM SHEVY, Y KITCHING, J YARIV, A AF IANNELLI, JM SHEVY, Y KITCHING, J YARIV, A TI LINEWIDTH REDUCTION AND FREQUENCY STABILIZATION OF SEMICONDUCTOR-LASERS USING DISPERSIVE LOSSES IN AN ATOMIC VAPOR SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID EXTERNAL OPTICAL FEEDBACK; MODE INJECTION-LASER; NOISE; PHASE AB The effects of a dispersive loss on the linewidth and chirp of a semiconductor laser are discussed. A van der Pol analysis is used to obtain expressions for linewidth reduction and chirp reduction in an arbitrary optical feedback configuration. Specifically the use of an atomic cesium vapor as a dispersive loss mechanism is considered. The dominant factor in reducing the linewidth and chirp is shown to be the frequency-dependent phase change from the atomic vapor. However, we also show that under certain operating conditions the frequency-dependent amplitude changes from the atomic vapor also contribute to the reduction. The results are shown to be in agreement with a detailed rate equation calculation. RP CALTECH, JET PROPULS LAB, PASADENA, CA 91125 USA. NR 17 TC 8 Z9 8 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9197 EI 1558-1713 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAY PY 1993 VL 29 IS 5 BP 1253 EP 1261 DI 10.1109/3.236139 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA LL311 UT WOS:A1993LL31100002 ER PT J AU PENG, J BALANIS, CA BARBER, GC AF PENG, J BALANIS, CA BARBER, GC TI NEC AND ESP CODES - GUIDELINES, LIMITATIONS, AND EMC APPLICATIONS SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article AB This article addresses the computer modeling and simulation of EMC problems of complex structures, using the NEC and ESP moment method codes. The rules and guidelines of modeling using the two codes are summarized. In addition, visualization and automation of the modeling process are made possible through an interface computer program GEOM developed at Arizona State University. Finally, the interference between two wire antennas mounted on a complex helicopter model is given as an example of using these codes in EMC applications. C1 NASA,LANGLEY RES CTR,JOINT RES PROGRAMS OFF,AVRADA,HAMPTON,VA 23601. RP PENG, J (reprint author), ARIZONA STATE UNIV,TELECOMMUN RES CTR,DEPT ELECT ENGN,TEMPE,AZ 85287, USA. NR 12 TC 5 Z9 6 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD MAY PY 1993 VL 35 IS 2 BP 124 EP 133 DI 10.1109/15.229428 PN 1 PG 10 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA LG950 UT WOS:A1993LG95000003 ER PT J AU TIRKAS, PA BALANIS, CA PURCHINE, MP BARBER, GC AF TIRKAS, PA BALANIS, CA PURCHINE, MP BARBER, GC TI FINITE-DIFFERENCE TIME-DOMAIN METHOD FOR ELECTROMAGNETIC-RADIATION, INTERFERENCE, AND INTERACTION WITH COMPLEX STRUCTURES SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article ID ABSORBING BOUNDARY-CONDITIONS; SCATTERING PROBLEMS; MAXWELL EQUATIONS; WAVE-EQUATION; DIELECTRIC STRUCTURES; NUMERICAL-SOLUTION; NARROW APERTURES; FDTD ALGORITHM; HYPERTHERMIA; PENETRATION AB In this paper the finite-difference time-domain (FDTD) method is reviewed and then used to model and predict the radiation patterns of a monopole antenna mounted on the bottom of a perfectly conducting helicopter structure. The computed radiation patterns are compared with measurements demonstrating the accuracy of the FDTD method. To study the effect of antenna interference, a second monopole antenna is mounted on the structure and the patterns are recalculated. The perfectly conducting helicopter model is then replaced by a partially composite/partially conducting material structure and the electromagnetic fields penetrating the structure from an incident plane wave are analyzed. A preprocessing geometry program used in generating an FDTD geometry model by using a solid surface helicopter structure is presented. C1 NASA,LANGLEY RES CTR,AVRADA JOINT RES PROGRAMS OFF,HAMPTON,VA 23681. UNIV KANSAS,REMOTE SENSING & RADAR SYST LAB,LAWRENCE,KS 66045. RP TIRKAS, PA (reprint author), ARIZONA STATE UNIV,TELECOMMUN RES CTR,DEPT ELECT ENGN,TEMPE,AZ 85287, USA. NR 54 TC 22 Z9 22 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD MAY PY 1993 VL 35 IS 2 BP 192 EP 203 DI 10.1109/15.229421 PN 1 PG 12 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA LG950 UT WOS:A1993LG95000010 ER PT J AU BAKER, DN MASON, GM FIGUEROA, O COLON, G WATZIN, JG ALEMAN, RM AF BAKER, DN MASON, GM FIGUEROA, O COLON, G WATZIN, JG ALEMAN, RM TI AN OVERVIEW OF THE SOLAR, ANOMALOUS, AND MAGNETOSPHERIC PARTICLE EXPLORER (SAMPEX) MISSION SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID COSMIC-RAYS AB The scientific objective of the NASA Small-class Explorer Mission SAMPEX are summarized. A brief history of the Small Explorer program is provided along with a description of the SAMPEX project development and structure. The spacecraft and scientific instrument configuration is presented. The orbit of SAMPEX has an altitude of 520 by 670 km and an 82-degrees inclination. Maximum possible power is provided by articulated solar arrays that point continuously toward the sun. Highly sensitive science instruments point generally toward the local zenith, especially over the terrestrial poles, in order to measure optimally the galactic and solar cosmic ray flux. Energetic magnetospheric particle precipitation is monitored at lower geomagnetic latitudes. The spacecraft uses several innovative approaches including an optical fiber bus, powerful onboard computers, and large solid state memories (instead of tape recorders). Spacecraft communication and data acquisition are discussed and the space- and ground-segment data flows are summarized. A mission lifetime of 3 years is sought with the goal of extending data acquisition over an even longer portion of the 11-year solar activity cycle. C1 NASA,GODDARD SPACE FLIGHT CTR,ENGN DIRECTORATE,GREENBELT,MD 20771. UNIV MARYLAND,DEPT PHYS,COLL PK,MD 20742. UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLL PK,MD 20742. RP BAKER, DN (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 9 TC 159 Z9 162 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 531 EP 541 DI 10.1109/36.225519 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100001 ER PT J AU COOK, WR CUMMINGS, AC CUMMINGS, JR GARRARD, TL KECMAN, B MEWALDT, RA SELESNICK, RS STONE, EC VONROSENVINGE, TT AF COOK, WR CUMMINGS, AC CUMMINGS, JR GARRARD, TL KECMAN, B MEWALDT, RA SELESNICK, RS STONE, EC VONROSENVINGE, TT TI MAST - A MASS-SPECTROMETER TELESCOPE FOR STUDIES OF THE ISOTOPIC COMPOSITION OF SOLAR, ANOMALOUS, AND GALACTIC COSMIC-RAY NUCLEI SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ENERGETIC PARTICLE; ABUNDANCES; COMPONENT; OXYGEN AB The Mass Spectrometer Telescope (MAST) on SAMPEX is designed to provide high resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z = 2 to 28) over the energy range from approximately 10 to several hundred MeV/nuc. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium. C1 NASA,GODDARD SPACE FLIGHT CTR,LOW ENERGY COSMIC RAY GRP,GREENBELT,MD 20771. CALTECH,SPACE RADIAT LAB,PASADENA,CA 91125. RP COOK, WR (reprint author), CALTECH,DOWNS LAB 22047,PASADENA,CA 91125, USA. NR 25 TC 50 Z9 50 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 557 EP 564 DI 10.1109/36.225522 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100004 ER PT J AU COOK, WR CUMMINGS, AC CUMMINGS, JR GARRARD, TL KECMAN, B MEWALDT, RA SELESNICK, RS STONE, EC BAKER, DN VONROSENVINGE, TT BLAKE, JB CALLIS, LB AF COOK, WR CUMMINGS, AC CUMMINGS, JR GARRARD, TL KECMAN, B MEWALDT, RA SELESNICK, RS STONE, EC BAKER, DN VONROSENVINGE, TT BLAKE, JB CALLIS, LB TI PET - A PROTON ELECTRON TELESCOPE FOR STUDIES OF MAGNETOSPHERIC, SOLAR, AND GALACTIC PARTICLES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ENERGETIC PARTICLE; MIDDLE ATMOSPHERE AB The Proton/Electron Telescope (PET) on SAMPEX is designed to provide measurements of energetic electrons and light nuclei from solar, galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from approximately 1 to approximately 30 MeV and H and He nuclei from approximately 20 to approximately 300 MeV/nuc, with isotope resolution of H and He extending from approximately 20 to approximately 80 MeV/nuc. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z > 2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP COOK, WR (reprint author), CALTECH,PASADENA,CA 91125, USA. NR 22 TC 81 Z9 83 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 565 EP 571 DI 10.1109/36.225523 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100005 ER PT J AU SALU, Y TILTON, J AF SALU, Y TILTON, J TI CLASSIFICATION OF MULTISPECTRAL IMAGE DATA BY THE BINARY DIAMOND NEURAL-NETWORK AND BY NONPARAMETRIC, PIXEL-BY-PIXEL METHODS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID LANDSAT AB The classification of multispectral image data obtained from satellites has become an important tool for generating ground cover maps. This study deals with the application of nonparametric pixel-by-pixel classification methods in the classification of pixels, based on their multispectral data. A new neural network, the Binary Diamond, is introduced, and its performance is compared with a nearest neighbor algorithm and a back-propagation network. The Binary Diamond is a multilayer, feed-forward neural network, which learns from examples in unsupervised, ''one-shot'' mode. It recruits its neurons according to the actual training set, as it learns. The comparisons of the algorithms were done by using a realistic data base, consisting of approximately 90 000 Landsat 4 Thematic Mapper pixels. The Binary Diamond and the nearest neighbor performances were close, with some advantages to the Binary Diamond. The performance of the back-propagation network lagged behind. An efficient nearest neighbor algorithm, the binned nearest neighbor, is described. Ways for improving the performances, such as merging categories, and analyzing nonboundary pixels, are addressed and evaluated. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,GREENBELT,MD 20771. HOWARD UNIV,CSTEA,WASHINGTON,DC 20059. RP SALU, Y (reprint author), HOWARD UNIV,DEPT PHYS,WASHINGTON,DC 20059, USA. NR 26 TC 21 Z9 23 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 606 EP 617 DI 10.1109/36.225528 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100010 ER PT J AU WONG, YF POSNER, EC AF WONG, YF POSNER, EC TI A NEW CLUSTERING-ALGORITHM APPLICABLE TO MULTISPECTRAL AND POLARIMETRIC SAR IMAGES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID CLASSIFICATION; CALIBRATION AB We describe an application of a scale-space clustering algorithm to the classification of a multispectral and polarimetric SAR image of an agricultural site. After the initial polarimetric and radiometric calibration and noise cancellation, we extracted a 12-dimensional feature vector for each pixel from the scattering matrix. The clustering algorithm was able to partition a set of unlabeled feature vectors from 13 selected sites, each site corresponding to a distinct crop, into 13 clusters without any supervision. The cluster parameters were then used to classify the whole image. The classification map is much less noisy and more accurate than those obtained by hierarchical rules. Starting with every point as a cluster, the algorithm works by melting the system to produce a tree of clusters in the scale space. It can cluster data in any multidimensional space and is insensitive to variability in cluster densities, sizes and ellipsoidal shapes. This algorithm, more powerful than existing ones, may be useful for remote sensing for land use. C1 CALTECH,DEPT ELECT ENGN,PASADENA,CA 91125. JET PROP LAB,PASADENA,CA 91109. RP WONG, YF (reprint author), LAWRENCE LIVERMORE NATL LAB,INST SCI COMP RES,LIVERMORE,CA 94551, USA. NR 26 TC 40 Z9 43 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 634 EP 644 DI 10.1109/36.225530 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100012 ER PT J AU HALPERN, D AF HALPERN, D TI VALIDATION OF SPECIAL SENSOR MICROWAVE IMAGER MONTHLY-MEAN WIND-SPEED FROM JULY 1987 TO DECEMBER 1989 SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID OCEAN; PACIFIC; SSM/I; SEA AB Since July 1987 the Remote Sensing Systems, Santa Rosa, California, routinely computes from first principles the wind speed from Special Sensor Microwave Imager (SSM/I) measurements of the intensity of microwave radiation emitted at the ocean surface. The accuracy of monthly-mean SSM/I wind speeds is determined by comparisons with moored-buoy wind measurements, which were recorded by four different institutions at 44 sites in the Atlantic and Pacific Oceans during July 1987 to December 1989. All results for 1988 were virtually identical with 1989. The range of monthly mean moored-buoy wind speeds was 2-10 ms-1. During 1987, the equatorial matchups were not equivalent with 1988 and 1989, and the cause remains unknown. The root-mean-square (rms) difference of 697 monthly-mean matchups of the composite 1988 and 1989 data set was 1.2 ms-1. The rms differences were smaller in the equatorial zone and higher in middle latitudes, in accord with the monthly standard deviation. At middle latitudes the time series of rms differences displayed an annual cycle. In the equatorial zone the agreement between SSM/I and in situ data was better in regions with a lesser amount of clouds, and vice versa. For SSM/I monthly standard deviations of 1-2, 2-3, and 3-4 ms-1, the average absolute values of the monthly-mean difference between SSM/I and moored-buoy wind speeds were 0.6, 0.9, and 1.4 ms-1, respectively. C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. RP HALPERN, D (reprint author), JET PROP LAB,DIV EARTH SCI & SPACE,PASADENA,CA 91109, USA. NR 29 TC 15 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1993 VL 31 IS 3 BP 692 EP 699 DI 10.1109/36.225535 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA LQ901 UT WOS:A1993LQ90100017 ER PT J AU KRAFT, LA KANKAM, MD AF KRAFT, LA KANKAM, MD TI MODELING A SINGLE-PHASE, VOLTAGE-CONTROLLED RECTIFIER USING LAPLACE TRANSFORMS SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article DE HARMONIC POWER FLOW; LAPLACE TRANSFORMS; RECTIFIER; MODELING; SPACECRAFT; VOLTAGE CONTROLLED; SINGLE PHASE ID HARMONIC POWER FLOW AB The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficients of the differential equations which model the line current to the rectifier directly. C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP KRAFT, LA (reprint author), VALPARAISO UNIV, VALPARAISO, IN 46383 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD MAY PY 1993 VL 8 IS 2 BP 388 EP 394 DI 10.1109/59.260848 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA LH396 UT WOS:A1993LH39600002 ER PT J AU VELUSAMY, K GARG, VK AF VELUSAMY, K GARG, VK TI LEADING-EDGE EFFECT DURING TRANSIENT BUOYANCY INDUCED FLOW ADJACENT TO A VERTICAL CYLINDER SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID PLATE AB The rate of propagation of the leading edge effect (LEE) during transient natural convection adjacent to a vertical solid cylinder is estimated from five different criteria. The cylinder has an appreciable thermal capacity and is subjected to a sudden heat generation. Numerical results are presented for a wide range of cylinder radii and heat flux values for two fluids, air and water. It is found that unlike the case of a flat plate, there is no unique criterion which would always estimate the fastest rate of propagation of LEE in water. However in air, the criterion due to Brown and Riley (J. Fluid Mech. 59, 225-237 (1973)) always predicts the fastest rate of propagation. Also, the effect of cylinder radius on the rate at which the LEE propagates through different fluids is different. For identical conditions, the LEE propagates faster in air than in water, as expected. Present results obtained by dropping the curvature terms in the governing equations match very well with previous analytical results for a flat plate. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP VELUSAMY, K (reprint author), INDIRA GANDHI CTR ATOM RES,THERMAL HYDRAUL SECT,KALPAKKAM 603102,INDIA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD MAY PY 1993 VL 36 IS 7 BP 1853 EP 1858 DI 10.1016/S0017-9310(05)80172-3 PG 6 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA LA335 UT WOS:A1993LA33500016 ER PT J AU CONROY, BL HOPPE, DJ IMBRIALE, WA AF CONROY, BL HOPPE, DJ IMBRIALE, WA TI BROAD-BAND VENETIAN BLIND POLARIZER WITH DUAL VANES SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article AB During development of a Venetian Blind polarizer, high reflections and substantial pattern deformation were noted. Analysis showed that when the polarizer was illuminated slightly off axis, a degenerate mode was excited This mode is resonant at the design center frequency, and was the cause of the problems. A design developed using dual vanes has been shown to be free of the problem. It also has greater bandwidth. RP CONROY, BL (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD MAY PY 1993 VL 14 IS 5 BP 987 EP 996 DI 10.1007/BF02084574 PG 10 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA LC915 UT WOS:A1993LC91500007 ER PT J AU WU, TK AF WU, TK TI QUASI-OPTICAL GRIDS WITH THIN RECTANGULAR PATCH APERTURE ELEMENTS SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article ID FREQUENCY SELECTIVE SURFACES; SCATTERING; APPROXIMATION; STRIP AB Theoretical analysis is presented for an efficient and accurate performance evaluation of quasi-optical grids comprised of thin rectangular patch/aperture elements with/without a dielectric substrate/superstrate. The convergence rate of this efficient technique is improved by an order of magnitude with the approximate edge conditions incorporated in the basis functions of the integral equation solution. Also presented are the interesting applications of this efficient analytical technique to the design and performance evaluation of the coupling grids and beam splitters in the optical systems as well as thermal protection sunshields used in the communication systems of satellites and spacecrafts. RP WU, TK (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD MAY PY 1993 VL 14 IS 5 BP 1017 EP 1033 DI 10.1007/BF02084577 PG 17 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA LC915 UT WOS:A1993LC91500010 ER PT J AU GHAFFARI, F LUCKRING, JM THOMAS, JL BATES, BL BIEDRON, RT AF GHAFFARI, F LUCKRING, JM THOMAS, JL BATES, BL BIEDRON, RT TI MULTIBLOCK NAVIER-STOKES SOLUTIONS ABOUT THE F/A-18 WING-LEX-FUSELAGE CONFIGURATION SO JOURNAL OF AIRCRAFT LA English DT Article AB Three-dimensional thin-layer Navier-Stokes computations are presented for the F/A-18 configuration. The modeled configuration includes an accurate surface representation of the fuselage, leading-edge extension (LEX), and wing, both with and without leading-edge flap deflection. A multiblock structured grid strategy is employed to decompose the computational flowfield domain around the subject configuration. Steady-state solutions are obtained from an algorithm that solves the compressible Navier-Stokes equations with an upwind-biased, nux-difference splitting approach. The results presented are based on a fully turbulent flow assumption, simulating the high Reynolds number flow conditions that correspond to a recent F/A-18 flight experiment. Good agreements between the computations and the flight test results are obtained for both surface flow patterns as well as surface pressure distributions. Furthermore, a correlation between the computed LEX vortex-core and the flight test results, observed by way of smoke visualization, is also presented. RP GHAFFARI, F (reprint author), NASA,LANGLEY RES CTR,DIV APPL AERODYNAM,HAMPTON,VA 23665, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1993 VL 30 IS 3 BP 293 EP 303 DI 10.2514/3.46333 PG 11 WC Engineering, Aerospace SC Engineering GA LF304 UT WOS:A1993LF30400003 ER PT J AU DARDEN, CM AF DARDEN, CM TI LIMITATIONS OF LINEAR-THEORY FOR SONIC-BOOM CALCULATIONS SO JOURNAL OF AIRCRAFT LA English DT Article AB Current sonic boom minimization theories have been reviewed to emphasize the capabilities and flexibilities of the methods. Preliminary comparisons of sonic booms predicted for two Mach 3 concepts illustrate the benefits of shaping. Finally, for very simple bodies of revolution, sonic boom predictions were made using two method-a modified linear theory method and a nonlinear method-for both far-field N-waves and midfield signature shapes. Preliminary analysis on these simple bodies verified that current modified linear theory prediction methods become inadequate for predicting midfield signatures for Mach numbers above three. The importance of impulse in sonic boom response and the importance of three-dimensional effects which could not be simulated with the bodies of revolution will determine the validity of current modified linear theory methods in predicting midfield signatures at lower Mach numbers. RP DARDEN, CM (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1993 VL 30 IS 3 BP 309 EP 314 DI 10.2514/3.46335 PG 6 WC Engineering, Aerospace SC Engineering GA LF304 UT WOS:A1993LF30400005 ER PT J AU CHADERJIAN, NM AF CHADERJIAN, NM TI COMPARISON OF 2 NAVIER-STOKES CODES FOR SIMULATING HIGH-INCIDENCE VORTICAL FLOW SO JOURNAL OF AIRCRAFT LA English DT Article AB Computations from two Navier-Stokes codes, NSS and F3D, are presented for a tangent-ogive cylinder body at high angle of attack. Features of this steady flow include a pair of primary vortices on the leeward side of the body, as well as secondary vortices. The topological and physical plausibility of this vortical structure is discussed. The accuracy of these codes are assessed by comparison of the numerical solutions with experimental data. The effects of turbulence model, numerical dissipation, and grid refinement are presented. The overall efficiency of these codes are also assessed by examining their convergence rates, computational time per time step, and maximum allowable time step for time-accurate computations. Overall, the numerical results from both codes compared equally well with experimental data, however, the NSS code was found to be significantly more efficient than the F3D code. RP CHADERJIAN, NM (reprint author), NASA,AMES RES CTR,APPL COMPUTAT FLUIDS BRANCH,MOFFETT FIELD,CA 94035, USA. NR 0 TC 3 Z9 3 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1993 VL 30 IS 3 BP 357 EP 364 DI 10.2514/3.46342 PG 8 WC Engineering, Aerospace SC Engineering GA LF304 UT WOS:A1993LF30400012 ER PT J AU BESS, TD SMITH, GL AF BESS, TD SMITH, GL TI EARTH RADIATION BUDGET - RESULTS OF OUTGOING LONGWAVE RADIATION FROM NIMBUS-7, NOAA-9, AND ERBS SATELLITES SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB Eighteen months of wide field-of-view (WFOV) outgoing longwave radiation (OLR) measurements from the Earth Radiation Budget Experiment (ERBF) NOAA-9 and NOAA-10 spacecraft have been deconvolved to produce resolution-enhanced flux maps at the top of the atmosphere. NOAA-9 had a 0230 LST equator-crossing time, and NOAA-10 a 0730 LST equator-crossing time. Intercomparison of these results with ERBE scanner and numerical filtered WFOV results is made. Results have also been compared with corresponding months of deconvolved results from the Nimbus-7 spacecraft (1200 LST equator crossing). Comparisons have been made of zonal profile plots of OLR for the different sensors and of contour maps of differences in OLR between sensors. In general Nimbus-7 OLR results show reasonable agreement with NOAA-9 and NOAA-10 over most regions of the globe. The largest differences occur over the extratropics, noticeably over land and especially over deserts. This study suggests that long-term monitoring of OLR with WFOV sensors is feasible for globally averaged trends to an accuracy of less than 1 W m-2, for the global absolute mean to within 3 W m-2, and for regional monthly means to within 8 W m-2 for most of the globe. Global averages for numerical filtered and deconvolved NOAA-9 WFOV results are consistently higher than Nimbus-7 deconvolved results because NOAA-9 results over land and deserts are higher. However, the ERBE NOAA-9 scanner gives smaller values of OLR over most regions of the globe than either the NOAA-9 WFOV numerical filtered or WFOV deconvolved results. RP BESS, TD (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23681, USA. NR 17 TC 5 Z9 6 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 1993 VL 32 IS 5 BP 813 EP 824 DI 10.1175/1520-0450(1993)032<0813:ERBROO>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LB224 UT WOS:A1993LB22400001 ER PT J AU BRUTSAERT, W HSU, AY SCHMUGGE, TJ AF BRUTSAERT, W HSU, AY SCHMUGGE, TJ TI PARAMETERIZATION OF SURFACE HEAT FLUXES ABOVE FOREST WITH SATELLITE THERMAL SENSING AND BOUNDARY-LAYER SOUNDINGS SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TEMPERATURE MEASUREMENTS; HAPEX-MOBILHY; LAND-SURFACES; EVAPORATION; PROFILES; CHANNELS AB Satellite-derived surface temperature measurements can be used in conjunction with temperature and wind soundings in the boundary layer to determine the surface sensible heat flux from forests at the regional scale. The underlying formulation is derived on the basis of similarity principles applied to the unstable turbulent boundary layer in which the scalar roughness for sensible heat is determined by calibration. This is illustrated herein with data acquired during the HAPEX-MOBILHY (Hydrologic Atmospheric Pilot Experiment-Modelisation du Bilan Hydrique), which was conducted in the spring and summer of 1986 over a 100-km X 100-km square in southwestern France. The northwest, third of the area is covered by the Landes forest. The surface temperatures for a 25-km x 25-km area in this forested region were determined from the NOAA-9 Advanced Very High Resolution Radiometer (AVHRR) channels 4 and 5. Atmospheric corrections were applied with LOWTRAN-7 and measured atmospheric profiles, as well as with split-window techniques. The atmospheric profiles were obtained by interpolation of data from radiosondes launched from a clearing in the forest. The calculated fluxes were compared with those measured above the forest at the Institute of Hydrology (Wallingford, England) tower, some 4.5 km from the radiosonde launch site. The comparisons were favorable for 6 clear days but not for a day with partial cloud cover. The sensitivity of the results shows that the accuracy of the surface temperature measurements should be better than 0.5 K. The effect of the spatial scale of the surface temperature measurement on the scalar roughness is also considered. C1 NASA,GODDARD SPACE FLIGHT CTR,GSFC,HYDROL SCI BRANCH,GREENBELT,MD 20771. USDA ARS,BELTSVILLE AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705. RP BRUTSAERT, W (reprint author), CORNELL UNIV,SCH CIVIL & ENVIRONM ENGN,HOLLISTER HALL,ITHACA,NY 14853, USA. NR 23 TC 51 Z9 51 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 1993 VL 32 IS 5 BP 909 EP 917 DI 10.1175/1520-0450(1993)032<0909:POSHFA>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LB224 UT WOS:A1993LB22400009 ER PT J AU REID, MB AF REID, MB TI REDUCTION OF PLASMA ELECTRON-DENSITY IN A GAS IONIZED BY AN ELECTRON-BEAM - USE OF A GASEOUS DIELECTRIC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PERFLUOROCARBON COMPOUNDS; ATTACHMENT; LASER AB Propagation of an electron beam through a gas creates a secondary electron/ion plasma which can have subsequent deleterious effects on the propagation of the beam. In the case of pulsed electron beams with short micropulse durations, these effects can be greatly reduced through the use of a small doping fraction of an electron attachment gas. We present a model which allows the calculation of the reduction in unbound plasma electron density attainable with a gaseous dielectric dopant. Potential problems with a dopant, including increased ionization, increased scattering, altered refractive index, and dopant saturation and fragmentation, are discussed. RP REID, MB (reprint author), NASA,AMES RES CTR,MAIL STOP 269-3,MOFFETT FIELD,CA 94035, USA. NR 13 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1993 VL 73 IS 9 BP 4212 EP 4217 DI 10.1063/1.352826 PG 6 WC Physics, Applied SC Physics GA LA320 UT WOS:A1993LA32000012 ER PT J AU SINGH, J VELLAIKAL, M NARAYAN, J AF SINGH, J VELLAIKAL, M NARAYAN, J TI LASER-ENHANCED SYNTHESIS AND PROCESSING OF DIAMOND FILMS FROM LIQUID HYDROCARBONS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAS-PHASE; PLASMA AB We report synthesis of diamond films by pulsed laser irradiation on copper substrate immersed into liquid benzene. It is envisaged that carbon released from benzene at the liquid-solid interface is converted into diamond as a result of rapid quenching from a high temperature. The diamond crystallites were characterized using high resolution transmission electron microscopy imaging and electron diffraction techniques. Growth of thicker diamond films by subsequent chemical vapor deposition has been investigated by transmission and scanning electron microscopy techniques. Thin diamond film deposited during liquid phase provided seed for diamond growth during subsequent chemical vapor deposition. C1 N CAROLINA STATE UNIV,DEPT MAT SCI & ENGN,RALEIGH,NC 27695. RP SINGH, J (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAIL STOP EH23,HUNTSVILLE,AL 35812, USA. RI Narayan, Jagdish/D-1874-2009 NR 19 TC 30 Z9 30 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1993 VL 73 IS 9 BP 4351 EP 4356 DI 10.1063/1.352819 PG 6 WC Physics, Applied SC Physics GA LA320 UT WOS:A1993LA32000033 ER PT J AU SIEG, RM ALTEROVITZ, SA WARNER, JD AF SIEG, RM ALTEROVITZ, SA WARNER, JD TI ELLIPSOMETRIC STUDY OF AMBIENT-PRODUCED OVERLAYER GROWTH-RATE ON YBA2CU3O7-X FILMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TEMPERATURE; ANISOTROPY; GAAS; SI AB An ellipsometric study of ambient-reaction-produced BaCO3 overlayer growth on laser-ablated YBa2Cu3O7-x is presented as a function of time. The effects of the anisotropy of YBa2Cu3O7-x on the ellipsometric data inversion process are discussed, and it is concluded that with certain restrictions on the data acquisition method, the anisotropic substrate can be adequately modeled by its isotropic pseudodielectric function for the purpose of overlayer thickness estimation. It is found that after an initial period of rapid growth attributed to the chemical reaction of the exposed surface bonds, the BaCO3 overlayer growth is linear at 1-2 angstrom per day. This slow growth rate is attributed to the complexity of the BaCO3 forming reaction, together with the need for ambient reactants to diffuse through the overlayer. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SIEG, RM (reprint author), CLEVELAND STATE UNIV,CLEVELAND,OH 44115, USA. NR 15 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1993 VL 73 IS 9 BP 4357 EP 4361 DI 10.1063/1.352820 PG 5 WC Physics, Applied SC Physics GA LA320 UT WOS:A1993LA32000034 ER PT J AU HERZ, RK BADLANI, A SCHRYER, DR UPCHURCH, BT AF HERZ, RK BADLANI, A SCHRYER, DR UPCHURCH, BT TI 2-COMPONENT CATALYSTS FOR LOW-TEMPERATURE CO OXIDATION - A MONTE-CARLO STUDY SO JOURNAL OF CATALYSIS LA English DT Article ID SURFACE-REACTION MODEL; LATTICE GAS APPROACH; PHASE-TRANSITIONS; REACTION-KINETICS; HETEROGENEOUS CATALYSIS; CARBON-MONOXIDE; OSCILLATIONS; DIFFUSION; FLUCTUATIONS; SIMULATION C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP HERZ, RK (reprint author), UNIV CALIF SAN DIEGO,DEPT APPL MECH & ENGN SCI,CHEM ENGN GRP,LA JOLLA,CA 92093, USA. NR 49 TC 30 Z9 30 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY PY 1993 VL 141 IS 1 BP 219 EP 238 DI 10.1006/jcat.1993.1131 PG 20 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA KZ472 UT WOS:A1993KZ47200019 ER PT J AU CASPER, J ATKINS, HL AF CASPER, J ATKINS, HL TI A FINITE-VOLUME HIGH-ORDER ENO SCHEME FOR 2-DIMENSIONAL HYPERBOLIC SYSTEMS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID SHOCK-CAPTURING SCHEMES; EFFICIENT IMPLEMENTATION; DIFFERENCE-SCHEMES C1 NASA, LANGLEY RES CTR, THEORET FLOW PHYS BRANCH, HAMPTON, VA 23665 USA. RP VIGYAN INC, 30 RES DR, HAMPTON, VA 23666 USA. NR 18 TC 61 Z9 69 U1 0 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1993 VL 106 IS 1 BP 62 EP 76 DI 10.1006/jcph.1993.1091 PG 15 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA KY460 UT WOS:A1993KY46000006 ER PT J AU OLLA, BL DAVIS, MW AF OLLA, BL DAVIS, MW TI THE INFLUENCE OF LIGHT ON EGG BUOYANCY AND HATCHING RATE OF THE WALLEYE POLLOCK, THERAGRA-CHALCOGRAMMA SO JOURNAL OF FISH BIOLOGY LA English DT Article DE BEHAVIOR; BUOYANCY; DENSITY; EGGS; HATCHING; LIGHT ID VERTICAL-DISTRIBUTION; FISH EGGS; DENSITY RP OLLA, BL (reprint author), NATL MARINE FISHERIES SERV,HATFIELD MARINE SCI CTR,ALASKA FISHERIES SCI CTR,NEWPORT,OR 97365, USA. NR 15 TC 23 Z9 24 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD MAY PY 1993 VL 42 IS 5 BP 693 EP 698 PG 6 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA LD256 UT WOS:A1993LD25600006 ER PT J AU RODI, W MANSOUR, NN AF RODI, W MANSOUR, NN TI LOW-REYNOLDS-NUMBER KAPPA-EPSILON MODELING WITH THE AID OF DIRECT SIMULATION DATA SO JOURNAL OF FLUID MECHANICS LA English DT Article ID BOUNDARY-LAYER FLOWS; CHANNEL FLOW; TURBULENCE; STRESS; CLOSURE; WALL AB The constant C(mu) and the near-wall damping function f(mu) in the eddy-viscosity relation of the k-epsilon model are evaluated from direct numerical simulation (DNS) data for developed channel and boundary-layer flow, each at two Reynolds numbers. Various existing f(mu) model functions are compared with the DNS data, and a new function is fitted to the high-Reynolds-number channel flow data. The epsilon-budget is computed for the fully developed channel flow. The relative magnitude of the terms in the epsilon-equation is analysed with the aid of scaling arguments, and the parameter governing this magnitude is established. Models for the sum of all source and sink terms in the epsilon-equation are tested against the DNS data, and an improved model is proposed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP RODI, W (reprint author), UNIV KARLSRUHE,INST HYDROMECH,KAISERSTR 12,W-7500 KARLSRUHE,GERMANY. NR 22 TC 111 Z9 114 U1 0 U2 12 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAY PY 1993 VL 250 BP 509 EP 529 DI 10.1017/S0022112093001545 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA LF073 UT WOS:A1993LF07300019 ER PT J AU FARRUGIA, CJ BURLAGA, LF OSHEROVICH, VA RICHARDSON, IG FREEMAN, MP LEPPING, RP LAZARUS, AJ AF FARRUGIA, CJ BURLAGA, LF OSHEROVICH, VA RICHARDSON, IG FREEMAN, MP LEPPING, RP LAZARUS, AJ TI A STUDY OF AN EXPANDING INTERPLANETARY MAGNETIC CLOUD AND ITS INTERACTION WITH THE EARTHS MAGNETOSPHERE - THE INTERPLANETARY ASPECT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR ENERGETIC PARTICLES; GEOMAGNETIC STORMS; CORONAL TRANSIENT; FIELDS; EVENTS; SHOCKS AB In a series of three interlinked papers we present a study of an interplanetary magnetic cloud and its interaction with the Earth's magnetosphere on January 14/15, 1988. This first paper is divided into three parts describing the principal results concerning the magnetic cloud. First, by applying the cylindrically symmetric, magnetic flux rope model to the high time resolution magnetic field and plasma data obtained by the IMP-8 spacecraft, we show that the axis of the magnetic cloud in question is approximately in the ecliptic and orthogonal to the Earth-Sun line. We note the presence of pulsations of approximately 5-hour period in the bulk flow speed which are superimposed on an otherwise monotonically falling bulk speed profile. Second, we apply ideal MHD to model the self-similar, radial expansion of a magnetic cloud of cylindrical geometry. As initial condition for the magnetic field we choose a constant-alpha, force-free magnetic configuration. We demonstrate that the theoretical velocity profile for the free expansion of a magnetic cloud is consistent with observations made during the January 14/15, 1988, magnetic cloud encounter. Comparing model with data, we infer that prior to the start of observations at 1 AU the magnetic cloud had been expanding for 65.4 hours; the radius of the magnetic cloud at the time it arrived at Earth was 0.18 AU; and its expansion speed at 1 AU was approximately 114 km/s. Third, we discuss energetic (approximately 1 MeV) ion data, also from instrumentation on IMP-8. We highlight the appearance of a sharp enhancement in the intensity of approximately 0.5-MeV ions while IMP-8 was inside the cloud. These ions travel as a collimated, field-aligned beam from the west of the Sun. This is an ''impulsive'' solar event in which particles accelerated at a magnetically well-connected solar flare arrive promptly at the spacecraft. The observation of solar flare particles inside the cloud suggests that field lines within the magnetic cloud remained connected to the Sun. The observation is, however, inconsistent with the supposition that the cloud is formed of closed magnetic field loops disconnected from the Sun. C1 NASA GODDARD SPACE FLIGHT CTR,LANHAM,MD 20706. MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS,GREENBELT,MD 20771. UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. RP FARRUGIA, CJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. OI Richardson, Ian/0000-0002-3855-3634 NR 46 TC 138 Z9 141 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1993 VL 98 IS A5 BP 7621 EP 7632 DI 10.1029/92JA02349 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB643 UT WOS:A1993LB64300011 ER PT J AU FREEMAN, MP FARRUGIA, CJ BURLAGA, LF HAIRSTON, MR GREENSPAN, ME RUOHONIEMI, JM LEPPING, RP AF FREEMAN, MP FARRUGIA, CJ BURLAGA, LF HAIRSTON, MR GREENSPAN, ME RUOHONIEMI, JM LEPPING, RP TI THE INTERACTION OF A MAGNETIC CLOUD WITH THE EARTH - IONOSPHERIC CONVECTION IN THE NORTHERN AND SOUTHERN HEMISPHERES FOR A WIDE-RANGE OF QUASI-STEADY INTERPLANETARY MAGNETIC-FIELD CONDITIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-LATITUDE IONOSPHERE; POLAR-CAP CONVECTION; BIRKELAND CURRENTS; Y-COMPONENT; AMPTE-UKS; IMF-BY; MAGNETOPAUSE; PLASMA; RECONNECTION; CUSP AB We study the ionospheric convection that prevails during the passage of a magnetic cloud past the Earth. For the cloud studied here, January 13-15, 1988, the ionospheric convection was measured almost continually in cross sections of the polar cap and auroral zone by the Defense Meteorological Satellite Program (DMSP) polar-orbiting satellite. In turn, the conditions in the magnetic cloud are like those of a controlled laboratory experiment: First, the magnetic field changes smoothly and slowly on time scales much longer than the expected ionospheric response time, ensuring that the external interplanetary conditions giving rise to any ionospheric flow pattern are known to unprecedented accuracy. Second, over the longer time scale of the magnetic cloud passage, the magnetic field vector rotates by over 180-degrees such that the magnetic cloud divides into two intervals of northward (B(z) > 0) and southward (B(z) < 0) pointing interplanetary magnetic field (IMF) of 11 and 18 hours duration, respectively. During the former interval our observations show that (1) for strongly northward IMF (B(z) > 18 nT) the convection in one (the southern) hemisphere is characterized by a two-cell convection pattern confined to high latitudes (greater-than-or-equal-to 75-degrees) with sunward flow over the pole (''reverse'' two-cell convection). (2) The strength of the flows (approximately 1 km/s) is comparable to that seen under southward IMF later. (3) Superimposed on this convection pattern there are clear dawn-dusk asymmetries associated with a one-cell convection component whose sense depends on the polarity of the magnetic cloud's large east-west magnetic field component. (4) Whilst the flows in the southern hemisphere are ordered into a well-defined convection pattern, the flows in the northern hemisphere are very irregular, varying on short spatial scales. When the cloud's magnetic field turns southward the following observations were made: (1) The convection is characterized by a two-cell pattern extending to lower latitudes (approximately 50-degrees) with antisunward flow over the pole (''standard'' two-cell convection). (2) There is no evident interhemisphere difference in the structure and strength of the convection. (3) Superimposed dawn-dusk asymmetries in the flow pattern are observed which are only in part attributable to the east-west component of the magnetic field. (4) A dawn-dusk asymmetry in the latitude of the convection reversal boundary also exists, which is most pronounced in the northern hemisphere (up to 10-degrees difference). We study the transition from a reverse to standard two-cell convection pattern and find that because of the large B(z) component of the magnetic field inside the magnetic cloud, this transition actually takes place before the external field turns southward. It occurs when the magnetic shear angle between the subsolar magnetospheric field and the magnetic field of the magnetic cloud is approximately 70-degrees. We consider the effect of the B(z) component of the cloud magnetic field on the size of the open field line region or polar cap, inferred from the convection pattern. We argue that the long-term variation in the polar cap size is determined by the temporal gradient of the B(z) component. We investigate the strength of the ionospheric convection, parameterized by the maximum potential difference across the convection pattern, as a function of the B(z) component of the cloud magnetic field, extending the range of similar investigations. For strongly northward IMF a potential difference of 60-80 kV is observed across the reverse two-cell convection pattern. For southward IMF the potential difference across the standard two-cell convection pattern changes almost linearly with B(z), attaining its maximum value of approximately 180 kV at the extreme value of B(z) = -19 nT reached in this cloud. C1 UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. UNIV TEXAS,CTR SPACE SCI,PHYS PROGRAM,RICHARDSON,TX 75083. JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. BOSTON UNIV,CTR SPACE PHYS,BOSTON,MA 02215. NR 50 TC 81 Z9 81 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1993 VL 98 IS A5 BP 7633 EP 7655 DI 10.1029/92JA02350 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB643 UT WOS:A1993LB64300012 ER PT J AU FARRUGIA, CJ FREEMAN, MP BURLAGA, LF LEPPING, RP TAKAHASHI, K AF FARRUGIA, CJ FREEMAN, MP BURLAGA, LF LEPPING, RP TAKAHASHI, K TI THE EARTHS MAGNETOSPHERE UNDER CONTINUED FORCING - SUBSTORM ACTIVITY DURING THE PASSAGE OF AN INTERPLANETARY MAGNETIC CLOUD SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GEOMAGNETIC STORMS; CONVECTION; FIELD; MAGNETOPAUSE AB In this third paper on magnetic clouds and their interaction with the terrestrial magnetosphere we focus on substorm activity attending the 30-hour-long passage of the magnetic cloud seen at 1 AU on January 14/15, 1988. Our main aim is to describe high resolution field and plasma data from six spacecraft at geostationary orbit and beyond (up to 9 R(E)), supplemented by ground magnetograms, in order to estimate the number of substorm onsets that occurred during this passage. This analysis, attempted here for the first time over such an extended data interval, enables us to obtain a comprehensive view of the magnetospheric behavior. We then relate the interplanetary field and plasma input to the magnetospheric and ionospheric output. The paper is a case study of the response of the nightside magnetosphere to particularly well-behaved interplanetary conditions: the variations with time of the field and plasma parameters in the magnetic cloud are simple; and the north-south (B(z)) and east-west (B(y)) components of the magnetic field range slowly over approximately 20 nT on both sides of zero. From a synopsis of the substorm observations we find that during die earlier 11-h interval when B(z) was continuously positive, the magnetosphere was quiescent, whereas in the later 18-h interval, when B(z) was uninterruptedly negative, a large magnetic storm was set off. In this latter interval the substorm onsets recur on average every 50 min. Their average recurrence frequency remains relatively undiminished even when the magnetic cloud B(z) and other measures of the interplanetary energy input have decreased considerably. We find these results to concur with the current models of magnetospheric substorms based on deterministic nonlinear dynamics. Using ancillary information from HF radar observations of ionospheric convection, we investigate the magnetospheric conditions preceding the first substorm onset in the long substorm sequence. We find that it occurred when the cloud's magnetic field had a persistent northward component but was predominantly westward pointing. C1 JOHNS HOPKINS UNIV,APPL PHYS LAB,LAUREL,MD 20723. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. RP FARRUGIA, CJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 43 TC 95 Z9 95 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1993 VL 98 IS A5 BP 7657 EP 7671 DI 10.1029/92JA02351 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB643 UT WOS:A1993LB64300013 ER PT J AU DENG, W KILLEEN, TL BURNS, AG ROBLE, RG SLAVIN, JA WHARTON, LE AF DENG, W KILLEEN, TL BURNS, AG ROBLE, RG SLAVIN, JA WHARTON, LE TI THE EFFECTS OF NEUTRAL INERTIA ON IONOSPHERIC CURRENTS IN THE HIGH-LATITUDE THERMOSPHERE FOLLOWING A GEOMAGNETIC STORM SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GENERAL-CIRCULATION MODEL; INTERPLANETARY MAGNETIC-FIELD; ATMOSPHERIC SOLAR TIDES; POLAR-CAP; F-REGION; PLASMA CONVECTION; CURRENT SYSTEM; NORTHWARD IMF; DYNAMICS; WINDS AB Results of an experimental and theoretical investigation into the effects of the time dependent neutral wind flywheel on high-latitude ionospheric electrodynamics are presented. The results extend our previous work (Deng et al., 19911 which used the National Center for Atmospheric Research Thermosphere/Ionosphere General Circulation Model (NCAR TIGCM) to theoretically simulate flywheel effects in the aftermath of a geomagnetic storm. The previous results indicated that the neutral circulation, set up by ion-neutral momentum coupling in the main phase of a geomagnetic storm, is maintained for several hours after the main phase has ended and may dominate height-integrated Hall currents and field-aligned currents for up to 4-5 hours. We extend the work of Deng et al. to include comparisons between the calculated time-dependent ionospheric Hall current system in the storm-time recovery period and that measured by instruments on board the Dynamics Explorer 2 (DE 2) satellite. Also, comparisons are made between calculated field-aligned currents and those derived from DE 2 magnetometer measurements. These calculations also allow us to calculate the power transfer rate (sometimes called the Poynting flux) between the magnetosphere and ionosphere. The following conclusions have been drawn: (1) Neutral winds can contribute significantly to the horizontal ionospheric current system in the period immediately following the main phase of a geomagnetic storm, especially over the magnetic polar cap and in regions of ion drift shear. (2) Neutral winds drive Hall currents that flow in the opposite direction to those driven by ion drifts. (3) The overall morphology of the calculated field-aligned current system agrees with previously published observations for the interplanetary magnetic field (IMF) B(Z) southward conditions, although the region I and region 2 currents are smeared by the TIGCM model grid resolution. (4) Neutral winds can make significant contributions to the field-aligned current system when B(Z) northward conditions prevail following the main phase of a storm, but can account for only a fraction of the observed currents. (5) DE 2 measurements provide a demonstration of ''local'' (satellite-altitude) flywheel effects. (6) On the assumption that the magnetosphere acts as an insulator, we calculate neutral-wind-induced polarization electric fields of approximately 20-30 kV in the period immediately following the geomagnetic storm. C1 NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80303. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP DENG, W (reprint author), UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES,ANN ARBOR,MI 48109, USA. RI Slavin, James/H-3170-2012; Killeen, Timothy/F-2215-2013; Burns, Alan/L-1547-2013 OI Slavin, James/0000-0002-9206-724X; NR 45 TC 33 Z9 33 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1993 VL 98 IS A5 BP 7775 EP 7790 DI 10.1029/92JA02268 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB643 UT WOS:A1993LB64300024 ER PT J AU RAO, MN GARRISON, DH BOGARD, DD REEDY, RC AF RAO, MN GARRISON, DH BOGARD, DD REEDY, RC TI SOLAR-FLARE-IMPLANTED HE-4 HE-3 AND SOLAR-PROTON-PRODUCED NE AND AR CONCENTRATION PROFILES PRESERVED IN LUNAR ROCK 61016 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID CROSS-SECTIONS; NOBLE-GASES; ISOTOPIC COMPOSITION; EXPOSURE AGES; METEORITES; PARTICLES; HELIUM; NUCLEI; ABUNDANCES; SOIL AB Documented near-surface samples from oriented lunar rock 61016 have yielded the first measurements of depth profiles for Ne-21, Ne-22, and Ar-38 isotopes produced in situ from nuclear interactions of energetic solar flare protons. Further, the cosmogenic Ne-21/Ne-22 ratios are distinct for different proton energy ranges and increase systematically with increasing shielding. This variation in cosmogenic Ne-21/Ne-22 represents a progression from a mixed component produced from solar flare protons (SCR) and galactic cosmic rays (GCR) to a pure GCR component. Using the 2 m.y. exposure age for 61016, the calculated production rates for SCR Ne-21 and Ar-38 from solar energetic protons in near-surface samples agree within 5% and 25%, respectively, with theoretical estimates. Calculated GCR production rates for Ne-21 and Ar-22 in the deepest (26 mm) samples agree within 25% and 10%, respectively, with theoretical estimates. Combined SCR and GCR concentration profiles for Ne-21/Ne-22, and Ar-38 match theoretical calculations based on an omnidirectional flux above 10 MeV of 100 protons cm-2 s-1 with an exponential rigidity between 70 and 85 MV and a surface erosion rate of 1 mm m.y.-1. Selectively etched, near-surface samples suggest a long-term average He-4/He-3 ratio of approximately 770 for implanted solar flare nuclei with E > approximately 4 MeV amu-1, and a He-4/He-3 ratio of approximately 3450 for solar flare nuclei with E > -1 McV amu-1. Averaged over long term, the solar flare He-4/He-3 ratio appears energy dependent. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77258. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP RAO, MN (reprint author), LUNAR & PLANETARY INST,3600 BAY AREA BLVD,HOUSTON,TX 77058, USA. NR 39 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1993 VL 98 IS A5 BP 7827 EP 7835 DI 10.1029/93JA00002 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LB643 UT WOS:A1993LB64300029 ER PT J AU LEMBECK, CA PRUSSING, JE AF LEMBECK, CA PRUSSING, JE TI OPTIMAL IMPULSIVE INTERCEPT WITH LOW-THRUST RENDEZVOUS RETURN SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID CIRCULAR ORBIT; MANEUVERS AB Primer vector theory is used to investigate a specific class of minimum-fuel spacecraft trajectory problems in which high- and low-thrust propulsion systems are utilized sequentially. The problem considered assumes a spacecraft initially on-station in an established orbit about the Earth. It is desired to intercept a predetermined position in space in a timely manner for collision avoidance or platform surveillance, using an optimal high-thrust program. The spacecraft then returns to the original orbit station using optimal low-thrust propulsion. Fixed-time minimum-fuel solutions are obtained using the Clohessy-Wiltshire linearized dynamic model. In the time-open case, the optimal final time is unbounded. For this case a composite performance index involving both fuel consumption and the final time is minimized to obtain optimal finite-time solutions. C1 UNIV ILLINOIS,URBANA,IL 61801. RP LEMBECK, CA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE SHUTTLE PROGRAM,HOUSTON,TX 77058, USA. NR 25 TC 32 Z9 34 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1993 VL 16 IS 3 BP 426 EP 433 DI 10.2514/3.21027 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA LC611 UT WOS:A1993LC61100002 ER PT J AU MOERDER, DD CALISE, AJ CLEMMONS, P AF MOERDER, DD CALISE, AJ CLEMMONS, P TI OPTIMAL OPEN MULTISTEP DISCRETIZATION FORMULAS FOR REAL-TIME SIMULATION SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB The performance of digital real-time simulations is considered. A figure of merit is derived that quantifies a simulation's fidelity in terms of the time-domain discrepancy between its output and that of the plant it simulates, assuming that the plant is linearizable and asymptotically stable. This performance index is then used in deriving an easily automated procedure for calculating optimal values for free parameters in plant discretizations based on a generalized form of open linear multistep integration formulas. The theory is demonstrated in simulating the rigid-body dynamics of a fully articulated helicopter rotor blade system. C1 GEORGIA INST TECHNOL,SCH AEROSP ENGN,ATLANTA,GA 30332. RP MOERDER, DD (reprint author), NASA,LANGLEY RES CTR,SPACECRAFT CONTROL BRANCH,HAMPTON,VA 23665, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1993 VL 16 IS 3 BP 557 EP 563 DI 10.2514/3.21045 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA LC611 UT WOS:A1993LC61100020 ER PT J AU TAKAHASHI, MD AF TAKAHASHI, MD TI SYNTHESIS AND EVALUATION OF AN H-2 CONTROL LAW FOR A HOVERING HELICOPTER SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB The design and simulator evaluation of a rate-command flight-control law for a UH-60 helicopter in near-hover flight conditions are described. The multivariable control law was synthesized using an H-2 method, which, through weighting functions, directly shapes the singular values of the sensitivity (I + GK)-1, complementary sensitivity GK(I + GK)-1, and control input K(I + GK)-1 transfer-function matrices. The design was implemented on the vertical motion simulator, and four low-speed hover tasks were used to evaluate the control system characteristics. The pilot comments indicated good decoupling and quick response characteristics, but also revealed a mild pilot-induced oscillation tendency in the roll axis. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 14 TC 11 Z9 12 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1993 VL 16 IS 3 BP 579 EP 584 DI 10.2514/3.21048 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA LC611 UT WOS:A1993LC61100023 ER PT J AU CAMCI, C KIM, K HIPPENSTEELE, SA POINSATTE, PE AF CAMCI, C KIM, K HIPPENSTEELE, SA POINSATTE, PE TI EVALUATION OF A HUE CAPTURING BASED TRANSIENT LIQUID-CRYSTAL METHOD FOR HIGH-RESOLUTION MAPPING OF CONVECTIVE HEAT-TRANSFER ON CURVED SURFACES SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article AB Accurate determination of convective heat transfer coefficients on complex curved surfaces is essential in the aerothermal design and analysis of propulsion system components. The heat transfer surfaces are geometrically very complex in most of the propulsion applications. This study focuses on the evaluation of a hue capturing technique for the heat transfer interpretation of liquid crystal images from a complex curved heat transfer surface. Impulsively starting heat transfer experiments in a square to rectangular transition duct are reported. The present technique is different from existing steady-state hue capturing studies. A real-time hue conversion process on a complex curved surface is adopted for a transient heat transfer technique with high spatial resolution. The study also focuses on the use of encapsulated liquid crystals with narrow color band in contrast to previous steady-state hue based techniques using wide band liquid crystals. Using a narrow band crystal improves the accuracy of the heat transfer technique. Estimated uncertainty for the heat transfer coefficient from the technique is about 5.9 percent. A complete heat transfer map of the bottom surface was possible using only seven liquid crystal image frames out of the 97 available frames during the transient experiment. Significant variations of heat transfer coefficients are quantitatively visualized on the curved surfaces of the transition duct. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP CAMCI, C (reprint author), PENN STATE UNIV,DEPT AEROSP ENGN,UNIV PK,PA 16802, USA. NR 31 TC 41 Z9 43 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD MAY PY 1993 VL 115 IS 2 BP 311 EP 318 DI 10.1115/1.2910681 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA LE445 UT WOS:A1993LE44500004 ER PT J AU YAO, XS FEINBERG, J LOGAN, R MALEKI, L AF YAO, XS FEINBERG, J LOGAN, R MALEKI, L TI LIMITATIONS ON PEAK PULSE POWER, PULSE-WIDTH, AND CODING MASK MISALIGNMENT IN A FIBEROPTIC CODE-DIVISION MULTIPLE-ACCESS SYSTEM SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article ID SELF-PHASE-MODULATION; SINGLE-MODE FIBERS; FEMTOSECOND PULSES; FREQUENCY SHIFT; DISPERSION; PROPAGATION; WAVELENGTH AB We analyze the effects of a fiber's dispersion and optical nonlinearity on a code-division multiple-access communications system. Such a system encodes each channel by scrambling the relative phases of each pulse's frequency spectrum. We assume that each transmitter has a unique phase-encoding mask to scramble the pulses, and that the intended receiver has the complementary phase-decoding mask to unscramble the pulses. We derive the necessary nonlinear pulse propagation equation using a new and systematic approach. We then determine the minimum allowable pulse width for the system, which is set by the fiber's group-velocity dispersion. We also determine the maximum pulse width, which is set by the spectral resolution of the coding apparatus, and which is a function of the code length and the laser beam's diameter. We next calculate the maximum optical power, which is limited by the fiber's self-phase modulation. This power is significantly larger than the minimum detectable optical power determined by the noise in the electrical receiver, so that in practice any distortion caused by the fiber's optical nonlinearity can be avoided. From our calculations we provide estimates for all important optical parameters. We also investigate the deleterious effect of a slight relative misalignment between the encoding and decoding masks. C1 UNIV SO CALIF,DEPT ELECT ENGN,LOS ANGELES,CA 90089. UNIV SO CALIF,DEPT PHYS,LOS ANGELES,CA 90089. JET PROP LAB,TIME & FREQUENCY SYST RES GRP,PASADENA,CA 91109. RP YAO, XS (reprint author), JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. NR 34 TC 5 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 SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD MAY-JUN PY 1993 VL 11 IS 5-6 BP 836 EP 846 DI 10.1109/50.233247 PG 11 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA LY248 UT WOS:A1993LY24800017 ER PT J AU BANSAL, NP AF BANSAL, NP TI COMPOSITION DEPENDENCE OF SUPERCONDUCTIVITY IN YBA2(CU3-XALX)OY SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID PEROVSKITE; SUBSTITUTION; YBA2CU3O7-X; OXYGEN AB Eleven different compositions in the system YBa2(Cu3-xAlx)Oy(x = 0-0.3) have been synthesized and characterized by electrical resistivity measurements, powder X-ray diffraction, and scanning electron microscopy. The superconducting transition temperature, T(c)(onset), was almost unaffected by the presence of alumina due to its limited solubility in YBa2Cu3O7-x. However, T(c)(R = 0) gradually decreased and the resistive tails became longer with increasing Al2O3 concentration. This was probably due to formation of BaAl2O4 and other impurity phases from chemical decomposition of the superconducting phase by reaction with Al2O3. RP BANSAL, NP (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAY 1 PY 1993 VL 28 IS 9 BP 2433 EP 2437 DI 10.1007/BF01151676 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA LB030 UT WOS:A1993LB03000025 ER PT J AU BIRK, M WINNEWISSER, M COHEN, EA AF BIRK, M WINNEWISSER, M COHEN, EA TI THE HIGH-RESOLUTION FOURIER-TRANSFORM FAR-INFRARED SPECTRUM OF CYANAMIDE, H2NCN SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ROTATION-INVERSION SPECTRUM; MILLIMETER WAVE REGION C1 JET PROP LAB,PASADENA,CA 91109. NR 10 TC 14 Z9 14 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 1993 VL 159 IS 1 BP 69 EP 78 DI 10.1006/jmsp.1993.1105 PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA KZ462 UT WOS:A1993KZ46200007 ER PT J AU RINSLAND, CP SMITH, MAH GOLDMAN, A DEVI, VM BENNER, DC AF RINSLAND, CP SMITH, MAH GOLDMAN, A DEVI, VM BENNER, DC TI THE FUNDAMENTAL BANDS OF (HCL)-CL-35 AND (HCL)-CL-37 - LINE POSITIONS FROM HIGH-RESOLUTION LABORATORY DATA SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Note ID HCL; COEFFICIENTS; CONSTANTS; SPECTRUM; HF C1 UNIV DENVER,DEPT PHYS,DENVER,CO 80208. COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187. RP RINSLAND, CP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401A,HAMPTON,VA 23665, USA. NR 19 TC 27 Z9 29 U1 2 U2 11 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 1993 VL 159 IS 1 BP 274 EP 278 DI 10.1006/jmsp.1993.1124 PG 5 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA KZ462 UT WOS:A1993KZ46200026 ER PT J AU FISHBEIN, E PATTERSON, RT AF FISHBEIN, E PATTERSON, RT TI ERROR-WEIGHTED MAXIMUM-LIKELIHOOD (EWML) - A NEW STATISTICALLY BASED METHOD TO CLUSTER QUANTITATIVE MICROPALEONTOLOGICAL DATA SO JOURNAL OF PALEONTOLOGY LA English DT Article AB The advent of readily available computer-based clustering packages has created some controversy in the micropaleontological community concerning the use and interpretation of computer-based biofacies discrimination. This is because dramatically different results can be obtained depending on methodology. The analysis of various clustering techniques reveals that, in most instances, no statistical hypothesis is contained in the clustering model and no basis exists for accepting one biofacies partitioning over another. Furthermore, most techniques do not consider standard error in species abundances and generate results that are not statistically relevant. When many rare species are present, statistically insignificant differences in rare species can accumulate and overshadow the significant differences in the major species, leading to biofacies containing members having little in common. A statistically based ''error-weighted maximum likelihood'' (EWML) clustering method is described that determines biofacies by assuming that samples from a common biofacies are normally distributed. Species variability is weighted to be inversely proportional to measurement uncertainty. The method has been applied to samples collected from the Fraser River Delta marsh and shows that five distinct biofacies can be resolved in the data. Similar results were obtained from readily available packages when the data set was preprocessed to reduce the number of degrees of freedom. Based on the sample results from the new algorithm, and on tests using a representative micropaleontological data set, a more conventional iterative processing method is recommended. This method, although not statistical in nature, produces similar results to EWML (not commercially available yet) with readily available analysis packages. Finally, some of the more common clustering techniques are discussed and strategies for their proper utilization are recommended. C1 CARLETON UNIV,OTTAWA CARLETON GEOSCI CTR,OTTAWA K1S 5B6,ONTARIO,CANADA. CARLETON UNIV,DEPT EARTH SCI,OTTAWA K1S 5B6,ONTARIO,CANADA. RP FISHBEIN, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 35 TC 62 Z9 63 U1 1 U2 4 PU PALEONTOLOGICAL SOC INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 SN 0022-3360 J9 J PALEONTOL JI J. Paleontol. PD MAY PY 1993 VL 67 IS 3 BP 475 EP 486 PG 12 WC Paleontology SC Paleontology GA LB687 UT WOS:A1993LB68700012 ER PT J AU SCHMITZ, WJ THOMPSON, JD AF SCHMITZ, WJ THOMPSON, JD TI ON THE EFFECTS OF HORIZONTAL RESOLUTION IN A LIMITED-AREA MODEL OF THE GULF-STREAM SYSTEM SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Note ID MESOSCALE VARIABILITY; BOUNDARY CURRENTS; SEPARATION; SCALE AB An adiabatic, primitive equation, eddy-resolving circulation model has been applied to the Gulf Stream System from Cape Hatteras to east of the Grand Banks (30-degrees-48-degrees-N, 78-degrees-45-degrees-W). A two-layer version of the model was driven both by direct wind forcing and by transport prescribed at inflow ports south of Cape Hatteras for the Gulf Stream and near the Grand Banks of Newfoundland for the deep western boundary current. The mean upper-layer thickness was sufficiently large for interface outcropping not to occur. Numerical experiments previously run at 0.2-degrees horizontal resolution (approximately 20 km) had some realistic features, but a key unresolved deficiency was that the highest eddy kinetic energies obtained near the Gulf Stream were too low relative to data by a factor of about 2, with inadequate eastward penetration. A unique set of new numerical experiments has extended previous results to higher horizontal resolution, all other conditions being held fixed. At 0.1-degrees horizontal resolution, eddy kinetic energies in the vicinity of the Gulf Stream realistically increase by a factor of roughly 2 relative to 0.2-degrees. The increase in eddy activity is a result of enhanced energy conversion from mean flow to fluctuations due to barotropic and baroclinic instabilities, with the nature of the instability mixture as well as eddy energy changing with increased resolution. One experiment at 0.05-degrees horizontal resolution (approximately 5 km) yielded kinetic energies and key energy transfer terms that are within 10% of the equivalent 0.1-degrees case, suggesting that convergence of the numerical solutions has nearly been reached. C1 USN,RES LAB,STENNIS SPACE CTR,DIV OCEAN SENSING & PREDICT,BAY ST LOUIS,MO. RP SCHMITZ, WJ (reprint author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA. NR 22 TC 16 Z9 16 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAY PY 1993 VL 23 IS 5 BP 1001 EP 1007 DI 10.1175/1520-0485(1993)023<1001:OTEOHR>2.0.CO;2 PG 7 WC Oceanography SC Oceanography GA LB822 UT WOS:A1993LB82200014 ER PT J AU MADAVAN, NK RAI, MM GAVALI, S AF MADAVAN, NK RAI, MM GAVALI, S TI MULTIPASSAGE 3-DIMENSIONAL NAVIER-STOKES SIMULATION OF TURBINE ROTOR-STATOR INTERACTION SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID STAGE; FLOW AB This article deals with the development and validation of a three-dimensional, multipassage, Navier-Stokes code for predicting the unsteady effects due to rotor-stator interaction in turbomachines. Prior work in two dimensions has demonstrated the necessity of including multiple rotor and stator passages in order to closely approximate the stator-to-rotor airfoil count ratio, and thus accurately predict the unsteady flowfield resulting from rotor-stator interaction. In this article, this multipassage capability is extended to three dimensions. Numerical results obtained from a multipassage (three stator and four rotor passages) calculation of an axial turbine stage are presented. The stator-to-rotor airfoil count ratio (3:4) used in the present calculations is a close approximation to that in the actual turbine configuration (22:28). The numerical results are compared with experimental data wherever possible and to earlier single-passage calculations. The present multipassage approach results in a more accurate computation of the unsteady flowfield than that possible from a single-passage approach. C1 NASA,AMES RES CTR,DIV FLUID DYNAM,MOFFETT FIELD,CA 94035. FUJITSU AMER INC,SUPERCOMP GRP,SAN JOSE,CA 95134. RP MADAVAN, NK (reprint author), NASA,AMES RES CTR,MCAT INST,M-S 202A-2,MOFFETT FIELD,CA 94035, USA. NR 21 TC 3 Z9 3 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 389 EP 396 DI 10.2514/3.23634 PG 8 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100009 ER PT J AU ANDERSON, BH GIBB, J AF ANDERSON, BH GIBB, J TI STUDY ON VORTEX GENERATOR FLOW-CONTROL FOR THE MANAGEMENT OF INLET DISTORTION SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/SAE/ASME/ASEE 28th Joint Propulsion Conference CY JUL 06-08, 1992 CL NASHVILLE, TN SP AMER INST AERONAUT & ASTRONAUT, SAE, ASME, ASEE AB The present study demonstrates that the reduced Navier-Stokes RNS3D code can be used very effectively to develop a vortex generator installation to minimize the engine face circumferential distortion by controlling secondary flow. The computing times required are small enough that studies such as this are feasible within an analysis-design environment with all its constraints of time and costs. This research study also established the nature of the performance improvements that can be realized with vortex flow control, and suggests a set of aerodynamic properties (called observations) that can be used to arrive at a successful vortex generator installation design. This study also indicated that scaling between flight and typical wind-tunnel test conditions is possible only within a very narrow range of generator configurations close to an optimum installation. Lastly, this study indicated that vortex generator installation design for inlet ducts is more complex than simply satisfying the requirement of attached flow, it must satisfy the requirement of minimum engine face distortion. C1 DEF RES AGCY,BEDFORD,ENGLAND. RP ANDERSON, BH (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 12 TC 8 Z9 10 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 422 EP 430 DI 10.2514/3.23638 PG 9 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100013 ER PT J AU ABDOLHAMID, KS UENISHI, K KEITH, BD CARLSON, JR AF ABDOLHAMID, KS UENISHI, K KEITH, BD CARLSON, JR TI COMMERCIAL TURBOFAN ENGINE EXHAUST NOZZLE-FLOW ANALYSES SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The recently developed three-dimensional code is able to perform a computational investigation of complex aircraft aerodynamic components. This code was developed for solving the simplified Reynolds-averaged Navier-Stokes equations in a three-dimensional multiblock/multizone structured mesh domain. The present analysis was applied to commercial turbofan exhaust flow systems. Solution sensitivity to grid density is presented. Laminar flow solutions were developed for all grids, and two-equation k-epsilon solutions were developed for selected grids. Static pressure distributions, mass flow, and thrust quantities were calculated for on-design engine operating conditions. Good agreement between predicted surface static pressures and experimental data was observed at different locations. Mass flow was predicted within 0.2% of experimental data. Thrust forces were typically within 0.6% of experimental data. C1 ATO GEN ELECTR AIRCRAFT ENGINES,CINCINNATI,OH 45201. NASA,LANGLEY RES CTR,DIV APPL AERODYNAM,PROP AERODYNAM BRANCH,HAMPTON,VA 23665. RP ABDOLHAMID, KS (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 15 TC 4 Z9 5 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 431 EP 436 DI 10.2514/3.23639 PG 6 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100014 ER PT J AU ENGLISH, RE AF ENGLISH, RE TI EVOLVING SP-100 POWERPLANTS VIA ELECTRIC PROPULSION TO GEO AND LUNAR ORBIT SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID PERFORMANCE AB As they contemplate sending personnel on long-term missions to the Moon and Mars, technologists and mission planners are responsible for delineating the costs and risks involved, and for formulating program plans reducing these costs and risks. In this planning, a crucial aspect is program continuity, i.e., the continuing application of a given technology over a long period so that experience will accumulate from extended testing here on Earth and from a diversity of application in space. An integrated view is needed of the missions to be carried out under the space exploration initiative (SEI), near-term as well as far-term, and of the ways in which these missions can mutually support one another. Near-term programs should be constituted to provide both the enabling technologies and the accumulation of experience needed for long-term missions. In achieving this, nuclear-electric propulsion (NEP) missions in Earth orbit should both evolve and demonstrate the technologies crucial to permanent residence on the lunar surface, and the program for the lunar laboratories should evolve and demonstrate the enabling technologies for both exploring the surface of Mars and for flights of human beings to Mars and back. RP ENGLISH, RE (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 449 EP 455 DI 10.2514/3.23642 PG 7 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100017 ER PT J AU MUTHARASAN, R STEINETZ, BM TAO, XM DU, GW KO, F AF MUTHARASAN, R STEINETZ, BM TAO, XM DU, GW KO, F TI DEVELOPMENT OF BRAIDED ROPE SEALS FOR HYPERSONIC ENGINE APPLICATIONS - FLOW MODELING SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A new type of engine seal is being developed to meet the needs of advanced hypersonic engines. A seal braided of emerging high-temperature ceramic fibers comprised of a sheath-core construction has been selected for study based on its low leakage rates. Flexible, low-leakage, high-temperature seals are required to seal the movable engine panels of advanced ramjet-scramjet engines, either preventing potentially dangerous leakage into backside engine cavities or limiting the purge coolant flow rates through the seals. To predict the leakage through these flexible, porous seal structures, new analytical flow models are required. Two such models based on Kozeny-Carman equations are developed herein and are compared to experimental leakage measurements for simulated pressure and seal preload conditions, showing good agreement. The models developed allow prediction of the gas leakage rate as a function of fiber diameter, fiber packing density, gas properties, and pressure drop across the seal. The first model treats the seal as a homogeneous fiber bed. The second model divides the seal into two homogeneous fiber beds identified as the core and the sheath of the seal. C1 NASA,LEWIS RES CTR,STRUCT DYNAM BRANCH,CLEVELAND,OH 44135. RP MUTHARASAN, R (reprint author), DREXEL UNIV,FIBROUS MAT RES CTR,PHILADELPHIA,PA 19104, USA. RI Tao, XiaoMing/A-9992-2010; Mutharasan, Raj/H-2676-2013 OI Tao, XiaoMing/0000-0002-2406-0695; Mutharasan, Raj/0000-0002-3734-5438 NR 9 TC 5 Z9 5 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 456 EP 461 DI 10.2514/3.23643 PG 6 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100018 ER PT J AU TAUBER, ME BOWLES, JV AF TAUBER, ME BOWLES, JV TI PROPELLANT PRODUCTION FROM THE MARTIAN ATMOSPHERE - REPLY SO JOURNAL OF PROPULSION AND POWER LA English DT Letter ID GLOBAL DUST STORMS RP TAUBER, ME (reprint author), NASA,AMES RES CTR,MS 229-3,MOFFETT FIELD,CA 94035, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1993 VL 9 IS 3 BP 495 EP 496 DI 10.2514/3.51371 PG 2 WC Engineering, Aerospace SC Engineering GA LC581 UT WOS:A1993LC58100026 ER PT J AU PRABHAKARA, C KRATZ, DP YOO, JM DALU, G VERNEKAR, A AF PRABHAKARA, C KRATZ, DP YOO, JM DALU, G VERNEKAR, A TI OPTICALLY THIN CIRRUS CLOUDS - RADIATIVE IMPACT ON THE WARM POOL SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID BUDGET EXPERIMENT; CLIMATE; REGION AB Over the convectively active tropical ocean regions, measurements made from space in the infrared (i.r.) and visible have revealed the presence of optically thin cirrus clouds which are quite transparent in the visible and nearly opaque in the infrared. The Nimbus 4 Infrared Interferometer Spectrometer (IRIS), which has a field of view (FOV) of almost-equal-to 100 km, has been utilized to examine the i.r. optical characteristics of these cirrus clouds. From the IRIS data it has been observed that these optically thin cirrus clouds prevail extensively over the ''warm pool'' region of the equatorial western Pacific surrounding Indonesia. It is found that the seasonal cloud cover produced by these thin cirrus exceeds 50% near the central regions of the ''warm pool''. For most of these clouds, optical thickness in the infrared is < 2. It is deduced that dense cold anvil clouds associated with deep convection spread extensively and are responsible for the formation of the thin cirrus. This is supported by the observation that the coverage of the dense anvil clouds is an order of magnitude less than that of the thin cirrus. Observations made by the Earth Radiation Budget Experiment (ERBE) reveal that the ''warm pool'' region constitutes a local maximum in net input of radiative energy. From these observations, together with a simple radiative energy balance model, we have inferred that the greenhouse effect produced by the optically thin cirrus clouds can be a significant factor in maintaining the ''warm pool''. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. APPL RES CORP,LANDOVER,MD 20785. CNR,IST FIS ATMOSFERA,ROME,ITALY. UNIV MARYLAND,DEPT METEOROL,COLL PK,MD 20742. RP PRABHAKARA, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GSFC,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 25 TC 62 Z9 62 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY PY 1993 VL 49 IS 5 BP 467 EP 483 DI 10.1016/0022-4073(93)90061-L PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LB525 UT WOS:A1993LB52500002 ER PT J AU SPENCER, MN CHACKERIAN, C FLANNERY, C STEINFELD, JI AF SPENCER, MN CHACKERIAN, C FLANNERY, C STEINFELD, JI TI TEMPERATURE-DEPENDENCE OF OXYGEN-BROADENING OF OZONE NU(3) ROVIBRATIONAL TRANSITIONS SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID MU-M; AIR; COEFFICIENTS; LINEWIDTHS; REGION; LINES; PARAMETERS; WIDTHS; O-3; N-2 AB We report O2 broadening coefficients for rovibrational transitions in the nu3 band of ozone for temperatures between 165 and 280 K. We assumed a power-law dependence of the temperature for these coefficients, with a temperature exponent n. For the 25 transitions we measured, the average value of gamma0 is 0.071 cm-1 atm-1 and the average for n is 0.67. C1 MIT,DEPT CHEM,CAMBRIDGE,MA 02139. RP SPENCER, MN (reprint author), NASA,AMES RES CTR,ATMOSPHER PHYS RES BRANCH,MOFFETT FIELD,CA 94035, USA. NR 25 TC 11 Z9 11 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY PY 1993 VL 49 IS 5 BP 525 EP 533 PG 9 WC Optics; Spectroscopy SC Optics; Spectroscopy GA LB525 UT WOS:A1993LB52500006 ER PT J AU MCMURTREY, JE CHAPPELLE, EW DAUGHTRY, CST KIM, MS AF MCMURTREY, JE CHAPPELLE, EW DAUGHTRY, CST KIM, MS TI FLUORESCENCE AND REFLECTANCE OF CROP RESIDUE AND SOIL SO JOURNAL OF SOIL AND WATER CONSERVATION LA English DT Article ID LASER-INDUCED FLUORESCENCE; GREEN PLANTS; BLUE FLUORESCENCE; COVER; SPECTROSCOPY AB An assessment of fluorescence and reflectance sensing technology for detecting crop residues from soils was conducted under laboratory conditions. Residue samples from five crop species (corn, cotton, peanut, soybean, and wheat) and four soils with different color and albedo were tested. The studies were conducted under wet and dry conditions. Residues bad consistently higher fluorescence emission in a band from 415-550 nm than did soils. Reflectance of the same materials indicated that certain residues can be distinguished from certain soils. Many crop residues were significantly higher or lower in reflectance than several soils. Other residues and soils could not be readily distinguished from each other on the basis of a single reflectance band. Nevertheless, discrimination of many crop residues from soil by reflectance could be possible by calibrating the threshold of discrimination for each soil and crop residue combination. A vegetation index, calculated from integrations of red and near infrared reflectance wavelengths, simulating the bands used on the current Landsat remote sensing satellite was also effective in distinguishing differences between many residue/soil combinations. Reflectance data simulating TM3 (630-690 nm) and TM4 (760-900 nm) Landsat satellite bands are reported. other bands could be amenable to reflectance detection as well. These initial studies suggest that fluorescence and reflectance sensing techniques for determining crop residue coverage are feasible and should be developed further. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP MCMURTREY, JE (reprint author), USDA ARS, BELTSVILLE AGR RES CTR, BELTSVILLE, MD 20705 USA. NR 21 TC 34 Z9 34 U1 0 U2 4 PU SOIL WATER CONSERVATION SOC PI ANKENY PA 945 SW ANKENY RD, ANKENY, IA 50023-9723 USA SN 0022-4561 EI 1941-3300 J9 J SOIL WATER CONSERV JI J. Soil Water Conserv. PD MAY-JUN PY 1993 VL 48 IS 3 BP 207 EP 213 PG 7 WC Ecology; Soil Science; Water Resources SC Environmental Sciences & Ecology; Agriculture; Water Resources GA LB837 UT WOS:A1993LB83700007 ER PT J AU JAIN, RK FLOOD, DJ AF JAIN, RK FLOOD, DJ TI MONOLITHIC AND MECHANICAL MULTIJUNCTION SPACE SOLAR-CELLS SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB High-efficiency, lightweight, radiation-resistant solar cells are essential to meet the large power requirements of future space missions. Single-junction cells are limited in efficiency. Higher cell efficiencies could be realized by developing multijunction, multibandgap solar cells. Monolithic and mechanically stacked tandem solar cells surpassing single-junction cell efficiencies have been fabricated. This article surveys the current status of monolithic and mechanically stacked multibandgap space solar cells, and outlines problems yet to be resolved. The monolithic and mechanically stacked cells each have their own problems related to size, processing, current and voltage matching, weight, and other factors. More information is needed on the effect of temperature and radiation on the cell performance. Proper reference cells and full-spectrum range simulators are also needed to measure efficiencies correctly. Cost issues are not addressed, since two approaches are still in the developmental stage. RP JAIN, RK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 26 TC 6 Z9 6 U1 1 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD MAY PY 1993 VL 115 IS 2 BP 106 EP 111 DI 10.1115/1.2930027 PG 6 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA LD992 UT WOS:A1993LD99200007 ER PT J AU HOLLOWAY, PF AF HOLLOWAY, PF TI AND A WARM WELCOME SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material RP HOLLOWAY, PF (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 257 EP 257 DI 10.2514/3.55657 PG 1 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800002 ER PT J AU ZOBY, EV AF ZOBY, EV TI A THANK-YOU AND A REFLECTION SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material RP ZOBY, EV (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 257 EP 257 DI 10.2514/3.55656 PG 1 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800001 ER PT J AU KERSLAKE, WR IGNACZAK, LR AF KERSLAKE, WR IGNACZAK, LR TI DEVELOPMENT AND FLIGHT HISTORY OF THE SERT-II SPACECRAFT SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article RP KERSLAKE, WR (reprint author), NASA,LEWIS RES CTR,FLIGHT PROJECTS BRANCH,CLEVELAND,OH 44135, USA. NR 100 TC 8 Z9 8 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 258 EP 290 DI 10.2514/3.25512 PG 33 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800003 ER PT J AU HUEBNER, LD UTREJA, LR AF HUEBNER, LD UTREJA, LR TI MACH-10 BOW-SHOCK BEHAVIOR OF A FORWARD-FACING NOSE CAVITY SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A detailed description of the bow-shock behavior associated with a conical-walled cavity with a flat circular base at M(infinity) = 10 is presented. An experimental test was performed on this configuration, and measurements of shock-oscillation frequency and amplitude, as well as shock shape, were recorded by a number of techniques, one being a laser-interferometer system used for the first time during this test to determine bow-shock oscillation frequency in a nonintrusive manner. The primary behavior was a stable, periodically oscillating bow shock. Discussions are also made on a violent bow-shock instability that occurred for one set of conditions during the test. C1 DYNACS ENGN CO INC,HUNTSVILLE DIV,HUNTSVILLE,AL 35806. RP HUEBNER, LD (reprint author), NASA,LANGLEY RES CTR,DIV APPL AERODYNAM,SUPERSON HYPERSON AERODYNAM BRANCH,HYPERSON GRP,HAMPTON,VA 23665, USA. NR 15 TC 16 Z9 17 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 291 EP 297 DI 10.2514/3.25513 PG 7 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800004 ER PT J AU CARRUTH, MR VAUGHN, JA BECHTEL, RT GRAY, PA AF CARRUTH, MR VAUGHN, JA BECHTEL, RT GRAY, PA TI EXPERIMENTAL STUDIES ON SPACECRAFT ARCING SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Space Station Freedom (SSF) will be the largest and highest powered spacecraft put into orbit. Because of the balance of leakage currents through the ambient ionospheric plasma, the structure will be driven approximately 140 V negative of the ambient plasma without a plasma contractor for negative control. Surface materials such as anodized aluminum will have the entire voltage dropped across a thin dielectric that may not have sufficient dielectric strength to prevent dielectric breakdown. The results of experiments done to measure the dielectric breakdown threshold of anodized aluminum with a range of anodization thicknesses designed to span a range of thermal control properties being considered for SSF show breakdown thresholds near -90 V in an argon plasma with densities comparable to that of low-Earth orbit. Because of the size of Space Station Freedom, the thin anodization layer can store large amounts of charge. Experiments done to simulate the discharge of these large capacitances indicated currents as large as 1000 A are possible, and observations of the anodization surface show the energy released in these high-current arcs produced craters through the anodic coating to the bare aluminum. The debris from the craters produces a contamination source for sensitive surfaces. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ELECT POWER BRANCH,HUNTSVILLE,AL 35812. SVERDRUP TECHNOL,DEPT MAT & PROC,HUNTSVILLE,AL 35806. RP CARRUTH, MR (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PHYS SCI BRANCH,HUNTSVILLE,AL 35812, USA. NR 17 TC 10 Z9 10 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 323 EP 327 DI 10.2514/3.25517 PG 5 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800008 ER PT J AU SUSKO, M AF SUSKO, M TI TURBULENCE INDICATORS FOR SPACE-SHUTTLE LAUNCHES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The primary objective of this paper is to report on the research and analysis on identifying turbulent regions from the surface to 16 km for Space Shuttle launches. This research has demonstrated that the results from the FPS-16 radar/Jimsphere balloon system in measuring winds can indeed indicate the presence or conditions ripe for turbulence in the troposphere and lower stratosphere. It is further demonstrated that atmospheric data obtained during the shuttle launches by the rawinsonde in conjunction with the Jimsphere provides the necessary meteorological data to compute aerodynamic parameters to identify turbulence such as Reynolds number, drag coefficient, turbulent stresses, stability parameter, vertical gradient (turbulence), Richardson number, and the turbulence probability index. These turbulence indicators were computed from 16 Jimsphere balloon releases obtained during Space Shuttle launches at KSC and presented in Table 1. Two of the launches, STS-11 and STS-41D, illustrating examples of turbulence (T) and no turbulence (NT) in the atmosphere are displayed from Table 1. There is no magic foolproof criteria in atmospheric turbulent probability of occurrence. However, enhanced temperature lapse rates and inversion rates, strong vector wind shears, and large changes in wind direction identify the occurrence of turbulence at the tropopause. When any two of the above conditions occur simultaneously, a significant probability of turbulence can occur as shown in the paper. RP SUSKO, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ENVIRONM ANAL BRANCH,HUNTSVILLE,AL 35812, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 328 EP 333 DI 10.2514/3.25518 PG 6 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800009 ER PT J AU BYRNES, DV LONGUSKI, JM ALDRIN, B AF BYRNES, DV LONGUSKI, JM ALDRIN, B TI CYCLER ORBIT BETWEEN EARTH AND MARS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID TRAJECTORY OPTIMIZATION AB A periodic orbit between Earth and Mars has been discovered that, after launch, permits a space vehicle to cycle back and forth between the planets with moderate maneuvers at irregular intervals. A space station placed in this cycler orbit could provide a safe haven from radiation and comfortable living quarters for astronauts en route to Earth or Mars. The orbit is largely maintained by gravity assist from Earth. Numerical results from multiconic optimization software are presented for a 15-year period from 1995 through 2010. C1 PURDUE UNIV,SCH AERONAUT & ASTRONAUT,W LAFAYETTE,IN 47907. RP BYRNES, DV (reprint author), JET PROP LAB,MIS DESIGN SECT,PASADENA,CA 91109, USA. NR 13 TC 50 Z9 51 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 334 EP 336 DI 10.2514/3.25519 PG 3 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800010 ER PT J AU WILFONG, TL SMITH, SA CREASEY, RL AF WILFONG, TL SMITH, SA CREASEY, RL TI HIGH TEMPORAL RESOLUTION VELOCITY ESTIMATES FROM A WIND PROFILER SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Existing techniques for rejecting spurious data in single-cycle wind profiles employ a consensus average method to several profiles. This technique sometimes fails and also severely limits temporal resolution. The authors find by first applying a median filter to three successive single-cycle (3 min) spectral data and then guiding the velocity calculation by a first guess, it is possible to extract high-quality wind profiles at 3-min intervals. For support to launch operations, it is critical the wind-profile data be correct. The authors introduce an interactive quality control methodology in which the median spectral data are overlaid with the computed velocity profile. Two test cases are presented. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP WILFONG, TL (reprint author), UNIV ALABAMA,SPACE RES ASSOC,4950 CORP DR,SUITE 100,HUNTSVILLE,AL 35806, USA. NR 4 TC 14 Z9 14 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 348 EP 354 DI 10.2514/3.25522 PG 7 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800013 ER PT J AU ALFANO, S NEGRON, D AF ALFANO, S NEGRON, D TI COMPLETE METHOD OF RATIOS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper outlines two algorithms to compute the average daily access time of a space object by a ground station with restrictions in azimuth, elevation, and range. The first technique, entitled the complete method of ratios, makes extensive use of spherical trigonometry to arrive at a viewing solution whereas the second technique, entitled multiple antennas, uses site topocentric pointing information to determine access time. For the first technique, the original method of ratios is expanded to include viewing restrictions in azimuth and elevation. Simulation results for both methods are documented for a fictitious site restricted to 3500 km range visibility, with seven pairs of azimuth and elevation restrictions. For this study, orbital motion is modeled with J2 effects, and a viewing solution truth table is created from a 5 s sequential step. Test results include site latitude variations as well as computer run time comparisons to illustrate the execution performance of each technique. The methods presented here are useful tools for mission planners to rapidly evaluate all objects in a space catalog and maintain a current database of objects that are visible to a particular ground station. C1 US SPACE COMMAND,DIV SPACE CONTROL OPERAT,CHEYENNE MT AFB,CO 80914. RP ALFANO, S (reprint author), PHILLIPS LAB,VTA,PL,DIV MISSILES DYNAM,KIRTLAND AFB,NM 87117, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 374 EP 379 DI 10.2514/3.25525 PG 6 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800016 ER PT J AU STRAWA, AW DAVY, WC KRUSE, R AF STRAWA, AW DAVY, WC KRUSE, R TI MEASUREMENTS IN THE WAKE OF BLUNT AEROBRAKE MODELS AT 1.8 AND 4.9 KM/S SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 ELORET INST,PALO ALTO,CA 94303. RP STRAWA, AW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 380 EP 382 DI 10.2514/3.25526 PG 3 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800017 ER PT J AU STRAWA, AW PARK, C DAVY, WC CRAIG, RA BABIKIAN, DS PRABHU, DK VENKATAPATHY, E AF STRAWA, AW PARK, C DAVY, WC CRAIG, RA BABIKIAN, DS PRABHU, DK VENKATAPATHY, E TI PROPOSED RADIOMETRIC MEASUREMENT OF THE WAKE OF A BLUNT AEROBRAKE (VOL 29, PG 765, 1992) SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Correction, Addition C1 ELORET INST,PALO ALTO,CA 94303. RP STRAWA, AW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1993 VL 30 IS 3 BP 384 EP 384 DI 10.2514/3.55658 PG 1 WC Engineering, Aerospace SC Engineering GA LG868 UT WOS:A1993LG86800019 ER PT J AU BONACUSE, PJ KALLURI, S AF BONACUSE, PJ KALLURI, S TI AXIAL-TORSIONAL FATIGUE - A STUDY OF TUBULAR SPECIMEN THICKNESS EFFECTS SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE FATIGUE; MULTIAXIAL; IN-PHASE; OUT-OF-PHASE; TUBULAR SPECIMEN; STAINLESS STEEL AB A room-temperature experimental program was conducted on AISI type 316 stainless steel to determine the effect of wall thickness on the cyclic deformation behavior and fatigue life of thin-wall, tubular, axial-torsional fatigue specimens. The following experimental variables were examined in this study: the depth of the surface work-hardened layer produced in specimen machining, and the effects of strain range and axial-torsional strain phasing. Tubular fatigue specimens were fabricated with wall thicknesses of 1.5, 2.0, and 2.5 mm. One as-fabricated specimen from each wall thickness was sectioned for microstructural examination and microhardness measurement. A specimen of each wall thickness was tested at each of three conditions-high strain range in-phase, low strain range in-phase, and low strain range out-of-phase-for a total of nine axial-torsional fatigue experiments. Little or no variation in the fatigue life or deformation behavior as a function of wall thickness was observed. The machining-induced work-hardened zone, as a percentage of the gage section material, was found to have a minimal effect on both deformation behavior and fatigue life. Out-of-phase fatigue tests displayed shorter fatigue lives and more cyclic hardening than in-phase tests. C1 NASA LEWIS RES CTR GRP,SVERDRUP TECHNOL INC,CLEVELAND,OH 44135. RP BONACUSE, PJ (reprint author), NASA,LEWIS RES CTR,USA,RES LAB,VEHICLE PROPULS DIRECTORATE,CLEVELAND,OH 44135, USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAY PY 1993 VL 21 IS 3 BP 160 EP 167 PG 8 WC Materials Science, Characterization & Testing SC Materials Science GA KY283 UT WOS:A1993KY28300003 ER PT J AU NGO, KCT ZUCKERWAR, AJ AF NGO, KCT ZUCKERWAR, AJ TI ACOUSTIC ISOLATION VESSEL FOR MEASUREMENT OF THE BACKGROUND-NOISE IN MICROPHONES SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB An acoustic isolation vessel has been developed to measure the background noise in microphones. The test microphone is installed in an inner vessel, which is suspended within an outer vessel, and the intervening air space is evacuated to a high vacuum. An analytical expression for the transmission coefficient is derived, based on a five-media model, and compared to experiment. At an isolation vacuum of 5 X 10(-6) Torr the experimental transmission coefficient was found to be lower than - 155 dB at frequencies ranging from 40 to 1200 Hz. Measurements of the A-weighted noise levels of commercial condenser microphones of four different sizes show good agreement with published values. C1 OLD DOMINION UNIV,NORFOLK,VA 23508. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 7 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAY PY 1993 VL 93 IS 5 BP 2974 EP 2980 DI 10.1121/1.405816 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA LC572 UT WOS:A1993LC57200053 ER PT J AU BANSAL, NP DRUMMOND, CH AF BANSAL, NP DRUMMOND, CH TI KINETICS OF HEXACELSIAN-TO-CELSIAN PHASE-TRANSFORMATION IN SRAL2SI2O8 SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT A R COOPER SYMP ON GLASS SCIENCE AND TECHNOLOGY, AT THE 1992 ANNUAL MEETING OF THE AMERICAN CERAMIC SOC CY APR 13-14, 1992 CL MINNEAPOLIS, MN SP AMER CERAM SOC AB The kinetics of hexacelsian-to-celsian phase transformation in SrAl2Si2O8 have been investigated. Phase-pure hexacelsian was prepared by heat treatment of glass flakes at 990-degrees-C for 10 h. Hexacelsian flakes were isothermally heat-treated at 1026-degrees, 1050-degrees, 1100-degrees, 1152-degrees, and 1200-degrees-C for various times. The amounts of monoclinic celsian formed were determined using quantitative X-ray diffraction. Values of reaction rate constant, k, at various temperatures were evaluated from the Avrami equation. The Avrami parameter was determined to be 1.1, suggesting one-dimensional growth with the interface rather than a diffusion-controlled transformation mechanism. From the temperature dependence of k, the apparent activation energy for this reaction was evaluated to be 527 +/- 50 kj mol (126 +/- 12 kcal mol). This value is consistent with a mechanism involving the transformation of the layered hexacelsian structure to a three-dimensional network celsian structure which necessitates breaking of the strongest bonds, the Si-O bonds. C1 OHIO STATE UNIV,DEPT MAT SCI & ENGN,COLUMBUS,OH 43210. RP BANSAL, NP (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 8 TC 46 Z9 47 U1 0 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1993 VL 76 IS 5 BP 1321 EP 1324 DI 10.1111/j.1151-2916.1993.tb03758.x PG 4 WC Materials Science, Ceramics SC Materials Science GA LZ285 UT WOS:A1993LZ28500037 ER PT J AU GONG, R LINDBERG, J ABRAMS, J WHITAKER, WR WADE, CE GOUGE, S AF GONG, R LINDBERG, J ABRAMS, J WHITAKER, WR WADE, CE GOUGE, S TI COMPARISON OF HYPERTONIC SALINE SOLUTIONS AND DEXTRAN IN DIALYSIS-INDUCED HYPOTENSION SO JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY LA English DT Article DE HYPOTENSION; DEXTRAN; HEMODIALYSIS; HYPERTONIC ID HEMODIALYSIS; INSTABILITY; NACL AB The efficacy of three hypertonic saline solutions for treating dialysis-induced hypotension in a randomized, blinded, crossover clinical trial of 10 patients (a minimum of three cycles per solution) was compared. Dialysis-induced hypotension, defined as a decrease in systolic blood pressure of at least 10 mm Hg or systolic blood pressure less than 100 mm Hg, was treated with an iv bolus of either 10 mL of 23% saturated hypertonic saline, 30 mL of 7.5% hypertonic saline, or 30 mL of 7.5% saline with 6% dextran 70, each containing similar osmolar loads of 80, 80, and 100 mosM, respectively. All three solutions raised systolic blood pressure within 5 min (mean pretreatment systolic blood pressure, 87 mm Hg; mean posttreatment systolic blood pressure, 101 mm Hg; P< 0.05). The magnitude of the increase was greater with saturated hypertonic saline (15 mm Hg) and dextran 70 (17 mm Hg) compared with that with hypertonic saline (9 mm Hg; P < 0.05). At 10 min, dialysis-induced hypotension was less frequent with saturated hypertonic saline (incidence, 9%) compared with hypertonic saline (45%). Beyond 10 min, however, there was a trend toward a lower incidence of further dialysis-induced hypotension with dextran 70. There were no side effects. Given equal osmole loads, the more concentrated solution produced a greater increase in systolic blood pressure. The addition of an oncotic agent such as dextran may prolong the blood pressure response beyond 10 min. It was concluded that hypertonic saline solutions safely and effectively treat dialysis-induced hypotension. C1 ALTON OCHSNER MED FDN & OCHSNER CLIN,DEPT NEPHROL,1514 JEFFERSON HIGHWAY,NEW ORLEANS,LA 70121. LETTERMAN ARMY MED CTR,SAN FRANCISCO,CA 94129. ALTON OCHSNER MED FDN & OCHSNER CLIN,NEW ORLEANS,LA 70121. WILLIAM BEAUMONT ARMY MED CTR,EL PASO,TX 79920. WALTER REED ARMY MED CTR,WASHINGTON,DC 20307. NASA,AMES RES CTR,DEPT LIFE SCI,MOFFETT FIELD,CA 94035. BROOK ARMY MED CTR,FT SAM HOUSTON,TX. NR 14 TC 13 Z9 13 U1 0 U2 0 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 1046-6673 J9 J AM SOC NEPHROL JI J. Am. Soc. Nephrol. PD MAY PY 1993 VL 3 IS 11 BP 1808 EP 1812 PG 5 WC Urology & Nephrology SC Urology & Nephrology GA LF381 UT WOS:A1993LF38100010 PM 7687157 ER PT J AU MINNIS, P LIOU, KN TAKANO, Y AF MINNIS, P LIOU, KN TAKANO, Y TI INFERENCE OF CIRRUS CLOUD PROPERTIES USING SATELLITE-OBSERVED VISIBLE AND INFRARED RADIANCES .1. PARAMETERIZATION OF RADIANCE FIELDS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SOLAR RADIATIVE-TRANSFER; OPTICAL-PROPERTIES; SINGLE-SCATTERING; TROPICAL CIRRUS; REMOTE; ABSORPTION; COVER; LIDAR; TEMPERATURE; ATMOSPHERE AB Current techniques for deriving cirrus optical depth and altitude from visible (0.65 mum) and infrared (11.5 mum) satellite data use radiative transfer calculations based on scattering phase functions of spherical water droplets. This study examines the impact of using phase functions for spherical droplets and hexagonal ice crystals to analyze radiances from cirrus. Adding-doubling radiative transfer calculations are used to compute radiances for different cloud thicknesses and heights over various backgrounds. These radiances are used to develop parameterizations of top-of-the-atmosphere visible reflectance and infrared emittance utilizing tables of reflectance as a function of cloud optical depth, viewing and illumination angles, and microphysics. This parameterization, which includes Rayleigh scattering, ozone absorption, variable cloud height, and an anisotropic surface reflectance, reproduces the computed top-of-the-atmosphere reflectances with an accuracy of +/-6% for four microphysical models: 10-mum water droplet, small symmetric crystal, cirrostratus, and cirrus uncinus. The accuracy is twice that of previous models. Bidirectional reflectance patterns from theoretical ice-crystal clouds are distinctly different from those of the theoretical water-droplet clouds. In general, the ice-crystal phase functions produce significantly larger reflectances than the water-droplet phase function for a given optical depth. A parameterization relating infrared emittance to visible optical depth is also developed. The effective infrared emittances computed with the adding-doubling method are reproduced with a precision of +/-2%. Infrared scattering reduces emittance by an average of 5%. Simulated cloud retrievals using the parameterization indicate that optical depths and cloud temperatures can be determined with an accuracy of approximately 25% and approximately 6 K for typical cirrus conditions. Retrievals of colder clouds over brighter surfaces are not as accurate, while those of warmer clouds over dark surfaces will be more reliable. Sensitivity analyses show that the use of the water-droplet phase function to interpret radiances from a theoretical cirrostratus cloud will significantly overestimate the optical depth and underestimate cloud height by 1.5-2.0 km for nominal cirrus clouds (temperature of 240 K and visible optical depth of approximately 1). The parameterization developed here is economical in terms of computer memory and is useful for both simulation and interpretation of cloud radiance fields. C1 UNIV UTAH,DEPT METEOROL,SALT LAKE CITY,UT 84112. RP MINNIS, P (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 420,21 AMES RD,HAMPTON,VA 23681, USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 46 TC 119 Z9 122 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 1 PY 1993 VL 50 IS 9 BP 1279 EP 1304 DI 10.1175/1520-0469(1993)050<1279:IOCCPU>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LB645 UT WOS:A1993LB64500010 ER PT J AU MINNIS, P HECK, PW YOUNG, DF AF MINNIS, P HECK, PW YOUNG, DF TI INFERENCE OF CIRRUS CLOUD PROPERTIES USING SATELLITE-OBSERVED VISIBLE AND INFRARED RADIANCES .2. VERIFICATION OF THEORETICAL CIRRUS RADIATIVE PROPERTIES SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SINGLE-SCATTERING; PROJECT; PHASE; FIRE AB A methodology is developed to apply a parameterization of radiative transfer calculations to satellite analyses of cirrus clouds. Cloud heights and optical depths are derived from visible and infrared window measurements taken during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) when cirrus clouds were present. Geostationary satellite retrievals are compared to lidar-derived cloud heights and retrievals from a polar-orbiting satellite taken at different angles to determine which theoretical models of scattering phase function and single-scattering albedo best represent actual cirrus clouds. Models using small hexagonal ice crystals with a diameter of 20 mum (C20) and a size distribution of slightly larger hexagonal ice crystals representing a cirrostratus (CS) cloud produce the best results. The resulting mean cloud heights are within +/-0.3 km of the lidar results and have instantaneous uncertainties of +/-1.3 km. Mean cloud heights derived using a model based on water droplets with a 10-mum effective radius (ID) and a model based on a distribution of large ice crystals (cirrus uncinus, CU) are 1.3 km less than the lidar heights. The cloud height biases are due to overestimates of the cloud optical depths that are as much as 1.7 times greater than the C20 values. Reflectance patterns computed with the ice crystal models are consistent with the dual-satellite, multiangle observations of optical depth. Of the three ice-crystal models, the C20 model produced the least bias (3%), while the CU model yielded the greatest (12%). The ID-model optical depths derived using the geostationary satellite were 67% less than those from the polar-orbiting satellite. It is concluded that interpretation of cirrus reflectance with water-droplet models leads to biased results. This finding has important implications for the cirrus cloud properties derived by the ISCCP. The cloud-height and optical depth biases can be minimized with the use of the C20 or CS models. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA. RP MINNIS, P (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23681, USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 20 TC 116 Z9 119 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 1 PY 1993 VL 50 IS 9 BP 1305 EP 1322 DI 10.1175/1520-0469(1993)050<1305:IOCCPU>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA LB645 UT WOS:A1993LB64500011 ER PT J AU MATSON, DM LANSAW, JT SUITS, MW ROSE, AW DANEK, P NELLIGAN, TJ MOONEY, PP AF MATSON, DM LANSAW, JT SUITS, MW ROSE, AW DANEK, P NELLIGAN, TJ MOONEY, PP TI ULTRASONIC INSPECTION OF A DIFFUSION-BONDED PLATELET ROCKET CHAMBER LINER SO MATERIALS EVALUATION LA English DT Article C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,NDE BRANCH,HUNTSVILLE,AL 35812. AEROJET PROPULS DIV,SACRAMENTO,CA 95813. PANAMETRICS INC,DIV NDT,WALTHAM,MA 02154. RP MATSON, DM (reprint author), AEROJET,DIV PROP,700 BLVD S,SUITE 301,HUNTSVILLE,AL 35802, USA. RI Matson, Douglas/I-7860-2015 NR 9 TC 2 Z9 2 U1 2 U2 2 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAY PY 1993 VL 51 IS 5 BP 545 EP & PG 0 WC Materials Science, Characterization & Testing SC Materials Science GA LB901 UT WOS:A1993LB90100004 ER PT J AU BARCOHEN, Y AF BARCOHEN, Y TI THE JET PROPULSION LABORATORYS NDE TECHNOLOGY-TRANSFER AND COMMERCIALIZATION INITIATIVE SO MATERIALS EVALUATION LA English DT Article RP BARCOHEN, Y (reprint author), JET PROP LAB,MAT ENGN GRP,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAY PY 1993 VL 51 IS 5 BP 578 EP 578 PG 1 WC Materials Science, Characterization & Testing SC Materials Science GA LB901 UT WOS:A1993LB90100008 ER PT J AU BRINDLEY, WJ WHITTENBERGER, JD AF BRINDLEY, WJ WHITTENBERGER, JD TI STRESS-RELAXATION OF LOW-PRESSURE PLASMA-SPRAYED NICRALY ALLOYS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID THERMAL BARRIER COATINGS AB The stress relaxation behavior of three NiCrAlY alloys that are commonly used as bond coats for thermal barrier coatings (TBCs) has been directly measured. The relaxation study was conducted at temperatures of 800-1000-degrees-C and over a wide range of stresses. It was established that all three bond coat alloys relaxed quite rapidly at temperatures of 900-degrees-C and above. Since the upper use temperatures for bond coats in gas turbine engines are between 900 and 1000-degrees-C, bond coat relaxation is expected to occur in service. Therefore, relaxation of the bond coat has the potential to affect TBC life. Furthermore, the relaxation differences observed between the three alloys offers a possible explanation for the differences in TBC life observed for these bond coats. While bond coat relaxation is expected to occur for a TBC in service, the mechanism for a relaxation effect on TBC life, if it exists, is yet to be determined. RP BRINDLEY, WJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 13 TC 41 Z9 41 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 1 PY 1993 VL 163 IS 1 BP 33 EP 41 DI 10.1016/0921-5093(93)90575-Y PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA LF639 UT WOS:A1993LF63900004 ER PT J AU MYBURGH, KH CHARETTE, S ZHOU, LJ STEELE, CR ARNAUD, S MARCUS, R AF MYBURGH, KH CHARETTE, S ZHOU, LJ STEELE, CR ARNAUD, S MARCUS, R TI INFLUENCE OF RECREATIONAL ACTIVITY AND MUSCLE STRENGTH ON ULNAR BENDING STIFFNESS IN MEN SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE MECHANICAL IMPEDANCE; BICEPS STRENGTH; GRIP STRENGTH; ULNA WIDTH ID BONE-MINERAL DENSITY; BODY-COMPOSITION; AGE; WOMEN; MASS; WEIGHT AB Bone bending stiffness (modulus of elasticity [E] x moment of inertia [I]), a measure of bone strength, is related to its mineral content (BMC) and geometry and may be influenced by exercise. We evaluated the relationship of habitual recreational exercise and muscle strength to ulnar EI, width, and BMC in 51 healthy men, 28-61 yr of age. BMC and width were measured by single photon absorptiometry and EI by mechanical resistance tissue analysis. Maximum biceps strength was determined dynamically (1-RM) and grip strength isometrically. Subjects were classified as sedentary (S) (N = 13), moderately (M) (N = 18), or highly active (H) (N = 20) and exercised 0.2 +/- 0.2; 2.2 +/- 1.3; and 6.8 +/- 2.3 h . wk-1 (P < 0.001). H had greater biceps (P < 0.0005) and grip strength (P < 0.05), ulnar BMC (P < 0.05), and ulnar EI (P = 0.01) than M or S, who were similar. Amount of activity correlated with grip and biceps strength (r = 0.47 and 0.49; P < 0.001), but not with bone measurements, whereas muscle strength correlated with both EI and BMC (r = 0.40-0.52, P < 0.005). EI also correlated significantly with both BMC and ulnar width (P < 0.0001). Ulnar width and biceps strength were the only independent predictors of EI (r2 = 0.67, P < 0.0001). We conclude that levels of physical activity sufficient to increase arm strength influence ulnar bending stiffness. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. STANFORD UNIV,DEPT MED,STANFORD,CA 94305. STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. OI Myburgh, Kathryn/0000-0003-4501-2120 NR 27 TC 24 Z9 25 U1 0 U2 0 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 1993 VL 25 IS 5 BP 592 EP 596 PG 5 WC Sport Sciences SC Sport Sciences GA LA333 UT WOS:A1993LA33300009 PM 8492687 ER PT J AU JACOBSON, NS OPILA, EJ AF JACOBSON, NS OPILA, EJ TI THERMODYNAMICS OF SI-C-O SYSTEM SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Note ID METALLIC SILICON; CARBIDE C1 CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115. RP JACOBSON, NS (reprint author), NASA,LEWIS RES CTR,DIV MAT,ENVIRONM DURABIL BRANCH,CLEVELAND,OH 44135, USA. RI Jacobson, Nathan/A-9411-2009 NR 15 TC 16 Z9 16 U1 0 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD MAY PY 1993 VL 24 IS 5 BP 1212 EP 1214 DI 10.1007/BF02657254 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA LA785 UT WOS:A1993LA78500024 ER PT J AU DIB, NI DRAYTON, RF KATEHI, LPB AF DIB, NI DRAYTON, RF KATEHI, LPB TI A THEORETICAL AND EXPERIMENTAL-STUDY OF MICROSHIELD CIRCUITS SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article DE MONOLITHIC TRANSMISSION LINE; PLANAR DISCONTINUITIES; INTEGRAL EQUATION; COPLANAR WAVE-GUIDE; RADIATION LOSS AB A theoretical and experimental study of a new type of monolithic planar transmission line is presented. This line can operate without the need for via holes or the use of air bridges for ground equalization. Furthermore, it has shown the tendency to radiate less than the conventional coplanar waveguide (CPW) and can provide a wide range of impedances due to the many available parameters for design. The space-domain integral equation method is used to analyze several discontinuities of the proposed line. In order to validate the theory, measurements are performed on scaled models of a specific discontinuity. The experimental and theoretical results are in good agreement. In addition, it is demonstrated that the proposed line discontinuities radiate considerably less than the corresponding co-planar waveguide ones. RP DIB, NI (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ,ANN ARBOR,MI 48109, USA. RI Franklin, Rhonda/C-8037-2011; Dib, Nihad/M-4918-2015; OI Dib, Nihad/0000-0002-2263-5512 NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD MAY PY 1993 VL 6 IS 6 BP 333 EP 339 DI 10.1002/mop.4650060602 PG 7 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA KX363 UT WOS:A1993KX36300001 ER PT J AU THATCHER, JD ROBINSON, RD AF THATCHER, JD ROBINSON, RD TI THE CHROMOSPHERES OF LATE-TYPE STARS .2. AN ATLAS OF CHROMOSPHERIC LINES FOR SELECTED EARLY-K STARS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE LINE-PROFILES; STARS-ACTIVITY; STARS-CHROMOSPHERES; STARS-LATE-TYPE ID STELLAR MODEL CHROMOSPHERES; CA-II-H; MAIN-SEQUENCE STARS; SOLAR-TYPE STARS; LATE-TYPE DWARFS; ALPHA EMISSION; COOL STARS; MAGNETIC-STRUCTURE; QUIESCENT DWARFS; EPSILON-ERIDANI AB For 22 early-K stars, we present high-resolution spectra (lambda/DELTAlambda), = 55 000) of the chromospheric Na I D lines, Ca I lambda4227, Mg I lambdalambda4571, 5167 and 5172, the Ca II H and K resonance and IR lambdalambda8542.144 and 8662.170 lines, Halpha and Hbeta, all observed simultaneously at the AAT, and thus add to a growing data base of spectra of late-type stars. Our data are presented as the observational basis for the self-consistent, semi-empirical modelling of the outer photospheres and chromospheres of the target stars. From trends in our data, we find that stellar activity shows in the low-chromosphere lines as core-filling and, in some stars, as line-broadening. We derive integrated fluxes from the difference spectra, formed by subtracting quiet from active spectra, in the Ca II H and K resonance and IR lambdalambda8542 and 8662 lines and in Halpha, which are presented as chromospheric activity indicators. To these we add the equivalent widths, and the core depths of Halpha and Hbeta, as further indicators. All the activity indices show strong correlations, with the exception of the equivalent widths of Halpha and Hbeta, which we find to be relatively poor activity discriminators. We also find the Balmer decrement to be a useful (and apparently neglected) activity indicator. C1 NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, ASTRON PROGRAM, GREENBELT, MD 20771 USA. ANGLO AUSTRALIAN OBSERV, EPPING, NSW 2121, AUSTRALIA. RP UNIV SYDNEY, SCH MATH & STAT, SYDNEY, NSW 2006, AUSTRALIA. NR 76 TC 27 Z9 27 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 1993 VL 262 IS 1 BP 1 EP 19 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KZ987 UT WOS:A1993KZ98700005 ER PT J AU BALDI, P CHAUVIN, Y AF BALDI, P CHAUVIN, Y TI NEURAL NETWORKS FOR FINGERPRINT RECOGNITION SO NEURAL COMPUTATION LA English DT Letter AB After collecting a data base of fingerprint images, we design a neural network algorithm for fingerprint recognition. When presented with a pair of fingerprint images, the algorithm outputs an estimate of the probability that the two images originate from the same finger. In one experiment, the neural network is trained using a few hundred pairs of images and its performance is subsequently tested using several thousand pairs of images originated from a subset of the data base corresponding to 20 individuals. The error rate currently achieved is less than 0.5%. Additional results, extensions, and possible applications are also briefly discussed. C1 CALTECH,DIV BIOL,PASADENA,CA 91109. NET ID INC,STANFORD,CA 94305. STANFORD UNIV,DEPT PSYCHOL,STANFORD,CA 94305. RP BALDI, P (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 5 TC 24 Z9 26 U1 0 U2 0 PU MIT PRESS PI CAMBRIDGE PA 55 HAYWARD ST JOURNALS DEPT, CAMBRIDGE, MA 02142 SN 0899-7667 J9 NEURAL COMPUT JI Neural Comput. PD MAY PY 1993 VL 5 IS 3 BP 402 EP 418 DI 10.1162/neco.1993.5.3.402 PG 17 WC Computer Science, Artificial Intelligence SC Computer Science GA KZ513 UT WOS:A1993KZ51300008 ER PT J AU MANDZHAVIDZE, N RAMATY, R AF MANDZHAVIDZE, N RAMATY, R TI PARTICLE-ACCELERATION IN SOLAR-FLARES SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT 13TH EUROPEAN COSMIC RAY SYMP CY JUL 27-31, 1992 CL CERN, GENEVA, SWITZERLAND SP INT UNION PURE & APPL PHYS, COSM RAY COMMISS, EUROPEAN PHYS SOC, LECROY, PHILIPS COMPONENTS, SWISS ACAD SCI, SWISS BANK, SWISS NATL SCI FDN, SWISSAIR HO CERN ID GAMMA-RAY LINE; ENERGY NEUTRAL RADIATION; CURRENT LOOP COALESCENCE; 1980 JUNE 21; RELATIVISTIC ELECTRONS; PROTON ACCELERATION; FERMI ACCELERATION; INTERPLANETARY SHOCKS; CORONAL LOOP; EVENTS AB We present an overview of the variety of observational data through which particle acceleration is manifested in solar flares. These data consist of direct energetic particle measurements, as well as radio, X-ray, gamma-ray and neutron observations, including new data from GAMMA-1, GRANAT and Compton GRO. We discuss the evidence showing the existence of impulsive and gradual solar particle events. We also discuss recent developments in acceleration theory and in the modelling of particle transport and interactions in solar flares. C1 GSFC,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. NR 149 TC 18 Z9 19 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY PY 1993 SU 33AB BP 141 EP 160 PG 20 WC Physics, Particles & Fields SC Physics GA LK356 UT WOS:A1993LK35600013 ER PT J AU BARNES, NP FILER, ED NARANJO, FL RODRIGUEZ, WJ KOKTA, MR AF BARNES, NP FILER, ED NARANJO, FL RODRIGUEZ, WJ KOKTA, MR TI SPECTROSCOPIC AND LASING PROPERTIES OF HOTMLUAG SO OPTICS LETTERS LA English DT Article ID HOLMIUM AB Ho:Tm:LuAG has been grown, examined spectroscopically, and lased at 2.1 mum. Ho:Tm:LuAG was selected for this experimental investigation when quantum-mechanical modeling predicted that it would be a good laser material for Ho laser operation on one of the I-5(7) to I-5(8) transitions. Lasing was achieved at 2.100 mum, one of the three wavelengths predicted to be most probable for laser action. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. SCI & TECHNOL CORP,HAMPTON,VA 23666. UNION CARBIDE CORP,WASHOUGAL,WA 98671. RP BARNES, NP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 6 TC 31 Z9 33 U1 1 U2 7 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 1 PY 1993 VL 18 IS 9 BP 708 EP 710 DI 10.1364/OL.18.000708 PG 3 WC Optics SC Optics GA KY942 UT WOS:A1993KY94200014 PM 19802247 ER PT J AU SPIRKOVSKA, L AF SPIRKOVSKA, L TI 3-DIMENSIONAL OBJECT RECOGNITION USING SIMILAR TRIANGLES AND DECISION TREES SO PATTERN RECOGNITION LA English DT Article DE OBJECT RECOGNITION; INVARIANT CLASSIFICATION; 2-DIMENSIONAL; 3-DIMENSIONAL; TRIANGLE FEATURE; DECISION TREES AB A system, TRIDEC, that is capable of distinguishing between a set of objects, despite changes in the objects' positions in the input field, their size, or their rotational orientation in three-dimensional (3D) space, is described. TRIDEC combines very simple yet effective features with the classification capabilities of inductive decision tree methods. The feature vector is a list of all similar triangles defined by connecting all combinations of three pixels in a coarse coded 127 x 127 pixel input field. The classification is accomplished by building a decision tree using the information provided from a limited number of translated, scaled, and rotated samples. Simulation results are presented which show that TRIDEC achieves 94% recognition accuracy in the two-dimensional (2D) invariant object recognition domain and 98% recognition accuracy in the 3D invariant object recognition domain after training on only a small sample of transformed views of the objects. RP SPIRKOVSKA, L (reprint author), NASA,AMES RES CTR,MAIL STOP 269-3,MOFFETT FIELD,CA 94035, USA. NR 5 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0031-3203 J9 PATTERN RECOGN JI Pattern Recognit. PD MAY PY 1993 VL 26 IS 5 BP 727 EP 732 DI 10.1016/0031-3203(93)90125-G PG 6 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA LK644 UT WOS:A1993LK64400007 ER PT J AU ZHOU, Y AF ZHOU, Y TI DEGREES OF LOCALITY OF ENERGY-TRANSFER IN THE INERTIAL RANGE SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Letter ID ISOTROPIC TURBULENCE AB Recent interpretations of direct numerical simulation (DNS) measurements have led some authors to suggest that energy is largely transferred downscale locally, supporting a basic concept of the Kolmogorov phenomenology that leads to the universal inertial subrange. However, these authors conclude that the local energy transfer results from nonlocal triad interactions. This claim brings into question the validity of the assumption of the statistical independence of the large- and small-scale motions in the Kolmogorov universal theory of turbulence. In this Letter, the measured raw transfer interactions have been summed in a way that directly indicates the scale disparity (s) of contributions to the net energy flux across the spectrum. It is found that the dependence upon s closely follows the s-4/3 form predicted by classical arguments. As a result, it is concluded that DNS measurements, in fact, lend support to the classical Kohnogorov phenomenology of local interactions and local transfer in an inertial range. C1 STANFORD UNIV,CTR TB RES,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 14 TC 75 Z9 76 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD MAY PY 1993 VL 5 IS 5 BP 1092 EP 1094 DI 10.1063/1.858593 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA KZ546 UT WOS:A1993KZ54600002 ER PT J AU LINGENFELTER, R CHAN, KW RAMATY, R AF LINGENFELTER, R CHAN, KW RAMATY, R TI DIFFUSE GALACTIC ANNIHILATION RADIATION AND THE PRESENT RATE OF GALACTIC NUCLEOSYNTHESIS SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID GAMMA-RAY SPECTRUM; I SUPER-NOVAE; CENTER REGION; CENTER DIRECTION; GRIS OBSERVATIONS; LINE EMISSION; AL-26; EXPLOSIONS; PULSARS; ORIGIN AB Observations of positron annihilation radiation from the inner region of the Galaxy show that there are two components of the radiation: a steady, diffuse galactic disk component and a variable component from discrete, presumably compact sources. Here we focus on the observations of the diffuse galactic emission and their implications for the present galactic rate of iron nucleosynthesis. We discuss recent calculations of the nucleosynthetic yield and the survival of positrons in supernova ejecta, expected from current supernova models. These calculations show that positrons from the beta+ decay of nucleosynthetic Co-56 --> Fe-56, Sc-44 --> Ca-44, and Al-26 --> Mg-26, can easily account for the observed galactic annihilation radiation, and they suggest a present galactic rate of Fe-16 nucleosynthesis of approximately (0.8 +/- 0.5) M.) per 100 yr. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RP UNIV CALIF SAN DIEGO, CTR ASTROPHYS & SPACE SCI 0111, LA JOLLA, CA 92093 USA. NR 69 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 EI 1873-6270 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD MAY PY 1993 VL 227 IS 1-5 BP 133 EP 142 DI 10.1016/0370-1573(93)90061-H PG 10 WC Physics, Multidisciplinary SC Physics GA LH206 UT WOS:A1993LH20600011 ER PT J AU STERN, DP AF STERN, DP TI ALL I REALLY NEED TO KNOW ... SO PHYSICS TODAY LA English DT Article RP STERN, DP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Wright, Dawn/A-4518-2011 OI Wright, Dawn/0000-0002-2997-7611 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1993 VL 46 IS 5 BP 63 EP 63 PG 1 WC Physics, Multidisciplinary SC Physics GA LC117 UT WOS:A1993LC11700016 ER PT J AU DAVIDSON, G AF DAVIDSON, G TI SOLAR-CYCLES EFFECT ON HOW HIGH HUBBLE FLIES SO PHYSICS TODAY LA English DT Letter RP DAVIDSON, G (reprint author), NASA,WASHINGTON,DC 20546, USA. 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 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1993 VL 46 IS 5 BP 91 EP & DI 10.1063/1.2808920 PG 0 WC Physics, Multidisciplinary SC Physics GA LC117 UT WOS:A1993LC11700019 ER PT J AU FEYNMAN, J AF FEYNMAN, J TI THE TRUTH ABOUT FEYNMAN FATHER SO PHYSICS TODAY LA English DT Letter RP FEYNMAN, J (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1993 VL 46 IS 5 BP 91 EP 91 DI 10.1063/1.2808919 PG 1 WC Physics, Multidisciplinary SC Physics GA LC117 UT WOS:A1993LC11700017 ER PT J AU GRANT, L DAUGHTRY, CST VANDERBILT, VC AF GRANT, L DAUGHTRY, CST VANDERBILT, VC TI POLARIZED AND SPECULAR REFLECTANCE VARIATION WITH LEAF SURFACE-FEATURES SO PHYSIOLOGIA PLANTARUM LA English DT Article DE CUTICLE; LEAF SURFACE; LIGHT; POLARIZATION; REFLECTANCE; SCATTERING; SPECULAR REFLECTANCE ID BIDIRECTIONAL SCATTERING; LEAVES; LIGHT; TRANSMITTANCE; DIFFUSE; CORN AB The linearly polarized reflectance from a leaf depends on the characteristics of the leaf surface. In the present study the leaf reflectance of a number of plant species with varying surface characteristics was measured at the Brewster angle with a polarization photometer having 5 visible and near-infrared wavelength bands. We found that all leaf surfaces polarized incident light. Differences among species could be explained by variation in surface features. The results support our hypothesis that the polarized light is reflected by the leaf surface, not by its interior. Two mechanisms appeared responsible for the linearly polarized reflectance: (1) specular reflectance and (2) surface particle scattering. In most cases, large values of linearly polarized reflectance could be attributed to specular reflectance from the leaf surface. Attribution required knowledge of the optical dimensions of features on the leaf surface. C1 USDA ARS,BELTSVILLE AGR RES CTR,REMOTE SENSING RES LAB,BARC W,BELTSVILLE,MD 20705. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 29 TC 38 Z9 41 U1 2 U2 16 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0031-9317 J9 PHYSIOL PLANTARUM JI Physiol. Plant. PD MAY PY 1993 VL 88 IS 1 BP 1 EP 9 DI 10.1111/j.1399-3054.1993.tb01753.x PG 9 WC Plant Sciences SC Plant Sciences GA LH314 UT WOS:A1993LH31400001 ER PT J AU PIASTUCH, WC OBENLAND, DM BROWN, CS AF PIASTUCH, WC OBENLAND, DM BROWN, CS TI ALTERED GRAVITY-INDUCED CHANGES IN GROWTH AND STARCH CONCENTRATIONS IN MAIZE SEEDLINGS SO PLANT PHYSIOLOGY LA English DT Meeting Abstract C1 BIONET CORP,KENNEDY SPACE CTR,FL 32899. NASA,MD RES,KENNEDY SPACE CTR,FL 32899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1993 VL 102 IS 1 SU S BP 87 EP 87 PG 1 WC Plant Sciences SC Plant Sciences GA LD890 UT WOS:A1993LD89000485 ER PT J AU OBENLAND, DM BROWN, S AF OBENLAND, DM BROWN, S TI CARBOHYDRATE-METABOLISM IN EXCISED WHEAT LEAVES EXPOSED TO CLINOROTATION SO PLANT PHYSIOLOGY LA English DT Meeting Abstract C1 NASA,MD RES,KENNEDY SPACE CTR,FL 32899. BIONET CORP,KENNEDY SPACE CTR,FL 32899. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1993 VL 102 IS 1 SU S BP 88 EP 88 PG 1 WC Plant Sciences SC Plant Sciences GA LD890 UT WOS:A1993LD89000486 ER PT J AU MARAN, SP KINNEY, AL AF MARAN, SP KINNEY, AL TI RECENT RESULTS FROM THE HUBBLE-SPACE-TELESCOPE SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID GALACTIC FOUNTAIN; ALPHA EMISSION; PROTON-BEAMS; GALAXY; ULTRAVIOLET; ABSORPTION; EVOLUTION; NUCLEI; VELA AB A selection of recent findings from the Hubble Space Telescope (HST) is presented as a supplement to the earlier review by Kinney and Maran (1991). In stellar astrophysics, noteworthy results include the first ultraviolet science from the High Speed Photometer, as well as spectroscopic studies of black hole and neutron star binaries and a flare star. The interstellar medium in the Galaxy and in an intervening galaxy along the line of sight to a quasar have been sampled, and new information gained on intergalactic absorption clouds along the same, and other, lines of sight. Imaging observations of planetary nebulae in the Magellanic Clouds are eye openers; prior findings from speckle interferometry are seen to be sometimes unreliable. A ''movie'' composed of images depicting the evolution of a rare great storm on Saturn should stand as the best obtainable for decades to come. A distant weak radio galaxy appears to be a newly formed elliptical galaxy, in which star formation was essentially coincident with the initial collapse that produced the galaxy. And, the percentage of spiral galaxies in a cluster seen as it was several billion years ago appears to be much higher than in comparably rich clusters at recent epochs, providing new evidence for evolution in galaxy systems. Ultraviolet spectropolarimetry helps to identify the physics at work at the center of a blazar, and snapshots taken in gyroscopic pointing mode reveal that closely spaced gravitationally lensed images are hard to find. This is a modest sample of the tremendous outpouring of new research results from the HST over the past year or so. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP MARAN, SP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 680,GREENBELT,MD 20771, USA. NR 92 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 1993 VL 105 IS 687 BP 447 EP 463 DI 10.1086/133178 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA LD340 UT WOS:A1993LD34000001 ER PT J AU VANE, G GOETZ, AFH AF VANE, G GOETZ, AFH TI TERRESTRIAL IMAGING SPECTROMETRY - CURRENT STATUS, FUTURE-TRENDS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID WATER-VAPOR; CANOPY; MODEL; REFLECTANCE; NEVADA AB A review Of recent progress in thefield of imaging spectrometry is presented based on the 14 articles comprising the special issue of this journal. The results presented were achieved through research done with data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), the first imaging spectronwter to cover the full solar reflected portion of the spectrum. The majority of the early work in imaging spectrometry prior to AVIRIS focused largely on geological applications and specifically surface mineral identification. In the past 5 years, the range of applications has expanded into the scientific disciplines of ecology, hydrology, oceanography, and atmospheric science. Significant progress has also been made in sensor design and calibration, and information extraction. NASA plans to place high spectral resolution sensors in earth orbit within the next few years; two have been flown already on recent planetary missions and have proven to be of great value to the study of planetary surfaces and atmospheres. The work presented in this issue will lead directly to more effective utilization of imaging spectrometry in the study of the earth. We present a discussion of future trends in imaging spectrometry at the conclusion of this article. C1 UNIV COLORADO,CIRES,CTR STUDY EARTH SPACE,BOULDER,CO 80309. UNIV COLORADO,DEPT GEOL SCI,BOULDER,CO 80309. RP VANE, G (reprint author), JET PROP LAB,OFF SPACE SCI & INSTRUMENTS,MS 180703,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 43 TC 85 Z9 106 U1 1 U2 19 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY-JUN PY 1993 VL 44 IS 2-3 BP 117 EP 126 DI 10.1016/0034-4257(93)90011-L PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LB118 UT WOS:A1993LB11800001 ER PT J AU VANE, G GREEN, RO CHRIEN, TG ENMARK, HT HANSEN, EG PORTER, WM AF VANE, G GREEN, RO CHRIEN, TG ENMARK, HT HANSEN, EG PORTER, WM TI THE AIRBORNE VISIBLE INFRARED IMAGING SPECTROMETER (AVIRIS) SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is a facility consisting of a flight system, a ground data system, a calibrationfacility, and a full-time operations team. The facility was developed by the Jet Propulsion Laboratory (JPL) underfundingfrom the National Aeronautics and Space Administration (NASA). NASA also provides fundingfor operations and maintenance. Theflight system is a whisk-broom imager that acquires data in 224 narrow, contiguous spectral bands covering the solar reflected portion of the electromagnetic spectrum. It is flown aboard the NASA high altitude ER-2 research aircraft. The ground data system is a facility dedicated to the processing and distribution of data acquired by AVIRIS. It operates year round at JPL. The calibration facility consists of a calibration laboratory at JPL and a suite of field instruments and procedures for performing inflight calibration of AVIRIS. A small team of engineers, technicians and scientists supports a yearly operations schedule that includes 6 months of flight operations, 6 months of routine ground maintenance of the flight system, and year-round data processing and distribution. Details of the AVIRIS system, its performance history, and future plans are described. RP VANE, G (reprint author), JET PROP LAB,MS 180703,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 38 TC 398 Z9 412 U1 2 U2 23 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY-JUN PY 1993 VL 44 IS 2-3 BP 127 EP 143 DI 10.1016/0034-4257(93)90012-M PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LB118 UT WOS:A1993LB11800002 ER PT J AU CARRERE, V CONEL, JE AF CARRERE, V CONEL, JE TI RECOVERY OF ATMOSPHERIC WATER-VAPOR TOTAL COLUMN ABUNDANCE FROM IMAGING SPECTROMETER DATA AROUND 940 NM - SENSITIVITY ANALYSIS AND APPLICATION TO AIRBORNE VISIBLE INFRARED IMAGING SPECTROMETER (AVIRIS) DATA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB Two simple techniques to retrieve path precipitable water from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) (Vane et al., 1993) high spectral resolution radiance data (Continuum interpolated Band Ratio, CIBR, and Narrow/Wide ratio, NIW), using the 940 nm water absorption band, are compared. Since the shape and depth of the atmospheric water bands are influenced not only by the water present but also by surface (background) reflectance, atmospheric scattering, and instrument radiance by calibration, a sensitivity analysis was performed using the radiative transfer code LOWTRAN 7 (Kneizys et al., 1988) to determine which one of these two approaches will provide a better estimate over land and water areas. The CIBR proved to be the technique less sensitive to perturbing effects, except for errors in visibility estimate. Both techniques were applied to AVIRIS radiance data acquired over Salton Sea, California. Resulting images confirmed that the use of a constant gray reflectance in the model led to a higher overestimation of the amount of water retrieved for N/W over vegetated areas. Validation was performed through comparison between an independent estimate Of water vaporfrom concurrent Reagan sunphotometer measurements and AVIRIS estimates. Amounts retrieved using the N/W approach match more closely in situ measurements, even after adjusting model parameters for background reflectance, viewing geometry and type Of aerosol at the site. The 13% underestimation observed for the CIBR was explained by small differences AL(lambda(i)) between AVIRIS and LOWTRAN 7 modeled radiances. Resultsfrom this study emphasizes the importance Of accurate instrument calibration in flight and correct physical modeling of atmospheric absorptions. C1 JET PROP LAB,PASADENA,CA 91109. NR 21 TC 57 Z9 61 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY-JUN PY 1993 VL 44 IS 2-3 BP 179 EP 204 DI 10.1016/0034-4257(93)90015-P PG 26 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LB118 UT WOS:A1993LB11800005 ER PT J AU CARDER, KL REINERSMAN, P CHEN, RF MULLERKARGER, F DAVIS, CO HAMILTON, M AF CARDER, KL REINERSMAN, P CHEN, RF MULLERKARGER, F DAVIS, CO HAMILTON, M TI AVIRIS CALIBRATION AND APPLICATION IN COASTAL OCEANIC ENVIRONMENTS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID OPTICAL-PROPERTIES; REFLECTANCE MODEL; CHLOROPHYLL-A; ABSORPTION; WATERS AB The Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) is a test-bed for future spacecraft sensors such as the High-Resolution Imaging Spectrometer and the Moderate-Resolution Imaging Spectrometers planned for the Earth Observing System. To use this sensor for ocean applications, S/N was increased by spatial averaging of images. Post-flight recalibration was accomplished by measuring in situ the water-leaving radiance at flight time, modeling its transmission to the aircraft, and adding modeled atmospheric radiance to that value. The preflight calibration curve was then adjusted until aircraft and modeled total radiance values matched. Water-leaving radiance values from the recalibrated AVIRIS imagery were consistent with in situ data supporting the validity of the approach. Imagery of the absorption coefficient at 415 nm and backscattering coefficient at 671 nm were used to depict the dissolved and particulate constituents of the Tampa Bay plume during late, ebb-tidal conditions. C1 JET PROP LAB,PASADENA,CA 91109. RP CARDER, KL (reprint author), UNIV S FLORIDA,DEPT MARINE SCI,140 7TH AVE S,ST PETERSBURG,FL 33701, USA. NR 22 TC 57 Z9 58 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY-JUN PY 1993 VL 44 IS 2-3 BP 205 EP 216 DI 10.1016/0034-4257(93)90016-Q PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LB118 UT WOS:A1993LB11800006 ER PT J AU HAMILTON, MK DAVIS, CO RHEA, WJ PILORZ, SH CARDER, KL AF HAMILTON, MK DAVIS, CO RHEA, WJ PILORZ, SH CARDER, KL TI ESTIMATING CHLOROPHYLL CONTENT AND BATHYMETRY OF LAKE TAHOE USING AVIRIS DATA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SPECTRAL ABSORPTION; REFLECTANCE MODEL; WATERS; PHYTOPLANKTON; OCEAN; SYSTEM; INLAND; COLOR AB An AVIRIS image was obtained at Lake Tahoe on 9 August 1990, along with in situ data. Profiles of percent transmission of monochromatic light, stimulated chlorophyll fluorescence, photosynthetically available radiation, and spectral upwelling and downwelling irradiance, and upwelling radiance were measured. Chlorophyll-a + phaeopigments, total particulate absorption, detritus absorption, and absorption due to colored dissolved organic matter were measured on discrete samples. Spectral reflectance at the surface was measured with a handheld spectroradiometer. Image preprocessing included increasing the instrument signal-to-noise ratio by filtering to reduce patterned noise and spatial resampling, and application Of LOWTRAN-7 as an atmospheric correction. Several analyses were then performed illustrating the utility of the AVIRIS over a dark water scene. The water-leaving radiance measured by the AVIRIS compares very well with the upwelling radiance measured in-water, everywhere but in the very short wavelength channels. After recalibrating one AVIRIS channel, the chlorophyll concentration derived from the image compares extremely well with that measured with bottle samples. Application Of the pigment algorithm to the rest of the lake was confounded by covarying absorption at 440 nm by colored dissolved organic matter (CDOM), underscoring the importance Of accurate calibration Of the instrument in the short-wavelength channels. Surface spectroradiometer measurements made along a transect Of varying depth were used to condition a multiple linear regression bathymetry model. By applying the model coefficients to a portion of the image, a bathymetry map of the shallow parts of the lake was constructed which compares favorably with published lake soundings, indicating the potential for a bottom-reflectance correction to coastal ocean color imagery. C1 UNIV S FLORIDA,DEPT MARINE SCI,ST PETERSBURG,FL 33701. RP HAMILTON, MK (reprint author), JET PROP LAB,MS 300-323,4800 OAK DR,PASADENA,CA 91109, USA. NR 32 TC 49 Z9 56 U1 4 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY-JUN PY 1993 VL 44 IS 2-3 BP 217 EP 230 DI 10.1016/0034-4257(93)90017-R PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA LB118 UT WOS:A1993LB11800007 ER PT J AU BOUMSELLEK, S CHUTJIAN, A AF BOUMSELLEK, S CHUTJIAN, A TI PULSED, GRIDDED ELECTRON REVERSAL IONIZER SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ATTACHMENT RATE CONSTANTS; SQUARE-WAVE GENERATOR; HIGH-VOLTAGE; CFCL3; CCL4; AIR AB The design and performance of a new-type source of negative ions is presented. This device retains the idea of the so-called reversal electron attachment detector [READ, M. T. Bernius and A. Chutjian, J. Appl. Phys. 66, 2783 (1989)] to produce low-energy electrons by reversing electron trajectories at an electrode. Electrons are produced in the present device by several ribbon filaments that surround a cylindrical wire grid. They are accelerated through the grid, then decelerated to zero, or near-zero velocity at the surface of a tube. The tube (anode) is perforated with small holes through which effuse the target molecules. Electrons attach to form either parent and/or fragment negative ions. Attachment takes place at a location above the anode corresponding to a match between the electron energy and the attachment resonance energy. Negative ions are pulsed out of the attachment region and focused onto the entrance plane of a quadrupole mass selector. Electron and ion trajectory calculations are presented, and the performance illustrated with six molecules having attachment resonances in the range 0.0-2.2 eV. The detection sensitivity as measured using the method of standard additions is below 1 part-per-trillion, with a calculated conversion rate (ions/electrons) of 1.3%. Signal nonlinearity is discussed in terms of ion space-charge effects. The device also produces positive ions, and an analogous treatment may be carried through to characterize its performance in this mode. RP BOUMSELLEK, S (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 21 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1993 VL 64 IS 5 BP 1135 EP 1139 DI 10.1063/1.1144106 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA LB849 UT WOS:A1993LB84900003 ER PT J AU FORNEY, LJ MEEKS, EL MA, J FRALICK, GC AF FORNEY, LJ MEEKS, EL MA, J FRALICK, GC TI MEASUREMENT OF FREQUENCY-RESPONSE IN SHORT THERMOCOUPLE WIRES SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Experimental measurements are made for the steady-state frequency response of a supported thermocouple wire. In particular, the effects of axial heat conduction are demonstrated for both a supported one material wire (type K) and a two material wire (type T) with unequal material properties across the junction. The data for the amplitude ratio and phase angle are correlated to within 10% with the theoretical predictions of Fralick and Forney (1992) for a laser-heated junction with no bead. This is accomplished by choosing a natural frequency omega(n) for the wire data to correlate the first-order response at large gas temperature frequencies. Moreover, it is found that a large bead size (roughly twice the wire diameter) will increase the amplitude ratio at low frequencies and distort the phase angle. In the latter case, it is necessary to increase the thermocouple wire length by 20% in the theory to correlate the data when the junctions have beads (silver soldered). C1 GEORGIA INST TECHNOL,MICROELECTR RES CTR,ATLANTA,GA 30332. GEORGIA INST TECHNOL,SCH MECH ENGN,ATLANTA,GA 30332. NASA,LEWIS RES CTR,RES SENSOR TECHNOL BRANCH,CLEVELAND,OH 44135. RP FORNEY, LJ (reprint author), GEORGIA INST TECHNOL,SCH CHEM ENGN,ATLANTA,GA 30332, USA. NR 9 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 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1993 VL 64 IS 5 BP 1280 EP 1286 DI 10.1063/1.1144080 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA LB849 UT WOS:A1993LB84900031 ER PT J AU TRALLI, DM AF TRALLI, DM TI A SENSE OF WHERE YOU ARE - WILL THE PENTAGON SHARE ITS NAVIGATIONAL SATELLITES WITH THE REST OF US SO SCIENCES-NEW YORK LA English DT Editorial Material RP TRALLI, DM (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0036-861X J9 SCIENCES JI Sci.-New York PD MAY-JUN PY 1993 VL 33 IS 3 BP 14 EP 19 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA MQ048 UT WOS:A1993MQ04800009 ER PT J AU HOPSON, GD GRANT, RL AF HOPSON, GD GRANT, RL TI PRESSURIZED MODULES FOR SPACE STATION FREEDOM SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB Space Station Freedom (SSF) on-orbit working and living space is planned to provide maximum efficiency and utilization of the available space; flexibility for reconfiguration; and to establish a safe, productive, and comfortable working environment. The U.S. Laboratory (USL) payload accommodations and maintenance work areas are planned to support a mixture of life sciences and materials processing experiments. The USL has special utilities installed to provide unique laboratory services such as the nitrogen and water distribution and waste gas removal, additional power capability and dedicated customer data systems and thermal control loop. Crew workstations, storage, and facilities in the Habitation module, and station housekeeping and supporting subsystems (power, thermal, life support, etc.) are discussed. Pressurized logistics modules (PLM) and unpressurized logistics carriers (ULC) are provided for SSF cargo resupply/return. The USL and Habitation modules and resource nodes are built to a common structural design. The primary cylindrical structure is made up of aluminum ring frames with waffle grid skins to complete the pressure shell. Each end consists of a conical bulkhead, hatch, and berthing mechanism. Multilayer thermal insulation and an aluminum meteoroid/debris shield is provided for external protection. The nodes have four radial ports for interconnection of the module pattern. The PLM also has maximum commonality with the other pressurized modules. This includes common ring frames and waffle grid skin; multilayer insulation and debris shield; and one common endcone, with the bulkhead, hatch, and berthing mechanism. The nonberthing end has a large hatch (approx. 2.57 m x 2.57 m) to facilitate resupply ground processing. The current ULC design concept is built around the same ring frame as the PLM, without the pressure shell. The ULC will be configured to carry a variety of subcarriers that include fluids subcarriers for laboratory fluids and Environmental Control and Life Support System nitrogen, high-pressure gas subcarriers for backup nitrogen and oxygen, and dry cargo subcarriers for unpressurized payloads and orbital replaceable units. Diagrams and pictures that show the configurations, internal arrangement and architecture of the USL and Habitation modules and resource node structures are provided. RP HOPSON, GD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD MAY PY 1993 VL 13 IS 3 BP 231 EP 243 PG 13 WC Engineering, Aerospace SC Engineering GA LJ451 UT WOS:A1993LJ45100002 ER PT J AU GRINER, CS NONEMAN, SR AF GRINER, CS NONEMAN, SR TI SPACE STATION FREEDOM PAYLOAD OPERATIONS IN THE 21ST-CENTURY SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB The operational concept for Space Station Freedom (SSF) was initially developed by the Space Station Operations Task Force in 1986. The concept and its implementation planning has been subsequently embedded into the international program documentation from the Memorandum of Understanding to the detailed planning of all the Partners, the key aspects of which have been discussed in the forum of the IAF Congress. With the restructure activity in later 1990 and early 1991, the Marshall Space Flight Center, responsible for the integration of payload operations across the user community, responded to the imperative for lower-cost, more effective operations while maintaining the conceptual framework. The objective of this paper is to discuss the modified approach to the accommodation of payload operations in light of both flight and ground systems changes. The challenges for the man-tended capability payload operations as well as those for the permanently manned capability (PMC) will be assessed. PMC is the anchor point for the payload operations in the 21st century for the SSF and will, therefore, define the prospective for accomplishment of the prime objective for space station science and exploration for the international user community. RP GRINER, CS (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD MAY PY 1993 VL 13 IS 3 BP 255 EP 261 PG 7 WC Engineering, Aerospace SC Engineering GA LJ451 UT WOS:A1993LJ45100004 ER PT J AU FREEMAN, DC WILHITE, AW TALAY, TA AF FREEMAN, DC WILHITE, AW TALAY, TA TI ADVANCED MANNED LAUNCH SYSTEM STUDY STATUS SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 42ND CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-11, 1991 CL MONTREAL, CANADA SP INT ASTRONAUT FEDERAT AB Various concepts for advanced manned launch systems (AMLS) are examined for delivery missions to space station and polar orbit. Included are single- and two-stage winged systems with rocket and/or airbreathing propulsion systems. For near-term technologies, two-stage, reusable rocket systems are favored over single-stage rocket or airbreathing/rocket systems. Advanced technologies enable viable single-stage-to-orbit (SSTO) concepts. Although two-stage rocket systems continue to be lighter in dry weight than SSTOs, advantages in simpler operations may make SSTOs more cost effective over the life cycle. Generally, rocket systems maintain a dry weight advantage over airbreathing systems at advanced technology levels, but to a lesser degree than when near-term technologies are used. More detailed understanding of vehicle systems and associated ground and flight operations requirements and procedures is essential in determining quantitative discrimination between these latter concepts. RP FREEMAN, DC (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD MAY PY 1993 VL 13 IS 3 BP 349 EP 362 PG 14 WC Engineering, Aerospace SC Engineering GA LJ451 UT WOS:A1993LJ45100013 ER PT J AU HAIGHT, WR PARRISH, JD HAYES, TA AF HAIGHT, WR PARRISH, JD HAYES, TA TI FEEDING ECOLOGY OF DEEP-WATER LUTJANID SNAPPERS AT PENGUIN BANK, HAWAII SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID DEEP-SEA; COMMUNITIES; FISHERIES; FISH AB Deepwater snappers are a valuable component of fisheries on slopes and banks in Hawaii and in much of the world's tropics. Their ecology and trophic relationships in these deepwater habitats are poorly known. Line fishing in this study simultaneously collected six of the seven lutjanid species that commonly occur in the major deepwater snapper fishery at Penguin Bank, Hawaii. The catch rate of each species showed diel variability; the patterns of some species were distinctly different. The depth distribution of feeding, as indicated by depth of capture, differed considerably among species; all species were taken within several meters of the bottom. Size (fork length) of the predator species did not appear to be stratified by time of capture (daylight versus darkness) or median capture depth. Regurgitation of gut contents seemed to be reduced when fish were retrieved at a rate that was slower than used in commercial practice but rapid enough to prevent death or morbidity while hooked. The food remaining in line-caught specimens appeared to be representative of what was originally eaten. The six snapper species ate considerable amounts of a wide range of pelagic animals and demersal fishes and much smaller quantities of a few invertebrate benthic groups. Etelis coruscans, Etelis carbunculus, and Aprion virescens formed a distinct, primarily piscivorous feeding guild. Pristipomoides filamentosus and Pristipomoides sieboldii formed a distinct guild dominated by zooplankton feeding. The few specimens of Pristipomoides zonatus appeared somewhat intermediate in diet. Important planktonic prey groups included crustaceans, pteropods, and large, pelagic, colonial urochordates (e.g., salps). Urochordates made a significant contribution to the diet even for some of the primarily piscivorous species. Major diel and seasonal shifts in diet were found only in P. filamentosus; they involved the relative proportions of fish, and especially of the major planktonic groups. Our information on diet composition and depth and time of feeding (catch) suggests that considerable resource partitioning occurs among these deepwater snappers. C1 UNIV HAWAII,US FISH & WILDLIFE SERV,HAWAII COOPERAT FISHERY RES UNIT,HONOLULU,HI 96822. RP HAIGHT, WR (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 61 TC 35 Z9 36 U1 1 U2 8 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1993 VL 122 IS 3 BP 328 EP 347 DI 10.1577/1548-8659(1993)122<0328:FEODLS>2.3.CO;2 PG 20 WC Fisheries SC Fisheries GA LR876 UT WOS:A1993LR87600003 ER PT J AU WOLF, WW VAUGHN, CR HARRIS, R LOPER, GM AF WOLF, WW VAUGHN, CR HARRIS, R LOPER, GM TI INSECT RADAR CROSS-SECTIONS FOR AERIAL DENSITY-MEASUREMENTS AND TARGET CLASSIFICATION SO TRANSACTIONS OF THE ASAE LA English DT Article DE POLARIZATION; ASPECTS ANGLE; CORN EARWORM; HONEY BEE; STINK BUG; BOLLWEEVIL; LESSER CORN STALK BORER; FALL ARMYWORM ID MIGRATION AB Radar cross-sections (RCS) of adults Of six insect species were measured with a high-resolution radar for selected aspect angles and polarization angles. These data were fit to transcendental equations relating RCS to aspect angle or polarization angle. Insect weight ranged from 256 mg to 10 mg for Helicoverpa zea (Boddie) and Anthonomus grandis grandis Boheman, respectively. Radar cross-sections varied from 3 cm2 to 5 x 10(-4) cm2 for an Apis mellifera (L.) queen and Elasmopalpus lignosellus, respectively. An example illustrates how mean RCS and polarization modulation can be used to develop an insect classification system. The results suggest that appropriately measured RCS properties can be used with altitude, time of flight, wing beating rate, flight direction, and true airspeed to define a classification system. Classification of radar targets could provide an estimate of the proportion of targets that have properties similar to a specific species. C1 NASA,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA. USDA ARS,HONEYBEE LAB,TUCSON,AZ. METRATEK INC,FALLS CHURCH,VA. RP WOLF, WW (reprint author), USDA ARS,CIPMRU,COLL STN,TX 77840, USA. NR 17 TC 13 Z9 15 U1 1 U2 2 PU AMER SOC AGRICULTURAL ENGINEERS PI ST JOSEPH PA 2950 NILES RD, ST JOSEPH, MI 49085-9659 SN 0001-2351 J9 T ASAE JI Trans. ASAE PD MAY-JUN PY 1993 VL 36 IS 3 BP 949 EP 954 PG 6 WC Agricultural Engineering SC Agriculture GA LP251 UT WOS:A1993LP25100044 ER PT J AU HEIN, TA THIEL, W LEE, TJ AF HEIN, TA THIEL, W LEE, TJ TI ABINITIO STUDY OF THE STABILITY AND VIBRATIONAL-SPECTRA OF PLUMBANE, METHYLPLUMBANE, AND HOMOLOGOUS COMPOUNDS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID HARMONIC FORCE-FIELDS; EFFECTIVE CORE POTENTIALS; MAIN-GROUP ELEMENTS; N = 0-3; ELECTRON CORRELATION; SINGLET METHYLENE; MICROWAVE-SPECTRA; MATRIX-ISOLATION; MOLECULES; DERIVATIVES AB Ab initio calculations on the title compounds are reported at the level of self-consistent-field theory, Moller-Plesset perturbation theory, and coupled-cluster theory (SCF, MP2, and CCSD(T), respectively). The thermodynamic stability of MH4 and H3MCH3 as well as the kinetic stability of MH4 with respect to loss of H-2 are found to decrease with increasing atomic number of M = Si-Pb. However, PbH4 and H3PbCH3 should be long-lived enough to be observable in the gas phase. The infrared spectra of these compounds are predicted. Trends in the calculated properties are discussed for M = Si-Pb. C1 UNIV GESAMTHSCH WUPPERTAL,W-5600 WUPPERTAL 1,GERMANY. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Lee, Timothy/K-2838-2012; Thiel, Walter/A-5677-2016 OI Thiel, Walter/0000-0001-6780-0350 NR 56 TC 15 Z9 15 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 29 PY 1993 VL 97 IS 17 BP 4381 EP 4385 DI 10.1021/j100119a021 PG 5 WC Chemistry, Physical SC Chemistry GA LA023 UT WOS:A1993LA02300021 ER PT J AU SULLIVAN, T TRIFFET, T AF SULLIVAN, T TRIFFET, T TI CHEMICAL-INDUSTRY AND THE SPACE PROGRAM SO CHEMICAL & ENGINEERING NEWS LA English DT Article C1 UNIV ARIZONA,NASA SPACE ENGN RES CTR,TUCSON,AZ 85721. NATL AERONAUT & SPACE ADM,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2347 J9 CHEM ENG NEWS JI Chem. Eng. News PD APR 26 PY 1993 VL 71 IS 17 BP 9 EP 11 PG 3 WC Chemistry, Multidisciplinary; Engineering, Chemical SC Chemistry; Engineering GA KY916 UT WOS:A1993KY91600010 ER PT J AU ADAMS, FC FATUZZO, M FREESE, K TARLE, G WATKINS, R TURNER, MS AF ADAMS, FC FATUZZO, M FREESE, K TARLE, G WATKINS, R TURNER, MS TI EXTENSION OF THE PARKER BOUND ON THE FLUX OF MAGNETIC MONOPOLES SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEON DECAY; NEUTRON STARS; SUPERCONDUCTIVE DETECTOR; ASTROPHYSICAL BODIES; FIELDS; GENERATION; LIMIT; CATALYSIS; SURVIVAL AB An extension of the Parker bound on the flux F of magnetic monopoles leads to a stronger bound than obtained previously. The survival and growth of a small galactic seed field requires F less-than-or-equal-to 10(-16)(m/10(17) GeV) cm-2 s-1 sr-1. This new limit rules out the possibility that monopoles much lighter than 10(17) GeV/c2 can provide the closure density of the Universe. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP ADAMS, FC (reprint author), UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109, USA. NR 41 TC 39 Z9 39 U1 0 U2 2 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 APR 26 PY 1993 VL 70 IS 17 BP 2511 EP 2514 DI 10.1103/PhysRevLett.70.2511 PG 4 WC Physics, Multidisciplinary SC Physics GA KY503 UT WOS:A1993KY50300002 ER PT J AU HARTLE, RE GREBOWSKY, JM AF HARTLE, RE GREBOWSKY, JM TI LIGHT-ION FLOW IN THE NIGHTSIDE IONOSPHERE OF VENUS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MODEL; ORBITER; THERMOSPHERE AB The flow characteristics of the light ions H+ and He+ have been studied in the midnight region of the ionosphere of Venus. Measurements of ion composition, electron and ion temperatures and magnetic fields by instruments onboard the Pioneer Venus Orbiter have been used in the electron and ion equations of conservation of mass and momentum to derive the vertical flow velocities of H+ and He+. When average height profiles of the measured quantities were used, H+ was found to flow upward, accelerating to speeds of almost 1 km s-1 at the ion-exobase. In a similar fashion, He+ was found to flow downward into the neutral atmosphere where it is readily quenched by charge transfer reactions. The polarization electric field played an important role in forcing H+ upward, but did not contribute enough to the He+ force balance to produce upward flow. At the ion-exobase, the outward electric polarization force on H+ was shown to be five times the gravitational force. Using an analogy with the terrestrial ion-exosphere, H+ was inferred to flow upward into the ionotail of Venus and accelerate to escape speeds. A planet averaged escape flux of 1.4 x 10(7) cm-2 s-1 was calculated, which is comparable to hydrogen loss rates estimated by other investigators. RP HARTLE, RE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 914,GREENBELT,MD 20771, USA. RI Grebowsky, Joseph/I-7185-2013 NR 29 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1993 VL 98 IS E4 BP 7437 EP 7445 DI 10.1029/93JE00399 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LA444 UT WOS:A1993LA44400005 ER PT J AU KANIK, I TRAJMAR, S NICKEL, JC AF KANIK, I TRAJMAR, S NICKEL, JC TI TOTAL ELECTRON-SCATTERING AND ELECTRONIC STATE EXCITATIONS CROSS-SECTIONS FOR O-2, CO, AND CH4 SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ENERGY-RANGE; IMPACT EXCITATION; ANGULAR-DISTRIBUTION; ELASTIC-SCATTERING; METHANE; IONIZATION; O2; MOLECULES; REGION; ETHANE AB Available electron collision cross section data concerning total and elastic scattering, vibrational excitation, and ionization for O2, CO, and CH4 have been critically reviewed, and a set of cross sections for modeling of planetary atmospheric behavior is recommended. Utilizing these recommended cross sections, we derived total electronic state excitation cross sections and upper limits for dissociation cross sections, which in the case of CH4 should very closely equal the actual dissociation cross section. C1 UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92521. RP KANIK, I (reprint author), JET PROP LAB,MS 183-601,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 48 TC 58 Z9 59 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1993 VL 98 IS E4 BP 7447 EP 7460 DI 10.1029/92JE02811 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA LA444 UT WOS:A1993LA44400006 ER PT J AU MARTIN, JML TAYLOR, PR LEE, TJ AF MARTIN, JML TAYLOR, PR LEE, TJ TI ACCURATE ABINITIO QUARTIC FORCE-FIELDS FOR THE N2O AND CO2 MOLECULES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NITROUS-OXIDE; BASIS SETS; SINGLES; ATOMS AB The quartic force fields of N2O and CO2 have been computed ab initio using large basis sets of spdf and spdfg quality and augmented coupled-cluster (CCSD(T)) methods. The CCSD(T)/spdf frequencies for N2O, and the CCSD(T)/spdfg ones for CO2, are in excellent agreement with experiment. g functions appear to be important for cumulenic double bond stretches and bends. Improving the basis from spdf to spdfg appears to shorten double bonds by almost-equal-to 0.003 angstrom; the effect on single bonds is smaller and too unsystematic to be quantified. SCF level anharmonicities for N2O are qualitatively incorrect: this is not the case for CO2 where reasonable agreement with experiment is reached even at this level. Of the various published experimental force fields for N2O and CO2, the ones obtained by algebraic contact transformation appear to be the most reliable. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. LIMBURGS UNIV CENTRUM,DEPT SBM,B-3590 DIEPENBEEK,BELGIUM. UNIV INSTELLING ANTWERP,DEPT CHEM,B-2610 WILRIJK,BELGIUM. RP MARTIN, JML (reprint author), SAN DIEGO SUPERCOMP CTR,POB 85608,SAN DIEGO,CA 92186, USA. RI Lee, Timothy/K-2838-2012; Martin, Jan/A-7457-2008 OI Martin, Jan/0000-0002-0005-5074 NR 32 TC 79 Z9 79 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 23 PY 1993 VL 205 IS 6 BP 535 EP 542 DI 10.1016/0009-2614(93)80009-E PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA KY292 UT WOS:A1993KY29200009 ER PT J AU RUSSELL, JM TUCK, AF GORDLEY, LL PARK, JH DRAYSON, SR HARRIES, JE CICERONE, RJ CRUTZEN, PJ AF RUSSELL, JM TUCK, AF GORDLEY, LL PARK, JH DRAYSON, SR HARRIES, JE CICERONE, RJ CRUTZEN, PJ TI HALOE ANTARCTIC OBSERVATIONS IN THE SPRING OF 1991 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE HOLE AB HALOE observations of O3, CH4, HF, H2O, NO, NO2, and HCl collected during the October 1991 Antarctic spring period are reported. The data show a constant CH4 mixing ratio of about 0.25 ppmv for the altitude range from 65 km down to about 25 km at the position of minimum wind speed in the vortex: i.e., the vortex center. and depressions in pressure versus longitude contours of NO, NO2, HF, and HCl in this same region. Water vapor, HF, and HCl enhancement are also observed in the vortex center region above approximately 25 km. Between 10 and 20 km, the expected mixing ratio signatures exist within the vortex, i.e., low ozone and dehydration. The water vapor increased by 50%, and the ozone level doubled in the vortex between October 11 and 24 in the 15 to 20 km layer. These changes imply a time constant for recovery from ozone hole conditions of 19 and 30 days for O3 and H2O, respectively. The data further show the presence of air inside the vortex between 3 and 30 mb which has mixing ratios characteristic of mid latitudes. C1 UNIV CALIF IRVINE,DEPT GEOSCI,IRVINE,CA 92717. MAX PLANCK INST CHEM,W-6500 MAINZ,GERMANY. G&A TECH SOFTWARE,HAMPTON,VA 23665. SERC,RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. NOAA,AERON LAB,BOULDER,CO 80303. UNIV MICHIGAN,ANN ARBOR,MI 48105. RP RUSSELL, JM (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 401B,HAMPTON,VA 23681, USA. RI Tuck, Adrian/F-6024-2011; Crutzen, Paul/F-6044-2012 OI Tuck, Adrian/0000-0002-2074-0538; NR 11 TC 74 Z9 74 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 23 PY 1993 VL 20 IS 8 BP 719 EP 722 DI 10.1029/93GL00497 PG 4 WC Geosciences, Multidisciplinary SC Geology GA LA342 UT WOS:A1993LA34200021 ER PT J AU FARRELL, WM DESCH, MD AF FARRELL, WM DESCH, MD TI CLOUD-TO-STRATOSPHERE LIGHTNING DISCHARGES - A RADIO-EMISSION MODEL - REPLY SO GEOPHYSICAL RESEARCH LETTERS LA English DT Note RP FARRELL, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 23 PY 1993 VL 20 IS 8 BP 763 EP 764 DI 10.1029/93GL00080 PG 2 WC Geosciences, Multidisciplinary SC Geology GA LA342 UT WOS:A1993LA34200033 ER PT J AU RUMMEL, JD AF RUMMEL, JD TI EXTRATERRESTRIAL INTELLIGENCE SO SCIENCE LA English DT Letter RP RUMMEL, JD (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 23 PY 1993 VL 260 IS 5107 BP 475 EP 475 DI 10.1126/science.260.5107.475 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA KY504 UT WOS:A1993KY50400005 PM 17830412 ER PT J AU HAPKE, BW NELSON, RM SMYTHE, WD AF HAPKE, BW NELSON, RM SMYTHE, WD TI THE OPPOSITION EFFECT OF THE MOON - THE CONTRIBUTION OF COHERENT BACKSCATTER SO SCIENCE LA English DT Article ID RETROREFLECTANCE; SATELLITES; SURFACES; LIGHT; MEDIA AB The opposition effect, the sharp surge in brightness of an astronomical object observed near zero phase angle, which has been known for more than a century, has generally been explained by shadow hiding. The reflectances of several Apollo lunar soil samples have been measured as a function of phase angle in linearly and circularly polarized light. All samples exhibited a decrease in the linear polarization ratio and an increase in the circular polarization ratio in the opposition peak. This provides unequivocal proof that most of the lunar opposition effect is caused by coherent backscatter, not shadow hiding. This result has major implications for the interpretation of photometric observations of bodies in the solar system, including the Earth. C1 JET PROP LAB,PASADENA,CA 91109. RP HAPKE, BW (reprint author), UNIV PITTSBURGH,DEPT GEOL & PLANETARY SCI,PITTSBURGH,PA 15260, USA. NR 38 TC 100 Z9 101 U1 0 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 23 PY 1993 VL 260 IS 5107 BP 509 EP 511 DI 10.1126/science.260.5107.509 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA KY504 UT WOS:A1993KY50400023 PM 17830428 ER PT J AU GLEASON, JF BHARTIA, PK HERMAN, JR MCPETERS, R NEWMAN, P STOLARSKI, RS FLYNN, L LABOW, G LARKO, D SEFTOR, C WELLEMEYER, C KOMHYR, WD MILLER, AJ PLANET, W AF GLEASON, JF BHARTIA, PK HERMAN, JR MCPETERS, R NEWMAN, P STOLARSKI, RS FLYNN, L LABOW, G LARKO, D SEFTOR, C WELLEMEYER, C KOMHYR, WD MILLER, AJ PLANET, W TI RECORD LOW GLOBAL OZONE IN 1992 SO SCIENCE LA English DT Article AB The 1992 global average total ozone, measured by the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus-7 satellite, was 2 to 3 percent lower than any earlier year observed by TOMS (1979 to 1991). Ozone amounts were low in a wide range of latitudes in both the Northern and Southern hemispheres, and the largest decreases were in the regions from 10-degrees-S to 20-degrees-S and 10-degrees-N to 60-degrees-N. Global ozone in 1992 is at least 1.5 percent lower than would be predicted by a statistical model that includes a linear trend and accounts for solar cycle variation and the quasi-biennial oscillation. These results are confirmed by comparisons with data from other ozone monitoring instruments: the SBUV/2 instrument on the NOAA-11 satellite, the TOMS instrument on the Russian Meteor-3 satellite, the World Standard Dobson Instrument 83, and a collection of 22 ground-based Dobson instruments. C1 SOFTWARE CORP AMER,LANHAM,MD 20706. HUGHES STX CORP,LANHAM,MD 20706. UNIV COLORADO,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. NOAA,BOULDER,CO 80303. NOAA,NATL WEATHER SERV,CLIMATE ANAL CTR,CAMP SPRINGS,MD 20031. NOAA,NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,SATELLITE RES LAB,CAMP SPRINGS,MD 20031. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RP GLEASON, JF (reprint author), UNIV SPACE RES ASSOC,CODE 916,GREENBELT,MD 20771, USA. RI Flynn, Lawrence/B-6321-2009; Newman, Paul/D-6208-2012; Gleason, James/E-1421-2012; Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013; Bhartia, Pawan/A-4209-2016 OI Flynn, Lawrence/0000-0001-6856-2614; Newman, Paul/0000-0003-1139-2508; Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462; Bhartia, Pawan/0000-0001-8307-9137 NR 17 TC 265 Z9 270 U1 1 U2 8 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 23 PY 1993 VL 260 IS 5107 BP 523 EP 526 DI 10.1126/science.260.5107.523 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA KY504 UT WOS:A1993KY50400028 PM 17830433 ER PT J AU KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS WILSON, RB VANPARADIJS, J PREECE, RD BRIGGS, MS PENDLETON, GN BROCK, MN KOSHUT, TM HORACK, JM AF KOUVELIOTOU, C FISHMAN, GJ MEEGAN, CA PACIESAS, WS WILSON, RB VANPARADIJS, J PREECE, RD BRIGGS, MS PENDLETON, GN BROCK, MN KOSHUT, TM HORACK, JM TI RECURRENT BURST ACTIVITY FROM THE SOFT GAMMA-RAY REPEATER SGR-1900+14 SO NATURE LA English DT Article ID HIGH-ENERGY TRANSIENT AB OF the one thousand or so detected sources of cosmic gamma-ray bursts (GRBs), only three are known to have exhibited recurrent activity1-4. These events differ from the majority of GRBs in that they are of much shorter duration and have relatively soft spectra5. The recurrent sources can thus be considered as a distinct class of objects the soft gamma repeaters (SGRs). The embryonic distribution of the SGRs suggests that they are of galactic origin4, whereas the distribution6 of GRBs seems to be inconsistent with any known galactic source population. Here we report the detection by the Burst and Transient Source Experiment (BATSE)7 of three short, very soft transient events from a location consistent with that of the 'old' repeater SGR 1900 + 14 (ref. 8). Our results suggest that the SGR active phase lasts at least 13 years, which, in conjunction with the arguments for a galactic origin, lends support to suggestions4,5 that SGRs are neutron stars. C1 UNIV ALABAMA, DEPT PHYS, HUNTSVILLE, AL 35899 USA. ASTRON INST ANTON PANNEKOEK, 1098 SJ AMSTERDAM, NETHERLANDS. CTR HIGH ENERGY ASTROPHYS, 1098 SJ AMSTERDAM, NETHERLANDS. RP KOUVELIOTOU, C (reprint author), NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, ES 66, HUNTSVILLE, AL 35812 USA. RI Horack, John/J-6670-2016 NR 23 TC 95 Z9 95 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 22 PY 1993 VL 362 IS 6422 BP 728 EP 730 DI 10.1038/362728a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA KY450 UT WOS:A1993KY45000047 ER PT J AU KIM, KH CHOI, YS BARNES, NP HESS, RV BAIR, CH BROCKMAN, P AF KIM, KH CHOI, YS BARNES, NP HESS, RV BAIR, CH BROCKMAN, P TI INVESTIGATION OF 2.1-MU-M LASING PROPERTIES OF HO-TM-CR-YAG CRYSTALS UNDER FLASH-LAMP PUMPING AT VARIOUS OPERATING-CONDITIONS SO APPLIED OPTICS LA English DT Article DE SOLID-STATE LASERS; HOLMIUM LASERS; INFRARED LASERS ID LASER; PERFORMANCE; HOLMIUM; GARNETS AB Flash-lamp-pumped normal-mode and Q-switched 2.1-mum laser operations of Ho:Tm:Cr:YAG crystals have been evaluated under a wide variety of experimental conditions in order to determine an optimum lasing condition and to characterize the laser outputs. Q-switched laser-output energies equal to or in some cases more than the normal-mode laser energies were obtained in the form of a strong single spike by optimizing the opening time of a lithium niobate Q switch. The increase of the normal-mode laser slope efficiency was observed with the increase of the Tm concentration from 2.5 to 4.5 at. % at operating temperatures from 120 K to near room temperature. Laser transitions were observed only at 2.098 and 2.091 mum under various conditions. The 2.091-mum laser transition appeared to be dominant at high-temperature operations with low-reflective-output couplers and to have an energy-level assignment from 5313 cm-1 to 534 cm-1 or (and) from 5313 cm-1 to 536 cm-1. C1 HAMPTON UNIV, DEPT PHYS, HAMPTON, VA 23668 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. RI KIM, Kyong Hon/C-8108-2009 NR 38 TC 18 Z9 18 U1 0 U2 6 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 APR 20 PY 1993 VL 32 IS 12 BP 2066 EP 2074 PG 9 WC Optics SC Optics GA KX397 UT WOS:A1993KX39700011 PM 20820345 ER PT J AU FARRUKH, UO BROCKMAN, P AF FARRUKH, UO BROCKMAN, P TI TEMPERATURE DISTRIBUTION IN SIDE-PUMPED AND END-PUMPED LASER CRYSTAL RODS - TEMPORAL AND SPATIAL VARIATIONS SO APPLIED OPTICS LA English DT Article DE TEMPERATURE; TIME DEPENDENT; TRANSIENT; SPATIAL; SOLID-STATE LASERS; END PUMPED; SIDE PUMPED; ANALYTICAL ID SOLID-STATE LASERS; ND-YAG; ENERGY-STORAGE AB Knowledge of the temperature distribution of laser rods end pumped by laser diodes or other laser systems is relevant when thermal stress and crystal damage are expected. The temperature of a multipulsed or continuously pumped laser rod is given as a double-series expression and as a function of time. The mathematical model considers all surface cooling rates, the spatial and temporal variations of the pump beam, and the specific heat and thermal conductivity of the rod material. This eigenfunction expansion representation was employed to predict the spatial and time-dependent quasi-steady-state temperature in Ti:sapphire, Nd:YAG, and Cr:LiSAF laser rods of specific dimensions. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. RP FARRUKH, UO (reprint author), HAMPTON UNIV, DEPT ENGN, HAMPTON, VA 23668 USA. NR 14 TC 18 Z9 19 U1 1 U2 7 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 APR 20 PY 1993 VL 32 IS 12 BP 2075 EP 2081 PG 7 WC Optics SC Optics GA KX397 UT WOS:A1993KX39700012 PM 20820346 ER PT J AU MCGUCKIN, BT MENZIES, RT ESPROLES, C AF MCGUCKIN, BT MENZIES, RT ESPROLES, C TI TUNABLE FREQUENCY STABILIZED DIODE-LASER-PUMPED TM, HO-YLIF(4) LASER AT ROOM-TEMPERATURE SO APPLIED OPTICS LA English DT Note AB A diode-laser-pumped single-frequency thulium holmium yttrium lithium fluoride laser that exhibits a closed-loop stability of a few megahertz and a continuous single-mode tuning range of 800 MHz is described. The laser output power is 25 mW and is tunable over approximately 8 cm-1 at 25-degrees-C. C1 BALL SYST, DIV ENGN, PASADENA, CA 91101 USA. RP MCGUCKIN, BT (reprint author), JET PROP LAB, PASADENA, CA 91109 USA. NR 3 TC 6 Z9 7 U1 1 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 APR 20 PY 1993 VL 32 IS 12 BP 2082 EP 2084 PG 3 WC Optics SC Optics GA KX397 UT WOS:A1993KX39700013 PM 20820347 ER PT J AU SIROTA, JM REUTER, DC MUMMA, MJ AF SIROTA, JM REUTER, DC MUMMA, MJ TI BLOCKED IMPURITY BAND DETECTORS APPLIED TO TUNABLE DIODE-LASER SPECTROSCOPY IN THE 8-MU-M TO 28-MU-M RANGE SO APPLIED OPTICS LA English DT Article AB A novel tunable diode laser spectrometer operating at 8 < lambda < 28 mum is described. A blocked impurity band Si:As chip is employed as detector. This device operates in this wavelength range with high detectivity and adequate frequency response for the high-sensitivity techniques used. A combination of sweep averaging and second-harmonic detection at 22 kHz yielded signal-to-noise ratios of 1200 at lambda > 20 mum. The sensitivity and spectral resolution achieved are 1 order of magnitude better than those of Fourier instruments in this range, with an improvement in instrument time response of approximately 3000. Several molecular bands Of CO2 and N2O are observed for what is, to our knowledge, the first time with this instrument. Examples of spectral line measurements are presented. RP SIROTA, JM (reprint author), NASA, GODDARD SPACE FLIGHT CTR, PLANETARY SYST BRANCH, CODE 693, GREENBELT, MD 20771 USA. RI mumma, michael/I-2764-2013 NR 9 TC 16 Z9 16 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 APR 20 PY 1993 VL 32 IS 12 BP 2117 EP 2121 PG 5 WC Optics SC Optics GA KX397 UT WOS:A1993KX39700022 PM 20820356 ER PT J AU COLIN, P SCHRAMM, DN AF COLIN, P SCHRAMM, DN TI CHEMICAL AND LUMINOSITY EVOLUTION, AND COUNTS OF GALAXIES IN A MERGER MODEL SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ABUNDANCES; GALAXIES, EVOLUTION; GALAXIES, INTERACTIONS; STARS, FORMATION ID SOLAR NEIGHBORHOOD; FAINT GALAXIES; STAR FORMATION; MASS FUNCTION; HALO STARS; RATES; DISK; AGE; NUCLEOSYNTHESIS; METALLICITY AB A merger model is applied to the chemical and luminosity evolution of galaxies. Two aspects are focused on. The first is the problem of abundance ratios as a function of metallicity. The second is related to the luminosity evolution of galaxies. In relation to the former, we calculate the evolution of several chemical elements exploring a broad space of possible star formation rates, including those derived using phenomenological arguments from a multiple merger galaxy formation scenario. We are able to reproduce the observed plateau in the ratio of the abundances of oxygen to iron versus metallicity as a direct consequence of one of the merging SFR used; we have utilized a standard Type II supernovae nucleosynthesis scenario coupled with a reasonable binary model for Type Ia supernovae and its consequent nucleosynthetic yields. Following the consequent luminosity effects in a straightforward way enables the estimation of the evolution of bolometric luminosity. We have used our recently developed code for photometric evolution of galaxies to make a preliminary computation of the number-magnitude relationship, assuming a standard picture of galaxy evolution, in the B and K bands. C1 NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. NATL AUTONOMOUS UNIV MEXICO,INST ASTRON,MEXICO CITY 04510,DF,MEXICO. RP COLIN, P (reprint author), UNIV CHICAGO,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 65 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1993 VL 407 IS 2 BP 510 EP 518 DI 10.1086/172532 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KX399 UT WOS:A1993KX39900006 ER PT J AU TURNER, TJ NANDRA, K ZDZIARSKI, AA JAHODA, K MADEJSKI, GM MARSHALL, F MUSHOTZKY, RF PETRE, R POUNDS, KA SMALE, AP SERLEMITSOS, P WEAVER, K AF TURNER, TJ NANDRA, K ZDZIARSKI, AA JAHODA, K MADEJSKI, GM MARSHALL, F MUSHOTZKY, RF PETRE, R POUNDS, KA SMALE, AP SERLEMITSOS, P WEAVER, K TI BBXRT AND GINGA OBSERVATIONS OF THE SEYFERT-1 GALAXY MARKARIAN 335 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (MARKARIAN 335); GALAXIES, SEYFERT; X-RAYS, GALAXIES ID ACTIVE GALACTIC NUCLEI; X-RAY-SPECTRA; COLD MATTER; COMPACT SOURCES; PAIR PRODUCTION; REFLECTION; EMISSION; CASCADES; VARIABILITY; MKN-335 AB We present new X-ray observations of Mrk 335 in the 0.4-10 keV band using BBXRT and in the 2-20 keV band with Ginga. The BBXRT data show a break to a softer spectrum below approximately 1 keV. The Ginga data show evidence for variability in absorption, uncorrelated with flux changes of the continuum source. The inconsistency between the opacity observed at the iron K edge and at softer X-ray energies implies that the absorber has an ionization state approximately FeXV. We suggest that the nuclear emission can be explained by a self-consistent pair cascade model as developed by Zdziarski et al. and Zdziarski and Coppi, where the compactness parameter inferred from the spectral fits to both data sets is in good agreement with the value calculated from the ratio of observed X-ray luminosity and variability time scale. C1 UNIV SPACE RES ASSOC,COLUMBIA,MD. N COPERNICUS ASTRONOM CTR,WARSAW,POLAND. UNIV MARYLAND,DEPT ASTRON,COLL PK,MD 20742. UNIV LEICESTER,DEPT PHYS,LEICESTER LE1 7RH,ENGLAND. UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE,ENGLAND. RP TURNER, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Jahoda, Keith/D-5616-2012 NR 40 TC 33 Z9 33 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1993 VL 407 IS 2 BP 556 EP 563 DI 10.1086/172537 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA KX399 UT WOS:A1993KX39900011 ER EF