FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Wu, RLC Rai, AK Miyoshi, K AF Wu, RLC Rai, AK Miyoshi, K TI Microstructure, friction, and wear characteristics of the as-deposited and carbon ion-implanted diamond films SO APPLIED PHYSICS LETTERS LA English DT Article AB The microstructure, friction and wear characteristics of the as-deposited and carbon ion (160 keV, 6.7x10(17) ions/cm(2)) implanted polycrystalline diamond films grown by plasma-enhanced chemical vapor deposition were studied. Cross sectional transmission electron microscopy revealed the amorphous nature of the ion bombarded film. Raman peaks of the ion-implanted film are found to be consistent with the noncrystalline carbon. The pin-on-disk technique was used to determine the friction and wear characteristics of the diamond films in an ultrahigh vacuum (10(-7) Pa) at room temperature. Compared to the as-deposited film, considerable reduction in friction and wear of the ion-implanted film was observed. (C) 1996 American Institute of Physics. C1 UNIVERSAL ENERGY SYST INC, DAYTON, OH 45432 USA. NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP K SYST CORP, 1522 MARSETTA DR, DAYTON, OH 45432 USA. NR 12 TC 9 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 1996 VL 68 IS 8 BP 1054 EP 1056 DI 10.1063/1.116246 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500009 ER PT J AU Kim, YJ Busch, R Johnson, WL Rulison, AJ Rhim, WK AF Kim, YJ Busch, R Johnson, WL Rulison, AJ Rhim, WK TI Experimental determination of a time-temperature-transformation diagram of the undercooled Zr41.2Ti13.8CU12.5Ni10.0Be22.5 alloy using the containerless electrostatic levitation processing technique SO APPLIED PHYSICS LETTERS LA English DT Article ID METALLIC-GLASS; NUCLEATION AB High temperature high vacuum electrostatic levitation was used to determine the complete time-temperature-transformation (TTT) diagram of the Zr41.2Ti13.8CU12.5Ni10.0Be22.5 bulk metallic glass forming alloy in the undercooled liquid state. This is the first report of experimental data on the crystallization kinetics of a metallic system covering the entire temperature range of the undercooled melt down to the glass transition temperature. The measured TTT diagram exhibits the expected ''C'' shape. Existing models that assume polymorphic crystallization cannot satisfactorily explain the experimentally obtained TTT diagram. This originates from the complex crystallization mechanisms that occur in this bulk glass-forming system, involving large composition fluctuations prior to crystallization as well as phase separation in the undercooled liquid state below 800 K. (C) 1996 American Institute of Physics. C1 CALTECH,WM KECK LAB ENGN MAT,PASADENA,CA 91125. CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 21 TC 109 Z9 111 U1 0 U2 24 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 FEB 19 PY 1996 VL 68 IS 8 BP 1057 EP 1059 DI 10.1063/1.116247 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500010 ER PT J AU Sun, CJ Yang, JW Chen, Q Khan, MA George, T ChangChien, P Mahajan, S AF Sun, CJ Yang, JW Chen, Q Khan, MA George, T ChangChien, P Mahajan, S TI Deposition of high quality wurtzite GaN films over cubic (111) MgAl2O4 substrates using low pressure metalorganic chemical vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article AB We report the deposition of high quality single-crystal wurtzite GaN films on cubic (111) spinel (MgAl2O4) substrates. The room-temperature electron mobility and the optically pumped stimulated emission threshold for these films are nearly identical to those of films deposited on basal plane sapphire. Using cross sectional high resolution TEM we have determined the following orientation relationship between the film and the substrate: [0001]GaN//[111]MgAl2O4 and [<11(2)over bar 0>]GaN//[110]MgAl2O4. This should provide a common cleavage plane for(111) spinel and the wurtzite GaN films over it. (C) 1996 American Institute of Physics. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. CARNEGIE MELLON UNIV,DEPT MAT SCI & ENGN,PITTSBURGH,PA 15213. RP Sun, CJ (reprint author), APA OPT INC,2950 NE 84TH LANE,BLAINE,MN 55434, USA. NR 7 TC 39 Z9 44 U1 0 U2 2 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 FEB 19 PY 1996 VL 68 IS 8 BP 1129 EP 1131 DI 10.1063/1.115735 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500034 ER PT J AU Szewczyk, ZP Noor, AK AF Szewczyk, ZP Noor, AK TI A hybrid neurocomputing numerical strategy for nonlinear structural analysis SO COMPUTERS & STRUCTURES LA English DT Article ID NEURAL NETWORKS AB A hybrid neurocomputing/numerical strategy is presented for geometrically nonlinear analysis of structures. The strategy combines model-free data processing capabilities of computational neural networks with a Pade approximants-based perturbation technique to predict partial information about the nonlinear response of structures. In the hybrid strategy, multilayer feedforward neural networks are used to extend the validity of solutions by using training samples produced by Fade approximations to the Taylor series expansion of the response function. The range of validity of the training samples is taken to be the radius of convergence of Pade approximants and is estimated by setting a tolerance on the diverging approximants. The norm of a residual vector of unbalanced forces in a given element is used as a measure to assess the quality of network predictions. To further increase the accuracy and the range of network predictions, additional training data are generated by either applying linear regression to weight matrices or expanding the training data by using predicted coefficients in a Taylor series. The effectiveness of the hybrid strategy is assessed by performing large-deflection analysis of a doubly-curved composite panel with a circular cutout, and postbuckling analyses of stiffened composite panels subjected to an in-plane edge shear load. In all the problems considered, the hybrid strategy is used to predict selective information about the structural response, namely the total strain energy and the maximum displacement components only. RP Szewczyk, ZP (reprint author), UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681, USA. NR 31 TC 14 Z9 15 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD FEB 17 PY 1996 VL 58 IS 4 BP 661 EP 677 DI 10.1016/0045-7949(95)00178-J PG 17 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA TH098 UT WOS:A1996TH09800001 ER PT J AU Benedetto, S Divsalar, D Montorsi, G Pollara, F AF Benedetto, S Divsalar, D Montorsi, G Pollara, F TI Algorithm for continuous decoding of turbo codes SO ELECTRONICS LETTERS LA English DT Article DE turbo codes; convolutional codes; decoding AB A new continuous version of the maximum a posteriori algorithm is described and applied to sequence oriented decoding of parallel concatenated convolutional codes. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP POLITECN TORINO, DIPARTIMENTO ELETTR, C DUCA ABRUZZI 24, I-10129 TURIN, ITALY. RI Montorsi, Guido/D-4867-2012; OI benedetto, sergio/0000-0002-7648-5396 NR 4 TC 30 Z9 30 U1 0 U2 0 PU INST ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 EI 1350-911X J9 ELECTRON LETT JI Electron. Lett. PD FEB 15 PY 1996 VL 32 IS 4 BP 314 EP 315 DI 10.1049/el:19960217 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA UL770 UT WOS:A1996UL77000026 ER PT J AU Birn, J Iinoya, F Brackbill, JU Hesse, M AF Birn, J Iinoya, F Brackbill, JU Hesse, M TI A comparison of MHD simulations of magnetotail dynamics SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID IN-CELL METHOD; GEOMAGNETIC TAIL; RECONNECTION; INSTABILITY; EVOLUTION; COMPUTER AB The accuracy of two resistive MHD codes based on very different methods is studied by simulating the same problem of plasmoid formation and ejection in the geomagnetic tail initiated by resistive diffusion, using identical initial and boundary conditions and a 2-D approximation. One of the codes is a modified explicit leapfrog scheme, which has been used extensively in the past for similar problems. The other scheme is an implicit particle-in-cell MHD code (FLIP-MHD). The results from both schemes agree within a few percent in all major characteristics: onset and growth rate of the instability, formation and tailward motion of a plasmoid, scale size of the perturbation and details of the mode structures. FLIP, however, predicts a slightly slower tailward motion of the plasmoid. Both simulations exhibit highly variable earthward flow from the reconnection site with similar averages and similar fluctuation levels, resembling observed bursty bulk flows. Due to differences in the phase of these fluctuations, however, the instantaneous flow may differ in the two simulations. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. NASA,GODDARD SPACE FLIGHT CTR,ELECTRODYNAM BRANCH,GREENBELT,MD 20771. RP Birn, J (reprint author), LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,MS D466,LOS ALAMOS,NM 87545, USA. RI Hesse, Michael/D-2031-2012 NR 18 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 FEB 15 PY 1996 VL 23 IS 4 BP 323 EP 326 DI 10.1029/95GL03857 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TW551 UT WOS:A1996TW55100002 ER PT J AU Khazanov, GV Moore, TE Liemohn, MW Jordanova, VK Fok, MC AF Khazanov, GV Moore, TE Liemohn, MW Jordanova, VK Fok, MC TI Global, collisional model of high-energy photoelectrons SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SUPERTHERMAL ELECTRONS; PLASMASPHERE AB A previously-developed colissional, interhemispheric flux tube model for photoelectrons (PE) [Khazanov et al., 1994] has been extended to three dimensions by including transport due to (E) over right arrow x (B) over right arrow and magnetic gradient-curvature drifts. Using this model, initial calculations of the high-energy (greater than or equal to 50 eV) PE distribution as a function of time, energy, pitch angle, and spatial location in the equatorial plane, are reported for conditions of low geomagnetic activity. To explore both the dynamic and steady behaviors of the model, the simulation starts with the abrupt onset of photoelectron excitation, and is followed to steady state conditions. The results illustrate several features of the interaction of photoelectrons with typical magnetospheric plasmas and fields, including collisional diffusion of photoelectons in pitch angle with flux tube filling, diurnal intensity and pitch angle asymmetries introduced by directional sunlight, and energization of the photoelectron distribution in the evening sector. Cross-field drift is shown to have a long time scale, taking 12 to 24 hours to reach a steady state distribution. Future applications of the model are briefly outlined. C1 UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. RP Khazanov, GV (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,USRA,ES-83,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012; Fok, Mei-Ching/D-1626-2012; Liemohn, Michael/H-8703-2012; OI Moore, Thomas/0000-0002-3150-1137; Liemohn, Michael/0000-0002-7039-2631; Jordanova, Vania/0000-0003-0475-8743 NR 16 TC 18 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 FEB 15 PY 1996 VL 23 IS 4 BP 331 EP 334 DI 10.1029/96GL00148 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TW551 UT WOS:A1996TW55100004 ER PT J AU Dessler, AE Kawa, SR Considine, DB Waters, JW Froidevaux, L Kumer, JB AF Dessler, AE Kawa, SR Considine, DB Waters, JW Froidevaux, L Kumer, JB TI UARS measurements of ClO and NO2 at 40 and 46 km and implications for the model ''ozone deficit'' SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERE; O3 AB We present the first diurnally-resolved measurements of ClO and NO2 at 3.1 and 1.4 hPa, approximately 40 and 46 km. Comparisons between the measurements of ClO and a zero-dimensional box model utilizing standard photochemistry and constrained by Upper Atmosphere Research Satellite (UARS) tracer measurements show that photochemical models overpredict ClO by a factor of two or more at 3.1 hPa and by a factor of 1.5-2.0 at 1.4 hPa. NO2 is well simulated by the model at 3.1 hPa, but systematically overestimated at 1.4 hPa. The model overestimate of ClO results in an overestimate of ozone loss in the upper stratosphere of 10-40%. C1 CALTECH,JET PROP LAB,PASADENA,CA. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. RP Dessler, AE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Kawa, Stephan/E-9040-2012; Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 14 TC 26 Z9 26 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 FEB 15 PY 1996 VL 23 IS 4 BP 339 EP 342 DI 10.1029/96GL00154 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TW551 UT WOS:A1996TW55100006 ER PT J AU Hollandsworth, SM McPeters, RD Flynn, LE AF Hollandsworth, SM McPeters, RD Flynn, LE TI New evidence for ozone depletion in the upper stratosphere - Comments SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article C1 SCA,LANHAM,MD 20706. APPL RES CORP,LANDOVER,MD 20785. RP Hollandsworth, SM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ARC,CODE 916,GREENBELT,MD 20771, USA. RI Flynn, Lawrence/B-6321-2009; McPeters, Richard/G-4955-2013 OI Flynn, Lawrence/0000-0001-6856-2614; McPeters, Richard/0000-0002-8926-8462 NR 5 TC 0 Z9 0 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 FEB 15 PY 1996 VL 23 IS 4 BP 411 EP 412 DI 10.1029/96GL00237 PG 2 WC Geosciences, Multidisciplinary SC Geology GA TW551 UT WOS:A1996TW55100024 ER PT J AU Alain, V Fort, A Barzoukas, M Chen, CT BlanchardDesce, M Marder, SR Perry, JW AF Alain, V Fort, A Barzoukas, M Chen, CT BlanchardDesce, M Marder, SR Perry, JW TI The linear and non-linear optical properties of some conjugated ferrocene compounds with potent heterocyclic acceptors SO INORGANICA CHIMICA ACTA LA English DT Article DE EFISH; non-linear optics; metallocene; organometallic; poling; spectroscopy ID NONLINEARITIES; HYPERPOLARIZABILITIES; DERIVATIVES AB We have synthesized donor-acceptor chromophores containing ferrocene as the donor and several different heterocyclic accepters. In each case the chromophores have an intense band at low energy which is ascribed to a metal to ligand charge-transfer band. Neutral compounds containing the 1,3-diethyl-2-thiobarbituric acid and dicyanomethylene-2, 3-dihydrobenzothiophene-1, 1-dioxide accepters have large first molecular hyperpolarizabilities (beta) in comparison to a previously examined compound 1-ferrocenyl-2-E-(4-nitrophenyl)ethylene, as measured by electric field induced second harmonic generation (EFISH), in chloroform, with 1.907 mu m fundamental radiation. Incorporation of 1-ferrocenyl-4-E,E(4-nitrophenyl)butadiene into polymethylmethacrylate at 2% molar loading, yielded after poling at 100 V mu m(-1), a polymer film with an r(33) = 0.8 pm V-1 measured at 820 nm. C1 CALTECH,BECKMAN INST,PASADENA,CA 91125. ECOLE NORMALE SUPER,DEPT CHIM,URA 1679 CNRS,F-75231 PARIS 05,FRANCE. IPCMS,F-67037 STRASBOURG,FRANCE. CALTECH,JET PROP LAB,PASADENA,CA 91109. RI Chen, Chin-Ti/E-5341-2015 NR 22 TC 79 Z9 79 U1 1 U2 9 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD FEB 15 PY 1996 VL 242 IS 1-2 BP 43 EP 49 DI 10.1016/0020-1693(95)04847-2 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UM311 UT WOS:A1996UM31100008 ER PT J AU Ahumada, AJ Beard, B Watson, AB AF Ahumada, AJ Beard, B Watson, AB TI Image discrimination models with contrast gain control predict target detection in fixed and random noise SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF BERKELEY,SCH OPTOMETRY,BERKELEY,CA 94720. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 1060 EP 1060 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39701058 ER PT J AU Mulligan, JB AF Mulligan, JB TI Perception and pursuit of velocity perturbations SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 1991 EP 1991 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39701989 ER PT J AU Stone, LS Perrone, JA AF Stone, LS Perrone, JA TI Translation and rotation trade off in human visual heading estimation. SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV WAIKATO,DEPT PSYCHOL,WAIKATO,NEW ZEALAND. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 2359 EP 2359 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39702362 ER PT J AU Beard, BL Klein, SA Ahumada, AJ Slotnick, SD AF Beard, BL Klein, SA Ahumada, AJ Slotnick, SD TI Training on a vernier acuity task does transfer to untrained retinal locations SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,SCH OPTOMETRY,BERKELEY,CA. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 3180 EP 3180 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39703176 ER PT J AU Post, RB Welch, RB AF Post, RB Welch, RB TI Simultaneous opposite adaptations to altered visual-vestibular feedback contingent on head rotation frequency SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV CALIF DAVIS,DEPT PSYCHOL,DAVIS,CA 95616. NASA,AMES RES CTR,MT VIEW,CA. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 3266 EP 3266 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39703261 ER PT J AU Beutter, BR Stone, LS AF Beutter, BR Stone, LS TI Quantifying the correlation between eye-movement and perceptual responses to moving plaids SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 3375 EP 3375 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39703370 ER PT J AU Verghese, P Stone, LS AF Verghese, P Stone, LS TI The effect of spatial layout on perceived speed SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 3436 EP 3436 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39703431 ER PT J AU DellaVecchia, MA Ansari, R Suh, K Dublin, S AF DellaVecchia, MA Ansari, R Suh, K Dublin, S TI Dynamic light scattering for the measurement of cataractogenesis SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 WILLS EYE HOSP & RES INST,PHILADELPHIA,PA. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. DREXEL UNIV,PHILADELPHIA,PA 19104. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 3456 EP 3456 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39703451 ER PT J AU Thompson, P Stone, LS AF Thompson, P Stone, LS TI Contrast dependence of perceived flicker rate: Counterphase gratings dont behave like drifting gratings. SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV YORK,DEPT PSYCHOL,YORK YO1 5DD,N YORKSHIRE,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. 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 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 4168 EP 4168 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39704162 ER PT J AU Wang, LP Koblinsky, CJ AF Wang, LP Koblinsky, CJ TI Low-frequency variability in the region of the Agulhas retroflection SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SOUTH-ATLANTIC; KUROSHIO EXTENSION; ROSSBY WAVES; OCEAN; CIRCULATION; BALANCE; WATER; THERMOCLINE; TRANSPORT; EDDIES AB Using sea level data collected by TOPEX/POSEIDON altimeter, we studied the low-frequency variability in the region of the Agulhas Retroflection and Return Current. We found that characteristics of the low-frequency variability are fundamentally different from those associated with the high-frequency mesoscale variability, As in the Kuroshio Extension region, strong low-frequency variability is found to duster around strong current. Although bottom topography is found to have strong influence on the low-frequency variability, correspondence between the spatial structure of low-frequency variability and major bottom topographic features is significantly different from that in the Kuroshio Extension region. RP Wang, LP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 971,GREENBELT,MD 20771, USA. NR 36 TC 8 Z9 8 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1996 VL 101 IS C2 BP 3597 EP 3614 DI 10.1029/95JC03124 PG 18 WC Oceanography SC Oceanography GA TW390 UT WOS:A1996TW39000012 ER PT J AU McClain, CR Arrigo, K Tai, KS Turk, D AF McClain, CR Arrigo, K Tai, KS Turk, D TI Observations and simulations of physical and biological processes at ocean weather station P, 1951-1980 SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SUBARCTIC PACIFIC-OCEAN; CENTRAL NORTH PACIFIC; MIXED LAYER; PHYTOPLANKTON GROWTH; MODEL; TEMPERATURE; PLANKTON; WATERS; MATTER; SEA AB Physical and biological processes in the mixed layer at ocean weather station (OWS) P (50 degrees N, 145 degrees W) over a 30-year period (1951-1980) were investigated using observations and model simulations. The observations include 30 years of surface meteorological and sea surface temperature data collected at OWS P and Ekman upwelling velocities derived from the Comprehensive Ocean-Atmosphere Data Set, 14 years (1953-1966) of daily temperature profiles, nearly 150 chlorophyll a profiles spanning all months of the year, monthly climatological solar irradiances, and 0- to 50-m integrated nitrate concentrations, The simulations incorporated models for the estimation of surface solar downwelling irradiance, surface heat fluxes, subsurface diffuse attenuation, mixed layer dynamics, and biological processes. The time-dependent model inputs were the surface observations of cloud cover, air temperature, dew point temperature, and wind speed. The atmospheric irradiance, marine diffuse attenuation, and mixed layer models were adapted from existing models developed by others. The biological model, developed by the authors, has four components (nitrate, ammonium, phytoplankton nitrogen, and zooplankton nitrogen) and computes a variety of additional quantities including chlorophyll a concentration and gross and new production. Model comparisons with in situ time series showed that predictions of sea surface temperature and mixed layer depth were reasonably accurate. Climatological monthly profiles of chlorophyll a and temperature were within 1 standard deviation of the observed values at nearly all depths. Also, the climatological annual cycles of solar irradiance and 0- to 50-m integrated nitrate accurately reproduced observed values. Annual primary production was estimated to be similar to 190 g C m(-2) yr(-1) and varied by no more than +/-5% in any year. This estimate is consistent with recent observations but is much greater than earlier estimates, indicating that carbon cycling in the North Pacific is much more important to the global carbon budget than previously thought. Significant interannual variability in sea surface temperature, Ekman upwelling, mixed layer depth, and surface nitrate concentration had little impact on productivity. The model also indicates that the nitrate supply to the euphotic zone is very sensitive to Ekman upwelling and that amplification of the wind stress curl can result in complete nitrate depletion when the winds are persistently downwelling favorable. C1 GEN SCI CORP,LAUREL,MD 20707. DALHOUSIE UNIV,DEPT OCEANOG,HALIFAX,NS B3H 4J1,CANADA. RP McClain, CR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,CODE 9710,GREENBELT,MD 20771, USA. NR 80 TC 55 Z9 55 U1 1 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 FEB 15 PY 1996 VL 101 IS C2 BP 3697 EP 3713 DI 10.1029/95JC03052 PG 17 WC Oceanography SC Oceanography GA TW390 UT WOS:A1996TW39000018 ER PT J AU Glazman, RE Fabrikant, A Srokosz, MA AF Glazman, RE Fabrikant, A Srokosz, MA TI Numerical analysis of the sea state bias for satellite altimetry SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GENERATED GRAVITY-WAVES; ELECTROMAGNETIC BIAS; RADAR ALTIMETRY; EQUILIBRIUM RANGE; GEOMETRY; SPECTRUM AB Theoretical understanding of the dependence of sea state bias (SSB) on wind wave conditions has been achieved only for the case of a unidirectional wind-driven sea [Jackson, 1979; Rodriguez et al:, 1992; Glazman and Srokosz, 1991]. Recent analysis of Geosat and TOPEX altimeter data showed that additional factors, such as swell, ocean currents, and complex directional properties of realistic wave fields, may influence SSB behavior. Here we investigate effects of two-dimensional multimodal wave spectra using a numerical model of radar reflection from a random, non-Gaussian surface. A recently proposed ocean wave spectrum is employed to describe sea surface statistics. The following findings appear to be of particular interest: (1) Sea swell has an appreciable effect in reducing the SSB coefficient compared with the pure wind sea case but has less effect on the actual SSB owing to the corresponding increase in significant wave height. (2) Hidden multimodal structure (the two-dimensional wavenumber spectrum contains separate peaks, for swell and wind seas, while the frequency spectrum looks unimodal) results in an appreciable change of SSB. (3) For unimodal, purely wind-driven seas, the influence of the angular spectral width is relatively unimportant; that is, a unidirectional sea provides a good qualitative model for SSB if the swell is absent. (4) The pseudo wave age is generally much better for parametrizing the SSB coefficient than the actual wave age (which is ill-defined for a multimodal sea) or wind speed. (5) SSB can be as high as 5% of the significant wave height, which is significantly greater than predicted by present empirical model functions tuned on global data sets. (6) Parameterization of SSB in terms of wind speed is likely to lead to errors due to the dependence on the (in practice, unknown) fetch. C1 PENN STATE UNIV,DEPT METEOROL,UNIVERSITY PK,PA 16802. CHILWORTH RES CTR,JAMES RENNELL CTR OCEAN CIRCULAT,REMOTE SENSING APPLICAT DEV UNIT,SOUTHAMPTON SO1 7NS,HANTS,ENGLAND. RP Glazman, RE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 29 TC 14 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1996 VL 101 IS C2 BP 3789 EP 3799 DI 10.1029/95JC03619 PG 11 WC Oceanography SC Oceanography GA TW390 UT WOS:A1996TW39000025 ER PT J AU Krisher, TP AF Krisher, TP TI Gravitational redshift in a local freely falling frame: A proposed new null test of the equivalence principle SO PHYSICAL REVIEW D LA English DT Article ID DARK MATTER; MACROSCOPIC FORCES; NONMETRIC THEORIES; INERTIAL FRAMES; GRAVITY; CLOCK; GALILEO AB We consider the gravitational redshift effect measured by an observer in a local freely falling frame (LFFF) in the gravitational field of a massive body. For purely metric theories of gravity, the metric in a LFFF is expected to differ from that of flat spacetime by only ''tidal'' terms of order (GM/c(2)R)(r'/R)(2), where R is the distance of the observer from the massive body, and r' is the coordinate separation relative to the origin of the LFFF. A simple derivation shows that a violation of the equivalence principle for certain types of ''clocks'' could lead to a larger apparent redshift effect of order (1-alpha)(GM/c(2)R)(r'/R), where alpha parametrizes the violation (alpha=1 for purely metric theories, such as general relativity). Therefore, redshift experiments in a LFFF with separated clocks can provide a new null test of the equivalence principle. With presently available technology, it is possible to reach an accuracy of 0.01% in the gravitational field of the Sun using an atomic clock orbiting the Earth. A 1% test in the gravitational field of the galaxy would be possible if an atomic frequency standard were flown on a space mission to the outer solar system. RP Krisher, TP (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 38 TC 7 Z9 7 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1996 VL 53 IS 4 BP R1735 EP R1739 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TW982 UT WOS:A1996TW98200001 ER PT J AU Hua, F Grugel, RN AF Hua, F Grugel, RN TI Direct observation of the columnar to equiaxed zone transition in an undercooled melt SO SCRIPTA MATERIALIA LA English DT Article ID NH4CL-H2O ANALOG CASTINGS; MICROSTRUCTURE FORMATION; MODEL ASPECTS; GROWTH; ALLOYS; FRONT C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. RP Hua, F (reprint author), VANDERBILT UNIV,CTR MICROGRAV RES & APPLICAT,POB 6079-B,NASHVILLE,TN 37235, USA. NR 24 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD FEB 15 PY 1996 VL 34 IS 4 BP 573 EP 577 DI 10.1016/1359-6462(95)00557-9 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA TT482 UT WOS:A1996TT48200009 ER PT J AU GrimmBosbach, T Thummel, HT Nesbet, RK Peyerimhoff, SD AF GrimmBosbach, T Thummel, HT Nesbet, RK Peyerimhoff, SD TI Calculation of cross sections for rovibrational excitation of N-2 by electron impact SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID MATRIX PROPAGATION PROGRAM; MOLECULE-SCATTERING; DIFFERENTIAL-EQUATIONS; VIBRATIONAL-EXCITATION; ROTATIONAL-EXCITATION; COLLISIONS; APPROXIMATION; RESONANCE; REGION; N2 AB Rovibronic cross sections for the excitation of various rotational and vibrational levels of N-2 by electron impact for scattering energies in the range of 1-4 eV have been calculated in the framework of the R-matrix approach. The new non-adiabatic phase matrix method (NADP) is employed for the nuclear vibrations. The results are compared with experiment and with other theoretical data and are found to be in excellent agreement with measurements in the energy region of the (2) Pi(g) shape resonance. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95120. RP GrimmBosbach, T (reprint author), UNIV BONN,INST PHYS & THEORET CHEM,WEGELERSTR 12,D-53115 BONN,GERMANY. NR 29 TC 8 Z9 8 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD FEB 14 PY 1996 VL 29 IS 3 BP L105 EP L112 DI 10.1088/0953-4075/29/3/004 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TW913 UT WOS:A1996TW91300004 ER PT J AU McKenna, JT AF McKenna, JT TI Upgraded shuttle engines grounded SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT News Item RP McKenna, JT (reprint author), NASA,KENNEDY SPACE CTR,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD FEB 12 PY 1996 VL 144 IS 7 BP 24 EP 24 PG 1 WC Engineering, Aerospace SC Engineering GA TU742 UT WOS:A1996TU74200012 ER PT J AU Friedrich, S Segall, K Gaidis, MC Toledano, DS Prober, DE Szymkowiak, AE Moseley, SH AF Friedrich, S Segall, K Gaidis, MC Toledano, DS Prober, DE Szymkowiak, AE Moseley, SH TI Superconducting Nb-Ta-Al-AlOx-Al X-ray detectors with spatial resolution SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID JUNCTIONS AB Superconducting X-ray detectors based on SIS tunnel junctions offer potential for high spectral resolution and single photon efficiency. When used in a double junction geometry, they also offer spatial resolution needed for focal plane imaging. We are developing Nb-Ta-Al-AlOx-Al detectors for space-based X-ray astronomy applications. The design employs superconductor bandgap engineering for improved charge collection and adaptability for double junction geometries. For irradiation of a single junction device with 6 keV X-rays at a single location, the detectors have an energy resolution of 87 eV at 0.27 K. Initial studies of double junction detectors show a spectral resolution of 178 eV and an inferred spatial resolution of 4 mu m over an effective length of 60 mu m. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Friedrich, S (reprint author), YALE UNIV,DEPT APPL PHYS,BOX 2157 YALE STN,NEW HAVEN,CT 06520, USA. RI Moseley, Harvey/D-5069-2012; Gaidis, Michael/D-3327-2013 NR 10 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 44 EP 46 DI 10.1016/0168-9002(95)01053-X PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400015 ER PT J AU Stahle, CK Kelley, RL McCammon, D Moseley, SH Szymkowiak, AE AF Stahle, CK Kelley, RL McCammon, D Moseley, SH Szymkowiak, AE TI Microcalorimeter arrays for high resolution soft X-ray spectroscopy SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID CALORIMETERS AB We have produced monolithic silicon detector arrays comprising 36 one-square-millimeter microcalorimeter pixels capable of achieving a resolution of similar to 8 eV FWHM for soft X-rays. Each silicon pixel is suspended by silicon beams that provide a weak link to a similar to-60 mK heat sink. The thermometer element of each pixel is an ion-implanted thermistor. X-ray thermalization is achieved in a 1 mu m absorbing layer of MOCVD-grown HgTe. The HgTe is grown on thin Si substrates that are individually attached to the array elements using epoxy. We have determined that the value of the conductance of the link between absorber and thermometer critically affects device performance. We have performed preliminary investigations using arrays with small suspended absorber isolators etched in the center of each pixel. When an absorber is attached to the center of an absorber isolator, the beams supporting that isolator provide the thermal link to the rest of the pixel. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. RP Stahle, CK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Moseley, Harvey/D-5069-2012; Kelley, Richard/K-4474-2012 NR 6 TC 36 Z9 36 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 173 EP 176 DI 10.1016/0168-9002(95)01096-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400058 ER PT J AU Barnes, PD DaSilva, A Akerib, DS Bauer, D Brink, P Cabrera, B Caldwell, DO Chugg, B Clarke, RM Cummings, A Davies, A Diaz, RC Dougherty, BL Emes, J Golwala, SR Hale, D Haller, EE Irwin, KD Knowlton, WB Kuziminov, V Lu, A Nam, SW Penn, MJ Novikov, V Pritychenko, BV Queinnec, F Ross, RR Sadoulet, B Seitz, D Shutt, T Smith, A Smith, G Sonnenschein, A Stockwell, W Taylor, JD Therrien, R Trumbull, TL White, S Wolgast, RC Yellin, S Young, BA AF Barnes, PD DaSilva, A Akerib, DS Bauer, D Brink, P Cabrera, B Caldwell, DO Chugg, B Clarke, RM Cummings, A Davies, A Diaz, RC Dougherty, BL Emes, J Golwala, SR Hale, D Haller, EE Irwin, KD Knowlton, WB Kuziminov, V Lu, A Nam, SW Penn, MJ Novikov, V Pritychenko, BV Queinnec, F Ross, RR Sadoulet, B Seitz, D Shutt, T Smith, A Smith, G Sonnenschein, A Stockwell, W Taylor, JD Therrien, R Trumbull, TL White, S Wolgast, RC Yellin, S Young, BA TI Installation of the Cryogenic Dark Matter Search (CDMS) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID UNIVERSE; LIMITS AB We discuss the status of a cryogenic dark matter search beginning operation in the Stanford Underground Facility. The detectors will be cooled in a specially designed cryostat connected to a modified side access Oxford 400 dilution refrigerator. We discuss two detector designs and performance, the cryostat construction and operation, and the multi-level shield surrounding the cryostat. Finally, we will examine the limits which we will be able to set on WIMP dark matter with this experiment. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV BRITISH COLUMBIA,DEPT PHYS,VANCOUVER,BC V5Z 1M9,CANADA. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. CALTECH,JET PROP LAB,PASADENA,CA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RUSSIAN ACAD SCI,INST NUCL RES,BAKSAN NEUTRINO OBSERV,MOSCOW,RUSSIA. CARLETON UNIV,CRPP,OTTAWA,ON K1S 5B6,CANADA. MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824. UNIV SANTA CLARA,DEPT PHYS,SANTA CLARA,CA 95053. RP Barnes, PD (reprint author), UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,301 LE CONTE HALL,BERKELEY,CA 94720, USA. NR 19 TC 30 Z9 30 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 233 EP 236 DI 10.1016/0168-9002(95)01094-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400079 ER PT J AU Egelhof, P Beyer, HF McCammon, D vonFeilitzsch, F vonKienlin, A Kluge, HJ Liesen, D Meier, J Moseley, SH Stohlker, T AF Egelhof, P Beyer, HF McCammon, D vonFeilitzsch, F vonKienlin, A Kluge, HJ Liesen, D Meier, J Moseley, SH Stohlker, T TI Application of low temperature calorimeters for precise Lamb shift measurements on hydrogen-like very heavy ions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID X-RAY SPECTROSCOPY AB The precise determination of the 2s(1/2), 2p(1/2), 2p(3/2) --> 1s(1/2) X-ray transitions in hydrogen-like very heavy ions such as Pb-208(81+) or U-238(91+) provides a sensitive test of QED, especially of higher order contributions to the self-energy which are not accessible by alternative methods. Such measurements became possible recently by X-ray spectroscopy using highly charged ions stored and cooled in heavy ion storage rings. A better energy resolution of the X-ray detector is most essential in order to improve the experimental accuracy, which is presently about one order of magnitude worse than the theoretical uncertainty. An energy resolution of Delta E = 30-50 eV for E(y) = 50-100 keV, and a photopeak efficiency above 30% may be provided by a low temperature calorimeter, It will be constructed on the basis of already existing arrays of silicon microcalorimeters, but with larger volume and high Z absorbers. Such a detector will allow a more precise determination of the 1s-lamb shift and for the first time the direct investigation of the 2s-Lamb shift in hydrogen-like heavy ions. In the present contribution the experimental scenario for QED experiments at storage rings, the present status of experimental and theoretical investigations and the design of an appropriate low temperature detector are discussed. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. TECH UNIV MUNICH,D-85747 GARCHING,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Egelhof, P (reprint author), GSI DARMSTADT,POSTFACH 110552,PLANCKSTR 1,D-64220 DARMSTADT,GERMANY. RI Moseley, Harvey/D-5069-2012 NR 12 TC 17 Z9 17 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 263 EP 265 DI 10.1016/0168-9002(95)01105-6 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400088 ER PT J AU McCammon, D Almy, R Deiker, S Morgenthaler, J Kelley, RL Marshall, FJ Moseley, SH Stahle, CK Szymkowiak, AE AF McCammon, D Almy, R Deiker, S Morgenthaler, J Kelley, RL Marshall, FJ Moseley, SH Stahle, CK Szymkowiak, AE TI A sounding rocket payload for X-ray astronomy employing high-resolution microcalorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern AB We have completed a sounding rocket payload that will use a 36 element array of microcalorimeters to obtain a high-resolution spectrum of the diffuse X-ray background between 0.1 and 1 keV. This experiment uses only mechanical collimation of the incoming X-rays, but the cryostat and detector assembly have been designed to be placed at the focus of a conical foil imaging mirror which will be employed on subsequent flights to do spatially resolved spectroscopy of supernova remnants and other extended objects. The detector system is a monolithic array of silicon calorimeters with ion-implanted thermometers and HgTe X-ray absorbers. The 1 mm(2) pixels achieve a resolution of about 8 eV FWHM operating at 60 mK. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP McCammon, D (reprint author), UNIV WISCONSIN,DEPT PHYS,1150 UNIV AVE,MADISON,WI 53706, USA. RI Moseley, Harvey/D-5069-2012; Kelley, Richard/K-4474-2012 NR 7 TC 46 Z9 46 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 266 EP 268 DI 10.1016/0168-9002(95)01106-4 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400089 ER PT J AU Colombi, S Dodelson, S Widrow, LM AF Colombi, S Dodelson, S Widrow, LM TI Large-scale structure tests of warm dark matter SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmology, theory; dark matter; large-scale structure of universe; methods, numerical ID GRAVITATIONAL-INSTABILITY; NEUTRINO OSCILLATIONS; DENSITY-FLUCTUATIONS; COSMOLOGICAL BOUNDS; VELOCITY DISPERSION; DOMINATED UNIVERSE; MASSIVE NEUTRINOS; GALAXY REDSHIFTS; CFA SURVEY; CONSTRAINTS AB The nature of the dark matter critically affects the large-scale structure of the universe. Under the assumptions that the universe is spatially flat with zero cosmological constant and that primordial perturbations were adiabatic with a Harrison-Zeldovich spectrum, neither hot dark matter (HDM) nor cold dark matter (CDM) appears consistent with the observed large-scale structure. Warm dark matter (WDM) is an intriguing alternative from the point of view of both cosmology and particle physics. We consider a one-parameter family of WDM models. The linear power spectra for these models is calculated and compared with the corresponding spectra for CDM, HDM, and mixed dark matter (MDM), as well as the power spectrum derived from observations. Our linear analyses suggest that a model universe dominated by a particle whose mass-to-temperature ratio m(x)/T-x is increased by a factor of 2 as compared with the standard HDM neutrino gives a reasonable fit to the data on large (>8 h(-1) Mpc) scales. N-body simulations for this particular WDM model show features of both HDM and CDM. As in HDM, the first objects to collapse are large pancake-like structures. The final matter distribution is rather smooth, and structures as small as galaxy halos are excluded. However, there appear to be virialized rich clusters evident in the CDM but not in the HDM simulations. Unfortunately, a simple comparison of the matter distribution and its statistical properties with observations indicates that WDM, like CDM, has too much power at small scales. This is particularly evident in the small-scale pairwise velocity dispersion. The cluster multiplicity function has the wrong shape, with too many rich clusters being produced, although this conclusion is based on the simple assumption that light traces mass in groups of galaxies. C1 QUEENS UNIV,DEPT PHYS,KINGSTON,ON K7L 3N6,CANADA. RP Colombi, S (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 105 TC 118 Z9 118 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 FEB 10 PY 1996 VL 458 IS 1 BP 1 EP 17 DI 10.1086/176788 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500001 ER PT J AU Michalitsianos, AG Oliversen, RJ Maran, SP AF Michalitsianos, AG Oliversen, RJ Maran, SP TI Far-UV spectral variability in the gravitational lens candidate UM 425 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; quasars, absorption lines; quasars, individual (UM4 425, Q1120+019); ultraviolet, galaxies ID ABSORPTION; EMISSION; QUASARS; LINES AB A comparison of recently acquired far-UV spectra with data obtained nearly 10 months earlier indicates changes have occurred in both absorption and ionization levels associated with Broad Absorption Line (BAL) structure in the QSO UM 425, a candidate gravitationally lensed system. These observations are compared with the initial discovery of O VI and N V BAL structure previously found with the international Ultraviolet Explorer (IUE), that suggests outflow of highly ionized material with speeds up to similar to -12,000 km s(-1) in the QSO (z = 1.471) rest frame. Discrete absorption components in the O VI BAL trough, occurring at velocity intervals of similar to 2100 km s(-1) up to the terminal speed, are also evident in the Lyman-alpha lambda 1216 line profile, which is affected by similar absorption structures within the velocity-broadened N V lambda 1240 BAL trough. The greatest temporal change in relative optical depth occurs at velocity intervals which correspond to the BAL absorption components. Significantly, a decrease in O VI BAL absorption over the entire BAL velocity range was accompanied by both an increase in ionization level, indicated by enhanced O VI emission, and by a strengthening of other moderate-to high-excitation emission lines, that include S VI(1) lambda lambda 937,945, C III(1) lambda 977, N III(1) lambda 990, and S IV(1) lambda lambda 1063,1073. These observations are relevant to time-delay studies of UM 425 because the temporal changes observed in intrinsic QSO ionization are small compared with the estimated delay time between the images in the system. C1 NASA,GODDARD SPACE FLIGHT CTR,SPACE SCI DIRECTORATE,GREENBELT,MD 20771. RP Michalitsianos, AG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 684-1,GREENBELT,MD 20771, USA. NR 26 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 FEB 10 PY 1996 VL 458 IS 1 BP 67 EP 72 DI 10.1086/176793 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500006 ER PT J AU Weaver, KA Nousek, J Yaqoob, T Mushotzky, RF Makino, F Otani, C AF Weaver, KA Nousek, J Yaqoob, T Mushotzky, RF Makino, F Otani, C TI X-ray reprocessing by a molecular torus in the SEYFERT 1.9 galaxy NGC 2992 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (NGC 2992); galaxies, nuclei; galaxies, Seyfert; X-rays, galaxies ID ACTIVE GALACTIC NUCLEI; COLD MATTER; LINE; EMISSION; SPECTRA; VARIABILITY; REFLECTION; LUMINOSITY; NGC-4151; NGC-2992 AB We present new X-ray spectral data for the Seyfert 1.9 galaxy NGC 2992 obtained with the Advanced Satellite for Cosmology and Astrophysics (ASCA). These data are combined with archival and published data to outline a 16 year history of flux variability in the X-ray band. We find that, while the 2-10 keV flux has decreased by a factor of similar to 20 in 16 yr, the flux of the Fe K alpha fluorescence line has decreased by only a factor of 2-3, and the inferred amount of Compton reflection is 5 times stronger compared to the continuum than 16 yr ago. From the delay in the response of the Fe K line and inferred Compton reflection to decreases in the continuum flux, we estimate that the reprocessed flux lags the continuum flux by similar to 10 yr, giving a distance of similar to 3.2 pc to the reprocessor. The observed time delay, along with the fact that the Fe K line is narrow (< 6600 km s(-1) FWHM), essentially rules out reprocessing in an accretion disk. This implies the existence of dense, neutral gas with N-H - 10(23)-10(25) Cm-2 within the central regions of the galaxy in addition to a disk, as might be expected for a molecular torus. We find that the flux in the similar to 0.1-4 keV soft X-ray band has decreased by a factor of similar to 15 in 14 yr, similar to the flux in the 2-10 keV band. In addition, the ASCA data, when combined with prior spectral results, imply the presence of a soft excess that is well modeled with partial covering of the nuclear continuum source. We have searched for and found no significant evidence for extended X-ray emission in the ROSAT HRI image of NGC 2992. This lack of extent, coupled with the observed long-term variability of the soft X-ray flux and spectral results for the soft excess, imply that the soft X-ray emission from NGC 2992 is nuclear in origin and is not due to scattering. C1 PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,DAVEY LAB 525,UNIVERSITY PK,PA 16802. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. RIKEN,INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. UNIV SPACE RES ASSOC,COLUMBIA,MD. RI Otani, Chiko/A-6510-2016 NR 59 TC 59 Z9 59 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 FEB 10 PY 1996 VL 458 IS 1 BP 160 EP 171 DI 10.1086/176800 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500013 ER PT J AU Daugherty, JK Harding, AK AF Daugherty, JK Harding, AK TI Gamma-ray pulsars: Emission from extended polar cap cascades SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, theory; pulsars, general; radiation mechanisms, nonthermal ID STRONG MAGNETIC-FIELDS; RAPIDLY SPINNING PULSARS; TRIPLET PAIR PRODUCTION; SOFT PHOTON FIELD; COMPTON-SCATTERING; ULTRARELATIVISTIC ELECTRONS; ENERGETIC RADIATION; VELA PULSAR; GAPS; GEMINGA AB We have used a Monte Carlo simulation of a polar cap (PC) model of gamma-ray pulsars to estimate light curves and phase-resolved spectra for sources whose rotational and magnetic axes are oriented so that only one of the magnetic poles produces emission directed at Earth. In this single polar cap (SPC) scenario, even sources whose light curves have two distinct peaks (Crab, Vela, Geminga, and PSR B1951+32) are due to emission concentrated near the rim of a single PC. If the inclination alpha is comparable to the half-width of the PC gamma-beam, alpha similar to theta(b), the peak-to-peak phase separation can have the large values (similar to 0.4-0.5) observed from these sources. In the model presented here we attribute the observed interpeak emission to pair cascades above the PC interior. Our simulation assumes the physics of conventional PC models, in which the gamma-rays are due to photon-pair cascades initiated by curvature radiation from the acceleration of electrons above the PCs. In this work we assume that the acceleration occurs over a finite region that may extend up to several radii above the neutron star surface. We find that the combined effects of moderately enlarged PC dimensions and extended acceleration zones resolve a major difficulty with earlier PC models, namely their small beamwidths (and hence small detection probabilities). Our best fits to the observed light curves are obtained from models in which the accelerated electrons have a uniform surface density over the PC interior and a sharp density increase of similar to 3-5 near the rim. Based on these assumptions, our model results for Vela reproduce key features of the light curves and phase-resolved spectra. We also consider the compatibility of the model with observations at X-ray, radio, and optical wavelengths. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP Daugherty, JK (reprint author), UNIV N CAROLINA,DEPT COMP SCI,ASHEVILLE,NC 28804, USA. RI Harding, Alice/D-3160-2012 NR 56 TC 281 Z9 281 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 FEB 10 PY 1996 VL 458 IS 1 BP 278 EP 292 DI 10.1086/176811 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500024 ER PT J AU Huang, M Sion, EM Hubeny, I Cheng, FH Szkody, P AF Huang, M Sion, EM Hubeny, I Cheng, FH Szkody, P TI Hubble Space Telescope FOS spectroscopy of VW Hydri in superoutburst SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; novae, cataclysmic variables; stars, individual (VW Hydri); ultraviolet, stars; white dwarfs ID ACCRETION DISK MODEL; CATACLYSMIC VARIABLES; DWARF NOVAE; WHITE-DWARF; IUE OBSERVATIONS; WX-HYDRI; ULTRAVIOLET; INSTABILITY; ATMOSPHERES; EVOLUTION AB We present an analysis of two HST/FOS UV spectra of the SU UMa type dwarf nova, VW Hyi, obtained on 1993 October 24, similar to 5 days after the optical rise of a superoutburst. The absorption features in the first spectrum appear to consist of two components: a broad-winged component (with velocity width of similar to 3000 km s(-1)) and a sharp core narrow component. This is the first time the narrow core is clearly resolved in superoutburst spectra of a dwarf nova system. The sharp core appears absent in the second spectrum obtained similar to 10 minutes later. The broader component is mainly from the accretion disk. By comparing the spectra with a grid of LTE model accretion disk atmospheres constructed with TLUSTY, SYNSPEC, and DISKSYN, we present two possible disk fits to the observed spectra: a steady state disk with solar abundance and M = 3 x 10(-9) M. yr(-1) which can account for all the broad absorption features except for N v lambda 1240, and a model with a discontinuous T-eff(r) distribution in which there is a contribution to the N v lambda 1240 absorption feature. We provide arguments supporting the possibility that the sharp cores are due to gas streams in the system. We also point out the far less likely possibility that the sharp cores form in a hot, high-gravity atmosphere. The synthetic fitting results may imply that the hot matter is accreted from the inner part of the disk onto the surface of the white dwarf through a highly inhomogeneous gas flow. We relate this discussion to our FOS detection of highly asymmetric inverse P Cygni profile structure in the narrow stellar components at C IV lambda 1550. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. UNIV WASHINGTON,DEPT ASTRON,FM 20,SEATTLE,WA 98195. RP Huang, M (reprint author), VILLANOVA UNIV,DEPT ASTRON & ASTROPHYS,VILLANOVA,PA 19085, USA. NR 42 TC 25 Z9 25 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 FEB 10 PY 1996 VL 458 IS 1 BP 355 EP 362 DI 10.1086/176818 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500031 ER PT J AU Martin, CF Rubincam, DP AF Martin, CF Rubincam, DP TI Effects of Earth albedo on the LAGEOS I satellite SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SEMIMAJOR AXIS; ORBIT; RADIATION; PERTURBATIONS; ALGORITHMS; BUDGET; DRAG AB For several pears, Earth albedo has been one of the leading candidates for explaining the anomalous along-track acceleration experienced by the LAGEOS satellites, with reasonable reflection models having been shown to give acceleration peaks comparable to those observed. The effects of Earth albedo on LAGEOS I have been studied for the period March 1985 to June 1989, during which time measurements of reflected radiation from the Earth were made by one to three Earth Radiation Budget Experiment (ERBE) satellites. Data taken during this experiment were processed into hourly radiation exitances for the entire Earth divided into 2.5 degrees x 2.5 degrees blocks. These ERBE data were used, along with detailed models of reflectance characteristics of the Earth, to calculate the accelerations which reflected radiation would induce on LAGEOS I. The along-track component of the acceleration was averaged over 10 revolutions in order to average out the short-period effects. The results showed that the albedo effect on along-track acceleration did not exceed 0.5 pm/s(2), or about 20% of the anomalous acceleration. Even this acceleration showed no correlation in phase with the observed acceleration. The albedo accelerations were also used to calculate the effects on the LAGEOS Keplerian orbital elements. The effects on the LAGEOS node and inclination excitations were significant, having amplitudes of several milliarc seconds (mas) per year. The largest effects were found to be on the eccentricity excitation function, having amplitudes at the 50-100 mas/yr level. The patterns also correlate well with the observed eccentricity vector excitations, but with a difference in sign, suggesting that some parameters estimated with LAGEOS data, such as ocean tide parameters, may have been corrupted by albedo effects. C1 NASA, GODDARD SPACE FLIGHT CTR, GEODYNAM BRANCH, TERR PHYS LAB, GREENBELT, MD 20771 USA. RP Martin, CF (reprint author), EG&G, WASHINGTON ANALYT SERV CTR, 1396 PICCARD DR, ROCKVILLE, MD 20850 USA. RI Rubincam, David/D-2918-2012 NR 26 TC 24 Z9 24 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1996 VL 101 IS B2 BP 3215 EP 3226 DI 10.1029/95JB02810 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV380 UT WOS:A1996TV38000032 ER PT J AU Burbank, DW Leland, J Fielding, E Anderson, RS Brozovic, N Reid, MR Duncan, C AF Burbank, DW Leland, J Fielding, E Anderson, RS Brozovic, N Reid, MR Duncan, C TI Bedrock incision, rock uplift and threshold hillslopes in the northwestern Himalayas SO NATURE LA English DT Article ID COSMOGENIC NUCLIDES; PAKISTAN AB The topography of tectonically active mountain ranges reflects a poorly understood competition between bedrock uplift and erosion. Dating of abandoned river-cut surfaces in the northwestern Himalayas reveals that the Indus river incises through the bedrock at extremely high rates (2-12 mm yr(-1)). in the surrounding mountains, the average angles of hillslopes are steep and essentially independent of erosion rate, suggesting control by a common threshold process. In this rapidly deforming region, an equilibrium is maintained between bedrock uplift and river incision, with landsliding allowing hillslopes to adjust efficiently to rapid river down-cutting. C1 UNIV CALIF LOS ANGELES,DEPT EARTH & SPACE SCI,LOS ANGELES,CA 90095. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF SANTA CRUZ,DEPT EARTH SCI,SANTA CRUZ,CA 95064. UNIV CALIF SANTA CRUZ,INST TECTON,SANTA CRUZ,CA 95064. UNIV CORDOBA,DEPT GEOL SCI,INST STUDY CONTINENTS,ITHACA,NY 14853. RP Burbank, DW (reprint author), UNIV SO CALIF,DEPT EARTH SCI,LOS ANGELES,CA 90089, USA. RI Fielding, Eric/A-1288-2007; OI Fielding, Eric/0000-0002-6648-8067; Brozovic, Nicholas/0000-0002-2218-4934 NR 34 TC 609 Z9 645 U1 8 U2 86 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 8 PY 1996 VL 379 IS 6565 BP 505 EP 510 DI 10.1038/379505a0 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TU693 UT WOS:A1996TU69300040 ER PT J AU Russell, JM Luo, MZ Cicerone, RJ Deaver, LE AF Russell, JM Luo, MZ Cicerone, RJ Deaver, LE TI Satellite confirmation of the dominance of chlorofluorocarbons in the global stratospheric chlorine budget SO NATURE LA English DT Article ID OZONE DEPLETION; CARBON-DIOXIDE; GROWTH-RATES; ATMOSPHERE; HCL; CHLOROFLUOROMETHANES; DESTRUCTION; DECREASE; VORTEX; HF AB OBSERVED increases in concentrations of chlorine in the stratosphere(1-7) have been widely implicated in the depletion of lower-stratospheric ozone over the past two decades(8-14). The present concentration of stratospheric chlorine is more than five times that expected from known natural 'background' emissions from the oceans and biomass burning(15-18), and the balance has been estimated to be dominantly anthropogenic in origin, primarily due to the breakdown products of chlorofluorocarbons (CFCs)(19,20). But despite the wealth of scientific data linking chlorofluorocarbon emissions to the observed chlorine increases, the political sensitivity of the ozone-depletion issue has generated a re-examination of the evidence(21,22). Here we report a four-year global time series of satellite observations of hydrogen chloride (HCl) and hydrogen fluoride (HF) in the stratosphere, which shows conclusively that chlorofluorocarbon releases-rather than other anthropogenic or natural emissions-are responsible for the recent global increases in stratospheric chlorine concentrations. Moreover, all but a few per cent of observed stratospheric chlorine amounts can be accounted for by known natural and anthropogenic tropospheric emissions, Altogether, these results implicate the chlorofluorocarbons beyond reasonable doubt as dominating ozone depletion in the lower stratosphere. C1 UNIV CALIF IRVINE,IRVINE,CA 92717. RP Russell, JM (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 36 TC 65 Z9 68 U1 0 U2 8 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 8 PY 1996 VL 379 IS 6565 BP 526 EP 529 DI 10.1038/379526a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TU693 UT WOS:A1996TU69300045 ER PT J AU Lipa, JA Swanson, DR Nissen, JA Chui, TCP Israelsson, UE AF Lipa, JA Swanson, DR Nissen, JA Chui, TCP Israelsson, UE TI Heat capacity and thermal relaxation of bulk helium very near the lambda point SO PHYSICAL REVIEW LETTERS LA English DT Article ID RENORMALIZATION-GROUP; CRITICAL EXPONENTS; T-LAMBDA; HE-4; UNIVERSALITY; CONDUCTIVITY; TRANSITION; PRESSURE; MODEL AB We report new high-resolution measurements of the heat capacity of liquid helium to within 2 nK from the lambda transition, performed with a large sample in earth orbit. The optimum value for the critical exponent characterizing the divergence of the heat capacity below the transition was found to be -0.01285, giving improved support for the renormalization-group theory of phase transitions. Some information on the temperature dependence of the thermal conductivity just above the transition was also obtained. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Lipa, JA (reprint author), STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305, USA. NR 37 TC 176 Z9 176 U1 2 U2 7 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 FEB 5 PY 1996 VL 76 IS 6 BP 944 EP 947 DI 10.1103/PhysRevLett.76.944 PG 4 WC Physics, Multidisciplinary SC Physics GA TT491 UT WOS:A1996TT49100023 ER PT J AU Bauschlicher, CW AF Bauschlicher, CW TI On the ground state of MnCO- SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ION PHOTOELECTRON-SPECTROSCOPY; TRANSITION-METAL ATOMS; GAUSSIAN-BASIS SETS; MOLECULAR CALCULATIONS; EXPANSIONS; ORBITALS; CI(SD); CUCO AB The ground state of MnCO- is predicted to be (II)-I-5, which is derived from a mixture of the 3d(6)4s(2) and 3d(5)4s(2)4p(1) occupations of Mn-. The (II)-I-7 state, which is derived from the 3d(5)4s(2)4p(1) occupation, is found to be only slightly higher in energy. On the basis of the calculations, the two MnCO states observed in photoelectron detachment experiment are assigned as (II)-I-4 and (II)-I-6. The computed geometries and vibrational frequencies are in reasonable agreement with experiment. RP Bauschlicher, CW (reprint author), NASA,AMES RES CTR,STC-230-3,MOFFETT FIELD,CA 94035, USA. NR 20 TC 8 Z9 8 U1 1 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 FEB 2 PY 1996 VL 249 IS 3-4 BP 244 EP 248 DI 10.1016/0009-2614(95)01380-6 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TV044 UT WOS:A1996TV04400015 ER PT J AU Freeland, RE Bilyeu, GD Veal, GR AF Freeland, RE Bilyeu, GD Veal, GR TI Development of flight hardware for a large, inflatable-deployable antenna experiment SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB Large, space-based antennas are needed for a variety of different applications. Since there is no meaningful orbital assembly capability planned at this time, any large space structures will have to be self-deployable. Current concepts for large, conventional, mechanical, self-deployable space structures tend to be very expensive and mechanically complicated. Current antenna-user requirements are so stringent (with respect to the need for very low-cost, high-deployment reliability, low weight, and packaged-volume and usable aperture precision) that new and innovative approaches to accommodate large space structures are needed. Fortunately, a newly developed class of space structures, called inflatable-deployable structures, has great potential for satisfying these stringent user requirements. A concept under development at L'Garde, Inc., for a large, inflatable-deployable antenna represents an excellent example of this new type of structure. RP Freeland, RE (reprint author), CALTECH,JET PROP LAB,APPL MECH TECHNOL SECT,PASADENA,CA 91125, USA. NR 8 TC 15 Z9 20 U1 1 U2 7 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 FEB-APR PY 1996 VL 38 IS 4-8 BP 251 EP 260 DI 10.1016/0094-5765(96)00030-6 PG 10 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200006 ER PT J AU Hines, JW AF Hines, JW TI Medical and surgical applications of space biosensor technology SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB Researchers in space life sciences are rapidly approaching a technology impasse. Many of the critical questions on the impact of spaceflight on living systems simply cannot be answered with the limited available technologies. Research subjects, particularly small animal models like the rat, must be allowed to function relatively untended and unrestrained for long periods to fully reflect the impact of microgravity and spaceflight on their behavior and physiology. These requirements preclude the use of present hard-wired instrumentation techniques and limited data acquisition systems. Implantable sensors and miniaturized biotelemetry are the only means of capturing the fundamental and critical data. This same biosensor and biotelemetry technology has direct application to Earth-based medicine and surgery. Continuous, on-line data acquisition and improved measurement capabilities combined with the ease and flexibility offered by automated, wireless, and portable instruments and data systems, should provide a boon to the health care industry. Playing a key role in this technology revolution is the Sensors 2000! (S2K!) Program at NASA Ames Research Center. S2K!, in collaboration with space life sciences researchers and managers, provides an integrated capability for sensor technology development and applications, including advanced biosensor technology development, spaceflight hardware development, and technology transfer and commercialization. S2K! is presently collaborating on several spaceflight projects with dual-use medical applications. One prime example is a collaboration with the Fetal Treatment Center (FTC) at the University of California at San Francisco. The goal is to develop and apply implantable chemical sensor and biotelemetry technology to continuously monitor fetal patients during extra-uterine surgery, replacement into the womb, through birth and beyond. Once validated for ground use, the method will be transitioned to spaceflight applications to remotely monitor key biochemical parameters in flight animals. Successful application of NASA implantable biosensor and biotelemetry technologies should accelerate the advancement of this and other modern medical procedures while furthering the exploration of life in space. RP Hines, JW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 4 TC 8 Z9 9 U1 0 U2 5 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 FEB-APR PY 1996 VL 38 IS 4-8 BP 261 EP 267 DI 10.1016/0094-5765(96)00025-2 PG 7 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200007 PM 11541303 ER PT J AU Freeman, DC Talay, TA Austin, RE AF Freeman, DC Talay, TA Austin, RE TI Single-stage-to-orbit - Meeting the challenge SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB There has been and continues to be significant discussion about the viability of fully reusable, single-stage-to-orbit (SSTO) concepts for delivery of payloads to orbit. Often, these discussions have focused in detail on performance and technology requirements relating to the technical feasibility of the concept, with only broad generalizations on how the SSTO will achieve its economic goals of greatly reduced vehicle ground and flight operations costs. With the current industry and NASA Reusable Launch Vehicle Technology Program efforts underway to mature and demonstrate technologies leading to a viable commercial launch system that also satisfies national needs, achieving acceptable recurring costs becomes a significant challenge. This paper reviews the current status of the Reusable Launch Vehicle Technology Program including the DC-XA, X-33, X-34 flight systems and associated technology programs. The paper also examines lessons learned from the recently completed DC-X reusable rocket demonstrator program. It examines how these technologies and flight systems address the technical and operability challenges of SSTO whose solutions are necessary to reduce costs. The paper also discusses the management and operational approaches that address the challenge of a new cost-effective, reusable launch vehicle system. RP Freeman, DC (reprint author), NASA,LANGLEY RES CTR,SPACE SYST & CONCEPTS DIV,HAMPTON,VA 23681, USA. NR 8 TC 4 Z9 4 U1 0 U2 1 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 FEB-APR PY 1996 VL 38 IS 4-8 BP 323 EP 331 DI 10.1016/0094-5765(96)00051-3 PG 9 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200011 ER PT J AU ONeil, WJ Ausman, NE Landano, MR Smith, MA AF ONeil, WJ Ausman, NE Landano, MR Smith, MA TI Galileo on Jupiter approach SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB After six years of interplanetary flight, in just two months, on December 7, 1995, Galileo will arrive at Jupiter. In July, Galileo released its Atmospheric Entry Probe on the five-month solo, ballistic flight to Jupiter entry. After Probe release, the Orbiter fired its 400-N main engine for the first time to deflect the Orbiter to its Io flyby aim point, establishing the trajectory for Probe radio relay link acquisition and orbit insertion. The 400-N engine was specifically used for the deflection in order to check it out prior to orbit insertion. Last February, the Galileo Orbiter Command and Data Subsystem (CDS) and Attitude and Articulation Control Subsystem (AACS) computers were completely re-loaded to provide new software capabilities for main engine and relay link autonomous fault protection and for backup Probe data storage on the Orbiter. The execution and results of this complete inflight software change are discussed. The status of the Entry Probe prior to release is described-once released there is no communication link with the Probe until after entry. The operation and performance of the 400-N main engine at the deflection burn is explained in the context of its required use for orbit insertion. Final predictions for the Probe entry conditions, Probe-to-Orbiter radio relay link, and Orbiter insertion performance are given. Overall mission status and spacecraft health are summarized. RP ONeil, WJ (reprint author), CALTECH,JET PROP LAB,GALILEO PROJECT,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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB-APR PY 1996 VL 38 IS 4-8 BP 349 EP 366 DI 10.1016/0094-5765(96)00037-9 PG 18 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200013 ER PT J AU Cunningham, GE AF Cunningham, GE TI Mars global surveyor mission SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB The development of a new mission to observe Mars from orbit is underway by the National Aeronautics and Space Administration and the Jet Propulsion Laboratory. This mission, the Mars Global Surveyor, will be launched in late 1996, and is the first mission of the new Mars Surveyor Program, a program with international participation, that will characterize the planet Mars from orbital observations and from surface measurements. This paper discusses the technical and programmatic considerations which have been combined to formulate the plans for the Mars Global Surveyor (MGS). The first objective of the mission is to complete, as fully as possible, the five original science objectives of the failed Mars Observer mission, The MGS spacecraft which will accommodate pan of the Mars Observer instrument payload, will focus on surface science to provide the data base for-landed missions that will follow in the Mars Surveyor Program in later years. Secondly, the spacecraft will provide a one-way relay capability for US and international landed and atmospheric missions, Thirdly, the mission will provide special emphasis on those measurements which could impact landing site selection. The performance requirements for the MGS spacecraft will be discussed and the payload will be described. The status of the project development at launch minus 13 months will be highlighted. The implementation of this mission will be affordable, engaging to the public and provide numerous public educational benefits. Its management will be cost, rather than performance, driven. Low cost mission operations will be incorporated. The programmatic approach and plans will be described. Finally, lessons learned from the Mars Observer experience will be shown to provide enhancements to the affordability and success of the Mars Global Surveyor Mission. RP Cunningham, GE (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 1 Z9 1 U1 0 U2 6 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 FEB-APR PY 1996 VL 38 IS 4-8 BP 367 EP 375 DI 10.1016/0094-5765(96)00035-5 PG 9 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200014 ER PT J AU Potter, A Mulrooney, M AF Potter, A Mulrooney, M TI Liquid metal mirror for optical measurements of orbital debris SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB A telescope employing a liquid metal mirror that is three meters in diameter has been developed for the purpose of measuring the population of small orbital debris. The telescope has been installed at a location in the mountains of New Mexico, and is undergoing final engineering tests. The limiting stellar magnitude of the telescope has been measured to be 21.5, with resolution of 1.8 arcsec. The highest sensitivity for orbital debris detection is achieved by reading out the CCD detector at the same rats and in the same direction as the debris object crosses the field of view of the telescope. In this mode, the telescope is capable of detecting debris as small as 2.5 centimeters at 900 km altitude, and less than 10 centimeters at geosynchronous altitudes. Improved performance for LEO altitudes might be achieved by the use of fast readout detectors. RP Potter, A (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE SCI BRANCH,HOUSTON,TX 77058, USA. NR 7 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 FEB-APR PY 1996 VL 38 IS 4-8 BP 423 EP 425 DI 10.1016/0094-5765(96)00058-6 PG 3 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200020 ER PT J AU Roberts, RR Milov, YG Zonov, YV Salikhov, RS Charles, LB AF Roberts, RR Milov, YG Zonov, YV Salikhov, RS Charles, LB TI IAN-USA SAGE III/Meteor-3M project. SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 46th International-Astronautical-Federation Congress CY OCT 02-06, 1995 CL OSLO, NORWAY SP Int Astronaut Federat AB The Russian Space Agency of the Russian Federation and the National Aeronautics and Space Administration of the United States have agreed to fly a US Stratospheric Aerosol and Gas Experiment (SAGE III) instrument aboard a Russian Meteor-3M spacecraft in 1998 and a US Total Ozone Mapping Spectrometer (TOMS) in 2000. These joint projects are part of the Russia-US Mission to Planet Earth Joint Working Group under the Gore Chernomyrdin Commission, and continue the successful Russian-American cooperation in atmospheric chemistry and physics. This paper describes the organization of the these projects, outlines the development plans for the instrument, and provides technical descriptions of the Meteor-3M/SAGE III mission. RP Roberts, RR (reprint author), NASA,WASHINGTON,DC 20546, 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB-APR PY 1996 VL 38 IS 4-8 BP 479 EP 485 DI 10.1016/0094-5765(96)00020-3 PG 7 WC Engineering, Aerospace SC Engineering GA VJ682 UT WOS:A1996VJ68200026 ER PT J AU Schertler, RJ Gedney, RT Zernic, MJ AF Schertler, RJ Gedney, RT Zernic, MJ TI ACTS' legacy: The Ka-band explosion SO AEROSPACE AMERICA LA English DT Article RP Schertler, RJ (reprint author), NASA,LEWIS RES CTR,ACTS EXPT OFF,CLEVELAND,OH 44135, 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 FEB PY 1996 VL 34 IS 2 BP 33 EP 36 PG 4 WC Engineering, Aerospace SC Engineering GA TV325 UT WOS:A1996TV32500010 ER PT J AU Escher, WJD AF Escher, WJD TI A winning combination for tomorrow's spaceliners SO AEROSPACE AMERICA LA English DT Article RP Escher, WJD (reprint author), NASA HEADQUARTERS,ADV SPACE TRANSPORTAT TECHNOL,WASHINGTON,DC 20546, 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 FEB PY 1996 VL 34 IS 2 BP 38 EP 43 PG 6 WC Engineering, Aerospace SC Engineering GA TV325 UT WOS:A1996TV32500011 ER PT J AU Katz, J Yon, S Rogers, SE AF Katz, J Yon, S Rogers, SE TI Impulsive start of a symmetric airfoil at high angle of attack SO AIAA JOURNAL LA English DT Article ID UPWIND DIFFERENCING SCHEME; NAVIER-STOKES EQUATIONS; LIFT; FLOW AB The fluid dynamic phenomena following the impulsive start of a NACA 0015 airfoil were studied by using a time accurate solution of the incompressible, laminar Navier-Stokes equations. Angle of attack was set at 10 deg to simulate steady-state poststall conditions at a Reynolds number of 1.2 x 10(4). The calculation revealed that large initial lift values can be obtained, immediately following the impulsive start, when a trapped vortex develops above the airfoil. Before the buildup of this trapped vortex and immediately after the airfoil was set into motion, the fluid is attached to the airfoil's surface and flows around the trailing edge, demonstrating the delay In the buildup of the classical Kutta condition. The transient of this effect is quite short and Is followed by an attached flow event that leads to the trapped vortex that has a longer duration. The just described initial phenomenon eventually transits into a fully developed separated flow pattern identifiable by an alternating, periodic vortex shedding. C1 NASA,AMES RES CTR,DESIGN CYCLE TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP Katz, J (reprint author), SAN DIEGO STATE UNIV,DEPT AEROSP ENGN & ENGN MECH,SAN DIEGO,CA 92182, USA. NR 27 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 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1996 VL 34 IS 2 BP 225 EP 230 DI 10.2514/3.13054 PG 6 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700002 ER PT J AU Mateer, GG Monson, DJ Menter, FR AF Mateer, GG Monson, DJ Menter, FR TI Skin-friction measurements and calculations on a lifting airfoil SO AIAA JOURNAL LA English DT Article AB A new technique for measuring skin friction was employed to help document the Bow on an airfoil at angles of attack from -0.5 to 11.5 deg. Surface pressures were also measured on both the wing and wind-tunnel walls. The experiment was conducted at a freestream Mach number of 0.2 and Reynolds numbers of 0.6, 2, and 6 x 10(6). The objective of the study was to provide data and boundary condition information sufficient for the validation of numerical simulations. Such a simulation of the experiment was conducted using the INS2D Navier-Stokes code with the shear-stress-transport turbulence model. The computations provide a good description of both laminar and turbulent shear levels, except for turbulent Bow on the top surface of the wing at the higher angles of attack. C1 ELORET INST,SUNNYVALE,CA 94035. RP Mateer, GG (reprint author), NASA,AMES RES CTR,AERONAUT TECHNOL DIV,TURBULENCE PHYS & MODELING BRANCH,M-S 229-1,MOFFETT FIELD,CA 94035, USA. NR 15 TC 15 Z9 15 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 FEB PY 1996 VL 34 IS 2 BP 231 EP 236 DI 10.2514/3.13055 PG 6 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700003 ER PT J AU Casper, J Meadows, KR AF Casper, J Meadows, KR TI Using high-order accurate essentially nonoscillatory schemes for aeroacoustic applications SO AIAA JOURNAL LA English DT Article AB The numerical study of aeroacoustic problems places stringent demands on the choice of a computational algorithm, particularly when shock waves are involved, Because of their dual capacity for high-order accuracy and high-resolution shock capturing, the recently developed class of essentially nonoscillatory (ENO) schemes has generated considerable interest in regard to such problems. The use of ENO schemes for aeroacoustic applications is investigated, with particular attention to the control of the adaptive stenciling procedure. A modification of previously developed stencil-biasing procedures is proposed. This nonlinear stencil biasing allows a freer adaptation near discontinuities than is allowed by the previous biasing methods, without disturbing the biased, stable stencils that are desired in smooth regions. The accuracy of these new methods is validated through the study of a shocked nozzle flow. An axisymmetric shock-vortex interaction is then investigated, Numerical results indicate a reduction in error when compared with results in which other stencil-biasing procedures are used. C1 VIGYAN INC,ADV TECHNOL GRP,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,DIV FLUID MECH & ACOUST,HAMPTON,VA 23681. NR 11 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 FEB PY 1996 VL 34 IS 2 BP 244 EP 250 DI 10.2514/3.13057 PG 7 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700005 ER PT J AU Maestrello, L AF Maestrello, L TI Control of panel response to turbulent boundary-layer and acoustic excitations SO AIAA JOURNAL LA English DT Article ID CHAOS; TRANSITION AB Nonlinear response of a panel structure results when forced by a subsonic turbulent boundary layer and pure-tone sound in a wind tunnel, It is a coupled problem, where flow, structure, and sound interact, The structure exhibits a broadband response typical of turbulent boundary-layer loading with superimposed pure tone and harmonics over the band, a process which is statistically stationary, but non-Gaussian. The mechanism is an energy transfer process: the amount of energy supplied to the harmonics is removed from the low-frequency band and the fundamental tone, The objective is to control the nonlinear wave using a time-harmonic actuator tone, Full control is almost achieved using a single controller, Two steps are taken: first, control the harmonics by feeding the energy back into the fundamental and low-frequency band, and second, control the fundamental tone to shift the energy further back into the low-frequency band, Consequently, the response of the panel Is reduced to the broadband level of the turbulent boundary-layer excitation, a reduction in peak amplitude power level by 20 dB or more, The experiments are motivated by considerations for aircraft interior noise and structural response. RP Maestrello, L (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH & ACOUST,STRUCT ACOUST BRANCH,MAIL STOP 463,HAMPTON,VA 23681, USA. NR 36 TC 3 Z9 3 U1 0 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 FEB PY 1996 VL 34 IS 2 BP 259 EP 264 DI 10.2514/3.13059 PG 6 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700007 ER PT J AU Lyrintzis, AS Mankbadi, RR AF Lyrintzis, AS Mankbadi, RR TI Prediction of the far-field jet noise using Kirchhoff's formulation SO AIAA JOURNAL LA English DT Article C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Lyrintzis, AS (reprint author), PURDUE UNIV,W LAFAYETTE,IN 47907, USA. NR 14 TC 16 Z9 16 U1 0 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 FEB PY 1996 VL 34 IS 2 BP 413 EP 416 DI 10.2514/3.13079 PG 4 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700027 ER PT J AU Decker, AJ Buggele, AE AF Decker, AJ Buggele, AE TI Automation of some operations of a wind tunnel using artificial neural networks SO AIAA JOURNAL LA English DT Article C1 NASA,LEWIS RES CTR,AEROPROP FACILITIES & EXPT DIV,CLEVELAND,OH 44135. RP Decker, AJ (reprint author), NASA,LEWIS RES CTR,INSTRUMENTAT & CONTROL TECHNOL DIV,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 7 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 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1996 VL 34 IS 2 BP 421 EP 423 DI 10.2514/3.13082 PG 3 WC Engineering, Aerospace SC Engineering GA TT877 UT WOS:A1996TT87700030 ER PT J AU Hay, SI Tucker, CJ Rogers, DJ Packer, MJ AF Hay, SI Tucker, CJ Rogers, DJ Packer, MJ TI Remotely sensed surrogates of meteorological data for the study of the distribution and abundance of arthropod vectors of disease SO ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY LA English DT Review ID HIGH-RESOLUTION RADIOMETER; SATELLITE DATA; VEGETATION INDEX; SURFACE TEMPERATURES; AVHRR DATA; RAINFALL; IDENTIFICATION; LIMITATIONS; REFLECTANCE; IMAGERY AB This paper gives an overview of how certain meteorological data used in studies of the population dynamics of arthropod vectors of disease may be predicted using remotely sensed, satellite data. Details are given of the stages of processing necessary to convert digital data arising from satellite sensors into ecologically meaningful information. Potential sources of error in these processing steps are also highlighted. Relationships between ground-measured meteorological variables (saturation deficit, ground temperature and rainfall) and data from both the National Oceanic and Atmospheric Administration's, polar-orbiting, meteorological satellites and the geostationary, Meteosat satellite are defined and examples detailed for Africa. Finally, the current status of existing satellite platforms and future satellite missions are reviewed and potential data availability discussed. How such satellite-based predictions have proved valuable in understanding the distribution of tsetse fly species in Cote d'Ivoire and Burkina Faso will be the subject of a future review. C1 NASA,GODDARD SPACE FLIGHT CTR,EARTH RESOURCE BRANCH,GREENBELT,MD 20771. RP Hay, SI (reprint author), UNIV OXFORD,DEPT ZOOL,TRYPANOSOMIASIS & LAND USE AFRICA RES GRP,S PARKS RD,OXFORD OX1 3PS,ENGLAND. RI Hay, Simon/F-8967-2015 OI Hay, Simon/0000-0002-0611-7272 NR 90 TC 108 Z9 121 U1 0 U2 3 PU W B SAUNDERS CO LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0003-4983 J9 ANN TROP MED PARASIT JI Ann. Trop. Med. Parasitol. PD FEB PY 1996 VL 90 IS 1 BP 1 EP 19 PG 19 WC Public, Environmental & Occupational Health; Parasitology; Tropical Medicine SC Public, Environmental & Occupational Health; Parasitology; Tropical Medicine GA TU809 UT WOS:A1996TU80900001 PM 8729623 ER PT J AU Trolinger, JD Lal, RB McIntosh, D Witherow, WK AF Trolinger, JD Lal, RB McIntosh, D Witherow, WK TI Holographic particle image velocimetry in the first International Microgravity Laboratory aboard the Space Shuttle Discovery SO APPLIED OPTICS LA English DT Article DE particle-image velocimetry; holography; microgravity ID FLOW AB In January 1992 the Space Shuttle Discovery carried the first International Microgravity Laboratory into Earth orbit for eight days. One of the many experiments carried out during the orbit was a combined study of triglycine sulfate crystal growth from solution and fluid-particle-dynamics studies in microgravity. Optical diagnostics included holocameras to provide concentration measurements and three-dimensional particle tracking. More than 1000 holograms that were recorded in space have been analyzed since the flight, providing a wide range of interesting conclusions about microgravity, crystal growth, and particle dynamics. This paper focuses on the results of holographic particle-image velocimetry experiments and provides an excellent example, along with new techniques, for exploiting holography for particle and flow diagnostics. (C) 1996 Optical Society of America C1 ALABAMA A&M UNIV,DEPT PHYS,NORMAL,AL 35762. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP Trolinger, JD (reprint author), METROLASER,18006 SKYPART CIRCLE 108,IRVINE,CA 92714, USA. NR 18 TC 25 Z9 26 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 1 PY 1996 VL 35 IS 4 BP 681 EP 689 DI 10.1364/AO.35.000681 PG 9 WC Optics SC Optics GA TU776 UT WOS:A1996TU77600017 PM 21069056 ER PT J AU Tingay, SJ Jauncey, DL Reynolds, JE Tzioumis, AK Migenes, V Gough, R Lovell, JEJ McCulloch, P Costa, ME Preston, RA Harrison, P AF Tingay, SJ Jauncey, DL Reynolds, JE Tzioumis, AK Migenes, V Gough, R Lovell, JEJ McCulloch, P Costa, ME Preston, RA Harrison, P TI Parsec-scale morphology of PKS 2152-699 and the radio optical misalignment SO ASTRONOMICAL JOURNAL LA English DT Article ID EMISSION; GAS AB We present the first very-long-baseline interferometry (VLBI) image of the parsec-scale structure in the nearby (z=0.0282) Fanaroff-Riley type II radio galaxy PKS 2152-699, revealing the core-jet morphology typical of compact radio sources. Tadhunter ct al. [MNRAS, 235, 403 (1988)] have identified this object as one in which the radio axis and optical emission line features on the kiloparsec-scale appear to have an obvious connection but are somewhat misaligned, They interpret this relationship as most likely being due to an interaction between the radio jet and an extra-nuclear cloud of gas, the misalignment possibly caused by the deflection of the radio jet in the interaction. The VLBI observations presented here further strengthen the evidence for the interaction interpretation. The parsec-scale radio jet aligns strongly with optical emission line features, and not with the kiloparsec-scale radio structure. We explore a mechanism which could produce the misalignment and which is consistent with the interaction concept, namely oblique shocks in a relativistic jet. With a minimal model we find that reasonable values of the model parameters can provide the required misalignment over a wide range of initial conditions. (C) 1996 American Astronomical Society. C1 AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. UNIV TASMANIA,HOBART,TAS 7001,AUSTRALIA. UNIV WESTERN AUSTRALIA,PERTH,WA 6009,AUSTRALIA. CALTECH,JET PROP LAB,PASADENA,CA 91109. BRITISH AEROSP PLC,CANBERRA,ACT 2601,AUSTRALIA. RP Tingay, SJ (reprint author), MT STROMLO & SIDING SPRING OBSERV,CANBERRA,ACT 2611,AUSTRALIA. RI Tingay, Steven/B-5271-2013; Migenes, Victor/F-3157-2015 OI Migenes, Victor/0000-0002-7990-2191 NR 19 TC 12 Z9 12 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 FEB PY 1996 VL 111 IS 2 BP 718 EP 721 DI 10.1086/117818 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT552 UT WOS:A1996TT55200010 ER PT J AU Austin, SJ Wagner, RM Starrfield, S Shore, SN Sonneborn, G Bertram, R AF Austin, SJ Wagner, RM Starrfield, S Shore, SN Sonneborn, G Bertram, R TI V1974 Cygni 1992: Optical and ultraviolet evolution and analysis SO ASTRONOMICAL JOURNAL LA English DT Article ID HEAVY ELEMENT ABUNDANCES; NOVA-AQUILAE 1982; SPECTRAL EVOLUTION; SPECTROSCOPIC OBSERVATIONS; OPTIMAL EXTRACTION; CLASSICAL NOVAE; VULPECULAE; OUTBURST; RECOMBINATION; NOVA-CYGNI-1992 AB We have obtained optical spectrophotometry of V1974 Cygni (Nova Cygni 1992), the brightest nova since 1975, from day 4 to 540 after visual maximum, which we have combined with ultraviolet spectrophotometry to study the ejecta, We show high quality ultraviolet and optical spectra at each major evolutionary phase, identify the lines present during the nebular phase, and show the temporal development of the emission line fluxes and widths. The optical spectral evolution of this nova, using the CTIO system, was P(Fe,N)A(Ne). V1974 Cygni is classified as a ''neon nova'' since [Ne III] lambda 3869 and [Ne V] lambda 3425 were the strongest emission lines during the nebular phase. We determined the physical conditions and elemental abundances of the ejecta during the optically thin phase. Because the densities were high and the shell was not spatially resolved we have developed a completely new method which involves the combination of photoionization models and a multiparameter Monte Carlo fitting of the relative emission-line fluxes, The line spectra from days 300, 400, and 500 were modeled, and the inhomogeneity of the ejected material was simulated by considering large variations in the filling and covering factors, as well as letting the density vary as a function of radius. Enhancements above solar were found for He, N, O, Ne, and Fe with abundances by (number relative to solar and with 90% confidence uncertainties) of N(He)/N-H=4.4(-3)(+9), N(N)/N-H=282(-192)(+117), N(O)/N-H=110(-67)(+43), N(Ne)/N-H=250(-159)(+150), and N(Fe)/N-H=16(-12)(+28). The large neon abundance can only be explained by the ejection of core material from an ONeMg white dwarf. The resulting helium abundance places the ejected mass at about 5X10(-5) M(.). This ejected mass and x-ray studies were used to estimate that the mass of the white dwarf is about 1.3 M(.). Line profiles of Balmer, nebular, and coronal lines, obtained in high resolution during the nebular phase, exhibit nearly identical multicomponent, symmetric sawtooth shapes, indicating the same gas morphology over a wide range of ionization. (C) 1996 American Astronomical Society. C1 OHIO STATE UNIV, DEPT ASTRON, COLUMBUS, OH 43210 USA. INDIANA UNIV, DEPT PHYS & ASTRON, S BEND, IN 46634 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP Austin, SJ (reprint author), ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. RI Sonneborn, George/D-5255-2012 NR 87 TC 55 Z9 55 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 1996 VL 111 IS 2 BP 869 EP 898 DI 10.1086/117835 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT552 UT WOS:A1996TT55200027 ER PT J AU Cohen, M Hitchon, K AF Cohen, M Hitchon, K TI Studies of extreme carbon stars .2. Periods from optical spectral characteristics SO ASTRONOMICAL JOURNAL LA English DT Article ID SHOCK-WAVE INTERPRETATION; MIRA VARIABLES; IRC +10216; EMISSION-LINES AB We present a simple analysis of the time variations of several optical spectral characteristics for a sample of optically very faint, infrared-selected, extreme carbon stars. This analysis yields estimates of stellar periods that show these dust-embedded stars to be long-period (similar to 1.5 yr) Mira variables. We have not found any ECS analogous to the extremely long-period OH/IR stars: the longest ECS period is similar to 2 yr. We explore the relationships between amplitude of variation of H alpha emission and its mean level, and discuss the likelihood that some ECS dust shells are disklike rather than spherical. We investigate the relative phasing of the cycles of H alpha, sodium absorption, optical continuum colors, and infrared photometric variations. The combination of optical, near-infrared and IRAS photometry permits estimates to be made of both stellar distance and circumstellar extinction, through the bolometric luminosity. (C) 1996 American Astronomical Society. C1 NASA,AMES RES CTR,DIV SPACE SCI,INT SUMMER STUDENT PROGRAM,MOFFETT FIELD,CA 94035. UNIV CALIF SANTA CRUZ,LICK OBSERV,SANTA CRUZ,CA 95064. RP Cohen, M (reprint author), UNIV CALIF BERKELEY,RADIO ASTRON LAB,BERKELEY,CA 94720, USA. NR 41 TC 16 Z9 17 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 FEB PY 1996 VL 111 IS 2 BP 962 EP 969 DI 10.1086/117843 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT552 UT WOS:A1996TT55200035 ER PT J AU deKoter, A Lamers, HJGLM Schmutz, W AF deKoter, A Lamers, HJGLM Schmutz, W TI Variability of luminous blue variables .2. Parameter study of the typical LBV variations SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars, atmospheres; stars, early-type; stars, mass-loss; radiative transfer ID RADIATION-DRIVEN WINDS; LARGE MAGELLANIC CLOUD; MASS-LOSS; S-DOR; STARS; MODELS; LMC AB We present predicted photometric and spectroscopic variations for Luminous Blue Variables (LBVs) based on a computed grid of Non-LTE extended and expanding atmosphere models. The effects of (i) mass loss, (ii) terminal dow velocity, (iii) rate of acceleration of the flow, (iv) minimum wind temperature, (v) effective gravity, and (vi) underlying stellar radius are investigated. We show that the characteristic variations in visual magnitude for LBVs of Delta V similar or equal to 1 to 2 mag, which occur at constant luminosity and are therefore associated with a change in photospheric radius and temperature, cannot be due to the formation of a 'pseudo' photosphere in the wind induced by a dramatic increase in mass loss rate. This implies that the origin of the mechanism responsible for the variations is located below the atmosphere. The change in photospheric radius that can be achieved by changing the wind parameters (i) to (iv), using observed mass loss rates, is similar to 40%. However, a change of a factor of 4 to 12, depending on luminosity, is needed to reach the observed minimum effective temperature of LBVs of T-eff approximate to 8000 K. We conclude that the observed increase in photospheric radius is due to the combined effect of an increase in the underlying stellar radius (vi) and a reduced effective gravity (v). Our calculations further show that mass loss and velocity structure variations may in principle cause visual magnitude changes of Delta V less than or similar to 0.2m, however only if the optical depth of the wind is at the outset of the order of unity. To estimate the optical depth of the wind, we provide a simple formula. We also show the sensitivity of the profiles of several H and He I lines to changes in the photospheric and wind parameters and explain the behaviour of Ha in simple physical terms. C1 SRON, LAB SPACE RES, 3584 CA UTRECHT, NETHERLANDS. INST ASTRON, 3584 CC UTRECHT, NETHERLANDS. INST ASTROPHYS, CH-8092 ZURICH, SWITZERLAND. RP deKoter, A (reprint author), UNIV SPACE RES ASSOC, GODDARD SPACE FLIGHT CTR, CODE 681, GREENBELT, MD 20771 USA. RI Schmutz, Werner/B-4153-2014 OI Schmutz, Werner/0000-0003-1159-5639 NR 35 TC 47 Z9 47 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 FEB PY 1996 VL 306 IS 2 BP 501 EP 518 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TV547 UT WOS:A1996TV54700021 ER PT J AU Warin, S Castets, A Langer, WD Wilson, RW Pagani, L AF Warin, S Castets, A Langer, WD Wilson, RW Pagani, L TI The structure and dynamics of NGC 1333 from (CO)-C-13 and (CO)-O-18 observations SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE star, formation; ISM, clouds; ISM, molecules; ISM, kinematics and dynamics; ISM, individual objects, NGC 1333; radio lines, ISM ID HERBIG-HARO OBJECTS; VELOCITY MOLECULAR GAS; CARBON-MONOXIDE; DARK CLOUDS; VISUAL EXTINCTION; NGC-1333; EMISSION; PERSEUS; OUTFLOW; CO AB This paper presents a study of a dense molecular region, NGC 1333, and the relationship of the embedded infrared sources and young stellar objects to the structure of its molecular core, We use (CO)-C-13 and (CO)-O-18 J=1-->0 and J=2-->1 observations, along with those of CS J=2-->1 to characterize the structure of the core, calculate densities and masses. We find from our (CO)-O-18 maps that the core consists of a cavity surrounded by a compressed shell of gas. Many of the infrared and outflow sources in NGC 1333 are located in the cavity. The winds from IRAS2, SSV13 and several other sources appear to provide the energy to sweep up the material, expand the cavity and compress the shell. We suggest that sequential star formation is taking place in NGC 1333 with SSV13 initiating this scenario. Several massive (similar to 20-40 M.) condensations in the shell are potential sites for the next generation of star formation in NGC 1333. C1 JET PROPULS LAB, PASADENA, CA 91109 USA. AT&T BELL LABS, HOLMDEL, NJ 07733 USA. OBSERV PARIS, DEMIRM, F-75014 PARIS, FRANCE. RP Warin, S (reprint author), OBSERV GRENOBLE, ASTROPHYS LAB, BP 53X, F-38041 GRENOBLE 9, FRANCE. OI Wilson, Robert/0000-0001-5694-6725 NR 46 TC 54 Z9 56 U1 0 U2 3 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 FEB PY 1996 VL 306 IS 3 BP 935 EP 946 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TW742 UT WOS:A1996TW74200030 ER PT J AU Francis, PJ Woodgate, BE Warren, SJ Moller, P Mazzolini, M Bunker, AJ Lowenthal, JD Williams, TB Minezaki, T Kobayashi, Y Yoshii, Y AF Francis, PJ Woodgate, BE Warren, SJ Moller, P Mazzolini, M Bunker, AJ Lowenthal, JD Williams, TB Minezaki, T Kobayashi, Y Yoshii, Y TI A group of galaxies at redshift 2.38 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, individual (2139-4434); galaxies, distances and redshifts ID LYMAN-ALPHA SYSTEMS; PRIMEVAL GALAXIES; RADIO GALAXIES; DISK GALAXIES; QSO SPECTRA; EVOLUTION; DISCOVERY; CLUSTERS; SEARCH; EMISSION AB We report the discovery of a group of galaxies at redshift 2.38. We imaged similar to 10% of a claimed supercluster of QSO absorption lines at z = 2.38. In this small field (2' radius), we detect two Ly alpha-emitting galaxies. The discovery of two such galaxies in our tiny held supports Francis & Hewett's interpretation of the absorption-line supercluster as a high-redshift Great Wall. One of the Ly alpha galaxies lies 22 '' from a background QSO and may be associated with a multicomponent Ly alpha absorption complex seen in the QSO spectrum. This galaxy has an extended (similar to 50 kpc), lumpy Ly alpha morphology surrounding a compact, IR-bright nucleus. The nucleus shows a pronounced break in its optical-UV colors at similar to 4000 Angstrom (rest frame), consistent with a stellar population of mass similar to 7 x 10(11) M., an age of greater than 500 Myr, and little ongoing star formation. C IV emission is detected, which suggests that a concealed active galactic nucleus is present. The Ly alpha emission is redshifted by similar to 490 km s(-1) with respect to the C IV emission, probably because of absorption. Extended H alpha emission is also detected; the ratio of Ly alpha flux to H alpha is abnormally low (similar to 0.7), probable evidence for extended dust. This galaxy is surrounded by a number of very red (B - K > 5 mag) objects, some of which have colors that suggest that they too are at z = 2.38. We hypothesize that this galaxy, its neighbors, and a surrounding lumpy gas cloud may be a giant elliptical galaxy in the process of bottom-up formation. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,ASTROPHYS GRP,LONDON SW7 2BZ,ENGLAND. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. UNIV OXFORD,DEPT PHYS,OXFORD OX1 3RH,ENGLAND. LICK OBSERV,SANTA CRUZ,CA 95064. RUTGERS STATE UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08855. UNIV TOKYO,FAC SCI,DEPT ASTRON,BUNKYO KU,TOKYO 113,JAPAN. NATL ASTRON OBSERV,MITAKA,TOKYO 181,JAPAN. UNIV TOKYO,INST ASTRON,MITAKA,TOKYO 181,JAPAN. RES CTR EARLY UNIV,SCH SCI,BUNKYO KU,TOKYO 113,JAPAN. RP Francis, PJ (reprint author), UNIV MELBOURNE,SCH PHYS,PARKVILLE,VIC 3052,AUSTRALIA. RI Woodgate, Bruce/D-2970-2012 NR 53 TC 91 Z9 91 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 FEB 1 PY 1996 VL 457 IS 2 BP 490 EP 499 DI 10.1086/176747 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600003 ER PT J AU Bietenholz, MF Bartel, N Rupen, MP Conway, JE Beasley, AJ Sramek, RA Romney, JD Titus, MA Graham, DA Altunin, VI Jones, DL Rius, A Venturi, T Umana, G Weiler, KW VanDyk, SD Panagia, N Cannon, WH Popelar, J Davis, RJ AF Bietenholz, MF Bartel, N Rupen, MP Conway, JE Beasley, AJ Sramek, RA Romney, JD Titus, MA Graham, DA Altunin, VI Jones, DL Rius, A Venturi, T Umana, G Weiler, KW VanDyk, SD Panagia, N Cannon, WH Popelar, J Davis, RJ TI VLBI observations of the ultracompact radio nucleus of the galaxy M81 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (M81); galaxies, nuclei; radio continuum, galaxies; techniques, interferometric ID ACTIVE GALACTIC NUCLEI; STARBURST; EMISSION AB VLBI observations of the nuclear region of the nearby spiral galaxy M81 reveal the smallest size yet for its core and that of any other extragalactic nucleus: 0.18 mas x 0.07 mas (700 AU x 300 AU) at 22.2 GHz. Images show no brightness structure outside the core region above the sensitivity limit of similar to 2% of the peak brightness. The core is slightly asymmetric with its brightness falling off along its major axis toward the northeast. There has been no significant change in the size and orientation since the last VLBI observation of this source in 1981, giving a nominal expansion velocity of -60 +/- 60 km s(-1). The size varies with observing frequency, with the length of the major axis being proportional to nu(-0.8). The apparent position angle is also frequency dependent, and changes by 35 degrees between 22.2 and 2.3 GHz, equivalent to such a change on a length scale from 700 to 4000 AU. These observations exclude a starburst or supernova origin of the core emission and instead argue for the core being an active galactic nucleus, perhaps with a bent jet, and with properties lying between those of Sgr A* and the cores of powerful radio galaxies and quasars. C1 NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801. HAYSTACK OBSERV,WESTFORD,MA 01886. MAX PLANCK INST RADIOASTRON,D-53121 BONN,GERMANY. CALTECH,JET PROP LAB,PASADENA,CA 91109. CSIC,CTR ESTUD AVANZADOS,E-17300 BARCELONA,SPAIN. INTA,LAB ASTROFIS ESPACIAL & FIS FUNDAMENTAL,E-28080 MADRID,SPAIN. CNR,IST RADIOASTRON,I-40129 BOLOGNA,ITALY. CNR,IST RADIOASTRON,I-96017 NOTO,ITALY. USN,RES LAB,WASHINGTON,DC 20375. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. INST SPACE & TERR SCI,N YORK,ON M3J 3K1,CANADA. NAT RESOURCES CANADA,OTTAWA,ON K1A 0Y3,CANADA. NUFFIELD RADIO ASTRON OBSERV LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. RP Bietenholz, MF (reprint author), YORK UNIV,DEPT PHYS & ASTRON,N YORK,ON M3J 1P3,CANADA. RI Antonio, Rius/A-4873-2012; OI Antonio, Rius/0000-0002-5947-2649; Venturi, Tiziana/0000-0002-8476-6307 NR 34 TC 41 Z9 41 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 FEB 1 PY 1996 VL 457 IS 2 BP 604 EP 609 DI 10.1086/176756 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600012 ER PT J AU Evans, AS Sanders, DB Mazzarella, JM Solomon, PM Downes, D Kramer, C Radford, SJE AF Evans, AS Sanders, DB Mazzarella, JM Solomon, PM Downes, D Kramer, C Radford, SJE TI A search for CO emission in high-redshift powerful radio galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, ISM; infrared, galaxies; radio lines, galaxies ID MOLECULAR GAS; IRAS F10214+4724; OPTICAL MORPHOLOGIES; INFRARED GALAXIES; SPECTROSCOPY; DISCOVERY; HYDROGEN; MERGERS; 3C-368 AB Upper limits for the molecular gas mass of 11 high-redshift (1 < z < 4) powerful radio galaxies (HzPRGs) are presented. These observations include some of the most sensitive extragalactic CO observations to date. The four best-studied radio galaxies (3C 368, 4C 23.56, B2 0902+34, and 4C 41.17) have less than one-third the CO luminosity of the hyperluminous infrared galaxy IRAS F10214+4724, and, assuming a Galactic CO-to-H-2 ratio, they have molecular gas masses comparable to or less than the most gas-rich ultraluminous infrared galaxies (ULIGs) in the local (z less than or equal to 0.3) universe [i.e., M(H-2) < 2-3 x 10(10) h(-2) M.; H-0 = 100 h km s(-1) Mpc(-1) and q(0) = 0.5]. Spectral energy distributions of eight HzPRGs show them to have UV-to-optical luminosities ranging from a factor of similar to 0.1 to 1.0 that of the UV-to-optical luminosity of F10214+4724. Recent submillimeter observations of three HzPRGs suggest that one source, 4C 41.17, may have an intense submillimeter-to-far-infrared excess. However, IRAS observations suggest that HzPRGs as a class are not hyperluminous at far-infrared wavelengths. We also consider how the possibility that F10214+4724 is a gravitationally lensed galaxy affects our interpretation of the data, as well as what it may mean for gas-rich galaxies in general. C1 CALTECH, JET PROP LAB, IPAC, PASADENA, CA 91125 USA. SUNY STONY BROOK, ASTRON PROGRAM, STONY BROOK, NY 11794 USA. INST RADIO ASTRON MILLIMETR, F-38406 ST MARTIN DHERES, FRANCE. INST RADIO ASTRON MILLIMETR, E-18012 GRANADA, SPAIN. NATL RADIO ASTRON OBSERV, TUCSON, AZ 85721 USA. RP Evans, AS (reprint author), UNIV HAWAII, INST ASTRON, 2680 WOODLAWN DR, HONOLULU, HI 96822 USA. OI radford, simon/0000-0001-9113-1660 NR 60 TC 43 Z9 43 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1996 VL 457 IS 2 BP 658 EP 670 DI 10.1086/176761 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600017 ER PT J AU Dixon, DD Bhattacharya, D ONeill, TJ Tumer, OT White, RS Zych, AD Wheaton, WA AF Dixon, DD Bhattacharya, D ONeill, TJ Tumer, OT White, RS Zych, AD Wheaton, WA TI Constrained linear algebraic deconvolution of Poisson data SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods, analytical; methods, data analysis; methods, statistical AB A new method is demonstrated for the deconvolution of Poisson data from an associated linear instrument response. Building on the Wheaten et al. method of direct linear algebraic deconvolution (DLAD), the technique is extended by including the additional physical constraint that the deconvolved source fluxes be nonnegative. This constraint stabilizes the solution against fluctuations that appear as a result of noisy data and greatly lowers the variances in the computed fluxes. The uncertainties in the deconvolved fluxes are directly computable. The algorithm is demonstrated for deconvolution of Compton double-scatter gamma-ray telescope data. C1 CALTECH,JET PROPULS LAB,HIGH ENERGY ASTROPHYS LAB,PASADENA,CA 91109. RP Dixon, DD (reprint author), UNIV CALIF RIVERSIDE,INST GEOPHYS & PLANETARY PHYS,RIVERSIDE,CA 92521, USA. NR 12 TC 4 Z9 4 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 FEB 1 PY 1996 VL 457 IS 2 BP 789 EP 797 DI 10.1086/176773 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600029 ER PT J AU Molteni, D Sponholz, H Chakrabarti, SK AF Molteni, D Sponholz, H Chakrabarti, SK TI Resonance oscillation of radiative shock waves in accretion disks around compact objects SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; hydrodynamics; methods, numerical; shock waves; stars, oscillations ID SMOOTHED PARTICLE HYDRODYNAMICS; TIME-DEPENDENT ACCRETION; ACTIVE GALACTIC NUCLEI; MAGNETIC WHITE-DWARFS; BLACK-HOLES; X-RAY; LINE REGION; EMISSION; FLOWS; INSTABILITY AB We extend our previous numerical simulation of accretion disks with shock waves when cooling effects are also included. We consider bremsstrahlung and other power-law processes: Lambda proportional to p(2)T(alpha) to mimic cooling in our simulation. We employ the smoothed particle hydrodynamics technique as in the past. We observe that for a given angular momentum of the flow, the shock wave undergoes a steady, radial oscillation with the period roughly equal to the cooling time. Oscillations seem to take place when the disk and cooling parameters (i.e., accretion rate, cooling process) are such that the infall time from shock is of the same order as the postshock cooling time. The amplitude of oscillation could be up to 10% of the distance of the shock wave from the black hole when the black hole is accreting. When the accretion is impossible due to the centrifugal barrier, the amplitude variation could be much larger. As a result of the oscillation, the energy output from the disk is also seen to vary quasi-periodically. We believe that these oscillations might be responsible for the quasiperiodic oscillation (QPO) behaviors seen in several black hole candidates, in neutron star systems as well as dwarf novae candidates such as SS Cyg and VW Hyi. C1 UNIV HEIDELBERG,INST THEORET ASTROPHYS,D-69120 HEIDELBERG,GERMANY. UNIV HEIDELBERG,INTERDISCIPLINARES ZENTRUM WISSENSCH RECH,D-69120 HEIDELBERG,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. TATA INST FUNDAMENTAL RES,BOMBAY 400005,MAHARASHTRA,INDIA. RP Molteni, D (reprint author), UNIV PALERMO,I-90100 PALERMO,ITALY. NR 41 TC 152 Z9 152 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 FEB 1 PY 1996 VL 457 IS 2 BP 805 EP 812 DI 10.1086/176775 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600031 ER PT J AU Wolinski, KG Dolan, JF Boyd, PT Biggs, JD Nelson, MJ Percival, JW Taylor, M vanCitters, GW AF Wolinski, KG Dolan, JF Boyd, PT Biggs, JD Nelson, MJ Percival, JW Taylor, M vanCitters, GW TI The polarization of X-ray binaries in the ultraviolet .1. Cygnus XR-1, 4U 0900-40, AND 4U 1700-37 SO ASTROPHYSICAL JOURNAL LA English DT Article DE polarization; stars, individual (Cygnus XR-1, 4U 0900-40, 4U 1700-37); X-rays, stars ID WAVELENGTH DEPENDENCE; ABSORPTION-SPECTRUM; LINEAR-POLARIZATION; VELA X-1; INCLINATIONS AB Cyg XR-1, 4U 0900-40, and 4U 1700-37 were monitored polarimetrically and photometrically in the ultraviolet (UV) with the High Speed Photometer (HSP) on the Hubble Space Telescope (HST) at 6-10 different phases during a single binary orbit. Polarimetric observations were obtained in a bandpass centered at 2770 Angstrom; 4U 0900-40 was also monitored polarimetrically in a bandpass centered at 3270 Angstrom. Photometric observations were obtained in a bandpass centered at 2480 Angstrom. The UV polarization is variable in all three systems, consistent with a previously discovered intrinsic component of polarization attributed to scattering of light from the supergiant primary by a gas stream between the primary and the neutron star (4U 0900-40 and 4U 1700-37) or black hole (Cyg XR-1) secondary. The amplitude of the polarimetric variability is much larger in the UV than in the visible, confirming a prediction of the model that identifies Rayleigh scattering as the principal mechanism producing the intrinsic polarization. The polarimetric variability as a function of phase fits the standard scattering model of Brown, McLean, & Emslie only if an additional component of polarization occurs near first quadrature in the two systems with neutron star secondaries. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. PERTH OBSERV,BICKLEY,WA 6076,AUSTRALIA. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. UNIV WISCONSIN,SPACE ASTRON LAB,MADISON,WI 53706. LORAS COLL,DEPT PHYS & ENGN,DUBUQUE,IA 52004. NATL SCI FDN,DIV ASTRON SCI,ARLINGTON,VA 22230. RP Wolinski, KG (reprint author), SPACE TELESCOPE SCI INST,3700 SAN MARTIN DR,BALTIMORE,MD 21218, USA. RI Boyd, Patricia/D-3274-2012 NR 30 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 FEB 1 PY 1996 VL 457 IS 2 BP 859 EP 867 DI 10.1086/176781 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600037 ER PT J AU Golden, RL Stochaj, SJ Stephens, SA Aversa, F Barbiellini, G Boezio, M Bravar, U Colavita, A Fratnik, F Schiavon, P Vacchi, A Zampa, N Mitchell, JW Ormes, JF Streitmatter, RE Bellotti, R Cafagna, F Castellano, M Circella, M DeCataldo, G DeMarzo, C Giglietto, N Marangelli, B Raino, A Spinelli, P Bocciolini, M Finetti, N Papini, P Perego, A Piccardi, S Spillantini, P Basini, G Brancaccio, FM Ricci, M Brunetti, MT Codino, A Grimani, C Menichelli, M Bidoli, V Candusso, M Casolino, M DePascale, MP Morselli, A Picozza, P Sparvoli, R Hof, M Menn, W Simon, M AF Golden, RL Stochaj, SJ Stephens, SA Aversa, F Barbiellini, G Boezio, M Bravar, U Colavita, A Fratnik, F Schiavon, P Vacchi, A Zampa, N Mitchell, JW Ormes, JF Streitmatter, RE Bellotti, R Cafagna, F Castellano, M Circella, M DeCataldo, G DeMarzo, C Giglietto, N Marangelli, B Raino, A Spinelli, P Bocciolini, M Finetti, N Papini, P Perego, A Piccardi, S Spillantini, P Basini, G Brancaccio, FM Ricci, M Brunetti, MT Codino, A Grimani, C Menichelli, M Bidoli, V Candusso, M Casolino, M DePascale, MP Morselli, A Picozza, P Sparvoli, R Hof, M Menn, W Simon, M TI Measurement of the positron to electron ratio in the cosmic rays above 5 GeV SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; elementary particles AB As part of a series of experiments to search for antimatter in cosmic rays, the New Mexico State University balloon-borne magnet spectrometer was configured for a flight to study positrons. Two completely new instruments, a transition radiation detector and a silicon-tungsten imaging calorimeter, were added to the magnet spectrometer. These two detectors provided a proton rejection factor better than 3 x 10(4). This instrument was flown from Fort Sumner, New Mexico, at an average depth of 4.5 g cm(-2) of residual atmosphere for a period of 25 hr. We report here the measured fraction of positrons e(+)/(e(+) + e(-)) from similar to 5 to 60 GeV at the top of the atmosphere. Our measurements do not show any compelling evidence for an increase in this ratio with energy, and our results are consistent with a constant fraction of 0.078 +/- 0.016 over the entire energy region. C1 TATA INST FUNDAMENTAL RES, BOMBAY 400005, MAHARASHTRA, INDIA. UNIV TRIESTE, DIPARTIMENTO FIS, I-34147 TRIESTE, ITALY. SEZ IST NAZL FIS NUCL TRIESTE, I-34147 TRIESTE, ITALY. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV BARI, DIPARTMENTO FIS, I-70126 BARI, ITALY. SEZ IST NAZL FIS NUCL BARI, I-70126 BARI, ITALY. UNIV FLORENCE, DIPARTIMENTO FIS, I-50125 FLORENCE, ITALY. SEZ IST NAZL FIS NUCL FIRENZE, I-50125 FLORENCE, ITALY. IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY. UNIV PERUGIA, DIPARTIMENTO FIS, I-06100 PERUGIA, ITALY. SEZ IST NAZL FIS NUCL PERUGIA, I-06100 PERUGIA, ITALY. UNIV ROME, DIPARTIMENTO FIS, I-00133 ROME, ITALY. SEZ IST NAZL FIS NUCL ROMA, I-00133 ROME, ITALY. UNIV SIEGEN, D-57068 SIEGEN, GERMANY. RP NEW MEXICO STATE UNIV, BOX 3-PAL, LAS CRUCES, NM 88003 USA. RI Morselli, Aldo/G-6769-2011; giglietto, nicola/I-8951-2012; Castellano, Marcello/J-3428-2012; Cafagna, Francesco/A-9299-2010; Vacchi, Andrea/C-1291-2010; OI Morselli, Aldo/0000-0002-7704-9553; giglietto, nicola/0000-0002-9021-2888; Castellano, Marcello/0000-0002-4211-2903; Cafagna, Francesco/0000-0002-7450-4784; Vacchi, Andrea/0000-0003-3855-5856; SPINELLI, Paolo/0000-0001-6688-8864 NR 19 TC 70 Z9 70 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 FEB 1 PY 1996 VL 457 IS 2 BP L103 EP L106 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ548 UT WOS:A1996TQ54800013 ER PT J AU Sellgren, K Werner, MW Allamandola, LJ AF Sellgren, K Werner, MW Allamandola, LJ TI A survey of near-infrared emission in visual reflection nebulae SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE infrared, ISM, continuum; infrared, ISM, lines and bands; reflection nebulae ID POLYCYCLIC AROMATIC-HYDROCARBONS; IR EMISSION; SURFACE BRIGHTNESS; INTERSTELLAR DUST; MICRON EMISSION; BANDS; FEATURES; SPECTRUM; STARS; IDENTIFICATION AB We present a survey for extended 2.2 mu m emission in 20 new visual reflection nebulae, illuminated by stars with temperatures of 3600-33,000 K. We detect extended 2.2 mu m emission in 13 new nebulae, illuminated by stars with temperatures of 6800-33,000 K. For most of these 13 nebulae we have measured J - K, H - K, and K - L' and obtained surface brightness measurements at the wavelength of the 3.3 mu m emission feature. All the reflection nebulae with extended near-infrared emission in excess over scattered starlight have very similar near-infrared colors and show the 3.3 mu m feature in emission with similar feature-to-continuum ratios. The 3.3 mu m feature-to-continuum ratio ranges from similar to 3 to similar to 9, both within individual nebulae and from nebula to nebula, which suggests that the 3.3 mu m feature and its underlying continuum arise from different materials, or from different ranges of sizes within a size distribution of particles. No dependence on the temperature of the illuminating star is seen in the near-infrared colors or 3.3 mu m feature-to-continuum ratio, over a factor of 2 in stellar temperature. This is similar to our previous IRAS results, in which we found no dependence of the ratio of 12 mu m to 100 mu m surface brightnesses in reflection nebulae illuminated by stars with temperatures of 5000-33,000 K. C1 CALTECH, JET PROPULS LAB, PASADENA, CA 91109 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP OHIO STATE UNIV, DEPT ASTRON, 174 W 18TH AVE, COLUMBUS, OH 43210 USA. NR 69 TC 31 Z9 31 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 FEB PY 1996 VL 102 IS 2 BP 369 EP 382 DI 10.1086/192262 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ784 UT WOS:A1996TQ78400006 ER PT J AU Ellis, WG Thompson, AM Kondragunta, S Pickering, KE Stenchikov, G Dickerson, RR Tao, WK AF Ellis, WG Thompson, AM Kondragunta, S Pickering, KE Stenchikov, G Dickerson, RR Tao, WK TI Potential ozone production following convective transport based on future emission scenarios SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE ozone; convection; cloud outflow; predicted emissions ID TRACE GAS BUDGETS; 10-11 JUNE 1985; TROPOSPHERIC OZONE; SEASONAL CYCLES; SQUALL LINE; PRECIPITATION; CH4; DISTRIBUTIONS; ATMOSPHERE; INCREASE AB Current and projected (up to 2050 A.D.) concentrations of boundary layer trace gases, including NOx, CO, CH4, and several nonmethane hydrocarbons were redistributed throughout the troposphere in a simulation of a central U.S. squall line using the Goddard Cumulus Ensemble (GCE) convective cloud model. Vertical profiles of the redistributed trace gases were used in a one-dimensional photochemical model to determine the vertical profile of the potential production of O-3. Several different emission scenarios were considered. In the case where NOx emissions were doubled along with an increase in CO, CH4, and NMHC's, the middle troposphere showed an enhancement of 41% for O-3 production relative to the 1985 case. For the reduction scenario, where NOx emissions were decreased by a factor of two, the O-3 produced in the middle troposphere was reduced by 50%. Given the role of convection in the regional O-3 budget of the central U.S. during the summertime, our results suggest that substantial changes in emissions could bring about changes in mid-tropospheric O-3 large enough to be observed by satellite remote sensing. C1 UNIV MARYLAND,DEPT METEOROL,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. UNIV MARYLAND,DEPT CHEM,COLLEGE PK,MD 20742. UNIV MARYLAND,NASA,GSFC,JOINT CTR EARTH SYST SCI,GREENBELT,MD 20771. RI Kondragunta, Shobha/F-5601-2010; Pickering, Kenneth/E-6274-2012; Georgiy, Stenchikov/J-8569-2013; Dickerson, Russell/F-2857-2010; Thompson, Anne /C-3649-2014 OI Kondragunta, Shobha/0000-0001-8593-8046; Dickerson, Russell/0000-0003-0206-3083; Thompson, Anne /0000-0002-7829-0920 NR 36 TC 2 Z9 2 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1996 VL 30 IS 4 BP 667 EP 672 DI 10.1016/1352-2310(95)00318-5 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA TM513 UT WOS:A1996TM51300013 ER PT J AU Conkin, J Kumar, V Powell, MR Foster, PP Waligora, JM AF Conkin, J Kumar, V Powell, MR Foster, PP Waligora, JM TI A probabilistic model of hypobaric decompression sickness based on 66 chamber tests SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID ALTITUDE AB One consequence of the NASA tissue ratio (TR) model is that calculated probability of decompression sickness [P(DCS)] is constant in tests at different ambient pressures so long as the ratio of P1N(2) to P2 is the same in each test; P1N(2) is N-2 pressure in the 360 minute half-time compartment, and P2 is ambient pressure after decompression. We test the hypothesis that constant P(DCS) is better described by TRs that decrease as P2 decreases. Data were from 66 NASA and USAF hypobaric chamber tests resulting in 211 cases of DCS in 1075 exposures. The response variable was presence or absence of DCS while at P2. Explanatory variables were P1N(2), P2, exercise at P2, (yes or no), time to DCS (failure time), and time to end of test in those without DCS (censored time). Probability models were fitted using techniques from survival analysis. The log likelihood for the two parameter log logistic survival model was -846 with only failure and censored times, -801 when TR [P1N(2)/P2] plus exercise were added, and -663 when modified TR [(((P1N(2) + c1)/P2) - 1)(c2)] plus exercise were added, where c1 and c2 are fitted parameters in the five parameter model. Constant P(DCS) was better described by TRs that decrease as P2 decreases; a conclusion supported by additional empirical observations, and bubble growth models that are independent of DCS data. Exercise increased the P(Dcs) at P2. As a description of decompression ''dose'', the modified TR was superior to TR over a wider range of experimental conditions. C1 KRUG LIFE SCI,HOUSTON,TX. RP Conkin, J (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,SD5,HOUSTON,TX 77058, USA. NR 20 TC 29 Z9 32 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 FEB PY 1996 VL 67 IS 2 BP 176 EP 183 PG 8 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA TT661 UT WOS:A1996TT66100015 PM 8834946 ER PT J AU Giuliani, A LoGiudice, P Mancini, AM Quatrini, G Pacifici, L Webber, CL Zak, M Zbilut, JP AF Giuliani, A LoGiudice, P Mancini, AM Quatrini, G Pacifici, L Webber, CL Zak, M Zbilut, JP TI A Markovian formalization of heart rate dynamics evinces a quantum-like hypothesis SO BIOLOGICAL CYBERNETICS LA English DT Article ID TIME-SERIES AB Most investigations into heart rate dynamics have emphasized continuous functions, whereas the heart beat itself is a discrete event. We present experimental evidence that by considering this quality, the dynamics may be appreciated as a result of singular dynamics arising out of non-lipschitz formalisms. Markov process analysis demonstrates that heart beats may then be considered in terms of quantum-like constraints. C1 RUSH UNIV,DEPT MOLEC BIOPHYS & PHYSIOL,CHICAGO,IL 60612. SIGMA TAU PHARMACEUT CO,INST RES SENESCENCE,I-00040 POMEZIA,ITALY. LOYOLA UNIV,MED CTR,DEPT PHYSIOL,MAYWOOD,IL 60153. CALTECH,JET PROP LAB,PASADENA,CA 91109. RI Giuliani, Alessandro/K-7589-2016 OI Giuliani, Alessandro/0000-0002-4640-804X NR 35 TC 14 Z9 14 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0340-1200 J9 BIOL CYBERN JI Biol. Cybern. PD FEB PY 1996 VL 74 IS 2 BP 181 EP 187 DI 10.1007/BF00204206 PG 7 WC Computer Science, Cybernetics; Neurosciences SC Computer Science; Neurosciences & Neurology GA TT037 UT WOS:A1996TT03700009 PM 8634369 ER PT J AU Hummer, G Garde, S Garcia, AE Pohorille, A Pratt, LR AF Hummer, G Garde, S Garcia, AE Pohorille, A Pratt, LR TI Hydrophobic interactions: A fluctuation model. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP420 EP MP420 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201302 ER PT J AU Pohorille, A Wilson, MA Chipot, C AF Pohorille, A Wilson, MA Chipot, C TI Interactions of small solutes with membranes SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WAML9 EP WAML9 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202184 ER PT J AU Halpern, D AF Halpern, D TI Visiting TOGA's past SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SEA-SURFACE TEMPERATURE; EQUATORIAL PACIFIC-OCEAN; NINO SOUTHERN OSCILLATION; EL-NINO; NUMERICAL-SIMULATION; ATMOSPHERIC RESPONSE; TROPICAL PACIFIC; WIND; CIRCULATION; ANOMALIES AB The origin of the Tropical Oceans-Global Atmosphere (TOGA) Program was closely related to the response of global atmospheric circulation to sea surface temperature variations in the tropical Pacific Ocean, which is evident by the El Nino phenomenon. During the two decades before the 1985 start of TOGA, advancements in scientific understanding of the tropical ocean and global atmosphere and advancements in technology provided strong foundations for TOGA. By the early 1980s, research had demonstrated a strong linkage between tropical SST variations and global atmospheric circulation, and discussions of an international ocean-atmosphere program had begun. Probably the single most important event leading to the creation of TOGA was the unannounced arrival in 1982 of the largest El Nino in a century. RP Halpern, D (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 90 TC 7 Z9 7 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 1996 VL 77 IS 2 BP 233 EP 242 DI 10.1175/1520-0477(1996)077<0233:VTP>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB904 UT WOS:A1996UB90400002 ER PT J AU McPeters, RD Krueger, AJ Bhartia, PK AF McPeters, RD Krueger, AJ Bhartia, PK TI Spectral analyses, climatology, and interannual variability of Nimbus-7 TOMS version 6 total column ozone SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter ID WAVES AB An ozone climatology using space-time spectral analyses is now available as NASA Reference Publication RP-1360. This note gives a brief description of RP-1360 and examples of its graphics. The address for copies of the publication is given, along with the Internet route for obtaining tabulated data via ftp. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL POSTDOCTORAL RES ASSOCIATE,GREENBELT,MD 20771. RP McPeters, RD (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011, USA. RI McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 5 TC 1 Z9 1 U1 0 U2 1 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 FEB PY 1996 VL 77 IS 2 BP 353 EP 357 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB904 UT WOS:A1996UB90400011 ER PT J AU Hudnut, KW Shen, Z Murray, M McClusky, S King, R Herring, T Hager, B Feng, Y Fang, P Donnellan, A AF Hudnut, KW Shen, Z Murray, M McClusky, S King, R Herring, T Hager, B Feng, Y Fang, P Donnellan, A TI Co-seismic displacements of the 1994 Northridge, California, earthquake SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SAN-ANDREAS FAULT; CRUSTAL DEFORMATION; GEODETIC MEASUREMENT; SOUTHERN CALIFORNIA; VENTURA-BASIN; PARKFIELD; SEQUENCE; REGION; SPACE AB The 17 January 1994 Northridge, California, earthquake significantly deformed the Earth's crust in the epicentral region, Displacements of 66 survey stations determined from Global Positioning System (GPS) observations collected before and after the earthquake show that individual stations were uplifted by up to 417 +/- 5 mm and displaced horizontally by up to 216 +/- 3 mm. Using these displacements, we estimate parameters of a uniform-slip model. Fault geometry and slip are estimated independent of seismological information, using Monte Carlo optimization techniques that minimize the model residuals, The plane that best fits the geodetic data lies 1 to 2 km above the plane indicated by aftershock seismicity. Modeling for distributed slip on a coplanar, yet larger model fault indicates that a high-slip patch occurred up-dip and northwest of the mainshock hypocenter and that less than 1 m of slip occurred in the uppermost 5 km of the crust. This finding is consistent with the lack of clear surface rupture and with the notion that the intersection with the fault that ruptured in 1971 formed the up-dip terminus of slip in the Northridge earthquake. Displacements predicted by either of these simple models explain most of the variance in the data within 50 km of the epicenter. On average, however, the scatter of the residuals is twice the data uncertainties, and in some areas, there is significant systematic misfit to either model. The co-seismic contributions of aftershocks are insufficient to explain this mismatch, indicating that the source geometry is more complicated than a single rectangular plane. C1 UNIV CALIF LOS ANGELES, DEPT EARTH & SPACE SCI, LOS ANGELES, CA 90024 USA. US GEOL SURVEY, MENLO PK, CA 94025 USA. MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02146 USA. UNIV CALIF SAN DIEGO, SCRIPPS INST OCEANOG, INST GEOPHYS & PLANETARY PHYS, LA JOLLA, CA 92093 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Hudnut, KW (reprint author), US GEOL SURVEY, 525 S WILSON AVE, PASADENA, CA 91106 USA. RI Hudnut, Kenneth/B-1945-2009; Hudnut, Kenneth/G-5713-2010 OI Hudnut, Kenneth/0000-0002-3168-4797; NR 60 TC 59 Z9 62 U1 1 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD FEB PY 1996 VL 86 IS 1 SU S BP S19 EP S36 PN B PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TZ652 UT WOS:A1996TZ65200003 ER PT J AU Buyevich, YA AF Buyevich, YA TI Particle distribution in suspension shear flow SO CHEMICAL ENGINEERING SCIENCE LA English DT Article ID CONCENTRATED SUSPENSIONS; SELF-DIFFUSION; MIGRATION; SPHERES; RESUSPENSION; SYSTEMS AB The model of this paper is based on an earlier proposed constitutive equation that factors in all normal stresses originated by random particle fluctuations. This equation is used to describe the joint effect of thermal and shear-induced fluctuations on concentrational distributions in suspension flow. Averaged products of fluctuation velocity components are evaluated on the basis of a rational mechanics approach combined with a simple kinematic consideration. The momentum conservation equation for the dispersed phase of a suspension closed by this constitutive equation is applied to unidirectional shear flow in the gravity field and to rotational Couette flow. Coupling the thermal and shear-induced fluctuations results in a situation where the total volume of particles suspended in a given shear flow reaches a minimum at a finite particle size, all other things being equal. Additionally, the developed model provides a reasonable explanation for the particle distributions observed in Couette flow. For these flows, the momentum conservation equation can also be reformulated to yield a diffusion-like equation for the suspended particles. However, coefficients of mutual diffusion due to both thermal and shear-induced fluctuations are drastically different from corresponding self-diffusivities as regards both their scaling and their concentrational dependence. RP Buyevich, YA (reprint author), NASA,AMES RES CTR,NATL RES COUNCIL,MOFFETT FIELD,CA 94035, USA. NR 35 TC 21 Z9 21 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD FEB PY 1996 VL 51 IS 4 BP 635 EP 647 DI 10.1016/0009-2509(95)00243-X PG 13 WC Engineering, Chemical SC Engineering GA TR194 UT WOS:A1996TR19400011 ER PT J AU Akapo, SO Dimandja, JMD Matyska, MT Pesek, JJ AF Akapo, SO Dimandja, JMD Matyska, MT Pesek, JJ TI Synthesis of chemically bonded squalene(ane) phases for microcolumn gas chromatographic separation of low-molecular-weight hydrocarbons in extraterrestrial atmospheres SO CHROMATOGRAPHIA LA English DT Article DE gas chromatography; low-molecular-weight hydrocarbons; extraterrestrial atmospheres; chemically bonded squalene(ane) phase; C-13 and Si-29 CP-MAS NMR ID PERFORMANCE LIQUID-CHROMATOGRAPHY; STATIONARY PHASES; INTERMEDIATE; HYDROSILATION AB Chemically bonded squalane(ene) phases have been synthesized via a hydride modified silanization process using dimethylchlorosilane, triethoxysilane and trichlorosilane. The surface structure of the bonded phases were characterized with DRIFT and solid state NMR studies. The results of the latter indicate successful bonding of a non-terminal olefin to the silica surface and that bonding of individual squalene molecules appeared not to occur at the same site(s) presumably due to steric hindrance. Among the phases examined, the trichlorosilane-based material exhibits better chromatographic properties probably due to greater surface coverage and hence effective non-polar interaction between the solutes and the bonded ligands. Under isothermal conditions, the present packings produced fast and efficient separation of C-1-C-4 saturated hydrocarbons on shorter columns than similar columns containing alkyl- or bidentate alkyl-modified silica packings at low column head pressure and are thermally stable at temperatures up to 250 degrees C or higher. C1 SAN JOSE STATE UNIV,DEPT CHEM,SAN JOSE,CA 95192. RP Akapo, SO (reprint author), NASA,AMES RES CTR,MAIL STOP 239-12,MOFFETT FIELD,CA 94035, USA. NR 23 TC 14 Z9 15 U1 0 U2 2 PU FRIEDR VIEWEG SOHN VERLAG GMBH PI WIESBADEN 1 PA PO BOX 5829, W-6200 WIESBADEN 1, GERMANY SN 0009-5893 J9 CHROMATOGRAPHIA JI Chromatographia PD FEB PY 1996 VL 42 IS 3-4 BP 141 EP 146 DI 10.1007/BF02269643 PG 6 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UA532 UT WOS:A1996UA53200004 ER PT J AU Parry, ML Hossell, JE Jones, PJ Rehman, T Tranter, RB Marsh, JS Rosenzweig, C Fischer, G Carson, LG Bunce, RGH AF Parry, ML Hossell, JE Jones, PJ Rehman, T Tranter, RB Marsh, JS Rosenzweig, C Fischer, G Carson, LG Bunce, RGH TI Integrating global and regional analyses of the effects of climate change: A case study of land use in England and Wales SO CLIMATIC CHANGE LA English DT Article AB The purpose of this paper is to exemplify a means by which an integrated assessment can be made of global and regional effects on land use of climate change. This is achieved by use of data on the effects of climate change on world food prices as inputs to a regional land use allocation model. Data on world prices are drawn from a recent global study of climate change and crop yields. In a case study of England and Wales a land allocation model is used to infer changes of land use that are the product of the integrated effect of climate-induced global price changes aid climate-related changes of yield in England and Wales. This combination of changed prices and yield potential is used to calculate the land use providing the highest returns for each of 155,235 l km(2) cells of land in England and Wales for a future assumed for the year 2060 (without climate change) and then for that same environment with climate change. The difference between these two is then treated as an estimated effect resulting from climate change. C1 UNIV BIRMINGHAM, DEPT GEOG, BIRMINGHAM B15 2TT, W MIDLANDS, ENGLAND. UNIV READING, CTR AGR STRATEGY, READING RG6 2AT, BERKS, ENGLAND. UNIV READING, DEPT AGR, READING RG6 2AT, BERKS, ENGLAND. GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. INT INST APPL SYST ANAL, A-2361 LAXENBURG, AUSTRIA. INST TERR ECOL, MERLEWOOD RES STN, GRANGE OVER SANDS LA11 6JU, CUMBRIA, ENGLAND. RP Parry, ML (reprint author), UCL, DEPT GEOG, 26 BEDFORD WAY, LONDON WC1H 0AP, ENGLAND. NR 12 TC 16 Z9 16 U1 0 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD FEB PY 1996 VL 32 IS 2 BP 185 EP 198 DI 10.1007/BF00143709 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA TY838 UT WOS:A1996TY83800005 ER PT J AU Noor, AK Starnes, JH Peters, JM AF Noor, AK Starnes, JH Peters, JM TI Nonlinear and postbuckling responses of curved composite panels with cutouts SO COMPOSITE STRUCTURES LA English DT Article ID REDUCED BASIS TECHNIQUE AB The results of a detailed study of the nonlinear and postbuckling responses of curved unstiffened composite panels with central circular cutouts are presented. The panels are subjected to applied edge displacements and temperature changes. The analysis is based on a first-order shear-deformation Sanders-Budiansky type theory with the effects of large displacements, moderate rotations, transverse shear deformation and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in three sets of interrelated parameters; namely, the panel stiffnesses, the material properties of the individual layers, and the material properties of the constituents (fibers, matrix, interface and interphase). Numerical results are presented for cylindrical panels with central circular cutouts subjected to edge shortening and uniform temperature change, showing the effects of variations in the panel curvature, hole diameter, laminate stacking sequence and fiber orientation, on the nonlinear and postbuckling panel responses, and their sensitivity to changes in the various panel, layer and micromechanical parameters. RP Noor, AK (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 22 TC 9 Z9 9 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD FEB PY 1996 VL 34 IS 2 BP 213 EP 240 DI 10.1016/0263-8223(95)00147-6 PG 28 WC Materials Science, Composites SC Materials Science GA UC529 UT WOS:A1996UC52900008 ER PT J AU Pell, B Epstein, SL Levinson, R AF Pell, B Epstein, SL Levinson, R TI Introduction to the special issue on games: Structure and learning SO COMPUTATIONAL INTELLIGENCE LA English DT Editorial Material C1 CUNY HUNTER COLL,DEPT COMP SCI,NEW YORK,NY 10021. CUNY,GRAD SCH,NEW YORK,NY. UNIV CALIF SANTA CRUZ,DEPT COMP SCI,SANTA CRUZ,CA 95064. RP Pell, B (reprint author), NASA,AMES RES CTR,CAELUM RES CORP,AI RES BRANCH,MAIL STOP 269-2,MOFFETT FIELD,CA 94035, USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU BLACKWELL PUBLISHERS PI CAMBRIDGE PA 350 MAIN STREET, STE 6, CAMBRIDGE, MA 02148-5023 SN 0824-7935 J9 COMPUT INTELL JI Comput. Intell. PD FEB PY 1996 VL 12 IS 1 BP 1 EP 6 DI 10.1111/j.1467-8640.1996.tb00249.x PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA UC853 UT WOS:A1996UC85300001 ER PT J AU Pell, B AF Pell, B TI A strategic metagame player for general chess-like games SO COMPUTATIONAL INTELLIGENCE LA English DT Article DE games; metagame; heuristic search; evaluation-function learning; strategy; rule analysis; chess; knowledge representation; methodology; game generation AB This paper introduces METAGAMER, the first program designed within the paradigm of Metagame-playing (Metagame). This program plays games in the class of symmetric chess-like games, which includes chess, Chinese chess, checkers, draughts, and Shogi. METAGAMER takes as input the rules of a specific game and analyzes those rules to construct an efficient representation and an evaluation function for that game; they are used by a generic search engine. The strategic analysis performed by METAGAMER relates a set of general knowledge sources to the details of the particular game. Among other properties, this analysis determines the relative value of the different pieces in a given game. Although METAGAMER does not learn from experience, the values resulting from its analysis are qualitatively similar to values used by experts on known games and are sufficient to produce competitive performance the first time METAGAMER plays a new game. Besides being the first Metagame-playing program, this is the first program to have derived useful piece values directly from analysis of the rules of different games. This paper describes the knowledge implemented in METAGAMER, illustrates the piece values METAGAMER derives for chess and checkers, and discusses experiments with METAGAMER on both existing and newly generated games. RP Pell, B (reprint author), NASA,AMES RES CTR,CAELUM RES CORP,AI RES BRANCH,MAIL STOP 269-2,MOFFETT FIELD,CA 94035, USA. NR 46 TC 7 Z9 7 U1 2 U2 3 PU BLACKWELL PUBLISHERS PI CAMBRIDGE PA 350 MAIN STREET, STE 6, CAMBRIDGE, MA 02148-5023 SN 0824-7935 J9 COMPUT INTELL JI Comput. Intell. PD FEB PY 1996 VL 12 IS 1 BP 177 EP 198 DI 10.1111/j.1467-8640.1996.tb00258.x PG 22 WC Computer Science, Artificial Intelligence SC Computer Science GA UC853 UT WOS:A1996UC85300010 ER PT J AU Kulkarni, M Noor, AK AF Kulkarni, M Noor, AK TI Sensitivity analysis for the dynamic response of thermoviscoplastic shells of revolution SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID FINITE AB A computational procedure is presented for evaluating the sensitivity coefficients of the dynamic axisymmetric, fully-coupled, thermoviscoplastic response of shells of revolution. The analytical formulation is based on Reissner's large deformation shell theory with the effects of large-strain, transverse shear deformation, rotatory inertia and moments turning around the normal to the middle surface included. The material model is chosen to be viscoplasticity with strain hardening and thermal hardening, and an associated flow rule is used with a von Mises effective stress. A mixed formulation is used for the shell equations with the fundamental unknowns consisting of six stress resultants, three generalized displacements and three velocity components. The energy-balance equation is solved using a Galerkin procedure, with the temperature as the fundamental unknown. Spatial discretization is performed in one dimension (meridional direction) for the momentum and constitutive equations of the shell, and in two dimensions (meridional and thickness directions) for the energy-balance equation. The temporal integration is performed by using an explicit central difference scheme (leap-frog method) for the momentum equation; a predictor-corrector version of the trapezoidal rule is used for the energy-balance equation; and an explicit scheme consistent with the central difference method is used to integrate the constitutive equations. The sensitivity coefficients are evaluated by using a direct differentiation approach. Numerical results are presented for a spherical cap subjected to step loading. The sensitivity coefficients are generated by evaluating the derivatives of the response quantities with respect to the thickness, mass density, Young's modulus, two of the material parameters characterizing the viscoplastic response and the three parameters characterizing the thermal response. Time histories of the response and sensitivity coefficients are presented, along with spatial distributions of some of these quantities at selected times. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681. NR 12 TC 1 Z9 1 U1 1 U2 1 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 FEB PY 1996 VL 129 IS 4 BP 371 EP 391 DI 10.1016/0045-7825(95)00861-6 PG 21 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA UG132 UT WOS:A1996UG13200003 ER PT J AU Watson, BC Noor, AK AF Watson, BC Noor, AK TI Sensitivity analysis for large-deflection and postbuckling responses on distributed-memory computers SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article AB A computational strategy is presented for calculating sensitivity coefficients for the non-linear large-deflection and postbuckling responses of laminated composite structures on distributed-memory parallel computers. The strategy is applicable to any message-passing distributed computational environment. The key elements of the proposed strategy are: (a) a multiple-parameter reduced basis technique; (b) a parallel sparse equation solver based on a nested dissection (or multilevel substructuring) node ordering scheme; and (c) a multilevel parallel procedure for evaluating hierarchical sensitivity coefficients. The hierarchical sensitivity coefficients measure the sensitivity of the composite structure response to variations in three sets of interrelated parameters; namely, laminate, layer and micromechanical (fiber, matrix and interface/interphase) parameters. The effectiveness of the strategy is assessed by performing hierarchical sensitivity analysis for the large-deflection and postbuckling responses of stiffened composite panels with cutouts on three distributed-memory computers. The panels are subjected to combined mechanical and thermal loads. The numerical studies presented demonstrate the advantages of the reduced basis technique for hierarchical sensitivity analysis on distributed-memory machines. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681. NR 19 TC 9 Z9 9 U1 0 U2 0 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 FEB PY 1996 VL 129 IS 4 BP 393 EP 409 DI 10.1016/0045-7825(95)00862-4 PG 17 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA UG132 UT WOS:A1996UG13200004 ER PT J AU Rumsey, CL Sanetrik, MD Biedron, RT Melson, ND Parlette, EB AF Rumsey, CL Sanetrik, MD Biedron, RT Melson, ND Parlette, EB TI Efficiency and accuracy of time-accurate turbulent Navier-Stokes computations SO COMPUTERS & FLUIDS LA English DT Article ID FLOW AB The accuracy and efficiency of two different types of subiterations in both explicit and implicit Navier-Stokes codes are explored for unsteady laminar circular-cylinder flow and unsteady turbulent flow over an 18%-thick circular-are (biconvex) airfoil. Grid and time-step studies are used to assess the numerical accuracy of the methods. For both explicit and implicit algorithms, nonsubiterative time-stepping schemes and schemes with physical time subiterations are subject to time-step limitations in practice that are removed by pseudo time subiterations (dual time stepping). Computations for the circular-are airfoil indicate that a one-equation turbulence model predicts the unsteady separated flow better than an algebraic turbulence model; also, the hysteresis with Mach number of the self-excited unsteadiness due to shock and boundary-layer separation is well predicted. C1 ANALYT SERV & MAT INC, HAMPTON, VA 23666 USA. VIGYAN INC, HAMPTON, VA USA. RP Rumsey, CL (reprint author), NASA, LANGLEY RES CTR, MAIL STOP 128, HAMPTON, VA 23681 USA. NR 25 TC 50 Z9 56 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD FEB PY 1996 VL 25 IS 2 BP 217 EP 236 DI 10.1016/0045-7930(95)00043-7 PG 20 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA UA221 UT WOS:A1996UA22100008 ER PT J AU Inatomi, K Hochstein, LI AF Inatomi, K Hochstein, LI TI The purification and properties of a copper nitrite reductase from Haloferax denitrificans SO CURRENT MICROBIOLOGY LA English DT Article ID FAECALIS STRAIN S-6; ACHROMOBACTER-CYCLOCLASTES; ATP SYNTHASE; HALOBACTERIUM; PROTEIN; DEHYDROGENASE; BACTERIA AB A dissimilatory nitrite reductase from Haloferax denitrificans was purified to apparent electrophoretic homogeneity, The overall purification was 125-fold with about a 1% recovery of activity, The enzyme, which had a molecular mass of 127 kDa, was composed of a 64-kDa subunit as determined by SDS-PAGE, Although maximum activity occurred in the presence of 4 M NaCl, no activity was lost when the enzyme was incubated in the absence of NaCl, The absorption spectrum had maxima at 462, 594, and 682 nm, which disappeared upon reduction with dithionite. Diethyldithiocarbamate (DDC) was inhibitory, and the addition of copper sulfate to DDC-inhibited enzyme partially restored activity, These results suggest this enzyme is a copper-containing nitrite reductase and is the first such nitrite reductase to be described in an Archeon. C1 AMES RES CTR,MOFFETT FIELD,CA 94035. NR 26 TC 23 Z9 25 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0343-8651 J9 CURR MICROBIOL JI Curr. Microbiol. PD FEB PY 1996 VL 32 IS 2 BP 72 EP 76 DI 10.1007/s002849900013 PG 5 WC Microbiology SC Microbiology GA TM932 UT WOS:A1996TM93200004 ER PT J AU Weissman, PR AF Weissman, PR TI Star passages through the Oort cloud SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT International Meeting on Small Bodies in the Solar System and Their Interactions with the Planets CY AUG 08-12, 1994 CL MARIEHAMN, FINLAND DE Oort cloud; stellar perturbations; comet showers ID COMET SHOWERS; ORBITS AB Stars passing through the Oort cloud eject comets to interstellar space and initiate showers of comets into the planetary region. Monte Carlo simulations of such passages are performed on a representative distribution of cometary orbits. Ejected comets generally lie along a narrow tunnel ''drilled'' by the star through the cloud. However, shower comets come from the entire cloud, and do not give a strong signature of the star's passage, except in the inverse semimajor axis distribution for the shower comets. The planetary system is Likely not experiencing a cometary shower at this time. RP Weissman, PR (reprint author), CALTECH,JET PROP LAB,MAIL STOP 183-601,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 9 TC 18 Z9 18 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD FEB PY 1996 VL 72 IS 1-3 BP 25 EP 30 DI 10.1007/BF00117498 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA TZ604 UT WOS:A1996TZ60400006 ER PT J AU Harris, AW AF Harris, AW TI Effects of shape and spin on the tidal disruption of P/Shoemaker-Levy 9 SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT International Meeting on Small Bodies in the Solar System and Their Interactions with the Planets CY AUG 08-12, 1994 CL MARIEHAMN, FINLAND ID BODIES AB I derive an approximate criterion for the tidal disruption of a ''rubble pile'' body as it passes close to a planet (or the sun): rho(c) approximate to [2 rho(p)(R(p)/r)(3) + (omega/omega(0))(2)](a/b), where rho(c) is the critical density below which the body will be disrupted, rho(p) is the density of the planet (or sun), R(p) is the radius of the planet, r is the periapse distance, omega is the rotation frequency of the body, omega(0) is the surface orbit frequency about a body of unit density, and a/b is the axis ratio of the body, considered as a prolate ellipsoid. For P/Shoemaker Levy 9, in its passage close to Jupiter in 1992, this expression suggests that the critical density is similar to 1.2 for a spherical, non-spinning nucleus, but could be >2.5 for a 2:1 elongate body with a typical rotation period of similar to 10 hours. RP Harris, AW (reprint author), CALTECH,JET PROP LAB,MS 183-501,PASADENA,CA 91109, USA. NR 5 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD FEB PY 1996 VL 72 IS 1-3 BP 113 EP 117 DI 10.1007/BF00117510 PG 5 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA TZ604 UT WOS:A1996TZ60400018 ER PT J AU Rampino, MR Haggerty, BM AF Rampino, MR Haggerty, BM TI The ''Shiva hypothesis'': Impacts, mass extinctions, and the galaxy SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT International Meeting on Small Bodies in the Solar System and Their Interactions with the Planets CY AUG 08-12, 1994 CL MARIEHAMN, FINLAND ID CRETACEOUS-TERTIARY EXTINCTION; GEOLOGIC TIME SCALE; COMETARY IMPACTS; TERRESTRIAL IMPACT; TRIASSIC BOUNDARY; ASTEROID IMPACT; SOLAR COMPANION; SOUTH CHINA; PERIODICITY; IRIDIUM AB The ''Shiva Hypothesis'', in which recurrent, cyclical mass extinctions of life on Earth result from impacts of comets or asteroids, provides a possible unification of important processes in astrophysics, planetary geology, and the history of life. Collisions with Earth-crossing asteroids and comets greater than or equal to a few km in diameter are calculated to produce widespread environmental disasters (dust clouds, wildfires), and occur with the proper frequency to account for the record of five major mass extinctions (from greater than or equal to 10(8) Mt TNT impacts) and similar to 20 minor mass extinctions (from 10(7)-10(8) Mt impacts) recorded in the past 540 million years. Recent studies of a number of extinctions show evidence of severe environmental disturbances and mass mortality consistent with the expected after-effects (dust clouds, wildfires) of catastrophic impacts. At least six cases of features generally considered diagnostic of large impacts (e.g., large impact craters, layers with high platinum-group elements, shock-related minerals, and/or microtektites) are known at or close to extinction-event boundaries. Six additional cases of elevated iridium levels at or near extinction boundaries are of the amplitude that might be expected from collision of relatively low-Ir objects such as comets. The records of cratering and mass extinction show a correlation, and might be explained by a combination of periodic and stochastic impactors. The mass extinction record shows evidence for a periodic component of about 26 to 30 Myr, and an similar to 30 Myr periodic component has been detected in impact craters by some workers, with recent pulses of impacts in the last 2-3 million years, and at similar to 35, 65, and 95 million years ago. A cyclical astronomical pacemaker for such pulses of impacts may involve the motions of the Earth through the Milky Way Galaxy. As the Solar System revolves around the galactic center, it also oscillates up and down through the plane of the disk-shaped galaxy with a half-cycle similar to 30+/-3 Myr. This cycle should lead to quasi-periodic encounters with interstellar clouds, and periodic variations in the galactic tidal force with maxima at times of plane crossing. This ''galactic carrousel'' effect may provide a viable perturber of the Oort Cloud comets, producing periodic showers of comets in the inner Solar System. These impact pulses, along with stochastic impactors, may represent the major punctuations in earth history. C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP Rampino, MR (reprint author), NYU,EARTH SYST GRP,NEW YORK,NY 10003, USA. NR 111 TC 22 Z9 23 U1 3 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD FEB PY 1996 VL 72 IS 1-3 BP 441 EP 460 DI 10.1007/BF00117548 PG 20 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA TZ604 UT WOS:A1996TZ60400056 ER PT J AU Harris, AW AF Harris, AW TI Asteroids: Summary SO EARTH MOON AND PLANETS LA English DT Editorial Material RP Harris, AW (reprint author), CALTECH,JET PROP LAB,MS 183-501,PASADENA,CA 91109, USA. NR 0 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 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD FEB PY 1996 VL 72 IS 1-3 BP 489 EP 492 PG 4 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA TZ604 UT WOS:A1996TZ60400063 ER PT J AU Baroth, E Brunzie, T Hartsough, C McGregor, J Walsh, A Wells, G AF Baroth, E Brunzie, T Hartsough, C McGregor, J Walsh, A Wells, G TI An update on visual programming data acquisition software tools SO EE-EVALUATION ENGINEERING LA English DT Article RP Baroth, E (reprint author), CALTECH,JET PROP LAB,MEASUREMENT TEST & ENGN SUPPORT SECT,MEASUREMENT TECHNOL CTR,PASADENA,CA 91109, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU NELSON PUBLISHING PI NOKOMIS PA 2504 NORTH TAMIAMI TRAIL, NOKOMIS, FL 34275-3482 SN 0149-0370 J9 EE-EVAL ENG JI EE-Eval. Eng. PD FEB PY 1996 VL 35 IS 2 BP S26 EP & PG 9 WC Engineering, Electrical & Electronic SC Engineering GA TU007 UT WOS:A1996TU00700011 ER PT J AU Eldering, A Hall, JR Hussey, KJ Cass, GR AF Eldering, A Hall, JR Hussey, KJ Cass, GR TI Visibility model based on satellite-generated landscape data SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID DENVER BROWN CLOUD; LOS-ANGELES; OPTICAL-PROPERTIES; AEROSOLS; HAZE AB A model has been developed that uses simulated photographs to display the effect of atmospheric aerosols and gases on visibility. The model is driven by data on landscape features taken from earth-orbiting satellites, combined with digital terrain elevation data, and can be applied on a global scale. The effects of light scattering and absorption by atmospheric aerosols and gases on sky color and on the appearance of objects in the field of view are calculated. The results are displayed as a synthetic color photograph of the expected appearance of the scene. Quantitative comparisons are made between these synthetic images and actual photographs taken from the ground on the specific clear day and smog event days being simulated. C1 CALTECH,DEPT ENVIRONM ENGN SCI,PASADENA,CA 91125. CALTECH,ENVIRONM QUAL LAB,PASADENA,CA 91125. CALTECH,JET PROP LAB,PASADENA,CA 91125. NR 22 TC 6 Z9 6 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB PY 1996 VL 30 IS 2 BP 361 EP 370 DI 10.1021/es940717k PG 10 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA TT496 UT WOS:A1996TT49600020 ER PT J AU Greenleaf, JE Hutchinson, T ShafferBailey, M LooftWilson, R AF Greenleaf, JE Hutchinson, T ShafferBailey, M LooftWilson, R TI Exercise thermoregulation after 6 h of chair rest, 6 degrees head-down bed-rest, and water immersion deconditioning in men SO EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY LA English DT Article DE rectal temperature; mean skin temperature; blood flow; thermoregulation; deconditioning ID BLOOD-FLOW; TEMPERATURE; TILT AB The purpose was to investigate the mechanism for the excessive exercise hyperthermia following deconditioning (reduction of physical fitness). Rectal (T-re) and mean skin ((T) over bar(sk)) temperatures and thermoregulatory responses were measured in six men [mean (SD) age, 32 (6) years; mass, 78.26 (5.80) kg; surface area, 1.95 (0.11) m(2); maximum oxygen uptake (V over dot O-2max), 48 (6) ml . min(-1). kg(-1); whilst supine in air at dry bulb temperature 23.2 (0.6)degrees C, relative humidity 31.1 (11.1)% and air speed 5.6 (0.1) m . min(-1)] during 70 min of leg cycle exercise [51 (4)% V over dot O-2max] in ambulatory control (AC), or following 6 h of chair rest (CR), 6 degrees head-down bed rest (BR), and 20 degrees (WI20) and 80 degrees (WI80) foot-down water immersion [water temperature, 35.0 (0.1)degrees C]. Compared with the AC exercise Delta T-re [mean (SD) 0.77 (0.13)degrees C], Delta T-re after CR was 0.83 (0.08)degrees C (NS), after BR 0.92 (0.13)degrees C (*P < 0.05), after WI80 0.96 (0.13)degrees C*, and after WI20 1.03 (0.09)degrees C*. All (T) over bar(sk) responded similarly to exercise: they decreased (NS) by 0.5-0.7 degrees C in minutes 4-8 and equilibrated at +0.1 to +0.5 degrees C at 60-70. Skin heat conductance was not different among the five conditions (range = 147-159 kJ . m(-2). h(-1).degrees C-1). Results from an intercorrelation matrix suggested that total body sweat rate was more closely related to T-re at 70 min (T-re70) than limb sweat rate or blood flow. Only 36% of the variability in T-re70 could be accounted for by total sweating, and less than 10% from total body dehydration. It would appear that multiple factors are involved which may include change in sensitivity of thermo- and osmoreceptors. RP Greenleaf, JE (reprint author), NASA,AMES RES CTR,GRAVITAT RES BRANCH,LAB HUMAN ENVIRONM PHYSIOL 239 11,MOFFETT FIELD,CA 94035, USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0301-5548 J9 EUR J APPL PHYSIOL O JI Eur. J. Appl. Physiol. Occup. Physiol. PD FEB PY 1996 VL 72 IS 4 BP 303 EP 309 DI 10.1007/BF00599689 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA TV910 UT WOS:A1996TV91000004 PM 8851898 ER PT J AU Jurewicz, AJG Mittlefehldt, DW Jones, JH AF Jurewicz, AJG Mittlefehldt, DW Jones, JH TI Experimental partial melting of the St Severin (LL) and Lost City (H) chondrites - Reply SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID ORIGIN C1 NASA,LYNDON B JOHNSON SPACE CTR,EXPTL PLANETOL BRANCH,HOUSTON,TX 77058. RP Jurewicz, AJG (reprint author), LOCKHEED ENGN & SCI CO,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 4 TC 0 Z9 0 U1 2 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 FEB PY 1996 VL 60 IS 3 BP 543 EP 543 DI 10.1016/0016-7037(95)00372-X PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV457 UT WOS:A1996TV45700015 ER PT J AU Woronow, A Reid, AM Jones, JH AF Woronow, A Reid, AM Jones, JH TI Parental magma compositions inferred from the chemical compositions of olivine-controlled derivative melts SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PARTITION-COEFFICIENTS; LIQUID; TEMPERATURE; PRESSURE AB The melt portion of a parental magma, undergoing equilibrium olivine crystallization, passes through a succession of compositions unique to its initial composition. Because the succession of compositions follows uniquely from the parental magma's composition, a liquid line of descent model fit to several of the derivative-melt compositions can recover an estimate of the parental magma's composition. We have developed an algorithm to accomplish the model fitting and thus far equipped it to treat olivine fractionation including departures from perfect equilibrium crystallization. Here we report validation tests on the method, which we call ''Derivative-Magma Analysis'' (DMA), applied to computer-synthesized data and two instances of laboratory-synthesized data (one as a single-blind test). For the computer- and laboratory-synthesized data, DMA recovered the parental-magma compositions within common analytical accuracy. For the most difficult oxide to estimate, MgO, the recovered values deviated from the measured values by less than 0.5 wt% for the two laboratory-synthesized datasets. For other major-element oxides, recovered values typically deviate from nominal values by less than 0.2 wt%. DMA also reliably estimated the compositions of the olivines that coexisted with each derivative melt. Applied to the Kilauean summit eruption of 1959, DMA estimates a parental magma with Mg# = 73 (MgO approximate to 16 wt%). This value, while significantly higher than estimates from some authors who favor low-Mg parental magmas, rules out the extremely high-MgO parental magmas favored by other authors. C1 NASA,JSC,HOUSTON,TX 77058. RP Woronow, A (reprint author), UNIV HOUSTON,DEPT GEOSCI,HOUSTON,TX 77204, USA. NR 30 TC 0 Z9 0 U1 1 U2 1 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 FEB PY 1996 VL 60 IS 4 BP 577 EP 586 DI 10.1016/0016-7037(95)00414-9 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV810 UT WOS:A1996TV81000003 ER PT J AU Rothermel, J Bowdle, DA Srivastava, V AF Rothermel, J Bowdle, DA Srivastava, V TI Mid-tropospheric aerosol backscatter background mode over the Pacific Ocean at 9.1 mu m wavelength SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PROFILES AB The first atmospheric aerosol backscatter measurements at the rare isotope CO2 wavelength of 9.1 mu m were obtained in the troposphere over the Pacific Ocean in May-June 1990. A distinct aerosol backscatter background mode was found in both hemispheres with modal value similar to 10(-10) m(2)kg(-1)sr(-1) (backscatter normalized by air density), remarkably consistent with ground-based and airborne backscatter climatologies collected at other wavelengths, locations, and times. RP Rothermel, J (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,GLOBAL HYDROL & CLIMATE CTR,977 EXPLORER BLVD,HUNTSVILLE,AL 35806, USA. NR 18 TC 8 Z9 8 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 FEB 1 PY 1996 VL 23 IS 3 BP 281 EP 284 DI 10.1029/96GL00047 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TU593 UT WOS:A1996TU59300019 ER PT J AU Zurek, RW Manney, GL Miller, AJ Gelman, ME Nagatani, RM AF Zurek, RW Manney, GL Miller, AJ Gelman, ME Nagatani, RM TI Interannual variability of the north polar vortex in the lower stratosphere during the UARS mission SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WINTER; OZONE AB Northern winters since the 1991 launch of UARS are compared to earlier years (1978-1991) with respect to the potential for formation of Polar Stratospheric Clouds and for isolation of the north polar vortex. Daily NMC temperature minima at 465 K late in the 1993-94 winter and again in December 1994 were the lowest values experienced at those times of year (since 1978). Northern PV gradients were unusually strong in 1991-92 prior to late January and throughout the winter in both 1992-93 and 1994-95. Of all northern winters since 1978, 1994-95 with its early extended cold spell and persistently strong PV gradients most resembled the Antarctic winter lower stratosphere. Even so, temperatures were never as low, nor was the polar vortex as large, as during a typical southern winter. Judged by daily temperature minima and PV gradients at 465 K, meteorological conditions in the Arctic winter lower stratosphere during the UARS period were more conducive to vortex ozone loss by heterogeneous chemistry than in most previous winters since 1975-79. C1 NOAA,NATL METEOROL CTR,CLIMATE ANAL CTR,WASHINGTON,DC. RP Zurek, RW (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 17 TC 59 Z9 60 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 FEB 1 PY 1996 VL 23 IS 3 BP 289 EP 292 DI 10.1029/95GL03336 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TU593 UT WOS:A1996TU59300021 ER PT J AU Planet, WG Miller, AJ DeLuisi, JJ Hofmann, DJ Oltmans, SJ Wild, JD McDermid, IS McPeters, RD Connor, BJ AF Planet, WG Miller, AJ DeLuisi, JJ Hofmann, DJ Oltmans, SJ Wild, JD McDermid, IS McPeters, RD Connor, BJ TI Comparison of NOAA-11 SBUV/2 ozone vertical profiles with correlative measurements SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC OZONE AB Vertical profiles of ozone have been determined from observations with the Solar Backscatter Ultraviolet (SBUV/2) instrument on the NOAA-11 operational satellite. These observations began in January 1989 and continue to early 1995. Comparisons have been made with selected sets of ozone vertical profiles derived from an ensemble of satellite and land-based measurements. These include; 1) lidar and microwave measurements performed at Table Mountain, CA. 2) Umkehr observations with a mid-northern latitude set of Dobson spectrophotometers. 3) balloon ozonesondes launched from Boulder, CO. 4) measurements with the NASA SBUV on Nimbus-7. Overall, the SBUV/2 profiles within the altitude range of 1-20mb agree with the other measurements to about +/-5% with a -3 to -5% bias, the SBUV/2 values being lower. This level of agreement is consistent with the expected performance of the SBUV/2 instrument based on an extensive characterization of the instrument both in pre-launch calibration and in-orbit performance and also with current understanding of the test optical components used in pre-flight calibration. C1 NOAA,NATL METEOROL CTR,CLIMATE ANAL CTR,CAMP SPRINGS,MD. NOAA,AIR RESOURCES LAB,BOULDER,CO 80303. NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. RES & DATA SYST CORP,GREENBELT,MD. CALTECH,JET PROPULS LAB,PASADENA,CA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP Planet, WG (reprint author), NOAA,OFF RES & APPLICAT,SATELLITE RES LAB,CAMP SPRINGS,MD, USA. RI McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 11 TC 7 Z9 7 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 FEB 1 PY 1996 VL 23 IS 3 BP 293 EP 296 DI 10.1029/96GL00049 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TU593 UT WOS:A1996TU59300022 ER PT J AU Harries, J Ruth, S Russell, JM AF Harries, J Ruth, S Russell, JM TI On the distribution of mesospheric molecular hydrogen inferred from HALOE measurements of H2O and CH4 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC WATER-VAPOR; MIDDLE ATMOSPHERE; N2O; CO; NIMBUS-7; SAMS AB The Halogen Occultation Experiment (HALOE) is in orbit on NASA's Upper Atmosphere Research Satellite (UARS), and has been used to make measurements of a number of stratospheric and mesospheric constituents since October 1991. These include, amongst others, water vapour, H2O, and methane, CH4, two principal components of the total hydrogen budget of the middle atmosphere. The third main component is molecular hydrogen, H-2, which is not measurable by HALOE or any other UARS sensor. By making the assumption that the total hydrogen content of the middle atmosphere is a conserved quantity, and that these three constituents dominate the budget, it is possible to infer the H-2 fields in the mesosphere from the HALOE H2O and CH4 measurements. C1 RUTHERFORD APPLETON LAB,CHILTON,ENGLAND. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP Harries, J (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,SPACE & ATMOSPHER PHYS GRP,LONDON SW7 2AZ,ENGLAND. NR 27 TC 20 Z9 21 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 FEB 1 PY 1996 VL 23 IS 3 BP 297 EP 300 DI 10.1029/95GL03197 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TU593 UT WOS:A1996TU59300023 ER PT J AU Pulkkinen, TI Baker, DN Walker, RJ Raeder, J AshourAbdalla, M AF Pulkkinen, TI Baker, DN Walker, RJ Raeder, J AshourAbdalla, M TI Comparison of empirical field models and global MHD simulations: The near-tail currents (vol 22, pg 675, 1995) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Correction, Addition C1 FINNISH METEOROL INST,SF-00101 HELSINKI,FINLAND. RP Pulkkinen, TI (reprint author), NASA,HUGHES STX CORP,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI Pulkkinen, Tuija/D-8403-2012 OI Pulkkinen, Tuija/0000-0002-6317-381X NR 6 TC 0 Z9 0 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 FEB 1 PY 1996 VL 23 IS 3 BP 315 EP 316 PG 2 WC Geosciences, Multidisciplinary SC Geology GA TU593 UT WOS:A1996TU59300028 ER PT J AU Paylor, ED Baltuck, M AF Paylor, ED Baltuck, M TI Satellites and remote sensing SO GEOTIMES LA English DT Article RP Paylor, ED (reprint author), NASA,OFF MISSION PLANET EARTH,WASHINGTON,DC 20546, 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 FEB PY 1996 VL 41 IS 2 BP 42 EP 43 PG 2 WC Geosciences, Multidisciplinary SC Geology GA UW268 UT WOS:A1996UW26800033 ER PT J AU Jacobson, NS AF Jacobson, NS TI Twin Knudsen cell configuration for activity measurements by mass spectrometry SO HIGH TEMPERATURE AND MATERIALS SCIENCE LA English DT Article DE double Knudsen cell configuration; mass spectrometry; activity measurements ID ALLOYS; THERMODYNAMICS; FE; NI; CR AB A twin Knudsen cell apparatus for alloy activity measurements by mass spectrometry is described. Two Knudsen cells-one containing an alloy and one containing a pure component-are mounted on a single flange and translated into the sampling region via a motorized x-y table. Mixing of the molecular beams from the cells is minimized by a novel system of shutters. Activity measurements were taken on two well-characterized alloys to verify the operation of the system. Silver activity measurements are reported for Ag-Cu alloys and aluminum activity measurements are reported for Fe-Al alloys. The temperature dependence of activity for a 0.474 mol fraction Al-Fe alloy gives a partial molar heat of aluminum. Measurements taken with the twin cell show good agreement with literature values for these alloys. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RI Jacobson, Nathan/A-9411-2009 NR 22 TC 2 Z9 2 U1 0 U2 0 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 SN 1080-1278 J9 HIGH TEMP MAT SCI JI High. Temp. Mat. Sci. PD FEB PY 1996 VL 35 IS 1 BP 1 EP 9 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA TT135 UT WOS:A1996TT13500001 ER PT J AU Jenkins, JM Doyle, LR Cullers, DK AF Jenkins, JM Doyle, LR Cullers, DK TI A matched filter method for ground-based sub-noise detection of terrestrial extrasolar planets in eclipsing binaries: Application to CM Draconis SO ICARUS LA English DT Article ID SYSTEMS; STARS; CRITERIA; SEARCH AB The photometric detection of extrasolar planets by transits in eclipsing binary systems can be significantly improved by cross-correlating the observational light curves with synthetic models of possible planetary transit features, essentially a matched filter approach. We demonstrate the utility and application of this transit detection algorithm for ground-based detections of terrestrial-sized (Earth-to-Neptune radii) extrasolar planets in the dwarf M-star eclipsing binary system CM Draconis. Preliminary photometric observational data of this system demonstrate that the observational noise is well characterized as white and Gaussian at the observational time steps required for precision photometric measurements. Depending on planet formation scenarios, terrestrial-sized planets may form quite close to this low-luminosity system. We demonstrate, for example, that planets as small as 1.4 Earth radii with periods on the order of a few months in the CM Draconis system could be detected at the 99.9% confidence level in less than a year using l-m class telescopes from the ground. This result contradicts commonly held assumptions limiting present ground-based efforts to, at best, detections of gas giant planets after several years of observation. This method can be readily extended to a number of other larger star systems with the utilization of larger telescopes and longer observing times. Its extension to spacecraft observations should also allow the determination of the presence of terrestrial-sized planets in nearly 100 other known eclipsing binary systems. (C) 1996 Academic Press, Inc. RP Jenkins, JM (reprint author), NASA,AMES RES CTR,SETI INST,MS 245-3,MOFFETT FIELD,CA 94035, USA. FU EAPO CDC HHS [NCC 2-TEP] NR 33 TC 42 Z9 42 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 FEB PY 1996 VL 119 IS 2 BP 244 EP 260 DI 10.1006/icar.1996.0018 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000002 PM 11539178 ER PT J AU French, RG Roques, F Nicholson, PD McGhee, CA Bouchet, P Maene, SA Mason, EC Matthews, K Mosqueira, I AF French, RG Roques, F Nicholson, PD McGhee, CA Bouchet, P Maene, SA Mason, EC Matthews, K Mosqueira, I TI Earth-based detection of Uranus' lambda ring SO ICARUS LA English DT Article ID URANIAN RINGS; OCCULTATION OBSERVATIONS; VOYAGER-2; NEPTUNE; SYSTEM AB The 11 July 1992 occultation of Uranus by U103 (m(K) = 10.1) was observed using the 5-m Hale telescope on Palomar Mountain in California, the 4-m telescope at Cerro Tololo Inter-American Observatory (CTIO) in Chile, and the nearby 2.2-m telescope at European Southern Observatory (ESO). All observations were taken using InSb aperture photometers and K (lambda similar to 2.2 mu m) filters and provided high-quality profiles of the uranian rings. The ESO and Palomar ring event times have been incorporated into a comprehensive orbit model for the elliptical rings using all available Earth-based and Voyager occultation data, The kinematical model was used to determine the radius scale and geometry of the U103 occultation, as well as to provide absolute timing calibration for the CTIO light curve, which was reconstructed from two-dimensional digital scans of a high-speed strip chart, All nine classical rings were clearly observed during both ingress and egress. In addition, a sharp feature appeared in the CTIO ingress light curve with an orbital radius of 50,026.89 +/- 0.39 km, very close to the mean radius of the lambda ring of 50,026.3 +/- 0.6 km found by M. R, Showalter (Science 267, 490-493, 1995) from an analysis of Voyager 2 images. The CTIO feature is well above the noise: its equivalent width of E = 0.32 +/- 0.14 km corresponds to a 5-sigma detection. It is the only such signature in the entire CTIO lightcurve, other than the previously known rings. The characteristic ring-like shape of the profile, its high SNR, and its radial location all support the identification of this feature as an Earth-based detection of the lambda ring. At the same time, if the ring were azimuthally homogeneous with E greater than or similar to 0.32 km, it would have been clearly visible in the CTIO egress and Palomar light curves, but no such features were found, The A ring is thus azimuthally clumpy, resembling to some degree Neptune's are-like Adams ring. At the nearby ESO station, a suggestive ingress feature appeared with a radius of 50,023.01 +/- 0.28 km, but the data are too noisy to permit a positive identification; The orbital characteristics of the A ring and its azimuthal brightness profile cannot be uniquely extrapolated from the Voyager encounter epoch to the time of the U103 occultation because the mean motion and orbital radius of the ring are too uncertain. However, additional detections in archival Earth-based occultation data or from future observations could allow a much better determination of the dynamics of this dusty and clumpy ring. (C) 1996 Academic Press, Inc. C1 OBSERV PARIS, F-92195 MEUDON, FRANCE. CORNELL UNIV, DEPT ASTRON, ITHACA, NY 14853 USA. EUROPEAN SO OBSERV, LA SILLA, CHILE. PENN STATE UNIV, DEPT ASTRON, UNIVERSITY PK, PA 16802 USA. BRANSON SCH, ROSS, CA 94957 USA. CALTECH, PALOMAR OBSERV, PASADENA, CA 91125 USA. AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP French, RG (reprint author), WELLESLEY COLL, DEPT ASTRON, WELLESLEY, MA 02181 USA. NR 23 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 1996 VL 119 IS 2 BP 269 EP 284 DI 10.1006/icar.1996.0020 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000004 ER PT J AU Horn, LJ Cuzzi, JN AF Horn, LJ Cuzzi, JN TI Characteristic wavelengths of irregular structure in Saturn's B ring SO ICARUS LA English DT Article ID PARTICLE EROSION MECHANISMS; ELECTROSTATIC DISCHARGES; BALLISTIC TRANSPORT; OCCULTATION; VOYAGER-2; SYSTEMS; 28-SGR AB We have analyzed the spatial structure in Saturn's B and A rings for regional variations in characteristic spatial scales. To do this, we obtained radial scans of the reflectivity of the rings from the highest resolution full radial scan of the lit face of the rings in the Voyager image data set. The images were obtained in the Voyager 2 narrow angle camera, clear filter and have a resolution of approximately 5 km/pixel in the radial direction (the scans are slightly oversampled to 3.5 km). The radial scans were analyzed using a Burg maximum entropy technique to obtain spatial frequency spectra as a function of radial location in the B ring, Comparisons were made of the Burg technique and FFT techniques, and estimates of the limitations of the method were made. We find that the main rings display characteristic structure on several scales that vary with location. In the inner B ring (between the inner edge and around 99,000 km), a characteristic scale of 80-100 km is found. Between 99,000 and 103,500 ion, the 80-100 km scale vanishes and a strong preference for a longer wavelength (200-300 km) is seen. In this region, finer scale structure (20-40 km scale) is seen in abundance. This scale structure is absent in the inner B ring. The region between 103,500 and 116,000 ion has a very strong preference for 200-300 km scale structure and is practically devoid of fine scale structure except for a handful of isolated bursts. None of these bursts correspond to known strong resonances, Outside of 116,000 km, fine scale structure again appears in abundance, on top of the 200-300 km scale, and covers the ring to its outer edge. The Mimas 4:2 bending wave is clearly seen, but is responsible for only a very small fraction of the observed fine structure. (C) 1996 Academic Press, Inc. C1 AMES RES CTR,MOFFETT FIELD,CA 94035. RP Horn, LJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 183-501,PASADENA,CA 91109, USA. NR 39 TC 31 Z9 31 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 FEB PY 1996 VL 119 IS 2 BP 285 EP 310 DI 10.1006/icar.1996.0021 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000005 ER PT J AU Sada, PV Beebe, RF Conrath, BJ AF Sada, PV Beebe, RF Conrath, BJ TI Comparison of the structure and dynamics of Jupiter's Great Red Spot between the Voyager 1 and 2 encounters SO ICARUS LA English DT Article AB We have consistently navigated the highest resolution images available of Jupiter's Great Red Spot (GRS) from the Voyager ISS experiment. From them we have measured apparent displacements of cloud features around and within the Red Spot which can be interpreted as wind vectors. We have used the wind field information to determine the circulation characteristics of the collar and to map the relative vorticity and horizontal divergence of the central GRS region, Color ratios and ground-based data have been used to complement these observations. Derived quantities from the IRIS data set taken simultaneously with the Voyager images have been obtained in order to determine the thermal structure, infrared cloud opacity, NH3 abundance, and para H-2 fraction above the Great Red Spot, There is evidence of non-chaotic activity in the central region of the Red Spot. Small eddy structures consisting of coherent cloud features with apparently two-dimensional turbulent motions are present in this region along with larger classical cyclonic vortices, The surrounding anticyclonic collar circulates with higher velocities and appears to be detached from the core by an abrupt transition region, The central region appears to be elevated over the surrounding collar and exhibits evidence for upwelling and some outflow of material. Differences in the collar structure and velocity profiles between the Voyager encounters can be attributed to differences in the ingestion rate of westward-moving South Equatorial Belt vortices caused by a blocking South Tropical Zone Disturbance which, moving eastward, overtook and passed the Red Spot between the two encounters. This disturbance appears to temporarily increase in brightness during conjunctions with the Red Spot and has been tracked for 20 years. (C) 1996 Academic Press, Inc. C1 NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. RP Sada, PV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693 2,GREENBELT,MD 20771, USA. NR 42 TC 41 Z9 41 U1 1 U2 2 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 FEB PY 1996 VL 119 IS 2 BP 311 EP 335 DI 10.1006/icar.1996.0022 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000006 ER PT J AU Smith, PH Lemmon, MT Lorenz, RD Sromovsky, LA Caldwell, JJ Allison, MD AF Smith, PH Lemmon, MT Lorenz, RD Sromovsky, LA Caldwell, JJ Allison, MD TI Titan's surface, revealed by HST imaging SO ICARUS LA English DT Article ID ATMOSPHERE; ROTATION; NEPTUNE; URANUS; OCEAN AB We present for the first time relative albedo maps of Titan's surface. The maps were made from images taken by the Hubble Space Telescope's planetary camera (295 km per pixel) through atmospheric windows at 940 and 1080 nm. Coverage at all longitudes and between 45 degrees S and 60 degrees N was obtained with 14 orbits from 4-18 October 1994. Each image is characterized by haze with both limb effects (brightening) and a large north-south contrast. Subtracting an averaged image from each frame removes haze effects and reveals surface features of similar to 10% maximum contrast. Many features are clearly visible in multiple images and in both filters, but the surface map is dominated by a large, bright, roughly rectangular feature centered at 110 degrees W, 10 degrees S and elongated in an east-west direction (4000 x 2500 km(2)): this feature and others indicate the diversity of Titan's surface. We consider the origin of the bright feature in an otherwise dark landscape and suggest that highland washing by methane rainfall is a likely mechanism. (C) 1996 Academic Press, Inc. C1 UNIV WISCONSIN,CTR SPACE SCI & ENGN,MADISON,WI 53706. INST SPACE & TERR SCI,CONCORD,ON,CANADA. NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP Smith, PH (reprint author), UNIV ARIZONA,DEPT PLANETARY SCI,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA. RI Lemmon, Mark/E-9983-2010; Lorenz, Ralph/B-8759-2016 OI Lemmon, Mark/0000-0002-4504-5136; Lorenz, Ralph/0000-0001-8528-4644 NR 34 TC 182 Z9 182 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 FEB PY 1996 VL 119 IS 2 BP 336 EP 349 DI 10.1006/icar.1996.0023 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000007 ER PT J AU Achterberg, RK Flasar, FM AF Achterberg, RK Flasar, FM TI Planetary-scale thermal waves in Saturn's upper troposphere SO ICARUS LA English DT Article ID RADIO OCCULTATION MEASUREMENTS; VOYAGER INFRARED OBSERVATIONS; ROTATION PERIOD; POLAR HEXAGON; GRAVITY-WAVES; TIME-SERIES; SPACED DATA; ATMOSPHERE; JUPITER; STRATOSPHERE AB We have used temperatures retrieved from the Voyager IRIS (Infrared Interferometer Spectrometer) data at pressures of 130 and 270 mbar to search for waves in the upper troposphere of Saturn. The data are from three global mapping sequences taken by Voyagers 1 and 2, which together provide coverage between 60 degrees 5 and 80 degrees N latitudes. To analyze the temperatures, we grouped them within 10 degrees wide latitude bins and applied a periodogram analysis of their zonal variance. Since the data for each map were taken over periods of 12 to 18 hours, the phase velocity of any spectral component identified is ambiguous. We estimated the phase velocity of these components by varying the assumed phase velocity to maximize the amplitude of the periodogram response at integer tend wavenumbers. The results are dominated by zonal wavenumber 2 at 130 mbar in northern midlatitudes. In the Voyager 1 data this component is statistically significant at the 99% confidence level over latitudes 20 degrees N to 40 degrees N; the zonal phase of the wave is roughly constant over this latitude range. Estimates of the phase velocity using the combined Voyager 1 inbound and outbound maps allow a solution for the midlatitude zonal wavenumber 2 wave that is quasi-stationary in the reference frame defined by the rotation period of Saturn's magnetic field. Raytracing models suggest that the midlatitude waves are quasi-stationary Rossby waves. The waves are confined meridionally by meridional variations of the zonal mean winds, and confined vertically by variations in the static stability of Saturn's atmosphere. The meridional structure of these features suggests that they may be excited by overreflection of waves incident on a critical surface at midlatitudes, and that the low phase velocities are a consequence of the gradient in potential vorticity vanishing where the zonal winds are small. The waves can leak into the upper stratosphere, saturating or ''breaking'' at pressure levels similar to 10(-2)-10(-1) mbar. The viscous damping times are similar to 10 years, comparable to the radiative damping time in the tropopause region and in the stratosphere. (C) 1996 Academic Press, Inc. C1 SCI SYST & APPLICAT INC,LANHAM,MD 20706. RP Achterberg, RK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693 2,GREENBELT,MD 20771, USA. RI Flasar, F Michael/C-8509-2012 NR 53 TC 24 Z9 24 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 FEB PY 1996 VL 119 IS 2 BP 350 EP 369 DI 10.1006/icar.1996.0024 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000008 ER PT J AU Lamy, PL Toth, I Grun, E Keller, HU Sekanina, Z West, RM AF Lamy, PL Toth, I Grun, E Keller, HU Sekanina, Z West, RM TI Observations of Comet P/Faye 1991 XXI with the planetary camera of the Hubble space telescope SO ICARUS LA English DT Article ID ARAKI-ALCOCK 1983D; INNER COMA; SPECTROPHOTOMETRY; DUST AB Comet P/Faye 1991 XXI (1991 n) was observed with the planetary camera (PC) of the Hubble Space Telescope (HST) between October 29 and November 21, 1991, when its geocentric distance was in the range 0.52-0.67 AU. The resulting high resolution-a single PC pixel projected to a distance of similar to 20 km at the comet-made it possible to clearly discriminate the nucleus and to study the dust coma within similar to 100 km from the nucleus. The spherical aberration which affected the early operation of the HST has severely complicated the analysis and image restoration using the Richardson-Lucy method has failed to give satisfactory results, The coma is dominated by the point spread function (PSF) of the nucleus up to a radial distance of similar to 100 km and cannot be recovered, Beyond, it is affected by the spherical aberration up to approximately 750 km and was analyzed by comparison with a grid of models convolved with appropriate PSFs. Beyond 750 inn, it remains unaffected and can be studied directly. From the outer to the innermost regions, the coma presents an elongated shape which may be explained either by an active source on the nucleus or, more likely, by a projection effect of the dust tail, if this second interpretation is correct, then the temporal evolution of the comet is very slow and smooth, suggesting an extended source of dust on the nucleus, The dust production rate, corrected for the projection effect of the tail, amounts to 125 kg sec(-1). (C) 1996 Academic Press, Inc. C1 KONKOLY OBSERV BUDAPEST,H-1525 BUDAPEST,HUNGARY. MAX PLANCK INST KERNPHYS,D-69029 HEIDELBERG,GERMANY. MAX PLANCK INST AERON,D-37189 KATLENBURG DUHM,GERMANY. JET PROP LAB,PASADENA,CA 91109. RP Lamy, PL (reprint author), CNRS,ASTRON SPATIALE LAB,BP 8,F-13376 MARSEILLE 12,FRANCE. NR 39 TC 18 Z9 18 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 FEB PY 1996 VL 119 IS 2 BP 370 EP 384 DI 10.1006/icar.1996.0025 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TY870 UT WOS:A1996TY87000009 ER PT J AU Hamley, JA AF Hamley, JA TI Direct drive options for electric propulsion systems SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB Power processing units (PPUs) in an electric propulsion system provide many challenging integration issues. The PPU must provide power to the electric thruster while maintaining compatibility with all of the spacecraft power and data systems. Inefficiencies in the power processor produce heat, which must be radiated to the environment in order to ensure reliable operation. Although PPU efficiencies are generally greater than 0.9, heat loads are often substantial. This heat must be rejected by thermal control systems which generally have specific masses of 15 - 30 kg/kW. PPUs also represent a large fraction of the electric propulsion system dry mass. Simplification or elimination of power processing in a propulsion system would reduce the electric propulsion system specific mass and improve the overall reliability and performance. A direct drive system would eliminate all or some of the power supplies required to operate a thruster by directly connecting the various thruster loads to the solar array. The development of concentrator solar arrays has enabled power bus voltages in excess of 300 V which is high enough for direct drive applications for Hall thrusters such as the Stationary Plasma Thruster (SPT). The option of solar array direct drive for SPTs is explored to provide a comparison between conventional and direct drive system mass. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 13 TC 0 Z9 0 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD FEB PY 1996 VL 11 IS 2 BP 20 EP 24 DI 10.1109/62.484301 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA TV667 UT WOS:A1996TV66700008 ER PT J AU Wanhainen, JS Tyburski, TE AF Wanhainen, JS Tyburski, TE TI Joint US/Russian solar dynamic flight demonstration project plan SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB The United States and Russia have agreed to jointly develop a solar dynamic (SD) system for flight demonstration on the Russian orbital station, Mir, starting id late 1997. This project is funded under the International Space Station (ISS) Phase I activities which involve joint US/Russian cooperative efforts to reduce risk and enhance working relationships in preparation for the joint integration of ISS. Of the projects falling under the Phase I program, the SD Flight Demonstration (SDFD) project is most complex in terms of the level of interfacing required. This paper provides a brief description of the solar dynamic technology, the project chronology of events, the US/Russian roles on the SDFD project, the project schedule, and project management tools used in dealing with the international team. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 1 TC 0 Z9 1 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 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD FEB PY 1996 VL 11 IS 2 BP 31 EP 36 DI 10.1109/62.484303 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA TV667 UT WOS:A1996TV66700010 ER PT J AU Otoshi, TY Franco, MM AF Otoshi, TY Franco, MM TI The electrical conductivities of steel and other candidate materials for shrouds in a beam-waveguide antenna system SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB This article presents the results of electrical conductivity measurements made at 8.420 GHz on samples of the structural steel material used to fabricate shrouds on a Deep Space Network (DSN) 34-m-diameter beam-waveguide (BWG) antenna, Test results show that the structural steel samples at this microwave frequency had effective conductivities that were about 50 times worse than published de values and also 230 times worse than the measured conductivities of aluminum test samples. Conductivity data are also presented for other candidate materials that could be used to fabricate BWG shrouds. Of interest are the improvements or degradations that were observed after some of the metal test samples were surface treated, plated, or painted. RP Otoshi, TY (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 14 TC 6 Z9 6 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 77 EP 83 DI 10.1109/19.481315 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000013 ER PT J AU Froggatt, ME Allison, SG AF Froggatt, ME Allison, SG TI Interrupted ultrasonic bolt load measurements using the pulsed phase-locked loop system SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB A method of reacquiring a previous phase lock-point using the pulsed phase-locked loop (PPLL) ultrasonic system in situations where the measurement is interrupted such as by removing and recoupling the transducer is developed, Operation of the PPLL is mathematically analyzed in the time domain rather than in the conventional frequency domain, providing a method of characterizing multiple lock-points, The general lock-point reacquisition method that follows from the model relies on measurement over a frequency range that spans several lock-points and is demonstrated to work well for interrupted measurements on threaded fasteners, The method is analyzed for sensitivity to signal noise, and an equation is derived, expressing the number of lock-points over which to measure for successful lock-point reacquisition as a function of signal noise level. Experimental verification on a glass block shows that theoretical values obtained with this model are in good agreement with measurements, Automation of the method presented has been demonstrated, showing that it offers a practical, objective approach to making interrupted load measurements, thereby greatly widening the range of applications of the PPLL. RP Froggatt, ME (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 9 TC 2 Z9 2 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 112 EP 116 DI 10.1109/19.481321 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000019 ER PT J AU Froggatt, ME Allison, SG AF Froggatt, ME Allison, SG TI Pulsed phase-locked loop technology improvements for greater accuracy and expanded capabilities SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB This paper presents the design for a new pulsed phase-locked loop (PPLL) instrument. Earlier phase detection methods are analyzed for potential error sources, and an alternative phase detection method with fewer sources of error is described, This alternative method of phase detection is incorporated into a fully automated PPLL instrument, Data taken with the new system is compared to data taken with an earlier PPLL instrument, This comparison shows that the alternative phase detection does reduce error, The control loop is analyzed for stability and optimization, and a method of automating this optimization is presented, A method of wave-form acquisition using the automated PPLL that permits automatic location of the received echo is also described. RP Froggatt, ME (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 11 TC 1 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 117 EP 122 DI 10.1109/19.481322 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000020 ER PT J AU Froggatt, ME Allison, SG Moore, JP AF Froggatt, ME Allison, SG Moore, JP TI Pulsed phase-locked loop calibration over frequency SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB This paper presents a method of correcting for unwanted phase shifts introduced by interchanging ultrasonic transducers and other measurement system components when using the pulsed phase-locked loop (PPLL) ultrasonic system, Theory is derived mathematically separating phase errors into their constituents, The relationship to a previously derived method of determining the number of periods into the tone-burst, at which the system samples, is established, and a method of adjusting this number to be an integer is presented, Implementation of the technology on a computer is demonstrated through experimental results on transducers of differing frequencies and diameters, Sensitivity to path-length is tested, This work has resulted in a straightforward means of calibrating transducers in conjunction with PPLL measurements using a single, fixed reference block. RP Froggatt, ME (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 8 TC 1 Z9 1 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 123 EP 126 DI 10.1109/19.481323 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000021 ER PT J AU Doughty, DC Hodson, RF Allgood, D Bickley, M Campbell, S Putnam, T Spivak, R Lemon, S Wilson, WC AF Doughty, DC Hodson, RF Allgood, D Bickley, M Campbell, S Putnam, T Spivak, R Lemon, S Wilson, WC TI The use of content addressable memories in the LEVEL 2 trigger for the CLAS detector at CEBAF SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 9th Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics (Real-Time 95) CY MAY 23-26, 1995 CL E LANSING, MI SP Michigan State Univ, Natl Superconducting Cyclotron Lab, IEEE, NPSS, Tech Comm Comp Applicat Nucl & Plasma Sci AB The LEVEL 2 trigger in the CLAS detector will find tracks and associate a momentum and angle with each track within 2 mu s after the event. This is done through a hierarchical track finding design in which track segments are found in each drift chamber axial superlayer. An array of 384 custom content addressable (or associative) memories (CAMs) uses independent subfield matching to link these track segments into roads. The track parameters corresponding to each found road are then looked up in a separate memory. We present the overall architecture of the LEVEL 2 trigger, the details of how the CAM chip links tracks segments to find roads, and report on the performance of our prototype CAM chips. C1 CONTINUOUS ELECTRON BEAM ACCELERATOR FACIL CTR,NEWPORT NEWS,VA 23606. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP Doughty, DC (reprint author), CHRISTOPHER NEWPORT UNIV,NEWPORT NEWS,VA 23606, USA. NR 6 TC 1 Z9 1 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 111 EP 117 DI 10.1109/23.486014 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX791 UT WOS:A1996TX79100021 ER PT J AU Zwart, JW Heinen, VO Long, K Stankiewicz, N AF Zwart, JW Heinen, VO Long, K Stankiewicz, N TI Surface resistance measurements at 337 GHz SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE surface resistance; hemispherical resonator; submillimeter waves ID WAVELENGTH AB A high Q quasioptical hemispherical resonator, capable of making measurements on samples as small as 5 mm in diameter, was used to make surface resistance measurements at 337 GHz on samples of Al, Au, Mo, and Cu. Results for Al agree with the low frequency approximation, the other metals are some what higher. C1 NASA,LEWIS RES CTR,SPACE ELECTR DIV,CLEVELAND,OH 44135. RP Zwart, JW (reprint author), DORDT COLL,DEPT PHYS SCI,SIOUX CITY,IA 51250, USA. NR 9 TC 3 Z9 3 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 FEB PY 1996 VL 17 IS 2 BP 349 EP 357 DI 10.1007/BF02088157 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA TV133 UT WOS:A1996TV13300008 ER PT J AU Johnson, LF Billow, CR AF Johnson, LF Billow, CR TI Spectrometric estimation of total nitrogen concentration in Douglas-fir foliage SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID INFRARED REFLECTANCE SPECTROSCOPY; CHEMISTRY; CANOPY AB Spectral measurements of fresh and dehydrated Douglas-fir foliage, from trees cultivated under three fertilization treatments, were acquired with a laboratory spectrophotometer. The slope (first-derivative) of the fresh- and dry-leaf absorbance spectra at locations near known protein absorption features was strongly correlated with total nitrogen (TN) concentration of the foliage samples. A particularly strong correlation was observed between the first-derivative spectra in the 2150-2170 nm region and TN, reaching a local maximum in the fresh-leaf spectra of -0.84 at 2160 nm. Stepwise regression was used to generate calibration equations relating first-derivative spectra from fresh, dry/intact, and dry/ground samples to TN concentration. Standard errors of calibration were 1.52 mg g(-1) (fresh), 1.33 mg g(-1) (dry/intact), and 1.20 mg g(-1) (dry/ground), with a goodness-of-fit of 0.94 and greater. Cross-validation was performed with the fresh-leaf dataset to examine the predictive capability of the regression method; standard errors of prediction ranged from 1.47-2.37 mg g(-1) across seven different validation sets, prediction goodness of fit ranged from 0.85-0.94, and wavelength selection was fairly insensitive to the membership of the calibration set. All regressions in this study tended to select wavelengths in the 2100-2350 nm region, with the primary selection in the 2142-2172 nm region. The study provides positive evidence concerning the feasibility of assessing TN status of fresh-leaf samples by spectrometric means. We assert that the ability to extract biochemical information from fresh-leaf spectra is a necessary but insufficient condition regarding the use of remote sensing for canopy-level biochemical estimation. C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. RP Johnson, LF (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV INC,242-4,MOFFETT FIELD,CA 94035, USA. NR 22 TC 57 Z9 76 U1 0 U2 7 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 FEB PY 1996 VL 17 IS 3 BP 489 EP 500 PG 12 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA TX659 UT WOS:A1996TX65900004 ER PT J AU Otterman, J AF Otterman, J TI Desert-scrub as the cause of reduced reflectances in protected versus impacted sandy arid areas SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SURFACE ALBEDO; SATELLITE AB High contrast, commonly in the 1.3-1.5 range, was observed from satellite multi-spectral radiometers between overgrazed sandy terrain and adjacent protected (fenced-off) areas. Approximately the same contrast was reported in the visible and near-infrared spectral bands. These observations were first conducted at the border of the bright overgrazed Sinai and the darker Negev (in Israel). Extensive ground observations were carried out at this border and in the 6 km x 6 km exclosure in the northern Sinai, in which plant growth spontaneously recovered after the area was fenced off in 1974. Karnieli and Tsoar (1995) rejected the predominant role of plants in producing such contrast, concluding 'that the well-known contrast between Sinai and the Negev, that has drawn the attention of many scientists, is not a direct result of vegetation cover but is caused by an almost complete cover of biogenic crust'. This conclusion does not account for these factors: (i) the contrast between dune sand and biogenic crust measured by Karnieli and Tsoar is at most 1.25, and therefore cannot create contrasts of 1.5 observed from satellites; (ii) the dune sand to crust contrast is appreciable only above 0.6 mu m, and the satellite sensor contrast measurements include the 0.5-0.6 mu m band; and (iii) ground visual observations and published photographs show individual desert-scrub plants much darker than the soil interstices close to the observer, but at elevated view directions the plants merge, producing a nearly uniform darkening of the terrain. This limb-darkening, observed on the Israeli side along the Sinai/Negev border, is a clear indication of the strong optical effects of the plants on the terrain reflectances. RP Otterman, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 12 TC 14 Z9 15 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 FEB PY 1996 VL 17 IS 3 BP 615 EP 619 PG 5 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA TX659 UT WOS:A1996TX65900012 ER PT J AU Zak, M AF Zak, M TI Irreversibility in thermodynamics SO INTERNATIONAL JOURNAL OF THEORETICAL PHYSICS LA English DT Article AB The problem of irreversibility in thermodynamics is revisited and analyzed on the microscopic, stochastic, and macroscopic levels of description. It is demonstrated that Newtonian dynamics can be represented in the Reynolds form when each dynamical variable is decomposed into mean and fluctuation components. Additional equations coupling fluctuations and the mean values follow from the stabilization principle. The main idea of this principle is that the fluctuations must be selected from the condition that they suppress the original instability down to a neutral stability. Supplemented by the stabilization principle, the Hamiltonian or Lagrangian formalisms can describe the transition from fully reversible to irreversible motions as a result of the decomposition of chaotic motions (which are very likely to occur in many-body problems) into regular (macroscopic) motions and fluctuations. On the stochastic level of description, a new phenomenological force with non-Lipschitz properties is introduced. This force, as a resultant of a large number of collisions of a selected particle with other particles, has characteristics which are uniquely defined by the thermodynamic parameters of the process under consideration, and it represents a part of the mathematical formalism describing a random-walk-like process without invoking any probabilistic arguments. Additional non-Lipschitz thermodynamic forces are incorporated into macroscopic models of transport phenomena in order to introduce a time scale. These forces are effective only within a small domain around equilibria. Without causing any changes in other domains, they are responsible for the finite time of approaching equilibria. Such a property is very important for the interpretation of irreversibility on the macroscopic scale. RP Zak, M (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0020-7748 EI 1572-9575 J9 INT J THEOR PHYS JI Int. J. Theor. Phys. PD FEB PY 1996 VL 35 IS 2 BP 347 EP 382 DI 10.1007/BF02083821 PG 36 WC Physics, Multidisciplinary SC Physics GA TV136 UT WOS:A1996TV13600012 ER PT J AU Ou, SC Liou, KN Baum, BA AF Ou, SC Liou, KN Baum, BA TI Detection of multilayer cirrus cloud systems using AVHRR data: Verification based on FIRE II IFO composite measurements SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CLEAR-SKY; PARAMETERS; CHANNELS AB A numerical scheme has been developed to identify multilayer cirrus cloud systems using Advanced Very High Resolution Radiometer (AVHRR) data. It is based on the physical properties of the AVHRR channels 1-2 reflectance ratios, the brightness temperature differences between channels 4 and 5, and the channel 4 brightness temperatures. In this scheme, clear pixels are first separated from cloudy pixels, which are then classified into three types: cirrus, cirrus/low cloud, and low clouds. The authors have applied this scheme to the satellite data collected over the FIRE II IFO [First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment II intensive field observation] area during nine overpasses within seven observation dates. Determination of the threshold values used in the detection scheme are based on statistical analyses of these satellite data. The authors have validated the detection results against the cloudy conditions inferred from the collocated and coincident ground-based lidar and radar images, balloonborne replicator data, and National Center for Atmospheric Research CLASS (Cross-chain Loran Atmospheric Sounding System) humidity soundings on a case-by-case basis. In every case, the satellite detection results are consistent with the cloudy conditions inferred from these independent and complementary measurements. The present scheme is well suited for the detection of midlatitude, multilayer cirrus cloud systems and tropical anvils. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665. RP Ou, SC (reprint author), UNIV UTAH,DEPT METEOROL,CARSS,821 WILLIAM C BROWNING BLDG,SALT LAKE CITY,UT 84112, USA. RI Baum, Bryan/B-7670-2011 OI Baum, Bryan/0000-0002-7193-2767 NR 30 TC 22 Z9 22 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 FEB PY 1996 VL 35 IS 2 BP 178 EP 191 DI 10.1175/1520-0450(1996)035<0178:DOMCCS>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB909 UT WOS:A1996UB90900003 ER PT J AU Haddad, ZS Im, E Durden, SL AF Haddad, ZS Im, E Durden, SL TI Optimal estimation of rain-rate profiles from single-frequency radar echoes SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ATTENUATION AB The significant ambiguities inherent in the determination of a particular vertical rain intensity profile from a given time profile of radar echo powers measured by a downward-looking (spaceborne or airborne) radar at a single attenuating frequency are well documented. Indeed, one already knows that by appropriately varying the parameters of the reflectivity-rain rate (Z-R) and/or attenuation-rain rate (k-R) relationships one can produce several substantially different rain-rate profiles that would produce the same radar power profile. Imposing the additional constraint that the path-averaged rain rate be a given fixed number does reduce the ambiguities but falls far short of eliminating them. While formulas to generate all mutually ambiguous rain-rate profiles from a given profile of received radar reflectivities have already been derived, there remains to be produced a quantitative measure to assess how likely each of these profiles is, what the appropriate ''average'' profile should be, and what the ''variance'' of these multiple solutions is. To do this, one needs to spell out the stochastic constraints that can allow us to make sense of the words ''average'' and ''variance'' in a mathematically rigorous way. Such a quantitative approach would be particularly well suited for such systems as the planned precipitation radar of the Tropical Rainfall Measuring Mission (TRMM). Indeed, one would then be able to use the radar reflectivities measured by the TRMM radar to estimate the rain-rate profile that would most likely have produced the measurements, as well as the uncertainty in the estimated rain rates as a function of range. Such an optimal approach is described in this paper. RP Haddad, ZS (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 13 TC 6 Z9 6 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 1996 VL 35 IS 2 BP 214 EP 228 DI 10.1175/1520-0450(1996)035<0214:OEORRP>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB909 UT WOS:A1996UB90900006 ER PT J AU Haddad, ZS Im, E Durden, SL Hensley, S AF Haddad, ZS Im, E Durden, SL Hensley, S TI Stochastic filtering of rain profiles using radar, surface-referenced radar, or combined radar-radiometer measurements SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB This paper describes a computationally efficient nearly optimal Bayesian algorithm to estimate rain (and drop size distribution) profiles, given a radar reflectivity profile at a single attenuating wavelength. In addition to estimating the averages of all the mutually ambiguous combinations of rain parameters that can produce the data observed, the approach also calculates the rms uncertainty in its estimates (this uncertainty thus quantifies the ''amount of ambiguity'' in the ''solution''). The paper also describes a more general approach that can make estimates based on a radar reflectivity profile together with an approximate measurement of the path-integrated attenuation, or a radar reflectivity profile and a set of passive microwave brightness temperatures. This more general ''combined'' algorithm is currently being adapted for the Tropical Rainfall Measuring Mission. RP Haddad, ZS (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 12 TC 15 Z9 15 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 1996 VL 35 IS 2 BP 229 EP 242 DI 10.1175/1520-0450(1996)035<0229:SFORPU>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB909 UT WOS:A1996UB90900007 ER PT J AU Jameson, AR Durden, SL AF Jameson, AR Durden, SL TI A possible origin of linear depolarization observed at vertical incidence in rain SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID POLARIZATION MEASUREMENTS; RADAR; PRECIPITATION; RAINDROPS; RATIOS AB Recent observations by two different nadir-pointing airborne radars with some polarization capabilities have detected surprisingly large linear depolarization ratios at times in convective tropical rain. This depolarization can be explained if the rain is considered to be a mixture of a group of apparent spheres and another group of drops that are distorted in the horizontal plane perpendicular to the direction of propagation of the incident wave. If confirmed in future observations, this suggests that at times the larger raindrops are oscillating, in part, because of collisions with smaller drops. Since many of the interpretations of radar polarization measurements in rain by ground-based radars presume that the raindrop shapes correspond to those of the well-known ''equilibrium'' drops, the present observations may require adjustments to some radar polarization algorithms for estimating rainfall rate, for example, if the shape perturbations observed at nadir also apply to measurements along other axes as well. C1 APPL RES CORP,LANDOVER,MD 20785. CALTECH,JET PROP LAB,PASADENA,CA. NR 25 TC 9 Z9 9 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 FEB PY 1996 VL 35 IS 2 BP 271 EP 277 DI 10.1175/1520-0450(1996)035<0271:APOOLD>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB909 UT WOS:A1996UB90900010 ER PT J AU Dessler, AE Minschwaner, K Weinstock, EM Hintsa, EJ Anderson, JG Russell, JM AF Dessler, AE Minschwaner, K Weinstock, EM Hintsa, EJ Anderson, JG Russell, JM TI The effects of tropical cirrus clouds on the abundance of lower stratospheric ozone SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE cirrus clouds; heating rates; tropics; lower stratospheric ozone ID TWO-DIMENSIONAL MODEL; RADIATIVE BALANCE; WATER CLOUDS; ABSORPTION; PROFILES AB The distribution of many chemical constituents of the atmosphere (e.g., ozone) is at least partially determined by the distribution of net radiative heating in the atmosphere. In this paper, we demonstrate the significant effect of high cirrus clouds on the net radiative heating of the tropical lower stratosphere. A model of tropical lower stratospheric ozone is then used to demonstrate the sensitivity of calculated ozone to the varying cloud cover used in the model. We conclude that calculated ozone is sensitive to the inclusion of clouds in models and that models of the atmosphere should include a realistic description of tropical cirrus clouds in order to accurately simulate the chemical composition of the atmosphere. C1 NEW MEXICO INST MIN & TECHNOL,DEPT PHYS,SOCORRO,NM 87801. HARVARD UNIV,ATMOSPHER RES PROJECT,CAMBRIDGE,MA 02138. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP Dessler, AE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 27 TC 21 Z9 21 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD FEB PY 1996 VL 23 IS 2 BP 209 EP 220 DI 10.1007/BF00048261 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA TZ503 UT WOS:A1996TZ50300005 ER PT J AU Back, LH Kwack, EY Back, MR AF Back, LH Kwack, EY Back, MR TI Flow rate pressure drop relation in coronary angioplasty: Catheter obstruction effect SO JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID STEADY FLOW; ARTERY; GRADIENT; HUMANS; STENOSES AB Quantitative methods to measure the hemodynamic consequences of various endovascular interventions including balloon angioplasty are limited. Catheters measuring translesional pressure drops during balloon angioplasty procedures can cause flow blockage and thus inaccurate estimates of pre- and post-intervention flow rates. The purpose of this investigation was to examine the influence of the presence and size of an angioplasty catheter on measured mean pressure gradients across human coronary artery stenoses. Analytical flow modeling and in vitro experimental evidence, coupled with angiographic data on the dimensions and shape of stenotic vessel segments before and after angioplasty, indicated significant flow blockage effects with the catheter present. C1 UNIV CALIF LOS ANGELES,HARBOR MED CTR,DEPT SURG,TORRANCE,CA 90509. RP Back, LH (reprint author), CALTECH,JET PROPULS LAB,PASADENA,CA 91109, USA. NR 21 TC 43 Z9 44 U1 0 U2 5 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0148-0731 J9 J BIOMECH ENG-T ASME JI J. Biomech. Eng.-Trans. ASME PD FEB PY 1996 VL 118 IS 1 BP 83 EP 89 DI 10.1115/1.2795949 PG 7 WC Biophysics; Engineering, Biomedical SC Biophysics; Engineering GA TY355 UT WOS:A1996TY35500011 PM 8833078 ER PT J AU DelGenio, AD Yao, MS Kovari, W Lo, KKW AF DelGenio, AD Yao, MS Kovari, W Lo, KKW TI A prognostic cloud water parameterization for global climate models SO JOURNAL OF CLIMATE LA English DT Article ID TOP ENTRAINMENT INSTABILITY; GENERAL-CIRCULATION MODELS; MARINE STRATOCUMULUS; OPTICAL-PROPERTIES; STRATIFORM CLOUDS; CIRRUS CLOUDS; FEEDBACK; SATELLITE; SCHEME; CONDENSATION AB An efficient new prognostic cloud water parameterization designed for use in global climate models is described. The scheme allows for life cycle effects in stratiform clouds and permits cloud optical properties to be determined interactively. The parameterization contains representations of all important microphysical processes, including autoconversion, accretion, Bergeron-Findeisen diffusional growth, and cloud/rain water evaporation. Small-scale dynamical processes, including detrainment of convective condensate, cloud-top entrainment instability, and stability-dependent cloud physical thickness variations, are also taken into account. Cloud optical thickness is calculated from the predicted Iiquid/ice water path and a variable droplet effective radius estimated by assuming constant droplet number concentration. Microphysical and radiative properties are assumed to be different for liquid and ice clouds, and for liquid clouds over land and ocean. The parameterization is validated in several simulations using the Goddard Institute for Space Studies (GISS) general circulation model (GCM). Comparisons are made with a variety of datasets, including ERBE radiative fluxes and cloud forcing, ISCCP and surface-observed cloud properties, SSM/I liquid water path, and SAGE II thin cirrus cover. Validation is judged on the basis of the model's depiction of both the mean state; diurnal, seasonal, and interannual variability; and the temperature dependence of cloud properties. Relative to the diagnostic cloud scheme used in the previous GISS GCM, the prognostic parameterization strengthens the model's hydrologic cycle and general circulation, both directly and indirectly (via increased cumulus heating). Sea surface temperature (SST) perturbation experiments produce low climate sensitivity and slightly negative cloud feedback for globally uniform SST changes, but high sensitivity and positive cloud feedback when tropical Pacific SST gradients weaken with warming. Changes in the extent and optical thickness of tropical cumulus anvils appear to be the primary factor determining the sensitivity. This suggests that correct simulations of upward transport of convective condensate and of Walker circulation changes are of the highest priority for a realistic estimate of cloud feedback in actual greenhouse gas increase scenarios. C1 SCI SYST & APPL INC,INST SPACE STUDIES,NEW YORK,NY. RP DelGenio, AD (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Del Genio, Anthony/D-4663-2012 OI Del Genio, Anthony/0000-0001-7450-1359 NR 68 TC 310 Z9 310 U1 0 U2 19 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 1996 VL 9 IS 2 BP 270 EP 304 DI 10.1175/1520-0442(1996)009<0270:APCWPF>2.0.CO;2 PG 35 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB900 UT WOS:A1996UB90000003 ER PT J AU Foster, J Liston, G Koster, R Essery, R Behr, H Dumenil, L Verseghy, D Thompson, S Pollard, D Cohen, J AF Foster, J Liston, G Koster, R Essery, R Behr, H Dumenil, L Verseghy, D Thompson, S Pollard, D Cohen, J TI Snow cover and snow mass intercomparisons of general circulation models and remotely sensed datasets SO JOURNAL OF CLIMATE LA English DT Article ID BIOSPHERE MODEL; SURFACE ALBEDO; CLIMATE; VEGETATION AB Confirmation of the ability of general circulation models (GCMs) to accurately represent snow cover and snow mass distributions is vital for climate studies. There must be a high degree of confidence that what is being predicted by the models is reliable, since realistic results cannot be assured unless they are tested against results from observed data or other available datasets. In this study, snow output from seven GCMs and passive microwave snow data derived from the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) are intercompared. National Oceanic and Atmospheric Administration satellite data are used as the standard of reference for snow extent observations and the U.S. Air Force snow depth climatology is used as the standard for snow mass. The reliability of the SMMR snow data needs to be verified, as well, because currently this is the only available dataset that allows for yearly and monthly variations in snow depth. [The GCMs employed in this investigation are the United Kingdom Meteorological Office, Hadley Centre GCM, the Max Planck Institute for Meteorology/University of Hamburg (ECHAM) GCM, the Canadian Climate Centre GCM, the National Center for Atmospheric Research (GENESIS) GCM, the Goddard Institute for Space Studies GCM, the Goddard Laboratory for Atmospheres GCM and the Goddard Coupled Climate Dynamics Group (AIRES) GCM.] Data for both North America and Eurasia are examined in an effort to assess the magnitude of spatial and temporal variations that exist between the standards of reference, the models, and the passive microwave data. Results indicate that both the models and SMMR represent seasonal and year-to-year snow distributions fairly well. The passive microwave data and several of the models, however, consistently underestimate snow mass, but other models overestimate the mass of snow on the ground. The models do a better job simulating winter arid summer snow conditions than in the transition months. In general,the underestimation by SMMR is caused by absorption of microwave energy by vegetation. For the GCMs, differences between observed snow conditions can be ascribed to inaccuracies in simulating surface air temperatures and precipitation fields, especially during the spring and fall. C1 UNITED KINGDOM METEOROL OFF, HADLEY CLIMATE CTR, BRACKNELL, BERKS, ENGLAND. UNIV HAMBURG, INST METEOROL, W-2000 HAMBURG, GERMANY. CANADIAN CLIMATE CTR, ATMOSPHER ENVIRONM SERV, DOWNSVIEW, ON, CANADA. NATL CTR ATMOSPHER RES, INTERDISCIPLINARY CLIMATE SYST, BOULDER, CO 80307 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP Foster, J (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HYDROL SCI BRANCH, GREENBELT, MD 20771 USA. RI Koster, Randal/F-5881-2012; OI Koster, Randal/0000-0001-6418-6383; Essery, Richard/0000-0003-1756-9095 NR 34 TC 101 Z9 107 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 1996 VL 9 IS 2 BP 409 EP 426 DI 10.1175/1520-0442(1996)009<0409:SCASMI>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB900 UT WOS:A1996UB90000010 ER PT J AU Khamayseh, A Mastin, CW AF Khamayseh, A Mastin, CW TI Computational conformal mapping for surface grid generation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article AB The paper describes the development and application of a new approach for formulating an elliptic generation system on parametrically defined surfaces. The present derivation of the surface equations proceeds in two steps: First, conformal mapping of smooth surfaces onto rectangular regions is utilized to derive a first-order system of partial differential equations analogous to Beltrami's system for quasi-conformal mapping of planar regions. Second, a general elliptic generation system for three-dimensional surfaces, including forcing functions, is formulated based on Beltrami's system and quasi-conformal mapping. The resulting elliptic system is solved using an iterative method on arbitrary surfaces represented analytically by rational B-splines. The overall effect of this approach is a reliable and versatile elliptic method for generating and improving surface grids. Examples will be presented to demonstrate the application of the method in constructing practical grids. (C) 1996 Academic Press, Inc. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RP Khamayseh, A (reprint author), LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 21 TC 17 Z9 17 U1 0 U2 1 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 FEB PY 1996 VL 123 IS 2 BP 394 EP 401 DI 10.1006/jcph.1996.0032 PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA TU992 UT WOS:A1996TU99200012 ER PT J AU Gasparini, DA Bonacuse, P Powers, L Romeo, A AF Gasparini, DA Bonacuse, P Powers, L Romeo, A TI Stochastic parallel-brittle networks for modeling materials SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID BUNDLES PROBABILITY MODEL; FIBROUS MATERIALS; COMPOSITES; ALGORITHMS; FRACTURE; STRENGTH; MESHES AB The behavior of Voronoi-Delaunay parallel-brittle networks of truss elements as models for material behavior is studied. Means and variances of both the number of elements in a network and their length are given. The uniaxial stiffness of the networks is found equal to the element axial stiffness. The expected value of the network's uniaxial-tensile strength is proportional to the square root of the expected number of elements and to the expected value of the strength of the elements. The toughness of the networks is proportional to the square of the expected value of element strength and to the square root of the expected number of elements. An application to pullout of an anchor is presented. Daniels systems and chain-of-bundles systems are also analyzed to provide perspective. Statistical size effects for parallel-brittle networks are quite different form those associated with weak-link systems. C1 NASA,LEWIS RES CTR,ARMY RES LAB,CLEVELAND,OH 44135. CLEVELAND STATE UNIV,DEPT CIVIL ENGN,CLEVELAND,OH 44115. CASE WESTERN RESERVE UNIV,DEPT CIVIL ENGN,CLEVELAND,OH 44106. RP Gasparini, DA (reprint author), CASE WESTERN RESERVE UNIV,DEPT CIVIL ENGN,CLEVELAND,OH 44106, USA. NR 23 TC 2 Z9 2 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD FEB PY 1996 VL 122 IS 2 BP 130 EP 137 DI 10.1061/(ASCE)0733-9399(1996)122:2(130) PG 8 WC Engineering, Mechanical SC Engineering GA TR922 UT WOS:A1996TR92200007 ER PT J AU Mattikalli, NM AF Mattikalli, NM TI Time series analysis of historical surface water quality data of the River Glen catchment, UK SO JOURNAL OF ENVIRONMENTAL MANAGEMENT LA English DT Article DE surface water quality; total oxidized nitrogen; time series analysis; regression analysis ID NITRATE AB Solute concentrations in surface waters have increased in the recent past in many developed countries, and are close to or above WHO and EC drinking water limits in many British rivers. A time series analysis of surface water quality as indexed by total oxidized nitrogen (TON) is carried out for the River Glen catchment, U.K. for the period 1976-1990. Significant seasonal trends are observed in water quality, with solute concentrations increasing during winter and decreasing in summer. In addition, a strong increasing trend is observed in the nitrogen records using both graphical outputs and statistical analysis. Standard time series analyses (auto-correlation and partial auto-correlation functions) are not applicable to irregularly sampled water quality data sets provided by river monitoring public/statutory bodies, and there is a need for an established method capable of handling such data sets that would be available for most rivers. An approach based on multiple regression analysis has therefore been developed to quantify both seasonal and annual trends in the TON water quality data. It has been demonstrated that this approach is useful for the analysis of historical water quality data sets. (C) 1996 Academic Press Limited RP Mattikalli, NM (reprint author), NASA, GODDARD SPACE FLIGHT CTR, LAB HYDROSPHER PROC, HYDROL SCI BRANCH, CODE 974, GREENBELT, MD 20771 USA. NR 16 TC 12 Z9 12 U1 2 U2 6 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0301-4797 EI 1095-8630 J9 J ENVIRON MANAGE JI J. Environ. Manage. PD FEB PY 1996 VL 46 IS 2 BP 149 EP 172 DI 10.1006/jema.1996.0013 PG 24 WC Environmental Sciences SC Environmental Sciences & Ecology GA TU753 UT WOS:A1996TU75300004 ER PT J AU Cole, KD Hoegy, WR AF Cole, KD Hoegy, WR TI Joule heating by ac electric fields in the ionosphere of Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PIONEER VENUS AB It is shown that Joule heating from electron collision damping of ac electric fields could be a significant source of energy for electrons in the Venus ionosphere if they occur naturally on a large scale. On the assumption that the fields are due to electromagnetic waves on a planetary scale, we calculate heating rates implied by observations on the dayside and compare them with the profiles of photoelectron heating rates used by modelers. It is found that sufficient amplitudes have been measured on Pioneer Venus Orbiter in the frequency Channels of 730 and 100 Hz to cause greater local electron heating rates than that due to photoelectrons, up to 3 orders of magnitude in some cases. Nightside heating rates at low altitudes for the 100-Hz signal would cause great heating of the ionosphere and thermosphere, airglow, and aurora. The difficulties produced by these findings would be relieved if die electric field disturbances were closely confined to the spacecraft or at least were much less than planetary in scale. RP Cole, KD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 910-4,GREENBELT,MD 20771, USA. NR 20 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 JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1996 VL 101 IS A2 BP 2269 EP 2278 DI 10.1029/95JA01853 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT923 UT WOS:A1996TT92300001 ER PT J AU Crooker, NU Burton, ME Phillips, JL Smith, EJ Balogh, A AF Crooker, NU Burton, ME Phillips, JL Smith, EJ Balogh, A TI Heliospheric plasma sheets as small-scale transients SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLANAR MAGNETIC-STRUCTURES; HEAT-FLUX DROPOUTS; PLANETARY SECTOR BOUNDARIES; CORONAL MASS EJECTA; SOLAR-WIND; CLOUDS; 1-AU; FIELDS AB Ulysses plasma and magnetic field data from the ecliptic plane near 1 AU signaling multiple heliospheric plasma sheets across a sector boundary are analyzed in order to determine their geometrical configuration. The plasma sheets coincided with a region of sporadic heat flux dropouts and planar magnetic structure. The plane of the structure was inclined to the ecliptic plane by 56 degrees and nearly orthogonal to the Parker spiral. Pronounced flow deflections within the plasma sheets were closely aligned with the magnetic structure plane. Geometrical constraints and the lack of correlation between the highly variable magnetic fields in the planar structure and the flow deflections preclude a single, wavy plasma sheet interpretation. The flow deflections were nested in similar, larger-scale deflections on the downslope of a pressure wave. The observations are consistent with spacecraft passage through the flanks of a transient disturbance which distorted the sector boundary plane. We interpret the planar magnetic structure with its embedded plasma sheets as a layer of small-scale, intertwined flux ropes with varying degrees of helicity, flattened into sector-boundary-aligned sheets by kinematic distention and compression. The sporadic dropout of heat flux may have signaled flux-rope detachment from the Sun or particle scattering, possibly owing to the high variability of plasma parameters across the plasma sheets. C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. CALTECH,JET PROPULS LAB,MS 169506,PASADENA,CA 91109. LOS ALAMOS NATL LAB,MS D466,LOS ALAMOS,NM 87545. RP Crooker, NU (reprint author), BOSTON UNIV,CTR SPACE PHYS,725 COMMONWEALTH AVE,BOSTON,MA 02215, USA. NR 37 TC 42 Z9 43 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 FEB 1 PY 1996 VL 101 IS A2 BP 2467 EP 2474 DI 10.1029/95JA03148 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT923 UT WOS:A1996TT92300017 ER PT J AU Ghosh, S Siregar, E Roberts, DA Goldstein, ML AF Ghosh, S Siregar, E Roberts, DA Goldstein, ML TI Simulation of high-frequency solar wind power spectra using Hall magnetohydrodynamics SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DISPERSIVE ALFVEN WAVES; PARAMETRIC-INSTABILITIES; MAGNETIC-FIELD; RADIAL EVOLUTION; MHD TURBULENCE; FLUCTUATIONS; DEPENDENCE; RELAXATION; EXCITATION; HELICITY AB Solar wind frequency spectra show a distinct steepening of the f(-5/3) power law inertial range spectrum at frequencies above the Doppler-shifted ion cyclotron frequency. This is commonly attributed to dissipation due to wave-particle interactions. We consider the extent to which this steepening can be described, using a magnetohydrodynamic formulation that includes the Hall term. An important characteristic of Hall MHD is that although the ion cyclotron resonance is included, there is no wave-particle dissipation of energy. In this study we use a compressible Hall MHD code with a constant magnetic field and a polytropic equation of state. Artificial dissipation in the form of a bi-laplacian operator is used to suppress numerical instabilities, allowing for a clear separation of the dissipative scales from the ion cyclotron scales. A distinct steepening appears in the simulation power spectra near the cyclotron resonance for certain types of initial conditions. This steepening is associated with the appearance of right circularly polarized fluctuations at frequencies above the ion cyclotron resonance. Similar steepenings and polarization enhancements are observed in solar wind magnetic field data. C1 NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, GREENBELT, MD 20771 USA. RP Ghosh, S (reprint author), APPL RES CORP, 8201 CORP DR, LANDOVER, MD 20785 USA. RI Roberts, Dana/D-4625-2012; Goldstein, Melvyn/B-1724-2008 NR 30 TC 96 Z9 96 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 FEB 1 PY 1996 VL 101 IS A2 BP 2493 EP 2504 DI 10.1029/95JA03201 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT923 UT WOS:A1996TT92300020 ER PT J AU Richardson, IG Owen, CJ Slavin, JA AF Richardson, IG Owen, CJ Slavin, JA TI Energetic (>0.2 MeV) electron bursts in the deep geomagnetic tail observed by the Goddard Space Flight Center experiment on ISEE 3: Association with geomagnetic substorms SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TRAVELING COMPRESSION REGIONS; EARTHS BOW SHOCK; DISTANT MAGNETOTAIL; MAGNETIC-FIELD; ION BURSTS; PLASMA; GEOTAIL; AVERAGE; RE; ANISOTROPIES AB Brief (<1-hour duration) 0.2- to 2-MeV electron bursts were detected in the geomagnetic tail out to 238 R(E) from Earth by the Goddard Space might Center medium energy cosmic ray experiment on ISEE 3 in 1982-1983. We examine their association with geomagnetic substorms and illustrate several examples in conjunction with simultaneous ISEE 3 plasma, magnetic field, and low-energy (35-56 keV) ion data. The majority (>80%) of electron bursts in the plasma sheet and plasma sheet boundary layer (PSBL) were associated with AL intensifications and/or particle injections observed at geosynchronous orbit, indicative of a relationship with substorm onsets. Bursts were detected following less than 50% of apparent substorms, presumably because a burst was detected only if the spacecraft was located within the region of field lines reconnected at the substorm neutral line. In the deep tail (similar to 200 R(E) from Earth), peak energetic electron intensities were typically observed near the outer edge of the PSBL closely following substorm onset. This finding suggests that the electrons were accelerated on newly reconnected field lines and lost rapidly from the tail. Unlike low-energy (tens of keV) ions, energetic electrons (at least with intensities above the detector background) were not a general feature of the PSBL or the plasma sheet outside times of enhanced substorm activity. Most plasmoids (similar to 80%) in the deep tail were not associated with enhanced energetic electron fluxes, a suggestion that electrons accelerated at the substorm neutral line during disconnection of the plasmoid may leak out from the plasmoid. This possibility is consistent with flux-rope-like magnetic Structures in plasmoids which connect to open field lines at the flanks of the tail. Electron anisotropies can be examined during the more intense bursts. These show either weak flows consistent with trapping on closed field lines connected to the Earth or stronger, tailward flows which suggest flow away from an acceleration region earthward of the spacecraft. Weak flows were observed in the plasma sheet within similar to 90 R(E) from Earth, consistent with previous ISEE 3 studies suggesting that this is the typical location of the distant neutral line. We confirm earlier observations that electron bursts in the magnetosheath are found predominantly close to the magnetopause, are associated with low-energy ion enhancements, and show strong tailward flows. Since most of these bursts were detected within similar to 90 R(E) of Earth, the region where intense plasma sheet electron bursts were also observed, this finding suggests that the plasma sheet may be source of the magnetosheath bursts. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. HUGHES STX CORP,LANHAM,MD. RP Richardson, IG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 661,GREENBELT,MD 20771, USA. RI Owen, Christopher/C-2999-2008; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Slavin, James/0000-0002-9206-724X NR 64 TC 8 Z9 8 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 FEB 1 PY 1996 VL 101 IS A2 BP 2723 EP 2740 DI 10.1029/95JA03375 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT923 UT WOS:A1996TT92300044 ER PT J AU Bhattacharjee, S Altenkirch, RA Sacksteder, K AF Bhattacharjee, S Altenkirch, RA Sacksteder, K TI Effect of ambient pressure on flame spread over thin cellulosic fuel in a quiescent, microgravity environment SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE combustion; microgravity heat transfer; radiation AB Results from recently conducted experiments on flame spread over a thin cellulosic fuel in a quiescent, microgravity environment of a 50/50 volumetric mixture of oxygen and nitrogen (oxygen mass fraction 0.53) at three different pressures-101, 152, and 203 kPa (1, 1.5, and 2.0 atm)-are analyzed. The results are compared with established theoretical results and two different computational flame spread models. one that includes gas-phase radiation, and one that does not. The spread rate behavior from experiment, i.e., an increase of spread rate with pressure, is consistent with the theoretical model that includes gas-phase radiation, and side-view photographs of the flames compare favorably with two-dimensional temperature contours produced computationally from the same model. In contrast, neither the dependence of spread rate on pressure nor the flame shape can be predicted with favorable comparison to experiment if radiation is neglected. C1 MISSISSIPPI STATE UNIV,DEPT MECH ENGN,MISSISSIPPI STATE,MS 39762. MISSISSIPPI STATE UNIV,NSF ENGN RES CTR COMPUTAT FIELD SIMULAT,MISSISSIPPI STATE,MS 39762. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Bhattacharjee, S (reprint author), SAN DIEGO STATE UNIV,DEPT MECH ENGN,SAN DIEGO,CA 92182, USA. NR 17 TC 18 Z9 19 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 FEB PY 1996 VL 118 IS 1 BP 181 EP 190 DI 10.1115/1.2824032 PG 10 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA TZ963 UT WOS:A1996TZ96300024 ER PT J AU Spuckler, CM Siegel, R AF Spuckler, CM Siegel, R TI Two-flux and diffusion methods for radiative transfer in composite layers SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE radiation; radiation interactions C1 NASA,LEWIS RES CTR,RES ACAD,CLEVELAND,OH 44135. RP Spuckler, CM (reprint author), NASA,LEWIS RES CTR,INTERNAL FLUID MECH DIV,CLEVELAND,OH 44135, USA. NR 8 TC 8 Z9 9 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 FEB PY 1996 VL 118 IS 1 BP 218 EP 222 DI 10.1115/1.2824043 PG 5 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA TZ963 UT WOS:A1996TZ96300033 ER PT J AU Schmitt, DA Schaffar, L Taylor, GR Loftin, KC Schneider, VS Koebel, A Abbal, M Sonnenfeld, G Lewis, DE Reuben, JR Ferebee, R AF Schmitt, DA Schaffar, L Taylor, GR Loftin, KC Schneider, VS Koebel, A Abbal, M Sonnenfeld, G Lewis, DE Reuben, JR Ferebee, R TI Use of bed rest and head-down tilt to simulate spaceflight-induced immune system changes SO JOURNAL OF INTERFERON AND CYTOKINE RESEARCH LA English DT Article ID SANDWICH ENZYME-IMMUNOASSAY; BONE-RESORPTION; INTERLEUKIN-1; LEVEL; MICROGRAVITY; STIMULATION; INTERFERON; MECHANISM; HORMONES; INVIVO AB Bed rest, both with and without head-down tilt, has been extensively used as an earth-bound analog to study physiologic effects mimicking those occurring in weightlessness during spaceflight. We have been able to show in six subjects that 4 weeks of head-down tilt bed rest induces a significant decrease in interleukin-2 secretion by PHA-stimulated T lymphocytes, Another study, lasting 113 days, with two subjects showed a decreased interleukin-2 receptor expression in PHA-stimulated peripheral blood mononuclear cells but a decreased interleukin-2 production in one subject only, Under the same conditions, interleukin-1 production was largely increased in both subjects. Several other immune parameters were also analyzed, Increased interleukin-1 production could contribute to bone mineral loss encountered during bed rest and decreased interleukin-2 secretion could play a role in the appearance of infectious diseases often observed during bed red. C1 FAC MED, IMMUNOL LAB, TOULOUSE, FRANCE. FAC MED, INSERM U210, NICE, FRANCE. NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. KRUG LIFE SCI, HOUSTON, TX USA. NASA HEADQUARTERS, WASHINGTON, DC USA. UNIV LOUISVILLE, DEPT MICROBIOL & IMMUNOL, LOUISVILLE, KY 40292 USA. CAROLINAS MED CTR, DEPT GEN SURG RES, CHARLOTTE, NC 28203 USA. BAYLOR COLL MED, DEPT MICROBIOL & IMMUNOL, HOUSTON, TX 77030 USA. UNIV TEXAS, MD ANDERSON CANC CTR, TRANSFUS MED & LAB IMMUNOL, HOUSTON, TX USA. UNIV HOUSTON CLEAR LAKE, SCH NAT & APPL SCI, HOUSTON, TX 77058 USA. RP Schmitt, DA (reprint author), CHU RANGUEIL, IMMUNOL LAB, F-31054 TOULOUSE, FRANCE. NR 40 TC 29 Z9 29 U1 2 U2 5 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1079-9907 J9 J INTERF CYTOK RES JI J. Interferon Cytokine Res. PD FEB PY 1996 VL 16 IS 2 BP 151 EP 157 DI 10.1089/jir.1996.16.151 PG 7 WC Biochemistry & Molecular Biology; Cell Biology; Immunology SC Biochemistry & Molecular Biology; Cell Biology; Immunology GA TW052 UT WOS:A1996TW05200008 PM 8742368 ER PT J AU Pearson, JC Sastry, KVLN Herbst, E DeLucia, FC AF Pearson, JC Sastry, KVLN Herbst, E DeLucia, FC TI The millimeter- and submillimeter-wave spectrum of gauche-ethyl alcohol SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ASYMMETRIC ASYMMETRIC MOLECULES; INTERNAL-ROTATION PROBLEM; MICROWAVE DETECTION; AXIS APPROACH; CH2DOH; TRANSITIONS; CHD2OH; TRANS AB We report an investigation of the rotational-torsional spectrum of the gauche rotational isomers of ethyl alcohol in the 51-505 GHz frequency region. Over a thousand transitions between rotational levels in the gauche substates of the ground OH torsional state have been measured and assigned. These transitions involve rotational quantum numbers J and K-a up to 30 and 15, respectively, and are of two types: a-type transitions between levels in either the gauche+ or the gauche- substate, and c-type transitions between rotational levels in the different substates, The majority of these transitions have been fit satisfactorily using a two-state Hamiltonian based on the fixed framework axis method (FFAM). The rotation, distortion, and interaction constants have been determined along with the energy difference between the two gauche substates, The derived constants can be used to predict many more transitions accurately for astronomical purposes. The J and K-a region where the two-state analysis can be used has been determined. The basis for a three-state analysis including the trans substate is presented and the applicability of the FFAM approach is discussed. (C) 1996 Academic Press, Inc. C1 UNIV NEW BRUNSWICK,DEPT PHYS,FREDERICTON,NB E3B 5A3,CANADA. OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. RP Pearson, JC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 183-301,PASADENA,CA 91109, USA. NR 36 TC 50 Z9 50 U1 0 U2 5 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 FEB PY 1996 VL 175 IS 2 BP 246 EP 261 DI 10.1006/jmsp.1996.0030 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA TZ884 UT WOS:A1996TZ88400005 ER PT J AU Huebner, WP Bloomberg, JJ AF Huebner, WP Bloomberg, JJ TI A system for the accurate measurement of pointing responses SO JOURNAL OF NEUROSCIENCE METHODS LA English DT Article DE pointing; measurement system; laser; projection display ID MOVEMENTS AB We present an accurate, yet relatively inexpensive, system for measuring the direction of pointing responses. This system utilizes off-the-shelf business presentation components in a novel way to help detect and quantify the pointing measurements. The system configuration, measurement features, and procedures to enhance measurement accuracy are described. C1 NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,HOUSTON,TX 77058. RP Huebner, WP (reprint author), KRUG LIFE SCI INC,NEUROSCI LAB,1290 HERCULES,SUITE 120,HOUSTON,TX 77058, USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-0270 J9 J NEUROSCI METH JI J. Neurosci. Methods PD FEB PY 1996 VL 64 IS 2 BP 233 EP 236 DI 10.1016/0165-0270(95)00098-4 PG 4 WC Biochemical Research Methods; Neurosciences SC Biochemistry & Molecular Biology; Neurosciences & Neurology GA UB260 UT WOS:A1996UB26000012 PM 8699885 ER PT J AU Chellaiah, S Singh, H AF Chellaiah, S Singh, H TI Freezing of a salt solution in a packed bed SO JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID SOLIDIFICATION AB There are many natural processes and technological applications that involve the solidification of a binary solution saturating a porous matrix. Some of them are. natural freezing and artificial freezing (for construction purposes) of soil, oil exploration in cold regions, and processing and preservation of food. This paper presents the results of a fundamental study of freezing of a binary salt solution saturating a packed bed An aqueous sodium chloride solution (of noneutectic composition) constituted the binary solution and spherical glass bends constituted the packed bed. The freezing was initiated at one of the vertical walls of a rectangular cavity.;v. The temperature distributions in the solid mush, and liquid regions were recorded using thermocouples. The concentration of salt was determined using a sample withdrawal technique in conjunction with a refractometer and a calibration chart. There was buoyancy-driven convective flow generated and sustained by the thermal and solutal gradients. The effect of this flow on the freezing process was significant. The morphology of the freezing fronts, the temperature and salt concentration profiles, and the rate of freezing were all influenced by the flow. Even in experiments with an initial superheat of 10 degrees C, it was found that the effect of flow was considerable. For even though the fluid flows through the interstitial spaces in the porous matrix, the permeability was large for balls of 0.5-in. diameter. With a superheat of 20 degrees C, the convection was vigorous and the rate of freezing was retarded considerably. The salt rejected during freezing was redistributed by the flow. At later times, a stable solute-rich region formed at the bottom of test cell where the concentration decreased with height. The amount of salt rejected was directly influenced by the rate of freezing, which in turn was controlled by the superheat and the permeability of packed bed. C1 EQUIFAX SPECIALTIES INC,MIAMI,FL 33169. RP Chellaiah, S (reprint author), NASA,LEWIS RES CTR,MAIL STOP 105-1,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 20 TC 1 Z9 1 U1 1 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0892-7219 J9 J OFFSHORE MECH ARCT JI J. Offshore Mech. Arct. Eng. Trans. ASME PD FEB PY 1996 VL 118 IS 1 BP 79 EP 85 DI 10.1115/1.2828805 PG 7 WC Engineering, Ocean; Engineering, Mechanical SC Engineering GA TX654 UT WOS:A1996TX65400011 ER PT J AU Panontin, TL Hill, MR AF Panontin, TL Hill, MR TI Proof-test-based life prediction of high-toughness pressure vessels SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article AB The paper examines the problems associated, with applying proof-test-based life prediction to vessels made of high-toughness metals. Two A106 Gr B pipe specimens containing long, through-wall, circumferential flaws were rested. One failed during hydrostatic testing and the other during tension-tension cycling following a hydrostatic test. Quantitative fractography was used to verify experimentally obtained fatigue crack growth rates and a variety of LEFM and EPFM techniques were used to analyze the experimental results. The results show that plastic collapse analysis provides accurate predictions of screened (initial) crack size when the flow stress is determined experimentally; LEFM analysis underestimates the crack size screened by the proof test and overpredicts the subsequent fatigue life of the vessel when retardation effects are small (i.e., low proof levels); and, at a high proof-rest level (2.4 x operating pressure), the large retardation effect on fatigue crack growth due to the overload overwhelmed the deleterious effect on fatigue life from stable rearing during the proof test and alleviated the problem of screening only long cracks due to the high toughness of the metal. C1 STANFORD UNIV,DEPT MECH ENGN,STANFORD,CA 94305. RP Panontin, TL (reprint author), NASA,AMES RES CTR,MECH SYST & MAT ENGN BRANCH,MOFFETT FIELD,CA 94035, USA. RI Hill, Michael/A-2525-2016 OI Hill, Michael/0000-0002-9168-211X NR 14 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD FEB PY 1996 VL 118 IS 1 BP 86 EP 94 DI 10.1115/1.2842168 PG 9 WC Engineering, Mechanical SC Engineering GA TW723 UT WOS:A1996TW72300014 ER PT J AU Hojer, S May, RD Miller, CE AF Hojer, S May, RD Miller, CE TI Intensities of the 1397 cm(-1)(nu(3)) band of HO2NO2 and feasibility of atmospheric detection SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID SPECTRA AB Absorption coefficients of the 1397 cm(-1) (nu(3)), band of peroxynitric acid (HO2NO2) have been measured at 225-230 K in order to calculate the feasibility of detecting this spectral feature in atmospheric spectra. High-resolution (0.0078 cm(-1)) Fourier transform spectra (1370-1430 cm(-1)) of low pressure gas-mixtures containing HO2NO2 were analyzed to determine the absorption coefficient k(nu). The maximum absorption coefficient was found to be 1.0 x 10(-18) cm(2)/molec at the peak of the 1397 cm(-1) Q-branch. An average pressure broadening coefficient of 0.1 (+/- 0.02) cm(-1)/atm was also measured using a tunable diode laser spectrometer (resolution 0.001 cm(-1)) and a convolution technique. The high resolution spectrum and pressure broadening coefficient were used to simulate the atmospheric transmission spectrum at an altitude where HO2NO2 is expected to have its peak in the vertical concentration profile (27 km). RP Hojer, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 5 Z9 5 U1 1 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 FEB PY 1996 VL 55 IS 2 BP 273 EP 278 DI 10.1016/0022-4073(95)00132-8 PG 6 WC Optics; Spectroscopy SC Optics; Spectroscopy GA TV375 UT WOS:A1996TV37500015 ER PT J AU McManus, HL Bowles, DE Tompkins, SS AF McManus, HL Bowles, DE Tompkins, SS TI Prediction of thermal cycling induced matrix cracking SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article ID TRANSVERSE CRACKING; LAMINATE AB Thermal fatigue has been observed to cause matrix cracking in laminated composite materials. A method is presented to predict transverse matrix cracks in a composite laminate subjected to cyclic thermal load. Shear lag stress approximations and a simple energy-based failure criteria are used to predict crack density as a function of temperature. Prediction of crack density as a function of thermal cycling is accomplished by assuming that fatigue degrades the material's inherent resistance to cracking. The method is implemented as a computer program. Simple experiments provide data on progressive cracking of a laminate with decreasing temperature, and on cracking induced by thermal cycling. Correlation of the analytical predictions to the data is very good. A parametric study using the analytical method is presented which provides insight into material behavior under cyclical thermal loads. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP McManus, HL (reprint author), MIT,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. NR 15 TC 19 Z9 19 U1 0 U2 1 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PD FEB PY 1996 VL 15 IS 2 BP 124 EP 140 PG 17 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA UA103 UT WOS:A1996UA10300001 ER PT J AU Seraji, H Lim, D Steele, R AF Seraji, H Lim, D Steele, R TI Experiments in contact control SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article ID CONFIGURATION CONTROL; REDUNDANT MANIPULATORS; MOTION AB This article describes the implementation, experimentation, and application of contact control schemes for a 7-DOF Robotics Research arm. The contact forces and torques are measured in the sensor frame by the 6-axis force/torque sensor mounted at the wrist, are compensated for gravity, and then are transformed to the tool frame in which the contact task is defined and executed. The contact control schemes are implemented on the existing robot Cartesian position control system at 400 Hz, do not require force rate information, and are extremely simple and computationally fast. Three types of contact control schemes are presented: compliance control, force control, and dual-mode control. In the compliance control scheme, the contact force is fed back through a lag-plus-feedforward compliance controller so that the end-effector behaves like a spring with adjustable stiffness; thus the contact force can be controlled by the reference position command. In the force control scheme, a force setpoint is used as the command input and a proportional-plus-integral force controller is employed to ensure that the contact force tracks the force setpoint accurately. In the dual-mode control scheme, the end-effector approaches and impacts the reaction surface in compliance mode, and the control scheme is then switched automatically to force mode after the initial contact has been established. Experimental results are presented to demonstrate contact with hard and soft surfaces under the three proposed control schemes. The article is concluded with the application of the proposed schemes to perform a contact-based eddy-current inspection task. In this task, the robot first approaches the inspection surface in compliance control until it feels that it has touched the surface, and then automatically levels the end-effector on the surface. The robot control system then transitions to force control and applies the desired force on the surface while executing a scanning motion. At the completion of the inspection task, the robot first relaxes the applied force and then retracts from the surface. (C) 1996 John Wiley & Sons, Inc. RP Seraji, H (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 16 Z9 17 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0741-2223 J9 J ROBOTIC SYST JI J. Robot. Syst. PD FEB PY 1996 VL 13 IS 2 BP 53 EP 73 DI 10.1002/(SICI)1097-4563(199602)13:2<53::AID-ROB1>3.0.CO;2-T PG 21 WC Robotics SC Robotics GA TR408 UT WOS:A1996TR40800001 ER PT J AU Townsend, LW Meader, WE AF Townsend, LW Meader, WE TI Vibrational relaxation and sound absorption and dispersion in binary mixtures of gases SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID ATMOSPHERIC ABSORPTION AB Reaction kinetics is used in concert with the usual gas species continuity and momentum equations to derive a pure wave equation for a single parameter (pressure or density). Solutions are obtained for sound absorption and dispersion in a binary mixture of gases which are equivalent to those derived from the phenomenological theory of irreversible thermodynamics. The methods are illustrated by comparison with acoustic measurements of vibrational relaxation in nitrogen-water vapor mixtures near room temperature. RP Townsend, LW (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 168,HAMPTON,VA 23681, USA. NR 17 TC 4 Z9 4 U1 0 U2 1 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 FEB PY 1996 VL 99 IS 2 BP 920 EP 925 DI 10.1121/1.414619 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA TU680 UT WOS:A1996TU68000030 ER PT J AU Bass, HE Sutherland, LC Zuckerwar, AJ Blackstock, DT Hester, DM AF Bass, HE Sutherland, LC Zuckerwar, AJ Blackstock, DT Hester, DM TI Atmospheric absorption of sound: Further developments (vol 97, pg 680, 1995) SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Correction, Addition C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. UNIV TEXAS,APPL RES LABS,AUSTIN,TX 78713. UNIV TEXAS,DEPT MECH ENGN,AUSTIN,TX 78713. RP Bass, HE (reprint author), UNIV MISSISSIPPI,PHYS ACOUST RES GRP,UNIVERSITY,MS 38677, USA. NR 1 TC 27 Z9 27 U1 3 U2 11 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 FEB PY 1996 VL 99 IS 2 BP 1259 EP 1259 DI 10.1121/1.415223 PG 1 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA TU680 UT WOS:A1996TU68000070 ER PT J AU Hollingsworth, JL Barnes, JR AF Hollingsworth, JL Barnes, JR TI Forced stationary planetary waves in Mars's winter atmosphere SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODEL; MARTIAN ATMOSPHERE; INFRARED SPECTROSCOPY; DUST STORMS; MARINER-9; OROGRAPHY; INSTABILITY; SIMULATIONS; PROPAGATION; DYNAMICS AB Mariner 9 and Viking spacecraft observations provided evidence for planetary-scale, wavelike disturbances in the Mars winter atmosphere. Possible sources of the wave activity are dynamical instabilities, for example, barotropic and/or baroclinic instabilities. Other candidate sources are forced, quasi-stationary planetary waves-waves that arise predominantly via zonally asymmetric surface properties. The authors attempt to model aspects of the wave activity, focusing on forced planetary waves in representative wintertime atmospheres for Mars, by applying a spherical linear primitive equations model. Basic states representing relatively ''nondusty'' and ''highly dusty'' conditions near winter solstice allow wavenumber 1 and 2 disturbances to propagate meridionally and vertically about the jet. Higher wavenumbers are strongly vertically trapped. Stationary waves during winter in the northern and southern extratropics differ strongly in amplitude, phase, and dominant horizontal wave pattern. Northern extratropical eddies exhibit a definite wavenumber 2 pattern with comparable amplitudes for wavenumbers 1 and 2. Southern eddies, however, are very strongly dominated by wavenumber 1. Because of enhanced refractive properties of the dusty basic state, dusty responses are an order of magnitude larger than nondusty ones. Horizontal and meridional wave propagation is illuminated by diagnostics for the wave activity flux, for example, Eliassen-Palm and Plumb fluxes. As a result of the separation distance between major orographic features on Mars, together with a planetary waveguide that enhances zonal propagation, Rossby wave interferences between western and eastern hemispheric wave trains occur. This analysis is relevant to future global mapping missions to Mars (e.g., polar-orbiting spacecraft) that will return key atmospheric observations of planetary wave activity. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. OREGON STATE UNIV, COLL OCEAN & ATMOSPHER SCI, CORVALLIS, OR 97331 USA. NR 52 TC 56 Z9 56 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 FEB 1 PY 1996 VL 53 IS 3 BP 428 EP 448 DI 10.1175/1520-0469(1996)053<0428:FSPWIM>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TW815 UT WOS:A1996TW81500006 ER PT J AU Cohn, SE Todling, R AF Cohn, SE Todling, R TI Approximate data assimilation schemes for stable and unstable dynamics SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article AB Two suboptimal data assimilation schemes for stable and unstable dynamics are introduced. The first scheme, the partial singular value decomposition filter, is based on the most dominant singular modes of the tangent linear propagator. The second scheme, the partial eigendecomposition filter, is based on the most dominant eigenmodes of the propagated analysis error covariance matrix. Both schemes rely on iterative procedures like the Lanczos algorithm to compute the relevant modes. The performance of these schemes is evaluated for a shallow-water model linearized about an unstable Bickley jet. The results are contrasted against those of a reduced resolution filter, in which the gains used to update the state vector are calculated from a lower-dimensional dynamics than the dynamics that evolve the state itself. The results are also contrasted against the exact results given by the Kalman filter. These schemes are validated for the case of stable dynamics as well. The two new approximate assimilation schemes are shown to perform well with relatively few modes computed. Adaptive tuning of a modeled trailing error covariance for all three of these low-rank approximate schemes enhances performance and compensates for the approximation employed. RP Cohn, SE (reprint author), NASA, GODDARD SPACE FLIGHT CTR, DATA ASSIMILAT OFF, UNIV SPACE RES ADM, GREENBELT, MD 20771 USA. RI Cohn, Stephen/K-1954-2012 OI Cohn, Stephen/0000-0001-8506-9354 NR 22 TC 75 Z9 76 U1 0 U2 0 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD FEB PY 1996 VL 74 IS 1 BP 63 EP 75 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB760 UT WOS:A1996UB76000005 ER PT J AU Milman, M Fijany, A AF Milman, M Fijany, A TI Wave-front control algorithms and analysis for a dense adaptive optics system with segmented deformable mirror SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID EQUATION AB We present the development and analysis of wave-front control strategies for large-order adaptive optics systems that use a segmented deformable mirror as the correcting optical element. The system analyzed represents a substantial departure from most conventional adaptive optics systems in that the feedback signal includes both the local wave-front tilt and the relative edge mismatch between adjacent segments. One of the major challenges in designing the wave-front control system is the large number of segments that must be commanded. A fast and nearly optimal method based on the local slope and edge measurements is developed for this system. Fast algorithms offering a massive degree of parallelism are also developed to permit realtime implementation of the control strategies on commercially available, low-cost, parallel architectures. (C) 1996 Optical Society of America RP Milman, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 26 TC 1 Z9 1 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD FEB PY 1996 VL 13 IS 2 BP 365 EP 378 DI 10.1364/JOSAA.13.000365 PG 14 WC Optics SC Optics GA TR258 UT WOS:A1996TR25800018 ER PT J AU Kustas, FM Hanson, RR Summers, JL Miyoshi, K AF Kustas, FM Hanson, RR Summers, JL Miyoshi, K TI Tribological performance of a 3-D carbon-carbon composite .2. Vacuum environment SO LUBRICATION ENGINEERING LA English DT Article DE friction; wear; vacuum; composites ID FRICTION AB The tribological performance of a carbon-carbon (C-C) composite tested under ambient-vacuum (6.7 x 10(-7) Pa) and elevated-temperature (1000 degrees C) vacuum (67 x 10(-7) Pa) conditions was determined using a reciprocating flat-on-pin test technique. The coefficient of friction was observed to decrease with increased applied load, conforming to solid lubrication theory. Environment had a pronounced effect on the tribological performance of C-C. Vacuum tests at room temperature resulted in reduced coefficients of friction compared to ambient air tests. This behavior is presumably due to condensation of vacuum system impurities and outgassed intercalants from the graphite (Gr) in the C-C onto the cold wear surface, which acted as solid lubricants at the wear interface. In contrast, 1000 degrees C vacuum tests resulted in dramatic increases in coefficients of friction. This was attributed to outgassing of intercalants within the Gr and condensation onto cold vacuum system components away from the wear surface. The latter test conditions also resulted in much greater wear damage to the stationary pin with removal of carbon matrix material exposing Gr fibers, which were subsequently fractured. Thus, elevated temperature vacuum conditions provide a harsh tribological environment for C-C composites. C1 LOCKHEED MARTIN ASTRONAUT CO,DENVER,CO 80201. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 12 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 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD FEB PY 1996 VL 52 IS 2 BP 149 EP 154 PG 6 WC Engineering, Mechanical SC Engineering GA TV110 UT WOS:A1996TV11000006 ER PT J AU Banks, HT Smith, RC AF Banks, HT Smith, RC TI Parameter estimation in a structural acoustic system with fully nonlinear coupling conditions SO MATHEMATICAL AND COMPUTER MODELLING LA English DT Article DE parameter identification; structural acoustics; nonlinear partial differential equations ID APPROXIMATION AB A methodology for estimating physical parameters in a class of structural acoustic systems is presented. The general model under consideration consists of an interior cavity which is separated from an exterior disturbance by an enclosing elastic structure. Piezoceramic patches are bonded to or embedded in the structure; these can be used both as actuators and sensors in applications ranging from the control of interior noise levels to the determination of structural flaws through nondestructive evaluation techniques. The presence and excitation of the patches, however, changes the geometry and material properties of the structure as well as involves unknown patch parameters, thus necessitating the development of parameter estimation techniques which are applicable in this coupled setting. In developing a framework for approximation, parameter estimation and implementation, strong consideration is given to the fact that the input operator is unbonded due to the discrete nature of the patches. Moreover, the model is weakly nonlinear as a result of the coupling mechanism between the structural vibrations and the interior acoustic dynamics. Within this context, an illustrating model is given, well-posedness and approximation results are discussed and an applicable parameter estimation methodology is presented. The scheme is then illustrated through several numerical examples with simulations modeling a variety of commonly used structural acoustic techniques for system excitation and data collection. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MATH,AMES,IA 50011. NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681. RP Banks, HT (reprint author), N CAROLINA STATE UNIV,CTR RES SCI COMP,RALEIGH,NC 27695, USA. NR 22 TC 8 Z9 8 U1 0 U2 0 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 FEB PY 1996 VL 23 IS 4 BP 17 EP 50 DI 10.1016/0895-7177(96)00002-7 PG 34 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA TX480 UT WOS:A1996TX48000002 ER PT J AU Rao, KBS Schiffers, H Schuster, H Halford, GR AF Rao, KBS Schiffers, H Schuster, H Halford, GR TI Temperature and strain-rate effects on low-cycle fatigue behavior of alloy 800H SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID DEFORMATION; MECHANISMS; FRACTURE; CRACKING; METALS; CREEP; OXIDE AB The effects of strain rate (4 X 10(-6) to 4 X 10(-3) s(-1)) and temperature on the low-cycle fatigue (LCF) behavior of alloy 800H have been evaluated in the range 750 degrees C to 950 degrees C. Total axial strain controlled LCF tests were conducted in air at a strain amplitude of +/-0.30 pet. Low-cycle fatigue life decreased with decreasing strain rate and increasing temperature. The cyclic stress response behavior showed a marked variation with temperature and strain rate. The time- and temperature-dependent processes which influence the cyclic stress response and life have been identified and their relative importance assessed. Dynamic strain aging, time-dependent deformation, precipitation of parallel platelets of M(23)C(6) on grain boundaries and incoherent ledges of twins, and oxidation were found to operate depending on the test conditions. The largest effect on life was shown by oxidation processes. C1 INST MAT ENERGY SYST,MECH TESTING LAB,D-52428 JULICH,GERMANY. RP Rao, KBS (reprint author), NASA,LEWIS RES CTR,DIV STRUCT,CLEVELAND,OH 44135, USA. NR 56 TC 19 Z9 20 U1 1 U2 8 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD FEB PY 1996 VL 27 IS 2 BP 255 EP 267 DI 10.1007/BF02648404 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA TU429 UT WOS:A1996TU42900002 ER PT J AU Keenan, FP Thomas, RJ Neupert, WM Foster, VJ Brown, PJF Tayal, SS AF Keenan, FP Thomas, RJ Neupert, WM Foster, VJ Brown, PJF Tayal, SS TI Fe XII emission lines in spectra obtained with the Solar EUV Rocket Telescope and Spectrograph (SERTS) SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE atomic data; Sun, activity; Sun, flares; ultraviolet, general ID ELECTRON-DENSITY DIAGNOSTICS; OSCILLATOR-STRENGTHS; ENERGY-LEVELS; RATIOS; TRANSITIONS; CORONA; SUN; EXCITATION; FLARES; PLASMA AB Many intensity ratios involving Fe XII 3s(2)3p(3)-3s3p(4) and 3s(2)3p(3)-3s(2)3p(2)3d transitions in the 186-383 Angstrom wavelength range are known to be sensitive to electron density. We compare calculations for these lines with observations of a solar active region and of a subflare obtained during the 1989 flight of the Solar EUV Rocket Telescope and Spectrograph (SERTS). Electron densities derived from the majority of such ratios are consistent with one another for both solar features, and are also in good agreement with the values of N-e estimated from diagnostic lines in other species formed at similar electron temperatures to Fe XII, such as Fe XIII and Fe XIV. These results provide observational support for the general accuracy of the diagnostic calculations, and imply that they may be applied to future observations planned with the Coronal Diagnostic Spectrometer on the SOHO mission. In addition, our analysis indicates that the Line at 283.70 Angstrom in the active region data is the 3s(2)3p(3 2)D(3/2)-3s3p(4 2)P(1/2) transition in Fe XII, the first time (to the best of our knowledge) that this line has been identified in the solar spectrum. Five of the line ratios considered are predicted to be relatively insensitive to the adopted electron temperature and density, and the good agreement found between theory and observation for three of these provides evidence for the reliability of the SERTS instrument calibration. However, for one of the remaining ratios the large discrepancies between theory and observation cannot be attributed to blending, and may be due to errors in the adopted atomic data. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. CLARK ATLANTA UNIV,DEPT PHYS,ATLANTA,GA 30314. CLARK ATLANTA UNIV,CTR THEORET STUDIES PHYS SYST,ATLANTA,GA 30314. RP Keenan, FP (reprint author), QUEENS UNIV BELFAST,DEPT PURE & APPL PHYS,BELFAST BT7 1NN,ANTRIM,NORTH IRELAND. NR 28 TC 18 Z9 18 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 FEB 1 PY 1996 VL 278 IS 3 BP 773 EP 780 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TU105 UT WOS:A1996TU10500011 ER PT J AU Somers, MW Mukai, K Naylor, T AF Somers, MW Mukai, K Naylor, T TI Infrared photometry of WY Sge: Just an ordinary old nova? SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE eclipses; binaries, close; binaries, eclipsing; stars, individual, WY Sge; novae, cataclysmic variables; infrared, stars ID CATACLYSMIC VARIABLES; DWARF; EVOLUTION; BINARIES; LIGHT; STARS AB We present IR photometry of the eclipsing old nova WY Sge (Nova Sagittae 1783), for which we derive a new ephemeris. The ratio of light from the disc and white dwarf to that of the secondary star is typical for an old nova, but at least nine times larger than that of similar period eclipsing dwarf novae. To account for the phase of maximum light it is necessary to invoke some heating of the inner face of the Roche lobe filling star. From this we infer that the heating energy absorbed is 25 +/- 10 per cent of the intrinsic luminosity of the secondary. The colours in and out of the eclipse are used to set limits on the distance and reddening. The dereddened colours are compared with other old novae; there appears to be no significant difference. We conclude that WY Sge is not a dwarf nova and thus has remained at a high mass transfer rate. We suggest that if the mass transfer is driven by irradiation then it is unlikely to decrease in the near future. In any case, models suggest that the irradiation measured is unlikely to be sufficient to drive the observed mass transfer rate. C1 NASA,GODDARD SPACE FLIGHT CTR,OFF GUEST INVESTIGATOR PROGRAMS,GREENBELT,MD 20771. RP Somers, MW (reprint author), UNIV KEELE,DEPT PHYS,KEELE ST5 5BG,STAFFS,ENGLAND. RI Naylor, Tim /A-9465-2015 NR 35 TC 19 Z9 19 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 FEB 1 PY 1996 VL 278 IS 3 BP 845 EP 853 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TU105 UT WOS:A1996TU10500019 ER PT J AU Schubert, S Chang, YH AF Schubert, S Chang, YH TI An objective method for inferring sources of model error SO MONTHLY WEATHER REVIEW LA English DT Article AB A restricted statistical correction (RSC) approach is introduced to assess the sources of error in general circulation models (GCMs). RSC models short-term forecast error by considering linear transformations of the GCM's forcing terms, which produce a ''best'' model in a restricted least squares sense. The results of RSC provide 1) a partitioning of the systematic error among the various GCM's forcing terms, and 2) a consistent partitioning of the nonsystematic error among the GCM forcing terms, which maximize the explained variance. In practice, RSC requires a substantial reduction in the dimensionality of the resulting regression problem: the approach described here projects the fields on the eigenvectors of the error covariance matrix. An example of RSC is presented for the Goddard Earth Observing System (GEOS) GCM's vertically integrated moisture equation over the continental United States during spring. The results are based on the history of analysis increments (''errors'') from a multiyear data assimilation experiment employing the GEOS model. The RSC analysis suggests that during early spring the short-term systematic forecast errors in the vertically integrated moisture are dominated by errors in the evaporation held, while during late spring the errors are large in both the precipitation and evaporation fields. The RSC results further suggest that one-quarter to one-half of the nonsystematic forecast en ors in the vertically integrated moisture may be attributable to GCM deficiencies. Limitations of the method resulting from ambiguities in the nature of the analysis increments are discussed. While the RSC approach was specifically developed to take advantage of data assimilation experiments, it should also be useful for analyzing sequences of somewhat longer GCM forecasts (similar to 1 day) as long as they are short enough to consider the errors approximately local. RP Schubert, S (reprint author), NASA, GODDARD SPACE FLIGHT CTR, MAIL CODE 9103, GREENBELT, MD 20771 USA. NR 18 TC 34 Z9 36 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD FEB PY 1996 VL 124 IS 2 BP 325 EP 340 DI 10.1175/1520-0493(1996)124<0325:AOMFIS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UB902 UT WOS:A1996UB90200008 ER PT J AU Katz, R Cucinotta, FA Zhang, CX AF Katz, R Cucinotta, FA Zhang, CX TI The calculation of radial dose from heavy ions: Predictions of biological action cross sections SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 3rd International Conference on Swift Heavy Ions in Matter (SHIM 95) CY MAY 15-19, 1995 CL CAEN, FRANCE SP CIRIL, GANIL, GSI ID LIQUID WATER; ELECTRONS; INACTIVATION AB The track structure model of heavy ion cross sections was developed by Katz and co-workers in the 1960s. In this model the action cross section is evaluated by mapping the dose-response of a detector to gamma rays (modeled from biological target theory) onto the radial dose distribution from delta rays about the path of the ion. This is taken to yield the radial distribution of probability for a ''hit'' (an interaction leading to an observable end-point). Radial integration of the probability yields the cross section. When different response from ions of different Z having the same stopping power is observed this model may be indicated. Since the 1960s there have been several developments in the computation of the radial dose distribution, in the measurement of these distributions, and in new radiobiological data against which to test the model. The earliest model, by Butts and Katz, made use of simplified delta ray distribution functions, of simplified electron range-energy relations, and neglected angular distributions. Nevertheless it made possible the calculation of cross sections for the inactivation of enzymes and viruses, and allowed extension to tracks in nuclear emulsions and other detectors and to biological cells. It set the pattern for models of observable effects in the matter through which the ion passed. Here we outline subsequent calculations of radial dose which make use of improved knowledge of the electron emission spectrum, the electron range-energy relation, the angular distribution, and some considerations of molecular excitation, of particular interest both close to the path of the ion and the outer limits of electron penetration. These are applied to the modeling of action cross sections for the inactivation of several strains of E-coli and B. subtilis sports where extensive measurements in the ''thin-down'' region have been made with heavy ion beams. Such calculations serve to test the radial dose calculations at the outer limit of electron penetration. We lack data from which to test these calculations in regions close to the path of the ion aside from our earliest work on latent tracks in plastics, though it appears that the criterion then suggested for the threshold of track formation, of a minimal dose at a minimal distance (of about 20 Angstrom, in plastics), remains valid. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. ZHONGSHAN UNIV,DEPT PHYS,GUANGZHOU 510275,PEOPLES R CHINA. RP Katz, R (reprint author), UNIV NEBRASKA,LINCOLN,NE 68588, USA. NR 23 TC 31 Z9 31 U1 0 U2 6 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 FEB PY 1996 VL 107 IS 1-4 BP 287 EP 291 DI 10.1016/0168-583X(95)01011-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UF523 UT WOS:A1996UF52300057 PM 11540424 ER PT J AU Chun, SY Khandelwal, GS Wilson, JW AF Chun, SY Khandelwal, GS Wilson, JW TI A Green's function method for high charge and energy ion transport SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID 670A MEV NE-20; DEPTH; WATER; FRAGMENTATION AB A heavy-ion transport code using Green's function methods is developed. The low-order perturbation terms exhibiting the greatest energy variation are used as dominant energy-dependent terms, and the higher order collision terms are evaluated using nonperturbative methods. The recently revised NUCFRG database is used to evaluate the solution for comparison with experimental data for 625A MeY Ne-20 and 517A MeY Ar-40 ion beams. Improved agreements with the attenuation characteristics for neon ions are found, and reasonable agreement is obtained for the transport of argon ions in wafer. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP Chun, SY (reprint author), OLD DOMINION UNIV,DEPT PHYS,NORFOLK,VA 23529, USA. NR 27 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 1996 VL 122 IS 2 BP 267 EP 275 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA TV080 UT WOS:A1996TV08000010 PM 11543202 ER PT J AU Cai, LZ Jin, YH Zhou, SM Yeh, PC Marzwell, N Liu, HK AF Cai, LZ Jin, YH Zhou, SM Yeh, PC Marzwell, N Liu, HK TI Translation sensitivity adjustable compact optical correlator and its application for fingerprint recognition SO OPTICAL ENGINEERING LA English DT Article DE correlation; correlator; pattern recognition; translation sensitivity; correlation degradation; nonparaxial diffraction; fingerprint identification AB A translation sensitivity adjustable compact optical correlator (TSACOC) utilizing a convergent reference wave has been designed and tested. Its properties and performances, including the location of the correlation peak and the effects of lateral and longitudinal displacements for both filters and input images, are systematically analyzed based on the nonparaxial approximation for the reference beam. The theoretical analyses have been verified in experiments. By discussing the practical problems encountered, we have found that the tolerance of the system to the input lateral displacement can be conveniently increased by changing a geometric factor of the system. This property is very important to a TSACOC with a pinhole aperture attached to an ordinary detector at a fixed place. In addition, the effectiveness of the TSACOC for fingerprint recognition is also presented. (C) 1996 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, JET PROPULS LAB, PASADENA, CA 91109 USA. UNIV SO ALABAMA, DEPT ELECT & COMP ENGN, MOBILE, AL 36688 USA. RP Cai, LZ (reprint author), STAND INT INC, GARDENA, CA 90248 USA. RI Yeh, Pochi/A-2109-2010 NR 12 TC 5 Z9 5 U1 0 U2 1 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD FEB PY 1996 VL 35 IS 2 BP 415 EP 422 DI 10.1117/1.600910 PG 8 WC Optics SC Optics GA TV854 UT WOS:A1996TV85400014 ER PT J AU Giampieri, G Hellings, RW Tinto, M Faller, JE AF Giampieri, G Hellings, RW Tinto, M Faller, JE TI Algorithms for unequal-arm Michelson interferometers SO OPTICS COMMUNICATIONS LA English DT Article AB A method of data acquisition and data analysis is described in which the performance of Michelson-type interferometers with unequal arms can be made nearly the same as interferometers with equal arms. The method requires a separate readout of the relative phase in each arm, made by interfering the returning beam in each arm with a fraction of the outgoing beam. Instead of throwing away the information from a single arm by subtracting it from that from the other arm, the data in one arm is first used to estimate the laser phase noise and then correct for its effect in the normal differenced interferometer data. C1 JOINT INST LAB ASTROPHYS,BOULDER,CO 80302. RP Giampieri, G (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 7 TC 22 Z9 22 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 FEB 1 PY 1996 VL 123 IS 4-6 BP 669 EP 678 DI 10.1016/0030-4018(95)00611-7 PG 10 WC Optics SC Optics GA UB636 UT WOS:A1996UB63600045 ER PT J AU Davis, WL McKay, CP AF Davis, WL McKay, CP TI Origins of life: A comparison of theories and application to Mars SO ORIGINS OF LIFE AND EVOLUTION OF BIOSPHERES LA English DT Review ID EARLY EARTH; TERRESTRIAL PLANETS; ORGANIC-MOLECULES; COMET HALLEY; AMINO-ACIDS; MASS-LOSS; EVOLUTION; MATTER; IMPACT; CARBON AB The field of study that deals with the origins of life does not have a consensus for a theory of life's origin. An analysis of the range of theories offered shows that they share some common features that may be reliable predictors when considering the possible origins of life on another planet. The fundamental datum dealing with the origins of life is that life appeared early in the history of the Earth, probably before 3.5 Ga and possibly before 3.8 Ga. What might be called the standard theory (the Oparin-Haldane theory) posits the production of organic molecules on the early Earth followed by chemical reactions that produced increased organic complexity leading eventually to organic life capable of reproduction, mutation, and selection using organic material as nutrients. A distinct class of other theories (panspermia theories) suggests that life was carried to Earth from elsewhere - these theories receive some support from recent work on planetary impact processes. Other alternatives to the standard model suggest that life arose as an inorganic (clay) form and/or that the initial energy source was not organic material but chemical energy or sunlight. We find that the entire range of current theories suggests that liquid water is the quintessential environmental criterion for both the origin and sustenance of life. It is therefore of interest that during the time that life appeared on Earth we have evidence for liquid water present on the surface of Mars. C1 NASA, AMES RES CTR, DIV SPACE SCI, MOFFETT FIELD, CA 94035 USA. RP NASA, AMES RES CTR, SETI INST, MOFFETT FIELD, CA 94035 USA. NR 115 TC 41 Z9 43 U1 31 U2 194 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 EI 1573-0875 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD FEB PY 1996 VL 26 IS 1 BP 61 EP 73 DI 10.1007/BF01808160 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA UD305 UT WOS:A1996UD30500006 PM 8920171 ER PT J AU Johnson, CF Brown, CS Wheeler, RM Sager, JC Chapman, DK Deitzer, GF AF Johnson, CF Brown, CS Wheeler, RM Sager, JC Chapman, DK Deitzer, GF TI Infrared light-emitting diode radiation causes gravitropic and morphological effects in dark-grown oat seedlings SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID SUNFLOWER HYPOCOTYLS; PHYTOCHROME; CIRCUMNUTATIONS; MESOCOTYL AB Oat (Avena sativa cv Seger) seedlings were irradiated with IR Light-emitting diode (LED) radiation passed through a visible-light-blocking filter. Infrared LED irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature, Thus, the oat seedlings in this study were able to detect IR LED radiation. These findings call into question the use of IR LED as a safe-light for some photosensitive plant response experiments. These findings also expand the defined range of wavelengths involved in radiation-gravity (light-gravity) interactions to include wavelengths in the IR region of the spectrum. C1 NASA,KENNEDY SPACE CTR,FL 32899. UNIV MARYLAND,DEPT HORT & LANDSCAPE ARCHITECTURE,COLLEGE PK,MD 20742. RP Johnson, CF (reprint author), DYNAMAC CORP,MAIL CODE DYN-3,KENNEDY SPACE CTR,FL 32899, USA. NR 20 TC 11 Z9 12 U1 1 U2 5 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD FEB PY 1996 VL 63 IS 2 BP 238 EP 242 DI 10.1111/j.1751-1097.1996.tb03020.x PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA TV096 UT WOS:A1996TV09600015 PM 11536734 ER PT J AU Stallcop, JR Partridge, H Levin, E AF Stallcop, JR Partridge, H Levin, E TI Ab initio potential-energy surfaces and electron-spin-exchange cross sections for H-O-2 interactions SO PHYSICAL REVIEW A LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; LONG-RANGE INTERACTION; THEORETICAL CHARACTERIZATION; COLLISION INTEGRALS; HYDROGEN-ATOMS; INELASTIC-SCATTERING; BASIS-SETS; APPROXIMATION; COEFFICIENTS; MOLECULE AB Accurate quartet- and doublet-state potential-energy surfaces for the interaction of a hydrogen atom and an oxygen molecule in their ground states have been determined from an ab initio calculation using large-basis sets and the internally contracted multireference configuration interaction method. These potential surfaces have been used to calculate the H-O-2 electron-spin-exchange cross section; the square root of the cross section (in no), not taking into account inelastic effects, can be obtained approximately from the expressions 2.390E(-1/6) and 5.266-0.708 log(10)(E) at low and high collision energies E (in E(h)), respectively. These functional forms, as well as the oscillatory structure of the cross section found at high energies, are expected from the nature of the interaction energy. The mean cross section (the cross section averaged over a Maxwellian velocity distribution) agrees reasonably well with the results of measurements. C1 NASA, AMES RES CTR, THERMOSCI INST, MOFFETT FIELD, CA 94035 USA. RP NASA, AMES RES CTR, SPACE TECHNOL DIV, COMPUTAT CHEM BRANCH, MOFFETT FIELD, CA 94035 USA. NR 44 TC 14 Z9 14 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD FEB PY 1996 VL 53 IS 2 BP 766 EP 771 DI 10.1103/PhysRevA.53.766 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TV648 UT WOS:A1996TV64800018 ER PT J AU Artoni, M Bulatov, A Birman, J AF Artoni, M Bulatov, A Birman, J TI Zero-point noise in a nonstationary dielectric cavity SO PHYSICAL REVIEW A LA English DT Article ID MOVING MIRRORS; QUANTUM OPTICS; RADIATION AB The vacuum field in a dielectric cavity where the medium has a rapidly changing time-dependent refractive index exhibits nonclassical features that are directly related to the distortion of the vacuum fluctuations of the field. For appropriate parameters, these nonclassical effects are appreciable enough that a suitable measure of the change in the zero-point noise of the cavity field could provide a way to probe distortions of the vacuum fluctuations. C1 CUNY CITY COLL,DEPT PHYS,NEW YORK,NY 10031. RP Artoni, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,PHOTON DIV 715,GREENBELT,MD 20771, USA. RI Boulatov, Alexei/A-7096-2014 NR 21 TC 14 Z9 14 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 FEB PY 1996 VL 53 IS 2 BP 1031 EP 1035 DI 10.1103/PhysRevA.53.1031 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TV648 UT WOS:A1996TV64800050 ER PT J AU Canuto, VM Dubovikov, MS AF Canuto, VM Dubovikov, MS TI A dynamical model for turbulence .1. General formalism SO PHYSICS OF FLUIDS LA English DT Article ID ISOTROPIC TURBULENCE; ENERGY-TRANSFER; RENORMALIZATION-GROUP; RANGE AB We propose new dynamical equations to describe fully developed turbulence. We begin with the Wyld equations (WE), which are exact solutions of the NSE. The WE, and their Langevin-like representation, show that nonlinearities induce a turbulent force f(t)(k) and a turbulent viscosity nu(t)(k), which are given by an infinite series of Wyld diagrams. The series for t,(k) is renormalizable, and its sum can be found using RNG methods. The result, Eq. (2a), holds for stirring forces f(ext) with an arbitrary correlation function phi and generalizes previous RNG results, which neglected f(t) and were limited to power law phi similar to k(1-2 epsilon). To recover Kolmogorov law, these earlier RNG-based theories were forced to introduce an ad hoc stirring force with a prescribed phi similar to k(-3). By contrast, we show that similar to k(-3) belongs to phi, which is the correlation function of f(t), and that in the inertial range f(t) much greater than f(ext). The series for phi cannot be summed because of a nonrenormalizable infrared divergence (IR) with an infinite; number of divergent irreducible diagrams. To overcome this difficulty, we use the well-accepted notion of local energy transfer and we derive an,expression for the energy flux Pi(k), Eq. (2d), as well as a dynamical equation for the energy spectrum E(k), Eq. (2b). We also construct the dynamical equations for Reynolds stress spectra (solved in papers II and III). An analogous approach is developed for the temperature field. The model contains no free parameters. Some of its predictions are Kolmogorov spectrum E(k) similar to k(5/3) with Ko = 5/3, in agreement with recent data; temperature spectrum in the inertial-convective region E(theta) similar to Ba<(epsilon)over bar>(1/3) epsilon(theta)k(-5/3) , in agreement with the data; Batchelor constant Ba = sigma(t)Ko. In addition, in papers II and III we carry out extensive comparisons with the laboratory, DNS, LES data, and phenomenological models. The model can be used to construct a subgrid model for LES calculations. (C) 1996 American Institute of Physics. RP Canuto, VM (reprint author), NASA, GODDARD INST SPACE STUDIES, 2880 BROADWAY, NEW YORK, NY 10025 USA. NR 38 TC 65 Z9 67 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 1996 VL 8 IS 2 BP 571 EP 586 DI 10.1063/1.868842 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA TR759 UT WOS:A1996TR75900027 ER PT J AU Canuto, VM Dubovikov, MS AF Canuto, VM Dubovikov, MS TI A dynamical model for turbulence .2. Shear-driven flowsq SO PHYSICS OF FLUIDS LA English DT Article ID PRESSURE STRAIN CORRELATION; REYNOLDS; CLOSURE AB Using the formalism developed in paper I, we treat the case of shear-driven flows. First, we derive the dynamic equations for the Reynolds stress. The equations are expressed in both tensorial and scalar forms, that is, as a set of coupled differential equations for the functions that enter the expansion of the Reynolds stress in terms of basic tensors. We specialize the general results to (a) axisymmetric contraction, (b) plane strain, and (c) homogeneous shear, for which there is a wealth of DNS, LES, and laboratory data to test the predictions of our model. Second, for homogeneous shear, in the inertial range, the equations for the Reynolds stress spectral function can be solved analytically, E(12)(k) = - C epsilon(1/3)Sk(-7/3), which is in excellent agreement with recent data. Since the model has no free parameters, we stress that the model yields a numerical coefficient C, which is also in agreement with the data, Third, we derive the general expressions for the rapid and slow parts of the pressure-strain correlation tensors Pi(ij)(r) and Pi(ij)(s). Within the second-order closure models, the closure of Pi(ij)(s) (third-order moment) in terms of second-order moments continues to be particularly difficult. The general expression for Pi(ij) are then specialized to the three flows discussed above. Pi(ij)(s) is written in the form first suggested by Rotta, we show that the Rotta constant is a When IT nonconstant tenser. Fourth, we discuss the dissipation tensor epsilon(ij). In standard turbulence models, one not only assumes that epsilon(ij) = 2/3 epsilon delta(ij) + f(<(u(i)u(j))over bar>), where f(x) is a empirical function of the one-point Reynolds stress <(u(i)u(j))over bar>, but, in addition, one employs a highly parametrized equation for epsilon. In the present model, neither of the two assumptions is required nor adjustable parameters are needed since epsilon(ij) is computed directly. The model provides the k-dependent R(ij)(k) as one of the primary quantities. (C) 1996 American Institute of Physics. RP Canuto, VM (reprint author), NASA, GODDARD INST SPACE STUDIES, 2880 BROADWAY, NEW YORK, NY 10025 USA. NR 20 TC 29 Z9 29 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 1996 VL 8 IS 2 BP 587 EP 598 DI 10.1063/1.868843 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA TR759 UT WOS:A1996TR75900028 ER PT J AU Canuto, VM Dubovikov, MS Cheng, Y Dienstfrey, A AF Canuto, VM Dubovikov, MS Cheng, Y Dienstfrey, A TI Dynamical model for turbulence .3. Numerical results SO PHYSICS OF FLUIDS LA English DT Article ID TEMPERATURE-FIELD; DISSIPATION-RANGE; SPECTRUM AB We present the numerical solutions of the equations for turbulence developed in papers I and II. The model predicts the Kolmogorov law and Ko=5/3, in accord with recent data; (2)in the inertial-conductive regime, the model predicts the Corrsin spectrum for the temperature variance and the Batchelor constant Ba=sigma(t) Ko, where sigma(t)=0.72 is the turbulent Prandtl number; (3) the predicted energy spectrum in the dissipation region is in agreement with recent laboratory measurements; (4) in the inertial-convective region, the temperature variance spectrum is closer to the spectrum (-11/3) obtained by LES when the velocity field is rapidly stirred at all scales than (-17/3), which holds when the velocity field is frozen in time and has a Gaussian statistics; (5) for freely decaying turbulence, the power law spectra for energy and temperature variance, as well as the velocity and temperature integral scales, agree with the most recent LES data; (6) after a few evolutionary times, the skewness S reaches S=0.5, in accord with a variety of data; (7) for shear-driven flows, the Reynolds stress spectrum E(12)(k) has an inertial regime with a power -7/3, in accord with recent data; (8) for two shear-driven flows, plane strain and axisymmetric contraction, turbulent kinetic energy, Reynolds stress tensor, and dissipation rate epsilon(ij) versus time compare very well with DNS data; (9) the slow and rapid parts of the pressure-strain correlation tensor compare with DNS data better than with the three most widely used phenomenological models. The rapid parts are also in excellent agreement with the DNS data; (10) for homogeneous shear, turbulent kinetic energy and Reynolds stress tensor versus time match quite closely LES data. We recall that the model does not contain any free parameters. (C) 1996 American Institute of Physics. RP Canuto, VM (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 34 TC 26 Z9 26 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 1996 VL 8 IS 2 BP 599 EP 613 DI 10.1063/1.868844 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA TR759 UT WOS:A1996TR75900029 ER PT J AU Winker, DM Couch, RH McCormick, MP AF Winker, DM Couch, RH McCormick, MP TI An overview of LITE: NASA's lidar in-space technology experiment SO PROCEEDINGS OF THE IEEE LA English DT Article ID RETURNS; CLOUDS; STRATOSPHERE; AEROSOLS; SURFACE AB The Lidar In-space Technology Experiment (LITE) is a three-wavelength backscatter lidar developed by NASA Langley Reearch Center to fly on the Space Shuttle. LITE flew on Discovery in September 1994 as part of the STS-64 mission. The goals of the LITE mission were to validate key lidar technologies for spaceborne applications, to explore the applications of space lidar, and to gain operational experience which will benefit the development of future systems on free-flying satellite platforms. The performance of the LITE instrument was excellent, resulting in the collection of over 40 GBytes of data. These data present la with our first highly detailed global view of the vertical structure of cloud and aerosol from the Earth's surface through the middle stratosphere. This paper will discuss the LITE instrument, the LITE mission and briefly present some results from the experiment. These preliminary results highlight the benefits to be obtained from long duration satellite lidars. RP Winker, DM (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 29 TC 175 Z9 181 U1 5 U2 16 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9219 J9 P IEEE JI Proc. IEEE PD FEB PY 1996 VL 84 IS 2 BP 164 EP 180 DI 10.1109/5.482227 PG 17 WC Engineering, Electrical & Electronic SC Engineering GA TU736 UT WOS:A1996TU73600004 ER PT J AU Dhadwal, HS Mehmud, A Khan, R Kurkov, A AF Dhadwal, HS Mehmud, A Khan, R Kurkov, A TI Integrated fiber optic light probe: Measurement of static deflections in rotating turbomachinery SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB This paper describes the design, fabrication, and testing of an integrated fiber optic light probe system for monitoring blade tip deflections, vibrational modes, and changes in blade tip clearances in the compressor stage of rotating turbomachinery. The system comprises a set of integrated fiber optic light probes which are positioned to detect the passing blade tip at the lending and the trailing edges. In this configuration measurements of both blade vibrations and steady-state blade deflection can be obtained from the timing information provided by each light probe, which comprises an integrated fiber optic transmitting channel and a number of high numerical aperture receiving fibers, all mounted in the same cylindrical housing. A spatial resolution of 50 mu m is possible with the integrated fiber optic technology, while keeping the outer diameter below 2.5 mm. Additionally, one fiber sensor provides a capability of monitoring changes in the blade tip clearance of the order of 10 mu m. Measurements from a single stage compressor facility and an engine-fan rig in a 9 ftx15 ft subsonic wind tunnel are presented. (C) 1996 American Institute of Physics. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Dhadwal, HS (reprint author), SUNY STONY BROOK,DEPT ELECT ENGN,STONY BROOK,NY 11794, USA. NR 7 TC 13 Z9 13 U1 0 U2 1 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 FEB PY 1996 VL 67 IS 2 BP 546 EP 552 DI 10.1063/1.1146634 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA TX389 UT WOS:A1996TX38900038 ER PT J AU Stern, DP AF Stern, DP TI A brief history of magnetospheric physics during the space age SO REVIEWS OF GEOPHYSICS LA English DT Review ID FIELD-ALIGNED CURRENTS; INTERPLANETARY MAGNETIC-FIELD; IONOSPHERIC ACCELERATION MECHANISM; CONVECTION ELECTRIC-FIELDS; SUBSTORM GROWTH-PHASE; WIND DYNAMIC PRESSURE; CENTRAL PLASMA SHEET; HOT TENUOUS PLASMAS; EARTHS MAGNETOTAIL; BIRKELAND CURRENTS AB After 1958, when scientific satellites began exploring the Earth magnetic environment, many puzzling phenomena could be directly examined, especially the polar aurora and disturbances of the Earth's magnetic field [see Stem, 1989a]. The notion of the solar wind, also introduced in 1958, helped clarify the role of the Sun in driving such phenomena. The large-scale structure of the magnetosphere, the space region dominated by the Earth's magnetic field, was gradually revealed within the next decade: its trapped particles, its boundary, and its long magnetic tail on the nightside. Inevitably, however, at a more fundamental level, the new discoveries led to new questions about the transfer of energy, the flow patterns of plasmas and electric currents, the acceleration of the aurora, and transient events such as magnetic substorms and storms, which energized ions and electrons. Though significant progress has occurred in some of these areas, many unresolved issues still remain. This review outlines the history of magnetospheric research, draws some general conclusions, and provides an extensive bibliography. RP Stern, DP (reprint author), NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, CODE 695, GREENBELT, MD 20771 USA. NR 389 TC 17 Z9 17 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD FEB PY 1996 VL 34 IS 1 BP 1 EP 31 DI 10.1029/95RG03508 PG 31 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV972 UT WOS:A1996TV97200001 ER PT J AU Miles, RF AF Miles, RF TI Cost-effective risk assessment for process design - Deshotels,R, Zimmerman,RD SO RISK ANALYSIS LA English DT Book Review C1 CALTECH,JET PROP LAB,TECH STAFF,RELIABIL ENGN SECT,PASADENA,CA 91109. RP Miles, RF (reprint author), UNIV SO CALIF,INST SAFETY & SYST MANAGEMENT,LOS ANGELES,CA 90089, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD FEB PY 1996 VL 16 IS 1 BP 127 EP 128 PG 2 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA TZ844 UT WOS:A1996TZ84400013 ER PT J AU Yungster, S Radhakrishnan, K AF Yungster, S Radhakrishnan, K TI A fully implicit time accurate method for hypersonic combustion: Application to shock-induced combustion instability SO SHOCK WAVES LA English DT Article DE reacting flows; unsteady combustion; BDF method; TVD schemes; LU-SGS method ID GASES AB A new fully implicit, time accurate algorithm suitable for chemically reacting, viscous flows in the transonic-to-hypersonic regime is described, The method is based on a class of Total Variation Diminishing (TVD) schemes and uses successive Gauss-Seidel relaxation sweeps. The inversion of large matrices is avoided by partitioning the system into reacting and nonreacting parts, but a fully coupled interaction is still maintained. As a result, the matrices that have to be inverted are of the same size as those obtained with the commonly used point implicit methods. In this paper we illustrate applicability of the new algorithm to hypervelocity unsteady combustion applications. We present a series of numerical simulations of the periodic combustion instabilities observed in ballistic-range experiments of blunt projectiles flying at subdetonative speeds through hydrogen-air mixtures. The computed frequencies of oscillation are in excellent agreement with experimental data. C1 NASA,LEWIS RES CTR,NYMA INC,CLEVELAND,OH 44135. RP Yungster, S (reprint author), NASA,LEWIS RES CTR,INST COMPUTAT MECH PROP,CLEVELAND,OH 44135, USA. NR 24 TC 9 Z9 9 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0938-1287 J9 SHOCK WAVES JI Shock Waves PD FEB PY 1996 VL 5 IS 5 BP 293 EP 303 DI 10.1007/PL00003872 PG 11 WC Mechanics SC Mechanics GA TW801 UT WOS:A1996TW80100004 ER PT J AU Wu, ST Xiao, YC Musielak, ZE Suess, ST AF Wu, ST Xiao, YC Musielak, ZE Suess, ST TI Propagation of MHD body and surface waves in magnetically structured regions of the solar atmosphere SO SOLAR PHYSICS LA English DT Article ID ALFVEN WAVES; VERTICAL MOTIONS; FLUX TUBE; FIELDS; MEDIA AB The fact that magnetically structured regions exist in the solar atmosphere has been known for a number of years. It has been suggested that different kinds of magnetohydrodynamic (MHD) waves can be efficiently damped in these regions and that the dissipated wave energy may be responsible for the observed enhancement in radiative losses. From a theoretical point of view, an important task would be to investigate the propagation and dissipation of MHD waves in these highly structured regions of the solar atmosphere. In this paper, we study the behavior of MHD body and surface waves in a medium with either a single or double (slab) magnetic interface by use of a nonlinear, two-dimensional, time-dependent, ideal MHD numerical model constructed on the basis of a Lagrangean grid and semi-implicit scheme. The processes of wave confinement and wave energy leakage are discussed in detail. It is shown that the obtained results depend strongly on the type of perturbations imposed on the interface or slab and on the plasma parameter, beta. The relevance of the obtained results to the heating problem of the upper parts of the solar atmosphere is also discussed. C1 UNIV ALABAMA,DEPT MECH & AEROSP ENGN,HUNTSVILLE,AL 35899. UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB ES82,HUNTSVILLE,AL 35812. NR 29 TC 7 Z9 7 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 FEB PY 1996 VL 163 IS 2 BP 291 EP 307 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TU847 UT WOS:A1996TU84700008 ER PT J AU Lassiter, JO AF Lassiter, JO TI Microgravity acceleration measurements SO SOUND AND VIBRATION LA English DT Article AB Many payloads flown on the space shuttle or to be flown on the International Space Station Alpha (ISSA) are designed to utilize the microgravity acceleration environment available in Low-Earth Orbit (LEG). However, this environment is sometimes far from being in the microgravity regime because of various disturbances ranging from engine firings to astronaut sneezes. NASA has recognized the need to provide the microgravity environment to these payloads by integration of vibration isolation systems. This article will describe some typical microgravity payloads, excitation sources that cause higher than desired accelerations, microgravity measurement procedures and a type of transducer suitable for microgravity measurements developed during the process of designing an isolation system. RP Lassiter, JO (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ACOUSTICAL PUBL INC PI BAY VILLAGE PA 27101 E OVIATT RD PO BOX 40416, BAY VILLAGE, OH 44140 SN 0038-1810 J9 SOUND VIB JI Sound Vib. PD FEB PY 1996 VL 30 IS 2 BP 16 EP 19 PG 4 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA TZ970 UT WOS:A1996TZ97000004 ER PT J AU Miura, H Chargin, M AF Miura, H Chargin, M TI A modification to the sensitivity analysis algorithm for known target displacements SO STRUCTURAL OPTIMIZATION LA English DT Article AB The purpose of this note is to show that a secant approximation of the displacement state can be obtained by a simple modification of the sensitivity analysis algorithm for static displacements and frequency responses, if the displacement state of the target design is known. When applied to the discretized equilibrium equations obtained by the finite element method, this new approximation contains the target design exactly, if the system matrices are linear functions of the design variables and all components of the displacement vector are known at the target design. Therefore, a single application of a numerical search process to this approximation will reach the target design. The displacement state at the optimal design is not known in advance in design optimization. However, for special applications, such as model updates or the creation of simplified models from very large models, this new approximation could be useful in augmenting the straightforward application of the conventional structural optimization techniques. RP Miura, H (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0934-4373 J9 STRUCT OPTIMIZATION JI Struct. Optim. PD FEB PY 1996 VL 11 IS 1 BP 64 EP 66 DI 10.1007/BF01279657 PG 3 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Mechanics SC Computer Science; Engineering; Mechanics GA TX874 UT WOS:A1996TX87400008 ER PT J AU Finley, CW Ferrante, J AF Finley, CW Ferrante, J TI Spectroscopic parameters of the heteronuclear diatomic molecules of Ni, Pd, Pt, Cu, Ag and Au SO SURFACE AND INTERFACE ANALYSIS LA English DT Article; Proceedings Paper CT Surface Analysis 95 Symposium CY JUN 07-09, 1995 CL STATE COLL, PA SP Amer Vacuum Soc, Appl Surface Sci Div, Penn State Univ, Coll Earth & Mineral Sci ID EMBEDDED-ATOM-METHOD; METALS AB The Embedded Atom Method (EAM) is used to calculate the binding energy curves for heteronuclear diatomic molecules of Ni, Pd, Pt, Cu, Ag and Au. The EAM potentials for the homonuclear metals are modified using two-body potentials for the AB alloys developed by R. A. Johnson. The binding energy curves are fit to the Morse potential and the spectroscopic parameters are determined. For the diatomic alloys for which there are experimental data, EAM gives good agreement in binding energy and the equilibrium harmonic frequency nod good agreement for the anharmonicity constant. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Finley, CW (reprint author), PENN STATE UNIV,NEW KENSINGTON CAMPUS,NEW KENSINGTON,PA 15068, USA. NR 9 TC 2 Z9 3 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD FEB PY 1996 VL 24 IS 2 BP 133 EP 136 DI 10.1002/(SICI)1096-9918(199602)24:2<133::AID-SIA93>3.0.CO;2-0 PG 4 WC Chemistry, Physical SC Chemistry GA TX926 UT WOS:A1996TX92600010 ER PT J AU Singh, J Bhat, BN Poorman, R Kar, A Mazumder, J AF Singh, J Bhat, BN Poorman, R Kar, A Mazumder, J TI Laser glazing of vacuum plasma spray coated NARloy-Z SO SURFACE & COATINGS TECHNOLOGY LA English DT Article DE laser glazing; vacuum plasma spray forming AB A CO2 laser was used to modify the surface layer of vacuum plasma sprayed NARloy-Z (Cu-3 wt.%Ag-0.5 wt.%Zr). The laser glazing dramatically reduced voids and cavities originally present in the alloy matrix. In addition, grain boundary precipitates were eliminated. A highly refined microstructure was obtained with extended solid solubility of solute atoms (Ag and Zr) into the matrix. A theoretical model was developed to predict the melt pool depth that occurred during laser glazing. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. UNIV CENT FLORIDA,DEPT MECH & AEROSP ENGN,CREOL,ORLANDO,FL 32826. UNIV ILLINOIS,DEPT MECH & IND ENGN,CTR LASER AIDED MAT PROC,URBANA,IL 61801. RP Singh, J (reprint author), PENN STATE UNIV,APPL RES LAB,UNIVERSITY PK,PA 16804, USA. NR 7 TC 13 Z9 15 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD FEB PY 1996 VL 79 IS 1-3 BP 35 EP 49 DI 10.1016/0257-8972(95)02441-7 PG 15 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA UB580 UT WOS:A1996UB58000005 ER PT J AU Campbell, MR Billica, RD Jennings, R Johnston, S AF Campbell, MR Billica, RD Jennings, R Johnston, S TI Laparoscopic surgery in weightlessness SO SURGICAL ENDOSCOPY-ULTRASOUND AND INTERVENTIONAL TECHNIQUES LA English DT Article DE laparoscopy; spaceflight; weightlessness; space medicine ID MINIMALLY INVASIVE SURGERY; CHOLECYSTECTOMY; MICROGRAVITY; TRAUMA; PNEUMOPERITONEUM; SPACE; PHASE AB Background: Performing a surgical procedure in weightlessness has been shown not to be any more difficult than in a 1g environment if the requirements for the restraint of the patient, operator, and surgical hardware are observed. The feasibility of performing a laparoscopic surgical procedure in weightlessness, however, has been questionable. Concerns have included the impaired visualization from the lack of gravitational retraction of the bowel and from floating debris such as blood. Methods: In this project, laparoscopic surgery was performed on a porcine animal model in the weightlessness of parabolic flight. Results: Visualization was unaffected due to the tethering of the bowel by the elastic mesentery and the strong tendency for debris and blood to adhere to the abdominal wall due to surface tension forces. Conclusions: There are advantages to performing a laparoscopic instead of an open surgical procedure in a weightless environment. These will become important as the laparoscopic support hardware is miniaturized from its present form, as laparoscopic technology becomes more advanced, and as more surgically capable crew medical officers are present in future long-duration space-exploration missions. RP Campbell, MR (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DEPT MED OPERAT,HOUSTON,TX 77058, USA. NR 29 TC 24 Z9 25 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0930-2794 J9 SURG ENDOSC-ULTRAS JI Surg. Endosc.-Ultrason. Interv. Tech. PD FEB PY 1996 VL 10 IS 2 BP 111 EP 117 PG 7 WC Surgery SC Surgery GA TV341 UT WOS:A1996TV34100003 PM 8932610 ER PT J AU Dzodzo, M Braun, MJ Hendricks, RC AF Dzodzo, M Braun, MJ Hendricks, RC TI Pressure and flow characteristics in a shallow hydrostatic pocket with rounded pocket/land joints SO TRIBOLOGY INTERNATIONAL LA English DT Article; Proceedings Paper CT International Tribology Conference (AUSTRIB 94) CY DEC, 1994 CL PERTH, AUSTRALIA ID JOURNAL BEARING; HEAT AB The paper studies the development of the flow and pressure maps in a shallow hydrostatic bearing pocket and, on a comparative basis, discusses the effects of the pocket-to-land exit geometry when it takes different shapes (sharp 90 degrees angle, and rounded with different radii of curvature). The numerical simulation uses a dimensionless formulation of the Navier-Stokes equations written in primitive variables for a body fitted coordinate system, and applied through a collocated grid. The model includes on one hand the coupling between the pocket flow and a finite length feedline flow, and the pocket and the adjacent lands on the other hand. Geometrically, all pockets have the same footprint, same land length, and same capillary feedline. The numerical simulation uses the Reynolds number (Re) based on the runner velocity, and the inlet jet strength (F) as dynamic similarity parameters, while the radius of curvature of the pocket/land joint is used as a geometric parameter. The study treats the laminar ranges of the Re number. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Dzodzo, M (reprint author), UNIV AKRON,DEPT MECH ENGN,AKRON,OH 44325, USA. RI Dzodzo, Milorad/J-6563-2014 OI Dzodzo, Milorad/0000-0003-4372-0529 NR 43 TC 4 Z9 7 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-679X J9 TRIBOL INT JI Tribol. Int. PD FEB PY 1996 VL 29 IS 1 BP 69 EP 76 DI 10.1016/0301-679X(95)00036-4 PG 8 WC Engineering, Mechanical SC Engineering GA TZ961 UT WOS:A1996TZ96100010 ER PT J AU Choy, FK Polyshchuk, V Zakrajsek, JJ Handschuh, RF Townsend, DP AF Choy, FK Polyshchuk, V Zakrajsek, JJ Handschuh, RF Townsend, DP TI Analysis of the effects of surface pitting and wear on the vibration of a gear transmission system SO TRIBOLOGY INTERNATIONAL LA English DT Article; Proceedings Paper CT International Tribology Conference (AUSTRIB 94) CY DEC, 1994 CL PERTH, AUSTRALIA AB A comprehensive procedure to simulate and analyse the vibrations in a gear transmission system with surface pitting, wear, and partial tooth fracture of the gear teeth is presented. An analytical model was developed where the effects of surface pitting and wear of the gear tooth were simulated by phase and magnitude changes in the gear mesh stiffness. Changes in the gear mesh stiffness were incorporated into each gear-shaft model during the global dynamic simulation of the system. The overall dynamics of the system were evaluated by solving for the transient dynamics of each shaft system simultaneously with the vibration of the gearbox structure. In order to reduce the number of degrees-of-freedom in the system, a modal synthesis procedure was used in the global transient dynamic analysis of the overall transmission system. An FFT procedure was used to transform the averaged time signal into the frequency domain for signature analysis. In addition, the Wigner-Ville distribution was also introduced to examine the gear vibration in the joint time-frequency domain for vibration pattern recognition. Experimental results obtained from a gear fatigue test rig at NASA Lewis Research Center were used to evaluate the analytical model. C1 NASA,WASHINGTON,DC. USA,RES LAB,LEWIS RES CTR,VEHICLE PROPULS DIRECTORATE,WASHINGTON,DC. RP Choy, FK (reprint author), UNIV AKRON,AKRON,OH 44325, USA. NR 13 TC 53 Z9 57 U1 0 U2 21 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-679X J9 TRIBOL INT JI Tribol. Int. PD FEB PY 1996 VL 29 IS 1 BP 77 EP 83 DI 10.1016/0301-679X(95)00037-5 PG 7 WC Engineering, Mechanical SC Engineering GA TZ961 UT WOS:A1996TZ96100011 ER PT J AU Strawn, RC Biswas, R AF Strawn, RC Biswas, R TI Numerical simulations of helicopter aerodynamics and acoustics SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article; Proceedings Paper CT 6th International Congress on Computational and Applied Mathematics CY JUL 26-30, 1994 CL LOUVAIN, BELGIUM SP Belgian Natl Sci Fdn, IBM, Belgium, BBL Antwerpen, SAS Inst, Avia Belgomazout, United Airlines DE helicopter aerodynamics and acoustics; computational fluid dynamics; Kirchhoff integration; dynamic mesh adaption; structured and unstructured grids; rotor in hover and forward flight AB This paper demonstrates several new methods for computing acoustic signals from helicopter rotors in hover and forward flight. Aerodynamic and acoustic solutions in the near field are computed with two different finite-volume flow solvers for the Euler equations. A solution-adaptive unstructured-grid Euler solver models a rotor in hover while a more conventional structured-grid solver is used for forward flight calculations. A nonrotating cylindrical surface is then placed around the entire rotor system. This surface moves subsonically with the rotor hub in forward flight. The finite-volume solution is interpolated onto this cylindrical surface at every time step and a Kirchhoff integration propagates the acoustic signal to the far field. Computed values for high-speed impulsive noise in hover and forward flight show excellent agreement with experimental data. Results from the combined finite-volume/Kirchhoff method offer high accuracy with reasonable computer resource requirements. C1 NASA,AMES RES CTR,US ARMY AFDD,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,RIACS,MOFFETT FIELD,CA 94035. NR 13 TC 4 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD JAN 31 PY 1996 VL 66 IS 1-2 BP 471 EP 483 DI 10.1016/0377-0427(95)00171-9 PG 13 WC Mathematics, Applied SC Mathematics GA UL887 UT WOS:A1996UL88700038 ER PT J AU Lundgren, TS Mansour, NN AF Lundgren, TS Mansour, NN TI Transition to turbulence in an elliptic vortex SO JOURNAL OF FLUID MECHANICS LA English DT Article ID PLANE MIXING LAYER; 3-DIMENSIONAL INSTABILITY; STRAINED VORTICES; FLOW; EVOLUTION; DYNAMICS; FLUID; FIELD AB Stability and transition to turbulence are studied in a simple incompressible two-dimensional bounded swirling flow with a rectangular planform - a vortex in a box. This how is unstable to three-dimensional disturbances. The instability takes the form of counter-rotating swirls perpendicular to the axis which bend the vortex into a periodic wave. As these swirls grow in amplitude the primary vorticity is compressed into thin vortex layers. These develop secondary instabilities which roll up into vortex tubes. In this way the flow attains a turbulent state which is populated by intense elongated vortex tubes and weaker vortex layers which spiral around them. The flow was computed at two Reynolds numbers by spectral methods with up to 256(3) resolution. At the higher Reynolds number broad three-dimensional shell-averaged energy spectra are found with nearly a decade of Kolmogorov k(-5/3) law and small-scale isotropy. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Lundgren, TS (reprint author), UNIV MINNESOTA,DEPT AEROSP ENGN & MECH,MINNEAPOLIS,MN 55455, USA. NR 30 TC 39 Z9 39 U1 1 U2 5 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 JAN 25 PY 1996 VL 307 BP 43 EP 62 DI 10.1017/S0022112096000031 PG 20 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA TV263 UT WOS:A1996TV26300003 ER PT J AU Yelle, RV Young, LA Vervack, RJ Young, R Pfister, L Sandel, BR AF Yelle, RV Young, LA Vervack, RJ Young, R Pfister, L Sandel, BR TI Structure of Jupiter's upper atmosphere: Predictions for Galileo SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID JOVIAN UPPER-ATMOSPHERE; THERMAL PROFILES; RADIO SCIENCE; IONOSPHERE; EMISSIONS; VOYAGER; MESOSPHERE; PRECIPITATION; THERMOSPHERE; ELECTROGLOW AB The Voyager mission to the outer solar system discovered that the thermospheres of all the giant planets are remarkably hot. To date, no convincing explanation for this phenomenon has been offered; however, there are a number of recent observational results which provide new information on the thermal structure of Jupiter's upper atmosphere that bear on this outstanding problem. We present an analysis of Jupiter's thermal structure using constraints from H-3(+) emissions, Voyager UVS occultation data, ground-based stellar occultation data, and the properties of the Jovian UV dayglow. Although the initial, separate analysis of these data sets produced contradictory results, our reanalysis shows that the observations are consistent and that the temperature profile in Jupiter's upper atmosphere is well constrained. We find that the data demand the presence of a large temperature gradient, of order 3-10 K/km, near a pressure of 0.3 mu bar. Analysis of the temperature profile implies that an energy source of roughly 1 erg cm(-2) s(-1) is required to produce the high thermospheric temperature and that this energy must be deposited in the 0.1-1.0 mu bar region. It is also necessary that this energy be deposited above the region where diffusive separation of CH4 occurs, so that the energy is not radiated away by CH4. We show that dissipation of gravity waves can supply the energy required and that this energy will be deposited in the proper region. Moreover, because the turbulent mixing caused by gravity waves determines the level at which diffusive separation of CH4 occurs, the location of the energy source (dissipation of waves) and the energy sink (radiation by CH4) are coupled. We show that the gravity waves will deposit their energy several scale heights above the CH4 layer; energy is carried downward by ther mal conduction in the intervening region, causing the large temperature gradient. Thus dissipation of gravity waves appears to be a likely explanation for the high thermospheric temperature. Our arguments are general and should apply to Saturn, Uranus, and Neptune, as well as Jupiter. The model temperature profiles presented here and the relationship between the gravity wave flux and thermospheric temperature are directly testable by the Atmospheric Structure Instrument carried by the Galileo probe. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RI Vervack, Ronald/C-2702-2016 OI Vervack, Ronald/0000-0002-8227-9564 NR 56 TC 53 Z9 53 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 JAN 25 PY 1996 VL 101 IS E1 BP 2149 EP 2161 DI 10.1029/95JE03384 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TR941 UT WOS:A1996TR94100001 ER PT J AU Roush, TL AF Roush, TL TI Midinfrared (5.0-25 mu m, 2000-400 cm(-1)) optical constants of hydrous carbonate, sulfate, and nitrate SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID THERMAL EMISSION; MARTIAN DUST; SPECTROSCOPY; GYPSUM; MARS; MOON AB Fresnel reflectance and dispersion analysis are used to derive the real and imaginary indices of refraction of hydrous carbonate (dypingite) and hydrous sulfate (fibroferrite), in the 5.0 - 25 mu m wavelength region, and hydrous nitrate/sulfate (darap-skite) in the 5 - 17 mu m wavelength region. These indices are useful for theoretical modeling of the radiative transfer that occurs within atmospheres of planets and particulate surfaces of solid bodies in the solar system. C1 SAN FRANCISCO STATE UNIV,DEPT GEOSCI,SAN FRANCISCO,CA 94132. RP Roush, TL (reprint author), NASA,AMES RES CTR,MS 245-3,MOFFETT FIELD,CA 94035, USA. NR 38 TC 5 Z9 5 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 JAN 25 PY 1996 VL 101 IS E1 BP 2215 EP 2224 DI 10.1029/95JE03364 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TR941 UT WOS:A1996TR94100006 ER PT J AU Woo, R AF Woo, R TI Kilometre-scale structures in the Sun's corona SO NATURE LA English DT Article ID INNER SOLAR-WIND; DENSITY-FLUCTUATIONS; TRANSITION REGION; TURBULENCE; HOLES; FIELD; SPEED; WAVES AB KNOWLEDGE of the structure of the Sun's corona is important for our understanding of how this high-temperature plasma is heated, and of the processes involved in the acceleration of the solar wind(1,2). The structure can be investigated directly by imaging at optical and shorter wavelengths, or indirectly through the effects of changing electron density on the propagation of radio waves (scattering and scintillation). Radio measurements have established many of the characteristics of the density fluctuations in the corona and solar wind, but the fundamental nature of these structures is not yet fully understood(3,4). Two specific features that have proved difficult to explain are an abrupt increase in anisotropy of the irregularities close to the Sun(5-7), and a break in the power-law spectrum describing the density fluctuations(8,9). Here I argue that these features are the manifestation of a transition from small ray-like or filamentary structures in the corona that rotate with the Sun to turbulent density irregularities convecting with the solar sind. I estimate the size of the smallest filamentary structure within coronal holes to be about 1 km at the Sun, approximately three orders of magnitude smaller than the smallest filamentary structures observed in images of different wavelengths(2,10-12). RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 36 TC 47 Z9 47 U1 0 U2 1 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD JAN 25 PY 1996 VL 379 IS 6563 BP 321 EP 322 DI 10.1038/379321a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TR323 UT WOS:A1996TR32300050 ER PT J AU Wang, PH Kent, GS McCormick, MP Thomason, LW Yue, GK AF Wang, PH Kent, GS McCormick, MP Thomason, LW Yue, GK TI Retrieval analysis of aerosol-size distribution with simulated extinction measurements at SAGE III wavelengths SO APPLIED OPTICS LA English DT Article DE remote sensing; aerosol-extinction coefficient; aerosol-size distribution retrieval ID STRATOSPHERIC AEROSOL; OPTICAL-MODEL; SATELLITE; PROFILES; DEPLETION; OZONE AB The retrieval of aerosol-size distribution from simulated aerosol-extinction-coefficient measurements of the new satellite instrument, the Stratospheric Aerosol and Gas Experiment (SAGE) III, is investigated. A detailed discussion on the aerosol-size-distribution information content of the SAGE III aerosol-extinction-coefficient measurement is provided. Results of the investigation indicate that unimodal as well as bimodal log-normal size distributions can be inferred. In addition, it is shown that a shape-constraint-free size distribution can be derived from SAGE III aerosol measurements by use of the randomized minimization search technique and the optimal estimation theory. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP Wang, PH (reprint author), SCI & TECHNOL CORP,HAMPTON,VA 23666, USA. OI Thomason, Larry/0000-0002-1902-0840 NR 25 TC 26 Z9 26 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JAN 20 PY 1996 VL 35 IS 3 BP 433 EP 440 DI 10.1364/AO.35.000433 PG 8 WC Optics SC Optics GA TR972 UT WOS:A1996TR97200012 PM 21069028 ER PT J AU Sellmaier, FH Yamamoto, T Pauldrach, AWA Rubin, RH AF Sellmaier, FH Yamamoto, T Pauldrach, AWA Rubin, RH TI A possible solution for the [Ne III] problem in H II regions SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE H II regions; ultraviolet, stars; stars, atmospheres; stars, early type; stars, mass-loss ID INCLUDING SPHERICAL EXTENSION; MODEL ATMOSPHERES; ORION NEBULA; STELLAR WINDS; STARS AB By means of realistic model atmospheres for O-type stars, we investigate the influence of EUV radiation on the ionization structure of H II regions. Our model calculations are based on a detailed multilevel NLTE treatment including radiation-driven wind theory and a consistent calculation of NLTE line blocking opacities for all contributing ionization stages. This is especially important since the spectral distribution of our ionizing fluxes is mainly influenced by the two partly compensating processes of (i) metal line blocking and (ii) the effect of a stellar wind. Even very low mass-loss rates affect the subsonic density structure and, consequently, the emergent flux. By applying our emergent fluxes to a standard nebular code we find, compared to other investigations, an improved match between the observed and calculated ionization structure. In particular, the relatively high ionization fraction of Ne++ is well reproduced by our calculations. Thus, our emergent ionizing fluxes provide a solution to the persistent [Ne III] problem in HII regions. In addition, the fractions of O++ and S++ are changed with the consequence that the relation between the ratio O++/S++ and the temperature of the ionizing source is modified. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Sellmaier, FH (reprint author), INST ASTRON & ASTROPHYS, SCHEINERSTR 1, D-81679 MUNICH, GERMANY. NR 25 TC 36 Z9 36 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 JAN 20 PY 1996 VL 305 IS 3 BP L37 EP L40 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TR769 UT WOS:A1996TR76900003 ER PT J AU Dwek, E Foster, SM Vancura, O AF Dwek, E Foster, SM Vancura, O TI Cooling, sputtering, and infrared emission from dust grains in fast nonradiative shocks SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared, ISM, continuum; radiation mechanisms, thermal; shock waves ID TEMPERATURE-FLUCTUATIONS; INTERSTELLAR GRAINS; SUPERNOVA REMNANT; CYGNUS LOOP; HOT GAS; X-RAY; DESTRUCTION; PLASMAS; SOLAR; WAVES AB We model the dynamics, the destruction by sputtering, and the infrared (IR) emission from collisionally heated dust grains in fast (greater than or equal to 400 km s(-1)) astrophysical shocks in order to develop IR diagnostics for the destruction of grains in these environments. The calculations take into account the feedback from sputtering and IR emission on the gas-phase abundances, the cooling, and the ionization and thermal structure of the shock. Sputtering changes the initial grain size distribution, creating a deficiency of small (radius < 50 Angstrom) grains compared to their preshock abundances. The altered grain size distribution depends on shock velocity and the density of the interstellar medium. Dust particles with sizes below approximate to 300 Angstrom are stochastically heated, undergo temperature fluctuations, and radiate an excess of near-infrared emission (lambda less than or equal to 40 mu m) over that expected for grains in thermal equilibrium. This near-infrared excess is a measure of the abundance of small grains and therefore a powerful diagnostic for the amount of destruction the grains were subjected to in the shock. We present here IR spectra from collisionally heated dust for a variety of shocks, and depict the changes in the spectra as a function of postshock column density. Our studies compliment those of Vancura et al. that examined the effects of the release of the sputtered refractory elements on the ultraviolet and X-ray emission. Multiwavelength observations at X-ray, UV, and IR wavelengths are therefore essential in piecing together a comprehensive picture of the physics of grain destruction in fast astrophysical shocks. C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. CTR ASTROPHYS,CAMBRIDGE,MA 02138. RP Dwek, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INFRARED ASTROPHYS BRANCH,CODE 685,GREENBELT,MD 20771, USA. NR 33 TC 54 Z9 54 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 JAN 20 PY 1996 VL 457 IS 1 BP 244 EP 252 DI 10.1086/176725 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP705 UT WOS:A1996TP70500019 ER PT J AU deJager, OC Harding, AK Michelson, PF Nei, HI Nolan, PL Sreekumar, P Thompson, DJ AF deJager, OC Harding, AK Michelson, PF Nei, HI Nolan, PL Sreekumar, P Thompson, DJ TI Gamma-ray observations of the Crab Nebula: A study of the synchro-Compton spectrum SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, observations; ISM, individual (Crab Nebula); ISM, magnetic fields; MHD; radiation mechanisms, nonthermal; X-rays, ISM ID HIGH-ENERGY; X-RAY; PULSAR; WINDS AB Phase I and II EGRET observations of the Crab Nebula establish the synchro-Compton unpulsed spectrum between approximately 70 MeV and 30 GeV. The soft 70-150 MeV spectrum appears to be a steepened extension of the 1-30 MeV COMPTEL spectrum recently reported by Much et al., indicating that the nebular synchrotron spectrum cuts off with an e-folding energy E(o) similar to 26 MeV. This energy is consistent with the characteristic synchrotron energy h nu(max) similar to (3/4 pi)(2)hc/r(o) = 25 MeV (with r(o) being the classical electron radius) expected for the synchrotron burnoff if electrons are accelerated on a timescale equal to the electron gyro-period in the inner nebula. The 70-150 MeV emission in the exponential tail of this cutoff decreased by a factor of about 2 between 1991 and 1993, which is consistent with an approximately 25% reduction in E(o) over that time. A steady hard, approximately E(-1.85) photon spectrum, added to the synchrotron component, is required for energies up to 10 GeV. This spectrum steepens toward the observed TeV gamma-ray spectrum and may represent the expected nebular inverse-Compton (IC) component, which allows a measurement of the mean nebular field strength: from EGRET we obtain (B) over bar similar to 0.13 me for the radio nebula, whereas the various reported TeV observations correspond to a larger (B) over bar similar to 0.26 mG for the smaller optical nebula. The observation of the IC component also allows us to obtain a lower limit to the time-averaged injection rate N > 4 x 10(40) s(-1) for all electrons/positrons into the nebula. The combined EGRET/TeV IC spectrum appears to be inconsistent with the assumption of a spherically symmetric particle-dominated pulsar wind with parameter sigma similar to 0.003 (see the work of Kennel & Coroniti). C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. STANFORD UNIV,HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. RP deJager, OC (reprint author), POTCHEFSTROOM UNIV CHRISTIAN HIGHER EDUC,DEPT PHYS,SPACE RES UNIT,POTCHEFSTROOM 2520,SOUTH AFRICA. RI Nolan, Patrick/A-5582-2009; Thompson, David/D-2939-2012; Harding, Alice/D-3160-2012 OI Thompson, David/0000-0001-5217-9135; NR 59 TC 180 Z9 180 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 JAN 20 PY 1996 VL 457 IS 1 BP 253 EP 266 DI 10.1086/176726 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP705 UT WOS:A1996TP70500020 ER PT J AU Ko, YK Lee, YP Schlegel, EM Kallman, TR AF Ko, YK Lee, YP Schlegel, EM Kallman, TR TI Modeling emission lines from dwarf novae in quiescence SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line, formation; novae, cataclysmic variables; X-rays, stars ID X-RAY-EMISSION; CATACLYSMIC VARIABLES; ACCRETION DISKS; BOUNDARY-LAYERS; CORONAE; SPECTRA; STARS; UV AB For cataclysmic variables with disk accretion, it is plausible that X-rays/extreme-ultraviolet (EUV) radiation as a result of accretion can back-illuminate the accretion disk. Such illumination will photoionize and heat up the disk to form a temperature-inverted layer in which emission lines can form. We make self-consistent, non-LTE calculations of the vertical structure, ionization, ion level populations, and the emitted spectrum for such photoionized layers. We compare the emerging emission-line spectra with the observations of dwarf novae in quiescence from IUE. We show that a strong soft X-ray/EUV component is necessary to explain the observed UV line strengths. We also explore the possibility of UV line production from disks heated only by viscous dissipation.. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NR 28 TC 18 Z9 18 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 JAN 20 PY 1996 VL 457 IS 1 BP 363 EP 381 DI 10.1086/176736 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP705 UT WOS:A1996TP70500030 ER PT J AU Audley, MD Kelley, RL Boldt, EA Jahoda, KM Marshall, FE Petre, R Serlemitsos, PJ Smale, AP Swank, JH Weaver, KA AF Audley, MD Kelley, RL Boldt, EA Jahoda, KM Marshall, FE Petre, R Serlemitsos, PJ Smale, AP Swank, JH Weaver, KA TI A high-resolution X-ray spectrum of centaurus X-3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE line, identification; pulsars, individual (Centaurus X-3); stars, oscillations; X-rays, stars ID QUASI-PERIODIC OSCILLATIONS; BINARY-SYSTEMS; NEUTRON STARS; IRON LINE; ACCRETION; EMISSION; PULSARS; GINGA AB The high-mass X-ray binary pulsar Centaurus X-3 was observed with the Broad Band X-Ray Telescope (BBXRT) in 1990 December as part of the Astro-1 mission on the Space Shuttle Columbia. During the similar to 1600 s observation, the system was in a high-luminosity postegress state. With an energy resolution of about 150 eV FWHM at 6 keV, the Fe K emission feature was resolved into at least two components. We found a broad (similar to 740 eV FWHM) emission feature at 6.7 keV which is probably a blend of lines from Fe XXI to Fe XXVI due to X-ray photoionization of the stellar wind of the companion. This is the first time the physical width of the 6.7 keV feature has been measured in Cen X-3. We also found evidence for a weak emission line at 6.4 keV with no discernible width, which we attribute to fluorescence of iron in relatively low ionization states. We did not detect pulsations in the iron emission features, but our sensitivity does not rule out the presence of pulsations with 50% amplitude as reported by Day et al. in 1993. We confirm. the presence of quasi-periodic oscillations at about 40 mHz. C1 UNIV MARYLAND, COLLEGE PK, MD 20742 USA. RP Audley, MD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, XRAY ASTROPHYS BRANCH, CODE 662, GREENBELT, MD 20771 USA. RI Swank, Jean/F-2693-2012; Kelley, Richard/K-4474-2012 NR 43 TC 15 Z9 15 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1996 VL 457 IS 1 BP 397 EP 406 DI 10.1086/176739 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP705 UT WOS:A1996TP70500033 ER PT J AU Corbet, RHD AF Corbet, RHD TI Transient X-ray sources, luminosity gaps, and neutron star densities SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, close; equation of state; stars, neutron; X-rays, stars ID GAMMA-CASSIOPEIAE AB A simple model of accretion onto magnetized neutron stars predicts a large luminosity change during a transition from magnetospheric accretion to neutron star accretion. It is pointed out that, for this model, the ratio of the minimum neutron star accretion luminosity and maximum magnetospheric accretion luminosity depends on just the neutron star density and rotation period. Hence, the detection of such a luminosity gap would, at least in principle, give direct insight into the mass-radius relationship of neutron stars. Some potential problems that may affect this measurement are also discussed and some observational results are briefly reviewed. RP Corbet, RHD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 662,GREENBELT,MD 20771, USA. NR 21 TC 36 Z9 36 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 JAN 20 PY 1996 VL 457 IS 1 BP L31 EP L33 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP706 UT WOS:A1996TP70600008 ER PT J AU Potter, CS Matson, PA Vitousek, PM Davidson, EA AF Potter, CS Matson, PA Vitousek, PM Davidson, EA TI Process modeling of controls on nitrogen trace gas emissions from soils worldwide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TEMPERATE FOREST SOILS; DRY TROPICAL FOREST; OXIDE PRODUCTION; NITRIC-OXIDE; GASEOUS NITROGEN; UNITED-STATES; N2O; DENITRIFICATION; ECOSYSTEMS; ATMOSPHERE AB We report on an ecosystem modeling approach that integrates global satellite, climate, vegetation, and soil data sets to (1) examine conceptual controls on nitrogen trace gas (NO, N2O, and N-2) emissions from soils and (2) identify weaknesses in our bases of knowledge and data for these fluxes. Nitrous and nitric oxide emissions from well-drained soils were estimated by using an expanded version of the Carnegie-Ames-Stanford (CASA) Biosphere model, a coupled ecosystem production and soil carbon-nitrogen model on a 1 degrees global grid. We estimate monthly production of NO, N2O, and N-2 based on predicted rates of gross N mineralization, together with an index of transient water-filled pore space in soils. Analyses of model performance along selected climate gradients support the hypothesis that low temperature restricts predicted N mineralization and trace gas emission rates in moist northern temperate and boreal forest ecosystems, whereas in tropical zones, seasonal patterns in N mineralization result in emission peaks for N2O that coincide with wetting and high soil moisture content. The model predicts the annual N2O:NO flux ratio at a mean value of 1.2 in wet tropical forests, decreasing to around 0.6 in the seasonally dry savannas. Global emission estimates at the soil surface are 6.1 Tg N and 9.7 Tg N yr(-1) for N2O and NO, respectively, Tropical dry forests and savannas are identified by using this formulation as important source areas for nitrogen trace gas emissions. Because humans continue to alter these ecosystems extensively for agricultural uses, our results suggest that more study is needed in seasonally dry ecosystems of the tropics in order to understand the global impacts of land use change on soil sources for N2O and NO. C1 UNIV CALIF BERKELEY, DEPT ENVIRONM SCI POLICY & MANAGEMENT, BERKELEY, CA USA. STANFORD UNIV, DEPT BIOL SCI, STANFORD, CA 94305 USA. WOODS HOLE RES CTR, WOODS HOLE, MA 02543 USA. RP Potter, CS (reprint author), NASA, AMES RES CTR, ECOSYST SCI & TECHNOL BRANCH, JOHNSON CONTROLS WORLD SERV INC, MAIL STOP 242-4, MOFFETT FIELD, CA 94035 USA. RI Davidson, Eric/K-4984-2013 OI Davidson, Eric/0000-0002-8525-8697 NR 80 TC 227 Z9 237 U1 6 U2 47 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1361 EP 1377 DI 10.1029/95JD02028 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600003 ER PT J AU Douglass, AR Weaver, CJ Rood, RB Coy, L AF Douglass, AR Weaver, CJ Rood, RB Coy, L TI A three-dimensional simulation of the ozone annual cycle using winds from a data assimilation system SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONSTITUENT TRANSPORT CALCULATIONS; REACTIVE CHLORINE; POLAR VORTEX; MODEL; STRATOSPHERE; CONSERVATION; CHEMISTRY; SCHEME AB The wind fields from the NASA Goddard stratospheric data assimilation procedure are used in a three-dimensional chemistry and transport model to produce an ozone simulation for the year September 11, 1991 to September 10, 1992. Photochemical production and loss are taken from the Goddard two-dimensional model. The calculated ozone is compared with observations from the total ozone mapping spectrometer (TOMS) on board Nimbus 7 and the microwave limb sounder on the upper atmospheric research satellite. Although the model total ozone is about 50 Dobson units (DU; = 2.69 x 10(-16) molecules cm(-2)) lower than TOMS in the tropics and up to 70 DU higher than TOMS in middle to high latitudes, the simulated ozone fields reproduce many of the features in the observations. Even at the end of this integration, the synoptic features in the modeled total ozone are very similar to TOMS observations, indicating that the model maintains realistic values for the horizontal and vertical gradients, at least in the lower stratosphere. From this good comparison between model and observations on timescales ranging from days to months, we infer that the transport driven by the assimilated wind fields closely approximates the actual atmospheric transport. Therefore the assimilated winds are useful for applications which may be sensitive to the lower stratospheric transport. C1 APPL RES CORP, LANDOVER, MD 20785 USA. GEN SCI CORP, LAUREL, MD 20707 USA. RP Douglass, AR (reprint author), NASA, GODDARD SPACE FLIGHT CTR, 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 33 TC 66 Z9 66 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1463 EP 1474 DI 10.1029/95JD02601 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600011 ER PT J AU Glaze, LS Baloga, SM AF Glaze, LS Baloga, SM TI Sensitivity of buoyant plume heights to ambient atmospheric conditions: Implications for volcanic eruption columns SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DYNAMICS AB A theoretical model is developed to investigate the sensitivity of buoyant atmospheric plumes to a wide range of ambient atmospheric conditions, including the temperature gradient, the latitude of the source, and the season. The formulation highlights the compressibility of an ideal gas, internal consistency between the governing equations for the conservation of momentum and energy, and the explicit use of the equation of state. Specific results are presented for water vapor plumes and implications are developed for multicomponent (water vapor, silicate particles, and condensates) volcanic plumes, If plume cooling is due solely to adiabatic expansion and the entrainment and mixing of ambient air, then the atmospheric temperature gradient is shown to be a dominant influence on plume height. Changes in the atmospheric gradient of 10 K/km cause the height of a low-level plume to differ by a factor of 2. We estimate the magnitude of this effect on volcanic plumes by considering water vapor erupted with equivalent heat fluxes. The sensitivity of plumes to ambient conditions is a result of the small density difference driving buoyancy. The plume density, in turn, is strongly controlled by the thermal energy of the system. Sensitivities associated with the thermal energy balance in the eruption column are also investigated. A modest thermal loss (1-2%/km) from the column by a process other than entrainment can result in a plume height significantly lower than one that cools by entrainment alone. Additional cooling of this magnitude could be caused by a variety of combinations of phenomena, including radiative heat loss and, possibly, the conversion of heat energy into turbulent rotational energy. For particle-laden plumes, there is the possibility of additional heat loss through the fallout of solids from the eruption column. To understand the details of the thermal energy balance in a plume, measurements must be made of the bulk plume temperature profile under known atmospheric conditions. C1 PROXEMY RES INC, LAYTONSVILLE, MD 20882 USA. RP Glaze, LS (reprint author), NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, CODE 921, GREENBELT, MD 20771 USA. RI Glaze, Lori/D-1314-2012 NR 14 TC 55 Z9 57 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1529 EP 1540 DI 10.1029/95JD03071 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600016 ER PT J AU Jonsson, HH Wilson, JC Brock, CA Dye, JE Ferry, GV Chan, KR AF Jonsson, HH Wilson, JC Brock, CA Dye, JE Ferry, GV Chan, KR TI Evolution of the stratospheric aerosol in the northern hemisphere following the June 1991 volcanic eruption of Mount Pinatubo: Role of tropospheric-stratospheric exchange and transport SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ANTARCTIC OZONE EXPERIMENT; CONDENSATION NUCLEI; PARTICLE FORMATION; SULFATE AEROSOL; CLOUD FORMATION; POLAR VORTEX; EL-CHICHON; CHEMISTRY; CHLORINE; SO2 AB Since the eruption of Mount Pinatubo in June, 1991, measurements of particle size and concentration have intermittently been carried out from an ER-2 aircraft at altitudes of up to 21 km at midlatitudes and high latitudes in the northern hemisphere. They show the evolution and purge of the volcanic aerosol to be due to an interaction of aerosol mechanics with tropospheric-stratospheric exchange processes, transport, and mixing. During the first 5 months after the eruption the volcanic plume spread to higher latitudes in laminae and filaments, producing steep spatial gradients in the properties of the stratospheric aerosol. At the same time the concentration of newly formed particles in the plume rapidly decreased toward background values as a result of coagulation while particle size and aerosol surface area continued to increase. By December 1991, the particle number mixing ratios and aerosol surface area mixing ratios had become spatially uniform over a wide range of latitudes above 18 km. The surface area mixing ratios peaked in this region of the stratosphere at similar to 35 times their background values in the winter of 1992. The corresponding condensed mass mixing ratio enhancement was by a factor of similar to 200. After the winter of 1992, a gradual removal of the volcanic mass began and initially was dominated by sedimentation above 18 km. The aerosol surface area mixing ratio thus decreased by an order of magnitude over 2.5 years, and the aerosol volume, or condensed mass, mixing ratio decayed by an order of magnitude over approximately 1.7 years. Below 18 km, the purging of the Pinatubo aerosol at mid-latitudes appeared sporadic and disorderly and was strongly influenced by episodal rapid quasi-isentropic transport and dilution by tropical air of tropospheric origin having high condensation nuclei mixing ratios but low mixing ratios of aerosol surface area or condensed mass compared to the volcanic aerosol. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Jonsson, HH (reprint author), UNIV DENVER, DEPT ENGN, DENVER, CO 80208 USA. RI Brock, Charles/G-3406-2011 OI Brock, Charles/0000-0002-4033-4668 NR 40 TC 9 Z9 9 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1553 EP 1570 DI 10.1029/95JD02932 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600018 ER PT J AU Hoell, JM Davis, D Liu, SC Newell, R Shipham, M Akimoto, H McNeal, RJ Bendura, RJ Drewry, JW AF Hoell, JM Davis, D Liu, SC Newell, R Shipham, M Akimoto, H McNeal, RJ Bendura, RJ Drewry, JW TI Pacific exploratory Mission-West A (PEM-West A): September October 1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The NASA Pacific Exploratory Mission-West (PEM-West) is a major component of the East Asia/North Pacific Regional Study (APARE), a project within the International Global Atmospheric Chemistry (IGAC) program. The broad objective of the PEM-West/APARE initiative is to study chemical processes and long-range transport over the northwestern Pacific Ocean and to estimate the magnitude of the human impact on the oceanic atmosphere over this region particularly for tropospheric ozone and its precursors as well as for sulfur species, The first phase of this mission, PEM-West A, was conducted during September-October 1991. The PEM-West A included intensive airborne measurements of trace gases from the NASA DC-8 aircraft coordinated with measurements at PEM-West A surface sites as well as with measurements obtained from; collaborating APARE ground and airborne platforms. This paper reports the experimental design for PEM-West A with a brief summary of the general content and focus of companion papers in this special issue. C1 GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. MIT, CAMBRIDGE, MA 02139 USA. NASA, WASHINGTON, DC 20546 USA. RP Hoell, JM (reprint author), NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NR 43 TC 176 Z9 179 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1641 EP 1653 DI 10.1029/95JD00622 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600024 ER PT J AU Bachmeier, AS Newell, RE Zhu, Y Blake, DR Browell, EV AF Bachmeier, AS Newell, RE Zhu, Y Blake, DR Browell, EV TI PEM-West A: Meteorological overview SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC AB Phase A of the NASA Pacific Exploratory Mission in the western North Pacific (PEM-West A) region was conducted during September-October 1991. The background meteorology of eastern Asia and the western North Pacific region during the PEM-West A study is described. Mean large-scale flow patterns are discussed along with transient synoptic scale features (e.g., midlatitude cyclones, anticyclones, and frontal systems) responsible for long-range transport of trace species over the study region. Synoptic summaries are given for each of the 18 data flights, together with selected examples of meteorological processes that gave rise to some of the changes observed in the measured trace gases, Examples of large-scale ozone features observed above and below the DC-8 flight altitude by an onboard lidar system are also related to meteorological processes such as stratospheric-tropospheric exchange and upward transport of air from the boundary layer. C1 MIT, CAMBRIDGE, MA 02138 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. RP Bachmeier, AS (reprint author), LOCKHEED ENGN & SCI CO, 144 RES DR, HAMPTON, VA 23666 USA. NR 20 TC 38 Z9 38 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1655 EP 1677 DI 10.1029/95JD02799 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600025 ER PT J AU Browell, EV Fenn, MA Butler, CF Grant, WB Merrill, JT Newell, RE Bradshaw, JD Sandholm, ST Anderson, BE Bandy, AR Bachmeier, AS Blake, DR Davis, DD Gregory, GL Heikes, BG Kondo, Y Liu, SC Rowland, FS Sachse, GW Singh, HB Talbot, RW Thornton, DC AF Browell, EV Fenn, MA Butler, CF Grant, WB Merrill, JT Newell, RE Bradshaw, JD Sandholm, ST Anderson, BE Bandy, AR Bachmeier, AS Blake, DR Davis, DD Gregory, GL Heikes, BG Kondo, Y Liu, SC Rowland, FS Sachse, GW Singh, HB Talbot, RW Thornton, DC TI Large-scale air mass characteristics observed over western Pacific during summertime SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE; PROFILES; AEROSOLS; OCEAN; GAMETAG; LIDAR; GASES AB Remote and in situ measurements of gases and aerosols were made with airborne instrumentation to investigate the sources and sinks of tropospheric gases and aerosols over the western Pacific during the NASA Global Tropospheric Experiment (GTE)/Pacific Exploratory Mission-West A (PEM-West A) conducted in September-October 1991. This paper discusses the general characteristics of the air masses encountered during this experiment using an airborne lidar system for measurements of the large-scale variations in ozone (O-3) and aerosol distributions across the troposphere and airborne in situ instrumentation for comprehensive measurements of air mass composition, In low latitudes of the western Pacific the airflow was generally from the east, and under these conditions the air was observed to have low aerosol loading and low ozone levels throughout the troposphere. Ozone was found to be below 10 parts per billion volume (ppbv) near the surface to 40-50 ppbv in the middle to upper troposphere, In the middle and high latitudes the airflow was mostly westerly, and the background O-3 was generally less than 55 ppbv. On 60% of the PEM-West A flights, O-3 was observed to exceed these levels in regions that were determined to be associated with stratospheric intrusions, In convective outflows from typhoons, near-surface air with low ozone (<25 ppbv) was transported into the upper troposphere (>10 km). Several cases of continental plumes from Asia were observed over the Pacific during westerly flow conditions. These plumes were found in the lower troposphere with ozone levels in the 60-80 ppbv range and enhanced aerosol scattering. At low latitudes over the central Pacific the troposphere primarily contained air with background or low ozone levels; however, stratospherically influenced air with enhanced ozone (40-60 ppbv) was observed several times in the lower troposphere, The frequency of observation of the air masses and their average chemical composition are also discussed in this paper. C1 UNIV CALIF IRVINE, IRVINE, CA 92714 USA. DREXEL UNIV, PHILADELPHIA, PA 19104 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. SCI APPLICAT INT CORP, HAMPTON, VA 23666 USA. NAGOYA UNIV, TOYOKAWA, AICHI, JAPAN. NOAA, AERON LAB, BOULDER, CO 80303 USA. MIT, CAMBRIDGE, MA 02139 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. UNIV RHODE ISL, NARRAGANSETT, RI 02882 USA. RP Browell, EV (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL STOP 401A, HAMPTON, VA 23681 USA. RI Kondo, Yutaka/D-1459-2012; Grant, William/B-8311-2009 OI Grant, William/0000-0002-1439-3285 NR 37 TC 70 Z9 70 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1691 EP 1712 DI 10.1029/95JD02200 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600027 ER PT J AU Talbot, RW Dibb, JE Klemm, KI Bradshaw, JD Sandholm, ST Blake, DR Sachse, GW Collins, J Heikes, BG Gregory, GL Anderson, BE Singh, HB Thornton, DC Merrill, JT AF Talbot, RW Dibb, JE Klemm, KI Bradshaw, JD Sandholm, ST Blake, DR Sachse, GW Collins, J Heikes, BG Gregory, GL Anderson, BE Singh, HB Thornton, DC Merrill, JT TI Chemical characteristics of continental outflow from Asia to the troposphere over the western Pacific Ocean during September October 1991: Results from PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL NORTH PACIFIC; TEMPORAL VARIABILITY; ATMOSPHERIC TRANSPORT; TRACE GASES; EMISSIONS; AEROSOLS; ENEWETAK; AIR; METHANE; PB-210 AB An important objective of the Pacific Exploratory Mission-West A (PEM-West A) was the chemical characterization of the outflow of tropospheric trace gases and aerosol particles from the Asian continent over the western Pacific Ocean. This paper summarizes the chemistry of this outflow during the period September - October 1991. The vertical distributions of CO, C2H6, and NOX showed regions of outflow at altitudes below 2 km and from 8 to 12 km. Mixing ratios of CO were approximate to 130 parts per billion by volume (ppbv), approximate to 1000 parts per trillion by volume (pptv) for C2H6, and approximate to 100 pptv for NOX in both of these regions. Direct outflow of Asian industrial materials was clearly evident at altitudes below 2 lan, where halocarbon tracer compounds such as CH3CCl3 and C2Cl4 were enhanced about threefold compared to aged Pacific air. The source attribution of species outflowing from Asia to the Pacific at 8-12 km altitude was not straightforward. Above 10 km altitude there were substantial enhancements of NOy, O-3, CO, CH4 SO2, C2H6, C3H8, C2H2, and aerosol Pb-210 but not halocarbon industrial tracers. These air masses were rich in nitrogen relative to sulfur and contained ratios of C2H2/CO and C3H8/C2H6 (approximate to 1.5 and 0.1 respectively) indicative of several-day-old combustion emissions. It is unclear if these emissions were of Asian origin, or if they were rapidly transported to this region from Europe by the high wind speeds in this tropospheric region (60 - 70 m s(-1)). The significant cyclonic activity over Asia at this time could have transported to the upper troposphere emissions from biomass burning in Southeast Asia or emissions from the extensive use of various biomass materials for cooking and space heating. Apparently, the emissions in the upper troposphere were brought there by wet convective systems since water-soluble gases and aerosols were depleted in these air masses, Near 9 km altitude there was a distinct regional outflow that appeared to be heavily influenced by biogenic processes on the Asian continent, especially from the southeastern area. These air masses contained CH4 in excess of 1800 ppbv, while CO2 and OCS were significantly depleted (349 - 352 ppmv and 450 - 500 pptv, respectively). This signature seemingly reflected CH4 emissions from wetlands and rice paddies with coincident biospheric uptake of tropospheric CO2 and OCS. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92715 USA. GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. UNIV RHODE ISL, CTR ATMOSPHER CHEM, NARRAGANSETT, RI 02882 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. DREXEL UNIV, DEPT CHEM, PHILADELPHIA, PA 19104 USA. RP Talbot, RW (reprint author), UNIV NEW HAMPSHIRE, COMPLEX SYST RES CTR, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. NR 45 TC 72 Z9 72 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1713 EP 1725 DI 10.1029/95JD01044 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600028 ER PT J AU Gregory, GL Bachmeier, AS Blake, DR Heikes, BG Thornton, DC Bandy, AR Bradshaw, JD Kondo, Y AF Gregory, GL Bachmeier, AS Blake, DR Heikes, BG Thornton, DC Bandy, AR Bradshaw, JD Kondo, Y TI Chemical signatures of aged Pacific marine air: Mixed layer and free troposphere as measured during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EL-NINO; PHOTOCHEMISTRY; ATMOSPHERE; HYDROCARBON; CHEMISTRY; CLOUD; FLUX; CO2 AB The Pacific Ocean is one of the few remaining regions of the northern hemisphere that is relatively free of direct anthropogenic emissions. However, long-range transport of air pollutants is beginning to have a significant impact on the atmosphere over the Pacific. In September and October 1991, NASA conducted the Pacific Exploratory Mission-West A expedition to study the atmospheric chemistry and background budgets of key atmospheric trace species, Aircraft sampling centered on the northern Pacific, 0 degrees to 40 degrees N and 115 degrees to 180 degrees E. The paper summarizes the chemical signature of relatively well-aged Pacific marine air(residence time greater than or equal to 10 days over the ocean), The chemical signatures show that marine air is not always devoid of continental influences. Aged marine air which circulates around the semipermanent subtropical anticyclone located off the Asian continent is influenced by infusion of continental air with anthropogenic emissions. The infusion occurs as the result of Asian outflow swept off the continent behind eastward moving cold fronts. When compared to aged marine air with a more southerly pathway, this infusion results in enhancements in the mixing ratio of many anthropogenic/continental species and typically those with lifetimes of weeks in the free troposphere. Less enhancement is seen for the short-lived species with lifetimes of a few days as infused continental emissions are depleted during transport (about a week) around the semipermanent subtropical high. C1 LOCKHEED ENGN & SCI CO, HAMPTON, VA 23665 USA. DREXEL UNIV, DEPT CHEM, PHILADELPHIA, PA 19104 USA. UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. UNIV RHODE ISL, CTR ATMOSPHER CHEM STUDIES, NARRAGANSETT, RI 02882 USA. NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA, AICHI, JAPAN. RP Gregory, GL (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. RI Kondo, Yutaka/D-1459-2012 NR 37 TC 59 Z9 59 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1727 EP 1742 DI 10.1029/95JD00410 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600029 ER PT J AU Smyth, S Bradshaw, J Sandholm, S Liu, S McKeen, S Gregory, G Anderson, B Talbot, R Blake, D Rowland, S Browell, E Fenn, M Merrill, J Bachmeier, S Sachse, G Collins, J Thornton, D Davis, D Singh, H AF Smyth, S Bradshaw, J Sandholm, S Liu, S McKeen, S Gregory, G Anderson, B Talbot, R Blake, D Rowland, S Browell, E Fenn, M Merrill, J Bachmeier, S Sachse, G Collins, J Thornton, D Davis, D Singh, H TI Comparison of free tropospheric western Pacific air mass classification schemes for the PEM-West A experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE PRODUCTION; NOX; DISTRIBUTIONS; EMISSIONS; NITROGEN AB During September/October 1991, NASA's Global Tropospheric Experiment (GTE) conducted an airborne field measurement program (PEM-West A) in the troposphere over the western Pacific Ocean. In this paper we describe and use the relative abundance of the combustion products C2H2 and CO to classify air masses encountered during PEM-West A based on the degree that these tracers were processed by the combined effects of photochemical reactions and dynamical mixing (termed the degree of atmospheric processing). A large number of trace compounds (e.g., C2H6, C3H8, C6H6, NOy, and O-3) are found to be well correlated with the degree of atmospheric processing that is reflected by changes in the ratio of C2H2/CO over the range of values from similar to 0.3 to 2.0 (parts per trillion volume) C2H2/ (parts per billion volume) CO. This C2H2/CO-based classification scheme is compared to model simulations and to two independent classification schemes based on air mass back-trajectory analyses and lidar profiles of O-3 and aerosols. In general, these schemes agree well, and in combination they suggest that the functional dependence that other observed species exhibit with respect to the C2H2/CO atmospheric processing scale can be used to study the origin, sources, and sinks of trace species and to derive several important findings. First, the degree of atmospheric processing is found to be dominated by dilution associated with atmospheric mixing, which is found to primarily occur through the vertical mixing of relatively recent emissions of surface layer trace species. Photochemical reactions play their major role by influencing the background concentrations of trace species that are entrained during the mixing (i.e., dilution) process. Second, a significant noncontinental source(s) of NO (and NOx) in the free troposphere is evident. In particular, the enhanced NO mixing ratios that were observed in convected air masses are attributed to either emissions from lightning or the rapid recycling of NOy compounds. Third, nonsoluble trace species emitted in the continental boundary layer, such as CO and hydrocarbons, are vertically transported to the upper troposphere as efficiently as they are td the midtroposphere. In addition, the mixing ratios of CO and hydrocarbons in the upper troposphere over the western Pacific may reflect a significant contribution from northern hemisphere land areas other than Asia. Finally, we believe that these results can be valuable for the quantitative evaluation of the vertical transport processes that are usually parameterized in models. C1 NOAA, AERON LAB, BOULDER, CO 80303 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92717 USA. SCI APPLICAT INT CORP, HAMPTON, VA 23681 USA. UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER CHEM STUDIES, NARRAGANSETT, RI 02882 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23681 USA. DREXEL UNIV, DEPT CHEM, PHILADELPHIA, PA 19104 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Smyth, S (reprint author), GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. RI McKeen, Stuart/H-9516-2013 NR 32 TC 71 Z9 71 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1743 EP 1762 DI 10.1029/95JD02861 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600030 ER PT J AU Dibb, JE Talbot, RW Klemm, KI Gregory, GL Singh, HB Bradshaw, JD Sandholm, ST AF Dibb, JE Talbot, RW Klemm, KI Gregory, GL Singh, HB Bradshaw, JD Sandholm, ST TI Asian influence over the western North Pacific during the fall season: Inferences from lead 210, soluble ionic species and ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LOWER TROPICAL STRATOSPHERE; TROPOSPHERIC AIR; TRANSPORT; AIRCRAFT; PB-210; BERYLLIUM-7; ATMOSPHERE; AEROSOLS; RN-222; DUST AB Aerosol samples collected over the western Pacific during the NASA/Global Tropospheric Experiment Pacific Exploratory Mission (PEM-West A) expedition (September October 1991) revealed mean Pb-210 concentrations in the free troposphere in the 5 - 10 fCi m(-3) STP range. Most soluble ionic aerosol-associated species were near detection limits [<< 40 parts per trillion by volume (pptv)] in these same samples. The altitude distribution of O-3 near Asia closely resembled that of Pb-210, while no relationship was found between the concentrations of O-3 and Be-7. Free tropospheric air over the western Pacific was depleted in soluble aerosol-associated species but enriched in Pb-210 and O-3, indicative of deep wet convection over the Asian continent. The influence of Asian air on the composition of the free troposphere over the western Pacific was evident on most of the PEM-West A flights. However, evidence of continental influence was largely restricted to those species that are relatively insoluble (or have insoluble precursors), hence escape scavenging during vertical transport from the boundary layer into the free troposphere by wet convective activity. C1 GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Dibb, JE (reprint author), UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, MORSE HALL, 39 COLL RD, DURHAM, NH 03824 USA. NR 41 TC 52 Z9 52 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1779 EP 1792 DI 10.1029/94JD03117 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600032 ER PT J AU Singh, HB Herlth, D Kolyer, R Salas, L Bradshaw, JD Sandholm, ST Davis, DD Crawford, J Kondo, Y Koike, M Talbot, R Gregory, GL Sachse, GW Browell, E Blake, DR Rowland, FS Newell, R Merrill, J Heikes, B Liu, SC Crutzen, PJ Kanakidou, M AF Singh, HB Herlth, D Kolyer, R Salas, L Bradshaw, JD Sandholm, ST Davis, DD Crawford, J Kondo, Y Koike, M Talbot, R Gregory, GL Sachse, GW Browell, E Blake, DR Rowland, FS Newell, R Merrill, J Heikes, B Liu, SC Crutzen, PJ Kanakidou, M TI Reactive nitrogen and ozone over the western Pacific: Distribution, partitioning, and sources SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; CONTINENTAL UNITED-STATES; PEROXYACETYL NITRATE PAN; UPPER TROPOSPHERE; EASTERN PACIFIC; NITRIC-ACID; NOX; IMPACT; MODEL; HNO3 AB Measurements of important reactive nitrogen species (NO, NO2, HNO3, PAN, PPN, NO3-, NOy), C-1 to C-6 hydrocarbons, O-3, chemical tracers (C2Cl4, CO), and meteorological parameters were made in the troposphere (0 to 12 km) over the western Pacific (0 degrees-50 degrees N) during the Pacific Exploratory Mission-West A campaign (September-October 1991). Under clean conditions, mixing ratios of NO, NO2, NOy, and O-3 increased with altitude and showed a distinct latitudinal gradient. PAN showed a midtropospheric maximum, while nitric acid mixing ratios were generally highest near the surface. Measured NOy concentrations were significantly greater than the sum of individually measured nitrogen species (mainly NOx, PAN, and HNO3), suggesting that a large fraction of reactive nitrogen present in the atmosphere is made up of hitherto unknown species. This shortfall was larger in the tropics (approximate to 65%) compared to midlatitudes (approximate to 40%) and was minimal in air masses with high HNO3 mixing ratios (>100 ppt). A global three-dimensional photochemical model has been used to compare observations with predictions and to assess the significance of major sources. It is possible that the tropical lightning source is much greater than commonly assumed, and both lightning source and its distribution remain a major area of uncertainty in the budgets of NOy and NOx. A large disagreement between measurement and theory exists in the atmospheric distribution of HNO3. It appears that surface-based anthropogenic emissions provide nearly 65% of the global atmospheric NOy reservoir. Relatively constant NOx/NOy ratios imply that NOy and NOx are in chemical equilibrium and the NOy reservoir may be an important in situ source of atmospheric NOx. Data are interpreted to suggest that only about 20% of the upper tropospheric (7-12 km) NOx is directly attributable to its surface NOx source, and free tropospheric sources are dominant. In situ release of NOx from the NOy reservoir, lightning, direct transport of surface NOx, aircraft emissions, and small stratospheric input collectively maintain the NOx balance in the atmosphere. It is shown that atmospheric ratios of reactive nitrogen and sulfur species, along with trajectory analysis, can be used to pinpoint the source of Asian continental outflow. Compared to rural atmospheres over North America, air masses over the Pacific are highly efficient in net O-3 production. Sources of tropospheric NOx cannot yet be accurately defined due to shortcomings in measurements and theory. C1 UNIV CALIF IRVINE, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. MAX PLANCK INST CHEM, D-55020 MAINZ, GERMANY. UNIV RHODE ISL, NARRAGANSETT, RI 02882 USA. CEA, CNRS, LAB MIXTE, CTR FAIBLES RADIOACT, F-91198 GIF SUR YVETTE, FRANCE. NAGOYA UNIV, TOYOKAWA, AICHI, JAPAN. NOAA, AERON LAB, BOULDER, CO 80303 USA. MIT, CAMBRIDGE, MA 02139 USA. SAN JOSE STATE UNIV FDN, MOFFETT FIELD, CA 94035 USA. UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. RP Singh, HB (reprint author), NASA, AMES RES CTR, CODE 245-5, MOFFETT FIELD, CA 94035 USA. RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012; Kanakidou, Maria/D-7882-2012; Crutzen, Paul/F-6044-2012; Crawford, James/L-6632-2013 OI Kanakidou, Maria/0000-0002-1724-9692; Crawford, James/0000-0002-6982-0934 NR 45 TC 129 Z9 132 U1 2 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1793 EP 1808 DI 10.1029/95JD01029 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600033 ER PT J AU Kondo, Y Ziereis, H Koike, M Kawakami, S Gregory, GL Sachse, GW Singh, HB Davis, DD Merrill, JT AF Kondo, Y Ziereis, H Koike, M Kawakami, S Gregory, GL Sachse, GW Singh, HB Davis, DD Merrill, JT TI Reactive nitrogen over the Pacific Ocean during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NITRIC-OXIDE; FREE TROPOSPHERE; ODD-NITROGEN; AIRCRAFT MEASUREMENTS; OZONE PRODUCTION; EASTERN PACIFIC; BOUNDARY-LAYER; UNITED-STATES; NOX; AIR AB Measurements of NO and NOy were carried out during NASA's Pacific Exploratory Mission-West A. In total, 18 aircraft flights were made over the Pacific Ocean, predominantly over the western Pacific Ocean in September and October 1991. NO and NOy were measured using a chemiluminescence instrument, and NOx was calculated from NO using a chemical box model. The measurements were carried out from 0.3 to 12 km in altitude. The NO, calculated NOx ((NOx)(mc)), and NOy mixing ratios in continental air were significantly higher than in maritime air. In maritime air, NO increased with altitude. The median values of NO in the boundary layer and the lower, middle; and upper troposphere were 3.7, 5.1, 11.5, and 26.6 parts per trillion by volume (pptv), respectively. In continental air, NO and (NOx)(mc) mixing ratios revealed a C-shaped profile. The median NO values observed in the four altitude regions were 37.8, 17.5, 18.2, and 53.2 pptv, respectively. NOy did not show any apparent altitude dependence either in maritime or in continental air. In maritime air, median NOy values in the lower, middle, and upper troposphere ranged between 211 and 226 pptv and in continental air between 382 and 401 pptv. The lowest values of NOy, PAN, and O-3 were observed in tropical air masses throughout the entire altitude region. In the middle and upper troposphere of the high-latitude air masses, NO and (NOx)(mc) values were the lowest, although NOy mixing ratios were similar to those in continental air masses. PAN, O-3, CO, CH4, and C2H6 data were used to study the budget of reactive nitrogen over the Pacific Ocean. O-3 mixing ratios were found to be correlated with those of (NOx)(mc), NOy, PAN, and CH4, although the degree of correlation varied with air mass and altitude. These correlations, together with the profiles of these species, suggest that photochemical production of O-3 from precursor species over the continent is important for the O-3 budget in the troposphere over, the western Pacific Ocean. C1 GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER CHEM STUDIES, NARRAGANSETT, RI 02882 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. DLR, INST PHYS ATMOSPHARE, D-82234 WESSELING, GERMANY. RP Kondo, Y (reprint author), NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA, AICHI 442, JAPAN. RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012 NR 53 TC 54 Z9 54 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1809 EP 1828 DI 10.1029/95JD02611 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600034 ER PT J AU Koike, M Kondo, Y Kawakami, S Singh, HB Ziereis, H Merrill, JT AF Koike, M Kondo, Y Kawakami, S Singh, HB Ziereis, H Merrill, JT TI Ratios of reactive nitrogen species over the Pacific during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; CONTINENTAL UNITED-STATES; OZONE PRODUCTION; PEROXYACETYL NITRATE; TROPOSPHERIC OZONE; ORGANIC NITRATES; EASTERN PACIFIC; NIWOT RIDGE; AIR MASSES; NOX AB Measurements of total reactive odd nitrogen (NOy) and known individual odd nitrogen species were made over the Pacific Ocean in September and October 1991 during the NASA Global Tropospheric Experiment, Pacific Exploratory Mission-West A (GTE/PEM-West A). The ratios between NOx (NO + NO2) calculated from observed NO assuming photochemical equilibrium ((NOx)(mc)), peroxyacetyl nitrate (PAN), and NOy have been investigated for these data. The mixing ratios of(NOx)(mc), PAN, and NOy in the lower and middle troposphere generally decreased with the air mass age, which has been defined by the propane/ethane ratio (C3H8/C2H6). The (NOx)(mc)/NOy ratios in the continental air showed a C-shaped vertical profile and median values were 0.27, 0.11, and 0.20 in the lower, middle, and upper troposphere, respectively. In the maritime and tropical air the (NOx)(mc)/NOy ratios generally increased with altitude and were about 0.1 and 0.15 in the lower and upper troposphere, respectively. In the middle troposphere the (NOx)(mc)/NOy ratios were similar in continental, maritime, and tropical air. These results are consistent with the fact that the (NOx)(mc)/NOy ratio did not decrease with the air mass age in the middle troposphere, suggesting the existence of NOx sources in the free troposphere. The PAN/NOy ratios in the continental air were about 0.3 at all altitudes. In maritime and tropical air the PAN/NOy ratio increased sharply at altitudes between 3 and 5 km with values of about 0.03 below 3 km and between 0.1 and 0.2 in the middle and upper troposphere. The PAN/NOy ratio generally decreased with the air mass age in;the middle troposphere. In spite of a longer photochemical lifetime of PAN than NOx the PAN/(NOx)(mc) ratio also generally decreased with air mass age. These observations indicate that the reactive nitrogen ratios in the continental air mass are influenced by anthropogenic emissions at all altitudes, although relative contributions from various NOx sources in the upper troposphere are still poorly understood. Some influence from the continental air can be seen in the anthropogenic origin species in the maritime air mass when compared with the tropical air mass (Kondo et al., this issue). Similar (NOx)(mc)/NOy ratios, however, were generally found between the maritime and tropical air masses and a difference was only seen in the slightly higher PAN/NOy ratios in the maritime middle tropospheric air. The high-latitude air is characterized by low (NOx)(mc)/NOy ratios and high PAN/(NOx)(mc) ratios, probably due to the low atmospheric temperatures. C1 UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER CHEM STUDIES, NARRAGANSETT, RI 02882 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. DLR, INST PHYS ATMOSPHARE, WESSELING, GERMANY. RP Koike, M (reprint author), NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, 3-13 HONOHARA, TOYOKAWA, AICHI 442, JAPAN. RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012 NR 48 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1829 EP 1851 DI 10.1029/95JD02728 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600035 ER PT J AU Newell, RE Hu, W Wu, ZX Zhu, Y Akimoto, H Anderson, BE Browell, EV Gregory, GL Sachse, GW Shipham, MC Bachmeier, AS Bandy, AR Thornton, DC Blake, DR Rowland, FS Bradshaw, JD Crawford, JH Davis, DD Sandholm, ST Brockett, W DeGreef, L Lewis, D McCormick, D Monitz, E Collins, JE Heikes, BG Merrill, JT Kelly, KK Liu, SC Kondo, Y Koike, M Liu, CM Sakamaki, F Singh, HB Dibb, JE Talbot, RW AF Newell, RE Hu, W Wu, ZX Zhu, Y Akimoto, H Anderson, BE Browell, EV Gregory, GL Sachse, GW Shipham, MC Bachmeier, AS Bandy, AR Thornton, DC Blake, DR Rowland, FS Bradshaw, JD Crawford, JH Davis, DD Sandholm, ST Brockett, W DeGreef, L Lewis, D McCormick, D Monitz, E Collins, JE Heikes, BG Merrill, JT Kelly, KK Liu, SC Kondo, Y Koike, M Liu, CM Sakamaki, F Singh, HB Dibb, JE Talbot, RW TI Atmospheric sampling of Supertyphoon Mireille with NASA DC-8 aircraft on September 27, 1991, during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC; NITROGEN AB The DC-8 mission of September 27, 1991, was designed to sample air flowing into Typhoon Mireille in the boundary layer, air in the upper tropospheric eye region, and air emerging from the typhoon and ahead of the system, also in the upper troposphere. The objective was to find how a typhoon redistributes trace constituents in the West Pacific region and whether any such redistribution is important on the global scale. The boundary layer air (300 m), in a region to the SE of the eye, contained low mixing ratios of the tracer species O-3, CO, C2H6, C2H2, C3H8, C6H6 and CS2 but high values of dimethylsulfide (DMS). The eye region relative to the boundary layer, showed somewhat elevated levels of CO, substantially increased levels of O-3, CS2 and all nonmethane hydrocarbons (NMHCs), and somewhat reduced levels of DMS. Ahead of the eye, CO and the NMHCs remained unchanged, O-3 and CS2 showed a modest decrease, and DMS showed a substantial decrease. There was no evidence from lidar cross sections of ozone for the downward entrainment of stratospheric air into the eye region; these sections show that low ozone values were measured in the troposphere. The DMS data suggest substantial entrainment of boundary layer air into the system, particularly into the eye wall region. Estimates of the DMS sulphur flux between the boundary layer and the free troposphere, based on computations of velocity potential and divergent winds, gave values of about 69 mu g S m(-2) d(-1) averaged over a 17.5 degrees grid square encompassing the typhoon. A few hours after sampling with the DC-8, Mireille passed over Oki Island, just to the north of Japan, producing surface values of ozone of 5.5 ppbv. These O-3 levels are consistent with the low tropospheric values found by lidar and are more typical of equatorial regions. We suggest that the central eye region may act like a Taylor column which has moved poleward from low latitudes. The high-altitude photochemical environment within Typhoon Mireille was found to be quite active as evidenced by significant levels of measured gas phase H2O2 and CH3OOH and model-computed levels of OH. C1 UNIV TOKYO, MEGURO KU, TOKYO 153305, JAPAN. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23681 USA. DREXEL UNIV, PHILADELPHIA, PA 19104 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, AMES RES CTR, AMES SCI & APPLICAT AIRCRAFT DIV, MOFFETT FIELD, CA 94035 USA. SCI & TECHNOL CORP, HAMPTON, VA 23681 USA. UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. UNIV RHODE ISL, KINGSTON, RI 02881 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. NATL TAIWAN UNIV, DEPT ATMOSPHER SCI, TAIPEI 10764, TAIWAN. NATL INST ENVIRONM STUDIES, TSUKUBA, IBARAKI, JAPAN. NAGOYA UNIV, NAGOYA, AICHI, JAPAN. RP Newell, RE (reprint author), MIT, 54-1824, 77 MASSACHUSETTS AVE, CAMBRIDGE, MA 02139 USA. RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012; Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 23 TC 37 Z9 36 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1853 EP 1871 DI 10.1029/95JD01374 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600036 ER PT J AU Thornton, DC Bandy, AR Blomquist, BW Anderson, BE AF Thornton, DC Bandy, AR Blomquist, BW Anderson, BE TI Impact of anthropogenic and biogenic sources and sinks on carbonyl sulfide in the North Pacific troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GLOBAL SULFUR CYCLE; ATMOSPHERIC OCS; SURFACE WATERS; GASEOUS SULFUR; CS2; VEGETATION; COS; OCEAN; DISTRIBUTIONS; VARIABILITY AB During September-October 1991 over 500 determinations of carbonyl sulfide (OCS) were made in the troposphere over the North Pacific Ocean as part of the NASA Pacific Exploratory Mission-West A project. Three distinct regimes were found in the distribution of OCS in the Pacific troposphere during this period. Under conditions of remote Pacific marine air, OCS had a mean of 495 parts per trillion by volume (pptv) with a standard error of the mean of 0.6 pptv and a standard deviation of 8.8 pptv. Under conditions of air transported from Asia and the North American Arctic, both elevated and depleted levels of OCS were found. Decreases in DCS of 10-20% from the remote Pacific mean were highly correlated with decreased carbon dioxide levels. Increases of 10-20% of OCS were highly correlated with increased carbon disulfide and other chemical indicators of anthropogenic sources. The constancy of the OCS mean for the remote Pacific marine air masses can be used to better understand the budget for OCS and its impact as a source of stratospheric sulfur dioxide. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RP Thornton, DC (reprint author), DREXEL UNIV, DEPT CHEM, PHILADELPHIA, PA 19104 USA. NR 41 TC 39 Z9 39 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1873 EP 1881 DI 10.1029/95JD00617 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600037 ER PT J AU Heikes, BG Lee, M Bradshaw, J Sandholm, S Davis, DD Crawford, J Rodriguez, J Liu, S McKeen, S Thornton, D Bandy, A Gregory, G Talbot, R Blake, D AF Heikes, BG Lee, M Bradshaw, J Sandholm, S Davis, DD Crawford, J Rodriguez, J Liu, S McKeen, S Thornton, D Bandy, A Gregory, G Talbot, R Blake, D TI Hydrogen peroxide and methylhydroperoxide distributions related to ozone and odd hydrogen over the North Pacific in the fall of 1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; 3-DIMENSIONAL NUMERICAL-MODEL; TROPOSPHERIC OZONE; UNITED-STATES; CLOUD DYNAMICS; CHEMISTRY; MICROPHYSICS; ACID; SO2 AB Hydrogen peroxide and methylhydroperoxide were measured in the troposphere over the western North Pacific as part of the airborne portion of NASA's Global Tropospheric Experiment/Pacific Exploratory Mission-West A field mission. The flights circled the North Pacific, focusing on the western Pacific, and extended from 300 to 13,000 m altitude. The hydroperoxides were uniquely separated and quantified using a high-pressure liquid chromatography system in conjunction with a continuous enzyme fluorometric instrument. Results show a latitudinal gradient in both peroxides at all altitudes; for example, between 3 and 5 km, H2O2 median values decrease from 1700 to 500 parts per trillion by volume (pptv) in going from 0 degrees-15 degrees N to 45 degrees-60 degrees N, and the corresponding decrease in CH3OOH was 1100 to 200 pptv. Concentration maxima are observed in both species at altitudes of 2 to 3 km with H2O2 concentrations below 1 km lower by 30%, 10% for CH3OOH, and even lower, by a factor of 10, for both above 9 km. The H2O2 to CH3OOH ratio increased with altitude and latitude with ratios (1 in the tropical surface layer and >2 at midlatitude high altitude. Highest peroxide concentrations were encountered over the Celebes Sea in air which was impacted by aged biomass fire and urban pollutants. CH3OOH was below the level of detection in stratospheric air, H2O2 exceeded SO2 95% of the time, with the exceptions generally above 9 km. Above 3 km, O-3 increases with decreasing H2O2 and CH3OOH. Below 3 km the O-3-CH3OOH trend is the same but O-3 increases with increasing H2O2. The measurements are compared with predictions based upon a photochemical steady state zero-dimensional model and a three-dimensional mesoscale time-dependent model. These models capture observed trends in H2O2 and CH3OOH, with the possible exception of H2O2 below 2 km where surface removal is important. A surface removal lifetime of 3.5 days brings the observed and zero-dimensional model-estimated H2O2 into agreement. The steady state model suggests a strong correlation between the ratios of NO/CO or HO2/HO and the ratio of H2O2/CH3OOH. The observed hydroperoxide ratios bracket the modeled relationship with occasionally much lower H2O2 than expected. C1 DREXEL UNIV, PHILADELPHIA, PA 19104 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. NOAA, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80303 USA. AER INC, CAMBRIDGE, MA 02139 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. RP Heikes, BG (reprint author), UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER CHEM STUDIES, NARRAGANSETT, RI 02882 USA. RI McKeen, Stuart/H-9516-2013; Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 64 TC 61 Z9 61 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1891 EP 1905 DI 10.1029/95JD01364 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600039 ER PT J AU Singh, HB Gregory, GL Anderson, B Browell, E Sachse, GW Davis, DD Crawford, J Bradshaw, JD Talbot, R Blake, DR Thornton, D Newell, R Merrill, J AF Singh, HB Gregory, GL Anderson, B Browell, E Sachse, GW Davis, DD Crawford, J Bradshaw, JD Talbot, R Blake, DR Thornton, D Newell, R Merrill, J TI Low ozone in the marine boundary payer of the tropical Pacific Ocean: Photochemical loss, chlorine atoms, and entrainment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EQUATORIAL PACIFIC; TROPOSPHERE; LAYER; TEMPERATURE; PROFILES; CL AB Aircraft measurements of ozone, its key precursors, and a variety of chemical tracers were made in the troposphere of the western and central Pacific in October 1991. These data are presented and analyzed to examine the occurrence of low ozone concentrations in the remote marine boundary layer of the tropical and equatorial Pacific Ocean. The data from these flights out of Guam, covering an area extending from the equator to 20 degrees N and from south of the Philippines to Hawaii, show average O-3 concentrations as low as 8-9 ppb (ppb = 10(-9) v/v) at altitudes of 0.3-0.5 km in the boundary layer. Individual measurements as low as 2-5 ppb were recorded. Low O-3 concentrations do not always persist in space and time. High O-3, generally associated with the transport of upper tropospheric air, was also encountered in the boundary layer. In practically all cases, O-3 increased to values as large as 25-30 ppb within 2 km above the boundary layer top. Steady state model computations are used to suggest that these low O-3 concentrations are a result of net photochemical O-3 destruction in a low NO environment, sea surface deposition, and low net entrainment rates (3.6 +/- 1.7 mm s(-1)) from the free troposphere. Day/night measurements of select organic species (e.g., ethane, propane, C2Cl4) suggest that Cl atom concentrations in the vicinity of 10(5) molecules cm(-3) may be present in the marine boundary layer in the early morning hours. This Cl atom abundance can only be rationalized if sea-salt aerosols release active chlorine (Cl-2 or HOCl) to the gas phase when exposed to sunlight. These Cl atom concentrations, however, are still insufficient, and halogen chemistry is not likely to be an important contributor to the observed low O-3. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. UNIV RHODE ISL, NARRAGANSETT, RI 02882 USA. MIT, CAMBRIDGE, MA 02139 USA. UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. DREXEL UNIV, PHILADELPHIA, PA 19104 USA. RP Singh, HB (reprint author), NASA, AMES RES CTR, STOP 245-5, MOFFETT FIELD, CA 94035 USA. RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 34 TC 127 Z9 127 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1907 EP 1917 DI 10.1029/95JD01028 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600040 ER PT J AU Gregory, GL Anderson, BE Browell, EV AF Gregory, GL Anderson, BE Browell, EV TI Influence of lower tropospheric ozone on total column ozone as observed over the Pacific Ocean during the 1991 PEM-West A expedition SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AIRBORNE AB Pacific Exploratory Mission (PEM-West A) aircraft ozone data and concurrently measured TOMS atmospheric total column ozone data are examined, The focus of the paper is to determine, for relatively remote Pacific regions (110 degrees-180 degrees E longitude, 0 degrees-40 degrees N latitude), what fraction of total column ozone can be attributed to lower-tropospheric ozone (surface to 9-km altitude) and how this fraction varies with time At approximate to 30 degrees to 40 degrees N the surface to 9-km ozone column contributes about 14% to total column ozone. Of this 10%, about half is attributed to the surface to 3-km column. Nearer the equator (0 degrees-15 degrees N), the contributions are less, about 5 (0-9 km) and 1% (0-3 km) of the total column, respectively. Variations in ozone within the 3-km and 9-km columns over periods of days tend to be larger at northern latitudes. At 40 degrees to 50 degrees N, ozone variations within the columns can result in changes in each column's contribution to the total column that approach >50% of the column's contribution to the total column. Nearer the equator, variations are less than or equal to 1 Dobson unit which is generally <10% of the surface to 9-km column's contribution to total column ozone. The results provide insight into the relative importance of lower-tropospheric ozone to observed variations in atmospheric total column ozone and thus are important to the interpretation of total column measurements, especially for tropospheric studies. RP Gregory, GL (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL CODE 482, HAMPTON, VA 23681 USA. NR 19 TC 8 Z9 8 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1919 EP 1930 DI 10.1029/94JD02945 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600041 ER PT J AU Newell, RE Zhu, Y Browell, EV Ismail, S Read, WG Waters, JW Kelly, KK Liu, SC AF Newell, RE Zhu, Y Browell, EV Ismail, S Read, WG Waters, JW Kelly, KK Liu, SC TI Upper tropospheric water vapor and cirrus: Comparison of DC-8 observations, preliminary UARS microwave limb sounder measurements and meteorological analyses SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Upper tropospheric water vapor in the tropical West Pacific has been examined by three approaches that were operational during the NASA Pacific Exploratory Mission-West A (PEM-West A) in September-October 1991: direct measurement with a Lyman-a fluorescence instrument on the NASA DC-8; remote sensing by the microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS); and deduction of cirrus clouds by differential absorption lidar (DIAL) flown on the DC-8 together with environmental conditions derived from meteorological analyses made by the European Centre for Medium-Range Weather Forecasts (ECMWF). Comparison between the DC-8 direct measurement and the preliminary MLS (12 cases) estimates showed fair agreement with a tendency for MLS to show an overestimate at low mixing ratio values (less than or equal to similar to 200 parts per million by volume). The comparison between the DIAL and the ECMWF analyses (13 cases) showed that cirrus occurred in regions where there was rising motion and relative humidity near 100%. The DIAL observations are from much smaller spatial regions than can be resolved from the ECMWF analyses. The cirrus tops occurred below the tropopause as measured by the vertical ozone gradient in the DIAL data; no cases of tropopause penetration were observed during this season. In most cases the cirrus formed in air of low potential vorticity and relatively low ozone. At 150 and 200 hPa the center of the rising motion, as shown by the maximum in the velocity potential pattern based on the ECMWF analysis, is at about 18 degrees N, 145 degrees E in dose correspondence to the MLS water vapor mixing ratio maximum deduced for 147 and 215 hPa. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Newell, RE (reprint author), MIT, DEPT EARTH & ATMOSPHER SCI, 77 MASSACHUSETTS AVE, ROOM 54-1824, CAMBRIDGE, MA 02139 USA. NR 15 TC 23 Z9 23 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1931 EP 1941 DI 10.1029/95JD01373 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600042 ER PT J AU Newell, RE Wu, ZX Zhu, Y Hu, W Browell, EV Gregory, GL Sachse, GW Collins, JE Kelly, KK Liu, SC AF Newell, RE Wu, ZX Zhu, Y Hu, W Browell, EV Gregory, GL Sachse, GW Collins, JE Kelly, KK Liu, SC TI Vertical fine-scale atmospheric structure measured from NASA DC-8 during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Measurements of a suite of atmospheric trace constituents made from the NASA DC-8 aircraft, while it was making vertical profiles during the Pacific Exploratory Mission A (PEM-West A) to the western Pacific in September-October 1991 have revealed a layered structure in much of the region. Ozone, water vapor, carbon monoxide, and methane were available continuously and are the primary constituents used to define the layers; nonmethane hydrocarbons, carbon dioxide, hydrogen peroxide and methylhydroperoxide were available less frequently but were also used. From 105 vertical profiles, sampled at vertical speeds of about 6 m s(-1), over 500 layers were identified using O-3 and H2O; their mean thickness was about 400 m. When these layers could be identified from lidar along-track cross sections of O-3 made from the aircraft, they were found to extend over distances of 100-200 km or more. Combinations of several constituent deviations from vertical running means were used to identify possible layer sources; examples are high O-3, low H2O, CO, and CH4, corresponding to the extrusion of stratospheric air into the troposphere; low O-3 and high H2O, originating from convection from the tropical boundary layer; high O-3, CO and CH4, low H2O, coming from convection from the continental boundary layer and transport in the upper troposphere, sometimes from distant sources. The layers show no clear relationship with wind velocity profiles measured simultaneously on the aircraft; there is some relationship with temperature and potential temperature, with some layers which show a stratospheric signature lying on isentropes that are in the lower stratosphere at higher latitudes. Potential vorticity (PV) is used as an additional tracer to check the conclusions about the different types of layers. While PV is often used as an indicator of stratospheric air, its use as an indicator of convection is also illustrated here. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. SCI & TECHNOL CORP, HAMPTON, VA 23681 USA. NOAA, BOULDER, CO 80303 USA. RP Newell, RE (reprint author), MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, 77 MASSACUSETTS AVE, ROOM 54-1824, CAMBRIDGE, MA 02139 USA. NR 21 TC 58 Z9 58 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1943 EP 1960 DI 10.1029/95JD02613 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600043 ER PT J AU Newell, RE Zhu, Y Browell, EV Read, WG Waters, JW AF Newell, RE Zhu, Y Browell, EV Read, WG Waters, JW TI Walker circulation and tropical upper tropospheric water vapor SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Maps of the boundary layer divergent wind component derived from velocity potential for two 35-day periods in 1991 and 1994 exhibit a pattern of convergence in the lower levels in the tropical western Pacific, following the Sun between hemispheres, and divergence in the eastern Pacific, these two features agreeing with schematics of the Walker circulation. Vertical motion maps show rising motion in the western Pacific and sinking motion in the eastern Pacific; water vapor maps derived from the microwave limb sounder on the Upper Atmosphere Research Satellite show a similar picture with moist plumes evident at 215 hPa in rising regions and dryness in sinking regions. While these three indicators of vertical motion are internally consistent and fit with accepted views of the Walker circulation, it is shown that there is not equally clear evidence that the eastern and western regions are directly linked by horizontal motions, particularly in the upper troposphere. Mass flux studies based on the divergent winds show that the southeastern Pacific anticyclonic region is fed by upper tropospheric inflow from all sides; in October 1991 the inflow from the west, east, south, and north contributed almost equally, while in February 1994 the inflow from the west was the largest contribution, but flow across the eastern and southern boundaries was also important. The water vapor maps suggest that a substantial fraction of air in the upper troposphere to the west of South America originates over the continent. Lidar measurements of cirrus show good evidence of diverging flow into the northern hemisphere from the rising motion in the west Pacific near 10 degrees S during February 1994. The situation in the southeastern Pacific cell in October 1991 is somewhat analogous to that in the northwestern Pacific cell in February 1994 in that flow from a nearby landmass is entrained into the circulation. From daily water vapor maps coupled with potential vorticity maps and cross sections, it is suggested that direct exchange between the stratosphere and the troposphere in the form of almost vertical plumes may occur in subsiding regions in the tropics. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RP Newell, RE (reprint author), MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, 77 MASSACHUSETTS AVE, ROOM 54-1824, CAMBRIDGE, MA 02139 USA. NR 15 TC 42 Z9 42 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1961 EP 1974 DI 10.1029/95JD02275 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600044 ER PT J AU Collins, JE Sachse, GW Anderson, BE Harriss, RC Bartlett, KB Sandholm, S Wade, LO Burney, LG Hill, GF AF Collins, JE Sachse, GW Anderson, BE Harriss, RC Bartlett, KB Sandholm, S Wade, LO Burney, LG Hill, GF TI Airborne nitrous oxide observations over the western Pacific Ocean: September October 1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RICE FIELDS; EMISSIONS; SINKS; N2O; TRENDS AB The Langley tunable diode laser instrument package incorporated an additional channel to measure nitrous oxide (N2O) during the Pacific Exploratory Mission (PEM) West A. These measurements represent the first airborne, fast response (5-s) N2O data set obtained within the troposphere, Most data were recorded over the western Pacific between 0 degrees N and 45 degrees N latitude, 110 degrees E and 180 degrees E longitude, and 0.3 to 12 km altitude. Important observations include a decreasing N2O latitude gradient of approximately 0.4 parts per billion volumn (ppbv) from northern midlatitudes to the equator, a decreasing N2O longitude gradient of 0.4 ppbv from the western Pacific to the central Pacific at northern midlatitudes, and an enhancement of 0.2 ppbv in the boundary layer (altitudes below 0.5 km) relative to the rest of the tropospheric vertical profile. Other observations include increased N2O mixing ratios within both urban and biogenic affected air masses and reduced N2O mixing ratios in stratospheric intrusions. These relationships with air mass source characteristics are exhibited in the large-scale correlations between N2O and CO, CH4, and CO2 in the free troposphere. Atmospheric inputs of N2O are examined and the relative strengths of continental biogenic and anthropogenic/industrial sources are estimated. The data set is also examined for evidence of an oceanic source of N2O. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. NASA, LANGLEY RES CTR, DIV AEROSP ELECTR SYST, HAMPTON, VA 23681 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23666 USA. RP Collins, JE (reprint author), SCI & TECHNOL CORP, 101 RES DR, HAMPTON, VA 23666 USA. NR 34 TC 12 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1975 EP 1984 DI 10.1029/95JD02530 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600045 ER PT J AU Anderson, BE Gregory, GL Collins, JE Sachse, GW Conway, TJ Whiting, GP AF Anderson, BE Gregory, GL Collins, JE Sachse, GW Conway, TJ Whiting, GP TI Airborne observations of spatial and temporal variability of tropospheric carbon dioxide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CO2; GLOBAL DISTRIBUTION; CLIMATE; MODEL AB Fast response (5-s resolution) CO2 measurements were recorded on two recent NASA-sponsored airborne atmospheric chemical survey missions: the summer/fall 1991 Pacific Exploratory Mission-West A (PEM-West A) and the winter 1992 Airborne Arctic Stratospheric Expedition II (AASE II). Both missions were conducted aboard the NASA Ames Research Center DC-8 aircraft and included sampling between the surface and 12-km altitudes over a wide range of latitudes and longitudes. In the following text, these data, along with simultaneous surface measurements from the NOAA flask sampling network, are examined to establish the vertical distribution and variability of CO2 as a function of location and season. Results indicate that middle to upper tropospheric (> 5 km altitude) CO2 concentrations often differ considerably (> 5 parts per million by volume in some cases) from values recorded at surface stations within the same geographic region. These differences are particularly notable at middle to high northern latitudes where midtropospheric concentration changes and seasonal cycles are generally delayed in time and highly damped in amplitude relative to surface observations. C1 SCI & TECHNOL CORP, HAMPTON, VA 23666 USA. NOAA, AIR RESOURCES LAB, GMCC, BOULDER, CO 80303 USA. NASA, LANGLEY RES CTR, AEROSP ELECTR SYST DIV, HAMPTON, VA 23681 USA. CHRISTOPHER NEWPORT UNIV, DEPT ENVIRONM SCI, NEWPORT NEWS, VA 23668 USA. RP Anderson, BE (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. NR 45 TC 43 Z9 43 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 1985 EP 1997 DI 10.1029/95JD00413 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600046 ER PT J AU Crawford, J Davis, D Chen, G Bradshaw, J Sandholm, S Gregory, G Sachse, G Anderson, B Collins, J Blake, D Singh, H Heikes, B Talbot, R Rodriguez, J AF Crawford, J Davis, D Chen, G Bradshaw, J Sandholm, S Gregory, G Sachse, G Anderson, B Collins, J Blake, D Singh, H Heikes, B Talbot, R Rodriguez, J TI Photostationary state analysis of the NO2-NO system based on airborne observations from the western and central North Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PHOTOCHEMISTRY EXPERIMENT; TROPOSPHERIC OZONE; RADIOMETER MEASUREMENTS; PEROXY-RADICALS; EASTERN PACIFIC; UNITED-STATES; AIR; IODINE; MODEL; HYDROCARBONS AB On the basis of measurements taken during the NASA Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-West A (PEM-West A), photostationary state model calculations were carried out for approximately 1300 three-minute sample runs. The objective of his study was to look at a subset of this processed data to assess the level of agreement between observed ratios of NO2 to NO and those estimated using current photochemical theory. This filtered data subset consisted of 562 NO2-NO data pairs. The comparison between observations and predictions was based on the use of the photochemical test ratio (NO2)(expt)/(NO2)(calc), designated here as R(e)/R(c). Although the expected median value for this test ratio was unity, for the PEM-West A data set it was found to be 3.36. The value of the ratio R(e)/R(c) showed a general trend of increasing magnitude with increasing altitude and decreasing latitude. Attempts to understand the sizable discrepancy between observation and prediction (especially for the high-altitude and low-latitude data) were explored in the context of two hypotheses: (1) incomplete model chemistry and (2) interferences in the measurement of NO2. Efforts to quantify the levels of HO2, CH3O2, RO(2), and/or ClOx needed to correct the R(e)/R(c) discrepancy led to major inconsistencies in the predicted levels of other chemical species. Bromine and iodine chemistries were also investigated with results requiring Br-x and I-x radical levels well in excess of what would seem reasonable given our current understanding of the Source strengths for these elements. This suggests that incompleteness in the model's chemistry was unlikely the major cause of the discrepancy. The second hypothesis, involving interference in the measurement of NO2, now appears to be the most likely explanation for the largest component of the deviation in R(e)/R(c) from unity. For example, the disagreement between (NO2)(expt) and (NO2)(calc) was found to be a strong function of the NOx/NOy ratio. Also, the magnitude of the discrepancy between (NO2)(expt) and (NO2)(calc) fell within the possible limits defined by other reactive nitrogen species (e.g., Delta NOy) available to generate the interference. These results suggest that the further development of a new direct measurement technique for NO2, involving a wall collision-free inlet system, should be considered a high priority. We should also continue, however, to examine the chemical basis of current photochemical models to assess whether yet untested mechanisms might not provide an explanation for these observations. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. SCI & TECHNOL CORP, HAMPTON, VA 23681 USA. UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92717 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV RHODE ISL, GRAD SCH OCEANOG, NARRAGANSETT, RI 02882 USA. AER INC, CAMBRIDGE, MA 02139 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. RP Crawford, J (reprint author), GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 64 TC 78 Z9 78 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 2053 EP 2072 DI 10.1029/95JD02201 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600052 ER PT J AU Liu, SC McKeen, SA Hsie, EY Lin, X Kelly, KK Bradshaw, JD Sandholm, ST Browell, EV Gregory, GL Sachse, GW Bandy, AR Thornton, DC Blake, DR Rowland, FS Newell, R Heikes, BG Singh, H Talbot, RW AF Liu, SC McKeen, SA Hsie, EY Lin, X Kelly, KK Bradshaw, JD Sandholm, ST Browell, EV Gregory, GL Sachse, GW Bandy, AR Thornton, DC Blake, DR Rowland, FS Newell, R Heikes, BG Singh, H Talbot, RW TI Model study of tropospheric trace species distributions during PEM-West A SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UNITED-STATES; ODD NITROGEN; EMISSIONS; OZONE; INVENTORY; SIMULATION; NOX AB A three-dimensional mesoscale transport/photochemical model is used to study the transport and photochemical transformation of trace species over eastern Asia and western Pacific for the period from September 20 to October 6, 1991, bf the Pacific Exploratory Mission-West A experiment. The influence of emissions from the continental boundary layer that was evident in the observed trace species distributions in the lower troposphere over the ocean is well simulated by the model, In the upper troposphere, species such as O-3, NOy (total reactive nitrogen species), and SO2 which have a significant source in the stratosphere are also simulated well in the model, suggesting that the upper tropospheric abundances of these species are strongly influenced by stratospheric fluxes and upper tropospheric sources. In the case of SO2 the stratospheric flux is identified to be mostly from the Mount Pinatubo eruption, Concentrations in the upper troposphere for species such as CO and hydrocarbons,which are emitted in the continental boundary layer and have a sink in the troposphere, are significantly underestimated by the model, Two factors have been identified to contribute significantly to the underestimate: one is emissions upwind of the model domain (eastern Asia and western Pacific); the other is that vertical transport is underestimated in the model, Model results are also grouped by back trajectories to study the contrast between compositions of marine and continental air masses, The model-calculated altitude profiles of trace species in continental and marine air masses are found to be qualitatively consistent with observations, However, the difference in the median values of trace species between continental air and marine air is about twice as large for the observed values as for model results, This suggests that the model underestimates the outflow fluxes of trace species from the Asian continent and the Pacific rim countries to the ocean, Observed altitude profiles for species like CO and hydrocarbons show a negative gradient in continental air and a positive gradient in marine air, A mechanism which may be responsible for the altitude gradients is proposed. C1 DREXEL UNIV, PHILADELPHIA, PA 19104 USA. UNIV CALIF IRVINE, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV RHODE ISL, NARRAGANSETT, RI 02882 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. MIT, CAMBRIDGE, MA 02139 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV NEW HAMPSHIRE, DURHAM, NH 03824 USA. RP Liu, SC (reprint author), NOAA, AERON LAB, BOULDER, CO 80303 USA. RI McKeen, Stuart/H-9516-2013; Hsie, Eirh-Yu/I-4449-2013 OI Hsie, Eirh-Yu/0000-0003-3934-9923 NR 45 TC 49 Z9 50 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 2073 EP 2085 DI 10.1029/95JD02277 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600053 ER PT J AU McKeen, SA Liu, SC Hsie, EY Lin, X Bradshaw, JD Smyth, S Gregory, GL Blake, DR AF McKeen, SA Liu, SC Hsie, EY Lin, X Bradshaw, JD Smyth, S Gregory, GL Blake, DR TI Hydrocarbon ratios during PEM-WEST A: A model perspective SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC AIR MASSES; ATMOSPHERIC CONCENTRATIONS; PHOTOCHEMICAL HISTORIES; TROPOSPHERIC CHEMISTRY; RADICAL CONCENTRATIONS; RURAL TROPOSPHERE; POINT-ARENA; NOX; CALIFORNIA; EMISSIONS AB A useful application of the hydrocarbon measurements collected during the Pacific Exploratory Mission (PEM-West A) is as markers or indices of atmospheric processing. Traditionally, ratios of particular hydrocarbons have been interpreted as photochemical indices, since much of the effect due to atmospheric transport is assumed to cancel by using ratios. However, an ever increasing body of observatonial and theoretical evidence suggests that turbulent mixing associated with atmospheric transport influences certain hydrocarbon ratios significantly. In this study a three-dimensional mesoscale photochemical model is used to study the interaction of photochemistry and atmospheric mixing on select hydrocarbons. In terms of correlations and functional relationships between various alkanes the model results and PEM-West A hydrocarbon observations share many similar characteristics as well as explainable differences. When the three-dimensional model is applied to inert tracers, hydrocarbon ratios and other relationships exactly follow those expected by simple dilution with model-imposed ''background air,'' and the three-dimensional results for reactive hydrocarbons are quite consistent with a combined influence of photochemistry and simple dilution. Analogous to these model results, relationships between various hydrocarbons collected during the PEM-West A experiment appear to be consistent with this simplified picture of photochemistry and dilution affecting individual air masses, When hydrocarbons are chosen that have negligeble contributions to clean background air, unambiguous determinations of the relative contributions to photochemistry and dilution can be estimated from the hydrocarbon samples, Both the three-dimensional model results and the observations imply an average characteristic lifetime for dilution with background air roughly equivalent to the photochemical lifetime of butane for the western Pacific lower troposphere. Moreover, the dominance of OR as the primary photochemical oxidant downwind of anthropogenic source regions can be inferred from correlations between the highly reactive alkane ratios, By incorporating back-trajectory information within the three-dimensional model analysis, a correspondence between time and a particular hydrocarbon or hydrocarbon ratio can be determined, and the influence of atmospheric mixing or photochemistry can be quantified, Results of the three-dimensional model study are compared and applied to the PEM-West A hydrocarbon dataset, yielding a practical methodology for determining average OH concentrations and atmospheric mixing rates from the hydrocarbon measurements. Aircraft data taken below 2 km during wall flights east of Japan imply a diurnal average OH concentration of similar to 3 x 10(6) cm(-3). The characteristic time for dilution with background air is estimated to be similar to 2.5 days for the two study areas examined in this work. C1 UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92717 USA. GEORGIA INST TECHNOL, ATLANTA, GA 30332 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. RP McKeen, SA (reprint author), NOAA, AERON LAB, 325 BROADWAY, R-E-AL4, BOULDER, CO 80303 USA. RI McKeen, Stuart/H-9516-2013; Hsie, Eirh-Yu/I-4449-2013 OI Hsie, Eirh-Yu/0000-0003-3934-9923 NR 42 TC 101 Z9 102 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 2087 EP 2109 DI 10.1029/95JD02733 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600054 ER PT J AU Davis, DD Crawford, J Chen, G Chameides, W Liu, S Bradshaw, J Sandholm, S Sachse, G Gregory, G Anderson, B Barrick, J Bachmeier, A Collins, J Browell, E Blake, D Rowland, S Kondo, Y Singh, H Talbot, R Heikes, B Merrill, J Rodriguez, J Newell, RE AF Davis, DD Crawford, J Chen, G Chameides, W Liu, S Bradshaw, J Sandholm, S Sachse, G Gregory, G Anderson, B Barrick, J Bachmeier, A Collins, J Browell, E Blake, D Rowland, S Kondo, Y Singh, H Talbot, R Heikes, B Merrill, J Rodriguez, J Newell, RE TI Assessment of ozone photochemistry in the western North Pacific as inferred from PEM-West A observations during the fall 1991 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC OZONE; EQUATORIAL PACIFIC; LOWER STRATOSPHERE; BOUNDARY-LAYER; POLAR SUNRISE; VERTICAL FLUX; UNITED-STATES; NITRIC-OXIDE; CHEMISTRY; MODEL AB This study examines the influence of photochemical processes on ozone distributions in the western North Pacific. The analysis is based on data generated during NASA's western Pacific Exploratory Mission (PEM-West A) during the fall. of 1991. Ozone trends were best described in terms of two geographical domains: the western North Pacific rim (WNPR) and the western tropical North Pacific (WTNP). For both geographical regions, ozone photochemical destruction, D(O-3), decreased more rapidly with altitude than did photochemical formation, F(O-3). Thus the ozone tendency, P(O-3), was typically found to be negative for z < 6 km and positive for z > 6-8 km. For nearly all altitudes and latitudes, observed nonmethane hydrocarbon (NMHC) levels were shown to be of minor importance as ozone precursor species. Air parcel types producing the largest positive values of P(O-3) included fresh continental boundary layer (BL) air and high-altitude (z > 7 km) parcels influenced by deep convection/lightning. Significant negative P(O-3) values were found when encountering clean marine BL air or relatively clean lower free-tropospheric air. Photochemical destruction and formation fluxes for the Pacific rim region were found to exceed average values cited for marine dry deposition and stratospheric injection in the northern hemisphere by nearly a factor of 6. This region was also found to be in near balance with respect to column-integrated O-3 photochemical production and destruction. By contrast, for the tropical regime column-integrated O-3 showed photochemical destruction exceeding production by nearly 80%. Both transport of O-3 rich midlatitude air into the tropics as well as very high-altitude (10-17 km) photochemical. O-3 production were proposed as possible additional sources that might explain this estimated deficit. Results from this study further suggest that during the fall. time period, deep convection over Asia and Malaysia/Indonesia provided a significant source of high-altitude NOx to the western Pacific. Given that the high-altitude NOx lifetime is estimated at between 3 and 9 days, one would predict that this source added significantly to high altitude photochemical O-3 formation over large areas of the western Pacific. When viewed in terms of strong seasonal westerly flow, its influence would potentially span a large part of the Pacific. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. UNIV CALIF IRVINE, DEPT CHEM, IRVINE, CA 92717 USA. UNIV RHODE ISL, GRAD SCH OCEANOG, NARRAGANSETT, RI 02882 USA. NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA, AICHI 442, JAPAN. NOAA, AERON LAB, ENVIRONM RES LABS, BOULDER, CO 80303 USA. MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02139 USA. AER INC, CAMBRIDGE, MA 02139 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV NEW HAMPSHIRE, INST STUDY EARTH OCEANS & SPACE, DURHAM, NH 03824 USA. RP Davis, DD (reprint author), GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. RI Kondo, Yutaka/D-1459-2012; Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 63 TC 133 Z9 137 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1996 VL 101 IS D1 BP 2111 EP 2134 DI 10.1029/95JD02755 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TR616 UT WOS:A1996TR61600055 ER PT J AU Ahlheim, M Barzoukas, M Bedworth, PV BlanchardDesce, M Fort, A Hu, ZY Marder, SR Perry, JW Runser, C Staehelin, M Zysset, B AF Ahlheim, M Barzoukas, M Bedworth, PV BlanchardDesce, M Fort, A Hu, ZY Marder, SR Perry, JW Runser, C Staehelin, M Zysset, B TI Chromophores with strong heterocyclic acceptors: A poled polymer with a large electro-optic coefficient SO SCIENCE LA English DT Article ID CONJUGATED ORGANIC-MOLECULES AB Syntheses of a series of conjugated donor-acceptor chromophores, based on a strongly electron-withdrawing heterocyclic acceptor, have led to compounds with large second-order optical nonlinearities. Incorporation of one of these chromophores into polycarbonate at 20 percent weight loading yielded, after poling at 150 volts per micrometer, a polymer film with an electro-optic coefficient, r(33), of 55 picometers per volt at 1.313 micrometers. This value is roughly twice that of lithium niobate. A variant of one of these chromophores exhibited improved thermal stability as needed for use in polymers with higher glass transition temperatures. The chromophore was soluble in common organic solvents, had a scalar product of the dipole moment, mu, and the molecular first hyperpolarizability, beta (corrected for dispersion), of roughly 5000 x 10(-48) electrostatic units, and showed less than 10 percent decomposition after heating for 20 minutes in air and at 200 degrees C in an inert organic solvent. C1 CALTECH, BECKMAN INST, PASADENA, CA 91125 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. SANDOZ HUNINGUE SA, F-68330 HUNINGUE, FRANCE. INST PHYS & CHEM MAT STRASBOURG, UM 046 CNRS, F-67037 STRASBOURG, FRANCE. ECOLE NORMALE SUPER, DEPT CHIM, URA 1679 CNRS, F-75231 PARIS 05, FRANCE. UNIV BASEL, INST PHYS, CH-4056 BASEL, SWITZERLAND. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 17 TC 160 Z9 167 U1 4 U2 28 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 19 PY 1996 VL 271 IS 5247 BP 335 EP 337 DI 10.1126/science.271.5247.335 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TQ528 UT WOS:A1996TQ52800035 ER PT J AU Sutter, JK Jobe, JM Crane, EA AF Sutter, JK Jobe, JM Crane, EA TI Statistical design in isothermal aging of polyimide resins (vol 57, pg 1491, 1995) SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Correction, Addition C1 MIAMI UNIV,OXFORD,OH 45056. JOHN CARROLL UNIV,CLEVELAND,OH 44118. RP Sutter, JK (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 1 TC 0 Z9 0 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 JAN 18 PY 1996 VL 59 IS 3 BP 565 EP 565 PG 1 WC Polymer Science SC Polymer Science GA TK764 UT WOS:A1996TK76400024 ER PT J AU Duvall, TL DSilva, S Jefferies, SM Harvey, JW Schou, J AF Duvall, TL DSilva, S Jefferies, SM Harvey, JW Schou, J TI Downflows under sunspots detected by helioseismic tomography SO NATURE LA English DT Article ID SOLAR AB SUNSPOTS are areas of cooler gas and stronger magnetic fields in the Sun's photosphere (its 'surface'), but just how they form and are maintained has long been a puzzle. It has been proposed(1) that small vertical magnetic flux tubes, generated deep within the Sun, develop downflows around them when they emerge at the surface. The downflows bring together a large number of flux tubes in a cluster to form a sunspot, which behaves as a single flux bundle as long as the downflows bind the flux tubes together. Until now, however, it has not been possible to test this model with subsurface observations. Here we use the recently developed technique of travel time helioseismology(2) to detect the presence of strong downflows beneath both sunspots and the bright features known as plages. The flows have a velocity of similar to 2 km s(-1), and they persist to a depth of about 2,000 km. The data suggest, however, that the vertical magnetic field can be a coherent Bur bundle only to a depth of similar to 600 km; below this depth it is possible that the downflows hold together a loose collection of flux tubes to maintain the sunspots that we see. C1 NATL OPT ASTRON OBSERV,NATL SOLAR OBSERV,TUCSON,AZ 85726. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. STANFORD UNIV,HEPL,STANFORD,CA 94305. RP Duvall, TL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Duvall, Thomas/C-9998-2012 NR 9 TC 154 Z9 155 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 18 PY 1996 VL 379 IS 6562 BP 235 EP 237 DI 10.1038/379235a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TQ169 UT WOS:A1996TQ16900039 ER PT J AU Watson, BC Noor, AK AF Watson, BC Noor, AK TI Nonlinear structural analysis on distributed-memory computers SO COMPUTERS & STRUCTURES LA English DT Article ID SPARSE AB A computational strategy is presented for the nonlinear static and postbuckling analyses of large complex structures on massively parallel computers. The strategy is designed for distributed-memory, message-passing parallel computer systems. The key elements of the proposed strategy are: (a) a multiple-parameter reduced basis technique; (b) a nested dissection (or multilevel substructuring) ordering scheme: (c) parallel assembly of global matrices; and (d) a parallel sparse equation solver. The effectiveness of the strategy is assessed by applying it to thermo-mechanical postbuckling analyses of stiffened composite panels with cutouts, and nonlinear large-deflection analyses of HSCT models on Intel Paragon XP/S computers. The numerical studies presented demonstrate the advantages of nested dissection-based solvers over traditional skyline-based solvers on distributed memory mechines. RP Watson, BC (reprint author), UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681, USA. NR 22 TC 5 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD JAN 17 PY 1996 VL 58 IS 2 BP 233 EP 247 DI 10.1016/0045-7949(95)00137-6 PG 15 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA TA789 UT WOS:A1996TA78900001 ER PT J AU Patnaik, SN Hopkins, DA Coroneos, R AF Patnaik, SN Hopkins, DA Coroneos, R TI Structural optimization with approximate sensitivities SO COMPUTERS & STRUCTURES LA English DT Article AB Computational efficiency in structural optimization can be enhanced if the intensive computations associated with the calculation of the sensitivities, that is, gradients of the behavior constraints, are reduced. Approximation to gradients of the behavior constraints that can be generated with a small amount of numerical calculations is proposed. Structural optimization with these approximate sensitivities produced correct optimum solution. Approximate gradients performed well for different nonlinear programming methods, such as the sequence of unconstrained minimization technique, method of feasible directions, sequence of quadratic programming and sequence of linear programming. Structural optimization with approximate gradients can reduce by one third the CPU time that would otherwise be required to solve the problem with explicit closed-form gradients. The proposed gradient approximation shows potential to reduce intensive computation that has been associated with traditional structural optimization. C1 LEWIS RES CTR,CLEVELAND,OH. RP Patnaik, SN (reprint author), NASA,LEWIS RES CTR,MS 49-8,21000 BROOK PK RD,CLEVELAND,OH 44135, USA. NR 17 TC 13 Z9 13 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD JAN 17 PY 1996 VL 58 IS 2 BP 407 EP 418 DI 10.1016/0045-7949(95)00123-X PG 12 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA TA789 UT WOS:A1996TA78900016 ER PT J AU Andrews, L Chertihin, GV Ricca, A Bauschlicher, CW AF Andrews, L Chertihin, GV Ricca, A Bauschlicher, CW TI Reactions of laser-ablated iron atoms with oxygen molecules: Matrix infrared spectra and density functional calculations of OFeO, FeOO, and Fe(O-2) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GAUSSIAN-BASIS SETS; SOLID ARGON; HUMAN OXYHEMOGLOBIN; OXYMYOGLOBIN; TEMPERATURE; RESOLUTION; PRODUCTS AB Reactions of laser-ablated Fe atoms and O-2 molecules in argon condensing on a 10 K surface have produced sharp infrared absorptions at 1204.5, 945.6, and 797.1 cm(-1) that are identified as FeOO and OFeO, respectively, through the use of isotopic substitution and DFT structure and isotopic frequency calculations. Annealing to 30 and 50 K produced a strong 956.0-cm(-1) band, which is due to cyclic Fe(O-2); visible photolysis destroyed the 1204.5 cm(-1) FeOO band, but it was regenerated on annealing. Formation of the more stable dioxo insertion product OFeO requires activation energy whereas the superoxo and peroxo addition products FeOO and Fe(O-2) can be formed on diffusion of cold reagents in solid argon. The FeOO spectrum observed and calculated here compares favorably with those reported for oxyhemoproteins, which provides further support for the Fe-O-O binding geometry in these biologically important metalloproteins. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Andrews, L (reprint author), UNIV VIRGINIA,DEPT CHEM,MCCORMICK RD,CHARLOTTESVILLE,VA 22901, USA. NR 41 TC 80 Z9 80 U1 1 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JAN 17 PY 1996 VL 118 IS 2 BP 467 EP 470 DI 10.1021/ja953338f PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA TQ269 UT WOS:A1996TQ26900023 ER PT J AU George, T Jacobsohn, E Pike, WT ChangChien, P Khan, MA Yang, JW Mahajan, S AF George, T Jacobsohn, E Pike, WT ChangChien, P Khan, MA Yang, JW Mahajan, S TI Novel symmetry in the growth of gallium nitride on magnesium aluminate substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID GAN AB The growth of GaN by metalorganic chemical vapor deposition on (111) and (100) magnesium aluminate (MgAl2O4) substrates is examined using transmission electron microscopy. The results indicate that mainly wurtzite GaN is grown for both orientations. On the (111) substrate the following epitaxial relationship is observed: (0001)GaN parallel to (111)MgAl2O4, and [11 (2) over bar 0]GaN parallel to [1 (1) over bar 0]MgAl2O4. During the early stages of the (100) growth, four orientations of the wurtzite phase and a zinc-blende phase are formed. With increasing thickness, one of the wurtzite orientations dominates, with the epitaxial relationship being (1 (1) over bar 01)GaN parallel to (100)MgAl2O4 and the [11 (2) over bar 0]GaN nearly parallel to [011]MgAl2O4. This choice of growth orientation appears to be determined primarily by the nature of the interfacial bonding, with the basal plane of each of the four wurtzite GaN variants being nearly aligned along one of the four (111) planes intersecting the (100) surface of the MgAl2O4. (C) 1996 American Institute of Physics. C1 APA OPT INC,BLAINE,MN 55449. CARNEGIE MELLON UNIV,DEPT MAT SCI,PITTSBURGH,PA 15213. RP George, T (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 7 TC 18 Z9 18 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 JAN 15 PY 1996 VL 68 IS 3 BP 337 EP 339 DI 10.1063/1.116708 PG 3 WC Physics, Applied SC Physics GA TP438 UT WOS:A1996TP43800020 ER PT J AU Siskind, DE Russell, JM AF Siskind, DE Russell, JM TI Coupling between middle and upper atmospheric NO: Constraints from HALOE observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NUMERICAL-MODEL AB Observations of NO, NO2, and CH4 from the HALOE instrument on the UARS satellite are used to investigate the transport of thermospheric NO into the middle atmosphere. By comparing the variation of NO and NO2 with simultaneous measurements of a long lived stratospheric tracer like CH4, regions of enhanced odd nitrogen can be quantified. Our results indicate substantial enhancement of NO in the high latitude winter mesosphere extending from thermospheric altitudes down to about 55-60 km. We also see evidence of substantial equatorward mixing of mesospheric NO. Occasional enhancements of NOx are seen extending down into the upper stratosphere in winter; however, they do not appear to persist. Observations by HALOE at latitudes up to 75-80 degrees in early spring show no evidence for enhanced NOx. This suggests that the effect of thermospheric NO on high latitude upper stratospheric O-3 may be less than previously thought. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP Siskind, DE (reprint author), USN,RES LAB,EO HULBURT CTR SPACE RES,CODE 7641,WASHINGTON,DC 20375, USA. NR 11 TC 26 Z9 26 U1 0 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 JAN 15 PY 1996 VL 23 IS 2 BP 137 EP 140 DI 10.1029/95GL03782 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TQ467 UT WOS:A1996TQ46700007 ER PT J AU Dunn, PJ Robbins, JW Bosworth, JM Kolenkiewicz, R AF Dunn, PJ Robbins, JW Bosworth, JM Kolenkiewicz, R TI Crustal deformation around the Gulf of California SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PLATE MOTION AB A number of Satellite Laser Ranging (SLR) sites in the southwest United States and Mexico, in operation for over ten years; have been supporting the global laser network measuring tectonic plate motion and providing information for studies of regional crustal deformation. Observations of the Laser Geodetic Satellite (LAGEOS) collected in 1994 by the transportable satellite laser ranging system, TLRS-4, at two sites on the Baja peninsula now provide the means to extend the network of fixed stations at Monument Peak and Otay Mountain in southern California and Mazatlan on mainland Mexico. After the third SLR occupation of Ensenada, it's estimated site motion exhibits nearly the full plate rate predicted by the NNR-NUVEL1A model for a location on the Pacific plate. At the southern tip of the Baja, the motion of Cabo San Lucas has an azimuth that is more westerly than that expected from Pacific modeled motion. This discrepancy in azimuth, in conjunction with the slower SLR recovered velocity for Mazatlan, results in an apparent 6 mm/yr faster spreading rate across the mouth of the Gulf of California than that predicted by the NUVEL-1A model. The velocities of the Monument Peak and Otay Mountain sites show the expected long-term difference from Pacific plate motion, due to their proximity to the San Andreas Fault system. C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. RP Dunn, PJ (reprint author), HUGHES STX CORP,7701 GREENBELT RD,GREENBELT,MD 20770, USA. NR 13 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 JAN 15 PY 1996 VL 23 IS 2 BP 193 EP 196 DI 10.1029/96GL00010 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TQ467 UT WOS:A1996TQ46700021 ER PT J AU Spangler, LH Farris, B Filer, ED Barnes, NP AF Spangler, LH Farris, B Filer, ED Barnes, NP TI A computational study of host effects on Er3+ upconversion and self-quenching efficiency in ten garnets SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID 1.73 MU-M; UP-CONVERSION; SPECTROSCOPIC ANALYSIS; LASER; Y3SC2AL3O12; ND-3+ AB A quantum-mechanical model is used to predict the energy levels and transition rates of Er in a variety of garnets in order to optimize laser performance. The existence of near resonances among the various Er manifolds as well as the transition rates are used to estimate upconversion and self-quenching of Er in ten different garnets. Morrison's quantum-mechanical point charge program for calculating crystal-field effects on rare-earth ions was used to fit experimentally determined Er:YAG energy levels obtained from the literature. Radial factors from this fit were used, along with x-ray data, to calculate theoretical levels and transition rates for Er3+ in other garnets. The calculations suggest that the crystal-field effect on the upper four levels of the ground I-4(15/2) manifold can dramatically effect resonances and thus affect upconversion and cross-relaxation processes. Additionally, a method by which they indicate how a large population density can efficiently be built up in the S-4(3/2) manifold is proposed, a necessary condition for upconversion lasing from that manifold. Based on a simple summation of cross-relaxation resonances that can contribute, LuGG is predicted to enhance this upconversion process. (C) 1996 American Institute of Physics. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP Spangler, LH (reprint author), MONTANA STATE UNIV,DEPT CHEM & BIOCHEM,BOZEMAN,MT 59717, USA. OI Spangler, Lee/0000-0002-3870-6696 NR 17 TC 15 Z9 15 U1 2 U2 3 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 JAN 15 PY 1996 VL 79 IS 2 BP 573 EP 577 DI 10.1063/1.360798 PG 5 WC Physics, Applied SC Physics GA TQ775 UT WOS:A1996TQ77500003 ER PT J AU Reid, JS Kolawa, E Garland, CM Nicolet, MA Cardone, F Gupta, D Ruiz, RP AF Reid, JS Kolawa, E Garland, CM Nicolet, MA Cardone, F Gupta, D Ruiz, RP TI Amorphous (Mo, Ta, or W)-Si-N diffusion barriers for Al metallizations SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; INTERFACIAL REACTIONS; AL/SI METALLIZATIONS; PHASE-EQUILIBRIA; SI CONTACTS; ALUMINUM; SILICON; NITRIDE; SYSTEMS; ALLOYS AB M-Si-N and M-Si (M=Mo, Ta, or W) thin films, reactively sputtered from M(5)Si(3) and WSi2 targets, are examined as diffusion barriers for aluminum metallizations of silicon. Methods of analysis include electrical tests of shallow-junction diodes, He-4(++) backscattering spectrometry, x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and secondary-ion-mass spectrometry. At the proper compositions, the M-Si-N films prevent Al overlayers from electrically degrading shallow-junction diodes after 10 min anneals above the melting point of aluminum. Secondary-ion-mass spectrometry indicates virtually no diffusivity of Al into the M-Si-N films during a 700 degrees C/10 h treatment. The stability can be partially attributed to a self-sealing 3-nm-thick A1N layer that grows at the M-Si-N/AI interface, as seen by transmission electron microscopy. (C) 1996 American Institute of Physics. C1 CALTECH,PASADENA,CA 91125. IBM CORP,RES LABS,YORKTOWN HTS,NY 10598. CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 49 TC 69 Z9 69 U1 1 U2 6 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 JAN 15 PY 1996 VL 79 IS 2 BP 1109 EP 1115 DI 10.1063/1.360909 PG 7 WC Physics, Applied SC Physics GA TQ775 UT WOS:A1996TQ77500079 ER PT J AU Kazmin, AS Rienecker, MM AF Kazmin, AS Rienecker, MM TI Variability and frontogenesis in the large-scale oceanic frontal zones SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SUBTROPICAL CONVERGENCE ZONE; WESTERN PACIFIC; FLUX MEASUREMENTS; SST VARIABILITY; TEMPERATURE; SATELLITE; VELOCITY; SALINITY; FASINEX; FIELDS AB Sea surface temperature (SST) from weekly global advanced very high resolution radiometer data for the period of 1982-1992 and estimates of the surface forcing due to wind stress and net heat flux are used to investigate a global monthly climatology of large-scale oceanic frontal zones (OFZs), the variability of SST gradient in several frontal zones, and the meridional frontogenesis in the North Pacific. Subpolar frontal zones are identifiable in the SST gradient field throughout the whole year while subtropical frontal zones appear as seasonal phenomena in the northern hemisphere. The magnitude and position of subtropical fronts were found to vary synchronously in both hemispheres, with maximum intensity in November to March. During this period, subtropical fronts in the northern hemisphere become clearly identifiable, separate features, while in the southern hemisphere their southern boundaries tend to merge with the subpolar front. In the northern hemisphere the northward shift of the subtropical frontal zones during late boreal spring results in a merger of the subpolar and subtropical zones by August. In the southern hemisphere, subtropical fronts separate from the subpolar front during this period and become clearly distinguishable, though less intense. Singular spectrum analysis of the 11-year time series of SST gradient in several OFZs revealed a seasonal signal as well as interannual variations that, in the equatorial zone, are related to Fl Nino events. The amplitude of the annual cycle is comparable in the subtropical and subpolar North Pacific, but the subtropics leads the subpolar zone by about 4 months. Combined forcing due to wind stress and net surface heat flux was found to be sufficient to describe most of the observed frontogenesis variability in North Pacific midlatitudes on seasonal timescales, but not on shorter timescales. In the subtropical zone, the Ekman convergence alone was not sufficient to provide the observed frontogenesis/frontolysis on seasonal time scales. In fact, when the maximum frontogenesis associated with Ekman convergence occurs in late spring/early summer, this is counteracted by the frontolytic effect of Ekman pumping and the dominating frontolytic effect of surface heat forcing. In summer, Ekman convergence is more important in the subpolar area where it is enhanced by the smaller frontogenetic effect of both Ekman pumping and surface heat forcing. Surface forcing due to wind stress and heat flux considered in this study does not explain the high-amplitude intraseasonal frontogenesis variations, especially in the subpolar region. C1 NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,HYDROSPHER PROC LAB,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD. RP Kazmin, AS (reprint author), PP SHIRSHOV OCEANOL INST,23 KRASIKOVA ST,MOSCOW 117218,RUSSIA. RI Kazmin, Alexander/F-3074-2015 NR 31 TC 31 Z9 34 U1 1 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 JAN 15 PY 1996 VL 101 IS C1 BP 907 EP 921 DI 10.1029/95JC02992 PG 15 WC Oceanography SC Oceanography GA TQ792 UT WOS:A1996TQ79200004 ER PT J AU Rienecker, MM Atlas, R Schubert, SD Willett, CS AF Rienecker, MM Atlas, R Schubert, SD Willett, CS TI A comparison of surface wind products over the North Pacific Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID KUROSHIO EXTENSION; STRESS; VARIABILITY; SCALE AB This study compares four surface wind products which may be used to force ocean circulation models of the North Pacific: wind stress derived from the Atlas special sensor microwave imager (SSM/I) based surface wind analyses (July 1987-June 1990), the Goddard Earth Observing System (CEOS) wind assimilation product at 10 m (March 1985-February 1990) and, at the appropriate overlapping times, the European Centre for Medium-Range Weather Forecasts (ECMWF) wind analyses and the Comprehensive Ocean-Atmosphere Data Set (COADS). Overall, there is good agreement in spatial and temporal variations between COADS and the model-based analyses. The COADS product used in this study, based on monthly averaged winds, underestimates the monthly averaged stresses in the higher latitudes where the submonthly variance is high. In the tropics and subtropics where the variance is lower, the COADS stresses are closer to climatology than the weaker model-based winds. The largest differences between the model-based analyses occur during winter in the northernmost region of the North Pacific basin where the spatial and temporal variability is largest. The seasonal mean Atlas SSM/I stresses are stronger overall than the other model-based analyses, with differences reaching as high as 0.09 N m(-2) in the high latitudes during winter. The Atlas product is also consistently stronger in the curl. Of the four curl products, the Atlas SSM/I and GEOS are closest in pattern and intensity in the tropics in both summer and winter. These also have the closest wavenumber spectral distribution in the high latitudes during winter. Integrations of a nonlinear, baroclinic quasigeostrophic ocean model using three of the wind stress curl distributions show differences of 30-45% in the mean integrated volume transport in the Kuroshio Extension. The Atlas SSM/I wind stress curl seems to force a more realistic subtropical gyre (in terms of transport and eddy energy levels) and western boundary current structure. The GEOS curl seems to force a more realistic subpolar gyre circulation. Overall, the assimilation of the SSM/I wind speed data improves the comparison between the model-based analyses and ship-based observations and produces more a realistic ocean model circulation. C1 UNIV COLORADO, COLORADO CTR ASTRODYNAM RES, DEPT AEROSP ENGN, BOULDER, CO 80302 USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RP NASA, GODDARD SPACE FLIGHT CTR, HYDROSPHER PROC LAB, OCEANS & ICE BRANCH, CODE 971, GREENBELT, MD 20771 USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 34 TC 26 Z9 26 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JAN 15 PY 1996 VL 101 IS C1 BP 1011 EP 1023 DI 10.1029/95JC03015 PG 13 WC Oceanography SC Oceanography GA TQ792 UT WOS:A1996TQ79200009 ER PT J AU Eluszkiewicz, J Crisp, D Zurek, R Elson, L Fishbein, E Froidevaux, L Waters, J Grainger, RG Lambert, A Harwood, R Peckham, G AF Eluszkiewicz, J Crisp, D Zurek, R Elson, L Fishbein, E Froidevaux, L Waters, J Grainger, RG Lambert, A Harwood, R Peckham, G TI Residual circulation in the stratosphere and lower mesosphere as diagnosed from Microwave Limb Sounder data SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERE RESEARCH SATELLITE; MIDDLE ATMOSPHERE; DIABATIC CIRCULATION; ZONAL WIND; PLANETARY ATMOSPHERES; MARTIAN ATMOSPHERE; RADIATIVE-TRANSFER; VENUS MESOSPHERE; MEAN CIRCULATION; DOWNWARD CONTROL AB Results for the residual circulation in the stratosphere and lower mesosphere between September 1991 and August 1994 are reported. This circulation is diagnosed by applying an accurate radiative transfer code to temperature, ozone, and water vapor measurements acquired by the Microwave Limb Sounder (MLS) onboard the Upper Atmosphere Research Satellite (UARS), augmented by climatological distributions of methane, nitrous oxide, nitrogen dioxide, surface albedo, and cloud cover. The sensitivity of the computed heating rates to the presence of Mt. Pinatubo aerosols is explored by utilizing aerosol properties derived from the measurements obtained by the Improved Stratospheric and Mesospheric Sounder instrument, also onboard UARS. The computed vertical velocities exhibit a semiannual oscillation (SAG) around the tropical stratopause, with the region of downward velocities reaching maximum spatial extent in February and August. This behavior reflects the semiannual oscillation in temperature and ozone and mimics that seen in past studies of the October 1978-May 1979 period based on data from the Limb Infrared Monitor of the Stratosphere onboard the Nimbus 7 satellite. The SAO vertical velocities are stronger during the northern winter phase, as expected if planetary waves from the winter hemisphere are involved in driving the SAG. A possible quasi-biennial oscillation (QBO) signal extending from the middle into the upper stratosphere is also hinted at, with the equatorial vertical velocities in the region 10-1 hPa significantly smaller (or even negative) in 1993/94 than in 1992/93. Despite the short data record, the authors believe that this pattern reflects a QBO signal rather than a coincidental interannual variability, since the time-height section of vertical velocity at the equator resembles that of the zonal wind. Wintertime high-latitude descent rates are usually greater in the Northern Hemisphere, but they also exhibit significant variability there. In the three northern winters analyzed in this study, strong downward velocities are diagnosed in the lower stratosphere during stratospheric warmings and are associated with enhanced wave forcing (computed as the momentum residual) in the mid- and upper stratosphere. The implications of the computed circulation for the distribution of tracers are illustrated by the example of the ''double-peaked'' structure in the water vapor distribution measured by MLS. C1 CALTECH, DIV GEOL & PLANETARY SCI, PASADENA, CA 91125 USA. CALTECH, JET PROP LAB, DIV EARTH & SPACE SCI, PASADENA, CA 91109 USA. UNIV OXFORD, OXFORD, ENGLAND. UNIV EDINBURGH, DEPT METEOROL, EDINBURGH, MIDLOTHIAN, SCOTLAND. HERIOT WATT UNIV, DEPT PHYS, EDINBURGH, MIDLOTHIAN, SCOTLAND. RI Grainger, Roy/E-8823-2011 OI Grainger, Roy/0000-0003-0709-1315 NR 85 TC 80 Z9 80 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JAN 15 PY 1996 VL 53 IS 2 BP 217 EP 240 DI 10.1175/1520-0469(1996)053<0217:RCITSA>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TU445 UT WOS:A1996TU44500002 ER PT J AU Bishop, CH AF Bishop, CH TI Domain-independent attribution .1. Reconstructing the wind from estimates of vorticity and divergence using free space Green's functions SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SERIES EXPANSION; LIMITED AREA AB Free space Green's functions may be used to reconstruct the wind over a limited domain from vorticity, divergence, and the wind at the boundary of the domain. When standard finite-difference estimates of the vorticity/divergence field are used, the technique fails to accurately reconstruct the wind in regions where the vorticity or divergence change markedly between grid boxes. The standard finite-difference estimate of vorticity/divergence is accurate provided that the wind varies linearly with distance along the edges of grid boxes. An estimate of vorticity/divergence is derived that accounts for the fact that these requirements are not met when the vorticity/divergence field is locally heterogeneous. This improved estimate is named the G4 estimate. It is not derived from Taylor series. When the G4 estimate of vorticity/divergence is used to reconstruct the wind field, the magnitude of the reconstruction error is an order of magnitude smaller than the reconstruction error associated with the standard estimate of vorticity/divergence. C1 NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE PROC BRANCH,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NR 11 TC 10 Z9 11 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 JAN 15 PY 1996 VL 53 IS 2 BP 241 EP 252 DI 10.1175/1520-0469(1996)053<0241:DIAPIR>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TU445 UT WOS:A1996TU44500003 ER PT J AU Bishop, CH AF Bishop, CH TI Domain-independent attribution .2. Its value in the verification of dynamical theories of frontal waves and frontogenesis SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID HORIZONTAL DEFORMATION; BAROCLINIC WAVES; VORTICITY; STABILITY; BEHAVIOR; EQUATION AB Theories of frontogenesis and frontal waves describe development in terms of the interaction of a basic state or environmental flow with a frontal flow. The basic-state flow may comprise a large-scale confluent-diffluent deformation field and/or an alongfront temperature gradient. The frontal flow is seen as evolving as a result of its interaction with the environmental flow. Such theories make specific predictions about the effect of the basic-state flow on the frontal how. To test these predictions, counterparts of the basic-state Bows and frontal Bows used in theoretical models must be extracted from atmospheric data. Here the concept of attribution is used to identify such counterparts. In the present context, attribution refers to the process whereby a part of the wind field is attributed to a part of the vorticity or divergence field. It is mathematically equivalent to the process by which a part of a field of electric potential is associated with an element of total charge density in electrostatics. The counterpart of the frontal flow used in idealized models is identified as that part of the flow attributable to the vorticity and divergence anomalies within the frontal region. The counterpart of the basic-state Bow is identified as that part of the flow attributable to vorticity and divergence anomalies outside the frontal region. Applications of the partitioning method are illustrated by diagnosing the flow associated with a North Atlantic front. The way in which the partitioning method may be used to test some theories concerning the effect of large-scale deformation on frontal wave formation is described. The partitioning method's ability to distinguish frontogenesis due to environmental flow from that due to frontal flow is also discussed. The analyzed front is found to lie at an angle to the dilatation axis of the environmental flow. It is argued that this feature must be common to all nonrotating finite length fronts. C1 NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE PROC BRANCH,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NR 21 TC 13 Z9 14 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 JAN 15 PY 1996 VL 53 IS 2 BP 253 EP 262 DI 10.1175/1520-0469(1996)053<0253:DIAPII>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TU445 UT WOS:A1996TU44500004 ER PT J AU Feibelman, WA Hyung, S Aller, LH AF Feibelman, WA Hyung, S Aller, LH TI The spectrum of the planetary nebula IC 351 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM, abundances; planetary nebulae, general; planetary nebulae, individual, IC 351 ID ABUNDANCES; EXTINCTION; EVOLUTION AB International Ultraviolet Explorer (IUE) and optical region spectroscopic observations are presented for the moderately high-excitation planetary nebula IC 351. Most of the atoms are distributed over a narrow range of ionization. Thus [N II] and [S II] are weak; [Ne IV] is prominent, but [Ne V] is missing. It appears that the metal/hydrogen ratio is smaller than in the Sun. No Si lines are seen either in optical or UV regions. It is suggested that virtually all Si atoms are locked in grains. The ionization correction factor method fails utterly for N, for example. Hence IUE data are essential for chemical composition estimates. Until high spatial resolution images are available, construction of a new theoretical model does not seem warranted. C1 UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90095. RP Feibelman, WA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6841,GREENBELT,MD 20771, USA. NR 37 TC 24 Z9 24 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 JAN 15 PY 1996 VL 278 IS 2 BP 625 EP 634 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ730 UT WOS:A1996TQ73000028 ER PT J AU Wang, Y AF Wang, Y TI Simple analytical methods for computing the gravity-wave contribution to the cosmic background radiation anisotropy SO PHYSICAL REVIEW D LA English DT Article ID GENERALIZED INFLATIONARY COSMOLOGIES; GRAVITATIONAL-WAVES; PERTURBATIONS AB We present two simple analytical methods; for computing the gravity-wave contribution to the cosmic background radiation (CBR) anisotropy in inflationary models; one method uses a time-dependent transfer function, the other method uses an approximate gravity-wave mode function which is a simple combination of the lowest order spherical Bessel functions. We compare the CBR anisotropy tensor multipole spectrum computed using our methods with the previous result of the highly accurate numerical method, the ''Boltzmann'' method. Our time-dependent transfer function is more accurate than the time-independent transfer function found by Turner, White, and Lidsey; however, we find that the transfer function method is only good for l less than or similar to 120. Using our approximate gravity-wave mode function, we obtain much better accuracy; the tensor multipole spectrum we find differs by less than 2% for l less than or similar to 50, less than 10% for I less than or similar to 120, and less than 20% for l less than or similar to 300 from the ''Boltsmann'' result. Our approximate graviton mode function should be quite useful in studying tensor perturbations from inflationary models. RP Wang, Y (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. RI Wang, Yun/B-5724-2011 OI Wang, Yun/0000-0002-4749-2984 NR 16 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1996 VL 53 IS 2 BP 639 EP 644 DI 10.1103/PhysRevD.53.639 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TT958 UT WOS:A1996TT95800011 ER PT J AU Smith, DE Zuber, MT AF Smith, DE Zuber, MT TI The shape of Mars and the topographic signature of the hemispheric dichotomy SO SCIENCE LA English DT Article ID RADIO OCCULTATION MEASUREMENTS; MARTIAN TOPOGRAPHY; SURFACE PROPERTIES; GIANT IMPACT; ATMOSPHERE; GRAVITY; RADAR; MARINER-9; HARMONICS; PLANET AB Reanalysis of occultation data from the Mariner 9 and Viking Orbiter spacecraft to determine the shape of Mars indicated that the hemispheric dichotomy is not a fundamental feature of the shape of the planet. It is a consequence of an approximately 3-kilometer offset between Mars's center of mass and center of figure, and the boundary, along most of its length, consists of broad, gradual surface slopes over distances of thousands of kilometers. This result was supported by analysis of high spatial resolution Earth-based radar topographic profiles. Any successful model for the origin of the dichotomy must explain a planet with an ellipsoidal shape and a long wavelength gradual topographic transition between the northern and southern hemispheres. C1 MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. RP Smith, DE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771, USA. NR 53 TC 65 Z9 65 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JAN 12 PY 1996 VL 271 IS 5246 BP 184 EP 188 DI 10.1126/science.271.5246.184 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TP364 UT WOS:A1996TP36400035 ER PT J AU Francisco, JS Sander, SP AF Francisco, JS Sander, SP TI Structures, relative stabilities, and vibrational spectra of isomers of HClO3 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID MOLECULAR-ENERGIES; OZONE; CLO; RADICALS; KINETICS; HO2; THERMOCHEMISTRY; STRATOSPHERE; DESTRUCTION; MECHANISMS AB Ab initio molecular orbital calculations have been carried out to examine the relative stabilities and the spectroscopy of isomers of HClO3. The lowest energy structure is HOClO2, and its heat of formation at 0 K is calculated to be 4.2 kcal mol(-1) as determined from G2 theory. The next lowest energy isomer is a skewed-straight chain HOOOCl. It is 4.9 kcal mol(-1) above the lowest energy form. The two higher energy structures are HOOClO and the hypervalent HClO3. An examination of the vibrational and electronic spectra reveals spectral features that allow these species to be uniquely distinguished. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 34 TC 29 Z9 30 U1 0 U2 6 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 JAN 11 PY 1996 VL 100 IS 2 BP 573 EP 579 DI 10.1021/jp950950k PG 7 WC Chemistry, Physical SC Chemistry GA TP942 UT WOS:A1996TP94200025 ER PT J AU Ashby, MLN Hacking, PB Houck, JR Soifer, BT Weisstein, EW AF Ashby, MLN Hacking, PB Houck, JR Soifer, BT Weisstein, EW TI A massive z=0.088 supercluster and tests of starburst galaxy evolution at the north ecliptic pole SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, general; galaxies, distances and redshifts; galaxies, starburst; infrared, galaxies ID LARGE-SCALE STRUCTURE; DEEP IRAS SURVEY; NUMBER COUNTS; COSMOLOGICAL EVOLUTION; RADIO-SOURCES; LUMINOSITY; FIELD; MAG AB We present redshifts and luminosities for galaxies in a very deep IRAS field around the north ecliptic pole region (NEPR). The redshift data set consists of 76 sources drawn from co-added and point source filtered IRAS scans of the pole region with 60 mu m flux densities bounded between 210 and 50 mJy. This is, tberefore, the deepest flux-limited far-infrared sample yet assembled: it extends out to a median redshift of z = 0.080. The sample is strongly clustered in redshift space, with one very strong concentration at z = 0.088, and at least four weaker clusters. The observed portion of the z = 0.088 cluster has a surface density of galaxies more than three times as dense as the Great Wall. This is the deepest far-infrared selected sample yet to become available for tests of starburst galaxy evolution. We have compared the redshift distribution of a subsample to evolutionary models and find the data consistent with either mild (L proportional to [1 + z](1-2)) luminosity evolution, mild (rho proportional to [1 + z](1-2)) comoving density evolution, or no evolution. It is difficult, however, to distinguish between true evolution and the effects of large-scale structure in a sample of this size. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,DEPT PHYS,PASADENA,CA 91125. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP Ashby, MLN (reprint author), CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853, USA. NR 27 TC 28 Z9 28 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 JAN 10 PY 1996 VL 456 IS 2 BP 428 EP 436 DI 10.1086/176667 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100003 ER PT J AU Markevitch, M Mushotzky, R Inoue, H Yamashita, K Furuzawa, A Tawara, Y AF Markevitch, M Mushotzky, R Inoue, H Yamashita, K Furuzawa, A Tawara, Y TI Abell 2163: Temperature, mass, and hydrostatic equilibrium SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; distance scale; galaxies, clusters, individual (A2163); X-rays, galaxies ID X-RAY; COMA CLUSTER; GALAXIES; EVOLUTION; ELECTRONS; A2256; GAS AB Using ASCA data, we have measured the electron temperature in Abell 2163 out to 1.5 h(-1) Mpc (3/4 of the virial radius, or 10a(X) where a(X) is the X-ray core-radius) from the center, in three radial bins. The obtained temperatures are 12.2(-1.2)(+1.9) keV, 11.5(-2.9)(+2.7) keV, and 3.8(-0.9)(+1.11) keV in the 0-3a(X) (0-3'.5), 3-6a(X) and 6-13a(X) spherical shells, respectively. [Errors are 90% throughout the paper unless otherwise stated, and h = H-0(100 km s(-1) Mpc(-1))(-1).] Formally applying the hydrostatic equilibrium and spherical symmetry assumptions and using these data together with the Ginga spectral and the ROSA T imaging data, we were able to severely limit the possible binding mass distribution of the generic form rho = rho(0)(1 + r(2)/a(b)(2))-n/2. All the allowed binding mass profiles are steeper than the gas density profiles, and mass profiles with the same slope as gas are excluded at a greater than 99% confidence. The total mass inside 0.5 h(-1) Mpc is 4.3 +/- 0.5 x 10(14) h(-1) M., of which 0.074h(-3/2) is gas, while inside 1.5h(-1) Mpc, the mass is 1.07 +/- 0.13 x 10(15) h(-1) M.. The strongest constraint on the mass profile is the observed quick drop of the temperature at large radii, which can be reconciled only marginally with the ROSAT detection of gas at an even greater radius. We note that in the outer part of this cluster, which is likely to be a recent merger, the timescale for reaching electron-ion temperature equality via collisions is comparable to the merger timescale, so the measured electron temperature may give an underestimate of the gas pressure there. Otherwise, if our low value is indeed representative of the gas temperature in the outer shell, the cluster atmosphere should be convectionally unstable, and gas turbulence should exist. Bulk motions of the gas are also expected during the merger. Their existence would increase the total gas pressure above that indicated by the observed temperature. Thus, failure of the model in which dark matter and gas have the same distribution at the radii of interest, which is favored by hydrodynamic simulations, may be due to the neglect of these phenomena, which leads to an underestimate of the total density and an overestimate of the baryonic fraction at large radii. The mass estimate at the smaller radius, where there is no evidence of departing from equilibrium, is likely to be correct. Our measured electron temperatures, combined with the previously reported Sunyaev-Zeldovich decrement toward this cluster and the ROSAT gas density profile, under the assumption of spherical symmetry, are consistent with a Hubble constant between 42 and 110 km s(-1) Mpc(-1) (68% interval), where the uncertainty is dominated by that of the available SZ measurement. C1 IKI,MOSCOW 117810,RUSSIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NAGOYA UNIV,DEPT PHYS,NAGOYA,AICHI 46101,JAPAN. RP Markevitch, M (reprint author), INST SPACE & ASTRONAUT SCI,3-1-1 YOSHINODAI,SAGAMIHARA,KANAGAWA 229,JAPAN. NR 40 TC 89 Z9 89 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 JAN 10 PY 1996 VL 456 IS 2 BP 437 EP 444 DI 10.1086/176668 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100004 ER PT J AU Ramaty, R Kozlovsky, B Lingenfelter, RE AF Ramaty, R Kozlovsky, B Lingenfelter, RE TI Light isotopes, extinct radioisotopes, and gamma-ray lines from low-energy cosmic-ray interactions SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; cosmic rays; Galaxy, abundances; gamma rays, theory nuclear reactions, nucleosynthesis, abundances; solar system, formation supernovae, general ID EARLY SOLAR-SYSTEM; MASSIVE STARS; PARTICLE INTERACTIONS; LI; NUCLEOSYNTHESIS; ELEMENTS; MODELS; NUCLEI; RATES AB We have carried out detailed calculations of gamma-ray line, light isotope, and extinct radioactive isotope production by low-energy cosmic rays for a broad range of accelerated particle abundances and energy spectra. We first apply these calculations to the gamma-ray line emission observed from the Orion molecular cloud complex. These gamma rays have provided the most direct evidence for the presence of large fluxes of low-energy cosmic rays in the Galaxy. Next we show that the bulk of the Galactic boron, beryllium, and 6Li could have been produced over the age of the Galaxy by interactions of low-energy cosmic rays having typical particle energies around 30 MeV nucleon(-1). Such cosmic-ray interactions can account for the observed meteoritic B-11/B-10 which is higher than the isotopic ratio predicted by relativistic cosmic-ray interactions. Low-energy cosmic rays of similar energies could have also made a significant contribution to the production of Ca-41 in meteoritic calcium-aluminum inclusions (CAIs) formed in the early solar system, provided that the cosmic-ray irradiation and CAI formation periods were essentially cotemporal. However, the production of significant amounts of Al-26 by low-energy cosmic rays in the early solar system is unlikely because it would overproduce Be-9 and Li-6. C1 TEL AVIV UNIV, SCH PHYS & ASTRON, RAMAT AVIV, ISRAEL. UNIV CALIF SAN DIEGO, CTR ASTROPHYS & SPACE SCI, LA JOLLA, CA 92093 USA. RP Ramaty, R (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. NR 52 TC 126 Z9 126 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1996 VL 456 IS 2 BP 525 EP 540 DI 10.1086/176677 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100013 ER PT J AU Telesco, CM Davidson, JA Werner, MW AF Telesco, CM Davidson, JA Werner, MW TI 10-30 micron maps of the central 5 parsecs of the galaxy: Heating of the cavity and neutral gas disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; galaxy, center; infrared, ISM, continuum ID FAR-INFRARED OBSERVATIONS; GALACTIC-CENTER REGION; RESOLUTION MAPS; EMISSION; DUST; LUMINOSITY; SAGITTARIUS; DENSITY; RING AB We present 10, 20, and 30 mu m maps of the central 60 '' x 90 '' (R.A. x decl.) of the Galaxy made at approximately 4 '' resolution with the NASA/Marshall Space Flight Center bolometer array. The maps span 2.5 x 3.8 pc centered near Sgr A IRS 1 and are the first to show the thermal emission from dust particles in both the ionized cavity and the neutral-gas ring with high sensitivity and an angular resolution as good as several arcseconds. In addition to warm dust associated with previously identified filaments in the central 40 '', these maps show the detailed distribution of dust along the entire Western Are of ionized gas at the inner edge of the neutral-gas ring. A prominent tongue of high 30 mu m optical depth extends from the northern part of the ring into the cavity near IRS 1, nearly bisecting the cavity; since we detect warm dust in this 30 mu m-emitting feature, which we call the Northern Intruder, it must be heated by radiation emitted in the cavity, thus confirming previous speculations based on far-infrared and O-0 observations that substantial neutral material protrudes into the cavity and may constitute infalling matter that fuels the central activity. We show that all the major ionized filaments (the Western Are, the Bar, the Northern Arm, and the Eastern Arm) are ionization fronts at the interfaces between low- and high-density regions, as had been previously demonstrated convincingly only for the Western Are. The locations of these ionization fronts are consistent with the dominant UV heating and ionizing sources being centrally located in the cavity. The derived dust temperatures strongly support this picture: they decrease away from the region of IRS 1 and Sgr A*, and they drop abruptly where the gas density increases at the ring. We determine that the total ultraviolet luminosity emitted by the central cluster and required to heat the dust to the inferred temperatures is 1.7 +/- 0.5 x 10(7) L., which agrees with our derived infrared luminosity. Half of this ultraviolet luminosity is absorbed by dust in the cavity, and more than 40% of the ultraviolet radiation that propagates to the edge of the cavity is absorbed by dust in the neutral-gas ring. C1 UNIV FLORIDA,DEPT ASTRON,GAINESVILLE,FL 32611. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SETI INST,MOFFETT FIELD,CA 94035. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Telesco, CM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,SSRB 211,GAINESVILLE,FL 32611, USA. NR 37 TC 42 Z9 43 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 JAN 10 PY 1996 VL 456 IS 2 BP 541 EP 556 DI 10.1086/176678 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100014 ER PT J AU Wall, WF Reach, WT Hauser, MG Arendt, RG Weiland, RG Weiland, JL Berriman, GB Bennett, CL Dwek, E Leisawitz, D Mitra, PM Odenwald, SF Sodroski, TJ Toller, GN AF Wall, WF Reach, WT Hauser, MG Arendt, RG Weiland, RG Weiland, JL Berriman, GB Bennett, CL Dwek, E Leisawitz, D Mitra, PM Odenwald, SF Sodroski, TJ Toller, GN TI COBE/DIRBE observations of the Orion constellation from the near- to far-infrared SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared, ISM continuum; radiative transfer ID MICRON EMISSION FEATURES; GIANT MOLECULAR CLOUDS; STAR-FORMING REGION; LAMBDA-ORIONIS; INTERSTELLAR DUST; SPIRAL GALAXIES; GAS; NEBULA; GRAINS; CO AB Observations by the DIRBE instrument aboard the COBE spacecraft, collected in 10 wavelength bands spanning the near-infrared to the far-infrared in a 0 degrees 7 beam, are presented for a region covering much of the Orion constellation. For an adopted distance of 450 pc, the total luminosity from dust (from 12 to 240 mu m) throughout the Orion A, Orion B, and lambda Ori fields, covering 16,900 pc(2), is similar to 10(6) Lo.. About 24%-36% of this dust luminosity is the result of dust heating by a general interstellar radiation field, with the rest resulting from heating by the Orion OB1 and lambda Ori OB associations. Given that the luminosity of the Orion OB1 and lambda Ori OB associations is 2.5 x 10(6) L., and also given that up to similar to 76% of dust luminosity is caused by dust heated primarily by the Orion stars, less than or similar to 30% of the stellar luminosity is trapped within the clouds and intercloud medium of Orion and reradiated at mid- to far-IR wavelengths. The near-IR (1.25, 2.2, 3.5, and 4.9 mu m) spectral distributions of the Orion Nebula and NGC 2024 indicate the presence of hot (T similar to few x 10(2) K) dust, both because of large I-V(4.9 mu m)/I-V(1.25 mu m) ratios and because of a substantial excess in the 3.5 mu m band relative to the intensities in the adjacent bands, some of which (greater than or similar to 30%) is caused by the 3.28 mu m emission line, commonly attributed to polycyclic aromatic hydrocarbons (PAHs). In the far-IR, the 100, 140, and 240 mu m intensities are consistent with a cool (usually 18-20 K, for emissivity index = 2) single-temperature component. The I-V(60 mu m)/I-V(100 mu m) color temperature is similar to 5-6 K higher than that from the cool component, suggesting that an additional warmer component or stochastically heated dust is contributing appreciably to the 60 mu m emission. Consequently, dust column densities derived from the 60 and 100 mu m intensities, assuming grains in thermal equilibrium, underestimate the dust-to-gas ratio by factors of 5-10. In contrast, the 140 and 240 mu m intensities yield dust column densities consistent with reasonable dust-to-gas mass ratios (i.e, similar to 0.01) to within a factor of 2. However, within this factor of 2, there appears to be a temperature-dependent systematic error in the dust column density derivation. The results of this paper may apply to external galaxies, since the region studied is more than 200 pc in size. All the above conclusions would have been obtained if the stars and clouds of Orion were placed at the distance of a nearby galaxy (similar to 1 Mpc) and observed in the DIRBE wavelength bands in an similar to 1' beam (provided the signal-to-noise ratio was unaffected). Hence, observations of the interstellar medium (ISM) in external galaxies that have resolutions of similar to 100 pc can still yield meaningful results. Further, if the stars and clouds in a spiral galaxy's arms can be represented by a series of Orion star and cloud complexes, one would expect the surface luminosity in the arms (for lambda=12-240 mu m) to be 2-4 times that in the interarm regions, averaged over 100 pc scales. C1 NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, APPL RES CORP, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, GEN SCI CORP, GREENBELT, MD 20771 USA. RP Wall, WF (reprint author), INST NACL ASTROFIS OPT & ELECTR, APDO POSTAL 51 & 216, PUEBLA, MEXICO. RI Dwek, Eli/C-3995-2012; OI Reach, William/0000-0001-8362-4094 NR 83 TC 16 Z9 16 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1996 VL 456 IS 2 BP 566 EP 597 DI 10.1086/176680 PN 1 PG 32 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100016 ER PT J AU Hollis, JM VanBuren, D Vogel, SN Feibelman, WA Jacoby, GH Pedelty, JA AF Hollis, JM VanBuren, D Vogel, SN Feibelman, WA Jacoby, GH Pedelty, JA TI The Abell 35 nebula inside out SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, structure; planetary nebulae, individual (Abell 35); shock waves; ultraviolet, ISM ID H-II REGIONS; MASS-LOSS; STARS; NUCLEUS; BUBBLES; BINARY; GALAXY; ALPHA AB We present deep 6 cm continuum and narrowband optical emission-line images in H alpha lambda 6563, [O III] lambda 5007, [O II] lambda 3727, and [N II] lambda 6584 of the Abell 35 planetary nebula (PN), showing its unique features. First, surrounding the central binary system, there is a bow shock, best seen predominantly in [O III], possibly weakly in H alpha, and not at all in [O II], [N II], or 6 cm continuum. Fabry-Perot [O III] data are also presented which constrain the bow shock kinematical parameters. Second, external to the central bow shock, there are two prominent parallel nebular features (the ''pipes''), seen at 6 cm continuum and in H alpha, [O II], and [N II], which suggest dynamical interaction between the nebular material and the interstellar medium. Fabry-Perot [N II] data provide the kinematical parameters for the pipes. Archival IUE spectra are also presented which indicate that the temperature due to the hot companion with its accretion disk is on the order of 150,000 K. We derive a mass-loss rate of less than or equal to 3.0 x 10(-10) M. yr(-1), a systemic wind velocity of greater than or equal to 530 km s(-1), and a total nebular mass of similar to 0.23 M.. We discuss the data presented here in the context of a binary system with a systemic wind moving at Mach 1.3 with respect to the PN medium to give rise to the bow shock morphology. Further, we also discuss the PN-ISM interaction as a Mach 10 shock which gives rise to two prominent linear features as a result of an inhomogeneous PN ejection mechanism. C1 CALTECH,CTR INFRARED PROC & ANAL,PASADENA,CA 91125. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. KITT PEAK NATL OBSERV,TUCSON,AZ 85726. NASA,GODDARD SPACE FLIGHT CTR,HIGH PERFORMANCE COMP BRANCH,GREENBELT,MD 20771. RP Hollis, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DIV SPACE DATA & COMP,CODE 930,GREENBELT,MD 20771, USA. NR 31 TC 18 Z9 18 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 JAN 10 PY 1996 VL 456 IS 2 BP 644 EP & DI 10.1086/176685 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100021 ER PT J AU Shore, SN Kenyon, SJ Starrfield, S Sonneborn, G AF Shore, SN Kenyon, SJ Starrfield, S Sonneborn, G TI On the interpretation of the ultraviolet spectra of symbiotic stars and recurrent novae .2. The 1985 outburst of RS Ophiuchi SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, symbiotic; galaxies, active; galaxies, nuclei; novae, cataclysmic variables; stars, individual (RS Ophiuchi) ID U-SCORPII; RADIO OBSERVATIONS; RR-TELESCOPII; LINE LIST; III LINES; MODELS; IUE; EVOLUTION; REMNANTS; TEL AB We discuss the 1985 outburst of the symbiotic recurrent nova RS Oph using spectra obtained with the International Ultraviolet Explorer satellite and contemporaneous ground-based optical spectra. The low-resolution integrated fluxes show that a short-lived constant bolometric luminosity phase existed in the early outburst. If this reached the Eddington luminosity, it implies a minimum mass for the white dwarf of 1.2 M.. This and the lack of evidence for eclipses in ultraviolet low-resolution spectra obtained in quiescence support the orbital solution of Dobrzycka & Kenyon (1994), in particular the low inclination of the system and the low mass, 0.5 M., of the red giant. The high-resolution optical and ultraviolet line profiles showed the development of two separate contributors. One was a broad-line component produced by emission from the high-velocity ejecta. The other was a narrow-line component produced in the portion of the red giant wind that was ionized by the UV pulse from the explosion and by radiation from the shock produced by the passage of the ejecta through the wind. The expanding Stromgren sphere had two effects. The strength of the line absorption from the overlying wind decreased against the ejecta and the ionized emitting gas, and the emission measure increased within the expanding H II region. We model these effects using the techniques developed in Shore & Aufdenberg (1993) to show how the column density of the cool material decreased with time. We show that the increased ionization of the wind accounts for changes in the absorption line components in the ultraviolet and use this decrease and the narrow emission-line ratios to determine the physical parameters for the line-forming region in the wind. From this, we derive the mass-loss rate for the red giant. In addition, we find evidence for a nitrogen overabundance in the wind using the time development of the N v 1240 Angstrom doublet. The primary source for ionizing the red giant wind was radiation produced by the shocked ejecta as they traversed the stellar wind. The shock-generated emission also produced and powered the coronal species until about 100 days after ourburst at which time shock breakout occurred. The ionized wind subsequently recombined, although a hot source was still present on the white dwarf on the basis of continued visibility of the ultraviolet O III fluorescence lines and the IR He I 1.08 mu m line. Finally, we discuss how many of the techniques developed in this study of a photoionizing pulse propagating into a dense environment can be applied to the analysis of active galactic nuclei. C1 HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP Shore, SN (reprint author), INDIANA UNIV, DEPT PHYS & ASTRON, 1700 MISHAWAKA AVE, S BEND, IN 46634 USA. OI Kenyon, Scott/0000-0003-0214-609X NR 70 TC 49 Z9 49 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1996 VL 456 IS 2 BP 717 EP 737 DI 10.1086/176692 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100028 ER PT J AU Singh, KP White, NE Drake, SA AF Singh, KP White, NE Drake, SA TI Corona(e) of AR Lacertae .1. The temperature and abundance distribution SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, eclipsing; stars, abundances; stars, coronae; stars, individual (AR Lacertae); X-rays, stars ID X-RAY-EMISSION; CANUM VENATICORUM BINARIES; STARS; FLARES AB X-ray spectra of the RS CVn binary AR Lac, obtained from simultaneous observations with the ROSAT PSPC and the ASCA SIS and GIS detectors, have been analyzed to study the coronal temperature and abundance distribution. The spectra were jointly fitted with plasma emission models to the following possible temperature distributions: (a) one with discrete multitemperature emission components, (b) a continuous emission measure with a power-law dependence on temperature, and (c) a continuous emission distribution parameterized by the sum of a sixth-order Chebyshev polynomial. We find that (i) solar abundance plasma models with either discrete or continuous emission measure (GEM) distributions are rejected, (ii) the best fit is obtained with a two-temperature (2T) plasma emission model with an underabundance of the elements O, Mg, Si, S, Ar, Ca, and Fe by a factor of 3-4 relative to the solar photospheric values, and (iii) the best-fit CEM distribution also has similarly reduced abundances but fits the data less well than the 2T model. These results are confirmed even when the Fe-L region, which is subject to uncertainties in the atomic physics, is excluded from the fit. We consider optical depth effects as unlikely to be the explanation for the observed weakness of the line complexes relative to the continuum. Analysis of the spectral data during the primary and secondary eclipses shows that the emission measure of the high-temperature component in the 2T models appears to be more affected by the primary eclipse than the low-temperature component, suggesting that part of the former is concentrated in structures that are spatially more compact. C1 NASA,GODDARD SPACE FLIGHT CTR,USRA,GREENBELT,MD 20771. RP Singh, KP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 660,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 46 TC 78 Z9 78 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 JAN 10 PY 1996 VL 456 IS 2 BP 766 EP 776 DI 10.1086/176695 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100031 ER PT J AU White, JC Schlegel, EM Honeycutt, RK AF White, JC Schlegel, EM Honeycutt, RK TI BT Monocerotis: Another extraordinary old nova SO ASTROPHYSICAL JOURNAL LA English DT Article DE novae, cataclysmic variables; stars, individual (BT Monocerotis) ID TIME-RESOLVED SPECTROPHOTOMETRY; CATACLYSMIC VARIABLES; ACCRETION DISKS; SEMIDETACHED BINARIES; WIND ACCRETION; GAS-DYNAMICS; 2A 0311-227; V471 TAURI; DWARF; COMPANION AB We present time-resolved spectrophotometry of the old nova BT Monocerotis (Nova Monocerotis 1939). While BT Mon's light curve possibly suggests the presence of an accretion disk, trailed spectrograms and Doppler tomograms of the data provide no such evidence. The spectra do reveal, however, high-velocity gas motions near eclipse that are of a character unique among other cataclysmic variables studied similarly to date. On the basis of the available data, we cannot describe the precise nature of BT Mon, but we suggest and discuss four possible interpretations of this extraordinary nova. Accretion by the system's white dwarf via the standard stream-disk mechanism is roughly supported by the appearance of BT Mon's light curve, yet our spectroscopy does not indicate the presence of an accretion disk. And while accretion by the white dwarf of a wind from the secondary star might explain the high-velocity gas motions we observe surrounding eclipse, our spectroscopy provides no evidence for a wind. A third possible interpretation of our and other's data for BT Mon involves two mass-transfer streams that emanate from the secondary star. One stream is the classical mass transfer stream; the other is a supersonic stream driven from the secondary star by a de Laval nozzle. This two-stream model explains the appearance of BT Mon's unusual, high-velocity gas motions visible during eclipse, but we find no additional evidence to support it. Finally, we consider the possibility that the system's white dwarf is highly magnetized, accretion occurring via an accretion column onto the primary star's surface. Our observations mildly support such an interpretation, and recent results from other magnetic cataclysmic variables strengthen this last interpretation. C1 UNIV SPACE RES ASSOC,GREENBELT,MD. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. INDIANA UNIV,DEPT ASTRON,BLOOMINGTON,IN 47405. NR 54 TC 8 Z9 8 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 JAN 10 PY 1996 VL 456 IS 2 BP 777 EP 787 DI 10.1086/176696 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN541 UT WOS:A1996TN54100032 ER PT J AU Carlstrom, JE Joy, M Grego, L AF Carlstrom, JE Joy, M Grego, L TI Interferometric imaging of the Sunyaev-Zeldovich effect at 30 GHz SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic background radiation; cosmology, observations galaxies, clusters, individual (CL 0016+16, A773, A1704); techniques, interferometric ID GALAXIES; CLUSTER AB We present high signal-to-noise ratio images of the Sunyaev-Zeldovich effect toward the clusters CL 0016+16 and Abell 773. A null result is reported for Abell 1704. The data were obtained with the millimeter array of the Owens Valley Radio Observatory outfitted with 30 GHz receivers. Isothermal models for the cluster gas with core radii spanning 20 ''-100 '' were fitted to the visibility data. The results suggest the central decrement Delta T-0 lies within the range -700 to -820 mu K for CL 0016+16 and -575 to -760 mu K for Abell 773, corresponding to Compton y-values of 1.3-1.5 x 10(-4) and 1.1-1.4 x 10(-4), respectively. A comparison of the image of the Sunyaev-Zeldovich effect toward CL 0016+16 with a ROSAT image of the X-ray emission shows good correspondence; the positions agree within the uncertainties, and both images show resolved structure elongated at a position angle of similar to 50 degrees. Using the core radius and ellipticity derived from the X-ray data to constrain the model parameters resulted in a decrement for CL 0016+16 of Delta T-0 = -717 +/- 65 mu K. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP Carlstrom, JE (reprint author), CALTECH,DIV PHYS MATH & ASTRON,MS 105-24,PASADENA,CA 91125, USA. NR 20 TC 100 Z9 100 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 JAN 10 PY 1996 VL 456 IS 2 BP L75 EP & PN 2 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN544 UT WOS:A1996TN54400002 ER PT J AU Cheng, ES Cottingham, DA Fixsen, DJ Inman, CA Kowitt, MS Meyer, SS Page, LA Puchalla, JL Ruhl, JE Silverberg, RF AF Cheng, ES Cottingham, DA Fixsen, DJ Inman, CA Kowitt, MS Meyer, SS Page, LA Puchalla, JL Ruhl, JE Silverberg, RF TI MSAM1-94: Repeated measurement of medium-scale anisotropy in the cosmic microwave background radiation SO ASTROPHYSICAL JOURNAL LA English DT Article DE balloons; cosmic microwave background; cosmology, observations AB The second flight of the Medium-Scale Anisotropy Measurement (MSAM1-94) observed the same field as the first flight (MSAM1-92) to confirm our earlier measurement of cosmic microwave background radiation (CMBR) anisotropy. This instrument chops a 30' beam in a three-position pattern with a throw of +/-40' and simultaneously measures single- and double-differenced sky signals. We observe in four spectral channels centered at 5.6, 9.0, 16.5, and 22.5 cm(-1),providing sensitivity to the peak of the CMBR and to thermal emission from interstellar dust. The dust component correlates well with the IRAS 100 mu m map. The CMBR observations in our double-difference channel correlate well with the earlier observations, but the single-difference channel shows some discrepancies. We obtain a detection of fluctuations in the MSAM1-94 data set that match CMBR in our spectral bands of Delta T/T = 1.9(-0.7)(+1.3) x 10(-5) (90% confidence interval, including calibration uncertainty) for total rms Gaussian fluctuations with correlation angle 0.degrees 3, using the double-difference demodulation. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,APPL RES CORP,GREENBELT,MD 20771. UNIV CHICAGO,ENRICO FERMI INST,CHICAGO,IL 60637. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. RP Cheng, ES (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GLOBAL SCI & TECHNOL INC,CODE 6850,GREENBELT,MD 20771, USA. NR 18 TC 36 Z9 36 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 JAN 10 PY 1996 VL 456 IS 2 BP L71 EP L74 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN544 UT WOS:A1996TN54400001 ER PT J AU Ofman, L Davila, JM AF Ofman, L Davila, JM TI Nonlinear excitation of global modes and heating in randomly driven coronal loops SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun, corona; Sun, magnetic fields; waves ID RESONANT ABSORPTION; WAVES AB We solve the nonlinear three-dimensional MHD equations for fully compressible, low-beta, resistive plasma to model resonant Alfven wave heating of a coronal loop. Alfven waves are driven in the loop by a (pseudo)random time-dependent forcing with a bounded amplitude. We find that global modes are excited and resonantly heat the loop in the nonlinear regime in three dimensions. Resonant heating occurs in several narrow layers accompanied by high velocity and magnetic field shear. The narrow dissipation layers are affected by the self-consistent velocity shear and are carried around by the flow. Consequently, the topology of the perpendicular magnetic field and the ohmic heating regions differs significantly from the linear or single-frequency driver regimes, and the heating is spread more uniformly inside the loop. The heating rate varies significantly on a timescale of one to several global mode periods. We conclude that, in solar active regions, random field-line motions can excite global mode oscillations and resonantly heat the loops with a time-varying heating rate. C1 HUGHE STX CORP,GREENBELT,MD. RP Ofman, L (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 14 TC 23 Z9 23 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 JAN 10 PY 1996 VL 456 IS 2 BP L123 EP L126 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN544 UT WOS:A1996TN54400013 ER PT J AU Steininger, MK AF Steininger, MK TI Tropical secondary forest regrowth in the Amazon: Age, area and change estimation with Thematic Mapper data SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID UPPER RIO NEGRO; SATELLITE DATA; VEGETATION INDEX; BURN AGRICULTURE; LAND-USE; REFLECTANCE; SUCCESSION; DEFORESTATION; MODEL; IMAGES AB The purpose of this study is to assess the potential of estimating the area, age and changes of tropical secondary forest regrowth from the Landsat Thematic Mapper (TM). Sites of mature forest, agriculture, pasture, pasture with remnant trees, and stands of secondary forest regrowth from 2 to 19 years of age were surveyed in two study areas near Manaus, Amazonas, Brazil, and mapped to the TM imagery. Considerable changes in spectral reflectance were observed over the first 19 years of regrowth, and these can be summarized by indices related to canopy brightness and greenness. The near-infrared reflectance, the difference index, Kauth-Thomas greenness, and percentage leaf cover all increase over the first 4 years after abandonment, peak from 4 to 8 years, and decrease from 8 to 13 years. The Normalized Difference Vegetation Index (NDVI) rapidly rises over the first 4 years, and displays no apparent relation to stand age thereafter. The brightness of regrowth canopies decreases from 8 to 13 years. Stands from 13 to 19 years-old are spectrally similar to mature forest. All regrowth age classes are spectrally distinct from agriculture and pasture, and all regrowth age classes younger than 14 years are spectrally distinct from mature forest. Spectral indices of canopy brightness are significantly correlated with regrowth stand age (r(2) less than or equal to 0.48, p < 0.001). Based on field research in several areas of Amazonia, these spectral patterns can be explained in terms of temporal changes in canopy geometry and leaf area. The estimated rates of regrowth clearance and reversion to regrowth between 1988 and 1991 suggest the intensity of rotational agriculture practised by both communities. These results suggest that monitoring tropical secondary regrowth with TM imagery could substantially improve estimates of carbon sequestration subsequent to tropical deforestation. RP Steininger, MK (reprint author), UNIV MARYLAND, DEPT GEOG, NASA, LANDSAT PATHFINDER TROP DEFORESTAT PROJECT, COLLEGE PK, MD 20742 USA. NR 69 TC 110 Z9 113 U1 3 U2 18 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 JAN 10 PY 1996 VL 17 IS 1 BP 9 EP 27 PG 19 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA TT833 UT WOS:A1996TT83300002 ER PT J AU Johnson, JM Satake, K Holdahl, SR Sauber, J AF Johnson, JM Satake, K Holdahl, SR Sauber, J TI The 1964 Prince William Sound earthquake: Joint inversion of tsunami and geodetic data SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GREAT EARTHQUAKES; SUBDUCTION ZONES; P-WAVES; ALASKA; PLATE AB The 1964 Prince William Sound (Alaska) earthquake, M(w) = 9.2, ruptured a large area beneath the continental margin of Alaska from Prince William Sound to Kodiak Island. A joint inversion of tsunami waveforms and geodetic data, consisting of vertical displacements and horizontal vectors, gives a detailed slip distribution. Two areas of high slip correspond to seismologically determined areas of high moment release: the Prince William Sound asperity with average slip of 18 m and the Kodiak asperity with average slip of 10 m. The average slip on the fault is 8.6 m and the seismic moment is estimated as 6.3 x 10(22) N m, or over 75% of the seismic moment determined from long-period surface waves. C1 NOAA, NATL OCEAN SERV, COAST & GEODET SURVEY, NATL GEODET SURVEY, SILVER SPRING, MD 20910 USA. NASA, GODDARD SPACE FLIGHT CTR, TERR PHYS LAB, GEODYNAM BRANCH, GREENBELT, MD 20771 USA. RP Johnson, JM (reprint author), UNIV MICHIGAN, DEPT GEOL SCI, 2534 CC LITTLE BLDG, ANN ARBOR, MI 48109 USA. RI Satake, Kenji/E-2312-2011; Sauber, Jeanne/D-7684-2012 OI Satake, Kenji/0000-0002-3368-3085; NR 36 TC 102 Z9 102 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 10 PY 1996 VL 101 IS B1 BP 523 EP 532 DI 10.1029/95JB02806 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TQ276 UT WOS:A1996TQ27600002 ER PT J AU Molnar, P Gipson, JM AF Molnar, P Gipson, JM TI A bound on the rheology of continental lithosphere using very long baseline interferometry: The velocity of south China with respect to Eurasia SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID LINE INTERFEROMETRY; CENOZOIC TECTONICS; ASIA; DEFORMATION; COLLISION; TIBET; MOTIONS; REGIONS; EARTHQUAKE; QUATERNARY AB Very long baseline interferometric (VLBI) measurements using the antenna near Shanghai, China, between 1987 and 1994 show that this site moves at 8 +/- 0.5 mm/yr (1 sigma) in the direction N116.5 degrees E (+/- 4.1 degrees) with respect to VLBI sites in Europe on the Eurasia plate. Independent measurements of the site at Shanghai with respect to sites on nearly all major plates (Eurasist, North America, Pacific, Australia, and Africa) determine this velocity. South China translates east-southeast relative to Eurasia more slowly than 20% of India's roughly 50 mm/yr convergence rate with Eurasia and hence accommodates only a small fraction of India's penetration into Eurasia. Apparently, crustal thickening absorbs most of India's convergence. The relatively low speed of south China supports treatments of continental lithosphere as a thin viscous sheet whose strength is governed primarily by power law creep in the upper mantle, and not by friction in the crust. C1 NASA, GODDARD SPACE FLIGHT CTR, NVI INC, GREENBELT, MD 20771 USA. RP Molnar, P (reprint author), MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02139 USA. NR 41 TC 39 Z9 49 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 10 PY 1996 VL 101 IS B1 BP 545 EP 553 DI 10.1029/95JB02503 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TQ276 UT WOS:A1996TQ27600004 ER PT J AU Crowley, JK Hook, SJ AF Crowley, JK Hook, SJ TI Mapping playa evaporite minerals and associated sediments in Death Valley, California, with multispectral thermal infrared images SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID EMISSIVITY AB Efflorescent salt crusts and associated sediments in Death Valley, California, were studied with remote-sensing data acquired by the NASA thermal infrared multispectral scanner (TIMS). Nine spectral classes that represent a variety of surface materials were distinguished, including several classes that reflect important aspects of the playa groundwater chemistry and hydrology. Evaporite crusts containing abundant thenardite (sodium sulfate) were mapped along the northern and eastern margins of the Cottonball Basin, areas where the inflow waters are rich in sodium. Gypsum (calcium sulfate) crusts were more common in the Badwater Basin, particularly near springs associated with calcic groundwaters along the western basin margin. Evaporite-rich crusts generally marked areas where groundwater is periodically near the surface and thus able to replenish the crusts though capillary evaporation. Detrital silicate minerals were prevalent in other parts of the salt pan where shallow groundwater does not affect the surface composition. The surface features in Death Valley change in response to climatic variations on several different timescales. For example, salt crusts on low-lying mudflats form and redissolve during seasonal-to-interannual cycles of wetting and desiccation. In contrast, recent flooding and erosion of rough-salt surfaces in Death Valley probably reflect increased regional precipitation spanning several decades. Remote-sensing observations of playas can provide a means for monitoring changes in evaporite facies and for better understanding the associated climatic processes. At present, such studies are limited by the availability of suitable airborne scanner data. However, with the launch of the Earth Observing System (EOS) AM-1 Platform in 1998, multispectral visible/near-infrared and thermal infrared remote-sensing data will become globally available. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Crowley, JK (reprint author), US GEOL SURVEY, MS 927, RESTON, VA 22092 USA. NR 42 TC 60 Z9 62 U1 4 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 10 PY 1996 VL 101 IS B1 BP 643 EP 660 DI 10.1029/95JB02813 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TQ276 UT WOS:A1996TQ27600011 ER PT J AU Schwiebert, L Jayasimha, DN AF Schwiebert, L Jayasimha, DN TI A necessary and sufficient condition for deadlock-free wormhole routing SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article ID INTERCONNECTION NETWORKS AB An important open problem in wormhole routing has been to find a necessary and sufficient condition for deadlock-free adaptive routing. Recently, Duato has solved this problem for a restricted class of adaptive routing algorithms. In this paper, a necessary and sufficient condition is proposed that can be used for any adaptive or nonadaptive routing algorithm for wormhole routing, as long as only local information is required for routing. The underlying proof technique introduces a new type of dependency graph, the channel waiting graph, which omits most channel dependencies that cannot be used to create a deadlock configuration. The necessary and sufficient condition can be applied in a straightforward manner to most routing algorithms. This is illustrated by proving deadlock freedom for a partially adaptive nonminimal mesh routing algorithm that does not require virtual channels and a fully adaptive minimal hypercube routing algorithm with two virtual channels per physical channel. Both routing algorithms are more adaptive than any previously proposed routing algorithm with similar virtual channel requirements. (C) 1996 Academic Press, Inc. C1 NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP Schwiebert, L (reprint author), OHIO STATE UNIV, DEPT COMP & INFORMAT SCI, 2015 NEIL AVE, COLUMBUS, OH 43210 USA. NR 30 TC 36 Z9 37 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD JAN 10 PY 1996 VL 32 IS 1 BP 103 EP 117 DI 10.1006/jpdc.1996.0008 PG 15 WC Computer Science, Theory & Methods SC Computer Science GA TU671 UT WOS:A1996TU67100008 ER PT J AU Kinder, JD Youngs, WJ AF Kinder, JD Youngs, WJ TI Preparation and structural characterization of a platinum catecholate complex containing two 3-ethynylthiophene groups SO ORGANOMETALLICS LA English DT Article ID TRANSITION-METAL COMPLEXES; ADENINE-DINUCLEOTIDE; CHARGE-DISTRIBUTION; REDOX PROPERTIES; MULTIPLE BONDS; LIGANDS; SEMIQUINONE; SERIES; DERIVATIVES; ELECTRODES AB The reaction of 1,2-bis(tert-butyldimethylsiloxy)-3,4-bis(3-ethynylthiophene-yl)benzene (4) with Pt(P(Ph)(3))(2)Cl-2 and tetrabutylammonium fluoride produces a novel platinum catecholate complex. C1 UNIV AKRON,DEPT CHEM,AKRON,OH 44325. RP Kinder, JD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 27 TC 16 Z9 16 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD JAN 9 PY 1996 VL 15 IS 1 BP 460 EP 463 DI 10.1021/om950155t PG 4 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA TP751 UT WOS:A1996TP75100067 ER PT J AU Gleiser, M Heckler, AF AF Gleiser, M Heckler, AF TI Nonperturbative effects on nucleation SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTROWEAK PHASE-TRANSITION; FALSE VACUUM; DECAY; FATE AB A nonperturbative correction to the thermal nucleation rate of critical bubbles in a first-order phase transition is estimated. Using a simple model of a scalar field in a double-well potential, we obtain a corrected potential which incorporates the free-energy density available from large-amplitude fluctuations, which is not included in the usual perturbative calculation. As an application of our method, we show how these corrections can both qualitatively and quantitatively explain anomalously high nucleation rates observed in 2D numerical simulations. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Gleiser, M (reprint author), DARTMOUTH COLL,DEPT PHYS & ASTRON,HANOVER,NH 03755, USA. RI Heckler, Andrew/A-7291-2010 OI Heckler, Andrew/0000-0001-5494-7855 NR 17 TC 21 Z9 21 U1 0 U2 0 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 JAN 8 PY 1996 VL 76 IS 2 BP 180 EP 183 DI 10.1103/PhysRevLett.76.180 PG 4 WC Physics, Multidisciplinary SC Physics GA TN761 UT WOS:A1996TN76100006 ER PT J AU Zhang, ZY Monks, PS Stief, LJ Liebman, JF Huie, RE Kuo, SC Klemm, RV AF Zhang, ZY Monks, PS Stief, LJ Liebman, JF Huie, RE Kuo, SC Klemm, RV TI Experimental determination of the ionization energy of IO(X(2)Pi(3/2)) and estimations of Delta H-f degrees(0)(IO+) and PA(IO) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON RESONANCE SPECTRA; BOND-DISSOCIATION ENERGIES; PHOTOELECTRON-SPECTROSCOPY; PHOTOIONIZATION SPECTRUM; IO; BRO; PHOTODISSOCIATION; KINETICS; RADICALS; CF3I AB Photoionization efficiency (PIE) spectra of IO(X(2) Pi(i)) were measured over the wavelength range lambda = 115.0-130.0 nm and in the ionization threshold region lambda = 126.0-130.0 nm, using a discharge flow-photoionization mass spectrometer apparatus coupled to a synchrotron radiation source. Iodine oxide was generated by the reactions of O(P-3) atoms with I-2 and CF3I. The PIE spectra displayed step-function behavior. From the half-rise point of the initial step, a value of 9.73(5) +/- 0.01(7) eV was obtained for the adiabatic ionization energy IE) of IO, corresponding to the IO+(X(3) Sigma(-)) <-- IO(X(2) Pi(3/2)) transition. As this appears to be the first experimental determination of IE(IO), a trend analysis has been employed to provide further insight into the experimentally derived value. The separation between the first two steps in the PIE spectrum (which might be perturbed slightly due to autoionization) was used to derive the vibrational spacing of the cation, 1060 +/- 160 cm(-1). A Rydberg progression, presumably converging to the excited (1) Delta state of the cation, has a convergence limit that lies 0.596 eV above the ground state of the cation. A selected value for the bond dissociation energy of IO, D-0(o)(IO) = 226 kJ mol(-1), leads to Delta(f)H(0)(o)(IO) = 128 i 4 kJ mol(-1). From this value for the heat of formation of IO, estimates are made for Delta(f)H(0)(o)(IO+), Delta(f)H(0)(o)(HOI) and the proton affinity of IO. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB CODE 690,GREENBELT,MD 20771. UNIV MARYLAND,DEPT CHEM & BIOCHEM,BALTIMORE,MD 21228. BROOKHAVEN NATL LAB,UPTON,NY 11973. NIST,DIV CHEM KINET & THERMODYNAM,GAITHERSBURG,MD 20899. RI Huie, Robert/A-5645-2010; Monks, Paul/H-6468-2016 OI Monks, Paul/0000-0001-9984-4390 NR 65 TC 20 Z9 20 U1 0 U2 2 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 JAN 4 PY 1996 VL 100 IS 1 BP 63 EP 68 DI 10.1021/jp952405p PG 6 WC Chemistry, Physical SC Chemistry GA TN839 UT WOS:A1996TN83900012 ER PT J AU Zhang, RY Leu, MT Keyser, LF AF Zhang, RY Leu, MT Keyser, LF TI Heterogeneous chemistry of HONO on liquid sulfuric acid: A new mechanism of chlorine activation on stratospheric sulfate aerosols SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ANTARCTIC OZONE; PHYSICAL-CHEMISTRY; SYSTEM; ERUPTION; PINATUBO AB Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO+HSO4-). At temperatures below 230 K, NO+HSO4- was observed to be stable and accumulated in concentrated solutions (>70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (<70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (CINO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4 In the stratosphere, CINO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT. RP Zhang, RY (reprint author), CALTECH, JET PROP LAB, DIV EARTH & SPACE SCI, PASADENA, CA 91109 USA. RI Zhang, Renyi/A-2942-2011 NR 45 TC 57 Z9 59 U1 5 U2 8 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 JAN 4 PY 1996 VL 100 IS 1 BP 339 EP 345 DI 10.1021/jp952060a PG 7 WC Chemistry, Physical SC Chemistry GA TN839 UT WOS:A1996TN83900051 ER PT B AU Sterling, T Becker, DJ Savarese, D Berry, MR Reschke, C AF Sterling, T Becker, DJ Savarese, D Berry, MR Reschke, C GP IEEE TI Achieving a balanced low-cost architecture for mass storage management through multiple fast ethernet channels on the Beowulf parallel workstation SO 10TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM - PROCEEDINGS OF IPPS '96 LA English DT Proceedings Paper CT 10th International Parallel Processing Symposium (IPPS 96) CY APR 15-19, 1996 CL HONOLULU, HI SP IEEE, Comp Soc, Assoc Comp Machinery, SIGARCH, Cambridge Parallel Proc, Ctr Dev Adv Comp, Cray Res Inc, Electr & Telecommun Res Inst, IBM Syst 390 Div, Litton Guidance & Control Syst Inc, Mercury Comp Syst Inc, Portland Grp Inc, Tandem Comp Inc, Virtual Comp Corp C1 NASA,GODDARD SPACE FLIGHT CTR,CTR EXCELLENCE SPACE DATA & INFORMAT SCI,GREENBELT,MD 20771. NR 0 TC 1 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7255-2 PY 1996 BP 104 EP 108 DI 10.1109/IPPS.1996.508045 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BF67V UT WOS:A1996BF67V00015 ER PT B AU Ding, HQ Ferraro, RD AF Ding, HQ Ferraro, RD GP IEEE TI An element-based concurrent partitioner for unstructured finite element meshes SO 10TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM - PROCEEDINGS OF IPPS '96 LA English DT Proceedings Paper CT 10th International Parallel Processing Symposium (IPPS 96) CY APR 15-19, 1996 CL HONOLULU, HI SP IEEE, Comp Soc, Assoc Comp Machinery, SIGARCH, Cambridge Parallel Proc, Ctr Dev Adv Comp, Cray Res Inc, Electr & Telecommun Res Inst, IBM Syst 390 Div, Litton Guidance & Control Syst Inc, Mercury Comp Syst Inc, Portland Grp Inc, Tandem Comp Inc, Virtual Comp Corp C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 1 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7255-2 PY 1996 BP 601 EP 605 DI 10.1109/IPPS.1996.508118 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BF67V UT WOS:A1996BF67V00089 ER PT B AU Saini, S AF Saini, S GP IEEE TI NAS experiences of porting CM Fortran codes to HPF on IBM SP2 and SGI Power Challenge SO 10TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM - PROCEEDINGS OF IPPS '96 LA English DT Proceedings Paper CT 10th International Parallel Processing Symposium (IPPS 96) CY APR 15-19, 1996 CL HONOLULU, HI SP IEEE, Comp Soc, Assoc Comp Machinery, SIGARCH, Cambridge Parallel Proc, Ctr Dev Adv Comp, Cray Res Inc, Electr & Telecommun Res Inst, IBM Syst 390 Div, Litton Guidance & Control Syst Inc, Mercury Comp Syst Inc, Portland Grp Inc, Tandem Comp Inc, Virtual Comp Corp C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7255-2 PY 1996 BP 873 EP 880 DI 10.1109/IPPS.1996.508194 PG 8 WC Computer Science, Theory & Methods SC Computer Science GA BF67V UT WOS:A1996BF67V00133 ER PT J AU Bell, TL Kundu, PK Kummerow, C AF Bell, TL Kundu, PK Kummerow, C GP AMER METEOROL SOC TI Sampling error of satellite estimates of gridded rainfall SO 13TH CONFERENCE ON PROBABILITY AND STATISTICS IN THE ATMOSPHERIC SCIENCES LA English DT Proceedings Paper CT 13th Conference on Probability and Statistics in the Atmospheric Sciences CY FEB 21-23, 1996 CL SAN FRANCISCO, CA SP Amer Meteorol Soc RP Bell, TL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 913,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1996 BP 296 EP 300 PG 5 WC Mathematics, Applied; Meteorology & Atmospheric Sciences; Statistics & Probability SC Mathematics; Meteorology & Atmospheric Sciences GA BH10R UT WOS:A1996BH10R00055 ER PT J AU Smith, GL ManaloSmith, N AF Smith, GL ManaloSmith, N GP AMER METEOROL SOC TI On the effects of scene-identification errors on Earth radiant flux determination SO 13TH CONFERENCE ON PROBABILITY AND STATISTICS IN THE ATMOSPHERIC SCIENCES LA English DT Proceedings Paper CT 13th Conference on Probability and Statistics in the Atmospheric Sciences CY FEB 21-23, 1996 CL SAN FRANCISCO, CA SP Amer Meteorol Soc RP Smith, GL (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1996 BP 301 EP 307 PG 7 WC Mathematics, Applied; Meteorology & Atmospheric Sciences; Statistics & Probability SC Mathematics; Meteorology & Atmospheric Sciences GA BH10R UT WOS:A1996BH10R00056 ER PT B AU Abrahams, MD Rivera, G Ames, CK AF Abrahams, MD Rivera, G Ames, CK GP AIAA/IEEE TI Trials and tribulation of implementing intranet technology: The Cassini Information Access System SO 15TH DASC - AIAA/IEEE DIGITAL AVIONICS SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 15th AIAA/IEEE Digital Avionics Systems Conference (15th DASC) CY OCT 27-31, 1996 CL ATLANTA, GA SP AIAA, IEEE AB The Cassini Information Access System (IAS) was built to provide Cassini Integration and Test engineers with ready access to current technical and logistical project information. World Wide Web (WWW) technology was used to provide a consistent user interface to pre-existing interactive systems as well as new repositories and interactive services developed specifically for Cassini. A Web ''gateway'' was developed for each pre-existing data service. Each service had its unique requirements including read only and read and write access to SQL databases. Other requirements called for development of many background processes to handle the access of data produced by proprietary databases and non-database data repositories. Through the use of the WWW, anonymous ftp, Novell services, and unique data conversion programs, we were able to put the system into limited operation by August 1995 and full operation by March 1996. RP Abrahams, MD (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3386-1 PY 1996 BP 11 EP 15 DI 10.1109/DASC.1996.559126 PG 5 WC Engineering, Aerospace SC Engineering GA BG78Z UT WOS:A1996BG78Z00002 ER PT B AU Johnson, SC Chin, DK Rovinsky, RB Kostiuk, PF Lee, DA Hemm, RV Wingrove, ER AF Johnson, SC Chin, DK Rovinsky, RB Kostiuk, PF Lee, DA Hemm, RV Wingrove, ER GP AIAA/IEEE TI Reduction of weather-related terminal area delays in the free-flight era SO 15TH DASC - AIAA/IEEE DIGITAL AVIONICS SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 15th AIAA/IEEE Digital Avionics Systems Conference (15th DASC) CY OCT 27-31, 1996 CL ATLANTA, GA SP AIAA, IEEE AB While much of the emphasis of the free-flight movement has been concentrated on reducing en-route delays, airport capacity is a major bottleneck in the current airspace system, particularly during bad weather. According to the Air Transport Association (ATA) Air Carrier Delay Reports, ground delays (gate-hold, taxi-in, and taxi-out) comprise 75 percent of total delays. It is likely that the projected steady growth in traffic will only exacerbate these losses. Preliminary analyses show that implementation of the terminal area technologies and procedures under development in NASA's Terminal Area Productivity program can potentially save the airlines at least $350M annually in weather-related delays by the year 2005 at Boston Logan and Detroit airports alone. This paper briefly describes the Terminal Area Productivity program, outlines the cost/benefit analyses that are being conducted in support of the program, and presents some preliminary analysis results. RP Johnson, SC (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3386-1 PY 1996 BP 185 EP 190 DI 10.1109/DASC.1996.559155 PG 6 WC Engineering, Aerospace SC Engineering GA BG78Z UT WOS:A1996BG78Z00026 ER PT B AU Riley, AL Kayalar, S Mittskus, A Antsos, D Grigorian, E Olson, E Neal, J Satorius, E Kermode, A AF Riley, AL Kayalar, S Mittskus, A Antsos, D Grigorian, E Olson, E Neal, J Satorius, E Kermode, A GP AIAA/IEEE TI New millennium deep space tiny transmitter: First phase of a digital transponder SO 15TH DASC - AIAA/IEEE DIGITAL AVIONICS SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 15th AIAA/IEEE Digital Avionics Systems Conference (15th DASC) CY OCT 27-31, 1996 CL ATLANTA, GA SP AIAA, IEEE AB An advanced technology X- and Ka-band (8 and 32 GHz) Tiny Transmitter is being developed for the New Millenniun program and is described in this paper. The Tiny Transmitter is the first development phase of the Tiny Transponder which will incorporate recent advances in miniaturization and flexibility of radio systems by utilizing digital radio techniques. These techniques incorporate digital technology and algorithms to perform many functions which have traditionally been performed by analog circuits and allow the complexity of the RF portion of the radio to be minimized. The Tiny Transponder will be able to meet the needs of many deep space missions presently being planned for launch after the year 2000. RP Riley, AL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3386-1 PY 1996 BP 225 EP 230 DI 10.1109/DASC.1996.559163 PG 6 WC Engineering, Aerospace SC Engineering GA BG78Z UT WOS:A1996BG78Z00032 ER PT B AU Belcastro, CM AF Belcastro, CM GP AIAA/IEEE TI A low-cost comprehensive process for assessing electromagnetic environment (EME) effects on flight-critical control computers SO 15TH DASC - AIAA/IEEE DIGITAL AVIONICS SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 15th AIAA/IEEE Digital Avionics Systems Conference (15th DASC) CY OCT 27-31, 1996 CL ATLANTA, GA SP AIAA, IEEE AB A process is presented for assessing the effects of electromagnetic environments on flight-critical aircraft control computers. The assessment process is a combination of analysis, simulation, and tests and is currently under development for demonstration at the NASA Langley Research Center in the High Intensity Radiated Fields (HIRF) Laboratory and Closed-Loop Test (CLT) Laboratory. The assessment process is comprehensive in that it addresses (i) closed-loop operation of the controller under test, (ii) real-time dynamic detection of controller malfunctions that occur due to the effects of electromagnetic disturbances caused by lightning, HIRF, and electromagnetic interference and incompatibilities, and (iii) the resulting effects on the aircraft relative to the stage of flight, flight conditions, and required operational performance. In addition, this method uses electromagnetic field modeling codes to determine internal electromagnetic environments to which onboard electronic equipment will be subjected. Lower cost demonstrations of certification compliance should be realizable using this method due to the reduction or elimination of costly full-aircraft tests. RP Belcastro, CM (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 130,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3386-1 PY 1996 BP 443 EP 449 DI 10.1109/DASC.1996.559198 PG 7 WC Engineering, Aerospace SC Engineering GA BG78Z UT WOS:A1996BG78Z00064 ER PT B AU Dudley, KL AF Dudley, KL GP AIAA/IEEE TI A description of the hardware element of the NASA EME flight tests SO 15TH DASC - AIAA/IEEE DIGITAL AVIONICS SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 15th AIAA/IEEE Digital Avionics Systems Conference (15th DASC) CY OCT 27-31, 1996 CL ATLANTA, GA SP AIAA, IEEE AB In support of NASA's Fly-By-Light/Power-By-Wire (FBL/PBW) program, a series of flight tests were conducted by NASA Langley Research Center in February, 1995. The NASA Boeing 757 was flown past known RF transmitters to measure both external and internal radiated fields. The aircraft was instrumented with strategically located sensors for acquiring data on shielding effectiveness and internal coupling. The data are intended to support computational and statistical modeling codes used to predict internal field levels of an electromagnetic environment (EME) on an aircraft. The hardware, instrumentation, and sensors, forged the basis of the data acquisition system. The configuration of the hardware provided for accurate measurements of the electromagnetic environment during flight. The system operated at several specified frequencies and modulation schemes. Internal and external EME data were recorded by the acquisition equipment and additional flight parameters were acquired from the aircraft's flight data bus. This paper describes the flight instrumentation system on board the aircraft and concentrates on the hardware components employed during the EME flight test. Measurement instrumentation, sensors, and aircraft configurations, are illustrated and discussed. Particular attention is given to design, operation, and use of the hardware. The actualized flight test scenarios are discussed to give broader scope of the experiment, design requirements and philosophy are examined to highlight the quality and the limitations of the system, and flight data is presented as a representative sample of experiment results. RP Dudley, KL (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3386-1 PY 1996 BP 451 EP 456 DI 10.1109/DASC.1996.559199 PG 6 WC Engineering, Aerospace SC Engineering GA BG78Z UT WOS:A1996BG78Z00065 ER PT B AU Kim, MS Daughtry, CST Chappelle, EW McMurtrey, JE Corp, LA AF Kim, MS Daughtry, CST Chappelle, EW McMurtrey, JE Corp, LA BE Chang, JS Lee, JH Lee, SY Nam, CH TI Fluorescence imaging system (FIS): Function and use in the assessment of vegetation SO 17TH CONGRESS OF THE INTERNATIONAL COMMISSION FOR OPTICS: OPTICS FOR SCIENCE AND NEW TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th Congress of the International-Commission-for-Optics - Optics for Science and New Technology CY AUG 19-23, 1996 CL TAEJON, SOUTH KOREA SP Int Commiss Opt, Soc Photo Opt Instrumentat Engineers C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2164-2 J9 P SOC PHOTO-OPT INS PY 1996 VL 2778 BP 44 EP 45 PG 2 WC Optics SC Optics GA BG45E UT WOS:A1996BG45E00021 ER PT B AU Chappelle, E McMurtrey, JE Kim, MS Corp, L AF Chappelle, E McMurtrey, JE Kim, MS Corp, L BE Chang, JS Lee, JH Lee, SY Nam, CH TI Laser induced fluorescence (LIF) of intact plants in the remote assessment of the physiological status of vegetation SO 17TH CONGRESS OF THE INTERNATIONAL COMMISSION FOR OPTICS: OPTICS FOR SCIENCE AND NEW TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 17th Congress of the International-Commission-for-Optics - Optics for Science and New Technology CY AUG 19-23, 1996 CL TAEJON, SOUTH KOREA SP Int Commiss Opt, Soc Photo Opt Instrumentat Engineers C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2164-2 J9 P SOC PHOTO-OPT INS PY 1996 VL 2778 BP 733 EP 734 PG 2 WC Optics SC Optics GA BG45E UT WOS:A1996BG45E00357 ER PT B AU Newell, JM Larson, TW Gersch, G Stoklosa, M AF Newell, JM Larson, TW Gersch, G Stoklosa, M GP INT SOC HYBRID MICROELECTR TI Reliability modeling of MCMs - RELTECH lessons learned SO 1966 INTERNATIONAL CONFERENCE ON MULTICHIP MODULES, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1996 International Conference on Multichip Modules CY APR 17-19, 1996 CL DENVER, CO SP Int Soc Hybrid Microelectr, Microelectr Soc, IEPS, EIA, IEEE, CPMT Div DE MCM; packaging; reliability; modeling; analysis; thermo-mechanical C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY HYBRID MICROELECTRONICS PI RESTON PA MICROELECTRONIC SOC 1850 CENTENNIAL PARK DRIVE SUITE 105, RESTON, VA 22091 BN 0-930815-47-5 J9 P SOC PHOTO-OPT INS PY 1996 VL 2794 BP 193 EP 198 PG 6 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BF76X UT WOS:A1996BF76X00033 ER PT B AU Larson, TW Newell, JM Cornford, SL AF Larson, TW Newell, JM Cornford, SL GP INT SOC HYBRID MICROELECTR TI Thermo-mechanical analysis and fatigue life prediction of MCM-D interconnects SO 1966 INTERNATIONAL CONFERENCE ON MULTICHIP MODULES, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1996 International Conference on Multichip Modules CY APR 17-19, 1996 CL DENVER, CO SP Int Soc Hybrid Microelectr, Microelectr Soc, IEPS, EIA, IEEE, CPMT Div DE MCM; analysis; thermo-mechanical; reliability; fatigue C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY HYBRID MICROELECTRONICS PI RESTON PA MICROELECTRONIC SOC 1850 CENTENNIAL PARK DRIVE SUITE 105, RESTON, VA 22091 BN 0-930815-47-5 J9 P SOC PHOTO-OPT INS PY 1996 VL 2794 BP 317 EP 322 PG 6 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BF76X UT WOS:A1996BF76X00055 ER PT B AU Austin, RA Minamitani, T Ramsey, BD AF Austin, RA Minamitani, T Ramsey, BD BE Moonier, PA TI A hard x-ray imaging polarimeter for balloon-borne astronomy SO 1995 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE RECORD, VOLS 1-3 LA English DT Proceedings Paper CT 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference CY OCT 21-28, 1995 CL SAN FRANCISCO, CA SP IEEE C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3181-8 PY 1996 BP 131 EP 135 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BF95Z UT WOS:A1996BF95Z00030 ER PT B AU Soli, GA Garrett, HB Fossum, ER AF Soli, GA Garrett, HB Fossum, ER BE Moonier, PA TI CMOS charged particle spectrometers SO 1995 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE RECORD, VOLS 1-3 LA English DT Proceedings Paper CT 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference CY OCT 21-28, 1995 CL SAN FRANCISCO, CA SP IEEE C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3181-8 PY 1996 BP 229 EP 233 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BF95Z UT WOS:A1996BF95Z00052 ER PT B AU Cuddapah, R Bertsch, DL Catelli, JR Dingus, BL Esposito, JA Fichtel, CE Hartman, RC Hunter, SD Mukherjee, R Thompson, DJ Vogt, JM AF Cuddapah, R Bertsch, DL Catelli, JR Dingus, BL Esposito, JA Fichtel, CE Hartman, RC Hunter, SD Mukherjee, R Thompson, DJ Vogt, JM BE Moonier, PA TI Testing of large area drift chambers at the Saskatchewan accelerator laboratory for high energy astrophysics SO 1995 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE RECORD, VOLS 1-3 LA English DT Proceedings Paper CT 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference CY OCT 21-28, 1995 CL SAN FRANCISCO, CA SP IEEE C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3181-8 PY 1996 BP 248 EP 252 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BF95Z UT WOS:A1996BF95Z00056 ER PT B AU Bolotnikov, A Ramsey, B AF Bolotnikov, A Ramsey, B BE Moonier, PA TI Development of high-pressure Xe ionization detectors for hard X-ray and low energy gamma-ray astronomy SO 1995 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE RECORD, VOLS 1-3 LA English DT Proceedings Paper CT 1995 IEEE Nuclear Science Symposium and Medical Imaging Conference CY OCT 21-28, 1995 CL SAN FRANCISCO, CA SP IEEE C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3181-8 PY 1996 BP 258 EP 262 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Instruments & Instrumentation; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BF95Z UT WOS:A1996BF95Z00058 ER PT B AU Huang, ZC Mott, DB Shu, PK AF Huang, ZC Mott, DB Shu, PK GP IEEE TI Improvement of metal-semiconductor-metal GaN ultraviolet detectors SO 1996 54TH ANNUAL DEVICE RESEARCH CONFERENCE DIGEST LA English DT Proceedings Paper CT 54th Annual Device Research Conference CY JUN 24-26, 1996 CL SANTA BARBARA, CA SP IEEE, Electron Devices Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3358-6 PY 1996 BP 188 EP 189 DI 10.1109/DRC.1996.546430 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BG23Q UT WOS:A1996BG23Q00074 ER PT B AU Tunstel, E AkbarzadehT, MR Kumbla, K Jamshidi, M AF Tunstel, E AkbarzadehT, MR Kumbla, K Jamshidi, M BE Smith, MH Lee, MA Keller, J Yen, J TI Soft computing paradigms for learning fuzzy controllers with applications to robotics SO 1996 BIENNIAL CONFERENCE OF THE NORTH AMERICAN FUZZY INFORMATION PROCESSING SOCIETY - NAFIPS LA English DT Proceedings Paper CT 1996 Biennial Conference of the North-American-Fuzzy-Information-Processing-Society CY JUN 19-22, 1996 CL BERKELEY, CA SP N Amer Fuzzy Informat Proc Soc, Berkeley Initiat Soft Comp, IEEE, Neural Networks Council, IEEE, Syst Man & Cybernet Soc, Univ Calif, Berkeley C1 UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,NASA,CTR AUTONOMOUS CONTROL ENGN,ALBUQUERQUE,NM 87131. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3225-3 PY 1996 BP 355 EP 359 PG 5 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics SC Computer Science GA BF95N UT WOS:A1996BF95N00068 ER PT B AU Imbriale, WA Esquivel, MS AF Imbriale, WA Esquivel, MS GP IEEE TI A novel design technique for beam-waveguide antennas SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 111 EP 119 PG 9 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00006 ER PT B AU Manshadi, F AF Manshadi, F GP IEEE TI The S/X-band microwave feed system for NASA's first beamwaveguide antenna SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 121 EP 127 PG 7 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00007 ER PT B AU Chau, SN Reh, KR Cox, B Barfield, JN Lockhart, WL McLelland, ML AF Chau, SN Reh, KR Cox, B Barfield, JN Lockhart, WL McLelland, ML GP IEEE TI A multi-mission space avionics architecture SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 165 EP 176 PG 12 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00012 ER PT B AU Deutsch, LJ AF Deutsch, LJ GP IEEE TI A new Deep Space Network for the next century SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,TELECOMMUN & MISSION OPERAT,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 191 EP 204 PG 14 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00014 ER PT B AU Spear, AJ AF Spear, AJ GP IEEE TI Progress report on Mars Pathfinder Project approach SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 243 EP 261 PG 19 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00018 ER PT B AU White, AL Kim, H AF White, AL Kim, H GP IEEE TI Designing experiments for controller perturbation theories - An example SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 265 EP 278 PG 14 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00019 ER PT B AU Slonski, JP AF Slonski, JP GP IEEE IEEE IEEE IEEE TI System fault protection design for the Cassini spacecraft SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-3196-6 PY 1996 BP 279 EP 292 PG 14 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00020 ER PT B AU Kim, H White, AL Shin, KG AF Kim, H White, AL Shin, KG GP IEEE TI Susceptibility of controller computers to environmental disruptions and its effects on system stability SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 309 EP 320 PG 12 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00022 ER PT B AU LaBel, KA Gates, MM Moran, AK MArshall, PW Barth, J Stassinopoulos, EG Seidleck, CM Dale, CJ AF LaBel, KA Gates, MM Moran, AK MArshall, PW Barth, J Stassinopoulos, EG Seidleck, CM Dale, CJ GP IEEE TI Commercial microelectronics technologies for applications in the satellite radiation environment SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 375 EP 390 PG 16 WC Engineering, Aerospace; Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BF08Y UT WOS:A1996BF08Y00027 ER PT B AU Stuhr, F Jordan, R Werner, M AF Stuhr, F Jordan, R Werner, M GP IEEE TI SIR-C/X-SAR: An advanced radar SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 5 EP 16 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00001 ER PT B AU Plaut, JJ AF Plaut, JJ GP IEEE TI Summary of science results from spaceborne imaging radar (SIR-C/X-SAR) SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 19 EP 26 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00002 ER PT B AU Jones, TD Godwin, LM Wisoff, PJ Evans, CA Amsbury, DL AF Jones, TD Godwin, LM Wisoff, PJ Evans, CA Amsbury, DL GP IEEE TI Astronaut earth observations during the space radar laboratory missions SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,LYNDON B JOHNSON SPACE CTR,ASTRONAUT OFF,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 29 EP 46 PG 18 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00003 ER PT B AU Evans, DL Freeman, A AF Evans, DL Freeman, A GP IEEE TI Beyond SIR-C/X-SAR SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 49 EP 55 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00004 ER PT B AU Casani, EK AF Casani, EK GP IEEE TI The new millennium program: Management challenges in the 21st century SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 59 EP 64 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00005 ER PT B AU Eisenman, A Joergensen, JL Liebe, CC AF Eisenman, A Joergensen, JL Liebe, CC GP IEEE TI Real sky performance of the prototype Orsted advanced stellar compass SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,TRACKING SENSORS GRP,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 103 EP 113 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00010 ER PT B AU Everett, DF Sparr, LM AF Everett, DF Sparr, LM GP IEEE TI Wide-field infrared explorer spacecraft system design SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 145 EP 158 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00013 ER PT B AU Muirhead, BK AF Muirhead, BK GP IEEE TI Mars Pathfinder flight system design and implementation SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 159 EP 171 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00014 ER PT B AU Wright, MR AF Wright, MR GP IEEE TI Shuttle small payloads: How to fly shuttle in the ''faster, cheaper, better'' world SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 187 EP 195 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00016 ER PT B AU Burt, IJ AF Burt, IJ GP IEEE TI Transition region and coronal explorer mission SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 197 EP 212 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00017 ER PT B AU Smith, JL AF Smith, JL GP IEEE TI A revolution in robotic space exploration: Ten times as many missions at ten percent of the cost per mission SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 213 EP 226 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00018 ER PT B AU Morakis, JC Miller, WH AF Morakis, JC Miller, WH GP IEEE TI Bandwidth and modulation techniques under study by NASA SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 359 EP 366 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF08Z UT WOS:A1996BF08Z00029 ER PT B AU Sterling, T AF Sterling, T GP IEEE TI PetaFLOPS scale computing systems, opportunities, and challenges SO 1996 IEEE AEROSPACE APPLICATIONS CONFERENCE, PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1996 IEEE Aerospace Applications Conference CY FEB 03-10, 1996 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc C1 NASA,GODDARD SPACE FLIGHT CTR,CESDIS,USRA,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3196-6 PY 1996 BP 31 EP 49 PG 19 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BF09A UT WOS:A1996BF09A00002 ER PT S AU Sull, S Sridhar, B AF Sull, S Sridhar, B GP IEEE TI Runway obstacle detection by controlled spatiotemporal image flow disparity SO 1996 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS / CVPR, IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1966 IEEE Computer Society Conference on Computer Vision and Pattern Recognition CY JUN 18-20, 1996 CL SAN FRANCISCO, CA SP IEEE, Computer Soc, Tech Comm Pattern Anal & Machine Intelligence C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1063-6919 BN 0-8186-7258-7 J9 PROC CVPR IEEE PY 1996 BP 385 EP 390 DI 10.1109/CVPR.1996.517101 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BF92T UT WOS:A1996BF92T00057 ER PT S AU HelOr, Y Teo, PC AF HelOr, Y Teo, PC GP IEEE TI Canonical decomposition of steerable functions SO 1996 IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS SE PROCEEDINGS / CVPR, IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT 1966 IEEE Computer Society Conference on Computer Vision and Pattern Recognition CY JUN 18-20, 1996 CL SAN FRANCISCO, CA SP IEEE, Computer Soc, Tech Comm Pattern Anal & Machine Intelligence C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 5 Z9 6 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1063-6919 BN 0-8186-7258-7 J9 PROC CVPR IEEE PY 1996 BP 809 EP 816 DI 10.1109/CVPR.1996.517165 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BF92T UT WOS:A1996BF92T00121 ER PT B AU Chren, WA Wyman, BF AF Chren, WA Wyman, BF GP IEEE TI Digital oscillators over finite fields SO 1996 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, CONFERENCE PROCEEDINGS, VOLS 1-6 LA English DT Proceedings Paper CT 1996 IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP 96) CY MAY 07-10, 1996 CL ATLANTA, GA SP IEEE, Signal Proc Soc C1 GRAND VALLEY STATE UNIV,NASA,LEWIS RES CTR,ALLENDALE,MI 49401. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3192-3 J9 INT CONF ACOUST SPEE PY 1996 BP 3209 EP 3212 PG 4 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA BG26G UT WOS:A1996BG26G00809 ER PT B AU Johnson, MJ Townsend, JN AF Johnson, MJ Townsend, JN GP IEEE TI Achieving high throughput for data transfer over ATM networks SO 1996 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS - CONVERGING TECHNOLOGIES FOR TOMORROW'S APPLICATIONS, VOLS. 1-3 LA English DT Proceedings Paper CT 1996 IEEE International Conference on Communications - Converging Technologies for Tomorrows Applications (ICC 96) CY JUN 23-27, 1996 CL DALLAS, TX SP IEEE Commun Soc, IEEE, Dallas Sect C1 NASA,AMES RES CTR,RIACS,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3251-2 PY 1996 BP 405 EP 411 PG 7 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA BG05Y UT WOS:A1996BG05Y00075 ER PT B AU Simon, M Tsou, HP Hinedi, S Hamdan, K AF Simon, M Tsou, HP Hinedi, S Hamdan, K GP IEEE TI The performance of a coherent residual carrier PSK system using hybrid carrier phase synchronization SO 1996 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS - CONVERGING TECHNOLOGIES FOR TOMORROW'S APPLICATIONS, VOLS. 1-3 LA English DT Proceedings Paper CT 1996 IEEE International Conference on Communications - Converging Technologies for Tomorrows Applications (ICC 96) CY JUN 23-27, 1996 CL DALLAS, TX SP IEEE Commun Soc, IEEE, Dallas Sect C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3251-2 PY 1996 BP 1275 EP 1280 PG 6 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA BG05Y UT WOS:A1996BG05Y00238 ER PT S AU Backes, PG Peters, SF Phan, L Tso, KS AF Backes, PG Peters, SF Phan, L Tso, KS GP IEEE, ROBOT & AUTOMAT SOC TI Task lines and motion guides SO 1996 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1996 IEEE International Conference on Robotics and Automation CY APR 22-28, 1996 CL MINNEAPOLIS, MN SP IEEE, Robot & Automat Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. NR 0 TC 3 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-2989-9 J9 IEEE INT CONF ROBOT PY 1996 BP 50 EP 57 PG 8 WC Automation & Control Systems SC Automation & Control Systems GA BF68P UT WOS:A1996BF68P00009 ER PT S AU Li, L Cox, B Diftler, M Shelton, S Rogers, B AF Li, L Cox, B Diftler, M Shelton, S Rogers, B GP IEEE, ROBOT & AUTOMAT SOC TI Development of a telepresence controlled ambidextrous robot for space applications SO 1996 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1996 IEEE International Conference on Robotics and Automation CY APR 22-28, 1996 CL MINNEAPOLIS, MN SP IEEE, Robot & Automat Soc C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 7 Z9 7 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-2989-9 J9 IEEE INT CONF ROBOT PY 1996 BP 58 EP 63 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BF68P UT WOS:A1996BF68P00010 ER PT S AU Fiorini, P Shiller, Z AF Fiorini, P Shiller, Z GP IEEE, ROBOT & AUTOMAT SOC TI Time optimal trajectory planning in dynamic environments SO 1996 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1996 IEEE International Conference on Robotics and Automation CY APR 22-28, 1996 CL MINNEAPOLIS, MN SP IEEE, Robot & Automat Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 20 Z9 20 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-2989-9 J9 IEEE INT CONF ROBOT PY 1996 BP 1553 EP 1558 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BF68P UT WOS:A1996BF68P00243 ER PT S AU Bon, B Seraji, H AF Bon, B Seraji, H GP IEEE, ROBOT & AUTOMAT SOC TI On-line collision avoidance for the ranger telerobotic flight experiment SO 1996 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1996 IEEE International Conference on Robotics and Automation CY APR 22-28, 1996 CL MINNEAPOLIS, MN SP IEEE, Robot & Automat Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 6 Z9 6 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-2989-9 J9 IEEE INT CONF ROBOT PY 1996 BP 2041 EP 2048 PG 8 WC Automation & Control Systems SC Automation & Control Systems GA BF68P UT WOS:A1996BF68P00320 ER PT S AU Fiorini, P Seraji, H Long, M AF Fiorini, P Seraji, H Long, M GP IEEE, ROBOT & AUTOMAT SOC TI A PC-based configuration controller for dexterous 7-DOF arms SO 1996 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1996 IEEE International Conference on Robotics and Automation CY APR 22-28, 1996 CL MINNEAPOLIS, MN SP IEEE, Robot & Automat Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-2989-9 J9 IEEE INT CONF ROBOT PY 1996 BP 3689 EP 3694 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BF68P UT WOS:A1996BF68P00579 ER PT S AU Panicacci, RA Kemeny, SE Jones, PD Staller, C Fossum, ER AF Panicacci, RA Kemeny, SE Jones, PD Staller, C Fossum, ER BE Wuorinen, JH TI 128Mb/s multiport CMOS binary active-pixel image sensor SO 1996 IEEE INTERNATIONAL SOLID-STATE CIRCUITS CONFERENCE, DIGEST OF TECHNICAL PAPERS SE ISSCC DIGEST OF TECHNICAL PAPERS LA English DT Proceedings Paper CT 1996 IEEE International Solid-State Circuits Conference CY FEB 08-10, 1996 CL SAN FRANCISCO, CA SP IEEE, Solid State Circuits Council, IEEE, San Francisco Sect, Bay Area Council, Univ Penn C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0193-6530 BN 0-7803-3137-0 J9 ISSCC DIG TECH PAP I PY 1996 VL 39 BP 100 EP 101 DI 10.1109/ISSCC.1996.488531 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BF43W UT WOS:A1996BF43W00034 ER PT B AU Huang, J AF Huang, J GP IEEE BOSTON SECT TI Capabilities of printed reflectarray antennas SO 1996 IEEE INTERNATIONAL SYMPOSIUM ON PHASED ARRAY SYSTEMS AND TECHNOLOGY: REVOLUTIONARY DEVELOPMENTS IN PHASED ARRAYS LA English DT Proceedings Paper CT 1996 IEEE International Symposium on Phased Array Systems and Technology - Revolutionary Developments in Phased Arrays CY OCT 15-18, 1996 CL BOSTON, MA SP IEEE Boston Sect, IEEE Aerosp & Electr Syst Soc, IEEE Commun Soc, IEEE Antennas & Propagat Soc, IEEE Microwave Theory & Tech Soc AB This article presents an advanced antenna technology, namely the printed reflectarray, that has the potential for providing an enhanced communication capability with relatively low cost, small size and small mass. It has application in the commercial and military arenas as well as in space exploration. RP Huang, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3232-6 PY 1996 BP 131 EP 134 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BG87R UT WOS:A1996BG87R00027 ER PT S AU Mehdi, I Lee, TH Humphrey, DA Martin, SC Dengler, RJ Oswald, JE Pease, A Smith, RP Siegel, PH AF Mehdi, I Lee, TH Humphrey, DA Martin, SC Dengler, RJ Oswald, JE Pease, A Smith, RP Siegel, PH BE Ranson, RG Pollard, RD TI 600 GHz planar-Schottky-diode subharmonic waveguide mixers SO 1996 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT 1996 IEEE MTT-S International Microwave Symposium CY JUN 17-21, 1996 CL SAN FRANCISCO, CA SP IEEE, MTT Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 3 Z9 3 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-645X BN 0-7803-3247-4 J9 IEEE MTT-S PY 1996 BP 377 EP 380 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BF95U UT WOS:A1996BF95U00086 ER PT S AU Lee, TH Humphrey, DA Dengler, RJ Mehdi, I Martin, SC Pease, A Oswald, JE Smith, RP Siegel, PH AF Lee, TH Humphrey, DA Dengler, RJ Mehdi, I Martin, SC Pease, A Oswald, JE Smith, RP Siegel, PH BE Ranson, RG Pollard, RD TI Fabrication and performance of separately-biasable antiparallel-pair ''T-anode'' mixer diodes employing a compact multiple-layer integrated bias circuit at 210 GHz SO 1996 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT 1996 IEEE MTT-S International Microwave Symposium CY JUN 17-21, 1996 CL SAN FRANCISCO, CA SP IEEE, MTT Soc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-645X BN 0-7803-3247-4 J9 IEEE MTT-S PY 1996 BP 381 EP 384 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BF95U UT WOS:A1996BF95U00087 ER PT S AU Shalkhauser, KA Windyka, JA Dening, DC Fithian, MJ AF Shalkhauser, KA Windyka, JA Dening, DC Fithian, MJ BE Ranson, RG Pollard, RD TI System-level integrated circuits for phased array antenna applications SO 1996 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT 1996 IEEE MTT-S International Microwave Symposium CY JUN 17-21, 1996 CL SAN FRANCISCO, CA SP IEEE, MTT Soc C1 NASA,CLEVELAND,OH. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-645X BN 0-7803-3247-4 J9 IEEE MTT-S PY 1996 BP 1593 EP 1596 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BF95U UT WOS:A1996BF95U00371 ER PT B AU Bolotin, G AF Bolotin, G GP IEEE TI Space-Cube: A flexible computer architecture based on stacked modules SO 1996 IEEE MULTI-CHIP MODULE CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 1996 IEEE Multi-Chip Module Conference CY FEB 06-07, 1996 CL SANTA CRUZ, CA SP IEEE Circuits & Syst Soc, IEEE Components Packaging & Mfg Technol Soc, IEEE Electron Devices Soc, IEEE Comp Soc, IEEE Comp Soc Tech Comm VLSI C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7286-2 PY 1996 BP 20 EP 25 DI 10.1109/MCMC.1996.510763 PG 6 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BF12Y UT WOS:A1996BF12Y00005 ER PT B AU Sharma, AK Sahu, K Brashears, S AF Sharma, AK Sahu, K Brashears, S GP IEEE TI Total ionizing dose (TID) evaluation results of low dose rate testing for NASA programs SO 1996 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1996 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC 96) CY JUL 19, 1996 CL INDIAN WELLS, CA SP IEEE Nucl & Plasma Sci Soc AB Low dose rate radiation testing in the range of 0.01-0.20 rads(Si)/s has been performed at Goddard Space Flight Center on a wide variety of non-RH (rad-hard) part types in the last few years [1,2]. This paper reports on recent test results of EEPROMs, Operational Amplifiers, Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs), and DC-DC converters. These results have shown that non-RH parts are suitable for many low earth orbiting satellites, where predicted mission total dose requirements may be in the range of 0.5-10 krads(Si). However, a careful characterization of non-RH parts should be performed to verify that the parts meet the requirements of their intended application in the projected mission radiation environment. RP Sharma, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 1 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3398-5 PY 1996 BP 13 EP 18 DI 10.1109/REDW.1996.574183 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BH34G UT WOS:A1996BH34G00003 ER PT B AU LaBel, KA Moran, AK Hawkins, DK Sanders, AB Seidleck, CM Kim, HS Forney, JE Stassinopoulos, EG Marshall, P Dale, C Kinnison, J Carkhuff, B AF LaBel, KA Moran, AK Hawkins, DK Sanders, AB Seidleck, CM Kim, HS Forney, JE Stassinopoulos, EG Marshall, P Dale, C Kinnison, J Carkhuff, B GP IEEE TI Current single event effect test results for candidate spacecraft electronics SO 1996 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1996 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC 96) CY JUL 19, 1996 CL INDIAN WELLS, CA SP IEEE Nucl & Plasma Sci Soc AB We present both proton and heavy ion single event effect (SEE) ground test results for candidate spacecraft electronics. A variety of digital and analog devices were tested, including EEPROMs, DRAMs, and DC-DC Converters. RP LaBel, KA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 735-1,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3398-5 PY 1996 BP 19 EP 27 DI 10.1109/REDW.1996.574184 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BH34G UT WOS:A1996BH34G00004 ER PT B AU Nichols, DK Coss, JR Miyahira, T Titus, J Oberg, D Wert, J Majewski, P Lintz, J AF Nichols, DK Coss, JR Miyahira, T Titus, J Oberg, D Wert, J Majewski, P Lintz, J GP IEEE TI Update of single event failure in power MOSFETs SO 1996 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1996 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC 96) CY JUL 19, 1996 CL INDIAN WELLS, CA SP IEEE Nucl & Plasma Sci Soc AB This paper presents an update of the first 1994 compendium of single event test data for power MOSFETs. It provides failure thresholds from burnout or gate rupture for 61 devices of six manufacturers. RP Nichols, DK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3398-5 PY 1996 BP 67 EP 72 DI 10.1109/REDW.1996.574191 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BH34G UT WOS:A1996BH34G00011 ER PT B AU Buehler, MG Cheng, LJ Martin, DP AF Buehler, MG Cheng, LJ Martin, DP GP IEEE TI Test structures for rapid prototyping of gas and pressure sensors SO 1996 INTERNATIONAL INTEGRATED RELIABILITY WORKSHOP FINAL REPORT LA English DT Proceedings Paper CT 1996 Integrated Reliability Workshop CY OCT 20-23, 1996 CL STANFORD SIERRA CAMP, LAKE TAHOE, CA SP IEEE Electron Devices Soc, IEEE Reliabil Soc HO STANFORD SIERRA CAMP AB A multi-project ceramic substrate was used in developing a gas sensor and pressure sensor. The ceramic substrate contained 36 chips with six variants including sensors, process control monitors, and an interconnect chip. The gas sensor is being developed as an air quality monitor and the pressure gauge as a Martian barometer. This effort was directed at mitigating reliability problems by proper material and circuit choices. RP Buehler, MG (reprint author), CALTECH,JET PROP LAB,MICRODEVICES LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3598-8 PY 1996 BP 72 EP 76 DI 10.1109/IRWS.1996.583387 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA BH55V UT WOS:A1996BH55V00012 ER PT B AU Ponchak, GE Robertson, S Brauchler, F East, J Katehi, LPB AF Ponchak, GE Robertson, S Brauchler, F East, J Katehi, LPB GP SOC PHOTO OPT INSTRUMENTAT ENGINEERS TI Finite width coplanar waveguide for microwave and millimeter-wave integrated circuits SO 1996 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1996 International Symposium on Microelectronics CY OCT 08-10, 1996 CL MINNEAPOLIS, MN SP ISHM, Microelectr Soc, Soc Photo Opt Instrumentat Engineers DE microwave; millimeter-wave; transmission lines; coplanar waveguide C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-930815-48-3 J9 P SOC PHOTO-OPT INS PY 1996 VL 2920 BP 517 EP 521 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA BG45G UT WOS:A1996BG45G00086 ER PT B AU Ma, KL VanRosendale, J Vermeer, W AF Ma, KL VanRosendale, J Vermeer, W GP ASSOC COMP MACHINERY TI 3D shock wave visualization on unstructured grids SO 1996 SYMPOSIUM ON VOLUME VISUALIZATION, PROCEEDINGS LA English DT Proceedings Paper CT 1996 Symposium on Volume Visualization CY OCT 28-29, 1996 CL SAN FRANCISCO, CA SP ACM SIGGRAPH, IEEE Comp Soc Tech Comm Comp Graph AB A critical issue in understanding high speed flows is the study of shock waves. This paper summarizes our research on techniques for the detection and visualization of shock waves occuring in simulations of three-dimensional flows on unstructured grids. Detection algorithms based on Mach number, density gradient and directional derivatives are compared using a data set from calculations of a transonic flow with a weak double shock around an airfoil. Both surface and volume rendering techniques are used to display the shocks. The issues in this research area are very much like those occurring in medical imaging. Since the data themselves (in this case the results of the fluid dynamics simulation) are intrinsically low resolution and noisy, properly extracting and visualizing the shock is very difficult. In this environment blurry, low-resolution techniques, like the splatting volume rendering, seem to do rather well. More complex schemes, using sophisticated numerical shock detectors coupled with polygon rendering, produce visually sharper shocks, but also introduce ''graphics artifacts,'' which complicate understanding of the flow physics. On the other hand, visualization results produced with techniques like splatting are, in effect, relying more on the human visual system to compensate for limited resolution in the simulation. RP Ma, KL (reprint author), NASA,LANGLEY RES CTR,INST COMP APPL SCI & ENGN,HAMPTON,VA 23681, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 BN 0-89791-865-7 PY 1996 BP 87 EP 94 DI 10.1109/SVV.1996.558049 PG 8 WC Computer Science, Software Engineering SC Computer Science GA BG69J UT WOS:A1996BG69J00011 ER PT J AU Miller, MK AF Miller, MK GP NASA TI Reduction of calcofluor in solithane conformal coatings of printed wiring boards SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB An investigation on the outgassing of a pigment employed as a fluorescent medium in conformal coatings has been performed. The conformal coatings in question are used to protect printed wiring boards from environmental hazards such as dust and moisture. The pigment is included in the coating at low concentration to allow visual inspection of the conformal coating for flaw detection. Calcofluor, the fluorescent pigment has been found to be a significant outgasser under vacuum conditions and a potential source of contamination to flight hardware. A minimum acceptable concentration of Calcofluor for flaw detection is desirable. Tests have been carried out using a series of Solithane(TM) conformal coating samples, with progressively lower Calcofluor concentrations, to determine the minimum required concentration of Calcofluor. It was found that the concentration of Calcofluor could be reduced from 0.115% to 0.0135% without significant loss in the ability to detect flaws, while at the same time significant reductions in Calcofluor outgassing and possible contamination of systems could be realized. RP Miller, MK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 37 EP 43 PG 7 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00005 ER PT J AU Johnson, KR AF Johnson, KR GP NASA TI Mars Pathfinder Spacecraft, lander, and rover testing in simulated deep space and Mars surface environments SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB The Mars Pathfinder (MPF) Spacecraft was built and tested at the Jet Propulsion Laboratory during 1995/96. MPF is scheduled to launch in December 1996 and to land on Mars on July 4, 1997. The testing program for MPF required subjecting the mission hardware to both deep space and Mars surface conditions. A series of tests were devised and conducted from 1/95 to 7/96 to study the thermal response of the MPF spacecraft to the environmental conditions in which it will be exposed during the cruise phase (on the way to Mars) and the lander phase (landed on Mars) of the mission. Also, several tests were conducted to study the thermal characteristics of the Mars rover, Sojourner, under Mars surface environmental conditions. For these tests, several special test fixtures and methods were devised to simulate the required environmental conditions. Creating simulated Mars surface conditions was a challenging undertaking since Mars' surface is subjected to diurnal cycling between -20 degrees C and -85 degrees C, with windspeeds to 20 m/sec, occurring in an 8 torr CO2 atmosphere. This paper describes the MPF test program which was conducted at JPL to verify the MPF thermal design. RP Johnson, KR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 57 EP 76 PG 20 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00007 ER PT J AU Dunn, JL AF Dunn, JL GP NASA TI SWAS spacecraft T/V test, unique in chamber tests systems actuation SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB The Sub-Millimeter Wave Astronomy Satellite (SWAS) is the third mission of the Small Explorer (SMEX) Project at Goddard Space Flight Center (GSFC). It is a path finding mission to study the chemical composition of interstellar galactic clouds to help determine the process of star formation. The spacecraft recently completed a month-long thermal vacuum/thermal balance test in the Solar Environmental Simulator, the largest thermal vacuum facility at Goddard. Rather extensive fu;turing was required for the test, considering the small size of the spacecraft, and two unusual deployments were completed in order to accomplish the goals of the test. This paper discusses the space simulation testing of the fully integrated SWAS spacecraft and the unique fixturing required. RP Dunn, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 77 EP 79 PG 3 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00008 ER PT J AU Mattiello, CF AF Mattiello, CF GP NASA TI Acceleration testing - A better, faster, cheaper alternative for strength qualification testing SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB This paper addresses the advantages of utilizing a centrifuge test over the conventional static load test methods to structurally qualify aerospace structures. Three recent test cases are reviewed and used as examples to highlight these benefits. In addition, the overall capability of Goddard's High Capacity Centrifuge (HCC) is outlined along with some unique features that were designed specifically to reduce costs, test turn around time, and increase test item safety. RP Mattiello, CF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ENVIRONM TEST & INTEGRAT BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 117 EP 125 PG 9 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00014 ER PT J AU Worth, DB AF Worth, DB GP NASA TI A method for implementing force-limited vibration control SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB NASA/GSFC has implemented force-limited vibration control on a controller which can only accept one profile. The method uses a personal computer based digital signal processing board to convert force and/or moment signals into what appears to be an acceleration signal to the controller. This technique allows test centers with older controllers to use the latest force-limited control techniques for random vibration testing. The paper describes the method, hardware, and test procedures used. An example from a test performed at NASA/GSFC is used as a guide. RP Worth, DB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 127 EP 139 PG 13 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00015 ER PT B AU Mitchell, DR AF Mitchell, DR GP NASA TI Magnetic test performance capabilities at the Goddard Space Flight Center as applied to the global geospace science initiative SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB Goddard Space Flight Center's (GSFC) Spacecraft Magnetic Test Facility (SMTF) is a historic test facility that has set the standard for all subsequent magnetic test facilities. The SMTF was constructed in the early 1960's for the purpose of simulating geomagnetic and interplanetary magnetic fields. Additionally, the facility provides the capability for measuring spacecraft generated magnetic fields as well as calibrating magnetic attitude control systems and science magnetometers. The SMTF was designed for large, spacecraft level tests and is currently the second largest spherical coil system in the world. The SMTF is a three-axis Braunbek system composed of four coils on each of three orthogonal axes. The largest coils are 12.7 meters (41.6 feet) in diameter. The three-axis Braunbek configuration provides a highly uniform cancellation of the geomagnetic field over the central 1.8 meter (6 foot) diameter primary test volume. Cancellation of the local geomagnetic field is to within +/-0.2 nano Tesla with a uniformity of up to 0.001% within the 1.8 meter (6 foot) diameter primary test volume. Artificial magnetic field vectors from 0-60,000 nano Tesla can be generated along any axis with a 0.1 nano Tesla resolution. Oscillating or rotating field vectors can also be produced about any axis with a frequency of up to 100 radians/second. Since becoming fully operational in July of 1967, the SMTF has been the site of numerous spacecraft magnetics tests. Spacecraft tested at the SMTF include : the Solar Maximum Mission (SMM), Magsat, LANDSAT-D, the Fast Auroral Snapshot (FAST) Explorer and the Sub-millimeter-Wave-Astronomy Satellite (SWAS) among others. This paper describes the methodology and sequencing used for the Global Geospace Science (GGS) initiative magnetic testing program in the Goddard Space Flight Center's SMTF. The GGS initiative provides an exemplary model of a strict and comprehensive magnetic control program. RP Mitchell, DR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ENGN SERV DIV,ENVIRONM TEST ENGN & INTEGRAT BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 205 EP 216 PG 12 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00023 ER PT J AU Townsend, JA AF Townsend, JA GP NASA TI A comparison of atomic oxygen degradation in low earth orbit and in a plasma etcher SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB In low Earth orbit (LEG) significant degradation of certain materials occurs from exposure to atomic oxygen(AO). Orbital opportunities to study this degradation for specific materials are limited and expensive. While plasma etchers are commonly used in ground-based studies because of their low cost and convenience, the environment produced in an etcher chamber differs greatly from the LEO environment. Because of the differences in environment, the validity of using etcher data has remained an open question. In this paper, degradation data for 22 materials from the orbital experiment Evaluation of Oxygen Interaction with Materials (EOIM-III) are compared with data from EOIM-III control specimens exposed in a typical plasma etcher. This comparison indicates that, when carefully considered, plasma etcher results can produce order-of-magnitude estimates of orbital degradation. This allows the etcher to be used to screen unacceptable materials from further, more expensive tests. RP Townsend, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAT ENGN BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 249 EP 258 PG 10 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00027 ER PT J AU Johnson, KR Levi, AG AF Johnson, KR Levi, AG GP NASA TI Graphic three-axes presentation of residual gas analyzer data SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB Residual gas analyzers (RGA) are commonly used to measure the composition of residual gases in thermal-vacuum test chambers. Measurements from RGA's are often used to identify and quantify outgassing contaminants from a test article during thermal-vacuum testing. RGA data is typically displayed as snapshots in time, showing instantaneous concentrations of ions from ionized residual gas molecules at different atomic masses. This ion concentration information can be interpreted to be representative of the composition of the residual gas in the chamber at the instant of analysis. Typically, test personnel are most interested in tracking the time history of changes in the composition of chamber residual gas to determine the relative cleanliness and the clean-up rate of the test article under vacuum. However, displays of instantaneous RGA data cannot provide test personnel with the preferred time history information. In order to gain an understanding of gas composition trends, a series of plots of individual data snapshots must be analyzed. This analysis is cumbersome and still does not provide a very satisfactory view of residual gas composition trends. A method was devised by the authors to present RGA data in a three-axis format, plotting Atomic Mass Unit (AMU), the Ionization Signal Response (ISR) as amps/torr as a function of AMU, and Time, to provide a clear graphic visualization of trends of changes in ISR with respect to time and AMU (representative of residual gas composition). This graphic visualization method provides a valuable analytical tool to interpret test article outgassing rates during thermal vacuum tests. Raw RGA data was extracted from a series of delimited ASCII files and then converted to a data array in a spreadsheet. Consequently, using the 3-D plotting functionality provided by the spreadsheet program, 3-D plots were produced. After devising the data format conversion process, the authors began developing a program to provide real-time 3-D plotting of RGA data. The intent of this program is to automate the RGA data acquisition process and to generate up-to-the-minute time history 3-D displays of stored RGA data (development of this program was not complete at the time of this writing). This paper provides a brief description of the data format conversion process and presents results from a recent test to illustrate the usefulness of this 3-D RGA data plotting technique. RP Johnson, KR (reprint author), CALTECH,JET PROPULS LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 291 EP 297 PG 7 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00032 ER PT J AU Webb, AT Sushon, J McCrary, L AF Webb, AT Sushon, J McCrary, L GP NASA TI Upgrade of a 10-foot diameter by 15-foot long thermal vacuum chamber SO 19TH SPACE SIMULATION CONFERENCE: COST EFFECTIVE TESTING FOR THE 21ST CENTURY SE NASA CONFERENCE PUBLICATION LA English DT Proceedings Paper CT 19th Space Simulation Conference - Cost Effective Testing for the 21st-Century CY OCT 28-31, 1996 CL BALTIMORE, MD SP NASA, Inst Environm Sci, Amer Inst Aeronaut & Astron, Amer Soc Testing & Mat, Canadian Space Agcy AB An extensive upgrade to a 10-foot diameter by 15-long thermal vacuum chamber located at Goddard Space Flight Center (GSFC) commenced in the fall of 1992 and was completed in the summer of 1995. The facility was completely dismantled removing three 35-inch diffusion pumps, other vacuum system components, the 200 horsepower thermal system blower, thermal shrouds, and all interconnecting piping. The intent of the upgrade was to replace the diffusion pumps with clean pumping and backfill systems, to install a new, efficient thermal system and shrouds, and to place the entire control system on a programmable logic controller. Many enhancements were made in the vacuum and thermal systems with provisions made into the design and the programming to provide the capability for any future automation task. The entire vacuum system was designed and integrated using in-house personnel on a non-interfering basis to other flight related tasks. The thermal system was a competitively bid ''turn-key'' system. Preparation of a thorough specification, pre-bid conferences with vendors, and good communications with the turn-key contractor resulted in an efficient, flexible, and uniform thermal system. The control system, based on a distributed I/O programmable logic controller (PLC) system, was developed, installed, and programmed by in-house personnel for both the vacuum and the thermal systems. Application of several different cleaning techniques, attention to cleanliness, pre-cured optical paint, and ability to operate the thermal system at 150 degrees C resulted in the facility exceeding the GSFC contamination requirements by a factor of 10 within several days of bakeout and virtually eliminated any background contamination from the old diffusion pumps. RP Webb, AT (reprint author), GODDARD SPACE FLIGHT CTR,MANTECH,NSI,TECHNOL SERV CORP,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NASA PI WASHINGTON PA WASHINGTON, DC 20546 J9 NASA CONF P PY 1996 VL 3341 BP 309 EP 321 PG 13 WC Engineering, Aerospace SC Engineering GA BG87U UT WOS:A1996BG87U00035 ER PT B AU Sellers, P Hall, F Margolis, H Kelly, B Baldocchi, D denHartog, G Cihlar, J Ryan, MG Goodison, B Crill, P Ranson, KJ Lettenmaier, D Wickland, DE AF Sellers, P Hall, F Margolis, H Kelly, B Baldocchi, D denHartog, G Cihlar, J Ryan, MG Goodison, B Crill, P Ranson, KJ Lettenmaier, D Wickland, DE GP AMER METEOROL SOC TI The Boreal Ecosystem-Atmosphere Study (BOREAS): An overview and early results. SO 22ND CONFERENCE ON AGRICULTURAL & FOREST METEOROLOGY WITH SYMPOSIUM ON FIRE & FOREST METEOROLOGY/12TH CONFERENCE ON BIOMETEOROLOGY & AEROBIOLOGY LA English DT Proceedings Paper CT 22nd Conference on Agricultural and Forest Meteorology with Symposium on Fire and Forest Meteorology/12th Conference on Biometeorology and Aerobiology CY JAN 28-FEB 02, 1996 CL ATLANTA, GA SP Amer Meteorol Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Ranson, Kenneth/G-2446-2012; Ryan, Michael/A-9805-2008 OI Ranson, Kenneth/0000-0003-3806-7270; Ryan, Michael/0000-0002-2500-6738 NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1996 BP 1 EP 4 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BF44H UT WOS:A1996BF44H00001 ER PT S AU Rockstad, HK Kenny, TW Kelly, PJ Gabrielson, TB AF Rockstad, HK Kenny, TW Kelly, PJ Gabrielson, TB BE Berliner, MJ Lindberg, JF TI A microfabricated electron-tunneling accelerometer as a directional underwater acoustic sensor SO ACOUSTIC PARTICLE VELOCITY SENSORS: DESIGN, PERFORMANCE, AND APPLICATIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Acoustic Particle Velocity Sensors - Design, Performance, and Applications CY SEP, 1995 CL MYSTIC, CT SP Naval Undersea Warfare Ctr Div Newport, USN, Off Naval Res, Acoust Soc Amer C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECT,PASADENA,CA 91109. NR 0 TC 2 Z9 4 U1 0 U2 3 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-549-6 J9 AIP CONF PROC PY 1996 IS 368 BP 57 EP 68 PG 12 WC Acoustics; Instruments & Instrumentation SC Acoustics; Instruments & Instrumentation GA BF36A UT WOS:A1996BF36A00004 ER PT B AU Zimbelman, D Burt, J Bruner, M Tarbell, T Edwards, C Chen, JR AF Zimbelman, D Burt, J Bruner, M Tarbell, T Edwards, C Chen, JR BE Masten, MK Stockum, LA TI Precision pointing and image stabilization for the transition region and coronal explorer solar observatory SO ACQUISITION, TRACKING, AND POINTING X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Acquisition, Tracking, and Pointing X Conference CY APR 10-11, 1996 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE spacecraft control systems; image stabilization systems; solar observatories C1 GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2120-0 J9 P SOC PHOTO-OPT INS PY 1996 VL 2739 BP 77 EP 88 DI 10.1117/12.241944 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BF87E UT WOS:A1996BF87E00007 ER PT B AU McGarry, JF Degnan, JJ Titterton, P Sweeney, H Conklin, BP Dunn, PJ AF McGarry, JF Degnan, JJ Titterton, P Sweeney, H Conklin, BP Dunn, PJ BE Masten, MK Stockum, LA TI Automated tracking for advanced satellite laser ranging systems SO ACQUISITION, TRACKING, AND POINTING X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Acquisition, Tracking, and Pointing X Conference CY APR 10-11, 1996 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE satellite laser ranging; autotracking; acquisition; correlation detection C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI McGarry, Jan/C-4109-2013 NR 0 TC 6 Z9 6 U1 1 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2120-0 J9 P SOC PHOTO-OPT INS PY 1996 VL 2739 BP 89 EP 103 DI 10.1117/12.241945 PG 15 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BF87E UT WOS:A1996BF87E00008 ER PT J AU Ishihara, A Ohira, Y Roy, RR Nagaoka, S Sekiguchi, C Hinds, WE Edgerton, VR AF Ishihara, A Ohira, Y Roy, RR Nagaoka, S Sekiguchi, C Hinds, WE Edgerton, VR TI Influence of spaceflight on succinate dehydrogenase activity and soma size of rat ventral horn neurons SO ACTA ANATOMICA LA English DT Article DE microgravity; neuronal oxidative potential; quantitative histochemistry; spinal cord plasticity; soma cross-sectional area; motoneurons; rat ID OXIDATIVE ENZYME-ACTIVITY; TIBIALIS ANTERIOR; SPINAL-CORD; MOTONEURONS; SUSPENSION AB Succinate dehydrogenase (SDH) activities and soma cross-sectional areas (CSA) of neurons in the dorsolateral region of the ventral horn at the L5 segmental level of the spinal cord in the rat were determined after 14 days of spaceflight and after 9 days of recovery on earth. The results were compared to those in age-matched ground-based control rats. Spinal cords were quick-frozen, and the SDH activity and CSA of a sample of neurons with a visible nucleus were determined using a digitizer and a computer-assisted image analysis system. An inverse relationship between CSA and SDH activity of neurons was observed in all groups of rats. No change in mean CSA or mean SDH activity or in the size distribution of neurons was observed following spaceflight or recovery. However, there was a selective decrease in the SDH activity of neurons with soma CSA between 500 and 800 mu m(2) in the flight rats, and this effect persisted for at least 9 days following return to 1 g. It remains to be determined whether the selected population of motoneurons or the specific motor pools affected by spaceflight may be restricted to specific muscles. C1 UNIV CALIF LOS ANGELES,SCH MED,HLTH SCI CTR,BRAIN RES INST,LOS ANGELES,CA 90095. UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI,LOS ANGELES,CA 90095. KYOTO UNIV,NEUROCHEM LAB,FAC INTEGRATED HUMAN STUDIES,KYOTO 606,JAPAN. NATL INST FITNESS & SPORTS,DEPT PHYSIOL & BIOMECH,KANOYA,JAPAN. NATL SPACE DEV AGCY JAPAN,SPACE EXPT GRP,TSUKUBA,IBARAKI,JAPAN. NASA,AMES RES CTR,PAYLOADS CTR,MOFFETT FIELD,CA 94035. NR 22 TC 27 Z9 30 U1 0 U2 2 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 0001-5180 J9 ACTA ANAT JI Acta Anat. PY 1996 VL 157 IS 4 BP 303 EP 308 PG 6 WC Anatomy & Morphology SC Anatomy & Morphology GA XN467 UT WOS:A1996XN46700004 PM 9259879 ER PT B AU Chave, RG Wiseman, TAJ Barmatz, MB Hahn, I AF Chave, RG Wiseman, TAJ Barmatz, MB Hahn, I BE Hatheway, AE TI A facility for interferometric measurement of linear displacement in actuators and calibration of sensors at cryogenic temperatures between 4.2 K and 77 K SO ACTUATOR TECHNOLOGY AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Actuator Technology and Applications CY AUG 07-08, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers DE actuators; magnetostriction; interferometry; cryogenic; low temperature gauging; gage calibration AB Recent advances in material science have lead to the development of new, very low temperature actuators of Terbium and Dysprosium with hitherto unavailable stroke, energy efficiency and force. The test instrument described here was developed to investigate the performance characteristics of these new materials and the devices based upon them. The instrument, referred to as a cryogenic dilatometer, is designed for measuring linear displacements, at accuracies of 0.1 micron, in a material, actuator or sensor operating at low temperatures including that of liquid helium. The instrument, just completed, maintains the sample ar a known temperature between 4.2 K and 77 K, subjects the actuator material to a known and variable magnetic field of up to 1,500 gauss, places a specific and variable preload of 750 N maximum against the actuator or sample, and measures the resulting actuator displacement. A secondary capability is to provide a reference measurement for calibrating commercial capacitance, eddy current, linear variable differential transformers and other displacement gages at low temperatures. The primary linear displacement measurement tool is a fringe counting interferometer. A liquid helium cooled probe provides the sample test environment. RP Chave, RG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2253-3 J9 P SOC PHOTO-OPT INS PY 1996 VL 2865 BP 58 EP 65 DI 10.1117/12.259028 PG 8 WC Optics SC Optics GA BG84M UT WOS:A1996BG84M00009 ER PT B AU Loeffler, CE AF Loeffler, CE BE Terashima, N Altman, E TI Artificial life of agents SO ADVANCED IT TOOLS LA English DT Proceedings Paper CT IFIP World Conference on IT Tools CY SEP 02-06, 1996 CL CANBERRA, AUSTRALIA SP Int Federat Informat Proc AB The research in virtual reality initiated by Carl Eugene Loeffler Research Director at SIMLAB, NASA/Robotics Engineering Consortium, Carnegie Mellon University, investigates existence within networked simulation environments. To date research efforts have been conducted in the area of tele-existence, where multiple users share or co-inhabit a common distributed space. As the research progresses, the environments have become populated by agents of varied classes: people, animals, objects, which are assigned prescribed behaviors as varied as themselves. New research directions study the nature of agents, and their emergence into the classification of life forms. Artificial life, or A-Life when assigned to agents, is the investigation of agents as actual living organisms in silico that possess the properties of living organisms in vitro. They are for all intent and purposes alive. This paper describes general direction in the growing field of agent research, and the current research conducted at SIMLAB in the area of the artificial life of agents. RP Loeffler, CE (reprint author), CARNEGIE MELLON UNIV,NASA,ROBOT ENGN CONSORTIUM,PITTSBURGH,PA 15213, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CHAPMAN & HALL PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN BN 0-412-75560-2 PY 1996 BP 48 EP 55 PG 8 WC Computer Science, Information Systems SC Computer Science GA BG90N UT WOS:A1996BG90N00006 ER PT B AU Generie, P Hayden, B AF Generie, P Hayden, B BE Ealey, MA TI Estimation of the on-orbit distortion of the Mars Orbiter Laser Altimeter (MOLA II) primary mirror SO ADVANCED MATERIALS FOR OPTICS AND PRECISION STRUCTURES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Materials for Optics and Precision Structures CY AUG 08, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers DE mirror distortion; beryllium mirror; micrometeoroid damage AB This paper describes the analyses performed to estimate the on-orbit distortion of the Mars Orbiter Laser Altimeter (MOLA II) primary mirror. MOLA II is one of five scientific instruments that will be flown on the Mars Global Surveyor. The MOLA II instrument will map the surface profile of Mars for a full Martian year to a resolution of 2 meters (local) vertical and 160 meters horizontal. The MOLA II telescope is an f/6 Cassegrain telescope with a 0.85 milliradian (mrad) field of view. The telescope is made entirely of Brush Wellman S200F vacuum hot pressed (VHP) beryllium (Be). The primary mirror diameter is 508 mm with a base radius of curvature of 711.2 mm. This mirror is plated first with electroless nicker and then with electrolytic gold. The purpose of these analyses was (1) to estimate the on-orbit distortion of the large primary mirror due to thermal loading, interface stresses, and gravity release and (2) to calculate the expected damage to the mirror surface due to micrometeoroid impacts. A detailed NASA Structural Analysis Program (NASTRAN) finite element model (FEM) was used as a tool for evaluating the mirror performance. The results of the analyses indicate that a stability error of 2.4 microns Peak-to-Valley (P-V) and 0.6 microns Root Mean Square (RMS) is expected for the on-orbit distortion of the primary mirror surface. The estimated surface damage due to micrometeoroids is 0.03 cm(2), which is 0.002% of the total surface area. Both of these results are within mission acceptance parameters. RP Generie, P (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SYST ANAL BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2245-2 J9 P SOC PHOTO-OPT INS PY 1996 VL 2857 BP 45 EP 56 DI 10.1117/12.258297 PG 12 WC Optics SC Optics GA BG72K UT WOS:A1996BG72K00005 ER PT J AU Tarn, TJ Bejczy, AK De, PK AF Tarn, TJ Bejczy, AK De, PK TI Analysis of the dynamic ability of two robot arms in object handling SO ADVANCED ROBOTICS LA English DT Article; Proceedings Paper CT 4th IFAC Symposium on Robot Control (SYROCO 94) CY SEP 19-21, 1994 CL CAPRI, ITALY SP IFAC Tech Comm Mfg Technol, IFAC Tech Comm Comp, CNR, Progetio Finalizzato Robot, IEEE Robot & Automat Soc, Int Federat Informat Proc, Int Assoc Math & Comp Simulat, Robot Soc Japan ID MANIPULATORS AB To make full use of the increased capability of dual-arm operations, it is necessary to know whether a given object can be manipulated or not along a prespecified trajectory such that the requirement of the joint torques stays within their limits. Furthermore, when dual arms manipulate an object, internal force/moments are generated naturally and different gripping tasks can be performed by tracking given internal force/moment trajectories. In this paper, the feasibility of a given trajectory of the object is analysed by considering a control strategy of the dual-arm system, along with the capability of internal force/moment tracking. Simulation and graphical visualization studies have been carried out to demonstrate the feasibility of this analysis technique. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. LOCKWOOD GREENE ENGINEERS INC,ATLANTA,GA 30303. RP Tarn, TJ (reprint author), WASHINGTON UNIV,DEPT SYST SCI & MATH,ST LOUIS,MO 63130, USA. NR 13 TC 2 Z9 2 U1 0 U2 1 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-1864 J9 ADV ROBOTICS JI Adv. Robot. PY 1996 VL 10 IS 3 BP 301 EP 315 PG 15 WC Robotics SC Robotics GA VF107 UT WOS:A1996VF10700005 ER PT B AU Coles, S Harris, SB AF Coles, S Harris, SB BE Klatz, RM TI Coenzyme Q-10 and lifespan extension SO ADVANCES IN ANTI-AGING MEDICINE, VOL 1 SE ADVANCES IN ANTI-AGING MEDICINE LA English DT Proceedings Paper CT 1994 Conference on Anti-Aging Medicine CY 1994 CL LAS VEGAS, NV SP Amer Acad Anti Aging Med C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MARY ANN LIEBERT INC PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 BN 0-913113-71-9 J9 ADV ANTI AGING MED PY 1996 VL 1 BP 205 EP 215 PG 11 WC Geriatrics & Gerontology; Pharmacology & Pharmacy SC Geriatrics & Gerontology; Pharmacology & Pharmacy GA BE51Q UT WOS:A1996BE51Q00018 ER PT J AU Huang, NE Long, SR Shen, Z AF Huang, NE Long, SR Shen, Z TI The mechanism for frequency downshift in nonlinear wave evolution SO ADVANCES IN APPLIED MECHANICS, VOL 32 SE ADVANCES IN APPLIED MECHANICS LA English DT Review ID INVERSE-SCATTERING-TRANSFORM; KORTEWEG-DEVRIES EQUATION; DEEP-WATER WAVES; SURFACE-WAVES; GRAVITY-WAVES; PHASE; WIND; ENVELOPE; PACKETS C1 NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,OBSERVAT SCI BRANCH,WALLOPS ISL,VA 23337. JOHNS HOPKINS UNIV,DEPT EARTH & PLANETARY SCI,BALTIMORE,MD 21218. RP Huang, NE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,LAB HYDROSPHER PROC,GREENBELT,MD 20771, USA. RI Long, Steven/D-7248-2012 NR 52 TC 118 Z9 131 U1 4 U2 11 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0065-2156 J9 ADV APPL MECH PY 1996 VL 32 BP 59 EP & DI 10.1016/S0065-2156(08)70076-0 PG 62 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BH79G UT WOS:A1996BH79G00002 ER PT J AU Ford, WF Xu, YS Zhao, YH AF Ford, WF Xu, YS Zhao, YH TI Derivative corrections for quadrature formulas SO ADVANCES IN COMPUTATIONAL MATHEMATICS LA English DT Article AB In this paper, we develop corrected quadrature formulas by approximating the derivatives of the integrand that appear in the asymptotic error expansion of the quadrature, using only the function values in the original quadrature rule. A higher order convergence is achieved without computing additional function values of the integrand. C1 NASA,LEWIS RES CTR,RES ANAL CTR,CLEVELAND,OH 44135. N DAKOTA STATE UNIV,DEPT MATH,FARGO,ND 58105. NR 6 TC 4 Z9 4 U1 0 U2 0 PU BALTZER SCI PUBL BV PI AMSTERDAM PA ASTERWEG 1A, 1031 HL AMSTERDAM, NETHERLANDS SN 1019-7168 J9 ADV COMPUT MATH JI Adv. Comput. Math. PY 1996 VL 6 IS 2 BP 139 EP 157 DI 10.1007/BF02127701 PG 19 WC Mathematics, Applied SC Mathematics GA WP757 UT WOS:A1996WP75700003 ER PT B AU Noor, AK AF Noor, AK BE Topping, BHV TI Computational structures technology - Leap frogging into the twenty-first century SO ADVANCES IN COMPUTATIONAL STRUCTURES TECHNOLOGY LA English DT Proceedings Paper CT 3rd International Conference in Computational Structures Technology CY AUG 21-23, 1996 CL BUDAPEST, HUNGARY C1 UNIV VIRGINIA,CTR ADV COMPUTAT TECHNOL,NASA,LANGLEY RES CTR,CHARLOTTESVILLE,VA 22903. NR 0 TC 5 Z9 5 U1 0 U2 0 PU CIVIL COMP PRESS PI EDINBURGH PA 10 SAXE-COBURG PLACE, EDINBURGH, MIDLOTHIAN, SCOTLAND EH3 5BR BN 0-948749-40-7 PY 1996 BP 1 EP 18 PG 18 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods; Engineering, Civil SC Computer Science; Engineering GA BG36V UT WOS:A1996BG36V00001 ER PT B AU Neal, RD AF Neal, RD BE Sobolewski, M Fox, M TI The applicability of proposed object-oriented metrics to developer feedback in time to impact development SO ADVANCES IN CONCURRENT ENGINEERING: CE96: COLLABORATIVE WORK ORGANIZATION AND MANAGEMENT PRODUCT AND PROCESS INTEGRATION PLANNING AND SCHEDULING INFORMATION AND PROCESS MODELING DATA EXCHANGE PRACTICAL APPLICATIONS SE ADVANCES IN CONCURRENT ENGINEERING LA English DT Proceedings Paper CT 3rd ISPE International Conference on Concurrent Engineering - Research and Applications CY AUG 26-28, 1996 CL UNIV TORONTO, TORONTO, CANADA SP Univ Toronto, Int Soc Productiv Enhancements, CERA Journal HO UNIV TORONTO AB This paper looks closely at each of the software metrics generated by the McCabe Object-Oriented Tool(TM) and its ability to convey timely information to developers. The metrics are examined for meaningfulness in terms of the scale assignable to the metric by the rules of measurement theory and the software dimension being measured. Recommendations are made as to the proper use of each metric and its ability to influence development at an early stage. C1 NASA, WVU Software Facil 4&5, Concurrent Engn Res Ctr, Fairmont, WV 26554 USA. RP Neal, RD (reprint author), NASA, WVU Software Facil 4&5, Concurrent Engn Res Ctr, 100 Univ Dr, Fairmont, WV 26554 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-485-8 J9 ADV CONCURRENT ENGN PY 1996 VL 96 BP 403 EP 408 PG 6 WC Engineering, Industrial SC Engineering GA BP73E UT WOS:000086011500052 ER PT B AU Dempsey, PJ Stochl, RJ AF Dempsey, PJ Stochl, RJ BE Kittel, P TI Supplemental Multilayer Insulation Research Facility SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 95 EP 100 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00012 ER PT B AU Stochl, RJ Dempsey, PJ Leonard, KR McIntosh, GE AF Stochl, RJ Dempsey, PJ Leonard, KR McIntosh, GE BE Kittel, P TI Variable density MLI test results SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 101 EP 107 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00013 ER PT B AU Brown, GV DiRusso, E Provenza, AJ AF Brown, GV DiRusso, E Provenza, AJ BE Kittel, P TI An active magnetic bearing with high T-c superconducting coils and ferromagnetic cores SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 973 EP 981 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00125 ER PT B AU Sparr, LM Castles, SH Banks, IS James, EF Gully, WJ Krolichek, EJ Madden, NW Cork, CP Pehl, RH Luke, PN Mallone, DN Hopkins, RA AF Sparr, LM Castles, SH Banks, IS James, EF Gully, WJ Krolichek, EJ Madden, NW Cork, CP Pehl, RH Luke, PN Mallone, DN Hopkins, RA BE Kittel, P TI Spaceflight cryocooler integration issues and techniques SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,CRYOGEN POPULAT & FLUID SYST BRANCH,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1105 EP 1112 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00140 ER PT B AU Breon, SR Branch, HD Blount, GJ Jackson, ML Boyle, RF Tuttle, JG AF Breon, SR Branch, HD Blount, GJ Jackson, ML Boyle, RF Tuttle, JG BE Kittel, P TI Design of the XRS helium insert SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,CRYOGEN PROPULS & FLUID SYST BRANCH,GREENBELT,MD 20771. NR 0 TC 5 Z9 5 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1129 EP 1134 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00143 ER PT B AU Luchik, TS Israelsson, UE Petrac, D Elliott, S AF Luchik, TS Israelsson, UE Petrac, D Elliott, S BE Kittel, P TI Performance improvement of the CHeX flight cryostat SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 4 Z9 4 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1135 EP 1142 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00144 ER PT B AU Lysek, MJ Israelsson, UE Garcia, RD Luchik, TS AF Lysek, MJ Israelsson, UE Garcia, RD Luchik, TS BE Kittel, P TI Cryogenic and thermal aspects of the SIRTF warm launch concept SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 1 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1143 EP 1150 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00145 ER PT B AU Luchik, TS Chave, RG Israelsson, UE Larson, M Lysek, M Nash, AE Hardy, J AF Luchik, TS Chave, RG Israelsson, UE Larson, M Lysek, M Nash, AE Hardy, J BE Kittel, P TI Cryogenic telescope test facility SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1151 EP 1158 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00146 ER PT B AU Paine, CG Petrac, D Rhim, WK AF Paine, CG Petrac, D Rhim, WK BE Kittel, P TI Production of charged and neutral liquid helium drops SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROPULS LAB,PASADENA,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1211 EP 1216 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00153 ER PT B AU Karlmann, P Bard, S Wu, JJ AF Karlmann, P Bard, S Wu, JJ BE Kittel, P TI Development of a periodic 10 K hydrogen sorption cryocooler SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1305 EP 1312 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00164 ER PT B AU Lee, JM Kittel, P Timmerhaus, KD Radebaugh, R AF Lee, JM Kittel, P Timmerhaus, KD Radebaugh, R BE Kittel, P TI Useful scaling parameters for the pulse tube SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1347 EP 1355 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00169 ER PT B AU Roach, PR Kashani, A Lee, JM AF Roach, PR Kashani, A Lee, JM BE Kittel, P TI Theoretical analysis of a pulse tube regenerator SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94037. NR 0 TC 3 Z9 3 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1357 EP 1363 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00170 ER PT B AU Collins, SA Johnson, DL Smedley, GT Ross, RG AF Collins, SA Johnson, DL Smedley, GT Ross, RG BE Kittel, P TI Performance characterization of the TRW 35K pulse tube cooler SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 2 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1471 EP 1478 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00185 ER PT B AU Sparr, L Castles, S James, E Banks, S AF Sparr, L Castles, S James, E Banks, S BE Kittel, P TI Test results for a commercial, low vibration, linear, stirling cycle cryocooler SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,CRYOGEN PROP & FLUID SYST BRANCH,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1569 EP 1576 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00197 ER PT B AU Sparr, L Banks, S James, E Castles, S AF Sparr, L Banks, S James, E Castles, S BE Kittel, P TI NASA/GSFC cryocooler test program results for Ball and Lockheed space flight cryocoolers SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1577 EP 1584 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00198 ER PT B AU DiPirro, MJ Tuttle, JG Shirron, PJ AF DiPirro, MJ Tuttle, JG Shirron, PJ BE Kittel, P TI Development of a high-resolution penetration depth thermometer SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 2 Z9 2 U1 1 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1723 EP 1730 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00216 ER PT B AU Mejia, M Creason, AS Toncich, SS Ebihara, BT Miranda, FA AF Mejia, M Creason, AS Toncich, SS Ebihara, BT Miranda, FA BE Kittel, P TI A single-block TRL test fixture for the cryogenic characterization of planar microwave components SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1731 EP 1738 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00217 ER PT B AU Creason, AS Miranda, FA AF Creason, AS Miranda, FA BE Kittel, P TI Automation of data analysis programs used in the cryogenic characterization of superconducting microwave resonators SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1739 EP 1746 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00218 ER PT B AU Winters, MD Mueller, CH Bhasin, KB Miranda, FA AF Winters, MD Mueller, CH Bhasin, KB Miranda, FA BE Kittel, P TI Characterization of hybrid ferroelectric/HTS thin films for tunable microwave components SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1747 EP 1754 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00219 ER PT B AU Sabataitis, JC Mueller, CH Miranda, FA Warner, J Bhasin, KB AF Sabataitis, JC Mueller, CH Miranda, FA Warner, J Bhasin, KB BE Kittel, P TI YBCO high-temperature superconducting filters on M-plane sapphire substrates SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 2 Z9 2 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1755 EP 1760 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00220 ER PT B AU Jurns, JM Rogers, AC AF Jurns, JM Rogers, AC BE Kittel, P TI Compression mass gauge testing in a liquid hydrogen dewar SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NYMA INC,NASA,LERC GRP,BROOKPARK,OH 44142. NR 0 TC 0 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1803 EP 1811 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00227 ER PT B AU Shirron, PJ DiPirro, MJ Moody, MV Canavan, ER Paik, HJ AF Shirron, PJ DiPirro, MJ Moody, MV Canavan, ER Paik, HJ BE Kittel, P TI Superconducting angular accelerometers for the superconducting gravity gradiometer experiment SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1829 EP 1835 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00231 ER PT B AU Echternach, PM Hahn, I Israelsson, UE AF Echternach, PM Hahn, I Israelsson, UE BE Kittel, P TI A novel silicon micromachined cryogenic capacitive pressure transducer SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1837 EP 1842 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00232 ER PT B AU Nash, AE AF Nash, AE BE Kittel, P TI Simple spreadsheet thermal models for cryogenic applications SO ADVANCES IN CRYOGENIC ENGINEERING, VOL 41, PTS A AND B LA English DT Proceedings Paper CT 1995 Cryogenic Engineering Conference CY JUL 17-21, 1995 CL COLUMBUS, OH SP Battelle Mem Inst, CVI Inc, Lake Shore Cryotron Inc C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45300-2 J9 ADV CRYOG ENG PY 1996 BP 1979 EP 1986 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Engineering; Materials Science; Physics; Polymer Science GA BG31Z UT WOS:A1996BG31Z00250 ER PT S AU Randall, DA Albrecht, B Cox, S Johnson, D Minnis, P Rossow, W Starr, DO AF Randall, DA Albrecht, B Cox, S Johnson, D Minnis, P Rossow, W Starr, DO BE Dmowska, R Saltzman, B TI On fire at ten SO ADVANCES IN GEOPHYSICS, VOL 38 SE Advances in Geophysics LA English DT Review ID OCTOBER 1986 FIRE; MARINE BOUNDARY-LAYER; REFLECTED SOLAR-RADIATION; CLOUD-TOP ENTRAINMENT; HIGH-RESOLUTION RADIOMETER; GENERAL-CIRCULATION MODEL; EFFECTIVE PARTICLE RADIUS; CIRRUS CLOUDS; STRATOCUMULUS CLOUDS; OPTICAL-PROPERTIES C1 PENN STATE UNIV, DEPT METEROL, UNIVERSITY PK, PA 16802 USA. ROYAL AIRCRAFT ESTAB CTR, METEROL RES FLIGHT DIV, FARNBOROUGH, HANTS, ENGLAND. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. RI Rossow, William/F-3138-2015; Randall, David/E-6113-2011; Minnis, Patrick/G-1902-2010 OI Randall, David/0000-0001-6935-4112; Minnis, Patrick/0000-0002-4733-6148 NR 269 TC 22 Z9 22 U1 2 U2 4 PU ELSEVIER ACADEMIC PRESS INC PI SAN DIEGO PA 525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA SN 0065-2687 BN 0-12-018838-4 J9 ADV GEOPHYS JI Adv. Geophys. PY 1996 VL 38 BP 37 EP 177 DI 10.1016/S0065-2687(08)60020-5 PG 141 WC Geochemistry & Geophysics; Geosciences, Multidisciplinary SC Geochemistry & Geophysics; Geology GA BH83A UT WOS:A1996BH83A00002 ER PT S AU Chien, SA AF Chien, SA BE Shadbolt, N OHara, K Schreiber, G TI Intelligent tools for planning knowledge base development and verification SO ADVANCES IN KNOWLEDGE ACQUISITION SE Lecture Notes in Artificial Intelligence LA English DT Article; Proceedings Paper CT 9th European Knowledge Acquisition Workshop on Advances in Knowledge Acquisition (EKAW 96) CY MAY 14-17, 1996 CL NOTTINGHAM, ENGLAND SP MLNet, European Network Excellence Machine Learning, Univ Nottingham, Dept Psychol Artificial Intelligence Grp, Brit Comp Soc, Specialist Grp Expert Syst AB A key obstacle hampering fielding of AI planning applications is the considerable expense of developing, verifying, updating, and maintaining the planning knowledge base (KB). Planning systems must be able to compare favorably in terms of software lifecycle costs to other means of automation such as scripts or rule-based expert systems. Consequently, in order to field real systems, planning practitioners must be able to provide: 1. tools to allow domain experts to create and debug their own planning knowledge bases; 2. tools for software verification, validation, and testing; and 3. tools to facilitate updates and maintenance of the planning knowledge base. This paper describes two types of tools for planning knowledge base development: static KB analysis techniques to detect certain classes of syntactic errors in a planning knowledge base; and completion analysis techniques, to interactively debug the planning knowledge base. We describe these knowledge development tools end describe empirical results documenting the usefulness of these tools. RP Chien, SA (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, M-S 525-3660, PASADENA, CA 91109 USA. NR 18 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-61273-4 J9 LECT NOTES ARTIF INT PY 1996 VL 1076 BP 321 EP 337 PG 17 WC Computer Science, Artificial Intelligence SC Computer Science GA BH80K UT WOS:A1996BH80K00021 ER PT B AU Bird, RK Wallace, TA Brewer, WD AF Bird, RK Wallace, TA Brewer, WD BE Weiss, I Srinivasan, R Bania, PJ Eylon, D Semiatin, SL TI Effects of Heat treatment on microstructure, and toughness of Timetal-21S SO ADVANCES IN THE SCIENCE AND TECHNOLOGY OF TITANIUM ALLOY PROCESSING LA English DT Proceedings Paper CT International Symposium on Advances in the Science and Technology of Titanium Alloy Processing at the 125th TMS Annual Meeting and Exhibition CY FEB 05-08, 1996 CL ANAHEIM, CA SP TMS Titanium & Shaping & Forming Comm AB The effects of heat treatment on the tensile properties and fracture toughness of 0.56-mm-thick Timetal-21S sheet were studied over the temperature range -54 degrees C to +177 degrees C, with the purpose of developing appropriate microstructures and phase distributions to yield high strengths with as high a toughness as possible. beta and alpha/beta anneals with various quenches and ages, as well as direct aging, were investigated. beta-annealing, water-quenching and aging generally produced microstructures of fine alpha plates within the beta matrix resulting in the beat combinations of strength and toughness. alpha/beta annealing and aging resulted in thick grain boundary alpha with an associated low toughness. Law temperature ages tended to produce omega phase and low toughness. The mechanical behavior of the Timetal-21S sheet was highly dependent upon temperature, but the properties over the temperature range studied seemed to follow the same general strength/toughness trends as the room temperature properties. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bird, RK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-324-4 PY 1996 BP 473 EP 480 PG 8 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA BM47L UT WOS:000078852200042 ER PT B AU Li, Q Crooks, R AF Li, Q Crooks, R BE Weiss, I Srinivasan, R Bania, PJ Eylon, D Semiatin, SL TI Isothermal decomposition of Timetal 21s SO ADVANCES IN THE SCIENCE AND TECHNOLOGY OF TITANIUM ALLOY PROCESSING LA English DT Proceedings Paper CT International Symposium on Advances in the Science and Technology of Titanium Alloy Processing at the 125th TMS Annual Meeting and Exhibition CY FEB 05-08, 1996 CL ANAHEIM, CA SP TMS Titanium & Shaping & Forming Comm ID OMEGA PHASE TRANSFORMATION; MORPHOLOGY; BETA AB The decomposition of the metastable beta-phase titanium alloy Timetal-21s was studied by transmission electron microscopy after beta solution, quenching and isothermal aging at temperatures ranging from 450 degrees C - 565 degrees C. These results were compared to available strength and toughness data. Diffraction patterns indicated the presence of athermal omega-phase in the as-quenched condition; with type I alpha, and then type II alpha, developing after further aging. Several stages were observed in the precipitation and growth of alpha, and these were characterized by their morphologic and crystallographic changes. In early stages, some of the alpha were observed in triangular-cross-section, prism-shaped structures formed by the junction of three twin-related alpha variants. Further aging produced alpha plates joined in "V" shapes. Single variant plates of type I alpha were also seen in aged material. The formation of the tri-variant alpha differs from the single variant variety by the operation of a sympathetic nucleation mechanism, probably associated with the low energy of the alpha/alpha coherent twin interface. Material heat treated to produce triangular alpha and low volume fractions of type II alpha exhibited relatively low toughness. C1 Analyt Serv & Mat Inc, Met Mat Branch, NASA Langley Res Ctr, Hampton, VA 23666 USA. RP Li, Q (reprint author), Analyt Serv & Mat Inc, Met Mat Branch, NASA Langley Res Ctr, Hampton, VA 23666 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-324-4 PY 1996 BP 481 EP 488 PG 8 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA BM47L UT WOS:000078852200043 ER PT B AU Gatski, TB AF Gatski, TB BE Gavrilakis, S Machiels, L Monkewitz, PA TI Airfoil stall prediction using a two-equation and an explicit algebraic stress model SO ADVANCES IN TURBULENCES VI SE FLUID MECHANICS AND ITS APPLICATIONS LA English DT Proceedings Paper CT 6th European Turbulence Conference CY JUL 02-05, 1996 CL SWISS FED INST TECHNOL, LAUSANNE, SWITZERLAND SP EUROMECH, ERCOFTAC, COST HO SWISS FED INST TECHNOL RP Gatski, TB (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4132-5 J9 FLUID MEC A PY 1996 VL 36 BP 163 EP 166 PG 4 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BH48H UT WOS:A1996BH48H00045 ER PT J AU Balling, RJ SobieszczanskiSobieski, J AF Balling, RJ SobieszczanskiSobieski, J TI Optimization of coupled systems: A critical overview of approaches SO AIAA JOURNAL LA English DT Article ID SENSITIVITY ANALYSIS; DESIGN; AIRCRAFT C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RP Balling, RJ (reprint author), BRIGHAM YOUNG UNIV, DEPT CIVIL & ENVIRONM ENGN, PROVO, UT 84602 USA. RI UF, MDO/G-8720-2012 NR 28 TC 119 Z9 134 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 1996 VL 34 IS 1 BP 6 EP 17 DI 10.2514/3.13015 PG 12 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900002 ER PT J AU Garrison, TJ Settles, GS Narayanswami, N Knight, DD Horstman, CC AF Garrison, TJ Settles, GS Narayanswami, N Knight, DD Horstman, CC TI Flowfield surveys and computations of a crossing-shock wave boundary-layer interaction SO AIAA JOURNAL LA English DT Article ID TURBULENT; EQUATIONS; FLOW AB A joint experimental and computational study has been performed to investigate the B flowfield structure created by two crossing oblique shock waves interacting with a turbulent boundary layer. Such an interaction is of practical importance in the design of high-speed sidewall-compression inlets. The interaction is created by a test model, consisting of two sharp fins mounted at 15-deg angle of attack to a Bat plate, placed in a Mach 3.85 freestream flow with a unit Reynolds number of 76 x 10(6)/m. Two computational solutions, one using a Baldwin-Lomax algebraic turbulent eddy viscosity model and one using a modified kappa-epsilon (Rodi) turbulence model, are compared with experimental flowfield data obtained from a fast-response five-hole probe, Both the experiment and the computations show that the flowfield is dominated by a large, low-Mach-number, low-total-pressure separated region located on the interaction centerline, A comparison of the results shows significant differences between experiment and computations within this separated region, Outside the separated region, the experiment and computations are in good agreement. Additionally, the comparison shows that both turbulence models provide similar results, with neither model being clearly superior in predicting the flowfield. C1 PENN STATE UNIV,GAS DYNAM LAB,UNIVERSITY PK,PA 16802. RUTGERS STATE UNIV,PISCATAWAY,NJ 08903. NASA,AMES RES CTR,FLUID DYNAM DIV,MOFFETT FIELD,CA 94035. RP Garrison, TJ (reprint author), LOUISIANA STATE UNIV,BATON ROUGE,LA 70803, USA. NR 30 TC 8 Z9 8 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 JAN PY 1996 VL 34 IS 1 BP 50 EP 56 DI 10.2514/3.13020 PG 7 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900007 ER PT J AU Garrison, TJ Settles, GS Horstman, CC AF Garrison, TJ Settles, GS Horstman, CC TI Measurements of the triple shock wave turbulent boundary-layer interaction SO AIAA JOURNAL LA English DT Article AB A joint experimental and computational study has investigated the flowfield structure created by three crossing oblique shock waves interacting with a turbulent boundary layer, Such an interaction is of practical importance in the design of high-speed sidewall-compression inlets. The interaction is created by a test model consisting of two vertical sharp fins mounted at 15-deg angle of attack to a horizontal flat plate. A third compression surface of 10-deg angle is mounted to the plate between the two vertical fins. The Mach 3.85 flowfield is examined experimentally through kerosene lampblack and planar laser scattering visualizations. The results are used to develop a flowfield model of the interaction structure. This structure is found to consist of a complex wave pattern overlying a viscous separated region. The presence of the 10-deg compression ramp reduces the severity of the boundary-layer separation compared to interactions created by the two fins alone, Additionally, the experimental flowfield data are compared with a computational solution using a modified kappa-epsilon (Rodi) turbulence model. A comparison of the results shows that, despite the complexity of the flowfield, the computed solution does reveal several of the key flow features observed experimentally. C1 PENN STATE UNIV,DEPT MECH ENGN,UNIVERSITY PK,PA 16802. PENN STATE UNIV,GAS DYNAM LAB,UNIVERSITY PK,PA 16802. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Garrison, TJ (reprint author), LOUISIANA STATE UNIV,DEPT MECH ENGN,BATON ROUGE,LA 70803, USA. NR 27 TC 7 Z9 9 U1 0 U2 2 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 JAN PY 1996 VL 34 IS 1 BP 57 EP 64 DI 10.2514/3.12864 PG 8 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900008 ER PT J AU Patnaik, SN Kaljevic, I Hopkins, DA Saigal, S AF Patnaik, SN Kaljevic, I Hopkins, DA Saigal, S TI Completed Beltrami-Michell formulation for analyzing mixed boundary value problems in elasticity SO AIAA JOURNAL LA English DT Article ID INTEGRATED FORCE METHOD AB In elasticity, the method of forces, wherein stress parameters are considered as the primary unknowns, is known as the Beltrami-Michell formulation, The Beltrami-Michell formulation can only solve stress boundary value problems; it cannot handle the more prevalent displacement or mixed boundary value problems of elasticity. Therefore, this formulation, which has restricted application, could not become a true alternative to the Navier displacement method, which can solve all three types of boundary value problems, The restrictions of the Beltrami-Michell formulation have been alleviated by augmenting the classical formulation with a novel set of conditions identified as the boundary compatibility conditions. This new method, which completes the classical force formulation, has been termed the completed Beltrami-Michell formulation, The completed Beltrami-Michell formulation can solve general elasticity problems, with stress, displacement, and mixed boundary conditions in terms of stresses as the primary unknowns. The completed Beltrami-Michell formulation is derived from the stationary condition of the variational functional of the integrated force method, In the completed Beltrami-Michell formulation, stresses for kinematically stable structures can be obtained without any reference to displacements either in the field or on the boundary, This paper presents the completed Beltrami-Michell formulation and its derivation from the variational functional of the integrated force method, Examples are presented to demonstrate the applicability of the completed formulation for analyzing mixed boundary value problems under thermomechanical loads. Selected examples include analysis of a composite cylindrical shell, wherein membrane and bending response are coupled, and a composite circular plate. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CARNEGIE MELLON UNIV,PITTSBURGH,PA 15213. RP Patnaik, SN (reprint author), OHIO AEROSP INST,22800 CEDAR POINT RD,CLEVELAND,OH 44142, USA. NR 12 TC 7 Z9 7 U1 0 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 JAN PY 1996 VL 34 IS 1 BP 143 EP 148 DI 10.2514/3.13034 PG 6 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900021 ER PT J AU Librescu, L Lin, W Nemeth, MP Starnes, JH AF Librescu, L Lin, W Nemeth, MP Starnes, JH TI Frequency-load interaction of geometrically imperfect curved panels subjected to heating SO AIAA JOURNAL LA English DT Article ID VIBRATIONS; PLATES AB The results of a parametric study of the vibration behavior of flat and shallow curved panels subjected to temperature fields and mechanical loads are presented, The mechanical loads include uniform axial-compression prebuckling loads and transverse lateral pressure. The temperature fields include spatially nonuniform heating over the panel surfaces and a linear through-the-thickness temperature gradient. The structural analysis used for the study is based on a higher order transverse-shear-deformation shallow-shell theory that includes the effects of geometric nonlinearities and initial geometric imperfections. Analytical results are presented for simply supported single-layer and three-layer panels made from transversely isotropic materials. The results identify the interaction of the applied thermal and mechanical loads with the fundamental frequencies in both the prebuckling and postbuckling equilibrium states. The results indicate that initial geometric imperfections, transverse-shear flexibility, and changes in curvature are important contributors to the response of a panel for a wide range of structural and loading parameters. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP Librescu, L (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061, USA. NR 23 TC 28 Z9 28 U1 0 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 JAN PY 1996 VL 34 IS 1 BP 166 EP 177 DI 10.2514/3.13037 PG 12 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900024 ER PT J AU Reeder, MF Zaman, KBMQ AF Reeder, MF Zaman, KBMQ TI Impact of tab location relative to the nozzle exit on jet distortion SO AIAA JOURNAL LA English DT Article RP Reeder, MF (reprint author), NASA,LEWIS RES CTR,OPT MAT SYST BRANCH,MS 77-1,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 7 TC 10 Z9 12 U1 0 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 JAN PY 1996 VL 34 IS 1 BP 197 EP 199 DI 10.2514/3.13044 PG 3 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900031 ER PT J AU Bragg, MB Heinrich, DC Balow, FA Zaman, KBMQ AF Bragg, MB Heinrich, DC Balow, FA Zaman, KBMQ TI Flow oscillation over an airfoil near stall SO AIAA JOURNAL LA English DT Article C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Bragg, MB (reprint author), UNIV ILLINOIS,DEPT AERONAUT & ASTRONAUT ENGN,URBANA,IL 61801, USA. NR 10 TC 21 Z9 21 U1 0 U2 2 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 JAN PY 1996 VL 34 IS 1 BP 199 EP 201 PG 3 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900032 ER PT J AU Richard, JC Fralick, GC AF Richard, JC Fralick, GC TI Use of drag probe in supersonic flow SO AIAA JOURNAL LA English DT Article RP Richard, JC (reprint author), NASA,LEWIS RES CTR,INSTRUMENTAT & CONTROL TECHNOL DIV,CLEVELAND,OH 44135, USA. NR 8 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 JAN PY 1996 VL 34 IS 1 BP 201 EP 203 DI 10.2514/3.13046 PG 3 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900033 ER PT J AU Speziale, CG Abid, R AF Speziale, CG Abid, R TI Near-wall integration of Reynolds stress turbulence closures with no wall damping (vol 33, pg 1974, 1995) SO AIAA JOURNAL LA English DT Correction, Addition C1 HIGH TECHNOL CORP,NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP Speziale, CG (reprint author), BOSTON UNIV,BOSTON,MA 02215, 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 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 1996 VL 34 IS 1 BP 212 EP 212 PG 1 WC Engineering, Aerospace SC Engineering GA TP059 UT WOS:A1996TP05900039 ER PT B AU McNally, BD Sridhar, B AF McNally, BD Sridhar, B BE Otto, RG Lenz, J Targ, R TI Technologies for user preferred routing SO AIR TRAFFIC CONTROL TECHNOLOGIES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Air Traffic Control Technologies II Conference CY APR 10-11, 1996 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2118-9 J9 P SOC PHOTO-OPT INS PY 1996 VL 2737 BP 63 EP 64 DI 10.1117/12.241063 PG 2 WC Engineering, Aerospace; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BF76R UT WOS:A1996BF76R00007 ER PT B AU Schlickenmaier, H AF Schlickenmaier, H BE Otto, RG Lenz, J Targ, R TI Overview of NASA airspace-related research and technology SO AIR TRAFFIC CONTROL TECHNOLOGIES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Air Traffic Control Technologies II Conference CY APR 10-11, 1996 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE aeronautics; flight systems; avionics; air traffic management; airspace operations; free flight; integrated aviation C1 NASA,OFF AERONAUT,WASHINGTON,DC 20546. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2118-9 J9 P SOC PHOTO-OPT INS PY 1996 VL 2737 BP 116 EP 121 DI 10.1117/12.241059 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BF76R UT WOS:A1996BF76R00013 ER PT J AU Convertino, VA Engelke, KA Ludwig, DA Doerr, DF AF Convertino, VA Engelke, KA Ludwig, DA Doerr, DF TI Restoration of plasma volume after 16 days of head-down tilt induced by a single bout of maximal exercise SO AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY LA English DT Article DE blood volume; bedrest; spaceflight; renal function; fluid-electrolyte balance ID TRAINING-INDUCED HYPERVOLEMIA; BED REST; SPACE-FLIGHT; ELECTROLYTE SHIFTS; VENOUS-PRESSURE; FLUID; WEIGHTLESSNESS; VASOPRESSIN; OSMOLALITY; RESPONSES AB Seven healthy men performed maximal exercise 24 h before the end of 16 days exposure to 6 degrees head-down tilt (HDT) to test the hypothesis that such an exercise technique could restore plasma volume (PV) at the end of a simulated space mission. Exercise consisted of supine cycling with graded work rates increasing by 16 W/min to volitional fatigue and required an average of 16 min. The experimental protocol was a standard cross-over design in which the order of treatment (exercise or control) was counterbalanced across all seven subjects. PV, fluid intake (ad libitum), urine output, renal function, and hormones associated with fluid homeostasis were measured before HDT, 24 h before the end of HDT just prior to exercise, and at the end of HDT 24 h after exercise. HDT reduced PV by 16% in both control and exercise conditions. Maximal exercise completely restored plasma volume within 24 h to 3.9 +/- 3.2% of pre-HDT levels despite continued HDT. Compared with control, exercise induced a 660-ml larger positive fluid balance because of greater fluid intake and reduced urine volume during the 24 h after exercise. These results suggest that one bout of maximal leg exercise before return from 16 days of spaceflight may be completely effective in stimulating thirst and restoring plasma volume to preflight levels. C1 UNIV N CAROLINA, DEPT MATH & STAT, GREENSBORO, NC 27412 USA. NASA, KENNEDY SPACE CTR, CAPE CANAVERAL, FL 32899 USA. UNIV FLORIDA, DEPT PHYSIOL, GAINESVILLE, FL 32610 USA. RP Convertino, VA (reprint author), AL AOCY, DIV CLIN SCI, PHYSIOL RES BRANCH, 2507 KENNEDY CIRCLE, BROOKS AFB, TX 78235 USA. NR 37 TC 29 Z9 31 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0363-6119 J9 AM J PHYSIOL-REG I JI Am. J. Physiol.-Regul. Integr. Comp. Physiol. PD JAN PY 1996 VL 270 IS 1 BP R3 EP R10 PG 8 WC Physiology SC Physiology GA TT097 UT WOS:A1996TT09700002 PM 8769779 ER PT J AU Rambal, S Damesin, C Joffre, R Methy, M LoSeen, D AF Rambal, S Damesin, C Joffre, R Methy, M LoSeen, D TI Optimization of carbon gain in canopies of Mediterranean evergreen oaks SO ANNALES DES SCIENCES FORESTIERES LA English DT Article; Proceedings Paper CT International Symposium on Oaks in a Changing Environment - Ecological and Physiological Aspects CY SEP, 1994 CL VELAINE-EN-HAYE, FRANCE SP Int Union Forest Res Org, Eurosilva Eureka 447, European Initiat Forest Tree Physiol, Conseil Reg Lorraine, INRA, Cent Adm, Dist Agglomerat Nanceenne, Conseil Gen Meurthe et Moselle, Nancy City Council DE Mediterranean evergreen canopy; leaf mass per area; photosynthesis-related leaf property; Quercus ilex; Quercus coccifera ID LEAF NITROGEN; CHLOROPHYLL FLUORESCENCE; PHOTOSYNTHETIC CAPACITY; DECIDUOUS FOREST; PLANTS; REFLECTANCE; LEAVES; LIMITATIONS; PATTERNS; ISOTOPE AB The main goal of this study was to analyze the depth-distribution of leaf mass per area (LMA) measured in ten canopies of Mediterranean evergreen oaks, five canopies of Quercus coccifera and five canopies of Q ilex, across soil water availability gradients in southern France, Spain and Portugal. There was a significant site effect on LMA with values being lower in mesic sites compared to those on xeric sites. In all canopies, LMA decreased by up to 50% from the top to the bottom. The relationships between cumulative leaf area index and LMA could be represented by an exponential function. For two canopies of Q ilex growing in contrasting environments, we analyzed the interrelationships among LMA, mass-based nitrogen, mass-based metabolic versus structural (total fiber) content, photosynthetic electron transport and carbon isotope composition. There was no difference in mass-based nitrogen or fiber content among upper and lower canopy positions in both locations. The maximum quantum yield of linear electron flow can be considered to be constant within the canopy. The area-based maximal electron transport rate and the carbon isotope composition were significantly linearly related to the LMA. Finally, we tested whether the observed depth-distribution follows the pattern suggested by some optimization theories. C1 NASA,JET PROP LAB,PASADENA,CA 91109. RP Rambal, S (reprint author), CNRS,CTR ECOL FONCT & EVOLUT,BP 5051,F-34033 MONTPELLIER,FRANCE. RI Lo Seen, Danny/C-2679-2008; JOFFRE, Richard/C-1600-2014 OI Lo Seen, Danny/0000-0002-7773-2109; JOFFRE, Richard/0000-0001-8205-7710 NR 48 TC 27 Z9 27 U1 2 U2 7 PU EDITIONS SCIENTIFIQUES ELSEVIER PI PARIS CEDEX 15 PA 141 RUE JAVEL, 75747 PARIS CEDEX 15, FRANCE SN 0003-4312 J9 ANN SCI FOREST JI Ann. Sci. For. PY 1996 VL 53 IS 2-3 BP 547 EP 560 DI 10.1051/forest:19960234 PG 14 WC Forestry SC Forestry GA UT402 UT WOS:A1996UT40200035 ER PT J AU Bell, LD Kaiser, WJ AF Bell, LD Kaiser, WJ TI Ballistic-electron-emission microscopy: A nanometer-scale probe of interfaces and carrier transport SO ANNUAL REVIEW OF MATERIALS SCIENCE LA English DT Review DE scanning tunneling microscopy; semiconductor interfaces; hot-electron transport; semiconductor heterostructures; band structure ID SCANNING-TUNNELING-MICROSCOPE; SCHOTTKY-BARRIER HEIGHT; METAL-SEMICONDUCTOR INTERFACES; MOLECULAR-BEAM EPITAXY; GOLD-SILICON INTERFACE; MIXED-PHASE CONTACTS; DENSITY-OF-STATES; ELASTIC-SCATTERING; IMPACT IONIZATION; BAND-STRUCTURE AB Ballistic-electron-emission microscopy (BEEM) is a relatively new technique for the investigation of semiconductor interfaces and energetic carrier transport over a wide energy range about the Fermi level. Because BEEM is based on scanning tunneling microscopy, which provides an atomic-scale probe of surfaces, it can resolve interface properties with nanometer-scale spatial resolution. BEEM techniques have been applied to the spatially resolved measurement of Schottky barrier height and to the energy spectroscopy of hot carrier transport in metal/semiconductor devices. C1 UNIV CALIF LOS ANGELES,DEPT ELECT ENGN,LOS ANGELES,CA 90095. RP Bell, LD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 118 TC 70 Z9 70 U1 1 U2 9 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 0084-6600 J9 ANNU REV MATER SCI JI Annu. Rev. Mater. Sci. PY 1996 VL 26 BP 189 EP 222 PG 34 WC Materials Science, Multidisciplinary SC Materials Science GA VB465 UT WOS:A1996VB46500010 ER PT J AU Said, MA Thomas, V AF Said, MA Thomas, V GP SOC PLAST ENGINEERS INC TI Mechanical behavior of polyester nonwoven composite films SO ANTEC '96: PLASTICS - RACING INTO THE FUTURE, VOLS I-III: VOL I: PROCESSING; VOL II: MATERIALS; VOL III: SPACIAL AREAS SE SOCIETY OF PLASTICS ENGINEERS TECHNICAL PAPERS LA English DT Proceedings Paper CT 54th Annual Technical Conference of the Society-of-Plastics-Engineers - Plastics: Racing into the Future (ANTEC 96) CY MAY 05-10, 1996 CL INDIANAPOLIS, IN SP Soc Plast Engineers DE nonwovens; polyester films; mechanical properties; thin films; lamination; composite films; SRIM AB Films reinforced with nonwoven fabric are being considered for the development of a material suitable for long duration scientific balloons under a program managed by the National Aeronautics and Space Administration (NASA). Nonwoven fabrics provide a relatively high strength to weight ratio compared to other woven fabrics or homogenous films. Nonwovens also have better crack propagation resistance and rip stop capabilities when compared to similar light weight, high strength materials. If joining is required, such as in the case of scientific balloons, they have the advantage over polymeric thin films to utilize traditional textile methods as well as other methods such as hot sealing, adhesion, and ultrasonic means. Nonwovens however, lack the barrier properties required for helium filled scientific balloons. Because the fabric is porous, it muse be laminated to provide the gas barrier capabilities required in these applications. A set of polyester nonwovens with and without a scrim, laminated with thin mylar film as a barrier were tested and their mechanical properties were compared to that of the individual layers. The data indicate that, while maintaining the low weight characteristics, there is a net increase in the strength and toughness of the composite film, compared to that of the nonwoven fabric or the mylar film alone. RP Said, MA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC PLASTICS ENGINEERS PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06805 J9 SOC PLAST E PY 1996 VL 42 BP 2468 EP 2472 PG 5 WC Engineering, Chemical; Engineering, Mechanical; Materials Science, Multidisciplinary; Polymer Science SC Engineering; Materials Science; Polymer Science GA BH28W UT WOS:A1996BH28W00432 ER PT S AU Mattikalli, NM Engman, ET Ahuja, LR Jackson, TJ AF Mattikalli, NM Engman, ET Ahuja, LR Jackson, TJ BE Kovar, K Nachtnebel, HP TI A GIS for spatial and temporal monitoring of microwave remotely sensed soil moisture and estimation of soil properties SO APPLICATION OF GEOGRAPHIC INFORMATION SYSTEMS IN HYDROLOGY AND WATER RESOURCES MANAGEMENT SE IAHS PUBLICATIONS LA English DT Proceedings Paper CT Conference on the Application of Geographic Information Systems in Hydrology and Water Resources Management (HydroGIS 96) CY APR 16-19, 1996 CL VIENNA, AUSTRIA SP Univ Bodenkultur, Inst Wasserwirtsch Hydrol & Konstruktiven, Vienna, Int Assoc Hydrol Sci, Int Commiss Groundwater, IAHS, Int Comm Remote Sensing & Data Transmiss, UNESCO, Div Water Sci, Int Assoc Hydrogeologists, Int Ground Water Modeling Ctr, Int Inst Appl Syst Anal, Austria, Amer Soc Testing & Mat, Amer Soc Photogrammetry & Remote Sensing, Austrian Hydrol Soc, Int Assoc Hydraul Res C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,LAB HYDROSPHER PROC,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 1 U2 1 PU INT ASSOC HYDROLOGICAL SCIENCES PI WALLINGFORD PA INST OF HYDROLOGY, WALLINGFORD, ENGLAND OX10 8BB SN 0144-7815 BN 0-947571-84-1 J9 IAHS-AISH P PY 1996 IS 235 BP 621 EP 628 PG 8 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BF89F UT WOS:A1996BF89F00074 ER PT B AU Fang, WC Sheu, BJ Wall, J AF Fang, WC Sheu, BJ Wall, J BE Rogers, SK Ruck, DW TI On-board neural processor design for an intelligent multi-sensor microspacecraft SO APPLICATIONS AND SCIENCE OF ARTIFICIAL NEURAL NETWORKS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE International Conference on Applications and Science of Artificial Neural Networks II CY APR 09-12, 1996 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE array processors; image sensor; multichip module; neural networks; optoelectronic integrated circuit; parallel processing; small satellite; microspacecraft; smart pixels; VLSI C1 CALTECH,JET PROP LAB,ADV COMP RESOURCES GRP,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2141-3 J9 P SOC PHOTO-OPT INS PY 1996 VL 2760 BP 577 EP 588 DI 10.1117/12.235947 PG 12 WC Computer Science, Artificial Intelligence; Optics; Physics, Applied SC Computer Science; Optics; Physics GA BF31U UT WOS:A1996BF31U00059 ER PT B AU Rahman, ZU Jobson, DJ Woodell, GA AF Rahman, ZU Jobson, DJ Woodell, GA BE Tescher, AG TI A multiscale retinex for color rendition and dynamic range compression SO APPLICATIONS OF DIGITAL IMAGE PROCESSING XIX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Applications of Digital Image Processing XIX CY AUG 07-09, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers AB The human vision system performs the tasks of dynamic range compression and color constancy almost effortlessly. The same tasks pose a very challenging problem for imaging systems whose dynamic range is restricted by either the dynamic response of film, in case of analog cameras, or by the analog-to-digital converters, in the case of digital cameras. The images thus formed are unable to encompass the wide dynamic range present in most natural scenes (often > 500:1). Whereas the human visual system is quite tolerant to spectral changes in lighting conditions, these strongly affect both the film response for analog cameras and the filter responses for digital cameras, leading to incorrect color formulation in the acquired image. Our multiscale retinex, based in part on Edwin Land's work on color constancy, provides a fast, simple, and automatic technique for simultaneous dynamic range compression and accurate color rendition. The retinex algorithm is non-linear, and global-output at a point is also a function of its surround-in extent. A comparison with conventional dynamic range compression techniques such as the application of point non-linearities, e.g. log(x, y), and global histogram equalization and/or modification shows that the multiscale retinex simultaneously provides the best dynamic range compression and color rendition. The applications of such an algorithm are many; from medical imaging to remote sensing; and from commercial photography to color transmission. RP Rahman, ZU (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 34 Z9 34 U1 0 U2 6 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2235-5 J9 P SOC PHOTO-OPT INS PY 1996 VL 2847 BP 183 EP 191 DI 10.1117/12.258224 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BG84J UT WOS:A1996BG84J00018 ER PT J AU Johnson, WS Li, EW Miller, JL AF Johnson, WS Li, EW Miller, JL TI High temperature hybrid titanium composite laminates: An early analytical assessment SO APPLIED COMPOSITE MATERIALS LA English DT Article DE titanium; composites; laminates; adhesives; fibers AB This paper presents a new type of material system that shows great promise for aerospace applications. The concept consists of thin sheets of titanium bonded together with a polymer composite prepreg consisting of a high temperature resin reinforced with high or intermediate modulus fibers. The potential material performance is outstanding in terms of in-plane fatigue and fracture. As with all composite materials, the exact moduli and strength can be optimized for a given application by varying the constituents, their volume fractions and, in the case of the reinforcing fibers, their orientation. The paper includes analytical studies as well as experimental results. C1 NASA, LANGLEY RES CTR, MECH MAT BRANCH, HAMPTON, VA 23665 USA. GEORGIA INST TECHNOL, SCH MAT SCI & ENGN, ATLANTA, GA 30332 USA. NR 15 TC 13 Z9 14 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-189X J9 APPL COMPOS MATER JI Appl. Compos. Mater. PY 1996 VL 3 IS 6 BP 379 EP 390 PG 12 WC Materials Science, Composites SC Materials Science GA WT811 UT WOS:A1996WT81100003 ER PT J AU Tsynkov, SV AF Tsynkov, SV TI An effective numerical technique for solving a special class of ordinary difference equations (vol 18, pg 489, 1995) SO APPLIED NUMERICAL MATHEMATICS LA English DT Correction, Addition RP Tsynkov, SV (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 128,HAMPTON,VA 23681, USA. NR 1 TC 0 Z9 0 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 JAN PY 1996 VL 19 IS 4 BP 509 EP 509 DI 10.1016/0168-9274(95)00112-3 PG 1 WC Mathematics, Applied SC Mathematics GA UA376 UT WOS:A1996UA37600007 ER PT J AU Vlasse, M Golben, J Decher, R AF Vlasse, M Golben, J Decher, R TI Process optimization for 123 and Bi-based superconductors SO APPLIED SUPERCONDUCTIVITY LA English DT Article ID CU-O SYSTEM; ZERO RESISTANCE; OXIDE; TRANSITION; OXIDATION; PRECURSOR; YBA2CU3OX; PB AB The development of pure phase 123 and Bi-based 2223 superconductors has been optimized. The pre-heat processing appears to be a very important parameter in achieving this objective. In addition, the synthesis of pure phases in the Bi-based system involves effects due to oxygen partial pressure, time and temperature. The optimization of this processing is a key step towards the successful continuation of the superconducting materials development, i.e. in substitutions, c-axis orientation, melt-sintering processes, and in synthesizing single crystals. An example of optimized bulk substitution is the 70% limit of Sr for Ba substitution in the yttrium-based 123 superconductor. In a nominal composition containing no barium, a majority 123 phase has also been observed, though this phase is apparently not superconducting. In the Bi-based system, substitution of Sb and Pb for Bi has been obtained in the 2223 phase. The Sb substitution into the pure phase has no apparent advantage over the parent Bi compound or the Pb-substituted phase. Orientation/melt-sintering effects include the extreme c-axis orientation of yttrium 123 and of the bisumuth 2223, 2212 and 2201 phases. Surface orientation of all three Bi-based phases can be obtained from one sample of a specific nominal bulk composition. The surface orientation for both series of samples is dependent upon a number of factors including pre- heat processing, exact composition and/or extraneous phases present, heat rates, temperatures, and times. A procedure for establishing Sr substitution for Ba into 123 single crystals has been determined. Systematic substitution of up to 30% Sr for Ba in the structure has been successful. This procedure as well as those above will be described and discussed. C1 SCI & TECHNOL CORP,HUNTSVILLE,AL. RP Vlasse, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 25 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 0964-1807 J9 APPL SUPERCOND JI Appl. Supercond. PD JAN-FEB PY 1996 VL 4 IS 1-2 BP 79 EP 93 DI 10.1016/0964-1807(96)00015-4 PG 15 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA VF648 UT WOS:A1996VF64800009 ER PT J AU Hedli, CC Rao, NR Reuhl, KR Witmer, CM Snyder, R AF Hedli, CC Rao, NR Reuhl, KR Witmer, CM Snyder, R TI Effects of benzene metabolite treatment on granulocytic differentiation and DNA adduct formation in HL-60 cells SO ARCHIVES OF TOXICOLOGY LA English DT Article DE benzene; metabolite; granulocytic differentiation; DNA adducts; HL-60 cells ID HUMAN BONE-MARROW; HYDROQUINONE; BINDING; RAT; BENZOQUINONE; MACROPHAGES; EXPRESSION; INVITRO; DAMAGE; LIVER AB Reactive metabolites of benzene (BZ) play important roles in BZ-induced hematotoxicity. Although reactive metabolites of BZ covalently bind to DNA, the significance of DNA adduct formation in the mechanism of BZ toxicity is not clear. These studies investigated the covalent binding of the BZ metabolites hydroquinone(HQ) and 1,2,4-benzenetriol(BT) using the DNA [P-32]postlabeling method and explored the potential relationship between DNA adduct formation and cell differentiation in human promyelocytic leukemia (HL-60) cells, a model system for studying hematopoiesis. Maturation of HL-60 cells to granulocytes, as assessed by light and electron microscopy, was significantly inhibited in cells that were pretreated with HQ or BT prior to inducing differentiation with retinoic acid (RA). The capacity of RA-induced cells to phagocytose sheep red blood cells (RBC) and to reduce nitroblue tetrazolium (NET), two functional parameters characteristic of mature, differentiated neutrophils, was also inhibited in cells pretreated with HQ or BT. These BZ metabolite treatments induced DNA adduct formation in HQ- but not in BT-treated cells. These results indicate that whereas HQ and BT each block granulocytic differentiation in HL-60 cells, DNA adducts were observed only following HQ treatment. Thus DNA adduct formation may be important in HQ but not in BT toxicity. C1 RUTGERS STATE UNIV,UMDNJ,RWJMS,JOINT GRAD PROGRAM TOXICOL,PISCATAWAY,NJ 08854. NASA,LYNDON B JOHNSON SPACE CTR,DEPT PHARMACOL,HOUSTON,TX 77058. FU NIEHS NIH HHS [ESO7148, ESO5022] NR 32 TC 22 Z9 25 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0340-5761 J9 ARCH TOXICOL JI Arch. Toxicol. PD JAN PY 1996 VL 70 IS 3-4 BP 135 EP 144 DI 10.1007/s002040050252 PG 10 WC Toxicology SC Toxicology GA TR762 UT WOS:A1996TR76200001 PM 8825669 ER PT B AU Rogers, JL McCulley, CM Bloebaum, CL AF Rogers, JL McCulley, CM Bloebaum, CL BE Gero, JS Sudweeks, F TI Integrating a genetic algorithm into a knowledge-based system for ordering complex design processes SO ARTIFICIAL INTELLIGENCE IN DESIGN '96 LA English DT Proceedings Paper CT 4th International Conference on Artificial Intelligence in Design CY JUN, 1996 CL STANFORD, CA AB The design cycle associated with large engineering systems requires an initial decomposition of the complex system into design processes which are coupled through the transference of output data. Some of these design processes may be grouped into iterative subcycles. In analyzing or optimizing such a coupled system, it is essential to be able to determine the best ordering of the processes within these subcycles to reduce design cycle time and cost. Many decomposition approaches assume the capability is available to determine what design processes and couplings exist and what order of execution will be imposed during the design cycle. Unfortunately, this is often a complex problem and beyond the capabilities of a human design manager. A new feature, a genetic algorithm, has been added to DeMAID (Design Manager's Aid for Intelligent Decomposition) to allow the design manager to rapidly examine many different combinations of ordering processes in an iterative subcycle and to optimize the ordering based on cost, time, and iteration requirements. Two sample test cases are presented to show the effects of optimizing the ordering with a genetic algorithm. RP Rogers, JL (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 159,HAMPTON,VA 23681, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4080-9 PY 1996 BP 119 EP 133 PG 15 WC Computer Science, Artificial Intelligence; Engineering, Multidisciplinary SC Computer Science; Engineering GA BH48G UT WOS:A1996BH48G00008 ER PT J AU Kawahito, K Damm, G Benkowski, R Aber, G Bacak, J Tasai, K Shimono, T Takatani, S Nose, Y Noon, GP DeBakey, ME AF Kawahito, K Damm, G Benkowski, R Aber, G Bacak, J Tasai, K Shimono, T Takatani, S Nose, Y Noon, GP DeBakey, ME TI Ex vivo phase 1 evaluation of the DeBakey NASA axial flow ventricular assist device SO ARTIFICIAL ORGANS LA English DT Article DE axial flow pump; ventricular assist device; thrombus ID PUMP; EXPERIENCE AB A small ventricular assist device intended for long-term implantation has been developed by a cooperative effort between the Baylor College of Medicine and the NASA/Johnson Space Center. To date, in vitro tests have been performed to address hemolysis and pump performance issues. In this Phase 1 study, we assessed the durability and atraumatic features aiming for 2 day implantation. Eight pumps were implanted in 2 calves as paracorporeal left ventricular assist devices. The pump running times ranged from 18 to 203 h (78.1 +/- 23.7; mean +/- SEM). All the pump implantations were terminated because of thrombus formation. Plasma-free hemoglobin levels were below 13.7 mg/dl, except for 1 case complicated by inflow cannula obstruction. The pump speed was maintained between 10,100 and 11,400 rpm. Pump outputs were from 3.6 to 5.2 L/min. The electrical power required by the system ranged between 9 and 12 W. Clinically there was no detectable organ dysfunction noted, and postmortem evaluation demonstrated no pump related adverse effects in either calf except for small kidney infarctions. Thrombus deposition was observed mainly at the hub portions and the now straightener. C1 BAYLOR COLL MED,DEPT SURG,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 28 TC 12 Z9 14 U1 0 U2 1 PU BLACKWELL SCIENCE INC PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0160-564X J9 ARTIF ORGANS JI Artif. Organs PD JAN PY 1996 VL 20 IS 1 BP 47 EP 52 DI 10.1111/j.1525-1594.1996.tb04417.x PG 6 WC Engineering, Biomedical; Transplantation SC Engineering; Transplantation GA TR858 UT WOS:A1996TR85800008 PM 8645129 ER PT B AU Heun, MK Dunn, WE AF Heun, MK Dunn, WE GP ASHRAE TI Principles of refrigerant circuiting with application to microchannel condensers .1. Problem formulation and the effects of port diameter and port shape SO ASHRAE TRANSACTIONS 1996, VOL 102, PT 2 SE ASHRAE TRANSACTIONS LA English DT Proceedings Paper CT 1996 Annual Meeting of the American-Society-of-Heating-Refrigerating-and-Air-Conditioning-Engineers , Inc CY 1996 CL SAN ANTONIO, TX SP Amer Soc Heating Refrigerating & Air Conditioning Engineers AB The growing demand for compact heat exchangers has led to the development of new techniques for size and weight reduction. Recent advances in extrusion and brazing processes have catalyzed the development of microchannel heat exchangers, one type of compact heat exchanger Because the microchannel heat exchanger technology is relatively new a need exists for (a) systematic evaluation of the factors that influence refrigerant circuiting design and (b) development of principles for use in refrigerant circuiting design. In this paper the authors formulate refrigerant circuiting design issues in terms of an optimization problem where the objective is minimization of heat exchanger volume per unit heat transfer A systems viewpoint is taken wherein appropriate constraints on heat exchanger duty and refrigerant-side pressure drop are selected to ensure that each refrigerant circuiting option provides equivalent system behavior In part I of this paper we examine the effects of tube diameter and tube shape on refrigerant circuiting design. A single-phase heat exchanger analysis is performed, showing that smaller tube diameters (a) reduce heat exchanger internal volume; (b) require additional, parallel refrigerant passages; and (c) require reduced refrigerant tube length. The analysis shows that port shape has a significant impact on heat exchanger volume and refrigerant circuiting. Noncircular ports are shown to yield smaller external heat exchanger volume, while circular ports provide smaller heat exchanger internal volume. Notably proper design of refrigerant circuiting is the key to heat exchanger volume reduction. Finally, we show that the results of the single-phase heat exchanger analysis are applicable to two-phase situations if convective effects are dominant (e.g., annular flow condensation and convective boiling). In part II, we evaluate the effect of refrigerant circuiting in a microchannel condenser and evaluate the extendability of the single-phase heat exchanger analysis presented in part I. RP Heun, MK (reprint author), CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 2 U1 0 U2 0 PU AMER SOC HEATING, REFRIGERATING AND AIR-CONDITIONING ENGS PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 J9 ASHRAE TRAN PY 1996 VL 102 BP 373 EP 381 PN 2 PG 9 WC Construction & Building Technology; Engineering, Mechanical SC Construction & Building Technology; Engineering GA BG87V UT WOS:A1996BG87V00041 ER PT B AU Heun, MK Dunn, WE AF Heun, MK Dunn, WE GP ASHRAE TI Principles of refrigerant circuiting with application to microchannel condensers .2. The pressure-drop effect and the cross-flow heat exchanger effect SO ASHRAE TRANSACTIONS 1996, VOL 102, PT 2 SE ASHRAE TRANSACTIONS LA English DT Proceedings Paper CT 1996 Annual Meeting of the American-Society-of-Heating-Refrigerating-and-Air-Conditioning-Engineers , Inc CY 1996 CL SAN ANTONIO, TX SP Amer Soc Heating Refrigerating & Air Conditioning Engineers AB This paper analyzes refrigerant circuiting design in two-phase heat exchangers. In particular, we study a new type of compact heat exchanger, the microchannel heat exchanger. In addition to port size and port shape effects, the pressure-drop effect and the cross-flow heat exchanger effect are considered. We find that, as expected, refrigerant circuiting design principles obtained from the single-phase heat exchanger analysis presented in part I are applicable to two-phase heat exchangers. In addition, we find that for a given port diameter, the pressure-drop effect provides an optimum relationship between the number of parallel refrigerant passages and the heat exchanger length. We also find that the cross-flow heat exchanger effect interacts with the pressure-drop effect, particularly when the condenser face area is constrained. There exists an optimum combination of the number of ports and the number of tubes that minimizes condenser volume for a given port diameter. RP Heun, MK (reprint author), CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 2 U1 0 U2 0 PU AMER SOC HEATING, REFRIGERATING AND AIR-CONDITIONING ENGS PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 J9 ASHRAE TRAN PY 1996 VL 102 BP 382 EP 393 PN 2 PG 12 WC Construction & Building Technology; Engineering, Mechanical SC Construction & Building Technology; Engineering GA BG87V UT WOS:A1996BG87V00042 ER PT J AU Dellacorte, C Laskowski, JA AF Dellacorte, C Laskowski, JA GP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS TI Tribological evaluation of PS300: A new chrome oxide-based solid lubricant coating sliding against Al2O3 from 25 degrees to 650 degrees C SO ASME/STLE TRIBOLOGY CONFERENCE, 1996 LA English DT Proceedings Paper CT ASME/STLE 1996 Tribology Conference CY OCT 13-17, 1996 CL SAN FRANCISCO, CA SP ASME, STLE DE tribology; friction; wear; ceramics; high temperature; solid lubricants; surface films coatings C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44195. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068-2376 PY 1996 BP 183 EP 187 PG 5 WC Engineering, Mechanical SC Engineering GA BG54X UT WOS:A1996BG54X00024 ER PT S AU Byrnes, DV Bright, LE AF Byrnes, DV Bright, LE BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Design of high-accuracy multiple flyby trajectories using constrained optimization SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 121 EP 133 PN 1&2 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00008 ER PT S AU Thurman, SW Flasher, H AF Thurman, SW Flasher, H BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI A conceptual automatic landing system for spacecraft using pulse-modulated propulsion SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 135 EP 152 PN 1&2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00009 ER PT S AU Nerem, RS Lerch, FJ Salman, R Trimmer, R Kenyon, S Rapp, RH Pavlis, NK Klosko, SM Chan, JC Torrence, MH Wang, YM Williamson, RG Pavlis, EC AF Nerem, RS Lerch, FJ Salman, R Trimmer, R Kenyon, S Rapp, RH Pavlis, NK Klosko, SM Chan, JC Torrence, MH Wang, YM Williamson, RG Pavlis, EC BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Preliminary results from the joint GSFC/DMA gravity model project SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 163 EP 182 PN 1&2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00011 ER PT S AU Marshall, JA Lemoine, FG Luthcke, SB Chan, JC Cox, CM Rowton, SC Williamson, RG Wiser, JL AF Marshall, JA Lemoine, FG Luthcke, SB Chan, JC Cox, CM Rowton, SC Williamson, RG Wiser, JL BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Precision orbit determination and gravity field improvement derived from TDRS SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,LAB TERR PHYS,GREENBELT,MD 20771. RI Luthcke, Scott/D-6283-2012; Lemoine, Frank/D-1215-2013 NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 183 EP 200 PN 1&2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00012 ER PT S AU Lemoine, FG Smith, DE Zuber, MT Rowlands, DD Neumann, GA AF Lemoine, FG Smith, DE Zuber, MT Rowlands, DD Neumann, GA BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Results from the Clementine lunar geodesy investigation SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,LAB TERR PHYS,GREENBELT,MD 20771. RI Rowlands, David/D-2751-2012; Lemoine, Frank/D-1215-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 201 EP 223 PN 1&2 PG 23 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00013 ER PT S AU Vijayarahavan, A AF Vijayarahavan, A BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Mars gravity field from satellite-to-satellite Doppler data SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,NAVIGAT & FLIGHT MECH SECT,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 225 EP 238 PN 1&2 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00014 ER PT S AU Byrnes, DV DAmario, LA AF Byrnes, DV DAmario, LA BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Dactyl orbit determination analysis SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 239 EP 248 PN 1&2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00015 ER PT S AU Smith, JC Garner, G AF Smith, JC Garner, G BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Satellite tour design at Saturn using an Excel spreadsheet SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 383 EP 406 PN 1&2 PG 24 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00024 ER PT S AU Newman, LK Folta, DC AF Newman, LK Folta, DC BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Evaluation of spacecraft end-of-life disposal to meet NASA management instruction (NMI) guidelines SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,FLIGHT DYNAM DIV,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 407 EP 426 PN 1&2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00025 ER PT S AU Hastrup, R McOmber, R Nelson, K AF Hastrup, R McOmber, R Nelson, K BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Relay satellite orbit selection considerations for future robotics missions to explore Venus SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,MISSION DESIGN SECT,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 427 EP 442 PN 1&2 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00026 ER PT S AU Harrison, EF Wielicki, BA Gibson, GG Denn, FM AF Harrison, EF Wielicki, BA Gibson, GG Denn, FM BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Orbital analysis of LidarSat for synergistic measurements with the Earth Observing System (EOS) satellite SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,RADIAT SCI BRANCH,HAMPTON,VA 23681. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 475 EP 480 PN 1&2 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00029 ER PT S AU LeeGlauser, GJ Juang, JN Longman, RW AF LeeGlauser, GJ Juang, JN Longman, RW BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Comparison and combination of learning controllers: Computational enhancement and experiments SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 629 EP 647 PN 1&2 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00040 ER PT S AU Frauenholz, RB Bhat, RS Shapiro, BE AF Frauenholz, RB Bhat, RS Shapiro, BE BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI An analysis of the TOPEX/Poseidon operational orbit: Observed variations and why SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1127 EP 1144 PN 1&2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00071 ER PT S AU Kangas, J Salama, A AF Kangas, J Salama, A BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Statistical performance of TOPEX/Poseidon prime mission ground and on-board ephemerides and consequences for the extended mission SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1145 EP 1159 PN 1&2 PG 15 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00072 ER PT S AU Cangahuala, LA Muellerschoen, RJ Yuan, DN Christensen, EJ Graat, EJ Guinn, JR AF Cangahuala, LA Muellerschoen, RJ Yuan, DN Christensen, EJ Graat, EJ Guinn, JR BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI TOPEX/Poseidon precision orbit determination: ''Quick-look'' operations with SLR and GPS data SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,NAVIGAT SYST SECT,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1161 EP 1172 PN 1&2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00073 ER PT S AU Haines, BJ Lichten, SM Srinivasan, JM Kelecy, TM LaMance, JW AF Haines, BJ Lichten, SM Srinivasan, JM Kelecy, TM LaMance, JW BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI GPS-like tracking of geosynchronous satellites: Orbit determination results for TDRS and Inmarsat SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1225 EP 1242 PN 1&2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00077 ER PT S AU Bhaskaran, S Riedel, JE Synnott, SP AF Bhaskaran, S Riedel, JE Synnott, SP BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Demonstration of autonomous orbit determination around small bodies SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,NAVIGAT & FLIGHT MECH SECT,PASADENA,CA 91109. NR 0 TC 0 Z9 3 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1297 EP 1308 PN 1&2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00081 ER PT S AU Spencer, DA Braun, RD AF Spencer, DA Braun, RD BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Mars pathfinder atmospheric entry trajectory design SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,NAVIGAT & FLIGHT MECH SECT,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1353 EP 1370 PN 1&2 PG 18 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00084 ER PT S AU Bender, DF Penzo, PA AF Bender, DF Penzo, PA BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Multiple encounter missions with the Trojan and main belt asteroids SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,MISSIONS & SYST ARCHITECTURE SECT,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1371 EP 1386 PN 1&2 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00085 ER PT S AU DAmario, LA Byrnes, DV Haw, RJ Kirhofer, WE Nicholson, FT Wilson, MG AF DAmario, LA Byrnes, DV Haw, RJ Kirhofer, WE Nicholson, FT Wilson, MG BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Navigation strategy for the Galileo Jupiter encounter and orbital tour SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1387 EP 1411 PN 1&2 PG 25 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00086 ER PT S AU Wolf, AA Seal, DA AF Wolf, AA Seal, DA BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Exposure of the Cassini spacecraft to horseshoe and tadpole particle zones SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,CASSINI MISSION DESIGN,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1413 EP 1432 PN 1&2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00087 ER PT S AU Vaughan, RM Synnott, SP AF Vaughan, RM Synnott, SP BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Autonomous optical navigation for the Pluto fast flyby mission SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1433 EP 1449 PN 1&2 PG 17 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00088 ER PT S AU Lee, AY AF Lee, AY BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI A component model reduction methodology for multi-flexible body spacecraft SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1509 EP 1522 PN 1&2 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00092 ER PT S AU Sweetser, TH AF Sweetser, TH BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Several ways to leave for luna SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Meeting Abstract CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1681 EP 1681 PN 1&2 PG 1 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00102 ER PT S AU Salama, A Kangas, J AF Salama, A Kangas, J BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Semi-autonomous spacecraft on-board ephemeris propagation SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1731 EP 1744 PN 1&2 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00106 ER PT S AU Crouse, P Lewis, M AF Crouse, P Lewis, M BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI A feasibility study of high lift to drag vehicles for aerocapture SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,FLIGHT DYNAM DIV,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1829 EP 1847 PN 1&2 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00112 ER PT S AU Powers, PP Cappellari, JO March, L Lynch, JP Marr, GC AF Powers, PP Cappellari, JO March, L Lynch, JP Marr, GC BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Goddard Space Flight Center Flight Dynamics Division ascent acquisition support of space shuttle rendezvous missions SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 1989 EP 2007 PN 1&2 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00120 ER PT S AU Cieslak, CJ Good, SM Cox, EL Harrington, TL AF Cieslak, CJ Good, SM Cox, EL Harrington, TL BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Operational maneuver support for low earth-orbiting spacecraft at the Goddard Space Flight Center flight dynamics division SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 2009 EP 2024 PN 1&2 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00121 ER PT S AU Jackson, JA Marr, GC Maher, MJ AF Jackson, JA Marr, GC Maher, MJ BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Tracking and data relay satellite system (TDRSS) support of user spacecraft without TDRSS transponders SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,DIV FLIGHT DYNAM,VEHICLE & NETWORK SECT,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 2025 EP 2043 PN 1&2 PG 19 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00122 ER PT S AU Richon, KV Newman, LK AF Richon, KV Newman, LK BE Alfriend, KT Ross, IM Misra, AK Peters, CF TI Flight dynamics support for the Clementine deep space program science experiment (DSPSE) mission SO ASTRODYNAMICS 1995 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Conference CY FEB 14-17, 1995 CL HALIFAX, CANADA SP Amer Astron Soc, Amer Inst Aeronaut & Astronaut C1 NASA,GODDARD SPACE FLIGHT CTR,DIV FLIGHT DYNAM,CLEMENTINE PROJECT,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 SN 0065-3438 BN 0-87703-407-9 J9 ADV ASTRONAUT SCI PY 1996 VL 90 BP 2045 EP 2064 PN 1&2 PG 20 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BF21S UT WOS:A1996BF21S00123 ER PT B AU Arnaud, KA AF Arnaud, KA BE Jacoby, GH Barnes, J TI XSPEC: The first ten years SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 2834 Z9 2837 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 17 EP 20 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00003 ER PT B AU Boden, AF Redding, DC Hanisch, RJ AF Boden, AF Redding, DC Hanisch, RJ BE Jacoby, GH Barnes, J TI Massively parallel spatially-variant maximum likelihood image restoration SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 131 EP 134 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00029 ER PT J AU Howard, S AF Howard, S BE Jacoby, GH Barnes, J TI The changing scene at NASA Headquarters SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 NASA HEADQUARTERS,OFF SPACE SCI,WASHINGTON,DC 20546. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 459 EP 462 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00101 ER PT J AU Johnson, E Antunes, A AF Johnson, E Antunes, A BE Jacoby, GH Barnes, J TI A high capacity Object Oriented Mission scheduling system for XTE SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 463 EP 466 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00102 ER PT B AU Klinglesmith, DA Sonneborn, G Polidan, RS Thompson, RW Taylor, LL Carini, MT Lawton, PJ VanSteenberg, ME AF Klinglesmith, DA Sonneborn, G Polidan, RS Thompson, RW Taylor, LL Carini, MT Lawton, PJ VanSteenberg, ME BE Jacoby, GH Barnes, J TI Availability of Copernicus UV data in FITS format SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 521 EP 524 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00114 ER PT J AU Oliversen, NA Lawton, PJ VanSteenberg, ME AF Oliversen, NA Lawton, PJ VanSteenberg, ME BE Jacoby, GH Barnes, J TI WISARD: A Web Interface for Searching Archival Research Data SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 GODDARD SPACE FLIGHT CTR,HUGHES STX,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 2 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 528 EP 531 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00116 ER PT J AU Rots, AH AF Rots, AH BE Jacoby, GH Barnes, J TI The XTE FITS database (XFDB) SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 GODDARD SPACE FLIGHT CTR,XTE GUEST OBSERVER FACIL,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 540 EP 543 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00119 ER PT B AU Calvo, SC White, NE McGlynn, TA Duesterhaus, MM Rosen, CA Sabol, EJ AF Calvo, SC White, NE McGlynn, TA Duesterhaus, MM Rosen, CA Sabol, EJ BE Jacoby, GH Barnes, J TI An enriched meta-information schema for astronomical databases SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS V SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 5th Annual Conference on Astronomical Data Analysis Software and Systems (ADASS V) CY OCT 22-25, 1995 CL NATL OPT ASTRON OBSERVATORIES, TUCSON, AZ SP Infrared Proc & Anal Ctr, Int Gemini 8 Meter Telescopes Project, NASA, Natl Opt Astron Observatories, Natl Radio Astron Observatory, Natl Res Council Canada, Smithsonian Astrophys Observatory, Space Telescope Sci Inst, Univ Arizona Steward Observatory, Vatican Observatory, Co Comp Inc, Network Comp Devices Inc, Sun Microsystems Inc, Res Syst Inc HO NATL OPT ASTRON OBSERVATORIES C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 J9 ASTR SOC P PY 1996 VL 101 BP 566 EP 568 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BG37A UT WOS:A1996BG37A00124 ER PT J AU Dewey, RJ Ojeda, MJ Gwinn, CR Jones, DL Davis, MM AF Dewey, RJ Ojeda, MJ Gwinn, CR Jones, DL Davis, MM TI VLBI astrometry of the millisecond pulsar B1937+21 SO ASTRONOMICAL JOURNAL LA English DT Article ID RADIO INTERFEROMETRY AB We report the results of astrometric VLBI observations of PSR B1937+21. Observations of the pulsar and a nearby quasar were made at 1.67 GHz, using four antennas: Arecibo, the very large array, and the DSN 70 m antennas in California and Spain. We determine a position of alpha=19(h)39(m)38(s).5611+/-0(S).0003 and delta=21 degrees 34'59''.118+/-0''.016 for the pulsar in the IERS extragalactic reference frame at epoch 1990.2. The accuracy of our result in right ascension is limited by systematic uncertainties in the ionospheric delay calibration, and larger-than-expected random scatter in the pulsar delays related to interstellar scintillation. The accuracy in declination is limited by the lack of a long north-south baseline in our experiment and the uncertainty of the location of the Arecibo antenna in the IERS celestial reference frame. When compared with the pulsar's timing position [Kaspi, et al., ApJ, 428, 713 (1994)] in the planetary ephemeris reference frame, our result yields a measurement of the offset of the IERS reference frame and the DE200 planetary ephemeris frame of Delta alpha((IERS-DE200))=0(s).0008+/-0(s).0003 and Delta delta((IERS-DE200))=-0''.024+/-0''.016, which is in reasonable agreement with the frame-tie rotation determined by Folkner et al. [ARA&A, 297, 279, (1994)]. (C) 1996 American Astronomical Society. C1 UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. CALTECH,JET PROP LAB,PASADENA,CA 91125. NATL ASTRON & IONOSPHERE CTR,ARECIBO,PR 00613. RP Dewey, RJ (reprint author), PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544, USA. NR 18 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 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 1996 VL 111 IS 1 BP 315 EP 319 DI 10.1086/117783 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN578 UT WOS:A1996TN57800029 ER PT J AU BeckWinchatz, B Bohm, KH NoriegaCrespo, A AF BeckWinchatz, B Bohm, KH NoriegaCrespo, A TI The gas-phase abundances of heavy elements and the destruction of dust grains in Herbig-Haro shock waves SO ASTRONOMICAL JOURNAL LA English DT Article ID HIGH-RESOLUTION; STELLAR JETS; YOUNG STARS; LONG-SLIT; OBJECTS AB The gas-phase abundance ratios Fe/S and Fe/O have been determined for the Herbig-Haro objects HH 1, HH 7, HH 11, HH 43A, and HH 255 (Burnham's Nebula) from a fairly large number of forbidden emission lines. For HH 1, the ratio Ni/S has been determined as well. Our objective was to investigate whether Fe and Ni are depleted by dust formation in the line-emitting regions as is typical for normal (neutral or molecular) interstellar regions, or whether the observed matter has gone through sufficiently fast shock waves so that the dust grains have been destroyed and Fe and Ni have gone back into the gas phase. Using observationally determined electron temperatures and densities we have solved the statistical equilibrium equations for Fe+, Fe++, S+, O-0, O+, O++, and Ni+ and calculated the intensities of the respective emissions lines. For Fe+ a large number of new collision strengths has recently become available which enabled us to include a much greater number of transitions in our calculations than has previously been possible. For HH 1 and HH 7 both ratios Fe/S and Fe/O agree very well with the solar abundance ratios. For HH 11, the more reliable ratio Fe/S is also very close to the solar value, while the less reliable ratio Fe/O is somewhat higher. For HH 43A both abundance ratios suggest an Fe depletion by a factor 2-3 but the result is considered somewhat uncertain. The results for Burnham's Nebula also indicate a depletion of Fe (by a factor of similar to 3) and are more reliable. We conclude that this object has undergone a dust formation and shock wave history which is quite different from that of HH 1, HH 7, and HH 11. The Ni/S abundance ratio determined for HH 1 is a factor similar to 10 larger than the solar value. The results for the different observed [Ni II] lines are quite consistent. This situation has been found in other gaseous nebulae as well and is still enigmatic. (C) 1996 American Astronomical Society. C1 CALTECH, JET PROP LAB, INFRARED PROC & DATA ANAL CTR, PASADENA, CA 91125 USA. RP BeckWinchatz, B (reprint author), UNIV WASHINGTON, DEPT ASTRON, BOX 351580, SEATTLE, WA 98195 USA. NR 44 TC 23 Z9 23 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 1996 VL 111 IS 1 BP 346 EP 354 DI 10.1086/117787 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TN578 UT WOS:A1996TN57800033 ER PT J AU Soltan, AM Hasinger, G Egger, R Snowden, S Trumper, J AF Soltan, AM Hasinger, G Egger, R Snowden, S Trumper, J TI The large scale structure of the soft X-ray background .1. Clusters of galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE cosmology, observations, diffuse radiation; X-rays, galaxies; X-rays, general; galaxies, clusters of ID ROSAT PSPC; ENERGY-SPECTRA; DIFFUSE; ABELL; GAS AB Large-scale fluctuations of the X-ray background are investigated using the ROSAT All-Sky Survey. The autocorrelation function of the extragalactic background at similar to 1 keV is determined at separations 0 degrees 1. < theta < 40 degrees. We detect a significant signal for theta < 6 degrees, which is larger than previous upper limits. We analyse the cross-correlation between the angular positions of Abell clusters of galaxies and the intensity of the X-ray background. The cross-correlation extends to several degrees for clusters of distance class less than or equal to 4. We conclude that Abell clusters are associated with extended, low surface brightness X-ray haloes. The mean luminosity of the diffuse sources in the 0.5 - 2.0 keV band is L approximate to 2.5 x 10(43) h(-2) ergs(-1) and their char acteristic radius a approximate to 10 h(-1) Mpc (H-0 = 100 h km s(-1) Mpc(-1)). It is shown that the higher density of normal galaxies and AGNs around clusters cannot be responsible for the increased X-ray emission. This is because it would produce a signal in the autocorrelation function measurable by the Ginga LAC experiment. Apparent extended emission could be produced either by a number of discrete sources associated with groups of galaxies concentrated around rich clusters or by a hot diffuse gas. It is shown that sources associated with Abell clusters account for similar to 30% of the X-ray background fluctuations on scales above similar to 1 degrees. C1 MAX PLANCK INST EXTRATERR PHYS, D-85748 GARCHING, GERMANY. INST ASTROPHYS, D-14482 POTSDAM, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, LHEA, GREENBELT, MD 20771 USA. RP Soltan, AM (reprint author), COPERNICUS ASTRON CTR, BARTYCKA 18, PL-00716 WARSAW, POLAND. RI Snowden, Steven/D-5292-2012 NR 39 TC 49 Z9 48 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 JAN 1 PY 1996 VL 305 IS 1 BP 17 EP 32 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM488 UT WOS:A1996TM48800002 ER PT J AU Puls, J Kudritzki, RP Herrero, A Pauldrach, AWA Haser, SM Lennon, DJ Gabler, R Voels, SA Vilchez, JM Wachter, S Feldmeier, A AF Puls, J Kudritzki, RP Herrero, A Pauldrach, AWA Haser, SM Lennon, DJ Gabler, R Voels, SA Vilchez, JM Wachter, S Feldmeier, A TI O-star mass-loss and wind momentum rates in the Galaxy and the Magellanic Clouds SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE line, formation; stars, atmospheres; stars, distances; stars, early-type; stars, mass-loss; Magellanic Clouds ID RADIATION-DRIVEN WINDS; HOT LUMINOUS STARS; INCLUDING SPHERICAL EXTENSION; TIME-SERIES OBSERVATIONS; H-ALPHA EMISSION; NON-LTE ANALYSIS; STELLAR WINDS; EXPANDING ATMOSPHERES; SOBOLEV APPROXIMATION; IUE OBSERVATIONS AB A new, very fast approximate method is presented to determine mass-loss rates of O-stars from H-alpha line profiles. The method uses H and HeII departure coefficients from unified model atmospheres parametrized in a simple way as function of wind velocity together with photospheric NLTE line profiles as the inner boundary condition for a numerically exact radiative transfer solution to derive a wind contaminated H-alpha -profile. The method is also applied to H-gamma to determine stellar gravities corrected for wind emission. A detailed analytical discussion of H-alpha line formation in O-star winds is given and it is demonstrated that former very simple approaches considering only optically thin wind emission lead to significant systematic errors. Scaling relations and generalized curves of growth are presented that connect mass-loss rate, terminal velocity, stellar parameters and H-alpha equivalent width. The method is applied to samples of O-stars in the Galaxy, LMC and SMC and mass-loss rates are derived from H-alpha in combination with terminal velocities measured from IUE and HST spectra. The results reveal that a tight empirical relation exists between the radius modified stellar wind momentum rate M v(infinity)R*(0.5) and the stellar luminosity. The variations of this relationship between the Galaxy, LMC and SMC are explained in terms of different abundances. Furthermore, for almost all objects with dense winds (mostly supergiants), the commonly used velocity field exponent beta could be derived, indicating a typical value of beta approximate to 1. A comparison with the improved theory of radiation driven winds (as presented recently by Pauldrach et al. 1994) shows that the observed wind momentum-luminosity relationship can be understood qualitatively in terms of the theory. However, there exist significant systematic discrepancies as a function of effective temperature, luminosity class and wind performance number eta = M v(infinity)c/L. We stress that these discrepancies would not have been detected with previous simplified H-alpha-approaches. The deficiencies of the theory are discussed and suggestions for future improvements are made. C1 MAX PLANCK INST ASTROPHYS, D-85740 GARCHING, GERMANY. IAC, INST ASTROFIS CANARIAS, San Cristobal la Laguna, SPAIN. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV WASHINGTON, DEPT ASTRON, SEATTLE, WA 98195 USA. RP Puls, J (reprint author), UNIV STERNWARTE MUNCHEN, SCHEINERSTR 1, D-81679 MUNICH, GERMANY. OI Vilchez, J. M./0000-0001-7299-8373 NR 85 TC 360 Z9 361 U1 0 U2 1 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 JAN 1 PY 1996 VL 305 IS 1 BP 171 EP 208 PG 38 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM488 UT WOS:A1996TM48800015 ER PT J AU Malbet, F AF Malbet, F TI High angular resolution coronography for adaptive optics SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE instrumentation, miscellaneous; techniques, miscellaneous; stars, imaging; atmospheric effects ID PICTORIS CIRCUMSTELLAR DISK; BETA-PICTORIS; BROAD-BAND; AG CARINAE; NEBULA; TELESCOPE; CORONAGRAPHY; ENVIRONMENT; PLANETS; BIPOLAR AB Recent adaptive optics systems in astronomy achieve high-angular resolution. With the extreme stability of the images, detection at very low fluxes can be reached using a coronograph at the diffraction limit of the telescopes. This paper is an overview of the issues of stellar coronography used at the diffraction limit. Image formation through such a system is illustrated by numerical simulations. The description of a coronograph implemented on the VLT adaptive optics prototype, COME-ON, is presented as well as the first observations. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Malbet, F (reprint author), OBSERV GRENOBLE,ASTROPHYS LAB,BP 53,F-38041 GRENOBLE 9,FRANCE. NR 46 TC 51 Z9 51 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD JAN PY 1996 VL 115 IS 1 BP 161 EP 174 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TP963 UT WOS:A1996TP96300011 ER PT S AU Waga, I Torres, LFB AF Waga, I Torres, LFB BE Kochanek, CS Hewitt, JN TI Vacuum decaying cosmological models and gravitational lensing SO ASTROPHYSICAL APPLICATIONS OF GRAVITATIONAL LENSING SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 173rd Symposium of the International-Astronomical-Union on Astrophysical Applications of Gravitational Lensing CY JUL 09-14, 1995 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP IAU Commiss 47, IAU Commiss 40 HO UNIV MELBOURNE C1 UNIV FED RIO DE JANEIRO,INST FIS,BR-21943 RIO JANEIRO,RJ,BRAZIL. RP Waga, I (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. RI Waga, Ioav/B-6288-2014 NR 6 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-3954-1 J9 IAU SYMP PY 1996 IS 173 BP 23 EP 24 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BF25F UT WOS:A1996BF25F00005 ER PT S AU Surpi, GC Harari, DD Frieman, JA AF Surpi, GC Harari, DD Frieman, JA BE Kochanek, CS Hewitt, JN TI Effects of large-scale structure upon the determination of H-o from time delays SO ASTROPHYSICAL APPLICATIONS OF GRAVITATIONAL LENSING SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 173rd Symposium of the International-Astronomical-Union on Astrophysical Applications of Gravitational Lensing CY JUL 09-14, 1995 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP IAU Commiss 47, IAU Commiss 40 HO UNIV MELBOURNE AB We have analyzed the effects of both large-scale inhomogeneities in the mass distribution and cosmological gravitational waves upon the time delay between two images in a gravitational lens system. We have shown that their leading order effect, which could potentially bias the determination of the Hubble parameter, is indistinguishable from a change in the relative angle between the source and the lens axis. Since the absolute angular position of the source is not directly measurable, nor does it enter the relationship between the Hubble parameter and the lens observables, the determination of H-0 from gravitational lens time delays follows in the usual way, as if the metric perturbations were absent. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Surpi, GC (reprint author), UNIV BUENOS AIRES,FAC CIENCIAS EXACTAS & NAT,DEPT FIS,CIUDAD UNIV PAB 1,RA-1428 BUENOS AIRES,DF,ARGENTINA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-3954-1 J9 IAU SYMP PY 1996 IS 173 BP 91 EP 92 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BF25F UT WOS:A1996BF25F00022 ER PT S AU Michalitsianos, AG Oliversen, RJ AF Michalitsianos, AG Oliversen, RJ BE Kochanek, CS Hewitt, JN TI Far-UV spectral variability in UM425 & PG1115+080 SO ASTROPHYSICAL APPLICATIONS OF GRAVITATIONAL LENSING SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 173rd Symposium of the International-Astronomical-Union on Astrophysical Applications of Gravitational Lensing CY JUL 09-14, 1995 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP IAU Commiss 47, IAU Commiss 40 HO UNIV MELBOURNE RP Michalitsianos, AG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,WASHINGTON,DC 20546, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-3954-1 J9 IAU SYMP PY 1996 IS 173 BP 257 EP 258 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BF25F UT WOS:A1996BF25F00068 ER PT S AU Jones, DL Preston, RA Murphy, DW Meier, DL Jauncey, DL Reynolds, JE Tzioumis, AK AF Jones, DL Preston, RA Murphy, DW Meier, DL Jauncey, DL Reynolds, JE Tzioumis, AK BE Kochanek, CS Hewitt, JN TI Interstellar scattering and the Einstein ring PKS 1830-211 SO ASTROPHYSICAL APPLICATIONS OF GRAVITATIONAL LENSING SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 173rd Symposium of the International-Astronomical-Union on Astrophysical Applications of Gravitational Lensing CY JUL 09-14, 1995 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP IAU Commiss 47, IAU Commiss 40 HO UNIV MELBOURNE AB The remarkably strong radio gravitational lens PKS 1830-211 consists of a one arcsecond diameter Einstein ring with two bright compact components located on opposite sides of the ring. We have obtained 22 GHz VLBA data on this source to determine the intrinsic angular sizes of the compact components. Previous VLBI observations at lower frequencies indicate that the brightness temperatures of these components are significantly lower than 10(10) K (Jauncey et al. 1991), less than is typical for compact synchrotron radio sources and less than is implied by flux density variations. A possible explanation is that interstellar scattering is broadening the apparent angular size of the source and thereby reducing the observed brightness temperature. Our VLBA data support this hypothesis. C1 CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. RP Jones, DL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL CODE 238-332,PASADENA,CA 91109, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-3954-1 J9 IAU SYMP PY 1996 IS 173 BP 345 EP 346 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BF25F UT WOS:A1996BF25F00098 ER PT S AU Wang, Y AF Wang, Y BE Kochanek, CS Hewitt, JN TI The statistics of nearly on-axis gravitational lensing events SO ASTROPHYSICAL APPLICATIONS OF GRAVITATIONAL LENSING SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 173rd Symposium of the International-Astronomical-Union on Astrophysical Applications of Gravitational Lensing CY JUL 09-14, 1995 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP IAU Commiss 47, IAU Commiss 40 HO UNIV MELBOURNE ID LENSES AB A small volume of space, nearly on-axis behind a gravitational lens with respect to a given source, will receive a greatly increased radiation flux. In the idealized case of a point mass lens acting on a point source in complete isolation, the volume will approach zero only as the flux tends to infinity; in fact, the volume weighted rms flux is divergent. In realistic cases, finite source size and the effects of other gravitational deflections (i.e., non-zero shear) limit the maximum flux and consideraly complicate the physics, but very large fluxes are still produced in small volumes. We consider the physics and statistics of these Extreme Gravitational Lensing Events (EGLE) and present an initial examination of their possible astrophysical effects for various known and putative populations of lensing objects and sources, with particular attention to the case in which finite source size is important but shear is not. RP Wang, Y (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. RI Wang, Yun/B-5724-2011 OI Wang, Yun/0000-0002-4749-2984 NR 3 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-3954-1 J9 IAU SYMP PY 1996 IS 173 BP 371 EP 376 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BF25F UT WOS:A1996BF25F00105 ER PT J AU Mulchaey, JS Davis, DS Mushotzky, RF Burstein, D AF Mulchaey, JS Davis, DS Mushotzky, RF Burstein, D TI The intragroup medium in poor groups of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE dark matter; galaxies, clusters, general; galaxies, fundamental parameters; intergalactic medium; X-rays, galaxies ID DARK MATTER; X-RAY; CATALOG; GAS AB We have used the ROSAT PSPC to search for diffuse, extended X-ray emission in a sample of 14 galaxy groups. A diffuse component was found in four cases. Combining our new analysis with published X-ray observations, we found that a total of 48 galaxy groups of varying size and velocity dispersion have analyzed ROSAT X-ray data. Diffuse, approximate to 1.0 keV X-ray gas is seen in 25 of the 48 groups analyzed, but the true incidence of such an intragroup medium is probably lower, since this sample includes X-ray-discovered groups. X-ray luminosity does not correlate well with the optical richness, blue luminosity, or velocity dispersion of the group. In contrast, there is a strong correlation with the percentage of early-type (E and S0) galaxies. All of the groups with an extended intragroup medium have high percentages of early-type galaxies, and over half of these systems appear to contain no spirals at all. Furthermore, all the X-ray-detected systems contain at least one elliptical with a blue luminosity of L(B) similar to 5 x 10(10) L(.) or greater. We discuss several possible explanations for the correlation between spiral fraction and the presence of diffuse hot gas, including the idea that the spiral-rich groups represent superpositions of galaxies, that they contain a relatively cool intragroup medium, or that the formation and evolution of spiral-rich groups are fundamentally different from those of elliptical-rich groups. We also use the X-ray observations to estimate the total masses of these systems. There is a large range in the derived gas masses, but in general the mass in the X-ray-emitting gas is comparable to or less than the mass in the galaxies. Despite the large range in gas mass, there is a very narrow range in total group mass, with most of the groups having a mass of similar to 2 x 10(13) M(.) out to the radius for which X-ray emission is detected by ROSAT. The ratio of observed luminous mass (i.e., galaxies + hot gas) to total inferred mass in poor groups is rather low (approximate to 5%-30%), implying that these systems are dominated by dark matter. C1 UNIV ALABAMA, DEPT PHYS & ASTRON, TUSCALOOSA, AL 35487 USA. NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. RP CARNEGIE INST WASHINGTON OBSERV, 813 SANTA BARBARA ST, PASADENA, CA 91101 USA. NR 40 TC 181 Z9 181 U1 0 U2 0 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 JAN 1 PY 1996 VL 456 IS 1 BP 80 EP 97 DI 10.1086/176629 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM837 UT WOS:A1996TM83700007 ER PT J AU Schlegel, EM Petre, R Colbert, EJM AF Schlegel, EM Petre, R Colbert, EJM TI The X-ray light curve of the very luminous supernova SN 1978k in NGC 1313 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (NGC 1313); pulsars, general; supernovae, individual (SN 1978K); supernova remnants; X-rays, stars ID GAMMA-RAYS; EMISSION; SN-1986J; PULSAR; NOVAE AB We present the 0.5-2.0 keV light curve of the X-ray luminous supernova SN 1978K in NGC 1313, based on six ROSAT observations spanning 1990 July to 1994 July. SN 1978K is one of a few supernovae or supernova remnants that are very luminous (similar to 10(39)-10(40) ergs s(-1)) in the X-ray, optical, and radio bands, and the first, at a supernova age of 10-20 yr, for which sufficient data exist to create an X-ray light curve. The X-ray flux is approximately constant over the 4 yr sampled by our observations, which were obtained 12-16 yr after the initial explosion. Three models exist to explain the large X-ray luminosity: pulsar input, a reverse shock running back into the expanding debris of the supernova, and the outgoing shock crushing of cloudlets in the debris field. Based upon calculations of Chevalier & Fransson, a pulsar cannot provide sufficient energy to produce the soft X-ray luminosity. Based upon the models and the light curve to date, it is not possible to discern the evolutionary phase of the supernova. RP NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. NR 34 TC 27 Z9 27 U1 0 U2 0 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 JAN 1 PY 1996 VL 456 IS 1 BP 187 EP 193 DI 10.1086/176639 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM837 UT WOS:A1996TM83700017 ER PT J AU Hester, JJ Stone, JM Scowen, PA Jun, BI Gallagher, JS Norman, ML Ballester, GE Burrows, CJ Casertano, S Clarke, JT Crisp, D GriffIths, RE Hoessel, JG Holtzman, JA Krist, J Mould, JR Sankrit, R Stapelfeldt, KR Trauger, JT Watson, A Westphal, JA AF Hester, JJ Stone, JM Scowen, PA Jun, BI Gallagher, JS Norman, ML Ballester, GE Burrows, CJ Casertano, S Clarke, JT Crisp, D GriffIths, RE Hoessel, JG Holtzman, JA Krist, J Mould, JR Sankrit, R Stapelfeldt, KR Trauger, JT Watson, A Westphal, JA TI WFPC2 studies of the Crab Nebula .3. Magnetic Rayleigh-Taylor instabilities and the origin of the filaments SO ASTROPHYSICAL JOURNAL LA English DT Article DE instabilities; ISM, individual (Crab Nebula); ISM, structure; radiation mechanisms, nonthermal ID DYNAMICS; WIND AB Recently obtained Hubble Space Telescope WFPC2 images of the Crab Nebula show that the emission-line filaments are dominated by structures that morphologically appear to be the result of magnetic Rayleigh-Taylor (R-T) instabilities at the interface between the pulsar-driven synchrotron nebula and a shell of swept-up ejecta. We replace this morphological argument with a quantitative treatment of the growth rate and characteristic wavelength of such instabilities. Using published data on the rate of expansion of the synchrotron nebula and the density of the ejecta, together with a wavelength for the instability measured from the WFPC2 images, we calculate a magnetic field strength of similar to 540 mu G. This is within a factor of 2 of the canonical minimum energy equipartition held of 300 mu G, and probably closer than that to a more realistic estimate of the held at the edge of the Crab. Comparison of the detailed morphology and ionization structure of the R-T fingers in the Crab with recent magnetohydrodynamical simulations which follow the development of magnetic R-T instabilities into the nonlinear regime is used to establish a sequence of filament properties which are determined by the density of the shell of swept-up ejecta at the edge of the synchrotron nebula. When the density is below a critical value, the interface is stable. For somewhat higher densities R-T instabilities grow, but the field, which becomes aligned along the length of the R-T fingers, is strong enough to prevent the development of secondary Kelvin-Helmholtz (K-H) instabilities as the finger falls through the lighter medium. At higher densities these K-H instabilities develop, but the field is still strong enough to maintain a long streamer-like connection between the head of the filament and the shell. In a few cases, the density of the shell is high enough that the magnetic field is unable to prevent the fragmentation of R-T fingers, and the structure becomes more characteristic of a nonmagnetic R-T instability. The magnetic field is oriented along the length of an R-T finger, so material is free to ''pour'' into the finger from above. In equilibrium, gradients in thermal pressure and effective gravity must balance along field lines. As a result, loss of pressure support in the fingers due to cooling enhances the flow of material into the fingers, ''siphoning'' gas into the finger from above. If an extended remnant of ejecta surrounds the visible extent of the Crab, as has been suggested frequently, then the synchrotron nebula is expanding through this extended remnant, sweeping up ejecta as it goes. R-T instabilities channel this swept-up ejecta into the hierarchy of dense visible filaments. It seems likely that the current system of filaments originated as a result of R-T instabilities as the synchrotron nebula expanded out through more uniformly distributed ejecta. If an extended remnant remains today, then filament formation is an ongoing process. The ionization structure of filaments is also found to change in a systematic way as a function of the relative importance of the magnetic field and the mass density. Filaments which are dominated by the magnetic field are confined by the held and have sharp, well defined edges. Filaments in which the magnetic field is less dominant consist of high-density, low-ionization cores embedded within more extended high-ionization material. This confirms a previous suggestion that variations in magnetic confinement are an important caveat to published interpretations of spectra of Crab filaments. C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. UNIV ILLINOIS,DEPT ASTRON,NATL CTR SUPERCOMP APPLICAT,COMPUTAT ASTROPHYS LAB,URBANA,IL 61801. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. UNIV MICHIGAN,DEPT ATMOSPHER & OCEAN SCI,ANN ARBOR,MI 48109. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. CALTECH,JET PROP LAB,PASADENA,CA 91109. JOHNS HOPKINS UNIV,DEPT ASTRON,BALTIMORE,MD 21218. LOWELL OBSERV,FLAGSTAFF,AZ 86001. AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,WESTON,ACT 2611,AUSTRALIA. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP Hester, JJ (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,BOX 871504,TEMPE,AZ 85287, USA. RI Stapelfeldt, Karl/D-2721-2012; Clarke, John/C-8644-2013 NR 29 TC 96 Z9 96 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1996 VL 456 IS 1 BP 225 EP & DI 10.1086/176643 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM837 UT WOS:A1996TM83700021 ER PT J AU Justtanont, K Skinner, CJ Tielens, AGGM Meixner, M Baas, F AF Justtanont, K Skinner, CJ Tielens, AGGM Meixner, M Baas, F TI Modeling of the dust and gas outflows from OH 26.5+0.6: The superwind SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; infrared, stars; stars, AGB and post-AGB; stars, individual (OH 26.5 + 0.6); stars, mass loss ID MASS-LOSS RATES; ASYMPTOTIC GIANT BRANCH; CIRCUMSTELLAR CO EMISSION; BRIGHT CARBON STARS; OH/IR STARS; IR STARS; EVOLVED STARS; INFRARED-EMISSION; RED GIANTS; ENVELOPES AB We have observed the extreme OH/IR star, OH 26.5+0.6, in the infrared dust continuum and in the submillimeter rotational lines of CO. Mid-infrared images reveal the compact nature of the circumstellar shell (<0.''5). A deep 9.7 mu m absorption feature and an absorption at 18 mu m show that the dust mass-loss rate is very high. However, the low antenna temperatures of CO J = 1-0 and 2-1 lines suggest that the outer part of the circumstellar shell is much more tenuous. In order to resolve this discrepancy, we have observed the J = 3-2 and 4-3 CO rotational transitions. We have developed a model for the circumstellar shell for OH 26.5+0.6 which is consistent with the infrared and submillimeter observations. The dust and gas data are well fitted by a two-shell model, consisting of a dense shell surrounded by a more tenuous shell. The former we identify with the superwind (M = 5.5 x 10(-4) M. yr(-1)), and the latter we identify with mass loss on the asymptotic giant branch (AGB) (M = 10(-6) M. yr(-1)). The transition between the two mass-loss phases is shown to be rather abrupt (Delta t < 150 yr). Depending on the mass of the progenitor, this superwind phase may be the last thermal pulse (for M* < 1.5 M.), or the first of a series of the superwind phases (for up to 8 M.), punctuated by a period of low mass-loss rates, before the star evolves off the AGB. C1 INST ASTROPHYS,F-75014 PARIS,FRANCE. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94581. UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801. LEIDEN OBSERV,2300 RA LEIDEN,NETHERLANDS. JOINT ASTRON CTR,HILO,HI 96720. RP Justtanont, K (reprint author), NASA,AMES RES CTR,MS 245-3,MOFFETT FIELD,CA 94035, USA. OI /0000-0003-1689-9201 NR 58 TC 59 Z9 59 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 JAN 1 PY 1996 VL 456 IS 1 BP 337 EP 349 DI 10.1086/176655 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM837 UT WOS:A1996TM83700033 ER PT J AU Wang, H Gary, DE Zirin, H Nitta, N Schwartz, RA Kosugi, T AF Wang, H Gary, DE Zirin, H Nitta, N Schwartz, RA Kosugi, T TI OVRO, BBSO, BATSE, and Yohkoh observations of a twin solar flare SO ASTROPHYSICAL JOURNAL LA English DT Article DE sun, flares; sun, radio radiation; sun, UV radiation; sun, X-rays, gamma rays ID X-RAY TELESCOPE; A MISSION; RESOLUTION; ELECTRONS; EMISSION; BURSTS AB We present the results of studies on two solar flares that occurred on 1993 February 11: an M1.1 hare at 18:07 UT and an M2.7 flare at 18:31 UT. Our study was based on comprehensive observations by the following observatories: Owens Valley Radio Observatory, which obtains 1-18 GHz microwave images; Big Bear Solar Observatory, which obtains magnetograms, H alpha and He D3 filtergrams; BATSE on board Compton Gamma Ray Observatory, which obtains high-resolution hard X-ray spectra; and the Japanese satellite Yohkoh, which obtains high-resolution soft and hard X-ray images. We find the following. (1) While the optical and hard X-ray emissions are confined to a small loop near the leading spot of the active region for both flares, a large-scale soft X-ray loop connects from the leading to the following spot 160 '' away. In low-frequency microwaves (<4 GHz), sources appear at each end of the big loop, and the source near the following spot (away from the H alpha flare site) dominates at frequencies <2.8 GHz. For both flares, as frequency increases, the source near the leading spot becomes dominant, and the source near the following spot vanishes gradually. (2) As frequency increases, the centroid of the leading microwave source moves progressively downward until it reaches the footpoint at high frequencies. (3) For the M2.7 event, in the compact loop near the leading spot, two footpoints are seen in both soft and hard X-rays. The dominant hard X-ray source has a softer spectrum than the weaker one, suggesting that the weaker one may become dominant at the higher energies (>100 keV) responsible for the microwave emission. The high-frequency microwave emission is better associated with this latter footpoint. (4) The large soft X-ray loop in the M2.7 flare is the postflare loop of the M1.1 hare. This flare is associated with a different compact loop which is 40 '' away from the main hare. (5) For the M2.7 flare, the microwave brightness temperature spectra in the sources at the two ends of the big loop require very different source parameters. The primary source near the leading spot can be explained by nonthermal gyrosynchrotron emission from electrons with a power-law energy index (delta) of 5.3. The same group of electrons can explain the observed BATSE hard X-ray spectra. The low-frequency radio source near the following spot is due to either a thermal component, or a nonthermal component with a steep energy index (delta = 9.4). Based on the available information, we cannot distinguish these two possibilities. C1 CALTECH,BIG BEAR SOLAR OBSERV,PASADENA,CA 91125. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. NASA,GODDARD SPACE FLIGHT CTR,HUGHES SXT,GREENBELT,MD 20771. NATL ASTRON OBSERV JAPAN,MITAKA,TOKYO,JAPAN. RP Wang, H (reprint author), NEW JERSEY INST TECHNOL,DEPT PHYS,NEWARK,NJ 07102, USA. OI Gary, Dale/0000-0003-2520-8396 NR 20 TC 15 Z9 16 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 JAN 1 PY 1996 VL 456 IS 1 BP 403 EP & DI 10.1086/176663 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM837 UT WOS:A1996TM83700041 ER PT J AU Mulchaey, JS Mushotzky, RF Burstein, D Davis, DS AF Mulchaey, JS Mushotzky, RF Burstein, D Davis, DS TI High-ionization quasar absorption lines: A test of the existence of hot gas in spiral-rich groups SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology, observations; galaxies, intergalactic medium; Local Group; quasars, absorption lines; ultraviolet, general ID DARK MATTER; GALAXIES; QSOS AB ROSAT studies of poor groups of galaxies have revealed hot, diffuse gas only in groups dominated by E/SO galaxies. Here we investigate the possibility that a similar, but cooler, component exists in spiral-rich groups and can be detected through absorption in QSO spectra. We find that for the expected temperature, density, and metal abundance of the intragroup medium, various high-ionization lines should be detectable. At T similar to 2 x 10(6) K, O VI, Ne VIII, Mg X, and Si XII lines will be seen. Strong Lyman series lines are also expected. A collisionally ionized gas at these temperatures will not produce much C IV and N V absorption, since it requires a multiphase medium to produce spectra that show all of the above ions. In addition, some lines of sight will likely pass only through the intragroup gas, producing pure ''high-ionization'' absorption systems (i.e., O VI lines without associated C IV and N V lines). Recent Hubble Space Telescope (HST) and Keck observations have revealed the presence of absorption lines with some of the properties we predict for the intragroup medium in spiral-rich groups. The discovery of a hot intragroup medium in spiral-rich groups would have many important consequences for extragalactic astronomy, including the possible pressure confinement of low-ionization absorption-line clouds. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. UNIV ALABAMA, DEPT PHYS & ASTRON, TUSCALOOSA, AL 35487 USA. RP Mulchaey, JS (reprint author), OBSERV CARNEGIE INST WASHINGTON, 813 SANTA BARBARA ST, PASADENA, CA 91101 USA. NR 26 TC 46 Z9 46 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1996 VL 456 IS 1 BP L5 EP L8 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TM838 UT WOS:A1996TM83800002 ER PT J AU Contopoulos, J AF Contopoulos, J TI General axisymmetric magnetohydrodynamic flows: Theory and solutions SO ASTROPHYSICAL LETTERS & COMMUNICATIONS LA English DT Article; Proceedings Paper CT NATO Advanced Study Institute on Solar and Astrophysical Magnetohydrodynamic Flows CY JUN 11-23, 1995 CL IRAKLION, GREECE SP NATO ID ACCRETION DISKS; JETS; WINDS AB We formulate the theory of general axisymmetric, steady-state, non-relativistic, ideal magnetohydrodynamic flows which continuously advect poloidal magnetic flux, and obtain self-similar self-consistent solutions of the equations. This situation might have direct astrophysical applications in accretion-outflow scenaria around compact objects in stellar systems and active galactic nuclei. RP Contopoulos, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0888-6512 J9 ASTROPHYS LETT COMM JI Astrophys. Lett. Comm. PY 1996 VL 34 IS 1-6 BP 269 EP 273 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA VB566 UT WOS:A1996VB56600044 ER PT J AU Woo, R AF Woo, R TI Structure in the solar corona from radio scintillation measurements SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT IAU Colloquium 154 on Solar and Interplanetary Transients CY JAN 23-27, 1995 CL PUNE, INDIA SP IAU Commiss 49, IAU Commiss 10, Indian Natl Comm URSI, Indian Space Res Org, Univ Grants Commiss ID INTERPLANETARY SCINTILLATION; DOPPLER SCINTILLATION; RANGING MEASUREMENTS; WIND TURBULENCE; STREAMERS; EVOLUTION; ULYSSES; SPEED; DEPENDENCE; CYCLE AB Since the 1950s, a wide variety of radio observations based on scattering by electron density fluctuations in the solar wind has provided much of our information on density fluctuations and solar wind speed near the source region of the solar wind. This paper reviews recent progress in the understanding of the nature of these density fluctuations and their relationship to features on the Sun. The results include the first measurements of fine-scale structure within coronal streamers and evidence for structure in solar wind speed in the inner corona. RP Woo, R (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 33 TC 5 Z9 5 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 243 IS 1 BP 97 EP 104 DI 10.1007/BF00644038 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XH625 UT WOS:A1996XH62500015 ER PT J AU Thejappa, G Stone, RG Goldstein, ML AF Thejappa, G Stone, RG Goldstein, ML TI Detection of Langmuir solitons: Implications for type III burst emission mechanisms at 2 omega(PE) SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT IAU Colloquium 154 on Solar and Interplanetary Transients CY JAN 23-27, 1995 CL PUNE, INDIA SP IAU Commiss 49, IAU Commiss 10, Indian Natl Comm URSI, Indian Space Res Org, Univ Grants Commiss DE Langmuir solitons; type III bursts ID SOLAR RADIO-BURSTS; WAVES; PLASMA AB We present the experimental verification of existing theoretical models of emission mechanisms of solar type III bursts at the second harmonic of the plasma frequency, omega(pe). This study is based on the detection of Langmuir and envelope solitons by the Ulysses spacecraft inside three type III burst source regions. We show that the oscillating-two-stream instability, coherent radiation by Langmuir solitons and stochastic phase mixing of the Langmuir waves in the strong turbulence regime are the appropriate emission mechanisms at 2 omega(pe). C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. RP Thejappa, G (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Goldstein, Melvyn/B-1724-2008 NR 17 TC 7 Z9 7 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 243 IS 1 BP 195 EP 198 DI 10.1007/BF00644054 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XH625 UT WOS:A1996XH62500031 ER PT J AU Shull, JM Thronson, HA Stern, SA AF Shull, JM Thronson, HA Stern, SA TI Special issue: The search for extra-solar terrestrial planets: Techniques and technology - Proceeds of a conference held in Boulder, Colorado, May 14-17, 1995 - Preface SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Editorial Material C1 UNIV WYOMING,LARAMIE,WY 82071. NASA HEADQUARTERS,CODE SR,WASHINGTON,DC 20546. SW RES INST,BOULDER,CO. RP Shull, JM (reprint author), UNIV COLORADO,DEPT ASTROPHYS PLANETARY & ATMOSPHER SCI,BOULDER,CO 80309, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 241 IS 1 BP 1 EP 2 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WR628 UT WOS:A1996WR62800001 ER PT J AU Shao, M AF Shao, M TI Astrometric detection of Earth-like planets with OSI SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Conference on the Search for Extra-Solar Terrestrial Planets: Techniques and Technology CY MAY 14-17, 1995 CL BOULDER, CO AB The Orbiting Stellar Interferometer (OSI) is a space-based astrometric interferometer designed primarily for wide-angle astrometry. OSI is potentially capable of achieving astrometric accuracies of similar to 1 mu as in narrow angle (1 degrees) astrometry. This paper discusses the implications for astrometric planet detection, specifically the detection of Earth-like planets around nearby stars. OSI has the potential to detect a limited number of planetary systems with Earths, if a number of technical problems are solved. RP Shao, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 241 IS 1 BP 85 EP 88 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WR628 UT WOS:A1996WR62800008 ER PT J AU Shao, M AF Shao, M TI Ground-based interferometry SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Conference on the Search for Extra-Solar Terrestrial Planets: Techniques and Technology CY MAY 14-17, 1995 CL BOULDER, CO ID ADAPTIVE OPTICS; ASTROMETRY AB This paper summarizes the limits of ground-based interferometry for differential astrometry as well as ground-based interferometry for direct detection of exo-planets and exo-zodi dust levels. For direct detection, ground-based interferometry at near IR wavelengths using large telescopes with adaptive optics offers a significant advantage over single telescopes with adaptive optics. Ground-based differential astrometry for exo-planet detection is extremely accurate with sufficient accuracy to detect Neptune mass planets around 400 - 600 nearby stars. Ground-based interferometry using large (>6m) telescopes is also capable of detecting the 10 mu m emission of the zodiacal light around nearby stars with zodi levels similar to our solar system. RP Shao, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 241 IS 1 BP 105 EP 110 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WR628 UT WOS:A1996WR62800010 ER PT J AU Borucki, WJ Dunham, EW Koch, DG Cochran, WD Rose, JD Cullers, DK Granados, A Jenkins, JM AF Borucki, WJ Dunham, EW Koch, DG Cochran, WD Rose, JD Cullers, DK Granados, A Jenkins, JM TI FRESIP: A mission to determine the character and frequency of extra-solar planets around solar-like stars SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Conference on the Search for Extra-Solar Terrestrial Planets: Techniques and Technology CY MAY 14-17, 1995 CL BOULDER, CO ID MAIN-SEQUENCE STARS; RADIAL-VELOCITY; BINARY-SYSTEMS; STABILITY; ORBITS; TRANSITS; CRITERIA AB FRESIP (FRequency of Earth-Sized Inner Planets) is a mission designed to detect and characterize Earth-sizes planets around solar-like stars. The sizes of the planets are determined from the decrease in light from a star that occurs during planetary transits, while the orbital period is determined from the repeatability of the transits. Measurements of these parameters can be compared to theories that predict the spacing of planets, their distribution of size with orbital distance, and the variation of these quantities with stellar type and multiplicity. Because thousands of stars must be continually monitored to detect the transits, much information on the stars can be obtained on their rotation rates and activity cycles. Observations of p-mode oscillations also provide information on their age and composition. These goals are accomplished by continuously and simultaneously monitoring 5000 solar-like stars for evidence of brightness changes caused by Earth-sized or larger planetary transits. To obtain the high precision needed to find planets as small as the Earth and Venus around solar-like stars, a wide field of view Schmidt telescope with an array of CCD detectors at its focal plane must be located outside of the Earth's atmosphere. SMM (Solar Maximum Mission) observations of the low-level variability of the Sun (similar to 1:100,000) on the time scales of a transit (4 to 16 hours), and our laboratory measurements of the photometric precision of charge-coupled devices (1:100,000) show that the detection of planets as small as the Earth is practical. The probability for detecting transits is quite favorable for planets in inner orbits. If other planetary systems are similar to our own, then approximately 1% of those systems will show transits resulting in the discovery of 50 planetary systems in or near the habitable zone of solar-like stars. C1 UNIV TEXAS,AUSTIN,TX 78712. SETI INST,MT VIEW,CA 94043. RP Borucki, WJ (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 46 TC 15 Z9 16 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 241 IS 1 BP 111 EP 134 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WR628 UT WOS:A1996WR62800011 ER PT J AU Dolan, JF Boyd, PT Nelson, MJ Percival, JW Taylor, MJ vanCitters, GW AF Dolan, JF Boyd, PT Nelson, MJ Percival, JW Taylor, MJ vanCitters, GW TI Hubble space telescope observations of AGN's in the ultraviolet: BL Lac and Q2345+007* SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article ID GRAVITATIONAL LENS 0957+561; TIME-DELAY; LINEAR-POLARIZATION; LACERTAE; POLARIMETRY; PHOTOMETRY; OBJECTS; NOISE AB We report the first polarimetric observations in the ultraviolet of two AGN's, the blazar BL Lac and the gravitational lens candidate Q2345+007. We find strong (p > 3%) and variable UV polarization in BL Lac, two of the characteristics exhibited by blazars in the visible. The polarization of BL Lac in the UV decreased significantly (from 18% to < 5%) over a timescale of days. The flux density in the polarimetric bandpass showed changes which were not correlated with the polarimetric changes. The behavior of BL Lac in the UV is consistent with the two-component model of its polarized flux proposed by Brindle et al. (1985). The UV properties of the images in the Q2345+007 system are consistent with a gravitational lens interpretation. The QSO imaged in Q2345+007A is an excellent candidate to monitor for variable polarization on a timescale of weeks. Detecting the same polarimetric variation in each image of a gravitational lens may be the most effective method of determining the time-of-flight difference between the two image paths. C1 UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. UNIV WISCONSIN,SPACE ASTRON LAB,MADISON,WI 53706. NATL SCI FDN,DIV ASTRON SCI,ARLINGTON,VA 22230. RP Dolan, JF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Boyd, Patricia/D-3274-2012 NR 29 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 240 IS 2 BP 295 EP 303 DI 10.1007/BF00639593 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC594 UT WOS:A1996WC59400012 ER PT J AU Serlemitsos, PJ Soong, Y AF Serlemitsos, PJ Soong, Y TI Foil X-ray mirrors SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article AB Nested thin foil reflectors have made possible light weight, inexpensive and fast grazing incidence X-ray mirrors for astronomical spectroscopy over a broad band. These mirrors were developed at Goddard for the US Shuttle program and were flown on NASA's shuttle-borne Astro-l mission in December 1990. Presently, the Japan/US collaborative spectroscopic mission ASCA, nearing it's third year of successful operation in earth orbit, carries four such mirrors, weighing less than 40 kg and giving total effective areas of similar to 1200 and 420 cm(2) at 1 and 8 keV respectively. The similar to 420 kg observatory is the best possible example of how conical foil mirrors opened areas of research that could not have been otherwise addressed with available resources. In this paper, we will briefly review the development and performance of our first generation foil mirrors. We will also describe progress toward improving their imaging capability to prime them for use in future instruments. Such a goal is highly desirable, if not necessary for this mirror technology to remain competitive for future applications. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. RP Serlemitsos, PJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,XRAY ASTROPHYS BRANCH,CODE 662,GREENBELT,MD 20771, USA. NR 9 TC 47 Z9 47 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 239 IS 2 BP 177 EP 196 DI 10.1007/BF00645773 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WB597 UT WOS:A1996WB59700002 ER PT J AU Jenkins, EB Reale, MA Zucchino, PM Sofia, UJ AF Jenkins, EB Reale, MA Zucchino, PM Sofia, UJ TI High resolution spectroscopy in the far UV: Observations of the interstellar medium by IMAPS on ORFEUS-SPAS SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE detectors; spectrographs; data analysis; ultraviolet spectroscopy; high resolution spectroscopy; interstellar medium ID PI-SCORPII; NA I; ULTRAVIOLET; PERFORMANCE; INSTRUMENTATION; EXCITATION; LINES; GAS; IUE AB The Interstellar Medium Absorption Profile Spectrograph (IMAPS) is an objective-grating, echelle spectrograph built to observe the spectra of bright, hot stars over the spectral region 950-1150 Angstrom, below the wavelength coverage of HST. This instrument has a high wavelength resolving power, making it especially well suited for studies of interstellar absorption lines. Following a series of sounding rocket flights in the 1980's, IMAPS hew on its first Shuttle-launched orbital mission in September 1993, as a partner in the ORFEUS-SPAS program sponsored by the US and German Space Agencies, NASA and DARA. On ORFEUS-SPAS, IMAPS spent one day of orbital time observing the spectra of 10 O- and early B-type stars. In addition to outlining how IMAPS works, we document some special problems that had an influence on the data, and we explain the specific steps in data reduction that were employed to overcome them. This discussion serves as a basic source of information for people who may use archival data from this flight, as well as those who are interested in some specific properties of the data that will be presented in forthcoming research papers. IMAPS is scheduled to fly once again on ORFEUS-SPAS in late 1996. On this flight, 50% of the observing time available for IMAPS and two other spectrographs on the mission will be available to guest observers. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP Jenkins, EB (reprint author), PRINCETON UNIV OBSERV, PEYTON HALL, PRINCETON, NJ 08544 USA. RI Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 38 TC 21 Z9 21 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1996 VL 239 IS 2 BP 315 EP 360 DI 10.1007/BF00645785 PG 46 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WB597 UT WOS:A1996WB59700014 ER PT B AU Drake, SA Singh, KP White, NE AF Drake, SA Singh, KP White, NE BE Bowyer, S Malina, RF TI A re-analysis of the X-ray spectrum of HR 1099 and its implications for coronal abundances SO ASTROPHYSICS IN THE EXTREME ULTRAVIOLET LA English DT Proceedings Paper CT 152nd IAU Colloquium on Astrophysics in the Extreme Ultraviolet CY MAR 27-30, 1995 CL BERKELEY, CA SP IAU C1 NASA,GODDARD SPACE FLIGHT CTR,HEASARC,GREENBELT,MD 20771. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-3908-8 PY 1996 BP 147 EP 151 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BE98L UT WOS:A1996BE98L00023 ER PT B AU Hubeny, I Lanz, T AF Hubeny, I Lanz, T BE Bowyer, S Malina, RF TI EUV radiation from hot star photospheres: Theory versus observations SO ASTROPHYSICS IN THE EXTREME ULTRAVIOLET LA English DT Proceedings Paper CT 152nd IAU Colloquium on Astrophysics in the Extreme Ultraviolet CY MAR 27-30, 1995 CL BERKELEY, CA SP IAU C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. NR 0 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-3908-8 PY 1996 BP 381 EP 388 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BE98L UT WOS:A1996BE98L00061 ER PT J AU ShafferBailey, M Greenleaf, JE Hutchinson, TM AF ShafferBailey, M Greenleaf, JE Hutchinson, TM TI Isokinetic and isometric strength-endurance after 6 hours of immersion and 6 degrees head-down tilt in men SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID WATER IMMERSION; BED REST; SIMULATED WEIGHTLESSNESS; HEALTHY-MEN; HUMANS; MICROGRAVITY; VOLUME; VELOCITY; BEDREST; MUSCLES AB Purpose: To determine weight (water) loss levels for onset of muscular strength and endurance changes during deconditioning. Methods: Seven men (27-40 yr) performed maximal shoulder-, knee-, and ankle-joint isometric (0 degrees . s(-1) load) and isokinetic (60 degrees, 120 degrees, 180 degrees . s(-1) velocity) exercise tests during ambulatory control (AC), after 6 h of 6 degrees head-down tilt (HDT; dry-bulb temp. = 23.2 +/- SD 0.6 degrees C, relative humidity = 31.1 +/- 11.1%) and after 6 h of 80 degrees foot-down head-out water immersion (WI; water temp. = 35.0 +/- SD 0.1 degrees C) treatments. Results: Weight (water) loss after HDT (1.10 +/- SE 0.14 kg, 1.4 +/- 0.2% body wt) and WI (1.54 +/- 0.19 kg, 2.0 +/- 0.2% body wt) were not different, but urinary excretion with WI (1,354 +/- 142 ml . 6 h(-1)) was 28% greater (p < 0.05) than that of 975 +/- 139 ml . 6 h(-1) with HDT. Muscular endurance (total work; maximal flexion-extension of the non-dominant knee at 180 degrees . s(-1) for 30 s) was not different between AC and the WI or HDT treatments. Shoulder-, knee-, and ankle-joint strength was unchanged except for three knee-joint peak torques: AC torque (120 degrees . s(-1), 285 +/- 20 Nm) decreased to 268 +/- 21 Nm (Delta = -6%, p < 0.05) with WI; and AC torques (180 degrees . s(-1), 260 +/- 19 Nm) decreased to 236 +/- 15 Nm (Delta = -9%, p < 0.01) with HDT, and to 235 +/- 19 Nm (Delta = -10%, p < 0.01) with WI. Conclusion: Thus, the total body hypohydration threshold level for shoulder- and ankle-joint strength and endurance decrements is more than 2% body weight (water) loss, while significant reduction in knee-joint muscular strength-endurance occurred only at moderate (120 degrees . s(-1)) and lighter (180 degrees . s(-1)) loads with body weight loss of 1.4-2.0% following WI or HDT, respectively. These weight (water) losses and knee-joint strength decrements are somewhat less than the mean weight loss of 2.6% and knee-joint strength decrements of 6-20% of American astronauts after Skylab flights to 84 d. C1 NASA,AMES RES CTR,GRAVIAT RES BRANCH 23911,LAB HUMAN ENVIRONM PHYSIOL,MOFFETT FIELD,CA 94035. NR 27 TC 1 Z9 1 U1 0 U2 2 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 JAN PY 1996 VL 67 IS 1 BP 46 EP 51 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA TP715 UT WOS:A1996TP71500010 PM 8929202 ER PT J AU Gawronski, W AF Gawronski, W TI Balanced control of flexible structures - Introduction SO BALANCE CONTROL OF FLEXIBLE STRUCTURES SE LECTURE NOTES IN CONTROL AND INFORMATION SCIENCES LA English DT Editorial Material RP Gawronski, W (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 8 TC 0 Z9 0 U1 1 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN 33 PA HEIDELBERGER PLATZ 3, W-1000 BERLIN 33, GERMANY SN 0170-8643 J9 LECT NOTES CONTR INF PY 1996 VL 211 BP 4 EP & PG 4 WC Automation & Control Systems; Computer Science, Information Systems SC Automation & Control Systems; Computer Science GA BF73L UT WOS:A1996BF73L00001 ER PT B AU Stewart, KT Eastman, CI AF Stewart, KT Eastman, CI BE Holick, MF Jung, EG TI The light stuff: Shiftwork, circadian rhythms, and manned spaceflight SO BIOLOGIC EFFECTS OF LIGHT 1995 LA English DT Proceedings Paper CT 4th International Arnold Rikli Symposium on Biologic Effects of Light CY OCT 09-11, 1995 CL ATLANTA, GA SP Inst Friedrich Wolff AG, Light Symp Fdn RP Stewart, KT (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058, USA. NR 0 TC 10 Z9 11 U1 0 U2 0 PU WALTER DE GRUYTER PI BERLIN 30 PA GENTHINER STRASSE 13, W-1000 BERLIN 30, GERMANY BN 3-11-014899-4 PY 1996 BP 340 EP 347 PG 8 WC Biophysics; Dermatology SC Biophysics; Dermatology GA BH54R UT WOS:A1996BH54R00054 ER PT B AU Ansari, RR Suh, KI AF Ansari, RR Suh, KI BE AnderssonEagels, S Corti, M Kroo, N Kertesz, I King, TA Pratesi, R Seeger, S Weber, HP Katzir, A TI Sizing of colloidal particles and protein molecules in a hanging fluid drop SO BIOMEDICAL OPTOELECTRONICS IN CLINICAL CHEMISTRY AND BIOTECHNOLOGY, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1995 Biomedical Optics Symposium (BIOS Europe 95) CY SEP 14-15, 1995 CL BARCELONA, SPAIN SP European Laser Assoc, Soc Espanola Laser Med Quirurgico, Essilor Int, Int Biomed Opt Soc, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Commun, Directorate Gen Sci Res & Dev C1 NASA,LEWIS RES CTR,MICROGRAV FLUIDS BRANCH,SPACE EXPT DIV,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-1993-1 J9 P SOC PHOTO-OPT INS PY 1996 VL 2629 BP 157 EP 167 DI 10.1117/12.229510 PG 11 WC Chemistry, Medicinal; Engineering, Biomedical; Optics SC Pharmacology & Pharmacy; Engineering; Optics GA BF18S UT WOS:A1996BF18S00018 ER PT J AU Towe, BC Flechsig, S Spaulding, G AF Towe, BC Flechsig, S Spaulding, G TI A recirculating-flow fluorescent oxygen sensor SO BIOSENSORS & BIOELECTRONICS LA English DT Article; Proceedings Paper CT 4th World Congress on Biosensors CY 1996 CL BANGKOK, THAILAND DE oxygen sensor; fluorescent biosensor ID GLUCOSE BIOSENSOR; MICRODIALYSIS AB An immersible oxygen sensor was constructed by circulating small quantities of ruthenium tris-(2,2'-bipyridyl) II dichloride oxygen-sensitive fluorescent dye through a loop of oxygen-permeable silicone tubing immersed in test medium. The fluroescence intensity of the dye was subsequently measured as it exited the flow loop and related to oxygen tension. This method of measuring the oxygen tension, through diffusive transport to a flowing stream of dye and recirculating it in the sensor, has been found to give a stable response and relatively long sensor lifetime without major recalibration. The sensor showed good stability over at least a week's duration and showed no degradation due to leaching of the dye through membranes or photobleaching that commonly affects fluorescent sensors with immobilized chemistries. (C) 1996 Elsevier Science Limited C1 NASA,JOHNSON SPACE CTR,HOUSTON,TX 77059. RP Towe, BC (reprint author), ARIZONA STATE UNIV,BIOENGN PROGRAM,TEMPE,AZ 85287, USA. NR 11 TC 5 Z9 6 U1 0 U2 2 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0956-5663 J9 BIOSENS BIOELECTRON JI Biosens. Bioelectron. PY 1996 VL 11 IS 8 BP 799 EP 803 DI 10.1016/0956-5663(96)85931-8 PG 5 WC Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology SC Biophysics; Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics GA UN103 UT WOS:A1996UN10300013 ER PT J AU Noever, DA Brittain, A Matsos, HC Baskaran, S Obenhuber, D AF Noever, DA Brittain, A Matsos, HC Baskaran, S Obenhuber, D TI The effects of variable biome distribution on global climate SO BIOSYSTEMS LA English DT Article DE variable biome; genetic algorithm; albedo and radiation effects; greenhouse effect; temperature balance ID TERRESTRIAL CARBON STORAGE; LAST GLACIAL MAXIMUM; VEGETATION; SENSITIVITY; MODEL AB In projecting climatic adjustments to anthropogenically elevated atmospheric carbon dioxide, most global climate models fur biome distribution to current geographic conditions. Previous biome maps either remain unchanging or shift without taking into account climatic feedbacks such as radiation and temperature. We develop a model that examines the albedo-related effects of biome distribution on global temperature. The model was tested on historical biome changes since 1860 and the results fit both the observed temperature trend and order of magnitude change. The model is then used to generate an optimized future biome distribution that minimizes projected greenhouse effects on global temperature. Because of the complexity of this combinatorial search, an artificial intelligence method, the genetic algorithm, was employed. The method is to adjust biome areas subject to a constant global temperature and total surface area constraint. For regulating global temperature, oceans are found to dominate continental biomes. Algal beds are significant radiative levers as are other carbon intensive biomes including estuaries and tropical deciduous forests. To hold global temperature constant over the next 70 years this simulation requires that deserts decrease and forested areas increase. The effect of biome change on global temperature is revealed as a significant forecasting factor. RP Noever, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 25 TC 2 Z9 2 U1 2 U2 15 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0303-2647 J9 BIOSYSTEMS JI Biosystems PY 1996 VL 39 IS 2 BP 135 EP 141 DI 10.1016/0303-2647(96)01611-5 PG 7 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA VD938 UT WOS:A1996VD93800006 PM 8866050 ER PT J AU Ying, R Canuto, VM AF Ying, R Canuto, VM TI Turbulence modelling over two-dimensional hills using an algebraic Reynolds stress expression SO BOUNDARY-LAYER METEOROLOGY LA English DT Article ID BOUNDARY-LAYER FLOW; REAL TERRAIN; CLOSURE AB We carry out model studies of turbulence quantities for flow over two-dimensional hills using anon-hydrostatic version of the Regional Atmospheric Modeling System (RAMS). We test two turbulence closure models: the first one is an explicit Algebraic Reynolds Stress Model (ARSM) and the second one is a combination of the ARSM and a transport equation for the shear stress <(uw)over bar>. Model predictions for the turbulent stresses are compared with data from a wind-tunnel experiment containing isolated two-dimensional hills of varying slope. From the comparison, it is concluded that the first model can only predict the normal stresses adequately while the second model provides satisfactory predictions for the normal stresses as well as giving an improved result for the shear stress <(uw)over bar>. RP Ying, R (reprint author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 32 TC 20 Z9 22 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD JAN PY 1996 VL 77 IS 1 BP 69 EP 99 DI 10.1007/BF00121859 PG 31 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA UA758 UT WOS:A1996UA75800004 ER PT J AU Stoner, AW Pitts, PA Armstrong, RA AF Stoner, AW Pitts, PA Armstrong, RA TI Interaction of physical and biological factors in the large-scale distribution of juvenile queen conch in seagrass meadows SO BULLETIN OF MARINE SCIENCE LA English DT Article ID STROMBUS-GIGAS; POPULATION-STRUCTURE; MARICULTURE; MIGRATION; HABITATS; ISLANDS; BAHAMAS; GROWTH AB Large-scale distribution of a large, commercially significant gastropod, Strombus gigas (queen conch), was investigated in a 11,000-ha region of the Great Bahama Bank near Lee Stocking Island, Exuma Gays. Maps of depth and seagrass biomass, generated with Landsat thematic mapper data, and a 4-year survey of juvenile conch distribution showed that most of the juveniles were in aggregations located in 1.5-4.0-m water depth. Although general locations of juvenile conch aggregations remained the same between 1989 and 1992, their total surface area occupied only about 1.5% of the 8,300 ha of seagrass habitat available. Locations of only the most persistent long-term aggregations could be predicted on the basis of preferred seagrass biomass (30-80 g dry weight m(-2)); however, important conch nurseries were always located in tidal channels which brought clear, oligotrophic water from the Exuma Sound. Harmonic analysis of water temperature data from sites with and without juvenile aggregations showed that conch nurseries were subject to flushing with oceanic water on every tide, whereas non-conch sites reflected only diurnal heating and cooling of bank water. Relationships between circulation and juvenile conch distribution on the Great Bahama Bank may be related directly to larval recruitment, or indirectly to aspects of nutrient cycling and food production; evidence for both mechanisms exists. Although exact locations of conch aggregations shift from year to year, these shifts appear to occur within larger nursery habitats, the boundaries of which are set by a precise combination of physical and biological factors. Because most meadows are probably unsuitable for this severely overfished species, critical nursery habitats should be identified and protected. C1 HARBOR BRANCH OCEANOG INST INC, FT PIERCE, FL 34946 USA. NASA, AMES RES CTR, JOHNSON CONTROLS WORLD SERV INC, MOFFETT FIELD, CA 94305 USA. RP Stoner, AW (reprint author), CARIBBEAN MARINE RES CTR, 805 E 46TH PL, VERO BEACH, FL 32963 USA. NR 34 TC 38 Z9 38 U1 0 U2 8 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JAN PY 1996 VL 58 IS 1 BP 217 EP 233 PG 17 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA TP479 UT WOS:A1996TP47900013 ER PT J AU Ware, R Exner, M Feng, D Gorbunov, M Hardy, K Herman, B Kuo, Y Meehan, T Melbourne, W Rocken, C Schreiner, W Sokolovskiy, S Solheim, F Zou, X Anthes, R Businger, S Trenberth, K AF Ware, R Exner, M Feng, D Gorbunov, M Hardy, K Herman, B Kuo, Y Meehan, T Melbourne, W Rocken, C Schreiner, W Sokolovskiy, S Solheim, F Zou, X Anthes, R Businger, S Trenberth, K TI GPS sounding of the atmosphere from low earth orbit: Preliminary results SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID RADIO OCCULTATION MEASUREMENTS; GLOBAL POSITIONING SYSTEM; WATER-VAPOR; TEMPERATURE; CLIMATE; VOYAGER; NEPTUNE; VENUS AB This paper provides an overview of the methodology of and describes preliminary results from an experiment called GPS/MET (Global Positioning System/Meteorology), in which temperature soundings are obtained from a low Earth-orbiting satellite using the radio occultation technique. Launched into a circular orbit of about 750-km altitude and 70 degrees inclination on 3 April 1995, a small research satellite, MicroLab 1, carried a laptop-sized radio receiver. Each time this receiver rises and sets relative to the 24 operational GPS satellites, the GPS radio waves transect successive layers of the atmosphere and are bent (refracted) by the atmosphere before they reach the receiver, causing a delay in the dual-frequency carrier phase observations sensed by the receiver. During this occultation, GPS limb sounding measurements are obtained from which vertical profiles of atmospheric refractivity can be computed. The refractivity is a function of pressure, temperature, and water vapor and thus provides information on these variables that has the potential to be useful in weather prediction and weather and climate research. Because of the dependence of refractivity on both temperature and water vapor, it is generally impossible to compute both variables from a refractivity sounding. However, if either temperature or water vapor is known from independent measurements or from model predictions, the other variable may be calculated. In portions of the atmosphere where moisture effects are negligible (typically above 5-7 km), temperature may be estimated directly from refractivity. This paper compares a representative sample of 11 temperature profiles derived from GPS/MET soundings (assuming a dry atmosphere) with nearby radiosonde and high-resolution balloon soundings and the operational gridded analysis of the National Centers for Environmental Prediction (formerly the National Meteorological Center). One GPS/MET profile was obtained at a location where a temperature profile from the Halogen Occultation Experiment was available for comparison. These comparisons show that accurate vertical temperature profiles may be obtained using the GPS limb sounding technique from approximately 40 km to about 5-7 km in altitude where moisture effects are negligible. Temperatures in this region usually agree within 2 degrees C with the independent sources of data. The GPS/MET temperature profiles show vertical resolution of about 1 km and resolve the location and minimum temperature of the tropopause very well. Theoretical temperature accuracy is better than 0.5 degrees C at the tropopause, degrading to about 1 degrees C at 40-km altitude. Above 40 km and below 5 km, these preliminary temperature retrievals show difficulties. In the upper atmosphere, the errors result from initial temperature and pressure assumptions in this region and initial ionospheric refraction assumptions. In the lower troposphere, the errors appear to be associated with multipath effects caused by large gradients in refractivity primarily due to water vapor distribution. C1 UNIV CORP ATMOSPHER RES,BOULDER,CO 80303. UNIV NAVSTAR CONSORTIUM,BOULDER,CO. UNIV ARIZONA,TUCSON,AZ. RUSSIAN INST ATMOSPHER PHYS,MOSCOW,RUSSIA. LOCKHEED MARTIN MISSILES & SPACE,PALO ALTO,CA. NATL CTR ATMOSPHER RES,BOULDER,CO 80307. CALTECH,JET PROP LAB,PASADENA,CA. UNIV HAWAII MANOA,HONOLULU,HI 96822. RI Trenberth, Kevin/A-5683-2012 OI Trenberth, Kevin/0000-0002-1445-1000 NR 65 TC 375 Z9 412 U1 3 U2 17 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 JAN PY 1996 VL 77 IS 1 BP 19 EP 40 DI 10.1175/1520-0477(1996)077<0019:GSOTAF>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA TT952 UT WOS:A1996TT95200002 ER PT J AU Turyshev, SG AF Turyshev, SG TI Black holes with regular horizons in Maxwell-scalar gravity SO CANADIAN JOURNAL OF PHYSICS LA English DT Article ID DILATON FIELD; EQUATIONS AB A class of exact static spherically symmetric solutions of the Einstein-Maxwell gravity coupled to a massless scalar field is obtained in the harmonic coordinates of Minkowski space-time. For each value of the coupling constant a, these solutions are characterized by a set of three parameters, the physical mass mu(0), the electric charge Q(0) and the sealar-field parameter k. We find that the solutions for both gravitational and electromagnetic fields are not only affected by the scalar field, but also the nontrivial coupling with matter constrains the scalar field itself. In particular, we find that the constant k differs generically from +/-1/2, falling into the interval \k\ is an element of [0, 1/2 root 1 + a(2)]. It takes these values only for black holes or in the case when a scalar field phi is totally decoupled from the matter. Our results differ from those previously obtained in that the presence of an arbitrary coupling constant a gives an opportunity to rule out the nonphysical horizons. In one of the special cases, the obtained solution corresponds to a charged dilatonic black hole with only one horizon mu(+) and hence to the Kaluza-Klein case. The most remarkable property of this result is that the metric, the scalar curvature, and both the electromagnetic and scalar fields are all regular on this surface. Moreover, while studying the dilaton charge, we found that the inclusion of the scalar field in the theory resulted in a contraction of the horizon. The behavior of the scalar curvature was analysed. RP Turyshev, SG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 22 TC 2 Z9 2 U1 0 U2 1 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD JAN-FEB PY 1996 VL 74 IS 1-2 BP 17 EP 28 DI 10.1139/p96-004 PG 12 WC Physics, Multidisciplinary SC Physics GA TZ391 UT WOS:A1996TZ39100004 ER PT B AU Spehalski, RJ AF Spehalski, RJ BE Horn, L TI The Cassini mission to Saturn SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; Huygens; Saturn; Titan; spacecraft; orbiter; probe; National Aeronautics and Space Administration (NASA); European Space Agency (ESA); Agenzia Spaziale Italiana (ASI/Italian Space Agency) C1 JET PROP LAB,PASADENA,CA 91109. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 2 EP 9 DI 10.1117/12.253409 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00001 ER PT B AU Kindt, DH AF Kindt, DH BE Horn, L TI Cassini/Huygens, a challenge in international interface design, integration and cooperation SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; Huygens; Saturn; Titan; Probe; JPL; ESA; NASA C1 JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 10 EP 21 DI 10.1117/12.253419 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00002 ER PT B AU Matson, DL AF Matson, DL BE Horn, L TI The Cassini/Huygens mission to the Saturnian system SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; Huygens; Saturn; Titan; spacecraft; probe; satellite; rings; moons; magnetosphere; atmosphere C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 22 EP 29 DI 10.1117/12.253423 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00003 ER PT B AU Wolf, AA AF Wolf, AA BE Horn, L TI Touring the saturnian system SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE flyby; gravitational assist; trajectory; satellite tour C1 CALTECH,JET PROP LAB,PASADENA,CA 91009. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 32 EP 44 DI 10.1117/12.253431 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00004 ER PT B AU Jaffe, LD Herrell, LM AF Jaffe, LD Herrell, LM BE Horn, L TI Cassini/Huygens science instruments SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; Huygens; instruments; Saturn; Titan C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 84 EP 106 DI 10.1117/12.253410 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00009 ER PT B AU Bradley, JG Grun, E Srama, R AF Bradley, JG Grun, E Srama, R BE Horn, L TI The cosmic dust analyzer for Cassini SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE cosmic dust; dust impact analyzer; Cassini Mission; Saturn C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 108 EP 117 DI 10.1117/12.253411 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00010 ER PT B AU Kasprzak, W Niemann, H Harpold, D Richards, J Manning, H Patrick, E Mahaffy, P AF Kasprzak, W Niemann, H Harpold, D Richards, J Manning, H Patrick, E Mahaffy, P BE Horn, L TI Cassini orbiter ion and neutral mass spectrometer instrument SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; Titan; INMS; Mass Spectrometer; Ion and Neutral Mass Spectrometer C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Harpold, Dan/I-3345-2013 NR 0 TC 21 Z9 21 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 129 EP 140 DI 10.1117/12.253413 PG 4 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00012 ER PT B AU Kunde, V Ade, P Barney, R Bergman, D Bonnal, JF Borelli, R Boyd, D Brasunas, J Brown, G Calcutt, S Carroll, F Courtin, R Cretolle, J Crooke, J Davis, M Edberg, S Fettig, R Flasar, M Glenar, D Graham, S Hagopian, J Hakun, C Hayes, P Herath, L Horn, L Jennings, D Karpati, G Kellebenz, C Lakew, B Lindsay, J Lohr, J Lyons, J Martineau, R Martino, A Matsumura, M McCloskey, J Melak, T Michel, G Morell, A Mosier, C Pack, L Plants, M Robinson, D Rodriguez, L Romani, P Schaefer, W Schmidt, S Trujillo, C Vellacott, T Wagner, K Yun, D AF Kunde, V Ade, P Barney, R Bergman, D Bonnal, JF Borelli, R Boyd, D Brasunas, J Brown, G Calcutt, S Carroll, F Courtin, R Cretolle, J Crooke, J Davis, M Edberg, S Fettig, R Flasar, M Glenar, D Graham, S Hagopian, J Hakun, C Hayes, P Herath, L Horn, L Jennings, D Karpati, G Kellebenz, C Lakew, B Lindsay, J Lohr, J Lyons, J Martineau, R Martino, A Matsumura, M McCloskey, J Melak, T Michel, G Morell, A Mosier, C Pack, L Plants, M Robinson, D Rodriguez, L Romani, P Schaefer, W Schmidt, S Trujillo, C Vellacott, T Wagner, K Yun, D BE Horn, L TI Cassini infrared Fourier spectroscopic investigation SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; infrared spectroscopy; Fourier spectrometer; planetary atmospheres; space instrumentation; remote sensing C1 GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Flasar, F Michael/C-8509-2012; Romani, Paul/D-2729-2012; brasunas, john/I-2798-2013; OI Calcutt, Simon/0000-0002-0102-3170 NR 0 TC 69 Z9 69 U1 0 U2 4 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 162 EP 177 DI 10.1117/12.253416 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00015 ER PT B AU Martineau, RJ Hu, K Manthripragada, S Kotecki, CA Babu, S Peters, FA Burgess, AS Mott, DB Krebs, DJ Graham, S Ewin, AJ Miles, A Bly, V Nguyen, TL McCloskey, J Shu, PK AF Martineau, RJ Hu, K Manthripragada, S Kotecki, CA Babu, S Peters, FA Burgess, AS Mott, DB Krebs, DJ Graham, S Ewin, AJ Miles, A Bly, V Nguyen, TL McCloskey, J Shu, PK BE Horn, L TI HgCdTe detector technology and performance for the Composite Infrared Spectrometer (CIRS)/Cassini Mission SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE HgCdTe; infrared detector; focal plane array; split-geometry detectors C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 178 EP 186 DI 10.1117/12.253417 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00016 ER PT B AU Kahn, CL King, WS AF Kahn, CL King, WS BE Horn, L TI Cassini Imaging Science Subsystem SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE imaging; CCD; camera; Saturn C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 187 EP 196 DI 10.1117/12.253418 PG 4 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00017 ER PT B AU Avis, C Yoshimizu, J AF Avis, C Yoshimizu, J BE Horn, L TI ISS calibration analysis support system SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE instrument calibration; image processing; Cassini C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 197 EP 205 DI 10.1117/12.253420 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00018 ER PT B AU Miller, E Klein, G Juergens, D Mehaffey, K Oseas, J Garcia, R Giandomenico, A Irigoyen, B Hickok, R Rosing, D Sobel, H Bruce, C Flamini, E DeVidi, R Reininger, F Dami, M Soufflot, A Langevin, Y Huntzinger, G AF Miller, E Klein, G Juergens, D Mehaffey, K Oseas, J Garcia, R Giandomenico, A Irigoyen, B Hickok, R Rosing, D Sobel, H Bruce, C Flamini, E DeVidi, R Reininger, F Dami, M Soufflot, A Langevin, Y Huntzinger, G BE Horn, L TI The Visual and Infrared Mapping Spectrometer for Cassini SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE imaging spectrometers; Cassini; planetary; multispectral; infrared; visible; CCD; InSb C1 JET PROPULS LAB,PASADENA,CA. NR 0 TC 22 Z9 22 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 206 EP 220 DI 10.1117/12.253421 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00019 ER PT B AU Sarrel, M AF Sarrel, M BE Horn, L TI Cassini Science Operations and Planning Computer design SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; ground system; space exploration; planetary science; distributed operations; SOPC C1 NASA,CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 222 EP 233 DI 10.1117/12.253422 PG 2 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00020 ER PT B AU Wessen, RR Porter, D AF Wessen, RR Porter, D BE Horn, L TI Evaluation of the Cassini Resource Exchange SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE spacecraft; Cassini; instrument; development C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 234 EP 244 DI 10.1117/12.253424 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00021 ER PT B AU Gibbs, R AF Gibbs, R BE Horn, L TI Cassini spacecraft design SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; spacecraft; Huygens; Saturn; Titan C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 246 EP 258 DI 10.1117/12.253425 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00022 ER PT B AU Strauss, KF Stockton, GJ AF Strauss, KF Stockton, GJ BE Horn, L TI The Cassini solid-state recorder: A high-capacity, radiation-tolerant high-performance unit SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE application-specific integrated circuits; data acquisition; fault tolerance; tape recording; partition (memory); recording instruments; solid state; dynamic random-access memory C1 CALTECH,JET PROPULS LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 259 EP 270 DI 10.1117/12.253426 PG 4 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00023 ER PT B AU Rasmussen, RD Singh, G Rathbun, DB Macala, GA AF Rasmussen, RD Singh, G Rathbun, DB Macala, GA BE Horn, L TI Behavioral model pointing on Cassini using target vectors SO CASSINI/HUYGENS: A MISSION TO THE SATURNIAN SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Cassini/Huygens - A Mission to the Saturnian Systems CY AUG 05-06, 1996 CL DENVER, CO SP Soc Photo Opt Instrumentat Engineers, N Amer Remote Sensing Ind Assoc, Amer Soc Photogrammetry & Remote Sensing DE Cassini; pointing; attitude control; target motion; constraint C1 CALTECH,JET PROP LAB,PASADENA,CA. NR 0 TC 0 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2191-X J9 P SOC PHOTO-OPT INS PY 1996 VL 2803 BP 271 EP 287 DI 10.1117/12.253427 PG 3 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BG52F UT WOS:A1996BG52F00024 ER EF