FN Thomson Reuters Web of Science™ VR 1.0 PT J AU MASSA, D ALTNER, B WYNNE, D LAMERS, HJGLM AF MASSA, D ALTNER, B WYNNE, D LAMERS, HJGLM TI CARBON AND NITROGEN ABUNDANCES IN THE BN SUPERGIANT HD-93840, AND THEIR IMPLICATIONS FOR NORMAL GALACTIC SUPERGIANTS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE STARS EARLY-TYPE; ATMOSPHERES; ABUNDANCES ID ULTRAVIOLET SPECTRAL MORPHOLOGY; MASSIVE CLOSE BINARIES; O-STARS; STELLAR WINDS; LINE-PROFILES; SEI METHOD; OBC STARS; SEQUENCE; CLASSIFICATION; COPERNICUS AB We use the photospheric UV silicon lines to demonstrate that HD 93840 has nearly the same temperature and surface gravity as the normal Bl Ib star zeta-Per. We then perform a differential abundance analysis between the two stars by analyzing their carbon and nitrogen wind line profiles. This analysis gives quantitative results which are independent of the usual model atmosphere analysis and, therefore, represent a valuable check on the validity of the model atmosphere approach. We find ratios for the carbon and nitrogen surface abundances in HD 93840 compared to zeta-Per of 1:10 and 4.6:1, respectively. We introduce a simple model for the compositions of both atmospheres. This model enables us to derive the fraction of material in each atmosphere which has undergone CNO processing - more than 90% for HD 93840 and less than about 15% for zeta Per (these results are only weakly dependent upon the specifics of the CNO processing). We argue that the enriched material must have resided in a nuclear burning core for only a very short time, since there is little evidence for the influences of the ON cycle. Our best estimates for the carbon abundances (by number) relative to cosmic are 0.09 +/- 0.07 and 0.90 +/- 0.1, for HD 93840 and zeta Per, respectively. The nitrogen abundances are somewhat more sensitive to how strongly the ON cycle has influenced the processed material. They can range from 6.10 +/- 0.44 to 11.2 +/- 0.70 for HD 93840 and 1.3 +/- 0.6 to 2.4 +/- 1.1 for zeta-Per. Finally, we discuss the possibility that the wind in HD 93840 is "line locked" at the N v doublet separation. C1 GODDARD SPACE FLIGHT CTR, COMP SCI CORP, GREENBELT, MD 20771 USA. SRON LAB SPACE RES, 3584 CA UTRECHT, NETHERLANDS. DEPT ASTRON, 3584 CA UTRECHT, NETHERLANDS. RP MASSA, D (reprint author), APPL RES CORP, 8201 CORP DR, LANDOVER, MD 20785 USA. NR 54 TC 7 Z9 7 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 1991 VL 242 IS 1 BP 188 EP 198 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EY069 UT WOS:A1991EY06900022 ER PT J AU GREVESSE, N LAMBERT, DL SAUVAL, AJ VANDISHOECK, EF FARMER, CB NORTON, RH AF GREVESSE, N LAMBERT, DL SAUVAL, AJ VANDISHOECK, EF FARMER, CB NORTON, RH TI VIBRATION-ROTATION BANDS OF CH IN THE SOLAR INFRARED-SPECTRUM AND THE SOLAR CARBON ABUNDANCE SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ABUNDANCES, SOLAR; ATOMIC AND MOLECULAR DATA; SOLAR SPECTRUM ID LASER-INDUCED FLUORESCENCE; OSCILLATOR STRENGTH MEASUREMENTS; VACUUM ULTRAVIOLET; NEUTRAL CARBON; LIFETIME MEASUREMENTS; OPACITY CALCULATIONS; DIATOMIC-MOLECULES; RADIATIVE LIFETIME; PHILLIPS SYSTEM; EXCITED-STATES AB High resolution solar spectra obtained from the ATMOS Fourier Transform Spectrometer (Spacelab 3 flight on April 29-May 6, 1985) have permitted us to identify and measure a large number of lines of the vibration-rotation fundamental bands of the X2 II state of CH. From about 100 lines of the 1-0, 2-1, and 3-2 bands and adopting theoretical transition probabilities, we derive a solar carbon abundance A(C) = 8.60 +/- 0.05. This value is compared with new results inferred from other carbon abundance indicators, such as the C2 Swan and Phillips bands, the CH A2 DELTA-X2 II transition, and the C I lines. Our final recommended solar abundance of carbon is A(C) = 8.60 +/- 0.05. C1 OBSERV ROYAL BELGIQUE, B-1180 BRUSSELS, BELGIUM. CALTECH, DIV GEOL & PLANETARY SCI, PASADENA, CA 91125 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV TEXAS, DEPT ASTRON, AUSTIN, TX 78712 USA. RP GREVESSE, N (reprint author), UNIV LIEGE, INST ASTROPHYS, B-4000 COINTE OUGREE, BELGIUM. NR 62 TC 161 Z9 161 U1 1 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 1991 VL 242 IS 2 BP 488 EP 495 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EZ007 UT WOS:A1991EZ00700024 ER PT J AU GOODE, PR DZIEMBOWSKI, WA KORZENNIK, SG RHODES, EJ AF GOODE, PR DZIEMBOWSKI, WA KORZENNIK, SG RHODES, EJ TI WHAT WE KNOW ABOUT THE SUNS INTERNAL-ROTATION FROM SOLAR OSCILLATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, OSCILLATIONS; SUN, ROTATION ID MODE FREQUENCY SPLITTINGS; LATITUDE; DEPTH AB The six available 5 minute period oscillation data sets have been inverted using the same method to determine the robust properties of the internal rotation rate of the Sun. The comprehensive result is that the rotation rate in the equatorial plane declines going inward between the surface and 0.6 of the radius and, with less certainty in the same region, the polar rate increases going inward. In other words, the surface-like differential rotation decreases with depth. The bulk of these changes occurs near the base of the convection zone. Going inward in the equatiorial plane from 0.6 to 0.4 of the radius, the rotation appears to be flat. Beneath 0.4 of the radius, we can make no appealing case for a rapidly rotating core. There is evidence that the internal rotation has changed systematically through this solar activity cycle. We also make a suggestion as to how oscillation data should be presented. C1 POLISH ACAD SCI,N COPERNICUS ASTRON CTR,WARSAW 42,POLAND. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. UNIV SO CALIF,DEPT ASTRON,LOS ANGELES,CA 90089. CALTECH,SPACE PHYS & ASTROPHYS SECT,JET PROPULS LAB,PASADENA,CA 91125. RP GOODE, PR (reprint author), NEW JERSEY INST TECHNOL,DEPT PHYS,NEWARK,NJ 07102, USA. NR 21 TC 91 Z9 92 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 1991 VL 367 IS 2 BP 649 EP 657 DI 10.1086/169660 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET683 UT WOS:A1991ET68300025 ER PT J AU CANFIELD, RC ZARRO, DM WULSER, JP DENNIS, BR AF CANFIELD, RC ZARRO, DM WULSER, JP DENNIS, BR TI A STUDY OF SOLAR-FLARE ENERGY-TRANSPORT BASED ON COORDINATED H-ALPHA AND X-RAY OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE LINE PROFILES; SUN, CHROMOSPHERE; SUN, CORONA; SUN, FLARES; SUN, X-RAYS ID LOOP RADIATIVE HYDRODYNAMICS; EXTREME-ULTRAVIOLET; NONTHERMAL ELECTRONS; MAXIMUM MISSION; BURSTS; SATELLITE; EMISSION; DYNAMICS; SPECTRA; RATIO AB Coordinated H-alpha, hard X-ray (HXR), and soft X-ray observations of five solar flares allow us to determine, for the first time, the temporal variation of the ratio of H-alpha to nonthermal hard X-ray emissions, and to compare its behavior to the predictions of a hydrostatic one-dimensional thick-target nonthermal electron model of solar flare energy transport. We have used the observations to estimate the emitted flare energy flux F(H)-alpha in H-alpha, the flux of energy F-20 deposited by nonthermal electrons with energies above 20 keV, and the pressure p(c) of soft X-ray emitting plasma as functions of time during the impulsive phase of each flare. The F(H)-alpha/F-20 ratio show a power-law dependence on F-20 of the form F(H)-alpha/F-20 proportional F-20-(0.7 +/- 0.1). Analyzing the observations with the thick-target model, we demonstrate that: (1) the power-law dependence of the F(H)-alpha/F-20 ratio on F-20 is consistent with that predicted by the model if the nonthermal electron precipitation area does not vary by more than a factor of five during the impulsive phase of the observed flares; (2) there is evidence for modification of the power-law dependence by hydrostatic pressure effects; (3) the observed magnitude of the F(H)-alpha/F-20 ratio implies a small precipitation area of approximately 10(17) cm2 and correspondingly large beam fluxes (approximately 10(12) ergs cm-2 s-1 for all five flares. C1 NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. APPL RES CORP,LANDOVER,MD 20785. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. RP CANFIELD, RC (reprint author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA. RI Dennis, Brian/C-9511-2012 NR 25 TC 11 Z9 11 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1991 VL 367 IS 2 BP 671 EP 676 DI 10.1086/169663 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET683 UT WOS:A1991ET68300028 ER PT J AU HACKING, PB SOIFER, BT AF HACKING, PB SOIFER, BT TI THE NUMBER COUNTS AND INFRARED BACKGROUNDS FROM INFRARED-BRIGHT GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY; GALAXIES-EVOLUTION; INFRARED-SOURCES ID DEEP IRAS SURVEY; EVOLUTION; SAMPLE AB We have predicted extragalactic number counts and diffuse backgrounds at 25, 60, and 100-mu-m using new luminosity functions and improved spectral energy distribution density functions derived from IRAS observations of nearby galaxies. Galaxies at redshifts z < 3 that are like those in the local universe should produce a minimum diffuse background of 8.5 x 10(-3), 3.8 x 10(-2), and 0.13 MJy sr-1 at 25, 60, and 100-mu-m, respectively. Models with significant luminosity evolution predict backgrounds about a factor of 4 greater than this minimum. Strong luminosity evolution of infrared-bright galaxies can be excluded based on the predicted high fractions of sources at z > 0.5 that do not appear in the many redshift surveys of infrared-bright galaxies conducted to date. The minimum predicted background should be detectable by COBE at 100-mu-m and might be detected at 60-mu-m. COBE will probably not detect the 25-mu-m background. The next generation of space missions (e.g., ISO and SIRTF) will easily detect and characterize the evolution of infrared-bright star-forming galaxies. C1 CALTECH,DIV PHYS MATH & ASTRON,PASADENA,CA 91125. CALTECH,CTR INFRARED PROC & ANAL,PASADENA,CA 91125. RP HACKING, PB (reprint author), JET PROP LAB,CTR INFRARED PROC & ANAL,MS 100-22,PASADENA,CA 91125, USA. NR 23 TC 43 Z9 43 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 1991 VL 367 IS 2 BP L49 EP L53 DI 10.1086/185929 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET684 UT WOS:A1991ET68400003 ER PT J AU TURNER, MS WATKINS, R WIDROW, LM AF TURNER, MS WATKINS, R WIDROW, LM TI MICROWAVE DISTORTIONS FROM COLLAPSING DOMAIN-WALL BUBBLES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC BACKGROUND RADIATION; COSMOLOGY; EARLY UNIVERSE ID RADIATION; UNIVERSE AB It has been suggested that large-scale structure can be seeded by a postrecombination phase transition that produces soft domain walls. We find that oscillating domain-wall bubbles produce a distinctive signature on the microwave sky: hot and cold spots with amplitude characterized by G-sigma-H0(-1) (sigma is the surface tension of the wall). These fluctuations are non-Gaussian and offer a powerful probe of such models. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV TORONTO,CANADIAN INST THEORET ASTROPHYS,TORONTO M5S 1A1,ONTARIO,CANADA. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138. RP TURNER, MS (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NAT ACCELERATOR LAB,MS 209,POB 500,BATAVIA,IL 60510, USA. NR 24 TC 25 Z9 25 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 1991 VL 367 IS 2 BP L43 EP L47 DI 10.1086/185928 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET684 UT WOS:A1991ET68400002 ER PT J AU GURZADYAN, GA KONDO, Y OHANESYAN, JB TERZIAN, Y PEREZ, MR AF GURZADYAN, GA KONDO, Y OHANESYAN, JB TERZIAN, Y PEREZ, MR TI A COOL GIANT WITH A CIRCUMSTELLAR CLOUD SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article ID STELLAR AB The IUE spectrum of the star HD 139521, a giant of class G8III is obtained and based on the analysis of the narrow structure of 2795 (k) and 2803 (h) Mg II emission profiles, the existence of a circumstellar cloud around the giant star is assumed. This conclusion is confirmed also by the anomaly of the small observed power of the doublet Mg II emission at 2800. The absorption cores on the peaks of the emission profiles Mg II k and h are mainly of interstellar origin and only partly - due to self-absorption in the star's chromosphere. C1 NASA,GODDARD SPACE FLIGHT CTR,ILIE OBSERV,GREENBELT,MD 20771. CORNELL UNIV,DEPT ASTRON,ITHACA,NY 14853. CORNELL UNIV,NAIC,ITHACA,NY 14853. RP GURZADYAN, GA (reprint author), ACAD SCI ARSSR,BYURAKAN ASTROPHYS OBSERV,ASHTARAK,ARMENIA,USSR. NR 13 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. PD FEB PY 1991 VL 176 IS 1 BP 61 EP 68 DI 10.1007/BF00643077 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE478 UT WOS:A1991FE47800006 ER PT J AU MANNHEIM, PD AF MANNHEIM, PD TI POTENTIAL SIGNAL FOR BLACK-HOLE FORMATION SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Letter C1 UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06268. RP MANNHEIM, PD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, 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. PD FEB PY 1991 VL 176 IS 2 BP 323 EP 323 DI 10.1007/BF00646707 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FH705 UT WOS:A1991FH70500011 ER PT J AU FORTNEY, SM HYATT, KH DAVIS, JE VOGEL, JM AF FORTNEY, SM HYATT, KH DAVIS, JE VOGEL, JM TI CHANGES IN BODY-FLUID COMPARTMENTS DURING A 28-DAY BED REST SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID HEAD-DOWN TILT; BEDREST AB The extravscular fluid responses to real or simulated space-flight are not well-documented. In this study serial isotape measurements were used to obtain measurments of the body fluid responses of 10 22-29-year-old men during 28 d of simulated microgravity (bed rest). The subjects were maintained on a controlled metabolic diet for 7 d before the study, during 14 d of ambulatory control, 28 d of horixontal bed rest, and 14 d of ambultant recovery. Fluid compartments were measured on control days 1 and 9, bed rest days 2, 14, and 28, and recovery days 7 and 14. By day 2 of bed rest, plasma volume (PV) and extra-cellular volume (ECV) decreased significantly by an average 209 and 533 ml, respectively. Red cell volume (RCV) and total body water (TBW) decreased more slowly, with average losses of 128 and 1,316 ml, respectively, after 28 d of bed rest. Early in the bed rest, TBW loss was mostly from the ECV. Therafter, the TBW deficit was derived from the intracellular compartment, which decreased an average of 838 ml after 28 d. These results suggest losses from all fluid compartments during bed rest, with no evidence of restoration of ECV after 1-2 weeks. RP FORTNEY, SM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,MAIL CODE SD-5,HOUSTON,TX 77058, USA. NR 31 TC 57 Z9 60 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD FEB PY 1991 VL 62 IS 2 BP 97 EP 104 PG 8 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA EV191 UT WOS:A1991EV19100001 PM 2001223 ER PT J AU LEE, AT AF LEE, AT TI AIRCREW DECISION-MAKING BEHAVIOR IN HAZARDOUS WEATHER AVOIDANCE SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID PERFORMANCE AB In-flight encounters with hazardous weather represent one of the most significant safety issues in civil aviation operations. Aircrew judgment is often cited as the probable cause of incidents and accidents involving weather, although lack of information is also a factor. The present study examines how information, presented at different times and in different forms, affects the awareness and decision-making behavior of aircrews in a flight simulation study of a recent microburst/windshear incident. In order to examine the influence of enhanced information transfer on aircrew behavior, intracrew communications and approach-to-land decisions were evaluated with conventional ATC communications and with automated cockpit alerting and display of weather information. Results of the study revealed that aircrews provided only with conventional ATC transmissions of weather information had difficulty discriminating conditions conducive to microburst events from less hazardous windshear events. Improved situation awareness for microburst events was found when ground-based convective weather information was provided in real time to aircrews. Avoidance decision-making was found to be less efficient with conventional ATC alert transmissions when compared to the performance of crews provided with visual display of microburst events. The importance of information transfer on aircrew situation awareness and decision-making in hazardous weather avoidance is discussed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 7 TC 1 Z9 1 U1 0 U2 4 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 1991 VL 62 IS 2 BP 158 EP 161 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA EV191 UT WOS:A1991EV19100011 PM 2001213 ER PT J AU LUDWIG, DA CONVERTINO, VA AF LUDWIG, DA CONVERTINO, VA TI A STATISTICAL NOTE ON THE REDUNDANCY OF 9 STANDARD BAROREFLEX PARAMETERS SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Note AB An accepted method for measuring the responsiveness of the carotid-cardiac baroreflex to arterial pressure changes is to artificially stimulate the baroreceptors in the neck with a pressureized neck chamber. Nine physiological responses to this type of stimulation are quantified and used as indicators of the baroreflex response function. Thirty male humans between the ages of 27 and 46 underwent the carotid-cardiac baroreflex test. The data for the nine response parameters were analyzed by principle component factor analysis. The results indicated that 92.5% of the total variance across all nine parameters could be explained in four dimensions. The first two dimensions reflected location points for R-R interval and carotid distending pressure, respectively. The third factor was composed of measures reflecting the gain (responsiveness) of the reflex. The fourth dimension was the ratio of baseline R-R interval to the maximal R-R interval response during simulated hypertension. The data suggest that the analysis of all nine baroreflex parameters is likely to be redundant and researchers should account for these redundancies either in their analyses or conclusions. C1 NASA,BIOMED OPERAT & RES OFF,KENNEDY SPACE CTR,FL. RP LUDWIG, DA (reprint author), UNIV N CAROLINA,DEPT MATH & STAT,383 BRYAN BLDG,GREENSBORO,NC 27412, USA. NR 11 TC 12 Z9 12 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 1991 VL 62 IS 2 BP 172 EP 175 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA EV191 UT WOS:A1991EV19100014 PM 2001216 ER PT J AU WELLER, RA DONELAN, MA BRISCOE, MG HUANG, NE AF WELLER, RA DONELAN, MA BRISCOE, MG HUANG, NE TI RIDING THE CREST - A TALE OF 2 WAVE EXPERIMENTS SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SURFACE GRAVITY-WAVES; ENERGY-SPECTRA; PHYSICAL BASIS; CONTOUR RADAR; OCEAN; WIND; SPECTROMETER; VELOCITY; PRESSURE; LAYER AB This paper gives a general overview of two ocean wave experiments. The experimental goals of the Surface Wave Processes Program (SWAPP) and of the Surface Wave Dynamics Experiment (SWADE) are quite different but complementary. In general terms, SWAPP is focused on local processes: principally wave breaking, upper mixed layer dynamics, and microwave and acoustic signatures of wave breaking. SWADE, on the other hand, is concerned primarily with the evolution of the directional wave spectrum in both time and space, improved understanding of wind forcing and wave dissipation, the effect of waves on the air-sea coupling mechanisms, and the radar response of the surface. Both programs acknowledge that wave dissipation is the weakest link in our understanding of wave evolution on the ocean. SWAPP takes a closer look at wave dissipation processes directly, while SWADE, with the use of fully non-linear (third generation) wave models and carefully measured wind forcing, provides an opportunity to study the effect of dissipation on spectral evolution. Both programs involve many research platforms festooned with instruments and large teams of scientists and engineers gathering and analyzing huge datasets. The success of SWAPP and SWADE will be measured in the degree to which the results can be integrated into a far more complete picture than we have had heretofore of interfacial physics, wave evolution, and mixed layer dynamics. C1 ENVIRONM CANADA,CANADA CTR INLAND WATERS,NATL WATER RES INST,BURLINGTON L7R 4A6,ONTARIO,CANADA. OFF NAVAL RES,ARLINGTON,VA 22217. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP WELLER, RA (reprint author), WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543, USA. NR 29 TC 39 Z9 39 U1 0 U2 0 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 1991 VL 72 IS 2 BP 163 EP 183 DI 10.1175/1520-0477(1991)072<0163:RTCATO>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FC269 UT WOS:A1991FC26900001 ER PT J AU NEUHAUSER, D JUDSON, RS JAFFE, RL BAER, M KOURI, DJ AF NEUHAUSER, D JUDSON, RS JAFFE, RL BAER, M KOURI, DJ TI TOTAL INTEGRAL REACTIVE CROSS-SECTIONS FOR F+H-2-]HF+H - COMPARISON OF CONVERGED QUANTUM, QUASI-CLASSICAL TRAJECTORY AND EXPERIMENTAL RESULTS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACE; WAVE-PACKET APPROACH; DEPENDENT SCHRODINGER-EQUATION; TRANSITION-STATE-THEORY; SCATTERING CALCULATIONS; F+H2 REACTION; MOLECULAR-BEAM; F+H2->HF+H; DYNAMICS; PROBABILITIES AB We report converged quantum total integral reactive cross sections for the reaction F + H-2 --> HF + H, for initial rotational states j(i) = 0 and 1, using a time-dependent method. Our results are compared to classical results and to the experimental results of Neumark et al. Strong quantum effects are found in the threshold region for both initial states; i.e. in the dependence of the reaction on initial state for low energies. The classical results agree better with experiment than to the quantum results; this appears to be due to errors in the potential used. C1 SANDIA NATL LABS, CTR COMP ENGN, LIVERMORE, CA 94550 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. SOREQ NUCL RES CTR, DEPT THEORET PHYS & APPL MATH, IL-70600 YAVNE, ISRAEL. UNIV HOUSTON, DEPT PHYS, HOUSTON, TX 77204 USA. UNIV HOUSTON, DEPT CHEM, HOUSTON, TX 77204 USA. RP PRINCETON UNIV, DEPT CHEM, PRINCETON, NJ 08544 USA. OI Judson, Richard/0000-0002-2348-9633 NR 42 TC 78 Z9 78 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 1 PY 1991 VL 176 IS 6 BP 546 EP 550 DI 10.1016/0009-2614(91)90253-6 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EX468 UT WOS:A1991EX46800010 ER PT J AU THOMPSON, AM STEWART, RW AF THOMPSON, AM STEWART, RW TI HOW CHEMICAL-KINETICS UNCERTAINTIES AFFECT CONCENTRATIONS COMPUTED IN AN ATMOSPHERIC PHOTOCHEMICAL MODEL SO CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS LA English DT Article ID HYDROGEN-PEROXIDE; OZONE; PERTURBATIONS; SENSITIVITY; PROPAGATION; RATES AB Tropospheric photochemical models are used increasingly as predictive tools to assess the chemical response of the lower atmosphere to changes in physical and chemical conditions which influence trace species distributions. Among the many uncertainties in the modeling process are imprecisions in reaction rate data used in formulating model continuity equations. In this paper we evaluate the propagation of these kinetics uncertainties to computed species distributions in a photochemical model. A one-dimensional kinetics-diffusion model having 72 reactions among 24 species is used. Non-chemical sources and initial background concentrations are chosen to be representative of clean continental mid-latitude air. Chemical reaction rate data are mostly those of the NASA Kinetics Evaluation Panel No. 8 (1987) and include imprecisions in photolysis rates and binary and ternary reactions. A Monte Carlo technique is used to estimate uncertainties in computed concentrations due to the given rate uncertainties. We compute uncertainties in odd hydrogen species (the radicals OH and HO2) and in hydrogen peroxide ranging from 22-41%. Uncertainties for O3 and CO are, respectively, 17% and 30%. Odd nitrogen uncertainties range from 18% for NO to 72% for N2O5. The smallest uncertainty is that for nitric acid at 6%, but this is neglecting uncertainties in physical sources and sinks, such as precipitation scavenging. The uncertainty in OH (31%) is important when using the model to predict tropospheric oxidant levels because OH determines the lifetime of numerous naturally and anthropogenically emitted trace gases. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 14 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7439 J9 CHEMOMETR INTELL LAB JI Chemometrics Intell. Lab. Syst. PD FEB PY 1991 VL 10 IS 1-2 BP 69 EP 79 DI 10.1016/0169-7439(91)80035-O PG 11 WC Automation & Control Systems; Chemistry, Analytical; Computer Science, Artificial Intelligence; Instruments & Instrumentation; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Automation & Control Systems; Chemistry; Computer Science; Instruments & Instrumentation; Mathematics GA FC580 UT WOS:A1991FC58000009 ER PT J AU PUTCHA, L CINTRON, NM TIETZE, KJ HUNTER, RP PARISE, CM BAKER, HE VANDERPLOEG, JM AF PUTCHA, L CINTRON, NM TIETZE, KJ HUNTER, RP PARISE, CM BAKER, HE VANDERPLOEG, JM TI SALIVARY PHARMACODYNAMICS OF SCOPOLAMINE SO CLINICAL PHARMACOLOGY & THERAPEUTICS LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. PHILADELPHIA COLL PHARM & SCI,PHILADELPHIA,PA 19104. KRUG LIFE SCI,HOUSTON,TX. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MOSBY-YEAR BOOK INC PI ST LOUIS PA 11830 WESTLINE INDUSTRIAL DR, ST LOUIS, MO 63146-3318 SN 0009-9236 J9 CLIN PHARMACOL THER JI Clin. Pharmacol. Ther. PD FEB PY 1991 VL 49 IS 2 BP 124 EP 124 PG 1 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA EZ620 UT WOS:A1991EZ62000004 ER PT J AU SNOWHARTER, C MYBURGH, K LEWIS, B CHARETTE, S ARNAUD, S MARCUS, R AF SNOWHARTER, C MYBURGH, K LEWIS, B CHARETTE, S ARNAUD, S MARCUS, R TI BONE-MINERAL DENSITY, MUSCLE STRENGTH, AND PHYSICAL-ACTIVITY IN MEN SO CLINICAL RESEARCH LA English DT Meeting Abstract C1 VET ADM MED CTR,GRECC,PALO ALTO,CA 94304. NASA,AMES RES CTR,MT VIEW,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SLACK INC PI THOROFARE PA 6900 GROVE RD, THOROFARE, NJ 08086 SN 0009-9279 J9 CLIN RES JI Clin. Res. PD FEB PY 1991 VL 39 IS 1 BP A100 EP A100 PG 1 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA ET786 UT WOS:A1991ET78600547 ER PT J AU KING, T AF KING, T TI YACC FOR EXPERT SYSTEMS SO DR DOBBS JOURNAL LA English DT Article C1 UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY SCI,LOS ANGELES,CA 90024. NASA,WJPL PLANETARY DATA SYST,WASHINGTON,DC 20546. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MILLER FREEMAN, INC PI SAN MATEO PA 411 BOREL AVE, SAN MATEO, CA 94402-3522 SN 1044-789X J9 DR DOBBS J JI Dr. Dobbs J. PD FEB PY 1991 VL 16 IS 2 BP 88 EP & PG 0 WC Computer Science, Software Engineering SC Computer Science GA EU291 UT WOS:A1991EU29100017 ER PT J AU KUMEI, Y WHITSON, PA SATO, A CINTRON, NM AF KUMEI, Y WHITSON, PA SATO, A CINTRON, NM TI HYPERGRAVITY SIGNAL TRANSDUCTION IN HELA-CELLS WITH CONCOMITANT PHOSPHORYLATION OF PROTEINS IMMUNOPRECIPITATED WITH ANTI-MICROTUBULE-ASSOCIATED PROTEIN ANTIBODIES SO EXPERIMENTAL CELL RESEARCH LA English DT Article ID SMOOTH-MUSCLE CELL; INOSITOL TRISPHOSPHATE; KINASE-C; CYTOSKELETON; LOCALIZATION; QUANTITATION; STIMULATION; EXPRESSION; INTERPHASE; MESSENGER C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. RP KUMEI, Y (reprint author), TOKYO MED & DENT UNIV,FAC DENT,DEPT BIOMAT SCI,1-5-45 YUSHIMA,BUNKYO KU,TOKYO 113,JAPAN. NR 38 TC 15 Z9 15 U1 1 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0014-4827 J9 EXP CELL RES JI Exp. Cell Res. PD FEB PY 1991 VL 192 IS 2 BP 492 EP 496 DI 10.1016/0014-4827(91)90068-6 PG 5 WC Oncology; Cell Biology SC Oncology; Cell Biology GA EU287 UT WOS:A1991EU28700021 PM 1703085 ER PT J AU RYDER, G BOGARD, D GARRISON, D AF RYDER, G BOGARD, D GARRISON, D TI PROBABLE AGE OF AUTOLYCUS AND CALIBRATION OF LUNAR STRATIGRAPHY SO GEOLOGY LA English DT Article ID APOLLO-15 AB Ar-39-Ar-40 analyses of three petrographically distinct, shocked Apollo 15 KREEP (i.e., high K, rare earth element, P, and other trace element contents) basalt samples demonstrate that a major impact event affected all three samples at about 2.1 Ga. The Copernican System craters Aristillus and Autolycus are to the north; a ray from one of them crosses the landing site and had been suggested prior to the Apollo 15 mission as a source of material that could be used to date these craters. Autolycus, the older of the two, is in a particularly appropriate terrain and is the most likely source of the 2.1 Ga heating and delivery event. With this calibration point, and if Autolycus really is a Copernican crater, the Copernican System lasted twice as long as has previously been suggested. Furthermore, the Moon was not subjected to a constant cratering rate over the past 3 b.y.; the average rate in the preceding Eratosthenian must have been twice that in the Copernican. C1 NASA,LYNDON B JOHNSON SPACE CTR,SN2,HOUSTON,TX 77058. LOCKHEED ESC,HOUSTON,TX 77058. RP RYDER, G (reprint author), LUNAR & PLANETARY INST,3303 NASA RD 1,HOUSTON,TX 77058, USA. NR 19 TC 29 Z9 29 U1 0 U2 1 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD FEB PY 1991 VL 19 IS 2 BP 143 EP 146 DI 10.1130/0091-7613(1991)019<0143:PAOAAC>2.3.CO;2 PG 4 WC Geology SC Geology GA EV835 UT WOS:A1991EV83500012 ER PT J AU DILEK, Y THY, P MOORES, EM AF DILEK, Y THY, P MOORES, EM TI EPISODIC DIKE INTRUSIONS IN THE NORTHWESTERN SIERRA-NEVADA, CALIFORNIA - IMPLICATIONS FOR MULTISTAGE EVOLUTION OF A JURASSIC ARC TERRANE SO GEOLOGY LA English DT Article ID HIGH-MAGNESIAN ANDESITES; SETOUCHI VOLCANIC BELT; TROODOS OPHIOLITE; SOUTHWEST JAPAN; ORIGIN; PETROGENESIS; GENESIS; CYPRUS AB In the northwestern Sierra Nevada, California, volcanic and plutonic rocks of the Smartville and Slate Creek complexes, both fragments of a Jurassic arc terrane, are tectonically juxtaposed against ophiolitic and marine rocks that represent late Paleozoic-early Mesozoic oceanic basement. This oceanic basement is intruded by Early Jurassic dikes that are coeval with hypabyssal and plutonic rocks within the Smartville and Slate Creek complexes. These dikes have geochemical characteristics reflecting a depleted and metasomatized source, as commonly observed in modern fore-arc settings and incipient volcanic arcs, and are interpreted to be the conduits for the Early Jurassic arc volcanism, which was built on and across the disrupted oceanic basement. Late Jurassic sheeted dikes intruding the Smartville complex have basaltic compositions compatible with an intra-arc or back-arc origin and indicate that a spreading event occurred within the arc in early Late Jurassic time. These interpretations support models for a complex multistage evolution via episodic magmatism and deformation within a single ensimatic Jurassic arc terrane west of the North American continent. C1 UNIV CALIF DAVIS,DEPT GEOL,DAVIS,CA 95616. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 22 TC 22 Z9 23 U1 1 U2 8 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD FEB PY 1991 VL 19 IS 2 BP 180 EP 184 DI 10.1130/0091-7613(1991)019<0180:EDIITN>2.3.CO;2 PG 5 WC Geology SC Geology GA EV835 UT WOS:A1991EV83500021 ER PT J AU ROBERTS, DA BAKER, DN KLIMAS, AJ BARGATZE, LF AF ROBERTS, DA BAKER, DN KLIMAS, AJ BARGATZE, LF TI INDICATIONS OF LOW DIMENSIONALITY IN MAGNETOSPHERIC DYNAMICS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SUBSTORMS AB Using three separate but related approaches, we examine the question of whether the dynamic response of the magnetosphere to the solar wind input may be described by a low-order system of equations. First, we determine that the dimension of the subset (the "attractor") in the high-dimensional magnetospheric phase space associated with the westward auroral electrojet (AL) index for some of the data sets compiled by Bargatze et al. [1985] is 4.0 +/- 0.2, seemingly independent of activity level. Second, direct modeling of the magnetosphere considering the bulk properties of the tail plasma leads to a system of equations that is similar to those previously reported as a dripping faucet model; here we focus specifically on the prediction of a natural frequency in this model. Finally, we identify a peak with the predicted frequency in power spectra of AL computed for intervals with both low and high activity. Peaks at other frequencies also appear in the spectra, and such resonances would be expected for a chaotic nonlinear oscillator. Combining these approaches we conclude that at least some aspects of magnetospheric dynamics may be meaningfully modeled by low-dimensional sets of equations. C1 UNIV CALIF LOS ANGELES,DEPT GEOPHYS & PLANETARY SCI,LOS ANGELES,CA 90024. RP ROBERTS, DA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERRESTRIAL PHYS LAB,GREENBELT,MD 20771, USA. RI Roberts, Dana/D-4625-2012 NR 15 TC 62 Z9 62 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 PY 1991 VL 18 IS 2 BP 151 EP 154 DI 10.1029/91GL00021 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EY529 UT WOS:A1991EY52900009 ER PT J AU WIENS, RC BURNETT, DS NEUGEBAUER, M PEPIN, RO AF WIENS, RC BURNETT, DS NEUGEBAUER, M PEPIN, RO TI SOLAR-WIND KRYPTON AND SOLID GAS FRACTIONATION IN THE EARLY SOLAR NEBULA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ABUNDANCES AB Krypton is the best candidate for determining limits on solid/gas fractionation in the early sun because of the smoothness of the odd-mass abundance curve in its mass region, which permits relatively precise interpolations of its abundance assuming no fractionation. Here we calculate the solar-system Kr abundance from solar-wind noble-gas ratios, determined previously by low-temperature oxidations of lunar ilmenite grains, normalized to Si by spacecraft solar-wind measurements. The estimated Kr-83 abundance of 4.1 +/- 1.5 per 10(6) Si atoms is within uncertainty of estimates assuming no fractionation, determined from CI-chondrite abundances of surrounding elements. This is significant because it is the first such constraint on solid/gas fractionation, though the large uncertainty only confines it to somewhat less than a factor of two. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. RP WIENS, RC (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. NR 26 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 FEB PY 1991 VL 18 IS 2 BP 207 EP 210 DI 10.1029/91GL00213 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EY529 UT WOS:A1991EY52900023 ER PT J AU RAY, JR MA, C RYAN, JW CLARK, TA EANES, RJ WATKINS, MM SCHUTZ, BE TAPLEY, BD AF RAY, JR MA, C RYAN, JW CLARK, TA EANES, RJ WATKINS, MM SCHUTZ, BE TAPLEY, BD TI COMPARISON OF VLBI AND SLR GEOCENTRIC SITE COORDINATES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTH AB The geocentric coordinates for 18 pairs of SLR and VLBI sites are compared. After a seven-parameter frame adjustment, the two coordinate sets have weighted rms differences of 15, 22, and 22 mm for X, Y, and Z, respectively, consistent with the formal errors being too small by a factor of about two. C1 NASA,GODDARD SPACE FLIGHT CTR,CODE 9269,GREENBELT,MD 20771. UNIV TEXAS,CTR SPACE RES,AUSTIN,TX 78712. NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,GREENBELT,MD 20771. RI Ma, Chopo/D-4751-2012 NR 8 TC 22 Z9 22 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 PY 1991 VL 18 IS 2 BP 231 EP 234 DI 10.1029/91GL00205 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EY529 UT WOS:A1991EY52900029 ER PT J AU TRAFTON, LM LESTER, DF RAMSEYER, TF SALAMA, F SANDFORD, SA ALLAMANDOLA, LJ AF TRAFTON, LM LESTER, DF RAMSEYER, TF SALAMA, F SANDFORD, SA ALLAMANDOLA, LJ TI A NEW CLASS OF ABSORPTION FEATURE IN IOS NEAR-INFRARED SPECTRUM SO ICARUS LA English DT Article ID GALILEAN SATELLITES; SULFUR-DIOXIDE; IO; SPECTROSCOPY; SURFACE C1 UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP TRAFTON, LM (reprint author), UNIV TEXAS,MCDONALD OBSERV,AUSTIN,TX 78712, USA. RI Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 27 TC 21 Z9 21 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 1991 VL 89 IS 2 BP 264 EP 276 DI 10.1016/0019-1035(91)90178-V PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX586 UT WOS:A1991EX58600005 PM 11538100 ER PT J AU MOSES, JI NASH, DB AF MOSES, JI NASH, DB TI PHASE-TRANSFORMATIONS AND THE SPECTRAL REFLECTANCE OF SOLID SULFUR - CAN METASTABLE SULFUR ALLOTROPES EXIST ON IO SO ICARUS LA English DT Article ID LIQUID SULFUR; IOS SURFACE; GALILEAN SATELLITES; MOLECULAR COMPOSITION; FLOWS; SO2; IRRADIATION; SCATTERING; VOLCANISM; STABILITY C1 SAN JUAN CAPISTRANO RES INST, SAN JUAN CAPISTRANO, CA 92675 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP MOSES, JI (reprint author), CALTECH, DIV PLANETARY SCI, PASADENA, CA 91125 USA. RI Moses, Julianne/I-2151-2013 OI Moses, Julianne/0000-0002-8837-0035 NR 114 TC 35 Z9 35 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD FEB PY 1991 VL 89 IS 2 BP 277 EP 304 DI 10.1016/0019-1035(91)90179-W PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX586 UT WOS:A1991EX58600006 ER PT J AU RAGES, K POLLACK, JB TOMASKO, MG DOOSE, LR AF RAGES, K POLLACK, JB TOMASKO, MG DOOSE, LR TI PROPERTIES OF SCATTERERS IN THE TROPOSPHERE AND LOWER STRATOSPHERE OF URANUS BASED ON VOYAGER IMAGING DATA SO ICARUS LA English DT Article ID INFRARED OBSERVATIONS; URANIAN SYSTEM; LINE-PROFILES; ATMOSPHERE; AEROSOLS; PLANETARY; RADIATION; SPECTRUM; NEPTUNE; METHANE C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. UNIV ARIZONA,TUCSON,AZ 85721. RP RAGES, K (reprint author), MYCOL INC,SUNNYVALE,CA 94087, USA. NR 34 TC 44 Z9 44 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 1991 VL 89 IS 2 BP 359 EP 376 DI 10.1016/0019-1035(91)90183-T PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX586 UT WOS:A1991EX58600010 ER PT J AU LANDRY, B ALLEN, M YUNG, YL AF LANDRY, B ALLEN, M YUNG, YL TI TROPOSPHERE STRATOSPHERE INTERACTIONS IN A ONE-DIMENSIONAL MODEL OF JOVIAN PHOTOCHEMISTRY SO ICARUS LA English DT Article ID CARBON-MONOXIDE; UPPER-ATMOSPHERE; VERTICAL-DISTRIBUTION; JUPITERS ATMOSPHERE; CO; ABUNDANCES; CONVECTION; SATURN; ETHANE; TITAN C1 CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109. RP LANDRY, B (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. FU NINDS NIH HHS [NSG-7376] NR 29 TC 17 Z9 17 U1 1 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 1991 VL 89 IS 2 BP 377 EP 383 DI 10.1016/0019-1035(91)90184-U PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EX586 UT WOS:A1991EX58600011 PM 11538101 ER PT J AU BARNES, NP ALLEN, RE AF BARNES, NP ALLEN, RE TI ROOM-TEMPERATURE DY-YLF LASER OPERATION AT 4.34 MU-M SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB A Dy:YLF laser, operating on the 6H11/2 to 6H13/2 transition at 4.34-mu-m, has been demonstrated. A solid-state laser operating at this wavelength is one of the longest wavelength solid-state lasers known. An investigation of this material includes both spectroscopic and laser results. Spectroscopic results include the measurements of the absorption spectra and the lifetimes of both the upper- and lower-lser manifolds. Laser results, obtained using a 1.73-mu-m Er:YLF pump laser, achieved a slope efficiency in excess of 0.05. C1 USN,RES LAB,WASHINGTON,DC 20375. RP BARNES, NP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 13 TC 46 Z9 47 U1 1 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD FEB PY 1991 VL 27 IS 2 BP 277 EP 282 DI 10.1109/3.78231 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA FG745 UT WOS:A1991FG74500015 ER PT J AU CAROGLANIAN, A WEBB, KJ AF CAROGLANIAN, A WEBB, KJ TI STUDY OF CURVED AND PLANAR FREQUENCY-SELECTIVE SURFACES WITH NONPLANAR ILLUMINATION SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article AB A locally planar technique (LPT) is investigated for determining the forward scattered field from a generally shaped inductive frequency-selective surface (FSS) with nonplanar illumination. The results of an experimental study are presented to assess the LPT accuracy. The effects of a nonplanar incident field are determined by comparing the LPT numerical results with a series of experiments with the feed source placed at varying distances from the planar FSS. The limitations of the LPT model due to surface curvature is investigated by an experimental study of the scattered fields from a set of hyperbolic cylinders of different curvatures. From these comparisons, guidelines for applying the locally planar technique are developed. C1 PURDUE UNIV,SCH ELECT ENGN,W LAFAYETTE,IN 47907. RP CAROGLANIAN, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DIV NETWORKS,RF SYST SECT,CODE 5312,GREENBELT,MD 20771, USA. NR 6 TC 10 Z9 10 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 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD FEB PY 1991 VL 39 IS 2 BP 211 EP 217 DI 10.1109/8.68184 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA EV694 UT WOS:A1991EV69400013 ER PT J AU GERONDAKIS, GG AF GERONDAKIS, GG TI GET AWAY SPECIAL (GAS) EDUCATIONAL APPLICATIONS OF SPACE-FLIGHT SO IEEE TRANSACTIONS ON EDUCATION LA English DT Article AB The National Aeronautics and Space Administration (NASA) has established the Small Self-Contained Payloads (SSCP) Program, commonly known as the Get Away Special (GAS) Program. This program provides the means for anyone who wishes the opportunity to place a small self-contained experimental payload on the Space Shuttle at a very low cost. These payloads must be of peaceful intent and be an engineering and/or science endeavor. The GAS community consists of experimentals from all walks of life and from many nations around the world. One of the prime objectives of the GAS program is to foster enthusiasm in the younger generation in the use of space. This paper looks at the history of the program from its initiation through the development phase, its interaction with the educational community, the education-industry relationship, and some educational objectives. This paper addresses the programmatic and technical relationships that are established between NASA and the GAS customer, and ends with a brief look into the future. C1 NASA,GODDARD SPACE FLIGHT CTR,DIV SPECIAL PAYLOADS,GREENBELT,MD 20771. NR 0 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 0018-9359 J9 IEEE T EDUC JI IEEE Trans. Educ. PD FEB PY 1991 VL 34 IS 1 BP 5 EP 10 DI 10.1109/13.79871 PG 6 WC Education, Scientific Disciplines; Engineering, Electrical & Electronic SC Education & Educational Research; Engineering GA FG519 UT WOS:A1991FG51900002 ER PT J AU SADIN, SR AF SADIN, SR TI NASAS UNIVERSITY ENGINEERING PROGRAMS SO IEEE TRANSACTIONS ON EDUCATION LA English DT Article AB While NASA has supported engineering research at the universities for many years, much of it has been along prescribed paths of investigation. The objective of a newly emerging element of the university engineering programs is to provide a more autonomous element that will enhance and broaden the capabilities in academia, enabling them to participate more effectively in the U.S. civil space program. These programs are an integral part of national policy and the strategy to rebuild the United States space research and technology base; they propose to remedy the decline in qualified space engineers by making long-term commitments to universities aspiring to play a strong engineering role in the civil space program. These programs utilize technical monitors at NASA centers to foster collaborative arrangements, exchange of personnel, and the sharing of facilities between NASA and the universities. The elements include: the University Advanced Space Design program, which funds advanced systems study courses at the senior and graduate levels; the University Space Engineering Research Centers and the Centers for the Commercial Development of Space that support cross-disciplinary research; the Outreach flight experiments program that offers engineering research opportunities to universities; a university investigator's research program that provides grants to individuals with outstanding credentials; and the National Space Grant College and Fellowship Program. C1 UNIV SPACE RES ASSOC,STRATEG DEV,WASHINGTON,DC 20024. RP SADIN, SR (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 5 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 0018-9359 J9 IEEE T EDUC JI IEEE Trans. Educ. PD FEB PY 1991 VL 34 IS 1 BP 31 EP 35 DI 10.1109/13.79876 PG 5 WC Education, Scientific Disciplines; Engineering, Electrical & Electronic SC Education & Educational Research; Engineering GA FG519 UT WOS:A1991FG51900007 ER PT J AU PEREZ, RM CONROY, BL AF PEREZ, RM CONROY, BL TI CALORIMETRIC OUTPUT POWER MEASUREMENTS ON A CW 20-KW 7.16 GHZ MICROWAVE TRANSMITTER SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Note AB The calorimetric measurement of the output level of high power microwave transmitters has traditionally required knowing the thermal constants of the cooling medium to a high degree of precision. This paper describes a calorimetric measurement technique developed for NASA's Deep Space Network (DSN) transmitters that does not require data on the coolant's thermal parameters. Calibration of the measurement system is achieved by measuring the DC input power to the klystron and relating coolant temperature increases to this known power dissipation. RP PEREZ, RM (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 4 TC 1 Z9 1 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1991 VL 40 IS 1 BP 49 EP 51 DI 10.1109/19.69953 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EV911 UT WOS:A1991EV91100015 ER PT J AU NGO, DM WILSON, JW FOGARTY, TN BUCK, WW AF NGO, DM WILSON, JW FOGARTY, TN BUCK, WW TI A NUCLEAR FRAGMENTATION ENERGY DEPOSITION MODEL SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article ID PROTONS; SILICON; SPECTRA AB A formalism for target fragment transport is presented with application to energy loss spectra in thin silicon devices. A nuclear data base is recommended that agrees well with the measurements of McNulty et al. using surface barrier detectors. High-energy events observed by McNulty et al., which are not predicted by intranuclear cascade models, are well represented by the present work. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. AT&T BELL LABS,ALLENTOWN,PA 18103. HAMPTON UNIV,DEPT PHYS,HAMPTON,VA 23668. RP NGO, DM (reprint author), OLD DOMINION UNIV,DEPT PHYS,NORFOLK,VA 23529, USA. NR 22 TC 7 Z9 7 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1991 VL 38 IS 1 BP 2 EP 8 DI 10.1109/23.64634 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ET829 UT WOS:A1991ET82900002 ER PT J AU TARN, TJ BEJCZY, AK YUN, XP LI, ZF AF TARN, TJ BEJCZY, AK YUN, XP LI, ZF TI EFFECT OF MOTOR DYNAMICS ON NONLINEAR FEEDBACK ROBOT ARM CONTROL SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article AB A nonlinear feedback robot controller that incorporates the robot manipulator dynamics as well as the robot joint motor dynamics is proposed in this paper. The manipulator dynamics and the motor dynamics are coupled to obtain a third-order dynamic model, and differential geometric control theory is applied to produce a linearized and decoupled robot controller. The derived robot controller operates in the robot task space, thus eliminating the need for decomposition of motion commands into robot joint space commands. Computer simulations are performed to verify the feasibility of the proposed robot controller. The controller is further experimentally evaluated on the PUMA 560 robot arm. The experiments show that the proposed controller produces good trajectory tracking performances and is robust in the presence of model inaccuracies. Compared with a nonlinear feedback robot controller based on the manipulator dynamics only, the proposed robot controller yields conspicuously improved performance. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV PENN,DEPT COMP & INFORMAT SCI,PHILADELPHIA,PA 19104. WASHINGTON UNIV,SCH MED,EDWARD MALLINCKRODT INST RADIOL,PHYS SECT,ST LOUIS,MO 63110. RP TARN, TJ (reprint author), WASHINGTON UNIV,DEPT SYST SCI & MATH,ST LOUIS,MO 63130, USA. NR 12 TC 152 Z9 161 U1 0 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD FEB PY 1991 VL 7 IS 1 BP 114 EP 122 DI 10.1109/70.68075 PG 9 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA EV619 UT WOS:A1991EV61900011 ER PT J AU PAL, A PAL, SK AF PAL, A PAL, SK TI EFFECT OF WRONG SAMPLES ON THE CONVERGENCE OF LEARNING-PROCESSES SO INFORMATION SCIENCES LA English DT Article RP PAL, A (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 10 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0020-0255 J9 INFORM SCIENCES JI Inf. Sci. PD FEB PY 1991 VL 53 IS 3 BP 191 EP 201 PG 11 WC Computer Science, Information Systems SC Computer Science GA EH788 UT WOS:A1991EH78800001 ER PT J AU EDWARDS, TA AF EDWARDS, TA TI EFFECT OF EXHAUST PLUME AFTERBODY INTERACTION ON INSTALLED SCRAMJET PERFORMANCE SO JOURNAL OF AIRCRAFT LA English DT Article AB An upwind, implicit Navier-Stokes computer program has been applied to hypersonic exhaust plume/afterbody flowfields. The capability to solve typical geometries at hypersonic speeds, including an interacting exhaust plume, has been demonstrated on a simplified nozzle/afterbody model. Comparison of the numerical results with available experimental data shows good agreement in all cases investigated. For moderately underexpanded jets, afterbody forces were found to vary linearly with the nozzle exit presure. Coupling a species continuity equation to the Navier-Stokes equations enabled calculations that indicated that exhaust gases with low isentropic exponents gamma contribute up to 25% more force than high gamma exhaust gases. Nozzle geometry was also found to have a large influence on the afterbody flowfield. RP EDWARDS, TA (reprint author), NASA,AMES RES CTR,APPL COMPUTAT FLUIDS BRANCH,MOFFETT FIELD,CA 94035, 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD FEB PY 1991 VL 28 IS 2 BP 123 EP 130 DI 10.2514/3.46000 PG 8 WC Engineering, Aerospace SC Engineering GA FM752 UT WOS:A1991FM75200004 ER PT J AU KWON, JH LEE, JH WILLIAMS, MD AF KWON, JH LEE, JH WILLIAMS, MD TI FAR-FIELD PATTERN OF A COHERENTLY COMBINED BEAM FROM LARGE-SCALE LASER DIODE-ARRAYS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TRAVELING-WAVE AMPLIFIER; HIGH-POWER; OPERATION AB The far-field pattern of a large-scale amplifier array (LSAA) consisting of a large number (2000) of diode laser amplifiers is numerically sumulated, and the power collection efficiencies are determined. Random distributions of phase mismatches, misorientations, and element failures in the LSAA system are considered. Phase mismatches and misorientations of the element amplifiers are found to be the most critical parameters of those affecting the power-collection efficiency. Errors of 0.2-lambda and 25% for phase and diffraction angle, respectively, cause a 10% reduction in power-collection efficiency. The results are used to evaluate the concept of space-laser power transmission. It was found that an overall transmission efficiency of 80% could be realized with a 5-m-diam. receiver at a distance of 10 000 km when an LSAA transmitter 6 m in diam. is aimed with state-of-the-art pointing accuracy. C1 MIAMI UNIV,DEPT PHYS,OXFORD,OH 45066. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 14 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1177 EP 1182 DI 10.1063/1.347301 PG 6 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100009 ER PT J AU KUMMEROW, C HAKKARINEN, IM PIERCE, HF WEINMAN, JA AF KUMMEROW, C HAKKARINEN, IM PIERCE, HF WEINMAN, JA TI DETERMINATION OF PRECIPITATION PROFILES FROM AIRBORNE PASSIVE MICROWAVE RADIOMETRIC MEASUREMENTS SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometeor density. RP KUMMEROW, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,SEVERE STORMS BRANCH,CODE 612,GREENBELT,MD 20771, USA. NR 0 TC 35 Z9 35 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD FEB PY 1991 VL 8 IS 1 BP 148 EP 158 DI 10.1175/1520-0426(1991)008<0148:DOPPFA>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA FC515 UT WOS:A1991FC51500013 ER PT J AU BARNES, LA ROSI, M BAUSCHLICHER, CW AF BARNES, LA ROSI, M BAUSCHLICHER, CW TI AN ABINITIO STUDY OF FE(CO)1, FE(CO)5, AND CR(CO)6 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-METAL-CARBONYLS; GAUSSIAN-BASIS SETS; ELECTRONIC-STRUCTURE; GAS-PHASE; CHROMIUM HEXACARBONYL; NEUTRON-DIFFRACTION; THEORETICAL ASPECTS; MOLECULAR-STRUCTURE; IRON PENTACARBONYL; NEGATIVE-IONS AB Ab initio calculations have been performed for Cr(CO)6 and Fe(CO)n, n = 1,5. Basis sets of better than double zeta quality are used and correlations is included using the modified coupled-pair functional method. The computed geometries and force constants are in reasonable agreement with experiment. The sequential bond dissociation energies of CO from Fe(CO)5 are estimated to be: 39, 31, 25, 22, and > 5 kcal/mol. We note that the first bond dissociation energy is relative to the singlet ground state of Fe(CO)5 and the lowest singlet state of Fe(CO)4, whereas the second is relative to the ground triplet states of Fe(CO)4 and Fe(CO)3. In addition, the binding energy for Fe-CO would be modified to 18 kcal/mol if dissociation occurred to the Fe(5F) excited state asymptote. The CO binding energies for Fe and Cr are found to be in poorer agreement with experiment than those found in a previous study on Ni(CO)4. The origins of this difference are discussed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Rosi, Marzio/L-5748-2015 OI Rosi, Marzio/0000-0002-1264-3877 NR 66 TC 150 Z9 150 U1 1 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1991 VL 94 IS 3 BP 2031 EP 2039 DI 10.1063/1.459924 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600041 ER PT J AU CHATFIELD, DC TRUHLAR, DG SCHWENKE, DW AF CHATFIELD, DC TRUHLAR, DG SCHWENKE, DW TI BENCHMARK CALCULATIONS OF THERMAL-REACTION RATES .1. QUANTAL SCATTERING-THEORY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-STATE THEORY; RATE CONSTANTS; VARIATIONAL-METHODS; CROSS-SECTIONS; CONVERGENCE; MATRIX; H-3 AB The thermal rate coefficient for the prototype reactions H + H-2 -->H2 + H with zero total angular momentum is calculated by summing, averaging, and numerically integrating state-to-state reaction probabilities calculated by time-dependent quantum-mechanical scattering theory. The results are very carefully converged with respect to all numerical parameters in order to provide high-precision benchmark results for confirming the accuracy of new methods and testing their efficiency. C1 UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. RI schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 24 TC 19 Z9 19 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1991 VL 94 IS 3 BP 2040 EP 2044 DI 10.1063/1.459925 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600042 ER PT J AU BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H AF BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H TI THE BINDING-ENERGIES OF CU+-(H2O)N AND CU+-(NH3)N (N = 1-4) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN BASIS FUNCTIONS; TRANSITION-METAL IONS; ATOMIC BASIS SETS; FIRST-ROW ATOMS; MOLECULAR CALCULATIONS; GAS-PHASE; CONTRACTION; ORBITALS; WATER; HYDRATION AB The successive binding energies of up to four H2O and NH3 ligands to CU+ are computed at the self-consistent-field and modified coupled-pair functional levels. The most stable structures are those where all ligands are equivalent. Replacing Cu+ by a point charge gives binding energies that are in good agreement with ab initio and experimental results, and is consistent with bonding that is largely charge dipole in nature. About two-thirds of the large reduction in ligand binding energy between the second and third ligand is due to ligand-ligand repulsion, while one-third is due to increased metal-ligand repulsion resulting from a loss of sd-sigma hybridization. The first and second ligand binding energies increase substantially at the correlated level due to improved description of sd-sigma hybridization. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 20 TC 157 Z9 157 U1 1 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1991 VL 94 IS 3 BP 2068 EP 2072 DI 10.1063/1.459929 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600046 ER PT J AU SALPEKAR, SA RAJU, IS OBRIEN, TK AF SALPEKAR, SA RAJU, IS OBRIEN, TK TI STRAIN-ENERGY-RELEASE RATE ANALYSIS OF DELAMINATION IN A TAPERED LAMINATE SUBJECTED TO TENSION LOAD SO JOURNAL OF COMPOSITE MATERIALS LA English DT Article AB A tapered composite laminate subjected to tension load was analyzed using the finite element method. The {[0(7)/(+/- 45)]/up[(+/- 45)3]/[0/(+/- 45)/0]}s glass/epoxy laminate has a (+/- 45)3 group of plies dropped in three distinct steps, each 20 ply-thicknesses apart, thus forming a taper angle of 5.71 degrees. Steep gradients of interlaminar normal and shear stress on a potential delamination interface suggest the existence of stress singularities at the points of material and geometric discontinuities created by the internal plydrops. The delamination was assumed to initiate at the thin end of the taper on the -45/ + 45 interface indicated by the arrow in the laminate layup and the delamination growth was simulated in both directions, i.e., along the taper and into the thin region. The total strain-energy-release rate, G, and the mode I and mode II components of G, were computed at the delamination tips using the virtual crack closure technique. In addition, G was calculated from a global energy balance method. The strain-energy-release rate for a delamination growing into the thin laminate consisted predominantly of mode I (opening) component. For a delamination growing along the tapered region, the strain-energy-release rate was initially all mode I, but the proportion of mode I decreased with increase in delamination size until eventually total G was all mode II. The total G for both delamination tips increased with increase in delamination size, indicating that a delamination initiating at the end of the taper will grow unstably along the taper and into the thin laminate simultaneously. C1 USA AVIAT RES & TECHNOL ACT,NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP SALPEKAR, SA (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 10 TC 24 Z9 24 U1 1 U2 2 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0021-9983 J9 J COMPOS MATER JI J. Compos Mater. PD FEB PY 1991 VL 25 IS 2 BP 118 EP 141 PG 24 WC Materials Science, Composites SC Materials Science GA EY768 UT WOS:A1991EY76800001 ER PT J AU JOHNSON, EJ HYER, PV CULOTTA, PW BLACK, LR CLARK, IO TIMMONS, ML AF JOHNSON, EJ HYER, PV CULOTTA, PW BLACK, LR CLARK, IO TIMMONS, ML TI CHARACTERIZATION OF MOCVD FLUID-DYNAMICS BY LASER VELOCIMETRY SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID HORIZONTAL CYLINDER; REACTOR; CONVECTION; GAS AB The process of metalorganic chemical vapor deposition (MOCVD) is critically dependent on the fluid dynamics of the reacting and carrier gases. Quantitative understanding of the basic fluid dynamics associated with a reactor design is central to the application of engineering techniques to achieve design improvements in efficiency, bulk production and growth uniformity. A laser velocimetry (LV) system has been adapted specifically to acquire such quantitative information for the low Reynolds number mixed convective flows commonly encountered in MOCVD reactors. The instrument uses three color-separated wavelengths of an argon-ion laser to make three simultaneous independent orthogonal measurements of the flow field at specified interior locations. The technique is noninvasive, provides high spatial resolution, and is compatible with reactors operating at growth temperatures. The fluid dynamics of a horizontal MOCVD reactor used for GaAs growth were characterized by laser velocimetry measurements. The full three-component LV system was employed to determine a three-dimensional map of the flow field inside the quartz reactor vessel. Data have been obtained from the vessel both at room temperature and heated to growth temperature by RF induction. The two cases were compared to evaluate the effects of gravity-induced convection and buoyancy. Significant convective effects were found in the heated reactor, while fluidic switching effects were observed during room temperature operation. Instrumentation details and flow field measurements are presented. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RES TRIANGLE INST,RES TRIANGLE PK,NC 27709. NR 17 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 24 EP 30 DI 10.1016/0022-0248(91)90153-V PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300006 ER PT J AU KNUTESON, DJ FRIPP, AL WOODELL, GA DEBNAM, WJ NARAYANAN, R AF KNUTESON, DJ FRIPP, AL WOODELL, GA DEBNAM, WJ NARAYANAN, R TI OSCILLATION PHASE-RELATIONS IN A BRIDGMAN SYSTEM SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID CONVECTION; TRANSITION; TURBULENCE AB The thermal conditions under which convection in a tin melt undergoes the transition from steady flow to time-dependent flow are investigated. Previously, it has been shown that crystals that are directionally solidified from a time-dependent melt will have a larger defect density and increased change of compositional striations. Thus, it is important for this transition to be well characterized. The experimental results to be presented were obtained from a two-zone Bridgman furnace with a middle insulation zone. Thermocouples were placed on the axis and on the outer wall of a cylindrical vitreous silica tube which contained molten tin. The phase relations between temperature oscillations measured at different positions in the cell are discussed. Fourier transforms are used to investigate the increasing complexity of convection as the temperature gradient is increased. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV FLORIDA,DEPT CHEM ENGN,GAINESVILLE,FL 32611. NR 12 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 127 EP 132 DI 10.1016/0022-0248(91)90167-4 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300020 ER PT J AU BLACK, LR CLARK, IO FOX, BA JESSER, WA AF BLACK, LR CLARK, IO FOX, BA JESSER, WA TI MOCVD OF GAAS IN A HORIZONTAL REACTOR - MODELING AND GROWTH SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID GAS-PHASE AB Metalorganic chemical vapor deposition (MOCVD) of GaAs in a horizontal reactor was performed and the process mathematically modeled in two dimensions. Growth was performed at pressures of 1.0 and 0.1 atm. The mass flow rates of the reactants, trimethylgallium (TMG) and arsine, were held constant in all runs with the hydrogen carrier gas comprising the remainder of the flow. An advanced computational fluid dynamics code enhanced for chemically reacting non-isothermal flows was used to model the deposition process. Parameters used in the model included: reactor geometry and operating pressure; thermal boundary conditions; ratio of reactants; chemical reactions; total inlet gas flow rate; and molecular weights, thermal conductivities, heat capacities, viscosities, and binary diffusion coefficients of the gas-phase species. Densities were calculated from the ideal gas law. Heats of reaction were obtained from the enthalpies of formation of the individual species. A single surface reaction Ga(CH3)3+AsH3 --> GaAs(s)+3CH4 was assumed. Film thickness profiles predicted by the model were compared with those of the GaAs thin films grown in the modeled reactor. The predictions and data are in good agreement over the entire length of the deposition region for the low pressure and high flow rate run. At the lower flow rate and at atmospheric pressure, the model predicted much more uniform deposition profiles than were obtained experimentally. These results and possible explanations for the discrepancies between the model and the data will be presented. Work is in progress to refine the model by including additional chemical reactions, Soret diffusion, and three-dimensional simulations. C1 UNIV VIRGINIA,DEPT MAT SCI,CHARLOTTESVILLE,VA 22903. RP BLACK, LR (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. RI Schaff, William/B-5839-2009 NR 13 TC 10 Z9 10 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 241 EP 245 DI 10.1016/0022-0248(91)90185-8 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300038 ER PT J AU CLARK, IO FRIPP, AL JESSER, WA AF CLARK, IO FRIPP, AL JESSER, WA TI MOCVD MANIFOLD SWITCHING EFFECTS ON GROWTH AND CHARACTERIZATION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH AB The components of metalorganic chemical vapor deposition (MOCVD) supply manifolds have significant effects on the ability to rapidly introduce and exhaust growth materials. This in turn has direct bearing on the achievable heterojunction interface abruptness for a given manifold design. Research to quantify the effects of various manifold components on the switching speed has been performed with a combined modeling and experimental approach. An overview of the experimental investigation is reported. Manifold switching sections were incorporated in a manifold line instrumented with an atmospheric pressure sampling mass spectrometer. A constant flow rate of nitrogen was established in the manifold line to serve as the carrier gas. Into this flow, controlled concentration pulses of argon were introduced from one switching section at a time to model the transport of source gases. A square-wave generator was used to control the on-time of the source for both single and multiple pulse experiments. The results of the single pulse experiments are reported here. The sudden displacement of the valve seats in the air-actuated bellows valves was found to introduce significant pressure and concentration spikes. These spikes demonstrate the need to carefully resolve the effects of pressure and concentration on the measurement technique. For the mass spectrometer system, measurement artifacts occur due to the pressure pulses increasing the rate at which gas enters the sampling orifice. Similar measurement artifacts would be expected in any concentration measurement system which measures number density or which employs a sampling orifice. C1 UNIV VIRGINIA,DEPT MAT SCI,CHARLOTTESVILLE,VA 22903. RP CLARK, IO (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 3 TC 2 Z9 2 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 246 EP 251 DI 10.1016/0022-0248(91)90186-9 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300039 ER PT J AU SU, CH LEHOCZKY, SL SZOFRAN, FR AF SU, CH LEHOCZKY, SL SZOFRAN, FR TI DIRECTIONAL SOLIDIFICATION OF HGCDTE AND HGZNTE IN A TRANSVERSE MAGNETIC-FIELD SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID SILICON CRYSTAL-GROWTH; SEGREGATION AB Hg0.80Cd0.20Te crystals were grown vertically in a transverse magnetic field by directional solidification. The effects of a magnetic field on the nature of fluid flow in the melts were investigated by measuring compositional variations along the axial and radial directions of the grown ingots. Magnetic field effects were shown to be significant over the entire field range employed (i.e. 2 to 5 kG). The axial compositional profiles (determined by precision density measurements) showed an abrupt decrease in the mole fraction of CdTe when the field was applied. Radial compositional mapping by infrared transmission and X-ray energy dispersion spectrometry indicated that the solid-liquid interface evolved through three stages when the field was applied, i.e. from a radially symmetric concave interface to an off-center concave shape when the field was initially applied, then to a tilted plane, and, finally, to an off-center concave interface. The axial compositional profile of an Hg0.84Zn0.16Te ingot showed similar field effects. RP SU, CH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 24 TC 12 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 392 EP 400 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300062 ER PT J AU HEDIN, AE AF HEDIN, AE TI EXTENSION OF THE MSIS THERMOSPHERE MODEL INTO THE MIDDLE AND LOWER ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SCATTER RADAR MEASUREMENTS; TEMPERATURE; MESOPAUSE; BREAKING; DYNAMICS; LATITUDE AB The MSIS-86 empirical model has been revised in the lower thermosphere and extended into the mesosphere and lower atmosphere to provide a single analytic model for calculating temperature and density profiles representative of the climatological average for various geophysical conditions. Tabulations from the Handbook for MAP 16 are the primary guide for the lower atmosphere and are supplemented by historical rocket and incoherent scatter data in the upper mesosphere and lower thermosphere. Low-order spherical harmonics and Fourier series are used to describe the major variations throughout the atmosphere including latitude, annual, semiannual, and simplified local time and longitude variations. While month to month details cannot be completely represented, lower atmosphere temperature data are fit to an overall standard deviation of 3 K and pressure to 2%. Comparison with rocket and other data indicates that the model represents current knowledge of the climatological average reasonably well, although there is some conflict as to details near the mesopause. RP HEDIN, AE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,PLANETARY ATMOSPHER BRANCH,CODE 914,GREENBELT,MD 20771, USA. NR 31 TC 1649 Z9 1688 U1 8 U2 39 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 1991 VL 96 IS A2 BP 1159 EP 1172 DI 10.1029/90JA02125 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600010 ER PT J AU FENNELLY, JA TORR, DG RICHARDS, PG TORR, MR SHARP, WE AF FENNELLY, JA TORR, DG RICHARDS, PG TORR, MR SHARP, WE TI A METHOD FOR THE RETRIEVAL OF ATOMIC OXYGEN DENSITY AND TEMPERATURE PROFILES FROM GROUND-BASED MEASUREMENTS OF THE O+(2D - 2P) 7320-A TWILIGHT AIRGLOW SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID IONIZATION FREQUENCIES; PHOTOELECTRON FLUX; SOLAR CYCLE-21 AB This paper describes a technique for the retrieval of altitude profiles of the atomic oxygen concentration (n = [O]) and temperature (T) from ground-based measurements of the O+(2D - 2P) doublet at 7320 and 7320 angstrom in the twilight airglow. The technique is based on previously demonstrated knowledge that at solar zenith angles (SZA) characteristic of twilight conditions, the upper state of the 7320-angstrom doublet transition is produced by photoionization and photoelectron impact ionization of atomic oxygen and lost mainly by radiative decay, thereby providing a sensitive dependence on [O]. We apply inverse problem theory to retrieve the exospheric temperature (T-infinity), the atomic oxygen concentration at 120 km (n-120), the temperature at 120 km (T-120) and the temperature profile shape factor (S) using a Bates-Walker representation of n given approximately by n = (n-120T-120/T)exp[-z] where T = T-infinity - (T-infinity - T-120)exp[-S(h - h-120), z is the reduced height, and h is the altitude. The algorithm is tested and theoretically verified using synthetic data sets where random errors of measurements are characterized by Poisson noise due primarily to sky background. In the tests that we report here the solar EUV flux is specified. In a separate paper we will report how the solar EUV ionization rate can be independently derived from various twilight emissions. By comparing retrieved with known input values, it is demonstrated that for the altitude range 200 to 500 km the atomic oxygen concentration [O] can be retrieved with relative errors congruent-to 15% and systematic errors of about 25% if the solar EUV is given.. Sensitivity of the results to noise, sample size (degrees of freedom), and absolute calibration are quantitatively evaluated. In addition, to demonstrate the validity of the technique experimentally, we utilized the Atmosphere Explorer E (AE-E) in situ measurements of the solar EUV flux and [O], with the latter taken when perigee was over Arecibo on an occasion when the observatory airglow spectrometer was simultaneously measuring the 7320-angstrom emission from the ground during twilight. The results show excellent agreement with the measured [O] values which were approximately 50% lower than the mass spectrometer incoherent scatter (MSIS-86) model values at approximately 300 km on that day, thereby demonstrating the value of the method for monitoring day-to-day variations in [O] and the temperature. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. RP FENNELLY, JA (reprint author), UNIV ALABAMA,CTR SPACE PLASMA & AERONOM RES,HUNTSVILLE,AL 35899, USA. NR 23 TC 10 Z9 10 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1263 EP 1273 DI 10.1029/90JA01593 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600018 ER PT J AU PROLSS, GW BRACE, LH MAYR, HG CARIGNAN, GR KILLEEN, TL KLOBUCHAR, JA AF PROLSS, GW BRACE, LH MAYR, HG CARIGNAN, GR KILLEEN, TL KLOBUCHAR, JA TI IONOSPHERIC STORM EFFECTS AT SUBAURORAL LATITUDES - A CASE-STUDY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TOTAL ELECTRON-CONTENT; ATMOSPHERIC GRAVITY-WAVES; F-REGION; MAGNETIC STORM; NEUTRAL COMPOSITION; THERMOSPHERIC COMPOSITION; GEOMAGNETIC STORM; DYNAMICS EXPLORER; MARCH 22; SUDDEN COMMENCEMENT AB An attempt is made to classify ionospheric storm effects at subauroral latitudes according to their presumed origin. The storm of December 7/8, 1982, serves as an example. It is investigated using ionosonde, electron content, and DE 2 satellite data. The following effects are distinguished: (1) positive storm effects caused by traveling atmospheric disturbances, (2) positive storm effects caused by changes in the large-scale thermospheric wind circulation, (3) positive storm effects caused by the expansion of the polar ionization enhancement, (4) negative storm effects caused by perturbations of the neutral gas composition, and (5) negative storm effects caused by the equatorward displacement of the trough region. C1 NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHER LAB, GREENBELT, MD 20771 USA. UNIV MICHIGAN, SPACE PHYS RES LAB, ANN ARBOR, MI 48109 USA. USAF, GEOPHYS LAB, BEDFORD, MA 01731 USA. RP UNIV BONN, INST ASTROPHYS & EXTRATERR FORSCH, AUF HUGEL 71, W-5300 BONN, GERMANY. RI Killeen, Timothy/F-2215-2013 NR 119 TC 96 Z9 100 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1275 EP 1288 DI 10.1029/90JA02326 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600019 ER PT J AU MORGAN, TH SHEMANSKY, DE AF MORGAN, TH SHEMANSKY, DE TI LIMITS TO THE LUNAR ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EARTHS UPPER-ATMOSPHERE; INNER SOLAR-SYSTEM; SMALL COMETS; POLAR-REGIONS; INFLUX; SODIUM; ACCRETION; SURFACES; IMPACT; MOON AB The presence of sodium and potassium on the Moon implies that other more abundant species should be present. Volatile molecules like H2O are significantly more abundant than sodium in any of the proposed external atmospheric sources. Source mechanisms which derive atoms from the surface should favor abundant elements in the regolith. It is therefore puzzling that the Apollo ultraviolet spectrometer experiment set limits on the density of oxygen of N(o) < 5 x 10(2) cm-3, and that the Apollo Lunar Atmospheric Composition Experiment data imply N(o) < 50 cm-3 above the subsolar point. These limits are surprisingly small relative to the measured value for sodium. A simple consideration of sources and sinks predicts significantly greater densities of oxygen. It is possible but doubtful that the Apollo measurements occurred during an epoch in which source rates were small. A preferential loss process for oxygen on the darkside of the Moon is considered in which ionization by electron capture in surface collisions leads to escape through acceleration in the local electric field. Cold trapping in permanently shadowed regions as a net sink is considered and discounted, but the episodic nature of cometary insertion may allow formation of ice layers which act as a stabilized source of OH. On the basis of an assumed meteoroid impact source we predict a possible emission brightness of approximately 50 R in the OH(A - X)(0,0) band above the lunar bright limb. A very uncertain small comet source of H2O could raise this value by more than two orders of magnitude. C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP MORGAN, TH (reprint author), NASA,600 INDEPENDENCE AVE SW,WASHINGTON,DC 20546, USA. RI Morgan, Thomas/I-5943-2013 NR 69 TC 110 Z9 110 U1 0 U2 9 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 1991 VL 96 IS A2 BP 1351 EP 1367 DI 10.1029/90JA02127 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600025 ER PT J AU DESCH, MD FARRELL, WM KAISER, ML AF DESCH, MD FARRELL, WM KAISER, ML TI AN ANOMALOUS COMPONENT OF NEPTUNE RADIO-EMISSION - IMPLICATIONS FOR THE AURORAL-ZONE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ASTRONOMY; URANUS AB The Voyager planetary radio astronomy experiment detected a bursty, narrow-band radio emission originating in Neptune's magnetosphere. The time of occurrence of nearly all of the episodes of this bursty radio emission can be explained on the basis of a radio source located just above and to the east of the south magnetic offset tilted dipole (OTD) tip (Farrell et al., 1990). However, several episodes of bursty emission do not occur at the usual frequency and planetary rotation phase for emissions of this type. We show that the occurrences of these rarely seen anomalous episodes are shifted systematically in planetary longitude so as to be consistent with a source of emission to the southwest of the southern magnetic OTD pole. Owing to the proximity of these sources to the magnetic polar region we associate them with an active auroral region. Therefore, at least from the standpoint of the radio emission, the picture that emerges is of an auroral zone with two emission hot spots approximately diametrically east and west of the south magnetic pole. The possibility of a complete radio-active auroral oval is discussed. RP DESCH, MD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 10 TC 10 Z9 10 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 1991 VL 96 IS A2 BP 1401 EP 1408 DI 10.1029/90JA02325 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600028 ER PT J AU CHANDLER, MO WAITE, JH MOORE, TE AF CHANDLER, MO WAITE, JH MOORE, TE TI OBSERVATIONS OF POLAR ION OUTFLOWS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID THERMAL PROTON FLOWS; TEMPERATURE ANISOTROPY; LATITUDE IONOSPHERE; TOPSIDE IONOSPHERE; DENSITY STRUCTURE; MAGNETIC-FIELD; DE-1 ALTITUDES; ESCAPE FLUXES; WIND; MODEL AB The characteristics of the polar ion outflows as observed in the topside polar ionosphere by the Dynamics Explorer Retarding Ion Mass Spectrometer are reported in this study. The study is restricted to altitudes between 1000 and 4000 km in order to focus on the phenomenon of the "classical polar wind." Except insofar as they convect into the polar cap at these altitudes, auroral and cusp/cleft outflows are specifically excluded from this study. Using a method based on the "relative wind" of ions as seen from the moving spacecraft, averages and variances of the magnetic field-aligned ion flux and velocity, and the species densities, are derived and binned for examination of their altitudinal, seasonal, and magnetic activity dependencies. The data set used encompasses the period from autumn 1981 through 1983, the altitude range from 1000 to 4000 km, and invariant latitudes greater than 70-degrees. Observations of H+, HE+ and O+ with energies down to spacecraft potential are reported. It is found that the polar outflows are not well correlated with common indicators of solar geomagnetic activity. The average parameters of the outflows exhibit a winter enhancement of He+ flux, a winter decrease in H+ flux, and a summer enhancement of the asymptotic outflow speeds of all species. The solar F10.7 (and hence EUV) flux is correlated with the acceleration profile of the flows, with slower flow velocities at 2500 km altitude for active solar conditions. Evidence is found that the H+ flows are, at times, subsonic in the altitude range studied, in contrast to cold polar wind models. C1 SW RES INST,DEPT SPACE SCI,SAN ANTONIO,TX 78284. RP CHANDLER, MO (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 47 TC 94 Z9 94 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 1991 VL 96 IS A2 BP 1421 EP 1428 DI 10.1029/90JA02180 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600030 ER PT J AU LUDLOW, GR HUGHES, WJ ENGEBRETSON, MJ SLAVIN, JA SUGIURA, M SINGER, HJ AF LUDLOW, GR HUGHES, WJ ENGEBRETSON, MJ SLAVIN, JA SUGIURA, M SINGER, HJ TI ION-CYCLOTRON WAVES NEAR L = 4.6 - A GROUND-SATELLITE CORRELATION STUDY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SYNCHRONOUS ORBIT; MAGNETOSPHERE; PULSATIONS; IONOSPHERE; MAGSAT; REGION; GEOS-1 AB We present results of the first ground-satellite correlation study of ion cyclotron wave events inside geosynchronous orbit. We found several intervals during which waves at the same frequency were observed simultaneously by the DE 1 Goddard Space Flight Center Fluxgate Magnetometer and by the Air Force Geophysics Laboratory Magnetometer Network. This represents about 33% of the intervals during which waves were seen on the ground and DE 1 was in a favorable location (near the geomagnetic equator around L = 4.6) to observe the wave generation region. Three of seven simultaneous events showed a positive correlation when a detailed correlation analysis was performed. The broadband nature of the other events prevented any detailed correlation analysis. Peaks in the cross-correlation function occurred at delays of 30-100 s and are interpreted as the group delay time of signals from space to the ground station. The small number of events seen in space during conjunction intervals results from the satellite's path missing the source region. When sources are missed by the satellite path, they either exist at higher or lower L shells and are ducted in the ionosphere to the network (l = 3) or they exist at the satellite L shell but are missed due to their small spatial extent in local time. C1 AUGSBURG COLL,DEPT PHYS,MINNEAPOLIS,MN. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. TOKAI UNIV,INST RES & DEV,TOKYO,JAPAN. SPACE PLASMAS & FIELDS BRANCH,GEOPHYS LAB,BEDFORD,MA. RP LUDLOW, GR (reprint author), BOSTON UNIV,CTR SPACE PHYS,725 COMMONWEALTH AVE,BOSTON,MA 02215, USA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 25 TC 14 Z9 14 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1451 EP 1466 DI 10.1029/90JA02005 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600033 ER PT J AU FAIRFIELD, DH AF FAIRFIELD, DH TI AN EVALUATION OF THE TSYGANENKO MAGNETIC-FIELD MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EQUATORIAL MAGNETOTAIL; GEOMAGNETIC-FIELD; NEUTRAL SHEET; MAGNETOSPHERE; TAIL AB A data set of more than 22,000 vector averages of the magnetosphere magnetic field over 0.5 R(E) regions is used to evaluate Tsyganenko's 1982 and 1987 magnetospheric magnetic field models. The magnetic field predicted by the model in various regions is compared to observations to find systematic discrepancies which future models might address. While agreement is generally good, discrepancies are noted which include: (1) a lack of adequate field line stretching in the tail and ring current regions; (2) an inability to predict weak enough fields in the polar cusps; and (3) a deficiency of Kp as a predictor of the field configuration. RP FAIRFIELD, DH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 15 TC 31 Z9 31 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 1991 VL 96 IS A2 BP 1481 EP 1494 DI 10.1029/90JA02095 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600035 ER PT J AU FOK, MC KOZYRA, JU BRACE, LH AF FOK, MC KOZYRA, JU BRACE, LH TI SOLAR-CYCLE VARIATION IN THE SUBAURORAL ELECTRON-TEMPERATURE ENHANCEMENT - COMPARISON OF AE-C AND DE 2 SATELLITE-OBSERVATIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID AURORAL RED ARCS AB The elevation of the subauroral electron temperature is one of the phenomena showing the energy transfer from the magnetosphere and the response of the ionosphere. The present study addresses solar cycle variations in the subauroral Te peak by comparing observations of the subauroral peak by the Atmosphere Explorer C (AE-C) satellite near solar minimum (1974 and 1977) with similar observations by the Dynamics Explorer 2 (DE 2) satellite near solar maximum (1981-1982). Electron temperature peaks with magnitudes sufficient to produce observable stable auroral red (SAR) arc emissions occurred more frequently during solar maximum than in solar minimum by the variation in the magnitudes and positions of these peaks with magnetic activity did not change significantly with solar cycle. These results will be discussed in terms of the solar cycle changes in the ionosphere and the magnetospheric energy source. C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY ATMOSPHER BRANCH,GREENBELT,MD 20771. RP FOK, MC (reprint author), UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES LAB,ANN ARBOR,MI 48109, USA. RI Fok, Mei-Ching/D-1626-2012 NR 21 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1861 EP 1866 DI 10.1029/90JA02377 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600069 ER PT J AU TSURUTANI, BT GONZALEZ, WD AF TSURUTANI, BT GONZALEZ, WD TI DO INTERPLANETARY ALFVEN WAVES CAUSE AURORAL ACTIVITY - COMMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Letter ID SOLAR-WIND C1 INST PESQUISAS ESPACIAIS,SAO JOSE CAMPOS,SP,BRAZIL. RP TSURUTANI, BT (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 11 TC 0 Z9 0 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 1991 VL 96 IS A2 BP 1877 EP 1878 DI 10.1029/90JA02448 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600073 ER PT J AU ROBERTS, DA GOLDSTEIN, ML AF ROBERTS, DA GOLDSTEIN, ML TI DO INTERPLANETARY ALFVEN WAVES CAUSE AURORAL ACTIVITY - REPLY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Letter RP ROBERTS, DA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI Roberts, Dana/D-4625-2012; Goldstein, Melvyn/B-1724-2008 NR 4 TC 0 Z9 0 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 1991 VL 96 IS A2 BP 1879 EP 1880 DI 10.1029/90JA02447 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600074 ER PT J AU CAO, Y FAGHRI, A JUHASZ, A AF CAO, Y FAGHRI, A JUHASZ, A TI A PCM FORCED-CONVECTION CONJUGATE TRANSIENT ANALYSIS OF ENERGY-STORAGE SYSTEMS WITH ANNULAR AND COUNTERCURRENT FLOWS SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE CONJUGATE HEAT TRANSFER; PHASE-CHANGE PHENOMENA; THERMAL ENERGY STORAGE ID NUMERICAL-ANALYSIS AB Latent heat energy storage systems with both annular and countercurrent flows are modeled numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. It is found that the energy storage system with the countercurrent flow is an efficient way to absorb heat energy in a short period for pulsed power load space applications. C1 WRIGHT STATE UNIV,DEPT MECH & MAT ENGN,DAYTON,OH 45435. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 9 TC 5 Z9 6 U1 0 U2 0 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 1991 VL 113 IS 1 BP 37 EP 42 DI 10.1115/1.2910548 PG 6 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HP758 UT WOS:A1991HP75800005 ER PT J AU SIEGEL, R AF SIEGEL, R TI ANALYTICAL SOLUTION FOR BOUNDARY HEAT FLUXES FROM A RADIATING RECTANGULAR MEDIUM SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Note DE FURNACES AND COMBUSTORS; RADIATION ID TRANSPORT-EQUATION C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 6 TC 9 Z9 9 U1 0 U2 0 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 1991 VL 113 IS 1 BP 258 EP 261 DI 10.1115/1.2910539 PG 4 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HP758 UT WOS:A1991HP75800039 ER PT J AU MILMAN, M SCHUMITZKY, A AF MILMAN, M SCHUMITZKY, A TI FACTORIZATION AND QUADRATIC COST PROBLEMS IN HILBERT-SPACES SO JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS LA English DT Article ID RICCATI INTEGRAL-EQUATIONS; EVOLUTION-EQUATIONS; FEEDBACK; SYSTEMS; DELAYS; STATE C1 UNIV SO CALIF,DEPT MATH,LOS ANGELES,CA 90089. RP MILMAN, M (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 24 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-247X J9 J MATH ANAL APPL JI J. Math. Anal. Appl. PD FEB PY 1991 VL 155 IS 1 BP 111 EP 130 DI 10.1016/0022-247X(91)90030-4 PG 20 WC Mathematics, Applied; Mathematics SC Mathematics GA EX308 UT WOS:A1991EX30800008 ER PT J AU TAROKH, M SERAJI, H AF TAROKH, M SERAJI, H TI A MULTIVARIABLE CONTROL SCHEME FOR ROBOT MANIPULATORS SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article ID MODELS AB The article puts forward a simple scheme for multivariable control of robot manipulators to achieve trajectory tracking. The scheme is composed of an inner loop stabilizing controller and an outer loop tracking controller. The inner loop utilizes a multivariable PD controller to stabilize the robot by placing the poles of the linearized robot model at some desired locations. The outer loop employs a multivariable PID controller to achieve input-output decoupling and trajectory tracking. The gains of the PD and PID controllers are related directly to the linearized robot model by simple closed-form expressions. The controller gains are updated on-line to cope with variations in the robot model during gross motion and for payload change. Alternatively, the use of high gain controllers for gross motion and payload change is discussed. Computer simulation results are given for illustration. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP TAROKH, M (reprint author), SAN DIEGO STATE UNIV,DEPT MATH SCI,SAN DIEGO,CA 92182, USA. NR 14 TC 2 Z9 2 U1 0 U2 0 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 1991 VL 8 IS 1 BP 1 EP 19 DI 10.1002/rob.4620080102 PG 19 WC Robotics SC Robotics GA EV678 UT WOS:A1991EV67800001 ER PT J AU SHIPLEY, C CARTERETTE, EC BUCHWALD, JS AF SHIPLEY, C CARTERETTE, EC BUCHWALD, JS TI THE EFFECTS OF ARTICULATION ON THE ACOUSTICAL STRUCTURE OF FELINE VOCALIZATIONS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID NEWBORN; CAT AB Feline isolation calls were analyzed, and a model was developed to relate the acoustical features of these calls to the physical processes used in their production. Fifty isolation calls were recorded from each of five cats for a total sample of 250 vocalizations. By combinations of Fourier transform, autocorrelation, and linear prediction methods, the fundamental frequency (glottal-pulse period) F0, the energy of F0, the frequency having maximum energy F(max) (not always F0), and the energy at this frequency were computed. Mean F0 ranged from 400-600 Hz for individual cats. For some cats F0 was consistent within calls, but for other cats sudden shifts in F0 occurred within calls. Here, F(max) was almost always a harmonic of F0 and generally ranged from 1-2 kHz. For individual cats, the energy ratio E = (energy of F(max)/energy of F0) varied from 1 to 60 and the grand average E over the time course of the call varied from about 12 to 38. The mean rms call intensity was an inverted-U function of time. Measured jaw opening was strongly correlated with acoustical features of call. A Bessel-horn model with time-varying flare gave a good account of acoustical parameters such as F(max). The presence of formantlike resonances in cat vocalizations and the important role of jaw movements (vocal gestures) in the production of these calls suggest that cats may provide a useful model for some aspects of human vocal behavior. C1 UNIV CALIF LOS ANGELES,DEPT PHYSIOL & PSYCHOL,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,BRAIN RES INST,LOS ANGELES,CA 90024. RP SHIPLEY, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE BLVD,PASADENA,CA 91109, USA. FU NICHD NIH HHS [HD-04612, HD-05958] NR 14 TC 27 Z9 27 U1 2 U2 12 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 1991 VL 89 IS 2 BP 902 EP 909 DI 10.1121/1.1894652 PG 8 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA EX020 UT WOS:A1991EX02000045 PM 2016439 ER PT J AU MISRA, AK AF MISRA, AK TI THERMOCHEMICAL ANALYSIS OF THE SILICON-CARBIDE ALUMINA REACTION WITH REFERENCE TO LIQUID-PHASE SINTERING OF SILICON-CARBIDE SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article DE SILICON CARBIDE; ALUMINA; PHASES; MODELS; THERMODYNAMICS ID BEHAVIOR; ADDITIONS AB The stabilities of different phases in the Si-Al-C-O system are calculated from thermodynamic consideration with the objective of identifying the liquid phases formed during sintering of SiC in the presence of Al2O3. It is shown that a liquid phase can form at the sintering temperatures by the reaction of SiC with Al2O3. Depending on the carbon activity, the liquid can be either of the following: Al2O3 + Al4C3, SiC + Al4C3, or molten aluminum. The stability of the aluminosilicate melts that can form by the reaction of Al2O3 with the surface silica layer on SiC powders is also evaluated. Several factors that influence liquid-phase sintering, such as the solubility of SiC in the melts and the generation of gases during sintering, are discussed. The results of the thermodynamic analysis are compared with the observed sintering behavior for SiC. RP MISRA, AK (reprint author), NASA,LEWIS RES CTR,SVERDRUP TECHNOL INC,CLEVELAND,OH 44135, USA. NR 20 TC 59 Z9 62 U1 1 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 1991 VL 74 IS 2 BP 345 EP 351 DI 10.1111/j.1151-2916.1991.tb06885.x PG 7 WC Materials Science, Ceramics SC Materials Science GA EX751 UT WOS:A1991EX75100014 ER PT J AU GREEN, RN SMITH, GL AF GREEN, RN SMITH, GL TI SHORTWAVE SHAPE FACTOR INVERSION OF EARTH RADIATION BUDGET OBSERVATIONS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SATELLITE AB The shape factor technique is routinely used to invert wide-angle radiometric measurements at satellite altitude to flux at the top of the atmosphere. The derivation of a shortwave shape factor requires assumptions on both the viewed radiation field and the angular distribution of the radiance. This paper describes the effect on the shape factor of assuming a constant flux field, a constant albedo field, and a variable albedo field. In addition, three assumptions on the angular distributions are investigated: Lambertian, an analytic model, and the Earth Radiation Budget Experiment (ERBE) bidirectional models. The accuracies and resolutions of the shape factor flux estimates arising from these assumptions are determined by simulating the shape factor inversion technique with ERBE scanner data. First, the scanner data are summed at satellite altitude to simulate the wide-angle radiometric measurements. Radiant flux at the top of the atmosphere is then estimated from these simulated wide-angle measurements with the various shape factors and compared to the original scanner flux field. The resulting biases and variances are given for both the ERBE medium-field-of-view and wide-field-of-view radiometers. RP GREEN, RN (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23665, USA. NR 16 TC 4 Z9 4 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 FEB 1 PY 1991 VL 48 IS 3 BP 390 EP 402 DI 10.1175/1520-0469(1991)048<0390:SSFIOE>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FA765 UT WOS:A1991FA76500002 ER PT J AU MANSON, AH MEEK, CE FLEMING, E CHANDRA, S VINCENT, RA PHILLIPS, A AVERY, SK FRASER, GJ SMITH, MJ FELLOUS, JL MASSEBEUF, M AF MANSON, AH MEEK, CE FLEMING, E CHANDRA, S VINCENT, RA PHILLIPS, A AVERY, SK FRASER, GJ SMITH, MJ FELLOUS, JL MASSEBEUF, M TI COMPARISONS BETWEEN SATELLITE-DERIVED GRADIENT WINDS AND RADAR-DERIVED WINDS FROM THE CIRA-86 SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID WAVE MOMENTUM FLUXES; 107-DEGREES-W MF RADAR; GRAVITY-WAVE; SASKATOON 52-DEGREES-N; MIDDLE ATMOSPHERE; UPPER MESOSPHERE; POKER-FLAT; SUMMER; WINTER; ALASKA AB Satellite-radiance data (Nimbus 5, 6; less-than-or-equal-to 80 km) and the MSIS-83 model have been used to prepare global zonal-mean gradient winds (30-120 km) for the new CIRA-1986. Here these are supplemented by planetary-wave morphology from the same Nimbus data to provide local gradient winds-the zonal wind and the eddy portion of the meridional wind are calculated by this method. These data are then compared with radar-derived wind contours (approximately 60-110 km), extending the comparisons done earlier (Manson et al.) for heights below 80 km. Overall the agreement for the zonal winds is good, especially below 80 km; differences are shown so the user can evaluate each product. The comparison of meridional winds is particularly valuable and unique as it reveals considerable ageostrophy, particularly in summer months near the heights of the zonal wind's reversal from west- to eastward flow. Coriolis torques due to this meridional flow are available from Saskatoon (52-degrees), Poker Flat (65-degrees), and Tromso (70-degrees) in the Northern Hemisphere, and Adelaide (35-degrees), Christchurch (44-degrees), and Mawson (68-degrees) in the Southern Hemisphere. Values of 60-100 m s-1 day-1 are generally consistent with estimates of the balancing gravity wave momentum deposition made by direct methods at the same locations. C1 APPL RES CORP,LANDOVER,MD. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV ADELAIDE,DEPT PHYS & MATH PHYS,ADELAIDE,SA 5001,AUSTRALIA. UNIV COLORADO,DEPT ELECT & COMP ENGN,BOULDER,CO 80309. UNIV CANTERBURY,DEPT PHYS,CHRISTCHURCH 1,NEW ZEALAND. DSIR,PHYS & ENGN LAB,LOWER HUTT,NEW ZEALAND. CTR NATL ETUD SCI,PARIS,FRANCE. CNRS,CTR RECH PHYS ETUD,F-75005 PARIS,FRANCE. RP MANSON, AH (reprint author), UNIV SASKATCHEWAN,INST SPACE & ATMOSPHER STUDIES,SASKATOON S7N 0W0,SASKATCHEWAN,CANADA. NR 29 TC 61 Z9 62 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD FEB 1 PY 1991 VL 48 IS 3 BP 411 EP 428 DI 10.1175/1520-0469(1991)048<0411:CBSDGW>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FA765 UT WOS:A1991FA76500004 ER PT J AU WHITTENBERGER, JD KUMAR, KS MANNAN, SK AF WHITTENBERGER, JD KUMAR, KS MANNAN, SK TI 1200-K AND 1300-K SLOW PLASTIC COMPRESSION PROPERTIES OF NI-50AL COMPOSITES SO MATERIALS AT HIGH TEMPERATURES LA English DT Article DE INTERMETALLIC COMPOSITES; STRESS-STRAIN BEHAVIOR; CREEP; NIAL; SLOW PLASTIC COMPRESSION AB XD(TM) synthesis, powder blending and hot pressing techniques have been utilized to produce NiAl composites containing 4, 7.5, 15 and 25 vol% alumina whiskers and hybrid composite materials with 15 vol% Al2O3 + 10 or 20 vol%, nominally 1-mu-m TiB2 particles. The resistance to slow plastic flow was determined at 1200 and 1300 K via compression testing in air under constant velocity conditions. The stress-strain behaviour of the intermetallic composites depended on the fraction of second phases where the 4 and 7.5% Al2O3 materials flowed at a nominally constant stress after about 2% deformation, while all the other composites exhibited diffuse yielding followed by strain softening. The flow stress-strain rate properties increased with volume fraction of Al2O3 whiskers except for the 4 and 7.5% materials, which had similar strengths. The hybrid composite NiAl + 15Al2O3 + 10TiB2 was substantially stronger than the materials simply containing alumina. Deformation in these composites can be described by the Kelly and Street model of creep in perfectly bonded, rigid, discontinuous fibre materials. RP WHITTENBERGER, JD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0960-3409 J9 MATER HIGH TEMP JI Mater. High Temp. PD FEB PY 1991 VL 9 IS 1 BP 3 EP 12 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA FG818 UT WOS:A1991FG81800001 ER PT J AU VIJAYAKUMAR, M TEWARI, SN LEE, JE CURRERI, PA AF VIJAYAKUMAR, M TEWARI, SN LEE, JE CURRERI, PA TI DENDRITE SPACINGS IN DIRECTIONALLY SOLIDIFIED SUPERALLOY PWA-1480 SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID GROWTH; MORPHOLOGY AB Primary dendrite spacings and side-branch coarsening kinetics were examined in specimens of the single-crystal multicomponent commercial superalloy PWA-1480, which were directionally solidified in a positive thermal gradient. The experimentally observed dependence of primary dendrite spacings and side-branch coarsening kinetics on growth rate and thermal gradient were in agreement with the behavior predicted by analytical models developed for binary alloys. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP VIJAYAKUMAR, M (reprint author), CLEVELAND STATE UNIV,DEPT CHEM ENGN,CLEVELAND,OH 44115, USA. NR 23 TC 19 Z9 20 U1 2 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB PY 1991 VL 132 BP 195 EP 201 DI 10.1016/0921-5093(91)90375-W PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100021 ER PT J AU HUANG, J AF HUANG, J TI DUAL-POLARIZED MICROSTRIP ARRAY WITH HIGH ISOLATION AND LOW CROSS-POLARIZATION SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article DE MICROSTRIP ANTENNA; DUAL-POLARIZATION; ISOLATION; CROSS-POL AB A 2 x 2 dual-polarized microstrip array antenna with high isolation between the two input ports and low cross-polarization level has been developed. The technical background for this achievement and antenna performance results are presented. RP HUANG, J (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 17 Z9 18 U1 1 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD FEB PY 1991 VL 4 IS 3 BP 99 EP 103 DI 10.1002/mop.4650040304 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA FC044 UT WOS:A1991FC04400003 ER PT J AU MAY, BD AF MAY, BD TI PULSED RESPONSE OF A TWT SO MICROWAVE JOURNAL LA English DT Article AB The consequence of frequency domain multiple access channelization in a satellite communications system is that the ground- and space-based components often are required to operate in a linear region to prevent the generation of distortion signals. Components of a time division multiple access (TDMA) satellite system, such as a traveling-wave tube (TWT), can operate in the highest output power state because the channelization technique is relatively insensitive to the distortions resulting from saturated operation. A 30 GHz TWT was tested to determine the suitability of such a device in a TDMA system. Testing was focused on the ability of the TWT's output signal to rise up to full power at the leading edge of TDMA bursts, simulated by a pulse train. A peak power meter was used to display and measure the pulsed signal waveform. Measurements on the TWT output pulse rise time indicate that the TWT lengthened the rise time by 10 to 20 ns. Imposing modulator turn on timing that precedes the data burst by the TWT rise time is a logical approach to coordination of the two subsystem specification. RP MAY, BD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU HORIZON HOUSE-MICROWAVE PI NORWOOD PA 685 CANTON ST, NORWOOD, MA 02062 SN 0192-6225 J9 MICROWAVE J JI Microw. J. PD FEB PY 1991 VL 34 IS 2 BP 113 EP & PG 0 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA EX944 UT WOS:A1991EX94400006 ER PT J AU HEYMSFIELD, GM FULTON, R SPINHIRNE, JD AF HEYMSFIELD, GM FULTON, R SPINHIRNE, JD TI AIRCRAFT OVERFLIGHT MEASUREMENTS OF MIDWEST SEVERE STORMS - IMPLICATIONS ON GEOSYNCHRONOUS SATELLITE INTERPRETATIONS SO MONTHLY WEATHER REVIEW LA English DT Article ID 3-DIMENSIONAL NUMERICAL-SIMULATION; OKLAHOMA TORNADIC STORMS; UPPER-LEVEL STRUCTURE; CLOUD-TOP STRUCTURE; DYNAMICS; ATMOSPHERE; MODEL; RADAR AB The instrumented NASA ER-2 aircraft overflew severe convection with infrared (IR) V features for the first time in the Midwest United States during May 1984. Measurements taken by the ER-2 were: visible and IR imagery, high-frequency passive microwave (92, 183 GHz) imagery, nadir lidar backscattered return, and flight altitude information. The 7 May and 13 May 1984 cases are analyzed in detail and the various data sources are combined and compared with GOES imagery. Topics addressed in the paper are 1) relation of thermal couplets and V features in aircraft IR measurements to previous findings from GOES data, 2) examination of the cloud radiative hypothesis for the V feature, and 3) stratospheric perturbations above severe thunderstorms and mesoscale convective systems. The high resolution aircraft IR imagery shows that thermal couplets are considerably more pronounced than in GOES imagery. In one of the cases (7 May 1984) the minimum cloud-top IR temperature was located upshear of the overshooting cloud top in the lidar height field. This was suggested in previous papers to result from cloud top mixing with the stratospheric environment and subsidence. The IR temperatures in the downshear anvils were as much as 5-degrees-C warmer than the ambient air temperatures, implying that the upwelling IR radiance comes from about 0.5-1.0 km below the cloud top. Finally, the in situ ER-2 measurements of temperature and air velocity 3-4 km above the overshooting tops showed very intense temperature and vertical velocity perturbations. These perturbations are suggestive of 1) lee waves generated by the overshooting tops, or 2) a cold dome above the squall line possibly due to tropopause lifting by the storms. C1 GEN SCI CORP,LAUREL,MD. RP HEYMSFIELD, GM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. NR 33 TC 26 Z9 26 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD FEB PY 1991 VL 119 IS 2 BP 436 EP 456 DI 10.1175/1520-0493(1991)119<0436:AOMOMS>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FD131 UT WOS:A1991FD13100010 ER PT J AU SRIVASTAVA, V JARZEMBSKI, MA AF SRIVASTAVA, V JARZEMBSKI, MA TI LASER-INDUCED STIMULATED RAMAN-SCATTERING IN THE FORWARD DIRECTION OF A DROPLET - COMPARISON OF MIE THEORY WITH GEOMETRICAL-OPTICS SO OPTICS LETTERS LA English DT Article ID MICROMETER-SIZED DROPLETS; FIELD; BREAKDOWN AB Comparison of Mie theory calculations of the internal electromagnetic source function for a 120-mu-m-diameter water droplet with geometrical optics suggests that the field enhancement located at the critical ring region encircling the axis in the forward direction of the droplet can support stimulated Raman scattering as found experimentally. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP SRIVASTAVA, V (reprint author), UNIV SPACE RES ASSOC,4950 CORP DR,HUNTSVILLE,AL 35806, USA. NR 15 TC 27 Z9 27 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 1 PY 1991 VL 16 IS 3 BP 126 EP 128 DI 10.1364/OL.16.000126 PG 3 WC Optics SC Optics GA EV197 UT WOS:A1991EV19700004 PM 19773857 ER PT J AU ORMSBY, JP HALL, DD AF ORMSBY, JP HALL, DD TI SPECTRAL PROPERTIES OF FOG OVER THE MALASPINA GLACIER, ALASKA, IN COMPARISON TO SNOW, ICE, AND CLOUDS SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID THEMATIC MAPPER AB Analysis of Landsat 5 Thematic Mapper (TM) data of the Malaspina Glacier in southeastern Alaska has shown that fog overlying the glacier ice has reflectance characteristics similar to the ice below and that the spectral reflectance of fog can be different from other types of clouds. Fog is more reflective in the visible and near-infrared wavelengths compared to snow, ice, and cumulus clouds. The differentiation between clouds, fog, and the ice below can be enhanced by combining TM bands in the visible part of the spectrum. RP ORMSBY, JP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,HYDROL SCI BRANCH,GREENBELT,MD 20771, USA. NR 27 TC 1 Z9 1 U1 0 U2 3 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD FEB PY 1991 VL 57 IS 2 BP 179 EP 185 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA EW206 UT WOS:A1991EW20600006 ER PT J AU HU, CY BHATIA, AK AF HU, CY BHATIA, AK TI RESONANCES IN MUONIC SYSTEMS SO PHYSICAL REVIEW A LA English DT Article ID DT-MU; VARIATIONAL CALCULATIONS; MOLECULES; STATES AB A number of resonances, shape as well as Feshbach type, have been observed in atomic systems. It is expected that similar types of resonances exist in muonic systems. Froelich and Szalewicz [Phys. Lett. A 129, 321 (1988)] carried out a calculation for td-mu and obtained two resonances, for J = 0 and 1, just above the d-mu-threshold. Our calculation, carried out with large basis sets and different sets of nonlinear parameters, using the complex-rotation method, shows the existence of Feshbach-type resonances below the n = 2 threshold of t-mu and d-mu. Positions of these resonances are in good agreement with the results of Hara and Ishihara [Phys. Rev. A 40, 4232 (1989)]. The widths of these resonances are calculated. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP HU, CY (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024, USA. NR 15 TC 15 Z9 15 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 1 PY 1991 VL 43 IS 3 BP 1229 EP 1232 DI 10.1103/PhysRevA.43.1229 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800012 ER PT J AU HU, S HOJAJI, H BARKATT, A BOROOMAND, M THORPE, AN ALTERESCU, S AF HU, S HOJAJI, H BARKATT, A BOROOMAND, M THORPE, AN ALTERESCU, S TI ANISOTROPIC ELECTROMAGNETIC FEATURES OF A GRAIN-ALIGNED YBA2CU3OX BULK SUPERCONDUCTOR SO PHYSICAL REVIEW B LA English DT Article ID BA-CU-O; AC MAGNETIC-SUSCEPTIBILITY; HIGH-TC SUPERCONDUCTORS; CRITICAL STATE MODEL; CRITICAL CURRENTS; CRYSTAL; YBACUO AB The anisotropic electromagnetic features of a grain-aligned YBa2Cu3O(x) bulk sample derived from a process of long-time partial melt growth were investigated by the measurements of dc magnetization (at 77 K) and ac susceptibility as a function of temperature, with the fields applied parallel and perpendicular to the c axis, respectively. The extended Bean model was further studied and applied to explain the experimental results. Upon comparison of the grain-aligned sample with pure single-crystal materials, it is concluded that, because of the existence of more effective pinning sites in the grain-aligned sample, not only its critical current density perpendicular to the c axis is improved, but the one parallel to the c axis is improved even more significantly. The anisotropy in the critical current densities in the grain-aligned sample at 77 K is at least 1 to 2 orders of magnitude smaller than in the pure single crystal. The measurement of anisotropy of ac susceptibility as a function of temperature, especially its imaginary part, shows that there are still some residues of interlayer weak links in the grain-aligned samples, but they are quite different from and far less serious than the weak links in the sintered samples. C1 HOWARD UNIV,WASHINGTON,DC 20059. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770. RP HU, S (reprint author), CATHOLIC UNIV AMER,WASHINGTON,DC 20064, USA. NR 25 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2878 EP 2884 DI 10.1103/PhysRevB.43.2878 PN A PG 7 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300052 ER PT J AU AUSTERN, N AF AUSTERN, N TI COULOMB-DOMINATED LOW-ENERGY DEUTERON STRIPPING SO PHYSICAL REVIEW C LA English DT Article AB Analysis of a three-body model shows that Coulomb polarization of the deuteron has very little influence on the branching ratio A(d,p)/A(d,n) for transfer reactions on target nucleus A at very low deuteron energies (the Oppenheimer-Phillips effect). We see that polarization effects in transfer reactions are not related to the long range of the Coulomb field, but are caused by the more intense fields near the target nucleus. However, even in that region the induced dipole moment is limited by the deutron binding, and it is small for low Z targets. We see in addition that the transfer amplitudes tend to be insensitive to any polarization admixtures in the entrance channel. On the other hand, the branching ratio can be affected by the Coulomb barrier for the bound final-state wave function of the proton, especially for very weakly bound final states. Brief remarks about the relation of stripping theory to special properties of the d+d system are included. RP AUSTERN, N (reprint author), NASA,LEWIS RES CTR,DEPT PHYS & ASTRON,CLEVELAND,OH 44135, USA. NR 14 TC 3 Z9 3 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 771 EP 774 DI 10.1103/PhysRevC.43.771 PG 4 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100038 ER PT J AU ALLEN, L BUCHSBAUM, SJ GIBBONS, JH HECKER, SS KNAPP, EA YONAS, G LUBKIN, GB GOODWIN, I LEVI, BG AF ALLEN, L BUCHSBAUM, SJ GIBBONS, JH HECKER, SS KNAPP, EA YONAS, G LUBKIN, GB GOODWIN, I LEVI, BG TI ROUND-TABLE - NEW CHALLENGES FOR THE NATIONAL LABS SO PHYSICS TODAY LA English DT Discussion AB America's government laboratories are a reservoir of scientific and technological capabilities. They contribute to national defense, scientific discoveries, space exploration, better agriculture and improved health care. Over the past decade, Congress has directed the labs to pass along their research ideas and technological knowhow to commercial companies in an effort to enhance the country's competitiveness in global markets. In an attempt to understand how the national labs can best achieve their new mission while retaining their old strengths, PHYSICS TODAY editors brought together six prominent members of the nation's R&D enterprise to discuss the issues. C1 AT&T BELL LABS,TECHNOL SYST,MURRAY HILL,NJ 07974. US CONGRESS,OFF TECHNOL ASSESSMENT,WASHINGTON,DC. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. NATL SCI FDN,WASHINGTON,DC 20550. SANDIA NATL LABS,LAB DEV,ALBUQUERQUE,NM 87185. RP ALLEN, L (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD FEB PY 1991 VL 44 IS 2 BP 24 EP 35 DI 10.1063/1.881279 PG 12 WC Physics, Multidisciplinary SC Physics GA EX276 UT WOS:A1991EX27600009 ER PT J AU YOUNG, AT GENET, RM BOYD, LJ BORUCKI, WJ LOCKWOOD, GW HENRY, GW HALL, DS SMITH, DP BALIUNAS, SL DONAHUE, R EPAND, DH AF YOUNG, AT GENET, RM BOYD, LJ BORUCKI, WJ LOCKWOOD, GW HENRY, GW HALL, DS SMITH, DP BALIUNAS, SL DONAHUE, R EPAND, DH TI PRECISE AUTOMATIC DIFFERENTIAL STELLAR PHOTOMETRY SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE PHOTOMETRY; EXTINCTION; AUTOMATION ID CHROMOSPHERICALLY ACTIVE STARS; RESPONSE SELF-CALIBRATION; ATMOSPHERIC EXTINCTION; ECLIPSING BINARIES; DIODES; ACCURACY; VARIABILITY; REDUCTION; SYSTEMS; LAYER AB We review the factors limiting the precision of differential stellar photometry. Errors due to variable atmospheric extinction can be reduced to below 0.001 mag at good sites by utilizing the speed of robotic telescopes. Existing photometric systems produce aliasing errors, which are several millimagnitudes in general but may be reduced to about a millimagnitude in special circumstances. Conventional differential photometry neglects several other important effects, which we discuss in detail. If all of these are properly handled, it appears possible to do differential photometry of variable stars with an overall precision of 0.001 mag with ground-based robotic telescopes. C1 FAIRBORN OBSERV,MESA,AZ 85204. NASA,AMES RES CTR,THEORET STUDIES BRANCH,MOFFETT FIELD,CA 94087. LOWELL OBSERV,FLAGSTAFF,AZ 86001. TENNESSEE STATE UNIV,CTR EXCELLENCE INFORMAT SYST,NASHVILLE,TN 37203. VANDERBILT UNIV,DYER OBSERV,NASHVILLE,TN 37235. UNIV NEVADA,DEPT PHYS,LAS VEGAS,NV 89154. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. RP YOUNG, AT (reprint author), SAN DIEGO STATE UNIV,DEPT ASTRON,SAN DIEGO,CA 92182, USA. NR 106 TC 78 Z9 79 U1 1 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD FEB PY 1991 VL 103 IS 660 BP 221 EP 242 DI 10.1086/132811 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FA383 UT WOS:A1991FA38300009 ER PT J AU WILLIAMS, DL AF WILLIAMS, DL TI A COMPARISON OF SPECTRAL REFLECTANCE PROPERTIES AT THE NEEDLE, BRANCH, AND CANOPY LEVEL FOR SELECTED CONIFER SPECIES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SITCHENSIS BONG CARR; SATELLITE DATA; PHOTOSYNTHESIS; VEGETATION; SPRUCE; RADIATION; PINE AB The optical-reflective radiative transfer characteristics of three conifer species [Norway spruce (Picea abies), red pine (Pinus resinosa), and white pine (Pinus strobus)] and one broadleaf, deciduous species [sugar maple (Acer saccharum)] were measured and compared at the leaf, twig, branch and canopy level. The magnitude of reflectance throughout the visible and near infrared wavelength region was found to decrease dramatically for the conifer species as scene complexity increased from the needle, to the branch, to the canopy level. Comparison of the conifer data with equivalent data obtained for sugar maple served to validate quantitatively that conifer canopies, in general, are more absorptive than their deciduous counterparts, particularly in the near infrared region. These data emphasize the role of canopy constituents, such as needles, twigs, branches, bark, and understory material, in altering the reflectance characteristics of the overall "scene," and may be valuable in developing improved radiative transfer models for forest canopies. RP WILLIAMS, DL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERRESTRIAL PHYS LAB,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. NR 36 TC 83 Z9 84 U1 0 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB-MAR PY 1991 VL 35 IS 2-3 BP 79 EP 93 DI 10.1016/0034-4257(91)90002-N PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FR683 UT WOS:A1991FR68300002 ER PT J AU HALL, FG SELLERS, PJ STREBEL, DE KANEMASU, ET KELLY, RD BLAD, BL MARKHAM, BJ WANG, JR HUEMMRICH, F AF HALL, FG SELLERS, PJ STREBEL, DE KANEMASU, ET KELLY, RD BLAD, BL MARKHAM, BJ WANG, JR HUEMMRICH, F TI SATELLITE REMOTE-SENSING OF SURFACE-ENERGY AND MASS BALANCE - RESULTS FROM FIFE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB In FIFE a diverse, interdisciplinary group of scientists are cooperating to understand how the earth's land-surface vegetation and atmospheric boundary layer interact to affect weather and climate. The focus of this research is the interception of solar and long-wave radiation by a vegetated surface, and the subsequent thermodynamic and biological control of sensible and latent heat release. In addition, the science teams are investigating the use of satellite remote sensing to monitor the components of the surface energy balance at point, regional and global scales. Field experiments were conducted in the summer of 1987 and again in the summer of 1989. Analyses of the 1987 data are reasonably mature, whereas the 1989 data analyses are in the early stages. In this paper we summarize the results of the analyses to date. The analyses have shown that the hypotheses linking energy balance components to surface biology and remote sensing are reasonable at a point level, and that satellite remote sensing can potentially provide useful estimates of the surface energy budget. GOES data have been used to estimate solar insolation at the earth's surface to an accuracy of about 21.6 W m-2 and about 8.2 W m-2 for photosynthetically active radiation. The ratio of near-infrared to red reflectance has also shown to be linearly related to measured CO2 flux. Radiometric temperatures estimated from remote sensing are highly correlated to the canopy aerodynamic temperatures; however, the remote sensing estimation of H to useful accuracies (+/- 100 W m-2) appears to be a more difficult problem than the accurate estimation of LE. The investigation of atmospheric scattering and absorption effects on satellite remote sensing of surface radiance shows that the magnitude of atmospheric opacity variations within the FIFE site and with season can have a large effect on satellite measured values of surface radiances. However, comparisons of atmospherically corrected TM radiances with surface measured radiances agreed to within about 2% in the visible and near-infrared wavelengths and to 6% in the mid-infrared. Looking at the frequency of cloud-free (< 10%) acquisitions actually achieved during FIFE shows that for land-surface climatology, multiple polar orbiters may be required to achieve the minimum desired acquisition frequency: once each 5 days. C1 UNIV MARYLAND,COLA,COLLEGE PK,MD 20742. VERSAR INC,COLUMBIA,MD. UNIV GEORGIA,GRIFFIN,GA 30223. UNIV WYOMING,LARAMIE,WY 82071. UNIV NEBRASKA,LINCOLN,NE 68588. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HALL, FG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 18 TC 30 Z9 31 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB-MAR PY 1991 VL 35 IS 2-3 BP 187 EP 199 DI 10.1016/0034-4257(91)90011-T PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FR683 UT WOS:A1991FR68300010 ER PT J AU RANSON, KJ IRONS, JR DAUGHTRY, CST AF RANSON, KJ IRONS, JR DAUGHTRY, CST TI SURFACE ALBEDO FROM BIDIRECTIONAL REFLECTANCE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID HEMISPHERICAL REFLECTANCE; VEGETATION CANOPIES; SENSOR; LAND; EOS AB Total hemispherical shortwave reflectance (albedo) is a major parameter of interest for studies of land surface climatology and global change. Efforts to estimate albedo from remote sensing data have been constrained by the available instrumentation that typically provide observations of reflected radiance from a single view direction in narrow spectral bands. However, the capability to obtain multiple angle observations over the shortwave region is planned for Earth Observing System sensors. In this paper, methods for estimating albedo from multiple angle, discrete wavelength band radiometer measurements are examined. The methods include a numerical integration technique and the integration of an empirically derived equation for bidirectional reflectance. The validity of the described techniques is examined by comparing albedo computed from multiband radiometer data with simultaneously acquired pyranometer data from vegetated and bare soil surfaces. Shortwave albedo estimated from both techniques agree favorably with the independent pyranometer measurements. Absolute root mean square errors were 0.5% or less for both grass sod and bare soil surfaces. C1 USDA ARS,BELTSVILLE AGR RES CTR,REMOTE SENSING RES LAB,BELTSVILLE,MD 20705. RP RANSON, KJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. RI Irons, James/D-8535-2012; Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 23 TC 46 Z9 52 U1 0 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB-MAR PY 1991 VL 35 IS 2-3 BP 201 EP 211 DI 10.1016/0034-4257(91)90012-U PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FR683 UT WOS:A1991FR68300011 ER PT J AU ENGMAN, ET AF ENGMAN, ET TI APPLICATIONS OF MICROWAVE REMOTE-SENSING OF SOIL-MOISTURE FOR WATER-RESOURCES AND AGRICULTURE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SURFACE-ROUGHNESS; RADIOMETER; RADIATION; COVER AB There has been significant progress in the application of microwave remote sensing for measuring soil moisture. Both passive and active systems have demonstrated the capability to measure soil moisture, and there have been a number of studies using aircraft and spaceborne data that have demonstrated its usefulness for agricultural and hydrologic applications. However, there are still several unresolved questions regarding the optimal instrument configuration and other target characteristics such as roughness and vegetation. In addition, the most likely disciplines for using these data, agriculture and hydrology, do not currently possess adequate models or procedures to use this new technology. RP ENGMAN, ET (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,CODE 974,GREENBELT,MD 20771, USA. NR 42 TC 68 Z9 70 U1 3 U2 12 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB-MAR PY 1991 VL 35 IS 2-3 BP 213 EP 226 DI 10.1016/0034-4257(91)90013-V PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FR683 UT WOS:A1991FR68300012 ER PT J AU GOWARD, SN MARKHAM, B DYE, DG DULANEY, W YANG, JL AF GOWARD, SN MARKHAM, B DYE, DG DULANEY, W YANG, JL TI NORMALIZED DIFFERENCE VEGETATION INDEX MEASUREMENTS FROM THE ADVANCED VERY HIGH-RESOLUTION RADIOMETER SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID LEAF-AREA INDEX; SATELLITE DATA; AVHRR DATA; METEOROLOGICAL SATELLITE; CALIBRATION; RADIATION; PHOTOSYNTHESIS; REFLECTANCE; SENSITIVITY; ABSORPTION AB The potential of computing normalized difference vegetation index (NDVI) measurements from the global, daily observations collected by the NOAA Advanced Very High Resolution Radiometer (AVHRR) has created great interest in the use of these data sets to study global biospheric dynamics. Initial qualitative studies demonstrated this potential but the move to quantitative assessments is hindered by limited understanding of the performance characteristics of the AVHRR observations relative to surface vegetation conditions. Factors related to instrument precision and calibration, atmospheric attenuation and off-nadir viewing create deviations of the NDVI observations unrelated to vegetation dynamics. Deviations in excess of 50% between the satellite and equivalent ground observations are possible if no effort is made to account for these effects. In addition, off-nadir viewing causes spatio-temporal variations in the measurements and cloud occurrence reduces temporal resolution below the AVHRR's daily repeat cycle. It appears possible to reduce these errors to approximately +/- 10% (+/- 0.1 NDVI) with at least a monthly time resolution if all of the observation attributes are addressed adequately. Much of the remaining error resides in atmospheric variability, uncertainties in off-nadir views and loss of sensor precision of large solar zenith angles. A global measure of vegetation green foliage dynamics with a measurement precision of +/- 10% and a monthly time resolution may not yet meet the exacting needs of some biospheric modelers, but it is, in fact, remarkable, considering that this possibility was not even conceived when the AVHRR was designed. Further refinement of global remotely sensed vegetation foliage measurement precision appears possible and should be the primary focus for terrestrial remote sensing research in the next decade. C1 NASA,GODDARD SPACE FLIGHT CTR,TERRESTRIAL PHYS LAB,GREENBELT,MD 20771. RP GOWARD, SN (reprint author), UNIV MARYLAND,DEPT GEOG,GLOBAL REMOTE SENSING STUDIES LAB,1113 LEFRAK HALL,COLLEGE PK,MD 20742, USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 77 TC 301 Z9 317 U1 6 U2 28 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB-MAR PY 1991 VL 35 IS 2-3 BP 257 EP 277 DI 10.1016/0034-4257(91)90017-Z PG 21 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FR683 UT WOS:A1991FR68300015 ER PT J AU PARMAR, DS AF PARMAR, DS TI A NOVEL BOUNDARY-LAYER SENSOR UTILIZING DOMAIN SWITCHING IN FERROELECTRIC LIQUID-CRYSTALS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A new sensor for optical detection of shear stress field induced by air or gas flow on a rigid surface is reported. The sensor uses the novel effects of shear induced optical switching in ferroelectric liquid crystals. The principle of operation of the sensor is described and a theoretical model for the optical response to shear stress is given. Director dynamics and system-free energy considerations predict a system response time almost-equal-to 10 ns for an applied shear stress step of almost-equal-to 700 Torr. A thin (almost-equal-to 1 mu-m) ferroelectric liquid crystal film coated on a flat glass model surface is exposed to gas flow from a micro wind tunnel attached to the polarizing microscope employed for optical measurements. Schlieren texture of the thin film consists of two stable domains separated by a domain wall. Gas or air flow on the liquid crystal surface induces director reorientation resulting in optical contrast. Transmitted and reflected light intensities from polarization microscopy provide measurement of the flow parameters. System response time tau approximately 150 mu-s has been estimated from the material viscosity and the time variation of the applied shear stress in the experiment. Optical response is linear for applied differential pressures up to almost-equal-to 800 Torr beyond which it tends to saturate. Second-order nonlinear effects are observed for flow rates beyond almost-equal-to 42 l/min. The configuration used in the present method overcomes many of the limitations of similar measuring techniques including those using cholesteric liquid crystals. The present method offers a preferred alternative for flow visualization and skin friction measurements in wind-tunnel experiments on laminar boundary layer transition investigations. RP PARMAR, DS (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 10 TC 12 Z9 12 U1 0 U2 5 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 1991 VL 62 IS 2 BP 474 EP 479 DI 10.1063/1.1142090 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EW414 UT WOS:A1991EW41400028 ER PT J AU DEBERGH, C BEZARD, B OWEN, T CRISP, D MAILLARD, JP LUTZ, BL AF DEBERGH, C BEZARD, B OWEN, T CRISP, D MAILLARD, JP LUTZ, BL TI DEUTERIUM ON VENUS - OBSERVATIONS FROM EARTH SO SCIENCE LA English DT Article ID ATMOSPHERE; HYDROGEN; ABUNDANCE; ESCAPE; MODEL; MARS; WET AB Absorption lines of HDO and H2O have been detected in a 0.23-wave number resolution spectrum of the dark side of Venus in the interval 2.34 to 2.43 micrometers, where the atmosphere is sounded in the altitude range from 32 to 42 kilometers (8 to 3 bars). The resulting value of the deuterium-to-hydrogen ratio (D/H) is 120 +/- 40 times the telluric ratio, providing unequivocal confirmation of in situ Pioneer Venus mass spectrometer measurements that were in apparent conflict with an upper limit set from International Ultraviolet Explorer spectra. The 100-fold enrichment of the D/H ratio on Venus compared to Earth is thus a fundamental constraint on models for its atmospheric evolution. C1 LOWELL OBSERV,FLAGSTAFF,AZ 86001. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. CALTECH,JET PROP LAB,PASADENA,CA 91109. INST ASTROPHYS,F-75014 PARIS,FRANCE. RP DEBERGH, C (reprint author), OBSERV PARIS,DEPT RECH SPATIALE,SECT MEUDON,F-92195 MEUDON,FRANCE. NR 30 TC 97 Z9 97 U1 1 U2 6 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 1 PY 1991 VL 251 IS 4993 BP 547 EP 549 DI 10.1126/science.251.4993.547 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EV459 UT WOS:A1991EV45900046 PM 11538265 ER PT J AU LAVERY, JE AF LAVERY, JE TI SOLUTION OF STEADY-STATE, 2-DIMENSIONAL CONSERVATION-LAWS BY MATHEMATICAL-PROGRAMMING SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE BURGERS EQUATION; CONSERVATION LAW; FINITE-VOLUME METHOD; L1 PROCEDURE; MATHEMATICAL PROGRAMMING; NONSINGULAR PERTURBATION; SINGULAR PERTURBATION; SHOCK; STEADY STATE; 2-DIMENSIONAL ID DIFFERENCE-SCHEMES; ALGORITHM; EQUATION; L1 AB Solution of steady-state scalar conservation laws [f(u)]x + pi[f(u)]y = 0 (tau-constant) on the unit square is considered for the two cases f(u) = u and u2. Piecewise constant Dirichlet conditions producing shocked solutions are given on the boundary of the unit square. A nonsingular perturbation 2-epsilon-u (epsilon a sufficiently small positive number), rather than a singular perturbation such as -epsilon(u(xx) + u(yy)), is added to the conservation law. The perturbed equation is discretized in a finite-volume sense on each of the cells of a grid of mm equal rectangular cells (m in the x-direction and n in the y-direction). Numerical values of u are located at the cell vertices. The arclength and area integrals of the finite-volume formulas are discretized by the trapezoidal rule. A system of mn equations results for the (m - 1)(n - 1) unknown values of u in the interior of the domain. This system is solved in the l1 sense; that is, the sum of the absolute values of the residuals of the equations is minimized. An algorithm requiring only O(mn) operations is introduced to solve this mathematical programming problem. The numerical solutions have discontinuities in or near the cells containing the shocks of the physically relevant solutions of the original conservation laws and are O(epsilon) approximations of these solutions. A complete theory for the linear case f(u) = u and computational results for the nonlinear case f(u) = u2 are presented. The l1 procedure captures boundary shocks as well as oblique and even zigzag interior shocks in one cell. The results presented here demonstrate that the l1 procedure is a robust, efficient, and highly accurate numerical procedure for solving certain two-dimensional scalar conservation laws. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 19 TC 6 Z9 6 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD FEB PY 1991 VL 28 IS 1 BP 141 EP 155 DI 10.1137/0728007 PG 15 WC Mathematics, Applied SC Mathematics GA EX039 UT WOS:A1991EX03900007 ER PT J AU SCROGGS, JS AF SCROGGS, JS TI PHYSICALLY MOTIVATED DOMAIN DECOMPOSITION FOR SINGULARLY PERTURBED EQUATIONS SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE DOMAIN DECOMPOSITION; ASYMPTOTICS; HYPERBOLIC-PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS ID BOUNDARY-VALUE-PROBLEMS; HYPERBOLIC CONSERVATION-LAWS; SCHEMES; GODUNOV AB A domain decomposition algorithm suitable for the efficient and accurate solution of a parabolic reaction-convection-diffusion equation with small parameter multiplying the diffusion term is presented. Convergence is established via maximum principle arguments. The equation arises in the modeling of laminar transonic flow. Decomposition into subdomains is accomplished via singular perturbation analysis which dictates regions where certain reduced equations may be solved in place of the full equation, effectively preconditioning the problem. This paper concentrates on the theoretical basis of the method, establishing local and global a priori error bounds. RP SCROGGS, JS (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,MAIL STOP 132C,HAMPTON,VA 23665, USA. NR 30 TC 7 Z9 7 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD FEB PY 1991 VL 28 IS 1 BP 168 EP 178 DI 10.1137/0728009 PG 11 WC Mathematics, Applied SC Mathematics GA EX039 UT WOS:A1991EX03900009 ER PT J AU CARTER, RG AF CARTER, RG TI ON THE GLOBAL CONVERGENCE OF TRUST REGION ALGORITHMS USING INEXACT GRADIENT INFORMATION SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE UNCONSTRAINED OPTIMIZATION; TRUST REGION METHODS; INEXACT GRADIENTS; GLOBAL CONVERGENCE ID OPTIMIZATION AB Trust region algorithms are an important class of methods that can be used to solve unconstrained optimization problems. Strong global convergence results are demonstrated for a class of methods where the gradient values are approximated rather than computed exactly, provided they obey a simple relative error condition. No requirement is made that gradients be recomputed to successively greater accuracy after unsuccessful iterations. C1 RICE UNIV,DEPT MATH SCI,HOUSTON,TX 77251. RP CARTER, RG (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 15 TC 38 Z9 38 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD FEB PY 1991 VL 28 IS 1 BP 251 EP 265 DI 10.1137/0728014 PG 15 WC Mathematics, Applied SC Mathematics GA EX039 UT WOS:A1991EX03900014 ER PT J AU BECKMAN, B AF BECKMAN, B TI A SCHEME FOR LITTLE LANGUAGES IN INTERACTIVE GRAPHICS SO SOFTWARE-PRACTICE & EXPERIENCE LA English DT Article DE EXTENSION LANGUAGES; SCHEME; INTERACTIVE GRAPHICS; SOFTWARE ENGINEERING AB Programming environments for interactive graphics software typically have a multiplicity of tools and applications. Many of these programs contain ad hoc 'little language' interpreters1 that do many similar things in needlessly different ways. In particular, many little languages have, in addition to their special-purpose constructs, vestigial support for ordinary programming, such as variables, loops and conditionals. If a single, standard programming language were the basis for all these little languages, they could have complete, coherent programming semantics; they could communicate with each other more easily; no design work for basic constructs would be needed; and interpreter implementation work would be saved. The approach of reusing and extending the same core language and interpreter for a variety of little languages is the extension language approach. Scheme is proposed as a good choice for such a core language. Scheme is a simple, elegant, high-level programming language. Extendable implementations are readily available in C source form. Example applications in Scheme from interactive graphics are presented that would be nearly impossible to code in a typical scripting language and very tedious to code in a lower-level implementation language such as C. RP BECKMAN, B (reprint author), CALTECH,JET PROP LAB,INFORMAT SYST ENGN SECT,COMP GRAPH LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 36 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0038-0644 J9 SOFTWARE PRACT EXPER JI Softw.-Pract. Exp. PD FEB PY 1991 VL 21 IS 2 BP 187 EP 207 DI 10.1002/spe.4380210206 PG 21 WC Computer Science, Software Engineering SC Computer Science GA EW865 UT WOS:A1991EW86500005 ER PT J AU SAFIE, FM HAGE, RT AF SAFIE, FM HAGE, RT TI A SIMULATION-MODEL FOR RISK ASSESSMENT OF TURBINE-WHEELS SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE RISK ASSESSMENT; INSPECTION MODEL; SIMULATION MODEL; SENSITIVITY ANALYSIS; AUXILIARY POWER UNIT AB A simulation model has been successfully developed to evaluate the risk of the space shuttle auxiliary power unit (APU) turbine wheels for a specific inspection policy. Besides being an effective tool for risk/reliability evaluation, the simulation model also allows the analyst to study the trade-offs between wheel reliability, wheel life, inspection interval, and rejection crack size. For example, in the APU application, sensitivity analysis results showed that the wheel life limit has the least effect on wheel reliability when compared to the effect of the inspection interval and the rejection crack size. In summary, the simulation model developed represents a flexible tool to predict turbine wheel reliability and study the risk under different inspection policies. RP SAFIE, FM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAIL STOP CT13,HUNTSVILLE,AL 35812, USA. NR 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 108 EP 111 DI 10.1109/ARMS.1991.154423 PG 4 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300019 ER PT J AU GONZALEZ, CC THOMAS, VC STONE, JM AF GONZALEZ, CC THOMAS, VC STONE, JM TI EVALUATION OF SPACECRAFT PRODUCT ASSURANCE REQUIREMENTS AND FLIGHT PERFORMANCE HISTORY SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE TREND ANALYSIS; IN-FLIGHT ANOMALIES; FLIGHT ANOMALY REPORT; PRODUCT ASSURANCE REQUIREMENT; SPACECRAFT; ANOMALY CAUSE; SUBSYSTEM; HARDWARE TYPE AB The Jet Propulsion Laboratory (JPL) has undertaken a task to relate long duration, space flight hardware performance to specific product assurance requirements established during the hardware development process. This paper describes the approach that JPL is using to correlate in-flight and ground test hardware failures to critical product assurance practices implemented on a given flight project. The first step in this effort has been to collect, and convert into a convenient format, in-flight problem, failure and anomaly data. A characterization of a subset of this anomaly data base, focusing on anomaly causes, time dependence and subsystem affected is presented in this paper. Preliminary results from an analysis of the data set indicate: 1. Parts/materials and design were the most common anomaly causes. 2. The anomaly data, classified by cause and subsystem, shows that anomalies caused by electronic parts are most significant in the telemetry/data handling/communications and thermal subsystems and those caused by design are most significant in the guidance and control and power subsystems. 3. Factors such as spacecraft complexity need to be accounted for in any data analysis. 4. The largest percentage of anomalies occurred in the instrument/payload and Telemetry/Data Handling/Communications subsystems. 5. The greatest number of anomalies occurred in electrical/electronic hardware. RP GONZALEZ, CC (reprint author), CALTECH,JET PROP LAB,RELIABIL ENGN SECT,TECH STAFF,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 149 EP 155 DI 10.1109/ARMS.1991.154428 PG 7 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300024 ER PT J AU DUNN, WR FOLSOM, RA GREEN, OR AF DUNN, WR FOLSOM, RA GREEN, OR TI LATENT-FAILURE RISK ESTIMATES FOR COMPUTER CONTROL SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE LATENT FAILURE; COMPUTER CONTROL; RISK; PROBABILITY; SAFETY; MONITORING AB The possibility of spurious computer (or human) commands to a safety-critical control function is often countered by using hardwired protection circuitry in series with the primary control outputs. However, it is not always recognized that continuous monitoring is needed to avoid a latent-failure hazard (Ref. 1) if the protection circuitry should fail. It is shown in the paper that critical computer controls employing unmonitored safety circuits are unsafe. Analysis supporting this result leads to two additional, important conclusions: 1) annual maintenance checks of safety circuit function do not, as widely believed, eliminate latent failure risk; 2) safety risk remains even if multiple, series-connected protection circuits are employed. Finally, it is shown analytically that latent failure risk is eliminated when continuous monitoring is employed. The models and metrics employed in the paper can be applied by designers and reliability analysts in evaluating their specific computer control applications. RP DUNN, WR (reprint author), UNIV SO COLORADO,NASA,AMES RES CTR,M-S 218-6,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 531 EP 535 DI 10.1109/ARMS.1991.154493 PG 5 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300090 ER PT J AU WHITE, AL AF WHITE, AL TI AN ERROR BOUND FOR INSTANTANEOUS COVERAGE SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE RELIABILITY ESTIMATION; SEMI-MARKOV MODEL; MODEL SIMPLIFICATION; ERROR BOUND; RECONFIGURABLE SYSTEM AB An error bound is derived for a reliability model approximation method. The approximation method is appropriate for the semi-Markov models of reconfigurable systems that are designed to achieve extremely high reliability. The semi-Markov models of these system are complex, and a significant amount of their complexity arises from the detailed descriptions of the reconfiguration processes. The reliability model approximation method consists of replacing a detailed description of a reconfiguration process with the probabilities of the possible outcomes of the reconfiguration process. These probabilities are included in the model as instantaneous jumps from the fault-occurrence state. Since little time is spent in the reconfiguration states, instantaneous jumps are a close approximation to the original model. This approximation procedure is shown to produce an overestimation for the probability of system failure, and an error bound is derived for this overestimation. RP WHITE, AL (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 587 EP 591 DI 10.1109/ARMS.1991.154503 PG 5 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300100 ER PT J AU GARDNER, SD HOFLUND, GB SCHRYER, DR UPCHURCH, BT AF GARDNER, SD HOFLUND, GB SCHRYER, DR UPCHURCH, BT TI CHARACTERIZATION STUDY OF SILICA-SUPPORTED PLATINIZED TIN OXIDE CATALYSTS USED FOR LOW-TEMPERATURE CO OXIDATION - EFFECT OF PRETREATMENT TEMPERATURE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID POLYCRYSTALLINE TIN; SURFACE; FILMS; SPECTROSCOPY; XPS AB Pt/SnO2 surfaces supported on SiO2, used for low-temperature CO oxidation in CO2 lasers, have been characterized before and after reduction in CO at 125 and 250-degrees-C using ion scattering spectroscopy (ISS) and X-ray photoelectron spectroscopy (XPS). XPS indicates that the Pt is present initially as PtO and PtO2 and small amounts of Pt(OH)2 and metallic Pt. Reduction at 125-degrees-C converts most of the Pt to Pt(OH)2 while reduction at 250-degrees-C converts most of the Pt to metallic Pt. The SnO2 appears to be partially reduced to SnO. ISS results suggest that during the 250-degrees-C reduction the Pt and Sn in the outermost atomic layer of the catalyst are covered by impurities originating from the silica substrate whereas reduction at 125-degrees-C enriches the outermost atomic layer in Pt and Sn. Both the ISS and XPS data are consistent with the assertion that a Pt/Sn alloy forms during the reduction. The surface dehydration, change of Pt chemical state, and migration of substrate impurities over surface Pt and Sn appear to explain why a CO pretreatment at 250-degrees-C produces inferior CO oxidation activity compared to a 125-degrees-C CO pretreatment. C1 UNIV FLORIDA,DEPT CHEM ENGN,GAINESVILLE,FL 32611. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 34 TC 45 Z9 45 U1 1 U2 9 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 24 PY 1991 VL 95 IS 2 BP 835 EP 838 DI 10.1021/j100155a064 PG 4 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600064 ER PT J AU MAGALHAES, JA BORUCKI, WJ AF MAGALHAES, JA BORUCKI, WJ TI SPATIAL-DISTRIBUTION OF VISIBLE LIGHTNING ON JUPITER SO NATURE LA English DT Article ID ELECTROSTATIC DISCHARGES; JOVIAN ATMOSPHERE; VOYAGER-1; VENUS AB SPACECRAFT observations have provided evidence for the existence of lightning on Venus 1-3, Jupiter 4,5, Saturn 6,7 and Uranus 8. Little is known, however, about the global distribution of lightning on these planets because of the limited spatial resolution and areal coverage of these previous detections, which have principally involved radio-frequency measurements. Two long-exposure images obtained by the Voyager 1 spacecraft of a small area on the nightside of Jupiter have provided the only previously studied imaging observations of lightning on another planet9,10. Here we present an analysis of all suitable Voyager images of Jupiter and evaluate the horizontal spatial distribution of visible lightning over most of one hemisphere. Essentially all the detectable activity is confined to very narrow latitude bands at 13.5-degrees-N and 49-degrees-N. The active regions at 49-degrees-N are the brightest, most numerous and periodic in longitude. Activity at this latitude is long-lived and is most likely associated with moist convective regions deep in Jupiter's atmosphere. The longitudinal periodicity of the lightning storms may represent the effects of a planetary scale atmospheric wave trapped at the depth of the moist convection 11,12. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP MAGALHAES, JA (reprint author), STANFORD UNIV,CTR RADAR ASTRON,223 DURAND BLDG,STANFORD,CA 94305, USA. NR 26 TC 26 Z9 26 U1 1 U2 4 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 24 PY 1991 VL 349 IS 6307 BP 311 EP 313 DI 10.1038/349311a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EU501 UT WOS:A1991EU50100044 ER PT J AU BRIGHTWELL, G GREGORY, R AF BRIGHTWELL, G GREGORY, R TI STRUCTURE OF RANDOM DISCRETE SPACETIME SO PHYSICAL REVIEW LETTERS LA English DT Article AB The usual picture of spacetime consists of a continuous manifold, together with a metric of Lorentzian signature which imposes a causal structure. We consider a model in which spacetime consists of a discrete set of points taken at random from a manifold, with only the causal structure remaining. Using only this structure, we show how to construct a metric, how to define the effective dimension, and how such quantities may depend on the scale of measurement. We discuss possible desirable features of the model. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP BRIGHTWELL, G (reprint author), UNIV LONDON LONDON SCH ECON & POLIT SCI,DEPT MATH,HOUGHTON ST,LONDON WC2A 2AE,ENGLAND. NR 7 TC 54 Z9 54 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 21 PY 1991 VL 66 IS 3 BP 260 EP 263 DI 10.1103/PhysRevLett.66.260 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000004 ER PT J AU DEVI, VM BENNER, DC SMITH, MAH RINSLAND, CP AF DEVI, VM BENNER, DC SMITH, MAH RINSLAND, CP TI MEASUREMENTS OF AIR-BROADENED, N2-BROADENED, AND O2-BROADENED HALF-WIDTHS AND PRESSURE-INDUCED LINE SHIFTS IN THE NU-3 BAND OF (CH4)-C-134 SO APPLIED OPTICS LA English DT Article ID METHANE LINES; LORENTZ WIDTH; FREQUENCY; NITROGEN; CH4; COEFFICIENTS; PARAMETERS; HYDROGEN; HELIUM; ARGON AB Air-, nitrogen-, and oxygen-broadened halfwidth and pressure-induced line shift coefficients have been measured for over seventy-five individual vibration-rotation transitions in the nu-3 fundamental band of (CH4)-C-13 at 3-mu-m from room temperature IR laboratory absorption spectra recorded at a 0.01-cm-1 resolution with a Fourier transform spectrometer. Transitions up to J" = 13 in the P-branch and J" = 7 in the R-branch were analyzed using a nonlinear least-squares curve fitting technique assuming a Voigt line shape. From the analysis, we have determined the mean ratios of air- to nitrogen-broadened and air- to oxygen-broadened halfwidth coefficients obtained for the same transitions as 1.00 +/- 0.03 and 1.06 +/- 0.04, respectively. The measured pressure shift coefficients were predominantly negative, and the mean and standard deviation values for air-, nitrogen-, and oxygen-broadened shifts were -0.0067 +/- 0.0032, -0.0068 +/- 0.0041, and -0.0066 +/- 0.0028 cm-1 atm-1, respectively. Comparisons are made with the results obtained for similar transitions in the nu-3 band of (CH4)-C-12 and the nu-4 band of (CH4)-C-13. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665. RP DEVI, VM (reprint author), COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23185, USA. NR 24 TC 26 Z9 26 U1 1 U2 4 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 1991 VL 30 IS 3 BP 287 EP 304 PG 18 WC Optics SC Optics GA EV207 UT WOS:A1991EV20700004 PM 20581981 ER PT J AU CIOFFI, DF SHULL, JM AF CIOFFI, DF SHULL, JM TI SIMULATIONS OF THE SUPERNOVA-DOMINATED INTERSTELLAR-MEDIUM IN DISK GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INTERSTELLAR MATTER; NEBULAE, SUPERNOVA REMNANTS ID LARGE MAGELLANIC CLOUD; ADIABATIC BLAST WAVES; INTER-STELLAR MEDIUM; H-I HALO; NOVA REMNANTS; MOLECULAR CLOUDS; STAR FORMATION; SPHERICAL CLOUDS; GASEOUS HALO; CORONAL GAS AB preventing the establishment of long-lived "tunnel" networks of hot rarefied gas. remnants (SNRs). We have developed a computer stimulation that uses standard SNR evolutionary solutions to redistribute mass and energy throughout a rectangular, three-level grid. This model includes bremsstrahlung or metal cooling, creation and evaporation of clouds, mass injection to and return from a galactic halo, multiple correlated SNRs, and internally determined SNR lifetimes; we neglected magnetic fields and cooling by dust. We have confirmed the suspicion that spatial correlation of supernova sites can increase the global evolution rate of the metal-cooled ISM. Porosity theory is unable to predict the topology of the interstellar medium because it does not account for mass transport, averaging 0.007 M. pc-2 Myr-1 and 2 M. pc-2 into the halo. In "primeval" (zero metal abundance) galaxies, the enhanced mass transport by bremsstrahlung-cooled remnants continually agitates the ISM, preventing the establishment of long-lived "tunnel" networks of hot rarefied gas. One cannot use the simple SNR number-radius relation to infer evolutionary histories, because of its implicit assumptions of a homogeneous mass density and constant SNR lifetimes; a simple N(R) histogram conveys more information. If SNR shells are the main source of cold clouds in present-day galaxies, the initial size of the clouds can determine the global structure of the ISM. With small clouds (<< 1 pc) that are easily evaporated, less than 25% of interstellar material will be "locked up" in atomic hydrogen, leaving most of the material in a warm or hot phase at high pressure. If the created clouds are of the more usually assumed size (approximately 1 pc), about 70% of the disk mass will remain in cold, cloudy state, and the pressure assumes more conventional interstellar values. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO 80309. NATL INST STAND & TECHNOL,BOULDER,CO. CTR ASTROPHYS & SPACE ASTRON,BOULDER,CO. NR 113 TC 30 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP 96 EP 114 DI 10.1086/169606 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800010 ER PT J AU DOPITA, MA MEATHERINGHAM, SJ AF DOPITA, MA MEATHERINGHAM, SJ TI PHOTOIONIZATION MODELING OF MAGELLANIC CLOUD PLANETARY-NEBULAE .1. SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, MAGELLANIC CLOUDS; NEBULAE, PLANETARY ID H-II REGIONS; INTERMEDIATE-MASS STARS; THEORETICAL-MODELS; INTERNAL DYNAMICS; ANGULAR DIAMETERS; CHARGE-TRANSFER; GALACTIC BULGE; STELLAR WINDS; COMPLEX FLOWS; OUTER REGIONS AB We present the results of self-consistent photoionization modeling of a first sample of 38 Magellanic Cloud planetary nebulae (PN). From these models, we have constructed a Hertzsprung-Russell (H-R) Diagram for the central stars, and we have derived both the chemical abundances and the nebular parameters. We find that effective temperatures, T(eff), derived from a nebular excitation analysis, agree well with the temperatures derived by the classical Zanstra method. However, the nebular analysis method allows us to derive the effective temperatures of hot central stars, as well as in the case of the cooler stars to which the Zanstra method is generally restricted. We find a very good linear correlation between log (T(eff)) and the excitation class. From their positions on the H-R diagram, we conclude that the majority of the central stars in this sample have masses between 0.55 and 0.7 M. and are observed during their hydrogen-burning excursion towards high temperatures. Optically thin objects are found scattered throughout the H-R diagram, but tend to have a somewhat smaller mean mass. A few objects are found to have central stars with very high effective temperatures and masses in excess of 0.7 M.. These objects tend to be type I PN, with evidence of a third dredge-up episode resulting in correlated He and N abundance enhancements. The nebular mass of the optically thick objects is closely correlated with the nebular radius, and PN with nebular masses in excess of 1 M. are observed. The velocity of expansion of the nebula is very well-correlated with the position of the central star on the H-R diagram, and is evidence for continual acceleration of the nebular shell during the transition toward high T(eff). Excluding the type I PN, the mean abundances derived for the LMC and SMC agree very well with the mean abundances previously derived from observation of H II regions and evolved radiative supernova remnants. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP DOPITA, MA (reprint author), AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,INST ADV STUDIES,WESTON CREEK,WODEN,ACT 2611,AUSTRALIA. RI Dopita, Michael/P-5413-2014 OI Dopita, Michael/0000-0003-0922-4986 NR 61 TC 76 Z9 76 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP 115 EP 125 DI 10.1086/169607 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800011 ER PT J AU KNACKE, RF LARSON, HP AF KNACKE, RF LARSON, HP TI WATER-VAPOR IN THE ORION MOLECULAR CLOUD SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERSTELLAR, ABUNDANCES; INTERSTELLAR, MOLECULES; NEBULAE, ORION NEBULA ID GAS-PHASE CHEMISTRY; DENSE INTERSTELLAR CLOUDS; MICRON SPECTROSCOPY; COMPLEX-MOLECULES; DEUTERATED WATER; LINE EMISSION; MODEL; H2O; KL; ABUNDANCES AB We report infrared observations of interstellar gas-phase H2O in the spectrum of the BN object in Orion. There are absorptions (S/N = 2-5) at the positions of four of the strong lines in the 000-001 upsilon-3 (2.66-mu-m) vibration-rotation band. The new observations corroborate the detection reported by Knacke, Larson, and Noll. With an estimated excitation temperature of 150 K, the column density of gaseous H2O toward BN in the OMC-1 cloud is (2 +/- 1) x 10(17) cm-2. The intensities of the lines imply an ortho/para ratio of 1 +/- 0.5 indicating recent sublimation of H2O from low-temperature grains. The results give gas-phase abundance ratios of H2O/CO almost-equal-to 0.03 +/- 0.02 and HDO/H2O = 10(-3)-10(-4) toward BN. The velocities of the H2O absorptions agree with those of the ridge source and CO outflow, but the position along the line of sight is not well constrained. The gas/solid ratio is H2O gas/H2O(ice) less-than-or-equal-to 0.05. Less than 1% of the oxygen is in H2O gas (assuming total cosmic abundance). Most of the H2O in the line of sight to BN, and by inference in quiescent regions of molecular clouds generally, is frozen on grains. C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NR 37 TC 26 Z9 26 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 20 PY 1991 VL 367 IS 1 BP 162 EP 167 DI 10.1086/169612 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800016 ER PT J AU PETUCHOWSKI, SJ BENNETT, CL AF PETUCHOWSKI, SJ BENNETT, CL TI A SEARCH FOR VIBRATIONALLY EXCITED H2O AT 68 GHZ SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERSTELLAR, MOLECULES; LINE IDENTIFICATIONS; RADIO SOURCES, LINES ID LATE-TYPE STARS; MOLECULAR LINE SURVEY; EMISSION-LINES; ORION-KL; INFRARED-EMISSION; MILLIMETER-WAVE; WATER MASER; CLOUD; CO; SPECTRUM AB Water vapor may be one of the most abundant constituents of shocked molecular clouds. The nonequilibrium distribution of population among its rotational energy states requires the observation of a multiplicity of transitions to constrain its abundance and excitation state. Flux limits are presented for emission due to the (010) 4(14) --> 3(21) rotational transition of ortho-H2O at 67.804 GHz in several nebular and stellar sources. Upper limits for a beam-averaged column density of H2O in its upsilon-2 vibrational manifold are derived for Orion BN-KL. Constraints placed by these observations on an internal source of infrared radiation in the Orion shock are discussed. RP PETUCHOWSKI, SJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 685,GREENBELT,MD 20771, USA. NR 38 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP 168 EP 172 DI 10.1086/169613 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800017 ER PT J AU GRADY, CA BRUHWEILER, FC CHENG, KP CHIU, WA KONDO, Y AF GRADY, CA BRUHWEILER, FC CHENG, KP CHIU, WA KONDO, Y TI THE CIRCUMSTELLAR DISKS OF BETA-PICTORIS ANALOGS SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, SOURCES; STARS, BE; STARS, CIRCUMSTELLAR SHELLS; ULTRAVIOLET, SPECTRA ID IRAS OBSERVATIONS; SHELL STARS; CA-II; VELOCITIES; LINE AB A survey using data from the International Ultraviolet Explorer (IUE) of previously known B and A shell stars with IRAS detections has resulted in the identification of three stars. HD 93563, sigma-Her, and 51 Oph, which have spectral signatures of infalling circumstellar plasma similar to beta-Pic. Two of these systems have infrared flux distributions indicating the presence of circumstellar dust disks, while the other, HD 93563, has an infrared excess consistent with free-free emission from the plasma envelope. With the identification of three such systems, it is clear that infalling circumstellar plasma is more common than previously anticipated among late-type Beta shell stars. The detection of two dusty systems, apparently viewed nearly edge-on, provides additional nearby beta-Pic-like systems oriented favorably for quantitative study of both the dust and the gas envelopes. The absence of dust in one system, HD 93563, suggest that infalling plasma in these stars, and possibly also in beta-Pic itself, may not be due to either erosion of a dust disk or to high cometary bombardment rates, but may instead be linked to stellar activity. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP GRADY, CA (reprint author), CATHOLIC UNIV AMER,DEPT DIABET RES & TRAINING,WASHINGTON,DC 20064, USA. NR 37 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP 296 EP 301 DI 10.1086/169628 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800032 ER PT J AU ELITZUR, M MCKEE, CF HOLLENBACH, DJ AF ELITZUR, M MCKEE, CF HOLLENBACH, DJ TI RADIATIVE-TRANSFER IN ASTRONOMICAL MASERS .3. FILAMENTARY MASERS SO ASTROPHYSICAL JOURNAL LA English DT Article DE MASERS; RADIATIVE TRANSFER ID WATER MASER; ORION AB This paper, the last in a series, presents the complete solution of a filamentary master. The contribution of rays emanating from the filament sidewall is essential for the solution self-consistency during saturation. We develop an integral equation to calculate this contribution, devise an iteration scheme to solve it, and perform the first two iterations. The solution provides complete expressions for the distributions of intensity and flux across the source as functions of position and direction with regard to the axis. One consequence of radiation beaming, somewhat surprising at first, is that the filament appears smaller when viewed off-axis, at angles exceeding the cap's opening angle. From the detailed results we devise the number distribution of brightness temperatures in a large sample of randomly oriented filaments with an arbitrary distribution of lengths. A thorough comparison of the filamentary and spherical geometries is presented with possible observational tests to differentiate between the two. The effects of external radiation on the maser structure and intensity are also studied. Explicit expressions for the brightness and flux in this situation are provided, including detailed analysis of two interacting filaments and a foreground slab amplifying a background filament. We propose that the two giant bursts of H2O maser emission observed in W49 and Orion were the result of such interactions. RApid time variations reported for the Orion burst may best be explained with amplification of a background maser filament by a foreground maser slab, initially unsaturated. C1 UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP ELITZUR, M (reprint author), UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506, USA. NR 13 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 20 PY 1991 VL 367 IS 1 BP 333 EP 349 DI 10.1086/169632 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800036 ER PT J AU MAYR, HG CHAN, KL HARRIS, I SCHATTEN, K AF MAYR, HG CHAN, KL HARRIS, I SCHATTEN, K TI WHAT MAINTAINS THE ZONAL CIRCULATION IN PLANETARY-ATMOSPHERES SO ASTROPHYSICAL JOURNAL LA English DT Article DE PLANETS, ATMOSPHERES; PLANETS, INTERIOR; PLANETS, JUPITER; PLANETS, NEPTUNE; PLANETS, VENUS ID QUASI-AXISYMMETRIC CIRCULATION; MIXING-LENGTH THEORY; JUPITER; VOYAGER-2; ROTATION; VENUS; SUPERROTATION; CONVECTION; VALIDITY; DYNAMICS AB The latest Voyager observations have shown large zonal velocities in Neptune's atmosphere (order of 100 m s-1), with some indication of alternating jets. Similar wind velocities have also been observed on Venus and are characteristic of planetary atmospheres in general, which is remarkable considering that the available solar or internal heating varies by more than a factor of 1000. We discuss a simplified model of the planetary circulation which provides some qualitative understanding. The basic assumption is that the source driving the circulation is also generating the dissipating eddies which are simulated by diffusion. Thus, the magnitude and structure of the zonal circulation are independent both of the source and the dissipation rate. The zonal velocities are related to the speed of sound and are of comparable magnitude in different atmospheres; although the available heating varies by a large factor, nad the planetary parameters (angular velocity, radius, gravity, etc.) vary over a wide range. The alternating jets are described by a convective eigenmode which develops when energy transport out of the planetary interior is important, as is the case on Jupiter and Neptune (and Saturn). RP MAYR, HG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 26 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP 361 EP 366 DI 10.1086/169634 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800038 ER PT J AU NOMOTO, K KONDO, Y AF NOMOTO, K KONDO, Y TI CONDITIONS FOR ACCRETION-INDUCED COLLAPSE OF WHITE-DWARFS SO ASTROPHYSICAL JOURNAL LA English DT Article DE PULSARS; STARS-ACCRETION; STARS-BINARIES; STARS-NEUTRON; STARS-WHITE DWARFS; X-RAYS-BINARIES ID ELECTRON-CAPTURE SUPERNOVAE; 8-10 M. STARS; I SUPERNOVAE; EVOLUTION; BINARIES; PULSARS; MODELS AB Recent discovery of an unexpectedly large number of low-mass binary pulsars (LMBPs) in globular clusters has instigated active discussions on the evolutionary origin of binary pulsars. Prompted by the possibility that at least some of LMBPs originate from accretion-induced collapse (AIC) of white dwarfs, we reexamine whether or not AIC occurs for the new models of O + Ne + Mg white dwarfs and solid C + O white dwarfs that can ignite explosive nuclear burning at significantly lower central densities than in the previous models. We find that even with low densities, AIC is still much more likely than explosion for both types of white dwarfs. We present possible regions for AIC in a diagram of mass accretion rate versus initial mass of the white dwarf. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP NOMOTO, K (reprint author), UNIV TOKYO,FAC SCI,DEPT ASTRON,BUNKYO KU,TOKYO 113,JAPAN. RI Nomoto, Ken'ichi/A-4393-2011 NR 42 TC 228 Z9 231 U1 2 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1991 VL 367 IS 1 BP L19 EP L22 DI 10.1086/185922 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER079 UT WOS:A1991ER07900005 ER PT J AU THOMAS, GE MCPETERS, RD JENSEN, EJ AF THOMAS, GE MCPETERS, RD JENSEN, EJ TI SATELLITE-OBSERVATIONS OF POLAR MESOSPHERIC CLOUDS BY THE SOLAR BACKSCATTERED ULTRAVIOLET SPECTRAL RADIOMETER - EVIDENCE OF A SOLAR-CYCLE DEPENDENCE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NOCTILUCENT CLOUDS; WESTERN-EUROPE; MIDDLE ATMOSPHERE; NITRIC-OXIDE; CLIMATOLOGY; MODEL; THERMOSPHERE AB Measurements from space of the Earth's ultraviolet albedo are affected by scattering of sunlight from polar mesospheric clouds (PMC). We have examined 8 years of solar backscattered ultraviolet (SBUV) albedo data and find evidence of an annual occurrence of PMC in the summertime polar cap regions of both hemispheres. We have devised a cloud selection algorithm based upon the expected spectral properties of PMC scattering and show that the albedo residuals selected by this algorithm, at least above some threshold brightness, possess the basic properties of PMC with regard to their brightness levels, their seasonal characteristics, and latitude variation. Because of the uniform sampling of the polar caps, particularly in the southern hemisphere, it is possible to examine year-to-year variations in PMC activity. We find that a significant trend is present in the PMC occurrence frequency values over the period 1978 to 1986. The increase (up to a factor of 10 at some brightness levels) in the occurrence frequency from solar maximum to solar minimum conditions indicates an anticorrelation with solar activity, an effect that also appears to be present in noctilucent cloud sightings over the past several decades. Garcia [1989] suggested that PMC should be modulated by changes in the solar Lyman-alpha (121.6 nm) flux through its strong photodissociation control of upper mesospheric water vapor. Solar Lyman-alpha underwent a significant (50%) variation during this period. Our results confirm this expectation, and thus indirectly support the current theories of PMC formation. However, other influences such as long-term changes of mesopause temperature or dynamics cannot be ruled out. We have identified two kinds of hemispherical asymmetries: the first, that PMC in the northern hemisphere is significantly brighter than in the south is consistent with previous results derived from Solar Mesosphere Explorer data; and the second, that the solar cycle response in the south is more pronounced than in the north. We show that if PMC scattering is not taken into account in the SBUV ozone retrieval algorithm, systematic errors of order 10% can occur in derived ozone concentration in the 40-50 km region of the summer polar cap. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RP THOMAS, GE (reprint author), UNIV COLORADO, ATMOSPHER & SPACE PHYS LAB, BOULDER, CO 80309 USA. RI McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 45 TC 44 Z9 44 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 1991 VL 96 IS D1 BP 927 EP 939 DI 10.1029/90JD02312 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EV403 UT WOS:A1991EV40300004 ER PT J AU RINSLAND, CP GUNSON, MR FOSTER, JC TOTH, RA FARMER, CB ZANDER, R AF RINSLAND, CP GUNSON, MR FOSTER, JC TOTH, RA FARMER, CB ZANDER, R TI STRATOSPHERIC PROFILES OF HEAVY-WATER VAPOR ISOTOPES AND CH3D FROM ANALYSIS OF THE ATMOS SPACELAB-3 INFRARED SOLAR SPECTRA SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LINE PARAMETERS; NU-2 BANDS; FRACTIONATION; H2O; SPECTROSCOPY; ABSORPTION; HDO; CH4 AB Stratospheric volume mixing ratio profiles of (H2O)-O-18, (H2O)-O-17, HDO, and CH3D near latitudes of 30-degrees-N and 47-degrees-S have been retrieved from approximately 0.01-cm-1 resolution infrared solar occulation spectra recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Spacelab 3 shuttle mission (April 29 to May 6, 1985). Improved heavy isotope water vapor and CH3D spectroscopic parameters determined from approximately 0.005- to 0.01-cm-1 resolution room temperature laboratory spectra have been used in the retrievals. The profiles of the three water vapor isotopes show an increase in the volume mixing ratio with altitude over the range of measurements (20 to 54 km for (H2O)-O-18, 20 to 46 km for (H2O)-O-17, and 20 to 34 km for HDO). Deuterium-to-hydrogen and heavy-to-normal oxygen isotope ratio profiles have been calculated by dividing the retrieved isotopic profiles by the previously reported profiles of (H2O)-O-16 and CH4 obtained from the same spectral data and then referencing these results to the isotopic composition of standard mean ocean water (SMOW). At 20 km the O-18/O-16 ratio in H2O is slightly (approximately 8%) depleted relative to SMOW; this ratio increases with altitude and is slightly positive above approximately 36 km. No evidence has been found for the large O-18 enhancements reported previously. The O-17/O-16 water vapor results are similar to those for O-18/O-16. The ATMOS measurements show depletions of approximately 63% in the D/H content of water vapor near 20 km and an increase in this ratio with altitude up to 34 km. The D/H ratio in stratospheric methane is close to the isotopic ratio in SMOW over the 18 to 28 km altitude range. No differences between the water vapor or methane isotopic compositions at 30-degrees-N and 47-degrees-S were detected. The results are compared with previously reported measurements and calculations. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. UNIV LIEGE, INST ASTROPHYS, B-4000 LIEGE COINTE, BELGIUM. RP RINSLAND, CP (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL STOP 401A, HAMPTON, VA 23665 USA. NR 43 TC 59 Z9 59 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 1991 VL 96 IS D1 BP 1057 EP 1068 DI 10.1029/90JD02234 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EV403 UT WOS:A1991EV40300013 ER PT J AU GARY, BL KEIHM, SJ AF GARY, BL KEIHM, SJ TI MICROWAVE SOUNDING UNITS AND GLOBAL WARMING SO SCIENCE LA English DT Article ID CLIMATE RP GARY, BL (reprint author), CALTECH,JET PROP LAB,M-S T1182,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 7 TC 4 Z9 4 U1 0 U2 1 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 18 PY 1991 VL 251 IS 4991 BP 316 EP 317 DI 10.1126/science.251.4991.316 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ET678 UT WOS:A1991ET67800035 PM 17733289 ER PT J AU SPENCER, RW CHRISTY, JR AF SPENCER, RW CHRISTY, JR TI MICROWAVE SOUNDING UNITS AND GLOBAL WARMING - RESPONSE SO SCIENCE LA English DT Article C1 UNIV ALABAMA,JOHNSON RES CTR,HUNTSVILLE,AL 35899. RP SPENCER, RW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,CODE ES43,HUNTSVILLE,AL 35812, USA. NR 1 TC 2 Z9 2 U1 0 U2 1 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 18 PY 1991 VL 251 IS 4991 BP 317 EP 317 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ET678 UT WOS:A1991ET67800036 ER PT J AU BORDERIES, N AF BORDERIES, N TI URANUS THE PLANET, RINGS AND SATELLITES - MINER,ED SO NATURE LA English DT Book Review RP BORDERIES, N (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 1 TC 0 Z9 0 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 17 PY 1991 VL 349 IS 6306 BP 204 EP 204 DI 10.1038/349204b0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ET519 UT WOS:A1991ET51900043 ER PT J AU CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG GARRETT, BC SCHWENKE, DW AF CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG GARRETT, BC SCHWENKE, DW TI GLOBAL CONTROL OF SUPRATHRESHOLD REACTIVITY BY QUANTIZED TRANSITION-STATES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MECHANICAL REACTION PROBABILITIES; POTENTIAL-ENERGY SURFACE; THERMAL RATE CONSTANTS; H + H2; CHEMICAL-REACTIONS; TUNNELING CALCULATIONS; COLLINEAR REACTIONS; HYDROGEN MOLECULES; ADIABATIC THEORY; PHASE-SPACE AB We present evidence that the accurate quantum mechanical probability of the reaction of H with H-2 is globally controlled by quantized transition states up to very high energies. The quantized transition states produce steplike features in the cumulative reaction probability curves that are analyzed up to energies of 1.6 eV; the analysis clearly associates these steps (or ''thresholds'') with quantized dynamical bottlenecks that control the passage of reactive flux to products. We have assigned bend and stretch quantum numbers to the modes orthogonal to the reaction coordinate for all these transition states on the basis of threshold energies of semiclassical vibrationally adiabatic potential energy curves and vibrationally specific cumulative reaction probability densities. C1 UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Garrett, Bruce/F-8516-2011; schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 98 TC 97 Z9 98 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JAN 16 PY 1991 VL 113 IS 2 BP 486 EP 494 DI 10.1021/ja00002a016 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ET682 UT WOS:A1991ET68200016 ER PT J AU LEE, TJ RICE, JE AF LEE, TJ RICE, JE TI THEORETICAL CHARACTERIZATION OF TETRAHEDRAL N-4 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BASIS-SETS; ENERGY SURFACES; P4; N4; CONTRACTION; 1ST-ROW; SINGLET; ATOMS AB The tetrahedral (T(d)) form of the N4 molecule has been investigated via ab initio quantum mechanical methods. The lowest triplet state of N4 in the tetrahedral region of the potential energy surface, and the barrier separating T(d)N4 from two N2 molecules have also been examined. Both the transition state and 3A" state have C(s) symmetry. The singlet state of tetrahedral N4 is predicted to lie 13 kcal/mol below the 3A" state. The energy difference between T(d)N4 and two N2 molecules is accurately determined to be 186 kcal/mol while the barrier separating these species is found to be about 61 kcal/mol. The possibility that T(d)N4 may be used as a high energy density fuel is investigated and discussed. In addition, a highly accurate determination of the equilibrium structure, harmonic vibrational frequencies, and infrared intensities of T(d)N4 has been performed using large atomic natural orbital (ANO) basis sets in conjunction with the coupled-cluster single and double (CCSD) excitation level of theory and the CCSD (T) extension. The largest ANO basis sets used for N4 contain closed-integral-type functions. Analogous studies of the N2 molecule are presented in order to judge the reliability of the theoretical predictions for the experimentally unknown T(d)N4. C1 IBM CORP, DIV RES, ALMADEN RES CTR, SAN JOSE, CA 95102 USA. RP NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Rice, Julia/K-4928-2012; Lee, Timothy/K-2838-2012 OI Rice, Julia/0000-0001-5059-5127; NR 33 TC 118 Z9 118 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 15 PY 1991 VL 94 IS 2 BP 1215 EP 1221 DI 10.1063/1.460029 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EU592 UT WOS:A1991EU59200044 ER PT J AU GREEN, S DEFREES, DJ MCLEAN, AD AF GREEN, S DEFREES, DJ MCLEAN, AD TI CALCULATIONS OF H2O MICROWAVE LINE BROADENING IN COLLISIONS WITH HE ATOMS - SENSITIVITY TO POTENTIAL-ENERGY SURFACES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RAMAN-Q-BRANCH; CO-HE; EXCITATION; SPECTROSCOPY; LINEWIDTHS; TRANSITION; SCATTERING; WATER; D2 AB Broadening parameters for three microwave lines of water at 22.2, 183.3, and 380.2 GHz, in a bath of helium atoms, are calculated using accurate molecular scattering S matrices obtained from two theoretical potentials presented by Palma et al., J. Chem. Phys. 89, 1401 (1988). For the 22 GHz line results are in substantial agreement with values presented in that work, indicating the accuracy of approximate methods used there. The present work improves the potential energy surfaces, computed from perturbation theory (MP4) and variational interacting correlated fragments (ICF1) wave functions, by correcting them for basis set superposition error (BSSE), and recomputes the line broadening using a different procedure for fitting computed energy points. In addition, the entire set of calculations are repeated with a quite different basis set for orbital expansion to establish the reliability of the potential energy surface. We show that adjustments for superposition error are essential, and that broadening cross sections computed from the new surfaces are changed 10%-30% from the old, significantly improving agreement with experiment. The MP4 BSSE adjusted surface appears to be the most accurate, giving room temperature broadenings of 8.9, 11.8, and 10.0 angstrom-2 compared with experimental determinations of 12.2 +/- 1.2, 11.9, and 11.2 angstrom-2 for the 22, 183, and 380 GHz lines, respectively. Thus, computed line to line variation is larger than observed. The ICF1 BSSE adjusted results for pressure broadening cross section parallel those from the MP4 BSSE calculations but are about 10% smaller. We believe our computed results are stable with respect to basis set for orbital expansion and that the scattering calculations are accurate. Any theoretical inadequacy has been pinpointed to too few points on the potential energy surface resulting in an inadequate description of the angle dependence. It is not clear whether the present discrepancy between computation and experiment stems from this or from errors in the experimental values, although we show some indication that additional information on the surface might decrease the computed broadenings, worsening agreement with experiment. We believe our computed results are stable with respect to basis set for orbital expansion and that the scattering calculations are accurate. Any theoretical inadequacy has been pinpointed to too few points on the potential energy surface resulting in an inadequate description of the angle dependence. It is not clear whether the present discrepancy between computation and experiment stems from this or from errors in the experimental values, although we show some indication that additional information on the surface might decrease the computed broadenings, worsening agreement with experiment. C1 MOLEC RES INST, PALO ALTO, CA 94304 USA. IBM CORP, ALMADEN RES CTR, SAN JOSE, CA 95120 USA. RP NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, GREENBELT, MD 20771 USA. FU NINDS NIH HHS [NSG 7105] NR 23 TC 44 Z9 44 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 15 PY 1991 VL 94 IS 2 BP 1346 EP 1359 DI 10.1063/1.459992 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EU592 UT WOS:A1991EU59200061 PM 11538204 ER PT J AU FU, LL GLAZMAN, R AF FU, LL GLAZMAN, R TI THE EFFECT OF THE DEGREE OF WAVE DEVELOPMENT ON THE SEA STATE BIAS IN RADAR ALTIMETRY MEASUREMENT SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID NONLINEAR RANDOM SEA; JOINT DISTRIBUTION; SURFACE; GEOMETRY; SLOPES AB The effect of the degree of wave development on the sea state bias (SSB) in Geosat altimeter height measurement is evaluated. Theoretical considerations suggest that the altimetric SSB is generally not a linear function of significant wave height but depends also on other factors of wave development. Of particular interest is its dependence on wave age, defined as the ratio of the phase speed of the dominant ocean waves to ocean wind speed. We estimate wave age rather crudely, on the basis of the significant wave height (H1/3) and wind speed measured by the altimeter. Under general conditions when the sea is not in equilibrium with the wind, this estimate may not correspond to the wave age in a strict sense and hence is called "pseudo wave age" in this paper. Nevertheless, the pseudo wave age is a rough indicator for the degree of wave development. The general trend in the dependence of the SSB on pseudo wave age, as found by analyzing 2.7 years' worth of Geosat data, agrees well with the theoretical prediction: for a given H1/3, the SSB decreases as the degree of the wave development (measured by the pseudo wave age) increases. This empirical trend is modeled as SSB = A (xi/xi-m) (M)H1/3, where xi and xi-m are the pseudo wave age and its average value, respectively; A = 0.013 +/- 0.005, and M = -0.88 +/- 0.37. Statistically, this model performs slightly better than a standard model (i.e., SSB = beta-H1/3 with beta being a constant). In terms of the global rms error the improvement is by 1.6 cm. However, because the degree of wave development varies with the season and geographical location, this small improvement could become important for more accurate altimetric missions in the future when the centimetric, basin-scale signals are the focus of the study. RP FU, LL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 25 TC 49 Z9 51 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 JAN 15 PY 1991 VL 96 IS C1 BP 829 EP 834 DI 10.1029/90JC02319 PG 6 WC Oceanography SC Oceanography GA FD792 UT WOS:A1991FD79200009 ER PT J AU HAHNE, GE AF HAHNE, GE TI TRANSITION OPERATORS IN ACOUSTIC-WAVE DIFFRACTION THEORY .1. GENERAL-THEORY SO PHYSICAL REVIEW A LA English DT Article ID ABSORBING BOUNDARY-CONDITIONS; SURFACE RADIATION CONDITION; ARTIFICIAL BOUNDARY; EQUATIONS; SCATTERING; CYLINDERS AB The objective of this paper is the establishment of a formal theory of the scattering of time-harmonic acoustic scalar waves from impenetrable, immobile obstacles; the time-independent formal scattering theory of nonrelativistic quantum mechanics, in particular the theory of the complete Green's function and the transition (T) operator, provides the model. The quantum-mechanical approach is modified to allow the treatment of acoustic-wave scattering with imposed boundary conditions of impedance type on the surface partial-OMEGA of an impenetrable obstacle. With K0 as the free-space wave number of the signal, a simplified expression is obtained for the k0-dependent T operator for a general case of homogeneous impedance boundary conditions for the acoustic wave on partial-OMEGA. All the nonelementary operators that enter the expression for the T operator are formally simple, rational algebraic functions of a certain invertible linear operator Z(k)0, which is called the radiation impedance operator, and which maps any sufficiently well-behaved, complex-valued function on partial-OMEGA into another such function on partial-OMEGA. The nonlocal operators Z(k)0 and Z(k)0(-1) are defined only implicitly, in that Z(k)0(-1) is the operator that maps the limiting-value function on partial-OMEGA of an outgoing-wave solution to the scalar Helmholtz equation into the uniquely corresponding limiting-normal-derivative function, and Z(k)0 does the inverse operation. Previous appearances in the literature of these operators, or their analogs for other elliptic, linear partial-differential equation systems, are cited. An analytical study of the dominant singularities of the operators (considered as two-point kernels on a smooth partial-OMEGA), and of their behaviour in the geometrical acoustics limit, is the subject of a second paper [G. E. Hahne, following paper, Phys. Rev. A 43, 990 (1991)]. RP HAHNE, GE (reprint author), NASA,AMES RES CTR,COMPUTAT CHEM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 65 TC 3 Z9 3 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JAN 15 PY 1991 VL 43 IS 2 BP 976 EP 989 DI 10.1103/PhysRevA.43.976 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600038 ER PT J AU HAHNE, GE AF HAHNE, GE TI TRANSITION OPERATORS IN ACOUSTIC-WAVE DIFFRACTION THEORY .2. SHORT-WAVELENGTH BEHAVIOR, DOMINANT SINGULARITIES OF ZK0 AND ZK0(-1) SO PHYSICAL REVIEW A LA English DT Article ID BOUNDARY-CONDITIONS; RADIATION AB This second paper of a series deals with special aspects of transition- (T-) operator theory for diffraction of time-harmonic, acoustic scalar waves from an impenetrable obstacle with surface partial-OMEGA. It was shown in the first paper [G. E. Hahne, preceding paper, Phys. Rev. A 43, 976 (1991)] that the computation of the T operator and complete Green's function for the case of "sound-hard" (Neumann-type) and "sound-soft" (Dirichlet-type) boundary conditions on partial-OMEGA reduces to the determination of the "radiation impedance" operator Z(k)0 and the "radiation admittance" operator Z(k)0(-1), respectively, characteristic of partial-OMEGA at wave number k0. In this paper, the short-wavelength and the long-wavelength behavior of these operators as two-point kernels on a smooth partial-OMEGA are studied for pairs of points that are close together. First, an exact, closed-form expression is obtained for both Z(k)0 and Z(k)0(-1) for partial-OMEGA = a plane, on the basis of which a "tangent-plane" approximation to Z(k)0 and to Z(k)0(-1) for diffraction from a general smooth-surfaced, convex obstacle is proposed. This approximation is shown to lead, by means of the method of stationary phase, to the familiar "physical optics" approximation and to the geometrical acoustics limit for diffraction with Neumann-type and with Dirichlet-type boundary conditions. Second, the dominant singularities in Z(k)0 and in Z(k)0(-1) are obtained for smooth partial-OMEGA, and the results are compared to analogous results for partial-OMEGA as a sphere inferred from the spherical harmonic expansions of the two operators. RP HAHNE, GE (reprint author), NASA,AMES RES CTR,COMPUTAT CHEM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 35 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JAN 15 PY 1991 VL 43 IS 2 BP 990 EP 1001 DI 10.1103/PhysRevA.43.990 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600039 ER PT J AU FIEDLERFERRARI, N NUSSENZVEIG, HM WISCOMBE, WJ AF FIEDLERFERRARI, N NUSSENZVEIG, HM WISCOMBE, WJ TI THEORY OF NEAR-CRITICAL-ANGLE SCATTERING FROM A CURVED INTERFACE SO PHYSICAL REVIEW A LA English DT Article ID BEAM DISPLACEMENT; TOTAL REFLECTION; BUBBLE; APPROXIMATION; DIFFRACTION; ALGORITHM; LIGHT; WATER AB A new type of diffraction effect, different from the standard semiclassical ones (rainbow, glory, forward peak, orbiting), takes place near the critical angle for total reflection at a curved interface between two homogeneous media. A theoretical treatment of this new effect is given for Mie scattering, e.g., light scattering by an air bubble in water; it can readily be extended to more general curved interface problems in a variety of different fields (quantum mechanics, acoustics, seismic waves). The relatively slowly varying Mie diffraction pattern associated with near-critical scattering is obscured by rapid fine-structure oscillations due to interference with unrelated "far-side" contributions. These contributions are evaluated and subtracted from the Mie amplitudes to yield the relevant "near-side" effects. A zero-order transitional complex angular momentum (CAM) approximation to the near-side amplitude is developed. The most important contributions arise from partial and total reflection, represented by two new diffraction integrals, designated Fresnel-Fock and Pearcey-Fock, respectively. The total reflection contribution is strongly affected by tunneling, giving rise to a generalized version of the Goos-Hanchen shift. In terms of short-wavelength asymptotic methodology, in a generalized Huygens-Fresnel-type integral representation, the new diffraction features arise from nonanalyticity of the integrand amplitude function within the range of a saddle point. Also discussed are the WKB approximation, a known physical-optics approximation, and a modified version of this approximation: they are compared with the "exact" near-side Mie amplitude obtained by numerical partial-wave summation, at scatterer size parameters (circumference divided by wavelength) ranging from 1000 to 10 000. It is found that the physical-optics approximations lead to large errors in the near-critical region, whereas the zero-order CAM approximation is in good agreement with the exact solution, accounting for the new diffraction effects in near-critical scattering. C1 PONTIFICIA UNIV CATOLICA CHILE,DEPT FIS,BR-22452 RIO DE JANEIRO,BRAZIL. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP FIEDLERFERRARI, N (reprint author), UNIV SAO PAULO,INST FIS,BR-01498 SAO PAULO,SP,BRAZIL. RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 56 TC 29 Z9 30 U1 2 U2 8 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 JAN 15 PY 1991 VL 43 IS 2 BP 1005 EP 1038 DI 10.1103/PhysRevA.43.1005 PG 34 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600041 ER PT J AU DATLA, RU ROBERTS, JR BHATIA, AK AF DATLA, RU ROBERTS, JR BHATIA, AK TI RELATIVE POPULATIONS OF EXCITED-LEVELS WITHIN THE GROUND CONFIGURATION OF SI-LIKE CU, ZN, GE, AND SE IONS SO PHYSICAL REVIEW A LA English DT Note ID EXCITATION; XVII; LINES; NI AB Populations of 3p2 1D2, 3P1, 3P2 levels in Si-like Cu, Zn, Ge, and Se ions have been deduced from the measurements of absolute intensities of magnetic dipole transitions within the 3s(2)3p2 ground configuration. Observations have been made in the Texas Experimental Tokamak (TEXT). The measured population ratios are compared with theoretical calculations based on the distorted-wave approximation for the electron collisions and a semiclassical approximation for the proton collisions. The observed deviation from the statistical distribution for the excited-level populations within the ground configuration along the silicon isoelectronic sequence is in agreement with theoretical prediction. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP DATLA, RU (reprint author), NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899, USA. NR 11 TC 1 Z9 1 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 JAN 15 PY 1991 VL 43 IS 2 BP 1110 EP 1113 DI 10.1103/PhysRevA.43.1110 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600054 ER PT J AU MASSAROTTI, A AF MASSAROTTI, A TI EVOLUTION OF LIGHT DOMAIN-WALLS INTERACTING WITH DARK MATTER SO PHYSICAL REVIEW D LA English DT Article ID STRINGS AB In this paper we discuss the evolution of domain walls generated in the early Universe considering, unlike the previous studies, an interaction between the walls and a major gaseous component of the dark matter. It is assumed that the walls can reflect the particles elastically and with a reflection coefficient of unity. We discuss a toy Lagrangian that could give rise to such a phenomenon. In the simple model studied we obtain highly nonrelativistic and slowly varying speeds for the domain walls [approximately 10(-2)(1+z)-1] and negligible distortions of the microwave background. In addition, these topological defects may provide a mechanism of forming the large-scale structure of the Universe, by creating fluctuations in the dark matter delta-rho/rho-approximately 1 on a scale comparable to the distance the walls move from the formation (in our model this distance could be even tens of Mpc). The characteristic scale of the wall separation can be easily chosen to be of the order of 100 Mpc instead of being restricted to the horizon scale, as usually obtained. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP MASSAROTTI, A (reprint author), UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637, USA. NR 14 TC 13 Z9 13 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 1991 VL 43 IS 2 BP 346 EP 352 DI 10.1103/PhysRevD.43.346 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ET217 UT WOS:A1991ET21700009 ER PT J AU GREGORY, R AF GREGORY, R TI EFFECTIVE ACTIONS FOR BOSONIC TOPOLOGICAL DEFECTS SO PHYSICAL REVIEW D LA English DT Article ID STRINGS AB We consider a gauge field theory which admits p-dimensional topological defects, expanding the equations of motion in powers of the defect thickness. In this way we derive an effective action and effective equation of motion for the defect in terms of the coordinates of the p-dimensional world surface defined by the history of the core of the defect. RP GREGORY, R (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 12 TC 38 Z9 38 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 1991 VL 43 IS 2 BP 520 EP 525 DI 10.1103/PhysRevD.43.520 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ET217 UT WOS:A1991ET21700027 ER PT J AU ANDERSSON, BG WANNIER, PG MORRIS, M AF ANDERSSON, BG WANNIER, PG MORRIS, M TI WARM NEUTRAL HALOS AROUND MOLECULAR CLOUDS .3. INTERPRETATION OF H-I AND CO-J = 1-0 DATA SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERSTELLAR MOLECULES; RADIO SOURCES 21-CM RADIATION ID INTER-STELLAR CLOUDS; STEADY-STATE MODELS; CARBON-MONOXIDE; INTERSTELLAR GAS; DARK CLOUDS; RADIATION TRANSPORT; PHYSICAL CONDITIONS; HYDROSTATIC MODELS; HYDROGEN; PHOTODISSOCIATION AB A study is presented of the physical characteristics of the transition region separating the molecular and the atomic medium in interstellar clouds, based on H I 21 cm and CO j = 1-0 data. We find strong evidence for general heating of the surface layers of molecular clouds, and for the existence of large, heated neutral atomic halos around the molecular clouds. The heating of the molecular cloud surface is manifested through the general existence of limb brightening in the CO emission, with a characteristic depth of 1.7 pc. dependent on the Galactic latitude. He heated H I halos have a characteristic depth of 4.7 pc and a maximal extent of about 10 pc. C1 GOTHENBURG UNIV,S-41124 GOTHENBURG,SWEDEN. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. RP ANDERSSON, BG (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 56 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 1991 VL 366 IS 2 BP 464 EP 473 DI 10.1086/169581 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP662 UT WOS:A1991EP66200013 ER PT J AU CROTTS, APS KUNKEL, WE AF CROTTS, APS KUNKEL, WE TI USING SN-1987A LIGHT ECHOES TO DETERMINE MASS-LOSS FROM THE PROGENITOR SO ASTROPHYSICAL JOURNAL LA English DT Article ID SUPERNOVA 1987-A; CLOUD AB We have monitored the many light echoes seen near SN 1987A to find how the SN progenitor influenced its preexplosion environment. There is a smooth distribution of light dimming from radii 3"-10", consistent with an echo from the mass lost at a constant rate from a red supergiant atmosphere. This flow terminates in two shocks (the smaller, bow-shaped echo and the oval-shaped echo described herein), the larger containing 12 times the mass of the flow. The total mass in all these structures (assuming spherical symmetry) is 4.5 M., assuming Mgas/Mdust = 1000 and a grain model favored by our data (50 nm radius graphite spheres). The progenitor needed almost-equal-to 10(6) yr to create these structures, assuming a constant mass loss at velocity 15 km s-1. The dust in this region is small-grained (mostly radii < 70 nm) and isotropically scattering (g < 0.2). Interaction between the progenitor blue supergiant and red supergiant winds is complex, but are likely contained within a 1.5 pc diameter, roughly spherical structure. We have also discovered a fourth star in the Sanduleak -69-degrees-202 system, 2" southwest of the SN (P. A. = 243-degrees). C1 NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,GREENBELT,MD 20771. CARNEGIE INST WASHINGTON OBSERV,WASHINGTON,DC. NR 29 TC 35 Z9 35 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 1991 VL 366 IS 2 BP L73 EP & DI 10.1086/185912 PN 2 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP663 UT WOS:A1991EP66300006 ER PT J AU HILL, CT STEINHARDT, PJ TURNER, MS AF HILL, CT STEINHARDT, PJ TURNER, MS TI COHERENT PECULIAR VELOCITIES AND PERIODIC REDSHIFTS SO ASTROPHYSICAL JOURNAL LA English DT Article ID GALAXY FORMATION; UNIVERSE; CLUSTERS; EXPLOSIONS AB A coherent, sinusoidal peculiar velocity field of amplitude delta-upsilon/c congruent-to 3 x 10(-3) and wavelength lambda congruent-to 128h-1 Mpc could explain the apparent redshift periodicity seen in the recent pencil-beam survey of Broadhurst et al. Such a peculiar velocity field could arise if the power spectrum of density perturbations has a strong feature at about this wavelength (e. g., a bump). This explanation has additional predictions: the phase, period, and strength of the periodicity should vary in different directions; the strength of the periodicity should decrease at higher redshifts; and there should be more "thin" structures perpendicular to the line of sight than parallel to it. C1 UNIV PENN,DAVID RITTENHOUSE LAB,DEPT PHYS,PHILADELPHIA,PA 19104. FERMI NATL ACCELERATOR LAB,NASA,CTR ASTROPHYS,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP HILL, CT (reprint author), FERMI NATL ACCELERATOR LAB,DEPT THEORET PHYS,MS 106,POB 500,BATAVIA,IL 60510, USA. NR 28 TC 13 Z9 13 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 1991 VL 366 IS 2 BP L57 EP L60 DI 10.1086/185908 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP663 UT WOS:A1991EP66300002 ER PT J AU LANDSMAN, W SIMON, T AF LANDSMAN, W SIMON, T TI STELLAR LYMAN-ALPHA-EMISSION AND THE LOCAL INTERSTELLAR-MEDIUM SO ASTROPHYSICAL JOURNAL LA English DT Article ID F-STARS; IUE AB We report on a search of IUE spectra for the presence of Ly-alpha emission in late-type stars. We have found Ly-alpha emission in the spectra of 222 stars, and have measured upper limits toward 39 additional stars. The numerous Ly-alpha detections confirm that the local interstellar medium is relatively free of neutral hydrogen and suggest that observations below 912 angstrom should be feasible toward a large number of stars in the solar neighborhood. Our results provide the first survey of the behavior of the Ly-alpha emission line across most of the cool half of the H-R diagram. The normalized Ly-alpha emission flux is strongest in the chromospherically active RS CVn stars and in the dMe stars. The range of normalized Ly-alpha flux values is much smaller among F-type stars than in stars of later spectral type. There appears to be a dropoff, but not an absence, in the Ly-alpha flux levels of stars at B-V < 0.30 mag. We have used our Ly-alpha flux measurements to search for evidence of possible high column density (> 10(19) cm-2) clouds in the local interstellar medium. The cloud previously identified toward alpha-Oph (l = 36-degrees, b = +23-degrees, d = 18 pc) may be seen in the reduced Ly-alpha flux observed toward beta-Oph. An additional high column density region within 20 pc is also suggested by the reduced Ly-alpha flux observed toward four stars in the direction l = 230-degrees, b = -48-degrees. C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. RP LANDSMAN, W (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ST SYST CORP,GREENBELT,MD 20771, USA. NR 21 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 JAN 10 PY 1991 VL 366 IS 2 BP L79 EP L82 DI 10.1086/185913 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP663 UT WOS:A1991EP66300007 ER PT J AU BLACK, MT ZUBER, MT MCADOO, DC AF BLACK, MT ZUBER, MT MCADOO, DC TI COMPARISON OF OBSERVED AND PREDICTED GRAVITY PROFILES OVER APHRODITE TERRA, VENUS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS LA English DT Article ID GEOID ANOMALIES; HEAT-FLOW; TOPOGRAPHY; MODEL; OCEAN; CONVECTION; BATHYMETRY; TECTONICS; EVOLUTION; FIELD AB We compare observed Pioneer Venus orbiter (PVO) gravity profiles over Aphrodite Terra to profiles predicted from models of thermal isostasy, mantle convection, and Airy compensation. Similar approaches are used in order to investigate how well the models can be distinguished with the PVO data. Topography profiles across Aphrodite are compared to model spreading ridge profiles in order to further assess this model. Airy compensation depths and convection layer thicknesses are greater under eastern Aphrodite than western Aphrodite. Compensation depths in the east are greater than most estimates of lithospheric thickness, suggesting that this part of the ridge is dynamically supported. In parts of western Aphrodite, the spreading ridge model gravity provides a better fit to the data than either Airy compensation or mantle convection. Best-fit spreading rates are between 0.3 and 1.6 cm/yr. Airy compensation and mantle convection cannot be distinguished in most places using only PVO data. C1 NOAA,NATL OCEAN SERV,NATL GEODET SURVEY,CHARTING & GEODET SERV,ROCKVILLE,MD 20852. NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771. RP BLACK, MT (reprint author), UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742, USA. RI McAdoo, Dave/F-5612-2010 OI McAdoo, Dave/0000-0002-7533-5564 NR 41 TC 11 Z9 12 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-SOLID PD JAN 10 PY 1991 VL 96 IS B1 BP 301 EP 315 DI 10.1029/90JB01853 PG 15 WC Geosciences, Multidisciplinary SC Geology GA ER677 UT WOS:A1991ER67700001 ER PT J AU ABRAMS, M ABBOTT, E KAHLE, A AF ABRAMS, M ABBOTT, E KAHLE, A TI COMBINED USE OF VISIBLE, REFLECTED INFRARED, AND THERMAL INFRARED IMAGES FOR MAPPING HAWAIIAN LAVA FLOWS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS LA English DT Article ID ROCK COATINGS AB The weathering of Hawaiian basalts is accompanied by chemical and physical changes of the surfaces. These changes have been mapped using remote sensing data from the visible and reflected infrared and thermal infrared wavelength regions. They are related to the physical breakdown of surface chill coats, the development and erosion of silica coatings, the oxidation of mafic minerals, and the development of vegetation cover. These effects show systematic behavior with age and can be mapped using the image data and related to relative ages of pahoehoe and aa flows. The thermal data are sensitive to silica rind development and fine structure of the scene; the reflectance data show the degree of oxidation and differentiate vegetation from aa and cinders. Together, data from the two wavelength regions show more than either separately. The combined data potentially provide a powerful tool for mapping basalt flows in arid to semiarid volcanic environments. RP ABRAMS, M (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 14 TC 40 Z9 43 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOLID PD JAN 10 PY 1991 VL 96 IS B1 BP 475 EP 484 DI 10.1029/90JB01392 PG 10 WC Geosciences, Multidisciplinary SC Geology GA ER677 UT WOS:A1991ER67700013 ER PT J AU KIM, JH LARSSON, A LEE, LP AF KIM, JH LARSSON, A LEE, LP TI PSEUDOMORPHIC INYGA1-YAS/GAAS/ALXGA1-XAS SINGLE QUANTUM-WELL SURFACE-EMITTING LASERS WITH INTEGRATED 45-DEGREES BEAM DEFLECTORS SO APPLIED PHYSICS LETTERS LA English DT Article ID LASING CHARACTERISTICS; MIRRORS; ARRAYS; DIODE AB We report on the first demonstration of pseudomorphic InGaAs single quantum well surface-emitting lasers (SELs), with etched vertical mirrors and integrated 45-degrees beam deflectors fabricated by ion beam etching. 100-mu-m-wide broad-area SELs exhibited a threshold current of 320 mA, a total power of 126 mW, and a total external differential quantum efficiency of 0.09 W/A for a 500-mu-m-long cavity. The perpendicular far-field pattern of broad-area SELs showed a full width at half maximum of approximately 20-degrees. The lasers with various types of cavities fabricated from the same wafer were compared. Broad-area edge-emitting lasers had a threshold current of 200 mA, a total power of 700 mW, and a total external differential quantum efficiency of 0.52 W/A. C1 TRW CO INC,DIV APPL TECHNOL SPACE & TECHNOL GRP,REDONDO BEACH,CA 90278. RP KIM, JH (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. RI Larsson, Anders/P-7275-2015 OI Larsson, Anders/0000-0002-0912-7695 NR 21 TC 10 Z9 10 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 7 PY 1991 VL 58 IS 1 BP 7 EP 9 DI 10.1063/1.104451 PG 3 WC Physics, Applied SC Physics GA ER077 UT WOS:A1991ER07700003 ER PT J AU KENNY, TW WALTMAN, SB REYNOLDS, JK KAISER, WJ AF KENNY, TW WALTMAN, SB REYNOLDS, JK KAISER, WJ TI MICROMACHINED SILICON TUNNEL SENSOR FOR MOTION DETECTION SO APPLIED PHYSICS LETTERS LA English DT Article ID MICROMECHANICAL CAPACITIVE ACCELEROMETER; INERTIAL-MASS SUSPENSION; MICROSCOPY; NOISE AB We have used the extreme sensitivity of electron tunneling to variations in electrode separation to construct a novel, compact displacement transducer. Electrostatic forces are used to control the separation between the tunneling electrodes, thereby eliminating the need for piezoelectric actuators. The entire structure is composed of micromachined silicon single crystals, including a folded cantilever spring and a tip. Measurements of displacement sensitivity and noise are reported. This device offers a substantial improvement over conventional technology for applications which require compact, highly sensitive transducers. RP KENNY, TW (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 20 TC 70 Z9 72 U1 0 U2 16 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 7 PY 1991 VL 58 IS 1 BP 100 EP 102 DI 10.1063/1.104432 PG 3 WC Physics, Applied SC Physics GA ER077 UT WOS:A1991ER07700035 ER PT J AU TURNER, MS WILCZEK, F AF TURNER, MS WILCZEK, F TI INFLATIONARY AXION COSMOLOGY SO PHYSICAL REVIEW LETTERS LA English DT Article ID ISOTHERMAL DENSITY PERTURBATIONS; UNIVERSE THERMAL PRODUCTION; SO-INVISIBLE AXIONS; LOCAL MASS DENSITY; COSMIC AXIONS; OSCILLATIONS; RADIATION; LIMITS AB If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10(-6) eV. This bound can be evaded if the Universe underwent inflation after PQ-symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, theta-1 less-than-or-similar-to [m(a)/(10(-6) eV)]0.59. We show consideration of fluctuations induced during inflation severely constrains the latter alternative. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS & ASTRON,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTROPHYS,CHICAGO,IL 60637. PRINCETON UNIV,INST ADV STUDY,PRINCETON,NJ 08540. RP TURNER, MS (reprint author), FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,NASA,BATAVIA,IL 60510, USA. NR 39 TC 107 Z9 107 U1 0 U2 4 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 7 PY 1991 VL 66 IS 1 BP 5 EP 8 DI 10.1103/PhysRevLett.66.5 PG 4 WC Physics, Multidisciplinary SC Physics GA ER074 UT WOS:A1991ER07400002 ER PT J AU ULABY, F HADDAD, G KUKKONEN, C AF ULABY, F HADDAD, G KUKKONEN, C TI SPECIAL ISSUE ON TERAHERTZ TECHNOLOGY - FOREWORD SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Editorial Material RP ULABY, F (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,ANN ARBOR,MI 48109, USA. NR 0 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 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD JAN 5 PY 1991 VL 4 IS 1 BP 1 EP 1 DI 10.1002/mop.4650040102 PG 1 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA EW494 UT WOS:A1991EW49400001 ER PT J AU WATERS, JW AF WATERS, JW TI SUBMILLIMETER HETERODYNE REMOTE-SENSING OF UPPER ATMOSPHERIC GASES SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL SYMP ON SPACE TERAHERTZ TECHNOLOGY CY MAR 05-06, 1990 CL UNIV MICHIGAN, ANN ARBOR, MI SP NASA, SPACE ENGN RES CTR HO UNIV MICHIGAN DE SUBMILLIMETER; STRATOSPHERE; OZONE; REMOTE SENSING AB Technology is now becoming available to develop submillimeter-wavelength heterodyne radiometric experiments for remote sensing the upper atmosphere from space. Such experiments can provide many essential measurements for assessing and critically monitoring the depletion of stratospheric ozone by pollution from industrial products. A millimeter-wavelength experiment for this purpose is now ready for launch on the NASA Upper Atmosphere Research Satellite (UARS). An enhanced version of the UARS experiment, which operates at submillimeter wavelengths, is under investigation for the future NASA Earth Observing System. RP WATERS, JW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 7 Z9 7 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD JAN 5 PY 1991 VL 4 IS 1 BP 2 EP 6 DI 10.1002/mop.4650040103 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA EW494 UT WOS:A1991EW49400002 ER PT J AU GEARHART, SS LING, CC REBEIZ, GM AF GEARHART, SS LING, CC REBEIZ, GM TI INTEGRATED 222-GHZ CORNER-REFLECTOR ANTENNAS SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL SYMP ON SPACE TERAHERTZ TECHNOLOGY CY MAR 05-06, 1990 CL UNIV MICHIGAN, ANN ARBOR, MI SP NASA, SPACE ENGN RES CTR HO UNIV MICHIGAN DE INTEGRATED CORNER-CUBE ANTENNAS; SUBMILLIMETER-WAVE RECEIVERS; IMAGING ARRAYS; DIELECTRIC MEMBRANES AB A high-gain monolithic millimeter-wave antenna has been designed, fabricated and tested at 222 GHz. The structure consists of a traveling-wave antenna integrated on a 1.2-mu-m dielectric membrane and suspended in a longitudinal cavity etched in a silicon wafer. A new traveling-wave antenna design yields a wideband input impedance and a low cross-polarization component in the E- and quasi-H-plane patterns. A directivity of 17.7 dB and a main-beam efficiency of 88.5% are calculated from the 222-GHz pattern measurements. The integrated corner-reflector antenna is well suited for millimeter-and submillimeter-wave imaging applications in large f-number systems. RP GEARHART, SS (reprint author), UNIV MICHIGAN,NASA,CTR SPACE TERAHERTZ TECHNOL,DEPT ELECT ENGN & COMP SCI,ANN ARBOR,MI 48109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD JAN 5 PY 1991 VL 4 IS 1 BP 12 EP 15 DI 10.1002/mop.4650040106 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA EW494 UT WOS:A1991EW49400005 ER PT J AU SCHOEBERL, MR HARTMANN, DL AF SCHOEBERL, MR HARTMANN, DL TI THE DYNAMICS OF THE STRATOSPHERIC POLAR VORTEX AND ITS RELATION TO SPRINGTIME OZONE DEPLETIONS SO SCIENCE LA English DT Article ID ANTARCTIC OZONE; POTENTIAL VORTICITY; INTERANNUAL VARIABILITY; WINTER STRATOSPHERE; TRANSPORT; EVOLUTION; SEPTEMBER; WARMINGS; MODEL; HOLE AB Dramatic springtime depletions of ozone in polar regions require that polar stratospheric air has a high degree of dynamical isolation and extremely cold temperatures necessary for the formation of polar stratospheric clouds. Both of these conditions are produced within the stratospheric winter polar vortex. Recent aircraft missions have provided new information about the structure of polar vortices during winter and their relation to polar ozone depletions. The aircraft data show that gradients of potential vorticity and the concentration of conservative trace species are large at the transition from mid-latitude to polar air. The presence of such sharp gradients at the boundary of polar air implies that the inward mixing of heat and constituents is strongly inhibited and that the perturbed polar stratospheric chemistry associated with the ozone hole is isolated from the rest of the stratosphere until the vortex breaks up in late spring. The overall size of the polar vortex thus limits the maximum areal coverage of the annual polar ozone depletions. Because it appears that this limit has not been reached for the Antarctic depletions, the possibility of future increases in the size of the Antarctic ozone hole is left open. In the Northern Hemisphere, the smaller vortex and the more restricted region of cold temperatures suggest that this region has a smaller theoretical maximum for column ozone depletion, about 40 percent of the currently observed change in the Antarctic ozone column in spring. C1 UNIV WASHINGTON,DEPT ATMOSPHER SCI,SEATTLE,WA 98195. RP SCHOEBERL, MR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 62 TC 181 Z9 182 U1 2 U2 21 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 4 PY 1991 VL 251 IS 4989 BP 46 EP 52 DI 10.1126/science.251.4989.46 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EQ603 UT WOS:A1991EQ60300024 PM 17778602 ER PT J AU NUTH, J AF NUTH, J TI SOLAR-SYSTEM - SMALL GRAINS OF TRUTH SO NATURE LA English DT Editorial Material RP NUTH, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 3 PY 1991 VL 349 IS 6304 BP 18 EP 19 DI 10.1038/349018a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EQ601 UT WOS:A1991EQ60100023 ER PT J AU FLASAR, FM AF FLASAR, FM TI SATURN - AT THE EYE OF THE STORM SO NATURE LA English DT Editorial Material RP FLASAR, FM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI Flasar, F Michael/C-8509-2012 NR 2 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 3 PY 1991 VL 349 IS 6304 BP 21 EP 21 DI 10.1038/349021a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EQ601 UT WOS:A1991EQ60100028 ER PT J AU HARRIS, JM DUST, JM MCGILL, RA HARRIS, PA EDGELL, MJ SEDAGHATHERATI, RM KARR, LJ DONNELLY, DL AF HARRIS, JM DUST, JM MCGILL, RA HARRIS, PA EDGELL, MJ SEDAGHATHERATI, RM KARR, LJ DONNELLY, DL TI NEW POLYETHYLENE GLYCOLS FOR BIOMEDICAL APPLICATIONS SO ACS SYMPOSIUM SERIES LA English DT Article ID POLY(ETHYLENE GLYCOL); IMMOBILIZATION; ATTACHMENT; CONJUGATE AB Polyethylene glycols (PEGs) are neutral, water soluble polymers possessing an impressive array of biomedical and biotechnical applications. In the current article we describe work in our laboratories on synthesis and characterization of new PEG aldehydes. These novel PEGs have the advantages of selective reactivity toward amino groups and stability in an aqueous environment. The reactivity of two new aldehydes toward simple amines, proteins, and aminated surfaces is described. In addition we have examined some recent chemistry on amination of glass surfaces by silanization with different silanes under a variety of conditions. This work shows that monoethoxyaminosilanes, while giving relatively low percentages of nitrogen on the surface, yield more reactive amino groups on the surface than do triethoxy- and diethoxy-silanes. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. RP UNIV ALABAMA, DEPT CHEM, HUNTSVILLE, AL 35899 USA. NR 35 TC 17 Z9 17 U1 2 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 467 BP 418 EP 429 PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA GC601 UT WOS:A1991GC60100028 ER PT J AU STUCKY, GD MARDER, SR SOHN, JE AF STUCKY, GD MARDER, SR SOHN, JE TI LINEAR AND NONLINEAR POLARIZABILITY - A PRIMER SO ACS SYMPOSIUM SERIES LA English DT Article AB In this introductory chapter the concepts of linear and nonlinear polarization are discussed. Both classical and quantum mechanical descriptions of polarizability based on potential surfaces and the "sum over states" formalism are outlined. In addition, it is shown how nonlinear polarization of electrons gives rise to a variety of useful nonlinear optical effects. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. AT&T BELL LABS, PRINCETON, NJ 08540 USA. RP STUCKY, GD (reprint author), UNIV CALIF SANTA BARBARA, SANTA BARBARA, CA 93106 USA. NR 16 TC 6 Z9 6 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 455 BP 2 EP 30 PG 29 WC Chemistry, Multidisciplinary SC Chemistry GA FM047 UT WOS:A1991FM04700001 ER PT J AU PERRY, JW AF PERRY, JW TI NONLINEAR OPTICAL-PROPERTIES OF MOLECULES AND MATERIALS SO ACS SYMPOSIUM SERIES LA English DT Article ID 3RD HARMONIC-GENERATION; SUSCEPTIBILITY DETERMINATION; 3RD-HARMONIC GENERATION; LIQUIDS AB This paper is a tutorial overview of the techniques used to characterize the nonlinear optical properties of bulk materials and molecules. Methods that are commonly used for characterization of second- and third-order nonlinear optical properties are covered. Several techniques are described briefly and then followed by a more detailed discussion of the determination of molecular hyperpolarizabilities using third harmonic generation. RP PERRY, JW (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 32 TC 10 Z9 10 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 455 BP 67 EP 88 PG 22 WC Chemistry, Multidisciplinary SC Chemistry GA FM047 UT WOS:A1991FM04700004 ER PT J AU BERATAN, DN AF BERATAN, DN TI ELECTRONIC HYPERPOLARIZABILITY AND CHEMICAL-STRUCTURE SO ACS SYMPOSIUM SERIES LA English DT Article ID NONLINEAR OPTICAL-PROPERTIES; CONJUGATED ORGANIC POLYMERS; CHAINS; SUSCEPTIBILITIES AB The chemical structure dependence of electronic hyperpolarizability is discussed. Strategies for developing structure-function relationships for nonlinear optical chromophores are presented. Some of the important parameters in these relationships, including the relative ionization potential of reduced donor and acceptor and the chain length, are discussed. The correspondence between molecular orbital and classical anharmonic oscillator models for nonlinear polarizability is described. RP BERATAN, DN (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RI Beratan, David/C-5098-2011 NR 39 TC 20 Z9 20 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 455 BP 89 EP 102 PG 14 WC Chemistry, Multidisciplinary SC Chemistry GA FM047 UT WOS:A1991FM04700005 ER PT J AU MARDER, SR TIEMANN, BG PERRY, JW CHENG, LT TAM, W SCHAEFER, WP MARSH, RE AF MARDER, SR TIEMANN, BG PERRY, JW CHENG, LT TAM, W SCHAEFER, WP MARSH, RE TI ORGANIC AND ORGANOMETALLIC COMPOUNDS - 2ND-ORDER MOLECULAR AND MACROSCOPIC OPTICAL NONLINEARITIES SO ACS SYMPOSIUM SERIES LA English DT Article ID 2ND HARMONIC-GENERATION; 2ND-HARMONIC GENERATION; INCLUSION COMPLEXES; DIPOLE-MOMENT; HYPERPOLARIZABILITIES; CRYSTALS AB Organic and organometallic stilbazolium cations can be crystallized with various counterions; some of the resulting salts exhibit large SHG powder efficiencies. Approximately linear stilbazolium cations have a greater tendency to crystallize in noncentrosymmetric space groups than do cations with substantial geometric asymmetry. The nonresonant quadratic molecular hyperpolarizabilities of several ferrocene and ruthenocene derivatives were studied by DC electric-field-induced second-harmonic generation (EFISH) experiments using fundamental radiation at 1.91-mu-m. Hyperpolarizabilities approaching that of 4-dimethylamino 4'-nitro-stilbene (DANS) were observed indicating that the ferrocene moiety can act as an effective donor. EFISH measurements indicate that indoaniline dyes with very polarizable pi systems have large molecular hyperpolarizabilities (beta), in one case approaching three times that of DANS. C1 DUPONT CO, DEPT CENT RES & DEV, WILMINGTON, DE 19880 USA. CALTECH, DIV CHEM & CHEM ENGN, PASADENA, CA 91125 USA. RP MARDER, SR (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 37 TC 16 Z9 16 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 455 BP 187 EP 199 PG 13 WC Chemistry, Multidisciplinary SC Chemistry GA FM047 UT WOS:A1991FM04700011 ER PT J AU GRUBBS, RH GORMAN, CB GINSBURG, EJ PERRY, JW MARDER, SR AF GRUBBS, RH GORMAN, CB GINSBURG, EJ PERRY, JW MARDER, SR TI NEW POLYMERIC MATERIALS WITH CUBIC OPTICAL NONLINEARITIES DERIVED FROM RING-OPENING METATHESIS POLYMERIZATION SO ACS SYMPOSIUM SERIES LA English DT Article ID CIS-TRANS ISOMERIZATION; CONJUGATED POLYMERS; OLEFIN METATHESIS; POLYACETYLENE; ROUTE AB Partially substituted derivatives of polyacetylene are synthesized via the ring-opening metathesis polymerization (ROMP) of cyclooctatetraene (COT) and its derivatives. Certain poly-COT derivatives afford soluble, highly conjugated polyacetylenes. These materials exhibit large third-order optical nonlinearities and low scattering losses. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP GRUBBS, RH (reprint author), CALTECH, DIV CHEM & CHEM ENGN, ARNOLD & MABEL BECKMAN CHEM SYNTHESIS LAB, PASADENA, CA 91125 USA. RI Gorman, Christopher/A-3463-2008; grubbs, robert/D-4293-2009; Perry, Joseph/B-7191-2011 OI Gorman, Christopher/0000-0001-7367-2965; grubbs, robert/0000-0002-0057-7817; Perry, Joseph/0000-0003-1101-7337 NR 41 TC 8 Z9 8 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0097-6156 J9 ACS SYM SER JI ACS Symp. Ser. PY 1991 VL 455 BP 672 EP 682 PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA FM047 UT WOS:A1991FM04700045 ER PT J AU YUEN, JH RESCH, GM STELZRIED, CT AF YUEN, JH RESCH, GM STELZRIED, CT TI TELECOMMUNICATIONS TECHNOLOGY DEVELOPMENT FOR THE DEEP SPACE NETWORK SO ACTA ASTRONAUTICA LA English DT Article AB The Deep Space Network (DSN) is sponsored by the National Aeronautics and Space Administration (NASA) Office of Space Operations, and provides communications and navigation support for NASA's deep space missions, lunar and high Earth orbiters. It has continuously evolving facilities whose instruments are also used for planetary radar, radio science, and radio astronomy. Over the past 30 years, the communications and navigation performance has increased many orders of magnitude. The receiving sensitivity and radio metric data accuracy are near the present-day achievable limits and are upgraded as mission needs, technology developments, and resources direct. Despite the technological evolution that is continuously underway, operations are highly reliable and versatile for the various mission requirements. Advanced technologies are being aggressively developed to improve future DSN capabilities. These advanced technologies, will be implemented into the DSN and will provide greater freedom to trade-off communications and navigational capability against mass and power on a spacecraft. The major areas that are currently being developed include Ka-Band (32 GHz) technology, beam waveguide antennas, low noise amplifiers, coding, navigation techniques, high power transmitters, and optical technology. This paper discusses the technology that is currently being developed for the DSN and its expected dividends during the mid-1990s and later. RP YUEN, JH (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 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 JAN PY 1991 VL 25 IS 1 BP 51 EP 60 DI 10.1016/0094-5765(91)90006-Q PG 10 WC Engineering, Aerospace SC Engineering GA FD549 UT WOS:A1991FD54900005 ER PT J AU LUM, H HEER, E AF LUM, H HEER, E TI COST-EFFECTIVE IMPLEMENTATION OF INTELLIGENT SYSTEMS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB Significant advances have occurred during the last decade in knowledge-based engineering research and knowledge-based system (KBS) demonstrations and evaluations using integrated intelligent system technologies. Performance and simulation data obtained to date in real-time operational environments suggest that cost-effective utilization of intelligent system technologies can be realized. In this paper the rationale and potential benefits for typical examples of application projects that demonstrate an increase in productivity through the use of intelligent system technologies are discussed. These demonstration projects have provided an insight into additional technology needs and cultural barriers which are currently impeding the transition of the technology into operational environments. Proposed methods which address technology evolution and implementation are also discussed. RP LUM, H (reprint author), NASA,AMES RES CTR,DIV INFORMAT SCI,MOFFETT FIELD,CA 94035, USA. NR 0 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 24 BP 23 EP 31 PG 9 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300004 ER PT J AU MCCAIN, HG ANDARY, JF HEWITT, DR HALEY, DC AF MCCAIN, HG ANDARY, JF HEWITT, DR HALEY, DC TI THE SPACE STATION FREEDOM FLIGHT TELEROBOTIC SERVICER - THE DESIGN AND EVOLUTION OF A DEXTEROUS SPACE ROBOT SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB The Flight Telerobotic Servicer (FTS) Project at the Goddard Space Flight Center is developing an advanced telerobotic system to assist in and reduce crew extravehicular activity (EVA) for Space Station Freedom (SSF). The FTS will provide a telerobotic capability to the Freedom Station in the early assembly phases of the program and will be employed for assembly, maintenance, and inspection applications throughout the lifetime of the space station. Appropriately configured elements of the FTS will also be employed for robotic manipulation in remote satellite servicing applications and possibly the Lunar/Mars Program. RP MCCAIN, HG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 1 U2 2 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. PY 1991 VL 24 BP 45 EP 54 DI 10.1016/0094-5765(91)90151-T PG 10 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300006 PM 11540062 ER PT J AU GRINER, CS AF GRINER, CS TI STRATEGIC-PLANNING FOR THE INTERNATIONAL SPACE STATION SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB The concept for utilization and operations planning for the International Space Station Freedom was developed in a NASA Space Station Operations Task Force in 1986. Since that time the concept has been further refined to definitize the process and products required to integrate the needs of the international user community with the operational capabilities of the Station in its evolving configuration. The keystone to the process is the development of individual plans by the partners, with the parameters and formats common to the degree that electronic communications techniques can be effectively utilized, while maintaining the proper level and location of configuration control. The integration, evaluation, and verification of the integrated plan, called the Consolidated Operations and Utilization Plan (COUP), is being tested in a multilateral environment to prove out the parameters, interfaces, and process details necessary to produce the first COUP for Space Station in 1991. This paper will describe the concept, process, and the status of the multilateral test case. RP GRINER, CS (reprint author), NASA,OFF SPACE FLIGHT,SPACE STN OPERAT & UTILIZAT,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 1 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. PY 1991 VL 24 BP 55 EP 60 DI 10.1016/0094-5765(91)90152-U PG 6 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300007 ER PT J AU SALOMONSON, VV CHOUDHURY, BJ AF SALOMONSON, VV CHOUDHURY, BJ TI REMOTE-SENSING CONTRIBUTION TO LAND SURFACE HYDROLOGY SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB Over the last decade, the importance of the global hydrological cycle has become increasingly clear in understanding global processes. Furthermore, the utility of spaceborne observations for global studies has been better demonstrated. Optical sensors such as the NOAA AVHRR and the Landsat or SPOT sensors, for example, have been demonstrated to provide land cover information describing the dynamics of vegetation and snow cover over a variety of spatial and temporal scales. Microwave observations from the synthetic aperture radars and passive microwave radiometers such as the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) have been shown to effectively observe snowpack properties, vegetation condition, biomass volume, and condition and indices of soil wetness. The Earth Observing System (EOS) mission plus complementary missions such as ERS-1, the Japanese ERS-1, and the Tropical Rainfall Measuring Mission (TRMM) offer the potential to extend and improve presently available observations from space so more knowledge and understanding of the global hydrological cycle will be obtained. RP SALOMONSON, VV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 3 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. PY 1991 VL 24 BP 121 EP 127 DI 10.1016/0094-5765(91)90159-3 PG 7 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300014 ER PT J AU COHEN, A MINOR, RG LOFTUS, JP AF COHEN, A MINOR, RG LOFTUS, JP TI THE EVOLUTION OF THE SPACE-SHUTTLE SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB As the mission manifest develops in response to the needs of the users, new capabilities are being developed for the Shuttle. Other changes are being introduced in order to provide Assured Shuttle Availability (ASA), that is, safe efficient flight operations into the 21st century. These changes will provide simpler turnaround processing procedures, enhanced subsystem reliability, a reduction in critical failure modes, and enhanced operational flexibility. RP COHEN, A (reprint author), LYNDON B JOHNSON SPACE CTR,HOUSTON,TX, 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. PY 1991 VL 24 BP 129 EP 136 DI 10.1016/0094-5765(91)90160-7 PG 8 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300015 ER PT J AU BANKSTON, CP ATKINS, KL MASTAL, EF MCCONNELL, DG AF BANKSTON, CP ATKINS, KL MASTAL, EF MCCONNELL, DG TI TECHNOLOGY DEVELOPMENT ISSUES IN SPACE NUCLEAR-POWER FOR PLANETARY EXPLORATION SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB Planning for future planetary exploration missions indicates that there are continuing, long range requirements for nuclear power, and in particular radioisotope-based power sources. In meeting these requirements, there is a need for higher efficiency, lower mass systems. We describe here four technology areas currently under development that address these goals: modular RTG, modular RTG with advanced thermoelectric materials, dynamic isotope power system(DIPS), and the Alkali Metal Thermoelectric Converter(AMTEC). The modular RTG is the next generation improvement in RTG performance, where work is now focussed on development of the multicouple converter technology. If advances are also made in thermoelectric materials, the modular RTG may provide as much as 10 W/kg at 10% efficiency. The DIPS technology, at much higher efficiencies, would enable multikilowatt radioisotope power if reliable, long term, continuous operation under space conditions can be assured. Finally, while static AMTEC devices offer the potential for efficiencies comparable to dynamic systems, this technology is the least mature of those discussed, and will require the demonstration of several component technologies in long life tests. RP BANKSTON, CP (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 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. PY 1991 VL 24 BP 161 EP 170 DI 10.1016/0094-5765(91)90163-Y PG 10 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300018 ER PT J AU FARQUHAR, RW AF FARQUHAR, RW TI HALO-ORBIT AND LUNAR-SWINGBY MISSIONS OF THE 1990S SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB A significant number of spacecraft are planning to use halo orbits and lunar-swingby trajectories in the next decade. Four spacecraft will be placed into halo orbits around the Earth's sunward libration point, while two others will be stationed near the Sun-Earth L2 libration point in the distant geomagnetic tail. Six spacecraft, including two of the aforementioned halo orbiters, will make use of lunar-swingby maneuvers to fulfill their mission objectives. Thus, a total of ten spacecraft, five from the Soviet Union, two from Japan, two from the United States, and one from the European Space Agency, will employ halo orbits and/or lunar-swingby trajectories in the 1990's. Pertinent facts are presented for each of these missions. RP FARQUHAR, RW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 23 Z9 23 U1 0 U2 2 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. PY 1991 VL 24 BP 227 EP 234 DI 10.1016/0094-5765(91)90170-A PG 8 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300025 ER PT J AU BURKE, JD BICKLER, DB PIVIROTTO, DL AF BURKE, JD BICKLER, DB PIVIROTTO, DL TI LUNAR ROVER DEVELOPMENTS AT JPL SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB In exploring the Moon, the next logical step after orbital missions such as the Lunar Observer is to make traverses on the surface. Some of the required techniques were demonstrated by two Soviet Lunokhods and three manned Apollo rovers. In the sixties and early seventies JPL conducted a variety of field tests exploring the potential of automated lunar rovers for long-range mobility, navigation, and geological reconnaissance. However, because of the lapse in lunar activities after Apollo 17 (1972) and Luna 24 (1976), much of that work remains unpublished. More recently we have returned to the study of roving missions for both the Moon and Mars. The purposes of the present paper are (a) to summarize the results of previous JPL developments, (b) to describe our current work related to lunar roving missions, and (c) to point toward applications of automated rovers in surveying for future lunar base sites, in prospecting for and using lunar resources, and in resuming the scientific exploration of the Moon. RP BURKE, JD (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 4 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. PY 1991 VL 24 BP 259 EP 266 DI 10.1016/0094-5765(91)90174-4 PG 8 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300029 ER PT J AU HALL, JR HASTRUP, RC AF HALL, JR HASTRUP, RC TI DEEP SPACE TELECOMMUNICATIONS, NAVIGATION, AND INFORMATION MANAGEMENT - SUPPORT OF THE SPACE EXPLORATION INITIATIVE SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB The United States Space Exploration Initiative (SEI) calls for the charting of a new and evolving manned course to the Moon, Mars, and beyond. This paper discusses key challenges in providing effective deep space telecommunications, navigation, and information management (TNIM) architectures and designs for Mars exploration support. The fundamental objectives are to provide the mission with means to monitor and control mission elements, acquire engineering, science, and navigation data, compute state vectors and navigate, and move these data efficiently and automatically between mission nodes for timely analysis and decision-making. Although these objectives do not depart, fundamentally, from those evolved over the past 30 years in supporting deep space robotic exploration, there are several new issues. This paper focuses on summarizing new requirements, identifying related issues and challenges, responding with concepts and strategies which are enabling, and, finally, describing candidate architectures, and driving technologies. The design challenges include the attainment of-. 1) manageable interfaces in a large distributed system, 2) highly unattended operations for in-situ Mars telecommunications and navigation functions, 3) robust connectivity for manned and robotic links, 4) information management for efficient and reliable interchange of data between mission nodes, and 5) an adequate Mars-Earth data rate. RP HALL, JR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 24 BP 267 EP 277 DI 10.1016/0094-5765(91)90175-5 PG 11 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300030 ER PT J AU NICGOSSIAN, AE CHARLES, JB BUNGO, MW LEACHHUNTOON, CS AF NICGOSSIAN, AE CHARLES, JB BUNGO, MW LEACHHUNTOON, CS TI CARDIOVASCULAR FUNCTION IN SPACE-FLIGHT SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB Changes in orthostatic heart rate have been noted universally in Soviet and U.S. crewmembers post space flight. The magnitude of these changes appears to be influenced by mission duration, with increasing orthostatic intolerance for the first 7-1 0 days of flight and then a partial recovery in the orthostatic heart rate response. Fluid loading has been used as a countermeasure to this postflight orthostatic intolerance. Previous reports have documented the effectiveness of this technique, but it has also been noted that the effectiveness of volume expansion diminishes as flight duration exceeds one week. The response of carotid baroreceptor function was investigated utilizing a commercially available neck collar which could apply positive and negative pressure to effect receptor stimulation. Bedrest studies had validated the usefulness and validity of the device. In these studies it was shown that carotid baroreceptor function curves demonstrated less responsiveness to orthostatic stimulation than control individuals. Twelve Space Shuttle crewmembers were examined pre- and postflight from flights lasting from 4-5 days. Plots of baroreceptor function were constructed and plotted as change in R-R interval vs. carotid distending pressure (an orthostatic stimulus). Typical sigmoidal curves were obtained. Postflight the resting heart rate was higher (smaller R-R interval) and the range of R-R value and the slope of the carotid sigmoidal response were both depressed. These changes were not significant immediately postflight (L + O), but did become significant by the second day postflight (L + 2), and remained suppressed for several days thereafter. It is hypothesized that the early adaptation to space flight involves a central fluid shift during the initial days of flight, but subsequent alterations in neural controlling mechanisms (such as carotid baroreceptor function) contribute to orthostatic intolerance. RP NICGOSSIAN, AE (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 24 BP 323 EP 328 DI 10.1016/0094-5765(91)90181-4 PG 6 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300036 ER PT J AU LOFTUS, JP POTTER, AE AF LOFTUS, JP POTTER, AE TI UNITED-STATES STUDIES IN ORBITAL DEBRIS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 41ST INTERNATIONAL ASTRONAUTICAL FEDERATION CONGRESS : SPACE FOR PEACE AND PROGRESS CY OCT 08-12, 1990 CL DRESDEN, GER DEM REP AB The U.S. has been conducting studies of the natural meteoritic environment since the beginning of the space program. In the early 1970's NASA began to study the issues of debris generated from man's activities in space. These studies have covered all aspects of the issue from the development of observation capabilities, through the modeling of the space environment and the characterization of breakup events, laboratory hypervelocity impact testing, arid the exposure of materials in space. This work has been the basis of the U.S. National Space Policy requirement that all sectors of the U.S. space program minimize debris. It is also the basis of the current design approach to the Space Station Freedom provisions for protection against meteoroids and debris. There is now a substantial amount of work being done in the study of orbital debris arid shielding systems by the ESA and NASDA participants in the station program and by the industrial and university teams that support the agencies. The Long Duration Exposure Facility (LDEF), was recovered in January 1990, after five years and seven months on orbit and is now being studied. It is a major new source of data as to the current environment. RP LOFTUS, JP (reprint author), LYNDON B JOHNSON SPACE CTR,HOUSTON,TX, 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. PY 1991 VL 24 BP 333 EP 341 DI 10.1016/0094-5765(91)90183-6 PG 9 WC Engineering, Aerospace SC Engineering GA FP763 UT WOS:A1991FP76300038 ER PT J AU WHITE, RJ LEONARD, JI SRINIVASAN, RS CHARLES, JB AF WHITE, RJ LEONARD, JI SRINIVASAN, RS CHARLES, JB TI MATHEMATICAL-MODELING OF ACUTE AND CHRONIC CARDIOVASCULAR CHANGES DURING EXTENDED DURATION ORBITER (EDO) FLIGHTS SO ACTA ASTRONAUTICA LA English DT Article AB The Extended Duration Orbiter (EDO) program aims to extend the capability of the Shuttle orbiter beyond its current 7-10 day limit on mission duration. This goal is to be accomplished in steps, partly due to our limited knowledge of the physiological changes resulting from long-term exposure to weightlessness and their likely influence on critical mission operations involved in EDO flights. Answers to questions related to physiologic adaptation to weightlessness are being actively sought at the present time to help implement the EDO program. In the cardiovascular area, the loss of orthostatic tolerance is a medical concern because of its potential adverse effects on crew performance and safety during reentry and following return to earth. Flight and ground-based physiologic studies are being planned to understand the mechanism and time course of spaceflight-induced orthostatic intolerance and to develop effective contermeasures for improving postflight cardiovascular performance. Where feasible, these studies are aided by theoretical analyses using mathematical modeling and computer simulation of physiological systems. This paper is concerned with the application of proven models of circulatory and cardiovascular systems in the analysis of chronic cardiovascular changes under weightless conditions. RP WHITE, RJ (reprint author), NASA,DIV LIFE SCI,WASHINGTON,DC 20546, USA. NR 0 TC 19 Z9 19 U1 1 U2 2 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. PY 1991 VL 23 BP 41 EP 51 DI 10.1016/0094-5765(91)90098-P PG 11 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700008 PM 11537147 ER PT J AU THORNTON, WE URI, JJ AF THORNTON, WE URI, JJ TI OCULOMOTOR FUNCTION DURING SPACE-FLIGHT AND SUSCEPTIBILITY TO SPACE MOTION SICKNESS SO ACTA ASTRONAUTICA LA English DT Article AB Horizontal vestibulo-ocular reflex (VOR) and saccadic eye movements (SEM) were studied in 18 subjects before and during five Space Shuttle missions to evaluate the effects of weightlessness and correlations between results and susceptibility to and actual presence of space motion sickness (SMS). Active sinusoidal head oscilation was the stimulus for VOR tests with vision (VVOR), with eyes shaded (VOR-ES), and VOR suppression (VOR-S). Eye movements were recorded by electrooculography and head position by a potentiometer. No pathological nystagmus or other abnormal eye movements were seen. No significant in-flight changes were seen in the gain, phase shift or waveform of VVOR, VOR-ES or VOR-S. Statistically significant increases in saccadic latency and decreases in saccadic velocity were seen, with no change in saccadic accuracy. Preflight differences between SMS susceptible and non-susceptible subjects were noted only in VOR-S, with less complete suppression in susceptible subjects, a finding also seen in flight. During flight, VVOR gain was significantly increased in three non-affected subjects. Saccades of SMS-affected subjects showed increased latency and velocity and decreased accuracy compared to saccades of unaffected subjects. RP THORNTON, WE (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 4 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 23 BP 53 EP 61 DI 10.1016/0094-5765(91)90099-Q PG 9 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700009 PM 11537148 ER PT J AU LEACH, CS AF LEACH, CS TI METABOLISM AND BIOCHEMISTRY IN HYPOGRAVITY SO ACTA ASTRONAUTICA LA English DT Article AB The headward shift of body fluid and increase in stress-related hormones that occur in hypogravity bring about a number of changes in metabolism and biochemistry of the human body. Such alterations may have important effects on health during flight and during a recovery period after return to Earth. Body fluid and electrolytes are lost, and blood levels of several hormones that control metabolism are altered during space flight. Increased serum calcium may lead to an increased risk of renal stone formation during flight, and altered drug metabolism could influence the efficacy of therapeutic agents. Orthostatic intolerance and an increased risk of fracturing weakened bones are concerns at landing. It is important to understand biochemistry and metabolism in hypogravity so that clinically important developments can be anticipated and prevented or ameliorated. RP LEACH, CS (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES,HOUSTON,TX 77058, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 23 BP 105 EP 108 DI 10.1016/0094-5765(91)90105-E PG 4 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700015 PM 11537110 ER PT J AU WALIGORA, JM HORRIGAN, DJ NICOGOSSIAN, A AF WALIGORA, JM HORRIGAN, DJ NICOGOSSIAN, A TI THE PHYSIOLOGY OF SPACECRAFT AND SPACE SUIT ATMOSPHERE SELECTION SO ACTA ASTRONAUTICA LA English DT Article AB The majority of the environmental factors which comprise the spacecraft and space suit environments can be controlled at "Earth normal" values, at optimum values, or at other values decided upon by spacecraft designers. Factors which are considered in arriving at control values and control ranges of these parameters include physiological, engineering, operational cost, and safety considerations. Several of the physiologic considerations, including hypoxia and hyperoxia, hypercapnia, temperature regulation, and decompression sickness are identified and their impact on space craft and space suit atmosphere selection are considered. The past experience in controlling these parameters in U.S. and Soviet spacecraft and space suits and the associated physiological responses are reviewed. Current areas of physiological investigation relating to environmental factors in spacecraft are discussed, particularly decompression sickness which can occur as a result of change in pressure from Earth to spacecraft or spacecraft to space suit. Physiological considerations for long-term lunar or Martian missions will have different impacts on atmosphere selection and may result in the selection of atmosphere different than those currently in use. RP WALIGORA, JM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,INST SPACE BIOMED RES,HOUSTON,TX 77058, USA. NR 0 TC 7 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. PY 1991 VL 23 BP 171 EP 177 DI 10.1016/0094-5765(91)90116-M PG 7 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700026 PM 11537121 ER PT J AU NACHTWEY, DS YANG, TC AF NACHTWEY, DS YANG, TC TI RADIOLOGICAL HEALTH RISKS FOR EXPLORATORY CLASS MISSIONS IN SPACE SO ACTA ASTRONAUTICA LA English DT Article AB Crewmembers on missions to the Moon or Mars will be unavoidably exposed to ionizing radiation as they pass through the Van Allen belts and the Galactic Cosmic Ray (GCR) flux. There is the possibility for exposure to proton radiation from Solar Particle Events (SPE). Using absorbed doses and ICRP 26, Linear Energy Transfer (LET)-dependent quality factors, the following dose-equivalents are estimated: In a spacecraft with 0.75 cm aluminum walls (2 g/cm2) at solar minimum, the lunar round trip dose-equivalent is less than 0.05 Sv. During a Mars mission the estimated dose-equivalents are: outbound (Van Allen Belts) < 0.02 Sv; Earth to Mars (205 days exposure to free space GCR) 0.32 Sv; 30 days on the Martian surface (GCR) 0.023 Sv; Mars to Earth (225 days exposure to free space) 0.35 Sv; and through the Van Allen Belts 0.02 Sv. Conventionally, the total of 0.73 Sv over 460 days could be expected to increase the risk of cancer mortality in a 35-year old male astronaut by about one percent. However three-fourths of the dose-equivalent in free space is contributed by high LET heavy ions (Z greater-than-or-equal-to 3) and target fragments with average quality factors of 10.3 and 20 respectively. The biological effectiveness of these radiations is poorly understood; so the quality factors are set at conservatively very high values. The entire concept of absorbed dose/quality factor/dose-equivalent as applied to GCR must be reconsidered. RP NACHTWEY, DS (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,DIV MED SCI,HOUSTON,TX 77058, USA. NR 0 TC 9 Z9 9 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. PY 1991 VL 23 BP 227 EP 231 DI 10.1016/0094-5765(91)90122-L PG 5 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700032 PM 11537128 ER PT J AU SULZMAN, FM WOLFE, JW AF SULZMAN, FM WOLFE, JW TI NEUROSCIENCES RESEARCH IN SPACE - FUTURE-DIRECTIONS SO ACTA ASTRONAUTICA LA English DT Article AB Future research in the neurosciences can best be understood in the context of NASA's life sciences goals in the near term (1990-95), mid term (1995-2000), and long term (2000 and beyond). Since NASA is planning short-duration Spacelab and International Microgravity Laboratory (IML) flights for many years to come, the acute effects of exposure to microgravity will continue to be of experimental and operational interest in the near term. To this end, major new areas of research will be devoted to ground-based studies of preflight adaptation trainers and their efficacy in preventing or reducing the incidence of space motion sickness. In addition, an extensive series of studies of the vestibular system will be conducted inflight on the IML-1 mission. The IML-2 mission will emphasize behavior and performance, biological rhythms, and further vestibular studies. In the mid-term period, Spacelab missions will employ new technology such as magnetic recording techniques in order to evaluate changes in the processing of sensory and motor inputs at the brainstem and cortical level during exposure to microgravity. Two Space Life Sciences (SLS) missions planned for the mid to late 1990's, SLS-4 and SLS-5, will utilize an onboard centrifuge facility that will enable investigators to study the effects of partial gravity on sensory and motor function. In the long term (2000 and beyond), Space Station Freedom and long-duration missions will provide opportunities to explore new options in the neurosciences, such as sensory substitution and augmentation, through the use of physical sensors to provide three-dimensional tactile-visual, tactile-auditory and tactile-somatosensory inputs. The use of this technology will be extremely important in the area of robotic telepresence. Finally, Space Station Freedom and proposed LifeSat missions will provide neuroscientists the opportunity to study the effects of partial gravity and microgravity on neuronal plasticity. RP SULZMAN, FM (reprint author), NASA HEADQUARTERS,SPACE MED & BIOL BRANCH,WASHINGTON,DC 20546, USA. NR 0 TC 3 Z9 3 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. PY 1991 VL 23 BP 289 EP 293 DI 10.1016/0094-5765(91)90130-W PG 5 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700040 PM 11537137 ER PT J AU BALLARD, RW SOUZA, KA AF BALLARD, RW SOUZA, KA TI MAN IN SPACE - THE USE OF ANIMAL-MODELS SO ACTA ASTRONAUTICA LA English DT Article AB Animals have traditionally preceded man into space. During animal and human travels in space over the past almost 30 years, numerous anatomical, physiological, and biochemical changes have been observed. In order to safely qualify humans for extended duration space missions, scientific research needs to be performed. It may be possible to achieve many of these research goals with flight crews serving as experimental subjects; however, to do this with human subjects alone is impractical. Therefore, the use of animal surrogates as experimental subjects is essential to provide the missing information on the effects of spaceflights, to validate counter-measures, and to test medical treatment techniques which will be necessary for long duration missions. This research to assure human health, safety, and productivity in future extended duration space flights will include flights on NASA's Space Shuttle, unmanned biosatellites, and the Space Station Freedom. RP BALLARD, RW (reprint author), NASA,AMES RES CTR,SPACE LIFE SCI PAYLOADS OFF,MOFFETT FIELD,CA 94035, USA. NR 0 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PY 1991 VL 23 BP 295 EP 297 DI 10.1016/0094-5765(91)90131-N PG 3 WC Engineering, Aerospace SC Engineering GA EU477 UT WOS:A1991EU47700041 PM 11537138 ER PT J AU FREED, AD CHABOCHE, JL WALKER, KP AF FREED, AD CHABOCHE, JL WALKER, KP TI A VISCOPLASTIC THEORY WITH THERMODYNAMIC CONSIDERATIONS SO ACTA MECHANICA LA English DT Article ID CONSTITUTIVE-EQUATIONS; NONELASTIC DEFORMATION; CYCLIC PLASTICITY; MODEL; METALS; CREEP; RULES; FLOW AB A thermodynamic foundation using the concept of internal state variables is given for a general theory of viscoplasticity for initially isotropic materials. Three, fundamental, internal, state variables are admitted; they are: a tensorial back stress for kinematic effects, and scalar drag and yield strengths for isotropic effects. All three are considered to evolve phenomenologically according to competitive processes between strain hardening, deformation induced dynamic recovery, and thermally induced static recovery. Within this phenomenological framework, a thermodynamically admissible set of evolution equations is proposed. The theory allows each of the three internal variables to be composed as a sum of independently evolving constituents. The evolution of internal state can also include terms that vary linearly with the external variable rates, whose presence affects the energy dissipation properties of a material. C1 ENGN SCI SOFTWARE INC,SMITHFIELD,RI 02917. OFF NATL ETUD & RECH AEROSP,F-92322 CHATILLON,FRANCE. RP FREED, AD (reprint author), NATL AERONAUT & SPACE ADM,LEWIS RES CTR,CLEVELAND,OH 44135, USA. RI Chaboche, Jean-Louis/A-6755-2012; OI Freed, Alan/0000-0002-3492-0628 NR 70 TC 41 Z9 41 U1 0 U2 10 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0001-5970 J9 ACTA MECH JI Acta Mech. PY 1991 VL 90 IS 1-4 BP 155 EP 174 DI 10.1007/BF01177406 PG 20 WC Mechanics SC Mechanics GA GL860 UT WOS:A1991GL86000012 ER PT J AU ROSS, MD CUTLER, L DOSHAY, D CHENG, R NADDAF, A AF ROSS, MD CUTLER, L DOSHAY, D CHENG, R NADDAF, A TI A NEW THEORY OF MACULAR ORGANIZATION BASED ON COMPUTER-ASSISTED 3-D RECONSTRUCTION, MONTE-CARLO SIMULATION AND SYMBOLIC MODELING OF VESTIBULAR MACULAS SO ACTA OTO-LARYNGOLOGICA LA English DT Article; Proceedings Paper CT 16TH MEETING OF THE BARANY SOC ON VESTIBULAR AND EQUILIBRIUM RESEARCH : BASIC AND CLINICAL IMPLICATIONS CY MAY 28-30, 1990 CL TOKYO, JAPAN SP BARANY SOC DE 3-D RECONSTRUCTIONS; CONSTRAINED RANDOMNESS; NEURAL BUNDLING; C-SYNAPSES; CHANNELED CIRCUITS; DISTRIBUTED MODIFYING CIRCUITS ID GENERATED IMAGERY; COMPONENTS; RAT C1 STERLING SOFTWARE,PALO ALTO,CA 94303. RP ROSS, MD (reprint author), NASA,AMES RES CTR,CTR BIOCOMPUTAT,MAIL STOP 261-2,MOFFETT FIELD,CA 94035, USA. NR 22 TC 3 Z9 3 U1 0 U2 0 PU SCANDINAVIAN UNIVERSITY PRESS PI OSLO PA PO BOX 2959 TOYEN, JOURNAL DIVISION CUSTOMER SERVICE, N-0608 OSLO, NORWAY SN 0001-6489 J9 ACTA OTO-LARYNGOL JI Acta Oto-Laryngol. PY 1991 SU 481 BP 11 EP 14 PG 4 WC Otorhinolaryngology SC Otorhinolaryngology GA FR819 UT WOS:A1991FR81900004 ER PT J AU MERFELD, DM YOUNG, LR TOMKO, DL PAIGE, GD AF MERFELD, DM YOUNG, LR TOMKO, DL PAIGE, GD TI SPATIAL ORIENTATION OF VOR TO COMBINED VESTIBULAR STIMULI IN SQUIRREL-MONKEYS SO ACTA OTO-LARYNGOLOGICA LA English DT Article; Proceedings Paper CT 16TH MEETING OF THE BARANY SOC ON VESTIBULAR AND EQUILIBRIUM RESEARCH : BASIC AND CLINICAL IMPLICATIONS CY MAY 28-30, 1990 CL TOKYO, JAPAN SP BARANY SOC AB The interaction of angular and linear stimuli produces a complex alignment of spatial orientation and the VOR. This phenomenon was studied by measuring three dimensional eye movements in 6 squirrel monkeys during centrifugation in the dark. The axis of eye rotation was always aligned with gravity and with the spinal axis of the upright monkeys. The erect monkeys were oriented such that they were either facing toward the direction of motion or were facing away from the motion. Angular velocity trapezoids were utilized as the motion stimuli with a ramp acceleration of 10-degrees/s2 to a constant velocity of 200-degrees/s. This yields a final centripetal acceleration of 1 g. The orientation of centripetal acceleration dramatically altered the VOR by changing the axis of eye rotation, the peak value of slow phase eye velocity, and the time constant of per-rotary decay. The axis of eye rotation always tended to align with gravito-inertial force, the peak value of slow phase eye velocity was greater when the monkey faced the motion than when it faced away from the motion, and the time constant of decay was smaller when the monkey faced the motion than when it faced away from the motion. These findings were statistically significant (p < 0.05) and were consistent across all monkeys. The data also indicate that the VOR may be separated into two reflexes, a linear reflex and a rotational reflex. The linear reflex decays as the axis of eye rotation aligns with gravito-inertial force (GIF). These results indicate that GIF is resolved into two components; one representing an internal estimate of linear acceleration and one representing an internal estimate of gravity. C1 NASA,AMES RES CTR,VESTIBULAR RES FACIL,MOFFETT FIELD,CA 94035. WASHINGTON UNIV,DEPT OTOLARYNGOL,ST LOUIS,MO 63130. RP MERFELD, DM (reprint author), MIT,MAN VEHICLE LAB,CAMBRIDGE,MA 02139, USA. NR 9 TC 8 Z9 8 U1 0 U2 0 PU SCANDINAVIAN UNIVERSITY PRESS PI OSLO PA PO BOX 2959 TOYEN, JOURNAL DIVISION CUSTOMER SERVICE, N-0608 OSLO, NORWAY SN 0001-6489 J9 ACTA OTO-LARYNGOL JI Acta Oto-Laryngol. PY 1991 SU 481 BP 287 EP 292 PG 6 WC Otorhinolaryngology SC Otorhinolaryngology GA FR819 UT WOS:A1991FR81900074 ER PT J AU BERATAN, DN ONUCHIC, JN AF BERATAN, DN ONUCHIC, JN TI ELECTRON-TRANSFER - FROM MODEL COMPOUNDS TO PROTEINS SO ADVANCES IN CHEMISTRY SERIES LA English DT Article ID CYTOCHROME-C DERIVATIVES; TUNNELING PATHWAYS; REACTION DYNAMICS; TRANSFER KINETICS; RATE-CONSTANT; THROUGH-BOND; MOLECULES; QUANTUM; SYSTEMS; CHEMISTRY AB We summarize the formulation of the protein-mediated electronic coupling calculation as a two-level system with weakly interacting bridge units. Using model compounds as a starting point from which to derive coupling parameters, we present a strategy for defining the pathways for electron tunneling in biological and biomimetic systems. The specific bonding and nonbonding interactions in cytochrome c and myoglobin that mediate the tunneling between the porphyrin and an attached transition metal probe are described. The method appears to succeed where traditional structureless tunneling barrier or periodic bridge models are not adequate. An algorithm to search for these tunneling pathways in proteins is described, and the nature of the paths is discussed. C1 UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. UNIV SAO PAULO,INST FIS & QUIM,BR-13560 SAO CARLOS,SP,BRAZIL. CALTECH,JET PROP LAB,PASADENA,CA 91109. RI Beratan, David/C-5098-2011 NR 58 TC 5 Z9 5 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-2393 J9 ADV CHEM SER JI Adv. Chem. Ser. PY 1991 IS 228 BP 71 EP 90 PG 20 WC Chemistry, Multidisciplinary SC Chemistry GA GD629 UT WOS:A1991GD62900006 ER PT J AU GULATI, S BARHEN, J IYENGAR, SS AF GULATI, S BARHEN, J IYENGAR, SS TI NEUROCOMPUTING FORMALISMS FOR COMPUTATIONAL LEARNING AND MACHINE INTELLIGENCE SO ADVANCES IN COMPUTERS LA English DT Review ID CONTENT-ADDRESSABLE MEMORY; BASIC NETWORK PRINCIPLES; NEURAL NETWORKS; REDUNDANT MANIPULATORS; PATTERN-RECOGNITION; VOLUNTARY MOVEMENT; SENSITIVITY THEORY; SELF-ORGANIZATION; MOBILE ROBOT; TIME-SERIES C1 LOUISIANA STATE UNIV,DEPT COMP SCI,ROBOT RES LAB,BATON ROUGE,LA 70803. RP GULATI, S (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 308 TC 5 Z9 5 U1 0 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0065-2458 J9 ADV COMPUT JI Adv. Comput. PY 1991 VL 33 BP 173 EP 245 DI 10.1016/S0065-2458(08)60167-9 PG 73 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA GN960 UT WOS:A1991GN96000004 ER PT B AU HINMAN, EM AF HINMAN, EM BE STRIMAITIS, JR LITTLE, JN TI ROBOT-TENDED CRYSTAL-GROWTH IN A SPACE-BASED LABORATORY SO ADVANCES IN LABORATORY AUTOMATION ROBOTICS, VOL 7 SE ADVANCES IN LABORATORY AUTOMATION ROBOTICS LA English DT Proceedings Paper CT 8TH INTERNATIONAL SYMP ON LABORATORY ROBOTICS CY SEP 16-19, 1990 CL BOSTON, MA RP HINMAN, EM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,INFORMAT & ELECTR SYST LAB,CONTROL ELECTR BRANCH,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ZYMARK CORP PI HOPKINTON PA HOPKINTON BN 0-931565-06-5 J9 ADV LAB AUT PY 1991 BP 715 EP 726 PG 12 WC Energy & Fuels; Medical Laboratory Technology; Pharmacology & Pharmacy SC Energy & Fuels; Medical Laboratory Technology; Pharmacology & Pharmacy GA BT90W UT WOS:A1991BT90W00042 ER PT J AU CELENLIGIL, MC MOSS, JN BLANCHARD, RC AF CELENLIGIL, MC MOSS, JN BLANCHARD, RC TI 3-DIMENSIONAL RAREFIED FLOW SIMULATIONS FOR THE AEROASSIST FLIGHT EXPERIMENT VEHICLE SO AIAA JOURNAL LA English DT Article AB Hypersonic rarefied flow about the Aeroassist Flight Experiment vehicle has been investigated using a three-dimensional direct simulation Monte Carlo method. Calculations are performed for the transitional flows encountered during the vehicle's atmospheric entry for altitudes of 110 and 100 km with an entry velocity of 9.9 km/s. The simulations are performed using a five-species reacting gas model that accounts for rotational and vibrational internal energies. The solutions indicate that dissociation in important at altitudes of 110 km and below. Results are presented for surface presures, convective heating, flowfield structure, and aerodynamic coefficient variations with altitude. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP CELENLIGIL, MC (reprint author), VIGYAN RES ASS INC,HAMPTON,VA 23666, USA. NR 16 TC 8 Z9 8 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 1991 VL 29 IS 1 BP 52 EP 57 DI 10.2514/3.10544 PG 6 WC Engineering, Aerospace SC Engineering GA EY063 UT WOS:A1991EY06300007 ER PT J AU NAIK, RA CREWS, JH AF NAIK, RA CREWS, JH TI STRESS-ANALYSIS METHOD FOR CLEARANCE-FIT JOINTS WITH BEARING-BYPASS LOADS SO AIAA JOURNAL LA English DT Article AB In multi-fastener joints, fastener holes may be subjected to combined bearing loads and bypass loads that are reacted elsewhere in the joint. The analysis of a joint with such loading is complicated by the usual clearance between the hole and the fastener. A simple analysis method for clearance-fit joints with bearing-bypass loading is presented in this paper. This analysis uses an inverse formulation and can be implemented with most general purpose finite element programs. A quasi-isotropic graphite/epoxy plate was analyzed with a rigid, frictionless bolt. Computed results showed that the contact angle and the peak stresses at the hole were strongly influenced by the bearing-bypass stress ratio. Tension and compression bearing-bypass loading had opposite effects on the contact angle. For large compressive bearing-bypass loads, the hole tended to close on the fastener leading to dual contact. Dual contact reduced the stress concentration at the fastener and would, therefore, increase joint strength. The results illustrate the general importance of accounting for bolt-hole clearance and contact to accurately compute bolt-hole stresses. C1 NASA,LANGLEY RES CTR,DIV MAT,HAMPTON,VA 23665. RP NAIK, RA (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 17 TC 8 Z9 8 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 1991 VL 29 IS 1 BP 89 EP 95 DI 10.2514/3.10549 PG 7 WC Engineering, Aerospace SC Engineering GA EY063 UT WOS:A1991EY06300012 ER PT J AU DENNING, PJ AF DENNING, PJ TI BEYOND FORMALISM SO AMERICAN SCIENTIST LA English DT Editorial Material RP DENNING, PJ (reprint author), NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035, USA. NR 13 TC 4 Z9 4 U1 0 U2 0 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 SN 0003-0996 J9 AM SCI JI Am. Scientist PD JAN-FEB PY 1991 VL 79 IS 1 BP 8 EP 10 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FB848 UT WOS:A1991FB84800007 ER PT J AU ARAKI, S AF ARAKI, S TI DYNAMICS OF PLANETARY RINGS SO AMERICAN SCIENTIST LA English DT Article ID SATURNS RINGS; VOYAGER-2 ENCOUNTER; PARTICLE DISKS; SIMULATIONS; COLLISIONS; STABILITY; EVOLUTION; SYSTEM RP ARAKI, S (reprint author), CALTECH,JET PROP LAB,MS 183-501,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 36 TC 9 Z9 9 U1 0 U2 2 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 SN 0003-0996 J9 AM SCI JI Am. Scientist PD JAN-FEB PY 1991 VL 79 IS 1 BP 44 EP 59 PG 16 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA FB848 UT WOS:A1991FB84800012 ER PT J AU PACHER, T STEINSCHABES, JA AF PACHER, T STEINSCHABES, JA TI ON THE LOCALITY OF THE NO HAIR CONJECTURE AND THE MEASURE OF THE UNIVERSE SO ANNALEN DER PHYSIK LA English DT Article ID HOMOGENEOUS COSMOLOGICAL MODELS; ANISOTROPIC COSMOLOGIES; INFLATION; CONSTANT; ISOTROPIZATION AB We reanalyze the recently proposed proof by Jensen and Stein-Schabes [1] of the No Hair Theorem for inhomogeneous spacetimes, putting a special emphasis on the asymptotic behaviour of the shear and curvature. We conclude that the theorem only holds locally and estimate the minimum size a region should be in order for it to inflate. We discuss in some detail the assumptions used in the theorem. In the last section We speculate about the possible measure of the set of spacetimes that would undergo inflation. C1 NASA,CTR FERMILAB ASTROPHYS,BATAVIA,IL. RP PACHER, T (reprint author), UNIV HEIDELBERG,INST PHYS CHEM,NEUENHEIMER FELD 253,W-6900 HEIDELBERG,GERMANY. NR 29 TC 0 Z9 0 U1 0 U2 0 PU JOHANN AMBROSIUS BARTH VERLAG PI HEIDELBERG PA IM WEIHER 10, D-69121 HEIDELBERG, GERMANY SN 0003-3804 J9 ANN PHYS-LEIPZIG JI Ann. Phys.-Leip. PY 1991 VL 48 IS 8 BP 518 EP 526 PG 9 WC Physics, Multidisciplinary SC Physics GA HF096 UT WOS:A1991HF09600002 ER PT J AU NETTO, DJ CHEN, PCY SOBIN, SS LEE, JY AF NETTO, DJ CHEN, PCY SOBIN, SS LEE, JY TI DEMONSTRATION OF UNIFORM CAPILLARY BASAL LAMINA THICKNESS BY COMPUTER-TECHNOLOGY SO ANNALS OF BIOMEDICAL ENGINEERING LA English DT Article DE BASAL LAMINA; CAPILLARY; COMPUTER-AIDED; IMAGE PROCESSING; GEOMETRIC CORRECTION AB Blood capillaries are assumed to be circular cylinders composed of an inner layer of endothelial cells surrounded by an acellular uniformly thick basal lamina. The capillary basal lamina is the structural and functional interface between the capillary endothelial cells and the adjacent extracellular matrix, important in growth and control mechanisms of the endothelial cell. Capillaries examined in electron micrographs are cut randomly and a projected image of a capillary other than perpendicular to its long axis will produce artifactual thickening of the assumed uniformly thick basal lamina. We have developed an interactive computer program to determine the thickness of the capillary basal lamina that corrects the thickness resulting from the sectioning artifact. We have applied this methodology to demonstrate that the basal lamina of the pancreatic capillaries of the rat are uniformly thick. C1 UNIV SO CALIF,DEPT PHYSIOL & BIOPHYS,CARDIOVASC RES LAB,AMER HEART ASSOC,LOS ANGELES,CA 90089. UNIV CALIF SAN DIEGO,SAN DIEGO,CA 92103. CALTECH,JET PROP LAB,MED IMAGE FACIL,PASADENA,CA 91109. FU NHLBI NIH HHS [HL 42073]; NIA NIH HHS [AG 02970]; PHITPO CDC HHS [5 K06 HK0070064] NR 9 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE INC PI CAMBRIDGE PA 238 MAIN ST, CAMBRIDGE, MA 02142 SN 0090-6964 J9 ANN BIOMED ENG JI Ann. Biomed. Eng. PY 1991 VL 19 IS 2 BP 209 EP 217 DI 10.1007/BF02368470 PG 9 WC Engineering, Biomedical SC Engineering GA FE599 UT WOS:A1991FE59900007 PM 2048778 ER PT J AU TURCO, RP TOON, OB ACKERMAN, TP POLLACK, JB SAGAN, C AF TURCO, RP TOON, OB ACKERMAN, TP POLLACK, JB SAGAN, C TI NUCLEAR WINTER - PHYSICS AND PHYSICAL-MECHANISMS SO ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES LA English DT Review DE AEROSOLS AND CLIMATE; CLIMATE PROCESSES; CLIMATE MODELING; EFFECTS OF NUCLEAR WAR ID GENERAL-CIRCULATION MODEL; FRACTAL CLUSTERS; SMOKE INJECTIONS; WAR; AEROSOLS; CONSEQUENCES; SIMULATIONS; CLIMATE; ICE; ATMOSPHERE C1 NASA,AMES RES CTR,DIV EARTH SYST SCI,MOFFETT FIELD,CA 94035. PENN STATE UNIV,DEPT METEOROL,UNIVERSITY PK,PA 16802. NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. CORNELL UNIV,PLANETARY STUDIES LAB,ITHACA,NY 14853. RP TURCO, RP (reprint author), UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,LOS ANGELES,CA 90024, USA. NR 80 TC 13 Z9 13 U1 4 U2 7 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 0084-6597 J9 ANNU REV EARTH PL SC JI Annu. Rev. Earth Planet. Sci. PY 1991 VL 19 BP 383 EP 422 DI 10.1146/annurev.earth.19.1.383 PG 40 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA FL552 UT WOS:A1991FL55200015 ER PT J AU BUSHNELL, DM MOORE, KJ AF BUSHNELL, DM MOORE, KJ TI DRAG REDUCTION IN NATURE SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE SWIMMING; FLYING; RESISTANCE MINIMIZATION ID FORMATION FLIGHT; FISH; PISCES; BIRDS; HISTOCHEMISTRY; BUOYANCY; SKIN C1 CORTANA CORP,FALLS CHURCH,VA 22046. RP BUSHNELL, DM (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,HAMPTON,VA 23665, USA. NR 71 TC 106 Z9 110 U1 3 U2 28 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1991 VL 23 BP 65 EP 79 DI 10.1146/annurev.fluid.23.1.65 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA ET750 UT WOS:A1991ET75000004 ER PT J AU SPEZIALE, CG AF SPEZIALE, CG TI ANALYTICAL METHODS FOR THE DEVELOPMENT OF REYNOLDS-STRESS CLOSURES IN TURBULENCE SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE TURBULENCE MODELING; K-EPSILON MODEL; 2-EQUATION MODELS; 2ND-ORDER CLOSURES ID TWO-DIMENSIONAL TURBULENCE; K-EPSILON MODEL; CHANNEL FLOW; SHEAR FLOWS; ISOTROPIC TURBULENCE; NUMERICAL-SIMULATION; TRANSPORT EQUATIONS; 2ND-MOMENT CLOSURE; DISSIPATION-RATE; ROTATING FRAME RP SPEZIALE, CG (reprint author), NASA, LANGLEY RES CTR, INST COMP APPL SCI & ENGN, HAMPTON, VA 23665 USA. NR 121 TC 356 Z9 362 U1 3 U2 27 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1991 VL 23 BP 107 EP 157 DI 10.1146/annurev.fluid.23.1.107 PG 51 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA ET750 UT WOS:A1991ET75000006 ER PT J AU KLEISER, L ZANG, TA AF KLEISER, L ZANG, TA TI NUMERICAL-SIMULATION OF TRANSITION IN WALL-BOUNDED SHEAR FLOWS SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE TRANSITION TO TURBULENCE; NONLINEAR STABILITY; NAVIER-STOKES EQUATIONS; NUMERICAL METHODS; BOUNDARY LAYERS ID PLANE POISEUILLE FLOW; TAYLOR-VORTEX FLOW; LAMINAR TURBULENT TRANSITION; LOW REYNOLDS-NUMBER; CHANNEL FLOW; LAYER STABILITY; SECONDARY INSTABILITY; COUETTE-FLOW; INCOMPRESSIBLE-FLOW; GROOVED CHANNELS C1 NASA, LANGLEY RES CTR, THEORET FLOW PHYS BRANCH, HAMPTON, VA 23665 USA. RP KLEISER, L (reprint author), DLR, INST THEORET FLUID MECH, W-3400 GOTTINGEN, GERMANY. NR 162 TC 162 Z9 166 U1 1 U2 17 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1991 VL 23 BP 495 EP 537 PG 43 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA ET750 UT WOS:A1991ET75000017 ER PT J AU ROBINSON, SK AF ROBINSON, SK TI COHERENT MOTIONS IN THE TURBULENT BOUNDARY-LAYER SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE TURBULENT STRUCTURE ID SIMULTANEOUS FLOW VISUALIZATION; PRESSURE-FLUCTUATIONS BENEATH; LOW REYNOLDS-NUMBERS; LARGE-SCALE MOTION; OPEN-CHANNEL FLOW; NEAR-WALL REGION; SHEAR-FLOW; STREAMWISE VORTICES; INTERMITTENT REGION; BURSTING FREQUENCY RP ROBINSON, SK (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 154 TC 1190 Z9 1227 U1 17 U2 122 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1991 VL 23 BP 601 EP 639 DI 10.1146/annurev.fl.23.010191.003125 PG 39 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA ET750 UT WOS:A1991ET75000019 ER PT J AU TOOMARIAN, N BARHEN, J AF TOOMARIAN, N BARHEN, J TI ADJOINT-OPERATORS AND NONADIABATIC LEARNING ALGORITHMS IN NEURAL NETWORKS SO APPLIED MATHEMATICS LETTERS LA English DT Article AB Adjoint sensitivity equations are presented, which can be solved simultaneously (i.e., forward in time) with the dynamics of a nonlinear neural network. These equations provide the foundations for a new methodology which enables the implementation of temporal learning algorithms in a highly efficient manner. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,DIV ENGN & APPL SCI,PASADENA,CA 91109. NR 15 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0893-9659 J9 APPL MATH LETT JI Appl. Math. Lett. PY 1991 VL 4 IS 2 BP 69 EP 73 DI 10.1016/0893-9659(91)90172-R PG 5 WC Mathematics, Applied SC Mathematics GA FT971 UT WOS:A1991FT97100018 ER PT J AU SALAS, MD AF SALAS, MD TI SPECIAL ISSUE ON - TRANSITION TO TURBULENCE SO APPLIED NUMERICAL MATHEMATICS LA English DT Editorial Material RP SALAS, MD (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,THEORET AERODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 0 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 1991 VL 7 IS 1 BP 1 EP 1 DI 10.1016/0168-9274(91)90100-E PG 1 WC Mathematics, Applied SC Mathematics GA EV492 UT WOS:A1991EV49200001 ER PT J AU ZANG, TA AF ZANG, TA TI ON THE ROTATION AND SKEW-SYMMETRICAL FORMS FOR INCOMPRESSIBLE-FLOW SIMULATIONS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID NAVIER-STOKES EQUATIONS; NUMERICAL-SIMULATION; TURBULENT FLOWS AB A variety of numerical simulations of transition and turbulence in incompressible flow are presented to compare the commonly used rotation form with the skew-symmetric (and other) forms of the nonlinear terms. The results indicate that the rotation form is much less accurate than the other forms for spectral algorithms which include aliasing errors. For de-aliased methods the difference is minimal. RP ZANG, TA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 17 TC 79 Z9 81 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JAN PY 1991 VL 7 IS 1 BP 27 EP 40 DI 10.1016/0168-9274(91)90102-6 PG 14 WC Mathematics, Applied SC Mathematics GA EV492 UT WOS:A1991EV49200003 ER PT J AU STREETT, CL HUSSAINI, MY AF STREETT, CL HUSSAINI, MY TI A NUMERICAL-SIMULATION OF THE APPEARANCE OF CHAOS IN FINITE-LENGTH TAYLOR-COUETTE FLOW SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID NAVIER-STOKES EQUATIONS; VORTEX FLOW; BIFURCATION PHENOMENA; VISCOUS-FLUID; STEADY FLOWS; TRANSITION; GEOMETRIES; VORTICES; SYSTEM AB Taylor-Couette flow, the shear-driven flow between concentric cylinders, exhibits a wide variety of instabilities and modal changes, especially for the case of finite length to gap ratio. The numerical simulations presented here capture many of the experimentally observed features, including the moderately high Reynolds number regime in which temporally aperiodic behavior is seen. The exponential decay of the temporal frequency spectrum of these modes in the simulations indicate such flows possess a low-order chaotic character. In this paper, the spectral collocation methods used in this study are described, select axisymmetric simulations are reviewed, and initial results from three-dimensional unsteady simulations are presented. RP STREETT, CL (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 38 TC 31 Z9 31 U1 0 U2 2 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 1991 VL 7 IS 1 BP 41 EP 71 DI 10.1016/0168-9274(91)90103-7 PG 31 WC Mathematics, Applied SC Mathematics GA EV492 UT WOS:A1991EV49200004 ER PT J AU ERLEBACHER, G HUSSAINI, MY AF ERLEBACHER, G HUSSAINI, MY TI NONLINEAR EVOLUTION OF A 2ND-MODE WAVE IN SUPERSONIC BOUNDARY-LAYERS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article AB The nonlinear time evolution of a second-mode instability in a Mach 4.5 wall-bounded flow is computed by solving the full compressible, time-dependent Navier-Stokes equations. High accuracy is achieved by using a Fourier-Chebyshev collocation algorithm. Primarily inviscid in nature, second modes are characterized by high frequency and high growth rates compared to first modes. Time evolution of growth rate as a function of distance from the plate suggests this problem is amenable to the Stuart-Watson perturbation theory as generalized by Herbert. RP ERLEBACHER, G (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 25 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JAN PY 1991 VL 7 IS 1 BP 73 EP 91 DI 10.1016/0168-9274(91)90104-8 PG 19 WC Mathematics, Applied SC Mathematics GA EV492 UT WOS:A1991EV49200005 ER PT J AU MACARAEG, MG STREETT, CL AF MACARAEG, MG STREETT, CL TI LINEAR-STABILITY OF HIGH-SPEED MIXING LAYERS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article AB A newly developed spectral compressible linear stability code (SPECLS) is presented for analysis of shear flow stability and applied to high-speed boundary layers and free shear flows. The formulation utilizes the first application of a staggered mesh for a compressible flow analysis by a spectral technique and a multi-domain spectral discretization (MDSPD) option to resolve highly irregular structures. An order of magnitude less number of points is needed for equivalent accuracy in disturbance growth rates compared to calculations by a finite difference formulation, and a factor of three fewer points is required by the MDSPD relative to a single-domain spectral discretization (SPSPD). The mean flow in this study consists of two parallel gases, one of which is quiescent. A sudden appearance of multiple supersonic modes is found to occur near Mach 3. Their existence has not been observed in past studies. This occurrence is attributed to the boundary conditions which impose zero perturbations (reflecting boundary conditions) of all disturbances in the far field. The condition is imposed sufficiently far that subsonic disturbances are unaffected (i.e., results match the case of an unbounded free shear layer). However, at approximately Mach 2 there are radiating solution (supersonic disturbances) both above and below the shear region. The imposed "wall" far-field condition causes a multiplicity of higher supersonic modes at Mach numbers exceeding two. The issue of relevance in studying the stability of a free shear flow is the impact of transition on fuel-air mixing efficiency in scramjet combustors. The bounded free shear layer in this study is the proper analogue of this situation. In particular the observation of a pronounced drop in mixing efficiency as Mach number is increased may be related to these multiple modes which have very low growth rates relative to the subsonic disturbances which predominate at low Mach numbers. At M-infinity = 3 it is found that increasing the temperature of the quiescent gas relative to the injected gas in the mixing layer inhibits the development of these supersonic modes for low stremwise wave numbers. Verification of the method will be given for the case of boundary layers using an existing finite difference compressible stability code, and by comparison with analytical results obtained for free shear flows. RP MACARAEG, MG (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 17 TC 5 Z9 5 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 1991 VL 7 IS 1 BP 93 EP 127 DI 10.1016/0168-9274(91)90105-9 PG 35 WC Mathematics, Applied SC Mathematics GA EV492 UT WOS:A1991EV49200006 ER PT J AU LEE, WS OUTLAW, RA HOFLUND, GB DAVIDSON, MR AF LEE, WS OUTLAW, RA HOFLUND, GB DAVIDSON, MR TI AUGER-ELECTRON INTENSITY VARIATIONS IN OXYGEN-CHARGED SILVER SO APPLIED SURFACE SCIENCE LA English DT Article ID X-RAY PHOTOELECTRON; SURFACE-STRUCTURE DETERMINATION; MULTIPLE-SCATTERING; DIFFRACTION; EMISSION; ENERGY; RELAXATION; PHOTOEMISSION; CHEMISORPTION; SPECTROSCOPY AB Auger intensity variations over an oxygen-charged polycrystalline silver surface have been observed by studies of Auger images and line scans of selected adjacent grains which were determined to be the (421) and (221) orientations. The observed contrast (M4.5 VV transition) between the grains is produced by the variation in the detected Auger electrons caused by the different directions (interatomic direction) of forward focusing in each grain. The contrast produced by the Ag Auger electrons was found to be strongly dependent on the surface order of the grains, but that of the O Auger electrons was not, presumably becuase the atoms were dependent on the surface order of the grains, but that of the O Auger electrons was not, presumably because the atoms were randomly distributed throughout the Ag surface or subsurface. The contrast observed between the grains at the lower Auger energies (N1VV and N1N2.3V transitions) appeared to be produced by constructive interference from multiple scattering. The N1N2.3V electrons at 29 eV, for example, gave higher contrast than that of the N1VV transition at 78 eV. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV FLORIDA,GAINESVILLE,FL 32611. RP LEE, WS (reprint author), HAMPTON UNIV,DEPT PHYS,HAMPTON,VA 23668, USA. RI Davidson, Mark/C-1135-2009 NR 36 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JAN PY 1991 VL 47 IS 1 BP 91 EP 98 DI 10.1016/0169-4332(91)90105-S PG 8 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA EY465 UT WOS:A1991EY46500010 ER PT J AU STANLOTTER, H BOWMAN, EJ HOCHSTEIN, LI AF STANLOTTER, H BOWMAN, EJ HOCHSTEIN, LI TI RELATIONSHIP OF THE MEMBRANE ATPASE FROM HALOBACTERIUM-SACCHAROVORUM TO VACUOLAR ATPASES SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Article ID ARCHAEBACTERIUM SULFOLOBUS-ACIDOCALDARIUS; H+-ATPASE; ADENOSINE-TRIPHOSPHATASE; BOUND ATPASE; ACIDOTHERMOPHILIC ARCHAEBACTERIUM; METHANOSARCINA-BARKERI; CATALYTIC SUBUNIT; ALPHA-SUBUNIT; BETA-SUBUNIT; PURIFICATION C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF SANTA CRUZ,SINSHEIMER LABS,DEPT BIOL,SANTA CRUZ,CA 95064. FU NIGMS NIH HHS [GM-28703] NR 36 TC 17 Z9 18 U1 2 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-9861 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD JAN PY 1991 VL 284 IS 1 BP 116 EP 119 DI 10.1016/0003-9861(91)90272-K PG 4 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ER531 UT WOS:A1991ER53100020 PM 1824911 ER PT J AU WEEKS, WF WELLER, G CARSEY, FD AF WEEKS, WF WELLER, G CARSEY, FD TI THE POLAR OCEANS PROGRAM OF THE ALASKA SAR FACILITY SO ARCTIC LA English DT Article DE SAR; RADAR; SEA ICE; IMAGE ANALYSIS; REMOTE SENSING ID SEA ICE MOTION; SYNTHETIC APERTURE RADAR; NESTED CORRELATIONS; INTERNAL WAVES; TRACKING; CALIFORNIA; IMAGERY; MODEL AB The science plan for the Alaska SAR Facility (ASF) focuses on earth surface characteristics that are of interest within the overall concept of global change and that show significant regional, seasonal and interannual variations resulting in changes in the strength of their radar returns. The polar oceans, with the continuous motion and deformation of the pack ice and the changes in the surface state of the surrounding open seas, offer excellent opportunities for such research. Because such studies require both frequent and detailed analysis of Synthetic Aperture Radar (SAR) data, a Geophysical Processor System (GPS) has been developed to speed the extraction of useful geophysical information from SAR data sets. This system will initially produce three main types of products: a) sets of ice motion vectors obtained by automated computer tracking of identifiable ice floes on sequential images, b) the areal extent and location of several different ice types and open water and c) a characterization of the wave state in ice-free regions as well as within the ice in the marginal ice zone at locations where significant wave penetration occurs. Details of these analysis procedures are described. Initially the GPS is planned to process 10 image pairs/day for ice motion, 20 images/day for ice type variations and 1 image/day for wave information, with a total estimated processing time of 13 hours. A variety of projects plan to utilize the SAR data stream in studies of ice, lead and polynya dynamics and thermodynamics. A common feature of these research programs will be attempts to provide, via the coupling of the SAR data with ice property and ice dynamics models, improved estimates of the heat and mass fluxes into both the atmosphere and the ocean as affected by the characteristics of the ice cover. C1 JET PROP LAB MS-300-323,PASADENA,CA 91103. RP WEEKS, WF (reprint author), UNIV ALASKA FAIRBANKS,INST GEOPHYS,ALASKA SAR FACIL,FAIRBANKS,AK 99775, USA. NR 35 TC 2 Z9 2 U1 0 U2 0 PU ARCTIC INST N AMER PI CALGARY PA UNIV OF CALGARY 2500 UNIVERSITY DRIVE NW 11TH FLOOR LIBRARY TOWER, CALGARY AB T2N 1N4, CANADA SN 0004-0843 J9 ARCTIC JI Arctic PY 1991 VL 44 SU 1 BP 1 EP 10 PG 10 WC Environmental Sciences; Geography, Physical SC Environmental Sciences & Ecology; Physical Geography GA GV425 UT WOS:A1991GV42500003 ER PT J AU FOSTER, JL CHANG, ATC HALL, DK RANGO, A AF FOSTER, JL CHANG, ATC HALL, DK RANGO, A TI DERIVATION OF SNOW WATER EQUIVALENT IN BOREAL FORESTS USING MICROWAVE RADIOMETRY SO ARCTIC LA English DT Article DE BRIGHTNESS TEMPERATURE; BOREAL FOREST; MICROWAVES; RADIOMETER; SNOWPACK ID VEGETATION AB Efforts have been made by several investigators to produce a reliable global microwave snow algorithm to estimate snow depth or snow water equivalent (snow volume) and snow extent. Complications arise when trying to apply a global algorithm to specific regions where the climate, snowpack structure and vegetation vary. In forest regions, the microwave emission from dense coniferous forests may overwhelm the emission from the underlying snow-covered ground. As a result, algorithms employing microwave data tend to underestimate snow depths. Preliminary results indicate that the amount of underestimation can be minimized when the fraction of forest cover can be accounted for and used as an additional input in microwave algorithms. In the boreal forest of Saskatchewan, the standard error between the measured and the estimated snow water equivalent was reduced from 2.7 to 2.1 cm by using a generalized snow retrieval algorithm that includes the percentage of forest cover. However, perhaps as much as 25% of the boreal forest of North America and Eurasia is too dense to enable satisfactory snow water equivalent determinations to be made using passive microwave techniques alone. C1 USDA,BELTSVILLE AGR RES CTR E,AGR RES CTR,HYDROL LAB,BELTSVILLE,MD 20705. RP FOSTER, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH CODE 974,GREENBELT,MD 20771, USA. RI Hall, Dorothy/D-5562-2012 NR 27 TC 39 Z9 44 U1 1 U2 3 PU ARCTIC INST N AMER PI CALGARY PA UNIV OF CALGARY 2500 UNIVERSITY DRIVE NW 11TH FLOOR LIBRARY TOWER, CALGARY AB T2N 1N4, CANADA SN 0004-0843 J9 ARCTIC JI Arctic PY 1991 VL 44 SU 1 BP 147 EP 152 PG 6 WC Environmental Sciences; Geography, Physical SC Environmental Sciences & Ecology; Physical Geography GA GV425 UT WOS:A1991GV42500021 ER PT J AU SCHAEFER, BE FRIED, RE AF SCHAEFER, BE FRIED, RE TI RW-PER - NODAL MOTION CHANGES ITS AMPLITUDE BY 1.4 MAG SO ASTRONOMICAL JOURNAL LA English DT Article ID ECLIPSING BINARIES; PHOTOMETRY; STARS AB RW Per was found to have large secular changes in its eclipse amplitude. In blue light for example, the amplitude was 3.2 mag in the early 1900's, 2.2 mag in the late 1960's, and 1.75 mag in 1990. Throughout this time, the brightness at maximum was constant in all colors. We show that the only possible explanation is nodal motion, where the inclination varies with a period of roughly 10(5) yr. The nodal motion is caused by a third star, for which the light curve, the colors, and the O-C curve already provides evidence. Thus, RW Per is only the fourth known star with large changes of eclipse amplitude and is only the second example of nodal motion. C1 BRAESIDE OBSERV,FLAGSTAFF,AZ 86002. KITT PEAK NATL OBSERV,TUCSON,AZ 85726. UNIV SPACE RES ASSOC,WASHINGTON,DC. RP SCHAEFER, BE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 661,GREENBELT,MD 20771, USA. NR 28 TC 13 Z9 13 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 1991 VL 101 IS 1 BP 208 EP 213 DI 10.1086/115680 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP496 UT WOS:A1991EP49600019 ER PT J AU BROOKE, TY TOKUNAGA, AT KNACKE, RF AF BROOKE, TY TOKUNAGA, AT KNACKE, RF TI DETECTION OF THE 3.4 MU-M EMISSION FEATURE IN COMETS P/BRORSEN-METCALF AND OKAZAKI-LEVY-RUDENKO (1989R) AND AN OBSERVATIONAL SUMMARY SO ASTRONOMICAL JOURNAL LA English DT Article ID ARAKI-ALCOCK 1983D; ORGANIC GRAINS; IUE OBSERVATIONS; WEST 1975N; HALLEY; P/HALLEY; SPECTROSCOPY; EVOLUTION; SPECTRUM; WILSON AB The 3.4-mu-m emission feature due to cometary organics was detected in comets P/Brorsen-Metcalf and Okazaki-Levy Rudenko (1989r). Feature-to-continuum ratios in these two comets were higher than those expected from the trend seen in other comets to date. Three micron spectra of eight comets are reviewed. The 3.4-mu-m band flux is better correlated with the water production rate than with the dust production rate in this sample of comets. High feature-to-continuum ratios in P/Brorsen-Metcalf and Okazaki-Levy-Rudenko can be explained by the low dust-to-gas ratios of these two comets. The observations to date are consistent with cometary organics being present in all comets (even those for which no 3.4-mu-m feature was evident) at comparable abundances with respect to water. The emission mechanism and absolute abundance of the organics are not well determined; either gas-phase fluorescence or thermal emission from hot grains is consistent with the heliocentric distance dependence of the 3.4-mu-m band flux. There is an overall similarity in the spectral profiles of the 3.4-mu-m feature in comets; however, there are some potentially significant differences in the details of the spectra. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP BROOKE, TY (reprint author), UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822, USA. NR 31 TC 32 Z9 32 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 1991 VL 101 IS 1 BP 268 EP 278 DI 10.1086/115686 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EP496 UT WOS:A1991EP49600025 ER PT J AU WILLIAMS, JG NEWHALL, XX DICKEY, JO AF WILLIAMS, JG NEWHALL, XX DICKEY, JO TI LUNI-SOLAR PRECESSION - DETERMINATION FROM LUNAR LASER RANGES SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE PRECESSION; NUTATION; ASTRONOMICAL CONSTANTS ID FORCED NUTATIONS; RADIO INTERFEROMETRY; RIGID-EARTH; EXPRESSIONS; QUANTITIES; CONSTANTS; ROTATION; GEODESY AB Two decades of lunar laser ranges have been analyzed to determine corrections to the Earth's luni-solar precession constant and 18.6 yr nutation coefficients. The correction to the IAU-adopted precession constant is -2.7 +/- 0.4 milliarcseconds/yr (mas/yr), giving the luni-solar precession constant as 50.3851 "/yr at J2000. The 18.6 yr nutation of the pole is found to be 3.0 +/- 1.5 mas larger in magnitude than the 1980 IAU series. The correction to the annual term, previously discovered by VLBI, is found to be 1.8 +/- 0.5 mas if assumed to be a circular correction to the nutation of the pole. RP WILLIAMS, JG (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 23 TC 35 Z9 35 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 PY 1991 VL 241 IS 1 BP L9 EP L12 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET955 UT WOS:A1991ET95500003 ER PT J AU DAPERGOLAS, A KONTIZAS, E KONTIZAS, M PASIAN, F PUCILLO, M SANTIN, P AF DAPERGOLAS, A KONTIZAS, E KONTIZAS, M PASIAN, F PUCILLO, M SANTIN, P TI SPECTRAL TYPES OF STARS IN THE SMC ASSOCIATIONS NGC-456, NGC460A, B AND NGC465 SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE GALAXIES; MAGELLARRIC CLOUDS; CLUSTERS; OPEN AND ASSOCIATIONS; STARS; CLASSIFICATIONS AB Spectral types of stars for an extended area (1200 arcmin2) of the SMC, containing the associations NGC456, NGC460 a, b and NGC465 have been derived here. High quality UJ and YJ film copies of objective prism plates taken with the 1.2m U.K. schmidt telescope were used. The medium dispersion spectral (830 angstrom/mm) were digitized with a PDS microdensitometer and spectra types of stars were obtained down to approximately 16.5mag. A computer interactive method of reduction has been developed and the spectral types obtained are accurate to 0.3 spectral subtypes. Spectral classification for the low (2440 angstrom/mm) dispersion spectra down to 18.5mag was carried out visually using a binocular microscope. The frequency distribution of stars in the associations region after subtracting the field stars, has revealed that only blue main sequence stars are their members. C1 NASA,GODDARD SPACE FLIGHT CTR,LASP,GREENBELT,MD 20771. NATL OBSERV,INST ASTRON,GR-11810 ATHENS,GREECE. OSSERVATORIO ASTRONO TRIESTE,I-34131 TRIESET,ITALY. EUROPEAN SO OBSERV,ST ECF,W-8046 GARCHING,GERMANY. RI Dapergolas, Anastasios/L-4954-2013; Kontizas, Evangelos/A-1969-2014 NR 12 TC 6 Z9 6 U1 0 U2 0 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 1991 VL 87 IS 1 BP 97 EP 108 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EQ390 UT WOS:A1991EQ39000007 ER PT J AU HINTZEN, P ROMANISHIN, W VALDES, F AF HINTZEN, P ROMANISHIN, W VALDES, F TI GALAXIES CLUSTERING AROUND QSOS WITH Z=0.9-1.5 AND THE ORIGIN OF BLUE FIELD GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article ID SPECTRAL EVOLUTION; REDSHIFT QUASARS; PHOTOMETRY; LUMINOSITY; ASSOCIATION; STANDARDS; CATALOG; STARS C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV OKLAHOMA,DEPT PHYS & ASTRON,NORMAN,OK 73019. NATL OPT ASTRON OBSERV,TUCSON,AZ. RP HINTZEN, P (reprint author), UNIV NEVADA,DEPT PHYS,LAS VEGAS,NV 89154, USA. NR 29 TC 63 Z9 63 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1991 VL 366 IS 1 BP 7 EP & DI 10.1086/169534 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400002 ER PT J AU CLAVEL, J REICHERT, GA ALLOIN, D CRENSHAW, DM KRISS, G KROLIK, JH MALKAN, MA NETZER, H PETERSON, BM WAMSTEKER, W ALTAMORE, A BARIBAUD, T BARR, P BECK, S BINETTE, L BROMAGE, GE BROSCH, N DIAZ, AI FILIPPENKO, AV FRICKE, K GASKELL, CM GIOMMI, P GLASS, IS GONDHALEKAR, P HACKNEY, RL HALPERN, JP HUTTER, DJ JORSATER, S KINNEY, AL KOLLATSCHNY, W KORATKAR, A KORISTA, KT LAOR, A LASOTA, JP LEIBOWITZ, E MAOZ, D MARTIN, PG MAZEH, T MEURS, EJA NAIR, AD OBRIEN, P PELAT, D PEREZ, E PEROLA, GC PTAK, RL RODRIGUEZPASCUAL, P ROSENBLATT, EI SADUN, AC SANTOSLLEO, M SHAW, RA SMITH, PS STIRPE, GM STONER, R SUN, WH ULRICH, MH VANGRONINGEN, E ZHENG, W AF CLAVEL, J REICHERT, GA ALLOIN, D CRENSHAW, DM KRISS, G KROLIK, JH MALKAN, MA NETZER, H PETERSON, BM WAMSTEKER, W ALTAMORE, A BARIBAUD, T BARR, P BECK, S BINETTE, L BROMAGE, GE BROSCH, N DIAZ, AI FILIPPENKO, AV FRICKE, K GASKELL, CM GIOMMI, P GLASS, IS GONDHALEKAR, P HACKNEY, RL HALPERN, JP HUTTER, DJ JORSATER, S KINNEY, AL KOLLATSCHNY, W KORATKAR, A KORISTA, KT LAOR, A LASOTA, JP LEIBOWITZ, E MAOZ, D MARTIN, PG MAZEH, T MEURS, EJA NAIR, AD OBRIEN, P PELAT, D PEREZ, E PEROLA, GC PTAK, RL RODRIGUEZPASCUAL, P ROSENBLATT, EI SADUN, AC SANTOSLLEO, M SHAW, RA SMITH, PS STIRPE, GM STONER, R SUN, WH ULRICH, MH VANGRONINGEN, E ZHENG, W TI STEPS TOWARD DETERMINATION OF THE SIZE AND STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI .1. AN 8 MONTH CAMPAIGN OF MONITORING NGC-5548 WITH IUE SO ASTROPHYSICAL JOURNAL LA English DT Article ID ULTRAVIOLET EXPLORER IUE; SEYFERT-GALAXIES; EMISSION-LINES; VARIABILITY; NGC-4151; QUASARS; FEATURES; GAS; AGN C1 COMP SCI CORP,GODDARD SPACE FLIGHT CTR,ASTRON PROGRAM,GREENBELT,MD 20771. OBSERV PARIS,F-92195 MEUDON,FRANCE. JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. TEL AVIV UNIV,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. TEL AVIV UNIV,WISE OBSERV,IL-69978 TEL AVIV,ISRAEL. OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. UNIV ROME,IST ASTRON,I-00161 ROME,ITALY. EUROPEAN SPACE AGCY,EUROPEAN SPACE & TECHNOL CTR,EXOSAT OBSERV,DIV ASTROPHYS,2200 AG NOORDWIJK,NETHERLANDS. UNIV TORONTO,MCLENNAN LABS,CITA,TORONTO M5S 1A1,ONTARIO,CANADA. RUTHERFORD APPLETON LAB,ASTROPHYS GRP,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV AUTONOMA MADRID,DEPT FIS TEOR,E-28049 MADRID,SPAIN. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV STERNWARTE GOTTINGEN,W-3400 GOTTINGEN,GERMANY. UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. S AFRICAN ASTRON OBSERV,CAPE TOWN 7935,SOUTH AFRICA. WESTERN KENTUCKY UNIV,DEPT PHYS & ASTRON,BOWLING GREEN,KY 42101. COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. EUROPEAN SPACE AGCY,SPACE TELESCOPE EUROPEAN COORDINATING FACIL,W-8046 GARCHING,GERMANY. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. MAX PLANCK INST EXTRATERR PHYS,W-80416 GARCHING,GERMANY. BOWLING GREEN STATE UNIV,DEPT PHYS & ASTRON,BOWLING GREEN,OH 43403. UNIV LONDON UNIV COLL,DEPT ASTRON,LONDON WC1E 6BT,ENGLAND. INST ASTROFIS CANARIAS,E-38200 LA LAGUNA,SPAIN. UNIV COMPLUTENSE MADRID,INST ASTRON,E-28040 MADRID 3,SPAIN. UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI,LA JOLLA,CA 92093. AGNES SCOTT COLL,BRADLEY OBSERV,DECATUR,GA 30030. UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. OBSERVATORIO ASTRON BOLOGNA,I-40126 BOLOGNA,ITALY. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. EUROPEAN SO OBSERV,W-8046 GARCHING,GERMANY. UPPSALA ASTRON OBSERV,S-75120 UPPSALA,SWEDEN. UNIV ALABAMA,DEPT PHYS & ASTRON,TUSCALOOSA,AL 35487. RP CLAVEL, J (reprint author), EUROPEAN SPACE AGCY,IUE OBSERV,POB 50727,E-28080 MADRID,SPAIN. RI Brosch, Noah/C-7889-2009; Stirpe, Giovanna/O-9393-2015; OI Stirpe, Giovanna/0000-0002-3702-8731; giommi, paolo/0000-0002-2265-5003; Gaskell, C/0000-0003-4888-2009; Perez, Enrique/0000-0001-9737-4559 NR 51 TC 387 Z9 387 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 1991 VL 366 IS 1 BP 64 EP 81 DI 10.1086/169540 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400008 ER PT J AU JOY, M HARVEY, PM TOLLESTRUP, EV SELLGREN, K MCGREGOR, PJ HYLAND, AR AF JOY, M HARVEY, PM TOLLESTRUP, EV SELLGREN, K MCGREGOR, PJ HYLAND, AR TI AN INFRARED JET IN CENTAURUS-A - A LINK TO THE EXTRANUCLEAR ACTIVITY IN DISTANT RADIO GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article ID EMISSION; NGC-5128; REDSHIFT; ALIGNMENT; CONTINUUM; FILAMENTS; NUCLEUS; ORIGIN; AXES C1 UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. AUSTRALIAN NATL UNIV, MT STROMLO & SIDING SPRING OBSERV, AUSTRALIAN NATL OBSERV, WODEN, ACT 2606, AUSTRALIA. UNIV TEXAS, DEPT ASTRON, AUSTIN, TX 78712 USA. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, ES 65, HUNTSVILLE, AL 35812 USA. NR 31 TC 19 Z9 19 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 1991 VL 366 IS 1 BP 82 EP + DI 10.1086/169541 PN 1 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400009 ER PT J AU SODROSKI, TJ AF SODROSKI, TJ TI THE PHYSICAL-PROPERTIES OF GIANT MOLECULAR CLOUD COMPLEXES IN THE OUTER GALAXY - IMPLICATIONS FOR THE RATIO OF H2 COLUMN DENSITY TO (CO)-C-12 INTENSITY SO ASTROPHYSICAL JOURNAL LA English DT Article ID 1ST GALACTIC QUADRANT; CARBON-MONOXIDE; CO SURVEY; STAR FORMATION; SOLAR CIRCLE; INNER GALAXY; DARK CLOUDS; GAMMA-RAYS; MILKY-WAY; GAS RP SODROSKI, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 685,GREENBELT,MD 20771, USA. NR 55 TC 57 Z9 57 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 1991 VL 366 IS 1 BP 95 EP 106 DI 10.1086/169543 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400011 ER PT J AU COLGAN, SWJ SIMPSON, JP RUBIN, RH ERICKSON, EF HAAS, MR WOLF, J AF COLGAN, SWJ SIMPSON, JP RUBIN, RH ERICKSON, EF HAAS, MR WOLF, J TI FAR-INFRARED LINES FROM G45.13+0.14-A AND K3-50-A - DENSITY-FLUCTUATIONS IN COMPACT H-II REGIONS SO ASTROPHYSICAL JOURNAL LA English DT Article ID FORBIDDEN LINES; ORION NEBULA; ABUNDANCE GRADIENT; OPTICAL-PROPERTIES; SILICATE GRAINS; RADIO-SOURCES; HII-REGIONS; O-III; MODELS; DUST C1 UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. MAX PLANCK INST ASTRON,W-6900 HEIDELBERG,GERMANY. RP COLGAN, SWJ (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-6,MOFFETT FIELD,CA 94035, USA. RI Colgan, Sean/M-4742-2014 NR 67 TC 16 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 1991 VL 366 IS 1 BP 172 EP 180 DI 10.1086/169549 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400017 ER PT J AU LADD, EF ADAMS, FC CASEY, S DAVIDSON, JA FULLER, GA HARPER, DA MYERS, PC PADMAN, R AF LADD, EF ADAMS, FC CASEY, S DAVIDSON, JA FULLER, GA HARPER, DA MYERS, PC PADMAN, R TI FAR-INFRARED AND SUBMILLIMETER-WAVELENGTH OBSERVATIONS OF STAR-FORMING DENSE CORES .1. SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article ID MOLECULAR CLOUD CORES; LOW-MASS STARS; H-II REGIONS; DARK CLOUDS; RADIATIVE-TRANSFER; NH3 OBSERVATIONS; CO OBSERVATIONS; PROTOSTARS; EMISSION; OUTFLOWS C1 UNIV CHICAGO,YERKES OBSERV,CHICAGO,IL 60637. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CAMBRIDGE,CAMBRIDGE,ENGLAND. RP LADD, EF (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,MS-51,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 64 TC 69 Z9 69 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 1991 VL 366 IS 1 BP 203 EP 220 DI 10.1086/169553 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400021 ER PT J AU PARMAR, AN SMALE, AP VERBUNT, F CORBET, RHD AF PARMAR, AN SMALE, AP VERBUNT, F CORBET, RHD TI THE ORBITAL EPHEMERIS AND ECLIPSE TRANSITIONS OF THE LOW-MASS X-RAY BINARY EXO-0748-676 SO ASTROPHYSICAL JOURNAL LA English DT Article ID EXO 0748-676; CLOSE BINARIES; CYGNUS-X-3; EVOLUTION; GINGA; HERCULES-X-1; MODULATION; DISCOVERY; BEHAVIOR; LIGHT C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. UNIV UTRECHT,INST ASTRON,UTRECHT,NETHERLANDS. INST SPACE & ASTRONAUT SCI,TOKYO,JAPAN. RP PARMAR, AN (reprint author), EUROPEAN SPACE AGCY,EUROPEAN SPACE TECHNOL CTR,EXOSAT OBSERV,DEPT SPACE SCI,2200 AG NOORDWIJK,NETHERLANDS. NR 38 TC 31 Z9 31 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1991 VL 366 IS 1 BP 253 EP 260 DI 10.1086/169557 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400025 ER PT J AU CORCORAN, MF AF CORCORAN, MF TI CIRCUMSTELLAR MATERIAL AROUND THE MASSIVE CLOSE BINARY DH CEPHEI SO ASTROPHYSICAL JOURNAL LA English DT Article ID O-TYPE STARS; RADIATION-DRIVEN WINDS; ULTRAVIOLET SPECTRAL MORPHOLOGY; THIN STELLAR ENVELOPES; WAVELENGTH DEPENDENCE; LINEAR-POLARIZATION; THOMSON SCATTERING; LOSS RATES; EXTINCTION; MODELS RP CORCORAN, MF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,NATL RES COUNCIL,NAS,GREENBELT,MD 20771, USA. NR 52 TC 7 Z9 7 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 1991 VL 366 IS 1 BP 308 EP 317 DI 10.1086/169563 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN154 UT WOS:A1991EN15400031 ER PT J AU BURATTI, BJ DUNBAR, RS AF BURATTI, BJ DUNBAR, RS TI OBSERVATION OF A RAPID DECREASE IN THE BRIGHTNESS OF THE COMA OF 2060-CHIRON IN 1990 JANUARY SO ASTROPHYSICAL JOURNAL LA English DT Article ID CHIRON C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP BURATTI, BJ (reprint author), CALTECH,PALOMAR OBSERV,MAIL STOP 183-501,PASADENA,CA 91125, USA. NR 14 TC 12 Z9 12 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 1991 VL 366 IS 1 BP L47 EP L49 DI 10.1086/185906 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN155 UT WOS:A1991EN15500011 ER PT J AU SCHAEFER, BE AF SCHAEFER, BE TI FLARES ON MIRA STARS SO ASTROPHYSICAL JOURNAL LA English DT Article ID GAMMA-RAY BURSTS; FLASHES C1 UNIV SPACE RES ASSOC,COLUMBIA,MD 21044. RP SCHAEFER, BE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 661,GREENBELT,MD 20771, USA. NR 45 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1991 VL 366 IS 1 BP L39 EP L42 DI 10.1086/185904 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EN155 UT WOS:A1991EN15500009 ER PT J AU THOMPSON, AM HUNTLEY, MA STEWART, RW AF THOMPSON, AM HUNTLEY, MA STEWART, RW TI PERTURBATIONS TO TROPOSPHERIC OXIDANTS, 1985-2035 .2. CALCULATIONS OF HYDROGEN-PEROXIDE IN CHEMICALLY COHERENT REGIONS SO ATMOSPHERIC ENVIRONMENT PART A-GENERAL TOPICS LA English DT Article; Proceedings Paper CT INTERNATIONAL CONF ON GENERATION OF OXIDANTS ON REGIONAL AND GLOBAL SCALES CY JUL 03-07, 1989 CL UNIV E ANGLIA, NORWICH, ENGLAND SP UK DEPT ENVIRONM, BRIT PETR HO UNIV E ANGLIA DE HYDROGEN PEROXIDE; OXIDANTS; OXIDIZING CAPACITY ID UNITED-STATES; SURFACE OZONE; DISTRIBUTIONS AB Increasing global emissions of trace gases NO, CH4, and CO, along with perturbations initiated by changes in stratospheric O3 and H2O, may cause tropospheric hydrogen peroxide (H2O2) levels to change. Specific scenarios of CH4-CO-NO emissions and global climate changes are used to predict HO2 and H2O2 changes from 1985 to 2035 in a one-dimensional model that simulates different chemically coherent regions (e.g. urban, non-urban continental and marine mid-lattitudes; marine and continental low latitudes). If CH4 and CO emissions continue to increase throughout the troposphere at current rates (1% yr-1), there will be large increases in H2O2, for example, more than 100% in the urban boundary layer from 1985 to 2035. Globally, H2O2 will increase 22% with HO2 increasing 8% and O3 increasing 13%. When CH4, CO and NO emissions are specified on a regionally varying basis and are parameterized for high and low potential growth rates, globally averaged increases in surface concentrations are 12% for H2O2 and 18% for O3. A global warming (with increased H2O vapor) or stratospheric O3 depletion superimposed on CH4, CO and NO emissions changes will cut O3 increases but add to peroxide, increasing levels as much as 150% above present day in some regions. Both globally uniform and region-specific scenarios predict a 10-15% loss in global OH from 1985 to 2035. Thus, conversion of OH to HO2 and H2O2 in the atmosphere may signify a loss of gaseous oxidizing capacity in the atmosphere and an increase in aqueous-phase oxidizing capacity. C1 APPL RES CORP,LANDOVER,MD 20785. RP THOMPSON, AM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 22 TC 17 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0004-6981 J9 ATMOS ENVIRON A-GEN PY 1991 VL 25 IS 9 BP 1837 EP 1850 DI 10.1016/0960-1686(91)90267-B PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA FV359 UT WOS:A1991FV35900011 ER PT J AU SEELY, JF BROWN, CM FELDMAN, U EKBERG, JO KEANE, CJ MACGOWAN, BJ KANIA, DR BEHRING, WE AF SEELY, JF BROWN, CM FELDMAN, U EKBERG, JO KEANE, CJ MACGOWAN, BJ KANIA, DR BEHRING, WE TI WAVELENGTHS AND ENERGY-LEVELS FOR THE NA-I ISOELECTRONIC SEQUENCE Y28+ THROUGH U81+ SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID TRANSITIONS; IONS; SPECTRA; MOLYBDENUM C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,SOLAR PHYS BRANCH,GREENBELT,MD 20771. UNIV LUND,DEPT PHYS,S-22101 LUND,SWEDEN. RP SEELY, JF (reprint author), USN,RES LAB,EO HULBURT CTR SPACE RES,WASHINGTON,DC 20375, USA. NR 15 TC 34 Z9 34 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD JAN PY 1991 VL 47 IS 1 BP 1 EP 15 DI 10.1016/0092-640X(91)90016-W PG 15 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA EX553 UT WOS:A1991EX55300001 ER PT J AU MATSON, PA VOLKMANN, C COPPINGER, K REINERS, WA AF MATSON, PA VOLKMANN, C COPPINGER, K REINERS, WA TI ANNUAL NITROUS-OXIDE FLUX AND SOIL-NITROGEN CHARACTERISTICS IN SAGEBRUSH STEPPE ECOSYSTEMS SO BIOGEOCHEMISTRY LA English DT Article DE NITROUS OXIDE; NITRIFICATION; NITROGEN MINERALIZATION; REGIONAL ESTIMATES; SAGEBRUSH STEPPE; SOIL NITROGEN ID VEGETATION; EMISSIONS; FOREST AB Soil nitrogen transformations and nitrous oxide fluxes were measured in a range of sagebrush steppe ecosystems in south-central Wyoming. Net nitrate production, measured in laboratory incubations, was highest in the ecosystem type dominated by Artemisia tridentata ssp. vaseyana, especially early in the growing season. Fluxes of nitrous oxide, measured in closed chambers and analyzed by gas chromatography, also tended to be higher in the same type, but only for short periods in the spring. Thereafter, all nitrous oxide fluxes were low and did not differ consistently among types. Estimated average annual fluxes for three Artemisia ecosystem types (dominated by Artemisia tridentata ssp. vaseyana, Artemisia tridentata ssp. wyomingensis, and Artemisia nova) were 0.32, 0.23 and 0.13 kg N2O-N ha-1y-1 respectively. Average annual flux, weighted by the areal extent of these and other vegetation types in the region, was approximately 0.21 kg N2O-N ha-1y-1. Assuming this landscape is representative of sagebrush steppe, we calculate a flux of 9.5 x 10(9) g y-1 of N2O-N from U.S. sagebrush steppe, and a flux of 1.1 x 10(11) g y-1 of N2O-N from analogous desert and semi-desert shrublands of the world. C1 UNIV WYOMING,DEPT BOT,LARAMIE,WY 82071. RP MATSON, PA (reprint author), NASA,AMES RES CTR,ECOSYST SCI & TECHNOL BRANCH,MOFFETT FIELD,CA 94035, USA. NR 21 TC 36 Z9 40 U1 2 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0168-2563 J9 BIOGEOCHEMISTRY JI Biogeochemistry PY 1991 VL 14 IS 1 BP 1 EP 12 PG 12 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA GV886 UT WOS:A1991GV88600001 ER PT J AU ZAK, M AF ZAK, M TI NEURODYNAMICS WITH SPATIAL SELF-ORGANIZATIONS SO BIOLOGICAL CYBERNETICS LA English DT Article ID FIELD AB A neural network architecture with self-organization in phase and actual space is proposed and discussed. Special type of differential local interconnections simulating diffusion, dispersion, and convection were investigated. It is shown that these interconnections are responsible for biological pattern formation in a homogeneous neural structure. The model suggests a phenomenological explanation of the mechanisms of edge detection in vision process. RP ZAK, M (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 7 TC 3 Z9 3 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. PY 1991 VL 65 IS 2 BP 121 EP 127 DI 10.1007/BF00202387 PG 7 WC Computer Science, Cybernetics; Neurosciences SC Computer Science; Neurosciences & Neurology GA FW173 UT WOS:A1991FW17300006 PM 1912003 ER PT J AU ZAK, M AF ZAK, M TI TERMINAL CHAOS FOR INFORMATION-PROCESSING IN NEURODYNAMICS SO BIOLOGICAL CYBERNETICS LA English DT Article ID NEURAL NETWORKS; BRAIN FUNCTIONS; DYNAMICS AB New nonlinear phenomenon - terminal chaos caused by failure of the Lipschitz condition at equilibrium points of dynamical systems is introduced. It is shown that terminal chaos has a well organized probabilistic structure which can be predicted and controlled. This gives an opportunity to exploit this phenomenon for information processing. It appears that chaotic states of neurons activity are associated with higher level of cognitive processes such as generalization and abstraction. RP ZAK, M (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 21 Z9 21 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. PY 1991 VL 64 IS 4 BP 343 EP 351 DI 10.1007/BF00199599 PG 9 WC Computer Science, Cybernetics; Neurosciences SC Computer Science; Neurosciences & Neurology GA EW709 UT WOS:A1991EW70900011 PM 2025668 ER PT J AU ROTHSCHILD, LJ AF ROTHSCHILD, LJ TI A MODEL FOR DIURNAL PATTERNS OF CARBON FIXATION IN A PRECAMBRIAN MICROBIAL MAT BASED ON A MODERN ANALOG SO BIOSYSTEMS LA English DT Article; Proceedings Paper CT 8TH BIENNIAL CONF OF THE INTERNATIONAL SOC FOR EVOLUTIONARY PROTISTOLOGY CY JUN 27-JUL 01, 1990 CL UNIV MARYLAND, COLLEGE PARK, MD SP INT SOC EVOLUTIONARY PROTISTOL HO UNIV MARYLAND DE PHOTOSYNTHESIS; DIURNAL CYCLES; CARBON FIXATION; STROMATOLITES; MICROBIAL MATS; EVOLUTION; CYANOBACTERIA ID WESTERN-AUSTRALIA; EARLY EARTH; PHOTOSYNTHESIS; ATMOSPHERE AB Microbial mat communities are one of the first and most prevalent biological communities known from the Precambrian fossil record. These fossil mat communities are found as laminated sedimentary rock structures called stromatolites. Using a modern microbial mat as an analog for Precambrian stromatolites, a study of carbon fixation during a diurnal cycle under ambient conditions was undertaken. The rate of carbon fixation depends primarily on the availability of light (consistent with photosynthetic carbon fixation) and inorganic carbon, and not nitrogen or phosphorus. Atmospheric PCO2 is thought to have decreased from 10 bars at 4 Ga (10(9) years before present) to approximately 10(-4) bars today, implying a change in the availability of inorganic carbon for carbon fixation. Experimental manipulation of levels of inorganic carbon to levels that may have been available to Precambrian mat communities resulted in increased levels of carbon fixation during daylight hours. Combining these data with models of daylength during the Precambrian, models are derived for diurnal patterns of photosynthetic carbon fixation in a Precambrian microbial mat community. The models suggest that, even in the face of shorter daylengths during the Precambrian, total daily carbon fixation has been declining over geological time, with most of the decrease having occurred during the Precambrian. RP ROTHSCHILD, LJ (reprint author), NASA,AMES RES CTR,MAIL STOP 239-12,MOFFETT FIELD,CA 94035, USA. NR 21 TC 10 Z9 10 U1 1 U2 5 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 1991 VL 25 IS 1-2 BP 13 EP 23 DI 10.1016/0303-2647(91)90009-A PG 11 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA FP943 UT WOS:A1991FP94300002 PM 1854911 ER PT J AU ROSSOW, WB SCHIFFER, RA AF ROSSOW, WB SCHIFFER, RA TI ISCCP CLOUD DATA PRODUCTS SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CLIMATE-RESEARCH; DATA SET; SATELLITE; COVER; DISTRIBUTIONS; PARAMETERS; RADIATION AB The operational data collection phase of the International Satellite Cloud Climatology Project (ISCCP) began in July 1983. Since then, visible and infrared images from an international network of weather satellites have been routinely processed to produce a global cloud climatology. This report outlines the key steps in the data processing, describes the main features of the data products, and indicates how to obtain these data. We illustrate some early results of this analysis. C1 NASA,WASHINGTON,DC 20546. RP ROSSOW, WB (reprint author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA. RI Rossow, William/F-3138-2015 NR 49 TC 1030 Z9 1065 U1 1 U2 38 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 1991 VL 72 IS 1 BP 2 EP 20 DI 10.1175/1520-0477(1991)072<0002:ICDP>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EY148 UT WOS:A1991EY14800001 ER PT J AU FINGER, FG SCHMIDLIN, FJ AF FINGER, FG SCHMIDLIN, FJ TI UPPER-AIR MEASUREMENTS AND INSTRUMENTATION WORKSHOP SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB The tremendous interest in upper-air measurement quality by the meteorological community brought together experts from many agencies at a Workshop on Upper-Air Measurements and Instruments. The workshop was held at NASA's Wallops Island facility on 14-15 November 1989. The purpose of the workshop was to establish a forum for the interchange of information to discuss mutual problems and to provide a basis for future work. A major recommendation of the workshop was for the development of a reference radiosonde instrument. A description of the workshop highlights are presented. C1 NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. RP FINGER, FG (reprint author), SM SYST & RES CORP,LANDOVER,MD 20785, USA. NR 0 TC 7 Z9 7 U1 0 U2 0 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 1991 VL 72 IS 1 BP 50 EP 55 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EY148 UT WOS:A1991EY14800006 ER PT J AU GAIER, JR HAMBOURGER, PD SLABE, ME AF GAIER, JR HAMBOURGER, PD SLABE, ME TI RESISTIVITY OF PRISTINE AND INTERCALATED GRAPHITE FIBER EPOXY COMPOSITES SO CARBON LA English DT Article DE CARBON FIBERS; INTERCALATION; BROMINE; EPOXY COMPOSITES AB Laminar composites have been fabricated from pristine and bromine intercalated Amoco P-55, P-75, and P-100 graphite fibers and Hysol-Grafil EAG101-1 film epoxy. The thickness and rf eddy current resistivity of several samples were measured at grid points and averaged point by point to obtain final values. Although the values obtained this way have high precision (< 3% deviation), the resistivity values appear to be 20 to 90% higher than resistivities measured on high aspect ratio samples using multipoint techniques, and by those predicted by theory. The temperature dependence of the resistivity indicates that the fibers are neither damaged nor deintercalated by the composite fabrication process. The resistivity of the composites is a function of sample thickness (i.e., resin content). Composite resistivity is dominated by fiber resistivity, so lowering the resistivity of the fibers, either through increased graphitization or intercalation, results in a lower composite resistivity. A modification of the simple rule of mixtures model appears to predict the conductivity of high aspect ratio samples measured along a fiber direction, but a directional dependence appears which is not predicted by the theory. The resistivity of these materials is clearly more complex than that of homogeneous materials. C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44115. RP GAIER, JR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 6 Z9 6 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0008-6223 J9 CARBON JI Carbon PY 1991 VL 29 IS 3 BP 313 EP 320 DI 10.1016/0008-6223(91)90199-S PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA FA959 UT WOS:A1991FA95900004 ER PT J AU LEISIEUTRE, GA ECKEL, AJ DICARLO, JA AF LEISIEUTRE, GA ECKEL, AJ DICARLO, JA TI DAMPING OF BROMINE-INTERCALATED P-100 GRAPHITE FIBERS SO CARBON LA English DT Article DE GRAPHITE FIBERS; INTERCALATION; BROMINE; DAMPING AB A resonant flexural free decay test method was used to measure the damping of single pristine and bromine-intercalated P-100 graphite fibers in high vacuum, at temperatures from 77 K to 675 K, and at frequencies from 50 to 2000 hz. The damping capacity of the intercalated fibers was found to be significantly greater than that of the pristine fibers. For frequencies from 80 hz to 1300 hz, the pristine fibers exhibited two small peaks in damping capacity (approximately 0.2%) in the vicinity of 145 K and 230 K, while the intercalated fibers exhibited one large peak (approximately 3%) near 230 K. The activation energy of the mechanism underlying the 230 K damping peak in the intercalated fibers is 0.44 eV, suggesting an atomic process. The peak is unsymmetrical in (1/T) and, at half the peak damping, is four to five times wider than that of a standard anelastic solid, indicating a broad distribution of relaxation times. The specific physical mechanisms underlying the observed damping in both the pristine and intercalated fibers remain to be determined. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP LEISIEUTRE, GA (reprint author), PENN STATE UNIV,UNIVERSITY PK,PA 16802, USA. NR 11 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 0008-6223 J9 CARBON JI Carbon PY 1991 VL 29 IS 7 BP 1025 EP 1032 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA GF179 UT WOS:A1991GF17900028 ER PT J AU YUNG, CN DEWITT, KJ BROCKWELL, JL CHAI, AT AF YUNG, CN DEWITT, KJ BROCKWELL, JL CHAI, AT TI THE TRANSIENT MOTION OF A SPHERICAL FLUID DROPLET SO CHEMICAL ENGINEERING COMMUNICATIONS LA English DT Article DE FINITE DIFFERENCE; TRANSIENT; FLUID DROPLET; GAS BUBBLE; NAVIER-STOKES ID INTERNAL CIRCULATION; TERMINAL VELOCITY C1 UNIV TOLEDO,DEPT CHEM ENGN,TOLEDO,OH 43606. UNION CARBIDE CORP,S CHARLESTON,WV 25309. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 21 TC 1 Z9 1 U1 1 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0098-6445 J9 CHEM ENG COMMUN JI Chem. Eng. Commun. PY 1991 VL 110 BP 163 EP 186 DI 10.1080/00986449108939948 PG 24 WC Engineering, Chemical SC Engineering GA HC406 UT WOS:A1991HC40600010 ER PT J AU CHUNG, GY MCCOY, BJ SMITH, JM CAGLIOSTRO, DE CARSWELL, M AF CHUNG, GY MCCOY, BJ SMITH, JM CAGLIOSTRO, DE CARSWELL, M TI CHEMICAL VAPOR INFILTRATION - MODELING SOLID MATRIX DEPOSITION IN CERAMIC CERAMIC COMPOSITES SO CHEMICAL ENGINEERING SCIENCE LA English DT Article ID SILICON AB A model is developed to predict the effect of diffusion, the rate of deposition, and spatial distribution of a solid matrix in a woven fabric forming a ceramic-ceramic composite. To the knowledge of the authors there has been no prior treatment of chemical vapor infiltration in a system of plies consisting of an assembly of woven tows containing bundles of filaments. The model predicts the times to fill the gaps around the filaments of a tow, the space between plies, and the holes between the tows. It also predicts the porosity of the composite as a function of position and processing time. Predictions are made for an illustrative case of deposition of silicon carbide matrix within a carbon fabric. C1 UNIV CALIF DAVIS,DEPT CHEM ENGN,DAVIS,CA 95616. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 19 TC 22 Z9 22 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PY 1991 VL 46 IS 3 BP 723 EP 733 DI 10.1016/0009-2509(91)80178-2 PG 11 WC Engineering, Chemical SC Engineering GA EU986 UT WOS:A1991EU98600002 ER PT J AU GRUBBS, RB MARDER, SR PERRY, JW SCHAEFER, WP AF GRUBBS, RB MARDER, SR PERRY, JW SCHAEFER, WP TI 2ND-ORDER NONLINEARITIES AND CRYSTAL-STRUCTURE OF 2-METHOXY-4'-NITRO-(E)-STILBENE SO CHEMISTRY OF MATERIALS LA English DT Note ID 2ND-HARMONIC GENERATION; OPTICAL NONLINEARITIES; MOLECULAR-CRYSTALS C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. CALTECH, DIV CHEM & CHEM ENGN, PASADENA, CA 91125 USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 14 TC 12 Z9 13 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 EI 1520-5002 J9 CHEM MATER JI Chem. Mat. PD JAN-FEB PY 1991 VL 3 IS 1 BP 3 EP 4 DI 10.1021/cm00013a001 PG 2 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA EW486 UT WOS:A1991EW48600002 ER PT J AU FISHMAN, J AF FISHMAN, J TI THE GLOBAL CONSEQUENCES OF INCREASING TROPOSPHERIC OZONE CONCENTRATIONS SO CHEMOSPHERE LA English DT Article ID SURFACE OZONE; CLIMATE AB Recent analyses of long-term records of tropospheric ozone measurements in the Northern Hemisphere suggest that it is increasing at a rate of 1 to 2 percent per year. Because of this, it is argued that the amount of atmospheric warming due to increasing tropospheric ozone is comparable to, or possibly even greater than, the amount of warming due to the increase of carbon dioxide. Unlike all other climatically important trace gases, ozone is toxic, and increases in its concentration will result in serious environmental damage, as well as impairment of human health. RP FISHMAN, J (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401A,HAMPTON,VA 23665, USA. NR 32 TC 31 Z9 42 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PY 1991 VL 22 IS 7 BP 685 EP 695 DI 10.1016/0045-6535(91)90296-P PG 11 WC Environmental Sciences SC Environmental Sciences & Ecology GA FR148 UT WOS:A1991FR14800006 ER PT J AU DRUYAN, LM AF DRUYAN, LM TI THE SENSITIVITY OF SUB-SAHARAN PRECIPITATION TO ATLANTIC SST SO CLIMATIC CHANGE LA English DT Article ID TROPICAL ATLANTIC; SAHEL RAINFALL; TEMPERATURES; ANOMALIES; CLIMATE; AFRICA; MODEL AB The climate model of the Goddard Institute for Space Studies (Hansen et al., 1983) is used to study the sensitivity of sub-Saharan rainfall to Atlantic Ocean SST. Initial changes of SST in the South Atlantic Ocean on March 1st are shown to reduce the June-August sub-Saharan precipitation totals using the model version with an interactive ocean that updates SST. Evidence is offered in support of theories that link Sahel drought with anomalously warm SST in the eastern South Atlantic and the study compares the model's response to spatially coherent SST anomalies with the response to random SST perturbations. The physical processes whereby SST and sea-level pressure synoptics influence the African summer monsoon are discussed in reference to the simulations. Predictibility of Sahel summer rainfall based on spring SST patterns or spring atmospheric circulation patterns is implied by the results. The SST/Sahel drought links are discussed for projections of future climate characteristics. C1 COLUMBIA UNIV,NEW YORK,NY 10027. RP DRUYAN, LM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 21 TC 25 Z9 25 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JAN PY 1991 VL 18 IS 1 BP 17 EP 36 DI 10.1007/BF00142503 PG 20 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA EW091 UT WOS:A1991EW09100003 ER PT J AU BITTKER, DA AF BITTKER, DA TI DETAILED MECHANISM FOR OXIDATION OF BENZENE SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article ID HIGH-TEMPERATURE PYROLYSIS; KINETICS; COMBUSTION; TOLUENE; PHENOL RP BITTKER, DA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 37 TC 64 Z9 65 U1 2 U2 4 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 79 IS 1-3 BP 49 EP 72 DI 10.1080/00102209108951757 PG 24 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA GM557 UT WOS:A1991GM55700003 ER PT J AU DIETRICH, DL CERNANSKY, NP DANIS, AM NAMER, I AF DIETRICH, DL CERNANSKY, NP DANIS, AM NAMER, I TI A PROBABILISTIC MODEL FOR THE IGNITION OF A MONODISPERSE FUEL SPRAY SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Note C1 DREXEL UNIV,DEPT MECH ENGN & MECH,PHILADELPHIA,PA 19104. GE,CINCINNATI,OH 45215. ALFA MANAGEMENT,NEW YORK,NY 10014. RP DIETRICH, DL (reprint author), SVERDRUP TECHNOL INC,NASA,LEWIS RES CTR,MS 500-217,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 11 TC 1 Z9 1 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 79 IS 4-6 BP 325 EP 330 DI 10.1080/00102209108951773 PG 6 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA GR291 UT WOS:A1991GR29100010 ER PT J AU GIVI, P MADNIA, CK STEINBERGER, CJ CARPENTER, MH DRUMMOND, JP AF GIVI, P MADNIA, CK STEINBERGER, CJ CARPENTER, MH DRUMMOND, JP TI EFFECTS OF COMPRESSIBILITY AND HEAT RELEASE IN A HIGH-SPEED REACTING MIXING LAYER SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE SUPERSONIC COMBUSTION; TURBULENT REACTING FLOWS; DIRECT NUMERICAL SIMULATIONS; COMPRESSIBLE SHEAR FLOWS ID NUMERICAL SIMULATIONS; SHEAR-LAYER; TURBULENT; FLOWS C1 NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. RP GIVI, P (reprint author), SUNY BUFFALO,DEPT MECH & AEROSP ENGN,BUFFALO,NY 14260, USA. NR 39 TC 15 Z9 17 U1 0 U2 2 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 78 IS 1-3 BP 33 EP 67 DI 10.1080/00102209108951740 PG 35 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA GB191 UT WOS:A1991GB19100004 ER PT J AU HSIEH, KC SHUEN, JS YANG, V AF HSIEH, KC SHUEN, JS YANG, V TI DROPLET VAPORIZATION IN HIGH-PRESSURE ENVIRONMENTS .1. NEAR CRITICAL CONDITIONS SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article ID COMBUSTION; MIXTURES; LIQUIDS C1 PENN STATE UNIV,DEPT MECH ENGN,UNIVERSITY PK,PA 16802. RP HSIEH, KC (reprint author), NASA,LEWIS RES CTR,SVERDRUP TECHNOL INC,CLEVELAND,OH 44135, USA. NR 40 TC 72 Z9 76 U1 0 U2 3 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 76 IS 1-3 BP 111 EP 132 DI 10.1080/00102209108951705 PG 22 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA FL631 UT WOS:A1991FL63100006 ER PT J AU OLSON, SL AF OLSON, SL TI MECHANISMS OF MICROGRAVITY FLAME SPREAD OVER A THIN SOLID FUEL - OXYGEN AND OPPOSED FLOW EFFECTS SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE MICROGRAVITY; FLAME SPREAD; DIFFUSION FLAME; THERMALLY-THIN SOLID; OPPOSED-FLOW; MECHANISMS RP OLSON, SL (reprint author), NASA,LEWIS RES CTR,MAIL STOP 500-217,CLEVELAND,OH 44135, USA. NR 22 TC 70 Z9 76 U1 0 U2 5 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 76 IS 4-6 BP 233 EP & DI 10.1080/00102209108951711 PG 0 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA FU459 UT WOS:A1991FU45900004 ER PT J AU ROSS, HD SOTOS, RG TIEN, JS AF ROSS, HD SOTOS, RG TIEN, JS TI OBSERVATIONS OF CANDLE FLAMES UNDER VARIOUS ATMOSPHERES IN MICROGRAVITY SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Note C1 CASE WESTERN RESERVE UNIV,DEPT MECH & AEROSP ENGN,CLEVELAND,OH 44106. RP ROSS, HD (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 9 TC 37 Z9 37 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1991 VL 75 IS 1-3 BP 155 EP 160 DI 10.1080/00102209108924084 PG 6 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA FA390 UT WOS:A1991FA39000010 ER PT J AU STABENAU, EK HEMING, TA MITCHELL, JF AF STABENAU, EK HEMING, TA MITCHELL, JF TI RESPIRATORY, ACID-BASE AND IONIC STATUS OF KEMPS RIDLEY SEA-TURTLES (LEPIDOCHELYS-KEMPI) SUBJECTED TO TRAWLING SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-PHYSIOLOGY LA English DT Article ID GAS-EXCHANGE; CARETTA-CARETTA; CHELONIA-MYDAS; GREEN TURTLE; BLOOD; REST AB 1. Kemp's ridley sea turtles were placed in a commercial shrimp trawl equipped with a turtle excluder device (TED), resulting in a burst of apneic swimming and a brief bout of forced submergence (less-than-or-equal-to 7.3 min). 2. Trawl tests induced a significant non-respiratory (metabolic) acidosis; blood pH declined almost 0.4 units and plasma [lactate] increased 6-fold from pre- to post-trawl conditions. 3. Significant changes in blood parameters occurred regardless of the duration of forced submergence (range 2.7-7.3 min), suggesting apneic activity was a significant contributor to the observed acid-base imbalance. C1 NOAA,NATL MARINE FISHERIES SERV,GALVESTON LAB,GALVESTON,TX 77550. NATL MARINE FISHERIES SERV,PASCAGOULA LAB,PASCAGOULA,MS. RP STABENAU, EK (reprint author), UNIV TEXAS,MED BRANCH,PULMONARY RES LABS,GALVESTON,TX 77550, USA. NR 21 TC 31 Z9 32 U1 5 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0300-9629 J9 COMP BIOCHEM PHYS A JI Comp. Biochem. Physiol. A-Physiol. PY 1991 VL 99 IS 1-2 BP 107 EP 111 DI 10.1016/0300-9629(91)90243-6 PG 5 WC Biochemistry & Molecular Biology; Physiology; Zoology SC Biochemistry & Molecular Biology; Physiology; Zoology GA FF833 UT WOS:A1991FF83300020 ER PT J AU POTE, KG ROSS, MD AF POTE, KG ROSS, MD TI EACH OTOCONIA POLYMORPH HAS A PROTEIN UNIQUE TO THAT POLYMORPH SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY LA English DT Article ID SODIUM DODECYL-SULFATE; GEL-ELECTROPHORESIS; ORGANIC MATERIAL; CALCIUM; NITROCELLULOSE; RAT; STATOCONIA; MEMBRANE AB 1. Otoconia, contained within the vestibular portion of the inner ear, are mineralized by one of three polymorphs of calcium carbonate. Each otoconial polymorph contains a unique, major protein. 2. The major protein of calcitic otoconia of members of different vertebrate classes, Amphibia (African clawed frog) and Mammalia (rat), have similar molecular weights. 3. The major protein of calcitic rat otoconia and of vateritic otoconia of the gar may be calcium binding proteins. No protein from the other polymorph, aragonite, appear to have this characteristic. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP POTE, KG (reprint author), UNIV VIRGINIA,DEPT BIOL,GILMER HALL,CHARLOTTESVILLE,VA 22901, USA. NR 28 TC 66 Z9 68 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0305-0491 J9 COMP BIOCHEM PHYS B JI Comp. Biochem. Physiol. B-Biochem. Mol. Biol. PY 1991 VL 98 IS 2-3 BP 287 EP 295 DI 10.1016/0305-0491(91)90181-C PG 9 WC Biochemistry & Molecular Biology; Zoology SC Biochemistry & Molecular Biology; Zoology GA FD216 UT WOS:A1991FD21600017 PM 1873986 ER PT J AU ROTEM, A AF ROTEM, A TI THE FATIGUE BEHAVIOR OF COMPOSITE LAMINATES UNDER VARIOUS MEAN STRESSES SO COMPOSITE STRUCTURES LA English DT Article C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 11 Z9 11 U1 0 U2 0 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. PY 1991 VL 17 IS 2 BP 113 EP 126 DI 10.1016/0263-8223(91)90065-7 PG 14 WC Materials Science, Composites SC Materials Science GA EK325 UT WOS:A1991EK32500002 ER PT J AU SCHWENKE, DW AF SCHWENKE, DW TI COMPACT REPRESENTATION OF VIBRATIONAL WAVE-FUNCTIONS FOR DIATOMIC-MOLECULES SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article AB A new method for determining vibrational wave functions for diatomic molecules is presented. The method is capable of giving very accurate results while at the same time it requires only a small number of parameters to describe the wave functions completely. For example, using a trial function containing only four parameters, it is possible to obtain the ground vibrational energy of H2 to within 0.14 cm-1 of the exact value. In addition, the wave functions satisfy physical boundary conditions as r approaches 0 and infinity. RP SCHWENKE, DW (reprint author), NASA,AMES RES CTR,MS 230-3,MOFFETT FIELD,CA 94035, USA. RI schwenke, david/I-3564-2013 NR 15 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD JAN PY 1991 VL 62 IS 1 BP 1 EP 7 DI 10.1016/0010-4655(91)90115-2 PG 7 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA EZ781 UT WOS:A1991EZ78100001 ER PT J AU OLLENDORF, S NGUYEN, CC AF OLLENDORF, S NGUYEN, CC TI GSFC ROBOTICS RESEARCH FOR SPACE APPLICATIONS SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB The robotics research programs at the Goddard Space Flight Center (GSFC) is structured to increase the scope and efficiency of what man can accomplish in space through the use of robotics. In particular, the main objective is to study the feasibility of assembling and servicing Space Station Freedom and its payloads using a Flight Telerobotic Servicer in teleoperated or autonomous modes. This paper will present in an overview fashion two major robotics research facilities at GSFC, the Development, Integration and Test Facility and the Intelligent Robotics Laboratory. C1 CATHOLIC UNIV AMER,DEPT ELECT ENGN,WASHINGTON,DC 20064. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 18 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 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 121 EP 132 DI 10.1016/0045-7906(91)90029-Y PG 12 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900003 ER PT J AU LEAKE, S AF LEAKE, S TI A CARTESIAN FORCE REFLECTING TELEOPERATION SYSTEM SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB Cartesian force reflecting teleoperation is a relatively new technology; there are no commercially available systems, and only a few laboratory systems. Various methods of mapping master motions to slave motions are presented, taking advantage of the natural structure of teleoperation. The algorithms are implemented in a 386-based Multibus-I system, with all code written in Ada. This system has been used to successfully demonstrate example teleoperation tasks, including peg-in-hole and contour tracing. In addition, a local compliance technique is used, with mixed results. C1 NASA,GODDARD SPACE FLIGHT CTR,ROBOT BRANCH,GREENBELT,MD 20771. NR 5 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 133 EP 146 DI 10.1016/0045-7906(91)90030-4 PG 14 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900004 ER PT J AU NGUYEN, CC ZHOU, ZL MOSIER, GE AF NGUYEN, CC ZHOU, ZL MOSIER, GE TI ANALYSIS AND CONTROL OF A KINEMATICALLY REDUNDANT MANIPULATOR SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB To study space applications of telerobotics, Goddard Space Flight Center (NASA) has recently built a testbed composed mainly of a pair of redundant slave arms having 7 degrees-of-freedom and a master hand controller system. This paper presents the mathematical developments required for the computer simulation study and motion control of the slave arms. First the slave arm forward kinematic transformation is derived using the Denavit-Hartenberg notation and is then reduced to its most simplified form suitable for real-time control applications. The vector cross product method is then applied to obtain the slave arm Jacobian matrix. Using the developed forward kinematic transformation and quaternion representation of the slave arm end-effector orientation, computer simulation is conducted to evaluate the efficiency of the Jacobian in converting joint velocities into Cartesian velocities and to investigate the accuracy of the Jacobian pseudo-inverse for various sampling times. In addition, the equivalence between Cartesian velocities and quaternion is also verified using computer simulation. Finally three control schemes, the joint-space adaptive control scheme, the Cartesian adaptive control scheme and the hybrid position/force control scheme are proposed for controlling the motion of the slave arm end-effector and some preliminary results of the proposed control schemes are presented and discussed. C1 CATHOLIC UNIV AMER,DEPT ELECT ENGN,WASHINGTON,DC 20064. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 21 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 147 EP 161 DI 10.1016/0045-7906(91)90031-T PG 15 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900005 ER PT J AU CAMPBELL, CE AF CAMPBELL, CE TI COLLISION-FREE PATH PLANNING FOR A 3-DEGREE-OF-FREEDOM ROBOT SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB A safe trajectory for a point robot is determined by producing a sequence of edges which are alternately traversed (slides) and then linked by line segment paths (jumps), referred to herein as slide-jump trajectories. A slide-jump trajectory exists if any safe trajectory exists. Hence, if no slide-jump trajectories exist, then there is no solution. An sigma(n2) algorithm (in path safety checks) is developed herein, where n is the number of edges in the environment. Heuristic algorithms are presented which relax the slide-jump trajectory towards a locally optimal, but not necessarily safe, trajectory. The relaxation process constantly maintains the safety of the trajectories as the sum of their path lengths squared is decreased. A 3 degree-of-freedom 3 DOF robot manipulator trajectory is handled through the use of pseudo-obstacles which converts the 3 DOF manipulator problem to a 3 DOF point robot problem. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 14 TC 1 Z9 1 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 163 EP 172 DI 10.1016/0045-7906(91)90032-U PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900006 ER PT J AU VRANISH, JM MCCONNELL, RL MAHALINGAM, S AF VRANISH, JM MCCONNELL, RL MAHALINGAM, S TI CAPACIFLECTOR COLLISION AVOIDANCE SENSORS FOR ROBOTS SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB A state-of-the-art capacitive proximity sensor is being developed by NASA for robot collision-avoidance. The "Capaciflector" (Capacitive Reflector) uses a simple extension of an instrumentation technique for controlling stray capacitance. In this instance a capacitive sensing element, backed by a reflector driven at the same voltage as, and in phase with, the sensor, is used to reflect the field lines away from the grounded robot arm towards the intruding object, thus dramatically increasing range (greater than 12 in. with the reflector/one without) and sensitivity. The stand-off distance of this system from the grounded robot arm is essentially zero. In this paper the present status of sensor development is described to include the basic workings of the sensor charges and fields, the electronic circuitry and mathematical modeling. Test results are given. C1 CARNEGIE MELLON UNIV,DEPT MECH ENGN,PITTSBURGH,PA 15213. NASA,GODDARD SPACE FLIGHT CTR,ROBOT BRANCH,GREENBELT,MD 20771. W VIRGINIA UNIV,DEPT ELECT & COMP ENGN,MORGANTOWN,WV 26506. NR 7 TC 4 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 173 EP 179 DI 10.1016/0045-7906(91)90033-V PG 7 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900007 ER PT J AU LERNER, BT MORELLI, MV AF LERNER, BT MORELLI, MV TI EXTENSIONS OF ALGEBRAIC IMAGE OPERATORS - AN APPROACH TO MODEL-BASED VISION SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR ID HOUGH TRANSFORM; PROCESSOR AB We extend our previous research on a highly structured and compact algebraic representation of grey-level images which can be viewed as fuzzy sets. Addition and multiplication are defined for the set of all grey-level images, which can then be described as polynomials of two variables. Utilizing this new algebraic structure, we have devised an innovative, efficient edge detection scheme. An accurate method for deriving gradient component information from this edge detector is presented. A continuous single-pixel-wide edge as well as inherently parallel global operations are some of the advantages that this edge detector possesses over classical convolution-type edge detectors. Based upon this new edge detection system we have developed a robust method for linear feature extraction by combining the techniques of a Hough transform and a line follower. The major advantage of this feature extractor is its general, object-independent nature. Target attributes, such as line segment lengths, intersections, angles of intersection and endpoints are derived by the feature extraction algorithm and employed during model matching. The algebraic operators are global operations which are easily reconfigured to operate on any size or shape region. This provides a natural platform from which to pursue dynamic scene analysis. We discuss a method for optimizing the linear feature extractor for a general-purpose processor which capitalizes on the spatially reconfigurable nature of the edge detector/gradient component operator. C1 TEXAS TECH UNIV,DEPT ELECT ENGN,OPT SYST LAB,LUBBOCK,TX 79409. USN ACAD,ANNAPOLIS,MD 21402. NASA,GODDARD SPACE FLIGHT CTR,ROBOT LAB,GREENBELT,MD 20771. NR 11 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 181 EP 190 DI 10.1016/0045-7906(91)90034-W PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900008 ER PT J AU NGUYEN, CC ANTRAZI, SC ZHOU, ZL CAMPBELL, CE AF NGUYEN, CC ANTRAZI, SC ZHOU, ZL CAMPBELL, CE TI ANALYSIS AND IMPLEMENTATION OF A 6-DOF STEWART PLATFORM-BASED ROBOTIC WRIST SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article; Proceedings Paper CT 3RD BIANNUAL INTERNATIONAL SYMP ON ROBOTS AND MANUFACTURING ( ISRAM ) CY JUL 18-20, 1990 CL BURNABY, CANADA SP NASA, GODDARD SPACE FLIGHT CTR AB In this paper, we present the kinematic analysis and implementation of a 6 DOF robotic wrist which is mounted to a general open-kinematic chain manipulator to serve as a testbed for studying precision robotic assembly in space. The wrist design is based on the Stewart-Platform mechanism and consists mainly of two platforms and six linear actuators driven by d.c. motors. Position feedback is achieved by linear displacement transducers mounted along the actuators and force feedback is obtained by a 6 DOF force sensor mounted between the gripper and the payload platform. The robot wrist inverse kinematics which computes the required actuator lengths corresponding to Cartesian variables has a closed-form solution. The forward kinematics is solved iteratively using the Newton-Raphson method which simultaneously provides a modified Jacobian matrix which relates length velocities to Cartesian translational velocities and time rates of change of roll-pitch-yaw angles. Results of computer simulation conducted to evaluate the efficiency of the forward kinematics and modified Jacobian matrix are presented and discussed. C1 CATHOLIC UNIV AMER,DEPT ELECT ENGN,ROBOT & CONTROL LAB,WASHINGTON,DC 20064. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 21 TC 4 Z9 9 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP 191 EP 203 DI 10.1016/0045-7906(91)90035-X PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900009 ER PT J AU NGUYEN, CC OLLENDORF, S AF NGUYEN, CC OLLENDORF, S TI ROBOTICS RESEARCH AT THE NASA GODDARD-SPACE-FLIGHT-CENTER SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Editorial Material C1 CATHOLIC UNIV AMER,DEPT ELECT ENGN,WASHINGTON,DC 20064. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PY 1991 VL 17 IS 3 BP R7 EP R8 DI 10.1016/0045-7906(91)90028-X PG 2 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA GP939 UT WOS:A1991GP93900002 ER PT J AU DEISSLER, RG AF DEISSLER, RG TI NUMERICAL-SOLUTION FOR THE VELOCITY-DERIVATIVE SKEWNESS OF A LOW REYNOLDS-NUMBER TURBULENT-LIKE DECAYING NAVIER-STOKES FLOW SO COMPUTERS & FLUIDS LA English DT Note AB The variation of the velocity-derivative skewness of a Navier-Stokes flow as Re --> 0 is calculated numerically. The value of the skewness, which has been somewhat controversial, is shown to become small at low Re, in agreement with intuitive arguments that nonlinear terms should be negligible. RP DEISSLER, RG (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PY 1991 VL 20 IS 1 BP 89 EP 91 DI 10.1016/0045-7930(91)90029-H PG 3 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA GC835 UT WOS:A1991GC83500007 ER PT J AU VATSA, VN AF VATSA, VN TI VISCOUS-FLOW SOLUTIONS FOR SLENDER BODIES OF REVOLUTION AT INCIDENCE SO COMPUTERS & FLUIDS LA English DT Article AB Flow over slender prolate spheroids at incidence is examined. The incidence angle is chosen high enough to cause streamwise separation of the flow in addition to crossflow separation generally observed at lower incidence angles. The free-stream Mach number for the cases investigated here is subsonic, thus precluding the use of parabolized procedures. Laminar, transitional and turbulent flow cases are investigated. RP VATSA, VN (reprint author), NASA,LANGLEY RES CTR,MS 128,HAMPTON,VA 23665, USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PY 1991 VL 20 IS 3 BP 313 EP 320 DI 10.1016/0045-7930(91)90047-L PG 8 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA GJ426 UT WOS:A1991GJ42600010 ER PT J AU WORNOM, SF AF WORNOM, SF TI APPLICATION OF 2-POINT IMPLICIT CENTRAL-DIFFERENCE METHODS TO HYPERBOLIC SYSTEMS SO COMPUTERS & FLUIDS LA English DT Article ID EULER EQUATIONS; STEADY-STATE; SCHEMES AB This paper presents a general solution algorithm for the set of difference equations that arise. when two-point central differences are used to approximate the flux difference terms in systems of hyperbolic differential equations. The general algorithm eliminates the weak points associated with the non-standard algorithm reported by Wornom and Hafez [AIAA Jl 24(2), 215 (1986)]. The disadvantages of their algorithm relate to its implementation. It consists of separate algorithms for subsonic, supersonic, sonic and shock cells, applied individually, which presents a major bookkeeping problem when multiple sonic and shock cells are present. The general algorithm eliminates this problem and introduces an improved shock treatment which produces shocks with at most one interior shock point. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 12 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PY 1991 VL 20 IS 3 BP 321 EP 331 DI 10.1016/0045-7930(91)90048-M PG 11 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA GJ426 UT WOS:A1991GJ42600011 ER PT J AU KAVSAOGLU, MS KAYNAK, U VANDALSEM, WR AF KAVSAOGLU, MS KAYNAK, U VANDALSEM, WR TI 3-DIMENSIONAL APPLICATION OF THE JOHNSON-KING TURBULENCE MODEL FOR A BOUNDARY-LAYER DIRECT METHOD SO COMPUTERS & FLUIDS LA English DT Article AB The Johnson-King turbulence model [1; AIAA Paper 84-0175 (1984)] as extended to three-dimensional flows was evaluated using a finite-difference boundary-layer direct method. Calculations were compared against the experimental data of the well-known van den Berg-Elsenaar [2; Report NLR-TR-72092U (1972)] incompressible flow over an infinite swept-wing, as well as with some other boundary-layer methods. The Johnson-King turbulence model, which includes the non-equilibrium effects in a developing turbulent boundary layer, was found to significantly improve the predictive quality of a direct boundary-layer method. The improvement was especially visible in the computations with increased three-dimensionality of the mean flow, larger integral parameters and decreasing eddy-viscosity and shear-stress magnitudes in the streamwise direction; all in better agreement with the experiment than simple mixing-length-based methods. C1 TUSAS AEROSP IND, KAVAKHDERE 06690, TURKEY. NASA, AMES RES CTR, ACF BRANCH, MOFFETT FIELD, CA 94035 USA. RP KAVSAOGLU, MS (reprint author), MIDDLE E TECH UNIV, DEPT AERONAUT ENGN, ANKARA 06531, TURKEY. NR 23 TC 0 Z9 0 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 EI 1879-0747 J9 COMPUT FLUIDS JI Comput. Fluids PY 1991 VL 19 IS 3-4 BP 363 EP 376 DI 10.1016/0045-7930(91)90061-L PG 14 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA FY061 UT WOS:A1991FY06100010 ER PT J AU SCROGGS, JS AF SCROGGS, JS TI AN ITERATIVE METHOD FOR SYSTEMS OF NONLINEAR HYPERBOLIC-EQUATIONS SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article AB An iterative algorithm for the efficient solution of systems of nonlinear hyperbolic equations is presented. Parallelism is evident at several levels. In the formation of the iteration, the equations are decoupled, thereby providing large grain parallelism. Parallelism may also be exploited within the solves for each equation. Convergence of the iteration is established via a bounding function argument. Experimental results in two-dimensions are presented. RP SCROGGS, JS (reprint author), NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665, USA. NR 9 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 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PY 1991 VL 21 IS 5 BP 137 EP 144 DI 10.1016/0898-1221(91)90223-Q PG 8 WC Computer Science, Interdisciplinary Applications; Mathematics, Applied SC Computer Science; Mathematics GA EY298 UT WOS:A1991EY29800013 ER PT J AU HAJELA, P BERKE, L AF HAJELA, P BERKE, L TI NEUROBIOLOGICAL COMPUTATIONAL MODELS IN STRUCTURAL-ANALYSIS AND DESIGN SO COMPUTERS & STRUCTURES LA English DT Article AB This paper examines the role of neural computing strategies in structural analysis and design. A principal focus of the work resides in the use of neural networks to represent the force-displacement relationship in static structural analysis. Such models provide computationally efficient capabilities for reanalysis, and appear to be well suited for application in numerical optimum design. The paper presents an overview of the neural computing approach, with special emphasis on supervised learning techniques adopted in the present work. Special features of such learning strategies which have a direct bearing on numerical accuracy and efficiency, are examined in the context of representative structural optimization problems. C1 NASA,LEWIS RES CTR,DIV STRUCT,CLEVELAND,OH 44135. RP HAJELA, P (reprint author), RENSSELAER POLYTECH INST,TROY,NY 12181, USA. NR 11 TC 82 Z9 85 U1 2 U2 2 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. PY 1991 VL 41 IS 4 BP 657 EP 667 DI 10.1016/0045-7949(91)90178-O PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA GQ748 UT WOS:A1991GQ74800011 ER PT J AU BAKHLE, MA MAHAJAN, AJ KEITH, TG STEFKO, GL AF BAKHLE, MA MAHAJAN, AJ KEITH, TG STEFKO, GL TI CASCADE FLUTTER ANALYSIS WITH TRANSIENT-RESPONSE AERODYNAMICS SO COMPUTERS & STRUCTURES LA English DT Article ID FLOWS; COMPUTATION AB Two methods for calculating linear frequency domain unsteady aerodynamic coefficients from a time-marching full-potential cascade solver are developed and verified. In the first method, the influence coefficient method, solutions to elemental problems are superposed to obtain the solutions for a cascade in which all blades are vibrating with a constant interblade phase angle. The elemental problem consists of a single blade in the cascade oscillating while the other blades remain stationary. In the second method, the pulse response method, the response to the transient motion of a blade is used to calculate influence coefficients. This is done by calculating the Fourier transforms of the blade motion and the response. Both methods are validated by comparison with the harmonic oscillation method, in which all the airfoils are oscillated, and are found to give accurate results. The aerodynamic coefficients obtained from these methods are used for frequency domain flutter calculations involving a typical section blade structural model. Flutter calculations are performed for two examples over a range of subsonic Mach numbers using both flat plates and actual airfoils. C1 NASA,LEWIS RES CTR,STRUCT DYNAM BRANCH,CLEVELAND,OH 44135. RP BAKHLE, MA (reprint author), UNIV TOLEDO,DEPT MECH ENGN,TOLEDO,OH 43606, USA. NR 25 TC 8 Z9 9 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. PY 1991 VL 41 IS 5 BP 1073 EP 1085 DI 10.1016/0045-7949(91)90302-3 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA GT924 UT WOS:A1991GT92400023 ER PT J AU TROWBRIDGE, DA GRADY, JE AIELLO, RA AF TROWBRIDGE, DA GRADY, JE AIELLO, RA TI LOW VELOCITY IMPACT ANALYSIS WITH NASTRAN SO COMPUTERS & STRUCTURES LA English DT Article ID PLATES AB A nonlinear elastic force-displacement relationship is used to calculate the transient impact force and local deformation at the point of contact between impactor and target. The nonlinear analysis and transfer function capabilities of NASTRAN are used to define a finite element model that behaves globally linearly elastic, and locally nonlinear elastic to model the local contact behavior. Results are presented for two different structures: a uniform cylindrical rod impacted longitudinally; and an orthotropic plate impacted transversely. Calculated impact force and transient structural response of the targets are shown to compare well with result measured in experimental tests. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP TROWBRIDGE, DA (reprint author), ANALEX CORP,FAIRVIEW PK,OH 44126, USA. NR 20 TC 5 Z9 6 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. PY 1991 VL 40 IS 4 BP 977 EP 984 DI 10.1016/0045-7949(91)90328-J PG 8 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA GB193 UT WOS:A1991GB19300020 ER PT J AU NOOR, AK BURTON, WS AF NOOR, AK BURTON, WS TI PREDICTOR-CORRECTOR PROCEDURES FOR THERMAL BUCKLING ANALYSIS OF MULTILAYERED COMPOSITE PLATES SO COMPUTERS & STRUCTURES LA English DT Article AB A study is made of two predictor-corrector procedures for the accurate determination of global, as well as detailed, thermal buckling response characteristics of composite plates. Both procedures use first-order shear deformation theory in the predictor phase, but differ in the elements of the computational model being adjusted in the corrector phase. The first procedure calculates a posteriori estimates of the composite correction factors and uses them to adjust the transverse shear stiffnesses of the plate. The second procedure calculates a posteriori the functional dependence of the displacement components on the thickness coordinate. The corrected quantities are then used in conjunction with three-dimensional equations to obtain better estimates for the different response quantities. Extensive numerical results are presented, showing the effects of variation in the geometric and lamination parameters for antisymmetrically laminated composite plates subjected to uniform temperature rise, on the accuracy of the thermal buckling response obtained by predictor-corrector procedures. Comparison is also made with solutions obtained by other computational models based on two-dimensional shear deformation theories. For each problem, the standard of comparison is taken to be the analytic three-dimensional thermoelasticity solution, with prebuckling deformations accounted for. The numerical examples clearly demonstrate the accuracy and effectiveness of the predictor-corrector procedures. RP UNIV VIRGINIA, NASA, LANGLEY RES CTR, CTR COMPUTAT STRUCT TECHNOL, HAMPTON, VA 23665 USA. NR 23 TC 19 Z9 19 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7949 EI 1879-2243 J9 COMPUT STRUCT JI Comput. Struct. PY 1991 VL 40 IS 5 BP 1071 EP 1084 DI 10.1016/0045-7949(91)90380-5 PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA GC886 UT WOS:A1991GC88600002 ER PT J AU NOOR, AK BURTON, WS AF NOOR, AK BURTON, WS TI STEADY-STATE HEAT-CONDUCTION IN MULTILAYERED COMPOSITE PLATES AND SHELLS SO COMPUTERS & STRUCTURES LA English DT Article AB A study is made of a predictor-corrector procedure for the accurate determination of the temperature and heat flux distributions in thick multilayered composite plates and shells. A linear through-the-thickness temperature distribution is used in the predictor phase. The functional dependence of temperature on the thickness coordinate is then calculated a posteriori and used in the corrector phase. Extensive numerical results are presented for linear steady-state heat conduction problems, showing the effects of variation in the geometric and lamination parameters on the accuracy of the thermal response predictions of the predictor-corrector approach. Both antisymmetrically laminated anisotropic plates and multilayered orthotropic cylinders are considered. The solutions are assumed to be periodic in the surface coordinates. For each problem the standard of comparison is taken to be the analytic three-dimensional solution based on treating each layer as a homogeneous anisotropic medium. The potential of the predictor-corrector approach for predicting the thermal response of multilayered plates and shells with complicated geometry is discussed. RP NOOR, AK (reprint author), UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT,HAMPTON,VA 23665, USA. NR 22 TC 12 Z9 12 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. PY 1991 VL 39 IS 1-2 BP 185 EP 193 DI 10.1016/0045-7949(91)90086-2 PG 9 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA FF518 UT WOS:A1991FF51800019 ER PT J AU PATNAIK, SN BERKE, L GALLAGHER, RH AF PATNAIK, SN BERKE, L GALLAGHER, RH TI INTEGRATED FORCE METHOD VERSUS DISPLACEMENT METHOD FOR FINITE-ELEMENT ANALYSIS SO COMPUTERS & STRUCTURES LA English DT Article AB A novel formulation termed the 'integrated force method' (IFM) has been developed in recent years for analyzing structures. In this method all the internal forces are taken as independent variables, and the system equilibrium equations (EEs) are integrated with the global compatability conditions (CCs) to form the governing set of equations. In IFM the CCs are obtained from the strain formulation of St. Venant, and no choices of redundant load systems have to be made, in contrast to the standard force method (SFM). This property of IFM allows the generation of the governing equation to be automated straightforwardly, as it is in the popular stiffness method (SM). In this paper IFM and SM are compared relative to the structure of their respective equations, their conditioning, required solution methods, overall computational requirements, and convergence properties as these factors influence the accuracy of the results. Overall, this new version of the force method produces more accurate results than the stiffness method for comparable computational cost. C1 CLARKSON UNIV,POTSDAM,NY 13676. RP PATNAIK, SN (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 33 TC 33 Z9 33 U1 1 U2 3 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. PY 1991 VL 38 IS 4 BP 377 EP 407 DI 10.1016/0045-7949(91)90037-M PG 31 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA FA964 UT WOS:A1991FA96400001 ER PT J AU HUCK, FO ALTERGARTENBERG, R RAHMAN, ZU AF HUCK, FO ALTERGARTENBERG, R RAHMAN, ZU TI IMAGE GATHERING AND DIGITAL RESTORATION FOR FIDELITY AND VISUAL QUALITY SO CVGIP-GRAPHICAL MODELS AND IMAGE PROCESSING LA English DT Article ID INFORMATION C1 OLD DOMINION UNIV,NORFOLK,VA 23529. SCI & TECHNOL CORP,HAMPTON,VA 23666. RP HUCK, FO (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 28 TC 9 Z9 9 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 1049-9652 J9 CVGIP-GRAPH MODEL IM PD JAN PY 1991 VL 53 IS 1 BP 71 EP 84 DI 10.1016/1049-9652(91)90021-B PG 14 WC Computer Science, Software Engineering SC Computer Science GA FA498 UT WOS:A1991FA49800009 ER PT J AU LUNDY, GM MILLER, RE AF LUNDY, GM MILLER, RE TI SPECIFICATION AND ANALYSIS OF A DATA TRANSFER PROTOCOL USING SYSTEMS OF COMMUNICATING MACHINES SO DISTRIBUTED COMPUTING LA English DT Article DE COMMUNICATION PROTOCOL; FORMAL MODEL; SPECIFICATION; ANALYSIS; FORMAL DESCRIPTION TECHNIQUE AB A model for communication protocols called systems of communicating machines is used to specify a data transfer protocol with variable window size (e.g., HDLC), which is an arbitrary nonnegative integer, and to analyze it for freedom from deadlocks. The model uses a combination of finite state machines and variables. This allows the size of the specification (i.e., number of states and variables) to be linear in the window size, a considerable reduction from the pure finite state machine model. A new type of analysis is demonstrated which we call system state analysis. This is similar to the reachability analysis used in the pure finite state model, but it provides substantial simplication by reducing the number of states generated. For example, with the protocol in this paper, if w is the window size, then the global analysis produces O(w5) states, while the system state analysis produces O(w3) states. The system state analysis is then combined with an inductive proof, extending the analysis to all nonnegative integers w. C1 UNIV MARYLAND,DEPT COMP SCI,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,CTR EXCELLENCE SPACE DATA & INFORMAT SCI,GREENBELT,MD 20771. RP LUNDY, GM (reprint author), USN,POSTGRAD SCH,DEPT COMP SCI,MONTEREY,CA 93943, USA. NR 42 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0178-2770 J9 DISTRIB COMPUT JI Distrib. Comput. PY 1991 VL 5 IS 3 BP 145 EP 157 DI 10.1007/BF02252957 PG 13 WC Computer Science, Theory & Methods SC Computer Science GA GV414 UT WOS:A1991GV41400004 ER PT B AU VERTER, F AF VERTER, F BE COMBES, F CASOLI, F TI IN SEARCH OF A GALAXY SAMPLE TO STUDY THE SYSTEMATIC PROPERTIES OF CO EMISSION FROM GALAXIES SO DYNAMICS OF GALAXIES AND THEIR MOLECULAR CLOUD DISTRIBUTIONS SE IAU SYMPOSIA LA English DT Proceedings Paper CT 146TH SYMP OF THE INTERNATIONAL ASTRONOMICAL UNION ON DYNAMICS OF GALAXIES AND THEIR MOLECULAR CLOUD DISTRIBUTIONS CY JUN 04-09, 1990 CL PARIS, FRANCE SP INT ASTRON UNION, CNRS, OBSERV PARIS, INST RECH & APPL METHODS DEV, CTR NATL ETUDES SPATIALES ID SPIRAL GALAXIES; STAR FORMATION; LUMINOSITY FUNCTION; IRREGULAR GALAXIES; NEUTRAL HYDROGEN; VIRGO CLUSTER; ATOMIC GAS; RATIO RP VERTER, F (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 685,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA DORDRECHT BN 0-7923-1096-9 J9 IAU SYMP PY 1991 VL 146 BP 137 EP 145 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BV33Q UT WOS:A1991BV33Q00041 ER PT B AU TELESCO, CM CAMPINS, H JOY, M DIETZ, K DECHER, R AF TELESCO, CM CAMPINS, H JOY, M DIETZ, K DECHER, R BE COMBES, F CASOLI, F TI INFRARED IMAGING OF M82 - A STARBURST IN AN EDGE-ON BARRED GALAXY SO DYNAMICS OF GALAXIES AND THEIR MOLECULAR CLOUD DISTRIBUTIONS SE IAU SYMPOSIA LA English DT Proceedings Paper CT 146TH SYMP OF THE INTERNATIONAL ASTRONOMICAL UNION ON DYNAMICS OF GALAXIES AND THEIR MOLECULAR CLOUD DISTRIBUTIONS CY JUN 04-09, 1990 CL PARIS, FRANCE SP INT ASTRON UNION, CNRS, OBSERV PARIS, INST RECH & APPL METHODS DEV, CTR NATL ETUDES SPATIALES RP TELESCO, CM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,MAIL CODE ES-63,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA DORDRECHT BN 0-7923-1096-9 J9 IAU SYMP PY 1991 VL 146 BP 284 EP 284 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BV33Q UT WOS:A1991BV33Q00087 ER PT J AU ROTH, LE AF ROTH, LE TI SCHROETER RATIOS FOR MARTIAN CRATERS - RADAR RESULTS SO EARTH MOON AND PLANETS LA English DT Article ID OBLITERATION HISTORY; SURFACE PROPERTIES; MARS; TOPOGRAPHY; ALTIMETRY; OPPOSITION AB Schroeter's ratios (ratios of the rim volume to the apparent volume) are determined for a sample of 29 large, degraded Martian craters selected from the Goldstone Mars radar altimetry data. On the average, the values of the calculated Schroeter's ratios are about two orders of magnitude smaller than the same ratios for fresh lunar craters. This indicates a severe rim volume deficit in degraded Martian craters and it provides an additional support to the notion of a widespread resurfacing of intercrater plains on Mars. Schroeter's ratios for degraded craters could provide a semi-quantitative measure of the effects of the modification processes that had been active on Mars and on the other planetary bodies. RP ROTH, LE (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 45 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 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PD JAN PY 1991 VL 52 IS 1 BP 27 EP 49 DI 10.1007/BF00113829 PG 23 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA FC181 UT WOS:A1991FC18100003 ER PT B AU BERATAN, DN ONUCHIC, JN AF BERATAN, DN ONUCHIC, JN BE BOLTON, JR MATAGA, N MCLENDON, G TI ELECTRON-TRANSFER - FROM MODEL COMPOUNDS TO PROTEINS SO ELECTRON TRANSFER IN INORGANIC, ORGANIC, AND BIOLOGICAL SYSTEMS SE ADVANCES IN CHEMISTRY SERIES LA English DT Proceedings Paper CT SYMP ON ELECTRON TRANSFER IN INORGANIC, ORGANIC, AND BIOLOGICAL SYSTEMS CY DEC 17-22, 1989 CL HONOLULU, HI SP INT CHEM CONGRESS PACIFIC BASIN SOC RP BERATAN, DN (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Beratan, David/C-5098-2011 NR 0 TC 19 Z9 19 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA WASHINGTON BN 0-8412-1846-3 J9 ADV CHEM SER PY 1991 VL 228 BP 71 EP 90 PG 20 WC Biochemistry & Molecular Biology; Chemistry, Inorganic & Nuclear; Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Biochemistry & Molecular Biology; Chemistry; Physics GA BT96G UT WOS:A1991BT96G00005 ER PT J AU HOSSNER, LR MING, DW HENNINGER, DL ALLEN, ER AF HOSSNER, LR MING, DW HENNINGER, DL ALLEN, ER TI LUNAR OUTPOST AGRICULTURE SO ENDEAVOUR LA English DT Article AB America's long-term commitment to a new Space Exploration Initiative has focused attention on the basic requirements for establishing a permanently manned lunar outpost and, ultimately, a martian one. High among these is the development of Regenerative Life Support Systems - with lunar agriculture an essential component - to provide a high level of self-sufficiency. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV CREW & THERMAL SYST,HOUSTON,TX 77058. OKLAHOMA STATE UNIV,SOIL CHEM,STILLWATER,OK 74078. RP HOSSNER, LR (reprint author), TEXAS A&M UNIV SYST,SOIL CHEM,COLLEGE STN,TX 77843, USA. NR 25 TC 6 Z9 6 U1 4 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0160-9327 J9 ENDEAVOUR JI Endeavour PY 1991 VL 15 IS 2 BP 79 EP 85 DI 10.1016/S0160-9327(05)80009-2 PG 7 WC History & Philosophy Of Science; Multidisciplinary Sciences SC History & Philosophy of Science; Science & Technology - Other Topics GA FY797 UT WOS:A1991FY79700007 PM 11537088 ER PT J AU MATSUKAWA, S KEIL, LC REID, IA AF MATSUKAWA, S KEIL, LC REID, IA TI ROLE OF ENDOGENOUS ANGIOTENSIN-II IN THE CONTROL OF VASOPRESSIN SECRETION DURING HYPOVOLEMIA AND HYPOTENSION IN CONSCIOUS RABBITS SO ENDOCRINOLOGY LA English DT Article ID CONVERTING-ENZYME-INHIBITION; SODIUM-NITROPRUSSIDE; PLASMA; CAPTOPRIL; RENIN; HEMORRHAGE; SYSTEM; DOGS; RESPONSES; RELEASE AB In order to investigate the physiological role of angiotensin II (ANG II) in the control of vasopressin (VP) secretion, the VP responses to hypotension induced by hemorrhage (20 ml/kg, n = 10) or nitroprusside infusion (1-10-mu-g/kg. min, n = 9) were studied with or without blockade of ANG II formation by the converting enzyme inhibitor captopril in conscious rabbits. Administration of captopril (5 mg/kg, iv) caused a small decrease in mean arterial pressure but did not enhance the hypotensive response to subsequent hemorrhage or nitroprusside infusion. The renin response to both stimuli was enhanced by captopril, whereas the increase in plasma ANG II concentration was attenuated. Plasma VP (PAVP) concentration increased during hemorrhage (2.0 +/- 0.2-113.6 +/- 47.7 pg/ml, P < 0.01) and nitroprusside infusion (2.1 +/- 0.3-5.1 +/- 1.0 pg/ ml, P < 0.01). Captopril did not change basal plasma PAVP, nor did it attenuate the VP responses to hemorrhage or nitroprusside. Indeed, captopril tended to enhance the VP responses to hemorrhage (2.3 +/- 0.3-147.1 +/- 65.9 pg/ml) and nitroprusside infusion (1.9 +/- 0.2-15.4 +/- 6.0 pg/ml). The relationship between log PAVP and mean arterial pressure during hemorrhage and nitroprusside infusion in the presence of captopril was not different than in the absence of captopril. These results indicate that in conscious rabbits, the renin-angiotensin system does not contribute to the increase in VP secretion during hypotension induced by hemorrhage or nitroprusside infusion. C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,BOX 0444,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. FU NHLBI NIH HHS [HL-29714] NR 37 TC 20 Z9 20 U1 0 U2 0 PU ENDOCRINE SOC PI BETHESDA PA 4350 EAST WEST HIGHWAY SUITE 500, BETHESDA, MD 20814-4110 SN 0013-7227 J9 ENDOCRINOLOGY JI Endocrinology PD JAN PY 1991 VL 128 IS 1 BP 204 EP 210 PG 7 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA EQ492 UT WOS:A1991EQ49200027 PM 1986918 ER PT J AU LIEBOWITZ, H NOOR, AK MOYER, TE AF LIEBOWITZ, H NOOR, AK MOYER, TE TI NEW COMPUTING SYSTEMS AND THEIR IMPACT ON STRUCTURAL AND FRACTURE-MECHANICS CALCULATIONS SO ENGINEERING FRACTURE MECHANICS LA English DT Article AB Needless to say, advances in computer technology have had a profound effect on structure technology, as well as on various engineering and applied science disciplines. The advances forcasted for the next decade will prove to have an even greater impact on the technology. This talk will highlight some of the advances made in computer technology and their impact on structure technology. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,MAIL STOP 210,HAMPTON,VA 23665. RP LIEBOWITZ, H (reprint author), GEORGE WASHINGTON UNIV,SCH ENGN & APPL SCI,WASHINGTON,DC 20052, USA. NR 0 TC 2 Z9 2 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PY 1991 VL 40 IS 4-5 BP 687 EP 704 DI 10.1016/0013-7944(91)90229-T PG 18 WC Mechanics SC Mechanics GA GU706 UT WOS:A1991GU70600002 ER PT J AU SHIVAKUMAR, KN NEWMAN, JC AF SHIVAKUMAR, KN NEWMAN, JC TI STRESS INTENSITY FACTORS FOR LARGE ASPECT RATIO SURFACE AND CORNER CRACKS AT A SEMICIRCULAR NOTCH IN A TENSION SPECIMEN SO ENGINEERING FRACTURE MECHANICS LA English DT Article ID ALTERNATING METHOD; LOADINGS AB Stress intensity factor solutions for semi-elliptic surface and quarter-elliptic corner cracks emanating from a semi-circular notch in a tension specimen are presented. A three-dimensional finite-element analysis in conjunction with the equivalent domain integral was used to calculate stress intensity factors (SIF). SIF solutions for surface or corner crack (crack length to depth ratio of 2) at a notch are presented for a wide range of crack sizes and notch radii. Results showed that the SIF are larger for larger crack lengths and for larger notch radii. The SIF are nearly constant all along the crack front for deep surface cracks and for all corner cracks analysed. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 19 TC 22 Z9 23 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0013-7944 J9 ENG FRACT MECH JI Eng. Fract. Mech. PY 1991 VL 38 IS 6 BP 467 EP 473 DI 10.1016/0013-7944(91)90096-J PG 7 WC Mechanics SC Mechanics GA FF840 UT WOS:A1991FF84000010 ER PT J AU BOEHLERT, GW YAMADA, J AF BOEHLERT, GW YAMADA, J TI INTRODUCTION TO THE SYMPOSIUM ON ROCKFISHES SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Editorial Material ID SEBASTES-SCHLEGELI; GENUS SEBASTES; SCORPAENIDAE; ENERGETICS; LARVAE C1 UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. HOKKAIDO UNIV,FAC FISHERIES,PHYSIOL & ECOL LAB,HAKODATE,HOKKAIDO 041,JAPAN. RP BOEHLERT, GW (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 49 TC 13 Z9 16 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 9 EP 13 DI 10.1007/BF02296871 PG 5 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500002 ER PT J AU BOEHLERT, GW KUSAKARI, M YAMADA, J AF BOEHLERT, GW KUSAKARI, M YAMADA, J TI OXYGEN-CONSUMPTION OF GESTATING FEMALE SEBASTES-SCHLEGELI - ESTIMATING THE REPRODUCTIVE COSTS OF LIVEBEARING SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR DE VIVIPARITY; EMBRYOS; TELEOST; RESPIRATION ID GENUS SEBASTES; DYNAMIC ACTION; ROCKFISH; FISH; ENERGETICS; GROWTH; FOOD; SCORPAENIDAE; DIPLOPROA; FECUNDITY AB During gestation, live-bearing fishes incur physiological energy costs, including provision of energy and respiratory gases to the developing embryos and removal of waste products. Fecundity in the genus Sebastes is high, and the ovaries represent a significant portion of the weight of gestating females. In this study, we compare oxygen consumption of gestating females with non-gestating females and males of kurosoi, Sebastes schlegeli, to estimate these costs. Oxygen consumption by pregnant females is significantly higher than that of males and immature females at similar sizes and weights. We estimate that a 1.5 kg gestating female consumes 68% more oxygen than a non-gestating fish during the 51.5-day period of gestation. Such an increase in oxygen consumption rates may have important implications to the metabolic scope of gestating females. The additional oxygen consumed by gestating females is greater than that predicted for the embryos alone, suggesting that costs of increased gill ventilation, ionic and osmotic regulation and cardiac output are relatively high. Such energetic costs represent a quantifiable expense of the viviparous mode of reproduction in Sebastes as compared with oviparous species. C1 UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. HOKKAIDO INST MARICULTURE,SHIKABE,HOKKAIDO,JAPAN. HOKKAIDO UNIV,FAC MINERAL CHEM,PHYSIOL & ECOL LAB,HAKODATE,HOKKAIDO 041,JAPAN. RP BOEHLERT, GW (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 41 TC 20 Z9 21 U1 0 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 81 EP 89 DI 10.1007/BF02296879 PG 9 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500010 ER PT J AU CONTE, FP TAKANO, K TAKEMURA, A BOEHLERT, GW AF CONTE, FP TAKANO, K TAKEMURA, A BOEHLERT, GW TI ONTOGENY OF THE SODIUM-PUMP IN EMBRYOS OF ROCKFISH OF THE GENUS SEBASTES SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR DE NA; K-ATPASE; TRANSPORTING ATPASE; FISH LARVAE; DEVELOPMENT ID TELEOST CLINUS-SUPERCILIOSUS; FUNDULUS-HETEROCLITUS; ENERGETICS; BERMUDAE; SEAWATER; SALINITY; BALANCE; LARVAE; FLUID; EGGS AB The purpose of the present investigation was to determine at what stages of embryonic development the sodium pump (Na +, K + -activated ATP phosphohydrolase, EC 3.6.1.3) appears and whether the ontogeny of the sodium pump plays a role in the matrotrophic viviparity of Sebastes. Early larval stages (stages 1-14) had embryonic tissues nearly devoid of Na, K-ATPase activity. After epiboly, tissues from embryos taken from both species, S. schlegeli and S. taczanowskii, had significant levels of enzymatic activity coincident with the appearance of neuronal tissue in the head fold (stages 15-20). Maximal levels of specific activities of the enzyme were reached with the onset of the vascular circulation and the opening of the buccal cavity together with maturation of the midgut and hindgut regions of the intestinal tract (stages 26 and 28). Ouabain, a specific inhibitor of Na, K-ATPase, was used to measure survival of embryos placed in different seawater concentrations under in vitro conditions. The most sensitive stages to external ouabain were 26-30. These findings support the hypothesis that the intestinal tract is functional prior to gestation and could be transporting important nutritive material found in maternal ovarian fluid. C1 HOKKAIDO UNIV,FAC HLTH EDUC,HAKODATE,HOKKAIDO 041,JAPAN. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,HONOLULU,HI 96822. UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. RP CONTE, FP (reprint author), OREGON STATE UNIV,DEPT ZOOL,CORVALLIS,OR 97331, USA. NR 32 TC 7 Z9 7 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 127 EP 133 DI 10.1007/BF02296883 PG 7 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500014 ER PT J AU YOKLAVICH, MM BOEHLERT, GW AF YOKLAVICH, MM BOEHLERT, GW TI UPTAKE AND UTILIZATION OF C-14 GLYCINE BY EMBRYOS OF SEBASTES-MELANOPS SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR DE ROCKFISH; VIVIPARITY; NUTRITION; PISCES; SCORPAENIDAE ID TELEOST CLINUS-SUPERCILIOSUS; MATERNAL-FETAL RELATIONSHIP; VIVIPAROUS TELEOST; ADAPTATIONS; LARVAE; SCORPAENIDAE; PERCIFORMES; ENERGETICS; SCHLEGELI; FISHES AB The ability of embryos of the viviparous scorpaenid Sebastes melanops to take up nutrients from an exogenous substrate was demonstrated by incubating embryos at various stages of development (18-30 days after fertilization) in C-14-labeled glycine for 24 h. Uptake was highest for embryos at the latest stages (28-30 days) and increased at a linear rate during the incubation period. Nutrient uptake was not time dependent in embryos at the early stages (18-22 days). Nutrient utilization by S. melanops embryos was measured by the oxidation of C-14-labeled glycine to (CO2)-C-14. The amount of respired (CO2)-C-14 by the oldest embryos increased significantly at a linear rate over the 24 h incubation period. There was no evidence of nutrient utilization by the youngest embryos. The developmental changes we observed in the uptake and utilization of exogenous glycine are supported by our previous findings that the oldest embryos have fully developed mouths and guts, and require additional nutrition from intraovarian sources at this stage of development. C1 NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,HONOLULU,HI 96822. UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. NR 24 TC 12 Z9 12 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 147 EP 153 DI 10.1007/BF02296885 PG 7 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500016 ER PT J AU SHIMIZU, M KUSAKARI, M YOKLAVICH, MM BOEHLERT, GW YAMADA, J AF SHIMIZU, M KUSAKARI, M YOKLAVICH, MM BOEHLERT, GW YAMADA, J TI ULTRASTRUCTURE OF THE EPIDERMIS AND DIGESTIVE-TRACT IN SEBASTES EMBRYOS, WITH SPECIAL REFERENCE TO THE UPTAKE OF EXOGENOUS NUTRIENTS SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR DE VIVIPARITY; NUTRITION; HORSERADISH PEROXIDASE; RUTHENIUM RED; PINOCYTOSIS; ROCKFISH; PISCES; SCORPAENIDAE ID INTRACELLULAR DIGESTION; HORSERADISH-PEROXIDASE; VIVIPAROUS TELEOST; ENERGETICS; EPITHELIUM; SCHLEGELI; LARVAE; CELLS AB Ultrastructural features of the epidermis and rectum were studied in Sebastes schlegeli and S. melanops during the late stages of embryonic development, to confirm uptake of maternal substances. Ruthenium red (RR) and horseradish peroxidase (HRP) were used at fixation and in live embryos, respectively. Epidermal tissue of embryos after developmental stage 24 comprised two squamous cell layers. The outer, thinner cells and their intercellular spaces were easily infiltrated with RR, but the inner cells had no RR deposition. The HRP was not incorporated into the epidermis except in a few outer cells, which had well-developed microvillous projections of cytoplasm. Sacciform cells, chloride cells, and mucous cells distributed in the inner layer but protruding to the epidermal surface had no intracellular RR and HRP depositions. The rectal cells of embryos at about developmental stage 28 had many globular inclusions containing electron-dense substances. The rectal cells were found to take up and digest HRP actively. It is suggested that the embryonic epidermis is structurally loose and takes up low weight molecules, while rectal cells, after the opening of the mouth, actively ingest exogenous, high weight molecules. C1 HOKKAIDO FISHERIES EXPTL STN,YOICHI,HOKKAIDO 046,JAPAN. OREGON STATE UNIV,COLL OCEANOG,NEWPORT,OR 97365. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,HONOLULU,HI 96822. UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. OREGON STATE UNIV,CTR MARINE SCI,NEWPORT,OR 97365. RP SHIMIZU, M (reprint author), HOKKAIDO UNIV,FAC MINERAL CHEM,HAKODATE,HOKKAIDO 041,JAPAN. NR 18 TC 17 Z9 18 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 155 EP 163 DI 10.1007/BF02296886 PG 9 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500017 ER PT J AU MOSER, HG BOEHLERT, GW AF MOSER, HG BOEHLERT, GW TI ECOLOGY OF PELAGIC LARVAE AND JUVENILES OF THE GENUS SEBASTES SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR DE SCORPAENIDAE; ROCKFISH; DISTRIBUTION; ICHTHYOPLANKTON ID CALIFORNIA CURRENT SYSTEM; SOUTHERN-CALIFORNIA; BAJA-CALIFORNIA; FISH LARVAE; ROCKFISH SCORPAENIDAE; VERTICAL-DISTRIBUTION; FAMILY SCORPAENIDAE; REDFISH SEBASTES; BLACK ROCKFISH; OREGON COAST AB Pelagic larvae and juveniles of the genus Sebastes are widely distributed in the continental shelf and slope waters of subarctic to temperate oceans, with greatest abundance in the Northern Hemisphere. We review the ecology and distribution of these planktonic and micronektonic life stages in relation to oceanographic conditions. Special attention is paid to the west coast of North America, where abundance of larvae from samples collected during 1951-1981 is described. After transformation, the pelagic juveniles are widely distributed, often at great distances from benthic adult habitats. These stages are most frequently distributed in either midwater or near-surface habitats; this dichotomy may require different strategies for successful recruitment. C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,HONOLULU,HI 96822. UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. RP MOSER, HG (reprint author), NATL MARINE FISHERIES SERV,SW FISHERIES CTR,POB 271,LA JOLLA,CA 92038, USA. NR 95 TC 82 Z9 84 U1 3 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 203 EP 224 DI 10.1007/BF02296890 PG 22 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500021 ER PT J AU BOEHLERT, GW LOVE, MS WOURMS, JP YAMADA, J AF BOEHLERT, GW LOVE, MS WOURMS, JP YAMADA, J TI A SUMMARY OF THE SYMPOSIUM ON ROCKFISHES AND RECOMMENDATIONS FOR FUTURE-RESEARCH SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article; Proceedings Paper CT US-JAPAN SYMP ON THE REPRODUCTION AND EARLY LIFE HISTORY IN SEBASTES : ROCKFISHES OF THE GENUS SEBASTES CY JUN, 1989 CL EAST WEST CTR, HONOLULU, HI HO EAST WEST CTR C1 UNIV HAWAII,JOINT INST MARINE & ATMOSPHER RES,HONOLULU,HI 96822. UNIV CALIF SANTA BARBARA,INST MARINE SCI,SANTA BARBARA,CA 93106. CLEMSON UNIV,DEPT BIOL SCI,CLEMSON,SC 29634. HOKKAIDO UNIV,FAC FISHERIES,PHYSIOL & ECOL LAB,HAKODATE,HOKKAIDO 041,JAPAN. RP BOEHLERT, GW (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 4 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JAN PY 1991 VL 30 IS 1-2 BP 273 EP 280 DI 10.1007/BF02296894 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA EU355 UT WOS:A1991EU35500025 ER PT S AU VOAS, J AF VOAS, J BE Vanlansweerde, A Fugetta, A TI A DYNAMIC FAILURE MODEL FOR PREDICTING THE IMPACT THAT A PROGRAM LOCATION HAS ON THE PROGRAM SO ESEC 91 : 3RD EUROPEAN SOFTWARE ENGINEERING CONFERENCE SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Proceedings Paper CT 3RD EUROPEAN SOFTWARE ENGINEERING CONF ( ESEC 91 ) CY OCT 21-24, 1991 CL MILAN, ITALY RP VOAS, J (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 478,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA BERLIN SN 0302-9743 BN 3-540-54742-8 J9 LECT NOTES COMPUT SC PY 1991 VL 550 BP 308 EP 331 PG 24 GA BX63X UT WOS:A1991BX63X00017 ER PT J AU SEDDOUGUI, SO BOWLES, RI SMITH, FT AF SEDDOUGUI, SO BOWLES, RI SMITH, FT TI SURFACE-COOLING EFFECTS ON COMPRESSIBLE BOUNDARY-LAYER INSTABILITY, AND ON UPSTREAM INFLUENCE SO EUROPEAN JOURNAL OF MECHANICS B-FLUIDS LA English DT Article ID TRANSITION; STABILITY AB The influence of surface cooling on compressible boundary-layer instability is discussed theoretically for both viscous and inviscid modes, at high Reynolds numbers, with related questions on upstream influence being considered in an Appendix. The cooling enhances the surface heat transfer and velocity gradient, creating a high-heat-transfer sublayer. This has the effect of distorting and accentuating the viscous Tollmien-Schlichting modes to such an extent that their spatial growth rates becomes comparable with, and can even exceed, the growth rates of inviscid modes, including those found previously. This is for moderate cooling, and it applies at any Mach number. In addition, the moderate cooling destabilizes otherwise stable viscous or inviscid modes, in particular triggering outward-travelling waves at the edge of the boundary layer in the supersonic regime. Severe cooling is also discussed as it brings compressible dynamics directly into play within the viscous sublayer. All the new cooled modes found involve the heat-transfer sublayer quite actively, and they are often multi-structured in form and may be distinct from those observed in previous computational and experimental investigations. The corresponding nonlinear processes are also pointed out with regard to transition in the cooled compressible boundary layer. Finally, comparisons with Lysenko & Maslov's [1984] experiments on surface cooling are presented. C1 UNIV LONDON UNIV COLL,DEPT MATH,LONDON WC1E 6BT,ENGLAND. RP SEDDOUGUI, SO (reprint author), NASA,LANGLEY RES CTR,INST COMP APPL SCI & ENGN,HAMPTON,VA 23665, USA. RI Stephen, Sharon/B-1011-2016 OI Stephen, Sharon/0000-0001-8204-8419 NR 35 TC 16 Z9 16 U1 1 U2 3 PU GAUTHIER-VILLARS PI PARIS PA S P E S-JOURNAL DEPT, 120 BD ST GERMAIN, F-75006 PARIS, FRANCE SN 0997-7546 J9 EUR J MECH B-FLUID JI Eur. J. Mech. B-Fluids PY 1991 VL 10 IS 2 BP 117 EP 145 PG 29 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA FR278 UT WOS:A1991FR27800001 ER PT J AU SULZMAN, FM AF SULZMAN, FM TI NASA PLANS AND OPPORTUNITIES SO EXPERIMENTAL GERONTOLOGY LA English DT Article DE SPACE LIFE SCIENCES; MICROGRAVITY; SPACE MEDICINE; HUMAN RESPONSE TO SPACE FLIGHT; PHYSIOLOGICAL ADAPTATION; SPACE-STATION-FREEDOM AB The NASA Life Sciences program plans an ambitious series of space flight activities throughout the decade of the 1990s. RP SULZMAN, FM (reprint author), NASA,LIFE SUPPORT BRANCH,CODE SBM,600 INDEPENDENCE AVE SW,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0531-5565 J9 EXP GERONTOL JI Exp. Gerontol. PY 1991 VL 26 IS 2-3 BP 131 EP 133 DI 10.1016/0531-5565(91)90003-5 PG 3 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA FR687 UT WOS:A1991FR68700003 PM 1915685 ER PT J AU CHARLES, JB BUNGO, MW AF CHARLES, JB BUNGO, MW TI CARDIOVASCULAR PHYSIOLOGY IN SPACE-FLIGHT SO EXPERIMENTAL GERONTOLOGY LA English DT Article DE CARDIOVASCULAR PHYSIOLOGY; HEADWARD FLUID SHIFT; ORTHOSTATIC TOLERANCE; CENTRAL VENOUS PRESSURE (CVP); SPACE FLIGHT; ECHOCARDIOGRAPHY; WEIGHTLESSNESS; SPACE-SHUTTLE ID VENOUS-PRESSURE; SPACEFLIGHT AB The effects of space flight on the cardiovascular system have been studied since the first manned flights. In several instances, the results from these investigations have directly contradicted the predictions based on established models. Results suggest associations between space flight's effects on other organ systems and those on the cardiovascular system. Such findings provide new insights into normal human physiology. They must also be considered when planning for the safety and efficiency of space flight crewmembers. RP CHARLES, JB (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST SD5,HOUSTON,TX 77058, USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0531-5565 J9 EXP GERONTOL JI Exp. Gerontol. PY 1991 VL 26 IS 2-3 BP 163 EP 168 DI 10.1016/0531-5565(91)90008-A PG 6 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA FR687 UT WOS:A1991FR68700008 PM 1915688 ER PT J AU LEBLANC, A SCHNEIDER, V AF LEBLANC, A SCHNEIDER, V TI CAN THE ADULT SKELETON RECOVER LOST BONE SO EXPERIMENTAL GERONTOLOGY LA English DT Article DE BONE MINERAL DENSITY; BED REST; IMMOBILIZATION; SPACE FLIGHT; EXERCISE ID PROLONGED BED REST; MINERAL-CONTENT; PHYSICAL-ACTIVITY; POSTMENOPAUSAL WOMEN; DISUSE OSTEOPOROSIS; SODIUM-FLUORIDE; BODY-COMPOSITION; COLLES FRACTURE; DISTAL RADIUS; AGED WOMEN AB The loss of bone mineral with aging and subsequent development of osteoporosis is a common problem in elderly women, and as life expectancy increases, in elderly men as well. Space flight also causes bone loss and could be a limiting factor for long duration missions, such as, a Mars expedition or extended occupation of a space station. Before effective countermeasures can be devised, a thorough knowledge of the extent, location, and rate of bone loss during weightlessness is needed from actual space flight data or ground-based disuse models. In addition, the rate and extent that these losses are reversed after return from space flight are of primary importance. Although the mechanisms are not likely to be the same in aging and space flight, there are common elements. For example, strategies developed to prevent disuse bone loss or to enhance the rate of recovery following space flight might have direct applicability to clinical medicine. For various reasons, little attention has been given to recovery of bone mass following space flight. As a prelude to the design of strategies to enhance recovery of bone, this paper reviews published literature related to bone recovery in the adult. We conclude that recovery can be expected, but the rate and extent will be individual and bone site dependent. The development of strategies to encourage or enhance bone formation following space flight may be as important as implementing countermeasures during flight. C1 BAYLOR UNIV,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 97 TC 24 Z9 25 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0531-5565 J9 EXP GERONTOL JI Exp. Gerontol. PY 1991 VL 26 IS 2-3 BP 189 EP 201 DI 10.1016/0531-5565(91)90011-A PG 13 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA FR687 UT WOS:A1991FR68700011 PM 1915690 ER PT J AU HYMER, WC GRINDELAND, RE AF HYMER, WC GRINDELAND, RE TI THE PITUITARY - AGING AND SPACEFLOWN RATS SO EXPERIMENTAL GERONTOLOGY LA English DT Article DE AGING RATS; SPACEFLOWN RATS; GROWTH HORMONE; PITUITARY; SPACEFLIGHT; MICROGRAVITY; BIOASSAYABLE GROWTH HORMONE; IMMUNOASSAYABLE GROWTH HORMONE; TAIL-SUSPENDED RATS ID OLD MALE-RATS; GROWTH-HORMONE; ANTERIOR-PITUITARY; SOMATOMEDIN-C; CELLS; INVITRO; SEPARATION; PROLACTIN; RELEASE; INVIVO AB Decrements in growth hormone (GH) release we observed in two spaceflight experiments and four tail-suspended rat studies mimic age-associated changes in the mammalian pituitary GH system seen by Meites and others. The spaceflight data suggest that formation of high molecular weight bioactive disulfide-linked aggregates of the 20 and 22K monomeric GH forms may be reduced in microgravity, thereby, reducing target tissue activity. Correlative studies to confirm spaceflight as a model for pituitary GH system aging should include: 1) investigation of mechanisms of intracellular hormone packaging, 2) consequences to biological activity of the hormone molecule, and 3) study of intracellular microtubule dynamics. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HYMER, WC (reprint author), PENN STATE UNIV,DEPT MOLEC & CELL BIOL,401 ALTHOUSE LAB,UNIVERSITY PK,PA 16802, USA. NR 25 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0531-5565 J9 EXP GERONTOL JI Exp. Gerontol. PY 1991 VL 26 IS 2-3 BP 257 EP 265 DI 10.1016/0531-5565(91)90018-H PG 9 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA FR687 UT WOS:A1991FR68700018 PM 1915695 ER PT J AU JOHNSON, TE NELSON, GA AF JOHNSON, TE NELSON, GA TI CAENORHABDITIS-ELEGANS - A MODEL SYSTEM FOR SPACE BIOLOGY STUDIES SO EXPERIMENTAL GERONTOLOGY LA English DT Article DE GENETICS; MUTANTS; LONGEVITY; NEMATODES; LIFE-HISTORY TRAITS; SPACE; RADIOBIOLOGY; GRAVITY; FREE-RADICALS; DNA REPAIR; RADIATION; DEVELOPMENT; OXIDATIVE STRESS; AGING ID EMBRYONIC CELL LINEAGES; SENSITIVE MUTANTS; LIFE-SPAN; NEMATODE; RADIATION; GENE; HERMAPHRODITE; MUTAGENESIS; GENOME; LIN-12 AB The utility of the nematode Caenorhabditis elegans in studies spanning aspects of development, aging, and radiobiology is reviewed. These topics are interrelated via cellular and DNA repair processes especially in the context of oxidative stress and free-radical metabolism. The relevance of these research topics to problems in space biology is discussed and properties of the space environment are outlined. Exposure to the space-flight environment can induce rapid changes in living systems that are similar to changes occurring during aging; manipulation of these environmental parameters may represent an experimental strategy for studies of development and senescence. The current and future opportunities for such space-flight experimentation are presented. C1 UNIV COLORADO,DEPT PSYCHOL,BOULDER,CO 80309. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP JOHNSON, TE (reprint author), UNIV COLORADO,INST BEHAV GENET,BOX 447,BOULDER,CO 80309, USA. FU NIA NIH HHS [R01 AG8322, K04 AG00369] NR 58 TC 20 Z9 31 U1 1 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0531-5565 J9 EXP GERONTOL JI Exp. Gerontol. PY 1991 VL 26 IS 2-3 BP 299 EP 309 DI 10.1016/0531-5565(91)90024-G PG 11 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA FR687 UT WOS:A1991FR68700024 PM 1915699 ER PT J AU RASHIDNIA, N BALASUBRAMANIAM, R AF RASHIDNIA, N BALASUBRAMANIAM, R TI THERMOCAPILLARY MIGRATION OF LIQUID DROPLETS IN A TEMPERATURE-GRADIENT IN A DENSITY MATCHED SYSTEM SO EXPERIMENTS IN FLUIDS LA English DT Article ID MARANGONI NUMBERS; BUBBLE; MOTION AB An experimental investigation of thermocapillary flow in droplets of a vegetable oil (partially hydrogenated soybean oil) immersed in silicone oil was conducted in a test cell with a heated top wall and a cooled bottom wall. The liquids are nearly immiscible and have equal densities at a temperature below the room temperature, thus providing a simulation of low-gravity conditions by reducing the buoyancy forces. The interfacial tension between the two oils was measured in the temperature range 20-50-degrees-C using a capillary tube and d-sigma/dT was determined to be negative. Droplets ranging in sizes from 3 mm to 1 cm diameter were injected into the silicone oil. The vertical temperature profile in the bulk liquid (silicone oil) produces temperature variations along the interface which induce variations in the interfacial tension. The flow inside the droplet driven by the resulting interfacial shear stresses was observed using a laser light-sheet flow visualization technique. The flow direction is consistent with the sign of d-sigma/dT. The observed maximum surface velocities are compared to the theoretical predictions of Young et al. (1959). For short times after injection, the droplets were driven by this flow towards the hot wall above the matched-density temperature until the droplets reached a point where the forces due to the flow and buoyancy were equal. After longer times, the droplets moved to the cold side due to suspected density changes caused by mass transfer from the droplets to the silicone oil. This was confirmed by tests under isothermal conditions, where it was observed that droplets of all sizes fell to the cold bottom eventually. Thus, even though the thermocapillary flow inside the droplets persisted for long times in spite of the mass transfer, the migration of droplets towards the hot side was eventually affected by uncontrolled buoyancy forces resulting from density changes due to mass transfer. While additional liquids are being tried, it is suggested from the present experience that reduced gravity experiments will probably be necessary to provide unambiguous data for the migration of droplets. RP RASHIDNIA, N (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 21 TC 14 Z9 15 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PY 1991 VL 11 IS 2-3 BP 167 EP 174 PG 8 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA FM330 UT WOS:A1991FM33000012 ER PT J AU BANDYOPADHYAY, PR WEINSTEIN, LM AF BANDYOPADHYAY, PR WEINSTEIN, LM TI A REFLECTION-TYPE OIL-FILM SKIN-FRICTION METER SO EXPERIMENTS IN FLUIDS LA English DT Article ID TURBULENT BOUNDARY-LAYERS; LASER INTERFEROMETER; FLOW AB Tanner has shown analytically that the slope characteristics of a thin oil-film lying in contact with a surface on which an aerodynamic boundary-layer is developing are explicitly related to the local skin-friction. Unlike many conventional methods of measuring skin-friction, the oil-film method is absolute in nature, requires no calibration and in principle, can be universally applied. In all existing forms of the meter, however, interferometry is used to make measurements of the oil film. In the present contribution, the technique has been simplified by completely eliminating interferometry. This has been achieved by making direct and dynamic measurements of the oil-film slope by directing a reflected beam of light off the top of the oil film to a small position sensing photodiode. The raw data now is very different from that in the interferometric method and consequently, new methods of determining skin-friction from measured oil-film slope histories have been developed. The reflection method has been verified in incompressible flat plate turbulent boundary-layers. The standard of deviation of the measurements is about 10% of the mean. The present version of the meter is compact and simple. RP BANDYOPADHYAY, PR (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 170,HAMPTON,VA 23665, USA. NR 18 TC 9 Z9 9 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PY 1991 VL 11 IS 5 BP 281 EP 292 PG 12 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA GF594 UT WOS:A1991GF59400001 ER PT J AU HOOPER, CL WESTPHAL, RV AF HOOPER, CL WESTPHAL, RV TI HYBRID APPROACH TO DATA REDUCTION FOR MULTISENSOR HOT WIRES SO EXPERIMENTS IN FLUIDS LA English DT Note ID PROBES C1 NASA,AMES RES CTR,STERLING SOFTWARE,MOFFETT FIELD,CA 94035. NASA,AMES RES CTR,ADV AERODYNAM CONCEPTS BRANCH,MOFFETT FIELD,CA 94035. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PY 1991 VL 11 IS 6 BP 398 EP 400 PG 3 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA GM099 UT WOS:A1991GM09900007 ER PT J AU HAMILTON, D KELLEY, K CULBERT, C AF HAMILTON, D KELLEY, K CULBERT, C TI STATE-OF-THE-PRACTICE IN KNOWLEDGE-BASED SYSTEM VERIFICATION AND VALIDATION SO EXPERT SYSTEMS WITH APPLICATIONS LA English DT Article ID EXPERT AB The majority of the work in knowledge-based system verification and validation (KBS V&V) has focused on developing techniques and concepts for performing V&V on expert systems. Little information is available on what V&V practices are currently in use by expert system developers. This article describes the results of a survey whose purpose was to begin documenting some of the experiences and problems KBS developers have encountered. The results of the survey suggest that current practices can be improved and some specific recommendations are included. The recommendations include developing requirements for expert system V&V, addressing common issues, recommending a life cycle for expert systems development, addressing readability and modularity issues, and investigating applicability of analysis tools. C1 NASA,LYNDON B JOHNSON SPACE CTR,SOFTWARE TECHNOL BRANCH PT4,HOUSTON,TX 77058. IBM CORP,DIV SYST INTEGRAT,HOUSTON,TX 77058. NR 7 TC 16 Z9 16 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0957-4174 J9 EXPERT SYST APPL JI Expert Syst. Appl. PY 1991 VL 3 IS 4 BP 403 EP 410 DI 10.1016/0957-4174(91)90167-D PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA GM844 UT WOS:A1991GM84400003 ER PT J AU BEACH, SS GEVARTER, W AF BEACH, SS GEVARTER, W TI STANDARDS FOR EVALUATING EXPERT SYSTEM TOOLS SO EXPERT SYSTEMS WITH APPLICATIONS LA English DT Article AB A brief survey of the literature and proposal for a standard methodology for evaluating expert system building tools are described. Criteria for expert systems environmental factors and expert systems tool features are also discussed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BEACH, SS (reprint author), BEACH ASSOCIATES INC,26 MORENO DR,SANTA CRUZ,CA 95060, USA. NR 28 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0957-4174 J9 EXPERT SYST APPL JI Expert Syst. Appl. PY 1991 VL 2 IS 4 BP 259 EP 267 DI 10.1016/0957-4174(91)90034-C PG 9 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA FK868 UT WOS:A1991FK86800005 ER PT J AU CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG SCHWENKE, DW AF CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG SCHWENKE, DW TI QUANTUM-DYNAMIC CHARACTERIZATION OF REACTIVE TRANSITION-STATES SO FARADAY DISCUSSIONS LA English DT Article ID REACTION PROBABILITIES; COLLINEAR REACTIONS; HYDROGEN MOLECULES; COLLISIONS; H-3 AB It is shown that the accurate quantum-mechanical probability of the reaction of H with H-2, with either zero or one unit of total angular momentum, increases with energy by increments of resolvable 'quanta' of reactive flux. These are analysed in terms of quantized transition states. Bend and stretch quantum numbers are assigned for total angular momentum J equal to zero and for both parities for J = 1 based on an analysis of the density of reactive states. A more detailed description of the reactive scattering process has been obtained by examining the state-selected densities of reactive states, and the initial H + H-2 channels that contribute to the reactive flux passing through specific transition states have been determined. C1 UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP CHATFIELD, DC (reprint author), UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. RI schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 23 TC 60 Z9 61 U1 0 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1364-5498 J9 FARADAY DISCUSS JI Faraday Discuss. PY 1991 VL 91 BP 289 EP 304 DI 10.1039/dc9919100289 PG 16 WC Chemistry, Physical SC Chemistry GA GY597 UT WOS:A1991GY59700021 ER PT J AU PARMAR, DS AF PARMAR, DS TI FERROELECTRIC LIQUID-CRYSTALS AS FLOW-FIELD SENSORS IN BOUNDARY-LAYER INVESTIGATION SO FERROELECTRICS LA English DT Article; Proceedings Paper CT 3RD INTERNATIONAL CONF ON FERROELECTRIC LIQUID CRYSTALS ( FLC-91 ) CY JUN 23-28, 1991 CL BOULDER, CO SP CANON, CHISSO, USA, RES OFF, HOFFMANN LA ROCHE, FERROELECT, FUJITSU LABS, GORDON & BREACH SCI PUBL, HOECHST, IBM, MAT SCI & TECHNOL RP PARMAR, DS (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0015-0193 J9 FERROELECTRICS PY 1991 VL 122 IS 1-4 BP 197 EP 211 DI 10.1080/00150199108226041 PG 15 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA GV775 UT WOS:A1991GV77500018 ER PT J AU DEMARTINI, EE AF DEMARTINI, EE TI ANNUAL VARIATIONS IN FECUNDITY, EGG SIZE, AND THE GONADAL AND SOMATIC CONDITIONS OF QUEENFISH SERIPHUS-POLITUS (SCIAENIDAE) SO FISHERY BULLETIN LA English DT Article ID CLUPEA-HARENGUS-PALLASI; EL-NINO; NORTHERN ANCHOVY; FISH EGGS; GROWTH; FREQUENCY; WEIGHT; CALIFORNIA; HYPOTHESES; ABUNDANCE AB Batch fecundity, weight-specific fecundity (number of eggs per gram somatic weight), size of ripe ovarian eggs, and the somatic and gonadal conditions of adult female queenfish Seriphus politus were estimated for five spawning seasons during an 8-year (1979-86) period. The effects of female somatic weight were evaluated in analyses of covariance comparing batch fecundity, egg size, and gonadal condition among years. Batch fecundity was positively (and allometrically) related to female somatic weight. Fecundities were remarkably similar during four of the five years evaluated. After adjustment for annual differences in female size, fecundities were still significantly lower (by about one-fifth) during 1984, a major El Nino year, compared with the preceding (1979-80) or following (1985-86) pairs of years. Gonadal condition also was uniquely low in 1984. The 1984 declines in fecundity and gonadal condition co-occurred with low somatic condition during 1984, particularly for larger females. Mean size (diameter, dry weight) of eggs was indistinguishable among years. There was a positive relation between egg size and female body size, and a general decline in egg size as the spawning season advanced for females of all sizes. Likely links between declines in fecundity, gonadal and somatic condition, and the crash in planktonic production during the 1982-84 El Nino are discussed. RP DEMARTINI, EE (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 49 TC 24 Z9 27 U1 2 U2 7 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1991 VL 89 IS 1 BP 9 EP 18 PG 10 WC Fisheries SC Fisheries GA FE840 UT WOS:A1991FE84000002 ER PT J AU MATLOCK, GC NELSON, WR JONES, RS GREEN, AW CODY, TJ GUTHERZ, E DOERZBACHER, J AF MATLOCK, GC NELSON, WR JONES, RS GREEN, AW CODY, TJ GUTHERZ, E DOERZBACHER, J TI COMPARISON OF 2 TECHNIQUES FOR ESTIMATING TILEFISH, YELLOWEDGE GROUPER, AND OTHER DEEP-WATER FISH POPULATIONS SO FISHERY BULLETIN LA English DT Article ID HUDSON SUBMARINE-CANYON; LOPHOLATILUS-CHAMAELEONTICEPS; MID-ATLANTIC; ABUNDANCE; GEORGIA; MORTALITY; BEHAVIOR; GROWTH; MEXICO; GULF AB Tilefish Lopholatilus chamaeleonticeps and yellowedge grouper Epinephelus flavolimbatus are deepwater fishes and targets of a relatively recent bottom longline fishery in the Gulf of Mexico. They are long-lived, slow growing, have very limited movements and distribution, and are susceptible to longlines. However, population size and life-history parameter estimates are generally unknown for Gulf fish. This study compared two methods for estimating population sizes to determine the most cost-effective one for use on long-term fishery-independent stock assessments. Bottom longlines were used to deplete fish from a small area, and a regression of catch per effort on cumulative catch was used to estimate the area's population prior to fishing. The population was also estimated by counting fish burrows from a submersible and expanding the mean number per unit area by the study site's area after correcting for the number of occupied burrows. Longlines and submersibles provided significantly different estimates of tilefish populations, the only species for which estimates could be compared. Longline estimates were probably more accurate because errors in area estimation and double counting were evident in submersible data. Longlines were less expensive to operate ($5000 vs. $8000 per day) and they afforded collection of size, age, and sex data on each fish caught. These data were not available from the submersible. Longlines could be used more cost-effectively than submersibles in determining long-term population changes. However, direct observation of fish behavior was not available from longlines, but was from the submersible. Submersibles also provide data on habitat and gear assessment, including deployment, efficiency, bait predation, and potential catch loss during retrieval. C1 NOAA,NATL MARINE FISHERIES SERV,SE FISHERIES SCI CTR,MIAMI,FL 33149. UNIV TEXAS,INST MARINE SCI,PORT ARANSAS,TX 78373. TEXAS PARKS & WILDLIFE DEPT,COASTAL FISHERIES BRANCH,ROCKPORT,TX 78382. NOAA,NATL MARINE FISHERIES SERV,MISSISSIPPI LAB,PASCAGOULA,MS 39567. RP MATLOCK, GC (reprint author), TEXAS PARKS & WILDLIFE DEPT,DIV FISHERIES,4200 SMITH SCH RD,AUSTIN,TX 78744, USA. NR 32 TC 11 Z9 11 U1 3 U2 8 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1991 VL 89 IS 1 BP 91 EP 99 PG 9 WC Fisheries SC Fisheries GA FE840 UT WOS:A1991FE84000010 ER PT J AU POLOVINA, JJ AF POLOVINA, JJ TI EVALUATION OF HATCHERY RELEASES OF JUVENILES TO ENHANCE ROCKFISH STOCKS, WITH APPLICATION TO PACIFIC-OCEAN PERCH SEBASTES-ALUTUS SO FISHERY BULLETIN LA English DT Article AB The equilibrium contribution of hatchery-released juveniles to a rockfish fishery is evaluated by using a yield-per-recruit model. Hatchery-released juveniles may be worth up to an estimated US$0.16 per juvenile to the fishery. The use of hatchery releases to restore a depleted population of Pacific ocean perch Sebastes alutus is examined with the Deriso-Schnute model. This model indicates that hatchery releases have the potential to substantially increase a stock's yield and rate of recovery during the recovery period. RP POLOVINA, JJ (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 15 TC 6 Z9 6 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1991 VL 89 IS 1 BP 129 EP 136 PG 8 WC Fisheries SC Fisheries GA FE840 UT WOS:A1991FE84000013 ER PT J AU SOMERTON, DA AF SOMERTON, DA TI DETECTING DIFFERENCES IN FISH DIETS SO FISHERY BULLETIN LA English DT Article C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. NR 10 TC 11 Z9 13 U1 0 U2 6 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JAN PY 1991 VL 89 IS 1 BP 167 EP 169 PG 3 WC Fisheries SC Fisheries GA FE840 UT WOS:A1991FE84000017 ER PT J AU SCHULZE, NR ROTH, JR AF SCHULZE, NR ROTH, JR TI THE NASA-LEWIS PROGRAM ON FUSION ENERGY FOR SPACE POWER AND PROPULSION, 1958-1978 SO FUSION TECHNOLOGY LA English DT Review ID PLASMA C1 UNIV TENNESSEE,DEPT ELECT & COMP ENGN,KNOXVILLE,TN 37996. RP SCHULZE, NR (reprint author), NASA HEADQUARTERS,WASHINGTON,DC 20546, USA. NR 139 TC 6 Z9 6 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD JAN PY 1991 VL 19 IS 1 BP 11 EP 28 PG 18 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EN210 UT WOS:A1991EN21000001 ER PT J AU VELBEL, MA LONG, DT GOODING, JL AF VELBEL, MA LONG, DT GOODING, JL TI TERRESTRIAL WEATHERING OF ANTARCTIC STONE METEORITES - FORMATION OF MG-CARBONATES ON ORDINARY CHONDRITES SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT WORKSHOP ON DIFFERENCES BETWEEN ANTARCTIC AND NON-ANARCTIC METEORITES CY JUL 27-28, 1989 CL VIENNA, AUSTRIA SP LUNAR & PLANETARY INST, UNIV VIENNA, INST GEOCHEM ID AQUEOUS ALTERATION; VICTORIA LAND; PARENT BODIES; PRODUCTS; GEOCHEMISTRY; EVOLUTION; SALTS AB White efflorescences of weathering origin occur superposed on fusion crusts, or along fractures in the interiors, of approximately 5% of all meteorites in the US Antarctic collection. Efflorescences from equilibrated ordinary chondrites consist of the hydrous Mg-carbonates nesquehonite (+/- hydromagnesite). X-ray diffraction and scanning electron microscope studies of efflorescences from LEW 85320 (H5) show abundant elongate prismatic crystals of nesquehonite (idiomorphic, not pseudomorphous after lansfordite), with minor local encrustations of hydromagnesite. Abundances of Na, K, Ca, and Rb in efflorescences from LEW 85320 suggest that the observed contents of these elements would require only modest fractionation of chondritic composition, whereas extensive fractionation would be required to derive the observed cation ratios from terrestrial sea-salts. Therefore, cations in evaporite minerals on Antarctic meteorites are most likely not products of contamination by terrestrial (marine) salts. The Mg in the efflorescences probably originated from weathering of meteoritic olivine; other cations in the efflorescences are also of meteoritic provenance. Thermodynamic analysis of the reaction forsterite + water + carbon dioxide --> nesquehonite + silica at Antarctic temperatures and pCO2 indicates spontaneity for all water activities greater than 0.65, compatible with the presence of liquid water as brines and/or thin films. C1 MICHIGAN STATE UNIV,DEPT GEOL SCI,E LANSING,MI 48824. NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. NR 60 TC 62 Z9 63 U1 2 U2 10 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 JAN PY 1991 VL 55 IS 1 BP 67 EP 76 DI 10.1016/0016-7037(91)90400-Y PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA EV590 UT WOS:A1991EV59000006 ER PT J AU MITTLEFEHLDT, DW LINDSTROM, MM AF MITTLEFEHLDT, DW LINDSTROM, MM TI GENERATION OF ABNORMAL TRACE-ELEMENT ABUNDANCES IN ANTARCTIC EUCRITES BY WEATHERING PROCESSES SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT WORKSHOP ON DIFFERENCES BETWEEN ANTARCTIC AND NON-ANARCTIC METEORITES CY JUL 27-28, 1989 CL VIENNA, AUSTRIA SP LUNAR & PLANETARY INST, UNIV VIENNA, INST GEOCHEM ID RARE-EARTH ELEMENTS; POLYMICT EUCRITES; PARENT BODY; METEORITES; PETROLOGY; BASALTS; REE; COMPILATION; EVOLUTION; PRODUCTS AB Based on REEs, Antarctic eucrites can be divided into two groups: those showing normal trace element characteristics (e.g., similar to Juvinas) and those showing abnormal trace element abundances. Many Antarctic eucrite, polymict eucrite, and basaltic clast samples show the abnormal trace element abundances with REE patterns exhibiting positive Ce anomalies (sometimes negative Ce anomalies), positive Eu anomalies, and low abundances of the remainder of the REEs, with the LREEs generally being at lower relative abundances than the HREEs. Most samples of crystalline clasts from the polymict eucrites LEW85300, LEW85302, and LEW85303 show that abnormal patterns, while the glassy matrixes of these meteorites show normal patterns. Exterior samples generally show more abnormal patterns (larger anomalies, greater depletions) than interior samples from the same meteorites. Comparison of all basaltic eucrite literature data combined with out data shows that positive and negative Ce anomalies and positive Eu anomalies are found in about 61% of Antarctic eucrite analyses and are virtually unknown in non-Antarctic eucrite analyses. Further, positive Ce anomalies and positive Eu anomalies are commonly associated with Antarctic eucrites having low REE concentrations. Consideration of mineral/melt partition coefficients shows that it is unlikely that Ce anomalies are magmatic features from the HED parent body. Cerium anomalies on earth are generally restricted to the weathering zone where the relative ease of oxidizing Ce to the +4 state allows for fractionation of Ce from the +3 REEs. We believe the unusual REE patterns of abnormal Antarctic eucrites arise from weathering effects generated in or on the Antarctic ice. Our suggested scenario involved formation of melt water and its equilibration with the atmosphere which promotes dissolution of REE-rich phosphates and oxidation of Ce. Tetravalent Ce can then be fractionated from the trivalent REE solution. The details of the weathering process are unclear and will require detailed chemical and SEM investigations of eucrites for their elucidation. We predict that rapidly chilled eucrites with glassy, rather than crystalline, mesostases will be more likely to survive the Antarctic environment without alteration of their REE patterns. Occasional S, Se, and K enrichments are likely to due to weathering in the Antarctic environment as well, but these enrichments are not well correlated with Ce anomalies. C1 NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY MAT BRANCH,HOUSTON,TX 77058. RP MITTLEFEHLDT, DW (reprint author), LOCKHEED ESC,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 50 TC 77 Z9 77 U1 0 U2 6 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 JAN PY 1991 VL 55 IS 1 BP 77 EP 87 DI 10.1016/0016-7037(91)90401-P PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA EV590 UT WOS:A1991EV59000007 ER PT J AU LANGEL, RA AF LANGEL, RA TI RECENT PROGRESS IN ESTIMATING UNCERTAINTY IN GEOMAGNETIC-FIELD MODELING SO GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS LA English DT Article DE GEOMAGNETISM; SPHERICAL HARMONIC ANALYSIS; ERROR ANALYSIS; MATHEMATICAL MODELS ID SECULAR VARIATION; MAGNETIC-FIELD; STOCHASTIC INVERSION; CORE; SPECTRUM; INFERENCE; EPOCH; IGRF RP LANGEL, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,CODE 921,GREENBELT,MD 20771, USA. NR 45 TC 6 Z9 7 U1 0 U2 2 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0309-1929 J9 GEOPHYS ASTRO FLUID JI Geophys. Astrophys. Fluid Dyn. PY 1991 VL 60 IS 1-4 BP 37 EP 88 DI 10.1080/03091929108219996 PG 52 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics GA HX902 UT WOS:A1991HX90200003 ER PT J AU MILLER, TL AF MILLER, TL TI CONVECTION IN A ROTATING, LATERALLY HEATED ANNULUS - TRANSITION TO LOWER SYMMETRY - COMMENT SO GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS LA English DT Note DE HYSTERESIS; BAROCLINIC INSTABILITY; ANNULUS EXPERIMENTS; NUMERICAL MODEL ID BAROCLINIC ANNULUS RP MILLER, TL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV EARTH SCI & APPLICAT,HUNTSVILLE,AL 35812, USA. NR 7 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 0309-1929 J9 GEOPHYS ASTRO FLUID JI Geophys. Astrophys. Fluid Dyn. PY 1991 VL 59 IS 1-4 BP 83 EP 90 DI 10.1080/03091929108227774 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics GA HX901 UT WOS:A1991HX90100004 ER PT J AU YUNG, YL DEMORE, WB PINTO, JP AF YUNG, YL DEMORE, WB PINTO, JP TI ISOTOPIC EXCHANGE BETWEEN CARBON-DIOXIDE AND OZONE VIA O(1D) IN THE STRATOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FAR-INFRARED OBSERVATIONS; HEAVY OZONE; ATMOSPHERIC CO2; ATOM EXCHANGE; FRACTIONATION; OXYGEN; PHOTOCHEMISTRY; O-2; SPECTROSCOPY; DISCHARGE AB We propose a novel mechanism for isotopic exchange between CO2 and O3 via O(1D) + CO2 --> CO3* followed by CO3* --> CO2 + O(3P). A one-dimensional model calculation shows that this mechanism can account for the enrichment in O-18 in the stratospheric CO2 observed by Gamo et al. [1981]. The implications of this mechanism for other stratospheric species and as a source of isotopically heavy CO2 in the troposphere are briefly discussed. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. US EPA,AREAL,RES TRIANGLE PK,NC 27711. RP YUNG, YL (reprint author), CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125, USA. NR 56 TC 87 Z9 89 U1 3 U2 22 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 PY 1991 VL 18 IS 1 BP 13 EP 16 DI 10.1029/90GL02478 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000004 PM 11538378 ER PT J AU TOOHEY, DW BRUNE, WH CHAN, KR ANDERSON, JG AF TOOHEY, DW BRUNE, WH CHAN, KR ANDERSON, JG TI INSITU MEASUREMENTS OF MIDLATITUDE CLO IN WINTER SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB In situ measurements of ClO in the winter lower stratosphere are presented for six flights of the NASA ER-2 aircraft from 38-degrees-N to 61-degrees-N. Enhanced abundances, increasing in severity with date, were observed below 20 km, where HCl and ClONO2 dominate the inorganic chlorine budget. The greatest mixing ratios, over 150 pptv, were encountered on February 20 and 21, 1989, as the vortex experienced a major warming. Although the timing of these ClO enhancements and the evidence that vortex air can reach midlatitudes suggest that heterogeneous conversion of chlorine compounds within the vortex influences chemistry at midlatitudes, the enhancements observed early in the winter could have been caused by unkown chemistry occurring outside the vortex. In either case, photochemical loss of ozone due to catalytic reactions involving ClO at these mixing ratios may be responsible in part for the ozone decreases observed at high latitudes in the northern hemisphere. C1 PENN STATE UNIV,DEPT METEOROL,UNIVERSITY PK,PA 16802. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP TOOHEY, DW (reprint author), HARVARD UNIV,DEPT EARTH & PLANETARY SCI,CAMBRIDGE,MA 02138, USA. RI Toohey, Darin/A-4267-2008 OI Toohey, Darin/0000-0003-2853-1068 NR 9 TC 32 Z9 32 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 JAN PY 1991 VL 18 IS 1 BP 21 EP 24 DI 10.1029/90GL02673 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000006 ER PT J AU DOUGLASS, AR ROOD, RB KAYE, JA STOLARSKI, RS ALLEN, DJ LARSON, EM AF DOUGLASS, AR ROOD, RB KAYE, JA STOLARSKI, RS ALLEN, DJ LARSON, EM TI THE INFLUENCE OF POLAR HETEROGENEOUS PROCESSES ON REACTIVE CHLORINE AT MIDDLE LATITUDES - 3-DIMENSIONAL MODEL IMPLICATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TRANSPORT AB Three dimensional model calculations with the NASA/GSFC chemistry and transport model have been designed to consider the impact of heterogeneous processes occurring on polar stratospheric clouds (PSC's) in the Arctic vortex on the HCl distribution. By examining the HCl concentration for a calculation with PSC's relative to a calculation with gas phase chemistry only, we infer the impact of polar processing on reactive chlorine species at middle latitudes. Results from the chemistry and transport model reproduce basic features of the ClO measurements [Toohey et al., 1991], which were made on the ferry flights of the ER-2 from Stavanger, Norway to Moffett Field, California via Wallops Island, Virginia on February 20 and 21, 1989. The model indicates that perturbed air which is contained within the polar vortex during winter is not homogeneously mixed, and that the ferry flights were made through air with the largest conversion of HCl to reactive chlorine that is seen at middle latitudes. C1 APPL RES CORP, LANDOVER, MD 20985 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHER CHEM & DYNAM BRANCH, LODE 916, GREENBELT, MD 20771 USA. RI Allen, Dale/F-7168-2010; Douglass, Anne/D-4655-2012; Stolarski, Richard/B-8499-2013; Rood, Richard/C-5611-2008 OI Allen, Dale/0000-0003-3305-9669; Stolarski, Richard/0000-0001-8722-4012; Rood, Richard/0000-0002-2310-4262 NR 19 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN PY 1991 VL 18 IS 1 BP 25 EP 28 DI 10.1029/90GL02601 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000007 ER PT J AU KAYE, JA DOUGLASS, AR ROOD, RB STOLARSKI, RS NEWMAN, PA ALLEN, DJ LARSON, EM AF KAYE, JA DOUGLASS, AR ROOD, RB STOLARSKI, RS NEWMAN, PA ALLEN, DJ LARSON, EM TI SPATIAL AND TEMPORAL VARIABILITY OF THE EXTENT OF CHEMICALLY PROCESSED STRATOSPHERIC AIR SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTICA; MODEL AB Simulations of the spatial and temporal variability of the extent of chemically processed air in the Arctic stratosphere have been carried out using a three-dimensional chemistry-transport model for the winters of 1979 and 1989. Chemically processed air is identified in the model as that in which the amounts of hydrogen chloride (HCl) calculated with parameterized loss for conditions appropriate to polar stratospheric cloud (PSC) formation are substantially smaller than those calculated in a model with gas phase chemistry only. It is seen that chemically processed air may be identified over much of the Arctic lower stratosphere from early January to late February, with HCl depletions being larger in 1989 than in 1979. Near the latitude of the Arctic circle, there is important spatial and temporal variability in the extent of chemically processed air. There is some evidence for transport to mid-latitudes of processed air during these winters, but the HCl reductions are much smaller and more sporadic than those near the pole. At 62 and 42N, processed air is calculated to occur preferentially over the longitude regions from 60-120E and 270-330E. C1 UNIV SPACE RES ASSOCIATES,NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD. APPL RES CORP,LANDOVER,MD 20785. RP KAYE, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Allen, Dale/F-7168-2010; Newman, Paul/D-6208-2012; Douglass, Anne/D-4655-2012; Stolarski, Richard/B-8499-2013; Rood, Richard/C-5611-2008 OI Allen, Dale/0000-0003-3305-9669; Newman, Paul/0000-0003-1139-2508; Stolarski, Richard/0000-0001-8722-4012; Rood, Richard/0000-0002-2310-4262 NR 18 TC 15 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN PY 1991 VL 18 IS 1 BP 29 EP 32 DI 10.1029/90GL02597 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000008 ER PT J AU MLYNCZAK, MG SOLOMON, S AF MLYNCZAK, MG SOLOMON, S TI MIDDLE ATMOSPHERE HEATING BY EXOTHERMIC CHEMICAL-REACTIONS INVOLVING ODD-HYDROGEN SPECIES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER THERMOSPHERE; MODEL; MESOSPHERE; DYNAMICS; HYDROXYL AB We calculate the rate of heating that occurs in the middle atmosphere (50 - 105 km) due to four exothermic reactions involving members of the odd-hydrogen family. These reactions are O + OH --> O2 + H, H + O2 + M --> HO2 + M, H + O3 --> OH + O2, and O + HO2 --> OH + O2. The energy lost from vibrationally excited OH (produced in the third reaction) by spontaneous emission is explicitly accounted for by using detailed kinetic models, so that only a portion of the exothermicity of this reaction is converted into heat. The heating rates due to these four reactions are found to rival the oxygen-related heating rates conventionally considered in models of the middle atmosphere, e.g., those due to O + O + M --> O2 + M, O + O2 + M --> O3 + M, O2 + hv --> O + O, and O3 + hv --> O + O2. The conversion of chemical potential energy into molecular translational energy (heat) by these odd-hydrogen reactions is a significant source of energy in the middle atmosphere which has not been previously considered. C1 NOAA,AERON LAB,BOULDER,CO 80303. RP MLYNCZAK, MG (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 401B,HAMPTON,VA 23665, USA. RI Mlynczak, Martin/K-3396-2012 NR 15 TC 69 Z9 69 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN PY 1991 VL 18 IS 1 BP 37 EP 40 DI 10.1029/90GL02672 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000010 ER PT J AU MARSHALL, JA BURCH, JL KAN, JR REIFF, PH SLAVIN, JA AF MARSHALL, JA BURCH, JL KAN, JR REIFF, PH SLAVIN, JA TI SOURCES OF FIELD-ALIGNED CURRENTS IN THE AURORAL PLASMA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ELECTRIC-FIELDS; DISTRIBUTIONS; GENERATION; POTENTIALS; PARTICLE AB Data from the Dynamics Explorer 1 High Altitude Plasma Instrument (HAPI) and magnetometer are used to investigate the sources of field-aligned currents in the nightside auroral zone. It is found that the formula developed by S. Knight predicts the field-aligned current desity fairly accurately in regions where a significant potential drop can be inferred from the HAPI data; there are, however, regions in which the proportionality between potential drop and field-aligned current does not hold. In particular, we note occurrences of strong upward field-aligned current associated not with inverted-V events but instead with suprathermal bursts. In addition, upward field-aligned currents are often observed to peak near the edges of inverted-V events, rather than in the center as would be predicted by Knight. C1 UNIV ALASKA,FAIRBANKS,AK 99775. RICE UNIV,HOUSTON,TX 77251. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP MARSHALL, JA (reprint author), SOUTHWEST RES INST,PO DRAWER 28510,SAN ANTONIO,TX 78228, USA. RI Slavin, James/H-3170-2012; Reiff, Patricia/D-2564-2014 OI Slavin, James/0000-0002-9206-724X; Reiff, Patricia/0000-0002-8043-5682 NR 18 TC 10 Z9 10 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 PY 1991 VL 18 IS 1 BP 45 EP 48 DI 10.1029/90GL02674 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000012 ER PT J AU BURLAGA, LF AF BURLAGA, LF TI MULTIFRACTAL STRUCTURE OF THE INTERPLANETARY MAGNETIC-FIELD - VOYAGER 2 OBSERVATIONS NEAR 25 AU, 1987 - 1988 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LARGE-SCALE FLUCTUATIONS; DIMENSIONS; FRACTALS AB This paper analyzes the large-scale fluctuations of the interplanetary magnetic field strength observed by Voyager 2 from 23.3 AU to 27.8 AU during the period from day 190, 1987 to day 345, 1988. The q-th moments of B-tau show scaling behavior in the range of scales from 16 hours to 21 days for -10 less-than-or-equal-to q less-than-or-equal-to 10, i.e., [B-tau-q] approximately tau-s(q) in this range. s(q) is approximately a quadratic function of q for -4 less-than-or-equal-to q less-than-or-equal-to 4, as one expects for a distribution that is approximately lognormal, but the higher moments diverge from those of a lognormal distribution. The function D(q)(q) = 1 + s(q)/(q - 1) has the form that is characteristic of multifractals. For a multifractal magnetic field, the moments of the field should scale as tau-alpha on a set with fractal dimension f(alpha), where alpha has a continuum of values over some limited range. For the large-scale magnetic field fluctuations, the function f(alpha) computed from D(q)(q) is approximately a fourth order polynomial for -10 less-than-or-equal-to q less-than-or-equal-to 10, and positive values of f(alpha) occur for 0.8 less-than-or-equal-to alpha less-than-or-equal-to 1.2. The multifractal character of the magnetic field strength fluctuations generalizes the concept that the magnetic field is organized into interaction regions (regions in which the magnetic field strength and pressure are higher than average for several hours) and rarefaction regions (regions in which the magnetic field strength and pressure are lower than average). Near solar maximum the interaction regions in the distant heliosphere might be viewed as clusters of strong disturbed fields with considerable fine structure on various scales. The multifractal description of the magnetic field suggests several problems for future study. RP BURLAGA, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 20 TC 102 Z9 102 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN PY 1991 VL 18 IS 1 BP 69 EP 72 DI 10.1029/90GL02596 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EV010 UT WOS:A1991EV01000018 ER PT J AU BLADOS, WR AF BLADOS, WR TI SYMPOSIUM ISSUE ON THE UNITED-STATES AIR-FORCE STINFO PROGRAM - INTRODUCTION SO GOVERNMENT INFORMATION QUARTERLY LA English DT Article RP BLADOS, WR (reprint author), NASA,HEADQUARTERS,CODE NTT,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JAI PRESS INC PI GREENWICH PA 55 OLD POST RD-#2, PO BOX 1678, GREENWICH, CT 06836-1678 SN 0740-624X J9 GOV INFORM Q JI Gov. Inf. Q. PY 1991 VL 8 IS 2 BP 131 EP 133 DI 10.1016/0740-624X(91)90046-B PG 3 WC Information Science & Library Science SC Information Science & Library Science GA FG072 UT WOS:A1991FG07200001 ER PT J AU BLADOS, WR AF BLADOS, WR TI UNITED-STATES AIR-FORCE SCIENTIFIC AND TECHNICAL-INFORMATION PROGRAM - THE STINFO PROGRAM SO GOVERNMENT INFORMATION QUARTERLY LA English DT Article RP BLADOS, WR (reprint author), NASA,HEADQUARTERS,CODE NTT,WASHINGTON,DC 20546, USA. NR 2 TC 1 Z9 1 U1 0 U2 5 PU JAI PRESS INC PI GREENWICH PA 55 OLD POST RD-#2, PO BOX 1678, GREENWICH, CT 06836-1678 SN 0740-624X J9 GOV INFORM Q JI Gov. Inf. Q. PY 1991 VL 8 IS 2 BP 135 EP 153 DI 10.1016/0740-624X(91)90047-C PG 19 WC Information Science & Library Science SC Information Science & Library Science GA FG072 UT WOS:A1991FG07200002 ER PT J AU KUHN, AD AF KUHN, AD TI DEFENSE TECHNICAL-INFORMATION CENTER (DTIC) - ITS ROLE IN THE USAF SCIENTIFIC AND TECHNICAL-INFORMATION PROGRAM SO GOVERNMENT INFORMATION QUARTERLY LA English DT Article RP KUHN, AD (reprint author), NASA,HEADQUARTERS,CODE NTT,WASHINGTON,DC 20546, USA. NR 6 TC 0 Z9 0 U1 0 U2 4 PU JAI PRESS INC PI GREENWICH PA 55 OLD POST RD-#2, PO BOX 1678, GREENWICH, CT 06836-1678 SN 0740-624X J9 GOV INFORM Q JI Gov. Inf. Q. PY 1991 VL 8 IS 2 BP 205 EP 218 DI 10.1016/0740-624X(91)90054-C PG 14 WC Information Science & Library Science SC Information Science & Library Science GA FG072 UT WOS:A1991FG07200009 ER PT J AU PINELLI, TE KENNEDY, JM BARCLAY, RO AF PINELLI, TE KENNEDY, JM BARCLAY, RO TI THE NASA/DOD AEROSPACE KNOWLEDGE DIFFUSION RESEARCH-PROJECT SO GOVERNMENT INFORMATION QUARTERLY LA English DT Article RP PINELLI, TE (reprint author), NASA,LANGLEY RES CTR,MS 180A,HAMPTON,VA 23665, USA. NR 43 TC 10 Z9 10 U1 0 U2 3 PU JAI PRESS INC PI GREENWICH PA 55 OLD POST RD-#2, PO BOX 1678, GREENWICH, CT 06836-1678 SN 0740-624X J9 GOV INFORM Q JI Gov. Inf. Q. PY 1991 VL 8 IS 2 BP 219 EP 233 DI 10.1016/0740-624X(91)90055-D PG 15 WC Information Science & Library Science SC Information Science & Library Science GA FG072 UT WOS:A1991FG07200010 ER PT J AU KUTNER, ML VERTER, F RICKARD, LJ AF KUTNER, ML VERTER, F RICKARD, LJ TI CO(J=2-]1) STUDY OF MOLECULAR CLOUDS IN THE SW ARM OF M31 SO IAU SYMPOSIA LA English DT Article AB We present a map of a 3' x 3' section of the southwest arm of M31 in the CO(J = 2 --> 1) transition. We have detected emission in 25 positions out of 31 observed in a field centered at (-42.5', + 7.5) (major axis, minor axis). The map is sampled at intervals of one beamwidth, with an angular resolution of 30" or 100 x 460 pc. C1 NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. USN, RES LAB, WASHINGTON, DC 20350 USA. RP RENSSELAER POLYTECH INST, DEPT PHYS, TROY, NY 12180 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0074-1809 J9 IAU SYMP PY 1991 IS 146 BP 29 EP 31 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK281 UT WOS:A1991HK28100009 ER PT J AU CHU, YH MACLOW, MM AF CHU, YH MACLOW, MM TI X-RAYS FROM SUPERBUBBLES IN THE LARGE MAGELLANIC CLOUD SO IAU SYMPOSIA LA English DT Article ID EMISSION; NEBULA AB We find diffuse X-ray emission not associated with known SNRs in seven LMC HII complexes. All, except 30 Dor, have simple ring morphologies, indicating shell structures. Assuming these are superbubbles, we find the X-ray luminosity expected from their hot interiors to be an order of magnitude lower than the observed value. SNRs close to the center of a superbubble add very little emission, but we calculate that off-center SNRs hitting the ionized shell could explain the observed emission. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP CHU, YH (reprint author), UNIV ILLINOIS,DEPT ASTRON,1002 W GREEN ST,URBANA,IL 61801, USA. OI Mac Low, Mordecai-Mark/0000-0003-0064-4060 NR 3 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 0074-1809 J9 IAU SYMP PY 1991 IS 148 BP 99 EP 100 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GB201 UT WOS:A1991GB20100019 ER PT J AU VERTER, F AF VERTER, F TI IN SEARCH OF A GALAXY SAMPLE TO STUDY THE SYSTEMATIC PROPERTIES OF CO EMISSION FROM GALAXIES SO IAU SYMPOSIA LA English DT Article ID SPIRAL GALAXIES; STAR FORMATION; LUMINOSITY FUNCTION; IRREGULAR GALAXIES; NEUTRAL HYDROGEN; VIRGO CLUSTER; ATOMIC GAS; RATIO AB Taking the FCRAO Extragalactic CO Survey as an example, the requirements are examined for a galaxy survey which can be used to study the global molecular gas content of normal galaxies as a function of their size and type. The FCRAO survey is applied to derive the CO luminosity function of galaxies, and to look at variations in L(CO)/L(B) and CO/HI with Hubble type. RP NASA, GODDARD SPACE FLIGHT CTR, MAIL CODE 685, GREENBELT, MD 20771 USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0074-1809 J9 IAU SYMP PY 1991 IS 146 BP 137 EP 145 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK281 UT WOS:A1991HK28100041 ER PT J AU FISCHER, P WELCH, DL COTE, P MATEO, M MADORE, BF AF FISCHER, P WELCH, DL COTE, P MATEO, M MADORE, BF TI THE DYNAMICS OF NGC 1866 SO IAU SYMPOSIA LA English DT Article AB High-precision radial velocity measurements have been obtained for 62 stars in the young LMC cluster NGC 1866 using the Las Campanas 2.5m with echelle spectrograph. The mass-weighted mean-square velocity dispersion is sigma-2 = 6.5 +/- 1.3 km2 s-2. The mass of the cluster M(r < 20) = 8.1 +/- 1.6 x 10(4) M., implying a M/L of 0.20 +/- 0.04 in solar units. C1 CARNEGIE INST WASHINGTON,PASADENA,CA 91101. CALTECH,JET PROPULS LAB,PASADENA,CA 91125. RP FISCHER, P (reprint author), MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4M1,ONTARIO,CANADA. 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 0074-1809 J9 IAU SYMP PY 1991 IS 148 BP 200 EP 201 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GB201 UT WOS:A1991GB20100044 ER PT J AU KONTIZAS, E KONTIZAS, M SEDMAK, G SMAREGLIA, R AF KONTIZAS, E KONTIZAS, M SEDMAK, G SMAREGLIA, R TI SHAPES OF MAGELLANIC CLOUD STAR-CLUSTERS SO IAU SYMPOSIA LA English DT Article ID ELLIPTICITIES AB The ellipticities of the most populous MC star clusters (87) have been derived for studying a) ellipticity variations within individual clusters, b) variations of ellipticity distributions for various galaxies, and c) variations of ellipticity of star clusters relative to their dynamical parameters. From the studied clusters it is found that radial ellipticity variations within individual clusters seem to be a common phenomenon for the MC clusters where the inner parts are more elliptical than the outer. The SMC clusters are more elliptical than LMC clusters where ellipticities are measured at r(h). The dynamical masses of the clusters seem to correlate with ellipticities where the most massive are the most elliptical. C1 OSSERV ASTRON TRIESTE,I-34131 TRIESTE,ITALY. RP KONTIZAS, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Kontizas, Evangelos/A-1969-2014 NR 5 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 0074-1809 J9 IAU SYMP PY 1991 IS 148 BP 234 EP 235 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GB201 UT WOS:A1991GB20100060 ER PT J AU SEAQUIST, ER ODEGARD, N AF SEAQUIST, ER ODEGARD, N TI SYNCHROTRON EMISSION AS A TRACER OF THE OUTFLOW IN M82 SO IAU SYMPOSIA LA English DT Article ID STARBURST GALAXIES; IONIZED-GAS; NGC 253; NUCLEUS; RADIO AB We report the discovery of radio synchrotron emission from the outflow in M82. The brightness morphology and radio spectral index distribution add new insights into the physical processes and origin of the wind, which are briefly discussed in this paper. C1 NASA, GODDARD SPACE FLIGHT CTR, GEN SCI CORP, GREENBELT, MD 20771 USA. RP SEAQUIST, ER (reprint author), UNIV TORONTO, DEPT ASTRON, TORONTO M5S 1A1, ONTARIO, CANADA. NR 12 TC 0 Z9 0 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0074-1809 J9 IAU SYMP PY 1991 IS 144 BP 281 EP 285 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK280 UT WOS:A1991HK28000034 ER PT J AU TELESCO, CM CAMPINS, H JOY, M DIETZ, K DECHER, R AF TELESCO, CM CAMPINS, H JOY, M DIETZ, K DECHER, R TI INFRARED IMAGING OF M82 - A STARBURST IN AN EDGE-ON BARRED GALAXY SO IAU SYMPOSIA LA English DT Article C1 UNIV FLORIDA, GAINESVILLE, FL 32611 USA. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, MAIL CODE ES-63, HUNTSVILLE, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0074-1809 J9 IAU SYMP PY 1991 IS 146 BP 284 EP 284 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK281 UT WOS:A1991HK28100087 ER PT J AU TEREBEY, S BEICHMAN, CA GAUTIER, TN HESTER, JJ MYERS, PC VOGEL, SN AF TEREBEY, S BEICHMAN, CA GAUTIER, TN HESTER, JJ MYERS, PC VOGEL, SN TI A SURVEY OF CIRCUMSTELLAR STRUCTURE AROUND YOUNG LOW MASS STARS SO IAU SYMPOSIA LA English DT Article DE INFRARED SOURCES; STARS-ACCRETION; CIRCUMSTELLAR GAS; STAR FORMATION; PREMAIN-SEQUENCE STARS; STELLAR WINDS; BINARIES ID DENSE CORES; DARK CLOUDS AB We present results from a near-infrared array, CO interferometer, and H2O maser interferometer survey of the circumstellar environments of 26 young low-luminosity embedded stars located in nearby molecular clouds. About 75% of the sample show evidence for stellar winds/outflows in the near-infrared or CO data indicating that most of these sources are in the early wind clearing phase of their evolution. Close to 15% are multiple on the scale of 20", suggesting that fragmentation of their surrounding dense cloud cores is important before or during gravitational collapse. Roughly 10% have H2O maser emission and the kinematics imply the masers arise in gravitationally unbound gas (i.e., a stellar wind or outflow) rather than in a circumstellar disk. C1 CALTECH,PALOMAR OBSERV,PASADENA,CA 91125. CALTECH,JET PROPULS LAB,PASADENA,CA 91125. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV MARYLAND,MET & CERAM PROGRAM,COLLEGE PK,MD 20742. RP TEREBEY, S (reprint author), CALTECH,CTR INFRARED PROC & ANAL,MS 100-22,PASADENA,CA 91125, USA. NR 11 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 0074-1809 J9 IAU SYMP PY 1991 IS 147 BP 345 EP 352 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GE121 UT WOS:A1991GE12100036 ER PT J AU JONES, FC AF JONES, FC TI STATIC VERSUS DYNAMIC COSMIC-RAY HALOS SO IAU SYMPOSIA LA English DT Article ID GALAXY AB The dynamical halo of the Galaxy offers a natural explanation for the form of the variation of cosmic-ray path length with energy. The variation above 1 GeV per nucleon can be understood as due to the variation of the diffusion coefficient, and hence the resident time in the galaxy, with energy. The flattening of the curve below 1 GeV per nucleon is seen to mark a transition to a convection dominated regime where the variation of the diffusion coefficient is no longer a determining factor. It is possible that the random motion of the cosmic rays about the galaxy that prevents us from seeing their sources in a clear manner may enable us to extract information about the galaxy at large and learn something about its large scale motions. RP JONES, FC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, CODE 665, GREENBELT, MD 20771 USA. NR 24 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0074-1809 J9 IAU SYMP PY 1991 IS 144 BP 359 EP 368 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK280 UT WOS:A1991HK28000047 ER PT J AU WELCH, DL COTE, P MATEO, M MADORE, BF AF WELCH, DL COTE, P MATEO, M MADORE, BF TI THE VARIABLE-STAR POPULATION OF NGC-1866 SO IAU SYMPOSIA LA English DT Article ID LMC CLUSTER NGC-1866 AB We report the results of an extensive photometric and radial velocity study of the variable stars in the Large Magellanic Cloud (LMC) cluster NGC 1866. We find: 1) twenty probable member Cepheid variables, 2) V lightcurve amplitude decreasing toward the red edge, 3) lightcurves, periods, and memberships for Storm-type variables, 4) one apparently stable star in the instability strip, 5) an overtone pulsator in the fundamental region of the strip, 6) a single-lined spectroscopic binary member Cepheid, 7) an essentially dispersionless P-L-C with beta = 2.0 +/- 0.4, 8) at least one red supergiant variable of long period, and 9) a true distance modulus of 18.57 +/- 0.01 mag for the cluster. C1 CALTECH,JET PROPULS LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91109. RP WELCH, DL (reprint author), MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4M1,ONTARIO,CANADA. NR 5 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 0074-1809 J9 IAU SYMP PY 1991 IS 148 BP 384 EP 385 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GB201 UT WOS:A1991GB20100103 ER PT J AU FREEDMAN, WL MADORE, BF AF FREEDMAN, WL MADORE, BF TI METALLICITY EFFECTS ON THE CEPHEID DISTANCE SCALE SO IAU SYMPOSIA LA English DT Article AB We are undertaking empirical tests for the effects of metallicity on the zero-point of the Period-Luminosity relations for Cepheids in M31 and in the Small Magellanic Cloud (SMC), as compared to the Large Magellanic Cloud (LMC). For M31 we have used BVRI data on comparable sets of Cepheids in three radially separated, and chemically different, fields in order to solve simultaneously for the reddenings and the true distance moduli to each of these fields. Recent theory predicts that the reddening-corrected moduli should differ by 0.8 mag given the observed metallicity range in our M31 Cepheid sample; we observe a maximum range of only 0.17 mag. For the SMC BVRIJHK data, treated in a similar fashion, the predicted theoretical effects on the short wavelength (B and V) data may be visible, but with low statistical certainty and at a reduced amplitude with respect to the predictions. C1 CALTECH,UPL,NASA IPAC EXTRAGALACT DATABASE,PASADENA,CA 91125. RP FREEDMAN, WL (reprint author), OBSERV CARNEGIE INST WASHINGTON,PASADENA,CA, USA. NR 4 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 0074-1809 J9 IAU SYMP PY 1991 IS 148 BP 471 EP 472 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA GB201 UT WOS:A1991GB20100124 ER PT J AU CRUIKSHANK, DP THOLEN, DJ HARTMANN, WK BELL, JF BROWN, RH AF CRUIKSHANK, DP THOLEN, DJ HARTMANN, WK BELL, JF BROWN, RH TI 3 BASALTIC EARTH-APPROACHING ASTEROIDS AND THE SOURCE OF THE BASALTIC METEORITES SO ICARUS LA English DT Article ID SPECTRAL REFLECTANCE; SURFACE MATERIALS; SOLAR-SYSTEM; 4 VESTA; FRAGMENTATION; SATELLITES; PYROXENES; MIXTURES; OLIVINE C1 PLANETARY SCI INST,TUCSON,AZ 85719. UNIV HAWAII,HAWAII INST GEOPHYS,DIV PLANETARY GEOSCI,HONOLULU,HI 96822. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. RP CRUIKSHANK, DP (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 58 TC 97 Z9 98 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 JAN PY 1991 VL 89 IS 1 BP 1 EP 13 DI 10.1016/0019-1035(91)90083-6 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU840 UT WOS:A1991EU84000001 ER PT J AU COUSTENIS, A BEZARD, B GAUTIER, D MARTEN, A SAMUELSON, R AF COUSTENIS, A BEZARD, B GAUTIER, D MARTEN, A SAMUELSON, R TI TITANS ATMOSPHERE FROM VOYAGER INFRARED OBSERVATIONS .3. VERTICAL DISTRIBUTIONS OF HYDROCARBONS AND NITRILES NEAR TITANS NORTH-POLE SO ICARUS LA English DT Article ID RADIO-OCCULTATION; CARBON-MONOXIDE; PHOTOCHEMISTRY; DIACETYLENE; ABUNDANCE; BAND C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP COUSTENIS, A (reprint author), OBSERV PARIS,DEPT RECH SPATIALE,MEUDON SECT,F-92195 MEUDON,FRANCE. NR 27 TC 141 Z9 141 U1 1 U2 14 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 JAN PY 1991 VL 89 IS 1 BP 152 EP 167 DI 10.1016/0019-1035(91)90095-B PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU840 UT WOS:A1991EU84000013 ER PT J AU WEISSMAN, PR AF WEISSMAN, PR TI THE ANGULAR-MOMENTUM OF THE OORT CLOUD SO ICARUS LA English DT Note ID COMET SHOWERS RP WEISSMAN, PR (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 21 TC 10 Z9 10 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 JAN PY 1991 VL 89 IS 1 BP 190 EP 193 DI 10.1016/0019-1035(91)90097-D PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU840 UT WOS:A1991EU84000015 ER PT J AU SHIEH, LS ZHAO, XM SUNKEL, JW AF SHIEH, LS ZHAO, XM SUNKEL, JW TI HYBRID STATE-SPACE SELF-TUNING CONTROL USING DUAL-RATE SAMPLING SO IEE PROCEEDINGS-D CONTROL THEORY AND APPLICATIONS LA English DT Article DE DIGITAL REDESIGN; DUAL-RATE SAMPLING; OPTIMAL REGULATORS; POLE ASSIGNMENT; PSEUDO-HYBRID SYSTEM; STATE-SPACE SELF-TUNING CONTROL ID SYSTEMS; REGULATORS; EQUATIONS; ROOT AB This paper presents a hybrid state-space self-tuning control scheme using dual-rate sampling for suboptimal digital adaptive control of linear time-invariant continuous-time multivariable stochastic systems with unknown parameters. An equivalent fast-rate discrete-time state-space innovation model (with estimated states) of the continuous-time system is constructed by using the estimated system parameters and Kalman gain. To utilise the existing optimal regional-pole assignment method developed in the continuous-time domain, the constructed fast-rate discrete-time model is converted into an equivalent continuous-time model for the development of a state-feedback optimal control law with pole placement in a specific region. The developed analogue optimal control law is then converted into an equivalent pseudo-slow-rate digital control law via the proposed digital redesign technique, which can be realised via slow-rate digital electronics. The proposed method enables the development of a digitally implementable advanced control algorithm for digital adaptive control of continuous-time multivariable stochastic systems which may be unstable and/or have nonminimum phase. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP SHIEH, LS (reprint author), UNIV HOUSTON,DEPT ELECT ENGN,HOUSTON,TX 77204, USA. NR 21 TC 14 Z9 14 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0143-7054 J9 IEE PROC-D PD JAN PY 1991 VL 138 IS 1 BP 50 EP 58 PG 9 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EU141 UT WOS:A1991EU14100007 ER PT J AU REINATH, MS AF REINATH, MS TI A LONG-RANGE LASER VELOCIMETER SO IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS LA English DT Article ID SYSTEM AB A long-range laser velocimeter (LV) developed for remote operation from within the flow fields of the large wind tunnels of the National Full-Scale Aerodynamics Complex is described. Emphasis is placed on recent improvements in optical hardware as well as recent additions to data acquisition and processing techniques. The method used for data reduction of photon resolved signals is outlined in detail, and a discussion of measurement accuracy is made. To study the performance of the LV and verify the measurement accuracy, laboratory measurements were made in the flow field of a 10 cm diameter, 30 m/s axisymmetric jet. The measured velocity and turbulence intensity surveys are compared with measurements made with a hot-wire anemometer. Additionally, the LV was used during the flow calibration of the 80 by 120 ft wind tunnel to measure the test-section boundary-layer thickness at the maximum wind tunnel speed of 51.5 m/s. A discussion of the requirements and techniques used to seed the flow is made, and boundary-layer surveys of mean velocity and turbulence intensity of the streamwise component and the component normal to the surface are presented. The streamwise component of mean velocity is compared with data obtained with a total pressure rake. RP REINATH, MS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 20 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 0018-9251 J9 IEEE T AERO ELEC SYS JI IEEE Trans. Aerosp. Electron. Syst. PD JAN PY 1991 VL 27 IS 1 BP 125 EP 138 DI 10.1109/7.68155 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA EY693 UT WOS:A1991EY69300014 ER PT J AU SIEGEL, PH DENGLER, RJ AF SIEGEL, PH DENGLER, RJ TI THE DIELECTRIC-FILLED PARABOLA - A NEW MILLIMETER SUBMILLIMETER WAVELENGTH RECEIVER TRANSMITTER FRONT END SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID ANTENNAS; MIXER AB A design is presented for a semi-integrated millimeter/sub-millimeter wavelength receiver/transmitter front end incorporating a planar antenna and a solid-state device in an efficient feed structure which can be matched directly to high f-number optical systems. The new feed system combines the simplicity and robustness of a dielectric substrate lens with the high gain of a parabolic reflector in a single structure that we have termed a dielectric-filled parabola. The same fundamental unit can be configured as either a heterodyne or direct detection mode receiver, a power transmitter or a frequency multiplier by changing out the solid-state device and/or the integrated antenna. The structure can also be used with a small integrated antenna array in a multibeam or imaging arrangement. In the first part of the paper, design and fabrication details for the new feed system are given. These are followed by beam pattern and impedance measurements taken on a microwave model when dipole, bow-tie, log-periodic and log-spiral antennas are used as the integrated feed elements. RP SIEGEL, PH (reprint author), CALTECH,JET PROP LAB,ADV DEVICES GRP,PASADENA,CA 91109, USA. NR 22 TC 16 Z9 16 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JAN PY 1991 VL 39 IS 1 BP 40 EP 47 DI 10.1109/8.64433 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA EQ581 UT WOS:A1991EQ58100007 ER PT J AU ROCKEN, C JOHNSON, JM NEILAN, RE CEREZO, M JORDAN, JR FALLS, MJ NELSON, LD WARE, RH HAYES, M AF ROCKEN, C JOHNSON, JM NEILAN, RE CEREZO, M JORDAN, JR FALLS, MJ NELSON, LD WARE, RH HAYES, M TI THE MEASUREMENT OF ATMOSPHERIC WATER-VAPOR - RADIOMETER COMPARISON AND SPATIAL VARIATIONS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID GLOBAL POSITIONING SYSTEM; BASELINE; INTERFEROMETRY; LENGTH; DELAY AB We conducted two water vapor radiometer (WVR) experiments to evaluate whether such instruments are both suitable and needed to correct for propagation effects that are induced by precipitable water vapor (PWV) on signals from the Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI). WVR's are suitable for these corrections if they provide wet path delays to better than 0.5 cm. They are needed if spatial variations of PWV result in complicated, direction-dependent propagation effects that are too complex to be parametrized in the GPS or VLBI geodetic solution. In the first experiment we addressed the suitability of radiometers by comparing six WVR's at Stapleton International Airport in Denver, Colorado, for two weeks. While two WVR's showed an average wet path delay bias of only 0.1 cm, others were biased by 1-3 cm relative to each other and relative to radiosondes. The second experiment addressed the question whether radiometers are needed for the detection of inhomogeneities in the wet delay. Three JPL D-series radiometers were operated at three sites in Colorado approximately 50-km apart. The WVR's simultaneously sampled PWV at different azimuths and elevations in search of spatial variations of PWV. On one day of this second experiment we found evidence for spatial variations of the wet path delay as high as 20% of the total wet path delay. C1 UNIV COLORADO,COLORADO CTR ASTRODYNAM RES,BOULDER,CO 80309. CALTECH,JET PROP LAB,PASADENA,CA 91109. NOAA,ENVIRONM RES LABS,BOULDER,CO 80303. RADIOMETR CORP,BOULDER,CO 80301. NASA,GODDARD SPACE FLIGHT CTR,INTERFEROMETR INC,GREENBELT,MD 20771. RP ROCKEN, C (reprint author), UNIV COLORADO,UNIV NAVSTAR CONSORTIUM,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80309, USA. NR 24 TC 21 Z9 21 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 3 EP 8 DI 10.1109/36.103286 PG 6 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900001 ER PT J AU SHIMABUKURO, YE SMITH, JA AF SHIMABUKURO, YE SMITH, JA TI THE LEAST-SQUARES MIXING MODELS TO GENERATE FRACTION IMAGES DERIVED FROM REMOTE-SENSING MULTISPECTRAL DATA SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID LANDSAT AB The remote sensing instrumentation measures the spectral radiance reflected or emitted within its instantaneous field of view (IFOV). At target level, this means to sense the spectral radiance reflected or emitted by a finite target area (pixel). The pixel size in present-day remote sensing systems is large enough to include different types of land cover. The Constrained Least Squares (CLS) and Weighted Least Squares (WLS) mixing models to generate fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related to the observed variation in forest structure; i.e., the fraction of inferred shade in the pixel is related to different eucalyptus ages. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SHIMABUKURO, YE (reprint author), INST PESQUISAS ESPACIAIS,AV ASTRONAUTAS 1758,BR-12201 SAO JOSE CAMPOS,SP,BRAZIL. NR 13 TC 329 Z9 361 U1 1 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 16 EP 20 DI 10.1109/36.103288 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900003 ER PT J AU LIVINGSTONE, CE DRINKWATER, MR AF LIVINGSTONE, CE DRINKWATER, MR TI SPRINGTIME C-BAND SAR BACKSCATTER SIGNATURES OF LABRADOR SEA MARGINAL ICE - MEASUREMENTS VERSUS MODELING PREDICTIONS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SNOW; ZONE AB During the March 1987 Labrador Ice Margin Experiment (LIMEX '87) two independent investigations were conducted to determine the C-band backscattering cross section of the marginal pack ice along the Newfoundland coast. In one experiment, data from a recently calibrated C-band airborne scatterometer were combined with C-band synthetic aperture radar (SAR) data to measure the normalized scattering cross section of the ice from 10-degrees to 74-degrees incidence angle to within +/- 2 dB. In the other experiment, detailed measurements of ice surface roughness and surface properties were made and the radar cross sections were predicted from a scattering model. This paper combines measured and model results and shows them to be fully compatible. By extension, this study is expected to apply to any rubbled sea-ice surface when surface scattering dominates. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP LIVINGSTONE, CE (reprint author), CANADA CTR REMOTE SENSING,2464 SHEFFIELD RD,OTTAWA K1A OY7,ONTARIO,CANADA. RI Drinkwater, Mark/C-2478-2011 OI Drinkwater, Mark/0000-0002-9250-3806 NR 23 TC 34 Z9 34 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 29 EP 41 DI 10.1109/36.103290 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900005 ER PT J AU IRONS, JR RANSON, KJ WILLIAMS, DL IRISH, RR HUEGEL, FG AF IRONS, JR RANSON, KJ WILLIAMS, DL IRISH, RR HUEGEL, FG TI AN OFF-NADIR-POINTING IMAGING SPECTRORADIOMETER FOR TERRESTRIAL ECOSYSTEM STUDIES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID REFLECTANCE FACTOR DISTRIBUTIONS; VEGETATION CANOPIES; SPECTRAL RESPONSE; ANISOTROPY; DYNAMICS; SURFACES; SENSOR; VIEW; EOS AB The Advanced Solid-State Array Spectroradiometer (ASAS) is an airborne, off-nadir-pointing imaging spectroradiometer used to acquire bidirectional radiance data for terrestrial targets. As its platform aircraft flies over a target, the sensor can image the target through a sequence of at least seven fore-to-aft view directions ranging up to 45-degrees on either side of nadir. ASAS acquires data for 29 spectral bands in the visible and near-infrared portions of the spectrum (465 to 871 nm) with a resolution of 15 nm. The basic ASAS data product is a sequence of digital images acquired from multiple view directions and consisting of calibrated spectral radiance values. Examples of ASAS data acquired for recent field experiments are presented. The data demonstrate the combined effects of reflectance anisotropy and increased atmospheric path length on off-nadir observations. One result of these effects is a variation in vegetation indices as a function of view direction. Normalized-difference-vegetation-indices for prairie grass, coniferous forest, and deciduous forest canopies varied up to 14, 23, and 6%, respectively, relative to the nadir as a function of view zenith angle along the solar principal plane. These ASAS data are comparable to data anticipated from several sensors proposed for the Earth Observing System. C1 ST SYST CORP,LANHAM,MD 20706. NASA,GODDARD SPACE FLIGHT CTR,INSTRUMENT SYST BRANCH,GREENBELT,MD 20771. RP IRONS, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771, USA. RI Irons, James/D-8535-2012; Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 26 TC 88 Z9 90 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 66 EP 74 DI 10.1109/36.103294 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900009 ER PT J AU ARDANUY, PE HAN, D SALOMONSON, VV AF ARDANUY, PE HAN, D SALOMONSON, VV TI THE MODERATE RESOLUTION IMAGING SPECTROMETER (MODIS) SCIENCE AND DATA SYSTEM REQUIREMENTS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID EARTH AB The Moderate Resolution Imaging Spectrometer (MODIS) has been designated as a facility instrument on the first NASA polar orbiting platform as part of the Earth Observing System (EOS), and is scheduled for launch in the late 1990's. The near global daily coverage of MODIS, combined with its continuous operation, broad spectral coverage, and relatively high spatial resolution, makes it central to the objectives of EOS. The mission requirements of the EOS and the MODIS instruments may be traced through the MODIS science team members to the proposed set of core MODIS data products. The development, implementation, production, and validation of these core data products define a set of functional, performance, and operational requirements on the data system that operate between the sensor measurements and the data products supplied to the user community. In this paper, we review the science requirements guiding the processing of MODIS data, and we discuss some aspects of an operations concept for the production of data products from MODIS for use by the scientific community. C1 NASA,GODDARD SPACE FLIGHT CTR,EARTH SCI DIRECTORATE,GREENBELT,MD 20771. RP ARDANUY, PE (reprint author), RES & DATA SYST CORP,GREENBELT,MD 20771, USA. NR 13 TC 30 Z9 30 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 75 EP 88 DI 10.1109/36.103295 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900010 ER PT J AU GLAZMAN, RE AF GLAZMAN, RE TI STATISTICAL PROBLEMS OF WIND-GENERATED GRAVITY-WAVES ARISING IN MICROWAVE REMOTE-SENSING OF SURFACE WINDS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SEA-SURFACE; ATMOSPHERIC STABILITY; EQUILIBRIUM RANGE; SPEED; OCEAN; MODEL; SCATTEROMETRY; SCATTERING; GEOMETRY; SPECTRA AB The basic geometric features of a developed sea surface affecting the accuracy of wind speed measurements by satellite instruments are reviewed. Based on Seasat scatterometer, Geosat altimeter and DMSP-SSM/I (Defense Meteorological Satellite Program-Special Sensor Microwave/Imager) observations collocated with buoy data, error trends in the satellite winds are shown to be correlated with various measures of wave development. These trends are explained by examining the rms wave slope of energy-containing waves which, directly or indirectly, affects all microwave techniques. For a developed sea, the influence of the equilibrium range parameters characterizing the spectrum of wind-generated waves (i.e., the exponent in the power law, the generalized "Phillips constant," and the high- and low-frequency cutoffs) on the wave slope is quantified. Furthermore, statistics of temporal-spatial rates of steep and breaking waves (affecting the scatterometer and radiometer measurements) are derived and compared with field observations. Fluctuations in the actual number of steep wavelet events occurring within a finite surface area are shown to be an important factor of the radar backscatter if the surface area (i.e., the resolution cell) is much smaller than 1 km2. The inner scale of the equilibrium range appearing due to energy dissipation by breaking waves is highlighted as a major factor in determining a surface's statistical geometry and hence its microwave returns for all satellite sensors. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 34 TC 14 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 135 EP 142 DI 10.1109/36.103303 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900018 ER PT J AU GIOVANANGELI, JP BLIVEN, LF LECALVE, O AF GIOVANANGELI, JP BLIVEN, LF LECALVE, O TI A WIND-WAVE TANK STUDY OF THE AZIMUTHAL RESPONSE OF A KA-BAND SCATTEROMETER SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID VECTOR AB The azimuthal response of a 36-GHz scatterometer from wind-generated waves in large wave tanks is presented. The radar was operated at an incidence angle of 30-degrees from nadir and with vertical polarization. Measurements were also made of turbulent stress in air flow above the water surface and the cross-wind and along-wind wave slopes. Friction velocity u* ranged from 5 to 100 cm/s. For each wind speed, the azimuthal variation of radar cross section is expressed in terms of the classical three-term Fourier cosine series. As the wind speed increases, the azimuthally averaged radar cross section increases, and the upwind-downwind asymmetry decreases, in general agreement with field observations. However, this Ka-band data set reveals that the cross-wind modulation is not a monotonic function of windspeed, but instead it reaches a peak at u* of about 25 cm/s. The wave slope data exhibit a similar feature in the short wave directional development. Finally, measurements from 35- and 95-m fetches indicate that the azimuthal response of the radar is more directly related to wind stress than wind speed. C1 NASA, GODDARD SPACE FLIGHT CTR, WALLOPS ISL, VA 23337 USA. RP INST MECAN STAT TURBULENCE, 12 AVE GENERAL LECLERC, F-13003 MARSEILLE, FRANCE. RI bliven, francis/E-1450-2012 NR 13 TC 14 Z9 14 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 143 EP 148 DI 10.1109/36.103304 PG 6 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900019 ER PT J AU SHAFFER, SJ DUNBAR, RS HSIAO, SV LONG, DG AF SHAFFER, SJ DUNBAR, RS HSIAO, SV LONG, DG TI A MEDIAN-FILTER-BASED AMBIGUITY REMOVAL ALGORITHM FOR NSCAT SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SEASAT SCATTEROMETER; WIND AB The NASA Scatterometer, NSCAT, is an active spaceborne radar designed to measure the normalized radar backscatter coefficient sigma-0 of the ocean surface. These measurements can, in turn, be used to infer the surface vector wind over the ocean using a geophysical model function. Because of the nature of the model function, several ambiguous wind vectors result. A process commonly known as "dealiasing" or ambiguity removal must be used to select the "best" wind vector from the set of ambiguous wind vectors. An automated, median-filter-based ambiguity removal algorithm which requires only the scatterometer measurements will be used by the NSCAT ground data-processing system. The algorithm incorporates a number of selectable parameters such as window size, mode, and likelihood weighting which can be adjusted to optimize algorithm performance. This paper describes the baseline NSCAT ambiguity removal algorithm and the method used to select the set of optimum parameter values. An extensive simulation of the NSCAT instrument and ground data processor provides a means of testing the resulting "turned" algorithm. This simulation generates the ambiguous wind-field vectors expected from the instrument as it orbits over a set of realistic mesoscale wind fields. The ambiguous wind field is then dealiased using the median-filter-based ambiguity removal algorithm. Performance is measured by comparison of the selected wind fields with the "true" wind fields. Results have shown that this median-filter-based ambiguity removal algorithm satisfies NSCAT mission requirements, and it therefore has been incorporated into the baseline geophysical data-processing system for NSCAT. RP SHAFFER, SJ (reprint author), CALTECH,JET PROP LAB,RADAR SCI & ENGN SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 11 TC 77 Z9 88 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JAN PY 1991 VL 29 IS 1 BP 167 EP 174 DI 10.1109/36.103307 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA ER649 UT WOS:A1991ER64900022 ER PT J AU GAIER, JR GOODEN, CE YASHAN, D NAUD, S AF GAIER, JR GOODEN, CE YASHAN, D NAUD, S TI THE PRELIMINARY FEASIBILITY OF INTERCALATED GRAPHITE RAILGUN ARMATURES SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 5TH SYMP ON ELECTROMAGNETIC LAUNCHER TECHNOLOGY CY APR 03-05, 1990 CL SANDESTIN, FL ID FIBERS AB Graphite intercalation compounds may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite. C1 AIR FORCE ARMAMENT LAB,SAH,EGLIN AFB,FL 32542. CLEVELAND STATE UNIV,CLEVELAND,OH 44115. NAVAL COASTAL SYST LAB,PANAMA CITY,FL 32407. RP GAIER, JR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 6 TC 0 Z9 0 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 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JAN PY 1991 VL 27 IS 1 BP 289 EP 293 DI 10.1109/20.101042 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA ER831 UT WOS:A1991ER83100059 ER PT J AU ELLIOTT, DG AF ELLIOTT, DG TI TRAVELING-WAVE SYNCHRONOUS COIL GUN SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 5TH SYMP ON ELECTROMAGNETIC LAUNCHER TECHNOLOGY CY APR 03-05, 1990 CL SANDESTIN, FL AB A traveling-wave synchronous coil gun permits independent adjustment of the magnetic field and armature current for high velocity at low armature mass fraction. Magnetic field energy is transferred from the rear of the wave to the front without passing through the power supply. Elaborate switching is required. RP ELLIOTT, DG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 1 TC 1 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JAN PY 1991 VL 27 IS 1 BP 647 EP 649 DI 10.1109/20.101111 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA ER831 UT WOS:A1991ER83100128 ER PT J AU SEDDOUGUI, SO BASSOM, AP AF SEDDOUGUI, SO BASSOM, AP TI ON THE INSTABILITY OF GORTLER VORTICES TO NONLINEAR TRAVELING WAVES SO IMA JOURNAL OF APPLIED MATHEMATICS LA English DT Article ID GROWING BOUNDARY-LAYERS AB Recent theoretical work by Hall & Seddougui (1989) has shown that strongly nonlinear high-wavenumber Gortler vortices developing within a boundary layer flow are susceptible to a secondary instability which takes the form of travelling waves confined to a thin region centred at the outer edge of the vortex. This work considered the case in which the secondary mode could be satisfactorily described by a linear stability theory, and in the current paper our objective is to extend this investigation of Hall & Seddougui (1989) into the nonlinear regime. We find that, at this stage, not only does the secondary mode become nonlinear, but it also interacts with itself so as to modify the governing equations for the primary Gortler vortex. In this case, then, the vortex and the travelling wave drive each other, and indeed the whole flow structure is described by an infinite set of coupled nonlinear differential equations. We undertake a Stuart-Watson type of weakly nonlinear analysis of these equations and conclude, in particular, that on this basis there exist stable flow configurations in which the travelling mode is of finite amplitude. Implications of our findings for practical situations are discussed, and it is shown that the theoretical conclusions drawn here are in good qualitative agreement with available experimental observations. C1 UNIV EXETER,DEPT MATH,N PK RD,EXETER EX4 4QE,DEVON,ENGLAND. NASA,LANGLEY RES CTR,INST COMP APPLICAT & SCI ENGN,HAMPTON,VA 23665. RI Bassom, Andrew/F-6691-2014; Stephen, Sharon/B-1011-2016 OI Stephen, Sharon/0000-0001-8204-8419 NR 20 TC 4 Z9 4 U1 0 U2 0 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0272-4960 J9 IMA J APPL MATH JI IMA J. Appl. Math. PY 1991 VL 46 IS 3 BP 269 EP 296 DI 10.1093/imamat/46.3.269 PG 28 WC Mathematics, Applied SC Mathematics GA FT554 UT WOS:A1991FT55400006 ER PT J AU KOSTIUK, T DEMING, D AF KOSTIUK, T DEMING, D TI A SOLAR INFRARED PHOTOMETER FOR SPACE-FLIGHT APPLICATION SO INFRARED PHYSICS LA English DT Article ID TOTAL IRRADIANCE; OSCILLATIONS; CHROMOSPHERE AB Solar radiation at wavelengths longward of 1.6-mu-m can be used to great advantage as a probe of the thermal state of the solar photospher. We describe a photometer concept which is capable of nearly simultaneous measurements of solar radiation from 1.6 to 200-mu-m in seven wavelength bands. This range of wavelengths can probe the solar photosphere from below the level of unit optical depth in the visible to the temperature minimum, approximately 500 km above it. An instrument package including a 20-cm Gregorian telescope and a filter wheel photometer utilizing non-cryogenic pyroelectric infared detectors is described. Approaches to the rejection of the visible solar spectrum in the instrument, the availability of optical and mechanical components, and the expected instrumental sensitivity are discussed. For wavelengths below 35-mu-m the projectes instrumental senstivity are discussed. detect the intensity signature of solar p-mode oscillations in a single 5 minutes of integration. For longer wavelengths clear detection is expected using Fourier analysis of modest data sets. The size, mass and power requirements of the photometer are well within constraints imposed by space missions, including those by the NASA Small Explorer program. RP KOSTIUK, T (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,PLANETARY SYST BRANCH,CODE 693,GREENBELT,MD 20771, USA. RI Kostiuk, Theodor/A-3077-2014 NR 20 TC 5 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-0891 J9 INFRARED PHYS PY 1991 VL 32 BP 225 EP 233 DI 10.1016/0020-0891(91)90112-S PG 9 WC Optics; Physics, Applied SC Optics; Physics GA FB121 UT WOS:A1991FB12100024 ER PT J AU ANDERSON, MS AF ANDERSON, MS TI THE MIDINFRARED BICONICAL REFLECTANCE OF THIN-FILMS ON HIGHLY ORIENTED PYROLYTIC-GRAPHITE SO INFRARED PHYSICS LA English DT Note ID SCANNING TUNNELING MICROSCOPY AB The biconical reflectance of highly oriented pyrolytic graphite in the MIR spectral region between 4000 and 600 cm-1 has been measured. The use of this material as a substrate for reflection-absorption measurements aiding in scanning tunneling microscopy of protein films is presented. RP ANDERSON, MS (reprint author), CALTECH,JET PROP LAB,SPACE MAT SCI & TECHNOL SECT,PASADENA,CA 91109, USA. NR 7 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-0891 J9 INFRARED PHYS PY 1991 VL 31 IS 5 BP 539 EP 540 DI 10.1016/0020-0891(91)90034-D PG 2 WC Optics; Physics, Applied SC Optics; Physics GA GF234 UT WOS:A1991GF23400020 ER PT J AU PIROUZ, P YANG, JW POWELL, JA ERNST, F AF PIROUZ, P YANG, JW POWELL, JA ERNST, F TI THE ROLE OF DISLOCATIONS IN THE 3C -LESS-THAN-GREATER-THAN-6H SIC POLYTYPIC TRANSFORMATION SO INSTITUTE OF PHYSICS CONFERENCE SERIES LA English DT Article ID COMPOUND SEMICONDUCTORS AB Experimental evidence is presented for a dislocation mechanism of polytypic transformation in SiC. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. MAX PLANCK INST MET RES,W-7000 STUTTGART 80,GERMANY. RP PIROUZ, P (reprint author), CASE WESTERN RESERVE UNIV,DEPT MAT SCI & ENGN,CLEVELAND,OH 44106, USA. RI Ernst, Frank/J-4016-2013 NR 11 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0951-3248 J9 INST PHYS CONF SER JI Inst. Phys. Conf. Ser. PY 1991 IS 117 BP 149 EP 154 PG 6 WC Physics, Multidisciplinary SC Physics GA HJ307 UT WOS:A1991HJ30700029 ER PT J AU KRISHNAKUMAR, E SRIVASTAVA, SK IGA, I AF KRISHNAKUMAR, E SRIVASTAVA, SK IGA, I TI DISSOCIATIVE ATTACHMENT OF ELECTRONS WITH SI2H6 SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article ID NEGATIVE-IONS; IONIZATION; SILICON; SILANE; IMPACT; HEATS; SIH2; CO AB Cross-sections for the production of negative ion fragments by electron attachment to Si2H6 and ion pair formation from it have been measured by utilizing the crossed electron beam-molecular beam collision technique. The negative ions are mass analyzed by employing a quadrupole mass spectrometer. There are serious disagreements between the present and two previously published results. In the present paper cross-section values, appearance potentials, and the various channels of dissociation for the formation of negative monosilane fragments are presented. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV FED SAO CARLOS,DEPT QUIM,BR-13560 SAO CARLOS,SP,BRAZIL. RI Iga, Ione/C-1273-2015 NR 16 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD JAN 1 PY 1991 VL 103 IS 2-3 BP 107 EP 115 DI 10.1016/0168-1176(91)80082-X PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA EW357 UT WOS:A1991EW35700004 ER PT J AU Christoforou, AP Swanson, SR AF Christoforou, A. P. Swanson, S. R. TI ANALYSIS OF IMPACT RESPONSE IN COMPOSITE PLATES SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article AB The problem of impact is of considerable interest in laminated composite materials. Although important contributions have been made in understanding the impact problem through numerical solutions. an analytical solution has not been available for the problem of impact of laminated plates. The present work gives an analytical solution to this problem, basal on the usual Fourier series expansion for simply-supported plates, combined with Laplace transform techniques for the impact problem solution. C1 [Christoforou, A. P.; Swanson, S. R.] Univ Utah, Dept Mech Engn, Salt Lake City, UT 84112 USA. RP Christoforou, AP (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 14 TC 49 Z9 52 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PY 1991 VL 27 IS 2 BP 161 EP 170 DI 10.1016/0020-7683(91)90226-6 PG 10 WC Mechanics SC Mechanics GA V00EJ UT WOS:000206771300003 ER PT J AU NOOR, AK BURTON, WS PETERS, JM AF NOOR, AK BURTON, WS PETERS, JM TI ASSESSMENT OF COMPUTATIONAL MODELS FOR MULTILAYERED COMPOSITE CYLINDERS SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article ID SHEAR-DEFORMATION-THEORY; SHELL-TYPE PANELS; CYLINDRICAL-SHELLS; RESPONSE ANALYSIS; VIBRATION; LOAD AB A study is made of the effects of variation in the lamination and geometric parameters of multilayered composite cylinders on the accuracy of the static and vibrational responses predicted by eight modeling approaches, based on two-dimensional shear-deformation shell theories. The standard of comparison is taken to be the exact three-dimensional elasticity solutions, and the quantities compared include both the gross response characteristics (e.g. vibration frequencies, strain energy components, average through-the-thickness displacements and rotations); and detailed, through-the-thickness, distributions of displacements, stresses and strain energy densities. Based on the numerical studies conducted, a predictor-corrector approach, used in conjunction with the first-order shear-deformation theory (with five displacement parameters in the predictor phase), appears to be the most effective among the eight modeling approaches considered. For multilayered orthotropic cylinders the response quantities obtained by the predictor-corrector approach are shown to be in close agreement with the exact three-dimensional elasticity solutions for a wide range of lamination and geometric parameters. The potential of this approach for predicting the response of multilayered shells with complicated geometry is also discussed. RP NOOR, AK (reprint author), UNIV VIRGINIA,NASA LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 50 TC 52 Z9 54 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PY 1991 VL 27 IS 10 BP 1269 EP 1286 DI 10.1016/0020-7683(91)90162-9 PG 18 WC Mechanics SC Mechanics GA EV625 UT WOS:A1991EV62500003 ER PT J AU CANTRELL, JH SALAMA, K AF CANTRELL, JH SALAMA, K TI ACOUSTOELASTIC CHARACTERIZATION OF MATERIALS SO INTERNATIONAL MATERIALS REVIEWS LA English DT Review ID ACOUSTIC-RADIATION STRESS; ORDER ELASTIC-CONSTANTS; NONLINEARITY PARAMETERS; TEMPERATURE-DEPENDENCE; RESIDUAL-STRESSES; SOLIDS; MICROSCOPY AB The increasing demand for new, more reliable materials, which are often used in hostile environments, has led to the necessity of establishing equally reliable, quantitative techniques for the non-destructive evaluation (NDE) and characterisation of such materials. Non-destructive evaluation methods are commonly used in applications ranging from materials processing and control to monitoring the effects of environmental degradation and the estimation of remaining useful life of materials. Although linear ultrasonic methods have long been among the most popular and useful of NDE methodologies, this review is concerned with the considerable effort that has been expended recently on understanding, developing, and applying non-linear acoustoelastic techniques. Although applications to complex materials are usually correlative, recent progress in the quantitative modelling of the acoustoelastic properties of multiphase alloys in terms of material composition is also reviewed. Considerable emphasis is placed on understanding the relationship between non-linear acoustoelastic properties and the fundamental atomic structure of simple materials. Such considerations lead to an enhanced understanding of the effect of residual and applied stresses on the acoustoelastic and thermoelastic measurements of metallic alloys. Similar considerations of magnetic domain structure provide an explanation of the effect of stress on the magnetoelastic properties of ferromagnetic materials. Implications of these advances to the non-destructive characterisation and evaluation of materials are discussed. C1 UNIV HOUSTON,DEPT MECH ENGN,HOUSTON,TX 77004. RP CANTRELL, JH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 74 TC 38 Z9 39 U1 5 U2 16 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 0950-6608 J9 INT MATER REV JI Int. Mater. Rev. PY 1991 VL 36 IS 4 BP 125 EP 145 PG 21 WC Materials Science, Multidisciplinary SC Materials Science GA GJ381 UT WOS:A1991GJ38100001 ER PT B AU JONES, FC AF JONES, FC BE BLOEMEN, H TI STATIC VERSUS DYNAMIC COSMIC-RAY HALOS SO INTERSTELLAR DISK-HALO CONNECTION IN GALAXIES SE IAU SYMPOSIA LA English DT Proceedings Paper CT 144TH SYMP OF THE INTERNATIONAL ASTRONOMICAL UNION ON THE INTERSTELLAR DISK-HALO CONNECTION IN GALAXIES CY JUN 18-22, 1990 CL LEIDEN, NETHERLANDS SP INT ASTRON UNION, KLUWER ACAD PUBL, LAB SPACE RES LEIDEN, LEIDEN UNIV, LEIDEN OBSERV, LEIDEN KERKHOVEN BOSSCHA FONDS, PHILIPS, ROYAL DUTCH ACAD ARTS & SCI ID GALAXY RP JONES, FC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA DORDRECHT BN 0-7923-1255-4 J9 IAU SYMP PY 1991 VL 144 BP 359 EP 368 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BV33P UT WOS:A1991BV33P00047 ER PT J AU NOEBE, RD MISRA, A GIBALA, R AF NOEBE, RD MISRA, A GIBALA, R TI PLASTIC-FLOW AND FRACTURE OF B2 NIAL-BASED INTERMETALLIC ALLOYS CONTAINING A DUCTILE 2ND PHASE SO ISIJ INTERNATIONAL LA English DT Review DE NIAL; NIAL-BASED COMPOSITES; B2-TYPE INTERMETALLIC ALLOYS; DUCTILE PHASE TOUGHENING; FRACTURE TOUGHNESS; TENSILE DUCTILITY ID ROOM-TEMPERATURE DUCTILITY; 1050 DEGREES K; SINGLE-CRYSTALS; AL ALLOYS; MARTENSITIC-TRANSFORMATION; MECHANICAL-PROPERTIES; UNIFORM DEFORMATION; MATRIX COMPOSITES; BRITTLE MATERIALS; FE-AL AB The use of NiAl as a structural material has been hindered by its lack of tensile ductility or toughness at room temperature. The operative flow and fracture mechanisms in monolithic NiAl leading to these poor low temperature properties are analyzed, demonstrating the need for ductile phase toughening. Progress in ductile phase reinforced intermetallics and NiAl-based materials are reviewed and the primary mechanisms involved in the flow and fracture of ductile phase reinforced alloys are clarified by recent investigations of directionally solidified NiAl-based materials. The mechanical behavior of these model alloys (Ni-30Al and Ni-30Fe-20Al (at%)) are discussed. The prospects for developing a ductile phase toughened NiAl-based alloy and the shortcomings presently inherent in these systems are analyzed. C1 UNIV MICHIGAN,DEPT MAT SCI & ENGN,ANN ARBOR,MI 48109. RP NOEBE, RD (reprint author), NASA,LEWIS RES CTR,MS 49-3,CLEVELAND,OH 44135, USA. RI Misra, Amit/H-1087-2012 NR 139 TC 65 Z9 68 U1 0 U2 6 PU IRON STEEL INST JAPAN KEIDANREN KAIKAN PI TOKYO PA 9-4 OTEMACHI 1-CHOME CHIYODA-KU, TOKYO 100, JAPAN SN 0915-1559 J9 ISIJ INT JI ISIJ Int. PY 1991 VL 31 IS 10 BP 1172 EP 1185 DI 10.2355/isijinternational.31.1172 PG 14 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA GK104 UT WOS:A1991GK10400019 ER PT J AU PROGAR, DJ STCLAIR, TL AF PROGAR, DJ STCLAIR, TL TI ADHESIVE EVALUATION OF BISIMIDE ADDITIVES IN LARC-TPI SO JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY LA English DT Article DE POLYIMIDES; ADHESIVE; BISIMIDE; LAP SHEAR STRENGTH AB Studies at NASA Langley Research Center had shown that the processability of aromatic polyimides can be improved by the addition of bis(amide acids) or bisimides to LARC-TPI. These low-molecular-weight additives apparently lower the melt viscosity of aromatic polyimides without affecting their glass transition temperatures. Well-consolidated, fiber-reinforced composites have been fabricated using this technology. LARC-TPI can be processed as a thermoplastic polyimide to form high strength bonds. However, this is generally accomplished by processing at relatively high bonding pressures, i.e. 2.07 MPa (300 psi). This paper covers the investigation of the effects of two bisimide additives to LARC-TPI adhesive in an attempt to improve the bonding process by lowering the viscosity of the material to achieve improved bond strength properties at lower bonding pressures. The results indicate some improvement in room temperature lap shear strength for the doped adhesives for the lowest bonding pressure, 0.34 MPa (50 psi), but some decrease in elevated temperature strength (232-degrees-C) for the phthalic anhydride-p-phenylenediamine-phthalic anhydride (C-PDA) system. The aniline-pyromellitic dianhydride-aniline (C-PMDA) system, bonded at 2.07 MPa (300 psi), exhibited comparable strengths to LARC-TPI after thermal and water boil exposures. The high flow exhibited by the additive in the melt state was not effective in lowering the viscosity of the more viscous LARC-TPI at the additive levels investigated. RP PROGAR, DJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 13 TC 11 Z9 11 U1 0 U2 1 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-4243 J9 J ADHES SCI TECHNOL JI J. Adhes. Sci. Technol. PY 1991 VL 5 IS 9 BP 711 EP 726 DI 10.1163/156856191X00657 PG 16 WC Engineering, Chemical; Materials Science, Multidisciplinary; Mechanics SC Engineering; Materials Science; Mechanics GA GH722 UT WOS:A1991GH72200003 ER PT J AU ADELMAN, HM MANTAY, WR AF ADELMAN, HM MANTAY, WR TI INTEGRATED MULTIDISCIPLINARY DESIGN OPTIMIZATION OF ROTORCRAFT SO JOURNAL OF AIRCRAFT LA English DT Article AB This paper describes a joint NASA/Army research activity at the NASA Langley Research Center to develop optimization procedures aimed at improving the rotor blade design process by integrating appropriate disciplines and accounting for important interactions among the disciplines. The activity is being guided by a steering committee made up of key NASA and Army researchers and managers. The committee, which has been named IRASC (Integrated Rotorcraft Analysis Steering Committee), has defined two principal foci for the activity: a "white paper," which sets forth the goals and plans for the effort; and a rotor design project, which will validate the basic constituents as well as the overall design methodology for multidisciplinary optimization. The paper describes the optimization formulation in terms of the objective function, design variables, and constraints. The analysis aspects are discussed, and an initial attempt at defining the interdisciplinary coupling is summarized. At this writing, some significant progress has been made. Results are given in the paper that represent accomplishments in rotor aerodynamic performance optimization for minimum hover horsepower, rotor dynamic optimization for vibration reduction, rotor structural optimization for minimum weight, and integrated aerodynamic load/dynamics optimization for minimum vibration and weight. RP ADELMAN, HM (reprint author), NASA,LANGLEY RES CTR,INTERDISCIPLINARY RES OFF,HAMPTON,VA 23665, USA. NR 0 TC 13 Z9 15 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN PY 1991 VL 28 IS 1 BP 22 EP 28 DI 10.2514/3.45988 PG 7 WC Engineering, Aerospace SC Engineering GA FH227 UT WOS:A1991FH22700002 ER PT J AU NISSIM, E AF NISSIM, E TI REDUCTION OF AERODYNAMIC AUGMENTED STATES IN ACTIVE FLUTTER SUPPRESSION SYSTEMS SO JOURNAL OF AIRCRAFT LA English DT Article AB A method is proposed by which an aeroservoelastic problem is brought to a state-space form with a minimum number of augmented aerodynamic terms. The examples treated in this work relate to NASA's Drone for Aerodynamic and Structural Testing, Aerodynamic Research Wing 1, and to the YF-17 fighter model. It is shown that, in all cases considered, the method yields a very good accuracy regarding the flutter parameters and the dynamic behavior of the systems, using only two augmented aerodynamic states. The method should prove useful in the design of lower order control laws based on optimal control theory. RP NISSIM, E (reprint author), NASA,AMES RES CTR,DRYDEN FLIGHT RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 4 Z9 5 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN PY 1991 VL 28 IS 1 BP 82 EP 93 DI 10.2514/3.45995 PG 12 WC Engineering, Aerospace SC Engineering GA FH227 UT WOS:A1991FH22700009 ER PT J AU LEE, EM BATINA, JT AF LEE, EM BATINA, JT TI CONICAL EULER SIMULATION OF WING ROCK FOR A DELTA-WING PLANFORM SO JOURNAL OF AIRCRAFT LA English DT Note RP LEE, EM (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,UNSTEADY AERODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 0 TC 3 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD JAN PY 1991 VL 28 IS 1 BP 94 EP 96 DI 10.2514/3.45996 PG 3 WC Engineering, Aerospace SC Engineering GA FH227 UT WOS:A1991FH22700010 ER PT J AU FULTON, R HEYMSFIELD, GM AF FULTON, R HEYMSFIELD, GM TI MICROPHYSICAL AND RADIATIVE CHARACTERISTICS OF CONVECTIVE CLOUDS DURING COHMEX SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DUAL-POLARIZATION RADAR; MULTIPLE MICROWAVE-FREQUENCIES; MULTIPARAMETER RADAR; PRECIPITATING CLOUD; RAIN RATES; 183 GHZ; HAIL; WAVELENGTH; SPACE; SATELLITE AB The use of passive remote microwave radiance measurements above cloud tops for rainrate estimation is complicated by the complex nature of cloud microphysics. The knowledge of the microphysical structure of clouds, specifically the hydrometeor types, shapes, sizes, and their vertical distribution, is important because radiative emission and scattering effects are dependent upon the hydrometeor distribution. This paper has two purposes: first, to document the structure and evolution of two strong thunderstorms in Alabama using radar multiparameter data; and second, to relate the inferred microphysics to the resulting upwelling microwave radiance observed concurrently by high altitude aircraft. These measurements were collected during the COHMEX field program in the summer of 1986. The radar analysis includes a description of the parameters reflectivity Z, differential reflectivity Z(DR), linear depolarization ratio LDR, and hail signal HS for two thunderstorm cases on 11 July 1986. The simultaneous aircraft data includes passive microwave brightness temperature (T(B)) measurements at four frequencies ranging from 18 to 183 GHz as well as visible and infrared data. The remote radar observations reveal the existence of large ice particles within the storms, which is likely to have caused the observed low microwave brightness temperatures. By relating the evolution of the radar measureables to the microwave T(B)'s it has been found that knowledge of the storm microphysics and its evolution is important to adequately understand the microwave T(B)'s. C1 GEN SCI CORP,LAUREL,MD. RP FULTON, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 973,GREENBELT,MD 20771, USA. NR 53 TC 30 Z9 31 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JAN PY 1991 VL 30 IS 1 BP 98 EP 116 DI 10.1175/1520-0450(1991)030<0098:MARCOC>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EZ146 UT WOS:A1991EZ14600006 ER PT J AU VINING, CB AF VINING, CB TI A MODEL FOR THE HIGH-TEMPERATURE TRANSPORT-PROPERTIES OF HEAVILY DOPED N-TYPE SILICON-GERMANIUM ALLOYS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LATTICE THERMAL-CONDUCTIVITY; MANY-VALLEY SEMICONDUCTORS; LIQUID-PHASE EPITAXY; THERMOELECTRIC ALLOYS; PHONON ATTENUATION; ELECTRON-MOBILITY; SIXGE1-X ALLOYS; DOPANT DENSITY; SCATTERING; PHOSPHORUS AB A model is presented for the high-temperature transport properties of large-grain-size, heavily doped n-type silicon-germanium alloys. Electron and phonon transport coefficients are calculated using standard Boltzmann equation expressions in the relaxation time approximation. Good agreement with experiment is found by considering acoustic phonon and ionized impurity scattering for electrons, and phonon-phonon, point defect, and electron-phonon scattering for phonons. The parameters describing electron transport in heavily doped and lightly doped materials are significantly different and suggest that most carriers in heavily doped materials are in a band formed largely from impurity states. The maximum dimensionless thermoelectric figure of merit for single-crystal, n-type Si0.8Ge0.2 at 1300 K is estimated at ZT congruent-to 1.13 with an optimum carrier concentration of n congruent-to 2.9 x 10(20) cm-3. RP VINING, CB (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 60 TC 175 Z9 175 U1 4 U2 55 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 1 PY 1991 VL 69 IS 1 BP 331 EP 341 DI 10.1063/1.347717 PG 11 WC Physics, Applied SC Physics GA ER430 UT WOS:A1991ER43000054 ER PT J AU PEREIRA, JM MANSOUR, JM DAVIS, BR AF PEREIRA, JM MANSOUR, JM DAVIS, BR TI DYNAMIC MEASUREMENT OF THE VISCOELASTIC PROPERTIES OF SKIN SO JOURNAL OF BIOMECHANICS LA English DT Note ID MECHANICAL-PROPERTIES; AGE AB A wave propagation technique was used to measure the dynamic viscoelastic properties of excised skin when subjected to a low incremental strain. The propagation velocity, attenuation, and storage and loss moduli were determined from measured characteristics of a pulse propagating along a strip of skin. Experiments were conducted with the skin subjected to static stresses of 1500 Pa and 20,000 Pa. At low static stresses the skin response was viscoelastic with a loss tangent of approximately 0.6. In the frequency range of 0-1000 Hz, the wave velocity was relatively constant while the attenuation increased roughly linearly with frequency. However, results depended on the static stress. At the higher stress level the velocity was greater and the attenuation less than at the lower stress. At low stresses both the storage and loss moduli were relatively constant over the frequency range tested. The strong viscoelastic behavior of the tissue at higher frequencies is not predicted from models of the tissue determined from quasi-static test methods. In selecting a model to describe the behavior of skin, the test methods used for establishing the model must be consistent with its intended application. C1 CASE WESTERN RESERVE UNIV,METROHLTH MED CTR,SCH MED,DEPT DERMATOL,CLEVELAND,OH 44109. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP PEREIRA, JM (reprint author), CASE WESTERN RESERVE UNIV,DEPT MECH & AEROSP ENGN,CLEVELAND,OH 44106, USA. FU NIA NIH HHS [1-P01-AG02921] NR 23 TC 46 Z9 48 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0021-9290 J9 J BIOMECH JI J. Biomech. PY 1991 VL 24 IS 2 BP 157 EP 162 DI 10.1016/0021-9290(91)90360-Y PG 6 WC Biophysics; Engineering, Biomedical SC Biophysics; Engineering GA FC475 UT WOS:A1991FC47500007 PM 2037615 ER PT J AU WHITSON, PA HULS, MH SAMS, CF AF WHITSON, PA HULS, MH SAMS, CF TI CHARACTERIZATION OF ATRIAL-NATRIURETIC-PEPTIDE RECEPTORS IN BRAIN MICROVESSEL ENDOTHELIAL-CELLS SO JOURNAL OF CELLULAR PHYSIOLOGY LA English DT Article ID CYCLIC-GMP ACCUMULATION; AORTIC SMOOTH-MUSCLE; GUANYLATE-CYCLASE; BINDING-SITES; BARRIER; MEMBRANE; CULTURE; ANALOGS; PROTEIN; PURIFICATION AB Atrial natriuretic peptide (ANP) binding and ANP-induced increases in cyclic guanosine monophosphate (cGMP) levels have been observed in brain microvessels (Chabrier et al., 1987; Steardo and Nathanson, 1987), suggesting that this fluid-regulating hormone may play a role in the fluid homeostasis of the brain. This study was initiated to characterize the ANP receptors in primary cultures of brain microvessel endothelial cells (BMECs). The apparent equilibrium dissociation constant, K(d), for ANP increased from 0.25 nM to 2.5 nM, and the number of ANP binding sites as determined by Scatchard analysis increased from 7,100 to 170,000 sites/cell between 2 and 10 days of culture following monolayer formation. Time- and concentration-dependent studies on the stimulation of cGMP levels by ANP indicated that guanylate cyclase-linked ANP receptors were present in BMECs. The relative abilities of ANP, brain natriuretic peptide (BNP), and a truncated analog of ANP containing amino acids 5-27 (ANP 5-27) to modulate the accumulation of cGMP was found to be ANP > BNP >> ANP 5-27. Affinity cross-linking with disuccinimidyl suberate and radiolabeled ANP followed by gel electrophoresis under reducing conditions demonstrated a single band corresponding to the 60-70 kD receptor, indicating the presence of the nonguanylate cyclase-linked ANP receptor. Radiolabeled ANP binding was examined in the presence of various concentrations of either ANP, BNP, or ANP 5-27 and suggested that a large proportion of the ANP receptors present in blood-brain barrier endothelial cells bind all of these ligands similarly. These data indicate both guanylate cyclase linked and nonguanylate cyclase linked receptors are present on BMECs and that a higher proportion of the nonguanylate cyclase linked receptors is expressed. This in vitro culture system may provide a valuable tool for the examination of ANP receptor expression and function in blood-brain barrier endothelial cells. C1 KRUG LIFE SCI,HOUSTON,TX 77058. RP WHITSON, PA (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058, USA. NR 46 TC 17 Z9 17 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-9541 J9 J CELL PHYSIOL JI J. Cell. Physiol. PD JAN PY 1991 VL 146 IS 1 BP 43 EP 51 DI 10.1002/jcp.1041460107 PG 9 WC Cell Biology; Physiology SC Cell Biology; Physiology GA EU576 UT WOS:A1991EU57600006 PM 1846636 ER PT J AU SUD, YC WALKER, GK SMITH, WE AF SUD, YC WALKER, GK SMITH, WE TI ANALYSIS OF A GENERAL-CIRCULATION MODEL SIMULATION OF THE ATMOSPHERIC RESPONSE TO THE OBSERVED SEA-SURFACE TEMPERATURE ANOMALIES OF JANUARY AND FEBRUARY 1983 SO JOURNAL OF CLIMATE LA English DT Note AB An ensemble of three sets of simulations is produced with the GLA (Goddard Laboratory for Atmospheres) GCM to assess the effect of the El Nino event of 1982-83 on winter climate. The three sets of runs are started from the analyzed initial states of the atmosphere for the 14, 15, and 16 December 1982, respectively, and are integrated through the end of February 1983. Each set consists of a control run, which was forced with climatological SSTs, and a corresponding anomaly run, which was forced with the observed SSTs. The ensemble mean of the model-simulated atmospheric circulation and rainfall anomalies is compared with the corresponding analyses of observations. Most of the observed circulation anomaly features in the tropics are simulated rather well by the model. The tropical sea level pressure anomalies show a typical ENSO pattern: 850 mb wind anomalies show westerly winds over the equatorial Pacific Ocean; 200 mb anomalous winds show anticyclonic vortices straddling the equator; and the 200 mb height anomalies agree well with the corresponding observations. The regions of statistically significant anomaly patterns in the tropics are also in good agreement with observations. The model simulated rainfall anomalies also compare well with the rainfall analysis based on satellite-derived water vapor in the atmosphere from 37 GHz SMMR data. The model's OLR anomaly patterns show close correspondence with the anomalies in satellite observations of OLR. However, there is about a 5-10 degree eastward shift in the major simulated anomalies. This shift is also evident directly over the warm water of the equatorial eastern Pacific, with an even larger shift in the associated patterns in the extratropics. This discrepancy in the simulations leads to some very poor anomaly correlations in the extratropics. RP SUD, YC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 911,GREENBELT,MD 20771, USA. NR 0 TC 6 Z9 6 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JAN PY 1991 VL 4 IS 1 BP 107 EP 115 DI 10.1175/1520-0442(1991)004<0107:AOAGCM>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EY797 UT WOS:A1991EY79700007 ER PT J AU KLEIN, JD FREEMAN, A AF KLEIN, JD FREEMAN, A TI QUADPOLARIZATION SAR CALIBRATION USING TARGET RECIPROCITY SO JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS LA English DT Article AB In this paper we present a novel algorithm for radiometric and polarimetric calibration of complex quadpolarization SAR data. It is based partially upon known targets in the image and partially upon the assumption of reciprocity of all other scatterers; no other assumptions about background scatterer statistics are required. The only manmade targets required by the basic algorithm are a trihedral-dihedral corner reflector pair for calibration at each range (a more general technique which requires two arbitrary passive targets is outlined as well). The algorithm presented here is an improvement over previous ones in that it does not require three known targets or azimuthal symmetry of the background to solve the polarimetric calibration problem. Results are presented using airborne SAR data. RP KLEIN, JD (reprint author), CALTECH,JET PROP LAB,RADAR SCI & SYST STUDIES GRP,MS 300-235,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 24 Z9 24 U1 0 U2 0 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0920-5071 J9 J ELECTROMAGNET WAVE JI J. Electromagn. Waves Appl. PY 1991 VL 5 IS 7 BP 735 EP 751 PG 17 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA FX831 UT WOS:A1991FX83100005 ER PT J AU HENDERSON, WP AF HENDERSON, WP TI AIRFRAME PROPULSION INTEGRATION AT TRANSONIC SPEEDS SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 35TH INTERNATIONAL GAS TURBINE AND AEROENGINE CONGRESS AND EXPOSITION CY JUN 11-14, 1990 CL BRUSSELS, BELGIUM AB A significant level of research is ongoing at NASA's Langley Research center on integrating the propulsion system with the aircraft. This program has included nacelle/pylon/wing integration for turbofan transports, propeller/nacelle/wing integration for turboprop transports, and nozzle/afterbody/empennage integration for high-performance aircraft. The studies included in this paper focus more specifically on pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelle and wing contouring, and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high-performance aircraft. The studies were primarily conducted in NASA Langley's 16-Foot Transonic Tunnel at Mach numbers up to 1.20. RP HENDERSON, WP (reprint author), NASA,LANGLEY RES CTR,CTR APPL AERODYNAM,HAMPTON,VA 23665, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JAN PY 1991 VL 113 IS 1 BP 51 EP 59 DI 10.1115/1.2906530 PG 9 WC Engineering, Mechanical SC Engineering GA FE820 UT WOS:A1991FE82000007 ER PT J AU AMUEDO, KC WILLIAMS, BR FLOOD, JD JOHNS, AL AF AMUEDO, KC WILLIAMS, BR FLOOD, JD JOHNS, AL TI STOVL HOT GAS INGESTION CONTROL TECHNOLOGY SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article AB A comprehensive wind tunnel test program was conducted to evaluate control of Hot Gas Ingestion (HGI) on a 9.2 percent scale model of the McDonnell Aircraft Company model 279-3C advanced Short Takeoff and Vertical Landing (STOVL) configuration. The test was conducted in the NASA-Lewis Research Center 9 ft by 15 ft Low Speed Wind Tunnel during the summer of 1987. Initial tests defined baseline HGI levels as determined by engine face temperature rise and temperature distortion. Subsequent testing was conducted to evaluate HGI control parametrically using Lift Improvement Devices (LIDs), forward nozzle splay angle, a combination of LIDs and forward nozzle splay angle, and main inlet blocking. The results from this test program demonstrate that HGI can be effectively controlled and that HGI is not a barrier to STOVL aircraft development. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP AMUEDO, KC (reprint author), MCDONNELL AIRCRAFT CORP,MCDONNELL DOUGLAS CORP,ST LOUIS,MO 63161, USA. NR 2 TC 0 Z9 0 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JAN PY 1991 VL 113 IS 1 BP 68 EP 74 DI 10.1115/1.2906532 PG 7 WC Engineering, Mechanical SC Engineering GA FE820 UT WOS:A1991FE82000009 ER PT J AU SMITH, RH CHISHOLM, JD STEWART, JF AF SMITH, RH CHISHOLM, JD STEWART, JF TI OPTIMIZING AIRCRAFT PERFORMANCE WITH ADAPTIVE, INTEGRATED FLIGHT PROPULSION CONTROL SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 35TH INTERNATIONAL GAS TURBINE AND AEROENGINE CONGRESS AND EXPOSITION CY JUN 11-14, 1990 CL BRUSSELS, BELGIUM AB An adaptive, integrated flight/propulsion control algorithm called Performance Seeking Control (PSC) has been developed to optimize total aircraft performance during steady-state engine operation. The multimode algorithm will minimize fuel consumption at cruise conditions; maximize excess thrust (thrust minus drag) during aircraft accelerations, climbs, and dashes; and extend engine life by reducing Fan Turbine Inlet Temperature (FTIT) when the extended life mode is engaged. On-board models of the inlet, engine, and nozzle are optimized to compute a set of control trims, which are then applied as increments to the nominal engine and inlet control schedules. The on-board engine model is continually updated to match the operating characteristics of the actual engine cycle through the use of a Kalman filter, which accounts for anomalous engine operation. The PSC algorithm will be flight demonstrated on an F-15 test aircraft under the direction of the NASA Ames/Dryden Flight Research Facility. This paper discusses the PSC design strategy, describes the control algorithm, and presents results from high-fidelity, nonlinear aircraft/engine simulations. Simulation results indicate that thrust increases as high as 15 percent and specific fuel consumption reductions up to 3 percent are realizable by the PSC system. C1 NASA,AMES,DRYDEN,EDWARDS AIR FORCE BASE,CA 93523. RP SMITH, RH (reprint author), MCDONNELL AIRCRAFT CORP,MCDONNELL DOUGLAS CORP,ST LOUIS,MO 63043, USA. NR 7 TC 2 Z9 5 U1 2 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JAN PY 1991 VL 113 IS 1 BP 87 EP 94 DI 10.1115/1.2906535 PG 8 WC Engineering, Mechanical SC Engineering GA FE820 UT WOS:A1991FE82000012 ER PT J AU OBENHUBER, DC LOWRANCE, R AF OBENHUBER, DC LOWRANCE, R TI REDUCTION OF NITRATE IN AQUIFER MICROCOSMS BY CARBON ADDITIONS SO JOURNAL OF ENVIRONMENTAL QUALITY LA English DT Article ID DENITRIFICATION; SOILS AB Aquifer microcosms were used to examine the effects of NO3- and C amendments on groundwater from the Claiborne aquifer. Nitrate concentrations of 12.17 mg L-1 in aquifer microsams were reduced 0.92%/d to 5.84 mg L-1 by the addition of 10 mg C L-1 for 35 d. Nitrate disappearance correlated with increases in number of dentrifiers and dissolved N2O concentration and decreases in dissolved oxygen, suggesting biological dentrification. Nitrate/chloride ratios decreased in microcosms with 10 mg C L-1 added and then increased when the C addition was removed. Carbon additions of 0.4 mg C L-1 had no effect on the microbial or chemical properties of the microcosms. Nitrous oxide levels in wells sampling the Claiborne aquifer showed an increase with depth, indicating N2O production within the aquifer. Microcosms are useful tools to examine biological transformations of chemical contaminants in unconsolidated aquifer material. The remediation of NO3- contaminated aquifer by organic infusion is possible and appears to be a function of microbial denitrification. C1 USDA ARS,SE WATERSHED RES LAB,TIFTON,GA 31793. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 22 TC 55 Z9 58 U1 0 U2 2 PU AMER SOC AGRONOMY PI MADISON PA 677 S SEGOE RD, MADISON, WI 53711 SN 0047-2425 J9 J ENVIRON QUAL JI J. Environ. Qual. PD JAN-MAR PY 1991 VL 20 IS 1 BP 255 EP 258 PG 4 WC Environmental Sciences SC Environmental Sciences & Ecology GA EY996 UT WOS:A1991EY99600041 ER PT J AU NOEVER, DA MATSOS, HC AF NOEVER, DA MATSOS, HC TI A BIOASSAY FOR MONITORING CADMIUM BASED ON BIOCONVECTIVE PATTERNS SO JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-ENVIRONMENTAL SCIENCE AND ENGINEERING & TOXIC AND HAZARDOUS SUBSTANCE CONTROL LA English DT Article DE CADMIUM; BIOASSAY; BIOCONVECTION; TETRAHYMENA-PYRIFORMIS ID NETWORKS AB The effects of cadmium, one of the most lethal bivalent heavy metals, tend to concentrate in protozoa far above natural levels and therein begin transferring through freshwater food chains to animals and humans. A simple assay using the toxic response of the protozoa, Tetrahymena pyriformis, is described. The assay relies on macroscopic bioconvective patterns to measure the toxic response, giving a sensitivity better than 1-mu-g/l and a toxicity threshold to 7-mu-g/l for Cd+2. Unlike previous efforts, this method does not require electronic or chemical analyses to monitor toxicity. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,BIOPHYS BRANCH,ES-76,HUNTSVILLE,AL 35812, USA. NR 13 TC 7 Z9 7 U1 0 U2 0 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 SN 1077-1204 J9 J ENVIRON SCI HEAL A JI J. Environ. Sci. Health Part A-Environ. Sci. Eng. Toxic Hazard. Subst. Control PY 1991 VL 26 IS 2 BP 273 EP 286 PG 14 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA FF210 UT WOS:A1991FF21000007 ER PT J AU NOEVER, DA MATSOS, HC AF NOEVER, DA MATSOS, HC TI CALCIUM PROTECTION FROM CADMIUM POISONING - BIOCONVECTIVE INDICATORS IN TETRAHYMENA SO JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-ENVIRONMENTAL SCIENCE AND ENGINEERING & TOXIC AND HAZARDOUS SUBSTANCE CONTROL LA English DT Article DE CADMIUM; BIOASSAY; BIOCONVECTION; TETRAHYMENA PYRIFORMIS ID PYRIFORMIS AB A bioassay using the motile response of the protozoa, Tetrahymena pyriformis, has been used to detect cadmium toxicity and subsequent in vivo protective effects of calcium. The assay relies on macroscopic bioconvective patterns to score the toxic response, with patterns showing a linear dose-response between 0-0.05 M Ca and greater protection for high calcium levels. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,BIOPHYS BRANCH,ES 76,HUNTSVILLE,AL 35812, USA. NR 6 TC 2 Z9 2 U1 1 U2 2 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 SN 1077-1204 J9 J ENVIRON SCI HEAL A JI J. Environ. Sci. Health Part A-Environ. Sci. Eng. Toxic Hazard. Subst. Control PY 1991 VL 26 IS 7 BP 1105 EP 1113 PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA GC843 UT WOS:A1991GC84300006 ER PT J AU MCTIGUE, TA ZIMMERMAN, RJ AF MCTIGUE, TA ZIMMERMAN, RJ TI CARNIVORY VS HERBIVORY IN JUVENILE PENAEUS-SETIFERUS (LINNAEUS) AND PENAEUS-AZTECUS (IVES) SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE CARNIVORY; HERBIVORY; MARSH; PENAEID ID TEXAS SALT-MARSH; BROWN SHRIMP; FOOD-WEBS; NORTH-CAROLINA; TIDAL FLATS; ESTUARY; ASSIMILATION; MERGUIENSIS; MORTALITY; DENSITIES AB Postlarval Penaeus setiferus (Linnaeus), the white shrimp, and Penaeus aztecus (Ives), the brown shrimp, were reared for 24 days on vegetal, animal, and combination diets. Incremental weight change was used to compare shrimp growth rates among dietary treatments. Both species grew most quickly when fed a combination diet. Shrimp fed an animal diet also grew, but those fed vegetal diets either did not survive or grew very little. There were significantly differences between the relative responses of the two species. Brown shrimp fed an animal diet of Artemia grew significantly more than did the white shrimp. Furthermore, the diatom Skeletonema was capable of producing growth in white shrimp that was similar to that produced by an Artemia diet until Day 20, but shrimp fed this vegetal diet did not survive until Day 24. There was no difference in the growth between white and brown shrimp fed a combination diet. The differences between the two species in their ability to utilize plant and animal material can be related to the resources available at their times of immigration. RP MCTIGUE, TA (reprint author), NOAA,NATL MARINE FISHERIES SERV,GALVESTON LAB,4700 AVE U,GALVESTON,TX 77550, USA. NR 60 TC 38 Z9 39 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PY 1991 VL 151 IS 1 BP 1 EP 16 DI 10.1016/0022-0981(91)90011-K PG 16 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA GG858 UT WOS:A1991GG85800001 ER PT J AU MALLETT, JC BEGHIAN, LE METCALF, TG KAYLOR, JD AF MALLETT, JC BEGHIAN, LE METCALF, TG KAYLOR, JD TI POTENTIAL OF IRRADIATION TECHNOLOGY FOR IMPROVED SHELLFISH SANITATION SO JOURNAL OF FOOD SAFETY LA English DT Article ID HEPATITIS-A-VIRUS; AEROMONAS-HYDROPHILA AB Ionizing radiation is shown capable of serving as an effective sanitizing treatment improving the sanitary quality of shellfish and providing an increased margin of safety for shellfish consumers. Co-60 irradiation of the hard-shelled clam, Mercenaria mercenaria, and the oyster, Crassostrea virginica, significantly reduced virus carriage numbers without unduly affecting shellfish survival rates or desirable organoleptic qualities. A D10 value of 2 kGy was determined for depletion of hepatitis A virus in clams and oysters as measured by in situ hybridization fluorescent foci and cytopathology enumeration methods. A D10 value of 2.4 kGy was determined for depletion of rotavirus SA11 in clams and oysters as measured by a plaque forming unit enumeration method. Study results showed ionizing radiation capable of providing an extra, highly effective safe-guard of shellfish sanitary quality when combined with traditional depuration treatment. Data drawn from other studies is introduced which shows D10 values as low as 1.0 kGy effectively eliminate Vibrio cholerae, and V. parahemolyticus, from shellfish. C1 BAYLOR COLL MED,DIV MOLEC VIROL,HOUSTON,TX 77030. NATL MARINE FISHERIES SERV,NE FISHERIES CTR,GLOUCESTER LAB,GLOUCESTER,MA 01930. RP MALLETT, JC (reprint author), UNIV LOWELL,DEPT BIOL SCI,RADIAT LAB,1 UNIV AVE,LOWELL,MA 01854, USA. NR 28 TC 29 Z9 31 U1 0 U2 5 PU FOOD NUTRITION PRESS INC PI TRUMBULL PA 6527 MAIN ST, P O BOX 374, TRUMBULL, CT 06611 SN 0149-6085 J9 J FOOD SAFETY JI J. Food Saf. PY 1991 VL 11 IS 4 BP 231 EP 245 DI 10.1111/j.1745-4565.1991.tb00055.x PG 15 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA GC657 UT WOS:A1991GC65700001 ER PT J AU MACHADO, ME MOORE, RL AF MACHADO, ME MOORE, RL TI MAGNETIC ENERGY-STORAGE AND CONVERSION IN TRANSIENT SOLAR-ACTIVITY - OBSERVATIONS SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL PHYSICS SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID FLARE; REGION; RELEASE; EVENTS; FLUX AB The driver of transient solar activity is magnetic free energy stored in non-potential configurations. This energy is released impulsively, within a period of the order of 10 to 1000 seconds, by an as yet not completely understood process or chain of processes. We review our current knowledge of the observed characteristics of energy buildup and release, and the limitations of our understanding. We conclude that the coordinated international research effort, FLARES 22, is necessary for an effective attack on this problem of great importance to astrophysics, space physics, and space exploration. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP MACHADO, ME (reprint author), UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899, USA. NR 41 TC 2 Z9 2 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 1 EP 9 PN 1 PG 9 WC Geosciences, Multidisciplinary SC Geology GA JW705 UT WOS:A1991JW70500002 ER PT J AU FAIRFIELD, DH AF FAIRFIELD, DH TI SOLAR-WIND CONTROL OF THE SIZE AND SHAPE OF THE MAGNETOSPHERE SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL PHYSICS SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID INTERPLANETARY MAGNETIC-FIELD; BOW SHOCK; MAGNETOPAUSE; MAGNETOTAIL; MOTION; SUBSTORMS AB The position of the earth's magnetopause is controlled by the kinetic pressure of the solar Wind and further influenced by the north-south component of the interplanetary magnetic field. On average the distance to the subsolar magnetopause is approximately 10 R(E), but this distance varies with the solar wind pressure during the 11 year sunspot cycle. Maximum solar wind pressure occurs during the declining phase of the cycle and compresses the average subsolar magnetopause inside 10 R(E) while minimum pressure occurs during solar maximum, allowing expansion of the magnetopause outward toward 11 R(E). The north-south component of the IMF moves the subsolar magnetopause inward or outward approximately .25 R(E) for each 1 nT unit of negative or positive field strength, with the magnetotail expanding or contracting to contain the flux transported into the tail. Other observations suggest that the distant tail (1) may be flattened into an elliptical cross section with major axis aligned with the YZ component of the IMF and (2) is probably twisted by the torque exerted by interplanetary field lines connected to the tail lobes. Recent evidence suggests that reorientations of the upstream foreshock may produce density enhancements of a few minutes duration that impinge on the magnetopause and compress the magnetosphere. RP FAIRFIELD, DH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 25 TC 16 Z9 16 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 117 EP 127 PN 1 PG 11 WC Geosciences, Multidisciplinary SC Geology GA JW705 UT WOS:A1991JW70500012 ER PT J AU VOORHIES, CV AF VOORHIES, CV TI COUPLING AN INVISCID CORE TO AN ELECTRICALLY INSULATING MANTLE SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article ID GEOMAGNETIC-FIELD; ROTATION; FLOW AB The torque exerted on the mantle is examined with emphasis on purely mechanical topographic or pressure core-mantle coupling. Pressure perturbations accompanying tangentially geostrophic, frozen-flux core flow acting on core-mantle boundary topography can exert an "enormous" torque on the mantle if thermal core-mantle interactions drive such flow. Conditions for growing or changing a dipole and correlating its fluctuations with those in the length of the day are analyzed. RP VOORHIES, CV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEOL & GEOMAGNET BRANCH,CODE 922,GREENBELT,MD 20771, USA. RI Voorhies, Coerte/D-4672-2012 NR 33 TC 17 Z9 20 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 302 JIYUGAOKA-KOMATSU BLDG 24-17 MIDORIGAOKA 2-CHOME, TOKYO TOKYO 152, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 IS 2 BP 131 EP 156 PG 26 WC Geosciences, Multidisciplinary SC Geology GA FE914 UT WOS:A1991FE91400004 ER PT J AU HORWITZ, JL MOORE, TE GILES, BL WILSON, GR HO, CW LIN, J SWINNEY, KR AF HORWITZ, JL MOORE, TE GILES, BL WILSON, GR HO, CW LIN, J SWINNEY, KR TI KINETIC FEATURES OF CORE PLASMAS IN THE MAGNETOSPHERE - A NEW GENERATION OF OBSERVATIONS AND SIMULATIONS SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL PHYSICS SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID POLAR WIND; MODEL; BEHAVIOR AB Recent measurements and simulations of core or low-energy plasma phenomena have elucidated features of particle distributions which transcend the somewhat limited physical insights available from simple bulk parameter (density, flow velocity, temperature, etc.) descriptions alone. Two of the exciting new observational areas include: (1) Core ion measurements which display a new type of distribution function, the ion ring distribution, which may be produced by coherent waves and/or ion-neutral relative convective drift; and (2) A statistical analysis of core ion distribution functions, in which a programmed pattern recognition technique is used to objectively characterize the vast quantity of ion pitch angle distributions observed by Dynamics Explorer-1 and sort them and their properties according to location and geomagnetic activity level. Important areas of advances in simulation of large-scale transport of core plasmas include: (1) A new, self-consistent time-dependent particle-in-cell simulation of polar plasma outflow; and (2) A kinetic simulation of the early-stage plasmasphere refilling process, in which injected particles from conjugate polar wind flows onto a evacuated closed flux tube are allowed to suffer effects of turbulent heating and pitch angle scattering. C1 NASA,MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35899. UNIV ALABAMA,CTR SPACE PLASMA & AERONOM RES,HUNTSVILLE,AL 35899. RP HORWITZ, JL (reprint author), UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 24 TC 0 Z9 0 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 275 EP 284 PN 1 PG 10 WC Geosciences, Multidisciplinary SC Geology GA JW705 UT WOS:A1991JW70500025 ER PT J AU MAYR, HG HARRIS, I HERRERO, FA PESNELL, WD AF MAYR, HG HARRIS, I HERRERO, FA PESNELL, WD TI TRANSFER-FUNCTION MODEL (TFM) AND GRAVITY-WAVES SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL PHYSICS SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID DISSIPATIVE MULTICONSTITUENT MEDIUM; EARTHS THERMOSPHERE; GLOBAL EXCITATION; UPPER-ATMOSPHERE; MAGNETIC STORM; CIRCULATION; DYNAMICS; TEMPERATURE; WINDS AB The time consuming numerical integration of the conservation equations is restricted to compute the transfer function (TF). This TF describes the dynamic properties of the medium divorced from the complexities in the temporal and horizontal variations of the excitation source. Given the TF, the atmospheric response to a chosen source configuration is then obtained speedily. The model can describe thermospheric waves as well as impulsive perturbations on the globe and has been used in the interpretation of ground based and satellite observations. Our discussion here is limited to describe the characteristics of gravity waves. C1 APPL RES CORP,LANDOVER,MD 20785. RP MAYR, HG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Pesnell, William/D-1062-2012 OI Pesnell, William/0000-0002-8306-2500 NR 35 TC 0 Z9 0 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 525 EP 536 PN 1 PG 12 WC Geosciences, Multidisciplinary SC Geology GA JW705 UT WOS:A1991JW70500040 ER PT J AU JACKMAN, CH AF JACKMAN, CH TI EFFECTS OF ENERGETIC PARTICLES ON MINOR CONSTITUENTS OF THE MIDDLE ATMOSPHERE SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID SOLAR PROTON EVENT; MESOSPHERIC OZONE DEPLETION; NITRIC-OXIDE; STRATOSPHERIC OZONE; ODD NITROGEN; JULY 13; PRECIPITATION; CHEMISTRY; TRANSPORT; CYCLE-21 AB Both energetic protons and electrons can produce odd nitrogen compounds, NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HNO4, ClONO2), through interactions with the background atmosphere. The long lifetime of the NO(y) family (up to several months in the middle atmosphere) as well as the NO(y) species' significant influence on stratospheric ozone abundance make the charged particle increases of NO(y) important. Galactic cosmic rays produce NO(y) in the lower stratosphere, solar protons produce. NO(y) in the middle and upper stratosphere as well as the mesosphere, and relativistic electrons produce NO(y) in the upper stratosphere and mesosphere, each affecting the NO(y) middle atmosphere budget directly. Production of NO(y) constituents by solar protons has been associated with an observed polar ozone depletion during and after the August 1972 solar proton event and a polar NO increase after the July 1982 solar proton event. Auroral electron and photoelectron production of NO(x) (N, NO, NO2) in the thermosphere and its subsequent transport downwards to the polar mesosphere and. upper stratosphere is an important component of the NO(y) budget in the middle atmosphere in the wintertime at high latitudes, e.g., the NO2 enhancements measured by the limb infrared monitor of the stratosphere (LIMS) in the polar lower mesosphere and upper stratosphere during the winter of 1978-79 are thought to be caused by downward transport of NO(x). RP JACKMAN, CH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 916,GREENBELT,MD 20771, USA. RI Jackman, Charles/D-4699-2012 NR 48 TC 11 Z9 11 U1 1 U2 3 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 637 EP 646 PN 2 PG 10 WC Geosciences, Multidisciplinary SC Geology GA JW706 UT WOS:A1991JW70600006 ER PT J AU ROOD, RB AF ROOD, RB TI 3-DIMENSIONAL CONSTITUENT TRANSPORT MODELS AND THE STUDY OF INTERANNUAL VARIABILITY SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID MIDDLE ATMOSPHERE; PLANETARY-WAVES; SOLAR; STRATOSPHERE; OZONE; CIRCULATION AB An approach to using three-dimensional (3D) models to simulate realistic ozone variability is described. The technique represents planetary and tropospheric cyclonic scales accurately. Therefore, it is possible to define the origins of the dynamical variability of ozone. Then smaller effects, such as solar variability, can be evaluated against this realistic dynamical background. RP ROOD, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 NR 25 TC 0 Z9 0 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 687 EP 693 PN 2 PG 7 WC Geosciences, Multidisciplinary SC Geology GA JW706 UT WOS:A1991JW70600010 ER PT J AU BALACHANDRAN, NK PLUMB, RA SUOZZO, R RIND, D AF BALACHANDRAN, NK PLUMB, RA SUOZZO, R RIND, D TI THE QBO AND STRATOSPHERIC WARMING - MODEL RESULTS SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article ID QUASI-BIENNIAL OSCILLATION; MIDDLE ATMOSPHERE MODEL; CIRCULATION; PROPAGATION; VARIABILITY; WAVES AB Detailed studies of a wave-2 stratospheric warming simulated by a general circulation model of the middle atmosphere are presented. The December-January warming is preceded by increases in both wave-1 and wave-2 amplitudes several days prior to the warming. The warming peaks with a maximum in wave-2 amplitude, wave propagation towards the pole as shown by E-P flux vectors and increased E-P flux convergence. Forcing the tropical winds to correspond to the QBO patterns significantly alter the warming event. The warming is strengthened during the easterly phase of the QBO and weakened during the westerly phase. For the upper stratospheric warming of this study, the important factor seems to be the presence of easterlies near the equator around 40 km altitude, but the mechanism by which the equatorial winds influence the stratospheric warming is not clear. C1 STX SYST CORP, NEW YORK, NY USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. MIT, CAMBRIDGE, MA 02139 USA. NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP COLUMBIA UNIV, NEW YORK, NY 10027 USA. NR 17 TC 5 Z9 5 U1 0 U2 2 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158-0083, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 741 EP 757 PN 2 PG 17 WC Geosciences, Multidisciplinary SC Geology GA JW706 UT WOS:A1991JW70600015 ER PT J AU KING, JH AF KING, JH TI LONG-TERM SOLAR-WIND VARIATIONS AND ASSOCIATED DATA SOURCES SO JOURNAL OF GEOMAGNETISM AND GEOELECTRICITY LA English DT Article; Proceedings Paper CT 7TH QUADRENNIAL SOLAR TERRESTRIAL SYMP / 27TH COSPAR MEETING CY JUL 25-30, 1990 CL THE HAGUE, NETHERLANDS SP COMM SPACE RES, INT ASSOC GEOMAGNETISM & AERON, INT ASSOC METEOROL & ATMOSPHER PHYS, INT ASTRON UNION, INT UNION RADIO SCI, INT UNION PURE & APPL PHYS ID INTERPLANETARY MAGNETIC-FIELD; GRADIENTS; CYCLE-21; PIONEER-11 AB Near-Earth and deep space sources of in situ solar wind magnetic field and plasma data are reviewed, as well as the public accessibility of such data. Then the 1963-1989 multi-source hourly resolution compilation of near-Earth field and plasma parameters (the "OMNItape") is discussed. Finally, the variations in selected solar wind parameters over 2.5 solar cycles are presented and discussed. Variabilities among solar cycles are stressed. North-south asymmetries in the apparent rotation rate of the source of the solar wind and divergence of the solar wind flow away from the heliospheric current sheet are highlighted. RP KING, JH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,GREENBELT,MD 20771, USA. NR 26 TC 13 Z9 13 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO 158, JAPAN SN 0022-1392 J9 J GEOMAGN GEOELECTR JI J. Geomagn. Geoelectr. PY 1991 VL 43 SU S BP 865 EP 880 PN 2 PG 16 WC Geosciences, Multidisciplinary SC Geology GA JW706 UT WOS:A1991JW70600029 ER PT J AU WONG, HK GOLDSTEIN, ML SMITH, CW AF WONG, HK GOLDSTEIN, ML SMITH, CW TI ION-CYCLOTRON HARMONIC RESONANCES DRIVEN BY ION RING-BEAM DISTRIBUTIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MHD WAVES UPSTREAM; JOVIAN BOW SHOCK; WHISTLER WAVES; INSTABILITIES; GENERATION; FORESHOCK; PLASMA AB Enhanced magnetic fluctuations with frequencies peaking at the ion cyclotron frequency and its harmonics have been observed at comet Halley and also in the upstream regions of planetary bow shocks. It is thought that these waves are generated at comets by pickup ions that are unstable to the generation of waves at harmonics of the ion cyclotron wave number. In the spacecraft frame of reference these waves are observed as harmonics of the ion cyclotron frequency. In this report we show that the ring-beam distributions of pickup ions observed in the cometary environment are capable of generating these waves if the beam speed component of the distribution (parallel to the ambient magnetic field) is much larger than the ring speed (perpendicular to the magnetic field). As the ring speed increases relative to the beam speed, other instabilities occur at the same wave number which have even larger growth rates. These additional instabilities do not lead to generation of harmonics. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP WONG, HK (reprint author), SW RES INST,DEPT SPACE SCI,SAN ANTONIO,TX 78228, USA. RI Goldstein, Melvyn/B-1724-2008 NR 13 TC 8 Z9 8 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JAN 1 PY 1991 VL 96 IS A1 BP 285 EP 288 DI 10.1029/90JA02321 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EQ741 UT WOS:A1991EQ74100026 ER PT J AU WILLIAMS, RS HALL, DK BENSON, CS AF WILLIAMS, RS HALL, DK BENSON, CS TI ANALYSIS OF GLACIER FACIES USING SATELLITE TECHNIQUES SO JOURNAL OF GLACIOLOGY LA English DT Article ID INSITU AB The different snow and ice types on a glacier may be subdivided according to the glacier-facies concept. The surficial expression of some facies may be detected at the end of the balance year by the use of visible and near-infrared image data from the Landsat multispectral scanner (MSS) and thematic mapper (TM) sensors. Ice and snow can be distinguished by reflectivity differences in individual or ratioed TM bands on Bruarjokull, an outlet glacier on the northern margin of the Vatnajokull ice cap, Iceland. The Landsat scene shows the upper limit of wet snow on 24 August 1986. Landsat-derived reflectance is lowest for exposed ice and increases markedly at the transient snow line. Above the slush zone is a gradual increase in near-infrared reflectance as a result of decreasing grain-size of the snow, which characterizes drier snow. Landsat data are useful in measuring the areal extent of the ice facies, the slush zone within the wet-snow facies (combined wetsnow, percolation and dry-snow facies), and the respective positions of the transient snow line and the slush limit. In addition, fresh snowfall and/or airborne contaminants, such as soot and tephra, can limit the utility of Landsat data for delineation of the glacier facies in some cases. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH CODE 974,GREENBELT,MD 20771. UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99775. RP WILLIAMS, RS (reprint author), US GEOL SURVEY,914 NATL CTR,RESTON,VA 22092, USA. RI Hall, Dorothy/D-5562-2012 NR 35 TC 82 Z9 85 U1 5 U2 13 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1991 VL 37 IS 125 BP 120 EP 128 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA GD474 UT WOS:A1991GD47400015 ER PT J AU STURM, M HALL, DK BENSON, CS FIELD, WO AF STURM, M HALL, DK BENSON, CS FIELD, WO TI NON-CLIMATIC CONTROL OF GLACIER-TERMINUS FLUCTUATIONS IN THE WRANGELL AND CHUGACH MOUNTAINS, ALASKA, USA SO JOURNAL OF GLACIOLOGY LA English DT Article ID VARIEGATED GLACIER; SURGE; FLOW AB Fluctuations of glacier termini were studied in two regions in Alaska. In the Wrangell Mountains, 15 glaciers on Mount Wrangell, an active volcano, have been monitored over the past 30 years by surveying, photogrammetry and satellite. Results, which are consistent between different methods of measurement, indicate that the termini of most glaciers were stationary or retreating slightly. However, the termini of the 30 km long Ahtna Glacier and the smaller Center and South MacKeith Glaciers began to advance in the early 1960s and have advanced steadily between 5 and 18 m a-1 since then. These three glaciers flow from the active North Crater, where increased volcanic heating since 1964 has melted over 7 x 10(7) m3 of ice. We suspect that volcanic meltwater has changed the basal conditions for the three glaciers, resulting in their advance. The terminus fluctuations of six tide-water and near-tide-water glaciers in College Fjord, Prince William Sound, have been monitored since 1931 by surveying, photogrammetry and, most recently, by satellite imagery. Harvard Glacier, a 40 km long tide-water glacier, has been advancing at an average rate of nearly 20 m a-1 since 1931, while the adjacent Yale Glacier has retreated at approximately 50 m a-1 during the same period though, for short periods, both of these rates have been much higher. The striking contrast between the terminus behavior of Yale and Harvard Glaciers, which parallel each other in the same fiord, and are derived from the same snowfield, supports the hypothesis that their terminus behavior is largely the result of dynamic controls rather than changes in climate. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99775. AMER GEOG SOC,NEW YORK,NY. RP STURM, M (reprint author), USA,COLD REG RES & ENGN LAB,FT WAINWRIGHT,AK 99703, USA. RI Hall, Dorothy/D-5562-2012 NR 49 TC 19 Z9 19 U1 0 U2 3 PU INT GLACIOL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0022-1430 J9 J GLACIOL JI J. Glaciol. PY 1991 VL 37 IS 127 BP 348 EP 356 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA HA222 UT WOS:A1991HA22200007 ER PT J AU HATCHER, CO NESTER, RT MUTH, KM AF HATCHER, CO NESTER, RT MUTH, KM TI USING LARVAL FISH ABUNDANCE IN THE ST CLAIR AND DETROIT RIVERS TO PREDICT YEAR-CLASS STRENGTH OF FORAGE FISH IN LAKES HURON AND ERIE SO JOURNAL OF GREAT LAKES RESEARCH LA English DT Article DE FISH POPULATIONS; ALEWIFE; SHAD; SMELT; LAKE HURON; LAKE ERIE; ST CLAIR RIVER; DETROIT RIVER ID ALEWIVES AB Larval fish samples were collected in plankton tow nets in spring and summer, 1977-1978 and 1983-1984, in the St. Clair and Detroit rivers which are part of the connecting waterway between Lakes Huron and Erie. Larvae abundance of the major forage fish in the rivers are compared with their year-class abundance, as measured by bottom trawl catches of later life stages in Lakes Huron and Erie. Abundance of rainbow smelt, Osmerus mordax, and alewife, Alosa pseudoharengus, larvae in the St. Clair River in adjacent years of the 4-year study was correlated with the abundance of yearlings captured in bottom trawls in lower Lake Huron in the spring of the following years. Abundance of locally produced larval rainbow smelt, alewives, and gizzard shad, Dorosoma cepedianum, in the Detroit River in adjacent years was correlated with the abundance of young-of-the-year captured in bottom trawls in western Lake Erie the following fall. Sampling fish larvae in the main channels of the St. Clair and Detroit rivers thus provided a potential early index of forage fish abundance in the lakes. C1 NASA,PLUM BROOK STN,SANDUSKY BIOL STN,US FISH & WILDLIFE SERV,SANDUSKY,OH 44870. RP HATCHER, CO (reprint author), NATL FISHERIES RES CTR GREAT LAKES,US FISH & WILDLIFE SERV,1451 GREEN RD,ANN ARBOR,MI 48105, USA. NR 17 TC 10 Z9 10 U1 0 U2 4 PU INT ASSOC GREAT LAKES RES PI ANN ARBOR PA 2200 BONISTEEL BLVD, ANN ARBOR, MI 48109-2099 SN 0380-1330 J9 J GREAT LAKES RES JI J. Gt. Lakes Res. PY 1991 VL 17 IS 1 BP 74 EP 84 PG 11 WC Environmental Sciences; Limnology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA FJ254 UT WOS:A1991FJ25400008 ER PT J AU WU, SC YUNCK, TP THORNTON, CL AF WU, SC YUNCK, TP THORNTON, CL TI REDUCED-DYNAMIC TECHNIQUE FOR PRECISE ORBIT DETERMINATION OF LOW EARTH SATELLITES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID GRAVITY MODEL AB Observations of the global positioning system (GPS) will enable a reduced-dynamic technique for achieving subdecimeter orbit determination of low Earth satelites. With this technique, the transition between satellite states at different observing times is furnished by both a formal dynamic model and observed satellite positional change inferred kinematically from continuous GPS carrier phase data. The relative weighting of dynamic and kinematic information can be freely varied. Covariance studies show that in situations where observing geometry is poor and the dynamic model is good, the model dominates determination of the state transition; where the dynamic model is poor and the geometry strong, carrier phase governs the transition. When neither kinematic nor dynamic information is clearly superior, the reduced-dynamic combination can substantially improve the orbit solution. Guidelines are given here for selecting a near-optimal weighting for the reduced-dynamic solution, and sensitivity of solution accuracy to this weighting is examined. RP WU, SC (reprint author), CALTECH,JET PROP LAB,TRACKING SYST & APPLICAT SECT,PASADENA,CA 91109, USA. NR 17 TC 70 Z9 76 U1 3 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 24 EP 30 DI 10.2514/3.20600 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500003 ER PT J AU PARK, KC BELVIN, WK AF PARK, KC BELVIN, WK TI PARTITIONED SOLUTION PROCEDURE FOR CONTROL-STRUCTURE INTERACTION SIMULATIONS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SYSTEMS AB A partitioned computational procedure is presented for the simulation of control-structure interaction systems by employing three modular software packages: a second-order structural dynamics analyzer, a second-order observer module, and a first-order stabilized active control force generator. This paper focuses on modular programming of the procedure, techniques for enhancing accuracy and for stabilizing the partitioned interaction equations, and time discretization of the stabilized systems of equations. A stability analysis has been performed using a set of model interaction equations, which indicates that the computational stability of the procedure is governed by the highest frequency of the controller and the strength of its position feedback parameter and not by that of the structural system. Comparison of the computational efficiency of the present procedure with a first-order conventional solution procedure indicates that the present procedure offers a substantial efficiency improvement. The effectiveness of the present procedure has been demonstrated by several example problems. C1 NASA,LANGLEY RES CTR,SPACE DYNAM BRANCH,HAMPTON,VA 23665. RP PARK, KC (reprint author), UNIV COLORADO,CTR SPACE STRUCTURES & CONTROL,BOULDER,CO 80309, USA. RI park, k.c./E-8898-2010 NR 33 TC 7 Z9 7 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 59 EP 67 DI 10.2514/3.20605 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500008 ER PT J AU GAWRONSKI, W WILLIAMS, T AF GAWRONSKI, W WILLIAMS, T TI MODEL-REDUCTION FOR FLEXIBLE SPACE STRUCTURES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID PRINCIPAL COMPONENT ANALYSIS; MODAL COST-ANALYSIS; LINEAR-SYSTEMS AB This paper presents the conditions under which modal truncation yields a near-optimal reduce-order model for a flexible structure. Next, a robust model reduction technique is developed to cope with the damping uncertainties typical of a flexible space structure. Finally, a flexible truss and the Control of Flexible Structures-1 mast are used to give realistic applications for the model reduction techniques studied in this paper. C1 UNIV CINCINNATI,DEPT AEROSP ENGN & ENGN MECH,CINCINNATI,OH 45221. RP GAWRONSKI, W (reprint author), CALTECH,JET PROP LAB,GROUND ANTENNAS & FACILITIES ENGN SECT,PASADENA,CA 91109, USA. NR 22 TC 31 Z9 38 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 68 EP 76 DI 10.2514/3.20606 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500009 ER PT J AU HU, A TAYLOR, LW SINGH, RP AF HU, A TAYLOR, LW SINGH, RP TI SPECIAL-CLASS OF NONLINEAR DAMPING MODELS IN FLEXIBLE SPACE STRUCTURES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB A special class of nonlinear damping models is investigated in which the damping force is proportional to the product of positive integer or the fractional power of the absolute values of displacement and velocity. For a one-degree-of-freedom system, the classical Krylov-Bogoliubov "averaging" method is used, whereas for a distributed system, both an ad hoc perturbation technique and the finite difference method are employed to study the effects of nonlinear damping. The results are compared with linear viscous damping models. The amplitude decrement of free vibration for a single mode system with nonlinear models depends not only on the damping ratio but also on the initial amplitude, the time to measure the response, the frequency of the system, and the powers of displacement and velocity. For the distributed system, the action of nonlinear damping is found to reduce the energy of the system and to pass energy to lower modes. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP HU, A (reprint author), DYNACS ENGN CORP,PALM HARBOR,FL 34684, USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 77 EP 83 DI 10.2514/3.20607 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500010 ER PT J AU WOODARD, SE HOUSNER, JM AF WOODARD, SE HOUSNER, JM TI NONLINEAR BEHAVIOR OF A PASSIVE ZERO-SPRING-RATE SUSPENSION SYSTEM SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Various concepts for advanced suspension systems have been proposed for counteracting gravity loads in ground vibration testing of large space structures. Approximating the flight modes of a low-frequency flexible structure in a ground test requires a very soft suspension system. The dynamic behavior of a passive zero-spring-rate mechanism, sometimes used for such ground testing, is analyzed. This mechanism reduces the stiffness inherent in suspending a test specimen by cables. However, the mechanism is shown to be sensitive to imperfections. Imperfections can initiate nonlinear behavior, which becomes more pronounced at lower operating frequencies. Furthermore, large pendular motion of the suspension system couples with the vertical motion, producing additional nonlinearity. RP WOODARD, SE (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23665, USA. NR 4 TC 13 Z9 15 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 84 EP 89 DI 10.2514/3.20608 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500011 ER PT J AU GARG, S MATTERN, DL BULLARD, RE AF GARG, S MATTERN, DL BULLARD, RE TI INTEGRATED FLIGHT PROPULSION CONTROL-SYSTEM DESIGN BASED ON A CENTRALIZED APPROACH SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT CONF ON GUIDANCE, NAVIGATION, AND CONTROL CY AUG 14-16, 1989 CL BOSTON, MA SP AMER INST AERONAUT & ASTRONAUT ID METHODOLOGY AB In this paper an integrated flight/propulsion control system design is presented for the piloted longitudinal landing task with a modern, statically unstable, fighter aircraft. A centralized compensator based on the linear quadratic Gaussian/loop transfer recovery methodology is first obtained to satisfy the feedback loop performance and robustness specifications. This high-order centralized compensator is then partitioned into airframe and engine "subcontrollers" based on modal controllability/observability for the compensator modes, and the subcontrollers are further reduced in order and simplified. These subcontrollers have the advantage that they can be implemented as separate controllers on the airframe and the engine while still retaining the important performance and stability characteristics of the full-order centralized compensator. Command prefilters are then designed for the closed-loop system, and the overall system performance evaluation results are presented. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP GARG, S (reprint author), SVERDUP TECHNOL INC,LEWIS RES CTR GRP,CLEVELAND,OH 44135, USA. NR 24 TC 9 Z9 10 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 107 EP 116 DI 10.2514/3.20611 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500014 ER PT J AU BERRY, DT AF BERRY, DT TI NATIONAL AEROSPACE PLANE LONGITUDINAL LONG-PERIOD DYNAMICS SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note RP BERRY, DT (reprint author), NASA,AMES RES CTR,DRYDEN FLIGHT RES FACIL,VEHICLE TECHNOL BRANCH,EDWARDS AFB,CA 93523, USA. NR 3 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 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 205 EP 206 DI 10.2514/3.20623 PG 2 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500026 ER PT J AU ROITHMAYR, CM AF ROITHMAYR, CM TI CONTRIBUTION OF ZONAL HARMONICS TO GRAVITATIONAL MOMENT SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note RP ROITHMAYR, CM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,GUIDANCE & NAVIGAT BRANCH,HOUSTON,TX 77058, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 210 EP 214 DI 10.2514/3.20626 PG 5 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500029 ER PT J AU LANDIS, GA HRACH, FJ AF LANDIS, GA HRACH, FJ TI SATELLITE RELOCATION BY TETHER DEPLOYMENT SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note RP LANDIS, GA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 8 TC 6 Z9 6 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD JAN-FEB PY 1991 VL 14 IS 1 BP 214 EP 216 DI 10.2514/3.20627 PG 3 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA EW675 UT WOS:A1991EW67500030 ER PT J AU LANE, HW STRENGTH, R JOHNSON, J WHITE, M AF LANE, HW STRENGTH, R JOHNSON, J WHITE, M TI EFFECT OF CHEMICAL FORM OF SELENIUM ON TISSUE GLUTATHIONE-PEROXIDASE ACTIVITY IN DEVELOPING RATS SO JOURNAL OF NUTRITION LA English DT Article DE SELENOMETHIONINE; SELENOCYSTINE; SELENITE; RATS; GLUTATHIONE PEROXIDASE ID SELENOCYSTEINE; SELENOMETHIONINE; PROTEINS AB Two experiments were conducted to determine the effect of various forms of selenium (Se) on the activity of glutathione peroxidase (GSHPx) in liver, heart, kidney and eyes of the developing rat. In experiment 1, throughout mating, pregnancy and lactation, female rats consumed one of three diets: basal (< 0.05-mu-g Se/g); selenite (0.15-mu-g Se/g) and selenomethionine (0.15-mu-g Se/g). Some pups born to dams in the basal group were also given intraperitoneal doses of saline, selenite or selenomethionine. GSHPx activity was measured in tissues from fetuses, 7-d-old and 14-d-old nursing pups and the dams. In all tissues studied, GSHPx activity was highest in the 14-d-old pups whose mothers were in the selenomethionine group. Rat pups given intraperitoneal selenite (3-mu-g/kg body weight) had higher liver and kidney GSHPx activity than pups given the same amount of selenium as intraperitoneal selenomethionine. In experiment 2, all dams were fed the same basal diet, and pups were weaned to diets containing one of two levels of selenium (0.1 or 0.2-mu-g/g), one of three forms of selenium (selenite, selenomethionine or selenocystine) or no added selenium. After 14 d of repletion, the highest level of hepatic GSHPx activity occurred in the selenite group and the lowest in the basal diet group. After 21 d of repletion, renal GSHPx activity was lowest in the basal group followed by the selenocystine group. The highest tissue selenium concentration was found in kidney tissues of the selenocystine group. These data support the hypothesis that these dietary forms of selenium are differentially available for GSHPx activity. C1 AUBURN UNIV,ALABAMA AGR EXPT STN,DEPT ANIM & DAIRY SCI,AUBURN,AL 36849. NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. RP LANE, HW (reprint author), AUBURN UNIV,ALABAMA AGR EXPT STN,DEPT NUTR & FOODS,AUBURN,AL 36849, USA. NR 24 TC 22 Z9 22 U1 0 U2 0 PU AMER INST NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0022-3166 J9 J NUTR JI J. Nutr. PD JAN PY 1991 VL 121 IS 1 BP 80 EP 86 PG 7 WC Nutrition & Dietetics SC Nutrition & Dietetics GA EV589 UT WOS:A1991EV58900010 PM 1992061 ER PT J AU SCHLOSSER, H FERRANTE, J AF SCHLOSSER, H FERRANTE, J TI THE ANALYSIS OF HIGH-PRESSURE EXPERIMENTAL-DATA SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Note DE EQUATION OF STATE; PHASE TRANSITION; DATA ANALYSIS; GLASS; MANGANESE OXIDE; CALCIUM ID BINDING-ENERGY RELATION; EQUATION; METALS; STATE; CHEMISORPTION AB This letter is concerned with the analysis of high pressure experimental data. We demonstrate that ln H plots based on the Vinet et al. universal equation of state (EOS) are a simple sensitive means for identifying anomalous P-V data in high pressure experiments, and for detecting structural and phase transitions in solids subjected to high pressure. C1 NATL AERONAUT & SPACE ADM,LEWIS RES CTR,CLEVELAND,OH 44135. RP SCHLOSSER, H (reprint author), CLEVELAND STATE UNIV,DEPT PHYS,CLEVELAND,OH 44115, USA. NR 18 TC 4 Z9 4 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PY 1991 VL 52 IS 4 BP 635 EP 637 DI 10.1016/0022-3697(91)90159-W PG 3 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA FD276 UT WOS:A1991FD27600012 ER PT J AU BERLAD, AL TANGIRALA, V ROSS, H FACCA, L AF BERLAD, AL TANGIRALA, V ROSS, H FACCA, L TI RADIATIVE STRUCTURES OF LYCOPODIUM-AIR FLAMES IN LOW GRAVITY SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Initially uniform clouds of fuel particulates in air sustain processes which may lead to particle-cloud nonuniformities. In low gravity, flame-induced Kundt's tube phenomena are observed to form regular patterns of nonuniform particle concentrations. Irregular patterns of particle concentrations also are observed to result from selected nonuniform mixing processes. Low-gravity flame propagation for each of these classes of particle-cloud flames has been found to depend importantly on the flame-generated infrared radiative fields. The spatial structures of these radiative fields are described. Application is made for the observed cases of lycopodium-air flames. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP BERLAD, AL (reprint author), UNIV CALIF SAN DIEGO,CTR ENERGY & COMBUST RES,LA JOLLA,CA 92093, USA. NR 10 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 5 EP 8 DI 10.2514/3.23286 PG 4 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900002 ER PT J AU CHITSOMBOON, T NORTHAM, GB AF CHITSOMBOON, T NORTHAM, GB TI COMPUTATIONAL FLUID-DYNAMICS PREDICTION OF THE REACTING FLOWFIELD INSIDE A SUBSCALE SCRAMJET COMBUSTOR SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 24TH JOINT PROPULSION CONF CY JUL 11-13, 1988 CL BOSTON, MA SP AMER INST AERONAUT & ASTRONAUT, AMER SOC MECH ENGINEERS, SOC AUTOMOT ENGINEERS, AMER SOC ENGN EDUC AB A three-dimensional, Reynolds-averaged Navier-Stokes computational fluid dynamics (CFD) code has been used to calculate the reacting flowfield inside a hydrogen-fueled subscale scramjet combustor. Pilot fuel was injected transversely upstream of the combustor, and the primary fuel was injected transversely downstream of a backward facing step. A finite-rate combustion model with two-step kinetics was used. The CFD code used the explicit MacCormack algorithm with point implicit treatment of the chemistry source terms. Turbulent mixing of the jets with the airstream was simulated by a simple mixing length scheme, whereas near-wall turbulence was accounted for by the Baldwin-Lomax model. Computed results were compared with experimental wall pressure measurements. C1 VIGYAN INC,HAMPTON,VA 23665. NASA,LANGLEY RES CTR,DIV FLUID MECH,EXPTL METHODS BRANCH,HAMPTON,VA 23665. NR 5 TC 4 Z9 5 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 44 EP 48 DI 10.2514/3.23292 PG 5 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900008 ER PT J AU CARNEY, LM BAILEY, AB AF CARNEY, LM BAILEY, AB TI EXPERIMENTAL EVALUATION OF RESISTOJET THRUSTER PLUME SHIELDS SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The exhaust plume characteristics of an engineering model resistojet have been evaluated using rotary pitot and quartz crystal microbalance probes. The resistojet operated on CO2 propellant at a mass flow rate of 0.29 g/s in both heated and unheated flows. Measurements of local flow angles in the near field of a conical plume shield indicated that the shield was not wholly effective in confining the flow to the region downstream of its exit plane. However, the absolute levels of the measured flux into the backflow region were very low, on the order of 7 x 10(-7) g/cm2-S or less. The use of a circular disk at the exit plane of the existing conical shield showed some benefit in decreasing the amount of backflow by a factor of 2. Last, a detached shield placed upstream of the resistojet exit plane demonstrated a small degree of local shielding for the region directly behind it. C1 CALSPAN CORP,TULLAHOMA,TN 37389. ARNOLD ENGN DEV CTR,SPACE SYST BRANCH,ARNOLD AFB,TN. RP CARNEY, LM (reprint author), NASA,LEWIS RES CTR,DIV SPACE PROP TECHNOL,CLEVELAND,OH 44135, USA. NR 12 TC 0 Z9 0 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 49 EP 55 DI 10.2514/3.23293 PG 7 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900009 ER PT J AU SOVEY, JS MANTENIEKS, MA AF SOVEY, JS MANTENIEKS, MA TI PERFORMANCE AND LIFETIME ASSESSMENT OF MAGNETOPLASMADYNAMIC ARC-THRUSTER TECHNOLOGY SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 24TH JOINT PROPULSION CONF CY JUL 11-13, 1988 CL BOSTON, MA SP AMER INST AERONAUT & ASTRONAUT, AMER SOC MECH ENGINEERS, SOC AUTOMOT ENGINEERS, AMER SOC ENGN EDUC ID MPD THRUSTER; EROSION; CATHODE AB A summary of performance and lifetime characteristics of pulsed and steady-state magnetoplasmadynamic (MPD) thrusters is presented. The technical focus is on cargo vehicle propulsion for exploration-class missions to the moon and Mars. Relatively high MPD thruster efficiencies of 0.43 and 0.69 have been reported at about 5000-s specific impulse using hydrogen and lithium, respectively. Efficiencies of 0.10 to 0.35 in the 1000-to 4500-s specific impulse range have been obtained with other propellants (e.g., Ar, NH3, N2). Electrode power losses of less than 20% at megawatt power levels using pulsed thrusters indicate the potential of high MPD thruster performance. Extended tests of pulsed and steady-state MPD thrusters yield total impulses at least two to three orders of magnitude below that necessary for cargo vehicle propulsion. Performance tests and dignostics for life-limiting mechanisms of megawatt-class thrusters will require high-fidelity test stands, which handle in excess of 10 KA, and a vacuum facility whose operational pressure is less than 4 x 10(-2) Pa. RP SOVEY, JS (reprint author), NASA,LEWIS RES CTR,DIV SPACE PROP TECHNOL,CLEVELAND,OH 44135, USA. NR 64 TC 30 Z9 31 U1 1 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 71 EP 83 DI 10.2514/3.23296 PG 13 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900012 ER PT J AU REDDY, DR HARLOFF, GJ AF REDDY, DR HARLOFF, GJ TI 3-DIMENSIONAL VISCOUS-FLOW COMPUTATIONS OF HIGH AREA RATIO NOZZLES FOR HYPERSONIC PROPULSION SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The PARC3D code was selected by the authors to analyze a variety of complex and high-speed flow configurations. Geometries considered for code validation include ramps and corner flows, which are characteristic of inlets and nozzles. Flows with Mach numbers of 3-14 were studied. Both two- and three-dimensional experimental data for shock-boundary-layer interaction were considered to validate the code. A detailed comparison of various flow parameters with available experimental data is presented; agreement between the solutions and the experimental data in terms of pitot pressure profiles, yaw-angle distrobutions, static pressures, and skin friction is found to be very good. In addition, two- and three-dimensional flow calculations were performed for a hypersonic nozzle. Comparison of the wall pressure results with the publushed solutions is made for the two-dimensional case. RP REDDY, DR (reprint author), NASA,LEWIS RES CTR GRP,SVERDRUP TECHNOL INC,TURBOMACHINERY ANAL SECT,BROOK PK,OH 44142, USA. NR 20 TC 2 Z9 2 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 84 EP 89 DI 10.2514/3.23297 PG 6 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900013 ER PT J AU MEHMED, O MURTHY, DV AF MEHMED, O MURTHY, DV TI EXPERIMENTAL INVESTIGATION OF PROPFAN AEROELASTIC RESPONSE IN OFF-AXIS FLOW WITH MISTUNING SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 24TH JOINT PROPULSION CONF CY JUL 11-13, 1988 CL BOSTON, MA SP AMER INST AERONAUT & ASTRONAUT, AMER SOC MECH ENGINEERS, SOC AUTOMOT ENGINEERS, AMER SOC ENGN EDUC ID BLADED-DISK; VIBRATION AB Measured vibratory strain amplitudes resulting from off-axis flow are compared for the blades of two eight-bladed, 0.62-m-(2-ft-) diam propfan model rotors with mistuning. One rotor had inherent mistuning. The other was intentionally misturned by replacing every other blade of the first rotor with a blade of same geometry but different frequencies and mode shapes. The data show that the intentional mistuning had a benficial effect on the aeroelastic response of the propfan blades for a wide range of off-axis flow angles, blade pitch angles, and rotational speeds. The data also illustrate that large and intuitively unpredictable variations in the aeroelastic response of propfan blades can occur because of inherent mistuning. Statistical trends of blade strain amplitudes are compared for both the rotors in terms of the ratio of the maximum to the mean. C1 UNIV TOLEDO,TOLEDO,OH 43606. RP MEHMED, O (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 15 TC 1 Z9 1 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 90 EP 98 DI 10.2514/3.23298 PG 9 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900014 ER PT J AU LANDIS, GA LU, CY AF LANDIS, GA LU, CY TI SOLAR-ARRAY ORIENTATIONS FOR A SPACE STATION IN LOW EARTH ORBIT SO JOURNAL OF PROPULSION AND POWER LA English DT Note C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44115. NATL RES COUNCIL,WASHINGTON,DC 20418. RP LANDIS, GA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JAN-FEB PY 1991 VL 7 IS 1 BP 123 EP 125 DI 10.2514/3.23302 PG 3 WC Engineering, Aerospace SC Engineering GA FE929 UT WOS:A1991FE92900018 ER PT J AU CHAMIS, CC MURTHY, PLN AF CHAMIS, CC MURTHY, PLN TI SIMPLIFIED PROCEDURES FOR DESIGNING ADHESIVELY BONDED COMPOSITE JOINTS SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article AB Procedures for the preliminary design of composite adhesive joints are described. Typical joints, their respective free body diagrams and approximate equations for estimating the stresses in each of these typical joints are summarized. Equations are also presented to check the critical conditions of the joint, such as: minimum length, maximum adhesive shear stress and peel-off stress. To illustrate the procedure, sample designs are described in step-by-step fashion for a butt joint with single doubler subjected to static loads, cyclic loads and environmental effects. The results show that (1) unsymmetric adhesive joints are insufficient and should be avoided, and (2) hygrothermal environments and cyclic loads dramatically reduce the structural integrity of the joint and require several joint lengths compared to those for static load with no environmental effects. RP CHAMIS, CC (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 20 Z9 21 U1 0 U2 2 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 JAN PY 1991 VL 10 IS 1 BP 29 EP 41 DI 10.1177/073168449101000102 PG 13 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA EP268 UT WOS:A1991EP26800002 ER PT J AU SIMONSEN, LC NEALY, JE TOWNSEND, LW WILSON, JW AF SIMONSEN, LC NEALY, JE TOWNSEND, LW WILSON, JW TI MARTIAN REGOLITH AS SPACE RADIATION SHIELDING SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note AB IN current Mars scenario descriptions, an entire mission is estimated to take 500-1000 days round trip with a 100-600 day stay time on the surface. To maintain radiation dose levels below permissible limits, dose estimates must be determined for the entire mission length. With extended crew durations anticipated on Mars, the characterization of the radiation environment on the surface becomes a critical aspect of mission planning. The most harmful free-space radiation is due to high energy galactic cosmic rays (GCR) and solar flare protons. The carbon dioxide atmosphere of Mars has been estimated to provide a sufficient amount of shielding from these radiative fluxes to help maintain incurred doses below permissible limits. 1,2 However, Mars exploration crews are likely to incur a substantial dose while in transit to Mars that will reduce the allowable dose that can be received while on the surface. Therefore, additional shielding may be necessary to maintain short-term dose levels below limits or to help maintain career dose levels as low as possible. By utilizing local resources, such as Martian regolith, shielding materials can be provided without excessive launch weight requirements from Earth. The scope of this synopsis and of Ref. 3 focuses on presenting our estimates of surface radiation doses received due to the transport and attenuation of galactic cosmic rays and February 1956 solar flare protons through the Martian atmosphere and through additional shielding provided by Martian regolith. RP SIMONSEN, LC (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,HAMPTON,VA 23665, USA. NR 8 TC 8 Z9 8 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 7 EP 8 DI 10.2514/3.26201 PG 2 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500002 PM 11537624 ER PT J AU BLAIR, AB AF BLAIR, AB TI SUPERSONIC AERODYNAMIC CHARACTERISTICS OF MONOPLANAR MISSILES WITH LOW-PROFILE QUADRIFORM TAILS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Wind-tunnel tests were conducted on monoplanar circular missile configurations with low-profile quadriform tail fins to provide an aerodynamic data base to study and evaluate air-launched missile candidates for efficient conformal carriage on supersonic-cruise-type aircraft. The tests were conducted in the NASA Langley Unitary Plan Wind Tunnel at Mach numbers 1.70-2.86 for a constant Reynolds number per foot of 2.00 x 10(6). Selected test results are presented to show the effects of tail-fin dihedral angle, wing longitudinal and vertical location, and nose-body strakes on the static longitudinal and lateral-directional aerodynamic stability and control characteristics. RP BLAIR, AB (reprint author), NASA,LANGLEY RES CTR,DIV APPL AERODYNAM,SUPERSON HYPERSON AERODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 9 EP 15 DI 10.2514/3.26202 PG 7 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500003 ER PT J AU WURSTER, KE ZOBY, EV THOMPSON, RA AF WURSTER, KE ZOBY, EV THOMPSON, RA TI FLOWFIELD AND VEHICLE PARAMETER INFLUENCE ON RESULTS OF ENGINEERING AEROTHERMAL METHODS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SHOCK-LAYER FLOWS AB Flight- and ground-test heat-transfer data, detailed predictions, and engineering solutions have been compared. The impact of several parameters on heat transfer and the capability of three engineering codes to predict these results have been demonstrated. Results have shown that fairly good agreement with data and detailed solutions can be obtained, but good engineering judgment is required in choosing the options in the codes. In particular, comparison of the results of the engineering codes, AEROHEAT, INCHES, and MINIVER, with Reentry F flight data and ground-test heat-transfer data for a range of cone angles, and with the predictions obtained using the detailed VSL3D code, has shown very good agreement in the regions of applicability of the engineering codes. The impact of several flowfield and vehicle parameters, including entropy, pressure gradient, nose bluntness, gas chemistry, and angle of attack on heating levels has been shwon to be important. Particular care must be exercised when using engineering codes since comparisons have demonstrated that the parameters of this study can significantly influence the actual heating levels and the prediction capability of a code. The engineering codes provide the user with relatively simple techniques to define the aerothermal environment for parametric or preliminary design studies. RP WURSTER, KE (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,HAMPTON,VA 23665, USA. NR 36 TC 9 Z9 10 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 16 EP 22 DI 10.2514/3.26203 PG 7 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500004 ER PT J AU PARK, C YOON, S AF PARK, C YOON, S TI FULLY COUPLED IMPLICIT METHOD FOR THERMOCHEMICAL NONEQUILIBRIUM AIR AT SUBORBITAL FLIGHT SPEEDS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A computational fluid dynamics (CFD) technique is described in which the finite-rate chemistry in thermal and chemical nonequilibrium air is fully and implicitly coupled with the fluid motion. Developed for use in the suborbital hypersonic flight speed range, the method accounts for the nonequilibrium vibrational and electronic excitation and dissociation but not ionization. The steady-state solution to the resulting system of equations is obtained by using a lower-upper factorization and symmetric Gauss-Seidel sweeping technique through Newton iteration. Inversion of the left-hand-side matrices is replaced by scalar multiplications through the use of the diagonal dominance algorithm. The code, named compressible Euler-Navier-Stokes two-dimensional hypersonic (CENS2H), is fully vectorized and requires about 8.8 x 10(-5) s per node point per iteration in a Cray X-MP computer. Converged solutions are obtained after about 700 iterations. Sample calculations are made for a circular cylinder and a 10% airfoil at a 10-deg angle of attack. The calculated cylinder flowfield agrees with that obtained experimentally. The code predicts a 10% change in lift and drag and a 20% change in pitching moment for the airfoil caused by the thermochemical phenomena. C1 MCAT INST,MOFFETT FIELD,CA. RP PARK, C (reprint author), NASA,AMES RES CTR,EXPTL AEROTHERMODYNAM SECT,MOFFETT FIELD,CA 94035, USA. NR 10 TC 17 Z9 17 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 31 EP 39 DI 10.2514/3.26205 PG 9 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500006 ER PT J AU TAUBER, ME SUTTON, K AF TAUBER, ME SUTTON, K TI STAGNATION-POINT RADIATIVE HEATING RELATIONS FOR EARTH AND MARS ENTRIES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Stagnation-point radiative heating rate expressions are presented for use in air and an approximate Martian atmosphere consisting of 97% CO2 and 3% N2. Thermochemical equilibrium is assumed throughout. The flight conditions and body dimensions that are modeled are representative of both manned and unmanned missions to Mars and return to Earth. Comparisons between the heating rates computed using the expressions presented here and independent computations yielded maximum differences of about 20 to 30%. C1 NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665. RP TAUBER, ME (reprint author), NASA,AMES RES CTR,AEROTHERMODYNAM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 11 TC 73 Z9 75 U1 1 U2 7 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 40 EP 42 DI 10.2514/3.26206 PG 3 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500007 ER PT J AU BRAUN, RD BLERSCH, DJ AF BRAUN, RD BLERSCH, DJ TI PROPULSIVE OPTIONS FOR A MANNED MARS TRANSPORTATION SYSTEM SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB In this investigation, a comparison of four potential manned Mars transportation systems is made. These options include 1) a single vehicle using chemical propulsion, 2) a single vehicle using nuclear thermal propulsion, 3) a single vehicle using nuclear electric and chemical propulsion, and 4) a dual vehicle (a nuclear electric cargo spacecraft and a chemical manned vehicle). In addition to utilizing the initial vehicle mass in low-Earth orbit (LEO) as a measure of mission feasibility, this study addresses the major technological barriers each propulsive scenario must surpass. It is shown that instead of a single clearly superior propulsion system, each of the four means of propulsion may be favored depending on the specified exploration policy, technology readiness level, and the acceptable manned flight time. The effect that aerobraking has on mission feasibility is also considered. Although the use of aerobraking at both Earth and Mars is shown to make chemical propulsion more competitive with the other means of transportation, this option is still not optimal from an initial LEO mass standpoint. This study also shows that the reduced initial LEO mass requirements associated with both aerobraking and nuclear thermal propulsion do not necessarily supplement each other. C1 ANALYT SERV INC,DIV SPACE TECHNOL,ARLINGTON,VA 22202. RP BRAUN, RD (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,HAMPTON,VA 23665, USA. NR 16 TC 12 Z9 12 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 85 EP 92 DI 10.2514/3.26213 PG 8 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500014 ER PT J AU HAMILTON, HH GUPTA, RN JONES, JJ AF HAMILTON, HH GUPTA, RN JONES, JJ TI FLIGHT STAGNATION-POINT HEATING CALCULATIONS ON AEROASSIST FLIGHT EXPERIMENT VEHICLE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 SCI RES & TECHNOL INC,HAMPTON,VA 23693. RP HAMILTON, HH (reprint author), NASA,LANGLEY RES CTR,ANALYT MECH ASSOCIATES,HAMPTON,VA 23665, USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD JAN-FEB PY 1991 VL 28 IS 1 BP 125 EP 128 DI 10.2514/3.26219 PG 4 WC Engineering, Aerospace SC Engineering GA FH225 UT WOS:A1991FH22500020 ER PT J AU BAILEY, DH LEE, K SIMON, HD AF BAILEY, DH LEE, K SIMON, HD TI USING STRASSEN ALGORITHM TO ACCELERATE THE SOLUTION OF LINEAR-SYSTEMS SO JOURNAL OF SUPERCOMPUTING LA English DT Article AB Strassen's algorithm for fast matrix-matrix multiplication has been implemented for matrices of arbitrary shapes on the CRAY-2 and CRAY Y-MP supercomputers. Several techniques have been used to reduce the scratch space requirement for this algorithm while simultaneously preserving a high level of performance. When the resulting Strassen-based matrix multiply routine is combined with some routines from the new LAPACK library, LU decomposition can be performed with rates significantly higher than those achieved by conventional means. We succeeded in factoring a 2048 x 2048 matrix on the CRAY Y-MP at a rate equivalent to 325 MFLOPS. C1 CALIF STATE UNIV,DEPT COMP SCI,BAKERSFIELD,CA 93309. RP BAILEY, DH (reprint author), NASA,AMES RES CTR,MAIL STOP T045-1,COMP SCI CORP,MOFFETT FIELD,CA 94035, USA. NR 12 TC 6 Z9 6 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-8542 J9 J SUPERCOMPUT JI J. Supercomput. PD JAN PY 1991 VL 4 IS 4 BP 357 EP 371 DI 10.1007/BF00129836 PG 15 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA EX622 UT WOS:A1991EX62200003 ER PT J AU CANTRELL, JH YOST, WT AF CANTRELL, JH YOST, WT TI DIAGNOSIS OF BURNS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Note RP CANTRELL, JH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JAN PY 1991 VL 89 IS 1 BP 467 EP 467 DI 10.1121/1.400487 PG 1 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA ER162 UT WOS:A1991ER16200056 ER PT J AU MOSHER, M AF MOSHER, M TI LOW-FREQUENCY ROTATIONAL NOISE IN CLOSED-TEST-SECTION WIND TUNNELS SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB Harmonic rotor noise inside a closed-test-section wind tunnel is studied with a computational model. In a typical test, the rotor spins at full-scale tip Mach number and occupies about half the wind tunnel width. With these parameters a full-scale 4-bladed main rotor has a fundamental acoustic frequency of around 20 Hz. Wall treatments absorb little acoustic energy at 20 Hz; therefore, reflections modify the acoustic field of the first harmonic throughout most of the wind tunnel test section. Furthermore, this analysis shows that the difference between the sound pressure level in a wind tunnel and free-field depends on details of the wind tunnel geometry and wall absorption characteristics, source characteristics such as frequency and directivity, and observer location in the wind tunnel. Accurate low-frequency measurements of full-scale rotors cannot easily be made in existing closed-test-section wind tunnels except close to the rotor in the acoustic near field of the rotor. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 28 TC 1 Z9 1 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JAN PY 1991 VL 36 IS 1 BP 24 EP 34 PG 11 WC Engineering, Aerospace SC Engineering GA EX311 UT WOS:A1991EX31100003 ER PT J AU CHOY, FK TU, YK SAVAGE, M TOWNSEND, DP AF CHOY, FK TU, YK SAVAGE, M TOWNSEND, DP TI VIBRATION SIGNATURE AND MODAL-ANALYSIS OF MULTISTAGE GEAR TRANSMISSION SO JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS LA English DT Article ID ROTOR AB An analysis is presented for multi-stage multi-mesh gear transmission systems which predicts the overall system dynamics and transmissibility to the gear box or the enclosed structure. The modal synthesis approach of the analysis treats the uncoupled lateral/torsional modal characteristics of each stage or component independently. The vibration signature analysis evaluates the global dynamics coupling in the system. The method synthesizes the interaction of each modal component or stage with nonlinear gear mesh dynamics and modal support geometry characteristics. The analysis simulates transient and steady state vibration events due to torque variations, speed changes, rotor imbalances and gear box support motion excitations. A vibration signature analysis scheme examines the overall dynamic characteristics of the system, and the individual modal component responses. The gear box vibration analysis also examines the spectral characteristics of the support system. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CHOY, FK (reprint author), UNIV AKRON,DEPT MECH ENGN,AKRON,OH 44325, USA. NR 11 TC 14 Z9 14 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-0032 J9 J FRANKLIN I JI J. Frankl. Inst.-Eng. Appl. Math. PY 1991 VL 328 IS 2-3 BP 281 EP 298 DI 10.1016/0016-0032(91)90035-2 PG 18 WC Automation & Control Systems; Engineering, Multidisciplinary; Engineering, Electrical & Electronic; Mathematics, Interdisciplinary Applications SC Automation & Control Systems; Engineering; Mathematics GA FB497 UT WOS:A1991FB49700008 ER PT J AU Hansman, RJ Yamaguchi, K Berkowitz, B Potapczuk, M AF Hansman, R. John, Jr. Yamaguchi, Keiko Berkowitz, Brian Potapczuk, Mark TI Modeling of Surface Roughness Effects on Glaze Ice Accretion SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB A series of experimental investigations focused on studying the cause and effect of surface roughness on accreting glaze ice surfaces were conducted. Detailed microvideo observations were made of glaze ice accretions on 1- to 4-in.-diam cylinders in three icing wind tunnels (the Data Products of New England 6-in, test facility, the NASA Lewis Icing Research Tunnel, and the B. F. Goodrich Ice Protection Research Facility). Infrared thermal video recordings were made of accreting ice surfaces in the Goodrich facility. Distinct zones of surface water behavior were observed: a smooth wet zone in the stagnation region with a uniform water film, a rough zone where surface tension effects caused coalescence of surface water into stationary beads, a horn zone where roughness elements grow into horn shapes, a runback zone where surface water ran back as rivulets, and a dry zone where rime feathers formed. The location of the transition from the smooth to the rough zone was found to migrate with time towards the stagnation point. The behavior of the transition appeared to be controlled by boundary-layer transition and bead formation mechanisms at the interface between the smooth and rough zones. Regions of wet ice growth and enhanced heat transfer were clearly visible in the infrared video recordings of glaze ice surfaces. A simple multizone modification to the current glaze ice accretion model was proposed to include spatial variability in surface roughness. A preliminary version of this model was implemented on the LEWICE ice accretion code and compared with experimental ice shapes. For one of the cases, running the multizone model significantly improved the prediction of the glaze ice shapes. C1 [Hansman, R. John, Jr.; Yamaguchi, Keiko] MIT, Dept Aeronaut & Astronaut, Cambridge, MA 02139 USA. [Berkowitz, Brian] Sverdrup Technol Inc, Middleburg Hts, OH 44130 USA. [Potapczuk, Mark] NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hansman, RJ (reprint author), MIT, Dept Aeronaut & Astronaut, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI BERKOWITZ, BRIAN/K-1497-2012 OI BERKOWITZ, BRIAN/0000-0003-3078-1859 NR 9 TC 13 Z9 13 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN PY 1991 VL 5 IS 1 BP 54 EP 60 DI 10.2514/3.226 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA V24ZU UT WOS:000208449100009 ER PT J AU Lin, CS AF Lin, Chin-Shun TI Vapor Condensation at the Free Surface of an Axisymmetric Liquid Mixed by a Laminar Jet SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB This paper presents numerical solutions of jet-induced mixing in a partially full cryogenic tank. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady-state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of previously stated parameters on the condensation Nusselt and Stanton numbers that characterize the steady-state interface condensation process are investigated. Detailed analysis is performed to gain a better understanding of the fundamentals of fluid mixing and interface condensation. C1 NASA, Lewis Res Ctr, Analex Corp, Cryogen Fluid Technol Off, Cleveland, OH 44135 USA. RP Lin, CS (reprint author), NASA, Lewis Res Ctr, Analex Corp, Cryogen Fluid Technol Off, Cleveland, OH 44135 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN PY 1991 VL 5 IS 1 BP 69 EP 75 DI 10.2514/3.228 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA V24ZU UT WOS:000208449100011 ER PT J AU Piomelli, U Moin, P Ferziger, J AF Piomelli, Ugo Moin, Parviz Ferziger, Joel TI Large Eddy Simulation of the Flow in a Transpired Channel SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article C1 [Piomelli, Ugo] Univ Maryland, Dept Mech Engn, College Pk, MD 20742 USA. [Moin, Parviz; Ferziger, Joel] Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. [Moin, Parviz] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Piomelli, U (reprint author), Univ Maryland, Dept Mech Engn, College Pk, MD 20742 USA. FU NASA [NCC 2-15] FX This work was supported by NASA under Cooperative Agreement NCC 2-15. The authors thank John Kim of NASA Ames Research Center for many valuable discussions. NR 10 TC 8 Z9 8 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JAN PY 1991 VL 5 IS 1 BP 124 EP 128 DI 10.2514/3.238 PG 5 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA V24ZU UT WOS:000208449100021 ER PT J AU TABIBAZAR, M ABEDIN, MN ABBATE, A DAS, P AF TABIBAZAR, M ABEDIN, MN ABBATE, A DAS, P TI CHARACTERIZATION OF SEMICONDUCTOR-MATERIALS AND DEVICES USING ACOUSTOELECTRIC VOLTAGE MEASUREMENT SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID ACOUSTIC SURFACE-WAVES; SEMI-INSULATING GAAS; ELECTRICAL-PROPERTIES; SPECTROSCOPY; STATES; FILM AB During the past 20-25 years, the nondestructive surface acoustic wave (SAW) measurement technique has been developed and used to characterize the electrical properties of semiconductor materials and devices. Important semiconductor parameters such as carrier density, type and mobility, interface and fixed oxide charge densities, deep-level cross section and activation energy, and excess carrier generation and recombination lifetimes are all determined using SAW. In the majority of these experiments, separate medium structure is used where SAW is generated at the surface of a piezoelectric substrate like LiNbO3. SAW in the piezoelectric materials is accompanied by a decaying electric field which interacts with the free carriers of a semiconductor placed nearby. The spatial resolution that is usually achieved in these measurements is on the order of the SAW wavelength or the extrinsic Debye length, whichever is shorter. Variety of semiconductors are characterized using SAW including: silicon, GaAs, Al(x)Ga(1-x)As, InAs, GaP, Hg(x)Cd(1-x)Te, CdTe, InP, CdS, and InAs. More recently, high T(c) ceramic superconductors have also been studied. The most important aspect of the SAW technique is that it is nondestructive and it has very high sensitivity in studying high resistivity materials. Here, we present a review of the SAW technique discussing its application in quantitative characterization of semiconductor materials and devices. C1 NASA,LANGLEY RES CTR,NONDESTRUCTIVE MEASUREMENT SCI BRANCH,HAMPTON,VA 23665. RENSSELAER POLYTECH INST,DEPT ELECT COMP & SYST ENGN,TROY,NY 12180. RP TABIBAZAR, M (reprint author), CASE WESTERN RESERVE UNIV,DEPT ELECT ENGN & APPL PHYS,CLEVELAND,OH 44106, USA. NR 73 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JAN-FEB PY 1991 VL 9 IS 1 BP 95 EP 110 DI 10.1116/1.585796 PG 16 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA EZ169 UT WOS:A1991EZ16900013 ER PT J AU VOAS, J AF VOAS, J TI A DYNAMIC FAILURE MODEL FOR PREDICTING THE IMPACT THAT A PROGRAM LOCATION HAS ON THE PROGRAM SO LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article AB This paper presents a dynamic technique for predicting the effect that a ''location'' of a program will have on the program's computational behavior. The technique is based on the three necessary and sufficient conditions for software failure to occur: (1) a fault must be executed, (2) the fault must adversely affect the data state, and (3) the adverse effect in a data state must affect program output. In order to predict the effect that a location of a program will have on the program's computational behavior, the following characteristics of each program location are estimated: (1) the probability that a location of the program is executed, (2) the probability that a location of the program noticeably affects the program state created by the location, and (3) the probability that the data states created by a location affect the program's output. With estimates of these characteristics for each location in a program, we can predict those locations where a fault can more easily remain undetected during testing, as well as predict the degree of testing necessary to be convinced that a fault is not remaining undetected in a particular location. RP VOAS, J (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 478,HAMPTON,VA 23665, USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0302-9743 J9 LECT NOTES COMPUT SC JI Lect. Notes Comput. Sci. PY 1991 VL 550 BP 308 EP 331 PG 24 WC Computer Science, Theory & Methods SC Computer Science GA KQ177 UT WOS:A1991KQ17700017 ER PT J AU THY, P AF THY, P TI HIGH AND LOW-PRESSURE PHASE-EQUILIBRIA OF A MILDLY ALKALIC LAVA FROM THE 1965 SURTSEY ERUPTION - EXPERIMENTAL RESULTS SO LITHOS LA English DT Article ID EXPERIMENTAL PETROLOGY; MAGMA GENESIS; IRON LOSS; BASALTS; FRACTIONATION; PETROGENESIS; FORSTERITE; PERIDOTITE; LIQUIDS; ROCKS AB Melting experiments have been performed on a primitive, mildly alkalic glassy lava (10 wt.% MgO) from the 1965 eruption of the Surtsey volcano located at the tip of the south-eastern propagating rift zone of Iceland. At atmospheric pressure, approximately on the FMQ oxygen buffer, olivine (Fo81) crystallizes from 1240-degrees-C, followed by plagioclase (An70) from 1180-degrees-C and augite from 1140-degrees-C. The experimental glasses coexisting with olivine, plagioclase and augite are ferrobasaltic enriched in FeO (13.6-14.2 wt.%) and TiO2 (4.0-4.4 wt.%). In high pressure, piston-cylinder, graphite-controlled runs, olivine occurs as the liquidus phase until 14 kbar, above which augite is the liquidus phase. Low-Ca pyroxene is not a liquidus phase at any pressure. The high pressure liquids are, relative to the one atmosphere liquids, significantly enriched in Al2O3 and Na2O and depleted in CaO as a result of changes in the crystallizing assemblages. Furthermore, liquidus augite is dominantly subcalcic and shows significant enrichment in Al and depletion in Ti. Subliquidus plagioclase is enriched in sodium relative to low pressure phase compositions. Evaluated in normative projections, contrasting liquid lines of descent are revealed as a function of pressure. At one atmosphere, the multisaturated liquids are located close to the thermal divide defined by the plane olivine-plagioclase-augite, but appear, with advanced degrees of crystallization, to be moving away from the thermal divide toward normative quartz. The augites crystallizing in the one atmosphere experiments are calcic and slightly nepheline normative. In the 10 and 12.5 kbar experiments, the augites become subcalcic and dominantly hypersthene normative. Because of this shift in augite compositions, transitional basaltic liquids may at high pressure evolve from the tholeiitic side of the olivine-plagioclase-diopside normative divide onto the alkalic side. With increasing pressure above 15 kbar, the liquidus augite compositions move back toward the olivine-plagioclase-diopside normative divide. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 46 TC 59 Z9 59 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0024-4937 J9 LITHOS JI Lithos PD JAN PY 1991 VL 26 IS 3-4 BP 223 EP 243 DI 10.1016/0024-4937(91)90030-O PG 21 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA EX223 UT WOS:A1991EX22300002 ER PT J AU THY, P AF THY, P TI HIGH AND LOW-PRESSURE PHASE-EQUILIBRIA OF A MILDLY ALKALIC LAVA FROM THE 1965 SURTSEY ERUPTION - IMPLICATIONS FOR THE EVOLUTION OF MILDLY ALKALIC AND TRANSITIONAL BASALTS IN THE SOUTH-EASTERN PROPAGATING RIFT-ZONE OF ICELAND SO LITHOS LA English DT Article ID SILICATE LIQUIDS; 1 ATM; RIDGE; PETROGENESIS; THOLEIITES; PETROLOGY; GENESIS; CONSTRAINTS; GENERATION; OLIVINE AB The south-eastern propagating rift zone of Iceland shows a progression from tholeiitic, to transitional, and mildly alkalic basalts going toward the front of the propagator. A petrogenetic model has been formulated based on low and high pressure melting experiments. The evolution of the magmas behind the front of the propagating rift is dominated by near surface processes (e.g., Katla and Hekla volcanic systems). Compared with the one atmosphere liquid line of descent, the Vestmannaeyjar lavas, erupted at the front of the propagating rift, have systematically higher Al2O3 and Na2O contents consistent with the experimentally determined effects of high pressure, Labradoritic plagioclase megacrysts, which occur in the early phase of the Surtsey eruption at the front of the propagator, are consistent with the predicted effect of high pressure on plagioclase composition. On the other hand, augites similar to those of the high pressure experiments are unknown among the phenocryst and xenolith assemblages of the Vestmannaeyjar lavas (and other Icelandic lavas). Petrographic evidence points toward a high water content in the evolved lavas of the Vestmannaeyjar. A relatively high water activity and high pressure in the magma chambers at the front of the propagator could have caused a significant suppression of the liquids temperature, in particular for plagioclase. Seismic and magnetotelluric evidence suggest that magma chambers behind the propagating front occur at the depth equivalent to 2-3 kbar of pressure. At the front, magma chambers have been located by geophysical evidence at significantly greater depths equivalent to 3-8 kbar. The lavas erupted at the front of the propagator are located to the alkalic side of the thermal divide and, therefore, can be expected to evolve toward nepheline saturation under slightly hydrous conditions. The most evolved of these lavas are of ferrobasaltic compositions and may be saturated with augite. The lavas erupted behind the front are located to the transitional side of the divide and evolve toward quartz saturation under essentially anhydrous conditions. In contrast to the Vestmannaeyjar lavas, the lavas behind the propagator often contain augite as a phenocryst. It is concluded that the chemical variation observed along the south-eastern propagating rift of Iceland is an effect of primary chemical features and that water plays a significant role on the liquid lines of descent at the front of the propagator. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 75 TC 10 Z9 10 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0024-4937 J9 LITHOS JI Lithos PD JAN PY 1991 VL 26 IS 3-4 BP 253 EP 269 DI 10.1016/0024-4937(91)90032-G PG 17 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA EX223 UT WOS:A1991EX22300004 ER PT B AU IBA, W AF IBA, W BE Birnbaum, LA Collins, GC TI MODELING THE ACQUISITION AND IMPROVEMENT OF MOTOR-SKILLS SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,AI RES BRANCH,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 60 EP 64 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00011 ER PT B AU LANGLEY, P ALLEN, JA AF LANGLEY, P ALLEN, JA BE Birnbaum, LA Collins, GC TI THE ACQUISITION OF HUMAN PLANNING EXPERTISE SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,AI RES BRANCH MS 244-17,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 80 EP 84 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00015 ER PT B AU CHIEN, SA GERVASIO, MT DEJONG, GF AF CHIEN, SA GERVASIO, MT DEJONG, GF BE Birnbaum, LA Collins, GC TI ON BECOMING DECREASINGLY REACTIVE - LEARNING TO DELIBERATE MINIMALLY SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 2 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 288 EP 292 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00055 ER PT B AU KEDAR, ST BRESINA, JL DENT, CL AF KEDAR, ST BRESINA, JL DENT, CL BE Birnbaum, LA Collins, GC TI THE BLIND LEADING THE BLIND - MUTUAL REFINEMENT OF APPROXIMATE THEORIES SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,STERLING FED SYST,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 308 EP 312 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00059 ER PT B AU ALLEN, JA THOMPSON, K AF ALLEN, JA THOMPSON, K BE Birnbaum, LA Collins, GC TI PROBABILISTIC CONCEPT-FORMATION IN RELATIONAL DOMAINS SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,STERLING SOFTWARE,AI RES BRANCH,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 375 EP 379 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00072 ER PT B AU BERENJI, HR AF BERENJI, HR BE Birnbaum, LA Collins, GC TI REFINEMENT OF APPROXIMATE REASONING-BASED CONTROLLERS BY REINFORCEMENT LEARNING SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,STERLING SOFTWARE,ARTIFICIAL INTELLIGENCE RES BRANCH,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 475 EP 479 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00092 ER PT B AU THOMPSON, K LANGLEY, P IBA, W AF THOMPSON, K LANGLEY, P IBA, W BE Birnbaum, LA Collins, GC TI USING BACKGROUND KNOWLEDGE IN CONCEPT-FORMATION SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 NASA,AMES RES CTR,AI RES BRANCH,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 554 EP 558 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00108 ER PT B AU CHIEN, S WHITEHALL, B DIETTERICH, T DOYLE, R FALKENHAINER, B GARRETT, J LU, S AF CHIEN, S WHITEHALL, B DIETTERICH, T DOYLE, R FALKENHAINER, B GARRETT, J LU, S BE Birnbaum, LA Collins, GC TI MACHINE LEARNING IN ENGINEERING AUTOMATION SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 JET PROP LAB,ARTIFICIAL INTELLIGENCE GRP,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 2 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 577 EP 580 PG 4 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00112 ER PT B AU BELYAEV, LV FALCONE, LP AF BELYAEV, LV FALCONE, LP BE Birnbaum, LA Collins, GC TI NOISE-RESISTANT CLASSIFICATION - SUBSYMBOLIC AND HYBRID ARCHITECTURES FOR EVENT CLASSIFICATION IN PLASMA PHYSICS SO MACHINE LEARNING: PROCEEDINGS OF THE EIGHTH INTERNATIONAL WORKSHOP (ML91) LA English DT Proceedings Paper CT 8th International Workshop on Machine Learning (ML91) CY JUN, 1991 CL NORTHWESTERN UNIV, EVANSTON, IL SP NORTHWESTERN UNIV, USN, OFF NAVAL RES HO NORTHWESTERN UNIV C1 JET PROP LAB,ARTIFICIAL INTELLIGENCE GRP,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MORGAN KAUFMANN PUB INC PI SAN MATEO PA 2929 CAMPUS DRIVE, SAN MATEO, CA 94403 BN 1-55860-200-3 PY 1991 BP 581 EP 585 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BA74J UT WOS:A1991BA74J00113 ER PT B AU KONTIZAS, E KONTIZAS, M SEDMAK, G SMAREGLIA, R AF KONTIZAS, E KONTIZAS, M SEDMAK, G SMAREGLIA, R BE HAYNES, R MILNE, D TI SHAPES OF MAGELLANIC CLOUD STAR-CLUSTERS SO MAGELLANIC CLOUDS SE IAU SYMPOSIA LA English DT Proceedings Paper CT 148TH SYMP OF THE INTERNATIONAL ASTRONOMICAL UNION : THE MAGELLANIC CLOUDS CY JUL 09-13, 1990 CL UNIV SYDNEY, WOMENS COLL, SYDNEY, AUSTRALIA SP INT ASTRON UNIV, AUSTR TELESCOPE NATL FAC, ANGLO AUSTR TELESCOPE BOARD, AUSTR NATL UNIV, UNIV SYDNEY, ASTRON SOC AUSTR, DONOVAN ASTRON TRUST, AUSTR GEOG SOC, SO ASTRON MAGAZINE, APPLE COMP AUSTR HO UNIV SYDNEY, WOMENS COLL ID ELLIPTICITIES RP KONTIZAS, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Kontizas, Evangelos/A-1969-2014 NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA DORDRECHT BN 0-7923-1110-8 J9 IAU SYMP PY 1991 VL 148 BP 234 EP 235 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT88T UT WOS:A1991BT88T00060 ER PT B AU PERRY, JW AF PERRY, JW BE MARDER, SR SOHN, JE STUCKY, GD TI NONLINEAR OPTICAL-PROPERTIES OF MOLECULES AND MATERIALS SO MATERIALS FOR NONLINEAR OPTICS: CHEMICAL PERSPECTIVES SE ACS SYMPOSIUM SERIES LA English DT Proceedings Paper CT SYMP AT THE 199TH NATIONAL MEETING OF THE AMERICAN CHEMICAL SOC - MATERIALS FOR NONLINEAR OPTICS : CHEMICAL PERSPECTIVES CY APR 22-27, 1990 CL BOSTON, MA SP AMER CHEM SOC, DIV ORG CHEM, AMER CHEM SOC, DIV INORG CHEM, USAF, OFF SCI RES, PETR RES FUND, AT&T BELL LAB, DUPONT CO, EASTMAN KODAK, USN, OFF NAVAL RES, STRATEG DEF INITIAT ORG, INNOVAT SCI & TECHNOL OFF ID 3RD HARMONIC-GENERATION; SUSCEPTIBILITY DETERMINATION; 3RD-HARMONIC GENERATION; LIQUIDS RP PERRY, JW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 0 TC 10 Z9 10 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA WASHINGTON BN 0-8412-1939-7 J9 ACS SYM SER PY 1991 VL 455 BP 67 EP 88 PG 22 WC Chemistry, Organic; Materials Science, Multidisciplinary; Optics; Physics, Applied; Polymer Science SC Chemistry; Materials Science; Optics; Physics; Polymer Science GA BT21Q UT WOS:A1991BT21Q00004 ER PT B AU BERATAN, DN AF BERATAN, DN BE MARDER, SR SOHN, JE STUCKY, GD TI ELECTRONIC HYPERPOLARIZABILITY AND CHEMICAL-STRUCTURE SO MATERIALS FOR NONLINEAR OPTICS: CHEMICAL PERSPECTIVES SE ACS SYMPOSIUM SERIES LA English DT Proceedings Paper CT SYMP AT THE 199TH NATIONAL MEETING OF THE AMERICAN CHEMICAL SOC - MATERIALS FOR NONLINEAR OPTICS : CHEMICAL PERSPECTIVES CY APR 22-27, 1990 CL BOSTON, MA SP AMER CHEM SOC, DIV ORG CHEM, AMER CHEM SOC, DIV INORG CHEM, USAF, OFF SCI RES, PETR RES FUND, AT&T BELL LAB, DUPONT CO, EASTMAN KODAK, USN, OFF NAVAL RES, STRATEG DEF INITIAT ORG, INNOVAT SCI & TECHNOL OFF ID NONLINEAR OPTICAL-PROPERTIES; CONJUGATED ORGANIC POLYMERS; CHAINS; SUSCEPTIBILITIES RP BERATAN, DN (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Beratan, David/C-5098-2011 NR 0 TC 20 Z9 20 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA WASHINGTON BN 0-8412-1939-7 J9 ACS SYM SER PY 1991 VL 455 BP 89 EP 102 PG 14 WC Chemistry, Organic; Materials Science, Multidisciplinary; Optics; Physics, Applied; Polymer Science SC Chemistry; Materials Science; Optics; Physics; Polymer Science GA BT21Q UT WOS:A1991BT21Q00005 ER PT B AU MARDER, SR TIEMANN, BG PERRY, JW CHENG, LT TAM, W SCHAEFER, WP MARSH, RE AF MARDER, SR TIEMANN, BG PERRY, JW CHENG, LT TAM, W SCHAEFER, WP MARSH, RE BE MARDER, SR SOHN, JE STUCKY, GD TI ORGANIC AND ORGANOMETALLIC COMPOUNDS - 2ND-ORDER MOLECULAR AND MACROSCOPIC OPTICAL NONLINEARITIES SO MATERIALS FOR NONLINEAR OPTICS: CHEMICAL PERSPECTIVES SE ACS SYMPOSIUM SERIES LA English DT Proceedings Paper CT SYMP AT THE 199TH NATIONAL MEETING OF THE AMERICAN CHEMICAL SOC - MATERIALS FOR NONLINEAR OPTICS : CHEMICAL PERSPECTIVES CY APR 22-27, 1990 CL BOSTON, MA SP AMER CHEM SOC, DIV ORG CHEM, AMER CHEM SOC, DIV INORG CHEM, USAF, OFF SCI RES, PETR RES FUND, AT&T BELL LAB, DUPONT CO, EASTMAN KODAK, USN, OFF NAVAL RES, STRATEG DEF INITIAT ORG, INNOVAT SCI & TECHNOL OFF ID 2ND HARMONIC-GENERATION; 2ND-HARMONIC GENERATION; INCLUSION COMPLEXES; DIPOLE-MOMENT; HYPERPOLARIZABILITIES; CRYSTALS RP MARDER, SR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Perry, Joseph/B-7191-2011 OI Perry, Joseph/0000-0003-1101-7337 NR 0 TC 16 Z9 16 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA WASHINGTON BN 0-8412-1939-7 J9 ACS SYM SER PY 1991 VL 455 BP 187 EP 199 PG 13 WC Chemistry, Organic; Materials Science, Multidisciplinary; Optics; Physics, Applied; Polymer Science SC Chemistry; Materials Science; Optics; Physics; Polymer Science GA BT21Q UT WOS:A1991BT21Q00011 ER PT J AU KIM, CJ DEGUIRE, MR ALLEN, CJ SAYIR, A AF KIM, CJ DEGUIRE, MR ALLEN, CJ SAYIR, A TI GROWTH AND CHARACTERIZATION OF BI-SR-CA-CU-O SUPERCONDUCTING FIBERS SO MATERIALS RESEARCH BULLETIN LA English DT Article DE BISMUTH; CUPRATES; FIBER; SUPERCONDUCTORS ID HEATED PEDESTAL GROWTH; CRYSTALS; SYSTEM AB With the laser-heated floating zone method, fibers of nominal overall composition Bi2Sr2CaCu2O8+/-z and Bi2Sr2Ca2Cu3O10+/-z have been grown. Fibers of uniform diameter up to approximately 1 cm long have been produced. The influence of the growth rates and feed rod compositions on the microstructure of grown fibers were determined with XRD, SEM, EDS, and resistive T(c) measurements. At 5 mm/h growth rate, compositionally homogeneous material can be grown from the 2212 composition over a length of several hundred mu-m. Fibers grown at higher rates consist predominantly of Bi2+x(Sr,Ca)(2-x)CuO6+/-z (the 25 angstrom phase) with smaller amounts of Bi2(Sr,Ca)3Cu2O8+/-z (the 31 angstrom phase) and (Sr,Ca)CuO2 phases. These multiphase fibers show a resistive superconducting transition at 80K. After annealing at 800-degrees-C for 12 hrs in air, the proportion of the 31 angstrom phase is increased, the normal state resistivity is decreased, and the T(c) rises to 90K. C1 CASE WESTERN RESERVE UNIV,DEPT PHYS,CLEVELAND,OH 44106. NASA,LEWIS RES CTR,DIV MAT,CLEVELAND,OH 44135. RP KIM, CJ (reprint author), CASE WESTERN RESERVE UNIV,DEPT MAT SCI & ENGN,CLEVELAND,OH 44106, USA. NR 16 TC 8 Z9 8 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0025-5408 J9 MATER RES BULL JI Mater. Res. Bull. PD JAN PY 1991 VL 26 IS 1 BP 29 EP 39 DI 10.1016/0025-5408(91)90035-K PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA EU985 UT WOS:A1991EU98500004 ER PT J AU WU, MLC CHANG, LSA SMITH, W AF WU, MLC CHANG, LSA SMITH, W TI THE IMPACT OF GEOPHYSICAL PARAMETERS ON LONGWAVE RADIATION BUDGET AT THE TOP AND BASE OF THE ATMOSPHERE SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID SATELLITE; SURFACE; SOUNDINGS AB The effect of clouds on longwave radiation budget at the top and base of the atmosphere is studied by using the HIRS2/MSU-retrieved temperature and humidity fields, and cloud fields and the International Satellite Cloud Climatology Project-produced fields. Detailed studies are carried out at four selected sites: one at Equatorial Eastern Pacific (ITCZ) area, one at Libyan Desert (Libya), one at Ottawa, Montreal (Ottawa), and one at central Europe (Europe). The monthly mean differences in outgoing longwave radiation (OLR) (the ISCCP-based OLR minus the HIRS2-based OLR), ranging from - 2.8 Wm-2 at ITCZ to - 15.4 Wm-2 at Ottawa, are less than the monthly mean differences in surface downward flux, ranging from - 2.7 Wm-2 at Libya to 40.6 Wm-2 at the ITCZ. The large differences in surface downward flux are mainly due to large differences in cloud amount and moisture in the low levels of the atmosphere. Monthly mean OLR and surface downward flux can be derived either (1) from instantaneous temperature, humidity, and cloud fields over a month period or (2) from monthly mean temperature, humidity, and cloud fields. The monthly mean OLR and surface downward flux derived from the first approach is compared with the second. The differences in OLR are small, ranging from - 0.05 Wm-2 to 6.2 Wm-2, and the differences in surface downward flux is also small, ranging from 0.4 Wm-2 to 6.4 Wm-2. C1 CENT FED SERV STAFF,ROCKVILLE,MD 20852. RP WU, MLC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PY 1991 VL 46 IS 1-2 BP 29 EP 40 DI 10.1007/BF01026621 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FX536 UT WOS:A1991FX53600003 ER PT J AU KOCH, SE KOCIN, PJ AF KOCH, SE KOCIN, PJ TI FRONTAL CONTRACTION PROCESSES LEADING TO THE FORMATION OF AN INTENSE NARROW RAINBAND SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID COLD FRONTS; MICROSCALE STRUCTURE; PRECIPITATION; MESOSCALE; LEVEL; FRONTOGENESIS; MODELS; SCALE; ENVIRONMENTS; ORGANIZATION AB Processes which played an important role in the sudden development of an intense narrow cold frontal rainband (NCFR) along the leading edge of a wintertime anafront are investigated. Quantitative analysis of the Regional Analysis and Forecast System (RAFS) initialization and Nested Grid Model (NGM) forecast fields, satellite-derived water vapor and ozone measurements, and conventional meteorological data are employed in this study. The NCFR developed upon merger of an arctic front with a nearly stationary cold front over the Appalachian mountains. Rapid intensification of an ageostrophic momentum surge associated with the formation of a sub-synoptic surface pressure ridge immediately behind the arctic front played a dominant role in forcing explosive frontogenesis during frontal merger. A deep tropopause fold and related mid-tropospheric subsidence feature within the entrance region of an upper-level jet crossed the mountains at the time of NCFR formation. Synthesis of the surface, NGM, and satellite data suggests that this subsidence resulted in the development of the sub-synoptic high pressure system, whose leading edge was marked by a 5 mb pressure jump. Consequential amplification and scale contraction of the cross-front pressure gradient indicates that the scale of the merged frontal system contracted just prior to NCFR development. As precipitation developed, the pressure jump took on a microscale character and increased to 8 mb amplitude. The subsequent intensity of this frontal rainband is explained by the interaction between vertical shear associated with a strong, pre-frontal, low-level jet and the gravity current-like structure at the leading edge of the merged cold front. C1 NOAA,NATL WEATHER SERV,NATL METEOROL CTR,WASHINGTON,DC 20233. RP KOCH, SE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHER LAB,CODE 912,GREENBELT,MD 20771, USA. NR 55 TC 21 Z9 21 U1 0 U2 4 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PY 1991 VL 46 IS 3-4 BP 123 EP 154 DI 10.1007/BF01027339 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA GP903 UT WOS:A1991GP90300002 ER PT J AU BRILL, KF UCCELLINI, LW MANOBIANCO, J KOCIN, PJ HOMAN, JH AF BRILL, KF UCCELLINI, LW MANOBIANCO, J KOCIN, PJ HOMAN, JH TI THE USE OF SUCCESSIVE DYNAMIC INITIALIZATION BY NUDGING TO SIMULATE CYCLOGENESIS DURING GALE IOP-1 SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; MODELS AB Synoptic/diagnostic case studies have increasingly come to rely on numerical simulations started from some initial state after which the model generated fields receive no further information from observed data. The purpose of this paper is to demonstrate the use of a dynamic data assimilation technique based on nudging to create a dynamically consistent, high-resolution four-dimensional data set that can be used for synoptic diagnostic studies. The nudging technique is applied in the Goddard Mesoscale Atmospheric Simulation System (GMASS) using the 3-h radiosonde data collected during GALE IOP 1. A unique aspect of this application is nudging toward data analyses for which the areal coverage shifts with time. One of the two nudging simulations assimilates surface pressure in addition to the temperature, mixing ratio, and wind components. The nudging values are determined by linear interpolation between 3-h observation times. Assuming a linear variation of the assimilated value in time leads to estimates of the nudging coefficients which take into account the accuracy of the observations. Both nudging simulations are more accurate in terms of S 1 and root-mean-square error (RMSE) scores than a control simulation without successive initialization. The nudging simulation with surface pressure is more accurate than the nudging simulation without surface pressure assimilation for this case. The simulation with surface pressure nudging captures the surface cyclogenesis and the associated strong rise-fall couplet in the 500hPa height field. It also exhibits the strongest ageostrophic flow and exit region vertical circulation associated with a jet streak on the western side of the intensifying upper-level trough. The data sets made possible by the dynamic assimilation/simulation cycles are dynamically consistent, have high spatial and temporal resolution and are ideally suited for diagnostic studies. Examples presented include the evolution of the ageostrophic flow associated with the exit region of an upper-level jet propagating toward the base of an intensifying trough with increasing cyclonic curvature of the flow. The nudging simulation with surface pressure provides the resolution and accuracy required to depict the rapid transformation (within a 12-h period) of the exit region ageostrophic flow from predominantly cross contour to along contour as the jet streak approaches the base of the trough. C1 GEN SCI CORP,LAUREL,MD. RES & DATA SYST,GREENBELT,MD. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. NR 30 TC 13 Z9 13 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PY 1991 VL 45 IS 1-2 BP 15 EP 40 DI 10.1007/BF01027473 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EW493 UT WOS:A1991EW49300002 ER PT J AU MANOBIANCO, J UCCELLINI, LW BRILL, KF KOCIN, PJ AF MANOBIANCO, J UCCELLINI, LW BRILL, KF KOCIN, PJ TI CONTRASTING THE IMPACT OF DYNAMIC DATA ASSIMILATION ON THE NUMERICAL SIMULATIONS OF CYCLOGENESIS DURING GALEIOP-10 AND IOP-1 SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID CUMULUS CONVECTION; MODELS; PREDICTION; CYCLONE; OCEAN; HEAT AB The nudging assimilation scheme described in the companion paper by Brill et al. is applied to study oceanic cyclogenesis during GALE IOP 10 on 27-28 February 1986. A 36-h control simulation statically initialized from 0000 UTC 27 February 1986 data moves the cyclone too far north and east in the 12-h period of most rapid deepening limiting the usefulness of the simulation for diagnostic study. The use of nudging to dynamically assimilate special 3-h and routine 12-h rawindsonde and dropsonde data into the model during the entire 36-h forecast period failed to deepen the cyclone as it moved northeast off the Atlantic seaboard beyond the area covered 3-h by sounding data. Subjectively analyzed mean sea-level pressures (MSLP) were included in the data base to allow the model to nudge toward 3-h surface pressure analyses extended to cover the region of cyclogenesis over the ocean. The assimilation of 3-h surface data over the ocean is insufficient to produce a realistic simulation of cyclogenesis. This result motivated the use of the nudging technique to assimilate surface pressure and upper air data over land during the 12-h pre-cyclogenetic period (i.e. dynamic initialization) and compare the subsequent 24-h simulation with one initialized statically at the same synoptic time. Dynamic initialization produced the best simulation of the oceanic cyclone based upon the standard statistical scores and positions of the MSLP minima. This simulation is used to diagnose differences between cyclogenesis during GALE IOP 1 and IOP 10. Isentropic analyses and vertical cross sections are derived from the model simulations and are used to contrast the strength of the upper tropospheric forcing and the low-level static stability associated with each case. The results of the diagnostic analyses reveal that stronger surface response (based upon MSLP minima) to weaker upper-level forcing during GALE IOP 10 (compared with GALE IOP 1) was associated with differences in the lower tropospheric static stability and thermal advection patterns and their interaction with upper tropospheric features. C1 RES & DATA SYST,GREENBELT,MD 20771. GEN SCI CORP,LAUREL,MD. RP MANOBIANCO, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 973,GREENBELT,MD 20771, USA. NR 33 TC 10 Z9 10 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PY 1991 VL 45 IS 1-2 BP 41 EP 63 DI 10.1007/BF01027474 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EW493 UT WOS:A1991EW49300003 ER PT J AU CHARLOCK, TP ROSE, FG AF CHARLOCK, TP ROSE, FG TI FLUCTUATIONS OF HIGH CLOUDS AND 500-MB GEOPOTENTIAL HEIGHTS IN BAROCLINIC WAVE-GUIDES SO MONTHLY WEATHER REVIEW LA English DT Article ID GENERAL-CIRCULATION MODEL; HEMISPHERE WINTERTIME CIRCULATION; EXTRATROPICAL NORTHERN HEMISPHERE; SHORT-TIME SCALES; VERTICAL STRUCTURE; SATELLITE DATA; STATISTICS; INTERMEDIATE; RADIATION; LONG AB A time filter that passes waves with periods in the 2.5-6.0 day band is applied to a six-winter record of the Nimbus-7 THIR/TOMS high cloudiness and the NMC 500-mb geopotential height in the northern extratropics. The strongest correlations between fluctuations in geopotential and high cloudiness are found in the baroclinic waveguides, where the fields of both geopotential and high cloudiness exhibit large variabilities. Over many grid points in the waveguides, positive anomalies in high cloud areas are found to be approximately one-third of a wavelength to the east of negative anomalies in 500-mb heights (band-pass troughs), and negative anomalies in high cloud areas are found to be approximately one-sixth of a wavelength to the west. A map of the standardized anomalies in the cloud area associated with height fluctuations above the mean forms a simple negative of the map of the cloud anomalies associated with height fluctuations below the mean. The analysis presented here suggests that the high cloud structures of baroclinic waves are less spatially coherent than the internal geopotential height structures. Over the North Pacific, small-scale (latitudinal wavenumber 13-18) fluctuations in geopotential appear to play a greater role in forcing high cloudiness than do medium-scale (latitudinal wavenumber 7-12) fluctuations in geopotential. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA. RP CHARLOCK, TP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23665, USA. OI Rose, Fred G/0000-0003-0769-0772 NR 27 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JAN PY 1991 VL 119 IS 1 BP 73 EP 83 DI 10.1175/1520-0493(1991)119<0073:FOHCAM>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FA682 UT WOS:A1991FA68200005 ER PT J AU BATES, JR AF BATES, JR TI NON-INTERPOLATING SEMI-LAGRANGIAN ADVECTION SCHEMES WITH MINIMIZED DISSIPATION AND DISPERSION ERRORS - COMMENTS SO MONTHLY WEATHER REVIEW LA English DT Letter RP BATES, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 911,BLDG 22,GREENBELT,MD 20771, USA. NR 5 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JAN PY 1991 VL 119 IS 1 BP 230 EP 231 DI 10.1175/1520-0493(1991)119<0230:COSUAS>2.0.CO;2 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FA682 UT WOS:A1991FA68200018 ER PT J AU EBERHARDT, SP DAUD, T KERNS, DA BROWN, TX THAKOOR, AP AF EBERHARDT, SP DAUD, T KERNS, DA BROWN, TX THAKOOR, AP TI COMPETITIVE NEURAL ARCHITECTURE FOR HARDWARE SOLUTION TO THE ASSIGNMENT PROBLEM SO NEURAL NETWORKS LA English DT Article DE ASSIGNMENT PROBLEM; NEURAL NETWORK; COMPETITION; NEUROPROCESSOR; HYSTERESIS; ANNEALING; VLSI ID OPTIMIZATION; NEURONS; DESIGN AB A neural network architecture for competitive assignment is presented, with details of a very large scale integration (VLSI) design and characterization of critical circuits fabricated in complementary metal-oxide semiconductor (CMOS). The assignment problem requires that elements of two sets (e.g., resources and consumers) be associated with each other such as to minimize the total cost of the associations. Unlike previous neural implementations, association costs are applied locally to processing units (PUs, i.e., neurons), reducing connectivity to VLSI-compatible O(number of PUs). Also, each element in either set may be independently programmed to associate with one, several, or a range of elements of the other set. A novel method of "hysteretic annealing," effected by gradually increasing positive feedback within each PU, was developed and compared in simulations to mean-field annealing implemented by increasing PU gain over time. The simulations (to size 64 x 64) consistently found optimal or near-optimal solutions, with settling times of about 150 microseconds, except for a few variable-gain annealing trials that exhibited oscillation. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. NR 31 TC 29 Z9 30 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0893-6080 J9 NEURAL NETWORKS JI Neural Netw. PY 1991 VL 4 IS 4 BP 431 EP 442 DI 10.1016/0893-6080(91)90039-8 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA GA146 UT WOS:A1991GA14600001 ER PT J AU SHEPHERD, KP HUBBARD, HH AF SHEPHERD, KP HUBBARD, HH TI PHYSICAL CHARACTERISTICS AND PERCEPTION OF LOW-FREQUENCY NOISE FROM WIND TURBINES SO NOISE CONTROL ENGINEERING JOURNAL LA English DT Article AB Available literature relating to the generation, propagation and perception of low frequency noise from large wind turbines is briefly reviewed. Example data are included for several machines along with their geometric and operating characteristics. Case history data are presented and compared with criteria proposed for the perception of low frequency noise and noise induced house vibrations due to wind turbine operations. RP SHEPHERD, KP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 6 Z9 6 U1 0 U2 3 PU INST NOISE CONTROL ENG PI POUGHKEEPSIE PA PO BOX 3206 ARLINGTON BRANCH, POUGHKEEPSIE, NY 12603 SN 0736-2501 J9 NOISE CONTROL ENG JI Noise Control Eng. J. PD JAN-FEB PY 1991 VL 36 IS 1 BP 5 EP 15 DI 10.3397/1.2827777 PG 11 WC Acoustics; Engineering, Multidisciplinary SC Acoustics; Engineering GA FF272 UT WOS:A1991FF27200002 ER PT B AU KAZANAS, D AF KAZANAS, D BE BUCHLER, JR DETWEILER, SL IPSER, JR TI ASTROPHYSICAL ASPECTS OF WEYL GRAVITY SO NONLINEAR PROBLEMS IN RELATIVITY AND COSMOLOGY SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Proceedings Paper CT 6TH FLORIDA WORKSHOP IN NONLINEAR ASTRONOMY : NONLINEAR PROBLEMS IN RELATIVITY AND COSMOLOGY CY OCT 11-13, 1990 CL UNIV FLORIDA, GAINESVILLE, FL SP UNIV FLORIDA, COLL LIBERAL ARTS & SCI, UNIV FLORIDA, ASTRON DEPT, UNIV FLORIDA, PHYS DEPT, UNIV FLORIDA, DIV SPONSORED RES HO UNIV FLORIDA ID RENORMALIZATION; GALAXIES; UNIVERSE RP KAZANAS, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU NEW YORK ACAD SCIENCES PI NEW YORK PA NEW YORK BN 0-89766-668-2 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 1991 VL 631 BP 212 EP 224 PG 13 WC Astronomy & Astrophysics; Mathematics, Applied SC Astronomy & Astrophysics; Mathematics GA BU24V UT WOS:A1991BU24V00020 ER PT J AU BENNETT, GL AF BENNETT, GL TI THE SAFETY REVIEW AND APPROVAL PROCESS FOR SPACE NUCLEAR-POWER SOURCES SO NUCLEAR SAFETY LA English DT Article AB Over the past 30 yr, the U.S. Government has evolved a process for the safety review and launch approval of nuclear power sources (NPSs) proposed for launch into space. This process, which involves a number of governmental agencies, ensures that the various postulated accident scenarios are considered, that the responses of the NPSs to the accident environments are assessed, and that appropriate elements of the Federal Government are involved in the launch approval. This process has worked very well in the successful launches of 37 radioisotope thermoelectric generators and 1 reactor by the United States since 1961. Particular attention will be focused on the recent launch of the Galileo spacecraft. RP BENNETT, GL (reprint author), NASA,DIV PROPULS POWER & ENERGY,OFF AERONAUT EXPLORAT & TECHNOL,WASHINGTON,DC 20546, USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPT OF DOCUMENTS, WASHINGTON, DC 20402-9325 SN 0029-5604 J9 NUCL SAFETY JI Nucl. Saf. PD JAN-MAR PY 1991 VL 32 IS 1 BP 1 EP 18 PG 18 WC Environmental Sciences; Nuclear Science & Technology SC Environmental Sciences & Ecology; Nuclear Science & Technology GA FX724 UT WOS:A1991FX72400001 ER PT J AU HESSE, A ACHARYA, BS HEINBACH, U HEINRICH, W HENKEL, M LUZIETTI, B KOCH, C SIMON, M BALASUBRAHMANYAN, VK BARBIER, LM CHRISTIAN, ER ESPOSITO, JA ORMES, JF STREITMATTER, RE AF HESSE, A ACHARYA, BS HEINBACH, U HEINRICH, W HENKEL, M LUZIETTI, B KOCH, C SIMON, M BALASUBRAHMANYAN, VK BARBIER, LM CHRISTIAN, ER ESPOSITO, JA ORMES, JF STREITMATTER, RE TI AN ISOTOPE EXPERIMENT USING CHERENKOV RANGE TECHNIQUE SO NUCLEAR TRACKS AND RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 15TH INTERNATIONAL CONF ON PARTICLE TRACKS IN SOLIDS CY SEP 03-07, 1990 CL MARBURG, GERMANY SP INT NUCL TRACK SOC DE COSMIC PARTICLE RADIATION; BALLOON EXPERIMENT; ISOTOPE ANALYSIS; CHERENKOV-RANGE TECHNIQUE ID DRIFT CHAMBER TELESCOPE; ION TRACK DETECTION AB The ALICE balloon experiment utilizes the Cherenkov-range technique to determine the isotopic composition of the cosmic radiation in the elemental range magnesium through iron. The instrument operates in the energy range 350 MeV/nucleon to 800 MeV/nucleon. Particle charge and energy are determined from scintillation and Cherenkov radiation emissions within light diffusion chambers. Trajectories of incoming particles are determined by means of large area gas drift chambers. The stopping range of the particles is measured in a cellulose nitrate range stack. This paper reports details of the experimental technique and results of the balloon flight. C1 TATA INST,BOMBAY,INDIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HESSE, A (reprint author), UNIV SIEGEN,DEPT PHYS,ADOLF REICHWEIN STR,W-5900 SIEGEN,PEOPLES R CHINA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 5 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0735-245X J9 NUCL TRACKS RAD MEAS PY 1991 VL 19 IS 1-4 BP 689 EP 694 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA GP190 UT WOS:A1991GP19000163 ER PT J AU BANKS, HT WADE, JG AF BANKS, HT WADE, JG TI WEAK-TAU APPROXIMATIONS FOR DISTRIBUTED PARAMETER-SYSTEMS IN INVERSE PROBLEMS SO NUMERICAL FUNCTIONAL ANALYSIS AND OPTIMIZATION LA English DT Article ID MODELS AB A theoretical framework for proposed ''weak Tau'' type of approximation schemes is considered in the context of least-squares parameter estimation problems for partial differential equations. A convergence theory which includes parameter estimate convergence and method stability is developed. Numerical results demonstrating the possible advantages of these ideas are also presented. C1 UNIV SO CALIF,CTR APPL MATH SCI,LOS ANGELES,CA 90089. NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. NR 24 TC 3 Z9 3 U1 0 U2 0 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 SN 0163-0563 J9 NUMER FUNC ANAL OPT JI Numer. Funct. Anal. Optim. PY 1991 VL 12 IS 1-2 BP 1 EP 31 DI 10.1080/01630569108816418 PG 31 WC Mathematics, Applied SC Mathematics GA GH782 UT WOS:A1991GH78200001 ER PT J AU FREUND, RW NACHTIGAL, NM AF FREUND, RW NACHTIGAL, NM TI QMR - A QUASI-MINIMAL RESIDUAL METHOD FOR NON-HERMITIAN LINEAR-SYSTEMS SO NUMERISCHE MATHEMATIK LA English DT Article ID ALGORITHM; MATRIX AB The biconjugate gradient (BCG) method is the "natural" generalization of the classical conjugate gradient algorithm for Hermitian positive definite matrices to general non-Hermitian linear systems. Unfortunately, the original BCG algorithm is susceptible to possible breakdowns and numerical instabilities. In this paper, we present a novel BCG-like approach, the quasi-minimal residual (QMR) method, which overcomes the problems of BCG. An implementation of QMR based on a look-ahead version of the nonsymmetric Lanczos algorithm is proposed. It is shown how BCG iterates can be recovered stably from the QMR process. Some further properties of the QMR approach are given and an error bound is presented. Finally, numerical experiments are reported. C1 UNIV WURZBURG,INST ANGEW MATH & STAT,W-8700 WURZBURG,GERMANY. MIT,DEPT MATH,CAMBRIDGE,MA 02139. RP FREUND, RW (reprint author), NASA,AMES RES CTR,RIACS,MAIL STOP ELLIS ST,MOFFETT FIELD,CA 94035, USA. NR 24 TC 567 Z9 576 U1 2 U2 10 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0029-599X J9 NUMER MATH JI Numer. Math. PY 1991 VL 60 IS 3 BP 315 EP 339 DI 10.1007/BF01385726 PG 25 WC Mathematics, Applied SC Mathematics GA GV412 UT WOS:A1991GV41200002 ER PT J AU GARCIAMENDEZ, G MAASS, JM MATSON, PA VITOUSEK, PM AF GARCIAMENDEZ, G MAASS, JM MATSON, PA VITOUSEK, PM TI NITROGEN TRANSFORMATIONS AND NITROUS-OXIDE FLUX IN A TROPICAL DECIDUOUS FOREST IN MEXICO SO OECOLOGIA LA English DT Article DE TROPICAL DECIDUOUS FOREST; TROPICAL PASTURE; LAND CLEARING; NITROGEN LOSS; NITROUS OXIDE ID SOILS; JALISCO; SAVANNA; TRENDS; SEASON; N2O AB Emissions of nitrous oxide and soil nitrogen pools and transformations were measured over an annual cycle in two forests and one pasture in tropical deciduous forest near Chamela, Mexico. Nitrous oxide flux was moderately high (0.5-2.5 ng cm-2 h-1) during the wet season and low (< 0.3 ng cm-2 h-1) during the dry season. Annual emissions of nitrogen as nitrous oxide were calculated to be 0.5-0.7 kg ha-1 y-1, with no substantial difference between the forests and pasture. Wetting of dry soil caused a large but short-lived pulse of N2O flux that accounted for < 2% of annual flux. Variation in soil water through the season was the primary controlling factor for pool sizes of ammonium and nitrate, nitrogen transformations, and N2O flux. C1 NASA,AMES RES CTR,DIV EARTH SYST SCI,MOFFETT FIELD,CA 94305. STANFORD UNIV,DEPT BIOL SCI,STANFORD,CA 94305. RP GARCIAMENDEZ, G (reprint author), NATL AUTONOMOUS UNIV MEXICO,CTR ECOL,APARTADO POSTAL 70-275,MEXICO CITY 04510,DF,MEXICO. NR 26 TC 67 Z9 68 U1 0 U2 11 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0029-8549 J9 OECOLOGIA JI Oecologia PY 1991 VL 88 IS 3 BP 362 EP 366 DI 10.1007/BF00317579 PG 5 WC Ecology SC Environmental Sciences & Ecology GA GP207 UT WOS:A1991GP20700009 PM 28313797 ER PT J AU MCDERMID, IS HANER, DA KLEIMAN, MM WALSH, TD WHITE, ML AF MCDERMID, IS HANER, DA KLEIMAN, MM WALSH, TD WHITE, ML TI DIFFERENTIAL ABSORPTION LIDAR SYSTEMS FOR TROPOSPHERIC AND STRATOSPHERIC OZONE MEASUREMENTS SO OPTICAL ENGINEERING LA English DT Article DE LIDAR; DIFFERENTIAL ABSORPTION LIDAR; OZONE LIDAR AB A lidar facility has been established at the Jet Propulsion Laboratory-Table Mountain Facility located at an altitude of 2300 m in the San Gabriel Mountains in Southern California. This facility is using the technique of differential absorption lidar to measure atmospheric ozone concentration profiles. Two separate systems are needed to obtain the profile from the ground up to an altitude of 45 to 50 km. A Nd:YAG-based system is described for measurements from the ground up to 15 to 20 km altitude, and an excimer-laser-based system for measurements from 15 km to 45 to 50 km altitude. The systems were designed to make high-precision, long-term measurements to aid in detection of changes in the atmospheric ozone abundance through participation in Network of Detection of Stratospheric Change. RP MCDERMID, IS (reprint author), CALTECH,JET PROP LAB,TABLE MT FACIL,WRIGHTWOOD,CA 92397, USA. NR 19 TC 23 Z9 24 U1 1 U2 5 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1991 VL 30 IS 1 BP 22 EP 30 DI 10.1117/12.55768 PG 9 WC Optics SC Optics GA EU559 UT WOS:A1991EU55900004 ER PT J AU MCGEE, TJ WHITEMAN, D FERRARE, R BUTLER, JJ BURRIS, JF AF MCGEE, TJ WHITEMAN, D FERRARE, R BUTLER, JJ BURRIS, JF TI STROZ LITE - STRATOSPHERIC OZONE LIDAR TRAILER EXPERIMENT SO OPTICAL ENGINEERING LA English DT Article DE LIDAR; OZONE LIDAR; DIFFERENTIAL ABSORPTION LIDAR ID LASER-RADAR; ATMOSPHERE; LAYER AB As a part of the international Network for the Detection of Stratospheric Change, Goddard Space Flight Center has developed a mobile differential absorption lidar capable of making precise and accurate measurements in the stratosphere between 20 and 45 km. We present in this paper a description of the instrument, a discussion of the data analysis, and some results from an intercomparison held at JPL's Table Mountain Observatory in California during October and November 1988. C1 NASA,GODDARD SPACE FLIGHT CTR,OCEANS LAB,GREENBELT,MD 20771. STX CORP,LANHAM,MD 20706. RP MCGEE, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 610,GREENBELT,MD 20771, USA. RI McGee, Thomas/G-4951-2013; Butler, James/D-4188-2013 NR 29 TC 42 Z9 42 U1 0 U2 2 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1991 VL 30 IS 1 BP 31 EP 39 DI 10.1117/12.55771 PG 9 WC Optics SC Optics GA EU559 UT WOS:A1991EU55900005 ER PT J AU GRANT, WB AF GRANT, WB TI DIFFERENTIAL ABSORPTION AND RAMAN LIDAR FOR WATER-VAPOR PROFILE MEASUREMENTS - A REVIEW SO OPTICAL ENGINEERING LA English DT Review DE RAMAN LIDAR; DIFFERENTIAL ABSORPTION LIDAR; WATER VAPOR; RAMAN SCATTERING; DYE LASER; ALEXANDRITE LASER; TIAL2O3 LASER ID 720-NM WAVELENGTH REGION; DIAL MEASUREMENTS; BROADENING COEFFICIENTS; ATMOSPHERIC EXTINCTION; TEMPERATURE PROFILES; REMOTE MEASUREMENT; BOUNDARY-LAYER; CROSS-SECTIONS; DYE-LASER; SCATTERING AB Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. During this period, there have been considerable advances in laser and lidar technology, as well as in the understanding of the factors required to optimize both lidar techniques for water vapor measurements. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar system. RP GRANT, WB (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MS 401A,HAMPTON,VA 23665, USA. RI Grant, William/B-8311-2009 OI Grant, William/0000-0002-1439-3285 NR 132 TC 44 Z9 44 U1 2 U2 10 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1991 VL 30 IS 1 BP 40 EP 48 DI 10.1117/12.55772 PG 9 WC Optics SC Optics GA EU559 UT WOS:A1991EU55900006 ER PT J AU BUFTON, JL GARVIN, JB CAVANAUGH, JF RAMOSIZQUIERDO, L CLEM, TD KRABILL, WB AF BUFTON, JL GARVIN, JB CAVANAUGH, JF RAMOSIZQUIERDO, L CLEM, TD KRABILL, WB TI AIRBORNE LIDAR FOR PROFILING OF SURFACE-TOPOGRAPHY SO OPTICAL ENGINEERING LA English DT Article DE LIDAR; LASER ALTIMETRY; LASER RANGING; AIRBORNE LIDAR ID LASER AB A lidar system is described that measures laser pulse time-of-flight and the distortion of the pulse waveform for reflection from Earth surface terrain features. This instrument system is mounted on a high-altitude aircraft platform and operated in a repetitively pulsed mode for measurements of surface elevation profiles. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology. Aircraft position in three dimensions is measured to submeter accuracy by use of differential Global Positioning System receivers. Instrument construction and performance are detailed. C1 NASA,OBSERV SCI BRANCH,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. RP BUFTON, JL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771, USA. NR 13 TC 29 Z9 30 U1 1 U2 5 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1991 VL 30 IS 1 BP 72 EP 78 DI 10.1117/12.55770 PG 7 WC Optics SC Optics GA EU559 UT WOS:A1991EU55900010 ER PT J AU COUCH, RH ROWLAND, CW ELLIS, KS BLYTHE, MP REGAN, CP KOCH, MR ANTILL, CW KITCHEN, WL COX, JW DELORME, JF CROCKETT, SK REMUS, RW CASAS, JC HUNT, WH AF COUCH, RH ROWLAND, CW ELLIS, KS BLYTHE, MP REGAN, CP KOCH, MR ANTILL, CW KITCHEN, WL COX, JW DELORME, JF CROCKETT, SK REMUS, RW CASAS, JC HUNT, WH TI LIDAR IN-SPACE TECHNOLOGY EXPERIMENT (LITE) - NASAS 1ST IN-SPACE LIDAR SYSTEM FOR ATMOSPHERIC RESEARCH SO OPTICAL ENGINEERING LA English DT Article DE SPACE LIDAR; SPACE SHUTTLE LIDAR; LIDAR IN-SPACE TECHNOLOGY EXPERIMENT AB The Lidar In-Space Technology Experiment (LITE) is being developed by NASA/Langley Research Center for flight on the Space Shuttle. The system will detect stratospheric and tropospheric aerosols, probe the planetary boundary layer, measure cloud top heights, and measure atmospheric temperature and density in the range of 10 to 40 km. The system consists of a nominal 1 m diameter telescope receiver, a three-color neodymium: YAG laser transmitter, and the system electronics. The instrument makes extensive use of Space Shuttle resources for electrical power, thermal control, and command and data handling. The instrument will fly on the Space Shuttle in mid-1993. This paper presents the engineering aspects of the design, fabrication, integration, and operation of the instrument. A companion paper by members of the LITE Science Steering Group that details the science aspects of LITE is in preparation and will be published at a later time. C1 SPACETEC VENTURES,HAMPTON,VA 23666. WYLE LABS,HAMPTON,VA 23666. RP COUCH, RH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 12 Z9 14 U1 0 U2 2 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1991 VL 30 IS 1 BP 88 EP 95 DI 10.1117/12.55775 PG 8 WC Optics SC Optics GA EU559 UT WOS:A1991EU55900012 ER PT J AU MCKAY, CP HARTMAN, H AF MCKAY, CP HARTMAN, H TI HYDROGEN-PEROXIDE AND THE EVOLUTION OF OXYGENIC PHOTOSYNTHESIS SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article ID SUPEROXIDE-DISMUTASE; MARS; ATMOSPHERE; FIXATION; NITROGEN; IRON; LIFE AB The early atmosphere of the Earth is considered to have been reducing (H-2 rich) or neutral (CO2-N2). The present atmosphere by contrast is highly oxidizing (20% O2). The source of this oxygen is generally agreed to have been oxygenic photosynthesis, whereby organisms use water as the electron donor in the production of organic matter, liberating oxygen into the atmosphere. A major question in the evolution of life is how oxygenic photosynthesis could have evolved under anoxic conditions - and also when this capability evolved. It seems unlikely that water would be employed as the electron donor in anoxic environments that were rich in reducing agents such as ferrous or sulfide ions which could play that role. The abiotic production of atmospheric oxidants could have provided a mechanism by which locally oxidizing conditions were sustained within spatially confined habitats thus removing the available reductants and forcing photosynthetic organisms to utilize water as the electron donor. We suggest that atmospheric H2O2 played the key role in inducing oxygenic photosynthesis because as peroxide increased in a local environment, organisms would not only be faced with a loss of reductant, but they would also be pressed to develop the biochemical apparatus (e.g., catalase) that would ultimately be needed to protect against the products of oxygenic photosynthesis. This scenario allows for the early evolution of oxygenic photosynthesis while global conditions were still anaerobic. C1 UNIV CALIF BERKELEY,DEPT SOIL SCI,BERKELEY,CA 94720. RP MCKAY, CP (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. NR 29 TC 37 Z9 38 U1 0 U2 14 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PY 1991 VL 21 IS 3 BP 157 EP 163 DI 10.1007/BF01809444 PG 7 WC Biology SC Life Sciences & Biomedicine - Other Topics GA GW818 UT WOS:A1991GW81800005 PM 11537538 ER PT J AU LORENCEAU, J SHIFFRAR, M AF LORENCEAU, J SHIFFRAR, M TI CONTOUR END-POINTS DO NOT ACT AS CORRESPONDENCE TOKENS AT LOW CONTRAST SO PERCEPTION LA English DT Meeting Abstract C1 UNIV PARIS 05,PSYCHOL EXPTL LAB,CNRS,F-75270 PARIS 06,FRANCE. NASA,AMES RES CTR,VIS GRP,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON, ENGLAND NW2 5JN SN 0301-0066 J9 PERCEPTION JI Perception PY 1991 VL 20 IS 1 BP 84 EP 84 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA GC521 UT WOS:A1991GC52100073 ER PT J AU SCHRAMM, DN AF SCHRAMM, DN TI BIG-BANG NUCLEOSYNTHESIS - THE STANDARD MODEL AND ALTERNATIVES SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT NOBEL SYMP 79 : THE BIRTH AND EARLY EVOLUTION OF OUR UNIVERSE CY JUN 11-16, 1990 CL GRAFTAVALLEN, SWEDEN SP NOBEL FDN ID DECAYING MASSIVE PARTICLE; COSMOLOGICAL CONSTRAINTS; PRIMORDIAL NUCLEOSYNTHESIS; NEUTRON LIFETIME; EARLY UNIVERSE; LITHIUM; NUMBER; HALO; ABUNDANCES; NEUTRINOS AB Big bang nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the big bang cosmological model. This paper reviews the standard homogeneous-isotropic calculation and shows how it fits the light element abundances ranging from He-4 at 24% by mass through H-2 and He-3 at parts in 10(5) down to Li-7 at parts in 10(10). Furthermore, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard scenario. Discussion is presented on the improved observational data as well as the improved neutron lifetime data. Alternate scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, OMEGA-b, remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the conclusion that OMEGA-b congruent-to 0.06. This latter point is the driving force behind the need for non-baryonic dark matter (assuming OMEGA-total = 1) and the need for dark baryonic matter, since OMEGA-visible < OMEGA-b. C1 NASA,CTR FERMILAB ASTROPHYS,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP SCHRAMM, DN (reprint author), UNIV CHICAGO,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 86 TC 10 Z9 10 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1991 VL T36 BP 22 EP 29 DI 10.1088/0031-8949/1991/T36/003 PG 8 WC Physics, Multidisciplinary SC Physics GA FM458 UT WOS:A1991FM45800004 ER PT J AU TURNER, MS AF TURNER, MS TI DARK MATTER IN THE UNIVERSE SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT NOBEL SYMP 79 : THE BIRTH AND EARLY EVOLUTION OF OUR UNIVERSE CY JUN 11-16, 1990 CL GRAFTAVALLEN, SWEDEN SP NOBEL FDN ID SO-INVISIBLE AXIONS; LOCAL MASS DENSITY; RECONCILING THEORETICAL PREJUDICES; STRING-DOMINATED UNIVERSE; LARGE-SCALE STRUCTURE; BACKGROUND-RADIATION; PRIMORDIAL NUCLEOSYNTHESIS; COSMOLOGICAL CONSTANT; THERMAL PRODUCTION; GALACTIC HALOS AB What is the quantity and composition of material in the Universe? This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: Most of the material in the Universe does not give off detectable radiation, i.e., is "dark;" the dark matter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments - structure formation, the temporal Copernican principle, and inflation - and by some observational data. If OMEGA-is indeed unity - or even just significantly greater than 0.1 - then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10(-6) eV to 10(-4) eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three posibilities can be tested by experiments that are either being planned or are underway. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP TURNER, MS (reprint author), NASA,CTR FERMILAB ASTROPHYS,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 175 TC 69 Z9 69 U1 1 U2 3 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1991 VL T36 BP 167 EP 182 DI 10.1088/0031-8949/1991/T36/018 PG 16 WC Physics, Multidisciplinary SC Physics GA FM458 UT WOS:A1991FM45800019 ER PT J AU KOLB, EW AF KOLB, EW TI 1ST-ORDER INFLATION SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT NOBEL SYMP 79 : THE BIRTH AND EARLY EVOLUTION OF OUR UNIVERSE CY JUN 11-16, 1990 CL GRAFTAVALLEN, SWEDEN SP NOBEL FDN ID COUPLED ANHARMONIC OSCILLATORS; PRIMORDIAL BARYON GENERATION; PARTICLE EMISSION RATES; EXTENDED INFLATION; PHASE-TRANSITION; COSMIC STRINGS; FALSE VACUUM; DENSITY PERTURBATIONS; CHAOTIC INFLATION; SYMMETRY-BREAKING AB In the original proposal, inflation occurred in the process of a strongly first-order phase transition. This model was soon demonstrated to be fatally flawed. Subsequent models for inflation involved phase transitions that were second-order, or perhaps weakly first-order; some even involved no phase transition at all. Recently the possibility of inflation during a strongly first-order phase transition has been revived. In this talk I will discuss some models for first-order inflation, and emphasize unique signatures that result if inflation is realized in a first-order transition. Before discussing first-order inflation, I will briefly review some of the history of inflation to demonstrate how first-order inflation differs from other models. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. RP KOLB, EW (reprint author), NASA,CTR FERMILAB ASTROPHYS,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, USA. NR 82 TC 53 Z9 53 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1991 VL T36 BP 199 EP 217 DI 10.1088/0031-8949/1991/T36/021 PG 19 WC Physics, Multidisciplinary SC Physics GA FM458 UT WOS:A1991FM45800022 ER PT J AU AMMAN, M WILKINS, R BENJACOB, E MAKER, PD JAKLEVIC, RC AF AMMAN, M WILKINS, R BENJACOB, E MAKER, PD JAKLEVIC, RC TI ANALYTIC SOLUTION FOR THE CURRENT-VOLTAGE CHARACTERISTIC OF 2-MESOSCOPIC TUNNEL-JUNCTIONS COUPLED IN SERIES SO PHYSICAL REVIEW B LA English DT Note ID EFFECT TRANSISTOR; PARTICLES AB We present a theoretical analysis for a system composed of two mesoscopic tunnel junctions coupled in series. We show that the current-voltage characteristic for this system can be obtained analytically. The usefulness of the model is demonstrated through the fit of experimental data acquired with a cryogenic (4.2 K) scanning tunneling microscope. A simple extension of the model predicts additional structure in the system characteristics when discrete middle electrode states are present. C1 TEL AVIV UNIV,RAYMOND & BEVERLY SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. FORD MOTOR CO,SCI RES LAB,DEARBORN,MI 48121. RP AMMAN, M (reprint author), UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109, USA. NR 16 TC 219 Z9 221 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 1 PY 1991 VL 43 IS 1 BP 1146 EP 1149 DI 10.1103/PhysRevB.43.1146 PN B PG 4 WC Physics, Condensed Matter SC Physics GA EQ745 UT WOS:A1991EQ74500054 ER PT J AU ROGERS, MM AF ROGERS, MM TI THE STRUCTURE OF A PASSIVE SCALAR FIELD WITH A UNIFORM MEAN GRADIENT IN RAPIDLY SHEARED HOMOGENEOUS TURBULENT-FLOW SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID AXISYMMETRIC STRAIN; DISTORTION; DILATATION AB The effect of an arbitrarily oriented mean passive scalar gradient on one-point passive scalar statistics is studied in homogeneous turbulent shear flow in the limit of rapid shearing. By neglecting the nonlinear inertial transfer to small scales an analytical solution for individual Fourier modes is obtained for the case of unity Prandtl number. This solution is used to compute the development of one-point statistics for the velocity and scalar fields in the inviscid limit. Comparisons to direct numerical simulations of the full nonlinear equations for the same flow show that in addition to describing the early time response to the imposed shear, the linear solution gives reasonable estimates of several correlation coefficients for the developed shear flow. RP ROGERS, MM (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 30 TC 47 Z9 47 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD JAN PY 1991 VL 3 IS 1 BP 144 EP 154 DI 10.1063/1.857873 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA EQ013 UT WOS:A1991EQ01300013 ER PT J AU CHASNOV, JR AF CHASNOV, JR TI SIMULATION OF THE KOLMOGOROV INERTIAL SUBRANGE USING AN IMPROVED SUBGRID MODEL SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID HIGH-REYNOLDS-NUMBER; ISOTROPIC TURBULENCE; NUMERICAL-SIMULATION; VELOCITY SPECTRA; BOUNDARY-LAYER; EDDY VISCOSITY; SURFACE-LAYER; TEMPERATURE; SIMILARITY; ORDER AB A subgrid model is developed and applied to a large-eddy simulation of the Kolmogorov inertial subrange. Currently popular subgrid models are derived from models of the turbulent energy equation, resulting in a significant loss of information as a consequence of the statistical averaging performed in going from the Navier-Stokes equation to the energy equation. The subgrid model developed here is based directly on a model of the Navier-Stokes equation. The improved subgrid model contains two terms: an eddy viscosity and a stochastic force. These terms are computed from the EDQNM stochastic model representation of the momentum equation, and from a fully resolved direct numerical simulation. Use of the subgrid model in a forced large-eddy simulation results in an energy spectrum that exhibits a clear k-5/3 power-law subrange with an approximate value Ko = 2.1 of the Kolmogorov constant. RP CHASNOV, JR (reprint author), NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NR 45 TC 123 Z9 126 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD JAN PY 1991 VL 3 IS 1 BP 188 EP 200 DI 10.1063/1.857878 PG 13 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA EQ013 UT WOS:A1991EQ01300018 ER PT J AU RIEDLER, W SCHWINGENSCHUH, K LICHTENEGGER, H MOHLMANN, D RUSTENBACH, J YEROSHENKO, Y ACHACHE, J SLAVIN, J LUHMANN, JG RUSSELL, CT AF RIEDLER, W SCHWINGENSCHUH, K LICHTENEGGER, H MOHLMANN, D RUSTENBACH, J YEROSHENKO, Y ACHACHE, J SLAVIN, J LUHMANN, JG RUSSELL, CT TI INTERACTION OF THE SOLAR-WIND WITH THE PLANET MARS - PHOBOS-2 MAGNETIC-FIELD OBSERVATIONS SO PLANETARY AND SPACE SCIENCE LA English DT Article ID LOCATIONS; SHOCK AB The magnetometers on board the Phobos 2 spacecraft provided the opportunity to study the magnetic environment around Mars, including regions which have never been explored before, such as at low altitudes (down to 850 km above the surface of Mars) and in the tail. The data revealed a bow shock, characterized by a distinct jump in the magnetic field strength and a boundary denoted "planetopause", where the level of turbulence of the magnetic field changes. Inside the planetopause the field remains quiet. Some of the main characteristics of the bow shock and the magnetosheath can be reproduced by computer simulations within the framework of a gas-dynamic model using the observed planetopause as an obstacle for the incoming solar wind. In many spacecraft orbits around Mars, reversals of the B(x)-component were found which are typical for tail crossings. A first analysis of the tail data from the circular orbits at a distance of 2.8 Mars radii showed several cases where the reversal of the tail lobes was controlled by the IMF. This supports the idea of an induced character of the solar wind interaction with Mars outside a distance of about 2.8 Mars radii. However, there are certain features in the magnetic field data which could be interpreted as traces of a weak Martian intrinsic field. C1 INST KOSMOSFORSCH,O-1199 BERLIN,GERMANY. IZMIRAN,TROITSK,USSR. INST PHYS GLOBE,PARIS,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP RIEDLER, W (reprint author), AUSTRIAN ACAD SCI,INST WELTRAUMFORSCH,INFFELDGASSE 12 W,A-8010 GRAZ,AUSTRIA. RI Slavin, James/H-3170-2012; OI Slavin, James/0000-0002-9206-724X; Russell, Christopher/0000-0003-1639-8298 NR 20 TC 29 Z9 31 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN-FEB PY 1991 VL 39 IS 1-2 BP 75 EP 81 DI 10.1016/0032-0633(91)90129-X PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE042 UT WOS:A1991FE04200013 ER PT J AU MURRAY, B NARAEVA, MK SELIVANOV, AS BETTS, BH SVITEK, T KHARLAMOV, VD ROMANOV, AV SANTEE, ML GEKTIN, YM FOMIN, DA PAIGE, DA PANFILOV, AS CRISP, D HEAD, JW MURCHIE, SL MARTIN, TZ AF MURRAY, B NARAEVA, MK SELIVANOV, AS BETTS, BH SVITEK, T KHARLAMOV, VD ROMANOV, AV SANTEE, ML GEKTIN, YM FOMIN, DA PAIGE, DA PANFILOV, AS CRISP, D HEAD, JW MURCHIE, SL MARTIN, TZ TI PRELIMINARY ASSESSMENT OF TERMOSKAN OBSERVATIONS OF MARS SO PLANETARY AND SPACE SCIENCE LA English DT Article ID MARTIAN ATMOSPHERE; HISTORY; MISSION AB In February and March, 1989, the Termoskan instrument onboard the Phobos '88 spacecraft acquired a limited set of very high resolution observations of the 8-12-mu-m thermal emission from Mars' equatorial regions. Simultaneous and coincident observations were acquired in the 0.5 to 1.0-mu-m region also. We have evaluated quantitatively about 25% of those data and find close agreement with the lower-resolution Viking Orbiter Infrared Thermal Mapper (IRTM) observations, demonstrating the accuracy of the Termoskan system. Termoskan's thermal emission panoramas display limb brightening at the morning limb, which we interpret as arising from the presence of a diurnal ice crystal haze there. Detached hazes at high altitude also are evident in the visible panorama of the evening limb. The Phobos '88 orbit enabled Termoskan to record the visible shadow from the Martian moonlet Phobos and to measure the surface thermal response to that shadow's passage. Analysis of one such data set shows that the uppermost fraction of a millimeter is two to four times more insulating than the uppermost centimeters sensed by the IRTM experiment. The Termoskan data are of direct importance to the planning and execution of the PMIRR and TES experiments of the U.S. Mars Observer mission to be launched in 1992. An improved version of Termoskan is planned for the Mars '94 mission of the U.S.S.R. Those data will be of still higher surface resolution and, thus, complement well the expected PMIRR and TES global data sets. C1 MOSCOW SPACE DEVICES INST,MOSCOW,USSR. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. CALTECH,JET PROP LAB,PASADENA,CA 91109. BROWN UNIV,PROVIDENCE,RI 02912. RP MURRAY, B (reprint author), CALTECH,PASADENA,CA 91125, USA. RI Murchie, Scott/E-8030-2015 OI Murchie, Scott/0000-0002-1616-8751 NR 17 TC 10 Z9 10 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN-FEB PY 1991 VL 39 IS 1-2 BP 237 EP 265 DI 10.1016/0032-0633(91)90147-3 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE042 UT WOS:A1991FE04200031 ER PT J AU AVANESOV, G ZHUKOV, B ZIMAN, Y KOSTENKO, V KUZMIN, A MURAVEV, V FEDOTOV, V BONEV, B MISHEV, D PETKOV, D KRUMOV, A SIMEONOV, S BOYCHEVA, V UZUNOV, Y WEIDE, GG HALMANN, D POSSEL, W HEAD, J MURCHIE, S SCHKURATOV, YG BERGHANEL, R DANZ, M MANGOLDT, T PIHAN, U WEIDLICH, U LUMME, K MUINONEN, K PELTONIEMI, J DUXBURY, T MURRAY, B HERKENHOFF, K FANALE, F IRVINE, W SMITH, B AF AVANESOV, G ZHUKOV, B ZIMAN, Y KOSTENKO, V KUZMIN, A MURAVEV, V FEDOTOV, V BONEV, B MISHEV, D PETKOV, D KRUMOV, A SIMEONOV, S BOYCHEVA, V UZUNOV, Y WEIDE, GG HALMANN, D POSSEL, W HEAD, J MURCHIE, S SCHKURATOV, YG BERGHANEL, R DANZ, M MANGOLDT, T PIHAN, U WEIDLICH, U LUMME, K MUINONEN, K PELTONIEMI, J DUXBURY, T MURRAY, B HERKENHOFF, K FANALE, F IRVINE, W SMITH, B TI RESULTS OF TV IMAGING OF PHOBOS (EXPERIMENT VSK-FREGAT) SO PLANETARY AND SPACE SCIENCE LA English DT Article ID PHOTOMETRY; SURFACE; DEIMOS; SATELLITES AB From February to March 1989 the Phobos 2 spacecraft took 37 TV images of Phobos at a distance of 190-1100 km. These images complement Mariner-9 and Viking data by providing higher-resolution coverage of a large region West of the crater Stickney (40-160 W) and by providing disk-resolved measurements of surface brigthness at a greater range of wavelengths and additional phase angles. These images have supported updated mapping and characterization of large craters and grooves, and have provided additional observations of craters' and grooves' bright rims. Variations in surface visible/near-infrared color ratio of almost a factor of 2 have been recognized; these variations appear to be associated with the ejecta of specific large impact craters. Updated determinations of satellite mass and volume allow calculation of a more accurate value of bulk density, 1.90 +/- 0.1 g cm-3. This is significantly lower than the density of meteoritic analogs to Phobos' surface, suggesting a porous interior perhaps containing interstitial ice. C1 SPACE RES INST,SOFIA,BULGARIA. ZENT INST KYBERNET & INFORMAT PROZESSE,BERLIN,GERMANY. BROWN UNIV,PROVIDENCE,RI 02912. KHARKOV UNIV,KHARKOV 310077,UKRAINE,USSR. INST KOSMOSFORSCH,O-1199 BERLIN,GERMANY. UNIV HELSINKI,SF-00130 HELSINKI 13,FINLAND. CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,PASADENA,CA 91125. UNIV HAWAII,HONOLULU,HI 96822. UNIV MASSACHUSETTS,AMHERST,MA 01003. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP AVANESOV, G (reprint author), ACAD SCI USSR,SPACE RES INST,PROFSOYUZNAYA 84-32,MOSCOW 117810,USSR. RI Murchie, Scott/E-8030-2015; Peltoniemi, Jouni/F-2982-2014 OI Murchie, Scott/0000-0002-1616-8751; Peltoniemi, Jouni/0000-0002-4701-128X NR 40 TC 25 Z9 25 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN-FEB PY 1991 VL 39 IS 1-2 BP 281 EP 295 DI 10.1016/0032-0633(91)90150-9 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE042 UT WOS:A1991FE04200034 PM 11538495 ER PT J AU KSANFOMALITY, L MURCHIE, S BRITT, D DUXBURY, T FISHER, P GOROSHKOVA, N HEAD, J KUHRT, E MOROZ, V MURRAY, B NIKITIN, G PETROVA, E PIETERS, C SOUFFLOT, A ZHARKOV, A ZHUKOV, B AF KSANFOMALITY, L MURCHIE, S BRITT, D DUXBURY, T FISHER, P GOROSHKOVA, N HEAD, J KUHRT, E MOROZ, V MURRAY, B NIKITIN, G PETROVA, E PIETERS, C SOUFFLOT, A ZHARKOV, A ZHUKOV, B TI PHOBOS - SPECTROPHOTOMETRY BETWEEN 0.3 AND 0.6 MU-M AND IR-RADIOMETRY SO PLANETARY AND SPACE SCIENCE LA English DT Article ID INFRARED OBSERVATIONS; SURFACE; REFLECTANCE; DEIMOS; VIKING AB A 0.3-0.6-mu-m UV-visible spectrophotometer and a 5-50-mu-m radiometer in the KRFM experiment on Phobos 2 measured two groundtracks in the equatorial region of Phobos. Preliminary results indicate that three surface units can be recognized on the basis of differing UV-visible spectral reflectance properties. One of the units is most comparable spectrally to optically darkened mafic material, and a second is comparable either to anhydrous carbonaceous chondrite or to blackened mafic material. Spectral properties of the third unit do not resemble those of known meteorite types. Brightness temperatures measured by the radiometer are consistent with a typical surface thermal inertia of 1-3 x 10(-3) cal/(cm2 deg s1/2), as suggested by previous investigations, implying a lunar-like regolith texture. At least one area of possibly higher thermal inertia has been tentatively identified, where a large degraded crater is crossed by several grooves. These results indicate significant lateral heterogeneity in the optical and textural properties of Phobos's surface. C1 BROWN UNIV,DEPT GEOL SCI,PROVIDENCE,RI 02912. CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,PASADENA,CA 91125. INST ASTROPHYS SPATIALE,F-91406 ORSAY,FRANCE. RP KSANFOMALITY, L (reprint author), MOSCOW SPACE RES INST,PROTSOYUZNAYA 84-32,GSP 7,MOSCOW 117810,USSR. RI Murchie, Scott/E-8030-2015 OI Murchie, Scott/0000-0002-1616-8751 NR 26 TC 13 Z9 13 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN-FEB PY 1991 VL 39 IS 1-2 BP 311 EP 326 DI 10.1016/0032-0633(91)90152-Z PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE042 UT WOS:A1991FE04200036 ER PT J AU DUXBURY, TC AF DUXBURY, TC TI AN ANALYTIC MODEL FOR THE PHOBOS SURFACE SO PLANETARY AND SPACE SCIENCE LA English DT Article AB Analytic expressions are derived to model the surface topography and the normal to the surface of Phobos. The analytic expressions are comprised of a spherical harmonic expansion for the global figure of Phobos, augmented by addition terms for the large crater Stickney and other craters. Over 300 craters were measured in more than 100 Viking Orbiter images to produce the model. In general, the largest craters were measured since they have a significant effect on topography. The topographic model derived has a global spatial and topographic accuracy ranging from about 100 m in areas having the highest resolution and convergent, stereo coverage, up to 500 m in the poorest areas. C1 CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109. NR 10 TC 24 Z9 25 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN-FEB PY 1991 VL 39 IS 1-2 BP 355 EP 376 DI 10.1016/0032-0633(91)90157-6 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA FE042 UT WOS:A1991FE04200041 ER PT J AU FEWELL, LL FINNEY, L AF FEWELL, LL FINNEY, L TI AN ESCA STUDY OF ATOMIC OXYGEN INTERACTIONS WITH PHOSPHAZENE-COATED POLYIMIDE FILMS SO POLYMER COMMUNICATIONS LA English DT Article DE ESCA; POLYIMIDE FILMS; PHOSPHAZENE AB Metallic as well as most non-metallic materials experience oxidation and mass loss via surface erosion in low earth orbit as shown in previous space shuttle flights. This study is an evaluation of select polyphosphazene polymers and their resistance to atomic oxygen attack. Electron spectroscopy for chemical analysis examinations of the surfaces of polyphosphazene coatings were monitored for microstructural changes induced during exposures to atomic oxygen. Sample exposures in oxygen plasmas and O(3P) beam were compared as to their effect on surface compositional changes in the polyphosphazene coating. High resolution line scans revealed rearrangements in the polymer backbone and scissioning reactions involving fluorocarbon units of long chain fluoroalkoxy pendant groups. Atom per cents and peak areas of all species provided a detailed profile of the microstructural changes induced in phosphazene polymers as a result of exposures to atomic oxygen. C1 SURFACE SCI LABS,MT VIEW,CA 94043. RP FEWELL, LL (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 7 TC 21 Z9 21 U1 0 U2 0 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0263-6476 J9 POLYM COMMUN PY 1991 VL 32 IS 13 BP 393 EP 396 PG 4 WC Polymer Science SC Polymer Science GA GF021 UT WOS:A1991GF02100003 ER PT J AU PATER, RH AF PATER, RH TI 371-DEGREES-C (700-DEGREES-F) PROPERTIES OF CELION 6000 N-PHENYLNADIMIDE MODIFIED PMR POLYIMIDE COMPOSITES SO POLYMER ENGINEERING AND SCIENCE LA English DT Article AB The 371-degrees-C (700-degrees-F) properties of Celion 6000/N-phenylnadimide modified PMR-15 polyimide composites were investigated to determine the feasibility of using these materials at a 371-degrees-C (700-degrees-F) service temperature. The processing characteristics and physical and mechanical properties of the composite systems are presented. The results of the 371-degrees-C thermooxidative stability study suggest that the composite materials can be considered for short-term (at least 100 hours) application at 371-degrees-C. RP PATER, RH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 28 TC 8 Z9 10 U1 1 U2 1 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD JAN PY 1991 VL 31 IS 1 BP 14 EP 19 DI 10.1002/pen.760310104 PG 6 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA ET209 UT WOS:A1991ET20900003 ER PT J AU PATER, RH AF PATER, RH TI INTERPENETRATING POLYMER NETWORK APPROACH TO TOUGH AND MICROCRACKING RESISTANT HIGH-TEMPERATURE POLYMERS .2. LARC-RP41 SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID COMPOSITES AB Recently, we reported on the interpenetrating polyimide network (IPN) approach to develop tough and microcracking resistant high temperature matrix resins for use in aircraft/aerospace structural components. One such polymer developed is designated LaRC-RP40. This new simultaneous semi-IPN was prepared from easy-to-process but brittle crosslinking PMR-15 and tough but difficult-to-process linear NR-150B2. Significantly improved toughness, microcracking resistance, and glass transition temperature over PMR-15 were realized from the combination. These property improvements were achieved without compromising ease of processing, high temperature mechanical performance, and cost effectiveness compared to PMR-15. These results encouraged us to further explore this approach for the development of a wider range of polymers of basic technological and economic interest. In the present work, we combine crosslinking PMR-15 and linear LaRC-TPI to provide a new sequential semi-2-IPN called LaRC-RP41. The physical and mechanical properties of the neat resin and composite reinforced with graphite fibers are presented. The phase morphology and phase stability of the neat resin and composite studied by various techniques are also discussed. RP PATER, RH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 13 TC 28 Z9 33 U1 0 U2 4 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD JAN PY 1991 VL 31 IS 1 BP 20 EP 27 DI 10.1002/pen.760310105 PG 8 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA ET209 UT WOS:A1991ET20900004 ER PT J AU PATER, RH AF PATER, RH TI INTERPENETRATING POLYMER NETWORK APPROACH TO TOUGH AND MICROCRACKING RESISTANT HIGH-TEMPERATURE POLYMERS .3. LARC-RP71 SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID COMPOSITES; POLYIMIDE; BLENDS AB A high performance semi-interpenetrating polymer network (semi-IPN) has been synthesized from Thermid-600 and LARC-TPI. Notable improvements in resin fracture toughness and graphite fiber reinforced composite microcracking resistance over the unmodified Thermid-600 neat resin and composite have been realized. The chemistry, processing, physical and mechanical properties, and phase morphology of the neat resin and composite reinforced with graphite fibers are presented. RP PATER, RH (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 18 TC 15 Z9 17 U1 1 U2 6 PU SOC PLASTICS ENG INC PI BROOKFIELD CENTER PA 14 FAIRFIELD DR, BROOKFIELD CENTER, CT 06804-0403 SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD JAN PY 1991 VL 31 IS 1 BP 28 EP 33 DI 10.1002/pen.760310106 PG 6 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA ET209 UT WOS:A1991ET20900005 ER PT J AU ANDERSON, JD SLADE, MA JURGENS, RF LAU, EL NEWHALL, XX STANDISH, EM AF ANDERSON, JD SLADE, MA JURGENS, RF LAU, EL NEWHALL, XX STANDISH, EM TI RADAR AND SPACECRAFT RANGING TO MERCURY BETWEEN 1966 AND 1988 SO PROCEEDINGS ASTRONOMICAL SOCIETY OF AUSTRALIA LA English DT Article; Proceedings Paper CT 5TH ASIAN - PACIFIC REGIONAL ASTRONOMY MEETING CY JUL 16-20, 1990 CL UNIV NEW SOUTH WALES, SYDNEY, AUSTRALIA SP INT ASTRON UNION, ANGLO AUSTR OBSERV, AUSTR DEF FORCE ACAD, AUSTR TELESCOPE NATL FACIL, MT STROMLO & SIDING SPRING OBSERV, AUSTR NATL UNIV HO UNIV NEW SOUTH WALES AB Improved solutions have been obtained for the orbit and equatorial cross-section of Mercury using radar ranging data spanning 22 years. These data have yielded new results on the precession of Mercury's perihelion and better limits on a possible time variation in the gravitational constant G. RP ANDERSON, JD (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 4 TC 15 Z9 15 U1 0 U2 0 PU C S I R O PUBLICATIONS PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD VICTORIA 3066, AUSTRALIA SN 0066-9997 J9 P ASTRON SOC AUST JI Proc. Astron. Soc. Aust. PY 1991 VL 9 IS 2 BP 324 EP 324 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA JM728 UT WOS:A1991JM72800051 ER PT J AU PHINNEY, WC AF PHINNEY, WC TI LUNAR ANORTHOSITES, THEIR EQUILIBRIUM MELTS AND THE BULK MOON SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID DISTRIBUTION COEFFICIENTS; PARTITION-COEFFICIENTS; TERRESTRIAL PLANETS; TRACE-ELEMENTS; LIQUID; SR; BA; CLINOPYROXENE; PLAGIOCLASE; RB AB Melts from which lunar anorthosites formed and the parent liquids from which these melts were derived have been estimated from plagioclase compositions and partition coefficients for several elements. The task is complicated by uncertainty about redistribution of elements during high-temperature recrystallization of the anorthosites. Iron, Mg, Co, and Ni were redistributed in plagioclase during recrystallization and cannot be used to calculate their concentrations in equilibrium melts. Rare earth elements, Ba, , Th, Ta, Sr, Hf, Ti, Sc, and Cr have concentrations that are very similar to calcic plagioclases in terrestrial Archean anorthosites and have been used to calculate equilibrium liquids for lunar anorthosites. The predicted equilibrium melt for the beginning of plagioclase crystallization displays a flat, unfractionated REE pattern at about 10 times chondrites and apparently proceeds with fractionation to at least 30 times chondrites. Barium, Th, Ta, Sr, Hf, and Ti also occur at about 10 times chondrites in the predicted melts. Relative to REEs and these other elements, Sc is depleted to about 4 times chondrites and Cr is depleted to almost 0.01 chondrites probably because of their more compatible behavior in mantle minerals. Potassium and Rb are present in the melt at less than chondritic abundances. Estimates of bulk D for the lunar mantle were used with the anorthosite equilibrium melt at the of plagioclase crystallization to predict the initial melts from which the anorthosites were derived. None of the models for the initial melt composition provides ideal values for all components, Given complete melting of the silicate portion of the Moon, in order for the initial melt to contain incompatible elements at previous estimates for the bulk silicate composition of the Moon, plagioclase must start crystallizing at 75% to 80% solidification of the melt. For this condition to be met, however, the compatible elements, Sc and Cr, in the initial melt are low by factors of about 3 and 5, respectively. For the incompatible elements, as well as Sc and Cr, to be at the same fraction of previously estimated bulk Moon values requires that plagioclase start crystallizing at about 90% solidification, but for this value of solidification the elements are all present in the initial melt at only about 50% of the concentrations expected in the bulk silicate portion of the Moon. Given partial melting models of the silicate portion of the Moon, the high proportion of melting required to produce an adequate amount of lunar crust produces a problem in the need for extensive decoupling of incompatible elements from Sc and Cr. The models that provide the fewest discrepancies require extensive melting of between 75% and 100% of the lunar mantle to produce a lunar crust that constitutes 13-15% of the Moon's volume. RP PHINNEY, WC (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, MAIL CODE SN2, HOUSTON, TX 77058 USA. NR 97 TC 16 Z9 16 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 USA SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 29 EP 49 PG 21 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300004 ER PT J AU JAMES, OB LINDSTROM, MM MCGEE, JJ AF JAMES, OB LINDSTROM, MM MCGEE, JJ TI LUNAR FERROAN ANORTHOSITE-60025 - PETROLOGY AND CHEMISTRY OF MAFIC LITHOLOGIES SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID MOON; CRUST; PETROGENESIS; MELT AB Lunar ferroan anorthosites are generally thought to be relics of the Moon's primordial crust, formed by flotation and accumulation of plagioclase atop a differentiating, Moon-wide magma ocean. Our research is aimed at better understanding the petrogenesis of ferroan anorthosites by establishing the exact nature and causes of compositional variations in the minerals of these rocks. We have studied 11 splits from the mafic-mineral-rich part of anorthosite 60025. All splits were analyzed by INAA, and five were studied intensively by petrologic techniques; these were three mafic-mineral splits, a plagioclase split, and a whole-rock split. The splits have widely varied modes; dominant minerals are plagioclase, inverted pigeonite, and olivine. All splits have similar cataclastic textures and show textural evidence of at least two episodes of deformation. The mafic-mineral splits and the plagioclase split contain homogeneous mafic minerals (relatively magnesian and relatively ferroan, respectively) and are probably monomict. The whole-rock split contains mafic minerals having a wide range of compositions and is probably polymict, a mechanical mixture of several ferroan anorthosite parent rocks. The parent rocks were a group of coarse-grained igneous cumulates that differed widely in mode and mg' of their mafic minerals. Our studies of rare-earth distribution in the splits indicate that the rare-earth patterns for all splits can be duplicated satisfactorily assuming that the equilibrium liquids had flat, or nearly flat, chondrite-normalized rare-earth patterns. The equilibrium liquid for the mafic-mineral splits appears to have been richer in rare-earth elements than the equilibrium liquid for the plagioclase split. Minor-element compositions of the pyroxenes from all splits show trends suggesting that they all could have formed from a single, evolving parent magma. The plagioclases in all splits are virtually identical. They show good negative correlations of MgO, FeO, and K2O with An content; trends for these minor elements vs. An are virtually the same in all splits, no matter what the composition of the associated mafic minerals. The nature of the trends indicates that the variations are preserved igneous variations. Our data indicate that in ferroan anorthosites An content in plagioclase and mg' of associated mafic minerals are not strongly correlated. This observation suggests that complex processes operated during crystallization of these rocks. The nature of these processes is as yet unresolved. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP JAMES, OB (reprint author), US GEOL SURVEY,959 NATL CTR,RESTON,VA 22092, USA. NR 50 TC 23 Z9 23 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 63 EP 87 PG 25 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300006 ER PT J AU MARVIN, UB LINDSTROM, MM HOLMBERG, BB MARTINEZ, RR AF MARVIN, UB LINDSTROM, MM HOLMBERG, BB MARTINEZ, RR TI NEW OBSERVATIONS ON THE QUARTZ MONZODIORITE-GRANITE SUITE SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID KREEP; ORIGIN; PETROLOGY; ROCKS AB Petrographic studies and major- and trace-clement analyses of four fragments of quartz monzodiorite (QMD) and one of granite from the 2-4 mm fraction of Apollo 15 soil sample 15403 demonstrate the extreme variations found in small particles. One QMD clast, 15403,71A, contains 18% modal phosphates in grains >1 mm long. This is the most phosphate-rich lithology reported from the Moon. A second QMD clast, 15403,7001, contains only a few 0.04-mm grains of phosphates. Clearly, QMD particles must be viewed as a suite and their compositions averaged for purposes of calculating modes of origin. Soil 15403 was derived from rock 15405, which consists of a dark, KREEPy impact melt containing fragments of QMD, granite, KREEP basalt, and one clast of more primitive alkali norite. It seems most probable to us that QMD and granites were formed mainly by the fractional crystallization of a KREEP-rich basaltic magma. The Apollo 15 KREEP basalts cannot represent this parent magma because age determinations show that QMD and granites predate the KREEP basalts. We suggest that QMD and granite crystallized from plutons parental to KREEP basalt magmas and that the alkali norite clast in 19405, although not representative of that magma, is part of the precursor plutonic rock. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP MARVIN, UB (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138, USA. NR 34 TC 24 Z9 24 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 119 EP 135 PG 17 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300009 ER PT J AU WENTWORTH, SJ MCKAY, DS AF WENTWORTH, SJ MCKAY, DS TI APOLLO-14 GLASSES AND THE ORIGIN OF LUNAR SOILS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article AB Homogeneous and heterogeneous glass clasts in four Apollo 14 regolith breccias ( 14042, 14301, 14313, and 14315) were analyzed for major elements by means of electron microprobe for comparison with soil glass data. Glass types in the Apollo 14 samples, including the breccias and the soils, are dominated by highland compositions, which include KREEP, LKFM, and highland basalt (feldspathic) varieties. Only one of the studied breccias, 14042, has a highland glass population similar to those of local Apollo 14 soils. The other three breccias have significantly different glass populations. Breccia 14301 is distinct in that it is enriched in KREEP glasses with high contents of K2O (greater-than-or-equal-to 1 wt%), which are similar in composition to Apollo 12 ropy glasses. One ultra-Mg' (Mg/Mg + Fe greater-than-or-equal-to 0.90) glass vas identified in 14301 and the Apollo 14 comparison soil; the ultra-Mg' glasses are Si-poor, similar to one of the types of ultra-Mg' glasses previously found in Apollo 16 samples. These glasses have some similarities to HASP glasses. One HASP glass was identified in breccia 14313; it is a typical Apollo 14-type HASP glass as defined by Vaniman ( 1990). Differences in glass populations among the regolith breccias reflect slight differences in bulk regolith breccia compositions determined by other workers. Of the four regolith breccias of this study, only 14042 could be made from local present-day soils. The Apollo 14 regolith breccias might represent ancient soils that were closed to further regolith processing at an early time by breccia formation. Some of the ancient soils escaped breccia formation and closure; however, over geologic time these soils slowly evolved into die present-day soils by meteorite impact processing, by mixing together in various proportions, and by changes made by the addition of lithic fragments and other components. Another possibility is that the Apollo 14 soils are made from mixtures of comminuted regolith breccias. ff the regolith breccias are made from an evolving soil, the most likely time sequence from oldest to youngest is: 14301, 14313, and 14042. Aluminous breccia 14315 is so different from the others with respect to composition and glass populations that it might be exotic to the Apollo 14 site. However, if the present-day soil is made from comminution of local regolith breccia units, an exotic origin for 14315 is not required. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP WENTWORTH, SJ (reprint author), LOCKHEED ENGN & SCI CO,MAIL CODE C23,2400 NASA RD 1,HOUSTON,TX 77058, USA. NR 22 TC 3 Z9 3 U1 1 U2 3 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 185 EP 192 PG 8 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300013 ER PT J AU BASU, A MOLINAROLI, E BLOM, ME WENTWORTH, SJ MCKAY, DS AF BASU, A MOLINAROLI, E BLOM, ME WENTWORTH, SJ MCKAY, DS TI PETROLOGY AND PROVENANCE OF APOLLO-15 STATION-6 CORE-15009 AND ITS BEARING ON SITE GEOLOGY SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID HEAVENLY DETECTIVE STORY; LUNAR MINERALOGY; CHEMISTRY; REGOLITH; ORIGIN AB We have made petrographic and microprobe studies of six soil samples from six different levels of the 30-cm-deep single-drive tube core 15009 obtained from the regolith of the Apennine Front at Station 6 of the Apollo 15 site. In 1995 grains in the 90-150-mum size fraction the agglutinate abundance ranges from about 23% to about 40%, indicating that the soils are submature. A negative correlation between the abundances of agglutinates and glasses may mean that glasses were emplaced first and were reworked significantly into agglutinates. Abundances of other major particle types do not show similar mutual correlations. However, the proportion of crystalline matrix breccias in total breccias and of green glasses in total glass correlate very well with each other, suggesting the same immediate sources of these two soil components. Fragments of green glass and crystalline matrix breccias probably coexisted on the slopes of the Apennine Front by the time fragments of mare basalts and ropy glasses were ballistically transported to the slope. Chemical compositions of over 550 monomineralic fragments in the 90-150-mum size fraction and petrographic study of 208 basalt particles in the 150-250-mum and the 250-500-mum size fraction suggest that highland rocks, KREEP basalts, olivine-normative mare basalts, and quartz-normative mare basalts contributed 9%, 40%, 14%, and 37%, relatively, to this regolith column. The quartz-normative basalts (QNB) are subordinate to the olivine-normative basalts (ONB) in the Apollo 15 site near the Hadley Rille and away from the Apennine Front; the reverse is the case in the regolith of the Apennine Front away from the mare plains, i.e., QNB becomes dominant near the Front. We envisage a scenario for the stratigraphic framework of the Apollo 15 site in which quartz-normative basalts underlie olivine-normative basalts at the top near the Rille, and the former (QNB) and the regolith immediately above it (QNB) offlap onto the mare-Front contact as the olivine-normative basalt thins out toward the Front. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. LOCKHEED ENGN MANAGEMENT & SCI CO,HOUSTON,TX 77058. RP BASU, A (reprint author), INDIANA UNIV,DEPT GEOL,BLOOMINGTON,IN 47405, USA. RI Molinaroli, Emanuela /F-6036-2014 NR 41 TC 0 Z9 0 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 221 EP 228 PG 8 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300015 ER PT J AU JONES, JH WALKER, D AF JONES, JH WALKER, D TI THERMAL-DIFFUSION IN METAL-SULFIDE LIQUIDS - EARLY RESULTS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID TRACE-ELEMENT FRACTIONATION; FE-NI-S; IRON-METEORITES; SOLIDIFICATION; SEGREGATION; SULFUR; ALLOYS AB Preliminary thermal diffusion experiments on metal-sulfide liquids indicate that the Soret effect can be of comparable magnitude in metallic system as in silicate systems. In the Fe-Ni-S-P system, S segregates to the hot end of the diffusion couple, P and Fe segregate to the cold end, Ni remains almost unaffected, and the magnitude of the P Soret coefficient increases as S increases. This is because the nonideal interactions between S and P increase dramatically as the concentration of either element increases. The Soret coefficient for P changes in approximate accordance with the model of Jones and Malvin (1990) for changes in (P)D(solid metal/liquid metal). This observation reinforces the Jones and Malvin model and provides a basis for predicting the magnitude of Soret coefficients for minor elements in systems that have not yet been explored experimentally. The sense of the Soret segregation, with P going to the cold end and S going to the hot end, is in accordance with the predictions of Malvin et al. (1986), who speculated that the crystal-pulling experiments of Sellamuthu and Goldstein (1985) might have been influenced by the Soret effect. C1 COLUMBIA UNIV,DEPT GEOL SCI,PALISADES,NY 10964. COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. RP JONES, JH (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 13 TC 4 Z9 4 U1 0 U2 1 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 367 EP 373 PG 7 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300025 ER PT J AU MOORE, HJ THOMPSON, TW AF MOORE, HJ THOMPSON, TW TI A RADAR-ECHO MODEL FOR MARS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID PHYSICAL-PROPERTIES; SURFACE PROPERTIES; SITES AB We have developed a radar-echo model for Mars based on 12.6-cm continuous-wave radio transmissions backscattered from the planet. In our model, Mars' surface is divided into radar map units that are based on generalized geologic map units; the radar map units are further subdivided using thermal inertias because the geologic units are insufficient to account for the quasispecular echoes. For cratered uplands and northern plains units, model depolarized and polarized diffuse echoes are uniformly bright, but polarized-diffuse echoes are three times stronger than the depolarized ones. For volcanic units, depolarized and polarized-diffuse echoes are Lambertian and of equal strength. Quasispecular echoes are computed using Hagfors' scattering law. Assignments of depolarized-echo strengths, normal reflectivities, and root-mean-square (rms) slopes for the radar map units were guided by experience, thermal inertias, and data on quasispecular echoes, and then adjusted by trial and error methods to best fit the data. Regional slopes are not included in the model. Our model contains 118 radar-scattering units. The most important ones can be characterized as follows: (1) extensive cratered uplands (background) with weak depolarized echoes (0.01), average thermal inertias, moderate reflectivities (0.095), and moderate rms slopes (3.2-degrees); (2 ) volcanic units of the Tharsis, Elysium, and Amazons regions with strong depolarized echoes (0.04-0.133), low thermal inertias, small reflectivities (0.025-0.050), and large rms slopes (6-degrees-20-degrees); and (3) northern plains units with moderate to strong depolarized echoes (0.017-0.045), moderate to very high thermal inertias, moderate to large reflectivities (0.075-0.15), and moderate rms slopes (3-degrees-5-degrees). Arabia, an extensive unit of upland that is mantled by dust, has a weak depolarized echo (0.007), low thermal inertia, small reflectivity (0.05), and small rms slope (3.0-degrees ). Like the 1986 Goldstone observations along 7-degrees-S: (1) model depolarized-echo total cross sections vary with longitude as a one-cycle curve with a maximum near 135-degrees and a minimum near 330-degrees-W; (2) model polarized-echo total cross sections vary with longitude as a two-cycle curve with maxima near 30-degrees and 240-degrees-W and minima near 130-degrees and 330-degrees-W; (3) model ratios of depolarized-and polarized-echo total cross sections vary with longitude as a one-cycle curve; and (4) model depolarized- and polarized-echo spectra, as well as ratios of the two, resemble the complex observed spectra. Our model also broadly matches the variation in depolarized- and polarized-echo total cross sections (and their ratios) observed by Arecibo in 1980-1982 along 22-degrees-N. Our model illustrates the complexity of echo spectra that arises from a mixture of surface units with different scattering properties. We also conclude that there are two dominant populations of surfaces that have distinct echo properties and that there is general agreement between the quasispecular echo reflectivities of our model and those of many other radar observations of Mars. C1 JET PROP LAB,PASADENA,CA 91109. RP MOORE, HJ (reprint author), US GEOL SURVEY,345 MIDDLEFIELD RD,MENLO PK,CA 94025, USA. NR 32 TC 5 Z9 5 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 457 EP 472 PG 16 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300032 ER PT J AU HARTMETZ, CP GIBSON, EK BLANFORD, GE AF HARTMETZ, CP GIBSON, EK BLANFORD, GE TI IN-SITU EXTRACTION AND ANALYSIS OF VOLATILE ELEMENTS AND MOLECULES FROM CARBONACEOUS CHONDRITES SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID AQUEOUS ALTERATION; PHYLLOSILICATES; METEORITES; INDICATORS AB Five carbonaceous chondrites, Allende (CV3), Coolidge (CV4), Felix (CO3), Murchison (CM2), and Orgueil (CI1), have been examined for in situ volatiles at the 30-50-mum scale using a lase microprobe mass spectrometer. The ratios of total volatiles released from Murchison, Coolidge, Felix, and Allende compared to Orgueil (Orgueil = 1) are 0.9, 0.54, 0.49, and 0.37, respectively. Various types of alteration were apparent in the types and overall quantities of volatiles released from this suite of carbonaceous chondrites. Aqueous alteration was apparent in the volatile inventories of Orgueil and Murchison, as well as terrestrial weathering in Coolidge and thermal metamorphism in Allende. Orgueil contains about twice the amount of water as Murchison, 7 times that in Coolidge, 27 times that in Felix, and 48 times that in Allende. The laser microprobe study revealed that sulfide and S-bearing phases exist throughout the ground-mass matrix of Murchison and Orgueil, whereas Allende contains localized sulfide clasts. Significant differences in volatile abundances at the 30-50-mum scale were observed in the mass spectra from matrix, inclusions, and chondrules within Allende and Murchison. An ameboid olivine aggregate in Allende released much less total volatiles than other regions in Allende and the other meteorites. In both Allende and Murchison, spheres, of Fe-Ni metal with matrix-like rims (approximately 0.05 mm in diameter) released strikingly similar kinds and amounts of volatiles. Murchison matrix generally contains more volatiles and, specifically, higher CO2 and sulfide than its inclusions and chondrules. These differences may be the result of the fine-grained nature of the matrix, which allowed fluids to flow through it (reaction between sample and fluids increases the volatile content of a sample). Significant differences in volatiles were also observed in heavily weathered, sawed, and freshly broken surfaces of Coolidge. C1 UNIV HOUSTON CLEAR LAKE, COLL SCI & TECHNOL, HOUSTON, TX 77058 USA. RP HARTMETZ, CP (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, PLANETARY SCI BRANCH, MAIL CODE SN2, HOUSTON, TX 77058 USA. NR 35 TC 1 Z9 1 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 USA SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 527 EP 539 PG 13 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300037 ER PT J AU HARTMETZ, CP GIBSON, EK BLANFORD, GE AF HARTMETZ, CP GIBSON, EK BLANFORD, GE TI ANALYSIS OF VOLATILES PRESENT IN INTERPLANETARY DUST AND STRATOSPHERIC PARTICLES COLLECTED ON LARGE-AREA COLLECTORS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID AEROSOLS; CARBON AB Six ''chondritic'' interplanetary dust particles (IDPs) and 22 other stratospheric particles have been analyzed for volatiles using a laser microprobe/mass spectrometer to extract volatile elements and molecules from particles that are greater-than-or-equal-to 10 mum. Previous studies have shown that particles were contaminated during their collection and curation. An analysis of these compounds allows us to differentiate between indigenous and contaminant species. Volatiles from the contaminants (silicone oil, freon, and hexane) are always present in background-subtracted spectra from IDPs, despite the curators' attempts to remove contaminants with a hexane rinse. After examining several possible improvements in the hexane rinsing technique, we suggest that longer, more thorough rinsing with hexane will reduce contaminant levels. In previous studies. certain chondritic IDPs released little or no indigenous volatiles, and this was the case for two IDPs in this study (L2001*D3 released only O2, and L2004*D3 released only O2 and H2S and a small amount of m/z = 92 toluene). While other chondritic particles released many indigenous volatiles, some of them in large quantities [e.g., L2003*E3 released many methyl- and ethyl-hydrocarbon species, O2, CO2, and many high-molecular-weight (m/z = 65, 66, 67, 78, 79, 93, and 95) hydrocarbons. Two of these volatile-rich particles (L2003*D2 and L2003*E3) from the same large area collector have similar indigenous volatiles and major elements, suggesting that they should be paired. Both IDPs released low- and high-molecular-weight hydrocarbon fragments, CO2, and C. These volatile fragments are similar to prominant hydrocarbon species formed during laser microprobe analysis of some CM chondrites (e.g., Murray), suggesting that the major sources of hydrocarbons in these two IDPs may be the polycyclic aromatic hydrocarbons and ''kerogen-like'' material that make up 70-08% of the carbonaceous matter in carbonaceous chondrites. C1 UNIV HOUSTON CLEAR LAKE, COLL SCI & TECHNOL, HOUSTON, TX 77058 USA. RP HARTMETZ, CP (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, PLANETARY SCI BRANCH, MAIL CODE SN2, HOUSTON, TX 77058 USA. NR 34 TC 2 Z9 2 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 USA SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 557 EP 567 PG 11 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300040 ER PT J AU RIETMEIJER, FJM NUTH, JA AF RIETMEIJER, FJM NUTH, JA TI TRIDYMITE AND MAGHEMITE FORMATION IN AN FE-SIO SMOKE SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID SILICATE; CONDENSATION; EXTINCTION AB The crystallographical, morphological and chemical properties of individual grains (2 nm up to 450 run in diameter) in a porous Fe-SiO smoke have been determined using analytical electron microscopy. This smoke was produced in a condensation flow apparatus in which nucleation of simple metal-oxide condensates occurs in the evolving vapor. During the initial stages of annealing, simple crystalline phases are produced. The condensation sequence begins with iron nucleation followed by heterogeneous nucleation of quenched mixed high-Fe silica grains (12-60 wt% FeO) that spinodally decompose and partially anneal to alpha-tridymite. With continued iron depletion, quenched pure silica grains form in the vapor, which are annealed to pure alpha-tridymite. Pure silica grains show widespread evidence for coalescence, which is consistent with higher surface energy for the pure silica phase compared to the nixed iron-silica grains. Large globules form via complete melting during coagulation and subsequently anneal to a mixture of chemically pure alpha- and beta-tridymite. Amorphous silica material continuously precipitates onto existing grains. The amorphous silica material enhaces sticking of grains and may be important to promote settling of grains in the evolving solar nebula. Magnetic maghemite (gamma-Fe2O3), which formed in the Fe-SiO vapor, may be important for Fe/Si fractionation in the evolving solar nebula and for polarization effects of dust extinctions in astrophysical environments. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP RIETMEIJER, FJM (reprint author), UNIV NEW MEXICO,DEPT GEOL,ALBUQUERQUE,NM 87131, USA. RI Nuth, Joseph/E-7085-2012 NR 32 TC 19 Z9 19 U1 0 U2 2 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 591 EP 599 PG 9 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300043 ER PT J AU FREY, HV DOUDNIKOFF, CE MONGEON, AM AF FREY, HV DOUDNIKOFF, CE MONGEON, AM TI ARE NOACHIAN-AGE RIDGED PLAINS (NPLR) ACTUALLY EARLY HESPERIAN IN AGE SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID TERRESTRIAL PLANETS; MARS; VOLCANISM AB Ridged plains volcanism has been an important resurfacing process in martian history. In addition to the well-known, globally distributed Early Hesperian (Hr) plains, there are apparently older, Noachian-age ridged plains (Nplr) that occur on Mars, often gradational with the younger units. The assignment of Noachian age is based on total crater counts, which is strongly influenced by a population of large craters that show through the Nplr ridged plains in Memnonia and Argyre. When analyzed using the Neukum and Hiller (1981) technique of breaking cumulative frequency curves into separate branches corresponding to separate resurfacing or depopulation on events, we find a strong branch with crater retention age N(1) = [ 25,000 +/- 3000] for both the Nplr ridged plains and the adjacent cratered terrain. This is identical to the Early Hesperian Lunae Planum Age (LPA) resurfacing by Hr ridged plains seen elsewhere on Mars. The craters that define this age surface are superimposed on the Nplr ridges; larger craters from older surfaces are nearly buried by the plains on which the ridges occur. We conclude that the ridged plains resurfacing in the Nplr terrains occurred in the Early Hesperian simultaneous with that in Lunae Planum, Coprates, Tempe Terra, and elsewhere on Mars. Our estimate of the thickness of these ridged plains in Argyre and Memnonia is <150 m and in some places <100 m, compared to 300-600 m in Lunae Planum. The thinness of the Nplr ridged plains material allows older surfaces to show through, leading to the apparent old age based on total crater counts. The more recent Early Hesperian age of the ridged plains in Noachian terrains, if common for other Nplr outcrops, has important implications for martian thermal and climate history. RP FREY, HV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. NR 30 TC 4 Z9 4 U1 0 U2 0 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 635 EP 644 PG 10 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300047 ER PT J AU GOLOMBEK, MP PLESCIA, JB FRANKLIN, BJ AF GOLOMBEK, MP PLESCIA, JB FRANKLIN, BJ TI FAULTING AND FOLDING IN THE FORMATION OF PLANETARY WRINKLE RIDGES SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Article ID MARE SERENITATIS; LUNAR; GRABENS; ORIGIN; SYRIA; MOON AB Topographic profiles across many lunar and across wrinkle ridges reveal a distinct elevation offset between one side of a ridge and the other. A simple explanation for this elevation offset is 2 fault beneath the ridge separating structural blocks at different elevations. Study of Earth analogs suggest die broad, low-relief physiography typical of wrinkle ridges is due to folding and faulting over thrust faults. In this interpretation, slip on a thrust fault dipping beneath the high side of a ridge produces the elevation offset; the complex thee morphology of a ridge results from near-surface splay faulting and folding. Although the dip of the thrust fault is not known, failure criteria and the observed angle of lunar and martian normal faults suggest a dip of about 25-degrees. Shortening due to folding at the surface is estimated by unfolding the surface profile of the ridge (assuming conservation of line length); shortening due to faulting is estimated from the relation between elevation offset and assumed fault dip. Total ridge shortening for this model appears to be on the order of 100 m; compressional strain is up to a few percent, compatible with previous estimates. Shortening due to faulting exceeds shortening due to folding for all fault dips assumed up to 60-degrees-80-degrees. This implies that faults beneath many wrinkle ridges break the surface to accommodate the greater displacement along the fault than is accommodated in the fold. RP GOLOMBEK, MP (reprint author), JET PROP LAB,MAIL STOP 183-501,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Plescia, Jeffrey/B-7738-2016 NR 48 TC 54 Z9 57 U1 0 U2 5 PU LUNAR AND PLANETARY INST PI HOUSTON PA 3600 BAY AREA BLVD, HOUSTON, TX 77058 SN 0270-9511 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 679 EP 693 PG 15 WC Geosciences, Multidisciplinary SC Geology GA MG413 UT WOS:A1991MG41300051 ER PT S AU PHINNEY, WC AF PHINNEY, WC BE Ryder, G Sharpton, VL TI LUNAR ANORTHOSITES, THEIR EQUILIBRIUM MELTS AND THE BULK MOON SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP PHINNEY, WC (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 0 TC 16 Z9 16 U1 0 U2 0 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 29 EP 49 PG 21 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00004 ER PT S AU JONES, JH WALKER, D AF JONES, JH WALKER, D BE Ryder, G Sharpton, VL TI THERMAL-DIFFUSION IN METAL-SULFIDE LIQUIDS - EARLY RESULTS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP JONES, JH (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 0 TC 4 Z9 4 U1 0 U2 1 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 367 EP 373 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00025 ER PT S AU HARTMETZ, CP GIBSON, EK BLANFORD, GE AF HARTMETZ, CP GIBSON, EK BLANFORD, GE BE Ryder, G Sharpton, VL TI IN-SITU EXTRACTION AND ANALYSIS OF VOLATILE ELEMENTS AND MOLECULES FROM CARBONACEOUS CHONDRITES SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP HARTMETZ, CP (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 527 EP 539 PG 13 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00037 ER PT S AU HARTMETZ, CP GIBSON, EK BLANFORD, GE AF HARTMETZ, CP GIBSON, EK BLANFORD, GE BE Ryder, G Sharpton, VL TI ANALYSIS OF VOLATILES PRESENT IN INTERPLANETARY DUST AND STRATOSPHERIC PARTICLES COLLECTED ON LARGE-AREA COLLECTORS SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP HARTMETZ, CP (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,MAIL CODE SN2,HOUSTON,TX 77058, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 557 EP 567 PG 11 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00040 ER PT S AU FREY, HV DOUDNIKOFF, CE MONGEON, AM AF FREY, HV DOUDNIKOFF, CE MONGEON, AM BE Ryder, G Sharpton, VL TI ARE NOACHIAN-AGE RIDGED PLAINS (NPLR) ACTUALLY EARLY HESPERIAN IN AGE SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP FREY, HV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 635 EP 644 PG 10 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00047 ER PT S AU GOLOMBEK, MP PLESCIA, JB FRANKLIN, BJ AF GOLOMBEK, MP PLESCIA, JB FRANKLIN, BJ BE Ryder, G Sharpton, VL TI FAULTING AND FOLDING IN THE FORMATION OF PLANETARY WRINKLE RIDGES SO PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE, VOL 21 SE PROCEEDINGS OF LUNAR AND PLANETARY SCIENCE LA English DT Proceedings Paper CT 21ST ANNUAL LUNAR AND PLANETARY SCIENCE CONF CY MAR 12-16, 1990 CL HOUSTON, TX SP LUNAR & PLANETARY INST, NASA, JOHNSON SPACE CTR, AMER ASSOC PETR GEOLOGISTS, AMER GEOPHY UNION, AMER ASTON SOC, DIV PLANETARY SCI, GEOL SOC AMER, INT UNION GEOL SCI, METEORIT SOC RP GOLOMBEK, MP (reprint author), JET PROP LAB,MAIL STOP 183-501,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Plescia, Jeffrey/B-7738-2016 NR 0 TC 54 Z9 57 U1 0 U2 5 PU LUNAR & PLANETARY INST PI HOUSTON PA HOUSTON SN 0270-9511 BN 0-942862-05-8 J9 P LUNAR PLANET SCI PY 1991 VL 21 BP 679 EP 693 PG 15 WC Geosciences, Multidisciplinary SC Geology GA BZ04M UT WOS:A1991BZ04M00051 ER PT J AU PINELLI, TE BARCLAY, RO GLASSMAN, N KENNEDY, JM DEMERATH, L AF PINELLI, TE BARCLAY, RO GLASSMAN, N KENNEDY, JM DEMERATH, L TI THE RELATIONSHIP BETWEEN 7 VARIABLES AND THE USE OF UNITED-STATES GOVERNMENT TECHNICAL REPORTS BY UNITED-STATES AEROSPACE ENGINEERS AND SCIENTISTS SO PROCEEDINGS OF THE ASIS ANNUAL MEETING LA English DT Article; Proceedings Paper CT 54TH ANNUAL MEETING OF THE AMERICAN SOC FOR INFORMATION SCIENCE ( ASIS 91 ) CY OCT 27-31, 1991 CL WASHINGTON, DC SP AMER SOC INFORMAT SCI AB A study was undertaken that investigated the relationship between the use of U.S. government technical reports by U.S. aerospace engineers and scientists and seven selected sociometric variables. Data were collected by means of a self-administered mail survey which was distributed to a randomly drawn sample of AIAA (American Institute of Aeronautics and Astronautics) members. Two research questions concerning the use of conference-meeting papers, journal articles, in-house technical reports, and U.S. government technical reports were investigated. Relevance, technical quality, and accessibility were found to be more important determinants of the overall extent to which U.S. government technical reports and the three other information products were used by U.S. aerospace engineers and scientists. C1 CONTINENTAL RES,NORFOLK,VA. INDIANA UNIV,BLOOMINGTON,IN 47401. RENSSELAER POLYTECH INST,TROY,NY 12181. RP PINELLI, TE (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 18 TC 2 Z9 2 U1 1 U2 2 PU INFORMATION TODAY INC PI MEDFORD PA 143 OLD MARLTON PIKE, MEDFORD, NJ 08055-8750 SN 0044-7870 J9 P ASIS ANNU MEET JI Proc. ASIS Annu. Meet. PY 1991 VL 28 BP 313 EP 321 PG 9 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA GP789 UT WOS:A1991GP78900040 ER PT J AU BUCHAN, RL AF BUCHAN, RL TI COMPUTER-AIDED INDEXING - A SURVEY SO PROCEEDINGS OF THE ASIS ANNUAL MEETING LA English DT Meeting Abstract C1 NASA,SCI & TECH INFORMAT FACIL,RMS ASSOCIATES,BALTIMORE,MD 21240. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INFORMATION TODAY INC PI MEDFORD PA 143 OLD MARLTON PIKE, MEDFORD, NJ 08055-8750 SN 0044-7870 J9 P ASIS ANNU MEET JI Proc. ASIS Annu. Meet. PY 1991 VL 28 BP 335 EP 335 PG 1 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA GP789 UT WOS:A1991GP78900056 ER PT J AU GENUARDI, MT AF GENUARDI, MT TI MACHINE INDEXING AND THESAURUS CONSTRUCTION FROM THE ANALYSIS OF NATURAL-LANGUAGE TEXT SO PROCEEDINGS OF THE ASIS ANNUAL MEETING LA English DT Meeting Abstract C1 NASA,SCI & TECH INFORMAT FACIL,RMS ASSOCIATES,BALTIMORE,MD 21240. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INFORMATION TODAY INC PI MEDFORD PA 143 OLD MARLTON PIKE, MEDFORD, NJ 08055-8750 SN 0044-7870 J9 P ASIS ANNU MEET JI Proc. ASIS Annu. Meet. PY 1991 VL 28 BP 335 EP 335 PG 1 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA GP789 UT WOS:A1991GP78900058 ER PT J AU HOLSTEGE, G AF HOLSTEGE, G TI DESCENDING MOTOR PATHWAYS AND THE SPINAL MOTOR SYSTEM - LIMBIC AND NONLIMBIC COMPONENTS SO PROGRESS IN BRAIN RESEARCH LA English DT Review ID BRAIN-STEM PROJECTIONS; NUCLEUS RAPHE MAGNUS; NICTITATING-MEMBRANE RESPONSE; HORSERADISH-PEROXIDASE METHOD; RETROGRADE AXONAL-TRANSPORT; NORTH-AMERICAN OPOSSUM; PONTINE RETICULAR-FORMATION; MUSCLE-SPINDLE AFFERENTS; CENTRAL NERVOUS-SYSTEM; SUBSTANCE-P-LIKE C1 UNIV CALIF SAN FRANCISCO, DEPT ANAT, SAN FRANCISCO, CA 94143 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 539 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0079-6123 J9 PROG BRAIN RES JI Prog. Brain Res. PY 1991 VL 87 BP 307 EP 421 PG 115 WC Neurosciences SC Neurosciences & Neurology GA HB641 UT WOS:A1991HB64100014 ER PT J AU PENN, BG CARDELINO, BH MOORE, CE SHIELDS, AW FRAZIER, DO AF PENN, BG CARDELINO, BH MOORE, CE SHIELDS, AW FRAZIER, DO TI GROWTH OF BULK SINGLE-CRYSTALS OF ORGANIC MATERIALS FOR NONLINEAR OPTICAL-DEVICES - AN OVERVIEW SO PROGRESS IN CRYSTAL GROWTH AND CHARACTERIZATION OF MATERIALS LA English DT Review ID SUBSTITUTED CONJUGATED MOLECULES; 2ND ORDER HYPERPOLARIZABILITY; 2ND-HARMONIC GENERATION; HARMONIC-GENERATION; CZOCHRALSKI TECHNIQUE; PERTURBATION-THEORY; META-NITROANILINE; DIPOLE-MOMENT; SUSCEPTIBILITIES; BENZENE AB Highly perfect single crystals of nonlinear optical organic materials are required for use in optical devices. An overview of the bulk crystal growth of these materials by melt, vapor, and solution processes is presented. Additionally, methods that may be used to purify starting materials, detect impurities at low levels, screen materials for crystal growth, and process grown crystals are discussed. C1 ATLANTA UNIV CTR INC, DOLPHUS E MILLIGAN SCI RES INST, ATLANTA, GA 30310 USA. SPELLMAN COLL, ATLANTA, GA 30314 USA. RP PENN, BG (reprint author), NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. NR 110 TC 41 Z9 41 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-8974 J9 PROG CRYST GROWTH CH JI Prog. Cryst. Growth Charact. Mater. PY 1991 VL 22 IS 1-2 BP 19 EP 51 DI 10.1016/0960-8974(91)90024-7 PG 33 WC Crystallography; Materials Science, Characterization & Testing SC Crystallography; Materials Science GA FE043 UT WOS:A1991FE04300002 ER PT J AU HERRON, JN HE, XM BALLARD, DW BLIER, PR PACE, PE BOTHWELL, ALM VOSS, EW EDMUNDSON, AB AF HERRON, JN HE, XM BALLARD, DW BLIER, PR PACE, PE BOTHWELL, ALM VOSS, EW EDMUNDSON, AB TI AN AUTOANTIBODY TO SINGLE-STRANDED-DNA - COMPARISON OF THE 3-DIMENSIONAL STRUCTURES OF THE UNLIGANDED FAB AND A DEOXYNUCLEOTIDE FAB COMPLEX SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE ANTI-SS-DNA AUTOANTIBODY; DEOXYNUCLEOTIDE FAB COMPLEX; CONFORMATIONAL CHANGES IN PROTEIN WHEN LIGAND IS BOUND ID INFLUENZA-VIRUS NEURAMINIDASE; ANTIBODY-ANTIGEN COMPLEX; NUCLEIC-ACIDS; HEAVY-CHAIN; SPECIFICITY; RECOGNITION; RESOLUTION; REFINEMENT; BINDING; SEQUENCES AB Crystal structures of the Fabs from an autoantibody (BV04-01) with specificity for single-stranded DNA have been determined in the presence and absence of a trinucleotide of deoxythymidylic acid, d(pT)3. Formation of the ligand-protein complex was accompanied by small adjustments in the orientations of the variable (V(L) and V(H)) domains. In addition, there were local conformational changes in the first hypervariable loop of the light chain and the third hypervariable loop of the heavy chain, which together with the domain shifts led to an improvement in the complementarity of nucleotide and Fab. The sugar-phosphate chain adopted an extended and "open" conformation, with the base, sugar, and phosphate components available for interactions with the protein. Nucleotide 1 (5'-end) was associated exclusively with the heavy chain, nucleotide 2 was shared by both heavy and light chains, and nucleotide 3 was bound by the light chain. The orientation of phosphate 1 was stabilized by hydrogen bonds with serine H52a and asparagine H53. Phosphate 2 formed an ion pair with arginine H52, but no other charge-charge interactions were observed. Insertion of the side chain of histidine L27d between nucleotides 2 and 3 resulted in a bend in the sugar-phosphate chain. The most dominant contacts with the protein involved the central thymine base, which was immobilized by cooperative stacking and hydrogen bonding interactions. This base was intercalated between a tryptophan ring (no. H100a) from the heavy chain and a tyrosine ring (no. L32) from the light chain. The resulting orientation of thymine was favorable for the simultaneous formation of two hydrogen bonds with the backbone carbonyl oxygen and the side chain hydroxyl group of serine L91 (the thymine atoms were the hydrogen on nitrogen 3 and keto oxygen 4). C1 HARRINGTON CANC CTR,1500 WALLACE BLVD,AMARILLO,TX 79106. UNIV ILLINOIS,DEPT MICROBIOL,URBANA,IL 61801. UNIV UTAH,DEPT PHARMACEUT,SALT LAKE CITY,UT 84108. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. YALE UNIV,SCH MED,IMMUNOBIOL SECT,NEW HAVEN,CT 06510. YALE UNIV,SCH MED,HOWARD HUGHES MED INST,NEW HAVEN,CT 06510. FU NCI NIH HHS [CA 19616]; NIAID NIH HHS [AI 22898, AI 20960] NR 52 TC 281 Z9 282 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-3585 J9 PROTEINS JI Proteins PY 1991 VL 11 IS 3 BP 159 EP 175 DI 10.1002/prot.340110302 PG 17 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA GM932 UT WOS:A1991GM93200001 PM 1749770 ER PT J AU HUTCHINGS, JB NEFF, SG AF HUTCHINGS, JB NEFF, SG TI 0.4-ARC-2ND IMAGES OF 3C-273 SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE QUASAR; HIGH-RESOLUTION IMAGES; STRUCTURE ID JET; DIFFERENCE; 3C273 AB We have obtained images in V and I bands of the QSO 3C 273 (1226+023) using the High-Resolution Camera of the Canada-France-Hawaii telescope. We discuss the structure and colors of the jet and details of the host galaxy, which have not been seen in previous observations. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP HUTCHINGS, JB (reprint author), NATL RES COUNCIL CANADA,DOMINION ASTROPHYS OBSERV,5071 W SAANICH RD,VICTORIA V8X 4M6,BC,CANADA. NR 12 TC 10 Z9 10 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 1991 VL 103 IS 659 BP 26 EP 31 DI 10.1086/132791 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EY250 UT WOS:A1991EY25000003 ER PT J AU KALER, JB SHAW, RA FEIBELMAN, WA IMHOFF, CL AF KALER, JB SHAW, RA FEIBELMAN, WA IMHOFF, CL TI PB-6 AND ITS CENTRAL STAR SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article DE PLANETARY NEBULA; O-IV EMISSION STAR; ELEMENTAL ABUNDANCES ID STRUCTURE FORBIDDEN TRANSITIONS; EFFECTIVE COLLISION STRENGTHS; SOUTHERN PLANETARY-NEBULAE; INTERMEDIATE-MASS STARS; GASEOUS NEBULAE; ULTRAVIOLET-SPECTRA; 3P3 CONFIGURATION; EVOLUTION; LINES; ABUNDANCES AB We find the hot nucleus (V = 16.9, T(z) = 103,000 K) of the Type I southern planetary nebula PB 6 to be a member of the rare class of O VI stars. The blended O VI lambda-3811 + lambda-3834 emission doublet is among the strongest seen with an equivalent width (relative to the stellar continuum) of about 400 angstrom. A distance between 4400 and 6400 pc from the Shklovsky method gives a luminosity between 3700 and 7800 L. and a core mass between 0.59 and 0.64 M.. There is some evidence for local dust that dims the star relative to the nebula. We confirm Torres-Peimbert and Peimbert's measurement of very high nebular He/H ( = 0.18). From ultraviolet (IUE) and optical measurements we also confirm a high N/O ratio (about 1.1) and, in addition, find a very high C/O, perhaps as large as 3. The helium, nitrogen, and carbon abundances are all very high for the core mass and the relations found by Kaler and Jacoby. The Ne/O ratio, at 0.17, is close to the norm found for planetaries, which supports the high O/H, and the S/O is roughly solar. Ar/O is about double solar, but the ionic abundances do not fit the ionic distribution of the other elements, suggesting that there may be problems with the atomic data. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. COMP SCI CORP,LANHAM,MD 20706. RP KALER, JB (reprint author), UNIV ILLINOIS,DEPT ASTRON,1002 W GREEN,URBANA,IL 61801, USA. NR 57 TC 23 Z9 23 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 1991 VL 103 IS 659 BP 67 EP 78 DI 10.1086/132796 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EY250 UT WOS:A1991EY25000008 ER PT J AU LANGEL, RA AF LANGEL, RA TI INTERNATIONAL GEOMAGNETIC REFERENCE FIELD, 1991 REVISION - INTERNATIONAL-ASSOCIATION-OF-GEOMAGNETISM-AND-AERONOMY (IAGA) DIVISION-V, WORKING GROUP-8 - ANALYSIS OF THE MAIN FIELD AND SECULAR VARIATION SO PURE AND APPLIED GEOPHYSICS LA English DT Article RP LANGEL, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GEODYNAM BRANCH CODE 921,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU BIRKHAUSER VERLAG AG PI BASEL PA PO BOX 133 KLOSTERBERG 23, CH-4010 BASEL, SWITZERLAND SN 0033-4553 J9 PURE APPL GEOPHYS JI Pure Appl. Geophys. PY 1991 VL 137 IS 3 BP 301 EP 308 DI 10.1007/BF00876994 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HW107 UT WOS:A1991HW10700008 ER PT J AU MANNEY, GL AF MANNEY, GL TI ON THE DEPENDENCE OF TRAVELING-WAVE STABILITY ON BASIC STATE WAVE PHASE SPEED SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article ID BAROTROPIC INSTABILITY; ZONAL FLOWS; STRATOSPHERE AB The dependence of stability on basic state wave phase speed is examined in a nondivergent barotropic model on a sphere for planetary scale waves with phase speeds typical of waves observed in the atmosphere. Triad interactions are examined analytically and compared to numerical results from a full spectral model. A number of traids may result in growth of the perturbation components for each basic state wave; for each triad there is a basic state wave phase speed where it is resonant, identified as the point where the critical amplitude for instability to that perturbation becomes zero. Critical amplitudes for instability obtained using the full spectral model generally agree well with triad results. Since the basic state wave phase speed determines which triad will grow, spatial structure and critical amplitudes for instability for the growing disturbances depend strongly on basic state wave phase speed. The results of this idealized study suggest that phase speed may be an important factor in determining the stability of planetary scale waves in the atmosphere. RP MANNEY, GL (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JAN PY 1991 VL 117 IS 498 BP 319 EP 331 PN B PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FU771 UT WOS:A1991FU77100003 ER PT J AU SCHATTEN, KH AF SCHATTEN, KH TI SELF FIELD ELECTROMAGNETISM AND QUANTUM PHENOMENA SO RADIATION EFFECTS AND DEFECTS IN SOLIDS LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL CONF ON COHERENT RADIATION PROCESSES IN STRONG FIELDS CY JUN 18-22, 1990 CL CATHOLIC UNIV AMER, WASHINGTON, DC SP CATHOLIC UNIV AMER, USN, NAVAL RES LAB, USN, OFF NAVAL RES HO CATHOLIC UNIV AMER ID ZERO-POINT RADIATION; ELECTRODYNAMICS; MECHANICS; VACUUM RP SCHATTEN, KH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,SOLAR RADIAT OFF,GREENBELT,MD 20771, USA. NR 32 TC 1 Z9 1 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 1042-0150 J9 RADIAT EFF DEFECT S JI Radiat. Eff. Defects Solids PY 1991 VL 122 BP 233 EP 273 DI 10.1080/10420159108220507 PN 1 PG 41 WC Nuclear Science & Technology; Physics, Fluids & Plasmas; Physics, Condensed Matter SC Nuclear Science & Technology; Physics GA HN188 UT WOS:A1991HN18800013 ER PT J AU HARDING, AK AF HARDING, AK TI RADIATIVE PROCESSES IN STRONG MAGNETIC-FIELDS SO RADIATION EFFECTS AND DEFECTS IN SOLIDS LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL CONF ON COHERENT RADIATION PROCESSES IN STRONG FIELDS CY JUN 18-22, 1990 CL CATHOLIC UNIV AMER, WASHINGTON, DC HO CATHOLIC UNIV AMER ID GAMMA-RAY BURSTS; RELATIVISTIC PLASMAS; COMPTON-SCATTERING; PAIR ANNIHILATION; SYNCHROTRON RADIATION; THOMSON SCATTERING; ONE-PHOTON; CYCLOTRON; ABSORPTION; EMISSION RP HARDING, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Harding, Alice/D-3160-2012 NR 52 TC 0 Z9 0 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 1042-0150 J9 RADIAT EFF DEFECT S JI Radiat. Eff. Defects Solids PY 1991 VL 122 BP 625 EP 641 DI 10.1080/10420159108211495 PN 2 PG 17 WC Nuclear Science & Technology; Physics, Fluids & Plasmas; Physics, Condensed Matter SC Nuclear Science & Technology; Physics GA HN193 UT WOS:A1991HN19300012 ER PT J AU VANDERSANDE, JW FARMER, J AF VANDERSANDE, JW FARMER, J TI NEUTRON-IRRADIATION DAMAGE IN SIGE ALLOYS SO RADIATION EFFECTS AND DEFECTS IN SOLIDS LA English DT Article DE NEUTRON; SIGE; DAMAGE; ANNEALING RP VANDERSANDE, JW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 6 TC 1 Z9 1 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 1042-0150 J9 RADIAT EFF DEFECT S JI Radiat. Eff. Defects Solids PY 1991 VL 118 IS 2 BP 125 EP 130 DI 10.1080/10420159108220627 PG 6 WC Nuclear Science & Technology; Physics, Fluids & Plasmas; Physics, Condensed Matter SC Nuclear Science & Technology; Physics GA HC070 UT WOS:A1991HC07000005 ER PT B AU KIM, SS LIANG, RH AF KIM, SS LIANG, RH BE CLOUGH, RL SHALABY, SW TI EFFECTS OF ULTRAVIOLET AND VACUUM ULTRAVIOLET-IRRADIATION ON FLUORINATED ETHYLENE PROPYLENE COPOLYMERS - AN ELECTRON-PARAMAGNETIC RESONANCE STUDY SO RADIATION EFFECTS ON POLYMERS SE ACS SYMPOSIUM SERIES LA English DT Review CT SYMP AT THE 200TH NATIONAL MEETING OF THE AMERICAN CHEMICAL SOC : RADIATION EFFECTS ON POLYMERS CY AUG 26-31, 1990 CL WASHINGTON, DC SP AMER CHEM SOC RP KIM, SS (reprint author), CALTECH,JET PROP LAB,SPACE MAT SCI & TECHNOL SECT,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA WASHINGTON BN 0-8412-2165-0 J9 ACS SYM SER PY 1991 VL 475 BP 135 EP 145 PG 11 WC Physics, Atomic, Molecular & Chemical; Polymer Science SC Physics; Polymer Science GA BU84P UT WOS:A1991BU84P00009 ER PT J AU RODRIGUEZ, E AF RODRIGUEZ, E TI BEYOND THE KIRCHHOFF APPROXIMATION-II ELECTROMAGNETIC SCATTERING SO RADIO SCIENCE LA English DT Article ID PHASE-PERTURBATION TECHNIQUE; RANDOM ROUGH SURFACES; WAVES AB In a previous paper the momentum transfer expansion was introduced for scalar wave scattering. It was shown that, using this expansion, one could obtain wavelength dependent curvature corrections to the Kirchhoff approximation. In this paper we extend the momentum transfer perturbation expansion to electromagnetic waves. Curvature corrections to the surface current are obtained. Using these results, the specular field and the backscatter cross section are calculated. RP RODRIGUEZ, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE,PASADENA,CA 91109, USA. NR 12 TC 22 Z9 23 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN-FEB PY 1991 VL 26 IS 1 BP 121 EP 132 DI 10.1029/90RS01863 PG 12 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA EY834 UT WOS:A1991EY83400011 ER PT J AU BUTLER, RW SJOGREN, JA AF BUTLER, RW SJOGREN, JA TI FORMAL DESIGN VERIFICATION OF DIGITAL CIRCUITRY SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Article AB This paper examines a methodology for hardware verification developed by RSRE (Royal Signals and Radar Establishment) in the context of the SRI International's EHDM (Enhanced Hierarchical Design Methodology) specification/verification system. The methodology utilizes a four-level specification hierarchy with the following levels: functional level, finite automata model, block model, and circuit level. The properties of a level are proved as theorems in the level below it. In this paper, this methodology is applied to a N-bit counter/multiplexer circuit and is critically examined. The specifications are written in EHDM's specification language, Extended Special, and the proofs are performed using the EHDM theorem prover. Recommendations are made for improving both the RSRE methodology and the EHDM system. RP BUTLER, RW (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 130,HAMPTON,VA 23665, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PY 1991 VL 32 IS 1-2 BP 67 EP 93 DI 10.1016/0951-8320(91)90048-C PG 27 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA EW825 UT WOS:A1991EW82500005 ER PT J AU FINELLI, GB AF FINELLI, GB TI NASA SOFTWARE FAILURE CHARACTERIZATION EXPERIMENTS SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Article AB A series of experiments are being conducted by NASA to generate data on which to base the development of credible methods for assessing the reliability of software targeted for flight-critical applications. Two sets of experiments designed to characterize software failure processes have been conducted by different research groups. The results of these experiments were consistent: errors caused by different faults in a program occurred at widely varying rates; program failure rates exhibited a log-linear trend with respect to the number of faults corrected; some faults were found to interact in either concealing or revealing ways; and contiguous regions of the input space which cause a program to generate errors, called error crystals, were found and characterized for some faults in some programs. Collectively, these experiments have produced information on software failure which must be accounted for in software reliability modeling approaches. A current experiment is being conducted to investigate the occurrence of similar and new behaviors in real-time control software and assess the effectiveness of software development and testing methods. The application under study is the guidance and control software for a planetary landing vehicle. RP FINELLI, GB (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 19 TC 29 Z9 30 U1 1 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PY 1991 VL 32 IS 1-2 BP 155 EP 169 DI 10.1016/0951-8320(91)90052-9 PG 15 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA EW825 UT WOS:A1991EW82500009 ER PT J AU HALL, FG STREBEL, DE NICKESON, JE GOETZ, SJ AF HALL, FG STREBEL, DE NICKESON, JE GOETZ, SJ TI RADIOMETRIC RECTIFICATION - TOWARD A COMMON RADIOMETRIC RESPONSE AMONG MULTIDATE, MULTISENSOR IMAGES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID LANDSAT MSS DATA; REFLECTANCE AB A common radiometric response is required for quantitative analysis of multiple satellite images of a scene acquired on different dates with different sensors. We describe a technique to "radiometrically rectify" multiple Landsat images of a scene to a reference image, and evaluate it using a pair of Landsat 5 images acquired 2 years apart. All rectified images should appear as if they were acquired with the same sensor, while observing through the atmospheric and illumination conditions of the reference image. If atmospheric optical depth and sensor calibration data are available for the reference image, then an atmospheric correction algorithm may be used to correct all the rectified images to absolute surface reflectance. The "radiometric rectification" algorithm identifies "radiometric control sets," i.e., sets of scene landscape elements with a mean reflectance which is expected to change little with time. The average digital count values of these radiometric control sets are used to calculate linear transforms relating digital count values between images. We evaluate the technique empirically with a pair of Landsat 5 TM images of a scene for which surface reflectance and atmospheric optical depth data are available. We also examine its performance under a wide range of atmospheric conditions using simulations based on atmospheric models. We find that the radiometric rectification algorithm performed well for the visible and near infrared bands, adjusting surface reflectance for the effects of relative atmospheric differences to within 1%. The performance is not as good for the midinfrared bands on TM. There are several possible causes for this; we could not determine which was the most important. We conclude from these studies that for scenes containing reflectance stable elements, radiometric rectification should be a useful alternative to atmospheric radiative transfer codes and sensor calibration approaches when reliable atmospheric optical depth data or calibration coefficients are not available. When atmospheric optical data and sensor calibration information are available for one of a sequence of radiometrically rectified images, an atmospheric radiative transfer code may be used to correct each image in the sequence to absolute surface reflectance. C1 VERSAR INC,SPRINGFIELD,VA. ST SYST CORP,LANHAM,MD. RP HALL, FG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 923,GREENBELT,MD 20771, USA. RI Goetz, Scott/A-3393-2015 OI Goetz, Scott/0000-0002-6326-4308 NR 34 TC 369 Z9 388 U1 0 U2 39 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN PY 1991 VL 35 IS 1 BP 11 EP 27 DI 10.1016/0034-4257(91)90062-B PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FJ250 UT WOS:A1991FJ25000002 ER PT J AU CURRAN, PJ DUNGAN, JL MACLER, BA PLUMMER, SE AF CURRAN, PJ DUNGAN, JL MACLER, BA PLUMMER, SE TI THE EFFECT OF A RED LEAF PIGMENT ON THE RELATIONSHIP BETWEEN RED EDGE AND CHLOROPHYLL CONCENTRATION SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID WHEAT CANOPIES; VEGETATION; SHIFT AB The point of maximum slope in a reflectance spectrum of vegetation occurs at the boundary between red and near infrared wavelengths and is known as the "red edge." There is a strong relationship between the red edge and the chlorophyll concentration of leaves and canopies. The aim of this research was to determine the effect of a second leaf pigment, red amaranthin, on the relationship between red edge and chlorophyll concentration. The red edge, chlorophyll concentration, and amaranthin concentration were recorded for 163 amaranth leaves in the laboratory. Experimental treatments with nitrate and salts caused a very concentration (0-20 mg / g), and amaranthin concentration (0-0.47 mg / g). There was a near-linear relationship between red edge and chlorophyll concentration for leaves with low amaranthin concentration (< 0.075 mg / g). This relationship was strongest for leaves from vegetative plants and was similar in form to that observed for a canopy. By contrast the red edge was at longer wavelengths and independent of chlorophyll concentration for leaves with high amaranthin concentration (> 0.075 mg / g), as a result of the strong absorption of visible light by amaranthin and the resultant movement of the red / near infrared boundary to longer wavelengths at higher amaranthin concentrations. This is the first reported study on the effect of a second leaf pigment on the relationship between red edge and chlorophyll concentration. The results suggest that the presence of a second leaf pigment would limit the use of a remotely sensed red edge for the estimation of chlorophyll concentration. C1 NASA,AMES RES CTR,TGS TECHNOL INC,MOFFETT FIELD,CA 94035. US EPA,DRINKING WATER BRANCH W-6-1,SAN FRANCISCO,CA. BRITISH NATL SPACE CTR,MONKS WOOD EXPT STN,REMOTE SENSING APPLICAT DEV UNIT,HUNTINGDON,CAMBS,ENGLAND. RP CURRAN, PJ (reprint author), UNIV COLL SWANSEA,DEPT GEOG,SINGLETON PK,SWANSEA SA2 8PP,W GLAM,WALES. RI Dungan, Jennifer/G-9921-2016 OI Dungan, Jennifer/0000-0002-4863-1616 NR 41 TC 131 Z9 142 U1 2 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN PY 1991 VL 35 IS 1 BP 69 EP 76 DI 10.1016/0034-4257(91)90066-F PG 8 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA FJ250 UT WOS:A1991FJ25000006 ER PT J AU NOEVER, DA AF NOEVER, DA TI A ROTATING SPECTROMETER FOR SEPARATION CONCENTRATION OF BIOCONVECTING MICROORGANISMS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB The rotating spectrometer is discussed as a method to separate and concentrate microorganisms in free solution. Following focusing in a rotated frame, the separation is accomplished using different radial dependencies of concentrated algal and protozoan species. The focusing itself appears as concentric rings and arises from the coupling between swimming direction and Coriolis forces. A dense cut is taken at varying radii and extraction is replenished at an inlet. Unlike standard separation and concentrating techniques, the rotating method requires active organism participation and, in principle, can split different morphologies and swimming behaviors for the large class of organisms known to bioconvect. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ES-76,HUNTSVILLE,AL 35812, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JAN PY 1991 VL 62 IS 1 BP 229 EP 232 DI 10.1063/1.1142312 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EQ607 UT WOS:A1991EQ60700035 ER PT J AU COLOMBO, OL WATKINS, MM AF COLOMBO, OL WATKINS, MM TI SATELLITE POSITIONING SO REVIEWS OF GEOPHYSICS LA English DT Review ID PHASE AMBIGUITY RESOLUTION; CASA UNO EXPERIMENT; ORBIT DETERMINATION; CRUSTAL DEFORMATION; GEODETIC BASELINES; TRACKING NETWORK; SOUTH-AMERICA; SYSTEM; PRECISION; CALIFORNIA AB The last four years have brought major changes to the practice of space geodesy, the most remarkable being the proliferation of precise techniques using the Global Positioning System to locate both points fixed to the Earth's surface and on moving vehicles. In their most accurate applications, GPS methods compare increasingly well with satellite laser ranging when measuring baselines of up to 1000 km. Meanwhile, the performance of laser systems has continued to improve, and the steady operation of laser sites around the world has extended the span of recorded observations to nearly one and a half decades of very high quality data. C1 UNIV TEXAS,CTR SPACE RES,AUSTIN,TX 78712. RP COLOMBO, OL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV MARYLAND ASTRON PROGRAM,GREENBELT,MD 20771, USA. NR 170 TC 0 Z9 0 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 138 EP 147 PN 1 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX961 UT WOS:A1991FX96100020 ER PT J AU RAY, JR AF RAY, JR TI RADIO INTERFEROMETRY SO REVIEWS OF GEOPHYSICS LA English DT Review ID BASE-LINE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; PLATE MOTIONS; GEODETIC BASELINES; MARK-III; LONG; VLBI; DEFORMATION; EARTHQUAKE; TECTONICS RP RAY, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INTERFEROMETR INC,CODE 9269,GREENBELT,MD 20771, USA. NR 164 TC 4 Z9 4 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 148 EP 156 PN 1 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX961 UT WOS:A1991FX96100021 ER PT J AU SCHENK, PM AF SCHENK, PM TI OUTER PLANET SATELLITES SO REVIEWS OF GEOPHYSICS LA English DT Review ID PLUTO-CHARON SYSTEM; DISK-INTEGRATED PHOTOMETRY; GEYSER-LIKE PLUMES; 1ST UV SPECTRUM; ICY SATELLITES; URANIAN SATELLITES; INTERNAL STRUCTURE; GALILEAN SATELLITES; WATER ICE; VISCOELASTIC MODELS RP SCHENK, PM (reprint author), CALTECH,JET PROP LAB,MS 230-225,PASADENA,CA 91109, USA. NR 206 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 297 EP 305 PN 1 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX961 UT WOS:A1991FX96100040 ER PT J AU KAHN, R APPLEBY, J AF KAHN, R APPLEBY, J TI PLANETARY-ATMOSPHERES SO REVIEWS OF GEOPHYSICS LA English DT Review ID GREAT RED SPOT; SOUTH POLAR-CAP; CLOUD PHOTOPOLARIMETER IMAGES; LINE TRANSFER CALCULATIONS; GENERAL-CIRCULATION MODEL; DOUBLING THIN-LAYERS; PLUTO-CHARON SYSTEM; OUTER SOLAR-SYSTEM; UREY PRIZE LECTURE; HIGH-RESOLUTION RP KAHN, R (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 311 TC 0 Z9 0 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 328 EP 337 PN 1 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX961 UT WOS:A1991FX96100043 ER PT J AU PHILLIPS, JD REYNOLDS, RL FREY, H AF PHILLIPS, JD REYNOLDS, RL FREY, H TI CRUSTAL STRUCTURE INTERPRETED FROM MAGNETIC-ANOMALIES SO REVIEWS OF GEOPHYSICS LA English DT Review ID CHEMICAL REMANENT MAGNETIZATION; ARBITRARY 3-DIMENSIONAL BODIES; SOUTHEASTERN UNITED-STATES; JURASSIC PREUSS SANDSTONE; COCORP DEEP REFLECTION; CEMENT OIL-FIELD; MOUNT-ST-HELENS; TECTONIC EVOLUTION; AEROMAGNETIC DATA; MAGSAT DATA C1 US GEOL SURVEY,DENVER,CO 80225. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP PHILLIPS, JD (reprint author), US GEOL SURVEY,927 NATL CTR,RESTON,VA 22092, USA. NR 216 TC 2 Z9 2 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 416 EP 427 PN 1 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX961 UT WOS:A1991FX96100053 ER PT J AU ROBERTS, DA GOLDSTEIN, ML AF ROBERTS, DA GOLDSTEIN, ML TI TURBULENCE AND WAVES IN THE SOLAR-WIND SO REVIEWS OF GEOPHYSICS LA English DT Review ID COMET GIACOBINI-ZINNER; INTERPLANETARY MAGNETIC-FIELD; STEEPENED MAGNETOSONIC WAVES; AMPLITUDE ALFVEN WAVES; WATER GROUP IONS; FREQUENCY ELECTROMAGNETIC-WAVES; SPHERICAL-SHELL DISTRIBUTION; LARGE-SCALE FLUCTUATIONS; PICK-UP IONS; STRONG HYDROMAGNETIC TURBULENCE RP ROBERTS, DA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,INTERPLANETARY BRANCH,CODE 692,GREENBELT,MD 20771, USA. RI Roberts, Dana/D-4625-2012; Goldstein, Melvyn/B-1724-2008 NR 220 TC 50 Z9 50 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 932 EP 943 PN 2 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX962 UT WOS:A1991FX96200047 ER PT J AU GAZIS, PR AF GAZIS, PR TI PHYSICS OF THE OUTER HELIOSPHERE SO REVIEWS OF GEOPHYSICS LA English DT Review ID INTERPLANETARY MAGNETIC-FIELD; LOCAL INTERSTELLAR-MEDIUM; LARGE-SCALE FLUCTUATIONS; MODIFIED STELLAR WINDS; COSMIC-RAY GRADIENTS; LYMAN ALPHA FLUX; SOLAR-WIND; PICKUP IONS; PERTURBATION APPROACH; MERIDIONAL TRANSPORT RP GAZIS, PR (reprint author), NASA,AMES RES CTR,SAN JOSE STATE UNIV FDN,MOFFETT FIELD,CA 94035, USA. NR 119 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 955 EP 961 PN 2 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX962 UT WOS:A1991FX96200049 ER PT J AU MOORE, TE AF MOORE, TE TI ORIGINS OF MAGNETOSPHERIC PLASMA SO REVIEWS OF GEOPHYSICS LA English DT Review ID LATITUDE BOUNDARY-LAYER; TRANSVERSE ION ENERGIZATION; MAGNETIC-FIELD MODELS; FLUX-TRANSFER EVENTS; TIME RING CURRENT; POLAR WIND; ELECTRIC-FIELDS; AURORAL-ZONE; ACCELERATION MECHANISM; SATELLITE-OBSERVATIONS AB A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the Earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved our ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. New computing capabilities have likewise improved our ability to plausibly model the magnetosphere so that new interpretative hypotheses may be tested. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the "geopause." It is now well established that the an infusion of ionospheric O+ plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. This role is often dominant in the larger storms. Smaller quantities of particles with high charge states and very energetic ionospheric molecules are observed as well. However, after more than two decades of observation and debate, the question remains: Are magnetospheric protons of solar or terrestrial origin? RP MOORE, TE (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 161 TC 49 Z9 54 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PY 1991 VL 29 SU S BP 1039 EP 1048 PN 2 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA FX962 UT WOS:A1991FX96200058 ER PT J AU WEISBIN, C PERILLARD, D AF WEISBIN, C PERILLARD, D TI JET PROPULSION LABORATORY ROBOTIC FACILITIES AND ASSOCIATED RESEARCH SO ROBOTICA LA English DT Article DE PROFILE; JPL; TELEROBOTICS; RESEARCH AB This paper describes the robotics facilities and associated research program of the Jet Propulsion Laboratory, lead center in telerobotics for the United States National Aeronautics and Space Administration. Emphasis is placed on evolution from teleoperation to remote system automation. Research is described in manipulator modelling and control, real-time planning and monitoring, navigation in outdoor terrain, real-time sensing and perception, human-machine interface, and overall system architectures. Applications to NASA missions emphasize robotic spacecraft for solar system exploration, satellite servicing and retrieval, assembly of structures, and surveillance. Applications to military missions include battlefield navigation, surveillance, logistics, command and control. RP WEISBIN, C (reprint author), CALTECH,JET PROP LAB,ROBOT & AUTOMAT SYST SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0263-5747 J9 ROBOTICA JI Robotica PD JAN-MAR PY 1991 VL 9 BP 7 EP 21 PN 1 PG 15 WC Robotics SC Robotics GA EY826 UT WOS:A1991EY82600009 ER PT J AU PANG, KD AF PANG, KD TI THE LEGACIES OF ERUPTION - MATCHING TRACES OF ANCIENT VOLCANISM WITH CHRONICLES OF COLD AND FAMINE SO SCIENCES-NEW YORK LA English DT Article RP PANG, KD (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 9 Z9 9 U1 0 U2 1 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 E 63RD ST, NEW YORK, NY 10021 SN 0036-861X J9 SCIENCES JI Sci.-New York PD JAN-FEB PY 1991 VL 31 IS 1 BP 30 EP 35 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EM868 UT WOS:A1991EM86800019 ER EF