FN Thomson Reuters Web of Science™ VR 1.0 PT J AU SMITH, JG CONNELL, JW HERGENROTHER, PM AF SMITH, JG CONNELL, JW HERGENROTHER, PM TI SYNTHESIS AND PROPERTIES OF POLY[ARYLENE ETHER (N-ARYLENE BENZIMIDAZOLE)]S SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 63 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300063 ER PT J AU CONNELL, JW CROALL, CI HERGENROTHER, PM AF CONNELL, JW CROALL, CI HERGENROTHER, PM TI CHEMISTRY AND PROPERTIES OF POLYIMIDES CONTAINING BENZHYDROL GROUPS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 64 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300064 ER PT J AU STEPHENS, JM GLASGOW, MB KIEFER, RL ORWOLL, RA LONG, SAT AF STEPHENS, JM GLASGOW, MB KIEFER, RL ORWOLL, RA LONG, SAT TI RADIATION EFFECTS ON FILMS OF BORON-LOADED POLYMERS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 COLL WILLIAM & MARY,DEPT CHEM,WILLIAMSBURG,VA 23185. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 90 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300090 ER PT J AU DURAJ, SA ECKLES, WE FANWICK, PE ANDRAS, MT HEPP, AF AF DURAJ, SA ECKLES, WE FANWICK, PE ANDRAS, MT HEPP, AF TI MONONUCLEAR AND BINUCLEAR INDIUM AND GALLIUM COMPOUNDS WITH NITROGEN AND SULFUR-CONTAINING LIGANDS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CLEVELAND STATE UNIV,DEPT CHEM,CLEVELAND,OH 44115. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. NASA,LEWIS RES CTR,PHOTOVOLTAIC BRANCH,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 98 EP INOR PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK162 UT WOS:A1992HK16200508 ER PT J AU DEUR, JM KUNDU, KP AF DEUR, JM KUNDU, KP TI A SIMPLIFIED REACTION-MECHANISM FOR PROPANE COMBUSTION SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,BROOK PK,OH. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 120 EP FUEL PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16102462 ER PT J AU HERGENROTHER, PM AF HERGENROTHER, PM TI COMPOSITES FOR HIGH-SPEED COMMERCIAL TRANSPORTS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. BOEING CO,COMMERCIAL AIRPLANE GRP,SEATTLE,WA 98124. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 133 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300133 ER PT J AU SUMMONS, RE JAHNKE, LL AF SUMMONS, RE JAHNKE, LL TI METHYLOTROPHIC BACTERIA - BIOMARKER LIPIDS AND THEIR C-ISOTOPIC COMPOSITIONS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 BUR MINERAL RESOURCES,CANBERRA 2601,AUSTRALIA. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 135 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16102605 ER PT J AU EFTEKHARI, A STCLAIR, AK STOAKLEY, DM KUPPA, S SINGH, JJ AF EFTEKHARI, A STCLAIR, AK STOAKLEY, DM KUPPA, S SINGH, JJ TI MICROSTRUCTURAL CHARACTERIZATION OF THIN POLYIMIDE FILMS BY POSITRON LIFETIME SPECTROSCOPY SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 139 EP PMSE PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300761 ER PT J AU SUTTER, JK WATERS, JF SCHUERMAN, MA AF SUTTER, JK WATERS, JF SCHUERMAN, MA TI N-CYCAP POLYIMIDE MATRIX RESINS IN HIGH-TEMPERATURE ENVIRONMENTS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 139 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300139 ER PT J AU SUMMERS, DP AF SUMMERS, DP TI REDUCTION OF NITRITE IN THE EARLY ARCHEAN OCEAN - IMPLICATIONS FOR THE EVOLUTION OF LIFE SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 149 EP GEOC PN 1 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK161 UT WOS:A1992HK16102619 ER PT J AU HERGENROTHER, PM SMITH, JG CONNELL, JW AF HERGENROTHER, PM SMITH, JG CONNELL, JW TI MECHANICAL-PROPERTIES OF A POLY(ARYLENE ETHER BENZIMIDAZOLE) SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 257 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300253 ER PT J AU JAFFE, RL KOMORNICKI, A MATSUDA, T SCHEINER, AC YOON, DY MCLEAN, AD AF JAFFE, RL KOMORNICKI, A MATSUDA, T SCHEINER, AC YOON, DY MCLEAN, AD TI ABINITIO COMPUTATIONS FOR THE MODELING OF AROMATIC POLYMERS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95120. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. POLYATOM RES INST,MT VIEW,CA 94043. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 295 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300291 ER PT J AU SMITH, GD LUDOVICE, PJ JAFFE, RL YOON, DY AF SMITH, GD LUDOVICE, PJ JAFFE, RL YOON, DY TI MOLECULAR-DYNAMICS SIMULATION OF PVC MELTS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95114. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. ELORET INST,SUNNYVALE,CA. POLYGEN CORP,WALTHAM,MA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 307 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300302 ER PT J AU KIM, SS YAVROUIAN, AH LIANG, RH AF KIM, SS YAVROUIAN, AH LIANG, RH TI SEGMENTAL MOBILITY AND FREE-VOLUME DECAY OF POLY(PHENYL METHACRYLATE) - AN EPR STUDY SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 341 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300333 ER PT J AU TAWA, GJ MIELKE, SL FRIEDMAN, RS HALVICK, P TRUHLAR, DG AF TAWA, GJ MIELKE, SL FRIEDMAN, RS HALVICK, P TRUHLAR, DG TI QUANTUM DYNAMICS OF NA(32P)+H2 COLLISIONS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV MINNESOTA,USA,HIGH PERFORMANCE COMP RES CTR,MINNEAPOLIS,MN 55455. UNIV MINNESOTA,DEPT CHEM,PSYCHOPHYSIOL PROGRAM,INST SUPERCOMP,MINNEAPOLIS,MN 55455. RI Mielke, Steven/B-7533-2008; Truhlar, Donald/G-7076-2015 OI Mielke, Steven/0000-0002-1938-7503; Truhlar, Donald/0000-0002-7742-7294 NR 1 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 347 EP PHYS PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK162 UT WOS:A1992HK16202443 ER PT J AU BRYANT, RG JENSEN, BJ HERGENROTHER, PM AF BRYANT, RG JENSEN, BJ HERGENROTHER, PM TI SYNTHESIS AND PROPERTIES OF PHENYLETHYNYL-TERMINATED ARYLENE ETHERS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 482 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300473 ER PT J AU JENSEN, BJ HERGENROTHER, PM NWOKOGU, G AF JENSEN, BJ HERGENROTHER, PM NWOKOGU, G TI POLYIMIDES WITH PENDENT ETHYNYL GROUPS SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. HAMPTON INST,HAMPTON,VA 23668. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 484 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300475 ER PT J AU ALSTON, WB AF ALSTON, WB TI STRUCTURE-TO-PROPERTY RELATIONSHIPS IN ADDITION CURED POLYMERS .4. CORRELATIONS BETWEEN THERMOOXIDATIVE WEIGHT LOSSES OF NORBORNENYL CURED POLYIMIDE RESINS AND THEIR COMPOSITES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,USA,AVIAT RES & TECHNOL ACT,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 503 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300493 ER PT J AU CHUANG, KC VANNUCCI, RD AF CHUANG, KC VANNUCCI, RD TI EFFECTS OF A NONCOPLANAR BIPHENYLENEDIAMINE ON PROCESSING AND PROPERTIES OF ADDITION POLYIMIDES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 506 EP POLY PN 3 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK163 UT WOS:A1992HK16300496 ER PT J AU ANDRAS, MT HEPP, AF FANWICK, PE DURAJ, SA BODNAR, MM AF ANDRAS, MT HEPP, AF FANWICK, PE DURAJ, SA BODNAR, MM TI STRUCTURAL AND SPECTROSCOPIC PROPERTIES OF TRINUCLEAR OXO-CENTERED GALLIUM(III) CARBOXYLATES SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NASA,LEWIS RES CTR,PHOTOVOLTA BRANCH,CLEVELAND,OH 44135. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. CLEVELAND STATE UNIV,DEPT CHEM,CLEVELAND,OH 44115. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 5 PY 1992 VL 203 BP 530 EP INOR PN 2 PG 0 WC Chemistry, Multidisciplinary SC Chemistry GA HK162 UT WOS:A1992HK16200939 ER PT J AU KAISER, ML DESCH, MD FARRELL, WM MACDOWALL, RJ STONE, RG LECACHEUX, A PEDERSEN, BM ZARKA, P AF KAISER, ML DESCH, MD FARRELL, WM MACDOWALL, RJ STONE, RG LECACHEUX, A PEDERSEN, BM ZARKA, P TI ULYSSES OBSERVATIONS OF ESCAPING VLF EMISSIONS FROM JUPITER SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VOYAGER AB The Ulysses URAP experiment has detected Jovian radio emissions in the VLF range at distances from Jupiter in excess of 1.5 A.U. The URAP observations represent the first synoptic observations of Jupiter in the VLF band, 3 to 30 kHz. In this band lie the low-frequency extent of the bKOM emission, the escaping continuum emission, and the Jovian type IIIs. Initial results indicate that the continuum varies in frequency with the solar wind ram pressure at Jupiter, whereas, the Jovian type IIIs appear to be controlled to some extent by the planetary rotation, often appearing when system III longitude 100-degrees faces the spacecraft. C1 OBSERV PARIS,DASOP,F-92195 MEUDON,FRANCE. RP KAISER, ML (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. RI MacDowall, Robert/D-2773-2012; Farrell, William/I-4865-2013 NR 14 TC 21 Z9 21 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 3 PY 1992 VL 19 IS 7 BP 649 EP 652 DI 10.1029/92GL00387 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HM703 UT WOS:A1992HM70300004 ER PT J AU FARRELL, WM DESCH, MD AF FARRELL, WM DESCH, MD TI CLOUD-TO-STRATOSPHERE LIGHTING DISCHARGES - A RADIO-EMISSION MODEL SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIGHTNING RETURN STROKE; WHISTLERS; RADIATION AB Recent observations of rare cloud-to-stratospheric lightning discharges suggest the events are inherently "slow-rising", with the emitted energy reaching peak values in about 10 milliseconds. Applying a dipole radiation model, we demonstrate that the emitted radio wave energy from such slow-rising events is strongest below about 50 Hz, and possesses a significant rolloff at higher frequencies. In the analysis, various current distributions are considered in order to determine the effect on the radio spectrum. Near 10 kHz, the emission from cloud-to-stratospheric lightning is significantly reduced as compared to the typical cloud-to-ground return stroke, with amplitudes as much as 50 dB lower. This result may explain the lack of detection of VLF signals from recently observed long-lasting discharge events. RP FARRELL, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXPTL PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 18 TC 20 Z9 20 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 3 PY 1992 VL 19 IS 7 BP 665 EP 668 DI 10.1029/91GL02955 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HM703 UT WOS:A1992HM70300008 ER PT J AU HUANG, NE LONG, SR TUNG, CC DONELAN, MA YUAN, YL LAI, RJ AF HUANG, NE LONG, SR TUNG, CC DONELAN, MA YUAN, YL LAI, RJ TI THE LOCAL PROPERTIES OF OCEAN SURFACE-WAVES BY THE PHASE-TIME METHOD SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Traditionally, investigation of statistical properties of ocean waves has been limited largely to global quantities related to elevation and amplitude such as the power spectral and various probability density functions. Although these properties give valuable information about the wave field, the results cannot be related directly to any portion of the time data from which it was derived. We present a new approach using phase information to view and study the properties of frequency modulation, wave group structures, and wave breaking. We apply the method here to ocean wave time series data and identify a new type of wave group (containing the large "rogue" waves), but the method also has the capability of broad applications in the analysis of time series data in general. C1 NATL WATER RES INST BRANCH,CANADA CTR INLAND WATERS,BURLINGTON L7R 4A6,ONTARIO,CANADA. MINERALS MANAGEMENT SERV,ST HERNDON,VA 22070. NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. N CAROLINA STATE UNIV,DEPT CIVIL ENGN,RALEIGH,NC 27695. CHINESE OCEANOG BUR,RES INST 1,QINGDAO,PEOPLES R CHINA. RP HUANG, NE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Long, Steven/D-7248-2012 NR 8 TC 29 Z9 30 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 3 PY 1992 VL 19 IS 7 BP 685 EP 688 DI 10.1029/92GL00670 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HM703 UT WOS:A1992HM70300013 ER PT J AU BERATAN, DN BETTS, JN ONUCHIC, JN AF BERATAN, DN BETTS, JN ONUCHIC, JN TI TUNNELING PATHWAY AND REDOX-STATE-DEPENDENT ELECTRONIC COUPLINGS AT NEARLY FIXED DISTANCE IN ELECTRON-TRANSFER PROTEINS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article; Proceedings Paper CT ROCHESTER SYMP ON CHARGE TRANSFER IN RESTRICTED GEOMETRICS CY JUL 10-13, 1991 CL UNIV ROCHESTER, CTR PHOTOINDUCED CHARGE TRANSFER, ROCHESTER, NY SP NATL SCI FDN, USN, OFF NAVAL RES, UNIV ROCHESTER, EASTMAN KODAK, XEROX HO UNIV ROCHESTER, CTR PHOTOINDUCED CHARGE TRANSFER ID CYTOCHROME-C; BIOLOGICAL MOLECULES; PLASTOCYANINS AB The tunneling pathway model for electron transfer, which accounts for the unique covalent, hydrogen-bonded, and van der Waals contacts linking donor and acceptor in a protein, gives a consistent description of electron-transfer rates in ruthenated proteins (cytochrome c, myoglobin, and cytochrome b5), while simpler exponential decay models are not fully adequate. We report several new testable predictions of the pathway model relating electron-transfer rates to protein structure. The analysis predicts qualitative differences in the distance dependence of protein electron transfer at short (< 5 angstrom) vs long distance, differences in the nature of the coupling through alpha-helix vs beta-sheet, and the possibility of switching electronic coupling upon oxidation/reduction or ligation/deligation in metalloproteins. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,BECKMAN INST,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. RI Beratan, David/C-5098-2011 NR 37 TC 125 Z9 125 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 2 PY 1992 VL 96 IS 7 BP 2852 EP 2855 DI 10.1021/j100186a014 PG 4 WC Chemistry, Physical SC Chemistry GA HM372 UT WOS:A1992HM37200015 ER PT J AU FINN, TT AF FINN, TT TI WHY HAVE PEOPLE IN SPACE SO AEROSPACE AMERICA LA English DT Article RP FINN, TT (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD APR PY 1992 VL 30 IS 4 BP B68 EP B68 PG 1 WC Engineering, Aerospace SC Engineering GA HN003 UT WOS:A1992HN00300013 ER PT J AU KNIGHT, DD HORSTMAN, CC BOGDONOFF, S AF KNIGHT, DD HORSTMAN, CC BOGDONOFF, S TI STRUCTURE OF SUPERSONIC TURBULENT-FLOW PAST A SWEPT COMPRESSION CORNER SO AIAA JOURNAL LA English DT Article ID BOUNDARY-LAYER INTERACTIONS; SHARP FIN; MODEL; EQUATIONS AB The structure of the shock wave/turbulent boundary-layer interaction generated by a three-dimensional swept compression corner has been investigated through a combined experimental and theoretical research program. The flowfield geometry is defined by the streamwise compression angle-alpha and the sweep angle-lambda of the corner. The present study examines two different configurations, namely, (alpha, lambda) = (24 deg, 40 deg) and (24 deg, 60 deg) at Mach 3 and Re(delta)(infinity) almost-equal-to 9 x 10(5). The theoretical model is the three-dimensional Reynolds-averaged compressible Navier-Stokes equations with turbulence incorporated using a turbulent eddy viscosity. Four different turbulence models (Baldwin-Lomax, Cebeci-Smith, Jones-Launder with wall functions, and Jones-Launder integrated to the wall) were employed. The calculated flowfields display general agreement with experimental data for surface pressure and good agreement with experimental flowfield profiles of pitot pressure and yaw angle. The principal feature of the flowfield is a large vortical structure approximately aligned with the corner. The entrainment of incoming fluid into the vortical structure is strongly affected by the sweep angle lambda. Viscous (turbulent and molecular) effects appear to be important only in the immediate vicinity of the surface and in an isolated region within the interaction and near the corner. C1 PRINCETON UNIV,DEPT AEROSP & MECH ENGN,PRINCETON,NJ 08544. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP KNIGHT, DD (reprint author), RUTGERS STATE UNIV,DEPT MECH & AEROSP ENGN,NEW BRUNSWICK,NJ 08903, USA. NR 26 TC 6 Z9 6 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 APR PY 1992 VL 30 IS 4 BP 890 EP 896 DI 10.2514/3.11006 PG 7 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100005 ER PT J AU BARNWELL, RW AF BARNWELL, RW TI NONADIABATIC AND 3-DIMENSIONAL EFFECTS IN COMPRESSIBLE TURBULENT BOUNDARY-LAYERS SO AIAA JOURNAL LA English DT Article ID DEFECT STREAM FUNCTION; WALL-WAKE METHOD; LAW AB A defect stream function formulation for nonadiabatic flow with small crossflow is developed. The first-integral property of this formulation provides for the removal of the streamline curvature term in the governing equation so that the form of the reduced equation for small crossflow is the same as that for two-dimensional flow. The combined law of the wall and wake is used in place of the no-slip boundary condition. A three-dimensional law-of-the-wall formulation is used to develop a closed-form solution for the crossflow angle near the wall. Analytic solutions for nonadiabatic, compressible, equilibrium flow with a Clauser outer-region eddy-viscosity model are obtained, and excellent agreement with experimental skin friction and velocity profile data for nonadiabatic, compressible flat-plate flow is achieved. An analytic solution for a linear inner-region eddy-viscosity model is also obtained; the wake function part of this solution is found to be inconsistent with the empirically established law of the wake. All comparisons with experiment are for two-dimensional equilibrium flow. RP BARNWELL, RW (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 23 TC 2 Z9 2 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 APR PY 1992 VL 30 IS 4 BP 897 EP 904 DI 10.2514/3.11007 PG 8 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100006 ER PT J AU HAMMOND, SW BARTH, TJ AF HAMMOND, SW BARTH, TJ TI EFFICIENT MASSIVELY PARALLEL EULER SOLVER FOR 2-DIMENSIONAL UNSTRUCTURED GRIDS SO AIAA JOURNAL LA English DT Article AB We describe a data parallel mesh-vertex upwind finite-volume scheme for solving the Euler equations on triangular unstructured meshes. A novel vertex-based partitioning of the problem is introduced that minimizes the computation and communication costs associated with distributing the computation to the processors of a massively parallel computer. Finally, we compare the performance of this unstructured computation on 8K processors of the Connection Machine CM-2 with one processor of a Cray-YMP. Our experiments show that 8K processors of the CM-2 achieve 86% of the performance of one processor of the Cray-YMP on the unstructured mesh computations described here. C1 RENSSELAER POLYTECH INST,COMP SCI,TROY,NY 12181. NASA,AMES RES CTR,COMPUTAT FLUID DYNAM BRANCH,MOFFETT FIELD,CA 94035. RP HAMMOND, SW (reprint author), NASA,AMES RES CTR,ADV COMP SCI RES INST,MAIL STOP T045-1,MOFFETT FIELD,CA 94035, USA. NR 11 TC 8 Z9 10 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 1992 VL 30 IS 4 BP 947 EP 952 DI 10.2514/3.11013 PG 6 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100012 ER PT J AU HARVEY, AD ACHARYA, S LAWRENCE, SL AF HARVEY, AD ACHARYA, S LAWRENCE, SL TI SOLUTION-ADAPTIVE GRID PROCEDURE FOR THE PARABOLIZED NAVIER-STOKES EQUATIONS SO AIAA JOURNAL LA English DT Article AB A solution-adaptive grid procedure based on an error equidistribution principle is developed and applied to a three-dimensional parabolized Navier-Stokes solver. The scheme redistributes grid points line by line in both crossflow directions, with grid point motion controlled by forces analogous to tensional and torsional spring forces. The tensional force is proportional to the error measure or a weighting function related to the error measure. The torsional force is used to control grid skewness relative to the upstream and cross-stream coordinate lines. Weighting functions are selected by first normalizing flowfield gradients and/or curvature of a number of dependent variables and then selecting the largest at each point. The hypersonic flow over a right-circular cone at three different yaw angles is studied to demonstrate the performance of the solution-adaptive grid procedure. Pitot pressure profiles and surface pressure computed using the solution-adaptive algorithm are compared with experimental results as well as with numerical results obtained using a fixed grid. Pitot pressure predictions using the adaptive grid algorithm show better agreement with experiment than those obtained using a fixed grid. C1 DOW CHEM CO USA,RES & DEV,MIDLAND,MI. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP HARVEY, AD (reprint author), LOUISIANA STATE UNIV,MECH ENGN,BATON ROUGE,LA 70803, USA. NR 14 TC 3 Z9 3 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 APR PY 1992 VL 30 IS 4 BP 953 EP 962 DI 10.2514/3.11014 PG 10 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100013 ER PT J AU BANDYOPADHYAY, PR RIESTER, JE ASH, RL AF BANDYOPADHYAY, PR RIESTER, JE ASH, RL TI HELICAL-PERTURBATION DEVICE FOR CYLINDER-WING VORTEX GENERATORS SO AIAA JOURNAL LA English DT Article ID TRAILING LINE VORTEX; STABILITY; BREAKDOWN; FLOW; JET AB A new device has been developed for introducing helical perturbations by means of low-level fluid injection into the cylinder boundary layer of a flow-aligned cylinder-wing vortex generator. Its basic characteristics have been analyzed and experimentally evaluated at moderate Reynolds numbers. When the cylinder boundary layer is tripped and there is no strong swirl, then in the near wake, the device lowers the mean rate of drop of the Strouhal number with Reynolds number by one-half. In the nearly nonexpanding and swirling far wake, both signs of input perturbations, namely co- and counter-rotating with the vortex, are detectable in the vortex core only confirming a wave-guide-like behavior. In the narrow frequency range of 80-100 Hz, these input perturbations slightly amplify downstream when counterrotating but attenuate in the corotating case. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23508. NR 18 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 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 1992 VL 30 IS 4 BP 988 EP 992 DI 10.2514/3.11018 PG 5 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100017 ER PT J AU PARK, C YOON, S AF PARK, C YOON, S TI CALCULATION OF REAL-GAS EFFECTS ON BLUNT-BODY TRIM ANGLES SO AIAA JOURNAL LA English DT Article AB The effect of vibrational excitation and dissociation at high temperatures on the trim angle of attack of a blunt lifting body is calculated for a nonequilibrium flow regime in air using a computational fluid dynamics technique. Air is considered to consist of five neutral species, O, N, NO, O2, and N2, and both one- and two-temperature thermochemical nonequilibrium models are used in determining the thermodynamic state. A computer code, named CENS2H (Compressible Euler-Navier-Stokes Two-dimensional Hypersonic), is developed by incorporating this model into an existing perfect-gas code named CENS2D, which uses a lower-upper factorization based on the symmetric Gauss-Seidel sweeping technique. The code is applied to compute the forebody flow of a two-dimensional blunt body of the shape of the Apollo Command Module at a finite angle of attack. The results show that the trim angle of attack is smaller for a reacting gas than for a perfect gas. The calculated shift in the trim angle due to the real-gas effect is of the same order as that seen during the Apollo flights. The one-temperature nonequilibrium model yields the same trim angles as the two-temperature model, but the constant-gamma (= C(p)/C(v)) solution that reproduces the shock standoff distance fails to reproduce the trim angle. C1 MCAT INST,MOFFETT FIELD,CA 94035. RP PARK, C (reprint author), NASA,AMES RES CTR,EXPTL AEROTHERMODYNAM SECT,MOFFETT FIELD,CA 94035, USA. NR 29 TC 13 Z9 16 U1 2 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 1992 VL 30 IS 4 BP 999 EP 1007 DI 10.2514/3.11020 PG 9 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100019 ER PT J AU FENNO, CC STREETT, CL HASSAN, HA AF FENNO, CC STREETT, CL HASSAN, HA TI USE OF FINITE VOLUME SCHEMES FOR TRANSITION SIMULATION SO AIAA JOURNAL LA English DT Note ID BOUNDARY-LAYER-TRANSITION C1 NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,DIV FLUID DYNAM,HAMPTON,VA 23665. RP FENNO, CC (reprint author), N CAROLINA STATE UNIV,MECH & AEROSP ENGN,RALEIGH,NC 27695, USA. NR 12 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 0001-1452 J9 AIAA J JI AIAA J. PD APR PY 1992 VL 30 IS 4 BP 1122 EP 1125 DI 10.2514/3.11036 PG 4 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100035 ER PT J AU OBAYASHI, S AF OBAYASHI, S TI FREESTREAM CAPTURING FOR MOVING COORDINATES IN 3 DIMENSIONS SO AIAA JOURNAL LA English DT Note ID CONSERVATION C1 MCAT INST,SAN JOSE,CA 95127. RP OBAYASHI, S (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 9 TC 27 Z9 28 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 APR PY 1992 VL 30 IS 4 BP 1125 EP 1128 DI 10.2514/3.11037 PG 4 WC Engineering, Aerospace SC Engineering GA HM681 UT WOS:A1992HM68100036 ER PT J AU RASHIDNIA, N BALASUBRAMANIAM, R DELSIGNORE, D AF RASHIDNIA, N BALASUBRAMANIAM, R DELSIGNORE, D TI INTERFACIAL-TENSION MEASUREMENT OF IMMISCIBLE LIQUIDS USING A CAPILLARY-TUBE SO AICHE JOURNAL LA English DT Note C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. UNIV TOLEDO,DEPT MECH ENGN,TOLEDO,OH 43606. RP RASHIDNIA, N (reprint author), SVERDRUP TECHNOL INC,BROOK PK,OH 44142, USA. NR 9 TC 26 Z9 26 U1 0 U2 3 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD APR PY 1992 VL 38 IS 4 BP 615 EP 618 DI 10.1002/aic.690380416 PG 4 WC Engineering, Chemical SC Engineering GA HP469 UT WOS:A1992HP46900015 ER PT J AU BREININGER, DR SMITH, RB AF BREININGER, DR SMITH, RB TI RELATIONSHIPS BETWEEN FIRE AND BIRD DENSITY IN COASTAL SCRUB AND SLASH PINE FLATWOODS IN FLORIDA SO AMERICAN MIDLAND NATURALIST LA English DT Article AB Bird densities within coastal scrub and slash pine flatwoods were compared with time since fire, mean shrub height, number of snags and percent burn. Most shrub-dwelling birds preferred older stands (> 10 yr since last fire) with taller shrubs, or intermediate stands (4 yr since last fire) than recently burned stands (1-2 yr since last fire). Five species were negatively correlated with percent burn in stands burned 1-2 yr previously. The downy woodpecker was most abundant in recently burned areas. Densities of three species of woodpeckers and the northern bobwhite were positively correlated with snag density. The results suggest that extensive burns occurring every 4 yr or less are likely to have a negative influence on shrub-dwelling birds that are a natural component of these coastal communities. RP BREININGER, DR (reprint author), NASA,BIONET CORP,BIOMED OPERAT & RES OFF,MAIL CODE BIO-2,KENNEDY SPACE CTR,FL 32899, USA. NR 37 TC 7 Z9 7 U1 0 U2 4 PU AMER MIDLAND NATURALIST PI NOTRE DAME PA UNIV NOTRE DAME, BOX 369, ROOM 295 GLSC, NOTRE DAME, IN 46556 SN 0003-0031 J9 AM MIDL NAT JI Am. Midl. Nat. PD APR PY 1992 VL 127 IS 2 BP 233 EP 240 DI 10.2307/2426529 PG 8 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA HP079 UT WOS:A1992HP07900003 ER PT J AU SOCKI, RA KARLSSON, HR GIBSON, EK AF SOCKI, RA KARLSSON, HR GIBSON, EK TI EXTRACTION TECHNIQUE FOR THE DETERMINATION OF O-18 IN WATER USING PREEVACUATED GLASS VIALS SO ANALYTICAL CHEMISTRY LA English DT Note C1 TEXAS TECH UNIV,DEPT GEOSCI,LUBBOCK,TX 79409. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP SOCKI, RA (reprint author), LOCKHEED ESC,C-23,2400 NASA RD,HOUSTON,TX 77058, USA. NR 11 TC 126 Z9 129 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 1 PY 1992 VL 64 IS 7 BP 829 EP 831 DI 10.1021/ac00031a026 PG 3 WC Chemistry, Analytical SC Chemistry GA HL044 UT WOS:A1992HL04400026 PM 11536503 ER PT J AU EGAN, WG ISRAEL, S JOHNSON, WR WHITEHEAD, VS AF EGAN, WG ISRAEL, S JOHNSON, WR WHITEHEAD, VS TI HIGH-RESOLUTION SPACE-SHUTTLE POLARIMETRY FOR FARM CROP CLASSIFICATION SO APPLIED OPTICS LA English DT Article DE POLARIZATION; SATELLITE IMAGERY; FARM CROP CLASSIFICATION; ATMOSPHERE ID POLARIZATION AB A significant advance is reported in imaging the polarimetry of a terrestrial area of Earth located along the Mississippi River near New Madrid, Missouri. Color imagery was obtained with twin Hasselblad cameras with mutually perpendicular polarization analyzers. Digitization of the imagery in three colors (red, green, and blue) was accomplished at the Johnson Space Center Video Digital Analysis System Laboratory, Houston, Texas. A ground resolution of 80-90 m was achieved in the high-resolution imagery. Percent polarization was superior to photometry for recognition and characterization of farm crops such as rice, milo, cotton, and soybeans and of fallow areas. Statistical analyses of the percent-polarization data permit a unique classification of crops. Atmospheric effects may be deduced. Space-shuttle window distortion and viewing angle-sun geometry must be taken into account in analyzing the data. C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 25 TC 6 Z9 6 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 1 PY 1992 VL 31 IS 10 BP 1542 EP 1548 PG 7 WC Optics SC Optics GA HM110 UT WOS:A1992HM11000024 PM 20720788 ER PT J AU SCHOMBERT, JM BOTHUN, GD SCHNEIDER, SE MCGAUGH, SS AF SCHOMBERT, JM BOTHUN, GD SCHNEIDER, SE MCGAUGH, SS TI A CATALOG OF LOW SURFACE BRIGHTNESS GALAXIES - LIST-II SO ASTRONOMICAL JOURNAL LA English DT Article ID STAR-FORMATION; DISK GALAXIES; ABSORPTION; REDSHIFT; MORPHOLOGY; DISCOVERY; EVOLUTION; CLUSTER; DWARF AB The second edition of a catalog of low surface brightness (LSB) galaxies is presented based on a visual search of the Second Palomar Sky Survey. This paper presents newly discovered LSB galaxies in 97 fields within the declination range of O-degrees to +25-degrees. The primary catalog (objects with diameters greater than 1 arcmin) contains 198 objects; the secondary catalog (30 arcsec < D < 1 arcmin) contains 140 objects. H I observations are presented for 171 of these newly discovered galaxies. Our 80% detection rate yields a fairly representative velocity distribution for a sample of LSB objects. The sample is dominated by LSB disks galaxies with 2000 < v < 9000 km s-1. Below 2000 km s-1 a few true dwarf galaxies are found. Approximately 10% of the sample has v > 10 000 km s-1 and thus represents additional examples of truly large LSB galaxies. The H I redshift distribution is consistent with the hypothesis that LSB and HSB disk galaxies, in general, are drawn from the same distribution of physical size (e.g., disk scale length) modulo the curious tendency for the LSB sample to contain significantly more large-scale length galaxies which rival the prototype, Malin 1. Optical broadband and H-alpha imaging for a subset of the catalog is also presented confirming their quiescent nature. Our survey using the PSS-II is presently 35% complete and indicates that the UGC is 11.5% incomplete for a 1 mag arcsec-2 increase in surface brightness depth. Overall this survey demonstrates that LSB galaxies are not exclusively dwarf galaxies but encompass all Hubble types, although dominated by the late types, and all masses. C1 UNIV OREGON,DEPT PHYS,EUGENE,OR 97403. UNIV MASSACHUSETTS,DEPT PHYS & ASTRON,AMHERST,MA 01002. UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. RP SCHOMBERT, JM (reprint author), CALTECH,JET PROP LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91125, USA. NR 36 TC 160 Z9 160 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 APR PY 1992 VL 103 IS 4 BP 1107 EP 1133 DI 10.1086/116129 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK359 UT WOS:A1992HK35900008 ER PT J AU GAUTIER, TN BOULANGER, F PERAULT, M PUGET, JL AF GAUTIER, TN BOULANGER, F PERAULT, M PUGET, JL TI A CALCULATION OF CONFUSION NOISE DUE TO INFRARED CIRRUS SO ASTRONOMICAL JOURNAL LA English DT Article ID EMISSION; DENSITY; GALAXY AB General expressions are developed for the statistical errors to be expected in photometric measurements due to confusion in a background of fluctuating surface brightness. Backgrounds actually observed in the far infrared by the IRAS satellite are used to calculate tables of these error expressions for two simple measurement techniques. The confusion noise limited sensitivities for NASA's planned Space Infrared Telescope Facility and the European Space Agency's Infrared Space Observatory are estimated at a wavelength of 100-mu-m from these tables. C1 ECOLE NORM SUPER,RADIO ASTRON,F-75231 PARIS 05,FRANCE. UNIV PARIS 11,INST ASTROPHYS,F-91405 ORSAY,FRANCE. RP GAUTIER, TN (reprint author), CALTECH,JET PROP LAB,CTR INFRARED PROC & ANAL,MS 100-22,PASADENA,CA 91125, USA. NR 14 TC 162 Z9 162 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 APR PY 1992 VL 103 IS 4 BP 1313 EP 1324 DI 10.1086/116144 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK359 UT WOS:A1992HK35900023 ER PT J AU GARCIA, MR GRINDLAY, JE BAILYN, CD PIPHER, JL SHURE, MA WOODWARD, CE AF GARCIA, MR GRINDLAY, JE BAILYN, CD PIPHER, JL SHURE, MA WOODWARD, CE TI THE INFRARED COUNTERPART OF GX-13+1 SO ASTRONOMICAL JOURNAL LA English DT Article ID X-RAY SOURCES; X-1; VARIABILITY; SCATTERING; CYGNUS-X-3; EMISSION; BINARIES; SEARCH; HALOS; STAR AB We have discovered a bright (K = 12) infrared source which is likely the counterpart to the bright galactic bulge x-ray source GX 13 + 1. Observations with the MMT infrared photometer and the Rochester infrared Array camera at the IRTF allow determination of the source position to approximately 0.7 arcsec, allow the infrared colors to be measured, and shows no variability on a 1 yr timescale. We consider four possible sources for the infrared emission, and conclude that it is most likely due to a K giant secondary. Future observations should allow more definite discrimination between the various possibilities. The discovery of a late-type giant secondary in GX 13 + 1 is contrary to the expectation that low-mass x-ray binaries (LMXB) which show quasiperiodic oscillations (QPO) have giant companions, while those which do not show QPO (like GX 13 + 1) have dwarf secondaries. The relation between the size of the scattered x-ray halo and the A(V) inferred from the infrared observations is compared to that found in other x-ray sources. C1 YALE UNIV,DEPT ASTRON,NEW HAVEN,CT 06511. UNIV ROCHESTER,DEPT PHYS & ASTRON,ROCHESTER,NY 14627. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. UNIV WYOMING,WYOMING INFRARED OBSERV,LARAMIE,WY 82071. UNIV HAWAII,NASA,INFRARED TELESCOPE FACIL,HONOLULU,HI 96822. RP GARCIA, MR (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138, USA. NR 44 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 APR PY 1992 VL 103 IS 4 BP 1325 EP 1329 DI 10.1086/116145 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK359 UT WOS:A1992HK35900024 ER PT J AU MARCIALIS, RL LEBOFSKY, LA DISANTI, MA FINK, U TEDESCO, EF AFRICANO, J AF MARCIALIS, RL LEBOFSKY, LA DISANTI, MA FINK, U TEDESCO, EF AFRICANO, J TI THE ALBEDOS OF PLUTO AND CHARON - WAVELENGTH DEPENDENCE SO ASTRONOMICAL JOURNAL LA English DT Article ID PHOTOMETRY; ATMOSPHERE; CALIBRATION; OCCULTATION AB The 1987 March 03 occultation of Charon by Pluto was monitored simultaneously with three telescopes in the vicinity of Tucson, Arizona. Each site covered a distinct wavelength interval, with the total range spanning 0.44-2.4-mu-m. Observing the same event ensures an identical Sun-Pluto-Earth geometry for all three sites, and minimizes the assumptions which must be made to combine results. We have used this spectrophotometry to derive the individual geometric albedos of Pluto and Charon over a factor of greater-than-or-equal-to 5 in wavelength. Combining our results with those of Binzel [Science, 241, 1070 (1988)], we obtain improved (B - V) color estimates (on the "Johnson Pluto" system) for the components of the system at rotational phase 0.75: (Pluto + Charon) = 0.843 +/- 0.006; Pluto alone = 0.866 +/- 0.007; and Charon alone = 0.702 +/- 0.010. C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. ASSOC UNIV RES ASTRON INC,KITT PEAK NATL OBSERV,TUCSON,AZ 85726. RP MARCIALIS, RL (reprint author), CALTECH,JET PROP LAB,MS 183-501,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 26 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 0004-6256 J9 ASTRON J JI Astron. J. PD APR PY 1992 VL 103 IS 4 BP 1389 EP 1394 DI 10.1086/116153 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK359 UT WOS:A1992HK35900032 ER PT J AU PEREZ, MR WEBB, JR THE, PS AF PEREZ, MR WEBB, JR THE, PS TI THE VARIABLE HERBIG-AE STAR HR-5999 .10. ITS PHOTOMETRIC PULSE-SHAPED VARIABILITY SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE PRE-MAIN SEQUENCE; HERBIG AE/BE STARS; PHOTOMETRY ID MAIN-SEQUENCE STARS; SHELL; LINES AB We present additional photometric observations (Stromgren y filter) of the Herbig Ae Star HR 5999. This new set of data, composed of 282 data points covering April 1983 to August 1989, was used in conjunction with the 362 data points recently compiled by Baade and Stahl (1989). Our aim was to detect single or multiple periods in the integrated set of data spanning nearly 20 years. Through the use of series analysis techniques, and by removing any linear component present in the raw data, we were able to detect weak peaks in the power spectra (in the order of intensity the strongest peaks are at 301 and 113 days) which were not self evident in the phase diagrams. The overall picture of the data shows a small linear component, which is more noticeable in the new set of data, indicating that the recent maxima appear brighter. By a detailed analysis of the full light curve we were able to detect the presence of well-defined "pulses" or bursts. Further Gaussian fits of these bursts indicated that the pulses are relatively rapid, of the order of 10 days, with some of them being closely spaced. No periodicity was found for the pulses. A possible explanation of these aperiodic outbursts is that they detect a flow of matter accompanied by magnetic field disturbances originated from the interior of the star, unlike those originating externally such a binary perturbations, which tend to be periodic. C1 FLORIDA INT UNIV, DEPT PHYS, MIAMI, FL 33199 USA. UNIV AMSTERDAM, ASTRON INST ANTON PANNEKOEK, 1098 SJ AMSTERDAM, NETHERLANDS. RP PEREZ, MR (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CSC IUE OBSERV, CODE 6849, GREENBELT, MD 20771 USA. NR 32 TC 22 Z9 22 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 APR PY 1992 VL 257 IS 1 BP 209 EP 217 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM106 UT WOS:A1992HM10600021 ER PT J AU DEWINTER, D PEREZ, MR HU, JY THE, PS AF DEWINTER, D PEREZ, MR HU, JY THE, PS TI A STUDY OF THE OPTICAL AND ULTRAVIOLET SPECTRAL CHARACTERISTICS AND OF THE CIRCUMSTELLAR MATERIAL AROUND THE NEW LUMINOUS BLUE VARIABLE WRA-751 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE EARLY-TYPE STARS; EMISSION LINES; INFRARED EXCESS; SUPERGIANT; LUMINOSITY; EVOLUTIONARY STATE; UV RADIATION ID AG-CAR; CARINAE; STARS; DUST AB In this paper the LBV characteristics of the new LBV-candidate WRA 751 (= He 3-591), suggested by Hu et al. (1990), are studied in more detail. For this purpose we have made a comparison with observational characteristics of the well-known LBVs AG Car and HR Car using photometric (visual, near- and far-IR) and spectroscopic (optical) data of Hu et al. (1990), supplemented with an IUE spectrum (2500-3100 angstrom) and direct CCD images in H-alpha, blue and red. From the spectroscopic comparison we found: (a) That the spectra of WRA 751 and HR Car, discussed in this paper, are similar to the minimum-phase spectrum of AG Car and, therefore, resemble the Of/WN 9 spectral type, (b) That from the characteristics of the optical, near- and far-UV (IUE) spectra the Fe II spectrum in these wavelength regions is due to continuum fluorescence, (c) That the H, He I, Fe II and [Fe II] emission lines are formed in different parts of the stars' envelopes, corresponding to their expanding velocities. From the comparison of the photometric data and direct imagery we further found strong similarities concerning the circumstellar material of the studied LBVs: (d) A weak near-IR excess, which is caused by free-free emission of a low velocity stellar wind (v less-than-or-equal-to 500 km s-1, and beta = 0.5), connected with a high mass loss rate (-4.5 < log M < -6.0M. yr-1), and possibly a small contribution due to ionized gas contained in a circumstellar nebular region. The relative low mass loss rates of WRA 751 and HR Car, compared to those of LBVs at maximum phase, indicate that these stars are in a phase of quiescence (Lamers 1989). (e) A far-IR excess due to thermal radiation of a dust shell of 130-170 K which lie between 0.1-0.4 pc from the central star. (f) The existence of a spherical nebular region around WRA 751, is seen on direct imageries in H-alpha, blue and red; the detailed shape of the nebular structure of WRA 751 is unresolved. From the comparitive study, we conclude that WRA 751 has properties which fit well the LBV properties at minimum-brightness phase, and possesses circumstellar material with similar observational properties as those of the known LBVs AG Car and HR Car. C1 CHINA CTR ADV SCI & TECHNOL, WORLD LAB, BEIJING 100080, PEOPLES R CHINA. NASA, GODDARD SPACE FLIGHT CTR, IUE OBSERV, ASTRON PROGRAMS, GREENBELT, MD 20771 USA. CHINESE ACAD SCI, BEIJING ASTRON OBSERV, BEIJING, PEOPLES R CHINA. RP DEWINTER, D (reprint author), UNIV AMSTERDAM, ASTRON INST ANTON PANNEKOEK, KRUISLAAN 403, 1098 SJ AMSTERDAM, NETHERLANDS. NR 27 TC 14 Z9 14 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 APR PY 1992 VL 257 IS 2 BP 632 EP 640 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HQ506 UT WOS:A1992HQ50600034 ER PT J AU FISCHER, ML ALSOP, DC CHENG, ES CLAPP, AC COTTINGHAM, DA GUNDERSEN, JO KOCH, TC KREYSA, E MEINHOLD, PR LANGE, AE LUBIN, PM RICHARDS, PL SMOOT, GF AF FISCHER, ML ALSOP, DC CHENG, ES CLAPP, AC COTTINGHAM, DA GUNDERSEN, JO KOCH, TC KREYSA, E MEINHOLD, PR LANGE, AE LUBIN, PM RICHARDS, PL SMOOT, GF TI A BOLOMETRIC MILLIMETER-WAVE SYSTEM FOR OBSERVATIONS OF ANISOTROPY IN THE COSMIC MICROWAVE BACKGROUND-RADIATION ON MEDIUM ANGULAR SCALES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; INSTRUMENTATION PHOTOMETERS ID FILTERS; HORN AB We report the performance of a bolometric system designed to measure the anisotropy of the cosmic microwave background (CMB) radiation on angular scales from 0-degrees-3 to 3-degrees. The system represents a collaborative effort combining a low-background 1 m diameter balloon-borne telescope with new multimode feed optics, a beam modulation mechanism with high stability, and a four-channel bolometric receiver with passbands centered near frequencies of 3 (90), 6 (180), 9 (270), and 12 (360) cm-1 (GHz). The telescope has been flown three times with the bolometric receiver and has demonstrated detector noise limited performance capable of reaching sensitivity levels of DELTA-T/T(CMB) almost-equal-to 10(-5) with detectors operated at T = 0.3 K. C1 UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. MAX PLANCK INST RADIOASTRON,W-5300 BONN,GERMANY. RP FISCHER, ML (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Alsop, David/J-5764-2013 OI Alsop, David/0000-0002-8206-1995 NR 31 TC 38 Z9 38 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 APR 1 PY 1992 VL 388 IS 2 BP 242 EP 252 DI 10.1086/171148 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM051 UT WOS:A1992HM05100003 ER PT J AU CAULET, A WOODGATE, BE BROWN, LW GULL, TR HINTZEN, P LOWENTHAL, JD OLIVERSEN, RJ ZIEGLER, MM AF CAULET, A WOODGATE, BE BROWN, LW GULL, TR HINTZEN, P LOWENTHAL, JD OLIVERSEN, RJ ZIEGLER, MM TI FABRY-PEROT IMAGES OF NGC 1275 AND ITS PUZZLING HIGH-VELOCITY SYSTEM SO ASTROPHYSICAL JOURNAL LA English DT Article DE COOLING FLOWS; GALAXIES INDIVIDUAL (NGC 1275); GALAXIES INTERACTIONS; GALAXIES KINEMATICS AND DYNAMICS; GALAXIES SEYFERT ID EMISSION-LINE GAS; STAR FORMATION; ACCRETION FLOW; GIANT GALAXIES; COOLING FLOWS; PERSEUS-A; NGC-1275; CLUSTERS; FILAMENTS; EXTINCTION AB We report the first images obtained with the Goddard Fabry-Perot imager, a very sensitive and tunable imaging system designed to achieve the high levels of performance required in the optical studies of faint emission-line extragalactic objects. A velocity sequence of calibrated narrow-band CCD images (FWHM approximately 7 angstrom) has been obtained to cover the 3000 km s-1 velocity space between the redshifted H-alpha-emission lines of NGC 1275 (the central dominant galaxy of the Perseus Cluster), its extended associated system of low-velocity (LV) filaments and the high-velocity (HV) system of knots, projected on the same line of sight in the sky. The lack of intermediate-velocity emission-line gas between the two systems leads to an upper limit of 1.5 x 10(-16) ergs cm-2 s-1 arcsec-2 (3-sigma) on stripped ionized gas due to dynamical interaction between NGC 1275 and its high-velocity companion galaxy. It also confirms the previous reports that the level of continuum light arising from stellar or nonstellar sources must be very low in otherwise bright, strongly concentrated emission-line knots with unresolved diameters of 425 h-1 pc. The two galaxies are well separated kinematically. We have measured the H-alpha-luminosities of the emission-line regions of the two systems and have derived star formation rates in order to investigate quantitatively the physical relation between the HV galaxy, NGC 1275, and the surrounding cooling flow filaments. We found that the 3' diameter region around NGC 1275 has a total observed H-alpha-luminosity of 5 x 10(41) h-2 ergs s-1, a factor of 2.5 lower than a currently popular value (based on 1983 data). On the other hand, our measurements of central regions match other published values. Implications of this new measurement are discussed in the context of cooling flows. Corrected for Galactic foreground absorption, the H-alpha-luminosity of NGC 1275 of L(G)(H-alpha) approximately 1.2 x 1.2 x 10(42) h-2 ergs s-1 is comparable to those of other strong cooling flows. A normal initial mass function (IMF) for star formation in NGC 1275 is consistent with published X-ray, UV, and optical data in this paper. In particular, the revised H-alpha-luminosity of a strong emission-line extranuclear region can be reconciled with the limit on its continuum UV flux at 1250 angstrom; therefore, the exclusion of stars more massive than 25 M. is no longer needed. Also, the hypothesis of a low-mass cutoff to the IMF at 2 M., which had been introduced to reconcile the star formation rate (SFR) derived from the H-alpha-luminosity with the mass deposition rate of X-ray gas (M(x)), is not needed when the revised value SFR approximately 10 h-2 M. yr-1 is compared with the similar value M(x) approximately 7.5-15 h-2 M. yr-1 within the 30" radius central region. In the HV galaxy, the H-alpha-luminosities of 13 regions have been measured in six narrow-band images, leading to a total observed luminosity L(H-alpha) = 7.2 x 10(40) h-2 ergs s-1 over a surface area of 877 arcsec2. The star formation rate SFR approximately 1 h-2 M. yr-1 corresponds to a total stellar mass of 12 x 10(6) h-2 M. if massive stars ionize the H-alpha-knots. The collision of gas clouds in a heterogeneous intracluster medium with the fast-moving HV galaxy has been modeled. Following the collision, the HV interstellar medium becomes violently perturbed, with giant expanding cavities sweeping considerable masses of gas. Star formation with a 2-4 h-2 % efficiency in the HV shocked disk supershells may occur under favorable conditions 1-8 Myr after the collision event. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. EUROPEAN SO OBSERV,SPACE TELESCOPE EUROPEAN COORDINATING FACIL,W-8046 GARCHING,GERMANY. UNIV NEVADA,LAS VEGAS,NV 89154. UNIV ARIZONA,STENARD OBSERV,TUCSON,AZ 85721. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 46 TC 40 Z9 40 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1992 VL 388 IS 2 BP 301 EP & DI 10.1086/171153 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM051 UT WOS:A1992HM05100008 ER PT J AU CARLSON, BE LACIS, AA ROSSOW, WB AF CARLSON, BE LACIS, AA ROSSOW, WB TI THE ABUNDANCE AND DISTRIBUTION OF WATER-VAPOR IN THE JOVIAN TROPOSPHERE AS INFERRED FROM VOYAGER IRIS OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE PLANETS AND SATELLITES; INDIVIDUAL (JUPITER) ID GIANT PLANETS; EQUATORIAL REGION; OPTICAL-CONSTANTS; GAS-COMPOSITION; JUPITER; ATMOSPHERE; ABSORPTION; AMMONIA; 5-MU-M; CLOUDS AB We have reanalyzed the Voyager IRIS spectra of the Jovian North Equatorial Belt (NEB) hot spots using a radiative transfer model which includes the full effects of anisotropic multiple scattering by clouds. The atmospheric model includes the three thermochemically predicted cloud layers, NH3, NH4SH, and H2O. Spectrally dependent cloud extinction is modeled using Mie theory and the refractive indices of NH3 ice, NH4SH ice, water, and H2O ice. The upper tropospheric temperature profile, gas abundances, height-dependent para-hydrogen profile, and vertical distribution of NH3 cloud opacity are retrieved from an analysis of the far-infrared (180-1200 cm-1) IRIS observations. With these properties constrained, the 5-mu-m (1800-2300 cm-1) observations are analyzed to determine the atmospheric and cloud structure of the deeper atmosphere (P > 1.5 bars). Since the NEB hot spots correspond to regions of minimum cloud opacity, these observations allow us to probe the atmosphere down to the almost-equal-to 5 bar level. The results show that the abundance of water is at least 1.5 times solar with 2 times solar (2.76 x 10(-3) mixing ratio relative to H-2) providing the best-fit to the Voyager IRIS hot spot observations. We then use IRIS observations of the Tropical and Equatorial regions to examine spatial variations in relative humidity. Our results show that regions with average 5-mu-m brightness temperatures in excess of 230 K are areas of reduced relative humidity, while colder regions are best-fit with a saturated water profile. RP CARLSON, BE (reprint author), GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. RI Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; Rossow, William/F-3138-2015 NR 51 TC 39 Z9 39 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1992 VL 388 IS 2 BP 648 EP 668 DI 10.1086/171182 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM051 UT WOS:A1992HM05100037 ER PT J AU BURNS, JO SULKANEN, ME GISLER, GR PERLEY, RA AF BURNS, JO SULKANEN, ME GISLER, GR PERLEY, RA TI WHERE HAVE ALL THE CLUSTER HALOS GONE SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, CLUSTERING; INTERGALACTIC MEDIUM; MAGNETIC FIELDS; POLARIZATION; RADIO CONTINUUM, GALAXIES; X-RAYS, GALAXIES ID DIFFUSE RADIO-EMISSION; MAGNETIC-FIELDS; GALAXY CLUSTERS; COMA CLUSTER; PERSEUS CLUSTER; COOLING FLOWS; GAS AB A new low-frequency (330 MHz) VLA image of the Perseus cluster confirms the presence of a mini-radio halo with diameter approximately 430 kpc (H0 = 75 km s-1 Mpc-1) surrounding 3C 84. A careful comparison with the Coma cluster shows that there is no evidence for a similar, very extended halo in Perseus despite the large number of cluster radio galaxies which could power such a halo. These two clusters represent two classes of radio halos which differ by the absence (Coma) or presence (Perseus) of cooling inflows. We argue that smaller halos as in Perseus result from insufficient cluster-wide magnetic fields. A simple model is presented which suggests that cooling flows can suppress the diffusion of turbulently amplified B-fields outward from the cluster core. Such a suppression leads to the development of minihalos which are confined to the cores of cooling flow clusters. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB ES65,HUNTSVILLE,AL 35812. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801. RP BURNS, JO (reprint author), NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003, USA. NR 25 TC 50 Z9 50 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 1 PY 1992 VL 388 IS 2 BP L49 EP L52 DI 10.1086/186327 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM052 UT WOS:A1992HM05200002 ER PT J AU BENNETT, CT SCHWIRZKE, M AF BENNETT, CT SCHWIRZKE, M TI ANALYSIS OF ACCIDENTS DURING INSTRUMENT APPROACHES SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article AB General aviation and air taxi approach phase accidents, which occurred during Visual and Instrument Flight Rules (VFR and IFR, respectively) over the last 25 years, were analyzed. The data suggest that there is a 204% higher risk during the approach and landing phase of VFR flights, than during similar IFR operations (14.82 vs. 7.27 accidents/100,000 approaches). Alarmingly, the night single pilot IFR (SPIFR) accident rate is almost 8 times the rate of day IFR, 35.43 vs. 4.47 accidents/100,000 approaches, and two and a half times that of day VFR approaches, 35.43 vs. 14.82 accidents/100,000 approaches. Surprisingly, the overall SPIFR accident rates are not much higher than dual-pilot IFR (DPIFR), 7.27 vs. 6.48 accidents/100,000 approaches. The generally static ratio of the statistics for SPIFR/DPIFR accident rates may be accounted for by little or no change in general aviation cockpit technology during the last 25 years, and because IFR operational flight task management training has not kept pace. RP BENNETT, CT (reprint author), NASA,AMES RES CTR,M-S 262-3,MOFFETT FIELD,CA 94035, USA. NR 11 TC 10 Z9 10 U1 1 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 APR PY 1992 VL 63 IS 4 BP 253 EP 261 PG 9 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA HL735 UT WOS:A1992HL73500002 PM 1610333 ER PT J AU SMITH, MK AF SMITH, MK TI REGIONAL DIFFERENCES IN OTOLITH MORPHOLOGY OF THE DEEP SLOPE RED SNAPPER ETELIS-CARBUNCULUS SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID FISH OTOLITHS; SHAPE-ANALYSIS; GROWTH; ULTRASTRUCTURE AB Sagittal otoliths from four populations of the Pacific deep slope red snapper Etelis carbunculus Cuvier were compared using Fourier descriptors and other shape indices, linear proportions, and dry weight. Otoliths from Hawaii, Vanuatu, Fiji and French Polynesia and a small number from the Commonwealth of the Northern Marianas Islands (NMI) were examined. Regional shape and weight characteristics were distinguishable, despite the wide range of individual variation and limited available size range from some regions. Size-specific differences in otolith shape were found for the four regions for which a sufficient sample was available. Otoliths from Hawaii, French Polynesia, and NMI showed a significant shape affinity. Otoliths from Fiji and Vanuatu were similarly shaped and were distinct from those from the other three regions. Interregional otolith shape affinities for the stocks examined parallel similarities in maximum size and growth rate from the literature, suggesting that growth rate may influence otolith shape. Observed trends in otolith weight as a function of fish length support growth-related regional differences in otolith shape. C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. NR 43 TC 55 Z9 65 U1 1 U2 7 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1992 VL 49 IS 4 BP 795 EP 804 DI 10.1139/f92-090 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA HL305 UT WOS:A1992HL30500019 ER PT J AU MAUNG, KM DEUTCHMAN, PA BUVEL, RL AF MAUNG, KM DEUTCHMAN, PA BUVEL, RL TI THEORETICAL SHELL-MODEL SIGNATURES IN HEAVY-ION, COHERENT PION-PRODUCTION SO CANADIAN JOURNAL OF PHYSICS LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; GIANT-RESONANCE FORMATION; SUBTHRESHOLD PIONS; CROSS-SECTIONS; ISOBAR; BREMSSTRAHLUNG; DISTRIBUTIONS; SCATTERING AB A comprehensive summary of a many-body, microscopic, particle-hole formalism is presented that describes coherent, subthreshold, pion production in peripheral, heavy-ion collisions. The formalism uses a new separable model transition interaction that produces DELTA-hole states in either the projectile or target nucleus. Shell-model states described by harmonic oscillator functions are used in the calculation of DELTA-formation and decay and Lorentz-contraction effects of the nucleus not at rest are included. An analytical expression to lowest multipole order for the differential cross section is examined. The sensitivity of the theoretical results to the shell-model states is determined with preliminary shape results compared with data. The effects of higher multipoles are examined with attention paid to the second-order multipole value. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV IDAHO,DEPT PHYS,MOSCOW,ID 83843. RP MAUNG, KM (reprint author), HAMPTON UNIV,DEPT PHYS,HAMPTON,VA 23668, USA. NR 45 TC 2 Z9 2 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD APR PY 1992 VL 70 IS 4 BP 202 EP 215 PG 14 WC Physics, Multidisciplinary SC Physics GA JC710 UT WOS:A1992JC71000003 ER PT J AU BRILL, RW BUSHNELL, PG JONES, DR SHIMIZU, M AF BRILL, RW BUSHNELL, PG JONES, DR SHIMIZU, M TI EFFECTS OF ACUTE TEMPERATURE-CHANGE, INVIVO AND INVITRO, ON THE ACID-BASE STATUS OF BLOOD FROM YELLOWFIN TUNA (THUNNUS-ALBACARES) SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID TROUT SALMO-GAIRDNERI; KATSUWONUS-PELAMIS BLOOD; SKIPJACK TUNA; CHANNEL CATFISH; CARBON-DIOXIDE; FISH; PH; THERMOREGULATION; EXERCISE AB In most fishes, blood acid - base regulation following a temperature change involves active adjustments of gill ion-exchange rates which take hours or days to complete. Previous studies have shown that isolated blood from skipjack tuna, Katsuwonus pelamis, and albacore, Thunnus alalunga, had rates of pH change with temperature (in the open system) equivalent to those necessary to retain net protein charge in vivo (almost-equal-to -0.016-DELTA-pH . degrees-C-1). It was postulated that this is due to protons leaving the hemoglobin combining with plasma bicarbonate (HCO3-), which is removed as gaseous CO2, and that this ability evolved so that tunas need not adjust gill ion-exchange rates to regulate blood pH appropriately following ambient temperature changes. We reexamined this phenomenon using blood and separated plasma from yellowfin tuna, Thunnus albacares. Unlike previous studies, our CO2 levels (0.5 and 1.5 % CO2) span those seen in yellowfin tuna arterial and venous blood. Various bicarbonate concentrations ([HCO3-]) were obtained by collecting blood from fully rested as well as vigorously exercised fish. We use our in vitro data to calculate basic physiochemical parameters for yellowfin tuna blood: nonbicarbonate buffering (beta), the apparent first dissociation constant of carbonic acid (pK(app)), and CO2 Solubility (alpha-CO2). We also determined the effects of acute temperature change on arterial pH, [HCO3-], and partial pressures of O2 and CO2 in vivo. The pH shift of yellowfin tuna blood subjected to a closed-system temperature change did not differ from previous studies of other teleosts (almost-equal-to -0.016-DELTA-pH . degrees-C-1). The pH shift in blood subjected to open-system temperature change was Pco2 dependent and lower than that in skipjack tuna or albacore blood in vitro, but identical with that seen in yellowfin tuna blood in vivo. However, pH adjustments in vivo were caused by changes in both [HCO3-] and Pco2. The exact mechanisms responsible for these changes remain to be elucidated. C1 UNIV BRITISH COLUMBIA,DEPT ZOOL,VANCOUVER V6T 2A9,BC,CANADA. UNIV CALIF IRVINE,DEPT ECOL & EVOLUT BIOL,IRVINE,CA 92717. RP BRILL, RW (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 43 TC 7 Z9 7 U1 2 U2 6 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD APR PY 1992 VL 70 IS 4 BP 654 EP 662 DI 10.1139/z92-098 PG 9 WC Zoology SC Zoology GA JB043 UT WOS:A1992JB04300004 ER PT J AU ALTMAN, J CHAN, J GRYMES, RA BAUER, EA AF ALTMAN, J CHAN, J GRYMES, RA BAUER, EA TI SUPPRESSION OF COLLAGENASE-I EXPRESSION IN PROGERIOD FIBROBLASTS BY HYDROCORTISONE SO CLINICAL RESEARCH LA English DT Meeting Abstract C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DERMATOL,STANFORD,CA 94305. NASA,AMES RES CTR,DEPT LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SLACK INC PI THOROFARE PA 6900 GROVE RD, THOROFARE, NJ 08086 USA SN 0009-9279 J9 CLIN RES JI Clin. Res. PD APR PY 1992 VL 40 IS 2 BP A488 EP A488 PG 1 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA HN741 UT WOS:A1992HN74102016 ER PT J AU KORENFELD, CD GRYMES, RA HOEFFLER, WK BAUER, EA AF KORENFELD, CD GRYMES, RA HOEFFLER, WK BAUER, EA TI THE WERNER SYNDROME COLLAGENASE PROMOTER CONTAINS A NORMAL AP-1 SITE SO CLINICAL RESEARCH LA English DT Meeting Abstract C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DERMATOL,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SLACK INC PI THOROFARE PA 6900 GROVE RD, THOROFARE, NJ 08086 USA SN 0009-9279 J9 CLIN RES JI Clin. Res. PD APR PY 1992 VL 40 IS 2 BP A189 EP A189 PG 1 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA HN741 UT WOS:A1992HN74100309 ER PT J AU KROGH, FT AF KROGH, FT TI NOTES ON A VERY FAST SUBSTRING SEARCH ALGORITHM SO COMMUNICATIONS OF THE ACM LA English DT Letter RP KROGH, FT (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 SN 0001-0782 J9 COMMUN ACM JI Commun. ACM PD APR PY 1992 VL 35 IS 4 BP 132 EP 132 PG 1 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA HK941 UT WOS:A1992HK94100018 ER PT J AU ROWE, GT PHOEL, WC AF ROWE, GT PHOEL, WC TI NUTRIENT REGENERATION AND OXYGEN-DEMAND IN BERING SEA CONTINENTAL-SHELF SEDIMENTS SO CONTINENTAL SHELF RESEARCH LA English DT Article ID MIDDLE ATLANTIC BIGHT; MARINE-SEDIMENTS; ORGANIC-MATTER; PHYTOPLANKTON GROWTH; CHUKCHI SEAS; AMINO-ACIDS; CARBON; COASTAL; NITROGEN; CONSUMPTION AB Measurements of seabed oxygen demand and nutrient regeneration were made on continental shelf sediments in the southeast Bering Sea from 1 to 15 June 1981. The mean seabed oxygen demand was relatively modest (267-mu-M O2 m-2 h-1), equivalent to a utilization of 60 mg organic carbon m-2 day-1. The seasonal build up of ammonium over the mid-shelf domain was generated at least in part by the bottom biota, as previously suggested (WHITLEDGE et al., 1986, Continental Shelf Research, 5, 109-132), but on the outer shelf nitrate replaced ammonium as the dominant inorganic nitrogen compound that was regenerated from the sediments. Comparison of oxygen consumption with the organic matter in sedimenting particulate matter (sampled with sediment traps) could imply that benthic processes were not accounting for the fate of considerable quantities of organic matter. Benthic oxygen demand rates, however, probably lag behind the input of the spring bloom to the bottom, thus extending the remineralization process out over time. Consumption by small microheterotrophs in the water column was also a likely sink, although shelf export and advective transport north were possible as well. Estimated nitrification rates in surface sediments could account for only a small fraction of the abrupt increase in nitrate observed in the water column over the shelf just prior to the spring bloom. C1 NOAA,NATL MARINE FISHERIES SERV,SANDY HOOK LAB,HIGHLANDS,NJ 07732. RP ROWE, GT (reprint author), TEXAS A&M UNIV SYST,COLLEGE STN,TX 77843, USA. NR 47 TC 20 Z9 21 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD APR PY 1992 VL 12 IS 4 BP 439 EP 449 DI 10.1016/0278-4343(92)90085-X PG 11 WC Oceanography SC Oceanography GA HM301 UT WOS:A1992HM30100001 ER PT J AU SELBY, GV LIN, JC HOWARD, FG AF SELBY, GV LIN, JC HOWARD, FG TI CONTROL OF LOW-SPEED TURBULENT SEPARATED FLOW USING JET VORTEX GENERATORS SO EXPERIMENTS IN FLUIDS LA English DT Article AB A parametric study has been performed with jet vortex generators to determine their effectiveness in controlling flow separation associated with low-speed turbulent flow over a two-dimensional rearward-facing ramp. Results indicate that flow-separation control can be accomplished, with the level of control achieved being a function of jet speed, jet orientation (with respect to the free-stream direction), and jet location (distance from the separation region in the free-stream direction). Compared to slot blowing, jet vortex generators can provide an equivalent level of flow control over a larger spanwise region (for constant jet flow area and speed). C1 NASA,LANGLEY RES CTR,EXPTL FLOW PHYS BRANCH,HAMPTON,VA 23665. RP SELBY, GV (reprint author), OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23529, USA. NR 13 TC 45 Z9 50 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD APR PY 1992 VL 12 IS 6 BP 394 EP 400 PG 7 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA HP845 UT WOS:A1992HP84500006 ER PT J AU SOMERTON, DA KOBAYASHI, DR AF SOMERTON, DA KOBAYASHI, DR TI INVERSE METHOD FOR MORTALITY AND GROWTH ESTIMATION - A NEW METHOD FOR LARVAL FISHES SO FISHERY BULLETIN LA English DT Article ID EARLY LIFE-HISTORY; NORTHERN ANCHOVY; ENGRAULIS-MORDAX; AGE; GULF; INCREMENTS; SURVIVAL; MEXICO; RATES; SIZE AB The inverse method for mortality and growth estimation (IMMAGE) is a new approach to obtain unbiased estimates of mortality and growth parameters for larval fishes from length-frequency data biased by the size selectivity of plankton nets. The performance of IMMAGE is compared with methods which attempt to eliminate selection bias from sampled length-frequencies. Using Monte Carlo simulations, IMMAGE estimates growth and mortality parameters that are more accurate and precise than those produced by other methods. C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. RP SOMERTON, DA (reprint author), NOAA,NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,SEATTLE,WA 98115, USA. NR 25 TC 7 Z9 7 U1 1 U2 3 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 APR PY 1992 VL 90 IS 2 BP 368 EP 375 PG 8 WC Fisheries SC Fisheries GA JF227 UT WOS:A1992JF22700010 ER PT J AU BRAKENRIDGE, GR HAGEDORN, J AF BRAKENRIDGE, GR HAGEDORN, J TI FLOODPLAIN EVOLUTION - INTRODUCTION SO GEOMORPHOLOGY LA English DT Editorial Material RP BRAKENRIDGE, GR (reprint author), NASA HEADQUARTERS,DIV EARTH SCI & APPLICAT,CODE SEP,WASHINGTON,DC 20546, 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 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD APR PY 1992 VL 4 IS 6 BP R3 EP R3 PG 1 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA HU895 UT WOS:A1992HU89500001 ER PT J AU GROSS, RS AF GROSS, RS TI CORRESPONDENCE BETWEEN THEORY AND OBSERVATIONS OF POLAR MOTION SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE EARTH ROTATION; LENGTH-OF-DAY; POLAR MOTION; WOBBLE ID PARAMETERS; NUTATION; EARTH AB The Earth's orientation in space changes in response to the action of a variety of torques, generated both externally and internally. External torques arising from the gravitational forces of the Sun and Moon act upon the Earth, causing it to undergo periodic motions known as the lunisolar precession and nutations. Internal dynamical processes that change the deformable Earth's inertia tensor, or that generate relative angular momentum, also cause the Earth's orientation in space to change, the resulting motions being known as wobble (or polar motion) and changes to the length-of-day. Historically, it was thought that observations determined the location of the rotation pole within some rotating reference frame fixed to the solid Earth, and theoretical expressions for the nutations and wobble were developed and given in terms of the Earth's rotation axis. However, it has been (relatively recently) argued that observatories, being located on the surface of the Earth, are more nearly moving with the Earth's surface, and hence observations more nearly reflect the motion of the Earth's figure axis, rather than its rotation or angular momentum axes. This argument was accepted by the International Astronomical Union, and the current 1980 Theory of Nutation refers to an axis, the celestial ephemeris pole, that is more closely associated with the Earth's figure axis than it is with the Earth's rotation axis. Polar motion values, as reported by modern Earth rotation services, give the location of the celestial ephemeris pole within some rotating, body-fixed reference frame. The celestial ephemeris pole does not correspond to either the Earth's instantaneous figure axis, its instantaneous rotation axis, or its instantaneous angular momentum axis, but rather corresponds to an axis that exhibits no nearly diurnal motions in either the terrestrial, body-fixed reference frame or the celestial, space-fixed frame. The focus of this paper is not on the nutational motions of the Earth generated by external torques, but rather on the wobble. The goal of this paper is to write in terms of reported values the standard theoretical equation describing the Earth's wobble, namely, the linearized conservation of angular momentum equation known as the Liouville equation. In terms of the location m(t) = m1(t) + im2(t) of the rotation pole, the Liouville equation is usually written as [GRAPHICS] where the complex-valued chi-functions are functions of perturbations to the Earth's inertia tensor and relative angular momentum. In order to rewrite this equation in terms of the location p(t) = p1(t) + ip2(t) of the reported pole, a relation between the locations of the rotation pole and the celestial ephemeris pole must be obtained. This is accomplished in the time domain by considering the properties of the time-dependent transformation matrix that relates components of a position vector in the rotating, body-fixed frame to its components in the celestial, space-fixed frame, the resulting relation being [GRAPHICS] Using this expression relating the location of the rotation pole to that of the celestial ephemeris pole, the linearized conservation of angular momentum equation becomes [GRAPHICS] Thus, there is no chi-term in the Liouville equation describing long-period polar motions when it is written in terms of reported valves. RP GROSS, RS (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 30 TC 76 Z9 77 U1 1 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD APR PY 1992 VL 109 IS 1 BP 162 EP 170 DI 10.1111/j.1365-246X.1992.tb00086.x PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HK680 UT WOS:A1992HK68000012 ER PT J AU DISANTI, MA MUMMA, MJ LACY, JH PARMAR, P AF DISANTI, MA MUMMA, MJ LACY, JH PARMAR, P TI A POSSIBLE DETECTION OF INFRARED-EMISSION FROM CARBON-MONOXIDE IN COMET AUSTIN (1989C1) SO ICARUS LA English DT Article ID HALLEY; ABUNDANCE; P/HALLEY; CO C1 UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. RP DISANTI, MA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,PLANETARY SYST BRANCH,GREENBELT,MD 20771, USA. RI mumma, michael/I-2764-2013 NR 32 TC 11 Z9 11 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 1992 VL 96 IS 2 BP 151 EP 160 DI 10.1016/0019-1035(92)90068-I PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HU441 UT WOS:A1992HU44100001 ER PT J AU PIRRAGLIA, JA AF PIRRAGLIA, JA TI INSTABILITY OF THE ZONAL JETS AND LONGITUDINAL THERMAL WAVES IN A JOVIAN ATMOSPHERE SO ICARUS LA English DT Article ID JUPITER RP PIRRAGLIA, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771, USA. NR 7 TC 2 Z9 2 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 APR PY 1992 VL 96 IS 2 BP 161 EP 168 DI 10.1016/0019-1035(92)90069-J PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HU441 UT WOS:A1992HU44100002 ER PT J AU ZISK, SH MOUGINISMARK, PJ GOLDSPIEL, JM SLADE, MA JURGENS, RF AF ZISK, SH MOUGINISMARK, PJ GOLDSPIEL, JM SLADE, MA JURGENS, RF TI VALLEY SYSTEMS ON TYRRHENA-PATERA, MARS - EARTH-BASED RADAR MEASUREMENTS OF SLOPES SO ICARUS LA English DT Article ID EVOLUTION; VOLCANO; ORIGIN C1 CORNELL UNIV,CTR RADIOPHYS & SPACE RES,ITHACA,NY 14853. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP ZISK, SH (reprint author), UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,DEPT GEOL & GEOPHYS,HONOLULU,HI 96822, USA. NR 22 TC 5 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD APR PY 1992 VL 96 IS 2 BP 226 EP 233 DI 10.1016/0019-1035(92)90077-K PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HU441 UT WOS:A1992HU44100010 ER PT J AU WILLIAMS, JG AF WILLIAMS, JG TI ASTEROID FAMILIES - AN INITIAL SEARCH SO ICARUS LA English DT Article ID APOLLO-AMOR OBJECTS; MINOR PLANETS; SECULAR RESONANCE; ORIGIN; DISTRIBUTIONS; METEORITES; SYSTEM; BELT RP WILLIAMS, JG (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 81 TC 47 Z9 47 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 APR PY 1992 VL 96 IS 2 BP 251 EP 280 DI 10.1016/0019-1035(92)90079-M PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HU441 UT WOS:A1992HU44100012 ER PT J AU DALL, J JORGENSEN, JH CHRISTENSEN, EL MADSEN, SN AF DALL, J JORGENSEN, JH CHRISTENSEN, EL MADSEN, SN TI REAL-TIME PROCESSOR FOR THE DANISH AIRBORNE SAR SO IEE PROCEEDINGS-F RADAR AND SIGNAL PROCESSING LA English DT Article DE SYNTHETIC APERTURE RADAR; REMOTE SENSING; DSP AB The design of the Danish high resolution SAR was started in 1986, and the initial test flights took place in November and December 1989. An airborne real-time processor is currently under development, and a first reduced version is expected to be operational in mid-1992. The real-time processor is primarily intended to assist the operator in using the SAR system, but since the processor has been designed to produce high quality imagery, it is expected to render offline processing superfluous in many cases. The range-Doppler algorithm is adopted and supplemented with an extensive motion compensation taking into account the special conditions associated with real time strip mapping of large scenes. From an architectural point of view the processor is a pipeline of approximately 20 elements interconnected by a dedicated data path and a control bus. Only three different types of elements are involved: a programmable signal processing element, a multipurpose memory element and a multipurpose interface element. Two commercially available control boards and a display system support the pipeline. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP DALL, J (reprint author), TECH UNIV DENMARK,INST ELECTROMAGNET,BLDG 348,DK-2800 LYNGBY,DENMARK. NR 7 TC 15 Z9 17 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0956-375X J9 IEE PROC-F PD APR PY 1992 VL 139 IS 2 BP 115 EP 121 PG 7 WC Telecommunications SC Telecommunications GA HP556 UT WOS:A1992HP55600003 ER PT J AU RODRIGUEZ, E MARTIN, JM AF RODRIGUEZ, E MARTIN, JM TI THEORY AND DESIGN OF INTERFEROMETRIC SYNTHETIC APERTURE RADARS SO IEE PROCEEDINGS-F RADAR AND SIGNAL PROCESSING LA English DT Article DE SYNTHETIC APERTURE RADAR; INTERFEROMETRY; GLOBAL TOPOGRAPHY AB Interferometric synthetic aperture radar (InSAR) is a method which may provide a means of estimating global topography with high spatial resolution and height accuracy. The paper presents a derivation of the signal statistics, an optimal estimator of the interferometric phase, and the expressions necessary to calculate the height-error budget. These expressions are used to derive methods of optimising the InSAR-system parameters, and are then used in a specific design example for a system to perform high-resolution global topographic mapping with a one-year mission lifetime, subject to current technological constraints. Finally, a Monte Carlo simulation of this InSAR system is performed to evaluate its performance for realistic topography. The results indicate that this system has the potential to satisfy the stringent accuracy and resolution requirements for geophysical use of global topographic data. RP RODRIGUEZ, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 323 Z9 371 U1 3 U2 27 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0956-375X J9 IEE PROC-F PD APR PY 1992 VL 139 IS 2 BP 147 EP 159 PG 13 WC Telecommunications SC Telecommunications GA HP556 UT WOS:A1992HP55600006 ER PT J AU HEMMATI, H LESH, JR AF HEMMATI, H LESH, JR TI HIGH REPETITION-RATE Q-SWITCHED AND INTRACAVITY DOUBLED DIODE-PUMPED ND-YAG LASER SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB A Nd:YAG laser was end pumped with 2.2 W of continuous-wave (CW) diode laser output. Efficient operation of the laser at high repetition rates was emphasized. This laser provides 890 mW of TEM00 CW output at 1064 nm, and 340 mW of 532 nm average power at a Q-switched repetition rate of 25 kHz. Experimental data are compared with analysis. RP HEMMATI, H (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 17 TC 7 Z9 8 U1 1 U2 4 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 APR PY 1992 VL 28 IS 4 BP 1018 EP 1020 DI 10.1109/3.135221 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA HP653 UT WOS:A1992HP65300033 ER PT J AU MCGUCKIN, BT MENZIES, RT AF MCGUCKIN, BT MENZIES, RT TI EFFICIENT CW DIODE-PUMPED TM, HO-YLF LASER WITH TUNABILITY NEAR 2.067 MU-M SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB A conversion efficiency of 42% and slope efficiency of approximately 60% relative to absorbed pump power are reported from a continuous wave diode-pumped Tm, Ho:YLF laser at 2-mu-m with output power of 84 mW at sub-ambient temperatures. The emission spectrum is etalon tunable over a range of 16 cm-1 centered on 2.067-mu-m with fine tuning capability of the transition frequency with crystal temperature at a measured rate of approximately -0.03 cm-1. K-1. The effective emission cross section is measured to be 5 x 10(-21) cm2. These and other aspects of the laser performance are discussed in the context of calculated atmospheric absorption characteristics in this spectral region and potential use in remote sensing applications. RP MCGUCKIN, BT (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 16 TC 36 Z9 39 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1992 VL 28 IS 4 BP 1025 EP 1028 DI 10.1109/3.135223 PG 4 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA HP653 UT WOS:A1992HP65300035 ER PT J AU HEMMATI, H AF HEMMATI, H TI DIODE-PUMPED SELF-FREQUENCY-DOUBLED NEODYMIUM YTTRIUM ALUMINUM BORATE (NYAB) LASER SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB Over 50 mW of the fundamental-mode 531 nm laser output was obtained with approximately 4% optical to optical conversion efficiency from a self frequency-doubling NYAB crystal when pumped with two 1 W diode lasers. The prospect of higher conversion efficiency is also discussed. RP HEMMATI, H (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 13 TC 65 Z9 67 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD APR PY 1992 VL 28 IS 4 BP 1169 EP 1171 DI 10.1109/3.135243 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA HP653 UT WOS:A1992HP65300055 ER PT J AU GALINDOISRAEL, V VERUTTIPONG, W NORROD, RD IMBRIALE, WA AF GALINDOISRAEL, V VERUTTIPONG, W NORROD, RD IMBRIALE, WA TI SCANNING PROPERTIES OF LARGE DUAL-SHAPED OFFSET AND SYMMETRICAL REFLECTOR ANTENNAS SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article AB Several characteristics of dual offset (DOSR) and symmetric shaped reflectors are examined herein. While shaped reflectors have the potential advantage of superior gain relative to conic section reflectors (Cassegrain and Gregorian), this advantage is obtained only at the cost of substantially reduced beam scanning capability. The added cost of manufacturing a shaped reflector antenna, particularly a doubly curved surface for the DOSR, can be somewhat ameliorated if adjustable panels, which may be necessary for correction of gravity and wind distortions, are also used for improving gain by shaping. This aspect of DOSR is examined herein. The scanning properties of shaped reflectors, both offset and circularly symmetric, are examined and compared to conic section scanning characteristics. Scanning of the pencil beam is obtained herein by lateral and axial translation of a single point source feed. The feed is kept pointed toward the center of the subreflector. The effects of power spillover and aperture phase error as a function beam scanning is examined for several different types of large reflector designs including DOSR, circularly symmetric large f/D and smaller f/D dual reflector antenna systems. It is graphically illustrated that the Abbe-sine condition for improved scanning of an optical system cannot, inherently, be satisfied in a dual-shaped reflector system that is shaped for high gain and low feed spillover. The gain loss, with scanning, of a high gain shaped reflector pair is demonstrated to be due to both aperture phase error loss and power spillover loss. Cassegrain and Gregorian reflector pairs, on the other hand, are scan limited primarily by aperture phase error-the maximum scan limit in beamwidths increasing with frequency. C1 NATL RADIO ASTRON OBSERV,GREEN BANK,WV 24944. RP GALINDOISRAEL, V (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 7 TC 8 Z9 8 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 APR PY 1992 VL 40 IS 4 BP 422 EP 432 DI 10.1109/8.138844 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HW461 UT WOS:A1992HW46100009 ER PT J AU KLUTE, GK TASCH, U GESELOWITZ, DB AF KLUTE, GK TASCH, U GESELOWITZ, DB TI AN OPTIMAL CONTROLLER FOR AN ELECTRIC VENTRICULAR-ASSIST DEVICE - THEORY, IMPLEMENTATION, AND TESTING SO IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING LA English DT Article AB This paper addresses the development and testing of an optimal position feedback controller for the Penn State electric ventricular-assist device (EVAD). The control law is designed to minimize the expected value of the EVAD's power consumption for a targeted patient population. The closed-loop control law is implemented on an Intel 8096 microprocessor and in vitro test runs show that this controller improves the EVAD's efficiency by 15-21%, when compared with the performance of the currently used feedforward control scheme. C1 PENN STATE UNIV,BIOENGN PROGRAM,UNIVERSITY PK,PA 16802. UNIV MARYLAND,DEPT MECH ENGN,CATONSVILLE,MD 21228. RP KLUTE, GK (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,ANTHROPOMENTRY & BIOMECH LAB,HOUSTON,TX 77058, USA. FU NHLBI NIH HHS [HL20356, HL13426] NR 10 TC 11 Z9 11 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 0018-9294 J9 IEEE T BIO-MED ENG JI IEEE Trans. Biomed. Eng. PD APR PY 1992 VL 39 IS 4 BP 394 EP 403 DI 10.1109/10.126612 PG 10 WC Engineering, Biomedical SC Engineering GA HK995 UT WOS:A1992HK99500009 PM 1592405 ER PT J AU KIM, WS HANNAFORD, B BEJCZY, AK AF KIM, WS HANNAFORD, B BEJCZY, AK TI FORCE-REFLECTION AND SHARED COMPLIANT CONTROL IN OPERATING TELEMANIPULATORS WITH TIME-DELAY SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article AB Shared compliant control has been incorporated into an advanced six-degree-of-freedom (6-DOF) force-reflecting telemanipulation system. With this system we have investigated the effect of time delay on human telemanipulation task performance. Time delays of between 2 and 4096 ms were introduced between master and slave arms, and high-precision peg-in-hole tasks were performed by six test operators with two modes of control: kinesthetic force feedback (KFF), and shared compliant control (SCC). Task performance was quantified in terms of the completion time (CT) and the sum of square forces (SOSF). In KFF, the operator feels forces and torques proportional to those sensed by the telerobot through the force-reflecting hand controller. Due to the instability problem, force reflection cannot be used at time delays above 0.5 to 1 s. By contrast, the force feedback loop in SCC resides entirely in the robot side, and the communication delay does not cause any stability problem. SCC enables the operator to control the telemanipulator having a compliant hand, which softens contact forces between the robot hand and objects. The experimental results demonstrate the superiority of SCC over KFF for time-delayed telemanipulation. SCC has significantly lower rates of increase than KFF in both CT and SOSF with time delay. Only SCC enabled task performance at delays above 1 s, indicating that SCC is a promising and essential scheme for time-delayed telemanipulation. Constant force maintenance tasks were also performed to investigate the effect of time delay on the stability of force reflection. SCC also has beneficial effects on telemanipulation without time delay. C1 UNIV WASHINGTON,DEPT ELECT ENGN,SEATTLE,WA 98195. RP KIM, WS (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 26 TC 160 Z9 164 U1 2 U2 16 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 APR PY 1992 VL 8 IS 2 BP 176 EP 185 DI 10.1109/70.134272 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA HQ607 UT WOS:A1992HQ60700003 ER PT J AU GENNERY, DB AF GENNERY, DB TI VISUAL TRACKING OF KNOWN 3-DIMENSIONAL OBJECTS SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article ID MOTION; IMAGES; SYSTEM AB A method is described of visually tracking a known three-dimensional object as it moves with six degrees of freedom. The method uses the predicted position of known features on the object to find the features in images from one or more cameras, measures the position of the features in the images, and uses these measurements to update the estimates of position, orientation, linear velocity, and angular velocity of the object model. The features usually used are brightness edges that correspond to markings or the edges of solid objects, although point features can be used. The solution for object position and orientation is a weighted least-squares adjustment that includes filtering over time, which reduces the effects of errors, allows extrapolation over times of missing data, and allows the use of stereo information from multiple-camera images that are not coincident in time. The filtering action is derived so as to be optimum if the acceleration is random. (Alternatively, random torque can be assumed for rotation.) The filter is equivalent to a Kalman filter, but for efficiency it is formulated differently in order to take advantage of the dimensionality of the observations and the state vector which occur in this problem. The method can track accurately with arbitrarily large angular velocities, as long as the angular acceleration (or torque) is small. Results are presented showing the successful tracking of partially obscured objects with clutter. C1 JET PROP LAB,PASADENA,CA 91109. NR 30 TC 120 Z9 120 U1 0 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0920-5691 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD APR PY 1992 VL 7 IS 3 BP 243 EP 270 DI 10.1007/BF00126395 PG 28 WC Computer Science, Artificial Intelligence SC Computer Science GA HX401 UT WOS:A1992HX40100004 ER PT J AU NEAT, GW KAUFMAN, H STEINVORTH, R AF NEAT, GW KAUFMAN, H STEINVORTH, R TI COMPARISON AND EXTENSION OF A DIRECT MODEL-REFERENCE ADAPTIVE-CONTROL PROCEDURE SO INTERNATIONAL JOURNAL OF CONTROL LA English DT Article AB This paper analyses and extends an easily implemented direct model reference adaptive control procedure. The paper focuses on the major limitation of this control approach which is the satisfaction of a stringent strictly positive real sufficiency condition in order to guarantee asymptotic tracking. Attempts, to date, to address this problem have been unable to relax simultaneously the stringent condition and maintain asymptotic tracking capabilities. This paper presents three different modifications to existing versions of this algorithm which substantially relax the stringent sufficiency condition while providing asymptotic tracking. These three modifications achieve this goal by imposing slight adjustments to existing sufficiency conditions. A simulation example demonstrates that the modifications eliminate the steady state error inherent in the existing methods. C1 RENSSELAER POLYTECH INST,DEPT ELECT COMP & SYST ENGN,TROY,NY 12180. RP NEAT, GW (reprint author), CALTECH,JET PROP LAB,SYST DESIGN & INTEGRAT GRP,PASADENA,CA 91109, USA. NR 15 TC 6 Z9 6 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0020-7179 J9 INT J CONTROL JI Int. J. Control PD APR PY 1992 VL 55 IS 4 BP 945 EP 967 DI 10.1080/00207179208934266 PG 23 WC Automation & Control Systems SC Automation & Control Systems GA HL674 UT WOS:A1992HL67400006 ER PT J AU SULLIVAN, RM SALAMON, NJ AF SULLIVAN, RM SALAMON, NJ TI A FINITE-ELEMENT METHOD FOR THE THERMOCHEMICAL DECOMPOSITION OF POLYMERIC MATERIALS .1. THEORY SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article ID MATHEMATICAL-MODEL; WOOD PYROLYSIS AB The governing differential equations are developed to model the thermomechanical behavior of chemically decomposing, polymeric materials. These equations account for thermal and gaseous diffusion through a poroelastic, transversely isotropic solid. The Bubnov-Galerkin finite element method is applied to the governing equations to cast the coupled set into a single matrix equation. A method for solving these equations simultaneously at each time step is discussed. C1 PENN STATE UNIV,DEPT ENGN SCI & MECH,UNIV PK,PA 16802. RP SULLIVAN, RM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ED24,HUNTSVILLE,AL 35812, USA. NR 14 TC 33 Z9 34 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD APR PY 1992 VL 30 IS 4 BP 431 EP 441 DI 10.1016/0020-7225(92)90035-F PG 11 WC Engineering, Multidisciplinary SC Engineering GA HF007 UT WOS:A1992HF00700003 ER PT J AU EVANS, DL AF EVANS, DL TI CURRENT STATUS AND FUTURE-DEVELOPMENTS IN RADAR REMOTE-SENSING SO ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL COLLOQUIUM ON PHYSICAL MEASUREMENTS AND SIGNATURES IN REMOTE SENSING CY JAN 14-18, 1991 CL COURCHEVEL, FRANCE SP INT SOC PHOTOGRAMMETRY & REMOTE SENSING, CTR NATL ETUDES SPACIALES, EUROPEAN SPACE AGCY, CNRS, INRA, INST FRANCAIS RES EXPLOITAT MER, AMER SOC PHOTOGRAMMETRY & REMOTE SENSING, ASSOC QUEBECOISE TELEDECT, CANADIAN REMOTE SENSING SOC, EUROPEAN ASSOC REMOTE SENSING ASSOC AB This paper briefly outlines some of the major initiatives and directions of remote sensing using Synthetic Aperture Radar (SAR) data alone and in conjunction with other sensors for earth science investigations. Specific emphasis is on areas key to global monitoring using SAR data from space-borne platforms: calibration, geophysical processing, and generation of digital elevation models. Calibration as used here encompasses end-to-end system characterization over the life of a sensor and characterization of data products relative to past and future sensors. Geophysical processing is defined here to include any processing which results in derived geophysical units. Acquisition of an additional data type, topography, is required to complete the three-dimensional view of surface properties and correct for distortions inherent in SAR. Methodologies must be developed in each of these critical areas before SAR data can be used routinely for process studies. Additional challenges include development of strategies to extrapolate from regional to global-scale models and development of new sensor technology. RP EVANS, DL (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-2716 J9 ISPRS J PHOTOGRAMM JI ISPRS-J. Photogramm. Remote Sens. PD APR PY 1992 VL 47 IS 2-3 BP 79 EP 99 DI 10.1016/0924-2716(92)90027-7 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA HW704 UT WOS:A1992HW70400002 ER PT J AU CHOUDHURY, BJ AF CHOUDHURY, BJ TI MULTISPECTRAL SATELLITE-OBSERVATIONS FOR ARID LAND STUDIES SO ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING LA English DT Article; Proceedings Paper CT 5TH INTERNATIONAL COLLOQUIUM ON PHYSICAL MEASUREMENTS AND SIGNATURES IN REMOTE SENSING CY JAN 14-18, 1991 CL COURCHEVEL, FRANCE SP INT SOC PHOTOGRAMMETRY & REMOTE SENSING, CTR NATL ETUDES SPACIALES, EUROPEAN SPACE AGCY, CNRS, INRA, INST FRANCAIS RES EXPLOITAT MER, AMER SOC PHOTOGRAMMETRY & REMOTE SENSING, ASSOC QUEBECOISE TELEDECT, CANADIAN REMOTE SENSING SOC, EUROPEAN ASSOC REMOTE SENSING ASSOC AB Multispectral satellite data when properly calibrated and standardized can be used synergistically for a quantitative analysis of processes and surface characteristics, and for quantifying land surface change. Relationships among multispectral satellite data (visible reflectance, surface temperature and polarization difference of microwave emission at 37 GHz frequency) have been used to develop hypotheses concerning the relative sensitivity of these data to varied land surface characteristics, which needs to be verified by field observations. Radiative transfer models have also been developed to understand these multispectral data. Interannual variations of visible reflectance and polarization difference for the period 1982-1986 over the Sahel and the Sudan zones of Africa show a lagged response with respect to the rainfall deficit during recovery from drought, which needs to be understood in terms of biophysical parameters. RP CHOUDHURY, BJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-2716 J9 ISPRS J PHOTOGRAMM JI ISPRS-J. Photogramm. Remote Sens. PD APR PY 1992 VL 47 IS 2-3 BP 101 EP 126 DI 10.1016/0924-2716(92)90028-8 PG 26 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA HW704 UT WOS:A1992HW70400003 ER PT J AU ARKING, A IZAKOVA, OM FEIGELSON, EM AF ARKING, A IZAKOVA, OM FEIGELSON, EM TI USING SATELLITE, SURFACE AND AEROLOGICAL INFORMATION FOR CALCULATION OF THERMAL-RADIATION FLUXES SO IZVESTIYA AKADEMII NAUK FIZIKA ATMOSFERY I OKEANA LA Russian DT Article AB Vertical profiles of upward, downward and effective fluxes of longwave radiation were calculated using data from meteorological stations, data from NOAA-9 satellite on cloud amount and cloud upper boundary temperature, and data from aerological sounding of the atmosphere. A comparison of the satellite and surface information is made. C1 MV LOMONOSOV STATE UNIV,MOSCOW 117234,USSR. RUSSIAN ACAD SCI,INST ATMOSPHER PHYS,MOSCOW,USSR. RP ARKING, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0002-3515 J9 IZV AN FIZ ATMOS OK+ JI Izv. Akad. Nauk. Fiz. Atmos. Okean. Biol. PD APR PY 1992 VL 28 IS 4 BP 378 EP 383 PG 6 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA JW858 UT WOS:A1992JW85800004 ER PT J AU SELKER, MD DALLAS, JL AF SELKER, MD DALLAS, JL TI MODELOCKED SELF-FREQUENCY DOUBLING NEODYMIUM DOPED FIBER LASER SO JOURNAL DE PHYSIQUE III LA English DT Note ID LINEAR EXTERNAL CAVITY; MODE-LOCKING; GLASS; GENERATION AB We have demonstrated simultaneous lasing and self-frequency doubling of a neodymium and germanium doped silica fiber laser at 1.06-mu-m. The doubling action is provided by a self-organized phase matching grating in the fiber. The laser was modelocked using a linear external cavity which produced 600 ps pulses at 1.06-mu-m. RP SELKER, MD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, PHOTON BRANCH, CODE 726, GREENBELT, MD 20771 USA. NR 17 TC 0 Z9 0 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 1155-4320 J9 J PHYS III JI J. Phys. III PD APR PY 1992 VL 2 IS 4 BP 675 EP 678 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Fluids & Plasmas SC Materials Science; Physics GA HK838 UT WOS:A1992HK83800012 ER PT J AU MINNIS, P HECK, PW YOUNG, DF FAIRALL, CW SNIDER, JB AF MINNIS, P HECK, PW YOUNG, DF FAIRALL, CW SNIDER, JB TI STRATOCUMULUS CLOUD PROPERTIES DERIVED FROM SIMULTANEOUS SATELLITE AND ISLAND-BASED INSTRUMENTATION DURING FIRE SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID LIQUID WATER; PARAMETERIZATION; VARIABILITY; RADIOMETER; PROJECT; MODEL AB Cloud parameters derived from visible and infrared window data from the Geostationary Operational Environmental Satellite (GOES) are compared to corresponding properties determined from instrumentation on San Nicolas Island off the coast of California during the First ISCCP Regional Experiment (FIRE) marine stratocumulus intensive field observations period in July 1987. Mean cloud amounts derived by applying the hybrid bispectral threshold method to the GOES data were 5% less than the island ceilometer measurements. Examination of the satellite imagery revealed that the apparent bias can be explained by the persistence of the clouds over the northwest part of the island during periods of clearing around the island. Diurnal variations in the cloud cover were very significant; minimum cloudiness occurred during the late afternoon and maximum cloudiness early in the morning. The satellite retrievals track this variation quite well. Satellite-derived mean cloud-top height is 53 m lower than that observed from the surface. Relationships were established between the satellite-derived cloud optical depth and two surface-observed quantities: cloud liquid water path and cloud thickness. Simultaneous observations of liquid water path and satellite-derived cloud optical depth were used to infer effective cloud-droplet radius, resulting in good agreement with correlative data. The diurnal variations in cloud amount are accompanied by changes in cloud thickness, cloud-top height, cloud liquid water path, and effective droplet size. These observations provide the most complete picture, to date, of the diurnal cycle of marine stratocumulus clouds, confirming previous satellite-based inferences of the diurnal behavior of marine stratocumulus at larger scales. Because of the limited area of the observations, further comparisons should be performed over other regions containing climatologically significant marine stratocumulus clouds. C1 LOCKHEED ENG & SCI CO,HAMPTON,VA. NOAA,WAVE PROPAGAT LAB,BOULDER,CO 80303. RP MINNIS, P (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,21 AMES RD,HAMPTON,VA 23665, USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 22 TC 160 Z9 167 U1 0 U2 10 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 APR PY 1992 VL 31 IS 4 BP 317 EP 339 DI 10.1175/1520-0450(1992)031<0317:SCPDFS>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HM313 UT WOS:A1992HM31300001 ER PT J AU BETTS, AK MINNIS, P RIDGWAY, W YOUNG, DF AF BETTS, AK MINNIS, P RIDGWAY, W YOUNG, DF TI INTEGRATION OF SATELLITE AND SURFACE DATA USING A RADIATIVE CONVECTIVE OCEANIC BOUNDARY-LAYER MODEL SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID MARINE STRATOCUMULUS CONVECTION; THERMODYNAMIC STRUCTURE; CUMULUS CONVECTION; INVERSION; PACIFIC; CLOUDS AB A mixing-line boundary-layer model is used to retrieve cloud-top height from satellite-derived cloud-top temperatures, using 700-hPa National Meteorological Center (NMC) analyses and the Comprehensive Ocean and Atmosphere Data Set (COADS) surface data as supporting datasets. Results are compared with the fixed-lapse-rate method of retrieving boundary-layer depth from sea surface temperatures (SST) and cloud-top temperatures. A radiative-convective equilibrium boundary-layer model is used to retrieve boundary-layer structure given SST and surface wind, satellite cloud-top temperatures and cloud fraction, and the 700-hPa NMC thermodynamic analyses. Good agreement is found between the COADS data and the model solutions for low-level temperature and moisture. This suggests that equilibrium boundary-layer models may be of use over remote oceans in the retrieval of boundary-layer structure. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665. APPL RES CORP,LANDOVER,MD. LOCKHEED ENGN & SCI CO,HAMPTON,VA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 28 TC 22 Z9 22 U1 1 U2 4 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 APR PY 1992 VL 31 IS 4 BP 340 EP 350 DI 10.1175/1520-0450(1992)031<0340:IOSASD>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HM313 UT WOS:A1992HM31300002 ER PT J AU BAUM, BA WIELICKI, BA MINNIS, P PARKER, L AF BAUM, BA WIELICKI, BA MINNIS, P PARKER, L TI CLOUD-PROPERTY RETRIEVAL USING MERGED HIRS AND AVHRR DATA SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SOLAR RADIATIVE-TRANSFER; DIURNAL VARIABILITY; REGIONAL CLOUD; CIRRUS CLOUDS; PARAMETERS; SCATTERING; SOUNDER; COVER AB A technique is developed that uses a multispectral, multiresolution (MSMR) method to improve the overall retrieval of mid- to high-level cloud properties by combining HIRS sounding channel data with higher spatial resolution AVHRR radiometric data collocated with the HIRS footprint. Cirrus cloud radiative and physical properties are determined using satellite data, surface-based measurements provided by rawinsondes and lidar, and aircraft-based lidar data collected during the First ISCCP (International Satellite Cloud Climatology Program) Regional Experiment (FIRE) in Wisconsin during the months of October and November 1986. HIRS cloud-height retrievals are compared to ground-based lidar and aircraft lidar when possible. Retrieval cloud heights are found to have close agreement with lidar for thin cloud, but are higher than lidar for optically thick cloud. The fact that the retrieved cloud height is higher than lidar for optically thick cloud is probably due to the attenuation of the lidar signal before the signal reaches through the cloud, while the satellite is viewing the cloud from above. AVHRR visible (0.63-mu-m) and infrared (11-mu-m) radiances are analyzed to determine the cloud emittances and reflectances collocated with each HIRS pixel. The bidirectional reflectances from the AVHRR visible-channel data are corrected for solar direct and diffuse surface reflection to isolate the cloud reflectance. The individual AVHRR pixel emittances are calculated using the cloud-top temperature derived from the HIRS cloud-retrieval analysis. The results of the reflectance-emittance relationships derived in this fashion are compared to theoretical scattering model results for both water-droplet spheres and randomly oriented hexagonal ice crystals. It is found that the assumption of 10-mu-m water droplets is inadequate to describe the reflectance-emittance relationship for the ice clouds seen here. Use of this assumption would lead to lower cloud heights using the ISCCP approach. The theoretical results show that use of hexagonal ice-crystal phase functions could lead to much improved results for cloud retrieval algorithms using a bispectral approach. C1 LOCKHEED ENGN & SCI CORP,HAMPTON,VA. RP BAUM, BA (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23665, USA. RI Baum, Bryan/B-7670-2011; Minnis, Patrick/G-1902-2010 OI Baum, Bryan/0000-0002-7193-2767; Minnis, Patrick/0000-0002-4733-6148 NR 33 TC 24 Z9 24 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 APR PY 1992 VL 31 IS 4 BP 351 EP 369 DI 10.1175/1520-0450(1992)031<0351:CPRUMH>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HM313 UT WOS:A1992HM31300003 ER PT J AU BRASUNAS, J LAKEW, B LEE, C AF BRASUNAS, J LAKEW, B LEE, C TI HIGH-TEMPERATURE-SUPERCONDUCTING MAGNETIC-SUSCEPTIBILITY BOLOMETER SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID THIN-FILMS; OPTICAL-RESPONSE AB We present a new type of infrared detector, the magnetic susceptibility bolometer, based on the temperature dependence of the diamagnetic screening of a high transition-temperature (T(c)) superconductor film near T(c). Results are reported for the response of a prototype model to modulated blackbody radiation. We discuss possible improvements and the potential sensitivity of an improved device. C1 STX CORP,LANHAM,MD 20706. N CAROLINA AGR & TECHNOL STATE UNIV,DEPT ELECT ENGN,GREENSBORO,NC 27411. RP BRASUNAS, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI brasunas, john/I-2798-2013 NR 11 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1992 VL 71 IS 7 BP 3639 EP 3641 DI 10.1063/1.350898 PG 3 WC Physics, Applied SC Physics GA HM704 UT WOS:A1992HM70400090 ER PT J AU HATHER, BM ADAMS, GR TESCH, PA DUDLEY, GA AF HATHER, BM ADAMS, GR TESCH, PA DUDLEY, GA TI SKELETAL-MUSCLE RESPONSES TO LOWER-LIMB SUSPENSION IN HUMANS SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE UNWEIGHTING; FIBER TYPES; MAGNETIC RESONANCE IMAGING; SKELETAL MUSCLE BIOPSY ID HINDLIMB SUSPENSION; SOLEUS MUSCLE; RAT SOLEUS; BED REST; ATROPHY AB Eight subjects participated in a 6-wk unilateral lower limb suspension (ULLS) study to determine the influence of reduced weight bearing on human skeletal muscle morphology. The right shoe was outfitted with a platform sole that prevented the left foot from bearing weight while walking with crutches, yet it allowed freedom of movement about the ankle, knee, and hip. Magnetic resonance images pre- and post-ULLS showed that thigh muscle cross-sectional area (CSA) decreased (P < 0.05) 12% in the suspended left lower limb, whereas right thigh muscle CSA did not change. Likewise, magnetic resonance images collected post-ULLS showed that muscle CSA was 14% smaller (P < 0.05) in the left than in the right leg. The decrease in muscle CSA of the thigh was due to a twofold greater response of the knee extensors (-16%, P < 0.05) than knee flexors (-7%, P < 0.05). The rectus femoris muscle of the knee extensors showed no change in CSA, whereas the three vastus muscles showed similar decreases of approximately 16% (P < 0.05). The apparent atrophy in the leg was due mainly to reductions in CSA of the soleus (-17%) and gastrocnemius muscles (-26%). Biopsies of the left vastus lateralis pre- and post-ULLS showed a 14% decrease (P < 0.05) in average fiber CSA. The decrease was evident in both type I (-12%) and II (-15%) fibers. The number of capillaries surrounding the different fiber types was unchanged after ULLS. Capillary density and the number of capillaries per unit CSA of type I and IIa fibers increased 15, 15, and 14%, respectively (P < 0.05). The reductions in muscle and fiber CSA after 6 wk of ULLS indicate that suspension is a viable method for unweighting human skeletal muscle to study atrophy. The results also indicate that the adaptive responses of human skeletal muscle to unweighting are qualitatively, but not quantitatively, similar to those of lower mammals and not necessarily dependent on fiber-type composition. C1 NASA,BIOMED OPERAT & RES OFF,MAIL CODE MD-M,KENNEDY SPACE CTR,FL 32899. BIONET CORP,BIOMED & ENVIRONM LABS,KENNEDY SPACE CTR,FL 32899. HOLMES REG MED CTR,ENVIRONM RESONANCE IMAGING,MELBOURNE,FL 32610. KAROLINSKA INST,DEPT PHYSIOL,PHYSIOL LAB,S-10401 STOCKHOLM 60,SWEDEN. NR 29 TC 137 Z9 140 U1 2 U2 5 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD APR PY 1992 VL 72 IS 4 BP 1493 EP 1498 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA HP086 UT WOS:A1992HP08600040 PM 1534323 ER PT J AU PICKERING, KE THOMPSON, AM SCALA, JR TAO, WK SIMPSON, J AF PICKERING, KE THOMPSON, AM SCALA, JR TAO, WK SIMPSON, J TI OZONE PRODUCTION POTENTIAL FOLLOWING CONVECTIVE REDISTRIBUTION OF BIOMASS BURNING EMISSIONS SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article; Proceedings Paper CT 7TH INTERNATIONAL SYMP OF THE COMMISSION FOR ATMOSPHERIC CHEMISTRY AND GLOBAL POLLUTION : THE CHEMISTRY OF THE GLOBAL ATMOSPHERE CY SEP 05-11, 1990 CL CHAMROUSSE, FRANCE SP COMMISS ATMOSPHER CHEM & GLOBAL POLLUT, CNRS, INST NATL SCI UNIV, CNRS, PROGRAMME ENVIRONM, MINIST ENVIRONM, MINIST RECH & TECHNOL, UNIV JOSEPH FOURIER, MINIST AFFAIRES ETRANGERES, NOAA, NATL SCI FDN, NASA ID TROPOSPHERIC OZONE; DRY SEASON; TRANSPORT; AMAZONIA; BRAZIL; FOREST; AIR; O3; CO AB The effects of deep convection on the potential for forming ozone ("ozone production potential") in the free troposphere have been simulated for regions where the trace gas composition is influenced by biomass burning. Cloud dynamical and photochemical simulations based on observations in 1980 and 1985 Brazilian campaigns form the basis of a sensitivity study of the ozone production potential under differing conditions. The photochemical fate of pollutants actually entrained in a cumulus event of August 1985 during NASA/GTE/ABLE 2A (Case 1) is compared to photochemical ozone production that could have occurred if the same storm had been located closer to regions of savanna burning (Case 2) and forest burning (Case 3). In each case studied, the ozone production potential is calculated for a 24-hour period following convective redistribution of ozone precursors and compared to ozone production in the absence of convection. In all cases there is considerably more ozone formed in the middle and upper troposphere when convection has redistributed NO(x), hydrocarbons and CO compared to the case of no convection. In the August 1985 ABLE 2A event, entrainment of a layer polluted with biomass burning into a convective squall line changes the free tropospheric cloud outflow column (5-13 km) ozone production potential from net destruction to net production. If it is assumed that the same cloud dynamics occur directly over regions of savanna burning, ozone production rates in the middle and upper troposphere are much greater. Diurnally averaged ozone production following convection may reach 7 ppbv/day averaged over the layer from 5-13 km - compared to typical free tropospheric concentrations of 25-30 ppbv O3 during nonpolluted conditions in ABLE 2A. Convection over a forested region where isoprene as well as hydrocarbons from combustion can be transported into the free troposphere leads to yet higher amounts of ozone production. RP PICKERING, KE (reprint author), UNIV SPACE RES ASSOC,NASA GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Pickering, Kenneth/E-6274-2012; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 29 TC 54 Z9 55 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD APR PY 1992 VL 14 IS 1-4 BP 297 EP 313 DI 10.1007/BF00115241 PG 17 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA HV102 UT WOS:A1992HV10200025 ER PT J AU MEHTA, VM AF MEHTA, VM TI MERIDIONALLY PROPAGATING INTERANNUAL-TO-INTERDECADAL VARIABILITY IN A LINEAR OCEAN ATMOSPHERE MODEL SO JOURNAL OF CLIMATE LA English DT Article ID NINO SOUTHERN OSCILLATION; SEA-SURFACE TEMPERATURE; EL-NINO; LEVEL PRESSURE; EQUATIONS; CLIMATE; PHYSICS AB Zonally symmetric sea level pressure perturbations have been observed to oscillate at 3-6 yr periods and travel from one polar region to the opposite polar region in approximately 10 years. Based on previous modeling of linear, meridional (zonally symmetric) modes of uncoupled ocean-atmosphere models, meridional modes of oscillation of a global, primitive-equation, coupled ocean-atmosphere model were analyzed to see if they contained meridionally propagating modes, especially surface pressure perturbations, with oscillation periods of years to decades. A two-layer model of the global ocean and a two-level model of the global atmosphere were formulated. The most important ocean-atmosphere interaction processes were parameterized in a manner consistent with the simplicity of the ocean-atmosphere models. Both models and parameterizations were linearized around axially symmetric basic states containing mean meridional circulations. The linearized perturbation system was formulated as an eigensystem. The operator matrix was discretized in the north-south direction with centered finite differences. Meridional modes of oscillation of the coupled ocean-atmosphere model were calculated. In the work reported here, calculations were performed at 2.5-degrees north-south resolution and for basic states based on observations (atmosphere) and simulations with a realistic model (ocean). For "realistic" parameter values and basic states, meridional modes oscillating at periods of several years to several decades are present in the coupled ocean-atmosphere model. Meridional surface pressure and zonal wind perturbations oscillating at 3-20-yr periods and traveling from the North Polar region to the South Polar region in 6 to 70 years appear as natural modes of variability of the coupled ocean-atmosphere model linearized in the presence of basic ocean-atmosphere states containing mean meridional circulations. At tropical latitudes, sea surface temperature perturbations are also associated with surface pressure perturbations. Oscillation periods, travel times, and meridional structures of surface pressure perturbations in some of the coupled ocean-atmosphere modes are comparable to the corresponding characteristics of the observed sea level pressure perturbations. Meridional modes oscillating at periods of a few weeks to a few centuries exist in the coupled ocean-atmosphere model only if the basic ocean-atmosphere states contain mean meridional circulations. Further work is in progress to study the sensitivity of the meridional coupled ocean-atmosphere modes to basic states and parameter values. RP MEHTA, VM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,UNIV SPACE RES ASSOC,CODE 913,GREENBELT,MD 20771, USA. NR 32 TC 7 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR PY 1992 VL 5 IS 4 BP 330 EP 342 DI 10.1175/1520-0442(1992)005<0330:MPITIV>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HQ341 UT WOS:A1992HQ34100004 ER PT J AU SHUEN, JS AF SHUEN, JS TI UPWIND DIFFERENCING AND LU FACTORIZATION FOR CHEMICAL NONEQUILIBRIUM NAVIER-STOKES EQUATIONS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID REAL GASES; IMPLICIT SCHEMES; EULER EQUATIONS RP SHUEN, JS (reprint author), NASA,LEWIS RES CTR,SVERDRUP TECHNOL INC,CLEVELAND,OH 44135, USA. NR 35 TC 62 Z9 68 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD APR PY 1992 VL 99 IS 2 BP 233 EP 250 DI 10.1016/0021-9991(92)90205-D PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA HN915 UT WOS:A1992HN91500007 ER PT J AU ARNOLD, WA WILCOX, WR CARLSON, F CHAIT, A REGEL, LL AF ARNOLD, WA WILCOX, WR CARLSON, F CHAIT, A REGEL, LL TI TRANSPORT MODES DURING CRYSTAL-GROWTH IN A CENTRIFUGE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL WORKSHOP ON MATERIAL PROCESSING IN HIGH GRAVITY CY MAY 20-25, 1991 CL DUBNA, USSR SP USSR ACAD SCI, USSR SPACE RES INST, USSR JOINT INT RES CTR, FRENCH MINIST RES TECHNOL, FRENCH CTR NATL RECH SCI MEUDON, USA, RES OFF, EUROPEAN MAT RES SOC ID SOLIDIFICATION; MELT AB A fully nonlinear three-dimensional numerical model for a centrifugal crystal growth experiment is presented. The model includes ampoule geometry and the experimentally obtained thermal profiles for the inner furnace steel cartridge insert. Results are presented based on both steady-state and fully transient models. The flow modes are presented resulting from Coriolis effects and from average resulting acceleration and the acceleration gradient, both acting on radial and axial thermal gradients. Thus far the model has been used to simulate growth at a particular experimental g equal to the value at which non-convective type impurity profiles were obtained. The flow modes resulting from different combinations of these forces can be of the same order of magnitude and interact with one another. The importance of the gradient acceleration is determined by the value of a new nondimensional number, called Ad. Thus, Coriolis effects and g gradients may have to be included in the model in order to obtain physically meaningful results. Implications of the resulting flow and thermal fields on the growing crystal at conditions available during centrifuge processing are also discussed. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. ACAD SCI USSR,SPACE RES INST,MOSCOW 117810,USSR. RP ARNOLD, WA (reprint author), CLARKSON UNIV,POTSDAM,NY 13699, USA. NR 9 TC 32 Z9 32 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1992 VL 119 IS 1-2 BP 24 EP 40 DI 10.1016/0022-0248(92)90201-S PG 17 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA HQ520 UT WOS:A1992HQ52000004 ER PT J AU SOKOLOWSKI, RS GLICKSMAN, ME AF SOKOLOWSKI, RS GLICKSMAN, ME TI GRAVITATIONAL INFLUENCE ON EUTECTIC SOLIDIFICATION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL WORKSHOP ON MATERIAL PROCESSING IN HIGH GRAVITY CY MAY 20-25, 1991 CL DUBNA, USSR SP USSR ACAD SCI, USSR SPACE RES INST, USSR JOINT INT RES CTR, FRENCH MINIST RES TECHNOL, FRENCH CTR NATL RECH SCI MEUDON, USA, RES OFF, EUROPEAN MAT RES SOC ID MACROSEGREGATION AB The study of gravitational effects on solidification has been encouraged in part by the opportunities to conduct research in the low "gravity" environment of a laboratory orbiting earth. On the other hand, centrifuges have been applied to solidifying alloys to elucidate the role of elevated gravity in determining phase equilibria and controlling macrosegregation. Research on eutectic alloy solidification under extremely high centrifugal fields in excess of 100,000 g has uncovered a wealth of new evidence demonstrating the significance of both free and convective flows in determining the extent of phase segregation. The importance of nucleation behavior is addressed, and a mechanism for the strong phase separation seen in alloys solidified in centrifugal fields is postulated on the basis of cloud formation models in atmospheric convection. C1 RENSSELAER POLYTECH INST,MAT RES CTR,TROY,NY 12180. RP SOKOLOWSKI, RS (reprint author), NASA,DIV MICROGRAV SCI & APPLICAT,WASHINGTON,DC 20546, USA. OI Glicksman, Martin/0000-0002-2675-2759 NR 22 TC 10 Z9 10 U1 0 U2 2 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 APR PY 1992 VL 119 IS 1-2 BP 126 EP 140 DI 10.1016/0022-0248(92)90212-2 PG 15 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA HQ520 UT WOS:A1992HQ52000015 ER PT J AU CURRERI, PA AF CURRERI, PA TI THE EFFECTIVENESS OF CORIOLIS DAMPENING OF CONVECTION DURING AIRCRAFT HIGH-G ARCS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 1ST INTERNATIONAL WORKSHOP ON MATERIAL PROCESSING IN HIGH GRAVITY CY MAY 20-25, 1991 CL DUBNA, USSR SP USSR ACAD SCI, USSR SPACE RES INST, USSR JOINT INT RES CTR, FRENCH MINIST RES TECHNOL, FRENCH CTR NATL RECH SCI MEUDON, USA, RES OFF, EUROPEAN MAT RES SOC ID GRAVITY LEVEL; DIRECTIONAL SOLIDIFICATION; ALLOYS; SUPERALLOY AB Directional solidification data for metal samples in KC-135 parabolic maneuvers are examined to determine evidence for Coriolis dampening of convection. Microstructural and materials properties data are examined for iron carbon, immiscible, and superalloy systems. By comparison of low-g data and high-g data with those of one-g control samples, it is determined that there is no evidence that Coriolis dampening of convective flow is effective during the 1.8 g KC-135 high-g maneuvers. A first approximation model for the high-g arc is proposed. The model yields a centrifugal radius of 20,480 ft and an angular speed of 0.397 RPM. Comparison to centrifugal solidification experiments (for an equal acceleration) where Coriolis melt growth stabilization is significant indicates that the KC-135 high-g arc is less effective in dampening convection by a factor of 100. This large difference in Coriolis dampening of convection might be taken advantage of for experiments where separation of centrifugal acceleration and Coriolis acceleration is desirable. RP CURRERI, PA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 18 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 1992 VL 119 IS 1-2 BP 141 EP 151 DI 10.1016/0022-0248(92)90213-3 PG 11 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA HQ520 UT WOS:A1992HQ52000016 ER PT J AU CHAMIS, CC MURTHY, PLN SINGHAL, SN LACKNEY, JJ AF CHAMIS, CC MURTHY, PLN SINGHAL, SN LACKNEY, JJ TI HITCAN FOR ACTIVELY COOLED HOT-COMPOSITE THERMOSTRUCTURAL ANALYSIS SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 36TH INTERNATIONAL GAS TURBINE AND AEROENGINE CONGRESS AND EXPOSITION CY JUN 03-06, 1991 CL ORLANDO, FL AB A computer code, HITCAN (High Temperature Composite Analyzer) has been developed to analyze/design hot metal matrix composite structures. HITCAN is a general purpose code for predicting the global structural and local stress-strain response of multilayered (arbitrarily oriented) metal matrix structures both at the constituent (fiber, matrix, and interphase) and the structure level and including the fabrication process effects. The thermomechanical properties of the constituents are considered to be nonlinearly dependent on several parameters, including temperature, stress, and stress rate. The computational procedure employs an incremental iterative nonlinear approach utilizing a multifactor-interaction material behavior model, i.e., the material properties are expressed in terms of a product of several factors that affect the properties. HITCAN structural analysis capabilities (static, load stepping-a multistep static analysis with material properties updated at each step, modal, and buckling) for cooled hot structures are demonstrated through a specific example problem. C1 SVERDRUP TECHNOL INC,CLEVELAND,OH 44142. RP CHAMIS, CC (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 4 TC 0 Z9 0 U1 0 U2 1 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 APR PY 1992 VL 114 IS 2 BP 315 EP 320 DI 10.1115/1.2906589 PG 6 WC Engineering, Mechanical SC Engineering GA HT254 UT WOS:A1992HT25400023 ER PT J AU KWACK, EY SHAKKOTTAI, P MASSIER, PF BACK, LH AF KWACK, EY SHAKKOTTAI, P MASSIER, PF BACK, LH TI MORPHOLOGY OF GLOBULES AND CENOSPHERES IN HEAVY FUEL-OIL BURNER EXPERIMENTS SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article ID COMBUSTION; DROPLETS; COAL AB Number 6 fuel oil was heated, sprayed, and burned in an enclosure using a small commercial oil burner. Samples of residues that emerged from the flame were collected at various locations outside the flame and observed by a scanning electron microscope. Porous cenospheres, larger globules (of size 80-mu-m to 200-mu-m) that resemble soap bubbles formed from the very viscous liquid residue, and unburned oil drops were the types of particle collected. Qualitative relationships of the morphology of these particles to the temperature history to which they were subjected were made. RP KWACK, EY (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 18 TC 3 Z9 3 U1 0 U2 1 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 APR PY 1992 VL 114 IS 2 BP 338 EP 345 DI 10.1115/1.2906594 PG 8 WC Engineering, Mechanical SC Engineering GA HT254 UT WOS:A1992HT25400028 ER PT J AU TALPALLIKAR, MV SMITH, CE LAI, MC HOLDEMAN, JD AF TALPALLIKAR, MV SMITH, CE LAI, MC HOLDEMAN, JD TI CFD ANALYSIS OF JET MIXING IN LOW NOX FLAMETUBE COMBUSTORS SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT 36TH INTERNATIONAL GAS TURBINE AND AEROENGINE CONGRESS AND EXPOSITION CY JUN 03-06, 1991 CL ORLANDO, FL AB The Rich-burn/Quick-mix/Lean-burn (RQL) combustor has been identified as a potential gas turbine combustor concept to reduce NO(x) emissions in High Speed Civil Transport (HSCT) aircraft. To demonstrate reduced NO(x) levels, cylindrical flametube versions of RQL combustors are being tested at NASA Lewis Research Center. A critical technology needed for the RQL combustor is a method of quickly mixing bypass combustion air with rich-burn gases. In this study, jet mixing in a cylindrical quick-mix section was numerically analyzed. The quick-mix configuration was five inches in diameter and employed 12 radial-inflow slots. The numerical analyses were performed with an advanced, validated 3-D Computational Fluid Dynamics (CFD) code named REFLEQS. Parametric variation of jet-to-mainstream momentum flux ratio (J) and slot aspect ratio was investigated. Both nonreacting and reacting analyses were performed. Results showed mixing and NO(x) emissions to be highly sensitive to J and slot aspect ratio. Lowest NO(x) emissions occurred when the dilution jet penetrated to approximately midradius. The viability of using 3-D CFD analyses for optimizing jet mixing was demonstrated. C1 WAYNE STATE UNIV,DETROIT,MI 48202. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP TALPALLIKAR, MV (reprint author), CFD RES CORP,HUNTSVILLE,AL 35805, USA. NR 17 TC 19 Z9 19 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 APR PY 1992 VL 114 IS 2 BP 416 EP 424 DI 10.1115/1.2906607 PG 9 WC Engineering, Mechanical SC Engineering GA HT254 UT WOS:A1992HT25400039 ER PT J AU NOOR, AK BURTON, WS AF NOOR, AK BURTON, WS TI 3-DIMENSIONAL SOLUTIONS FOR THERMAL BUCKLING OF MULTILAYERED ANISOTROPIC PLATES SO JOURNAL OF ENGINEERING MECHANICS-ASCE LA English DT Article ID SHEAR DEFORMATION; COMPOSITE PLATES AB Analytic three-dimensional elasticity solutions are presented for the thermal buckling problem of multilayered anisotropic plates. The plates are assumed to have rectangular geometry and an antisymmetric lamination with respect to the middle plane. The temperature is assumed to be independent of the surface coordinates, but it has an arbitrary symmetric variation through the thickness of the plate. No external loads are present, but the motion of the plate is partially restrained in its plane. A mixed formulation is used, with the fundamental unknowns consisting of the six stress components and the three displacement components of the plate. The prebuckling deformations are taken into account. Each of the plate variables is decomposed into symmetric and antisymmetric components in the thickness direction, and is expressed in terms of a double Fourier series in the Cartesian surface coordinates. Extensive numerical results are presented showing the effects of the prebuckling deformation on the critical temperature, as well as the effects of variation in the lamination and geometric parameters of composite plates on the importance of the transverse stress and strain components. RP NOOR, AK (reprint author), UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECH,HAMPTON,VA 23665, USA. NR 17 TC 47 Z9 48 U1 0 U2 4 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9399 J9 J ENG MECH-ASCE JI J. Eng. Mech.-ASCE PD APR PY 1992 VL 118 IS 4 BP 683 EP 701 DI 10.1061/(ASCE)0733-9399(1992)118:4(683) PG 19 WC Engineering, Mechanical SC Engineering GA HK117 UT WOS:A1992HK11700003 ER PT J AU CARTER, GA MITCHELL, RJ CHAPPELKA, AH BREWER, CH AF CARTER, GA MITCHELL, RJ CHAPPELKA, AH BREWER, CH TI RESPONSE OF LEAF SPECTRAL REFLECTANCE IN LOBLOLLY-PINE TO INCREASED ATMOSPHERIC OZONE AND PRECIPITATION ACIDITY SO JOURNAL OF EXPERIMENTAL BOTANY LA English DT Article DE PINUS-TAEDA; REFLECTANCE; OZONE; ACIDIC PRECIPITATION ID WATER-CONTENT; LEAVES; STRESS; INJURY; CONIFERS; LIGHT AB Leaf reflectance responses to increased ozone and precipitation acidity were determined at visible (400-720 nm) and infra-red (720-2500 nm) wavelengths for field-grown seedlings of loblolly pine (Pinus taeda L.). Treatments were maintained continuously from 3 April to 3 November. In a relatively ozone-sensitive variety of pine, increased ozone decreased visible and infra-red reflectance by late May. By late August, continued exposure to ozone increased visible and infra-red reflectance. As of late November, ozone at 1.7 x ambient or greater concentrations had increased visible reflectance substantially in an ozone-insensitive as well as the ozone-sensitive variety. Acidic precipitation decreased visible and infra-red reflectances in both varieties in May and decreased infra-red reflectances in the ozone-sensitive variety in August, but did not produce significant reflectance responses in November. Visible reflectance responses to ozone and acidic precipitation, particularly those near 700 nm, were spectrally similar to reflectance responses reported previously for other deleterious environmental influences. C1 AUBURN UNIV,ALABAMA AGR EXPT STN,AUBURN,AL 36849. AUBURN UNIV,SCH FORESTRY,AUBURN,AL 36849. RP CARTER, GA (reprint author), NASA,SCI & TECHNOL LAB,BAY ST LOUIS,MS 39529, USA. NR 45 TC 25 Z9 25 U1 0 U2 4 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0022-0957 J9 J EXP BOT JI J. Exp. Bot. PD APR PY 1992 VL 43 IS 249 BP 577 EP 584 DI 10.1093/jxb/43.4.577 PG 8 WC Plant Sciences SC Plant Sciences GA HP525 UT WOS:A1992HP52500018 ER PT J AU GOLDSTEIN, ME LEIB, SJ COWLEY, SJ AF GOLDSTEIN, ME LEIB, SJ COWLEY, SJ TI DISTORTION OF A FLAT-PLATE BOUNDARY-LAYER BY FREE-STREAM VORTICITY NORMAL TO THE PLATE SO JOURNAL OF FLUID MECHANICS LA English DT Article ID TOLLMIEN-SCHLICHTING WAVES; LEADING-EDGE; EVOLUTION; FLOWS; COLLISION AB We consider a nominally uniform flow over a semi-infinite flat plate. Our analysis shows how a small streamwise disturbance in the otherwise uniform flow ahead of the plate is amplified by leading-edge bluntness effects and eventually leads to a small-amplitude but nonlinear spanwise motion far downstream from the leading edge of the plate. This spanwise motion is then imposed on the viscous boundary-layer flow at the surface of the plate causing an order-one change in its profile shape. This ultimately reduces the wall shear stress to zero causing the boundary layer to undergo a localized separation, which may be characterized as a kind of bursting phenomenon that could be related to the turbulent bursts observed in some flat-plate boundary-layer experiments. C1 SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,BROOK PK,OH 44142. UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,CAMBRIDGE CB3 9EW,ENGLAND. RP GOLDSTEIN, ME (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. RI Cowley, Stephen/D-1856-2009 NR 23 TC 48 Z9 48 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD APR PY 1992 VL 237 BP 231 EP 260 DI 10.1017/S0022112092003409 PG 30 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HT262 UT WOS:A1992HT26200010 ER PT J AU BIRMINGHAM, TJ AF BIRMINGHAM, TJ TI BIRKELAND CURRENTS IN AN ANISOTROPIC, MAGNETOSTATIC PLASMA SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FIELD-ALIGNED CURRENTS; MAGNETOHYDROSTATIC PLASMA; MAGNETIC-FIELDS; REPRESENTATIONS AB An expression for the parallel current density is derived for a plasma characterized by negligible bulk flow (magnetostatic) velocity and a two-component (anisotropic) pressure tensor by expanding the equilibrium Vlasov equation for each species in the adiabatic parameter until such point as a nonvanishing moment j parallel-to = integral d3 upsilon-upsilon parallel-to f is identified. The result is a nonlocal one: it relates j parallel-to at one point s along a field line to j parallel-to at another (reference) point s0 plus an integral function of the pressure and magnetic field between them. It is a generalization and elaboration of results obtained by Bostrom (1975), Heinemann (1990), and Heinemann and Pontius (1991). The expression could have been obtained by integrating the current continuity equation with -del.j perpendicular-to as a source term and j perpendicular-to given by perpendicular momentum balance. We explicitly show the equivalency. The widely used Vasyliunas (1970) equation follows when P perpendicular-to is set equal to P parallel-to and s and s0 are taken to be at the ionosphere and the equator. An extended discussion of the relationship of results derived here to others in the literature is carried out in an effort to bring unity and perspective to this problem area. RP BIRMINGHAM, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. NR 19 TC 24 Z9 24 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 APR 1 PY 1992 VL 97 IS A4 BP 3907 EP 3917 DI 10.1029/91JA03029 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700001 ER PT J AU BIRMINGHAM, TJ AF BIRMINGHAM, TJ TI THE EFFECTS OF PRESSURE ANISOTROPY ON BIRKELAND CURRENTS IN DIPOLE AND STRETCHED MAGNETOSPHERES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article AB The expression for the Birkeland current density in an anisotropic P perpendicular-to, P parallel-to plasma derived in a companion paper (Birmingham, this issue) is simplified by linearization: for purposes of computing j parallel-to the magnetic configuration is assumed to be axisymmetric, either a dipole or a dipole stretched by the field arising from an azimuthal current sheet. The anisotropy is that of a bi-Maxwellian and characterized by equatorial values P perpendicular-to (s0) and r, the equatorial temperature (pressure) ratio. Parameter j parallel-to is proportional to the azimuthal derivatives of P perpendicular-to (s0) and r, with coefficients that are integral functions along the background B of the pressure and field strength from the equator s0, where there is (by assumption) no Birkeland current, to the point of reference. Values of j parallel-to at the ionosphere are compared between the two magnetic models for 0.1 < r < 10., a range that assuredly spans anisotropy ratios likely to be encountered in planetary magnetospheres. The effect of the anisotropy is modest, amounting to a factor of roughly 10 (larger or smaller depending on whether r < 1 or vice versa) for a stretched field line crossing the equator at r0 = 20, less than half this amount for the comparable dipole line. Parameter j parallel-to grows, owing to the diversion of perpendicular currents, rapidly away from the equator, significantly more so for a pressure anisotropy favoring P perpendicular-to (r > 1) than for one favoring P parallel-to (r < 1). The growth away from the equator is particularly steep in the stretched model because of the strong curvature of the field lines, especially at large r0: plasma is trapped in the weak equatorial field, confined on either side by the strong B which arises from the azimuthal current sheet. RP BIRMINGHAM, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. NR 10 TC 6 Z9 6 U1 2 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 APR 1 PY 1992 VL 97 IS A4 BP 3919 EP 3927 DI 10.1029/91JA03030 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700002 ER PT J AU GOLDSTEIN, BE GOLDSTEIN, R NEUGERBAUER, M FUSELIER, SA SHELLEY, EG BALSIGER, H KETTMANN, G IP, WH ROSENBAUER, H SCHWENN, R AF GOLDSTEIN, BE GOLDSTEIN, R NEUGERBAUER, M FUSELIER, SA SHELLEY, EG BALSIGER, H KETTMANN, G IP, WH ROSENBAUER, H SCHWENN, R TI OBSERVATIONS OF PLASMA DYNAMICS IN THE COMA OF P/HALLEY BY THE GIOTTO ION MASS-SPECTROMETER SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND INTERACTION; HALLEY BOW SHOCK; WATER GROUP IONS; MAGNETIC-FIELD; CHARGE-EXCHANGE; SHELL DISTRIBUTION; COMETARY PROTONS; PICKUP IONS; FLOW; COMETOPAUSE AB Observations in the coma of P/Halley by the Giotto ion mass spectrometer (IMS) are reported. The high-energy range spectrometer (HERS) of the IMS obtained measurements of protons and alpha particles from the far upstream region to the near ionopause region and of ions of mass 12-32 at distances of about 250,000 to 40,000 km from the nucleus. Plasma parameters from the high-intensity spectrometer (HIS) of the IMS obtained between 150,000 and 5000 km from the nucleus are also discussed. The distribution functions of water group ions ("water group" will be used to refer to ions of 16-18 m/q, where m is in atomic mass units and q is in unit charges) are observed to be spherically symmetric in velocity space, indicating strong pitch angle scattering. The discontinuity known as the magnetic pileup boundary (MPB) is apparent only in proton, alpha-particle, and magnetometer data, indicating that it is a tangential discontinuity of solar wind origin. HERS observations show no significant change in the properties of the heavy ions across the MPB. The issue of whether a cometopause was unambiguously observed at comet Halley is discussed; it is concluded that the observations do not convincingly support the idea of a boundary due to internal cometary processes (as opposed to convected solar wind discontinuities). A comparison of the observations to MHD models is made. The plasma flow directions at all distances greater than 30,000 km from the nucleus are in agreement with MHD calculations. However, despite the agreement in flow direction, within 200,000 km of the nucleus the magnitude of the velocity is lower than predicted by MHD models, and the density is much larger (a factor of 5 or more for distances 60,000-160,000 km from the comet). Within 30,000 km of the nucleus there are large theoretical differences between the MHD model flow calculations for the plane containing the magnetic field and for the plane perpendicular to the magnetic field. The observations agreed much better with the pattern calculated for the plane perpendicular to the magnetic field. The data obtained by the HERS that are published herein have also been provided to the International Halley Watch archive. C1 UNIV BERN,INST PHYS,CH-3000 BERN,SWITZERLAND. LOCKHEED PALO ALTO RES LABS,DEPT 91-20,PALO ALTO,CA 94304. MAX PLANCK INST AERON,W-3411 KATLENBURG DUHM,GERMANY. RP GOLDSTEIN, BE (reprint author), CALTECH,JET PROP LAB,MAIL STOP 169-506,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 49 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 APR 1 PY 1992 VL 97 IS A4 BP 4121 EP 4132 DI 10.1029/91JA03105 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700018 ER PT J AU FARRELL, WM CURTIS, SA DESCH, MD LEPPING, RP AF FARRELL, WM CURTIS, SA DESCH, MD LEPPING, RP TI A THEORY FOR NARROW-BANDED RADIO-BURSTS AT URANUS - MHD-SURFACE WAVES AS AN ENERGY DRIVER SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID KILOMETRIC RADIATION; POLAR CUSP; CYCLOTRON FREQUENCY; ELECTRON; EMISSION; GROWTH AB We describe a possible scenario for the generation of the narrow-banded radio bursts (n bursts) detected at Uranus by the Voyager 2 planetary radio astronomy experiment. This particular radio emission is suspected to originate within the Uranian northern polar cusp region. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, we propose that ULF magnetic surface turbulence, generated at the frontside magnetopause, propagates down the open/closed field line boundary and mode converts to kinetic Alfven waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream (beam or loss cone) that creates the bursty radio emission. To substantiate these ideas, we show Voyager 2 magnetometer measurements of enhanced ULF magnetic activity at the frontside magnetopause. We then demonstrate analytically that such magnetic turbulence should mode convert deep in the cusp at a radial distance of 3 R(U). A condition for mode conversion from magnetic surface waves to KAW is f(pe)/f(ce) < 0.2, which is also a condition favorable for the generation of the R-X mode radio bursts. The fact that a similar plasma condition is required for both processes lends strong support that the active regions for mode conversion and R-X mode wave generation are one and the same. RP FARRELL, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 30 TC 8 Z9 8 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 APR 1 PY 1992 VL 97 IS A4 BP 4133 EP 4141 DI 10.1029/91JA03143 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700019 ER PT J AU KEATING, GM BOUGHER, SW AF KEATING, GM BOUGHER, SW TI ISOLATION OF MAJOR VENUS THERMOSPHERIC COOLING MECHANISM AND IMPLICATIONS FOR EARTH AND MARS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID THERMAL STRUCTURE; UPPER-ATMOSPHERE; HEAT-BUDGET; EXOSPHERIC TEMPERATURE; GENERAL-CIRCULATION; COUPLED DYNAMICS; LANGMUIR PROBE; CARBON-DIOXIDE; MESOSPHERE; MODEL AB A study of Pioneer Venus orbiter atmospheric drag (OAD) data establishes that there is a weak but clear response of the atmosphere to short-term variations associated with the 27-day rotation of the Sun. Thermospheric temperature residuals relative to the mean diurnal variation have been found to be associated with variations in solar activity after correction for the Earth-Sun-Venus angle. All of the dayside OAD thermospheric data are found to exhibit this characteristic with peak-to-peak temperature variations of approximately 25 K. These results are compared with National Center for Atmospheric Research theoretical models of the Venus thermosphere that include processes not in local thermodynamic equilibrium. It is found that the low amplitude of the 27-day oscillations, combined with the cooling necessary for observed 300-K dayside temperatures, may not be explained by eddy conduction cooling and may only be explained by very strong 15-mu-m cooling. This presumably results from collisional excitation of the (nu(2) = 1) CO2 bending mode by atomic oxygen with subsequent radiation at 15-mu-m. This mechanism is estimated to be 200-1000 times more effective than self-collisions of CO2 and is even more effective since increases in EUV lead to higher O/CO2 ratios. Isolation of this cooling mechanism, which cools the atmosphere from approximately 700 K to 300 K, was only possible through a study of 27-day variations, since the magnitude of 11-year atmospheric variations is very uncertain because of the absence of in situ data near solar minimum. Implications concerning the decrease in amplitude of the 11-year Venus thermospheric variability due to the 15-mu-m thermostat effect are also examined in this paper. The unexpectedly strong radiative cooling mechanism isolated here should also result in substantial cooling of the Earth's mesosphere and thermosphere as CO2 doubles in the next century with even stronger effects than predicted by Roble and Dickinson (1989). The Mars atmosphere should not be as strongly affected by this thermostatic mechanism as Venus' because of the lower O/CO2 ratios on Mars, and thus larger 11-year variations are expected. C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. RP KEATING, GM (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401 B,HAMPTON,VA 23665, USA. RI Bougher, Stephen/C-1913-2013 OI Bougher, Stephen/0000-0002-4178-2729 NR 43 TC 33 Z9 33 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 APR 1 PY 1992 VL 97 IS A4 BP 4189 EP 4197 DI 10.1029/91JA02444 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700023 ER PT J AU BURLAGA, LF AF BURLAGA, LF TI MULTIFRACTAL STRUCTURE OF THE MAGNETIC-FIELD AND PLASMA IN RECURRENT STREAMS AT 1-AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SIGNATURES AB This paper demonstrates the existence of multifractal structure in the fluctuations of the magnetic field strength, temperature, and density in the recurrent flows at 1 AU. The multifractal scaling is observed over the range of periods from 2 hours to 32 hours for the magnetic field and density and from 2 hours to 16 hours for the temperature. The lower cutoff of 2 hours is related to the use of hour averages; it does not have physical significance. The upper cutoff of 32 hours (16 hours) represents the transition to the mesoscale regime in which the fluctuations are determined by the stream structure. Thus the multifractal structure represents fluctuations superimposed on the corotating stream profile and the heliospheric plasma sheet profile. One may think of the multifractal structure as a texture superimposed on the mesoscale profiles, the structure of the texture being related to the mesoscale structure itself. The multifractal structure of the magnetic field strength fluctuations might be produced by a multiplicative process involving the velocity fluctuations. RP BURLAGA, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 24 TC 66 Z9 67 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 APR 1 PY 1992 VL 97 IS A4 BP 4283 EP 4293 DI 10.1029/91JA03027 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700031 ER PT J AU PERKO, JS BURLAGA, LF AF PERKO, JS BURLAGA, LF TI INTENSITY VARIATIONS IN THE INTERPLANETARY MAGNETIC-FIELD MEASURED BY VOYAGER-2 AND THE 11-YEAR SOLAR-CYCLE MODULATION OF GALACTIC COSMIC-RAYS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID OUTER HELIOSPHERE; SPECTRA; SHEET AB We present new evidence to support the hypothesis that the 11-year solar cycle modulation of galactic cosmic rays is caused by strong particle diffusion inside long-lived, merged interaction regions. These regions are represented by local enhancements in the heliospheric magnetic field strength. To test this hypothesis, we solved the one-dimensional, force field approximation of the cosmic ray modulation equation. The only variables were the strength of the local magnetic field and the position of the spacecraft, both taken directly from Voyager 2 data. We assume that a constant solar wind speed convects magnetic field compressions and rarefactions unchanged through a model heliosphere. The result is a reasonable simulation of the integrated, high-energy cosmic ray intensity profile from about 1982 to mid-1989. This period encompasses both the full recovery portion of the last 11-year cosmic ray cycle and the first year and a half of the new cycle. In particular, this model responds to the Voyager 2 magnetic field data by correctly timing the beginning of the new modulation cycle in late 1987. We conclude that our hypothesis is consistent with the results of this simulation. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP PERKO, JS (reprint author), UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716, USA. NR 28 TC 43 Z9 43 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD APR 1 PY 1992 VL 97 IS A4 BP 4305 EP 4308 DI 10.1029/92JA00321 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM067 UT WOS:A1992HM06700034 ER PT J AU KORENFELD, CD GRYMES, RA HOEFFLER, WK BAUER, EA AF KORENFELD, CD GRYMES, RA HOEFFLER, WK BAUER, EA TI THE WERNER SYNDROME COLLAGENASE PROMOTER CONTAINS A NORMAL AP-1 SITE SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DERMATOL,STANFORD,CA 94305. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL PUBLISHING INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 1992 VL 98 IS 4 BP 577 EP 577 PG 1 WC Dermatology SC Dermatology GA HL846 UT WOS:A1992HL84600424 ER PT J AU ALTMAN, J CHAN, J GRYMES, RA BAUER, EA AF ALTMAN, J CHAN, J GRYMES, RA BAUER, EA TI SUPPRESSION OF COLLAGENASE-I EXPRESSION IN PROGERIOD FIBROBLASTS BY HYDROCORTISONE SO JOURNAL OF INVESTIGATIVE DERMATOLOGY LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. STANFORD UNIV,MED CTR,SCH MED,DEPT DERMATOL,STANFORD,CA 94305. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL PUBLISHING INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0022-202X J9 J INVEST DERMATOL JI J. Invest. Dermatol. PD APR PY 1992 VL 98 IS 4 BP 626 EP 626 PG 1 WC Dermatology SC Dermatology GA HL846 UT WOS:A1992HL84600720 ER PT J AU HU, S HOJAJI, H BARKATT, A BOROOMAND, M HUNG, M BUECHELE, AC THORPE, AN DAVIS, DD ALTERESCU, S AF HU, S HOJAJI, H BARKATT, A BOROOMAND, M HUNG, M BUECHELE, AC THORPE, AN DAVIS, DD ALTERESCU, S TI BULK YBA2CU3O(X) SUPERCONDUCTORS THROUGH PRESSURIZED PARTIAL MELT GROWTH PROCESSING SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CRITICAL CURRENTS; GRAIN-BOUNDARIES; PHASE-DIAGRAM; RARE-EARTH; YBA2CU3O7-DELTA; MAGNETIZATION; SYSTEM; FILMS AB We have developed a novel pressurized partial melt growth process for producing large pieces of bulk Y-Ba-Cu-O superconductors. During long-time partial melt growth stage, an additional driving force for solidification is obtained by using pressurized oxygen gas. The microstructure and superconducting properties of the resulting samples were investigated. It was found that this new technique can eliminate porosity and inhomogeneity, promote large-scale grain-texturing, and improve interdomain coupling as well. C1 HOWARD UNIV,WASHINGTON,DC 20059. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP HU, S (reprint author), CATHOLIC UNIV AMER,WASHINGTON,DC 20064, USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1992 VL 7 IS 4 BP 808 EP 812 DI 10.1557/JMR.1992.0808 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA HP370 UT WOS:A1992HP37000007 ER PT J AU DOMIK, GO MICKUSMICELI, KD AF DOMIK, GO MICKUSMICELI, KD TI DESIGN AND DEVELOPMENT OF DATA VISUALIZATION SYSTEMS IN A WORKSTATION ENVIRONMENT SO JOURNAL OF MICROCOMPUTER APPLICATIONS LA English DT Article C1 UNIV COLORADO,DEPT COMP SCI,BOULDER,CO 80309. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 11 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0745-7138 J9 J MICROCOMPUT APPL JI J. Microcomput. Appl. PD APR PY 1992 VL 15 IS 2 BP 81 EP 88 DI 10.1016/0745-7138(92)90051-6 PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA HY103 UT WOS:A1992HY10300001 ER PT J AU VERMOTE, E TANRE, D AF VERMOTE, E TANRE, D TI ANALYTICAL EXPRESSIONS FOR RADIATIVE PROPERTIES OF PLANAR RAYLEIGH-SCATTERING MEDIA, INCLUDING POLARIZATION CONTRIBUTIONS SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID ZONE COLOR SCANNER; ATMOSPHERES AB The objective of this paper is to provide a convenient and fast way for computing the radiative properties of planar Rayleigh scattering media. Analytical expressions are developed for the three molecular atmospheric functions which are required in remote sensing: the atmospheric reflectance, the transmission function and the spherical albedo. The expressions are adjusted by using accurate computations performed with successive orders of a scattering code. The accuracy of the code is first checked by using previously published tabulations. The required accuracy of 0.001 in the reflectance unit is achieved by numerical adjustments. The contribution of polarization is considered implicitly. Our expressions are shown to be valid for a fairly large range of observational conditions. RP VERMOTE, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. RI Vermote, Eric/K-3733-2012 NR 21 TC 30 Z9 31 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD APR PY 1992 VL 47 IS 4 BP 305 EP 314 DI 10.1016/0022-4073(92)90149-X PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA HN255 UT WOS:A1992HN25500009 ER PT J AU MINNETYAN, L CHAMIS, CC MURTHY, PLN AF MINNETYAN, L CHAMIS, CC MURTHY, PLN TI STRUCTURAL BEHAVIOR OF COMPOSITES WITH PROGRESSIVE FRACTURE SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE COMPOSITES; DAMAGE; DEGRADATION; COMPUTATIONAL SIMULATION; LAMINATES; STRUCTURAL RESPONSE AB Structural characteristics such as natural frequencies and buckling loads with corresponding mode shapes were investigated during progressive fracture of multilayer, angle-plied polymer matrix composites. A computer program was used to generate the numerical results for overall mechanical response of damaged composites. Variations in structural characteristics as a function of the previously applied loading were studied. Results indicate that free-vibration and buckling stability properties were preserved throughout a significant proportion of the ultimate fracture load. For the cases studied, changes in structural behavior begin to occur after 70 percent of the ultimate fracture load had been applied. However, the individual nature of the structural change was rather varied depending on the laminate configuration, fiber orientation, and the boundary conditions. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP MINNETYAN, L (reprint author), CLARKSON UNIV,POTSDAM,NY 13699, USA. NR 8 TC 20 Z9 20 U1 0 U2 1 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 0731-6844 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PD APR PY 1992 VL 11 IS 4 BP 413 EP 442 DI 10.1177/073168449201100404 PG 30 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA HP145 UT WOS:A1992HP14500004 ER PT J AU SERAJI, H AF SERAJI, H TI TASK-BASED CONFIGURATION CONTROL OF REDUNDANT MANIPULATORS SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article ID OBSTACLE AVOIDANCE; ROBOTS AB This article establishes new goals for redundancy resolution based on manipulator dynamics and end-effector characteristics. These goals can be accomplished by employing the recently developed configuration control approach. Redundancy resolution is achieved by controlling the joint inertia matrix or the end-effector mass matrix that affect the inertial torques or by reducing the joint torques due to gravity loading and payload. The manipulator mechanical advantage and velocity ratio are also used as performance measures to be improved by proper utilization of redundancy. Furthermore, end-effector compliance, sensitivity, and impulsive force at impact are introduced as redundancy-resolution criteria. The new goals for redundancy resolution presented in this article allow a more efficient utilization of the redundant joints based on the desired task requirements. Simple case studies using computer simulations are described for illustration. RP SERAJI, H (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 20 TC 15 Z9 15 U1 0 U2 1 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 APR PY 1992 VL 9 IS 3 BP 411 EP 451 DI 10.1002/rob.4620090307 PG 41 WC Robotics SC Robotics GA HL405 UT WOS:A1992HL40500006 ER PT J AU MOORTY, S ROEDER, CW AF MOORTY, S ROEDER, CW TI TEMPERATURE-DEPENDENT BRIDGE MOVEMENTS SO JOURNAL OF STRUCTURAL ENGINEERING-ASCE LA English DT Article AB The response of bridges exposed to thermal environment conditions is studied. Analytical methods are developed to obtain temperature distributions and the maximum bridge temperature ranges. Thermoelastic analysis is conducted to obtain the temperature induced movements and the associated stresses in bridges. Parametric studies are conducted for different bridge geometries, temperature distributions, and support conditions. A field test is conducted on a bridge to verify the analytical models. The analysis suggests that concrete bridges sometimes are designed for smaller temperature ranges and corresponding thermal movements than may be expected in practice. The analysis suggests that steel bridges with composite concrete decks sometimes are designed for larger temperature ranges and thermal movements than may be expected at many locations in the United States. Skew and curved bridges often exhibit magnitude and direction of movement that is different than commonly expected. Additional guidelines and recommendations are provided regarding the analysis required to accurately predict thermal movements and the placement of bearings and expansion joints. This study will help engineers better understand thermal movements and stresses developed in bridges. C1 UNIV WASHINGTON,DEPT CIVIL ENGN,SEATTLE,WA 98195. RP MOORTY, S (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 11 TC 44 Z9 53 U1 2 U2 8 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9445 J9 J STRUCT ENG-ASCE JI J. Struct. Eng.-ASCE PD APR PY 1992 VL 118 IS 4 BP 1090 EP 1105 DI 10.1061/(ASCE)0733-9445(1992)118:4(1090) PG 16 WC Construction & Building Technology; Engineering, Civil SC Construction & Building Technology; Engineering GA HK133 UT WOS:A1992HK13300014 ER PT J AU FOGELSANGER, P AF FOGELSANGER, P TI SELECTING THE RIGHT TOOLS FOR CLIENT SERVER - A NASA PERSPECTIVE SO JOURNAL OF SYSTEMS MANAGEMENT LA English DT Article AB Many articles have been written about client/server technology. Most of the effort, however, has been exhausted evaluating each new graphical user interface (GUI) front-end that arrives on the market. There has also been much said about the performance of various data base management systems (DBMSs). Very little, on the other hand, has been written about the key criteria that should be used when selecting the proper tools for developing a client/server application. This article's purpose is to be more practical by outlining the primary criteria to use when comparing DBMS products and GUIs. It draws from the recent experience at the U.S. National Aeronautics and Space Administration (NASA) in evaluating a move to a client/server architecture. RP FOGELSANGER, P (reprint author), COMP BASED SYST,NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20770, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC SYSTEMS MANAGEMENT PI CLEVELAND PA 24587 BAGLEY RD, CLEVELAND, OH 44138 SN 0022-4839 J9 J SYST MANAGE PD APR PY 1992 VL 43 IS 4 BP 23 EP 27 PG 5 WC Computer Science, Theory & Methods; Management SC Computer Science; Business & Economics GA HN507 UT WOS:A1992HN50700007 ER PT J AU MARCOLINI, MA BROOKS, TF AF MARCOLINI, MA BROOKS, TF TI ROTOR NOISE MEASUREMENT USING A DIRECTIONAL MICROPHONE ARRAY SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB A directional array of microphones was used to measure the noise from a 40 percent scale model rotor in a large aeroacoustic wind tunnel. The development and design of this multi-element array is described. A design goal was that the array focus on a constant sensing area over a broad frequency range. This was accomplished by blending three concentric 4-element circular arrays. The implementation of the array design is presented, followed by sample results for several different rotor test conditions. The directional array spectral results are compared with predictions of broadband self noise, and with total rotor noise measurements obtained from individual microphones of the array. Good agreement was obtained, thus demonstrating that the directional array can be a useful tool in examining noise source distributions. RP MARCOLINI, MA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 15 TC 4 Z9 5 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 APR PY 1992 VL 37 IS 2 BP 11 EP 22 PG 12 WC Engineering, Aerospace SC Engineering GA HU567 UT WOS:A1992HU56700002 ER PT J AU LIGHT, JS SWANSON, AA NORMAN, TR AF LIGHT, JS SWANSON, AA NORMAN, TR TI APPLICATION OF THE WIDE-FIELD SHADOWGRAPH TECHNIQUE TO HELICOPTERS IN FORWARD FLIGHT SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB A test was conducted to examine the feasibility of using the wide-field shadowgraph method for visualizing the wake of a small-scale helicopter rotor in forward flight. A wide range of test conditions was examined, including thrust and forward speed variations. Shadowgraphs from the side and top of the rotor were obtained. The visibility of the tip vortices using the shadowgraph method was documented for advance ratios up to 0.175. It was demonstrated that shadowgraphs can be used to obtain qualitative and quantitative information about wake geometry, wake/body interactions, and blade/vortex interactions in forward flight. Video cameras were used for the first time to record the shadowgraphs. These provided several advantages compared to still cameras, and greatly enhance the capabilities of the shadowgraph method. C1 STERLING FED SYST INC,MOFFETT FIELD,CA. RP LIGHT, JS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 9 TC 3 Z9 3 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 APR PY 1992 VL 37 IS 2 BP 23 EP 28 PG 6 WC Engineering, Aerospace SC Engineering GA HU567 UT WOS:A1992HU56700003 ER PT J AU KELLEY, HL CROWELL, CA YENNI, KR LANCE, MB AF KELLEY, HL CROWELL, CA YENNI, KR LANCE, MB TI FLIGHT INVESTIGATION OF THE EFFECT OF TAIL BOOM STRAKES ON HELICOPTER DIRECTIONAL CONTROL SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB A joint U.S. Army/NASA flight investigation was conducted utilizing an instrumented Bell 204B single-rotor helicopter to determine the effectiveness of horizontally-mounted tail boom strakes on directional controllability and tail rotor power during low-speed, crosswind operating conditions. The purpose of the strakes was to separate airflow over the tail boom, thus improving yaw control margin and reducing tail rotor power. Crosswind data were obtained in 5-knot increments at airspeeds of 0 knots to 35 knots and for 30 deg increments in wind azimuth from 0 deg to 330 deg. At the most critical wind azimuth and airspeed (60 deg azimuth measured from the nose of the aircraft and 20 knots airspeed), the strakes improved the pedal margin by 6 percent of total travel and reduced the tail rotor power by 17 percent. Improvements of this order can expand the operating envelope in terms of gross weight and altitude capability. No adverse effects in high-speed forward flight were noted. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA. RP KELLEY, HL (reprint author), NASA,LANGLEY RES CTR,AVIAT SYST COMMAND,AEROSTRUCT DIRECTORATE,HAMPTON,VA 23665, USA. NR 26 TC 6 Z9 6 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 APR PY 1992 VL 37 IS 2 BP 29 EP 40 PG 12 WC Engineering, Aerospace SC Engineering GA HU567 UT WOS:A1992HU56700004 ER PT J AU EVERETT, RA BARTLETT, FD ELBER, W AF EVERETT, RA BARTLETT, FD ELBER, W TI PROBABILISTIC FATIGUE METHODOLOGY FOR SAFE RETIREMENT LIVES SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB Fleet readiness and flight safety strongly depend on the degree of reliability and maintainability that can be designed into rotorcraft flight critical components. The current U.S. Army fatigue life specification for new rotorcraft is the so-called "six nines" reliability, or a probability of failure of one in a million. This report reviews the progress of a round robin which was established by the American Helicopter Society (AHS) Subcommittee for Fatigue and Damage Tolerance to investigate reliability-based fatigue methodology. The participants in this cooperative effort are the U.S. Army Aviation Systems Command (AVSCOM) and the rotorcraft industry. One phase of the joint activity examined fatigue reliability under uniquely defined conditions for which only one answer was correct. The other phases were set up to learn how the different industry methods in defining fatigue strength affected the mean fatigue life and reliability calculations. Hence, constant amplitude and spectrum fatigue test data were provided so that each participant could perform their standard fatigue life analysis. As a result of this round robin, the probabilistic logic for including both fatigue strength and spectrum loading variability to develop a consistent reliability analysis was established. In this first study, the reliability analysis was limited to the linear cumulative damage approach. However, it is expected that superior fatigue life prediction methods will ultimately be developed through this open AHS forum. To that end, these preliminary results were useful in identifying some topics for additional study. RP EVERETT, RA (reprint author), LANGLEY RES CTR,USA,AVSCOM,AEROSTRUCT DIRECTORATE,DIV STRUCT,HAMPTON,VA, USA. NR 12 TC 4 Z9 4 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 APR PY 1992 VL 37 IS 2 BP 41 EP 53 PG 13 WC Engineering, Aerospace SC Engineering GA HU567 UT WOS:A1992HU56700005 ER PT J AU EVERETT, RA AF EVERETT, RA TI A COMPARISON OF FATIGUE LIFE PREDICTION METHODOLOGIES FOR ROTORCRAFT SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article AB Because of the current U.S. Army requirement that all new rotorcraft be designed to a "six nines" reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgren-Miner linear cumulative damage rule to predict the fatigue life of rotocraft dynamic components. It has been shown in the past that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (K(T) = 2.42) specimens made of 4340 steel using the Felix/28 variable amplitude spectrum (a shortened form of a standard loading sequence for 'fixed' or semi-rigid helicopter rotors). Two other spectra which resulted from a simple rainflow reconstruction of Felix/28 were also tested. Both linear cumulative damage methods predicted the fatigue lives of the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on "small-crack" crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer than the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra. RP EVERETT, RA (reprint author), LANGLEY RES CTR,USA,AVSCOM,AEROSTRUCT DIRECTORATE,HAMPTON,VA, USA. NR 17 TC 2 Z9 2 U1 0 U2 1 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 APR PY 1992 VL 37 IS 2 BP 54 EP 60 PG 7 WC Engineering, Aerospace SC Engineering GA HU567 UT WOS:A1992HU56700006 ER PT J AU HANSON, JM EVANS, MJ TURNER, RE AF HANSON, JM EVANS, MJ TURNER, RE TI DESIGNING GOOD PARTIAL COVERAGE SATELLITE CONSTELLATIONS SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB Design of satellite constellations providing partial coverage of certain regions is becoming more important as small low-altitude satellites receive increased attention. The purpose of this study is to develop the procedures necessary for deriving the best constellations for partial coverage. The term best is defined here as the minimum number of satellites at the minimum possible inclination with the smallest possible maximum time gap. This paper analyzes circular orbit constellations and shows that repeating ground track orbits yield better results than non-repeating ground track orbits. This theory provides methods for designing the best constellations. Results, comparing the new, non-standard satellite constellations with the best standard designs, show the new designs generally yield better results and require significantly less computation. Results are given for ground points at different latitudes, different minimum elevation angles for viewing a ground point, different satellite altitudes, and various gap time requirements. The paper develops theory for extending the methods to minimum pass time duration requirements and to coverage of extended areas. Results are presented in these cases. The new methods will potentially save money in satellite production and launch costs and allow for increased coverage capabilities. C1 ANSER CORP,DIV SPACE SYST,ARLINGTON,VA. RP HANSON, JM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 13 TC 17 Z9 19 U1 2 U2 3 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 1992 VL 40 IS 2 BP 215 EP 239 PG 25 WC Engineering, Aerospace SC Engineering GA HZ480 UT WOS:A1992HZ48000004 ER PT J AU HAMPTON, RD GRODSINSKY, CM ALLAIRE, PE LEWIS, DW KNOSPE, CR AF HAMPTON, RD GRODSINSKY, CM ALLAIRE, PE LEWIS, DW KNOSPE, CR TI OPTIMAL MICROGRAVITY VIBRATION ISOLATION - AN ALGEBRAIC INTRODUCTION SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB Certain experiments contemplated for space platforms must be isolated from the accelerations of the platform. In this paper an optimal active control is developed for microgravity vibration isolation, using constant state feedback gains (identical to those obtained from the Linear Quadratic Regulator [LQR] approach) along with constant feedforward (preview) gains. The quadratic cost function for this control algorithm effectively weights accelerations of the platform due to external disturbances by a factor proportional to (1/omega)2. Low frequency accelerations (less than 50 Hz) are attenuated by greater than two orders of magnitude. The control relies on the absolute position and velocity feedback of the experiment and the absolute position and velocity feed-forward of the platform, and generally derives the stability robustness characteristics guaranteed by the LQR approach to optimality. The method as derived is extendable to the case in which only the relative positions and the absolute accelerations of the experiment and space platform are available. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP HAMPTON, RD (reprint author), UNIV VIRGINIA,DEPT MECH & AEROSP ENGN,CHARLOTTESVILLE,VA 22901, USA. NR 16 TC 3 Z9 3 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 1992 VL 40 IS 2 BP 241 EP 259 PG 19 WC Engineering, Aerospace SC Engineering GA HZ480 UT WOS:A1992HZ48000005 ER PT J AU PHAN, M JUANG, JN LONGMAN, RW AF PHAN, M JUANG, JN LONGMAN, RW TI IDENTIFICATION OF LINEAR-MULTIVARIABLE SYSTEMS BY IDENTIFICATION OF OBSERVERS WITH ASSIGNED REAL EIGENVALUES SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB This paper presents a formulation for identification of linear multivariable systems from a single set of input-output data. This approach contrasts with an existing learning approach that requires data from multiple experiments. In this method, the system input-output relationship is expressed in terms of an observer, which is made asymptotically stable by an embedded real eigenvalue assignment procedure. First, the Markov parameters of the observer are identified. Second, the Markov parameters of the actual system are recovered from those of the observer, and used to obtain a state space model of the system. The basic mathematical formulation is derived, and numerical examples presented to illustrate the proposed method. C1 NASA,LANGLEY RES CTR,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23665. COLUMBIA UNIV,MECH ENGN,NEW YORK,NY 10027. RP PHAN, M (reprint author), LOCKHEED ENG & SCI CO,HAMPTON,VA, USA. NR 15 TC 18 Z9 18 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD APR-JUN PY 1992 VL 40 IS 2 BP 261 EP 279 PG 19 WC Engineering, Aerospace SC Engineering GA HZ480 UT WOS:A1992HZ48000006 ER PT J AU WU, MLC AF WU, MLC TI GLOBAL MEAN LONG-WAVE CLOUD RADIATIVE FORCING DERIVED FROM HIRS2/MSU SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Note AB Using a physical approach, global ten-day mean long-wave cloud radiative forcing has been derived from satellite data for a period from January 1979 to May 1981. This forcing shows small (2 to 3 Wm-2) variations for diurnal, seasonal and inter-annual time scales, even though the detailed structure of cloud fields may have considerable temporal and spatial variability. The amplitude of variations of the hemispheric mean is much larger than the global mean; the largest variation is over land areas (20 Wm-2) of the Southern Hemisphere and the smallest variation is over the ocean (6 Wm-2) of the Northern Hemisphere. RP WU, MLC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD APR PY 1992 VL 70 IS 2 BP 723 EP 731 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HX647 UT WOS:A1992HX64700005 ER PT J AU MULLIGAN, JB AF MULLIGAN, JB TI ANISOTROPY IN AN AMBIGUOUS KINETIC DEPTH EFFECT SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID MOTION; ORIENTATION; PERCEPTION; IMAGE; FLOW AB A set of animated stimuli (Lissajous figures), each element of which is physically consistent with two different three-dimensional shapes undergoing rigid rotations about orthogonal axes, is described. Human observers typically show a preference for one shape or the other; this preference may be biased by manipulating various parameters of the stimulus. Fairly good predictions of which shape will be seen are made by using an adaptation of Hildreth's smoothest-velocity-field computation. When a given stimulus is rotated 90-degrees in the picture plane, the resolution of the ambiguity is often different, demonstrating anisotropy in the processing of the figures. The nature of this bias is such that for certain figures subjects see a three-dimensional object rotating about a vertical axis regardless of which two-dimensional orientation is used to present the stimulus. This bias is not predicted by the Hildreth model. One interpretation of the results is that the ambiguity in two-dimensional visual motion (i.e., the aperture problem) is not resolved before the interpretation of the three-dimensional structure. RP MULLIGAN, JB (reprint author), NASA,AMES RES CTR,DIV AEROSP HUMAN FACTORS RES,MS 262-2,MOFFETT FIELD,CA 94035, USA. FU NEI NIH HHS [EY-01711] NR 22 TC 6 Z9 6 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD APR PY 1992 VL 9 IS 4 BP 521 EP 529 DI 10.1364/JOSAA.9.000521 PG 9 WC Optics SC Optics GA HK847 UT WOS:A1992HK84700003 PM 1569494 ER PT J AU TOTH, RA AF TOTH, RA TI HIGH-RESOLUTION MEASUREMENTS AND ANALYSIS OF (NO2)-N-14-O-16 IN THE (001)-(000) AND (011)-(010) BANDS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID ROTATION PARAMETERS; INFRARED-SPECTRUM; SPIN-ROTATION; GROUND-STATE; NU-2 BAND; NO2; SPECTROSCOPY; RESONANCE; STRENGTHS AB High-resolution spectra of NO2 were recorded with a Fourier-transform spectrometer, covering transitions in the (001)-(000) and (011)-(010) bands from 1540 to 1662 cm-1. The measured line frequencies were used with additional data taken from studies at microwave and far-IR frequencies in an analysis to obtain spin-rotation constants and rotational energies of levels in the (001) and (011) states. Line strengths of these two bands were also measured and analyzed in this study. The analyses included spin-rotation levels of the (001) state for K(a) up to and including 13 and N to 73 and those of the (001) state for K(a) up to and including 7 and N to 55. The study included observed and enhanced K(a) = 5 --> 6 transitions in the (020)-(000) band that interact, by means of a Coriolis-type interaction, with K(a) = 5 transitions in the (011)-(000) band. Also observed and analyzed were the results of spin-rotation resonance interactions between two levels of the same state. These perturbations affected one or more levels of a given K(a) and state and were observed for K(a) = 0 with K(a) = 2 and K(a) = 1 with K(a) = 3 for the (001) and (000) states and for K(a) = 0 with K(a) = 2 for the (011) and (001) states. RP TOTH, RA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 26 TC 21 Z9 21 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1992 VL 9 IS 4 BP 433 EP 461 DI 10.1364/JOSAB.9.000433 PG 29 WC Optics SC Optics GA HM686 UT WOS:A1992HM68600001 ER PT J AU TOTH, RA AF TOTH, RA TI TRANSITION FREQUENCIES AND ABSOLUTE STRENGTHS OF (H2O)-O-17 AND (H2O)-O-18 IN THE 6.2-MU-M REGION SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID MICROWAVE-SPECTRUM; INTENSITIES; H2O-17 AB High-resolution spectra of oxygen-enriched samples of water vapor were recorded with a Fourier-transform spectrometer covering transitions in the (010)-(000) bands. The measured line frequencies were used along with measurements taken from studies at microwave and far-infrared frequencies to obtain rotational energy levels in the (000) and (010) states of (H2O)-O-17 and (H2O)-O-18. Measurements of the line strengths were fitted to a model in which as many as 18 transition moment parameters were determined. The results produced computed line-strength values that are in excellent agreement with the 623 (H2O)-O-17 experimental transition strengths and 696 (H2O)-O-18 values. These results provide a more accurate representation of the line positions and strengths for the (010)-(000) bands of (H2O)-O-17 and (H2O)-O-18 those previously available. RP TOTH, RA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 16 TC 48 Z9 48 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD APR PY 1992 VL 9 IS 4 BP 462 EP 482 DI 10.1364/JOSAB.9.000462 PG 21 WC Optics SC Optics GA HM686 UT WOS:A1992HM68600002 ER PT J AU TAUBER, ME PALMER, GE YANG, L AF TAUBER, ME PALMER, GE YANG, L TI EARTH ATMOSPHERIC ENTRY STUDIES FOR MANNED MARS MISSIONS SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB The lift/drag ratios (L/Ds) required, and the decelerations, heating rates, and total heat loads encountered when returning from Mars to Earth at entry speeds of 12 km/s to 16 km/s are studied. An entry velocity of 14 km/s is emphasized because it is the fastest entry presently envisioned for manned missions. For entry at 14 km/s, it is found that an L/D of 0.5 is required to provide a guidance corridor margin near 1 deg for the specified deceleration limit of 5 g. The L/D of 0.3 of the Apollo shape is found to be inadequate. The stagnation point peak heating rates range from about 0.87 kW/cm2 for the overshoot trajectory to 1.33 kW/cm2 at undershoot, for a ballistic coefficient of 300 kg/m2. For a blunted, raked cone with an L/D = 0.5, the peak heating rate near the aft end of the forebody varies from 0.14 to 0.23 kW/cm2 for laminar flow; but if ablation triggers boundary-layer transition, the peak heating can rise to 0.5 or up to 0.72 kW/cm2. All heating rates are sufficiently high to make ablative heat shields necessary. The stagnation point total heat load is about 100 kJ/cm2. The total heat loads near the aft end of the forebody are about 20 kJ/cm2 for a laminar boundary layer; the heat load approaches 90 kJ/cm2 if fully turbulent flow is assumed during the entire entry. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. STERLING SOFTWARE, PALO ALTO, CA 94303 USA. NR 20 TC 5 Z9 5 U1 2 U2 4 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 APR-JUN PY 1992 VL 6 IS 2 BP 193 EP 199 DI 10.2514/3.345 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HX493 UT WOS:A1992HX49300001 ER PT J AU PANDEY, AK DECHAUMPHAI, P WIETING, AR AF PANDEY, AK DECHAUMPHAI, P WIETING, AR TI THERMAL-STRUCTURAL FINITE-ELEMENT ANALYSIS USING LINEAR FLUX FORMULATION SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article AB A linear flux approach is developed for a finite element thermal-structural analysis of steady-state thermal and structural problems. The element fluxes are assumed to vary linearly in the same form as the element unknown variables, and the finite element matrices are evaluated in closed form. Because numerical integration is avoided, significant computational time-saving is achieved. Solution accuracy and computational speed improvements are demonstrated by solving several two- and three-dimensional thermal-structural examples. C1 LOCKHEED ENGN & SCI CO, HAMPTON, VA 23666 USA. NASA, LANGLEY RES CTR, AEROTHERMAL LOADS BRANCH, HAMPTON, VA 23665 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 1992 VL 6 IS 2 BP 341 EP 348 DI 10.2514/3.365 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HX493 UT WOS:A1992HX49300021 ER PT J AU WANG, LW CHAI, AT SUN, DJ AF WANG, LW CHAI, AT SUN, DJ TI CONVECTIVE FLOWS IN ENCLOSURES WITH VERTICAL TEMPERATURE OR CONCENTRATION GRADIENTS SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Note C1 YUAN ZE INST TECHNOL, CHUNGLI 32026, TAIWAN. NATL CHENG KUNG UNIV, TAINAN 70102, TAIWAN. NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD APR-JUN PY 1992 VL 6 IS 2 BP 379 EP 381 DI 10.2514/3.371 PG 3 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HX493 UT WOS:A1992HX49300027 ER PT J AU HATHAWAY, MD WOOD, JR WASSERBAUER, CA AF HATHAWAY, MD WOOD, JR WASSERBAUER, CA TI NASA LOW-SPEED CENTRIFUGAL-COMPRESSOR FOR 3-DIMENSIONAL VISCOUS CODE ASSESSMENT AND FUNDAMENTAL FLOW PHYSICS RESEARCH SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article AB A low-speed centrifugal compressor facility recently built by the NASA Lewis Research Center is described. The purpose of this facility is to obtain detailed flow field measurements for computational fluid dynamic code assessment and flow physics modeling in support of Army and NASA efforts to advance small gas turbine engine technology. The facility is heavily instrumented with pressure and temperature probes, in both the stationary and rotating frames of reference, and has provisions for flow visualization and laser velocimetry. The facility will accommodate rotational speeds to 2400 rpm and is rated at pressures to 1.25 atm. The initial compressor stage being tested is geometrically and dynamically representative of modern high-performance centrifugal compressor stages with the exception of Mach number levels. Preliminary experimental investigations of inlet and exit flow uniformity and measurement repeatability are presented. These results demonstrate the high quality of the data that may be expected from this facility. The significance of synergism between computational fluid dynamic analyses and experimentation throughout the development of the low-speed centrifugal compressor facility is demonstrated. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,CLEVELAND,OH 44135. RP HATHAWAY, MD (reprint author), USA AVIAT SYST COMMAND,PROPULS DIRECTORATE,CLEVELAND,OH 44135, USA. NR 16 TC 5 Z9 5 U1 1 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD APR PY 1992 VL 114 IS 2 BP 295 EP 303 DI 10.1115/1.2929143 PG 9 WC Engineering, Mechanical SC Engineering GA HR907 UT WOS:A1992HR90700004 ER PT J AU LEPICOVSKY, J AF LEPICOVSKY, J TI AN EXPERIMENTAL INVESTIGATION OF NOZZLE-EXIT BOUNDARY-LAYERS OF HIGHLY HEATED FREE JETS SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article AB An experimental investigation of the effects of nozzle operating conditions on the development of nozzle-exit boundary layers of highly heated air free jets is reported in this paper. The total pressure measurements in the nozzle-exit boundary layer were obtained at a range of jet Mach numbers from 0.1 to 0.97 and jet total temperatures up to 900 K. The analysis of results shows that the nozzle-exit laminar boundary-layer development depends only on the nozzle-exit Reynolds number. For the nozzle-exit turbulent boundary layer, however, it appears that the effects of the jet total temperature on the boundary-layer integral characteristics are independent from the effect of the nozzle-exit Reynolds number. This surprising finding has not yet been reported. Further, laminar boundary-layer profiles were compared with the Pohlhausen solution for a flat-wall converging channel and an acceptable agreement was found only for low Reynolds numbers. For turbulent boundary layers, the dependence of the shape factor on relative Mach numbers at a distance of one momentum thickness from the nozzle wall resembles Spence's prediction. Finally, the calculated total pressure loss coefficient was found to depend on the nozzle-exit Reynolds number for the laminar nozzle-exit boundary layer, while for the turbulent exit boundary layer this coefficient appears to be constant. RP LEPICOVSKY, J (reprint author), SVERDRUP TECHNOL INC,NASA,LEWIS RES CTR GRP,BROOK PK,OH 44142, USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD APR PY 1992 VL 114 IS 2 BP 469 EP 475 DI 10.1115/1.2929167 PG 7 WC Engineering, Mechanical SC Engineering GA HR907 UT WOS:A1992HR90700026 ER PT J AU RIZZI, SA DOYLE, JF AF RIZZI, SA DOYLE, JF TI SPECTRAL-ANALYSIS OF WAVE MOTION IN PLANE SOLIDS WITH BOUNDARIES SO JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME LA English DT Article AB A spectral formulation is employed whereby in-plane stress waves are synthesized from the superposition of components at discrete frequencies and wavenumbers. The summations are performed using the fast Fourier transform and the Fourier series, respectively. Because the components are discrete, the solution to problems (over the entire field) with completely arbitrary loading, both in time and space, is made tractable. Waves generated from a line load acting on an infinite and semi-infinite plane are first considered. A cascade approach is then adopted for the treatment of these waves incident on a free, fixed, and elastic boundary. At each stage, the results are compared with those obtained from the available classical solutions and/or finite element results. These studies will form the basis for the investigation of in-plane stress waves in multiply layered media. RP RIZZI, SA (reprint author), NASA,LANGLEY RES CTR,STRUCT ACOUST BRANCH,HAMPTON,VA 23665, USA. NR 0 TC 19 Z9 24 U1 2 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1048-9002 J9 J VIB ACOUST JI J. Vib. Acoust.-Trans. ASME PD APR PY 1992 VL 114 IS 2 BP 133 EP 140 DI 10.1115/1.2930241 PG 8 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA HQ008 UT WOS:A1992HQ00800001 ER PT J AU NOEVER, DA AF NOEVER, DA TI STATISTICAL CRYSTALLOGRAPHY OF SURFACE MICELLE SPACING SO LANGMUIR LA English DT Letter ID MONOLAYERS; DYNAMICS AB The aggregation of the recently reported surface micelles of block polyelectrolytes1,2 is analyzed using techniques of statistical crystallography. A polygonal lattice (Voronoi mosaic) connects center-to-center points, yielding statistical agreement with crystallographic predictions; Aboav-Weaire's law and Lewis's law are verified. This protocol supplements the standard analysis of surface micelles2 leading to aggregation number determination and, when compared to numerical simulations, allows further insight into the random partitioning of surface films. In particular, agreement with Lewis's law has been linked to the geometric packing requirements of filling two-dimensional space which compete with (or balance) physical forces such as interfacial tension, electrostatic repulsion, and van der Waals attraction. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES-76,HUNTSVILLE,AL 35812, USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR PY 1992 VL 8 IS 4 BP 1036 EP 1038 DI 10.1021/la00040a002 PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA HP262 UT WOS:A1992HP26200002 ER PT J AU ALLARIO, F ANTCUFF, RR BROCKMAN, P THOMAS, ME AF ALLARIO, F ANTCUFF, RR BROCKMAN, P THOMAS, ME TI LASER REMOTE-SENSING SUPPORTS AVIATION RESEARCH AND SAFETY SO LASER FOCUS WORLD LA English DT Article RP ALLARIO, F (reprint author), NASA,LANGLEY RES CTR,ELECTR,HAMPTON,VA 23665, USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD APR PY 1992 VL 28 IS 4 BP 58 EP & PG 0 WC Optics SC Optics GA HP506 UT WOS:A1992HP50600021 ER PT J AU SACHSE, GW BROWELL, EV AF SACHSE, GW BROWELL, EV TI AIRBORNE LASERS ACCURATELY MEASURE GREENHOUSE GASES SO LASER FOCUS WORLD LA English DT Article ID CARBON-MONOXIDE; AMAZON BASIN C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23665. RP SACHSE, GW (reprint author), NASA,LANGLEY RES CTR,DIV FLIGHT ELECTR,ATMOSPHER GRP,HAMPTON,VA 23665, USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD APR PY 1992 VL 28 IS 4 BP 73 EP 74 PG 2 WC Optics SC Optics GA HP506 UT WOS:A1992HP50600022 ER PT J AU KUMAR, KS WHITTENBERGER, JD AF KUMAR, KS WHITTENBERGER, JD TI DISCONTINUOUSLY REINFORCED INTERMETALLIC MATRIX COMPOSITES VIA XD SYNTHESIS SO MATERIALS SCIENCE AND TECHNOLOGY LA English DT Article ID PLASTIC-FLOW PROPERTIES; GRAIN-SIZE; TITANIUM ALUMINIDE; PARTICULATE COMPOSITES; NIAL-TIB2 COMPOSITES; COMPRESSION BEHAVIOR; DUCTILE TRANSITION; FRACTURE-TOUGHNESS; ELASTIC-MODULUS; BRITTLE AB A review is given of recent results obtained for discontinuously reinforced intermetallic matrix composites produced using the XD process. Intermetallic matrixes investigated include NiAl, multiphase NiAl + Ni2AlTi, CoAl, near gamma-titanium aluminides (i.e. TiAl + Ti3Al), and L1(2) trialuminides containing minor amounts of second phase. A judicious match of the matrix and reinforcement can enhance both physical and mechanical properties. Particulate reinforcements can affect properties directly by enhancing modulus and strength or indirectly by refining grain size, enhancing microstructural homogeneity in a casting, or providing additional nucleation sites which improve phase transformation kinetics. Such mechanical properties as low and high temperature strength, compressive and tensile creep, elastic modulus, ambient ductility, and fracture toughness are discussed as functions of reinforcement size, shape, and volume fraction. Microstructures before and after deformation are examined and correlated with measured properties. An observation of interest in many of the systems examined is 'dispersion weakening' at high temperatures and high strain rates. This behaviour is not specific to the XD process; rather similar observations have been reported in other discontinuous composites. Proposed mechanisms for this behaviour are presented. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP KUMAR, KS (reprint author), MARTIN MARIETTA CORP LABS,BALTIMORE,MD 21227, USA. NR 72 TC 44 Z9 45 U1 0 U2 3 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5DB SN 0267-0836 J9 MATER SCI TECH SER JI Mater. Sci. Technol. PD APR PY 1992 VL 8 IS 4 BP 317 EP 330 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HY786 UT WOS:A1992HY78600005 ER PT J AU JOHNSTON, S LYNE, AG MANCHESTER, RN KNIFFEN, DA DAMICO, N LIM, J ASHWORTH, M AF JOHNSTON, S LYNE, AG MANCHESTER, RN KNIFFEN, DA DAMICO, N LIM, J ASHWORTH, M TI A HIGH-FREQUENCY SURVEY OF THE SOUTHERN GALACTIC PLANE FOR PULSARS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article ID MILLISECOND PULSARS; MOLONGLO; SEARCH; YOUNG AB We report the results of a high-frequency survey designed to detect young, distant and short-period pulsars. The Parkes 64-m radio telescope was used at a central observing frequency of 1500 MHz to survey an area of 800 square degrees in the region 270-degrees less-than-or-equal-to l less-than-or-equal-to 20-degrees, \b\ less-than-or-equal-to 4-degrees. To ensure that the system retained good sensitivity to periods of less than 10 ms, we used sampling intervals of 0.3 and 1.2 ms. The survey detected a total of 100 pulsars, 46 of which were previously unknown. The periods of the newly discovered pulsars range between 47 ms and 2.5 s. One of the new discoveries, PSR 1259-63, is a member of a long-period binary system. At least three of the pulsars have ages less than 30 000 yr, bringing the total number of such pulsars to 12. PSR 1112-60 is probably embedded in the powerful H II region RCW 57. The majority of the new discoveries are distant objects with high dispersion measures, which are difficult to detect at low frequencies. This demonstrates that the survey has reduced the severe selection effects of pulse scattering, high Galactic background temperature and dispersion broadening, which hamper the detection of such pulsars at low radio frequencies. This survey complements a similar survey of the northern Galactic plane undertaken by Clifton & Lyne. The pulsar distribution in the southern Galaxy is found to extend much further from the Galactic Centre than that in the north, probably due to two prominent spiral arms in the southern Galaxy. C1 UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. MACQUARIE UNIV,SCH MATH PHYS COMP & ELECTR,N RYDE,NSW 2113,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV PALERMO,IST FIS,I-90134 PALERMO,ITALY. UNIV MANCHESTER,MANCHESTER COMP CTR,MANCHESTER M13 9PL,LANCS,ENGLAND. CNR,IST RADIOASTRON,I-40126 BOLOGNA,ITALY. RP JOHNSTON, S (reprint author), CSIRO,AUSTRALIA TELESCOPE NATL FACIL,POB 76,EPPING,NSW 2121,AUSTRALIA. RI D'Amico, Nichi/A-5715-2009 NR 23 TC 188 Z9 190 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1992 VL 255 IS 3 BP 401 EP 411 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HL902 UT WOS:A1992HL90200005 ER PT J AU SKINNER, CJ BARLOW, MJ JUSTTANONT, K AF SKINNER, CJ BARLOW, MJ JUSTTANONT, K TI SILICATE DUST IN A VEGA-EXCESS SYSTEM SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Note DE CIRCUMSTELLAR MATTER; STARS, INDIVIDUALS, SAO-179815; DUST, EXTINCTION; INFRARED, STARS ID PICTORIS CIRCUMSTELLAR DISK; BETA-PICTORIS; STARS; IRAS; MATTER; GRAINS; CLOUD AB The 10-mu-m spectrum of the K5V star SAO 179815 (= HD 98800) is presented, and conclusively demonstrates the presence of small silicate dust grains (probably in a disc) around this star. The 9.7-mu-m silicate dust feature is unusually broad and shallow in this system. This, together with the slow fall-off of flux at longer wavelengths, constrains the size and density distributions of dust grains in models of the disc. We find that there must be a significant population of small grains (radii at least as small as 0.01-mu-m), as well as a population of large grains (radii at least as large as 100-mu-m) in order to explain all the observed properties of the disc. C1 UNIV LONDON UNIV COLL,DEPT PHYS & ASTRON,LONDON WC1E 6BT,ENGLAND. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP SKINNER, CJ (reprint author), UNIV MANCHESTER,NUFFIELD RADIO ASTRON LABS,JODRELL BANK,MACCLESFIELD SK11 9DL,CHESHIRE,ENGLAND. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 22 TC 20 Z9 20 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD APR 1 PY 1992 VL 255 IS 3 BP P31 EP P36 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HL902 UT WOS:A1992HL90200023 ER PT J AU SUD, YC CHAO, WC WALKER, GK AF SUD, YC CHAO, WC WALKER, GK TI ROLE OF A CUMULUS PARAMETERIZATION SCHEME IN SIMULATING ATMOSPHERIC CIRCULATION AND RAINFALL IN THE 9-LAYER GODDARD LABORATORY FOR ATMOSPHERES GENERAL-CIRCULATION MODEL SO MONTHLY WEATHER REVIEW LA English DT Article ID CONVECTION; RADIATION; ENSEMBLE AB A coarse (4-degrees x 5-degrees x 9-sigma level) version of the Goddard Laboratory for Atmospheres (GLA) General Circulation Model (GCM) was used to investigate the influence of a cumulus convection scheme on the simulated atmospheric circulation and hydrologic cycle. Two sets of integrations, each containing an ensemble of three summer (June, July, and August) simulations, were produced. The first set, containing control cases, included a state-of-the-art cumulus parameterization scheme in the GCM; whereas the second set, containing experiment cases, used the same GCM but without the cumulus parameterization. All simulations started from initial conditions that were taken from analysis of observations for three consecutive initial times that were only 12 h apart, beginning with 0000 UTC 19 May 1988. The climatological boundary conditions-sea surface temperature, snow, ice, and vegetation cover-were kept exactly the same for all the integrations. The ensemble sets of control and experiment simulations are compared and differentially analyzed to determine the influence of a cumulus convection scheme on the simulated circulation and hydrologic cycle. The results show that cumulus parameterization has a very significant influence on the simulated circulation and precipitation. The influence is conspicuous in tropical regions, interior of continents in the Northern Hemisphere, and some oceanic regions. The upper-level condensation heating over the intertropical convergence zone (ITCZ) is much smaller for the experiment simulations as compared to the control simulations; correspondingly, the Hadley and Walker cells for the control simulations are also weaker and are accompanied by a weaker Ferrel cell in the Southern Hemisphere. The rainfall under the rising branch of the southern Ferrel cell (at about 50-degrees-S) does not increase very much because boundary-layer convergence poleward reduces the local evaporation. Overall, the difference fields show that experiment simulations (without cumulus convection) produce a cooler and less energetic atmosphere. The vertical profile of the zonally averaged diabatic heating also shows large differences in the tropics that are physically consistent with accompanying differences in circulation. Despite producing a warmer and wetter planetary boundary layer (PBL) in the tropics (20-degrees-S-20-degrees-N), the control simulations also produce a warmer but drier 400-mb level. The moisture transport convergence fields show that while only the stationary circulation is affected significantly in the PBL, both the stationary and eddy moisture transports are altered significantly in the atmosphere above the PBL. These differences not only reaffirm the important role of cumulus convection in maintaining the global circulation, but also show the way in which the presence or absence of a cumulus parameterization scheme can affect the circulation and rainfall climatology of a GCM. RP SUD, YC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 911,GREENBELT,MD 20771, USA. NR 23 TC 14 Z9 14 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 APR PY 1992 VL 120 IS 4 BP 594 EP 611 DI 10.1175/1520-0493(1992)120<0594:ROACPS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HK879 UT WOS:A1992HK87900007 ER PT J AU EGALON, CO ROGOWSKI, RS AF EGALON, CO ROGOWSKI, RS TI EFFICIENCY OF CORE LIGHT INJECTION FROM SOURCES IN THE CLADDING - BULK DISTRIBUTION SO OPTICAL ENGINEERING LA English DT Article DE CIRCULAR OPTICAL FIBERS; OPTICAL FLUOROSENSORS; ELECTROMAGNETIC THEORY; BULK DISTRIBUTION OF SOURCES; EVANESCENT WAVE; OPTICAL FIBER CHEMICAL SENSORS; STEP-INDEX PROFILE FIBERS ID FLUORESCENCE; EXCITATION AB The behavior of the power efficiency P(eff) of an optical fiber with a bulk distribution of source in its cladding is analyzed. The expressions derived make use of the exact field solution of a cylindrical fiber, whereas previous work has made use of the weakly guiding approximation. Although more complicated and harder to interpret, the formulas presented allow the analysis of the power injection efficiency of fibers with arbitrary differences in indices of refraction. The results obtained are relevant to the design of more efficient optical fiber fluorosensors. The conclusions follow. Previous results using the weakly guiding approximation were confirmed. However, we have found that P(eff) does not always increase with the V number; it does, however, increase with the difference in the indices of refraction, n(core) - n(clad), and the wavelength lambda. It also decreases with the fiber core radius a. Finally, a new independent variable, a/lambda, was found. RP EGALON, CO (reprint author), NASA,LANGLEY RES CTR,NON DESTRUCT EVALUAT SCI BRANCH,MAIL STOP 231,HAMPTON,VA 23665, USA. NR 14 TC 9 Z9 9 U1 1 U2 1 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 APR PY 1992 VL 31 IS 4 BP 846 EP 851 DI 10.1117/12.56111 PG 6 WC Optics SC Optics GA HQ324 UT WOS:A1992HQ32400028 ER PT J AU LEE, AY AF LEE, AY TI SOLVING CONSTRAINED MINIMUM-TIME ROBOT PROBLEMS USING THE SEQUENTIAL GRADIENT RESTORATION ALGORITHM SO OPTIMAL CONTROL APPLICATIONS & METHODS LA English DT Article DE MINIMUM-TIME CONTROL; CONSTRAINED MANIPULATOR; BOUNDED POWER AB In this paper three constrained minimum-time control problems of a two-link manipulator are solved using the sequential gradient and restoration algorithm (SGRA). In addition to the hard bounds on the control torques commonly considered in the literature, we also consider cases with bounded output power and with a constrained shoulder arm. The inequality constraints considered are reduced via Valentine-type transformations to non-differential path equality constraints. The SGRA is then used to solve these transformed problems with equality constraints. The results obtained indicate that at least one of the two controls is at its limits at any instant in time. The remaining control then adjusts itself so that none of the system constraints is violated. Hence the minimum-time control is either a pure bang-bang control or a combined bang-bang/singular control. RP LEE, AY (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 7 Z9 7 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0143-2087 J9 OPTIM CONTR APPL MET JI Optim. Control Appl. Methods PD APR-JUN PY 1992 VL 13 IS 2 BP 145 EP 154 DI 10.1002/oca.4660130205 PG 10 WC Automation & Control Systems; Operations Research & Management Science; Mathematics, Applied SC Automation & Control Systems; Operations Research & Management Science; Mathematics GA KG041 UT WOS:A1992KG04100004 ER PT J AU WALLACE, TA CLARK, RK WIEDEMANN, KE SANKARAN, SN AF WALLACE, TA CLARK, RK WIEDEMANN, KE SANKARAN, SN TI OXIDATION CHARACTERISTICS OF TI-25AL-10NB-3V-1MO SO OXIDATION OF METALS LA English DT Article DE OXIDATION; TITANIUM ALUMINIDE; OXIDATION KINETICS; OXIDATION PRODUCTS AB Static oxidation kinetics of Ti-25Al-10Nb-3V-1Mo (atomic percent) were investigated in air over the temperature range of 650-1000-degrees-C using thermogravimetric analysis. The oxidation kinetics were complex at all exposure temperatures and displayed up to two distinct stages of parabolic oxidation. Breakaway oxidation occurred after long exposure times at high temperatures. Oxidation products were determined using x-ray diffraction techniques, electron microprobe analysis, and energy dispersive x-ray analysis. Oxide scale morphology was examined using scanning electron microscopy of the surfaces and cross-sections of oxidation specimens. The oxides during the parabolic stages were compact and multilayered, consisting primarily of TiO2 doped with Nb, a top layer of Al2O3 and a thin bottom layer of TiN. The transition between the first and second parabolic stage is linked to the formation of a TiAl layer at the oxide-metal interface. Porosity also formed in the TiO2 layer during the second stage, causing degradation of the oxide and breakaway oxidation. C1 ANALYT SERV & MAT INC,HAMPTON,VA 23666. RP WALLACE, TA (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 194,HAMPTON,VA 23665, USA. NR 11 TC 34 Z9 35 U1 2 U2 5 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0030-770X J9 OXID MET JI Oxid. Met. PD APR PY 1992 VL 37 IS 3-4 BP 111 EP 124 DI 10.1007/BF00665185 PG 14 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA HU972 UT WOS:A1992HU97200001 ER PT J AU NG, LL ERLEBACHER, G AF NG, LL ERLEBACHER, G TI SECONDARY INSTABILITIES IN COMPRESSIBLE BOUNDARY-LAYERS SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article AB The secondary instability mechanisms in a two-dimensional (2-D) compressible boundary layer over a flat plate have been examined for a range of Mach numbers up to 4.5. For subsonic and low supersonic flows, fundamental resonance dominates when the amplitude of the (2-D) primary disturbance is high, while subharmonic resonance prevails in an environment with a low primary disturbance. At a high supersonic Mach number of 4.5, the secondary instability of the second-mode primary is stronger than that of the first-mode primary. Further, the subharmonic and the combination resonance modes, which are slightly detuned from the subharmonic, are the dominant instabilities. The influence of the propagation direction of the primary disturbance on secondary instabilities is investigated at Mach 1.6. Whereas the fundamental and the subharmonic disturbances propagate synchronously with a 2-D primary wave, this is not true for an oblique primary. A subset of the secondary instability results is verified against direct numerical simulations. Some comparisons between spatial and temporal secondary instabilities have been made at Mach 1.6. C1 ANALYT SERV & MAT INC,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23665. RP NG, LL (reprint author), NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,MS-156,HAMPTON,VA 23665, USA. NR 19 TC 30 Z9 30 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 APR PY 1992 VL 4 IS 4 BP 710 EP 726 DI 10.1063/1.858290 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HK565 UT WOS:A1992HK56500011 ER PT J AU ELHADY, NM AF ELHADY, NM TI SECONDARY INSTABILITY OF HIGH-SPEED FLOWS AND THE INFLUENCE OF WALL COOLING AND SUCTION SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Article ID BOUNDARY-LAYER STABILITY AB The periodic streamwise modulation of the supersonic and hypersonic boundary layers by a two-dimensional first-mode or second-mode wave makes the resulting base flow susceptible to a broadband spanwise-periodic three-dimensional type of instability. The principal parametric resonance of this instability (subharmonic) has been analyzed using Floquet theory. The effect of Mach number and the effectiveness of wall cooling or wall suction in controlling the onset, the growth rate, and the vortical structure of the subharmonic secondary instability are assessed for both a first-mode and a second-mode primary wave. Results indicate that the secondary subharmonic instability of an insulated wall boundary layer is weakened as Mach number increases. Cooling of the wall destabilizes the secondary subharmonic of a second-mode primary wave, but stabilizes it when the primary wave is a first mode. Suction stabilizes the secondary subharmonic at all Mach numbers. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP ELHADY, NM (reprint author), ANALYT SERV & MAT INC,HAMPTON,VA 23666, USA. NR 20 TC 9 Z9 9 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD APR PY 1992 VL 4 IS 4 BP 727 EP 743 DI 10.1063/1.858291 PG 17 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HK565 UT WOS:A1992HK56500012 ER PT J AU BILITZA, D AF BILITZA, D TI SOLAR TERRESTRIAL MODELS AND APPLICATION SOFTWARE SO PLANETARY AND SPACE SCIENCE LA English DT Review ID INCOHERENT-SCATTER OBSERVATIONS; GEOMAGNETIC REFERENCE FIELD; MAGNETOSPHERIC MAGNETIC-FIELD; LATITUDE IONOSPHERIC MODEL; CONVECTION ELECTRIC-FIELD; EQUAL-TO 75-DEGREES; EMPIRICAL-MODELS; THERMOSPHERIC MODEL; AURORAL CONVECTION; FOF2 COEFFICIENTS AB Models describing the different regions of the solar terrestrial environment are of great importance for a wide spectrum of scientific, engineering and educational applications. In an effort to assist model users, more than 80 models and application programs are described in this paper. For each entry the information provided includes model author(s), availability, brief description, and references. These models describe parameters in Earth's ionosphere, atmosphere, and magnetosphere, in the solar wind, and in the atmosphere and ionosphere of planet Venus. Almost all of the listed entries are empirical models i.e. models based primarily on measurements, rather than theoretically obtained values. All models use some type of solar-terrestrial index to describe parameter variations with solar cycle and magnetic activity. The definition and the availability of these indices is described in a separate chapter. Finally solar-terrestrial coordinate systems are explained and software for coordinate conversion between different systems is listed. RP BILITZA, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,CODE 9339-STX,GREENBELT,MD 20771, USA. NR 217 TC 31 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 APR PY 1992 VL 40 IS 4 BP 541 EP 579 DI 10.1016/0032-0633(92)90173-L PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HR354 UT WOS:A1992HR35400013 ER PT J AU BAKER, DN FAIRFIELD, DH SLAVIN, JA RICHARDSON, IG OWEN, CJ CRAVEN, JD FRANK, LA ELPHIC, RC SINGER, HJ ZWICKL, RD AF BAKER, DN FAIRFIELD, DH SLAVIN, JA RICHARDSON, IG OWEN, CJ CRAVEN, JD FRANK, LA ELPHIC, RC SINGER, HJ ZWICKL, RD TI THE SUBSTORM EVENT OF 28 JANUARY 1983 - A DETAILED GLOBAL STUDY SO PLANETARY AND SPACE SCIENCE LA English DT Article C1 UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99701. UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87549. PHG,GEOPHYS LAB,BEDFORD,MA 01731. SPACE ENVIRONM LAB,BOULDER,CO 80302. RP BAKER, DN (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Owen, Christopher/C-2999-2008; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Slavin, James/0000-0002-9206-724X NR 2 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 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 1992 VL 40 IS 4 BP 589 EP 590 DI 10.1016/0032-0633(92)90273-Q PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HR354 UT WOS:A1992HR35400015 ER PT J AU PRATT, LR POHORILLE, A AF PRATT, LR POHORILLE, A TI THEORY OF HYDROPHOBICITY - TRANSIENT CAVITIES IN MOLECULAR LIQUIDS SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE SOLUBILITIES; SCALED PARTICLE MODEL; CAVITY SIZE DISTRIBUTIONS; CAVITY FORMATION WORK; SURFACE TENSION ID NONPOLAR SOLUTES; VAPOR INTERFACE; MONTE-CARLO; WATER; DYNAMICS; EQUATION AB Observation of the size distribution of transient cavities in computer simulations of water, n-hexane, and n-dodecane under benchtop conditions shows that the sizes of cavities are more sharply defined in liquid water but the most-probable-size cavities are about the same size in each of these liquids. The calculated solvent atomic density in contract with these cavities shows that water applies more force per unit area of cavity surface than do the hydrocarbon liquids. This contact density, or "squeezing" force, reaches a maximum near cavity diameters of 2.4 angstrom. The results for liquid water are compared to the predictions of simple theories and, in addition, to results for a reference simple liquid. The numerical data for water at a range of temperatures are analyzed to extract a surface free energy contribution to the work of formation of atomic-size cavities. Comparison with the liquid-vapor interfacial tensions of the model liquids studied here indicates that the surface free energies extracted for atomic-size cavities cannot be accurately identified with the macroscopic surface tensions of the systems. C1 UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP PRATT, LR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, LOS ALAMOS, NM 87545 USA. RI Pratt, Lawrence/H-7955-2012 OI Pratt, Lawrence/0000-0003-2351-7451 FU NCI NIH HHS [NCA-2 315] NR 36 TC 176 Z9 176 U1 2 U2 23 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 1 PY 1992 VL 89 IS 7 BP 2995 EP 2999 DI 10.1073/pnas.89.7.2995 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HL816 UT WOS:A1992HL81600100 PM 11537863 ER PT J AU HEINTZ, R JOYCE, J AF HEINTZ, R JOYCE, J TI SMALL VERTICAL RACEWAYS FOR REARING JUVENILE SALMON SO PROGRESSIVE FISH-CULTURIST LA English DT Note AB We describe a micro-vertical raceway, a small floating container, for rearing small populations of fish. The container is a 170.6-L polyethylene drum fitted to a controlled water supply. An array of these containers was used to rear juvenile salmon simultaneously in 60 groups (200 fish each) to 6.0-g size. We compared growth rates of juvenile chinook salmon (Oncorhynchus tshawytscha) reared in these containers with those reared in large (70.8-m3) vertical raceways and conclude that micro-vertical raceways do not adversely affect fish growth. RP HEINTZ, R (reprint author), ALASKA FISHERIES SCI CTR,NATL MARINE FISHERIES SERV,AUKE BAY LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 5 TC 7 Z9 7 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0033-0779 J9 PROG FISH CULT JI Progress. Fish-Cult. PD APR PY 1992 VL 54 IS 2 BP 105 EP 108 DI 10.1577/1548-8640(1992)054<0105:SVRFRJ>2.3.CO;2 PG 4 WC Fisheries SC Fisheries GA JD752 UT WOS:A1992JD75200008 ER PT J AU ARNAUD, KA ZHELEZNYAKOV, VV TRIMBLE, V AF ARNAUD, KA ZHELEZNYAKOV, VV TRIMBLE, V TI CORONAL X-RAYS FROM SINGLE, MAGNETIC WHITE-DWARFS - A SEARCH AND PROBABLE DETECTION SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID RADIATION; PLASMA AB We have searched for X-ray emission from a sample of five nearby (6-20 pc), strongly magnetic (10-200 MG), relatively cool (6000-14000 K), single white dwarfs, two of which may possess coronae. We detect one star (GR 290) at better than 99% confidence and give upper limits from Einstein Observatory IPC data for four others. The detected luminosities and limits are in the range 1.4-12.5 X 10(27) ergs s-1. C1 UNIV MARYLAND,ASTRON PROGRAM,COLLEGE PK,MD 20742. ACAD SCI USSR,INST APPL PHYS,GORKI 603600,USSR. UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. RP ARNAUD, KA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 666,GREENBELT,MD 20771, USA. NR 22 TC 8 Z9 8 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 APR PY 1992 VL 104 IS 674 BP 239 EP 241 DI 10.1086/132983 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HQ717 UT WOS:A1992HQ71700001 ER PT J AU TOWNSEND, LW CUCINOTTA, FA SHINN, JL WILSON, JW AF TOWNSEND, LW CUCINOTTA, FA SHINN, JL WILSON, JW TI RISK ANALYSES FOR THE SOLAR PARTICLE EVENTS OF AUGUST THROUGH DECEMBER 1989 SO RADIATION RESEARCH LA English DT Article RP TOWNSEND, LW (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,MAIL STOP 493,HAMPTON,VA 23665, USA. NR 18 TC 10 Z9 10 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD APR PY 1992 VL 130 IS 1 BP 1 EP 6 DI 10.2307/3578472 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA HM582 UT WOS:A1992HM58200001 PM 1561307 ER PT J AU HUGHJONES, M BARRE, N NELSON, G WEHNES, K WARNER, J GARVIN, J GARRIS, G AF HUGHJONES, M BARRE, N NELSON, G WEHNES, K WARNER, J GARVIN, J GARRIS, G TI LANDSAT-TM IDENTIFICATION OF AMBLYOMMA-VARIEGATUM (ACARI, IXODIDAE) HABITATS IN GUADELOUPE SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID VEGETATION; IXODOIDEA; ECOLOGY; VECTORS AB The objective of this study in 1986-1987 was to determine whether it was possible to remotely identify the specific habitat or habitats of the African bont tick, Amblyomma variegatum, using Landsat-TM imagery data. An unsupervised classification of the April 1986 image was carried out using LAS KMEANS and SPCSRT. The predictability of the landcover classes was determined by visiting random preselected sites within wetlands, woodlands, canefields, and grazing. On a second visit adult ticks were counted in over 103 herds and the habitats recorded. Descriminant analysis indicated that there were a limited number of tick habitats. The tick counts for the herds within these habitats indicate that each habitat probably has a characteristic tick density. The visible farms in Grande Terre, representing four habitats, were then compared with the landcover classes found in a 5 x 5 pixel array at each farm site in the classified image. The habitats could be separated using principal component analysis. Divisive clustering analysis was applied to the band values and derived indices for a similar sized array for each farm site visible in the original unclassified image of Guadeloupe. This analysis clustered the sites by large and small variance of band values, and by vegetation and moisture indices. Herds in heterogeneous sites with large variances had more ticks than those in homogeneous or low variance sites. Within the heterogeneous sites, those with high vegetation and moisture indices had more ticks than those with low values. C1 CTR RECH ANTILLES & GUYANE,INST ELEVAGE & MED VET PAYS TROP MISSION,TICK RES UNIT,POINTE A PITRE,GUADELOUPE. USA,MED RES INST INFECT DIS,DIV DATA PROC,FREDERICK,MD 21701. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. USDA ARS,US LIVESTOCK INSECT LAB,KERRVILLE,TX. RP HUGHJONES, M (reprint author), LOUISIANA STATE UNIV,SCH VET MED,DEPT EPIDEMIOL & COMMUNITY HLTH,BATON ROUGE,LA 70803, USA. NR 23 TC 25 Z9 25 U1 0 U2 7 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 APR PY 1992 VL 40 IS 1 BP 43 EP 55 DI 10.1016/0034-4257(92)90125-4 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA HK758 UT WOS:A1992HK75800004 ER PT J AU BOWLES, KJ AF BOWLES, KJ TI EFFECT OF FIBER REINFORCEMENTS ON THERMOOXIDATIVE STABILITY AND MECHANICAL-PROPERTIES OF POLYMER MATRIX COMPOSITES SO SAMPE QUARTERLY-SOCIETY FOR THE ADVANCEMENT OF MATERIAL AND PROCESS ENGINEERING LA English DT Article ID CARBON-FIBERS AB This study shows the influence of the reinforcement fibers on the oxidative degradation of various polymer matrix composites. The polyimide PMR-15 was the matrix material that was used in these studies. The control composite was reinforced with Celion 6000 graphite fibers (BASF). T-40R (AMOCO) graphite fibers along with some very stable ceramic fibers, were selected as reinforcing fibers because of their high thermal stability. The ceramic fibers were Nicalon (Dow Corning silicon carbide) and Nextel 312 (3M alumina-silica-boron oxide). The initial mechanical properties of the two graphite fiber composites were significantly different, probably due to variations in the interfacial bonding between the fibers and the polyimide matrix. The Celion 6000 bond appears to be stronger than the T-40R bond. Three oxidation mechanisms were observed. One involved the preferential oxidation of the Celion 6000 fiber ends at cut surfaces, leaving a surface of matrix material with holes where the fiber ends were originally situated; the second, preferential oxidation of the composite matrix; and the third, interfacial degradation by oxidation. RP BOWLES, KJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 20 TC 4 Z9 6 U1 1 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0036-0821 J9 SAMPE QUART PD APR PY 1992 VL 23 IS 3 BP 2 EP 12 PG 11 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA HM800 UT WOS:A1992HM80000001 ER PT J AU BINIENDA, WK ROBERTS, GD PAPADOPOULOS, DS AF BINIENDA, WK ROBERTS, GD PAPADOPOULOS, DS TI EFFECT OF CONTACT STRESSES IN 4-POINT BEND TESTING OF GRAPHITE EPOXY AND GRAPHITE PMR-15 COMPOSITE BEAMS SO SAMPE QUARTERLY-SOCIETY FOR THE ADVANCEMENT OF MATERIAL AND PROCESS ENGINEERING LA English DT Article AB In this paper, the results of in-plane four-point bend experiments on unidirectionally reinforced composite beams are presented for graphite/epoxy (T300/934) and graphite/polyimide (G30-500/PMR-15) composites. The maximum load and the location of cracks formed during failure were measured for testpieces with fibers oriented at various angles to the beam axis. Since most of the beams failed near one or more of the load points, the strength of the beams was evaluated in terms of a proposed model for the local stress distribution. In this model, an exact solution to the problem of a localized contact force acting on a unidirectionally reinforced half plane is used to describe the local stress field. The stress singularity at the load point is treated in a manner similar to the stress singularity at a crack tip in fracture mechanics problems. Using this approach, the effect of fiber angle and elastic material properties on the strength of the beam is described in terms of a load intensity factor. For fiber angles less than 45-degrees from the beam axis, a single crack is initiated near one of the load points at a critical value of the load intensity factor. The critical load intensity factor decreases with increasing fiber angle. For larger fiber angles, multiple cracks occur at locations both near and away from the load points, and the load intensity factor at failure increases sharply with increasing fiber angle. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP BINIENDA, WK (reprint author), UNIV AKRON,DEPT CIVIL ENGN,AKRON,OH 44325, USA. NR 11 TC 1 Z9 1 U1 0 U2 4 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0036-0821 J9 SAMPE QUART PD APR PY 1992 VL 23 IS 3 BP 20 EP 28 PG 9 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA HM800 UT WOS:A1992HM80000003 ER PT J AU TOMPKINS, SS FUNK, JG AF TOMPKINS, SS FUNK, JG TI SENSITIVITY OF THE COEFFICIENT OF THERMAL-EXPANSION OF SELECTED GRAPHITE REINFORCED COMPOSITE LAMINATES TO LAMINA THERMOELASTIC PROPERTIES SO SAMPE QUARTERLY-SOCIETY FOR THE ADVANCEMENT OF MATERIAL AND PROCESS ENGINEERING LA English DT Article AB An analytical study of the sensitivity of the laminate coefficient of thermal expansion, CTE, to changes in lamina elastic properties has been made. High modulus graphite/epoxy (P75/934, P100/934, P120/934), graphite/aluminum (P100/Al), and graphite/glass (HMS/Gl) composite materials were considered in quasi-isotropic, low thermal stress, and "near-zero" thermal expansion laminate configurations. The effects of a positive or negative 10% change in lamina properties on laminate CTE is strongly dependent upon both the composite material and the laminate configuration. A 10% change in all of the lamina properties had very little effect on the laminate CTE of the HMS/Gl composite laminates investigated. The sensitivity and direction of change in the laminate CTE of Gr/934 depended very strongly on the fiber properties. A 10% change in the lamina transverse CTE resulted in changes as large as 0.216 ppm/degrees-C in the laminate CTE of a quasi-isotropic Gr/934 laminate. No significant difference was observed in the sensitivity of the laminate CTE of the P100/934 and P120/934 composite materials due to changes in lamina properties. Large changes in laminate CTE can result from measured temperature and radiation effects on lamina properties. RP TOMPKINS, SS (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 16 TC 3 Z9 3 U1 1 U2 4 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0036-0821 J9 SAMPE QUART PD APR PY 1992 VL 23 IS 3 BP 55 EP 61 PG 7 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA HM800 UT WOS:A1992HM80000009 ER PT J AU HOYT, DV SCHATTEN, KH AF HOYT, DV SCHATTEN, KH TI A NEW LOOK AT WOLF SUNSPOT NUMBERS IN THE LATE 1700S SO SOLAR PHYSICS LA English DT Article AB Long-term homogeneous observations of solar activity or many solar cycles are essential for investigating many problems in solar physics and climatology. The one key parameter used in most long-term studies is the Wolf sunspot number, which is susceptible to observer bias, particularly because it is highly sensitive to the observer's ability to see the smallest sunspots. In this paper we show how the Wolf sunspot number can be derived from the number of sunspot groups alone. We utilize this approach to obtain a 'Group Wolf number'. This technique has advantages over the classical method of determining the Wolf number because corrections for observer differences are reduced and long-term self-consistent time series can be developed. The level of activity can be calculated to an accuracy of +/- 5% using this method. Applying the technique to Christian Horrebow's observations of solar cycles 1, 2, and 3 (1761-1777), we find that the standard Wolf numbers are nearly homogeneous with sunspot numbers measured from 1875 to 1976 except the peak of solar cycle 2 is too low by 30%. This result suggests that further analyses of early sunspot observations could lead to significant improvements in the uniformity of the measurements of solar activity. Such improvements could have important impacts upon our understanding of long-term variations in solar activity, such as the Gleissberg cycle, or secular variations in the Earth's climate. C1 NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RP HOYT, DV (reprint author), RES & DATA SYST CORP, GREENBELT, MD 20770 USA. NR 15 TC 15 Z9 15 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 EI 1573-093X J9 SOL PHYS JI Sol. Phys. PD APR PY 1992 VL 138 IS 2 BP 387 EP 397 DI 10.1007/BF00151922 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HX292 UT WOS:A1992HX29200011 ER PT J AU KOHRS, RH AF KOHRS, RH TI SPACE STATION PROGRAM STATUS SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article; Proceedings Paper CT 7TH COLUMBUS SYMP ON SPACE STATION UTILIZATION CY JUL 01-06, 1991 CL ANACAPRI, ITALY AB The international Space Station Freedom program is moving progressively toward the goal of establishing a permanent outpost in low Earth orbit. Beginning with the attainment of a Man-Tended Capability in 1997, followed by Permanently Manned Capability by the year 2000, unprecedented state of the art facilities will be available to the user communities of each of the international partners for the conduct of life science and microgravity materials research. RP KOHRS, RH (reprint author), NASA,SPACE STN FREEDOM,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD APR PY 1992 VL 12 IS 2 BP 131 EP 132 PG 2 WC Engineering, Aerospace SC Engineering GA HJ539 UT WOS:A1992HJ53900009 ER PT J AU GOLBEN, J VLASSE, M AF GOLBEN, J VLASSE, M TI STUDY OF BULK AND SINGLE-CRYSTAL YBA2-XSRXCU3O7-DELTA SUPERCONDUCTING MATERIALS SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article AB A detailed study of the substitution of Sr for Ba in the system YBa2-xSrxCu3O7-delta has been carried out, for both bulk and single-crystal material. Successful substitution, in bulk samples, of up to 80% (x = 1.6) was accomplished. This substitution is seen to have an adverse progressive effect on the value of T(c). All bulk Sr-substituted compounds were superconducting with values of T(c) of at least 73 K. The 100% Sr-substituted sample YSr2Cu3O7-delta has been observed, but only in very small amounts. Single crystals of Y(Ba, Sr)2CU3O7-delta with Sr/Ba substitution of up to 30% (x = 0.6) have also been synthesized and characterized by XRD and SEM. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP GOLBEN, J (reprint author), SCI & TECHNOL CORP,HUNTSVILLE,AL, USA. NR 5 TC 16 Z9 16 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD APR PY 1992 VL 5 IS 4 BP 231 EP 235 DI 10.1088/0953-2048/5/4/006 PG 5 WC Physics, Applied; Physics, Condensed Matter SC Physics GA HT775 UT WOS:A1992HT77500006 ER PT J AU VLASSE, M GOLBEN, J MITCHELL, T AF VLASSE, M GOLBEN, J MITCHELL, T TI PROCESS OPTIMIZATION FOR THE PB-SUBSTITUTED AND SB-SUBSTITUTED BI-BASED 2/2/2/3 BULK CERAMIC SUPERCONDUCTORS SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article ID ZERO RESISTANCE; SYSTEM; TRANSITION AB The synthesis and superconducting properties of Pb- and Sb-substituted Bi-2:2:2:3 materials have been investigated. The preparation conditions for the formation of the pure 2:2:2:3 phase have been optimized. Actual Sb-substitution into the Bi-system 2:2:2:3 phase was successful as indicated by the XRD study. The transport measurements revealed no significant enhancement of the critical temperature such as was reported previously for the Sb-substituted phase. However, an enhanced melt-sintering orientation effect was observed in samples containing unreacted Sb2O3. C1 SCI & TECHNOL CORP,HUNTSVILLE,AL. RP VLASSE, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 11 TC 12 Z9 12 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD APR PY 1992 VL 5 IS 4 BP 236 EP 239 DI 10.1088/0953-2048/5/4/007 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA HT775 UT WOS:A1992HT77500007 ER PT J AU PARTRIDGE, H FAEGRI, K AF PARTRIDGE, H FAEGRI, K TI HIGH-QUALITY GAUSSIAN-BASIS SETS FOR 4TH-ROW ATOMS SO THEORETICA CHIMICA ACTA LA English DT Article DE GAUSSIAN BASIS SETS; HIGH-QUALITY; 4TH-ROW ATOMS; TRIPLE-ZETA VALENCE DISTRIBUTION ID TRANSITION-METAL ATOMS; GTO BASIS-SETS; HARTREE-FOCK; WAVE-FUNCTIONS; 2ND-ROW ATOMS; ELEMENTS; ORBITALS; 1ST-ROW; SIZE; 1ST AB Energy-optimized Gaussian basis sets of triple-zeta quality for the atoms Rb-Xe have been derived. Two series of basis sets are developed; (24s 16p 10d) and (26s 16p 10d) sets which we expand to 13 d and 19 p functions as the 4d and 5p shells become occupied. For the atoms lighter than Cd, the (24s 16p 10d) sets with triple-zeta valence distributions are higher in energy than the corresponding double-zeta distribution. To ensure a triple-zeta distribution and a global energy minimum the (26s ]6p 10d) sets were derived. Total atomic energies from the largest basis sets are between 198 and 284-mu-E(H) above the numerical Hartree-Fock energies. C1 UNIV OSLO,DEPT CHEM,POB 1033 BLINDERN,N-0315 OSLO 3,NORWAY. RP PARTRIDGE, H (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 21 TC 41 Z9 41 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD APR PY 1992 VL 82 IS 3-4 BP 207 EP 212 DI 10.1007/BF01113252 PG 6 WC Chemistry, Physical SC Chemistry GA HR397 UT WOS:A1992HR39700003 ER PT J AU LIM, SG BREWE, DE AF LIM, SG BREWE, DE TI A SYSTEM-APPROACH TO THE ELASTOHYDRODYNAMIC LUBRICATION POINT-CONTACT PROBLEM SO TRIBOLOGY TRANSACTIONS LA English DT Article AB The classical EHL point contact problem is solved using a new "system-approach," similar to that introduced by Houpert and Hamrock for the line-contact problem. Introducing a body-fitted coordinate system, the troublesome free-boundary is transformed to the fixed domain. The Newton-Raphson method can then be used to determine the pressure distribution and the cavitation boundary subject to the Reynolds boundary condition. This method provides an efficient and rigorous way of solving the EHL point contact problem with the aid of a supercomputer and a promising method to deal with the transient EHL point contact problem. A typical pressure distribution and film thickness profile are presented and the minimum film thicknesses are compared with the solution of Hamrock and Dowson. The details of the cavitation boundaries for various operating parameters are discussed. RP LIM, SG (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 13 TC 8 Z9 8 U1 0 U2 3 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD APR PY 1992 VL 35 IS 2 BP 367 EP 373 DI 10.1080/10402009208982130 PG 7 WC Engineering, Mechanical SC Engineering GA HP626 UT WOS:A1992HP62600020 ER PT J AU MURPHY, OJ HITCHENS, GD KABA, L VEROSTKO, CE AF MURPHY, OJ HITCHENS, GD KABA, L VEROSTKO, CE TI DIRECT ELECTROCHEMICAL OXIDATION OF ORGANICS FOR WASTE-WATER TREATMENT SO WATER RESEARCH LA English DT Article DE ELECTROCHEMICAL OXIDATION; ORGANICS; WATER TREATMENT ID OZONE; EVOLUTION AB A single cell electrochemical reactor that utilizes a proton exchange membrane (PEM) as a solid electrolyte was investigated for the treatment of waters with low or negligible electrolyte content. The electrochemical reactor concept, test system design, the role of the proton exchange membrane and the principle of organic impurity oxidation at PEM/electrocatalyst interfacial reaction zones are outlined. Test data and kinetic analysis are presented. The feasibility and application for water reclamation processes in controlled ecological environments (e.g. lunar/Mars habitats) are discussed. The approach has potential as a terrestrial water pollution control method. C1 TEXAS A&M UNIV SYST,CTR ELECTROCHEM SYST & HYDROGEN RES,COLLEGE STN,TX 77843. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP MURPHY, OJ (reprint author), LYNNTECH INC,111 E 27TH ST,SUITE 204,BYRAN,TX 77803, USA. NR 30 TC 97 Z9 102 U1 4 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0043-1354 J9 WATER RES JI Water Res. PD APR PY 1992 VL 26 IS 4 BP 443 EP 451 DI 10.1016/0043-1354(92)90044-5 PG 9 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA HM291 UT WOS:A1992HM29100006 ER PT J AU TORRES, MR MCCLURE, JC NUNES, AC GUREVITCH, AC AF TORRES, MR MCCLURE, JC NUNES, AC GUREVITCH, AC TI GAS CONTAMINATION EFFECTS IN VARIABLE POLARITY PLASMA-ARC WELDED ALUMINUM SO WELDING JOURNAL LA English DT Article DE GAS CONTAMINANTS; PLASMA ARC WELDING; ALUMINUM PLATE; VARIABLE POLARITY PAW; VPPAW; POROSITY; KEYHOLE; COVER PASS; OXIDE FILMS; SHIELDING GAS AB A series of variable polarity plasma arc welds were made on 0.25-in. (0.635-cm) thick 2219 aluminum sheet using carefully measured contaminant levels of oxygen, hydrogen, nitrogen and methane in both the arc and shielding gases. Porosity, asymmetric undercutting, incomplete fusion and fine extrusions at the edge of the weld were found to be associated with various levels of contamination. Many of the phenomena can be interpreted by noting that little or no true sputtering took place during the reverse polarity cycle, rather the surface tension of the weld pool was altered by even low fluxes of contaminant gases. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAT & PROC LAB,HUNTSVILLE,AL 35812. RP TORRES, MR (reprint author), UNIV TEXAS,DEPT MET & MAT ENGN,EL PASO,TX 79968, USA. NR 14 TC 3 Z9 3 U1 1 U2 1 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 SN 0043-2296 J9 WELD J JI Weld. J. PD APR PY 1992 VL 71 IS 4 BP S123 EP S131 PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA HL756 UT WOS:A1992HL75600014 ER PT J AU CHYU, WJ BENCZE, DP AF CHYU, WJ BENCZE, DP TI NAVIER-STOKES SIMULATION OF FLOW THROUGH A HIGHLY CONTOURED SUBSONIC DIFFUSER SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT 2ND WORLD CONGRESS OF COMPUTATIONAL MECHANICS CY AUG 27-31, 1990 CL INST COMPUTER APPLICATIONS, STUTTGART, GERMANY HO INST COMPUTER APPLICATIONS ID DIFFERENCE AB The flow through a highly offset subsonic diffuser with cross-sectional profiles that varied from rectangular at the duct entrance to circular at the engine face was numerically simulated. A multizonal approach combined with a two-grid topology was used to represent both the internal and external flow fields, and an implicit, approximately-factored, partially flux-split finite-difference algorithm was used to solve the three-dimensional thin-layer Navier-Stokes equations. The computed static pressures along the inlet wall and total pressures on the engine face were compared with experimental data. In addition, the overall flow field within the duct was examined in detail. Good agreement is shown between experiment and computations, with the limiting factor being the lack of a reliable turbulence model for internal flow problems. RP CHYU, WJ (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD MAR 30 PY 1992 VL 34 IS 2 BP 473 EP 483 DI 10.1002/nme.1620340207 PG 11 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA HH694 UT WOS:A1992HH69400006 ER PT J AU ALJUMAILY, GA EDLOU, SM AF ALJUMAILY, GA EDLOU, SM TI OPTICAL-PROPERTIES OF TANTALUM PENTOXIDE COATINGS DEPOSITED USING ION-BEAM PROCESSES SO THIN SOLID FILMS LA English DT Article ID THIN-FILMS; TA2O5; CONSTANTS AB Optical properties and environmental stability of tantalum pentoxide coatings have been examined. Coatings are deposited using thermal evaporation, ion-assisted deposition and reactive d.c. sputtering. Coatings deposited using ion beam processes are stable with much improved optical properties compared with conventionally evaporated coatings. C1 BARR ASSOCIATES INC,WESTFORD,MA 01886. RP ALJUMAILY, GA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 14 TC 22 Z9 23 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAR 30 PY 1992 VL 209 IS 2 BP 223 EP 229 DI 10.1016/0040-6090(92)90679-6 PG 7 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HR619 UT WOS:A1992HR61900016 ER PT J AU RICE, JE SCUSERIA, GE LEE, TJ TAYLOR, PR ALMLOF, J AF RICE, JE SCUSERIA, GE LEE, TJ TAYLOR, PR ALMLOF, J TI CONNECTED TRIPLE EXCITATIONS IN COUPLED-CLUSTER CALCULATIONS OF HYPERPOLARIZABILITIES - NEON SO CHEMICAL PHYSICS LETTERS LA English DT Article ID FULL CCSDT MODEL; ELECTRON CORRELATION; POLARIZABILITIES; HF AB We have calculated the second hyperpolarizability gamma of neon using the CCSD(T) method. The accuracy of the CCSD(T) approach has been established by explicit comparison with the single, double and triple excitation coupled-cluster (CCSDT) method using extended basis sets that are known to be adequate for the description of gamma. Our best estimate for gamma(0) of 110 +/- 3 au is in good agreement with other recent theoretical values and with Shelton's recent experimental estimate of 108 +/- 2 au. Comparison of the MP2 and CCSD(T) hyperpolarizability values indicates that MP2 gives a very good description of the electron correlation contribution to gamma(0). We have combined MP2 frequency-dependent corrections with the CCSD(T) gamma(0) value to yield gamma(-2-omega; omega, omega, 0) and gamma(k)(-omega; omega, 0, 0). C1 RICE UNIV,DEPT CHEM,HOUSTON,TX 77251. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. ELORET INST,PALO ALTO,CA 94303. UNIV MINNESOTA,DEPT CHEM,MINNEAPOLIS,MN 55455. UNIV MINNESOTA,INST SUPERCOMP,MINNEAPOLIS,MN 55455. RP RICE, JE (reprint author), IBM CORP,DIV RES,ALMADEN RES CTR,650 HARRY RD,SAN JOSE,CA 95120, USA. RI Scuseria, Gustavo/F-6508-2011; Rice, Julia/K-4928-2012; Lee, Timothy/K-2838-2012 OI Rice, Julia/0000-0001-5059-5127; NR 25 TC 37 Z9 37 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAR 27 PY 1992 VL 191 IS 1-2 BP 23 EP 28 DI 10.1016/0009-2614(92)85362-E PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HM768 UT WOS:A1992HM76800004 ER PT J AU SIMONS, RN LEE, RQ PERL, TD AF SIMONS, RN LEE, RQ PERL, TD TI NEW TECHNIQUES FOR EXCITING LINEARLY TAPERED SLOT ANTENNAS WITH COPLANAR WAVE-GUIDE SO ELECTRONICS LETTERS LA English DT Article DE WAVE-GUIDES; SLOT ANTENNAS; ANTENNA FEEDERS AB Two new techniques for exciting a linearly tapered slot antenna (LTSA) with coplanar waveguide (CPW) are introduced. In the first approach, an air bridge is used to couple power from a CPW to an LTSA. In the second approach, power is electromagnetically coupled from a finite CPW (FCPW) to an LTSA. Measured results at 18 GHz show excellent return loss and radiation patterns. RP SIMONS, RN (reprint author), NASA,LEWIS RES CTR,MAIL STOP 54-5,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 3 TC 10 Z9 10 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAR 26 PY 1992 VL 28 IS 7 BP 620 EP 621 DI 10.1049/el:19920391 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA HM880 UT WOS:A1992HM88000011 ER PT J AU FRIESEN, LJ JACKSON, AA ZOOK, HA KESSLER, DJ AF FRIESEN, LJ JACKSON, AA ZOOK, HA KESSLER, DJ TI ANALYSIS OF ORBITAL PERTURBATIONS ACTING ON OBJECTS IN ORBITS NEAR GEOSYNCHRONOUS EARTH ORBIT SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB Orbital evolution has been numerically simulated for objects started in geosynchronous Earth orbit (GEO) or in orbits near GEO, during a project to study potential orbital debris problems in this region. Perturbations simulated include nonspherical terms in the Earth's geopotential field, lunar and solar gravity, and solar radiation pressure. Objects simulated include large satellites, for which solar radiation pressure is insignificant, and small particles (a few microns in diameter), for which solar radiation pressure is an important force. Results for large satellites are largely in agreement with previous GEO studies that used classical perturbation techniques; orbital evolution studies were extended to possible storage orbits slightly above or below GEO. One notes that while the orbit planes of GEO satellites initially placed in equatorial orbits precess, so that those orbits reach inclinations of 14-degrees to 15-degrees to the equator, a ''stable plane'' exists inclined approximately 7.3-degrees to the equator. The orbit planes of GEO satellites placed in such a stable plane orbit experience very little precession, remaining always within 1.2-degrees of their initial orientation. Solar radiation pressure generates two major effects on small particles. One is an orbital eccentricity oscillation anticipated from previous research. The other is an oscillation in orbital inclination. This orbital inclination pattern is due to a precession of the small particle's orbital angular momentum vector about an axis offset from the Earth's polar axis. The magnitude of the precession axis offset angle depends on the particle's cross-sectional area to mass ratio. The rate for this precession differs greatly from the precession rate predicted in a previous study using perturbation techniques. This difference points up the inadequacy of those perturbation techniques for orbits with large eccentricities. For one sequence of runs with small particles, Poynting-Robertson drag was added to the simulation in order to slowly reduce the orbital semimajor axis and probe for possible orbital period resonances near the GEO distance. A significant resonance was found at the geosynchronous distance, where small grains are trapped into a 1:1 resonance with the Earth's daily rotation. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77256. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 21 TC 17 Z9 17 U1 2 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 25 PY 1992 VL 97 IS E3 BP 3845 EP 3863 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA KU047 UT WOS:A1992KU04700002 ER PT J AU GIBSON, EK AF GIBSON, EK TI VOLATILES IN INTERPLANETARY DUST PARTICLES - A REVIEW SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INTER-PLANETARY DUST; EXTRATERRESTRIAL ORIGIN; COMET HALLEY; CARBONACEOUS CHONDRITES; STRATOSPHERIC PARTICLES; METEORITES; COMPONENT; ISOTOPES; OXYGEN AB The paper presents a review of the volatiles found within interplanetary dust particles. These particles have been shown to represent primitive material from early in the solar system's formation and also may contain records of stellar processes. The organogenic elements (i.e., H, C, N, O, and S) are among the most abundant elements in our solar system, and their abundances, distributions, and isotopic compositions in early solar system materials permit workers to better understand the processes operating early in the evolutionary history of solar system materials. Interplanetary dust particles have a range of elemental compositions, but generally they have been shown to be similar to carbonaceous chondrites, the solar photosphere. Comet Halley's chondritic cores, and matrix materials of chondritic chondrites. Recovery and analysis of interplanetary dust particles have opened new opportunities for analysis of primitive materials, although interplanetary dust particles represent major challenges to the analyst because of their small size. C1 NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. NR 89 TC 15 Z9 15 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 25 PY 1992 VL 97 IS E3 BP 3865 EP 3875 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA KU047 UT WOS:A1992KU04700003 PM 11537855 ER PT J AU METCALF, VL FULLER, CR SILCOX, RJ BROWN, DE AF METCALF, VL FULLER, CR SILCOX, RJ BROWN, DE TI ACTIVE CONTROL OF SOUND-TRANSMISSION RADIATION FROM ELASTIC PLATES BY VIBRATION INPUTS .2. EXPERIMENTS SO JOURNAL OF SOUND AND VIBRATION LA English DT Article C1 VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. RP METCALF, VL (reprint author), USA,LANGLEY RES CTR,AVSCOM,AVIAT RES & TECHNOL ACT,HAMPTON,VA 23665, USA. NR 6 TC 22 Z9 23 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD MAR 22 PY 1992 VL 153 IS 3 BP 387 EP 402 DI 10.1016/0022-460X(92)90372-5 PG 16 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA HL113 UT WOS:A1992HL11300001 ER PT J AU GABUZDA, DC CAWTHORNE, TV ROBERTS, DH WARDLE, JFC AF GABUZDA, DC CAWTHORNE, TV ROBERTS, DH WARDLE, JFC TI A SURVEY OF THE MILLIARCSECOND POLARIZATION PROPERTIES OF BL LACERTAE OBJECTS AT 5 GHZ SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL LACERTAE OBJECTS, GENERAL; GALAXIES, JETS; GRAVITATIONAL LENSING; POLARIZATION; RADIO CONTINUUM, GALAXIES ID SPECTRUM RADIO-SOURCES; LINEAR-POLARIZATION; LAC OBJECTS; RESOLUTION; OJ-287; MAPS; VLBI; AO-0235+164; ARTIFACTS; EMISSION AB Milliarcsecond resolution total intensity and linear polarization maps at 5 GHz are presented for 11 BL Lacertae objects, 10 of which have never before been mapped with polarization sensitivity and six of which have never before been mapped using VLBI. There are now 18 BL Lacertae objects for which information about the polarization of the emission on VLBI scales is available. In every BL Lacertae object in which we have detected polarization structure (0454 + 844, 0735 + 178, OJ287, 0954 + 658, 1219 + 285, 1538 + 149, 1803 + 784, 1823 + 568, and BL Lac), the polarization position angle in the knots is nearly parallel to the VLBI structural axis. In contrast, the direction of polarization in the cores of these sources appears to be random. One likely explanation for the preferred polarization direction in the jets is that plane perpendicular shock waves are common in these sources; the origin of the absence of preferred polarization direction in the core components is not clear. These results strengthen our earlier conclusion that it cannot be the case that a significant number of BL Lacertae objects are gravitationally microlensed images of more distant quasars, since the characteristic VLBI polarization structures observed in these two types of object are very different. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. BRANDEIS UNIV,DEPT PHYS,WALTHAM,MA 02254. RP GABUZDA, DC (reprint author), UNIV CALGARY,DEPT PHYS & ASTRON,CANADIAN NETWORK SPACE RES,2500 UNIV DR NW,CALGARY T2N 1N4,ALBERTA,CANADA. NR 52 TC 113 Z9 113 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 MAR 20 PY 1992 VL 388 IS 1 BP 40 EP 54 DI 10.1086/171128 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK566 UT WOS:A1992HK56600006 ER PT J AU WANG, ZR QU, QY LUO, D MCCRAY, R MACLOW, MM AF WANG, ZR QU, QY LUO, D MCCRAY, R MACLOW, MM TI THE SEMICIRCULAR SHELL OF CTB-109 SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERSTELLAR, MATTER; NEBULAE, INDIVIDUAL (CTB-109); NEBULAE, SUPERNOVA REMNANTS; X-RAYS, SOURCES ID X-RAY PULSAR; SUPERNOVA REMNANT G109.1-1.0; RADIO OBSERVATIONS; 1E 2259+586; EXTRAORDINARY; SUPERBUBBLES; PLASMA; CLOUD AB The radio and X-ray images of the supernova remnant CTB 109 have the morphology of a semicircular shell. We show that such a structure is a natural result of a supernova explosion (with energy E = 3.6 x 10(50) ergs) that occurred 1.3 x 10(4) yr ago near an interface between the diffuse (density n0 = 0.13 cm-3) interstellar medium and a dense (n(c),0 = 36 cm-3) molecular cloud. The calculated X-ray, infrared, and radio fluxes agree fairly well with the observed values. C1 NANJING UNIV,DEPT ASTRON,NANJING,PEOPLES R CHINA. UNIV COLORADO,NATL INST STAND & TECHNOL,JOINT INST LAB ASTROPHYS,BOULDER,CO 80302. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP WANG, ZR (reprint author), CHINA CTR ADV SCI & TECHNOL,CTR ASTRON & ASTROPHYS,NANJING,PEOPLES R CHINA. OI Mac Low, Mordecai-Mark/0000-0003-0064-4060 NR 34 TC 19 Z9 20 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 MAR 20 PY 1992 VL 388 IS 1 BP 127 EP 130 DI 10.1086/171134 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK566 UT WOS:A1992HK56600012 ER PT J AU DAR, A KOZLOVSKY, BZ NUSSINOV, S RAMATY, R AF DAR, A KOZLOVSKY, BZ NUSSINOV, S RAMATY, R TI GAMMA-RAY BURSTS AND COSMIC-RAYS FROM ACCRETION-INDUCED COLLAPSE SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; COSMIC RAYS; ELEMENTARY PARTICLES; GAMMA-RAYS, BURSTS; STARS, NEUTRON ID STELLAR-CORE COLLAPSE; NEUTRON-STARS; SUPERNOVA; ANNIHILATION; GALAXIES; PULSARS AB Accretion of matter onto the surface of a white dwarf in a binary system can push it over the Chandrasekhar mass limit and may cause it to collapse into a naked or nearly naked neutron star without detectable optical emission. Such ali optically quiet neutron star birth should be accompanied by a neutrino burst which could be detected with underground neutrino detectors only if the collapse took place in our own Galaxy or in very close nearby galaxies. However, neutrino-antineutrino annihilation outside the neutron star into electron-positron pairs will produce a gamma-ray burst that can be observed out to distances of at least 300 Mpc, if the mass surrounding the newly formed neutron star is less than about 3 x 10(-4) M.. If the surrounding mass is between approximately 3 x 10(-4) M. and approximately 0.1 M., it will be injected into the interstellar space with energy above 10 meV per nucleon. Such nonrelativistic nuclei can be further accelerated to cosmic-ray energies in the interstellar space before they slow down by collisions. Thus, accretion-induced collapse may be an important source of cosmic rays and of cosmological gamma-ray bursts. Conversely, the observed rate of gamma-ray bursts and cosmic-ray data can be used to limit the birthrate of naked, or nearly naked, neutron stars to less than one per 10(3) yr in galaxies similar to ours. This rate is too small to contribute significantly to the birthrate of pulsars, and it implies that it is very unlikely that a neutrino burst unaccompanied by optical emission will be detected in the near future by the underground neutrino detectors. C1 TECHNION ISRAEL INST TECHNOL,DEPT PHYS,IL-32000 HAIFA,ISRAEL. TECHNION ISRAEL INST TECHNOL,SPACE RES INST,IL-32000 HAIFA,ISRAEL. TEL AVIV UNIV,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. RP DAR, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 35 TC 55 Z9 55 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 MAR 20 PY 1992 VL 388 IS 1 BP 164 EP 170 DI 10.1086/171138 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK566 UT WOS:A1992HK56600016 ER PT J AU KOPP, G LINDSEY, C ROELLIG, TL WERNER, MW BECKLIN, EE ORRALL, FQ JEFFERIES, JT AF KOPP, G LINDSEY, C ROELLIG, TL WERNER, MW BECKLIN, EE ORRALL, FQ JEFFERIES, JT TI CHROMOSPHERIC DYNAMICS BASED ON INFRARED SOLAR BRIGHTNESS VARIATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, CHROMOSPHERE; SUN, OSCILLATIONS ID WAVES; ATMOSPHERE; OSCILLATIONS; PROPAGATION; SUN AB We used the NASA Kuiper Airborne Observatory to observe far-infrared continuum brightness fluctuations in the lower chromosphere due to solar 5 minute oscillations on the quiet Sun. Brightness measurements made at 50, 100, 200, and 400-mu-m show a strong correlation with visible-line Doppler measurements from photospheric and chromospheric altitudes. The motion of the chromosphere is nearly in phase over a large range of heights, while the infrared brightness lags the Doppler velocity by phases varying from significantly less than 90-degrees at low altitudes to nearly 90-degrees at higher altitudes. We propose that this is the result of a nonadiabatic response of the chromospheric gas to compression and may indicate an important mechanism for wave dissipation. We estimate thermal relaxation times ranging from about 40 s at 340 km above the tau-5000 = 1 photosphere to approximately 300 s at 600 km. C1 STANFORD UNIV, STANFORD, CA 94305 USA. UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP NATL SOLAR OBSERV, POB 26732, TUCSON, AZ 85726 USA. NR 28 TC 8 Z9 8 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 MAR 20 PY 1992 VL 388 IS 1 BP 203 EP 210 DI 10.1086/171144 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK566 UT WOS:A1992HK56600022 ER PT J AU LICHTEN, SM MARCUS, SL DICKEY, JO AF LICHTEN, SM MARCUS, SL DICKEY, JO TI SUB-DAILY RESOLUTION OF EARTH ROTATION VARIATIONS WITH GLOBAL POSITIONING SYSTEM MEASUREMENTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GPS ORBIT AB Data from a worldwide Global Positioning System (GPS) tracking experiment have been used to determine variations in Earth rotation (UT1-UTC) over a time period of three weeks. Kalman filtering and smoothing enabled changes in UT1-UTC over intervals of 2 to 24 hrs to be detected with the GPS data. Internal consistency checks and comparisons with other solutions from very long baseline interferometry (VLBI) and satellite laser ranging (SLR) indicate that the GPS UT1-UTC estimates are accurate to about 2 cm. Comparison of GPS-estimated variations in UT1-UTC with 2-hr time resolution over 4 days with predicted variations computed from diurnal and semi-diurnal oceanic tidal contributions strongly suggests that the observed periodic sub-daily variations of approximately 0.1 msec (5 cm) are largely of tidal origin. RP LICHTEN, SM (reprint author), CALTECH,JET PROP LAB,238-625,4800 OAK GROVE DR,PASADENA,CA 91109, USA. OI Marcus, Steven/0000-0002-5763-6961 NR 21 TC 22 Z9 22 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 MAR 20 PY 1992 VL 19 IS 6 BP 537 EP 540 DI 10.1029/92GL00563 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HK981 UT WOS:A1992HK98100004 ER PT J AU VANZYL, JJ BURNETTE, CF AF VANZYL, JJ BURNETTE, CF TI BAYESIAN CLASSIFICATION OF POLARIMETRIC SAR IMAGES USING ADAPTIVE A-PRIORI PROBABILITIES SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article AB Most implementations of Bayesian classification assume fixed a priori probabilities. These implementations can be placed into two general categories: (1) those that assume equal a priori probabilities and (2) those that assume unequal but fixed a priori probabilities. We report here on results of classifying polarimetric SAR images using a scheme in which the classification is done iteratively. The first classification is done assuming fixed (but not necessarily equal) a priori probabilities. The results of this first classification are then used in successive iterations to change the a priori probabilities adaptively. The results show that only a few iterations are necessary to improve the classification accuracy dramatically. RP VANZYL, JJ (reprint author), CALTECH,JET PROP LAB,MAIL STOP 300-233,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 6 TC 49 Z9 49 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAR 20 PY 1992 VL 13 IS 5 BP 835 EP 840 PG 6 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA HL676 UT WOS:A1992HL67600003 ER PT J AU CIBULA, WG CARTER, GA AF CIBULA, WG CARTER, GA TI IDENTIFICATION OF A FAR-RED REFLECTANCE RESPONSE TO ECTOMYCORRHIZAE IN SLASH PINE SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Letter ID SPECTRAL REFLECTANCE; REMOTE; MYCORRHIZAE; VEGETATION; ECOLOGY; PLANTS; SOIL; OAK AB Spectral reflectances were measured for the canopies of Pinus elliottii seedlings that were inoculated versus non-inoculated with the ectomycorrhizal fungus Pisolithus tinctorius. Reflectances of the less vigorous, non-inoculated seedlings increased substantially at visible and near-infrared wavelengths compared to the more vigorous, inoculated seedlings. An algorithm was developed to indicate the spectral regions in which reflectance was most sensitive to ectomycorrhizae. The reflectance curve of the more vigorous seedlings was used as a standard of comparison. We denote the spectral regions defined by this algorithm as regions of maximum reflectance sensitivity. Far-red and near-infrared photography filtered to the region of maximum sensitivity (700 nm) were used to enable visualization of a 'blue shift' reflectance response to decreased vigour in the non-inoculated seedlings in response to these differences of mycorrhizal development. RP CIBULA, WG (reprint author), NASA,SCI & TECHNOL LAB,BAY ST LOUIS,MS 39529, USA. NR 27 TC 40 Z9 42 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAR 20 PY 1992 VL 13 IS 5 BP 925 EP 932 PG 8 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA HL676 UT WOS:A1992HL67600011 ER PT J AU RANDALL, DA CESS, RD BLANCHET, JP BOER, GJ DAZLICH, DA DELGENIO, AD DEQUE, M DYMNIKOV, V GALIN, V GHAN, SJ LACIS, AA LETREUT, H LI, ZX LIANG, XZ MCAVANEY, BJ MELESHKO, VP MITCHELL, JFB MORCRETTE, JJ POTTER, GL RIKUS, L ROECKNER, E ROYER, JF SCHLESE, U SHEININ, DA SLINGO, J SOKOLOV, AP TAYLOR, KE WASHINGTON, WM WETHERALD, RT YAGAI, I ZHANG, MH AF RANDALL, DA CESS, RD BLANCHET, JP BOER, GJ DAZLICH, DA DELGENIO, AD DEQUE, M DYMNIKOV, V GALIN, V GHAN, SJ LACIS, AA LETREUT, H LI, ZX LIANG, XZ MCAVANEY, BJ MELESHKO, VP MITCHELL, JFB MORCRETTE, JJ POTTER, GL RIKUS, L ROECKNER, E ROYER, JF SCHLESE, U SHEININ, DA SLINGO, J SOKOLOV, AP TAYLOR, KE WASHINGTON, WM WETHERALD, RT YAGAI, I ZHANG, MH TI INTERCOMPARISON AND INTERPRETATION OF SURFACE-ENERGY FLUXES IN ATMOSPHERIC GENERAL-CIRCULATION MODELS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLIMATE FEEDBACK; CLOUD AB We have analyzed responses of the surface energy budgets and hydrologic cycles of 19 atmospheric general circulation models to an imposed, globally uniform sea surface temperature perturbation of 4 K. The responses of the simulated surface energy budgets are extremely diverse and are closely linked to the responses of the simulated hydrologic cycles. The response of the net surface energy flux is not controlled by cloud effects; instead, it is determined primarily by the response of the latent heat flux. The prescribed warming of the oceans leads to major increases in the atmospheric water vapor content and the rates of evaporation and precipitation. The increased water vapor amount drastically increases the downwelling infrared radiation at the Earth's surface, but the amount of the change varies dramatically from one model to another. C1 DEPT ENVIRONM, CANADIAN CLIMATE CTR, ATMOSPHER ENVIRONM SERV, 4905 DUFFERIN ST, TORONTO M3H 5T4, ONTARIO, CANADA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. SUNY STONY BROOK, INST TERR & PLANETARY ATMOSPHERES, STONY BROOK, NY 11794 USA. NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. CTR NATL RECH METEOROL, DIRECT METEOROL, TOULOUSE, FRANCE. ACAD SCI USSR, DEPT NUMER MATH, MOSCOW V-71, USSR. UNIV CALIF LAWRENCE LIVERMORE NATL LAB, PROGRAM CLIMATE MODEL DIAG & INTERCOMPARISON, LIVERMORE, CA 94550 USA. LAB METEOROL DYNAM, PARIS, FRANCE. SUNY STONY BROOK, DEPT MECH ENGN, STONY BROOK, NY 11794 USA. BUR METEOROL RES CTR, MELBOURNE, VIC, AUSTRALIA. VOEIKOV MAIN GEOPHYS OBSERV, ST PETERSBURG, USSR. METEOROL OFF, BRACKNELL, BERKS, ENGLAND. EUROPEAN CTR MEDIUM RANGE WEATHER FORECASTS, READING, BERKS, ENGLAND. PRINCETON UNIV, NOAA, GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08544 USA. METEOROL RES INST, IBARAKI, JAPAN. UNIV HAMBURG, INST METEOROL, W-2000 HAMBURG 13, GERMANY. UNIV READING, DEPT METEOROL, READING RG6 2AH, BERKS, ENGLAND. NATL CTR ATMOSPHER RES, DIV CLIMATE & GLOBAL DYNAM, BOULDER, CO 80307 USA. RI Taylor, Karl/F-7290-2011; Del Genio, Anthony/D-4663-2012; Lacis, Andrew/D-4658-2012; Randall, David/E-6113-2011; Meleshko, Valentin/D-2157-2016; Ghan, Steven/H-4301-2011; OI Taylor, Karl/0000-0002-6491-2135; Del Genio, Anthony/0000-0001-7450-1359; Randall, David/0000-0001-6935-4112; Ghan, Steven/0000-0001-8355-8699; Li, Laurent/0000-0002-3855-3976 NR 23 TC 79 Z9 79 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1992 VL 97 IS D4 BP 3711 EP 3724 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HK021 UT WOS:A1992HK02100002 ER PT J AU CAHOON, DR STOCKS, BJ LEVINE, JS COFER, WR CHUNG, CC AF CAHOON, DR STOCKS, BJ LEVINE, JS COFER, WR CHUNG, CC TI EVALUATION OF A TECHNIQUE FOR SATELLITE-DERIVED AREA ESTIMATION OF FOREST-FIRES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICS AB Satellite data have been used increasingly during the past few years to examine burning around the globe. One such satellite instrument, the advanced very high resolution radiometer (AVHRR), has been found useful for the location and monitoring of both smoke and fires because of the daily observations, the large geographical coverage of the imagery, the spectral characteristics of the instrument, and the spatial resolution of the instrument. Earlier studies using AVHRR imagery have focused on locating and monitoring fires and studying the characteristics of smoke. This paper will discuss the application of AVHRR data to assess the geographical extent of burning. Methods have been developed to estimate the surface area of burning by analyzing the surface area effected by fire with AVHRR imagery. Characteristics of the AVHRR instrument, its orbit, field of view, and archived data sets are discussed relative to the unique surface area of each pixel. The errors associated with this surface area estimation technique are determined using AVHRR-derived area estimates of target regions with known sizes. This technique is used to evaluate the area burned during the Yellowstone fires of 1988. C1 FORESTRY CANADA, FOREST FIRE RES, GREAT LAKES FORESTRY CTR, SAULT ST MARIE P6A SM7, ONTARIO, CANADA. UNIV PENN, DEPT PHYS, PHILADELPHIA, PA 19104 USA. RP CAHOON, DR (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL CODE 423, HAMPTON, VA 23665 USA. NR 18 TC 39 Z9 41 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1992 VL 97 IS D4 BP 3805 EP 3814 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HK021 UT WOS:A1992HK02100009 ER PT J AU PORTER, JN CLARKE, AD FERRY, G PUESCHEL, RF AF PORTER, JN CLARKE, AD FERRY, G PUESCHEL, RF TI AIRCRAFT STUDIES OF SIZE-DEPENDENT AEROSOL SAMPLING THROUGH INLETS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLIMATE; SULFUR; MODEL AB Accurate measurement of atmospheric aerosol from aircraft platforms is of importance to a variety of research interests. Representative measurement of aerosol from aircraft-aspirated systems requires special efforts in order to (1) maintain near isokinetic sampling conditions, (2) estimate aerosol losses in the sample system, and (3) obtain a measurement of sufficient duration to be statistically significant for all sizes of interest. This last point is especially critical for aircraft measurements which typically require fast response times while sampling in clean remote regions. Here we present size-resolved tests, intercomparisons, and analysis of aerosol inlet performance as determined by a custom laser optical counter. Measurements discussed here took place during the Global Backscatter Experiment (1988-1989) and the Central Pacific Atmospheric Chemistry Experiment (1988). System configurations are discussed including (1) nozzle design and performance, (2) system transmission efficiency, (3) nonadiabatic effects in the sample line and its effect on sample line relative humidity, and (4) the use and calibration of a virtual impactor. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP PORTER, JN (reprint author), UNIV HAWAII, SCH OCEAN & EARTH SCI & TECHNOL, 1000 POPE RD, HONOLULU, HI 96822 USA. NR 22 TC 35 Z9 35 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 1992 VL 97 IS D4 BP 3815 EP 3824 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HK021 UT WOS:A1992HK02100010 ER PT J AU KING, TVV CLARK, RN CALVIN, WM SHERMAN, DM BROWN, RH AF KING, TVV CLARK, RN CALVIN, WM SHERMAN, DM BROWN, RH TI EVIDENCE FOR AMMONIUM-BEARING MINERALS ON CERES SO SCIENCE LA English DT Article ID MARS AB Spectra obtained from recent telescopic observation of 1-Ceres and laboratory measurements and theoretical calculations of three component mixtures of Ceres analog material suggest that an ammoniated phyllosilicate is present on the surface of the asteroid, rather than H2O frost as had been previously reported. The presence of an ammoniated phyllosilicate, most likely ammoniated saponite, on the surface of Ceres implies that secondary temperatures could not have exceeded 400 kelvin. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP KING, TVV (reprint author), US GEOL SURVEY,DENVER,CO 80225, USA. RI Sherman, David/A-7538-2008 OI Sherman, David/0000-0003-1835-6470 NR 17 TC 69 Z9 69 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 MAR 20 PY 1992 VL 255 IS 5051 BP 1551 EP 1553 DI 10.1126/science.255.5051.1551 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HJ809 UT WOS:A1992HJ80900033 PM 17820166 ER PT J AU CHATFIELD, DC FRIEDMAN, RS SCHWENKE, DW TRUHLAR, DG AF CHATFIELD, DC FRIEDMAN, RS SCHWENKE, DW TRUHLAR, DG TI CONTROL OF CHEMICAL-REACTIVITY BY QUANTIZED TRANSITION-STATES SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID MECHANICAL REACTION PROBABILITIES; POTENTIAL-ENERGY SURFACE; PHASE-SPACE BOTTLENECKS; PATH HAMILTONIAN MODEL; QUANTAL RATE CONSTANTS; THERMAL RATE CONSTANTS; PHOTODETACHMENT SPECTRUM; TUNNELING CALCULATIONS; COLLINEAR REACTIONS; + H AB We review the basic principles of quantized transition state control of microcanonical ensemble rate constants and state-selected rate constants. Selected examples are presented for the H + H-2 and O + H-2 reactions. The following aspects are emphasized: (i) We can calculate accurate quantal microcanonical rate constants up to high energies. (ii) These rate constants show resolvable structure which may be attributed to quantized transition states. (iii) The energy dependence of the microcanonical rate constants can be explained quantitatively using a transition state plus tunneling model based on these quantized transition states. (iv) Fitting the model of quantized transition states plus tunneling to the accurate quantum dynamics yields energies, transmission coefficients, and effective barrier widths for individual energy levels of the transition state. (v) The energy level spectrum can be assigned using the conventional model for a complex with a missing degree of freedom. The spectrum is in good agreement with that predicted by the adiabatic theory of reactions or variational transition state theory. The deviations may provide a quantitative test of approximations typically involved in such calculations, e.g., neglect of anharmonic mode couplings. (vi) The individual transmission coefficients show that the quantitative errors in transition state theory (about 10% at the highest energy considered) result from large breakdowns for a few bend-excited levels rather than from small (say 10%) breakdowns for all transition state levels. (vii) The transition state effective barrier widths can be understood both in terms of the barrier widths of vibrationally adiabatic potential curves and in terms of resonance theory. (vii) Transition state resonance theory also allows predictions of transition state lifetimes on the basis of fits to the energy derivative of the microcanonical rate constant. (ix) We can calculate half-collision transition probabilities for specific reactant states to proceed to particular states of the activated complex and for particular states of the activated complex to proceed to specific states of the products; this allows for a very detailed picture of how state-to-state reactions occur. (x) The analysis of state-selected reactivity in terms of passage through particular transition states explains trends in the dependence of rate constants on initial vibrational and rotational quantum numbers. C1 UNIV MINNESOTA, DEPT CHEM, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. UNIV MINNESOTA, ARMY HIGH PERFORMANCE COMP RES CTR, MINNEAPOLIS, MN 55455 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 120 TC 90 Z9 91 U1 2 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD MAR 19 PY 1992 VL 96 IS 6 BP 2414 EP 2421 DI 10.1021/j100185a007 PG 8 WC Chemistry, Physical SC Chemistry GA HK717 UT WOS:A1992HK71700007 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H LANGHOFF, SR AF BAUSCHLICHER, CW PARTRIDGE, H LANGHOFF, SR TI THEORETICAL-STUDY OF CR+ AND CO+ BOUND TO H-2 AND N2 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; GTO BASIS-SETS; MOLECULAR CALCULATIONS; 2ND-ROW ATOMS; ROW ATOMS; N-2; CONTRACTION; 1ST-ROW; ENERGY AB Binding energies of Co(H2)n+ (n = 1-3) and CrN2+ computed using the modified coupled-pair functional approach agree well with measured values. The calculations show that both H-2 and N2 bond much more strongly to Co+ than to Cr+. Theoretical studies also show that despite the similar polarizabilities of N2 and Ar, the CrN2+ binding energy is twice as large as that of CrAr+ due to the charge-quadrupole contribution. Finally, the bonding of H-2 and N2 with Na+ and Mg+ is contrasted with that for Cr+ and Co+. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 33 TC 68 Z9 68 U1 1 U2 6 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 MAR 19 PY 1992 VL 96 IS 6 BP 2475 EP 2479 DI 10.1021/j100185a017 PG 5 WC Chemistry, Physical SC Chemistry GA HK717 UT WOS:A1992HK71700017 ER PT J AU FELTEN, JE DWEK, E AF FELTEN, JE DWEK, E TI NAPOLEON HAT SO NATURE LA English DT Letter RP FELTEN, JE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 685,GREENBELT,MD 20771, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAR 19 PY 1992 VL 356 IS 6366 BP 202 EP 202 DI 10.1038/356202a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HJ944 UT WOS:A1992HJ94400038 ER PT J AU GILLE, J LARIMER, J PIANTANIDA, T LANHAM, J AF GILLE, J LARIMER, J PIANTANIDA, T LANHAM, J TI ADDITIVE EFFECTS IN HUE CANCELLATION FOR INCREMENTS AND DECREMENTS ON BINOCULARLY FUSED ADAPTING FIELDS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SRI INT,MENLO PK,CA 94025. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 705 EP 705 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13500064 ER PT J AU AHUMADA, AJ AF AHUMADA, AJ TI COMPETITIVE LEARNING AND RED-GREEN OPPONENCY SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 755 EP 755 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13500311 ER PT J AU HEEGER, DJ AF HEEGER, DJ TI MODELING SIMPLE CELL DIRECTION SELECTIVITY WITH NORMALIZED, HALF-SQUARED, LINEAR-OPERATORS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 4 TC 4 Z9 4 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 953 EP 953 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13501304 ER PT J AU THOMPSON, P STONE, LS STONE, R AF THOMPSON, P STONE, LS STONE, R TI CONTRAST-DEPENDENCE OF SPEED PERCEPTION - EFFECTS OF TEMPORAL PRESENTATION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV YORK,DEPT PSYCHOL,YORK YO1 5DD,N YORKSHIRE,ENGLAND. NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 1 TC 2 Z9 2 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 973 EP 973 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13501408 ER PT J AU WATSON, AB AF WATSON, AB TI MOTION POOLING AREAS ESTIMATED FROM MOTION-CONTRAST SENSITIVITY FUNCTIONS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 2 Z9 2 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 974 EP 974 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13501410 ER PT J AU MULLIGAN, JB AF MULLIGAN, JB TI MOTION TRANSPARENCY IS RESTRICTED TO 2 PLANES SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 25 Z9 25 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1049 EP 1049 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13501786 ER PT J AU MOWAFY, L KAISER, MK AF MOWAFY, L KAISER, MK TI THE USE OF GLOBAL TAU FOR JUDGING THE TIME TO PASSAGE SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1140 EP 1140 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502232 ER PT J AU GILDEN, DL KAISER, MK AF GILDEN, DL KAISER, MK TI KINEMATIC SPECIFICATION OF DEPTH AND BOUNDARY SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract ID DIRECTION C1 VANDERBILT UNIV,NASHVILLE,TN 37240. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 3 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1141 EP 1141 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502241 ER PT J AU PERRONE, JA STONE, LS AF PERRONE, JA STONE, LS TI A POSSIBLE ROLE FOR THE SPEED TUNING PROPERTIES OF MT CELLS IN THE RECOVERY OF DEPTH FROM MOTION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 2 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1141 EP 1141 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502239 ER PT J AU MCBEATH, MK KAISER, MK AF MCBEATH, MK KAISER, MK TI VISUAL BIAS FOR GRAVITATIONALLY DOWNWARD MOTION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV AEROSPACE HUMAN FACTORS RES,MOFFETT FIELD,CA 94035. NR 0 TC 2 Z9 2 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1143 EP 1143 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502253 ER PT J AU MACKNIK, SL PELLIONISZ, AJ TOMKO, DL AF MACKNIK, SL PELLIONISZ, AJ TOMKO, DL TI SQUIRREL-MONKEY EYE ROTATION AXES DETERMINED BY EXTRAOCULAR-MUSCLE GEOMETRY SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NASA,AMES RES CTR,VESTIBULAR RES FACIL,MOFFETT FIELD,CA 94035. NR 2 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1150 EP 1150 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502289 ER PT J AU OLSHAUSEN, BA ANDERSON, CH VANESSEN, DC AF OLSHAUSEN, BA ANDERSON, CH VANESSEN, DC TI COMPUTER-SIMULATION OF A DYNAMIC ROUTING MODEL OF VISUAL-ATTENTION SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. CALTECH,PASADENA,CA 91125. NR 1 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1263 EP 1263 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13502844 ER PT J AU BOMAN, D GILLE, J PIANTANIDA, T LARIMER, J AF BOMAN, D GILLE, J PIANTANIDA, T LARIMER, J TI EFFECTS OF VISUAL-FIELD SIZE AND DISTRACTER ATTRIBUTES ON TARGET DETECTION IN VIRTUAL-REALITY SYSTEMS SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 SRI INT,MENLO PK,CA 94025. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 1992 VL 33 IS 4 BP 1416 EP 1416 PG 1 WC Ophthalmology SC Ophthalmology GA HK135 UT WOS:A1992HK13503610 ER PT J AU CHATFIELD, DC TRUHLAR, DG SCHWENKE, DW AF CHATFIELD, DC TRUHLAR, DG SCHWENKE, DW TI STATE-SELECTED CHEMICAL-REACTION DYNAMICS AT THE S-MATRIX LEVEL - FINAL-STATE SPECIFICITIES OF NEAR-THRESHOLD PROCESSES AT LOW AND HIGH-ENERGIES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VARIATIONAL-METHODS; CROSS-SECTIONS; COLLISIONS; VIBRATION; SURFACES; ROTATION AB State-to-state reaction probabilities are found to be highly final-state specific at state-selected threshold energies for the reactions O + H-2 --> OH + H and H + H-2 --> H-2 + H. The study includes initial rotational states with quantum numbers 0-15, and the specificity is especially dramatic for the more highly rotationally excited reactants. The analysis is based on accurate quantum mechanical reactive scattering calculations. Final-state specificity is shown in general to increase with the rotational quantum number of the reactant diatom, and the trends are confirmed for both zero and nonzero values of the total angular momentum. C1 UNIV MINNESOTA, ARMY HIGH PERFORMANCE COMP RES CTR, MINNEAPOLIS, MN 55455 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP CHATFIELD, DC (reprint author), UNIV MINNESOTA, INST SUPERCOMP, 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 31 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 15 PY 1992 VL 96 IS 6 BP 4313 EP 4323 DI 10.1063/1.462824 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HK019 UT WOS:A1992HK01900029 ER PT J AU BAUSCHLICHER, CW SODUPE, M PARTRIDGE, H AF BAUSCHLICHER, CW SODUPE, M PARTRIDGE, H TI A THEORETICAL-STUDY OF THE POSITIVE AND DIPOSITIVE IONS OF M(NH3)N AND M(H2O)N FOR M=MG, CA, OR SR SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GAUSSIAN-BASIS SETS; MOLECULAR CALCULATIONS; ROW ATOMS; 2ND-ROW ATOMS; ORBITALS; CONTRACTION AB The structure and binding energies are determined for many of the M(H2O)n+ and M(H2O)n2+ species, for n = 1-3 and M = Mg, Ca, or Sr. The trends are explained in terms of metal sp or sd-sigma-hybridization and core polarization. The M(NH3)n+ systems, with M = Mg or Sr, are also studied. For the positive ions, the low-lying excited states are also studied and compared with experiment. The calculations suggest an alternative interpretation of the SrNH3+ spectrum. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 31 TC 206 Z9 206 U1 0 U2 7 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 MAR 15 PY 1992 VL 96 IS 6 BP 4453 EP 4463 DI 10.1063/1.462808 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HK019 UT WOS:A1992HK01900044 ER PT J AU WHARTON, RA MCKAY, CP CLOW, GD ANDERSEN, DT SIMMONS, GM LOVE, FG AF WHARTON, RA MCKAY, CP CLOW, GD ANDERSEN, DT SIMMONS, GM LOVE, FG TI CHANGES IN ICE COVER THICKNESS AND LAKE LEVEL OF LAKE HOARE, ANTARCTICA - IMPLICATIONS FOR LOCAL CLIMATIC-CHANGE SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article AB We report results from 10 years of ice thickness measurements at perennially ice-covered Lake Hoare in southern Victoria Land, Antarctica. The ice cover of this lake had been thinning steadily at a rate exceeding 20 cm yr-1 during the last decade but seems to have recently stabilized at a thickness of 3.3 m. Data concerning lake level and degree-days above freezing are presented to show the relationship between peak summer temperatures and the volume of glacier-derived meltwater entering Lake Hoare each summer. From these latter data we infer that peak summer temperatures have been above 0-degrees-C for a progressively longer period of time each year since 1972. We also consider possible explanations for the thinning of the lake ice. The thickness of the ice cover is determined by the balance between freezing during the winter and ablation that occurs all year but maximizes in summer. We suggest that the term most likely responsible for the change in the ice cover thickness at Lake Hoare is the extent of summer melting, consistent with the rising lake levels. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. US GEOL SURVEY,ASTROGEOL BRANCH,MENLO PK,CA 94025. VIRGINIA POLYTECH INST & STATE UNIV,DEPT BIOL SCI,BLACKSBURG,VA 24061. RADFORD UNIV,DEPT GEOL,RADFORD,VA 24142. LOCKHEED ENGN & SCI CO,WASHINGTON,DC 20024. RP WHARTON, RA (reprint author), UNIV NEVADA SYST,DESERT RES INST,POB 60220,RENO,NV 89506, USA. NR 27 TC 35 Z9 35 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-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 1992 VL 97 IS C3 BP 3503 EP 3513 DI 10.1029/91JC03106 PG 11 WC Oceanography SC Oceanography GA HJ488 UT WOS:A1992HJ48800003 PM 11538388 ER PT J AU CHOI, SR SALEM, JA AF CHOI, SR SALEM, JA TI STRENGTH, TOUGHNESS AND R-CURVE BEHAVIOR OF SIC WHISKER-REINFORCED COMPOSITE SI3N4 WITH REFERENCE TO MONOLITHIC SI3N4 SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SILICON-CARBIDE; FRACTURE-TOUGHNESS; MATRIX COMPOSITES; MECHANICAL-PROPERTIES; TOUGHENING BEHAVIOR; ALUMINA; NITRIDE AB The flexural strength and fracture toughness of 30 vol% SiC whisker-reinforced Si3N4 material were determined as a function of temperature from 25 to 1400-degrees-C in an air environment. It was found that both strength and toughness of the composite material were almost the same as those of the monolithic counterpart. The room-temperature strength was retained up to 1100-degrees-C; however, appreciable strength degradation started at 1200-degrees-C and reached a maximum at 1400-degrees-C due to stable crack growth. In contrast, the fracture toughness of the two materials was independent of temperature with an average value of 5.66 MPa m1/2. It was also observed that the composite material exhibited no rising R-curve behaviour at room temperature, as was the case for the monolithic material. These results indicate that SiC whisker addition to the Si3N4 matrix did not provide any favourable effects on strength, toughness and R-curve behaviour. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP CHOI, SR (reprint author), CLEVELAND STATE UNIV,CLEVELAND,OH 44115, USA. NR 31 TC 12 Z9 12 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAR 15 PY 1992 VL 27 IS 6 BP 1491 EP 1498 DI 10.1007/BF00542909 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA HK024 UT WOS:A1992HK02400013 ER PT J AU HUNTER, SD CUDDAPAH, R AF HUNTER, SD CUDDAPAH, R TI NEW DRIFT CHAMBER ELECTRONICS FOR HIGH-ENERGY GAMMA-RAY TELESCOPES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The next generation gamma ray telescope is envisioned as a "2 meter class" instrument, a picture type detector using large area (2 m x 2 m) drift chambers for the imaging detector. Low power amplifier, discriminator and time-to-digital converter (TDC) circuits are crucial to the development of large area drift chambers for use in space where power is limited. We discuss the design for an amplifier, discriminator and quad TDC which will operate within an estimated power budget of 200 mW per anode for an instrument using large area drift chambers. The amplifier has a rise time of 6.3 ns, gain of 10.9 and 41 mW power. The discriminator has a 12 ns propagation time, 15 ns rise time, 25 ns pulse width and 25 mW power. The quad TDC has a power of 95 mW, 12 bit resolution and RMS error less than 0.2% full scale. RP HUNTER, SD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Hunter, Stanley/D-2942-2012 NR 11 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 15 PY 1992 VL 313 IS 3 BP 506 EP 512 DI 10.1016/0168-9002(92)90831-N PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HL486 UT WOS:A1992HL48600027 ER PT J AU GEHRELS, N AF GEHRELS, N TI INSTRUMENTAL BACKGROUND IN GAMMA-RAY SPECTROMETERS FLOWN IN LOW EARTH ORBIT SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ASTRONOMY; SPACEFLIGHT AB Techniques are presented for calculating the instrumental continuum background in gamma-ray spectrometers flown in low Earth orbit. Simple methods are developed for scaling from the better-understood measurements and calculations of background in balloon-borne instruments. Secondary radiations are found to scale with the parameter E0.7 defined as the integral of the particle energy raised to the 0.7 power times the incident proton spectrum. The new scaling methods give background results for the HEAO 3 gamma-ray spectrometer that compare well with measurements. The key results are predictions of the background, sensitivity and orbit effects for future spaceborne high-resolution gamma-ray spectrometers. The background for these instruments will be highly dominated from 0.1 to 2 MeV by the beta-decay component. Detector segmentation and pulse-shape discrimination beta-rejection techniques will therefore be critically important. Loss of observing time and sensitivity due to activation by trapped particles in the South Atlantic Anomaly (SAA) is strongly dependent on orbit inclination and altitude. The largest losses occur between 0.2 and 1.0 MeV. For the scientifically important energy range near 0.6 MeV, a 28-degrees, 500 km orbit has up to 70% loss of observing time. For a 28-degrees inclination orbit, acceptable time loss of less than 50% can only be achieved by flying under the SAA in a 300-400 km orbit. To reduce data loss to less than 20%, the > 250 MeV trapped proton daily fluence must be less than 2 x 10(4) proton cm-2, which occurs for orbits with inclinations less than 20-degrees for 400 km altitude and less than 15-degrees for 500 km altitude. RP GEHRELS, N (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Gehrels, Neil/D-2971-2012 NR 42 TC 41 Z9 44 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 15 PY 1992 VL 313 IS 3 BP 513 EP 528 DI 10.1016/0168-9002(92)90832-O PG 16 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HL486 UT WOS:A1992HL48600028 ER PT J AU BRAND, HR DEISSLER, RJ AF BRAND, HR DEISSLER, RJ TI ECKHAUS AND BENJAMIN-FEIR INSTABILITIES NEAR A WEAKLY INVERTED BIFURCATION SO PHYSICAL REVIEW A LA English DT Article ID GINZBURG-LANDAU EQUATION; CONVECTIVE INSTABILITY; TRAVELING WAVES; PATTERNS; SYSTEMS; MIXTURE; STATES AB We investigate how the criteria for two prototype instabilities in one-dimensional pattern-forming systems, namely for the Eckhaus instability and for the Benjamin-Feir instability, change as one goes from a continuous bifurcation to a spatially periodic or spatially and/or time-periodic state to the corresponding weakly inverted, i.e., hysteretic, cases. We also give the generalization to two-dimensional patterns in systems with anisotropy as they arise, for example, for hydrodynamic instabilities in nematic liquid crystals. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. NASA,LEWIS RES CTR,INST COMPUTAT MECH PROP,CLEVELAND,OH 44135. RP BRAND, HR (reprint author), UNIV ESSEN GESAMTHSCH,FACHBEREICH PHYS 7,W-4300 ESSEN 1,GERMANY. NR 35 TC 11 Z9 11 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR 15 PY 1992 VL 45 IS 6 BP 3732 EP 3736 DI 10.1103/PhysRevA.45.3732 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HK384 UT WOS:A1992HK38400043 ER PT J AU MOLLERACH, S MATARRESE, S AF MOLLERACH, S MATARRESE, S TI NONSCALE-INVARIANT DENSITY PERTURBATIONS FROM CHAOTIC EXTENDED INFLATION SO PHYSICAL REVIEW D LA English DT Article ID NONSTANDARD PRIMORDIAL FLUCTUATIONS; COSMOLOGICAL PERTURBATIONS; GENERAL-RELATIVITY; TENSOR THEORY; UNIVERSE; GRAVITY; VARIABILITY; CONSTANT; SPECTRA; FIELD AB Chaotic inflation is analyzed in the frame of scalar-tensor theories of gravity. Fluctuations in the energy density arise from quantum fluctuations of the Brans-Dicke field and of the inflaton field. The spectrum of perturbations is studied for a class of models: it is non-scale-invariant and, for certain values of the parameters, it has a peak. If the peak appears at astrophysically interesting scales it may help to reconcile the cold-dark-matter scenario for structure formation with large-scale observations. C1 UNIV PADUA,DIPARTIMENTO FIS GALILEO GALILEI,I-35131 PADUA,ITALY. RP MOLLERACH, S (reprint author), NASA,FERMILAB ASTROPHYS CTR,POB 500,BATAVIA,IL 60510, USA. NR 57 TC 21 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 15 PY 1992 VL 45 IS 6 BP 1961 EP 1970 DI 10.1103/PhysRevD.45.1961 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HJ691 UT WOS:A1992HJ69100011 ER PT J AU BOZZOLO, G FERRANTE, J AF BOZZOLO, G FERRANTE, J TI A NEW APPROXIMATE SUM-RULE FOR BULK ALLOY PROPERTIES SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID UNIVERSAL FEATURES; ELECTRONIC THEORY; PHASE-STABILITY; METALS; AG; AU C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP BOZZOLO, G (reprint author), ANALEX CORP,3001 AEROSP PKWY,BROOK PK,OH 44142, USA. NR 11 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR 15 PY 1992 VL 26 IS 6 BP 907 EP 912 DI 10.1016/0956-716X(92)90680-D PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HH634 UT WOS:A1992HH63400008 ER PT J AU WHITTENBERGER, JD REVIERE, R NOEBE, RD OLIVER, BF AF WHITTENBERGER, JD REVIERE, R NOEBE, RD OLIVER, BF TI COMPRESSIVE STRENGTH OF DIRECTIONALLY SOLIDIFIED NIAL-NIALNB INTERMETALLICS AT 1200-K AND 1300-K SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID PLASTIC-FLOW PROPERTIES; TEMPERATURE C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. RP WHITTENBERGER, JD (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 15 TC 18 Z9 18 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAR 15 PY 1992 VL 26 IS 6 BP 987 EP 992 DI 10.1016/0956-716X(92)90695-B PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HH634 UT WOS:A1992HH63400023 ER PT J AU DELLACORTE, C PEPPER, SV HONECY, FS AF DELLACORTE, C PEPPER, SV HONECY, FS TI TRIBOLOGICAL PROPERTIES OF AG/TI FILMS ON AL2O3 CERAMIC SUBSTRATES SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 18TH INTERNATIONAL CONF ON METALLURGICAL COATINGS AND THIN FILMS CY APR 22-26, 1991 CL SAN DIEGO, CA ID ALUMINA; WEAR AB Silver solid lubricant films with a thin titanium interlayer for enhanced adhesion, were sputter deposited on Al2O3 substrate disks to reduce friction and wear. The dual Ag/Ti films were tested at room temperature in a pin-on-disk tribometer sliding against bare, uncoated Al2O3 pins under a load of 4.9 N at a sliding velocity of 1 m s-1. The Ag/Ti films reduced the friction coefficient by 50% to about 0.42 compared to unlubricated baseline specimens. Pin wear was reduced by a factor of 140 and disk wear was reduced by a factor of 2.5 compared to the baseline. These films retain their good tribological properties, including adhesion, after heat treatment in argon at 850 C and thus may be able to lubricate over a wide temperature range. This lubrication technique is applicable to space lubrication, advanced heat engines and advanced transportation systems. RP DELLACORTE, C (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 17 Z9 19 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD MAR 15 PY 1992 VL 52 IS 1 BP 31 EP 37 DI 10.1016/0257-8972(92)90368-K PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HK481 UT WOS:A1992HK48100004 ER PT J AU SEN, AD ANICICH, VG ARAKELIAN, T AF SEN, AD ANICICH, VG ARAKELIAN, T TI DIELECTRIC-CONSTANT OF LIQUID ALKANES AND HYDROCARBON MIXTURES SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID TITAN; PHOTOCHEMISTRY AB The complex dielectric constants of n-alkanes with two to seven carbon atoms have been measured. The measurements were conducted using a slotted-line technique at 1.2 GHz and at atmospheric pressure. The temperature was varied from the melting point to the boiling point of the respective alkanes. The real part of the dielectric constant was found to decrease with increasing temperature and correlate with the change in the molar volume. An upper limit to all the loss tangents was established at 0.001. The complex dielectric constants of a few mixtures of liquid alkanes were also measured at room temperature. For a pentane-octane mixture the real part of the dielectric constant could be explained by the Clausius-Mosotti theory. For the mixtures of n-hexane-ethylacetate and n-hexane-acetone the real part of the dielectric constants could be explained by the Onsager theory extended to mixtures. The dielectric constant of the n-hexane-acetone mixture displayed deviations from the Onsager theory at the highest fractions of acetone. The dipole moments of ethylacetate and acetone were determined for dilute mixtures using the Onsager theory and were found to be in agreement with their accepted gas-phase values. The loss tangents of the mixtures exhibited a linear relationship with the volume fraction for low concentrations of the polar liquids. RP SEN, AD (reprint author), CALTECH,JET PROP LAB,MAIL STOP 183-601,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 19 TC 31 Z9 31 U1 4 U2 14 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD MAR 14 PY 1992 VL 25 IS 3 BP 516 EP 521 DI 10.1088/0022-3727/25/3/027 PG 6 WC Physics, Applied SC Physics GA HJ750 UT WOS:A1992HJ75000027 PM 11538383 ER PT J AU KARLSSON, KR CLAYTON, RN GIBSON, EK MAYEDA, TK AF KARLSSON, KR CLAYTON, RN GIBSON, EK MAYEDA, TK TI WATER IN SNC METEORITES - EVIDENCE FOR A MARTIAN HYDROSPHERE SO SCIENCE LA English DT Article ID ANTARCTIC SHERGOTTITE; NOBLE-GASES; MARS; EETA-79001; AMPHIBOLE; OXYGEN AB The Shergotty-Nakhla-Chassigny (SNC) meteorites, purportedly of martian origin, contain 0.04 to 0.4 percent water by weight. Oxygen isotopic analysis can bc used to determine whether this water is extraterrestrial or terrestrial. Such analysis reveals that a portion of the water is extraterrestrial and furthermore was not in oxygen isotopic equilibrium with the host rock. Lack of equilibrium between water and host rock implies that the lithosphere and hydrosphere of the SNC parent body formed two distinct oxygen isotopic reservoirs. If Mars was the parent body, the maintenance of two distinct reservoirs may result from the absence of plate tectonics on the planet. C1 NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,HOUSTON,TX 77058. UNIV CHICAGO,DEPT GEOPHYS SCI,CHICAGO,IL 60637. UNIV CHICAGO,ENRICO FERMI INST,DEPT CHEM,CHICAGO,IL 60637. NR 29 TC 129 Z9 130 U1 0 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 MAR 13 PY 1992 VL 255 IS 5050 BP 1409 EP 1411 DI 10.1126/science.11537889 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HH744 UT WOS:A1992HH74400046 PM 11537889 ER PT J AU HAZRA, R VILES, CL PARK, SK REICHENBACH, SE SIERACKI, ME AF HAZRA, R VILES, CL PARK, SK REICHENBACH, SE SIERACKI, ME TI MODEL-BASED FREQUENCY-RESPONSE CHARACTERIZATION OF A DIGITAL-IMAGE ANALYSIS SYSTEM FOR EPIFLUORESCENCE MICROSCOPY SO APPLIED OPTICS LA English DT Article ID CHARGE-COUPLED-DEVICE; DESIGN AB We describe a model-based method for estimating the spatial frequency response of a digital-imaging system (e.g., a CCD camera) that is modeled as a linear, shift-invariant image acquisition subsystem that is cascaded with a linear, shift-variant sampling subsystem. The method characterizes the two-dimensional frequency response of the image acquisition subsystem to beyond the Nyquist frequency by accounting explicitly for insufficient sampling and the sample-scene phase. Results for simulated systems and a real CCD-based epifluorescence microscopy system are presented to demonstrate the accuracy of the method. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. COLL WILLIAM & MARY,VIRGINIA INST MARINE SCI,WILLIAMSBURG,VA 23185. UNIV NEBRASKA,DEPT COMP SCI,LINCOLN,NE 68508. RP HAZRA, R (reprint author), COLL WILLIAM & MARY,DEPT COMP SCI,WILLIAMSBURG,VA 23185, USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAR 10 PY 1992 VL 31 IS 8 BP 1083 EP 1092 PG 10 WC Optics SC Optics GA HH126 UT WOS:A1992HH12600014 PM 20720725 ER PT J AU REICHERT, GA BRANDUARDIRAYMONT, G FILIPPENKO, AV MASON, KO PUCHNAREWICZ, EM WU, CC AF REICHERT, GA BRANDUARDIRAYMONT, G FILIPPENKO, AV MASON, KO PUCHNAREWICZ, EM WU, CC TI SPATIALLY RESOLVED ULTRAVIOLET SPECTROSCOPY OF THE LINER GALAXY NGC-3998 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC-3998); GALAXIES, NUCLEI; GALAXIES, STELLAR CONTENT; ULTRAVIOLET, SPECTRA ID X-RAY; GALACTIC NUCLEI; RADIO-SOURCES; S0 GALAXIES; COLOR DISTRIBUTIONS; PHYSICAL CONDITIONS; SURFACE BRIGHTNESS; VELOCITY-FIELD; E/S0 GALAXIES; EMISSION AB We report results of recent IUE observations of the low-ionization nuclear emission-line region (LINER) galaxy NGC 3998. Spatial structure in the long-wavelength emission is apparent; the spatial profiles in the LWP images show a two-component structure, with an unresolved central component superposed on extended underlying emission. We have used new software, which exploits knowledge of the LWP point spread function and its variation with wavelength, to model the spatial profiles and to separate the LWP emission into component spectra. The profiles can be modeled as the sums of unresolved (point source) components and extended Gaussians having intrinsic sigmas of approximately 4".5. The centers of the unresolved and extended components coincide to within 0".2. The unresolved component spectrum is considerably flatter than the spectrum of the extended component, which is dominated by fairly late-type stars (late F to early G). The unresolved component also shows strong C II] lambda-2326 and broad Mg II lambda-2800 emission. The width of the Mg II emission is approximately 8000 km s-1, and its profile agrees quite well with the broad wings of the H-alpha emission. The prominence of Mg II relative to C II] indicates that the broad-line emitting gas must be dense (n(e) greater than or similar to 10(9) cm-3). Finally, the spectrum of the unresolved component is also dominated by starlight, but allows a photoionizing power-law continuum of sufficient flux to account for the emission-line fluxes if the emission-line spectrum is similar to that seen in M81. These results strengthen the resemblance between NGC 3998 and M81, and further support the idea that NGC 3998 may contain a "dwarf" Seyfert nucleus. C1 NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. UCL, MULLARD SPACE SCI LAB, HOLMBURY ST MARY, SURREY, ENGLAND. UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. COMP SCI CORP, INST SPACE TELESCOPE SCI, BALTIMORE, MD 21218 USA. RP REICHERT, GA (reprint author), COMP SCI CORP, ASTRON PROGRAMS, BALTIMORE, MD 21218 USA. NR 70 TC 10 Z9 10 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1992 VL 387 IS 2 BP 536 EP 550 DI 10.1086/171105 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF938 UT WOS:A1992HF93800011 ER PT J AU DWEK, E FELTEN, JE AF DWEK, E FELTEN, JE TI LINE FLUORESCENCE FROM THE RING AROUND SUPERNOVA-1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, DISTANCES; GALAXIES, MAGELLANIC CLOUDS; STARS, CIRCUMSTELLAR SHELLS; STARS, INDIVIDUAL (SN-1987A); STARS, SUPERNOVAE ID SN-1987A; 1987A; CLOUD; ECHO AB We review observations in lambda-5007 which reveal an ellipse of line emission around SN 1987A. Spectroscopy suggests that it is an inclined ring of gas, presumably excited by the UV flash associated with shock breakout. The occurrence of this flash was confirmed earlier by IUE observations of narrow fluorescent lines from the SN. We derive a simple expression for the rate at which the kinematically accessible paraboloid sweeps over the length of a thin uniform circular ring, and present a simple integral expression for the light curve F(t) of a fluorescent line in terms of epsilon(t), the local line emissivity. Our resulting light curves agree well with computations by Lundqvist but not so well with those by Panagia and Gilmozzi. This, together with the variety of possible light curves and the uncertainties in the ring geometry and morphology, suggests that the claimed error bar (+/- 6%) on the distance determination by Panagia et al. should be treated with caution. We graph many simple examples of the relationship between epsilon(t) and F(t) and use the results to deduce the characteristics of the local emissivity functions which will produce the best fit to the observed N III] lambda-1750 and N V lambda-1240 light curves. Adopting physical models by Lundqvist and Fransson for an optically thin gas, in which the functions epsilon(t) for these lines peak only after recombination has occurred, we find poor agreement with the observed light curves for these lines. Better agreement is obtained if epsilon(t) responds quickly to the UV flash and persists approximately 300 days afterwards (suggesting that the ring may have been optically thick to the UV flash); a characteristic arcsine shape is then seen on the leading side of the light curve. The different shape of the N IV] lambda-1485 light curve remains a puzzle. We invert the N III and N V light curves to find the functions epsilon(t) which give best fits to the observations. The inversions are affected by scatter in the data. Nevertheless they give marginal evidence that an additional gas cloud is contributing to the UV line fluxes at t greater than or similar to 700 days. C1 NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. RP DWEK, E (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, INFRARED ASTROPHYS BRANCH, CODE 685, GREENBELT, MD 20771 USA. NR 43 TC 22 Z9 22 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1992 VL 387 IS 2 BP 551 EP 560 DI 10.1086/171106 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF938 UT WOS:A1992HF93800012 ER PT J AU REAMES, DV RICHARDSON, IG WENZEL, KP AF REAMES, DV RICHARDSON, IG WENZEL, KP TI ENERGY-SPECTRA OF IONS FROM IMPULSIVE SOLAR-FLARES SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, FLARES; SUN, PARTICLE EMISSION; SUN, X-RAYS, GAMMA-RAYS ID HE-3-RICH EVENTS; PARTICLE EVENTS; ELECTRON EVENTS; ACCELERATION AB We report on a study of the energy spectra of ions from impulsive solar flares in the 0.1-100 MeV region obtained from the combined observations of three experiments on the ISEE 3 and IMP 8 spacecraft. Most of the events studied are dominated by He and these He spectra show a persistent steepening or break above approximately 10 MeV resulting in an increase in the power-law spectral indices from approximately 2 to approximately 3.5 or more. Spectra of H, He-3, He-3, O and Fe have spectral indices that are consistent with a value of approximately 3.5 above approximately 2 MeV amu-1. One event, dominated by protons, shows a clear maximum in the spectrum near 1 MeV. If the roll-over in the spectrum below 1 MeV is interpreted as a consequence of matter traversal in the solar atmosphere, then the source of the acceleration would lie only approximately 800 km above the photosphere, well below the corona. Alternative interpretations are that trapping in the acceleration region directly causes a peak in the resulting ion spectrum or that low-energy particles encounter significant additional scattering during transport from the flare. In two of the events, the normal velocity dispersion in the arrival of the ions is modulated by the passage of spatial structures in the interplanetary plasma. One of these events was previously interpreted as a " channel " of continuous particle emission from the Sun; we find no evidence for this interpretation. C1 EUROPEAN SPACE AGCY,EUROPEAN SPACE RES & TECHNOL CTR,DEPT SPACE SCI,2200 AG NOORDWIJK,NETHERLANDS. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. RP REAMES, DV (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 661,GREENBELT,MD 20771, USA. OI Richardson, Ian/0000-0002-3855-3634 NR 24 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 MAR 10 PY 1992 VL 387 IS 2 BP 715 EP 725 DI 10.1086/171120 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF938 UT WOS:A1992HF93800026 ER PT J AU GEBALLE, TR TIELENS, AGGM KWOK, S HRIVNAK, BJ AF GEBALLE, TR TIELENS, AGGM KWOK, S HRIVNAK, BJ TI UNUSUAL 3 MICRON EMISSION FEATURES IN 3 PROTO PLANETARY-NEBULAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, GENERAL; PLANETARY NEBULAE, GENERAL; STARS, EVOLUTION; CIRCUMSTELLAR MATTER ID POLYCYCLIC AROMATIC-HYDROCARBONS; INFRARED-SPECTRA; IRAS SOURCES; SPECTROSCOPY; DUST; STAR AB Medium-resolution 3-4-mu-m spectra have been obtained of three objects, IRAS 04296 + 3429, IRAS 22272 + 5435, and CRL 2688, which are in transition between the asymptotic red giant branch and the planetary nebula phase. All three show unusual 3-mu-m emission features. The two IRAS objects, already unusual in having 21-mu-m features, have remarkably strong 3.4-3.5-mu-m emission relative to the usually dominant 3.3-mu-m feature, with the spectrum of IRAS 04296 + 3429 being nearly identical to that of IRAS 05341 + 0852 (previously published). CRL 2688's spectrum bears some resemblance to those of the IRAS objects, but its 3.4-3.5-mu-m emission is not as strong. The relationships between the various emission features are discussed. CRL 2688 may be completing a transition between the "21-mu-m phase" and the "normal phase," which is associated with dominant 3.3-mu-m emission, weak 3.4-3.6-mu-m features and plateau, and a lack of 21-mu-m emission. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV CALGARY, DEPT PHYS & ASTRON, CALGARY T2N 1N4, ALBERTA, CANADA. VALPARAISO UNIV, DEPT PHYS, VALPARAISO, IN 46383 USA. RP GEBALLE, TR (reprint author), JOINT ASTRON CTR, 665 KOMOHANA ST, HILO, HI 96720 USA. RI Kwok, Sun/D-3080-2009 OI Kwok, Sun/0000-0001-7708-081X NR 25 TC 72 Z9 72 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1992 VL 387 IS 2 BP L89 EP L91 DI 10.1086/186312 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF939 UT WOS:A1992HF93900009 ER PT J AU YAMASHITA, T TAMURA, M AF YAMASHITA, T TAMURA, M TI THE MOLECULAR-HYDROGEN EMISSION AROUND L1551 IRS-5 - SHOCK-HEATED MOLECULAR GAS AT THE BASE OF THE MOLECULAR OUTFLOW SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, INTERSTELLAR, LINES; ISM, INDIVIDUAL OBJECTS, L1551 IRS-5; ISM, MOLECULES; SHOCK WAVES; STARS, FORMATION ID T-TAURI STARS; OPTICAL SPECTROSCOPY; OBJECTS; CLOUDS; DISKS; WINDS; H2; CO AB We present spatially resolved observations of the v = 1-0 S(1) molecular hydrogen emission toward L1551 IRS 5 using the grating spectrometer at KPNO. The S(1) emission consists of a ridge component extending toward west along the optical jet from its peak on IRS 5 and a diffuse component which traces the innermost region of the cavity enclosed by the molecular outflow. The ridge component represents shock-heated molecular gas at the root of the optical jet. The diffuse component is too bright to be of scattered origin; it most likely arises from shock-heated gas within the cavity and could represent an acceleration process of the molecular outflow. C1 UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP YAMASHITA, T (reprint author), NATL ASTRON OBSERV,MITAKA,TOKYO 181,JAPAN. NR 25 TC 9 Z9 9 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 1992 VL 387 IS 2 BP L93 EP L96 DI 10.1086/186313 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF939 UT WOS:A1992HF93900010 ER PT J AU GENRICH, JF BOCK, Y AF GENRICH, JF BOCK, Y TI RAPID RESOLUTION OF CRUSTAL MOTION AT SHORT RANGES WITH THE GLOBAL POSITIONING SYSTEM SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SAN-ANDREAS-FAULT; CENTRAL CALIFORNIA; DEFORMATION; PARKFIELD; SLIP AB On the basis of the analysis of Global Positioning System (GPS) data collected at the U.S. Geological Survey Kennedy Ranch House alinement array near Parkfield, California, in November 1990 and February 1991, we assess the temporal resolution of crustal deformation for GPS receiver systems operating as strain meters and provide guidelines for achieving millimeter-level precision with short-range, kinematic-type GPS measurements. Site occupation of about one-half hour is sufficient for day-to-day repeatability of submillimeter precision in relative position during good satellite geometry. Signal multipath effects which dominate dispersive baseline errors are essentially averaged out and need not be modeled. However, as occupation times decrease, baseline solutions are increasingly sensitive to multipath effects which together with nondispersive receiver measurement noise, are of millimeter to centimeter magnitude in epoch-by-epoch solutions. On repeatedly monitored baselines we can account for both of these noise sources separately. The mostly random receiver noise is effectively suppressed by low-pass filters with corner frequencies of about 20 mHz. The multipath noise is filtered using the fact that it essentially repeats from day to day. Residual errors in filtered 1-s epoch-by-epoch solutions are below 2 mm during periods of good satellite geometry. Hence for a continuously monitored baseline, actual deformation in excess of this threshold can be detected with a time lag comparable to the group delay of the low-pass filter, i.e., typically within a minute. In terms of strain along a typical short baseline of 1 km sampled once per second we can detect 1-2-mu-s in 1 min with multipath modeling. Without multipath modeling, it takes 10 min to resolve the same magnitude of deformation. In 30 min we can detect 0.1-mu-s independent of multipath modeling. These results have important implications for kinematic-type GFS surveys. For millimeter-level precision without impractical multipath modeling it is necessary to occupy a site during good satellite geometry for a period longer than that of the multipath signature. Our experience in both benign and difficult multipath environments indicates that approximately 10 min are sufficient. The measurements at the Kennedy Ranch House alinement array suggest that this segment of the San Andreas fault appears to be virtually locked at the surface during the 3-month period between the two surveys. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP GENRICH, JF (reprint author), UNIV CALIF SAN DIEGO,SCRIPPS INST OCEANOG,INST GEOPHYS & PLANETARY PHYS,0225,LA JOLLA,CA 92093, USA. NR 21 TC 65 Z9 70 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-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 10 PY 1992 VL 97 IS B3 BP 3261 EP 3269 DI 10.1029/91JB02997 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HG748 UT WOS:A1992HG74800003 ER PT J AU YAMAMOTO, Y MACHIDA, S RICHARDSON, WH AF YAMAMOTO, Y MACHIDA, S RICHARDSON, WH TI PHOTON NUMBER SQUEEZED STATES IN SEMICONDUCTOR-LASERS SO SCIENCE LA English DT Article ID NOISE; LIGHT; UNCERTAINTY; INTERFEROMETER; SUPPRESSION; OSCILLATOR AB Electromagnetic fields, with the noise on one quadrature component reduced to below the quantum mechanical zero-point fluctuation level and the noise on the other quadrature component enhanced to above it, are currently of great interest in quantum optics because of their potential applications to various precision measurements. Such squeezed states of light are usually produced by imposing nonlinear unitary evolution on coherent (or vacuum) states. On the other hand, squeezed states with reduced photon number noise and enhanced phase noise are generated directly by a constant current - driven semiconductor laser. This is the simplest scheme for the generation of nonclassical light, and so far it has yielded the largest quantum noise reduction. The mutual coupling between a lasing junction and an external electrical circuit provides opportunities for exploring the macroscopic and microscopic quantum effects in open systems. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP YAMAMOTO, Y (reprint author), NIPPON TELEGRAPH & TEL PUBL CORP, MUSASHINO ELECT COMMUN LAB, BASIC RES LABS, MUSASHINO, TOKYO 180, JAPAN. RI Yamamoto, Yoshihisa/A-2811-2012 NR 43 TC 32 Z9 35 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAR 6 PY 1992 VL 255 IS 5049 BP 1219 EP 1224 DI 10.1126/science.255.5049.1219 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HG677 UT WOS:A1992HG67700032 PM 17816827 ER PT J AU SODUPE, M BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H AF SODUPE, M BAUSCHLICHER, CW LANGHOFF, SR PARTRIDGE, H TI THEORETICAL-STUDY OF THE BONDING OF THE 1ST-ROW TRANSITION-METAL POSITIVE-IONS TO ETHYLENE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; GAS-PHASE; ELECTRON CORRELATION; SCANDIUM IONS; GROUND-STATE; C-H; ATOMS; ETHANE; ENERGIES; ORBITALS AB Ab initio calculations have been performed to study the bonding of the first-row transition-metal ions with ethylene. While Sc+ and Ti+ insert into the pi-bond of ethylene to form a three-membered ring, the ions V+ through Cu+ form an electrostatic complex with ethylene. The binding energies are compared with those from experiment and with those of comparable calculations performed previously for the metal-acetylene ion systems. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 42 TC 130 Z9 130 U1 2 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD MAR 5 PY 1992 VL 96 IS 5 BP 2118 EP 2122 DI 10.1021/j100184a020 PG 5 WC Chemistry, Physical SC Chemistry GA HG753 UT WOS:A1992HG75300020 ER PT J AU PADULA, SL SANDRIDGE, CA WALSH, JL HAFTKA, RT AF PADULA, SL SANDRIDGE, CA WALSH, JL HAFTKA, RT TI INTEGRATED CONTROLS STRUCTURES OPTIMIZATION OF A LARGE SPACE STRUCTURE SO COMPUTERS & STRUCTURES LA English DT Article ID FLEXIBLE SPACECRAFT; DESIGN AB The next generation of large space structure (LSS) will undoubtedly be characterized by high flexibility and low inherent damping and will benefit from integrated controls-structures (C-S) optimization. New methods are required to optimize these LSS for low weight and low power consumption while meeting operational and safety requirements. There is great interest in C-S optimization, but most research has focused on problems with simple models and simplified constraints implemented using special purpose software. The present research is significant because it uses general purpose control and structural analysis codes, is applied to a large, detailed structural model and includes objective and constraint functions derived from actual design specifications. Structural design variables are truss member sizes, material properties and spacecraft dimensions. Control design variables are gains. The approach is to divide the problem into a structural optimization step, a controls optimization step and a system level coordination step. The objective is to minimize mass and power consumption with constraints on strength, vibration characteristics and damping. This decomposition and optimization approach significantly improves the design of a structure based on the COFS-I Mast Flight System, which is chosen as a demonstration problem. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT AEROSP & OCEAN ENGN,BLACKSBURG,VA 24061. RP PADULA, SL (reprint author), NASA,LANGLEY RES CTR,MS 246,HAMPTON,VA 23665, USA. NR 25 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD MAR 3 PY 1992 VL 42 IS 5 BP 725 EP 732 DI 10.1016/0045-7949(92)90184-2 PG 8 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA HJ466 UT WOS:A1992HJ46600006 ER PT J AU CROOKER, NU CLIVER, EW TSURUTANI, BT AF CROOKER, NU CLIVER, EW TSURUTANI, BT TI THE SEMIANNUAL VARIATION OF GREAT GEOMAGNETIC STORMS AND THE POSTSHOCK RUSSELL-MCPHERRON EFFECT PRECEDING CORONAL MASS EJECTA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC-FIELD; DAYSIDE MAGNETOPAUSE AB The occurrence rate of great geomagnetic storms displays a pronounced semiannual variation. Of the forty-two great storms during the period 1940-1990, none occurred during the solstitial months of June and December, and 40% (17) occurred during the equinoctial months of March and September. This suggests that the semiannual variation found by averaging indices is not the result of some statistical effect superposed on the effects of random storm occurrence but rather is dominated by the storms themselves. Recent results indicate that the intense southward interplanetary magnetic fields (IMFs) responsible for great storms can reside in the postshock plasma preceding the driver gas of coronal mass ejections (CMEs) as well as in the driver gas itself. Here we propose that strong southward fields in the postshock flow result from a major increase in the Russell-McPherron polarity effect through a systematic pattern of compression and draping within the ecliptic plane. Differential compression at the shock increases the Parker spiral angle and, consequently, the azimuthal field component that projects as a southward component onto Earth's dipole axis. The resulting prediction is that southward fields in the postshock plasma maximize at the spring (fall) equinox in CMEs emerging from toward (away) sectors. This pattern produces a strong semiannual variation in postshock IMF orientation and may account at least in part for the observed semiannual variation of the occurrence of great geomagnetic storms. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP CROOKER, NU (reprint author), PHILLIPS LAB,GPSG,GEOPHYS DIRECTORATE,BEDFORD,MA 01731, USA. NR 24 TC 54 Z9 55 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 MAR 3 PY 1992 VL 19 IS 5 BP 429 EP 432 DI 10.1029/92GL00377 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HH091 UT WOS:A1992HH09100001 ER PT J AU FELDMAN, PD DAVIDSEN, AF BLAIR, WP BOWERS, CW DURRANCE, ST KRISS, GA FERGUSON, HC KIMBLE, RA LONG, KS AF FELDMAN, PD DAVIDSEN, AF BLAIR, WP BOWERS, CW DURRANCE, ST KRISS, GA FERGUSON, HC KIMBLE, RA LONG, KS TI THE SPECTRUM OF THE TROPICAL OXYGEN NIGHTGLOW OBSERVED AT 3A RESOLUTION WITH THE HOPKINS ULTRAVIOLET TELESCOPE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ION-ION NEUTRALIZATION; RECOMBINATION; AIRGLOW AB Ultraviolet spectra of the tropical oxygen nightglow in the range of 830 to 1850 angstrom (in first order) at 3 angstrom resolution were obtained with the Hopkins Ultraviolet Telescope during the Astro-1 space shuttle mission in December 1990. We present here the data obtained on a setting celestial target as the zenith angle of the line-of-sight varied from 77 to 95-degrees. The dominant features in the spectrum (other than geocoronal hydrogen) are O I-lambda-lambda-1304 and 1356 and the radiative recombination continuum near 911 angstrom. The continuum is resolved and found to be consistent with an electron temperature in the range 1000-1250 K. The observed ratio of the brightness of O I-lambda-1356 to the continuum suggests that O+ - O- mutual neutralization contributes about 40% to the 1356 angstrom emission. The dependence of the optically thin emissions on zenith angle is consistent with a simple ionospheric model. Weak O I-lambda-989 emission is also detected, but there is no evidence for any similarly produced atomic nitrogen emissions. C1 UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP FELDMAN, PD (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. RI Kimble, Randy/D-5317-2012 NR 16 TC 38 Z9 38 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 3 PY 1992 VL 19 IS 5 BP 453 EP 456 DI 10.1029/92GL00376 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HH091 UT WOS:A1992HH09100007 ER PT J AU OHSAKA, K TRINH, EH HOLZER, JC JOHNSON, WL AF OHSAKA, K TRINH, EH HOLZER, JC JOHNSON, WL TI GIBBS FREE-ENERGY DIFFERENCE BETWEEN THE UNDERCOOLED LIQUID AND THE BETA-PHASE OF A TI-CR ALLOY SO APPLIED PHYSICS LETTERS LA English DT Article ID SPONTANEOUS VITRIFICATION; AMORPHIZATION AB The heat of fusion and the specific heats of the solid and liquid have been experimentally determined for a Ti60Cr40 alloy. The data are used to evaluate the Gibbs free energy difference, DELTA-G, between the liquid and the beta-phase as a function of temperature to verify a reported spontaneous vitrification (SV) of the beta-phase in Ti-Cr alloys. The results show that SV of an undistorted beta-phase in the Ti60Cr40 alloy at 873 K is not feasible because DELTA-G is positive at the temperature. However, DELTA-G may become negative with additional excess free energy to the beta-phase in the form of defects. C1 CALTECH,WM KECK LAB ENGN MAT,PASADENA,CA 91125. RP OHSAKA, K (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 16 TC 17 Z9 17 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 2 PY 1992 VL 60 IS 9 BP 1079 EP 1081 DI 10.1063/1.106450 PG 3 WC Physics, Applied SC Physics GA HF856 UT WOS:A1992HF85600015 ER PT J AU KLEIN, MJ GULKIS, S WILCK, HC OLSEN, ET GARYANTES, MF BURNS, DJ ASMAR, PR BRADY, RB DEICH, WTS RENZETTI, NA AF KLEIN, MJ GULKIS, S WILCK, HC OLSEN, ET GARYANTES, MF BURNS, DJ ASMAR, PR BRADY, RB DEICH, WTS RENZETTI, NA TI STATUS OF THE NASA SETI SKY SURVEY MICROWAVE OBSERVING PROJECT SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 40TH CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-13, 1989 CL MALAGA, SPAIN SP INT ASTRONAUT FEDERAT AB The Sky Survey observing program is one of two complementary strategies that NASA plans to use in its microwave Search for Extraterrestrial Intelligence (SETI). The primary objective of the Sky Survey is to search the entire sky over the frequency range 1000-10,000 MHz for evidence of narrow band signals of extraterrestrial, intelligent origin. Spectrum analyzers with upwards of 10 million channels and data rates in excess of 10 gigabits per second are required to complete the survey in less than 7 years. To lay the foundation for the operational SETI Sky Survey, a prototype system has been built to test and refine real time signal detection algorithms, to test scan strategies and observatory control functions, and to test algorithms designed to reject radio frequency interference. This paper presents a high level description of the prototype hardware and software and reports on the preparations to deploy the system to the 34-m antenna at the research and development station of NASA's Deep Space Communication Complex, Goldstone, California. RP KLEIN, MJ (reprint author), JET PROP LAB,PASADENA,CA 91109, 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. PD MAR-APR PY 1992 VL 26 IS 3-4 BP 177 EP 184 DI 10.1016/0094-5765(92)90092-W PG 8 WC Engineering, Aerospace SC Engineering GA JF917 UT WOS:A1992JF91700010 PM 11537160 ER PT J AU BILLINGHAM, J TARTER, J AF BILLINGHAM, J TARTER, J TI DETECTION OF THE EARTH WITH THE SETI MICROWAVE OBSERVING SYSTEM ASSUMED TO BE OPERATING OUT IN THE GALAXY SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 40TH CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-13, 1989 CL MALAGA, SPAIN SP INT ASTRONAUT FEDERAT AB This paper estimates the maximum range at which radar signals from the Earth could be detected by a search system similar to the NASA Search for Extraterrestrial Intelligence Microwave Observing Project (SET] MOP) assumed to be operating out in the galaxy. Figures are calculated for the Targeted Search, and for the Sky Survey parts of the MOP, both operating, as currently planned, in the second half of the decade of the 1990s. Only the most powerful terrestrial transmitters are considered, namely, the planetary radar at Arecibo in Puerto Rico, and the ballistic missile early warning systems (BMEWS). In each case the probabilities of detection over the life of the MOP are also calculated. The calculation assumes that we are only in the eavesdropping mode. Transmissions intended to be detected by SETI systems are likely to be much stronger and would of course be found with higher probability to a greater range. Also, it is assumed that the transmitting civilization is at the same level of technological evolution as ours on Earth. This is very improbable. If we were to detect another technological civilization, it would, on statistical grounds, be much older than we are and might well have much more powerful transmitters. Both factors would make detection by the NASA MOP a much more likely outcome. RP BILLINGHAM, J (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 4 Z9 4 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. PD MAR-APR PY 1992 VL 26 IS 3-4 BP 185 EP 188 DI 10.1016/0094-5765(92)90093-X PG 4 WC Engineering, Aerospace SC Engineering GA JF917 UT WOS:A1992JF91700011 PM 11537161 ER PT J AU DREHER, JW AF DREHER, JW TI REJECTION OF RFI BY MEANS OF INTERFEROMETRY SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 40TH CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-13, 1989 CL MALAGA, SPAIN SP INT ASTRONAUT FEDERAT AB Preliminary results of a study of the feasability of using radio interferometry to reduce the RF levels encountered in the NASA Targeted Search SETI program are reported. RP DREHER, JW (reprint author), NASA,AMES RES CTR,SEARCH EXTRATERRESTRIAL INTELLIGENCE PROGRAM OFF,MOFFETT FIELD,CA 94035, 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 MAR-APR PY 1992 VL 26 IS 3-4 BP 223 EP 226 DI 10.1016/0094-5765(92)90101-N PG 4 WC Engineering, Aerospace SC Engineering GA JF917 UT WOS:A1992JF91700019 ER PT J AU KLEIN, MJ GULKIS, S OLSEN, ET ARMSTRONG, EF JACKSON, EB AF KLEIN, MJ GULKIS, S OLSEN, ET ARMSTRONG, EF JACKSON, EB TI AN ASSESSMENT OF THE IMPACT OF RADIOFREQUENCY INTERFERENCE ON MICROWAVE SETI SEARCHES SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 40TH CONGRESS OF THE INTERNATIONAL ASTRONAUTICAL FEDERATION CY OCT 07-13, 1989 CL MALAGA, SPAIN SP INT ASTRONAUT FEDERAT AB Investigations are carried out at JPL on radiofrequency interferences at very low levels (- 130 to - 180 dBm) in various bands, especially the 1-2 GHz band. Extrapolation of interferences in the years to come is attempted. RP KLEIN, MJ (reprint author), JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAR-APR PY 1992 VL 26 IS 3-4 BP 227 EP 232 DI 10.1016/0094-5765(92)90102-O PG 6 WC Engineering, Aerospace SC Engineering GA JF917 UT WOS:A1992JF91700020 PM 11537163 ER PT J AU EIKEN, O CONVERTINO, VA DOERR, DF DUDLEY, GA MORARIU, G MEKJAVIC, IB AF EIKEN, O CONVERTINO, VA DOERR, DF DUDLEY, GA MORARIU, G MEKJAVIC, IB TI CHARACTERISTICS OF THE CAROTID BAROREFLEX IN MAN DURING NORMAL AND FLOW-RESTRICTED EXERCISE SO ACTA PHYSIOLOGICA SCANDINAVICA LA English DT Article DE ARTERIAL BAROREFLEX PRESSURE-RESPONSE RELATION; ISCHEMIC EXERCISE ID BARORECEPTOR-CARDIAC REFLEX; AORTIC BARORECEPTORS; BLOOD-PRESSURE; HUMANS; RESPONSES AB Eight subjects were studied in the supine position at rest, during normal dynamic leg exercise (control exercise) and with blood-flow restriction in the working legs (flow-restricted exercise). Graded muscle blood-flow restriction was accomplished by applying a supra-atmospheric pressure of 50 mmHg to the working legs. During incremental-load exercise, flow restriction reduced exercise performance and peak heart rate by 36% and 13%, respectively. The function of the cardiac branch of the carotid baroreflex was studied over its full operational range, at rest and during constant-load control and flow-restricted exercise, by measuring R-R intervals during application of pulse-synchronous graded pressures (40 to -65 mmHg) in a neck-chamber device. Heart rate and arterial pressure were higher during flow-restricted than control exercise, indicating that the flow restriction activated the muscle chemoreflex. Raising the carotid transmural pressure (systolic arterial pressure minus neck-chamber pressure) was accompanied by increasing R-R intervals in all conditions. The set point (point of baseline carotid transmural pressure and R-R interval) coincided with the midportion of the pressure-response curve at rest and with the threshold point of the curve during exercise. The maximal rate of change in relative R-R intervals and the corresponding carotid transmural pressure range were higher during control exercise than at rest and highest during flow-restricted exercise, indicating that exercise and especially flow-restricted exercise increased carotid baroflex sensitivity, and shifted the carotid baroreflex optimal buffering range to higher pressures. The results suggest that the carotid baroflex attenuates exercise heart rate increases mediated by the muscle chemoreflex and/or by central command. C1 SIMON FRASER UNIV,SCH KINESIOL,BURNABY V5A 1S6,BC,CANADA. NASA,BIOMED OPERAT & RES OFF,KENNEDY SPACE CTR,FL. BIONET CORP,KENNEDY SPACE CTR,FL. NR 29 TC 33 Z9 33 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0001-6772 J9 ACTA PHYSIOL SCAND JI Acta Physiol. Scand. PD MAR PY 1992 VL 144 IS 3 BP 325 EP 331 DI 10.1111/j.1748-1716.1992.tb09301.x PG 7 WC Physiology SC Physiology GA HH135 UT WOS:A1992HH13500013 PM 1585815 ER PT J AU GEE, K CUMMINGS, RM SCHIFF, LB AF GEE, K CUMMINGS, RM SCHIFF, LB TI TURBULENCE MODEL EFFECTS ON SEPARATED FLOW ABOUT A PROLATE SPHEROID SO AIAA JOURNAL LA English DT Article ID DIFFERENCE AB The three-dimensional separated flow about a prolate spheroid at high incidence is numerically investigated using the F3D thin-layer Navier-Stokes code. The effect of different turbulence models on the flowfield solution and the characteristics of the predicted flow are analyzed. The models used in this study are the Baldwin-Lomax algebraic model, the Baldwin-Lomax model as modified for crossflow separation by Degani and Schiff, and a modified version of the Johnson-King model with and without the Degani-Schiff crossflow modifications applied. The Johnson-King model is applied to assess the importance of modeling nonequilibrium effects in predicting flow about a slender body at high incidence. The computations are made for steady-state, fully turbulent flow. The results are compared with experimental pressure data and with computational results obtained by Panaras and Steger, using the identical code and grid, but with their own modifications to the Baldwin-Lomax model. In addition, the computed solutions are analyzed using surface flow patterns, helicity density contours, and turbulent eddy-viscosity profiles. The results of this analysis provide insight into the effects of the turbulence models on flow characteristics and demonstrate the effect of the models on the accurate prediction of highly separated and vortical flows about a slender body. C1 CALIF POLYTECH STATE UNIV SAN LUIS OBISPO,DEPT AERONAUT ENGN,SAN LUIS OBISPO,CA 93407. NASA,AMES RES CTR,DIV FLUID DYNAM,MOFFETT FIELD,CA 94035. RP GEE, K (reprint author), NASA,AMES RES CTR,MCAT INST,MS 258-1,MOFFETT FIELD,CA 94035, USA. NR 31 TC 18 Z9 19 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1992 VL 30 IS 3 BP 655 EP 664 DI 10.2514/3.10969 PG 10 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800011 ER PT J AU MAESTRELLO, L GROSVELD, FW AF MAESTRELLO, L GROSVELD, FW TI TRANSITION CONTROL OF INSTABILITY WAVES OVER AN ACOUSTICALLY EXCITED FLEXIBLE SURFACE SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 13TH AEROACOUSTICS CONF CY OCT 22-24, 1990 CL TALLAHASSEE, FL SP AMER INST AERONAUT & ASTRONAUT ID TOLLMIEN-SCHLICHTING WAVES; BOUNDARY-LAYER; ACTIVE CONTROL; EXCITATION AB Experimental results are presented that demonstrate the coupling of a laminar boundary-layer flow with a typical flexible aircraft panel. It is shown that the boundary layer induces plate oscillations that, in turn, perturb the flow at the same frequencies. This feedback mechanism is an inherent property of laminar boundary-layer flow passing over a flexible plate. As a result, the flexibility of the plate becomes a source of early transition. The laminar boundary layer at the leading edge of the plate reacts to small unsteady disturbances from upstream due to a streamwise pressure gradient. The experiments demonstrate that a nominal sound pressure incident at the leading edge triggers early transition. It is shown that this transition can be delayed by activating a heat source at the leading edge of the plate, which results in downstream cooling. C1 LOCKHEED ENGN & SCI CO,LANGLEY PROGRAM OFF,HAMPTON,VA 23666. RP MAESTRELLO, L (reprint author), NASA,LANGLEY RES CTR,DIV ACOUST,STRUCT ACOUST BRANCH,41 MAIL STOP 463,HAMPTON,VA 23665, USA. NR 40 TC 5 Z9 5 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 1992 VL 30 IS 3 BP 665 EP 670 DI 10.2514/3.10970 PG 6 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800012 ER PT J AU ARYA, VK ARNOLD, SM AF ARYA, VK ARNOLD, SM TI VISCOPLASTIC ANALYSIS OF AN EXPERIMENTAL CYLINDRICAL THRUST CHAMBER LINER SO AIAA JOURNAL LA English DT Article AB A viscoplastic stress-strain analysis of an experimental cylindrical thrust chamber is presented. A viscoplastic constitutive model incorporating a single internal state variable that represents kinematic hardening was employed to investigate whether such a viscoplastic model could predict the experimentally observed behavior of the thrust chamber. Two types of loading cycles were considered: a short cycle of 3.5-s duration that corresponded to the experiments and an extended loading cycle of 485.1-s duration that is typical of the Space Shuttle Main Engine (SSME) operating cycle. The analysis qualitatively replicated the deformation behavior of the component as observed in experiments at NASA Lewis Research Center. These experiments were designed to simulate the SSME operating conditions. The analysis also showed that the mode and location of failure in the component may depend on the loading cycle. The results indicate that using viscoplastic models for structural analysis can lead to a more realistic life assessment of thrust chambers. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP ARYA, VK (reprint author), UNIV TOLEDO,TOLEDO,OH 43606, USA. NR 17 TC 16 Z9 18 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 MAR PY 1992 VL 30 IS 3 BP 781 EP 789 DI 10.2514/3.10985 PG 9 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800027 ER PT J AU SARAVANOS, DA CHAMIS, CC AF SARAVANOS, DA CHAMIS, CC TI MULTIOBJECTIVE SHAPE AND MATERIAL OPTIMIZATION OF COMPOSITE STRUCTURES INCLUDING DAMPING SO AIAA JOURNAL LA English DT Article ID OPTIMUM DESIGN; FIBER ORIENTATION; STIFFNESS; LAMINATE; PLATES AB A multiobjective optimal design methodology is developed for lightweight, low-cost composite structures of improved dynamic performance. The design objectives may include minimization of damped resonance amplitudes (or maximization of modal damping), weight, and material cost. The design vector includes micromechanics, laminate, and structural shape parameters. Constraints are imposed on static displacements, static and dynamic ply stresses, dynamic amplitudes, and natural frequencies. The effects of composite damping tailoring on the dynamics of the composite structure are incorporated. Applications on a cantilever composite beam and plate illustrate that only the proposed multiobjective formulation, as opposed to single objective functions, may simultaneously improve the objectives. The significance of composite damping in the design of advanced composite structures is also demonstrated, and the results indicate that the minimum-weight design or design methods based on undamped dynamics may fail to improve the dynamic performance near resonances. RP SARAVANOS, DA (reprint author), NASA,LEWIS RES CTR,DIV STRUCT,21000 BROKPK RD,MAIL STOP 49-8,CLEVELAND,OH 44135, USA. NR 23 TC 34 Z9 35 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 MAR PY 1992 VL 30 IS 3 BP 805 EP 813 DI 10.2514/3.10988 PG 9 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800030 ER PT J AU HAFTKA, RT WALSH, JL AF HAFTKA, RT WALSH, JL TI STACKING-SEQUENCE OPTIMIZATION FOR BUCKLING OF LAMINATED PLATES BY INTEGER PROGRAMMING SO AIAA JOURNAL LA English DT Article ID COMPOSITE PLATES; OPTIMUM DESIGN; COMPRESSION AB Integer-programming formulations for the design of symmetric and balanced laminated plates under biaxial compression are presented. Both maximization of buckling load for a given total thickness and the minimization of total thickness subject to a buckling constraint are formulated. The design variables that define the stacking sequence of the laminate are zero-one integers. It is shown that the formulation results in a linear optimization problem that can be solved on readily available software. This is in contrast to the continuous case, where the design variables are the thicknesses of layers with specified ply orientations, and the optimization problem is nonlinear. Constraints on the stacking sequence such as a limit on the number of contiguous plies of the same orientation and limits on in-plane stiffnesses are easily accommodated. Examples are presented for graphite-epoxy plates under uniaxial and biaxial compression using a commercial software package based on the branch-and-bound algorithm. C1 NASA,LANGLEY RES CTR,INTERDISCIPLINARY RES OFF,HAMPTON,VA 23665. RP HAFTKA, RT (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT AEROSP & OCEAN ENGN,BLACKSBURG,VA 24061, USA. NR 16 TC 63 Z9 72 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 MAR PY 1992 VL 30 IS 3 BP 814 EP 819 DI 10.2514/3.10989 PG 6 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800031 ER PT J AU BELL, JH PLESNIAK, MW MEHTA, RD AF BELL, JH PLESNIAK, MW MEHTA, RD TI SPANWISE AVERAGING OF PLANE MIXING LAYER PROPERTIES SO AIAA JOURNAL LA English DT Note C1 STANFORD UNIV,DEPT MECH ENGN,DIV THERMOSCI,STANFORD,CA 94305. STANFORD UNIV,JOINT INST AERONAUT & ASTRONAUT,DEPT AERONAUT & ASTRONAUT,STANFORD,CA 94305. RP BELL, JH (reprint author), NASA,AMES RES CTR,FLUID DYNAM RES BRANCH,MAIL STOP 260-1,MOFFETT FIELD,CA 94035, USA. OI Plesniak, Michael/0000-0001-6575-5074 NR 4 TC 13 Z9 13 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 MAR PY 1992 VL 30 IS 3 BP 835 EP 837 DI 10.2514/3.10992 PG 3 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800034 ER PT J AU DEGANI, D AF DEGANI, D TI NUMERICAL-SIMULATION OF VORTEX UNSTEADINESS ON A SLENDER BODY AT HIGH-INCIDENCE SO AIAA JOURNAL LA English DT Note ID CYLINDER; TRANSITION; WAKE RP DEGANI, D (reprint author), NASA,AMES RES CTR,FAC MECH ENGN,MOFFETT FIELD,CA 94035, USA. NR 12 TC 2 Z9 2 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 MAR PY 1992 VL 30 IS 3 BP 841 EP 843 DI 10.2514/3.10995 PG 3 WC Engineering, Aerospace SC Engineering GA HJ908 UT WOS:A1992HJ90800037 ER PT J AU WOODGATE, BE AF WOODGATE, BE TI SPECTROSCOPY FROM THE HUBBLE SPACE TELESCOPE - KEYNOTE LECTURE SO ANALYST LA English DT Article; Proceedings Paper CT 27TH INTERNATIONAL COLLOQUIUM ON SPECTROSCOPY CY JUN, 1991 CL NORWAY DE HUBBLE; SPACE; ULTRAVIOLET; SPECTRA; ASTRONOMY AB Early spectroscopic results from the Goddard High Resolution Spectrograph and the Faint Object Spectrograph on the Hubble Space Telescope (HST) are described, including detection of intergalactic material between the Earth and a quasi-stellar object, observations of a chemically unusual star with large overabundances of heavy metals and material surrounding a nearby star. Planned improvements to the HST by in-orbit interchange include correction for the spherical aberration and the provision of more capable instruments. RP WOODGATE, BE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. RI Woodgate, Bruce/D-2970-2012 NR 13 TC 0 Z9 0 U1 1 U2 1 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0003-2654 J9 ANALYST JI Analyst PD MAR PY 1992 VL 117 IS 3 BP 239 EP 241 DI 10.1039/an9921700239 PG 3 WC Chemistry, Analytical SC Chemistry GA HM863 UT WOS:A1992HM86300006 ER PT J AU ROHATGI, NK INGHAM, JD AF ROHATGI, NK INGHAM, JD TI CONVERSION OF BIOPROCESS ETHANOL TO INDUSTRIAL-CHEMICAL PRODUCTS - APPLICATIONS OF PROCESS MODELS FOR ENERGY-ECONOMIC ASSESSMENTS SO APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY LA English DT Article; Proceedings Paper CT 13TH SYMP ON BIOTECHNOLOGY FOR FUELS AND CHEMICALS CY MAY 06-10, 1991 CL COLORADO SPRINGS, CO SP US DOE, NATL RENEWABLE ENERGY LAB, OAK RIDGE NATL LAB, GAS RES INST, BADGER ENGINEERS, COLORADO INST RES BIOTECHNOL, AMER CHEM SOC DE ASPEN; PROCESS INTEGRATION; COMPUTER-AIDED DESIGN; ETHYL ACETATE AB Ethanol is commercially produced by bioconversion and by hydration of ethylene. Bioconversion has the significant advantage that utilization of nonrenewable petroleum resources is minimized. Advanced bioprocesses for aqueous ethanol can also be integrated with down-stream systems for energy-efficient conversion to added-value chemicals, such as esters or other ethylene or ethanol derivatives. Since the energy-intensive step involving azeotrope dehydration is eliminated, net process energy requirements can be less than for production of anhydrous ethanol. Energy-economic assessments of a potential esterification process are described, where ethanol vapor in the presence of water from a bioreactor is catalytically converted to ethyl acetate. A commercial ASPEN process simulation program was used, and results were compared with an assessment based on a JPL computer model. Detailed evaluations of the sensitivity of cost of production to factors, such as material costs and annual production rates, were also completed. C1 JET PROP LAB,PASADENA,CA 91109. NR 12 TC 1 Z9 1 U1 0 U2 3 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 SN 0273-2289 J9 APPL BIOCHEM BIOTECH JI Appl. Biochem. Biotechnol. PD SPR PY 1992 VL 34-5 BP 515 EP 526 DI 10.1007/BF02920575 PG 12 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA HU375 UT WOS:A1992HU37500048 ER PT J AU TROUT, C CONTENT, D DAVILA, P AF TROUT, C CONTENT, D DAVILA, P TI ABERRATION-CORRECTED ASPHERIC GRATING DESIGNS FOR THE LYMAN FAR-ULTRAVIOLET SPECTROSCOPIC EXPLORER HIGH-RESOLUTION SPECTROGRAPH - A COMPARISON SO APPLIED OPTICS LA English DT Article DE ABERRATION CORRECTION; DIFFRACTION GRATING; FAR-ULTRAVIOLET SPECTROSCOPY AB Two approaches to reducing the optical aberration, of concave diffraction gratings have been studied to obtain candidate grating designs for the Lyman/Far-Ultraviolet Spectroscopic Explorer mission. The first approach involves shaping the grating substrate while using straight and equally spaced grooves. The second approach involves using a gating substrate with a relatively simple figure and holographically controlling the groove curvature and spacing. We analyze and compare specific designs derived from both approaches. RP TROUT, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 12 TC 5 Z9 5 U1 0 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 MAR 1 PY 1992 VL 31 IS 7 BP 943 EP 948 PG 6 WC Optics SC Optics GA HE657 UT WOS:A1992HE65700013 PM 20720704 ER PT J AU DAVILA, P CONTENT, D TROUT, C AF DAVILA, P CONTENT, D TROUT, C TI ABERRATION-CORRECTED ASPHERIC GRATINGS FOR FAR-ULTRAVIOLET SPECTROGRAPHS - HOLOGRAPHIC APPROACH SO APPLIED OPTICS LA English DT Article DE ABERRATION CORRECTION; DIFFRACTION GRATING; FAR-ULTRAVIOLET SPECTROSCOPY ID WAVES AB Two approaches to reducing the optical aberrations of concave diffraction gratings have been studied: holographically controlling the groove curvature and spacing, and shaping the optical substrate while keeping the grooves straight and equally spaced. We develop the theory of ellipsoidal holographic diffraction gratings and apply this theory to Rowland circle spectrographs. We show that ellipsoidal holographic gratings used in second order can yield high spectral resolutions across the spectral band. These gratings may be suitable for use in far-ultraviolet Rowland spectrographs with small bandpasses. RP DAVILA, P (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 21 TC 7 Z9 7 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAR 1 PY 1992 VL 31 IS 7 BP 949 EP 954 PG 6 WC Optics SC Optics GA HE657 UT WOS:A1992HE65700014 PM 20720705 ER PT J AU WATANABE, WO SMITH, SJ WICKLUND, RI OLLA, BL AF WATANABE, WO SMITH, SJ WICKLUND, RI OLLA, BL TI HATCHERY PRODUCTION OF FLORIDA RED TILAPIA SEED IN BRACKISHWATER TANKS UNDER NATURAL-MOUTHBROODING AND CLUTCH-REMOVAL METHODS SO AQUACULTURE LA English DT Article ID OREOCHROMIS-NILOTICUS; FRY AB Hatchery production of Florida red tilapia seed (eggs, sacfry and fry) in brackishwater (12 ppt) tanks was studied on Lee Stocking Island (Exuma Cays, Bahamas) under two methods of broodstock management. Six above-ground tanks (34.2 m2) were each stocked with 240 year-class 1 breeders (avg. wt. = 143 g) at a ratio of 3 females to 1 male. Seed production was monitored either under the natural-mouthbrooding method by collecting free-swimming (i.e., post-yolksac stage) fry from tanks every 8-16 days, or under the clutch-removal method by removing free-swimming fry from tanks, and eggs and sacfry from the mouths of brooding females every 15-16 days, and assessing the numbers of each. Seed production over a 3-month period under the natural-mouthbrooding method (3.3 seed m-2 day-1) was significantly lower (P < 0.001) than that obtained under the clutch-removal method (91.7 seed m-2 day-1) which is among the highest reported for tilapia hatcheries. Poor seed production under the natural-mouthbrooding method was attributable to cannibalism of eggs and fry by adults. Hatching success of eggs in upwelling incubators averaged 64.8% with effects of densities of 462, 923, 1385 and 1846/l not differing significantly (P > 0.05). Fry obtained from artificial incubation were significantly (P < 0.05) larger (9.9 mg vs. 7.5 mg) and more viable than those obtained through natural mouthbrooding as evidenced by higher survival (73.9% vs. 49.7%) during a 29-day sex-reversal period. The results suggest that the clutch-removal method, while more labor intensive, yields markedly higher numbers of viable fry for growout. C1 HATFIELD MARINE SCI CTR,NATL MARINE FISHERIES SERV,NW & ALASKA FISHERIES CTR,NEWPORT,OR 97365. RP WATANABE, WO (reprint author), CARIBBEAN MARINE RES CTR,805 E 46TH PL,VERO BEACH,FL 32963, USA. NR 34 TC 9 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD MAR 1 PY 1992 VL 102 IS 1-2 BP 77 EP 88 DI 10.1016/0044-8486(92)90290-2 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA HH272 UT WOS:A1992HH27200008 ER PT J AU MACK, WJ SELZER, RH POGODA, JM LEE, PL SHIRCORE, AM AZEN, SP BLANKENHORN, DH AF MACK, WJ SELZER, RH POGODA, JM LEE, PL SHIRCORE, AM AZEN, SP BLANKENHORN, DH TI COMPARISON OF COMPUTER-DERIVED AND HUMAN-DERIVED CORONARY ANGIOGRAPHIC END-POINT MEASURES FOR CONTROLLED THERAPY TRIALS SO ARTERIOSCLEROSIS AND THROMBOSIS LA English DT Article DE ATHEROSCLEROSIS; CLINICAL TRIALS; LESION ESTIMATION; QUANTITATIVE CORONARY ANGIOGRAPHY ID ARTERY DISEASE; COLESTIPOL-NIACIN; ATHEROSCLEROSIS; PROGRESSION; INTERVENTION; REGRESSION; DESIGN; DIET AB The Cholesterol Lowering Atherosclerosis Study, a randomized angiographic clinical trial, demonstrated the beneficial effect of niacin/colestipol plus diet therapy on coronary atherosclerosis. Outcome was determined by panel-based estimates (viewed in both still and cine modes) of percent stenosis severity and change in native artery and bypass graft lesions. Computer-based quantitative coronary angiography (QCA) was also used to measure lesion and bypass graft stenosis severity and change in individual frames closely matched in orientation, opacification, and cardiac phase. Both methods jointly evaluated 350 nonoccluded lesions. The correlation between QCA and panel estimates of lesion size was 0.70 (p < 0.0001) and for change in lesion size was 0.28 (p = 0.002). Agreement between the two methods in classifying lesion changes (i.e., regression, unchanged, or progression) occurred for 60% (210 of 350) of the lesions (kappa +/- SEM = 0.20 +/- 0.05, p < 0.001). The panel identified 442 nonoccluded lesions for which QCA stenosis measurements could not be obtained. Lesions not measurable by QCA included those with stenosis > 85% that could not be reliably edge tracked, segments with diffuse or ectatic disease that had no reliable reference diameter, and segments for which matched frames could not be located. Seventy-nine lesions, the majority between 21% and 40% stenosis, were identified and measured by QCA but were not identified by the panel. This comparison study demonstrates the need to consider available angiographic measurement methods in relation to the goals of their use. C1 UNIV SO CALIF,SCH MED,ATHEROSCLEROSIS RES INST,DEPT PREVENT MED,2025 ZONAL AVE,RMR 102,LOS ANGELES,CA 90033. UNIV SO CALIF,SCH MED,DEPT MED,LOS ANGELES,CA 90033. CALTECH,JET PROP LAB,PASADENA,CA 91109. FU NHLBI NIH HHS [R01-HL-23619] NR 21 TC 16 Z9 16 U1 0 U2 0 PU AMER HEART ASSOC PI DALLAS PA 7272 GREENVILLE AVENUE, DALLAS, TX 75231-4596 SN 1049-8834 J9 ARTERIOSCLER THROMB JI Arterioscler. Thromb. PD MAR PY 1992 VL 12 IS 3 BP 348 EP 356 PG 9 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA HJ916 UT WOS:A1992HJ91600012 PM 1547194 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 DYNAMICS OF THE YOUNG LMC CLUSTER NGC-1866 SO ASTRONOMICAL JOURNAL LA English DT Article ID LARGE MAGELLANIC CLOUD; RANDOM GRAVITATIONAL ENCOUNTERS; GLOBULAR-CLUSTERS; ELLIPTICAL GALAXIES; CONVECTIVE OVERSHOOT; VELOCITY DISPERSIONS; RADIAL-VELOCITIES; SPHERICAL SYSTEMS; INDIVIDUAL STARS; MASS FUNCTION AB V-band CCD images of the young LMC cluster NGC 1866 out to a projected radius R approximately 100 pc were obtained using the 1.0 m telescope at Las Campanas. In addition, radial velocities with a mean precision of 1.0 km s-1 were measured for 69 member supergiants using the echelle spectrograph on the 2.5 m telescope. The luminosity profile is well described by a power law. The total cluster luminosity is L(V infinity) = 6.5 +/- 0.3 x 10(5) L.. A star-subtracted, median-filtered U frame was used to determine photometric shape parameters. In the region 4 less-than-or-equal-to R (pc) less-than-or-equal-to 12, the cluster has a mean ellipticity of epsilon = 0.17 +/- 0.06 and a minor axis position angle alpha = 125-degrees +/- 5-degrees. The stellar radial velocities indicate that NGC 1866 has a systemic velocity of upsilon(ave) = 301.2 +/- 1.0 km s-1 and is rotating around an axis at a position angle of 100 +/- 25-degrees with a peak velocity of 1.3 +/- 0.5 km s-1. A comparison of the derived values for NGC 1866 and the theoretical upsilon(0)/sigma(0) - epsilon relationship indicates that the observed flattening is consistent with rotation. The cluster mass was determined using a maximum likelihood estimator to compare the observed radial velocities to various orbital models yielding M infinity = 1.25 and 1.35 +/- 0.25 x 10(5) M. and M/L(V) = 0.19 - 0.21 +/- 0.04 M./L. for models with and without a rotational component, respectively. This technique has been used to determine the nature of the orbital anisotropies and to justify the addition of the rotation term to the cluster velocity field. The quality of the fits for models with rotation is clearly superior to those without and isotropic orbits agree best with the data in both cases. Depending on the actual age of the cluster, the best estimate for the average slope of the mass function is x = 1.3 +/- 0.15 (tau = 2.0 x 10(8) yr) or x = 1.82 +/- 0.1 (tau = 1.0 x 10(8) yr). C1 CARNEGIE INST WASHINGTON,OBSERV,PASADENA,CA 91101. CALTECH,JET PROP LAB,CTR INFRARED PROC,PASADENA,CA 91125. RP FISCHER, P (reprint author), MCMASTER UNIV,DEPT PHYS,HAMILTON L8S 4M1,ONTARIO,CANADA. OI Welch, Doug/0000-0002-2350-0898 NR 40 TC 42 Z9 42 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 MAR PY 1992 VL 103 IS 3 BP 857 EP 870 DI 10.1086/116107 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HE673 UT WOS:A1992HE67300014 ER PT J AU LINDAL, GF AF LINDAL, GF TI THE ATMOSPHERE OF NEPTUNE - AN ANALYSIS OF RADIO OCCULATION DATA ACQUIRED WITH VOYAGER-2 SO ASTRONOMICAL JOURNAL LA English DT Article ID OCCULTATION MEASUREMENTS; INFRARED OBSERVATIONS; SCIENCE OBSERVATIONS; GRAVITY-FIELD; TRACKING DATA; URANUS; SYSTEM; SATELLITES; TEMPERATURE; PIONEER AB Recordings of the tracking signals received from Voyager 2 during its occultation by Neptune have been used to study the vertical structure of Neptune's atmosphere. The measurements, which began at a planetographic latitude of 62-degrees north and ended near 45-degrees south, cover an altitude interval of about 5000 km. Inversion and interpretation of the occultation data have provided new information on the distribution of free electrons in Neptune's ionosphere, the thermal structure and composition of its troposphere and stratosphere, and the zonal winds below the 1.7 bar level in the troposphere. The 1 bar isobaric surface has equatorial and polar radii of 24 766 +/- 15 km and 24 342 +/- 30 km, respectively, and a corresponding oblateness of 0.0171 +/- 0.0014. At this pressure level, the temperature was 72 +/- 2 K. The tropopause was detected approximately 40 km above the 1 bar level at a pressure of about 100 mbar. A comparison with infrared observations indicates that the gas at the tropopause consists of 78%-84% hydrogen by number density with the rest being mostly helium. The temperature in this region was 52 +/- 2 K. Above the tropopause, the temperature is increasing with altitude reaching 130 +/- 12 K near the 0.3 mbar level. A 2-3 km thick layer with a small refractivity scale height whose top was detected 14 km below the 1 bar level, may be a region where the CH4 mixing ratio is decreasing rapidly with increasing altitude-perhaps as a result of vapor condensation effects that produce haze. For the nominal model derived from the ingress measurements, this interpretation yielded a CH4 mixing ratio of 2% at the base of the layer where the pressure was about 1.9 bars. Uncertainties in the atmospheric rotation period affect the interpretation of the measurements below the 1.7 bar level. A rotation period of 14.2 +/- 0.3 hr was found to be consistent with the ingress data acquired at 60-degrees north latitude, and was adopted for the nominal model. This rotation period corresponds to an eastward zonal wind velocity of 176 +/- 32 m/s relative to the magnetic field. Data acquired between 38-degrees and 15-degrees south during egress indicate westward zonal winds with velocities ranging from 100 to 400 m/s below the 1.7 bar level. Ammonia vapor was assumed to be the principal microwave absorber limiting the depth of the measurements in the troposphere. At the lowest level where the link was detected during ingress, the nominal model has a pressure and temperature of 6.3 bars and 135 K, respectively. The ammonia mixing ratio at this level was 500 +/- 150 parts per billion. RP LINDAL, GF (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 62 TC 180 Z9 181 U1 2 U2 16 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 MAR PY 1992 VL 103 IS 3 BP 967 EP 982 DI 10.1086/116119 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HE673 UT WOS:A1992HE67300026 ER PT J AU HULOT, E VILMER, N CHUPP, EL DENNIS, BR KANE, SR AF HULOT, E VILMER, N CHUPP, EL DENNIS, BR KANE, SR TI GAMMA-RAY AND X-RAY TIME PROFILES EXPECTED FROM A TRAP-PLUS-PRECIPITATION MODEL FOR THE 7 JUNE 1980 AND 27 APRIL 1981 SOLAR-FLARES SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE SUN, BURSTS; SUN, FLARES; SUN, X-RAYS; SUN, GAMMA-RAYS ID HINOTORI SPACECRAFT; EMISSION; LINE; BURSTS; ACCELERATION; SATELLITE; ELECTRONS; PARTICLES; PROTONS AB Hard X-ray and prompt gamma-ray line emissions are the most direct signatures of, respectively, electron and ion acceleration during solar flares. The peak time of the gamma-ray emission for some events is delayed with respect to the peak time of the hard X-ray flux. These delays are either interpreted as evidence of a two-step acceleration process or as the result of the partial trapping and/or propagation of the particles from the acceleration region to the emission sites. It was shown earlier that hard X-ray and prompt gamma-ray line delays can be qualitatively reproduced in the frame of the latter hypothesis with models describing the time dependent transport of energetic electrons and ions between these two sites. Here we focus on the close examination of the temporal evolution of X-ray and gamma-ray fluxes for the 7 June 1980 and 27 April 1981 events which exhibit delays between X-ray and gamma-ray maxima. The parameters of the ambient medium and of the accelerated particles are deduced for the two events and it is shown that the relative timing of X-ray and gamma-ray emissions is quantitatively reproduced in the present context. The implications of a coronal contribution to gamma-ray line emission are also discussed for these two events. C1 OBSERV PARIS, SECT MEUDON, DASOP, F-92195 MEUDON, FRANCE. CNRS, URA 324, F-92195 MEUDON, FRANCE. UNIV NEW HAMPSHIRE, DEPT PHYS, DURHAM, NH 03824 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV CALIF BERKELEY, SPACE SCI LAB, BERKELEY, CA 94720 USA. RI Dennis, Brian/C-9511-2012 NR 56 TC 25 Z9 26 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 MAR PY 1992 VL 256 IS 1 BP 273 EP 285 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HH020 UT WOS:A1992HH02000036 ER PT J AU ZHAO, JH BURNS, JO NORMAN, ML SULKANEN, ME AF ZHAO, JH BURNS, JO NORMAN, ML SULKANEN, ME TI INSTABILITIES IN ASTROPHYSICAL JETS .2. NUMERICAL SIMULATIONS OF SLAB JETS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES JETS; HYDRODYNAMICS; INSTABILITIES; METHODS NUMERICAL; SHOCK WAVES ID EXTRAGALACTIC RADIO-SOURCES; VLA OBSERVATIONS; SPATIAL STABILITY; MODEL; DYNAMICS; GALAXIES; MORPHOLOGY; HOTSPOTS; TRAILS AB In this paper, we describe numerical simulations of an unstable supersonic slab-symmetric jet. The instabilities within the jet are characterized by growing internal body waves and their coupled surface waves that are also predicted in linear perturbation theory. The characteristic theory of fluid dynamics is used to help interpret the wave morphologies. We demonstrate that these waves can be excited by imposing an arbitrary disturbance. From our numerical simulations, we find that the sound waves propagating against the flow slow down as they propagate outward, and they grow in amplitude. These waves eventually disrupt the jet at a certain length. This disruption length is related to the jet Mach number and the perturbation intensity. Thus, the Mach number of a jet observed with a radio telescope can be estimated by measuring the disruption length and estimating the perturbation intensity. The jet Mach numbers in radio tailed sources determined in this way agree quite well with estimates from ram pressure bending arguments. The wiggles and flares observed in many extragalactic jets, especially in tailed radio sources, appear to be intimately related to instabilities and the jet disruption process. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,XRAY ASTRON BRANCH,HUNTSVILLE,AL 35812. UNIV NEW MEXICO,INST ASTROPHYS,ALBUQUERQUE,NM 87131. NEW MEXICO STATE UNIV,DEPT ASTRON,LAS CRUCES,NM 88003. UNIV ILLINOIS,BECKMAN INST,DEPT ASTRON,URBANA,IL 61801. UNIV ILLINOIS,NATL CTR SUPERCOMP APPL,URBANA,IL 61801. RP ZHAO, JH (reprint author), NATL RADIO ASTRON OBSERV,POB O,SOCORRO,NM 87801, USA. NR 44 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 MAR 1 PY 1992 VL 387 IS 1 BP 83 EP & DI 10.1086/171062 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF369 UT WOS:A1992HF36900008 ER PT J AU DAVIDSON, JA WERNER, MW WU, X LESTER, DF HARVEY, PM JOY, M MORRIS, M AF DAVIDSON, JA WERNER, MW WU, X LESTER, DF HARVEY, PM JOY, M MORRIS, M TI THE LUMINOSITY OF THE GALACTIC-CENTER SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXY CENTER; INFRARED INTERSTELLAR CONTINUUM ID FAR-INFRARED OBSERVATIONS; CENTRAL PARSEC; SAGITTARIUS-A; INTERSTELLAR GRAINS; MASS-DISTRIBUTION; MAGNETIC-FIELD; IONIZED-GAS; SGR-A; GALAXY; DUST AB We present high signal-to-noise 50 and 90-mu-m continuum maps of the central 5' x 4' of the Galaxy made from observations on the Kuiper Airborne Observatory. This set of data was suitable for the implementation of super-resolution techniques, enabling us to achieve effective angular resolutions of 10" x 19" at 50-mu-m and 15" x 24" at 90-mu-m. We present dust and luminosity distribution models which are consistent with the data. In summary, our data are consistent with a flared disk of dust, centered on the position of Sgr A*, having a central cavity with a radius of 1 pc. There is also strong evidence for a large amount of dust between the northern and eastern ionized arms located within the cavity. This "tongue" of dust is probably optically thick at ultraviolet (UV) and visible wavelengths. Both smooth and clumped dust distributions, consistent with the disk and central cavity outlined above, were considered. It was found that for the smooth distribution, the dust heating is consistent with the data only for a central UV source of a few x 10(6) L.; a larger luminosity would result in a luminosity distribution very different from that observed. In this situation most of the dust in the disk is heated by the late-type stellar population at the Galactic Center. For the clumped distribution, the luminosity distribution can be matched to that observed for a central UV source of approximately 10(7) L.. In this case the dust in the disk is heated equally by the luminous central source and the stellar population. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. STANFORD UNIV,DEPT ELECT ENGN,STANFORD,CA 94305. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. UNIV CALIF LOS ANGELES,DEPT ASTRON 156205,LOS ANGELES,CA 94035. RP DAVIDSON, JA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 44 TC 71 Z9 72 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 MAR 1 PY 1992 VL 387 IS 1 BP 189 EP 211 DI 10.1086/171071 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF369 UT WOS:A1992HF36900017 ER PT J AU HEAP, SR CORCORAN, MF AF HEAP, SR CORCORAN, MF TI PROPERTIES OF THE MASSIVE X-RAY BINARY 4U-1700-37 = HD-153919 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES ECLIPSING; STARS EMISSION-LINE, BE; STARS INDIVIDUAL (HD 153919); STARS NEUTRON; ULTRAVIOLET STARS; X-RAYS STARS ID RADIATION-DRIVEN WINDS; HOT LUMINOUS STARS; STELLAR WINDS; O-STARS; 4U 1700-37; MODELS AB We re-examine the system parameters for the massive X-ray binary (MXRB) 4U 1700-37 in the light of modern spectroscopic theory and new ultraviolet and X-ray data. This system is composed of HD 153919, an O6f star having a stronger wind, and an accreting neutron star. In interpreting X-ray light curves for this system obtained from various X-ray experiments operating at different energies, we take into account the opacity of the wind to low-energy X-rays. Upon adopting the X-ray light curve from a high-energy experiment, OSO 8, we derive the following properties for the Of star: M(O) = 52 +/- 2 M., T(eff) = 42,000 K, log g = 3.6; a binary separation, a = 2.0 R(O); and a neutron-star mass, M(x) = 1.8 +/- 0.4 M.. These revised parameters for the Of component are in accord with the parameters of single Of stars, and hence, the problem that "the O star is undermassive by a factor of 2" (Conti 1978) is resolved. The revised value for the binary separation, a, results in improved parameters for the wind from the Of star: (1) the ratio of terminal velocity of the wind to photospheric escape velocity agrees with those of single 0 stars; (2) the discrepancy between the values of the wind acceleration parameter, beta, derived from X-ray and UV data is resolved; and (3) the acceleration of the wind is similar to that of single OB star winds. Finally, the revised system parameters aid in our understanding of the evolutionary history of the binary. We suggest that the supernova explosion producing the neutron star in 4U 1700-37 occurred over a million years ago when HD 153919 was still on the main sequence. The explosion nearly disrupted the system, leaving the stellar components in highly eccentric orbits. Since then, HD 153919 has evolved off the zero-age main sequence to become an O supergiant with an intense wind, which serves to power the X-ray emission. RP HEAP, SR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 681,GREENBELT,MD 20771, USA. RI heap, sara/E-2237-2012 NR 39 TC 48 Z9 48 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1992 VL 387 IS 1 BP 340 EP 346 DI 10.1086/171086 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF369 UT WOS:A1992HF36900032 ER PT J AU KETO, E BALL, R ARENS, J JERNIGAN, G MEIXNER, M AF KETO, E BALL, R ARENS, J JERNIGAN, G MEIXNER, M TI MIDINFRARED IMAGING OF MARKARIAN-231 AND ARP-220 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, NUCLEI ID BRIGHT GALAXY SAMPLE; CO EMISSION; RESOLUTION AB High angular resolution observations of Arp 220 and Mrk 231 provide images of the nuclei and show that the source of the strong mid-IR emission is confined to regions less than about 0".5 or 400 pc in diameter in Mrk 231 and less than 1".5 x 0".9 or 320 x 530 pc in Arp 220. If much of the far-IR emission also derives from such a small region, the implied radiation densities are quite high, equivalent to one O star pc-3. Although in normal galaxies the near-IR traces an older population of evolved, cool stars, such high radiation densities in the IR bright galaxies suggest the possibility that the spatial correlation observed between the near-IR, mid-IR, and radio may hold because emission in all three bands is associated with hot interstellar gas and dust. C1 UNIV HAWAII,NASA,INFRARED TELESCOPE FACIL,HONOLULU,HI 96822. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP KETO, E (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 23 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 MAR 1 PY 1992 VL 387 IS 1 BP L17 EP L19 DI 10.1086/186295 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF370 UT WOS:A1992HF37000004 ER PT J AU MCCARTHY, PJ ELSTON, R EISENHARDT, P AF MCCARTHY, PJ ELSTON, R EISENHARDT, P TI THE LY-ALPHA H-ALPHA RATIO IN HIGH-REDSHIFT RADIO GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ACTIVE; GALAXIES, INTERSTELLAR MATTER ID EXTINCTION; EVOLUTION; DISCOVERY; EMISSION AB We present the first spectroscopic detections of H-alpha emission from radio galaxies at z > 2. Narrow H-alpha emission has been detected at the 5 sigma-level in the radio galaxies B3 0731 + 438 at z = 2.43 and MRC 0406 - 244 at z = 2.44. After correcting for foreground Galactic extinction we derive Lyman-alpha/H-alpha ratios of 4.7 and 3.5, implying E(B - V) = 0.1 +/- 0.06(3-sigma) and E(B - V) = 0.13 +/- 0.08 for the two galaxies. These should be regarded as upper limits to the reddening since multiple scatterings may contribute to the destruction of Ly-alpha. The H-alpha + [N II] emission lines contribute 20% +/- 6% (0731 + 438) and 12% +/- 4% (0406 - 244) of the broad-band fluxes at K. The effect of the implied reddening and emission-line contributions result in an observed frame r - K color which is bluer by 0.7-0.8 mag, but have a negligible effect on M(K). Such a large change in the spectral energy distribution can have a substantial impact on the inferred ages and star-formation histories. C1 NATL OPT ASTRON OBSERV,TUCSON,AZ 85726. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP MCCARTHY, PJ (reprint author), OBSERV CARNEGIE INST WASHINGTON,813 SANTA BARBARA ST,PASADENA,CA 91101, USA. NR 31 TC 38 Z9 38 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 1992 VL 387 IS 1 BP L29 EP & DI 10.1086/186298 PN 2 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HF370 UT WOS:A1992HF37000007 ER PT J AU BHATIA, AK KASTNER, SO AF BHATIA, AK KASTNER, SO TI THE OPTICALLY THICK C-III SPECTRUM .1. TERM POPULATIONS AND MULTIPLET INTENSITIES AT LOWER OPTICAL DEPTHS SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE ATOMIC PROCESSES ID ELECTRON-IMPACT-EXCITATION; LINES; OPACITY; IONS; SEQUENCE; RATIOS; IUE AB The C III spectrum is studied quantitatively under both optically thin and optically thick conditions, yielding term populations and line/multiplet intensities for column lengths from zero to 10(18) cm-2. The roles of escape probabilities and line profiles in the calculation are discussed in some detail. It is shown that use of the fully integrated escape factor, rather than the more appropriate monodirectional escape probability, can lead to appreciable errors in calculated intensities. The results for populations and intensities allow us to identify two unassigned features in the solar EUV spectrum of Vernazza & Reeves as C III multiplets, and to establish that an unidentified infrared solar feature at 8500.32 angstrom, seen in both absorption (Fraunhofer) and emission (chromospheric) spectra, is the C III transition 2s3s(1S)-2s3p(1P). In addition to the principal results we tabulate Voigt parameters for the C III lines and multiplets, obtained by a modified semiclassical method. We also propose and use a new, unambiguous notation for the numerous line ratios present in a typical spectrum, which we believe to be an improvement over present arbitrary notations. C1 MATH SCI CONSULTANTS INC,GREENBELT,MD 20770. RP BHATIA, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON BRANCH,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 40 TC 16 Z9 16 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 1992 VL 79 IS 1 BP 139 EP 156 DI 10.1086/191648 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HE442 UT WOS:A1992HE44200007 ER PT J AU KYRIAKOPOULOS, KJ SARIDIS, GN AF KYRIAKOPOULOS, KJ SARIDIS, GN TI DISTANCE ESTIMATION AND COLLISION PREDICTION FOR ONLINE ROBOTIC MOTION PLANNING SO AUTOMATICA LA English DT Note DE COLLISION AVOIDANCE; COLLISION PREDICTION; DISTANCE FUNCTIONS; RANDOM SEARCH AB An efficient method for computing the minimum distance and predicting collisions between moving objects is presented. This problem has been incorporated in the framework of an in-line motion planning algorithm to satisfy collision avoidance between a robot and moving objects modelled as convex polyhedra. In the beginning, the deterministic problem where the information about the objects is assumed to be certain is examined. If instead of the Euclidean norm, L1 or L infinity norms are used to represent distance, the problem becomes a linear programming problem. The stochastic problem is formulated, where the uncertainty is induced by sensing and the unknown dynamics of the moving obstacles. Two problems are considered: First, filtering of the distance between the robot and the moving object, at the present time. Second, prediction of the minimum distance in the future, in order to predict the collision time. C1 RENSSELAER POLYTECH INST,NASA,CTR INTELLIGENT ROBOT SYST SPACE EXPLORAT,TROY,NY 12180. NR 18 TC 7 Z9 7 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0005-1098 J9 AUTOMATICA JI Automatica PD MAR PY 1992 VL 28 IS 2 BP 389 EP 394 DI 10.1016/0005-1098(92)90124-X PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA HP025 UT WOS:A1992HP02500013 ER PT J AU KEIL, LC MCKEEVER, KH SKIDMORE, MG HINES, J SEVERS, WB AF KEIL, LC MCKEEVER, KH SKIDMORE, MG HINES, J SEVERS, WB TI THE EFFECT OF HEAD-DOWN TILT AND WATER IMMERSION ON INTRACRANIAL-PRESSURE IN NONHUMAN-PRIMATES SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID RENAL RESPONSES; VOLUME EXPANSION; VASOPRESSIN AB A headward fluid shift occurs in humans exposed to spaceflight. This shift is thought to be the stimulus for the observed reduction in plasma volume, and may produce a sustained rise in intracranial pressure (ICP). In order to determine the effect of head-down tilt (HDT) and water immersion on intracranial pressure (ICP), five anesthetized rhesus monkeys were fitted with intracranial pressure-monitoring transducers and subjected to -6-degrees HDT followed by head-out thermoneutral (34.7-degrees) water immersion. ICP was elevated from 3.8 +/- 1.1 mm Hg in the horizontal control period to 5.3 +/- 1.3 mm Hg (p < 0.05) during the 15 min pre-immersion HDT. When seated in the empty immersion tank, ICP stabilized at -6.3 +/- 1.3 mm Hg for the control period and increased to -2.2 +/- 1.9 mm Hg (p < 0.05) when the water level was maintained for 30 min at the starnal notch. The ICP returned toward pre-immersion levels (-5.5 +/- 1.4 mm Hg) as the tank was drained. Mean blood pressure (MBP) remained constant during the pre-immersion tilt test. In the pre-immersion control period, MBP was 91 +/- 3 mm Hg compared to 90 +/- 4 mm Hg (p > 0.05) during immersion and 82 +/- 1 mm Hg (p < 0.05) in the post-immersion recovery period. In summary, exposure of rhesus monkeys to either head-down tilt or water immersion produced a prompt rise in ICP during the stimulus period. The magnitude of the increased ICP was greater with water immersion than with -6-degrees HDT. However, ICP did not appear to rise to pathological levels. C1 OHIO STATE UNIV,COLL VET MED,DEPT VET CLIN SCI,COLUMBUS,OH 43210. PENN STATE UNIV,MILTON S HERSHEY MED CTR,COLL MED,DEPT PHARMACOL,HERSHEY,PA 17033. RP KEIL, LC (reprint author), NASA,AMES RES CTR,DIV SPACE LIFE SCI,239-17,MOFFETT FIELD,CA 94035, USA. NR 23 TC 27 Z9 28 U1 1 U2 2 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAR PY 1992 VL 63 IS 3 BP 181 EP 185 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA HF149 UT WOS:A1992HF14900004 PM 1567318 ER PT J AU STOLARSKI, RS AF STOLARSKI, RS TI OBSERVATION OF GLOBAL STRATOSPHERIC OZONE CHANGE SO BERICHTE DER BUNSEN-GESELLSCHAFT-PHYSICAL CHEMISTRY CHEMICAL PHYSICS LA English DT Article; Proceedings Paper CT DISCUSSION MEETING ON PHYSICS AND CHEMISTRY OF THE ATMOSPHERE CY OCT 07-09, 1991 CL SCHLIERSEE, GERMANY SP DEUT BUNSEN GESELL PHYS CHEM DE ATMOSPHERIC CHEMISTRY; PHOTOCHEMISTRY ID INSITU ER-2 DATA; ANTARCTIC VORTEX; CLO; LATITUDE; DESTRUCTION; O-3; BRO AB Measurements of the total column amount of ozone from the Total Ozone Mapping Spectrometer(TOMS) on the Nimbus 7 satellite have now been made for 13 years. They show that the 1991 Antarctic ozone hole again had a pronounced minimum in early October; making four of the last five years with deep ozone holes. Global scale measurements by TOMS show no trend in total ozone near the equator, but a significant trend at northern middle and high latitudes. This trend has a pronounced seasonal variation with maximum in winter. The observed trend is significantly larger than the predictions of gas-phase photochemical models. RP STOLARSKI, RS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. RI Stolarski, Richard/B-8499-2013 OI Stolarski, Richard/0000-0001-8722-4012 NR 34 TC 0 Z9 0 U1 0 U2 1 PU VCH PUBLISHERS INC PI DEERFIELD BEACH PA 303 NW 12TH AVE, DEERFIELD BEACH, FL 33442-1788 SN 0005-9021 J9 BER BUNSEN PHYS CHEM JI Ber. Bunsen-Ges. Phys. Chem. Chem. Phys. PD MAR PY 1992 VL 96 IS 3 BP 257 EP 263 PG 7 WC Chemistry, Physical SC Chemistry GA HR523 UT WOS:A1992HR52300004 ER PT J AU POLACHECK, T MOUNTAIN, D MCMILLAN, D SMITH, W BERRIEN, P AF POLACHECK, T MOUNTAIN, D MCMILLAN, D SMITH, W BERRIEN, P TI RECRUITMENT OF THE 1987 YEAR CLASS OF GEORGES BANK HADDOCK (MELANOGRAMMUS-AEGLEFINUS) - THE INFLUENCE OF UNUSUAL LARVAL TRANSPORT SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID COD AB Unusually strong along-shelf surface flow in the spring of 1987 transported haddock (Melanogrammus aeglefinus) larvae westward from spawning grounds on Georges Bank into the Middle Atlantic Bight, some as far as 400 km beyond the limits of their normal distribution. 0-Group haddock survived in the Bight in record numbers. Their center of abundance occurred along the outer half of the shelf from Delaware Bay to Martha's Vineyard where more than 97% of the 0-group fish resided in the fall of 1987. Juveniles remained more abundant in the Bight than on the bank through the spring of 1988. Collective evidence suggests that survivors returned to Georges Bank during the late spring/early summer of 1988. The estimated number of 0-group fish in the 1987 year class exceeded all previous estimates from a 27-yr time series which included the 1963 year class, the largest recruited to the fishery since record keeping began in 1931. C1 NOAA,NATL MARINE FISHERIES SERV,SANDY HOOK LAB,HIGHLANDS,NJ 07732. RP POLACHECK, T (reprint author), NOAA,NATL MARINE FISHERIES SERV,WOODS HOLE LAB,WOODS HOLE,MA 02543, USA. NR 39 TC 36 Z9 36 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAR PY 1992 VL 49 IS 3 BP 484 EP 496 DI 10.1139/f92-057 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA HJ150 UT WOS:A1992HJ15000008 ER PT J AU Rampino, MR Caldeira, K AF Rampino, Michael R. Caldeira, Ken TI EPISODES OF TERRESTRIAL GEOLOGIC ACTIVITY DURING THE PAST 260 MILLION YEARS: A QUANTITATIVE APPROACH SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article DE Episodes; geologic activity; correlation; biologic extinctions; periodicity; extraterrestrial impacts AB Records of major geologic events of the past similar to 260 Myr including: biologic extinction events, ocean-anoxic and black-shale events, major changes in sea level, major evaporite (salt) deposits, continental flood-basalt eruptions, first-order discontinuities in sea-floor spreading, and major mountain building events, have been aggregated and analyzed with moving-window and spectral techniques that facilitate recognition of clustering and possible cyclicity. Significant clustering of events suggests a model in which changes in rates and directions of sea-floor spreading ("ridge jumps") are associated with episodic rifting, volcanism, mountain building, global sea level and changes in the composition of the earth's atmosphere via the carbon cycle. Variation in atmospheric CO(2) affects global climate, ocean circulation and marine productivity. The geologic data formally show a statistically significant underlying periodicity of 26.6 Myr for the Mesozoic and Cenozoic (the exact period differs with minor changes in geologic dating). Phase information suggests that the most recent maximum of the cycle occurred within the last 9 Myr, and may be close to the present time. The quasi-regular pulses of activity might be related to internal earth processes. However, a similar periodicity in impact craters and in galactic dynamics, and a one-to-one correlation among mass extinctions, large impact events, and flood-basalt volcanism, indicate an extraterrestrial pacemaker. C1 [Rampino, Michael R.] NYU, Earth Syst Grp, New York, NY 10003 USA. [Rampino, Michael R.] NASA, Goddard Inst Space Studies, New York, NY 10025 USA. [Caldeira, Ken] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. [Caldeira, Ken] Penn State Univ, Ctr Earth Syst Sci, University Pk, PA 16802 USA. RP Rampino, MR (reprint author), NYU, Earth Syst Grp, New York, NY 10003 USA. RI Caldeira, Ken/E-7914-2011 NR 70 TC 22 Z9 22 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PD MAR PY 1992 VL 54 IS 1-3 BP 143 EP 159 DI 10.1007/BF00049549 PG 17 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA V05NB UT WOS:000207131600011 ER PT J AU NEELIN, JD LATIF, M ALLAART, MAF CANE, MA CUBASCH, U GATES, WL GENT, PR GHIL, M GORDON, C LAU, NC MECHOSO, CR MEEHL, GA OBERHUBER, JM PHILANDER, SGH SCHOPF, PS SPERBER, KR STERL, A TOKIOKA, T TRIBBIA, J ZEBIAK, SE AF NEELIN, JD LATIF, M ALLAART, MAF CANE, MA CUBASCH, U GATES, WL GENT, PR GHIL, M GORDON, C LAU, NC MECHOSO, CR MEEHL, GA OBERHUBER, JM PHILANDER, SGH SCHOPF, PS SPERBER, KR STERL, A TOKIOKA, T TRIBBIA, J ZEBIAK, SE TI TROPICAL AIR-SEA INTERACTION IN GENERAL-CIRCULATION MODELS SO CLIMATE DYNAMICS LA English DT Review ID EASTERN EQUATORIAL PACIFIC; NINO SOUTHERN OSCILLATION; PLANETARY BOUNDARY-LAYER; WIND STRESS PATTERNS; EL-NINO; SURFACE TEMPERATURE; OCEAN MODEL; WORLD OCEAN; SEASONAL CYCLE; ATMOSPHERIC CIRCULATION AB An intercomparison is undertaken of the tropical behavior of 17 coupled ocean-atmosphere models in which at least one component may be termed a general circulation model (GCM). The aim is to provide a taxonomy-a description and rough classification-of behavior across the ensemble of models, focusing on interannual variability. The temporal behavior of the sea surface temperature (SST) field along the equator is presented for each model, SST being chosen as the primary variable for intercomparison due to its crucial role in mediating the coupling and because it is a sensitive indicator of climate drift. A wide variety of possible types of behavior are noted among the models. Models with substantial interannual tropical variability may be roughly classified into cases with propagating SST anomalies and cases in which the SST anomalies develop in place. A number of the models also exhibit significant drift with respect to SST climatology. However, there is not a clear relationship between climate drift and the presence or absence of interannual oscillations. In several cases, the mode of climate drift within the tropical Pacific appears to involve coupled feedback mechanisms similar to those responsible for El Nino variability. Implications for coupled-model development and for climate prediction on seasonal to interannual time scales are discussed. Overall, the results indicate considerable sensitivity of the tropical coupled ocean-atmosphere system and suggest that the simulation of the warm-pool/cold-tongue configuration in the equatorial Pacific represents a challenging test for climate model parameterizations. C1 MAX PLANCK INST METEOROL, W-2000 HAMBURG, GERMANY. KONINKLIJK NEDERLANDS METEOROL INST, DE BILDT, NETHERLANDS. GEOPHYS FLUID DYNAM LAB, PRINCETON, NJ 08542 USA. PRINCETON UNIV, ATMOSPHER & OCEAN SCI PROGRAM, PRINCETON, NJ 08542 USA. METEOROL RES INST, TSUKUBA, IBARAKI 305, JAPAN. COLUMBIA UNIV, LAMONT DOHERTY GEOL OBSERV, PALISADES, NY 10964 USA. UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. UNIV CALIF LOS ANGELES, INST GEOPHYS & PLANETARY PHYS, LOS ANGELES, CA 90024 USA. NASA, GODDARD SPACE FLIGHT CTR, HYDROSPHER PROC LAB, GREENBELT, MD 20771 USA. UNIV OXFORD, CLARENDON LAB, HOOKE INST ATMOSPHERE RES, METEOROL UNIT, OXFORD OX1 3PU, ENGLAND. RP NEELIN, JD (reprint author), UNIV CALIF LOS ANGELES, DEPT ATMOSPHER SCI, LOS ANGELES, CA 90024 USA. RI Neelin, J. David/H-4337-2011; Cane, Mark/I-8086-2012; Sperber, Kenneth/H-2333-2012; Latif, Mojib/C-2428-2016 OI Latif, Mojib/0000-0003-1079-5604 NR 136 TC 157 Z9 165 U1 0 U2 11 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD MAR PY 1992 VL 7 IS 2 BP 73 EP 104 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HL450 UT WOS:A1992HL45000002 ER PT J AU STEINBERG, TA WILSON, DB BENZ, F AF STEINBERG, TA WILSON, DB BENZ, F TI THE BURNING OF METALS AND ALLOYS IN MICROGRAVITY SO COMBUSTION AND FLAME LA English DT Article AB Use of high-pressure oxygen systems in space applications requires an understanding of how metals and alloys burn in microgravity. The present work involved burning rods of 2219 aluminum, 316 stainless steel, iron, and titanium, and sheets and meshes of 316 stainless steel in the 2.2-s drop tower at NASA Lewis Research Center. In microgravity, the metals (and alloys) and configurations tested burned vigorously, and the following was observed: (a) the absence of the buoyant force does not cause extinguishment of combustion; the molten ball is well-mixed over the duration of an experiment; (b) the regression rate of the melting interface of the cylindrical rods is significantly greater than in normal gravity; (c) ignition of adjacent materials readily occurs; (d) flammability of sample shapes, for example, thin sheets, which extinguish in normal gravity, is enhanced and samples burn to completion; (e) volatile combustion products are produced. an event that does not occur under similar conditions in normal gravity, (f) as occurs in the normal gravity combustion or iron rods, excess oxygen above stoichiometric requirements is contained in the formed molten ball; and (g) a similar dependency exists in microgravity to that in normal gravity between regression rate of the melting interface and oxygen pressure and rod diameter. Four of the above phenomena (b, c, d, and e) can be attributed to higher temperatures that result from the retention of all the reacting mass in the molten ball. C1 NASA,WHITE SANDS TEST FACIL,LAS CRUCES,NM. RP STEINBERG, TA (reprint author), LOCKHEED ESC,WHITE SANDS TEST FACIL,LAS CRUCES,NM, USA. OI Steinberg, Theodore/0000-0002-9270-4130 NR 21 TC 14 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAR PY 1992 VL 88 IS 3-4 BP 309 EP 320 DI 10.1016/0010-2180(92)90037-P PG 12 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA HJ453 UT WOS:A1992HJ45300004 ER PT J AU LOHNER, R CAMBEROS, J MERRIAM, M AF LOHNER, R CAMBEROS, J MERRIAM, M TI PARALLEL UNSTRUCTURED GRID GENERATION SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID ELEMENT MESH GENERATION; TESSELLATION AB A parallel unstructured grid generation algorithm is presented and implemented on the INTEL hypercube. Different processor hierarchies are discussed, and the appropriate hierarchies for mesh generation and mesh smoothing are selected. A domain-splitting algorithm for unstructured grids, which tries to minimize the surface-to-volume ratio of each subdomain, is described. This splitting algorithm is employed both for grid generation and grid smoothing. Results obtained on the INTEL hypercube demonstrate the effectiveness of the algorithms developed. C1 NASA,AMES RES CTR,CFD BRANCH,MOFFETT FIELD,CA 94035. RP LOHNER, R (reprint author), GEORGE WASHINGTON UNIV,SEAS,CMEE,WASHINGTON,DC 20052, USA. NR 23 TC 37 Z9 38 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD MAR PY 1992 VL 95 IS 3 BP 343 EP 357 DI 10.1016/0045-7825(92)90192-M PG 15 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA HL449 UT WOS:A1992HL44900005 ER PT J AU VILLASENOR, J BUNEMAN, O AF VILLASENOR, J BUNEMAN, O TI RIGOROUS CHARGE CONSERVATION FOR LOCAL ELECTROMAGNETIC-FIELD SOLVERS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article AB In this paper we present a rigorous method for finding the electric field in two-and-one-half and three dimensional electromagnetic plasma simulations without resorting to computationally expensive transforms. A finite grid interpretation of the divergence equation del . J = - partial derivative-rho/partial derivative t is offered which allows the current density and thus new local electric and magnetic field strengths to be determined directly from knowledge of charge motion. C1 STANFORD UNIV,DEPT ELECT ENGN,STANFORD,CA 94305. RP VILLASENOR, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 7 TC 222 Z9 228 U1 2 U2 12 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 MAR-APR PY 1992 VL 69 IS 2-3 BP 306 EP 316 DI 10.1016/0010-4655(92)90169-Y PG 11 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA HN520 UT WOS:A1992HN52000009 ER PT J AU SHIEH, LS ZHANG, JL SUNKEL, JW AF SHIEH, LS ZHANG, JL SUNKEL, JW TI A NEW APPROACH TO THE DIGITAL REDESIGN OF CONTINUOUS-TIME CONTROLLERS SO CONTROL-THEORY AND ADVANCED TECHNOLOGY LA English DT Article DE DIGITAL REDESIGN; DIGITAL CONTROL; STATE-FEEDBACK CONTROL; CASCADED CONTROL ID CONTROL-SYSTEMS; QUADRATIC REGULATORS; POLE PLACEMENT; REGION AB This paper presents a new method for digital redesign of both a continuous-time state-feedback control law and a cascaded analog controller. The concept of the Law of Mean from the integral calculus is utilized for the development of the equivalent digital controllers from the available analog controllers. A tuning parameter has been introduced into the digitally redesigned control gains so that the digitally controlled states will closely match the original continuous-time states. The proposed digital controllers give excellent performance. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV AVION SYST,HOUSTON,TX 77058. UNIV HOUSTON,COMP & SYST ENGN PROGRAM,HOUSTON,TX 77204. RP SHIEH, LS (reprint author), UNIV HOUSTON,DEPT ELECT ENGN,HOUSTON,TX 77204, USA. NR 14 TC 39 Z9 39 U1 0 U2 0 PU MITA PRESS PI TOKYO PA OCHANOMIZU CENTER BLDG 2-12 HONGO-3 BUNKYO-KU, TOKYO 113, JAPAN SN 0911-0704 J9 CONTR-THEOR ADV TECH JI Control-Theory Adv. Technol. PD MAR PY 1992 VL 8 IS 1 BP 37 EP 57 PG 21 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA HQ326 UT WOS:A1992HQ32600003 ER PT J AU BOEHLERT, GW WATSON, W SUN, LC AF BOEHLERT, GW WATSON, W SUN, LC TI HORIZONTAL AND VERTICAL DISTRIBUTIONS OF LARVAL FISHES AROUND AN ISOLATED OCEANIC ISLAND IN THE TROPICAL PACIFIC SO DEEP-SEA RESEARCH PART A-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID GREAT BARRIER-REEF; CORAL-REEF; SARGASSO SEA; LIZARD ISLAND; RECRUITMENT; PATTERNS; MASS; ICHTHYOPLANKTON; MESOZOOPLANKTON; LEPTOCEPHALI AB Ichthyoplankton and oceanographic sampling was conducted in November 1984 in waters surrounding Johnston Atoll (16-degrees-44'N, 169-degrees-32'W). a small, isolated atoll in the central Pacific Ocean. The typical flow pattern in this region is westward; the nearest island is in the Hawaiian Archipelago, 760 km away. Most collections were dominated by oceanic taxa. In the 0-50 m stratum, larval densities were relatively uniform horizontally. but densities down-current of the island tended to be higher, and fish eggs were concentrated there. In the 50-100 m stratum. larval abundance on the down-current side of the island was markedly higher than either up-current or farther down-current. Oceanic taxa did not display this pattern, while marked areas of very high abundance characterized the island-related taxa, the most abundant including the gobiid Eviota epiphanes and the apogonid Pseudamiops sp. Estimates of geostrophic flow indicate that the region down-current of the atoll was one of return flow associated with apparent mesoscale eddies or meanders north and west of the island. This region may serve as a down-current retention area for the pelagic larvae of island-related taxa and may facilitate recruitment back to the source populations. C1 NOAA, NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, LA JOLLA, CA 92038 USA. UNIV HAWAII, JOINT INST MARINE & ATMOSPHER RES, HONOLULU, HI 96822 USA. UNIV HAWAII, HAWAII INST GEOPHYS, HONOLULU, HI 96822 USA. RP NOAA, NATL MARINE FISHERIES SERV, SW FISHERIES SCI CTR, HONOLULU LAB, 2570 DOLE ST, HONOLULU, HI 96822 USA. NR 71 TC 87 Z9 92 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0198-0149 J9 DEEP-SEA RES PD MAR-APR PY 1992 VL 39 IS 3-4A BP 439 EP 466 DI 10.1016/0198-0149(92)90082-5 PG 28 WC Oceanography SC Oceanography GA HR309 UT WOS:A1992HR30900004 ER PT J AU EVANS, DL AF EVANS, DL TI GEOLOGIC PROCESS STUDIES USING SYNTHETIC APERTURE RADAR (SAR) DATA SO EPISODES LA English DT Article RP EVANS, DL (reprint author), JET PROP LAB,EARTH SCI PROGRAM,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU INT UNION GEOLOGICAL SCIENCES PI KEYWORTH PA C/O BRITISH GEOLOGICAL SURVEY, KEYWORTH, NOTTINGHAM, ENGLAND NG12 5GG SN 0705-3797 J9 EPISODES JI Episodes PD MAR PY 1992 VL 15 IS 1 BP 21 EP 31 PG 11 WC Geosciences, Multidisciplinary SC Geology GA JE445 UT WOS:A1992JE44500004 ER PT J AU CRIPPEN, RE AF CRIPPEN, RE TI MEASUREMENT OF SUBRESOLUTION TERRAIN DISPLACEMENTS USING SPOT PANCHROMATIC IMAGERY SO EPISODES LA English DT Article RP CRIPPEN, RE (reprint author), JET PROP LAB,NASA,PASADENA,CA 91109, USA. NR 0 TC 28 Z9 28 U1 1 U2 4 PU INT UNION GEOLOGICAL SCIENCES PI KEYWORTH PA C/O BRITISH GEOLOGICAL SURVEY, KEYWORTH, NOTTINGHAM, ENGLAND NG12 5GG SN 0705-3797 J9 EPISODES JI Episodes PD MAR PY 1992 VL 15 IS 1 BP 56 EP 61 PG 6 WC Geosciences, Multidisciplinary SC Geology GA JE445 UT WOS:A1992JE44500008 ER PT J AU TAGAI, T TAKEDA, H MORI, H ICHIKAWA, J TACHIBANA, R MORRISON, DA AF TAGAI, T TAKEDA, H MORI, H ICHIKAWA, J TACHIBANA, R MORRISON, DA TI CRYSTALLOGRAPHIC INVESTIGATIONS OF CALCIC PLAGIOCLASE FROM THE BAD VERMILION LAKE ANORTHOSITE COMPLEX, ONTARIO SO EUROPEAN JOURNAL OF MINERALOGY LA English DT Article DE PLAGIOCLASE; MICROSTRUCTURE; ANORTHOSITE; ARCHEAN AB The microstructures of plagioclase from the Bad Vermilion Lake Anorthosite Complex, Ontario, was investigated by means of electron probe microanalysis, X-ray diffraction and electron microscopy. The plagioclase shows the a, b, c and e-reflections in the diffraction diagram, which indicates the existence of the Huttenlocher exsolution. It was also confirmed by the transmission electron microscopy (TEM). In TEM, the antiphase boundaries (APB) were observed, where the b-APBs show partly zigzag-like forms. The characteristics of the intensity distribution of b-, c- and e-reflections and the APB form indicate that the plagioclase experienced the plutonic-like cooling rate at high temperature, a very slow cooling with more rapid cooling rate than that of metamorphic rocks in the temperature range up to 650-degrees-C and extra slow cooling to room temperature. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP TAGAI, T (reprint author), UNIV TOKYO,FAC SCI,INST MINERAL,TOKYO 113,JAPAN. NR 32 TC 0 Z9 0 U1 0 U2 0 PU E SCHWEIZERBART'SCHE VERLAGS PI STUTTGART PA NAEGELE U OBERMILLER JOHANNESSTRASSE 3A, D 70176 STUTTGART, GERMANY SN 0935-1221 J9 EUR J MINERAL JI Eur. J. Mineral. PD MAR-APR PY 1992 VL 4 IS 2 BP 299 EP 305 PG 7 WC Mineralogy SC Mineralogy GA HM502 UT WOS:A1992HM50200007 ER PT J AU GATES, TS AF GATES, TS TI EXPERIMENTAL CHARACTERIZATION OF NONLINEAR, RATE-DEPENDENT BEHAVIOR IN ADVANCED POLYMER MATRIX COMPOSITES SO EXPERIMENTAL MECHANICS LA English DT Article; Proceedings Paper CT 1991 SPRING CONF ON EXPERIMENTAL MECHANICS CY JUN 09-12, 1991 CL MILWAUKEE, WI SP SOC EXPTL MECH ID VISCOPLASTICITY AB In order to support materials selection for the next-generation supersonic civilian-passenger transport aircraft, a study has been undertaken to evaluate the material stress/strain relationships needed to describe advanced polymer matrix composites under conditions of high load and elevated temperature. As part of this effort, this paper describes the materials testing which was performed to investigate the viscoplastic behavior of graphite/thermoplastic and graphite/bismaleimide composites. Test procedures, results and data-reduction schemes which were developed for generating material constants for tension and compression loading, over a range of useful temperatures, are explained. RP GATES, TS (reprint author), NASA,LANGLEY RES CTR,MS 188E,HAMPTON,VA 23665, USA. NR 9 TC 41 Z9 41 U1 4 U2 9 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD MAR PY 1992 VL 32 IS 1 BP 68 EP 73 DI 10.1007/BF02317988 PG 6 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA HR634 UT WOS:A1992HR63400012 ER PT J AU VIKRAM, CS WITHEROW, WK AF VIKRAM, CS WITHEROW, WK TI CRITICAL NEEDS OF FRINGE-ORDER ACCURACIES IN 2-COLOR HOLOGRAPHIC-INTERFEROMETRY SO EXPERIMENTAL MECHANICS LA English DT Article AB Two-color holographic interferometry is a promising technique for separating simultaneous concentration and temperature variations in solution for crystal-growth experiments on earth and in microgravity conditions in space. The ultimate success depends on two linearly independent fringe patterns due to the different wavelengths. With available practical lasers and typical crystal-growth experimental conditions the two interference fringe patterns (other than scale effects) may not be too different. The slight error in the measured fringe order can then yield large uncertainty in temperature and concentration determination. This aspect is analytically considered for the first time in this article. A simple cell (rectangular parallelpiped) is considered containing the fluid. For simplicity, we assume a constant field along the object-wave-propagation direction in the cell. The two reconstructed fringe patterns are then represented in terms of temperature and concentration variations. Solving two equations theoretically yields the desired temperature and concentration. However, once the fringe-position measurement error is introduced, error in the temperature and concentration results, These errors are analytically determined. A particular case of TGS (triglycine sulfate) aqueous solution with HeNe (lambda = 632.8 nm) and HeCd (lambda = 441.6 nm) lasers for holography is critically discussed. It is found that a high degree of accuracy in the fringe order is required in this particular case. To improve fringe-position measurements, special techniques such as electronic phase measurement or heterodyne detection may be necessary. The study provides the analytical guidelines for designing the experiments and critical needs of desired physical parameters. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RP VIKRAM, CS (reprint author), UNIV ALABAMA,CTR APPL OPT,HUNTSVILLE,AL 35899, USA. NR 22 TC 7 Z9 7 U1 0 U2 1 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 0014-4851 J9 EXP MECH JI Exp. Mech. PD MAR PY 1992 VL 32 IS 1 BP 74 EP 77 DI 10.1007/BF02317989 PG 4 WC Materials Science, Multidisciplinary; Mechanics; Materials Science, Characterization & Testing SC Materials Science; Mechanics GA HR634 UT WOS:A1992HR63400013 ER PT J AU KELLER, LP THOMAS, KL MCKAY, DS AF KELLER, LP THOMAS, KL MCKAY, DS TI AN INTERPLANETARY DUST PARTICLE WITH LINKS TO CI CHONDRITES SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Letter ID CARBONACEOUS CHONDRITE; CARBONATES; MATRIX AB W7013F5 is a chondritic, hydrated interplanetary dust particle whose composition and mineralogy is nearly identical to that found in the CI chondrites. Transmission electron microscope observations show that the phyllosilicates in W7013F5 consist largely of a coherent intergrowth of Mg-Fe serpentine and Fe-bearing saponite on the unitcell scale. This distinctive intergrowth of phyllosilicates has only been observed previously in the CI chondrites. Other secondary minerals in W7013F5 include Mg-Fe carbonates, magnetite, and pentlandite. The mineral assemblage in W7013F5 is generally not as oxidized as that in the CI chondrites. The presence of kamacite in W7013F5 indicates that the particle is extraterrestrial, and a thin amorphous rim surrounding the particle provides evidence that it is not a piece of a meterorite that fragmented during transit through the atmosphere. The apparent lack of hydrated IDPs with CI mineralogy and chemistry may indicate that CI-type dust-producing asteroids are uncommon in the asteroid belt. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. RP KELLER, LP (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN14,HOUSTON,TX 77058, USA. NR 16 TC 30 Z9 30 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAR PY 1992 VL 56 IS 3 BP 1409 EP 1412 DI 10.1016/0016-7037(92)90072-Q PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HJ963 UT WOS:A1992HJ96300041 ER PT J AU RAU, GH TAKAHASHI, T DESMARAIS, DJ REPETA, DJ MARTIN, JH AF RAU, GH TAKAHASHI, T DESMARAIS, DJ REPETA, DJ MARTIN, JH TI THE RELATIONSHIP BETWEEN DELTA-C-13 OF ORGANIC-MATTER AND [CO2(AQ)] IN OCEAN SURFACE-WATER - DATA FROM A JGOFS SITE IN THE NORTHEAST ATLANTIC-OCEAN AND A MODEL SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Letter ID CARBON ISOTOPE FRACTIONATION; STABLE CARBON; MARINE-PHYTOPLANKTON; C-13; CO2; DIOXIDE; PHOTOSYNTHESIS; DISCRIMINATION; DEPLETION; PACIFIC AB The delta-C-13 of suspended particulate organic matter (SPOM) in surface waters increased from -22.9 to -18.1 parts per thousand during April 25-May 31, 1989 at the JGOFS North Atlantic Bloom Experiment Site (NABE Site; 47-degrees-N, 20-degrees-W). During the same period, nearly parallel increases in sinking POM-delta-C-13 were also found, although these values were usually lower than those of the corresponding SPOM. Consistent with the hypothesis that plankton-delta-C-13 and [CO2(aq)] are inversely related, the increases in both sinking and suspended POM-delta-C-13 were highly negatively correlated with mixed-layer [CO2(aq)] that generally decreased from 13.2-10.1-mu-moles/kg during the five weeks. The change in SPOM-delta-C-13 per change in [CO2(aq)], however, appears to be somewhat greater than that expected from previous, though less direct, ocean and laboratory evidence. By adapting a model of plant delta-C-13 by FARQUHAR et al. (1982), it is shown that under a constant phytoplankton demand for CO2 an inverse, nonlinear SPOM-delta-C-13 response to ambient [CO2(aq)] is expected. Such trends are unlike the negative linear relationships indicated by data from the NABE Site and or from Southern Hemisphere waters. Such differences between predicted and observed SPOM-delta-C-13 vs. [CO2(aq)] trends and among observed relationships can be reconciled, however, if biological CO2 demand is allowed to vary. This has significant implications for the use of the delta-C-13 of plankton (or their organic subfractions or sedimentary remains) as a proxy for past or present ocean CO2 concentrations and biological productivity. C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. WOODS HOLE OCEANOG INST,WOODS HOLE,MA 02543. MOSS LANDING MARINE LABS,MOSS LANDING,CA 95039. RP RAU, GH (reprint author), UNIV CALIF SANTA CRUZ,INST MARINE SCI,SANTA CRUZ,CA 95064, USA. FU NCIPC CDC HHS [OCE-8816280, OCE-9012172, OCE-9017773] NR 42 TC 210 Z9 219 U1 2 U2 30 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 MAR PY 1992 VL 56 IS 3 BP 1413 EP 1419 DI 10.1016/0016-7037(92)90073-R PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HJ963 UT WOS:A1992HJ96300042 PM 11537204 ER PT J AU RASOOL, SI AF RASOOL, SI TI GLOBAL ENVIRONMENTAL-CHANGE - SPACE OBSERVATION AND MONITORING SO GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS LA English DT Editorial Material RP RASOOL, SI (reprint author), NASA,INT GEOSPHERE BIOSPHERE PROGRAM,DATA & INFORMAT SYST,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 0959-3780 J9 GLOBAL ENVIRON CHANG JI Glob. Environ. Change-Human Policy Dimens. PD MAR PY 1992 VL 2 IS 1 BP 64 EP 65 PG 2 WC Environmental Sciences; Environmental Studies; Geography SC Environmental Sciences & Ecology; Geography GA HM405 UT WOS:A1992HM40500010 ER PT J AU BORUCKI, WJ MAGALHAES, JA AF BORUCKI, WJ MAGALHAES, JA TI ANALYSIS OF VOYAGER 2 IMAGES OF JOVIAN LIGHTNING SO ICARUS LA English DT Article ID MOIST CONVECTION; INTERNAL HEAT; JUPITER; WATER; ATMOSPHERE; FLOW; ABUNDANCE; SATURN; SYSTEM; CLOUD RP BORUCKI, WJ (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 35 TC 32 Z9 32 U1 2 U2 3 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 MAR PY 1992 VL 96 IS 1 BP 1 EP 14 DI 10.1016/0019-1035(92)90002-O PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM499 UT WOS:A1992HM49900001 ER PT J AU MOSSER, B GAUTIER, D KOSTIUK, T AF MOSSER, B GAUTIER, D KOSTIUK, T TI ON THE DETECTABILITY OF JOVIAN OSCILLATIONS WITH INFRARED HETERODYNE MEASUREMENTS SO ICARUS LA English DT Article ID JUPITER; SPECTROSCOPY; MODE; SPECTROMETER; SPECTRUM; LASER; HELIOSEISMOLOGY; TRANSITIONS; SEISMOLOGY; HYDROGEN C1 NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,GREENBELT,MD 20771. RP MOSSER, B (reprint author), DESPA,OBSERV PARIS MEUDON 5,PL JULES JANSSEN,F-92195 MEUDON,FRANCE. RI Kostiuk, Theodor/A-3077-2014 NR 56 TC 14 Z9 14 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 MAR PY 1992 VL 96 IS 1 BP 15 EP 26 DI 10.1016/0019-1035(92)90003-P PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM499 UT WOS:A1992HM49900002 ER PT J AU SPRAGUE, AL KOZLOWSKI, RWH HUNTEN, DM WELLS, WK GROSSE, FA AF SPRAGUE, AL KOZLOWSKI, RWH HUNTEN, DM WELLS, WK GROSSE, FA TI THE SODIUM AND POTASSIUM ATMOSPHERE OF THE MOON AND ITS INTERACTION WITH THE SURFACE SO ICARUS LA English DT Article ID TENUOUS LUNAR ATMOSPHERE; MERCURY; EXOSPHERE; DISCOVERY C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. SUSQUEHANNA UNIV,SELINSGROVE,PA 17870. RP SPRAGUE, AL (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 43 TC 77 Z9 77 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 1992 VL 96 IS 1 BP 27 EP 42 DI 10.1016/0019-1035(92)90004-Q PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HM499 UT WOS:A1992HM49900003 ER PT J AU HERRING, GC HILLARD, ME AF HERRING, GC HILLARD, ME TI NOISE AMPLITUDE MEASUREMENTS OF SINGLE-MODE CW LASERS AT RADIO FREQUENCIES SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Letter ID SPECTROSCOPY; LINES AB This letter presents the results of noise measurements for a variety of single-longitudinal-mode CW lasers (Ar+, standing-wave-dye, and ring-dye) that are commercially available. A quantitative comparison of the total output power fluctuations detected over the 7-300 MHz region (3 dB points) is presented. RP HERRING, GC (reprint author), NASA,LANGLEY RES CTR,DIV INSTRUMENT RES,HAMPTON,VA 23665, USA. NR 9 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 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAR PY 1992 VL 28 IS 3 BP 570 EP 572 DI 10.1109/3.124978 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA HG906 UT WOS:A1992HG90600001 ER PT J AU EPP, LW CHAN, CH MITTRA, R AF EPP, LW CHAN, CH MITTRA, R TI PERIODIC STRUCTURES WITH TIME-VARYING LOADS SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID FREQUENCY-SELECTIVE SURFACES AB The loading of a periodic surface with time-varying negative resistance diodes is discussed. The method predicts the transmitted and reflected power at the source frequency and the harmonic frequencies generated by the time-varying devices. The analysis uses an equivalent circuit representation at the load location in the unit cell, which is derived from the moment method solution of the periodic problem. It is therefore applicable to all angles of incidence, arbitrarily shaped surfaces, arbitrarily placed loading, lossy conductors, and surfaces supported by dielectric layers. C1 UNIV WASHINGTON,DEPT ELECT ENGN,ELECTROMAGNET & REMOTE SENSING LAB,SEATTLE,WA 98195. UNIV ILLINOIS,DEPT ELECT & COMP ENGN,ELECTROMAGNET COMMUN LAB,URBANA,IL 61801. RP EPP, LW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 12 TC 6 Z9 6 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 MAR PY 1992 VL 40 IS 3 BP 251 EP 256 DI 10.1109/8.135465 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HP427 UT WOS:A1992HP42700002 ER PT J AU WEN, JT AF WEN, JT TI STABILITY OF A CLASS OF INTERCONNECTED EVOLUTION SYSTEMS SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Note ID HILBERT-SPACES; EXACT CONTROLLABILITY; EQUATIONS AB Stability conditions for a class of interconnected systems modeled by linear abstract evolution equations and a memoryless nonlinearity are derived. These conditions are stated in terms of the passivity of each of the subsystems and can be considered as a partial generalization of the hyperstability theorem. A Lyapunov function approach is used in the proof without requiring the positive definiteness of the Lyapunov function. Application to the robustness analysis of the infinite-dimensional linear quadratic regulator is also discussed. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP WEN, JT (reprint author), RENSSELAER POLYTECH INST,DEPT ELECT COMP & SYST ENGN,TROY,NY 12181, USA. RI Wen, John/B-4474-2008 OI Wen, John/0000-0002-5123-5411 NR 29 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD MAR PY 1992 VL 37 IS 3 BP 342 EP 347 DI 10.1109/9.119633 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA HE802 UT WOS:A1992HE80200005 ER PT J AU MILEANT, A HINEDI, S AF MILEANT, A HINEDI, S TI LOCK DETECTION IN COSTAS LOOPS SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Letter AB Previous analyses of lock detector algorithms for Costas loops have ignored the effects of the inherent correlation between samples of the phase error process. In this paper, both analysis and simulations are used to quantify the effects of phase correlation on lock detection for the "square law" and "absolute value" type detectors. Results are obtained which depict the lock detection probability as a function of loop signal-to-noise ratio for a given false alarm rate. It is shown that the square law detector experiences less degradation due to phase jitter than the absolute value detector and that the degradation in detector signal-to-noise ratio is more pronounced for squarewave than for sinewave signals. RP MILEANT, A (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 3 TC 5 Z9 5 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD MAR PY 1992 VL 40 IS 3 BP 480 EP 483 DI 10.1109/26.135716 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HR454 UT WOS:A1992HR45400006 ER PT J AU VILNROTTER, VA RODEMICH, ER DOLINAR, SJ AF VILNROTTER, VA RODEMICH, ER DOLINAR, SJ TI REAL-TIME COMBINING OF RESIDUAL CARRIER ARRAY SIGNALS USING ML WEIGHT ESTIMATES SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article AB A real-time digital signal combining system for use with array feeds is proposed. The combining system attempts to compensate for signal-to-noise ratio (SNR) loss resulting from antenna deformations induced by gravitational and atmospheric effects. The combining weights are obtained directly from the observed residual carrier samples in each channel using a "sliding-window" implementation of a maximum-likelihood (ML) parameter estimator. It is shown that with averaging times of about 0.1 s, combining loss for a seven-element array can be limited to about 0.1 dB in a realistic operational environment. This result suggests that the real-time combining system proposed here is capable of recovering virtually all of the signal power captured by the array feed, even in the presence of severe wind gusts and similar disturbances. RP VILNROTTER, VA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 8 TC 9 Z9 17 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD MAR PY 1992 VL 40 IS 3 BP 604 EP 615 DI 10.1109/26.135731 PG 12 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HR454 UT WOS:A1992HR45400021 ER PT J AU TRUONG, TK SHIH, MT REED, IS SATORIUS, EH AF TRUONG, TK SHIH, MT REED, IS SATORIUS, EH TI A VLSI DESIGN FOR A TRACE-BACK VITERBI DECODER SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article AB A systolic Viterbi decoder for convolutional codes is developed which uses the trace-back method to reduce the amount of data needed to be stored in registers. It is shown that this new algorithm requires a smaller chip size and achieves a faster decoding time than other existing methods. C1 MEM HOSP,DEPT RADIOL,LONG BEACH,CA. UNIV SO CALIF,DEPT ELECT ENGN,LOS ANGELES,CA 90089. RP TRUONG, TK (reprint author), CALTECH,JET PROP LAB,COMMUN SYST RES SECT,TECH STAFF,PASADENA,CA 91109, USA. NR 6 TC 31 Z9 33 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD MAR PY 1992 VL 40 IS 3 BP 616 EP 634 DI 10.1109/26.135732 PG 19 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HR454 UT WOS:A1992HR45400022 ER PT J AU HOLBEN, B VERMOTE, E KAUFMAN, YJ TANRE, D KALB, V AF HOLBEN, B VERMOTE, E KAUFMAN, YJ TANRE, D KALB, V TI AEROSOL RETRIEVAL OVER LAND FROM AVHRR DATA - APPLICATION FOR ATMOSPHERIC CORRECTION SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SCALE AIR-POLLUTION; SATELLITE MEASUREMENTS; DISTRIBUTIONS; RED AB Correction of AVHRR imagery for the aerosol effect requires retrieval of the aerosol loading from the images. In this paper two retrieval algorithms that were previously developed for Landsat are modified for the AVHRR. The methods which determine the aerosol optical thickness over land surfaces from AVHRR band 1 data independent of ancillary information are described. The first method retrieves aerosols based on the atmospheric effect on the path radiance. This method requires the surface reflectance to be 0.02 +/- 0.01, which is found over forests in the red channel. Two techniques are used to screen an AVHRR scene for pixels that have this low reflectance. One is based on selecting the lowest NDVI or by selecting the minimum 3.75-mu-m radiance. The qualifying requirements for these techniques are discussed and the method demonstrated to retrieve aerosol optical thicknesses to approximately +/- 0.1. The second method uses the change in contrast for several scenes to determine the change in the optical thickness between the scenes. A reference scene allows absolute determination. The method has an rms error of approximately 0.1. The two methods are discussed with respect to other methods as well as their implications for global scale aerosol monitoring and atmospheric correction. C1 UNIV MARYLAND,COLLEGE PK,MD 20742. RP HOLBEN, B (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771, USA. RI Kalb, Virginia/A-9971-2009; Vermote, Eric/K-3733-2012 OI Kalb, Virginia/0000-0002-3107-9271; NR 34 TC 129 Z9 139 U1 6 U2 15 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 MAR PY 1992 VL 30 IS 2 BP 212 EP 222 DI 10.1109/36.134072 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200003 ER PT J AU MARTONCHIK, JV DINER, DJ AF MARTONCHIK, JV DINER, DJ TI RETRIEVAL OF AEROSOL OPTICAL-PROPERTIES FROM MULTI-ANGLE SATELLITE IMAGERY SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID ATMOSPHERIC TRANSFER; VEGETATION CANOPIES; PHYSICAL MODEL; REFLECTANCE; SCATTERING; RADIATION AB Optical properties of tropospheric aerosols, such as their opacity, single-scattering albedo, and phase function are needed for studies of their effects on the solar radiation budget at the Earth's surface and as input to surface reflectance retrieval algorithms designed to correct top-of-atmosphere imagery for atmospheric effects. Using simulation multi-angle imagery, we have been investigating a new method for retrieving atmospheric aerosol optical properties over land. The described method makes use of the presence of spatial contrasts within the imagery, and compares the spatial Fourier transforms of the multi-angle images at zero and nonzero spatial frequencies. An initial guess for the aerosol properties is made and the Fourier components of the surface reflectance distribution are retrieved at zero and nonzero frequencies. A comparison of the angular shape of the retrieved functions is then used to establish whether the initial guess for the aerosol parameters was correct. Other than the need to define a relationship between the angular variation of the Fourier transform of the intrinsic surface angular reflectance at the zero and nonzero frequencies, the method assumes no a priori knowledge about the aerosols or surface characteristics. We discuss sensitivities to various aerosol properties. C1 CALTECH,JET PROP LAB,REMOTE SENSING SCI PROGRAM,PASADENA,CA 91109. RP MARTONCHIK, JV (reprint author), CALTECH,JET PROP LAB,ATMOSPHER & COMETARY SCI SECT,PASADENA,CA 91109, USA. NR 15 TC 45 Z9 50 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 MAR PY 1992 VL 30 IS 2 BP 223 EP 230 DI 10.1109/36.134073 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 HP272 UT WOS:A1992HP27200004 ER PT J AU TANRE, D HOLBEN, BN KAUFMAN, YJ AF TANRE, D HOLBEN, BN KAUFMAN, YJ TI ATMOSPHERIC CORRECTION ALGORITHM FOR NOAA-AVHRR PRODUCTS - THEORY AND APPLICATION SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID AEROSOL OPTICAL-THICKNESS; SPACE MEASUREMENTS; PRECIPITABLE WATER; SATELLITE IMAGERY; VEGETATION INDEX; REFLECTANCE; DISTRIBUTIONS; RADIATION; TURBIDITY; CANOPY AB Investigation of the effect of atmospheric constituents on NOAA Advanced Very High Resolution Radiometer (AVHRR) visible and near-infrared data is presented. Part A describes the general remote sensing equation including scattering, absorption and bidirectional reflectance (BRDF) effects for the AVHRR solar bands. Part B specifically addresses the magnitude of the atmospheric effects for AVHRR solar bands with respect to their impact on the normalized difference vegetation index (NDVI) and the surface BRDF. Part C addresses possible approaches for acquiring atmospheric informations and illustrates examples of atmospheric correction of surface reflectance and NDVI. Invariant effects (ozone absorption and molecular scattering) and variant effects (water vapor absorption and aerosol scattering) are shown to dominate the atmospheric effects in the AVHRR solar bands. Because these components are a function of viewing and illumination geometry, their effects are highly variable and at times compensating. Decoupling the various components is shown to be appropriate allowing selective correction. Water vapor absorption is of major importance, affecting the apparent reflectance in the near IR by reducing it by 10-30%, depending on the amount of water vapor and the direction of illumination and observation. Ozone absorption can reduce the apparent reflectance in channel 1 by 5-15%. Molecular scattering can increase the apparent reflectance in channel 1 by DELTA(rho) = 0.02-0.07 depending on the direction of illumination and observation. In the red channel (channel 1) the effect of moderate haze is of the same magnitude as the reflectance of vegetated surfaces and the effect of dense haze, dust outbreaks, or smoke episodes can mask completely the surface properties. Molecular scattering can be easily corrected and should be a priority; ozone absorption, although less important, can be easily corrected also. Correction for water vapor absorption should also be made a priority for sparsely vegetated areas due to the large diurnal variations in content. The aerosol effect is highly variable as a function of location and time and, consequently, the required inputs are often unavailable. Its correction is important for derivation of absolute radiances and to correct the NDVI for densely vegetated areas. It can suppress the value of the true NDVI by 0.10. RP TANRE, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. NR 67 TC 171 Z9 182 U1 0 U2 4 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 MAR PY 1992 VL 30 IS 2 BP 231 EP 248 DI 10.1109/36.134074 PG 18 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200005 ER PT J AU IRONS, JR CAMPBELL, GS NORMAN, JM GRAHAM, DW KOVALICK, WM AF IRONS, JR CAMPBELL, GS NORMAN, JM GRAHAM, DW KOVALICK, WM TI PREDICTION AND MEASUREMENT OF SOIL BIDIRECTIONAL REFLECTANCE SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID NEAR-INFRARED RANGE; SPECTRAL RESPONSE; BARE SOIL; SURFACES; CANOPIES; MODEL; SPECTROSCOPY; ANISOTROPY; ROUGHNESS; EQUATION AB A model for soil bidirectional reflectance distribution functions (BRDF's) in visible and reflective infrared wavelengths is introduced and compared to data acquired in the field. The model is based on the representation of soil surfaces by a collection of opaque spheres sitting on a Lambertian horizontal surface. Soil reflectance is expressed as a function of the horizontal area obscured by a sphere, the amount of surface in shadow, the relative brightness of a sphere, and the fraction of diffuse illumination. These terms are expressed as functions of the view direction, solar direction, and a sphere area index. The model is not sensitive to increases in the sphere area index beyond a value of 0.4. For comparison, soil reflectance factor data were acquired on a tilled field from many view directions and for a range of solar directions. The observed reflectance factor distributions were consistent with those predicted by the function; maximum reflectance occurred in the antisolar direction and reflectance decreased with increasing phase angle. Increasing the surface roughness by different tillage methods did not substantially alter the directional anisotropy of the soil reflectance factors. The model was fit to the data by a nonlinear least squares procedure. The relative rms difference between the predicted and observed reflectance factors was typically less than 15% when the solar zenith angle was less than 50-degrees. The model provided a realistic representation of tilled field reflectance distributions. RP IRONS, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,CODE 923,GREENBELT,MD 20771, USA. RI Irons, James/D-8535-2012 NR 39 TC 56 Z9 67 U1 2 U2 11 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 MAR PY 1992 VL 30 IS 2 BP 249 EP 260 DI 10.1109/36.134075 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200006 ER PT J AU KAUFMAN, YJ TANRE, D AF KAUFMAN, YJ TANRE, D TI ATMOSPHERICALLY RESISTANT VEGETATION INDEX (ARVI) FOR EOS-MODIS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID SATELLITE MEASUREMENTS; AIR-POLLUTION; AVHRR; SAHEL AB Atmospherically resistant vegetation index (ARVI) is proposed and developed to be used for remote sensing of vegetation from the Earth Observing System (EOS) MODIS sensor. The same index can be used for remote sensing from Landsat TM, and the EOS-HIRIS sensor. The index takes advantage of the presence of the blue channel (0.47 +/- 0.01-mu-m) in the MODIS sensor, in addition to the red (0.66 +/- 0.025-mu-m) and the near IR (0.865 +/- 0.02-mu-m) channels that compose the present normalized difference vegetation index (NDVI). The resistance of the ARVI to atmospheric effects (in comparison to the NDVI) is accomplished by a self-correction process for the atmospheric effect on the red channel, using the difference in the radiance between the blue and the red channels to correct the radiance in the red channel. Simulations using radiative transfer computations on arithmetic and natural surface spectra, for various atmospheric conditions, show that ARVI has a similar dynamic range to the NDVI, but is, on average, four times less sensitive to atmospheric effects than the NDVI. The improvement is much better for vegetated surfaces than for soils. It is much better for moderate to small size aerosol particles (e.g., continental, urban, or smoke aerosol) than for large particle size (e.g., maritime aerosol or dust). Due to a fortunate coincidence, the same optimal value of the parameter-gamma that defines the weighting of the blue band radiance in the ARVI definition, is found for vegetated areas with small to moderate aerosol particle size (e.g., anthropogenic aerosol and smoke) and for arid regions with large particle size (e.g., dust). Therefore, a single combination of the blue and the red channels in the ARVI may be used in all or most remote sensing applications. Due to the excellent atmospheric resistance of the ARVI, it is expected that remote sensing from MODIS of the vegetation index over most land surfaces will include molecular and ozone correction with no further need for aerosol correction, except for dust conditions, like in the Sahel. RP KAUFMAN, YJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771, USA. NR 44 TC 370 Z9 442 U1 12 U2 61 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 MAR PY 1992 VL 30 IS 2 BP 261 EP 270 DI 10.1109/36.134076 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200007 ER PT J AU MYNENI, RB ASRAR, G TANRE, D CHOUDHURY, BJ AF MYNENI, RB ASRAR, G TANRE, D CHOUDHURY, BJ TI REMOTE-SENSING OF SOLAR-RADIATION ABSORBED AND REFLECTED BY VEGETATED LAND SURFACES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB The problem of remotely sensing the amount of solar radiation absorbed and reflected by vegetated land surfaces was investigated with the aid of one-and three-dimensional radiative transfer models. Desert-like vegetation was modeled as clumps of leaves randomly distributed on a bright dry soil with a ground cover of generally less than 100%. Surface albedo (ALB), fraction of photosynthetically active radiation absorbed by the canopy (FAPAR), fractions of solar radiation absorbed by the canopy (FASOLAR) and soil (FASOIL), and normalized difference vegetation index (NDVI) were calculated for various illumination conditions. A base case was defined with problem parameters considered typical for desert vegetation in order to understand the dynamics of NDVI and ALB with respect to ground cover, leaf area index, soil brightness, and illumination conditions. The magnitude of errors involved in the estimation of surface albedo from broad-band monodirectional measurements was assessed through model simulations of SPOT, AVHRR, and GOES sensors. The nature of the relationships between NDVI vs. FASOLAR, FAPAR, FASOIL, and ALB, and their sensitivity to all problem parameters was investigated in order to develop simple predictive models. Finally, the relationship between NDVI measured above the atmosphere to that above the canopy at the ground surface was studied to characterize atmospheric effects in the remote sensing problem. C1 NASA,WASHINGTON,DC 20546. NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771. UNIV SCI & TECHNOL LILLE,ATMOSPHER OPT LAB,VILLENEUVE DASEQ,FRANCE. RP MYNENI, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771, USA. RI Myneni, Ranga/F-5129-2012 NR 26 TC 43 Z9 43 U1 1 U2 10 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 MAR PY 1992 VL 30 IS 2 BP 302 EP 314 DI 10.1109/36.134080 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 HP272 UT WOS:A1992HP27200011 ER PT J AU KIMES, DS HARRISON, PR HARRISON, PA AF KIMES, DS HARRISON, PR HARRISON, PA TI LEARNING CLASS DESCRIPTIONS FROM A DATA-BASE OF SPECTRAL REFLECTANCE WITH MULTIPLE VIEW ANGLES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID DIRECTIONAL REFLECTANCE; VEGETATION CANOPIES; FACTOR DISTRIBUTIONS AB A program was developed to learn class descriptions from positive and negative training examples of spectral, directional reflectance data taken from natural surfaces such as bare soil, natural vegetation, or agricultural vegetation. The learning program combined a form of learning referred to as learning by example with the generate and test paradigm to provide a robust learning environment that could handle error prone data. The learning program was tested by having it learn class descriptions of various categories of percent ground cover and plant height. These class descriptions were then used to classify an array of targets. The class descriptions in this program were comprised of a series of different relationships between combinations of directional view angles, e.g., (30 50), (45 60), (10 180), etc. where the values in parentheses are the zenith and relative azimuth view angles for a particular view. The program found the sequence of relationships that contained the most important information that distinguished the classes. The concept being learned was a sequence of relationships that optimized the discrimination of a class. A relationship or "instance," as defined in this paper, can be any user-defined directional spectral relationship. In this paper the possible relationships (instances) included in a class description were greater than relationships in terms of reflectance between all possible combinations of two view angles (e.g., greater than (60 180), (40 0)), first maximum, second maximum, first minimum, and second minimum relationships for each possible view angle (e.g., first-max (15 135)). In theory, the user could define any class they wish. This could include a broad category such as soil or vegetation. It could also include more specific classes such as corn, soybeans, or wheat. It might also include subclasses based on discrete breakdowns of continuous parameters. For example, ground cover could be divided into the categories; sparse (0-30% ground cover), intermediate (30-60% ground cover), and dense (60-100% ground cover). Structurally related classes such as homogeneous and nonhomogeneous vegetation canopies might also be used. Other class concepts might include things such as species, biomass, leaf area index, physical location, vegetation structure, or portion green leaf material or solar zenith angle. The learning program used Artificial Intelligence techniques that automate a very tedious process that would traditionally require an expert to iterate the process for every combination of solar zenith angle, class, and sensor system used. C1 USN ACAD,ANNAPOLIS,MD 21402. JJM SYST INC,ANNAPOLIS,MD 21401. RP KIMES, DS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EARTH RESOURCES BRANCH,GREENBELT,MD 20771, USA. NR 21 TC 4 Z9 4 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 MAR PY 1992 VL 30 IS 2 BP 315 EP 325 DI 10.1109/36.134081 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200012 ER PT J AU DEERING, DW ECK, TF GRIER, T AF DEERING, DW ECK, TF GRIER, T TI SHINNERY OAK BIDIRECTIONAL REFLECTANCE PROPERTIES AND CANOPY MODEL INVERSION SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID INHOMOGENEOUS VEGETATION CANOPIES; LEAF-AREA INDEX; PLANT CANOPY; PARAMETERS; DISTRIBUTIONS; IRRADIANCE; RADIANCE; ALBEDO; SOIL; SKY AB The fact that most plant communities exhibit anisotropic reflectance properties is currently well recognized. However, the nature of such reflectances and the diural and seasonal variations of bidirectional reflectance for natural plant communities are not well understood. Plant canopy models are being developed which will enable us to utilize this anisotropic property of vegetation to extract important plant information from remote sensing measurements. This paper presents field measurements and the results of a three-dimensional canopy model inversion for sand shinnery oak. Spectral bidirectional radiance measurements in three spectral channels, 0.65-0.67-mu-m, 0.81-0.84-mu-m, and 1.62-1.69-mu-m, encompassing both the complete land surface and sky hemispheres were acquired for a sand shinnery oak plant community in West Texas. The changes in canopy reflectance that occur with variations in solar zenith angle and view direction and for two seasons of the year were evaluated. A Three-dimensional Radiation Interaction Model (TRIM) was then inverted to estimate oak leaf area index (LAI) and canopy density, expressed as percentage cover, from the bidirectional reflectance data. C1 HUGHES STX CORP,LANHAM,MD 20706. SUNY BINGHAMTON,DEPT SYST SCI,BINGHAMTON,NY 13901. RP DEERING, DW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH 923,GREENBELT,MD 20771, USA. RI ECK, THOMAS/D-7407-2012 NR 31 TC 39 Z9 44 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 MAR PY 1992 VL 30 IS 2 BP 339 EP 348 DI 10.1109/36.134083 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA HP272 UT WOS:A1992HP27200014 ER PT J AU EVANS, DL FARR, TG VANZYL, JJ AF EVANS, DL FARR, TG VANZYL, JJ TI ESTIMATES OF SURFACE-ROUGHNESS DERIVED FROM SYNTHETIC APERTURE RADAR (SAR) DATA SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID CIMA VOLCANIC FIELD; EASTERN MOJAVE DESERT; BASALTIC LAVA FLOWS; LANDSCAPE EVOLUTION; CALIFORNIA; IMAGES; POLARIMETRY; TOPOGRAPHY; ARIZONA; NEVADA AB Radar remote sensing data provide a unique perspective of the Earth's crust and the processes that have influenced its evolution. Physically based models are required, however, to relate the geophysical quantities being measured by the radar sensor to useful geologic information. In this study, synthetic aperture radar (SAR) data over the Cima volcanic field in the Mojave Desert of California are quantitatively connected with microtopography through inversion of a radar backscatter model. Changes in surface roughness inferred from the derived microtopography are modeled and found to be consistent with aeolian mantling as surfaces age. Estimated rates of aeolian deposition for the Cima area are compared to the Lunar Crater volcanic field in Nevada. Rates of deposition appear to be higher at Cima volcanic field, most likely because of its proximity to Soda Lake, the main source of the aeolian material. RP EVANS, DL (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. OI Farr, Thomas/0000-0001-5406-2096 NR 35 TC 40 Z9 42 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1992 VL 30 IS 2 BP 382 EP 389 DI 10.1109/36.134087 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 HP272 UT WOS:A1992HP27200018 ER PT J AU SIMONCELLI, EP FREEMAN, WT ADELSON, EH HEEGER, DJ AF SIMONCELLI, EP FREEMAN, WT ADELSON, EH HEEGER, DJ TI SHIFTABLE MULTISCALE TRANSFORMS SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE WAVELET, MULTISCALE; PYRAMID; ALIASING; SAMPLING; INTERPOLATION; ORIENTATION; STEERABLE FILTERS; IMAGE REPRESENTATION; IMAGE PROCESSING ID IMAGES; WAVELETS; ALGORITHMS; FREQUENCY; FILTERS AB Orthogonal wavelet transforms have recently become a popular representation for multiscale signal and image analysis. One of the major drawbacks of these representations is their lack of translation invariance: the content of wavelet subbands is unstable under translations of the input signal. Wavelet transforms are also unstable with respect to dilations of the input signal, and in two dimensions, rotations of the input signal. We formalize these problems by defining a type of translation invariance that we call "shiftability". In the spatial domain, shiftability corresponds to a lack of aliasing; thus, the conditions under which the property holds are specified by the sampling theorem. Shiftability may also be considered in the context of other domains, particularly orientation and scale. "Jointly shiftable" transforms that are simultaneously shiftable in more than one domain are explored. Two examples of jointly shiftable transforms are designed and implemented: a one-dimensional transform that is jointly shiftable in position and scale, and a two-dimensional transform that is jointly shiftable in position and orientation. The usefulness of these image representations for scale-space analysis, stereo disparity measurement, and image enhancement is demonstrated. C1 MIT,DEPT ELECT ENGN & COMP SCI,CAMBRIDGE,MA 02139. MIT,DEPT BRAIN & COGNITIVE SCI,CAMBRIDGE,MA 02139. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. STANFORD UNIV,DEPT PSYCHOL,STANFORD,CA 94305. RP SIMONCELLI, EP (reprint author), MIT,MEDIA LAB,CAMBRIDGE,MA 02139, USA. NR 50 TC 751 Z9 796 U1 4 U2 40 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAR PY 1992 VL 38 IS 2 BP 587 EP 607 DI 10.1109/18.119725 PN 2 PG 21 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA HG008 UT WOS:A1992HG00800005 ER PT J AU TAYLOR, RN LEVINE, DL KELLY, CD AF TAYLOR, RN LEVINE, DL KELLY, CD TI STRUCTURAL TESTING OF CONCURRENT PROGRAMS SO IEEE TRANSACTIONS ON SOFTWARE ENGINEERING LA English DT Article DE CONCURRENCY; COVERAGE CRITERIA; STRUCTURAL TESTING; TESTING CRITERIA HIERARCHY AB Although structural testing techniques are among the weakest available with regard to developing confidence in sequential programs, they are not without merit. This paper extends the notion of structural testing criteria to concurrent programs and proposes a hierarchy of supporting structural testing techniques. Coverage criteria described include concurrency state coverage, state transition coverage, and synchronization coverage. Requisite support tools include a static concurrency analyzer and either a program transformation system or a powerful run-time monitor. Also helpful is a controllable run-time scheduler. The techniques proposed are suitable for Ada or CSP-like languages. Best results are obtained for programs having only static naming of tasking objects. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP TAYLOR, RN (reprint author), UNIV CALIF IRVINE,DEPT INFORMAT & COMP SCI,IRVINE,CA 92717, USA. NR 26 TC 79 Z9 84 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 SN 0098-5589 J9 IEEE T SOFTWARE ENG JI IEEE Trans. Softw. Eng. PD MAR PY 1992 VL 18 IS 3 BP 206 EP 215 DI 10.1109/32.126769 PG 10 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA HK190 UT WOS:A1992HK19000003 ER PT J AU GERTLER, JJ ANDERSON, KC AF GERTLER, JJ ANDERSON, KC TI AN EVIDENTIAL REASONING EXTENSION TO QUANTITATIVE MODEL-BASED FAILURE DIAGNOSIS SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS LA English DT Article ID FAULT-DIAGNOSIS; DYNAMIC-SYSTEMS; REDUNDANCY; KNOWLEDGE; DESIGN AB The detection and diagnosis of failures in physical systems characterized by continuous-time operation is studied. A quantitative diagnostic methodology has been developed that utilizes the mathematical model of the physical system. On the basis of the latter, diagnostic models are derived that each comprise a set of orthogonal parity equations. To improve the robustness of the algorithm, several models may be used in parallel, providing potentially incomplete and/or conflicting inferences. Dempster's rule of combination is used to integrate evidence from the different models. The basic probability measures are assigned utilizing quantitative information extracted from the mathematical model and from on-line computations performed therewith. C1 NASA,GODDARD SPACE FLIGHT CTR,CLIFTON,VA 22024. RP GERTLER, JJ (reprint author), GEORGE MASON UNIV,DEPT ELECT ENGN,FAIRFAX,VA 22030, USA. NR 27 TC 23 Z9 24 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 0018-9472 J9 IEEE T SYST MAN CYB JI IEEE Trans. Syst. Man Cybern. PD MAR-APR PY 1992 VL 22 IS 2 BP 275 EP 289 DI 10.1109/21.148430 PG 15 WC Computer Science, Cybernetics; Engineering, Electrical & Electronic SC Computer Science; Engineering GA JF034 UT WOS:A1992JF03400006 ER PT J AU SRIDHAR, B PHATAK, AV AF SRIDHAR, B PHATAK, AV TI ANALYSIS OF IMAGE-BASED NAVIGATION SYSTEM FOR ROTOCRAFT LOW-ALTITUDE FLIGHT SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS LA English DT Article ID OBJECTS AB Human pilots can fly at low-altitude and in the nap-of-the-Earth mode because of their ability to process visual information, locate obstacles and modify their flight profile as necessary to follow a desired course. Therefore, an essential step in the automation of rotorcraft low-altitude flight is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. The paper examines some of the issues in the location of objects using a sequence of images from a passive sensor. Simulation results are presented to show how object location is affected by the choice of the Kalman filter estimation technique, errors in the measurement of rotorcraft motion parameters, and errors in camera calibration. C1 ANALYT MECH ASSOCIATES,MT VIEW,CA 94043. RP SRIDHAR, B (reprint author), NASA,AMES RES CTR,MAIL STOP 210-9,MOFFETT FIELD,CA 94035, USA. NR 9 TC 11 Z9 13 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 0018-9472 J9 IEEE T SYST MAN CYB JI IEEE Trans. Syst. Man Cybern. PD MAR-APR PY 1992 VL 22 IS 2 BP 290 EP 299 DI 10.1109/21.148431 PG 10 WC Computer Science, Cybernetics; Engineering, Electrical & Electronic SC Computer Science; Engineering GA JF034 UT WOS:A1992JF03400007 ER PT J AU DAVIDSON, F AF DAVIDSON, F TI LARGE-SCALE PROJECTS - PLANETWIDE COALITIONS NEEDED SO INTERDISCIPLINARY SCIENCE REVIEWS LA English DT Article AB Taking the Channel Tunnel as an example, there is a need for hard cost-benefit estimates to be made before any large scale project is begun. Long periods of gestation are frequent, high tech is not limited to macrosystems and structured collaboration between governments and other institutions is essential for success. The PAT system, supersonic tube flight and the priority selection of macroprojects are discussed and the establishment of a prototype development group is recommended. C1 NASA,GODDARD SPACE FLIGHT CTR,EXPLORAT TASK FORCE,GREENBELT,MD 20771. MIT,MACROENGN RES GRP,CAMBRIDGE,MA 02139. NR 14 TC 0 Z9 0 U1 0 U2 0 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON, ENGLAND SW1Y 5DB SN 0308-0188 J9 INTERDISCIPL SCI REV JI Interdiscip. Sci. Rev. PD MAR PY 1992 VL 17 IS 1 BP 26 EP 31 PG 6 WC Multidisciplinary Sciences; Social Sciences, Interdisciplinary SC Science & Technology - Other Topics; Social Sciences - Other Topics GA HM066 UT WOS:A1992HM06600006 ER PT J AU BATUR, C SHARPLESS, RB DUVAL, WMB ROSENTHAL, BN AF BATUR, C SHARPLESS, RB DUVAL, WMB ROSENTHAL, BN TI SELF-TUNING MULTIVARIABLE POLE PLACEMENT CONTROL OF A MULTIZONE CRYSTAL-GROWTH FURNACE SO INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING LA English DT Note DE CRYSTAL GROWTH CONTROL; MULTIVARIABLE CONTROL SYSTEM ID BRIDGMAN AB This paper presents the design and implementation of a multivariable self-tuning temperature controller for the control of lead bromide crystal growth. The crystal grows inside a multizone transparent furnace. There are eight interacting heating zones shaping the axial temperature distribution inside the furnace. A multi-input, multi-output furnace model is identified on-line by a recursive least squares estimation algorithm. A multivariable pole placement controller based on this model is derived and implemented. Comparison between single-input, single-output and multi-input, multi-output self-tuning controllers demonstrates that the zone-to-zone interactions can be minimized better by a multi-input, multi-output controller design. This directly affects the quality of crystal grown. C1 UNIV AKRON,DEPT MECH ENGN,AKRON,OH 44325. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 6 TC 4 Z9 4 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0890-6327 J9 INT J ADAPT CONTROL JI Int. J. Adapt. Control Signal Process. PD MAR PY 1992 VL 6 IS 2 BP 127 EP 138 DI 10.1002/acs.4480060205 PG 12 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA JL784 UT WOS:A1992JL78400004 ER PT J AU DILL, LH BALASUBRAMANIAM, R AF DILL, LH BALASUBRAMANIAM, R TI UNSTEADY THERMOCAPILLARY MIGRATION OF ISOLATED DROPS IN CREEPING FLOW SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article DE DROPS; THERMOCAPILLARY FLOW; TRANSIENT FLOW; CREEPING FLOW; MICROGRAVITY; NEWTONIAN FLUIDS ID MARANGONI NUMBERS; BUBBLE MIGRATION; THERMAL-GRADIENT; GAS BUBBLE; MOTION; MICROGRAVITY; GRAVITY AB The problem of an isolated immiscible drop that slowly migrates due to unsteady thermocapillary stresses is considered. All physical properties except for interfacial tension are assumed constant for the two Newtonian fluids. Explicit expressions are found for the migration rate and stream functions in the Laplace domain. The resulting microgravity theory is useful, e.g., in predicting the distance a drop will migrate due to an impulsive interfacial temperature gradient as well as the time required to attain steady flow conditions from an initially resting state. C1 CASE WESTERN RESERVE UNIV,CLEVELAND,OH 44106. RP DILL, LH (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 22 TC 8 Z9 10 U1 1 U2 1 PU BUTTERWORTH-HEINEMANN PI WOBURN PA 225 WILDWOOD AVE #UNITB PO BOX 4500, WOBURN, MA 01801-2084 SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD MAR PY 1992 VL 13 IS 1 BP 78 EP 85 DI 10.1016/0142-727X(92)90062-E PG 8 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA HG905 UT WOS:A1992HG90500009 ER PT J AU PANCAKE, CM BAILEY, R BARKAI, D SMITH, B BRANDENBURG, J DONGARRA, J KALOS, M SNIR, M GELERNTER, D AF PANCAKE, CM BAILEY, R BARKAI, D SMITH, B BRANDENBURG, J DONGARRA, J KALOS, M SNIR, M GELERNTER, D TI WHAT SHOULD WE EXPECT FROM PARALLEL LANGUAGE STANDARDS SO INTERNATIONAL JOURNAL OF SUPERCOMPUTER APPLICATIONS AND HIGH PERFORMANCE COMPUTING LA English DT Discussion C1 CORNELL UNIV,CTR THEORY,ITHACA,NY 14853. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. INTEL CORP,SUPERCOMP SYST,SANTA CLARA,CA 95051. UNIV TENNESSEE,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN. YALE UNIV,DEPT COMP SCI,NEW HAVEN,CT 06520. CORNELL UNIV,CTR THEORY & SIMULAT SCI & ENGN,ITHACA,NY 14853. IBM CORP,THOMAS J WATSON RES CTR,PARALLEL SYST ORG,YORKTOWN HTS,NY 10598. RP PANCAKE, CM (reprint author), AUBURN UNIV,FAC COMP ENGN,DEPT COMP SCI & ENGN,AUBURN,AL 36849, USA. RI Snir, Marc/B-1050-2009 OI Snir, Marc/0000-0002-3504-2468 NR 10 TC 1 Z9 1 U1 0 U2 0 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 1078-3482 J9 INT J SUPERCOMPUT AP JI Int. J. Supercomput. Appl. High Perform. Comput. PD SPR PY 1992 VL 6 IS 1 BP 112 EP 117 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Computer Science GA HR667 UT WOS:A1992HR66700006 ER PT J AU KESSLER, DJ AF KESSLER, DJ TI CLEANING UP SPACE DEBRIS SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Letter RP KESSLER, DJ (reprint author), NASA,ORBITAL DEBRIS RES,HOUSTON,TX 77058, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD PRESS PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SPR PY 1992 VL 8 IS 3 BP 19 EP 20 PG 2 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA HN595 UT WOS:A1992HN59500021 ER PT J AU ROTH, KR FEARN, RL THAKUR, SS AF ROTH, KR FEARN, RL THAKUR, SS TI EVALUATION OF A NAVIER-STOKES PREDICTION OF A JET IN A CROSS-FLOW SO JOURNAL OF AIRCRAFT LA English DT Article AB The interaction between a subsonic jet exhausting perpendicularly through a flat plate into a crossflow is investigated numerically using an implicit, two-factor, partially flux split solver for the thin-layer Navier-Stokes equations. The numerical model is limited to steady and laminar flow for both the jet and crossflow. The accuracy of the method is assessed by comparing computed and experimental results for flows with jet-to-cross-flow velocity ratios of 4, 6, and 8. Qualitatively, it is found that all of the global flow physics, including the jet trajectory, the contrarotating vortex pair, entrainment, and the wake region near the flat plate, are captured numerically. The computed velocity field is analyzed to determine the properties of the contrarotating vortex pair. Reasonable quantitative agreement between the computation and the experiment is found for the vortex properties as well as for the jet centerline and the plate pressure distribution. Computational flow visualization techniques are used to provide insight into the physics of the three-dimensional flowfield. RP ROTH, KR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1992 VL 29 IS 2 BP 185 EP 193 DI 10.2514/3.46143 PG 9 WC Engineering, Aerospace SC Engineering GA HM898 UT WOS:A1992HM89800004 ER PT J AU MCMILLIN, SN PITTMAN, JL THOMAS, JL AF MCMILLIN, SN PITTMAN, JL THOMAS, JL TI COMPUTATIONAL STUDY OF INCIPIENT LEADING-EDGE SEPARATION ON A SUPERSONIC DELTA WING SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT 8TH CONF ON APPLIED AERODYNAMICS CY AUG 20-22, 1990 CL PORTLAND, OR SP AMER INST AERONAUT & ASTRONAUT AB A computational study on a 65 deg delta wing at a freestream Mach number of 1.60 has been conducted by obtaining conical Reynolds-averaged, Navier-Stokes solutions on a parametric series of geometries that varied in leading-edge radius and/or circular-arc camber. The computational results showed that increasing leading-edge radius or camber delay the onset of leading-edge separation on the leeside of a delta wing at a specific angle of attack. The Reynolds number was varied from 1 x 10(6)-5 x 10(6) for a turbulent boundary layer and was shown to have a minor effect on the effectiveness of leading-edge radius and/or camber in delaying the onset of leading-edge separation. Both laminar and turbulent boundary-layer models were investigated at a Reynolds number of 1 x 10(6), and the predicted flow pattern was found to change from attached flow for the turbulent boundary-layer model to separated flow for the laminar boundary-layer model. RP MCMILLIN, SN (reprint author), NASA,LANGLEY RES CTR,DIV APPL AERODYNAM,SUPERSON HYPERSON AERODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 0 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 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1992 VL 29 IS 2 BP 203 EP 209 DI 10.2514/3.46145 PG 7 WC Engineering, Aerospace SC Engineering GA HM898 UT WOS:A1992HM89800006 ER PT J AU DOGGETT, RV SOISTMANN, DL AF DOGGETT, RV SOISTMANN, DL TI LOW-SPEED FLUTTER CHARACTERISTICS OF SOME SIMPLE LOW-ASPECT-RATIO DELTA-WING MODELS SO JOURNAL OF AIRCRAFT LA English DT Article AB Some results from a combined experimental and analytical study of the low-speed flutter characteristics of low-aspect-ratio delta wings are presented. Data are presented showing the effects of sweep angle on the flutter characteristics of some simple plate models of constant planform area. The range of sweep angles studied was from 30 to 72 deg. In addition, flutter results are presented for two 30-deg-sweep clipped-delta-wing models. Also, results are presented that show the effects of root clamping (percentage length of the root chord that is cantilevered) for a 45-deg-sweep delta wing. The experimental data are compared with analytical results obtained by using kernel function and doublet-lattice subsonic unsteady lifting surface theories. RP DOGGETT, RV (reprint author), NASA,LANGLEY RES CTR,DIV STRUCT DYNAM,HAMPTON,VA 23665, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 1992 VL 29 IS 2 BP 273 EP 279 DI 10.2514/3.46155 PG 7 WC Engineering, Aerospace SC Engineering GA HM898 UT WOS:A1992HM89800016 ER PT J AU SMITH, SC AF SMITH, SC TI USE OF SHEAR-SENSITIVE LIQUID-CRYSTALS FOR SURFACE FLOW VISUALIZATION SO JOURNAL OF AIRCRAFT LA English DT Article AB The use of shear-sensitive liquid crystals has become an established technique for diagnostic flow visualization. This paper Presents an overview of the state of the art or the liquid-crystal technique, including the historical development and a discussion of how it is used. Sample results from several researchers demonstrate the range of flow features that can be illustrated, including laminar boundary-layer transition, laminar separation bubbles, shocks, and separation. The technique has been demonstrated in flight and wind-tunnel environments from subsonic to hypersonic speeds. RP SMITH, SC (reprint author), NASA,AMES RES CTR,ADV AERODYNAM CONCEPTS BRANCH,MOFFETT FIELD,CA 94035, USA. NR 0 TC 5 Z9 5 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 MAR-APR PY 1992 VL 29 IS 2 BP 289 EP 293 DI 10.2514/3.46157 PG 5 WC Engineering, Aerospace SC Engineering GA HM898 UT WOS:A1992HM89800018 ER PT J AU BAIK, JJ AF BAIK, JJ TI RESPONSE OF A STABLY STRATIFIED ATMOSPHERE TO LOW-LEVEL HEATING - AN APPLICATION TO THE HEAT-ISLAND PROBLEM SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID UPPER BOUNDARY-CONDITION; AIR-FLOW; MODELS; URBAN; RADIATION; DYNAMICS; WAVES AB Two-dimensional airflow characteristics past a heat island are investigated using both a linear analytic model and a nonlinear numerical model in the context of the response of a stably stratified atmosphere to specified low-level heating in a constant shear flow. Results from the steady-state, linear, analytic solutions exhibit typical flow response fields that gravity waves produce in response to the local heat source in the presence of environmental flow. The magnitude of the perturbation vertical velocity is shown to be much larger in the shear-flow case than in the uniform-flow case. This is because the basic-state wind shear is a source of the perturbation wave energy. Nonlinear numerical model experiments over a wide range of heating amplitudes are performed to examine nonlinear effects on the simulated flow field. For smaller heating amplitude (hence, smaller nonlinearity factor), the flow response field is similar to that produced by the linear gravity waves. On the other hand, two distinct flow features are observed for larger heating amplitude (hence, larger nonlinearity factor): the gravity-wave-type response field on the upstream side of the heat island and the strong updraft circulation cell located on the downstream side. As the heating amplitude increases, the updraft circulation cell strengthens and shifts farther downwind. The strong updraft cell is believed to be partly responsible for precipitation enhancement observed on the downstream side of the heat island. It is found that the continuing downwind propagation of the updraft circulation cell is related to basic-state wind speed. RP BAIK, JJ (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ATMOSPHERES LAB,HUNTSVILLE,AL 35812, USA. NR 26 TC 30 Z9 32 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 MAR PY 1992 VL 31 IS 3 BP 291 EP 303 DI 10.1175/1520-0450(1992)031<0291:ROASSA>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HJ008 UT WOS:A1992HJ00800006 ER PT J AU SCHWENKE, DW AF SCHWENKE, DW TI THE OPTIMIZATION OF SINGLE-MODE BASIS FUNCTIONS FOR POLYATOMIC VIBRATIONAL PROBLEMS WITH APPLICATION TO THE WATER MOLECULE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SELF-CONSISTENT FIELD; GROUND-STATE; ENERGIES AB We consider the optimization of the wave functions for coupled vibrations represented by linear combinations of products of functions depending only on a single vibrational coordinate. The functions themselves are optimized as well as the configuration list. For the H2O molecule, highly accurate results are obtained for the lowest 15 levels using significantly shorter expansions than would otherwise be possible. RP SCHWENKE, DW (reprint author), NASA, AMES RES CTR, MS 230-3, MOFFETT FIELD, CA 94035 USA. RI schwenke, david/I-3564-2013 NR 23 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1992 VL 96 IS 5 BP 3426 EP 3430 DI 10.1063/1.461945 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HG953 UT WOS:A1992HG95300009 ER PT J AU RIND, D BALACHANDRAN, NK SUOZZO, R AF RIND, D BALACHANDRAN, NK SUOZZO, R TI CLIMATE CHANGE AND THE MIDDLE ATMOSPHERE .2. THE IMPACT OF VOLCANIC AEROSOLS SO JOURNAL OF CLIMATE LA English DT Article ID EL-CHICHON; NORTHERN HEMISPHERE; LOWER STRATOSPHERE; SULFURIC-ACID; ERUPTION; MODEL; CIRCULATION; RADIATION; MEXICO; CLOUDS AB The effects of volcanic aerosols on the middle atmosphere are investigated with the Goddard Institute for Space Studies (GISS) Global Climate/Middle Atmosphere model. Volcanic aerosols with a visible optical depth of 0.15 are put into the lower stratosphere, and their influence is explored for different time scales: instantaneous effect (sea surface temperatures not allowed to adjust); influence for the first few years, with small tropospheric cooling; and long-term effect (50 years) with significant tropospheric cooling. The aerosols induce a direct stratospheric response, with warming in the tropical lower stratosphere, and cooling at higher latitudes. On the shorter time scales, this radiative effect increases tropospheric static stability at low- to midlatitudes, which reduces the intensity of the Hadley cell and Ferrel cell. There is an associated increase in tropospheric standing wave energy and a decrease in midlatitude west winds, which result in additional wave energy propagation into the stratosphere at lower midlatitudes in both hemispheres. Convergence of this flux in the middle atmosphere increases the residual circulation, producing low-latitude cooling and high-latitude warming near the stratopause. The dynamical changes are on the order of 10%, and are generally similar to occurrences following major volcanic eruptions in the last 30 years. On the longer time scale, a strong hemispheric asymmetry arises. In the Northern Hemisphere eddy energy decreases, as does the middle-atmosphere residual circulation, and widespread stratospheric cooling results. In the Southern Hemisphere, the large increase in sea ice increases the tropospheric latitudinal temperature gradient, leading to increased eddy energy, an increased middle-atmosphere residual circulation, and some high-latitude stratospheric warming. The different experiments emphasize that the middle-atmosphere response to climate change depends on both the direct and indirect (i.e., tropospheric) effects. Similarly, the tropospheric changes are not simply the products of the direct climate perturbation; they depend as well on what happens to the stratosphere. Such examples of the coupled systems underline the need to include both the troposphere and middle atmosphere in studying the effects of climate change. RP RIND, D (reprint author), GODDARD SPACE FLIGHT CTR,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 37 TC 62 Z9 63 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR PY 1992 VL 5 IS 3 BP 189 EP 208 DI 10.1175/1520-0442(1992)005<0189:CCATMA>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HP486 UT WOS:A1992HP48600001 ER PT J AU BUSHNELL, PG BRILL, RW AF BUSHNELL, PG BRILL, RW TI OXYGEN-TRANSPORT AND CARDIOVASCULAR-RESPONSES IN SKIPJACK TUNA (KATSUWONUS-PELAMIS) AND YELLOWFIN TUNA (THUNNUS-ALBACARES) EXPOSED TO ACUTE-HYPOXIA SO JOURNAL OF COMPARATIVE PHYSIOLOGY B-BIOCHEMICAL SYSTEMIC AND ENVIRONMENTAL PHYSIOLOGY LA English DT Article DE HYPOXIA; CARDIOVASCULAR; OXYGEN TRANSPORT; SKIPJACK TUNA KATSUWONUS-PELAMIS; YELLOWFIN TUNA, THUNNUS-ALBACARES ID TROUT SALMO-GAIRDNERI; DOGFISH SCYLIORHINUS-CANICULA; RAINBOW-TROUT; GAS-EXCHANGE; BLOOD-FLOW; FISH GILLS; HEART-RATE; CARDIAC-OUTPUT; GADUS-MORHUA; OPHIODON-ELONGATUS AB Responses to acute hypoxia were measured in skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacures) (almost-equal-to 1-3 kg body weight). Fish were prevented from making swimming movements by a spinal injection of lidocaine and were placed in front of a seawater delivery pipe to provide ram ventilation of the gills. Fish could set their own ventilation volumes by adjusting mouth gape. Heart rate, dorsal and ventral aortic blood pressures, and cardiac output were continuously monitored during normoxia (inhalant water (PO2 > 150 mmHg) and three levels of hypoxia (inhalant water PO2 almost-equal-to 130, 90, and 50 mmHg). Water and blood samples were taken for oxygen measurements in fluids afferent and efferent to the gills. From these data, various measures of the effectiveness of oxygen transfer, and branchial and systemic vascular resistance were calculated. Despite high ventilation volumes (4-71.min-1.kg-1), tunas extract approximately 50% of the oxygen from the inhalant water, in part because high cardiac outputs (115-132 ml.min-1.kg-1) result in ventilation/perfusion conductance ratios (0.75-1.1) close to the theoretically ideal value of 1.0. Therefore, tunas have oxygen transfer factors (ml O2.min-1.mmHg-1.kg-1) that are 10-50 times greater than those of other fishes. The efficiency of oxygen transfer from water in tunas (almost-equal-to 65%) matches that measured in teleosts with ventilation volumes an order of magnitude lower. The high oxygen transfer factors of tunas are made possible, in part, by a large gill surface area; however, this appears to carry a considerable osmoregulatory cost as the metabolic rate of gills may account for up 70% of the total metabolism in spinally blocked (i.e., non-swimming) fish. During hypoxia, skipjack and yellowfin tunas show a decrease in heart rate and increase in ventilation volume, as do other teleosts. However, in tunas hypoxic bradycardia is not accompanied by equivalent increases in stroke volume, and cardiac output falls as RR decreases. In both tuna species, oxygen consumption eventually must be maintained by drawing on substantial venous oxygen reserves. This occurs at a higher inhalant water PO2 (between 130 and 90 mmHg) in skipjack tuna than in yellowfin tuna (between 90 and 50 mmHg). The need to draw on venous oxygen reserves would make it difficult to meet the oxygen demand of increasing swimming speed, which is a common response to hypoxia in both species. Because yellowfin tuna can maintain oxygen consumption at a seawater oxygen tension of 90 mmHg without drawing on venous oxygen reserves, they could probably survive for extended periods at this level of hypoxia. C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822. UNIV HAWAII,JOHN A BURNS SCH MED,DEPT PHYSIOL,HONOLULU,HI 96822. NR 84 TC 74 Z9 74 U1 3 U2 15 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0174-1578 J9 J COMP PHYSIOL B JI J. Comp. Physiol. B-Biochem. Syst. Environ. Physiol. PD MAR PY 1992 VL 162 IS 2 BP 131 EP 143 DI 10.1007/BF00398338 PG 13 WC Physiology; Zoology SC Physiology; Zoology GA HJ081 UT WOS:A1992HJ08100005 PM 1592908 ER PT J AU REEDER, JR CREWS, JH AF REEDER, JR CREWS, JH TI REDESIGN OF THE MIXED-MODE BENDING DELAMINATION TEST TO REDUCE NONLINEAR EFFECTS SO JOURNAL OF COMPOSITES TECHNOLOGY & RESEARCH LA English DT Article DE COMPOSITES; DELAMINATION; MIXED-MODE; NONLINEAR ANALYSIS; TEST APPARATUS; TOUGHNESS, PEEK ID SPECIMEN AB The mixed-mode bending (MMB) test uses a lever to apply simultaneously Mode I and Mode II loading to a split-beam specimen. An iterative analysis that accounts for the geometric nonlinearity of the MMB test was developed. The analysis accurately predicted the measured load-displacement response and the strain energy release rate, G, of an MMB test specimen made of APC2(2) (AS4/PEEK). The errors in G when calculated using linear theory were found to be as large as 30% in some cases. Because it would be inconvenient to use a nonlinear analysis to analyze MMB data, the MMB apparatus was redesigned to minimize the nonlinearity. The nonlinear analysis was used as a guide in redesigning the MMB apparatus. With the improved apparatus, loads are applied just above the midplane of the test specimen through a roller attached to the lever. This apparatus was demonstrated by measuring the mixed-mode delamination fracture toughness of APC2. The nonlinearity errors associated with testing this tough composite material were less than +/- 3%. The data from the improved MMB apparatus analyzed with a linear analysis were similar to those found with the original apparatus and the nonlinear analysis. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 19 TC 75 Z9 76 U1 2 U2 10 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 SN 0884-6804 J9 J COMPOS TECH RES JI J. Compos. Technol. Res. PD SPR PY 1992 VL 14 IS 1 BP 12 EP 19 PG 8 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA JY515 UT WOS:A1992JY51500002 ER PT J AU BAZ, A POH, S FEDOR, J AF BAZ, A POH, S FEDOR, J TI INDEPENDENT MODAL SPACE CONTROL WITH POSITIVE POSITION FEEDBACK SO JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME LA English DT Article ID PIEZOELECTRIC ACTUATORS; FLEXIBLE SYSTEMS; ACTIVE CONTROL AB This study presents an Independent Modal Space Control (IMSC) algorithm whose modal control forces are generated based on a Positive Position Feedback (PPF) strategy. This is in contrast to conventional modal controllers that rely in their opeation on negative feedback of the modal position and velocity. The proposed algorithm combines the attractive attributes of both the IMSC and the PPF. It maintains the simplicity of the IMSC as it designs the controller of a complex structure at the uncoupled modal level. At the same time, it utilizes only the modal position signal to provide a damping action to undamped modes. The paper presents the theory behind this algorithm when using first order filters to achieve the PPF effect. The optimal time constants of the filters are determined. The performance of the algorithm is enhanced by augmenting it with a "time sharing" strategy to share a small number of actuators between larger number of modes. The effectiveness of the algorithm in damping out the vibration of flexible structures is validated experimentally. A simple cantilevered beam is used as an example of a flexible structure whose multi-modes of vibration are controlled by a single actuator. A piezo-electric actuator is utilized, in this regard, as a part of a computer-controlled active control system. The performance of the active control system is determined in the time and the frequency domains. The results are compared with those obtained when using the IMSC, PPF with second order filters, the Psuedo-Inverse (PI) and a Modified Independent Modal Space Control (MIMSC). The experimental results suggest the potential of the proposed method as a viable means for controlling the vibration of large flexible structures. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BAZ, A (reprint author), CATHOLIC UNIV AMER,DEPT MECH ENGN,WASHINGTON,DC 20064, USA. NR 23 TC 39 Z9 42 U1 1 U2 13 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-0434 J9 J DYN SYST-T ASME JI J. Dyn. Syst. Meas. Control-Trans. ASME PD MAR PY 1992 VL 114 IS 1 BP 96 EP 103 DI 10.1115/1.2896512 PG 8 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA HP704 UT WOS:A1992HP70400012 ER PT J AU ANTONIA, RA TEITEL, M KIM, J BROWNE, LWB AF ANTONIA, RA TEITEL, M KIM, J BROWNE, LWB TI LOW-REYNOLDS-NUMBER EFFECTS IN A FULLY-DEVELOPED TURBULENT CHANNEL FLOW SO JOURNAL OF FLUID MECHANICS LA English DT Article ID BOUNDARY-LAYER; WALL REGION; DUCT FLOW AB Low-Reynolds-number effects are observed in the inner region of a fully developed turbulent channel flow, using data obtained either from experiments or by direct numerical simulations. The Reynolds-number influence is observed on the turbulence intensities and to a lesser degree on the average production and dissipation of the turbulent energy. In the near-wall region, the data confirm Wei & Willmarth's (1989) conclusion that the Reynolds stresses do not scale on wall variables. One of the reasons proposed by these authors to account for this behaviour, namely the 'geometry' effect or direct interaction between inner regions on opposite walls, was investigated in some detail by introducing temperature at one of the walls, both in experiment and simulation. Although the extent of penetration of thermal excursions into the opposite side of the channel can be significant at low Reynolds numbers, the contribution these excursions make to the Reynolds shear stress and the spanwise vorticity in the opposite wall region is negligible. In the inner region, spectra and co-spectra of the velocity fluctuations u and v change rapidly with the Reynolds number, the variations being mainly confined to low wavenumbers in the u spectrum. These spectra, and the corresponding variances, are discussed in the context of the active/inactive motion concept and the possibility of increased vortex stretching at the wall. A comparison is made between the channel and the boundary layer at low Reynolds numbers. C1 NASA,AMES RES CTR,CTR TURBULENCE RES,MOFFETT FIELD,CA 94035. RP ANTONIA, RA (reprint author), UNIV NEWCASTLE,DEPT MECH ENGN,NEWCASTLE,NSW 2308,AUSTRALIA. OI Kim, John/0000-0002-6369-9264 NR 38 TC 153 Z9 154 U1 0 U2 15 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAR PY 1992 VL 236 BP 579 EP 605 DI 10.1017/S002211209200154X PG 27 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HK859 UT WOS:A1992HK85900024 ER PT J AU HULTGREN, LS AF HULTGREN, LS TI NONLINEAR SPATIAL EQUILIBRATION OF AN EXTERNALLY EXCITED INSTABILITY WAVE IN A FREE SHEAR-LAYER SO JOURNAL OF FLUID MECHANICS LA English DT Article ID TRANSITION AB A two-dimensional disturbance evolving from a strictly linear, finite-growth-rate instability wave with nonlinear effects first becoming important in the critical layer is considered. The analysis is carried out for a general weakly non-parallel mean flow using matched asymptotic expansions. The flow in the critical layer is governed by a nonlinear vorticity equation which includes a spatial-evolution term. As in Goldstein & Hultgren (1988), the critical layer ages into a quasi-equilibrium one and the initial exponential growth of the instability wave is converted into a weak algebraic growth during the roll-up process. This leads to a next stage of evolution where the instability-wave growth is simultaneously affected by mean-flow divergence and nonlinear critical-layer effects and is eventually converted to decay. Expansions for the various streamwise regions of the flow are combined into a single composite formula accounting for both shear-layer spreading and nonlinear critical-layer effects and good agreement with the experimental results of Thomas & Chu (1989), Freymuth (1966), and C.-M. Ho & Y. Zohar (1989, private communication) is demonstrated. RP HULTGREN, LS (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 16 TC 38 Z9 38 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAR PY 1992 VL 236 BP 635 EP 664 DI 10.1017/S0022112092001563 PG 30 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HK859 UT WOS:A1992HK85900026 ER PT J AU KANDIL, OA WONG, TC LIU, CH AF KANDIL, OA WONG, TC LIU, CH TI NUMERICAL-SIMULATION OF STEADY AND UNSTEADY ASYMMETRIC VORTICAL FLOW SO JOURNAL OF FLUIDS AND STRUCTURES LA English DT Article C1 NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. RP KANDIL, OA (reprint author), OLD DOMINION UNIV,DEPT MECH ENGN & MECH,NORFOLK,VA 23529, USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0889-9746 J9 J FLUID STRUCT JI J. Fluids Struct. PD MAR PY 1992 VL 6 IS 2 BP 249 EP 265 DI 10.1016/0889-9746(92)90047-7 PG 17 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA HK456 UT WOS:A1992HK45600006 ER PT J AU BERNARD, PS SPEZIALE, CG AF BERNARD, PS SPEZIALE, CG TI BOUNDED ENERGY-STATES IN HOMOGENEOUS TURBULENT SHEAR-FLOW - AN ALTERNATIVE VIEW SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID ISOTROPIC TURBULENCE AB The equilibrium structure of homogeneous turbulent shear flow is investigated from a theoretical standpoint. Existing turbulence models, in apparent agreement with physical and numerical experiments, predict an unbounded exponential time growth of the turbulent kinetic energy and dissipation rate; only the anisotropy tensor and turbulent time scale reach a structural equilibrium. It is shown that if a residual vortex stretching term is maintained in the dissipation rate transport equation, then there can exist equilibrium solutions, with bounded energy states, where the turbulence production is balanced by its dissipation. Illustrative calculations are presented for a k-epsilon model modified to account for net vortex stretching. The calculations indicate an initial exponential time growth of the turbulent kinetic energy and dissipation rate for elapsed times that are as large as those considered in any of the previously conducted physical or numerical experiments on homogeneous shear flow. However, vortex stretching eventually takes over and forces a production-equals-dissipation equilibrium with bounded energy states. The plausibility of this result is further supported by independent calculations of isotropic turbulence which show that when this vortex stretching effect is accounted for, a much more complete physical description of isotropic decay is obtained. It is thus argued that the inclusion of vortex stretching as an identifiable process may have greater significance in turbulence modeling than has previously been thought and that the generally accepted structural equilibrium for homogeneous shear flow, with unbounded energy growth, could be in need of re-examination. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. RP BERNARD, PS (reprint author), UNIV MARYLAND,DEPT MECH ENGN,COLLEGE PK,MD 20742, USA. NR 25 TC 15 Z9 15 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD MAR PY 1992 VL 114 IS 1 BP 29 EP 39 DI 10.1115/1.2909995 PG 11 WC Engineering, Mechanical SC Engineering GA HP713 UT WOS:A1992HP71300005 ER PT J AU SINGER, BA DINAVAHI, PG AF SINGER, BA DINAVAHI, PG TI TESTING OF TRANSITION-REGION MODELS SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB An approach for the comprehensive testing of transition-region models is described. This approach emphasizes the need to evaluate the models in all of the flow scenarios for which they are likely to be used. As an example of the procedure, seven different types of transitioning flows are described and experiments illustrating the different scenarios are discussed. Two transition-region models are used to predict mean-flow quantities for all of the cases and selected results are reported. RP SINGER, BA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 30 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 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD MAR PY 1992 VL 114 IS 1 BP 73 EP 79 DI 10.1115/1.2910003 PG 7 WC Engineering, Mechanical SC Engineering GA HP713 UT WOS:A1992HP71300012 ER PT J AU PARKS, GK FITZENREITER, R OGILVIE, KW HUANG, C ANDERSON, KA DANDOURAS, J FRANK, L LIN, RP MCCARTHY, M REME, H SAUVAUD, JA WERDEN, S AF PARKS, GK FITZENREITER, R OGILVIE, KW HUANG, C ANDERSON, KA DANDOURAS, J FRANK, L LIN, RP MCCARTHY, M REME, H SAUVAUD, JA WERDEN, S TI LOW-ENERGY PARTICLE LAYER OUTSIDE OF THE PLASMA SHEET BOUNDARY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-LATITUDE; ELECTRON-BEAMS; AURORAL-ZONE; ION-BEAMS; MAGNETOSPHERE; ALTITUDES; ISEE-1; FIELD AB The ISEE spacecraft in the geomagnetic tail frequently crossed the high-latitude boundary of the plasma sheet. On a number of these crossings on the morningside (between 15 R(E) and 22 R(E)) the ISEE instruments detected an enhanced population of low-energy electrons and ions immediately adjacent to the plasma sheet boundary layer (PSBL). The electrons in this low-energy layer (LEL) have energies less than a few hundred eV, and they are aligned along the magnetic field direction propagating in the tailward direction. The ions have energies less than 100 eV and are also streaming along the magnetic field direction but in the earthward direction. These particles are clearly distinguished from the bulk of the particles in the plasma sheet and the PSBL. These observations may help clarify where the various particle features in the geomagnetic tail map to in the ionosphere. It is suggested that the LEL maps to the soft (< 1 keV) electron precipitation region poleward of the plasma sheet boundary. C1 UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. CTR ETUDE SPATIALE RAYONNEMENT,F-31029 TOULOUSE,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV IOWA,DEPT PHYS,IOWA CITY,IA 52242. RP PARKS, GK (reprint author), UNIV WASHINGTON,GEOPHYS PROGRAM,AK 50,SEATTLE,WA 98195, USA. NR 26 TC 36 Z9 36 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 MAR 1 PY 1992 VL 97 IS A3 BP 2943 EP 2954 DI 10.1029/91JA02391 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HG749 UT WOS:A1992HG74900011 ER PT J AU AGGSON, TL MAYNARD, NC HANSON, WB SABA, JL AF AGGSON, TL MAYNARD, NC HANSON, WB SABA, JL TI ELECTRIC-FIELD OBSERVATIONS OF EQUATORIAL BUBBLES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID DEPLETED PLASMA REGIONS; SPREAD-F; IONOSPHERE; IRREGULARITIES; WINDS; STRIATION; CLOUDS AB We present here results from the double floating probe experiment carried on the San Marco D satellite, with emphasis on the observation of large incremental changes in the convective electric field vector at the boundary of equatorial plasma bubbles. This study concentrates on isolated bubble structures in the upper ionospheric F region and divides these observed bubble encounters into two types, type I (live bubbles) and type II (dead bubbles). Type I bubbles show varying degrees of plasma density depletion and upward velocities ranging from 100 to 1000 m/s. Type II bubbles show plasma density depletion but no appreciable upward convection. Both types of events are often surrounded by a halo of plasma turbulence extending considerably outside the region's plasma depletion. Most type I events show some evidence for local continuity in the eastward (y) electric current, where the y component of the observed electric field (E(y)) shows hyperbolic correlation with the plasma density (n), as dictated by horizontal current continuity. This model stresses the importance of including magnetic field aligned currents in deriving the electric potential equation from the divergence equation del . j = 0. All of the type I (live) events examined exhibit a striking and systematic lack of conservation of the vertical component (x) of the electric field vector (E(x)) on crossing these structures. This lack of conservation of E(x) is of the order of 1.5 mV/m from west to east, directly implying that type I bubbles are not steady state plasma structures. A straightforward interpretation of this jump phenomenon in E(x) leads to the conclusion that the walls of most of the type I bubbles are collapsing inward at the rate of some 50 m/s. Since the average east-west dimension of the bubble structures we have examined here is of the order of 40 km, we conclude that the average lifetime of the strong upward convection phase is about 15 min. This suggests that after 15 min or so these type I events may be pinched off from the low densities of the bottomside F region and the bubbles perhaps become type II events which continue to drift eastward with the general background zonal plasma flow during the equatorial night. It is argued that the collapse motions may be driven by an asymmetry between the upwind (west) and downwind (east) E region drag on the F region eastward dynamo motions. Such an asymmetry appears to be of the proper magnitude and direction to produce the observed (approximately 1.5 mV/m) jump in the tangential (vertical) component of E on crossing these events. C1 UNIV TEXAS,CTR SPACE SCI,RICHARDSON,TX 75083. AIR FORCE GEOPHYS LAB,BEDFORD,MA 01731. ST SYST CORP,LANHAM,MD 20706. RP AGGSON, TL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 696,GREENBELT,MD 20771, USA. NR 22 TC 54 Z9 54 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1992 VL 97 IS A3 BP 2997 EP 3009 DI 10.1029/90JA02356 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HG749 UT WOS:A1992HG74900016 ER PT J AU SISKIND, DE RUSCH, DW AF SISKIND, DE RUSCH, DW TI NITRIC-OXIDE IN THE MIDDLE TO UPPER THERMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-CYCLE VARIATION; ODD NITROGEN; IONIZATION FREQUENCIES; GLOBAL DISTRIBUTION; MEAN STRUCTURE; E REGION; NO; MODEL; ATMOSPHERE; SATELLITE AB We review the results of six rocket observations of thermospheric nitric oxide and attempt to reconcile them with the available laboratory photochemical data. Specifically, we assess the impact of the recently revised recommendation for the N(4S) + O2 rate coefficient on photochemical models. Use of the new rate coefficient leads to a significantly enhanced production of NO, particularly at F region altitudes during solar maximum conditions. A comparison of photochemical calculations with the rocket profiles indicates that the new rate coefficient introduces a significant discrepancy which can be resolved if the recombination reaction of N + NO is temperature dependent. Our best fit value for the N + NO rate coefficient at thermospheric temperatures is 1.6 x 10(-10) exp (-(460 +/- 60)/T). The temperature dependence of this rate coefficient disagrees with the current recommendation from the Jet Propulsion Laboratory, but it is in better agreement with another, earlier laboratory measurement. Calculations using our proposed rate coefficient predict the NO solar cycle variation at 180 km to be less than at 140 km which is also in agreement with the observations. It is likely that the use of these new rate coefficients will affect calculations of the thermal budget of the upper atmosphere as well as the downward transport of NO into the middle atmosphere. C1 UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,BOULDER,CO 80309. RP SISKIND, DE (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401B,HAMPTON,VA 23665, USA. NR 53 TC 33 Z9 33 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAR 1 PY 1992 VL 97 IS A3 BP 3209 EP 3217 DI 10.1029/91JA02657 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HG749 UT WOS:A1992HG74900033 ER PT J AU WU, JT AF WU, JT TI ORBIT DETERMINATION BY SOLVING FOR GRAVITY PARAMETERS WITH MULTIPLE ARC DATA SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SATELLITE AB The orbit of a satellite that repeats in the Earth fixed coordinates is determined by combining GPS tracking data from multiple arcs. The satellite dynamics are modeled with the epoch state and a set of parameters, called the bin parameters, that account for the effect of the local gravitational field on the satellite current state. The epoch state is specific to each arc, and the bin parameters are common to all repeat arcs. The estimation algorithm is based on the Square Root Information Filter. It involves partitioning of the measurement matrix and use of the Householder transformation to combine multiple arc data and solve for the epoch states and the bin parameters. The bin parameters can then be converted into the Earth's gravitational field with a modest amount of computation. RP WU, JT (reprint author), CALTECH,JET PROP LAB,TRACKING SYST & APPLICAT SECT,PASADENA,CA 91109, USA. NR 35 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1992 VL 15 IS 2 BP 304 EP 313 DI 10.2514/3.20838 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100003 ER PT J AU WILLIAMS, T JUANG, JN AF WILLIAMS, T JUANG, JN TI SENSITIVITY OF THE TRANSMISSION ZEROS OF FLEXIBLE SPACE STRUCTURES SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID LINEAR-MULTIVARIABLE SYSTEMS; EIGENVALUE AB The uncertainties inherent in the dynamics of flexible spacecraft make sensitivity and robustness questions very important when designing vibration isolation systems for these vehicles. One technique recently proposed for this problem is pole/zero cancellation, in which the feedback is used to make as many closed-loop modes as possible unobservable at the points on the structure where vibrations are to be minimized. Study of the robustness properties of this approach first requires an analysis of the sensitivity of the transmission zeros of second-order structural models. These questions are addressed in this paper, where it is proved (first in terms of partial derivatives and then condition numbers) that the sensitivities of the transmission zeros of any structure with collocated sensors and actuators are closely related to those of the poles of the system. Furthermore, the closed-loop poles produced by applying pole/zero cancellation to such a structure are shown to have sensitivities approaching those of the zeros, so these too are approximately given from the sensitivities of the open-loop poles. Finally, these points are illustrated by simple examples. C1 NASA,LANGLEY RES CTR,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23665. RP WILLIAMS, T (reprint author), UNIV CINCINNATI,DEPT AEROSP ENGN,CINCINNATI,OH 45221, USA. NR 21 TC 3 Z9 3 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 MAR-APR PY 1992 VL 15 IS 2 BP 368 EP 375 DI 10.2514/3.20845 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100010 ER PT J AU DUYAR, A MERRILL, W AF DUYAR, A MERRILL, W TI FAULT-DIAGNOSIS FOR THE SPACE-SHUTTLE MAIN ENGINE SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID DYNAMIC-SYSTEMS AB A conceptual design of a model-based fault detection and diagnosis system is developed for the Space Shuttle main engine. The design approach consists of process modeling, residual generation, and fault detection and diagnosis. The engine is modeled using a discrete time, quasilinear state-space representation. Model parameters are determined by identification. Residuals generated from the model are used by a neural network to detect and diagnose engine component faults. Fault diagnosis is accomplished by training the neural network to recognize the pattern of the respective fault signatures. Preliminary results for a failed valve, generated using a full, nonlinear simulation of the engine, are presented. These results indicate that the developed approach can be used for fault detection and diagnosis. The results also show that the developed model is an accurate and reliable predictor of the highly nonlinear and very complex engine. C1 NASA,LEWIS RES CTR,ADV CONTROLS TECHNOL BRANCH,CLEVELAND,OH 44135. RP DUYAR, A (reprint author), FLORIDA ATLANTIC UNIV,DEPT MECH ENGN,BOCA RATON,FL 33431, USA. NR 15 TC 13 Z9 13 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 MAR-APR PY 1992 VL 15 IS 2 BP 384 EP 389 DI 10.2514/3.20847 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100012 ER PT J AU MENON, PKA DUKE, EL AF MENON, PKA DUKE, EL TI TIME-OPTIMAL AIRCRAFT PURSUIT EVASION WITH A WEAPON ENVELOPE CONSTRAINT SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID SYSTEMS; GAME AB An optimal pursuit-evasion problem between two aircraft including a realistic weapon envelope is analyzed using differential game theory. This study employs sixth-order nonlinear point mass vehicle models and allows the inclusion of an arbitrary weapon envelope geometry. The performance index is a linear combination of flight time and the square of the vehicle acceleration. Closed-form solution to this high-order differential game is then obtained using feedback linearization. The solution is in the form of a feedback guidance law together with a quartic polynomial for time to go. Because of its modest computational requirements, this nonlinear guidance law is useful for onboard real-time implementations. C1 NASA,AMES DRYDEN FLIGHT RES FACIL,DRYDEN RES ENGN DIV,MS OFDC,EDWARDS,CA 93523. GEORGIA INST TECHNOL,SCH AEROSP ENGN,ATLANTA,GA 30332. NR 19 TC 8 Z9 10 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1992 VL 15 IS 2 BP 448 EP 456 DI 10.2514/3.20856 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100021 ER PT J AU ESHOW, MM AF ESHOW, MM TI FLIGHT INVESTIGATION OF VARIATIONS IN ROTORCRAFT CONTROL AND DISPLAY DYNAMICS FOR HOVER SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB This paper describes a flight investigation of the handling qualities issues associated with variations in display dynamics for varying levels of vehicle augmentation. The experiment was conducted on the NASA/Army CH-47B Variable-Stability Research Helicopter using its model-following control system and a color, panel-mounted display. A display law design method developed and flight tested previously was refined and expanded to account for guidance effects. Specifically, for rate, attitude, and velocity command vehicle response types, both integrator-like and gain-like display controlled element dynamics were evaluated in two hovering tasks conducted in simulated zero-visibility conditions. The tasks were performed both with and without automation of the vertical and directional axes to assess the impact of divided attention on performance and work load. Quantitative and subjective data describing the pilots' ability to perform the tasks were collected and analyzed, and pilot-vehicle-display dynamics were identified. Results indicated that gain-like display dynamics were generally preferred and resulted in better inner-loop tracking and higher inner-loop crossover frequencies, while not degrading outer-loop position performance. RP ESHOW, MM (reprint author), USA,NASA,AMES RES CTR,ARMY AEROFLIGHT DYNAM DIRECTORATE,FLIGHT CONTROL BRANCH,AVIAT SYST COMMAND,MOFFETT FIELD,CA 94035, USA. NR 19 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 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 1992 VL 15 IS 2 BP 482 EP 490 DI 10.2514/3.20861 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100026 ER PT J AU OSTROFF, AJ AF OSTROFF, AJ TI HIGH-ALPHA APPLICATION OF VARIABLE-GAIN OUTPUT-FEEDBACK CONTROL SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB This paper describes a recently developed variable-gain, optimal, discrete, output feedback design approach that is applied in a nonlinear flight regime. The flight regime covers a wide angle-of-attack alpha-range that includes the stall region. The paper contains brief descriptions of the variable-gain formulation, the discrete-control structure and flight equations used to apply the design approach, and the high-performance airplane model used in the application. Both linear and nonlinear analyses are shown for a longitudinal four-model integrated design case with alpha = 5, 15, 35, and 60 deg and two flight control modes. Nonlinear simulations show good time response for both a longitudinal pitch-up and pitch-down maneuver and a regulation within 5 deg from the nominal angle during a high-alpha lateral maneuver. RP OSTROFF, AJ (reprint author), NASA,LANGLEY RES CTR,DIV GUIDANCE & CONTROL,AIRCRAFT GUIDANCE & CONTROL BRANCH,HAMPTON,VA 23665, USA. NR 15 TC 9 Z9 9 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 MAR-APR PY 1992 VL 15 IS 2 BP 491 EP 497 DI 10.2514/3.20862 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100027 ER PT J AU MAGHAMI, PG JUANG, JN LIM, KB AF MAGHAMI, PG JUANG, JN LIM, KB TI EIGENSYSTEM ASSIGNMENT WITH OUTPUT-FEEDBACK SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note ID POLE ASSIGNMENT; MULTIVARIABLE SYSTEMS; SYLVESTER EQUATION RP MAGHAMI, PG (reprint author), NASA,LANGLEY RES CTR,SPACECRAFT CONTROLS BRANCH,MAIL STOP 230,HAMPTON,VA 23665, USA. NR 15 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 MAR-APR PY 1992 VL 15 IS 2 BP 531 EP 536 DI 10.2514/3.20870 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA HK051 UT WOS:A1992HK05100035 ER PT J AU NOEBE, RD CULLERS, CL BOWMAN, RR AF NOEBE, RD CULLERS, CL BOWMAN, RR TI THE EFFECT OF STRAIN RATE AND TEMPERATURE ON THE TENSILE PROPERTIES OF NIAL SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID DUCTILE TRANSITION; GRAIN-SIZE; BRITTLE; FRACTURE AB Tensile testing of cast and extruded binary NiAl was performed from 300 to 900 K at strain rates of 1.4 x 10(-4) to 1.4 x 10(-1) s-1. The brittle-to-ductile transition temperature (BDTT) was dependent on strain rate, with a three order of magnitude increase in strain rate resulting in approximately a 200 K increase in transition temperature. Regardless of strain rate, at temperatures just above the BDTT the fracture strength increased significantly and the fracture morphology changed from mostly intergranular to predominantly transgranular. It was also determined that the mechanism responsible for the brittle-to-ductile transition in NiAl had an apparent activation energy of approximately 118 kJ/mol. These results support the argument that the mechanism for the brittle-to-ductile transition in NiAl is associated with the onset of a thermally activated deformation process. This process is probably dislocation climb controlled by short circuit diffusion. RP NOEBE, RD (reprint author), NASA,LEWIS RES CTR,MS 49-3,CLEVELAND,OH 44135, USA. NR 39 TC 63 Z9 65 U1 0 U2 5 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAR PY 1992 VL 7 IS 3 BP 605 EP 612 DI 10.1557/JMR.1992.0605 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA HH520 UT WOS:A1992HH52000013 ER PT J AU HILICO, JC LOETE, M BROWN, LR AF HILICO, JC LOETE, M BROWN, LR TI LINE STRENGTHS OF THE NU-2 + NU-3 AND NU-3-NU-2 BANDS OF METHANE ((CH4)-C-12)1 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ABSOLUTE FREQUENCY MEASUREMENTS; 6-10 MU-M; TETRAHEDRAL MOLECULES; DIPOLE-MOMENT; METHANE; PARAMETERS; (CH4)-C-12; BANDS; SPECTROSCOPY; INTENSITIES C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP HILICO, JC (reprint author), UNIV BOURGOGNE,SPECTRON MOLEC & INSTRUMENTAT LASER LAB,CNRS,UA 777,6 BD GABRIEL,F-21000 DIJON,FRANCE. NR 40 TC 17 Z9 17 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAR PY 1992 VL 152 IS 1 BP 229 EP 251 DI 10.1016/0022-2852(92)90134-A PG 23 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA HE082 UT WOS:A1992HE08200024 ER PT J AU ARIF, H AYDELOTT, JC CHATO, DJ AF ARIF, H AYDELOTT, JC CHATO, DJ TI EVALUATION OF SUPERCRITICAL CRYOGEN STORAGE AND TRANSFER SYSTEMS FOR FUTURE NASA MISSIONS SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Conceptual designs of space transportation vehicles (STV) and their orbital servicing facilities, which utilize supercritical, single-phase, cryogenic propellants, have been established and compared with conventional subcritical, two-phase, STV concepts. The analytical study was motivated by the desire to avoid fluid-management problems associated with the storage, acquisition, and transfer of subcritical liquid oxygen and hydrogen propellants in the low-gravity environment of space. Although feasible, the supercritical concepts suffer from STV weight penalties and propellant resupply system power requirements that make the concepts impractical. C1 NASA,LEWIS RES CTR,CRYOGEN FLUIDS TECHNOL OFF,CLEVELAND,OH 44135. RP ARIF, H (reprint author), NASA,LEWIS RES CTR,STRUCT ANAL BRANCH,ENGN DIRECTORATE,CLEVELAND,OH 44135, USA. RI Chato, David/B-2698-2013 OI Chato, David/0000-0003-2990-0646 NR 6 TC 0 Z9 0 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1992 VL 8 IS 2 BP 332 EP 338 DI 10.2514/3.23482 PG 7 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400012 ER PT J AU AMERI, AA SOCKOL, PM GORLA, RSR AF AMERI, AA SOCKOL, PM GORLA, RSR TI NAVIER-STOKES ANALYSIS OF TURBOMACHINERY BLADE EXTERNAL HEAT-TRANSFER SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The two-dimensional, compressible, thin-layer Navier-Stokes and energy equations were solved numerically to obtain heat transfer rates on turbomachinary blades. The Baldwin-Lomax algebraic model and the q - omega low Reynolds number, two-equation model were used for modeling of turbulence. For the numerical solution of the governing equations a four-stage Runge-Kutta solver was employed. The turbulence model equations were solved using an implicit scheme. Numerical solutions are presented for two-dimensional flow within two vane cascades. The heat transfer results and the pressure distributions were compared with published experimental data. The agreement between the numerical calculations and the experimental values were found to be generally favorable. The position of transition from laminar to turbulent flow was also predicted accurately. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP AMERI, AA (reprint author), CLEVELAND MUSEUM ART,DEPT MECH ENGN,CLEVELAND,OH 44106, USA. NR 20 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1992 VL 8 IS 2 BP 374 EP 381 DI 10.2514/3.23488 PG 8 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400018 ER PT J AU ARNONE, A LIOU, MS POVINELLI, LA AF ARNONE, A LIOU, MS POVINELLI, LA TI NAVIER-STOKES SOLUTION OF TRANSONIC CASCADE FLOWS USING NONPERIODIC C-TYPE GRIDS SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID EQUATIONS AB A new kind of C-type grid is proposed for turbomachinery flow calculations. This grid is nonperiodic on the wake and results in minimum skewness for cascades with high turning and large camber. The Reynolds-averaged Navier-Stokes equations are discretized on this type of grid using a finite volume approach. The Baldwin-Lomax eddy-viscosity model is used for turbulence closure. Jameson's explicit Runge-Kutta scheme is adopted for the integration in time, and computational efficiency is achieved through accelerating strategies such as multigriding and residual smoothing. A detailed numerical study has been carried out for a turbine rotor and for a vane. A grid dependence analysis is presented and the effect of the artificial dissipation is also investigated. Comparison of calculations with experiments clearly demonstrate the advantage of the proposed grid. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP ARNONE, A (reprint author), UNIV FLORENCE,FAC RES,DEPT ENERGY ENGN,I-50121 FLORENCE,ITALY. OI Arnone, Andrea/0000-0001-7471-4442 NR 20 TC 49 Z9 50 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 MAR-APR PY 1992 VL 8 IS 2 BP 410 EP 417 DI 10.2514/3.23493 PG 8 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400023 ER PT J AU CLAUS, RW VANKA, SP AF CLAUS, RW VANKA, SP TI MULTIGRID CALCULATIONS OF A JET IN CROSS-FLOW SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID ROUND JET; FLOW; FIELD AB In order to assess accurately the standard k-epsilon model in a three-dimensional recirculating flow, a series of numerical calculations of a jet in a crossflow have been made employing progressively fine finite-difference meshes consisting of up to 2.4 million grid nodes. The discretized equations have been solved with a block-implicit multigrid algorithm that is observed to converge efficiently. The calculated velocity and turbulence fields are compared with experimental data. It is observed that the general features of the flow are well predicted, but there are appreciable discrepancies between measured and calculated values. Even with current fine resolution, the calculation cannot be said to be completely grid independent; however, the major disagreements are believed to result from the turbulence model. C1 UNIV ILLINOIS,DEPT MECH & IND ENGN,URBANA,IL 61801. RP CLAUS, RW (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135, USA. NR 23 TC 17 Z9 17 U1 0 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 MAR-APR PY 1992 VL 8 IS 2 BP 425 EP 431 DI 10.2514/3.23495 PG 7 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400025 ER PT J AU REDDY, DR WEIR, LJ AF REDDY, DR WEIR, LJ TI 3-DIMENSIONAL VISCOUS ANALYSIS OF A MACH-5 INLET AND COMPARISON WITH EXPERIMENTAL-DATA SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A time-marching three-dimensional full Navier-Stokes code is applied to simulate the flow for a Mach 5 inlet experimental configuration using the data obtained in the 10- x 10-ft supersonic wind tunnel at the NASA Lewis Research Center. For the first time, a solution is obtained for this configuration with the actual geometry, the tunnel conditions, and all the bleed zones modeled in the computation. Computed pitot pressure profiles and static pressures at various locations in the inlet are compared with the corresponding experimental data. The effect of bleed zones is simulated reasonably well using approximations for the bleed boundary conditions and the turbulence model. C1 SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,BROOK PK,OH 44142. RP REDDY, DR (reprint author), NASA,LEWIS RES CTR,COMPUTAT FLUID DYNAM BRANCH,21000 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 12 TC 7 Z9 8 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 MAR-APR PY 1992 VL 8 IS 2 BP 432 EP 440 DI 10.2514/3.23496 PG 9 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400026 ER PT J AU NORTHAM, GB GREENBERG, I BYINGTON, CS CAPRIOTTI, DP AF NORTHAM, GB GREENBERG, I BYINGTON, CS CAPRIOTTI, DP TI EVALUATION OF PARALLEL INJECTOR CONFIGURATIONS FOR MACH-2 COMBUSTION SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB An experimental study of wall-mounted parallel injector ramps has been conducted to explore techniques to enhance mixing in a scramjet combustor. Downstream parallel injection may be useful at high speeds to extract thrust from hydrogen that has been used to cool the engine and the airframe. The swept ramp fuel injector employed here should produce vortex shedding and local separation (like a rearward-facing step), which should enhance mixing. Perpendicular fuel injectors were added downstream of the swept ramps to determine if the vortical wake flow generated by the parallel injectors-with no fuel injection-is effective in enhancing the mixing of the transverse fuel jet. For performance comparisons, an unswept, but otherwise identical, parallel injector was also tested. The injector ramps were designed to yield a reflected shock wave from the duct top wall such that it passed just downstream of the barrel shock of the fuel injectors. The Mach number at the exit of the fuel injector was designed to be 1.7 to produce an underexpanded fuel flow under almost all operating conditions. Direct-connect tests were conducted with a vitiated heater over a total temperature range. Flow visualization tests with an unducted freejet configuration were conducted using shadowgraph and ultraviolet television camera systems for OH radical visualization. Three duct configurations were tested. Tests of the swept ramp with a 100-mm constant-area duct downstream of the injector block resulted in upstream interaction at almost any equivalence ratio. Increasing the duct expansion rate allowed the equivalence ratio to be increased beyond 1.5 with rapid mixing and combustion over a wide total temperature range. The unswept ramp design resulted in lower combustion efficiency and a sensitivity of efficiency to heater total temperature, or duct velocity. C1 GEORGE WASHINGTON UNIV,JOINT INST ADV FLIGHT SCI,EXPTL METHODS BRANCH,HAMPTON,VA 23665. ANALYT SERV & MAT,HAMPTON,VA 23665. RP NORTHAM, GB (reprint author), NASA,LANGLEY RES CTR,EXPTL METHODS BRANCH,HAMPTON,VA 23665, USA. NR 13 TC 31 Z9 34 U1 2 U2 8 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 MAR-APR PY 1992 VL 8 IS 2 BP 491 EP 499 DI 10.2514/3.23503 PG 9 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400033 ER PT J AU DORNEY, DJ DAVIS, RL EDWARDS, DE MADAVAN, NK AF DORNEY, DJ DAVIS, RL EDWARDS, DE MADAVAN, NK TI UNSTEADY ANALYSIS OF HOT STREAK MIGRATION IN A TURBINE STAGE SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID REDISTRIBUTION AB Experimental data taken from gas turbine engines have shown that hot streaks existing combustors can have a significant impact upon the secondary flow and wall temperature of the first-stage turbine rotor. Understanding the secondary flow and heat transfer effects due to combustor hot streaks is essential to turbine designers attempting to optimize turbine cooling systems. A numerical investigation is presented that addresses the issues of multiblade count ratio and three-dimensionality effects on the prediction of combustor hot-streak migration in a turbine stage. The two- and three-dimensional Navier-Stokes analyses developed by Rai et al. are used to predict unsteady viscous rotor-stator interacting flow in the presence of a combustor hot streak. Predicted results are presented for a two-dimensional three-stator/four-rotor, a two-dimensional one-stator/one-rotor, and a three-dimensional one-stator/one-rotor simulation of hot-streak migration through a turbine stage. Comparison of these results with experimental data demonstrates the capability of the three-dimensional procedure to capture flow features associated with hot-streak migration including the effects of combustor hot streaks on turbine rotor surface temperatures. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNITED TECHNOL RES CTR,PHYS & MATH MODELING GRP,E HARTFORD,CT 06108. RP DORNEY, DJ (reprint author), UNITED TECHNOL RES CTR,THEORET & COMPUTAT FLUID DYNAM GRP,E HARTFORD,CT 06108, USA. NR 15 TC 68 Z9 69 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1992 VL 8 IS 2 BP 520 EP 529 DI 10.2514/3.23507 PG 10 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400037 ER PT J AU SMITH, CF MCARDLE, JG AF SMITH, CF MCARDLE, JG TI FLOW IN A VENTRAL NOZZLE FOR SHORT TAKEOFF AND VERTICAL LANDING AIRCRAFT SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB Short takeoff and vertical landing (STOVL) aircraft are planned for possible future development. For these aircraft, the same propulsion system will provide power for lift, hover, and horizontal flight. To accomplish this, many designs include a ventral nozzle to provide part of the vertical thrust required. Understanding and predicting the internal aerodynamic flow caused by a single exhaust duct opening are highly desirable in assessing this concept. This paper presents a numerical simulation of a ventral nozzle and compares the results with experimental data. Comparisons include visualizations of the flow along the ventral duct walls and in the tailpipe plane of symmetry. Performance calculations are also compared with measured values. C1 NASA,LEWIS RES CTR,DIV PROP SYST,SUPERSON & POWERED LIFT BRANCH,CLEVELAND,OH 44135. RP SMITH, CF (reprint author), SVERDRUP TECHNOL INC,LEWIS RES CTR GRP,PROP AERODYNAM SECT,BROOK PK,OH 44142, USA. NR 12 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 1992 VL 8 IS 2 BP 530 EP 536 DI 10.2514/3.23508 PG 7 WC Engineering, Aerospace SC Engineering GA HK434 UT WOS:A1992HK43400038 ER PT J AU BINIENDA, WK REDDY, ES AF BINIENDA, WK REDDY, ES TI MIXED-MODE FRACTURE IN UNIDIRECTIONAL GRAPHITE EPOXY COMPOSITE LAMINATES WITH CENTRAL NOTCH SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article ID SIMULATION AB Mixed-mode matrix fracture in central notched off-axis unidirectional composite laminates was investigated. A limited number of unidirectional tensile type specimens with a central, horizontal, notch were tested. Crack initiation and propagation were examined under various local stress fields that were controlled by fiber orientations. The tested specimens were simulated using a two dimensional finite element method with constant strain loading. The strain energy release rates along the crack were evaluated via crack closure technique. The variation of critical strain energy rates with off-axis angle was studied. The results from single (one-sided) and double (two-sided) crack simulations were presented and compared. C1 SVERDRUP TECHNOL INC,NASA,LEWIS RES CTR GRP,BROOK PK,OH 44142. RP BINIENDA, WK (reprint author), UNIV AKRON,DEPT CIVIL ENGN,AKRON,OH 44325, USA. NR 15 TC 2 Z9 2 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 MAR PY 1992 VL 11 IS 3 BP 324 EP 338 DI 10.1177/073168449201100306 PG 15 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA HJ054 UT WOS:A1992HJ05400006 ER PT J AU JAMSHIDI, M HAYATI, S AF JAMSHIDI, M HAYATI, S TI ROBOTS IN UNSTRUCTURED AND RADIOACTIVE ENVIRONMENTS SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Editorial Material C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP JAMSHIDI, M (reprint author), UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,CAD LAB INTELLIGENT & ROBOT SYST,ALBUQUERQUE,NM 87131, 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 0741-2223 J9 J ROBOTIC SYST JI J. Robot. Syst. PD MAR PY 1992 VL 9 IS 2 BP 141 EP 143 DI 10.1002/rob.4620090202 PG 3 WC Robotics SC Robotics GA HG030 UT WOS:A1992HG03000001 ER PT J AU HAYATI, S BALARAM, J AF HAYATI, S BALARAM, J TI SUPERVISORY TELEROBOTICS TESTBED FOR UNSTRUCTURED ENVIRONMENTS SO JOURNAL OF ROBOTIC SYSTEMS LA English DT Article AB This article describes a telerobotics testbed for performing tasks such as assembly and repair of spacecraft in unstructured environments. This fully operational multiarm system can operate in teleoperated or supervisory control modes, as well as mixed shared-control modes, thus enabling operations in totally to partially unstructured environments. Various sources of uncertainty are identified and approaches to minimize their effects are presented. In the teleoperated mode, the system uses two force-reflecting hand controllers to operate two manipulator arms. A third arm is utilized to Position four cameras to view the scene. In the supervisory mode, the system can be operated from three different levels: task, process, and servo levels, providing different levels of autonomy and performance. Various tools are provided so that an operator can perform tasks even when objects are partially occluded or their positions are not known a priori. Facilities are available for building models of previously unknown objects on-line, as well as generating collision-free motions. Architecturally, the system is designed so that an operator and much of the associated computing environment can be located remotely relative to the robots. As such, ground-controlled remote manipulation is possible. RP HAYATI, S (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 24 TC 5 Z9 5 U1 1 U2 1 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 MAR PY 1992 VL 9 IS 2 BP 261 EP 280 DI 10.1002/rob.4620090210 PG 20 WC Robotics SC Robotics GA HG030 UT WOS:A1992HG03000009 ER PT J AU GUPTA, RN LEE, KP MOSS, JN SUTTON, K AF GUPTA, RN LEE, KP MOSS, JN SUTTON, K TI VISCOUS SHOCK-LAYER SOLUTIONS WITH COUPLED RADIATION AND ABLATION FOR EARTH ENTRY SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Results are obtained for the forebody of a planetary exploration vehicle entering the Earth's atmosphere. A viscous shock-layer analysis is used assuming the flow to be laminar and in chemical equilibrium. Presented results include coupled radiation and ablation injection. This study further includes the effect of different transport and thermodynamic properties and radiation models. A Lewis number of 1.4 appears adequate for the radiation-dominated flows. Five velocities corresponding to different possible trajectory points at an altitude of 70 km have been further analyzed in detail. Sublimation and radiative equilibrium wall temperatures are employed for cases with and without coupled injection, respectively. For the cases analyzed here, the mass injection rates are small. However, the rates could become large if a lower altitude is used for aerobraking and/or the body size is increased. A comparison of the equilibrium results with finite-rate chemistry calculation shows the flowfield to be in chemical equilibrium. C1 VIGYAN RES ASSOCIATES INC,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665. RP GUPTA, RN (reprint author), NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 40 TC 17 Z9 18 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 MAR-APR PY 1992 VL 29 IS 2 BP 173 EP 181 DI 10.2514/3.26332 PG 9 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400005 ER PT J AU GNOFFO, PA PRICE, JM BRAUN, RD AF GNOFFO, PA PRICE, JM BRAUN, RD TI COMPUTATION OF NEAR-WAKE, AEROBRAKE FLOWFIELDS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SCHEMES AB Simulations of the near-wake flowfield behind three aerobrakes have been implemented with Program LAURA, an algorithm for obtaining the numerical solution to the governing equations for three-dimensional, viscous, hypersonic flows in chemical and thermal nonequilibrium. Emphasis is placed on understanding the conditions that are likely to cause the shear layer to impinge on a payload positioned behind the aerobrake. A linear relationship between shear-layer deflection angle and angle of attack (or lift-to-drag ratio) has been identified in several ground-based tests. A similar relation appears in the numerical simulations, though there is some evidence that deflection angles may increase somewhat due to the effects of gas chemistry. Shear-layer impingement can raise local heating levels a factor of 10 higher than levels present without impingement. C1 NASA,LANGLEY RES CTR,DIV SPACE SYST,VEHICLE ANAL BRANCH,HAMPTON,VA 23665. RP GNOFFO, PA (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 20 TC 16 Z9 16 U1 2 U2 3 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 MAR-APR PY 1992 VL 29 IS 2 BP 182 EP 189 DI 10.2514/3.26333 PG 8 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400006 ER PT J AU HENLINE, WD AF HENLINE, WD TI THERMAL PROTECTION ANALYSIS OF MARS-EARTH RETURN VEHICLES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB An analysis is performed to determine the aerothermodynamic heating and thermal protection materials requirements of a typical "fast" manned Mars mission. Entry conditions represent those consistent with an early manned mission hiving a total trip time of approximately 14-16 months. A coupled flowfield-radiation stagnation region heat transfer viscous shock layer (VSL) calculation was performed to ascertain the various shock layer heating mechanisms and the resultant surface heat fluxes for a generic shaped Mars/Earth return capsule. Computations were performed using the VSL computer code, RASLE. The ablation and thermal response of four different candidate ablating heat shield materials was determined using results from the RASLE code in conjunction with the detailed (one-dimensional) charring ablator-thermal response code CMA. Based on these results, the Earth return capsule thermal protection system (TPS) mass fraction was estimated for each material. A general conclusion is that attractive TPS mass fractions of 10-15% are possible with these candidate systems but that a vehicle and mission dependent choice must be made between heat shield total surface recession and initial TPS mass fraction. RP HENLINE, WD (reprint author), NASA,AMES RES CTR,THERMAL PROTECT MAT BRANCH,MOFFETT FIELD,CA 94035, USA. NR 29 TC 5 Z9 5 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 MAR-APR PY 1992 VL 29 IS 2 BP 198 EP 207 DI 10.2514/3.26335 PG 10 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400008 ER PT J AU HAMILTON, HH GREENE, FA WEILMUENSTER, KJ AF HAMILTON, HH GREENE, FA WEILMUENSTER, KJ TI COMPARISON OF HEATING CALCULATIONS WITH EXPERIMENTAL-DATA ON A MODIFIED SHUTTLE ORBITER SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Heating-rate calculations from an "engineering" code and a "benchmark" Navier-Stokes code are compared with experimental wind-tunnel data obtained on a "modified" 0.0075 scale Shuttle Orbiter at a Mach number of 6 and a freestream Reynolds number of 1.9 x 10(6)/m. Comparisons are presented along the windward symmetry plane, in a circumferential direction around the body, and along the wing leading edge at angles of attack of 30 and 40 deg. From these results, it is shown that both codes provide accurate predictions of the heating rate over most of the body, but because the run time for the engineering code is relatively short, it is an ideal tool for both parametric and design studies. RP HAMILTON, HH (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 13 TC 3 Z9 3 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 MAR-APR PY 1992 VL 29 IS 2 BP 208 EP 215 DI 10.2514/3.26336 PG 8 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400009 ER PT J AU MCRONALD, AD RANDOLPH, JE AF MCRONALD, AD RANDOLPH, JE TI HYPERSONIC MANEUVERING FOR AUGMENTING PLANETARY GRAVITY ASSIST SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB In a previous paper, the authors analyzed aeromaneuvers at Venus and Earth. In (his paper, they extend the study to Mars, examining the potential of aeroassist maneuvers at Mars for missions to the Sun and to Pluto, using a high lift/drag vehicle such as the waverider to perform an atmospheric fly-around of Mars, in order to rotate the planetocentric velocity vector, thus adding to the rather small rotation due to gravity alone. A fly-around in one direction or the other can place the aphelion or the perihelion of the resulting orbit at the Mars distance for missions toward the Sun or toward Pluto, respectively. The parameters of such maneuvers are given as a function of Earth launch velocity. It is found to be advantageous in terms of Earth launch velocity to perform two aeromaneuvers, e.g., one at Venus and then one at Mars. Some problems regarding the actual implementation of these aeromaneuvers are discussed. RP MCRONALD, AD (reprint author), CALTECH,JET PROP LAB,TECH STAFF,MS 301-165,PASADENA,CA 91109, USA. NR 9 TC 24 Z9 25 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 MAR-APR PY 1992 VL 29 IS 2 BP 216 EP 222 DI 10.2514/3.26337 PG 7 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400010 ER PT J AU RANDOLPH, JE MCRONALD, AD AF RANDOLPH, JE MCRONALD, AD TI SOLAR-SYSTEM FAST MISSION TRAJECTORIES USING AEROGRAVITY ASSIST SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Initial analyses of the aerogravity assist (AGA) delivery technique to solar system targets (and beyond) has been encouraging. Mission opportunities are introduced that do not exist with typical gravity assist trajectories and current launch capabilities. The technique has the most payoff for high-energy missions such as outer planet orbiters and flybys. The goal of this technique is to reduce the flight duration significantly and to eliminate propulsion for orbit insertion. The paper will discuss detailed analyses and parametric studies that consider launch opportunities for missions to the Sun, Saturn, Uranus, Neptune, and Pluto using AGA at Venus and Mars. RP RANDOLPH, JE (reprint author), CALTECH,JET PROP LAB,TECH STAFF,PASADENA,CA 91109, USA. NR 8 TC 13 Z9 14 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1992 VL 29 IS 2 BP 223 EP 232 DI 10.2514/3.26338 PG 10 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400011 ER PT J AU ANDERSON, LA HADDOCK, MH AF ANDERSON, LA HADDOCK, MH TI TETHERED ELEVATOR DESIGN FOR SPACE STATION SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper describes the conceptual engineering design of a space station elevator that operates on a 10-km tether spanning the distance between the space station and a tethered platform. The unmanned mobile structure provides access to residual gravity levels, remote servicing, and transportation to any point along the tether. Design requirements including torque and power requirements are discussed. A configuration is proposed including the robotics, drive mechanism, and power generation and transmission subsystems. Design emphasis is placed on the hooking/unhooking of the tether and the conception of a suitable capture and drive mechanism to interface with the tether to control elevator motion. A brief discussion of the decison matrix analysis is provided to indicate the method used to select the chosen tethered elevator and subsystem configurations. The tethered elevator design illustrates the uses of such a device for space station operations. C1 NASA,SHUTTLE THERMAL PROTECT SYST PROJECT OFF,KENNEDY SPACE CTR,FL 32899. RP ANDERSON, LA (reprint author), UNIV CENT FLORIDA,MECH & AEROSP ENGN,ORLANDO,FL 32816, USA. NR 13 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 MAR-APR PY 1992 VL 29 IS 2 BP 233 EP 238 DI 10.2514/3.26339 PG 6 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400012 ER PT J AU YANG, RJ CHANG, JLC KWAK, D AF YANG, RJ CHANG, JLC KWAK, D TI NAVIER-STOKES FLOW SIMULATION OF THE SPACE-SHUTTLE MAIN ENGINE HOT GAS MANIFOLD SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID IMPLICIT AB Incompressible viscous flow inside the turnaround duct, the fuel bowl, the transfer duct, and the racetrack of the Space Shuttle main engine hot gas manifold has been computed using the method of pseudocompressibility together with an implicit, approximate-factorization algorithm. A multiple-zone method is used to make solution of flows in complex geometries easy. A model that estimates the pressure loading for the shield and the injector post arrangement without solving the complex flowfield in the main injector region is proposed. The computed results show good qualitative agreement with experimental data. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP YANG, RJ (reprint author), ROCKWELL INT CORP,ROCKETDYNE DIV,TECH STAFF,CANOGA PK,CA 91303, USA. RI Yang, Ruey-Jen/A-1122-2009 OI Yang, Ruey-Jen/0000-0002-1958-0389 NR 10 TC 4 Z9 4 U1 0 U2 3 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 MAR-APR PY 1992 VL 29 IS 2 BP 253 EP 259 DI 10.2514/3.26342 PG 7 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400015 ER PT J AU PETRO, AJ AF PETRO, AJ TI TECHNIQUES FOR ORBITAL DEBRIS CONTROL SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper will summarize a range of techniques that have been proposed for controlling the growth of man-made debris in Earth orbit. Several techniques developed in studies at NASA Johnson Space Center will be described in detail. These techniques include the retrieval of inoperative satellites with an orbital maneuvering vehicle and self-disposal devices for satellites and upper stages. Self-disposal devices include propulsive deorbit motors and passive drag-augmentation devices. Concepts for sweeping small debris from the orbital environment will also be described. An evaluation of the technical feasibility and economic practicality of the various control methods will be summarized. In general, methods that prevent the accumulation of large debris objects were found to provide greater promise for control of the debris problem than methods of removing small debris particles. RP PETRO, AJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SYST DEFINIT BRANCH,ET2,HOUSTON,TX 77058, USA. NR 5 TC 5 Z9 5 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 MAR-APR PY 1992 VL 29 IS 2 BP 260 EP 263 DI 10.2514/3.26343 PG 4 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400016 ER PT J AU SCHENK, A PAPPA, RS AF SCHENK, A PAPPA, RS TI PRACTICAL ASPECTS OF ON-ORBIT MODAL IDENTIFICATION USING FREE-DECAY DATA SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper discusses practical aspects of performing on-orbit modal identification using time domain analysis of free-decay data. The effects of environmental constraints, structural characteristics, excitation, and sensing are reviewed. In a recent laboratory application, an on-orbit experiment is simulated using a limited number of excitation and measurement points. The identified modal parameters correlate well, though not uniquely, with those obtained in a complete modal survey. Practical difficulties in performing the correlation are illustrated. C1 NASA,LANGLEY RES CTR,SPACECRAFT DYNAM BRANCH,HAMPTON,VA 23665. RP SCHENK, A (reprint author), GERMAN AEROSP RES ESTAB,INST AEROELAST,BUNSENSTR 10,W-3400 GOTTINGEN,GERMANY. NR 17 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 MAR-APR PY 1992 VL 29 IS 2 BP 264 EP 270 DI 10.2514/3.26344 PG 7 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400017 ER PT J AU VENKATESWARAN, S WITTE, DW HUNT, LR AF VENKATESWARAN, S WITTE, DW HUNT, LR TI AXIAL-COMPRESSION CORNER FLOW WITH SHOCK IMPINGEMENT SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NASA,LANGLEY RES CTR,SUPERSON HYPERSON AERODYNAM BRANCH,HAMPTON,VA 23665. NASA,LANGLEY RES CTR,AEROTHERMAL LOADS BRANCH,HAMPTON,VA 23665. RP VENKATESWARAN, S (reprint author), LOCKHEED ENGN & SCI CO,INTEGRATED FLUID THERMAL STRUT RES,HAMPTON,VA 23666, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1992 VL 29 IS 2 BP 288 EP 289 PG 2 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400021 ER PT J AU LANDIS, GA LINNE, DL AF LANDIS, GA LINNE, DL TI ACETYLENE FUEL FROM ATMOSPHERIC CO2 ON MARS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note RP LANDIS, GA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 1992 VL 29 IS 2 BP 294 EP 296 DI 10.2514/3.26350 PG 3 WC Engineering, Aerospace SC Engineering GA HM954 UT WOS:A1992HM95400024 ER PT J AU GINGOLD, H SHE, J ZORUMSKI, WE AF GINGOLD, H SHE, J ZORUMSKI, WE TI REFLECTION OF SOUND-WAVES BY SOUND-SPEED INHOMOGENEITIES SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID PROPAGATION AB An analysis is given of the influence of the rate of change of sound speed on reflection and transmission in a perfect gas. Asymptotic formulas, valid for both low and high frequencies, are developed to compute the reflection and transmission coefficients for one-dimensional waves propagating through variable-speed layers. The sound speed may have a discontinuous first derivative. It is shown that local reflection effects are proportional to the square of the derivative of the logarithm of the sound speed. The method predicts reflections for gradually varying sound-speed profiles having continuous derivatives of all orders. In the special case where the sound speed is a piecewise linear function, the general method produces an exact solution in addition to the asymptotic formulas. This exact solution is valid for arbitrarily large sound-speed gradient and reduces to the classical result for discontinuous sound speed in the limit of an infinite gradient over an infinitesimal distance. The exact solution produces an effective numerical method when an arbitrary sound-speed profile is modeled by a mixed sequence of discontinuities and ramp functions. C1 LANGLEY RES CTR,DIV ACOUST,HAMPTON,VA 23665. RP GINGOLD, H (reprint author), W VIRGINIA UNIV,DEPT MATH,MORGANTOWN,WV 26506, USA. NR 15 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 1992 VL 91 IS 3 BP 1262 EP 1269 DI 10.1121/1.402509 PG 8 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA HH965 UT WOS:A1992HH96500005 ER PT J AU YOST, WT CANTRELL, JH KUSHNICK, PW AF YOST, WT CANTRELL, JH KUSHNICK, PW TI FUNDAMENTAL-ASPECTS OF PULSE PHASE-LOCKED LOOP TECHNOLOGY-BASED METHODS FOR MEASUREMENT OF ULTRASONIC VELOCITY SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB A new instrument based on a constant frequency pulse phase-locked loop concept has been developed to accurately measure the ultrasonic phase velocity in condensed matter. Measurements of the sound velocity in ultrapure water are reported in which both damped and undamped transducers are used with the instrument together with reflectors of various thicknesses placed in the sound propagation path. An analysis of measurements made with the new instrument and similar measurements, taken under identical experimental conditions, using a popular variable frequency pulsed-phase-locked loop instrument is reported. Uncertainties in both measurement systems are analyzed and discussed. A method for measuring inherent phase shifts, not addressed by previous investigators, within the variable frequency pulsed phase-locked loop system and a derivation of the equations that govern the overall use of variable frequency systems using phase-sensitive comparisons are presented. The effects of a finite pulse length on the measurements of phase velocity in dispersive media are addressed in detail. C1 CONTINUOUS ELECTRON BEAM ACCELERATOR FACIL,NEWPORT NEWS,VA 23606. RP YOST, WT (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 231,HAMPTON,VA 23665, USA. NR 25 TC 10 Z9 10 U1 1 U2 3 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 MAR PY 1992 VL 91 IS 3 BP 1456 EP 1468 DI 10.1121/1.402477 PG 13 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA HH965 UT WOS:A1992HH96500027 PM 1564190 ER PT J AU BOUMSELLEK, S ALAJAJIAN, SH CHUTJIAN, A AF BOUMSELLEK, S ALAJAJIAN, SH CHUTJIAN, A TI NEGATIVE-ION FORMATION IN THE EXPLOSIVES RDX, PETN, AND TNT BY USING THE REVERSAL ELECTRON-ATTACHMENT DETECTION TECHNIQUE SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID TRAP MASS-SPECTROMETER; CROSS-SECTIONS; ENERGIES; CCL4 AB First results of a beam-beam, single-collision study of negative-ion mass spectra produced by attachment of zero-energy electrons to the molecules of the explosives RDX, PETN, and TNT are presented. The technique used is reversal electron attachment detection (READ) wherein the zero-energy electrons are produced by focusing an intense electron beam into a shaped electrostatic field which reverses the trajectory of electrons. The target beam is introduced at the reversal point, and attachment occurs because the electrons have essentially zero longitudinal and radial velocity. The READ technique is used to obtain the "signature" of molecular ion formation and/or fragmentation for each explosive. Present data are compared with results from atmospheric-pressure ionization and negative-ion chemical ionization methods. C1 CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109. NR 21 TC 34 Z9 34 U1 2 U2 17 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD MAR PY 1992 VL 3 IS 3 BP 243 EP 247 DI 10.1016/1044-0305(92)87008-M PG 5 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA HM604 UT WOS:A1992HM60400008 PM 24242947 ER PT J AU KUMAR, BVKV JUDAY, RD RAJAN, PK AF KUMAR, BVKV JUDAY, RD RAJAN, PK TI SATURATED FILTERS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID PHASE-ONLY FILTERS; NOISE RATIO; SIGNAL AB Most previous research into the design of correlation filters considered only input noise and filter spatial light modulators (SLM's) of an implicitly assumed infinite contrast ratio. We introduce a signal-to-noise ratio that also includes correlation-detector noise and finite contrast SLM's. Filters maximizing this signal-to-noise ratio exhibit saturation at some frequencies and are called saturated filters. We accommodate SLM's whose amplitude has a finite maximum and a nonzero minimum. We give algorithms for optimum saturated complex- and real-valued filters. Previous results are reproduced as various limiting cases. The phase-only filter and the binary phase-only filter are limiting cases for large detector noise with, respectively, complex and real modulators. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. TENNESSEE TECHNOL UNIV,COOKEVILLE,TN 38505. RP KUMAR, BVKV (reprint author), CARNEGIE MELLON UNIV,PITTSBURGH,PA 15213, USA. NR 11 TC 14 Z9 14 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD MAR PY 1992 VL 9 IS 3 BP 405 EP 412 DI 10.1364/JOSAA.9.000405 PG 8 WC Optics SC Optics GA HE745 UT WOS:A1992HE74500006 ER PT J AU BERENDS, RW MALEKI, L AF BERENDS, RW MALEKI, L TI HYPERFINE-STRUCTURE AND ISOTOPE SHIFTS OF TRANSITIONS IN NEUTRAL AND SINGLY IONIZED YTTERBIUM SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID GROUND-STATE; SPECTROSCOPY; LASER AB The hyperfine coupling coefficients and isotope shifts associated with the Yb+ 6(2)P3/2-degrees, Yb 73S1, Yb 6(1)P1-degrees, and Yb 6(1)D2 states were investigated by Doppler-free saturated absorption laser spectroscopy in an unenriched Yb hollow-cathode discharge. The hyperfine coefficients determined in this experiment are as follows: for the Yb+ 6(2)P3/2-degrees state, 171A = 0.877(20), 173A = -0.245(10), and 173B = 1.460(50); for the 7(3)S1 state, 171A = 6.81(10), 173A = -1.879(10), and 173B = -0.003(18); for the Yb 6(1)D2 state, 171A = -1.573(8), 173A = 0.439(2), and 173B = 0.153(10) GHz. RP BERENDS, RW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 28 TC 33 Z9 33 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 1992 VL 9 IS 3 BP 332 EP 338 DI 10.1364/JOSAB.9.000332 PG 7 WC Optics SC Optics GA HG733 UT WOS:A1992HG73300003 ER PT J AU WALIKAINEN, D AF WALIKAINEN, D TI ONE GHZ LEAKY SAW VELOCITY OF METAL LAYERS AND BILAYERS EVAPORATED ONTO FUSED QUARTZ SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID THICKNESS MEASUREMENT; ACOUSTIC MICROSCOPE; THIN-FILMS; INTERPHASE AB An acoustic microscope operating at 1 GHz was used to determine the surface acoustic wave velocities upsilon of thin film metal layers and metal bilayers deposited onto fused quartz. V(0)'s influence was reduced by gating. This produced a calibrated accuracy of 3%. A program was constructed from the explicitly solved 6 x 6 theoretical determinant. Single film thicknesses were decided upon by using this theory to produce a upsilon equal to a standard. Since the single film upsilon's were linear with respect to their thickness, half the single film thicknesses were used for the bilayered films. The velocities for these bilayered films agreed with theory. This experimentally confirms the theoretical technique used here to examine bilayered systems, or a prototype composite interphase. No discrepancy was seen for gold films as others have reported. V(z) seemed insensitive to the formation of intermetallics or CuO. Some annealed and unannealed platinum films did not change the upsilon from that of fused quartz. Two platinum films whose upsilon's were in agreement with theory peeled off with the tape test. RP WALIKAINEN, D (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 16 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAR-APR PY 1992 VL 10 IS 2 BP 290 EP 294 DI 10.1116/1.578078 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA HK010 UT WOS:A1992HK01000005 ER PT J AU LATHROP, RG PETERSON, DL AF LATHROP, RG PETERSON, DL TI IDENTIFYING STRUCTURAL SELF-SIMILARITY IN MOUNTAINOUS LANDSCAPES SO LANDSCAPE ECOLOGY LA English DT Article DE MODEL; FRACTALS; LANDSCAPE ECOLOGY; ECOSYSTEM AB Digital elevation model data were used to partition a mountainous landscape (northwester Montana, USA) into watershed/hillslope terrain units at several different spatial scales. Fractal analysis of the perimeter to area relationships of the resulting partition polygons identified statistical self-similarity across a range of spatial scales (approximately four orders of magnitude in partition area). The fractal dimension was higher for a relatively complex fluvially-dominated terrain than for a structurally simpler glacially-dominated terrain (1.23 vs. 1.02, respectively). The structural self-similarity exhibited by this landscape has direct implications in scaling up ecosystem process models for landscape to regional simulations. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP LATHROP, RG (reprint author), RUTGERS STATE UNIV, COOK COLL, DEPT ENVIRONM RESOURCES, NEW BRUNSWICK, NJ 08903 USA. NR 0 TC 6 Z9 7 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0921-2973 J9 LANDSCAPE ECOL JI Landsc. Ecol. PD MAR PY 1992 VL 6 IS 4 BP 233 EP 238 DI 10.1007/BF00129701 PG 6 WC Ecology; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA HK278 UT WOS:A1992HK27800002 ER PT J AU KELLER, LP CLARK, JC LEWIS, CF MOORE, CB AF KELLER, LP CLARK, JC LEWIS, CF MOORE, CB TI MARALINGA, A METAMORPHOSED CARBONACEOUS CHONDRITE FOUND IN AUSTRALIA SO METEORITICS LA English DT Article ID WESTERN AUSTRALIA; NULLARBOR REGION; METEORITES; FINDS AB The Maralinga meteorite was found near the village of Maralinga, South Australia (30-degrees-18'S, 131-degrees-16'E) in 1974, but was not recognized as a meteorite until 1989. One weathered individual was recovered with a total mass of 3.38 kg. The bulk composition and petrography of Maralinga indicate that it is a metamorphosed (petrographic type 4) carbonaceous chondrite with major similarities to the Vigarano-subtype. However, recent trace element data from the literature suggest that Maralinga should be included with the CK (Karoonda-type) carbonaceous chondrites. We classify Maralinga as an anomalous CK4 chondrite because of its abundant chondrules and refractory inclusions relative to other known members of the CK group. Maralinga contains homogeneous silicates, including Ni-bearing olivines (Fa34), high-Ca clinopyroxene, and rare orthopyroxene. Plagioclase is chemically heterogeneous and falls into two distinct compositional groups one of approximately An20 and an approximately An80 group. Highly oxidizing conditions during metamorphism of Maralinga are indicated by the abundance of magnetite and the paucity of Fe-Ni metal. C1 ARIZONA STATE UNIV,DEPT CHEM,TEMPE,AZ 85287. ARIZONA STATE UNIV,CTR METEORITE STUDIES,TEMPE,AZ 85287. RP KELLER, LP (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN14,HOUSTON,TX 77058, USA. NR 13 TC 22 Z9 22 U1 0 U2 3 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAR PY 1992 VL 27 IS 1 BP 87 EP 91 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HN056 UT WOS:A1992HN05600009 ER PT J AU TREIMAN, AH AF TREIMAN, AH TI FALL DAYS OF THE SNC METEORITES - EVIDENCE FOR AN SNC METEOROID STREAM, AND A COMMON SITE OF ORIGIN SO METEORITICS LA English DT Article ID SHERGOTTITES; CHONDRITE; EVOLUTION; ORBIT; MARS AB Four of the SNC meteorites of putative Martian origin are falls. Two of these fell on October 3: Chassigny in 1815 and Zagami in 1962. The probability of this coincidence arising from random fall days is approximately 1 in 60. If this coincidence is not the result of chance, it suggests that some of the SNC meteorites are derived from a meteoroid stream. In that Chassigny and Zagami span nearly the full range of SNC lithologies and histories, the coincidence of fall days is consistent with suggestions that all of the SNCs came from a single site (impact crater) on their parent planet. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP TREIMAN, AH (reprint author), NATL RES COUNCIL,SN-21,HOUSTON,TX 77058, USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAR PY 1992 VL 27 IS 1 BP 93 EP 95 PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HN056 UT WOS:A1992HN05600010 ER PT J AU HUGHES, MW DESOTO, EY SHERIF, YS AF HUGHES, MW DESOTO, EY SHERIF, YS TI ON SOFTWARE STANDARDS SO MICROELECTRONICS AND RELIABILITY LA English DT Article AB This paper examines the Jet Propulsion Laboratory (JPL) Software Management Standard, D-4000, and the Department of Defense DOD-STD-2167A, Military Standard Defense System Software Development. The paper identifies the unique requirements of each standard, their relationships and/or their specific emphasis. C1 CALIF STATE UNIV FULLERTON,FULLERTON,CA 92634. RP HUGHES, MW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 5 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 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD MAR PY 1992 VL 32 IS 3 BP 369 EP 405 DI 10.1016/0026-2714(92)90069-W PG 37 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA GY717 UT WOS:A1992GY71700013 ER PT J AU SHERIF, YS KELLY, JC AF SHERIF, YS KELLY, JC TI IMPROVING SOFTWARE QUALITY THROUGH FORMAL INSPECTIONS SO MICROELECTRONICS AND RELIABILITY LA English DT Article AB The software inspection process was created for the dual purpose of improving software quality and increasing programmers' productivity. This paper puts forward formal inspections as an alternative to and a better method than technical walkthroughs in the software life cycle reviewing process. Examples of benefits gained in the development of defect-free software by utilizing formal inspections are cited. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP SHERIF, YS (reprint author), CALIF STATE UNIV FULLERTON,FULLERTON,CA 92634, USA. NR 29 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 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD MAR PY 1992 VL 32 IS 3 BP 423 EP 431 DI 10.1016/0026-2714(92)90072-S PG 9 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA GY717 UT WOS:A1992GY71700016 ER PT J AU SUI, CH LAU, KM AF SUI, CH LAU, KM TI MULTISCALE PHENOMENA IN THE TROPICAL ATMOSPHERE OVER THE WESTERN PACIFIC SO MONTHLY WEATHER REVIEW LA English DT Article ID NORTHERN HEMISPHERE SUMMER; 40-50 DAY OSCILLATIONS; AIR-SEA INTERACTION; INTRASEASONAL OSCILLATIONS; KELVIN WAVE; TIME SCALE; DYNAMICS; VARIABILITY; CLUSTERS; MONSOON AB Multiscale variabilities in the atmosphere over the tropical western Pacific during the 1979 Northern Hemisphere winter are studied with an aim at identifying possible interactions between phenomena of different spatial and temporal scales. Based on the convection-index information derived from satellite measurements, two intraseasonal oscillations (ISOs) are identified within the equatorial belt between 0-degrees and 10-degrees-S in the analyzed period. The two ISOs, accompanied by both rotational and divergent circulations, propagate eastward from the Indian Ocean to the western Pacific. Over the warm pool in the western Pacific, the ISOs develop into quasi-stationary systems with an enhanced rotational circulation characterized by a strong westerly jet in the lower troposphere. The ISOs appear to interact with a number of regional- and synoptic-scale phenomena in the maritime continent and western Pacific region. For example, the onset of the monsoon coincides with the arrival of the first ISO at northern Australian region (140-degrees-E) in late December. The passage of ISOs in the monsoon flow are also associated with surface westerly wind outbreaks. On shorter time scales (< 10 days), the ISOs appear to provide a favorable condition over the warm ocean for the development of 2-4-day disturbances that further organize mesoscale cloud clusters. In addition, the diurnal cycle provides another important forcing mechanism modulating cloud clusters, particularly over the maritime continents. There appears to be an inverse relationship between diurnal cycle and intraseasonal disturbances (greater-than-or-equal-to 10 days) over the maritime continent; that is, periods of active intraseasonal variabilities are characterized by diminished diurnal cycles and vice versa. The possible role of these multiscale processes in the coupled ocean-atmosphere system is discussed. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RP SUI, CH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOCIAT,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012; OI Lau, William /0000-0002-3587-3691; SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 42 TC 109 Z9 111 U1 1 U2 9 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 MAR PY 1992 VL 120 IS 3 BP 407 EP 430 DI 10.1175/1520-0493(1992)120<0407:MPITTA>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HG832 UT WOS:A1992HG83200003 ER PT J AU SHEPHERD, KP AF SHEPHERD, KP TI AIRCRAFT NOISE AND AIRPORT CAPACITY SO NOISE CONTROL ENGINEERING JOURNAL LA English DT Article AB Current predictions are forecasting a doubling of the number of aircraft passengers within the next decade. It has been suggested that aircraft noise provides a major impediment to the growth of existing airports and the construction of new ones. Current aircraft noise certification requirements, which limit the noise levels of new transport aircraft, allow heavier aircraft to generate higher noise levels. In contrast, noise limits at some individual airports are independent of aircraft weight. Restrictions which favor smaller, more quiet aircraft prompt a question regarding their impact on capacity. Although they obviously achieve their objective of eliminating all but the most quiet aircraft, what are the implications for capacity and noise impact of many operators of small aircraft compared to fewer operations of large aircraft? This paper presents a simple analysis of the relationships between aircraft size, noise levels, and the number of aircraft events and noise exposure. RP SHEPHERD, KP (reprint author), NASA,LANGLEY RES CTR,MS 463,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 1 U2 2 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 MAR-APR PY 1992 VL 38 IS 2 BP 67 EP 71 DI 10.3397/1.2827807 PG 5 WC Acoustics; Engineering, Multidisciplinary SC Acoustics; Engineering GA JE037 UT WOS:A1992JE03700003 ER PT J AU SAKURAI, H RAMSEY, BD AF SAKURAI, H RAMSEY, BD TI DEPENDENCE OF ENERGY RESOLUTION ON ANODE DIAMETER IN XENON PROPORTIONAL-COUNTERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The characteristics of a conventional cylindrical geometry proportional counter with different anode wire diameters from 12.5-mu-m to 100-mu-m were investigated for both pure xenon gas and xenon +5% methane gas mixtures at 1 atm. With pure xenon gas the energy resolution with 12.5-mu-m and 100-mu-m anodes were 7.0% and 8.1% for 22 keV X-rays, respectively. From calculations of the Townsend ionization coefficient it is shown that proportional counters with thinner anode wires operate at stronger reduced electric fields than those with thicker anode wires. It is suggested that this is the fundamental reason for the improvement in energy resolution observed as the anode diameter is decreased. RP SAKURAI, H (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 14 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 1992 VL 313 IS 1-2 BP 155 EP 160 DI 10.1016/0168-9002(92)90092-I PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HG343 UT WOS:A1992HG34300014 ER PT J AU SINGH, JJ EFTEKHARI, A AF SINGH, JJ EFTEKHARI, A TI FREE-VOLUME MODEL FOR MOLECULAR-WEIGHTS OF POLYMERS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID POSITRON-ANNIHILATION AB A free volume model has been developed for determining molecular weights of linear polymers. It is based on the size of free volume cells in two geometries of poly (arylene ether ketone)s. Free volume cell sizes in test samples were measured using positron lifetime spectroscopy. The molecular weights computed from free volume cell sizes are in good agreement with the values measured by gel permeation chromatography, with a low angle laser light scattering photometer as the detector. The model has been further tested on two atactic polystyrene samples, where it predicted the ratio of their molecular weights with reasonable accuracy. C1 HAMPTON UNIV,HAMPTON,VA 23668. RP SINGH, JJ (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 13 TC 13 Z9 13 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 1992 VL 63 IS 4 BP 477 EP 483 DI 10.1016/0168-583X(92)95221-C PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA HN168 UT WOS:A1992HN16800015 ER PT J AU TAKAHASHI, T TANS, PP FUNG, I AF TAKAHASHI, T TANS, PP FUNG, I TI BALANCING THE BUDGET - CARBON-DIOXIDE SOURCES AND SINKS, AND THE EFFECTS OF INDUSTRY SO OCEANUS LA English DT Article C1 NOAA,CLIMATE MONITORING & DIAGNOST LAB,BOULDER,CO 80303. NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP TAKAHASHI, T (reprint author), COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964, USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU WOODS HOLE OCEANOGRAPHIC INST PI WOODS HOLE PA OCEANUS MAGAZINE, WOODS HOLE, MA 02543 SN 0029-8182 J9 OCEANUS JI Oceanus PD SPR PY 1992 VL 35 IS 1 BP 18 EP 28 PG 11 WC Oceanography SC Oceanography GA HT663 UT WOS:A1992HT66300005 ER PT J AU REMINGTON, RW JOHNSTON, JC YANTIS, S AF REMINGTON, RW JOHNSTON, JC YANTIS, S TI INVOLUNTARY ATTENTIONAL CAPTURE BY ABRUPT ONSETS SO PERCEPTION & PSYCHOPHYSICS LA English DT Article ID VISUAL-ATTENTION; SELECTIVE ATTENTION; MOVING ATTENTION; FIELD; SEARCH; AUTOMATICITY; SENSITIVITY; INFORMATION; ALLOCATION; MOVEMENTS AB The extent to which brief abrupt-onset visual stimuli involuntarily capture spatial attention was examined in five experiments. The paradigm used was intended to maximize the opportunity and incentive for subjects to ignore abrupt-onset distractor stimuli in nontarget locations. Subjects made a speeded two-choice response to a target letter appearing in one of four boxes. An abrupt-onset visual stimulus, easily discriminable from the target, was flashed briefly prior to the presentation of a target. In separate blocks, the flash stimulus marked the box in which the target would subsequently appear (SAME), a different box (DIFF), fixation (CENTER), or all four boxes (ALL). Prior to each block, subjects were informed of the flash-target relationship. In all five experiments, response time was elevated in the DIFF, CENTER, and ALL conditions. The interference effect was larger for the DIFF condition and persisted for longer flash-target SOAs, These results suggest that, under appropriate conditions, spatial attention can be involuntarily drawn to abrupt-onset events despite the intention of subjects' to ignore them. C1 JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. RP REMINGTON, RW (reprint author), NASA,AMES RES CTR,MS 262-2,MOFFETT FIELD,CA 94035, USA. RI Yantis, Steven/A-7488-2009 FU NIMH NIH HHS [R01-MH43924] NR 36 TC 245 Z9 250 U1 1 U2 15 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0031-5117 J9 PERCEPT PSYCHOPHYS JI Percept. Psychophys. PD MAR PY 1992 VL 51 IS 3 BP 279 EP 290 DI 10.3758/BF03212254 PG 12 WC Psychology; Psychology, Experimental SC Psychology GA HH655 UT WOS:A1992HH65500008 PM 1561053 ER PT J AU ORIENT, OJ MARTUS, KE CHUTJIAN, A MURAD, E AF ORIENT, OJ MARTUS, KE CHUTJIAN, A MURAD, E TI RECOMBINATION OF 5-EV O(P-3) ATOMS WITH SURFACE-ADSORBED NO - SPECTRA AND THEIR DEPENDENCE ON SURFACE MATERIAL AND TEMPERATURE SO PHYSICAL REVIEW A LA English DT Article ID SHUTTLE GLOW; O(3P) ATOMS AB Recombination spectra are measured in the wavelength range 300-850 nm resulting from collisions of 5-eV O(3P) atoms with NO adsorbed on MgF2, Ni, and Ti surfaces. The dependence of the chemiluminescence intensity on surface temperature (240-340 K) is measured, and activation energies for desorption of the physisorbed NO obtained. Activation energies as a function of wavelength for each material are also reported. It is found that, with minor variations, the recombination spectra are similar for the three surfaces, and that the emitter is very likely electronically excited NO2. All three materials exhibit a greater tendency to emit at the lower temperatures. MgF2 has the greatest tendency to chemiluminesce, followed by Ni then Ti. Also, the activation energies for NO desorption are similar for the surfaces, and are independent of emission wavelength. The results are interpreted as a single mechanism of removal, with increasing T, of physisorbed NO from saturated surfaces of different coverage. C1 PHILLIPS LAB, WSSI, BEDFORD, MA 01731 USA. RP ORIENT, OJ (reprint author), CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 32 TC 21 Z9 21 U1 0 U2 0 PU AMER 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 MAR 1 PY 1992 VL 45 IS 5 BP 2998 EP 3003 DI 10.1103/PhysRevA.45.2998 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA HH617 UT WOS:A1992HH61700049 ER PT J AU YEH, NC REED, DS JIANG, W KRIPLANI, U HOLTZBERG, F GUPTA, A HUNT, BD VASQUEZ, RP FOOTE, MC BAJUK, L AF YEH, NC REED, DS JIANG, W KRIPLANI, U HOLTZBERG, F GUPTA, A HUNT, BD VASQUEZ, RP FOOTE, MC BAJUK, L TI SCALING OF VORTEX TRANSPORT-PROPERTIES IN HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID RESISTIVE TRANSITION; EPITAXIAL-FILMS; FLUX LIQUIDS; LATTICE; YBA2CU3O7-DELTA; ENHANCEMENT AB Using both dc and low-frequency-ac (10-10(5) Hz) transport measurements in low magnetic fields (0-6.3 kOe), we find that the vortex transport properties of YBa2Cu2.98Au0.02Ox (x = 6.97 +/- 0.02) single crystals are consistent with a three-dimensional second-order vortex-solid melting transition, with a static exponent v = 0.9 +/- 0.2, a dynamic exponent z = 2.0 +/- 0.2, and a characteristic current-density exponent mu = 0.5 +/- 0.1. In contrast, transport properties of epitaxial films generally agree with the Ambegaokar-Halperin model. C1 IBM CORP,THOMAS J WATSON RES CTR,DIV RES,YORKTOWN HTS,NY 10598. CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP YEH, NC (reprint author), CALTECH,DEPT PHYS,PASADENA,CA 91125, USA. NR 28 TC 38 Z9 38 U1 0 U2 4 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 MAR 1 PY 1992 VL 45 IS 10 BP 5654 EP 5658 DI 10.1103/PhysRevB.45.5654 PG 5 WC Physics, Condensed Matter SC Physics GA HJ689 UT WOS:A1992HJ68900060 ER PT J AU SAVOLAINEN, V CANUTO, VM SCHILLING, O AF SAVOLAINEN, V CANUTO, VM SCHILLING, O TI PENETRATIVE CONVECTION - PARAMETRIZED EXPRESSION FOR THE GROWTH-RATES SO PHYSICS OF FLUIDS A-FLUID DYNAMICS LA English DT Note AB The equations determining the linear growth rate omega characterizing a convectively unstable fluid with Rayleigh number R(u) bounded below by an impenetrable free boundary and above by a convectively stable fluid with Rayleigh number R(s), are solved numerically. Using the analytical Rayleigh-Benard growth rate omega(RB) as a convenient functional form, it is possible to fit the numerical values for omega if the vertical wave number k(z) = n-pi and the Rayleigh number R(RB) are taken to be functions of R(s), R(u), and the horizontal wave number k perpendicular-to, rather than n = integer as in the Rayleigh-Bernard case. In addition, contrary to Rayleigh-Benard convection, in which the critical Rayleigh number is fixed (R(RB)CR = 657.5), it is found that R(u)cr is variable in the presence of a stable layer, i.e., it depends on R(s). Specifically, for R(s) < 6300, R(u)cr < R(RB)cr so that the stable fluid hastens the onset of convection; on the other hand, when R(s) > 6300, R(u)cr > R(RB)cr so that the system becomes more stable. C1 COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. RP SAVOLAINEN, V (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. OI Schilling, Oleg/0000-0002-0623-2940 NR 13 TC 2 Z9 2 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8213 J9 PHYS FLUIDS A-FLUID PD MAR PY 1992 VL 4 IS 3 BP 626 EP 629 DI 10.1063/1.858278 PG 4 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA HE350 UT WOS:A1992HE35000016 ER PT J AU YOON, PH WU, CS MANDT, ME AF YOON, PH WU, CS MANDT, ME TI ION HEATING BY KINETIC CROSS-FIELD STREAMING INSTABILITY DUE TO REFLECTED IONS AT A QUASI-PERPENDICULAR SHOCK SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID PERPENDICULAR BOW SHOCK; MODIFIED 2-STREAM INSTABILITY; ELECTROMAGNETIC INSTABILITIES; GYRATING IONS; SIMULATION; PLASMAS AB The present paper shows that the reflected ion at a supercritical quasiperpendicular shock wave can excite a purely growing m9de propagating parallel to the ambient magnetic field (k parallel-to B0). To discuss the ion heating by such an unstable mode, the self-consistent quasilinear kinetic equation is solved with the assumption that the present purely growing mode is the dominant unstable mode in the system. In the quasilinear analysis of the instability, two particular cases are considered-the case of low initial ion beta [beta(i)(0) = 0.1 ] and that of a high initial ion beta [beta(i)(0) = 1]. For each case of low and high initial betas, two values of initial turbulence level are used. One corresponds to delta-B2(0)/B0(2) = 0.1 and the other corresponding to delta-B2L(0)/B0(2) = 0.1. It is shown that for both low and high beta cases, the ion heating at the shock becomes more efficient for a higher value of delta-B2(0)/B0(2). C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP YOON, PH (reprint author), UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLLEGE PK,MD 20742, USA. RI Yoon, Peter/E-2395-2013 NR 22 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD MAR PY 1992 VL 4 IS 3 BP 719 EP 729 DI 10.1063/1.860270 PG 11 WC Physics, Fluids & Plasmas SC Physics GA HF908 UT WOS:A1992HF90800027 ER PT J AU SULZMAN, FM FERRARO, JS FULLER, CA MOOREEDE, MC KLIMOVITSKY, V MAGEDOV, V ALPATOV, AM AF SULZMAN, FM FERRARO, JS FULLER, CA MOOREEDE, MC KLIMOVITSKY, V MAGEDOV, V ALPATOV, AM TI THERMOREGULATORY RESPONSES OF RHESUS-MONKEYS DURING SPACEFLIGHT SO PHYSIOLOGY & BEHAVIOR LA English DT Article DE AXILLARY TEMPERATURE; CIRCADIAN RHYTHMS; MACACA-MULATTA; MICROGRAVITY; SKIN TEMPERATURE; ACTIVITY ID CIRCADIAN-RHYTHMS AB This study examines the activity, axillary temperature (T(ax)), and ankle skin temperature (T(sk)) of two male Rhesus monkeys exposed to microgravity in space. The animals were flown on a Soviet biosatellite mission (COSMOS 1514). Measurements on the flight animals, as well as synchronous flight controls, were performed in the Soviet Union. Additional control studies were performed in the United States to examine the possible role of metabolic heat production in the T(ax) response observed during the spaceflight. All monkeys were exposed to a 24-h light-dark cycle (LD 16:8) throughout these studies. During weightlessness, T(ax) in both flight animals was lower than on earth. The largest difference (0.75-degrees-C) occurred during the night. There was a reduction in mean heart rate and T(sk) during flight. This suggests a reduction in both heat loss and metabolic rate during spaceflight. Although the circadian rhythms in all variables were present during flight, some differences were noted. For example, the amplitude of the rhythms in T(sk) and activity were attenuated. Furthermore, the T(ax) and activity rhythms did not have precise 24.0 hour periods and may have been externally desynchronized from the 24-h LD cycle. These data suggest a weakening of the coupling between the internal circadian pacemaker and the external LD synchronizer. C1 SO ILLINOIS UNIV,SCH MED,DEPT PHYSIOL,CARBONDALE,IL 62901. NASA,DIV LIFE SCI,WASHINGTON,DC 20546. UNIV CALIF DAVIS,DEPT ANIM PHYSIOL,DAVIS,CA 95616. INST CIRCADIAN PHYSIOL,BOSTON,MA 02215. UNIV CALIF DAVIS,CALIF PRIMATE RES CTR,DAVIS,CA 95616. INST BIOMED PROBLEMS,MOSCOW,USSR. NR 22 TC 14 Z9 16 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0031-9384 J9 PHYSIOL BEHAV JI Physiol. Behav. PD MAR PY 1992 VL 51 IS 3 BP 585 EP 591 DI 10.1016/0031-9384(92)90184-4 PG 7 WC Psychology, Biological; Behavioral Sciences SC Psychology; Behavioral Sciences GA HN239 UT WOS:A1992HN23900022 PM 1523235 ER PT J AU STARBIRD, M STARBIRD, T AF STARBIRD, M STARBIRD, T TI REQUIRED REDUNDANCY IN THE REPRESENTATION OF REALS SO PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY LA English DT Article DE AMBIGUOUS NUMBERS; REDUNDANT REPRESENTATIONS AB Redundancy in decimal-like representations of reals cannot be avoided. It is proved here that if {A(i)}i = 0, 1, 2, ... is a countable collection of countable (or finite) sets of reals such that for each real x there are a(i) is-an-element-of A(i) with [GRAPHICS] then there is a dense subset of reals with redundant representations; that is, there is a dense set C of R such that for each x in C, x = SIGMA(i = 0) infinity a(i) and x = SIGMA(i = 0) infinity b(i) with a(i), b(i) in A(i), but a(i) not-equal-t- b(i) for some i. Petkovsek [1] proved a similar result under the added assumption that every sum of the form SIGMA(i = 0) infinity a(i) with a(i) is-an-element-of A(i) converges. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP STARBIRD, M (reprint author), UNIV TEXAS,DEPT MATH,AUSTIN,TX 78712, USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0002-9939 J9 P AM MATH SOC JI Proc. Amer. Math. Soc. PD MAR PY 1992 VL 114 IS 3 BP 769 EP 774 DI 10.2307/2159403 PG 6 WC Mathematics, Applied; Mathematics SC Mathematics GA HH836 UT WOS:A1992HH83600031 ER PT J AU GEZARI, DY FOLZ, WC WOODS, LA VAROSI, F AF GEZARI, DY FOLZ, WC WOODS, LA VAROSI, F TI A 5-18 MU-M ARRAY CAMERA FOR HIGH-BACKGROUND ASTRONOMICAL IMAGING SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article AB A new infrared array camera system using a Hughes/SBRC 58 X 62 pixel hybrid Si:Ga array detector has been successfully applied to high-background 5-18-mu-m astronomical imaging observations. The off-axis reflective optical system minimizes thermal background loading and produces diffraction-limited images with negligible spatial distortion. The noise equivalent flux density (NEFD) of the camera at 10-mu-m on the 3.0-m NASA/Infrared Telescope Facility with broadband (DELTA-lambda/lambda = 0.1) interference filters and 0.26 arcsec pixel is NEFD = 0.01 Jy min-1/2 pixel-1 (1-sigma), and it operates at a frame rate of 30 Hz with no compromise in observational efficiency. The electronic and optical design of the camera, its photometric characteristics, examples of observational results, and techniques for successful array imaging in a high-background astronomical application are discussed. RP GEZARI, DY (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INFRARED ASTROPHYS BRANCH,CODE 685,GREENBELT,MD 20771, USA. NR 29 TC 18 Z9 18 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 MAR PY 1992 VL 104 IS 673 BP 191 EP 203 DI 10.1086/132978 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK944 UT WOS:A1992HK94400006 ER PT J AU RIEHLE, JR MANN, DH PETEET, DM ENGSTROM, DR BREW, DA MEYER, CE AF RIEHLE, JR MANN, DH PETEET, DM ENGSTROM, DR BREW, DA MEYER, CE TI THE MOUNT EDGECUMBE TEPHRA DEPOSITS, A MARKER HORIZON IN SOUTHEASTERN ALASKA NEAR THE PLEISTOCENE HOLOCENE BOUNDARY SO QUATERNARY RESEARCH LA English DT Article ID ASH C1 UNIV WASHINGTON,QUATERNARY RES CTR,SEATTLE,WA 98195. UNIV MINNESOTA,LIMNOL RES CTR,MINNEAPOLIS,MN 55455. US GEOL SURVEY,MENLO PK,CA 94025. GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP RIEHLE, JR (reprint author), US GEOL SURVEY,4200 UNIV DR,ANCHORAGE,AK 99508, USA. NR 18 TC 16 Z9 17 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 0033-5894 J9 QUATERNARY RES JI Quat. Res. PD MAR PY 1992 VL 37 IS 2 BP 183 EP 202 DI 10.1016/0033-5894(92)90081-S PG 20 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA HH406 UT WOS:A1992HH40600004 ER PT J AU HEYMSFIELD, GM FULTON, R AF HEYMSFIELD, GM FULTON, R TI MODULATION OF SSM/I MICROWAVE SOIL RADIANCES BY RAINFALL SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BRIGHTNESS TEMPERATURES; 183 GHZ; VEGETATION; MOISTURE; SATELLITE; PRECIPITATION; RADIOMETERS; EMISSION; SENSOR; MODEL AB This article presents a detailed case study of the observed impact of rainfall and soil moisture on microwave brightness temperatures of the lower Great Plains of the United States using SSM/I satellite data. The SSM/I channels provide better spatial resolution and are at higher frequencies than typically used for studies of this type. Examination of the SSM/I observations during a month and a half period in Oklahoma in 1987 indicated large spatial temperature variations due to both vegetation cover and soil moisture. The brightness temperatures of the land background were strongly modulated by rainfall during the study period. Areas of lowest brightness temperatures coincided with regions of bare soil which had received significant rainfall. Examination of the time history of brightness temperatures in the bare soil regions showed that rainfall events caused significant temperature drops, which persisted for at least several days. Time history plots of brightness temperature and the antecedent precipitation index during an extremely large rain event indicated a slow recovery period (approximately 15 days) back to the dry soil state. On the other hand, vegetated regions showed smaller temperature drops and much weaker correlation with rain events, thus questioning the feasibility of using these SSM/I measurements for soil moisture estimation. C1 SCI SYST & APPLICAT INC,LANHAM,MD. RP HEYMSFIELD, GM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. NR 28 TC 14 Z9 14 U1 1 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR PY 1992 VL 39 IS 3 BP 187 EP 202 DI 10.1016/0034-4257(92)90085-X PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA HJ882 UT WOS:A1992HJ88200003 ER PT J AU GANAPOL, BD MYNENI, RB AF GANAPOL, BD MYNENI, RB TI THE FN METHOD FOR THE ONE-ANGLE RADIATIVE-TRANSFER EQUATION APPLIED TO PLANT CANOPIES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID NEUTRON-TRANSPORT THEORY; SCATTERING; MODEL AB Solutions of the radiative transfer equation describing photon interactions with vegetation canopies are important in remote sensing since they provide the canopy reflectance distribution required in the interpretation of satellite-acquired information. Although the most widely used transport models such as the moments formulations collapse the photon directional information into a limited number of directions (usually two or four), the more sophisticated methods such as discrete ordinates can, in principle, employ an unlimited number of discrete directions. These discrete methods, however, also contain spatial discretization error and lack testing against more accurate numerical formulations for specific vegetation canopy scattering kernels. In this article, we consider a semianalytical approach to the solution of the one-angle radiative transfer equation in slab geometry called the F(N) method. This method has as its basis two integral equations specifying the intensities existing the vegetation canopy boundaries. The solution is then obtained through an expansion in a set of basis functions with expansion coefficients to be determined. These coefficients are obtained from a collocation procedure resulting in a set of algebraic equations solved by matrix inversion. The advantage of this method is that only discretization in the angular variable is required, thus avoiding spatial truncation error entirely. The paper begins by considering a canopy where all the leaves are oriented at the same angle. Lambertian scattering will be assumed with unequal leaf reflectance and transmittance. This simple model contains all the difficulties of the more complex model incorporating a general leaf angle distribution which is to be considered in the latter part of the presentation. A sensitivity analysis is performed including variation of the numerical and model parameters. In addition, discrete ordinates calculations as well as field measurements are compared to the F(N) results. C1 UNIV ARIZONA,DEPT NUCL ENGN,TUCSON,AZ 85721. RP GANAPOL, BD (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771, USA. RI Myneni, Ranga/F-5129-2012 NR 17 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR PY 1992 VL 39 IS 3 BP 213 EP 231 DI 10.1016/0034-4257(92)90087-Z PG 19 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA HJ882 UT WOS:A1992HJ88200005 ER PT J AU CHAPPELLE, EW KIM, MS MCMURTREY, JE AF CHAPPELLE, EW KIM, MS MCMURTREY, JE TI RATIO ANALYSIS OF REFLECTANCE SPECTRA (RARS) - AN ALGORITHM FOR THE REMOTE ESTIMATION OF THE CONCENTRATIONS OF CHLOROPHYLL-A, CHLOROPHYLL-B, AND CAROTENOIDS IN SOYBEAN LEAVES SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID PHOTOSYNTHETICALLY ACTIVE RADIATION; CORN CANOPIES; LEAF; WHEAT AB An algorithm utilizing reflectance spectra bands in the photosynthetically active radiation (PAR) region of the solar spectrum was developed for the remote estimation of the concentrations of chlorophyll a, chlorophyll b, and carotenoids in soybeans. The defining of specific bands in the reflectance spectrum that corresponded to absorption bands of the individual pigments was basic to the development of the algorithm. The detection of these bands was rendered difficult by the lack of detail in reflectance spectra. It was therefore necessary to manipulate the reflectance spectra so that absorption bands due to specific pigments could be detected and their spectral maxima defined. It was found that by dividing soybean reflectance spectra by an arbitrarily selected reference soybean reflectance spectrum, ratio spectra were obtained in which the absorption bands could be distinctly seen and their wavelength defined. These ratio spectra allowed the defining of those bands corresponding to the absorption bands of chlorophyll a, chlorophyll b, and carotenoids. The strong linear relationships of certain combinations of the bands in the ratio spectra to the concentrations of the photosynthetic pigments made it possible to develop a ratio analysis of reflectance spectra algorithm (RARS) by which the concentrations of these pigments could be calculated from the reflectance spectra. The measurements necessary for the development of RARS were made using soybeans which were grown at different nitrogen levels in order to obtain a range of reflectance spectra. A test of the RARS algorithm using other soybean plants showed very good agreement between measured pigment values and those calculated using RARS. C1 USDA ARS,BELTSVILLE AGR RES CTR,REMOTE SENSING RES LAB,BELTSVILLE,MD 20705. RP CHAPPELLE, EW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,CODE 923,GREENBELT,MD 20771, USA. NR 16 TC 360 Z9 412 U1 9 U2 70 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 MAR PY 1992 VL 39 IS 3 BP 239 EP 247 DI 10.1016/0034-4257(92)90089-3 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA HJ882 UT WOS:A1992HJ88200007 ER PT J AU DEVILLE, MO MUND, EH AF DEVILLE, MO MUND, EH TI FOURIER-ANALYSIS OF FINITE-ELEMENT PRECONDITIONED COLLOCATION SCHEMES SO SIAM JOURNAL ON SCIENTIFIC AND STATISTICAL COMPUTING LA English DT Article DE FINITE ELEMENT; COLLOCATION METHOD; EIGENVALUE ANALYSIS ID TSCHEBYSCHEFF PSEUDOSPECTRAL SOLUTION; EQUATIONS AB This paper investigates the spectrum of the iteration operator of some finite element preconditioned Fourier collocation schemes. The first part of the paper analyses one-dimensional elliptic and hyperbolic model problems and the advection-diffusion equation. Analytical expressions of the eigenvalues are obtained with use of symbolic computation. The second part of the paper considers the set of one-dimensional differential equations resulting from Fourier analysis (in the transverse direction) of the two-dimensional Stokes problem. All results agree with previous conclusions on the numerical efficiency of finite element preconditioning schemes. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. UNIV LIBRE BRUXELLES,SERV METROL NUCL,B-1050 BRUSSELS,BELGIUM. RP DEVILLE, MO (reprint author), CATHOLIC UNIV LOUVAIN,UNITE MECAN APPL,B-1348 LOUVAIN,BELGIUM. NR 10 TC 13 Z9 13 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0196-5204 J9 SIAM J SCI STAT COMP PD MAR PY 1992 VL 13 IS 2 BP 596 EP 610 DI 10.1137/0913033 PG 15 WC Mathematics, Applied SC Mathematics GA HE400 UT WOS:A1992HE40000010 ER PT J AU FORD, WF GROSJEAN, CC DEMEYER, H JORDAN, WB KING, AC OSBORNE, AD WILKINS, JE AF FORD, WF GROSJEAN, CC DEMEYER, H JORDAN, WB KING, AC OSBORNE, AD WILKINS, JE TI A 3RD-ORDER DIFFERENTIAL-EQUATION SO SIAM REVIEW LA English DT Letter C1 STATE UNIV GHENT,B-9000 GHENT,BELGIUM. NATL FUND SCI RES,BRUSSELS,BELGIUM. UNIV KEELE,KEELE ST5 5BG,STAFFS,ENGLAND. RP FORD, WF (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 1 TC 21 Z9 22 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 0036-1445 J9 SIAM REV JI SIAM Rev. PD MAR PY 1992 VL 34 IS 1 BP 121 EP 122 DI 10.1137/1034012 PG 2 WC Mathematics, Applied SC Mathematics GA HG150 UT WOS:A1992HG15000007 ER PT J AU BATES, JR FANG, PH AF BATES, JR FANG, PH TI RESULTS OF SOLAR-CELL PERFORMANCE ON LUNAR BASE DERIVED FROM APOLLO MISSIONS SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article AB Some characteristic variations of the solar cell performance on the lunar base, from Apollo lunar missions, are presented and analyzed. Two specific aspects, solar cell output variation during the lunar day and through several years are discussed. C1 BOSTON COLL,INST SPACE RES,NEWTON,MA 02159. RP BATES, JR (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 5 TC 5 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD MAR PY 1992 VL 26 IS 1-2 BP 79 EP 84 DI 10.1016/0927-0248(92)90127-B PG 6 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA HQ110 UT WOS:A1992HQ11000007 ER PT J AU RONAN, RS ORRALL, FQ MICKEY, DL WEST, EA HAGYARD, MJ BALASUBRAMANIAM, KS AF RONAN, RS ORRALL, FQ MICKEY, DL WEST, EA HAGYARD, MJ BALASUBRAMANIAM, KS TI A COMPARISON OF VECTOR MAGNETOGRAMS FROM THE MARSHALL-SPACE-FLIGHT-CENTER AND MEES-SOLAR-OBSERVATORY SO SOLAR PHYSICS LA English DT Article ID MAGNETIC-FIELDS AB We compare completely independent vector magnetic field measurements from two very different polarimetric instruments. The Marshall Space Flight Center's imaging vector magnetograph is based on a birefringent filter, routinely measuring all four Stokes parameters integrated over the filter bandpass (1/8 angstrom) which is tunable across the FeI lambda-5250 line in 10 m angstrom steps. The Haleakala Stokes Polarimeter of the Mees Solar Observatory (MSO) is based on a spectrometer, routinely measuring all four Stokes parameters of the FeI lambda-6302.5 line simultaneously and then spatially scanning to build up a vector magnetogram. We obtained active region magnetic field data with both the Marshall Space Flight Center (MSFC) and MSO systems on five days during June 1985. After interpolating the MSFC vector fields onto the more coarse spatial grid of MSO we make a point-by-point comparison of the two vector fields for data obtained on two of these days (June 8 and 9). From this comparison we conclude: (1) the spatially-averaged line-of-sight components agree quite well; (2) although the MSO spatial grid is coarser, the quality of the MSO image is better than that of the MSFC data because of better seeing conditions; (3) the agreement between the transverse magnitudes is affected by the poor image quality of the MSFC data; and (4) if the effects of Faraday rotation caused by including line-center linear polarization in the method of analysis are taken into account, the azimuths show good agreement within the scatter in the data caused by the averaging process. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP RONAN, RS (reprint author), UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822, USA. OI Balasubramaniam, Krishnan/0000-0003-2221-0933 NR 12 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 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAR PY 1992 VL 138 IS 1 BP 49 EP 68 DI 10.1007/BF00146196 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HH478 UT WOS:A1992HH47800006 ER PT J AU MAHONEY, JB MCNULTY, JK AF MAHONEY, JB MCNULTY, JK TI DISEASE-ASSOCIATED BLOOD CHANGES AND NORMAL SEASONAL HEMATOLOGICAL VARIATION IN WINTER FLOUNDER IN THE HUDSON-RARITAN ESTUARY SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Note ID STRESS; TROUT; FISH AB Hematological variables of diseased and apparently healthy winter flounder Pleuronectes americanus were evaluated during fin rot epizootics in the Hudson-Raritan estuary, New York-New Jersey. Most diseased fish had significantly lower (average, 43% lower; P < 0.05) levels of hemoglobin, erythrocytes, hematocrit, and plasma protein than healthy fish; blood deficiencies were more frequent among juveniles (ages 1 and 2) than adults. The results indicate that the disease had severe consequences for this species. Normal seasonal variation in winter flounder hematology was determined by assessment of healthy fish through an annual cycle. Hemoglobin, erythrocyte, and hematocrit values were high between October and April-May and low between June and September. Plasma protein levels were high in June-December (January data were not obtained), and low in February-May. Juveniles and adults differed significantly in levels of plasma protein through the annual cycle. Temporary (1-7-month) differences in hemoglobin and erythrocyte levels between juveniles and adults also were evident. RP NATL MARINE FISHERIES SERV, NE FISHERIES SCI CTR, SANDY HOOK LAB, HIGHLANDS, NJ 07732 USA. NR 34 TC 8 Z9 9 U1 1 U2 2 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0002-8487 EI 1548-8659 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAR PY 1992 VL 121 IS 2 BP 261 EP 268 DI 10.1577/1548-8659(1992)121<0261:NDBCAN>2.3.CO;2 PG 8 WC Fisheries SC Fisheries GA JH778 UT WOS:A1992JH77800011 ER PT J AU OWE, M VANDEGRIEND, AA CHANG, ATC AF OWE, M VANDEGRIEND, AA CHANG, ATC TI SURFACE MOISTURE AND SATELLITE MICROWAVE OBSERVATIONS IN SEMIARID SOUTHERN AFRICA SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL-MOISTURE; VEGETATION CANOPIES; RANGE DEGRADATION; EMPIRICAL-MODEL; WATER-CONTENT; EMISSION; ROUGHNESS; TEMPERATURE; IMAGERY; INDEX AB Nimbus 7 scanning multichannel microwave radiometer 6.6-GHz passive microwave data were studied in relation to large-scale soil moisture estimates over a 3-year period in southeastern Botswana. An extensive data base of weekly surface soil moisture measurements was used with meteorological data to estimate pixel average soil moisture on a daily basis. The influence of the vegetation canopy on the surface emissivity was studied by partitioning the data set into classes on the basis of the normalized difference vegetation index. After correcting for the vegetation optical depth, a correlation of r = 0.84 was established between the normalized brightness temperature observations and surface soil moisture for the 3-year period. C1 FREE UNIV AMSTERDAM,DEPT EARTH SCI,1007 MC AMSTERDAM,NETHERLANDS. RP OWE, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HYDROLOG SCI BRANCH,CODE 974,GREENBELT,MD 20771, USA. NR 36 TC 71 Z9 71 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1992 VL 28 IS 3 BP 829 EP 839 DI 10.1029/91WR02765 PG 11 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA HG175 UT WOS:A1992HG17500023 ER PT J AU BARROWS, LH STRICKLIN, MD WONG, WW KLEIN, PD INNERS, LD SICONOLFI, SF AF BARROWS, LH STRICKLIN, MD WONG, WW KLEIN, PD INNERS, LD SICONOLFI, SF TI COMPARISON OF TOTAL-BODY WATER ESTIMATES FROM O-18 AND BIOELECTRICAL RESPONSE PREDICTION EQUATIONS SO FASEB JOURNAL LA English DT Meeting Abstract C1 BAYLOR COLL MED,CHILDRENS NUTR RES CTR,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1769 EP A1769 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100981 ER PT J AU BREIT, GA WATENPAUGH, DE BALLARD, RE HARGENS, AR AF BREIT, GA WATENPAUGH, DE BALLARD, RE HARGENS, AR TI ACUTE CUTANEOUS FLOW AND VOLUME RESPONSES TO WHOLE-BODY TILTING IN HUMANS SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1771 EP A1771 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100993 ER PT J AU DEAN, M SLIVA, L JAWEED, M AF DEAN, M SLIVA, L JAWEED, M TI ACCENTUATED MUSCULAR COCONTRACTION AS AN INDICATOR OF ECCENTRIC EXERCISE-INDUCED MUSCLE DAMAGE SO FASEB JOURNAL LA English DT Meeting Abstract C1 METHODIST HOSP,BAYLOR COLL MED,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1832 EP A1832 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101346 ER PT J AU GREENISEN, M SMITH, RA KLUTE, G MCCAULLEY, JB SQUIRES, B AF GREENISEN, M SMITH, RA KLUTE, G MCCAULLEY, JB SQUIRES, B TI 2 TECHNIQUES FOR MEASURING LOCOMOTION IMPACT FORCES DURING O-G SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. MCDONNELL DOUGLAS SPACE SYST CO,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100987 ER PT J AU GREENLEAF, JE SHIRAKI, K SAGAWA, S NAKAMITSU, S MIKI, K WADA, F NAGAYA, K KEIL, LC HONG, SK AF GREENLEAF, JE SHIRAKI, K SAGAWA, S NAKAMITSU, S MIKI, K WADA, F NAGAYA, K KEIL, LC HONG, SK TI EFFECT OF WATER TEMPERATURE ON CARDIOVASCULAR-RESPONSES TO HEAD-OUT IMMERSION (HOI) SO FASEB JOURNAL LA English DT Meeting Abstract C1 UNIV OCCUPAT & ENVIRONM HLTH,KITAKYUSHU,FUKUOKA 807,JAPAN. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SUNY BUFFALO,BUFFALO,NY 14214. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1838 EP A1838 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101384 ER PT J AU HAYES, JC MCBRINE, JJ ROPER, ML STRICKLIN, MD SICONOLFI, SF GREENISEN, MC AF HAYES, JC MCBRINE, JJ ROPER, ML STRICKLIN, MD SICONOLFI, SF GREENISEN, MC TI EFFECTS OF SPACE-SHUTTLE FLIGHTS ON SKELETAL-MUSCLE PERFORMANCE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 10 Z9 10 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100988 ER PT J AU HONG, SK SAGAWA, S NAKAMITSU, S MIKI, K WADA, F NAGAYA, K KEIL, LC GREENLEAF, JE SHIRAKI, K AF HONG, SK SAGAWA, S NAKAMITSU, S MIKI, K WADA, F NAGAYA, K KEIL, LC GREENLEAF, JE SHIRAKI, K TI EFFECT OF WATER TEMPERATURE ON RENAL AND ENDOCRINE RESPONSES TO HEAD-OUT IMMERSION (HOI) SO FASEB JOURNAL LA English DT Meeting Abstract C1 UNIV OCCUPAT & ENVIRONM HLTH,KITAKYUSHU,FUKUOKA 807,JAPAN. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SUNY BUFFALO,BUFFALO,NY 14260. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1838 EP A1838 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101382 ER PT J AU KAWAI, Y MURTHY, G DEROSHIA, CW WATENPAUGH, DE BREIT, GA HARGENS, AR AF KAWAI, Y MURTHY, G DEROSHIA, CW WATENPAUGH, DE BREIT, GA HARGENS, AR TI HEAD-DOWN TILT INCREASES CEREBRAL BLOOD-FLOW VELOCITY IN HUMANS SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1771 EP A1771 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100991 ER PT J AU LATHERS, CM CHARLES, JB MUKAI, CN RIDDLE, JM JACOBS, FO BENNETT, BS LEWIS, D FORTNEY, S FREY, MB STRICKLIN, MD SCHNEIDER, VS AF LATHERS, CM CHARLES, JB MUKAI, CN RIDDLE, JM JACOBS, FO BENNETT, BS LEWIS, D FORTNEY, S FREY, MB STRICKLIN, MD SCHNEIDER, VS TI HEART-RATE RESPONSES TO LOWER-BODY NEGATIVE-PRESSURE (LBNP) DURING 17 WEEKS OF BEDREST SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,HOUSTON,TX 77058. US FDA,ROCKVILLE,MD 20857. LOCKHEED ENGINEER & SCI CO,WASHINGTON,DC. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1772 EP A1772 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101000 ER PT J AU MCBRINE, JJ HAYES, JC SICONOLFI, SF AF MCBRINE, JJ HAYES, JC SICONOLFI, SF TI EFFECTS OF IN-FLIGHT EXERCISE ON SKELETAL-MUSCLE PERFORMANCE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100986 ER PT J AU MOELLER, KA HOLLEY, DC DEROSHIA, CW MELE, G GOTT, J OKUMURA, S WINGET, CM CALLAHAN, PX AF MOELLER, KA HOLLEY, DC DEROSHIA, CW MELE, G GOTT, J OKUMURA, S WINGET, CM CALLAHAN, PX TI SOUND AND ITS EFFECTS ON CIRCADIAN FREE-RUNNING PERIODS OF SPRAGUE-DAWLEY RATS SO FASEB JOURNAL LA English DT Meeting Abstract C1 SAN JOSE STATE UNIV,DEPT BIOL SCI,SAN JOSE,CA 95192. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1831 EP A1831 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101343 ER PT J AU MOORE, AD FORTNEY, SM SICONOLFI, SF AF MOORE, AD FORTNEY, SM SICONOLFI, SF TI EFFECT OF AEROBIC CAPACITY ON LOWER-BODY NEGATIVE-PRESSURE (LBNP) TOLERANCE IN FEMALES SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,KRUG LIFE SCI & SPACE BIOMED RES INST,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1769 EP A1769 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100983 ER PT J AU MURTHY, G WATENPAUGH, DE BALLARD, RE WHALEN, RT HARGENS, AR AF MURTHY, G WATENPAUGH, DE BALLARD, RE WHALEN, RT HARGENS, AR TI FOOTWARD FORCES AND INTRAMUSCULAR PRESSURES GENERATED DURING EXERCISE IN SUPINE LOWER-BODY NEGATIVE-PRESSURE VERSUS UPRIGHT POSTURE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100984 ER PT J AU NAVIDI, M WOLINSKY, I ARNAUD, SB AF NAVIDI, M WOLINSKY, I ARNAUD, SB TI EFFECT OF DIETARY SALT ON BONE MASS IN A SPACE-FLIGHT MODEL SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. UNIV HOUSTON,HOUSTON,TX 77204. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1944 EP A1944 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101998 ER PT J AU PETERSON, TV KEIL, LC MORLEY, CD CARTER, AB MILLER, RA EVANS, J AF PETERSON, TV KEIL, LC MORLEY, CD CARTER, AB MILLER, RA EVANS, J TI RENAL NERVES AND VOLUME INDUCED CHANGES IN PLASMA-RENIN IN CONSCIOUS MONKEYS SO FASEB JOURNAL LA English DT Meeting Abstract C1 TEXAS A&M UNIV SYST,HLTH SCI CTR,DEPT MED PHYSIOL,COLLEGE STN,TX 77843. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1776 EP A1776 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101021 ER PT J AU SICONOLFI, SF BABB, TG REID, MB AF SICONOLFI, SF BABB, TG REID, MB TI VENTILATORY RESPONSES TO SUBMAXIMAL EXERCISE AFTER SPACE-FLIGHT SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. BAYLOR COLL MED,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1772 EP A1772 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100997 ER PT J AU SMITH, RA KLUTE, G MCCAULLEY, JB JONES, A GREENISEN, M AF SMITH, RA KLUTE, G MCCAULLEY, JB JONES, A GREENISEN, M TI A COMPARISON OF LOCOMOTION IMPACT FORCES - ONE-G VS ZERO-G SO FASEB JOURNAL LA English DT Meeting Abstract C1 MCDONNELL DOUGLAS SPACE SYST CO,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100985 ER PT J AU STOUT, MS WATENPAUGH, DE BREIT, GA HARGENS, AR AF STOUT, MS WATENPAUGH, DE BREIT, GA HARGENS, AR TI THE EFFECTS OF SIMULATED MICROGRAVITY ON REGIONAL CUTANEOUS MICROCIRCULATORY BLOOD-FLOW SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1771 EP A1771 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100994 ER PT J AU SUIRE, SS SICONOLFI, SF AF SUIRE, SS SICONOLFI, SF TI VALIDITY AND SENSITIVITY OF ESTIMATED VO2PEAK BEFORE AND AFTER EXPOSURE TO REAL OR SIMULATED MICROGRAVITY SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1770 EP A1770 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100989 ER PT J AU TISCHLER, AC HOLLEY, DC DEROSHIA, CW GOTT, J OKUMURA, S MELE, G WINGET, CM CALLAHAN, PX AF TISCHLER, AC HOLLEY, DC DEROSHIA, CW GOTT, J OKUMURA, S MELE, G WINGET, CM CALLAHAN, PX TI CIRCADIAN ENTRAINMENT OF MALE SPRAGUE - DAWLEY RATS USING LOW LIGHT-INTENSITY SO FASEB JOURNAL LA English DT Meeting Abstract C1 SAN JOSE STATE UNIV,DEPT BIOL SCI,SAN JOSE,CA 95192. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1832 EP A1832 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101344 ER PT J AU WADE, CE AF WADE, CE TI NEUROENDOCRINE RESPONSES TO HEMORRHAGE ARE POTENTIATED BY PRIOR DEHYDRATION SO FASEB JOURNAL LA English DT Meeting Abstract C1 LETTERMAN ARMY INST,SAN FRANCISCO,CA 94129. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1837 EP A1837 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27101374 ER PT J AU WATENPAUGH, DE BREIT, GA BALLARD, RE HARGENS, AR AF WATENPAUGH, DE BREIT, GA BALLARD, RE HARGENS, AR TI MONITORING ACUTE WHOLE-BODY FLUID REDISTRIBUTION BY CHANGES IN LEG AND NECK VOLUME SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 28 PY 1992 VL 6 IS 5 BP A1771 EP A1771 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HH271 UT WOS:A1992HH27100990 ER PT J AU POOLE, EL KNIGHT, NF DAVIS, DD AF POOLE, EL KNIGHT, NF DAVIS, DD TI HIGH-PERFORMANCE EQUATION SOLVERS AND THEIR IMPACT ON FINITE-ELEMENT ANALYSIS SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article RP POOLE, EL (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 244,HAMPTON,VA 23665, USA. NR 14 TC 11 Z9 11 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD FEB 28 PY 1992 VL 33 IS 4 BP 855 EP 868 DI 10.1002/nme.1620330412 PG 14 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA HC652 UT WOS:A1992HC65200011 ER PT J AU KOSTER, RD SUAREZ, MJ AF KOSTER, RD SUAREZ, MJ TI MODELING THE LAND SURFACE BOUNDARY IN CLIMATE MODELS AS A COMPOSITE OF INDEPENDENT VEGETATION STANDS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SIMPLE BIOSPHERE MODEL; GENERAL-CIRCULATION MODELS; SOIL-MOISTURE; PARAMETERIZATION; TRANSPIRATION; HYDROLOGY; LAYER; FIELD AB An efficient strategy for modeling the land surface boundary in general circulation models (GCMs) is presented which accounts for the effects of vegetation on surface energy fluxes and allows for an arbitrary number of vegetation types to coexist in a grid square. The GCM grid square is depicted as a "mosaic" of vegetation "tiles," with each tile consisting of a single vegetation type. The energy balance equation for each tile follows closely that of a single vegetation version of the simple biosphere (SiB) model of Sellers et al. (1986) but is simplified enough to be written in Penman-Monteith form. Each tile in the square is coupled independently to the GCM atmosphere, and tiles affect each other only through the atmosphere. This coupling strategy differs conceptually from that of models such as SiB that assume a homogeneous mixture of vegetation types within a GCM grid square. A quantitative comparison of the two strategies is presented. C1 NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, MODELING & SIMULAT BRANCH, GREENBELT, MD 20771 USA. RP KOSTER, RD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HYDROSPER PROC LAB, HYDROL SCI BRANCH, CODE 974, GREENBELT, MD 20771 USA. RI Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 27 TC 324 Z9 330 U1 3 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 28 PY 1992 VL 97 IS D3 BP 2697 EP 2715 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HG561 UT WOS:A1992HG56100004 ER PT J AU MILLER, JR RUSSELL, GL AF MILLER, JR RUSSELL, GL TI THE IMPACT OF GLOBAL WARMING ON RIVER RUNOFF SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CO2; CLIMATE; MODEL; SENSITIVITY; INCREASE AB River runoff from the world's major rivers is an important part of the hydrologic cycle. Runoff changes in response to global greenhouse-induced warming will have impacts in many areas, including agriculture, water resources, and land use. A global atmospheric model is used to calculate the annual river runoff for 33 of the world's major rivers for the present climate and for a doubled CO2 climate. The model has a horizontal resolution of 4-degrees x 5-degrees, but the runoff from each model grid box is quartered and added to the appropriate river drainage basin on a 2-degrees x 2.5-degrees resolution. The computed runoff depends on the model's precipitation, evapotranspiration, and soil moisture storage. For the doubled CO2 climate, the runoff increased for 25 to the 33 rivers, and in most cases the increases coincided with increased rainfall within the drainage basins. There were runoff increases in all rivers in high northern latitudes, with a maximum increase of 47%. At low latitudes there were both increases and decreases ranging from a 96% increase to a 43% decrease. The effect of the simplified model assumptions of land-atmosphere interactions on the results is discussed. C1 NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, WASHINGTON, DC 20546 USA. RP MILLER, JR (reprint author), RUTGERS STATE UNIV, COOK COLL, DEPT METEOROL & PHYS OCEANOG, NEW BRUNSWICK, NJ 08903 USA. NR 26 TC 131 Z9 133 U1 4 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 28 PY 1992 VL 97 IS D3 BP 2757 EP 2764 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HG561 UT WOS:A1992HG56100008 ER PT J AU ROSENZWEIG, C HILLEL, D AF ROSENZWEIG, C HILLEL, D TI THE EARTH AS TRANSFORMED BY HUMAN ACTION - GLOBAL AND REGIONAL CHANGES IN THE BIOSPHERE OVER THE PAST 300 YEARS - TURNER,BL, CLARK,WC, KATES,RW, RICHARDS,JF, MATHEWS,JT, MEYER,WB SO NATURE LA English DT Book Review C1 NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. UNIV MASSACHUSETTS,DEPT PLANT SOIL & ENVIRONM SCI,AMHERST,MA 01003. RP ROSENZWEIG, C (reprint author), COLUMBIA UNIV,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 27 PY 1992 VL 355 IS 6363 BP 781 EP 782 DI 10.1038/355781a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HF636 UT WOS:A1992HF63600041 ER PT J AU BROOKS, VL KEIL, LC AF BROOKS, VL KEIL, LC TI REGULATION OF BLOOD-PRESSURE AND VASOPRESSIN DURING HEMORRHAGE IN CONSCIOUS, PREGNANT DOGS SO FASEB JOURNAL LA English DT Meeting Abstract C1 OREGON HLTH SCI UNIV,PORTLAND,OR 97201. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1461 EP A1461 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71903036 ER PT J AU DEARBORN, AS ERTL, AC BARNES, PR GREENLEAF, JE AF DEARBORN, AS ERTL, AC BARNES, PR GREENLEAF, JE TI EFFECTS OF ORAL GLUCOSE ON EXERCISE THERMOREGULATION AFTER WATER IMMERSION IN MEN SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. SAN FRANCISCO STATE UNIV,SAN FRANCISCO,CA 94132. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1198 EP A1198 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71901509 ER PT J AU FROST, SJ WHITSON, PA AF FROST, SJ WHITSON, PA TI CHARACTERIZATION OF AN ENDOTHELIAL-CELL SURFACE PEPTIDASE THAT DEGRADES ATRIAL-NATRIURETIC-PEPTIDE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1491 EP A1491 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71903211 ER PT J AU GALAVIZMORENO, S ESPINOZALOPEZ, A MAIORINO, PM REID, BL AF GALAVIZMORENO, S ESPINOZALOPEZ, A MAIORINO, PM REID, BL TI AGE AND DIET EFFECTS ON ENERGY-UTILIZATION OF MALE-RATS MEASURED BY INDIRECT CALORIMETRY SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,NUTR SCI PROGRAM,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1117 EP A1117 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71901050 ER PT J AU GRETEBECK, R DAVISSTREET, J SCHOELLER, D LANE, H AF GRETEBECK, R DAVISSTREET, J SCHOELLER, D LANE, H TI ENERGY REGULATION DURING 10 DAYS OF SIMULATED MICROGRAVITY SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,LYNDON B JOHNSON SPACE CTR,NUTR BIOCHEM LAB,HOUSTON,TX 77058. NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1117 EP A1117 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71901049 ER PT J AU KAHAN, NJ ARATOW, M WATENPAUGH, DE BALLARD, RE STYT, J CRENSHAW, A HARGENS, AR AF KAHAN, NJ ARATOW, M WATENPAUGH, DE BALLARD, RE STYT, J CRENSHAW, A HARGENS, AR TI SURFACE EMG VERSUS INTRAMUSCULAR EMG - CORRELATIONS WITH JOINT TORQUE DURING ISOMETRIC, CONCENTRIC, AND ECCENTRIC EXERCISE SO FASEB JOURNAL LA English DT Meeting Abstract C1 NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. NR 0 TC 2 Z9 2 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1237 EP A1237 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71901735 ER PT J AU THRASHER, TN KEIL, LC AF THRASHER, TN KEIL, LC TI RELATIONSHIPS AMONG PLASMA OSMOLALITY, PLASMA VASOPRESSIN AND WATER-INTAKE IN RESPONSE TO EATING IN DOGS SO FASEB JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 0 TC 0 Z9 0 U1 1 U2 1 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1461 EP A1461 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71903039 ER PT J AU WEST, TG ARTHUR, PG BRILL, RW SCHULTE, PM HOCHACHKA, PW AF WEST, TG ARTHUR, PG BRILL, RW SCHULTE, PM HOCHACHKA, PW TI RAPID AND SYNCHRONOUS CHANGES IN LACTATE AND PCR IN VERTEBRATE WHITE MUSCLE DURING RECOVERY FROM EXERCISE SO FASEB JOURNAL LA English DT Meeting Abstract C1 UNIV BRITISH COLUMBIA,VANCOUVER V6T 1W5,BC,CANADA. NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU,HI. NR 0 TC 0 Z9 0 U1 0 U2 1 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB 26 PY 1992 VL 6 IS 4 BP A1197 EP A1197 PN 1 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA HG719 UT WOS:A1992HG71901505 ER PT J AU LEU, MT BLAMONT, JE ANBAR, AD KEYSER, LF SANDER, SP AF LEU, MT BLAMONT, JE ANBAR, AD KEYSER, LF SANDER, SP TI ADSORPTION OF CO ON OXIDE AND WATER ICE SURFACES - IMPLICATIONS FOR THE MARTIAN ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HETEROGENEOUS REACTIONS; MARS; STABILITY; ANATASE; PHOTOCHEMISTRY AB The adsorption of carbon monoxide (CO) on water ice and on the oxides Fe2O3, Fe3O4, Al2O3, SiO2, CaO, MgO, and TiO2 (rutile and anatase) has been investigated in a flow reactor. A mass spectrometer was employed as a detector to monitor the temporal concentrations of CO. We have measured adsorption coefficients as large as 1 X 10(-4) for CO on TiO2 solids in helium at 196 K. The fractional surface coverage for CO on TiO2 solids in helium was also determined to be approximately 10% at 1% K. The upper limits of the fractional surface coverage for the other oxides (Fe2O3, Fe3O4, Al2O3, SiO2, CaO, and MgO) and water ice were also measured to be less than 1%. The implications for the stability of CO2 in the Martian atmosphere and the ''CO hole'' observed by the Phobos/ISM (infrared spectrometer) experiment are discussed. C1 JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109. NR 35 TC 9 Z9 9 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 25 PY 1992 VL 97 IS E2 BP 2621 EP 2627 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA KU046 UT WOS:A1992KU04600002 ER PT J AU RUBINCAM, DP AF RUBINCAM, DP TI MARS SECULAR OBLIQUITY CHANGE DUE TO THE SEASONAL POLAR CAPS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ASTRONOMICAL THEORY; CARBON-DIOXIDE; CLIMATE; REGOLITH; INERTIA; CYCLE; CO2; OSCILLATIONS; ATMOSPHERE; INSOLATION AB There is a weak positive feedback mechanism between the astronomy and meteorology of Mars. The mechanism is this: the seasonal waxing and waning polar caps cause small changes in Mars' dynamical flattening. Because the changes in flattening are out of phase with the Sun, there is a net annual solar torque on the planet which increases the angle between the equatorial and orbital planes. On the basis of Viking observations of the present climate and simple atmospheric models of past climates these seasonal shifts of mass between the atmosphere and polar caps are capable of secularly increasing Mars' obliquity by about 1-degrees or 2-degrees since the origin of the solar system. Thus the climate, driven largely by the axial tilt, reacts back on the planet and slightly enhances the seasons on Mars as time progresses. More sophisticated models will probably not change this result much; therefore this mechanism probably produced only minor changes in Mars' climate. It causes negligible changes in the axial tilt and climate of the Earth. C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GEODYNAM BRANCH,GREENBELT,MD 20771. RI Rubincam, David/D-2918-2012 NR 27 TC 4 Z9 4 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 25 PY 1992 VL 97 IS E2 BP 2629 EP 2632 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA KU046 UT WOS:A1992KU04600003 ER PT J AU FATHAUER, RW GEORGE, T KSENDZOV, A VASQUEZ, RP AF FATHAUER, RW GEORGE, T KSENDZOV, A VASQUEZ, RP TI VISIBLE LUMINESCENCE FROM SILICON-WAFERS SUBJECTED TO STAIN ETCHES SO APPLIED PHYSICS LETTERS LA English DT Article ID POROUS SILICON AB Etching of Si in a variety of solutions is known to cause staining. These stain layers consist of porous material similar to that produced by anodic etching of Si in HF solutions. We have observed photoluminescence peaked in the red from stain-etched Si wafers of different dopant types, concentrations, and orientations produced in solutions of HF:HNO3:H2O. Luminescence is also observed in stain films produced in solutions of NaNO2 in HF, but not in stain films produced in solutions of CrO3 in HF. The luminescence spectra are similar to those reported recently for porous Si films produced by anodic etching in HF solutions. However, stain films are much easier to produce, requiring no special equipment. RP FATHAUER, RW (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 7 TC 208 Z9 211 U1 2 U2 18 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 24 PY 1992 VL 60 IS 8 BP 995 EP 997 DI 10.1063/1.106485 PG 3 WC Physics, Applied SC Physics GA HE661 UT WOS:A1992HE66100026 ER PT J AU VASQUEZ, RP FATHAUER, RW GEORGE, T KSENDZOV, A LIN, TL AF VASQUEZ, RP FATHAUER, RW GEORGE, T KSENDZOV, A LIN, TL TI ELECTRONIC-STRUCTURE OF LIGHT-EMITTING POROUS SI SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON FILMS; AMORPHOUS-SILICON; DIFFRACTION; CRYSTALLINE; SURFACE; STATES AB Characterization of light-emitting porous Si films with x-ray photoelectron spectroscopy is reported. Only traces of O are detected on HF-etched samples, in contradiction to an earlier report that oxides are a significant component of porous Si. Si 2p and valence-band measurements demonstrate that the near-surface region of high porosity films which exhibit visible luminescence consists of amorphous Si. RP VASQUEZ, RP (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 20 TC 198 Z9 200 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 24 PY 1992 VL 60 IS 8 BP 1004 EP 1006 DI 10.1063/1.106503 PG 3 WC Physics, Applied SC Physics GA HE661 UT WOS:A1992HE66100029 ER PT J AU LEE, KY NAIR, VP WEINBERG, EJ AF LEE, KY NAIR, VP WEINBERG, EJ TI A CLASSICAL INSTABILITY OF REISSNER-NORDSTROM SOLUTIONS AND THE FATE OF MAGNETICALLY CHARGED BLACK-HOLES SO PHYSICAL REVIEW LETTERS LA English DT Article ID MONOPOLES; FIELD AB Working in the context of spontaneously broken gauge theories, we show that the magnetically charged Reissner-Nordstrom solution develops a classical instability if the horizon is sufficiently small. This instability has significant implications for the evolution of a magnetically charged black hole. In particular, it leads to the possibility that such a hole could evaporate completely, leaving in its place a nonsingular magnetic monopole. C1 FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP LEE, KY (reprint author), COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027, USA. RI Lee, Kimyeong/K-1070-2013 OI Lee, Kimyeong/0000-0003-3451-1514 NR 15 TC 90 Z9 90 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 24 PY 1992 VL 68 IS 8 BP 1100 EP 1103 DI 10.1103/PhysRevLett.68.1100 PG 4 WC Physics, Multidisciplinary SC Physics GA HE603 UT WOS:A1992HE60300003 ER PT J AU BAUSCHLICHER, CW AF BAUSCHLICHER, CW TI THE PHOTOELECTRON-SPECTROSCOPY OF NICL2 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GAUSSIAN-BASIS SETS; ELECTRONIC-STRUCTURE CALCULATIONS; TRANSITION-METAL DICHLORIDES; MOLECULAR CALCULATIONS; ROW ATOMS; DIHALIDES; ORBITALS AB Cl 3p and Ni 3d ionization energies are computed at the complete-active-space self-consistent-field level. The calculations yield 224 ion states within 25 eV of the neutral ground state. Of these, only about 11 are predicted to contribute sizably to the photoelectron spectra. The calculations show that the low-lying states of the ion correspond to ligand holes, not 3d holes as previously assigned. This conclusion is discussed in relation to the intensity differences between the He(I) and He(II) spectra. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 15 TC 1 Z9 1 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 21 PY 1992 VL 189 IS 6 BP 549 EP 553 DI 10.1016/0009-2614(92)85248-9 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HF181 UT WOS:A1992HF18100011 ER PT J AU ANDERSON, SM MORTON, J MAUERSBERGER, K YUNG, YL DEMORE, WB AF ANDERSON, SM MORTON, J MAUERSBERGER, K YUNG, YL DEMORE, WB TI A STUDY OF ATOM EXCHANGE BETWEEN O2(1-DELTA) AND OZONE SO CHEMICAL PHYSICS LETTERS LA English DT Article ID RECOMBINATION; STRATOSPHERE; OXYGEN AB It has recently been suggested that isotope exchange between excited bimolecular oxygen and ozone may be partially responsible for the enrichments in stratospheric heavy ozone. To begin evaluating this possibility we have investigated the reaction O-18(2)(1-DELTA) + O-16(3) --> (labeled ozone products) using a fast-flow reactor and molecular beam mass spectrometry. No reaction was observed, implying that the rate coefficient must be less than 5 x 10(-16) cm3/s molecule at 300 K, roughly two orders of magnitude smaller than is required to account for the atmospheric anomalies. C1 UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP ANDERSON, SM (reprint author), UNIV MINNESOTA,AUGSBURG COLL,DEPT PHYS,MINNEAPOLIS,MN 55455, USA. NR 22 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 21 PY 1992 VL 189 IS 6 BP 581 EP 585 DI 10.1016/0009-2614(92)85254-8 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HF181 UT WOS:A1992HF18100017 ER PT J AU CONSIDINE, DB DOUGLASS, AR STOLARSKI, RS AF CONSIDINE, DB DOUGLASS, AR STOLARSKI, RS TI HETEROGENEOUS CONVERSION OF N2O5 TO HNO3 ON BACKGROUND STRATOSPHERIC AEROSOLS - COMPARISONS OF MODEL RESULTS WITH DATA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIMB INFRARED MONITOR; ODD NITROGEN; NITRIC-ACID; CHEMISTRY; NIMBUS-7; OZONE; WINTER; NO2; O-3 AB A two dimensional photochemical model is used to examine the effects of heterogeneous processing by a parameterized lower stratospheric sulfate aerosol layer on model calculations. The single reaction considered is N2O5 + H2O --> 2HNO3, at a rate consistent with recent laboratory measurements. The calculations are compared with data, to see if the heterogeneous chemistry improves the agreement between model calculations and data. The data used are Limb Infrared Monitor of the Stratosphere (LIMS) measurements of HNO3 and NO2, and in situ measurements of NO, NO(y), and ClO taken by the NASA ER-2 aircraft. A contradictory picture results. With heterogeneous processing, model HNO3 agrees better with LIMS HNO3; however, LIMS NO2, and NO2/HNO3 agree more closely with the results of a standard gas-phase calculation. High-latitude NO/NO(y) from in situ measurements in winter also favor standard chemistry, while the seasonal variation of NO and NO2 are better represented when the heterogeneous reaction is included. ClO is also better simulated when the heterogeneous reaction is included. These comparisons suggest that the assumptions made to parameterize the sulfate aerosol chemistry result in a rate of heterogeneous processing that is too vigorous. However, the lack of consistency in the different comparisons leaves the situation ambiguous, and a definite conclusion is unwarranted. RP CONSIDINE, DB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 916,GREENBELT,MD 20771, USA. RI Douglass, Anne/D-4655-2012; Stolarski, Richard/B-8499-2013 OI Stolarski, Richard/0000-0001-8722-4012 NR 26 TC 29 Z9 29 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 21 PY 1992 VL 19 IS 4 BP 397 EP 400 DI 10.1029/92GL00125 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HF221 UT WOS:A1992HF22100017 ER PT J AU ARNOLDY, RL LYNCH, KA KINTNER, PM VAGO, J CHESNEY, S MOORE, TE POLLOCK, CJ AF ARNOLDY, RL LYNCH, KA KINTNER, PM VAGO, J CHESNEY, S MOORE, TE POLLOCK, CJ TI BURSTS OF TRANSVERSE ION-ACCELERATION AT ROCKET ALTITUDES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WAVES; IONOSPHERE; PLASMA AB High time resolution ion mass spectrometer distribution function measurements and wave data from a sounding rocket flight over an aurora have revealed the fine structure of the transverse ion acceleration mechanism in the upper ionosphere. The transversely accelerated ion (TAI) events can occur in a volume with a cross-field dimension as small as several tens of meters and thus appear as 50-100 ms ion bursts due to the rocket payload motion. Bulk heating to a characteristic energy of several eV and tail heating in the direction perpendicular to B of a few percent of ambient ions to a characteristic energy the order of 10 eV occur for both hydrogen and oxygen ions. The TAI at 90-degrees pitch angle occur in localized regions of intense lower hybrid waves and in regions of density depletion. On close examination of the correlation between the wave bursts and the TAI it is believed that the waves produce the ion acceleration. The TAI occur during periods of field-aligned auroral electron bursts. Finally, near 1000 km altitude they occur about once every second. If the event presented here is considered average, the flux of TAI oxygen ions above 7 eV could account for the ion conic fluxes measured by the ISIS spacecraft. C1 CORNELL UNIV,DEPT ELECT ENGN,ITHACA,NY 14853. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP ARNOLDY, RL (reprint author), UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,DURHAM,NH 03824, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 14 TC 64 Z9 64 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 21 PY 1992 VL 19 IS 4 BP 413 EP 416 DI 10.1029/92GL00091 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HF221 UT WOS:A1992HF22100021 ER PT J AU MORRISON, D AF MORRISON, D TI JUST AWARDS SO SCIENCE LA English DT Letter RP MORRISON, D (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 21 PY 1992 VL 255 IS 5047 BP 903 EP 903 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HE605 UT WOS:A1992HE60500002 ER PT J AU ADLERGOLDEN, SM GOLDSTEIN, N BIEN, F MATTHEW, MW GERSH, ME CHENG, WK ADAMS, FW AF ADLERGOLDEN, SM GOLDSTEIN, N BIEN, F MATTHEW, MW GERSH, ME CHENG, WK ADAMS, FW TI LASER RAMAN SENSOR FOR MEASUREMENT OF TRACE-HYDROGEN GAS SO APPLIED OPTICS LA English DT Article DE LASER; RAMAN; HYDROGEN; DETECTION; MEASUREMENT; HERRIOTT CAVITY AB A new optical hydrogen sensor based on spontaneous Raman scattering of laser light has been designed and constructed for rugged field use. It provides good sensitivity (better than 100 parts in 10(6)), rapid response (several seconds), and the inherent Raman characteristics of linearity and background gas independence of the signal. Efficient light collection and discrimination by using fast optics and a bandpass interference filter compensate for the inefficiency of the Raman-scattering process. A multipass optical cavity with a Herriott-type configuration provides intense illumination from an air-cooled cw gas laser. The observed performance is in good agreement with the theoretical signal and noise level predictions. C1 NASA,KENNEDY SPACE CTR,FL 32899. MIT,DEPT MECH ENGN,CAMBRIDGE,MA 02139. RP ADLERGOLDEN, SM (reprint author), SPECTRAL SCI INC,BURLINGTON,MA 01803, USA. NR 6 TC 25 Z9 25 U1 1 U2 9 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 20 PY 1992 VL 31 IS 6 BP 831 EP 835 PG 5 WC Optics SC Optics GA HD626 UT WOS:A1992HD62600024 PM 20720690 ER PT J AU VERTER, F AF VERTER, F TI PREDICTED GALAXY COUNTS IN CO EMISSION SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY, THEORY; GALAXIES, ISM; GALAXIES, LUMINOSITY FUNCTION, MASS FUNCTION; SURVEYS ID FAR-INFRARED LUMINOSITY; LARGE-SCALE STRUCTURE; STAR-FORMATION RATES; VIRGO CLUSTER; IRAS OBSERVATIONS; REDSHIFT SURVEY; MOLECULAR GAS; SYSTEMATIC PROPERTIES; INTERACTING GALAXIES; SPIRAL GALAXIES AB The average number of galaxies per square degree with CO (1-0) emission above a brightness threshold of 4.5 x 10(-20) W m-2 is predicted to be 0.5 +/- 4.0. This prediction is derived by integrating over the CO luminosity function of galaxies, where the shape of the luminosity function is determined from the FCRAO Extragalactic CO Survey of nearby infrared-selected galaxies, and the amplitude is determined from the Center for Astrophysies redshift survey in combination with the L(CO)-L(B) correlation of the shape sample. The expressed uncertainty in the predicted galaxy counts comes primarily from uncertainties in the absolute scale and high-luminosity cutoff of the CO luminosity function. Using present technology mm-radio telescopes and receivers, it is possible to use galaxy counts in CO (l-0) emission to test theories of recent (z less-than-or-equal-to 0.4) galaxy evolution. If it is true that interactions among galaxies and consequent starbursts were more common in the recent past, as suggested by galaxy counts at far-infrared and cm-radio wavelengths, then it is anticipated that the molecular emission of galaxies will increase with redshift and the CO galaxy counts will exceed this prediction based on nearby galaxies. RP VERTER, F (reprint author), NASA,GODDARD SPACE FLIGHT CTR,M-C 685,GREENBELT,MD 20771, USA. NR 64 TC 1 Z9 1 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 20 PY 1992 VL 386 IS 2 BP 398 EP 407 DI 10.1086/171026 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC827 UT WOS:A1992HC82700002 ER PT J AU MALUMUTH, EM AF MALUMUTH, EM TI THE DISTRIBUTION OF CD GALAXY PECULIAR VELOCITIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, CLUSTERING; GALAXIES, INTERACTIONS ID BRIGHTEST CLUSTER MEMBERS; RICH CLUSTERS; POOR CLUSTERS; LUMINOSITY FUNCTION; EVOLUTION; DYNAMICS; RELAXATION; CANNIBALISM; DISPERSIONS; ENCOUNTERS AB Recent observations that cD galaxies sometimes have large (300-400 km s-1) peculiar have cast the idea that cD galaxies are formed by mergers in a virialized cluster into doubt. In order to test whether cD galaxies with large peculiar velocities could be formed in such clusters, a cluster evolution computer code which takes into account the processes of two-body relaxation, dynamical friction, galaxy-galaxy stripping collisions, and mergers has been modified to follow galaxy orbits in an N-body fashion. A total of 258 simulations of richness class - 1 to 0 clusters (N(gal) = 100) were run, 50 of which, or 19%, formed cD galaxies. Thus for similar initial conditions the frequency of cD galaxy formation is much lower than in the earlier version of the code. At the time of their formation the cD galaxies have a distribution of peculiar velocities similar to that of observed cD galaxies. However, by the end of the simulations (10(10) yr for H0 = 50) the cD galaxies have been dragged to the center of the cluster by dynamical friction and the distribution of peculiar velocities is inconsistent with the observed distribution. The typical cD galaxy has nine mergers and is 5 L*. This is in comparison with the observed luminosity of Morgan poor clusters of 7 L*. RP MALUMUTH, EM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GHRS SCI TEAM,COMP SCI CORP,ASTRON PROGRAMS,CODE 681,GREENBELT,MD 20771, USA. NR 50 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 FEB 20 PY 1992 VL 386 IS 2 BP 420 EP 431 DI 10.1086/171028 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC827 UT WOS:A1992HC82700004 ER PT J AU XIE, XF MUMMA, MJ AF XIE, XF MUMMA, MJ TI THE EFFECT OF ELECTRON COLLISIONS ON ROTATIONAL POPULATIONS OF COMETARY WATER SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; COMETS, INDIVIDUAL (HALLEY); MOLECULAR PROCESSES ID HALLEYS-COMET; INNER COMA; EXCITATION; P/HALLEY; H2O; EXPANSION; MOLECULE; VAPOR; MODEL AB The e-H2O collisional rate for exciting rotational transitions in cometary water is evaluated for conditions found in comet Halley during the Giotto spacecraft encounter. In the case of the 0(00) --> i(ii) rotational transition, the e-H2O collisional rate exceeds that for excitation by neutral-neutral collisions at distances exceeding 3000 km from the cometary nucleus. The estimates are based on theoretical and experimental studies of e-H2O collisions, on ion and electron parameters acquired in situ by instruments on the Giotto and Vega spacecraft, and on results obtained from models of the cometary ionosphere. Thus, the rotational temperature of the water molecule in the intermediate coma may be controlled by collisions with electrons rather than with neutral molecules, and the rotational temperature retrieved from high-resolution infrared spectra of water in comet Halley may reflect electron temperatures rather than neutral gas temperatures in the intermediate coma. The contribution of electron collisions may explain the need for large H2O-H2O cross sections in models which neglect the effect of electrons. The importance of electron collisions is enhanced for populations of water molecules in regions where their rotational lines are optically thick. C1 UNIV PENN,DEPT ASTRON,PHILADELPHIA,PA 19104. RP XIE, XF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 693,GREENBELT,MD 20771, USA. RI mumma, michael/I-2764-2013 NR 33 TC 53 Z9 53 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1992 VL 386 IS 2 BP 720 EP 728 DI 10.1086/171053 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC827 UT WOS:A1992HC82700029 ER PT J AU PARRISH, A CONNOR, BJ TSOU, JJ MCDERMID, IS CHU, WP AF PARRISH, A CONNOR, BJ TSOU, JJ MCDERMID, IS CHU, WP TI GROUND-BASED MICROWAVE MONITORING OF STRATOSPHERIC OZONE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB A microwave instrument developed for operational measurements of ozone for the Network for Detection of Stratospheric Change is discussed. The instrument observes two spectral lines near 3 mm wavelength with a bandwidth of 630 MHz, allowing profile retrieval from 20 to 70 km. The observing technique and calibration procedures are described. The measurement forward model and retrieval algorithm are formulated. Preliminary comparisons with a co-located ground-based lidar and the SAGE II instrument are presented. The measurements are shown to typically agree to within 5 to 10%. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV MASSACHUSETTS, TABLE MT FACIL, AMHERST, MA 01003 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA USA. RP PARRISH, A (reprint author), MILLITECH CORP, POB 109, S DEERFIELD, MA 01373 USA. NR 14 TC 69 Z9 71 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1992 VL 97 IS D2 BP 2541 EP 2546 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HE957 UT WOS:A1992HE95700010 ER PT J AU GOLDMAN, A MURCRAY, FJ BLATHERWICK, RD KOSTERS, JJ MURCRAY, DG RINSLAND, CP FLAUD, JM CAMYPEYRET, C AF GOLDMAN, A MURCRAY, FJ BLATHERWICK, RD KOSTERS, JJ MURCRAY, DG RINSLAND, CP FLAUD, JM CAMYPEYRET, C TI STRATOSPHERIC HNO3 MEASUREMENTS FROM 0.002-CM-1 RESOLUTION SOLAR OCCULTATION SPECTRA AND IMPROVED SPECTROSCOPIC LINE PARAMETERS IN THE 5.8-MU-M REGION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HETERODYNE FREQUENCY MEASUREMENTS; WAVELENGTH CALIBRATION TABLES; BALLOON-BORNE; NITRIC-ACID; LABORATORY SPECTRA; TEMPERATURE-DEPENDENCE; ABSORPTION-SPECTRA; 11.6-MU-M BAND; LEAST-SQUARES; TRACE GASES AB Measurements of stratospheric HNO3 are presented based on new very high resolution (0.002-cm-1 full width at half maximum (FWHM)) solar occultation spectra recorded at 32-degrees-N latitude with a balloon-borne interferometer in the region of the HNO3 nu-2 band at 5.8-mu-m and improved spectroscopic line parameters generated for this HNO3 band and the interfering bands of O3 and H2O. The line parameters for HNO3, computed from the spectroscopic constants reported by Maki, are a significant improvement in that the calculated positions are more accurate than previous data and the line list now includes higher J and K(a) transitions needed to account for weaker HNO3 absorption features observable in the stratospheric spectra. Verifications of the new line parameters based on the stratospheric spectra and a 0.002-cm-1 resolution HNO3 laboratory spectrum are presented along with comparisons generated with the parameters from the 1986 HITRAN compilation. Significant improvements are apparent for all the updated bands. Finally, the stratospheric HNO3 profile retrieved from the stratospheric solar spectra using a nonlinear least squares fitting algorithm and the new line parameters is reported and compared with previously reported measurements. C1 UNIV PARIS 06, CNRS, PHYS MOLEC & APPLICAT LAB, F-75252 PARIS 05, FRANCE. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. RP GOLDMAN, A (reprint author), UNIV DENVER, DEPT PHYS, 2112 E WESLEY, DENVER, CO 80208 USA. NR 43 TC 11 Z9 11 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1992 VL 97 IS D2 BP 2561 EP 2567 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HE957 UT WOS:A1992HE95700012 ER PT J AU LEVINE, DM WILLETT, JC AF LEVINE, DM WILLETT, JC TI COMMENT ON THE TRANSMISSION-LINE MODEL FOR COMPUTING RADIATION FROM LIGHTNING SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RETURN-STROKE; ELECTROMAGNETIC-RADIATION; MAGNETIC-FIELDS AB The "transmission-line" model is an approximation that is frequently used to relate the electric and magnetic fields radiated during lighning discharges to the currents that produce those fields. A principal prediction of this model is that the distant (radiation) fields are directly proportional to the current propagating along the lightning channel, multiplied by the velocity of propagation. This paper examines the derivation of this relationship and its implications in some detail. We show that the formulas commonly used to describe the transmission-line model cannot be correctly applied to many lightning processes. A correction factor is required that is significant when the channel is not oriented perpendicular to the line of sight to the observer, unless the propagation velocity is only a small fraction of the speed of light. An important implication of this more general version of the model is that the current and velocity decouple so that they could be separately determined by suitable, multistation measurements. C1 PHILLIPS LAB, GEOPHYS DIRECTORATE, BEDFORD, MA 01731 USA. RP LEVINE, DM (reprint author), NASA, GODDARD SPACE FLIGHT CTR, MICROWAVE SENSORS BRANCH, MAIL CODE 675, GREENBELT, MD 20771 USA. NR 24 TC 25 Z9 25 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 FEB 20 PY 1992 VL 97 IS D2 BP 2601 EP 2610 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA HE957 UT WOS:A1992HE95700016 ER PT J AU KLEMM, RB SUTHERLAND, JW RABINOWITZ, MJ PATTERSON, PM QUARTEMONT, JM WEN, T AF KLEMM, RB SUTHERLAND, JW RABINOWITZ, MJ PATTERSON, PM QUARTEMONT, JM WEN, T TI SHOCK-TUBE KINETIC-STUDY OF METHANE DISSOCIATION - 1726-K LESS-THAN-OR-EQUAL-TO-T-LESS-THAN-OR-EQUAL-TO 2134-K SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID RESONANCE-ABSORPTION; FLASH-PHOTOLYSIS; RATE CONSTANTS; + H; TEMPERATURE; DECOMPOSITION; PYROLYSIS; WAVES; OXIDATION; PRESSURE AB In this kinetic study of the thermal dissociation of methane in argon, primary product H atoms were monitored directly using the sensitive ARAS detection method. Absolute H atom concentration was determined in separate calibration experiments using N2O/H2 mixtures diluted in argon. Rate constants were obtained under or near low-pressure limit conditions in shock tube experiments performed in the reflected regime. The CH4 mole fraction was varied between 100 and 1300 ppm, and conversions of CH4 were typically 0.2% or less. The temperature ranged from 1726 to 2134 K. Rate data were analyzed at T less-than-or-equal-to 1900 K using a steady-state approximation, and at higher temperatures, rate constants were derived from simulations of [H](t) profiles. The results of 37 experimental determinations were fit to the following Arrhenius expression: k-degrees-diss(T) = 6.8 x 10(-8) exp(-44900K/T) cm3 molecule-1 S-1. The overall uncertainty of values derived from this expression is estimated to be about +/- 50%. RRKM and master equation calculations were performed to evaluate the fall-off behavior of the unimolecular rate constant and to allow comparison of the present results with those of previous studies of methane dissociation. A large discrepancy is noted, and some reasons for this disagreement are discussed. C1 NASA,LERC,CLEVELAND,OH 44135. RP KLEMM, RB (reprint author), BROOKHAVEN NATL LAB,BLDG 815,UPTON,NY 11973, USA. NR 39 TC 17 Z9 17 U1 0 U2 3 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 FEB 20 PY 1992 VL 96 IS 4 BP 1786 EP 1793 DI 10.1021/j100183a054 PG 8 WC Chemistry, Physical SC Chemistry GA HF283 UT WOS:A1992HF28300054 ER PT J AU GAYDOSH, DJ DRAPER, SL NOEBE, RD NATHAL, MV AF GAYDOSH, DJ DRAPER, SL NOEBE, RD NATHAL, MV TI ROOM-TEMPERATURE FLOW AND FRACTURE OF FE-40AT-PERCENT-AL ALLOYS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID FEAL SINGLE-CRYSTALS; YIELD STRENGTH; GRAIN-SIZE; AL-ALLOYS; MICROSTRUCTURE; EMBRITTLEMENT; DEFORMATION; ADDITIONS; BEHAVIOR; NI3AL AB The room temperature tensile behavior of Fe-40at.%Al alloys was investigated. Extrusion of both prealloyed powders and castings was performed to produce a wide range of grain sizes for characterization of mechanical properties. In addition, directionally solidified single crystals were also studied. It was found that the influence of processing variables such as extrusion temperature or the form of the starting material (powder vs. cast ingot) on mechanical properties could be explained primarily by their effects on grain size. Grain refinement improved both ductility and strength, whereas rapid quenching after annealing resulted in increases in yield strength and decreases in ductility. The effects of quenching were explained by the evidence of large numbers of quenched-in vacancies. In the binary alloy, fracture was primarily intergranular irrespective of cooling rate, while alloys containing, boron or Zr + B failed transgranularly and maintained their ductility in the rapidly quenched condition. Single crystals oriented in the [100] direction showed evidence of slip behavior yet did not exhibit significant tensile ductility. This lack of ductility was attributed to an early onset of cleavage failure. RP GAYDOSH, DJ (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 28 TC 69 Z9 69 U1 0 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 20 PY 1992 VL 150 IS 1 BP 7 EP 20 DI 10.1016/0921-5093(90)90003-L PG 14 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA HH137 UT WOS:A1992HH13700002 ER PT J AU LEE, CH AF LEE, CH TI MATTER DISTRIBUTION IN A FALSE VACUUM BUBBLE SO MODERN PHYSICS LETTERS A LA English DT Article AB The dynamics of matter distribution that may contaminate a false vacuum bubble is considered. In the case of uniform dust distribution, it is shown that the distribution eventually collapses (expands) if the matter energy density is greater (smaller) than twice the false vacuum energy density. The effect of matter distribution on the dynamics of the bubble wall is discussed. RP LEE, CH (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BOX 500,BATAVIA,IL 60510, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-7323 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD FEB 20 PY 1992 VL 7 IS 5 BP 419 EP 426 DI 10.1142/S0217732392000367 PG 8 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA HG808 UT WOS:A1992HG80800006 ER PT J AU NAGASAWA, M YOKOYAMA, J AF NAGASAWA, M YOKOYAMA, J TI PHASE-TRANSITIONS TRIGGERED BY QUANTUM FLUCTUATIONS IN THE INFLATIONARY UNIVERSE SO NUCLEAR PHYSICS B LA English DT Article ID COSMIC STRINGS; SITTER SPACE; SCALAR FIELD; COSMOLOGY AB The dynamics of a second-order phase transition during inflation, which is induced by time variation of space-time curvature, is studied as a natural mechanism to produce topological defects of typical grand unification scales such as cosmic strings or global textures. It is shown that their energy distribution is almost scale invariant with small- and large-scale cutoffs. Also discussed is how these cutoffs are given. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP NAGASAWA, M (reprint author), UNIV TOKYO,FAC SCI,DEPT PHYS,TOKYO 113,JAPAN. NR 34 TC 23 Z9 23 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD FEB 17 PY 1992 VL 370 IS 2 BP 472 EP 490 DI 10.1016/0550-3213(92)90294-L PG 19 WC Physics, Particles & Fields SC Physics GA HH071 UT WOS:A1992HH07100009 ER PT J AU KRISHNAKUMAR, E SRIVASTAVA, SK AF KRISHNAKUMAR, E SRIVASTAVA, SK TI CROSS-SECTIONS FOR ELECTRON-IMPACT IONIZATION OF O2 SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article DE CROSS-SECTIONS; O2; O2+; ELECTRON IMPACT IONIZATION ID DISSOCIATIVE IONIZATION; ATOMS; OXYGEN; IONS; BEAM; N+; N2 AB Using a crossed electron beam-molecular beam collision geometry and the relative flow technique measurements have been made to generate a uniform set of electron impact ionization cross-section data for O2 for electron impact energies from threshold to 1000eV. Present values of total, partial and dissociative ionization cross-sections are compared with previously published data. Cross-sections for the formation of O2+ from O2 have been measured for the first time. C1 TATA INST FUNDAMENTAL RES,BOMBAY 400005,INDIA. RP KRISHNAKUMAR, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 24 TC 77 Z9 77 U1 2 U2 10 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 FEB 15 PY 1992 VL 113 IS 1 BP 1 EP 12 DI 10.1016/0168-1176(92)87037-F PG 12 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA HG858 UT WOS:A1992HG85800001 ER PT J AU SEN, AD ANICICH, VG AF SEN, AD ANICICH, VG TI SULFUR AND NITROGEN REACTIONS FOR COMETARY COMAE ION CHEMISTRY SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Article DE SULFUR DIOXIDE; CARBON DISULFIDE; HYDRAZINE; ION CYCLOTRON RESONANCE; COMETARY COMAE ID MOLECULE REACTIONS AB The low pressure reactions of sulfur dioxide, carbon disulfide, and hydrazine with H2O+ and H3O+ were studied by the ion cyclotron resonance technique. These reactions are potentially important for sulphur chemistry in cometary comae. Rate coefficients and branching ratios of product channels are presented. RP SEN, AD (reprint author), CALTECH,JET PROP LAB,MS 183-601,4800 OAK GROVE DR,PASADENA,CA 91109, 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 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD FEB 15 PY 1992 VL 113 IS 1 BP 99 EP 104 DI 10.1016/0168-1176(92)87043-E PG 6 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA HG858 UT WOS:A1992HG85800007 PM 11537743 ER PT J AU LIU, WT TANG, WQ WENTZ, FJ AF LIU, WT TANG, WQ WENTZ, FJ TI PRECIPITABLE WATER AND SURFACE HUMIDITY OVER GLOBAL OCEANS FROM SPECIAL SENSOR MICROWAVE IMAGER AND EUROPEAN CENTER FOR MEDIUM RANGE WEATHER FORECASTS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID LATENT-HEAT FLUX; TROPICAL PACIFIC; RADAR ALTIMETER; LEVEL HUMIDITY; SATELLITE DATA; NIMBUS-7 SMMR; VAPOR; MODEL; RADIOMETER; SSM/I AB The two most promising methods of estimating precipitable water W over global oceans rely on spaceborne microwave radiometers and atmospheric general circulation models. Global fields of W from the special sensor microwave imager (SSMI) were compared with those from the European Center for Medium Range Weather Forecasts (ECMWF) model. They agree over most ocean areas; both data sets capture the two annual cycles examined and the interannual anomalies during an E1 Nino-Southern Oscillation episode. However, they show significant differences in the dry air masses over the eastern tropical-subtropical oceans, particularly in the southern hemisphere. In these regions, comparisons with radiosonde data indicate that overestimation by the ECMWF model accounts for a large part of the differences. As a check on the W differences, surface level specific humidity Q derived from W, using a statistical relation, were compared with Q from the ECMWF model. The differences in Q were found to be consistent with the differences in W, and indirectly validating the Q-W relation. In both W and Q, SSMI was able to discern clearly the equatorial extension of the tongues of dry air in the eastern tropical ocean, while both ECMWF and climatological fields have reduced spatial gradients and weaker intensity. One of the reasons for the ECMWF moisture overestimation is suggested to the poor resolution of Tiros-N operational vertical sounder data which were assimilated into the ECMWF model. C1 REMOTE SENSING SYST,SANTA ROSA,CA 95404. RP LIU, WT (reprint author), CALTECH,JET PROP LAB,MS 300-323,PASADENA,CA 91109, USA. NR 31 TC 65 Z9 66 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1992 VL 97 IS C2 BP 2251 EP 2264 DI 10.1029/91JC02615 PG 14 WC Oceanography SC Oceanography GA HE091 UT WOS:A1992HE09100010 ER PT J AU BALCH, W EVANS, R BROWN, J FELDMAN, G MCCLAIN, C ESAIAS, W AF BALCH, W EVANS, R BROWN, J FELDMAN, G MCCLAIN, C ESAIAS, W TI THE REMOTE-SENSING OF OCEAN PRIMARY PRODUCTIVITY - USE OF A NEW DATA COMPILATION TO TEST SATELLITE ALGORITHMS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID PHYTOPLANKTON PRODUCTION; WATER-COLUMN; CHLOROPHYLL; PACIFIC; PIGMENTS; TEMPERATURE; COLOR; SEA; VARIABILITY; ATLANTIC AB We tested global pigment and primary productivity algorithms based on a new data compilation of over 12,000 stations occupied mostly in the northern hemisphere, from the late 1950's to 1988. The results showed high variability of the fraction of total pigment contributed by chlorophyll a (rho), which is required for subsequent predictions of primary productivity. Two models, which predict pigment concentration normalized to attenuation length or euphotic depth, were checked against 2,800 vertical profiles of pigments (chlorophyll a, phaeopigment and total pigment). Phaeopigments consistently showed maxima at about one optical depth below the chlorophyll maxima. We also checked the global Coastal Zone Color Scanner (CZCS; daily 20km resolution) archive for data coincident with the sea truth data. A regression of satellite-derived pigment versus ship-derived pigment had a coefficient of determination (r2) of 0.40 (n = 731 stations). The satellite underestimated the true pigment concentration in mesotrophic and oligotrophic waters (< 1 mg pigment in m-3) and overestimated the pigment concentration in eutrophic waters (> 1 mg pigment m-3). The error in the satellite estimate showed no trends with time between 1978 and 1985. In general the variability of the satellite retrievals increased with pigment concentration. Several productivity algorithms were tested which utilize information on the photoadaptive parameters, biomass and optical parameters for predicting integral production. The most reliable algorithm which explained 67% of the variance in integral production for 1676 stations suggested that future success in deriving primary productivity from remotely sensed data will rely on accurate retrievals of "living" biomass from satellite data, as well as the prediction of at least one photoadaptive parameter such as maximum photosynthesis. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BALCH, W (reprint author), UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,4600 RICKENBACKER CSWY,MIAMI,FL 33149, USA. NR 57 TC 104 Z9 109 U1 2 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1992 VL 97 IS C2 BP 2279 EP 2293 DI 10.1029/91JC02843 PG 15 WC Oceanography SC Oceanography GA HE091 UT WOS:A1992HE09100012 ER PT J AU RODRIGUEZ, E KIM, YJ MARTIN, JM AF RODRIGUEZ, E KIM, YJ MARTIN, JM TI THE EFFECT OF SMALL-WAVE MODULATION ON THE ELECTROMAGNETIC BIAS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GENERATED GRAVITY-WAVES; SURFACE; SEA; SPECTRA; SCATTERING AB The effect of the modulation of small ocean waves by large waves on the physical mechanism of the electromagnetic (EM) bias is examined by conducting a numerical scattering experiment which does not assume the applicability of geometric optics. The modulation effect of the large waves on the small waves is modeled using the principle of conservation of wave action and includes the modulation of gravity-capillary waves. The frequency dependence and magnitude of the EM bias is examined for a simplified ocean spectral model as a function of wind speed. These calculations allow us to assess the validity of previous assumptions made in the theory of the EM bias, with respect to both scattering and hydrodynamic effects. We find that the geometric optics approximation is inadequate for predictions of the EM bias at typical radar altimeter frequencies, while the improved scattering calculations provide a frequency dependence of the EM bias which is in qualitative agreement with observation. We also find that, for typical wind speeds, the EM bias contribution due to small-wave modulation is of the same order as that due to modulation by the nonlinearities of the large-scale waves. RP RODRIGUEZ, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 37 TC 22 Z9 24 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1992 VL 97 IS C2 BP 2379 EP 2389 DI 10.1029/91JC02511 PG 11 WC Oceanography SC Oceanography GA HE091 UT WOS:A1992HE09100020 ER PT J AU KWOK, R RIGNOT, E HOLT, B ONSTOTT, R AF KWOK, R RIGNOT, E HOLT, B ONSTOTT, R TI IDENTIFICATION OF SEA ICE TYPES IN SPACEBORNE SYNTHETIC APERTURE RADAR DATA SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID MICROWAVE SIGNATURES; SUMMER; SCATTEROMETER; ZONE; MELT AB An approach for identification of sea ice types in spaceborne synthetic aperture radar (SAR) image data is presented. The unsupervised classification approach involves cluster analysis for segmentation of the image data followed by cluster labeling based on previously defined look-up tables containing the expected backscatter signatures of different ice types measured by land-based scatterometer. The particular look-up table used for labeling a segmented image is selected based on the seasonal and meteorological conditions at the time of data acquisition. The extensive scatterometer observations and experience accumulated in field campaigns during the last 10 years were used to construct these look-up tables. These tables are expected to evolve as sea ice observations from the European ERS-1 SAR become available. This paper presents the classification approach, its expected performance, the dependence of this performance on radar system performance, and expected ice scattering characteristics. Results using both aircraft and simulated ERS-1 SAR data are presented. The results are compared to limited field ice property measurements and coincident passive microwave imagery. An algorithm based on this experimental approach has been implemented in the geophysical processor system at the Alaska SAR Facility for classification of sea ice data in ERS-1 C band SAR data. The importance of an integrated postlaunch program for validation and improvement of this approach is discussed. C1 ENVIRONM RES INST MICHIGAN,ANN ARBOR,MI 48107. RP KWOK, R (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008; Rignot, Eric/A-4560-2014 OI Kwok, Ron/0000-0003-4051-5896; Rignot, Eric/0000-0002-3366-0481 NR 36 TC 89 Z9 93 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1992 VL 97 IS C2 BP 2391 EP 2402 DI 10.1029/91JC02652 PG 12 WC Oceanography SC Oceanography GA HE091 UT WOS:A1992HE09100021 ER PT J AU TURNER, MS AF TURNER, MS TI DIRAC NEUTRINOS AND SN-1987A SO PHYSICAL REVIEW D LA English DT Article ID HELICITY-FLIPPED NEUTRINOS; E6 PARTICLE MASSES; BETA-SPECTRUM; HEAVY NEUTRINOS; ELECTROWEAK INTERACTIONS; SUPERNOVA 1987A; 17-KEV NEUTRINO; PAIR PRODUCTION; SN1987A SIGNAL; SEARCH AB Within the standard electroweak theory "wrong-helicity" neutrinos are produced in a nascent neutron star by "spin-flip" processes (at a rate proportional to m(nu)2), freely escape, and can lead to an excessively rapid cooling of the newly born neutron star. Previous work, based upon the neutrino-nucleon spin-flip scattering process alone, has shown that the observed cooling of the neutron star associated with SN 1987A excludes a Dirac-neutrino mass greater than approximately 20 keV for either nu(e), nu(mu), or nu(tau). We reexamine the emission of "wrong-helicity" Dirac neutrinos from SN 1987A and conclude that due to neutrino degeneracy and additional emission processes (N + N --> N + N + nu-nuBAR, pi- + p --> n + nu-nuBAR) the effect of a Dirac neutrino on the cooling of SN 1987A has been underestimated. While a precise Dirac-mass limit awaits the incorporation of our new rates into detailed numerical cooling models, we believe that the limit that follows from the cooling of SN 1987A is better, probably much better, than 10 keV. In particular, we believe that SN 1987A definitely excludes a 17-keV (purely) Dirac-mass neutrino that mixes with the electron neutrino at the 1% level. 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), FERMI NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 46 TC 35 Z9 35 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 FEB 15 PY 1992 VL 45 IS 4 BP 1066 EP 1075 DI 10.1103/PhysRevD.45.1066 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HE352 UT WOS:A1992HE35200010 ER PT J AU DODELSON, S JUBAS, JM AF DODELSON, S JUBAS, JM TI REIONIZATION AND DECAYING DARK MATTER SO PHYSICAL REVIEW D LA English DT Article ID MICROWAVE BACKGROUND-RADIATION; H-I REGIONS; MAGNETIC-MOMENT; NEUTRAL HYDROGEN; GALACTIC HALO; UPPER LIMIT; SMALL MASS; NEUTRINOS; CONSTRAINTS; UNIVERSE AB Gunn-Peterson tests suggest that the Universe was reionized after the standard recombination epoch. We present a systematic treatment of the ionization process by deriving the Boltzmann equations appropriate to this regime. A compact solution for the photon spectrum is found in terms of the ionization ratio. These equations are then solved numerically for the decaying-dark-matter scenario, wherein neutrinos with a mass of the order of 30 eV radiatively decay producing photons which ionize the intergalactic medium. We find that the neutrino mass and lifetime are severely constrained by Gunn-Peterson tests, observations of the diffuse photon spectrum in the ultraviolet regime, and the Hubble parameter. C1 MIT, DEPT PHYS, CAMBRIDGE, MA 02139 USA. RP DODELSON, S (reprint author), FERMI NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BOX 500, BATAVIA, IL 60510 USA. NR 70 TC 10 Z9 10 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 EI 1550-2368 J9 PHYS REV D JI Phys. Rev. D PD FEB 15 PY 1992 VL 45 IS 4 BP 1076 EP 1090 DI 10.1103/PhysRevD.45.1076 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HE352 UT WOS:A1992HE35200011 ER PT J AU SALOPEK, DS AF SALOPEK, DS TI COLD-DARK-MATTER COSMOLOGY WITH NON-GUASSIAN FLUCTUATIONS FROM INFLATION SO PHYSICAL REVIEW D LA English DT Article ID DENSITY PERTURBATIONS; UNIVERSE; STRINGS; STATISTICS; EVOLUTION; FIELDS AB Non-Gaussian primordial fluctuations for structure formation may be generated during the inflationary epoch from the nonlinear interaction of two scalar fields with gravity. Semianalytical stochastic inflation calculations are described for nonlinear long-wavelength evolution in 3 + 1 dimensions. Long-wavelength fields are governed by a single equation, the separated Hamilton-Jacobi equation. Typically, non-Gaussian fluctuations arise when the scalar fields pass over a sharp feature in their potential surface. The subsequent evolution of these primordial fluctuations are calculated as scales reenter the horizon during the radiation-dominated and matter-dominated eras of the cold-dark-matter scenario. Contour maps for the linear density perturbation as well as the gravitational potential are displayed at the present epoch. In qualitative agreement with observations, one can construct models with enhanced sheetlike structures on the scale of approximately 25h-1 Mpc. The cleanest test of non-Gaussian fluctuations will hopefully occur in the near future from large-angle microwave-background anisotropy experiments. C1 NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP SALOPEK, DS (reprint author), UNIV CAMBRIDGE,DEPT APPL MATH & THEORET PHYS,SILVER ST,CAMBRIDGE CB3 9EW,ENGLAND. NR 65 TC 60 Z9 60 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 FEB 15 PY 1992 VL 45 IS 4 BP 1139 EP 1157 DI 10.1103/PhysRevD.45.1139 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA HE352 UT WOS:A1992HE35200016 ER PT J AU OHSAKA, K TRINH, EH AF OHSAKA, K TRINH, EH TI ON THE MELTING TEMPERATURES OF LOW-TEMPERATURE PHASES OF POLYMORPHIC METALS SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article RP OHSAKA, K (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 8 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 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB 15 PY 1992 VL 26 IS 4 BP 605 EP 608 DI 10.1016/0956-716X(92)90292-M PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA HD272 UT WOS:A1992HD27200018 ER PT J AU GREEN, S AF GREEN, S TI MOLECULAR CLOUDS - JAMES,RA, MILLAR,TJ SO SCIENCE LA English DT Book Review RP GREEN, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 14 PY 1992 VL 255 IS 5046 BP 858 EP 859 DI 10.1126/science.255.5046.858-a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HD548 UT WOS:A1992HD54800042 PM 17756435 ER PT J AU DOLAN, JF AF DOLAN, JF TI BLACK-HOLES - PLACING FAITH IN THE MASSES SO NATURE LA English DT Editorial Material ID NEUTRON-STARS; MAXIMUM MASS RP DOLAN, JF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 13 PY 1992 VL 355 IS 6361 BP 589 EP 590 DI 10.1038/355589a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HD547 UT WOS:A1992HD54700025 ER PT J AU BURSIK, MI WOODS, AW AF BURSIK, MI WOODS, AW TI CURVED SAPLINGS AT MOUNT ST-HELENS SO NATURE LA English DT Letter C1 INST THEORET GEOPHYS,CAMBRIDGE CB3 9EW,ENGLAND. RP BURSIK, MI (reprint author), CALTECH,JET PROP LAB,MS 183-501,PASADENA,CA 91109, USA. NR 3 TC 2 Z9 2 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 13 PY 1992 VL 355 IS 6361 BP 594 EP 594 DI 10.1038/355594a0 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HD547 UT WOS:A1992HD54700031 ER PT J AU DOWNIE, JD HINE, BP REID, MB AF DOWNIE, JD HINE, BP REID, MB TI EFFECTS AND CORRECTION OF MAGNETOOPTIC SPATIAL LIGHT-MODULATOR PHASE ERRORS IN AN OPTICAL CORRELATOR SO APPLIED OPTICS LA English DT Article ID FILTERS AB Here we study the optical phase errors introduced into an optical correlator by the input and filter plane magneto-optic spatial light modulators. We measure and characterize the magnitude of these phase errors, evaluate their effects on the correlation results, and present a means of correction by a design modification of the binary phase-only optical-filter function. The efficacy of the phase-correction technique is quantified and is found to restore the correlation characteristics to those obtained in the absence of errors, to a high degree. The phase errors of other correlator system elements are also discussed and treated in a similar fashion. RP DOWNIE, JD (reprint author), NASA,AMES RES CTR,MS 244-4,MOFFETT FIELD,CA 94035, USA. NR 11 TC 15 Z9 15 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 10 PY 1992 VL 31 IS 5 BP 636 EP 643 PG 8 WC Optics SC Optics GA HC500 UT WOS:A1992HC50000009 PM 20720659 ER PT J AU BEICHMAN, CA BOULANGER, F MOSHIR, M AF BEICHMAN, CA BOULANGER, F MOSHIR, M TI STAR FORMATION IN TAURUS .1. THE IRAS FAINT SOURCE SURVEY SO ASTROPHYSICAL JOURNAL LA English DT Article DE INFRARED, STARS; ISM, INDIVIDUAL (TAURUS DARK CLOUD); STARS, PRE-MAIN-SEQUENCE; SURVEYS ID CARBON-MONOXIDE EMISSION; YOUNG STELLAR OBJECTS; T-TAURI; MOLECULAR CLOUDS; HEILES CLOUD-2; DENSE CORES; AURIGA; PERSEUS; VIEW; DUST AB A deep infrared survey of a 187 deg2 region in Taurus using the IRAS Faint Source Survey reveals 63 multiband objects selected on the basis of their infrared properties. Two-thirds of the sample are previously uncataloged and are most likely either deeply embedded objects or unidentified T Tauri stars. Complete IRAS data are presented for these objects. The sample is estimated to be more than 90% complete for objects emitting L greater-than-or-equal-to 0.1 L. between 12 and 60-mu-m. The luminosity function shows a decline at luminosities below 0.3 L.. As noted by Kenyon et al., the shape of the luminosity function is difficult to understand in terms of standard models of protostellar accretion. The formation of a massive, 0.1 M., disk of circumstellar material serving as a reservoir for infalling cloud material represents a possible resolution of the problem. A population of unresolved sources emitting only at 60-mu-m is also identified. If any of these objects are self-luminous, they may represent the youngest protostellar objects yet observed. C1 INST ADV STUDY,PRINCETON,NJ 08540. CALTECH,JET PROP LAB,CTR INFRARED PROC & ANAL,PASADENA,CA 91109. ECOLE POLYTECH,F-75230 PARIS 05,FRANCE. NR 43 TC 38 Z9 38 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 248 EP 259 DI 10.1086/171011 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100027 ER PT J AU STEVENS, IR BLONDIN, JM POLLOCK, AMT AF STEVENS, IR BLONDIN, JM POLLOCK, AMT TI COLLIDING WINDS FROM EARLY-TYPE STARS IN BINARY-SYSTEMS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, GENERAL; STARS, INDIVIDUAL (V444-CYG, HD-193793); STARS, MASS LOSS; STARS, WOLF-RAYET; X-RAYS, STARS ID WOLF-RAYET STARS; RADIATIVE SHOCK-WAVES; X-RAY; STELLAR WINDS; ZETA AURIGAE; EMISSION; MODELS; INSTABILITIES; V444-CYGNI; IONIZATION AB The collision of massive, supersonic stellar winds in early-type binary systems will produce a substantial flux of soft X-rays from the shock-heated material in the wind interaction region. In this paper we study the dynamics of the wind and shock structure formed by the wind collision. We employ a two-dimensional hydro-dynamics code, which self-consistently accounts for radiative cooling, and represents a significant improvement over previous attempts to model these systems. We calculate the X-ray luminosity and spectra of the shock-heated region, accounting for wind attenuation and the influence of different abundances on the resultant level and spectra of X-ray emission. We also examine a variety of dynamical instabilities that are found to dominate the intershock region. These instabilities are found to be particularly important when postshock material is able to cool. These instabilities disrupt the postshock flow and add a time variability of order 10% to the X-ray luminosity. The X-ray spectrum of these systems is found to vary with the nuclear abundances of the winds, which can be very nonsolar in the case of Wolf-Rayet stars. We use these theoretical models to study several massive binary systems, in particular V444 Cyg and HD 193793. C1 UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. UNIV VIRGINIA,DEPT ASTRON,CHARLOTTESVILLE,VA 22903. COMP & SCI CO LTD,SHEFFIELD S11 7EY,ENGLAND. RP STEVENS, IR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 53 TC 413 Z9 413 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 265 EP 287 DI 10.1086/171013 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100029 ER PT J AU HOLLIS, JM DORBAND, JE YUSEFZADEH, F AF HOLLIS, JM DORBAND, JE YUSEFZADEH, F TI COMPARING RESTORED HST AND VLA IMAGERY OF R-AQUARII SO ASTROPHYSICAL JOURNAL LA English DT Article DE CIRCUMSTELLAR MATTER; ISM, STRUCTURE; STARS, INDIVIDUAL (R-AQUARII); TECHNIQUES, IMAGE PROCESSING ID MAXIMAL ENTROPY; SIO MASER; ALGORITHM; CONTINUUM; NEBULA AB The maximum entropy method is applied to Hubble Space Telescope data taken of the R Aquarii binary system and its jet with the Faint Object Camera in order to restore an image in [O III] at 5007 angstrom plagued by spherical aberration and detector saturation. These results are compared with 2 cm radio continuum imagery taken with the Very Large Array at the same limiting resolution of approximately 0".1. The comparison suggests that shock excitation of the inner jet accounts for a spatial difference between the [O III] and radio continuum emission regions. C1 NORTHWESTERN UNIV,DEPT PHYS & ASTRON,EVANSTON,IL 60201. RP HOLLIS, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DIV SPACE DATA & COMP,CODE 390,GREENBELT,MD 20771, USA. NR 22 TC 30 Z9 30 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 293 EP & DI 10.1086/171015 PN 1 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100031 ER PT J AU PREECE, RD HARDING, AK AF PREECE, RD HARDING, AK TI RESONANT COMPTON COOLING AND ANNIHILATION LINE PRODUCTION IN GAMMA-RAY BURSTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, BURSTS; LINE, FORMATION; RADIATION MECHANISMS, COMPTON AND INVERSE COMPTON ID STRONG MAGNETIC-FIELDS; SYNCHROTRON RADIATION; THOMSON SCATTERING; PAIR ANNIHILATION; SPECTRA; EMISSION; PLASMAS; ABSORPTION; ELECTRONS; PHOTONS AB A synchrotron self-Compton emission model for gamma-ray bursts is presented which produces narrow annihilation features for a variety of field strengths, primary electron injection energies, and injection rates. In this model, energetic primary electrons are injected and cooled by synchrotron emission in a strong, homogeneous magnetic field, resulting in a pair cascade. Multiple resonant scattering with cyclotron photons efficiently traps and cools pairs in the ground state to an average energy where the Compton energy loss rate is zero, which is in agreement with previous estimates of a Compton temperature. This Compton energy is determined by the shape of the photon spectrum, which itself changes as the particles cool, so a self-consistent solution must be found iteratively. The particle distributions in the ground state are determined by numerically solving the Fokker-Planck equation in the steady state. Annihilation between pairs in these cooled distributions can be very efficient. In the case of isotropic injection of primary electrons, a significant narrow-line feature appears in the overall emission. In the case of beamed injection, the annihilation line is broadened to the extent that it would not be observable. Our prediction of an anticorrelation between narrow annihilation features and continuum emission above 1 MeV could be confirmed by the BATSE spectroscopy detectors on the Compton Gamma-Ray Observatory. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP PREECE, RD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,E562,HUNTSVILLE,AL 35812, USA. RI Harding, Alice/D-3160-2012; OI Preece, Robert/0000-0003-1626-7335 NR 45 TC 1 Z9 1 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 308 EP 324 DI 10.1086/171017 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100033 ER PT J AU REUTER, DC AF REUTER, DC TI THE CONTRIBUTION OF METHANOL TO THE 3.4-MICRON EMISSION FEATURE IN COMETS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COMETS, GENERAL; LINE, IDENTIFICATION; MOLECULAR PROCESSES ID ORGANIC GRAINS; MU-M; HALLEY; SPECTROSCOPY; FORMALDEHYDE; DISCOVERY; SPECTRUM; P/HALLEY; WILSON; FIELD AB In this paper a fluorescence model for cometary emission in the nu(2), nu(3), and nu(9) bands of methanol is described. This model is used in conjunction with observed spectra of several comets to determine the possible contribution of CH3OH to the frequently seen 3.4-mu-m "cometary organic" feature. For comets P/Halley and Wilson, methanol production rates are retrieved from the flux in the nu(3) band centered at approximately 3.52-mu-m. RP REUTER, DC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,CODE 693,GREENBELT,MD 20771, USA. NR 25 TC 25 Z9 25 U1 1 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 FEB 10 PY 1992 VL 386 IS 1 BP 330 EP 335 DI 10.1086/171019 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100035 ER PT J AU POTGIETER, MS LEROUX, JA AF POTGIETER, MS LEROUX, JA TI THE SIMULATED FEATURES OF HELIOSPHERIC COSMIC-RAY MODULATION WITH A TIME-DEPENDENT DRIFT MODEL .1. GENERAL EFFECTS OF THE CHANGING NEUTRAL SHEET OVER THE PERIOD 1985-1990 SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC RAYS; INTERPLANETARY MEDIUM; SUN, ACTIVITY ID SOLAR MODULATION; MAGNETIC-FIELD; OUTER HELIOSPHERE AB The heliospheric modulation of galactic cosmic rays is simulated with a time-dependent drift model with emphasis on the effects of the wavy heliospheric neutral sheet (HNS) as a function of time during the period 1985-1990. This was done by assuming the outward propagating HNS as the only time-dependent parameter which made it possible to establish to what extent the HNS could have been dominating the modulation process during this period. The model predicted a clearly defined time difference between the time when minimum modulation occurred at Earth and at radial distances farther away from the Sun, indicating that the HNS plays an important part in establishing this observed time delay. The movements of the Voyager 1 (V1) and 2 (V2) and Pioneer 10 (P10) spacecraft were simulated in order to calculate instantaneous radial and latitudinal gradients. The time dependencies of these gradients were found to follow the observations well; the radial gradient between the simulated P10 and 1 AU varied from 2.7% AU-1 in the early simulated 1985 to 2.1% AU-1 at minimum modulation after when it increased rapidly to 3.1% AU-1 reaching a maximum of almost 4% AU-1 at maximum HNS waviness. The calculated radial gradient between the simulated V2 and P10 was found smaller, varying from approximately 2.5% AU-1 in 1985, to 1.1% AU-1 in 1987, to approximately 3.2% AU-1 in 1989, indicating that the predicted radial gradient decreased with increasing radial distance during the period considered. Unfortunately, the model predicted the modulation and therefore the radial gradients too large during periods of high solar activity. The predicted instantaneous "latitudinal gradient" between the simulated movements for V1 and V2 was found to vary between a small positive value in early 1985 to -0.85% deg-1 at minimum modulation, with a rapid increase after this period to +0.8% deg-1 in 1989. This kind of compatibility with observations supports therefore the view that the HNS was probably responsible for establishing the underlying latitude-dependence of heliospheric modulation for the period and energies considered. The role of K perpendicular-to and a modification of the heliospheric polar magnetic field were also studied and showed that a small K perpendicular-to almost-equal-to 6.6 x 10(19) cm2 s-1 for 1 GV particles at Earth was required to obtain reasonable latitudinal gradients. The modification to the Parker spiral field was found to play a moderate role but might become more important with increased solar activity. Since the model predicted the modulation after 1987 too large due to the extraordinary rapid increase in the HNS waviness, we came to the conclusion that additional time-dependent parameters or features would have to be incorporated to explain this period. The model study nevertheless contributes to the growing evidence that the HNS cannot be ignored, especially during periods of low to moderate solar activity, when the modulation of cosmic rays is described. C1 UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLLEGE PK,MD 20742. RP POTGIETER, MS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 692,GREENBELT,MD 20771, USA. NR 36 TC 67 Z9 67 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 336 EP 346 DI 10.1086/171020 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100036 ER PT J AU BROSIUS, JW WILLSON, RF HOLMAN, GD SCHMELZ, JT AF BROSIUS, JW WILLSON, RF HOLMAN, GD SCHMELZ, JT TI CORONAL MAGNETIC-STRUCTURES OBSERVING CAMPAIGN .4. MULTIWAVEBAND OBSERVATIONS OF SUNSPOT AND PLAGE-ASSOCIATED CORONAL EMISSION SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, CORONA; SUN, PLAGES; SUN, RADIO RADIATION; SUN, X-RAYS, GAMMA-RAYS; SUNSPOTS ID SOLAR ACTIVE REGIONS; LARGE ARRAY OBSERVATIONS; THERMAL CYCLOTRON LINE; X-RAY; VLA OBSERVATIONS; MICROWAVE EMISSION; LOOPS; WAVELENGTH; FIELDS AB Simultaneous observations of an active region located near central meridian were obtained with the Very Large Array, the Solar Maximum Mission X-Ray Polychromator, and the Beijing Observatory magnetograph on 1987 December 18, during the Coronal Magnetic Structures Observing Campaign (CoMStOC). An asymmetric looplike structure connects the strong leading sunspot with a nearby region of opposite polarity. Both 6 and 20 cm emission lie along this structure, rather than over the sunspot, with higher frequency emission originating closer to the footpoint inside the sunspot. The 20 cm emission is due to a superposition of second- and third-harmonic gyroemission, where the field strength is 160-300 G, while the 6 cm emission is due to third-harmonic gyroemission from a region where the magnetic field strength ranges from 547 to 583 G. A high value of the Alfven speed, approximately 40,000 km s-1, is obtained at the location of the 6 cm source, with somewhat lower values, approximately 10,000-20,000 km s-1, at the location of the 20 cm emission. At the location of the 6 cm source, the plasma temperature diminishes with height from 2.5 x 10(6) K at approximately 5000 km to 1.3 x 10(6) K at approximately 15,000 km. The X-ray data associated with an area of trailing plage were used to predict the brightness temperature structure due to thermal bremsstrahlung emission in the 6 and 20 cm wavebands. The predicted 6 cm brightness temperature in and around the location of the X-ray peak is low, consistent with our lack of observed 6 cm plage emission. The predicted 20 cm brightness temperature is consistent with that observed in the central portions of the page, but the high 20 cm polarization requires the presence of cool (T(e) less-than-or-equal-to 5 x 10(5) K), absorbing plasma overlying the hot plasma observed in X-rays. Two different models for interpreting these observations are described. C1 TUFTS UNIV,DEPT PHYS & ASTRON,MEDFORD,MA 02134. LOCKHEED MISSILES & SPACE CO INC,SUNNYVALE,CA 94086. RP BROSIUS, JW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 6821,GREENBELT,MD 20771, USA. RI Holman, Gordon/C-9548-2012 NR 33 TC 41 Z9 41 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1992 VL 386 IS 1 BP 347 EP 358 DI 10.1086/171021 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC501 UT WOS:A1992HC50100037 ER PT J AU BERTIGER, WI WU, JT WU, SC AF BERTIGER, WI WU, JT WU, SC TI GRAVITY-FIELD IMPROVEMENT USING GLOBAL POSITIONING SYSTEM DATA FROM TOPEX POSEIDON - A COVARIANCE ANALYSIS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID MODEL AB The TOPEX/Poseidon satellite (inclination 65-degrees, period 113 min) is scheduled for launch in 1992 to study the world's ocean topography through precise altimetric measurements. It will also carry an experimental Global Positioning System (GPS) receiver to demonstrate precise orbit determination with GPS. Data for the GPS experiment will be collected by the on-board receiver and a worldwide network of ground receivers. These data may also be used to improve the knowledge of the Earth's gravitational field. The GPS data are especially useful for improving the gravity field over the world's oceans, where the current tracking data are sparse. Using a realistic scenario for processing 10 days of GPS data, we perform a covariance analysis to obtain the expected improvement to the GEM-T2 gravity field. The large amount of GPS data and the large number of parameters (1979 parameters for the gravity field, plus carrier phase biases, etc.) require special filtering techniques for efficient solution. We have used the gravity bin technique introduced earlier to compute the covariance matrix associated with the spherical harmonic gravity field. The covariance analysis shows that the GPS data from one 10-day arc of TOPEX/Poseidon with no a priori constraints can resolve medium degree and order (3-26) parameters with sigmas (standard deviations) that are an order of magnitude smaller than the corresponding sigmas of GEM-T2. When the information from GEM-T2 is combined with the TOPEX/Poseidon GPS measurements, an order of magnitude improvement is observed in low- and medium-degree terms with significant improvements spread over a wide range of degree and order. RP BERTIGER, WI (reprint author), CALTECH,JET PROP LAB,TRACKING SYST & APPLICAT SECT,MAIL STOP 238-624,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 18 TC 6 Z9 6 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1992 VL 97 IS B2 BP 1965 EP 1971 DI 10.1029/91JB02563 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HD477 UT WOS:A1992HD47700022 ER PT J AU WU, JT YUNCK, TP AF WU, JT YUNCK, TP TI TOPEX ORBIT DETERMINATION AND GRAVITY RECOVERY USING GLOBAL POSITIONING SYSTEM DATA FROM REPEAT ORBITS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID TRACKING AB A covariance analysis is presented for satellite tracking and gravity recovery with a differential Global Positioning System-based technique to be demonstrated on TOPEX in the early 1990s. The technique employs data from an ensemble of repeat ground tracks to recover a unique satellite epoch state for each track and a set of invariant positional parameters common to all tracks. The positional parameters represent the effect of mismodeled gravitational field on the satellite orbit. At an altitude of 1336 km, where gravity modeling is the dominant systematic error, averaging of random error over many arcs and adjustment of the gravity model reduce the final satellite position error. The positional parameters can then be used to produce a refined global gravity model. The analysis indicates that errors ranging from 5 to 8 cm in TOPEX altitude and 0.05 to 0.2 mGal for the gravity field can be achieved, depending on the number of repeat arcs used. RP WU, JT (reprint author), CALTECH,JET PROP LAB,TRACKING SYST & APPLICAT SECT,MAIL STOP 238-625,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 26 TC 4 Z9 5 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-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1992 VL 97 IS B2 BP 1973 EP 1979 DI 10.1029/91JB02562 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HD477 UT WOS:A1992HD47700023 ER PT J AU GORSKI, KM SILK, J VITTORIO, N AF GORSKI, KM SILK, J VITTORIO, N TI COLD DARK MATTER CONFRONTS THE COSMIC MICROWAVE BACKGROUND - LARGE-ANGULAR-SCALE ANISOTROPIES IN OMEGA-0+LAMBDA=1 MODELS SO PHYSICAL REVIEW LETTERS LA English DT Article ID UNIVERSE AB We use a new technique to compute the correlation function for large-angle cosmic microwave background anisotropies resulting from both the space and time variations in the gravitational potential in flat, vacuum-dominated, cold dark matter cosmological models. Such models with OMEGA-0 is-similar-to 0.2 fit the excess power, relative to the standard cold dark matter model. observed in the large-scale galaxy distribution and allow a high value for the Hubble constant. The low order multipoles and quadrupole anisotropy that are potentially observable by COBE and other ongoing experiments should definitively test these models. C1 INST ADV STUDY,SCH NAT SCI,PRINCETON,NJ 08540. UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV LAQUILA,DIPARTMENTO FIS,I-67100 LAQUILA,ITALY. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP GORSKI, KM (reprint author), PRINCETON UNIV,DEPT ASTROPHYS SCI,PEYTON HALL,PRINCETON,NJ 08544, USA. NR 9 TC 33 Z9 33 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 10 PY 1992 VL 68 IS 6 BP 733 EP 736 DI 10.1103/PhysRevLett.68.733 PG 4 WC Physics, Multidisciplinary SC Physics GA HC505 UT WOS:A1992HC50500003 ER PT J AU POKELA, PJ KOLAWA, E RUIZ, R REID, JS NICOLET, MA AF POKELA, PJ KOLAWA, E RUIZ, R REID, JS NICOLET, MA TI THERMAL-STABILITY AND THE FAILURE MECHANISM OF THE AL/W76N24/AU METALLIZATION SO THIN SOLID FILMS LA English DT Article ID DIFFUSION; SYSTEM; SI AB We have studied amorphous binary W76N24 thin films as diffusion barriers between aluminum (170 nm) and gold films for variable gold (170 nm, 620 nm) and W76N24 (80-280 nm) thicknesses. The thermal stability of Al/W76N24/Au trilayers is evaluated using 3 MeV H-4(2+) backscattering spectrometry, Read camera X-ray diffraction, scanning electron microscopy together with energy-dispersive analysis of X-rays, and optical microscopy. A 280 nm thick W76N24 film prevents the interaction between the aluminum underlayers and the gold overlayer, both 170 nm thick, for annealings of 30 min in vacuum up to 500-degrees-C, as observed by backscattering. At elevated temperatures, the integrity of the metallization degrades further in a localized manner which is attributed to the growth of Al-Au or Al-W intermetallic in the interface between the aluminum and W76N24 films. Metallizations with 80 nm or 140 nm thick diffusion barriers fail already after 30 min annealings at 450-degrees-C or 500-degrees-C respectively, according to analyses by backscattering. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP POKELA, PJ (reprint author), CALTECH,PASADENA,CA 91125, USA. NR 10 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD FEB 10 PY 1992 VL 208 IS 1 BP 33 EP 37 DI 10.1016/0040-6090(92)90943-6 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA HH883 UT WOS:A1992HH88300008 ER PT J AU SODUPE, M BAUSCHLICHER, CW LEE, TJ AF SODUPE, M BAUSCHLICHER, CW LEE, TJ TI THE CALCULATION OF THE VIBRATIONAL FREQUENCIES OF CUCO+, NICO AND CUCH3 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRON CORRELATION; POSITIVE-IONS; ROW ATOMS; ABINITIO; NICKEL; INTENSITIES; MOLECULES; CARBONYLS; FE(CO)5; 1ST-ROW AB The vibrational frequencies of CuCO+, NiCO, and CuCH3 are computed at both the self-consistent-field (SCF) and coupled-cluster singles and doubles, with a perturbational estimate of the triples (CCSD(T)), levels of theory. Overall the SCF frequencies are in qualitative agreement with the CCSD(T) results. The calculations show that the frequencies for the electrostatically bound CuCO+ are quite different from the datively bound NiCO. The CCSD(T) calculations support a previous suggestion that the C-H stretches in CuCH3 have been misassigned. RP SODUPE, M (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Lee, Timothy/K-2838-2012; Sodupe, Mariona/E-9352-2013 OI Sodupe, Mariona/0000-0003-0276-0524 NR 37 TC 50 Z9 50 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 7 PY 1992 VL 189 IS 3 BP 266 EP 272 DI 10.1016/0009-2614(92)85137-Y PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA HD950 UT WOS:A1992HD95000014 ER PT J AU THOMPSON, TW GOLDSTEIN, RM CAMPBELL, DB STANSBERY, EG POTTER, AE AF THOMPSON, TW GOLDSTEIN, RM CAMPBELL, DB STANSBERY, EG POTTER, AE TI RADAR DETECTION OF CENTIMETER-SIZED ORBITAL DEBRIS - PRELIMINARY ARECIBO OBSERVATIONS AT 12.5-CM WAVELENGTH SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Orbital debris objects with sizes of 6 mm and larger were detected when they passed through the main beam of the high-power, 12.6-cm wavelength radar at the Arecibo Observatory. The number of objects detected at altitudes below 1000 km in the size range of 6 mm to 2 cm agreed with orbital debris model predictions to better than a factor of two. Radar detections of larger orbital debris (10-cm diameter and above) were also compared with the objects in the U.S. Space Command catalog (the cataloged objects have UHF radar cross-sections larger than 0.01 m2). This experiment demonstrated that the large, Earth-based radar telescopes normally used for planetary studies can provide useful data about the near-Earth orbital debris populations. C1 CORNELL UNIV,NATL ASTRON & IONOSPHER CTR,ITHACA,NY 14853. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP THOMPSON, TW (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 3 TC 9 Z9 9 U1 2 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 7 PY 1992 VL 19 IS 3 BP 257 EP 259 DI 10.1029/91GL02772 PG 3 WC Geosciences, Multidisciplinary SC Geology GA HC979 UT WOS:A1992HC97900010 ER PT J AU MCCORMICK, MP VEIGA, RE CHU, WP AF MCCORMICK, MP VEIGA, RE CHU, WP TI STRATOSPHERIC OZONE PROFILE AND TOTAL OZONE TRENDS DERIVED FROM THE SAGE-I AND SAGE-II DATA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB SAGE I/II ozone data from the period 1979-1991 have been used to derive global trends in both stratospheric column ozone and as a function of altitude. A statistical model containing quasibiennial, seasonal, and semiannual oscillations, a linear component, and a first-order autoregressive noise process was fit to the time series of SAGE I/II monthly zonal mean data. The linear trend in column ozone above 17 km altitude, averaged between 65-degrees-S and 65-degrees-N, is -0.30 +/- 0.19%/year or -3.6% over the time period February 1979 through April 1991. The data further show that the column trend above 17 km is nearly zero in the tropics and increases towards the high latitudes with values of -0.6%/year at 60-degrees-S and -0.35%/year at 60-degrees-N. Both these results are in agreement with the recent TOMS results. Furthermore, the profile trend analyses show the column ozone losses are occurring below 25 km, with most of the loss coming from the region between 17 and 20 km. Negative trend values on the order of -2%/year are found at 17 km in mid-latitudes. C1 HUGHES STX CORP,HAMPTON,VA 23666. RP MCCORMICK, MP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 475,HAMPTON,VA 23665, USA. NR 5 TC 90 Z9 93 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 7 PY 1992 VL 19 IS 3 BP 269 EP 272 DI 10.1029/92GL00187 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HC979 UT WOS:A1992HC97900013 ER PT J AU JEBENS, DS LAKKARAJU, HS MCKAY, CP BORUCKI, WJ AF JEBENS, DS LAKKARAJU, HS MCKAY, CP BORUCKI, WJ TI TIME RESOLVED SIMULATION OF LIGHTNING BY LIP SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LASER-INDUCED PLASMAS; PLANETARY-ATMOSPHERES; NITROGEN; TITAN; AEROSOLS; FIXATION; JUPITER; VENUS AB In this letter, we report results of time resolved spectra of lightning simulation in air by laser-induced plasma (LIP). The measured electron temperatures varied from (1.7 +/- 0.1)X10(4) K at 600 ns to (1.2 +/- 0.1)X10(4) K at 4-mu-s after the ignition of the plasma. Electron densities in the plasma varied from (7.0 +/- 1.4)X10(17)/cm3 to (9.0 +/- 1.8)X10(16)/cm3 for the above times.. We also present, for the first time, a comparison of state variables for LIP and natural lightning. We find that immediately following the ignition both natural lightning and LIP reach temperatures in excess of 16,000 K and relax to ambient pressure with different rates. They are expected to approach 2000 - 4000 K temperature range, which is important to chemical synthesis, in an asymptotically similar fashion. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP JEBENS, DS (reprint author), SAN JOSE STATE UNIV,DEPT PHYS,SAN JOSE,CA 95192, USA. FU NCI NIH HHS [NCA2-508, NCA2-382]; PHPPO CDC HHS [PHY-9000697] NR 23 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 7 PY 1992 VL 19 IS 3 BP 273 EP 276 DI 10.1029/91GL02937 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HC979 UT WOS:A1992HC97900014 PM 11538394 ER PT J AU PICKERING, KE SCALA, JR THOMPSON, AM TAO, WK SIMPSON, J AF PICKERING, KE SCALA, JR THOMPSON, AM TAO, WK SIMPSON, J TI A REGIONAL ESTIMATE OF CONVECTIVE-TRANSPORT OF CO FROM BIOMASS BURNING SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AMAZONIA; TROPICS; OZONE; O3 AB We present a regional-scale estimate of the fraction of biomass burning emissions that are transported to the free troposphere by deep convection. The focus is on CO and the study region is a part of Brazil that underwent intensive deforestation in the 1980's. The method of calculation is stepwise, scaling up from a prototype convective event, the dynamics of which are well-characterized, to the vertical mass flux of carbon monoxide over the region. Satellite-derived observations of the areal extent of pollution from biomass burning and convective cloud cover are used in the scaling. Given uncertainties in CO emissions from biomass burning and the representativeness of the protoype event, it is estimated that 10-40 percent of CO emissions from the burning region may be rapidly transported to the free troposphere over the burning region. These relatively fresh emissions will produce O3 efficiently in the free troposphere where O3 has a longer lifetime than in the boundary layer. RP PICKERING, KE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,ATMOSPHERES LAB,CODE 916,GREENBELT,MD 20771, USA. RI Pickering, Kenneth/E-6274-2012; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 17 TC 32 Z9 32 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 7 PY 1992 VL 19 IS 3 BP 289 EP 292 DI 10.1029/92GL00036 PG 4 WC Geosciences, Multidisciplinary SC Geology GA HC979 UT WOS:A1992HC97900018 ER PT J AU BRIMHALL, GH CHADWICK, OA LEWIS, CJ COMPSTON, W WILLIAMS, IS DANTI, KJ DIETRICH, WE POWER, ME HENDRICKS, D BRATT, J AF BRIMHALL, GH CHADWICK, OA LEWIS, CJ COMPSTON, W WILLIAMS, IS DANTI, KJ DIETRICH, WE POWER, ME HENDRICKS, D BRATT, J TI DEFORMATIONAL MASS-TRANSPORT AND INVASIVE PROCESSES IN SOIL EVOLUTION SO SCIENCE LA English DT Article ID METAL ENRICHMENT; ATACAMA DESERT; NORTHERN CHILE; LA-ESCONDIDA; CALIFORNIA; AUSTRALIA; BAUXITES AB Soils are differentiated vertically by coupled chemical, mechanical and biological transport processes. Soil properties vary with depth, depending on the subsurface stresses, the extent of mixing, and the balance between mass removal in solution or suspension and mass accumulation near the surface. Channels left by decayed roots and burrowing animals allow organic and inorganic detritus and precipitates to move through the soil from above. Accumulation occurs at depths where small pores restrict further passage. Consecutive phases of translocation and root growth stir the soil; these processes constitute an invasive dilatational process that leads to positive cumulative strains. In contrast, below the depth of root penetration and mass additions, mineral dissolution by descending organic acids leads to internal collapse under overburden load. This softened and condensed precursor horizon is transformed into soil by biological activity, which stirs and expands the evolving residuum by invasion by roots and macropore networks that allows of materials from above. C1 AUSTRALIAN NATL UNIV,RES SCH EARTH SCI,CANBERRA,ACT 2601,AUSTRALIA. BHP UTAH INT MET,SAN FRANCISCO,CA 94104. UNIV CALIF BERKELEY,DEPT INTEGRAT BIOL,BERKELEY,CA 94720. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV ARIZONA,DEPT SOIL & WATER SCI,TUCSON,AZ 85721. RP BRIMHALL, GH (reprint author), UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720, USA. RI SHRIMP, ANU/F-5312-2011; Williams, Ian/F-4302-2012 OI Williams, Ian/0000-0003-4465-6493 NR 40 TC 118 Z9 123 U1 2 U2 30 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 7 PY 1992 VL 255 IS 5045 BP 695 EP 702 DI 10.1126/science.255.5045.695 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HC506 UT WOS:A1992HC50600032 PM 17756948 ER PT J AU CROWLEY, TJ KIM, KY MENGEL, JG SHORT, DA AF CROWLEY, TJ KIM, KY MENGEL, JG SHORT, DA TI MODELING 100,000-YEAR CLIMATE FLUCTUATIONS IN PRE-PLEISTOCENE TIME-SERIES SO SCIENCE LA English DT Article ID ICE AGES; RECORD; QUATERNARY; SEDIMENTS AB A number of pre-Pleistocene climate records exhibit significant fluctuations at the 100,000-year (100-ky) eccentricity period, before the time of such fluctuations in global ice volume. The origin of these fluctuations has been obscure. Results reported here from a modeling study suggest that such a response can occur over low-latitude land areas involved in monsoon fluctuations. The twice yearly passage of the sun across the equator and the seasonal timing of perihelion interact to increase both 100-ky and 400-ky power in the modeled temperature field. The magnitude of the temperature response is sufficiently large to leave an imprint on the geologic record, and simulated fluctuations resemble those found in records of Triassic lake levels. C1 APPL RES CORP,LANDOVER,MD 20785. NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. RP CROWLEY, TJ (reprint author), APPL RES CORP,305 ARGUELLO DR,COLLEGE STN,TX 77840, USA. NR 31 TC 58 Z9 60 U1 2 U2 9 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 7 PY 1992 VL 255 IS 5045 BP 705 EP 707 DI 10.1126/science.255.5045.705 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HC506 UT WOS:A1992HC50600034 PM 17756950 ER PT J AU BRAINERD, JJ AF BRAINERD, JJ TI GAMMA-RAY BURSTS IN THE GALACTIC HALO SO NATURE LA English DT Article ID ABSORPTION; FEATURES; PULSARS AB THE angular and luminosity distributions of the gamma-ray bursts observed by the BATSE instrument, on the Gamma Ray Observatory satellite, cannot be explained by sources confined to the galactic plane 1. Instead the observations are consistent with a nearly isotropic source density that falls with distance. Although this permits a cosmological origin, it also permits an origin in the halo of our Galaxy, preserving some aspects of models in which galactic neutron stars are the sites of the bursts. I show here that significant isotropy can be achieved with a spherically symmetric halo model if it extends out beyond 100 kpc. Large halo core radii enhance isotropy, although consistency with observation is possible for core radii as small as 5 kpc if the halo radius is sufficiently large. The intrinsic luminosity distribution of gamma-ray bursts must be treated as a free parameter to fit the observations. If gamma-ray bursts are from the halo, they are likely to be old population II neutron stars, because models based on pulsars escaping from the galactic plane have strong anisotropies. RP BRAINERD, JJ (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES-65,HUNTSVILLE,AL 35812, USA. NR 19 TC 45 Z9 45 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 6 PY 1992 VL 355 IS 6360 BP 522 EP 524 DI 10.1038/355522a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HC526 UT WOS:A1992HC52600049 ER PT J AU PRATHER, MJ AF PRATHER, MJ TI MORE RAPID POLAR OZONE DEPLETION THROUGH THE REACTION OF HOCL WITH HCL ON POLAR STRATOSPHERIC CLOUDS SO NATURE LA English DT Article ID ANTARCTIC SPRING VORTEX; CHLORINE NITRATE; HETEROGENEOUS CHEMISTRY; HYDROGEN-CHLORIDE; NITRIC-ACID; N2O5; SURFACES; ICE; TEMPERATURES; COEFFICIENTS AB THE direct reaction of HOCl with HCl, known to occur in liquid water 1 and on glass surfaces 2, has now been measured on surfaces similar to polar stratospheric clouds 3,4 and is shown here to play a critical part in polar ozone loss. Two keys to understanding the chemistry of the Antarctic ozone hole 5-7 are, one, the recognition that reactions on polar stratospheric clouds transform HCl into more reactive species denoted by ClO(x) (refs 8-12) and, two, the discovery of the ClO-dimer (Cl2O2) mechanism that rapidly catalyses destruction of O3 (refs 13-15). Observations of high levels of OClO and ClO in the springtime Antarctic stratosphere 16-19 confirm that most of the available chlorine is in the form of ClO(x) (refs 20, 21). But current photochemical models 22,23 have difficulty converting HCl to ClO(x) rapidly enough in early spring to account fully for the observations 5-7,20,21. Here I show, using a chemical model, that the direct reaction of HOCl with HCl provides the missing mechanism. As alternative sources of nitrogen-containing oxidants, such as N2O5 and ClONO2, have been converted in the late autumn to inactive HNO3 by known reactions on the sulphate-layer aerosols 24-27, the reaction of HOCl with HCl on polar stratospheric clouds becomes the most important pathway for releasing that stratospheric chlorine which goes into polar night as HCl. RP PRATHER, MJ (reprint author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 44 TC 63 Z9 64 U1 0 U2 8 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD FEB 6 PY 1992 VL 355 IS 6360 BP 534 EP 537 DI 10.1038/355534a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA HC526 UT WOS:A1992HC52600054 ER PT J AU NOEVER, DA AF NOEVER, DA TI STATISTICS OF EMULSION LATTICES SO COLLOIDS AND SURFACES LA English DT Article DE COARSENING; EMULSION LATTICES; RANDOM PATTERNS; STATISTICAL CRYSTALLOGRAPHY; TOPOLOGY AB The statistics of emulsion lattices - nearly two-dimensional (2D) oil-in-water emulsions - are analyzed using statistical crystallography. Strict mathematical requirements determine the 2D topology, such that random partitioning of space yields a predictable statistical geometry for polygon shapes. For all lattices examined, Aboav's and Lewis's laws are verified; this result is consistent both with the need to fill 2D space and with energy carried not exclusively by pattern boundaries. The aim is synthetic; together, the crystallographic results suggest a universality akin to statistical equations of state which govern emulsions and hence unite their geometric coarsening to other random networks such as froths, magnetic bubbles and acidic monolayers. RP NOEVER, DA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES-76,HUNTSVILLE,AL 35812, USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-6622 J9 COLLOID SURFACE PD FEB 5 PY 1992 VL 62 IS 3 BP 243 EP 247 DI 10.1016/0166-6622(92)80006-N PG 5 WC Chemistry, Physical SC Chemistry GA HF664 UT WOS:A1992HF66400006 ER PT J AU ALDRICH, A ROSEN, R CRAIG, M MANKINS, JC AF ALDRICH, A ROSEN, R CRAIG, M MANKINS, JC TI EXPLORATION TECHNOLOGY PROGRAM PLANS AND DIRECTIONS SO ACTA ASTRONAUTICA LA English DT Article AB During the first part of the next century, the United States will return to the Moon to create a permanent lunar base, and, before the year 2019, we will send a human mission to Mars. In addition to these human operations, the Space Exploration Initiative will integrally incorporate robotic lunar and Mars missions. In achieving these efforts to expand human presence and activity in space and also exerted and frontiers of human knowledge, the SEI will require an array of new technologies. Mission architecture definition is still underway, but previous studies indicate that the SEI will require developments in areas such as advanced engines for space transportation, in-space assembly and construction to support permanent basing of exploration systems in space, and advanced surface operations capabilities including adequate levels of power and surface roving vehicles, and technologies to support safely long-duration human operations in space. Plans are now being put into place to implement an Exploration Technology Program (ETP) which will develop the major technologies needed for SEI. In close coordination with other ongoing U.S. government research and development efforts, the ETP will provide in the near term clear demonstrations of potential exploration technologies, research results to support SEI architecture decisions, and a foundation of mature technology that is ready to be applied in the first round of SEI missions. In addition to the technology needed for the first round of SEI missions, the ETP will also put in place a foundation of research for longer-term technology needs-ultimately leading the human missions to Mars. The Space Exploration Initiative and the Exploration Technology Program will challenge the best and the brightest minds across government, industry and academia, inspiring students of all ages and making possible future terrestial applications of SEI technologies that may create whole new industries for the future. RP ALDRICH, A (reprint author), NASA HEADQUARTERS,NATL AERONAUT & SPACE ADM,OFF AERONAUT EXPLORAT & TECHNOL,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB PY 1992 VL 26 IS 2 BP 93 EP 103 DI 10.1016/0094-5765(92)90050-S PG 11 WC Engineering, Aerospace SC Engineering GA HZ228 UT WOS:A1992HZ22800003 ER PT J AU SPOTTS, JM SCHAEFER, WP MARDER, SR AF SPOTTS, JM SCHAEFER, WP MARDER, SR TI THE SYNTHESIS AND SPECTROSCOPIC PROPERTIES OF ORGANOMETALLIC CYANINE ANALOGS SO ADVANCED MATERIALS LA English DT Note ID MU-VINYLCARBYNE COMPLEXES; 2ND-HARMONIC GENERATION; OPTICAL NONLINEARITIES; METAL; CRYSTAL; ION AB Communication: Organometallic compounds with large transition dipole moments and small energy gaps are of potential interest as second- and third-order nonlinear optical materials. Organometallic anaologues of cyanines with electropositive metal centers as the end groups, in which the electronic coupling between the transition metal and the organic fragment is strong, should lead to improved extinction coefficients and great potential in nonlinear optics applications. C1 CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109. CALTECH,BECKMANN INST,CTR MOLEC MAT RESOURCE,PASADENA,CA 91125. RP SPOTTS, JM (reprint author), CALTECH,DIV CHEM & CHEM ENGN,PASADENA,CA 91109, USA. NR 39 TC 6 Z9 6 U1 0 U2 2 PU VCH PUBLISHERS INC PI DEERFIELD BEACH PA 303 NW 12TH AVE, DEERFIELD BEACH, FL 33442-1788 SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD FEB PY 1992 VL 4 IS 2 BP 100 EP 102 DI 10.1002/adma.19920040208 PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA HG051 UT WOS:A1992HG05100007 ER PT J AU MEHTA, UB AF MEHTA, UB TI NASP AND SDI SPEARHEAD CFD DEVELOPMENTS SO AEROSPACE AMERICA LA English DT Article RP MEHTA, UB (reprint author), NASA,AMES RES CTR,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 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD FEB PY 1992 VL 30 IS 2 BP 27 EP & PG 0 WC Engineering, Aerospace SC Engineering GA HD315 UT WOS:A1992HD31500007 ER PT J AU MOITRA, A AF MOITRA, A TI ENTHALPY DAMPING FOR HIGH MACH NUMBER EULER SOLUTIONS SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 21ST CONF ON FLUID DYNAMICS, PLASMA DYNAMICS, AND LASERS CY JUN 18-20, 1990 CL SEATTLE, WA SP AMER INST AERONAUT & ASTRONAUT AB An improvement on the enthalpy damping procedure currently in use in solving supersonic flowfields is described. A correction based on entropy values is shown to produce a very efficient scheme for simulation of high Mach number three-dimensional flows. Substantial improvements in convergence rates have been achieved by incorporating this enthalpy damping scheme in a finite-volume Runge-Kutta method for solving the Euler equations. Results obtained for blended wing-body geometries at high Mach numbers are presented. RP MOITRA, A (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 300 EP 301 DI 10.2514/3.10917 PG 2 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700002 ER PT J AU TAM, CKW NORUM, TD AF TAM, CKW NORUM, TD TI IMPINGEMENT TONES OF LARGE ASPECT RATIO SUPERSONIC RECTANGULAR JETS SO AIAA JOURNAL LA English DT Article ID DISCRETE AB When a supersonic rectangular jet of large aspect ratio is directed normal on a wall, numerous tones, sometimes as many as 20 or more, are generated. These tones are produced by feedback loops consisting of downstream propagating instability waves of the jet flow and upstream propagating acoustic waves from the wall to the nozzle lip. The frequency structure of those tones is analyzed. It is found that there are only two basic tones. The lower frequency basic tone is associated with a symmetric instability feedback mode of the jet. The higher frequency basic tone is associated with an antisymmetric instability feedback mode. All of the other tones are combination tones of the two basic frequencies and their harmonics. The feedback acoustic waves are investigated following a recent suggestion that they are formed by the upstream propagating neutral acoustic wave modes of the jet flow. These wave modes, just as the familiar Kelvin-Helmholtz instability waves, are supported by the mean flow of the jet and can be calculated in the same way. An analysis of these waves using a vortex sheet jet model is carried out. The calculated dispersion relations indicate that these waves can be divided into the symmetric and the antisymmetric families. Each family of waves consists of infinitely many modes. Each mode is, however, confined to a narrow band of frequencies. The frequencies of the first mode of each family are low enough to match those of the jet instability waves to form feedback loops. All of the recently measured basic tone frequencies are found to fall within (or very close to) the calculated allowable frequency bands over a wide range of jet operating conditions. This provides strong support for the validity of the most recently proposed feedback model. C1 NASA,LANGLEY RES CTR,DIV ACOUST & NOISE,HAMPTON,VA 23665. RP TAM, CKW (reprint author), FLORIDA STATE UNIV,DEPT MATH,TALLAHASSEE,FL 32306, USA. NR 11 TC 15 Z9 17 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 304 EP 311 DI 10.2514/3.10919 PG 8 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700004 ER PT J AU HARDIN, JC POPE, DS AF HARDIN, JC POPE, DS TI SOUND GENERATION BY A STENOSIS IN A PIPE SO AIAA JOURNAL LA English DT Article ID CROSS-SECTION; FLOW AB This paper presents a computational aeroacoustics study of sound generated by low Mach number flow through a closure (stenosis) in a circular pipe. The time-dependent incompressible flowfield in the pipe is first computed utilizing a vorticity/stream function formulation. The known velocity field is then utilized to determine the incompressible fluctuating pressure in the pipe. This hydrodynamic pressure field is then used to compute a hydrodynamic density perturbation to the constant incompressible density through the equation of state. Knowledge of this complete hydrodynamic field is then employed as the source of the resulting sound radiation. This tripartite technique allows separation of the compressible fluctuations from the purely hydrodynamic fluctuations. Results of the analysis are compared with experimental measurements of sound radiated by such a flow. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23665. RP HARDIN, JC (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 15 TC 10 Z9 12 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 312 EP 317 DI 10.2514/3.10920 PG 6 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700005 ER PT J AU PARROTT, TL ZORUMSKI, WE AF PARROTT, TL ZORUMSKI, WE TI SOUND-TRANSMISSION THROUGH A HIGH-TEMPERATURE ACOUSTIC PROBE TUBE SO AIAA JOURNAL LA English DT Article AB An investigation was conducted of acoustic transmission through a tube subjected to intense thermal gradients (50 K.mm-1) along its axis. The results are of interest in the interpretation of acoustic data from probe tube configurations designed to measure fluctuating pressures in high-temperature environments. The measured transfer function across a localized heated region in the tube was compared to a computed transfer function based on a theoretical analysis of propagation through strong temperature gradients. The heated region of the tube was produced by a specially designed concentric heater located at the midspan of the tube between two measurement microphones. Over the frequency range 0.4-6.0 kHz, generally good agreement was obtained between the measured and calculated attenuation across the heated region with some discrepancy occurring at the attenuation minima. Agreement between measured and calculated phase difference was excellent to within the measurement resolution. RP PARROTT, TL (reprint author), NASA,LANGLEY RES CTR,DIV ACOUST,APPL ACOUST BRANCH,HAMPTON,VA 23665, USA. NR 13 TC 13 Z9 13 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 318 EP 323 DI 10.2514/3.10921 PG 6 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700006 ER PT J AU SPEZIALE, CG ABID, R ANDERSON, EC AF SPEZIALE, CG ABID, R ANDERSON, EC TI CRITICAL-EVALUATION OF 2-EQUATION MODELS FOR NEAR-WALL TURBULENCE SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 21ST CONF ON FLUID DYNAMICS, PLASMA DYNAMICS, AND LASERS CY JUN 18-20, 1990 CL SEATTLE, WA SP AMER INST AERONAUT & ASTRONAUT ID REYNOLDS-NUMBER TURBULENCE; FLOWS; CHANNEL; STRESS; SCALE AB A variety of two-equation turbulence models-including several versions of the K-epsilon model as well as the K-omega model-are analyzed critically for near wall turbulent flows from a theoretical and computational standpoint. It is shown that the K-epsilon model has two major problems associated with it: the lack of natural boundary conditions for the dissipation rate and the appearance of higher-order correlations in the balance of terms for the dissipation rate at the wall. Insofar as the former problem is concerned, either physically inconsistent boundary conditions have been used or the boundary conditions for the dissipation rate have been tied to higher-order derivatives of the turbulent kinetic energy, which leads to numerical stiffness. The K-omega model can alleviate these problems since the asymptotic behavior of omega is known in more detail and since its near-wall balance involves only exact viscous terms. However, the modeled form of the omega equation used in the literature is incomplete: an exact viscous term is neglected, which causes the model to behave in an asymptotically inconsistent manner. By including this viscous term, and by introducing new wall damping functions with improved asymptotic behavior, a new K-tau model (where tau = 1/omega is the turbulent time scale) is developed. It is demonstrated that this new model yields improved predictions for turbulent boundary layers. C1 VIGYAN RES ASSOCIATES,HAMPTON,VA 23665. NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. RP SPEZIALE, CG (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 19 TC 77 Z9 80 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 324 EP 331 DI 10.2514/3.10922 PG 8 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700007 ER PT J AU JOSLIN, RD MORRIS, PJ AF JOSLIN, RD MORRIS, PJ TI EFFECT OF COMPLIANT WALLS ON SECONDARY INSTABILITIES IN BOUNDARY-LAYER-TRANSITION SO AIAA JOURNAL LA English DT Article ID HYDRODYNAMIC STABILITY; FLOW; SURFACES AB For aerodynamic and hydrodynamic vehicles, it is highly desirable to reduce drag and noise levels. A reduction in drag leads to fuel savings. In particular for submersible vehicles, a decrease in noise levels inhibits detection. A suggested means to obtain these reduction goals is by delaying the transition from laminar to turbulent flow in external boundary layers. For hydrodynamic applications, a passive device that shows promise for transition delays is the compliant coating. In previous studies with a simple mechanical model representing the compliant wall, coatings were found that provided transition delays as predicted from the semiempirical e(n) method. Those studies were concerned with the linear stage of transition where the instability of concern is referred to as the primary instability. For the flat-plate boundary layer, the Tollmien-Schlichting (TS) wave is the primary instability. In one of those studies, it was shown that three-dimensional (3-D) primary instabilities, or oblique waves, could dominate transition over the coatings considered. From the primary instability, the stretching and tilting of vorticity in the shear flow leads to a secondary instability mechanism. This has been theoretically described by Herbert based on Floquet theory. In the present study, Herbert's theory is used to predict the development of secondary instabilities over isotropic and nonisotropic compliant walls. Because oblique waves may be dominant over compliant walls, a secondary theory extention is made to allow for these 3-D primary instabilities. The effect of variations in primary amplitude, spanwise wavenumber, and Reynolds number on the secondary instabilities are examined. As in the rigid wall case, over compliant walls the subharmonic mode of secondary instability dominates for low-amplitude primary disturbances. Both isotropic and nonisotropic compliant walls lead to reduced secondary growth rates compared with the rigid wall results. For high frequencies, the nonisotropic wall suppresses the amplification of the secondary instabilities, while instabilities over the isotropic wall may grow with an explosive rate similar to the rigid wall results. For the more important lower frequencies, both isotropic and nonisotropic compliant walls suppress the amplification of secondary instabilities compared with rigid wall results. The twofold major discovery and demonstration of the present investigation are: 1) the use of passive devices, such as compliant walls, can lead to significant reductions in the secondary instability growth rates and amplification; 2) suppressing the primary growth rates and subsequent amplification enable delays in the growth of the explosive secondary instability mechanism. C1 PENN STATE UNIV,AEROSP ENGN,UNIV PK,PA 16802. RP JOSLIN, RD (reprint author), NASA,LANGLEY RES CTR,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665, USA. NR 28 TC 16 Z9 16 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 332 EP 339 DI 10.2514/3.10923 PG 8 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700008 ER PT J AU GARTENBERG, E JOHNSON, WG WRIGHT, RE CARRAWAY, DL JOHNSON, CB AF GARTENBERG, E JOHNSON, WG WRIGHT, RE CARRAWAY, DL JOHNSON, CB TI BOUNDARY-LAYER TRANSITION-DETECTION IN A CRYOGENIC WIND-TUNNEL USING INFRARED IMAGING SO AIAA JOURNAL LA English DT Article AB Cryogenic wind tunnels are currently the only option available to test models of medium to large transport air-planes at high Reynolds numbers identical to those encountered in flight. This matching in Reynolds numbers is required for reproducing the flow viscous effects, most notably the laminar to turbulent boundary-layer transition. Infrared imaging is particularly attractive for transition detection in cryogenic wind tunnels because it is nonintrusive, fast, and provides a global view of the boundary-layer status on the model. An experimental method using a commercial 8- to 12-mu infrared imaging system was developed for transition detection in cryogenic wind tunnels. So far, transition has been detected at temperatures down to 170 K. At this temperature, tunnels with a pressurization capability of only a few atmospheres can generate transonic flows at Reynolds numbers beyond 3 x 10(8) per meter. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP GARTENBERG, E (reprint author), OLD DOMINION UNIV,MECH ENGN & MECH,NORFOLK,VA 23529, USA. NR 4 TC 2 Z9 2 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 444 EP 446 DI 10.2514/3.10936 PG 3 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700021 ER PT J AU CURRY, JM JOHNSON, ER STARNES, JH AF CURRY, JM JOHNSON, ER STARNES, JH TI EFFECT OF DROPPED PLIES ON THE STRENGTH OF GRAPHITE-EPOXY LAMINATES SO AIAA JOURNAL LA English DT Article AB The reduction in the compressive and tensile strength of graphite-epoxy laminates with thickness discontinuities due to dropped plies was studied by experiment and analysis. The specimens were fabricated with all the dropped plies lumped together in the center of a 16-ply quasi-isotropic layup, such that one surface was flat and the slope of the opposite surface changed abruptly at the dropped ply location to accomodate the thickness change. Even though the thick and thin sections are symmetrically laminated, there exists bending-extension coupling due to the geometric eccentricity of the middle planes of the thick and thin sections. Results from tests on 37 specimens are reported that differed in the configuration of the dropped plies only. The axial strength of a laminate with dropped plies is less than its tensile strength. The reduction in axial strength is directly related to the axial stiffness change between the thick and thin sections. To examine the mechanism of failure, the three-dimensional state of stress in the dropped ply region was evaluated by the finite element method. A tensile interlaminar criterion predicted the correct location of failure, but underestimated the failure load, and therefore is a conservative analysis procedure for design. C1 VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. NASA,LANGLEY RES CTR,DIV STRUCT MECH,AIRCRAFT STRUCT BRANCH,HAMPTON,VA 23665. RP CURRY, JM (reprint author), ROHR IND INC,CHULA VISTA,CA 92012, USA. NR 12 TC 35 Z9 35 U1 2 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 449 EP 456 DI 10.2514/3.10938 PG 8 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700023 ER PT J AU HSU, CH CHEN, YM LIU, CH AF HSU, CH CHEN, YM LIU, CH TI PRECONDITIONED UPWIND METHODS TO SOLVE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS SO AIAA JOURNAL LA English DT Note C1 NASA,LANGLEY RES CTR,DIV FLUID MECH,THEORET FLOW PHYS BRANCH,HAMPTON,VA 23665. RP HSU, CH (reprint author), VIGYAN INC,HAMPTON,VA 23665, USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 550 EP 552 DI 10.2514/3.10951 PG 3 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700036 ER PT J AU THANGAM, S ABID, R SPEZIALE, CG AF THANGAM, S ABID, R SPEZIALE, CG TI APPLICATION OF A NEW K-TAU MODEL TO NEAR WALL TURBULENT FLOWS SO AIAA JOURNAL LA English DT Note ID ADVERSE PRESSURE-GRADIENT; LAYER C1 STEVENS INST TECHNOL LIB,DEPT MECH ENGN,HOBOKEN,NJ 07030. RP THANGAM, S (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665, USA. NR 12 TC 7 Z9 7 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1992 VL 30 IS 2 BP 552 EP 554 DI 10.2514/3.10952 PG 3 WC Engineering, Aerospace SC Engineering GA HE967 UT WOS:A1992HE96700037 ER PT J AU WADE, CE TILLMAN, FJ LOVEDAY, JA BLACKMON, A POTANKO, E HUNT, MM HANNON, JP AF WADE, CE TILLMAN, FJ LOVEDAY, JA BLACKMON, A POTANKO, E HUNT, MM HANNON, JP TI EFFECT OF DEHYDRATION ON CARDIOVASCULAR-RESPONSES AND ELECTROLYTES AFTER HYPERTONIC SALINE DEXTRAN TREATMENT FOR MODERATE HEMORRHAGE SO ANNALS OF EMERGENCY MEDICINE LA English DT Article DE FLUID RESUSCITATION; HYPERTONIC SALINE DEXTRAN; HYPOTENSION AB Study objective: To determine if hypertonic saline/dextran (HSD) is effective in treating hemorrhage in the presence of dehydration. Design: After surgical preparation, swine were euhydrated or dehydrate for 24 or 48 hours. Animals were bled 25 mL/kg over 60 minutes and treated with HSD. Setting: Laboratory. Participants: Seventeen immature Yorkshire pigs. Interventions: 4 ml/kg HSD (7.5% NaCl in 6% dextran-70) administered over one minute. Measurements and main results: All euhydrated animals survived; 100% of the pigs survived 180 minutes after treatment. Two animals dehydrated for 24 hours and three animals dehydrated for 48 hours died within three hours of HSD treatment. In all groups, plasma potassium was reduced significantly and equally; cardiac output was increased; mean arterial pressure rose rapidly within first five minutes, but was sustained only in euhydrated animals; hematocrit, hemoglobin, and plasma total protein levels were reduced; and plasma glucose increased with persistent between-group differences. Results: HSD immediately rectified the decreases in mean arterial pressure and cardiac output incurred during hemorrhage; over time, however, the improvement in pressure was not sustained in dehydrated pigs. Parallel increases in plasma osmolality and sodium concentrations were offset by the initial group differences resulting from dehydration. Conclusion: Dehydration does not compromise the efficacy of IISD as a resuscitation treatment for hemorrhagic shock. RP WADE, CE (reprint author), NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035, USA. NR 0 TC 23 Z9 27 U1 0 U2 0 PU MOSBY-YEAR BOOK INC PI ST LOUIS PA 11830 WESTLINE INDUSTRIAL DR, ST LOUIS, MO 63146-3318 SN 0196-0644 J9 ANN EMERG MED JI Ann. Emerg. Med. PD FEB PY 1992 VL 21 IS 2 BP 113 EP 119 DI 10.1016/S0196-0644(05)80143-X PG 7 WC Emergency Medicine SC Emergency Medicine GA HB580 UT WOS:A1992HB58000001 PM 1371210 ER PT J AU KARAGEORGHIS, A PHILLIPS, TN AF KARAGEORGHIS, A PHILLIPS, TN TI ON THE COEFFICIENTS OF DIFFERENTIATED EXPANSIONS OF ULTRASPHERICAL POLYNOMIALS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID MODELING VISCOELASTIC FLOWS; BOUNDARY-VALUE PROBLEM AB A formula expressing the coefficients of an expansion of ultraspherical polynomials which has been differentiated an arbitrary number of times in terms of the coefficients of the original expansion is proved. The particular examples of Chebyshev and Legendre polynomials are considered. C1 SO METHODIST UNIV,DEPT MATH,DALLAS,TX 75275. UNIV COLL WALES,DEPT MATH,ABERYSTWYTH SY23 3BZ,WALES. NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. OI Phillips, Timothy/0000-0001-6455-1205 NR 10 TC 13 Z9 13 U1 0 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 FEB PY 1992 VL 9 IS 2 BP 133 EP 141 DI 10.1016/0168-9274(92)90010-B PG 9 WC Mathematics, Applied SC Mathematics GA HD722 UT WOS:A1992HD72200003 ER PT J AU MASSIE, NA OSTER, Y POE, G SEPPALA, L SHAO, M AF MASSIE, NA OSTER, Y POE, G SEPPALA, L SHAO, M TI LOW-COST, HIGH-RESOLUTION, SINGLE-STRUCTURE ARRAY TELESCOPES FOR IMAGING OF LOW-EARTH-ORBIT SATELLITES SO APPLIED OPTICS LA English DT Article ID STELLAR SPECKLE INTERFEROMETRY AB Telescopes that are designed for the unconventional imaging of near-Earth satellites must follow unique design rules. The costs must be reduced substantially over those of the conventional telescope designs, and the design must accommodate a technique to circumvent atmospheric distortion of the image. Apertures of 12 m and more along with altitude-altitude mounts that provide high tracking rates are required. A novel design for such a telescope, optimized for speckle imaging, has been generated. Its mount closely resembles a radar mount, and it does not use the conventional dome. Costs for this design are projected to be considerably lower than those for the conventional designs. Results of a design study are presented with details of the electro-optical and optical designs. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. DAEDALUS,DEL MAR,CA 92014. RP MASSIE, NA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 1 PY 1992 VL 31 IS 4 BP 447 EP 456 PG 10 WC Optics SC Optics GA HB566 UT WOS:A1992HB56600015 PM 20720634 ER PT J AU HANNAN, PG AF HANNAN, PG TI GENERAL-ANALYSIS OF 2-MIRROR RELAY SYSTEMS SO APPLIED OPTICS LA English DT Article DE ABERRATIONS; GEOMETRICAL OPTICS; MIRRORS; OPTICAL DESIGN; OPTICAL SYSTEMS AB The general two-mirror system used at finite conjugates is examined here. Relations for first-order geometric properties and third-order aberrations are given in terms of five design parameters: object distance, image distance, exit pupil size, and the two mirror magnifications. The conditions for aplanatic solutions are derived for conic mirrors. The curvatures of the astigmatic image surfaces are given, and the condition for anastigmatic solutions is derived. The relations are applied to infinite conjugate systems and spherical mirror systems as special cases. RP HANNAN, PG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,OPT BRANCH,GREENBELT,MD 20771, USA. NR 10 TC 10 Z9 11 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 1 PY 1992 VL 31 IS 4 BP 513 EP 518 PG 6 WC Optics SC Optics GA HB566 UT WOS:A1992HB56600025 PM 20720644 ER PT J AU KURTZ, J AF KURTZ, J TI LABORATORY SPECTRA OF GAS-PHASE CORONENE AT ELEVATED-TEMPERATURES SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE INFRARED SPECTROSCOPY; INTERSTELLAR MEDIUM, MOLECULES; UNIDENTIFIED INFRARED BANDS; POLYCYCLIC AROMATIC HYDROCARBONS; CORONENE (C24H12) ID UNIDENTIFIED INFRARED BANDS; MOLECULES AB Gas-phase infrared spectra of coronene from 4000 to 400 cm-1 are presented in emission and absorption at temperatures from 350 to 450-degrees-C. Peak positions are compared to KBr pellet data and to a previously published neon matrix-isolated coronene spectrum. Relative feature strengths are analyzed and used to estimate a temperature of interstellar PAHs assuming thermal emission. C1 NASA, GODDARD SPACE FLIGHT CTR, NATL ACAD SCI, NATL RES COUNCIL RES ASSOC, GREENBELT, MD 20771 USA. NR 5 TC 25 Z9 25 U1 0 U2 2 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 1992 VL 255 IS 1-2 BP L1 EP L4 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HE989 UT WOS:A1992HE98900001 ER PT J AU SCHNEID, EJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K ROTHERMEL, H SOMMER, M SREEKUMAR, P THOMPSON, DJ AF SCHNEID, EJ BERTSCH, DL FICHTEL, CE HARTMAN, RC HUNTER, SD KANBACH, G KNIFFEN, DA KWOK, PW LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL PINKAU, K ROTHERMEL, H SOMMER, M SREEKUMAR, P THOMPSON, DJ TI EGRET DETECTION OF HIGH-ENERGY GAMMA-RAYS FROM THE GAMMA-RAY BURST OF 3 MAY 1991 SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE GAMMA-RAYS; BURSTS ID 1979 MARCH 5; TRANSIENT; LOCATION AB On May 3, 1991, the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory detected a gamma-ray burst both in the energy measurement subsystem and independently in the spark chamber assembly. Six individual photons were detected in the spark chamber, allowing a determination of the burst arrival direction which was l(II) = 171.9-degrees +/- 1.3-degrees, b(II) = 5.3-degrees +/- 1.1-degrees. Three energy spectra were measured from 1 to 200 MeV; they were measured during the first second after the BATSE trigger, the next two seconds and the subsequent four seconds. The first two spectra exhibit a similar differential spectra index of about -2.2 with no apparent high-energy cut-off. By the time of the third spectrum, and additional soft component is evident. C1 NASA, GODDARD SPACE FLIGHT CTR, NATL ACAD SCI, GREENBELT, MD 20771 USA. STANFORD UNIV, HANSEN EXPTL PHYS LAB, STANFORD, CA 94305 USA. NASA, GODDARD SPACE FLIGHT CTR, COMP SCI CORP, GRO SCI SUPPORT CTR, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. MAX PLANCK INST EXTRATERRESTR PHYS, W-8046 GARCHING, GERMANY. HAMPDEN SYDNEY COLL, HAMPDEN SYDNEY, VA 23943 USA. RP SCHNEID, EJ (reprint author), GRUMMAN AEROSP CORP, MAIL STOP A01-26, BETHPAGE, NY 11714 USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 10 TC 94 Z9 94 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 1992 VL 255 IS 1-2 BP L13 EP L16 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HE989 UT WOS:A1992HE98900004 ER PT J AU SAGDEYEV, RZ KERZHANOVITCH, VV KOGAN, LR KOSTENKO, VI LINKIN, VM MATVEYENKO, LI NAZIROV, RR POGREBENKO, SV STRUCKOV, IA PRESTON, RA PURCEL, J HILDEBRAND, CE GRISHMANOVSKIY, VA KOZLOV, AN MOLOTOV, EP BLAMONT, JE BOLOH, L LAURANS, G KAUFMANN, P GALT, J BIRAUD, F BOISCHOT, A ORTEGAMOLINA, A ROSOLEN, C PETIT, G MEZGER, PG SCHWARTZ, R RONNANG, BO SPENCER, RE NICOLSON, G ROGERS, AEE COHEN, MH MARTIROSYAN, RM MOISEYEV, IG JATSKIV, JS AF SAGDEYEV, RZ KERZHANOVITCH, VV KOGAN, LR KOSTENKO, VI LINKIN, VM MATVEYENKO, LI NAZIROV, RR POGREBENKO, SV STRUCKOV, IA PRESTON, RA PURCEL, J HILDEBRAND, CE GRISHMANOVSKIY, VA KOZLOV, AN MOLOTOV, EP BLAMONT, JE BOLOH, L LAURANS, G KAUFMANN, P GALT, J BIRAUD, F BOISCHOT, A ORTEGAMOLINA, A ROSOLEN, C PETIT, G MEZGER, PG SCHWARTZ, R RONNANG, BO SPENCER, RE NICOLSON, G ROGERS, AEE COHEN, MH MARTIROSYAN, RM MOISEYEV, IG JATSKIV, JS TI DIFFERENTIAL VLBI MEASUREMENTS OF THE VENUS ATMOSPHERE DYNAMICS BY BALLOONS - VEGA PROJECT SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE PLANETOLOGY; VENUS ATMOSPHERE; VLBI ID 1ST STAGE; MISSIONS AB Results are reported of the measurement of balloon motion in the upper layers of the Venus atmosphere. The measurement of the balloon trajectories was carried out by differential very-long-baseline interferometry (VLBI) observations of the balloons relative to the fly-by spacecrafts (VEGA-1 and VEGA-2). Balloon-2, launched in the southern hemisphere of the planet led to the discovery of gas motion with average velocities of 65.3 m s-1 and 3.4 m s-1 in longitude and latitude, respectively. Balloon-1, launched in the northern hemisphere, showed that gas motions occur with an average velocity of 68.7 m s-1 in the longitudinal direction, but no wind was detected in the latitudinal direction. Pendulum motion of the balloon baskets with a period of 7.4 s was detected on many occasions. This occurred 10 times more frequently in the southern hemisphere than in the northern one. The nature of these phenomena is discussed. C1 MAX PLANCK INST RADIOASTRON, HUGEL 69, W-5300 BONN 1, GERMANY. MOSCOW SPACE RES INST, MOSCOW 117810, USSR. MOSCOW SPACE EQUIPMENT DESIGN INST, MOSCOW 111250, USSR. DOMINION RADIO ASTROPHYS OBSERV, PENTICTON V2A 6K3, BC, CANADA. OBSERV PARIS, F-92190 MEUDON, FRANCE. INST GEOG NATL, F-94160 ST MANDE, FRANCE. ONSALA SPACE OBSERV, S-43900 ONSALA, SWEDEN. NUFFIELD RADIO ASTRON OBSERV LABS, MACCLESFIELD SK11 9DL, CHESHIRE, ENGLAND. HARTEBEESTHOEK RADIO OBSERV, KRUGERSDORF 1740, SOUTH AFRICA. MIT, HAYSTACK OBSERV, WESTFORD, MA 01886 USA. CRIMEAN ASTROPHYS OBSERV, NAUCHNYI 334413, UKRAINE, USSR. MAIN ASTRON OBSERV UKRAINE, KIEV 252127, UKRAINE, USSR. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. CTR NATL ETUD SPATIALES, F-75039 PARIS 01, FRANCE. INST PESQUISAS ESPACIALS, BR-12200 SAO JOSE CAMPOS, SP, BRAZIL. CALTECH, OWENS VALLEY RADIO OBSERV, PASADENA, CA 91125 USA. ASCHTARAK RADIOPHYS & ELECTR INST, ASCHTARAK 1, ARMENIA, USSR. RI Kostenko, Vladimir/M-3811-2015 NR 12 TC 21 Z9 22 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 1992 VL 254 IS 1-2 BP 387 EP 392 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HC817 UT WOS:A1992HC81700056 ER PT J AU BACKMAN, DE GILLETT, FC WITTEBORN, FC AF BACKMAN, DE GILLETT, FC WITTEBORN, FC TI INFRARED OBSERVATIONS AND THERMAL MODELS OF THE BETA-PICTORIS DISK SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION, ACCRETION DISKS; DUST, EXTINCTION; RADIATION MECHANISMS, THERMAL; STARS, INDIVIDUAL (BETA-PICTORIS) ID CIRCUMSTELLAR DISK; ABSOLUTE CALIBRATION; STARS; IRAS; VEGA; PHOTOMETRY; PLANETS; 10-MU-M; 20-MU-M; SYSTEM AB Photometry at lambda = 3.5-20-mu-m in 4" and 8" apertures was obtained to measure the flux from the central portion of the beta Pic disk. The 10.1 and 20-mu-m measurements show an excess (relative to the photosphere) which is extended, with significant flux located in the annulus between 4" and 8" diameter centered on the star. Disk models have been calculated to reproduce the ground-based IR data, IRAS fluxes, IRAS 60-mu-m scan profile widths, and optical scattered light distribution. The model results imply: (1) the color temperature and angular scale of the disk are not consistent with emission from large ("blackbody") particles: most of the thermal emission originates from particles which are inefficient radiators, with sizes near 1-mu-m; (2) a simple disk with a single power law spatial distribution is inconsistent with the combined optical and infrared data: models are presented with two structural components, r > 80 AU and r < 80, which are better matches to the available observations; (3) the inner disk component represents a gross deficit of material relative to an inward extrapolation of the outer component; (4) the temperature of typically sized grains at the boundary between the outer and the inner components is in the range 90-140 K, corresponding to the temperature of transition from slow to rapid sublimation of water ice: sublimation would proceed more rapidly than other destruction mechanisms for small ice grains inside the boundary and could be responsible for the relative depletion of grains in the inner disk component; (5) an albedo of approximately 0.35 is deduced for the particles in the outer component; (6) most of the material in the inner component is at temperatures where sublimation of small water ice grains would occur so rapidly that predominance of refractory grains is indicated; (7) the 10-mu-m observations appear to require that the inner component extends inward only to a limit between about 1 and 30 AU from the star, leaving an innermost void. C1 NATL OPT ASTRON OBSERV,KITT PEAK NATL OBSERV,TUCSON,AZ 85726. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 36 TC 80 Z9 80 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 1992 VL 385 IS 2 BP 670 EP 679 DI 10.1086/170973 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HB576 UT WOS:A1992HB57600025 ER PT J AU HODGES, RE AF HODGES, RE TI GIVE OS/2 A CHANCE SO BYTE LA English DT Letter RP HODGES, RE (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BYTE PUBL INC PI PETERBOROUGH PA 70 MAIN ST, PETERBOROUGH, NH 03458 SN 0360-5280 J9 BYTE JI Byte PD FEB PY 1992 VL 17 IS 2 BP 14 EP & PG 0 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA GZ885 UT WOS:A1992GZ88500006 ER PT J AU CHUNG, GY MCCOY, BJ SMITH, JM CAGLIOSTRO, DE AF CHUNG, GY MCCOY, BJ SMITH, JM CAGLIOSTRO, DE TI CHEMICAL VAPOR INFILTRATION - MODELING SOLID MATRIX DEPOSITION FOR CERAMIC COMPOSITES REINFORCED WITH LAYERED WOVEN FABRICS SO CHEMICAL ENGINEERING SCIENCE LA English DT Article AB A model is developed for chemical vapor infiltration in a sample of overlapping, woven plies. The holes through each ply, formed by the interweaving of filamentous tows, are considered to be staggered maximally for the overlapping plies. The results are compared with another bounding case, the aligned-hole model studied previously. The staggered-hole model predicts concentration profiles, deposition amounts, porosities, and changes of dimensions with time. The model also explains the effects of diffusion, rate of deposition, and spatial distribution of filaments in the woven fabric. Staggering the holes leads to somewhat less uniform deposition in the holes between tows and in the spaces between plies. C1 UNIV CALIF DAVIS,DEPT CHEM ENGN,DAVIS,CA 95616. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 17 TC 19 Z9 19 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD FEB PY 1992 VL 47 IS 2 BP 311 EP 323 DI 10.1016/0009-2509(92)80022-5 PG 13 WC Engineering, Chemical SC Engineering GA GZ187 UT WOS:A1992GZ18700003 ER PT J AU CHEN, YM CINTRON, NM WHITSON, PA AF CHEN, YM CINTRON, NM WHITSON, PA TI LONG-TERM STORAGE OF SALIVARY CORTISOL SAMPLES AT ROOM-TEMPERATURE SO CLINICAL CHEMISTRY LA English DT Note ID PLASMA C1 NASA,LYNDON B JOHNSON SPACE CTR,RES BRANCH,HOUSTON,TX 77058. KRUG LIFE SCI,HOUSTON,TX 77058. RP CHEN, YM (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT,MAIL CODE SD4,HOUSTON,TX 77058, USA. NR 4 TC 40 Z9 43 U1 0 U2 1 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD FEB PY 1992 VL 38 IS 2 BP 304 EP 304 PG 1 WC Medical Laboratory Technology SC Medical Laboratory Technology GA HF057 UT WOS:A1992HF05700023 PM 1541015 ER PT J AU ALTMAN, J CHAN, J GRYMES, RA BAUER, EA AF ALTMAN, J CHAN, J GRYMES, RA BAUER, EA TI COLLAGENASE EXPRESSION IN PROGERIOD FIBROBLASTS - HYDROCORTISONE SUPPRESSION SO CLINICAL RESEARCH LA English DT Meeting Abstract C1 STANFORD UNIV,MED CTR,SCH MED,DEPT DERMATOL,STANFORD,CA 94305. NASA,AMES RES CTR,DIV LIFE SCI,MOFFETT FIELD,CA 94035. 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 1992 VL 40 IS 1 BP A73 EP A73 PG 1 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA HA103 UT WOS:A1992HA10300398 ER PT J AU CARPENTER, A AF CARPENTER, A TI NEW ASPECTS RELATING TO THE BEHAVIOR OF COMPOSITES IN SPACE SO COMPOSITES ENGINEERING LA English DT Article AB This describes some of the specialized testing being performed at the Jet Propulsion Laboratory specifically for the WideField Planetary Camera II (WFPC II) program (as the operational heart of the Hubble Telescope) toward screening polymeric materials as regards outgassing behaviour. The WFPC II is designed to replace WFPC I (presently in orbit) and to correct the Hubble's present optical difficulties. In addition, the WFPC II is being fabricated as an ultraviolet-imaging science instrument. As such, this poses unique, stringent cleanliness requirements and very low levels of contamination-allowables. These cleanliness requirements thus become absolutely crucial to mission performance. Hopefully, this testing will generate additional interest and continued research activity in further elucidating the chemistry involved in outgassing and contamination behaviour. RP CARPENTER, A (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, 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 0961-9526 J9 COMPOS ENG JI Compos. Eng. PD FEB PY 1992 VL 2 IS 2 BP 137 EP 147 DI 10.1016/0961-9526(92)90051-7 PG 11 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA HK093 UT WOS:A1992HK09300005 ER PT J AU HOSSAIN, M MATTHAEUS, WH GHOSH, S AF HOSSAIN, M MATTHAEUS, WH GHOSH, S TI ON COMPUTING HIGH-ORDER GALERKIN PRODUCTS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article AB Aliasing errors are known to cause serious problems in spectral method simulation of fluids, magnetohydrodynamics, and other nonlinear problems. Methods for computing aliasing error free products of two functions are well known. Here we present an extension of these methods to products of more than two functions. This solves one problem in implementing the Galerkin spectral method for compressible flows. C1 NASA,GODDARD SPACE FLIGHT CTR,CODE 692,GREENBELT,MD 20771. RP HOSSAIN, M (reprint author), UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716, USA. RI Hossain, Murshed/A-9612-2008 OI Hossain, Murshed/0000-0001-7996-9233 NR 6 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1992 VL 69 IS 1 BP 1 EP 6 DI 10.1016/0010-4655(92)90123-G PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA HF682 UT WOS:A1992HF68200001 ER PT J AU SHIH, CY NYQUIST, LE BANSAL, BM WIESMANN, H AF SHIH, CY NYQUIST, LE BANSAL, BM WIESMANN, H TI RB-SR AND SM-ND CHRONOLOGY OF AN APOLLO-17 KREEP BASALT SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article ID PRECISE DETERMINATION; ISOTOPIC EVOLUTION; AGE; CHONDRITES; CLAST; CRUST; CHEMISTRY; BOULDER-1; STATION-2; EUCRITE AB Sm-Nd and Rb-Sr mineral isochrons were determined for an Apollo 17 KREEP (pigeonite) basalt clast (,543) from breccia 72275 collected from Boulder 1, Station 2 in the Valley of Taurus-Littrow. Sm-Nd analyses of the basalt yield a precise mineral isochron age of 4.08 +/- 0.07 Ga for lambda(Sm-147) = 0.00654 Ga - 1. The Rb-Sr mineral isochron age of 4.13 +/- 0.08 Ga for lambda(RB-87) = 0.0139 Ga-1 is concordant with the Sm-Nd age. However, the Rb-Sr isotopic system has been slightly disturbed, probably by the Serenitatis impact event approximately 3.95 Ga ago. The Sm-Nd age is interpreted as the crystallization age of this Apollo 17 KREEP basalt. Ages and initial Sr-87/Sr-86 and epsilon(Nd) values for this basalt and Apollo 14 and 15 KREEP basalts suggest that these two types of KREEP basalts could be produced from sources having similar Rb/Sr and Sm/Nd ratios. These new age data suggest that KREEP basaltic volcanism started approximately 200 Ma earlier than the approximately 3.85 Ga age generally accepted from studies of Apollo 15 pristine KREEP basalts. Apollo 17 KREEP basalts probably pre-date the Serenitatis impact, strongly indicating that not all KREEP basaltic volcanism was necessarily related to basin-forming impacts. The younger Apollo 15 and 14 KREEP basalts probably are related to the Imbrium impact, however. The ages and epsilon(Nd) values for KREEP basalts, granites, troctolites and norites from a variety of lunar sites form a linear array corresponding to source(s) with Sm/Nd lower by approximately 15% than the chondritic value (slightly enriched in LREE). suggesting that these rocks could be genetically related. Formation of a common Sm-Nd isotopic growth curve by these data is most easily explained by an early moon-wide differentiation accompanying the formation and subsequent solidification of a global magma ocean. C1 NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. RP LOCKHEED ENGN & SCI CO, MAIL CODE C-23, 2400 NASA RD 1, HOUSTON, TX 77258 USA. NR 62 TC 25 Z9 25 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X EI 1385-013X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD FEB PY 1992 VL 108 IS 4 BP 203 EP 215 DI 10.1016/0012-821X(92)90023-O PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA HJ288 UT WOS:A1992HJ28800004 ER PT J AU HOFF, RM MUIR, DCG GRIFT, NP AF HOFF, RM MUIR, DCG GRIFT, NP TI ANNUAL CYCLE OF POLYCHLORINATED-BIPHENYLS AND ORGANOHALOGEN PESTICIDES IN AIR IN SOUTHERN ONTARIO .1. AIR CONCENTRATION DATA SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID LONG-RANGE TRANSPORT; MOLECULAR-WEIGHT ORGANOCHLORINES; HIGH-VOLUME COLLECTION; EASTERN NORTH-AMERICA; HENRY LAW CONSTANTS; CHLORINATED HYDROCARBONS; ATMOSPHERIC TRANSPORT; ORGANIC-COMPOUNDS; AROMATIC-HYDROCARBONS; POLYURETHANE FOAM AB From July 1988 to September 1989, 143 air samples, obtained at Egbert, ON, Canada, were analyzed for vapor-phase polychlorinated biphenyls (PCBs) and organohalogen pesticides. This data set is believed to be the first high temporal resolution PCB data set obtained over an annual cycle in North America and has obvious use for determining processes of deposition, transport, and atmospheric transformation of these important chemicals. Concentrations of the sum of 91 PCB congeners (SIGMA-PCB) of IUPAC No. 16 or higher ranged from a subpicogram per cubic meter detection level to over 2 ng m-3. Monthly averages of SIGMA-PCB ranged from 55 to 823 pg m-3. Organochlorine pesticide maximum (mean) concentrations were as follows: for SIGMA-HCH, 1 ng m-3 (20 pg m 3); for SIGMA-CHLOR, 430 (81) pg m 3; for PCCs, 580 (26) pg m-3; for SIGMA-DDT, 560 (90) pg m-3; for dieldrin, 210 (46) pg m-3. Higher concentrations of the locally and regionally used pesticides trifluralin [3.4 ng m-3 (270 pg m 3)] and endosulfan [3.7 ng m-3 (346 pg m 3)] were found. Some of these values were actually higher than reported in other studies since the 1970s. The ratio alpha-HCH/gamma-HCH has a well-defined annual cycle peaking in winter at approximately 7 and minimizing in summer at approximately 1. The concentrations of these species suggest a Lorentzian form for the annual cycle of these chemicals. SIGMA-PCBs have a minimum in this function of 55 pg m-3 and a maximum amplitude 14 times this minimum, occurring in late July and with a half-width of 0.67 month. SIGMA-DDT has a minimum of 11 pg m-3 with an amplitude of 20 times the minimum value, again peaking in late July but with a half-width of 1.7 month. This function is readily programmable into models which make use of the air concentration data to determine deposition (both wet and dry). C1 FISHERIES & OCEANS CANADA,INST FRESHWATER,WINNIPEG R3T 2N6,MANITOBA,CANADA. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP HOFF, RM (reprint author), ATMOSPHER ENVIRONM SERV,RURAL ROUTE 1,EGBERT L0L 1L0,ONTARIO,CANADA. NR 68 TC 232 Z9 237 U1 2 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB PY 1992 VL 26 IS 2 BP 266 EP 275 DI 10.1021/es00026a005 PG 10 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA HB871 UT WOS:A1992HB87100012 ER PT J AU BEEBE, RF BARNET, C SADA, PV MURRELL, AS AF BEEBE, RF BARNET, C SADA, PV MURRELL, AS TI THE ONSET AND GROWTH OF THE 1990 EQUATORIAL DISTURBANCE ON SATURN SO ICARUS LA English DT Article ID VOYAGER C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BEEBE, RF (reprint author), NEW MEXICO STATE UNIV,DEPT ASTRON,POB 30001,LAS CRUCES,NM 88003, USA. RI Barnet, Christopher/F-5573-2010 NR 28 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 1992 VL 95 IS 2 BP 163 EP 172 DI 10.1016/0019-1035(92)90035-6 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK989 UT WOS:A1992HK98900001 ER PT J AU BOSTON, PJ IVANOV, MV MCKAY, CP AF BOSTON, PJ IVANOV, MV MCKAY, CP TI ON THE POSSIBILITY OF CHEMOSYNTHETIC ECOSYSTEMS IN SUBSURFACE HABITATS ON MARS SO ICARUS LA English DT Article ID GROUND ICE INTERACTIONS; VALLES-MARINERIS; PYRITE FORMATION; EVOLUTION; LIFE; ORIGIN; ATMOSPHERE; DEPOSITS; ARCHAEBACTERIA; ENVIRONMENT C1 ACAD SCI USSR,INST MICROBIOL,MOSCOW 117811,USSR. NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RP BOSTON, PJ (reprint author), COMPLEX SYST RES,POB 11320,BOULDER,CO 80301, USA. NR 74 TC 186 Z9 191 U1 9 U2 40 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 1992 VL 95 IS 2 BP 300 EP 308 DI 10.1016/0019-1035(92)90045-9 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK989 UT WOS:A1992HK98900011 PM 11539823 ER PT J AU REUTER, DC HOBAN, S MUMMA, MJ AF REUTER, DC HOBAN, S MUMMA, MJ TI AN INFRARED SEARCH FOR FORMALDEHYDE IN SEVERAL COMETS SO ICARUS LA English DT Note ID HALLEY RP REUTER, DC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,PLANETARY SYST BRANCH,CODE 693,GREENBELT,MD 20071, USA. RI mumma, michael/I-2764-2013 NR 14 TC 12 Z9 12 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 1992 VL 95 IS 2 BP 329 EP 332 DI 10.1016/0019-1035(92)90049-D PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA HK989 UT WOS:A1992HK98900015 ER PT J AU MURTHY, KMS NUSPL, PP RAFFERTY, W KATO, S SMITH, GK AF MURTHY, KMS NUSPL, PP RAFFERTY, W KATO, S SMITH, GK TI ADVANCES IN SATELLITE-COMMUNICATIONS NETWORKING AND APPLICATIONS SO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS LA English DT Editorial Material C1 INTELSAT, WASHINGTON, DC 20008 USA. CALTECH, JET PROP LAB, NASA, SATELLITE COMMUN PROGRAM, PASADENA, CA 91109 USA. NIPPON TELEGRAPH & TEL PUBL CORP, YOKOSUKA ELECT COMMUN LABS, RADIO COMMUN SYST LABS, YOKOSUKA, KANAGAWA 23803, JAPAN. INMARSAT, LONDON NW1 2EQ, ENGLAND. UNIV OTTAWA, ELECT ENGN, OTTAWA K1N 6N5, ONTARIO, CANADA. RP MURTHY, KMS (reprint author), TELESAT CANADA, APPLICAT RES & DEV SECT, 1601 TELESAT COURT, GLOUCESTER K1B 5P4, ONTARIO, CANADA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0733-8716 EI 1558-0008 J9 IEEE J SEL AREA COMM JI IEEE J. Sel. Areas Commun. PD FEB PY 1992 VL 10 IS 2 BP 305 EP 308 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HE822 UT WOS:A1992HE82200001 ER PT J AU LEVITT, BK AF LEVITT, BK TI RAIN COMPENSATION ALGORITHM FOR ACTS MOBILE TERMINAL SO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS LA English DT Article AB Having successfully completed the L-band mobile satellite experiment (MSAT-X), the Jet Propulsion Laboratory is now developing a system to demonstrate Ka-band land-mobile satellite communication technologies in conjunction with NASA's Advanced Communication Technology Satellite (ACTS). The experiment will involve two-way communications between a fixed terminal (FT) in Cleveland and a van-mounted ACTS mobile terminal (AMT) using the satellite in a bent-pipe (30 GHz uplink, 20 GHz downlink) relay mode. Although AMT will initially be located in the greater Los Angeles area, it is designed to operate satisfactorily anywhere within the contiguous United States (CONUS). To a far greater extent than MSAT-X, AMT must cope with the impact of propagation effects on link performance, with particular concern for rain attenuation. This paper describes a novel technique for ameliorating the effects of rain fading on AMT communications by varying the data rate in response to real-time power measurements of the pilot signal received by AMT and the ACTS beacons received by the FT. The AMT rain-compensation algorithm (RCA) employs both fade and fade-rate statistics to determine the appropriate data rate, and uses empirical frequency-scaling formulas, described herein, to accommodate any differences between the measured fading signal and the communications link. A worst-month rain attenuation model is used to argue that the RCA will boost the AMT-ACTS-FT link availability, defined as the percentage of time that the performance margin exceeds 3 dB, from 97.2% to 99.7% when the AMT is in Los Angeles, and from 90.5% to 98.1% in Portland, ME where rain events are more of a factor. RP LEVITT, BK (reprint author), CALTECH,JET PROP LAB,COMMUN RES SECT,PASADENA,CA 91109, USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0733-8716 J9 IEEE J SEL AREA COMM JI IEEE J. Sel. Areas Commun. PD FEB PY 1992 VL 10 IS 2 BP 358 EP 363 DI 10.1109/49.126987 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA HE822 UT WOS:A1992HE82200007 ER EF