FN Thomson Reuters Web of Science™ VR 1.0 PT J AU BALLESTER, JL SHI, Y DWEK, E AF BALLESTER, JL SHI, Y DWEK, E TI PHOTOELECTRON YIELD OF SILICATE AND GRAPHITE GRAINS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID INTERSTELLAR; GAS AB The photoelectric yields of small silicate and graphite grains are calculated as a function of incident photon wavelength for the purpose of modeling interstellar grains. The large surface-to-volume ratio of a small grain is expected to result in an increased photoelectric yield when compared with a bulk sample of the same material. The ratio of grain yield to bulk yield is calculated from the Mie solution for the fields inside a spherical particle and from assumptions regarding the electron emission process, yields are calculated from published bulk yields for wavelengths of 900-1500 Angstrom. for grain radii of 100 and 1000 Angstrom. These results should be useful for future investigations of photoelectric emission from interstellar grains. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP BALLESTER, JL (reprint author), EMPORIA STATE UNIV,DEPT PHYS,EMPORIA,KS 66801, USA. RI Ballester, Jose /A-2637-2011 OI Ballester, Jose /0000-0001-8921-9225 NR 8 TC 3 Z9 3 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 JUL PY 1995 VL 12 IS 7 BP 1211 EP 1214 DI 10.1364/JOSAB.12.001211 PG 4 WC Optics SC Optics GA RH119 UT WOS:A1995RH11900004 ER PT J AU DELACRUZ, SC MACCORMACK, S FEINBERG, J HE, QB LIU, HK YEH, PC AF DELACRUZ, SC MACCORMACK, S FEINBERG, J HE, QB LIU, HK YEH, PC TI EFFECT OF BEAM COHERENCE ON MUTUALLY PUMPED PHASE CONJUGATORS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID INCOHERENT BEAMS; MIRROR; LASERS; BATIO3 AB The performance of four different mutually pumped phase conjugators in barium titanate depends on the mutual coherence of the two input beams. In three of the conjugators the use of fully mutually coherent input beams enhances the overall phase-conjugate reflectivity. We find that backscattering and transmission gratings in the photorefractive crystal both contribute to the phase-conjugate signal and that their relative strength depends on the relative coherence of the two input beams. We numerically solve coupled-wave equations that include all gratings and find reasonable agreement between our theory and our experimental data. C1 UNIV SO CALIF,DEPT ELECT ENGN,LOS ANGELES,CA 90089. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV CALIF SANTA BARBARA,DEPT ELECT & COMP ENGN,SANTA BARBARA,CA 93106. RP DELACRUZ, SC (reprint author), UNIV SO CALIF,DEPT PHYS,LOS ANGELES,CA 90089, USA. RI Yeh, Pochi/A-2109-2010 NR 17 TC 22 Z9 22 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUL PY 1995 VL 12 IS 7 BP 1363 EP 1369 PG 7 WC Optics SC Optics GA RH119 UT WOS:A1995RH11900023 ER PT J AU LIBRESCU, L LIN, W NEMETH, MP STARNES, JH AF LIBRESCU, L LIN, W NEMETH, MP STARNES, JH TI THERMOMECHANICAL POSTBUCKLING OF GEOMETRICALLY IMPERFECT FLAT AND CURVED PANELS TAKING INTO ACCOUNT TANGENTIAL EDGE CONSTRAINTS SO JOURNAL OF THERMAL STRESSES LA English DT Article ID COMPOSITE PLATES AB A study of the effects of tangential edge constraints on the postbuckling response of flat and shallow curved panels subjected to thermal and mechanical loads is presented. The mechanical lends investigated are uniform compressive edge loads and transverse lateral pressure. The temperature fields considered are associated with spatially uniform healing over the thickness panel and a linear through-the-thickness temperature gradient. The structural model is based on a higher order transverse-shear deformation theory of shallow shells that incorporates the effects of geometric nonlinearities, initial geometric imperfections, and the tangential edge motion constraints. Simply supported panels are considered in which the tangential motion of the unloaded edges is either unrestrained partially restrained, or fully restrained. Results are presented for three-layer panels made from transversely isotropic materials, and a number of conclusions about the implications of the previously mentioned effects are outlined. C1 NASA,LANGLEY RES CTR,AIRCRAFT STRUCT BRANCH,DIV STRUCT MECH,HAMPTON,VA 23665. RP LIBRESCU, L (reprint author), VIRGINIA POLYTECH INST & STATE UNIV,DEPT ENGN SCI & MECH,BLACKSBURG,VA 24061, USA. NR 15 TC 39 Z9 39 U1 0 U2 1 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0149-5739 J9 J THERM STRESSES JI J. Therm. Stresses PD JUL-AUG PY 1995 VL 18 IS 4 BP 465 EP 482 DI 10.1080/01495739508946314 PG 18 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA RQ129 UT WOS:A1995RQ12900005 ER PT J AU CHAI, JC PARTHASARATHY, G LEE, HOS PATANKAR, SV AF CHAI, JC PARTHASARATHY, G LEE, HOS PATANKAR, SV TI FINITE-VOLUME RADIATIVE HEAT-TRANSFER PROCEDURE FOR IRREGULAR GEOMETRIES SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID RECTANGULAR ENCLOSURES; COORDINATE SYSTEM; FLOW AB A finite volume method for irregular geometries is presented in this article. The capability of the procedure is tested using five test problems. In these tests, transparent, absorbing, emitting, and anisotropically scattering media are examined. The solutions indicate that the finite volume method is a viable solution procedure for radiative heat transfer processes. C1 UNIV MINNESOTA,DEPT MECH ENGN,MINNEAPOLIS,MN 55455. NASA,LEWIS RES CTR,ICING TECHNOL BRANCH,CLEVELAND,OH 44135. RI Chai, John/A-3764-2010 NR 23 TC 89 Z9 90 U1 0 U2 6 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1995 VL 9 IS 3 BP 410 EP 415 DI 10.2514/3.682 PG 6 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RK192 UT WOS:A1995RK19200005 ER PT J AU DOGRA, VK MOSS, JN WILMOTH, RG TAYLOR, JC HASSAN, HA AF DOGRA, VK MOSS, JN WILMOTH, RG TAYLOR, JC HASSAN, HA TI BLUNT-BODY RAREFIED WAKES FOR EARTH ENTRY SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA/ASME 6th Joint Thermophysics and Heat Transfer Conference CY JUN 20-23, 1994 CL COLORADO SPRINGS, CO SP Amer Inst Aeronaut & Astronaut, Amer Soc Mech Engineers ID MODEL AB Direct simulation Monte Carlo (DSMC) and Navier-Stokes axisymmetric calculations are presented for hypersonic low-density flow about a 70-deg blunt cone afterbody configuration, The flow conditions simulated are those experienced by a space vehicle for an altitude range of 105-75 km during Earth entry. The entry velocity considered is 7 km/s. A steady vortex is predicted in the near wake for 75 and 85 km altitudes by both calculations, The flow remains attached for 95 and 105 km altitudes, Comparisons of DSMC and Navier-Stokes calculations for the wake flowfield become less and less favorable with increasing altitude. Comparisons of surface quantities shaw reasonable agreement between DSMC and Navier-Stokes calculations along the forebody. However, the surface quantities along the afterbody calculated from DSMC and Navier-Stokes calculations differ significantly at the higher altitudes. C1 NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681. N CAROLINA STATE UNIV,RALEIGH,NC 27695. RP DOGRA, VK (reprint author), SCI & TECHNOL CORP,AEROSP GRP,HAMPTON,VA 23666, USA. NR 22 TC 4 Z9 4 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1995 VL 9 IS 3 BP 464 EP 470 DI 10.2514/3.688 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RK192 UT WOS:A1995RK19200012 ER PT J AU NANCE, RP WILMOTH, RG MOON, B HASSAN, HA SALTZ, J AF NANCE, RP WILMOTH, RG MOON, B HASSAN, HA SALTZ, J TI PARALLEL MONTE-CARLO SIMULATION OF 3-DIMENSIONAL FLOW OVER A FLAT-PLATE SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA/ASME 6th Joint Thermophysics and Heat Transfer Conference CY JUN 20-23, 1994 CL COLORADO SPRINGS, CO SP Amer Inst Aeronaut & Astronaut, Amer Soc Mech Engineers ID MULTIPROCESSORS AB This article describes a parallel implementation of the direct simulation Monte Carlo (DSMC) method. Runtime library support is used for scheduling and execution of communication between nodes, and domain decomposition is performed dynamically to maintain a favorable load balance. Performance tests are conducted using the code to evaluate various remapping and remapping-interval policies, and it is shown that a one-dimensional chain-partitioning method works best for the problems considered, The parallel code is then used to simulate the Mach 20 nitrogen now over a finite thickness flat plate. It will be shown that the parallel algorithm produces results that are very similar to previous DSMC results, despite the increased resolution available, However, it yields significantly faster execution times than the scalar code, as well as very good load-balance and scalability characteristics. C1 NASA,LANGLEY RES CTR,DIV GAS DYNAM,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681. UNIV MARYLAND,DEPT COMP SCI,COLLEGE PK,MD 20742. RP NANCE, RP (reprint author), N CAROLINA STATE UNIV,RALEIGH,NC 27695, USA. NR 25 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 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1995 VL 9 IS 3 BP 471 EP 477 DI 10.2514/3.689 PG 7 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RK192 UT WOS:A1995RK19200013 ER PT J AU WILLIAMS, SD CURRY, DM CHAO, DC PHAM, VT AF WILLIAMS, SD CURRY, DM CHAO, DC PHAM, VT TI ABLATION ANALYSIS OF THE SHUTTLE ORBITER OXIDATION PROTECTED REINFORCED CARBON-CARBON SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article; Proceedings Paper CT AIAA/ASME 6th Joint Thermophysics and Heat Transfer Conference CY JUN 20-23, 1994 CL COLORADO SPRINGS, CO SP Amer Inst Aeronaut & Astronaut, Amer Soc Mech Engineers ID SILICON-CARBIDE; TEMPERATURE AB Reusable, oxidation-protected reinforced carbon-carbon has been successfully flown on all Shuttle Orbiter flights. Thermal testing of the silicon carbide-coated, reinforced carbon-carbon to determine its oxidation characteristics has been performed in convective (plasma Arc-Jet) heating facilities. surface sealant mass Loss was characterized as a function of temperature and pressure. High-temperature testing was performed to develop coating recession correlations for predicting performance at the over-temperature flight conditions associated with abort trajectories. Methods for using these test data to establish multimission reuse (i.e., mission life) and single mission limits are presented. C1 NASA,JOHNSON SPACE FLIGHT CTR,DIV STRUCT & MECH,HOUSTON,TX 77058. ROCKWELL INT CORP,DIV SPACE SYST,HOUSTON,TX 77058. RP WILLIAMS, SD (reprint author), LOCKHEED ENGN & SCI CO INC,HOUSTON,TX 77058, USA. NR 21 TC 12 Z9 12 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1995 VL 9 IS 3 BP 478 EP 485 DI 10.2514/3.690 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RK192 UT WOS:A1995RK19200014 ER PT J AU MILLER, JH TANNEHILL, JC WADAWADIGI, G EDWARDS, TA LAWRENCE, SL AF MILLER, JH TANNEHILL, JC WADAWADIGI, G EDWARDS, TA LAWRENCE, SL TI COMPUTATION OF HYPERSONIC FLOWS WITH FINITE CATALYTIC WALLS SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID NAVIER-STOKES CODE AB A computational study has been performed to explore the effects of finite catalytic walls on hypersonic flows. Boundary conditions for noncatalytic, fully catalytic, and finite catalytic walls have been incorporated into an upwind parabolized Navier-Stokes code. Nonequilibrium laminar airflows over sharp cones at 0 and 10 deg angle of attach were computed and the results are compared with previous results wherever possible. A study of finite catalytic cases was performed using varying recombination rates, Full ranges of catalycities were explored in the context of the surface energy balance as well as a constant wall temperature assumption, Detailed effects on specie concentrations, temperature, and heat transfer are presented. C1 NASA,AMES RES CTR,REACTING FLOW ENVIRONM BRANCH,MOFFETT FIELD,CA 94035. IOWA STATE UNIV SCI & TECHNOL,CTR COMPUTAT FLUID DYNAM,AMES,IA 50011. NASA,AMES RES CTR,APPL COMPUTAT AERODYANM BRANCH,MOFFETT FIELD,CA 94035. RP MILLER, JH (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT AEROSP ENGN & ENGN MECH,AMES,IA 50011, USA. NR 48 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 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD JUL-SEP PY 1995 VL 9 IS 3 BP 486 EP 493 DI 10.2514/3.691 PG 8 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA RK192 UT WOS:A1995RK19200015 ER PT J AU HESHMAT, H BREWE, D AF HESHMAT, H BREWE, D TI PERFORMANCE OF POWDER-LUBRICATED JOURNAL BEARINGS WITH MOS2 POWDER - EXPERIMENTAL-STUDY OF THERMAL PHENOMENA SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID QUASI-HYDRODYNAMIC MECHANISM AB Powder-lubricated, quasi-hydrodynamic journal bearings assist in controlling wear and hold promise for integration in outer space systems/mechanisms and in other hostile-environment applications where the use of conventional lubricants is impractical. Described herein are the thermal phenomena and an assessment of the thermal stability, heat generation and dissipation characteristics of slider-type, powder-lubricated bearings. Powder lubricant films provide lift and separate bearing surfaces and cause side leakage. The reduction in friction coefficient and, consequently, in the heat generated in the bearings, drastically reduces wear of the tribomaterials. Further, bearing side leakage carries away most of the heat generated by shear, reducing the heat to the critical bearing surfaces. Also presented are the thermohydrodynamic effects of powder lubrication (MoS2) on bearing performance criteria, e.g., temperature and friction coefficient as a function of speed and load including the effect of powder flow rate on bearing performance and wear. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP HESHMAT, H (reprint author), MECH TECHNOL INC,968 ALBANY SHAKER RD,LATHAM,NY 12110, USA. NR 11 TC 17 Z9 18 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD JUL PY 1995 VL 117 IS 3 BP 506 EP 512 DI 10.1115/1.2831282 PG 7 WC Engineering, Mechanical SC Engineering GA RP112 UT WOS:A1995RP11200020 ER PT J AU BELL, LD KAISER, WJ MANION, SJ MILLIKEN, AM PIKE, WT FATHAUER, RW AF BELL, LD KAISER, WJ MANION, SJ MILLIKEN, AM PIKE, WT FATHAUER, RW TI MEASUREMENTS OF LOCAL STRAIN VARIATION IN SI1-XGEX/SI HETEROSTRUCTURES SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 22nd Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI-22) CY JAN 08-12, 1995 CL SCOTTSDALE, AZ SP Amer Vacuum Soc, Electr Mat & Proc Div, USN, Off Naval Res ID ELECTRON-EMISSION MICROSCOPY; INTERFACE; SPECTROSCOPY; SCATTERING; TRANSPORT; SILICON; SURFACE; TEMPERATURE; LAYERS; SYSTEM AB The energy splitting of the conduction-band minimum of Si1-xGex due to strain has been directly measured by the application of ballistic-electron-emission microscope (BEEM) spectroscopy to Ag/Si1-xGex structures. Experimental values for this conduction-band splitting agree well with calculations. For Au/Si1-xGex, however, heterogeneity in the strain of the Si1-xGex layer is introduced by deposition of the Au. This variation is attributed to species interdiffusion, which produces a rough Si1-xGex surface. Preliminary modeling indicates that the observed roughness is consistent with the strain variation measured by BEEM. (C) 1995 American Vacuum Society. RP BELL, LD (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 27 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1995 VL 13 IS 4 BP 1602 EP 1607 DI 10.1116/1.587864 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA RP992 UT WOS:A1995RP99200035 ER PT J AU HUEBNER, WP PALOSKI, WH RESCHKE, MF BLOOMBERG, JJ AF HUEBNER, WP PALOSKI, WH RESCHKE, MF BLOOMBERG, JJ TI GEOMETRIC ADJUSTMENTS TO ACCOUNT FOR EYE ECCENTRICITY IN PROCESSING HORIZONTAL AND VERTICAL EYE AND HEAD MOVEMENT DATA SO JOURNAL OF VESTIBULAR RESEARCH-EQUILIBRIUM & ORIENTATION LA English DT Article DE GEOMETRIC RELATIONSHIPS; HEAD GEOMETRY; EYE ECCENTRIC; GAZE MODIFICATION ID COORDINATION; POSITION AB Neglecting the eccentric position of the eyes in the head can lead to erroneous interpretation of ocular motor data, particularly for near targets. We discuss the geometric effects that eye eccentricity has on the processing of target-directed eye and head movement data, and we highlight two approaches to processing and interpreting such data. The first approach involves determining the true position of the target with respect to the location of the eyes in space for evaluating the efficacy of gaze, and it allows calculation of retinal error directly from measured eye, head, and target data. The second approach effectively eliminates eye eccentricity effects by adjusting measured eye movement data to yield equivalent responses relative to a specified reference location (such as the center of head rotation). This latter technique can be used to standardize measured eye movement signals, enabling waveforms collected under different experimental conditions to be directly compared, both with the measured target signals and with each other. Mathematical relationships describing these approaches are presented for horizontal and vertical rotations, for both tangential and circumferential display screens, and efforts are made to describe the sensitivity of parameter variations on the calculated results. C1 NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,HOUSTON,TX 77058. RP HUEBNER, WP (reprint author), KRUG LIFE SCI INC,NEUROSCI LABS,MAIL CODE NL-37,1290 HERCULES,SUITE 120,HOUSTON,TX 77058, USA. NR 9 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0957-4271 J9 J VESTIBUL RES-EQUIL JI J. Vestib. Res.-Equilib. Orientat. PD JUL-AUG PY 1995 VL 5 IS 4 BP 299 EP 322 PG 24 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA RH542 UT WOS:A1995RH54200006 PM 7551214 ER PT J AU PEYTON, BW POTHEN, A YUAN, XQ AF PEYTON, BW POTHEN, A YUAN, XQ TI A CLIQUE TREE ALGORITHM FOR PARTITIONING A CHORDAL GRAPH INTO TRANSITIVE SUBGRAPHS SO LINEAR ALGEBRA AND ITS APPLICATIONS LA English DT Article ID SPARSE TRIANGULAR SOLUTION; PARALLEL; ELIMINATION AB A partitioning problem on chordal graphs that arises in the solution of sparse triangular systems of equations on parallel computers is considered. Roughly the problem is to partition a chordal graph G into the fewest transitively orientable subgraphs over all perfect elimination orderings of G, subject to a certain precedence relationship on its vertices. In earlier work, a greedy scheme that solved the problem by eliminating a largest subset of vertices at each step was described, and an algorithm implementing the scheme in time and space linear in the number of edges of the graph was provided. A more efficient greedy scheme, obtained by representing the chordal graph in terms of its maximal cliques, is described here. The new greedy scheme eliminates, in a specified order, a largest set of ''persistent leaves,'' a subset of the leaf cliques in the current graph, at each step. Several new results about minimal vertex separators in chordal graphs, and in particular, the concept of a critical separator of a leaf clique, are employed to prove that the new scheme solves the partitioning problem. We provide an algorithm implementing the scheme in time and space linear in the size of the clique tree. We anticipate that a critical separator of a leaf clique may be a useful concept in other problems on chordal graphs. C1 OLD DOMINION UNIV,DEPT COMP SCI,NORFOLK,VA 23529. NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. IBM CORP,CANADA LAB,N YORK,ON M3C 1H7,CANADA. RP PEYTON, BW (reprint author), OAK RIDGE NATL LAB,MATH SCI SECT,POB 2008,OAK RIDGE,TN 37831, USA. OI Pothen, Alex/0000-0002-3421-3325 NR 20 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0024-3795 J9 LINEAR ALGEBRA APPL JI Linear Alg. Appl. PD JUL PY 1995 VL 224 BP 553 EP 588 PG 36 WC Mathematics, Applied; Mathematics SC Mathematics GA RF722 UT WOS:A1995RF72200033 ER PT J AU OLSSON, P AF OLSSON, P TI SUMMATION BY PARTS, PROJECTIONS, AND STABILITY .1. SO MATHEMATICS OF COMPUTATION LA English DT Article AB We have derived stability results for high-order finite difference approximations of mixed hyperbolic-parabolic initial-boundary value problems (IBVP). The results are obtained using summation by parts and a new way of representing general linear boundary conditions as an orthogonal projection. By rearranging the analytic equations slightly, we can prove strict stability for hyperbolic-parabolic IBVP. Furthermore, we generalize our technique so as to yield stability on nonsmooth domains in two space dimensions. Using the same procedure, one can prove stability in higher dimensions as well. RP OLSSON, P (reprint author), NASA,AMES RES CTR,RIACS,MAIL STOP T20G-5,MOFFETT FIELD,CA 94035, USA. NR 9 TC 106 Z9 108 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0025-5718 J9 MATH COMPUT JI Math. Comput. PD JUL PY 1995 VL 64 IS 211 BP 1035 EP & DI 10.2307/2153482 PG 0 WC Mathematics, Applied SC Mathematics GA RJ128 UT WOS:A1995RJ12800007 ER PT J AU GOLDEN, DC MING, DW ZOLENSKY, ME AF GOLDEN, DC MING, DW ZOLENSKY, ME TI CHEMISTRY AND MINERALOGY OF OXIDATION-PRODUCTS ON THE SURFACE OF THE HOBA NICKEL-IRON METEORITE SO METEORITICS LA English DT Article AB An oxide layer adjacent to the surface of the Hoba Ni-Fe meteorite was analyzed chemically and mineralogically. Maghemite, magnetite, goethite and lepidocrocite were the main Fe minerals found in the oxide layer surrounding Hoba. Most of the Ni from the unweathered original meteorite was distributed among the above minerals with spinel-type oxides (maghemite and magnetite) having the largest Ni fraction. Some Ni migrated to the limestone in which the meteorite is embedded. No evidence for zaratite or akaganeite was found in the oxide layer. Sulfate derived from the oxidation of troilite precipitated as gypsum. Phosphate accumulation in limestone in contact with the meteorite is probably due to phosphate adsorbed on Fe-oxides. Maghemite with some magnetite was the oxidation product immediately next to the meteorite metal surface, which accommodated most of the Ni and Fe from the meteorite into its structure. Upon oxidation, some of the Ni, which was incorporated into calcite, was released. Cobalt associated with the oxides stayed within the oxide structure regardless of the oxidation state and did not migrate to the limestone. This suggests that Co may be a good tracer for oxides of meteoritic origin. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP GOLDEN, DC (reprint author), DUAL INC,16811 EL CAMINO REAL,SUITE 220,HOUSTON,TX 77058, USA. NR 14 TC 5 Z9 5 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 SN 0026-1114 J9 METEORITICS JI Meteoritics PD JUL PY 1995 VL 30 IS 4 BP 418 EP 422 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RM357 UT WOS:A1995RM35700008 ER PT J AU LINDER, JL GILBERT, JA AF LINDER, JL GILBERT, JA TI MODAL-ANALYSIS USING TIME-AVERAGE PANORAMIC HOLO-INTERFEROMETRY SO MODAL ANALYSIS-THE INTERNATIONAL JOURNAL OF ANALYTICAL AND EXPERIMENTAL MODAL ANALYSIS LA English DT Article AB Holographic analysis of complex structures is often difficult, One of the major problems is that the limited field of view available with current holographic inspection systems restricts the extent to which a full assessment of the structure may be made. In many cases, it becomes necessary to superimpose data extracted from spot views to characterize the modal response. This paper describes a new approach to modal analysis in which time-average holograms are recorded through a panoramic system. When inserted into a cylindrical structure, the system allows a relatively large portion of the surroundings to be illuminated and observed. The approach is applied to study the modal response of an aluminum ring. Quantitative results agree well with those obtained using standard impact hammer testing; qualitative comparisons are made between panoramic holo-interferograms recorded on the inner wall and those recorded on the outer surface using standard time-average holographic recording techniques, The main advantage of time-average panoramic holo-interferometry over conventional holo-interferometric recording is that displacement is recorded with nearly constant sensitivity over the entire field of view, making it simpler to qualitatively analyze the modal response. C1 UNIV ALABAMA,HUNTSVILLE,AL 35899. RP LINDER, JL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT & DYNAM LAB,MSFC,HUNTSVILLE,AL 35812, USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 SN 1066-0763 J9 MODAL ANAL JI Modal Anal.-Int. J. Analyt. Exp. Modal Anal. PD JUL PY 1995 VL 10 IS 3 BP 143 EP 151 PG 9 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA RM406 UT WOS:A1995RM40600002 ER PT J AU BENTS, DJ AF BENTS, DJ TI USE OF NAVY EXTERNAL COMBUSTION ENGINE TECHNOLOGY FOR ULTRA-HIGH ALTITUDE AIRCRAFT PROPULSION SYSTEMS - COMMENTS SO NAVAL ENGINEERS JOURNAL LA English DT Note RP BENTS, DJ (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NAVAL ENG INC PI ALEXANDRIA PA 1452 DUKE STREET, ALEXANDRIA, VA 22314-3458 SN 0028-1425 J9 NAV ENG J JI Nav. Eng. J. PD JUL PY 1995 VL 107 IS 4 BP 140 EP 142 PG 3 WC Engineering, Marine; Engineering, Civil; Oceanography SC Engineering; Oceanography GA RT312 UT WOS:A1995RT31200039 ER PT J AU KRAFT, RP BURROWS, DN GARMIRE, GP NOUSEK, JA JANESICK, JR VU, PN AF KRAFT, RP BURROWS, DN GARMIRE, GP NOUSEK, JA JANESICK, JR VU, PN TI SOFT-X-RAY SPECTROSCOPY WITH SUBELECTRON READNOISE CHARGE-COUPLED-DEVICES SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We demonstrate use of a charge-coupled device (CCD) with sub-electron readnoise performance as a non-dispersive X-ray spectrometer. The exceptionally low readnoise (0.9 electrons rms) was achieved by applying a floating gate output amplifier with 16 readouts per pixel. The soft X-ray quantum efficiency was enhanced over other front-side illuminated devices by using a novel thin-poly gate structure. The combination of sub-electron noise and good soft X-ray quantum efficiency have enabled us to detect photons in the EUV energy range (E < 100 eV) in photon counting mode with this detector. These low energy events are well separated from the readnoise floor. The measured energy resolution is 16.3 eV (FWHM) at Al L (E = 72 eV), 33.8 eV at C K-alpha (E = 277 eV) and 120 eV at Mn K-alpha (E = 5.9 keV). C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. LORAL FAIRCHILD IMAGING SENSORS,NEWPORT BEACH,CA 92688. RP KRAFT, RP (reprint author), PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,525 DAVEY LAB,UNIVERSITY PK,PA 16802, USA. NR 24 TC 44 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 JUL 1 PY 1995 VL 361 IS 1-2 BP 372 EP 383 DI 10.1016/0168-9002(95)00182-4 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA RH169 UT WOS:A1995RH16900046 ER PT J AU BARNARD, ST POTHEN, A SIMON, H AF BARNARD, ST POTHEN, A SIMON, H TI A SPECTRAL ALGORITHM FOR ENVELOPE REDUCTION OF SPARSE MATRICES SO NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS LA English DT Article DE ENVELOPE REDUCTION; EIGENVALUES OF GRAPHS; GIBBS-KING ALGORITHM; GIBBS-POOLE-STOCKMEYER ALGORITHM; LAPLACIAN MATRICES; REORDERING ALGORITHMS; REVERSE CUTHILL-MCKEE ALGORITHM; SPARSE MATRICES ID GRAPHS; EIGENVECTORS AB The problem of reordering a sparse symmetric matrix to reduce its envelope size is considered. A new spectral algorithm for computing an envelope-reducing reordering is obtained by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. This Laplacian eigenvector solves a continuous relaxation of a discrete problem related to envelope minimization called the minimum 2-sum problem. The permutation vector computed by the spectral algorithm is a closest permutation vector to the specified Laplacian eigenvector. Numerical results show that the new reordering algorithm usually computes smaller envelope sizes than those obtained from the current standards such as the Gibbs-Poole-Stockmeyer (GPS) algorithm or the reverse Cuthill-McKee (RCM) algorithm in SPARSPAK, in some cases reducing the envelope by more than a factor of two. C1 OLD DOMINION UNIV,DEPT COMP SCI,NORFOLK,VA 23529. SILICON GRAPH,MT VIEW,CA 94043. RP BARNARD, ST (reprint author), NASA,AMES RES CTR,CRAY RES INC,MAIL STOP T27A-1,MOFFETT FIELD,CA 94035, USA. OI Pothen, Alex/0000-0002-3421-3325 NR 34 TC 53 Z9 54 U1 1 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1070-5325 J9 NUMER LINEAR ALGEBR JI Numer. Linear Algebr. Appl. PD JUL-AUG PY 1995 VL 2 IS 4 BP 317 EP 334 DI 10.1002/nla.1680020402 PG 18 WC Mathematics, Applied; Mathematics SC Mathematics GA RW792 UT WOS:A1995RW79200001 ER PT J AU BRASUNAS, JC CUSHMAN, GM AF BRASUNAS, JC CUSHMAN, GM TI INTERFEROMETRIC BUT NONSPECTROSCOPIC TECHNIQUE FOR MEASURING THE THICKNESS OF A TRANSPARENT PLATE SO OPTICAL ENGINEERING LA English DT Article DE INTERFEROMETRY; OPTICAL TESTING; METROLOGY; THICKNESS ESTIMATION AB A simple technique is presented for estimating the thickness of a transparent plate. Using a laser source and detector, the transmitted light is measured as a function of angle of incidence. With prior knowledge of the refractive index of the plate at the laser wavelength, the observed fringes can be processed to estimate the plate thickness. The technique works with a modest degree of wedging, as long as fringes are discernible. Formal estimates of the error budget indicate the accuracy of this method is approximately 1 mu m. If fringes are measured versus both angle and wavelength, it should be possible to estimate both thickness and refractive index. RP BRASUNAS, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI brasunas, john/I-2798-2013 NR 10 TC 9 Z9 9 U1 0 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 JUL PY 1995 VL 34 IS 7 BP 2126 EP 2130 DI 10.1117/12.206585 PG 5 WC Optics SC Optics GA RJ305 UT WOS:A1995RJ30500036 ER PT J AU CUMMINGS, JJ CARLTON, DP POULAIN, FR FIKE, CD KEIL, LC BLAND, RD AF CUMMINGS, JJ CARLTON, DP POULAIN, FR FIKE, CD KEIL, LC BLAND, RD TI VASOPRESSIN EFFECTS ON LUNG LIQUID VOLUME IN FETAL SHEEP SO PEDIATRIC RESEARCH LA English DT Article ID ARGININE VASOPRESSIN; ION-TRANSPORT; INDUCED DECREASE; CELL MONOLAYERS; CORD BLOOD; SECRETION; RELEASE; LAMB; FLUID; GOATS AB The normal switch from placental to pulmonary gas exchange at birth requires rapid removal of liquid from the lungs. Previous reports contend that vasopressin may be important in regulating this process, but this notion derives from studies in which fetal sheep received very large doses of vasopressin that yielded plasma concentrations at least 10 times greater than those that have been measured during normal labor. To study the physiologic effects of vasopressin on lung liquid volume in fetal sheep, we made three sets of experiments. First, we measured plasma vasopressin concentrations [VP] in 15 late-gestation fetal sheep, five of which were at various stages of spontaneous labor. [VP] in these fetuses ranged from <1 (prelabor) to 31 (during labor) mu U/mL; postmortem extravascular lung water (EVLW) ranged from 4.5 to 14.5 g/g dry lung tissue. in a second series of studies, we measured EVLW in five sets of near-term (138 +/- 1 d, term = 147 d) twin fetal sheep that received an 8-h i.v. infusion of either isotonic saline (control twin) or AVP (AVP-treated twin) at a rate of similar to 1 (mU/kg)/min. This dose was chosen to mimic [VP] measured in fetuses that had been studied during labor. [VP] did not change in the control twins, whereas [VP] increased from 1.8 +/- 1.0 to 27.7 +/- 3.5 mu U/mL in treated twins. There was a small, statistically significant difference in EVLW between twins that received AW and untreated twins (11.9 +/- 1.8 versus 14.6 +/- 2.8 g/g dry lung). in a third series of studies, we measured net production of lung liquid (Jv) by an indicator dilution technique in 16 fetal sheep that received an i.v. infusion of isotonic saline for 2 h followed by AVP for up to 8 h. [VP] averaged 23.4 +/- 6.5 mu U/mL during AVP infusion. For six fetuses that were studied at <132 d (128 +/- 4 d) gestation, Jv did not change during AVP infusion (11.1 +/- 6.7 mL/h versus control, 10.2 +/- 4.7 mL/h); for 10 fetuses >132 d (135 +/- 2 d) gestation, Jv decreased from 11.3 4.7 mL/h during the control period to 8.6 +/- 5.4 mL/h during AVP infusion. Net secretion of lung liquid did not switch to net absorption in any of the 16 fetuses that received AVP. Thus, i.v. infusion of AVP, at a rate designed to mimic [VP] measured during spontaneous labor, led to modest reductions in Jv and EVLW, but did not cause net absorption of lung liquid in late-gestation fetal sheep. C1 UNIV UTAH, HLTH SCI CTR, DEPT PEDIAT, SALT LAKE CITY, UT 84132 USA. UNIV CALIF SAN FRANCISCO, CARDIOVASC RES INST, SAN FRANCISCO, CA 94143 USA. UNIV CALIF SAN FRANCISCO, DEPT PEDIAT, SAN FRANCISCO, CA 94143 USA. STATE UNIV NEW YORK BUFFALO, DEPT PEDIAT, BUFFALO, NY 14222 USA. NASA, AMES RES CTR, DIV SPACE LIFE SCI, MOFFETT FIELD, CA 94035 USA. FU NHLBI NIH HHS [HL-07185, HL-40802, HL-27356] NR 42 TC 5 Z9 5 U1 0 U2 1 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 0031-3998 EI 1530-0447 J9 PEDIATR RES JI Pediatr. Res. PD JUL PY 1995 VL 38 IS 1 BP 30 EP 35 DI 10.1203/00006450-199507000-00006 PG 6 WC Pediatrics SC Pediatrics GA RF130 UT WOS:A1995RF13000006 PM 7478793 ER PT J AU COSTINER, S TAASAN, S AF COSTINER, S TAASAN, S TI SIMULTANEOUS MULTIGRID TECHNIQUES FOR NONLINEAR EIGENVALUE PROBLEMS - SOLUTIONS OF THE NONLINEAR SCHRODINGER-POISSON EIGENVALUE PROBLEM IN 2 AND 3 DIMENSIONS SO PHYSICAL REVIEW E LA English DT Article ID MULTILEVEL AB Algorithms for nonlinear eigenvalue problems (EP's) often require solving self-consistently a large number of EP's. Convergence difficulties may occur if the solution is not sought in an appropriate region, if global constraints have to be satisfied, or if close or equal eigenvalues are present. Multigrid (MG) algorithms for nonlinear problems and for EP's obtained from discretizations of partial differential EP have often been shown to be more efficient than single level algorithms. This paper presents MG techniques and a MG algorithm for nonlinear Schrodinger-Poisson EP's. The algorithm overcomes the above mentioned difficulties combining the following techniques: a MG simultaneous treatment of the eigenvectors and nonlinearity, and with the global constraints; MG stable subspace continuation techniques for the treatment of nonlinearity; and a MG projection coupled with backrotations for separation of solutions. These techniques keep the solutions in an appropriate region, where the algorithm converges fast, and reduce the large number of self-consistent iterations to only a few or one MG simultaneous iteration. The MG projection makes it possible to efficiently overcome difficulties related to clusters of close and equal eigenvalues. Computational examples for the nonlinear Schrodinger-Poisson EP in two and three dimensions, presenting special computational difficulties, that are due to the nonlinearity and to the equal and closely clustered eigenvalues are demonstrated. For these cases, the algorithm requires O(qN) operations for the calculation of q eigenvectors of size N and for the corresponding eigenvalues. One MG simultaneous cycle per fine level was performed. The total computational cost is equivalent to only a few Gauss-Seidel relaxations per eigenvector. An asymptotic convergence rate of 0.15 per MG cycle is attained. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681. RP COSTINER, S (reprint author), WEIZMANN INST SCI,DEPT APPL MATH & COMP SCI,IL-76100 REHOVOT,ISRAEL. NR 26 TC 22 Z9 24 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUL PY 1995 VL 52 IS 1 BP 1181 EP 1192 DI 10.1103/PhysRevE.52.1181 PN B PG 12 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA RK547 UT WOS:A1995RK54700051 ER PT J AU CHAMPNEY, JM DOBROVOLSKIS, AR CUZZI, JN AF CHAMPNEY, JM DOBROVOLSKIS, AR CUZZI, JN TI A NUMERICAL TURBULENCE MODEL FOR MULTIPHASE FLOWS IN THE PROTOPLANETARY NEBULA SO PHYSICS OF FLUIDS LA English DT Article ID SOLAR NEBULA; PLANETESIMALS; DUST AB It is thought that planets form from solid particles in a flattened, rotating, 99% gaseous nebula. These grains gradually coagulate into millimeter-to-meter sized aggregates which settle toward the midplane of the nebula. It is widely believed that the resulting dense layer eventually becomes gravitationally unstable and collapses into ''planetesimals.'' A new numerical model is presented to simulate the predominant processes (gravitation, vertical convection, and shear-driven turbulence) during the stage while the particulate material is still dispersed about the midplane of the nebula. In our previous work, particles were assumed to be spheres of a single radius; in the present work, particles are spheres of different radii. Results indicate that neither a broad nor a narrow distribution of particle sizes is likely to become gravitationally unstable. (C) 1995 American Institute of Physics. C1 UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP CHAMPNEY, JM (reprint author), APPL & THEORET MECH INC,PALO ALTO,CA 94306, USA. NR 14 TC 24 Z9 24 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUL PY 1995 VL 7 IS 7 BP 1703 EP 1711 DI 10.1063/1.868486 PG 9 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RJ659 UT WOS:A1995RJ65900016 ER PT J AU HILAIRE, E PAULSEN, AQ BROWN, CS GUIKEMA, JA AF HILAIRE, E PAULSEN, AQ BROWN, CS GUIKEMA, JA TI MICROGRAVITY AND CLINOROTATION CAUSE REDISTRIBUTION OF FREE CALCIUM IN SWEET CLOVER COLUMELLA CELLS SO PLANT AND CELL PHYSIOLOGY LA English DT Article DE CALCIUM; MELILOTUS ALBA L; MICROGRAVITY; ROOT; SPACEFLIGHT ID PLANT-CELLS; LOCALIZATION; ROOTS; ANTIMONATE; CLINOSTAT; CA2+ AB In higher plants, calcium redistribution is believed to be crucial for the root to respond to a change in the direction of the gravity vector. To test the effects of clinorotation and microgravity on calcium localization in higher plant roots, sweet clover (Melilotus alba L.) seedlings were germinated and grown for two days on a slow rotating clinostat or in microgravity on the US Space Shuttle flight STS-60. Subsequently, the tissue was treated with a fixative containing antimonate (a calcium precipitating agent) during clinorotation or in microgravity and processed for electron microscopy. In root columella cells of clinorotated plants, antimonate precipitates were localized adjacent to the cell wall in a unilateral manner. Columella cells exposed to microgravity were characterized by precipitates mostly located adjacent to the proximal and lateral cell wall. In all treatments some punctate precipitates were associated with vacuoles, amyloplasts, mitochondria, and euchromatin of the nucleus. A quantitative study revealed a decreased number of precipitates associated with the nucleus and the amyloplasts in columella cells exposed to microgravity as compared to ground controls. These data suggest that roots perceive a change in the gravitational field, as produced by clinorotation or space flights, and respond respectively differently by a redistribution of free calcium. C1 DYNAMAC CORP, PLANT SPACE BIOL LAB, KENNEDY SPACE CTR, FL 32899 USA. RP HILAIRE, E (reprint author), KANSAS STATE UNIV AGR & APPL SCI, NASA, SPECIALIZED CTR RES & TRAINING GRAVITAT BIOL, DIV BIOL, MANHATTAN, KS 66506 USA. RI Guikema, James/C-1313-2010 NR 43 TC 19 Z9 21 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0032-0781 EI 1471-9053 J9 PLANT CELL PHYSIOL JI Plant Cell Physiol. PD JUL PY 1995 VL 36 IS 5 BP 831 EP 837 PG 7 WC Plant Sciences; Cell Biology SC Plant Sciences; Cell Biology GA RM738 UT WOS:A1995RM73800011 PM 11536706 ER PT J AU SHRADER, CR GEHRELS, N AF SHRADER, CR GEHRELS, N TI RECENT RESULTS FROM THE COMPTON GAMMA-RAY OBSERVATORY SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Review ID EGRET TELESCOPE; RADIATION; BURSTS; BATSE; SN-1987A; EMISSION; SPECTRA; GEMINGA; NEBULA; GALAXY AB A selection of recent scientific findings from the Compton Gamma Ray Observatory is presented. In gamma-ray burst astrophysics, notable is the dramatic confirmation that bursts are isotropic but spatially inhomogeneous in their distribution. They exhibit temporal effects consistent with a time dilation as expected for a cosmologically distributed population; however alternate explanations cannot be ruled out. Also notable is the detection of delayed, nonthermal high-energy (MeV and GeV) gamma-ray emission possibly indicating that particle acceleration lasts long after the prompt emission. In active galactic nuclei (AGN) research, a new class of objects, the gamma-ray blazars, has been identified and a possible additional subclass of ''MeV bump'' quasars has emerged as well. Both of these AGN subclasses emit the bulk of their bolometric luminosity above similar to 1 MeV. Gamma-ray bright Seyfert galaxies exhibit spectra which cut off at similar to 100 keV indicative of thermal emission from plasma near the central engine, which has significant implications for both AGN emission models and the origin of the diffuse X-ray background. The detection of nuclear emission lines from Co-57 in, SN 1987A, Ti-44 in, C,as A, and the mapping of emission from Al-26 along the galactic plane all have important implications for our understanding of nucleosynthesis and supernova dynamics. Monitoring of the Galactic Center electron-positron annihilation source has failed to reveal any dramatic variability episodes as have been reported in the past by some previous experiments, and a model consisting of a bulge component and a disk component has begun to emerge. A dramatic increase in the number of known radio pulsars with gamma-ray emission, from 2 to 7, and gamma-ray light curves of unprecedented detail have provided tremendous insight into pulsar research. Nearly uninterrupted daily monitoring of a number of accretion-driven X-ray pulsars has provided an unprecedented view of their torque histories. A transition from spin-up to a spin-down state of GX 1+4 has recently been documented. Orbital solutions for the binary systems OAO 1657-415 and A 0535+26 have been derived, and for A 0535+26 a cyclotron absorption feature, suggestive of magnetic field strengths of >10(13) Gauss has been detected. The study of X-ray novae, which thrived in the late 1970's has experienced a rejuvenation of significant proportions as a result of the Compton Gamma Ray Observatory's all-sky monitoring capabilities and programmatic flexibility. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. RP SHRADER, CR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 6681,GREENBELT,MD 20771, USA. RI Gehrels, Neil/D-2971-2012 NR 120 TC 6 Z9 6 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JUL PY 1995 VL 107 IS 713 BP 606 EP 616 DI 10.1086/133600 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RH329 UT WOS:A1995RH32900002 ER PT J AU BADHWAR, GD ATWELL, W BENTON, EV FRANK, AL KEEGAN, RP DUDKIN, VE KARPOV, ON POTAPOV, YV AKOPOVA, AB MAGRADZE, NV MELKUMYAN, LV RSHTUNI, SB AF BADHWAR, GD ATWELL, W BENTON, EV FRANK, AL KEEGAN, RP DUDKIN, VE KARPOV, ON POTAPOV, YV AKOPOVA, AB MAGRADZE, NV MELKUMYAN, LV RSHTUNI, SB TI A STUDY OF THE RADIATION ENVIRONMENT ON BOARD THE SPACE-SHUTTLE FLIGHT STS-57 SO RADIATION MEASUREMENTS LA English DT Article ID LOW EARTH ORBIT; LINEAR ENERGY-TRANSFER; COSMIC-RADIATION; SPECTRA AB A joint NASA-Russian study of the radiation environment inside a SPACEHAB 2 locker on Space Shuttle flight STS-57 was conducted. The Shuttle flew in a nearly circular orbit of 28.5 degrees inclination and 462 km altitude. The locker carried a charged particle spectrometer, a tissue equivalent proportional counter (TEPC), and two area passive detectors consisting of combined NASA plastic nuclear track detectors (PNTDs) and thermoluminescent detectors (TLDs), and Russian nuclear emulsions, PNTDs and TLDs. All the detector systems were shielded by the same Shuttle mass distribution. This makes possible a direct comparison of the various dose measurement techniques. In addition, measurements of the neutron energy spectrum were made using the proton recoil technique. The results show good agreement between the integral LET spectrum of the combined galactic and trapped particles using the tissue equivalent proportional counter and track detectors between about 15 keV/mu m and 200 keV/mu m. The LET spectrum determined from nuclear emulsions was systematically lower by about 50%, possibly due to emulsion fading. The results show that the TEPC measured an absorbed dose 20% higher than the TLDs, due primarily to an increased TEPC response to neutrons and a low sensitivity of TLDs to high LET particles under normal processing techniques. There is a significant flux of high energy neutrons that is currently not taken into consideration in dose equivalent calculations. The results of the analysis of the spectrometer data will be reported separately. C1 ROCKWELL INT CORP,DIV SPACE SYST,HOUSTON,TX 77058. UNIV SAN FRANCISCO,DEPT PHYS,SAN FRANCISCO,CA 94117. RES CTR SPACECRAFT RADIAT SAFETY,MOSCOW 123182,RUSSIA. YEREVAN PHYS INST,YEREVAN 375036,ARMENIA. RP BADHWAR, GD (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 22 TC 26 Z9 27 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD JUL PY 1995 VL 24 IS 3 BP 283 EP 289 DI 10.1016/1350-4487(95)00007-2 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA RL833 UT WOS:A1995RL83300008 PM 11539130 ER PT J AU NGHIEM, SV KWOK, R YUEH, SH KONG, JA HSU, CC TASSOUDJI, MA SHIN, RT AF NGHIEM, SV KWOK, R YUEH, SH KONG, JA HSU, CC TASSOUDJI, MA SHIN, RT TI POLARIMETRIC SCATTERING FROM LAYERED MEDIA WITH MULTIPLE SPECIES OF SCATTERERS SO RADIO SCIENCE LA English DT Article ID STRONG PERMITTIVITY FLUCTUATIONS; SEA ICE; MODEL; SNOW AB Geophysical media are usually heterogeneous and contain multiple species of scatterers. In this paper a model is presented to calculate effective permittivities and polarimetric backscattering coefficients of multispecies-layered media. The same physical description is consistently used in the derivation of both permittivities and scattering coefficients. The strong permittivity fluctuation theory is extended to account for the multiple species of scatterers with a general ellipsoidal shape whose orientations are randomly distributed. Under the distorted Born approximation, polarimetric scattering coefficients are obtained. These calculations are applicable to the special cases of spheroidal and spherical scatterers. The model is used to study effects of scatterer shapes and multispecies mixtures on polarimetric signatures of heterogeneous media. The multispecies model accounts for moisture content in scattering media such as snowpack in an ice sheet. The results indicate a high sensitivity of backscatter to moisture with a stronger dependence for drier snow and ice grain size is important to the backscatter. For frost-covered saline ice, model results for bare ice are compared with measured data at C band and then the frost flower formation is simulated with a layer of fanlike ice crystals including brine infiltration over a rough interface. The results with the frost cover suggest a significant increase in scattering coefficients and a polarimetric signature closer to isotropic characteristics compared to the thin saline ice case. C1 MIT,DEPT ELECT ENGN & COMP SCI,CAMBRIDGE,MA 02139. MIT,ELECTR RES LAB,CAMBRIDGE,MA 02139. RP NGHIEM, SV (reprint author), CALTECH,JET PROP LAB,MS 300-235,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 26 TC 22 Z9 22 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1995 VL 30 IS 4 BP 835 EP 852 DI 10.1029/95RS01247 PG 18 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA RL422 UT WOS:A1995RL42200005 ER PT J AU DURDEN, SL HADDAD, ZS IM, E KITIYAKARA, A LI, FK TANNER, AB WILSON, WJ AF DURDEN, SL HADDAD, ZS IM, E KITIYAKARA, A LI, FK TANNER, AB WILSON, WJ TI MEASUREMENT OF RAINFALL PATH ATTENUATION NEAR NADIR - A COMPARISON OF RADAR AND RADIOMETER METHODS AT 13.8 GHZ SO RADIO SCIENCE LA English DT Article ID SPACEBORNE RADAR; RETRIEVAL AB Rain profile retrieval from spaceborne radar is difficult because of the presence of attenuation at the higher frequencies planned for these systems. One way to reduce the ambiguity in the retrieved rainfall profile is to use the path-integrated attenuation as a constraint. Two techniques for measuring the path-integrated attenuation have been proposed: the radar surface reference technique and microwave radiometry. We compare these two techniques using data acquired by the Airborne Rain Mapping Radar (ARMAR) 13.8-GHz airborne radar and radiometer during the Tropical Ocean-Global Atmosphere Coupled Ocean Atmosphere Response Experiment (TOGA COARE) in the western Pacific Ocean in early 1993. The two techniques have a mean difference close to zero for both nadir and 10 degrees incidence. The RMS difference is 1.4 dB and is reduced to 1 dB or less if points where the radiometer was likely saturated are excluded. Part of the RMS difference can be attributed to variability in the ocean surface cross section due to wind effects and possibly rain effects. The results presented here are relevant for the Tropical Rainfall Measuring Mission, which will include a 13.8-GHz precipitation radar. RP DURDEN, SL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 300-235,PASADENA,CA 91109, USA. NR 15 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1995 VL 30 IS 4 BP 943 EP 947 DI 10.1029/95RS01451 PG 5 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA RL422 UT WOS:A1995RL42200013 ER PT J AU FARRELL, WM AF FARRELL, WM TI FINE-STRUCTURE OF THE AURORAL KILOMETRIC RADIATION - A FERMI ACCELERATION PROCESS SO RADIO SCIENCE LA English DT Article ID DECAMETRIC RADIATION; PLASMA CAVITY; GENERATION; MAGNETOSPHERE; MECHANISM; REGION; MODEL; WAVE AB The fine structure of the auroral kilometric radiation is explained as a nonlinear interaction between the locally generated cyclotron emission created in an electron plasma cavity and the cavity boundary. Specifically, it is demonstrated that broadband cyclotron emission can form discrete tones after numerous interactions with an oscillating boundary that has quasi-monochromatic wavelike motion. This boundary will Doppler shift most radio photons in a stochastic way, creating a diffuse background radio component. However, some radio photons will have regular, stable frequencies that form discrete tones that overlie on the diffuse background emission. The discrete tones are created in situations where the photon travel;time in the cavity is an integer multiple of the boundary oscillation period, this effect establishing a resonance between the boundary oscillations and photon. A set of coupled nonlinear equations is used to describe the radio photon/cavity boundary interaction. Effects of wave growth in the local density cavity and boundary reflections are also included. As the character of the cavity slowly changes, the resonance condition also changes in an adiabatic way, shifting the resonance to different frequencies. The net result is the creation of drifting radio tones which are comparable to those actually observed on radio spectrograms of the auroral kilometric radiation. RP FARRELL, WM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. RI Farrell, William/I-4865-2013 NR 30 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JUL-AUG PY 1995 VL 30 IS 4 BP 961 EP 973 DI 10.1029/95RS00832 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA RL422 UT WOS:A1995RL42200015 ER PT J AU KARAM, MA AMAR, F FUNG, AK MOUGIN, E LOPES, A LEVINE, DM BEAUDOIN, A AF KARAM, MA AMAR, F FUNG, AK MOUGIN, E LOPES, A LEVINE, DM BEAUDOIN, A TI A MICROWAVE POLARIMETRIC SCATTERING MODEL FOR FOREST CANOPIES BASED ON VECTOR RADIATIVE-TRANSFER THEORY SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID VEGETATION; SIGNATURE; LAYER AB A microwave polarimetric scattering model for a forest canopy is developed based on the iterative solution of the vector radiative transfer equations up to the second order. The forest canopy constituents (branches, leaves, stems, and trunks) are embedded in a multi-layered medium over a rough interface. The branches, stems, and trunks are modeled as finite randomly oriented cylinders. Deciduous leaves are modeled as randomly oriented discs and coniferous leaves are modeled as randomly oriented needles. The vector radiative transfer equations contain nondiagonal extinction matrices that account for the difference in propagation constants and the attenuation rates between the vertical and horizontal polarizations. For a plane wave exciting the canopy, the average Mueller matrix is formulated, and then used to determine the linearly polarized backscattering coefficients including both the copolarized and cross-polarized power returns. Comparisons of the model with measurements from Les Landes Forest of France showed good agreements over a wide frequency band and gave a quantitative understanding of the relation between the backscattering coefficients and the age of the trees in the forest and forest biomass. C1 GENCORP AEROJET,DIV ELECTR SYST,AZUSA,CA. UNIV TEXAS,DEPT ELECT ENGN,WAVE SCATTERING RES CTR,ARLINGTON,TX 76019. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. CTR ETUD SPATIALE RAYONNEMENTS,TOULON,FRANCE. NR 30 TC 60 Z9 63 U1 0 U2 3 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUL PY 1995 VL 53 IS 1 BP 16 EP 30 DI 10.1016/0034-4257(95)00048-6 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RN884 UT WOS:A1995RN88400002 ER PT J AU DUONG, T KEMENY, S DAUD, T THAKOOR, A SAUNDERS, C CARSON, J AF DUONG, T KEMENY, S DAUD, T THAKOOR, A SAUNDERS, C CARSON, J TI ANALOG 3-D NEUROPROCESSOR FOR FAST FRAME FOCAL-PLANE IMAGE-PROCESSING SO SIMULATION LA English DT Article DE NEUROPROCESSOR; CASCADE BACKPROPAGATION; ANALOG VLSI; 3-D STACK AB A particularly challenging neural network application requiring high-speed and intensive image processing capability is target acquisition and discrimination. It requires spatio-temporal recognition of point and resolved targets at high speeds. A reconfigurable neural architecture may discriminate targets forgets from clutter or classify targets once resolved. By mating a 64 x 64 pixel array infrared (IR) image sensor to a 3-D stack (cube) of 64 neural-net ICs along respective edges, every pixel would directly input to a neural network, thereby processing the infor-mation with full parallelism. Being mated to the infrared sensor array, the cube would operate at 90 degrees K temperature with <250 nanosecond signal processing speed and a low power consumption of only similar to 2 watts. For low power and compactness in hardware, the emphasis has been on parallelism and analog signal processing. A versatile reconfigurable circuit is presented that offers a variety of neural architectures: multilayer perceptron, template matching with winner-take-all (WTA) circuitry, and a new architecture of cascade backpropagation (CBP). Special designs of analog neuron and synapse implemented in VLSI are presented which bear out high speed response both at room and low temperatures with synapse-neuron signal propagation times of similar to 100 ns. The CBP learning algorithm is illustrated by solving in simulation the nonlinear 6-bit parity problem. Results show that this algorithm is robust even with synaptic resolutions limited to 5 bits. Therefore, it is particularly suitable for hardware implementation. C1 IRVINE SENSORS CORP,INTEGRATED CIRCUIT DESIGN,COSTA MESA,CA 92626. IRVINE SENSORS CORP,ADV TECHNOL OPERAT,COSTA MESA,CA 92626. CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,DIV ELECTR & CONTROLS,PASADENA,CA 91109. CALTECH,JET PROP LAB,CONCURRENT PROC DEVICES GRP,PASADENA,CA 91109. NR 18 TC 0 Z9 0 U1 0 U2 0 PU SIMULATION COUNCILS INC PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92117 SN 0037-5497 J9 SIMULATION JI Simulation PD JUL PY 1995 VL 65 IS 1 BP 11 EP 25 DI 10.1177/003754979506500103 PG 15 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA RP483 UT WOS:A1995RP48300002 ER PT J AU SIGLER, MF AF SIGLER, MF TI BAR-CODED MEASURING SYSTEMS - REPLY SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Note RP SIGLER, MF (reprint author), NATL MARINE FISHERIES SERV,ALASKA FISHERIES SCI CTR,AUKE BAY LAB,11305 GLACIER HIGHWAY,JUNEAU,AK 99801, USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 1995 VL 124 IS 4 BP 641 EP 642 DI 10.1577/1548-8659-124.4.641 PG 2 WC Fisheries SC Fisheries GA RK641 UT WOS:A1995RK64100017 ER PT J AU SLINEY, HE DELLACORTE, C LUKASZEWICZ, V AF SLINEY, HE DELLACORTE, C LUKASZEWICZ, V TI THE TRIBOLOGY OF PS212 COATINGS AND PM212 COMPOSITES FOR THE LUBRICATION OF TITANIUM 6A1-4V COMPONENTS OF A STIRLING ENGINE SPACE POWER-SYSTEM SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 49th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 01-05, 1994 CL PITTSBURGH, PA SP Soc Tribologists & Lubricat Engineers DE FRICTION; WEAR AND FAILURE; MATERIALS PROPERTIES AND TRIBOLOGY AB The Stirling space power machine incorporates a linear alternator to generate electrical power. The alternator is a reciprocating device that is driven by a solar or nuclear-powered Stirling engine. The power piston and cylinder are made of titanium 6A1-4V (Ti6-4) alloy, and are designed to be lubricated by a hydrodynamically-generated gas film. Rubbing occurs during starts and stops and there is the Possibility of an occasional high speed rub. Since titanium is known to have a severe galling tendency in sliding contacts, a ''back-up,'' self-lubricating coating on the cylinder and/or the piston is needed. This report describes the results of a research Program to study the lubrication of Ti6-4 with the following chromium carbide based materials: plasma-sprayed PS212 coatings and sintered PM212 counterfaces. Program objectives are to achieve adherent coatings on Ti6-4 and to measure the friction and wear characteristics of the following sliding combinations under conditions simulative of the Stirling-driven space power linear altanator: Ti6-4/Ti6-4 baseline, Ti6-4/PS212-coated Ti6-4, and PS212-coated Ti6-4/PM212. C1 CALSPAN CORP,CLEVELAND,OH 44135. RP SLINEY, HE (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 14 TC 18 Z9 19 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 JUL PY 1995 VL 38 IS 3 BP 497 EP 506 DI 10.1080/10402009508983435 PG 10 WC Engineering, Mechanical SC Engineering GA RG463 UT WOS:A1995RG46300002 ER PT J AU JONES, WR AF JONES, WR TI PROPERTIES OF PERFLUOROPOLYETHERS FOR SPACE APPLICATIONS SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT ASME/STLE Tribology Conference CY OCT 16-19, 1994 CL MAUI, HI SP Amer Soc Mech Engineers, Soc Tribologists & Lubricat Engineers DE SPACE LUBRICANTS; AEROSPACE ID OXIDATIVE-DEGRADATION REACTIONS; PERFLUOROPOLYALKYLETHER OIL; PERFLUOROALKYL ETHERS; HYDRAULIC FLUIDS; TEMPERATURE; LUBRICANTS; VISCOSITY; OXIDE); STEEL; FEF3 AB The perfluoropolyether (PFPE) class of liquid lubricants has been used for space applications for over two decades. At first, these fluids performed satisfactorily, as early spacecraft placed few demands on their performance. However, as other spacecraft components have become more reliable and lifetimes have been extended, PFPE lubricant deficiencies have been exposed. Therefore, the objective of this paper is to review the PFPE properties that are important for successful long ten operation in space. RP JONES, WR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 52 TC 40 Z9 41 U1 0 U2 7 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1995 VL 38 IS 3 BP 557 EP 564 DI 10.1080/10402009508983442 PG 8 WC Engineering, Mechanical SC Engineering GA RG463 UT WOS:A1995RG46300009 ER PT J AU PACIOREK, KJL MASUDA, SR LIN, WH JONES, WR HELMICK, LS AF PACIOREK, KJL MASUDA, SR LIN, WH JONES, WR HELMICK, LS TI THERMAL-OXIDATIVE PRETREATMENT AND EVALUATION OF POLY(HEXAFLUOROPROPENE OXIDE) FLUIDS SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT ASME/STLE Tribology Conference CY OCT 16-19, 1994 CL MAUI, HI SP Amer Soc Mech Engineers, Soc Tribologists & Lubricat Engineers DE PERFLUOROPOLYETHERS; OXIDATIVE STABILITY ID PERFLUOROPOLYALKYLETHER OIL; HYDRAULIC FLUIDS; SOLID-SURFACES; LUBRICANTS; PERFLUOROPOLYETHERS; TEMPERATURE; DEGRADATION; POLYETHER; STEEL; FEF3 AB Two commercial poly(hexafluoropropene oxide) fluids were thermally pretreated at 343 degrees C in pure oxygen. IR and NMR spectra indicate that this pretreatment was effective in removing hydrogen end-capped impurities. A decrease in the quantity of volatile material produced during thermal oxidative decomposition and increase in the thermal decomposition temperature indicated improvement in the stability of the fluids. However, this pretreatment failed to render the fluids completely stable in oxidizing atmospheres at 316 degrees C in the presence of metal alloys. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. CEDARVILLE COLL,CEDARVILLE,OH. RP PACIOREK, KJL (reprint author), TECHNOLUBE PROD CO,LOS ANGELES,CA, USA. NR 28 TC 2 Z9 2 U1 0 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0569-8197 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1995 VL 38 IS 3 BP 571 EP 576 DI 10.1080/10402009508983444 PG 6 WC Engineering, Mechanical SC Engineering GA RG463 UT WOS:A1995RG46300011 ER PT J AU MARTIN, TZ ORTON, GS TRAVIS, LD TAMPPARI, LK CLAYPOOL, I AF MARTIN, TZ ORTON, GS TRAVIS, LD TAMPPARI, LK CLAYPOOL, I TI OBSERVATION OF SHOEMAKER-LEVY IMPACTS BY THE GALILEO PHOTOPOLARIMETER RADIOMETER SO SCIENCE LA English DT Article AB The Galileo Photopolarimeter Radiometer experiment made direct photometric observations at 678 and 945 nanometers of several comet Shoemaker-Levy 9 fragments impacting with Jupiter. Initial flashes occurred at (fragment G) 18 July 1994 07:33:32, (H) 18 July 19:31:58, (L) 19 July 22:16:48, and (Q1) 20 July 20:13:52 [equivalent universal time coordinated (UTC) observed at Earth], with relative peak 945-nanometer brightnesses of 0.87, 0.67, 1.00, and 0.42, respectively. The light curves show a 2-second rise to maximum, a 10-second plateau, and an accelerating falloff. The Q1 event, observed at both wavelengths, yielded a color temperature of more than 10,000 kelvin at its peak. C1 GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP MARTIN, TZ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 169-237,PASADENA,CA 91109, USA. NR 23 TC 22 Z9 22 U1 1 U2 1 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 30 PY 1995 VL 268 IS 5219 BP 1875 EP 1879 DI 10.1126/science.268.5219.1875 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RF990 UT WOS:A1995RF99000031 PM 17797529 ER PT J AU DEPATER, I HEILES, C WONG, M MADDALENA, RJ BIRD, MK FUNKE, O NEIDHOEFER, J PRICE, RM KESTEVEN, M CALABRETTA, M KLEIN, MJ GULKIS, S BOLTON, SJ FOSTER, RS SUKUMAR, S STROM, RG LEPOOLE, RS SPOELSTRA, T ROBISON, M HUNSTEAD, RW CAMPBELLWILSON, D YE, T DULK, G LEBLANC, Y GALOPEAU, P GERARD, E LECACHEUX, A AF DEPATER, I HEILES, C WONG, M MADDALENA, RJ BIRD, MK FUNKE, O NEIDHOEFER, J PRICE, RM KESTEVEN, M CALABRETTA, M KLEIN, MJ GULKIS, S BOLTON, SJ FOSTER, RS SUKUMAR, S STROM, RG LEPOOLE, RS SPOELSTRA, T ROBISON, M HUNSTEAD, RW CAMPBELLWILSON, D YE, T DULK, G LEBLANC, Y GALOPEAU, P GERARD, E LECACHEUX, A TI OUTBURST OF JUPITER SYNCHROTRON-RADIATION AFTER THE IMPACT OF COMET SHOEMAKER-LEVY-9 SO SCIENCE LA English DT Article ID RADIO IMAGES AB Jupiter's nonthermal microwave emission, as measured by a global network of 11 radio telescopes, increased dramatically during the Shoemaker-Levy 9 impacts. The increase was wavelength-dependent, varying from similar to 10 percent at 70 to 90 centimeters to similar to 45 percent at 6 and 36 centimeters. The radio spectrum hardened (flattened toward shorter wavelengths) considerably during the week of impacts and continued to harden afterward. After the week of cometary impacts, the flux density began to subside at all wavelengths and was still declining 3 months later. Very Large Array and Australia Telescope images of the brightness distribution showed the enhancement to be localized in longitude and concentrated near the magnetic equator. The evidence therefore suggests that the increase in flux density was caused by a change in the resident particle population, for example, through an energization or spatial redistribution of the emitting particles. C1 NATL RADIO ASTRON OBSERV,GREEN BANK,WV 24944. UNIV BONN,D-53121 BONN,GERMANY. MAX PLANCK INST RADIOASTRON,D-53121 BONN,GERMANY. CSIRO,EPPING,NSW 2121,AUSTRALIA. CALTECH,JET PROP LAB,PASADENA,CA 91109. USN,RES LAB,WASHINGTON,DC 20375. NATL RES COUNCIL CANADA,DOMIN RADIO ASTROPHYS OBSERV,PENTICTON,BC V2A 6K3,CANADA. NETHERLANDS FDN RES ASTRON,7990 AA DWINGELOO,NETHERLANDS. LEIDEN UNIV,2300 RA LEIDEN,NETHERLANDS. NEW MEXICO INST MIN & TECHNOL,SOCORRO,NM 87801. UNIV SYDNEY,SCH PHYS,SYDNEY,NSW 2006,AUSTRALIA. DEPT ASTROPHYS PLANETARY & ATMOSPHER SCI,BOULDER,CO 80309. OBSERV PARIS,F-92195 MEUDON,FRANCE. RP DEPATER, I (reprint author), UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720, USA. NR 31 TC 32 Z9 32 U1 0 U2 1 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 30 PY 1995 VL 268 IS 5219 BP 1879 EP 1883 DI 10.1126/science.11536723 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RF990 UT WOS:A1995RF99000032 PM 11536723 ER PT J AU SADDOW, SE LANG, M DALIBOR, T PENSL, G NEUDECK, PG AF SADDOW, SE LANG, M DALIBOR, T PENSL, G NEUDECK, PG TI THERMAL CAPACITANCE SPECTROSCOPY OF EPITAXIAL 3C AND 6H-SIC PN JUNCTION DIODES GROWN SIDE-BY-SIDE ON A GH-SIC SUBSTRATE SO APPLIED PHYSICS LETTERS LA English DT Article ID CARBIDE; CENTERS C1 UNIV ERLANGEN NURNBERG, INST ANGEW PHYS, D-91058 ERLANGEN, GERMANY. NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. RP SADDOW, SE (reprint author), USA, RES LAB, WEAPONS TECHNOL DIRECTORATE, ADELPHI, MD 20783 USA. NR 16 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 26 PY 1995 VL 66 IS 26 BP 3612 EP 3614 DI 10.1063/1.113804 PG 3 WC Physics, Applied SC Physics GA RE742 UT WOS:A1995RE74200024 ER PT J AU GIRIMAJI, SS ZHOU, Y AF GIRIMAJI, SS ZHOU, Y TI SPECTRUM AND ENERGY-TRANSFER IN STEADY BURGERS TURBULENCE SO PHYSICS LETTERS A LA English DT Article ID ISOTROPIC TURBULENCE; DISSIPATION-RANGE; SCALES AB The spectrum, energy transfer and spectral interactions in steady Burgers turbulence are studied using numerically generated data. The velocity field is initially random and the turbulence is maintained steady by forcing the amplitude of a band of low wavenumbers to be invariant in time, while permitting the phase to change as dictated by the equation. The spectrum, as expected, is very different from that of Navier-Stokes turbulence. It is demonstrated, for the first time. that the far range of the spectrum scales as predicted by Burgers. Despite the difference in their spectra, in matters of the spectral energy transfer and triadic interactions Burgers turbulence is similar to Navier-Stokes turbulence. RP GIRIMAJI, SS (reprint author), NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681, USA. 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 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUN 26 PY 1995 VL 202 IS 4 BP 279 EP 287 DI 10.1016/0375-9601(95)00317-V PG 9 WC Physics, Multidisciplinary SC Physics GA RG329 UT WOS:A1995RG32900007 ER PT J AU GLAZMAN, RE AF GLAZMAN, RE TI A SIMPLE THEORY OF CAPILLARY-GRAVITY WAVE TURBULENCE SO JOURNAL OF FLUID MECHANICS LA English DT Article AB Employing a recently proposed 'multi-wave interaction' theory (Glazman 1992), inertial spectra of capillary-gravity waves are derived. This case is characterized by a rather high degree of nonlinearity and a complicated dispersion law. The absence of scale invariance makes this and some other problems of wave turbulence (e.g. nonlinear inertia-gravity waves) intractable by small-perturbation techniques, even in the weak-turbulence limit. The analytical solution obtained in the present work for an arbitrary degree of nonlinearity is shown to be in reasonable agreement with experimental data. The theory explains the dependence of the wave spectrum on wind input and describes the accelerated roll-off of the spectral density function in the narrow sub-range separating scale-invariant regimes of purely gravity and capillary waves, while the appropriate (long- and short-wave) limits yield power laws corresponding to the Zakharov-Filonenko and Phillips spectra. RP GLAZMAN, RE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 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 JUN 25 PY 1995 VL 293 BP 25 EP 34 DI 10.1017/S0022112095001613 PG 10 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RG541 UT WOS:A1995RG54100002 ER PT J AU LEBOEUF, RL MEHTA, RD AF LEBOEUF, RL MEHTA, RD TI MEASUREMENTS OF SPANWISE SCALE CHANGE IN A FORCED MIXING LAYER SO JOURNAL OF FLUID MECHANICS LA English DT Article ID STREAMWISE VORTICAL STRUCTURES; FREE SHEAR-LAYER; PLANE; EVOLUTION AB Spanwise scale changes of the streamwise vortical structure in a plane forced mixing layer have been investigated through direct measurements. Detailed three-dimensional phase-averaged measurements were obtained of the spanwise and streamwise vorticity in a forced mixing layer undergoing three spanwise roller pairings. A two-stream mixing layer with a velocity ratio (U-2/U-1) of 0.6 and laminar initial boundary layers was generated in a mixing-layer wind tunnel. Acoustic forcing, consisting of a fundamental roll-up frequency and its first, second and third subharmonics, was used to phase-lock the initial development and the first three pairings of the spanwise rollers. Although the overall spanwise scale remained unchanged through the first two roller pairings, some (cyclic) 'readjustment' of the weaker streamwise structures was observed. The overall spanwise scale doubled during the third roller pairing. For the first time, one of the proposed mechanisms for the scale change has been identified and its details measured directly. The weakest (positive) streamwise vortex is split into two and displaced by stronger neighbouring (negative) vortices. These two vortices (of the same sign) then merge together, thus doubling the spanwise scale and circulation of the resulting streamwise vortical structure. C1 STANFORD UNIV, JIAA, DEPT AERONAUT & ASTRONAUT, STANFORD, CA 94305 USA. NASA, AMES RES CTR, FLUID MECH LAB, MOFFETT FIELD, CA 94035 USA. RP LEBOEUF, RL (reprint author), STANFORD UNIV, NASA, AMES RES CTR, CTR TURBULENCE RES, MOFFETT FIELD, CA 94035 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0022-1120 EI 1469-7645 J9 J FLUID MECH JI J. Fluid Mech. PD JUN 25 PY 1995 VL 293 BP 305 EP 319 DI 10.1017/S0022112095001728 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RG541 UT WOS:A1995RG54100013 ER PT J AU MCBEATH, MK SHAFFER, DM KAISER, MK AF MCBEATH, MK SHAFFER, DM KAISER, MK TI PLAY BALL - RESPONSE SO SCIENCE LA English DT Letter C1 NASA,AMES RES CTR,HUMAN SYST TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP MCBEATH, MK (reprint author), KENT STATE UNIV,DEPT PSYCHOL,KENT,OH 44242, USA. RI Shaffer, Dennis/F-5300-2013 NR 0 TC 7 Z9 7 U1 0 U2 2 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 23 PY 1995 VL 268 IS 5218 BP 1683 EP 1685 DI 10.1126/science.268.5218.1683-a PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RE668 UT WOS:A1995RE66800007 PM 17834973 ER PT J AU FRANCISCO, JS SANDER, SP AF FRANCISCO, JS SANDER, SP TI PROTONATED HYDROCHLOROUS ACID (HOCLH+) - MOLECULAR-STRUCTURE, VIBRATIONAL FREQUENCIES, AND PROTON AFFINITY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID EQUILIBRIUM-CONSTANT; ULTRAVIOLET-SPECTRUM; H2O; CI C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 19 TC 14 Z9 14 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 22 PY 1995 VL 102 IS 24 BP 9615 EP 9618 DI 10.1063/1.468778 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RD332 UT WOS:A1995RD33200020 ER PT J AU JOBLIN, C SALAMA, F ALLAMANDOLA, L AF JOBLIN, C SALAMA, F ALLAMANDOLA, L TI PHOTOINDUCED FLUORESCENCE FROM THE PERYLENE CATION ISOLATED IN NE AND AR MATRICES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID OPTICAL-EMISSION BANDS; SPECTRA RP JOBLIN, C (reprint author), NASA,AMES RES CTR,MS 245-6,MOFFETT FIELD,CA 94035, USA. OI Salama, Farid/0000-0002-6064-4401 NR 13 TC 26 Z9 26 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 22 PY 1995 VL 102 IS 24 BP 9743 EP 9745 DI 10.1063/1.468793 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RD332 UT WOS:A1995RD33200035 ER PT J AU HOGE, FE SWIFT, R YUNGEL, J AF HOGE, FE SWIFT, R YUNGEL, J TI OCEANIC RADIANCE MODEL DEVELOPMENT AND VALIDATION - APPLICATION OF AIRBORNE ACTIVE-PASSIVE OCEAN COLOR SPECTRAL MEASUREMENTS SO APPLIED OPTICS LA English DT Article DE OCEAN COLOR; RADIANCE MODEL; LIDAR; REMOTE SENSING; INHERENT OPTICAL PROPERTIES ID DISSOLVED ORGANIC-MATTER; WARM CORE RING; CORRELATION SPECTROSCOPY; OPTICAL CLASSIFICATION; CHLOROPHYLL PIGMENT; REFLECTANCE MODEL; SOLAR IRRADIANCE; ATLANTIC BIGHT; NATURAL-WATERS; PHYTOPLANKTON AB It is shown that airborne active-passive (laser-solar) ocean color data can be used to develop and validate oceanic radiance models. The two principal inputs to the oceanic radiance model, chlorophyll pigment and incident solar irradiance, are obtained from a nadir-viewing laser-induced fluorescence spectrometer and a zenith-viewing radiometer, respectively. The computed water-leaving radiances are validated by comparison with the calibrated output of a separate nadir-viewing radiometer subsystem. In the North Atlantic Ocean, the calculated and the observed airborne radiances are found to compare very favorably for the 443-, 520-, and 550-nm wavelengths over an similar to 170-km flight track east of St. John's, Newfoundland. The results further suggest that the semianalytical radiance model of ocean color, the airborne active (laser) fluorescence spectrometer, and the passive (solar) radiometric instrumentation are all remarkably precise. C1 EG & G INC,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. RP HOGE, FE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,WALLOP FLIGHT FACIL,WALLOPS ISL,VA 23337, USA. NR 48 TC 11 Z9 11 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 1995 VL 34 IS 18 BP 3468 EP 3476 PG 9 WC Optics SC Optics GA RC496 UT WOS:A1995RC49600040 PM 21052162 ER PT J AU CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE AF CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE TI PHASE-TRANSITION THEORY OF INSTABILITIES .1. 2ND-HARMONIC INSTABILITY AND BIFURCATION POINTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, GENERAL; GALAXIES, FORMATION; HYDRODYNAMICS; INSTABILITIES; STARS, FORMATION ID RIEMANN DISKS; GALACTIC BAR; EQUILIBRIUM; STABILITY; OSCILLATIONS; GALAXIES; STARS AB We use a free-energy minimization approach to describe in simple and clear physical terms the secular and dynamical instabilities as well as the bifurcations along well-known sequences of rotating, self-gravitating fluid and stellar systems such as the Maclaurin spheroids, the Jacobi, Dedekind, and Riemann ellipsoids, and the fluid/stellar disks. Our approach stems from the Ginzburg-Landau theory of phase transitions. In this paper, we focus on the Maclaurin sequence of oblate spheroidal equilibria and on the effects of nonaxisymmetric, second-harmonic disturbances. The free-energy approach has been pioneered in astrophysics by Bertin and Radicati (1976) who showed that the secular instability beyond the Maclaurin-Jacobi bifurcation can be interpreted as a second-order phase transition. We show that second-order phase transitions appear on the Maclaurin sequence also at the points of dynamical instability (bifurcation of the x = +1 self-adjoint Riemann sequence) and of bifurcation of the Dedekind sequence. The distinguishing characteristic of each second-order phase transition is the conservation/nonconservation of an integral of motion (a ''conserved/nonconserved current'') which, in effect, determines uniquely whether the transition appears or not. The secular instability beyond the Jacobi bifurcation appears only if circulation is not conserved. The secular instability at the Dedekind bifurcation appears only if angular momentum is not conserved. We show by an explicit calculation that, in the presence of dissipation agents that violate one or the other conservation law, the global minimum of the free-energy function beyond the onset of secular instability belongs to the Jacobi and to the Dedekind sequence, respectively. In the case of a ''perfect'' fluid which conserves both circulation and angular momentum, the ''secular'' phase transitions are no longer realized and the Jacobi/Dedekind bifurcation point becomes irrelevant. The Maclaurin spheroid remains at the global minimum of the free-energy function up to the bifurcation point of the x = +1 Riemann sequence. The x = +1 equilibria have lower free energy than the corresponding Maclaurin spheroids for the same values of angular momentum and circulation. Thus, a ''dynamical'' second-order phase transition is allowed to take place beyond this bifurcation point. This phase transition brings the spheroid, now sitting at a saddle point of the free-energy function, to the new global minimum on the x = +1 Riemann sequence. Circulation is not conserved in stellar systems because the stress-tenser gradient terms that appear in the Jeans equations of motion include ''viscosity-like'' off-diagonal terms of the same order of magnitude as the conventional ''pressure'' gradient terms. For this reason, globally unstable axisymmetric stellar systems evolve toward the ''stellar'' Jacobi sequence on dynamical timescales. This explains why the Jacobi bifurcation is a point of dynamical instability in stellar systems but only a point of secular instability in viscous fluids. The second-order phase transitions on the Maclaurin sequence are discussed in relation to the dynamical instability of stellar systems, the lambda-transition of liquid He-4, the second-order phase transition in superconductivity, and the mechanism of spontaneous symmetry breaking. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ACAD SCI GOTTINGEN,GOTTINGEN,GERMANY. UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. RP CHRISTODOULOU, DM (reprint author), UNIV VIRGINIA,VIRGINIA INST THEORET ASTRON,DEPT ASTRON,POB 3818,CHARLOTTESVILLE,VA 22903, USA. NR 44 TC 16 Z9 16 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1995 VL 446 IS 2 BP 472 EP 484 DI 10.1086/175806 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500003 ER PT J AU CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE AF CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE TI PHASE-TRANSITION THEORY OF INSTABILITIES .2. 4TH-HARMONIC BIFURCATIONS AND LAMBDA-TRANSITIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, KINEMATICS AND DYNAMICS; GALAXIES, STRUCTURE; INSTABILITIES; STARS, FORMATION; STARS, ROTATION ID RAPIDLY ROTATING POLYTROPES; VERSATILE METHOD; STAR FORMATION; CLOUDS; FRAGMENTATION; EQUILIBRIUM; STABILITY; COLLAPSE; FISSION; FLUID AB We use a free-energy minimization approach to describe in simple and clear physical terms the secular and dynamical instabilities as well as the bifurcations along equilibrium sequences of rotating, self-gravitating fluid systems. Our approach is fully nonlinear and stems from the Ginzburg-Landau theory of phase transitions. In this paper, we examine fourth-harmonic axisymmetric disturbances in Maclaurin spheroids and fourth-harmonic nonaxisymmetric disturbances in Jacobi ellipsoids. These two cases are very similar in the framework of phase transitions. It has been conjectured (Hachisu and Eriguchi 1983) that third-order phase transitions, manifested as smooth bifurcations in the angular momentum-rotation frequency plane, may occur on the Maclaurin sequence at the bifurcation point of the axisymmetric one-ring sequence and on the Jacobi sequence at the bifurcation point of the dumbbell-binary sequence. We show that these transitions are forbidden when viscosity maintains uniform rotation. The uniformly rotating one-ring/dumbbell equilibria close to each bifurcation point and their neighboring uniformly rotating nonequilibrium states have higher free energies than the Maclaurin/Jacobi equilibria of the same mass and angular momentum. These high-energy states act as free-energy barriers preventing the transition of spheroids/ellipsoids from their local minima to the free-energy minima that exist on the low rotation frequency branch of the one-ring/binary sequence. At a critical point, the two minima of the free-energy function are equal, signaling the appearance of a first-order phase transition. This transition can take place beyond the critical point only nonlinearly if the applied perturbations contribute enough energy to send the system over the top of the barrier (and if, in addition, viscosity maintains uniform rotation). In the angular momentum-rotation frequency plane, the one-ring and dumbbell-binary sequences have the shape of an ''inverted S'' and two corresponding turning points each. Because of this shape, the free-energy barrier disappears suddenly past the higher turning point, leaving the spheroid/ellipsoid on a saddle point but also causing a ''catastrophe'' by permitting a ''secular'' transition toward a one-ring/binary minimum energy state. This transition appears as a typical second-order phase transition, although there is no associated sequence bifurcating at the transition point (cf. Christodoulou et al. 1995a). Irrespective of whether a nonlinear first-order phase transition occurs between the critical point and the higher turning point or an apparent second-order phase transition occurs beyond the higher turning point, the result is fission (i.e., ''spontaneous breaking'' of the topology) of the original object on a secular timescale: the Maclaurin spheroid becomes a uniformly rotating axisymmetric torus, and the Jacobi ellipsoid becomes a binary. The presence of viscosity is crucial since angular momentum needs to be redistributed for uniform rotation to be maintained. We strongly suspect that the ''secular catastrophe'' is the dynamical analog of the notorious A-transition of liquid He-4 because it appears as a ''second-order'' phase transition with infinite ''specific heat'' at the point where the free-energy barrier disappears suddenly. This transition is not an elementary catastrophe. In contrast to this case, a ''dynamical catastrophe'' takes place from the bifurcation point to the lower branch of the Maclaurin toroid sequence because all conservation laws are automatically satisfied between the two equilibrium states. Furthermore, the free-energy barrier disappears gradually, and this transition is part of the elementary cusp catastrophe. This type of ''lambda-transition'' is the dynamical analog of the Bose-Einstein condensation of an ideal Bose gas. The phase transitions of the dynamical systems are briefly discussed in relation to previous numerical simulations of the formation and evolution of protostellar systems. Some technical discussions concerning related results obtained from linear stability analyses, the breaking of topology, and the nonlinear theories of structural stability and catastrophic morphogenesis are included in an appendix. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ACAD SCI GOTTINGEN,GOTTINGEN,GERMANY. UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. RP CHRISTODOULOU, DM (reprint author), UNIV VIRGINIA,VIRGINIA INST THEORET ASTRON,DEPT ASTRON,POB 3818,CHARLOTTESVILLE,VA 22903, USA. NR 68 TC 7 Z9 7 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1995 VL 446 IS 2 BP 485 EP 499 DI 10.1086/175807 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500004 ER PT J AU CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE AF CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE TI PHASE-TRANSITION THEORY OF INSTABILITIES .3. THE 3RD-HARMONIC BIFURCATION ON THE JACOBI SEQUENCE AND THE FISSION PROBLEM SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, GENERAL; GALAXIES, FORMATION; HYDRODYNAMICS; INSTABILITIES; STARS, FORMATION ID ROTATING POLYTROPES; STABILITY; EQUILIBRIUM; FLUID; SYSTEM; MODELS; STARS AB In Christodoulou et al. (1995a, b, hereafter Papers I and II), we used a free-energy minimization approach that stems from the Ginzburg-Landau theory of phase transitions to describe in simple and clear physical terms the secular and dynamical instabilities as well as the bifurcations along equilibrium sequences of rotating, self-gravitating fluid systems. Based on the physical picture that emerged from this method, we investigate here the secular and dynamical third-harmonic instabilities that are presumed to appear first and at the same point on the Jacobi sequence of incompressible zero-vorticity ellipsoids. Poincare (1885) found a bifurcation point on the Jacobi sequence where a third-harmonic mode of oscillation becomes neutral. A sequence of pear-shaped equilibria branches off at this point, but this result does not necessarily imply secular instability. The total energies of the pear-shaped objects must also be lower than those of the corresponding Jacobi ellipsoids with the same angular momentum. This condition is not met if the pear-shaped objects are assumed to rotate uniformly. Near the bifurcation point, such uniformly rotating pear-shaped objects stand at higher energies relative to the Jacobi sequence. (e.g., Jeans 1929). This result implies secular instability in pear-shaped objects and a return to the ellipsoidal form. Therefore, assuming that uniform rotation is maintained by viscosity, the Jacobi ellipsoids continue to remain secularly stable (and thus dynamically stable as well) past the third-harmonic bifurcation point. Cartan (1924) found that dynamical third-harmonic instability also sets in at the Jacobi-pear bifurcation. This result is irrelevant in the case of uniform rotation because the perturbations used in Cartan's analysis carry vorticity and, by Kelvin's theorem of irrotational motion, cannot cause instability. Such vortical perturbations cause differential rotation that cannot be damped since viscosity has been assumed absent from Cartan's equations. Thus, Cartan's instability leads to differentially rotating objects and not to uniformly rotating pear-shaped vortical modes disappear in the presence of any amount of viscosity (cf. Narayan, Goldreich, and Goodman 1987). The fourth-harmonic bifurcation on the Jacobi sequence leads to the dumbbell equilibria that also have initially higher total energies (Paper II). From these considerations, we deduce that a Jacobi ellipsoid can evolve away from the sequence only via a discontinuous lambda-transition (Paper II), provided there exists a branch of lower energy and broken topology in any of the known bifurcating sequences. The breaking of topology circumvents Kelvin's theorem and allows a zero-vorticity Jacobi ellipsoid to abandon the sequence. A pear-shaped sequence has been obtained numerically by Eriguchi, Hachisu, and Sugimoto (1982). Using their results, we demonstrate that the entire sequence exists at higher energies and at higher rotation frequencies relative to the Jacobi sequence. These results were expected since they were predicted by the classical analytical calculations of Jeans (1929). Furthermore, the computed pear-shaped sequence terminates prematurely above the Jacobi sequence due to equatorial mass shedding and thus has no lower energy branch of broken topology. Therefore, there exists no lambda-transition associated with the pear-shaped sequence. In this case, the first lambda-transition on the Jacobi sequence is of type 2 and appears past the higher turning point of the dumbbell-binary sequence. This transition has been described in Paper II. The Jacobi ellipsoid undergoes fission on a secular timescale arid a short-period binary is produced. The classical fission hypothesis of binary star formation of Poincare and Darwin is thus feasible. In all stages, evolution proceeds quasistatically, and thus the resulting fission is retarded just as was anticipated by Tassoul (1978). Modern approaches to the fission problem (Lebovitz 1972; Ostriker and Bodenheimer 1973), involving perfect fluid masses, are also discussed briefly in the context of phase transitions. The above conclusions can be strengthened by a more accurate computation of the pear-shaped sequence and by hydrodynamical simulations of viscous Jacobi ellipsoids prior to and past the lambda-point of the dumbbell-binary sequence. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ACAD SCI GOTTINGEN,GOTTINGEN,GERMANY. UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. RP CHRISTODOULOU, DM (reprint author), UNIV VIRGINIA,VIRGINIA INST THEORET ASTRON,DEPT ASTRON,POB 3818,CHARLOTTESVILLE,VA 22903, USA. NR 48 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1995 VL 446 IS 2 BP 500 EP 509 DI 10.1086/175808 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500005 ER PT J AU CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE AF CHRISTODOULOU, DM KAZANAS, D SHLOSMAN, I TOHLINE, JE TI PHASE-TRANSITION THEORY OF INSTABILITIES .4. CRITICAL-POINTS ON THE MACLAURIN SEQUENCE AND NONLINEAR FISSION PROCESSES SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, GENERAL; GALAXIES, FORMATION; HYDRODYNAMICS; INSTABILITIES; STARS, FORMATION ID SELF-GRAVITATING ANNULI; ACCRETION TORI; STABILITY; FLUID; FRAGMENTATION; EQUILIBRIUM; STAR AB We use a free-energy minimization approach to describe in simple and clear physical terms the secular and dynamical instabilities as well as the bifurcations along equilibrium sequences of rotating, self-gravitating fluid systems. Our approach is fully nonlinear and stems from the Ginzburg-Landau theory of phase transitions. In the final paper of this series, we examine higher than second-harmonic disturbances applied to Maclaurin spheroids, the corresponding bifurcating sequences, and their relation to nonlinear fission processes. The triangle and ammonite sequences bifurcate from the two third-harmonic neutral points on the Maclaurin sequence, while the square and one-ring sequences bifurcate from two of the three known fourth-harmonic neutral points. The one-ring sequence has been analyzed in Christodoulou et al. (1995b). In the other three cases, secular instability does not set in at the corresponding bifurcation points because the sequences stand and terminate at higher energies relative to the Maclaurin sequence. Consequently, an anticipated (numerically unresolved) third-order phase transition at the ammonite bifurcation and numerically resolved second-order phase transitions at the triangle and square bifurcations are strictly forbidden. Furthermore, the ammonite sequence exists at higher rotation frequencies as well and is similar in every respect to the pear-shaped sequence that has been analyzed in Christodoulou et al. (1995c). There is no known bifurcating sequence at the point of third-harmonic dynamical instability. This point represents a discontinuous lambda-transition of type 3 that brings a Maclaurin spheroid on a dynamical timescale directly to the binary sequence while the original symmetry and topology are broken in series. The remaining fourth-harmonic neutral point also appears to be related to a type-3 lambda-transition which however takes place from the lower turning point of the one-ring sequence toward the starting point and then on toward the stable branch of the three-fluid-body (triple) sequence. A third type-3 lambda-transition, taking place from the one-ring sequence toward the starting point and then on toward the stable branch of the four-fluid-body (quadruple) sequence, is also discussed. The two-ring sequence bifurcates from the axisymmetric sixth-harmonic neutral point on the Maclaurin sequence also toward higher energies initially but eventually turns around and proceeds to lower energies relative to the Maclaurin sequence. The point where the two sequences have equal energies represents a fourth type of lambda-transition which is not preceded by a first-order phase transition. This type-4 lambda-transition results in double fission on a secular timescale: a Maclaurin spheroid breaks into two coaxial axisymmetric tori that rotate uniformly and with the same frequency. Finally, our nonlinear approach easily identifies resonances between the Maclaurin sequence and various multi-fluid-body sequences that cannot be detected by linear stability analyses. Resonances appear as first-order phase transitions at points where the energies of the two sequences are nearly equal but the lower energy state belongs to one of the multi-fluid-body sequences. Three nonlinear resonances leading to the turning points of the binary, triple, and quadruple sequences are described. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. ACAD SCI GOTTINGEN,GOTTINGEN,GERMANY. UNIV KENTUCKY,DEPT PHYS & ASTRON,LEXINGTON,KY 40506. LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. RP CHRISTODOULOU, DM (reprint author), UNIV VIRGINIA,VIRGINIA INST THEORET ASTRON,DEPT ASTRON,POB 3818,CHARLOTTESVILLE,VA 22903, USA. NR 39 TC 3 Z9 3 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1995 VL 446 IS 2 BP 510 EP 520 DI 10.1086/175809 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500006 ER PT J AU VERTER, F HODGE, P AF VERTER, F HODGE, P TI GR-8 - CO-TO-H-2 CONVERSION FACTOR AT EXTREMELY LOW METALLICITY SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, ISM; GALAXIES, INDIVIDUAL; (GR 8); ISM, MOLECULES ID DWARF IRREGULAR GALAXIES; SMALL MAGELLANIC CLOUD; SEST KEY PROGRAM; NEUTRAL HYDROGEN OBSERVATIONS; H-II REGIONS; MOLECULAR CLOUDS; STAR-FORMATION; CARBON-MONOXIDE; CO OBSERVATIONS; GAS AB We have obtained CO(2-1) upper limits of 6 and 7 mK toward two positions in the extremely metal poor dwarf irregular galaxy GR 8. The H alpha emission of GR 8 shows active star formation which requires that the galaxy contain at least 1.5 x 10(4) M. of molecular gas. Our inability to detect CO emission implies that the CO-to-H-2 conversion factor in the vicinity of the dominant star-formation region is at least 80 x 10(20) molecules cm(-2) (K km s(-1))(-1). We compare GR 8 to all other irregular galaxies for which N(H-2)/W-CO has been measured; we confirm that the CO-to-H-2 conversion factor increases with decreasing metallicity or with increasing linear scale of the observations. C1 UNIV WASHINGTON,DEPT ASTRON,SEATTLE,WA 98195. RP VERTER, F (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MC 685,GREENBELT,MD 20771, USA. NR 66 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 JUN 20 PY 1995 VL 446 IS 2 BP 616 EP 621 DI 10.1086/175821 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500018 ER PT J AU HILL, RS CHENG, KP BOHLIN, RC OCONNELL, RW ROBERTS, MS SMITH, AM STECHER, TP AF HILL, RS CHENG, KP BOHLIN, RC OCONNELL, RW ROBERTS, MS SMITH, AM STECHER, TP TI UIT AND OPTICAL IMAGERY OF LARGE MAGELLANIC CLOUD ASSOCIATIONS LH-52 AND LH-53 - AGES AND INITIAL MASS FUNCTION SLOPES SO ASTROPHYSICAL JOURNAL LA English DT Article DE DUST, EXTINCTION; MAGELLANIC CLOUDS; OPEN CLUSTERS AND ASSOCIATIONS, INDIVIDUAL (LH 52, LH 53); STARS, LUMINOSITY FUNCTION, MASS FUNCTION; ULTRAVIOLET, STARS ID SUPERNOVA REMNANT N49; STELLAR PHOTOMETRY; STAR FORMATION; CYGNUS LOOP; ULTRAVIOLET; EXTINCTION; EVOLUTION; TELESCOPE; EMISSION; MODELS AB A 40' field including the stellar associations LH 52 and LH 53 and the supernova remnant N49 in the Large Magellanic Cloud was observed by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 Space Shuttle mission in 1990 December. The image in the 162 nm bandpass is discussed together with groundbased BV data on subfields containing LH 52 and LH 53. Point-spread function photometry in the 162 nm, B, and V bands is presented in the form of color-magnitude diagrams and two-color diagrams, which are compared with stellar models. The far-ultraviolet extinction curve of the dust in LH 52 is unusually steep for the LMC. The most probable age of both associations is similar to 10 Myr, which constrains the scenario for the evolution of the supergiant H alpha shell LMC 4 by stochastic self-propagated star formation. The initial mass function (IMF) slope for LH 52 is Gamma approximate to -1, in agreement with previous work, and the slope for LH 53, which is less densely populated, is Gamma approximate to -2. A similar relationship between surface density of stars and IMF slope is reported for a UIT held near 30 Dor. The ultraviolet morphology of N49, which is contained in LH 53, is dominated by two bright features that straddle an X-ray bright spot, consistent with an encounter between the blast wave and a cloud. The estimated age of similar to 10 Myr for LH 53 implies an initial mass of similar to 20 M. for the N49 progenitor star. C1 SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. UNIV VIRGINIA, CHARLOTTESVILLE, VA 22903 USA. NATL RADIO ASTRON OBSERV, CHARLOTTESVILLE, VA 22903 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP HILL, RS (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX CORP, CODE 681, GREENBELT, MD 20071 USA. NR 39 TC 38 Z9 38 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 JUN 20 PY 1995 VL 446 IS 2 BP 622 EP 636 DI 10.1086/175822 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500019 ER PT J AU SWARTZ, DA SUTHERLAND, PG HARKNESS, RP AF SWARTZ, DA SUTHERLAND, PG HARKNESS, RP TI GAMMA-RAY TRANSFER AND ENERGY DEPOSITION IN SUPERNOVAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, THEORY; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES; RADIATIVE TRANSFER; SUPERNOVAE, GENERAL ID I SUPERNOVAE; SN 1987A; MODELS; EMISSION; SN-1987A; NOVAE AB Solutions to the energy-independent (gray) radiative transfer equations are compared to results of Monte Carlo simulations of the Ni-56 and Co-56 radioactive decay gamma-ray energy deposition in supernovae. The comparison shows that an effective, purely absorptive, gray opacity, kappa(gamma), similar to (0.06 +/- 0.01)Y-e cm(2) g(-1), where Y-e is the total number of electrons per baryon, accurately describes the interaction of gamma-rays with the cool supernova gas and the local gamma-ray energy deposition within the gas. The nature of the gamma-ray interaction process (dominated by Compton scattering in the relativistic regime) creates a weak dependence of kappa(gamma) on the optical thickness of the (spherically symmetric) supernova atmosphere: The maximum value of kappa(gamma) applies during optically thick conditions when individual gamma-rays undergo multiple scattering encounters and the lower bound is reached at the phase characterized by a total Thomson optical depth to the center of the atmosphere tau(e) less than or similar to 1. However, the constant asymptotic value, kappa(gamma) = 0.050Y(e) cm(2) g(-1), reproduces the thermal light curve due to gamma-ray deposition for Type Ia supernova models to within 10% for the epoch from maximum light to t = 1200 days. Our results quantitatively confirm that the quick and efficient solution to the gray transfer problem provides an accurate representation of gamma-ray energy deposition for a broad range of supernova conditions. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ASTROPHYS BRANCH,HUNTSVILLE,AL 35812. MCMASTER UNIV,DEPT PHYS & ASTRON,HAMILTON,ON L8S 4M1,CANADA. UNIV TEXAS,CTR HIGH PERFORMANCE COMP,BALCONES RES CTR,AUSTIN,TX 78758. NR 34 TC 49 Z9 49 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 20 PY 1995 VL 446 IS 2 BP 766 EP 774 DI 10.1086/175834 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC755 UT WOS:A1995RC75500031 ER PT J AU FINGER, MH WILSON, RB PENDLETON, GN RUBIN, BC AF FINGER, MH WILSON, RB PENDLETON, GN RUBIN, BC TI DISCOVERY OF THE 18.7-SECOND ACCRETING X-RAY PULSAR GRO-J1948+32 SO ASTROPHYSICAL JOURNAL LA English DT Article DE PULSARS, INDIVIDUAL, (GRO J1948 + 32); PULSARS, INDIVIDUAL, (GRO J2014 + 34); X-RAYS, STARS ID PARAMETER-ESTIMATION; ASTRONOMY AB We have detected an 18.7 s accreting X-ray pulsar in the Cygnus region, using the BATSE large-area detectors on the Compton Gamma Ray Observatory. GRO J1948 + 32 has been localized to within 10 deg(2) using a method we developed for positioning weak pulsed sources with BATSE. During the 33 day outburst, the phase-averaged 20-75 keV pulsed flux rose from 25 mCrab to 50 mCrab over 10 days and then decayed below our detection threshold over nearly 25 days. A photon spectral index of gamma = 2.65 +/- 0.15 (assuming photon flux density dN/dE proportional to E(-gamma)) was measured during a bright interval. The observed modulation of the neutron star's pulse frequency is suggestive of orbital variation over less than one orbit cycle. Assuming a constant spin frequency derivative over the outburst, we can place the following individual 95% confidence limits on each of the pulsar parameters: orbital period 35(d) < P-orb < 70(d); orbital radius 75 lt-sec < a(x) sin i < 300 lt-sec, eccentricity e < 0.25, spin frequency derivative 5 x 10(-13) Hz s(-1) < v < 2.5 x 10(-11) Hz s(-1), X-ray mass function 0.5 M. + 5 parts per thousand) and extreme variations (up to 10 parts per thousand) in delta(13)C evident in Neoproterozoic successions of similar thickness and environmental setting. Hence, in contrast to the Neoproterozoic, the global rate of organic carbon burial was probably fairly constant during deposition of the Bangemall Group, and perhaps generally during the Mesoproterozoic, as was the redox state of the atmosphere and hydrosphere. C1 HARVARD UNIV,BOT MUSEUM,CAMBRIDGE,MA 02138. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. OI Buick, Roger/0000-0003-0139-1659 NR 53 TC 88 Z9 92 U1 4 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JUN 20 PY 1995 VL 123 IS 1-4 BP 153 EP 171 DI 10.1016/0009-2541(95)00049-R PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RL564 UT WOS:A1995RL56400009 PM 11540130 ER PT J AU WILD, JD GELMAN, ME MILLER, AJ CHANIN, ML HAUCHECORNE, A KECKHUT, P FARLEY, R DAO, PD MERIWETHER, JW GOBBI, GP CONGEDUTI, F ADRIANI, A MCDERMID, IS MCGEE, TJ FISHBEIN, EF AF WILD, JD GELMAN, ME MILLER, AJ CHANIN, ML HAUCHECORNE, A KECKHUT, P FARLEY, R DAO, PD MERIWETHER, JW GOBBI, GP CONGEDUTI, F ADRIANI, A MCDERMID, IS MCGEE, TJ FISHBEIN, EF TI COMPARISON OF STRATOSPHERIC TEMPERATURES FROM SEVERAL LIDARS, USING NATIONAL-METEOROLOGICAL-CENTER AND MICROWAVE LIMB SOUNDER DATA AS TRANSFER REFERENCES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE ATMOSPHERE; RAYLEIGH LIDAR; RAMAN LIDAR AB Stratospheric temperatures derived from five different lidars are compared. Although the lidars are in five separate geographic locations, the evaluation is accomplished by comparing each of the sets of lidar data taken over the course of a year (1991-1992) with temperatures interpolated to each location from daily global temperature analyses from the National Meteorological Center (NMC). Average differences between the lidars and NMC temperatures vary for the different lidars by up to 6.7 K. Part of this large average temperature difference is shown to be due to the real temperature variation throughout the day, and the different times of observation of the NMC data and each of the lidar systems. Microwave limb sounder (MLS) data from the upper atmosphere research satellite are used to model the diurnal and semidiurnal variations in temperature for each lidar location, for each season. After adjusting for the temperature changes caused by variations in observation time, average temperature differences are reduced among four of the five lidars, compared with the NMC temperatures, but still vary by as much as 3.9 K at stratospheric altitudes between 30 and 45 km. Results of direct comparisons at two permanent lidar sites with a mobile lidar show that sometimes agreement within 1 to 2 K is achieved, but for other cases, larger average differences are seen. Since the precision of lidar temperatures has been estimated to be better than 1 K, further research is needed to reconcile this small expected error with the larger average differences deduced here using measurements made under operational conditions. C1 CNR, IST FIS ATMOSFERA, I-00044 FRASCATI, ITALY. CNRS, SERV AERON, F-91371 VERRIERES LE BUISSON, FRANCE. USAF, PHILLIPS LAB, GEOPHYS DIRECTORATE, BEDFORD, MA 01731 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. JET PROP LAB, WRIGHTWOOD, CA 92397 USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RES & DATA SYST CORP, GREENBELT, MD USA. RP WILD, JD (reprint author), NOAA, NATL WEATHER SERV, NATL METEOROL CTR, CTR CLIMATE ANAL, WASHINGTON, DC 20233 USA. RI Hauchecorne, Alain/A-8489-2013; McGee, Thomas/G-4951-2013 NR 25 TC 21 Z9 21 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11105 EP 11111 DI 10.1029/95JD00631 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100004 ER PT J AU HUDSON, RD KIM, JH THOMPSON, AM AF HUDSON, RD KIM, JH THOMPSON, AM TI ON THE DERIVATION OF TROPOSPHERIC COLUMN OZONE FROM RADIANCES MEASURED BY THE TOTAL OZONE MAPPING SPECTROMETER SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE DATA; TROPICS AB We have developed a new algorithm to retrieve tropospheric column ozone on a daily basis directly from the measured total ozone mapping spectrometer (TOMS) albedos at a spatial resolution of about 50 km. This new algorithm is applied to the retrieval of tropospheric ozone over the region bounded by 20 degrees W and 60 degrees E longitude and 20 degrees S and 0 degrees S latitude during the 1989 biomass burning season when tropospheric ozone approaches 20% of total ozone. We find that for the conditions of high tropospheric ozone during biomass burning, the archived TOMS data underestimates total ozone over cloud free regions and overestimates ozone over the marine stratocumulus cloud off the west coast of Africa. This error can be as high as 15 Dobson units. Thus previous methods which derive tropospheric ozone from the TOMS archived ozone data are subject to error. Details of the algorithm and an analysis of the expected error are presented. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP HUDSON, RD (reprint author), UNIV MARYLAND, DEPT METEOROL, 2213 COMP & SPACE SCI BLDG, COLLEGE PK, MD 20742 USA. RI Hudson, Robert/F-4506-2010; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 21 TC 49 Z9 49 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11137 EP 11145 DI 10.1029/94JD02435 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100006 ER PT J AU BORRMANN, S DYE, JE BAUMGARDNER, D PROFFITT, MH MARGITAN, JJ WILSON, JC JONSSON, HH BROCK, CA LOEWENSTEIN, M PODOLSKE, JR FERRY, GV AF BORRMANN, S DYE, JE BAUMGARDNER, D PROFFITT, MH MARGITAN, JJ WILSON, JC JONSSON, HH BROCK, CA LOEWENSTEIN, M PODOLSKE, JR FERRY, GV TI AEROSOLS AS DYNAMICAL TRACERS IN THE LOWER STRATOSPHERE - OZONE VERSUS AEROSOL CORRELATION AFTER THE MOUNT-PINATUBO ERUPTION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR VORTEX; NITROUS-OXIDE; AASE-II; SULFATE AEROSOL; EXPEDITION; HOLE; DENITRIFICATION; MORPHOLOGY; WINTER; LIDAR AB Stratospheric in situ aerosol and ozone measurements aboard the NASA-operated ER-2 high-altitude research aircraft from August 1991 to May 1993 provide an opportunity to document the temporal evolution of the correlation between the stratospheric aerosol and the ozone from shortly after the Mount Pinatubo eruption until almost two years later. The observations show that at midlatitudes a linear relationship evolves between aerosol surface (or number) mixing ratios and ozone at altitudes ranging from slightly above the tropopause to 14-16 km. This correlation is linear for values of ozone from 200 to 1300 parts per billion by volume and for potential temperatures between 310 K and 467 K. The linear correlation persisted from late December 1991 until early March 1992 but degraded by October 1992. C1 NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. NOAA, AERON LAB, BOULDER, CO 80303 USA. UNIV COLORADO, CIRES, BOULDER, CO 80309 USA. CALTECH, JET PROP LAB, PASADENA, CA USA. UNIV DENVER, DENVER, CO USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP BORRMANN, S (reprint author), UNIV MAINZ, INST ATMOSPHER PHYS, BECHERWEG 21, D-55099 MAINZ, GERMANY. RI Borrmann, Stephan/E-3868-2010; Brock, Charles/G-3406-2011 OI Brock, Charles/0000-0002-4033-4668 NR 32 TC 12 Z9 12 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11147 EP 11156 DI 10.1029/95JD00016 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100007 ER PT J AU SISKIND, DE CONNOR, BJ ECKMAN, RS REMSBERG, EE TSOU, JJ PARRISH, A AF SISKIND, DE CONNOR, BJ ECKMAN, RS REMSBERG, EE TSOU, JJ PARRISH, A TI AN INTERCOMPARISON OF MODEL OZONE DEFICITS IN THE UPPER-STRATOSPHERE AND MESOSPHERE FROM 2 DATA SETS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GRAVITY-WAVES; PHOTOCHEMISTRY; N2O AB We have compared a diurnal photochemical model of ozone with nighttime data from the limb infrared monitor of the stratosphere (LIMS) and ground-based microwave observations. Consistent with previous studies, the model underpredicts the observations by about 10-30%. This agreement is strong confirmation that the model ozone deficit is not simply an artifact of observational error since it is unlikely to occur for two completely different ozone data sets. We have also examined dhe seasonal, altitudinal, and diurnal morphology of the ozone deficit. Both comparisons show a deficit that peaks in the upper stratosphere (2-3 mbar) and goes through a minimum in the lower mesosphere from 1.0 to 0.4 mbar. At lower pressures (< 0.2 mbar) the deficit appears to increase again. The seasonal variation of the deficit is less consistent. The deficit kith respect to the LIMS data is least in winter while with respect to the microwave data, the deficit shows little seasonal variation. Finally, the night-to-day ratio in our model is iii generally good agreement with that seen in the microwave experiment. Increasing the rate coefficient for the reaction O + O-2 + M --> O-3 + M improves the fit, while a very large (50%) decrease in the HOx catalytic cycle is not consistent with our observations. Increasing the atomic oxygen recombination rate also improves the overall agreement with both data sets; however, a residual discrepancy still remains. There appears to be no single chemical parameter which, when modified, can simultaneously resolve both the stratospheric and mesospheric ozone deficits. C1 NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. UNIV MASSACHUSETTS, AMHERST, MA 01003 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23666 USA. MILLITECH CORP, DEERFIELD, MA USA. RP SISKIND, DE (reprint author), USN, RES LAB, EO HULBURT CTR SPACE RES, CODE 7641, 4555 OVERLOOK AVE SW, WASHINGTON, DC 20375 USA. NR 45 TC 48 Z9 48 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11191 EP 11201 DI 10.1029/95JD00366 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100012 ER PT J AU JACKMAN, CH CERNIGLIA, MC NIELSEN, JE ALLEN, DJ ZAWODNY, JM MCPETERS, RD DOUGLASS, AR ROSENFIELD, JE ROOD, RB AF JACKMAN, CH CERNIGLIA, MC NIELSEN, JE ALLEN, DJ ZAWODNY, JM MCPETERS, RD DOUGLASS, AR ROSENFIELD, JE ROOD, RB TI 2-DIMENSIONAL AND 3-DIMENSIONAL MODEL SIMULATIONS, MEASUREMENTS, AND INTERPRETATION OF THE INFLUENCE OF THE OCTOBER 1989 SOLAR PROTON EVENTS ON THE MIDDLE ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HETEROGENEOUS CHEMISTRY; STRATOSPHERIC OZONE; 2-DIMENSIONAL MODEL; PARTICLE EVENTS; NITRIC-OXIDE; ODD NITROGEN; TRANSPORT; MESOSPHERE; DEPLETION; CYCLE-21 AB The very large solar proton events (SPEs) which occurred from October 19 to 27, 1989, caused substantial middle-atmospheric HOx and NOx constituent increases. Although no measurements of HOx increases were made during these SPEs, increases in NO were observed by rocket instruments which are in good agreement with calculated NO increases from our proton energy degradation code. Both the HOx and the NOx increases can cause ozone decreases; however, the HOx-induced ozone changes are relatively short-lived because HOx species have lifetimes of only hours in the middle atmosphere. Our two-dimensional model, when used to simulate effects of the longer-lived NOx, predicted lower-stratospheric polar ozone decreases of greater than 2% persisting for one and a half years past these SPEs. Previous three-dimensional model simulations of these SPEs (Jackman et al., 1993) indicated the importance of properly representing the polar vortices and warming events when accounting for the ozone decreases observed by the solar backscattered ultraviolet 2 instrument two months past these atmospheric perturbations. In an expansion of that study, we found that it was necessary to simulate the November 1, 1989, to April 2, 1990, time period and the November 1, 1986, to April 2, 1987, time period with our three-dimensional model in order to more directly compare to the stratospheric aerosol and gas experiment (SAGE) II observations of lower stratospheric NO2 and ozone changes between the end of March 1987 and 1990 at 70 degrees N. Both the NOx increases from the October 1989 SPEs and the larger downward transport in the 1989-1990 northern winter compared to the 1986-1987 northern winter contributed to the large enhancements in NO2 in the lower stratosphere observed in the SAGE II measurements at the end of March 1990, Our three-dimensional model simulations predict smaller ozone decreases than those observed by SAGE II in the lower stratosphere near the end of March 1990, indicating that other factors, such as heterogeneous chemistry, might also be influencing the constituents of this region. C1 APPL RES CORP, LANDOVER, MD 20785 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23665 USA. RP JACKMAN, CH (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RI Allen, Dale/F-7168-2010; Douglass, Anne/D-4655-2012; Jackman, Charles/D-4699-2012; McPeters, Richard/G-4955-2013; Rood, Richard/C-5611-2008 OI Allen, Dale/0000-0003-3305-9669; McPeters, Richard/0000-0002-8926-8462; Rood, Richard/0000-0002-2310-4262 NR 43 TC 58 Z9 58 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11641 EP 11660 DI 10.1029/95JD00369 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100047 ER PT J AU BACMEISTER, JT SCHOEBERL, MR SUMMERS, ME ROSENFIELD, JR ZHU, X AF BACMEISTER, JT SCHOEBERL, MR SUMMERS, ME ROSENFIELD, JR ZHU, X TI DESCENT OF LONG-LIVED TRACE GASES IN THE WINTER POLAR VORTEX SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC TRANSPORT; NUMERICAL ADVECTION; MIDDLE ATMOSPHERE; MODEL; CIRCULATION; OZONE; PARAMETERIZATION; DYNAMICS; RATES AB Recent observations of CH4 and HF from the UARS Halogen Limb Occultation Experiment (HALOE) suggest that vigorous descent occurs within the polar winter vortex with ''mesospheric'' values of CH4 evident down to 30 mbar. This study shows that a highly accurate two-dimensional model advection scheme coupled with a modern radiation scheme, parameterized planetary and gravity wave drag algorithms can produce tracer distributions consistent with HALOE observations. The modeled tracer distribution within the polar vortex is found to be principally dependent on the strength of dynamical drag in the middle atmosphere and the strength of the planetary wave forcing. However, the strong downward transport of tracers at the poles during winter can be disrupted in midwinter by planetary wave mixing. Thus the weaker planetary wave forcing in the southern hemisphere winter allows for a more coherent descent of long-lived tracers from the mesosphere than during the northern hemisphere winter. Multiple-year integrations of the model reveal a general circulation of the stratosphere which lofts tracers to mesospheric altitudes. Material removed from the mesosphere returns to the stratosphere principally within the polar regions. Upward vertical transport of material is found to be enhanced by horizontal planetary wave mixing. C1 UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. JOHNS HOPKINS UNIV, BALTIMORE, MD 21218 USA. RP BACMEISTER, JT (reprint author), USN, RES LAB, EO HULBURT CTR SPACE RES, CODE 7641, WASHINGTON, DC 20375 USA. RI Zhu, Xun/C-2097-2016 OI Zhu, Xun/0000-0001-7860-6430 NR 31 TC 43 Z9 43 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11669 EP 11684 DI 10.1029/94JD02958 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100049 ER PT J AU STEWART, RW AF STEWART, RW TI MULTIPLE STEADY-STATES IN ATMOSPHERIC CHEMISTRY - REPLY SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Note RP STEWART, RW (reprint author), NASA, GODDARD SPACE FLIGHT CTR, MAIL CODE 916, GREENBELT, MD 20771 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1995 VL 100 IS D6 BP 11703 EP 11703 DI 10.1029/95JD00847 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RF051 UT WOS:A1995RF05100053 ER PT J AU COHEN, EA HILLIG, KW PICKETT, HM AF COHEN, EA HILLIG, KW PICKETT, HM TI THE ROTATIONAL SPECTRA, HYPERFINE INTERACTIONS, AND O-17 MAGNETIC SHIELDINGS OF (OOO)-O-17-O-16-O-16, (OOO)-O-16-O-17-O-16, AND (OSO)-O-17-O-16 SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article ID MICROWAVE-SPECTRA; OZONE; SPECTROSCOPY; VIBRATION; MOLECULES; SHIFTS; STATES AB Measurement of the rotational spectra of (OOO)-O-17-O-16-O-16 and (OOO)-O-16-O-17-O-16 have been extended to allow the determination of a complete set of sextic centrifugal distortion constants for both molecules. A near degeneracy of the 3(12) and 4(04), levels of (OOO)-O-17-O-16-O-16 causes strong perturbations of the hyperfine patterns, gives rise to perturbation-allowed Delta J = 2. transitions, and provides an accurate determination of chi(ab). This has allowed the calculation of the angle between the principal axis of the quadrupole tenser and the O-O bond. The O-17 spin-rotation interactions of (OSO)-O-17-O-16 have been measured for comparison with the corresponding values in O-3, and improved values of the quadrupole coupling have been obtained. Paramagnetic shielding and chemical shifts for O-17 have been calculated from the spin-rotation constants for both compounds. C1 UNIV MICHIGAN, DEPT CHEM, ANN ARBOR, MI 48109 USA. RP COHEN, EA (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 34 TC 11 Z9 12 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 J9 J MOL STRUCT JI J. Mol. Struct. PD JUN 20 PY 1995 VL 352 BP 273 EP 282 DI 10.1016/0022-2860(95)08824-F PG 10 WC Chemistry, Physical SC Chemistry GA RD475 UT WOS:A1995RD47500029 ER PT J AU COHEN, EA OKUNISHI, M OH, JJ AF COHEN, EA OKUNISHI, M OH, JJ TI THE ISOTOPE EFFECT OF THE O-2 A(1)DELTA-G ROTATIONAL CONSTANT SO JOURNAL OF MOLECULAR STRUCTURE LA English DT Article ID SPECTRUM AB The pure rotational spectrum of a(1) Delta(g) oxygen in its first excited vibrational state as well as the ground vibrational state rotational spectra of (OO)-O-16-O-18 and O-18(2) in their a states have been observed. Precise parameters describing the spectra have been determined and an accurate value has been derived for the equilibrium interatomic distance in the Born-Oppenheimer limit. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. TOHOKU UNIV,SCI MEASUREMENTS RES INST,AOBA KU,SENDAI,MIYAGI 980,JAPAN. SOOKMYUNG WOMENS UNIV,SEOUL 140742,SOUTH KOREA. RP COHEN, EA (reprint author), INST MOLEC SCI,OKAZAKI,AICHI 444,JAPAN. NR 15 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-2860 J9 J MOL STRUCT JI J. Mol. Struct. PD JUN 20 PY 1995 VL 352 BP 283 EP 287 DI 10.1016/0022-2860(95)08825-G PG 5 WC Chemistry, Physical SC Chemistry GA RD475 UT WOS:A1995RD47500030 ER PT J AU LEE, TJ RACINE, SC RICE, JE RENDELL, AP AF LEE, TJ RACINE, SC RICE, JE RENDELL, AP TI ON THE ORBITAL CONTRIBUTION TO ANALYTICAL DERIVATIVES OF PERTURBATION-THEORY ENERGIES SO MOLECULAR PHYSICS LA English DT Article ID COUPLED-CLUSTER METHODS; TRIPLE EXCITATIONS; MANY-BODY; ANALYTICAL DIFFERENTIATION; GRADIENT EVALUATION; FORMULATION; SINGLE AB A new approach for determining the orbital contribution to analytical derivatives of perturbation theory energies is presented. The usefulness of the new approach is demonstrated by application to closed-shell second-order Moller-Plesset perturbation theory (MP2). This new method is related to that used previously (Lee, T. J., and Rendell, A. P., 1991, J. chem. Phys., 94, 6229) for analytical energy gradients of the closed-shell singles and doubles coupled-cluster method augmented with a perturbational estimate of the effects of connected triple excitations, CCSD(T), but it is more appealing in that potential singularities are rigorously eliminated. The computational savings for MP2 are modest (two n(5) steps, where n is the number of molecular orbitals), but the savings for fourth-order perturbation theory (MP4) or CCSD(T) energy gradients (two n(7) steps) are significant. Hence the new approach is less expensive than previous applications of analytical gradient theory to perturbation theory electron correlation energies, and it is numerically stable. C1 IBM CORP, ALMADEN RES CTR, DIV RES, SAN JOSE, CA 95120 USA. DRAL, DARESBURY LAB, WARRINGTON WA4 4AD, CHESHIRE, ENGLAND. RP LEE, TJ (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Rendell, Alistair/A-4883-2008; Rice, Julia/K-4928-2012; Lee, Timothy/K-2838-2012 OI Rendell, Alistair/0000-0002-9445-0146; Rice, Julia/0000-0001-5059-5127; NR 22 TC 12 Z9 12 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD JUN 20 PY 1995 VL 85 IS 3 BP 561 EP 571 DI 10.1080/00268979500101301 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RM016 UT WOS:A1995RM01600009 ER PT J AU KLEMPERER, W LUO, XC ROSNER, R SCHRAMM, DN AF KLEMPERER, W LUO, XC ROSNER, R SCHRAMM, DN TI ON THE POSSIBILITY OF COHERENTLY STIMULATED RECOMBINATION AND COSMOLOGICAL STRUCTURE GENERATION - RECOMBINATION INSTABILITY SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article AB Possible instabilities during cosmological recombination may produce an epoch of nonlinear density growth and fractal-like structural patterns out to the horizon scale at that epoch (approximate to 200 Mpc today). With this motivation, we examine the consequences of the change in effective radiative recombination reaction rate coefficients produced by intense stimulated emission. The proton-electron recombination is considered as a natural laser, leading to the Formation of spatially nonuniform distributions of neutral matter earlier than the recombination epoch. C1 UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP KLEMPERER, W (reprint author), HARVARD UNIV,DEPT CHEM PHYS,12 OXFORD ST,CAMBRIDGE,MA 02138, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU NATL ACAD SCIENCES 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 JUN 20 PY 1995 VL 92 IS 13 BP 6166 EP 6170 DI 10.1073/pnas.92.13.6166 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RF050 UT WOS:A1995RF05000084 PM 11607552 ER PT J AU SCHRAMM, DN ROSNER, R LUO, XC KLEMPERER, W AF SCHRAMM, DN ROSNER, R LUO, XC KLEMPERER, W TI ON THE POSSIBILITY OF COHERENTLY STIMULATED RECOMBINATION AND COSMOLOGICAL STRUCTURE GENERATION - COSMOLOGICAL CONSEQUENCES SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID UNIVERSE AB Given a specific physical mechanism for instabilities during cosmological recombination discussed in an earlier paper, we examine the nonlinear growth of density structures to form fractal-like structural patterns out to the horizon scale at that epoch (similar to 200 Mpc today), A model for such fractal patterns is presented. Such effects could explain observed large-scale structure patterns and the formation of objects at high z, while keeping microwave background anisotropies at the observed minimal levels. We also discuss possible microwave background implications of such a transition and note a potentially observable spectral signature at lambda similar to 0.18 mm as well as a weak line near the peak in the microwave background. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. HARVARD UNIV,DEPT PHYS CHEM,CAMBRIDGE,MA 02138. RP SCHRAMM, DN (reprint author), UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 19 TC 1 Z9 1 U1 1 U2 1 PU NATL ACAD SCIENCES 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 JUN 20 PY 1995 VL 92 IS 13 BP 6171 EP 6174 DI 10.1073/pnas.92.13.6171 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RF050 UT WOS:A1995RF05000085 PM 11607553 ER PT J AU ORIENT, OJ CHUTJIAN, A AF ORIENT, OJ CHUTJIAN, A TI DETECTION OF NEW DISSOCIATIVE ELECTRON-ATTACHMENT CHANNELS IN NO SO PHYSICAL REVIEW LETTERS LA English DT Article RP ORIENT, OJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 9 TC 15 Z9 15 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 JUN 19 PY 1995 VL 74 IS 25 BP 5017 EP 5019 DI 10.1103/PhysRevLett.74.5017 PG 3 WC Physics, Multidisciplinary SC Physics GA RD283 UT WOS:A1995RD28300013 ER PT J AU KULKARNI, M NOOR, AK AF KULKARNI, M NOOR, AK TI SENSITIVITY ANALYSIS FOR THE DYNAMIC-RESPONSE OF VISCOPLASTIC SHELLS OF REVOLUTION SO COMPUTERS & STRUCTURES LA English DT Article ID AXISYMMETRIC STRUCTURES AB A computational procedure is presented for evaluating the sensitivity coefficients of the dynamic axisymmetric response of viscoplastic shells of revolution. The analytical formulation is based on Reissner's large deformation shell theory with the effects of transverse shear deformation, rotatory inertia and moments turning around the normal to the middle surface included. The material model is chosen to be isothermal viscoplasticity, and an associated flow rule is used with a von Mises effective stress. A mixed formulation is used with the fundamental unknowns consisting of six stress resultants, three generalized displacements and three velocity components. Spatial discretization is performed using finite elements, with discontinuous stress resultants across element interfaces. The temporal integration is performed by using an explicit central difference scheme (leap-frog method) with an implicit constitutive update. The sensitivity coefficients are evaluated using a direct differentiation approach. Numerical results are presented for a spherical cap subjected to step loading, and a circular plate subjected to impulsive loading. The sensitivity coefficients are generated by evaluating the derivatives of the response quantities with respect to the thickness, mass density, Young's modulus, and two of the material parameters characterizing the viscoplastic response. Time histories of the response and sensitivity coefficients are presented, along with spatial distributions of these quantities at selected times. RP KULKARNI, M (reprint author), UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681, USA. NR 16 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD JUN 17 PY 1995 VL 55 IS 6 BP 955 EP 969 DI 10.1016/0045-7949(94)00520-D PG 15 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA QX817 UT WOS:A1995QX81700002 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI A STUDY OF THE X-(2)SIGMA(+) AND A-(2)PI STATES OF MGAR+ AND MGKR+ SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTODISSOCIATION SPECTROSCOPY; BASIS-SETS; ATOMS; IONS; MG+-H2O; MG+-CO2; 1ST-ROW; NE; AR AB The ground (2) Sigma(+) and lowest excited (II)-I-2 states of MgAr+ and MgKr+ are studied using the singles and doubles configuration-interaction (SDCI) approach, in conjunction with large basis sets. The effect of Mg core correlation and core polarization are accounted for using the core-polarization potential (CPP) approach. Franck-Condon factors, oscillator strengths, radiative lifetimes, dissociation energies, bond lengths, and excitation energies are reported. The computed results are in good agreement with the available experimental data. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 24 TC 34 Z9 34 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 16 PY 1995 VL 239 IS 4-6 BP 241 EP 245 DI 10.1016/0009-2614(95)00449-E PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RE253 UT WOS:A1995RE25300007 ER PT J AU BAUSCHLICHER, CW PARTRIDGE, H AF BAUSCHLICHER, CW PARTRIDGE, H TI THE C-H DISSOCIATION-ENERGY OF C2H6 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID COUPLED-CLUSTER THEORY; GAUSSIAN-BASIS SETS; ELECTRON CORRELATION; PERTURBATION-THEORY; MOLLER-PLESSET; HEAT; THERMOCHEMISTRY; KINETICS; HYDROGEN; SPIN AB The C-H bond energy in C2H6 is computed to be 99.76+/-0.45 kcal/mol, which is in excellent agreement with the most recent experimental values. The calculation of the C-H bond energy by direct dissociation and by an isodesmic reaction is discussed. RP BAUSCHLICHER, CW (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 34 TC 11 Z9 12 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 16 PY 1995 VL 239 IS 4-6 BP 246 EP 251 DI 10.1016/0009-2614(95)00456-E PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RE253 UT WOS:A1995RE25300008 ER PT J AU BAUSCHLICHER, CW AF BAUSCHLICHER, CW TI THE BOND-DISSOCIATION ENERGIES OF 1-BUTENE SO CHEMICAL PHYSICS LETTERS LA English DT Article ID COUPLED-CLUSTER THEORY; PHOTOELECTRON-SPECTROSCOPY; ELECTRON CORRELATION; PERTURBATION-THEORY; MOLLER-PLESSET; BASIS-SETS; THERMOCHEMISTRY; ACETYLENE; RADICALS; KINETICS AB The bond dissociation energies of 1-butene (CH2=CHCH2CH3) and several calibration systems are computed using the G2(MP2) approach. The agreement between the calibration systems and experiment is very good. The computed values for l-butene are compared with those for the calibration systems and the agreement between the computed results for l-butene and the 'rule of thumb' values from the smaller systems is remarkably good. RP BAUSCHLICHER, CW (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 26 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 16 PY 1995 VL 239 IS 4-6 BP 252 EP 257 DI 10.1016/0009-2614(95)00450-I PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RE253 UT WOS:A1995RE25300009 ER PT J AU WAITE, JH GLADSTONE, GR FRANKE, K LEWIS, WS FABIAN, AC BRANDT, WN NA, C HABERL, F CLARKE, JT HURLEY, KC SOMMER, M BOLTON, S AF WAITE, JH GLADSTONE, GR FRANKE, K LEWIS, WS FABIAN, AC BRANDT, WN NA, C HABERL, F CLARKE, JT HURLEY, KC SOMMER, M BOLTON, S TI ROSAT OBSERVATIONS OF X-RAY EMISSIONS FROM JUPITER DURING THE IMPACT OF COMET SHOEMAKER-LEVY-9 SO SCIENCE LA English DT Article ID MAGNETOSPHERE AB Rontgensatellit (ROSAT) observations made shortly before and during the collision of comet Shoemaker-Levy 9 with Jupiter show enhanced x-ray emissions from the planet's northern high latitudes. These emissions, which occur at System III longitudes where intensity enhancements have previously been observed in Jupiter's ultraviolet aurora, appear to be associated with the comet fragment impacts in Jupiter's southern hemisphere and may represent brightenings of the jovian x-ray aurora caused either by the fragment impacts themselves or by the passage of the fragments and associated dust clouds through Jupiter's inner magnetosphere, C1 UNIV CAMBRIDGE,INST ASTRON,CAMBRIDGE CB3 0HA,ENGLAND. MAX PLANCK INST EXTRATERR PHYS,D-85740 GARCHING,GERMANY. UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP WAITE, JH (reprint author), SW RES INST,DEPT SPACE SCI,POB 28510,SAN ANTONIO,TX 77228, USA. RI Clarke, John/C-8644-2013; Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 20 TC 19 Z9 19 U1 1 U2 3 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 16 PY 1995 VL 268 IS 5217 BP 1598 EP 1601 DI 10.1126/science.268.5217.1598 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RD459 UT WOS:A1995RD45900031 PM 17754612 ER PT J AU SU, Y DIBBLE, TS FRANCISCO, JS LI, Z AF SU, Y DIBBLE, TS FRANCISCO, JS LI, Z TI DISSOCIATION OF ACETYL BROMIDE - AN EXPERIMENTAL AND THEORETICAL-STUDY SO CHEMICAL PHYSICS LA English DT Article ID BASIS-SETS AB We examine the ground state dissociation pathways of acetyl bromide, CH3C(O)Br, using infrared multiphoton dissociation and ab initio molecular orbital theory. Experiments reveal stable products C2H6, CH3Br, and CO which are consistent with the C-Br bond fission pathway. However, production of C2H4 is consistent with ketene (CH2CO) formation, which has been a suggested intermediate in the dissociation of CH3C(O)Br. Calculations indicate that the activation energy for the molecular dissociation of CH3C(O)Br into ketene and HBr exceeds the C-Br bond energy of 64 kcal mol(-1) by about 30 kcal mol(-1), implying that ketene may be formed by secondary chemistry rather than by molecular dissociation of acetyl bromide. C1 WAYNE STATE UNIV,DEPT CHEM,DETROIT,MI 48202. CALTECH,JET PROP LAB,PASADENA,CA 91109. RI Dibble, Theodore/D-1341-2012; OI Dibble, Theodore/0000-0002-0023-8233 NR 14 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD JUN 15 PY 1995 VL 196 IS 1-2 BP 59 EP 67 DI 10.1016/0301-0104(95)00100-3 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RE469 UT WOS:A1995RE46900005 ER PT J AU BURTON, WS NOOR, AK AF BURTON, WS NOOR, AK TI ASSESSMENT OF COMPUTATIONAL MODELS FOR SANDWICH PANELS AND SHELLS SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID HYGROTHERMAL LOADS; LAMINATE FACINGS; BEAMS; COMPOSITE; PLATES AB A study is made of the effects of variation in the material and geometric parameters of curved sandwich panels on the accuracy of the static response predicted by nine different modeling approaches based on two-dimensional shell theories. The standard of comparison is taken to be the exact three-dimensional thermoelasticity solutions, and the quantities compared include gross response characteristics (e.g. strain energy components, average through-the-thickness displacements and rotations); detailed, through-the-thickness distributions of displacements and stresses; and sensitivity coefficients of the response quantities (derivatives of response quantities with respect to material and geometric parameters of the sandwich structure). Extensive numerical studies are conducted to assess the accuracy of both the global and detailed response characteristics and their sensitivity coefficients obtained by nine two-dimensional modeling approaches. For accurate determination of detailed through-the-thickness distributions such as transverse stresses, either high-order discrete three-layer models or predictor-corrector approaches are required. The potential of predictor-corrector approaches for predicting the thermomechanical response of sandwich panels and shells with complicated geometry is also discussed. C1 UNIV VIRGINIA,NASA,LANGLEY RES CTR,CTR COMPUTAT STRUCT TECHNOL,HAMPTON,VA 23681. NR 29 TC 52 Z9 52 U1 1 U2 20 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. Methods Appl. Mech. Eng. PD JUN 15 PY 1995 VL 124 IS 1-2 BP 125 EP 151 DI 10.1016/0045-7825(94)00750-H PG 27 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA RK747 UT WOS:A1995RK74700008 ER PT J AU HABBAL, SR ESSER, R GUHATHAKURTA, M FISHER, RR AF HABBAL, SR ESSER, R GUHATHAKURTA, M FISHER, RR TI FLOW PROPERTIES OF THE SOLAR-WIND DERIVED FROM A 2-FLUID MODEL WITH CONSTRAINTS FROM WHITE-LIGHT AND IN-SITU INTERPLANETARY OBSERVATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL HOLE; DYNAMICS AB We derive the flow properties of the solar wind in coronal holes using a two-fluid model constrained by density profiles inferred from simultaneous space-based SPARTAN 201-01 and ground-based Mauna Loa White Light coronagraph observations, and by in situ interplanetary measurements. Also used as a guide is the hydrostatic temperature profile derived from the density gradient. Density profiles are inferred between 1.16 and 5.5 R(s), for two different density structures observed along the line of sight in a polar coronal hole. The model computations that fit remarkably well the empirical constraints yield a supersonic flow at 2.3 R(s) for the less dense ambient coronal hole, and at 3.4 R(s) for the denser structures. The novel result that emerges from these fits is a proton temperature twice as large as the electron temperature in the inner corona, reaching a peak of 2 x 10(6) K at 2 R(s). C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD USA. RP HARVARD SMITHSONIAN CTR ASTROPHYS, 60 GARDEN ST, MS-15, CAMBRIDGE, MA 02138 USA. NR 14 TC 108 Z9 108 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1465 EP 1468 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800001 ER PT J AU CREWELL, S FABIAN, R KUNZI, K NETT, H WEHR, T READ, W WATERS, J AF CREWELL, S FABIAN, R KUNZI, K NETT, H WEHR, T READ, W WATERS, J TI COMPARISON OF CLO MEASUREMENTS BY AIRBORNE AND SPACEBORNE MICROWAVE RADIOMETERS IN THE ARCTIC WINTER STRATOSPHERE 1993 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE AB In February 1993 measurements of chlorine monoxide ClO, one of the key substances in catalytic ozone destruction, were performed over Scandinavia by two microwave receivers, the Submillimeter Atmospheric Sounder (SUMAS) on board the German research aircraft FALCON and the Microwave Limb Sounder (MLS) on board the Upper Atmospheric Research Satellite (UARS). High ClO concentrations (>1 ppb) inside the polar vortex at approximately 20 km altitude were detected by both experiments. A comparison shows good agreement of both sensors in the location of enhanced ClO. C1 UNIV BREMEN,INST ENVIRONM PHYS,W-2800 BREMEN,GERMANY. JET PROP LAB,PASADENA,CA. RI Crewell, Susanne/O-1640-2013 OI Crewell, Susanne/0000-0003-1251-5805 NR 11 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1489 EP 1492 DI 10.1029/95GL01390 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800007 ER PT J AU ZHANG, RY LEU, MT KEYSER, LF AF ZHANG, RY LEU, MT KEYSER, LF TI HYDROLYSIS OF N2O5O AND CLONO2 ON THE H2SO4/HNO3/H2O TERNARY SOLUTIONS UNDER STRATOSPHERIC CONDITIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SULFATE AEROSOLS AB The reaction probabilities of N2O5 and ClONO2 with H2O on liquid sulfuric acid surfaces have been reexamined to determine the effect of HNO3 on these two hydrolysis rates, using a fast flow reactor coupled to a chemical ionization mass spectrometer. The measurements were carried out by maintaining constant H2O and HNO3 partial pressures and by varying temperatures between 227 and 195 K in order to mimic compositions representative of stratospheric aerosols. For experiments excluding HNO3, the reaction probability of N2O5 hydrolysis was found to be near 0.1, independent of temperature and H2SO4 content. This is in agreement with results previously measured under similar conditions. In the presence of gaseous HNO3 at stratospheric concentrations, the reaction probability was observed to decrease from about 0.09 at 218 K to about 0.02-0.03 at 195 K for P-H2O = 3.8x10(-4)-1.0x10(-3) Torr, showing that incorporation of HNO3 into liquid sulfuric acid greatly retarded the N2O5 hydrolysis. The ClONO2 reaction with H2O on liquid sulfuric acid, on the other hand, did not appear to be affected by the presence of HNO3. RP ZHANG, RY (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Zhang, Renyi/A-2942-2011 NR 22 TC 57 Z9 57 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1493 EP 1496 DI 10.1029/95GL01177 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800008 ER PT J AU CARLSON, RW WEISSMAN, PR SEGURA, M HUI, J SMYTHE, WD JOHNSON, TV BAINES, KH DROSSART, P ENCRENAZ, T LEADER, FE AF CARLSON, RW WEISSMAN, PR SEGURA, M HUI, J SMYTHE, WD JOHNSON, TV BAINES, KH DROSSART, P ENCRENAZ, T LEADER, FE TI GALILEO INFRARED OBSERVATIONS OF THE SHOEMAKER-LEVY-9 G-IMPACT FIREBALL - A PRELIMINARY-REPORT SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID JUPITER AB The Galileo spacecraft was fortuitously situated for a direct view of the impacts of the fragments of comet Shoemaker-Levy 9 in Jupiter's atmosphere. The Galileo Near Infrared Mapping Spectrometer (NIMS) instrument observed several of the impact events in several discrete bands and with a temporal resolution of roughly five seconds. Data have been received for the G impact showing two phases of strong infrared emission. The first phase is approximately one minute in duration and corresponds to the initial fireball and early plume development. This is followed six minutes later by the onset of heating by plume ejecta falling back on the upper atmosphere. This report provides a preliminary description of the fireball phase. The first detection of the G fireball occurred at 07:33:37 UT on July 18, 1994, approximately five seconds after the initial signal recorded by the Galileo Photopolarimeter-Radiometer (PPR) instrument. The preceding NIMS measurement, occurring approximately one second before the initial PPR signal, showed no evidence of fireball emission. The detected duration of the fireball at 4.38 mu m was 70 seconds. Spectra in the first half of this period show blackbody-like emission, with absorption features from overlying methane and molecular hydrogen. The strengths of these features place the fireball in the upper troposphere and lower stratosphere, above the ammonia cloud layer. The emitting surface rises and accelerates, achieving a velocity of 2 - 3 km/sec after 25 seconds, in qualitative agreement with that expected for an explosion in an inhomogeneous atmosphere. The Galileo spacecraft, en route to Jupiter, was in a position to obtain a direct view of the impacts of Comet Shoemaker-Levy 9 fragments on the nightside of Jupiter, providing an opportunity to investigate the early temporal evolution of the impact events. It was predicted that the comet fragments would produce high temperature bolides as they entered the atmosphere and then explode, producing hot fireballs which would rise, expand, and cool (Sekanina, 1993; Zahnle and Mac Low, 1994; Chevalier and Sarazin, 1994; Ahrens et al., 1994; Boslough et al., 1994). Much of the predicted radiation occurs in the infrared region, and time-resolved infrared spectral observations, obtained over a broad wavelength range, are ideal for studying these phenomena. C1 OBSERV PARIS,DESPA,F-92150 MEUDON,FRANCE. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. RP CARLSON, RW (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 31 Z9 31 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1557 EP 1560 DI 10.1029/95GL01189 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800025 ER PT J AU CHAPMAN, CR MERLINE, WJ KLAASEN, K JOHNSON, TV HEFFERNAN, C BELTON, MJS INGERSOLL, AP AF CHAPMAN, CR MERLINE, WJ KLAASEN, K JOHNSON, TV HEFFERNAN, C BELTON, MJS INGERSOLL, AP TI PRELIMINARY-RESULTS OF GALILEO DIRECT IMAGING OF S-L-9 IMPACTS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Direct Galileo imaging data were obtained of the Jupiter impact sites for Comet Shoemaker-Levy 9 fragments K, N, and W during their early, high-energy phases. Initial similar to 5s-long flashes for all 3 impacts result from radiant bolides; analogous, abrupt onsets of luminosity observed by the Galileo photopolarimeter for other impacts must also be the bolide phase. The 3 bolides were dim at 0.56 or 0.89 mu m (few percent of total Jupiter) and had similar amplitudes, despite huge late-stage differences observed from Earth. Subsequent, continuous luminosity lasting similar to 40s for K and similar to 10s for N is optical radiation as the initial bolide train erupts into a ''fireball''. The K light curve may show (a) two impacts 10s apart or (b) delayed evolution of the fireball. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NATL OPT ASTRON OBSERV,TUCSON,AZ 85726. CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP CHAPMAN, CR (reprint author), PLANETARY SCI INST,620 N 6TH AVE,TUCSON,AZ 85705, USA. NR 10 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1561 EP 1564 DI 10.1029/95GL01030 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800026 ER PT J AU HORD, CW PRYOR, WR STEWART, AIF SIMMONS, KE GEBBEN, JJ BARTH, CA MCCLINTOCK, WE ESPOSITO, LW TOBISKA, WK WEST, RA EDBERG, SJ AJELLO, JM NAVIAUX, KL AF HORD, CW PRYOR, WR STEWART, AIF SIMMONS, KE GEBBEN, JJ BARTH, CA MCCLINTOCK, WE ESPOSITO, LW TOBISKA, WK WEST, RA EDBERG, SJ AJELLO, JM NAVIAUX, KL TI DIRECT OBSERVATIONS OF THE COMET SHOEMAKER-LEVY-9 FRAGMENT-G IMPACT BY GALILEO UVS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ULTRAVIOLET AB The Galileo Ultraviolet Spectrometer (UVS) team has detected the Shoemaker-Levy 9 fragment G impact on Jupiter in data recently played back from the spacecraft tape recorder. A 20% brightening of the disc-integrated signal of Jupiter was detected at 292 nm during a swath across Jupiter that lasted 1.6 sec and was centered at 1994-July 18 (day 199)/07:33:31 UT (all times in this paper are corrected to be the time of the event as seen from Earth). The emission brightness, when combined with simultaneous Photopolarimeter Radiometer (PPR) measurements at 945 nm, is consistent with thermal radiation at a temperature of 7800 (+500, -600) K emitted over an area of 40 (+60, -25) km(2). No excess signal was seen during swaths 5 1/3 sec before and after the detection swath. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP HORD, CW (reprint author), UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,CAMPUS BOX 392,BOULDER,CO 80303, USA. NR 10 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1565 EP 1568 DI 10.1029/95GL01414 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800027 ER PT J AU FRIEDSON, AJ HOFFMANN, WF GOGUEN, JD DEUTSCH, LK ORTON, GS HORA, JL DAYAL, A SPITALE, JN WELLS, WK FAZIO, GG AF FRIEDSON, AJ HOFFMANN, WF GOGUEN, JD DEUTSCH, LK ORTON, GS HORA, JL DAYAL, A SPITALE, JN WELLS, WK FAZIO, GG TI THERMAL INFRARED LIGHTCURVES OF THE IMPACT OF COMET SHOEMAKER-LEVY-9 FRAGMENT-R SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB The impact of fragment R was observed at thermal infrared wavelengths of 7.85, 10.3 and 12.2 mu m from the NASA/Infrared Telescope Facility on July 21 UT, using the MIRAC2 mid-infrared array camera. Thermal emission at the three wavelengths was sampled sequentially using a 1.8% circular variable filter, with an average time interval of 17 seconds between observations at different wavelengths. Continuous imaging of Jupiter in this mode began at 5:08 UT and extended to 5:55 UT. We present calibrated lightcurves for the three wavelengths. Clear evidence for enhanced emission from the impact region first appears at 5:41 UT, with the peak in emission at all three wavelengths occurring similar to 3.5 minutes later. The information content of the data is presented in terms of plots of the product of emissivity times angular size versus source temperature for each wavelength. Assuming that the peak in the lightcurves is due to rotation of the hot impact site into view from Earth, we estimate a diameter of similar to 1900 km for the source emitting area at 5:44:30 UT and estimate a lower limit on the source temperature at this time of similar to 1350 K. This lower limit drops to 800 K if the diameter of the emitting region was actually a factor of two larger. C1 UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ. UNIV MASSACHUSETTS,FCAD,AMHERST,MA. UNIV HAWAII,INST ASTRON,HONOLULU,HI. CALTECH,PASADENA,CA. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ. SMITHSONIAN ASTROPHYS OBSERV,BOSTON,MA. RP FRIEDSON, AJ (reprint author), CALTECH,JET PROP LAB,MS 169-237,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 6 TC 8 Z9 8 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1569 EP 1572 DI 10.1029/95GL00359 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800028 ER PT J AU MARTEN, A GAUTIER, D GRIFFIN, MJ MATTHEWS, HE NAYLOR, DA DAVIS, GR OWEN, T ORTON, G BOCKELEEMORVAN, D COLOM, P CROVISIER, J LELLOUCH, E DEPATER, I ATREYA, S STOBEL, D HAN, B SANDERS, DB AF MARTEN, A GAUTIER, D GRIFFIN, MJ MATTHEWS, HE NAYLOR, DA DAVIS, GR OWEN, T ORTON, G BOCKELEEMORVAN, D COLOM, P CROVISIER, J LELLOUCH, E DEPATER, I ATREYA, S STOBEL, D HAN, B SANDERS, DB TI THE COLLISION OF COMET SHOEMAKER-LEVY-9 WITH JUPITER - DETECTION AND EVOLUTION OF HCN IN THE STRATOSPHERE OF THE PLANET SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB We report submillimeter heterodyne observations of Jupiter taken with the JCMT during and after the infall of Comet Shoemaker-Levy 9 into the planet. We detected the J=4-3 and J=3-2 rotational transitions of HCN in emission at many of the impact sites. Measurements suggest for fragment G a mixing ratio of similar to 5x10(-8) above the 0.5-mbar pressure level and a total HCN mass of 6 x 10(11)g. Subsequent observations, made in September and November 1994, reveal that HCN is still present but that the lines now appear in absorption. This results from a cooling of the stratospheric thermal profile between July and September. Chemical implications of the observed persistence of HCN in the Jovian stratosphere for over 6 months are discussed. C1 UNIV LONDON QUEEN MARY & WESTFIELD COLL,LONDON E1 4NS,ENGLAND. JOINT ASTRON CTR,HILO,HI 96720. UNIV LETHBRIDGE,LETHBRIDGE,AB T1K 3M4,CANADA. UNIV SASKATCHEWAN,SASKATOON,SK,CANADA. UNIV HAWAII,INST ASTRON,HONOLULU,HI 96822. CALTECH,JET PROP LAB,PASADENA,CA. UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV MICHIGAN,ANN ARBOR,MI 48109. JOHNS HOPKINS UNIV,BALTIMORE,MD 21205. RP MARTEN, A (reprint author), OBSERV PARIS,F-92195 MEUDON,FRANCE. NR 13 TC 20 Z9 20 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1589 EP 1592 DI 10.1029/95GL00949 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800033 ER PT J AU ZAHNLE, K MACLOW, MM LODDERS, K FEGLEY, B AF ZAHNLE, K MACLOW, MM LODDERS, K FEGLEY, B TI SULFUR CHEMISTRY IN THE WAKE OF COMET SHOEMAKER-LEVY-9 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB A curious and unexpected result of the impact of P/Shoemaker Levy 9 with Jupiter was the production of enormous amounts of molecular sulfur (S-2). Here we show that S-2 is the natural product of disequilibrium chemistry at low pressures in shocked jovian air, its formation a byproduct of hydrogen recombination. The species observed by the HST - S-2, CS2, and H2S - imply that the G fragment penetrated the NH4 SH cloud but did not reach the water table. A typical impact within or below the NH4SH clouds produces about 0.03-0.1 impactor masses of S-2. Because comets are relatively hydrogen-poor, SO2, not S-2, is the major product of shocking a water-rich comet, while S-2, CS2, and OCS are major products of a dessicated comet. In all cases we find that as the gas cools St converts to the stable low temperature allotrope S-8, although other chemical fates not modeled here might intervene first. C1 UNIV CHICAGO,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. WASHINGTON UNIV,DEPT EARTH & PLANETARY SCI,ST LOUIS,MO 63130. RP ZAHNLE, K (reprint author), NASA,AMES RES CTR,MS 245-3,MOFFETT FIELD,CA 94035, USA. OI Mac Low, Mordecai-Mark/0000-0003-0064-4060 NR 13 TC 37 Z9 37 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1593 EP 1596 DI 10.1029/95GL01190 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800034 ER PT J AU MOSES, JI ALLEN, M GLADSTONE, GR AF MOSES, JI ALLEN, M GLADSTONE, GR TI POST-SL9 SULFUR PHOTOCHEMISTRY ON JUPITER SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB We have modeled the photochemical evolution of the sulfur-containing species that were observed in Jupiter's stratosphere after the SL9 impacts. We find that most of the sulfur is converted to S-8 in the first few days. Other important sulfur reservoirs are CS, whose abundance increases markedly with time, and possibly H2CS, HNCS, and NS, whose abundances depend on kinetic reaction rates that are unknown at the present. We discuss the temporal variation of the major sulfur compounds, make abundance and compositional predictions useful for comparisons with observations, and discuss the possible condensation of sulfur-containing species. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. SW RES INST,SAN ANTONIO,TX 78284. RP MOSES, JI (reprint author), LUNAR & PLANETARY INST,3600 BAY AREA BLVD,HOUSTON,TX 77058, USA. RI Moses, Julianne/I-2151-2013 OI Moses, Julianne/0000-0002-8837-0035 NR 13 TC 30 Z9 30 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1597 EP 1600 DI 10.1029/95GL01200 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800035 ER PT J AU NICHOLSON, PD GIERASCH, PJ HAYWARD, TL MCGHEE, CA MOERSCH, JE SQUYRES, SW VANCLEVE, J MATTHEWS, K NEUGEBAUER, G SHUPE, D WEINBERGER, A MILES, JW CONRATH, BJ AF NICHOLSON, PD GIERASCH, PJ HAYWARD, TL MCGHEE, CA MOERSCH, JE SQUYRES, SW VANCLEVE, J MATTHEWS, K NEUGEBAUER, G SHUPE, D WEINBERGER, A MILES, JW CONRATH, BJ TI PALOMAR OBSERVATIONS OF THE R-IMPACT OF COMET SHOEMAKER-LEVY-9 .1. LIGHT CURVES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB We present near-infrared observations from Palomar observatory of the impact of fragment R of comet Shoemaker-Levy 9 with Jupiter on 21 July 1994. Two instruments were used to image the event at 3.2 and 4.5 microns simultaneously. The lightcurves from these image sequences both show two faint precursor flashes, a bright main peak, and several oscillations over the following hour. We identify the precursor flashes with the entry of the bolide into Jupiter's upper atmosphere, and with the post-impact ejecta plume rising above the planet's limb. The main peak is due to the re-entry of the collapsing plume into Jupiter's atmosphere and the resultant shock heating. C1 CALTECH,PALOMAR OBSERV,DOWNS LAB 320 47,PASADENA,CA 91125. SMITHSONIAN INST,NATL AIR & SPACE MUSEUM,WASHINGTON,DC 20560. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP NICHOLSON, PD (reprint author), CORNELL UNIV,CTR RADIOPHYS & SPACE RES,SPACE SCI BLDG,ITHACA,NY 14853, USA. RI Moersch, Jeffrey/F-7189-2010; OI Weinberger, Alycia/0000-0001-6654-7859 NR 9 TC 20 Z9 20 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1613 EP 1616 DI 10.1029/95GL01179 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800039 ER PT J AU NICHOLSON, PD GIERASCH, PJ HAYWARD, TL MCGHEE, CA MOERSCH, JE SQUYERS, SW VANCLEVE, J MATTHEWS, K NEUGEBAUER, G SHUPE, D WEINBERGER, A MILES, JW CONRATH, BJ AF NICHOLSON, PD GIERASCH, PJ HAYWARD, TL MCGHEE, CA MOERSCH, JE SQUYERS, SW VANCLEVE, J MATTHEWS, K NEUGEBAUER, G SHUPE, D WEINBERGER, A MILES, JW CONRATH, BJ TI PALOMAR OBSERVATIONS OF THE R IMPACT OF COMET SHOEMAKER-LEVY-9 .2. SPECTRA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERSTELLAR AB We present mid-infrared spectroscopic observations from Palomar observatory of the impact of fragment R of comet P/Shoemaker-Levy 9 with Jupiter on 21 July 1994. Low-resolution 8-13 mum spectra taken near the peak of the lightcurve show a broad emission feature that resembles the silicate feature commonly seen in comets and the interstellar medium. We use this feature to estimate the dust content of the impact plume. The overall infrared spectral energy distribution at the time of peak brightness is consistent with emission from an optically-thin layer of small particles at approximate to 600 K. Integrating over the spectrum and the lightcurve, we obtain a total radiated energy from the R impact of greater than or equal to 2x10(25) ergs and a plume mass of greater than or equal to 3x10(13) g. C1 CALTECH,PALOMAR OBSERV,DOWNS LAB 320-47,PASADENA,CA 91125. SMITHSONIAN INST,NATL AIR & SPACE MUSEUM,WASHINGTON,DC 20560. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP NICHOLSON, PD (reprint author), CORNELL UNIV,CTR RADIOPHYS & SPACE RES,SPACE SCI BLDG,ITHACA,NY 14853, USA. RI Moersch, Jeffrey/F-7189-2010; OI Weinberger, Alycia/0000-0001-6654-7859 NR 9 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 JUN 15 PY 1995 VL 22 IS 12 BP 1617 EP 1620 DI 10.1029/95GL01067 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800040 ER PT J AU MILLER, S ACHILLEOS, N DINELLI, BM LAM, HA TENNYSON, J JAGOD, MF GEBALLE, TR TRAFTON, LM JOSEPH, RD BALLESTER, GE BAINES, K BROOKE, TY ORTON, G AF MILLER, S ACHILLEOS, N DINELLI, BM LAM, HA TENNYSON, J JAGOD, MF GEBALLE, TR TRAFTON, LM JOSEPH, RD BALLESTER, GE BAINES, K BROOKE, TY ORTON, G TI THE EFFECT OF THE IMPACT OF COMET SHOEMAKER-LEVY-9 ON JUPITER AURORAE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB We present infrared spectra and images of the jovian aurorae taken at wavelengths sensitive to the H-3(+) molecular ion during the period around the impact of Comet Shoemaker Levy-9. The spectra were obtained using CGS4 on the United Kingdom Infrared Telescope and the images using NSF cam on NASA's Infrared Telescope Facility. Comparison with spectra obtained in May, 1993, shows that while the relative intensities of the northern and southern auroral zones prior to and during impact week (July 16 - 22, 1994) were broadly comparable with those of 1993, a few days after the last collision the northern aurora was considerably enhanced and its southern counterpart somewhat depressed. The north/south auroral ratio was returning to more normal values a week later. The effect of material drifting from the impact sites to the southern auroral zone is discussed in relation to these results. C1 UNIV CHICAGO, DEPT CHEM, CHICAGO, IL 60637 USA. UKIRT, JOINT ASTRON CTR, HILO, HI 96720 USA. UNIV TEXAS, MCDONALD OBSERV, AUSTIN, TX 78712 USA. UNIV HAWAII, INST ASTRON, HONOLULU, HI 96822 USA. UNIV MICHIGAN, DEPT ATMOSPHER OCEAN & SPACE SCI, ANN ARBOR, MI 48109 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP MILLER, S (reprint author), UNIV LONDON UNIV COLL, DEPT PHYS & ASTRON, GOWER ST, LONDON WC1E 6BT, ENGLAND. RI Achilleos, Nicholas/C-1647-2008; Tennyson, Jonathan/I-2222-2012; Dinelli, Bianca Maria/C-1212-2015 OI Tennyson, Jonathan/0000-0002-4994-5238; NR 13 TC 16 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1995 VL 22 IS 12 BP 1629 EP 1632 DI 10.1029/95GL00700 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RE528 UT WOS:A1995RE52800043 ER PT J AU DEMEIO, L GREEN, S MONCHICK, L AF DEMEIO, L GREEN, S MONCHICK, L TI EFFECTS OF VELOCITY CHANGING COLLISIONS ON LINE-SHAPES OF HF IN AR SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RAMAN-Q-BRANCH; TRANSITION; GAS; HE C1 NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP DEMEIO, L (reprint author), JOHNS HOPKINS UNIV, APPL PHYS LAB, MSE RES CTR, JOHNS HOPKINS RD, LAUREL, MD 20723 USA. NR 28 TC 30 Z9 30 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 1995 VL 102 IS 23 BP 9160 EP 9166 DI 10.1063/1.468864 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RD124 UT WOS:A1995RD12400002 ER PT J AU TENORE, KR ALONSONOVAL, M ALVAREZOSSORIO, M ATKINSON, LP CABANAS, JM CAL, RM CAMPOS, HJ CASTILLEJO, F CHESNEY, EJ GONZALEZ, N HANSON, RB MCCLAIN, CR MIRANDA, A ROMAN, MR SANCHEZ, J SANTIAGO, G VALDES, L VARELA, M YODER, J AF TENORE, KR ALONSONOVAL, M ALVAREZOSSORIO, M ATKINSON, LP CABANAS, JM CAL, RM CAMPOS, HJ CASTILLEJO, F CHESNEY, EJ GONZALEZ, N HANSON, RB MCCLAIN, CR MIRANDA, A ROMAN, MR SANCHEZ, J SANTIAGO, G VALDES, L VARELA, M YODER, J TI FISHERIES AND OCEANOGRAPHY OFF GALICIA, NW SPAIN - MESOSCALE SPATIAL AND TEMPORAL CHANGES IN PHYSICAL PROCESSES AND RESULTANT PATTERNS OF BIOLOGICAL PRODUCTIVITY SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WIND; COAST; RIAS; NORTHWEST; BIOMASS; AFRICA; AROSA; RATES; FISH AB The Galician shelf off NW Spain (43N degrees 9W degrees) exhibits mesoscale spatial and temporal changes in biological productivity associated with upwelling. Spatial heterogeneity results from local geomorphic and land-sea interactions superimposed on the large scale atmospheric processes that produce upwelling. Wind-induced upwelling events, commonly of short (i.e., week) duration, are more common in the summer than in the winter. A Series of cruises, including some time series sampling, and satellite imagery analysis showed that surface upwelling was more common and persistent on the northern coast compared with the western coast off the coastal embayments, the Rias Bajas. Nearshore off the rias, coastal runoff, which is greater in the rainy winter/spring versus the dry summer, affected upwelling. In early summer, upwelling less often reaches the surface because of increased water column stratification associated with lower surface salinities and thus upwelling is not detected by satellite imagery. Conversely, in late summer, upwelling more often reaches the surface because coastal runoff is reduced during the dry summer months and the water column tends to be less stratified. Plankton biomass and rate processes along the Galician shelf reflected both ambient hydrographic conditions as well as prior history of upwelling or downwelling. Phytoplankton and bacterioplankton were in greatest abundance during upwelling conditions (June through August); in contrast, both zooplankton and fish larvae exhibited highest abundances in March, when there were upwelling conditions prior to our cruise. Spatial differences in the duration and frequency of upwelling events, in combination with advection of water masses, are critical to the patterns of water column productivity and sardine fisheries production off the Galician coast. More persistent upwelling at this NW corner of the Iberian peninsula Supports large sardine fisheries because zooplankton and larval fish populations have time to respond to the higher primary production. Farther down the western Galician coast, the episodic upwelling and resultant intermittent primary production does not support a stable food supply needed to support fisheries. Times series sampling revealed mean response times of bacteria, phytoplankton, and zooplankton to be on the order of a day, days, and weeks, respectively. Sardines showed no spawning response in the relatively short time series sampling. The observed distributional patterns of fish eggs and larvae showed some offshore transport of fish larvae that were spawned inshore during upwelling periods and aggregation of larvae in a convergence zone northwest of Cabo Villano. C1 INST ESPANOL OCEANOG,LA CORUNA,SPAIN. OLD DOMINION UNIV,DEPT OCEANOG,NORFOLK,VA 23529. INST ESPANOL OCEANOG,VIGO,SPAIN. INST ESPANOL OCEANOG,FUENGIROLA,SPAIN. LOUISIANA UNIV MARINE CONSORTIUM,CHAUVIN,LA. SKIDAWAY INST OCEANOG,SAVANNAH,GA. NASA,GODDARD SPACE FLIGHT CTR,OCEANS LAB,GREENBELT,MD 20771. UNIV MARYLAND,CEES,HORN POINT ENVIRONM LAB,CAMBRIDGE,MD 21613. INST ESPANOL OCEANOG,MADRID,SPAIN. UNIV RHODE ISL,GRAD SCH OCEANOG,KINGSTON,RI 02882. RP TENORE, KR (reprint author), UNIV MARYLAND,CTR ENVIRONM & ESTUARINE STUDIES,CHESAPEAKE BIOL LAB,POB 38,SOLOMONS,MD 20688, USA. RI roman, michael/F-9425-2013; Miranda, Ana/L-2682-2014 OI Miranda, Ana/0000-0003-4872-0632 NR 42 TC 86 Z9 88 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1995 VL 100 IS C6 BP 10943 EP 10966 DI 10.1029/95JC00529 PG 24 WC Oceanography SC Oceanography GA RD775 UT WOS:A1995RD77500023 ER PT J AU HURWITZ, FI KACIK, TA BU, XY MASNOVI, J HEIMANN, PJ BEYENE, K AF HURWITZ, FI KACIK, TA BU, XY MASNOVI, J HEIMANN, PJ BEYENE, K TI PYROLYTIC CONVERSION OF METHYLSILANE AND VINYLSILANE POLYMERS TO SI-C CERAMICS SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID POLYCARBOSILAZANE PRECURSORS; N CERAMICS; SILICON-CARBIDE; MONOFILAMENTS; POLY(CARBOSILANE) AB Poly(methylsilane) and poly(vinylsilane) were synthesized using a titanocene catalyst, and their pyrolytic conversion to ceramics was followed using a combination of thermal analysis and infrared spectroscopy. The two polymers have distinctly different backbone structures, as determined by Si-29 NMR; methylsilane polymerizes to a polysilane, while vinylsilane polymers have a predominately polycarbosilane backbone, with some polysilane structure as well. The pyrolysis path and char yield were dependent primarily on backbone structure, with little influence of polymer molecular weight. The majority of the weight loss on conversion occurs below 650 degrees C, although bond rearrangement continues to 1400 degrees C. Poly (vinylsilane) produced a carbon-rich Si-C ceramic in which the carbon was dispersed on a sufficiently fine level to show resistance to oxidation on heating in air to 1400 degrees C. Copolymerization of methyl- and vinylsilane produced stoichiometric SiC; however, polymers of methylsilane were sensitive to oxygen incorporation and sometimes pyrophoric. Polymerization of vinylsilane with disilylethane permitted control of theology and imparted thermoset behaviour. C1 CLEVELAND STATE UNIV,CLEVELAND,OH 44115. RP HURWITZ, FI (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 25 TC 44 Z9 47 U1 1 U2 10 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 JUN 15 PY 1995 VL 30 IS 12 BP 3130 EP 3136 DI 10.1007/BF01209227 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA RG756 UT WOS:A1995RG75600017 ER PT J AU WISE, L AF WISE, L TI DEATH OF A HERO, BIRTH OF THE SOUL - ANSWERING THE CALL OF MIDLIFE - ROBINSON,JC SO LIBRARY JOURNAL LA English DT Book Review RP WISE, L (reprint author), NASA,CTR AEROSPACE INFORMAT,BALTIMORE,MD, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD JUN 15 PY 1995 VL 120 IS 11 BP 85 EP 86 PG 2 WC Information Science & Library Science SC Information Science & Library Science GA RC370 UT WOS:A1995RC37000147 ER PT J AU WISE, L AF WISE, L TI NOBODYS VICTIM - FREEDOM FROM THERAPY AND RECOVERY - MCCULLOUGH,CJ SO LIBRARY JOURNAL LA English DT Book Review RP WISE, L (reprint author), NASA,CTR AEROSPACE INFORMAT,BALTIMORE,MD, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD JUN 15 PY 1995 VL 120 IS 11 BP 85 EP 85 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA RC370 UT WOS:A1995RC37000144 ER PT J AU JOSLIN, SM CHEN, XF OLIVER, BF NOEBE, RD AF JOSLIN, SM CHEN, XF OLIVER, BF NOEBE, RD TI FRACTURE-BEHAVIOR OF DIRECTIONALLY SOLIDIFIED NIAL-MO AND NIAL-V EUTECTICS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE FRACTURE; SOLIDIFICATION; NICKEL; ALUMINUM; MOLYBDENIUM; VANDIUM AB A rod eutectic, Ni-45.45at.%Al-9at.%Mo, and a lamellar eutectic, Ni-30at.%Al-40at.%V, were directionally solidified by the containerless electromagnetically levitated zone (CELZ) process. Four-point bend tests were used to determine the fracture toughness of the CELZ processed eutectic alloys, while scanning electron microscopy and transmission eletron microscopy of tested samples were used to characterize the fracture behavior. The composite structures of these alloys provide improvement in fracture toughness over binary NiAl primarily by crack bridging and trapping for NiAl-9at.%Mo, and crack bridging and renucleation for NiAl-40at.%V. Significant plastic deformation of the NiAl phase prior to fracture also contributes to the toughness of both eutectic systems. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP JOSLIN, SM (reprint author), UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996, USA. NR 16 TC 26 Z9 27 U1 2 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD JUN 15 PY 1995 VL 196 IS 1-2 BP 9 EP 18 DI 10.1016/0921-5093(94)09683-X PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA RE690 UT WOS:A1995RE69000002 ER PT J AU MISRA, AK BOWMAN, RR AF MISRA, AK BOWMAN, RR TI THERMAL CYCLING RESPONSE AND OXIDATION BEHAVIOR OF AL2O3/NIAL COMPOSITES WITH INTERFACIAL MO COATING SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE THERMAL CYCLING; OXIDATION; AL2O3/NIAL COMPOSITES; MO COATING ID ALLOYS AB Thermal cycling response and oxidation behavior of Al2O3/NiAl composites with interfacial Mo coating were studied and results compared with that for weakly bonded composites without any interfacial coating. Thermal cycling of composites with interfacial Mo coating from room temperature to 1300 K in an inert atmosphere resulted in interfacial debonding along the Mo-Al2O3 interface, with the extent of debonding increasing with number of thermal cycles. Both isothermal and cyclic oxidation of composites with interfacial Mo coating at 1373 K resulted in a thick, dense Al2O3 scale along the fiber-matrix interface near the fiber ends. The depth of interfacial oxide penetration was confined to a short distance (about 100 mu m) from the fiber ends, with the rest of the composite intact. This is in contrast to the oxidation behavior of weakly bonded composites without any interfacial coating, in which oxidation along the fiber-matrix interface occurred throughout the composite, not just near the fiber ends. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP MISRA, AK (reprint author), NYMA INC,BROOKPARK,OH 44142, USA. NR 12 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD JUN 15 PY 1995 VL 196 IS 1-2 BP 197 EP 204 DI 10.1016/0921-5093(94)09695-3 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA RE690 UT WOS:A1995RE69000025 ER PT J AU MISHCHENKO, MI HOVENIER, JW AF MISHCHENKO, MI HOVENIER, JW TI DEPOLARIZATION OF LIGHT BACKSCATTERED BY RANDOMLY ORIENTED NONSPHERICAL PARTICLES SO OPTICS LETTERS LA English DT Article ID SCATTERING AB We derive theoretically and validate numerically general relationships for the elements of the backscattering matrix and for the linear, delta(L), and circular, delta(C), backscattering depolarization ratios for nonspherical particles in random orientation. For the practically important case of randomly oriented particles with a plane of symmetry or particles and their mirror particles occurring in equal numbers and in random orientation, delta(C) = 2 delta(L)/(1 - delta(L)) Extensive T-matrix computations for randomly oriented spheroids demonstrate that, although both delta(L) and delta(C) are indicators of particle nonsphericity, they cannot be considered a universal measure of the departure of particle shape from that of a sphere and have no simple dependence on particle size and refractive index. C1 FREE UNIV AMSTERDAM,DEPT PHYS & ASTRON,1081 HV AMSTERDAM,NETHERLANDS. RP MISHCHENKO, MI (reprint author), NASA,GODDARD INST SPACE STUDIES,SCI SYST & APPLICAT INC,2880 BROADWAY,NEW YORK,NY 10025, USA. RI Mishchenko, Michael/D-4426-2012 NR 14 TC 148 Z9 150 U1 0 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUN 15 PY 1995 VL 20 IS 12 BP 1356 EP & DI 10.1364/OL.20.001356 PG 0 WC Optics SC Optics GA RD232 UT WOS:A1995RD23200002 PM 19862013 ER PT J AU GRAZIANI, C HARDING, AK SINA, R AF GRAZIANI, C HARDING, AK SINA, R TI ELIMINATION OF RESONANT DIVERGENCES FROM QED IN SUPERSTRONG MAGNETIC-FIELDS SO PHYSICAL REVIEW D LA English DT Article ID GAMMA-RAY BURSTS; PAIR ANNIHILATION; CYCLOTRON EMISSION; COMPTON-SCATTERING; NEUTRON-STARS; ONE-PHOTON; LINE; ABSORPTION; PLASMAS C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. RP GRAZIANI, C (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. RI Harding, Alice/D-3160-2012 NR 33 TC 18 Z9 18 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 JUN 15 PY 1995 VL 51 IS 12 BP 7097 EP 7110 DI 10.1103/PhysRevD.51.7097 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA RE671 UT WOS:A1995RE67100048 ER PT J AU REID, JS LIU, RY SMITH, PM RUIZ, RP NICOLET, MA AF REID, JS LIU, RY SMITH, PM RUIZ, RP NICOLET, MA TI W-B-N DIFFUSION-BARRIERS FOR SI/CU METALLIZATIONS SO THIN SOLID FILMS LA English DT Article DE AMORPHOUS MATERIAL; CONTACTS; COPPER; DIFFUSION ID CU; STABILITY; TANTALUM; SILICON; SI; PERFORMANCE; COPPER; TA AB Reactively sputtered from a W2B target, amorphous W-B-N thin films are investigated. The physical properties of the films, namely density, resistivity, crystallization behavior and reaction temperature with silicon, are given as functions of composition. Additionally, the films are assessed as diffusion barriers between silicon substrates and copper overlays. By I(V) measurements of shallow-junction diodes, a 100 nm W64B20N16 barrier prevents copper from reaching the silicon during an 800 degrees C, 30 min heat treatment in vacuum. W79B21 films are able to prevent diffusion into the diodes only up to 500 degrees C. High resolution transmission electron microscopy shows that W64B20N16 and W79B21 films are both marginally amorphous with local ordering of less than 1.5 nm. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP REID, JS (reprint author), CALTECH,PASADENA,CA 91125, USA. NR 28 TC 37 Z9 41 U1 3 U2 5 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 JUN 15 PY 1995 VL 262 IS 1-2 BP 218 EP 223 DI 10.1016/0040-6090(94)05810-5 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA RJ842 UT WOS:A1995RJ84200027 ER PT J AU THAKOOR, S THAKOOR, AP AF THAKOOR, S THAKOOR, AP TI OPTICALLY ADDRESSED FERROELECTRIC MEMORY WITH NONDESTRUCTIVE READOUT SO APPLIED OPTICS LA English DT Article ID THIN-FILM CAPACITORS; HIGH-SPEED; HIGH-POWER; GROWTH; GAAS; MGO AB We present a review of the emerging optically addressed ferroelectric memory with nondestructive readout as a nonvolatile memory technology, identify its high-impact applications, and project on some novel device designs and architectures that will enable its realization. Based on the high-speed bidirectional polarization-dependent photoresponse, simulation of a readout circuit for a 16-kbit VLSI ferromemory chip yields read-access times of similar to 20 ns and read-cycle times of similar to 30 ns (similar to 34 ns and similar to 44 ns, respectively, within a framework of a radiation-hard environment), easily surpassing those of the conventional electrical destructive readout. Extension of the simulation for a 64-kbit memory shows that the read-access and -cycle times are only marginally increased to similar to 21 ns and similar to 31 ns, respectively (similar to 38 ns and similar to 48 ns, with a radiation-hard readout circuitry). Commercial realization of the optical nondestructive readout, however, would require a reduction in the incident (optical) power by roughly an order of magnitude for the readout or an enhancement in the delivered power-to-size ratio of semiconductor lasers for compact implementation. We present a new two-capacitor memory-cell configuration that provides an enhanced bipolar optoelectronic response from the edges of the capacitor at incident power as low as similar to 2 mW/mu m(2). A novel device design based on lead zirconate titanate with the c axis parallel to the substrate is suggested to reduce the requirement of incident optical power further by orders of magnitude. RP THAKOOR, S (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 40 TC 3 Z9 3 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JUN 10 PY 1995 VL 34 IS 17 BP 3136 EP 3144 PG 9 WC Optics SC Optics GA RB633 UT WOS:A1995RB63300012 PM 21052469 ER PT J AU CONTOPOULOS, J AF CONTOPOULOS, J TI FORCE-FREE SELF-SIMILAR MAGNETICALLY DRIVEN RELATIVISTIC JETS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, JETS; MHD; RELATIVITY; STARS, MASS LOSS ID HYDROMAGNETIC FLOWS; WINDS; OBJECTS; DISKS AB We present a class of self-similar solutions which represent force-free, axisymmetric, special relativistic, ideal, magnetohydrodynamic, collimated outflows (jets) from magnetized accretion disks around compact objects. The solutions extend to large distances beyond the light cylinder, and capture many of the important processes of how acceleration present in more general non-force-free solutions. We show that the important factor which determines the general morphology (degree of collimation) and the asymptotic Lorentz factor of the outflow is the distribution and total amount of electric current which hows along the jet. The present work makes the connection between the works of Li, Chiueh, & Begelman (1992) and Contopoulos (1994). RP CONTOPOULOS, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 665,GREENBELT,MD 20771, USA. NR 19 TC 40 Z9 40 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1995 VL 446 IS 1 BP 67 EP 74 DI 10.1086/175768 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF810 UT WOS:A1995RF81000008 ER PT J AU SKIBO, JG DERMER, CD RAMATY, R MCKINELY, JM AF SKIBO, JG DERMER, CD RAMATY, R MCKINELY, JM TI THERMAL COMPTONIZATION IN MILDLY RELATIVISTIC PAIR PLASMAS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, NUCLEI; GALAXIES, SEYFERT; PLASMAS; RADIATION MECHANISMS, NONTHERMAL; RELATIVITY ID ACTIVE GALACTIC NUCLEI; ELECTRON-POSITRON BREMSSTRAHLUNG; X-RAY; SPECTRAL VARIABILITY; GALAXIES; EQUILIBRIUM; LUMINOSITY; CYGNUS-X-1; REFLECTION; RADIATION AB We use a Monte Carlo simulation to calculate the spectra of mildly relativistic thermal plasmas in pair balance. We use the exact integral expression for the electron-positron thermal annihilation spectrum and provide accurate expressions for the Gaunt factors of electron-ion, electron-electron, and electron-positron thermal bremsstrahlung in the transrelativistic temperature regime. The particles are assumed to be uniformly distributed throughout a sphere, and the pair opacity is self-consistently calculated from the energy and angular distribution of scattered photons. The resultant photon spectra are compared with the nonrelativistic diffusion treatment of Sunyaev and Titarchuk, the bridging formulas of Zdziarski, and the relativistic corrections proposed by Titarchuk. We give a corrected formula for the spectral index resulting from Comptonization in the low-temperature, low optical depth regime, and show where the effects of bremsstrahlung production are important in spectral calculations. We calculate allowed pair-balanced states of thermal plasmas with no pair escape which include bremsstrahlung and internal soft photons. The results are presented in the spectral index/compactness plane and can be directly compared with observations of spectra from AGNs and Galactic black hole candidates. By comparing with X-ray spectral indices of Seyfert AGNs and compactnesses inferred from X-ray variability data, we find that the allowed solutions for pair equilibrium plasma imply that the temperatures of Seyfert galaxies are less than or similar to 300 keV. This prediction can be tested with more sensitive gamma-ray observations of Seyfert galaxies. We find that if the X-ray variability timescale gives an accurate measure of the compactness, pair-dominated solutions are inconsistent with the data. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. RP SKIBO, JG (reprint author), USN, RES LAB, EO HULBURT CTR SPACE RES, CODE 7653, WASHINGTON, DC 20375 USA. NR 57 TC 25 Z9 25 U1 0 U2 1 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 JUN 10 PY 1995 VL 446 IS 1 BP 86 EP 100 DI 10.1086/175770 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF810 UT WOS:A1995RF81000010 ER PT J AU COLBERT, EJM PETRE, R SCHLEGEL, EM RYDER, SD AF COLBERT, EJM PETRE, R SCHLEGEL, EM RYDER, SD TI SOFT-X-RAY EMISSION FROM THE SPIRAL GALAXY NGC-1313 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (NGC 1313); GALAXIES, SPIRAL; SUPERNOVAE, INDIVIDUAL (SN 1978K); X-RAYS, GALAXIES ID LARGE MAGELLANIC CLOUD; SOUTHERN GALAXIES; SUPERNOVA; REMNANTS; NGC-1313; SPECTRUM; M33 AB The nearby barred spiral galaxy NGC 1313 has been observed with the PSPC instrument on board the ROSAT X-ray satellite. Ten individual sources are found. Three sources (X-1, X-2, and X-3 [SN 1978K]) are very bright (similar to 10(40) ergs s(-1)) and are unusual in that analogous objects do not exist in our Galaxy. We present an X-ray image of NGC 1313 and X-ray spectra for the three bright sources. The emission from the nuclear region (R less than or similar to 2 kpc) is dominated by source X-1, which is located similar to 1 kpc north of the photometric (and dynamical) center of NGC 1313. Optical, far-infrared, and radio images do not indicate the presence of an active galactic nucleus at that position; however, the compact nature of the X-ray source (X-1) suggests that it is an accretion-powered object with central mass M greater than or similar to 10(3) M.. Additional emission (L(x) similar to 10(39) ergs s(-1)) in the nuclear region extends out to similar to 2.6 kpc and roughly follows the spiral arms. This emission is from four sources with luminosity of several x 10(38) ergs s(-1) two of which are consistent with emission from Population I sources (e.g., supernova remnants, and hot interstellar gas which has been heated by supernova remnants). The other two sources could be emission from Population II sources (e.g., low-mass X-ray binaries). The bright sources X-2 and SN 1978K are positioned in the southern disk of NGC 1313. X-2 is variable and has no optical counterpart brighter than 20.8 mag (V-band). It is likely that it is an accretion-powered object in NGC 1313. The Type II supernova SN 1978K (Ryder et al. 1993) has become extraordinarily luminous in X-rays similar to 13 yr after optical maximum. C1 UNIV MARYLAND, DEPT ASTRON, COLLEGE PK, MD 20742 USA. NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, XRAY ASTRON BRANCH, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. UNIV ALABAMA, DEPT PHYS & ASTRON, TUSCALOOSA, AL 35487 USA. OI Ryder, Stuart/0000-0003-4501-8100 NR 53 TC 44 Z9 44 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 JUN 10 PY 1995 VL 446 IS 1 BP 177 EP 193 DI 10.1086/175777 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF810 UT WOS:A1995RF81000017 ER PT J AU LI, P HURLEY, K FISHMAN, GJ KOUVELIOTOU, C HARTMANN, D AF LI, P HURLEY, K FISHMAN, GJ KOUVELIOTOU, C HARTMANN, D TI A SEARCH FOR STELLAR FLARES IN GAMMA-RAY BURSTS OBSERVED BY BATSE AND ULYSSES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS; STARS, FLARE ID HARD X-RAY; SOLAR-FLARES; AU MICROSCOPII; EMISSION; STARS AB We have searched for gamma-ray bursts during stellar flares using Ulysses and BATSE/CGRO data and for a correlation between flare star positions and burst positions. More than 3000 stellar flares have been identified optically, but neither BATSE nor Ulysses observed any gamma-ray bursts which could be attributed to them. Using the BATSE trigger threshold, and the known distances to these flare stars, upper limits to the gamma-ray luminosity were obtained. We have also studied the conditions under which stellar flares could be detected by BATSE as weak GRBs. We found that if some weak events (10(-7) ergs cm(-2) s(-1)) are to be explained by flares as recently suggested, the X-ray emission (>25 keV) must be comparable to the stellar optical emission, and the ratio of L(x)/L(opt) must be higher than that for solar hares by at least four orders of magnitude. The stellar flare log N-log S and spatial distributions are studied and their implications for gamma-ray bursts are discussed. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. RP LI, P (reprint author), UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720, USA. NR 58 TC 3 Z9 3 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1995 VL 446 IS 1 BP 267 EP 271 DI 10.1086/175785 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF810 UT WOS:A1995RF81000025 ER PT J AU JOHANSSON, S BRAGE, T LECKRONE, DS NAVE, G WAHLGREN, GM AF JOHANSSON, S BRAGE, T LECKRONE, DS NAVE, G WAHLGREN, GM TI INTERPRETATION OF ANOMALOUS ULTRAVIOLET TRANSITIONS OF FE-II OBSERVED IN LABORATORY FOURIER-TRANSFORM SPECTRA AND STELLAR HST AND IUE SPECTRA SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC PROCESSES; LINE, IDENTIFICATION; METHODS, LABORATORY STARS, INDIVIDUAL (CHI LUPI, 32 CYGNI); ULTRAVIOLET, STARS ID B-STAR; LINES AB We discuss LS-forbidden Delta S = 2 transitions of Fe Pi that appear as strong lines in ultraviolet stellar and laboratory spectra. The lines occur because of indirect lever mixing-two close energy levels, w(2)P(3/2) and x(6)P(3/2), are mixed through a third level acting as a catalyst. In transition multiplets, that involve either the w(2)P(3/2) or the x(6)P(3/2) level the normal component is accompanied by a close, parasite component. These components are well resolved in laboratory Fourier transform spectra, from which accurate intensity ratios can be measured. Spectra of the HgMn star chi Lupi, recorded with the Hubble Space Telescope, show the normal and the parasite components resolved for the first time in stellar spectra. These have been used together with laboratory spectra to derive oscillator strengths for four multiplets and the mixing coefficients for the two interacting energy levels. We also provide improved spectroscopic data for all Fe Pi multiplets that include the w(2)P(3/2) and x(6)P(3/2) levels. The level mixing involves the UV 191 multiplet of Fe Pi around 1780 Angstrom, which is shown to have one parasite component. This multiplet is known to be a prominent emission feature in spectra of various objects, e.g., cool star chromospheres and symbiotic stars. As an example, we show IUE spectra of the eclipsing binary 32 Cyg, which provides perfect conditions for fluorescence experiments, and discuss possible excitation mechanisms of UV 191. Based on second-order perturbation theory and multiconfiguration Hartree-Fock calculations, an atomic three-level model is constructed. This model explains the contradiction found when applying first-order perturbation theory, viz., two close energy levels perturbing each other without causing a repulsion. C1 NIST,DIV ATOM PHYS,GAITHERSBURG,MD 20899. NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP & GHRS SCI TEAM,ASTRON PROGRAM,GREENBELT,MD 20771. LUND UNIV,DEPT PHYS,S-22362 LUND,SWEDEN. RP JOHANSSON, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 681,GREENBELT,MD 20771, USA. OI Brage, Tomas/0000-0003-3985-767X NR 25 TC 19 Z9 19 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1995 VL 446 IS 1 BP 361 EP 370 DI 10.1086/175795 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF810 UT WOS:A1995RF81000035 ER PT J AU MEEGAN, CA HARTMANN, DH BRAINERD, JJ BRIGGS, MS PACIESAS, WS PENDLETON, G KOUVELIOTOU, C FISHMAN, G BLUMENTHAL, G BROCK, M AF MEEGAN, CA HARTMANN, DH BRAINERD, JJ BRIGGS, MS PACIESAS, WS PENDLETON, G KOUVELIOTOU, C FISHMAN, G BLUMENTHAL, G BROCK, M TI DO GAMMA-RAY BURST SOURCES REPEAT SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS AB The demonstration of repeated gamma-ray bursts from an individual source would severely constrain burst source models. Recent reports (Quashnock and Lamb 1993; Wang and Lingenfelter 1993) of evidence for repetition in the first BATSE burst catalog have generated renewed interest in this issue. Here, we analyze the angular distribution of 585 bursts of the second BATSE catalog (Meegan et al. 1994). We search for evidence of burst recurrence using the nearest and farthest neighbor statistic and the two-point angular correlation function. We find the data to be consistent with the hypothesis that burst sources do not repeat; however, a repeater fraction of up to about 20% of the observed bursts cannot be excluded. C1 CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. UNIV CALIF SANTA CRUZ,UNIV CALIF OBSERV,LICK OBSERV,SANTA CRUZ,CA 95064. RP MEEGAN, CA (reprint author), NASA,MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35899, USA. NR 23 TC 24 Z9 24 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 10 PY 1995 VL 446 IS 1 BP L15 EP L18 DI 10.1086/187919 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF811 UT WOS:A1995RF81100004 ER PT J AU RISTORCELLI, JR LUMLEY, JL ABID, R AF RISTORCELLI, JR LUMLEY, JL ABID, R TI A RAPID-PRESSURE COVARIANCE REPRESENTATION CONSISTENT WITH THE TAYLOR-PROUDMAN THEOREM MATERIALLY FRAME INDIFFERENT IN THE 2-DIMENSIONAL LIMIT SO JOURNAL OF FLUID MECHANICS LA English DT Article ID EQUILIBRIUM STATES; SHEARED TURBULENCE; STRAIN CORRELATION; ROTATING FRAME; CHANNEL FLOW; SIMULATIONS AB A nonlinear variable-coefficient representation for the rapid-pressure covariance appearing in the Reynolds stress and heat-flux equations, consistent with the Taylor-Proudman theorem, is presented. The representation ensures that the modelled second-order equations are frame indifferent with respect to rotation in a number of different flows for which such an invariance is required. The model coefficients are functions of the state of the turbulence; they are valid for all states of a mechanical turbulence, attaining their limiting values only when the limit state is achieved. This is accomplished by a special ansatz that is used to obtain - analytically - the coefficients valid away from the realizability limit. Unlike other rapid-pressure representations in which extreme states are used to set model constants, here the coefficients are variable functions asymptotically consisted with-not fixed by-the limit states of the turbulence field. The mathematical principles invoked do not specify all the coefficients in the model; undetermined coefficients appear as free parameters which are used to ensure that the representation is asymptotically consistent with an experimentally determined equilibrium state of homogeneous sheared turbulence. This is done by ensuring that the modelled evolution equations have the same fixed points as those obtained from numerical and laboratory experiments for the homogeneous shear. Results of computations of homogeneous shear, with rotation and with curvature, are shown. Results are better, in a wide class of planar flows for which the model has not been calibrated, than those of other nonlinear models. C1 CORNELL UNIV,SIBLEY SCH MECH & AEROSP ENGN,ITHACA,NY 14850. NASA,LANGLEY RES CTR,HIGH TECHNOL CORP,HAMPTON,VA 23681. RP RISTORCELLI, JR (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23681, USA. NR 42 TC 41 Z9 41 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 JUN 10 PY 1995 VL 292 BP 111 EP 152 DI 10.1017/S0022112095001467 PG 42 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RF328 UT WOS:A1995RF32800006 ER PT J AU VOORHIES, CV AF VOORHIES, CV TI TIME-VARYING FLUID-FLOW AT THE TOP OF EARTHS CORE DERIVED FROM DEFINITIVE GEOMAGNETIC REFERENCE FIELD MODELS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID MANTLE BOUNDARY; SURFACE; MOTIONS; APPROXIMATION AB The effects of a time-varying fluid velocity have been included in the estimation of frozen-flux core surface flow. This has been done to improve the quality, performance, and accuracy of kinematic analyses of the geomagnetic secular variation. The derived flows consist of a reference velocity plus a steady acceleration and thus evolve linearly with time. The method features simultaneous solution for the initial radial geomagnetic field component at the core-mantle boundary and the subadjacent, time-varying fluid motion. The trade-off between time-averaged spatial complexity of the derived flows and misfit to the weighted Definitive Geomagnetic Reference Field models for 1945-1980 is explored. At fixed flow complexity, simultaneous solution for both initial geomagnetic field and steadily accelerating flow gives substantial reductions in the square-weighted residuals per degree of freedom when compared with previous solutions for either initial field and steady flow or steady flow alone. The apparent timescale for flow change varies nonmonotonically with flow complexity between about 23 and 41 years; the single maximum value is associated with unit negative slope of the log-log trade-off curve and is used to help identify a preferred solution. This solution has an rms speed of but 7.50 km yr(-1) and an rms acceleration of 0.183 km yr(-2), or 1.84x10(-13) m s(-2). The latter indicates extremely weak net forces upon the liquid outer core. RP VOORHIES, CV (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GEODYNAM BRANCH, CODE 921, GREENBELT, MD 20771 USA. RI Voorhies, Coerte/D-4672-2012 NR 39 TC 20 Z9 21 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JUN 10 PY 1995 VL 100 IS B6 BP 10029 EP 10039 DI 10.1029/95JB00863 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RC486 UT WOS:A1995RC48600018 ER PT J AU VISSCHER, L DYALL, KG AF VISSCHER, L DYALL, KG TI MP2 STUDIES OF RELATIVISTIC EFFECTS ON THE LINEAR STATIONARY-POINTS OF THE H+CL-2-]HCL+CL AND CL+HCL-]CLH+CL REACTIONS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; ELECTRONIC-STRUCTURE CALCULATIONS; GAUSSIAN-BASIS SETS; ABINITIO; CLHCL AB The influence of relativistic effects on the linear stationary points of the potential energy surfaces of the CIHCl and HCl2 systems is studied. Scalar relativistic effects have little influence on the geometries and the energies at these points. Spin-orbit effects have no influence on the barrier of the forward reaction of H with Cl-2, but increase the reaction energy. The total relativistic effect is an increase of the reaction energy by 2.3 kJ mol(-1). The barrier for the iso-energetic exchange reaction of HCl with Cl is decreased by 0.5 kJ mol(-1) due to the scalar relativistic effects. This small decrease is cancelled by the larger increase of 2.5 kJ mol(-1) due to spin-orbit effects, giving a total relativistic effect of 2.0 kJ mol(-1). RP VISSCHER, L (reprint author), NASA,AMES RES CTR,MAIL STOP 230-3,MOFFETT FIELD,CA 94035, USA. RI Visscher, Lucas/A-3523-2010 OI Visscher, Lucas/0000-0002-7748-6243 NR 27 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 9 PY 1995 VL 239 IS 1-3 BP 181 EP 185 DI 10.1016/0009-2614(95)00435-7 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RD863 UT WOS:A1995RD86300030 ER PT J AU JEANLOZ, R MITCHELL, DL SPRAGUE, AL DEPATER, I AF JEANLOZ, R MITCHELL, DL SPRAGUE, AL DEPATER, I TI EVIDENCE FOR A BASALT-FREE SURFACE ON MERCURY AND IMPLICATIONS FOR INTERNAL HEAT SO SCIENCE LA English DT Article ID THERMAL EVOLUTION; ATMOSPHERE; POTASSIUM; MANTLE; PLANETS; SODIUM AB Microwave and mid-infrared observations reveal that Mercury's surface contains less FeO + TiO2 and at least as much feldspar as the lunar highlands. The results are compatible with the high albedo (brightness) of Mercury's surface at visible wavelengths in suggesting a rock and soil composition that is devoid of basalt, the primary differentiate of terrestrial mantles. The occurrence of a basalt-free, highly differentiated crust is in accord with recent models of the planet's thermal evolution and suggests that Mercury has retained a hot interior as a result of a combination of inefficient mantle convection and minimal volcanic heat loss. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. RP JEANLOZ, R (reprint author), UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720, USA. NR 45 TC 66 Z9 66 U1 0 U2 5 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 9 PY 1995 VL 268 IS 5216 BP 1455 EP 1457 DI 10.1126/science.7770770 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RC190 UT WOS:A1995RC19000027 PM 7770770 ER PT J AU GREEN, S PAN, BY BOWMAN, JM AF GREEN, S PAN, BY BOWMAN, JM TI QUANTUM SCATTERING CALCULATIONS FOR VIBRATIONAL AND ROTATIONAL-EXCITATION OF CO BY HOT HYDROGEN-ATOMS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISCRETE VARIABLE REPRESENTATION; EXCIMER LASER PHOTOLYSIS; H+CO REVERSIBLE HCO; H + CO; COLLISIONAL EXCITATION; S-MATRIX; ENERGY-TRANSFER; MOLECULES; SYSTEM; DISTRIBUTIONS C1 EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322. EMORY UNIV,CHERRY L EMERSON CTR SCI COMPUTAT,ATLANTA,GA 30322. RP GREEN, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 46 TC 14 Z9 14 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 1995 VL 102 IS 22 BP 8800 EP 8806 DI 10.1063/1.468933 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA RC468 UT WOS:A1995RC46800012 ER PT J AU OSTRO, SJ ROSEMA, KD HUDSON, RS JURGENS, RF GIORGINI, JD WINKLER, R YEOMANS, DK CHOATE, D ROSE, R SLADE, MA HOWARD, SD MITCHELL, DL AF OSTRO, SJ ROSEMA, KD HUDSON, RS JURGENS, RF GIORGINI, JD WINKLER, R YEOMANS, DK CHOATE, D ROSE, R SLADE, MA HOWARD, SD MITCHELL, DL TI EXTREME ELONGATION OF ASTEROID 1620-GEOGRAPHOS FROM RADAR IMAGES SO NATURE LA English DT Article ID GALILEO PHYSICAL MODEL; CATASTROPHIC COLLISIONS; IMPACT EXPERIMENTS; FRAGMENTATION AB Most small asteroids are thought to result from catastrophic collisions(1), and their shapes can provide insight into their origin and collisional evolution. Two main-belt asteroids have been successfully imaged by spacecraft(2,3), but such images have yet to be obtained for asteroids that cross Earth's orbit. Earth-crossing asteroids are generally too small to be resolved by optical telescopes, and shape constraints derived from optical lightcurves are subject to large systematic biases(4). Ground-based radar observations, on the other hand, have proved successful in resolving the shapes of some small asteroids(5-9). We describe here radar measurements of the Earth-crossing asteroid 1620 Geographos during its recent close encounter with the Earth. We have determined the silhouette of Geographos along its rotation axis, and confirm earlier lightcurve-based conjectures(10) that this object has a very unusual shape. The silhouette is irregular, non-convex and has an aspect ratio of 2.76 +/- 0.21, establishing it as the most elongated Solar System object yet imaged, The unusual nature of the shape is underscored by laboratory fragmentation experiments(11,12), in which the average aspect ratio of fragments is 1.4, with fewer than 1% as elongated as Geographos. C1 WASHINGTON STATE UNIV,SCH ELECT ENGN & COMP SCI,PULLMAN,WA 99164. RP OSTRO, SJ (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 39 TC 34 Z9 34 U1 1 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JUN 8 PY 1995 VL 375 IS 6531 BP 474 EP 477 DI 10.1038/375474a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RC188 UT WOS:A1995RC18800043 ER PT J AU ROSE, WI DELENE, DJ SCHNELDER, DJ BLUTH, GJS KRUEGER, AJ SPROD, I MCKEE, C DAVIES, HL ERNST, GGJ AF ROSE, WI DELENE, DJ SCHNELDER, DJ BLUTH, GJS KRUEGER, AJ SPROD, I MCKEE, C DAVIES, HL ERNST, GGJ TI ICE IN THE 1994 RABAUL ERUPTION CLOUD - IMPLICATIONS FOR VOLCANO HAZARD AND ATMOSPHERIC EFFECTS SO NATURE LA English DT Article AB VOLCANIC clouds are an important natural hazard to aircraft(1), and host chemical reactions that interest both volcanologists(2,3) and atmospheric scientists(4-6). Ice has been suggested as a possible component of eruption clouds', but there has been no direct evidence for its presence. Here we report the detection, using a satellite-borne infrared sensor, of greater than or similar to 2 million tonnes of ice in the cloud produced by the September 1994 eruption of Rabaul volcano, in Papua New Guinea. The cloud also contained relatively low levels of sulphur dioxide (80+/-50 kilotonnes), compared with other stratospheric eruption clouds. The unusual aspects of this cloud may be related to the entry of sea water into the volcanic vent, and its participation in the eruption column. Past eruptions that occurred in similar (coastal) settings, such as those of Krakatau and Santorini, might have had less effect on the atmosphere than their volume alone would suggest, because the presence of ice may decrease the residence time of ash and sulphur in the atmosphere. In addition, the ability of ice to mask the characteristic spectral signature of volcanic ash will increase the difficulty of designing airborne ash detection systems for aviation safety. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RABAUL VOLCANO OBSERV,RABAUL,PAPUA N GUINEA. UNIV PAPUA NEW GUINEA,WAIGANI,PAPUA N GUINEA. UNIV BRISTOL,DEPT GEOL,BRISTOL BS8 1RJ,AVON,ENGLAND. RP ROSE, WI (reprint author), MICHIGAN TECHNOL UNIV,HOUGHTON,MI 49931, USA. RI Rose, William/A-7923-2009 NR 28 TC 97 Z9 99 U1 1 U2 10 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JUN 8 PY 1995 VL 375 IS 6531 BP 477 EP 479 DI 10.1038/375477a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RC188 UT WOS:A1995RC18800044 ER PT J AU BUSCH, R KIM, YJ JOHNSON, WL RULISON, AJ RHIM, WK ISHEIM, D AF BUSCH, R KIM, YJ JOHNSON, WL RULISON, AJ RHIM, WK ISHEIM, D TI HEMISPHERICAL TOTAL EMISSIVITY AND SPECIFIC-HEAT CAPACITY OF DEEPLY UNDERCOOLED ZR41.2TI13.8CU12.5NI10.0BE22.5 MELTS SO APPLIED PHYSICS LETTERS LA English DT Article ID ALLOYS; GLASS C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV GOTTINGEN,INST MET PHYS,D-37073 GOTTINGEN,GERMANY. RP BUSCH, R (reprint author), CALTECH,WM KECK LAB ENGN MAT,PASADENA,CA 91125, USA. RI Isheim, Dieter/B-7524-2009 NR 22 TC 59 Z9 59 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 5 PY 1995 VL 66 IS 23 BP 3111 EP 3113 DI 10.1063/1.113619 PG 3 WC Physics, Applied SC Physics GA RB347 UT WOS:A1995RB34700009 ER PT J AU OHSAKA, K TRINH, EH AF OHSAKA, K TRINH, EH TI ESTIMATION OF THE CONFIGURATIONAL ENTROPY OF FUSION SO APPLIED PHYSICS LETTERS LA English DT Article ID GLASS-TRANSITION; MODEL RP OHSAKA, K (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 7 TC 4 Z9 4 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 5 PY 1995 VL 66 IS 23 BP 3123 EP 3125 DI 10.1063/1.113623 PG 3 WC Physics, Applied SC Physics GA RB347 UT WOS:A1995RB34700013 ER PT J AU PELTZER, G ROSEN, P AF PELTZER, G ROSEN, P TI SURFACE DISPLACEMENTS OF THE 17 MAY 1993 EUREKA VALLEY, CALIFORNIA, EARTHQUAKE OBSERVED BY SAR INTERFEROMETRY SO SCIENCE LA English DT Article ID RADAR INTERFEROMETRY; DEFORMATION; SPACE AB Satellite synthetic aperture radar (SAR) interferometry shows that the magnitude 6.1 Eureka Valley earthquake of 17 May 1993 produced an elongated subsidence basin oriented north-northwest, parallel to the trend defined by the aftershock distribution, whereas the source mechanism of the earthquake implies a north-northeast-striking normal fault. The +/-3-millimeter accuracy of the radar-observed displacement map over short spatial scales allowed identification of the main surface rupture associated with the event. These observations suggest that the rupture began at depth and propagated diagonally upward and southward on a west-dipping, north-northeast fault plane, reactivating the largest escarpment in the Saline Range. RP PELTZER, G (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 15 TC 124 Z9 131 U1 1 U2 2 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JUN 2 PY 1995 VL 268 IS 5215 BP 1333 EP 1336 DI 10.1126/science.268.5215.1333 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA RB198 UT WOS:A1995RB19800034 PM 17778980 ER PT J AU MILLER, CG AF MILLER, CG TI MEASURING THE CONTINUUM SO AEROSPACE AMERICA LA English DT Article RP MILLER, CG (reprint author), NASA,LANGLEY RES CTR,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD JUN PY 1995 VL 33 IS 6 BP 24 EP 28 PG 5 WC Engineering, Aerospace SC Engineering GA RC481 UT WOS:A1995RC48100008 ER PT J AU HAAS, BL HASSAN, HA MOSS, JN ROCHELLE, WC AF HAAS, BL HASSAN, HA MOSS, JN ROCHELLE, WC TI SIMULATING RAREFIED AEROTHERMODYNAMICS SO AEROSPACE AMERICA LA English DT Article RP HAAS, BL (reprint author), NASA,AMES RES CTR,INST THERMOSCI,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 JUN PY 1995 VL 33 IS 6 BP 28 EP 31 PG 4 WC Engineering, Aerospace SC Engineering GA RC481 UT WOS:A1995RC48100009 ER PT J AU GOLDSTEIN, H HOFFMAN, W JOHNSON, W SMITH, M AF GOLDSTEIN, H HOFFMAN, W JOHNSON, W SMITH, M TI HIGH-TEMPERATURE MATERIALS GO THE DISTANCE SO AEROSPACE AMERICA LA English DT Article RP GOLDSTEIN, H (reprint author), NASA,AMES RES CTR,DIV SPACE TECHNOL,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 JUN PY 1995 VL 33 IS 6 BP 32 EP 35 PG 4 WC Engineering, Aerospace SC Engineering GA RC481 UT WOS:A1995RC48100010 ER PT J AU ARNONE, A LIOU, MS POVINELLI, LA AF ARNONE, A LIOU, MS POVINELLI, LA TI INTEGRATION OF NAVIER-STOKES EQUATIONS USING DUAL TIME-STEPPING AND A MULTIGRID METHOD SO AIAA JOURNAL LA English DT Article ID EULER EQUATIONS; FLOW AB Efficient acceleration techniques typical of explicit steady state solvers are extended to time accurate calculations. Stability restrictions are greatly reduced by means of a fully implicit time discretization. A four-stage Runge-Kutta scheme with local time stepping, residual smoothing, and multigridding is used instead of traditional computationally expensive factorizations. Two applications to natural unsteady viscous flows are presented to check for the capability of the procedure. C1 NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RP ARNONE, A (reprint author), UNIV FLORENCE,DEPT ENERGY ENGN,FLORENCE,ITALY. OI Arnone, Andrea/0000-0001-7471-4442 NR 17 TC 44 Z9 50 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 JUN PY 1995 VL 33 IS 6 BP 985 EP 990 DI 10.2514/3.12518 PG 6 WC Engineering, Aerospace SC Engineering GA RA332 UT WOS:A1995RA33200002 ER PT J AU KWON, OJ HAH, C AF KWON, OJ HAH, C TI SIMULATION OF 3-DIMENSIONAL TURBULENT FLOWS ON UNSTRUCTURED MESHES SO AIAA JOURNAL LA English DT Article ID EULER EQUATIONS; EPSILON AB A three-dimensional Navier-Stokes flow solver is developed on unstructured tetrahedral meshes. For a turbulence closure, a standard high-Reynolds-number k-epsilon model with a wall function boundary condition is used. The seven equations of motion are discretized and integrated in a tightly coupled manner. The time integration is achieved using an explicit Runge-Kutta time-stepping scheme. The inviscid Aux terms are discretized based on a cell-centered finite volume formulation with Roe's flux-difference splitting. The numerical method is applied for flows on a two-dimensional backward-facing step and a three-dimensional turbomachinery geometry. The results are compared with analytical and experimental data for validations. C1 NYMA INC,TURBOMACH ANAL SECT,BROOKPARK,OH 44142. NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135. RI KWON, OH JOON/C-1532-2011 NR 33 TC 7 Z9 7 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 JUN PY 1995 VL 33 IS 6 BP 1081 EP 1089 DI 10.2514/3.12822 PG 9 WC Engineering, Aerospace SC Engineering GA RA332 UT WOS:A1995RA33200015 ER PT J AU OBAYASHI, S GURUSWAMY, GP AF OBAYASHI, S GURUSWAMY, GP TI CONVERGENCE ACCELERATION OF A NAVIER-STOKES SOLVER FOR EFFICIENT STATIC AEROELASTIC COMPUTATIONS SO AIAA JOURNAL LA English DT Article ID EQUATIONS AB New capabilities have been developed for a Navier-Stokes solver to perform steady-state simulations more efficiently. The how solver for solving the Navier-Stokes equations is based on a combination of the lower-upper factored symmetric Gauss-Seidel implicit method and the modified Harten-Lax-van Leer-Einfeldt upwind scheme. A numerically stable and efficient pseudo-time-marching method is also developed for computing steady flows over flexible wings. Results are demonstrated for transonic flaws over rigid and flexible wings. C1 NASA,AMES RES CTR,APPL COMPUTAT AERODYNAM BRANCH,MOFFETT FIELD,CA 94035. NR 26 TC 94 Z9 99 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 JUN PY 1995 VL 33 IS 6 BP 1134 EP 1141 DI 10.2514/3.12533 PG 8 WC Engineering, Aerospace SC Engineering GA RA332 UT WOS:A1995RA33200022 ER PT J AU HECHT, H KAISER, MK AF HECHT, H KAISER, MK TI SPATIAL REPRESENTATION - EILAN,N, MCCARTHY,R, BREWER,B SO AMERICAN JOURNAL OF PSYCHOLOGY LA English DT Book Review RP HECHT, H (reprint author), NASA,AMES RES CTR,MAIL STOP 262-2,MOFFETT FIELD,CA 94035, USA. RI Hecht, Heiko/H-3106-2011 NR 7 TC 0 Z9 0 U1 0 U2 0 PU UNIV ILLINOIS PRESS PI CHAMPAIGN PA 1325 S OAK ST, CHAMPAIGN, IL 61820 SN 0002-9556 J9 AM J PSYCHOL JI Am. J. Psychol. PD SUM PY 1995 VL 108 IS 2 BP 283 EP 289 DI 10.2307/1423133 PG 7 WC Psychology, Multidisciplinary SC Psychology GA RH239 UT WOS:A1995RH23900007 ER PT J AU BISHU, RR KIM, B KLUTE, G AF BISHU, RR KIM, B KLUTE, G TI FORCE-ENDURANCE RELATIONSHIP - DOES IT MATTER IF GLOVES ARE DONNED SO APPLIED ERGONOMICS LA English DT Article DE GLOVES; EXERTION AND ENDURANCE LIMITS AB The human hand is a very useful multipurpose tool in all environments. However, performance capabilities are compromised considerably when gloves are donned. This is especially true for extra-vehicular activity (EVA) gloves used in a space environment. The primary aim of this study was to establish exertion and endurance limits for specific tasks. The objective of this study was to develop grip force endurance relations. Six subjects participated in a factorial experiment involving three hand conditions, three pressure differentials, and four levels of force exertion. The results indicate that while the force that could be exerted depended on the glove, pressure differential, and the level of exertion, the endurance time at any exertion level depended just on the level of exertion expressed as a percentage of maximum exertion possible at that condition, The impact of these findings for practitioners as well as theoreticians is discussed. C1 NASA,LYNDON B JOHNSON SPACE CTR,ANTHROPOMETRY & BIOMETRY LAB,HOUSTON,TX 77058. RP BISHU, RR (reprint author), UNIV NEBRASKA,DEPT IND ENGN,LINCOLN,NE 68588, USA. NR 15 TC 13 Z9 16 U1 0 U2 3 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA LINACRE HOUSE JORDAN HILL, OXFORD, OXON, ENGLAND OX2 8DP SN 0003-6870 J9 APPL ERGON JI Appl. Ergon. PD JUN PY 1995 VL 26 IS 3 BP 179 EP 185 DI 10.1016/0003-6870(95)00015-5 PG 7 WC Engineering, Industrial; Ergonomics; Psychology, Applied SC Engineering; Psychology GA RW323 UT WOS:A1995RW32300003 PM 15677016 ER PT J AU SITU, W DEYOUNG, RJ AF SITU, W DEYOUNG, RJ TI LONG-DISTANCE DETECTION OF LASER-PRODUCED IONS BY A REFLECTRON MASS-SPECTROMETER SO APPLIED SPECTROSCOPY LA English DT Article DE MASS SPECTROSCOPY; REMOTE LASER MASS SPECTROSCOPY; ANALYSIS OF SOLIDS; LASER ABLATION; REFLECTRON; LUNAR SIMULANT ID FLIGHT AB Laser-produced ions were detected and analyzed remotely by a reflectron mass spectrometer for determination of the elemental composition. Detection of ions at 3.9 m from the target was accomplished. Elemental and isotopic mass spectra of aluminum, germanium, copper, silver, and complex targets such as a lunar simulant and Standard Reference Material 1834 were mass-analyzed at 1 x 10(9) W/cm(2) (0.02 wt % detection limit), giving good correlation with manufacturers' stated elemental composition and yield. Mass spectra could be obtained in a single laser pulse. The mass resolution is 62 at mass 63 and 77 at mass 28. Such a system could be extended to a remote laser mass spectrometer on a lunar rover or satellite for planetary surface mass analysis. C1 OLD DOMINION UNIV,NORFOLK,VA 23529. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 15 TC 3 Z9 3 U1 2 U2 2 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JUN PY 1995 VL 49 IS 6 BP 791 EP 797 DI 10.1366/0003702953964525 PG 7 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA RG354 UT WOS:A1995RG35400013 ER PT J AU RODRIGUE, M SCHULTZ, A THOMPSON, J COLEGROVE, T SPIGHT, LD DISANTI, M FINK, U GRUNDY, W FRICKE, K PAPADEROS, P AF RODRIGUE, M SCHULTZ, A THOMPSON, J COLEGROVE, T SPIGHT, LD DISANTI, M FINK, U GRUNDY, W FRICKE, K PAPADEROS, P TI A MULTIWAVELENGTH INVESTIGATION OF THE MERGING GALAXY HCG 95C SO ASTRONOMICAL JOURNAL LA English DT Article ID COMPACT-GROUPS; SEYFERT-GALAXIES; STAR FORMATION; STARBURST GALAXIES; INFRARED-EMISSION; CLASSIFICATION; SPECTRA C1 STSCI,CSC,BALTIMORE,MD 21206. UNIV NEVADA,DEPT PHYS,RENO,NV 89557. UNIV NEVADA,DEPT PHYS,LAS VEGAS,NV 89154. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. UNIV STERNWARTE GOTTINGEN,GOTTINGEN,GERMANY. RP RODRIGUE, M (reprint author), UNIV NEVADA,DEPT PHYS,RENO,NV 89557, USA. RI Colegrove, Patrick/G-7386-2011; Papaderos, Polychronis/M-4206-2013 OI Colegrove, Patrick/0000-0002-7947-3067; Papaderos, Polychronis/0000-0002-3733-8174 NR 29 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 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2362 EP 2367 DI 10.1086/117456 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800005 ER PT J AU WEIR, N FAYYAD, UM DJORGOVSKI, S AF WEIR, N FAYYAD, UM DJORGOVSKI, S TI AUTOMATED STAR GALAXY CLASSIFICATION FOR DIGITIZED POSS-II SO ASTRONOMICAL JOURNAL LA English DT Article C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP WEIR, N (reprint author), CALTECH,PALOMAR OBSERV,105-24,PASADENA,CA 91125, USA. NR 29 TC 56 Z9 58 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2401 EP 2414 DI 10.1086/117459 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800008 ER PT J AU SCHLEGEL, EM AF SCHLEGEL, EM TI TEMPLATE SUPERNOVA LIGHT CURVES FOR THE R(C) AND I-C PHOTOMETRIC BANDS - SN IA AND SN IIP SO ASTRONOMICAL JOURNAL LA English DT Article ID SPECTROSCOPIC OBSERVATIONS; CCD PHOTOMETRY C1 UNIV SPACE RES ASSOC,GREENBELT,MD. RP SCHLEGEL, EM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 668,GREENBELT,MD 20771, USA. NR 34 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2620 EP 2626 DI 10.1086/117475 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800024 ER PT J AU DANKS, AC SEMBACH, KR AF DANKS, AC SEMBACH, KR TI HIGH-VELOCITY GAS IN THE VELA SUPERNOVA REMNANT SO ASTRONOMICAL JOURNAL LA English DT Article ID INTERSTELLAR NA-I; ABSORPTION-LINES; CA-II; STARS; SHOCK; HALO C1 MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. EUROPEAN SO OBSERV,LA SILLA,CHILE. RP DANKS, AC (reprint author), GODDARD SPACE FLIGHT CTR,HUGHES STX,CODE 683,GREENBELT,MD 20771, USA. NR 34 TC 36 Z9 36 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2627 EP 2634 DI 10.1086/117476 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800025 ER PT J AU LAWRENCE, SS MACALPINE, GM UOMOTO, A WOODGATE, BE BROWN, LW OLIVERSEN, RJ LOWENTHAL, JD LIU, C AF LAWRENCE, SS MACALPINE, GM UOMOTO, A WOODGATE, BE BROWN, LW OLIVERSEN, RJ LOWENTHAL, JD LIU, C TI 3-DIMENSIONAL FABRY-PEROT IMAGING SPECTROSCOPY OF THE CRAB-NEBULA, CASSIOPEIA-A, AND NOVA GK-PERSEI SO ASTRONOMICAL JOURNAL LA English DT Article ID SUPERNOVA REMNANT; INTERSTELLAR-MEDIUM; FILAMENTS; EJECTA; WAVE C1 JOHNS HOPKINS UNIV, DEPT PHYS & ASTRON, BALTIMORE, MD 21218 USA. GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV CALIF SANTA CRUZ, LICK OBSERV, SANTA CRUZ, CA 95064 USA. UNIV ARIZONA, DEPT ASTRON, TUCSON, AZ 85721 USA. RP UNIV MICHIGAN, DEPT ASTRON, ANN ARBOR, MI 48109 USA. RI Woodgate, Bruce/D-2970-2012 NR 72 TC 79 Z9 79 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2635 EP 2651 DI 10.1086/117477 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800026 ER PT J AU BRANDT, JC HEAP, SR BEAVER, EA BOGGESS, A CARPENTER, KG EBBETS, DC HUTCHINGS, JB JURA, M LECKRONE, DS LINSKY, JL MARAN, SP SAVAGE, BD SMITH, AM TRAFTON, LM WALTER, FM WEYMANN, R SNOW, M RANDALL, CE AKE, TB ROBINSON, RD WAHLGREN, G AF BRANDT, JC HEAP, SR BEAVER, EA BOGGESS, A CARPENTER, KG EBBETS, DC HUTCHINGS, JB JURA, M LECKRONE, DS LINSKY, JL MARAN, SP SAVAGE, BD SMITH, AM TRAFTON, LM WALTER, FM WEYMANN, R SNOW, M RANDALL, CE AKE, TB ROBINSON, RD WAHLGREN, G TI AN ATLAS OF ALPHA-ORIONIS OBTAINED WITH THE GODDARD HIGH-RESOLUTION SPECTROGRAPH ON THE HUBBLE-SPACE-TELESCOPE SO ASTRONOMICAL JOURNAL LA English DT Article ID II EMISSION-LINES; FE-II; COOL STARS; EXCITATION; SPECTRA C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI C-011,LA JOLLA,CA 92093. BALL AEROSP SYST GRP,BOULDER,CO 80306. DOMINION ASTROPHYS OBSERV,VICTORIA,BC V8X 4M6,CANADA. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. UNIV COLORADO,JOINT INST LAB ASTROPHYS,BOULDER,CO. NATL INST STAND & TECHNOL,BOULDER,CO 80309. UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706. MCDONALD OBSERV,AUSTIN,TX. UNIV TEXAS,DEPT ASTRON,AUSTIN,TX 78712. SUNY STONY BROOK,STONY BROOK,NY 11794. CARNEGIE INST WASHINGTON OBSERV,PASADENA,CA 91101. NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,ASTRON PROGRAM,GREENBELT,MD 20771. RP BRANDT, JC (reprint author), UNIV COLORADO,ATMOSPHER & SPACE PHYS LAB,CAMPUS BOX 392,BOULDER,CO 80309, USA. RI heap, sara/E-2237-2012; Carpenter, Kenneth/D-4740-2012; Randall, Cora/L-8760-2014 OI Randall, Cora/0000-0002-4313-4397 NR 41 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JUN PY 1995 VL 109 IS 6 BP 2706 EP 2735 DI 10.1086/117484 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA978 UT WOS:A1995RA97800033 ER PT J AU GIAMPIERI, G AF GIAMPIERI, G TI SINUSOIDAL GRAVITATIONAL-WAVES FROM MASS-VARYING BINARY-SYSTEMS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE GALAXIES, NUCLEI; ACTIVE; GRAVITATION; BLACK HOLE PHYSICS ID ACTIVE GALACTIC NUCLEI; BLACK-HOLES; EVOLUTION; ACCRETION; QUASARS; RADIATION; GALAXIES; OBJECTS AB It is believed that most quasars and galaxies present two common features: the presence in their core of a supermassive object, and the experience of one or more encounters with other galaxies. In this scenario, it is likely that a substantial fraction of active galactic nuclei harbour a supermassive binary, fueled by an accretion disk. These binaries would certainly be among the strongest sources of sinusoidal gravitational waves. We investigate their evolution considering, simultaneously, the accretion of the black hole's masses from the disk, and the gravitational waves emitted during the orbital motion. We also consider other astrophysical scenarios involving a coalescing binary with non constant masses. RP GIAMPIERI, G (reprint author), CALTECH, JET PROP LAB, MS 301-150, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 33 TC 1 Z9 1 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 2 BP 331 EP 337 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RE752 UT WOS:A1995RE75200004 ER PT J AU HERBSTMEIER, U MEBOLD, U SNOWDEN, SL HARTMANN, D BURTON, WB MORITZ, P KALBERLA, PMW EGGER, P AF HERBSTMEIER, U MEBOLD, U SNOWDEN, SL HARTMANN, D BURTON, WB MORITZ, P KALBERLA, PMW EGGER, P TI THE SOFT-X-RAY BACKGROUND TOWARDS THE HIGH-VELOCITY-CLOUD COMPLEX-M - HI CLOUDS ASSOCIATED WITH THE HOT GALACTIC CORONA SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM, CLOUDS; ISM, INDIVIDUAL OBJECTS, HVC COMPLEX M; GALAXY, HALO; GALAXY, STRUCTURE; RADIO LINES, ATOMIC; X-RAYS, INTERSTELLAR ID WAY HALO GAS; ROSAT PSPC; DIFFUSE; ULTRAVIOLET; IONIZATION; DRACO; ABSORPTION; DISTANCES; FILAMENT; CIRRUS AB Observations with ROSAT have established that the emission of a diffuse hot plasma in the galactic halo contributes to the X-ray background at 1/4 keV. This paper addresses the question of the extent of this hot galactic corona and discusses the origin of the soft X-rays emitted there. Based on the Wisconsin soft X-ray surveys, Hirth et al. suggested that the interaction of HI high-velocity clouds with the galactic disk gas is at least partly responsible for the soft X-ray background. Here we compare the ROSAT 1/4 keV survey data towards the high-velocity-cloud Complex M with the new Leiden/Dwingeloo survey of galactic HI. The distance of this cloud complex with respect to the galactic plane has recently been constrained to lie between 1.5 and 4.4 kpc. To account for the observed distribution of soft X-ray emission, we consider the absorption of the X-ray photons by the neutral foreground gas including intermediate-and high-velocity neutral clouds. We find that the high-velocity clouds attenuate the soft X-ray background. This shows that the galactic corona extends at least up to several kiloparsecs from the galactic plane. Furthermore, we find evidence for a soft Xray edge-brightening of parts of the high-velocity clouds, suggesting that these clouds are contributing to the heating of the galactic corona. The heating mechanism itself remains unclear. C1 UNIV BONN, INST RADIOASTRON, D-53121 BONN, GERMANY. MAX PLANCK INST EXTRATERR PHYS, D-85740 GARCHING, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV SPACE RES ASSOC, 2300 RA LEIDEN, NETHERLANDS. STERREWACHT LEIDEN, 2300 RA LEIDEN, NETHERLANDS. RI Snowden, Steven/D-5292-2012 NR 73 TC 36 Z9 36 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 2 BP 606 EP 623 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RE752 UT WOS:A1995RE75200031 ER PT J AU HIVON, E BOUCHET, FR COLOMBI, S JUSZKIEWICZ, R AF HIVON, E BOUCHET, FR COLOMBI, S JUSZKIEWICZ, R TI REDSHIFT DISTORTIONS OF CLUSTERING - A LAGRANGIAN APPROACH SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE COSMOLOGY; GALAXIES, FORMATION; GALAXIES, STATISTICS; GALAXIES, THEORY; GALAXIES, LARGE SCALE GALAXIES, STRUCTURE OF UNIVERSE; GALAXIES, REDSHIFTS; METHODS, ANALYTICAL ID GRAVITATIONAL-INSTABILITY; PERTURBATION-THEORY; IRAS GALAXIES; UNIVERSE; SIMULATIONS; DENSITY; SAMPLE; FLUCTUATIONS; STATISTICS; SKEWNESS AB We study the effects of peculiar velocities on statistical measures of galaxy clustering. These effects occur when distances to the galaxies are estimated from their redshifts. It is assumed that the clustering pattern results from the gravitational instability of initially Gaussian, small-amplitude perturbations of a Friedman-Lemaitre cosmological model. Explicit expressions are given for an arbitrary density parameter Omega of the model, both when the cosmological constant, Lambda, is zero, and when the model is spatially flat, Omega + Lambda/3H(2) = 1. Kaiser (1987) had analyzed the redshift distortion of the two-point correlation function. This function determines the variance of the density field distribution function and can be computed using linear perturbation theory. We show here how to compute higher order moments in redshift space, paying special attention to the skewness, or third moment of the density field, and its Fourier space counterpart, the bispectrum. This calls for a weakly non-linear analysis. We rely on a perturbative expansion of particle trajectories in Lagrangian coordinates, using the formalism introduced by Moutarde et al. (1991) and further developed by Bouchet et al. (1992, 1994). This formalism extends to higher orders the Zel'dovich first order (i.e, linear) solution (1970). The lowest non-vanishing contribution to the skewness comes from the first and second-order terms in perturbation theory. Therefore, using Zel'dovich approximation would not be self-consistent and would yield inaccurate results. We show that a physically consistent and quantitatively accurate analysis of the growth skewness in redshift space can be obtained from second-order Lagrangian theory. With practical applications to redshift surveys in mind, we also study the effects of spatial smoothing of the evolved density field. The necessary formalism was developed by Juszkiewicz and Bouchet (1991) and Juszkiewicz et al. (1993a). Here we give the first complete account of these calculations; we also extend the formalism by explicitly taking redshift distortions into account. We give analytic expressions for the gravitationally induced skewness as a function of the power spectrum and of Omega, for a spherical top-hat and a Gaussian smoothing filter. We compare our analytical predictions with measurements performed in numerical simulations, and find good agreement. These results should then prove useful in analyzing large scale redshift surveys. In particular, our results, in conjunction with the recent suggestion of Fry (1994), may solve a well known problem which always arises in conventional dynamical determinations of the mean density of the universe. Such studies produce estimates of Omega which are coupled with the parameters describing the bias in the galaxy distribution. As a result, a biased Omega = 1 model is dynamically indistinguishable from an open, unbiased, one. For the first time, it may become possible to break this degeneracy, and decouple the estimates of linear and non-linear bias from the estimates of Omega and Lambda. C1 FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60510 USA. COPERNICUS CTR, PL-00716 WARSAW, POLAND. INST ADV STUDY, PRINCETON, NJ 08540 USA. RP HIVON, E (reprint author), INST ASTROPHYS, CNRS, 98 BIS BLVD ARAGO, F-75014 PARIS, FRANCE. RI Bouchet, Francois/B-5202-2014 NR 53 TC 98 Z9 100 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 3 BP 643 EP 660 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG130 UT WOS:A1995RG13000005 ER PT J AU DEMARTINO, D MOUCHET, M BONNETBIDAUD, JM VIO, R ROSEN, SR MUKAI, K AUGUSTEIJN, T GARLICK, MA AF DEMARTINO, D MOUCHET, M BONNETBIDAUD, JM VIO, R ROSEN, SR MUKAI, K AUGUSTEIJN, T GARLICK, MA TI A PHOTOMETRIC AND SPECTROSCOPIC STUDY OF BG CANIS-MINORIS SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE STARS, CATACLYSMIC VARIABLES; STARS, INDIVIDUAL (BGCMI (3A0729+103)); X-RAYS, BINARIES ID X-RAY OBSERVATIONS; INTERMEDIATE POLARS; WHITE-DWARF; SPIN-UP; EMISSION; DISCOVERY; EXOSAT AB The photometric and spectroscopic analysis presented here has revealed new observational features in the Intermediate Polar BG CMi. We have found a strong variability of the dominant light pulsations, rotational (913 s) and orbital (3.23 hr), on a timescale of years. Variations in the amplitude of the spin pulsation with epoch generally appear to be anti-correlated with that of the orbital modulation with the former decreasing while the latter increases. We do not find stable periodic signals at other frequencies as well as no indication of periodicity at the 847 s X-ray period. UV and optical orbital continuum modulations reveal two components at different temperatures. The hot contribution is identified with the bulge (the heated face of the hot-spot) and the cool one with the hot-spot itself eclipsed by the secondary star. Orbital phase resolved spectroscopy reveals a rotational disturbance in the HeII emission line, indicating a partial eclipse of circulating material around the white dwarf, possibly in the form of a ring. From the orbital motion of the white dwarf, we also infer that BG CMi is a moderate inclination system (i similar to 55 degrees - 75 degrees). C1 OBSERV PARIS, DAEC, SECT MEUDON, F-92195 MEUDON, FRANCE. UNIV DENIS DIDEROT, F-75005 PARIS, FRANCE. CENS, DAPNIA SAP, SERV ASTROPHYS, F-91191 GIF SUR YVETTE, FRANCE. UNIV LEICESTER, DEPT PHYS & ASTRON, LEICESTER LE1 7RH, LEICS, ENGLAND. NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. UNIV AMSTERDAM, ASTRON INST ANTON PANNEKOEK, 1098 SJ AMSTERDAM, NETHERLANDS. CTR HIGH ENERGY ASTROPHYS, 1098 SJ AMSTERDAM, NETHERLANDS. UNIV SUSSEX, SCH MATH & PHYS SCI, CTR ASTRON, BRIGHTON BN1 9QH, E SUSSEX, ENGLAND. RP DEMARTINO, D (reprint author), ESTEC, DEPT SPACE SCI, DIV ASTROPHYS, ESA IUE OBSERV, POB 50727, E-28080 MADRID, SPAIN. NR 28 TC 16 Z9 16 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 3 BP 849 EP 862 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG130 UT WOS:A1995RG13000022 ER PT J AU VANTHOR, WF DGANI, R VANDENHORN, LJ JANKA, HT AF VANTHOR, WF DGANI, R VANDENHORN, LJ JANKA, HT TI FLUX-LIMITED NEUTRINO DIFFUSION FOR MOVING-MEDIA SO ASTRONOMY & ASTROPHYSICS LA English DT Note DE ELEMENTARY PARTICLES; HYDRODYNAMICS; SUPERNOVAE, GENERAL METHODS, ANALYTICAL ID ARTIFICIAL OPACITY; RADIATIVE-TRANSFER; CLOSURE AB We formulate a spectral flux-limited neutrino transport scheme for hydrodynamical media such as type-II supernovae. It is special-relativistic to O(v/c), retains all Doppler terms, and is momentum conserving through the inclusion of static and dynamic artificial opacity. Our numerical transport calculations on a stellar background model illustrate how the material velocity held affects the neutrino flux and energy transfer to the matter. In particular, the transport scheme yields higher neutrino energy deposition in matter moving inward. The Doppler terms are found to be the main contribution to the dynamic artificial opacity and to lead to significant spectral shifts. C1 UNIV AMSTERDAM, INST THEORET PHYS, 1018 XE AMSTERDAM, NETHERLANDS. CALTECH, JET PROP LAB, CTR INFRARED PROC & ANAL, PASADENA, CA 91125 USA. MAX PLANCK INST ASTROPHYS, W-8046 GARCHING, GERMANY. NR 15 TC 1 Z9 1 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 3 BP 863 EP 868 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RG130 UT WOS:A1995RG13000023 ER PT J AU DEMARTINO, D BUCKELY, DAH MOUCHET, M MUKAI, K AF DEMARTINO, D BUCKELY, DAH MOUCHET, M MUKAI, K TI UV OBSERVATIONS OF THE POLAR SYSTEM RE-1938-461 SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE CATACLYSMIC VARIABLES; STARS, INDIVIDUAL(RE1938-461); ULTRAVIOLET, STARS ID PERIOD AB We present IUE orbital phase resolved observations of the polar system RE1938-461. We detect a strong variability of the prominent emission lines, C IV (1550 Angstrom), He II (1640 Angstrom) and N V (1240 Angstrom) at the orbital period of 140 min. Line velocity shifts are also detected with amplitudes and phasing consistent with those of the optical lines. We suggest that the bulk of the line emission arises from the magnetically confined accretion stream towards the white dwarf. Emission line flux can account for N 3% Of the soft X-ray black-body emitted at the white dwarf surface. UV continuum energy distribution indicates different components. While the far-UV can be accounted by a white dwarf at 20000 K, the near-UV presents increasing flux possibly due to Balmer continuum and cyclotron emission. Continuum flux appears to vary weakly along the orbital cycle. Indications that the far-UV flux increases and steepens at superior conjunction of the white dwarf suggest a contribution of the heated polar region. C1 UNIV CAPE TOWN, DEPT ASTRON, RONDEBOSCH 7700, SOUTH AFRICA. S AFRICAN ASTRON OBSERV, CAPE TOWN 7935, SOUTH AFRICA. OBSERV PARIS, DAEC, SECT MEUDON, F-92195 MEUDON, FRANCE. UNIV DENIS DIDEROT, F-75005 PARIS, FRANCE. NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. ESTEC, DEPT SPACE SCI, DIV ASTROPHYS, NOORDWIJK, NETHERLANDS. RP DEMARTINO, D (reprint author), IUE OBSERV, ESA, POB 50727, E-28080 MADRID, SPAIN. NR 20 TC 3 Z9 3 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUN PY 1995 VL 298 IS 1 BP L5 EP L8 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RD584 UT WOS:A1995RD58400002 ER PT J AU MCNAMARA, BJ HARMON, BA HARRISON, TE AF MCNAMARA, BJ HARMON, BA HARRISON, TE TI THE EXTRACTION OF DISCRETE FLUX MEASUREMENTS AND CONTINUOUS LIGHT CURVES FROM THE CGRO/BATSE SPECTROSCOPY DETECTOR DATASETS SO ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES LA English DT Article DE METHODS, DATA ANALYSIS; X-RAYS, STARS; STARS, SCO X-1 ID MULTIWAVELENGTH CAMPAIGN; SCORPIUS X-1 AB We present four techniques for the reduction of the continuously available BATSE Spectroscopy Detector (SD) discriminator data. These techniques apply to single flux measurements as the source rises and sets with respect to the Earth's limb as seen by a SD and to the extraction of entire source light curves while the source is visible from a SD. The influence of multiple sources on the extraction of these data is discussed. BATSE SD data for Sco X-1 are used to illustrate these extraction techniques. Examples of correlative optical. and BATSE SD data for Sco X-1 are presented, and future plans for the use of these data are discussed. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP MCNAMARA, BJ (reprint author), NEW MEXICO STATE UNIV,DEPT 4500,BOX 30001,LAS CRUCES,NM 88003, USA. NR 16 TC 8 Z9 8 U1 0 U2 0 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0365-0138 J9 ASTRON ASTROPHYS SUP JI Astron. Astrophys. Suppl. Ser. PD JUN PY 1995 VL 111 IS 3 BP 587 EP 599 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RF066 UT WOS:A1995RF06600013 ER PT J AU MARSH, KA HELOU, G AF MARSH, KA HELOU, G TI THE SPATIAL VARIATION OF THE INFRARED-TO-RADIO RATIO IN SPIRAL GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, PHOTOMETRY; GALAXIES, SPIRAL; INFRARED, GALAXIES; RADIO CONTINUUM, GALAXIES ID IRAS OBSERVATIONS; CONTINUUM; EMISSION AB We have produced two-dimensional maps of the intensity ratio, Q(60), of 60 mu m infrared to 20 cm radio continuum emission, for a set of 25 nearby galaxies, mostly spirals. The ratio maps were obtained from infrared images made using IRAS data with the maximum correlation method, and radio images made using VLA data. Before taking the ratio, the radio images were processed so as to have the same resolution properties as the infrared images; the final spatial resolution in all cases is approximately 1', corresponding to 1-2 kpc for most galaxies. This resolution represents a significant improvement over previous studies. Our new high-resolution maps confirm the slow decrease of Q(60) with increasing radial distance from the nucleus, but show additional structure which is probably associated with separate sites of active star formation in the spiral arms. The maps show Q(60) to be more closely related to infrared surface brightness than to the radial distance r in the galaxy disk. We note also that the Q(60) gradients are absent (or at least reduced) for the edge-on galaxies, a property which can be attributed to the dilution of contrast due to the averaging of the additional structure along the line of sight. The results are all in qualitative agreement with the suggestion that the radio image represents a smeared version of the infrared image, as would be expected on the basis of current models in which the infrared-radio correlation is driven by the formation of massive stars, and the intensity distribution of radio emission is smeared as a result of the propagation of energetic electrons accelerated during the supernova phase. C1 CALTECH,CTR INFRARED PROC & ANAL,PASADENA,CA 91125. RP MARSH, KA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 306-451,PASADENA,CA 91109, USA. NR 18 TC 30 Z9 30 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP 599 EP 606 DI 10.1086/175724 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500008 ER PT J AU TURNER, TJ GEORGE, IM MADEJSKI, GM KITAMOTO, S SUZUKI, T AF TURNER, TJ GEORGE, IM MADEJSKI, GM KITAMOTO, S SUZUKI, T TI ASCA AND ROSAT OBSERVATIONS OF NRAO-140 AND IX-PERSEI SO ASTROPHYSICAL JOURNAL LA English DT Article DE QUASARS, INDIVIDUAL (NRAO 140); RADIATION MECHANISMS, NONTHERMAL; STARS, INDIVIDUAL (IX PERSEI); X-RAYS, GALAXIES; X-RAYS, STARS ID X-RAY-SPECTRA; ACTIVE GALACTIC NUCLEI; EXTRAGALACTIC RADIO-SOURCES; RS-CANUM-VENATICORUM; SEYFERT-GALAXIES; BINARY-SYSTEMS; COLD MATTER; ABSORPTION; EMISSION; QUASARS AB We report the results from observations of NRAO 140 carried out in the X-ray band using ROSAT and ASCA in 1992 and 1994. We find the source to be absorbed by an effective hydrogen column density of similar to 3 x 10(21) atoms cm(-2) during both epochs, consistent with the combined atomic and molecular column inferred from radio measurements along this line of sight through the Perseus cloud complex. We compare these results with previous X-ray absorption measurements and briefly comment upon the origin of the excess absorption which has been seen toward this source. We find the ASCA spectrum of NRAO 140 is well described by a power law of energy index alpha = 0.73 +/- 0.03 and also yields the tightest constraint to date on Fe K-shell emission, with 90% confidence upper limits of 38 and 31 eV for a narrow line at a rest frame energy of 6.4 and 6.7 keV respectively. This, along with a lack of hardening towards higher energies, suggests that either NRAO 140 is devoid of cold reprocessing material, the reprocessing material has a geometry in which the imprinted features are weak, and/or the X-ray emission is relativistically beamed towards us. We also report the detection of a serendipitous source in both the ASCA GIS and ROSAT fields of view. We identify this source as the binary star system IX Per and find its spectrum to be well fitted by a two-temperature Raymond-Smith plasma. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. OSAKA UNIV,FAC SCI,DEPT EARTH & SPACE SCI,TOYONAKA,OSAKA 560,JAPAN. RP TURNER, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 38 TC 18 Z9 18 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP 660 EP 665 DI 10.1086/175728 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500012 ER PT J AU DWEK, E ARENDT, RG HAUSER, MG KELSALL, T LISSE, CM MOSELEY, SH SILVERBERG, RF SODROSKI, TJ WEILAND, JL AF DWEK, E ARENDT, RG HAUSER, MG KELSALL, T LISSE, CM MOSELEY, SH SILVERBERG, RF SODROSKI, TJ WEILAND, JL TI MORPHOLOGY, NEAR-INFRARED LUMINOSITY, AND MASS OF THE GALACTIC BULGE FROM COBE DIRBE OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXY, STRUCTURE; INFRARED, STARS; GALAXY, STELLAR CONTENT ID STELLAR CONTENT; BAADES WINDOW; NUCLEAR BULGE; MILKY-WAY; M-GIANTS; GALAXY; MODEL; BARS; STARS; TELESCOPE AB Near-infrared images of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 mu m obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard the Cosmic Background Explorer (COBE) satellite are used to characterize its morphology and to determine its infrared luminosity and mass. Earlier analysis of the DIRBE observations (Weiland et al. 1994) provided supporting evidence for the claim made by Blitz and Spergel (1991) that the bulge is bar-shaped with its near end in the first Galactic quadrant. Adopting various triaxial analytical functions to represent the volume emissivity of the source, we confirm the barlike nature of the bulge and show that triaxial Gaussian-type functions provide a better fit to the data than other classes of functions, including an axisymmetric spheroid. The introduction of a ''boxy'' geometry, such as the one used by Kent, Dame, and Fazio (1991) improves the fit to the data. Our results show that the bar is rotated in the plane with its near side in the first Galactic quadrant creating an angle of 20 degrees + 10 degrees between its major axis and the line of sight to the Galactic center. Typical axis ratios of the bar are {1:0.33 +/- 0.11:0.23 +/- 0.08}, resembling the geometry of prolate spheroids. There is no statistically significant evidence for an out-of-plane tilt of the bar at 2.2 mu m, and marginal evidence for a tilt of approximate to 2 degrees at 4.9 mu m. The introduction of a roll around the intrinsic major axis of the bulge improves the ''boxy'' appearance of some functions. A simple integration of the observed projected intensity of the bulge gives a bulge luminosity of 1.2 x 10(9), 4.1 x 10(8), 2.3 x 10(8), and 4.3 x 10(7) L., respectively, at 1.25, 2.2, 3.5, and 4.9 mu m wavelength for a Galactocentric distance of 8.5 kpc. The 2.2 mu m luminosity function of the bulge population in the direction of Baade's window yields a bolometric luminosity of L(bol) = 5.3 x 10(9) L.. Stellar evolutionary models relate this luminosity to the number of main-sequence progenitor stars that currently populate the red giant branch. Combined with the recent determination of the main-sequence turnoff mass for the bulge by the Hubble Space Telescope (Hortzman et al. 1993) we derive a photometrically determined bulge mass of approximate to 1.3 x 10(10) M. for a Salpeter initial mass function extended down to 0.1 M.. C1 NASA, GODDARD SPACE FLIGHT CTR, APPL RES CORP, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, GEN SCI CORP, GREENBELT, MD 20771 USA. RP DWEK, E (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 685, GREENBELT, MD 20771 USA. RI Moseley, Harvey/D-5069-2012; Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 57 TC 408 Z9 410 U1 2 U2 5 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 JUN 1 PY 1995 VL 445 IS 2 BP 716 EP 730 DI 10.1086/175734 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500018 ER PT J AU SINGH, KP DRAKE, SA WHITE, NE AF SINGH, KP DRAKE, SA WHITE, NE TI A STUDY OF CORONAL X-RAY-EMISSION FROM SHORT-PERIOD ALGOL BINARIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, ECLIPSING; CIRCUMSTELLAR MATTER; STARS, CORONAE; X-RAYS, STARS ID CANUM-VENATICORUM SYSTEMS; ALL-SKY SURVEY; ECLIPSING BINARIES; TEMPERATURES; STARS; QUIESCENT; SOLAR; LIGHT AB A study of X-ray emission from five short-period Algol-type binaries based on observations with ASCA and ROSAT is presented. We have observed RZ Cas with both satellites, and beta Per, U Cep, delta Lib, and TW Dra with ROSAT. Significant intensity variations are seen in the X-ray emission from RZ Gas, U Cep, TW Dra, and delta Lib. These variations seem unrelated to the eclipsing behavior of these systems and are probably due to either rotational modulation of compact active regions on the surfaces of the chromospherically active secondary components or to flaring activity in the systems. The spectra of all but one of the systems require the presence of at least two discrete plasma components with different temperatures (0.6-0.7 keV, and similar to 2 keV) and the abundances of the medium-Z elements 20%-50% of the solar photospheric values. The high resolving power and signal-to-noise ratio of the ASCA spectra allow us to individually constrain the coronal abundances of O, Ne, Mg, Si, S, and Fe in RZ Gas. We demonstrate that, if we use the elemental abundances and temperatures obtained from the analysis of their ASCA spectra as (fixed) inputs, to fit the ROSAT PSPC spectra well requires the presence of a third component (kT similar to 0.2-0.3 keV) in RZ Cas and beta Per. A continuous emission measure model of the power-law type [EM(T) proportional to (T/T-max)(alpha)] generally gives a poor fit to the ASCA and ROSAT data on most sources. Circumstellar or circumbinary absorbing matter seems to be present in some of these systems, as indicated by the variable total column density needed to fit their X-ray spectra. RP SINGH, KP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 668,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 49 TC 45 Z9 45 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP 840 EP 854 DI 10.1086/175744 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500028 ER PT J AU BOYD, PT CARTER, PH GILMORE, R DOLAN, JF AF BOYD, PT CARTER, PH GILMORE, R DOLAN, JF TI NONPERIODIC VARIATIONS IN ASTROPHYSICAL SYSTEMS - INVESTIGATING FREQUENCY EVOLUTION SO ASTROPHYSICAL JOURNAL LA English DT Article DE CELESTIAL MECHANICS, STELLAR DYNAMICS; STARS, INDIVIDUAL (HD 60535); STARS, OSCILLATIONS; STARS, PECULIAR; METHODS, ANALYTICAL ID RAPIDLY OSCILLATING PECULIAR; SINGLE STAR SCATTERING; EQUAL MASSES; AP STARS; HD-60435; ENCOUNTERS AB We present a method related to the wavelet transform, the Gabor transform, for investigating astronomical time series containing nonconstant frequencies. Instances in which such data sets may arise include variable star light curves, numerical studies of the gravitational three-body problem, X-ray binaries, and signals from more exotic objects such as planets around pulsars and mass infall from accretion structures onto compact objects. As an illustration of its power, we apply the technique to a numerical data set of a gravitational three-body interaction and to photometry of the rapidly oscillating peculiar A star HD 60435. In the three-body example, the method provides an insightful shorthand that allows for the determination of episodes where the system behaves as two nearly Keplerian orbits. For HD 60435, the power in the main frequency exhibits unusual evolution over the duration of the observation. C1 USN, CTR SURFACE WARFARE, WHITE OAK, MD 20903 USA. DREXEL UNIV, DEPT PHYS & ATMOSPHER SCI, PHILADELPHIA, PA 19104 USA. NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. RP BOYD, PT (reprint author), UNIV SPACE RES ASSOC, WASHINGTON, DC 20036 USA. RI Boyd, Patricia/D-3274-2012 NR 34 TC 7 Z9 7 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 JUN 1 PY 1995 VL 445 IS 2 BP 861 EP 871 DI 10.1086/175746 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500030 ER PT J AU WOO, JW CLARK, GW BLONDIN, JM KALLMAN, TR NAGASE, F AF WOO, JW CLARK, GW BLONDIN, JM KALLMAN, TR NAGASE, F TI WIND DYNAMICS IN SMC X-1 .2. GINGA AND ROSAT OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, INDIVIDUAL (SMC X-1); STARS, MASS LOSS; X-RAYS, STARS ID CENTAURUS X-3; RAY; BEHAVIOR AB The X-ray phenomena of the binary system SMC X-1/Sk 160, observed with the Ginga and ROSAT X-ray observatories, are compared with computed phenomena derived from a three-dimensional hydrodynamical model of the stellar wind perturbed by X-ray heating and ionization which is described in the accompanying paper (Blondin & Woo 1995). In the model the B0 I primary star has a line-driven stellar wind in the region of the X-ray shadow and a thermal wind in the region heated by X-rays. We find general agreement between the observed and predicted X-ray spectrum throughout the binary orbit cycle, including the extended, variable, and asymmetric eclipse transitions and the period of deep eclipse. C1 N CAROLINA STATE UNIV,DEPT PHYS,RALEIGH,NC 27695. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. RP WOO, JW (reprint author), MIT,CTR SPACE RES,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. NR 30 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP 896 EP 908 DI 10.1086/175749 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500033 ER PT J AU GARY, GA DEMOULIN, P AF GARY, GA DEMOULIN, P TI REDUCTION, ANALYSIS, AND PROPERTIES OF ELECTRIC-CURRENT SYSTEMS IN SOLAR ACTIVE REGIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, ACTIVITY; SUN, CHROMOSPHERE; SUN, CORONA; SUN, MAGNETIC FIELDS ID PHOTOSPHERIC MAGNETIC-FIELD; SPACE-FLIGHT-CENTER; VECTOR MAGNETOGRAMS; 180-DEGREES AMBIGUITY; FLARE PHENOMENA; REMOVAL; SIGN; EXTRAPOLATION; RECONNECTION; MORPHOLOGY AB The specific attraction and, in large part, the significance of solar vector magnetograms lie in the fact that they give the most important data on the electric currents and the nonpotentiality of active regions. Using the vector magnetograms from the Marshall Space Flight Center (MSFC), we employ a unique technique in the area of data analysis for resolving the 180 degrees ambiguity in order to calculate the spatial structure of the vertical electric current density. The 180 degrees ambiguity is resolved by applying concepts from the nonlinear multivariable optimization theory. The technique is shown to be of particular importance in very nonpotential active regions. The characterization of the vertical electric current density for a set of vector magnetograms using this method then gives the spatial scare, locations, and magnitude of these current systems. The method, which employs an intermediate parametric function which covers the magnetogram and which defines the local ''preferred'' direction, minimizes a specific functional of the observed transverse magnetic field. The specific functional that is successful is the integral of the square of the vertical current density. We find that the vertical electric current densities have common characteristics for the extended bipolar beta gamma delta-regions studied. The largest current systems have j(z)'s which maximizes around 30 mA m(-2) and have a linear decreasing distribution to a diameter of 30 Mm. C1 OBSERV PARIS,MEUDON SECT,DASOP,CNRS,URA 326,F-92195 MEUDON,FRANCE. RP GARY, GA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,ES82,HUNTSVILLE,AL 35812, USA. OI Demoulin, Pascal/0000-0001-8215-6532 NR 72 TC 37 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 JUN 1 PY 1995 VL 445 IS 2 BP 982 EP 998 DI 10.1086/175757 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA625 UT WOS:A1995RA62500041 ER PT J AU CORCORAN, MF RAWLEY, GL SWANK, JH PETRE, R AF CORCORAN, MF RAWLEY, GL SWANK, JH PETRE, R TI FIRST DETECTION OF X-RAY VARIABILITY OF ETA-CARINAE SO ASTROPHYSICAL JOURNAL LA English DT Article DE CIRCUMSTELLAR MATTER; STARS, ACTIVITY; STARS, INDIVIDUAL (ETA CARINAE); STARS, PECULIAR; X-RAYS, STARS ID NEBULA; EMISSION AB Recent ROSAT Position Sensitive Proportional Counter observations for the first time unequivocally reveal the presence of a compact source of hard X-ray emission centered on the peculiar star eta Car. These observations also show a dramatic change in the hard-band (E > 1.6 keV) counting rate by about a factor of 2 in a 4 month interval. Thus, strong variability, which is a characteristic of eta Car in radio through IR and visible-band wavelengths, is also observed at X-ray energies. The increase in hard X-ray emission could be the result of a tripling of the mass-loss rate in less than 4 months. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. APPL RES CORP,WASHINGTON,DC. RP CORCORAN, MF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI Swank, Jean/F-2693-2012 NR 20 TC 43 Z9 43 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP L121 EP L124 DI 10.1086/187904 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA626 UT WOS:A1995RA62600013 ER PT J AU WHITE, NE GIOMMI, P HEISE, J ANGELINI, L FANTASIA, S AF WHITE, NE GIOMMI, P HEISE, J ANGELINI, L FANTASIA, S TI RX J0045.4+4154 - A RECURRENT SUPERSOFT X-RAY TRANSIENT IN M31 SO ASTROPHYSICAL JOURNAL LA English DT Article DE NOVAE; STARS, INDIVIDUAL (RX J0045.4+4154); X-RAYS, STARS ID LARGE MAGELLANIC CLOUD; ROSAT; MODELS; CAL-83 AB Using data extracted from the ROSAT archive we have discovered a recurrent supersoft X-ray transient RX J0045.4+4154 in M31. The first outburst began on 1992 February 2 and continued for at least 4 days, until the end of the observation sequence. A second outburst that lasted more than 6 days was seen to begin on 1993 January 7. The X-ray spectrum on both occasions yields a characteristic blackbody temperature of similar to 90 eV. For a range of plausible continuum models, the hydrogen column density is (0.8-1.5) x 10(21) cm(-2) and is consistent with the source being located in M31. This implies an unabsorbed 0.1-2.0 keV peak luminosity of similar to 10(38) ergs s(-1). This is the first recurrent X-ray transient to be found in M31 and is particularly notable because it is much softer than the bright X-ray transients seen in our Galaxy. The spectrum is characteristic of the supersoft class of X-ray sources, which are thought to be accreting white dwarfs that have a hydrogen-burning surface layer. A fit to a white dwarf model atmosphere gives a temperature of 10(6) K, the hottest found so far. This high temperature is consistent with a white dwarf mass of 1.3-1.4 M., approaching the Chandrasekhar limit, and burning dose to the nuclear stability limit. C1 ESRIN,EUROPEAN SPACE AGCY,DIV INFORMAT SYST,EUROPEAN SPACE INFORMAT SYST,I-00044 FRASCATI,ITALY. SRON SPACE RES UTRECHT,ASTROPHYS WORKING GRP,3584 CA UTRECHT,NETHERLANDS. RP WHITE, NE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 31 TC 17 Z9 17 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUN 1 PY 1995 VL 445 IS 2 BP L125 EP L128 DI 10.1086/187905 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA626 UT WOS:A1995RA62600014 ER PT J AU BICAY, MD KOJOIAN, G SEAL, J DICKINSON, DF MALKAN, MA AF BICAY, MD KOJOIAN, G SEAL, J DICKINSON, DF MALKAN, MA TI A MULTIFREQUENCY RADIO-CONTINUUM AND IRAS FAINT SOURCE SURVEY OF MARKARIAN GALAXIES SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE GALAXIES, SEYFERT; GALAXIES, STARBURST; INFRARED, GALAXIES; RADIO CONTINUUM, GALAXIES SURVEYS ID EMISSION-LINE OBJECTS; INFRARED-EMISSION; MULTIPLE NUCLEI; POSITIONS AB Results are presented from a multifrequency radio continuum survey of Markarian galaxies (MRKs) and are supplemented by IRAS infrared data from the Faint Source Survey. Radio data are presented for 899 MRKs observed at nu = 4.755 GHz with the NRAO-Green Bank 300 foot(91 m) telescope, including nearly 88% of those objects in Markarian lists VI-XIV. In addition, 1.415 GHz measurements of 258 MRKs, over 30% of the MRKs accessible from NAIC-Arecibo, are reported. Radio continuum observations of smaller numbers of MRKs were made at 10.63 GHz and at 23.1 GHz and are also presented. The ( 1.415 GHz, 4.755 GHz) percentages of ''probable'' detections were found to be (37%, 15%) for the MRK sample as a whole. These detection rates increased to (49%, 33%) among Seyfert MRKs, and to (73%, 42%) for those classified as having starburst nuclei. The vast majority of radio-detected MRKs have radio luminosities h(2)P(1.415) < 10(23) W HZ(-1) characteristic of ''normal galaxies.'' Infrared data from the IRAS Faint Source Survey (Ver. 2) are presented for 944 MRKs, with reasonably secure identifications extracted from the NASA/IPAC Extragalactic Database. MRKs exhibit the same canonical infrared characteristics as those reported for various other galaxy samples, that is, the well-known enhancement of the 25 mu m/60 mu m color ratio among Seyfert MRKs, and a clear tendency for MRKs with warmer 60 mu m/100 mu m colors to also possess cooler 12 mu m/25 mu m colors. In addition, non-Seyfert MRKs are found to obey the well-documented infrared/radio luminosity correlation, with the tightest correlation seen for starburst MRKs. Linear regression fits to the infrared/radio correlations yield these relationships: log L(FIR) = 0.77 log P-1.415 + 19.95 (r = 0.96) and log L(FIR) = 0.89 log P-4.755 + 17.51 (r = 0.90). Mean values of the infrared/radio ratios are consistent with those derived for various optically selected galaxy samples. The FIR/radio ratios for starburst MRKs are enhanced by a factor of 3 over those for Seyfert MRKs. There is no statistically significant difference between the infrared/radio ratios of single-nucleus and multiple-nucleus MRKs, although the analysis is complicated by small sample sizes. C1 CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91125. NASA HEADQUARTERS,DIV ASTROPHYS,WASHINGTON,DC 20546. UNIV WISCONSIN,DEPT PHYS & ASTRON,EAU CLAIRE,WI 54702. CAMBRIDGE RES,CHAMPAIGN,IL 61821. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. UNIV CALIF LOS ANGELES,DEPT ASTRON,LOS ANGELES,CA 90024. RP BICAY, MD (reprint author), SMITHSONIAN INST,NATL AIR & SPACE MUSEUM,ASTROPHYS LAB,WASHINGTON,DC 20546, USA. NR 55 TC 34 Z9 34 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1995 VL 98 IS 2 BP 369 EP 440 DI 10.1086/192168 PG 72 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QZ758 UT WOS:A1995QZ75800001 ER PT J AU HILL, JK ISENSEE, JE BOHLIN, RC CHENG, KP HINTZEN, PMN OCONNELL, RW AF HILL, JK ISENSEE, JE BOHLIN, RC CHENG, KP HINTZEN, PMN OCONNELL, RW TI ULTRAVIOLET AND OPTICAL OBSERVATIONS OF OB ASSOCIATIONS IN M31 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE GALAXIES, INDIVIDUAL (M3L); GALAXIES, PHOTOMETRY; GALAXIES, STAR CLUSTERS ULTRAVIOLET; STARS ID IMAGING TELESCOPE; ROCKET ULTRAVIOLET; MASSIVE STARS; PHOTOMETRY; IDENTIFICATION; CLUSTERS AB Images of the central and southern parts of the local group Sb spiral galaxy M31 were obtained by the Ultraviolet Imaging Telescope during the Astro-l Spacelab mission. Stellar photometry is obtained for 611 stars in 59 van den Bergh associations in the near-UV A1 band (central wavelength 2490 Angstrom), and for 130 of these stars in the far-UV B1 band (central wavelength 1520 Angstrom). In addition, B-band magnitudes for 456 of the stars in similar to 30 associations, together with U- and R-band photometry for similar to 290 stars in similar to 15 associations are determined from CCD images. B-magnitudes from the catalog of Magnier et al. (1992) are given for 137 stars and R-magnitudes for 233 stars. Stellar positions are obtained from the ground-based CCD images and from UIT images. Total fluxes in the UV bands are measured for 63 associations. Finding charts are presented in the NUV and FUV bands, as well as one optical band. Tables give the images utilized in this investigation, the associations observed, with positions, total UV fluxes, extinctions estimated from color-magnitude diagrams, and stellar positions with photometry in up to five bands. UV color magnitude diagrams are presented with extinctions estimated by comparing the observed association color magnitude diagrams with colors and magnitudes of early-type stars computed from the IUE spectral atlas of Fanelli et al. (1992). Comparison with evolutionary models suggests a maximum initial mass similar to 85 M.. Ultraviolet extinction within most M31 OB associations is found to follow an extinction curve similar to that of Hutchings et al. (1992). The variation in the fraction of near-UV stars also measured in the far-UV among the associations is probably caused by variations in age, extinction, and the degree of foreground contamination. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. CALIF STATE UNIV FULLERTON,DEPT PHYS,FULLERTON,CA 92634. CALIF STATE UNIV LONG BEACH,DEPT PHYS & ASTRON,LONG BEACH,CA 90840. UNIV VIRGINIA,CHARLOTTESVILLE,VA 22903. NATL RADIO ASTRON OBSERV,CHARLOTTESVILLE,VA 22903. RP HILL, JK (reprint author), HUGHES STX,4400 FORBES BLVD,LANHAM,MD 20706, USA. NR 32 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUN PY 1995 VL 98 IS 2 BP 595 EP 615 DI 10.1086/192171 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QZ758 UT WOS:A1995QZ75800004 ER PT J AU BAKER, WE EMMITT, GD ROBERTSON, F ATLAS, RM MOLINARI, JE BOWDLE, DA PAEGLE, J HARDESTY, RM MENZIES, RT KRISHNAMURTI, TN BROWN, RA POST, MJ ANDERSON, JR LORENC, AC MCELROY, J AF BAKER, WE EMMITT, GD ROBERTSON, F ATLAS, RM MOLINARI, JE BOWDLE, DA PAEGLE, J HARDESTY, RM MENZIES, RT KRISHNAMURTI, TN BROWN, RA POST, MJ ANDERSON, JR LORENC, AC MCELROY, J TI LIDAR-MEASURED WINDS FROM SPACE - A KEY COMPONENT FOR WEATHER AND CLIMATE PREDICTION SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID ATMOSPHERIC AEROSOL BACKSCATTER; DATA ASSIMILATION SYSTEM; DOPPLER LIDAR; CO2-LASER WAVELENGTHS; PERFORMANCE EVALUATION; TROPOSPHERIC AEROSOL; AMAZON DEFORESTATION; CO2 LIDAR; AIRBORNE; SIMULATION AB The deployment of a space-based Doppler lidar would provide information that is fundamental to advancing the understanding and prediction of weather and climate. This paper reviews the concepts of wind measurement by Doppler lidar, highlights the results of some observing system simulation experiments with lidar winds, and discusses the important advances in earth system science anticipated with lidar winds. Observing system simulation experiments, conducted using two different general circulation models, have shown 1) that there is a significant improvement in the forecast accuracy over the Southern Hemisphere and tropical oceans resulting from the assimilation of simulated satellite wind data, and 2) that wind data are significantly more effective than temperature or moisture data in controlling analysis error. Because accurate wind observations are currently almost entirely unavailable for the vast majority of tropical cyclones worldwide, lidar winds have the potential to substantially improve tropical cyclone forecasts. Similarly, to improve water vapor flux divergence calculations, a direct measure of the ageostrophic wind is needed since the present level of uncertainty cannot be reduced with better temperature and moisture soundings alone. C1 SIMPSON WEATHER ASSOCIATES,CHARLOTTESVILLE,VA. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. SUNY ALBANY,ALBANY,NY 12222. UNIV ALABAMA,HUNTSVILLE,AL 35899. UNIV UTAH,SALT LAKE CITY,UT. NOAA,ENVIRONM TECHNOL LAB,BOULDER,CO. NASA,JET PROP LAB,PASADENA,CA. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV WASHINGTON,SEATTLE,WA 98195. UNIV WISCONSIN,CTR SPACE SCI & ENGN,MADISON,WI 53706. UNITED KINGDOM METEOROL OFF,BRACKNELL,BERKS,ENGLAND. US EPA,LAS VEGAS,NV 89193. RP BAKER, WE (reprint author), NATL CTR ENVIRONM PREDICT,5200 AUTH RD,CAMP SPRINGS,MD 20746, USA. RI Atlas, Robert/A-5963-2011; Hardesty, Robert/H-9844-2013 OI Atlas, Robert/0000-0002-0706-3560; NR 99 TC 111 Z9 126 U1 4 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1995 VL 76 IS 6 BP 869 EP 888 DI 10.1175/1520-0477(1995)076<0869:LMWFSA>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RG210 UT WOS:A1995RG21000002 ER PT J AU WHITLOCK, CH CHARLOCK, TP STAYLOR, WF PINKER, RT LASZLO, I OHMURA, A GILGEN, H KONZELMAN, T DIPASQUALE, RC MOATS, CD LECROY, SR RITCHEY, NA AF WHITLOCK, CH CHARLOCK, TP STAYLOR, WF PINKER, RT LASZLO, I OHMURA, A GILGEN, H KONZELMAN, T DIPASQUALE, RC MOATS, CD LECROY, SR RITCHEY, NA TI FIRST GLOBAL WCRP SHORTWAVE SURFACE RADIATION BUDGET DATASET SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CLOUD CLIMATOLOGY PROJECT; INCIDENT SOLAR-RADIATION; SATELLITE DATA; IRRADIANCE; CALIBRATION; VALIDATION; ISCCP; MODEL AB Shortwave radiative fluxes that reach the earth's surface are key factors that influence atmospheric and oceanic circulations as well as surface climate. Yet, information on these fluxes is meager. Surface site data are generally available from only a limited number of observing stations over land. Much less is known about the large-scale variability of the shortwave radiative fluxes over the oceans, which cover most of the globe. Recognizing the need to produce global-scale fields of such fluxes for use in climate research, the World Climate Research Program has initiated activities that led to the establishment of the Surface Radiation Budget Climatology Project with the ultimate goal to determine various components of the surface radiation budget from satellite data. in this paper, the first global products that resulted from this activity are described. Month ly and daily data on a 280-km grid scale are available. Samples of climate parameters obtainable from the dataset are presented. Emphasis is given to validation and limitations of the results. For most of the globe, satellite estimates have bias values between +/-20 W m(-2) and rms values are around 25 W m(-2). There are specific regions with much larger uncertainties however. C1 UNIV MARYLAND,DEPT METEOROL,COLLEGE PK,MD. ETH ZURICH,INST GEOG,ZURICH,SWITZERLAND. LOCKHEED ENGN & SCI CO,HAMPTON,VA. RP WHITLOCK, CH (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 420,HAMPTON,VA 23665, USA. RI Laszlo, Istvan/F-5603-2010; Pinker, Rachel/F-6565-2010 OI Laszlo, Istvan/0000-0002-5747-9708; NR 34 TC 115 Z9 120 U1 0 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1995 VL 76 IS 6 BP 905 EP 922 DI 10.1175/1520-0477(1995)076<0905:FGWSSR>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RG210 UT WOS:A1995RG21000004 ER PT J AU GUMLEY, LE KING, MD AF GUMLEY, LE KING, MD TI REMOTE-SENSING OF FLOODING IN THE US UPPER MIDWEST DURING THE SUMMER OF 1993 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The U.S. upper Midwest was subjected to severe flooding during the summer of 1993. Heavy rainfall in the Mississippi River basin from April through July caused flooding of many Midwest rivers, including the Mississippi, Illinois, Missouri, and Kansas Rivers. The flood crest of 15.1 m at St. Louis, Missouri, on 1 August 1993 was the highest ever measured, surpassing the previous record of 13.2 m set on 28 April 1973. Damage estimates include at least 47 flood-related deaths and a total damage cost of $12 billion. Remotely sensed imagery of severe flooding in the U.S. Midwest was obtained under cloud-free skies on 29 July 1993 by the MODIS (Moderate Resolution Imaging Spectroradiometer) Airborne Simulator (MAS). The MAS is a newly developed scanning spectrometer with 50 spectral bands in the wavelength range 0.55-14.3 mu m. By combining spectral bands centered at 2.14, 0.94, and 0.66 mu m in red, green, and blue display channels, respectively, false color images were created from the MAS data obtained on 29 July 1993 that dramatically illustrate the extent of flooding near St. Louis and near Kansas City, Missouri. Estimation of the total flooded area in the MAS scene acquired near St. Louis was accomplished by comparing the MAS scene to a Landsat-5 thematic mapper (TM) scene of the same area acquired on 14 April 1984 in nonflood conditions. For comparison, the MAS band centered at 0.94 mu m and the TM band centered at 1.65 mu m were selected because of the high contrast seen in these bands between land and water-covered surfaces. An estimate of the area covered by water in the MAS and TM scenes was obtained by developing land/water brightness thresholds from histograms of the MAS and TM digital image data. After applying the thresholds, the difference between the area covered by water in the MAS and TM scenes, and hence the flooded area in the MAS scene, was found to be about 396 km(2), or about 153 square miles. C1 APPL RES CORP,LANDOVER,MD 20785. NASA,GODDARD SPACE FLIGHT CTR,EARTH SCI DIRECTORATE,GREENBELT,MD 20771. RP GUMLEY, LE (reprint author), UNIV WISCONSIN,COOPERAT INST METEOROL SATELLITE STUDIES,MADISON,WI, USA. RI King, Michael/C-7153-2011 OI King, Michael/0000-0003-2645-7298 NR 22 TC 8 Z9 8 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JUN PY 1995 VL 76 IS 6 BP 933 EP 943 DI 10.1175/1520-0477(1995)076<0933:RSOFIT>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RG210 UT WOS:A1995RG21000006 ER PT J AU GILMARTIN, WG EBERHARDT, LL AF GILMARTIN, WG EBERHARDT, LL TI STATUS OF THE HAWAIIAN MONK SEAL (MONACHUS-SCHAUINSLANDI) POPULATION SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Note ID SURVIVAL RATES AB Restoration of the Hawaiian monk seal (Monachus schauinslandi) population to its former abundance poses a number of problems in managing a complex system. Sharp differences in history and current trend exist among the six major pupping sites. A severely unbalanced adult sex ratio has resulted in deaths from ''mobbing'' of estrus females at two sites. Some unknown factor apparently severely reduced the numbers of females at three of the sites and thus produced the observed excess of males. Sex ratios subsequently decreased, but losses of adult females continue at two sites. A simple model indicates that sex ratios at the two sites where mobbing is a problem would require more than 10 years to approach an equilibrium value. Data on trends from counts are compared with estimates from reproduction and survival rates and agree closely except at one site (Kure Atoll), where introductions of young females have been made. RP GILMARTIN, WG (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 18 TC 18 Z9 23 U1 5 U2 15 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 JUN PY 1995 VL 73 IS 6 BP 1185 EP 1190 DI 10.1139/z95-141 PG 6 WC Zoology SC Zoology GA RX214 UT WOS:A1995RX21400022 ER PT J AU LI, YW ELISHAKOFF, I STARNES, JH AF LI, YW ELISHAKOFF, I STARNES, JH TI BUCKLING MODE LOCALIZATION IN A MULTISPAN PERIODIC STRUCTURE WITH A DISORDER IN A SINGLE SPAN SO CHAOS SOLITONS & FRACTALS LA English DT Article AB This paper investigates the buckling mode localization in the periodic multi-span beam with disorder occurring in an arbitrary single span. The analytical finite difference calculus is used in conjunction with the conventional displacement method to derive the transcendental equations from which buckling load is calculated. The underlying treatment is general and the solution thus obtained is exact. Numerical results show that the buckling mode is highly localized in the vicinity of the disordered span of the beam. C1 FLORIDA ATLANTIC UNIV, DEPT MECH ENGN, BOCA RATON, FL 33431 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23664 USA. RP FLORIDA ATLANTIC UNIV, CTR APPL STOCHAST RES, BOCA RATON, FL 33431 USA. NR 22 TC 11 Z9 12 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 EI 1873-2887 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD JUN PY 1995 VL 5 IS 6 BP 955 EP 969 DI 10.1016/0960-0779(94)00211-8 PG 15 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA RD823 UT WOS:A1995RD82300005 ER PT J AU ADAMS, RM FLEMING, RA CHANG, CC MCCARL, BA ROSENZWEIG, C AF ADAMS, RM FLEMING, RA CHANG, CC MCCARL, BA ROSENZWEIG, C TI A REASSESSMENT OF THE ECONOMIC-EFFECTS OF GLOBAL CLIMATE-CHANGE ON US AGRICULTURE SO CLIMATIC CHANGE LA English DT Article AB This study uses recent GCM forecasts, improved plant science and water supply data and refined economic modeling capabilities to reassess the economic consequences of long-term climate change on U.S. agriculture. Changes in crop yields, crop water demand and irrigation water arising from climate change result in changes in economic welfare. Economic consequences of the three GCM scenarios are mixed; GISS and GFDL-QFlux result in aggregate economic gains, UKMO implies losses. As in previous studies, the yield enhancing effects of atmospheric CO2 are an important determinant of potential economic consequences. Inclusion of changes in world food production and associated export changes generally have a positive affect on U.S. agriculture. As with previous studies, the magnitude of economic effects estimated here are a small percentage of U. S. agricultural value. C1 TEXAS A&M UNIV,COLLEGE STN,TX 77843. COLUMBIA UNIV,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025. RP ADAMS, RM (reprint author), OREGON STATE UNIV,DEPT AGR & RESOURCE ECON,CORVALLIS,OR 97331, USA. RI McCarl, Bruce/E-9445-2011 NR 28 TC 87 Z9 88 U1 0 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD JUN PY 1995 VL 30 IS 2 BP 147 EP 167 DI 10.1007/BF01091839 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RF032 UT WOS:A1995RF03200002 ER PT J AU CHAN, WM BUNING, PG AF CHAN, WM BUNING, PG TI SURFACE GRID GENERATION METHODS FOR OVERSET GRIDS SO COMPUTERS & FLUIDS LA English DT Article AB Efficient methods for performing surface grid generation for overset (overlapping) grids are presented, These include a scheme using hyperbolic partial differential equations and an algebraic marching scheme. The combined use of hyperbolic and algebraic methods in easing the task of surface domain decomposition and surface grid generation for the Chimera overset grid approach is discussed. Extensions of a basic hyperbolic scheme are made to march over a collection of panel networks where each network consists of a rectangular array of panels (quadrilateral cells). Other enhancements include a more robust projection scheme and methods to improve grid boundary control. Examples are given for general applications in overset grid methods such as collar grids for intersecting geometric components and cap grids at fuselage noses and wing tips. More complex examples include surface grids For the Space Shuttle Orbiter and the V-22 tiltrotor. RP CHAN, WM (reprint author), NASA,AMES RES CTR,MCAT INST,MAIL STOP T27B-2,MOFFETT FIELD,CA 94035, USA. NR 24 TC 8 Z9 9 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUN PY 1995 VL 24 IS 5 BP 509 EP 522 DI 10.1016/0045-7930(95)00003-U PG 14 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA RH347 UT WOS:A1995RH34700001 ER PT J AU MAVRIPLIS, DJ VENKATAKRISHNAN, V AF MAVRIPLIS, DJ VENKATAKRISHNAN, V TI AGGLOMERATION MULTIGRID FOR 2-DIMENSIONAL VISCOUS FLOWS SO COMPUTERS & FLUIDS LA English DT Article ID EULER EQUATIONS; MESHES AB Agglomeration multigrid, which has been demonstrated as an efficient and automatic technique for the solution of the Euler equations on unstructured meshes, is extended to Viscous turbulent flows. For diffusion terms, coarse grid discretizations are not possible, and more accurate grid transfer operators are required as well. A Galerkin coarse grid operator construction and an implicit prolongation operator are proposed. Their suitability is evaluated by examining their effect on the solution of Laplace's equation. The resulting strategy is employed to solve the Reynolds-averaged Navier-Stokes equations for aerodynamic flows. Convergence rates comparable to those obtained by a previously developed non-nested mesh multigrid approach are demonstrated, and suggestions for further improvements are given. RP MAVRIPLIS, DJ (reprint author), NASA,LANGLEY RES CTR,ICASE,MAIL STOP 132C,HAMPTON,VA 23681, USA. NR 22 TC 42 Z9 42 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUN PY 1995 VL 24 IS 5 BP 553 EP 570 DI 10.1016/0045-7930(95)00005-W PG 18 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA RH347 UT WOS:A1995RH34700003 ER PT J AU EKLUND, DR FLETCHER, DG HARTFIELD, RJ NORTHAM, GB DANCEY, CL AF EKLUND, DR FLETCHER, DG HARTFIELD, RJ NORTHAM, GB DANCEY, CL TI A COMPARATIVE COMPUTATIONAL EXPERIMENTAL INVESTIGATION OF MACH-2 FLOW OVER A REARWARD-FACING STEP SO COMPUTERS & FLUIDS LA English DT Article ID INDUCED IODINE FLUORESCENCE; TEMPERATURE-MEASUREMENT; SUPERSONIC COMBUSTOR AB A numerical study of the Mach 2 flow over a rearward-facing step was performed using the SPARK Navier-Stokes code as a companion to a comprehensive experimental investigation conducted at the University of Virginia using Laser-Induced Iodine Fluorescence (LIIF) and Laser Doppler Anemometry (LDA) techniques. Turbulence was modeled with the Baldwin-Lomax turbulence model. First, calculations of the Mach 2 nozzle were performed and excellent agreement was obtained between the calculated and measured velocity profiles one step height upstream of the step. Secondly, comparisons were made between the calculations and measurements obtained with both planar and pointwise fluorescence techniques for the rearward-facing step Row field. This study represents the first comparison between in-stream static temperature measurements and CFD calculations for supersonic Row over a rearward-facing step. Agreement between the planar measurements and the calculations was observed regarding the position of the prominent flow features: the expansion fan, the shear layer, and the reattachment shock. Significantly lower temperature measurements were observed in low-momentum regions of the flow field. Comparisons between the pointwise measurements and the calculations exhibited very good quantitative agreement. The calculated and measured pressures, temperatures and velocities agreed within 5% at approx. 85% of the experimental locations. C1 NATL RES COUNCIL,HAMPTON,VA. UNIV VIRGINIA,CHARLOTTESVILLE,VA. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. NR 22 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUN PY 1995 VL 24 IS 5 BP 593 EP 608 DI 10.1016/0045-7930(95)00004-V PG 16 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA RH347 UT WOS:A1995RH34700005 ER PT J AU EIDSON, TM ERLEBACHER, G AF EIDSON, TM ERLEBACHER, G TI IMPLEMENTATION OF A FULLY BALANCED PERIODIC TRIDIAGONAL SOLVER ON A PARALLEL DISTRIBUTED-MEMORY ARCHITECTURE SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article AB While parallel computers offer significant computational performance, it is generally necessary to evaluate several programming strategies, Two programming strategies for a fairly common problem-a periodic tridiagonal solver-are developed and evaluated, Simple model calculations as web as timing results are presented to evaluate these strategies. The particular tridiagonal solver evaluated is used in many computational fluid dynamic simulation codes. The feature that makes this algorithm unique is that these simulation codes usually require simultaneous solution for multiple right-hand-sides (RHS) of the system of equations, Each RHS solutions is independent and thus can be computed in parallel, Thus, a Gaussian-elimination-type algorithm can be used in a parallel computation and more complicated approaches such as cyclic reduction are not required. The two strategies are a transpose strategy and a distributed solver strategy. For the transpose strategy, the data are moved so that a subset of all the RHS problems is solved on each of the several processors, This usually requires significant data movement between processor memories across a network, The second strategy attempts to have the algorithm follow the data across processor boundaries in a chained manner, This usually requires significantly less data movement. An approach to accomplish this second strategy in a near-perfect load-balanced manner is developed,In addition, an algorithm will be shown to directly transform a sequential Gaussian-elimination-type algorithm into the parallel, chained, load-balanced algorithm. C1 NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,HAMPTON,VA 23665. NR 10 TC 1 Z9 1 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD JUN PY 1995 VL 7 IS 4 BP 273 EP 302 DI 10.1002/cpe.4330070403 PG 30 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA RE466 UT WOS:A1995RE46600002 ER PT J AU HECK, KL ABLE, KW ROMAN, CT FAHAY, MP AF HECK, KL ABLE, KW ROMAN, CT FAHAY, MP TI COMPOSITION, ABUNDANCE, BIOMASS, AND PRODUCTION OF MACROFAUNA IN A NEW-ENGLAND ESTUARY - COMPARISONS AMONG EELGRASS MEADOWS AND OTHER NURSERY HABITATS SO ESTUARIES LA English DT Article ID MOBILE EPIBENTHIC FAUNA; SHALLOW MARINE AREAS; ZOSTERA-MARINA; WESTERN SWEDEN; SECONDARY PRODUCTION; COMMUNITY STRUCTURE; BENTHIC MACROFAUNA; WASTING DISEASE; CHESAPEAKE BAY; FOOD SELECTION AB Quantitative suction sampling was used to characterize and compare the species composition, abundance, biomass, and secondary production of macrofauna inhabiting intertidal mud-flat and sand-flat, eelgrass meadow, and salt-marsh-pool habitats in the Nauset Marsh complex, Cape God, Massachusetts (USA). Species richness and abundance were often greatest in eelgrass habitat, as was macroinvertebrate biomass and production. Most striking was the five to fifteen times greater rate of annual macrofaunal production in eelgrass habitat than elsewhere, with values ranging from approximately 23-139 g AFDW m(2) yr(-1). The marsh pool containing widgeon grass (Ruppia maritima) supported surprisingly low numbers of macroinvertebrates, probably due to stressfully low dissolved oxygen levels at night during the summer. Two species of macroinvertebrates, blue mussels (Mytilus edulis) and to a lesser extent bay scallops (Argopecten irradians), used eelgrass as ''nursery habitat.'' Calculations showed that macroinvertebrate production is proportionally much greater than the amount of primary production attributable to eelgrass in the Nauset Marsh system, and that dramatic changes at all trophic levels could be expected if large changes in seagrass abundance should occur. This work further underscores the extraordinarily large impact that seagrass can have on both the structure and function of estuarine ecosystems. C1 RUTGERS STATE UNIV,INST MARINE & COASTAL SCI,MARINE FIELD STN,TUCKERTON,NJ 08087. UNIV RHODE ISL,NATL PK SERV,COASTAL RES CTR,NARRAGANSETT,RI 02882. NATL MARINE FISHERIES SERV,SANDY HOOK LAB,HIGHLANDS,NJ 07732. RP HECK, KL (reprint author), UNIV SO ALABAMA,MARINE ENVIRONM SCI CONSORTIUM,POB 369,DAUPHIN ISL,AL 36528, USA. NR 44 TC 153 Z9 161 U1 5 U2 38 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 1995 VL 18 IS 2 BP 379 EP 389 DI 10.2307/1352320 PG 11 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA RF762 UT WOS:A1995RF76200008 ER PT J AU MLYNCZAK, MG OLANDER, DS AF MLYNCZAK, MG OLANDER, DS TI ON THE UTILITY OF THE MOLECULAR-OXYGEN DAYGLOW EMISSIONS AS PROXIES FOR MIDDLE ATMOSPHERIC OZONE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER THERMOSPHERE; MESOSPHERE; MODEL AB The molecular oxygen dayglow emissions, O-2(a(1) Delta g --> X(3) Sigma g) at 1.27 mu m and O-2(b(1) Sigma g --> X(3) Sigma g) at 762 nm, arise in pare from processes related to the Hartley band photolysis of ozone. It is therefore possible to derive daytime ozone concentrations from measurements of the volume emission rate of either dayglow. The accuracy to which the ozone concentration can be inferred depends on the accuracy to which numerous kinetic and spectroscopic rate constants are known, including rates which describe the excitation of molecular oxygen by processes that are not related to the ozone concentration. We find that several key rate constants must be known to better than 7% accuracy in order to achieve an inferred ozone concentration accurate to 15% from measurements of either dayglow. Currently, accuracies for various parameters typically range from 5% to 100%. C1 SCI APPLICAT INT CORP,HAMPTON,VA. RP MLYNCZAK, MG (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 401B,HAMPTON,VA 23681, USA. RI Mlynczak, Martin/K-3396-2012 NR 10 TC 30 Z9 30 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1995 VL 22 IS 11 BP 1377 EP 1380 DI 10.1029/95GL01321 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RB550 UT WOS:A1995RB55000016 ER PT J AU MLYNCZAK, MG NESBITT, DJ AF MLYNCZAK, MG NESBITT, DJ TI THE EINSTEIN COEFFICIENT FOR SPONTANEOUS EMISSION OF THE O-2(A(1)DELTA(G)) STATE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NEAR-INFRARED SPECTROMETER; MESOSPHERE; OZONE AB Recently reported measurements of the absorption band strength (i.e., the Einstein B-coefficient for absorption) for the transition O-2(X(3) Sigma g --> a(1) Delta g) at 1.27 mu m, when correctly reanalyzed in this paper, indicate that the Einstein A-coefficient for spontaneous emission of radiation is 1.47 x 10(-4) s(-1). This is a factor of 1.75 smaller than the value of 2.58 x 10(-4) s(-1) that has been used almost exclusively in the aeronomy field for the past 30 years. The determination of the new A-value is reviewed, with an emphasis on the derivation of the appropriate ratio of the degeneracies of the upper and lower states of this transition. The new A-value implies that ozone concentrations as inferred from measurements of O-2(a(1) Delta g) emission must be increased significantly in existing databases and also that the efficiency of solar heating in the Hartley band of ozone is larger than previously calculated. C1 UNIV COLORADO,BOULDER,CO 80309. RP MLYNCZAK, MG (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 401 B,HAMPTON,VA 23681, USA. RI Mlynczak, Martin/K-3396-2012 NR 17 TC 43 Z9 44 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1995 VL 22 IS 11 BP 1381 EP 1384 DI 10.1029/95GL01320 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RB550 UT WOS:A1995RB55000017 ER PT J AU WOO, R AF WOO, R TI SOLAR-WIND SPEED STRUCTURE IN THE INNER CORONA AT 3-12 R(O) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERPLANETARY SCINTILLATION; VELOCITY-MEASUREMENTS; TURBULENCE; EVOLUTION; STREAMERS; SUN; SPACECRAFT; MOTION; CYCLE AB Estimates of solar wind speed obtained by Armstrong et al. [1986] based on 1983 VLA multiple-station intensity scintillation measurements inside 12 R-o have been correlated with the electron density structure observed in white-light coronagraph measurements. The observed large-scale and apparently systematic speed variations are found to depend primarily on changes in heliographic latitude and longitude, which leads to the first results on large-scale speed structure in the acceleration region of the solar wind. Over an equatorial hole, solar wind speed is relatively steady, with peak-to-peak variations of 50 km/s and an average of 230 km/s. In contrast, the near-Sun flow speed across the streamer belt shows regular large-scale variations in the range of 100-300 km/s. Based on four groups of data, the gradient is 36 km/s per degree in heliocentric coordinates (corresponding to a rise of 260 km/s over a spatial distance on the Sun Of two arcmin) with a standard deviation of 2.4 km/s per degree. The lowest speeds most Likely coincide with the stalks of coronal streamers observed in white-light measurements. The detection of significant wind shear over the streamer belt is consistent with in situ and scintillation measurements showing that the density spectrum has a power-law form characteristic of fully developed turbulence over a much broader range of scales than in neighboring regions. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MS 238-737, PASADENA, CA 91109 USA. NR 33 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1995 VL 22 IS 11 BP 1393 EP 1396 DI 10.1029/95GL01315 PG 4 WC Geosciences, Multidisciplinary SC Geology GA RB550 UT WOS:A1995RB55000020 ER PT J AU KATZ, R CUCINOTTA, FA AF KATZ, R CUCINOTTA, FA TI LOW-DOSE SO HEALTH PHYSICS LA English DT Letter C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. RP KATZ, R (reprint author), UNIV NEBRASKA, LINCOLN, NE 68588 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD JUN PY 1995 VL 68 IS 6 BP 859 EP 859 PG 1 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA RA405 UT WOS:A1995RA40500018 PM 7759269 ER PT J AU BURATTI, BJ MOSHER, JA AF BURATTI, BJ MOSHER, JA TI THE DARK SIDE OF IAPETUS - ADDITIONAL EVIDENCE FOR AN EXOGENOUS ORIGIN SO ICARUS LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; SATURNIAN SATELLITES; VOYAGER PHOTOMETRY; COLOR MAPS; LAPETUS; HYPERION; ALBEDO; TETHYS; SYSTEM; PHOEBE AB The saturnian satellite Iapetus presents one of the most unusual appearances of any object in the Solar System: one hemisphere is about 10 times as bright as the other. The origin of the dark hemisphere-which reflects only a few percent of the solar radiation falling on it-has historically been one of the great puzzles of planetary science. From a map produced from previously unstudied, archived Voyager images obtained in the near ultraviolet region of the spectrum, we show that the interface between the bright and dark material is gradual. The ultraviolet (0.34 mu m) normal reflectance gradually changes from similar to 0.55 to less than 0.03 over a distance of about 1500 km. We present the first color map of Iapetus, showing there is a gradual change in color at the interface between the two hemispheres. This change is highly correlated with the change in albedo. This result supports a spectral mixing model in which the dark and bright sides are the spectral endmembers, and the interface represents a progressive enrichment of a dark red chromophore, Our results are most consistent with a model originally proposed by Cruikshank et al. (1983, Icarus 53 90-104) and Bell et al. (1985, Icarus 61, 192-207). In this model, exogenously produced material from Phoebe impacts the leading side of Iapetus and volatizes the icy component to leave a dark red lag deposit consisting of material from Phoebe and a preexisting nonvolatile constituent that is similar to the D-type material found on Hyperion and D-type asteroids. (C) 1995 Academic Press, Inc. RP BURATTI, BJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,183-501,PASADENA,CA 91109, USA. NR 38 TC 46 Z9 46 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 1995 VL 115 IS 2 BP 219 EP 227 DI 10.1006/icar.1995.1093 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RD555 UT WOS:A1995RD55500001 ER PT J AU KHANNA, RK PEARL, JC DAHMANI, R AF KHANNA, RK PEARL, JC DAHMANI, R TI INFRARED-SPECTRA AND STRUCTURE OF SOLID-PHASES OF SULFUR-TRIOXIDE - POSSIBLE IDENTIFICATION OF SOLID SO3 ON IO SURFACE SO ICARUS LA English DT Article ID FROST; REFLECTANCE; DIOXIDE; FLOWS; BAND; H2O; LO AB The IR spectra of solid sulfur trioxide (SO3) have been examined between 20 and 290 K. The spectral features of an amorphous low-temperature deposit and four additional phases (monomeric, gamma, alpha, and beta) are presented. Two of the emission peaks in the thermal spectrum of Io recorded by the Voyager IRIS instrument are suggested to be possibly due to solid SO3 mixed with crystalline SO2. (C) 1995 Academic Press, Inc. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP KHANNA, RK (reprint author), UNIV MARYLAND,DEPT CHEM & BIOCHEM,COLLEGE PK,MD 20742, USA. NR 48 TC 16 Z9 16 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 1995 VL 115 IS 2 BP 250 EP 257 DI 10.1006/icar.1995.1095 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RD555 UT WOS:A1995RD55500003 ER PT J AU HIROI, T BINZEL, RP SUNSHINE, JM PIETERS, CM TAKEDA, H AF HIROI, T BINZEL, RP SUNSHINE, JM PIETERS, CM TAKEDA, H TI GRAIN SIZES AND MINERAL COMPOSITIONS OF SURFACE REGOLITHS OF VESTA-LIKE ASTEROIDS SO ICARUS LA English DT Article ID METEORITES AB Visible and near-infrared reflectance spectra (0.4-1.0 mu m) of 21 Vesta-like asteroids and 12 HED meteorite powders (<25 mu m in grain size) have been compared, Each reflectance spectrum was deconvolved into modified Gaussians and a constant background to allow comparisons of the 1-mu m absorption band position and shape, The 1-mu m band centers and widths of Vesta-like asteroids and HED meteorites generally overlap, but asteroids have a slightly wider range of band centers and widths indicating a wider range of Fe, Mg, and Ca content of their pyroxenes. Many of the Vesta-like asteroids, however, have shallower 1-mu m absorption bands than HED meteorites. The weaker 1-mu m band suggests that the surface regoliths of those asteroids may contain a larger amount of either fine grains or plagioclase than the laboratory-prepared HED meteorite powders. The most serious spectral difference between Vesta-like asteroids and HED meteorites is their visible absorption strength (reflectance drop-off shortward of similar to 0.7 mu m) relative to the 1-mu m band strength. Vesta-like asteroids tend to have stronger visible absorption than HED meteorites. The difference in the visible absorption strength may be due to some minor transition elements (Ti, Cr, etc.) in pyroxene, other unidentified mineral components, or space weathering processes. (C) 1995 Academic Press, Inc. C1 NASA, LYNDON B JOHNSON SPACE CTR, SN3, HOUSTON, TX 77058 USA. MIT, DEPT EARTH ATMOSPHER & PLANETARY SCI, CAMBRIDGE, MA 02139 USA. SETS TECHNOL INC, MILILANI, HI 96789 USA. UNIV TOKYO, FAC SCI, INST MINERAL, TOKYO 113, JAPAN. RP HIROI, T (reprint author), BROWN UNIV, DEPT GEOL SCI, PROVIDENCE, RI 02912 USA. NR 23 TC 43 Z9 43 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JUN PY 1995 VL 115 IS 2 BP 374 EP 386 DI 10.1006/icar.1995.1105 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RD555 UT WOS:A1995RD55500013 ER PT J AU LAMB, M MA, KB COOLEY, R MACKEY, D MENG, RL CHU, CW CHU, WK CHEN, PC WILSON, T AF LAMB, M MA, KB COOLEY, R MACKEY, D MENG, RL CHU, CW CHU, WK CHEN, PC WILSON, T TI HIGH-TEMPERATURE SUPERCONDUCTING BEARINGS FOR LUNAR TELESCOPE MOUNTS SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony ID VARIABLE MAGNETIC-FIELD AB A telescope to be installed on the lunar surface in the near future must work in a cold and dusty vacuum environment for long periods without on site human maintenance. To track stars, the drive mechanism must be capable of exceedingly fine steps and repeatability. Further, the use of lightweight telescopes for obvious economic benefits burdens the requirement for stable support and rotation. Conventional contact bearings and gear drives have numerous failure modes under such a restrictive and harsh environment. However, hybrid superconducting magnetic bearings (HSMB) fit in naturally. These bearings are stable, light, passive, and essentially Frictionless, allowing high precision electronic positioning control. By passive levitation, the HSMB does not wear out and requires neither maintenance nor power. A prototype illustrating the feasability of this application is presented. C1 COMP SCI CORP,CALVERTON,MD. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP LAMB, M (reprint author), UNIV TEXAS,TEXAS CTR SUPERCONDUCT,HOUSTON,TX 77025, USA. NR 10 TC 11 Z9 11 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 638 EP 642 DI 10.1109/77.402757 PN 1 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP634 UT WOS:A1995RP63400126 ER PT J AU MAKIDA, Y ANRAKU, K SUZUKI, J YAMAMOTO, A IMORI, M YOSHIDA, T YOSHIMURA, K UEDA, I SAEKI, T MATSUNAGA, H ORITO, S MOTOKI, M NOZAKI, M YAJIMA, N RIGHTER, DL AF MAKIDA, Y ANRAKU, K SUZUKI, J YAMAMOTO, A IMORI, M YOSHIDA, T YOSHIMURA, K UEDA, I SAEKI, T MATSUNAGA, H ORITO, S MOTOKI, M NOZAKI, M YAJIMA, N RIGHTER, DL TI BALLOONING OF A THIN SUPERCONDUCTING SOLENOID FOR PARTICLE ASTROPHYSICS SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB A thin superconducting solenoid was launched by using a large balloon up to an altitude of 36.5 km in Northern Canada in the summer of 1993 as a core facility for the cosmic ray spectrometer, BESS. The magnet was excited up to 1.0 T in persistent current mode on the ground and was launched being attended with 2.7 G shocks. After 17 hours successful flight, it was discharged on the sky and made a mild descending and landing by using a parachute for recovery. The magnet was safely operated without problems during flight in 1993 and contributed to an second observation in the summer of 1994. C1 UNIV TOKYO,TOKYO,JAPAN. KOBE UNIV,KOBE,HYOGO,JAPAN. ISAS,SAGAMIHARA,KANAGAWA,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,WASHINGTON,DC 20546. RP MAKIDA, Y (reprint author), NATL LAB HIGH ENERGY PHYS,OHO 1-1,TSUKUBA,IBARAKI 305,JAPAN. RI MOTOKI, Masakazu/B-4212-2009 NR 6 TC 9 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 658 EP 661 DI 10.1109/77.402634 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP634 UT WOS:A1995RP63400130 ER PT J AU WISE, SA AMUNDSEN, RM HOPSON, P HIGH, JW KRUSE, NMH KIST, EH HOOKER, MW AF WISE, SA AMUNDSEN, RM HOPSON, P HIGH, JW KRUSE, NMH KIST, EH HOOKER, MW TI DESIGN AND TESTING OF THE MIDAS SPACEFLIGHT INSTRUMENT SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB Several applications of high temperature superconductor technology have been identified for the National Aeronautics and Space Administration's (NASA) aerospace systems. However, validation of critical superconductive properties in the space environment is necessary before this technology can be inserted into satellite systems. Researchers at NASA's Langley Research Center have designed the Materials In Devices As Superconductors (MIDAS) experiment to evaluate the electrical characteristics of high temperature superconductive materials during extended spaceflight. The MIDAS experiment will evaluate four superconductive test circuits over a temperature range of 300 to 75K. The MIDAS test circuit is produced by thick film printing and combines both superconductive and conventional electronics into a single, active microelectronics package designed to operate at cryogenic temperatures. All electrical measurements are performed directly on the test circuit, eliminating the need for intricate wiring and reducing thermal losses. This paper describes the design,fabrication, and testing of the primary subsystems of the MIDAS instrument. C1 SCI & TECHNOL CORP,HAMPTON,VA. RP WISE, SA (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 1545 EP 1548 DI 10.1109/77.402867 PN 2 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP637 UT WOS:A1995RP63700101 ER PT J AU HOOKER, MW WISE, SA HOPSON, P KRUSE, NMH HIGH, JW AF HOOKER, MW WISE, SA HOPSON, P KRUSE, NMH HIGH, JW TI OPTIMIZATION OF YBA2CU3O7-X THICK-FILMS ON YTTRIA-STABILIZED ZIRCONIA SUBSTRATES SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB This report describes the optimization of the firing process used in the production of YBa2Cu3O7-x thick films screen printed on yttris-stabilized zirconia substrates. The highest critical current density (J(c)) values were obtained by employing a double layer printing technique in which a single superconductive layer was printed onto a zirconia substrate and fired, followed by the subsequent deposition and firing of second superconductive layer. Using this procedure, thick film superconductors with superconductive transition temperature (T-c) of 85K and a J(c) of 130 A/cm(2) were obtained by sintering the printed films It 950 degrees C for 90 minutes, followed by a six hour oxygen annealing treatment at 600 degrees C. Specimens sintered for comparable periods of time at 940 and 960 degrees C did not exhibit superconductive behavior above 77K due to either incomplete microstructural development or thermal decomposition of the superconductive phase respectively. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP HOOKER, MW (reprint author), SCI & TECHNOL CORP,HAMPTON,VA 23666, USA. NR 7 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 1936 EP 1938 DI 10.1109/77.402962 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP637 UT WOS:A1995RP63700196 ER PT J AU BARNER, JB BAUTISTA, JJ BOWEN, JG CHEW, W FOOTE, MC FUJIWARA, BH GUERN, AJ HUNT, BJ JAVADI, HHS ORTIZ, GG RASCOE, DL VASQUEZ, RP WAMHOF, PD BHASIN, KB LEONARD, RF ROMANOFSKY, RR CHOREY, CM AF BARNER, JB BAUTISTA, JJ BOWEN, JG CHEW, W FOOTE, MC FUJIWARA, BH GUERN, AJ HUNT, BJ JAVADI, HHS ORTIZ, GG RASCOE, DL VASQUEZ, RP WAMHOF, PD BHASIN, KB LEONARD, RF ROMANOFSKY, RR CHOREY, CM TI DESIGN AND PERFORMANCE OF LOW-NOISE HYBRID SUPERCONDUCTOR SEMICONDUCTOR 7.4 GHZ RECEIVER DOWNCONVERTER SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB Low noise receivers play critical role in space applications. Thin film high-crtical -temperature-superconducting (HTS) passive circuits were combined with GaAs microwave devices to achieve ultra low noise and small size receiver downconverter at 77 K. HTS pre-select filter, a cryogenic mixer, and a hybrid oscillator with an HTS resonator were designed, fabricated and interconnected to produce a low-noise hybrid superconductor/semiconductor 7.4 Ghz microwave reciever. When cooled to 77K, the downconverter plus cables inside a cryogenic refrigerator had a noise figure of approximately 0.7dB with convdersion gain of 18 dB. In addition to reduce noise figure, advantages of small size and low power consumption are obsereved due to the use of HTS circuits in the downconverter. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. SVERDRUP TECHNOL INC,LERC GRP,BROOKPARK,OH 44142. RP BARNER, JB (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 4 TC 3 Z9 3 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 2075 EP 2078 DI 10.1109/77.402991 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000002 ER PT J AU SKALARE, A MCGRATH, WR BUMBLE, B LEDUC, HG BURKE, PJ VERHEIJEN, AA PROBER, DE AF SKALARE, A MCGRATH, WR BUMBLE, B LEDUC, HG BURKE, PJ VERHEIJEN, AA PROBER, DE TI A HETERODYNE RECEIVER AT 533 GHZ USING A DIFFUSION-COOLED SUPERCONDUCTING HOT-ELECTRON BOLOMETER MIXER SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB This paper describes heterodyne measurements at 533 GHz using a novel superconducting hot electron bolometer in a waveguide mixer block. The bolometer is a thin (10 nm) and narrow (0.1 mu m) strip of niobium with a length of less than half a micron and a critical temperature of approximately 5.5 K. The short length ensures that diffusion dominates over electron-phonon interaction as a cooling mechanism for the hot electrons, thus allowing heterodyne detection with intermediate frequencies of several GHz. A Y-factor response of 1.15 dB has been obtained at an intermediate frequency of 1.4 GHz with hot/cold load temperatures of approximately 295/77 K, indicating a receiver noise temperature around 650 K DSB. The IF response extends up to at least 2 GHz and possibly higher. C1 YALE UNIV,DEPT APPL PHYS,NEW HAVEN,CT 06520. RP SKALARE, A (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. RI Burke, Peter/F-3308-2010 NR 9 TC 20 Z9 20 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 2236 EP 2239 DI 10.1109/77.403030 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000041 ER PT J AU EATON, LR DURAND, DJ SANDELL, R SPARGO, JW KRABACH, T AF EATON, LR DURAND, DJ SANDELL, R SPARGO, JW KRABACH, T TI DESIGN OF A 10 K NBN A/D CONVERTER FOR IR FOCAL-PLANE ARRAY SENSORS SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB We are implementing a 12 bit SFQ counting ADC with parallel-to-serial readout using our established 10 K NbN capability. This circuit provides a key element of the analog signal processor (ASP) used in large infrared focal plane arrays. The circuit processes the signal data stream from a Si:As BIB detector array. A 10 mega samples per second (MSPS) pixel data stream flows from the chip at a 120 megabit bit rate in a format that is compatible with other superconductive time dependent processor (TDP) circuits being developed. We will discuss our planned ASP demonstration, the circuit design, and test results. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP EATON, LR (reprint author), TRW CO INC,1 SPACE PK,REDONDO BEACH,CA 90278, USA. NR 4 TC 4 Z9 4 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 2457 EP 2460 DI 10.1109/77.403088 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000095 ER PT J AU MUELLER, CH MIRANDA, FA TONCICH, SS BHASIN, KB AF MUELLER, CH MIRANDA, FA TONCICH, SS BHASIN, KB TI YBCO X-BAND MICROSTRIP LINEAR RESONATORS ON (1(1)OVER-BAR-02)-ORIENTED AND (1(1)OVER-BAR-00)-ORIENTED SAPPHIRE SUBSTRATES SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony ID PERMITTIVITY AB YBa2Cu3O7-delta (YBCO) films on sapphire substrates have been tested for planar microwave applications such as filters and resonators, We have measured the unloaded quality factors (Q(o)) of X-band microstrip linear resonators patterned into YBCO films on R-plane (1 (1) over bar 02-oriented) and M-plane (1 (1) over bar 00-oriented) sapphire substrates with CeO2, and MgO buffer layers, respectively. For the films on M-plane sapphire, the T-c and x-ray FWHM values were 87-88 K and 1.2 degrees, respectively, while for those on R-plane sapphire the values were 88-89 K and 0.4 degrees. Despite the superior properties of the films on R-plane, the YBCO on M-plane sapphire resonators had Q(o) values over 2000 at 77 K while those on R-plane sapphire had Q(o) values of less than 600. This could be correlated with the anisotropy of the R-plane sapphire as evidenced by the observed dependence of the shape of the resonance on the orientation of the resonator relative to the in-plane direction of the substrates. Possible causes for this behavior will be discussed. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 7 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 2559 EP 2562 DI 10.1109/77.403112 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000120 ER PT J AU ZMUIDZINAS, J UGRAS, NG MILLER, D GAIDIS, M LEDUC, HG STERN, JA AF ZMUIDZINAS, J UGRAS, NG MILLER, D GAIDIS, M LEDUC, HG STERN, JA TI LOW-NOISE SLOT ANTENNA SIS MIXERS SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony ID RADIO ASTRONOMY; RECEIVER; MILLIMETER; WAVE AB We describe quasi-optical SIS mixers operating in the submillimeter band (500-750 GHz) which have very low noise, around 5 h nu/k(B) for the double-sideband receiver noise temperature. The mixers use a twin-slot antenna, Nb/Al-Oxide/Nb tunnel junctions fabricated with optical lithography, a two-junction tuning circuit, and a silicon hyperhemispherical lens with a novel antireflection coating to optimize the optical efficiency We have flown a submillimeter receiver using these mixers on the Kuiper Airborne Observatory, and have detected a transition of (H2O)-O-18 at 745 GHz. This directly confirms that SIS junctions are capable of low-noise mixing above the gap frequency. RP ZMUIDZINAS, J (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. RI Gaidis, Michael/D-3327-2013 NR 20 TC 34 Z9 34 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 3053 EP 3056 DI 10.1109/77.403236 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000244 ER PT J AU MIRANDA, FA MUELLER, CH CUBBAGE, CD BHASIN, KB SINGH, RK HARKNESS, SD AF MIRANDA, FA MUELLER, CH CUBBAGE, CD BHASIN, KB SINGH, RK HARKNESS, SD TI HTS FERROELECTRIC THIN-FILMS FOR TUNABLE MICROWAVE COMPONENTS SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1994 Applied Superconductivity Conference CY OCT 16-21, 1994 CL BOSTON, MA SP MIT, Plasma Fus Ctr, Dept Elect Engn & Comp Sci, US DOE, Off Fus Energy, High Energy Phys, Adv Res Projects Agcy, Natl Inst Stand & Technol, USN, Naval Res Lab, USN, Off Naval Res, Quantum Magnet, IGC Adv Superconductors, Stone & Webster Engn Corp, Technova, Martin Marietta Astronaut, Walker Sci Inc, Westinghouse Sci & Technol Ctr, Babcock & Wilcox, Bechtel Corp, Cosine, Inc, Synchrony AB We report on the electrical characterization of Ba0.5Sr0.5TiO3/YBa2Cu3O7-delta/LaAlO3 multilayer structure, This structure was fabricated using a pulsed laser deposition technique yielding film thicknesses of 300 nm and 800 nm for the YBa2Cu3O7-delta (YBCO) and the Ba0.5Sr0.5TiO3(BST) films, respectively, A transition temperature T-c=91.5 K was measured for the YBCO film in this structure after deposition of the BST layer. The structure was patterned into parallel plate capacitors with 400x400 mu m gold contacts and YBCO electrodes on top and underneath the BST, respectively. A relative dielectric constant (epsilon(r)) similar to 425 and a loss tangent (tan delta) = 0.040 were measured at 1.0 MHz at 298 K and zero dc voltage (V-dc=0 volts). At 77 K, the dielectric data showed 320 less than or equal to epsilon(r) less than or equal to 360 and tanS=0.036 at V-dc= 0 volts. For 5.0 greater than or equal to V-dc greater than or equal to 3.0 volts epsilon(r) could be varied from 180 to 370. For -5.0 less than or equal to V-dc less than or equal to 3.0 volts, epsilon(r) decreased rapidly with little change in tan delta. The epsilon(r) versus V-dc data suggest that changes in epsilon(r) were affected by electrode space charge layers. C1 UNIV FLORIDA,GAINESVILLE,FL 32611. RP MIRANDA, FA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 8 TC 33 Z9 35 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1995 VL 5 IS 2 BP 3191 EP 3194 DI 10.1109/77.403270 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RP640 UT WOS:A1995RP64000278 ER PT J AU SHAH, B HOLMES, JK HINEDI, S AF SHAH, B HOLMES, JK HINEDI, S TI COMPARISON OF 4 FFT-BASED FREQUENCY ACQUISITION TECHNIQUES FOR COSTAS LOOP BPSK SIGNAL DEMODULATION SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article AB This paper discussed four open-loop frequency acquisition techniques for suppressed-carrier BPSK signals, The techniques, which do not require accurate symbol timing nor a data preamble sequence, employ fast Fourier transforms (FFT's) on the Costas loop phase detector output to detect the Doppler frequency offset. Performance of the full-, half-, and staggered-symbol integration techniques as well as the low-pass filter technique are compared in terms of the error signal output SNR's, Then, the probability of detecting the frequency offset is computed for the special case when the frequency of the tone to be detected coincides with one of the FFT-bin center frequencies, It is shown that the performance of the integration techniques depends strongly on the symbol timing offset. On the other hand, the detection probability for the one-pole arm filter technique depends directly on the filter bandwidth, The staggered integration technique Is shown to have comparable performance to the lowpass filter technique for low-to-medium symbol SNR's but the latter is superior at high symbol SNR's. C1 AEROSP CORP,LOS ANGELES,CA 90009. RP SHAH, B (reprint author), CALTECH,JET PROP LAB,COMMUN SYST RES SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 12 TC 2 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD JUN PY 1995 VL 43 IS 6 BP 2157 EP 2167 DI 10.1109/26.387457 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA RC619 UT WOS:A1995RC61900021 ER PT J AU WU, J DAS, R SALTZ, J BERRYMAN, H HIRANANDANI, S AF WU, J DAS, R SALTZ, J BERRYMAN, H HIRANANDANI, S TI DISTRIBUTED-MEMORY COMPILER DESIGN FOR SPARSE PROBLEMS SO IEEE TRANSACTIONS ON COMPUTERS LA English DT Article DE PARALLEL COMPUTING; DISTRIBUTED MEMORY; COMPILER; IRREGULAR PROBLEMS; DATA PARALLEL LANGUAGE ID FACTORIZATION; EXECUTION; MACHINES AB This paper addresses the issue of compiling concurrent loop nests in the presence of complicated array references and irregularly distributed arrays. Arrays accessed within loops may contain accesses that make it impossible to precisely determine the reference pattern at compile time. This paper proposes a run time support mechanism that is used effectively by a compiler to generate efficient code in these situations. The compiler accepts as input a Fortran 77 program enhanced with specifications for distributing data, and outputs a message passing program that runs on the nodes of a distributed memory machine. The runtime support for the compiler consists of a library of primitives designed to support irregular patterns of distributed array accesses and irregularly distributed array partitions. A variety of performance results on the Intel iPSC/860 are presented. C1 UNIV MARYLAND, DEPT COMP SCI, COLLEGE PK, MD 20742 USA. RICE UNIV, DEPT COMP SCI, HOUSTON, TX 77251 USA. NASA, LANGLEY RES CTR, ICASE, HAMPTON, VA 23665 USA. RP WU, J (reprint author), YALE UNIV, DEPT COMP SCI, NEW HAVEN, CT 06520 USA. NR 43 TC 15 Z9 15 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9340 J9 IEEE T COMPUT JI IEEE Trans. Comput. PD JUN PY 1995 VL 44 IS 6 BP 737 EP 753 DI 10.1109/12.391186 PG 17 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA RE008 UT WOS:A1995RE00800001 ER PT J AU PALJUG, E YUN, XP AF PALJUG, E YUN, XP TI EXPERIMENTAL-STUDY OF 2 ROBOT ARMS MANIPULATING LARGE OBJECTS SO IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY LA English DT Article ID ARCHITECTURE AB In this paper, we present the architecture of an experimental real-time control system called TRACS (two robotic arm coordination system) and experimental results using two PUMA 250 robot arms that perform tasks of manipulating large objects. The system uses an IBM PC-AT as the host computer which is equipped with an AMD29000 high speed floating point coprocessor. It is configured in such a way that the Intel 80286 processor performs all the input-output interface operations (interface to the sensors, arms, and user) while the AMD29000 carries out the real-time computations of feedback control algorithms, Using the system, we have successfully implemented the dynamic control algorithm developed for coordinating two robotic arms, The two arms perform the task of manipulating a large object by means of enveloping grasp. The coordinated control algorithm utilizes the full dynamics of the two arms, The results from two experimental tasks are described in detail, in which the two arms move an object while adapting the grasp configuration to the motion trajectory and to the external disturbance force. C1 USN,POSTGRAD SCH,DEPT ELECT & COMP ENGN,MONTEREY,CA 93943. RP PALJUG, E (reprint author), CALTECH,JET PROP LAB,MAN MACHINES SYST GRP,PASADENA,CA 91109, USA. NR 45 TC 4 Z9 5 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 1063-6536 J9 IEEE T CONTR SYST T JI IEEE Trans. Control Syst. Technol. PD JUN PY 1995 VL 3 IS 2 BP 177 EP 188 DI 10.1109/87.388126 PG 12 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA RA651 UT WOS:A1995RA65100003 ER PT J AU KARADY, GG ROY, RR DOMITZ, S AF KARADY, GG ROY, RR DOMITZ, S TI EFFECT OF TEMPERATURE ON THE PARTIAL DISCHARGE INITIATION VOLTAGE OF CAPACITORS SO IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION LA English DT Note AB The paper describes a novel test arrangement to characterize the temperature dependence of partial discharge (PD) inception voltage in capacitors. The test arrangement consist of a temperature chamber, HV supply and PD detection circuit. The corona free operation voltage is 0 to 3.6 kV, temperature range is -50 to 200 degrees C. Different type of capacitors PD inception voltage were measured at different temperatures. It was found that most commercial capacitor PD was lower than the rated voltage and increased by the temperature. In contrast, the higher quality chip type ceramic capacitor PD was above the rated voltage and decreased with the temperature. The paper concludes that the prediction of capacitor performance requires the measurement of PD at different temperatures. C1 NASA,WASHINGTON,DC 20546. RP KARADY, GG (reprint author), ARIZONA STATE UNIV,DEPT ELECT ENGN,TEMPE,AZ 85287, USA. NR 7 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 1070-9878 J9 IEEE T DIELECT EL IN JI IEEE Trns. Dielectr. Electr. Insul. PD JUN PY 1995 VL 2 IS 3 BP 499 EP 502 DI 10.1109/94.395411 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA RK030 UT WOS:A1995RK03000019 ER PT J AU OTOSHI, TY AF OTOSHI, TY TI SIMULATION DIAGNOSTICS OF MULTIPLE DISCONTINUITIES IN A MICROWAVE COAXIAL TRANSMISSION-LINE SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article AB Multiple discontinuities in microwave transmission lines can cause unusual reflection and transmission loss characteristics as functions of frequency. This article presents a method for developing models that simulate return loss and insertion loss data measured over a broad band of frequencies. The overall cable is modeled as a coaxial transmission line consisting of shunt susceptance discontinuities separated by line lengths. A nonlinear least-squares fit is then performed between theoretical data (from the model) and experimental data. When this method was applied to modeling discontinuities in a slightly damaged S-band antenna cable, excellent agreement between theory and experiment was obtained over a frequency range of 1.70-2.85 GHz. RP OTOSHI, TY (reprint author), JET PROP LAB,PASADENA,CA 91109, USA. NR 8 TC 0 Z9 0 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JUN PY 1995 VL 43 IS 6 BP 1310 EP 1314 DI 10.1109/22.390188 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA RD064 UT WOS:A1995RD06400016 ER PT J AU CALLAS, JL MAHONEY, WA SKELTON, RT VARNELL, LS WHEATON, WA AF CALLAS, JL MAHONEY, WA SKELTON, RT VARNELL, LS WHEATON, WA TI GAMMA-RAY IMAGING LABORATORY MEASUREMENTS USING EXTERNALLY SEGMENTED GERMANIUM DETECTORS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article AB Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy using an externally segmented germanium sensor has been demonstrated in the laboratory with a calibrated radioactive source. The system employs a single high-purity coaxial detector with its outer electrode segmented into five distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A nonnegative, linear least-squares algorithm was then employed to reconstruct a two-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process. RP CALLAS, JL (reprint author), CALTECH,JET PROP LAB,HIGH ENERGY ASTROPHYS GRP,PASADENA,CA 91109, USA. NR 16 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD JUN PY 1995 VL 42 IS 3 BP 121 EP 129 DI 10.1109/23.387351 PG 9 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA QZ853 UT WOS:A1995QZ85300002 ER PT J AU FIJANY, A SHARF, I DELEUTERIO, GMT AF FIJANY, A SHARF, I DELEUTERIO, GMT TI PARALLEL O(LOG-N) ALGORITHMS FOR COMPUTATION OF MANIPULATOR FORWARD DYNAMICS SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article ID ROBOT; FORMULATION; SIMULATION AB In this paper, parallel O(log N) algorithms for computation of manipulator forward dynamics are developed, These parallel algorithms are based on a new O(N) solution to the problem, The underlying feature of this O(N) method is a different strategy for decomposition of interbody force which results in a new factorization of mass matrix (M). Specifically, a factorization of inverse of the mass matrix in the form of Schur Complement is derived as M(-1) = C - B-t A(-1) B wherein A,B, and C are block tridiagonal matrices. The new O(N) algorithm is then derived as a recursive implementation of this factorization of M(-1). It is shown that the resulting algorithm is strictly parallel, that is, it is less efficient than other methods for serial computation of the problem, However, it is the first known algorithm that can be parallelized to derive a both time- and processor-optimal parallel algorithm for the problem, i.e., a parallel O(log N) algorithm with O(N) processors, Strategies for multilevel exploitation of parallelism in the computation are also discussed, resulting in more efficient parallel O(log N) algorithms, The parallel algorithms developed in this paper, in addition to their theoretical significance, are also important from a practical implementation standpoint due to their simple architectural requirements. C1 UNIV VICTORIA, DEPT MECH ENGN, VICTORIA, BC V8W 3P6, CANADA. UNIV TORONTO, INST AEROSP STUDIES, SPACE ROBOT GRP, DOWNSVIEW, ON M3H 5T6, CANADA. RP CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. NR 40 TC 54 Z9 55 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD JUN PY 1995 VL 11 IS 3 BP 389 EP 400 DI 10.1109/70.388780 PG 12 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA RC434 UT WOS:A1995RC43400007 ER PT J AU GLASS, K COLBAUGH, R LIM, D SERAJI, H AF GLASS, K COLBAUGH, R LIM, D SERAJI, H TI REAL-TIME COLLISION-AVOIDANCE FOR REDUNDANT MANIPULATORS SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Note ID INVERSE KINEMATIC SOLUTIONS; CONFIGURATION CONTROL; OBSTACLE AVOIDANCE; ROBOTS AB This paper presents a simple and robust approach to achieving collision avoidance for kinemetically redundant manipulators at the control-loop level. The proposed scheme represents the obstacle avoidance requirement as inequality constraints in the manipulator workspace, and ensures that these inequalities are satisfied while the end-effector tracks the desired trajectory. The control scheme is the damped-least-squares formulation of the configuration control approach implemented as a kinematic controller. Computer simulation and experimental results are given for a Robotics Research 7 DOF redundant arm and demonstrate the collision avoidance capability for reaching inside a truss structure. These results confirm that the proposed approach provides a simple and effective method for real-time collision avoidance. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP NEW MEXICO STATE UNIV, DEPT MECH ENGN, LAS CRUCES, NM 88003 USA. NR 18 TC 42 Z9 43 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD JUN PY 1995 VL 11 IS 3 BP 448 EP 457 DI 10.1109/70.388789 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA RC434 UT WOS:A1995RC43400016 ER PT J AU FORSSELL, LK COHEN, SD AF FORSSELL, LK COHEN, SD TI USING LINE INTEGRAL CONVOLUTION FOR FLOW VISUALIZATION - CURVILINEAR GRIDS, VARIABLE-SPEED ANIMATION, AND UNSTEADY FLOWS SO IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS LA English DT Article DE FLOW VISUALIZATION; VECTOR FIELD VISUALIZATION; LINE INTEGRAL CONVOLUTION; CURVILINEAR GRIDS; FLOW ANIMATION; UNSTEADY FLOWS AB Line Integral Convolution (LIC), introduced by Cabral and Leedom in SIGGRAPH) '93, is a powerful technique for imaging and animating vector fields. We extend the LIC technique in three ways: 1. The existing algorithm is limited to vector fields over a regular Cartesian grid. We extend the algorithm and the animation techniques possible with it to vector fields over curvilinear surfaces, such as those found in computational fluid dynamics simulations. 2. We introduce a technique to visualize vector magnitude as well as vector direction, i.e., variable-speed flow animation. 3. We show how to modify LIC to visualize unsteady (time dependent) flows. Our implementation utilizes texture-mapping hardware to run in real time, which allows our algorithms to be included in interactive applications. C1 NASA, AMES RES CTR, COMP SCI CORP, MOFFETT FIELD, CA 94035 USA. RP FORSSELL, LK (reprint author), STANFORD UNIV, STANFORD, CA 94305 USA. NR 21 TC 66 Z9 67 U1 2 U2 10 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1077-2626 J9 IEEE T VIS COMPUT GR JI IEEE Trans. Vis. Comput. Graph. PD JUN PY 1995 VL 1 IS 2 BP 133 EP 141 DI 10.1109/2945.468406 PG 9 WC Computer Science, Software Engineering SC Computer Science GA RV868 UT WOS:A1995RV86800005 ER PT J AU BANKS, DC SINGER, BA AF BANKS, DC SINGER, BA TI A PREDICTOR-CORRECTOR TECHNIQUE FOR VISUALIZING UNSTEADY-FLOW SO IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS LA English DT Article DE VORTEX IDENTIFICATION; VORTEX VISUALIZATION; NUMERICAL FLOW VISUALIZATION; NUMERICAL FLOW ANIMATION; VORTEX CORE; DATA REDUCTION; FEATURE EXTRACTION ID TURBULENT CHANNEL FLOW; VORTICITY FIELD; BOUNDARY-LAYER AB We present a method for visualizing unsteady flow by displaying its vortices. The vortices are identified by using a vorticity-predictor pressure-corrector scheme that follows vortex cores. The cross-sections of a vortex at each point along the core can be represented by a Fourier series. A vortex can be faithfully reconstructed from the series as a simple quadrilateral mesh, or its reconstruction can be enhanced to indicate helical motion. The mesh can reduce the representation of the flow features by a factor of one thousand or more compared with the volumetric dataset. With this amount of reduction it is possible to implement an interactive system on a graphics workstation to permit a viewer to examine, in three dimensions, the evolution of the vortical structures in a complex, unsteady flow. C1 NASA, LANGLEY RES CTR, HIGH TECHNOL CORP, HAMPTON, VA 23681 USA. RP NASA, LANGLEY RES CTR, INST COMP APPLICAT SCI & ENGN, MS 132C, HAMPTON, VA 23681 USA. NR 35 TC 80 Z9 80 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1077-2626 EI 1941-0506 J9 IEEE T VIS COMPUT GR JI IEEE Trans. Vis. Comput. Graph. PD JUN PY 1995 VL 1 IS 2 BP 151 EP 163 DI 10.1109/2945.468404 PG 13 WC Computer Science, Software Engineering SC Computer Science GA RV868 UT WOS:A1995RV86800007 ER PT J AU LOVE, SG BROWNLEE, DE KING, NL HORZ, F AF LOVE, SG BROWNLEE, DE KING, NL HORZ, F TI MORPHOLOGY OF METEOROID AND DEBRIS IMPACT CRATERS FORMED IN SOFT METAL TARGETS ON THE LDEF SATELLITE SO INTERNATIONAL JOURNAL OF IMPACT ENGINEERING LA English DT Article ID KM S AB We have measured the depths, average diameters and circularity indices of over 600 micrometeoroid and space debris impact craters formed in surfaces exposed to space aboard the Long Duration Exposure Facility satellite. The target surfaces had a variety of orientations and physical properties. The average depth-diameter ratio of craters formed in aluminum targets by nearly normal impacts is between 0.56 and 0.60, higher than the canonical and widely accepted value of 0.50 which corresponds to a hemispherical shape. The depth-diameter ratio does not change significantly with target Brinell hardness values between 40 and 90, or with average impact velocity above 5 km s(-1). The depth-diameter ratio is found to vary as roughly the one-tenth power of target density. Less than 10% of the craters examined had major-to-minor axis ratios higher than 1.5, consistent with the production of shallow, elongated craters exclusively by grazing impacts. The variation in depth-diameter ratio for circular craters most likely results from variation in projectile shapes. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV SOLAR SYST EXPLORAT SN4,HOUSTON,TX 77058. RP LOVE, SG (reprint author), UNIV WASHINGTON,DEPT ASTRON FM20,SEATTLE,WA 98195, USA. NR 39 TC 25 Z9 25 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0734-743X J9 INT J IMPACT ENG JI Int. J. Impact Eng. PD JUN PY 1995 VL 16 IS 3 BP 405 EP 418 DI 10.1016/0734-743X(94)00050-7 PG 14 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA RF719 UT WOS:A1995RF71900004 ER PT J AU FARHOOMAND, J MCMURRAY, RE HALLER, E BAUSER, E SILIER, I AF FARHOOMAND, J MCMURRAY, RE HALLER, E BAUSER, E SILIER, I TI CHARACTERIZATION OF HIGH-PURITY GAAS FAR-INFRARED PHOTOCONDUCTORS SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article AB In this paper we report the results of an extensive study on the far-infrared photoconductivity of high purity n-type GaAs. The crystal, which was grown at Max-Plank-Institute for Solid State Physics using liquid-phase epitaxy, exhibited the fine structures of the excited state transitions of the residual shallow level impurities. The major peak in the spectral response belongs to the 1s-2p transition, with its responsivity about thirty five times higher than the continuum. At 3.4K detector temperature, 625 mV bias, and 100 Hz chopping frequency the detector responsivity at 35.4 cm(-1) (279 mu m) was measured to be 0.017 A/W. Under these same conditions, the NEP was 5.9x10(-14) W/root Hz. The (DC) dark current at 25 mV bias was 5.6x10(-14) A. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA. MAX PLANCK INST SOLID STATE PHYS,STUTTGART,GERMANY. RP FARHOOMAND, J (reprint author), ORION TECHNOSCI INC,PALO ALTO,CA, USA. NR 5 TC 3 Z9 3 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD JUN PY 1995 VL 16 IS 6 BP 1051 EP 1064 DI 10.1007/BF02068276 PG 14 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA RF600 UT WOS:A1995RF60000006 ER PT J AU COLBAUGH, R SERAJI, H GLASS, K AF COLBAUGH, R SERAJI, H GLASS, K TI ADAPTIVE COMPLIANT MOTION CONTROL FOR DEXTEROUS MANIPULATORS SO INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH LA English DT Note ID REDUNDANT MANIPULATORS; ROBOT MANIPULATORS; IMPEDANCE CONTROL; SYSTEMS AB This article presents two adaptive schemes for compliant motion control of dexterous manipulators. The first scheme is developed using an adaptive impedance control approach for torque-controlled manipulators, whereas the second strategy is an adaptive admittance controller for position-controlled manipulators. The proposed controllers are very general and computationally efficient, as they do not require knowledge of the manipulator dynamic model or parameter values of the manipulator or the environment and are implemented without calculation of the inverse dynamics or inverse kinematic transformation. It is shown that the control strategies are globally stable in the presence of bounded disturbances and that in the absence of disturbances the ultimate bound on the size of the system errors can be made arbitrarily small. The capabilities of the proposed control schemes are illustrated through both computer simulations and laboratory experiments with a dexterous Robotics Research Corporation Seven-degrees-of-freedom (DOF) manipulator. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP COLBAUGH, R (reprint author), NEW MEXICO STATE UNIV,DEPT MECH ENGN,LAS CRUCES,NM 88003, USA. NR 17 TC 32 Z9 33 U1 0 U2 3 PU MIT PRESS PI CAMBRIDGE PA 55 HAYWARD ST JOURNALS DEPT, CAMBRIDGE, MA 02142 SN 0278-3649 J9 INT J ROBOT RES JI Int. J. Robot Res. PD JUN PY 1995 VL 14 IS 3 BP 270 EP 280 DI 10.1177/027836499501400305 PG 11 WC Robotics SC Robotics GA QY661 UT WOS:A1995QY66100005 ER PT J AU ABOUDI, J PINDERA, MJ ARNOLD, SM AF ABOUDI, J PINDERA, MJ ARNOLD, SM TI THERMO-INELASTIC RESPONSE OF FUNCTIONALLY GRADED COMPOSITES SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article AB A recently developed micromechanical theory for the thermo-elastic response of functionally graded composites is further extended to include the inelastic and temperature-dependent response of the constituent phases. In contrast to currently employed micromechanical approaches applied to this newly emerging class of materials, which decouple the local and global effects by assuming the existence of a representative volume element at every point within the composite, the new theory explicitly couples the local and global effects. Previous thermo-elastic analysis has demonstrated that such coupling is necessary when: the temperature gradient is large with respect to the dimension of the inclusion phase; the characteristic dimension of the inclusion phase is large relative to the global dimensions of the composite; and the number of inclusions is small. In these circumstances, the concept of the representative volume element is no longer applicable and the standard micromechanical analyses based on this concept produce questionable results. Examples of composite materials that fall into this category include large-diameter fiber composites such as SiC/Ti and B/Al. Herein, we extend this new approach to include the inelastic and temperature-dependent response of the constituent phases in order to be able to realistically model functionally graded metal matrix composites in the presence of large temperature gradients. The inelastic behavior of the matrix phase is modeled using two inelastic models, namely the Bodner-Partom unified viscoplasticity theory and the classical incremental plasticity theory. Results are presented that illustrate the differences between elastic and inelastic analyses, defining under what circumstances the inclusion of inelastic effects is important. Application of the theory to composites with thermal barrier coatings demonstrates the utility of the concept of internal temperature management through functional grading of the microstructure using differently-distributed particulate inclusions. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. UNIV VIRGINIA,CHARLOTTESVILLE,VA. NR 16 TC 38 Z9 41 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD JUN PY 1995 VL 32 IS 12 BP 1675 EP 1710 DI 10.1016/0020-7683(94)00201-7 PG 36 WC Mechanics SC Mechanics GA QV486 UT WOS:A1995QV48600003 ER PT J AU GRETEBECK, RJ SCHOELLER, DA GIBSON, EK LANE, HW AF GRETEBECK, RJ SCHOELLER, DA GIBSON, EK LANE, HW TI ENERGY-EXPENDITURE DURING ANTIORTHOSTATIC BED REST (SIMULATED MICROGRAVITY) SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE DOUBLY LABELED WATER; BASAL ENERGY EXPENDITURE; RESTING ENERGY EXPENDITURE; SEDENTARY ID PREDICTION EQUATION; SPACE-FLIGHT; REQUIREMENTS; WATER; O-18 AB Few studies have addressed the interaction between energy balance and lean body mass in healthy subjects during spaceflight or its simulations. We used doubly labeled water to measure total energy expenditure (TEE) in nine healthy adult men during two 7-day periods, once before and once during a 10-day head-down bed-rest period. Mean TEE was 21% less during than before bed rest; however, neither basal (BEE) nor resting (REE) energy expenditures changed, implying that the lesser TEE resulted from a reduction in physical activity. During the bed-rest period, energy intake was 563 +/- 280 kcal/day higher than TEE (P < 0.05) but body weight, fluid balance, BEE, and REE did not change relative to before bed rest. However, the small but statistically significant increase in body fat (0.44 +/- 0.67 kg, P < 0.05) during the bed-rest period suggests that body weight alone does not accurately reflect changes in energy balance during antiorthostatic bed rest. C1 UNIV CHICAGO,DEPT MED,CHICAGO,IL 60637. NASA,SPACE & LIFE SCI DIRECTORATE,NUTR BIOCHEM & STABLE ISOTOPE LABS,HOUSTON,TX 77058. UNIV CHICAGO,DEPT MED,CHICAGO,IL 60637. RP GRETEBECK, RJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,UNIV SPACE RES ASSOC,MAIL CODE SD4,HOUSTON,TX 77058, USA. NR 18 TC 42 Z9 43 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD JUN PY 1995 VL 78 IS 6 BP 2207 EP 2211 PG 5 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA RD347 UT WOS:A1995RD34700029 PM 7665419 ER PT J AU KYLLING, A STAMNES, K TSAY, SC AF KYLLING, A STAMNES, K TSAY, SC TI A RELIABLE AND EFFICIENT 2-STREAM ALGORITHM FOR SPHERICAL RADIATIVE-TRANSFER - DOCUMENTATION OF ACCURACY IN REALISTIC LAYERED MEDIA SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE RADIATIVE TRANSFER; SPHERICAL GEOMETRY; PHOTODISSOCIATION; PHOTOLYSIS; J-VALUES; WARMING COOLING; CLOUDS; AEROSOLS; ERRORS; 2-STREAM; ALGORITHM ID VERTICALLY INHOMOGENEOUS ATMOSPHERES; MULTIPLE-SCATTERING; PHOTODISSOCIATION; FLUX; APPROXIMATIONS; EQUATION; CLOUDS; OZONE AB We present a fast and well documented two-stream algorithm for radiative transfer and particle transport in vertically inhomogeneous, layered media. The physical processes considered are internal production (emission), scattering, absorption, and Lambertian refection at the lower boundary. The medium may be forced by internal sources as well as by parallel or uniform incidence at the top boundary. This two-stream algorithm is based on a general purpose multi-stream discrete ordinate algorithm released previously. It incorporates all the advanced features of this well-tested and unconditionally stable algorithm, and includes two new features: (i) corrections for spherical geometry, and (ii) an efficient treatment of internal sources that vary rapidly with depth. It may be used to compute fluxes, flux divergences and mean intensities (actinic fluxes) at any depth in the medium. We have used the numerical code to investigate the accuracy of the two-stream approximation in vertically inhomogeneous media. In particular, computations of photodissociation and warming/cooling rates and surface fluxes of ultraviolet and visible radiation for clear, cloudy and aerosol-loaded atmospheres are presented and compared with results from multi-stream computations. The O-3 + hv --> O(D-1) + O-2 and O-3 + hv --> 0(P-3) + O-2 photodissociation rates were considered for solar zenith angles between 0.0-70.0 degrees and surface albedos in the range 0.0-1.0. For small and moderate values of the solar zenith angle and the surface albedo the error made by the two-stream approximation is generally smaller, < 10%, than the combined uncertainty in cross sections and quantum yields. Surface ultraviolet and visible fluxes were calculated for the same range of solar zenith angles and surface albedos as the photodissociation rates. It was found that surface ultraviolet and visible fluxes may be calculated by the two-stream approximation with 10% error or less for solar zenith angles less than 60.0 degrees and surface albedos less than 0.5. For large solar zenith angles and/or large surface albedos, conditions typical at high latitudes, the error made by the two-stream approximation may become appreciable, i.e. 20% or more for the photodissociation rates in the lower stratosphere and for ultraviolet and visible surface fluxes for large surface albedos. The two-stream approximation agrees well with multi-stream results for computation of warming/cooling rates except for layers containing cloud and aerosol particles where errors up to 10% may occur. The numerical code provides a fast, well-tested and robust two-stream radiative transfer program that can be used as a 'software tool' by aeronomers, atmospheric physicists and chemists, climate modellers, meteorologists, photobiologists and others concerned with radiation or particle transport problems. Copies of the FORTRAN77 program are available to interested users. C1 NASA,GODDARD SPACE FLIGHT CTR,CLIMATE & RADIAT BRANCH,GREENBELT,MD 20771. RP KYLLING, A (reprint author), UNIV ALASKA,INST GEOPHYS,POB 757320,903 KOYUKUK DR,FAIRBANKS,AK 99775, USA. RI Tsay, Si-Chee/J-1147-2014; Kylling, Arve/B-1137-2017 OI Kylling, Arve/0000-0003-1584-5033 NR 40 TC 93 Z9 95 U1 0 U2 3 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 JUN PY 1995 VL 21 IS 2 BP 115 EP 150 DI 10.1007/BF00696577 PG 36 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA TA044 UT WOS:A1995TA04400002 ER PT J AU KEPPENNE, CL AF KEPPENNE, CL TI AN ENSO SIGNAL IN SOYBEAN FUTURES PRICES SO JOURNAL OF CLIMATE LA English DT Note ID NINO-SOUTHERN OSCILLATION; SINGULAR-SPECTRUM ANALYSIS; INTRASEASONAL OSCILLATIONS; STATISTICAL-MODELS; GLOBAL ATMOSPHERE; TIME-SERIES; HEMISPHERE; DYNAMICS; DROUGHT; EVENTS AB An example of socioeconomic repercussions of the El Nino-Southern Oscillation (ENSO) is examined. Multichannel singular spectrum analysis, a variant of principal component analysis useful in isolating the spatial and temporal variability associated with anharmonic oscillations, is applied to normalized monthly mean time series of soybean futures prices and the Southern Oscillation index. The method isolates the variability common to the two time series from the remaining variability and noise. It identifies the low- and high-frequency, quasibiennial modes of ENSO as part of this variability. RP KEPPENNE, CL (reprint author), CALTECH,JET PROP LAB,MAIL STOP 238-332,PASADENA,CA 91109, USA. NR 35 TC 16 Z9 16 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 JUN PY 1995 VL 8 IS 6 BP 1685 EP 1689 DI 10.1175/1520-0442(1995)008<1685:AESISF>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RE737 UT WOS:A1995RE73700017 ER PT J AU LATHERS, CM SCHRAEDER, PL AF LATHERS, CM SCHRAEDER, PL TI EXPERIENCE-BASED TEACHING OF THERAPEUTICS AND CLINICAL-PHARMACOLOGY OF ANTIEPILEPTIC DRUGS, SUDDEN UNEXPLAINED DEATH IN EPILEPSY - DO ANTIEPILEPTIC DRUGS HAVE A ROLE SO JOURNAL OF CLINICAL PHARMACOLOGY LA English DT Article ID CARDIAC NEURAL DISCHARGE; EPILEPTOGENIC ACTIVITY; AUTONOMIC DYSFUNCTION; UNEXPECTED DEATH; ARRHYTHMIAS; SEIZURES; DIGITALIS; CAT AB The contents of this paper have been written to be used in a teaching program specifically designed for medical postgraduate education of resident physicians and fellows in training interested in the clinical pharmacology of antiepileptic drugs and their role in the treatment of epilepsy and/or in the prevention of sudden unexpected death associated with this disease. With some modifications, such as a specific lecture to provide an overview of the numerous concepts presented in the text, the article could be used when teaching fourth-year medical students. The format of the paper is a combination of didactic review and eight case reports in a self-learning format. A quiz for self-assessment is included at the end of the article (see Appendix). This material was covered in part in the 1992 Board Review Course for Clinical Pharmacology sponsored by the American College of Clinical Pharmacology. The format or setting of instruction for this material could include small learning groups composed of 10 to 15 students. When used in combination with other topics prepared in similar formats, this could become a take home course for those preparing to take the Boards in Clinical Pharmacology. Each instructor could select specific publications from the reference list for assigned readings depending upon the material emphasized by the instructor. The questions included at the end of the text could be used as either a closed or an open book quiz to assess student learning. C1 US FDA,DIV CARDIO RENAL,ROCKVILLE,MD. NASA,VISITING SCI PROGRAM,HOUSTON,TX. ROBERT WOOD JOHNSON MED SCH,CAMDEN,NJ. NR 72 TC 15 Z9 15 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQUARE, PHILADELPHIA, PA 19106 SN 0091-2700 J9 J CLIN PHARMACOL JI J. Clin. Pharmacol. PD JUN PY 1995 VL 35 IS 6 BP 573 EP 587 PG 15 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA RD818 UT WOS:A1995RD81800002 PM 7665717 ER PT J AU MADSEN, NK AF MADSEN, NK TI DIVERGENCE PRESERVING DISCRETE SURFACE INTEGRAL METHODS FOR MAXWELLS CURL EQUATIONS USING NONORTHOGONAL UNSTRUCTURED GRIDS SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID FINITE-DIFFERENCE SOLUTION; TIME-DOMAIN; ELECTROMAGNETIC SCATTERING; NUMERICAL-SOLUTION AB Several new discrete surface integral methods for solving Maxwell's equations in the time-domain are presented. These methods, which allow the use of general non-orthogonal mixed-polyhedral unstructured grids, are direct generalizations of the canonical stag gered-grid finite difference method. These methods are conservative in that they locally preserve ''divergence'' or charge, Employing mixed polyhedral cells (hexahedral, tetrahedral, etc.), these methods allow more accurate modeling of non-rectangular structures and objects because the traditional ''stair-stepped'' boundary approximations associated with the orthogonal grid based finite difference methods can be avoided. Numerical results demonstrating the accuracy of these new methods are presented. (C) 1995 Academic Press, Inc. C1 NASA,AMES RES CTR,ADV COMP SCI RES INST,MOFFETT FIELD,CA 94035. RP MADSEN, NK (reprint author), LAWRENCE LIVERMORE NATL LAB,ENGN RES DIV,LIVERMORE,CA 94550, USA. NR 15 TC 61 Z9 61 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN PY 1995 VL 119 IS 1 BP 34 EP 45 DI 10.1006/jcph.1995.1114 PG 12 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QZ750 UT WOS:A1995QZ75000003 ER PT J AU SCOTT, JR ATASSI, HM AF SCOTT, JR ATASSI, HM TI A FINITE-DIFFERENCE, FREQUENCY-DOMAIN NUMERICAL SCHEME FOR THE SOLUTION OF THE GUST RESPONSE PROBLEM SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID UNSTEADY AB A numerical method is developed for solving subsonic flows with convected, three-dimensional vortical waves around lifting airfoils. The first-order method that is presented fully accounts for the distortion effects of the nonuniform mean flow on the convected vorticity, The unsteady velocity is split into a vortical component which is a known function of the upstream flow conditions and the Lagrangian coordinates of the mean flow, and an irrotational field whose potential satisfies a nonconstant-coefficient, inhomogeneous, convective wave equation, Using an elliptic coordinate transformation, the unsteady boundary value problem is solved in the frequency domain on grids which are determined as a function of the Mach number and reduced frequency. Extensive comparisons are made with known solutions to unsteady vortical flow problems, and it is seen that the agreement is in general very good for reduced frequencies ranging from zero to four. (C) 1995 Academic Press. Inc. C1 UNIV NOTRE DAME,NOTRE DAME,IN 46556. RP SCOTT, JR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 19 TC 26 Z9 26 U1 0 U2 3 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUN PY 1995 VL 119 IS 1 BP 75 EP 93 DI 10.1006/jcph.1995.1117 PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QZ750 UT WOS:A1995QZ75000006 ER PT J AU GAWRONSKI, W IH, CHC WANG, SJ AF GAWRONSKI, W IH, CHC WANG, SJ TI ON DYNAMICS AND CONTROL OF MULTILINK FLEXIBLE MANIPULATORS SO JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME LA English DT Article ID MODEL-REDUCTION; ROBOTS; SYSTEMS; LINKS AB This paper presents solutions of dynamics, inverse dynamics, and control problems of multi-link flexible manipulators. In. deriving the manipulator dynamics, flexible deformations are assumed to be small in relation to the link length, angular rates of the links are assumed to be much smaller than their fundamental frequencies, and nonlinear terms (centrifugal and Coriolis forces) in the flexible manipulator model lire assumed to be the same as those in the rigid body model. Flexible displacements are measured with respect to the rigid body configuration, obtained from its rig id body inverse kinematics. As a result, a linear time-varying system is obtained. The inverse dynamics problem consists of determination of joint torques for a given tip trajectory such that joint angles in the flexible configuration are equal to the angles in the rigid body configuration. The manipulator control system consists of the feedforward compensation and feedback control loops. Simulation results of a two-link space crane with a large payload show that the performance of this linearized dynamics and control approach is accurate, and at the same time is robust when subjected to parameter variations during slew operations. RP GAWRONSKI, W (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 24 TC 1 Z9 1 U1 1 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-0434 J9 J DYN SYST-T ASME JI J. Dyn. Syst. Meas. Control-Trans. ASME PD JUN PY 1995 VL 117 IS 2 BP 134 EP 142 DI 10.1115/1.2835173 PG 9 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA RG558 UT WOS:A1995RG55800002 ER PT J AU WEN, LC ROSS, RG AF WEN, LC ROSS, RG TI COMPARISON OF LCC SOLDER JOINT LIFE PREDICTIONS WITH EXPERIMENTAL-DATA SO JOURNAL OF ELECTRONIC PACKAGING LA English DT Article; Proceedings Paper CT Symposium on Mechanics of Surface Mount Assemblies, at the Winter Annual Meeting of ASME CY NOV 06-11, 1994 CL CHICAGO, IL SP Amer Soc Mech Engineers, Electr & Electr Packaging Div AB The ability of solder joint life-prediction algorithms to predict the failure of solder joints due to temperature-cycling induced creep-fatigue has been investigated using representative leadless chip carriers (LCCs) as the test vehicle. Four different algorithms are assessed: the classic Coffin-Manson algorithm, a modified Coffin-Manson algorithm with dependency on peak stress, and two strain-energy based algorithms. JPL's special purpose nonlinear finite element computer program was used to dynamically simulate the solder joint response to the standard NASA temperature cycling environment, which ranges from -55 degrees C to +100 degrees C with a 4-hour period. The computed stress-strain history provided the inputs needed by each of the failure algorithms. To test the accuracy of the analytical predictions, three different sizes of LCCs (68 pins, 28 pins, and 20 pins) were subjected to an experimental test program using the same 4-hour temperature cycle as used in the analytical predictions. The three different sized ceramic packages, each with a 50-mil pitch, provided a range of cyclic strain ranges and solder fillet geometries so as to test the algorithms against realistic electronic packaging variables. The study highlights limitations in the historical Coffin-Manson relationship, and points up possible improvements associated with incorporating a stress modifier into the Coffin-Manson equation. This modification is also somewhat simpler and more accurate than the energy-density based algorithms, which also performed quite well. RP WEN, LC (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 26 TC 10 Z9 10 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1043-7398 J9 J ELECTRON PACKAGING JI J. Electron. Packag. PD JUN PY 1995 VL 117 IS 2 BP 109 EP 115 DI 10.1115/1.2792076 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA RN736 UT WOS:A1995RN73600005 ER PT J AU OGUNJIMI, AO MACGREGOR, S PECHT, MG EVANS, JW AF OGUNJIMI, AO MACGREGOR, S PECHT, MG EVANS, JW TI THE EFFECT OF MANUFACTURING AND DESIGN PROCESS VARIABILITIES ON THE FATIGUE LIFE OF THE HIGH-DENSITY INTERCONNECT VIAS SO JOURNAL OF ELECTRONICS MANUFACTURING LA English DT Article AB Via fatigue failure has been identified(4) as a potential failure mechanism in high density interconnects. This failure mechanism is directly influenced by the stress-strain level at the potential points of failure in the structure and the ductility of the via material. This paper looks at the effect of some manufacturing and design process variables on the fatigue life of the vias. The key variables are the trace or conductor thickness (metallization thickness), the layer or layers of the dielectric around the trace and in the via, the via geometry, wall slope, the ductility coefficient of the conductor material and the strain concentration factor. The metallization thickness is found to have the most dramatic effect on the fatigue life of the via compared to the other design variables. Good via ductility and strain concentration factors improve the fatigue life drastically. C1 NASA,HEADQUARTERS CODE QE,WASHINGTON,DC 20546. RP OGUNJIMI, AO (reprint author), UNIV MARYLAND,CALCE,ELECTR PACKAGING RES CTR,COLLEGE PK,MD 20740, USA. OI Pecht, Michael/0000-0003-1126-8662 NR 10 TC 3 Z9 3 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0960-3131 J9 J ELECTRON MANUF JI J. Electron. Manuf. PD JUN PY 1995 VL 5 IS 2 BP 111 EP 119 DI 10.1142/S0960313195000141 PG 9 WC Engineering, Manufacturing; Engineering, Electrical & Electronic SC Engineering GA RX439 UT WOS:A1995RX43900005 ER PT J AU BENETTI, DD BRILL, RW KRAUL, SA AF BENETTI, DD BRILL, RW KRAUL, SA TI THE STANDARD METABOLIC-RATE OF DOLPHIN FISH SO JOURNAL OF FISH BIOLOGY LA English DT Article DE MAHIMAHI; DORADO; ENERGETICS; PELAGIC FISH; GROWTH ID TUNA KATSUWONUS-PELAMIS; THUNNUS-ALBACARES; CORYPHAENA-HIPPURUS; ACUTE-HYPOXIA; PAGRUS-MAJOR; BODY SIZE; OXYGEN; RESPONSES; GROWTH; GILL AB The standard metabolic rates (SMRs) of 11 (1.395-4.125 kg) dolphin fish (mahimahi or dorado, Coryphaena hippurus) were measured at 25 degrees +/- 0.5 degrees C. Fish were prevented from swimming with neuromuscular blocking agents and force ventilated. Heart rates were determined simultaneously. SMRs (358-726 mg O-2 h(-1)) were several times those of other similarly sized active teleosts such as salmonids, but close to those of tunas. Heart rates (84-161 beats min (-1) ) were also high, but alike those of tunas under similar circumstances. As in tunas, the high SMR of dolphin fish may result from high osmoregulatory costs engendered by their large gill surface areas and/or other adaptations necessary for achieving exceptionally high maximum metabolic rates. C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. UNIV MIAMI,ROSENSTIEL SCH MARINE & ATMOSPHER SCI,DIV MARINE BIOL & FISHERIES,MIAMI,FL 33149. OCEAN INST,HONOLULU,HI 96825. WAIKIKI AQUARIUM,HONOLULU,HI 96815. NR 62 TC 28 Z9 29 U1 3 U2 12 PU ACADEMIC PRESS (LONDON) LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 1995 VL 46 IS 6 BP 987 EP 996 DI 10.1006/jfbi.1995.0094 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA RF153 UT WOS:A1995RF15300007 ER PT J AU SELESNICK, RS CUMMINGS, AC CUMMINGS, JR MEWALDT, RA STONE, EC VONROSENVINGE, TT AF SELESNICK, RS CUMMINGS, AC CUMMINGS, JR MEWALDT, RA STONE, EC VONROSENVINGE, TT TI GEOMAGNETICALLY TRAPPED ANOMALOUS COSMIC-RAYS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR; COMPONENT; MAGNETOSPHERE; SPECTRA; OXYGEN; STATES; IONS AB Since its launch in July 1992, the polar-orbiting satellite SAMPEX has been collecting data on geomagnetically trapped heavy ions, predominantly O. N, and Ne, at energies greater than or similar to 15 MeV/nucleon and in a narrow L shell range near L = 2. Their location, elemental composition, energy spectra, pitch angle distribution, and time variations all support the theory that these particles originated as singly ionized interplanetary anomalous cosmic rays that were stripped of electrons in the Earth's upper atmosphere and subsequently, trapped, The O are observed primarily at pitch angles outside the atmospheric loss cones, consistent with a trapped population, and their distribution there is nearly isotropic. The abundances relative to O of the N, possibly Ne, and especially C are lower than the corresponding interplanetary values, which may be indicative of the trapping efficiencies. The distributions of trapped N, O, and Ne in energy and L shell suggest that most of the ions observed at the SAMPEX altitude of similar to 600 km are not fully stripped when initially trapped. A comparison of the trapped intensity with the much lower interplanetary intensity of anomalous cosmic rays provides model-dependent estimates of the product of the trapping probability and the average trapped particle lifetime against ionization losse's in the residual atmosphere for particles that mirror near the SAMPEX altitude. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. CALTECH,PASADENA,CA 91125. NR 36 TC 44 Z9 44 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1995 VL 100 IS A6 BP 9503 EP 9518 DI 10.1029/94JA03140 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC077 UT WOS:A1995RC07700005 ER PT J AU GUITER, SM GOMBOSI, TI RASMUSSEN, CE AF GUITER, SM GOMBOSI, TI RASMUSSEN, CE TI 2-STREAM MODELING OF PLASMASPHERIC REFILLING SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERHEMISPHERIC PLASMA-FLOW; ION TEMPERATURE ANISOTROPY; EARTHS MAGNETIC EQUATOR; TRANSPORT AB Plasmaspheric refilling on an L = 4, flux tube was studied by using a time-dependent, hydrodynamic plasmaspheric flow model in which the ion streams from the two hemispheres are treated as distinct fluids. In the model the continuity, momentum, and energy equations of a two-ion (O+ and H+), quasi-neutral, currentless plasma are solved along a closed geomagnetic field line; diffusive equilibrium is not assumed. Collisions between all stream pairs and with neutral species are included. The model includes a corotating, tilted dipole magnetic field and neutral winds. Ionospheric sources and sinks are accounted for in a self-consistent manner. Electrons are assumed to be heated by photoelectrons. The model flux tube extends from 200-km altitude in one hemisphere to 200-km altitude in the other hemisphere. Initially, the upwelling streams pass through each other practically unimpeded. When the streams approach the boundary in the conjugate ionosphere, a shock develops there, which moves upward and dissipates slowly; at about the same time a reverse shock develops in the hemisphere of origin, which moves upward. After about 1 hour, large shocks develop in each stream near the equator; these shocks move toward the equator and downward after crossing the equator. However, these shocks are probably artificial, because counterstreaming flows occur in each H+ fiuid, which the model can only handle by creating shocks. C1 UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. RI Gombosi, Tamas/G-4238-2011 OI Gombosi, Tamas/0000-0001-9360-4951 NR 25 TC 10 Z9 10 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 JUN 1 PY 1995 VL 100 IS A6 BP 9519 EP 9526 DI 10.1029/95JA00081 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC077 UT WOS:A1995RC07700006 ER PT J AU ZHANG, X COMFORT, RH GALLAGHER, DL GREEN, JL MUSIELAK, ZE MOORE, TE AF ZHANG, X COMFORT, RH GALLAGHER, DL GREEN, JL MUSIELAK, ZE MOORE, TE TI MAGNETOSPHERIC FILTER EFFECT FOR PC-3 ALFVEN MODE WAVES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PULSATIONS; PLASMA AB We present a ray-tracing study of the propagation of Pc 3 Alfven mode waves originating at the dayside magnetopause, This study reveals interesting features of a magnetospheric filter effect for these waves. Pc 3 Alfven mode waves cannot penetrate to low Earth altitudes unless the wave frequency is below approximately 30 mHz. Configurations of the dispersion curves and the refractive index show that the gyroresonance and pseudo-cutoff introduced by the heavy ion O+ block the waves. When the O+ concentration is removed from the plasma composition, the barriers caused by the O+ no longer exist, and waves with much higher frequencies than 30 mHz can penetrate to low altitudes. The result that the 30-mHz or lower frequency Alfven waves can be guided to low altitudes agrees with ground-based power spectrum observations at high latitudes. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NASA,GODDARD SPACE FLIGHT CTR,NATL SPACE SCI DATA CTR,GREENBELT,MD 20771. RP ZHANG, X (reprint author), UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,HUNTSVILLE,AL 35899, USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 26 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1995 VL 100 IS A6 BP 9585 EP 9590 DI 10.1029/95JA00276 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC077 UT WOS:A1995RC07700014 ER PT J AU FOK, MC MOORE, TE KOZYRA, JU HO, GC HAMILTON, DC AF FOK, MC MOORE, TE KOZYRA, JU HO, GC HAMILTON, DC TI 3-DIMENSIONAL RING CURRENT DECAY MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EQUATORIAL MAGNETOSPHERE; GEOMAGNETIC STORM; ION COMPOSITION; PLASMASPHERE; PARTICLES AB This work is an extension of a previous ring current decay mb;del. In the previous work, a two-dimensional kinetic model was constructed to study the temporal variations of the equatorially mirroring ring current ions, considering charge exchange and Coulomb drag losses along drift paths in a magnetic dipole field. In this work, particles with arbitrary pitch angle-are considered. By bounce averaging the kinetic equation of the phase space density, information along magnetic field lines can be inferred from the equator. The three-dimensional model is used to simulate the recovery phase of a model great magnetic storm, similar to that which occurred in early February 1986. The initial distribution of ring current ions (at the minimum Dst) is extrapolated to all local times from AMPTE/CCE, spacecraft observations on the dawnside and duskside of the inner magnetosphere spanning the L value range L = 2.25 to 6.75. Observations by AMPTE/CCE of ring current distributions over subsequent orbits during the storm recovery phase are compared to model outputs. in general, the calculated ion fluxes are consistent with observations, except for H+ fluxes at tens of keV, which are always overestimated. A newly invented visualization idea, designated as a chromogram, is used to display the spatial and energy dependence of the ring current ion differential flux. Important features of storm time ring current, such as day-night asymmetry during injection and drift hole on the dayside at low energies (<10 keV), are manifested in the chromogram representation. The pitch angle distribution is well fit by the function, j(0)(1 + Ay(n)), where y is sine of the equatorial pitch angle. The evolution of the index n is a combined effect of charge exchange loss and particle drift. At low energies (<30 keV), both drift dispersion and charge exchange are important in determining n. C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. RP FOK, MC (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES83,HUNTSVILLE,AL 35812, USA. RI Moore, Thomas/D-4675-2012; Fok, Mei-Ching/D-1626-2012; Ho, George/G-3650-2015 OI Moore, Thomas/0000-0002-3150-1137; Ho, George/0000-0003-1093-2066 NR 40 TC 109 Z9 111 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1995 VL 100 IS A6 BP 9619 EP 9632 DI 10.1029/94JA03029 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC077 UT WOS:A1995RC07700017 ER PT J AU HERWITZ, SR SLYE, RE AF HERWITZ, SR SLYE, RE TI 3-DIMENSIONAL MODELING OF CANOPY TREE INTERCEPTION OF WIND-DRIVEN RAINFALL SO JOURNAL OF HYDROLOGY LA English DT Article ID NEW-SOUTH-WALES; FOREST CANOPY; EUCALYPTUS-VIMINALIS; TURBULENCE STRUCTURE; TROPICAL RAINFOREST; DECIDUOUS FOREST; PINUS-RADIATA; SITKA SPRUCE; STEMFLOW; THROUGHFALL AB Field measurement of interception loss from rainforest vegetation in the cyclone-prone tropics is complicated by high wind speeds that cause incident rainfall to be inclined from vertical fall paths. Given the characteristic roughness of tropical rainforest canopies, we hypothesized that the more prominent canopy tree crowns create lateral rainshadows and intercept greater volumes of rainwater per unit projected crown area than less prominent neighboring canopy trees under inclined rainfall conditions. This hypothesis was tested by: (1) modeling the three-dimensional (3-D) geometry of a tropical rainforest canopy surface in northeast Queensland, Australia, using photogrammetrically derived crown elevation data; (2) computing the inclination angles and azimuths of wind-driven rainfall for raindays on which net rainfall was measured from selected canopy trees; (3) creating and applying a ray-tracing program to the 3-D canopy model to quantify lateral rainshadows and the effective rainfall-intercepting crown areas of the selected canopy trees; (4) calculating the C-e/C index (effective rainfall-intercepting crown area/projected crown area ratio) of each tree; (5) analyzing the relationship between the C-e/C index values and the measured net rainfall totals after correcting for differences in the trees' interception storage capacities. A significant correlation (P < 0.05) was found for more than 80% of the raindays examined with rainfall inclination angles of more than 19 degrees from a vertical fall path. These results suggest that the variation in net rainfall totals among neighboring canopy trees may be explained in part by the differential interception of inclined rainfall. Interception loss is generally measured as the difference between gross rainfall measured in the open and net rainfall reaching the forest floor. We conclude that more meaningful measures of interception loss could be obtained by accounting for differences in gross rainfall intercepted by canopy trees sampled for net rainfall. C1 CLARK UNIV,DEPT BIOL,WORCESTER,MA 01610. NASA,AMES RES CTR,ECOSYST SCI & TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP HERWITZ, SR (reprint author), CLARK UNIV,GRAD SCH GEOG,WORCESTER,MA 01610, USA. NR 60 TC 55 Z9 58 U1 2 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD JUN PY 1995 VL 168 IS 1-4 BP 205 EP 226 DI 10.1016/0022-1694(94)02643-P PG 22 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA QY989 UT WOS:A1995QY98900011 ER PT J AU SILCOX, RJ FULLER, CR BURDISSO, RA AF SILCOX, RJ FULLER, CR BURDISSO, RA TI CONCEPTS ON AN INTEGRATED DESIGN APPROACH TO THE ACTIVE CONTROL OF STRUCTURALLY RADIATED NOISE (ASAC) SO JOURNAL OF MECHANICAL DESIGN LA English DT Article AB This work describes a range of issues relating to the implementation of active control for noise and vibration problems. It is important in the commercialization of this technology to consider these and many other factors relating to design of these systems. Many of the concepts required for efficient implementation haw not been considered and it is important to begin giving design consideration to these aspects. A design technique based upon the eigenbehavior of feedforward controlled systems is developed and applied to control radiation from structures. Integration of the control system with the physical system dynamics allows the eigenproperties to be defined to meet a prescribed design criteria. Here the technique is demonstrated to implement a structural system that inefficiently couples vibration energy to acoustic energy. In addition, an approach to integrate ''knowledge'' about actuator configurations into art active control system that reduces spillover effects into structural vibrations is demonstrated. This approach has the advantages that no additional hardware is required while also reducing the order of the control system in terms of degrees of freedom. Finally, some design trade-offs between the passive material properties of an active trim panel and control system performance are examined. Improved performance can be attained but at the cost of additional weight. RP SILCOX, RJ (reprint author), NASA,LANGLEY RES CTR,STRUCT ACOUST BRANCH,HAMPTON,VA 23681, USA. NR 0 TC 2 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 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD JUN PY 1995 VL 117 SI B BP 261 EP 270 PG 10 WC Engineering, Mechanical SC Engineering GA RK663 UT WOS:A1995RK66300034 ER PT J AU KUKKONEN, CA AF KUKKONEN, CA TI NASA high performance computing, communications, image processing, and data visualization-potential applications to medicine SO JOURNAL OF MEDICAL SYSTEMS LA English DT Proceedings Paper CT 2nd NASA/USUHS International Conference on Telemedicine for Remote Health Care and Disaster Response CY SEP 06-10, 1994 CL BETHESDA, MD SP NASA, UNIFORMED SERV UNIV HLTH SCI RP KUKKONEN, CA (reprint author), CALTECH,NASA,JET PROPULS LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91125, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0148-5598 J9 J MED SYST JI J. Med. Syst. PD JUN PY 1995 VL 19 IS 3 BP 263 EP 273 DI 10.1007/BF02257177 PG 11 WC Health Care Sciences & Services; Medical Informatics SC Health Care Sciences & Services; Medical Informatics GA QY386 UT WOS:A1995QY38600004 PM 7643022 ER PT J AU STOWE, RP KOENIG, DW MISHRA, SK PIERSON, DL AF STOWE, RP KOENIG, DW MISHRA, SK PIERSON, DL TI NONDESTRUCTIVE AND CONTINUOUS SPECTROPHOTOMETRIC MEASUREMENT OF CELL RESPIRATION USING A TETRAZOLIUM-FORMAZAN MICROEMULSION SO JOURNAL OF MICROBIOLOGICAL METHODS LA English DT Article DE TETRAZOLIUM REDUCTION; TRITON X-100; MTT-BIOASSAY; CELL RESPIRATION ID RAPID COLORIMETRIC ASSAY; RESPIRING BACTERIA; ESCHERICHIA-COLI; TRITON X-100; CHEMOSENSITIVITY; SOLUBILIZATION; GROWTH; DETERGENTS; REDUCTION; SURVIVAL AB Triton X-100 was incorporated into a tetrazolium dye reduction assay using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT). Triton X-100 combines with the insoluble formazan product to form a homogeneous dispersion, or microemulsion, which allows reliable spectrophotometric measurement. The combination of this nonionic detergent and dye allows respiration to be measured nondestructively and thus continuously. The assay combines MTT with phenazine methosulfate, the appropriate cell growth substrate, and Triton X-100. Addition of the cells results in the conversion of MTT to the colored formazan. This assay was tested using cultures of bacteria and yeast. Various factors such as MTT concentration, cell number, and concentration of Triton X-100 were optimized. A comparison was then made between viable cell counts obtained by the plate count method and MTT-formazan production measured spectrophotometrically. A linear relationship was demonstrated between cell number and MTT-formazan production. The advantage of this method is that the stabilized MTT-formazan microemulsion eliminates the need for organic solvent extraction steps and also inhibits further cellular reduction of the formazan to its colorless end-product. Because the cells are not destroyed, as is the case with other tetrazolium methods using organic solvents, cell viability can be assessed rapidly. Some bacteria can be assayed in only 30 min as compared to 6-12 h for other traditional tetrazolium methods. C1 NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,HOUSTON,TX 77058. RP STOWE, RP (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MICROBIOL LAB,1290 HERCULES AVE,SUITE 120,HOUSTON,TX 77058, USA. NR 32 TC 24 Z9 27 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7012 J9 J MICROBIOL METH JI J. Microbiol. Methods PD JUN PY 1995 VL 22 IS 3 BP 283 EP 292 DI 10.1016/0167-7012(95)00009-A PG 10 WC Biochemical Research Methods; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA RD813 UT WOS:A1995RD81300007 ER PT J AU TSOU, P AF TSOU, P TI SILICA AEROGEL CAPTURES COSMIC DUST INTACT SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 4th International Symposium on Aerogels (ISA-4) CY SEP 19-21, 1994 CL BERKELEY, CA AB The mesostructure of silica aerogel resembles strings of pearls, ranging in size from 10 to 100 Angstrom. This fine mesostructure transmits nearly 90% of incident light in the visible, while providing sufficiently gentle dissipation of the kinetic energy of hypervelocity cosmic dust particles to permit their intact capture. In 1987, silica aerogel was introduced as a capture medium to take advantage of its low density, fine mesostructure and, most importantly, its transparency, allowing optical location of captured micron sized particles. Without this feature, locating such captured particles in an opaque medium, e.g., polymer foams, is nearly impossible. The capture of hypervelocity particles has been extensively simulated in the laboratory. At the time of this symposium, more than 2.4 m(2) of 20 mg/ml silica aerogel will have been flown on Space Shuttle (STS-47, STS-57, STS-60, STS-64 and STS-68). Demonstration of capturing hypervelocity particles ushers in a new, simple avenue to science in capturing intact cosmic dust from space. Since our introduction of aerogel for intact capture of cosmic dust, many useful features unique to aerogel have been identified. RP TSOU, P (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 18 TC 124 Z9 131 U1 3 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD JUN PY 1995 VL 186 BP 415 EP 427 DI 10.1016/0022-3093(95)00065-8 PG 13 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA RE654 UT WOS:A1995RE65400058 ER PT J AU HUDGINS, DM ALLAMANDOLA, LJ AF HUDGINS, DM ALLAMANDOLA, LJ TI INFRARED-SPECTROSCOPY OF MATRIX-ISOLATED POLYCYCLIC AROMATIC HYDROCARBON CATIONS .3. THE POLYACENES ANTHRACENE, TETRACENE, AND PENTACENE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID VIBRONIC ABSORPTION-SPECTRA; CONDENSED AROMATICS; EMISSION FEATURES; SOLID ARGON; NAPHTHALENE; PRESSURE AB Gaseous, ionized polycyclic aromatic hydrocarbons (PAHs) are thought to be responsible for a very common family of interstellar infrared emission bands. Unfortunately, very little infrared spectroscopic data are available on ionized PAHs. Here we present the near- and mid-infrared spectra of the polyacene cations anthracene, tetracene, and pentacene. We also report the vibrational frequencies and relative intensities of the pentacene anion. The cation bands corresponding to the CC modes are typically about 10-20 times more intense than those of the CH out-of-plane bending vibrations. For the cations the CC stretching and CH in-plane bending modes give rise to bands which are an order of magnitude stronger than for the neutral species, and the CH out-of-plane bends produce bands which are 3-20 times weaker than in the neutral species. This behavior is similar to that found for most other PAH cations. The most intense PAH cation bands fall within the envelopes of the most intense interstellar features. The strongest absorptions in the polyacenes anthracene, tetracene, and pentacene tend to group around 1400 cm(-1) (between about 1340 and 1500 cm(-1)) and near 1180 cm(-1), regions of only moderate interstellar emission. These very strong polyacene bands tend to fall in gaps in the spectra of the other PAH cations studied to date suggesting that while PAHs with polyacene structures may contribute to specific regions of the interstellar emission spectra, they are not dominant members of the interstellar PAH family. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 32 TC 107 Z9 107 U1 2 U2 31 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 1 PY 1995 VL 99 IS 22 BP 8978 EP 8986 DI 10.1021/j100022a007 PG 9 WC Chemistry, Physical SC Chemistry GA RB252 UT WOS:A1995RB25200007 PM 11538316 ER PT J AU RICCA, A BAUSCHLICHER, CW AF RICCA, A BAUSCHLICHER, CW TI SUCCESSIVE H2O BINDING-ENERGIES FOR FE(H2O)(N)(+) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID METAL POSITIVE-IONS; 2 WATER-MOLECULES; N = 1-4; 1ST; ATOMS AB The successive H2O binding energies, computed using density functional theory (DFT), are in good agreement with experiment. The bonding is electrostatic (charge-dipole) in origin for ah systems. The structures are therefore determined mostly by metal-ligand and ligand-ligand repulsion. The computed structure for FeH2O+ is C-2 upsilon, where sp hybridization is important in reducing the Fe-H2O repulsion. Fe(H2O)(2)(+) has D-2d symmetry where sd(sigma) hybridization is the primary factor leading to the Linear O-Fe-O geometry. The bonding in Fe(H2O)(3)(+) and Fe(H2O)(4)(+) is very complex because ligand-ligand and metal-ligand repulsion, both for the in-plane and out-of-plane water lone-pair orbitals, are important. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 24 TC 81 Z9 83 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD JUN 1 PY 1995 VL 99 IS 22 BP 9003 EP 9007 DI 10.1021/j100022a010 PG 5 WC Chemistry, Physical SC Chemistry GA RB252 UT WOS:A1995RB25200010 ER PT J AU BENNER, DC RINSLAND, CP DEVI, VM SMITH, MAH ATKINS, D AF BENNER, DC RINSLAND, CP DEVI, VM SMITH, MAH ATKINS, D TI A MULTISPECTRUM NONLINEAR LEAST-SQUARES FITTING TECHNIQUE SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID LORENTZ-BROADENING COEFFICIENTS; LINE-SHIFT COEFFICIENTS; ABSOLUTE INTENSITY MEASUREMENTS; INFRARED SOLAR SPECTRA; CARBON-DIOXIDE BANDS; TUNABLE DIODE-LASER; 5.2 MU-M; METHANE LINES; HALF-WIDTHS; NU-2 BANDS AB An extension of the nonlinear least squares spectrum fitting technique has been developed for the simultaneous fitting of multiple spectra. This procedure's smaller number of fitted parameters as compared to fitting one spectrum at a time improves the determination of spectroscopic parameters. A more reliable evaluation of the errors associated with the solution is possible. Correlations among fitted parameters may preclude their determination from a single spectrum fit. If the correlations differ from spectrum to spectrum, however, separation of these parameters is often possible when including the spectra in one solution. Overfitting is also avoided when combining spectra with sufficiently different experimental physical conditions. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP BENNER, DC (reprint author), COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187, USA. NR 46 TC 186 Z9 185 U1 4 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD JUN PY 1995 VL 53 IS 6 BP 705 EP 721 DI 10.1016/0022-4073(95)00015-D PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA RF752 UT WOS:A1995RF75200012 ER PT J AU ZUCKERWAR, AJ CUOMO, FW NGUYEN, TD RIZZI, SA CLEVENSON, SA AF ZUCKERWAR, AJ CUOMO, FW NGUYEN, TD RIZZI, SA CLEVENSON, SA TI HIGH-TEMPERATURE FIBEROPTIC LEVER MICROPHONE SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article C1 FW CUOMO CONSULTING SERV, E PROVIDENCE, RI 02914 USA. OLD DOMINION UNIV, NORFOLK, VA 23508 USA. RP NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NR 15 TC 6 Z9 6 U1 0 U2 0 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 EI 1520-8524 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1995 VL 97 IS 6 BP 3605 EP 3616 DI 10.1121/1.412947 PG 12 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA RD453 UT WOS:A1995RD45300015 ER PT J AU CONSTANTINE, W PEZESHKI, C BAMBERGER, R MOSHER, M AF CONSTANTINE, W PEZESHKI, C BAMBERGER, R MOSHER, M TI DISCRETE WAVELET ANALYSIS OF BLADE-VORTEX INTERACTION NOISE SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID FILTERS C1 WASHINGTON STATE UNIV, SCH ELECT ENGN & COMP SCI, PULLMAN, WA 99164 USA. NASA, AMES RES CTR, ROTORCRAFT AEROMECH BRANCH, MOFFETT FIELD, CA 94035 USA. RP CONSTANTINE, W (reprint author), WASHINGTON STATE UNIV, DEPT MECH & MAT ENGN, PULLMAN, WA 99164 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1995 VL 97 IS 6 BP 3688 EP 3693 DI 10.1121/1.413064 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA RD453 UT WOS:A1995RD45300024 ER PT J AU TAO, WK SCALA, JR FERRIER, B SIMPSON, J AF TAO, WK SCALA, JR FERRIER, B SIMPSON, J TI THE EFFECT OF MELTING PROCESSES ON THE DEVELOPMENT OF A TROPICAL AND A MIDLATITUDE SQUALL LINE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID HIGH-PLAINS CUMULONIMBI; LONGWAVE RADIATION; MOMENTUM FLUX; MESOSCALE; PRECIPITATION; DOWNDRAFTS; DYNAMICS; ORGANIZATION; SENSITIVITY; TRANSPORT AB Several sensitivity tests are performed to assess the effect of melting processes on the development of a midlatitude continental squall line and a tropical oceanic squall line. It is found that melting processes play an important role in the structure of a midlatitude continental squall system. For the maritime tropical case, squall development is not as sensitive to the presence of melting, due to the dominance of warm rain processes. Melting processes exert an influence on midlatitude cloud system development through the conversion of ice particles to rain. The simulated convective system was found to be much weaker in the absence of evaporative cooling by rain. For a given vertical shear of horizontal wind, cooling by evaporation in the convective region was found to be essential for maintaining a long-lived cloud system. Diabatic cooling by melting played only a secondary role in this respect. In the absence of melting processes, the simulated midlatitude squall system acquired the characteristics of unicell-type (erect and steady) convection rather than the observed multicellular (upshear tilt) structure. This suggests that the diabatic cooling by melting can have significant impact on the structure (dynamics) of a simulated midlatitude squall system. In addition, results from air parcel trajectory analyses indicate that jump-type downdrafts that originate either from the convective region or from above the melting level in the stratiform region are not simulated for convection that develops in the absence of melting. The horizontal momentum transport associated with the midlatitude squall system simulations were quite different in the presence and absence of melting. Significant horizontal momentum transport by convection was not observed in the absence of melting. However, an upper-level jet was simulated in the case where melting processes were active. It is also found that the horizontal perturbed pressure gradient force is comparable in magnitude yet almost always opposite in sign to the vertical transport effect by clouds. C1 SCI SYST & APPLICAT INC,LANHAM,MD. RP TAO, WK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,MESOSCALE DYNAM & PRECIPITAT BRANCH,CODE 912,GREENBELT,MD 20771, USA. NR 32 TC 41 Z9 41 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1995 VL 52 IS 11 BP 1934 EP 1948 DI 10.1175/1520-0469(1995)052<1934:TEOMPO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RC286 UT WOS:A1995RC28600007 ER PT J AU KEPPENNE, CL INGERSOLL, AP AF KEPPENNE, CL INGERSOLL, AP TI HIGH-FREQUENCY OROGRAPHICALLY FORCED VARIABILITY IN A SINGLE-LAYER MODEL OF THE MARTIAN ATMOSPHERE SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SOUTHERN OSCILLATION CYCLE; GENERAL-CIRCULATION MODEL; STATISTICAL-MODELS; DYNAMICS; EQUATION AB A shallow water model with realistic topography and idealized zonal wind forcing is used to investigate orographically forced modes in the Martian atmosphere. Locally, the model produces barotropic modes with periods within the broad range of periods observed at the sites of Viking Lander I and II (VL1 and VL2) during the fall and spring seasons. Its variability at those sites is dominated by an oscillation of 3 Martian solar days (sols) in the region of VL1 and by a 6-sol oscillation in that of VL2. These oscillations are forced by the zonal asymmetries of the Martian mountain field. Their robustness with respect to changes of the fundamental model parameters is examined. Since the exhibited periods occur for a barotropic forcing field that is highly idealized, it is difficult to say whether they have much to do with the real Mars, but their resemblance to some of-the periodicities present in the observed Martian climatology deserves further investigation. The spatial variability associated with the orographically forced oscillations is studied by means of extended empirical orthogonal function (EEOF) analysis. The 3-sol VL1 oscillation corresponds to a tropical, eastward traveling, zonal wavenumber one pattern. The 6-sol VL2 oscillation is characterized by two midlatitude, eastward traveling, mixed zonal wavenumber one and two and zonal wavenumber three and four patterns, with respective periods near 6.1 and 5.5 sols. The corresponding phase speeds are in agreement with some of the conclusions drawn from the lander observations. A linear stability analysis of the zonally asymmetric climatology reveals that the two most unstable modes are associated with periods near 3 and 6 sols; with the corresponding eigenvectors showing patterns consistent with the results of the EEOF analyses. C1 CALTECH,DIV GEOL & PLANETARY SCI,PASADENA,CA 91125. RP KEPPENNE, CL (reprint author), CALTECH,JET PROP LAB,MAIL STOP 238-332,4800 OAK GROVE DR,PASADENA,CA 91100, USA. NR 38 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1995 VL 52 IS 11 BP 1949 EP 1958 DI 10.1175/1520-0469(1995)052<1949:HFOFVI>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RC286 UT WOS:A1995RC28600008 ER PT J AU CHAO, WC AF CHAO, WC TI A CRITIQUE OF WAVE-CISK AS AN EXPLANATION FOR THE 40-50 DAY TROPICAL INTRASEASONAL OSCILLATION SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID EVAPORATION-WIND FEEDBACK; EQUATORIAL BETA-PLANE; MOIST KELVIN WAVE; WESTERN PACIFIC; SUPER CLUSTERS; SIMPLE-MODEL; ATMOSPHERE; ORIGIN; DYNAMICS; CIRCULATION AB The two major difficulties, i.e., the excessive speed and the smallest preferred scale, encountered by wave-CISK as an explanation for the 40-50 day tropical intraseasonal oscillation (or the Madden-Julian oscillation, MJO), as demonstrated in many studies, are examined. In addition, wave-CISK is contrasted with a more promising framework for interpreting MJO recently proposed by Chao and Lin. The central cause for the two difficulties can be attributed to the convective heating formulation used. Also, depending on how one defines it, the wave-CISK concept as the foundation for interpreting MJO is at best inadequate and at worst erroneous. RP CHAO, WC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 43 TC 15 Z9 18 U1 0 U2 5 PU METEOROLOGICAL SOC JPN PI TOKYO PA C/O JPN METEOROL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO JAPAN SN 0026-1165 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD JUN PY 1995 VL 73 IS 3 BP 677 EP 684 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RL313 UT WOS:A1995RL31300001 ER PT J AU MCKECHNIE, T KROTZ, P LIAW, YK POORMAN, RM ZIMMERMAN, F HOLMES, R AF MCKECHNIE, T KROTZ, P LIAW, YK POORMAN, RM ZIMMERMAN, F HOLMES, R TI SYMPOSIUM ON SPRAY FORMING, ANAHEIM, CA, JUNE 1993 - ABSTRACTS SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Article C1 ROCKWELL INT CORP,DIV ROCKETDYNE,MSFC TECHNOL SUPPORT,SE DIST OPERAT,HUNTSVILLE,AL 35806. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NR 0 TC 0 Z9 0 U1 1 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD JUN PY 1995 VL 4 IS 2 BP 143 EP 146 DI 10.1007/BF02646103 PG 4 WC Materials Science, Coatings & Films SC Materials Science GA TA107 UT WOS:A1995TA10700006 ER PT J AU MEYERS, JF AF MEYERS, JF TI DEVELOPMENT OF DOPPLER GLOBAL VELOCIMETRY AS A FLOW DIAGNOSTICS TOOL SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article AB The development of Doppler global velocimetry is described from its inception to its use as a flow diagnostics tool. Its evolution is traced from an elementary one-component laboratory prototype, to a full three-component configuration operating in a wind tunnel at focal distances exceeding 15 m. As part of the developmental process, several wind tunnel flow field investigations were conducted. These included supersonic flow measurements about an oblique shock, subsonic and supersonic measurements of the vortex flow above a delta wing and three-component measurements of a high-speed jet. RP NASA, LANGLEY RES CTR, MAIL STOP 235A, HAMPTON, VA 23681 USA. NR 23 TC 50 Z9 52 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD JUN PY 1995 VL 6 IS 6 BP 769 EP 783 DI 10.1088/0957-0233/6/6/014 PG 15 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA RD758 UT WOS:A1995RD75800015 ER PT J AU RULISON, AJ RHIM, WK AF RULISON, AJ RHIM, WK TI CONSTANT-PRESSURE SPECIFIC-HEAT TO HEMISPHERICAL TOTAL EMISSIVITY RATIO FOR UNDERCOOLED LIQUID NICKEL, ZIRCONIUM, AND SILICON SO METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE LA English DT Article ID TEMPERATURE AB Radiative cooling curves of nickel, zirconium, and silicon melts that were obtained using the high-temperature, high-vacuum electrostatic levitator (HTHVESL) have been analyzed to determine the ratio between the constant-pressure specific heat and the hemispherical total emissivity, c(p)(T)/epsilon(T)(T). This ratio determined over a wide liquid temperature range for each material allows us to determine c(p)(T) if epsilon(T)(T) is known or vice versa. Following the recipe, the hemispherical total emissivities for each sample at its melting temperature, epsilon(T)(T-m), have been determined using c(p)(T-m) values available in the literature. They are 0.15, 0.29, and 0.17, for Ni, Zr, and Si, respectively. C1 JET PROP LAB, TECH STAFF, PASADENA, CA 91109 USA. RP RULISON, AJ (reprint author), JOHNS HOPKINS UNIV, DEPT CHEM ENGN, BALTIMORE, MD 21218 USA. NR 10 TC 30 Z9 30 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5615 J9 METALL MATER TRANS B JI Metall. Mater. Trans. B-Proc. Metall. Mater. Proc. Sci. PD JUN PY 1995 VL 26 IS 3 BP 503 EP 508 DI 10.1007/BF02653866 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA RA343 UT WOS:A1995RA34300009 ER PT J AU CHARNLEY, SB TIELENS, AGGM KRESS, ME AF CHARNLEY, SB TIELENS, AGGM KRESS, ME TI ORGANIC-MOLECULES IN OXYGEN-RICH CIRCUMSTELLAR ENVELOPES - METHANOL AND HYDROCARBONS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Letter DE MOLECULAR PROCESSES; CIRCUMSTELLAR MATTER; STARS, LATE-TYPE ID CARBON-BEARING MOLECULES; IRC + 10216; 1ST DETECTION; STARS; PHOTODISSOCIATION; FORMALDEHYDE; OUTFLOWS; EMISSION AB The existence of anomalously high abundances of gaseous CH4 has been invoked to explain the unexpectedly high abundances of the carbon-bearing molecules HCN and H2CO in the outflows from O-rich red giants. We have modelled the chemistry that proceeds in the outer envelope when CH4 is injected from the inner envelope. We find that photolysis by the interstellar radiation field drives an ion-neutral chemistry which produces several organic molecules. The calculated abundances of CH3OH, C2H and C-2 can be comparable to those calculated for H2CO and HCN. Species such as C2H4, C2H2 and CH3CN can also be abundant. A search for CH3OH and C2H in several O-rich outflows known to exhibit strong HCN emission is needed. As it derives entirely from the CH4 photochain, is insensitive to the envelope temperature distribution, and has accessible transitions at millimetre wavelengths, the detection of the C2H radical would provide further indirect support for the presence of the hypothesized methane. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RENSSELAER POLYTECH INST,DEPT PHYS,TROY,NY 12180. RP CHARNLEY, SB (reprint author), UNIV CALIF BERKELEY,DEPT ASTRON,CAMPBELL HALL,BERKELEY,CA 94720, USA. RI Charnley, Steven/C-9538-2012 NR 29 TC 18 Z9 18 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 1 PY 1995 VL 274 IS 3 BP L53 EP L57 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RB187 UT WOS:A1995RB18700002 ER PT J AU SPENCER, RW LAPENTA, WM ROBERTSON, FR AF SPENCER, RW LAPENTA, WM ROBERTSON, FR TI VORTICITY AND VERTICAL MOTIONS DIAGNOSED FROM SATELLITE DEEP-LAYER TEMPERATURES SO MONTHLY WEATHER REVIEW LA English DT Article ID RADIOSONDE VALIDATION; OMEGA-EQUATION; ANOMALIES; RESOLUTION; PRECISION; CYCLONES AB Spatial fields of satellite-measured deep-layer temperatures are examined in the context of quasigeostrophic theory. it is found that midtropospheric geostrophic vorticity and quasigeostrophic vertical motions can be diagnosed from microwave temperature measurements of only two deep layers. The lower- (1000-400 hPa) and upper- (400-50 hPa) layer temperatures are estimated from limb-corrected TIROS-N Microwave Sounding Units (MSU)channel 2 and 3 data, spatial fields of which can be used to estimate the midtropospheric thermal wind and geostrophic vorticity fields. Together with Trenberth's simplification of the quasigeostrophic omega equation, these two quantities can be then used to estimate the geostrophic vorticity advection by the thermal wind, which is related to the quasigeostrophic vertical velocity in the midtroposphere. Critical to the technique is the observation that geostrophic vorticity fields calculated from the channel 3 temperature features are very similar to those calculated from traditional, ''bottom-up'' integrated height fields From radiosonde data. This suggests a lack of cyclone-scale height features near the top of the channel 3 weighting function, making the channel 3 cyclone-scale ''thickness'' features approximately the same as height features near the bottom of the weighting function. Thus, the MSU data provide observational validation of the LID (level of insignificant dynamics) assumption of Hirshberg and Fritsch. RP SPENCER, RW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,DIV EARTH SYST SCI,ES43,HUNTSVILLE,AL 35812, USA. NR 21 TC 6 Z9 6 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUN PY 1995 VL 123 IS 6 BP 1800 EP 1810 DI 10.1175/1520-0493(1995)123<1800:VAVMDF>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ935 UT WOS:A1995QZ93500011 ER PT J AU AVERSA, F BARBIELLINI, G BOEZIO, M BRAVAR, U COLAVITA, A FRATNIK, F SCHIAVON, P VACCHI, A ZAMPA, N BIDOLI, V CANDUSSO, M CASOLINO, M DEPASCALE, MP MORSELLI, A PICOZZA, P SPARVOLI, R BOCCIOLINI, M CELLETTI, F FINETTI, N GRANDI, M PAPINI, P PEREGO, A PICCARDI, S SPILLANTINI, P BASINI, G BRANCACCIO, FM MAZZENGA, G RICCI, M BELLOTTI, R CAFAGNA, F CASTELLANO, M CIRCELLA, M DEMARZO, C DECATALDO, G GIGLIETTO, N MARANGELLI, B RAINO, A SPINELLI, P BRUNETTI, MT CODINO, A GRIMANI, C MENICHELLI, M MIOZZA, M BRONZINI, F GOLDEN, RL STOCHAJ, SJ STEPHENS, SA MITCHELL, JW ORMES, JF STREITMATTER, RE HOF, M MENN, W SIMON, M AF AVERSA, F BARBIELLINI, G BOEZIO, M BRAVAR, U COLAVITA, A FRATNIK, F SCHIAVON, P VACCHI, A ZAMPA, N BIDOLI, V CANDUSSO, M CASOLINO, M DEPASCALE, MP MORSELLI, A PICOZZA, P SPARVOLI, R BOCCIOLINI, M CELLETTI, F FINETTI, N GRANDI, M PAPINI, P PEREGO, A PICCARDI, S SPILLANTINI, P BASINI, G BRANCACCIO, FM MAZZENGA, G RICCI, M BELLOTTI, R CAFAGNA, F CASTELLANO, M CIRCELLA, M DEMARZO, C DECATALDO, G GIGLIETTO, N MARANGELLI, B RAINO, A SPINELLI, P BRUNETTI, MT CODINO, A GRIMANI, C MENICHELLI, M MIOZZA, M BRONZINI, F GOLDEN, RL STOCHAJ, SJ STEPHENS, SA MITCHELL, JW ORMES, JF STREITMATTER, RE HOF, M MENN, W SIMON, M TI WIZARD SI-W IMAGING CALORIMETER - A PRELIMINARY-STUDY ON ITS PARTICLE IDENTIFICATION CAPABILITY DURING A BALLOON FLIGHT IN 1993 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT Frontier Detectors for Frontier Physics of the 6th Pisa Meeting on Advanced Detectors CY MAY 22-28, 1994 CL LA BIODOLA, ITALY SP ISTITUTO NAZL FIS NUCL, ITALIAN PHYS SOC, EUROPEAN PHYS SOC, UNIV PISA ID COSMIC-RAY POSITRONS; PROTOTYPE; SPACE AB The WiZard Collaboration is engaged in a program to study the antimatter components of the cosmic rays. A silicon-tungsten (Si-W) imaging calorimeter has been developed as part of this program. We present its performance and preliminary results, obtained during a balloon flight on September 8, 1993. The flight was dedicated to the measurement of the positron spectrum in the energy range 4-50 GeV and took place from Ft. Sumner, New Mexico. C1 UNIV TRIESTE, DIPARTMENTO FIS, I-34127 TRIESTE, ITALY. UNIV TRIESTE, SEZ INFN, I-34127 TRIESTE, ITALY. UNIV ROMA TOR VERGATA, DIPARTIMENTO FIS, I-00173 ROME, ITALY. UNIV ROMA TOR VERGATA, SEZ INFN, I-00173 ROME, ITALY. UNIV FLORENCE, DIPARTMENTO FIS, FLORENCE, ITALY. UNIV FLORENCE, SEZ INFN, FLORENCE, ITALY. IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY. UNIV BARI, DIPARTIMENTO FIS, BARI, ITALY. UNIV BARI, SEZ INFN, BARI, ITALY. UNIV PERUGIA, SEZ INFN, PERUGIA, ITALY. UNIV PERUGIA, DIPARTIMENTO FIS, PERUGIA, ITALY. UNIV ROMA LA SAPIENZA, DIPARTIMENTO FIS, I-00185 ROME, ITALY. UNIV ROMA LA SAPIENZA, SEZ INFN, I-00185 ROME, ITALY. NEW MEXICO STATE UNIV, LAS CRUCES, NM 88003 USA. TATA INST FUNDAMENTAL RES, BOMBAY 400005, MAHARASHTRA, INDIA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV SIEGEN, W-5900 SIEGEN, GERMANY. RI Morselli, Aldo/G-6769-2011; giglietto, nicola/I-8951-2012; Castellano, Marcello/J-3428-2012; Cafagna, Francesco/A-9299-2010; Vacchi, Andrea/C-1291-2010; OI Papini, Paolo/0000-0003-4718-2895; Morselli, Aldo/0000-0002-7704-9553; Boezio, Mirko/0000-0002-8015-2981; giglietto, nicola/0000-0002-9021-2888; Castellano, Marcello/0000-0002-4211-2903; Cafagna, Francesco/0000-0002-7450-4784; Vacchi, Andrea/0000-0003-3855-5856; Bellotti, Roberto/0000-0003-3198-2708; casolino, marco/0000-0001-6067-5104; Sparvoli, Roberta/0000-0002-6314-6117; Picozza, Piergiorgio/0000-0002-7986-3321 NR 15 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JUN 1 PY 1995 VL 360 IS 1-2 BP 17 EP 21 DI 10.1016/0168-9002(94)01217-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA RC354 UT WOS:A1995RC35400005 ER PT J AU KOLB, EW ABNEY, M COPELAND, E LIDDLE, AL LIDSEY, JE AF KOLB, EW ABNEY, M COPELAND, E LIDDLE, AL LIDSEY, JE TI THE INFLATION POTENTIAL FROM PRESENT-DAY OBSERVATIONS SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Workshop on Trends in Astroparticle Physics CY SEP 22-25, 1994 CL STOCKHOLM, SWEDEN ID DENSITY PERTURBATIONS; BACKGROUND-RADIATION; GRAVITATIONAL-WAVES; EXTENDED INFLATION; IRAS GALAXIES; ANISOTROPY; FIELD; COBE; EVOLUTION; VELOCITY AB Quantum fluctuation during the inflationary phase in the early Universe should leave their imprint on the present-day structure of the Universe. Here we discuss how to read this imprint in the cosmic microwave background and the large-scale structure of the Universe to discover something about the microphysics driving inflation. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. UNIV SUSSEX,SCH MATH & PHYS SCI,BRIGHTON BN1 9QH,E SUSSEX,ENGLAND. RP KOLB, EW (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB THEORET ASTROPHYS CTR,POB 500,BATAVIA,IL 60510, USA. NR 32 TC 3 Z9 3 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 JUN PY 1995 SU 43 BP 118 EP 125 PG 8 WC Physics, Particles & Fields SC Physics GA RF481 UT WOS:A1995RF48100020 ER PT J AU ORMES, JF AF ORMES, JF TI THE NASA PROGRAM IN ASTROPARTICLE PHYSICS SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Workshop on Trends in Astroparticle Physics CY SEP 22-25, 1994 CL STOCKHOLM, SWEDEN ID GAMMA-RAYS; PULSAR AB The program related to Astroparticle Physics studies in the Laboratory for High Energy Astrophysics at NASA's Goddard Space Flight Center are described. This paper focuses on the results from the Compton Gamma Ray Observatory, ROSAT, and ASCA, missions which study emissions from very hot plasmas, nuclear processes and high energy particle interactions in space. Results to be discussed include gamma ray beaming from Active Galactic Nuclei, gamma ray emission from pulsars, radioactive elements in the interstellar medium, X-ray emission from clusters of galaxies, and the progress being made to unravel the gamma ray burst mystery. Future planned missions such as the X-ray Timing Explorer and Astro-E are also discussed. RP ORMES, JF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 54 TC 0 Z9 0 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 JUN PY 1995 SU 43 BP 194 EP 207 DI 10.1016/0920-5632(95)00476-P PG 14 WC Physics, Particles & Fields SC Physics GA RF481 UT WOS:A1995RF48100034 ER PT J AU WEST, EA SMITH, MH AF WEST, EA SMITH, MH TI POLARIZATION ERRORS ASSOCIATED WITH BIREFRINGENT WAVEPLATES SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Polarization Analysis and Measurement II CY JUL 25-27, 1994 CL SAN DIEGO, CA SP SOC PHOTO OPT INSTRUMENTAT ENGINEERS DE POLARIZATION ANALYSIS AND MEASUREMENT; WAVEPLATES; RETARDATION; POLARIMETRY AB Although zero-order quartz waveplates are widely used in instrumentation that needs good temperature and field-of-view characteristics, the residual errors associated with these devices can be very important in high-resolution polarimetry measurements. How the field-of-View characteristics are affected by retardation errors and the misalignment of optic axes in a double-crystal waveplate is discussed, The retardation measurements made on zero-order quartz and single-order ''achromatic'' waveplates and how the misalignment errors affect those measurements are discussed. RP WEST, EA (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,ES82,HUNTSVILLE,AL 35812, USA. NR 4 TC 13 Z9 15 U1 0 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 JUN PY 1995 VL 34 IS 6 BP 1574 EP 1580 DI 10.1117/12.202079 PG 7 WC Optics SC Optics GA RC347 UT WOS:A1995RC34700007 ER PT J AU WILSON, MA POHORILLE, A JENNISKENS, P BLAKE, DF AF WILSON, MA POHORILLE, A JENNISKENS, P BLAKE, DF TI PROBING THE STRUCTURE OF COMETARY ICE SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article; Proceedings Paper CT 1993 International-Society-for-the-Study-of-the-Origin-of-Life (ISSOL) Meeting CY 1993 CL BARCELONA, SPAIN SP INT SOC STUDY ORIGIN LIFE ID PRESSURE-INDUCED AMORPHIZATION; DENSITY AMORPHOUS WATER; LIQUID VAPOR INTERFACE; MOLECULAR-DYNAMICS; BEHAVIOR; CLUSTER; SPECTRA; GROWTH AB Computer simulations of bulk and vapor deposited amorphous ices are presented. The structure of the bulk low density amorphous ice is in good agreement with experiments on pressure disordered amorphous ice. Both the low density bulk ice and the vapor deposited ices exhibit strong ordering. Vapor deposition of hot (300 K) water molecules onto a cold (77 K) substrate yields less porous ices than deposition of cold (77 K) water molecules onto a cold subtrate. Both vapor deposited ices are more porous than the bulk amorphous ice. The structure of bulk high density amorphous ice is only in fair agreement with experimental results. Attempts to simulate high density amorphous ice via vapor deposition were not successful. Electron diffraction results on vapor deposited amorphous ice indicate that the temperature of the nucleation of the cubic phase depends upon the amount of time between the deposition and the onset of crystallization, suggesting that freshly deposited ice layers reconstruct on times of the order of hours. The temperature dependence of the microporosity of the vapor deposited amorphous ices might affect laboratory experiments that are aimed at simulating astrophysical ices in the context of the origin of prebiotic organic material and its transport to the Earth. C1 UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. RP WILSON, MA (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. FU NCI NIH HHS [NCA2-604] NR 32 TC 12 Z9 12 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol Biosph. PD JUN PY 1995 VL 25 IS 1-3 BP 3 EP 19 DI 10.1007/BF01581570 PG 17 WC Biology SC Life Sciences & Biomedicine - Other Topics GA QG487 UT WOS:A1995QG48700002 PM 11536679 ER PT J AU POHORILLE, A WILSON, MA AF POHORILLE, A WILSON, MA TI MOLECULAR-DYNAMICS STUDIES OF SIMPLE MEMBRANE WATER INTERFACES - STRUCTURE AND FUNCTIONS IN THE BEGINNINGS OF CELLULAR LIFE SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article; Proceedings Paper CT 1993 International-Society-for-the-Study-of-the-Origin-of-Life (ISSOL) Meeting CY 1993 CL BARCELONA, SPAIN SP INT SOC STUDY ORIGIN LIFE ID LIQUID VAPOR INTERFACE; LIPID BILAYER-MEMBRANES; ALANINE DIPEPTIDE; BASIC PEPTIDES; MONTE-CARLO; PERMEABILITY; MODEL; EQUILIBRIUM; SOLVATION; EVOLUTION AB Molecular dynamics computer simulations of the structure and functions of a simple membrane are performed in order to examine whether membranes provide an environment capable of promoting protobiological evolution. Our model membrane is composed of glycerol 1-monooleate. It is found that the bilayer surface fluctuates in time and space, occasionally creating thinning defects in the membrane. These defects are essential for passive transport of simple ions across membranes because they reduce the Born barrier to this process by approximately 40%. Negative ions are transferred across the bilayer more readily than positive ions due to favorable interactions with the electric field at the membrane-water interface. Passive transport of neutral molecules is, in general, more complex than predicted by the solubility-diffusion model. In particular, molecules which exhibit sufficient hydrophilicity and lipophilicity concentrate near membrane surfaces and experience ''interfacial resistance'' to transport. The membrane-water interface forms an environment suitable for heterogeneous catalysis. Several possible mechanisms leading to an increase of reaction rates at the interface are discussed. We conclude that vesicles have many properties that make them very good candidates for earliest protocells. Some potentially fruitful directions of experimental and theoretical research on this subject are proposed. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP POHORILLE, A (reprint author), UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143, USA. NR 67 TC 31 Z9 31 U1 0 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol Biosph. PD JUN PY 1995 VL 25 IS 1-3 BP 21 EP 46 DI 10.1007/BF01581571 PG 26 WC Biology SC Life Sciences & Biomedicine - Other Topics GA QG487 UT WOS:A1995QG48700003 PM 11536672 ER PT J AU WEBER, AL AF WEBER, AL TI PREBIOTIC POLYMERIZATION - OXIDATIVE POLYMERIZATION OF 2,3-DIMERCAPTO-1-PROPANOL ON THE SURFACE OF IRON(III) HYDROXIDE OXIDE SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article; Proceedings Paper CT 1993 International-Society-for-the-Study-of-the-Origin-of-Life (ISSOL) Meeting CY 1993 CL BARCELONA, SPAIN SP INT SOC STUDY ORIGIN LIFE ID CONDENSATION-REACTIONS; ACID SYNTHESIS; GLYCERALDEHYDE; ENERGY; HYDROGEN; SUSPENSIONS; DISULFIDES; THIOESTERS; THIOL AB The oxidation of 2,3-dimercapto-1-propanol by ferric ions on the surface of iron(III) hydroxide oxide (Fe(OH)O) yielded polydisulfide oligomers. This polymerization occurred readily at low dithiol concentration under mild aqueous conditions. Polydisulfide polymers up to the 15-mer were synthesized from 1 mM dithiol in 5 ml water reacted with iron(III) hydroxide oxide (20 mg, 160 mu mole Fe) for 3 days under anaerobic conditions at 40 degrees C and pH 4. About 91% of the dithiol was converted to short soluble oligomers and 9% to insoluble larger oligomers that were isolated with the Fe(OH)O phase. Reactions carried out at the same ratio of dithiol to Fe(OH)O but at higher dithiol concentrations gave higher yields of the larger insoluble oligomers. The relationship of these results to prebiotic polymer synthesis is discussed. RP WEBER, AL (reprint author), NASA,AMES RES CTR,SETI INST,MAIL STOP 239-4,MOFFETT FIELD,CA 94035, USA. NR 33 TC 5 Z9 5 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol Biosph. PD JUN PY 1995 VL 25 IS 1-3 BP 53 EP 60 DI 10.1007/BF01581573 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA QG487 UT WOS:A1995QG48700005 PM 11536681 ER PT J AU RUBINCAM, DP AF RUBINCAM, DP TI HAS CLIMATE CHANGED THE EARTHS TILT SO PALEOCEANOGRAPHY LA English DT Article ID PLEISTOCENE DEGLACIATION; CHAOTIC OBLIQUITY; MARS; INSOLATION; ROTATION; REGOLITH; HISTORY; SYSTEM; FIELD AB Have the ice ages secularly altered the obliquity (axial tilt) of the Earth over geologic time? The waxing and waning of ice caps in response to obliquity oscillations plus mantle adjustment to the weight of the caps alter the Earth's dynamical flattening. This affects the lunar and solar torques on the Earth so as to secularly change the Earth's axial tilt. This mechanism is dubbed ''climate friction,'' since analogous to tidal friction, it arises from lags in the Earth's response to cyclic external forcing. But the existence of two processes, ice cap waxing and waning and mantle viscous flow, can lead to either an increase or decrease in the obliquity. Evidence indicates that the growth and decay of the ice caps greatly lag the orbital forcing; this causes the axial tilt to increase with time. But the ice cap effects are partly canceled by viscous compensation in the mantle. Low mantle viscosities (about 10(21) Pa . s) lead to rapid compensation and have only a slight effect on obliquity. High viscosities (about 10(22) Pa . s) slow the compensation enough so that there could be significant secular change in the obliquity over geologic time, perhaps explaining all of the present tilt of 23.5 degrees. However, in addition to the current uncertainty as to the effective viscosity of the mantle, knowledge of past ice ages is incomplete, so that the amount of obliquity increase presently remains unknown. RP RUBINCAM, DP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GEODYNAM BRANCH,CODE 921,GREENBELT,MD 20771, USA. RI Rubincam, David/D-2918-2012 NR 42 TC 17 Z9 17 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD JUN PY 1995 VL 10 IS 3 BP 365 EP 372 DI 10.1029/95PA00578 PG 8 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA RG337 UT WOS:A1995RG33700002 ER PT J AU WINKER, D AF WINKER, D TI LIDAR IN-SPACE - THE VIEW FROM AFAR SO PHOTONICS SPECTRA LA English DT Note RP WINKER, D (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU LAURIN PUBL CO INC PI PITTSFIELD PA BERKSHIRE COMMON PO BOX 1146, PITTSFIELD, MA 01202 SN 0731-1230 J9 PHOTON SPECTRA JI Photon. Spect. PD JUN PY 1995 VL 29 IS 6 BP 102 EP 103 PG 2 WC Optics SC Optics GA RB100 UT WOS:A1995RB10000041 ER PT J AU VASQUEZ, RP RUPP, M GUPTA, A TSUEI, CC AF VASQUEZ, RP RUPP, M GUPTA, A TSUEI, CC TI ELECTRONIC-STRUCTURE OF HGBA2CACU2O6+DELTA EPITAXIAL-FILMS MEASURED BY X-RAY PHOTOEMISSION SO PHYSICAL REVIEW B LA English DT Note ID HIGH-TC SUPERCONDUCTORS; PHOTOELECTRON-SPECTROSCOPY; SINGLE-CRYSTALS; OXYGEN C1 IBM CORP,DIV RES,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP VASQUEZ, RP (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109, USA. NR 22 TC 15 Z9 15 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 1995 VL 51 IS 21 BP 15657 EP 15660 DI 10.1103/PhysRevB.51.15657 PG 4 WC Physics, Condensed Matter SC Physics GA RC329 UT WOS:A1995RC32900111 ER PT J AU GIRIMAJI, SS SPEZIALE, CG AF GIRIMAJI, SS SPEZIALE, CG TI A MODIFIED RESTRICTED EULER EQUATION FOR TURBULENT FLOWS WITH MEAN VELOCITY-GRADIENTS SO PHYSICS OF FLUIDS LA English DT Article ID TENSOR; FLUID C1 BOSTON UNIV,DEPT MECH & AEROSP ENGN,BOSTON,MA 02215. RP GIRIMAJI, SS (reprint author), NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681, USA. NR 8 TC 14 Z9 14 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUN PY 1995 VL 7 IS 6 BP 1438 EP 1446 DI 10.1063/1.868530 PG 9 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RA446 UT WOS:A1995RA44600025 ER PT J AU LEBOEUF, RL MEHTA, RD AF LEBOEUF, RL MEHTA, RD TI ON USING TAYLORS HYPOTHESIS FOR 3-DIMENSIONAL MIXING LAYERS SO PHYSICS OF FLUIDS LA English DT Note C1 STANFORD UNIV,JIAA,DEPT AERONAUT & ASTRONAUT,STANFORD,CA 94305. NASA,AMES RES CTR,FLUID MECH LAB,MOFFETT FIELD,CA 94035. RP LEBOEUF, RL (reprint author), STANFORD UNIV,CTR TURBULENCE RES,STANFORD,CA 94305, USA. NR 10 TC 15 Z9 15 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUN PY 1995 VL 7 IS 6 BP 1516 EP 1518 DI 10.1063/1.868539 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RA446 UT WOS:A1995RA44600034 ER PT J AU PIASTUCH, WC STRYJEWSKI, EC AF PIASTUCH, WC STRYJEWSKI, EC TI ARABIDOPSIS-THALIANA GROWTH, MORPHOLOGY AND ULTRASTRUCTURE AT ELEVATED AND SUPER-ELEVATED CO2 CONCENTRATIONS SO PLANT PHYSIOLOGY LA English DT Meeting Abstract C1 DYNAMAC CORP,NASA,PLANT SPACE BIOL LAB,KENNEDY SPACE CTR,FL. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD JUN PY 1995 VL 108 IS 2 SU S BP 62 EP 62 PG 1 WC Plant Sciences SC Plant Sciences GA RE289 UT WOS:A1995RE28900300 ER PT J AU FREIBELMAN, WA AF FREIBELMAN, WA TI THE IUE ABSORPTION-SPECTRUM OF THE NUCLEUS OF NGC-246 - MOSTLY C-IV AND O-VI SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID ULTRAVIOLET-SPECTRUM; TERM ANALYSIS AB We present a list of more than 140 absorption features and their equivalent widths for the central star of the planetary nebula NGC 246 as observed in the wavelength range lambda1169-lambda2000. High signal-to-noise ratios are achieved by coadding nine high-dispersion SWP spectra, representing a total of nearly 22 hr observing time. The IUE spectrum is dominated by strong absorption lines, or blends, of O VI and C IV. Other ions include N v, O v, Si iv, Fe Vi, Fe VII, and Ne VII, plus interstellar absorption lines. The only feature to display a P Cygni profile is the C IV resonance doublet from which a terminal wind velocity of 4120 +/- 200 km s-1 is derived. RP FREIBELMAN, WA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 684,GREENBELT,MD 20771, USA. NR 19 TC 13 Z9 13 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JUN PY 1995 VL 107 IS 712 BP 531 EP 540 DI 10.1086/133588 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RC140 UT WOS:A1995RC14000006 ER PT J AU BANKS, HT SMITH, RC WANG, Y AF BANKS, HT SMITH, RC WANG, Y TI THE MODELING OF PIEZOCERAMIC PATCH INTERACTIONS WITH SHELLS, PLATES, AND BEAMS SO QUARTERLY OF APPLIED MATHEMATICS LA English DT Article ID PIEZOELECTRIC ACTUATORS AB General models describing the interactions between one or a pair of piezoceramic patches and elastic substructures consisting of a cylindrical shell, plate, or beam are presented, In each case, the contributions to the internal moments and forces due to the presence of the patches are carefully discussed, In addition to these material contributions, the input of voltage to the patches produces mechanical strains that lead to external moments and forces, These external loads depend on the material properties of the patch, the geometry of patch placement, and the voltage, The internal and external moments and forces due to the patches are then incorporated into the equations of motion, which yields models describing the dynamics of the combined structure. These models are sufficiently general to allow for potentially different patch voltages, which implies that they can be suitably employed when using piezoceramic patches for controlling system dynamics when both extensional and bending vibrations are present. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP BANKS, HT (reprint author), N CAROLINA STATE UNIV,RALEIGH,NC 27695, USA. NR 23 TC 80 Z9 81 U1 0 U2 1 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 SN 0033-569X J9 Q APPL MATH JI Q. Appl. Math. PD JUN PY 1995 VL 53 IS 2 BP 353 EP 381 PG 29 WC Mathematics, Applied SC Mathematics GA RA178 UT WOS:A1995RA17800010 ER PT J AU GAO, BC GOETZ, AFH AF GAO, BC GOETZ, AFH TI RETRIEVAL OF EQUIVALENT WATER THICKNESS AND INFORMATION RELATED TO BIOCHEMICAL-COMPONENTS OF VEGETATION CANOPIES FROM AVIRIS DATA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID INFRARED REFLECTANCE; CHEMISTRY; STRESS; LEAVES AB Remote sensing of water status and biochemical components of vegetation can have important applications in the fields of agriculture and forestry. Reflectance of fresh, green vegetation in the 1.0-2.5 mu m region is dominated by liquid water absorption and also weakly affected by absorption due to biochemical components, such as protein, lignin, and cellulose. We have developed both the nonlinear and linear least squares spectrum-matching techniques for deriving equivalent water thickness (EWT) of vegetation from AVIRIS data in the 1.0 mu m and 1.6 mu m regions. EWT values are compared with in situ canopy measurements in Harvard Forest, Massachusetts. Seasonal variations of EWTs over an agricultural area in Greeley, Colorado are determined. EWTs from the 1.0 mu m region are generally greater than those from the 1.6 mu m region. This is because the absorptivity of water near 1.0 mu m is much less than that at 1.6 mu m-resulting in a greater mean absorption path length in the 1.0 mu m region. After fitting the AVIRIS data with a reflectance spectrum of water, a weak lignin-cellulose absorption feature centered at 1.72 mu m is seen in the difference spectra. We map the depth of the 1.72-mu m feature, which can be considered as an index of abundance of those compounds in the canopy. AVIRIS data for the Harvard Forest, Massachusetts were analyzed and compared with laboratory chemical analysis of the foliage. The results obtained with the linear least squares spectrum-matching technique are comparable to the stepwise linear regression results obtained from first difference spectra. C1 UNIV COLORADO,CIRES,CTR STUDY EARTH SPACE,BOULDER,CO 80309. UNIV COLORADO,DEPT GEOL SCI,BOULDER,CO 80309. RP GAO, BC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 913,GREENBELT,MD 20771, USA. NR 31 TC 121 Z9 127 U1 2 U2 20 PU ELSEVIER SCIENCE PUBL CO 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 JUN PY 1995 VL 52 IS 3 BP 155 EP 162 DI 10.1016/0034-4257(95)00039-4 PG 8 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RG826 UT WOS:A1995RG82600001 ER PT J AU MORAN, MS JACKSON, RD CLARKE, TR QI, J CABOT, F THOME, KJ MARKHAM, BL AF MORAN, MS JACKSON, RD CLARKE, TR QI, J CABOT, F THOME, KJ MARKHAM, BL TI REFLECTANCE FACTOR RETRIEVAL FROM LANDSAT TM AND SPOT HRV DATA FOR BRIGHT AND DARK TARGETS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID THEMATIC MAPPER DATA; SURFACE REFLECTANCE; SATELLITE; SENSOR; CALIBRATION; VEGETATION; IMAGERY AB In recent years, there have been many land-surface studies based on visible and near-infrared reflectance values retrieved from the Landsat Thematic Mapper (TM) and SPOT High Resolution. Visible (HRV) sensors. Retrieval of reflectance from. satellite sensor digital count requires knowledge of the atmospheric conditions and the sensor absolute calibration. In most cases, atmospheric conditions are simulated with a radiative transfer code and sensor calibration coefficients are obtained from preflight sensor calibrations or in-flight calibrations over bright surfaces (such as White Sands, New Mexico, USA, or La Crau, France). Though these procedures are well accepted, there have been few studies specifically designed to validate the accuracy of such reflectance factor retrievals (RFR) for both bright and dark targets. Data from two experiments conducted in an agricultural region in central Arizona were analyzed to quantify the accuracy of RFR from the Landsat TM and SPOT HRV sensors. These data included measurements made with groundbased and aircraft-based four-band radiometers and the NASA Advanced Solid-State Array Spectrometer (ASAS) aboard a C130 aircraft, and TM and HRV images acquired at nadir and off-nadir viewing angles. Results showed that the off-nadir reflectance factors measured using ground- and aircraft-based instruments, including ASAS, were comparable. The RFR from the satellite-based TM and HRV sensors generally resulted in an overestimation of dark target reflectance (up to 0.05 reflectance in the visible) and an underestimation of bright target reflectance (up to 0.1 reflectance in the near-infrared). Even greater error was possible when RFR was based on outdated sensor calibrations, particularly those conducted prelaunch. There was supporting evidence from studies at three sites (White Sands, New Mexico; Maricopa, Arizona; and Walnut Gulch, Arizona) that the Landsat-5 TM sensor sensitivity may have degraded by as much as 20% from the prelaunch calibration. Regarding the potential error in RFR related to recent changes in the processing of Landsat TM data (Level-0 and Level-1) by EOSAT Corporation, we found that the Level-0 data was slightly greater (similar to 2 digital counts) than the Level-1 data for all bands and all targets in our study. C1 USDA ARS,US WATER CONSERVAT LAB,PHOENIX,AZ 85040. LERTS,TOULOUSE,FRANCE. UNIV ARIZONA,CTR OPT SCI,TUCSON,AZ. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Thome, Kurtis/D-7251-2012; Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 34 TC 30 Z9 30 U1 1 U2 3 PU ELSEVIER SCIENCE PUBL CO 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 JUN PY 1995 VL 52 IS 3 BP 218 EP 230 DI 10.1016/0034-4257(95)00035-Y PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA RG826 UT WOS:A1995RG82600007 ER PT J AU JOHNSON, MG LEVINE, ER KERN, JS AF JOHNSON, MG LEVINE, ER KERN, JS TI SOIL ORGANIC-MATTER - DISTRIBUTION, GENESIS, AND MANAGEMENT TO REDUCE GREENHOUSE-GAS EMISSIONS SO WATER AIR AND SOIL POLLUTION LA English DT Article ID CARBON-DIOXIDE; FOREST SOILS; NITROGEN; TEMPERATE; STORAGE; METHANE; SINKS AB In this paper we describe the accumulation of soil organic matter (SOM) during pedogenesis and the processes that can lead to the emission of greenhouse gases (CO2, CH4, N2O) to the atmosphere via SOM decomposition and denitrification. We discuss the role of management on SOM accumulation and loss, and the potential for controlling emission or comsumption of greenhouse gases by soils. We conclude that under current climate conditions there are global scale opportunities to reduce greenhouse gas emissions from soils and increase the indirect sequestration of greenhouse gases in soils through improved soil management. C1 NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771. RP JOHNSON, MG (reprint author), US EPA,MANTECH ENVIRONM TECHNOL INC,ENVIRONM RES LAB,200 SW 35TH ST,CORVALLIS,OR 97333, USA. NR 68 TC 33 Z9 42 U1 2 U2 13 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD JUN PY 1995 VL 82 IS 3-4 BP 593 EP 615 DI 10.1007/BF00479414 PG 23 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA RW860 UT WOS:A1995RW86000004 ER PT J AU WANG, LP GRANDHI, RV HOPKINS, DA AF WANG, LP GRANDHI, RV HOPKINS, DA TI STRUCTURAL RELIABILITY OPTIMIZATION USING AN EFFICIENT SAFETY INDEX CALCULATION PROCEDURE SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE PROBALILISTIC ANALYSIS; OPTIMIZATION; SAFETY INDEX; STRUCTURAL RELIABILITY AB The objective of-this paper is to conduct reliability-based Structural optimization in a multidisciplinary environment. An efficient reliability analysis is developed by expanding the limit functions in terms of intermediate design variables. The design constraints are approximated using multivariate splines in searching for the optimum. The reduction in computational cost realized, in safety index calculation and optimization are demonstrated through several structural problems. This paper presents safety index computation, analytical sensitivity analysis of reliability constraints and optimization using truss, frame and plate examples. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP WANG, LP (reprint author), WRIGHT STATE UNIV,DEPT MECH & MAT ENGN,DAYTON,OH 45435, USA. NR 20 TC 28 Z9 29 U1 0 U2 3 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 MAY 30 PY 1995 VL 38 IS 10 BP 1721 EP 1738 DI 10.1002/nme.1620381008 PG 18 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA QX109 UT WOS:A1995QX10900007 ER PT J AU IGA, I SRIVASTAVA, SK AF IGA, I SRIVASTAVA, SK TI DISSOCIATIVE ELECTRON-ATTACHMENT TO OCS SO THEOCHEM-JOURNAL OF MOLECULAR STRUCTURE LA English DT Article; Proceedings Paper CT VIIth Brazilian Symposium of Theoretical Chemistry CY NOV 21-24, 1993 CL CAXAMBU, BRAZIL ID CARBON-DIOXIDE; IMPACT; EXCITATION; FRAGMENTS; CS2 AB The formation of S- and C- ions from electron impact on OCS has been investigated by using a crossed electron beam-molecular beam collision geometry. Measured appearance energies and peak energies for the formation of S- and C- ions are reported. These data were then used to identify the various channels of dissociation by employing Hess's law. It is shown that OCS, although isoelectronic in the valence shell, does not conform in its attachment properties to CO2 and CS2. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP IGA, I (reprint author), UNIV FED SAO CARLOS,DEPT QUIM,BR-13565905 SAO CARLOS,SP,BRAZIL. RI Iga, Ione/C-1273-2015 NR 21 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 THEOCHEM-J MOL STRUC JI Theochem-J. Mol. Struct. PD MAY 30 PY 1995 VL 335 BP 31 EP 36 PG 6 WC Chemistry, Physical SC Chemistry GA RE187 UT WOS:A1995RE18700005 ER PT J AU SCHRAMM, DN AF SCHRAMM, DN TI COSMOLOGY AND UNSTABLE NUCLEI SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT International Symposium on Physics of Unstable Nuclei CY OCT 31-NOV 03, 1994 CL NIIGATA, JAPAN SP NIIGATA UNIV, FAC SCI, UNIV TOKYO, INST NUCL STUDY, INST PHYS & CHEM RES ID BIG-BANG NUCLEOSYNTHESIS; HADRON PHASE-TRANSITION; GALACTIC COSMIC-RAYS; PRIMORDIAL NUCLEOSYNTHESIS; HALO-STARS; INTERSTELLAR-MEDIUM; NEUTRON LIFETIME; EARLY UNIVERSE; EARLY GALAXY; ABUNDANCES AB Primordial nucleosynthesis has established itself as one of the three pillars of Big Bang cosmology. Many of the Big Bang Nucleosynthesis reactions involve unstable nuclei. Hence, there is a tight relationship between the subject of this conference and cosmology. The prime role of unstable nuclei in cosmology is related to lithium synthesis and the lack of cosmological synthesis of Be and B. These nuclei will thus be focused upon. Nucleosynthesis involves comparing calculated abundances with observed abundances. In general abundance determinations are dominated by systematic rather than statistical errors, and work on bounding systematics is crucial. The quark-hadron inspired inhomogeneous calculations now unanimously agree that only relatively small variations in Omega(b) are possible vis-a-vis the homogeneous model; hence, the robustness of Omega(b) similar to 0.05 is now apparent. (These calculations depend critically on unstable nuclei.) The above argues that the bulk of the baryons in the universe are not producing visible light. A comparison with the ROSAT cluster data is also shown to be consistent with the standard BBN model. Omega(b) similar to 1 seems to be definitely excluded, so, if Omega(TOTAL) = 1, as some recent observations may hint, then non-baryonic dark matter is required. The implications of the recently reported halo microlensing events are discussed. In summary, it is argued that the physics of unstable nuclei affects the fundamental dark matter argument. RP SCHRAMM, DN (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BOX 500,BATAVIA,IL 60510, USA. NR 103 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD MAY 29 PY 1995 VL 588 IS 1 BP C277 EP C293 DI 10.1016/0375-9474(95)00152-Q PG 17 WC Physics, Nuclear SC Physics GA RC095 UT WOS:A1995RC09500049 ER PT J AU LAPORTE, RE MARLER, E AKAZAWA, S SAUER, F GAMBOA, C SHENTON, C GLOSSER, C VILLASENOR, A MACLURE, M AF LAPORTE, RE MARLER, E AKAZAWA, S SAUER, F GAMBOA, C SHENTON, C GLOSSER, C VILLASENOR, A MACLURE, M TI THE DEATH OF BIOMEDICAL JOURNALS SO BRITISH MEDICAL JOURNAL LA English DT Article C1 AT&T GIS,GRP ENTERPRISE DESIGN & DEV,BOCA RATON,FL 33434. PAN AMER HLTH ORG,WASHINGTON,DC. STERLING SOFTWARE,WASHINGTON,DC. NASA,SCI INTERNET,WASHINGTON,DC 20546. HARVARD UNIV,DEPT EPIDEMIOL,CAMBRIDGE,MA. RP LAPORTE, RE (reprint author), UNIV PITTSBURGH,DEPT EPIDEMIOL,3460 5TH AVE,PITTSBURGH,PA 15213, USA. NR 9 TC 92 Z9 96 U1 0 U2 1 PU BRITISH MED JOURNAL PUBL GROUP PI LONDON PA BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON, ENGLAND WC1H 9JR SN 0959-8138 J9 BRIT MED J JI Br. Med. J. PD MAY 27 PY 1995 VL 310 IS 6991 BP 1387 EP 1390 PG 4 WC Medicine, General & Internal SC General & Internal Medicine GA RB005 UT WOS:A1995RB00500031 PM 7787546 ER PT J AU FERGUSON, EW VILLASENOR, A CUNNION, S DEGOYET, CD YOUNG, FE LAPORTE, RE AF FERGUSON, EW VILLASENOR, A CUNNION, S DEGOYET, CD YOUNG, FE LAPORTE, RE TI A GLOBAL HEALTH DISASTER NETWORK IS NEEDED SO BRITISH MEDICAL JOURNAL LA English DT Letter C1 NASA HQ,OSSA INFORMAT SYST,OFF SPACE SCI & APPLICAT,NASA SCI NETWORKING,WASHINGTON,DC 20546. UNIFORMED SERV UNIV HLTH SCI,DEPT PREVENT MED & BIOMETR,BETHESDA,MD 20814. PAN AMER HLTH ORG,EMERGENCY PREPAREDNESS & DISASTER RELIEF COORDINA,WASHINGTON,DC 20037. US DEPT HHS,NDMS,OFF EMERGENCY PREPAREDNESS,ROCKVILLE,MD 20857. UNIV PITTSBURGH,GRAD SCH PUBL HLTH,DEPT EPIDEMIOL,PITTSBURGH,PA 15261. RP FERGUSON, EW (reprint author), NASA HQ,LIFE & MICROGRAV SCI & APPLICAT,AEROSP MED & OCCUOPAT HLTH,CODE UO,WASHINGTON,DC 20546, USA. NR 3 TC 6 Z9 6 U1 0 U2 2 PU BRITISH MED JOURNAL PUBL GROUP PI LONDON PA BRITISH MED ASSOC HOUSE, TAVISTOCK SQUARE, LONDON, ENGLAND WC1H 9JR SN 0959-8138 J9 BRIT MED J JI Br. Med. J. PD MAY 27 PY 1995 VL 310 IS 6991 BP 1412 EP 1412 PG 1 WC Medicine, General & Internal SC General & Internal Medicine GA RB005 UT WOS:A1995RB00500074 PM 7787575 ER PT J AU JOSLIN, RD AF JOSLIN, RD TI DIRECT SIMULATION OF EVOLUTION AND CONTROL OF 3-DIMENSIONAL INSTABILITIES IN ATTACHMENT-LINE BOUNDARY-LAYERS SO JOURNAL OF FLUID MECHANICS LA English DT Article ID STABILITY; FLOW AB The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier-Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer hows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities. RP JOSLIN, RD (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH & ACOUST,MAIL STOP 170,HAMPTON,VA 23681, USA. NR 26 TC 28 Z9 28 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAY 25 PY 1995 VL 291 BP 369 EP 392 DI 10.1017/S0022112095002746 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA RB671 UT WOS:A1995RB67100015 ER PT J AU RIGNOT, E AF RIGNOT, E TI BACKSCATTER MODEL FOR THE UNUSUAL RADAR PROPERTIES OF THE GREENLAND ICE-SHEET SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID OUTER PLANET SATELLITES; COHERENT-BACKSCATTER; RANDOM-MEDIA; SCATTERING; SURFACE; LIGHT; POLARIZATION; GANYMEDE; REFLECTIVITY; PARTICLES AB A number of planetary objects exhibit large radar reflectivity and polarization ratios, and more recently, a similar behavior has been observed over a vast portion of the Earth's surface: the percolation facies of the Greenland Ice Sheet. Surface-based ranging radar data and snow stratigraphy studies demonstrated that the radar properties of that portion of Greenland are caused by enhanced scattering from massive, large, solid-ice bodies buried in the top few meters of the dry, cold, clean snowy surface of the ice sheet and created by seasonal melting and refreezing events. Here, we model the icy inclusions as randomly oriented, discrete, noninteracting, dielectric cylinders embedded in a transparent snow medium. An exact analytical solution is used to compute the scattered field from the cylinders. Using this model, we correctly predict the polarimetric radar observations gathered by an airborne imaging system at three wavelengths (5.6, 24, and 68 cm), between 19 degrees and 65 degrees incidence angle. The diameter and number density of the cylinders that are inferred from the radar data using the model are consistent with in situ observations of the icy inclusions. The large radar reflectivity and polarization ratios are interpreted as arising from internal reflections of the radar signals in the icy inclusions that first-order external reflection models fail to predict. The results compare favorably with predictions from the coherent backscatter or weak localization theory and may provide a complementary framework for interpreting exotic radar echoes from other planetary objects. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MAIL STOP 300-243, PASADENA, CA 91109 USA. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 49 TC 41 Z9 41 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1995 VL 100 IS E5 BP 9389 EP 9400 DI 10.1029/95JE00485 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RA507 UT WOS:A1995RA50700002 ER PT J AU BOGARD, DD NYQUIST, LE BANSAL, BM GARRISON, DH WIESMANN, H HERZOG, GF ALBRECHT, AA VOGT, S KLEIN, J AF BOGARD, DD NYQUIST, LE BANSAL, BM GARRISON, DH WIESMANN, H HERZOG, GF ALBRECHT, AA VOGT, S KLEIN, J TI NEUTRON-CAPTURE CL-36, CA-41, AR-36, AND SM-150 IN LARGE CHONDRITES - EVIDENCE FOR HIGH FLUENCES OF THERMALIZED NEUTRONS SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID COSMIC-RAY EXPOSURE; ANGRA-DOS-REIS; PRODUCTION-RATES; COSMOGENIC NUCLIDES; NOBLE-GASES; DATA COMPILATION; METEORITES; AGES; HISTORIES; ANGRITES AB We have measured significant concentrations of Cl-36, Ca-41, Ar-36 from decay of Cl-36, and Sm-150 produced from the capture of thermalized neutrons in the large Chico L6 chondrite. Activities of Cl-36 and Ca-41, corrected for a high-energy spallogenic component and a terrestrial age of similar to 50 ka, give average neutron-capture production rates of 208 atoms/min/g-Cl and 1525 atoms/min/kg-Ca, which correspond to thermal neutron (n) fluxes of 6.2 n/cm(2)/s and 4.3 n/cm(2)/s, respectively. If sustained for the similar to 65 Ma single-stage, cosmic ray exposure age of Chico, these values correspond to thermal neutron fluences of similar to 1.3x10(16) and 0.8x10(16) n/cm(2) for Cl-36 and Ca-41, respectively. Stepwise temperature extraction of Ar in Chico impact melt shows Ar-36/Ar-38 ratios as large as similar to 9. The correlation of high Ar-36/Ar-38 With high Cl/Ca phases in neutron-irradiated Chico indicates that the excess Ar-36 above that expected from spallation is due to decay of neutron-produced Cl-36. Excess Ar-36 in Chico requires a thermal neutron fluence of 0.9-1.7x10(16) n/cm(2). Decreases in Sm-149/Sm-152 due to neutron-capture by Sm-149 correlate with increases in Sm-150/Sm-152 for three samples of Chico, and one of the Torino H-chondrite. The 0.08% decrease in Sm-149/Sm-152 shown by Chico corresponds to a neutron fluence of 1.23x10(16) n/cm(2). This fluence derived from Sm considers capture of epithermal neutrons and effects of chemical composition on the neutron energy distribution. Excess Ar-36 identified in the Arapahoe, Bruderheim, and Torino chondrites and the Shallowater aubrite suggest exposure to neutron fluences of similar to 0.2-0.6x10(16) n/cm(2). Depletion of Sm-149 in Torino and the LEW86010 angrite suggest neutron fluences of 0.8x10(16) n/cm(2) and 0.25x10(16) n/cm(2), respectively. Neutron fluences of similar to 10(16) n/cm(2) in Chico are almost as large as those previously observed for some lunar soils. Consideration of exposure ages suggests that the neutron flux in Chico may have been greater than that in many lunar soils. Neutron-capture effects, although seldom reported, may be common for large meteorites and could affect calculation of exposure ages based on cosmogenic Ar. Combining measurements of radioactive and stable species produced from neutron-capture has the potential for identifying large meteorites with complex exposure histories. C1 LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. RUTGERS STATE UNIV,DEPT CHEM,NEW BRUNSWICK,NJ 08903. UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. RP BOGARD, DD (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,CODE SN4,HOUSTON,TX 77058, USA. RI Klein, Jeffrey/E-3295-2013 NR 68 TC 49 Z9 49 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAY 25 PY 1995 VL 100 IS E5 BP 9401 EP 9416 DI 10.1029/95JE00663 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RA507 UT WOS:A1995RA50700003 ER PT J AU CAPLAN, ML STOAKLEY, DM STCLAIR, AK AF CAPLAN, ML STOAKLEY, DM STCLAIR, AK TI SYNTHESIS AND CHARACTERIZATION OF SELF-METALLIZING GOLD-DOPED POLYIMIDE FILMS SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article ID SPECTROSCOPY; ADHESION; SURFACES; COPPER; METAL AB State-of-the-art methods for producing reflective polymer films for space applications involve multiple steps, and the integrity of the metal-polymer interface is less than optimal. A more efficient; process was developed that consists of doping polyamic acid resins with gold additives and curing them to form self-metallizing polyimide films. Several moderately reflective, flexible metallic gold films were produced that have good thermal stability and mechanical properties, a strong metal-polymer interface, and in some cases, electrical conductivity. It was found that; the polymer system, gold additive, gold concentration, and heat treatment all affect the reflectivity, flexibility, and conductivity of the resulting polyimide films by affecting the degree of metallization of the film surface. (C) 1995 John Wiley and Sons, Inc. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. NR 25 TC 8 Z9 8 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD MAY 23 PY 1995 VL 56 IS 8 BP 995 EP 1006 DI 10.1002/app.1995.070560813 PG 12 WC Polymer Science SC Polymer Science GA QV954 UT WOS:A1995QV95400013 ER PT J AU KALSHOVEN, JE TIERNEY, MR DAUGHTRY, CST MCMURTREY, JE AF KALSHOVEN, JE TIERNEY, MR DAUGHTRY, CST MCMURTREY, JE TI REMOTE-SENSING OF CROP PARAMETERS WITH A POLARIZED, FREQUENCY-DOUBLED ND-YAG LASER SO APPLIED OPTICS LA English DT Article DE LASER; LASER APPLICATIONS; REMOTE SENSING; POLARIZATION; MULTISPECTRAL; NORMALIZED DIFFERENCE VEGETATION INDEX; LEAF AREA INDEX; CROP YIELD; PLANT STRESS; AGRICULTURE; LIDAR AB Polarized laser remote-sensing measurements that correlate the yield, the normalized difference vegetation index, and the leaf area index with the depolarized backscattered radiation from corn plots grown with eight different nitrogen fertilization dosages are presented. A polarized Nd:YAG laser emitting at 1064 and 532 nm is used. Depolarization increased significantly with increasing fertilization at the infrared wavelength, and there was a decrease in the depolarization at the green wavelength. The depolarization spectral difference index, defined as the absolute difference in the depolarization at the two wavelengths, is introduced as a parameter that is an indicator of the condition of the internal leaf structure. C1 USDA ARS,REMOTE RES LAB,BELTSVILLE,MD 20705. RP KALSHOVEN, JE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771, USA. NR 7 TC 10 Z9 10 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1995 VL 34 IS 15 BP 2745 EP 2749 PG 5 WC Optics SC Optics GA QZ042 UT WOS:A1995QZ04200021 PM 21052420 ER PT J AU BUCHOLTZ, A AF BUCHOLTZ, A TI RAYLEIGH-SCATTERING CALCULATIONS FOR THE TERRESTRIAL ATMOSPHERE SO APPLIED OPTICS LA English DT Article DE RAYLEIGH SCATTERING; RAYLEIGH OPTICAL DEPTH; RAYLEIGH CROSS SECTION ID AIR AB Rayleigh-scattering cross sections and volume-scattering coefficients are computed for standard air; they incorporate the variation of the depolarization factor with wavelength. Rayleigh optical depths are then calculated for the 1962 U.S. Standard Atmosphere and for five supplementary models. Analytic formulas are derived for each of the parameters listed. The new optical depths can be 1.3% lower to 3% higher at midvisible wavelengths and up to 10% higher in the UV region compared with previous calculations, in which a constant or incorrect depolarization factor was used. The dispersion of the depolarization factor is also shown to affect the Rayleigh phase function slightly, by approximately 1% in the forward, backscattered, and 90 degrees scattering-angle directions. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 25 TC 301 Z9 307 U1 5 U2 34 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1995 VL 34 IS 15 BP 2765 EP 2773 PG 9 WC Optics SC Optics GA QZ042 UT WOS:A1995QZ04200024 PM 21052423 ER PT J AU SILVER, JA KANE, DJ GREENBERG, PS AF SILVER, JA KANE, DJ GREENBERG, PS TI QUANTITATIVE SPECIES MEASUREMENTS IN MICROGRAVITY FLAMES WITH NEAR-IR DIODE-LASERS SO APPLIED OPTICS LA English DT Article DE MICROGRAVITY; COMBUSTION; DIODE LASER; WAVELENGTH MODULATION SPECTROSCOPY ID FREQUENCY-MODULATION SPECTROSCOPY; JET DIFFUSION FLAMES; TEMPERATURE AB Absolute concentrations of water vapor are measured in microgravity (mu-g), nonpremixed methane, and propane jet flames with diode-laser wavelength modulation spectroscopy. These experiments are performed in the 2.2-s mu-g drop facility at the NASA Lewis Research Center. Abel inversion methods are used to determine time-dependent radial profiles from eight line-of-sight projections across the flames. At all measured heights above the nozzle, water vapor spatial distributions in mu-g flames are much wider than their 1-g counterparts. Radial growth of the water signal continues throughout the drop, verifying earlier suggestions that a steady state is not reached during the duration of the test, despite a quasi-steady flame shape. Large amounts of water vapor are observed at larger radii, at odds with visual (video) observations and numerical predictions. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SILVER, JA (reprint author), SW SCI INC,1570 PACHECO ST,SUITE E-11,SANTA FE,NM 87505, USA. NR 21 TC 43 Z9 45 U1 2 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 1995 VL 34 IS 15 BP 2787 EP 2801 PG 15 WC Optics SC Optics GA QZ042 UT WOS:A1995QZ04200027 PM 21052426 ER PT J AU MUKHERJEE, R ALLER, HD ALLER, MF BERTSCH, DL COLLMAR, W DIGEL, SW DINGUS, BL ESPOSITO, JA FICHTEL, CE HARTMAN, RC HUNTER, SD JOHNSON, WN KANBACH, G KNIFFEN, DA LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL RAMANAMURTHY, PV SCHNEID, E SREEKUMAR, P TERASRANTA, H THOMPSON, DJ WAGNER, SJ AF MUKHERJEE, R ALLER, HD ALLER, MF BERTSCH, DL COLLMAR, W DIGEL, SW DINGUS, BL ESPOSITO, JA FICHTEL, CE HARTMAN, RC HUNTER, SD JOHNSON, WN KANBACH, G KNIFFEN, DA LIN, YC MATTOX, JR MAYERHASSELWANDER, HA MICHELSON, PF VONMONTIGNY, C NOLAN, PL RAMANAMURTHY, PV SCHNEID, E SREEKUMAR, P TERASRANTA, H THOMPSON, DJ WAGNER, SJ TI EGRET GAMMA-RAY SOURCES - GRO-JO744+54 AND GRO-JO957+65 (=BL-LACERTAE OBJECT-0954+658) SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL LACERTAE OBJECTS, INDIVIDUAL (0954+ 658); GAMMA RAYS, OBSERVATIONS ID TELESCOPE; VARIABILITY; 3C-279 AB EGRET detected an unidentified source, GRO J0744+54, at a significance of 6.5 sigma, during its observations from 1993 June 28 to July 12. The source was seen again in the following 2 week viewing period and was weakly evident in the earlier phase 1 of the EGRET observations. Considering the variability of its gamma-ray flux, and its location at high Galactic latitude, GRO J0744+54 is likely to be a previously undetected blazar. Its most likely identification is with the radio source 87GB 073840.5+545138. A second source, GRO J0957+65, was seen by EGRET during the same two viewing periods at a combined significance of 5.7 sigma. The most probable counterpart of GRO J0957+65 is the BL Lacertae object 0954+658. The spectra, time variability, and positions of the two sources are presented. Multiwavelength observations of 0954+658 are also presented. C1 UNIV SPACE RES ASSOC,WASHINGTON,DC. UNIV MICHIGAN,DEPT ASTRON,ANN ARBOR,MI 48109. MAX PLANCK INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. HARVARD SMITHSONIAN CTR ASTRON,CAMBRIDGE,MA 02138. USN,RES LAB,WASHINGTON,DC 20375. HAMPDEN SYDNEY COLL,HAMPDEN SYDNEY,VA 23943. STANFORD UNIV,WW HANSEN EXPTL PHYS LAB,STANFORD,CA 94305. GRUMMAN AEROSP CORP,BETHPAGE,NY 11714. METSAHOVI RADIO RES STN,SF-02540 KYLMALA,FINLAND. LANDESSTERNWARTE KONIGSTUHL,D-69117 HEIDELBERG,GERMANY. RP MUKHERJEE, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. RI Nolan, Patrick/A-5582-2009; Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; Johnson, Neil/G-3309-2014; OI Thompson, David/0000-0001-5217-9135; Dingus, Brenda/0000-0001-8451-7450 NR 31 TC 25 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1995 VL 445 IS 1 BP 189 EP 195 DI 10.1086/175685 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY129 UT WOS:A1995QY12900020 ER PT J AU HURLEY, K LI, P LAROS, J FISHMAN, G KOUVELIOTOU, C MEEGAN, C AF HURLEY, K LI, P LAROS, J FISHMAN, G KOUVELIOTOU, C MEEGAN, C TI THE FIRST SEARCH FOR A GAMMA-RAY BURST QUIESCENT COUNTERPART IN THE EXTREME-ULTRAVIOLET WITH EUVE SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA RAYS, BURSTS; STARS, NEUTRON; ULTRAVIOLET, GENERAL ID NEUTRON-STAR MODELS; ERROR BOXES; CONSTRAINTS; RADIO; BATSE AB The opening of the extreme ultraviolet window by the EUVE satellite has provided the unique opportunity to perform the first search for a quiescent gamma-ray burst counterpart at these wavelengths. Such emission might be expected if some bursts are related to nearby hot neutron stars or neutron stars with accretion disks, among other objects. We report here on a 40 ks observation on the 1992 March 25 gamma-ray burst error box, determined by triangulation with the Third Interplanetary Network. No quiescent 40-190 Angstrom EUV source was identified using the Deep Survey instrument, and a 3 sigma upper limit of 2.9 x 10(-14) erg cm(-2) s(-1) was obtained. Similarly, upper limits to the 140-380 and 280-760 Angstrom fluxes were obtained with the medium- and long-wavelength spectrometers; they are 1.1 x 10(-12) and 5.0 x 10(-13) erg cm(-2) s(-1), respectively. We discuss the constraints which these limits impose on thermally radiating quiescent counterparts. C1 UNIV ARIZONA,DEPT PLANETARY SCI,TUCSON,AZ 85721. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP HURLEY, K (reprint author), UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720, USA. NR 33 TC 5 Z9 5 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1995 VL 445 IS 1 BP 348 EP 350 DI 10.1086/175699 PN 1 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY129 UT WOS:A1995QY12900034 ER PT J AU BRAGE, T FISCHER, CF JUDGE, PG AF BRAGE, T FISCHER, CF JUDGE, PG TI TRANSITION-PROBABILITIES FOR THE UVO.O1 MULTIPLET IN N-III SO ASTROPHYSICAL JOURNAL LA English DT Article DE ATOMIC DATA; STARS, INDIVIDUAL (RR TELESCOPII, V1016 CYGNI); ULTRAVIOLET, GENERAL; ULTRAVIOLET, STARS ID ULTRAVIOLET LINES; DIAGNOSTICS; SPECTRUM; LIMB; IV AB We report on large-scale ah initio multiconfiguration Hartree-Fock calculations for the UV0.01 multiplet, 2s(2)2p(2)P(J)-2s2p(2 4) P-J', in N III. The resulting transition probabilities agree very well with recent semiempirical calculations, and the lifetimes for two of the three upper levels agree with experiments. The deviation for the third level is discussed. Comparisons made with the highest quality IUE echelle spectra available-those of RR Tel and V1016 Cyg (both photoionized sources with electron densities below 10(8) cm(-3)-show that computed branching ratios of lines sharing a common upper level are in agreement with observations to within uncertainties of +/-10%. High-quality solar limb data or stellar data from the Hubble Space Telescope could, in principle, be used to determine whether the theoretical or measured lifetimes for the discrepant level are in error. Unfortunately, stellar data for high-density plasmas (N-e > 10(11) cm(-3) are needed) do not yet exist, and existing solar data lack the photometric precision to address this problem. C1 VANDERBILT UNIV,DEPT COMP SCI,NASHVILLE,TN 37235. NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. RP BRAGE, T (reprint author), NRC,GODDARD SPACE FLIGHT CTR,CODE 681,GREENBELT,MD 20771, USA. OI Brage, Tomas/0000-0003-3985-767X NR 30 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 1995 VL 445 IS 1 BP 457 EP 464 DI 10.1086/175710 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY129 UT WOS:A1995QY12900045 ER PT J AU MORIARTYSCHIEVEN, GH BUTNER, HM WANNIER, PG AF MORIARTYSCHIEVEN, GH BUTNER, HM WANNIER, PG TI THE L1551NE MOLECULAR OUTFLOW SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, INDIVIDUAL (L1551NE); ISM, JETS AND OUTFLOWS; ISM, MOLECULES; STARS, FORMATION ID CLOUDS AB L1551NE is a very young protostar (class I or perhaps class 0), located very close to L1551 IRS 5. It is the second brightest far-infrared source in the Taurus molecular cloud complex, but its proximity to the brightest source IRS 5 has prevented effective observations of any molecular outflow. We here present evidence that it does indeed possess an outflow, that the optical/infrared reflection nebula is associated with the blueshifted outflow lobe, and that the L1551W outflow does not originate from L1551NE, as has been suggested. C1 CARNEGIE INST WASHINGTON,DEPT TERR MAGNETISM,WASHINGTON,DC 20015. JET PROPULS LAB,PASADENA,CA 91109. RP MORIARTYSCHIEVEN, GH (reprint author), NATL RES COUNCIL CANADA,DOMINION RADIO ASTROPHYS OBSERV,BOX 248,PENTICTON,BC V2A 6K3,CANADA. NR 19 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 MAY 20 PY 1995 VL 445 IS 1 BP L55 EP L58 DI 10.1086/187888 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY132 UT WOS:A1995QY13200014 ER PT J AU GUENTHER, A HEWITT, CN ERICKSON, D FALL, R GERON, C GRAEDEL, T HARLEY, P KLINGER, L LERDAU, M MCKAY, WA PIERCE, T SCHOLES, B STEINBRECHER, R TALLAMRAJU, R TAYLOR, J ZIMMERMAN, P AF GUENTHER, A HEWITT, CN ERICKSON, D FALL, R GERON, C GRAEDEL, T HARLEY, P KLINGER, L LERDAU, M MCKAY, WA PIERCE, T SCHOLES, B STEINBRECHER, R TALLAMRAJU, R TAYLOR, J ZIMMERMAN, P TI A GLOBAL-MODEL OF NATURAL VOLATILE ORGANIC-COMPOUND EMISSIONS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIOGENIC HYDROCARBON EMISSIONS; CALIFORNIA CENTRAL VALLEY; ISOPRENE EMISSION; ATMOSPHERIC HYDROCARBONS; RATE VARIABILITY; CARBON-MONOXIDE; BOUNDARY-LAYER; CLIMATE-CHANGE; GAS-EXCHANGE; WATER-STRESS AB Numerical assessments of global air quality and potential changes in atmospheric chemical constituents require estimates of the surface fluxes of a variety of trace gas species. We have developed a global model to estimate emissions of volatile organic compounds from natural sources (NVOC). Methane is not considered here and has been reviewed in detail elsewhere. The model has a highly resolved spatial grid (0.5 degrees x 0.5 degrees latitude/longitude) and generates hourly average emission estimates. Chemical species are grouped into four categories: isoprene, monoterpenes, other reactive VOC (ORVOC), and other VOC (OVOC). NVOC emissions from oceans are estimated as a function of geophysical variables from a general circulation model and ocean color satellite data. Emissions from plant foliage are estimated from ecosystem specific biomass and emission factors and algorithms describing light and temperature dependence of NVOC emissions. Foliar density estimates are based on climatic variables and satellite data. Temporal variations in the model are driven by monthly estimates of biomass and temperature and hourly light estimates. The annual global VOC flux is estimated to be 1150 Tg C, composed of 44% isoprene, 11% monoterpenes, 22.5% other reactive VOC, and 22.5% other VOC. Large uncertainties exist for each of these estimates and particularly for compounds other than isoprene and monoterpenes. Tropical woodlands (rain forest, seasonal, drought-deciduous, and savanna) contribute about half of all global natural VOC emissions. Croplands, shrublands and other woodlands contribute 10-20% apiece. Isoprene emissions calculated for temperate regions are as much as a factor of 5 higher than previous estimates. C1 UNIV COLORADO, COOPERAT INST RES ENVIRONM SCI, BOULDER, CO 80309 USA. US EPA, AIR & ENERGY ENGN RES LAB, RES TRIANGLE PK, NC 27711 USA. AT&T BELL LABS, MURRAY HILL, NJ 07974 USA. UNIV LANCASTER, INST ENVIRONM & BIOL SCI, LANCASTER LA1 4YQ, ENGLAND. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. HARWELL LAB, HARWELL 110RA, OXON, ENGLAND. US EPA, ATMOSPHER RES & EXPOSURE LAB, RES TRIANGLE PK, NC 27711 USA. DIV FOREST SCI & TECHNOL, PRETORIA 0001, SOUTH AFRICA. INST ATMOSPHAR UMWELT, W-1800 GARMISCH PARTENKIRCHEN, GERMANY. AUSTRALIAN NATL UNIV, CANBERRA, ACT 2601, AUSTRALIA. UNIV COLORADO, DEPT CHEM & BIOCHEM, BOULDER, CO 80309 USA. RP GUENTHER, A (reprint author), NATL CTR ATMOSPHER RES, 1850 TABLE MESA DR, BOULDER, CO 80303 USA. RI Hewitt, Charles Nicholas/B-1219-2009; Taylor, John/E-5894-2010; Steinbrecher, Rainer/A-7414-2013; Lerdau, Manuel/E-7320-2011; Garmisch-Pa, Ifu/H-9902-2014; Guenther, Alex/B-1617-2008 OI Hewitt, Charles Nicholas/0000-0001-7973-2666; Taylor, John/0000-0001-9003-4076; Lerdau, Manuel/0000-0003-1864-0834; Guenther, Alex/0000-0001-6283-8288 NR 93 TC 2302 Z9 2406 U1 71 U2 601 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 8873 EP 8892 DI 10.1029/94JD02950 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400003 ER PT J AU CHAHINE, MT AF CHAHINE, MT TI OBSERVATION OF LOCAL CLOUD AND MOISTURE FEEDBACKS OVER HIGH OCEAN AND DESERT SURFACE TEMPERATURES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DEEP CONVECTION; SATELLITE DATA; CLIMATE; PARAMETERS; RETRIEVAL; HIRS2/MSU; DROUGHT; ALBEDO AB New data on clouds and moisture, made possible by reanalysis of weather satellite observations, show that the atmosphere reacts to warm clusters of very high sea surface temperatures in the western Pacific Ocean with increased moisture, cloudiness, and convection, suggesting a negative feedback limiting the sea surface temperature rise. The reverse was observed over dry and hot deserts where both moisture and cloudiness decrease, suggesting a positive feedback perpetuating existing desert conditions. In addition, the observations show a common critical surface temperature for both oceans and land; the distribution of atmospheric moisture is observed to reach a maximum value when the daily surface temperatures approach 304 +/- 1 K. These observations reveal complex dynamic-radiative interactions where multiple processes act simultaneously at the surface as well as in the atmosphere to regulate the feedback processes. RP CHAHINE, MT (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MAIL CODE 180-904, PASADENA, CA 91109 USA. NR 36 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 8919 EP 8927 DI 10.1029/95JD00094 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400005 ER PT J AU STEWART, RW AF STEWART, RW TI DYNAMICS OF THE LOW TO HIGH NOX TRANSITION IN A SIMPLIFIED TROPOSPHERIC PHOTOCHEMICAL MODEL SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STEADY-STATES; DEPENDENCE AB A simplified photochemical model designed to capture the basic properties tropospheric O-x, HOx, NOx, CO, CH4 system is used to study the transition between low and high NOx conditions. These regimes are characterized by substantially different chemical properties and by the existence of a single, stable steady state for each parameter set consistent with low or high NOx conditions. In the parameter space of the system, low and high NOx conditions are separated by a transition zone which corresponds to multiple and/or unstable solutions in the state space of the system. This paper discusses a number of different transitions between low and high NOx conditions which occur as NO and CO source strengths are varied. Emphasis is on the consequences of the existence of a region in parameter space which corresponds to unstable steady states and stable limit cycles in state space. These limit cycles are oscillatory solutions with periods ranging from hundreds to thousands of years. They consist of low and high NOx phases of relatively slowly varying composition separated by transitions in which rapid changes in composition occur. The: characteristics of these phases are described in terms of an ozone production cycle based on the chemical reactions assumed to take place. Depending on the phase of the limit cycle, ozone may accelerate or inhibit its own production. The former case represents an autocatalytic cycle with possible ''runaway'' growth of oxidants. The transition between low and high NOx conditions is described with the aid of an ''autocatalytic ratio'' defined in the text. RP STEWART, RW (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 916, GREENBELT, MD 20771 USA. NR 19 TC 35 Z9 35 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 MAY 20 PY 1995 VL 100 IS D5 BP 8929 EP 8943 DI 10.1029/95JD00691 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400006 ER PT J AU VEIGA, RE CUNNOLD, DM CHU, WP MCCORMICK, MP AF VEIGA, RE CUNNOLD, DM CHU, WP MCCORMICK, MP TI STRATOSPHERIC AEROSOL AND GAS EXPERIMENT-I AND EXPERIMENT-II COMPARISONS WITH OZONESONDES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SAGE-II; OZONE MEASUREMENTS; SATELLITE; PROFILES; VALIDATION; INVERSION AB Ozone profiles measured by the Stratospheric Aerosol and Gas Experiments (SAGE)I and II are compared with ozonesonde profiles at 24 stations over the period extending from 1979 through 1991. Ozonesonde/satellite differences at 21 stations with SAGE II overpasses were computed down to 11.5 km in the midlatitudes, to 15.5 km in the lower latitudes, and for nine stations with SAGE I overpasses down to 15.5 km. The set of individual satellite and ozonesonde profile comparisons most closely colocated in time and space shows mean absolute differences relative to the satellite measurement of 6 +/- 2% for SAGE II and 8 +/- 3% for SAGE I. The ensemble of ozonesonde/satellite differences, when averaged over all altitudes, shows that for SAGE II, 70% were less than 5%, whereas for SAGE I, 50% were less than 5%. The best agreement occurred in the altitude region near the ozone density maximum where almost all the relative differences were less than 5%. Most of the statistically significant differences occurred below the ozone maximum down to the tropopause in the region of steepest ozone gradients and typically ranged between 0 and -20%. Correlations between ozone and aerosol extinction in the northern midlatitudes indicate that aerosols had no discernible impact on the ozonesonde/satellite differences and on the SAGE II ozone retrieval for the levels of extinction encountered in the lower stratosphere during 1984 to mid-1991. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. GEORGIA INST TECHNOL, SCH EARTH & ATMOSPHER SCI, ATLANTA, GA 30332 USA. RP VEIGA, RE (reprint author), SCI APPLICAT INT CORP, 1 ENTERPRISE PKWY, SUITE 250, HAMPTON, VA 23666 USA. NR 42 TC 27 Z9 28 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 MAY 20 PY 1995 VL 100 IS D5 BP 9073 EP 9090 DI 10.1029/94JD03251 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400015 ER PT J AU MARGITAN, JJ BARNES, RA BROTHERS, GB BUTLER, J BURRIS, J CONNOR, BJ FERRARE, RA KERR, JB KOMHYR, WD MCCORMICK, MP MCDERMID, IS MCELROY, CT MCGEE, TJ MILLER, AJ OWENS, M PARRISH, AD PARSONS, CL TORRES, AL TSOU, JJ WALSH, TD WHITEMAN, D AF MARGITAN, JJ BARNES, RA BROTHERS, GB BUTLER, J BURRIS, J CONNOR, BJ FERRARE, RA KERR, JB KOMHYR, WD MCCORMICK, MP MCDERMID, IS MCELROY, CT MCGEE, TJ MILLER, AJ OWENS, M PARRISH, AD PARSONS, CL TORRES, AL TSOU, JJ WALSH, TD WHITEMAN, D TI STRATOSPHERIC OZONE INTERCOMPARISON CAMPAIGN (STOIC) 1989 - OVERVIEW SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The NASA Upper Atmosphere Research Program organized a Stratospheric Ozone Intercomparison Campaign (STOIC) held in July-August 1989 at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL). The primary instruments participating in this campaign were several that had been developed by NASA for the Network for the Detection of Stratospheric Change: the JPL ozone lidar at TMF, the Goddard Space Flight Center trailer-mounted ozone lidar which was moved to TMF for this comparison, and the Millitech/LaRC microwave radiometer, To assess the performance of these new instruments, a validation/intercomparison campaign was undertaken using established techniques: balloon ozonesondes launched by personnel from the Wallops Flight Facility and from NOAA Geophysical Monitoring for Climate Change (GMCC) (now Climate Monitoring and Diagnostics Laboratory), a NOAA GMCC Dobson spectrophotometer, and a Brewer spectrometer from the Atmospheric Environment Service of Canada, both being used for column as well as Umkehr profile retrievals. All of these instruments were located at TMF and measurements were made as close together in time as possible to minimize atmospheric variability as a factor in the comparisons, Daytime rocket measurements of ozone were made by Wallops Flight Facility personnel using ROCOZ-A instruments launched from San Nicholas Island. The entire campaign was conducted as a blind intercomparison, with the investigators not seeing each others data until all data had been submitted to a referee and archived at the end of the 2-week period (July 20 to August 2, 1989). Satellite data were also obtained from the Stratospheric Aerosol and Gas Experiment (SAGE EI) aboard the Earth Radiation Budget Satellite and the total ozone mapping spectrometer (TOMS) aboard Nimbus 7. An examination of the data has found excellent agreement among the techniques, especially in the 20- to 40-km range. As expected, there was little atmospheric variability during the intercomparison, allowing for detailed statistical comparisons at a high level of precision. This overview paper will summarize the campaign and provide a ''road map'' to subsequent papers in this issue by the individual instrument teams which will present more detailed analysis of the data and conclusions. C1 CHEMAL INC, WALLOPS ISL, VA USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. HUGHES STX CORP, LANHAM, MD 20706 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA. ATMOSPHER ENVIRONM SERV, DOWNSVIEW, ON M3H 5T4, CANADA. NOAA, CTR CLIMATE ANAL, WASHINGTON, DC 20233 USA. UNIV MARYLAND, DEPT PHYS, COLLEGE PK, MD 20742 USA. UNIV MASSACHUSETTS, DEPT PHYS & ASTRON, AMHERST, MA 01003 USA. NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA 23337 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23666 USA. NASA, GODDARD SPACE FLIGHT CTR, TERR PHYS LAB, GREENBELT, MD 20771 USA. RP MARGITAN, JJ (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. RI McGee, Thomas/G-4951-2013; Butler, James/D-4188-2013 NR 37 TC 31 Z9 31 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 9193 EP 9207 DI 10.1029/95JD00509 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400023 ER PT J AU BARNES, RA PARSONS, CL GROTHOUSE, AP AF BARNES, RA PARSONS, CL GROTHOUSE, AP TI ROCOZ-A OZONE MEASUREMENTS DURING THE STRATOSPHERIC OZONE INTERCOMPARISON CAMPAIGN (STOIC) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GAS EXPERIMENT-II; PROFILES; MESOSPHERE; AEROSOL AB We present a set of ROCOZ-A (rocket ozonesonde) ozone measurements during the October/November 1988 (pre-STOIC) and the July/August 1989 Stratospheric Ozone Intercomparison Campaign (STOIC) in southern California. ROCOZ-A and its associated electrochemical concentration eel (ECC) ozonesondes participated in the comparisons as established techniques for the validation of lidar and microwave instruments that have been proposed for the Network for the Detection of Stratospheric Change (NDSC). For the proposed network instruments, STOIC has provided a picture of their performance characteristics in 1989 and has given an estimate of their future performance in the NDSC. For ROCOZ-A, STOIC has added new information on its accuracy and precision. It is this continuing characterization that gives ROCOZ-A its value in comparisons. The STOIC comparisons show a shift of 5-6% in ROCOZ-A ozone densities (ROCOZ-A higher) from October/November 1988 to July/August 1989. This shift has been seen in comparisons with the Stratospheric Aerosol and Gas Experiment II (SAGE II), ECC ozonesondes, and the Jet Propulsion Laboratory (JPL) lidar. The source of this shift has not been determined. Until this new error source is resolved, we recommend that the previously quoted accuracy estimate for ROCOZ-A ozone measurements be increased from 5-7% to 8-10%. About 2% of the difference between ROCOZ-A ozone measurements and those from the proposed network instruments in 1989 appears to be due to differences in atmospheric ozone between the two STOIC sites. A correction for these site-to-site differences brings the ROCOZ-A ozone measurements within 10% of all of the other STOIC instruments, and the average agreement (ROCOZ-A 6% higher) becomes consistent with the historical set of ROCOZ-A comparisons. The STOIC comparisons have shown structures in stratospheric ozone that cannot be resolved by ROCOZ-A with its 4-km vertical resolution. In addition, comparisons with nighttime measurements from the Millitech microwave above 45 km show a divergence from the daytime ROCOZ-A values that agrees with the general characteristics of the diurnal cycle in upper stratospheric ozone that is predicted by photochemical models. Evidence of this ozone cycle is also seen in ROCOZ-A comparisons with the SAGE IT zonal mean above 45 km but not in comparisons with the nighttime measurements from the JPL lidar. The effects of diurnal ozone change in the upper stratosphere and mesosphere will be an important consideration in future comparisons of NDSC instruments. C1 COMP SCI CORP, WALLOPS ISL, VA 23337 USA. NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA 23337 USA. RP BARNES, RA (reprint author), MANTECH INC, BLDG F-160, WALLOPS ISL, VA 23337 USA. NR 29 TC 4 Z9 4 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 MAY 20 PY 1995 VL 100 IS D5 BP 9209 EP 9223 DI 10.1029/94JD03126 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400024 ER PT J AU BARNES, RA TORRES, AL AF BARNES, RA TORRES, AL TI ELECTROCHEMICAL CONCENTRATION CELL OZONE SOUNDINGS AT 2 SITES DURING THE STRATOSPHERIC OZONE INTERCOMPARISON CAMPAIGN SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The Stratospheric Ozone Intercomparison Campaign (STOIC) was designed to compare proposed instruments for the Network for the Detection of Stratospheric Change (NDSC) with established measurement techniques. Ground-based measurements were conducted at Table Mountain, California (34.4 degrees N, 117.7 degrees W), and rocket profiles were made at San Nicolas Island, California (33.3 degrees N, 119.5 degrees W). In an effort to estimate site-to-site differences during the intercomparison, daily soundings were made with balloon-borne electrochemical concentration cell (ECC) ozonesondes at the two sites.;Comparisons have been made of the mean values for the soundings at each site. The soundings showed small temperature differences between the two sites with the nighttime Table Mountain measurements up to 2 degrees K cooler than the daytime San Nicolas Island temperatures, Day/night temperature corrections based on the emissivity and absorptivity of the thermistors in the balloon instruments can account for these apparent temperature differences. Ozone partial pressure profiles from the ECCs have been used to estimate atmospheric ozone variability during STOIC. Above 20 km, the lowest altitude for the STOIC comparisons, the average data sets from both sites showed standard deviations that were at or below the estimated 5-6% profile-to-profile repeatability for the ozonesondes. This indicates that atmospheric ozone variability was only of the order of a few percent above 20 km during the 2 weeks of the STOIC campaign. Above 20 km the ozone partial pressures over the Table Mountain site averaged 2.0% lower than over San Nicolas Island. C1 NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, WALLOPS ISL, VA 23337 USA. RP BARNES, RA (reprint author), MANTECH INC, BLDG F-160, WALLOPS ISL, VA 23337 USA. NR 25 TC 5 Z9 5 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 MAY 20 PY 1995 VL 100 IS D5 BP 9245 EP 9253 DI 10.1029/94JD02522 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400027 ER PT J AU MCGEE, TJ FERRARE, RA WHITEMAN, DN BUTLER, JJ BURRIS, JF OWENS, MA AF MCGEE, TJ FERRARE, RA WHITEMAN, DN BUTLER, JJ BURRIS, JF OWENS, MA TI LIDAR MEASUREMENTS OF STRATOSPHERIC OZONE DURING THE STOIC CAMPAIGN SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB The NASA Goddard Space Flight Center's Stratospheric Ozone Lidar Trailer Experiment participated in the Stratospheric Ozone Intercomparison Campaign (STOIC) at Table Mountain, California, from July 20 to August 2, 1989. From 20 to 39 km the average Goddard Space Flight Center (GSFC) profile agreed with the STOIC reference profile to better than 5%. The STOIC reference profile was generated by averaging all profiles from the eight participating instruments. In this same altitude region the GSFC and the Jet Propulsion Laboratory lidar average profiles also agreed to better than 5%. Similar results were found for an intercomparison of the lidar data with ozone data from ECC sondes launched from Table Mountain and from San Nicholas Island. The results of the intercomparison have led to a number of modifications to the GSFC lidar which have greatly improved the reliability of the ozone data, particularly at altitudes below 20 km and above 40 km. C1 NASA, GODDARD SPACE FLIGHT CTR, TERR PHYS LAB, GREENBELT, MD 20771 USA. ST SYST CORP, LANHAM, MD 20706 USA. UNIV MARYLAND, DEPT ELECT ENGN, COLLEGE PK, MD 20742 USA. RP MCGEE, TJ (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, MAIL CODE 915, GREENBELT, MD 20771 USA. RI McGee, Thomas/G-4951-2013; Butler, James/D-4188-2013 NR 10 TC 11 Z9 11 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 9255 EP 9262 DI 10.1029/94JD02390 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400028 ER PT J AU MCDERMID, IS GODIN, SM WALSH, TD AF MCDERMID, IS GODIN, SM WALSH, TD TI RESULTS FROM THE JET-PROPULSION-LABORATORY STRATOSPHERIC OZONE LIDAR DURING STOIC 1989 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TABLE MOUNTAIN; 34.4-DEGREES-N; AEROSOL AB Stratospheric ozone concentration profiles measured by the Jet Propulsion Laboratory differential absorption lidar system during the Stratospheric Ozone Intercomparison Campaign in July/August 1989 are presented. These profiles are compared with the mean profiles based on all of the measurements made by the different participating instruments. The results from the blind intercomparison showed that the lidar results agreed with the overall Stratospheric Ozone Intercomparison Campaign average profile to better than 5% between 21 and 45 km altitude. At 20 km the difference was similar to 10%, as it was also in the region from 47 to 50 km altitude. Some systematic features were observed in the comparison of the blind results and these were subsequently investigated. The results of this investigation allowed the analysis algorithm to be refined and improved, The changes made are discussed and the comparison of the refined results showed agreement with the STOIC average to better than 4% from 18 to 48 km altitude. For both cases the results above 45 km altitude are subject to the greatest uncertainty and error and are of questionable value even though they agree within 10% with the STOIC average. Examples of comparisons of individual lidar profiles with each of the other instruments are also presented. RP MCDERMID, IS (reprint author), CALTECH, JET PROP LAB, TABLE MT FACIL, POB 367, WRIGHTWOOD, CA 92397 USA. NR 23 TC 10 Z9 10 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 9263 EP 9272 DI 10.1029/94JD02148 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400029 ER PT J AU KOMHYR, WD CONNOR, BJ MCDERMID, IS MCGEE, TJ PARRISH, AD MARGITAN, JJ AF KOMHYR, WD CONNOR, BJ MCDERMID, IS MCGEE, TJ PARRISH, AD MARGITAN, JJ TI COMPARISON OF STOIC 1989 GROUND-BASED LIDAR, MICROWAVE SPECTROMETER, AND DOBSON SPECTROPHOTOMETER UMKEHR OZONE PROFILES WITH OZONE PROFILES FROM BALLOON-BORNE ELECTROCHEMICAL CONCENTRATION CELL OZONESONDES SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB Ground-based measurements of stratospheric ozone using a Jet Propulsion Laboratory (JPL) lidar, a NASA Goddard Space Flight Center (GSFC) lidar, a Millitech Corporation/NASA Langley Research Center (Millitech/LaRC) microwave spectrometer, and a NOAA Dobson ozone spectrophotometer were compared with in situ measurements made quasi-simultaneously with balloon-borne electrochemical concentration cell (ECC) ozonesondes during 10 days of the Stratospheric Ozone Intercomparison Campaign (STOIC). The campaign was conducted at Table Mountain Observatory, California, during the summer of 1989. ECC ozonesondes were flown by NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) personnel as well as by personnel from the NASA Wallops Island Flight Facility (WFF). Within the altitude range of 20-32 km, ozone measurement precisions were estimated to be +/-0.6 to +/-1.2% for the JPL lidar, +/-0.7% for the GSFC lidar, +/-4% for the microwave spectrometer, and +/-3% for the NOAA ECC ozonesonde instruments. These precisions decreased in the 32 to 38.6-km altitude range to +/-1.3, +/-1.5, and +/-3% to +/-10% for the JPL lidar, GSFC lidar, and the ECC sondes, respectively, but remained at +/-4% for the microwave instrument. Ozone measurement accuracies in the 20 to 32 km altitude range were estimated to be +/-1.2 to +/-2.4% for the JPL lidar, +/-1.4% for the GSFC lidar, +/-6% for the microwave radiometer, and +/-5% for the ECC ozonesondes. The accuracies decreased in the 32 to 38.6-km altitude range to +/-2.6, +/-3.0, +/-7, and 1 +/-4% to -4 +/- 10% for the JPL lidar, the GSFC lidar, the microwave spectrometer, and the ECC ozonesondes, respectively. While accuracy estimates for the ECC sondes were obtained by combining random and estimated bias errors, the accuracies for the lidar instruments were obtained by doubling the measurement precision figures, with the assumption that such doubling accounts for systematic errors. Within the altitude range of 20-36 km the mean ozone profiles produced by the JPL, GSFC, and the Millitech/LaRC groups did not differ from the mean ECC sonde ozone profile by more than about 2, 4, and 5%, respectively, Six morning Dobson instrument Umkehr observations yielded mean ozone amounts in layers 3 and 5-7 that agreed with comparison ECC ozonesonde data to within +/-4%. In layer 4 the difference was 7.8%, (Less favorable comparison data were obtained for six afternoon Umkehr observations made in highly polluted near-surface air.) This good agreement in overall results obtained lends credence to the reliability of the ozone measurements made at Table Mountain Observatory during STOIC 1989. C1 NOAA, CLIMATE MONITORING & DIAGNOST LAB, BOULDER, CO 80303 USA. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. CALTECH, JET PROP LAB, TABLE MT FACIL, WRIGHTWOOD, CA 92397 USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. MILLITECH CORP, S DEERFIELD, MA 01373 USA. RI McGee, Thomas/G-4951-2013 NR 24 TC 13 Z9 13 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 MAY 20 PY 1995 VL 100 IS D5 BP 9273 EP 9282 DI 10.1029/94JD02173 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400030 ER PT J AU CONNOR, BJ PARRISH, A TSOU, JJ MCCORMICK, MP AF CONNOR, BJ PARRISH, A TSOU, JJ MCCORMICK, MP TI ERROR ANALYSIS FOR THE GROUND-BASED MICROWAVE OZONE MEASUREMENTS DURING STOIC SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERE; ANTARCTICA; PROFILES AB We present a formal error analysis and characterization of the microwave measurements made during the Stratospheric Ozone Intercomparison Campaign (STOIC). The most important error sources are found to be determination of the tropospheric opacity, the pressure-broadening coefficient of the observed line, and systematic variations in instrument response as a function of frequency (''baseline''). Net precision is 4-6% between 55 and 0.2 mbar, while accuracy is 6-10%. Resolution is 8-10 km below 3 mbar and increases to 17 km at 0.2 mbar. We show the ''blind'' microwave measurements from STOIC and make limited comparisons to other measurements. We use the averaging kernels of the microwave measurement to eliminate resolution and a priori effects from a comparison to SAGE II. The STOIC results and comparisons are broadly consistent with the formal analysis. C1 UNIV MASSACHUSETTS, DEPT PHYS & ASTRON, AMHERST, MA 01003 USA. LOCKHEED ENGN & SCI CO, HAMPTON, VA 23665 USA. RP CONNOR, BJ (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL STOP 401B, HAMPTON, VA 23681 USA. NR 18 TC 72 Z9 73 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 MAY 20 PY 1995 VL 100 IS D5 BP 9283 EP 9291 DI 10.1029/94JD00413 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400031 ER PT J AU MCDERMID, IS WALSH, TD AF MCDERMID, IS WALSH, TD TI SURFACE OZONE LEVELS AT TABLE MOUNTAIN DURING STOIC 1989 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB As a part of the routine operations of the Jet Propulsion Laboratory atmospheric measurements program at the Table Mountain Facility, the surface ozone concentration is continuously monitored using a Dasibi photometer. The influence of the Los Angeles basin to the southwest of the facility and the height of the inversion layer cause large fluctuations in the ozone concentration, Peaks as high as 200 parts per billion by volume (ppbv) were observed during the Stratospheric Ozone Intercomparison Campaign (STOIC) compared to a normal background level near 50 ppbv. These measurements, made during STOIC, were important in assessing the impact of the surface ozone concentration on the various instruments participating in the campaign. RP MCDERMID, IS (reprint author), CALTECH, JET PROP LAB, TABLE MT FACIL, POB 367, WRIGHTWOOD, CA 92397 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 20 PY 1995 VL 100 IS D5 BP 9301 EP 9302 DI 10.1029/94JD02302 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400033 ER PT J AU FERRARE, RA MCGEE, TJ WHITEMAN, D BURRIS, J OWENS, M BUTLER, J BARNES, RA SCHMIDLIN, F KOMHYR, W WANG, PH MCCORMICK, MP MILLER, AJ AF FERRARE, RA MCGEE, TJ WHITEMAN, D BURRIS, J OWENS, M BUTLER, J BARNES, RA SCHMIDLIN, F KOMHYR, W WANG, PH MCCORMICK, MP MILLER, AJ TI LIDAR MEASUREMENTS OF STRATOSPHERIC TEMPERATURE DURING STOIC SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE ATMOSPHERE; ROCKETSONDE; PROFILES; GRAVITY; DENSITY AB Measurements of stratospheric temperature and density were acquired by the NASA/GSFC lidar during the Stratospheric Ozone Intercomparison Campaign (STOIC) experiment at the Jet Propulsion Laboratory Table Mountain Facility (TMF) (34.4 degrees N, 117.7 degrees W) in July and August 1989. Lidar temperatures, obtained on 21 nights preceding and during this experiment, are compared with temperatures derived by radiosondes, datasondes, Stratospheric Aerosol and Gas Experiment (SAGE II) satellite experiment, and National Meteorological Center (NMC) analyses. Radiosondes were flown from the TMF site as well as from San Nicholas Island (33.2 degrees N, 119.5 degrees W) located about 225 km southwest of TMF. Datasondes were deployed from Super-Loki rockets also launched at San Nicholas Island. SAGE II satellite temperature measurements were made within 1000 km of the Table Mountain site. NMC temperature analyses derived from the NOAA satellite measurements were interpolated to coincide in space and time with the lidar measurements. The lidar temperatures, which were derived for altitudes between 30 and 65 km, were within 2-3 K of the temperatures measured by the other sensors in the altitude range 30-45 km. Between 30 and 35 km, lidar temperatures were about 2 K cooler than those obtained from the datasondes and the NMC analyses but were about 1-2 K warmer than those obtained from the radiosonde, These differences may be due to the time difference between the measurements as well as possible nonnegligible aerosol scattering near 30 km. Near and above the stratopause the temperature differences increased to 3-8 K. Lidar temperature profiles also show small-scale variations possibly caused by wave activity. C1 UNIV SPACE RES ASSOC, LANHAM, MD USA. CHEMAL INC, WALLOPS ISL, VA 23337 USA. NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, TERR PHYS LAB, GREENBELT, MD 20771 USA. NOAA, ENVIRONM RES LAB, BOULDER, CO 80303 USA. NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23669 USA. NOAA, NATL WEATHER SERV, NATL METEOROL CTR, WASHINGTON, DC 20233 USA. UNIV MARYLAND, DEPT PHYS, COLLEGE PK, MD 20742 USA. NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, HYDROSPHER PROC LAB, WALLOPS ISL, VA 23337 USA. SCI & TECHNOL CORP, HAMPTON, VA 23669 USA. RI McGee, Thomas/G-4951-2013; Butler, James/D-4188-2013 NR 29 TC 16 Z9 17 U1 1 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 MAY 20 PY 1995 VL 100 IS D5 BP 9303 EP 9312 DI 10.1029/94JD02331 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QZ724 UT WOS:A1995QZ72400034 ER PT J AU SMITH, EJ MARSDEN, RG PAGE, DE AF SMITH, EJ MARSDEN, RG PAGE, DE TI ULYSSES ABOVE THE SUNS SOUTH-POLE - AN INTRODUCTION SO SCIENCE LA English DT Article AB Ulysses has explored the field and particle environment of the sun's polar region. The solar wind speed was fast and nearly constant above -50 degrees latitude. Compositional differences were observed in slow (low-latitude) solar wind and in fast (high-latitude) solar wind. The radial magnetic field did not change with latitude, implying that polar cap magnetic fields are transported, toward the equator. The intensity of galactic cosmic rays was nearly independent of latitude. Their access to the polar region is opposed by outward-traveling, large amplitude waves in the magnetic field. C1 EUROPEAN SPACE TECHNOL CTR,EUROPEAN SPACE AGCY,DEPT SPACE SCI,2200 AG NOORDWIJK,NETHERLANDS. RP SMITH, EJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 10 TC 45 Z9 46 U1 0 U2 1 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1005 EP 1007 DI 10.1126/science.7754377 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400027 PM 7754377 ER PT J AU BALOGH, A SMITH, EJ TSURUTANI, BT SOUTHWOOD, DJ FORSYTH, RJ HORBURY, TS AF BALOGH, A SMITH, EJ TSURUTANI, BT SOUTHWOOD, DJ FORSYTH, RJ HORBURY, TS TI THE HELIOSPHERIC MAGNETIC-FIELD OVER THE SOUTH POLAR-REGION OF THE SUN SO SCIENCE LA English DT Article ID SOLAR-WIND; ULYSSES OBSERVATIONS; TURBULENCE; EVOLUTION; STRENGTH; 1-AU AB Magnetic field measurements from the Ulysses space mission over the south polar regions of the sun showed that the structure and properties of the three-dimensional heliosphere were determined by the fast solar wind flow and magnetic fields from the large coronal holes in the polar regions of the sun. This conclusion applies at the current, minimum phase of the 11-year solar activity cycle. Unexpectedly, the radial component of the magnetic field was independent of latitude. The high-latitude magnetic field deviated significantly from the expected Parker geometry, probably because of large amplitude transverse fluctuations. Low-frequency fluctuations had a high level of variance. The rate of occurrence of discontinuities also increased significantly at high latitudes. C1 JET PROPULS LAB,PASADENA,CA 91109. RP BALOGH, A (reprint author), UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,PRINCE CONSORT RD,LONDON SW7 2BZ,ENGLAND. NR 35 TC 230 Z9 231 U1 1 U2 7 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1007 EP 1010 DI 10.1126/science.268.5213.1007 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400028 PM 17774226 ER PT J AU BAGUHL, M HAMILTON, DP GRUN, E DERMOTT, SF FECHTIG, H HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G STAUBACH, P ZOOK, HA AF BAGUHL, M HAMILTON, DP GRUN, E DERMOTT, SF FECHTIG, H HANNER, MS KISSEL, J LINDBLAD, BA LINKERT, D LINKERT, G MANN, I MCDONNELL, JAM MORFILL, GE POLANSKEY, C RIEMANN, R SCHWEHM, G STAUBACH, P ZOOK, HA TI DUST MEASUREMENTS AT HIGH ECLIPTIC LATITUDES SO SCIENCE LA English DT Article ID ULYSSES; JUPITER AB Along Ulysses' path from Jupiter to the south ecliptic pole, the onboard dust detector measured a dust impact rate that varied slowly from 0.2, to 0.5 impacts per day. The dominant component of the dust flux arrived from an ecliptic latitude and longitude of 10 degrees +/- 10 degrees and 280 degrees +/- 30 degrees which indicates an interstellar origin. An additional flux of small particles, which do not come from the interstellar direction and are unlikely to be zodiacal dust grains, appeared south of -45 degrees latitude. One explanation is that these particles are beta-meteoroids accelerated away from the sun by radiation pressure and electromagnetic forces. C1 UNIV FLORIDA,GAINESVILLE,FL 32611. JET PROPULS LAB,PASADENA,CA 91109. MAX PLANCK INST AERON,D-37191 KATLENBURG DUHM,GERMANY. LUND OBSERV,S-221 LUND,SWEDEN. UNIV KENT,CANTERBURY CT2 7NR,KENT,ENGLAND. MAX PLANCK INST EXTRATERR PHYS,D-85748 GARCHING,GERMANY. EUROPEAN SPACE TECHNOL CTR,2200 AG NOORDWIJK,NETHERLANDS. NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP BAGUHL, M (reprint author), MAX PLANCK INST KERNPHYS,D-69029 HEIDELBERG,GERMANY. NR 19 TC 27 Z9 27 U1 0 U2 0 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1016 EP 1019 DI 10.1126/science.268.5213.1016 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400031 PM 17774227 ER PT J AU STONE, RG MACDOWALL, RJ FAINBERG, J HOANG, S KAISER, ML KELLOGG, PJ LIN, N OSHEROVICH, VA BOUGERET, JL CANU, P CORNILLEAUWEHRLIN, N DESCH, MD GOETZ, K GOLDSTEIN, ML HARVEY, CC LENGYELFREY, D MANNING, R REINER, MJ STEINBERG, JL THEJAPPA, G AF STONE, RG MACDOWALL, RJ FAINBERG, J HOANG, S KAISER, ML KELLOGG, PJ LIN, N OSHEROVICH, VA BOUGERET, JL CANU, P CORNILLEAUWEHRLIN, N DESCH, MD GOETZ, K GOLDSTEIN, ML HARVEY, CC LENGYELFREY, D MANNING, R REINER, MJ STEINBERG, JL THEJAPPA, G TI ULYSSES RADIO AND PLASMA-WAVE OBSERVATIONS AT HIGH SOUTHERN HELIOGRAPHIC LATITUDES SO SCIENCE LA English DT Article ID LANGMUIR-WAVES; SOLAR-WIND; BURSTS; FREQUENCY; ELECTRONS; EMISSION; HELIOS AB Ulysses spacecraft radio and plasma wave observations indicate that some variations in the intensity and occurrence rate of electric and magnetic wave events are functions of heliographic latitude, distance from the sun, and phase of the solar cycle. At high heliographic latitudes, solar type III radio emissions did not descend to the local plasma frequency, in contrast to the emission frequencies of some bursts observed in the ecliptic, Short-duration bursts of electrostatic and electromagnetic waves were often found in association with depressions in magnetic field amplitude, known as magnetic holes. Extensive wave activity observed in magnetic clouds may exist because of unusually large electron-ion temperature ratios. The lower number of intense in situ wave events at high latitudes was likely due to the decreased variability of the high-latitude solar wind. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. OBSERV PARIS,F-92195 MEUDON,FRANCE. UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455. HUGHES STX,LANHAM,MD 20706. CTR ETUD TERR & PLANETAIRES,F-78140 VELIZY VILLACOUBL,FRANCE. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. RI MacDowall, Robert/D-2773-2012; Goldstein, Melvyn/B-1724-2008 NR 29 TC 20 Z9 21 U1 0 U2 0 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1026 EP 1029 DI 10.1126/science.268.5213.1026 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400034 PM 17774230 ER PT J AU PHILLIPS, JL BAME, SJ FELDMAN, WC GOLDSTEIN, BE GOSLING, JT HAMMOND, CM MCCOMAS, DJ NEUGEBAUER, M SCIME, EE SUESS, ST AF PHILLIPS, JL BAME, SJ FELDMAN, WC GOLDSTEIN, BE GOSLING, JT HAMMOND, CM MCCOMAS, DJ NEUGEBAUER, M SCIME, EE SUESS, ST TI ULYSSES SOLAR-WIND PLASMA OBSERVATIONS AT HIGH SOUTHERLY LATITUDES SO SCIENCE LA English DT Article ID SECTOR STRUCTURE; EVOLUTION AB Solar wind plasma observations made by the Ulysses spacecraft through -80.2 degrees solar latitude and continuing equatorward to -40.1 degrees are summarized. Recurrent high-speed streams and corotating interaction regions dominated at middle latitudes. The speed of the solar wind was typically 700 to 800 kilometers per second poleward of -35 degrees. Corotating reverse shocks persisted farther south than did forward shocks because of the tilt of the heliomagnetic streamer belt. Sporadic coronal mass ejections were seen as far south as -60.5 degrees. Proton temperature was higher and the electron strahl was broader at higher latitudes. The high-latitude wind contained compressional, pressure-balanced, and Alfvenic structures. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. W VIRGINIA UNIV,DEPT PHYS,MORGANTOWN,WV 26506. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB ES82,HUNTSVILLE,AL 35812. RP PHILLIPS, JL (reprint author), LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,POB 1663,LOS ALAMOS,NM 87545, USA. NR 29 TC 148 Z9 150 U1 1 U2 4 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1030 EP 1033 DI 10.1126/science.268.5213.1030 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400035 PM 17774231 ER PT J AU GEISS, J GLOECKLER, G VONSTEIGER, R BALSIGER, H FISK, LA GALVIN, AB IPAVICH, FM LIVI, S MCKENZIE, JF OGILVIE, KW WILKEN, B AF GEISS, J GLOECKLER, G VONSTEIGER, R BALSIGER, H FISK, LA GALVIN, AB IPAVICH, FM LIVI, S MCKENZIE, JF OGILVIE, KW WILKEN, B TI THE SOUTHERN HIGH-SPEED STREAM - RESULTS FROM THE SWICS INSTRUMENT ON ULYSSES SO SCIENCE LA English DT Article ID POLAR CORONAL HOLE; SOLAR-WIND; MINOR IONS; IONIZATION EQUILIBRIUM; ABUNDANCES; SKYLAB; STATE AB The high-speed solar wind streaming from the southern coronal hole was remarkably uniform and steady and was confined by a sharp boundary that extended to the corona and chromosphere. Charge state measurements indicate that the electron temperature in this coronal hole reached a maximum;of about 1.5 million kelvin within 3 solar radii of the sun. This result, combined with the observed lack of depletion of heavy elements, suggests that an additional source of momentum is required to accelerate the polar wind. C1 UNIV MICHIGAN,DEPT ATMOSPHER OCEAN & SPACE SCI,ANN ARBOR,MI 48109. UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. MAX PLANCK INST AERON,D-37189 KATLENBURG DUHM,GERMANY. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP GEISS, J (reprint author), UNIV BERN,INST PHYS,CH-3012 BERN,SWITZERLAND. RI Von Steiger, Rudolf/F-6822-2011; Galvin, Antoinette/A-6114-2013 OI Von Steiger, Rudolf/0000-0002-3350-0023; NR 32 TC 194 Z9 194 U1 0 U2 2 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 19 PY 1995 VL 268 IS 5213 BP 1033 EP 1036 DI 10.1126/science.7754380 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY934 UT WOS:A1995QY93400036 PM 7754380 ER PT J AU MAZELY, TL FRIEDL, RR SANDER, SP AF MAZELY, TL FRIEDL, RR SANDER, SP TI PRODUCTION OF NO2 FROM PHOTOLYSIS OF PEROXYACETYL NITRATE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ULTRAVIOLET-ABSORPTION SPECTRUM; NITRIC-ACID VAPOR; LASER PHOTOLYSIS; QUANTUM YIELDS; 248 NM; PAN; DECOMPOSITION; RADICALS; HNO3; OH AB Peroxyacetyl nitrate (PAN) vapor was photolyzed at 248 nm, and the NO2 photoproduct was detected by laser-induced fluorescence. The quantum yield for the production of NO2 from PAN photolysis was determined by comparison to HNO3 photolysis data taken under identical experimental conditions. The average of data collected over a range of total pressures, precursor concentrations, and buffer gases was 0.83 +/- 0.09 for the NO2 quantum yield, where the statistical uncertainty is 2 standard deviations. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 43 TC 22 Z9 22 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD MAY 18 PY 1995 VL 99 IS 20 BP 8162 EP 8169 DI 10.1021/j100020a044 PG 8 WC Chemistry, Physical SC Chemistry GA QZ085 UT WOS:A1995QZ08500044 ER PT J AU FRENDI, A MAESTRELLO, L TING, L AF FRENDI, A MAESTRELLO, L TING, L TI AN EFFICIENT MODEL FOR COUPLING STRUCTURAL VIBRATIONS WITH ACOUSTIC RADIATION SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB In this paper, the problem of coupling between panel vibration and near and far field acoustic radiation is studied. The panel vibration is governed by the non-linear plate equations white the loading on the panel, which is the pressure difference across the panel, depends on the reflected and transmitted waves. Two models are used to solve this structural-acoustic interaction problem. One solves the three-dimensional non-linear Euler equations for the acoustic field coupled with the non-linear plate equations (the fully coupled model). The second uses the linear wave equation for the acoustic field and expresses the load as a double integral involving the panel oscillation (the decoupled model). The panel oscillation governed by a system of integro-differential equations is solved numerically and the acoustic field is then defined by an explicit formula. Numerical results are obtained using the two models for linear and non-linear panel vibration regimes excited by incident waves having different sound pressure levels. The predictions given by these two models are in good agreement, but the computational time needed for the "fully coupled model" is 60 times longer than that for "the decoupled model". C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23681 USA. COURANT INST MATH SCI, NEW YORK, NY 10012 USA. RP FRENDI, A (reprint author), ANALYT SERV & MAT INC, HAMPTON, VA 23666 USA. NR 16 TC 9 Z9 9 U1 0 U2 1 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X EI 1095-8568 J9 J SOUND VIB JI J. Sound Vibr. PD MAY 18 PY 1995 VL 182 IS 5 BP 741 EP 757 DI 10.1006/jsvi.1995.0230 PG 17 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA QZ288 UT WOS:A1995QZ28800006 ER PT J AU TOON, OB TOLBERT, MA AF TOON, OB TOLBERT, MA TI SPECTROSCOPIC EVIDENCE AGAINST NITRIC-ACID TRIHYDRATE IN POLAR STRATOSPHERIC CLOUDS SO NATURE LA English DT Article ID PHYSICAL-CHEMISTRY; OZONE DEPLETION; VAPOR-PRESSURES; CONDENSATION; ANTARCTICA; MECHANISMS; AEROSOLS; AIRCRAFT; SYSTEM AB HETEROGENEOUS reactions on polar stratospheric clouds (PSCs) play a key role in the photochemical mechanism thought to be responsible for ozone depletion in the Antarctic and the Arctic(1,2). Reactions on PSC particles activate chlorine to forms that are capable of photochemical ozone destruction, and sequester nitrogen oxides (NOx) that would otherwise deactivate the chlorine(3,4). Although the heterogeneous chemistry is now well established, the composition of the clouds themselves is uncertain. It is commonly thought that they are composed of nitric acid trihydrate(3), although observations have left this question unresolved(5-14). Here we reanalyse infrared spectra of type I PSCs obtained in Antarctica in September 1987(15,16), using recently measured optical constants of the various compounds that might be present in PSCs17. We find that these PSCs were not composed of nitric acid trihydrate but instead had a more complex composition, perhaps that of a ternary solution. Because cloud formation is sensitive to their composition, this finding will alter our understanding of the locations and conditions in which PSCs form. In addition, the extent of ozone loss depends on the ability of the PSCs to remove NOx permanently through sedimentation. The sedimentation rates depend on PSC particle size which in turn is controlled by the composition and formation mechanism(14). C1 UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. UNIV COLORADO,CIRES,BOULDER,CO 80309. RP TOON, OB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 30 TC 72 Z9 72 U1 0 U2 2 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD MAY 18 PY 1995 VL 375 IS 6528 BP 218 EP 221 DI 10.1038/375218a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QY881 UT WOS:A1995QY88100057 ER PT J AU XU, YC LEE, SA FREISER, BS BAUSCHLICHER, CW AF XU, YC LEE, SA FREISER, BS BAUSCHLICHER, CW TI ORGANOMETALLIC DISTONIC IONS - (FEC6H4-CENTER-DOT)-FE-+ SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID TRANSFORM MASS-SPECTROMETRY; GAS-PHASE REACTIONS; FE+-BENZYNE; RADICAL CATIONS; RESONANCE; COLLISION; DISSOCIATION C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP XU, YC (reprint author), PURDUE UNIV,HC BROWN & RB WETHERILL LABS CHEM,W LAFAYETTE,IN 47907, USA. NR 23 TC 18 Z9 18 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 17 PY 1995 VL 117 IS 19 BP 5413 EP 5414 DI 10.1021/ja00124a046 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA QY885 UT WOS:A1995QY88500046 ER PT J AU GAZIS, PR RICHARDSON, JD PAULARENA, KI AF GAZIS, PR RICHARDSON, JD PAULARENA, KI TI LONG-TERM PERIODICITY IN SOLAR-WIND VELOCITY DURING THE LAST 3 SOLAR-CYCLES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FLUCTUATIONS; PIONEER; EARTH AB Solar wind measurements from the Pioneer 10, Pioneer 11, Voyager 2, IMP 8, and Pioneer Venus Orbiter (PVO) spacecraft were examined to search for long-term periodicities during the last three solar cycles. For the time of the last, solar maximum, these measurements confirm the existence of the periodic 1.3-year enhancements in solar wind velocity reported by Richardson et al. [1994] For most of the preceding two solar cycles, long-term velocity enhancements occurred that were similar in structure but lacked the 1.3-year periodicity. It appears that long-term enhancements in solar wind velocity, with durations on the order of a few months to a year, are a common feature throughout the heliosphere. C1 MIT, CTR SPACE RES, CAMBRIDGE, MA 02139 USA. RP SAN JOSE STATE UNIV FDN, NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 13 TC 39 Z9 39 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1995 VL 22 IS 10 BP 1165 EP 1168 DI 10.1029/95GL01017 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QZ219 UT WOS:A1995QZ21900002 ER PT J AU LOCKWOOD, M COWLEY, SWH SMITH, MF RIJNBEEK, RP ELPHIC, RC AF LOCKWOOD, M COWLEY, SWH SMITH, MF RIJNBEEK, RP ELPHIC, RC TI THE CONTRIBUTION OF FLUX-TRANSFER EVENTS TO CONVECTION SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETOPAUSE; RECONNECTION; IONOSPHERE AB It is shown from flux transfer event (FTE) occurrence statistics, observed as a function of MLT by the ISEE satellites, that recent 2-dimensional analytic theories of the effects of pulsed Petschek reconnection predict FTEs to contribute between 50 and 200 kV to the total reconnection voltage when the magnetosheath field points southward. The upper limit (200 kV) allows the possibility that FTEs provide all the antisunward transport of open field lines into the tail lobe. This range is compared with the voltages associated with series of FTEs signatures, as inferred from ground-based observations, which are in the range 10-60 kV. We conclude that the contribution could sometimes be made by a series of single, large events; however, the voltage is often likely to be contributed by several FTEs at different MLT. C1 UNIV LONDON IMPERIAL COLL SCI & TECHNOL,BLACKETT LAB,LONDON,ENGLAND. NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV SUSSEX,CTR SPACE SCI,FALMER,E SUSSEX,ENGLAND. LOS ALAMOS NATL LAB,LOS ALAMOS,NM. RP LOCKWOOD, M (reprint author), RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. RI Lockwood, Mike/G-1030-2011 OI Lockwood, Mike/0000-0002-7397-2172 NR 18 TC 36 Z9 36 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 MAY 15 PY 1995 VL 22 IS 10 BP 1185 EP 1188 DI 10.1029/95GL01008 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QZ219 UT WOS:A1995QZ21900007 ER PT J AU LEPPING, RP FAIRFIELD, DH JONES, J FRANK, LA PATERSON, WR KOKUBUN, S YAMAMOTO, T AF LEPPING, RP FAIRFIELD, DH JONES, J FRANK, LA PATERSON, WR KOKUBUN, S YAMAMOTO, T TI CROSS-TAIL MAGNETIC-FLUX ROPES AS OBSERVED BY THE GEOTAIL SPACECRAFT SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOMAGNETIC TAIL; PLASMA SHEET; MAGNETOTAIL; CDAW-8 AB Ten transient magnetic structures in Earth's magnetotail, as observed in GEOTAIL measurements, selected for early 1993 [at (-) X(GSM) = 90 - 130 R(E)], are shown to have helical magnetic field configurations similar to those of interplanetary magnetic clouds at 1 AU but smaller in size by a factor of approximate to 700. Such structures are shown to be well approximated by a comprehensive magnetic force-free flux-rope model. For this limited set of 10 events the rope axes are seen to be typically aligned with the Y-GSM axis and the average diameter of these structures is approximate to 15 RE. C1 HUGHES STX CORP,GREENBELT,MD. UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52242. NAGOYA UNIV,SOLAR TERR ENV LAB,NAGOYA,AICHI,JAPAN. ISAS,SAGAMIHARA,KANAGAWA,JAPAN. RP LEPPING, RP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,LEP,CODE 696,GREENBELT,MD 20771, USA. RI Paterson, William/F-5684-2012 NR 18 TC 33 Z9 34 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 MAY 15 PY 1995 VL 22 IS 10 BP 1193 EP 1196 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QZ219 UT WOS:A1995QZ21900009 ER PT J AU STOCKMAN, SA FREY, H AF STOCKMAN, SA FREY, H TI NOACHIAN AND HESPERIAN MODIFICATION OF THE ORIGINAL CHRYSE IMPACT BASIN TOPOGRAPHY SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MARS; EVOLUTION AB We propose a new center and ring assignment for the original Chryse impact basin based upon photogeologic mapping of Noachian outcrops and re-examination of the published geology using orthographic projections. While others have centered the Chryse impact on the topographic low associated with Hesperian volcanic and fluvial deposits, we suggest that the center of the Noachian-age excavation cavity was located approximately 800 km to the north, and that the basin topography was modified significantly from the Noachian into the Hesperian. Evolution of the topographic low included structural modification by a later impact centered in Acidalia, restricted volcanic deposition and loading, localized subsidence, and restricted deposition from the circum-Chryse outflow channels. C1 SCI SYST & APPLICAT,LANHAM,MD. RP STOCKMAN, SA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 921,GREENBELT,MD 20771, USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 1995 VL 22 IS 10 BP 1269 EP 1272 DI 10.1029/95GL01111 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QZ219 UT WOS:A1995QZ21900028 ER PT J AU MAZURUK, K SU, CH LEHOCZKY, SL ROSENBERGER, F AF MAZURUK, K SU, CH LEHOCZKY, SL ROSENBERGER, F TI NOVEL OSCILLATING CUP VISCOMETER-APPLICATION TO MOLTEN HGTE AND HG0.8CD0.2TE SO JOURNAL OF APPLIED PHYSICS LA English DT Article C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. UNIV ALABAMA,CTR MICROGRAV & MAT RES,HUNTSVILLE,AL 35899. NR 13 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1995 VL 77 IS 10 BP 5098 EP 5102 DI 10.1063/1.359319 PG 5 WC Physics, Applied SC Physics GA QY839 UT WOS:A1995QY83900032 ER PT J AU FATEMI, NS WEIZER, VG AF FATEMI, NS WEIZER, VG TI ELECTRICAL AND METALLURGICAL BEHAVIOR OF AU/ZN CONTACTS TO P-TYPE INDIUM-PHOSPHIDE SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID AU-INP INTERACTION; OHMIC CONTACTS; RESISTANCE C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP FATEMI, NS (reprint author), ESSENTIAL RES INC,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 18 TC 8 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1995 VL 77 IS 10 BP 5241 EP 5247 DI 10.1063/1.359275 PG 7 WC Physics, Applied SC Physics GA QY839 UT WOS:A1995QY83900058 ER PT J AU RUFENACH, CL LIU, AK AF RUFENACH, CL LIU, AK TI GEOPHYSICAL AND OCEANOGRAPHIC INFORMATION IN THE MARGINAL ICE-ZONE FROM OCEAN WAVE MEASUREMENTS - COMMENTS SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Note C1 NASA,GODDARD SPACE FLIGHT CTR,OCEANS & ICE BRANCH,GREENBELT,MD 20771. RP RUFENACH, CL (reprint author), ENVIRONM RES INST MICHIGAN,POB 134001,ANN ARBOR,MI 48113, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 15 PY 1995 VL 100 IS C5 BP 8849 EP 8849 DI 10.1029/95JC00536 PG 1 WC Oceanography SC Oceanography GA QY345 UT WOS:A1995QY34500024 ER PT J AU MURPHY, DM GARY, BL AF MURPHY, DM GARY, BL TI MESOSCALE TEMPERATURE-FLUCTUATIONS AND POLAR STRATOSPHERIC CLOUDS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID VAPOR-PRESSURES; NITRIC-ACID; DENITRIFICATION; AIRCRAFT; GROWTH; SYSTEM AB Remote sensing measurements of temperature fluctuations on isentropic surfaces, as well as in situ measurements, are used to show that even high-resolution trajectory calculations seriously underestimate the rate of change of temperature experienced by air parcels. Rapid temperature fluctuations will affect the nucleation of polar stratospheric cloud (PSC) droplets and could promote the formation of metastable phases in PSCs. Mesoscale temperature fluctuations are large enough to produce significant departures from equilibrium in established PSCs. The large cooling rates experienced by air parcels have important implications for denitrification and dehydration nearly all condensation nuclei should be activated when a PSC is first formed and mass must be redistributed to larger aerosols during the evolution of a PSC if denitrification is to occur. C1 CALTECH,JET PROP LAB,PASADENA,CA. RP MURPHY, DM (reprint author), NOAA,AERON LAB,325 BROADWAY,BOULDER,CO 80303, USA. NR 34 TC 31 Z9 31 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 15 PY 1995 VL 52 IS 10 BP 1753 EP 1760 DI 10.1175/1520-0469(1995)052<1753:MTFAPS>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RC364 UT WOS:A1995RC36400016 ER PT J AU SCHLEGEL, EM MUKAI, K AF SCHLEGEL, EM MUKAI, K TI A ROSAT PSPC OBSERVATION OF THE ECLIPSING AM HER CATACLYSMIC VARIABLE EP DRACONIS (=H1907+690) SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE BINARIES, ECLIPSING; STARS, INDIVIDUAL, EP DRA; NOVAE, CATACLYSMIC VARIABLES; X-RAYS, STARS ID RAY AB This paper reports on the first detailed X-ray observation of the eclipsing AM Her cataclysmic variable EP Dra, using the ROSAT PSPC. The extracted PSPC spectrum of EP Dra shows the characteristic AM Her spectrum, with a blackbody component of similar to 10(-15) keV. The X-ray light curve shows an eclipse slightly offset from the pulse maximum. There is slight evidence for structure in the softer emitting regions as compared with the harder emitting regions. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. NR 16 TC 4 Z9 4 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 15 PY 1995 VL 274 IS 2 BP 555 EP 558 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QZ100 UT WOS:A1995QZ10000026 ER PT J AU BRADY, MP SMIALEK, JL TEREPKA, F AF BRADY, MP SMIALEK, JL TEREPKA, F TI MICROSTRUCTURE OF ALUMINA-FORMING OXIDATION-RESISTANT AL-TI-CR ALLOYS SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID BEHAVIOR; COATINGS; PHASES RP BRADY, MP (reprint author), NASA,LEWIS RES CTR,MS 106-1,CLEVELAND,OH 44135, USA. RI Brady, Michael/A-8122-2008 OI Brady, Michael/0000-0003-1338-4747 NR 17 TC 40 Z9 44 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD MAY 15 PY 1995 VL 32 IS 10 BP 1659 EP 1664 DI 10.1016/0956-716X(95)00251-P PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA QX018 UT WOS:A1995QX01800025 ER PT J AU HALICIOGLU, T AF HALICIOGLU, T TI STRESS CALCULATIONS ON DIAMOND SURFACES SO THIN SOLID FILMS LA English DT Article DE DIAMOND; STRESS; SURFACE STRESS ID SI(100) SURFACE; RECONSTRUCTION; ENERGIES AB Calculations were carried out to evaluate stresses for atoms located in the top several layers of the (100)-(1 x 1), (100)-(2 x 1) and (111)-(1 x 1) surfaces of diamond. Only equilibrated surfaces were taken into consideration in this investigation. Stress values in the direction perpendicular to the exposed surface vanish. In lateral directions, however, stresses have non-vanishing values, in general. For the (100) surfaces calculated stress values are anisotropic. While the (2 x 1) reconstructed surface is under compression in both directions, calculations for the unreconstructed (1 x 1) plane produced a compressive stress in one direction and a slight tension in the other. On the (111) surface, isotropic and relatively low compressive stress values were found. Present calculations indicate that atoms located only in a few tap layers have lateral excess stresses which vanish very quickly for the atoms of interior layers as depart form the exposed surface. RP HALICIOGLU, T (reprint author), NASA,AMES RES CTR,INST THERMOSCI,MS 230-3,MOFFETT FIELD,CA 94035, USA. NR 12 TC 3 Z9 3 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 MAY 15 PY 1995 VL 260 IS 2 BP 200 EP 204 DI 10.1016/0040-6090(94)06509-8 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA RA214 UT WOS:A1995RA21400011 ER PT J AU HO, CH CHA, YHC PRAKASH, S POTWIN, G DOERR, HJ DESHPANDEY, CV BUNSHAH, RF ZELLER, M AF HO, CH CHA, YHC PRAKASH, S POTWIN, G DOERR, HJ DESHPANDEY, CV BUNSHAH, RF ZELLER, M TI ELECTRICAL-RESISTANCE DRIFT OF MOLYBDENUM SILICIDE THIN-FILM TEMPERATURE SENSORS SO THIN SOLID FILMS LA English DT Article DE ELECTRICAL PROPERTIES AND MEASUREMENTS; SENSORS; SILICIDES; SPUTTERING ID TRANSPORT-PROPERTIES AB For a thermometer to be of practical use, its accuracy of temperature indication must be within a tolerable range. In this paper, patterned molybdenum disilicide (MoSi2) thin film temperature sensors were fabricated to study their thermoresistance, i.e. resistance vs. temperature (R-T) characteristics. The R-T characteristic of MoSi2 thin films exhibits a positive deviation from linearity (termed ''superlinearity'') instead of showing a simple linearity as for most metals. This superlinear behavior was attributed to thermal expansion and the consequent decrease in the Debye characteristic temperature of MoSi2. For long-term duration at elevated temperatures, the variation in thickness and composition of the sensor film due to oxidation and other factors may produce drift in the electrical resistance. In this study, the electrical resistance drifts of the sensors as a function of time at temperatures of 1200, 1300 and 1350 degrees C are presented. For the sensor him tested at 1300 degrees C, the resistance drift due to the thickness change of the sensor layer was well corrected with the help of an analysis of the oxidation rate of the sensor material. On the other hand, the in-depth composition profile analyzed by Auger electron spectroscopy (AES) indicated no significant composition variation, implying that we could neglect the correction factor for the composition variation in the present study. After the thickness factor was corrected for, a minor drift was still observed; this was also found for the same sensor film tested in an Ar ambient. The exact source of the minor drift is not well understood; further investigations are required. C1 UNIV CALIF LOS ANGELES,DEPT MAT SCI & ENGN,LOS ANGELES,CA 90024. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP HO, CH (reprint author), SILICONIX INC,2201 LAURELWOOD RD,SANTA CLARA,CA 95056, USA. NR 12 TC 7 Z9 7 U1 2 U2 5 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 MAY 15 PY 1995 VL 260 IS 2 BP 232 EP 238 DI 10.1016/0040-6090(94)06453-9 PG 7 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA RA214 UT WOS:A1995RA21400017 ER PT J AU CHOW, PL MAESTRELLO, L AF CHOW, PL MAESTRELLO, L TI STABILIZATION OF NONLINEAR PANEL VIBRATIONS BY BOUNDARY DAMPING SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB By introducing boundary damping, the exponential stabilization of a non-linear elastic panel is considered. With the left edge clamped, a combination of a bending moment and two point forces is applied to the right edge. For no flow, we find that the free panel vibration under a static compressive loading can be stabilized by a tensile force and boundary damping. The applied tensile force, if needed, is to produce a net thrust below a critical level for buckling, and the boundary damping is introduced by a frictional force and a braking torque, which may be regarded as a passive control and depends linearly on the transverse and angular velocities of the controlled edge. For time-dependent flow and compressive loading, it is shown that the fluttering panel can be stabilized, either when a flow parameter fluctuates and decays rapidly or when the flow parameter and the rate of change in compression are both small. In all cases, sufficient conditions for stability are given explicitly. Numerical examples are provided for the purpose of illustration. C1 NASA,LANGLEY RES CTR,DIV ACOUST,HAMPTON,VA 23665. RP CHOW, PL (reprint author), WAYNE STATE UNIV,DEPT MATH,DETROIT,MI 48202, USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS (LONDON) LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD MAY 11 PY 1995 VL 182 IS 4 BP 541 EP 558 DI 10.1006/jsvi.1995.0215 PG 18 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA QY357 UT WOS:A1995QY35700003 ER PT J AU VANOMMEN, TD JONES, DL PRESTON, RA JAUNCEY, DL AF VANOMMEN, TD JONES, DL PRESTON, RA JAUNCEY, DL TI TIME-DELAY IN THE EINSTEIN RING PKS-1830-211 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (PKS 1830-211); GRAVITATIONAL LENSING; RADIO CONTINUUM, GALAXIES ID RADIO-SOURCE AB We present radio observations of the gravitational lens PKS 1830-211 at 8.4 and 15 GHz acquired using the Very Large Array. The observations were made over a 13 month period. Significant flux density changes over this period provide strong constraints on the time delay between the two lensed images and suggest a value of 44 +/- 9 days. This offers new direct evidence that this source is indeed a gravitational lens. The lens distance is dependent upon the model chosen, but reasonable limits on the mass of the lensing galaxy suggest that it is unlikely to be at a redshift less than a few tenths, and may well be significantly more distant. C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. RI van Ommen, Tas/B-5020-2012 OI van Ommen, Tas/0000-0002-2463-1718 NR 10 TC 29 Z9 29 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP 561 EP 566 DI 10.1086/175630 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100007 ER PT J AU DAVIS, DS MUSHOTZKY, RF MULCHAEY, JS WORRALL, DM BIRKINSHAW, M BURSTEIN, D AF DAVIS, DS MUSHOTZKY, RF MULCHAEY, JS WORRALL, DM BIRKINSHAW, M BURSTEIN, D TI DIFFUSE HOT GAS IN THE NGC-4261 GROUP OF GALAXIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, CLUSTERS OF; GALAXIES, INDIVIDUAL (NGC 4261, NGC 4264, NGC 4273); INTERGALACTIC MEDIUM; X-RAYS, GALAXIES ID X-RAY-EMISSION; SPIRAL GALAXIES; COMPACT-GROUPS; DARK MATTER; CLUSTERS; EINSTEIN AB We have found diffuse X-ray gas in the group of galaxies containing the elliptical galaxy NGC 4261. This galaxy along with its associated companions are behind the Virgo cluster in the W-cloud. A recent analysis of the velocity structure in the Virgo region indicates that the W-cloud has similar to 30 members, most of which are low luminosity dwarfs. The hot X-ray emitting gas is centered about halfway between NGC 4261 and NGC 4264 and extends out to a radius of similar to 40' (620 kpc). The spectral data for the diffuse component are well fitted with a Raymond-Smith plasma model with a temperature of 0.85(-0.16)(+0.21) keV and abundance <0.08 times the solar value. Under the assumption that the diffuse gas is in hydrostatic equilibrium the total mass within 40' is 1.9 x 10(13) M(.). We estimate that the total baryonic mass of the hot gas and the galaxies is 20%-34% of the total mass in the central 40' radius of this group. This group of galaxies contains NGC 4273 which exhibits a ''bow shock'' morphology similar to that of NGC 2276, This is thought to occur when the ram pressure from the intragroup gas significantly perturbs the interstellar medium in a late-type galaxy. We show that this is unlikely in this group. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. NR 26 TC 22 Z9 22 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP 582 EP 589 DI 10.1086/175632 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100009 ER PT J AU OLIVE, KA ROOD, RT SCHRAMM, DN TRURAN, J VANGIONIFLAM, E AF OLIVE, KA ROOD, RT SCHRAMM, DN TRURAN, J VANGIONIFLAM, E TI WHAT IS THE PROBLEM WITH HE-3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXY, EVOLUTION; ISM, ABUNDANCES; NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES ID INTERMEDIATE-MASS STARS; PRIMORDIAL NUCLEOSYNTHESIS; CHEMICAL EVOLUTION; BRANCH; MODELS; END AB We consider the galactic evolutionary history of He-3 in models which deplete deuterium by as much as a factor of 2 to similar to 15 from its primordial value to its present-day observed value in the interstellar medium (ISM). We show that when 3He production in low-mass stars (1-3 M(.)) is included over the history of the galaxy, He-3 is greatly overproduced and exceeds the inferred solar values and the abundances determined in galactic H II regions. Furthermore, the ISM abundances show a disturbing dispersion which is difficult to understand from the point of view of standard chemical evolution models. In principle, resolution of the problem may lie in either (1) the calculated He-3 production in low-mass stars; (2) the observations of the He-3 abundance; or (3) an observational bias toward regions of depleted He-3. Since He-3 observations in planetary nebula support the calculated He-3 production in low-mass stars, option (1) is unlikely. We will argue for option (3) since the He-3 interstellar observations are indeed made in regions dominated by massive stars in which He-3 is destroyed. In conclusion, we note that the problem with He-3 seems to be galactic and not cosmological. C1 UNIV VIRGINIA,DEPT ASTRON,CHARLOTTESVILLE,VA 22903. UNIV CHICAGO,CHICAGO,IL 60637. INST ASTROPHYS,F-75014 PARIS,FRANCE. FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP OLIVE, KA (reprint author), UNIV MINNESOTA,SCH PHYS & ASTRON,MINNEAPOLIS,MN 55455, USA. NR 48 TC 51 Z9 51 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP 680 EP 685 DI 10.1086/175640 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100017 ER PT J AU SIMPSON, JP COLGAN, SWJ RUBIN, RH ERICKSON, EF HAAS, MR AF SIMPSON, JP COLGAN, SWJ RUBIN, RH ERICKSON, EF HAAS, MR TI FAR-INFRARED LINES FROM H-II REGIONS - ABUNDANCE VARIATIONS IN THE GALAXY SO ASTROPHYSICAL JOURNAL LA English DT Review DE H II REGIONS; ISM, ABUNDANCES; ISM, INDIVIDUAL (30 DORADUS) ID APERTURE SYNTHESIS OBSERVATIONS; RESOLUTION RADIO OBSERVATIONS; IONIZATION CORRECTION FACTORS; GUIDE STAR CATALOG; ORION NEBULA; CHEMICAL-COMPOSITION; HELIUM ABUNDANCE; GALACTIC-CENTER; CONTINUUM OBSERVATIONS; RECOMBINATION LINES AB Far-infrared lines of [N III] (57 mu m), [O III] (52, 88 mu m), [Ne III] (36 mu m), and [S III] (19, 33 mu m) have been measured in the H II regions G1.13-0.11, W31B, G23.95+0.15, G25.38-0.18, G29.96-0.02, W43, W51e, S156, S158, NGC 3576, NGC 3603, and G298.22-0.34. These observations were made with the facility Cryogenic Grating Spectrometer on the Kuiper Airborne Observatory to examine variations in abundances throughout the Galaxy. Previously published observations of G0.095+0.012, G333.60-0.21, G45.13+0.14A, K3-50, and M17 are also discussed. The giant H II region 30 Doradus in the Large Magellanic Cloud was observed for comparison. Fluxes for [Ne II] (12.8 mu m), [S IV] (10.5 mu m), and the radio free-free continuum were collected from the literature for these sources. Electron densities were estimated from FIR line-pair ratios, and ionic abundances were estimated from the FIR line and radio fluxes. The excitation was estimated from the O++/S++ ratio. Corrections for unseen ionization stages were calculated with the use of constant-density H II region models. The validity and range of applicability of such semiempirical ionization correction schemes are discussed. The abundances with respect to hydrogen exhibit gradients with R(G) comparable to those previously measured for our Galaxy and for other galaxies. The overall gradients are d (log N/H)/dR = -0.10 +/- 0.02 dex kpc(-1), d (log Ne/H)/dR = -0.08 +/- 0.02 dex kpc(-1), and d (log S/H)/dR -0.07 +/- 0.02 dex kpc(-1). Compared to the Orion Nebula, the intermediate R(G) H II, regions with 6 < R(G) < 11 kpc have similar or lower S/H and N/O ratios. The N/O ratios in the inner Galaxy are more than twice those observed in the Orion Nebula and intermediate R(G) H II regions. In fact, all the abundance ratios are as well or better fitted by a step fit with two levels than by a linear gradient. This is best exhibited by N/O: N/O = 0.32 +/- 0.02 for R(G) less than or equal to 6 kpc and N/O = 0.18 +/- 0.01 for 6.4 < R(G) < 10.2 kpc. The lowest N/O ratio (0.059 +/- 0.003) is found in 30 Doradus. As has been noted in previous studies, the N/O ratio estimated from infrared observations of the doubly ionized N and O lines in H II regions is larger than the ratio estimated from optical observations of the singly ionized N and O lines. The excitation, as shown by the O++/S++ ratio, also varies with R(G). Even though the H II regions were generally selected for high ionization on the basis of high He+/H+ radio recombination line ratios, the inner Galaxy H II regions all have low ionization (i.e., the oxygen and neon are mostly singly ionized), probably because they have higher abundances. The Ne++/O++ ratio is observed to be essentially constant over a wide range of excitation. This contradicts predictions of model H II regions calculated with the use of LTE model stellar atmospheres. We conclude that these stellar atmospheres significantly underestimate the actual emergent fluxes for energies >41 eV. C1 UNIV CALIF BERKELEY, DEPT ASTRON, BERKELEY, CA 94720 USA. SETI INST, MT VIEW, CA USA. RP SIMPSON, JP (reprint author), NASA, AMES RES CTR, MS 245-6, MOFFETT FIELD, CA 94035 USA. RI Colgan, Sean/M-4742-2014 NR 155 TC 153 Z9 153 U1 0 U2 2 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 MAY 10 PY 1995 VL 444 IS 2 BP 721 EP 738 DI 10.1086/175645 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100022 ER PT J AU BOWERS, CW BLAIR, WP LONG, KS DAVIDSEN, AF AF BOWERS, CW BLAIR, WP LONG, KS DAVIDSEN, AF TI HOPKINS ULTRAVIOLET TELESCOPE OBSERVATIONS OF H-2 TOWARD THE PLANETARY-NEBULA NGC-1535 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, MOLECULES; PLANETARY NEBULAE, INDIVIDUAL (NGC 1535); ULTRAVIOLET, ISM ID MOLECULAR-HYDROGEN EMISSION; CENTRAL STARS; MODEL ATMOSPHERES; STELLAR EVOLUTION; ABSORPTION; DUST; PARAMETERS; NGC-1535; REGIONS; GALAXY AB We have observed the far-ultraviolet spectrum (912-1860 Angstrom) of the bright high-excitation planetary nebula NGC 1535 with similar to 3 Angstrom resolution using the Hopkins Ultraviolet Telescope aboard the Astro-1 space shuttle mission in 1990 December. We see strong continuum emission down to the Lyman limit and strong P Cygni profiles from high-excitation lines such as C IV lambda 1549, N V lambda 1240 O V lambda 1371, and O VI lambda 1035. Below 1150 Angstrom strong absorption bands of H-2 are seen, which were unanticipated by us because of the low reddening and high galactic latitude of the object and the absence of detected H-2 emission in the infrared. We construct model H-2 spectra and convolve them to the HUT resolution for comparison with the NGC 1535 data. We find good agreement with a population distribution characterized by a single temperature (T = 300 K) or a two-temperature model (T = 144/500 K), and determine limits on the H-2 column density. While both interstellar and circumstellar origins for the observed H-2 absorption are plausible, we ascribe the material to the planetary nebula in order to estimate the conditions of excitation and place upper limits on the mass of both H-2 and H I in this system. Because the UV transitions are ground-state connected, we determine a stringent upper limit of 0.03d(1.6)(2) M. on the mass of H-2, where d(1.6) is the distance relative to an assumed distance of 1.6 kpc. This value is less model-dependent than IR estimates. Along with the central star and nebular masses, these estimates allow us to limit the main-sequence mass of the progenitor star to less than 1.8 M.. This upper limit is consistent with a relatively low-mass extended thick disk or Population II progenitor, as expected for an object similar to 1 kpc off the galactic plane. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. RP BOWERS, CW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 683-3,GREENBELT,MD 20771, USA. NR 61 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP 748 EP 757 DI 10.1086/175647 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100024 ER PT J AU GRAHAM, JR LEVENSON, NA HESTER, JJ RAYMOND, JC PETRE, R AF GRAHAM, JR LEVENSON, NA HESTER, JJ RAYMOND, JC PETRE, R TI AN X-RAY AND OPTICAL STUDY OF THE INTERACTION OF THE CYGNUS-LOOP SUPERNOVA REMNANT WITH AN INTERSTELLAR CLOUD SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, INDIVIDUAL (CYGNUS LOOP); SUPERNOVA REMNANTS; X-RAYS, ISM ID INTER-STELLAR MEDIUM; EINSTEIN OBSERVATIONS; WAVE; PRECURSORS; EMISSION AB We have used the ROSAT high-resolution imager and optical emission line data to study the structure of a bright optical knot on the southeastern rim of the Cygnus Loop supernova remnant. This knot has been identified as an encounter between the blast wave and a small isolated cloud. The knot appears in projection just behind the blast wave, which is traced by Balmer line filaments which bound the X-ray emission. The knot is a prominent X-ray feature, consisting of a number of filaments which are correlated with the optical line emission. These data permit a detailed view of the blast wave interaction. By combining the optical and X-ray data it is possible to trace the blast wave as a continuous surface from its southern edge around the western side of the cloud that then continues on to the north. The southeastern knot is an indentation on the surface of the blast wave. Thus the southeastern knot is not a small cloud that has been overrun by the blast wave, but the tip of a larger cloud. Bright X-ray emission is associated with bright radiative filaments. The location of this emission, upstream of the radiative shocks, implies that the enhanced X-rays come from a reverse shock. The presence of a reverse shock is further evidence that the southeastern knot represents an early stage of a blast wave encountering a large cloud. A consistent picture of the Cygnus Loop as an explosion within a preexisting cavity is emerging. These observations agree with that picture. C1 ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP GRAHAM, JR (reprint author), UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720, USA. NR 32 TC 45 Z9 45 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP 787 EP 795 DI 10.1086/175651 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV701 UT WOS:A1995QV70100028 ER PT J AU GORSKI, KM RATRA, B SUGIYAMA, N BANDAY, AJ AF GORSKI, KM RATRA, B SUGIYAMA, N BANDAY, AJ TI COBE DMR-NORMALIZED OPEN INFLATION, COLD DARK-MATTER COSMOGONY SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; COSMOLOGY, OBSERVATIONS; GALAXIES, FORMATION; LARGE-SCALE STRUCTURE OF THE UNIVERSE ID UNIVERSE AB A cut-sky orthogonal mode analysis of the 2 year COBE DMR 53 and 90 GHz sky maps (in Galactic coordinates) is used to determine the normalization of an open inflation model based on the cold dark matter scenario. The normalized model is compared to measures of large-scale structure in the universe. Although the DMR data alone does not provide sufficient discriminative power to prefer a particular value of the mass density parameter, the open model appears to be reasonably consistent with observations when Omega(0) similar to 0.3-0.4 and merits further study. C1 UNIV WARSAW OBSERV,PL-00478 WARSAW,POLAND. PRINCETON UNIV,JOSEPH HENRY LABS,PRINCETON,NJ 08544. UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV TOKYO,FAC SCI,DEPT PHYS,TOKYO 113,JAPAN. RP GORSKI, KM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 685,GREENBELT,MD 20771, USA. RI Ratra, Bharat/I-4979-2012 NR 39 TC 52 Z9 51 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP L65 EP L68 DI 10.1086/187861 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV709 UT WOS:A1995QV70900002 ER PT J AU HUGHES, JP HAYASHI, I HELFAND, D HWANG, U ITOH, M KIRSHNER, R KOYAMA, K MARKERT, T TSUNEMI, H WOO, J AF HUGHES, JP HAYASHI, I HELFAND, D HWANG, U ITOH, M KIRSHNER, R KOYAMA, K MARKERT, T TSUNEMI, H WOO, J TI ASCA OBSERVATIONS OF THE LARGE MAGELLANIC CLOUD SUPERNOVA REMNANT SAMPLE - TYPING SUPERNOVAE FROM THEIR REMNANTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INDIVIDUAL (LARGE MAGELLANIC CLOUD); NUCLEAR REACTIONS, NUCLEOSYNTHESIS, ABUNDANCES; SUPERNOVA REMNANTS; X-RAYS, ISM ID NOVA REMNANTS; X-RAY; MODELS AB We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, and Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last similar to 1500 yr came from Type Ia SNs. C1 KYOTO UNIV,DEPT PHYS,SAKYO KU,KYOTO 606,JAPAN. COLUMBIA UNIV,DEPT ASTRON,NEW YORK,NY 10027. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. OSAKA UNIV,DEPT PHYS,TOYONAKA,OSAKA 560,JAPAN. RP HUGHES, JP (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. NR 23 TC 80 Z9 80 U1 2 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP L81 EP L84 DI 10.1086/187865 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV709 UT WOS:A1995QV70900006 ER PT J AU WANG, H GARY, DE ZIRIN, H KOSUGI, T SCHWARTZ, RA LINFORD, G AF WANG, H GARY, DE ZIRIN, H KOSUGI, T SCHWARTZ, RA LINFORD, G TI THE MICROWAVE AND H-ALPHA SOURCES OF THE 1992 JANUARY 13 FLARE SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, FLARES; SUN, RADIO RADIATION; SUN, X-RAYS, GAMMA RAYS ID SOLAR-FLARES; JULY 11; ECLIPSE AB We compare X-ray, microwave and Ha observations for the 1992 January 13 limb flare. The soft and hard X-ray images of this flare have been studied thoroughly by Masuda et al. (1994) with Yohkoh SXT and HXT images. We find that during the hard X-ray emission peak there is no Ha brightening on the disk nor at the limb, so the main ribbons of this flare must be beyond the limb. The microwave source maintains a fixed distance about 10 '' from the optical limb in the frequency range 2.8-14.0 GHz. We interpret this limit in source position as due to the presence of a microwave limb that extends higher than the white-light limb-to a height of 7300 +/- 1500 km. We believe that the high-frequency microwave emissions are occulted by this extended limb, while the soft and hard X-ray emissions are able to pass through largely unaffected. We also believe, however, that the hard X-ray footpoints are also partially occulted by the photospheric limb, despite the appearance of ''footpoint sources'' in HXT data shown by Masuda et al. The smooth X-ray and microwave time profiles, microwave-rich emission relative to hard X-rays, and progressive hard X-ray spectral hardening through the flare peak are all characteristics that we interpret as being a direct result of the occultation of footpoint emission. C1 NATL ASTRON OBSERV,MITAKA,TOKYO 181,JAPAN. NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX,HAGERSTOWN,MD 21748. LOCKHEED PALO ALTO RES LABS,PALO ALTO,CA 94304. LOCKHEED PALO ALTO RES LABS,DEPT 9130,PALO ALTO,CA. RP WANG, H (reprint author), CALTECH,BIG BEAR SOLAR OBSERV,MS 264-33,PASADENA,CA 91125, USA. NR 14 TC 20 Z9 21 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 1995 VL 444 IS 2 BP L115 EP L118 DI 10.1086/187873 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV709 UT WOS:A1995QV70900014 ER PT J AU KRABILL, WB THOMAS, RH MARTIN, CF SWIFT, RN FREDERICK, EB AF KRABILL, WB THOMAS, RH MARTIN, CF SWIFT, RN FREDERICK, EB TI ACCURACY OF AIRBORNE LASER ALTIMETRY OVER THE GREENLAND ICE-SHEET SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article AB During September 1991, April 1992 and June/July 1993, a NASA P-3 aircraft, equipped with a scanning laser altimeter, flew numerous transects of the Greenland ice sheet. The aeroplane location was measured precisely using differential Global Positioning System (GPS) surveying techniques, allowing all altimetry data to be converted into measurements of ice-surface elevation relative to the Earth ellipsoid. Results from flight data indicate that ice-surface elevations can be reliably measured to an accuracy of similar to 20 cm (and possibly to similar to 10 cm) over baselines of more than seven hundred kilometres. C1 NASA HEADQUARTERS,WASHINGTON,DC 20546. EG&G WASHINGTON ANALYT SERV CORP,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337. RP KRABILL, WB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,HYDROSPHER PROC LAB,WALLOPS ISL,VA 23337, USA. NR 8 TC 125 Z9 125 U1 0 U2 9 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 10 PY 1995 VL 16 IS 7 BP 1211 EP 1222 PG 12 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA RG051 UT WOS:A1995RG05100002 ER PT J AU PENG, CY LIU, AK AF PENG, CY LIU, AK TI SYNTHETIC-APERTURE RADAR OBSERVATIONS OF INTERACTION OF OCEAN SWELL AND SEMIDI ISLANDS IN THE GULF OF ALASKA SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID WAVE; SPECTRA AB Synthetic aperture radar (SAR) images of the ocean surface can show evidence of the sheltering effects of barriers, such as islands, on the incoming long ocean waves. In the presence of high background noise in SAR images, these effects are not always observed by visual inspection. As shown in this paper, they can be determined most effectively in the spectral domain. From the ERS-1 SAR data of 17 October 1991, we noticed that two separate swell components almost perpendicular to each other were incident on the Semidi Islands in the Gulf of Alaska. By spectral analysis, the shadow zone associated with each wave component can be identified. The distribution of an equivalent diffraction coefficient has been estimated at the lee of the Chowiet Island which has a sharp tip. It has been compared to that obtained from the Sommerfeld solution of diffraction for a semi-infinite barrier. The SAR data shows a similar diffraction pattern to the model solution but has a slower fall-off into the geometric shadow zone. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP PENG, CY (reprint author), SCI SYST & APPLICAT INC,LANHAM,MD 20771, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS LTD LONDON PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAY 10 PY 1995 VL 16 IS 7 BP 1249 EP 1260 PG 12 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA RG051 UT WOS:A1995RG05100005 ER PT J AU GATES, EI GYUK, G TURNER, MS AF GATES, EI GYUK, G TURNER, MS TI MICROLENSING AND HALO COLD DARK-MATTER SO PHYSICAL REVIEW LETTERS LA English DT Article ID GALACTIC HALO; KINEMATICS; OBJECTS; GALAXY; BULGE; MODEL C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. RP GATES, EI (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637, USA. NR 45 TC 50 Z9 50 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 1995 VL 74 IS 19 BP 3724 EP 3727 DI 10.1103/PhysRevLett.74.3724 PG 4 WC Physics, Multidisciplinary SC Physics GA QW900 UT WOS:A1995QW90000003 ER PT J AU RIND, D AF RIND, D TI DRYING OUT SO NEW SCIENTIST LA English DT Article RP RIND, D (reprint author), NASA,GODDARD INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 SN 0262-4079 J9 NEW SCI JI New Sci. PD MAY 6 PY 1995 VL 146 IS 1976 BP 36 EP 40 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QX833 UT WOS:A1995QX83300033 ER PT J AU BAUSCHLICHER, CW RICCA, A AF BAUSCHLICHER, CW RICCA, A TI ON THE INTERACTION OF CO AND NH3 WITH BH3 AND BF3 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DONOR-ACCEPTOR COMPLEXES; MICROWAVE-SPECTRUM; ELECTRON; ENERGY; ATOMS AB BH3CO, BF3CO, BH3NH3, and BF3NH3 have been studied using density functional theory. The computed geometries are in reasonable agreement with experiment. BF3CO is found to be weakly bound. The binding energies of BH3CO, BH3NH3, and BF3NH3 have also been computed using the coupled cluster singles and doubles level of theory, including a perturbational estimate of the connected triples. These are expected to be the most accurate binding energies to date. The bonding is analyzed using the constrained space orbital variation technique. RP BAUSCHLICHER, CW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 33 TC 43 Z9 43 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 5 PY 1995 VL 237 IS 1-2 BP 14 EP 19 DI 10.1016/0009-2614(95)00269-A PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA QW527 UT WOS:A1995QW52700003 ER PT J AU CRUTZEN, PJ GROOSS, JU BRUHL, C MULLER, R RUSSELL, JM AF CRUTZEN, PJ GROOSS, JU BRUHL, C MULLER, R RUSSELL, JM TI A REEVALUATION OF THE OZONE BUDGET WITH HALOE UARS DATA - NO EVIDENCE FOR THE OZONE DEFICIT SO SCIENCE LA English DT Article ID VIBRATIONALLY EXCITED OXYGEN; LIMB INFRARED MONITOR; STRATOSPHERIC OZONE; MIDDLE ATMOSPHERE; PHOTOCHEMISTRY; MESOSPHERE; RADIATION; N2O AB Recently, additional ozone production mechanisms have been proposed to resolve the ozone deficit problem, which arises from greater ozone destruction than production in several photochemical models of the upper stratosphere and lower mesosphere. A detailed ozone model budget analysis was performed with simultaneous observations of O-3, HCl, H2O, CH4, NO, and NO2 from the Halogen Occultation Experiment (HALOE) an the Upper Atmosphere Research Satellite (UARS) under conditions with the strongest photochemical control of ozone. The results indicate that an ozone deficit may not exist. On the contrary, the use of currently recommended photochemical parameters leads to insufficient ozone destruction in the model. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. RP CRUTZEN, PJ (reprint author), MAX PLANCK INST CHEM,POB 3060,D-55020 MAINZ,GERMANY. RI Crutzen, Paul/F-6044-2012; Muller, Rolf/A-6669-2013; GrooSS, Jens-Uwe/A-7315-2013 OI Muller, Rolf/0000-0002-5024-9977; GrooSS, Jens-Uwe/0000-0002-9485-866X NR 36 TC 84 Z9 86 U1 0 U2 3 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 5 PY 1995 VL 268 IS 5211 BP 705 EP 708 DI 10.1126/science.268.5211.705 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QW603 UT WOS:A1995QW60300044 PM 17832384 ER PT J AU NEREM, RS AF NEREM, RS TI GLOBAL MEAN SEA-LEVEL VARIATIONS FROM TOPEX/POSEIDON ALTIMETER DATA SO SCIENCE LA English DT Article ID OCEAN; RISE AB The TOPEX/POSEIDON satellite altimeter mission has measured global mean sea level every 10 days over the last 2 years with a precision of 4 millimeters, which approaches the requirements for climate change research. The estimated rate of sea level change is +3.9 +/- 0.8 millimeters per year. A substantial portion of this trend may represent a short-term variation unrelated to the long-term signal expected from global warming. For this reason, and because the long-term measurement accuracy requires additional monitoring, a longer time series is necessary before climate change signals can be unequivocally detected. RP NEREM, RS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,CODE 926,GREENBELT,MD 20771, USA. NR 33 TC 35 Z9 35 U1 0 U2 4 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD MAY 5 PY 1995 VL 268 IS 5211 BP 708 EP 710 DI 10.1126/science.268.5211.708 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QW603 UT WOS:A1995QW60300045 PM 17832385 ER PT J AU PAPADI, GP BALAZS, GH JACOBSON, ER AF PAPADI, GP BALAZS, GH JACOBSON, ER TI FLOW CYTOMETRIC DNA CONTENT-ANALYSIS OF FIBROPAPILLOMAS IN GREEN TURTLES CHELONIA-MYDAS SO DISEASES OF AQUATIC ORGANISMS LA English DT Article DE FIBROPAPILLOMA; FLOW CYTOMETRY; GREEN TURTLE; CHELONIA MYDAS ID CUTANEOUS FIBROPAPILLOMAS AB In an attempt to characterize biologic properties of green turtle fibropapillomatosis (GTFP), blood cells, dermis of normal skin, dermis of cutaneous fibropapillomas, and visceral fibroblastic nodules of green turtles Chelonia mydas with cutaneous fibropapilloma were examined by flow cytometry. DNA of each sample was stained with propidium iodide and histograms were recorded utilizing a FACSCAN flow cytometer. All samples examined had similar histograms, indicative of normal cell cycles and diploid profiles. Small S phase and G(2)M fractions (<5%) indicated a low mitotic activity and a nonproliferating state. Statistical analyses were performed on the coefficient of variation (CV) of the G(1) peak for the various tissues analyzed. The mean CV for blood from all the unaffected turtles was 3.21 while that from turtles afflicted with GTFP was 3.43. CVs of normal skin from healthy turtles and turtles afflicted with GTFP were 4.25 and 4.41 respectively. The mean CV for fibropapillomas was 5.27, a number which, though higher than either blood or normal skin, probably reflects the difference in stain uptake characteristics between fibropapillomas and the other 2 tissues rather than any inherent DNA or ploidy difference. C1 UNIV FLORIDA,COLL VET MED,DEPT SMALL ANIM CLIN SCI,GAINESVILLE,FL 32610. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. RP PAPADI, GP (reprint author), UNIV FLORIDA,COLL VET MED,DEPT PATHOBIOL,GAINESVILLE,FL 32610, USA. NR 23 TC 2 Z9 2 U1 0 U2 0 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0177-5103 J9 DIS AQUAT ORGAN JI Dis. Aquat. Org. PD MAY 4 PY 1995 VL 22 IS 1 BP 13 EP 18 DI 10.3354/dao022013 PG 6 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA RB986 UT WOS:A1995RB98600002 ER PT J AU MAITRE, P BAUSCHLICHER, CW AF MAITRE, P BAUSCHLICHER, CW TI STRUCTURE OF V(H-2)(N)(+) CLUSTERS FOR N=1-6 SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID GAUSSIAN-BASIS SETS; TRANSITION-METAL ATOMS; MOLECULAR CALCULATIONS; BINDING-ENERGIES; ELECTRON CORRELATION; WAVE-FUNCTIONS; ROW ATOMS; SPIN; CONTRACTION; EXCHANGE AB Geometries, vibrational frequencies, spin states, H-2 binding energies, and Delta S values have been determined for V(H-2)(n)(+), for It = 1-6, using the B3LYP hybrid functional. The binding energies and Delta S values are in good agreement with experiment, thus showing that the B3LYP functional offers a reliable approach for optimizing the geometry and determining the H-2 binding energies for this system. The calculations show that the increase in the binding energy and entropy associated with the addition of the sixth H-2 to V+ is due to a change in spin state from quintet for the smaller clusters to triplet for V(H-2)(6)(+). The results for V(H-2)(n)(+) are compared with those for Co(H-2)(n)(+). C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Maitre, Philippe/C-1022-2013 OI Maitre, Philippe/0000-0003-2924-1054 NR 34 TC 39 Z9 39 U1 2 U2 2 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 MAY 4 PY 1995 VL 99 IS 18 BP 6836 EP 6841 DI 10.1021/j100018a014 PG 6 WC Chemistry, Physical SC Chemistry GA QW705 UT WOS:A1995QW70500014 ER PT J AU MCKAY, CP AF MCKAY, CP TI THE SNOWS OF OLYMPUS - A GARDEN ON MARS - CLARKE,AC SO NATURE LA English DT Book Review RP MCKAY, CP (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD MAY 4 PY 1995 VL 375 IS 6526 BP 26 EP 27 DI 10.1038/375026a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QW604 UT WOS:A1995QW60400042 ER PT J AU ZUG, GR BALAZS, GH WETHERALL, JA AF ZUG, GR BALAZS, GH WETHERALL, JA TI GROWTH IN JUVENILE LOGGERHEAD SEATURTLES (CARETTA-CARETTA) IN THE NORTH PACIFIC PELAGIC HABITAT SO COPEIA LA English DT Note ID SOUTHERN BAHAMAS; CHELONIA-MYDAS; GREEN TURTLES; SEA-TURTLES; RATES; AGE C1 NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,HONOLULU,HI 96822. RP ZUG, GR (reprint author), SMITHSONIAN INST,NATL MUSEUM NAT HIST,DEPT VERTEBRATE ZOOL,WASHINGTON,DC 20560, USA. NR 19 TC 39 Z9 46 U1 0 U2 6 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 SN 0045-8511 J9 COPEIA JI Copeia PD MAY 3 PY 1995 IS 2 BP 484 EP 487 PG 4 WC Zoology SC Zoology GA QX933 UT WOS:A1995QX93300028 ER PT J AU PALEY, MS FRAZIER, DO ABDELDEYEM, H ARMSTRONG, S MCMANUS, SP AF PALEY, MS FRAZIER, DO ABDELDEYEM, H ARMSTRONG, S MCMANUS, SP TI PHOTODEPOSITION OF AMORPHOUS POLYDIACETYLENE FILMS FROM MONOMER SOLUTIONS ONTO TRANSPARENT SUBSTRATES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DIACETYLENE; CRYSTALS; GENERATION AB Polydiacetylenes are a very promising class of polymers for both photonic and electronic applications because of their highly conjugated structures. For these applications, high-quality thin polydiacetylene films are required. We have discovered a novel technique for obtaining such films of a polydiacetylene derivative of 2-methyl-4-nitroaniline using photodeposition from monomer solutions onto UV transparent substrates. This heretofore unreported process yields amorphous polydiacetylene films with thicknesses on the order of 1 mu m that have optical quality superior to that of films grown by standard crystal growth techniques. Furthermore, these films exhibit good third-order nonlinear optical susceptibilities; degenerate four-wave mixing experiments give chi((3)) values on the order of 10(-8)-10(-7) esu. We have conducted masking experiments which demonstrate that photodeposition occurs only where the substrate is directly irradiated, clearly indicating that the reaction occurs at the surface. Additionally, we have also been able to carry out photodeposition using lasers to form thin polymer circuits. In this work, we discuss the photodeposition of polydiacetylene thin films from solution, perform chemical characterization of these films, investigate the role of the substrate, speculate on the mechanism of the reaction, and make a preliminary determination of the third-order optical nonlinearity of the films. This simple, straightforward technique may ultimately make feasible the production of polydiacetylene thin films for technological applications. C1 UNIV ALABAMA,MAT SCI PROGRAM,HUNTSVILLE,AL 35899. RP PALEY, MS (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 19 TC 29 Z9 29 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 3 PY 1995 VL 117 IS 17 BP 4775 EP 4780 DI 10.1021/ja00122a006 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA QW140 UT WOS:A1995QW14000006 ER PT J AU FREELAND, RE BILYEU, GD VEAL, GR AF FREELAND, RE BILYEU, GD VEAL, GR TI VALIDATION OF A UNIQUE CONCEPT FOR A LOW-COST, LIGHTWEIGHT SPACE-DEPLOYABLE ANTENNA STRUCTURE SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 44th Congress of the International-Astronautical-Federation CY OCT 16, 1993 CL GRAZ, AUSTRIA SP Int Astron Federat AB Large space-deployable antennas are needed for a variety of applications that include mobile communications, radiometry, active microwave sensing, very-long-baseline interferometry, DoD space-based radar and microspacecraft. Investigators in these fields identify the need for structures up to tens of meters in size for operation from 1 to 90 GHz, based on different aperture configurations. The selection criteria common to all of the users are low cost, lightweight, high reliability and good reflector surface precision. Fortunately, a unique class of space structures has recently emerged that offers great potential for satisfying these criteria. They are referred to as inflatable deployable structures. A good example of such a concept is under development at L'Garde Inc. Serious interest from the user community will depend on realistic demonstrations of the viability of the concept. This means that large, lightweight, low-cost structures need to be developed and used to demonstrate deployment reliability in realistic service environments. The technology data base for the L'Garde inflatable concept will accommodate the development of reflector antenna structures up to 30 m in diameter. Since the concept utilizes very low inflation pressure to maintain the required geometry on orbit, gravity-induced deflection of the structure precludes any meaningful ground-based demonstrations of functional performance. Therefore this concept has been selected for a NASA In-Space Technology Experiment Program (IN-STEP) space-based experiment. The objectives of this experiment are to validate and characterize the mechanical functional performance of a 14-m-diameter inflatable deployable reflector antenna structure in the orbital operational environment. The experiment will be carried by the NASA Spartan spacecraft, which is launched, deployed and recovered by the STS. The Spartan will provide mounting, attitude control, power and data recording for the antenna experiment. The antenna concept development will benefit from both the experiment and supporting technology developments. Results of this experiment are expected to verify the feasibility of fabricating a large space structure for only a few million dollars, demonstrate the reliability of deployment, characterize the quality of the reflector surface and correlate the analytical performance prediction models with actual measured characteristics. Technology developments in support of the experiment, to be conducted at NASA Langley Research Center and the University of Colorado, will include investigation of new and advanced flexible materials, as well as system studies to assess the adequacy of this structural concept for specific classes of applications and for the development of analytical performance production tools. These combined results will be used to advance the technology of the concept with respect to improving surface precision and performance predictability and accommodating larger size structures with different configurations in different orbits. RP FREELAND, RE (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 9 Z9 12 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 1995 VL 35 IS 9-11 BP 565 EP 572 DI 10.1016/0094-5765(95)00018-U PG 8 WC Engineering, Aerospace SC Engineering GA RK466 UT WOS:A1995RK46600002 ER PT J AU KLINE, EL AF KLINE, EL TI TECHNOLOGY AS A DRIVER FOR IMPROVED SPACE PRODUCTS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 44th Congress of the International-Astronautical-Federation CY OCT 16, 1993 CL GRAZ, AUSTRIA SP Int Astron Federat AB Technology development is frequently undertaken by research groups which are independent of program organizations, and then the difficult task is faced some time during program development of selecting the technology level which will meet the program's needs. This paper examines that process and suggests an approach which helps to establish the ''right'' technology level and conditions under which the technology will actually be introduced into the program. The paper recommends that a Technology Insertion Milestone be formally established to select the technologies or technology levels which will be incorporated during hardware development. The Technology Insertion Milestone should be a program event, and it should occur shortly before the design and development phase. Working with the program office, technology options can be presented and their payoff estimated for the program. Coupled with that appraisal should be a definition of the activity necessary to bring the technology options to the point where the program management would commit to its usage with confidence. This is a key point which should be part of the process. Examples are given of two NASA programs, Pluto Fast Flyby and TIMED, where the Technology Insertion Milestone process has been established and is underway. RP KLINE, EL (reprint author), NASA HEADQUARTERS, 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 MAY-JUN PY 1995 VL 35 IS 9-11 BP 601 EP 605 PG 5 WC Engineering, Aerospace SC Engineering GA RK466 UT WOS:A1995RK46600007 ER PT J AU LYONS, DT SAUNDERS, RS GRIFFITH, DG AF LYONS, DT SAUNDERS, RS GRIFFITH, DG TI THE MAGELLAN VENUS MAPPING MISSION - AEROBRAKING OPERATIONS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 44th Congress of the International-Astronautical-Federation CY OCT 16, 1993 CL GRAZ, AUSTRIA SP Int Astron Federat AB The orbit of the Magellan spacecraft was circularized during a 70-day aerobraking phase, which ended on 3 August 1993. Shrinking the orbit apoapsis from 8467 km down to 541 km was required to obtain meaningful gravity science data at high and moderate latitudes. Aerobraking was the only way to reach this nearly-circular orbit, since the amount of propellant on board Magellan was at least an order of magnitude too small to circularize propulsively. This paper will describe the steps taken by the Magellan flight team to successfully aerobrake the Magellan spacecraft into the nearly-circular orbit. Magellan is currently in a 541 by 197 km altitude orbit around the planet Venus. This paper will briefly describe the Magellan mission history and hardware, the goals of the continuing Magellan mission, the exciting aerobraking phase, and other science objectives beyond the primary continuing mission goal of producing a high-resolution global-gravity map of Venus. RP LYONS, DT (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 1995 VL 35 IS 9-11 BP 669 EP 676 DI 10.1016/0094-5765(95)00032-U PG 8 WC Engineering, Aerospace SC Engineering GA RK466 UT WOS:A1995RK46600014 ER PT J AU HUETER, U AF HUETER, U TI ACCESS-TO-SPACE - POTENTIAL FUTURE UNITED-STATES LAUNCH VEHICLE TRANSPORTATION SYSTEMS SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 44th Congress of the International-Astronautical-Federation CY OCT 16, 1993 CL GRAZ, AUSTRIA SP Int Astron Federat AB The existing unmanned launch vehicle fleet of the United States consists primarily of Delta, Atlas and Titan. The Space Shuttle is currently the only United States manned launch vehicle. Future launch system needs, both unmanned and manned, have recently been studied by various ''Blue Ribbon'' committees, as well as by both the National Aeronautics and Space Administration and the Department of Defense. The main impetus for investigating new ways of providing access to space is the aging launch vehicle fleet and the large costs associated with providing that access. Many options have been and are currently being investigated to provide the United States with a road map for charting the future path for access to space. The advent of a permanent international facility in space, Space Station, will dictate that routine and economical access be provided. This paper describes the systems being studied to improve the access to space by providing better, cheaper and more reliable launch systems capability. Architecture variations include both Space Shuttle improvements and phase-outs, new expendable launch vehicles, separate crew and cargo carriers and advanced technology crew and cargo RP HUETER, U (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD MAY-JUN PY 1995 VL 35 IS 9-11 BP 753 EP 761 DI 10.1016/0094-5765(95)00024-T PG 9 WC Engineering, Aerospace SC Engineering GA RK466 UT WOS:A1995RK46600022 ER PT J AU WIDEMAN, JK BROWN, JL MILES, JB OZCAN, O AF WIDEMAN, JK BROWN, JL MILES, JB OZCAN, O TI SKIN-FRICTION MEASUREMENTS IN 3-DIMENSIONAL, SUPERSONIC SHOCK-WAVE BOUNDARY-LAYER INTERACTION SO AIAA JOURNAL LA English DT Article AB The experimental documentation of a three-dimensional shock-wave/boundary-layer interaction in a nominal Mach 3 flow is presented. The model consisted of a sting-supported cylinder, aligned with the freestream flow, and a 20-deg half-angle conical hare offset 1.27 cm from the cylinder centerline. Surface oil flow, laser light sheet illumination, and spark schlieren photography were used to document the now topology. Extensive surface-pressure and skin-friction measurements were made throughout the interaction region. A laser interferometric skin-friction instrument was employed to acquire the skin-friction data. Resolved skin-friction measurements of C-fx and C-fz were made within the highly swept three-dimensional separated regions. The skin-friction data will be of particular value for turbulence modeling and computational fluid dynamics validation. C1 NASA,AMES RES CTR,MOLELING & EXPTL VALIDAT BRANCH,MOFFETT FIELD,CA 94035. ISTANBUL TECH UNIV,DEPT AERONAUT & ASTRONAUT,ISTANBUL 80626,TURKEY. RP WIDEMAN, JK (reprint author), UNIV MISSOURI,COLUMBIA,MO 65201, USA. NR 21 TC 9 Z9 9 U1 1 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 MAY PY 1995 VL 33 IS 5 BP 805 EP 811 DI 10.2514/3.12503 PG 7 WC Engineering, Aerospace SC Engineering GA QY557 UT WOS:A1995QY55700004 ER PT J AU CUTLER, AD LEVEY, BS KRAUS, DK AF CUTLER, AD LEVEY, BS KRAUS, DK TI NEAR-FIELD FLOW OF SUPERSONIC SWIRLING JETS SO AIAA JOURNAL LA English DT Article ID SHEAR-LAYER AB The addition of swirl to scramjet fuel jets has been proposed as a method of enhancing fuel mixing, but little of a fundamental nature is known about supersonic swirling flows. Several jets with different amounts of swirl were created by tangential injection and acceleration through a convergent-divergent nozzle. The flowfields near the nozzle exit were investigated using pitot, cone, and total-temperature probes, and Rayleigh scattering from a laser Light sheet. The results show that tangential injection is an efficient method for generating swirling jets, that the swirling jets mix much more rapidly with the stagnant air than comparable straight jets, and that, when overexpanded, turbulence is created in the jet core as a result of vortex breakdown. Mixing layer growth rates are shown to correlate with Richardson number. RP CUTLER, AD (reprint author), GEORGE WASHINGTON UNIV,NASA,JOINT INST ADV FLIGHT SCI,SCH ENGN & APPL SCI,HAMPTON,VA 23681, USA. NR 18 TC 19 Z9 19 U1 2 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 MAY PY 1995 VL 33 IS 5 BP 876 EP 881 DI 10.2514/3.12362 PG 6 WC Engineering, Aerospace SC Engineering GA QY557 UT WOS:A1995QY55700013 ER PT J AU JAUNKY, N KNIGHT, NF AMBUR, DR AF JAUNKY, N KNIGHT, NF AMBUR, DR TI BUCKLING OF ARBITRARY QUADRILATERAL ANISOTROPIC PLATES SO AIAA JOURNAL LA English DT Article ID SKEW PLATES AB The problem of buckling of arbitrary quadrilateral anisotropic plates with different boundary conditions under combined in-plane loading is considered. A Rayleigh-Ritz method combined with a variational formulation and a first-order transverse-shear-deformation theory is used. The Ritz functions consist of polynomials which include ''circulation'' functions that impose various boundary conditions. Numerical results are obtained for isotropic, orthotropic, and anisotropic plates with skewed geometries and are compared with existing results that use series solutions and with results generated from finite element simulations. C1 NASA,LANGLEY RES CTR,DIV STRUCT,STRUCT MECH BRANCH,HAMPTON,VA 23681. RP JAUNKY, N (reprint author), OLD DOMINION UNIV,DEPT AEROSP ENGN,NORFOLK,VA 23529, USA. NR 20 TC 28 Z9 31 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1995 VL 33 IS 5 BP 938 EP 944 DI 10.2514/3.12512 PG 7 WC Engineering, Aerospace SC Engineering GA QY557 UT WOS:A1995QY55700023 ER PT J AU MURTHY, DV PIERRE, C OTTARSSON, G AF MURTHY, DV PIERRE, C OTTARSSON, G TI EFFICIENT DESIGN CONSTRAINT ACCOUNTING FOR MISTUNING EFFECTS IN ENGINE ROTORS SO AIAA JOURNAL LA English DT Note C1 UNIV MICHIGAN,DEPT MECH ENGN & APPL MECH,ANN ARBOR,MI 48109. NASA,LEWIS RES CTR,DIV STRUCT,CLEVELAND,OH 44135. RP MURTHY, DV (reprint author), UNIV TOLEDO,DEPT ENGN MECH,TOLEDO,OH 44135, USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 1995 VL 33 IS 5 BP 960 EP 962 DI 10.2514/3.12663 PG 3 WC Engineering, Aerospace SC Engineering GA QY557 UT WOS:A1995QY55700031 ER PT J AU MIKOUCHI, T TAKEDA, H MIYAMOTO, M OHSUMI, K MCKAY, GA AF MIKOUCHI, T TAKEDA, H MIYAMOTO, M OHSUMI, K MCKAY, GA TI EXSOLUTION LAMELLAE OF KIRSCHSTEINITE IN MAGNESIUM-IRON OLIVINE FROM AN ANGRITE METEORITE SO AMERICAN MINERALOGIST LA English DT Article ID CRYSTAL AB Exsolution phenomena of kirschsteinite (CaFeSiO4) in olivine have been studied by single-crystal X-ray diffraction techniques and scanning electron microscopy (SEM) of oriented polished thin sections (PTS) of three single crystals separated from the Antarctic angrite LEW86010, supplemented by micro-area X-ray diffraction with the Laue method (MXL) by synchrotron radiation (SR) for PTS of a rock chip of LEW86010. The cell dimensions of the host olivine and exsolved kirschsteinite are a = 4.79(3), b = 10.39(5), and c = 6.06(3) Angstrom, and a = 4.87(5), b = 11.14(10), and c = 6.36(5) Angstrom, respectively, from the precession photos. The PTS of olivine single crystals oriented parallel to (100) show exsolution lamellae of kirschsteinite up to 10 mu m in width. The two sets of lamellae are symmetrically related and parallel to (031) and (0(3) over bar1$). Electron microprobe analysis gave SiO2 33.1, TiO2 0.07, Al2O3 0.03, FeO 49.4, MnO 0.61, MgO 13.4, CaO 2.2, Cr2O3 0.02, V2O3 0.01, NiO 0.05 (sum 99.4 wt%) for the host olivine and SiO2 33.3, TiO2 0.03, FeO 31.5, MnO 0.39, MgO 5.4, CaO 28.5, Cr2O3 0.02, NiO 0.05 (sum 99.2 wt%) for the exsolved kirschsteinite. The results from MXL for the olivine crystals on the rock PTS are compatible with the observation on the single crystals that the lamellae are parallel to (031) and (0(3) over bar1$). The (031) and (0(3) over bar1$) planes have been known to be twin planes for olivine, and the twinning is by reticular pseudomerohedry based on a quadruple lattice. Although other reported exsolved precipitates in meteoritic olivines exist as inclusions, kirschsteinite in LEW86010 olivine takes the form of lamellae. Our explanation is that LEW86010 olivine is Fe-rich and that lamellar precipitates are more easily formed than inclusions because exsolution lamellae along {031} in Fe-rich olivine maintain lattice coherency. C1 KEK,NATL LAB HIGH ENERGY PHYS,PHOTON FACTORY,TSUKUBA,IBARAKI 305,JAPAN. NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058. RP MIKOUCHI, T (reprint author), UNIV TOKYO,GRAD SCH SCI,INST MINERAL,TOKYO 113,JAPAN. NR 37 TC 21 Z9 21 U1 1 U2 8 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1130 17TH ST NW SUITE 330, WASHINGTON, DC 20036 SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 1995 VL 80 IS 5-6 BP 585 EP 592 PG 8 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA RF781 UT WOS:A1995RF78100017 ER PT J AU RUSSELL, WS AF RUSSELL, WS TI POLYNOMIAL INTERPOLATION SCHEMES FOR INTERNAL DERIVATIVE DISTRIBUTIONS ON STRUCTURED GRIDS SO APPLIED NUMERICAL MATHEMATICS LA English DT Article DE NUMERICAL INTERPOLATION; FINITE DIFFERENCE APPROXIMATIONS; ERROR ANALYSIS; N-BODY CALCULATIONS; OCEAN CURRENTS ID SIMULATIONS; GALAXIES AB Computational fluid dynamics problems which use a streamfunction formulation require differentiation to obtain the velocity field. If the velocity components are required at internal points on the grid (for example, for particle trajectory calculations) this necessitates some form of interpolation. Similarly, N-body computations which include self-gravity and cannot afford the luxury of an O(N-2) 1/r(2) calculation, require interpolation to obtain the force components at locations internal to an overlaid grid. These two independent examples reduce to the same generalized problem. Given a function distribution on a structured grid, which interpolation schemes give the most suitable solutions in terms of accuracy, computational efficiency and smoothness properties? The best numerical schemes are those which use higher order finite difference approximations for the derivatives (but not vast templates), perform interpolation directly over the derivative (and not the function), and have an odd power as the leading term in the polynomial expansion for the derivative. These methods include forms of bicubic and quintic-cubic interpolation but although generating accurate and realistic internal derivative estimates, come at a higher computational price. For simulations where the interpolation routines need to be called frequently, the lower order schemes such as cubic-linear and biquadratic interpolation, although less accurate, are more computationally efficient and may be more appropriate. C1 NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP COLUMBIA UNIV, DEPT APPL PHYS, 2880 BROADWAY, NEW YORK, NY 10025 USA. NR 15 TC 15 Z9 15 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 EI 1873-5460 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 1995 VL 17 IS 2 BP 129 EP 171 DI 10.1016/0168-9274(95)00014-L PG 43 WC Mathematics, Applied SC Mathematics GA RE232 UT WOS:A1995RE23200004 ER PT J AU NAMIOKA, T KOIKE, M AF NAMIOKA, T KOIKE, M TI ASPHERIC WAVE-FRONT RECORDING OPTICS FOR HOLOGRAPHIC GRATINGS SO APPLIED OPTICS LA English DT Article DE HOLOGRAPHIC GRATING; ASPHERIC GRATING; ABERRATIONS; MONOCHROMATOR; SPECTROGRAPH ID DIFFRACTION GRATINGS AB The geometric theory of aspheric wave-front recording optics is extended to include the fourth-order groove parameters that correspond to the fourth-order holographic terms in the light-path function. We derived explicit expressions of the groove parameters by analytically following an exact ray-tracing procedure for a double-element optical system that consists of a point source, an ellipsoidal mirror, and an ellipsoidal grating blank. Design examples of holographic gratings for an in-plane Eagle-type vacuum-UV monochromator are given to demonstrate the capability of the present theory in the design of aspheric wave-front recording optics. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720. NR 10 TC 49 Z9 67 U1 1 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD MAY 1 PY 1995 VL 34 IS 13 BP 2180 EP 2186 PG 7 WC Optics SC Optics GA QW018 UT WOS:A1995QW01800003 PM 21037764 ER PT J AU RAMANI, R RAMACHANDRA, P RAVICHANDRAN, TSG RAMAGOPAL, G GOPAL, S RANGANATHAIAH, C AF RAMANI, R RAMACHANDRA, P RAVICHANDRAN, TSG RAMAGOPAL, G GOPAL, S RANGANATHAIAH, C TI MICROSTRUCTURE OF POLYCARBONATE SEEN BY POSITRONS AS AN IN-SITU PROBE SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article ID CURED EPOXY POLYMERS; FREE-VOLUME; SEMICRYSTALLINE PEEK; ANNIHILATION; POLYACRYLONITRILE; DEPENDENCE; SYSTEMS AB Positron Annihilation Lifetime Spectroscopy (PALS) is used to probe the micro-structural changes in the polymer polycarbonate in terms of the changes in free volume hole size and their content as a function of temperature. The measured spectra are best fitted to three lifetime component analysis. The average hole size in the amorphous regions is determined from the measured Ortho Positronium (O-Ps) lifetime tau(3) by following the treatment of Nakanishi et al. On the other hand, information about defects in the crystalline regions is revealed by trapped positrons lifetime tau(2). In this polymer the average hole radius varies from 2.71 A to 2.77 Angstrom. The present study indicates that this polymer has a glass transition temperature of 152 degrees C. Further, we have calculated the trapping rates in the ordered and disordered regions of the polymer based on Goldanskii's kinetic equations and an attempt is made for the first time to estimate the activation energy in the amorphous and crystalline regions separately. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP RAMANI, R (reprint author), UNIV MYSORE,DEPT STUDIES PHYS,MYSORE 570006,KARNATAKA,INDIA. NR 31 TC 25 Z9 25 U1 1 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0721-7250 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD MAY PY 1995 VL 60 IS 5 BP 481 EP 486 DI 10.1007/BF01538773 PG 6 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA QY566 UT WOS:A1995QY56600009 ER PT J AU KOERNER, DW SARGENT, AI AF KOERNER, DW SARGENT, AI TI IMAGING THE SMALL-SCALE CIRCUMSTELLAR GAS AROUND T-TAURI STARS SO ASTRONOMICAL JOURNAL LA English DT Article ID YOUNG STELLAR OBJECTS; MODEL SCATTERING ENVELOPES; HL-TAURI; RADIAL-VELOCITIES; CIRCUMBINARY DISK; MOLECULAR CLOUD; R-MONOCEROTIS; GG-TAURI; AURIGA; POLARIZATION C1 CALTECH,DIV PHYS MATH & ASTRON,PASADENA,CA 91125. RP KOERNER, DW (reprint author), CALTECH,JET PROP LAB,169-506,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 48 TC 103 Z9 103 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1995 VL 109 IS 5 BP 2138 EP 2145 DI 10.1086/117439 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV645 UT WOS:A1995QV64500021 ER PT J AU GRAPS, AL SHOWALTER, MR LISSAUER, JJ KARY, DM AF GRAPS, AL SHOWALTER, MR LISSAUER, JJ KARY, DM TI OPTICAL DEPTH PROFILES AND STREAMLINES OF THE URANIAN EPSILON-RING SO ASTRONOMICAL JOURNAL LA English DT Article ID OCCULTATION C1 SUNY STONY BROOK,DEPT EARTH & SPACE SCI,ASTRON PROGRAM,STONY BROOK,NY 11794. STANFORD UNIV,CTR RADAR ASTRON,STANFORD,CA 94305. RP GRAPS, AL (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035, USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 1995 VL 109 IS 5 BP 2262 EP 2273 DI 10.1086/117451 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV645 UT WOS:A1995QV64500033 ER PT J AU MITROFANOV, IG POZANENKO, AS CHERNENKO, AM FISHMAN, J KOUVELIOTOU, K MEAGAN, C PACIESAS, W SAGDEEV, RZ AF MITROFANOV, IG POZANENKO, AS CHERNENKO, AM FISHMAN, J KOUVELIOTOU, K MEAGAN, C PACIESAS, W SAGDEEV, RZ TI STATISTICAL-ANALYSIS OF FLUX VARIABILITY AND ENERGY-SPECTRA OF COSMIC GAMMA-RAY BURSTS OBSERVED WITH BATSE EXPERIMENT OF COMPTON OBSERVATORY SO ASTRONOMICHESKII ZHURNAL LA Russian DT Article AB The results of statistical study of flux variability and energy spectra of 260 cosmic gamma-ray bursts in the First catalog of BATSE experiment of COMPTON observatory are presented. It is shown that an averaged flux time history of the bursts has a one-peak asymmetric shape with steep rising front and a longer decay. Averaged hardness ratio of energy spectra is at maximum at the rising front, and decreases monotonically over the decay part of the averaged time history profile. Comparison of averaged flux time history profiles of two distinct sets of ''stronger'' and ''weaker'' bursts has shown that they match closely. On the other hand, the profiles of averaged hardness ratios are widely different: on the average, the stronger bursts are harder than the weaker ones. On the grounds of the observation results, a test of cosmological model of cosmic gamma-ray bursts was carried out. A close match of the averaged profiles of ''strong'' and ''weak'' gamma- ray bursts is at odds with that model: a double or triple broadening of profiles of ''weak'' bursts, predicted by the cosmological model, cannot be compensated for by the fact that due to the reddening of photons, the profiles of ''weak'' bursts correspond to higher energies of radiated photons having shorter peaks on the flux time history profiles. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. UNIV MARYLAND,COLLEGE PK,MD 20741. RP MITROFANOV, IG (reprint author), MOSCOW SPACE RES INST,MOSCOW 117810,RUSSIA. NR 14 TC 2 Z9 2 U1 0 U2 0 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0004-6299 J9 ASTRON ZH+ JI Astron. Zhurnal PD MAY-JUN PY 1995 VL 72 IS 3 BP 344 EP 352 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RJ500 UT WOS:A1995RJ50000007 ER PT J AU HARRISON, TE MCNAMARA, BJ PEDERSEN, H JORGENSEN, HE HELT, BE GREEN, DA KORANYI, DM WARNER, PJ WALDRAM, EM RYAN, J KIPPEN, RM HANLON, L HERMSEN, W BENNETT, K SCHONFELDER, V PALMER, DM BOER, M POLLAS, C METLOV, VG METLOVA, NV VYSKOCIL, L WENZEL, W WEBER, T HUDEC, R FRAIL, DA KULKARNI, SR FISHMAN, GJ KOUVELIOTOU, C MEEGAN, CA OLSEN, ET LEVIN, S WANNIER, PG JANSSEN, MA MAHONEY, WA BARTHELMY, SD CLINE, TL GEHRELS, N AF HARRISON, TE MCNAMARA, BJ PEDERSEN, H JORGENSEN, HE HELT, BE GREEN, DA KORANYI, DM WARNER, PJ WALDRAM, EM RYAN, J KIPPEN, RM HANLON, L HERMSEN, W BENNETT, K SCHONFELDER, V PALMER, DM BOER, M POLLAS, C METLOV, VG METLOVA, NV VYSKOCIL, L WENZEL, W WEBER, T HUDEC, R FRAIL, DA KULKARNI, SR FISHMAN, GJ KOUVELIOTOU, C MEEGAN, CA OLSEN, ET LEVIN, S WANNIER, PG JANSSEN, MA MAHONEY, WA BARTHELMY, SD CLINE, TL GEHRELS, N TI PRELIMINARY-RESULTS FROM THE GROUND-BASED BATSE/COMPTEL/NMSU RAPID RESPONSE NETWORK FOR GRB-940301 SO ASTRONOMY & ASTROPHYSICS LA English DT Note DE GAMMA-RAYS, BURSTS ID MHZ SKY SURVEY AB The origins of gamma-ray bursts still remain unknown more than 20 years after their discovery. Since burst durations at gamma-ray energies last, on average, only a few seconds, efforts at identifying the source of the bursts have concentrated on followup observations at lower energies. To investigate whether gamma-ray bursts do emit lower-energy radiation shortly after the burst event, networks of ground-based observatories have been established to search the fields of gamma-ray bursts as soon as the position of the burst is reasonably well localized. We report the preliminary results of multi-wavelength observations from the BATSE/COMPTEL/NMSU Rapid Response Network for GRB 940301. Radio observations of the burst position began within one hour of the burst detection. Optical images of the COMPTEL error box were first obtained seven hours after the burst. The ground-based optical and radio observations continued for several weeks after the burst. A small number of variable stars, and several radio sources were found inside the gamma-ray burst error box. We cannot, however, conclusively determine whether any of these objects were responsible for GRB 940301. The multi-wavelength observations we report can be used to impose limits to constrain future models for the origin of gamma-ray bursts. C1 COPENHAGEN UNIV OBSERV, DK-1350 COPENHAGEN, DENMARK. CAVENDISH LAB, MULLARD RADIO ASTRON OBSERV, CAMBRIDGE CB3 0HE, ENGLAND. UNIV NEW HAMPSHIRE, CTR SPACE SCI, DURHAM, NH 03824 USA. EUROPEAN SPACE TECHNOL CTR, DIV ASTROPHYS, 2200 AG NOORDWIJK, NETHERLANDS. SRON, 3584 CA UTRECHT, NETHERLANDS. MAX PLANCK INST EXTRATERR PHYS, D-85748 MUNICH, GERMANY. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. CTR ETUD SPATIALE RAYONNEMENTS, CNRS, UPS, F-31029 TOULOUSE, FRANCE. OBSERV CALERN, OBSERV COTE AZUR, F-06460 ST VALLIER DE THIEY, FRANCE. PK STERNBERG ASTRONM INST, CRIMEAN LAB, CRIMEA 334413, UKRAINE. UPICE OBSERV, CR-54232 UPICE, CZECH REPUBLIC. SONNEBERG OBSERV, D-96515 SONNEBERG, GERMANY. INST ASTRON, CR-25165 ONDREJOV, CZECH REPUBLIC. NATL RADIO ASTRON OBSERV, SOCORRO, NM 87801 USA. CALTECH, DIV PHYS MATH & ASTRON 10524, PASADENA, CA 91125 USA. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35899 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP HARRISON, TE (reprint author), NEW MEXICO STATE UNIV, BOX 30001, DEPT 4500, LAS CRUCES, NM 88003 USA. RI Gehrels, Neil/D-2971-2012; Green, David/E-9609-2010; Barthelmy, Scott/D-2943-2012; Hudec, Rene/G-9018-2014 OI Green, David/0000-0003-3189-9998; NR 15 TC 3 Z9 3 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAY PY 1995 VL 297 IS 2 BP 465 EP 469 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY554 UT WOS:A1995QY55400034 ER PT J AU CARPENTER, KG ROBINSON, RD JUDGE, PG AF CARPENTER, KG ROBINSON, RD JUDGE, PG TI GHRS OBSERVATIONS OF COOL, LOW-GRAVITY STARS .2. FLOW AND TURBULENT VELOCITIES IN THE OUTER ATMOSPHERE OF GAMMA-CRU-CIS(M3.4-III) SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, CHROMOSPHERES; STARS, INDIVIDUAL (GAMMA CRU) CIS; STARS, LATE-TYPE; TURBULENCE ULTRAVIOLET, STARS ID EMISSION-LINES; FE-II; CHROMOSPHERES; EXCITATION AB The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope has been used to obtain medium (R = 20,000) and high (R = 85,000) resolution UV spectra of chromospheric emission features for the M3.4 III star gamma Cru. Small Science Aperture (SSA) G270M and Echelle-B spectra of selected regions in the 2300-2850 Angstrom range were obtained to determine the kinematics of the chromosphere using lines of C II], Fe II, Co II, Si I/II], Ni rr, Mn II, and Mg II. Profiles of C II] (UV 0.01) lines and fluorescently excited lines of low optical depth indicate average turbulent velocities (Doppler FWHM) of 30.2 +/- 1.3 and 28.8 +/- 1.3 km s(-1), respectively. The fluorescent emission lines (mean RV = 21.3 +/- 0.9 km s(-1)) and the wings of the emission components of Fe II lines (mean RV = 22.8 +/- 0.4 km s(-1)) are approximately at rest relative to the radial velocity of the star (21 km s(-1)), while the C II] lines show a modest inflow (mean RV = 23.1 +/- 0.9 km s(-1)). The more opaque lines of Fe II and Mg Ir exhibit complex profiles resulting from line formation in an optically thick, extended expanding atmosphere. The emission wings of these lines are broadened by multiple scattering, and they are centered near the photospheric radial velocity. Closer to line center, these strong lines show a strong blueshifted self-absorption feature (already seen in IUE data), indicative of formation in an expanding chromosphere, and a previously unseen dip in the profiles on the red side of line center. The absorption components, when extracted using simple Gaussian fits, show strong correlations with the relative optical depths of the lines. The derived absorption flow velocities converge to the photospheric velocity as one examines spectral features formed deeper in the atmosphere. The blueward absorption velocity increases in magnitude from about 7 to 14 km s(-1) with increasing line optical depth-the strong absorptions directly map the acceleration of the outflowing stellar wind, while the interpretation of the weaker redshifted absorptions is more ambiguous, indicating either an inflow of material or formation in an extended, spherically expanding outflow. The Mg It and Fe II profiles, taken together, imply that the wind speed decreases between the atmospheric layers where the Mg II and Fe II self-absorption components are formed. Interstellar absorptions are seen in the resonance lines of Mg II (UV 1) and Fe Ir (UV 1) with zero-volt lower levels, at about -3 km s(-1), consistent with models of the interstellar medium in the direction of gamma Cru. Finally, we have detected the Mg Ir ''satellite lines'' seen in solar spectra obtained above the limb. In gamma Cru these lines are probably fluorescently excited by H Ly beta. C1 NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,ASTRON PROGRAM,GREENBELT,MD 20771. NATL CTR ATMOSPHER RES,HIGH ALTITUDE OBSERV,BOULDER,CO 80307. RP CARPENTER, KG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 681,GREENBELT,MD 20771, USA. RI Carpenter, Kenneth/D-4740-2012 NR 28 TC 20 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 MAY 1 PY 1995 VL 444 IS 1 BP 424 EP 437 DI 10.1086/175617 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV080 UT WOS:A1995QV08000040 ER PT J AU WAHLGREN, GM LECKRONE, DS JOHANSSON, SG ROSBERG, M BRAGE, T AF WAHLGREN, GM LECKRONE, DS JOHANSSON, SG ROSBERG, M BRAGE, T TI THE ABUNDANCES OF PT, AU, AND HG IN THE CHEMICALLY PECULIAR HGMN-TYPE STARS KAPPA-CANCRI AND CHI-LUPI SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, ABUNDANCES; STARS, CHEMICALLY PECULIAR; STARS, INDIVIDUAL (KAPPA CANCRI, CHI LUPI); ULTRAVIOLET, SPECTRA ID HIGH-RESOLUTION SPECTROGRAPH; S-PROCESS NUCLEOSYNTHESIS; SINGLY-IONIZED PLATINUM; ADDED IUE SPECTRA; NORMAL LATE-B; ELEMENTAL ABUNDANCES; CROSS-SECTIONS; MAIN-SEQUENCE; ENERGY-LEVELS; SOLAR AB Echelle mode spectra obtained with the Goddard High Resolution Spectrograph onboard the Hubble Space Telescope have been used to determine the abundances of the heavy elements Pt, Au, and Hg in the chemically peculiar HgMn-type stars kappa Cancri and chi Lupi. The abundances were determined by fitting observed line profiles with synthetically generated spectra and are found to be enhanced relative to solar system values by between three and five orders of magnitude in both stars. The Hg isotope mixture in kappa Cancri is found to resemble the terrestrial mixture while that of chi Lupi is dominated by the heaviest isotope. As determined from multiple ionization states, the abundances place constraints upon theories attempting to explain the large surficial abundances of heavy elements. C1 NASA,GODDARD SPACE FLIGHT CTR,GHRS SCI TEAM,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. LUND UNIV,DEPT PHYS,S-22362 LUND,SWEDEN. NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,GREENBELT,MD 20771. RP WAHLGREN, GM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,COMP SCI CORP,ASTRON PROGRAM,CODE 681,GREENBELT,MD 20771, USA. NR 86 TC 46 Z9 47 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 1995 VL 444 IS 1 BP 438 EP 451 DI 10.1086/175618 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV080 UT WOS:A1995QV08000041 ER PT J AU OFMAN, L DAVILA, JM AF OFMAN, L DAVILA, JM TI CORONAL HEATING BY THE RESONANT ABSORPTION OF ALFVEN WAVES - WAVE-NUMBER SCALING LAWS SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; SUN, CORONA; SUN, MAGNETIC FIELDS; WAVES ID NON-UNIFORM PLASMA; SURFACE-WAVES; SOLAR CORONA; NORMAL-MODES; RESISTIVE MAGNETOHYDRODYNAMICS; EFFICIENCY; DYNAMICS; DECAY; LOOPS; IDEAL AB The importance of global modes in coronal loop heating is well established. In the present work the scaling of the global-mode resonant heating rate with the perturbation wavenumbers is studied with the numerical solution of the linearized time-dependent MHD equations for a full compressible, low-beta, resistive plasma using an implicit integration scheme. The numerical simulations demonstrate that the dissipation on inhomogeneities in the background Alfven speed occurs in narrow resonant layer with the highest heating rate at the global-mode frequency. The global-mode heating rate H-r was found to scale as H-r similar to k(y)(-1.03) when k(z) = 0.1, and as H-r similar to k(y)(-1.93) when k(z) = 0.75, where k(y) and k(z) are the wavenumbers in the perpendicular and parallel to the magnetic field directions, respectively, while the dependence of H-r on k(z) is more complex. The ''quality factor'' Q of the MHD resonance cavity scales as Q similar to k(y)(-1.8) for k(z) = 0.75 and as Q similar to k(y)(-1.46) for k(z) = 0.1 The numerically determined heating rate scaling, the global-mode frequency, and the ''quality factor'' are in good agreement with the analytical linear theory. The magnitude of the perturbed velocities was found to decrease with k(y). Assuming typical coronal loop parameters (B-0 = 100-200 G, upsilon(A) 2000-4000 km s(-1)), the Alfven waves can supply the required heating in a low-Q loops. C1 SW RES INST, DEPT SPACE SCI, SAN ANTONIO, TX 78228 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, GREENBELT, MD 20771 USA. NR 39 TC 70 Z9 70 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 MAY 1 PY 1995 VL 444 IS 1 BP 471 EP 477 DI 10.1086/175621 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QV080 UT WOS:A1995QV08000044 ER PT J AU KIM, DC SANDERS, DB VEILLEUX, S MAZZARELLA, JM SOIFER, BT AF KIM, DC SANDERS, DB VEILLEUX, S MAZZARELLA, JM SOIFER, BT TI OPTICAL SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES .1. NUCLEAR-DATA SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE GALAXIES, STELLAR CONTENT; INFRARED, GALAXIES ID NARROW-LINE REGION; IRAS OBSERVATIONS; SEYFERT-GALAXIES; SAMPLE AB A spectroscopic survey of a large sample of luminous infrared galaxies [log(L(ir)/L.)(7) similar or equal to 10.5-12.5; H-0 = 75 km s(-1) Mpc(-1)] has been carried out using the Palomar 5 m telescope and the University of Hawaii 2.2 m telescope. Long-slit spectra covering 3750-8000 Angstrom at a resolution of similar to 10 Angstrom were obtained of 200 IRAS galaxies, including 114 objects from the IRAS Bright Galaxy Survey, and 86 objects with fainter infrared fluxes selected on the basis of their ''warm'' far-infrared (S-60/S-100) colors. The methods of observation and data reduction are discussed. An atlas of the spectra extracted from the nuclear region of these objects is presented along with a large number of parameters describing the properties of the emission lines, the stellar absorption lines, and the continuum emission that were measured from the spectra. An analysis of these data is presented in a companion paper (Veilleux et al. 1995) along with a discussion of the spatial variations of these parameters in a subsample of twenty-three objects. C1 NATL OPT ASTRON OBSERV,KITT PEAK NATL OBSERV,PASADENA,CA 91125. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. CALTECH,PALOMAR OBSERV,DOWNS LAB,PASADENA,CA 91125. CALTECH,CTR INFRARED PROC & ANAL,JET PROPULS LAB,PASADENA,CA 91125. RP KIM, DC (reprint author), UNIV HAWAII,INST ASTRON,2680 WOODLAWN DR,HONOLULU,HI 96822, USA. NR 31 TC 158 Z9 158 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 1995 VL 98 IS 1 BP 129 EP 170 DI 10.1086/192157 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU868 UT WOS:A1995QU86800006 ER PT J AU VEILLEUX, S KIM, DC SANDERS, DB MAZZARELLA, JM SOIFER, BT AF VEILLEUX, S KIM, DC SANDERS, DB MAZZARELLA, JM SOIFER, BT TI OPTICAL SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES .2. ANALYSIS OF THE NUCLEAR AND LONG-SLIT DATA SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE GALAXIES, ACTIVE; GALAXIES, NUCLEI; GALAXIES, STELLAR CONTENT; H II REGIONS; INFRARED, GALAXIES ID H-II-REGIONS; ACTIVE GALACTIC NUCLEI; JET-INDUCED VELOCITIES; EMISSION-LINE SPECTRA; INITIAL MASS FUNCTION; STAR-FORMATION RATES; SEYFERT-GALAXIES; IRAS GALAXIES; DISK GALAXIES; SPIRAL GALAXIES AB A spectroscopic survey of a sample of 200 luminous IRAS galaxies (LIGs: L(ir)(7) > 3 X 10(10) L.; H-0 = 75 km s(-1) Mpc(-1)) was carried out using the Palomar 5 meter and University of Hawaii 2.2 m telescopes. Kim et al. (1995) described the data-taking and data-reduction procedures and presented line and continuum measurements extracted from the nucleus of these objects. In this paper, the nuclear data are combined with circumnuclear measurements on 23 of these galaxies to investigate the properties of the line-emitting gas and underlying stellar population in and out of the nucleus. The nuclear spectra of these galaxies were classified as ''H II region-like'' or ''AGN-like'' using a large number of line-ratio diagnostics corrected for the underlying stellar absorption features. This correction is an important source of errors in some previous studies. The emission-line spectra of many AGNs were found to be of relatively low ionization level and were therefore classified as LINER. We confirm that both the fraction of LIGs with AGN spectra and the fraction of Seyferts among the AGN increase with infrared luminosity, reaching values of 62% and 54% at the highest observed luminosities, respectively. The fraction of LINERs, on the other hand, is relatively constant at similar to 27%. The source of the ionization of the emission-line gas often is a function of the distance from the nucleus. Based on the emission-line ratios and the strengths of the stellar absorption features, circumnuclear starburst activity is a common feature of LIGs, regardless of their nuclear spectral types. The emission-line, absorption-line, continuum, radio, and IRAS properties of the LINERs suggest that most of the LINER emission in these infrared-selected galaxies is produced through shock ionization rather than photoionization by a genuine active nucleus. The nuclear region of Seyfert LIGs is found to be slightly less reddened than that of the LINERs and H II galaxies. The dust distribution generally is concentrated toward the nucleus, in agreement with the often peaky distribution of the molecular gas observed in these galaxies. Inverted dust profiles in which the nucleus appears less dusty than the circumnuclear region are observed in only three LIGs, all of which have AGN emission-line characteristics (one Seyfert 2 galaxy and two LINERs). Low nuclear dust content appears to favor the detection of active nuclei. This may be due to selection effects or may reflect real physical differences between these classes of objects: galaxies with Seyfert emission lines may be at a more advanced stage of dust destruction/expulsion than H II LIGs. Complex optical depth effects may also explain these results without invoking a smaller amount of dust in the nucleus. The H beta and Mg I b absorption features are stronger in the nuclei of AGNs (especially among the LINERs) than in H II LIGs, suggesting that AGN LIGs are at a more advanced stage of stellar evolution than H II LIGs. Further support for this scenario comes from the fact that AGNs are found more frequently in advanced mergers than H II galaxies (only two Seyfert galaxies are detected in systems with well-separated nuclei). However, this last result may be a luminosity effect rather than an effect related to the dominant nuclear source of ionization. Moreover, the absorption-line data may simply reflect the fact that galaxies with powerful H II regions show evidence for young stars while galaxies with AGNs do not. The radial variations of the HP and Mg I b absorption features indicate the presence of a strong source of featureless continuum in the nucleus of nearly all LIGs, regardless of their nuclear spectral types. Contamination by the circumnuclear starburst prevents us from determining the extent of this continuum source. The [O III] profiles of both Seyfert and LINER LIGs were found to be broader on average than those of H II objects. Nearly 20% of the LIGs in our sample have line widths larger than 600 km s(-1). We find that most of the galaxies in which we could determine the radial variations of the [O III] line width present broader profiles in the circumnuclear region than at the nucleus. When combined with published data on a few other well-studied LIGs, these results suggest that large-scale nuclear winds are common in these objects and are an efficient way of getting rid of the obscuring material in the nuclear region. The spatially extended LINER emission observed in many of these objects is probably due to shock ionization resulting from the interaction of the wind-accelerated gas with the ambient material of the host galaxy. C1 UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. UNIV HAWAII,ASTRON INST,HONOLULU,HI 96822. CALTECH,CTR INFRARED PROC & ANAL,JET PROPULS LAB,PASADENA,CA 91125. CALTECH,PALOMAR OBSERV,PASADENA,CA 91125. RP VEILLEUX, S (reprint author), KITT PEAK NATL OBSERV,NATL OPT ASTRON OBSERV,POB 26732,TUCSON,AZ 85726, USA. NR 207 TC 479 Z9 481 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 1995 VL 98 IS 1 BP 171 EP 217 DI 10.1086/192158 PG 47 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU868 UT WOS:A1995QU86800007 ER PT J AU CABOT, W THOMPSON, KW POLLACK, JB AF CABOT, W THOMPSON, KW POLLACK, JB TI NUMERICAL SIMULATIONS OF STRATIFIED COMPRESSIBLE CONVECTION WITH INTERNAL HEATING AND DISK-LIKE VARIABLE GRAVITY SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE CONVECTION; HYDRODYNAMICS; METHODS, NUMERICAL; SOLAR SYSTEM, FORMATION; STARS, FORMATION; TURBULENCE ID DEPENDENT BOUNDARY-CONDITIONS; PRIMORDIAL SOLAR NEBULA; TURBULENT CONVECTION; SUPERSONIC CONVECTION; HYPERBOLIC SYSTEMS; ROTATION; MODEL; LAYER; TRANSPORT; EVOLUTION AB Numerical hydrodynamic simulations of three-dimensional, turbulent, fully compressible thermal convection have been performed for an internally heated layer with varying degrees of density and temperature stratification as a preliminary study of realistic convection in the primordial solar nebula and other protostellar disks. Gravity is made to vary linearly as distance from the midplane, approximating the conditions in thin, gaseous protostellar disks. These simulations have been performed in a periodic channel at unrealistically low Reynolds numbers in order to resolve all relevant scales of turbulent motion; and differential rotation, another important feature of protostellar disks, has not been included. In this paper we describe the numerical techniques used to perform the hydrodynamic simulations; we examine the convective now structure and turbulence statistics; and we discuss the effects of compressibility and stratification on the turbulent convection. The turbulence (rms) Mach numbers M(t) in the central convective regions are found to be less than or similar to 0.25, and acoustic terms, scaling as M(t)(2), are found to be negligible except near (unrealistic) solid boundaries. Near these walls, there is enhanced compression and rapid tangential flow, which sometimes becomes supersonic and exhibits weak shocks. Temperature deviations of less than 25% from the mean in horizontal planes are typically observed. Density stratification is shown to have significant effects on the convection, primarily due to increased thermal diffusivity in the outer, more rarefied regions, which (1) reduces the efficiency of convective heat transport, and (2) can stabilize the gas against convection in the outermost regions. Some simulation results are presented in which the convection is realistically bounded by convectively stable regions that effectively buffer the interior convective flow from the physically unrealistic boundaries. Significant overshooting of convective motions into the stable region is observed, but, because of the inefficient nature of this convection, little penetration of convective layer into the stable layer is observed. The stable layer acts as a ''soft wall'' with less enhancement of compression and horizontal velocities, making supersonic flow and shocks unlikely in turbulent now driven solely by convection in protostellar disks. C1 NASA,AMES RES CTR,DIV SPACE SCI,MOFFETT FIELD,CA 94035. RP CABOT, W (reprint author), STANFORD UNIV,CTR TB RES,BLDG 500,STANFORD,CA 94305, USA. NR 39 TC 5 Z9 5 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 1995 VL 98 IS 1 BP 315 EP 343 DI 10.1086/192163 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU868 UT WOS:A1995QU86800012 ER PT J AU BHATIA, AK DOSCHEK, GA AF BHATIA, AK DOSCHEK, GA TI ATOMIC DATA AND SPECTRAL-LINE INTENSITIES FOR FE-X SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID CROSS-SECTIONS; EXCITATION; IONS; IRON AB Electron impact collision strengths and spontaneous radiative decay rates are calculated for the important astrophysical ion Fe X. The data pertain to the 54 levels of the configurations 3s(2)3p(5), (3)s(3)P(6) 3s(2)3p(4)3d, and 3s3p(5)3d. Collision strengths are calculated at five incident electron energies: 9.0, 18.0, 27.0, 36.0, and 45.0 Ry. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients( cm(3)s(-1)), i.e., the collision strengths integrated over a Maxwellian electron energy distribution, and then solving the equations of detailed balance for the populations of the 54 energy levels, assuming a collisional excitation model and an electron temperature of 1.0 X 10(6) K. This temperature is typical for Fe X when formed in. equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are given in this paper. We also investigate the effects of proton excitation and solar radiative excitation on the level populations and line intensities. Finally, the calculated relative line intensities are compared with experimental solar intensities where available, and two good electron-density-sensitive line ratios are discussed. One result of the comparison is the identification of four unidentified solar spectral lines as Fe X transitions: 220.86, 226.32, 238.71, and 324.71 Angstrom. (C) 1995 Academic Press, Inc. C1 USN,RES LAB,EO HULBURT CTR SPACE RES,WASHINGTON,DC 20375. RP BHATIA, AK (reprint author), GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 21 TC 66 Z9 66 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAY PY 1995 VL 60 IS 1 BP 97 EP 143 DI 10.1006/adnd.1995.1005 PG 47 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA QZ246 UT WOS:A1995QZ24600003 ER PT J AU BHATIA, AK DOSCHEK, GA AF BHATIA, AK DOSCHEK, GA TI ATOMIC DATA AND SPECTRAL-LINE INTENSITIES FOR C-LIKE MG-VII SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID OPTICALLY ALLOWED TRANSITIONS; CROSS-SECTIONS; EXCITATION; IONS AB Electron impact collision strengths and spontaneous radiative decay rates are calculated for the C-like ion Mg VII. The data pertain to the 46 levels of the configurations 2s(2)2p(2), 2s2p(3), 2p(4), 2s(2)2p3S, 2s(2)2p3p, and 2s(2)2p3d, Collision strengths are calculated at three incident electron energies: 12.0, 24.0, and 36.0 Ry. Spectral line intensities are calculated for all transitions with intensities within two orders of magnitude of the most intense Mg VII line. These are obtained by computing the excitation rate coefficients (cm(3) s(-1)), i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 46 energy levels, assuming a collisional excitation model and an electron temperature of 6.31 X 10(5) K. This temperature is typical for Mg VII in solar and some other astrophysical plasmas. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities and are also given in this paper. (C) 1995 Academic Press. Inc. C1 USN,RES LAB,EO HULBURT CTR SPACE RES,WASHINGTON,DC 20375. RP BHATIA, AK (reprint author), GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771, USA. NR 13 TC 19 Z9 19 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAY PY 1995 VL 60 IS 1 BP 145 EP 173 DI 10.1006/adnd.1995.1006 PG 29 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA QZ246 UT WOS:A1995QZ24600004 ER PT J AU SICONOLFI, SF LEMOINE, SL AF SICONOLFI, SF LEMOINE, SL TI GRADED-EXERCISE TESTING FOR SPACEFLIGHT SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID BED-REST; CAPACITY AB We developed and validated a graded exercise protocol suitable for operational use on space station. The new treadmill protocol has three level-grade stages (3-min each) at 70, 80, and 90% of estimated VO(2)peak. The protocol maintains the third stage speed while grade increases each minute to produce work rates equivalent to 100, 107, and 115% of the estimated VO(2)peak. We compared the new protocol's peak and submaximal responses to those observed during a NASA graded exercise test. All mean protocol differences, including peak work rate (-1.8%), VO(2)peak (-6.4%), HRpeak (-2.4%), and VEpeak (-9.7%), were not significantly different from the expected measurement errors. We observed similar results for indices (the oxygen uptake at a HR of 150 and the HR's at 70, 80, and 90% of VO(2)peak) of the submaximal HR-VO2 relationship, The new protocol is an acceptable graded exercise test for periodic operational fitness tests. C1 LOUISIANA TECH UNIV,RUSTON,LA 71270. RP SICONOLFI, SF (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST SD5,HOUSTON,TX 77058, USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD MAY PY 1995 VL 66 IS 5 BP 435 EP 439 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA QX391 UT WOS:A1995QX39100007 PM 7619037 ER PT J AU MONTGOMERY, LD MONTGOMERY, RW GUISADO, R AF MONTGOMERY, LD MONTGOMERY, RW GUISADO, R TI RHEOENCEPHALOGRAPHIC AND ELECTROENCEPHALOGRAPHIC MEASURES OF COGNITIVE WORKLOAD - ANALYTICAL PROCEDURES SO BIOLOGICAL PSYCHOLOGY LA English DT Article DE COGNITIVE WORKLOAD; EEG; REG; HEMODYNAMIC CHANGES; ANALYTICAL PROCEDURES; ENERGY-DENSITY DISTRIBUTIONS ID CEREBRAL BLOOD-FLOW AB This investigation demonstrates the feasibility of mental workload assessment by rheoencephalographic (REG) and multichannel electroencephalographic (EEG) monitoring. During the performance of this research, unique testing, analytical and display procedures were developed for REG and EEG monitoring that extend the current state of the art and provide valuable tools for the study of cerebral circulatory and neural activity during cognition. REG records are analyzed to provide indices of the right and left hemisphere hemodynamic changes that take place during each test sequence. The EEG data are modeled using regression techniques and mathematically transformed to provide energy-density distributions of the scalp electrostatic field. These procedures permit concurrent REG/EEG cognitive testing not possible with current techniques. The introduction of a system for recording and analysis of cognitive REG/EEG test sequences facilitates the study of learning and memory disorders, dementia and other encephalopathies. C1 NASA,AMES RES CTR,BIONET CORP,MOFFETT FIELD,CA 94035. CTR NEURODIANOST STUDY INC,SAN JOSE,CA 95119. NR 35 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0511 J9 BIOL PSYCHOL JI Biol. Psychol. PD MAY PY 1995 VL 40 IS 1-2 BP 143 EP 159 DI 10.1016/0301-0511(95)05117-1 PG 17 WC Psychology, Biological; Behavioral Sciences; Psychology; Psychology, Experimental SC Psychology; Behavioral Sciences GA RB501 UT WOS:A1995RB50100010 PM 7647176 ER PT J AU POPE, AT BOGART, EH BARTOLOME, DS AF POPE, AT BOGART, EH BARTOLOME, DS TI BIOCYBERNETIC SYSTEM EVALUATES INDEXES OF OPERATOR ENGAGEMENT IN AUTOMATED TASK SO BIOLOGICAL PSYCHOLOGY LA English DT Article DE CLOSED-LOOP FEEDBACK; EEG; EMG; MANUAL AUTOMATED SYSTEM; ATTENTIONAL CAPABILITY ID EEG AB A biocybernetic system has been developed as a method to evaluate automated flight deck concepts for compatibility with human capabilities. A biocybernetic loop is formed by adjusting the mode of operation of a task set (e.g., manual/automated mix) based on electroencephalographic (EEG) signals reflecting an operator's engagement in the task set. A critical issue for the loop operation is the selection of features of the EEG to provide an index of engagement upon which to base decisions to adjust task mode. Subjects were run in the closed-loop feedback configuration under four candidate and three experimental control definitions of an engagement index. The temporal patterning of system mode switching was observed for both positive and negative feedback of the index. The indices were judged on the basis of their relative strength in exhibiting expected feedback control system phenomena (stable operation under negative feedback and unstable operation under positive feedback). Of the candidate indices evaluated in this study, an index constructed according to the formula, beta power/(alpha power + theta power), reflected task engagement best. C1 LOCKHEED ENGN & SCI CO,HAMPTON,VA 23666. RP POPE, AT (reprint author), NASA,LANGLEY RES CTR,MS 152,HAMPTON,VA 23681, USA. NR 9 TC 139 Z9 141 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0511 J9 BIOL PSYCHOL JI Biol. Psychol. PD MAY PY 1995 VL 40 IS 1-2 BP 187 EP 195 DI 10.1016/0301-0511(95)05116-3 PG 9 WC Psychology, Biological; Behavioral Sciences; Psychology; Psychology, Experimental SC Psychology; Behavioral Sciences GA RB501 UT WOS:A1995RB50100013 PM 7647180 ER PT J AU SKILES, JW AF SKILES, JW TI MODELING CLIMATE-CHANGE IN THE ABSENCE OF CLIMATE-CHANGE DATA SO CLIMATIC CHANGE LA English DT Note ID ATMOSPHERIC CARBON-DIOXIDE; CO2; SIMULATION; CIRCULATION; STREAMFLOW; CYCLE; EVAPOTRANSPIRATION; SENSITIVITY; SCENARIOS; INCREASE RP SKILES, JW (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV,MAIL STOP 239-20,MOFFETT FIELD,CA 94035, USA. NR 38 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1995 VL 30 IS 1 BP 1 EP 6 DI 10.1007/BF01093222 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RC884 UT WOS:A1995RC88400001 ER PT J AU VANBLARCUM, SC MILLER, JR RUSSELL, GL AF VANBLARCUM, SC MILLER, JR RUSSELL, GL TI HIGH-LATITUDE RIVER RUNOFF IN A DOUBLED CO2 CLIMATE SO CLIMATIC CHANGE LA English DT Article ID ATMOSPHERIC CO2; MODEL; SENSITIVITY; INCREASE; BASIN AB A global atmospheric model is used to calculate the monthly river flow for nine of the world's major high latitude 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 model's runoff from each grid box is quartered and added to the appropriate river drainage basin on a 2 degrees x 2.5 degrees resolution. A routing scheme is used to move runoff from a grid box to its neighboring downstream grid box and ultimately to the mouth of the river. In a model simulation in which atmospheric carbon dioxide is doubled, mean annual precipitation and river flow increase for all of these rivers, increased outflow at the river mouths begins earlier in the spring, and the maximum outflow occurs approximately one month sooner due to an earlier snow melt season. In the doubled CO2 climate, snow mass decreases for the Yukon and Mackenzie rivers in North America and for rivers in northwestern Asia, but snow mass increases for rivers in northeastern Asia. C1 RUTGERS STATE UNIV,COOK COLL,DEPT MARINE & COASTAL SCI,NEW BRUNSWICK,NJ 08903. NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025. RP VANBLARCUM, SC (reprint author), USAF,OSS 16,OGSW,HURLBURT FIELD,FL 32544, USA. NR 26 TC 12 Z9 12 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1995 VL 30 IS 1 BP 7 EP 26 PG 20 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RC884 UT WOS:A1995RC88400002 ER PT J AU CHRISTY, JR SPENCER, RW AF CHRISTY, JR SPENCER, RW TI ASSESSMENT OF PRECISION IN TEMPERATURES FROM THE MICROWAVE SOUNDING UNITS SO CLIMATIC CHANGE LA English DT Note ID RADIOSONDE VALIDATION; ANOMALIES; MODEL; MSU C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP CHRISTY, JR (reprint author), UNIV ALABAMA,HUNTSVILLE,AL 35899, USA. NR 19 TC 14 Z9 14 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1995 VL 30 IS 1 BP 97 EP 102 DI 10.1007/BF01093227 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RC884 UT WOS:A1995RC88400006 ER PT J AU HANSEN, J WILSON, H SATO, M RUEDY, R SHAH, K HANSEN, E AF HANSEN, J WILSON, H SATO, M RUEDY, R SHAH, K HANSEN, E TI SATELLITE AND SURFACE-TEMPERATURE DATA AT ODDS SO CLIMATIC CHANGE LA English DT Note ID AIR-TEMPERATURE; TRENDS; MODEL RP HANSEN, J (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 28 TC 49 Z9 50 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1995 VL 30 IS 1 BP 103 EP 117 DI 10.1007/BF01093228 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA RC884 UT WOS:A1995RC88400007 ER PT J AU KIM, SW AF KIM, SW TI NUMERICAL INVESTIGATION OF CHEMICAL-REACTION TURBULENCE INTERACTION IN COMPRESSIBLE SHEAR LAYERS SO COMBUSTION AND FLAME LA English DT Article ID CROSS-FLOW; MODEL; FLAMES AB Calculations of mixing of hydrogen and vitiated supersonic airstream with and without chemical reactions are presented. The Favre-averaged compressible flow equations and convection-diffusion equations for the chemical species are solved by a finite volume method that incorporates an incremental pressure equation for the conservation of mass. The chemical reactions are described by 9 chemical species and 24 pairs of reaction-steps. The turbulence field is described by multiple-time-scale turbulence equations. The calculated ignition delay and species concentrations obtained using the multiple-time-scale turbulence equations are in closer agreement with the measured data than those obtained using a probability density function method and k-epsilon turbulence models. It is shown that the multiple-time-scale turbulence equations successfully predict the increased shear layer thickness caused by the chemical reaction-turbulence interaction. RP KIM, SW (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 32 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAY PY 1995 VL 101 IS 3 BP 197 EP 208 DI 10.1016/0010-2180(94)00198-2 PG 12 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA QW029 UT WOS:A1995QW02900001 ER PT J AU COHEN, BI BARNES, DC DAWSON, JM HAMMETT, GW LEE, WW KERBEL, GD LEBOEUF, JN LIEWER, PC TAJIMA, T WALTZ, RE AF COHEN, BI BARNES, DC DAWSON, JM HAMMETT, GW LEE, WW KERBEL, GD LEBOEUF, JN LIEWER, PC TAJIMA, T WALTZ, RE TI THE NUMERICAL TOKAMAK PROJECT - SIMULATION OF TURBULENT TRANSPORT SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID GYROKINETIC PARTICLE SIMULATION; DRIFT INSTABILITIES; TOROIDAL GEOMETRY; FLUID MODELS AB Three-dimensional fluid and kinetic models are being used to simulate the turbulent confinement of energy and plasma in the core of tokamaks. These simulations represent a qualitative improvement in the realism with which they model large tokamak experiments, because they use realistic plasma parameters and incorporate important geometrical effects. The combination of algorithm improvements and the application of high-performance computing methodology including the use of massively parallel computers has enabled dramatic improvements in simulation capability. A consortium of research groups from universities and national laboratories are collaborating in this effort which is entitled the Numerical Tokamak Project and is supported in part by the High Performance Computing and Communications Initiative. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08540. LAWRENCE LIVERMORE NATL LAB,NATL ENERGY RES SUPERCOMP CTR,LIVERMORE,CA 94550. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. CALTECH,JET PROP LAB,PASADENA,CA 91109. UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712. GEN ATOM CO,SAN DIEGO,CA 92186. RP COHEN, BI (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Hammett, Gregory/D-1365-2011 OI Hammett, Gregory/0000-0003-1495-6647 NR 46 TC 17 Z9 17 U1 0 U2 4 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 MAY PY 1995 VL 87 IS 1-2 BP 1 EP 15 DI 10.1016/0010-4655(94)00166-Y PG 15 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RB389 UT WOS:A1995RB38900002 ER PT J AU WANG, J LIEWER, P DECYK, V AF WANG, J LIEWER, P DECYK, V TI 3D ELECTROMAGNETIC PLASMA PARTICLE SIMULATIONS ON A MIMD PARALLEL COMPUTER SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article AB A three-dimensional electromagnetic PIC code has been developed on the 512 node Intel Touchstone Delta MIMD parallel computer. This code uses a standard relativistic leapfrog scheme to push particles and a local finite-difference time-domain method to update the electromagnetic fields. The code is implemented using the General Concurrent PIC algorithm which uses a domain decomposition to divide the computation among the processors. The 3D simulation domain can be partitioned into 1-, 2-, or 3-dimensional subdomains. Particles must be exchanged between processors as they move among the subdomains, The Intel Delta allows one to use this code for very-large-scale simulations (i.e. over 10(8) particles and 10(6) grid cells). The parallel efficiency of this code is measured, and the overall code performance on the Delta is compared with that on Gray supercomputers. It is shown that our code runs with a high parallel efficiency of greater than or equal to 95% for large size problems. The particle push time achieved is 115 ns/particle/time step for 162 million particles on 512 nodes. Compared with the performance on a single CPU Gray C90, this represents a factor of 58 speedup. It is also shown that the finite-difference method for the field solve is significantly more efficient than transform methods on parallel computers. The field solve time is < 0.7% of total time for problems with 77 particles/cell, and it is < 3% even for problems with 7 particles/cell. C1 UNIV CALIF LOS ANGELES,LOS ANGELES,CA. RP WANG, J (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 16 TC 32 Z9 33 U1 0 U2 2 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 MAY PY 1995 VL 87 IS 1-2 BP 35 EP 53 DI 10.1016/0010-4655(94)00167-Z PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RB389 UT WOS:A1995RB38900004 ER PT J AU DECYK, VK AF DECYK, VK TI SKELETON PIC CODES FOR PARALLEL COMPUTERS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID PLASMA AB Simple skeleton particle-in-cell codes designed for massively parallel computers are described. These codes are used to develop new algorithms and evaluate new parallel computers. Benchmark results from a number of MIMD parallel computers are presented. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RP DECYK, VK (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYS,405 HILGARD AVE,LOS ANGELES,CA 90024, USA. NR 9 TC 41 Z9 41 U1 1 U2 4 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 MAY PY 1995 VL 87 IS 1-2 BP 87 EP 94 DI 10.1016/0010-4655(94)00169-3 PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RB389 UT WOS:A1995RB38900006 ER PT J AU BENZ, W ASPHAUG, E AF BENZ, W ASPHAUG, E TI SIMULATIONS OF BRITTLE SOLIDS USING SMOOTH PARTICLE HYDRODYNAMICS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID IMPACT; FAILURE AB We describe a version of the smooth particle hydrodynamics (SPH) method suitable for modeling solids. The model includes strength and implements a von Mises yielding relation for stresses beyond the Hugoniot elastic limit. At lower stresses associated with brittle failure we use a rate-dependent strength based on the nucleation and growth of explicit Weibull flaws. We illustrate the capabilities of our fracture model by examining the propagation of cracks in a simple tensile rod, and by comparing simulations with laboratory experiments for high speed impacts and cratering. C1 UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP BENZ, W (reprint author), UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721, USA. NR 21 TC 182 Z9 203 U1 0 U2 16 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 MAY PY 1995 VL 87 IS 1-2 BP 253 EP 265 DI 10.1016/0010-4655(94)00176-3 PG 13 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA RB389 UT WOS:A1995RB38900016 ER PT J AU REDDY, DR AF REDDY, DR TI 3-D NAVIER-STOKES ANALYSIS OF CROSSING GLANCING SHOCKS TURBULENT BOUNDARY-LAYER INTERACTIONS SO COMPUTERS & FLUIDS LA English DT Article AB Three-dimensional viscous Row analysis is performed for a configuration where two crossing and glancing shocks interact with a turbulent boundary layer. A time marching 3-D full Navier-Stokes code, called PARC3D, is used to compute the flow field and the solution is compared to the experimental data obtained at the NASA Lewis Research Center 1 ft x 1 ft supersonic wind tunnel facility. The study is carried out as part of the continuing code assessment program in support of the Generic Hypersonic Research at NASA Lewis. Detailed comparison of static pressure fields and oil flow patterns is made with the corresponding solution on the wall containing the shock/boundary layer interaction in an effort to validate the code for hypersonic inlet applications. RP REDDY, DR (reprint author), NASA,LEWIS RES CTR,MAIL STOP 5-11,CLEVELAND,OH 44135, USA. NR 22 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 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD MAY PY 1995 VL 24 IS 4 BP 435 EP 445 DI 10.1016/0045-7930(94)00035-W PG 11 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA QX702 UT WOS:A1995QX70200007 ER PT J AU VANDERSANDE, JW ZOLTAN, LD AF VANDERSANDE, JW ZOLTAN, LD TI USING HIGH-TEMPERATURE ELECTRICAL-RESISTIVITY MEASUREMENTS TO DETERMINE THE QUALITY OF DIAMOND FILMS SO DIAMOND AND RELATED MATERIALS LA English DT Article; Proceedings Paper CT 5th European Conference on Diamond, Diamond-Like and Related Materials (Diamond Films 94) CY SEP 25-30, 1994 CL IL CIOCCO, ITALY DE ELECTRICAL CONDUCTIVITY; ELECTRICAL PROPERTIES ID CONDUCTIVITY AB The electrical resistivity of undoped diamond films has been measured between room temperature and 1200 degrees C. The films were grown by either microwave plasma CVD or combustion flame at various different companies. It was found that the room temperature resistivities were all around 10(15)-10(16)Omega cm, which has been shown to be the apparatus-limited value (higher resistivities cannot be measured). Hence these resistivity measurements cannot indicate which of the films, which all have very similar Raman spectra, are of the best quality. Also, the sample treatment (such as as-fabricated, heat treated, cleaned) will affect the room temperature electrical resistivity because of different surface conditions. On the other hand, high-temperature measurements up to 1200 degrees C clearly do show differences for samples that have the same electrical resistivity at room temperature. The high-temperature resistivities varied from about one order of magnitude lower than that for natural type IIa diamond to about two orders of magnitude greater over the whole temperature range, with activation energies between 1.5 and 1.6 eV. These high-temperature measurements are thus very helpful in determining the quality of undoped diamond films. RP VANDERSANDE, JW (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 5 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0925-9635 J9 DIAM RELAT MATER JI Diam. Relat. Mat. PD MAY 1 PY 1995 VL 4 IS 5-6 BP 641 EP 644 DI 10.1016/0925-9635(94)05218-2 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA QV435 UT WOS:A1995QV43500019 ER PT J AU JUREWICZ, SR JONES, JH FEGLEY, B AF JUREWICZ, SR JONES, JH FEGLEY, B TI EXPERIMENTAL PARTITIONING OF ZR, NB, AND TI BETWEEN PLATINUM-GROUP METALS AND SILICATE LIQUID - IMPLICATIONS FOR THE ORIGIN OF REFRACTORY-METAL NUGGETS IN CARBONACEOUS CHONDRITES SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article ID TEMPERATURE THERMODYNAMIC PROPERTIES; ALLENDE METEORITE; SOLAR NEBULA; CA,AL-RICH INCLUSION; OPAQUE ASSEMBLAGES; RICH INCLUSIONS; CHEMISTRY; SYSTEMS; CONDENSATION; ELEMENTS AB Reports of percent level concentrations of normally lithophile elements such as Zr, Nb, and Ta in some refractory noble metal nuggets in CAIs raise important questions about the redox state of the early solar nebula. Consequently, we have determined the metal/silicate liquid partition coefficients for Zr, Nb, and Ti at 1548 K and solar oxygen fugacity (fo(2) similar to 10(-16) bar). In most experiments, these elements formed intermetallic compounds with Pt-metal. Even though our partition coefficients for Zr (2.06-4.55) were substantially greater than previously determined values, they are still too small to account for percent levels of Zr in a refractory metal nugget from an average CAI. In addition, partition coefficient values obtained for Nb and Ti show an extremely strong affinity for the metal phase. Yet, Nb, is rarely observed in refractory metal nuggets and Ti has never been observed. Given the abundance of Ti in CAIs, substantial concentrations of Ti should be present in refractory metal nuggets. This discrepancy is attributed to either: (1) the solar fo(2) was too oxidizing during condensation to form the predicted intermetallic compounds; or (2) the lithophile elements originally formed intermetallic compounds with Pt-metals during condensation in the solar nebula but were subsequently oxidized in a latter heating event. Whereas our experiments suggest that conditions were never reducing enough for Ti to alloy with Pt metal, other redox determinations (e.g. Ti3+/Ti4+ ratios in CAI) imply approximately solar oxygen fugacities. Our experiments serve to emphasize the range in redox states implied by metal and silicate assemblages in CAI. C1 NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058. WASHINGTON UNIV,DEPT EARTH & PLANETARY SCI,ST LOUIS,MO 63130. WASHINGTON UNIV,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130. NR 47 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD MAY PY 1995 VL 132 IS 1-4 BP 183 EP 198 DI 10.1016/0012-821X(95)00068-N PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RE226 UT WOS:A1995RE22600015 ER PT J AU BIKLE, DD HARRIS, J HALLORAN, BP CURRIER, PA TANNER, S MOREYHOLTON, E AF BIKLE, DD HARRIS, J HALLORAN, BP CURRIER, PA TANNER, S MOREYHOLTON, E TI THE MOLECULAR RESPONSE OF BONE TO GROWTH-HORMONE DURING SKELETAL UNLOADING - REGIONAL DIFFERENCES SO ENDOCRINOLOGY LA English DT Article ID OSTEOBLAST-LIKE CELLS; FACTOR-I; SIMULATED WEIGHTLESSNESS; COLLAGEN-SYNTHESIS; HYPOPHYSECTOMIZED RATS; ALKALINE-PHOSPHATASE; MINERAL METABOLISM; GH THERAPY; SHORT-TERM; IGF-I AB Hind limb elevation of the growing rat provides a good model for the skeletal changes that occur during space flight. In this model the bones of the forelimbs (normally loaded) are used as an internal control for the changes that occur in the unloaded bones of the hind limbs. Previous studies have shown that skeletal unloading of the hind limbs results in a transient reduction of bone formation in the tibia and femur, with no change in the humerus. This fall in bone formation is accompanied by a fall in serum osteocalcin (bone Gla protein, BGP) and bone BGP messenger RNA (mRNA) levels, but a rise in bone insulin-like growth factor-I (IGF-I) protein and mRNA levels and resistance to the skeletal growth-promoting actions of IGF-I. To determine whether skeletal unloading also induced resistance to GH, we evaluated the response of the femur and humerus of sham and hypophysectomized rats, control and hind limb elevated, to GH (two doses), measuring mRNA levels of IGF-I, BGP, rat bone alkaline phosphatase (RAP), and alpha(1)(1)-procollagen (cell). Hypophysectomy (HPX) decreased the mRNA levels ofIGF-I, BGP, and cell in the femur, but was either less effective or had the opposite effect in the humerus. GH at the higher dose (500 mu g/day) restored these mRNA levels to or above the sham control values in the femur, but generally had little or no effect on the humerus. RAP mRNA levels were increased by HPX, especially in the femur. The lower dose of GH (50 mu g/day) inhibited this rise in RAP, whereas the higher dose raised the mRNA levels and resulted in the appearance of additional transcripts not seen in controls. As for the other mRNAs, RAP mRNA in the humerus was less affected by HPX or GH than that in the femur. Hind limb elevation led to an increase in IGF-I, cell, and RAP mRNAs and a reduction in BGP mRNA in the femur and either had no effect or potentiated the response of these mRNAs to GH. We conclude that GH stimulates a number of markers of bone formation by raising their mRNA levels, and that skeletal unloading does not block this response, but the response varies substantially from bone to bone. C1 UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94121. UNIV CALIF SAN FRANCISCO,DEPT PHYSIOL,SAN FRANCISCO,CA 94121. NASA,AMES RES CTR,DIV BIOMED RES,MOFFETT FIELD,CA 94035. RP BIKLE, DD (reprint author), VET ADM MED CTR,DIV ENDOCRINOL,4150 CLEMENT ST,SAN FRANCISCO,CA 94121, USA. NR 51 TC 31 Z9 32 U1 0 U2 1 PU ENDOCRINE SOC PI BETHESDA PA 4350 EAST WEST HIGHWAY SUITE 500, BETHESDA, MD 20814-4110 SN 0013-7227 J9 ENDOCRINOLOGY JI Endocrinology PD MAY PY 1995 VL 136 IS 5 BP 2099 EP 2109 DI 10.1210/en.136.5.2099 PG 11 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA QU628 UT WOS:A1995QU62800041 PM 7720659 ER PT J AU MCLACHLAN, BG BELL, JH AF MCLACHLAN, BG BELL, JH TI PRESSURE-SENSITIVE PAINT IN AERODYNAMIC TESTING SO EXPERIMENTAL THERMAL AND FLUID SCIENCE LA English DT Article; Proceedings Paper CT 3rd World Conference on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics CY OCT 31-NOV 05, 1993 CL HONOLULU, HI SP AMER SOC MECH ENGINEERS, AMER INST CHEM ENGINEERS, NATL COMM HEAT & MASS TRANSFER, RUSSIA, SOC CHEM ENGINEERS, JAPAN, REG CTR ENERGY HEAT & MASS TRANSFER ASIA & PACIFIC DE AERODYNAMIC MEASUREMENT TECHNIQUE; SURFACE PRESSURE MEASUREMENT; PRESSURE SENSITIVE PAINT; PRESSURE INDICATING PAINT; PHOTOLUMINESCENCE OXYGEN QUENCHING ID LUMINESCENT AB Pressure-sensitive paint (PSP) is a relatively new aerodynamic measurement tool with the unique capability of providing a field measurement of pressure over a test surface. An introductory review of this technology is presented, which is confined to the application of the PSP method to aircraft development wind tunnel testing. This is at present the primary application area and thus the focus of research on the use of the method, and is the authors' own area of research. Described are PSP fundamentals, the various elements comprising PSP technology, and current limitations and considerations in applying this technology. Experimental results are presented to illustrate the present capability of the method. The few publications currently available on this subject in the open literature are also referenced. RP MCLACHLAN, BG (reprint author), NASA,AMES RES CTR,ADV AERODYNAM CONCEPTS BRANCH,MAIL STOP 227-2,MOFFETT FIELD,CA 94035, USA. NR 25 TC 89 Z9 92 U1 0 U2 7 PU ELSEVIER SCIENCE PUBL CO INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0894-1777 J9 EXP THERM FLUID SCI JI Exp. Therm. Fluid Sci. PD MAY PY 1995 VL 10 IS 4 BP 470 EP 485 DI 10.1016/0894-1777(94)00123-P PG 16 WC Thermodynamics; Engineering, Mechanical; Physics, Fluids & Plasmas SC Thermodynamics; Engineering; Physics GA QY649 UT WOS:A1995QY64900006 ER PT J AU KOBAYASHI, DR KAWAMOTO, KE AF KOBAYASHI, DR KAWAMOTO, KE TI EVALUATION OF SHARK, DOLPHIN, AND MONK SEAL INTERACTIONS WITH NORTHWESTERN HAWAIIAN ISLAND BOTTOMFISHING ACTIVITY - A COMPARISON OF 2 TIME PERIODS AND AN ESTIMATE OF ECONOMIC-IMPACTS SO FISHERIES RESEARCH LA English DT Article DE BOTTOMFISHERIES; DOLPHIN; ECONOMICS; MONK SEAL; PREDATION; SHARK AB The incidence rates of bottomfish damaged by sharks, dolphins, and monk seals were compared from two sources of observer data taken aboard commercial bottomfishing vessels in the Northwestern Hawaiian islands. The current (1990-1993) shark damage rate is significantly different from, and nearly six times higher than, the rate measured in 1981-1982. The dolphin and monk seal damage rates are also currently higher than the earlier rates. These temporal differences could be indicative of an increasing trend in interaction rates. A theoretical model is developed to estimate unobservable losses of fish based on the amount of fishing gear lost. The current economic impact is estimated to be approximately $700,000 annually (or approximately $7000 of lost revenue per trip on average) considering all sources of losses. RP KOBAYASHI, DR (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 0 TC 1 Z9 2 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD MAY PY 1995 VL 23 IS 1-2 BP 11 EP 22 DI 10.1016/0165-7836(94)00338-W PG 12 WC Fisheries SC Fisheries GA RA549 UT WOS:A1995RA54900002 ER PT J AU MACMILLAN, DS AF MACMILLAN, DS TI ATMOSPHERIC GRADIENTS FROM VERY LONG-BASE-LINE INTERFEROMETRY OBSERVATIONS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LINE INTERFEROMETRY; RADIO AB Azimuthal asymmetries in the atmospheric refractive index can lead to errors in estimated vertical and horizontal station coordinates. Generally these gradients are not modeled in standard very long baseline interferometry (VLBI) geodetic analysis. Daily average gradient effects can be as large as 50 mm of delay at a 7 degrees elevation. To model gradients, the constrained estimation of gradient parameters was added to the standard VLBI solution procedure. Here the analysis of two sets of data is summarized: the set of all geodetic VLBI experiments from 1990-1993 and a series of 12 state-of-the-art R&D experiments run on consecutive days in January 1994. In both cases, when the gradient parameters are estimated, the overall fit of the geodetic solution is improved at greater than the 99% confidence level. Repeatabilities of baseline lengths ranging up to 11,000 km are improved by 1 to 8 mm in a root-sum-square sense. This varies from about 20% to 40% of the total baseline length scatter without gradient modeling for the 1990-1993 series and 40% to 50% for the January series. Gradients estimated independently for each day as a piecewise linear function are mostly continuous from day to day within their formal uncertainties. RP MACMILLAN, DS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NVI INC,CODE 9269,GREENBELT,MD 20771, USA. NR 10 TC 83 Z9 89 U1 1 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 MAY 1 PY 1995 VL 22 IS 9 BP 1041 EP 1044 DI 10.1029/95GL00887 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300010 ER PT J AU MISHCHENKO, MI LACIS, AA CARLSON, BE TRAVIS, LD AF MISHCHENKO, MI LACIS, AA CARLSON, BE TRAVIS, LD TI NONSPHERICITY OF DUST-LIKE TROPOSPHERIC AEROSOLS - IMPLICATIONS FOR AEROSOL REMOTE-SENSING AND CLIMATE MODELING SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIGHT-SCATTERING; PARTICLES; MATRICES AB The nonsphericity of dust-like tropospheric aerosols causes us to question the applicability of using conventional Mie theory to compute their radiative properties. In this paper we compare T-matrix computations of light scattering by polydispersions of randomly oriented nonspherical aerosols and Mie computations for equivalent spheres. We demonstrate that even moderate nonsphericity results in substantial errors in the retrieved aerosol optical thickness if satellite reflectance measurements are analyzed using Mie theory. On the other hand, the use of Mie theory for nonspherical aerosols produces negligible errors in the computation of albedo and flux related quantities, provided that the aerosol size distribution and optical thickness are known beforehand. The first result can be explained by large nonspherical-spherical differences in scattering phase function, while the second result follows from small nonspherical-spherical differences in single-scattering albedo and asymmetry parameter. Our results demonstrate that no cancellation of errors occurs if one consistently uses Mie theory in the retrieval algorithm and then in computing the albedo for the retrieved aerosol optical thickness. RP NASA, GODDARD INST SPACE STUDIES, SSAI, 2880 BROADWAY, NEW YORK, NY 10025 USA. RI Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; Mishchenko, Michael/D-4426-2012 NR 21 TC 163 Z9 167 U1 2 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1995 VL 22 IS 9 BP 1077 EP 1080 DI 10.1029/95GL00798 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300019 ER PT J AU PICKERING, KE THOMPSON, AM TAO, WK ROOD, RB MCNAMARA, DP MOLOD, AM AF PICKERING, KE THOMPSON, AM TAO, WK ROOD, RB MCNAMARA, DP MOLOD, AM TI VERTICAL TRANSPORT BY CONVECTIVE CLOUDS - COMPARISONS OF 3 MODELING APPROACHES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID 10-11 JUNE 1985; SYSTEM AB We have performed a preliminary comparison of the GEOS-1 (Goddard Earth Observing System) data assimilation system convective cloud mass fluxes with fluxes from a cloud-resolving model (the Goddard Cumulus Ensemble Model, GCE). A squall line case study (10-11 June 1985 Oklahoma PRESTORM episode) is the basis comparison. Regional (central U. S.) convective mass flux for June 1985 from GEOS-1 compares favorably with estimates from a statistical/dynamical approach using GCE simulations and satellite-derived cloud observations. The GEOS-1 convective mass fluxes produce reasonable estimates of monthly-averaged regional convective venting of CO from the boundary layer at least in an urban-influenced continental region, suggesting that they can be used in tracer transport simulations. C1 NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771. APPL RES CORP,LANDOVER,MD 20785. GEN SCI CORP,LAUREL,MD. RP PICKERING, KE (reprint author), UNIV MARYLAND,JOINT CTR EARTH SYST SCI,DEPT METEOROL,COLLEGE PK,MD 20742, USA. RI Pickering, Kenneth/E-6274-2012; Rood, Richard/C-5611-2008; Thompson, Anne /C-3649-2014 OI Rood, Richard/0000-0002-2310-4262; Thompson, Anne /0000-0002-7829-0920 NR 10 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1995 VL 22 IS 9 BP 1089 EP 1092 DI 10.1029/95GL00889 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300022 ER PT J AU MOTE, PW ROSENLOF, KH HOLTON, JR HARWOOD, RS WATERS, JW AF MOTE, PW ROSENLOF, KH HOLTON, JR HARWOOD, RS WATERS, JW TI SEASONAL-VARIATIONS OF WATER-VAPOR IN THE TROPICAL LOWER STRATOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Measurements of stratospheric water vapor by the Microwave Limb Sounder aboard the Upper Atmosphere Research Satellite show that in the tropical lower stratosphere, low-frequency variations are closely related to the annual cycle in tropical tropopause temperatures. Tropical stratospheric air appears to retain information about the tropopause conditions it encountered for over a year as it rises through the stratosphere. We use a two-dimensional Lagrangian model to relate MLS measurements to the temperature that tropical air parcels encountered when crossing the 100 hPa surface. C1 UNIV WASHINGTON,DEPT ATMOSPHER SCI AK40,SEATTLE,WA 98195. UNIV COLORADO,NOAA,ERL,COOPERAT INST RES ENVIRONM SCI,BOULDER,CO 80303. CALTECH,JET PROP LAB,PASADENA,CA 91109. UK UNIV GLOBAL ATMOSPHER MODELLING PROGRAMME,READING,BERKS,ENGLAND. RP MOTE, PW (reprint author), UNIV EDINBURGH,DEPT METEOROL,JCMB,KINGS BLDG,EDINBURGH EH9 3JZ,MIDLOTHIAN,SCOTLAND. RI Rosenlof, Karen/B-5652-2008 OI Rosenlof, Karen/0000-0002-0903-8270 NR 15 TC 80 Z9 80 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1995 VL 22 IS 9 BP 1093 EP 1096 DI 10.1029/95GL01234 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300023 ER PT J AU OSBORN, MT DECOURSEY, RJ TREPTE, CR WINKER, DM WOODS, DC AF OSBORN, MT DECOURSEY, RJ TREPTE, CR WINKER, DM WOODS, DC TI EVOLUTION OF THE PINATUBO VOLCANIC CLOUD OVER HAMPTON, VIRGINIA SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LIDAR; AEROSOL AB A ground-based lidar system at NASA Langley Research Center in Hampton; Virginia, has monitored the stratospheric aerosol vertical distribution and loading since 1974. The eruption of Mt. Pinatubo in June 1991 produced the largest enhancement of stratospheric aerosol loading ever observed by lidar over this mid-latitude location. Low altitude layers (<20 km) were the first to arrive over Hampton in early August, the result of transport associated with a tropospheric anticyclonic cell over North America. The maximum peak scattering ratio, 34 at 22.4 km, and the maximum stratospheric integrated backscatter of 0.0053 sr(-1), both at 694 nm, observed since the eruption were measured on February 20, 1992. After decreasing during the spring and summer of 1992, the aerosol burden increased significantly during the winter of 1992-3, evidence of poleward winter transport from the equatorial reservoir. Over the period from February 1992 to February 1994, the stratospheric aerosol loading decreased with an average 1/e decay time of 10.1 months. The vertical distribution, intensity, and transport of Pinatubo aerosols over Hampton, Virginia, are described in detail and compared with similar measurements after El Chichon. C1 NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681. RP OSBORN, MT (reprint author), SCI APPLICAT INT CORP,1 ENTERPRISE PKWY,HAMPTON,VA 23666, USA. NR 12 TC 38 Z9 38 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1995 VL 22 IS 9 BP 1101 EP 1104 DI 10.1029/95GL00815 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300025 ER PT J AU RINSLAND, CP GUNSON, MR KO, MKW WEISENSTEIN, DW ZANDER, R ABRAMS, MC GOLDMAN, A SZE, ND YUE, GK AF RINSLAND, CP GUNSON, MR KO, MKW WEISENSTEIN, DW ZANDER, R ABRAMS, MC GOLDMAN, A SZE, ND YUE, GK TI H2SO4 PHOTOLYSIS - A SOURCE OF SULFUR-DIOXIDE IN THE UPPER-STRATOSPHERE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MOUNT-PINATUBO ERUPTION; SO2; VOLCANO; IMPACT; PLUME; LIDAR; VAPOR AB Numerous absorption lines of stratospheric sulfur dioxide (SO2) have been identified in solar occultation spectra recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS)-1 shuttle mission (March 24-April 2, 1992). Based on their analysis, a volume mixing ratio profile of SO2 increasing from (13 +/-4) p.p.t.v. (parts per 10(-12) by volume) at 16 mbar (similar to 28 km) to 455 +/-90 p.p.t.v, at 0.63 mbar (similar to 52 km) has been measured with no significant profile differences between 20 degrees N and 60 degrees S latitude. The increase in the SO;! mixing ratios with altitude indicates the presence of a source of SO2 in the upper stratosphere. Profiles retrieved from ATMOS spectra recorded during shuttle flights in April-May 1985 and April 1993 show similar vertical distributions but lower concentrations. Two-dimensional model calculations with SO2 assumed as the end product of H2SO4 photolysis produce SO2 profiles consistent with the ATMOS measurements to within about a factor of 2. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. ATMOSPHER & ENVIRONM RES INC,CAMBRIDGE,MA 02139. UNIV LIEGE,INST ASTROPHYS,B-4000 LIEGE,BELGIUM. UNIV DENVER,DEPT PHYS,DENVER,CO 80208. RP RINSLAND, CP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,MAIL STOP 401A,HAMPTON,VA 23681, USA. RI Ko, Malcolm/D-5898-2015 NR 27 TC 40 Z9 40 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 MAY 1 PY 1995 VL 22 IS 9 BP 1109 EP 1112 DI 10.1029/95GL00917 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300027 ER PT J AU NAKAMURA, R BAKER, DN BLAKE, JB KANEKAL, S KLECKER, B HOVESTADT, D AF NAKAMURA, R BAKER, DN BLAKE, JB KANEKAL, S KLECKER, B HOVESTADT, D TI RELATIVISTIC ELECTRON-PRECIPITATION ENHANCEMENTS NEAR THE OUTER EDGE OF THE RADIATION BELT SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR; ORBIT AB We examined characteristics of relativistic electron precipitation bursts observed by the Heavy Ion Large Telescope (HILT) experiment onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite. We report on relatively narrow, persistent, latitudinal bands of precipitation with time scales of 10 similar to 30 sec near the outer edge of the radiation belt: these develop and decay with a time scale of a few hours. Acceleration processes more effective than the usual radial diffusion process or scattering process would be needed to explain this strong precipitation band phenomenon. Another prominent signature is microbursts with a time scale down to a few hundred milliseconds. It is suggest that these microbursts are due to wave-particle interaction involving a relaxation-oscillator type of mechanism. C1 UNIV COLORADO,LASP,BOULDER,CO 80309. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. MAX PLANCK INST EXTRATERR PHYS,D-85740 GARCHING,GERMANY. AEROSP CORP,SPACE SCI LAB,LOS ANGELES,CA 90009. RP NAKAMURA, R (reprint author), NAGOYA UNIV,STEL,TOYOKAWA,AICHI 442,JAPAN. RI Nakamura, Rumi/I-7712-2013 OI Nakamura, Rumi/0000-0002-2620-9211 NR 18 TC 32 Z9 32 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 MAY 1 PY 1995 VL 22 IS 9 BP 1129 EP 1132 DI 10.1029/95GL00378 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300032 ER PT J AU KARMESIN, SR LIEWER, PC BRACKBILL, JU AF KARMESIN, SR LIEWER, PC BRACKBILL, JU TI MOTION OF THE TERMINATION SHOCK IN RESPONSE TO AN 11-YEAR VARIATION IN THE SOLAR-WIND SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DISTANCE AB A two-dimensional hydrodynamic numerical model has been used to study the motion of the termination shock in response to an 11 year variation in the solar wind ram pressure. We find that for a total variation in the ram pressure by a factor of 2, a termination shock at 89 AU moves inward and outward about +/-8% of its distance with a typical velocity of 12 km/sec. This movement may be understood in terms of the various time scales associated with the response of the termination shock and heliopause to variations in the solar wind ram pressure. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RP CALTECH, DEPT APPL MATH, PASADENA, CA 91125 USA. NR 12 TC 65 Z9 65 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1995 VL 22 IS 9 BP 1153 EP 1156 DI 10.1029/95GL00603 PG 4 WC Geosciences, Multidisciplinary SC Geology GA QW543 UT WOS:A1995QW54300038 ER PT J AU CHAUVINEAU, B FARINELLA, P HARRIS, AW AF CHAUVINEAU, B FARINELLA, P HARRIS, AW TI THE EVOLUTION OF EARTH-APPROACHING BINARY ASTEROIDS - A MONTE-CARLO DYNAMICAL MODEL SO ICARUS LA English DT Article ID GRAVITATIONAL ENCOUNTERS; RADAR IMAGES; SATELLITES AB We have developed a Monte Carlo model of the dynamical evolution of a binary asteroid crossing the Earth's orbit. At each close encounter with the Earth, the binary system undergoes impulsive variations of its orbital energy and angular momentum. Thus, after a great number of encounters, the system is dynamically evolved, and the two components may have either collided or escaped ''to infinity.'' Tidal interactions between any two successive encounters also contribute to this dynamical evolution and change the original rotation rates of the components. We have carried out simulations of the evolution process under a variety of initial conditions and confirm that in general the characteristic evolution time is shorter than the typical lifetime of Earth-crossing asteroids vs collisions with the inner planets (approximate to 100 Myr). The radar images obtained recently for several Earth-crossers reveal ''bifurcated'' structures which have been interpreted as contact binaries resulting from low-velocity collisions between two formerly separated components. In our scenario, such structures can be understood as resulting from dynamically evolved binary asteroids-although in the case of (4179) Toutatis the current rotation is so slow that it would require an unlikely cancellation of rotational and orbital angular momentum at the impact between the components. On the other hand, some other near-Earth objects with long rotation periods may be explained by tidal despinning within binary systems, followed by escape of the components. Moreover, collisions with the Earth of relatively young, well-separated binaries may explain the existence of doublet craters. (C) 1995 Academic Press, Inc. C1 UNIV PISA,DIPARTIMENTO MATEMAT,MECCAN SPAZIALE GRP,I-56127 PISA,ITALY. OBSERV COTE AZUR,DEPT CASSINI,F-06304 NICE 4,FRANCE. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP CHAUVINEAU, B (reprint author), OBSERV COTE AZUR,DEPT CERGA,AVE COPERN,F-06130 GRASSE,FRANCE. NR 23 TC 22 Z9 22 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 1995 VL 115 IS 1 BP 36 EP 46 DI 10.1006/icar.1995.1076 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA177 UT WOS:A1995RA17700002 ER PT J AU VILAS, F AF VILAS, F TI IS THE U-B COLOR SUFFICIENT FOR IDENTIFYING WATER OF HYDRATION ON SOLAR-SYSTEM BODIES SO ICARUS LA English DT Note ID ASTEROIDS AB The U-B color has been suggested as a predictor of the presence of water of hydration on asteroids, Photometry from the Eight-Color Asteroid Survey Was used to test this concept, An overlap in U-B colors prevents this magnitude difference from distinguishing between surface material that was thermally processed at higher temperatures and surface material that was aqueously altered. Two tests of the presence of water of hydration using visible spectral region photometry failed to flag those few higher albedo M- and E-class asteroids having photometry that shows a 3.0-mu m water of hydration absorption, These asteroids probably contain little or no oxidized iron in their surface material. (C) 1995 Academic Press, Inc. RP VILAS, F (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN3,HOUSTON,TX 77058, USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD MAY PY 1995 VL 115 IS 1 BP 217 EP 218 DI 10.1006/icar.1995.1092 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA RA177 UT WOS:A1995RA17700018 ER PT J AU NELSON, ML BIANCO, DJ AF NELSON, ML BIANCO, DJ TI ACCESSING NASA TECHNOLOGY WITH THE WORLD-WIDE-WEB SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB NASA Langley Research Center (LaRC) began using the World Wide Web (WWW) in the summer of 1993, becoming the first NASA installation to provide a center-wide home page. This coincided with;a reorganization of LaRC to provide a more concentrated focus on technology transfer to both aerospace and non-aerospace industry. Use of WWW and NCSA Mosaic not only provides automated information dissemination, but also allows for the implementation, evolution and integration of many technology transfer and. technology awareness applications. This paper describes several of these innovative applications,,including the on-line presentation of the entire Technology OPportunities Showcase (TOPS), an industrial partnering showcase that exists on the Web long after the actual 3-day event ended. The NASA Technical Report Server (NTRS) provides uniform access to many logically similar, yet physically distributed NASA report servers. WWW is also the foundation of the Langley Software Server (LSS), an experimental software distribution system which will distribute LaRC-developed software. In addition to the more formal technology distribution projects, WWW has been successful in connecting people with technologies and people with other people. C1 NASA,LANGLEY RES CTR,COMP SCI CORP,HAMPTON,VA. RP NELSON, ML (reprint author), NASA,LANGLEY RES CTR,DIV INFORMAT SYST,HAMPTON,VA 23665, USA. OI Nelson, Michael/0000-0003-3749-8116 NR 10 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 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD MAY PY 1995 VL 10 IS 5 BP 7 EP 13 DI 10.1109/62.373992 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA QW395 UT WOS:A1995QW39500004 ER PT J AU BARNES, NP THOMAS, ME KOCH, GJ MARSH, WD AF BARNES, NP THOMAS, ME KOCH, GJ MARSH, WD TI ATMOSPHERIC THERMAL LENSING IN LASER RESONATORS SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB Atmospheric absorption degrades laser performance both by absorbing laser energy within the laser resonator, which increases the loss, and by inducing a thermal lens in the atmosphere. Atmospheric thermal lensing can be quite severe, even when the absorption coefficient is quite modest, A model is developed which describes atmospheric thermal lensing; time constants, which are associated with the establishment and decay of the atmospheric thermal lens, are determined; experiments are performed using an injection seeded Ti:Al2O3 laser tuned to the H2O absorption lines near 0.815 mu m to validate the model; dependence of the atmospheric thermal lens on the laser energy and absorption coefficient were measured and found to agree with the model, In addition, the decay of the atmospheric thermal lens with time was measured and also found to agree with the model predictions. C1 SCI & TECHNOL CORP,HAMPTON,VA 23666. SCI APPLICAT INT CORP,HAMPTON,VA 23666. RP BARNES, NP (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 14 TC 2 Z9 2 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAY PY 1995 VL 31 IS 5 BP 962 EP 969 DI 10.1109/3.375943 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA QT614 UT WOS:A1995QT61400023 ER PT J AU MORRIS, NA CONNOLLY, JC MARTINELLI, RU ABELES, JH COOK, AL AF MORRIS, NA CONNOLLY, JC MARTINELLI, RU ABELES, JH COOK, AL TI SINGLE-MODE DISTRIBUTED-FEEDBACK 761-NM GAAS-ALGAAS QUANTUM-WELL LASER SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article AB We have developed single-mode distributed-feedback 761-nm GaAs-AlGaAs quantum well lasers as sources for O-2 sensing through laser absorption spectroscopy, Devices containing a 4-mu m-wide ridge waveguide exhibit low threshold currents of 25 mA and quantum efficiencies greater than 35% at output powers in excess of 25 mW. The spectral linewidths of these devices are 12.0 MHz at 15 mW. Temperature- and current-tuning rates are 0.06 nm/degrees C and 0.0075 nm/mA (-3.9 GHz/mA), respectively, The devices display smooth, continuous, single-mode wavelength tuning over a 4.2 nm interval. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP MORRIS, NA (reprint author), DAVID SARNOFF RES CTR,PRINCETON,NJ 08543, USA. NR 7 TC 21 Z9 21 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 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAY PY 1995 VL 7 IS 5 BP 455 EP 457 DI 10.1109/68.384508 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA QX704 UT WOS:A1995QX70400006 ER PT J AU KELKAR, AG JOSHI, SM ALBERTS, TE AF KELKAR, AG JOSHI, SM ALBERTS, TE TI PASSIVITY-BASED CONTROL OF NONLINEAR FLEXIBLE MULTIBODY SYSTEMS SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Note AB In this paper, global asymptotic stability of a class of nonlinear multibody flexible space structures under certain dissipative compensation is established. Furthermore, for an important subclass of such systems, the stability is shown to be robust to certain types of actuator and sensor nonlinearities. The results are applicable to robust stabilization of a wide class of systems, including flexible space structures and manipulators with articulated flexible appendages. The stability proofs use the Lyapunov approach and exploit the inherent passivity of such systems. C1 OLD DOMINION UNIV,NORFOLK,VA 23529. RP KELKAR, AG (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 18 TC 17 Z9 20 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD MAY PY 1995 VL 40 IS 5 BP 910 EP 914 DI 10.1109/9.384228 PG 5 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA QW390 UT WOS:A1995QW39000014 ER PT J AU RICHIE, JE GANGL, HR AF RICHIE, JE GANGL, HR TI EFIE-MFIE HYBRID SIMULATION USING NEC-VSWR FOR THE WISP EXPERIMENT SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Note AB The use of the numerical electromagnetics code for modeling wires and wire grids (EFIE) has been reviewed recently. This work is an extension of the work of C. A. Balanis that utilizes a patch model, and computes input impedance (as VSWR) using NEC. The work presented here is a simulation and measurement study for the proposed NASA waves in space plasma (WISP) experiment. Some modeling guidelines for patch models are discussed. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,INFORMAT & ELECTR SYST LAB,HUNTSVILLE,AL 35812. RP RICHIE, JE (reprint author), MARQUETTE UNIV,DEPT ELECT & COMP ENGN,1515 W WISCONSIN AVE,MILWAUKEE,WI 53233, USA. NR 11 TC 3 Z9 9 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 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD MAY PY 1995 VL 37 IS 2 BP 293 EP 296 DI 10.1109/15.385897 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA QY830 UT WOS:A1995QY83000020 ER PT J AU LEMOIGNE, J TILTON, JC AF LEMOIGNE, J TILTON, JC TI REFINING IMAGE SEGMENTATION BY INTEGRATION OF EDGE AND REGION DATA SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article AB A basic requirement for understanding the dynamics of the Earth's major ecosystems is accurate quantitative information about the distribution and areal extent of the Earth's vegetation formations, Some of this required information can be obtained through the analysis of remotely sensed data, Image segmentation is often one of the first steps of this analysis, This paper focuses on two particular types of segmentation: region-based and edge-based segmentations, Each approach is affected differently by various factors, and both types of segmentations may be improved by taking advantage of their complementary nature, Included among region-based segmentation approaches are region growing methods, which produce hierarchical segmentations of images from finer to coarser resolution. In this hierarchy, an ideal segmentation (ideal for a given application) does not always correspond to one single iteration, but may correspond to several different iterations, This, among other factors, makes it somewhat difficult to choose a stopping criterion for region growing methods, To find the ideal segmentation, we develop a stopping criterion for our Iterative Parallel Region Growing (IPRG) algorithm using additional information from edge features, and the Hausdorff distance metric, We integrate information from regions and edges at the symbol level, taking advantage of the hierarchical structure of the region segmentation results, Also, to demonstrate the feasibility of this approach in processing the massive amount of data that will be generated by future Earth remote sensing missions, such as the Earth Observing System (EOS), all the different steps of this algorithm (namely, region growing, edge detection, Hausdorff distance computation, and edge/region fusion) have been implemented on a massively parallel processor. C1 NASA, GODDARD SPACE FLIGHT CTR, DIV SPACE DATA & COMP, INFORMAT SCI & TECHNOL BRANCH, GREENBELT, MD 20771 USA. RP LEMOIGNE, J (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CTR EXCELLENCE SPACE DATA & INFORMAT SCI, COMPUTAT SCI BRANCH, GREENBELT, MD 20771 USA. NR 23 TC 50 Z9 50 U1 4 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1995 VL 33 IS 3 BP 605 EP 615 DI 10.1109/36.387576 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 RB114 UT WOS:A1995RB11400009 ER PT J AU ABRAMS, M HOOK, SJ AF ABRAMS, M HOOK, SJ TI SIMULATED ASTER DATA FOR GEOLOGIC STUDIES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID CUPRITE; NEVADA; IMAGES AB The Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) is a high spatial resolution imaging instrument, scheduled to be launched on NASA's Earth Observing System AM-1 satellite platform in 1998, ASTER acquires data in 14 bands, spanning the visible, near-infrared, short-wavelength infrared, and thermal infrared spectral regions, with spatial resolution varying from 15-90 m, depending on wavelength, In order to evaluate our ability to use ASTER data for geological mapping, we created a simulated 14-band ASTER data set for Cuprite, Nevada, The study site has sparse vegetation and exposes a wide range of unaltered and hydrothermally altered volcanic rocks, The wide range of wavelengths covered by ASTER allowed us to distinguish iron oxide minerals, clay-bearing minerals, sulfate minerals, ammonia minerals, siliceous rocks, and carbonates. Based on interpretation of the ASTER data, and in conjunction with laboratory and field spectral measurements, we produced an alteration map showing the distribution of argillized rocks, opalized rocks with alunite, silicified rocks, and areas dominated by kaolinite and buddingtonite. The map was as accurate as published maps made by traditional field methods, ASTER should be an improvement over existing satellite systems for geologic mapping. RP ABRAMS, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 28 TC 56 Z9 61 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 MAY PY 1995 VL 33 IS 3 BP 692 EP 699 DI 10.1109/36.387584 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 RB114 UT WOS:A1995RB11400017 ER PT J AU NGHIEM, SV LI, FK LOU, SH NEUMANN, G MCINTOSH, RE CARSON, SC CARSWELL, JR WALSH, EJ DONELAN, MA DRENNAN, WM AF NGHIEM, SV LI, FK LOU, SH NEUMANN, G MCINTOSH, RE CARSON, SC CARSWELL, JR WALSH, EJ DONELAN, MA DRENNAN, WM TI OBSERVATIONS OF RADAR BACKSCATTER AT KU AND C-BANDS IN THE PRESENCE OF LARGE WAVES DURING THE SURFACE-WAVE DYNAMICS EXPERIMENT SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID A SATELLITE SCATTEROMETER; CROSS-SECTIONS; X-BAND; WIND-SPEED; OCEAN; SEA; DEPENDENCE; SCATTERING; BREAKING; MODEL AB Ocean radar backscatter in the presence of large waves is investigated using data acquired with the Jet Propulsion Laboratory NUSCAT radar at Ku band for horizontal and vertical polarizations and the University of Massachusetts CSCAT radar at C band for vertical polarization during the Surface Wave Dynamics Experiment, off-nadir backscatter data of ocean surfaces were obtained in the presence of large waves with significant wave height up to 5.6 m. In moderate-wind cases, effects of large waves are not detectable within the measurement uncertainty and no noticeable correlation between backscatter coefficients and wave height is found. Under high-wave light-wind conditions, backscatter is enhanced significantly at large incidence angles with a weaker effect at small incidence angles. Backscatter coefficients in the wind speed range under consideration are compared with SASS-II (Ku band), CMOD3-H1 (C band), and Plant's model results which confirm the experimental observations, Variations of the friction velocity, which can give rise to the observed backscatter behaviors in the presence of large waves, are presented. C1 UNIV MASSACHUSETTS,DEPT ELECT ENGN,AMHERST,MA 01003. NASA,GODDARD SPACE FLIGHT CTR,OBSERVAT SCI BRANCH,HYDROSPHER PROC LAB,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA. NATL WATER RES INST BRANCH,BURLINGTON,ON,CANADA. RP NGHIEM, SV (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 24 TC 28 Z9 28 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1995 VL 33 IS 3 BP 708 EP 721 DI 10.1109/36.387586 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RB114 UT WOS:A1995RB11400019 ER PT J AU HARA, Y ATKINS, RG SHIN, RT KONG, JA YUEH, SH KWOK, R AF HARA, Y ATKINS, RG SHIN, RT KONG, JA YUEH, SH KWOK, R TI APPLICATION OF NEURAL NETWORKS FOR SEA-ICE CLASSIFICATION IN POLARIMETRIC SAR IMAGES SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID REMOTE-SENSING DATA AB Classification of sea ice types using polarimetric radar is an area of considerable current interest and research. Several automatic methods have been developed to classify sea ice types from fully polarimetric synthetic aperture radar (SAR) images, and these techniques are generally grouped into supervised and unsupervised approaches. In previous work, supervised methods have been shown to yield higher accuracy than unsupervised techniques, but suffer from the need for human interaction to determine classes and training regions. In contrast, unsupervised methods determine classes automatically, but generally show limited ability to accurately divide terrain into natural classes. In this paper, a new classification technique is applied to determine sea ice types in polarimetric and multifrequeucy SAR images, utilizing an unsupervised neural network to provide automatic classification, and employing an iterative algorithm to improve the performance. The Learning Vector Quantization (LVQ) is first applied to the unsupervised classification of SAR images, and the results are compared with those of a conventional technique, the Migrating Means method. Results show that LVQ outperforms the Migrating Means method, but performance is still poor. An iterative algorithm is then applied where the SAR image is reclassified using the Maximum Likelihood (ML) classifier. It is shown that this algorithm converges, and significantly improves classification accuracy. The new algorithm successfully identifies first-year and multiyear sea ice regions in the images at three frequencies. The results show that L- and P-band images have similar characteristics, while the C-band image Is substantially different. Classification based on single features is also carried out using LVQ and the iterative ML method. It is found that the fully polarimetric classification provides a higher accuracy than those based on a single feature. The significance of multilook classification is demonstrated by comparing the results obtained using four-look and single-look classifications. The results show the effect of multilook classification on reducing the speckle in the classified image. C1 MIT,DEPT ELECT ENGN & COMP SCI,CAMBRIDGE,MA 01239. MIT,ELECTR RES LAB,CAMBRIDGE,MA 01239. CALTECH,JET PROPULS LAB,PASADENA,CA 91109. RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 18 TC 20 Z9 22 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1995 VL 33 IS 3 BP 740 EP 748 DI 10.1109/36.387589 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RB114 UT WOS:A1995RB11400022 ER PT J AU HLAVKA, CA SPANNER, MA AF HLAVKA, CA SPANNER, MA TI UNMIXING AVHRR IMAGERY TO ASSESS CLEARCUTS AND FOREST REGROWTH IN OREGON SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article ID LOSSES AB Advanced Very High Resolution Radiometer imagery provides frequent and low-cost coverage of the earth, but its coarse spatial resolution (1.1 km by 1.1 km) does not lend itself to standard techniques of automated categorization of land cover classes because the pixels are generally mixed; that is, the extent of the pixel includes several land use/cover classes, Unmixing procedures were developed to extract land use/cover class signatures from mixed pixels, using Landsat Thematic Mapper data as a source for the training set, and to estimate fractions of class coverage within pixels, Application of these unmixing procedures to mapping forest clearcuts and regrowth in Oregon indicated that unmixing is a promising approach for mapping major trends in land cover with AVHRR bands 1 and 2. Including thermal bands by unmixing AVHRR bands 1-4 did not lead to significant improvements in accuracy, but experiments with unmixing these four bands did indicate that use of weighted least squares techniques might lead to improvements in other applications of unmixing. RP HLAVKA, CA (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV INC,DIV EARTH SYST SCI,MOFFETT FIELD,CA 94035, USA. NR 21 TC 33 Z9 34 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 1995 VL 33 IS 3 BP 788 EP 795 DI 10.1109/36.387594 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 RB114 UT WOS:A1995RB11400027 ER PT J AU DURDEN, SL MORRISSEY, LA LIVINGSTON, GP AF DURDEN, SL MORRISSEY, LA LIVINGSTON, GP TI MICROWAVE BACKSCATTER AND ATTENUATION DEPENDENCE ON LEAF-AREA INDEX FOR FLOODED RICE FIELDS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Note ID FOREST; VEGETATION AB Wetlands are important for their role in global climate as a source of methane and other reduced trace gases. As part of an effort to determine whether radar is suitable for wetland vegetation monitoring, we have studied the dependence of microwave backscatter and attenuation on leaf area index (LAI) for flooded rice fields. We find that the radar return from a flooded rice field does show dependence on LAI. In particular, the C-band VV cross section per unit area decreases with increasing LAI. A simple model for scattering from rice fields is derived and fit to the observed HH and VV data. The model fit provides insight into the relation of backscatter to LAI and is also used to calculate the canopy path attenuation as a function of LAI. C1 NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV,MOFFETT FIELD,CA 94035. RP DURDEN, SL (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91190, USA. NR 15 TC 22 Z9 24 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 MAY PY 1995 VL 33 IS 3 BP 807 EP 810 DI 10.1109/36.387599 PG 4 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA RB114 UT WOS:A1995RB11400031 ER PT J AU WELLER, TM KATEHI, LPB MCGRATH, WR AF WELLER, TM KATEHI, LPB MCGRATH, WR TI ANALYSIS AND DESIGN OF A NOVEL NONCONTACTING WAVE-GUIDE BACKSHORT SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article ID DISCONTINUITIES AB A new noncontacting waveguide backshort has recently been developed for millimeter- and submillimeter-wave frequencies, The design consists of a metal bar with rectangular holes cut into it, which is covered with a dielectric layer to form a snug fit with the broadwalls of a waveguide. It is mechanically rugged and can be readily fabricated for frequencies from 1-1000 GHz, This paper presents a technique for the theoretical characterization of the backshort, using an approach that combines the mode-matching method and a set of coupled space-domain integral equations. The convergence characteristics of the analysis are included, along with a set of general design guidelines. C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. RP WELLER, TM (reprint author), UNIV MICHIGAN,DEPT ELECT ENGN & COMP SCI,RADIAT LAB,ANN ARBOR,MI 48109, USA. NR 15 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 1995 VL 43 IS 5 BP 1023 EP 1030 DI 10.1109/22.382061 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA QW252 UT WOS:A1995QW25200005 ER PT J AU CHINN, GC EPP, LW WILKINS, GM AF CHINN, GC EPP, LW WILKINS, GM TI DETERMINATION OF THE EIGENFREQUENCIES OF A FERRITE-FILLED CYLINDRICAL CAVITY RESONATOR USING THE FINITE-ELEMENT METHOD SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Note AB A formulation of the Finite Element Method (FEM) particular to axisymmetric problems containing anisotropic media is compared to an analytic solution. In particular, the resonant frequencies of a longitudinally biased ferrite-filled cylindrical cavity are examined. For comparison, a solution of the characteristic equation for the lossless, ferrite-filled cylindrical waveguide was modified to give the resonant frequencies of the cylindrical cavity. This analytical solution was then used to examine the error in the FEM formulation for the anisotropic case. It is noted that the FEM formulation for anisotropic material presented, based on both node and edge-based elements, is found to be free of spurious solutions. C1 MORGAN STATE UNIV,BALTIMORE,MD 21239. RP CHINN, GC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 4 TC 8 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 1995 VL 43 IS 5 BP 1207 EP 1209 DI 10.1109/22.382089 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA QW252 UT WOS:A1995QW25200032 ER PT J AU GEDNEY, SD LANSING, F AF GEDNEY, SD LANSING, F TI A PARALLEL PLANAR GENERALIZED YEE ALGORITHM FOR THE ANALYSIS OF MICROWAVE CIRCUIT DEVICES SO INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS LA English DT Article AB The planar generalized Yee (PGY) algorithm is an extension of the generalized Yee algorithm and the discrete surface integral (DSI) methods, which are based on explicit time-marching solutions of Maxwell's equations. Specifically, the PGY algorithm exploits the planar symmetries of printed microwave circuit devices, achieving great savings in both CPU time and memory. Since the PGY algorithm is an explicit method, it has a high degree of parallelism. To this end, a highly scalable parallel algorithm based on a spatial decomposition of the general unstructured mesh is presented. Two spatial decompositions are compared, the recursive inertia partitioning (RIP) algorithm and the Greedy algorithm. The Greedy algorithm provides optimal load balance, whereas the RIP algorithm more effectively minimizes shared boundary interface lengths. Through numerical examples, it is demonstrated that the Greedy algorithm provides superior speedups. It is also demonstrated that the parallel PGY algorithm is a highly scalable algorithm. C1 CALTECH,JET PROP LAB,SPACE TELECOMMUN EQUIPMENT SECT,PASADENA,CA 91109. RP GEDNEY, SD (reprint author), UNIV KENTUCKY,DEPT ELECT ENGN,LEXINGTON,KY 40506, USA. RI Gedney, Stephen/I-5590-2012 NR 12 TC 5 Z9 5 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0894-3370 J9 INT J NUMER MODEL EL JI Int. J. Numer. Model.-Electron. Netw. Device Fields PD MAY-AUG PY 1995 VL 8 IS 3-4 BP 249 EP 263 DI 10.1002/jnm.1660080310 PG 15 WC Engineering, Electrical & Electronic; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA RJ832 UT WOS:A1995RJ83200009 ER PT J AU EKATERINARIS, JA COUTLEY, RL SCHIFF, LB PLATZER, MF AF EKATERINARIS, JA COUTLEY, RL SCHIFF, LB PLATZER, MF TI NUMERICAL INVESTIGATION OF HIGH-INCIDENCE FLOW OVER A DOUBLE-DELTA WING SO JOURNAL OF AIRCRAFT LA English DT Article AB The vortical flowfield over a double-delta wing configuration, consisting of a sharp leading-edge 76-deg sweep strake and a 40-deg sweep wing section is investigated numerically. The governing equations are solved with a partially upwind, finite difference, two-factor algorithm. The leeward-side vortex system resulting from the strake and wing vortices is investigated for a subsonic freestream speed of M(infinity) = 0.22, high Reynolds number turbulent flow at various angles of incidence. At low angles of attack the strake and wing vortices remain separate over the wing section, whereas for flows at higher angles of attack the two vortices merge and vortex breakdown develops. Vortex breakdown appears initially in the trailing-edge region of the wing section. As the angle of attack increases, bursting occurs further upstream closer to the strake section. The effect of numerical grid density is investigated, and the solutions are compared with available experimental data. The computed surface pressures are in good agreement with the experimental measurements for the lower angles of attack, but the agreement deteriorates as the angle of attack increases. RP EKATERINARIS, JA (reprint author), USN,POSTGRAD SCH,NASA,JOINT INST AERONAUT,MONTEREY,CA 93943, USA. NR 0 TC 15 Z9 15 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 457 EP 463 DI 10.2514/3.46742 PG 7 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600001 ER PT J AU LAMAR, JE BRANDON, J JOHNSON, TD AF LAMAR, JE BRANDON, J JOHNSON, TD TI QUANTIFIABLE VORTEX FEATURES OF F-106B AIRCRAFT AT SUBSONIC SPEEDS SO JOURNAL OF AIRCRAFT LA English DT Article AB Quantifiable vortex features and separated-flow origins have been determined on an F-106B aircraft at 1-g subsonic speeds using the vapor-screen technique coupled with image enhancement, photogrammetry, and computer graphics, In particular, the spatial location of vortex cores, their tracks over the wing, and the approximate reattachment locations have been determined as a function of angle of attack and Reynolds number, Increasing the Reynolds number generally delays or suppresses large-scale separation and promotes the formation of multiple vortices, whereas increasing the angle of attack generally promotes the formation of a single vortex system. The multiple vortices observed may likely be attributed to small surface distortions in the wing leading-edge region. Comparisons of off-surface determined vortex core location and reattachment point approximation from the vapor-screen technique are made with those from the on-surface techniques of static pressure and oil now and show generally good agreement. A comparison between quantified vortex features from flight and wind tunnel showed reasonably good agreement over the forward part of the wing for angles of attack from 16 to 20 deg. RP LAMAR, JE (reprint author), NASA,LANGLEY RES CTR,VEHICLE PERFORMANCE BRANCH,M-S 247,HAMPTON,VA 23681, 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 MAY-JUN PY 1995 VL 32 IS 3 BP 464 EP 470 DI 10.2514/3.46743 PG 7 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600002 ER PT J AU RUMSEY, CL VATSA, VN AF RUMSEY, CL VATSA, VN TI COMPARISON OF THE PREDICTIVE CAPABILITIES OF SEVERAL TURBULENCE MODELS SO JOURNAL OF AIRCRAFT LA English DT Article AB Four turbulence models are evaluated for transonic separated flows using two well-established solvers, one upwind and one central difference. The equilibrium model of Baldwin-Lomax predicts separated-now shock locations too far aft, The effects of several modifications to the half-equation model of Johnson-King are explored in detail, and different versions of the model are compared. Good results for two- and three-dimensional flows can be obtained using two different versions of this model. The one-equation models of Baldwin-Barth and Spalart-Allmaras perform well for airfoil flows, but can predict the shock too far forward at the outboard stations of a separated wing. The effects of numerical truncation error are assessed using grid-refinement studies in combination with varying the numerical dissipation levels in both codes. RP RUMSEY, CL (reprint author), NASA,LANGLEY RES CTR,DIV FLUID MECH,M-S 128,HAMPTON,VA 23681, USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 510 EP 514 DI 10.2514/3.46749 PG 5 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600008 ER PT J AU YIP, LP VIJGEN, PMHW HARDIN, JD VANDAM, CP AF YIP, LP VIJGEN, PMHW HARDIN, JD VANDAM, CP TI IN-FLIGHT PRESSURE MEASUREMENTS ON A SUBSONIC TRANSPORT HIGH-LIFT WING SECTION SO JOURNAL OF AIRCRAFT LA English DT Article AB The NASA Langley Transport Systems Research Vehicle (B737-100 aircraft) was used to obtain in-flight flow characteristics including surface pressures and surface shear stresses for a full-chord wing section, including the slat, main-wing, and triple-slotted, Fowler-flap elements. Chordwise pressure distributions were obtained at the 58% semispan station using thin pressure belts. Flow characteristics observed in the chordwise pressure distributions included leading-edge regions of high-subsonic flows, leading-edge attachment-line locations, slat and main-wing cove-flow separation and reattachment, and trailing-edge flow separation. In addition, surface sheer-stress measurements were made using Preston-tube probes on each element. Computational analysis of the in-flight pressure measurements using two-dimensional, viscous-flow, multielement methods and simple-sweep theory showed reasonable agreement. However, overprediction of the suction pressures on the flap elements indicates a need for more detailed (off-surface) measurements of the flow and the in-flight flap geometry to aid modeling of the complex three-dimensional flowfield. RP YIP, LP (reprint author), NASA,LANGLEY RES CTR,DIV FLIGHT DYNAM & CONTROL,VEHICLE PERFORMANCE BRANCH,HAMPTON,VA 23681, USA. NR 0 TC 3 Z9 4 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 529 EP 538 DI 10.2514/3.46752 PG 10 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600011 ER PT J AU MURRI, DG SHAH, GH DICARLO, DJ TRILLING, TW AF MURRI, DG SHAH, GH DICARLO, DJ TRILLING, TW TI ACTUATED FOREBODY STRAKE CONTROLS FOR THE F-18 HIGH-ALPHA RESEARCH VEHICLE SO JOURNAL OF AIRCRAFT LA English DT Article AB A series of ground-based studies have been conducted to develop actuated forebody strake controls for flight-test evaluations using the NASA F-18 High-Alpha Research Vehicle (HARV). The actuated forebody strakes were designed to provide increased levels of Saw control at high angles of attack where conventional rudders become ineffective. Results are presented from tests conducted with the night-test strake design, including static and dynamic wind-tunnel tests, transonic wind-tunnel tests, full-scale wind-tunnel tests, pressure surveys, and flow visualization tests, Results from these studies show that a pair of conformal actuated forebody strakes applied to the F-18 HARV can provide a powerful and precise Saw control device at high angles of attack, The preparations for flight testing are described, including the fabrication of flight hardware and the development of aircraft flight control laws. The primary objectives of the night tests are to provide night validation of the ground-based studies and to evaluate the use of this type of control to enhance fighter aircraft maneuverability. RP MURRI, DG (reprint author), NASA,LANGLEY RES CTR,DIV FLIGHT DYNAM & CONTROL,VEHICLE DYNAM BRANCH,M-S 355,HAMPTON,VA 23681, USA. NR 0 TC 3 Z9 4 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 555 EP 562 DI 10.2514/3.46755 PG 8 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600014 ER PT J AU BUDD, GD GILMAN, RL EICHSTEDT, D AF BUDD, GD GILMAN, RL EICHSTEDT, D TI OPERATIONAL AND RESEARCH ASPECTS OF A RADIO-CONTROLLED MODEL FLIGHT TEST PROGRAM SO JOURNAL OF AIRCRAFT LA English DT Article AB The operational and research aspects of a subscale, radio-controlled model flight-test program are presented. By using low-cost free-flying models, an approach was developed for obtaining research-quality vehicle performance and aerodynamic information. The advantages and limitations learned by applying this approach to a specific night-test program are described. The research quality of the data acquired shows that model flight testing is practical for obtaining consistent and repeatable flight data. RP BUDD, GD (reprint author), NASA,DRYDEN FLIGHT RES CTR,EDWARDS AFB,CA 93523, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 583 EP 589 DI 10.2514/3.46759 PG 7 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600018 ER PT J AU EKATERINARIS, JA CHANDRASEKHARA, MS PLATZER, MF AF EKATERINARIS, JA CHANDRASEKHARA, MS PLATZER, MF TI ANALYSIS OF LOW-REYNOLDS-NUMBER AIRFOIL FLOWS SO JOURNAL OF AIRCRAFT LA English DT Article AB Compressible steady and unsteady flowfields over a NACA 0012 airfoil at transitional Reynolds numbers are investigated. Comparisons with recently obtained experimental data are used to evaluate the ability of a numerical solution based on the compressible thin layer Navier-Stokes approximation, augmented with a transition model, to simulate transitional flow features, The discretization is obtained with an upwind-biased, factorized, iterative scheme. Transition onset is estimated using an empirical criterion based on the computed mean flow boundary-layer quantities. The transition length is computed from an empirical formula. The incorporation of transition modeling enables the prediction of the experimentally observed leading-edge separation bubbles. Results for steady airfoil flows at fixed angles of attack and for oscillating airfoils are presented. RP EKATERINARIS, JA (reprint author), USN,POSTGRAD SCH,NASA,JOINT INST AERONAUT,DEPT AERONAUT & ASTRONAUT,MONTEREY,CA 93943, USA. NR 0 TC 7 Z9 7 U1 1 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAY-JUN PY 1995 VL 32 IS 3 BP 625 EP 630 DI 10.2514/3.46765 PG 6 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600024 ER PT J AU ROSS, JC STORMS, BL CARRANNANTO, PG AF ROSS, JC STORMS, BL CARRANNANTO, PG TI LIFT-ENHANCING TABS ON MULTIELEMENT AIRFOILS SO JOURNAL OF AIRCRAFT LA English DT Article AB The use of flat-plate tabs (similar to Gurney flaps) to enhance the lift of multielement airfoils is extended here by placing them on the pressure side and near the trailing edge of the main element rather than just on the furthest downstream wing element. The tabs studied range in height from 0.125 to 1.25% of the airfoil reference chord. In practice, such tabs would be retracted when the high-lift system is stowed. The effectiveness of the concept was demonstrated experimentally and computationally on a two-dimensional NACA 63(2)-215 Mod B airfoil with a single-slotted, 30%-chord flap. Both the experiments and computations showed that the tabs significantly increase the lift at a given angle of attack and the maximum lift coefficient of the airfoil. The computational results showed that the increased lift was a result of additional turning of the flow by the tab that reduced or eliminated flow separation on the flap. The best configuration tested, a 0.5%-chord tab placed 0.5% chord upstream of the trailing edge of the main element, increased the maximum lift coefficient of the airfoil by 12% and the maximum lift-to-drag ratio by 40%. RP ROSS, JC (reprint author), NASA,AMES RES CTR,AMES DIV,FIXED WING AERODYNAM BRANCH,MOFFETT FIELD,CA 94035, USA. NR 0 TC 18 Z9 21 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 MAY-JUN PY 1995 VL 32 IS 3 BP 649 EP 655 DI 10.2514/3.46769 PG 7 WC Engineering, Aerospace SC Engineering GA RA436 UT WOS:A1995RA43600028 ER PT J AU RUPPERT, J AF RUPPERT, J TI A DELAUNAY REFINEMENT ALGORITHM FOR QUALITY 2-DIMENSIONAL MESH GENERATION SO JOURNAL OF ALGORITHMS LA English DT Article; Proceedings Paper CT 4th Annual ACM/SIAM Symposium on Discrete Algorithms (SODA) CY JAN, 1993 CL AUSTIN, TX SP ASSOC COMP MACHINERY, SOC IND APPL MATH ID VORONOI DIAGRAMS AB We present a simple new algorithm for triangulating polygons and planar straightline graphs, It provides ''shape'' and ''size'' guarantees: All triangles have a bounded aspect ratio. The number of triangles is within a constant factor of optimal. Such ''quality'' triangulations are desirable as meshes for the finite element method, in which the running time generally increases with the number of triangles, and where the convergence and stability may be hurt by very skinny triangles. The technique we use-successive refinement of a Delaunay triangulation-extends a mesh generation technique of Chew by allowing triangles of varying sizes. Compared with previous quadtree-based algorithms for quality mesh generation, the Delaunay refinement approach is much simpler and generally produces meshes with fewer triangles. We also discuss an implementation of the algorithm and evaluate its performance on a variety of inputs. (C) 1995 Academic Press, Inc. C1 HEWLETT PACKARD LABS,PALO ALTO,CA. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. COMP SCI CORP,EL SEGUNDO,CA 90245. UNIV CALIF BERKELEY,DIV COMP SCI,BERKELEY,CA. NR 21 TC 304 Z9 324 U1 0 U2 13 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0196-6774 J9 J ALGORITHM JI J. Algorithms PD MAY PY 1995 VL 18 IS 3 BP 548 EP 585 DI 10.1006/jagm.1995.1021 PG 38 WC Computer Science, Theory & Methods; Mathematics, Applied; Logic SC Computer Science; Mathematics; Science & Technology - Other Topics GA RB984 UT WOS:A1995RB98400007 ER PT J AU HUTCHISON, KD HARDY, KR GAO, BC AF HUTCHISON, KD HARDY, KR GAO, BC TI IMPROVED DETECTION OF OPTICALLY THIN CIRRUS CLOUDS IN NIGHTTIME MULTISPECTRAL METEOROLOGICAL SATELLITE IMAGERY USING TOTAL INTEGRATED WATER-VAPOR INFORMATION SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WINDOW; CLASSIFICATION; TEMPERATURE; EMISSIVITY; AVHRR AB The accurate identification of optically thin cirrus clouds in global meteorological satellite imagery by automated cloud analysis algorithms is critical to environmental remote sensing studies, such as those related to climate change. While significant improvements have been realized with the arrival of multispectral, meteorological satellite imagery, collected by NOAA's Advanced Very High Resolution Radiometer (AVHRR), difficulties can be encountered when attempting to make pixel-level cloud decisions over large and diverse geographic areas found around the globe. These problems are due, in part, to the effects of atmospheric attenuation on cloud spectral signatures, caused primarily by variations in water vapor, since the signatures of water vapor and optically thin cirrus are similar in the nighttime AVHRR infrared channels. In this paper, the authors describe an improved thin-cirrus detection technique that uses the brightness temperature differences between AVHRR channel 3 and channel 5 along with total integrated water vapor information. It is concluded that algorithms must accurately compensate for the impact of water vapor on cloud spectral signatures for enhanced detection of optically thin cirrus clouds in nighttime AVHRR imagery. C1 NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,GREENBELT,MD 20771. RP HUTCHISON, KD (reprint author), LOCKHEED MISSILES & SPACE CO INC,CTR REMOTE ENVIRONM SENSING TECHNOL,AUSTIN DIV,AUSTIN,TX 78760, USA. NR 18 TC 21 Z9 21 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 1995 VL 34 IS 5 BP 1161 EP 1168 DI 10.1175/1520-0450(1995)034<1161:IDOOTC>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QW518 UT WOS:A1995QW51800015 ER PT J AU REDDY, M MONDRY, MJ RODWELL, MJW MARTIN, SC MULLER, RE SMITH, RP CHOW, DH SCHULMAN, JN AF REDDY, M MONDRY, MJ RODWELL, MJW MARTIN, SC MULLER, RE SMITH, RP CHOW, DH SCHULMAN, JN TI FABRICATION AND DC, MICROWAVE CHARACTERISTICS OF SUBMICRON SCHOTTKY-COLLECTOR ALAS/IN0.53GA0.47AS/INP RESONANT-TUNNELING DIODES SO JOURNAL OF APPLIED PHYSICS LA English DT Note ID OSCILLATIONS; GHZ C1 CALTECH,JET PROP LAB,CTR SPACE MICROELECTR TECHNOL,PASADENA,CA 91109. HUGHES RES LABS,MALIBU,CA 90265. RP REDDY, M (reprint author), UNIV CALIF SANTA BARBARA,DEPT ELECT & COMP ENGN,SANTA BARBARA,CA 93106, USA. NR 6 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1995 VL 77 IS 9 BP 4819 EP 4821 DI 10.1063/1.359405 PG 3 WC Physics, Applied SC Physics GA QV479 UT WOS:A1995QV47900091 ER PT J AU EDGERTON, VR ZHOU, MY OHIRA, Y KLITGAARD, H JIANG, B BELL, G HARRIS, B SALTIN, B GOLLNICK, PD ROY, RR DAY, MK GREENISEN, M AF EDGERTON, VR ZHOU, MY OHIRA, Y KLITGAARD, H JIANG, B BELL, G HARRIS, B SALTIN, B GOLLNICK, PD ROY, RR DAY, MK GREENISEN, M TI HUMAN FIBER SIZE AND ENZYMATIC-PROPERTIES AFTER 5 AND 11 DAYS OF SPACEFLIGHT SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE WEIGHTLESSNESS; SUCCINATE DEHYDROGENASE ACTIVITY; ALPHA-GLYCEROPHOSPHATE DEHYDROGENASE ACTIVITY; MYOFIBRILLAR ADENOSINE-TRIPHOSPHATASE ACTIVITY; BIOPSIES; CAPILLARY DENSITY; FIBER TYPES ID RAT SKELETAL-MUSCLE; LIMB SUSPENSION; SOLEUS MUSCLE; EXERCISE; ENZYMES; TIME AB Biopsies from the vastus lateralis muscle were obtained from three astronauts before and after two 5-day flights and from five astronauts before and after one 11-day flight (space shuttle flights: STS-32, -33, and -34). Muscle fibers from two separate samples from each biopsy were classified as type I and II or as type I, IIA, and IIB by using qualitative myofibrillar adenosinetriphosphatase (ATPase) staining. Cross-sectional area (CSA), number of capillaries per fiber, and the activities of succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar ATPase were determined from one sample of fibers of each myofibrillar ATPase type. Postflight biopsies had 6-8% fewer type I fibers than preflight. Mean fiber CSAs were 16-36% smaller after the 11-day flight with the relative effect being type IIB > IIA > I. Mean fiber CSAs were 11 and 24% smaller in type I and II fibers after 5 days of flight. Myofibrillar ATPase activities increased in type II but not in type I fibers after flight, whereas SDH activity was unaffected in either fast or slow fibers. GPD activity in type I fibers was similar to 80% higher (P > 0.05) postflight compared with preflight. Myofibrillar ATPase/SDH ratios in type II fibers were higher after than before flight, suggesting that some fast fibers were more susceptible to fatigue after flight. The GPD/SDH ratios were elevated in some type I fibers after spaceflight. The number of capillaries per fiber was 24% lower after than before flight, whereas the number of capillaries per unit CSA of muscle tissue was unchanged. These data suggest that adaptations in the size, metabolic properties, and vascularity of muscle fibers can occur rapidly in the space environment. These adaptations were qualitatively similar to those observed in animals after actual or simulated spaceflight conditions for short periods. C1 UNIV CALIF LOS ANGELES,BRAIN RES INST,LOS ANGELES,CA 90095. UNIV COPENHAGEN,AUGUST KROGH INST,DEPT HUMAN PHYSIOL,DK-2200 COPENHAGEN,DENMARK. NATL INST FITNESS & SPORT,DEPT PHYSIOL & BIOMECH,KANOYA,KAGOSHIMA 89123,JAPAN. UNIV ALBERTA,DEPT PHYS THERAPY,EDMONTON,AB T6G 2G4,CANADA. NASA,LYNDON B JOHNSON SPACE CTR,ASTRONAUT CORPS & EXERCISE COUNTERMEASURES PROJEC,HOUSTON,TX 77058. WASHINGTON STATE UNIV,COLL VET MED,PULLMAN,WA 99163. RP EDGERTON, VR (reprint author), UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI,1804 LIFE SCI,405 HILGARD AVE,LOS ANGELES,CA 90095, USA. NR 41 TC 193 Z9 197 U1 2 U2 6 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 MAY PY 1995 VL 78 IS 5 BP 1733 EP 1739 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA QY605 UT WOS:A1995QY60500016 PM 7649906 ER PT J AU LAAKSO, H AGGSON, TL HERRERO, FA PFAFF, RF HANSON, WB AF LAAKSO, H AGGSON, TL HERRERO, FA PFAFF, RF HANSON, WB TI VERTICAL NEUTRAL WIND IN THE EQUATORIAL F-REGION DEDUCED FROM ELECTRIC-FIELD AND ION DENSITY-MEASUREMENTS SO JOURNAL OF ATMOSPHERIC AND TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT National-Science-Foundation CEDAR (Coupling, Energetics and Dynamics of Atmospheric Regions) Summer Meeting CY JUN, 1992 CL BOULDER, CO SP NATL SCI FDN ID BUBBLES; IONOSPHERE; GRADIENTS; DYNAMICS; ARECIBO AB DC electric field and ion density measurements near density depletion regions (that is, equatorial plasma bubbles) are used to estimate the vertical neutral wind speed. The measured zonal electric field in a series of density depletions crossed by the San Marco D satellite at 01.47-01.52 UT on 25 October 1988, can be explained if a downward neutral wind of 15-30 m s(-1) exists. Simultaneously, the F-region plasma was moving downward at a speed of 30-50 m s(-1). These events appear in the local lime sector of 23.00-23.15 in which strong downward neutral winds may occur. Indeed, airglow measurements suggest that downward neutral velocities of 25-50 m s(-1) are possible at times near midnight in the equatorial F-region. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. UNIV TEXAS,CTR SPACE SCI,RICHARDSON,TX 75083. RI Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 14 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 0021-9169 J9 J ATMOS TERR PHYS JI J. Atmos. Terr. Phys. PD MAY PY 1995 VL 57 IS 6 BP 645 EP 651 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QM458 UT WOS:A1995QM45800007 ER PT J AU KIM, JT WANG, H TSAI, CC BAHNS, JT STWALLEY, WC JONG, G LYYRA, AM AF KIM, JT WANG, H TSAI, CC BAHNS, JT STWALLEY, WC JONG, G LYYRA, AM TI OBSERVATION OF THE 4-(3)SIGMA(+)(G), 3-(3)PI(G), 2-(3)DELTA(G), AND B-(3)PI(U) STATES OF K-39(2) BY PERTURBATION FACILITATED OPTICAL-OPTICAL DOUBLE-RESONANCE SPECTROSCOPY SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID K2; 1(3)DELTA-G; 2(3)PI-G C1 UNIV CONNECTICUT,INST SCI MAT,STORRS,CT 06269. UNIV IOWA,DEPT PHYS & ASTRON,IOWA CITY,IA 52246. CALTECH,JET PROP LAB,PASADENA,CA 91109. TEMPLE UNIV,DEPT PHYS,PHILADELPHIA,PA 19122. RP KIM, JT (reprint author), UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06269, USA. NR 12 TC 30 Z9 31 U1 0 U2 5 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 MAY 1 PY 1995 VL 102 IS 17 BP 6646 EP 6652 DI 10.1063/1.469137 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA QU836 UT WOS:A1995QU83600003 ER PT J AU BRADLEY, KS MCCABE, P SCHATZ, GC WALCH, SP AF BRADLEY, KS MCCABE, P SCHATZ, GC WALCH, SP TI A THEORETICAL-STUDY OF THE NH+NO REACTION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID AMMONIA FLAMES; GAS-PHASE; H-ATOM; NO; NH; KINETICS; REPRESENTATION; MECHANISM; DYNAMICS; PRODUCT C1 NASA, AMES RES CTR, INST THERMOSCI, MOFFETT FIELD, CA 94035 USA. RP NORTHWESTERN UNIV, DEPT CHEM, 2145 SHERIDAN RD, EVANSTON, IL 60208 USA. RI McCabe, Patrick/M-3718-2013 OI McCabe, Patrick/0000-0003-2538-4920 NR 33 TC 33 Z9 33 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1995 VL 102 IS 17 BP 6696 EP 6705 DI 10.1063/1.469143 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA QU836 UT WOS:A1995QU83600009 ER PT J AU GERSTELL, MF CRISP, J CRISP, D AF GERSTELL, MF CRISP, J CRISP, D TI RADIATIVE FORCING OF THE STRATOSPHERE BY SO2 GAS, SILICATE ASH, AND H2SO4 AEROSOLS SHORTLY AFTER THE 1982 ERUPTIONS OF EL CHICHON SO JOURNAL OF CLIMATE LA English DT Article ID PLANETARY ATMOSPHERES; MULTIPLE-SCATTERING; MARTIAN ATMOSPHERE; SIZE DISTRIBUTIONS; OPTICAL-PROPERTIES; MIDDLE ATMOSPHERE; VOLCANIC-ERUPTION; VENUS MESOSPHERE; TOTAL OZONE; CLOUD AB The 1982 eruptions of the El Chichon volcano injected large quantities of sulfur dioxide gas and silicate ash into the stratosphere. Several studies have shown that the long-lived sulfuric acid aerosols derived from these volcanic effluents produced measurable changes in the radiative heating rates and the global circulation. The radiative and dynamical perturbations associated with the short-lived but more strongly absorbing sulfur dioxide and ash clouds have received much less attention. The authors therefore used an atmospheric radiative transfer model and observations collected by satellites, aircraft, and ground-based observers to estimate the amplitudes of the stratospheric radiative heating rate perturbations produced by each of these components during the first few weeks after the El Chichon eruption. One week after the 4 April 1982 eruption, net radiative heating rate perturbations exceeding 20 K per day were found at altitudes near 26 km. The absorption of sunlight by the silicate ash accounts for the majority of this heating. The sulfur dioxide gas and sulfuric acid aerosols each produced net heating perturbations that never exceeded 3 K per day. In spite of the intense heating by the ash, observations indicate that stratospheric temperatures never increased by more than a few degrees Kelvin. The authors therefore concluded that this radiative heating was largely balanced by upwelling and adiabatic cooling. The amplitude and spatial extent of this upwelling was estimated with a diagnostic, two-dimensional dynamical model. The ash heating rates may have been balanced by a global enhancement in the stratospheric meridional circulation, with zonally averaged upward velocities of about 1 cm sec(-1) near the latitude of the plume. This enhanced stratospheric circulation persisted only for a few weeks but it may have played a major role in the vertical and horizontal dispersal of the plume. The vertical transport needed to balance the heating by sulfur dioxide gas was only 5%-10% as large, but this perturbation may have produced a 2-km increase in the altitude of the plume. These results suggest that the radiative forcing by the ash and the sulfur dioxide gas should be included in more comprehensive models of the plume evolution. They also suggest that particle size distributions inferred from ash fallout rates could be wrong if the upwelling associated with this radiative heating is not considered. C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. RP GERSTELL, MF (reprint author), CALTECH,DEPT PLANETARY SCI,PASADENA,CA 91125, USA. RI Crisp, Joy/H-8287-2016 OI Crisp, Joy/0000-0002-3202-4416 NR 68 TC 10 Z9 10 U1 0 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 MAY PY 1995 VL 8 IS 5 BP 1060 EP 1070 DI 10.1175/1520-0442(1995)008<1060:RFOTSB>2.0.CO;2 PN 1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RB231 UT WOS:A1995RB23100007 ER PT J AU HUFFMAN, GJ ADLER, RF RUDOLF, B SCHNEIDER, U KEEHN, PR AF HUFFMAN, GJ ADLER, RF RUDOLF, B SCHNEIDER, U KEEHN, PR TI GLOBAL PRECIPITATION ESTIMATES BASED ON A TECHNIQUE FOR COMBINING SATELLITE-BASED ESTIMATES, RAIN-GAUGE ANALYSIS, AND NWP MODEL PRECIPITATION INFORMATION SO JOURNAL OF CLIMATE LA English DT Article ID SCALE AB The ''satellite-gauge-model'' (SGM) technique is described for combining precipitation estimates from microwave satellite data, infrared satellite data, rain gauge analyses, and numerical weather prediction models into improved estimates of global precipitation. Throughout, monthly estimates on a 2.5 degrees X 2.5 degrees lat-long grid are employed. First, a multisatellite product is developed using a combination of low-orbit microwave and geosynchronous-orbit infrared data in the latitude range 40 degrees N-40 degrees S (the adjusted geosynchronous precipitation index) and low-orbit microwave data alone at higher latitudes. Then the rain gauge analysis is brought in, weighting each field by its inverse relative error variance to produce a nearly global, observationally based precipitation estimate. To produce a complete global estimate, the numerical model results are used to fill data voids in the combined satellite-gauge estimate. Our sequential approach to combining estimates allows a user to select the multisatellite estimate, the satellite-gauge estimate, or the full SGM estimate (observationally based estimates plus the model information). The primary limitation in the method is imperfections in the estimation of relative error for the individual fields. The SGM results for one year of data (July 1987 to June 1988) show important differences from the individual estimates, including model estimates as well as climatological estimates. In general, the SGM results are drier in the subtropics than the model and climatological results, reflecting the relatively dry microwave estimates that dominate the SGM in oceanic regions. C1 SCI SYST & APPLICAT INC,GREENBELT,MD. GPCC,DEUTSCH WETTDIENST,OFFENBACH,GERMANY. RP HUFFMAN, GJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. RI Huffman, George/F-4494-2014 OI Huffman, George/0000-0003-3858-8308 NR 15 TC 276 Z9 285 U1 1 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1995 VL 8 IS 5 BP 1284 EP 1295 DI 10.1175/1520-0442(1995)008<1284:GPEBOA>2.0.CO;2 PN 2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RB232 UT WOS:A1995RB23200003 ER PT J AU CHEHBOUNI, A NJOKU, EG LHOMME, JP KERR, YH AF CHEHBOUNI, A NJOKU, EG LHOMME, JP KERR, YH TI APPROACHES FOR AVERAGING SURFACE PARAMETERS AND FLUXES OVER HETEROGENEOUS TERRAIN SO JOURNAL OF CLIMATE LA English DT Article ID BOUNDARY-LAYER; CIRCULATIONS; VEGETATION; MODELS; IMPACT; ENERGY AB Successful prediction of possible climate change depends on realistic parameterization of land surface processes in climate models. Such parameterizations must take appropriate account of the heterogeneities that are found in most earth surfaces. In this study, different averaging strategies for aggregating patch-scale heterogeneities to scales that are appropriate for mesoscale and climate model grids have been explored. A simple model for estimating area-average ''effective'' surface nux parameters is evaluated. The model satisfies the energy balance equation and leads to a set of relationships between local and effective parameters in the governing equations for the surface energy balance. One outcome is that the resulting effective surface temperature is not a simple area-weighted average of component temperatures, but is a function of a specific combination of different resistances of the individual surface elements. A set of heterogeneous surfaces has been simulated to study the effective fluxes obtained using the described model. A comparison with results obtained by other investigators using different averaging methods is also performed. C1 CALTECH,JET PROP LAB,PASADENA,CA. CNES,CESBIO,TOULOUSE,FRANCE. RP CHEHBOUNI, A (reprint author), ORSTOM,HYDROL LAB,911 AV AGROPOLIS,BP 5045,F-34032 MONTPELLIER,FRANCE. RI Lhomme, Jean Paul /G-7236-2015 NR 16 TC 34 Z9 34 U1 1 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY PY 1995 VL 8 IS 5 BP 1386 EP 1393 DI 10.1175/1520-0442(1995)008<1386:AFASPA>2.0.CO;2 PN 2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA RB232 UT WOS:A1995RB23200010 ER PT J AU CARPENTER, MH OTTO, J AF CARPENTER, MH OTTO, J TI HIGH-ORDER CYCLE-DIFFERENCE TECHNIQUES - AN ALTERNATIVE TO FINITE-DIFFERENCES SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article AB The summation-by-parts energy norm is used to establish a new class of high-order finite-difference techniques referred to here as ''cycle-difference'' techniques. These techniques are constructed cyclically from stable subelements and require no special numerical procedures near the boundaries; when coupled with the simultaneous approximation term (SAT) boundary treatment, they are time asymptotically stable for an arbitrary hyperbolic system. These techniques are similar to spectral multi-domain techniques and are ideally suited for parallel implementation, but they do not require special collocation points. The principal focus of th is work is on methods of sixth-order formal accuracy or less; however, these methods could be extended in principle to any arbitrary order of accuracy. (c) 1995 Academic Press, Inc. C1 NASA,LANGLEY RES CTR,MULTIDISCIPLINARY DESIGN OPTIMIZAT BRANCH,HAMPTON,VA 23681. RP CARPENTER, MH (reprint author), NASA,LANGLEY RES CTR,AERODYNAM & ACOUST METHODS BRANCH,HAMPTON,VA 23681, USA. NR 15 TC 4 Z9 4 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1995 VL 118 IS 2 BP 242 EP 260 DI 10.1006/jcph.1995.1096 PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QV550 UT WOS:A1995QV55000006 ER PT J AU JUSTIZ, CR SEGA, RM DALTON, C AF JUSTIZ, CR SEGA, RM DALTON, C TI A METHOD FOR NEAR-FIELD COMPUTATION OF COUPLED WEAKLY IONIZED PLASMA FLOWS IN LOW-EARTH-ORBIT SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID MONTE-CARLO SIMULATION AB The problem of wake effects, particularly the near wake, from spacecraft in low Earth orbit is of increasing interest. The flow simulation reported herein combines the fully coupled effects of neutral particle flow, plasma flow, electromagnetic field effects, and spacecraft charging. The simulation necessarily allows for chemically reacting flows (associative ionization, dissociation, and chain exchange) and for thermal accommodation at a spacecraft surface. Due to the highly coupled nature of the flow physics, a full solution simultaneous approach is used. This is required due to the need for extremely high resolution results for the near wake region. In this approach, the neutral flow is modeled using a direct simulation Monte Carlo technique. The charged particles are modeled using a particle approach to solve the Poisson equation. A technique of having a separate neutral-particle grid and a charged-particle grid is used. Neutral and charged particles are allowed collisional interaction. During one time step, the neutral-particle-move process occurs separately from the charged-particle-move process which is accomplished in the presence of the electromagnetic field. A major advantage of the technique is that results may be obtained with the dominant effects of orbital flows simultaneously modeled. A major disadvantage is that the technique is computationally expensive. Flow calculations for the neutral- and charged-particle cases are compared to independent and uncoupled computational simulations to confirm their accuracy. The solution procedure and technique are presented for several types of flows at orbital altitudes of 250 and 500 km, Excellent agreement with previously verified computational algorithms has been obtained for the case of neutral particle flow and charged-particle flow. Results for the full flow simulation are presented for 250 and 500 km. (c) 1995 Academic Press, Inc. C1 UNIV HOUSTON,DEPT MECH ENGN,HOUSTON,TX 77204. RP JUSTIZ, CR (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1995 VL 118 IS 2 BP 278 EP 293 DI 10.1006/jcph.1995.1099 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QV550 UT WOS:A1995QV55000009 ER PT J AU LIOU, MS AF LIOU, MS TI AN EXTENDED LAGRANGIAN METHOD SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID FLOW SPEEDS; SCHEME AB A unique formulation of describing fluid motion is presented. The method, referred to as ''extended Lagrangian method,'' is interesting from both theoretical and numerical points of view. The formulation offers accuracy in numerical solution by avoiding numerical diffusion resulting from mixing of fluxes in the Eulerian description. The present method and the Arbitrary Lagrangian-Eulerian (ALE) method have a similarity in spirit-eliminating the cross-streamline numerical diffusion. For this purpose, we suggest a simple grid constraint condition and utilize an accurate discretization procedure. This grid constraint is only applied to the transverse cell face parallel to the local stream velocity, and hence our method for the steady state problems naturally reduces to the streamline-curvature method, without explicitly solving the steady streamline-coordinate equations formulated a priori. Unlike the Lagrangian method proposed by Loh and Hui which is valid only for steady supersonic flows, the present method is general and capable of treating subsonic flows and supersonic flows as well as unsteady flows, simply by invoking in the same code an appropriate grid constraint suggested in this paper. The approach is found to be robust and stable. It automatically adapts to flow features without resorting to clustering, thereby maintaining rather uniform grid spacing throughout and large time step. Moreover, the method is shown to resolve multi-dimensional discontinuities with a high level of accuracy, similar to that found in one-dimensional problems. (c) 1995 Academic Press. Inc. RP LIOU, MS (reprint author), NASA,LEWIS RES CTR,DIV INTERNAL FLUID MECH,CLEVELAND,OH 44135, USA. NR 24 TC 10 Z9 11 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1995 VL 118 IS 2 BP 294 EP 309 DI 10.1006/jcph.1995.1100 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QV550 UT WOS:A1995QV55000010 ER PT J AU BERTOLOTTI, FP JOSLIN, RD AF BERTOLOTTI, FP JOSLIN, RD TI EFFECT OF FAR-FIELD BOUNDARY-CONDITIONS ON BOUNDARY-LAYER-TRANSITION SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Note ID NAVIER-STOKES EQUATIONS; NUMERICAL-SIMULATION; STABILITY C1 NASA,LANGLEY RES CTR,INST COMP APPL SCI & ENGN,HAMPTON,VA 23681. NR 13 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY PY 1995 VL 118 IS 2 BP 392 EP 395 DI 10.1006/jcph.1995.1109 PG 4 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA QV550 UT WOS:A1995QV55000019 ER PT J AU NADARAJAH, A FORSYTHE, EL PUSEY, ML AF NADARAJAH, A FORSYTHE, EL PUSEY, ML TI THE AVERAGED FACE GROWTH-RATES OF LYSOZYME CRYSTALS - THE EFFECT OF TEMPERATURE SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID TETRAGONAL LYSOZYME; PROTEIN CRYSTALLIZATION; KINETICS; MICROSCOPY; SOLUBILITY AB Measurements of the averaged or macroscopic face growth rates of lysozyme crystals are reported here for the (110) face of tetragonal lysozyme, at three sets of pH and salt concentrations, with temperatures over a 4-22 degrees C range for several protein concentrations. The growth rate trends with supersaturation were similar to previous microscopic growth rate measurements. However, it was found that at high supersaturations the growth rates attain a maximum and then start decreasing. No ''dead zone'' was observed but the growth rates were found to approach zero asymptotically at very low supersaturations. The growth rate data also displayed a dependence on pH and salt concentration which could not be characterized solely by the supersaturation. A complete mechanism for lysozyme crystal growth, involving the formation of an aggregate growth unit, mass transport of the growth unit to the crystal interface and faceted crystal growth by growth unit addition, is suggested. Such a mechanism may provide a more consistent explanation for the observed growth rate trends than those suggested by other investigators. The nutrient solution interactions leading to the formation of the aggregate growth unit may, thus, be as important as those occurring at the crystal interface and may account for the differences between small molecule and protein crystal growth. C1 UNIV ALABAMA,DEPT CHEM ENGN,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,BIOPHYS BRANCH ES76,HUNTSVILLE,AL 35812. NR 43 TC 66 Z9 67 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 MAY PY 1995 VL 151 IS 1-2 BP 163 EP 172 DI 10.1016/0022-0248(95)00036-4 PG 10 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA RD987 UT WOS:A1995RD98700023 ER PT J AU LANE, HW NILLEN, JL KLOERIS, VL AF LANE, HW NILLEN, JL KLOERIS, VL TI FOLIC-ACID CONTENT IN THERMOSTABILIZED AND FREEZE-DRIED SPACE-SHUTTLE FOODS SO JOURNAL OF FOOD SCIENCE LA English DT Article DE BROCCOLI; GREEN BEANS; CAULIFLOWER; FREEZE-DRYING; FOLACIN ID MICROBIOLOGICAL ASSAY; LACTOBACILLUS-CASEI; FOLATE; HYDROLASE; FOLACIN AB This study was designed to determine whether freeze-dried and thermostabilized foods on a space shuttle contain adequate folate and to investigate any effects of freeze-drying on folacin. Frozen vegetables were analyzed after three stages of processing: thawed; cooked; and rehydrated. Thermostabilized items were analyzed as supplied with no further processing, Measurable folate decreased in some freeze-dried vegetables and increased in others. Folacin content of thermostabilized food items was comparable with published values. We concluded that although the folacin content of some freeze-dried foods was low, adequate folate is available from the shuttle menu to meet RDA guidelines. C1 KRUG LIFE SCI,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,SYST DEV SECT,HOUSTON,TX 77058. RP LANE, HW (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,MAIL CODE SD4,HOUSTON,TX 77058, USA. NR 30 TC 2 Z9 2 U1 0 U2 2 PU INST FOOD TECHNOLOGISTS PI CHICAGO PA SUITE 300 221 N LASALLE ST, CHICAGO, IL 60601-1291 SN 0022-1147 J9 J FOOD SCI JI J. Food Sci. PD MAY-JUN PY 1995 VL 60 IS 3 BP 538 EP 540 DI 10.1111/j.1365-2621.1995.tb09821.x PG 3 WC Food Science & Technology SC Food Science & Technology GA RC227 UT WOS:A1995RC22700026 PM 11538308 ER PT J AU SONWALKAR, VS INAN, US AGGSON, TL FARRELL, WM PFAFF, R AF SONWALKAR, VS INAN, US AGGSON, TL FARRELL, WM PFAFF, R TI FOCUSING OF NONDUCTED WHISTLERS BY THE EQUATORIAL ANOMALY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INDUCED ELECTRON-PRECIPITATION; MAGNETOSPHERE; IONS AB Impulsive ELF/VLF electric field bursts observed by the vector electric field instrument (VEFI) on the Dynamics Explorer 2 (DE 2) satellite on almost every crossing of the geomagnetic equator in the evening hours are interpreted as originating in lightning discharges. These signals that peak in intensity near the magnetic equator are observed within 5-20 degrees latitude of the geomagnetic equator at altitudes of 300-500 km with amplitudes of the order of similar to mV/m in the 512- to 1024-Hz frequency band of the VEFI instrument. Whistler-mode ELF/VLF wave propagation through a horizontally stratified ionosphere predicts strong attenuation of subionospheric signals reaching the equator at low altitudes. However, ray tracing analysis shows that the presence of the equatorial density anomaly, commonly observed in the upper ionosphere during evening hours, leads to the focusing of the wave energy from lightning near the geomagnetic equator at low altitudes, thus accounting for all observed aspects of the phenomenon. The observations presented here indicate that during certain hours in the evening, almost all the energy input from lightning discharges entering the ionosphere at <30 degrees latitude remains confined to a small region (in altitude and latitude) near the geomagnetic equator. The net wideband electric field, extrapolated from the observed electric field values in the 512- to 1024-Hz band, can be similar to 10 mV/m or higher. These strong electric fields generated in the ionosphere by lightning at local evening times may be important for the equatorial electrodynamics of the ionosphere. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SONWALKAR, VS (reprint author), STANFORD UNIV,STAR LAB,STANFORD,CA 94305, USA. RI Pfaff, Robert/F-5703-2012; Farrell, William/I-4865-2013 OI Pfaff, Robert/0000-0002-4881-9715; NR 31 TC 10 Z9 10 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1995 VL 100 IS A5 BP 7783 EP 7790 DI 10.1029/94JA02756 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY981 UT WOS:A1995QY98100018 ER PT J AU MELENDEZALVIRA, DJ TORR, DG RICHARDS, PG SWIFT, WR TORR, MR BALDRIDGE, T RASSOUL, H AF MELENDEZALVIRA, DJ TORR, DG RICHARDS, PG SWIFT, WR TORR, MR BALDRIDGE, T RASSOUL, H TI SENSITIVITY OF THE 6300 ANGSTROM TWILIGHT AIRGLOW TO NEUTRAL COMPOSITION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID IONOSPHERIC PHOTOELECTRON FLUX; EXCITATION CROSS-SECTIONS; GROUND-BASED MEASUREMENTS; NOCTURNAL F-REGION; ATOMIC OXYGEN; O(1D) ATOMS; DISSOCIATIVE RECOMBINATION; COLLISIONAL EXCITATION; SOLAR CYCLE-21; EMISSION AB The field line interhemispheric plasma (FLIP) model is used to study the 6300 Angstrom line intensity measured during three morning twilights from the McDonald Observatory in Texas. The Imaging Spectrometric Observatory (ISO) measured the 6300 Angstrom intensity during the winter of 1987 and the spring and summer of 1988. The FLIP model reproduces the measured intensity and its variation through the twilight well on each day using neutral densities from the MSIS-86 empirical model. This is in spite of the fact that different component sources dominate the integrated volume emission rate on each of the days analyzled. The sensitivity of the intensity to neutral composition is computed by varying the N-2, O-2 and O densities in the FLIP model and comparing to the intensity computed with the unmodified MSIS-86 densities. The ion densities change self-consistently. Thus the change in neutral composition also changes the electron density. The F2 peak height is unchanged in the model runs for a given day. The intensity changes near 100 degrees SZA are comparable to within 10% when either [O-2], [N-2] or [O] is changed, regardless of which component source is dominant. There is strong sensitivity to changes in [N-2] when dissociative recombination is dominant, virtually no change in the nighttime (SZA greater than or equal to 108 degrees) intensity with [O-2] doubled, and sensitivity of over 50% to doubling or halving [O] at night. When excitation by conjugate photoelectrons is the dominant nighttime component source, the relative intensity change with [O] doubled of halved is very small. This study shows the strong need for simultaneous measurements of electron density and of emissions proportional to photoelectron fluxes if the 6300 Angstrom twilight airglow is to be used to retrieve neutral densities. C1 UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,OPT AERON LAB,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,PAYLOAD PROJECTS OFF,HUNTSVILLE,AL 35812. UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. FLORIDA INST TECHNOL,DEPT PHYS & SPACE SCI,MELBOURNE,FL 32901. RP MELENDEZALVIRA, DJ (reprint author), USN,RES LAB,EO HULBURT CTR SPACE RES,CODE 76431,4555 OVERLOOK AVE SW,WASHINGTON,DC 20375, USA. NR 70 TC 5 Z9 6 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 MAY 1 PY 1995 VL 100 IS A5 BP 7839 EP 7853 DI 10.1029/94JA02487 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY981 UT WOS:A1995QY98100023 ER PT J AU HAMMOND, CM FELDMAN, WC PHILLIPS, JL GOLDSTEIN, BE BALOGH, A AF HAMMOND, CM FELDMAN, WC PHILLIPS, JL GOLDSTEIN, BE BALOGH, A TI SOLAR-WIND DOUBLE ION-BEAMS AND THE HELIOSPHERIC CURRENT SHEET SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID COULOMB COLLISIONS; MAGNETOPAUSE AB Double ion beams are often observed in the solar wind, but little work has been done in relating these beams to structures within the solar wind. Double ion beams are observed as beams of a given ion species and charge state occurring at two different energies. We use the three-dimensional ion plasma instrument on board the Ulysses spacecraft to look for evidence of such beams associated with the heliospheric current sheet. In a subset chosen independently of plasma parameters consisting of 8 of over 47 crossings of the current sheet made during the in-ecliptic phase of the Ulysses mission we find that these double ion beams are always present on either side of the current sheet. The double beams are present in both the proton and helium species. The secondary beam typically has a higher helium abundance, which suggests that these beams are formed in the helium-rich corona rather than in interplanetary space. The double beams are not present in the interior of the current sheet. Neither collisions nor effects of plasma beta can account for the disappearance of the double beams inside the current sheet iri all eight cases. We postulate that these beams are formed by reconnection occurring near the Sun in the boundary region between the open field lines of the coronal holes and the closed field line region of the heliospheric current sheet. Such a scenario would be consistent with previous X ray measurements which suggest that reconnection is occurring in this region. C1 UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,BLACKETT LAB,LONDON SW7 2BZ,ENGLAND. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP HAMMOND, CM (reprint author), LOS ALAMOS NATL LAB,MAIL STOP D466,LOS ALAMOS,NM 87545, USA. NR 21 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1995 VL 100 IS A5 BP 7881 EP 7889 DI 10.1029/94JA03304 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY981 UT WOS:A1995QY98100029 ER PT J AU PEREDO, M SLAVIN, JA MAZUR, E CURTIS, SA AF PEREDO, M SLAVIN, JA MAZUR, E CURTIS, SA TI 3-DIMENSIONAL POSITION AND SHAPE OF THE BOW SHOCK AND THEIR VARIATION WITH ALFVENIC, SONIC AND MAGNETOSONIC MACH NUMBERS AND INTERPLANETARY MAGNETIC-FIELD ORIENTATION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND INTERACTION; TERRESTRIAL PLANETS; MAGNETOPAUSE SHAPE; MAGNETOSHEATH; LOCATIONS; FLOW AB A large set of bow shock crossings (i.e., 1392) observed by 17 spacecraft has been used to explore the three-dimensional shape and location of the Earth's bow shock and its dependence on solar wind and interplanetary magnetic field (IMF) conditions. This study: investigates deviations from gas dynamic flow models associated with the magnetic terms in the magnetohydrodynamic (MHD) equations. Empirical models predicting the statistical position and shape of the bow shock for arbitrary values of the solar wind pressure, IMF, and Alfvenic Mach number (M(A)) have been derived. Individual crossings have been rotated into aberrated GSE coordinates to remove asymmetries associated with the earth's orbital motion. Variations due to changes in solar wind dynamic pressure have been taken into consideration by normalizing the observed crossings to the average value [p] = 3.1 nPa. The resulting data set has been used to fit three-dimensional bow shock surfaces and to explore the variations in these surfaces with sonic (M(S)), Alfvenic (M(A)) and magnetosonic (M(MS)) Mach numbers. Analysis reveals that among the three Mach numbers, M(A) provides the best ordering of the least square bow shock curves. The subsolar shock is observed to move Earthward while the flanks flare outward in response to decreasing M(A); the net change represents a 6-10% effect. Variations due to changes in the IMF orientation were investigated by rotating the crossings into geocentric interplanetary medium coordinates. Past studies have suggested that the north-south extent of the bow shock surface exceeds the east-west dimension due to asymmetries in the fast mode Mach cone. This study confirms such a north-south versus east-west asymmetry and quantifies its variation with M(S), M(A), M(MS), and IMF orientation. A 2-7% effect is measured, with the asymmetry being more pronounced at low Mach numbers. Combining the bow shock models with the magnetopause model of Roelof and Sibeck (1993), variations in the magnetosheath thickness at different local times are explored. The ratio of the bow shock size to the magnetopause size at the subsolar point is found to be 1.46; at dawn and dusk, the ratios are found to be 1.89 and 1.93, respectively. The subsolar magnetosheath thickness is used to derive the polytropic index gamma according to the empirical relation of Spreiter et al. (1966). The resulting gamma = 2.3 suggests the empirical formula is inadequate to describe the MHD interaction between the solar wind and the magnetosphere. RP PEREDO, M (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 695,GREENBELT,MD 20771, USA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 55 TC 160 Z9 162 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1995 VL 100 IS A5 BP 7907 EP 7916 DI 10.1029/94JA02545 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY981 UT WOS:A1995QY98100032 ER PT J AU GUITER, SM RASMUSSEN, CE GOMBOSI, TI SOJKA, JJ SCHUNK, RW AF GUITER, SM RASMUSSEN, CE GOMBOSI, TI SOJKA, JJ SCHUNK, RW TI WHAT IS THE SOURCE OF OBSERVED ANNUAL VARIATIONS IN PLASMASPHERIC DENSITY SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-DENSITY; MASS-SPECTROMETER; SEASONAL BEHAVIOR; IONOSPHERE; MODEL; WHISTLERS; FLUX AB Plasmaspheric densities have been observed previously to be higher in December than in June, with the ratio varying between 1.5 and 3.0 and with larger variations at lower L shells. In order to search for the cause of the observed annual variations, we have modeled plasmaspheric density, using a time-dependent hydrodynamic model. On an L = 2 field line with geomagnetic longitude equal to 300 degrees, the modeled plasmaspheric densities were a factor of 1.5 times higher in December than in June. The modeled December to June density ratio was found to increase slightly with L shell, in contrast to observations; this discrepancy may be due to the fact that outer plasmaspheric flux tubes are never completely full. In addition, for an L = 2 field line with geomagnetic longitude equal to 120 degrees, the modeled plasmaspheric density was higher in June than in December by a factor of about 1.2. Various numerical tests were also performed in order to examine the sensitivity of plasmaspheric density to various parameters. In particular, a large vertical neutral wind was applied in order to raise the O+ profile, which had the effect of raising plasmaspheric density by a factor of 6. This in conjunction with a theoretical analysis suggests that plasmaspheric density levels are very sensitive to O+ levels in the upper ionosphere. We conclude that annual variations in plasmaspheric density are due to similar variations in ionospheric O+. C1 UNIV MICHIGAN,SPACE PHYS RES LAB,ANN ARBOR,MI 48109. UTAH STATE UNIV,CTR ATMOSPHER & SPACE SCI,LOGAN,UT 84322. RP GUITER, SM (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. RI Gombosi, Tamas/G-4238-2011 OI Gombosi, Tamas/0000-0001-9360-4951 NR 21 TC 13 Z9 13 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1995 VL 100 IS A5 BP 8013 EP 8020 DI 10.1029/94JA02866 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY981 UT WOS:A1995QY98100041 ER PT J AU EVANS, SW DUKEMAN, GA AF EVANS, SW DUKEMAN, GA TI EXAMINATION OF A PRACTICAL AEROBRAKING GUIDANCE ALGORITHM SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID AEROASSISTED ORBITAL TRANSFER; OPTIMAL TRAJECTORIES AB A practical real time guidance algorithm has been developed for aerobraking vehicles that minimizes the post-aeropass Delta V requirement for orbit insertion while nearly minimizing the maximum heating rate and the maximum structural loads. The algorithm is general in the sense that a minimum of assumptions is made, thus greatly reducing the number of parameters that must be determined prior to a given mission. An interesting feature is that in-plane guidance performance is tuned by adjusting one mission dependent parameter, the bank margin; similarly, the out-of-plane guidance performance is tuned by adjusting a plane controller time constant. Other features of the algorithm are simplicity, efficiency, and case of use. The algorithm is designed for, but not necessary restricted to, a trimmed vehicle with bank angle modulation as the method of trajectory control. Performance of this guidance algorithm during flight in Earth's atmosphere is examined by its use in an aerobraking testbed program. The performance inquiry extends to a wide range of entry speeds covering a number of potential mission applications. Favorable results have been obtained with a minimum of development effort, and directions for improvement of performance are indicated. RP EVANS, SW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,FLIGHT MECH BRANCH,HUNTSVILLE,AL 35812, USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1995 VL 18 IS 3 BP 471 EP 477 DI 10.2514/3.21411 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA QY606 UT WOS:A1995QY60600012 ER PT J AU ARDEMA, MD BOWLES, JV TERJESEN, EJ WHITTAKER, T AF ARDEMA, MD BOWLES, JV TERJESEN, EJ WHITTAKER, T TI APPROXIMATE ALTITUDE TRANSITIONS FOR HIGH-SPEED AIRCRAFT SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB In a previous paper, a near optimal guidance law for the ascent trajectory from Earth surface to Earth orbit of a hypersonic, dual-mode propulsion, lifting vehicle was derived. The energy-state approximation was used to determine the near-optimal flight path and the operation of the propulsion system. In this paper, the problem of the instantaneous attitude transitions that occur in energy-state approximation is addressed. The approach is to model the transitions as a sequence of two load factor-bounded paths (either climb-dive of dive-climb). The precise location of the transition is determined from analysis of the boundary layer equations associated with the energy-state dynamic model. C1 NASA,AMES RES CTR,SYST ANAL BRANCH,MOFFETT FIELD,CA 94035. STERLING SOFTWARE INC,COMPUTAT SCI,MOFFETT FIELD,CA 94035. RP ARDEMA, MD (reprint author), SANTA CLARA UNIV,DEPT MECH ENGN,SANTA CLARA,CA 95053, USA. NR 15 TC 8 Z9 8 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1995 VL 18 IS 3 BP 561 EP 566 DI 10.2514/3.21423 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA QY606 UT WOS:A1995QY60600024 ER PT J AU WIE, B LIU, QA SUNKEL, J AF WIE, B LIU, QA SUNKEL, J TI ROBUST STABILIZATION OF THE SPACE STATION IN THE PRESENCE OF INERTIA MATRIX UNCERTAINTY SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID MOMENTUM MANAGEMENT; ATTITUDE-CONTROL; DESIGN AB The robust stabilization problem of the space station in the face of inertia matrix uncertainty is formulated as a robust H-infinity full-state feedback control problem with direct coupling between the controlled output and disturbance input. The control design objective is to yield the largest stable hypercube in uncertain parameter space, while satisfying the nominal performance requirements. The significance of employing an uncertain plant model with direct coupling between the controlled output and disturbance input is demonstrated. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV CONTROL & AERONAUT,HOUSTON,TX 77058. RP WIE, B (reprint author), ARIZONA STATE UNIV,DEPT MECH & AEROSP ENGN,TEMPE,AZ 85287, USA. NR 16 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 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAY-JUN PY 1995 VL 18 IS 3 BP 611 EP 617 DI 10.2514/3.21431 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA QY606 UT WOS:A1995QY60600032 ER PT J AU LITT, J KURTKAYA, M DUYAR, A AF LITT, J KURTKAYA, M DUYAR, A TI SENSOR FAULT-DETECTION AND DIAGNOSIS FOR A T700 TURBOSHAFT ENGINE SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Note C1 OYAK RENAULT AUTOMOBILE CO,RES & DEV,BURSA,TURKEY. FLORIDA ATLANTIC UNIV,DEPT MECH ENGN,BOCA RATON,FL 33431. RP LITT, J (reprint author), NASA,LEWIS RES CTR,VEHICLE PROP DIRECTORATE,ARMY RES LAB,MAIL STOP 77-1,2100 BROOKPARK RD,CLEVELAND,OH 44135, USA. NR 5 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 MAY-JUN PY 1995 VL 18 IS 3 BP 640 EP 642 DI 10.2514/3.21439 PG 3 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA QY606 UT WOS:A1995QY60600040 ER PT J AU SARAVANOS, DA HEYLIGER, PR AF SARAVANOS, DA HEYLIGER, PR TI COUPLED LAYERWISE ANALYSIS OF COMPOSITE BEAMS WITH EMBEDDED PIEZOELECTRIC SENSORS AND ACTUATORS SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article ID ELEMENT; PLATES; DESIGN AB Unified mechanics are developed with the capability to model both sensory and active composite laminates with embedded piezoelectric layers. Two discrete-layer (or layerwise) formulations enable analysis of both global and local electromechanical response. The first assumes constant through-the-thickness displacement, while the second permits piecewise continuous variation. The mechanics include the contributions from elastic, piezoelectric and dielectric components. The incorporation of electric potential into the state variables permits representation of general electromechanical boundary conditions. Approximate finite element solutions for the static and free-vibration analysis of beams are presented. Applications on composite beams demonstrate the capability to represent either sensory or active structures, and to model the complicated stress-strain fields, the interactions between passive/active layers and interfacial phenomena between sensors and composite plies. The capability to predict the dynamic characteristics under various electrical boundary conditions is demonstrated. Some advantages of the variable transverse displacement formulation on the free-vibration response of sensory structures are also shown. C1 COLORADO STATE UNIV,DEPT CIVIL ENGN,FT COLLINS,CO 80523. RP SARAVANOS, DA (reprint author), NASA,LEWIS RES CTR,STRUCT MECH BRANCH,21000 BROOKPARK RD,MS 49-8,CLEVELAND,OH 44135, USA. NR 25 TC 159 Z9 164 U1 1 U2 16 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD MAY PY 1995 VL 6 IS 3 BP 350 EP 363 PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA RD585 UT WOS:A1995RD58500006 ER PT J AU CHEN, XF JOHNSON, DR NOEBE, RD OLIVER, BF AF CHEN, XF JOHNSON, DR NOEBE, RD OLIVER, BF TI DEFORMATION AND FRACTURE OF A DIRECTIONALLY SOLIDIFIED NIAL-28CR-6MO EUTECTIC ALLOY SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ROD-PLATE TRANSITION; INTERMETALLIC ALLOYS; SINGLE-CRYSTALS; PHASE AB A directionally solidified alloy based on the NiAl-(Cr, Mo) eutectic was examined by transmission and scanning electron microscopy to characterize the microstructure and room temperature deformation and fracture behavior. The microstructure consisted of a lamellar morphology with a [111] growth direction for both the NiAl and (Cr, Mo) phases, The interphase boundary between the eutectic phases was semicoherent and composed of a well-defined dislocation network. In addition, a fine array of coherent NiAl precipitates was dispersed throughout the (Cr, Mo) phase, The eutectic morphology was stable at 1300 K with only coarsening of the NiAl precipitates occurring after heat treatment for 1.8 ks (500 h). Fracture of the aligned eutectic is characterized primarily by a crack bridging/renucleation mechanism and is controlled by the strength of the semicoherent interface between the two phases. However, contributions to the toughness of the eutectic may arise from plastic deformation of the NiAl phase and the geometry associated with the fracture process. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996. RP CHEN, XF (reprint author), UNIV TENNESSEE,DEPT MAT SCI & ENGN,KNOXVILLE,TN 37996, USA. NR 19 TC 78 Z9 88 U1 1 U2 3 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 MAY PY 1995 VL 10 IS 5 BP 1159 EP 1170 DI 10.1557/JMR.1995.1159 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA QU865 UT WOS:A1995QU86500015 ER PT J AU WHITTENBERGER, JD LUTON, MJ AF WHITTENBERGER, JD LUTON, MJ TI ELEVATED-TEMPERATURE CREEP-PROPERTIES OF NIAL CRYOMILLED WITH AND WITHOUT Y2O3 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID COMPRESSIVE PROPERTIES; ALN COMPOSITE AB The creep properties of lots of NiAl cryomilled with and without Y2O3 have been determined in compression and tension. Although identical cryomilling procedures were used, differences in composition were found between the lot ground with 0.5 vol % yttria and the lot ground without Y2O3. Compression testing between 1000 and 1300 K yielded similar creep strengths for both materials, while tensile creep rupture testing indicated that the yttria-containing alloy was slightly stronger than the Y2O3-free version. Both compression and tensile testing showed two deformation regimes; whereas the stress state did not affect the high stress exponent (n approximate to 10) mechanism, the low stress exponent regime n was similar to 6 in tension and similar to 2 in compression. The strengths in tension were somewhat less than those measured in compression, but the estimated activation energies (Q) of similar to 600 kJ/mol for tensile testing were closer to the previously measured values (similar to 700 kJ/mol) for NiAl-AlN and very different from the Q's of 400 and 200 kJ/mol for compression tests in the high and low stress exponent regimes, respectively. A Larson-Miller comparison indicated that cyromilling can produce an alloy with long-term, high-temperature strength at least equal to conventional superalloys. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. EXXON RES & ENGN CO,ANNANDALE,NJ 08801. NR 21 TC 16 Z9 16 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 MAY PY 1995 VL 10 IS 5 BP 1171 EP 1186 DI 10.1557/JMR.1995.1171 PG 16 WC Materials Science, Multidisciplinary SC Materials Science GA QU865 UT WOS:A1995QU86500016 ER PT J AU PIERSON, DL MEHTA, SK MAGEE, BB MISHRA, SK AF PIERSON, DL MEHTA, SK MAGEE, BB MISHRA, SK TI PERSON-TO-PERSON TRANSFER OF CANDIDA-ALBICANS IN THE SPACECRAFT ENVIRONMENT SO JOURNAL OF MEDICAL AND VETERINARY MYCOLOGY LA English DT Article ID FRAGMENT-LENGTH-POLYMORPHISMS; DURATION MISSIONS; IMMUNE CHANGES; TYPING METHODS; STRAINS; WOMEN AB We assessed the exchange of Candida albicans among crew members during 10 Space Shuttle missions. Throat, nasal, urine and faecal specimens were collected from 61 crew members twice before and once after space flights ranging from 7 to 10 days in duration; crews consisted of groups of five, six or seven men and women. Candida albicans was isolated at least once from 20 of the 61 subjects (33%). Candida strains were identified by restriction-fragment length polymorphism (RFLP) after digestion by the endonucleases EcoRI and HinfI; further discrimination was gained by Southern blot hybridization with the C. albicans repeat fragment 27A. Eighteen of the 20 Candida-positive crew members carried different strains of C. albicans in the specimens collected. Possible transfer of C. albicans between members of the same crew was demonstrated only once in the 10 missions studied. We conclude that the transfer of C. albicans among crew members during Space Shuttle flights is less frequent than had been predicted from earlier reports. C1 NASA,LYNDON B JOHNSON SPACE CTR,KRUG LIFE SCI,HOUSTON,TX 77058. UNIV MINNESOTA,COLL BIOL SCI,DEPT GENET & CELL BIOL,ST PAUL,MN. RP PIERSON, DL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,MAIL CODE SD4,HOUSTON,TX 77058, USA. NR 22 TC 13 Z9 14 U1 1 U2 3 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0268-1218 J9 J MED VET MYCOL JI J. Med. Vet. Mycol. PD MAY-JUN PY 1995 VL 33 IS 3 BP 145 EP 150 PG 6 WC Mycology SC Mycology GA RD735 UT WOS:A1995RD73500001 PM 7666293 ER PT J AU LEVY, RJ FEEBACK, DL BRUMBACK, RA AF LEVY, RJ FEEBACK, DL BRUMBACK, RA TI COMBINATION STAIN FOR DEMONSTRATION OF MUSCLE-FIBER TYPE AND CAPILLARY MORPHOLOGY IN HUMAN SKELETAL-MUSCLE BIOPSY SECTIONS SO JOURNAL OF NEUROPATHOLOGY AND EXPERIMENTAL NEUROLOGY LA English DT Meeting Abstract C1 KRUG LIFE SCI,HOUSTON,TX. NASA,HOUSTON,TX. UNIV OKLAHOMA,HLTH SCI CTR,OKLAHOMA CITY,OK. RI Brumback, Roger/A-2404-2008 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSN NEUROPATHOLOGISTS INC PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 SN 0022-3069 J9 J NEUROPATH EXP NEUR JI J. Neuropathol. Exp. Neurol. PD MAY PY 1995 VL 54 IS 3 BP 452 EP 452 DI 10.1097/00005072-199505000-00179 PG 1 WC Clinical Neurology; Neurosciences; Pathology SC Neurosciences & Neurology; Pathology GA QX385 UT WOS:A1995QX38500178 ER PT J AU WHARTON, RA CROSBY, JM MCKAY, CP RICE, JW AF WHARTON, RA CROSBY, JM MCKAY, CP RICE, JW TI PALEOLAKES ON MARS SO JOURNAL OF PALEOLIMNOLOGY LA English DT Article DE MARS; MARTIAN PALEOLAKES; LACUSTRINE SEDIMENTS; ICE-COVERED LAKES ID MARTIAN CHANNELS; CLIMATIC-CHANGE; PLANETARY-ATMOSPHERES; VALLES MARINERIS; LIQUID WATER; LAKE HOARE; ORIGIN; ICE; EVOLUTION; SEDIMENTATION AB Observational evidence such as outflow channels and valley networks suggest that in the past there was flowing water on Mars. The images of fluvial features on Mars logically suggest that there must exist downstream locations in which the water pooled and the sediment load deposited (i.e. lakes). Sediments and morphological features associated with the martian paleolakes are believed to occur in Valles Marineris, and several large basins including Amazonis, Chryse and Elysium planitia. As Mars became progressively colder over geological time, any lakes on its surface would have become seasonally, and eventually perennially ice-covered. We know from polar lakes on Earth that ice-covered lakes can persist even when the mean annual temperature falls below freezing. Thus, the most recent lacustrine sediments on Mars were probably deposited in ice-covered lakes. While life outside of the Earth's atmosphere has yet to be observed, there is a general consensus among exobiologists that the search for extraterrestrial life should be based upon liquid water. The inference that there was liquid water on Mars during an earlier epoch is the primary motivation for considering the possibility of life during this time. It would be of enormous interest from both an exobiological and paleolimnological perspective to discover lakes or the evidence of former lakes on another planet such as Mars. Limnology would then become an interplanetary science. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. ARIZONA STATE UNIV,DEPT GEOG,TEMPE,AZ 85287. RP WHARTON, RA (reprint author), UNIV NEVADA,DESERT RES INST,POB 60220,RENO,NV 89506, USA. FU NCI NIH HHS [NCA2-799] NR 79 TC 25 Z9 25 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0921-2728 J9 J PALEOLIMNOL JI J. Paleolimn. PD MAY PY 1995 VL 13 IS 3 BP 267 EP 283 DI 10.1007/BF00682769 PG 17 WC Environmental Sciences; Geosciences, Multidisciplinary; Limnology SC Environmental Sciences & Ecology; Geology; Marine & Freshwater Biology GA RP373 UT WOS:A1995RP37300006 PM 11539841 ER PT J AU HATCH, MS SOWA, WA SAMUELSEN, GS HOLDEMAN, JD AF HATCH, MS SOWA, WA SAMUELSEN, GS HOLDEMAN, JD TI GEOMETRY AND FLOW INFLUENCES ON JET MIXING IN A CYLINDRICAL DUCT SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID CROSS-FLOW AB To examine the mixing characteristics of jets in an axisymmetric can geometry, temperature measurements were obtained downstream of a row of cold jets injected into a heated cross stream. Parametric, nonreacting experiments were conducted to determine the influence of geometry and flow variations on mixing patterns in a cylindrical configuration, Results show that jet-to-mainstream momentum-nux ratio and orifice geometry significantly impact the mixing characteristics of jets in a can geometry. For a fixed number of orifices, the coupling between momentum-flux ratio and injector geometry determines 1) the degree of jet penetration at the injection plane and 2) the extent of circumferential mixing downstream of the injection plane. The results also show that, at a fixed momentum-flux ratio, jet penetration decreases with 1) an increase in slanted slot aspect ratio and 2) an increase in the angle of the slots with respect to the mainstream direction. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP HATCH, MS (reprint author), UNIV CALIF IRVINE,COMBUST LAB,IRVINE,CA 92717, USA. NR 18 TC 18 Z9 20 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1995 VL 11 IS 3 BP 393 EP 402 DI 10.2514/3.23857 PG 10 WC Engineering, Aerospace SC Engineering GA QZ089 UT WOS:A1995QZ08900001 ER PT J AU RIGGINS, DW MCCLINTON, CR ROGERS, RC BITTNER, RD AF RIGGINS, DW MCCLINTON, CR ROGERS, RC BITTNER, RD TI INVESTIGATION OF SCRAMJET INJECTION STRATEGIES FOR HIGH MACH NUMBER FLOWS SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB A method for estimating the axial distribution of thrust performance potential in a supersonic combustor is described, A complementary technique for illustrating the spatial evolution and distribution of thrust potential and loss mechanisms in reacting flows is developed. A wall jet case and swept ramp injector case for Mach 17 and Mach 13.5 flight enthalpy inflow conditions, respectively, are numerically modeled and analyzed using these techniques. C1 NASA,LANGLEY RES CTR,NUMER APPLICAT OFF,HAMPTON,VA 23681. ANALYT SERV & MAT INC,HYPERSON PROPULS BRANCH,HAMPTON,VA 23681. RP RIGGINS, DW (reprint author), UNIV MISSOURI,DEPT MECH & AEROSP ENGN,ROLLA,MO 65401, USA. NR 17 TC 27 Z9 29 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1995 VL 11 IS 3 BP 409 EP 418 DI 10.2514/3.23859 PG 10 WC Engineering, Aerospace SC Engineering GA QZ089 UT WOS:A1995QZ08900003 ER PT J AU LIN, TY BAKER, D AF LIN, TY BAKER, D TI ANALYSIS AND TESTING OF PROPELLANT FEED SYSTEM PRIMING PROCESS SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB This article presents analytical and experimental results on the priming of a propellant feed system with initial line pressures of 0 psia and greater. The analysis employs the method of characteristics to treat one-dimensional liquid transients in liquid-full segments, and the lumped-inertia technique to model the dynamics of partially filled (or two-phase) segments. Fluid compressibility and piping flexibility are accounted for, and the method of characteristics can undertake a complex system. The highly significant correlation obtained between predictions and test results verifies that the methods are suitable for analyzing a complicated network system. C1 NASA,JOHNSON SPACE FLIGHT CTR,LAB OFF,WHITE SANDS TEST FACIL,LAS CRUCES,NM 88004. RP LIN, TY (reprint author), MCDONNELL DOUGLAS CORP,AEROSP,DIV SPACE STN,HUNTINGTON BEACH,CA 92647, USA. NR 8 TC 5 Z9 12 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1995 VL 11 IS 3 BP 505 EP 512 DI 10.2514/3.23871 PG 8 WC Engineering, Aerospace SC Engineering GA QZ089 UT WOS:A1995QZ08900015 ER PT J AU APPELBAUM, J SHERMAN, I LANDIS, GA AF APPELBAUM, J SHERMAN, I LANDIS, GA TI SOLAR-RADIATION ON MARS - STATIONARY PHOTOVOLTAIC ARRAY SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID POWER AB Solar energy is an important power source for surface-based operation on Mars. Photovoltaic cells offer many advantages. Detailed information on solar radiation characteristics on Mars are necessary for effective design of future planned photovoltaic systems. In this article we present analytical expressions for solar radiation calculation and solar radiation data for inclined stationary nat surfaces for Mars as functions of day, latitude, and atmospheric dust load (optical depth). The diffuse component of the solar radiation on Mars due to the atmospheric dust can be significant, thus greatly affecting the optimal inclination angle of the photovoltaic array. The yearly optimal inclination angle for atmospheric optical depths measured by the Viking landers resulted in much smaller angles than the local latitudes. C1 TEL AVIV UNIV,FAC ENGN,IL-69978 RAMAT AVIV,ISRAEL. WJ SCHAFFER ASSOCIATES,BROOKPARK,OH 44142. RP APPELBAUM, J (reprint author), NASA,LEWIS RES CTR,NATL RES COUNCIL,CLEVELAND,OH 44135, USA. NR 9 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAY-JUN PY 1995 VL 11 IS 3 BP 554 EP 561 DI 10.2514/3.23877 PG 8 WC Engineering, Aerospace SC Engineering GA QZ089 UT WOS:A1995QZ08900021 ER PT J AU KRATZ, DP AF KRATZ, DP TI THE CORRELATED KAPPA-DISTRIBUTION TECHNIQUE AS APPLIED TO THE AVHRR CHANNELS SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID WATER-VAPOR BANDS; SOLAR-RADIATION; K-DISTRIBUTION; COOLING RATES; NONHOMOGENEOUS ATMOSPHERES; TRANSMISSION FUNCTIONS; CONTINUUM ABSORPTION; CLIMATE MODELS; CO2; PARAMETERIZATIONS AB Correlated k-distributions have been created to account for the molecular absorption found in the spectral ranges of the five Advanced Very High Resolution Radiometer (AVHRR) satellite channels. The production of the k-distributions was based upon an exponential-sum fitting of transmissions (ESFT) technique which was applied to reference line-by-line absorptance calculations. To account for the overlap of spectral features from different molecular species, the present routines made use of the multiplication transmissivity property which allows for considerable flexibility, especially when altering relative mixing ratios of the various molecular species. To determine the accuracy of the correlated k-distribution technique as compared to the line-by-line procedure, atmospheric flux and heating rate calculations were run for a wide variety of atmospheric conditions. For the atmospheric conditions taken into consideration, the correlated k-distribution technique has yielded results within about 0.5% for both the cases where the satellite spectral response functions were applied and where they were not. The correlated k-distribution's principal advantage is that it can be incorporated directly into multiple scattering routines that consider scattering as well as absorption by clouds and aerosol particles. RP KRATZ, DP (reprint author), NASA,LANGLEY RES CTR,DIV ATMOSPHER SCI,HAMPTON,VA 23681, USA. NR 60 TC 84 Z9 84 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAY PY 1995 VL 53 IS 5 BP 501 EP 517 DI 10.1016/0022-4073(95)00006-7 PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA RD791 UT WOS:A1995RD79100004 ER PT J AU RAULT, DFG WORONOWICZ, MS AF RAULT, DFG WORONOWICZ, MS TI APPLICATION OF DIRECT SIMULATION MONTE-CARLO TO SATELLITE CONTAMINATION STUDIES SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A novel method is presented to estimate contaminant levels around spacecraft and satellites of arbitrarily complex geometry. The method uses a three-dimensional direct simulation Monte Carlo algorithm to characterize the contaminant cloud surrounding the space platform, and a computer-assisted design preprocessor to define the space-platform geometry. The method is applied to the Upper Atmosphere Research Satellite to estimate the contaminant flux incident on the optics of the halogen occultation experiment (HALOE) telescope. Results are presented in terms of contaminant cloud structure, molecular velocity distribution at HALOE aperture, and code performance. C1 VIGYAN INC,HAMPTON,VA 23666. RP RAULT, DFG (reprint author), NASA,LANGLEY RES CTR,DIV GAS DYNAM,AEROTHERMODYNAM BRANCH,HAMPTON,VA 23681, USA. NR 15 TC 6 Z9 6 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 MAY-JUN PY 1995 VL 32 IS 3 BP 392 EP 397 DI 10.2514/3.26627 PG 6 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000002 ER PT J AU HAAS, BL MILOS, FS AF HAAS, BL MILOS, FS TI SIMULATED RAREFIED ENTRY OF THE GALILEO PROBE INTO THE JOVIAN ATMOSPHERE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID RELAXATION AB Flowfield properties and aerodynamics are computed with a direct simulation Monte Carlo method in the rarefied flow regime during entry of the Galileo Probe into the atmosphere of Jupiter. The objective is to predict accurately the vehicle's drag coefficient, which is needed to assess atmospheric properties from the onboard atmospheric structure experiment, where highly sensitive accelerometers will measure the drag effects to within 10(-5) m/s(2) during the initial entry phase at high altitudes. The corresponding flow rarefaction extends from the free-molecule limit to the near-continuum transition regime (Re-infinity < 1000). Simulation results, employing a simple radiative equilibrium surface model, indicate that C-D varies from 2.1 at the free-molecule limit down to 1.6 at Re-infinity = 1000. Results compared very well to those from ballistic-range experiments. Detailed material response of the carbon-phenolic heat shield was then coupled directly into the DSMC code to account accurately for conductivity, heat capacity, and pyrolysis, and the simulations were repeated. The predicted pyrolysis mass efflux was 8-14 times higher than the incident freestream mass flux and had significant effects on the drag. RP HAAS, BL (reprint author), NASA,AMES RES CTR,INST THERMOSCI,M-S 230-2,MOFFETT FIELD,CA 94035, USA. NR 33 TC 5 Z9 5 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 398 EP 403 DI 10.2514/3.26628 PG 6 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000003 ER PT J AU BRAUN, RD POWELL, RW LEPSCH, RA STANLEY, DO KROO, IM AF BRAUN, RD POWELL, RW LEPSCH, RA STANLEY, DO KROO, IM TI COMPARISON OF 2 MULTIDISCIPLINARY OPTIMIZATION STRATEGIES FOR LAUNCH-VEHICLE DESIGN SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB The investigation focuses on development of a rapid multidisciplinary analysis and optimization capability for launch-vehicle design. Two multidisciplinary optimization strategies in which the analyses are integrated in different manners are implemented and evaluated for solution of a single-stage-to-orbit launch-vehicle design problem. Weights and sizing, propulsion, and trajectory issues are directly addressed in each optimization process. Additionally, the need to maintain a consistent vehicle model across the disciplines is discussed. Both solution strategics were shown to obtain similar solutions from two different starting points. These solutions suggests that a dual-fuel, single-stage-to-orbit vehicle with a dry weight of approximately 1.927 x 10(5) lb, gross liftoff weight of 2.165 x 10(6) lb, and length of 181 ft is attainable. A comparison of the two approaches demonstrates that treatment of disciplinary coupling has a direct effect on optimization convergence and the required computational effort. In comparison with the first solution strategy, which is of the general form typically used within the launch vehicle design community at present, the second optimization approach is shown to be 3-4 times more computationally efficient. C1 STANFORD UNIV,DEPT AERONAUT & ASTRONAUT,STANFORD,CA 94305. RP BRAUN, RD (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST & CONCEPTS,HAMPTON,VA 23681, USA. NR 27 TC 23 Z9 24 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 MAY-JUN PY 1995 VL 32 IS 3 BP 404 EP 410 DI 10.2514/3.26629 PG 7 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000004 ER PT J AU LEPSCH, RA STANLEY, DO UNAL, R AF LEPSCH, RA STANLEY, DO UNAL, R TI DUAL-FUEL PROPULSION IN SINGLE-STAGE ADVANCED MANNED LAUNCH SYSTEM VEHICLE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID OPTIMIZATION AB As part of the United States Advanced Manned Launch System study to determine a follow-on, or complement, to the Space Shuttle, a reusable single-stage-to-orbit concept utilizing dual-fuel rocket propulsion has been examined. Several dual-fuel propulsion concepts were investigated, These include: a separate-engine concept combining Russian RD-170 kerosene-fueled engines with space shuttle main engine-derivative engines; the kerosene and hydrogen-fueled Russian RD-701 engine; and a dual-fuel, dual-expander engine. Analysis to determine vehicle weight and size characteristics was performed using conceptual-level design techniques. A response-surface methodology for multidisciplinary design was utilized to optimize the dual-fuel vehicles with respect to several important propulsion-system and vehicle design parameters in order to achieve minimum empty weight. The tools and methods employed in the analysis profess are also summarized. In comparison with a reference hydrogen-fueled single-stage vehicle, results showed that the dual-fuel vehicles were from 10 to 30% lower in empty weight for the same payload capability, with the dual-expander engine types showing the greatest potential. C1 OLD DOMINION UNIV,DEPT ENGN MANAGEMENT,NORFOLK,VA 23529. RP LEPSCH, RA (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST & CONCEPTS,HAMPTON,VA 23681, USA. NR 31 TC 13 Z9 14 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 MAY-JUN PY 1995 VL 32 IS 3 BP 417 EP 425 DI 10.2514/3.26631 PG 9 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000006 ER PT J AU WILLIAMS, SD CURRY, DM BOUSLOG, SA ROCHELLE, WC AF WILLIAMS, SD CURRY, DM BOUSLOG, SA ROCHELLE, WC TI THERMAL PROTECTION SYSTEM-DESIGN STUDIES FOR LUNAR CREW MODULE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB This paper present the results of a trade study to predict aeroheating and thermal protection system (TPS) requirements for manned entry vehicles returning to Earth from the moon. The objectives of tile study were to assess the effects of vehicle size and lunar return strategies on both the aerothermodynamic environment and the TPS design. The study guidelines were based on an Apollo Command Module (CM) configuration for scales of 1.0, 1.5, and 2.5. Lunar return strategies included direct entry and aerocapture followed by low Earth orbit entry. Convective heating was obtained by the boundary-layer integral matrix procedure code, and radiative heating was computed with the QRAD program. The AESOP-STAB code was used for TPS analysis for ablating materials, and the AESOP-THERM code was used for nonablating materials. Principal results indicated that there was an optimum size for minimum heating with the Apollo CM-shaped vehicles, although heating rates were not a strong function of vehicle size. Direct entry had significantly higher heating rates than aerocapture; however, aerocapture resulted in higher heat loads and TPS weight. The TPS weight factor (ratio of TPS weight to total vehicle weight) was 6-8% for all lunar return strategies using an Avco ablator on the forebody and FRCI-12/LI-900 on the aftbody, with the TPS weight being about 50% less than that of the original Apollo CM vehicle. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV STRUCT & MECH,THERMAL BRANCH,HOUSTON,TX 77058. LOCKHEED ENGN & SCI CO INC,DEPT NAVIGAT CONTROL & AERONAUT,HOUSTON,TX 77258. RP WILLIAMS, SD (reprint author), LOCKHEED ENGN & SCI CO INC,DEPT SOFTWARE SYST & THERMAL TEST,POB 58561,MAIL STOP B14,HOUSTON,TX 77258, USA. NR 13 TC 4 Z9 4 U1 1 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 456 EP 462 DI 10.2514/3.26637 PG 7 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000012 ER PT J AU RUSSELL, DJ BELKNAP, SB TAYLOR, JT CHANG, YC AF RUSSELL, DJ BELKNAP, SB TAYLOR, JT CHANG, YC TI NEW METHOD FOR SHUTTLE ORBITER THERMAL-ANALYSIS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB A new, simplified, approximate method of on-orbit transient thermal analysis of complex operational space vehicles in varying environmental conditions is described. When applied to the Space Shuttle Orbiter simulation, the standard deviation of error in results compared with flight data for over 50 missions is typically between 5 and 10 degrees F. The method requires first running detailed orbiter thermal mathematical models for a steady-state solution in a systematized variety of on-orbit Earth-sun orientations. These steady-state temperatures form a database that is loaded and permanently stored in a personal-computer-based program package. An exponential extrapolation method derived from a classical simplified energy balance and using empirically derived time constants is applied to convert from the steady-state temperature to the actual transient response. Now in use routinely for thermal analysis of the Space Shuttle Orbiter, the method has reduced the days of engineering manpower and hours of mainframe computer usage previously required to a simple, painless, and short session on a personal computer. The results, although approximate and sometimes limited in certain special situations, have been found generally to yield excellent agreement with flight data. C1 NASA,LYNDON B JOHNSON SPACE CTR,DIV STRUCT & MECH,THERMAL BRANCH,HOUSTON,TX 77058. RP RUSSELL, DJ (reprint author), ROCKWELL INT CORP,DIV SPACE SYST,THERMAL CONTROL SYST ANAL UNIT,TECH STAFF,HOUSTON,TX 77058, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 463 EP 468 DI 10.2514/3.26638 PG 6 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000013 ER PT J AU KOONTZ, SL LEGER, LJ RICKMAN, SL HAKES, CL BUI, DT HUNTON, DE CROSS, JB AF KOONTZ, SL LEGER, LJ RICKMAN, SL HAKES, CL BUI, DT HUNTON, DE CROSS, JB TI OXYGEN INTERACTIONS WITH MATERIALS .3. MISSION AND INDUCED ENVIRONMENTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID IRRADIANCE COMPARISON EXPERIMENT-1; SOLAR AB The Evaluation of Oxygen Interactions with Materials III (EOIM-III) flight experiment was developed to obtain benchmark atomic-oxygen-material reactivity data. The experiment was conducted during Space Shuttle mission 46, July 31 to August 7, 1992. Quantitative interpretation of the materials reactivity measurements requires a complete and accurate definition of the space environment exposure, including the thermal history of the payload, the solar ultraviolet exposure, the atomic-oxygen fluence, and any spacecraft outgassing and contamination effects. The thermal history of the payload was measured using 11 thermocouple sensors placed behind selected samples and on the EOIM-III payload structure. The solar ultraviolet exposure history of the EOIM-III payload was determined by analysis of the as-flown orbit and vehicle attitude combined with daily average solar ultraviolet and vacuum ultraviolet fluxes. The atomic-oxygen fluence was assessed in three ways. First, the O-atom fluence was calculated using a program that incorporates the MSIS-86 atmospheric model, the as-flown Space Shuttle trajectory, and solar activity parameters. Second, it was estimated directly from Kapton film erosion. Third, ambient O-atom measurements were made using the quadrupole mass spectrometer on the EOIM-III payload. As of this writing, our best estimate of the O-atom fluence is (2.3 +/- 0.3) X 10(20) atoms/cm(2). Finally, results of postflight surface analysis of selected samples by x-ray photoelectron spectroscopy indicate low levels of molecular contamination on the payload surface. C1 LOCKHEED ENGN & SCI CO INC,HOUSTON,TX 77058. USAF,PHILLIPS LAB,IONOSPHER PHYS BRANCH,BEDFORD,MA 01731. LOS ALAMOS NATL LAB,DIV PHYS CHEM,LOS ALAMOS,NM 87545. RP KOONTZ, SL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 19 TC 44 Z9 46 U1 1 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 475 EP 482 DI 10.2514/3.26640 PG 8 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000015 ER PT J AU KOONTZ, SL LEGER, LJ VISENTINE, JT HUNTON, DE CROSS, JB HAKES, CL AF KOONTZ, SL LEGER, LJ VISENTINE, JT HUNTON, DE CROSS, JB HAKES, CL TI EOIM-III MASS-SPECTROMETRY AND POLYMER CHEMISTRY - STS-46, JULY-AUGUST 1992 SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID ATOMIC OXYGEN; POLYIMIDE FILMS AB The Evaluation of Oxygen Interactions with Materials III space-flight experiment was developed to obtain benchmark atomic-oxygen reactivity data and wits conducted during Space Transportation System Mission 46. We present an overview of the flight experiment and the results of the Lyndon B. Johnson Space Center polymer chemistry and mass-spectrometer-carousel experiments. Mass-spectrometric measurements of gaseous products formed by O-atom reaction with C-13-labeled Kaptan(TM) revealed CO, CO2, H2O, NO, and NO2. By operating the mass spectrometer to detect naturally occurring ionospheric species, we characterized the ambient ionosphere at various times during the flight experiment and detected the gaseous reaction products formed when ambient ions interacted with the C-13 Kapton carousel sector, Direct comparison of the results of on-orbit O-atom exposures with those conducted in ground-based laboratory systems, which provide known O-atom fluences and translational energies, demonstrated the strong translational-energy dependence of O-atom reactions with a variety of polymers. A line-of-centers reactive scattering model was shown to provide a reasonably accurate description of the translational-energy dependence of polymer reactions with O atoms at high atom kinetic energies, and a Beckede-Ceyer model provided an accurate description of O-atom reactivity over a three-order-of-magnitude range in translational energy and a four-order-of-magnitude range in reaction efficiency. Postflight studies of the polymer samples by x-ray photoelectron spectroscopy and infrared spectroscopy demonstrate that O-atom attack is confined to the near-surface region of the sample, that is, within 50 to 100 Angstrom of the surface. C1 USAF,PHILLIPS LAB,IONOSPHER PHYS BRANCH,BEDFORD,MA 01731. LOS ALAMOS NATL LAB,DIV PHYS CHEM,LOS ALAMOS,NM 87545. LOCKHEED ENGN & SCI CO,HOUSTON,TX 77058. RP KOONTZ, SL (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 29 TC 56 Z9 59 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 483 EP 495 DI 10.2514/3.26641 PG 13 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000016 ER PT J AU CROSS, JB KOONTZ, SL HUNTON, DE AF CROSS, JB KOONTZ, SL HUNTON, DE TI FLIGHT MASS-SPECTROMETER CALIBRATION IN A HIGH-VELOCITY ATOMIC-OXYGEN BEAM SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article AB Calibration and characterization of the quadrupole mass-spectrometer component of the Evaluation of Oxygen Interactions with Materials III space-flight experiment are reported in this paper. A high-velocity atom beam system was used to characterize the response of the flight mass spectrometer to high-velocity oxygen atoms (0.8 to 2.5 eV). The response factor based on oxygen atom flux in the high-velocity beam was found to be logarithmically dependent on the exposure history of the instrument, i.e., the calibration factor was logarithmically dependent on atomic oxygen fluence. This dependence was independent of the background pressure over the range between 10(-6) and 10(-4) Torr. Subsequent contamination of the instrument restored the instrument sensitivity to the original value before exposure to atomic oxygen. Carbon dioxide, carbon monoxide, and water were observed in the mass spectrometer whenever high-velocity oxygen atoms were present. The intensity of reaction products caused by interaction of atomic oxygen with contaminated surfaces within the instrument decreases with increasing atomic oxygen fluence, whereas O-2 resulting from recombination of atomic oxygen on surfaces increases with fluence. C1 NASA,JOHNSON SPACE FLIGHT CTR,HOUSTON,TX 77058. USAF,PHILLIPS LAB,BEDFORD,MA 01713. RP CROSS, JB (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 17 TC 19 Z9 19 U1 2 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 496 EP 501 DI 10.2514/3.26642 PG 6 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000017 ER PT J AU AHMADJIAN, M JENNINGS, DE AF AHMADJIAN, M JENNINGS, DE TI ANALYSIS OF STS-39 SPACE-SHUTTLE GLOW MEASUREMENTS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID VEHICLE GLOW; SATELLITE AB Measurements of Space Shuttle glow were conducted on STS-39. Cargo-bay infrared and visible sensors measured intensities and spectral distributions of shuttle glow as a function of attitude, gas releases, day/night, and mission elapsed time, One of these sensors, the spacecraft Kinetic Infrared Test (SKIRT), was a cryogenic infrared spectrometer (0.6-5.4 mu m) which observed nitric oxide, ionized nitric oxide, and hydroxyl in the quiescent and thruster-enhanced Shuttle glow, A nitric oxide gas release significantly enhanced the glow and showed a fast gas-phase reaction and a slower surface-mediated reaction, The glow was also shown to be dependent on the orientation of the shuttle, The change in glow intensity from pointing the orbiter and sensor along the velocity vector, into ram, versus looking 90 deg from ram, showed a cos(2) theta dependence, During nonglow quiescent times, when SKIRT was pointed away from ram toward deep space, there were no emissions down to the sensor noise level of 10(-10) W/cm(2) sr mu m. These measurements provided the first infrared measurements with sufficient sensitivity and spectral resolution to identify molecular species associated with Space Shuttle glow SKIRT demonstrated that very sensitive cryogenic infrared sensors can operate from the Space Shuttle cargo bay. C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RP AHMADJIAN, M (reprint author), USAF,HQ SPACE & MISSILES CTR,PHILLIPS LAB GEOPHYS DIRECTORATE,29 RANDOLPH RD,BEDFORD,MA 01731, USA. RI Jennings, Donald/D-7978-2012 NR 14 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 MAY-JUN PY 1995 VL 32 IS 3 BP 507 EP 513 DI 10.2514/3.26644 PG 7 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000019 ER PT J AU SUSKO, M HERMAN, L AF SUSKO, M HERMAN, L TI COMPARISON OF SATELLITE-DERIVED WIND MEASUREMENTS WITH OTHER WIND MEASUREMENT SENSORS SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NOAA,MADISON,WI 53906. NATL ENVIRONM SATELLITE DATA & INFORMAT SERV,MADISON,WI 53906. RP SUSKO, M (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,EARTH SYST OBSERV BRANCH,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAY-JUN PY 1995 VL 32 IS 3 BP 564 EP 566 DI 10.2514/3.26653 PG 3 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000028 ER PT J AU QUEEN, E THOMPSON, A AF QUEEN, E THOMPSON, A TI EFFECT OF PAYLOAD ON RISK OF VEHICLE LOSS DUE TO ENGINE FAILURE SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Note C1 NASA,LANGLEY RES CTR,DIV AERONAUT SYST ANAL,SYST ANAL BRANCH,HAMPTON,VA 23681. RP QUEEN, E (reprint author), NASA,LANGLEY RES CTR,DIV SPACE SYST CONCEPTS,VEHICLE ANAL BRANCH,HAMPTON,VA 23681, 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 MAY-JUN PY 1995 VL 32 IS 3 BP 566 EP 568 DI 10.2514/3.26654 PG 3 WC Engineering, Aerospace SC Engineering GA RC460 UT WOS:A1995RC46000029 ER PT J AU DANCHAIVIJIT, S SHETTY, DK ELDRIDGE, J AF DANCHAIVIJIT, S SHETTY, DK ELDRIDGE, J TI CRITICAL STRESSES FOR EXTENSION OF FILAMENT-BRIDGED MATRIX CRACKS IN CERAMIC-MATRIX COMPOSITES - AN ASSESSMENT WITH A MODEL COMPOSITE WITH TAILORED INTERFACES SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID FIBER-REINFORCED CERAMICS; MECHANICS; FRACTURE AB Matrix cracking was studied in a model unidirectional composite of SiC filaments in an epoxy-bonded alumina matrix, The residual clamping stress on the filaments due to the shrinkage of the epoxy was moderated with the addition of the alumina filler, and the filament surface was coated with a releasing agent to produce unbonded frictional interfaces. Uniaxial tension specimens with controlled through-cracks with bridging filaments were fabricated by a two-step casting technique, Critical stresses for extension of the filament-bridged cracks of various lengths were measured in uniaxial tension using a high-sensitivity extensometer. The measured crack-length dependence of the critical stress was in good agreement with the prediction of a stress-intensity analysis that employed a new force-displacement law for the bridging filaments. The analysis required independent experimental evaluation of the matrix fracture toughness, the interfacial sliding friction stress, and the residual tension in the matrix. The matrix-cracking stress for the test specimens without the deliberately introduced cracks was significantly higher than the steady-state cracking stress measured for the long, filament-bridged cracks. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP DANCHAIVIJIT, S (reprint author), UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112, USA. OI Shetty, Dinesh/0000-0003-4132-1372 NR 20 TC 5 Z9 5 U1 0 U2 1 PU AMER CERAMIC SOC 735 CERAMIC PLACE PI WESTERVILLE PA PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1995 VL 78 IS 5 BP 1139 EP 1146 DI 10.1111/j.1151-2916.1995.tb08460.x PG 8 WC Materials Science, Ceramics SC Materials Science GA QZ087 UT WOS:A1995QZ08700001 ER PT J AU OGBUJI, LUJT BRYAN, SR AF OGBUJI, LUJT BRYAN, SR TI THE SIO2-SI3N4 INTERFACE, .1. NATURE OF THE INTERPHASE SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID VAPOR-DEPOSITED SI3N4; N-O SYSTEM; SILICON-NITRIDE; OPTICAL-PROPERTIES; DEPTH RESOLUTION; OXIDATION; OXYNITRIDE; FILMS; SIMS; WET AB Recent reports in the literature have suggested that Si2N2O forms in the oxidation of Si3N4 as a buffer suboxide below the silica crust, and that equilibrium between SiO2 and Si3N4 requires the presence of this buffer. Here we report the examination of SiO2/Si3N4 boundaries of different genesis, by a variety of techniques, all of which failed to detect Si2N2O. What was found in each case is a graded suboxide whose composition merges seamlessly with the higher oxide above and the Si3N4 below. Part I presents the results of compositional depth profiling across the suboxide. In Part II a model is proposed to explain how O-2 diffusion in the graded suboxide limits Si3N4 oxidation kinetics. C1 PERKIN ELMER CORP,DIV PHYS ELECTR,EDEN PRAIRIE,MN 55344. RP OGBUJI, LUJT (reprint author), NASA,LEWIS RES CTR,NYMA,CLEVELAND,OH 44135, USA. NR 32 TC 49 Z9 51 U1 0 U2 5 PU AMER CERAMIC SOC 735 CERAMIC PLACE PI WESTERVILLE PA PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1995 VL 78 IS 5 BP 1272 EP 1278 DI 10.1111/j.1151-2916.1995.tb08481.x PG 7 WC Materials Science, Ceramics SC Materials Science GA QZ087 UT WOS:A1995QZ08700022 ER PT J AU OGBUJI, LUJT AF OGBUJI, LUJT TI THE SIO2-SI3N4 INTERFACE .2. O-2 PERMEATION AND OXIDATION REACTION SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID VAPOR-DEPOSITED SI3N4; SILICON OXYNITRIDE; GLASSES AB Previous analyses of Si3N4 oxidation on the basis of diffusion control by a suboxide layer yielded impossibly high N-2 pressures. Those models assumed interfacial reactions as the oxidation mechanism. However, it is now thought that the oxidation process is in situ substitution of O for N in silicon oxynitride of graded composition rather than interfacial reaction. In this paper, diffusional and thermodynamic analyses appropriate to this mode of oxidation are developed for both the permeation and reaction aspects of oxidation; O-2 diffusivities are calculated from permeation energies;gas pressures in the oxide are derived from solution thermodynamics and found to be moderate. RP OGBUJI, LUJT (reprint author), NASA,LEWIS RES CTR,NYMA,CLEVELAND,OH 44135, USA. NR 37 TC 36 Z9 38 U1 0 U2 0 PU AMER CERAMIC SOC 735 CERAMIC PLACE PI WESTERVILLE PA PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1995 VL 78 IS 5 BP 1279 EP 1284 DI 10.1111/j.1151-2916.1995.tb08482.x PG 6 WC Materials Science, Ceramics SC Materials Science GA QZ087 UT WOS:A1995QZ08700023 ER PT J AU BRYANT, A ALBIN, S EGALON, CO ROGOWSKI, RS AF BRYANT, A ALBIN, S EGALON, CO ROGOWSKI, RS TI CHANGES IN THE AMOUNT OF CORE LIGHT INJECTION FOR FLUORESCENT-CLAD OPTICAL-FIBER DUE TO VARIATIONS IN THE FIBER REFRACTIVE-INDEX AND CORE RADIUS - EXPERIMENTAL RESULTS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article AB Experiments were conducted to quantify the amount of light injected from a thin film of fluorescent sources confined at the core and cladding interface of an optical fiber, also referred to as a fluorosensor. Conditions necessary for high injection of fluorescent Light, previously predicted by a theoretical model, have now been experimentally verified. The results show that, for side excitation, light injection from the thin-film source into guided modes increases with the fiber diameter and the difference between the core and the cladding refractive indices, n(core) - n(clad). C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23681. RP BRYANT, A (reprint author), OLD DOMINION UNIV,NORFOLK,VA 23529, USA. NR 13 TC 4 Z9 4 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAY PY 1995 VL 12 IS 5 BP 904 EP 906 DI 10.1364/JOSAB.12.000904 PG 3 WC Optics SC Optics GA QW725 UT WOS:A1995QW72500021 ER PT J AU GIAPIS, KP MOORE, TA MINTON, TK AF GIAPIS, KP MOORE, TA MINTON, TK TI HYPERTHERMAL NEUTRAL BEAM ETCHING SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 41st National Symposium of the American-Vacuum-Society CY OCT 24-28, 1994 CL DENVER, CO SP Amer Vacuum Soc ID COLLISION-INDUCED DESORPTION; CL2 MOLECULAR-BEAM; LIQUID SURFACES; SILICON; ATOMS; GAS; DISTRIBUTIONS; TRANSITION; SCATTERING; MECHANISMS C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. MONTANA STATE UNIV,CTR BIOFILM ENGN,BOZEMAN,MT 59717. MONTANA STATE UNIV,DEPT CHEM & BIOCHEM,BOZEMAN,MT 59717. RP GIAPIS, KP (reprint author), CALTECH,DIV CHEM & CHEM ENGN,PASADENA,CA 91125, USA. NR 42 TC 69 Z9 69 U1 3 U2 8 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 MAY-JUN PY 1995 VL 13 IS 3 BP 959 EP 965 DI 10.1116/1.579658 PN 1 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA RD766 UT WOS:A1995RD76600087 ER PT J AU MCADOO, J TUNNEY, J AF MCADOO, J TUNNEY, J TI MOVING CCDS CREATE IMAGE WITH LARGE FIELD-OF-VIEW SO LASER FOCUS WORLD LA English DT Editorial Material C1 PARKER HANNIFIN CORP,DAEDAL DIV,HARRISON CITY,PA. RP MCADOO, J (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 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 MAY PY 1995 VL 31 IS 5 BP 233 EP 235 PG 3 WC Optics SC Optics GA QY219 UT WOS:A1995QY21900041 ER PT J AU VARY, A AF VARY, A TI NDE IN THE AGE OF FASTER, BETTER, CHEAPER WITH IMPLICATIONS FOR STRUCTURAL COMPOSITES SO MATERIALS EVALUATION LA English DT Article RP VARY, A (reprint author), NASA,LEWIS RES CTR,STRUCT INTEGR BRANCH,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAY PY 1995 VL 53 IS 5 BP 576 EP 578 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA QY470 UT WOS:A1995QY47000007 ER PT J AU SINGH, M BEHRENDT, DR AF SINGH, M BEHRENDT, DR TI REACTIVE MELT INFILTRATION OF SILICON-MOLYBDENUM ALLOYS INTO MICROPOROUS CARBON PREFORMS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE SILICON; MOLYBDENUM; ALLOYS; CARBON; MELTING ID CARBIDE; WETTABILITY; MECHANISM; SYSTEMS AB Investigations on the reactive melt infiltration of silicon-1.7 and 3.2 at.% molybdenum alloys into microporous carbon preforms have been carried out by modeling, differential thermal analysis (DTA), and melt infiltration experiments. These results indicate that the pore volume fraction of the carbon perform is a very important parameter in determining the final composition of the reaction-formed silicon carbide and the secondary phases. Various undesirable melt infiltration results, e.g. choking-off, specimen cracking, silicon veins, and lake formation, and their correlation with inadequate preform properties are presented. The liquid silicon-carbon reaction exotherm temperatures are influenced by the pore and carbon particle size of the preform and the compositions of infiltrants. Room temperature flexural strength and fracture toughness of materials made by the silicon-3.2 at.% molybdenum alloy infiltration of medium pore size preforms are also discussed. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP SINGH, M (reprint author), CASE WESTERN RESERVE UNIV,DEPT MAT SCI & ENGN,CLEVELAND,OH 44106, USA. NR 24 TC 68 Z9 76 U1 1 U2 11 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY PY 1995 VL 194 IS 2 BP 193 EP 200 DI 10.1016/0921-5093(94)09663-5 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA QY297 UT WOS:A1995QY29700010 ER PT J AU HUTCHINSON, TM WHALEN, RT CLEEK, TM VOGEL, JM ARNAUD, SB AF HUTCHINSON, TM WHALEN, RT CLEEK, TM VOGEL, JM ARNAUD, SB TI FACTORS IN DAILY PHYSICAL-ACTIVITY RELATED TO CALCANEAL MINERAL DENSITY IN MEN SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE BONE MINERAL DENSITY; MUSCULOSKELETAL LOADING; ACTIVITY LEVEL; ACTIVITY EVALUATION; SINGLE ENERGY X-RAY DENSITOMETER; STEPMETERS ID BONE-DENSITY; LUMBAR SPINE; WOMEN; AGE AB To determine the factors in daily physical activity that influence the mineral density of the calcaneus, we recorded walking steps and the type and duration of exercise in 43 healthy 26-to 51-yr-old men. Areal(g . cm(-2)) calcaneal bone mineral density (CBMD) was measured by single energy x-ray densitometry (SXA, Osteon, Inc., Wahiawa, HI). Subjects walked a mean (+/-SD) of 7902 (+/-2534) steps per day or approximately 3.9 (+/-1.2) miles daily. Eight subjects reported no exercise activities. The remaining 35 subjects spent 143 (2-772) (median and range) min . wk(-1) exercising. Twenty-eight men engaged in exercise activities that generate single leg peak Vertical ground reaction forces (GRF(z)) of 2 or more body weights (high loaders, HL), and 15 reported exercise or daily activities that typically generate GRF(z) less than 1.5 body weights (low loaders, LL). CBMD was 12% higher in HL than LL (0.668 +/- 0.074 g . cm(-2) vs 0.597 +/- 0.062 g . cm(-2), P < 0.004). In the HL group, CBMD correlated to reported minutes of high load exercise (r = 0.41, P < 0.03). CBMD was not related to the number of daily walking steps (N = 43, r = 0.03, NS). The results of this study support the concept that the dominant factor in daily physical activity relating to bone mineral density is the participation in site specific high loading activities, i.e., for the calcaneus, high calcaneal loads. C1 UNIV CALIF DAVIS,SCH MED,DAVIS,CA 95616. RP HUTCHINSON, TM (reprint author), NASA,AMES RES CTR,DIV LIFE SCI,MS 239-11,MOFFETT FIELD,CA 94035, USA. NR 25 TC 15 Z9 15 U1 1 U2 1 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0195-9131 J9 MED SCI SPORT EXER JI Med. Sci. Sports Exerc. PD MAY PY 1995 VL 27 IS 5 BP 745 EP 750 PG 6 WC Sport Sciences SC Sport Sciences GA QW449 UT WOS:A1995QW44900018 PM 7674880 ER PT J AU ASTHANA, R AF ASTHANA, R TI AN ANALYSIS FOR SPREADING KINETICS OF LIQUID-METALS ON SOLIDS SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Note ID BORON-NITRIDE; WETTABILITY; ALUMINUM; DYNAMICS; SYSTEM RP ASTHANA, R (reprint author), NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 17 TC 20 Z9 21 U1 1 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5623 EI 1543-1940 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD MAY PY 1995 VL 26 IS 5 BP 1307 EP 1311 DI 10.1007/BF02670625 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA QV327 UT WOS:A1995QV32700030 ER PT J AU BOGARD, DD AF BOGARD, DD TI IMPACT AGES OF METEORITES - A SYNTHESIS SO METEORITICS LA English DT Review ID CRETACEOUS TERTIARY BOUNDARY; CHONDRITE PARENT BODIES; RB-SR; SM-ND; AR-40-AR-39 AGES; LL-CHONDRITES; MELT ROCKS; AR AGES; I-XE; COSMOGENIC NUCLIDES AB Isotopic ages of meteorites that indicate chronometer resetting due to impact heating are summarized. Most of the ages were obtained by the Ar-39-Ar-40 technique, but several Rb-Sr, Pb-Pb, and Sm-Nd ages also suggest some degree of impact resetting. Considerations of experimental data on element diffusion in silicates suggest that various isotopic chronometers ought to differ in their ease of resetting during shock heating in the order K-Ar (easiest), Rb-Sr, Pb-Pb, and Sm-Nd, which is approximately the order observed in meteorites. Partial rather than total chronometer resetting by impacts appears to be the norm; consequently, interpretation of the event age is not always straightforward. Essentially all Ar-39-Ar-40 ages of eucrites and howardites indicate partial to total resetting in the relatively narrow time interval of 3.4-4.1 Ga ago (1 Ga = 10(9) years). Several disturbed Rb-Sr ages appear consistent with this age distribution. This grouping of ages and the brecciated nature of many eucrites and all howardites argues for a large-scale impact bombardment of the HED parent body during the same time period that the Moon received its cataclysmic bombardment. Other meteorite parent bodies such as those of mesosiderites, some chondrites, and IIE irons also may have experienced this bombardment. These data suggest that the early bombardment was not lunar specific but involved much of the inner Solar System, and may have been caused by breakup of a larger planetismal. Although a few chondrites show evidence of age resetting similar to 3.5-3.9 Ga ago, most impact ages of chondrites tend to fall below 1.3 Ga in age. A minimum of similar to 4 impact events, including events at 0.3, 0.5, 1.2, and possibly 0.9 Ga appear to be required to explain the younger ages of H, L, and LL chondrites, although additional events are possible. Most L chondrites show evidence of shock, and the majority of Ar-39-Ar-40 ages of L chondrites fall near 0.5 Ga. The L chondrite parent body apparently experienced a major impact at this time, which map have disrupted it. The observations (1) that lunar highland rocks experienced major impact resetting of various isotopic chronometers similar to 3.7-4.1 Ga ago; (2) that the HED parent body experienced widespread impact resetting of the K-Ar chronometer but only modest disturbance of other isotopic systems, during a similar time period; (3) that ordinary chondrite parent bodies show much more recent and less extensive impact resetting; and (4) that impacts, which initiated cosmic-ray exposure of most stone meteorites almost never reset isotopic chronometers, may all be a consequence of relative parent body size. Greater degrees of isotopic chronometer resetting occur in larger and warmer impact ejecta deposits that cool slowly. The relatively greater size of bodies like the Moon and Vesta (assumed to be the parent asteroid of HED meteorites) both permit such favorable ejecta deposits to occur more easily compared to smaller parent bodies (generally assumed for chondrites) and also protect parent objects from collisional disruption. Thus, impacts on larger bodies would tend to more easily reset chronometers, consistent with the observed relative ease of resetting of Moon (easiest), HED, chondrites and of K-Ar (easiest), Rb-Sr, other chronometers. In contrast, the more recent impact ages of chondrites are postulated to represent collisional disruption of smaller parent objects whose fragments are more readily removed from the meteorite source reservoirs. Impacts that initiate cosmic-ray exposure are mostly small in scale and produce little heating. RP NASA, LYNDON B JOHNSON SPACE CTR, CODE SN4, HOUSTON, TX 77058 USA. NR 195 TC 209 Z9 209 U1 2 U2 13 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 0026-1114 J9 METEORITICS JI Meteoritics PD MAY PY 1995 VL 30 IS 3 BP 244 EP 268 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA QY294 UT WOS:A1995QY29400004 ER PT J AU MCCOY, TJ EHLMANN, AJ KEIL, K AF MCCOY, TJ EHLMANN, AJ KEIL, K TI THE TRAVIS COUNTY, TEXAS, METEORITES SO METEORITICS LA English DT Article ID ORDINARY CHONDRITES; METAMORPHISM AB Studies of 52 specimens recovered from the find site of the original Travis County meteorite reveal the presence of two distinct meteorites. Travis County (a), which includes the original Travis County meteorite. is the more abundant meteorite and is classified as an H5(S4) shock-blackened chondrite. Travis County (b) is classified as an H4(S2) chondrite with rare chondritic clasts of H group parentage, indicating that the meteorite is a breccia. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. TEXAS CHRISTIAN UNIV,DEPT GEOL,FT WORTH,TX 76129. RP MCCOY, TJ (reprint author), UNIV HAWAII,SCH OCEAN & EARTH SCI & TECHNOL,HAWAII INST GEOPHYS & PLANETOL,HONOLULU,HI 96822, USA. NR 19 TC 3 Z9 3 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 MAY PY 1995 VL 30 IS 3 BP 348 EP 351 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA QY294 UT WOS:A1995QY29400014 ER PT J AU JONES, JH AF JONES, JH TI FRACTIONAL CRYSTALLIZATION OF IRON-METEORITES - CONSTANT VERSUS CHANGING PARTITION-COEFFICIENTS - REPLY SO METEORITICS LA English DT Note RP JONES, JH (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SN4,HOUSTON,TX 77058, USA. NR 5 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 MAY PY 1995 VL 30 IS 3 BP 354 EP 356 PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA QY294 UT WOS:A1995QY29400016 ER PT J AU RHIM, WK AF RHIM, WK TI MATERIALS PROCESSING BY HIGH-TEMPERATURE ELECTROSTATIC LEVITATION SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article ID PARTICLES; DROPS AB In electrostatic containerless materials processing a sample is levitated in a high vacuum by electrostatic forces, melted and various experiments are performed over a broad temperature range around its melting temperature. Since the sample is isolated from container walls, the purity of sample is preserved, and a molten drop can be highly undercooled. Once a drop is isolated in a clean environment, a number of non-contact diagnostic techniques can be implemented for the measurements of various thermophysical properties as a function of drop temperature, and it will also make investigations of nucleation mechanism as well as formation of metastable crystalline and amorphous phases,vith novel properties. The High-Temperature High-Vacuum Electrostatic Levitation Facility (HTESL) at JPL was developed under NASA's support and is one-of-a-kind in the world which is extremely well suited to meet these requirements. Some useful characteristics of the high temperature electrostatic levitator (HTESL) are: (I) It can process various materials which include metals, semiconductors, and insulators. (2) Since the sample heating and levitation mechanisms are completely decoupled, the range of sample tempelatllre is not limited by the levitation mechanism. (3) Since the pro processing environment is a high vacuum, sample cooling in the absence of heating can be rigorously described by a purely radiative heat transfer equation. (4) Employment of feedback position control allows quiescent sample positioning. (5) It provides an open environment so that a sample can he viewed by various non-contact diagnostic instruments. Following a brief description of this new technique in comparison with other similar techniques, the present status of this technique with respect to the studies of thermophysical properties, nucleation mechanisms, and metastable phases is described. RP RHIM, WK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 25 TC 5 Z9 5 U1 2 U2 4 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 860420, W-8163 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PD MAY PY 1995 VL 8 IS 1 BP 46 EP 51 PG 6 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA QW533 UT WOS:A1995QW53300006 ER PT J AU KROES, RL REISS, DA LEHOCZKY, SL AF KROES, RL REISS, DA LEHOCZKY, SL TI NUCLEATION OF CRYSTALS FROM SOLUTION IN MICROGRAVITY - USML-1 GLOVEBOX (GBX) INVESTIGATION SO MICROGRAVITY SCIENCE AND TECHNOLOGY LA English DT Article AB A new method for initiating nucleation from solutions in microgravity which avoids nucleation on container walls and other surfaces is described. This method consists of injecting a small quantity of highly concentrated, heated solution into the interior of a slightly supersaturated, cooler host growth solution. It was tested successfully on USML-1, producing a large number of LAP crystals whose longest dimension averaged 1 mm. RP KROES, RL (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 860420, W-8163 MUNICH, GERMANY SN 0938-0108 J9 MICROGRAVITY SCI TEC JI Microgravity Sci. Technol. PD MAY PY 1995 VL 8 IS 1 BP 52 EP 55 PG 4 WC Engineering, Aerospace; Thermodynamics; Mechanics SC Engineering; Thermodynamics; Mechanics GA QW533 UT WOS:A1995QW53300007 ER PT J AU KIM, GT DUVAL, WMB GLICKSMAN, ME SINGH, NB AF KIM, GT DUVAL, WMB GLICKSMAN, ME SINGH, NB TI THERMAL CONVECTIVE EFFECTS ON PHYSICAL VAPOR TRANSPORT GROWTH OF MERCUROUS CHLORIDE (HG2CL2) CRYSTALS FOR AXISYMMETRICAL 2D CYLINDRICAL ENCLOSURE SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Article ID TEMPERATURE AB The effects of thermal convection are investigated for the physical vapor transport (PVT) crystal growth process of Hg2Cl2 crystals. These effects may lead to increased defect densities and reduced optical homogeneity of the resultant crystals. A two-dimensional axisymmetrical model has been developed and applied to simulate the fluid flow, temperature, and mass concentration distribution in closed ampoules during PVT crystal growth. The numerical parametric studies show that the growth rate increases with the one-quarter power of the Rayleigh number, Ra-0.25, for 0 less than or equal to Delta T less than or equal to 30 K (0 less than or equal to Ra less than or equal to 2.62 x 10(3)), and with Ra-1.5 in the temperature range of 30 less than or equal to Delta T less than or equal to 50 K (2.62 x 10(3) less than or equal to Ra less than or equal to 4.73 x 10(3)). The effect of thermal convection is shown to be negligible for gravitational accelerations less than the order of 10(-1)g(0), for low-aspect-ratio enclosures. The growth rate of Hg2Cl2 decreases exponentially with an increase in the partial pressure of an impurity B, as well as with a decrease in the ampoule aspect ratio AR (radius to transport length) for 0.05 less than or equal to AR less than or equal to 0.20. C1 RENSSELAER POLYTECH INST,DEPT MAT ENGN,TROY,NY 12180. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. WESTINGHOUSE SCI & TECHNOL CTR,PITTSBURGH,PA 15235. OI Glicksman, Martin/0000-0002-2675-2759 NR 32 TC 12 Z9 12 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD MAY PY 1995 VL 3 IS 3 BP 331 EP 357 DI 10.1088/0965-0393/3/3/004 PG 27 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA RA327 UT WOS:A1995RA32700004 ER PT J AU SANTOSLLEO, M CLAVEL, J BARR, P GLASS, IS PELAT, D PETERSON, BM REICHERT, G AF SANTOSLLEO, M CLAVEL, J BARR, P GLASS, IS PELAT, D PETERSON, BM REICHERT, G TI MULTIFREQUENCY MONITORING OF THE SEYFERT-1 GALAXY NGC-4593 .2. A SMALL, COMPACT NUCLEUS SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE GALAXIES, INDIVIDUAL, NGC 4593; GALAXIES, NUCLEI; GALAXIES, SEYFERT; INFRARED, GALAXIES; ULTRAVIOLET, GALAXIES; X-RAYS, GALAXIES ID ACTIVE GALACTIC NUCLEI; EMISSION-LINE REGION; X-RAY REFLECTION; ACCRETION DISKS; ULTRAVIOLET VARIABILITY; DETAILED OBSERVATIONS; ENERGY-DISTRIBUTIONS; COLD MATTER; HOT DUST; QUASARS AB We discuss the results of a campaign to monitor spectral variations in the low-luminosity Seyfert 1 galaxy NGC4593, at X-ray, ultraviolet, optical and near-IR frequencies. The observations and data analysis have been described in a companion paper. The active nucleus in this galaxy is strongly and rapidly variable in all wavebands, implying that the continuum source is unusually compact. Its energy distribution from 1.2 mu m to 1200 Angstrom obeys a power law which is significantly steeper than is usual in Seyferts or QSOs; the 'big bump' is either absent or shifted to wavelengths shorter than 1200 Angstrom. The variations of the soft X-ray excess do not correlate with those of the UV or hard X-ray continuum. The far UV and optical fluxes are well correlated, while the correlation between the hard X-rays and 1447-Angstrom continuum is only marginally significant. Moreover, the optical flux cannot lag behind the UV by more than 6 d. These results cannot be accommodated in the framework of the standard geometrically thin accretion disc model. Rather, they suggest that the bulk of the UV and optical flux originates from thermal reprocessing of X-rays irradiating the disc. The soft X-ray excess is probably the only spectral component that originates from viscous dissipation inside the disc, and the near-infrared is probably emitted by hot dust heated by the UV radiation. Such a model is consistent with NGC 4593 having a relatively small black hole mass of the order of 2x10(6) M. as inferred from the line variability study. The high-ionization/excitation emission lines are very broad and strongly variable, and their variations correlate with those of the continuum. The low-excitation lines are significantly narrower and remain constant within the accuracy of our measurements. These results suggest a stratified broad-line region, where the degree of ionization and the velocity dispersion of the gas increase toward small radii. The Ly alpha lambda 1216 line responds to the variations of the continuum with a delay of less than or equal to 4 d. To a first-order approximation, the broad-line region in NGC 4593 is well modelled by two different zones at distances of similar to 15 and 3 light-day from the ionizing source respectively. C1 ESA IUE OBSERV,E-28080 MADRID,SPAIN. ESTEC,ISO OBSERV,2200 AG NOORDWIJK,NETHERLANDS. S AFRICAN ASTRON OBSERV,CAPE TOWN 7935,SOUTH AFRICA. OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SANTOSLLEO, M (reprint author), OBSERV PARIS,DAEC,F-92195 MEUDON,FRANCE. NR 68 TC 23 Z9 23 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 1995 VL 274 IS 1 BP 1 EP 19 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QX956 UT WOS:A1995QX95600007 ER PT J AU MASON, KO DREW, JE CORDOVA, FA HORNE, K HILDITCH, R KNIGGE, C LANZ, T MEYLAN, T AF MASON, KO DREW, JE CORDOVA, FA HORNE, K HILDITCH, R KNIGGE, C LANZ, T MEYLAN, T TI ECLIPSE OBSERVATIONS OF AN ACCRETION DISC WIND SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ACCRETION, ACCRETION DISCS; LINE, PROFILES; BINARIES, ECLIPSING; STARS, INDIVIDUAL, UX UMA; NOVAE, CATACLYSMIC VARIABLES; ULTRAVIOLET, STARS ID UX-URSAE-MAJORIS; CATACLYSMIC VARIABLES; DWARF NOVA; RESONANCE LINES; OUTBURST; EMISSION; PROFILES; MASS AB The Goddard High Resolution Spectrometer on the Hubble Space Telescope has been used to monitor, through eclipse, the CIV 1550-Angstrom and HeII 1640-Angstrom lines in the spectrum of the nova-like cataclysmic variable UX UMa. Previous work has suggested that the Cry line arises in an accretion disc wind. The HST data confirm this, in that the line shows a broad, asymmetric emission profile. However, superimposed on the emission are previously unsuspected narrow absorption components at the rest wavelengths of the doublet. The absorption disappears during the continuum eclipse, causing the net continuum-subtracted flux near line centre to increase by about 20 per cent during this time. The mid-eclipse line profile shows the classic asymmetric shape expected for a bipolar wind viewed edge-on. The various wavelength segments within the CIV line exhibit different eclipse light curves. The flux at line centre declines gradually, beginning at least 0.05 in orbital phase before the continuum eclipse, then rising sharply coincident with continuum ingress due to loss of the absorption components, Flux is also lost from the red wing of the CIV line beginning just before (Delta phi similar to 0.02) the onset of continuum eclipse. The red wing flux declines more slowly than the continuum itself, reaching a minimum after the time of continuum mid-eclipse. This suggests that the emitting gas may have a significant rotational component about the white dwarf. However, the blue wing shows no comparable signature of rotation. These data show that the shallowness of the line flux eclipse is primarily due to occultation of regions of net absorption, with the implication that the line-forming region can be smaller than the companion star. To explain the appearance and eclipse evolution of the CIV line profile solely in terms of outflow will require a highly collimated disc wind. Alternatively the narrow, superposed absorption components may originate elsewhere in the system. These data also provide the first clear demonstration that HeII 1640 Angstrom is mainly a wind-formed feature. C1 UNIV OXFORD, DEPT PHYS, NUCL & ASTROPHYS LAB, OXFORD OX1 3RH, ENGLAND. PENN STATE UNIV, DEPT ASTRON, STATE COLLEGE, PA 16802 USA. UNIV UTRECHT, STERREKUNDIG INST, 3058 TA UTRECHT, NETHERLANDS. UNIV ST ANDREWS, DEPT PHYS & ASTRON, ST ANDREWS KY16 9SS, FIFE, SCOTLAND. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. GEORGIA STATE UNIV, ATLANTA, GA 30303 USA. RP UCL, MULLARD SPACE SCI LAB, HOLMBURY ST MARY, DORKING RH5 6NT, SURREY, ENGLAND. NR 32 TC 27 Z9 27 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAY 1 PY 1995 VL 274 IS 1 BP 271 EP 286 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QX956 UT WOS:A1995QX95600031 ER PT J AU KARYAMPUDI, VM KAPLAN, ML KOCH, SE ZAMORA, RJ AF KARYAMPUDI, VM KAPLAN, ML KOCH, SE ZAMORA, RJ TI THE INFLUENCE OF THE ROCKY-MOUNTAINS ON THE 13-14 APRIL 1986 SEVERE WEATHER OUTBREAK .1. MESOSCALE LEE CYCLOGENESIS AND ITS RELATIONSHIP TO SEVERE WEATHER AND DUST STORMS SO MONTHLY WEATHER REVIEW LA English DT Article ID HORIZONTAL PRESSURE-GRADIENT; SCALE NUMERICAL SIMULATIONS; ALONG-STREAM CIRCULATIONS; PRESIDENTS DAY CYCLONE; 18-19 FEBRUARY 1979; JET STREAK; WAVE DISTURBANCES; ENVIRONMENT; FRONTOGENESIS; SURFACE AB In this first of a two paper series, a sequence of dynamical processes involving the evolution of a mesoscale lee cyclone and its subsequent interaction with a mesoscale tropopause fold downstream of the Rocky Mountains is investigated. These scale-interactive phenomena, which resulted from the jet streak interaction with the topography, were examined in detail using the observational data obtained from the Program for Regional Observing and Forecasting Services' mesonetwork and wind profilers, as well as conventional surface and rawinsonde data and Total Ozone Mapping Spectrometer satellite data over the Colorado region for the severe weather event that occurred during 13-14 April 1986. Large-scale analysis indicated that as a baroclinic low pressure system approached the Rockies with its attendant upper-level jet streak, a typical prestorm environment over western Kansas formed in the early morning hours of 13 April. Hourly mesonet data analysis revealed the formation and eastward progression of a mesoscale lee cyclone with a trailing wind-shift line identified as an internal bore initiated by a cold front (i.e., a prefrontal bore) in Part II. Analysis of winds and divergence including diagnostically derived temperature and height fields from Colorado wind profilers indicated that as the jet streak momentum propagated into a less stable region in the midtroposphere created by low-level adiabatic warming and midlevel cooling on the leeside of the Rockies, unbalanced flow conditions resulted at scales less than the Rossby radius of deformation. As a consequence of geostrophic adjustment processes, mesoscale tropopause folding and upper-level frontogenesis occurred over the profiler network, Unbalanced upper-level frontogenesis resulted from the tilting of the isentropes by along-stream ageostrophic indirect circulations comprised of horizontal vertical velocity gradients across the tropopause fold. As the mesoscale tropopause fold extruded downwards to midlevels in association with the descending secondary upper-level jet streak forced by the geostrophic adjustment process, lee cyclogenesis occurred due to the phasing of the upper-level front with the low-level lee cyclone. Synthesis of the mesonetwork and profiler observations suggest that high momentum in the midtroposphere associated with the descending branch of the jet stream just ahead of the tropopause fold was entrained and mixed downward to the surface by the growing boundary layer that developed ahead of the prefrontal bore but behind the dryline. This surge of southwesterly momentum at the surface, largely responsible for blowing dust, was mostly ageostrophic and contributed to an increase in surface vorticity and moisture convergence as well as frontogenesis around the lee cyclone, A mesoscale conceptual model is proposed in order to explain the dynamical Sequence of events involving lee cyclogenesis, dust storms, and a tropopause fold that led to the severe weather environment over the Great Plains. In the companion paper (Part II), observational evidence of an internal bore occurring ahead of a cold front and comparisons with simple numerical model results are presented in order to understand the initiation and propagation of the prefrontal bore and its influence in triggering a squall line farther downstream. C1 N CAROLINA STATE UNIV, DEPT MARINE EARTH & ATMOSPHER SCI, RALEIGH, NC 27695 USA. NOAA, ERL, WAVE PROPAGAT LAB, BOULDER, CO 80303 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, CODE 6912, GREENBELT, MD 20771 USA. NR 83 TC 14 Z9 14 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1995 VL 123 IS 5 BP 1394 EP 1422 DI 10.1175/1520-0493(1995)123<1394:TIOTRM>2.0.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV855 UT WOS:A1995QV85500010 ER PT J AU KARYAMPUDI, VM KOCH, SE CHEN, C ROTTMAN, JW KAPLAN, ML AF KARYAMPUDI, VM KOCH, SE CHEN, C ROTTMAN, JW KAPLAN, ML TI THE INFLUENCE OF THE ROCKY-MOUNTAINS OH THE 13-14 APRIL 1986 SEVERE WEATHER OUTBREAK .2. EVOLUTION OF A PREFRONTAL BORE AND ITS ROLE IN TRIGGERING A SQUALL LINE SO MONTHLY WEATHER REVIEW LA English DT Article ID ATMOSPHERIC UNDULAR BORE; MORNING GLORY; COORDINATE TRANSFORMATION; GRAVITY-WAVES; COLD FRONTS; MODEL; WINDS; CCOPE; FLOW AB In this paper, Part II of a series, the evolution of a prefrontal bore on the leeside of the Rockies and its subsequent propagation and initiation of convection farther downstream over eastern Colorado and western Nebraska are investigated. The observational evidence for this sequence of events was obtained from combined i analyses of high-resolution GOES satellite imagery and Program for Regional Observing and Forecasting Services mesonetvork data over the Colorado region for the severe weather event that occurred during 13-14 April 1986. A 2D nonhydrostatic numerical model is used to further understand the initiation of the bore and its ability to propagate farther downstream and trigger Convection. Analysis of satellite imagery and mesonet data indicated that an internal bore (ahead of a cold front), a moderate downslope windstorm, and a quasi-stationary hydraulic jump were generated within a few hours along the leeslope as a Pacific cold front and its attendant upper-level jet streak advanced over the Rockies. The bore and the cold front then propagated eastward for several hours and interacted with a lee cyclone, a dryline, and a warm front, initiating severe weather over Nebraska and Kansas. Wave-ducting analysis showed that favorable wave-trapping mechanisms such as a capping inversion above a neutral layer and wind curvature from a low-level jet, which appeared to be the most dominant ducting mechanism, existed across eastern Colorado and western Nebraska to maintain the bore strength, Numerical simulations of continuously stratified shear flow specified from upstream and downstream soundings suggested that the creation of a density current along the lee slopes, a downstream inversion height lower than the upstream inversion height; and a strong curvature in the wind profile of the low-level jet are all needed to initiate and sustain the integrity of the propagating bore. Based on the synthesis of observational analyses and 2D nonhydrostatic model simulations, a schematic illustration of the time evolution of the bore ahead of the Pacific cold front, the hydraulic jump associated with a mountain wave, and the arctic air intrusion from the north to the lee of the Rockies are presented in the context of severe weather occurrence over western Nebraska and Kansas. C1 N CAROLINA STATE UNIV, DEPT MARINE EARTH & ATMOSPHER SCI, RALEIGH, NC 27695 USA. RP NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, CODE 912, GREENBELT, MD 20771 USA. NR 48 TC 30 Z9 30 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1995 VL 123 IS 5 BP 1423 EP 1446 DI 10.1175/1520-0493(1995)123<1423:TIOTRM>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV855 UT WOS:A1995QV85500011 ER PT J AU MOORTHI, S HIGGINS, RW BATES, JR AF MOORTHI, S HIGGINS, RW BATES, JR TI A GLOBAL MULTILEVEL ATMOSPHERIC MODEL USING A VECTOR SEMI-LAGRANGIAN FINITE-DIFFERENCE SCHEME .2. VERSION WITH PHYSICS SO MONTHLY WEATHER REVIEW LA English DT Article ID AREA GRIDPOINT MODEL; PRIMITIVE-EQUATIONS; PARAMETERIZATION; SEMIIMPLICIT; REGION AB Full physical parameterizations have been incorporated into the global model using a two-time-level, semi-Lagrangian, semi-implicit finite-difference integration scheme that was described in Part I of this work. Virtual temperature effects have also been incorporated into the adiabatic part of the model. The diurnal and seasonal cycles have been included, with prescribed seasonally varying climatological surface boundary conditions. The model has been integrated in both forecast and climate mode, at a resolution of 2 degrees x 2.5 degrees in latitude/longitude, 20 levels in the vertical, and a time step of 45 min for the dynamics: Medium-range forecasts using January and July initial conditions give highly encouraging anomaly correlation skill scores. Two parallel 17-month climate simulations, one without and one with mass restoration, show that the model successfully simulates many features of the observed climate. Mass restoration is shown to have no significant impact on the seasonally averaged climate statistics. C1 NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. NOAA, NATL WEATHER SERV, NATL METEOROL CTR, DIV DEV, WASHINGTON, DC 20233 USA. NOAA, NATL WEATHER SERV, NATL METEOROL CTR, CTR CLIMATE ANAL, WASHINGTON, DC 20233 USA. NR 33 TC 28 Z9 29 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 1995 VL 123 IS 5 BP 1523 EP 1541 DI 10.1175/1520-0493(1995)123<1523:AGMAMU>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV855 UT WOS:A1995QV85500016 ER PT J AU MCGEE, TJ GROSS, MR SINGH, UN BUTLER, JJ KIMVILAKANI, PE AF MCGEE, TJ GROSS, MR SINGH, UN BUTLER, JJ KIMVILAKANI, PE TI IMPROVED STATROSPHERIC OZONE LIDAR SO OPTICAL ENGINEERING LA English DT Article DE OZONE LIDAR; RAMAN DIAL; TEMPERATURE LIDAR ID STRATOSPHERIC OZONE; RAMAN LIDAR; AEROSOL AB The NASA Goddard Space Flight Center's stratospheric ozone lidar has undergone several modifications and improvements since it participated in the Stratospheric Ozone Intercomparison (STOIC) campaign at Table Mountain, CA, in July 1989. Changes have been made in both the transmitter and receiver. The transmitter has been changed to include a XeF laser to generate the ''off-line'' wavelength; the detector has been changed to include mechanical choppers for each of the high-sensitivity channels, and the number of channels has been increased to six. In addition to the four elastic-scattering channels previously described, detectors at the N-2 Raman-scattered wavelengths for each of the transmitted wavelengths have also been added. The vertical resolution of the acquisition has been improved from 300 to 150 m, with the capability to record data with 75-m resolution. The Raman channels permit the measurement of ozone in air parcels with heavy loadings of aerosols, and give additional information about the aerosols themselves. Data from recent campaigns are presented to illustrate these points. C1 HUGHES STX CORP,LANHAM,MD 20706. NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. IDEA CORP,BELTSVILLE,MD 20705. RP MCGEE, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 916,GREENBELT,MD 20771, USA. RI McGee, Thomas/G-4951-2013; Butler, James/D-4188-2013 NR 14 TC 51 Z9 51 U1 0 U2 2 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAY PY 1995 VL 34 IS 5 BP 1421 EP 1430 DI 10.1117/12.199883 PG 10 WC Optics SC Optics GA QX179 UT WOS:A1995QX17900025 ER PT J AU MARKERT, TH CANIZARES, CR NELSON, CS BAUER, JM PUC, B WOODGATE, BE AF MARKERT, TH CANIZARES, CR NELSON, CS BAUER, JM PUC, B WOODGATE, BE TI EVALUATION OF CURVED CRYSTALS FOR COSMIC X-RAY SPECTROSCOPY SO OPTICAL ENGINEERING LA English DT Article DE X-RAY SPECTROMETERS; BRAGG CRYSTALS; SPACECRAFT INSTRUMENTATION ID SPECTROMETER; EMISSION; LINE AB We describe a spectrometer used to evaluate curved crystals, crystals originally intended for cosmic x-ray spectroscopy on the AXAF satellite. The most important feature of the AXAF instrument was the high-resolution spectra (lambda/Delta lambda as high as 2000) that could be obtained from astronomical objects over the lambda range 1.2 to 100 Angstrom. The crystals are formed into narrow cylindrical facets and assembled into a pseudotoroidal surface. The spectral resolution is degraded by a number of effects, which we describe. The primary effect over which we have control is the figure of each cylindrical segment. We measure deviations from the nominal cylindrical shape, which we call Delta theta(slope), using a laboratory x-ray spectrometer. We present spectrometer data for several crystal samples, evaluated at different energies, We compare these results with similar tests performed at optical wavelengths. Our results indicate that the Delta theta(slope) error can be controlled, and that curved crystals with the desired resolving power can be fabricated. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP MARKERT, TH (reprint author), MIT,CTR SPACE RES,ROOM 37-621,CAMBRIDGE,MA 02139, USA. RI Woodgate, Bruce/D-2970-2012 NR 29 TC 0 Z9 0 U1 0 U2 0 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAY PY 1995 VL 34 IS 5 BP 1512 EP 1523 DI 10.1117/12.183992 PG 12 WC Optics SC Optics GA QX179 UT WOS:A1995QX17900037 ER PT J AU LAUNIUS, RD AF LAUNIUS, RD TI A WESTERN MORMON IN WASHINGTON, DC, FLETCHER,JAMES,C., NASA, AND THE FINAL FRONTIER SO PACIFIC HISTORICAL REVIEW LA English DT Article ID SPACE RP LAUNIUS, RD (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 54 TC 3 Z9 4 U1 0 U2 0 PU UNIV CALIF PRESS PI BERKELEY PA JOURNALS DEPT 2120 BERKELEY WAY, BERKELEY, CA 94720 SN 0030-8684 J9 PAC HIST REV JI Pac. Hist. Rev. PD MAY PY 1995 VL 64 IS 2 BP 217 EP 241 PG 25 WC History SC History GA RH313 UT WOS:A1995RH31300003 ER PT J AU COHEN, MM EBENHOLTZ, SM LINDER, BJ AF COHEN, MM EBENHOLTZ, SM LINDER, BJ TI EFFECTS OF OPTICAL PITCH ON OCULOMOTOR CONTROL AND THE PERCEPTION OF TARGET ELEVATION SO PERCEPTION & PSYCHOPHYSICS LA English DT Article ID PERCEIVED EYE LEVEL; VISUAL-FIELD AB In two experiments, we used an ISCAN infrared video system to examine the influence of a pitched visual array on gaze elevation and on judgments of visually perceived eye level. In Experiment 1, subjects attempted to direct their gaze to a relaxed or to a horizontal orientation while they were seated in a room whose walls were pitched at various angles with respect to gravity. Gaze elevation was biased in the direction in which the room was pitched. In Experiment 2, subjects looked into a small box that was pitched at various angles while they attempted simply to direct their gaze alone, or to direct their gaze and place a visual target at their apparent horizon. Both gaze elevation and target settings varied systematically with the pitch orientation of the box. Our results suggest that under these conditions, an optostatic response, of which the subject is unaware, is responsible for the changes in both gaze elevation and judgments of target elevation. C1 SUNY COLL OPTOMETRY,NEW YORK,NY 10010. PERMANENTE MED GRP INC,OAKLAND,CA. RP COHEN, MM (reprint author), NASA,AMES RES CTR,MAIL STOP 239-11,MOFFETT FIELD,CA 94035, USA. OI Ebenholtz, Sheldon/0000-0003-1488-3652 NR 18 TC 16 Z9 16 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 SN 0031-5117 J9 PERCEPT PSYCHOPHYS JI Percept. Psychophys. PD MAY PY 1995 VL 57 IS 4 BP 433 EP 440 DI 10.3758/BF03213069 PG 8 WC Psychology; Psychology, Experimental SC Psychology GA QT988 UT WOS:A1995QT98800002 PM 7596741 ER PT J AU BREZINA, R LIU, WK GREEN, S AF BREZINA, R LIU, WK GREEN, S TI CLOSE-COUPLING CALCULATION OF LINE MIXING IN THE ISOTROPIC RAMAN Q-BRANCH OF D-2 IN HE SO PHYSICAL REVIEW A LA English DT Article ID ROTATIONAL RELAXATION; D2; COLLISIONS; SHAPES; AR C1 NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025. RP BREZINA, R (reprint author), UNIV WATERLOO,DEPT PHYS,GUELPH WATERLOO PROGRAM GRAD WORK PHYS,WATERLOO,ON N2L 3G1,CANADA. NR 21 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 1995 VL 51 IS 5 BP 3645 EP 3649 DI 10.1103/PhysRevA.51.3645 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA RA431 UT WOS:A1995RA43100039 ER PT J AU PRESTAGE, JD TJOELKER, RL MALEKI, L AF PRESTAGE, JD TJOELKER, RL MALEKI, L TI ATOMIC CLOCKS AND VARIATIONS OF THE FINE-STRUCTURE CONSTANT SO PHYSICAL REVIEW LETTERS LA English DT Article ID FREQUENCY STANDARD; LIMITS RP PRESTAGE, JD (reprint author), CALTECH,JET PROP LAB,FREQUENCY STANDARDS LAB,4800 OAK GROVE DR,BLDG 298,PASADENA,CA 91109, USA. NR 30 TC 229 Z9 230 U1 1 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 1 PY 1995 VL 74 IS 18 BP 3511 EP 3514 DI 10.1103/PhysRevLett.74.3511 PG 4 WC Physics, Multidisciplinary SC Physics GA QV149 UT WOS:A1995QV14900003 ER PT J AU BERGER, SA ERLEBACHER, G AF BERGER, SA ERLEBACHER, G TI VORTEX BREAKDOWN INCIPIENCE - THEORETICAL CONSIDERATIONS SO PHYSICS OF FLUIDS LA English DT Article ID CONTAINER; SIMULATION; MODEL; FLOW C1 NASA, LANGLEY RES CTR, INST COMP APPL SCI & ENGN, HAMPTON, VA 23681 USA. RP BERGER, SA (reprint author), UNIV CALIF BERKELEY, DEPT MECH ENGN, BERKELEY, CA 94720 USA. NR 38 TC 10 Z9 10 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 1995 VL 7 IS 5 BP 972 EP 982 DI 10.1063/1.868762 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA QV544 UT WOS:A1995QV54400011 ER PT J AU STRIBLING, T MATTHAEUS, WH OUGHTON, S AF STRIBLING, T MATTHAEUS, WH OUGHTON, S TI MAGNETIC HELICITY IN MAGNETOHYDRODYNAMIC TURBULENCE WITH A MEAN MAGNETIC-FIELD SO PHYSICS OF PLASMAS LA English DT Article ID 3-DIMENSIONAL MAGNETOHYDRODYNAMICS; ALFVENIC FLUCTUATIONS; NUMERICAL-SIMULATION; RELAXATION PROCESSES; SOLAR-WIND; GENERATION; STATES; ENERGY; PLASMA C1 UNIV DELAWARE,BARTOL RES INST,NEWARK,DE 19716. RP STRIBLING, T (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,GREENBELT,MD 20771, USA. RI Oughton, Sean/A-3380-2012 OI Oughton, Sean/0000-0002-2814-7288 NR 34 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1995 VL 2 IS 5 BP 1437 EP 1452 DI 10.1063/1.871359 PG 16 WC Physics, Fluids & Plasmas SC Physics GA QZ330 UT WOS:A1995QZ33000012 ER PT J AU SIREGAR, E GHOSH, S GOLDSTEIN, ML AF SIREGAR, E GHOSH, S GOLDSTEIN, ML TI NONLINEAR ENTROPY PRODUCTION OPERATORS FOR MAGNETOHYDRODYNAMIC PLASMAS SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC RECONNECTION; SPECTRAL METHODS; TURBULENCE; INSTABILITY; DISSIPATION; RESISTIVITY; VISCOSITY; FIELDS C1 NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,GREENBELT,MD 20771. RI Goldstein, Melvyn/B-1724-2008 NR 40 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1995 VL 2 IS 5 BP 1480 EP 1493 DI 10.1063/1.871363 PG 14 WC Physics, Fluids & Plasmas SC Physics GA QZ330 UT WOS:A1995QZ33000016 ER PT J AU STEFFEN, KL WHEELER, RM ARORA, R PALTA, JP TIBBITTS, TW AF STEFFEN, KL WHEELER, RM ARORA, R PALTA, JP TIBBITTS, TW TI BALANCING PHOTOSYNTHETIC LIGHT-HARVESTING AND LIGHT-UTILIZATION CAPACITIES IN POTATO LEAF TISSUE DURING ACCLIMATION TO DIFFERENT GROWTH TEMPERATURES SO PHYSIOLOGIA PLANTARUM LA English DT Article DE ACCLIMATION; CHLOROPHYLL; LIGHT; PHOTOINHIBITION; PHOTOSYNTHESIS; POTATO; RESPIRATION; SOLANUM TUBEROSUM; TEMPERATURE ID DEPENDENT PHOTOINHIBITION; SPINACH LEAVES; PLANTS; FIELD; RYE AB We investigated the effect of temperature during growth and development on the relationship between light-harvesting capacity, indicated by chlorophyll concentration, and light-utilization potential, indicated by light- and bicarbonate-saturated photosynthetic oxygen evolution, in Solanum tuberosum L. cv. Norland. Clonal plantlets were transplanted and grown at 20 degrees C for 2 weeks before transfer to 12, 16, 20, 24 and 28 degrees C for 6 weeks. After 4 weeks of the temperature treatments, leaf tissue fresh weights per area were one-third higher in plants grown at 12 degrees C vs those grown at 28 degrees C. Conversely, chlorophyll content per area in tissue grown at 12 degrees C was less than one-half of that of tissue grown at 28 degrees C at 4 weeks. Photosynthetic capacity measured at a common temperature of 20 degrees C and expressed on a chlorophyll basis was inversely proportional to growth temperature. Leaf tissue from plants grown at 12 degrees C for 4 weeks had photosynthetic rates that were 3-fold higher on a chlorophyll basis than comparable tissue from plants grown at 28 degrees C. These results suggest that the relationship between light-harvesting capacity and light-utilization potential varies 3-fold in response to the growth temperatures examined. The role of this response in avoidance of photoinhibition is discussed. C1 NASA,KENNEDY SPACE CTR,FL 32899. W VIRGINIA UNIV,DIV PLANT & SOIL SCI,MORGANTOWN,WV 26506. UNIV WISCONSIN,DEPT HORT,MADISON,WI 53706. RP STEFFEN, KL (reprint author), PENN STATE UNIV,DEPT HORT,UNIVERSITY PK,PA 16801, USA. NR 25 TC 8 Z9 9 U1 2 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0031-9317 J9 PHYSIOL PLANTARUM JI Physiol. Plant. PD MAY PY 1995 VL 94 IS 1 BP 51 EP 56 DI 10.1034/j.1399-3054.1995.940108.x PG 6 WC Plant Sciences SC Plant Sciences GA QY431 UT WOS:A1995QY43100008 PM 11538413 ER PT J AU STIGLER, RD RUKER, F KATINGER, D ELLIOTT, G HOHNE, W HENKLEIN, P HO, JX KEELING, K CARTER, DC NUGEL, E KRAMER, A PORSTMANN, T SCHNEIDERMERGENER, J AF STIGLER, RD RUKER, F KATINGER, D ELLIOTT, G HOHNE, W HENKLEIN, P HO, JX KEELING, K CARTER, DC NUGEL, E KRAMER, A PORSTMANN, T SCHNEIDERMERGENER, J TI INTERACTION BETWEEN A FAB FRAGMENT AGAINST GP41 OF HUMAN-IMMUNODEFICIENCY-VIRUS-1 AND ITS PEPTIDE EPITOPE - CHARACTERIZATION USING A PEPTIDE EPITOPE LIBRARY AND MOLECULAR MODELING SO PROTEIN ENGINEERING LA English DT Article DE COMPUTER MODEL; GP41; HIV; MONOCLONAL ANTIBODY; PEPTIDE EPITOPE LIBRARY ID NUCLEAR-MAGNETIC-RESONANCE; HUMAN MONOCLONAL-ANTIBODY; 3-DIMENSIONAL STRUCTURE; CRYSTAL-STRUCTURE; ANTIGEN COMPLEX; TRANSMEMBRANE PROTEIN; SYNTHETIC PEPTIDES; COMBINING SITES; BINDING; CONFORMATIONS AB The molecular interaction of the Fab fragment of the human monoclonal antibody 3D6, directed against the transmembrane protein gp41 of human immunodeficiency virus (HIV) 1, with its peptide epitope is characterized by a panel of overlapping peptides, a peptide epitope library and molecular modeling techniques, The sequence CSGKLICTTAVPW, corresponding to amino acids 605-617 of gp41, was identified as the best binding peptide (K-D = 1x10(-8) mol/l), This peptide served as a starting point to prepare a cellulose-bound peptide epitope library in which each residue of the epitope is substituted by all L- and D-amino acids, resulting in 494 epitope peptide variants which were subsequently analyzed for binding 3D6, The library was synthesized to identify residues critical for binding and to obtain information about the molecular environment of the epitope peptide bound to 3D6, Both cysteine residues, as well as isoleucine 6, threonine 8 and proline 12, of the epitope were highly sensitive to substitution, Using the data obtained from the epitope characterization, as well as a low-resolution electron density map of a 3D6 Fab-peptide complex, a 3-D model of the Fab-peptide complex was generated by molecular modeling, The modeling experiments predict binding of the peptide, which is cyclized via the two cysteine residues, to a pocket formed dominantly by the hypervariable loops complementarity determining regions CDR3L, CDR2H and CDR3H. C1 HUMBOLDT UNIV BERLIN,KLINIKUM CHARITE,INST MED IMMUNOL,D-10098 BERLIN,GERMANY. HUMBOLDT UNIV BERLIN,KLINIKUM CHARITE,INST BIOCHEM,D-10098 BERLIN,GERMANY. UNIV WIEN,INST ANGEW MIKROBIOL,A-1190 VIENNA,AUSTRIA. UNIV BATH,DEPT BIOCHEM,BATH BA2 7AY,AVON,ENGLAND. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812. NR 55 TC 24 Z9 25 U1 0 U2 1 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0269-2139 J9 PROTEIN ENG JI Protein Eng. PD MAY PY 1995 VL 8 IS 5 BP 471 EP 479 DI 10.1093/protein/8.5.471 PG 9 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA RN591 UT WOS:A1995RN59100009 PM 8532669 ER PT J AU GLINSKI, RJ NUTH, JA AF GLINSKI, RJ NUTH, JA TI A MOLECULE OF THE FORM CH(2)X MAY BE RESPONSIBLE FOR MANY OF THE DIFFUSE INTERSTELLAR BANDS - A DISCUSSION OF THIOFORMALDEHYDE SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID PYROLYSIS JET SPECTROSCOPY; INTER-STELLAR BANDS; ABSORPTION-SPECTRUM; DARK CLOUDS; CARRIERS; PHOSPHORESCENCE; FEATURES; SYSTEM; IDENTIFICATION; THIOKETENE AB Only recently have groups of diffuse interstellar bands (DIBs) been observed to have regular structure lending new hope for the identification of the bands' origins. Herbig has reported a group of bands between 6770 and 6860 Angstrom which seem to show regular spacing and intensity alternation. We suggest that these bands resemble perpendicular vibronic bands in a molecule of the form CH(2)X. As the Herbig group lies very near an expected transition of similar form in thioformaldehyde, CH2S, an analysis of the absorption spectrum of that molecule was made to determine if it had other bands in common with the DIB spectrum, Six prominent, red-shaded, sharp, single-headed bands were calculated, based on laboratory data, to have absolute frequency positions within 2 cm(-1) of those for the corresponding DIBs. The transitions would originate from the 2 nu(3) level in the ground electronic state of thioformaldehyde, suggesting that vibrationally hot bands in the transition (A) over tilde(1)A(2) < -(X) over tilde(1)A(1), may correspond to a number of DIBs. Although no absorption features are seen from a vibrationally cold ground state, only a few thioformaldehyde bands expected to be more intense than those suggested to be in the DLB spectra have not been observed to date. There are no significant inconsistencies between corresponding thioformaldehyde bands and DIBs with respect to established DIB families. The corresponding bands also generally agree in their shapes and expected intensities. The DIBs appear slightly narrower than the thioformaldehyde bands even if the latter were from a rotationally cold molecule. C1 TENNESSEE TECHNOL UNIV,DEPT CHEM,COOKEVILLE,TN 38505. RP GLINSKI, RJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 691,GREENBELT,MD 20771, USA. RI Nuth, Joseph/E-7085-2012 NR 47 TC 7 Z9 7 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD MAY PY 1995 VL 107 IS 711 BP 453 EP 461 DI 10.1086/133574 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QY228 UT WOS:A1995QY22800006 ER PT J AU HUDSON, RL MOORE, MH AF HUDSON, RL MOORE, MH TI FAR-IR SPECTRAL CHANGES ACCOMPANYING PROTON IRRADIATION OF SOLIDS OF ASTROCHEMICAL INTEREST SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID WATER ICE; OPTICAL-CONSTANTS; LOW-TEMPERATURES; CRYSTALLINE; AMORPHIZATION; MOLECULES AB Far-infrared spectroscopy was used to investigate crystalline-to-amorphous phase changes in irradiated solids. Radiation-induced changes at T less than or equal to 77 K were studied in four solids of astrochemical interest: H2O, CH3OH, H2CO, and CO2. Rates of amorphization were compared for H2O and CH3OH. The behavior of each irradiated sample was observed on subsequent warming. Applications of the data to astronomical problems are given. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTROCHEM BRANCH,GREENBELT,MD 20771. RP HUDSON, RL (reprint author), ECKERD COLL,DEPT CHEM,ST PETERSBURG,FL 33733, USA. RI Hudson, Reggie/E-2335-2012 NR 46 TC 48 Z9 48 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0146-5724 J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD MAY PY 1995 VL 45 IS 5 BP 779 EP 789 DI 10.1016/0969-806X(94)00099-6 PG 11 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA QT580 UT WOS:A1995QT58000016 ER PT J AU WILSON, BD MANNUCCI, AJ EDWARDS, CD AF WILSON, BD MANNUCCI, AJ EDWARDS, CD TI SUBDAILY NORTHERN-HEMISPHERE IONOSPHERIC MAPS USING AN EXTENSIVE NETWORK OF GPS RECEIVERS SO RADIO SCIENCE LA English DT Article; Proceedings Paper CT Ionospheric Effects Symposium (IES 93) CY 1993 CL ALEXANDRIA, VA SP USN, NAVAL RES LAB, PHILLIPS LAB, USA, SPACE & TERRESTRIAL COMMUN DIRECTORATE, USN, OFF NAVAL RES ID SATELLITE AB Ionospheric total electron content (TEC) data derived from dual-frequency Global Positioning System (GPS) signals from 30 globally distributed network sites are fit to a simple ionospheric shell model, yielding a map of the ionosphere in the northern hemisphere every 12 hours during the January 1-15, 1993 period, as well as values for the satellite and receiver instrumental biases. Root-mean-square (RMS) residuals of 2-3 TEC units are observed over the 20 degrees-80 degrees latitude band. Various systematic errors affecting the TEC estimates are discussed. The capability of using these global maps to produce ionospheric calibrations for sites at which no GPS data are available is also investigated. RP WILSON, BD (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Mannucci, Anthony/A-1349-2007 OI Mannucci, Anthony/0000-0003-2391-8490 NR 11 TC 101 Z9 114 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY-JUN PY 1995 VL 30 IS 3 BP 639 EP 648 DI 10.1029/94RS03186 PG 10 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA RB414 UT WOS:A1995RB41400014 ER PT J AU FORNEY, LJ FRALICK, GC AF FORNEY, LJ FRALICK, GC TI 3-WIRE THERMOCOUPLE - FREQUENCY-RESPONSE IN CONSTANT FLOW SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP FORNEY, LJ (reprint author), GEORGIA INST TECHNOL,SCH CHEM ENGN,ATLANTA,GA 30332, USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1995 VL 66 IS 5 BP 3331 EP 3336 DI 10.1063/1.1145503 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA QZ069 UT WOS:A1995QZ06900038 ER PT J AU MOORE, TE DELCOURT, DC AF MOORE, TE DELCOURT, DC TI THE GEOPAUSE SO REVIEWS OF GEOPHYSICS LA English DT Review ID INTERPLANETARY MAGNETIC-FIELD; LATITUDE BOUNDARY-LAYER; PLASMA SHEET BOUNDARY; MAGNETOSPHERIC ELECTRIC-FIELDS; MASS-SPECTROMETER OBSERVATIONS; ION TEMPERATURE ANISOTROPY; SUPERPOSED EPOCH ANALYSIS; SUBSTORM CURRENT WEDGE; EXOS-D OBSERVATIONS; TAIL CURRENT SHEET AB Coupled to the Earth and protected by the geomagnetic field, terrestrial matter in the plasma state dominates a larger region of space than was suspected when the ''space age'' began, a region we refer to as the geosphere. Accelerated and heated by solar wind energy, this matter expands in size and increases in mass density in response to the Sun's ultraviolet spectrum, heliospheric conditions, and the occurrence of severe space storms. Such storms regularly damage spacecraft, interfere with communications, and trigger power grid interruptions or failures. They occur within the geopause region, that is, the volume defined by the limits of the instantaneous boundary between plasmas that are primarily heliospheric and geospheric. The geopause is analogous in some ways to the heliopause but also resembles the terrestrial air-sea interface. It is the boundary layer across which the supersonically expanding solar plasma delivers momentum and energy to the terrestrial plasma and gas, exciting them into motion, ''evaporating'' them into space, and dissipating considerable amounts of power in thermal forms, while generating energetic particles through repeated storage and explosive release of electromagnetic energy. The intensity of the solar wind and the orientation of its magnetic field jointly control the strength of the coupling between solar and terrestrial plasmas and hence the occurrence of severe storms in the geopause region. C1 CTR ETUDES ENVIRONNEMENTS TERR & PLANETAIRES, F-94107 ST MAUR DES FOSSES, FRANCE. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, SPACE PLASMA PHYS BRANCH, HUNTSVILLE, AL 35812 USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 209 TC 70 Z9 70 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 EI 1944-9208 J9 REV GEOPHYS JI Rev. Geophys. PD MAY PY 1995 VL 33 IS 2 BP 175 EP 209 DI 10.1029/95RG00872 PG 35 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RB712 UT WOS:A1995RB71200002 ER PT J AU QUIGLEY, CJ MEAD, J JOHNSON, AR AF QUIGLEY, CJ MEAD, J JOHNSON, AR TI LARGE-STRAIN VISCOELASTIC CONSTITUTIVE MODELS FOR RUBBER .2. DETERMINATION OF MATERIAL CONSTANTS SO RUBBER CHEMISTRY AND TECHNOLOGY LA English DT Article ID BEHAVIOR AB A method for determining material constants in large strain viscoelastic materials was demonstrated for a highly saturated nitrile rubber. Material constant selection was based an viscoelastic stress relaxation data at small and large strains, under both tension and compression, and was constrained to assure Drucker stability. Assuming that the viscoelastic strain energy function was both time and strain separable, a Prony series was constructed for the time dependent material constants. For comparison, four different Prony series were developed from collocation methods and a nonlinear regression analysis, each separately based on either large or small tensile strain relaxation data. III addition, a final Prony series was constructed from dynamic data. These Prony series were included in this comparison to judge their ability to predict both large and small strain material behavior. Finite element analyses of large and small step-strain relaxation tests and a single cycle hysteresis loop at large deformations were performed for each set of Prony series. The results were then compared to experimental behavior. The Prony series based on the constrained method accurately predicted step-strain relaxation behavior at all strain levels, for both tension and compression. The finite element results for the other Prony series show that large strain material behavior was best predicted by those Prony series based on large strain material behavior. Similar findings were found for small strain material behavior. The constrained Prony series and the two large strain based Prony series best modeled the experimental hysteresis loop. C1 NASA,LANGLEY RES CTR,USA,RES LAB,VEHICLE STRUCT DIRECTORATE,HAMPTON,VA 23681. RP QUIGLEY, CJ (reprint author), USA,RES LAB,MAT DIRECTORATE,WATERTOWN,MA 02172, USA. NR 27 TC 16 Z9 16 U1 0 U2 4 PU AMER CHEMICAL SOC INC PI AKRON PA RUBBER DIV UNIV AKRON PO BOX 499, AKRON, OH 44309-0499 SN 0035-9475 J9 RUBBER CHEM TECHNOL JI Rubber Chem. Technol. PD MAY-JUN PY 1995 VL 68 IS 2 BP 230 EP 247 DI 10.5254/1.3538738 PG 18 WC Polymer Science SC Polymer Science GA RG264 UT WOS:A1995RG26400005 ER PT J AU YAMARONE, CA CHRISTENSEN, EJ FU, LL AF YAMARONE, CA CHRISTENSEN, EJ FU, LL TI TOPEX/POSEIDON MISSION - GLOBAL MEASUREMENTS OF SEA-LEVEL AT UNPRECEDENTED ACCURACY SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article AB This paper describes the TOPEX/POSEIDON mission, a joint project between the United States and France with particular emphasis on measurement capabilities and performance. The satellite has provided unprecedented measurements of global sea level since it was launched on 10 August 1992 from Kourou, French Guiana with an Arianespace 42P launch vehicle. TOPEX/POSEIDON is comprised of two microwave radar altimeters, a microwave radiometer, and three precision tracking systems that combine to produce an overall global sea level measurement of less than 5 cm. The accuracy of the measurement is attributed to the design and implementation of: the satellite and its instrument complement, the precision orbit-determination and tracking systems, the ground processing system, and the verification and calibration system. The satellite and measurement systems will be discussed, with an emphasis on the sensors, precision orbit-determination process, and the verification process. In addition, current results provided by TOPEX/POSEIDON science investigators will be summarized. RP YAMARONE, CA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 264-686,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD MAY PY 1995 VL 15 IS 3 BP 133 EP 143 PG 11 WC Engineering, Aerospace SC Engineering GA TJ119 UT WOS:A1995TJ11900002 ER PT J AU BENNETT, GL HEMLER, RJ SCHOCK, A AF BENNETT, GL HEMLER, RJ SCHOCK, A TI DEVELOPMENT AND USE OF THE GALILEO AND ULYSSES POWER SOURCES SO SPACE TECHNOLOGY-INDUSTRIAL AND COMMERCIAL APPLICATIONS LA English DT Article AB The Galileo mission to Jupiter and the Ulysses mission to explore the polar regions of the Sun required a new power source: the general-purpose heat source radioisotope thermoelectric generator (GPHS-RTG), the most powerful RTG yet flown. Four flight-qualified GPHS-RTGs were fabricated with one that is being used on Ulysses, two that are being used on Galileo and one that was a common spare (and is now available for the Cassini mission to Saturn). In addition, an Engineering Unit and a Qualification Unit were fabricated to qualify the design for space through rigorous ground tests. This paper summarizes the ground testing and performance predictions showing that the GPHS-RTGs have met and will continue to meet or exceed the performance requirements of the on-going Galileo and Ulysses missions. C1 NASA,WASHINGTON,DC 20546. 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 0892-9270 J9 SPACE TECHNOL JI Space Tech.-Ind. Comm. Appl. PD MAY PY 1995 VL 15 IS 3 BP 157 EP 174 PG 18 WC Engineering, Aerospace SC Engineering GA TJ119 UT WOS:A1995TJ11900004 ER PT J AU MOORE, TE DELCOURT, DC AF MOORE, TE DELCOURT, DC TI LARGE-SCALE STRUCTURE OF MAGNETOSPHERIC PLASMA SO SURVEYS IN GEOPHYSICS LA English DT Article; Proceedings Paper CT IAGA Division III Report Reviews on Progress in Magnetospheric Physics, 1991-1993, at the 7th Scientific Assembly CY AUG 08-20, 1993 CL BUENOS AIRES, ARGENTINA SP Int Assoc Geomagnetism & Aeron DE MAGNETOSPHERE; PLASMA; STRUCTURE; ENTRY BOUNDARY; GEOPAUSE; REGION-1 VORTICES; LOW-ENERGY LAYER; ADIABACITY BOUNDARY; INJECTION PORT ID MASS-SPECTROMETER OBSERVATIONS; SUPERPOSED EPOCH ANALYSIS; SUBSTORM CURRENT WEDGE; MAGNETIC-FIELD MODEL; SHEET BOUNDARY-LAYER; EXOS-D OBSERVATIONS; ION DISTRIBUTIONS; NEUTRAL SHEET; POLAR WIND; SOLAR-WIND AB Recent investigations of magnetospheric plasma structure are summarized under the broad categories of empirical models, transport across boundaries, formation, and dynamics of the plasma sheet. This report reviews work in these areas during the period 1991 to 1993. Fully three-dimensional empirical models and simulations have become important contributors to our understanding of the magnetospheric system. Some new structural concepts have appeared in the literature: the 'entry boundary' and 'geopause', the plasma sheet 'region 1 vortices', the 'low-energy layer', the 'adiabaticity boundary' or 'wall region', and a region in the tail to which we refer as the 'injection port'. Traditional structural concepts have also been the subject of recent study, notably the plasmapause, the magnetopause, and the plasma sheet. Significant progress has been made in understanding the nature of plasma sheet formation and dynamics, but the acceleration of electrons to high energy remains somewhat mysterious. C1 CTR ETUDES ENVIRONM TERR & PLANETAIRES, F-94107 ST MAUR DES FOSSES, FRANCE. RP NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 84 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-3298 EI 1573-0956 J9 SURV GEOPHYS JI Surv. Geophys. PD MAY PY 1995 VL 16 IS 3 BP 363 EP 387 DI 10.1007/BF01044573 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA RH526 UT WOS:A1995RH52600005 ER PT J AU ELHADY, NM ZANG, TA AF ELHADY, NM ZANG, TA TI LARGE-EDDY SIMULATION OF NONLINEAR EVOLUTION AND BREAKDOWN TO TURBULENCE IN HIGH-SPEED BOUNDARY-LAYERS SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article ID COMPRESSIBLE TURBULENCE; FLOWS; MODEL; STABILITY; VISCOSITY AB The nonlinear evolution and laminar-turbulent breakdown of a boundary-layer flow along a cylinder at Mach 4.5 is investigated with large-eddy temporal simulation. The results are validated using the direct numerical simulation data of Pruett and Zang. The structure of the flow during the transition process is studied in terms of the vorticity field. The subgrid scales are modeled dynamically, where the model coefficients are determined as part of the solution from the local resolved field. In the numerical simulation the dynamic-model coefficients are obtained by using both the strain-rate contraction of Germane et al. and the least-squares contraction of Lilly; they produced some differences in the details of the vorticity structure inside the transition region. A new dynamic model that utilizes the second-order velocity structure function is used to parametrize the small-scale field. The evolution to turbulence is successfully simulated with dynamic subgrid-scale modeling at least in terms of average quantities as well as vorticity fields. This is achieved with one-sixth of the grid resolution used in direct numerical simulation. C1 ANALYT SERV & MAT INC,HAMPTON,VA 23666. NASA,LANGLEY RES CTR,HAMPTON,VA 23681. NR 39 TC 10 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD MAY PY 1995 VL 7 IS 3 BP 217 EP 240 DI 10.1007/BF00312364 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA QY666 UT WOS:A1995QY66600005 ER PT J AU KHAROUK, VI MIDDLETON, EM SPENCER, SL ROCK, BN WILLIAMS, DL AF KHAROUK, VI MIDDLETON, EM SPENCER, SL ROCK, BN WILLIAMS, DL TI ASPEN BARK PHOTOSYNTHESIS AND ITS SIGNIFICANCE TO REMOTE-SENSING AND CARBON BUDGET ESTIMATES IN THE BOREAL ECOSYSTEM SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT International-Boreal-Forest-Research-Association Conference on Boreal Forests and Global Change CY SEP 25-30, 1994 CL SASKATOON, CANADA SP Int Boreal Forest Res Assoc DE BARK PHOTOSYNTHESIS; ASPEN; BOREAS; BARK CHLOROPHYLL AB Aspen bark was investigated for photosynthetic function, pigment content, and spectral characteristics during the 1993-1994 Boreal Ecosystem-Atmosphere Study (BOREAS) summer field campaigns in the boreal zone of Saskatchewan, Canada. Parameters related to photosynthetic function were similar for bark and leaves: chlorophyll (Chl) concentration; fluorescence responses; and spectral reflectance. Similar increases along a vertical gradient from base to tree top were observed for incident photosynthetically active radiation (PAR), photosynthetic pigment content, photosynthetic capacity, and spectral reflectance variables. Since transmittance of aspen bark periderm was 20-30% in the blue, and 50-60% in the red Chl absorption bands, the PAR available to the photosynthetic cortical layer in the natural, canopy environment (<1000 mu mol m(-2) s(-1)) was sufficient to support positive net assimilation (<8-10 mu mol CO2 m(-2) s(-1)) under ideal conditions (e.g., light, temperature, saturating CO2), a rate approximately 30-50% that of leaves. However, the respiring tissues comprising the greater fraction of bark tissue bias the balance of CO2 exchange in favour of respiration for the whole bark. Therefore, net photosynthesis under ambient conditions on the whole bark was, in general, negative. The total bark surface area was estimated to contain 17-40% of the whole tree Chl. The contribution of the bark surface area fraction of the full canopy (leaves plus bark) increased with age (<60 years), with a similar trend expected for bark in total tree (and stand) photosynthesis. A spectral reflectance variable, the red edge inflection point (REIP), was related to total bark Chl content (r(2)=0.74). A better predictive relationship (r(2)=0.82) for total bark Chl was observed using a spectral index calculated from the reflectance ratio of two narrow wavebands (R3/R2: R2 and R3 are between 0.715-0.726 mu m and 0.734-0.747 mu m, respectively), which may have greater utility in landscape remote sensing. The bark spectra for Chl-containing bark should improve understanding of carbon balance in aspen forests, based on landscape-level radiative transfer simulations. C1 NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771. UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,COMPLEX SYST RES CTR,DURHAM,NH 03824. RP KHAROUK, VI (reprint author), RUSSIAN ACAD SCI,SUKACHEV FOREST INST,ACADEMGORODOK,KRASNOYARSK 660036,RUSSIA. NR 24 TC 37 Z9 44 U1 2 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD MAY PY 1995 VL 82 IS 1-2 BP 483 EP 497 DI 10.1007/BF01182858 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA RV439 UT WOS:A1995RV43900049 ER PT J AU MCBEATH, MK SHAFFER, DM KAISER, MK AF MCBEATH, MK SHAFFER, DM KAISER, MK TI HOW BASEBALL OUTFIELDERS DETERMINE WHERE TO RUN TO CATCH FLY BALLS SO SCIENCE LA English DT Article ID FREE-FALL TRAJECTORIES; ACCELERATION; INFORMATION; PERCEPTION; CURVATURE; MOTION AB Current theory proposes that baseball outfielders catch fly balls by selecting a running path to achieve optical acceleration cancellation of the ball. Yet people appear to lack the ability to discriminate accelerations accurately. This study supports the idea that outfielders convert the temporal problem to a spatial one by selecting a running path that maintains a linear optical trajectory (LOT) for the ball. The LOT model is a strategy of maintaining ''control'' over the relative direction of optical ball movement in a manner that is similar to simple predator tracking behavior. C1 NASA,AMES RES CTR,HUMAN & SYST TECHNOL BRANCH,MOFFETT FIELD,CA 94035. RP MCBEATH, MK (reprint author), KENT STATE UNIV,DEPT PSYCHOL,KENT,OH 44242, USA. RI Kato, Takaaki/A-6492-2010 OI Kato, Takaaki/0000-0002-7610-3853 NR 35 TC 193 Z9 194 U1 0 U2 18 PU AMER ASSOC ADVAN SCIENCE PI WASHINGTON PA 1333 H ST NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 28 PY 1995 VL 268 IS 5210 BP 569 EP 573 DI 10.1126/science.7725104 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QV407 UT WOS:A1995QV40700038 PM 7725104 ER PT J AU MILES, JH AF MILES, JH TI A NOTE ON 3-DIMENSIONAL EFFECTS IN SEGMENTATION APPROACH FOR ANALYSIS OF ONE-DIMENSIONAL WAVES IN DUCTS OF VARYING CROSS-SECTIONAL AREA - AUTHORS REPLY SO JOURNAL OF SOUND AND VIBRATION LA English DT Letter ID INCOMPRESSIBLE MEAN FLOW RP MILES, JH (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU ACADEMIC PRESS (LONDON) LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD APR 27 PY 1995 VL 182 IS 2 BP 328 EP 335 DI 10.1006/jsvi.1995.0200 PG 8 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA QV494 UT WOS:A1995QV49400011 ER PT J AU WEISSMAN, P AF WEISSMAN, P TI SOLAR SYSTEM - BODIES ON THE BRINK SO NATURE LA English DT Editorial Material ID COMETS; BELT RP WEISSMAN, P (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 13 TC 1 Z9 2 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD APR 27 PY 1995 VL 374 IS 6525 BP 762 EP 763 DI 10.1038/374762a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QV315 UT WOS:A1995QV31500024 ER PT J AU CHAPMAN, CR VEVERKA, J THOMAS, PC KLAASEN, K BELTON, MJS HARCH, A MCEWEN, A JOHNSON, TV HELFENSTEIN, P DAVIES, ME MERLINE, WJ DENK, T AF CHAPMAN, CR VEVERKA, J THOMAS, PC KLAASEN, K BELTON, MJS HARCH, A MCEWEN, A JOHNSON, TV HELFENSTEIN, P DAVIES, ME MERLINE, WJ DENK, T TI DISCOVERY AND PHYSICAL-PROPERTIES OF DACTYL, A SATELLITE OF ASTEROID 243-IDA SO NATURE LA English DT Article ID FAMILIES AB OBSERVATIONS Of Stellar occultations by asteroids have suggested that some may have satellites(1), But given the absence of any confirmatory evidence, the prevailing view has been that although such satellites probably do exist, they are likely to be rare(2). Here we report the discovery(3) by the Galileo spacecraft of a satellite associated with the asteroid 243 Ida, Although the satellite, Dactyl, is only 1.6 km across, it has been imaged with sufficient resolution for geological analysis, We describe the physical properties of Dactyl, with emphasis on its notably smooth shape, its crater population (which includes a crater chain) and its photometric properties, We find that, spectroscopically, Dactyl resembles both Ida and the other members of the Koronis asteroid family, implying a similar composition; small spectral differences may reflect a space weathering process that slightly alters the colours with time, We argue that Dactyl originated during the breakup of the Koronis parent body, and that satellites could be common around other asteroids (particularly members of asteroid families). C1 CORNELL UNIV,CTR RADIOPHYS & SPACE RES,ITHACA,NY 14853. CALTECH,JET PROP LAB,PASADENA,CA 91109. NATL OPT ASTRON OBSERV,TUCSON,AZ 85719. US GEOL SURVEY,FLAGSTAFF,AZ 86001. RAND CORP,SANTA MONICA,CA 90406. INST PLANETENERKUNDUNG,D-12484 BERLIN,GERMANY. RP CHAPMAN, CR (reprint author), SJI,INST PLANETARY SCI,620 N 6TH AVE,TUCSON,AZ 85705, USA. NR 23 TC 61 Z9 61 U1 0 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD APR 27 PY 1995 VL 374 IS 6525 BP 783 EP 785 DI 10.1038/374783a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QV315 UT WOS:A1995QV31500036 ER PT J AU BELTON, MJS CHAPMAN, CR THOMAS, PC DAVIES, ME GREENBERG, R KLAASEN, K BYRNES, D DAMARIO, L SYNNOTT, S JOHNSON, TV MCEWEN, A MERLINE, WJ DAVIS, DR PETIT, JM STORRS, A VEVERKA, J ZELLNER, B AF BELTON, MJS CHAPMAN, CR THOMAS, PC DAVIES, ME GREENBERG, R KLAASEN, K BYRNES, D DAMARIO, L SYNNOTT, S JOHNSON, TV MCEWEN, A MERLINE, WJ DAVIS, DR PETIT, JM STORRS, A VEVERKA, J ZELLNER, B TI BULK-DENSITY OF ASTEROID 243-IDA FROM THE ORBIT OF ITS SATELLITE DACTYL SO NATURE LA English DT Article ID S-TYPE ASTEROIDS; ORDINARY CHONDRITES AB DURING its reconnaissance of the asteroid 243 Ida, the Galileo spacecraft returned images of a second object, 1993(243)1 Dactyl(1)-the first confirmed satellite of an asteroid. Sufficient data were obtained on the motion of Dactyl to determine its orbit as a function of Ida's mass. Here we apply statistical and dynamical arguments to constrain the range of possible orbits, and hence the mass of Ida. Combined with the volume of Ida(2), this yields a bulk density of 2.6 +/- 0.5 g cm(-3). Allowing for the uncertainty in the porosity of Ida, this density range is consistent with a bulk chondritic composition, and argues against some (but not all) classes of meteoritic igneous rock types that have been suggested as compositionally representative of S-type asteroids like Ida. C1 SAIC,INST PLANETARY SCI,TUCSON,AZ 85705. CORNELL UNIV,CTR RADIOPHYS & SPACE RES,ITHACA,NY 14853. RAND CORP,SANTA MONICA,CA 90406. UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721. CALTECH,JET PROP LAB,PASADENA,CA 91109. US GEOL SURVEY,FLAGSTAFF,AZ 86001. SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. GEORGIA SO UNIV,DEPT PHYS,STATESBORO,GA 30460. RP BELTON, MJS (reprint author), NATL OPT ASTRON OBSERV,TUCSON,AZ 85719, USA. NR 24 TC 98 Z9 98 U1 0 U2 4 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD APR 27 PY 1995 VL 374 IS 6525 BP 785 EP 788 DI 10.1038/374785a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QV315 UT WOS:A1995QV31500037 ER PT J AU MARTIN, TZ AF MARTIN, TZ TI MASS OF DUST IN THE MARTIAN ATMOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS ATMOSPHERE; OPACITY; STORMS AB Estimates of the mass of dust suspended in the Martian atmosphere are derived from global and regional 9-mu m opacity maps produced from Viking Infrared Thermal Mapper data. During the peak of the 1977b storm, a total dust mass of approximately 4.3 x 10(14) g was suspended, equivalent to 4.3 x 10(-4) g/cm(2), or a Layer 1.4 mu m thick. During a local dust storm near Solis Planum at L(s)227 degrees, approximately 1.3 x 10(13) g of dust were lofted, equal to about a 6-mu m layer in that vicinity. RP MARTIN, TZ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 169-237,PASADENA,CA 91109, USA. NR 17 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1995 VL 100 IS E4 BP 7509 EP 7512 DI 10.1029/95JE00414 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA QV150 UT WOS:A1995QV15000003 ER PT J AU BOWEN, BW ABREUGROBOIS, FA BALAZS, GH KAMEZAKI, N LIMPUS, CJ FERL, RJ AF BOWEN, BW ABREUGROBOIS, FA BALAZS, GH KAMEZAKI, N LIMPUS, CJ FERL, RJ TI TRANS-PACIFIC MIGRATIONS OF THE LOGGERHEAD TURTLE (CARETTA-CARETTA) DEMONSTRATED WITH MITOCHONDRIAL-DNA MARKERS SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE CONSERVATION GENETICS; MIXED STOCK ASSESSMENT; MARINE TURTLES AB Juvenile loggerhead turtles (Caretta caretta) have recently been documented in the vicinity of Baja California, and thousands of these animals have been captured in oceanic fisheries of the North Pacific, The presence of loggerhead turtles in the central and eastern North Pacific is a prominent enigma in marine turtle distribution because the nearest documented nesting concentrations for this species are in Australia and Japan, over 10,000 km from Baja California. To determine the origin of the Baja California feeding aggregate and North Pacific fishery mortalities, samples from nesting areas and pelagic feeding aggregates were compared with genetic markers derived from mtDNA control region sequences, Overall, 57 of 60 pelagic samples (95%) match haplotypes seen only in Japanese nesting areas, implicating Japan as the primary source of turtles in the North Pacific Current and around Baja California. Australian nesting colonies may contribute the remaining 5% of these pelagic feeding aggregates. Juvenile loggerhead turtles apparently traverse the entire Pacific Ocean, approximately one-third of the planet, in the course of developmental migrations, but mortality in high-seas fisheries raises concern over the future of this migratory population. C1 UNIV FLORIDA,DEPT HORT SCI,PROGRAM PLANT MOLEC & CELLULAR BIOL,GAINESVILLE,FL 32611. INST CIENCIAS MAR & LIMNOL,ESTAC MAZARTLAN,MAZATLAN 82000,SINALOA,MEXICO. NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES SCI CTR,HONOLULU LAB,HONOLULU,HI 96822. KYOTO UNIV,GRAD SCH HUMAN & ENVIRONM STUDIES,SAKYO KU,KYOTO 606,JAPAN. QUEENSLAND DEPT ENVIRONM & HERITAGE,BRISBANE,QLD 4002,AUSTRALIA. RP BOWEN, BW (reprint author), UNIV FLORIDA,GENET ANAL CORE,POB 110699,GAINESVILLE,FL 32611, USA. NR 40 TC 139 Z9 146 U1 3 U2 22 PU NATL ACAD SCIENCES 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 25 PY 1995 VL 92 IS 9 BP 3731 EP 3734 DI 10.1073/pnas.92.9.3731 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA QV930 UT WOS:A1995QV93000020 PM 7731974 ER PT J AU GRIVET-TALOCIA, S AF GRIVET-TALOCIA, S TI ON THE SCALE DEPENDENCE OF FRACTAL DIMENSION FOR BAND-LIMITED 1/F(ALPHA) NOISE SO PHYSICS LETTERS A LA English DT Article AB An analytic approach for the evaluation of the fractal dimension is presented and applied to band-limited 1/f(alpha) noise. High and low cutoff frequencies are shown to affect the scaling exponent, which is time-scale dependent. Asymptotic expansions of the fractal dimension are derived and compared to numerical estimations. C1 SCI SYST & APPLICAT INC, LANHAM, MD 20706 USA. RP GRIVET-TALOCIA, S (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 912, GREENBELT, MD 20771 USA. RI Grivet-Talocia, Stefano/M-1480-2015 OI Grivet-Talocia, Stefano/0000-0002-5463-3810 NR 17 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD APR 24 PY 1995 VL 200 IS 3-4 BP 264 EP 276 DI 10.1016/0375-9601(95)00180-B PG 13 WC Physics, Multidisciplinary SC Physics GA QV086 UT WOS:A1995QV08600008 ER PT J AU BEAVIS, D BENNETT, MJ CARROLL, JB CHIBA, J CHIKANIAN, A CRAWFORD, HJ CRONQVIST, M DARDENNE, Y DEBBE, R DOKE, T ENGELAGE, J FLORES, I GREINER, L HAYANO, RS HALLMAN, TJ HECKMAN, HH KASHIWAGI, T KIKUCHI, J KUMAR, BS KUO, C LINDSTROM, PJ MITCHELL, JW NAGAMIYA, S NAGLE, JL POPE, JK STANKUS, P TANAKA, KH WELSH, RC ZHAN, W AF BEAVIS, D BENNETT, MJ CARROLL, JB CHIBA, J CHIKANIAN, A CRAWFORD, HJ CRONQVIST, M DARDENNE, Y DEBBE, R DOKE, T ENGELAGE, J FLORES, I GREINER, L HAYANO, RS HALLMAN, TJ HECKMAN, HH KASHIWAGI, T KIKUCHI, J KUMAR, BS KUO, C LINDSTROM, PJ MITCHELL, JW NAGAMIYA, S NAGLE, JL POPE, JK STANKUS, P TANAKA, KH WELSH, RC ZHAN, W TI HIGH-RATE MULTIPLICITY DETECTOR FOR RELATIVISTIC HEAVY-ION COLLISIONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID TRANSVERSE ENERGY; GEV/C AB We have constructed and operated a detector to measure the multiplicity of secondary particles produced in nucleus-nucleus collisions in the E878 experiment at the Brookhaven National Laboratory AGS facility. We describe the operation and performance of the detector in a high rate Au beam environment, and interpret the multiplicity data in terms of the impact parameters of the nucleus-nucleus collisions. C1 YALE UNIV,AW WRIGHT NUCL STRUCT LAB,NEW HAVEN,CT 06511. BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV CALIF LOS ANGELES,LOS ANGELES,CA. KEK,TSUKUBA,IBARAKI,JAPAN. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. WASEDA UNIV,SCI & INGN RES INST,TOKYO,JAPAN. UNIV TOKYO,TOKYO,JAPAN. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA. UNIV SPACE RES ASSOC,GODDARD SPACE FLIGHT CTR,GREENBELT,MD. COLUMBIA UNIV,NEVIS LAB,IRVINGTON,NY. JOHNS HOPKINS UNIV,BALTIMORE,MD. RI Hayano, Ryugo/F-7889-2012; Kuo, Chaincy/H-9475-2016 OI Hayano, Ryugo/0000-0002-1214-7806; Kuo, Chaincy/0000-0001-7958-8764 NR 14 TC 5 Z9 5 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 APR 21 PY 1995 VL 357 IS 2-3 BP 283 EP 291 DI 10.1016/0168-9002(94)01703-4 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA QV408 UT WOS:A1995QV40800012 ER PT J AU SKINNER, GK BALTHAZOR, RL HERRING, JRH RIDEOUT, RM TUELLER, J BARTHELMY, SD BARTLETT, LM AF SKINNER, GK BALTHAZOR, RL HERRING, JRH RIDEOUT, RM TUELLER, J BARTHELMY, SD BARTLETT, LM TI A BALLOON FLIGHT TEST OF A CODED-MASK TELESCOPE WITH A MULTIELEMENT GERMANIUM DETECTOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID GAMMA-RAY SPECTROSCOPY; NEUTRON; DESIGN; ARRAYS; ORBIT AB The use of a small array of germanium detectors to obtain high spectral resolution X-ray and gamma-ray images of astronomical objects has been demonstrated with a coded mask telescope flown as a piggy-back instrument on the NASA GRIS balloon payload. The design of the experimental telescope is discussed and images of the Crab nebula and of Cygnus X-1 obtained during the flight are presented. The quality of the images is shown to be very close to that expected from simulations. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP SKINNER, GK (reprint author), UNIV BIRMINGHAM,SCH PHYS & SPACE RES,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. RI Tueller, Jack/D-5334-2012; Barthelmy, Scott/D-2943-2012; OI Balthazor, Richard/0000-0002-4568-7446 NR 32 TC 5 Z9 5 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 APR 21 PY 1995 VL 357 IS 2-3 BP 580 EP 587 DI 10.1016/0168-9002(94)01521-X PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA QV408 UT WOS:A1995QV40800045 ER PT J AU CORBET, RHD SMALE, AP OZAKI, M KOYAMA, K IWASAWA, K AF CORBET, RHD SMALE, AP OZAKI, M KOYAMA, K IWASAWA, K TI THE SPECTRUM AND PULSES OF 1E-2259+586 FROM ASCA AND BBXRT OBSERVATIONS SO ASTROPHYSICAL JOURNAL LA English DT Article DE BINARIES, CLOSE; STARS, INDIVIDUAL (1E 2259 + 586); STARS, NEUTRON; X-RAYS, STARS ID SUPERNOVA REMNANT G109.1-1.0; RAY; PERIOD; EXTRAORDINARY; 1E2259+586 AB The 7 s X-ray pulsator 1E 2259+586 was observed for approximately 1 day in 1993 with ASCA. Observations were also obtained with BBXRT in 1990 a few months after Ginga had observed 1E 2259+586 to be brighter than normal and the BBXRT data show 1E 2259+586 to be at an intermediate brightness level. By contrast, the ASCA data appear to have been obtained during a more common lower luminosity state. The pulse profiles we obtain are consistent with a connection between flux and pulse shape reported from Ginga data, and the pulsator continues to spin down. We use our high spectral resolution data to search for cyclotron lines in the spectrum that were claimed from observations made with other satellites. W, find that the ASCA spectra of 1E 2259+586 cannot be satisfactorily fitted with either a single power law or a combination of two power laws, and that significant residuals occur around 1.5 and 5 keV. However, a combination of a power law and a blackbody gives a good fit over the entire ASCA energy band with no evidence of spectral features. We have reanalyzed a Ginga LAC spectrum and find that this is also significantly better fitted by this two-component spectrum than a single power law. A possible explanation for such a two-component spectrum is that the blackbody emission comes from a neutron star and that the power-law component comes, at least in part, from a surrounding nebula. As there has, so far, been no direct evidence that 1E 2259+586 is a binary system we consider whether there are other plausible mechanisms that might power the observed X-ray emission. C1 KYOTO UNIV, DEPT PHYS, SAKYO KU, KYOTO 60601, JAPAN. NAGOYA UNIV, DEPT ASTROPHYS, CHIKUSA KU, NAGOYA, AICHI 46401, JAPAN. PENN STATE UNIV, DEPT ASTRON & ASTROPHYS, DAVEY LAB 525, UNIVERSITY PK, PA 16802 USA. RP CORBET, RHD (reprint author), NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, CODE 666, GREENBELT, MD 20771 USA. RI Ozaki, Masanobu/K-1165-2013 NR 26 TC 73 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 APR 20 PY 1995 VL 443 IS 2 BP 786 EP 794 DI 10.1086/175568 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU584 UT WOS:A1995QU58400028 ER PT J AU BACHMANN, KT DUVALL, TL HARVEY, JW HILL, F AF BACHMANN, KT DUVALL, TL HARVEY, JW HILL, F TI MEASUREMENT OF HIGH-DEGREE SOLAR OSCILLATION FREQUENCIES SO ASTROPHYSICAL JOURNAL LA English DT Article DE SUN, OSCILLATIONS ID MODE AB We present m-averaged solar p- and f-mode oscillation frequencies over the frequency range 1.8 < nu < 5.0 mHz and the spherical harmonic degree range 100 less than or equal to l less than or equal to 1200 from full-disk, 1000 x 1024 pixel, Ca II intensity images collected 1993 June 22-25 with a temporal cadence of 60 s. We itemize the sources and magnitudes of statistical and systematic uncertainties and of small frequency corrections, and we show that our frequencies represent an improvement in accuracy and coverage over previous measurements. Our frequencies agree at the 2 mu Hz level with Mount Wilson frequencies determined for l less than or equal to 600 from full-disk images, and we find systematic offsets of 10-20 mu Hz with respect to frequencies measured from Big Bear and La Palma observations. We give evidence that these latter offsets are indicative of spatial scaling uncertainties associated with the analysis of partial-disk images. In comparison with theory, our p-mode frequencies agree within 10 mu Hz of frequencies predicted by the Los Alamos model but are as much as 100 mu Hz smaller than frequencies predicted by the Denmark and Yale models at degrees near 1000. We also find systematic differences between our n=0 frequencies and the frequencies closely agreed upon by all three models. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP BACHMANN, KT (reprint author), NATL OPT ASTRON OBSERV,NATL SOLAR OBSERV,POB 26732,TUCSON,AZ 85726, USA. RI Duvall, Thomas/C-9998-2012 NR 19 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 APR 20 PY 1995 VL 443 IS 2 BP 837 EP 842 DI 10.1086/175573 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU584 UT WOS:A1995QU58400033 ER PT J AU GUNDERSEN, JO LIM, M STAREN, J WUENSCHE, CA FIGUEIREDO, N GAIER, TC KOCH, T MEINHOLD, PR SEIFFERT, MD COOK, G SEGALE, A LUBIN, PM AF GUNDERSEN, JO LIM, M STAREN, J WUENSCHE, CA FIGUEIREDO, N GAIER, TC KOCH, T MEINHOLD, PR SEIFFERT, MD COOK, G SEGALE, A LUBIN, PM TI DEGREE-SCALE ANISOTROPY IN THE COSMIC MICROWAVE BACKGROUND - SP94 RESULTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC MICROWAVE BACKGROUND; COSMOLOGY, OBSERVATIONS ID DEGREE ANGULAR SCALES; RADIATION AB We present results from two observations of the cosmic microwave background (CMB) performed from the South Pole during the 1993-1994 austral summer. Each observation employed a 3 degrees peak-to-peak sinusoidal, single-difference chop and consisted of a 20 degrees x 1 degrees strip on the sky. The first observation used a receiver which operates in three channels between 38 and 45 GHz (Q-band) with a FWHM beam which varies from 1 degrees to 1.degrees 15. The second observation overlapped the first observation and used a receiver which operates in four channels between 26 and 36 GHz (Ka-band) with a FWHM beam which varies from 1.degrees 5 to 1.degrees 7. Significant correlated structure is observed in all channels for each observation. The spectrum of the structure is consistent with a CMB spectrum and is formally inconsistent with diffuse synchrotron and free-free emission at the 5 sigma level. The amplitude of the structure is inconsistent with 20 K interstellar dust; however, the data do not discriminate against flat or inverted spectrum point sources. The root mean square amplitude (+/- 1 sigma) of the combined (Ka + Q) data is Delta T-rms = 41.2(-6.7)(+15.5) mu K for an average window function which has a peak value of 0.97 at l = 68 and drops to e(-0.5) of the peak value at l = 36 and l = 106. A band power estimate of the CMB power spectrum, C-l, gives [C-l(l)(l + 1)/(2 pi)](B) = 1.77(-0.54)(+1.58) x 10(-10). C1 UNIV CALIF BERKELEY,NSF,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. INST NACL PESQUISAS ESPACIAIS,MCT,DIV ASTROPHYS,BR-12227010 S JOSE CAMPOS,SP,BRAZIL. ESCOLA FED ENGN ITAJUBA,DEPT QUIM FIS,BR-37500000 ITAJUBA,MG,BRAZIL. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP GUNDERSEN, JO (reprint author), UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106, USA. RI Figueiredo, Newton/F-9976-2011 NR 22 TC 85 Z9 84 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 20 PY 1995 VL 443 IS 2 BP L57 EP L60 DI 10.1086/187835 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA QU585 UT WOS:A1995QU58500002 ER PT J AU ACKERMAN, AS TOON, OB HOBBS, PV AF ACKERMAN, AS TOON, OB HOBBS, PV TI NUMERICAL MODELING OF SHIP TRACKS PRODUCED BY INJECTIONS OF CLOUD CONDENSATION NUCLEI INTO MARINE STRATIFORM CLOUDS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BOUNDARY-LAYER; STRATOCUMULUS; ATMOSPHERES; SCATTERING; AEROSOLS; DYNAMICS; TRAILS AB Ship tracks are long-lived, lineal regions of enhanced reflectivity in low-lying marine clouds that appear in satellite imagery downwind of ships. Ship tracks were first observed as cloud lines in visible satellite imagery (type 1), A second (and more common) type of ship track (type 2), which is masked at visible wavelengths by natural variability in cloud reflectivity, is seen at near-infrared wavelengths in satellite imagery. A one-dimensional numerical model is used to simulate measurements of both types of ship tracks and to investigate interactions between aerosol and cloud microphysics, radiative transfer, and turbulent mixing in the cloud-topped marine boundary layer that lead to the formation and provide for the persistence of ship tracks. We find that cloud condensation nuclei (CCN) injections can account for many of the observed properties of ship tracks. Higher CCN concentrations produce increased droplet concentrations, which enhance cloud reflectivity by reducing droplet radius and increasing droplet cross-sectional area. The smaller droplets also reduce the drizzle rate, which can allow cloud water to increase under some conditions, thereby leading to higher cloud reflectivity. However, smaller droplets also evaporate more readily below cloud base. Increased evaporation reduces mixing between the cloud and the subcloud layers during daytime, which causes a decrease in cloud water. The distinction between the two types of ship tracks is suggested to be due to differences in ambient concentrations of CCN that cause variations in turbulent mixing in the boundary layer, through the effect of cloud droplet concentrations on cloud-top longwave radiative cooling. The model predicts lifetimes of > 1 day and > 2 days for the simulated type 1 and type 2 ship tracks, respectively. In the atmosphere, processes not treated in the model, such as horizontal dispersion and changes in large-scale atmospheric conditions, may limit ship track lifetimes. C1 NASA, AMES RES CTR, DIV SPACE SCI, MOFFETT FIELD, CA 94035 USA. RP ACKERMAN, AS (reprint author), UNIV WASHINGTON, DEPT ATMOSPHER SCI, AK-40, SEATTLE, WA 98195 USA. RI Ackerman, Andrew/D-4433-2012 OI Ackerman, Andrew/0000-0003-0254-6253 NR 29 TC 38 Z9 38 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 1995 VL 100 IS D4 BP 7121 EP 7133 DI 10.1029/95JD00026 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800004 ER PT J AU WU, MLC LAU, KM AF WU, MLC LAU, KM TI ATMOSPHERIC BRANCH OF THE GLOBAL HYDROLOGIC-CYCLE IN THE GODDARD-LABORATORY-FOR-ATMOSPHERES INTERACTIVE FORECAST RETRIEVAL ANALYSIS SYSTEM SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MICROWAVE RADIOMETRIC MEASUREMENTS; OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; WATER-VAPOR; TROPICAL PACIFIC; INTRASEASONAL OSCILLATIONS; SOUNDING DATA; HIRS2 MSU; SATELLITE; PRECIPITATION AB In this paper, we present a description of the atmospheric branch of the hydrologic cycle (AHC) in the Goddard Laboratory for Atmospheres interactive forecast retrieval analysis (IFRA) system. Global hydrologic parameters are estimated using a mix of satellite-retrieved geophysical parameters and general circulation model gridded wind fields. The global distribution of components of the AHC and their related fields such as the total precipitable water, rainfall estimate, latent heat flux/evaporation over the ocean, moisture transport, and associated seasonal and low-frequency variability (timescale greater than or equal to 10 days) are studied. Results show that the seasonal variations of these variables are consistent with climatological observations. Positive surface hydrologic forcing (E - P > 0) is found over extended regions in the subtropics and in the oceanic upwelling regions, while negative surface hydrologic forcing (E - P < 0) is concentrated in small regions of heavy precipitation over warm water. Moisture is transported from the regions of positive E - P (evaporation-precipitation) toward regions of negative E - P. The moisture recycling timescale is much larger in the former compared with the latter. On the large scale, rainfall and moisture convergence are highly correlated. Also presented is an analysis of the IFRA tropical rainfall variability. Principal modes of tropical rainfall variation can be identified with the well-known intraseasonal or 30- to 60-day oscillations. Regional characteristics of these oscillations and relationship with other components of the atmospheric hydrologic cycle are investigated. The analysis reveals clearly a premoistening of the tropical atmosphere approximately 10 days prior to enhanced convection over the western Pacific followed by drying out of equatorial central and eastern Pacific. Results show that much of the variability of rainfall in the maritime continent associated with the 30- to 60-day oscillation can be connected with the zonal transport of moisture from the Indian Ocean and the eastern Pacific associated with Walker-type circulation anomalies. The water budget of the tropical western Pacific is strongly influenced by rainfall variability associated with these intraseasonal oscillations. RP WU, MLC (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ATMOSPHERES LAB, GREENBELT, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 41 TC 1 Z9 1 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 APR 20 PY 1995 VL 100 IS D4 BP 7161 EP 7177 DI 10.1029/94JD02959 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800007 ER PT J AU BLAKE, DF KATO, K AF BLAKE, DF KATO, K TI LATITUDINAL DISTRIBUTION OF BLACK CARBON SOOT IN THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EL-CHICHON; AEROSOLS; PARTICLES; CLIMATE; CLOUD; TRANSPORT; ALASKA; SMOKE; HAZE AB Black carbon soot from the upper troposphere and lower stratosphere has been systematically collected at latitudes from 90 degrees N to 45 degrees S. The measured latitudinal distribution of this soot at 10- to 11-km altitude is found to covary with commercial air traffic fuel use, suggesting that aircraft fuel combustion at altitude is the principal source. In addition, at latitudes where the commercial air traffic is high, measured black carbon soot values are high even at 20-km altitude, suggesting that aircraft-generated soot injected just above the tropopause may be transported to higher altitudes. During the volcanically influenced period in which these samples were collected, the number abundances, total mass, and calculated total surface area of black carbon soot are 2-3 orders of magnitude lower than similar measures of sulfuric acid aerosol. During volcanically quiescent periods, the calculated total surface area of black carbon soot aerosol is of the same order of magnitude as that of the background sulfuric acid aerosol. It appears from this comparison that black carbon soot is only capable of influencing lower stratosphere or upper troposphere chemistry during periods when the aerosol budget is not dominated by volcanic activity. It remains to determine the extent to which black carbon soot particles act as nuclei for sulfuric acid aerosol formation. However, mass balance calculations suggest that aircraft soot injected at altitude does not represent a significant source of condensation nuclei for sulfuric acid aerosols. C1 SETI INST, MT VIEW, CA USA. RP BLAKE, DF (reprint author), NASA, AMES RES CTR, PLANETARY BIOL BRANCH, MAILSTOP 239-4, MOFFETT FIELD, CA 94035 USA. NR 29 TC 120 Z9 124 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 1995 VL 100 IS D4 BP 7195 EP 7202 DI 10.1029/94JD03118 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800009 ER PT J AU FRIEDLINGSTEIN, P PRENTICE, KC FUNG, IY JOHN, JG BRASSEUR, GP AF FRIEDLINGSTEIN, P PRENTICE, KC FUNG, IY JOHN, JG BRASSEUR, GP TI CARBON-BIOSPHERE-CLIMATE INTERACTIONS IN THE LAST GLACIAL MAXIMUM CLIMATE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MODEL; VEGETATION; STORAGE; SENSITIVITY; CIRCULATION; CO2 AB The total carbon inventory in the terrestrial biosphere in the last glacial maximum (LGM), 18 kyr ago, is analyzed in a series of experiments that examine the sensitivity of the inventory to vegetation distribution and carbon dynamics. The results show that for most forest vegetation types, carbon densities for the LGM are within 10% of their present-day values. Discrepancies between vegetation distributions simulated by two bioclimatic schemes are attributable to the assignation of vegetation types to climates with rare or no present-day analog. The model experiments, combined with palynogical data for regions with no present-day analog climate, yield to a decrease of 612 +/- 105 Gt C compared to present day. C1 NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. RP FRIEDLINGSTEIN, P (reprint author), BELGIAN INST SPACE AERON, 3 AV CIRCULAIRE, B-1180 BRUSSELS, BELGIUM. RI John, Jasmin/F-8194-2012; Friedlingstein, Pierre/H-2700-2014 OI John, Jasmin/0000-0003-2696-277X; NR 47 TC 29 Z9 30 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 APR 20 PY 1995 VL 100 IS D4 BP 7203 EP 7221 DI 10.1029/94JD02948 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800010 ER PT J AU ZHAO, JX TURCO, RP TOON, OB AF ZHAO, JX TURCO, RP TOON, OB TI A MODEL SIMULATION OF PINATUBO VOLCANIC AEROSOLS IN THE STRATOSPHERE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MT-PINATUBO; EL-CHICHON; ERUPTION CLOUDS; SIZE; SO2; EVOLUTION; TRACKING; LARAMIE; ANALOGS; SUMMER AB A one-dimensional, time-dependent model is used to study the chemical, microphysical, and radiative properties of volcanic aerosols produced by the Mount Pinatubo eruption on June 15, 1991. Our model treats gas-phase sulfur photochemistry, gas-to-particle conversion of sulfur, and the microphysics of sulfate aerosols and ash particles under stratospheric conditions. The dilution and diffusion of the volcanic eruption clouds are also accounted for in these conditions. Heteromolecular homogeneous and heterogeneous binary H2SO4/H2O nucleation, acid and water condensational growth, coagulation, and gravitational sedimentation are treated in detail in the model. Simulations suggested that after several weeks, the volcanic cloud was composed mainly of sulfuric acid/water droplets produced in situ from the SO2 emissions. The large amounts of SO2 (around 20 Mt) injected into the stratosphere by the Pinatubo eruption initiated homogeneous nucleation which generated a high concentration of small H2SO4/H2O droplets. These newly formed particles grew rapidly by condensation and coagulation in the first few months and then reach their stabilized sizes with effective radii in a range between 0.3 and 0.5 mu m approximately one-half year after the eruption. The predicted volcanic cloud parameters reasonably agree with measurements in term of the vertical distribution and lifetime of the volcanic aerosols, their basic microphysical structures (e.g., size distribution, concentration, mass ratio, and surface area) and radiative properties. The persistent volcanic aerosols can produce significant anomalies in the radiation field, which have important climatic consequences. The large enhancement in aerosol surface area can result in measurable global stratospheric ozone depletion. C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. UNIV CALIF LOS ANGELES, DEPT ATMOSPHER SCI, LOS ANGELES, CA 90024 USA. RP ZHAO, JX (reprint author), UNIV HAWAII, SCH OCEAN & EARTH SCI & TECHNOL, DEPT METEOROL, HONOLULU, HI 96822 USA. NR 57 TC 46 Z9 47 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 APR 20 PY 1995 VL 100 IS D4 BP 7315 EP 7328 DI 10.1029/94JD03325 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800020 ER PT J AU HOLLANDSWORTH, SM BOWMAN, KP MCPETERS, RD AF HOLLANDSWORTH, SM BOWMAN, KP MCPETERS, RD TI OBSERVATIONAL STUDY OF THE QUASI-BIENNIAL OSCILLATION IN OZONE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTERANNUAL VARIABILITY; LOWER STRATOSPHERE; DIMENSIONAL MODEL; ANTARCTIC OZONE; BUV DATA; CYCLE; CIRCULATION; MODULATION; WINDS AB The structures of the quasi-biennial oscillations (QBOs) in zonal wind, temperature, and layer ozone amounts are investigated using 11.5 years (January 1979 to June 1990) of National Meteorological Center (NMC) global geopotential height data and global ozone data from the solar backscatter ultraviolet spectrometer (SBUV) on Nimbus 7. The QBO signals are isolated by computing lagged correlations between the deseasonalized, detrended variable fields and a reference signal representative of the equatorial QBO. Lagged correlations are calculated for the full time series and for each season separately to determine seasonal effects. The results depict an equatorial zonal wind QBO in good agreement with the observed QBO in groundbased equatorial zonal wind measurements, although the amplitude of the derived QBO in the NMC data is similar to 30% too weak. The vertical extent of the oscillation is significantly higher (2 mbar) than that previously reported. The temperature QBO is consistent with ground-based observations in the lower stratosphere but weakens with height above similar to 50 mbar. The ozone QBO is strong at all levels from 5 mbar into the lower stratosphere. Though the annual average total ozone QBO is quite symmetric about the equator, the oscillation is highly variable from layer to layer. The phase of the ozone QBO near the equator is consistent with that of the zonal wind and temperature in the middle and upper stratosphere, but the vertical resolution of the SBUV data in the lower stratosphere is too low to accurately represent the vertical phase of the ozone QBO in this region. Subtropical temperature and total ozone anomalies are found to be dependent on season. C1 TEXAS A&M UNIV, DEPT METEOROL, COLLEGE STN, TX 77842 USA. UNIV ILLINOIS, DEPT ATMOSPHER SCI, URBANA, IL 61801 USA. RP HOLLANDSWORTH, SM (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 616, GREENBELT, MD 20771 USA. RI Bowman, Kenneth/A-1345-2012; McPeters, Richard/G-4955-2013 OI Bowman, Kenneth/0000-0002-2667-8632; McPeters, Richard/0000-0002-8926-8462 NR 50 TC 31 Z9 31 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 1995 VL 100 IS D4 BP 7347 EP 7361 DI 10.1029/95JD00193 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800023 ER PT J AU RIND, D LONERGAN, P AF RIND, D LONERGAN, P TI MODELED IMPACTS OF STRATOSPHERIC OZONE AND WATER-VAPOR PERTURBATIONS WITH IMPLICATIONS FOR HIGH-SPEED CIVIL TRANSPORT AIRCRAFT SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE ATMOSPHERE MODEL; TROPOSPHERIC OZONE; CLIMATE CHANGE; EMISSIONS AB Ozone and water vapor perturbations are explored in a series of experiments with the Goddard Institute for Space Studies climate/middle atmosphere model. Large perturbations to stratospheric ozone and water vapor are investigated, with and without allowing sea surface temperatures to change, to illuminate the nature of the dynamic and climatic impact. Then more realistic ozone and water vapor perturbations, similar to those estimated to result from aircraft emissions, are input and the equilibrium response obtained. Removing ozone in the lower stratosphere without allowing sea surface temperatures to change results in in situ cooling of up to 10 degrees C in the tropical lower stratosphere, with radiative warming about half as large in the middle stratosphere. The temperature changes induce increases in tropospheric and lower stratospheric eddy energy and in the lower stratosphere residual circulation of the order of 10%. When sea surface temperatures are allowed to respond to this forcing, the global, annual-average surface air temperature cools by about 1 degrees C as a result of the decreased ozone greenhouse capacity, reduced tropospheric water vapor, and increased cloud cover. For more realistic ozone changes, as defined in the High-Speed Research Program/Atmospheric Effects of Stratospheric Aircraft reports, the stratosphere generally cools by a few tenths degrees Celsius. In this case, the surface air temperature change is not significant, due to the conflicting influences of stratospheric ozone reduction and tropospheric ozone increase, although high-latitude cooling of close to 0.5 degrees C does occur consistently. Doubled stratospheric water vapor cools the middle atmosphere by 2 degrees-3 degrees C and warms the upper troposphere by 0.5 degrees C. Reduced tropospheric-stratospheric vertical stability leads to tropospheric planetary longwave energy increases of some 15% for the longest waves and stratospheric residual circulation increases of 5%. When sea surface temperatures are allowed to change, the surface air temperature warms by just a few tenths of a degree Celsius; although this change is not significant in terms of the model's natural variability, the experiment is warmer than the control in most years. The response is muted as the high altitude of energy input minimizes surface level feedbacks, and high-level cloud cover is reduced. With a more realistic increase of stratospheric water vapor of 7%, the middle atmosphere cools by 0.5 degrees C or less, and the surface temperature change is neither significant nor consistent. Overall, the experiments emphasize that stratospheric changes affect tropospheric dynamics in the model, that tropospheric changes can affect stratospheric dynamics, and that tropospheric feedback processes and natural variability are important when assessing the climatic response to aircraft emissions. RP RIND, D (reprint author), NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, 2880 BROADWAY, NEW YORK, NY 10025 USA. NR 21 TC 43 Z9 44 U1 1 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 APR 20 PY 1995 VL 100 IS D4 BP 7381 EP 7396 DI 10.1029/95JD00196 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA QV028 UT WOS:A1995QV02800025 ER PT J AU RICCA, A BAUSCHLICHER, CW AF RICCA, A BAUSCHLICHER, CW TI THEORETICAL-STUDY OF FE(CO)(N)(-) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ION PHOTOELECTRON-SPECTROSCOPY; COLLISION-INDUCED DISSOCIATION; COUPLED-CLUSTER THEORY; GAUSSIAN-BASIS SETS; MOLECULAR CALCULATIONS; ELECTRON CORRELATION; WAVE-FUNCTIONS; ATOMS; ENERGIES; EXCHANGE AB The structures and CO binding energies are computed for Fe(CO)(n)(-) using a hybrid density functional theory (DFT) approach. The structures and ground states can be explained in terms of maximizing the Fe to CO 2 pi* donation and minimizing Fe-CO 5 sigma repulsion. The trends in the CO binding energies for Fe(CO)(n)(-) and the differences between the trends for Fe(CO)(n)(-) and Fe(CO)(n) are also explained. For Fe(CO)(n)(-), the second, third, and fourth CO bonding energies are in good agreement with experiment, while the first is too small. The first CO binding is also too small using the coupled cluster singles and doubles approach including a perturbational estimate of the connected triple excitations. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. NR 33 TC 51 Z9 51 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA PO BOX 57136, WASHINGTON, DC 20037-0136 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD APR 20 PY 1995 VL 99 IS 16 BP 5922 EP 5926 DI 10.1021/j100016a029 PG 5 WC Chemistry, Physical SC Chemistry GA QU828 UT WOS:A1995QU82800029 ER EF