FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Cabrol, NA Grin, EA Dawidowicz, G AF Cabrol, NA Grin, EA Dawidowicz, G TI A model of outflow generation by hydrothermal underpressure drainage in volcano-tectonic environment, Shalbatana Vallis (Mars) SO ICARUS LA English DT Article ID THARSIS REGION; WRINKLE RIDGES; ORIGIN; EVOLUTION; MARINERIS; CHANNELS; VALLEYS; CYCLE AB The survey of the Shalbatana Vallis course and the analysis of the distribution of the concentric peripheral and radial systems of faults east of Tharsis allow us to propose a model that demonstrates the effect of volcano-tectonic strains generating crossing fault systems where heat points allowed hydrothermal drainage of confined aquifers and generated headwater systems. This model is qualitatively consistent with the strain of the spherical buldge of Tharsis expressed by extensional faults intersected by radial faults in the upper lithosphere. The southward course of the channel is oriented parallel to extensional faults that are related to the wrinkle ridge field of Lunae Planum. The channel is perpendicular to the normal radial faults of eastern Tharsis between the equator and -20 degrees lat. The intersection of these two fault systems generated weak points where magmatic material originating from the lithosphere entered the upper crust through the self-sealing ice-saturated cryosphere. We demonstrate that the system of fault intersections can explain: (a) the hydrothermal drainage of underground aquifers by convective heat flux and dike intrusion that formed chaotic terrains where source areas were generated beneath the cryosphere and (b) the linear course of the sharp-rimmed, U-shaped Shalbatana Vallis intersected by successive chaos developments as governed by the underlying peripheral fault system, The physics of thermal underpressure vapor diffusion and the condensation into water is described as the exchange of heat between the magmatic intrusion and the ice-rich confined layers beneath the chaotic terrains. (C) 1997 Academic Press. C1 UNIV PARIS 01,F-75231 PARIS 05,FRANCE. RP Cabrol, NA (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-3,MOFFETT FIELD,CA 94035, USA. NR 33 TC 29 Z9 29 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 1997 VL 125 IS 2 BP 455 EP 464 DI 10.1006/icar.1996.5625 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WP280 UT WOS:A1997WP28000019 ER PT J AU Mendis, SK Kemeny, SE Gee, RC Pain, B Staller, CO Kim, QS Fossum, ER AF Mendis, SK Kemeny, SE Gee, RC Pain, B Staller, CO Kim, QS Fossum, ER TI CMOS active pixel image sensors for highly integrated imaging systems SO IEEE JOURNAL OF SOLID-STATE CIRCUITS LA English DT Article DE active pixel sensor; cameras; CMOS image sensor AB A family of CMOS-based active pixel image sensors (APS's) that are inherently compatible with the integration of on-chip signal processing circuitry is reported, The image sensors were fabricated using commercially available 2-mu m CMOS processes and both p-well end n-well implementations were explored, The arrays feature random access, 5-V operation and transistor-transistor logic (TTL) compatible control signals. Methods of on-chip suppression of fixed pattern noise to less than 0.1% saturation are demonstrated. The baseline design achieved a pixel size of 40 mu m x 40 mu m with 26% fill-factor. Array sizes of 28 x 28 elements and 128 x 128 elements have been fabricated and characterized, Typical output conversion gain is 3.7 mu V/e(-) for the p-well devices and 6.5 mu V/e(-) for the n-well devices, Input referred read noise of 28 e(-) rms corresponding to a dynamic range of 76 dB was achieved, Characterization of various photogate pixel designs and a photodiode design is reported, Photoresponse variations for different pixel designs are discussed. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 19 TC 231 Z9 244 U1 3 U2 39 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9200 J9 IEEE J SOLID-ST CIRC JI IEEE J. Solid-State Circuit PD FEB PY 1997 VL 32 IS 2 BP 187 EP 197 DI 10.1109/4.551910 PG 11 WC Engineering, Electrical & Electronic SC Engineering GA WE539 UT WOS:A1997WE53900006 ER PT J AU YadidPecht, O Pain, B Staller, C Clark, C Fossum, E AF YadidPecht, O Pain, B Staller, C Clark, C Fossum, E TI CMOS active pixel sensor star tracker with regional electronic shutter SO IEEE JOURNAL OF SOLID-STATE CIRCUITS LA English DT Article DE active pixel sensors; dynamic range; electronic shutter; image sensors; photodiode arrays ID IMAGE SENSOR AB A 64 x 64 element CMOS active pixel sensor (APS) for star tracker applications is reported. The chip features an innovative regional electronic shutter through the use of an individual pixel reset architecture, Using the regional electronic shutter, each star in the field of view can have its own integration period, This way, simultaneous capture of bright stars with dim stars is accommodated, enabling a large increase in tracker capability. The chip achieves 80 dB dynamic range, 50 e-rms read noise, low dark current, and excellent electronic shutter linearity. RP YadidPecht, O (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 10 TC 37 Z9 37 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9200 J9 IEEE J SOLID-ST CIRC JI IEEE J. Solid-State Circuit PD FEB PY 1997 VL 32 IS 2 BP 285 EP 288 DI 10.1109/4.551925 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA WE539 UT WOS:A1997WE53900021 ER PT J AU Mesbahi, M Papavassilopoulos, GP AF Mesbahi, M Papavassilopoulos, GP TI On the rank minimization problem over a positive semidefinite linear matrix inequality SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article DE feedback synthesis; least element theory; linear matrix inequalities; rank minimization problem AB We consider the problem of minimizing the rank of a positive semidefinite matrix, subject to the constraint that an affine transformation of it is also positive semidefinite. Our method for solving this problem employs ideas from the ordered linear complementarity theory and the notion of the least element in a vector lattice. This problem is of importance in many contexts, for example in feedback synthesis problems; such an example is also provided. C1 UNIV SO CALIF,DEPT ELECT ENGN SYST,LOS ANGELES,CA 90089. RP Mesbahi, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 11 TC 72 Z9 74 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 0018-9286 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD FEB PY 1997 VL 42 IS 2 BP 239 EP 243 DI 10.1109/9.554402 PG 5 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA WH532 UT WOS:A1997WH53200007 ER PT J AU Decker, DR Olson, HM Tatikola, R Gutierrez, R Mysoor, NR AF Decker, DR Olson, HM Tatikola, R Gutierrez, R Mysoor, NR TI Multichip MMIC package for X and K-a bands SO IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY PART B-ADVANCED PACKAGING LA English DT Article DE computer modeling; IC packaging; microwave measurements; monolithic microwave integrated circuit (MMIC) AB A new multichip monolithic microwave integrated circuit (MMIC) package operable to X and Ka bands has been developed and tested, This package provides space for mounting up to five MMIC chips and has three radio frequency (RF) and five dc feed-throughs. The RF feed-throughs are of a mixed-mode, conductor-backed coplanar waveguide design that minimizes reflections and insertion loss over a wide bandwidth, The de feed-throughs permit bias access for up to five chips and internal mounting of chip bypass capacitors, Prototypes of the package have been built and tested using miniature coplanar probes, Test results indicate that the RF feed-throughs meet design goals to about 30 GHz and can be used to about 35 GHz, The package has been analyzed using a ''Composite Model'' approach in which individual elements are separately analyzed and modeled and then combined in a circuit simulator to provide a complete package model, This approach has provided quite good agreement with measured data. C1 PHOENIX MICROWAVE CORP,TELFORD,PA 18969. CALTECH,JET PROP LAB,SPACECRAFT TRANSPONDER GRP,PASADENA,CA 91109. RP Decker, DR (reprint author), LEHIGH UNIV,DEPT ELECT ENGN & COMP SCI,BETHLEHEM,PA 18015, 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 1070-9894 J9 IEEE T COMPON PACK B JI IEEE Trans. Compon. Packag. Manuf. Technol. Part B-Adv. Packag. PD FEB PY 1997 VL 20 IS 1 BP 27 EP 33 DI 10.1109/96.554520 PG 7 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA WH034 UT WOS:A1997WH03400005 ER PT J AU Hyer, PV AF Hyer, PV TI Use of infrared imagery in characterization of chemical vapor deposition reactors SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article DE chemical vapor deposition; gas dynamics; infrared; photogrammetry AB Infrared imagery was obtained of the exterior surfaces of a horizontal chemical vapor deposition reactor. These data revealed significant differences in flow pattern between hydrogen and nitrogen gases. The infrared pixel data were transformed into reactor coordinates and then merged with a three-dimensional data file of the reactor's external topology to create three-dimensional thermal maps of the exterior reactor surface. Such maps can prove useful both in helping to specify boundary conditions for modeling purposes and in revealing gross patterns in the flow. RP Hyer, PV (reprint author), NASA,LANGLEY RES CTR,LOCKHEED MARTIN ENGN & SCI CO,MAIL STOP 473,HAMPTON,VA 23681, USA. NR 3 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD FEB PY 1997 VL 38 IS 1 BP 17 EP 24 DI 10.1016/S1350-4495(96)00023-0 PG 8 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA WH949 UT WOS:A1997WH94900004 ER PT J AU Teng, YA Mount, D Puppo, E Davis, LS AF Teng, YA Mount, D Puppo, E Davis, LS TI Parallelizing an algorithm for visibility on polyhedral terrain SO INTERNATIONAL JOURNAL OF COMPUTATIONAL GEOMETRY & APPLICATIONS LA English DT Article; Proceedings Paper CT MSI Stony Brook Workshop on Computational Geometry CY OCT 14-16, 1993 CL RALEIGH, NC DE terrain visibility; parallel algorithms; CREW PRAM; profile tree AB The best known output-sensitive sequential algorithm for computing the viewshed on a polyhedral terrain from a given viewpoint was proposed by Katz, Overmars, and Sharir,(10) and achieves time complexity O((k + n alpha(n))log n) where n and k are the input and output sizes respectively, and alpha() is the inverse Ackermann's function. In this paper, we present a parallel algorithm that is based on the work mentioned above, and achieves O (log(2) n) time complexity, with work complexity O ((k + n alpha(n)) log n) in a CREW PRAM model. This improves on previous parallel complexity while maintaining work efficiency with respect to the best sequential complexity known. C1 UNIV MARYLAND,CTR AUTOMAT RES,COLLEGE PK,MD 20742. UNIV MARYLAND,DEPT COMP SCI,COLLEGE PK,MD 20742. CNR,IST MATEMAT APPL,I-16149 GENOA,ITALY. UNIV MARYLAND,INST ADV COMP STUDIES,COLLEGE PK,MD 20742. CALTECH,JET PROP LAB,PASADENA,CA 91109. OI Yang, Shuman/0000-0002-9638-0890 NR 14 TC 4 Z9 5 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-1959 J9 INT J COMPUT GEOM AP JI Int. J. Comput. Geom. Appl. PD FEB-APR PY 1997 VL 7 IS 1-2 BP 75 EP 84 DI 10.1142/S0218195997000065 PG 10 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA WT551 UT WOS:A1997WT55100005 ER PT J AU Marschall, J Milos, FS AF Marschall, J Milos, FS TI The calculation of anisotropic extinction coefficients for radiation diffusion in rigid fibrous ceramic insulations SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID FIBER ORIENTATION; HEAT-TRANSFER; MEDIA AB The specific anisotropic extinction coefficient e* couples the effective radiative properties of a fibrous insulation into the radiation diffusion equation. This coefficient can be calculated using electromagnetic scattering theory if fiber diameters, refractive indices and fiber orientation distributions are known. In general, fiber orientation distributions are not readily accessible and past calculations have considered fibers as either randomly distributed or normal to the heat flow direction. In certain rigid fibrous ceramic insulations neither of these cases apply well, and a simple procedure is described for approximating e* from values calculated for the random and normal orientation cases. The intrinsic error associated with this scaling procedure is investigated. Numerical computations for several test structures and fiber materials show the average error to be less than 5% for net heat flux and radiation conductivity calculations. Published by Elsevier Science Ltd. RP Marschall, J (reprint author), NASA,AMES RES CTR,THERMAL PROTECT MAT & SYST BRANCH,MAIL STOP 234-1,MOFFETT FIELD,CA 94035, USA. NR 20 TC 19 Z9 19 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD FEB PY 1997 VL 40 IS 3 BP 627 EP 634 DI 10.1016/0017-9310(96)00109-3 PG 8 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA VQ587 UT WOS:A1997VQ58700011 ER PT J AU Ponchak, GE Katehi, LPB AF Ponchak, GE Katehi, LPB TI Design of layered ridge dielectric waveguide for millimeter and sub-millimeter wave circuits SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE dielectric waveguide; image guide; insulated image guide; millimeter-wave waveguides ID MM-WAVE AB Design rules for Layered Ridge Dielectric Waveguide (LRDW) are presented for the first time through simple figures and closed form equations. The Effective Dielectric Constant (EDC) method is used to develop the design rules that account for typical circuit specifications such as higher order mode suppression, dispersion, attenuation and coupling between adjacent transmission Lines. Comparisons between the design of LRDW image guide, and millimeter-wave dielectric ridge guide are made. C1 UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. RP Ponchak, GE (reprint author), NASA, LEWIS RES CTR, MS 54-5 21000 BROOKPARK RD, CLEVELAND, OH 44135 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD FEB PY 1997 VL 18 IS 2 BP 369 EP 382 DI 10.1007/BF02677926 PG 14 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA WM704 UT WOS:A1997WM70400007 ER PT J AU Kniveton, DR Barrett, EC Dodge, JC AF Kniveton, DR Barrett, EC Dodge, JC TI The development of composite algorithms for global rainfall estimation using data from the DMSP SSM/I SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID IMAGES AB Considerable variation in the performance of passive microwave global rainfall algorithms, both spatially and temporally, was revealed by the first WetNet Precipitation Intercomparison Project, PIP-1, with no one algorithm achieving the best results, in all locations, and all the time. In this paper a Composite Algorithm Procedure is described for the Special Sensor Microwave/Imager (SSM/I) algorithms submitted to PIP-1, that attempts through combining the best algorithm results from different regions of the globe to achieve better overall global rainfall estimates than are possible from any individual algorithm alone. The Composite Algorithm Procedure (CAP) involves the segmentation of the globe into homogeneous regions, the production of validation statistics for the various algorithm results in the different regions, and the identification of combinations of algorithms which perform best globally. The segmentations were based on aspects of the spatial and temporal variability of rainfall, or the microwave properties of the surfaces of the Earth. Initial results for the Composite Algorithm Procedure are presented for a sample month (October 1987): these confirm that improved global rainfall products can be produced in this way. Code detailing a selected Composite Algorithm based on the segmentation method of the microwave properties of the Earth has been supplied to the WetNet Support Group at the Marshall Space Flight Center, Huntsville, Alabama, for experimental, regular production of global rainfall data sets real-time basis. C1 NASA, NASA HEADQUARTERS, WASHINGTON, DC 20546 USA. RP Kniveton, DR (reprint author), UNIV BRISTOL, DEPT GEOG, REMOTE SENSING UNIT, BRISTOL BS8 1SS, AVON, ENGLAND. NR 21 TC 1 Z9 1 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD FEB PY 1997 VL 18 IS 3 BP 517 EP 534 DI 10.1080/014311697218935 PG 18 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA WJ997 UT WOS:A1997WJ99700005 ER PT J AU Seraji, H Colbaugh, R AF Seraji, H Colbaugh, R TI Force tracking in impedance control SO INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH LA English DT Article ID MANIPULATORS AB This article presents two simple on-line schemes for force tracking within the impedance-control framework. The force-tracking capability of impedance control is particularly important for providing robustness in the presence of large uncertainties or variations in environmental parameters. The two proposed schemes generate the reference position trajec tory required to produce a desired contact force despite lack of knowledge of the environmental stiffness and location. The first scheme uses direct adaptive control to generate the reference position on-line as a function of the force-tracking error Alternatively, the second scheme utilizes an indirect adaptive strategy in which the environmental parameters are estimated on-line, and the required reference position is computed based on these estimates. In both schemes, adaptation allows automatic gain adjustment to provide a uniform performance despite variations in the environmental parameters. Simulation studies are presented for a 7-DOF Robotics Research arm using full arm dynamics, demonstrating that the adaptive schemes are able to compensate for uncertainties in both the environmental stiffness and location. The simulation studies also highlight the limitations of pure impedance control without the force-tracking capability for robust execution of realistic contact tasks. Experimental results are also presented for the Robotics Research arm to demonstrate that the end effector applies the desired contact force while exhibiting the specified impedance dynamics. C1 NEW MEXICO STATE UNIV, DEPT MECH ENGN, LAS CRUCES, NM 88003 USA. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 18 TC 98 Z9 106 U1 2 U2 9 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0278-3649 EI 1741-3176 J9 INT J ROBOT RES JI Int. J. Robot. Res. PD FEB PY 1997 VL 16 IS 1 BP 97 EP 117 DI 10.1177/027836499701600107 PG 21 WC Robotics SC Robotics GA WJ593 UT WOS:A1997WJ59300008 ER PT J AU Karasik, BS McGrath, WR Gaidis, MC AF Karasik, BS McGrath, WR Gaidis, MC TI Analysis of a high-T-c hot-electron superconducting mixer for terahertz applications SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; RADIATION; YBA2CU3O7; NONEQUILIBRIUM; PHOTORESPONSE; NANOBRIDGES; MICROBOLOMETER; CONDUCTIVITY; INTERFACE; NOISE AB The prospects of a YBa2Cu3O7-delta hot-electron bolometer mixer for a THz heterodyne receiver are discussed. The modeled device is a submicron bridge made from a 10-nm-thick film on a high thermal conductance substrate. The mixer performance expected for this device is analyzed in the framework of a two-temperature model which includes heating both of the electrons and the lattice. Also, the contribution of phonon diffusion from the film through the substrate and from the him to the normal metal contacts is evaluated. The intrinsic conversion efficiency and the noise temperature have been calculated as functions of the device size, local oscillator (LO) power, and ambient temperature. Assuming thermal fluctuations and Johnson noise to be the main sources of noise, a minimum single sideband mixer noise temperature of congruent to 2000 K is predicted. For our modeled device the intrinsic conversion loss at an intermediate frequency of 2.5 GHz is less than 10 dB and the required LO power is similar to 1-10 mu W. (C) 1997 American Institute of Physics. RP Karasik, BS (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109, USA. RI Gaidis, Michael/D-3327-2013; Karasik, Boris/C-5918-2011 NR 36 TC 48 Z9 48 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 FEB 1 PY 1997 VL 81 IS 3 BP 1581 EP 1589 DI 10.1063/1.365544 PG 9 WC Physics, Applied SC Physics GA WF017 UT WOS:A1997WF01700088 ER PT J AU Gretebeck, RJ Schoeller, DA Socki, RA DavisStreet, J Gibson, EK Schulz, LO Lane, HW AF Gretebeck, RJ Schoeller, DA Socki, RA DavisStreet, J Gibson, EK Schulz, LO Lane, HW TI Adaptation of the doubly labeled water method for subjects consuming isotopically enriched water SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE deuterium; oxygen-18; mass spectrometry; energy expenditure ID ENERGY-EXPENDITURE; FRACTIONATION; VALIDATION; SOLDIERS; EXERCISE; OXYGEN; O-18 AB The use of doubly labeled water (DLW) to measure energy expenditure is subject to error if the background abundance of the oxygen and hydrogen isotope tracers changes during the test period. This study evaluated the accuracy and precision of different methods by which such background isotope changes can be corrected, including a modified method that allows prediction of the baseline that would be achieved if subjects were to consume water from a given source indefinitely. Subjects in this study were eight women (4 test subjects and 4 control subjects) who consumed for 28 days water enriched to resemble drinking water aboard the United States space shuttle. Test subjects and control subjects were given a DLW dose on days 1 and 15, respectively. The change to an enriched water source produced a bias in expenditure calculations that exceeded 2.9 MJ/day (35%), relative to calculations from intake-balance. The proposed correction based on the predicted final abundance of O-18 and deuterium after equilibration to the new water source eliminated this bias, as did the traditional use of a control group. This new modified correction method is advantageous under field conditions when subject numbers are limited. C1 NASA,LYNDON B JOHNSON SPACE CTR,STABLE ISOTOPE LAB,SPACE & LIFE SCI DIRECTORATE,HOUSTON,TX 77058. UNIV CHICAGO,DEPT MED,COMM HUMAN NUTR & NUTR BIOL,CHICAGO,IL 60637. UNIV WISCONSIN,MILWAUKEE,WI 53201. RP Gretebeck, RJ (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,NUTR BIOCHEM LAB,SPACE & LIFE SCI DIRECTORATE,DIV MED SCI,HOUSTON,TX 77058, USA. FU NIDDK NIH HHS [DK-26678] NR 22 TC 18 Z9 18 U1 0 U2 4 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD FEB PY 1997 VL 82 IS 2 BP 563 EP 570 PG 8 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA WJ790 UT WOS:A1997WJ79000027 PM 9049738 ER PT J AU Siconolfi, SF Gretebeck, RJ Wong, WW Pietrzyk, RA Suire, SS AF Siconolfi, SF Gretebeck, RJ Wong, WW Pietrzyk, RA Suire, SS TI Assessing total body and extracellular water from bioelectrical response spectroscopy SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE bioimpedance; frequency; body fluids ID IMPEDANCE; PLASMA; VOLUME; DEUTERIUM; POSTURE; BROMIDE; SALIVA; URINE AB We developed and validated assessments for total body water (TBW) and extracellular water (ECW) by using two resistance values of a new electric circuit model (CM) (two resistors: a capacitor and an inductor) with or without body mass. Fluid shifts occurring after 40 min of supine rest did not decrease the validity of either estimate. CM estimates were valid; r = 0.941 to 0.969, low SE of estimates of 1.15-2.28 kg, nonsignificant mean differences (CM - dilution; %Delta = -0.4 to 1.3%) that were close to the expected measurement errors fur TBW (+/-1%) and ECW (+/-5%), and Bland-Altman pairwise comparisons that: showed equivalence between methods. The CM estimates of TBW and ECW had marginally better validity than the previously published bioimpedance models. The advantage of the CM model is its assessments of multiple fluid spaces and that it does not require gender-specific equations. We conclude that CM estimate of TBW is acceptable, whereas further validation is needed before the ECW estimate should be used in a clinical or research setting. C1 UNIV SPACE RES ASSOC,HOUSTON,TX 77058. BAYLOR COLL MED,DEPT PEDIAT,CHILDRENS NUTR RES CTR,AGR RES SERV,HOUSTON,TX 77030. USDA,STABLE ISOTOPE PROGRAM,HOUSTON,TX 77030. NASA,LYNDON B JOHNSON SPACE CTR,BIOMED OPERAT & RES BRANCH,KRUG LIFE SCI,BIOCHEM RES LAB,HOUSTON,TX 77058. RP Siconolfi, SF (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,SPACE BIOMED RES INST,EXERCISE PHYSIOL LAB,HOUSTON,TX 77058, USA. NR 26 TC 18 Z9 20 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 FEB PY 1997 VL 82 IS 2 BP 704 EP 710 PG 7 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA WJ790 UT WOS:A1997WJ79000045 PM 9049756 ER PT J AU Wang, JR Zhan, J Racette, P AF Wang, JR Zhan, J Racette, P TI Storm-associated microwave radiometric signatures in the frequency range of 90-220 GHz SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID ATMOSPHERIC WATER-VAPOR; 183 GHZ; RADIATIVE-TRANSFER; PRECIPITATION RADIOMETER; AIRCRAFT OBSERVATIONS; VERTICAL STRUCTURE; MONTHLY RAINFALL; DEEP CONVECTION; RETRIEVAL; SATELLITE AB Radiometric measurements were made by a millimeter-wave imaging radiometer (MIR) at the frequencies of 89, 150, 183.3 +/- 1, 183.3 +/- 3, 183.3 +/- 7, and 220 GHz aboard the NASA ER-2 aircraft at an altitude of about 20 km over two rainstorms: one in the western Pacific Ocean on 19 January 1993 and another in southern Florida on 5 October 1993. These measurements were complemented by nearly simultaneous observations by other sensors aboard the same aircraft and another aircraft flying along the same path. Analysis of data from these measurements, aided by radiative transfer and radar reflectivity calculations of hydrometeor profiles, which are generated by a general cloud ensemble model, demonstrates the utility of these frequencies for studying the structure of frozen hydrometeors associated with storms. Particular emphasis is placed on the three water vapor channels near 183.3 GHz. Results show that the radiometric signatures measured by these channels over the storm-associated scattering media bear a certain resemblance to those previously observed over a clear and fairly dry atmosphere with a cold ocean background. Both of these atmospheric conditions are characterized by a small amount of water vapor above a cold background. Radiative transfer calculations were made at these water vapor channels for a number of relative humidity profiles characterizing dry atmospheres over an ocean surface. The results are compared with the measurements to infer some characteristics of the environment near the scattering media. Furthermore, radiometric signatures from these channels display unique features for towering deep convective cells that could be used to identify the presence of such cells in storms. RP Wang, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,CODE 975,GREENBELT,MD 20771, USA. NR 39 TC 27 Z9 27 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD FEB PY 1997 VL 14 IS 1 BP 13 EP 31 DI 10.1175/1520-0426(1997)014<0013:SAMRSI>2.0.CO;2 PG 19 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA WD273 UT WOS:A1997WD27300002 ER PT J AU Caylor, IJ Heymsfield, GM Meneghini, R Miller, LS AF Caylor, IJ Heymsfield, GM Meneghini, R Miller, LS TI Correction of sampling errors in ocean surface cross-sectional estimates from nadir-looking weather radar SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID IMPULSE-RESPONSE; ROUGH SURFACE; RAIN RATE; AIRBORNE; SATELLITE; BACKSCATTERING AB The return from the ocean surface has a number of uses for airborne meteorological radar. The normalized surface cross section has been used for radar system calibration, estimation of surface winds, and in algorithms for estimating the path-integrated attenuation in rain. However, meteorological radars are normally optimized for observation of distributed targets that fill the resolution volume, and so a point target such as the surface can be poorly sampled, particularly at near-nadir. look angles. Sampling the nadir surface return at an insufficient rate results in a negative bias of the estimated cross section. This error is found to be as large as 4 dB using observations from a high-altitude airborne radar. An algorithm for mitigating the error is developed that is based upon the shape of the surface echo and uses the returned signal at the three range gates nearest the peak surface echo. C1 NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,MICROWAVE SENSORS BRANCH,GREENBELT,MD 20771. CLEMSON UNIV,DEPT PHYS & ASTRON,CLEMSON,SC 29634. SCI SYST & APPLICAT INC,LANHAM,MD. RP Caylor, IJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,MESOSCALE ATMOSPHER PROC BRANCH,CODE 912,GREENBELT,MD 20771, USA. NR 26 TC 6 Z9 6 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD FEB PY 1997 VL 14 IS 1 BP 203 EP 210 DI 10.1175/1520-0426(1997)014<0203:COSEIO>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA WD273 UT WOS:A1997WD27300016 ER PT J AU Jarzembski, MA Srivastava, V AF Jarzembski, MA Srivastava, V TI Low pressure experimental simulation of electrical discharges above and inside a cloud SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID SPRITES94 AIRCRAFT CAMPAIGN; LOW-LIGHT VIDEO; LUMINOUS STRUCTURES; STRATOSPHERE; THUNDERSTORMS; IONOSPHERE; FLASHES AB A low pressure laboratory experiment to generate sporadic electrical discharges in either a particulate dielectric or air, representing a competing path of preferred electrical breakdown, was investigated. At high pressures, discharges occurred inside the dielectric particulate; at low pressures, discharges occurred outside the dielectric particulate; at a transition pressure regime, which depends on conductivity of the dielectric particulate, discharges were simultaneously generated in both particulate dielectric and air. Unique use of a particulate dielectric was critical for sporadic discharges at lower pressures which were not identical in character to discharges without the particulate dielectric. Application of these experimental results to the field of atmospheric electricity and simulation of the above-cloud type discharges that have recently been documented, called jets and sprites, are discussed. C1 USRA,INST GLOBAL CHANGE RES & EDUC,GLOBAL HYDROL & CLIMATE CTR,HUNTSVILLE,AL 35806. RP Jarzembski, MA (reprint author), NASA,MSFC,GLOBAL HYDROL & CLIMATE CTR,977 EXPLORET BLVD,HUNTSVILLE,AL 35806, USA. NR 25 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 1997 VL 59 IS 3 BP 271 EP 279 DI 10.1016/S1364-6826(96)00022-3 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA WL049 UT WOS:A1997WL04900002 ER PT J AU Stubenrauch, CJ DelGenio, AD Rossow, WB AF Stubenrauch, CJ DelGenio, AD Rossow, WB TI Implementation of subgrid cloud vertical structure inside a GCM and its effect on the radiation budget SO JOURNAL OF CLIMATE LA English DT Article ID ERBE AB The GISS (Goddard Institute for Space Studies) GCM (general circulation model) predicts stratiform and convective cloud cover and optical thickness at nine atmospheric levels in horizontal grid boxes of 4 degrees lat x 5 degrees long. Until now, the radiative fluxes were calculated once per grid box, assuming clear sky or a complete cloud cover. Here, a refinement of the radiative flux calculation is explored by introducing a horizontal subgrid cloud overlap scheme in which cloud blocks are formed by adjacent cloud layers using maximum overlap. Different cloud blocks are separated by an atmospheric level of clear sky and are assumed to overlap randomly inside the grid box. This subgrid cloud structure allows determination of the occurrence probabilities of columns with different vertical structures inside each horizontal grid box. Then, radiative fluxes are calculated for each of these columns. The radiative fluxes of each horizontal grid box are obtained as the occurrence probability weighted sum of the column fluxes. Compared with the standard GCM version, the horizontal subgrid cloud overlap scheme leads to significant geographical and seasonal changes of the global mean cloud effects on top-of-atmosphere radiative fluxes that are in slightly better agreement with satellite observations. Two extreme assumptions of horizontal cloud size distributions (very small cloud elements or one horizontally continuous cloud) within the cloud blocks are also tested, leading to different column occurrence probabilities. Whereas the global and zonal mean cloud effects on radiative fluxes stay the same, regional differences between the two assumptions (i.e., uncertainties ib GCM cloud cover and radiative fluxes produced by a lack of knowledge of, subgrid cloud size distributions) can be as large as 15% in cloud cover and 25 (50) W m(-2) in LW (SW) net fluxes. The implemented cloud overlap scheme is necessary to study radiative effects of different cloud types separately so that one can better understand the discrepancies in cloud radiative effects between observations and model. This study is not possible with the standard version of the GCM because the instantaneous fluxes do not correspond to realistic cloud structures. But by comparing in more detail the radiative effects of high opaque, cirrus, midlevel, and low clouds with help of the new scheme in GCM and in simultaneous Earth Radiation Budget Experiment and International Satellite Cloud Climatology Project observations, one finds out that high opaque clouds in the GCM have a cloud cover that is too small and are too thin over winter hemisphere ocean, whereas cirrus clouds appear with a cloud cover that is too high. Low clouds in the GCM seem to be too low by about 100 hPa. C1 NASA, GODDARD SPACE FLIGHT CTR, INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP Stubenrauch, CJ (reprint author), ECOLE POLYTECH, METEOROL DYNAM LAB, F-91128 PALAISEAU, FRANCE. RI Del Genio, Anthony/D-4663-2012; Rossow, William/F-3138-2015 OI Del Genio, Anthony/0000-0001-7450-1359; NR 15 TC 44 Z9 45 U1 2 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 1997 VL 10 IS 2 BP 273 EP 287 DI 10.1175/1520-0442(1997)010<0273:IOSCVS>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ835 UT WOS:A1997WJ83500008 ER PT J AU Xue, YK Sellers, PJ Zeng, FJ Schlosser, CA AF Xue, YK Sellers, PJ Zeng, FJ Schlosser, CA TI Use of midlatitude soil moisture and meteorological observations to validate soil moisture simulations with biosphere and bucket models - Comments SO JOURNAL OF CLIMATE LA English DT Article C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV MARYLAND,DEPT METEOROL,COLLEGE PK,MD 20742. RP Xue, YK (reprint author), INST GLOBAL ENVIRONM & SOC INC,CTR OCEAN LAND ATMOSPHERE STUDIES,4041 POWDER MILL RD,SUITE 320,CALVERTON,MD 20705, USA. NR 12 TC 11 Z9 14 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 1997 VL 10 IS 2 BP 374 EP 376 DI 10.1175/1520-0442(1997)010<0374:COUOMS>2.0.CO;2 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ835 UT WOS:A1997WJ83500016 ER PT J AU Yee, HC AF Yee, HC TI Explicit and implicit multidimensional compact high-resolution shock-capturing methods: Formulation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID FINITE-DIFFERENCE SCHEMES; HYPERBOLIC CONSERVATION-LAWS; GLOBAL ASYMPTOTIC-BEHAVIOR; STATE NUMERICAL-SOLUTIONS; FLUID-DYNAMICS; TVD SCHEMES; EQUATIONS; PROPAGATION; FLOWS AB Two families of explicit and implicit compact high-resolution shock-capturing methods for the multidimensional compressible Euler equations for fluid dynamics are constructed, Some of these schemes can be fourth- and sixth-order accurate away from discontinuities. For the semi-discrete case their shock-capturing properties are of the total variation diminishing (TVD), total variation bounded (NB), total variation diminishing in the mean (TVDM), essentially nonoscillatory (ENO), or positive type of scheme for 1D scalar hyperbolic conservation laws and are positive schemes in more than one dimension. These higher-order compact schemes require the same grid stencil per spatial direction as their second-order noncompact cousins. The added terms over the second;order noncompact cousins involve extra vector additions but no added flux evaluations. Due to the construction, these schemes can be viewed as approximations to genuinely multidimensional schemes in the sense that they might produce less distortion in spherical type shocks and are more accurate in vortex type flows than schemes based purely on 1D extensions. The extension of these families of compact schemes to coupled nonlinear systems can be accomplished using the Foe approximate Riemann solver, the generalized Steger and Warming flux-vector splitting, or the van Leer type flux-vector splitting. Modification to existing high-resolution second- or third-order non-compact shock-capturing computer codes is minimal, High-resolution shock-capturing properties can also be achieved via a variant of the second-order Lax-Friedrichs numerical flux without the use of Riemann solvers for coupled nonlinear systems with comparable operations count to their classical shock-capturing counterparts. An efficient and compatible high-resolution shock-capturing filter for spatially fourth;and sixth-order classical compact and noncompact schemes is discussed. The simplest extension to viscous flows can be achieved by using the standard fourth-order compact or non-compact formula for the viscous terms. (C) 1997 Academic Press. RP Yee, HC (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. NR 61 TC 36 Z9 41 U1 1 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB PY 1997 VL 131 IS 1 BP 216 EP 232 DI 10.1006/jcph.1996.5608 PG 17 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA WJ865 UT WOS:A1997WJ86500013 ER PT J AU Sha, YG Su, CH Lehoczky, SL AF Sha, YG Su, CH Lehoczky, SL TI Mass flux of ZnSe1-xSx and ZnSe1-xTex by physical vapor transport SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID CADMIUM-ZINC TELLURIDE; SILICA GLASS AMPOULES; RESIDUAL-GAS; ZN-TE; ABSORPTION; PRESSURES; SYSTEMS; GROWTH; CD AB Mass fluxes of ZnSeS and ZnSeTe during physical vapor transport (PVT) were measured in the temperature range 1060-1160 degrees C using an in situ dynamic technique. The starting binary materials were either baked out or distilled under vacuum to obtain near-congruently subliming compositions. The amount and composition of the residual gas inside the experimental ampoules were measured after each run using a total pressure gauge. A one-dimensional diffusion limited analysis of the mass transport rate for the PVT system was performed including the residual gas species. Four diffusion equations were solved simultaneously using a numerical method and the mass transport rates as well as the alloy compositions of the deposited materials were predicted as functions of the thermal field, the stoichiometry of the source material, and the pressure of the residual gas. Reasonable agreement between the experimental and theoretical results was observed. RP Sha, YG (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 32 TC 1 Z9 1 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 FEB PY 1997 VL 171 IS 3-4 BP 516 EP 524 DI 10.1016/S0022-0248(96)00696-3 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA WF409 UT WOS:A1997WF40900028 ER PT J AU Verigin, M Kotova, G Shutte, N Remizov, A Szego, K Tatrallyay, M Apathy, I Rosenbauer, H Livi, S Richter, AK Schwingenschuh, K Zhang, TL Slavin, J Lemaire, J AF Verigin, M Kotova, G Shutte, N Remizov, A Szego, K Tatrallyay, M Apathy, I Rosenbauer, H Livi, S Richter, AK Schwingenschuh, K Zhang, TL Slavin, J Lemaire, J TI Quantitative model of the Martian magnetopause shape and its variation with the solar wind ram pressure based on Phobos 2 observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETIC-FIELD; BOW SHOCK; DYNAMIC PRESSURE; MARS; VENUS; INTERCALIBRATION; MAGNETOTAIL; INSTRUMENTS; PLASMA; MAGNETOSPHERE AB A model of the Martian magnetopause is developed for the period of maximum solar activity which simultaneously describes (1) the observed relation between the solar wind ram pressure rho V-2 and the magnetopause position in the magnetotail, (2) the observed relation between rho V-2 and the flaring angle, and (3) a few magnetopause crossing observations above the day side of the planet. The shape of the magnetopause is determined from the equation of pressure balance across this boundary when both the magnetic pressure (with a planetary magnetic moment of (0.8-1.0)x10(22) G cm(3)) and the ionospheric pressure are taken into account in the planetary magnetosphere. The specific feature of the model is the ''stagnation'' of the subsolar magnetopause when the ram pressure increases to higher values (greater than or equal to 6x10(-9) dyn cm(-2)). C1 KFKI,ATOM ENERGY RES INST,H-1525 BUDAPEST,HUNGARY. KFKI,RES INST PARTICLE & NUCL PHYS,H-1525 BUDAPEST,HUNGARY. MAX PLANCK INST AERON,D-37191 KATLENBURG DUHM,GERMANY. SPACE RES INST,A-8010 GRAZ,AUSTRIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. BELG INST RUIMTE AERON,B-1180 BRUSSELS,BELGIUM. RP Verigin, M (reprint author), MOSCOW SPACE RES INST,PROFSOYUZNAYA 84-32,MOSCOW 117810,RUSSIA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 41 TC 16 Z9 17 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2147 EP 2155 DI 10.1029/96JA01460 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800013 ER PT J AU Kotova, G Remizov, A Shutte, N Verigin, M Lemaire, J Livi, S Rosenbauer, H Schwingenschuh, K Zhang, TL Slavin, J Szego, K Tatrallyay, M AF Kotova, G Remizov, A Shutte, N Verigin, M Lemaire, J Livi, S Rosenbauer, H Schwingenschuh, K Zhang, TL Slavin, J Szego, K Tatrallyay, M TI Study of the solar wind deceleration upstream of the Martian terminator bow shock SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SPECULARLY REFLECTED IONS; PHOBOS-2 OBSERVATIONS; UPPER ATMOSPHERES; OXYGEN CORONA; MARS; VENUS; HYDROGEN; ORIGIN; ATOMS AB Solar wind plasma and magnetic data obtained near the Martian terminator bow shock by the TAUS energy spectrometer and the MAGMA magnetometer onboard the Phobos 2 spacecraft are analyzed. It is revealed that on average the solar wind stream is slowing down just upstream of the bow shock. Nearly inverse correlation is found between the values of the velocity decrease and the undisturbed solar wind density for the outbound (mostly quasi-parallel) bow shock crossings, while for the inbound crossings (mostly quasi-perpendicular) this correlation is observed only for the velocity decrease upstream of the shock foot. This result permits us to distinguish between the two possible reasons causing solar wind deceleration: (1) mass loading of the solar wind flow by planetary ions originating from the corona of Mars, and (2) solar wind protons reflected from the bow shock. The solar wind deceleration upstream of the bow shock foot turned to be approximately dawn-dusk symmetric. On the basis of the revealed relation between the velocity decrease and upstream solar wind density, a coronal density profile is deduced which is in agreement with earlier results for the subsolar region. According to this profile, the density of the hot oxygen corona of Mars might be similar to 3 times higher in the period of observations than the estimations of the ''extreme'' corona model suggests, even taking into account the possible contribution of the hydrogen corona to the solar wind deceleration effect. C1 BELG INST RUIMTE AERON,B-1180 BRUSSELS,BELGIUM. MAX PLANCK INST AERON,D-37191 KATLENBURG DUHM,GERMANY. SPACE RES INST,A-8010 GRAZ,AUSTRIA. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. KFKI,RES INST PARTICLE & NUCL PHYS,H-1525 BUDAPEST,HUNGARY. RP Kotova, G (reprint author), RUSSIAN ACAD SCI,SPACE RES INST,PROFSOYUZNAYA 84-32,MOSCOW 117810,RUSSIA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 30 TC 19 Z9 19 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2165 EP 2173 DI 10.1029/96JA01533 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800015 ER PT J AU Craven, PD Gallagher, DL Comfort, RH AF Craven, PD Gallagher, DL Comfort, RH TI Relative concentration of He+ in the inner magnetosphere as observed by the DE 1 retarding ion mass spectrometer SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PLASMASPHERE; IONOSPHERE; MODEL; TEMPERATURES; RADIATION; DENSITY; QUIET; FLUX; H+ AB With observations from the retarding ion mass spectrometer on the Dynamics Explorer 1 from 1981 through 1984, we examine the He+ to H+ density ratios as a function of altitude, latitude, season, local time, geomagnetic and solar activity. We find that the ratios are primarily a function of geocentric distance and the solar EUV input. The ratio of the densities, when plotted as a function of geocentric distance, decrease by an order of magnitude from 1 to 4.5 R(E). After the He+ to H+ density ratios are adjusted for the dependence on radial distance, they decrease nonlinearly by a factor of 5 as the solar EUV proxy varies from about 250 to about 70. When the mean variations with both these parameters are removed, the ratios appear to have no dependence on geomagnetic activity, and weak dependence on local time or season, geomagnetic latitude, and L shell. C1 UNIV ALABAMA,CTR SPACE PLASMA & AERON RES,HUNTSVILLE,AL 35899. RP Craven, PD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,SPACE SCI LAB,HUNTSVILLE,AL 35812, USA. NR 37 TC 79 Z9 79 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2279 EP 2289 DI 10.1029/96JA02176 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800026 ER PT J AU Birn, J Thomsen, MF Borovsky, JE Reeves, GD McComas, DJ Belian, RD Hesse, M AF Birn, J Thomsen, MF Borovsky, JE Reeves, GD McComas, DJ Belian, RD Hesse, M TI Substorm ion injections: Geosynchronous observations and test particle orbits in three-dimensional dynamic MHD fields SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOSPHERIC PLASMA ANALYZER; SHEET BOUNDARY-LAYER; MAGNETOTAIL RECONNECTION; MAGNETIC RECONNECTION; CURRENT DISRUPTION; CURRENT WEDGE; NEUTRAL LINE; ACCELERATION; ONSET; MODEL AB We investigate particle acceleration and the flux increases associated with substorm particle injections using geosynchronous observations and test proton orbits in the dynamic fields of a three-dimensional MHD simulation of neutral line formation and dipolarization in the magnetotail. The energetic particle flux changes obtained from the test particle orbits agree well with observations that demonstrate rapid ion flux increases at energies above similar to 20 keV but little change at lower energies. The ''injection region'' inferred from the test particles not only has a sharp earthward boundary (the usual injection boundary) but also a sharp but ragged tailward boundary. The earthward portion of enhanced ion flux can be traced to the enhanced cross-tail electric field associated with the collapse and dipolarization of the inner tail, whereas the tailward edge is closely associated with the near-Earth x-type neutral line. Because of the rapid earthward motion of accelerated ions away from the neutral line, this boundary is displaced earthward to where the energetic ions become more adiabatic in the stronger dipolar field. Lower-energy ions are not affected by cross-tail acceleration in the strong E(y) fields because their earthward ExB drift dominates the cross-tail drift, except very close to the neutral line. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP LOS ALAMOS NATL LAB, MS D466, LOS ALAMOS, NM 87545 USA. RI Hesse, Michael/D-2031-2012; Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 54 TC 101 Z9 101 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2325 EP 2341 DI 10.1029/96JA03032 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800030 ER PT J AU Badhwar, GD AF Badhwar, GD TI Drift rate of the South Atlantic anomaly SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID RADIATION AB A portion of the secular change of the geomagnetic field leads to a drift of the trapped belt South Atlantic Anomaly (SAA). If this drift is not taken into account, models of the trapped particle population give erroneous predictions of particle fluxes. The dose rates measured on two manned spacecrafts, Skylab (50 degrees inclination x 438 km orbit) and Mir orbital station (51.65 degrees inclination x 400 km orbit), were used to determine the drift rate of the SAA. The longitude and latitude drift rates of the SAA as a whole, between 1973 and 1995, were estimated to be 0.28 +/- 0.03 degrees W per year, and 0.08 +/- 0.03 degrees N per year, respectively. These measurements are consistent with determinations made using the AP8 models for radiation trapped belts and are in excellent agreement with drift rates observed for the geomagnetic field. RP Badhwar, GD (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,MAIL CODE SN,HOUSTON,TX 77058, USA. NR 11 TC 33 Z9 34 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2343 EP 2349 DI 10.1029/96JA03494 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800031 PM 11539371 ER PT J AU Stasiewicz, K Gustafsson, G Marklund, G Lindqvist, PA Clemmons, J Zanetti, L AF Stasiewicz, K Gustafsson, G Marklund, G Lindqvist, PA Clemmons, J Zanetti, L TI Cavity resonators and Alfven resonance cones observed on Freja SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID FIELD LINE RESONANCES; COLD INHOMOGENEOUS-PLASMA; LOW-BETA-PLASMA; AURORAL ARC; WAVE-PROPAGATION; ELECTRIC-FIELDS; EXACT EQUATIONS; MAGNETOSPHERE; IONOSPHERE; ACCELERATION AB Multiresolution wavelet analysis of magnetic field, electric field, and plasma density records taken on Freja during strong auroral events shows evidence for cavity Alfven resonators in the topside ionosphere. The cavity (or transverse) resonators consist of standing perpendicular wave modes which are trapped inside plasma cavities of different perpendicular scales. The smallest size cavities have perpendicular widths comparable to the electron skin depth, lambda(s) = 2 pi c/omega(pe), and are presumably associated with the resonance cones of Alfven waves launched by a magnetospheric source. The Alfven resonance cones (ARCs) carry intense field-aligned currents, support strong parallel electric fields and represent discharge and heating channels for auroral particles. We have made a detailed analysis of the electromagnetic properties of two singular auroral structures associated with ARCs. Field-aligned currents at the resonance structures reach intensities of 100-300 rho Am-2 in the upward and downward directions and are carried mainly by cold ionospheric plasma in both directions. The parallel electric field of ARCs is observed at amplitudes up to 100 mV/m, which is 2 orders of magnitude larger than expected for the unbounded Alfven waves. Field-aligned electron beams accelerated inside ARCs are observed to drive Langmuir waves with parallel electric field occasionally exceeding 1 V/m. One of the analyzed ARC structures has electromagnetic and particle properties characteristic of ''black aurora'' with electric field diverging from the center of the cavity; the other has converging electric field. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. ROYAL INST TECHNOL, S-10044 STOCKHOLM, SWEDEN. JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MD 20723 USA. RP SWEDISH INST SPACE PHYS, S-75591 UPPSALA, SWEDEN. NR 44 TC 84 Z9 86 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2565 EP 2575 DI 10.1029/96JA03462 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800054 ER PT J AU LengyelFrey, D Thejappa, G MacDowall, RJ Stone, RG Phillips, JL AF LengyelFrey, D Thejappa, G MacDowall, RJ Stone, RG Phillips, JL TI Ulysses observations of wave activity at interplanetary shocks and implications for type II radio bursts SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EARTHS BOW SHOCK; SOLAR-WIND; EMISSION MECHANISMS; PLASMA FREQUENCY; FORESHOCK; UPSTREAM; GENERATION; ELECTRONS; REGION; NOISE AB We present the first quantitative investigation of interplanetary type II radio emission in which in situ waves measured at interplanetary shocks are used to compute radio wave intensities for comparison with type II observations. This study is based on in situ measurements of 42 in-ecliptic forward shocks as well as 10 intervals of type II emission observed by the Ulysses spacecraft between 1 AU and 5 AU. The analysis involves comparisons of statistical properties of type II bursts and in situ waves, since the type II events are not related to particular shock passages at Ulysses. Most of the 42 shocks are associated with the occurrence of electrostatic waves near the time of shock passage at Ulysses. These waves, which are identified as electron plasma waves and ion acoustic-like waves, are typically most intense several minutes before shock passage. This suggests that wave-wave interactions might be of importance in electromagnetic wave generation and that type II source regions are located immediately upstream of the shocks. We use the in situ wave measurements to compute type II brightness temperatures, assuming that emission at the fundamental of the electron plasma frequency is generated by the merging of electron plasma waves and ion acoustic waves or the decay of electron plasma waves into ion acoustic and transverse waves. Second harmonic emission is assumed to be produced by the merging of electron plasma waves. The latter mechanism requires that a portion of the electron plasma wave distribution is backscattered, presumably by density inhomogeneities in regions of observed ion acoustic wave activity. The computed type II brightness temperatures are found to be consistent with observed values for both fundamental and second harmonic emission, assuming that strong (similar or equal to 10(-4) V/m) electron plasma waves and ion acoustic waves are coincident and that the electron plasma waves have phase velocities less than about 10 times the electron thermal velocity. Thus a single conversion mechanism provides a plausible scenario for generation of both fundamental and harmonic interplanetary type II emission. C1 NASA, GODDARD SPACE FLIGHT CTR, EXTRATERR PHYS LAB, GREENBELT, MD 20771 USA. NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM USA. RP LengyelFrey, D (reprint author), COMP SCI CORP, 4401 SUITLAND RD, SUITLAND, MD 20746 USA. RI MacDowall, Robert/D-2773-2012 NR 44 TC 25 Z9 25 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1997 VL 102 IS A2 BP 2611 EP 2621 DI 10.1029/96JA02871 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WF648 UT WOS:A1997WF64800058 ER PT J AU Hsu, PF Farmer, JT AF Hsu, PF Farmer, JT TI Benchmark solutions of radiative heat transfer within nonhomogeneous participating media using the Monte Carlo and YIX method SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE combustion; numerical methods; radiation ID NONGRAY MEDIA C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,THERMAL & LIFE SUPPORT DIV,HUNTSVILLE,AL 35812. RP Hsu, PF (reprint author), FLORIDA INST TECHNOL,MECHAN & AEROSPACE ENGN PROGRAMS,MELBOURNE,FL 32901, USA. NR 7 TC 24 Z9 25 U1 1 U2 6 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD FEB PY 1997 VL 119 IS 1 BP 185 EP 188 DI 10.1115/1.2824087 PG 4 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA WK254 UT WOS:A1997WK25400026 ER PT J AU Cuenca, RH Brouwer, J Chanzy, A Droogers, P Galle, S Gaze, SR Sicot, M Stricker, H AnguloJaramillo, R Boyle, SA Bromley, J Chebhouni, AG Cooper, JD Dixon, AJ Fies, JC Gandah, M Gaudu, JC Laguerre, L Lecocq, J Soet, M Steward, HJ Vandervaere, JP Vauclin, M AF Cuenca, RH Brouwer, J Chanzy, A Droogers, P Galle, S Gaze, SR Sicot, M Stricker, H AnguloJaramillo, R Boyle, SA Bromley, J Chebhouni, AG Cooper, JD Dixon, AJ Fies, JC Gandah, M Gaudu, JC Laguerre, L Lecocq, J Soet, M Steward, HJ Vandervaere, JP Vauclin, M TI Soil measurements during HAPEX-Sahel intensive observation period SO JOURNAL OF HYDROLOGY LA English DT Article ID NEUTRON PROBE MEASUREMENTS; TIME DOMAIN REFLECTOMETRY; ERROR ANALYSIS; WATER-CONTENT; HYDRAULIC CONDUCTIVITY; SPATIAL STANDPOINT; LOCAL STANDPOINT; IRRIGATED FIELDS; EFEDA EXPERIMENT; MOBILHY AB This article describes measurements made at each sits and for each vegetation cover as part of the soils program for the HAPEX-Sahel regional scale experiment. The measurements were based on an initial sampling scheme and included profile soil water content, surface soil water content, soil water potential. infiltration rates. additional measurements on core samples, and grain size analysis. The measurements were used to categorize the state of the surface and profile soil water regimes during the experiment and to derive functional relationships for the soil water characteristic curve, unsaturated hydraulic conductivity function, and infiltration function. Sample results for different supersites and different vegetation covers are presented showing soil water profiles and total soil water storage on days corresponding to the experimental 'Golden Days'. Sample results are also presented for spatial and temporal distribution of surface moisture content and infiltration tests. The results demonstrate that the major experimental objective of monitoring the supersites during the most rapid vegetative growth stage with the largest change of the surface energy balance following the rainy season was very nearly achieved. Separation of the effects of probable root activity and drainage of the soil profile is possible. The potential for localized advection between the bare soil and vegetation strips of the tiger bush sites is demonstrated. C1 INT CROPS RES INST SEMI ARID TROP, NIAMEY, NIGER. AGR UNIV WAGENINGEN, DEPT SOIL SCI & GEOL, NL-6700 AA WAGENINGEN, NETHERLANDS. INRA, F-84143 MONTFAVET, FRANCE. AGR UNIV WAGENINGEN, DEPT WATER RESOURCES, NL-6708 PA WAGENINGEN, NETHERLANDS. ORSTOM, NIAMEY, NIGER. INST HYDROL, WALLINGFORD OX10 8BB, OXON, ENGLAND. INST RADIOISOTOPES, NIAMEY, NIGER. UNIV GRENOBLE 1, CNRS 1512, INGP, LAB ETUD TRANSFERTS HYDROL & ENVIRONM, F-38041 GRENOBLE 9, FRANCE. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. INST NATL RECH AGRON NIGER, NIAMEY, NIGER. CTR NATL ETUD SPATIALES, LAB ETUD & RECH TELEDETECT SPATIAL, F-31055 TOULOUSE, FRANCE. RP OREGON STATE UNIV, DEPT BIORESOURCE ENGN, CORVALLIS, OR 97331 USA. RI Droogers, Peter/A-6370-2013; Galle, Sylvie/D-4935-2013 OI Galle, Sylvie/0000-0002-3100-8510 NR 47 TC 28 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 EI 1879-2707 J9 J HYDROL JI J. Hydrol. PD FEB PY 1997 VL 189 IS 1-4 BP 224 EP 266 PG 43 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA XA788 UT WOS:A1997XA78800012 ER PT J AU Chanzy, A Schmugge, TJ Calvet, JC Kerr, Y vanOevelen, P Grosjean, O Wang, JR AF Chanzy, A Schmugge, TJ Calvet, JC Kerr, Y vanOevelen, P Grosjean, O Wang, JR TI Airborne microwave radiometry on a semi-arid area during HAPEX-Sahel SO JOURNAL OF HYDROLOGY LA English DT Article ID SOIL-MOISTURE; RAINFALL ESTIMATION; EMISSION; FIELDS AB Airborne microwave radiometric measurements in the framework of the HAPEX-Sahel Experiment were performed by the Push Broom Microwave Radiometer (PBMR) and the PORTOS radiometer. The flights of both radiometers produced an original set of data covering the 1.4-90 GHz range of frequency. The East and West Central Super Sites were the areas most intensively observed by the microwave radiometers. Over those sites, several brightness temperature (T-B) maps are available at seven dates distributed over a 1 month period in the middle of the rainy season. A comparison of the two radiometers demonstrates their radiometric quality and the precision of the localization of the microwave observations. At 1.4 GHz, the vegetation had very little effect on the soil microwave emission. Maps of soil moisture were developed using a single linear relationship between T-B and the surface soil moisture. There is an important spatial heterogeneity in the soil moisture distribution, which is explained by both the soil moisture hydrodynamic properties and the localization of the precipitation fields. At 5.05 GHz, the vegetation must be accounted for to infer soil moisture from the microwave observations. A method based on a simple radiative transfer model and on microwave data has shown encouraging results. (C) 1997 Elsevier Science B.V. All rights reserved. C1 USDA,HYDROL LAB,BELTSVILLE,MD 20740. INRA,UNITE SCI SOL,F-84914 AVIGNON 9,FRANCE. METEO FRANCE,CNRM,F-31057 TOULOUSE,FRANCE. LERTS,CESBIO,F-31055 TOULOUSE,FRANCE. AGR UNIV WAGENINGEN,DEPT WATER RESOURCES,NL-6709 PA WAGENINGEN,NETHERLANDS. CTR NATL ETUD SPATIALES,F-31055 TOULOUSE,FRANCE. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RI Calvet, Jean-Christophe/A-8762-2012 OI Calvet, Jean-Christophe/0000-0001-6425-6492 NR 25 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD FEB PY 1997 VL 189 IS 1-4 BP 285 EP 309 PG 25 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA XA788 UT WOS:A1997XA78800014 ER PT J AU Teng, WL Choudhury, BJ Wang, JR AF Teng, WL Choudhury, BJ Wang, JR TI The effects of laterite and associated terrain components on PBMR response in HAPEX-Sahel SO JOURNAL OF HYDROLOGY LA English DT Article ID SURFACE SOIL-MOISTURE; MICROWAVE EMISSION; MODEL AB Terrain characteristics such as roughness and vegetation have been shown to significantly affect the interpretation of microwave brightness temperatures (TBS) for mapping soil moisture. This study, a part of the 1992 HAPEX-Sahel experiment (Hydrologic Atmospheric pilot Experiment in the Sahel). aimed to determine the effects of laterite and associated terrain components (i.e. vegetation, soil, and exposed water bodies) on the Ts response of the Pushbroom Microwave Radiometer (PBMR, L-band, 21 cm wavelength), using the NS001 Thematic Mapper Simulator data as a surrogate for ground data. Coincident PBMR and NS001 data acquired from the high altitude (about 1500 m) long transect flights were processed to obtain TBS and radiances, respectively. The transects covered a range of moisture conditions. For this preliminary evaluation, no atmospheric corrections were applied, and the data sets were aligned by matching the acquisition times of the data records. NS001 pixels (about 3 m) were averaged to approximate the resolution of the PBMR (about 450 m), before their flight line data were compared. The laterite plateaux were found to have a surprisingly strong effect on the PBMR T-B response. T-B variations along the flight line could largely be explained by a combination of density and dielectric properties of laterite. The effect of surface moisture was distinguishable from the laterite effect, with the distinction apparently related to the occurrence of ephemeral pools of water after rainfall. Model simulated TBS agreed reasonably well with the observed TBS. C1 NASA,GODDARD SPACE FLIGHT CTR,HYDROL SCI BRANCH,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,MICROWAVE SENSORS & DATA COMMUN BRANCH,GREENBELT,MD 20771. RP Teng, WL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,GREENBELT,MD 20771, USA. NR 27 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD FEB PY 1997 VL 189 IS 1-4 BP 310 EP 329 PG 20 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA XA788 UT WOS:A1997XA78800015 ER PT J AU Chehbouni, A LoSeen, D Njoku, EG Lhomme, JP Monteny, B Kerr, YH AF Chehbouni, A LoSeen, D Njoku, EG Lhomme, JP Monteny, B Kerr, YH TI Estimation of sensible heat flux over sparsely vegetated surfaces SO JOURNAL OF HYDROLOGY LA English DT Article ID ENERGY BALANCE; INFRARED THERMOMETRY; REGIONAL SCALES; TEMPERATURE; MODEL; EVAPOTRANSPIRATION; EVAPORATION; RESISTANCE; RANGELAND; WHEAT AB The approach of using remote sensing of surface temperature to estimate spatially distributed surface energy balance components is very attractive. This approach has been applied successfully over surfaces with near full vegetation cover. However, large discrepancies between measured and simulated surface fluxes have been observed over surfaces with sparse vegetation cover. The reason for these discrepancies is that the assumption that radiative surface temperature can be equated to aerodynamic surface temperature is not correct over sparsely vegetated surfaces. In this study an empirical model, relating radiative-aerodynamic surface temperature difference to radiative-air temperature gradient and leaf area index, was used to estimate sensible heat flux over sparse shrub in the Central East supersite during the Hydrologic and Atmospheric Pilot Experiment in the Sahel (HAPEX-Sahel) measurement campaign. The result shows that this parameterization leads to reasonable estimates of sensible heat flux; the root mean square error (RMSE) was about 50 W m(-2) A second data set over sparse cotton in Arizona had a RMSE of about 20 W m(-2). Although the results of this study are encouraging, one should be cautious, however, because there is a need for additional investigation of this procedure. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. CTR ETUD SPATIALE BIOSPERE CESBIO,F-31400 TOULOUSE,FRANCE. RP Chehbouni, A (reprint author), ORSTOM,HYDROL LAB,911 AVE AGROPOLIS,BP 5045,F-34032 MONTPELLIER,FRANCE. RI Lo Seen, Danny/C-2679-2008; Lhomme, Jean Paul /G-7236-2015 OI Lo Seen, Danny/0000-0002-7773-2109; NR 26 TC 18 Z9 18 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD FEB PY 1997 VL 189 IS 1-4 BP 855 EP 868 PG 14 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA XA788 UT WOS:A1997XA78800041 ER PT J AU Nicholson, SE Marengo, JA Kim, J Lare, AR Galle, S Kerr, YH AF Nicholson, SE Marengo, JA Kim, J Lare, AR Galle, S Kerr, YH TI A daily resolution evapoclimatonomy model applied to surface water balance calculations at the HAPEX-Sahel supersites SO JOURNAL OF HYDROLOGY LA English DT Article ID CLIMATONOMIC DESCRIPTION; SENEGALESE SAHEL; ENERGY BALANCE; LARGE-SCALE; VARIABILITY; RAINFALL AB This paper describes the results of Lettau's evapoclimatonomy model at daily time scales as applied to the Central East and Southern supersites of the HAPEX-Sahel region in Niger, West Africa. A revised version of the evapoclimatonomy model has been applied to the millet and bush fallow (Guiera senegalensis) fields at both supersites during the intensive observation period (IOP; 20 August-12 October, 1992), using daily means of precipitation, potential evapotranspiration, solar radiation, normalized difference vegetation index (NDVI) from the HAPEX-Sahel observations, as well as vegetation and soil parameters for the region. Soil moisture and immediate and delayed evapotranspiration and runoff are predicted, It has been found that the model predicts the soil moisture at the Central Eastern supersite quite well. However, it overestimates soil moisture at the Southern supersite even though its variability is captured by the model, Model results also indicate that soil moisture estimates are very sensitive to the NDVI-evaporivity relationship, which is robust at monthly scales but needs more revision for application at the daily scale. Overall the model performance when applied to the IOP observations is sufficiently good to indicate the suitability of the climatonomy for water balance studies on daily time scales. C1 NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,GREENBELT,MD 20771. ORSTOM,HYDROL LAB,MONTPELLIER,FRANCE. LERTS,TOULOUSE,FRANCE. RP Nicholson, SE (reprint author), FLORIDA STATE UNIV,DEPT METEOROL,TALLAHASSEE,FL 32306, USA. RI Marengo, Jose /J-9382-2012; Galle, Sylvie/D-4935-2013 OI Marengo, Jose /0000-0002-8154-2762; Galle, Sylvie/0000-0002-3100-8510 NR 44 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD FEB PY 1997 VL 189 IS 1-4 BP 946 EP 964 PG 19 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA XA788 UT WOS:A1997XA78800045 ER PT J AU Spencer, MN Chackerian, C Giver, LP Brown, LR AF Spencer, MN Chackerian, C Giver, LP Brown, LR TI Temperature dependence of nitrogen broadening of the NO fundamental vibrational band SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID DIODE-LASER MEASUREMENTS; NITRIC-OXIDE; RANGE; SPECTROSCOPY; PARAMETERS; LINEWIDTHS; LINES AB We report measured N-2-broadening coefficients, gamma(T), of approximately 70 transitions of the ground electronic state fundamental vibration-rotation band (nu = 1 <-- 0) of NO at 183, 213, and 296 K. In addition to the broadening asymmetry previously observed between the (2) Pi(3/2) and (2) Pi(1/2) state transitions, we also observed for most of the (2) Pi(1/2) transitions an increased broadening of the f-lambda over the e-lambda components. The temperature dependence of the broadening coefficients was characterized by the power law, gamma(Gamma) = gamma(296) (296/T)(n). Our gamma(296) values are on average systematically smaller than those of J. Ballard et al. [J. Mel. Spectrosc. 127, 70-82 (1988)] by 4.7%. We obtained an average n of 0.708 +/- 0.059 for the (2) Pi(1/2) subband and 0.699 +/- 0.067 for the (2) Pi(3/2) subband. These average n values fortuitously agree very well with the average n values derived from measurements of NO-N-2 broadening cited above (n = 0.70) since individual differences areas large as 15%. (C) 1997 Academic Press. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. CALTECH,JET PROP LAB,PASADENA,CA 91109. NR 18 TC 11 Z9 11 U1 1 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD FEB PY 1997 VL 181 IS 2 BP 307 EP 315 DI 10.1006/jmsp.1996.7169 PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA WH318 UT WOS:A1997WH31800007 ER PT J AU Muller, HSP Helminger, P Young, SH AF Muller, HSP Helminger, P Young, SH TI Millimeter and submillimeter spectroscopy of chlorine nitrate: The CI quadrupole tensor and the harmonic force field SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article; Proceedings Paper CT 51st International Symposium on Molecular Spectroscopy CY JUN 10-14, 1996 CL OHIO STATE UNIV, COLUMBUS, OH HO OHIO STATE UNIV ID ROTATIONAL SPECTRUM; MOLECULAR-STRUCTURE; CONSTANTS; VIBRATION; MATRICES; DIOXIDE; NO2 AB The rotational spectra of (ClONO2)-Cl-35 and (ClONO2)-Cl-37 in their ground and first excited torsional states (v(9) = 1) have been reinvestigated in selected regions between 84 and 441 GHz. An extensive set of spectroscopic constants has been determined, enabeling more accurate predictions of line positions in the submillimeter region. Accidental near-degeneracies of rotational levels cause perturbations of the quadrupole patterns, allow the observation of a Delta J = 2 transition, and result in the precise determination of chi(ab). The quartic distortion constants along with the vibrational wavenumbers and inertial defect differences have been used for a calculation of the harmonic force field. The assignments of the vibrational modes in terms of internal coordinates are discussed. The results are compared with properties of related molecules such as Cl2O. (C) 1997 Academic Press. C1 UNIV S ALABAMA,DEPT PHYS,MOBILE,AL 36688. UNIV S ALABAMA,DEPT CHEM,MOBILE,AL 36688. RP Muller, HSP (reprint author), CALTECH,JET PROP LAB,MAIL STOP 183-301,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 38 TC 19 Z9 19 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD FEB PY 1997 VL 181 IS 2 BP 363 EP 378 DI 10.1006/jmsp.1996.7183 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA WH318 UT WOS:A1997WH31800014 ER PT J AU Wu, Z Ortiz, R Fort, A Barzoukas, M Marder, SR AF Wu, Z Ortiz, R Fort, A Barzoukas, M Marder, SR TI Synthesis and optical properties of a new class of organometallic compounds: Organometallic merocyanines SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE organometallic; merocyanines; non-linear optics (NLO) ID ORGANIC-MOLECULES; HYPERPOLARIZABILITIES; POLARIZATION; COMPLEXES AB A new class of organometallic compounds, organometallic merocyanines based upon the [(eta-(C5H5)(2)Fe-2(CO)(2)(mu-CO)] fragment acting as a donor, have been synthesized and characterized. The non-linear optical properties of these organometallic merocyanines have been determined by electric field induced second harmonic generation and indicate that these compounds have large second-order optical non-linearities. C1 CALTECH,BECKMAN INST,MAT RESOURCE CTR,PASADENA,CA 91125. IPCMS,UM 046 CNRS,F-67037 STRASBOURG,FRANCE. CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,PASADENA,CA 91109. NR 20 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD FEB 1 PY 1997 VL 528 IS 1-2 BP 217 EP 219 DI 10.1016/S0022-328X(96)06575-8 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA WR163 UT WOS:A1997WR16300025 ER PT J AU Yu, ZJ Schopf, PS McCreary, JP AF Yu, ZJ Schopf, PS McCreary, JP TI On the annual cycle of upper-ocean circulation in the eastern equatorial Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SEA-SURFACE TEMPERATURE; EL-NINO; MODEL; DYNAMICS; CURRENTS AB An oceanic general circulation model is used to investigate the annual cycle of the near-surface currents in the eastern equatorial Pacific Ocean; in particular, the causes of the springtime increase bf eastward momentum that reverses the westward surface flow and intensifies the Equatorial Undercurrent are examined. A set of process experiments are carried out that isolates effects due to three forcing mechanisms: local zonal and meridional winds, and remote zonal winds. It is demonstrated that the springtime weakening of the local easterly trades is the primary cause of the eastward-momentum increase. In addition, due to meridional advection, the local southerly wind drives a westward current on the equator throughout the year; this flow is weakest in the spring, and therefore this process also contributes to the anomalous eastward flow. On the other hand, remote forcing tends to weaken the springtime momentum increase: Anomalous easterlies in the far-western and central Pacific during the winter excite upwelling-favorable Kelvin waves that generate anomalous westward flow in the eastern Pacific during the early spring. C1 UNIV MARYLAND,DEPT METEOROL,JOINT CTR EARTH SYST SCI,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,COUPLED CLIMATE DYNAM GRP,GREENBELT,MD 20771. NOVA SE UNIV,OCEANOG CTR,DANIA,FL. NR 29 TC 14 Z9 14 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD FEB PY 1997 VL 27 IS 2 BP 309 EP 324 DI 10.1175/1520-0485(1997)027<0309:OTACOU>2.0.CO;2 PG 16 WC Oceanography SC Oceanography GA WK255 UT WOS:A1997WK25500006 ER PT J AU Palumbo, G Craig, RA Whiting, EW Park, C AF Palumbo, G Craig, RA Whiting, EW Park, C TI Measured specific intensity from 130 TO 900 nm at the stagnation point of a model in an arcjet flow of 7.8 km/sec SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB The absolute specific intensity (W/cm(2)-mu-sr) spectrum (also known as the radiative heating rate spectrum), incident on the stagnation point of a blunt model placed in an arcjet wind tunnel, is presented. The test model was a flat disk, 15 cm in diameter, which produced an effective nose radius of about 60 cm. The test conditions in the arcjet are column were 80% air, 20% argon, 1.02 atm pressure, 950 A, and 1800 V. The flow conditions in the test section were 0.51 atm and 7.8 km/sec, which correspond to flight in the Earth's atmosphere at about 76 km altitude. The total spectrum was recorded and calibrated from 110 to 900 nm. The intensity calibration is considered to be accurate to within about a factor of 2 from 130 to 900 nm. The tests were made in a separate experimental setup. The measured radiative heating rate in the vacuum-ultraviolet from 130 to 200 nm, is about 10% of the total heating rate from 130 to 900 nm. This result is in qualitative agreement with an estimate of 25% for a larger vehicle (nose radius of 259 cm) flying in the Earth's atmosphere at 77.1 km altitude and 9.5 km/sec. These data show that the radiation and its spectral content, incident on a blunt model in an arcjet, are similar to those expected for flight in the Earth's atmosphere at similar conditions, except for much stronger NO radiation from 200 to 300 nm. The source of this strong NO radiation appears to be in the freestream ahead of the bowshock wave. The physical and chemical conditions in the freestream of an arcjet are far more complex than those in actual flight, due to the excitation and expansion processes. However, the results presented show that arcjet tests can be used to simulate the radiation environment during atmospheric entry, and can provide the data needed to advance the ability to calculate realistic radiative heating rates under non-equilibrium flight condition. (C) 1997 Elsevier Science Ltd. C1 THERMOSCI INST,MOFFETT FIELD,CA 94035. MCAT INST,MOFFETT FIELD,CA 94035. RP Palumbo, G (reprint author), NASA,AMES RES CTR,MS 230-2,MOFFETT FIELD,CA 94035, USA. NR 22 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD FEB PY 1997 VL 57 IS 2 BP 207 EP 236 DI 10.1016/S0022-4073(96)00138-0 PG 30 WC Optics; Spectroscopy SC Optics; Spectroscopy GA WH022 UT WOS:A1997WH02200005 ER PT J AU Allen, DR Stanford, JL Elson, LS Fishbein, EF Froidevaux, L Waters, JW AF Allen, DR Stanford, JL Elson, LS Fishbein, EF Froidevaux, L Waters, JW TI The 4-day wave as observed from the Upper Atmosphere Research Satellite microwave limb sounder SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERALIZED ELIASSEN-PALM; PLANETARY-WAVES; POTENTIAL VORTICITY; ELECTROSTATICS ANALOGY; BAROTROPIC INSTABILITY; ANTARCTIC MESOSPHERE; POLAR STRATOSPHERE; WINTER; OSCILLATIONS; HEMISPHERE AB The ''4-day wave'' is an eastward moving quasi-nondispersive feature with period near 4 days occurring near the winter polar stratopause. This paper presents evidence of the 4-day feature in Microwave Limb Sounder (MLS) temperature, geopotential height, and ozone data from the late southern winters of 1992 and 1993. Spacetime spectral analyses reveal a double-peaked temperature structure consisting of one peak near the stratopause and another in the lower mesosphere, with an out-of-phase relationship between the two peaks. This double-peaked structure is reminiscent of recent three-dimensional barotropic/baroclinic instability model predictions and is observed here for the first time. The height variation of the 4-day ozone signal is shown to compare well with a linear advective-photochemical tracer model. Negative regions of quasigeostrophic potential vorticity (PV) gradient and positive Eliassen-Palm flux divergence are shown to occur, consistent with instability dynamics playing a role in wave forcing. Spectral analyses of PV derived from MLS geopotential height fields reveal a 4-day signal peaking near the polar stratopause. The three-dimensional structure of the 4-day wave resembles the potential vorticity ''charge'' concept, wherein a PV anomaly in the atmosphere (analogous to an electrical charge in a dielectric material) induces a geopotential field, a vertically oriented temperature dipole, and circulation about the vertical axis. C1 IOWA STATE UNIV,DEPT PHYS & ASTRON,AMES,IA 50011. CALTECH,JET PROP LAB,PASADENA,CA. NR 41 TC 18 Z9 18 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD FEB 1 PY 1997 VL 54 IS 3 BP 420 EP 434 DI 10.1175/1520-0469(1997)054<0420:TDWAOF>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WL454 UT WOS:A1997WL45400004 ER PT J AU Zuffada, C Crisp, D AF Zuffada, C Crisp, D TI Particle scattering in the resonance regime: Full-wave solution for axisymmetric particles with large aspect ratios SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article DE clouds and aerosols; axisymmetric particles; resonance regime ID HEXAGONAL ICE CRYSTALS; SINGLE-SCATTERING; CIRRUS CLOUDS; RADIATIVE PROPERTIES; OPTICAL-PROPERTIES; LIGHT-SCATTERING; GRAINS AB Reliable descriptions of the optical properties of clouds and aerosols are essential for studies of radiative transfer in planetary atmospheres. Mie scattering algorithms provide accurate estimates of these properties for spherical particles with a wide range of sizes and refractive indices, but these methods are not valid for nonspherical particles (e.g., ice crystals, mineral dust, and smoke). Even though a host of methods exist for deriving the optical properties of nonspherical particles that are very small or very large compared with the wavelength, only a few methods are valid in the resonance regime, where the particle dimensions are comparable with the wavelength. Most such methods are not ideal for particles with sharp edges or large axial ratios. We explore the utility of an integral equation approach for deriving the single-scattering optical properties of axisymmetric particles with large axial ratios. The accuracy of this technique is shown for spheres of increasing size parameters and an ensemble of randomly oriented prolate spheroids of size parameter equal to 10.079368. In this last case our results are compared with published results obtained with the T-matrix approach. Next we derive cross sections, single-scattering albedos, and phase functions for cylinders, disks, and spheroids of ice with dimensions extending from the Rayleigh to the geometric optics regime. Compared with those for a standard surface integral equation method, the storage requirement and the computer time needed by this method are reduced, thus making it attractive for generating databases to be used in multiple-scattering calculations. Our results show that water ice disks and cylinders are more strongly absorbing than equivalent volume spheres at most infrared wavelengths. The geometry of these particles also affects the angular dependence of the scattering. Disks and columns with maximum linear dimensions larger than the wavelength scatter much more radiation in the forward and backward directions and much less radiation at intermediate phase angles than equivalent volume spheres. (C) 1997 Optical Society of America [S0740-3232(97)02102-9] RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 25 TC 3 Z9 3 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1084-7529 EI 1520-8532 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD FEB PY 1997 VL 14 IS 2 BP 459 EP 469 DI 10.1364/JOSAA.14.000459 PG 11 WC Optics SC Optics GA WE035 UT WOS:A1997WE03500013 ER PT J AU Ryer, CH vanMontfrans, J Moody, KE AF Ryer, CH vanMontfrans, J Moody, KE TI Cannibalism, refugia and the molting blue crab SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE eelgrass; marsh creeks; predation; selfish herd; tidal ID TIDAL-MARSH CREEK; LOWER CHESAPEAKE BAY; CALLINECTES-SAPIDUS RATHBUN; SEAGRASS MEADOW; MICROHABITAT SELECTION; POPULATION-DYNAMICS; TEMPORAL PATTERNS; ZOSTERA-MARINA; SELFISH HERD; PREY AB In this study, we examined how habitat and tidal stage influence predation upon molting blue crabs Callinectes sapidus. On 3 separate occasions we monitored the survival of tethered soft crabs in each of 2 different-sized marsh creeks and 2 seagrass sites, during both low and high tides. On one of these occasions, we also tethered hard crabs. Survival was much lower for soft crabs than for hard crabs, indicating that crabs may be particularly vulnerable when they molt. In both seagrass and marsh creeks, there was a tidal influence upon soft crab survival, with greater survival during low tides. There was no generalized difference in survival of soft crabs between habitats, i.e. marsh creek versus grassbed. Survival was high in the small marsh creek, but lower in the large marsh creek. In both creeks survival remained relatively constant throughout the summer. In contrast, survival did not differ between the 2 seagrass sites and was comparable to that in the small marsh creek early in the summer, but decreased to levels comparable to the large marsh creek by summers end. In the marsh creek, micro-habitat also influenced survival, with greater survival along the creek edge micro-habitats than in the creek centers. Cannibalism was the only identifiable source of mortality among tethered crabs. These results demonstrate that where and when a crab molts may greatly influence its chances for survival. C1 OREGON STATE UNIV, HATFIELD MARINE SCI CTR, DEPT FISHERIES & WILDLIFE, NEWPORT, OR 97365 USA. VIRGINIA INST MARINE SCI, COLL WILLIAM & MARY, SCH MARINE SCI, GLOUCESTER POINT, VA 23062 USA. RP Ryer, CH (reprint author), OREGON STATE UNIV, HATFIELD MARINE SCI CTR, NOAA, NATL MARINE FISHERIES SERV, NEWPORT, OR 97365 USA. NR 26 TC 38 Z9 39 U1 1 U2 8 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PD FEB PY 1997 VL 147 IS 1-3 BP 77 EP 85 DI 10.3354/meps147077 PG 9 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA WP969 UT WOS:A1997WP96900007 ER PT J AU Robinson, DH Kolber, Z Sullivan, CW AF Robinson, DH Kolber, Z Sullivan, CW TI Photophysiology and photoacclimation in surface sea ice algae from McMurdo Sound, Antarctica SO MARINE ECOLOGY PROGRESS SERIES LA English DT Article DE Antarctic; sea ice algae; photoacclimation; photoinhibition; pump and probe fluorometry ID PHOTOSYNTHETIC ENERGY-CONVERSION; PHOTOSYSTEM-II; CHLOROPHYLL FLUORESCENCE; MICROBIAL COMMUNITIES; HIGH-RESOLUTION; HIGH IRRADIANCE; TEMPERATURE; PHYTOPLANKTON; LIGHT; GROWTH AB Microalgal absorption, pigment concentrations, photophysiology and the efficiency for energy conversion at photosystem II (Fv/Fm) were measured for surface ice algal communities freshly collected from saline ponds overlying fast ice in McMurdo Sound, Antarctica, during austral spring and summer 1989-90. These parameters also were measured for surface ice algae exposed in the laboratory to irradiances from 4 to 600 mu mol photons m(-2) s(-1). Freshly collected algae exhibited a pigment composition consistent with acclimation to high irradiance, which included low intracellular chlorophyll (chl) a concentrations (0.19 to 0.50 kg m(-3)), low accessory photosynthetic pigments relative to chl a (chl c: chl a = 0.16 to 0.25 mol mol(-1); fucoxanthin: chl a = 0.53 to 0.77 mol mol(-1)), and high photoprotective pigments relative to chl a (diatoxanthin + diadinoxanthin: chl a = 0.19 to 0.50 mol mol(-1)). In contrast, the photoadaptive index for freshly collected algae (E(k) = 37 to 45 mu mol photons m(-2) s(-1)) was less than the daily average photosynthetically active radiation reaching the algal communities during the study (110 to 720 mu mol photons m(-2) s(-1)), indicating that the algae were not acclimated to their high irradiance environment. No depression of photosynthesis was observed in the photosynthesis-irradiance curve at irradiances less than or equal to 250 mu mol photons m(-2) s(-1) (4- to 8-fold greater than E(k)) However, Fv/Fm (0.24 to 0.43) and the quantum yield of photosynthesis (phi(C), 0.018 to 0.037 mol C mol(-1) absorbed photons) were low in freshly collected algae, which suggests that the algae were photoinhibited under natural illumination conditions. Within 32 h after shifting algae to low irradiance, a relaxation from high-light stress was observed. Photosynthetic efficiency (alpha(b)), phi(C) and Fv/Fm increased by 165, 170 and 67%, respectively, and E(k) decreased by 60%. In addition, whereas total cellular concentrations of photosynthetic pigments were unchanged, diatoxanthin:chl a decreased by >75% due to the conversion of diatoxanthin to diadinoxanthin. The presence of xanthophyll cycling and an observed depression of relative maximum and minimum quantum yields of fluorescence in response to high irradiance indicate that algae employed the dissipation of absorbed energy from the pigment bed of photosystem II as a protection mechanism from high irradiance. Indications of additional photoprotection mechanisms and photoinhibitory damage were also observed. These results indicate that surface ice algae successfully inhabit the surface ice habitat by employing a strategy of low-light harvesting, absorbed energy dissipation, and tolerance to photoinhibitory damage. C1 BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. UNIV SO CALIF, DEPT BIOL SCI, LOS ANGELES, CA 90089 USA. RP Robinson, DH (reprint author), NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, CODE 971, GREENBELT, MD 20771 USA. NR 59 TC 28 Z9 29 U1 1 U2 13 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0171-8630 J9 MAR ECOL PROG SER JI Mar. Ecol.-Prog. Ser. PD FEB PY 1997 VL 147 IS 1-3 BP 243 EP 256 DI 10.3354/meps147243 PG 14 WC Ecology; Marine & Freshwater Biology; Oceanography SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Oceanography GA WP969 UT WOS:A1997WP96900022 ER PT J AU Convertino, VA Bloomfield, SA Greenleaf, JE AF Convertino, VA Bloomfield, SA Greenleaf, JE TI An overview of the issues: Physiological effects of bed rest and restricted physical activity SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE deconditioning; exercise training; cardiovascular; muscle; bone; exercise; disuse ID MIDDLE-AGED MEN; EXERCISE; RESPONSES; CAPACITY; STRENGTH; BEDREST; PERFORMANCE; MECHANISMS; REDUCTION; ENDURANCE AB Reduction of exercise capacity with confinement to bed rest is well recognized. Underlying physiological mechanisms include dramatic reductions in maximal stroke volume, cardiac output, and oxygen uptake. However, bed rest by itself does not appear to contribute to cardiac dysfunction. Increased muscle fatigue is associated with reduced muscle blood flow, red cell volume, capillarization, and oxidative enzymes. Loss of muscle mass and bone density may be reflected by reduced muscle strength and higher risk for injury to bones and joints. The resultant deconditioning caused by bed rest can be independent of the primary disease and physically debilitating in patients who attempt to reambulate to normal active living and working. A challenge to clinicians and health care specialists has been the identification of appropriate and effective methods to restore physical capacity of patients during or after restricted physical activity associated with prolonged bed rest. The examination of physiological responses to bed rest deconditioning and exercise training in healthy subjects has provided significant information to develop effective rehabilitation treatments. The successful application of acute exercise to enhance orthostatic stability, daily endurance exercise to maintain aerobic capacity, or specific resistance exercises to maintain musculoskeletal integrity rather than the use of surgical, pharmacological, and other medical treatments for clinical conditions has been enhanced by investigation and understanding of underlying mechanisms that distinguish physical deconditioning from the disease. This symposium presents an overview of cardiovascular and musculoskeletal deconditioning associated with reduced physical work capacity following prolonged bed rest and exercise training regimens that have proven successful in ameliorating or reversing these adverse effects. C1 TEXAS A&M UNIV,DEPT HLTH & KINESIOL,COLLEGE STN,TX 77843. NASA,AMES RES CTR,DIV LIFE SCI,LAB HUMAN ENVIRONM PHYSIOL,MOFFETT FIELD,CA 94035. RP Convertino, VA (reprint author), ARMSTRONG LAB,AOCY,PHYSIOL RES BRANCH,DIV CLIN SCI,2507 KENNEDY CIRCLE,BROOKS AFB,TX 78235, USA. NR 48 TC 137 Z9 150 U1 1 U2 16 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 FEB PY 1997 VL 29 IS 2 BP 187 EP 190 DI 10.1097/00005768-199702000-00004 PG 4 WC Sport Sciences SC Sport Sciences GA WH755 UT WOS:A1997WH75500004 PM 9044221 ER PT J AU Greenleaf, JE AF Greenleaf, JE TI Intensive exercise training during bed rest attenuates deconditioning SO MEDICINE AND SCIENCE IN SPORTS AND EXERCISE LA English DT Article DE isotonic exercise; isokinetic exercise; plasma volume; orthostatic tolerance; metabolism; psychological performance ID ENDURANCE AB A 30-d 6 degrees head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (h) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and (i) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest. RP Greenleaf, JE (reprint author), NASA,AMES RES CTR,DIV LIFE SCI 23911,GRAVITAT RES BRANCH,LAB HUMAN ENVIRONM PHYSIOL,MOFFETT FIELD,CA 94035, USA. NR 26 TC 47 Z9 50 U1 0 U2 2 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 FEB PY 1997 VL 29 IS 2 BP 207 EP 215 DI 10.1097/00005768-199702000-00007 PG 9 WC Sport Sciences SC Sport Sciences GA WH755 UT WOS:A1997WH75500007 PM 9044224 ER PT J AU Rao, KBS Castelli, MG Allen, GP Ellis, JR AF Rao, KBS Castelli, MG Allen, GP Ellis, JR TI Critical assessment of the mechanistic aspects in HAYNES 188 during low-cycle fatigue in the range 25 degrees C to 1000 degrees C SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID TEMPERATURE; DEFORMATION; SUPERALLOY; SUBSTRUCTURE; DISLOCATIONS; DEPENDENCE; BEHAVIOR; ALLOYS; SLIP AB The law-cycle fatigue (LCF) behavior of a wrought cobalt-base superalloy, Haynes 188, has been investigated over a range of temperatures between 25 degrees C and 1000 degrees C employing a triangular waveform and a constant strain amplitude of +/-0.4 pet. Correlations between macroscopic cyclic deformation and fatigue life with the various microstructural phenomena were enabled through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), detailing the crack initiation and propagation modes, deformation substructure, and carbide precipitation. Cyclic stress response varied as a complex function of temperature. Dynamic strain aging (DSA) was found to occur over a wide temperature range between 300 degrees C and 750 degrees C. In the DSA domain, the alloy exhibited marked cyclic hardening with a pronounced maximum at 650 degrees C. Dynamic strain aging has been documented through the occurrence of serrated yielding, inverse temperature dependence of maximum cyclic stress, and cyclic inelastic strain; developed at half of the fatigue: life. Additionally, the alloy also displayed a negative strain rate sensitivity of cyclic Stress in the DSA regime. These macroscopic features in the DSA domain were accompanied by the substructure comprised of coplanar distribution of dislocations associated with the formation of pileups, stacking faults, and very high dislocation density. Toward the end of the DSA domain, dislocation pinning by M(23)C(6) precipitates occurred predominantly. The deformation behavior below and above the DSA domain has also. been investigated in detail. The temperature dependence of LCF life showed a maximum at approximate to 300 degrees C. The drastic reduction in life between 300 degrees C and 850 degrees C has been ascribed primarily to the deleterious effects of DSA on crack initiation and propagation, while the lower life at temperatures less than 200 degrees C has been attributed to the combined influence of low ductility and larger cyclic response stress. C1 NASA,LEWIS RES CTR,STRUCT FATIGUE BRANCH,CLEVELAND,OH 44135. NASA,LEWIS RES CTR,NYMA INC,MAT DEV & FATIGUE SECT,CLEVELAND,OH 44135. RP Rao, KBS (reprint author), INDIRA GANDHI CTR ATOM RES,MECH PROPERTIES SECT,KALPAKKAM 603102,TAMIL NADU,INDIA. NR 52 TC 39 Z9 39 U1 3 U2 8 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD FEB PY 1997 VL 28 IS 2 BP 347 EP 361 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA WL436 UT WOS:A1997WL43600010 ER PT J AU Tran, TL Sherif, JS Mikulski, C Wang, M AF Tran, TL Sherif, JS Mikulski, C Wang, M TI MY-STAR: A methodology and system for tracing and analyzing requirements SO MICROELECTRONICS AND RELIABILITY LA English DT Article AB This paper describes a methodology developed at the Jet Propulsion Laboratory (JPL), and designed for the process of requirements engineering and management. MY-STAR provides techniques for specifying, refining, allocating, baselining, sharing, changing, storing and reporting on requirements and requirements metrics. In support of MY-STAR, the tool STAFR (System for Tracing and Analyzing Functional Requirements) has been prototyped by the Ground Systems Group (Software Product Assurance) as part of the process assurance support to four different projects within the Deep Space Network (DSN) at JPL. The results show that STAFR provides an effective means for capturing in one place requirements, while enabling refinement, analysis, traceability of test cases to requirements, and other trade-off artifacts associated with the specifications, prioritization, allocation and planning of requirements. It does so without the significant overhead typically associated with knowledge-based systems. RP Tran, TL (reprint author), CALTECH,JET PROP LAB,SOFTWARE PROD ASSURANCE,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0026-2714 J9 MICROELECTRON RELIAB JI Microelectron. Reliab. PD FEB PY 1997 VL 37 IS 2 BP 297 EP 303 DI 10.1016/0026-2714(95)00129-8 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA VZ203 UT WOS:A1997VZ20300010 ER PT J AU Negueruela, I Grove, JE Coe, MJ Fabregat, J Finger, MH Phlips, BF Roche, P Steele, IA Unger, SJ AF Negueruela, I Grove, JE Coe, MJ Fabregat, J Finger, MH Phlips, BF Roche, P Steele, IA Unger, SJ TI Multiwavelength observations of an outburst from the Be/X-ray transient 4U0115+63 in 1994 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE binaries, general; stars, emission-line, Be; stars, individual, V635 Cas; pulsars, general; infrared, stars; X-rays, stars ID OPTICAL COUNTERPART; UHURU CATALOG; 4U 0115+63; STARS; DISKS; LUMINOSITY; 4U-0115+63; DISCOVERY; X0115+634; SPECTRUM AB We present OSSE observations of the recurrent X-ray transient 4U0115+63 during the 1994 May-June outburst, spanning the brightest period of the outburst and covering more than a full binary orbit. We also present long-term observations of the optical counterpart V635 Cassiopeiae and the long-term hard X-ray light curve determined by BATSE pulsed observations. Optical and infrared photometry as well as H alpha spectroscopy reveals that the correlation between the optical and X-ray behaviour of the source, although evident, is not simple. We discuss the recent history of the system, paying particular attention to the extremely unusual behaviour of the Be star. We investigate the possible mechanisms for this behaviour and find that the centrifugal inhibition of accretion theory provides an adequate explanation for the X-ray activity. Our data, however, point strongly against the previous assumption that the accretion disc around the neutron star is responsible for the very large variations in optical luminosity. These variations, as well as those in the shape and strength of the H alpha line, must originate in the Be circumstellar envelope. C1 USN, RES LAB, EO HULBURT CTR SPACE RES, WASHINGTON, DC 20375 USA. UNIV VALENCIA, DEPT ASTRON & ASTROFIS, E-46100 BURJASSOT, VALENCIA, SPAIN. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. UNIV SPACE RES ASSOC, WASHINGTON, DC 20024 USA. UNIV SUSSEX, CTR ASTRON, MAPS, BRIGHTON BN1 9QH, E SUSSEX, ENGLAND. LIVERPOOL JOHN MOORES UNIV, ASTROPHYS GRP, LIVERPOOL L3 3AF, MERSEYSIDE, ENGLAND. RUTHERFORD APPLETON LAB, DEPT SPACE SCI, DIDCOT OX11 0QX, OXON, ENGLAND. RP Negueruela, I (reprint author), UNIV SOUTHAMPTON, DEPT PHYS, SOUTHAMPTON SO17 1BJ, HANTS, ENGLAND. RI Negueruela, Ignacio/L-5483-2014; Fabregat, Juan/F-9066-2016 OI Negueruela, Ignacio/0000-0003-1952-3680; Fabregat, Juan/0000-0002-5986-9347 NR 50 TC 18 Z9 19 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 FEB 1 PY 1997 VL 284 IS 4 BP 859 EP 868 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WH887 UT WOS:A1997WH88700010 ER PT J AU Barry, DT AF Barry, DT TI Acoustic myography SO MUSCLE & NERVE LA English DT Letter ID SKELETAL-MUSCLE; SOUND PRODUCTION; FREQUENCIES; VIBRATIONS; FATIGUE; FROG RP Barry, DT (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,ASTRONAUT OFF,CODE CB,2101 NASA RD 1,HOUSTON,TX 77058, USA. NR 12 TC 4 Z9 4 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0148-639X J9 MUSCLE NERVE JI Muscle Nerve PD FEB PY 1997 VL 20 IS 2 BP 251 EP 252 PG 2 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA WG633 UT WOS:A1997WG63300025 PM 9040672 ER PT J AU Fawcett, PJ Agustsdottir, AM Alley, RB Shuman, CA AF Fawcett, PJ Agustsdottir, AM Alley, RB Shuman, CA TI The Younger Dryas termination and North Atlantic Deep Water Formation: Insights from climate model simulations and Greenland ice cores SO PALEOCEANOGRAPHY LA English DT Article ID LAST DEGLACIATION; ISOTOPIC PALEOTHERMOMETER; BOREHOLE TEMPERATURES; SNOW ACCUMULATION; RECORDS; PRECIPITATION; CIRCULATION; ATMOSPHERE; EVENT; HOLOCENE AB Results from the GISP2 and GRIP ice cores show that the termination of the Younger Dryas (YD) climate event in Greenland was a large and extremely fast climate change. A reinitiation of North Atlantic Deep Water formation following a shutdown, and its associated winter release of heat to the atmosphere, has been suggested as the most likely cause of this climate transition. To test this idea, two general circulation model experiments using GENESIS have been completed for YD time (12,000 calendar years ago): one with low heat flux in the Nordic Seas (10 W/m(2), deep water shutdown) and one with high Nordic Sea heat flux (300 W/m(2), active deep water formation). Comparison of Greenland climate differences between these experiments with the ice core records shows that when deep water is turned on, much of the YD termination warming is achieved. The increase in precipitation is underestimated because of a model tendency to overestimate summertime precipitation, which obscures the dominantly wintertime response to the specified forcing. The winter storm track shift toward Greenland contributes much of the climate change at the YD termination. C1 UNIV TORONTO, DEPT PHYS, TORONTO, ON, CANADA. PENN STATE UNIV, DEPT GEOSCI, UNIVERSITY PK, PA 16802 USA. PENN STATE UNIV, CTR EARTH SYST SCI, UNIVERSITY PK, PA 16802 USA. NASA, GODDARD SPACE FLIGHT CTR, OCEANS & ICE BRANCH, GREENBELT, MD 20771 USA. NR 46 TC 82 Z9 84 U1 2 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 EI 1944-9186 J9 PALEOCEANOGRAPHY JI Paleoceanography PD FEB PY 1997 VL 12 IS 1 BP 23 EP 38 DI 10.1029/96PA02711 PG 16 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA WD891 UT WOS:A1997WD89100003 ER PT J AU Dubois, T Jauberteau, F Zhou, Y AF Dubois, T Jauberteau, F Zhou, Y TI Influences of subgrid scale dynamics on resolvable scale statistics in large-eddy simulations SO PHYSICA D-NONLINEAR PHENOMENA LA English DT Article ID NAVIER-STOKES TURBULENCE; ISOTROPIC TURBULENCE; ENERGY-TRANSFER; FLOWS; VISCOSITY AB Recently, the epsilon-expansion and recursive renormalization group (RNG) theories as well as approximate inertial manifolds (AIM) have been exploited as means of systematically modeling subgrid scales in large-eddy simulations (LES). Although these theoretical approaches are rather complicated mathematically, their key approximations can be investigated using direct numerical simulations (DNS). In fact, the differences among these theories can be traced to whether they retain or neglect interactions between the subgrid-subgrid and subgrid-resolvable scales. In this paper, we focus on the influence of these two interactions on the evolution of the resolvable scales in LES: the effect(A) which keeps only the interactions between the small and large scales; and, the effect(B) which, on the other hand, keeps only the interactions among the subgrid-subgrid scales. The performance of these models is analyzed using the velocity fields of the direct numerical simulations. Specifically, our comparison is based on the analysis of the energy and enstrophy spectra, as well as higher-order statistics of the velocity and velocity derivatives. We found that the energy spectrum and higher-order statistics for the simulations with the effect(A) (referred to, hereafter, as model(A)) are in very good agreement with the filtered DNS. The comparison between the computations with effect(B) (referred to, hereafter, as model(B)) and the filtered DNS, however, is not satisfactory. Moreover, the decorrelation between the filtered DNS and model(A) is much slower than that of the filtered DNS and model(B). Therefore, we conclude that the model(A), taking into account the interactions between the subgrid and resolvable scales, is a faithful subgrid model for LES for the range of Reynolds numbers considered. C1 CNRS, F-63177 CLERMONT FERRAND, FRANCE. NASA, LANGLEY RES CTR, INST COMP APPLICAT SCI & ENGN, HAMPTON, VA 23681 USA. RP Dubois, T (reprint author), UNIV CLERMONT FERRAND, LAB MATH APPLIQUEES, F-63177 CLERMONT FERRAND, FRANCE. NR 35 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD FEB 1 PY 1997 VL 100 IS 3-4 BP 390 EP 406 DI 10.1016/S0167-2789(96)00191-1 PG 17 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA WF928 UT WOS:A1997WF92800010 ER PT J AU Halicioglu, T AF Halicioglu, T TI Properties of diamond and diamond-like clusters in nanometric dimensions SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH LA English DT Article AB Material properties for small clusters of nanometric dimensions were investigated. Calculations were carried out for spherical diamond and diamond-like particles containing over 1000 carbon atoms. Variations in the average cohesive energy, the excess surface energy and in the stiffness value were investigated as a function of the cluster size. Furthermore, energetic stabilities for spherical 3D clusters of carbon (in diamond-like atomic arrangements) were analyzed and compared with stabilities of other carbon clusters with lower dimensionalities. RP Halicioglu, T (reprint author), NASA,AMES RES CTR,THERMOPHYS INST,MS 230-3,MOFFETT FIELD,CA 94035, USA. NR 9 TC 7 Z9 7 U1 0 U2 1 PU AKADEMIE VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0370-1972 J9 PHYS STATUS SOLIDI B JI Phys. Status Solidi B-Basic Res. PD FEB PY 1997 VL 199 IS 2 BP 345 EP 350 DI 10.1002/1521-3951(199702)199:2<345::AID-PSSB345>3.0.CO;2-1 PG 6 WC Physics, Condensed Matter SC Physics GA WL404 UT WOS:A1997WL40400005 ER PT J AU James, GK Slevin, JA Shemansky, DE McConkey, JW Bray, I Dziczek, D Kanik, I Ajello, JM AF James, GK Slevin, JA Shemansky, DE McConkey, JW Bray, I Dziczek, D Kanik, I Ajello, JM TI Optical excitation function of H(1s-2p) produced by electron impact from threshold to 1.8 keV SO PHYSICAL REVIEW A LA English DT Article ID ATOMIC-HYDROGEN; CROSS-SECTIONS; LYMAN-ALPHA; INTERMEDIATE ENERGIES; EXTREME ULTRAVIOLET; SCATTERING; TRANSITIONS; COLLISIONS; SPECTRUM; MOLECULES AB The optical excitation function of prompt Lyman-alpha radiation, produced by electron impact on atomic hydrogen, has been measured over the extended energy range from threshold to 1.8 keV. Measurements were obtained in a crossed-beams experiment using both magnetically confined and electrostatically focused electrons in collision with atomic hydrogen produced by an intense discharge source. A vacuum-ultraviolet monochromator system was used to measure the emitted Lyman-alpha radiation. The absolute H(1s-2p) electron impact excitation cross section was obtained from the experimental optical excitation function by normalizing to the accepted optical oscillator strength, with corrections for polarization and cascade. Our data are significantly different from the earlier experimental results of R. L. Long et at, J. Res. Natl. Bur. Stand. Sect. A 72A, 521 (1968) and J. F. Williams, J. Phys. B 9, 1519 (1976); 14, 1197 (1981), which are limited to energies' below 200 eV. Statistical and known systematic uncertainties in our data range from +/-4% near threshold to +/-2% at 1.8 keV. Multistate coupling affecting the shape of the excitation function up to 1 keV impact energy is apparent in both the present experimental data and present theoretical results obtained with convergent close-coupling (CCC) theory. This shape function effect leads to an uncertainty in absolute cross sections at the 10% level in the analysis of the experimental data. The derived optimized absolute cross sections are within 7% of the CCC calculations over the 14 eV-1.8 keV range. The present CCC calculations converge on the Bethe-Fano profile for H(1s-2p) excitation at high energy. For this reason agreement with the CCC values to within 3% is achieved in a nonoptimal normalization of the experimental data to the Bethe-Fano profile. The fundamental H(1s-2p) electron impact cross section is thereby determined to an unprecedented accuracy over the 14 eV - 1.8 keV energy range. C1 ST PATRICKS COLL,DEPT EXPT PHYS,MAYNOOTH,KILDARE,IRELAND. UNIV SO CALIF,DEPT AEROSP ENGN,LOS ANGELES,CA 90089. UNIV WINDSOR,DEPT PHYS,WINDSOR,ON N9B 3P4,CANADA. FLINDERS UNIV S AUSTRALIA,ELECT STRUCT MAT CTR,ADELAIDE,SA 5001,AUSTRALIA. NICHOLAS COPERNICUS UNIV,INST PHYS,PL-87100 TORUN,POLAND. RP James, GK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Bray, Igor/B-8586-2009; Dziczek, Dariusz/G-3620-2014 OI Bray, Igor/0000-0001-7554-8044; NR 51 TC 15 Z9 15 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB PY 1997 VL 55 IS 2 BP 1069 EP 1087 DI 10.1103/PhysRevA.55.1069 PG 19 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WH919 UT WOS:A1997WH91900033 ER PT J AU Stern, DP AF Stern, DP TI Reprint pact proposed for saving time, effort when reusing figures SO PHYSICS TODAY LA English DT Letter RP Stern, DP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD FEB PY 1997 VL 50 IS 2 BP 11 EP & DI 10.1063/1.881667 PG 2 WC Physics, Multidisciplinary SC Physics GA WG436 UT WOS:A1997WG43600003 ER PT J AU Evans, DL Plaut, JJ Stofan, ER AF Evans, DL Plaut, JJ Stofan, ER TI Overview of the spaceborne imaging Radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) missions SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID INTERFEROMETRY AB Thr Spaceborne Imaging Radar-C/X-band synthetic Aperture Radar (SIR-C/X-SAR), the most advanced imaging radar system to have flown in Earth orbit, was carried in the cargo bay of the Space Shuttle Endeavour in April and October 1994. SIR-C/X-SAR simultaneously recorded data at three wavelengths (L-, C-, and X-bands; 23.5 cm, 5.8 cm, and 3.1 cm, respectively). In addition, the full polarimetric scattering matric was obtained at L- and C-band over a variety of terrain and vegetation types. Scientists are using multifrequency, polarimetric SIR-C/X-SAR data in studies of geology, hydrology, ecology, oceanography, and radar remote sensing techniques. The October SIR-C/X-SAR flight also included acquisition of experimental repeat-pass interferometry data which have been used to generate digital elevation models els and to detect surface motions in volcanic, tectonic, and glacial terrains. Results from SIR-C/X-SAR clearly show the increased value of using multiparameter and interferometric capabilities to characterize Earth's surface and vegetation cover and to generate geophysical products compared with optical sensors or single-channel radars alone. (C) Elsevier Science Inc., 1997. RP Evans, DL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 42 TC 24 Z9 27 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 135 EP 140 DI 10.1016/S0034-4257(96)00152-6 PG 6 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800001 ER PT J AU Rignot, E Salas, WA Skole, DL AF Rignot, E Salas, WA Skole, DL TI Mapping deforestation and secondary growth in Rondonia, Brazil, using imaging radar and thematic mapper data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID FOREST BIOMASS; SATELLITE DATA; LAND-USE; TROPICAL DEFORESTATION; AMAZON; CLASSIFICATION; BACKSCATTER; VEGETATION AB Excellent data on deforestation have been obtained in the tropics with the use of high-resolution optical sensors. Yet, several problems remain. Cloud cover creates data gaps that limit the possibility of complete and frequent assessments, and secondary growth is not well characterized. Active microwave sensors could complement these sensors because they operate independently of cloud cover and smoke and can detect differences in woody biomass and forest structure associated with various stages of forest clearing and regrowth. An example of comparison and synergy between the two techniques is discussed here. Polarimetric, C- (5.6 cm) and L-band (24 cm) frequency, radar data gathered in October 1994 by NASA's Spaceborne Imaging Radar C, on a test site southeast of the city of Porto Velho, in the state of Rondonia, Brazil are analyzed in conjunction with one 1993 Landsat Thematic Mapper (TM) scene, a 9-year time series of Satellite pour l'observation de la Terre (SPOT) XS data, two Japan Earth Resources Satellite (JERS-1) radar images from 1994 and 1995, and a field visit conducted in 1995. The C-band radar data are found to be of limited utility for mapping deforestation. At L-band multiple polarizations are required to obtain a reliable classification. The single polarization, L-band, single date, JERS-1 data underestimate the extent of deforestation, especially during the wet season. With multiple polarizations, sit classes of land cover including one level of regrowth, are mapped with 90% accuracy, but intermediate regrowth 5-8 years of age is not well separated from the forest. The Landsat TM data identify deforested areas better but provide less information on residual woody biomass levels. Combining the two classifications, seven classes of land cover including two levels of regrowth are mapped with 93% accuracy. The results show that the deforestation rate for 1994 was 1.7%. Large variations in residual woody biomass are detected among new clearings. Half of the total deforested land is in some stage of regrowth, but most of it is less than 5 years old. Secondary growth is therefore a significant form of land use that is recleared quickly. (C) Elsevier Science Inc., 1997. C1 UNIV NEW HAMPSHIRE,INST STUDY EARTH OCEANS & SPACE,DURHAM,NH 03824. RP Rignot, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 NR 35 TC 90 Z9 93 U1 2 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 167 EP 179 DI 10.1016/S0034-4257(96)00150-2 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800004 ER PT J AU Saatchi, SS Soares, JV Alves, DS AF Saatchi, SS Soares, JV Alves, DS TI Mapping deforestation and land use in Amazon rainforest by using SIR-C imagery SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SATELLITE DATA; FORESTS; EXTENT; BRAZIL AB In this paper, the potential use of spaceborne polarimetric synthetic aperture radar (SAR) data in mapping land-cover types and monitoring deforestation in tropics is studied. Here, the emphasis is placed on several clearing practices and forest regeneration that can be characterized by using the sensitivity of SAR channels to vegetation biomass and canopy structure. A supervised Bayesian classifier designed for SAR signal statistics is employed to separate five classes: primary forest, secondary forest, pasture-crops, quebradao, and disturbed forest. The L- and C-band polarimetric SAR data acquired during the shuttle imaging radar-C (SIR-C)/X-SAR space-shuttle mission in 1994 are used as input data to the classifier The results are verified by field observation and comparison with the Landsat data acquired in August of 1994. The SAR data can delineate these five classes with approximately 72% accuracy. The confusion arises when separating old secondary forests from primary forest and the young ones from pasture-crops. It is shown that Landsat and SAR data carry complementary information about the vegetation structure that, when used in synergism, may increase the classification accuracy over secondary forest regrowth. When the number of land-cover types was reduced to three classes including primary forest, pasture-crops, and regrowth-disturbed forest, the accuracy of classification increased to 87%. A dimensionality analysis of the classifier showed that the accuracy can be further improved to 92% by reducing the feature space to L-band HH and HV channels. Comparison of SIR-C data acquired in April (wet period) and October (dry period) indicates that multitemporal data can be used for monitoring deforestation; however the data acquired during the wet season are not suitable for accurate land-cover classification. (C)Elsevier Science Inc., 1997. C1 INST NACL PESQUISAS ESPACIAIS,SAO PAULO,BRAZIL. RP Saatchi, SS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. RI SOARES, Joao/D-2576-2014; Alves, Diogenes/K-6882-2014 OI SOARES, Joao/0000-0003-3880-0006; Alves, Diogenes/0000-0003-0559-0671 NR 31 TC 71 Z9 76 U1 1 U2 15 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 191 EP 202 DI 10.1016/S0034-4257(96)00153-8 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800006 ER PT J AU Ranson, KJ Sun, GQ AF Ranson, KJ Sun, GQ TI An evaluation of AIRSAR and SIR-C/X-SAR images for mapping northern forest attributes in Maine, USA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SYNTHETIC-APERTURE RADAR; ERS-1 SAR; CLASSIFICATION; BIOMASS; MULTIFREQUENCY; ECOSYSTEMS; LACUNARITY; TEXTURE AB In previous work by the authors, multifrequency, polarimetric airborne synthetic aperture radar (AIRSAR) data were used to characterize forest categories and biomass density of a forest area in Maine, USA. This study area was included as a test site for ecological studies during the Spaceborne Imaging Radar C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) missions in 1994. The SIR-C/X-SAR missions provided the first opportunity for Earth scientists to receive multifrequency and multipolarization SAR data from space from a single platform. During the Space Radar Laboratory missions in April and October 1994, images from AIRSAR and SIR-C/X-SAR were acquired for the same areas within a few days of each other. In this paper, the capabilities of AIRSAR and SIR-C/X-SAR images for characterizing a northern hardwood-boreal transitional forest were evaluated and compared. The use of multiple frequency, polarimetric information to produce forest-cover classification, biomass estimates, and forest spatial pattern analysis were investigated. The results from SIR-C/X-SAR compared with those from AIRSAR were generally similar despite different available frequency (C-band, L-band, X-band vs. C-band, L-band P-band) and resolution (25.0 m vs. 8.3 m). AIRSAR data better enabled the mapping of stands of hardwood and mixed: forests than did SIR-C/X-SAR data. However, SIR-C/X-SAR produced better classification results for conifer forest stands. There was no great benefit from using higher resolution for classification except for forest stands in which there were mixtures of species (i.e., hardwood and softwood). A comparison of the image data also showed that both instruments could provide reasonable estimates of biomass density up to about 15 kg/m(2). At higher biomass levels, both AIRSAR and SIR-C showed the well-known biomass saturation effect. The average biomass densities determined from the AIRSAR and SIR-C images were reasonably close at 9.7 kg/m(2) and 9.0 kg/m(2), respectively. Finally, spatial character of the image data was examined by using perimeter and area relations and lacunarity analysis. The results were consistent between. the two instruments and showed that the forest opening patterns were self-similar for openings greater than about 3 ha. (C)Elsevier Science Inc. 1997. C1 SCI SYST & APPL INC,LANHAM,MD. RP Ranson, KJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,BIOSPHER SCI BRANCH,GREENBELT,MD 20771, USA. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 34 TC 45 Z9 46 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 203 EP 222 PG 20 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800007 ER PT J AU Jameson, AR Li, FK Durden, SL Haddad, ZS Holt, BM Fogarty, T Im, E Moore, RK AF Jameson, AR Li, FK Durden, SL Haddad, ZS Holt, BM Fogarty, T Im, E Moore, RK TI SIR-C/X-SAR observations of rain storms SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SYNTHETIC-APERTURE RADAR; SEA; ATTENUATION; BACKSCATTER; FOOTPRINTS AB The spaceborne imaging radar-C, X-band synthetic aperture radar observations of rain storms are the first multipolarization and multifrequency observations of precipitation from space. In addition to numerous, often dramatic images of severe weather systems obtained by forming a synthetic aperture in the usual side-looking attitude, several data takes were performed while the radar antennas were parallel to the ground and the radar beams were pointing at nadir. These opportunities coincided with the passage of the Shuttle over Tropical Cyclone Odille in the southern Indian Ocean during the first flight and over Typhoon Seth in the western Pacific during the second flight. The resulting observations, or more appropriately, the resulting measurements, demonstrate for the first time the capability of a spaceborne multifrequency multipolarization microwave radar system to quantify precipitation rates, to detect hydrometeor phase, and to classify rain type. (C)Elsevier Science Inc., 1997. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. RJH SCI,ALEXANDRIA,VA. UNIV KANSAS,LAWRENCE,KS 66045. NR 32 TC 33 Z9 33 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 267 EP 279 DI 10.1016/S0034-4257(96)00159-9 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800012 ER PT J AU Wang, JR Hsu, A Shi, JC ONeill, PE Engman, ET AF Wang, JR Hsu, A Shi, JC ONeill, PE Engman, ET TI A comparison of soil moisture retrieval models using SIR-C measurements over the Little Washita River watershed SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID MICROWAVE BACKSCATTER DEPENDENCE; SURFACE-ROUGHNESS; BARE SOIL AB SIR-C L-band measurements over the Little Washita River watershed in Chickasha, Oklahoma during 11-17 April 1994 have been analyzed for studying the change of soil moisture in the region. Two algorithms developed recently for estimation of moisture content in bare soil were applied to these measurements and the results were compared with those sampled on the ground. There is a good agreement between the values of soil moisture estimated by either one of the algorithms and those measured from ground sampling for bare or sparsely vegetated fields. The standard error from this comparison is on the order of 0.05-0.06 cm(3)/cm(3), which is comparable to that expected from a regression between backscattering coefficients and measured soil moisture. Both algorithms provide a poor estimation of soil moisture or fail to give solutions to areas covered with moderate or fail to give solutions to areas covered with moderate or dense vegetation. Even for bare soils the number of pixels that bear no numerical solution from the application of either one of the two algorithms to the data is not negligible. Results from using one of these algorithms indicate that the fraction of these pixels becomes larger as the bare soils become drier. The other algorithm generally gives a larger fraction of these pixels when the fields are vegetation-covered. The implication and impact of these features are discussed in this article. (C)Elsevier Science Inc., 1997. C1 SCI SYST & APPL INC,LANHAM,MD. UNIV CALIF SANTA BARBARA,INST COMPUTAT EARTH SYST SCI,SANTA BARBARA,CA 93106. RP Wang, JR (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,CODE 675,GREENBELT,MD 20771, USA. RI O'Neill, Peggy/D-2904-2013 NR 26 TC 52 Z9 55 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 308 EP 320 DI 10.1016/S0034-4257(96)00145-9 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800015 ER PT J AU Guo, HD Liao, JJ Wang, CL Wang, C Farr, TG Evans, DL AF Guo, HD Liao, JJ Wang, CL Wang, C Farr, TG Evans, DL TI Use of multifrequency, multipolarization shuttle imaging radar for volcano mapping in the Kunlun Mountains of western China SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID LAVA FLOWS; FIELD; CALIFORNIA; ROCKS AB A group of volcanoes northeast of Aksayqin Lake, in the western Kunlun Mountains, China, have been identified on multifrequency, multipolarization spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) images. Field observations made on the volcanic morphology and terrain features are described in this paper. Analysis of single-band, single-polarization radar backscatter coefficients (sigma(o)) shows that LHV best discriminates the two types of lava flows (pahoehoe and aa lavas), alluvium, and bedrock. The factors affecting the radar backscattering coefficient also are analyzed. Finally, this paper presents K-Ar isotopic ages of volcanic samples collected in the field and discusses the volcanic samples collected in the field and discusses the volcanism in the area. (C)Elsevier Science Inc., 1997. C1 CALTECH,JET PROP LAB,PASADENA,CA. RP Guo, HD (reprint author), CHINESE ACAD SCI,INST REMOTE SENSING APPLICAT,BEIJING 100101,PEOPLES R CHINA. OI Farr, Thomas/0000-0001-5406-2096 NR 31 TC 6 Z9 9 U1 1 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB PY 1997 VL 59 IS 2 BP 364 EP 374 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA WQ318 UT WOS:A1997WQ31800018 ER PT J AU Jakosky, BM Jones, JH AF Jakosky, BM Jones, JH TI The history of Martian volatiles SO REVIEWS OF GEOPHYSICS LA English DT Review ID SNC METEORITES; ISOTOPIC COMPOSITION; NOBLE-GASES; WEATHERING PRODUCTS; MASS FRACTIONATION; AQUEOUS ALTERATION; OXYGEN ISOTOPES; IMPACT EROSION; SULFUR-RICH; EETA 79001 AB The behavior of water and other volatiles on Mars is key to understanding the evolution of the climate. The early climate played a fundamental role in producing the observed surface morphology and possibly in enabling the existence of an early biosphere. Geochemical and isotopic data can be used to infer the history of volatiles. On the basis of the isotopic data from the atmosphere and from components of the surface (as measured in meteorites that come from Mars), there appear to be at least two reservoirs of volatiles, one that has undergone exchange with the atmosphere and has been isotopically fractionated, and a second that is unfractionated and may represent juvenile gases. The fractionation of the atmospheric component has occurred primarily through the escape of gas to space. In addition, the atmospheric gases have mixed substantially with crustal reservoirs of volatiles. Such exchange may have occurred in aqueous or hydrothermal environments. The history of escape to space, as driven by the properties of the Sun through time, is consistent with the surface geomorphology. Together, they suggest an early environment that was substantially different from the present one and the evolution through time to a colder, dryer climate. C1 UNIV COLORADO, DEPT GEOL SCI, BOULDER, CO 80309 USA. NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. RP UNIV COLORADO, ATMOSPHER & SPACE PHYS LAB, CAMPUS BOX 392, BOULDER, CO 80309 USA. NR 101 TC 91 Z9 91 U1 3 U2 16 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 FEB PY 1997 VL 35 IS 1 BP 1 EP 16 DI 10.1029/96RG02903 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WJ454 UT WOS:A1997WJ45400001 ER PT J AU Toon, OB Zahnle, K Morrison, D Turco, RP Covey, C AF Toon, OB Zahnle, K Morrison, D Turco, RP Covey, C TI Environmental perturbations caused by the impacts of asteroids and comets SO REVIEWS OF GEOPHYSICS LA English DT Review ID CRETACEOUS-TERTIARY BOUNDARY; TUNGUSKA METEOR FALL; K-T BOUNDARY; NUCLEAR WINTER; EARTHS ATMOSPHERE; CHICXULUB CRATER; SHOCKED QUARTZ; K/T BOUNDARY; ACID-RAIN; SHOEMAKER-LEVY-9 AB We review the major impact-associated mechanisms proposed to cause extinctions at the Cretaceous-Tertiary geological boundary. We then discuss how the proposed extinction mechanisms may relate to the environmental consequences of asteroid and comet impacts in general. Our chief goal is to provide relatively simple prescriptions for evaluating the importance of impacting objects over a range of energies and compositions, but we also stress that there are many uncertainties. We conclude that impacts with energies less than about 10 Mt are a negligible hazard. For impacts with energies above 10 Mt and below about 10(4) Mt (i.e., impact frequencies less than one in 6 x 10(4) years, corresponding to comets and asteroids with diameters smaller than about 400 m and 650 m, respectively), blast damage, earthquakes, and fires should be important on a scale of 10(4) or 10(5) km(2), which corresponds to the area damaged in many natural disasters of recent history. However, tsunami excited by marine impacts could be more damaging, flooding a kilometer of coastal plain over entire ocean basins. In the energy range of 10(4)-10(5) Mt (intervals up to 3 x 10(5) years, corresponding to comets and asteroids with diameters up to 850 m and 1.4 km, respectively) water vapor injections and ozone loss become significant on the global scale. In our nominal model, such an impact does not inject enough submicrometer dust into the stratosphere to produce major adverse effects, but if a higher fraction of pulverized rock than we think likely reaches the stratosphere, stratospheric dust (causing global cooling) would also be important in this energy range. Thus 10(5) Mt is a lower limit where damage might occur beyond the experience of human history. The energy range from 10(5) to 10(6) Mt (intervals up to 2 x 10(6) years, corresponding to comets and asteroids up to 1.8 and 3 km diameter) is transitional between regional and global effects. Stratospheric dust, sulfates released from within impacting asteroids, and soot from extensive wildfires sparked by thermal radiation from the impact can produce climatologically significant global optical depths of the order of 10. Moreover, the ejecta plumes of these impacts may produce enough NO from shock-heated air to destroy the ozone shield. Between 10(6) and 10(7) Mt (intervals up to 1.5 x 10(7) years, corresponding to comets and asteroids up to 4 and 6.5 km diameter), dust and sulfate levels would be high enough to reduce light levels below those necessary for photosynthesis. Ballistic ejecta reentering the atmosphere as shooting stars would set fires over regions exceeding 10(7) km(2), and the resulting smoke would reduce light levels even further. At energies above 10(7) Mt, blast and earthquake damage reach the regional scale (10(6) km(2)). Tsunami cresting to 100 m and flooding 20 km inland could sweep the coastal zones of one of the world's ocean basins. Fires would be set globally. Light levels may drop so low from the smoke, dust, and sulfate as to make vision impossible. At energies approaching 10(9) Mt (>10(8) years) the ocean surface waters may be acidified globally by sulfur from the interiors of comets and asteroids. The Cretaceous-Tertiary impact in particular struck evaporate substrates that very likely generated a dense, widespread sulfate aerosol layer with consequent climatic effects. The combination of all of these physical effects would surely represent a devastating stress on the global biosphere. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. UNIV CALIF LOS ANGELES,INST GEOPHYS & PLANETARY PHYS,LOS ANGELES,CA 90024. LAWRENCE LIVERMORE NATL LAB,ENVIRONM PROGRAMS,LIVERMORE,CA 94550. UNIV CALIF LOS ANGELES,DEPT ATMOSPHER SCI,LOS ANGELES,CA 90095. NR 116 TC 223 Z9 233 U1 8 U2 99 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD FEB PY 1997 VL 35 IS 1 BP 41 EP 78 DI 10.1029/96RG03038 PG 38 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WJ454 UT WOS:A1997WJ45400003 ER PT J AU MacDonald, IR Reilly, JF Chu, JS Olivier, D AF MacDonald, IR Reilly, JF Chu, JS Olivier, D TI NR-1: Deep-ocean introduction of new laser line scanner SO SEA TECHNOLOGY LA English DT Article ID HYDROCARBON SEEP COMMUNITIES; GULF-OF-MEXICO; CONTINENTAL-SLOPE; NORTHERN GULF C1 NASA,HOUSTON,TX. NORTHROP CORP,UNDERWATER LASER DIV,ANNAPOLIS,MD. NAVSUB BASE NEW LONDON,GROTON,CT. RP MacDonald, IR (reprint author), TEXAS A&M UNIV,GEOCHEM & ENVIRONM RES GRP,COLLEGE STN,TX 77843, USA. NR 14 TC 4 Z9 4 U1 0 U2 1 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD FEB PY 1997 VL 38 IS 2 BP 59 EP 64 PG 6 WC Engineering, Ocean SC Engineering GA WJ299 UT WOS:A1997WJ29900008 ER PT J AU Fahr, HJ Fichtner, H Scherer, K AF Fahr, HJ Fichtner, H Scherer, K TI The influence of the local interstellar medium on the solar wind dynamics in the inner heliosphere SO SPACE SCIENCE REVIEWS LA English DT Review ID PICK-UP IONS; VELOCITY DISTRIBUTION-FUNCTIONS; MODIFIED STELLAR WINDS; COSMIC-RAY MEDIATION; TERMINATION SHOCK; STEADY-STATE; HYBRID SIMULATIONS; OUTER HELIOSPHERE; GLOBAL PROCESSES; GALACTIC WINDS AB The consequences of the interaction between the solar wind and the local interstellar medium for the wind region enclosed by the heliospheric shock are reviewed. After identifying the principal mechanisms to influence the dynamics of the solar wind, an approach allowing the simultaneous incorporation of neutral atoms, pick-up ions, cosmic rays and energetic electrons into a multifluid model of the expanding wind plasma is outlined. The effects of these particle species are discussed in detail, with special emphasis on the electron component which behaves more like a quasi-static hot gas rather than an expanding fluid. This electron gas is effectively trapped within a three-dimensional trough of a circumsolar electric potential whose outer fringes are possibly determined by the density distribution of anomalous cosmic rays. The electrons are proven to be a globally structered component of great importance for the solar wind momentum flow contributing to a triggering of the solar wind dynamics by asymmetric interstellar boundary conditions. Finally, the consequences for the relative motion of the Sun and the local interstellar medium as well as for the solar system as a whole are described. C1 UNIV MARYLAND, INST PHYS SCI & TECHNOL, COLLEGE PK, MD 20742 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Fahr, HJ (reprint author), UNIV BONN, INST ASTROPHYS & EXTRATERR FORSCH, HUGEL 71, D-53121 BONN, GERMANY. NR 157 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD FEB PY 1997 VL 79 IS 3-4 BP 659 EP 708 DI 10.1023/A:1004931725533 PG 50 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WT118 UT WOS:A1997WT11800001 ER PT J AU Criminale, WO Lasseigne, DG Jackson, TL AF Criminale, WO Lasseigne, DG Jackson, TL TI Vortex perturbation dynamics SO STUDIES IN APPLIED MATHEMATICS LA English DT Article ID 3-DIMENSIONAL INSTABILITY; STRAINED VORTICES; STABILITY; FLOW AB An initial value approach is used to examine the dynamics of perturbations introduced into a vortex under strain. Both the basic vortex considered and the perturbations are taken as three-dimensional. An explicit solution for the time evolution of the vorticity perturbations is given for arbitrary initial vorticity. Analytical solutions for the resulting velocity components are found when the initial vorticity is assumed to be localized. For more general initial vorticity distributions, the velocity components are determined numerically. It is found that the variation in the radial direction of the initial vorticity disturbance is the most important factor influencing the qualitative behavior of the solutions. Transient growth in the magnitude of the velocity components is found to be directly attributable to the compactness of the initial vorticity. C1 OLD DOMINION UNIV,DEPT MATH & STAT,NORFOLK,VA 23529. UNIV WASHINGTON,SEATTLE,WA 98195. NASA,LANGLEY RES CTR,HAMPTON,VA 23665. NR 8 TC 2 Z9 2 U1 0 U2 0 PU BLACKWELL PUBLISHERS PI CAMBRIDGE PA 350 MAIN STREET, STE 6, CAMBRIDGE, MA 02148-5023 SN 0022-2526 J9 STUD APPL MATH JI Stud. Appl. Math. PD FEB PY 1997 VL 98 IS 2 BP 99 EP 120 DI 10.1111/1467-9590.00042 PG 22 WC Mathematics, Applied SC Mathematics GA WL031 UT WOS:A1997WL03100001 ER PT J AU Potter, CS Klooster, SA AF Potter, CS Klooster, SA TI Global model estimates of carbon and nitrogen storage in litter and soil pools: Response to changes in vegetation quality and biomass allocation SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID EASTERN NORTH-AMERICA; CLIMATE-CHANGE; TRANSIENT-RESPONSE; PONDEROSA PINE; CO2; ECOSYSTEMS; FOREST; PRODUCTIVITY; SIMULATION; BIOSPHERE AB Changes in plant production, structure, and tissue composition are primary drivers for terrestrial biogeochemistry under future environmental conditions. Consequently, there is a need for process-oriented assessment of the potential global importance of vegetation controls over extended periods of C and N sequestration in terrestrial ecosystems. In this study, plant litter quality (lignin content) and carbon allocation to woody tissues are used as surrogates for testing the hypothetical effects of vegetation change on C and N cycles. We tested the CASA (Carnegie-Ames-Stanford approach) biosphere model, which uses global gridded (1 degrees) satellite imagery on a monthly time interval to simulate seasonal patterns in net ecosystem carbon balance and near steady-state C/N storage in detritus and soils. Under contemporary ''reference'' settings, combined organic matter storage (litter plus surface soil to ca. 30 cm depth) for C and N is estimated highest in tropical and boreal forest ecosystem zones, and in cultivated ecosystems. The worldwide C:N ratio (by weight) for standing litter plus surface soil organic matter (SOM) is estimated at 23. About 14% of the projected global pool of 1327 Pg (10(15) g) soil C resides in ''modern'' form, in the sense that this proportion is in near-steady state exchange with plant production and decomposition on time scales of several decades. Likewise, about 12% of the projected global pool of 104 Pg soil N is in modern form. Sensitivity tests treated litter quality and allocation effects independently from other direct effects of changes in climate, atmospheric CO2 levels, and primary production. For forested ecosystems, the model predicts that a hypothetical 50% decrease in litter lignin concentration would result in a long-term net loss of about 10% C from surface litter and soil organic matter pools. A 50% decrease in C allocation to woody tissues would invoke approximately the same net loss of C as a 50% decrease in litter lignin. With respect to nitrogen, the 50% downward adjustment in litter allocation to woody tissues may increase both the estimated net N mineralization rates and SLOW N pool by approximately 9% on a global basis. This pattern is consistent with an overall increase in N available for cycling, which is affected by the fraction of relatively N-poor to N-rich litter inputs. For comparison to the effects of these surrogate changes in vegetation tissue composition, model response to a globally uniform increase in surface air temperature of 1 degrees C is a net loss of 5% C from litter and SOM pools. RP Potter, CS (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS INC,MAIL STOP 242-4,MOFFETT FIELD,CA 94035, USA. NR 71 TC 48 Z9 54 U1 5 U2 39 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD FEB PY 1997 VL 49 IS 1 BP 1 EP 17 DI 10.1034/j.1600-0889.49.issue1.1.x PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WH483 UT WOS:A1997WH48300001 ER PT J AU Verghese, P Stone, LS AF Verghese, P Stone, LS TI Spatial layout affects speed discrimination SO VISION RESEARCH LA English DT Article DE segmentation; speed perception; temporal frequency; perceived speed; occlusion; motion; area MT ID TEMPORAL VISUAL AREA; PERCEPTION FOLLOWING LESIONS; MOTION PERCEPTION; DIRECTION; VELOCITY; CONTRAST; MONKEY; MT; ORIENTATION; RESPONSES AB We address a surprising result in a previous study of speed discrimination with multiple moving gratings: discrimination thresholds decreased when the number of stimuli was increased, but remained unchanged when the area of a single stimulus was increased [Verghese & Stone (1995). Vision Research, 35, 2811-2823]. In this study, we manipulated the spatial- and phase relationship between multiple grating patches to determine their effect on speed discrimination thresholds, In a fusion experiment, we merged multiple stimulus patches, in stages, into a single patch, Thresholds increased as the patches were brought closer and their phase relationship was adjusted to be consistent with a single patch. Thresholds increased further still as these patches were fused into a single patch. In a Jission experiment, we divided a single large patch into multiple patches by superimposing a cross with luminance equal to that of the background. Thresholds decreased as the large patch was divided into quadrants and decreased further as the quadrants were maximally separated. However, when the cross luminance was darker than the background, it was perceived as an occluder and thresholds, on average, were unchanged from that for the single large patch. A control experiment shows that the observed trend in discrimination thresholds is not due to the differences in perceived speed of the stimuli. These results suggest that the parsing of the visual image into entities affects the combination of speed information across space, and that each discrete entity effectively provides a single independent estimate of speed. Copyright (C) 1997 Published by Elsevier Science Ltd. C1 NASA, AMES RES CTR, FLIGHT MANAGEMENT & HUMAN FACTORS DIV, MOFFETT FIELD, CA 94035 USA. NR 35 TC 20 Z9 20 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0042-6989 J9 VISION RES JI Vision Res. PD FEB PY 1997 VL 37 IS 4 BP 397 EP 406 DI 10.1016/S0042-6989(96)00155-1 PG 10 WC Neurosciences; Ophthalmology SC Neurosciences & Neurology; Ophthalmology GA WG187 UT WOS:A1997WG18700005 PM 9156171 ER PT J AU Lorenz, RD McKay, CP Lunine, JI AF Lorenz, RD McKay, CP Lunine, JI TI Photochemically driven collapse of Titan's atmosphere SO SCIENCE LA English DT Article ID SURFACE; MODEL; EQUILIBRIUM; CLIMATE; LIQUID; MARS AB Saturn's giant moon Titan has a thick (1.5 bar) nitrogen atmosphere, which has a temperature structure that is controlled by the absorption of solar and thermal radiation by methane, hydrogen, and organic aerosols into which methane is irreversibly converted by photolysis. Previous studies of Titan's climate evolution have been done with the assumption that the methane abundance was maintained against photolytic depletion throughout Titan's history, either by continuous supply from the interior or by buffering by a surface or near surface reservoir. Radiative-convective and radiative-saturated equilibrium models of Titan's atmosphere show that methane depletion may have allowed Titan's atmosphere to cool so that nitrogen, its main constituent, condenses onto the surface, collapsing Titan into a Triton-like frozen state with a thin atmosphere. C1 NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Lorenz, RD (reprint author), UNIV ARIZONA,DEPT PLANETARY SCI,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA. RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 30 TC 61 Z9 61 U1 0 U2 6 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JAN 31 PY 1997 VL 275 IS 5300 BP 642 EP 644 DI 10.1126/science.275.5300.642 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WF077 UT WOS:A1997WF07700031 PM 9005844 ER PT J AU Folkner, WM Preston, RA Border, JS Navarro, J Wilson, WE Oestreich, M AF Folkner, WM Preston, RA Border, JS Navarro, J Wilson, WE Oestreich, M TI Earth-based radio tracking of the Galileo probe for Jupiter wind estimation SO SCIENCE LA English DT Article ID BALLOONS AB Although the Galileo probe was designed to communicate only to the orbiter, the probe radio signal was detected at two Earth-based radio observatories where the signal was a billion times weaker. The measured signal frequency was used to derive a vertical profile of the jovian zonal wind speed, Due to the mission geometry, the Earth-based wind estimates are less sensitive to descent trajectory errors than estimates based on probe-orbiter Doppler measurements. The two estimates of wind profiles agree qualitatively; both show high wind speeds at all depths sampled. C1 NATL RADIO ASTRON OBSERV,SOCORRO,NM 87801. CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. RP Folkner, WM (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 21 TC 23 Z9 23 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JAN 31 PY 1997 VL 275 IS 5300 BP 644 EP 646 DI 10.1126/science.275.5300.644 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WF077 UT WOS:A1997WF07700032 ER PT J AU Kaljevic, I Patnaik, SN Hopkins, DA AF Kaljevic, I Patnaik, SN Hopkins, DA TI Treatment of initial deformations in the Integrated Force Method SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID FINITE-ELEMENT ANALYSIS AB A new force finite element formulation, termed the Integrated Force Method, has been developed in recent years for the structural analysis. In the Integrated Force Method all independent forces are treated as unknown variables which are calculated by simultaneously imposing the force equilibrium and strain compatibility. The Integrated Force Method is extended in this study for the treatment of initial strains. Initial strains are incorporated into compatibility conditions through the vector of initial deformations. A general expression for the vector of initial deformations is derived by discretizing the expression for the complementary potential energy of the structure. Two special cases of initial strains are analyzed in detail: (i) thermal strains and (ii) support settlements. The vector of initial deformations due to thermal loadings is derived by introducing expressions for thermal strains into the general expression, and that due to support settlements is derived directly by equating the work done by external and internal forces, respectively. Two example problems with available analytical solutions are solved using the present developments. A good agreement of results with analytical solutions is observed. C1 AYT CORP,BROOKPARK,OH 44142. OHIO AEROSP INST,CLEVELAND,OH 44142. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. NR 11 TC 4 Z9 4 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD JAN 30 PY 1997 VL 140 IS 3-4 BP 281 EP 289 DI 10.1016/S0045-7825(96)01093-6 PG 9 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA WA921 UT WOS:A1997WA92100005 ER PT J AU Banerjea, A Good, BS AF Banerjea, A Good, BS TI Avalanche in adhesion at metal interfaces SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article ID EQUIVALENT-CRYSTAL THEORY; MULTILAYER RELAXATION; SURFACE ENERGIES; MICROSCOPY; DEFECTS AB Simulations have shown that as two metal surfaces approach each other, the surface layers can avalanche together when the rigid interfacial spacing falls below a critical distance. This is accompanied by a discontinuous decrease in the adhesive energy. Here we present an examination of this phenomenon for the bce metals Fe and W using the Equivalent Crystal Theory. In order to identify the circumstances under which avalanche might be inhibited, the effect of loss of registry between the two surfaces is investigated in detail. The avalanche is inhibited when the two surfaces are sufficiently far out of registry and when only a few layers near the surface are allowed to relax. As the relaxing slabs get thicker a sharp avalanche reappears. However, as the loss of registry increases the energy released in the avalanche decreases. C1 NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Banerjea, A (reprint author), SN BOSE NATL CTR BASIC SCI,JD BLOCK,CALCUTTA 700091,W BENGAL,INDIA. NR 17 TC 3 Z9 3 U1 0 U2 3 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD JAN 30 PY 1997 VL 11 IS 3 BP 315 EP 335 DI 10.1142/S0217979297000344 PG 21 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA WE161 UT WOS:A1997WE16100006 ER PT J AU Chipot, C Wilson, MA Pohorille, A AF Chipot, C Wilson, MA Pohorille, A TI Interactions of anesthetics with the water-hexane interface. A molecular dynamics study SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; ATOMIC CHARGES; MONTE-CARLO; NUCLEIC-ACIDS; LIQUID WATER; FORCE-FIELD; ENERGY; MICELLES; SURFACE; APPROXIMATION AB The free energy profiles characterizing the transfer of nine solutes across the liquid-vapor interfaces of water and hexane and across the water-hexane interface were calculated from molecular dynamics simulations. among the solutes were n-butane and three of its halogenated derivatives, as well as three halogenated cyclobutanes. The two remaining molecules, dichlorodifluoromethane and 1,2-dichloroperfluorethane, belong to series of halo-substituted methanes and ethanes. described in previous studies (J. Chem. Phys. 1996, 104, 3760; Chem. Phys. 1996, 204, 337). Each series of molecules contains structurally similar compounds that differ greatly in anesthetic potency. The accuracy of the simulations was tested by comparing the calculated and the experimental foe energies of solvation of all nine compounds in water and in hexane, in addition, the calculated and the measured surface excess concentrations of n-butane at the water liquid-vapor interface were compared. In all cases, good agreement with experimental results was found. At the water-hexane interface, the free energy profiles for polar molecules exhibited significant interfacial minima, whereas the profiles for nonpolar molecules did not. The existence of these minima was interpreted in terms of a balance between the free energy contribution arising from solute-solvent interactions and the work to form a cavity that accommodates the solute. These two contributions change monotonically, but oppositely, across the interface. The interfacial solubilities of the solutes, obtained from the free energy profiles, correlate very well with their anesthetic potencies. This is the case even when the Meyer-Overton hypothesis, which predicts a correlation between anesthetic potency and solubility in oil, fails. C1 NASA, AMES RES CTR, EXOBIOL BRANCH, MOFFETT FIELD, CA 94035 USA. UNIV CALIF SAN FRANCISCO, DEPT PHARMACEUT CHEM, SAN FRANCISCO, CA 94143 USA. FU NIGMS NIH HHS [GM47818-01] NR 67 TC 67 Z9 68 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JAN 30 PY 1997 VL 101 IS 5 BP 782 EP 791 DI 10.1021/jp961513o PG 10 WC Chemistry, Physical SC Chemistry GA WL110 UT WOS:A1997WL11000014 PM 11542402 ER PT J AU Ohsaka, K Chung, SK Rhim, WK Holzer, JC AF Ohsaka, K Chung, SK Rhim, WK Holzer, JC TI Densities of Si determined by an image digitizing technique in combination with an electrostatic levitator SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLTEN SILICON; RANGE AB We have determined the densities of Si in the liquid, rho(l)(T), and solid, rho(s)(T), states as a function of temperature, T, by employing an image digitizing technique and numerical calculation methods in combination with an electrostatic levitator. The obtained density data can be fitted with the following equations: rho(l)(T) = rho(l)(T-m) - 1.71 x 10(-4)(T-T-m) - 1.61 x 10(-7)(T- T-m)(2)(g/cm(3)); rho(s)(T) = rho(s)(T-m) - 2.63 x 10(-5)(T- T-m)(g/cm(3)), where T-m is the melting point, 1687 K, and rho(l)(T-m) and rho(s)(T-m) are 2.580 and 2.311 (g/cm(3)), respectively. The error involved in the determination is estimated to be +/- 0.006 (g/cm(3)). The rho(l)(T) value smoothly varies through T-m and does not indicate a reported anomalous density variation. The rho(l)(T-m) value is 2% larger than the literature value and the coefficient of the linear temperature dependence is approximately half of a reported value. The rho(s)(T-m) value closely agrees with the literature value. (C) 1997 American Institute of Physics. C1 MEMC ELECT MAT INC,ST PETERS,MO 63376. RP Ohsaka, K (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 13 TC 26 Z9 26 U1 2 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 27 PY 1997 VL 70 IS 4 BP 423 EP 425 DI 10.1063/1.118317 PG 3 WC Physics, Applied SC Physics GA WE457 UT WOS:A1997WE45700007 ER PT J AU Considine, GD AF Considine, GD TI Modeling the diurnal variability in cloud microphysics in boundary layer clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE STRATOCUMULUS LAYER; SENSITIVITY; ASTEX AB The purpose of this study is to understand and model the diurnal cycle in the microphysics of boundary layer clouds that has been inferred from recent remote sensing studies. To assess the modeled diurnal variation in cloud drop size, a one-dimensional cloud microphysics model is initialized with dynamical conditions that are typical of the contrast between daytime and nighttime clouds. The model-generated microphysics show a shift in droplet sizes from day to night that is consistent with that observed in satellite retrievals. The results indicate that the diurnal cycle in droplet size results from the shift in dynamical structure associated with the cloud becoming decoupled from the subcloud boundary layer during the day, along with an associated decrease in cloud-top entrainment. The effect of decoupling on drop size is also enhanced by a decreased concentration of activated droplets at cloud base associated with the characteristically smaller vertical updraft velocities for the decoupled clouds. RP NASA, LANGLEY RES CTR, MS 401B, HAMPTON, VA 23681 USA. NR 27 TC 6 Z9 6 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 27 PY 1997 VL 102 IS D2 BP 1717 EP 1726 DI 10.1029/96JD02997 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE650 UT WOS:A1997WE65000003 ER PT J AU Jin, Y Rossow, WB AF Jin, Y Rossow, WB TI Detection of cirrus overlapping low-level clouds SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; UPPER-AIR OBSERVATIONS; COMBINATION; STATISTICS; RADIATION; LAYER; HIRS; VAS AB A multispectral method is proposed to detect two-layer cloud systems with an optically thin (tau < 1.0) upper level (Pc < 600 mbar) cloud layer over a lower (600 mbar < Pc less than or equal to 900 mbar) cloud layer of tau > 1.0, with at least 100-mbar separation. The method uses the results from different high-resolution infrared radiometer sounder (HIRS) channel combinations assuming a single cloud layer in the CO2-Slicing technique and is valid over both land and ocean. Two months of HIRS data (July 1989 and January 1990) have been analyzed with this method. Globally (excluding regions poleward of 60 degrees) for HIRS field of view (FOV) (about 17 km at nadir) the fraction of such two-layer cloudiness is 25.5% over land and 32.0% over ocean for July 1989 and is 17.8% over land and 25.6% over ocean for January 1990 (this is not the total fraction of two-layer systems). The global distribution patterns of two-layer cloudiness for these 2 months are also presented: the fraction of two-layer cloudiness is larger over ocean than over land; it is larger in the tropics and midlatitude storm zones and smaller in the subtropical zones and marine stratiform cloud regions; over land it is larger in the summer than in the winter at all latitudes; over ocean it is larger in the summer for the northern hemispheric eastern Pacific-region while is larger in the winter for all other regions. Qualitative comparisons to surface and upper air observations are also presented and are very encouraging. C1 NASA, GODDARD INST SPACE STUDIES, NEW YORK, NY 10025 USA. RP Jin, Y (reprint author), COLUMBIA UNIV, DEPT GEOSCI, 2800 BROADWAY, NEW YORK, NY 10025 USA. RI Rossow, William/F-3138-2015 NR 39 TC 31 Z9 32 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 27 PY 1997 VL 102 IS D2 BP 1727 EP 1737 DI 10.1029/96JD02996 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE650 UT WOS:A1997WE65000004 ER PT J AU Chambers, LH Wielicki, BA Evans, KF AF Chambers, LH Wielicki, BA Evans, KF TI Accuracy of the independent pixel approximation for satellite estimates of oceanic boundary layer cloud optical depth SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATIVE-TRANSFER; RADIANCE MEASUREMENTS; ATMOSPHERES; IRRADIANCE; GEOMETRY; ALBEDO; SHAPE AB A theoretical study has been conducted on the effects of cloud horizontal inhomogeneity on the retrieval of optical depth by remote sensing of visible reflectance. Forty-five Landsat scenes of oceanic boundary layer clouds provide a sampling of real cloud fields, including trade cumulus, open and closed cell broken stratocumulus, and solid stratocumulus. The spherical harmonic discrete ordinate method (SHDOM) radiative transfer model is used to calculate two-dimensional reflectances from subsampled cloud strips representing the Landsat scenes. The independent pixel approximation (IPA) is used to retrieve optical depth for comparison to the original input. Results for tau(IPA) versus tau(ref) are presented on scales from the Landsat pixel scale (28.5 m) to an imager pixel scale (6 km) to near mesoscale (60 km). The random error decreases as the averaging scale increases, but error due to inhomogeneity remains. At the 60 km scale the average error is about 6% for high Sun, 2% for low Sun. Individual scenes, however, have retrieved optical depth errors as high as 45% due to horizontal radiative transport. The ability to retrieve higher statistical moments of the frequency distribution of optical depth is also assessed. Sigma, (sigma), the standard deviation of tau, is retrieved quite well up to a point, then is underestimated due to the smoothing effect of horizontal radiative transport. The gamma function parameter nu, another measure of the width of the tau frequency distribution, is retrieved quite well over a wide range but with a systematic bias which varies with solar zenith angle, again due to horizontal radiative transport. A method is sought to reduce the optical depth retrieval error using a simple correction based on remotely sensed cloud properties. Of those considered, cloud physical aspect ratio (computed here from one possible relation which depends on properties obtainable from remote sensing) is found to be the most effective correction parameter. The aspect ratio correction reduces the retrieved optical depth bias error by 50 to 100% and the RMS error by 20 to 50%. Correction coefficients are presented at three solar zenith angles. This work is limited by its consideration of only single-level marine boundary layer clouds, assumptions of conservative scattering, constant cloud droplet size, no gas absorption or surface reflectance, and restriction to two-dimensional radiative transport. Future work will attempt to remove some of these limitations. The Landsat data used are also limited due to radiative smoothing. C1 UNIV COLORADO, PROGRAM ATMOSPHER & OCEAN SCI, BOULDER, CO 80309 USA. RP Chambers, LH (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MS 420, HAMPTON, VA 23681 USA. NR 32 TC 50 Z9 50 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 27 PY 1997 VL 102 IS D2 BP 1779 EP 1794 DI 10.1029/96JD02995 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE650 UT WOS:A1997WE65000007 ER PT J AU Canuto, VM Dubovikov, MS Dienstfrey, A AF Canuto, VM Dubovikov, MS Dienstfrey, A TI Turbulent convection in a spectral model SO PHYSICAL REVIEW LETTERS LA English DT Article ID THERMAL TURBULENCE; NUMBER AB New laboratory and numerical simulation data on turbulent convection have become available. We generalize a recent spectral model of turbulence, which was previously tested on a variety of homogeneous flows, to treat inhomogeneous flows so as to study thermal convection. The model has no adjustable constants. We recover the available data (for large aspect ratios). We further derive an analytic expression for the Nusselt number versus Rayleigh and Prandtl numbers (in the limit of negligible diffusion). RP Canuto, VM (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 14 TC 6 Z9 6 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 27 PY 1997 VL 78 IS 4 BP 662 EP 665 DI 10.1103/PhysRevLett.78.662 PG 4 WC Physics, Multidisciplinary SC Physics GA WV391 UT WOS:A1997WV39100025 ER PT J AU Canuto, VM Dubovikov, MS AF Canuto, VM Dubovikov, MS TI Physical regimes and dimensional structure of rotating turbulence SO PHYSICAL REVIEW LETTERS LA English DT Article ID ISOTROPIC TURBULENCE AB Numerical simulations of rotating turbulence have given rise to ''unexpected results'': An increasing Omega did not lead to the ''expected'' route to a 2D state. A recent model of turbulence leads to a new number N = K(nu Omega)(-1) (K and nu are turbulent kinetic energy and viscosity) so that DNS (direct numerical simulation) and LES (large eddy simulation) correspond to N < 1 and N > 1. In the first case, the energy cascade is suppressed, while in the second case there exists an inertial spectrum which is an equilibrium of quasi-2D-3D modes. With these ingredients, we reproduce DNS and LES data. RP Canuto, VM (reprint author), NASA,GODDARD INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 25 TC 17 Z9 17 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 27 PY 1997 VL 78 IS 4 BP 666 EP 669 DI 10.1103/PhysRevLett.78.666 PG 4 WC Physics, Multidisciplinary SC Physics GA WV391 UT WOS:A1997WV39100026 ER PT J AU Smith, DE Zuber, MT Neumann, GA Lemoine, FG AF Smith, DE Zuber, MT Neumann, GA Lemoine, FG TI Topography of the moon from the Clementine lidar SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SEA BEAM DATA; SEAFLOOR MORPHOLOGY; HARMONIC-ANALYSIS; FLOOR TOPOGRAPHY; VENUS TOPOGRAPHY; LASER ALTIMETRY; ROUGHNESS; PARAMETERS; RESOLUTION; EARTH AB Range measurements from the lidar instrument carried aboard the Clementine spacecraft have been used to produce an accurate global topographic model of the Moon. This paper discusses the function of the lidar; the acquisition, processing, and filtering of observations to produce a global topographic model; and the determination of parameters that define the fundamental shape of the Moon. Our topographic model; a 72nd degree and order spherical harmonic expansion of lunar radii, is designated Goddard Lunar Topography Model 2 (GLTM 2). This topographic field has an absolute vertical accuracy of approximately 100 m and a spatial resolution of 2.5 degrees. The field shows that the Moon can be described as a sphere with maximum positive and negative deviations of similar to 8 km, both occurring on the farside, in the areas of the Korolev and South Pole-Aitken (S.P.-Aitken) basins. The amplitude spectrum of the topography shows more power at longer wavelengths as compared to previous models, owing to more complete sampling of the surface, particularly the farside. A comparison of elevations derived from the Clementine lidar to control point elevations from the Apollo laser altimeters indicates that measured relative topographic heights generally agree to within similar to 200 m over the maria. While the major axis of the lunar gravity field is aligned in the Earth-Moon direction, the major axis of topography is displaced from this line by approximately 10 degrees to the east and intersects the farside 24 degrees north of the equator. The magnitude of impact basin topography is greater than the lunar flattening (similar to 2 km) and equatorial ellipticity (similar to 800 m), which imposes a significant challenge to interpreting the lunar figure. The floors of mare basins are shown to lie close to an equipotential surface, while the floors of unflooded large basins, except for S.P.-Aitken, lie above this equipotential. The radii of basin floors are thus consistent with a hydrostatic mechanism for the absence of significant farside maria except for S.P.-Aitken, whose depth and lack of mare require significant internal compositional and/or thermal heterogeneity. A macroscale surface roughness map shows that roughness at length scales of 10(1)-10(2) km correlates with elevation and surface age. C1 NASA,GODDARD SPACE FLIGHT CTR,SPACE GEODESY BRANCH,GREENBELT,MD 20771. JOHNS HOPKINS UNIV,DEPT EARTH & PLANETARY SCI,BALTIMORE,MD 21218. MIT,DEPT EARTH ATMOSPHER & PLANETARY SCI,CAMBRIDGE,MA 02139. RP Smith, DE (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,CODE 920,GREENBELT,MD 20771, USA. RI Lemoine, Frank/D-1215-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 80 TC 161 Z9 185 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JAN 25 PY 1997 VL 102 IS E1 BP 1591 EP 1611 DI 10.1029/96JE02940 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WG197 UT WOS:A1997WG19700001 ER PT J AU Bogard, DD AF Bogard, DD TI A reappraisal of the Martian Ar-36/Ar-38 ratio SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT Workshop on Mars Volatile Evolution CY FEB, 1996 CL LUNAR PLANETARY INST, HOUSTON, TX HO LUNAR PLANETARY INST ID NOBLE-GASES; SNC METEORITES; ORTHOPYROXENITE ALH84001; SHERGOTTITES; ORIGIN; MARS; ATMOSPHERE; GLASS; EETA-79001; EVOLUTION AB The currently used value of 4.1 +/- 0.2 for the Ar-36/Ar-38 isotopic ratio in the Martian atmosphere is reappraised, and a significantly lower ratio is suggested. Previous analyses of noble gases in impact glass from some Martian meteorites demonstrate that large quantities of Martian atmospheric gases were shock-emplaced into these samples. However, several observations indicate that this trapped Martian gas is composed of two components, one atmospheric and one probably from the Martian mantle. These observations include large variations in Ar-36/Ar-38 during stepwise gas release, variations in the Ar/Kr/Xe elemental ratios among Martian meteorites, and variations in the cosmogenic-corrected, trapped Ar-36/Ar-38 ratios over 3.5-4.3 among shock glass samples. Uncertainties in applied corrections for cosmogenic Ar cannot explain these variations. By assuming a range of reasonable values for Martian atmospheric and mantle Ar-40/Ar-36, the observed Ar-40/Ar-36 ratios in shock glass are used to correct for the mantle component and to derive a more precise ratio for the atmospheric component. Using this procedure, one obtains an upper limit for Martian atmospheric Ar-36/Ar-38 of 3.9, and a probable, but poorly defined range for Martian atmospheric Ar-36/Ar-38 of similar to 3.0-3.6. These lower ratios imply that the degree of mass fractionation during Ar loss from Mars' upper atmosphere is considerably larger than that previously calculated. RP Bogard, DD (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,PLANETARY SCI BRANCH,CODE SN4,HOUSTON,TX 77058, USA. NR 33 TC 38 Z9 38 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JAN 25 PY 1997 VL 102 IS E1 BP 1653 EP 1661 DI 10.1029/96JE02796 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WG197 UT WOS:A1997WG19700006 ER PT J AU Swindle, TD Jones, JH AF Swindle, TD Jones, JH TI The xenon isotopic composition of the primordial Martian atmosphere: Contributions from solar and fission components SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article; Proceedings Paper CT Workshop on Mars Volatile Evolution CY FEB, 1996 CL LUNAR PLANETARY INST, HOUSTON, TX HO LUNAR PLANETARY INST ID NOBLE-GASES; SNC METEORITES; ORIGIN; SHERGOTTITES; EVOLUTION; SYSTEM; FRACTIONATION; CHRONOLOGY; VOLATILES; KRYPTON AB Previous models of the evolution of the isotopic composition of Xe in the Martian atmosphere have little room for any Xe produced by fission of Pu-244, although there is a contribution from the decay of shorter-lived I-129. We find that the previously calculated ratios of I-derived to Pu-derived Xe can only be matched if Mars accreted very early and outgassing of I-derived Xe after atmospheric loss was much stronger than outgassing of Pu-derived Xe. Alternatively, we find that if we assume that primordial Xe on Mars had the isotopic composition of the solar wind, rather than the previously assumed chondritic Xe, a larger contribution from Pu-244 is allowed, and it is much easier to generate models of outgassing and atmospheric loss that match the present atmosphere. Furthermore, the isotopic composition of solar wind Xe matches that of the Chassigny meteorite (widely considered to represent a sample of Martian interior Xe), so it is not necessary to postulate separate sources of Xe for the interior and atmosphere of Mars. C1 NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058. RP Swindle, TD (reprint author), UNIV ARIZONA,LUNAR & PLANETARY LAB,DEPT PLANETARY SCI,TUCSON,AZ 85721, USA. NR 37 TC 22 Z9 22 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JAN 25 PY 1997 VL 102 IS E1 BP 1671 EP 1678 DI 10.1029/96JE03110 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WG197 UT WOS:A1997WG19700008 ER PT J AU Garvin, JB AF Garvin, JB TI Volcano instability on the Earth and other planets - McGuire,WJ, Jones,AP, Neuberg,J SO SCIENCE LA English DT Book Review RP Garvin, JB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 1 TC 0 Z9 0 U1 1 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JAN 24 PY 1997 VL 275 IS 5299 BP 496 EP 497 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WE257 UT WOS:A1997WE25700031 ER PT J AU Garvin, JB AF Garvin, JB TI Volcanoes of the solar system - Frankel,C SO SCIENCE LA English DT Book Review RP Garvin, JB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 1 TC 0 Z9 0 U1 1 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD JAN 24 PY 1997 VL 275 IS 5299 BP 496 EP 497 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WE257 UT WOS:A1997WE25700030 ER PT J AU Sellers, PJ Dickinson, RE Randall, DA Betts, AK Hall, FG Berry, JA Collatz, GJ Denning, AS Mooney, HA Nobre, CA Sato, N Field, CB Henderson-Sellers, A AF Sellers, PJ Dickinson, RE Randall, DA Betts, AK Hall, FG Berry, JA Collatz, GJ Denning, AS Mooney, HA Nobre, CA Sato, N Field, CB Henderson-Sellers, A TI Modeling the exchanges of energy, water, and carbon between continents and the atmosphere SO SCIENCE LA English DT Review ID GENERAL-CIRCULATION MODEL; SIMPLE BIOSPHERE MODEL; LAND-SURFACE; CLIMATE MODELS; TROPICAL DEFORESTATION; STOMATAL CONDUCTANCE; AMAZONIAN DEFORESTATION; CANOPY REFLECTANCE; JULY CIRCULATION; REGIONAL CLIMATE AB Atmospheric general circulation models used for climate simulation and weather forecasting require the fluxes of radiation, heat, water vapor, and momentum across the land-atmosphere interlace to be specified. These fluxes are calculated by submodels called land surface parameterizations. Over the last 20 years, these parameterizations have evolved from sim pie, unrealistic schemes into credible representations of the global soil-vegetation-atmosphere transfer system as advances in plant physiological and hydrological research, advances in satellite data interpretation, and the results of large-scale field experiments have been exploited. Some modem schemes incorporate biogeochemical and ecological knowledge and, when coupled with advanced climate and ocean models, will be capable of modeling the biological and physical responses of the Earth system to global change, for example, increasing atmospheric carbon dioxide. C1 UNIV ARIZONA, DEPT ATMOSPHER SCI, TUCSON, AZ 85721 USA. COLORADO STATE UNIV, DEPT ATMOSPHER SCI, FT COLLINS, CO 80523 USA. ATMOSPHER RES, PITTSFORD, VT 05763 USA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. CARNEGIE INST WASHINGTON, DEPT PLANT BIOL, STANFORD, CA 94305 USA. UNIV CALIF SANTA BARBARA, SCH ENVIRONM SCI & MANAGEMENT, SANTA BARBARA, CA 93106 USA. STANFORD UNIV, DEPT BIOL SCI, STANFORD, CA 94305 USA. INPE, CPTEC, BR-12630000 CACHOEIRA PAULISTA, SP, BRAZIL. JAPAN METEOROL AGCY, DIV NUMER PREDICT, CHIYODA KU, TOKYO 100, JAPAN. ROYAL MELBOURNE INST TECHNOL, BUNDOORA, VIC 3083, AUSTRALIA. RP Sellers, PJ (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, MAIL CODE CB, HOUSTON, TX 77058 USA. RI Berry, Joseph/B-8211-2009; Betts, Alan/H-5282-2011; Henderson-Sellers, Ann/H-5323-2011; collatz, george/D-5381-2012; Denning, Scott/F-4974-2011; Randall, David/E-6113-2011 OI Berry, Joseph/0000-0002-5849-6438; Denning, Scott/0000-0003-3032-7875; Randall, David/0000-0001-6935-4112 NR 104 TC 751 Z9 826 U1 21 U2 186 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 24 PY 1997 VL 275 IS 5299 BP 502 EP 509 DI 10.1126/science.275.5299.502 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WE257 UT WOS:A1997WE25700036 ER PT J AU Sigl, G Lee, SJ Schramm, DN Coppi, P AF Sigl, G Lee, SJ Schramm, DN Coppi, P TI Cosmological neutrino signatures for grand unification scale physics SO PHYSICS LETTERS B LA English DT Article DE neutrino astronomy; gamma-ray astrophysics; ultra-high energy cosmic rays ID ENERGY COSMIC-RAYS; TOPOLOGICAL DEFECTS; SPECTRUM; STRINGS; RADIATION; CUTOFF; SEARCH; WELL; FLUX; EYE AB Physics beyond the standard model might imply the cosmological production of particles with grand unification scale energies. Nucleons and gamma-rays from such processes are candidates for the cosmic rays observed beyond 100 EeV (10(20) eV). Using a new particle propagation code, we calculate the neutrino fluxes predicted by such scenarios if consistency with the observed cosmic ray flux and the universal gamma-ray background at 1-10GeV is required, Flux levels detectable by proposed km(3) scale neutrino observatories are allowed by these constraints. Bounds on or detection of a neutrino flux above similar to 1 EeV would allow neutrino astronomy to probe grand unification scale physics. C1 FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60510 USA. YALE UNIV, DEPT ASTRON, NEW HAVEN, CT 06520 USA. RP UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. OI Sigl, Guenter/0000-0002-4396-645X NR 56 TC 76 Z9 76 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD JAN 23 PY 1997 VL 392 IS 1-2 BP 129 EP 134 DI 10.1016/S0370-2693(96)01534-1 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WE566 UT WOS:A1997WE56600019 ER PT J AU Schwarz, GJ Hauschildt, PH Starrfield, S Baron, E Allard, F Shore, SN Sonneborn, G AF Schwarz, GJ Hauschildt, PH Starrfield, S Baron, E Allard, F Shore, SN Sonneborn, G TI Non-LTE model atmosphere analysis of the early ultraviolet spectra of Nova OS Andromedae 1986 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars, abundances; stars, individual, Nova OS And 1986; novae, cataclysmic variables; ultraviolet, stars ID RADIATIVE-TRANSFER; CLASSICAL NOVAE; DISTANCE SCALE; PHOTOMETRY; EVOLUTION; SHELLS AB We analyse the early, optically thick, ultraviolet spectra of Nova OS And 1986 using a grid of spherically symmetric, non-LTE, line-blanketed, expanding model atmospheres and synthetic spectra with the following set of parameters: 5000 less than or equal to T-model less than or equal to 60 000 K, solar abundances, rho proportional to r(-3), v(max) = 2000 km s(-1), L = 6 x 10(4) L., and a statistical or microturbulent velocity of 50 km s(-1). We use the synthetic spectra to estimate the model parameters corresponding to the observed IUE spectra. The fits to the observations are then iteratively improved by changing the parameters of the model atmospheres - in particular, T-model and the abundances - to arrive at the best fits to the optically thick pseudo-continuum and the features found in the IUE spectra. The IUE spectra show two different optically thick subphases. The earliest spectra, taken a few days after maximum optical light, show a pseudo-continuum created by overlapping absorption lines. The later observations, taken approximately 3 weeks after maximum light, show the simultaneous presence of allowed, semiforbidden and forbidden lines in the observed spectra. Analysis of these phases indicates that OS And 1986 had solar metallicities, except for Mg which showed evidence of being underabundant by as much as a factor of 10. We determine a distance of 5.1 kpc to OS And 1986, and derive a peak bolometric luminosity of similar to 5 x 10(4) L.. The computed nova parameters provide insights into the physics of the early outburst and explain the spectra seen by IUE. Lastly, we find evidence in the later observations for large non-LTE effects of Fe II which, when included, lead to much better agreement with the observations. C1 UNIV GEORGIA,DEPT PHYS & ASTRON,ATHENS,GA 30602. UNIV OKLAHOMA,DEPT PHYS & ASTRON,NORMAN,OK 73019. WICHITA STATE UNIV,DEPT PHYS,WICHITA,KS 67260. INDIANA UNIV,DEPT PHYS & ASTRON,S BEND,IN 46634. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP Schwarz, GJ (reprint author), ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287, USA. RI Baron, Edward/A-9041-2009 OI Baron, Edward/0000-0001-5393-1608 NR 41 TC 23 Z9 23 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 21 PY 1997 VL 284 IS 3 BP 669 EP 684 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WE368 UT WOS:A1997WE36800013 ER PT J AU Boogert, ACA Schutte, WA Helmich, FP Tielens, AGGM Wooden, DH AF Boogert, ACA Schutte, WA Helmich, FP Tielens, AGGM Wooden, DH TI Infrared observations and laboratory simulations of interstellar CH4 and SO2 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE infrared: ISM: lines and bands; ISM: molecules; ISM: abundances; ISM: dust: extinction; molecular data; stars: individual: W 33A ID POLYCYCLIC AROMATIC-HYDROCARBONS; SULFUR-DIOXIDE; SOLID CO; HIGH-RESOLUTION; CLOUDS; ICES; SPECTRA; SPECTROSCOPY; ABSORPTION; METHANE AB Interstellar CH4 may consume a fair amount of the carbon budget in dense molecular clouds, but probably less than CO, CH3OH, and CO2. However, it can only be observed at wavelength regions in the infrared that are heavily affected by the earth atmosphere. With new space and airborne missions (e.g. ISO, SOFIA) in mind we have studied the near infrared absorption spectra of solid and gaseous CH4. We obtained laboratory spectra of the nu(4) deformation mode (1302 cm(-1), 7.68 mu m) of solid CH4 in astrophysically relevant mixtures. We found that the peak position and width of this absorption band vary strongly as a function of molecular environment, compared to temperature and particle shape effects. Hence, observations of this feature will provide a powerful probe of the molecular composition of interstellar ices. Also the gas phase CH4 rovibrational spectrum of the same band has been calculated. Using observed physical conditions around the protostar W 33A, we show that unresolved gaseous CH4 lines are detectable (at the 2-5% level) at a resolution R > 1000, when the column density N greater than or equal to 10(16) cm(-2). An astrophysically relevant molecule with a very strong transition in the same wavelength regime, is SO2. We studied the nu(3) asymmetric stretching mode (1319 cm(-1), 7.58 mu m) of solid SO2 in several mixtures, revealing that the peak position, width and detailed profile of this band are very sensitive to the molecular environment. Besides probing the composition of ice mantles, observations of solid SO2 will provide important infer mation on the sulfur budget locked up in grain mantles, which is currently poorly known. We compare the laboratory and calculated spectra of CH4 and SO;! with previously published ground based spectra and new airborne observations of young stellar objects in the 7-8 mu m region. W 33A, NGC 7538 : IRS1 and 1RS9 show a feature near 7.68 mu m that is consistent with absorption by solid CH4 or the Q-branch of gaseous CH4. The column density of solid CH4 would be 0.3-4% of solid H2O, indicating that solid CH4 consumes 0.5 +/- 0.3% of the cosmic carbon abundance. A gaseous origin would imply a column density of at least this amount, being highly dependent on the assumed temperature of the absorbing gas. A second absorption feature is detected toward W 33A and NGC 7538 :IRS1 at 7.58 mu m. The peak position and width of this feature are consistent with the nu(3) mode of solid SO2 in a matrix of solid CH3OH or pure SO2. The derived column density is 0.1-1% of solid H2O, indicating that solid SO2 locks up 0.6-6% of the cosmic sulfur abundance. This study shows that 7-8 mu m spectroscopy of dense molecular clouds, using new airborne and space-based platforms, will provide valuable information on the composition of icy grain mantles and molecular cloud chemistry. C1 LEIDEN OBSERV, NL-2300 RA LEIDEN, NETHERLANDS. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Boogert, ACA (reprint author), KAPTEYN ASTRON INST, POB 800, NL-9700 AV GRONINGEN, NETHERLANDS. NR 63 TC 73 Z9 73 U1 1 U2 9 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN 20 PY 1997 VL 317 IS 3 BP 929 EP 941 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WG169 UT WOS:A1997WG16900038 ER PT J AU Turner, TJ George, IM Mushotzky, RF Nandra, K AF Turner, TJ George, IM Mushotzky, RF Nandra, K TI Deconvolution of the X-ray emission and absorption components in Centaurus A SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, individual (Centaurus A); X-rays, galaxies ID ROSAT; ASCA; LUMINOSITY; NUCLEUS; SPECTRA; DISK AB We present ROSAT HRI and PSPC plus ASCA X-ray observations of the radio galaxy Centaurus A. The HRI image reveals that the X-ray jet has remained constant in flux since the Einstein observation 15 years ago, while the nuclear flux has decreased by similar to 60%. The PSPC data allows the first detailed spatially resolved X-ray spectroscopy of the nucleus, jet, and diffuse emission in Cen A. The 0.1-2 keV spectrum of the nucleus is heavily absorbed, as expected. The jet can be described by a power law of photon index Gamma similar to 2.3, although thermal models cannot be ruled out. The presence of faint diffuse emission is confirmed, extending out to similar to 6 kpc from the nucleus. The spectrum of the diffuse emission can be modeled as two ''Raymond-Smith'' plasmas. A low-temperature component, kT = 0.29 keV, is consistent with emission from gas heated by stars, while the harder component may represent the contribution of galactic X-ray binary systems; the diffuse emission increases in intensity close to the galactic disk. The identification of these extended components makes it possible to separate the nuclear and diffuse contributions to the ASCA spectrum. The 0.6-10 keV nuclear spectrum is well modeled by a power-law continuum of photon index Gamma similar to 1.96, in good agreement with the ''canonical'' value for Seyfert 1 galaxies. Forty percent of the nuclear continuum is absorbed by a column density similar to 4 x 10(23) cm(-2), 59% is absorbed by a column similar to 1 x 10(23) cm(-2), and 1% is absorbed by a value close to the 21 cm Galactic line-of-sight column. The high degree of nuclear absorption is consistent with the circumnuclear molecular clouds whose existence is suggested by absorption measurements in a number of wave bands. The iron K alpha emission line observed appears broad; the best-fit Gaussian width implies an origin in material with velocities similar to 11,000 km s(-1), while the equivalent width is 114 +/- 18 eV. Both quantities are in good agreement with an origin in the circumnuclear absorbing material. RP Turner, TJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 660,GREENBELT,MD 20771, USA. NR 50 TC 64 Z9 65 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1997 VL 475 IS 1 BP 118 EP 133 DI 10.1086/303510 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WD179 UT WOS:A1997WD17900012 ER PT J AU Hollis, JM Lyon, RG Dorband, JE Feibelman, WA AF Hollis, JM Lyon, RG Dorband, JE Feibelman, WA TI Motion of the ultraviolet R Aquarii jet SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM, individual (R Aquarii); ISM, jets and outflows; techniques, image processing; ultraviolet, ISM ID RADIO-CONTINUUM; BINARY-SYSTEM; NEBULA; SPECTROSCOPY; EMISSION; HST AB We present evidence for subarcsecond changes in the ultraviolet (similar to 2550 Angstrom) morphology of the inner 5 arcseconds of the R Aqr jet over a 2 yr period. These data were taken with the Hubble Space Telescope (HST) Faint Object Camera (FOG) when the primary mirror flow was still affecting observations. Images of the R Aqr stellar jet were successfully restored to the original design resolution by completely characterizing the telescope-camera point spread function (PSF) with the aid of phase-retrieval techniques. Thus, a noise-free PSF was employed in the final restorations which utilized the maximum entropy method (MEM). We also present recent imagery obtained with the HST/FOC system after the COSTAR correction mission that provides confirmation of the validity of our restoration methodology. The restored results clearly show that the jet is flowing along the northeast (NE)-southwest (SW) axis with a prominent helical-like structure evident on the stronger NE side of the jet. Transverse velocities increase with increasing distance from the central source, providing a velocity range of 36-235 km s(-1). From an analysis of proper motions of the two major ultraviolet jet components, we detect an similar to 40.2 yr event separation of this apparent enhanced material ejection occurring probably at periastron which is consistent with the suspected similar to 44 yr binary period; this same analysis shows that the jet is undergoing nonlinear acceleration which suggests that the propulsive force probably results from magnetohydromagnetic effects. The restoration computations and the algorithms employed demonstrate that mining of flawed HST data can be scientifically worthwhile. C1 UNIV MARYLAND,CTR EXCELLENCE SPACE DATA & INFORMAT SCI,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,HIGH PERFORMANCE COMP BRANCH,GREENBELT,MD 20771. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP Hollis, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,DIV SPACE DATA & COMP,CODE 930,GREENBELT,MD 20771, USA. RI Lyon, Richard/D-5022-2012 NR 29 TC 15 Z9 15 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1997 VL 475 IS 1 BP 231 EP & DI 10.1086/303526 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WD179 UT WOS:A1997WD17900022 ER PT J AU Kucera, TA Dennis, BR Schwartz, RA Shaw, D AF Kucera, TA Dennis, BR Schwartz, RA Shaw, D TI Evidence for a cutoff in the frequency distribution of solar flares from small active regions SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun, activity; Sun, flares; Sun, X-rays, gamma rays ID PARAMETERS; AVALANCHES AB In this paper, we present evidence that active regions with small sunspot areas have an upper limit to the energy of the hares they produce. This result is consistent with predictions of the avalanche model of Lu et al. We used data from the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission to study differences in the frequency distributions of solar hares as grouped by active region characteristics. The active region parameters considered were the total sunspot area, the longitudinal extent, the Mount Wilson class, and the McIntosh class. We find that there are significantly fewer high count rate flares (greater than or similar to 10(4) counts s(-1) above 60 keV) from regions with small sunspot areas (0-500 microhemispheres) than would be expected from a power-law extrapolation from the frequency distribution of flares with peak rates greater than 50 counts s(-1) above 60 keV. This is not found in the distribution of flares produced by regions with large sunspot areas (600-3600 microhemispheres). Using our analysis of the data and the predictions of the avalanche model we calculated a limit to the energy of a flare that can be produced by an active region with given sunspot area. There are no statistically significant differences between the frequency distributions of flares with peak count rates greater than or similar to 10(3) counts s(-1) grouped according to the other region characteristics studied. We also find that, in all cases, large complex regions appear to produce a lower percentage of low-energy events than do smaller, simpler regions. It is possible that this effect is the result of biases against observations of low count rate flares and the determination of their locations. C1 NOAA,SOLAR ENVIRONM LAB,BOULDER,CO 80303. RP Kucera, TA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,CODE 682,GREENBELT,MD 20771, USA. RI Dennis, Brian/C-9511-2012; Kucera, Therese/C-9558-2012 NR 25 TC 41 Z9 41 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1997 VL 475 IS 1 BP 338 EP 347 DI 10.1086/303532 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WD179 UT WOS:A1997WD17900034 ER PT J AU Wahlgren, GM Johansson, SG Litzen, U Gibson, ND Cooper, JC Lawler, JE Leckrone, DS Engleman, R AF Wahlgren, GM Johansson, SG Litzen, U Gibson, ND Cooper, JC Lawler, JE Leckrone, DS Engleman, R TI Atomic data for the Re II UV 1 multiplet and the rhenium abundance in the HgMn-type star chi Lupi SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; line, identification; stars, abundances; stars, individual (chi Lupi); stars, peculiar; ultraviolet, stars ID OSCILLATOR-STRENGTHS; B-STAR; TRANSITION; ELEMENTS; DESIGN AB We report new laboratory spectroscopic analyses that have been conducted to acquire wavelength and oscillator strength data for lines of the Re II UV 1 multiplet. Wavelengths were determined to a sub-milliangstrom accuracy for the hyperfine and isotopic structure components from laboratory spectra obtained with the Lund VUV Fourier Transform Spectrometer. An absolute atomic transition probability is reported for Re II 2275.253 Angstrom, obtained from its upper level lifetime and an experimentally determined branching fraction. The radiative Lifetime of the z P-7(2)0 level was found to be 4.47 +/- 0.22 ns by the method of laser-induced fluorescence. With the new atomic data, synthetic spectra were generated to fit a Hubble Space Telescope Goddard High Resolution Spectrograph echelle mode spectrum of the chemically peculiar HgMn-type star chi Lupi. The weakness of the lambda 2275.253 Angstrom feature only allowed for the determination of an upper limit to the rhenium abundance, which was found to be consistent with the meteoritic value. Thus, in chi Lupi rhenium appears to be several orders of magnitude less abundant than the apparent surficial abundances of the slightly heavier elements Pt, Ay Hg, and Tl. C1 GHRS SCI TEAM,GSFC,GREENBELT,MD 20771. LUND UNIV,DEPT PHYS,S-22362 LUND,SWEDEN. UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. NR 29 TC 19 Z9 20 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1997 VL 475 IS 1 BP 380 EP 386 DI 10.1086/303539 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WD179 UT WOS:A1997WD17900038 ER PT J AU Stothers, RB Sillanpaa, A AF Stothers, RB Sillanpaa, A TI Test of periodicity in the quasar OJ 287 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; BL Lacertae objects, individual (OJ 287); quasars, individual (OJ 287) AB OJ 287 displays an apparent periodicity in its violent optical light variations. By applying a progressively brighter faint-magnitude cutoff of the data when performing time series analyses of the light curve, the best-fit period is found to increase from 11.7-12.1 yr (depending on the method used) to 12.4 yr (based on an analysis of only the times of light maximum). In comparison, the average time interval between large outbursts is 11.7 yr. The derived period exhibits noticeable instability, which cannot be caused by the very slow modulation of the light curve or by the double-peak structure of the light maxima. Moreover, the probability of obtaining such a periodicity by chance in the 105 years of past observation is at least 0.02. Nevertheless, arguments based on the observed repetition of structure in the light curve, combined with a binary black hole model, suggest that a real underlying periodicity does exist. C1 UNIV TURKU,TUORLA OBSERV,FIN-21500 PIIKKIO,FINLAND. RP Stothers, RB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,2880 BROADWAY,NEW YORK,NY 10025, USA. NR 16 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 1997 VL 475 IS 1 BP L13 EP L15 DI 10.1086/310465 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WD181 UT WOS:A1997WD18100004 ER PT J AU Lo, CP Quattrochi, DA Luvall, JC AF Lo, CP Quattrochi, DA Luvall, JC TI Application of high-resolution thermal infrared remote sensing and GIS to assess the urban heat island effect SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID EVAPOTRANSPIRATION; TEMPERATURES AB Day and night airborne thermal infrared image data at 5 m spatial resolution acquired with the 15-channel (0 . 45 mu m-12 . 2 mu m) Advanced Thermal and Land Applications Sensor (ATLAS) over Alabama, Huntsville on 7 September, 1994 were used to study changes in the thermal signatures of urban land cover types between day and night. Thermal channel number 13 (9 . 60 mu m-10 . 2 mu m) data with the best noise-equivalent temperature change (NE Delta T) of 0 . 25 degrees C after atmospheric corrections and temperature calibration were selected for use in this analysis. This research also examined the relation between land cover irradiance and vegetation amount, using the Normalized Difference Vegetation Index (NDVI), obtained by ratioing the difference and the sum of the red (channel number 3: 0 . 60-0 . 63 mu m) and reflected infrared (channel number 6: 0 . 76-0 . 90 mu m) ATLAS data. Based on the mean radiance values, standard deviations, and NDVI extracted from 351 pairs of polygons of day and night channel number 13 images for the city of Huntsville, a spatial model of warming and cooling characteristics of commercial, residential, agricultural, vegetation, and water features was developed using a GIS approach. There is a strong negative correlation between NDVI and irradiance of residential, agricultural and vacant/transitional land cover types, indicating that the irradiance of a land cover type is greatly influenced by the amount of vegetation present. The predominance of forests, agricultural, and residential uses associated with varying degrees of tree cover showed great contrasts with commercial and services land cover types in the centre of the city, and favours the development of urban heat islands. The high-resolution thermal infrared images match the complexity of the urban environment, and are capable of characterizing accurately the urban land cover types for the spatial modeling of the urban heat island effect using a GIS approach. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, EARTH SYST SCI DIV, GLOBAL HYDROL & CLIMATE CTR, HUNTSVILLE, AL 35812 USA. RP UNIV GEORGIA, DEPT GEOG, ATHENS, GA 30602 USA. NR 21 TC 196 Z9 246 U1 9 U2 73 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0143-1161 EI 1366-5901 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 1997 VL 18 IS 2 BP 287 EP 304 DI 10.1080/014311697219079 PG 18 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA WF605 UT WOS:A1997WF60500005 ER PT J AU Acker, JG Brown, CW Hine, AC AF Acker, JG Brown, CW Hine, AC TI The 'CORSAGE' programme: Continuous orbital remote sensing of archipelagic geochemical effects SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID CARBONATE-PERIPLATFORM SEDIMENTATION; SHALLOW-WATER FINES; RAPID OFF-BANK; VERTICAL TRANSPORT; DENSITY FLOWS; ATLANTIC-OCEAN; MECHANISM; ACCUMULATION; PACIFIC; RISE AB Current and pending oceanographic remote sensing technology allows the conceptualization of a programme designed to investigate ocean-island interactions that could induce short-term nearshore fluxes of particulate organic carbon and biogenic calcium carbonate from pelagic island archipelagoes. These events will influence the geochemistry of adjacent waters, particularly the marine carbon system. Justification and design are provided for a study that would combine oceanographic satellite remote sensing (visible and infrared radiometry, altimetry and scatterometry) with shore-based facilities. A programme incorporating the methodology outlined here would seek to identify the mechanisms that cause such events, assess their geochemical significance, and provide both analytical and predictive capabilities for observations on greater temporal and spatial scales. C1 NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,LAB HYDROSPHER PROC,GREENBELT,MD 20771. UNIV S FLORIDA,DEPT MARINE SCI,ST PETERSBURG,FL 33701. RP Acker, JG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HUGHES STX CORP,LAB HYDROSPHER PROC,CODE 970,GREENBELT,MD 20771, USA. RI Brown, Christopher/B-8213-2008 OI Brown, Christopher/0000-0002-9905-6391 NR 41 TC 2 Z9 2 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 1997 VL 18 IS 2 BP 305 EP 321 DI 10.1080/014311697219088 PG 17 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA WF605 UT WOS:A1997WF60500006 ER PT J AU Kondo, Y Sugita, T Salawitch, RJ Koike, M Deshler, T AF Kondo, Y Sugita, T Salawitch, RJ Koike, M Deshler, T TI Effect of Pinatubo aerosols on stratospheric NO SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFATE AEROSOLS; ARCTIC STRATOSPHERE; REACTIVE NITROGEN; CHLORINE RADICALS; DIURNAL-VARIATION; OZONE; HNO3; N2O5; O-3; SPACELAB-3 AB Concentrations of nitric oxide (NO), total reactive nitrogen (NOy), O-3, and aerosol were measured between 14 and 32 km on balloon platforms launched from Aire sur l'Adour (44 degrees N, 0 degrees W), France, on October 20 and November 6, 1992. Aerosol surface area has been deduced from the observed concentrations of aerosols with radii ranging from 0.18 to 0.7 mu m. On these days the surface area was enhanced due to the eruption of Mount Pinatubo, which occurred in June 1991. The data set is used to investigate the effect of heterogeneous reactions on sulfuric acid aerosol reducing NOx. A diurnal; photochemical model, which takes into account heterogeneous chemistry, is used to calculate the changes in the partitioning of reactive nitrogen in the altitude region between 18 and 32 km. The observed values of NO and NOx/NOy ratio are significantly lower than those calculated by the model without taking into account heterogeneous chemistry. The degree of reduction of NOx by heterogeneous reaction was observed to vary sensitively with surface area for values lower than 2 mu m(2)cm(-3). The net reduction of NOx by aerosol tended to saturate at surface area larger than 4 mu m(2)cm(-3). Observations of NO and NOx/NOy are shown to be in generally good agreement with theoretical values found using the same model but including heterogeneous chemistry, indicating that NOx was reduced primarily by the hydrolysis of N2O5 on sulfuric acid aerosol. C1 UNIV WYOMING, DEPT ATMOSPHER SCI, LARAMIE, WY 82071 USA. CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Kondo, Y (reprint author), NAGOYA UNIV, SOLAR TERR ENVIRONM LAB, TOYOKAWA, AICHI 442, JAPAN. RI Salawitch, Ross/B-4605-2009; Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012; OI Salawitch, Ross/0000-0001-8597-5832; Sugita, Takafumi/0000-0002-0508-7040 NR 40 TC 12 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1205 EP 1213 DI 10.1029/96JD03063 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500002 ER PT J AU Callis, LB Natarajan, M Lambeth, JD Boughner, RE AF Callis, LB Natarajan, M Lambeth, JD Boughner, RE TI On the origin of midlatitude ozone changes: Data analysis and simulations for 1979-1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC OZONE; HETEROGENEOUS CHEMISTRY; PINATUBO AEROSOLS; ANTARCTIC VORTEX; GLOBAL OZONE; MT-PINATUBO; DEPLETION; ERUPTION; TRENDS; PERTURBATION AB Satellite data show large declines in global (4.5%) and midlatitude (10%) ozone in the mid-1980s and during 1992 and 1993. Analyses of ozone, temperature, and aerosol records and two-dimensional chemical transport simulations have been carried out to develop an understanding of the causes of these changes. Simulations include contemporary homogeneous and heterogeneous chemistry. Also included are the effects of trace gas increases, dilution and denitrification associated with the Antarctic ozone destruction, solar cycle effects including relativistic electron precipitation (REP),variable diabatic transport fields and temperature, and variable sulfate aerosol surface area density and acidity. Simulated global and midlatitude ozone agree very well with observations for the entire period. Mid-1980s near-global ozone declines calculated by the model were found to be due to solar cycle (including REP) effects, -1.9%; volcanic effects, -1.5%; dilution effects, -1.1%; transport and temperature effects, -1%; and trace gas effects, -0.2%. The maximum effects of these different processes occur at different times. The observed 10% reductions in midlatitude ozone are reproduced in the simulations and are primarily due to 1 to 2-year transport and temperature variations. C1 SCI APPLICAT INT CORP, HAMPTON, VA 23666 USA. RP Callis, LB (reprint author), NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, MAIL STOP 401B, HAMPTON, VA 23681 USA. NR 47 TC 37 Z9 37 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1215 EP 1228 DI 10.1029/96JD03058 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500003 ER PT J AU Worden, H Beer, R Rinsland, CP AF Worden, H Beer, R Rinsland, CP TI Airborne infrared spectroscopy of 1994 western wildfires SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MOLECULAR DATABASE; BIOMASS FIRES; EMISSIONS; GASES; WATER AB In the summer of 1994 the 0.07 cm(-1) resolution infrared Airborne Emission Spectrometer (AES) acquired spectral data over two wildfires, one in central Oregon on August 3 and the other near San Luis Obispo, California, on August 15. The spectrometer was on board a NASA DC-8 research aircraft, flying at an altitude of 12 km. The spectra from both fires clearly show features due to water vapor, carbon dioxide, carbon monoxide, ammonia, methanol, formic acid, and ethylene at significantly higher abundance and temperature than observed in downlooking spectra of normal atmospheric and ground conditions. Column densities are derived for several species, End molar ratios are compared with previous biomass fire measurements. We believe that this is the first time such data have been acquired by airborne spectral remote sensing. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. RP Worden, H (reprint author), CALTECH, JET PROP LAB, MS 238-600, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 27 TC 53 Z9 55 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1287 EP 1299 DI 10.1029/96JD02982 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500009 ER PT J AU Lee, M Heikes, BG Jacob, DJ Sachse, G Anderson, B AF Lee, M Heikes, BG Jacob, DJ Sachse, G Anderson, B TI Hydrogen peroxide, organic hydroperoxide, and formaldehyde as primary pollutants from biomass burning SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CHEMISTRY; FIRES; LAYER AB Hydrogen peroxide, organic hydroperoxide species, and formaldehyde were found to be enhanced within biomass burning plumes during the Transport and Atmospheric Chemistry near the Equator - Atlantic (TRACE A) experiment. This enhancement could have resulted from direct emission by the fires or by secondary photochemical production. In this study, direct production of hydroperoxide and formaldehyde from biomass burning is proposed and examined through comparisons of hydroperoxide and formaldehyde measurements, obtained from three fire flights in TRACE A, with model estimates, with other measurement data, and with results from fire experiments at the University of Rhode Island (URI). For highest concentrations of hydroperoxide and formaldehyde, model predictions fall short of those observed, and an additional source is required. H2O2 and CH3OOH were noted to increase with CO and were significantly correlated with other measured species known to be produced from biomass burning. The enhancements of H2O2 and CH3OOH relative to CO were different between flights in which the relative enhancements of CO to CO2 were also different. The enhancement ratio of H2O2 and CH3OOH relative to CO was 1-5x10(-2) and 2-4x10(-3), respectively. CH2O was correlated with CO. The enhancement ratios of CH2O were determined in relation to both CO and CO2 for three flights and were 7-19x10(-3) and 3-5x10(-4), respectively. The correlations of CH2O with other measured combustion species were more significant than those of H2O2 and CH3OOH. To determine whether hydroperoxide and formaldehyde can be directly produced from biomass burning, simple biomass fire experiments were performed at URI. These species were observed to be clearly elevated in test biomass fires. These experiments present unequivocal evidence for the direct production of hydrogen peroxide and formaldehyde from biomass burning. The results from both TRACE A and our fire experiments also fit possible mechanisms of direct formation of hydroperoxide and formaldehyde in combustion processes. The atmospheric implication of the direct production of these species from biomass burning is their contribution to odd-hydrogen radical production, thereby affecting the oxidizing capacity of the atmosphere before O-3 would be photochemically developed. In TRACE A, odd-hydrogen radical production from the direct source of these species is estimated to be near 30% of the total radical production. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. HARVARD UNIV, CAMBRIDGE, MA 02138 USA. RP Lee, M (reprint author), UNIV RHODE ISL, GRAD SCH OCEANOG, CTR ATMOSPHER CHEM STUDY, NARRAGANSETT, RI 02882 USA. NR 36 TC 64 Z9 64 U1 3 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1301 EP 1309 DI 10.1029/96JD01709 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500010 ER PT J AU Lutman, ER Pyle, JA Chipperfield, MP Lary, DJ KilbaneDawe, I Waters, JW Larsen, N AF Lutman, ER Pyle, JA Chipperfield, MP Lary, DJ KilbaneDawe, I Waters, JW Larsen, N TI Three-dimensional studies of the 1991/1992 northern hemisphere winter using domain-filling trajectories with chemistry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT International Conference on Ozone in the Lower Stratosphere CY 1995 CL HALKIDIKI, GREECE SP European Commiss DG XII, WMO, NASA, NOAA, IOC, SPARC, LAP ID POLAR VORTEX; REACTIVE CHLORINE; RADIATION-FIELD; STRATOSPHERE; TROPOSPHERE; ATMOSPHERE; TWILIGHT; MODEL; OZONE; HNO3 AB We describe a new and computationally efficient technique for global three-dimensional modeling of stratospheric chemistry. This technique involves integrating a photochemical package along a large number of independent trajectories to produce a Lagrangian view of the atmosphere. Although Lagrangian chemical modeling with trajectories is an established procedure, this extension of integrating chemistry along a large number of domain-filling trajectories is a novel technique. This technique is complementary to three-dimensional Eulerian chemical transport modeling and avoids spurious mixing caused by low resolutions or diffusive transport schemes in these models. We illustrate the technique by studying the chlorine activation in the Arctic winter lower stratosphere. A photochemical model was integrated along large ensembles of calculated trajectories between 20 and 100 mbar for the 1991/1992 winter in order to produce a three-dimensional chemical picture. Large amounts of chlorine was activated at low altitudes (80 to 100 mbar) as well as altitudes near 50 mbar. This activated air was well contained at all levels, with little indication of mixing into lower latitudes. Model results for early January 1992 were compared to daily Microwave Limb Sounder (MLS) ClO observations at 465 K. The structure and evolution of the activated chlorine was well reproduced, giving faith in the technique, although absolute modeled ClO amounts were smaller than the MLS data. A larger number of domain-filling isentropic trajectories were also run at 475 K to produce a higher-resolution picture of vortex evolution in late January 1992. The model successfully reproduced the wave breaking events which characterized this period causing transport of activated air to lower latitudes. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. DANISH METEOROL INST, DK-2100 COPENHAGEN O, DENMARK. RP Lutman, ER (reprint author), UNIV CAMBRIDGE, CTR ATMOSPHER SCI, DEPT CHEM, LENSFIELD RD, CAMBRIDGE CB2 1EW, ENGLAND. RI Lary, David/A-6163-2010; Chipperfield, Martyn/H-6359-2013; Larsen, Niels/G-3145-2014 OI Chipperfield, Martyn/0000-0002-6803-4149; NR 36 TC 17 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1479 EP 1488 DI 10.1029/96JD00698 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500026 ER PT J AU Harris, NRP Ancellet, G Bishop, L Hofmann, DJ Kerr, JB McPeters, RD Prendez, M Randel, WJ Staehelin, J Subbaraya, BH VolzThomas, A Zawodny, J Zerefos, CS AF Harris, NRP Ancellet, G Bishop, L Hofmann, DJ Kerr, JB McPeters, RD Prendez, M Randel, WJ Staehelin, J Subbaraya, BH VolzThomas, A Zawodny, J Zerefos, CS TI Trends in stratospheric and free tropospheric ozone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article; Proceedings Paper CT International Conference on Ozone in the Lower Stratosphere CY 1995 CL HALKIDIKI, GREECE SP European Commiss DG XII, WMO, NASA, NOAA, IOC, SPARC, LAP ID RECORD LOW OZONE; NORTHERN-HEMISPHERE WINTER; NINO-SOUTHERN OSCILLATION; MT-PINATUBO; MOUNT-PINATUBO; SURFACE OZONE; VOLCANIC-ERUPTIONS; UNITED-STATES; NIMBUS-7 SBUV; UMKEHR DATA AB Current understanding of the long-term ozone trends is described. Of particular concern is an assessment of the quality of the available measurements, both ground and satellite based. Trends in total ozone have been calculated for the ground-based network and the combined data set from the solar backscatter ultraviolet (SBUV) instruments on Nimbus 7 and NOAA 11, At midlatitudes in the northern hemisphere the trends from 1979 to 1994 are significantly negative in all seasons and are larger in winter/spring (up to 7%/decade) than in summer/fall (about 3%/decade). Trends in the southern midlatitudes are also significantly negative in all seasons (3 to 6%/decade), but there is a smaller seasonal variation, In the tropics, trends are slightly-negative and at the edge of being significant at the 95% confidence level: these tropical trends are sensitive to the low ozone amounts observed near the end of the record and allowance must also be made for the suspected drift in the satellite calibration. The bulk of the midlatitude loss in the ozone column has taken place at altitudes between 15 and 25 km. There is disagreement on the magnitude of the reduction, with the SAGE I/II record showing trends as large as -20 +/- 8%/decade at 16-17 km and the ozonesondes indicating an average trend of -7 +/- 3%/decade in the northern hemisphere. (All uncertainties given in this paper are two standard errors or 95% confidence limits unless stated otherwise), Recent ozone measurements are described for both Antarctica and the rest of the globe, The sulphate aerosol resulting from the eruption of Mount Pinatubo in 1991 and dynamic phenomena seem to have affected ozone levels, particularly at northern midlatitudes and in the Antarctic vortex, However, the record low values observed were partly caused by the long-term trends and the effect on the calculated trends was less than 1.5%/decade. C1 UNIV CAMBRIDGE, CTR ATMOSPHER SCI, DEPT CHEM, CAMBRIDGE CB2 1HE, ENGLAND. UNIV PARIS 06, SERV AERON, CNRS, F-75252 PARIS, FRANCE. ALLIED SIGNAL INC, BUFFALO, NY 14210 USA. NOAA, ENVIRONM RES LABS, BOULDER, CO 80303 USA. ATMOSPHER ENVIRONM SERV, DOWNSVIEW, ON M3H 5T4, CANADA. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. UNIV CHILE, SANTIAGO, CHILE. NATL CTR ATMOSPHER RES, BOULDER, CO 80307 USA. ETH ZURICH, ZURICH, SWITZERLAND. PHYS RES LAB, AHMEDABAD 380009, GUJARAT, INDIA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, JULICH, GERMANY. NASA, LANGLEY RES CTR, HAMPTON, VA 23665 USA. UNIV THESSALONIKI, LAB ATMOSPHER PHYS, THESSALONIKI, GREECE. RP UNIV CAMBRIDGE, EUROPEAN OZONE RES COORDINATING UNIT, 14 UNION RD, CAMBRIDGE CB2 1HE, ENGLAND. RI McPeters, Richard/G-4955-2013; Volz-Thomas, Andreas/J-7223-2012; Randel, William/K-3267-2016; OI McPeters, Richard/0000-0002-8926-8462; Volz-Thomas, Andreas/0000-0003-3700-1667; Randel, William/0000-0002-5999-7162; Harris, Neil/0000-0003-1256-3006 NR 113 TC 84 Z9 87 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1997 VL 102 IS D1 BP 1571 EP 1590 DI 10.1029/96JD02440 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WE445 UT WOS:A1997WE44500035 ER PT J AU Barry, SR Bloomberg, JJ Huebner, WP AF Barry, SR Bloomberg, JJ Huebner, WP TI The effect of visual context on manual localization of remembered targets SO NEUROREPORT LA English DT Article DE allocentric; egocentric; manual localization; manual motor control; pointing; reference frames; sensorimotor integration; spatial localization; spatial memory; visual context ID MOVEMENTS; EYE; ORGANIZATION; HUMANS; SPACE AB THIS paper examines the contribution of egocentric cues and visual context to manual localization of remembered targets. Subjects pointed in the dark to the remembered position of a target previously viewed without or within a structured visual scene. Without a remembered visual context, subjects pointed to within 2 degrees of the target. The presence of a visual context with cues of straight ahead enhanced pointing performance to the remembered location of central but not off-center targets. Thus, visual context provides strong visual cues of target position and the relationship of body position to target location. Without a visual context, egocentric cues provide sufficient input for accurate pointing to remembered targets. C1 NASA,LYNDON B JOHNSON SPACE CTR,LIFE SCI RES LABS,HOUSTON,TX 77058. KRUG LIFE SCI INC,NEUROSCI LABS,HOUSTON,TX 77058. RP Barry, SR (reprint author), MT HOLYOKE COLL,DEPT BIOL SCI,S HADLEY,MA 01075, USA. NR 16 TC 14 Z9 14 U1 0 U2 3 PU RAPID SCIENCE PUBLISHERS PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8NH SN 0959-4965 J9 NEUROREPORT JI Neuroreport PD JAN 20 PY 1997 VL 8 IS 2 BP 469 EP 473 DI 10.1097/00001756-199701200-00019 PG 5 WC Neurosciences SC Neurosciences & Neurology GA WX340 UT WOS:A1997WX34000020 PM 9080431 ER PT J AU Liou, JC Malhotra, R AF Liou, JC Malhotra, R TI Depletion of the outer asteroid belt SO SCIENCE LA English DT Article ID SOLAR-SYSTEM; NEPTUNE; ORIGIN; ORBIT AB During the early history of the soar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region. C1 LUNAR & PLANETARY INST, HOUSTON, TX 77058 USA. RP NASA, LYNDON B JOHNSON SPACE CTR, SN3, HOUSTON, TX 77058 USA. OI Malhotra, Renu/0000-0002-1226-3305 NR 18 TC 44 Z9 44 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD JAN 17 PY 1997 VL 275 IS 5298 BP 375 EP 377 DI 10.1126/science.275.5298.375 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WC873 UT WOS:A1997WC87300042 ER PT J AU Leu, MT Timonen, RS Keyser, LF AF Leu, MT Timonen, RS Keyser, LF TI Kinetics of the heterogeneous reaction HNO3(g)+NaBr(s)<->HBr(g)+NaNO3(s) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID NITRIC-ACID; HYDROGEN-CHLORIDE; OZONE DEPLETION; SURFACE OZONE; ICE FILMS; BROMINE; AEROSOLS; STRATOSPHERE; CLOUD AB The kinetics of the heterogeneous reaction HNO3(g)+NaBr(s)<->HBr(g)+NaNO3(s) has been investigated at 296 K using a fast-flow reactor coupled to an electron-impact ionization mass spectrometer. The concentrations of HNO3 and HBr in the presence of salts were monitored mass spectrometrically, and their decay rates were used to obtain uptake coefficients. The sizes of NaBr and NaNO3 granules were measured using an optical microscope, and their specific surface areas were estimated by a well-known relationship, Sg=6/d rho(t) where d is the average diameter of the granule and rho(t) is the true density of the NaBr or NaNO3 substrate. Our observations indicate that the uptake process comprises both physical adsorption and chemical reaction. The uptake coefficients for the forward and reverse processes, after accounting for internal surfaces by means of a mathematical model of surface reaction and pore diffusion, were found to be (2.8+/-0.5)x10(-3) and (1.2.+/-0.2)x10(-2) at 296 K, respectively. The error limits represent one standard deviation precision only. The implications for atmospheric chemistry in the marine boundary layer and Arctic troposphere are discussed. RP Leu, MT (reprint author), CALTECH,JET PROP LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 30 TC 12 Z9 13 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JAN 16 PY 1997 VL 101 IS 3 BP 278 EP 282 DI 10.1021/jp9626069 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WL084 UT WOS:A1997WL08400008 ER PT J AU Singh, HB Chen, Y Gregory, GL Sachse, GW Talbot, R Blake, DR Kondo, Y Bradshaw, JD Heikes, B Thornton, D AF Singh, HB Chen, Y Gregory, GL Sachse, GW Talbot, R Blake, DR Kondo, Y Bradshaw, JD Heikes, B Thornton, D TI Trace chemical measurements from the northern midlatitude lowermost stratosphere in early spring: Distributions, correlations, and fate SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NITROUS-OXIDE; AASE-II; TROPOSPHERE; OZONE; DC-8 AB In situ measurements of a large number of trace chemicals from the midlatitude (37-57 degrees N) lower stratosphere were performed with the NASA DC-8 aircraft during March 1994. Deepest penetrations into the stratosphere (550 ppb O-3, 279 ppb N2O, and 350 K potential temperature) corresponded to a region that has been defined as the ''lowermost stratosphere'' (LS) by Holton et al. [1995]. Analysis of data shows that the mixing ratios of long-lived tracer species (e. g. CH4, HNO3, NOy, CFCs) are linearly correlated with those of O-3 and N2O. A Delta NOy/Delta O-3 of 0.0054 ppb/ppb and Delta NOy/Delta N2O of -0.081 ppb/ppb Is in good agreement with other reported measurements from the DC-8. These slopes are however, somewhat steeper than those reported from the ER-2 airborne studies. We find that the reactive nitrogen budget in the LS is largely balanced with HNO3 accounting for 80% of NOy, and PAN and NOx together accounting for 5%. A number of oxygenated species (e. g. acetone, H2O2) were present and may provide an important in situ source of HOx in the LS. SO2 mixing ratios were found to increase in the stratosphere at a rate that was comparable to the decline in OCS levels. No evidence of particle formation could be observed. Ethane, propane, and acetylene mixing ratios declined rapidly in the LS with Cl atoms likely playing a key role in this process. A number of reactive hydrocarbons/halocarbons (e. g. C6H6, CH3I) were present at low but measurable concentrations. C1 NASA,LANGLEY RES CTR,HAMPTON,VA 23665. UNIV NEW HAMPSHIRE,DURHAM,NH 03824. UNIV CALIF IRVINE,IRVINE,CA 92717. NAGOYA UNIV,TOYOKAWA,JAPAN. GEORGIA INST TECHNOL,ATLANTA,GA 30332. UNIV RHODE ISL,NARRAGANSETT,RI 02882. DREXEL UNIV,PHILADELPHIA,PA 19104. RP Singh, HB (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. RI Kondo, Yutaka/D-1459-2012 NR 22 TC 47 Z9 47 U1 3 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 1997 VL 24 IS 2 BP 127 EP 130 DI 10.1029/96GL03770 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WD301 UT WOS:A1997WD30100005 ER PT J AU Wang, LP Koblinsky, C AF Wang, LP Koblinsky, C TI Can the Topex/Poseidon altimetry data be used to estimate air-sea heat flux in the North Atlantic? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN; TOPOGRAPHY; MODEL AB We propose a novel approach to directly invert large-scale anomalous annual net air-sea heat flux from the Topex/Poseidon altimetry data in the North Atlantic. The major advantage of this new approach over the conventional bulk formula approach is that it does not need those climate parameters used in the conventional bulk formula calculation in estimating the large-scale anomalous annual net air-sea heat flux. Comparison with expendable bathythermograph data demonstrates that it is a feasible approach. RP Wang, LP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UMD,JCESS,CODE 971,GREENBELT,MD 20771, USA. NR 16 TC 15 Z9 16 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 1997 VL 24 IS 2 BP 139 EP 142 DI 10.1029/96GL03695 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WD301 UT WOS:A1997WD30100008 ER PT J AU Mehta, VM Lau, KM AF Mehta, VM Lau, KM TI Influence of solar irradiance on the Indian monsoon-ENSO relationship at decadal-multidecadal time scales SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERANNUAL VARIABILITY; SOUTHERN OSCILLATION; SURFACE-TEMPERATURE; EL-NINO AB One hundred and nineteen years (1872-1990) of area-averaged rainfall over India, and sea surface temperature (SST) averaged over the equatorial central and eastern Pacific Ocean (the so-called Nino3 region) as an index of El Nino-Southern Oscillation (ENSO) are analyzed to study their covariability. The monsoon rainfall, SST, and their covariability undergo decadal-multidecadal variations without any dominant or distinct periodicities. The monsoon rainfall, SST, and their covariability are compared to solar irradiance at the top of the Earth's atmosphere for the same data period. At the 11 years time scale there is no consistent relationship between the monsoon rainfall and solar irradiance, and between the Nino3 SST and solar irradiance. The rainfall and irradiance appear to covary with nearly the same phase at multidecadal time scales. The Nino3 SST and irradiance appear to covary with nearly opposite phases at multidecadal time scales. The interannual covariability of the monsoon-ENSO system is also apparently modulated by this multidecadal variability. Based on these results, a hypothesis about the possible influence of solar irradiance in the ENSO-monsoon relationship at multidecadal time scales is described. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Mehta, VM (reprint author), UNIV MARYLAND,NASA,JOINT CTR EARTH SYST SCI,DEPT METEOROL,COLLEGE PK,MD 20742, USA. NR 18 TC 58 Z9 59 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 1997 VL 24 IS 2 BP 159 EP 162 DI 10.1029/96GL03778 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WD301 UT WOS:A1997WD30100013 ER PT J AU Sun, X Reid, JS Kolawa, E Nicolet, MA Ruiz, RP AF Sun, X Reid, JS Kolawa, E Nicolet, MA Ruiz, RP TI Reactively sputtered Ti-Si-N films .2. Diffusion barriers for Al and Cu metallizations on Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SILICON; TA AB Ti-Si-N films synthesized by reactively sputtering a TiSi2, a Ti5Si3, or a Ti3Si target in Ar/N-2 gas mixture were tested as diffusion barriers between planar (100) Si substrates and shallow n(+)p Si diodes, and Al or Cu overlayers. The stability of the Ti-Si-N barriers generally improves with increasing nitrogen concentration in the films, with the drawback of an increase in the film's resistivity. Ti34Si23N43 sputtered from the Ti5Si3 target is the most effective diffusion barrier among all the Ti-Si-N films studied. It works as an excellent barrier between Si and Cu. A film about 100 nm thick, with a resistivity of around 700 mu Omega cm, maintains the stability of Si n+p shallow junction diodes with a 400 nm Cu overlayer up to 850 degrees C for 30 min vacuum annealing. When it is used between Al and Si, the highest temperature of stability achievable with a 100-nm-thick film is 550 degrees C. A thermal treatment at 600 degrees C causes a severe intermixing of the layers. The microstructure, atomic density, and electrical resistivity of these films are described in an accompanying Part I. (C) 1997 American Institute of Physics. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP Sun, X (reprint author), CALTECH, PASADENA, CA 91125 USA. NR 23 TC 58 Z9 58 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JAN 15 PY 1997 VL 81 IS 2 BP 664 EP 671 DI 10.1063/1.364206 PG 8 WC Physics, Applied SC Physics GA WD716 UT WOS:A1997WD71600017 ER PT J AU Massom, RA Drinkwater, MR Haas, C AF Massom, RA Drinkwater, MR Haas, C TI Winter snow cover on sea ice in the Weddell Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SATELLITE PASSIVE MICROWAVE; THICKNESS DISTRIBUTION; SURFACE CHARACTERISTICS; MIXED LAYER; BACKSCATTER; ANTARCTICA; SIGNATURES; OCEAN; TEMPERATURES; ROUGHNESS AB Measurements of snow thickness, temperature, salinity, density, and stratigraphy acquired during the 1992 Winter Weddell Gyre Study are presented. Results indicate that the winter snow cover on sea ice in the Weddell Sea is extremely variable. Extreme fluctuations in Antarctic synoptic conditions (air temperature, precipitation; humidity, and wind speed) occur during the austral winter. They result in unique modifications and additions to the snow layer during the aging process and act to stabilize an otherwise easily wind-redistributed shallow snow cover and develop well-packed drift features. The latter occur even over relatively undeformed areas of sea ice and have a significant localized effect on the snow thickness distribution. Significant variability in snow grain size (mean 2.73 +/- 3.12 mm) and density (0.32 +/- 0.09 g cm(-3)) is observed as a result of cyclical switches between high- and low-temperature gradient metamorphism. Multiple icy layers indicate multiple thaw-freeze events. One such event occurred during a 3-day station, during which the air temperature rose by 22 degrees C in 12 hours (to approximately 0 degrees C). This paper also examines mechanisms for flooding of the snow-ice interface, including snow loading. Even where the latter is not a factor, the layer of snow immediately above the snow-ice interface is commonly damp and saline (>10 parts per thousand). Limitations in the data set are discussed, and comparisons are drawn with other experiments. C1 CALTECH,JET PROP LAB,NASA,PASADENA,CA 91109. ALFRED WEGENER INST POLAR & MARINE RES,D-27570 BREMERHAVEN,GERMANY. RP Massom, RA (reprint author), UNIV TASMANIA,ANTARCTIC COOPERAT RES CTR,GPO BOX 252-80,HOBART,TAS 7001,AUSTRALIA. RI Haas, Christian/L-5279-2016; OI Haas, Christian/0000-0002-7674-3500; Drinkwater, Mark/0000-0002-9250-3806 NR 62 TC 64 Z9 66 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JAN 15 PY 1997 VL 102 IS C1 BP 1101 EP 1117 DI 10.1029/96JC02992 PG 17 WC Oceanography SC Oceanography GA WC950 UT WOS:A1997WC95000014 ER PT J AU Eashoo, M Buckley, LJ StClair, AK AF Eashoo, M Buckley, LJ StClair, AK TI Fibers from a low dielectric constant fluorinated polyimide: Solution spinning and morphology control SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE coagulation; low dielectric constant; fiber; miscibility; morphology; solution spinning; polyimide; precipitation strength ID PERFORMANCE AB Control of the internal morphology of wet-spun fibers from a fluorinated polyimide has been achieved by varying the rate of polymer coagulation through adjustments in nonsolvent/ solvent miscibility and precipitation strength of the coagulation bath. Filament internal morphologies ranged from very porous or sponge-like to fully solid. Intermediate structures included fibers containing a spongy core with a nonporous skin, sponge-like fibers containing large voids, and a relatively solid material containing randomly spaced small voids. The cross-sectional shape of the fiber is dependent upon the coagulation process as well as the volume contraction of the initial extrudate. Drawn fibers (3X) retained the original as-spun cross-sectional shape and also lost porosity. Mechanical properties of poly(6FDA-4BDAF) fibers have an inverse relationship to filament porosity. Maximum modulus and break strength for drawn fibers is approximately 6 GPa and 200 MPa, respectively. As-spun mechanical properties were dependent upon the processing conditions and have moduli between 0.4-3.0 Cpa and break strengths of 10-160 MPa. A dielectric constant of 2.50 for nonporous films was measured over a frequency range between 1.0 MHz to 1.8 GHz, showing little dispersion. (C) 1997 John Wiley & Sons, Inc. C1 USN,RES LAB,DIV CHEM,WASHINGTON,DC 20375. NASA,LANGLEY RES CTR,DIV MAT,HAMPTON,VA 23681. NR 20 TC 9 Z9 10 U1 2 U2 11 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD JAN 15 PY 1997 VL 35 IS 1 BP 173 EP 185 DI 10.1002/(SICI)1099-0488(19970115)35:1<173::AID-POLB15>3.0.CO;2-A PG 13 WC Polymer Science SC Polymer Science GA VZ964 UT WOS:A1997VZ96400015 ER PT J AU Davis, A Marshak, A Cahalan, R Wiscombe, W AF Davis, A Marshak, A Cahalan, R Wiscombe, W TI The landsat scale break in stratocumulus as a three-dimensional radiative transfer effect: Implications for cloud remote sensing SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERIC TRANSFER; MEDIA; SCATTERING; FIELDS; ALBEDO; MODEL; RAIN AB Several studies have uncovered a break in the scaling properties of Landsat cloud scenes at nonabsorbing wavelengths. For scales greater than 200-400 m, the wavenumber spectrum is approximately power law in k(-5/3), but from there down to the smallest observable scales (50-100 m) follows another k(-beta) law with beta >3. This implies very smooth radiance fields. The authors reexamine the empirical evidence for this scale break and explain it using fractal cloud models, Monte Carlo simulations, and a Green function approach to multiple scattering theory. In particular, the authors define the ''radiative smoothing scale'' and relate it to the characteristic scale of horizontal photon transport. The scale break was originally thought to occur at a scale commensurate with either the geometrical thickness Delta(z) of the cloud, or with the ''transport'' mean free path l(t)=[(1-g)sigma](-1), which incorporates the effect of forward scattering (sigma is extinction and g the asymmetry factor of the phase Function). The smoothing scale is found to be approximately root l(t) Delta(z) at cloud top; this is the prediction of diffusion theory which applies when (1-g)tau=Delta(z)/l greater than or similar to 1 (tau is optical thickness). Since the scale break is a tangizble effect of net horizontal radiative fluxes excited by the fluctuations of tau, the smoothing scale sets an absolute lower bound on the range where one can neglect these fluxes and use plane-parallel theory locally, even for stratiform clouds. In particular, this constrains the retrieval of cloud properties from remotely sensed data. Finally, the characterization of horizontal photon transport suggests a new lidar technique for joint measurements of optical and geometrical thicknesses at about 0.5-km resolution. RP Davis, A (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CLIMATE & RADIAT BRANCH, CODE 913, GREENBELT, MD 20771 USA. RI Cahalan, Robert/E-3462-2012; Wiscombe, Warren/D-4665-2012; Marshak, Alexander/D-5671-2012 OI Cahalan, Robert/0000-0001-9724-1270; Wiscombe, Warren/0000-0001-6844-9849; NR 53 TC 146 Z9 147 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JAN 15 PY 1997 VL 54 IS 2 BP 241 EP 260 DI 10.1175/1520-0469(1997)054<0241:TLSBIS>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ819 UT WOS:A1997WJ81900001 ER PT J AU Chen, BX Xu, JH Uher, C Morelli, DT Meisner, GP Fleurial, JP Caillat, T Borshchevsky, A AF Chen, BX Xu, JH Uher, C Morelli, DT Meisner, GP Fleurial, JP Caillat, T Borshchevsky, A TI Low-temperature transport properties of the filled skutterudites CeFe4-xCoxSb12 SO PHYSICAL REVIEW B LA English DT Article ID COSB3 AB Thermal conductivity, thermoelectric power, electrical resistivity, Hall coefficient, and magnetic susceptibility of the filled skutterudites CeFe4-xCoxSb12, with x = 0, 0.5, 1.0, 1.5, and 2.0, have been studied from 2 to 300 K. We find that the substitution of Co at Fe sites has a dramatic effect on all transport properties. While the resistivity of CeFe4Sb12 has a metallic character, substitution of Co leads to a progressively stronger activated behavior and a decrease in hole concentration. The thermopower increases with increasing Co, while the thermal conductivity is depressed, notably at low temperatures. Susceptibility data suggest the presence of large effective moments. At high temperatures Ce is nearly trivalent, but valence fluctuations prevail at low temperatures. Strong hybridization of the Ce 4f states with the Fe 3d and pnicogen p states appears to be important in understanding the physical properties of these compounds. C1 GM CORP,CTR RES & DEV,PHYS & PHYS CHEM DEPT,WARREN,MI 48090. CALTECH,JET PROP LAB,PASADENA,CA 91109. RP Chen, BX (reprint author), UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109, USA. NR 16 TC 190 Z9 203 U1 3 U2 29 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1997 VL 55 IS 3 BP 1476 EP 1480 DI 10.1103/PhysRevB.55.1476 PG 5 WC Physics, Condensed Matter SC Physics GA WF303 UT WOS:A1997WF30300041 ER PT J AU Heckler, AF AF Heckler, AF TI Formation of a Hawking-radiation photosphere around microscopic black holes SO PHYSICAL REVIEW D LA English DT Article ID GAMMA-RAYS; TEMPERATURE AB We show that once a black hole surpasses some critical temperature T-crit, the emitted Hawking radiation interacts with itself and forms a nearly thermal photosphere. Using QED, we show that the dominant interactions are bremsstrahlung and electron-photon pair production, and we estimate T(crit)similar to m(e)/alpha(5/2), which when calculated more precisely is found to be T(crit)approximate to 45 GeV. The formation of the photosphere is purely a particle physics effect, and not a general relativistic effect, since the photosphere forms roughly alpha(-4) Schwarzschild radii away from the black hole. The temperature T of the photosphere decreases with distance from the black hole, and the outer surface is determined by the constraint T similar to m(e) (for the QED case), since this is the point at which electrons and positrons annihilate, and the remaining photons free stream to infinity. Observational consequences are discussed, and it is found that, although the QED photosphere will not affect the Page-Hawking limits on primordial black holes, which is most important for 100 MeV black holes, the inclusion of QCD interactions may significantly effect this limit, since for QCD we estimate T(crit)similar to Lambda(QCD). The photosphere greatly reduces the possibility of observing individual black holes with temperatures greater than T-crit, since the high energy particles emitted from the black hole are processed through the photosphere to a lower energy, where the gamma-ray background is much higher. The temperature of the plasma in the photosphere can be extremely high, and this offers interesting possibilities for processes such as symmetry restoration. RP Heckler, AF (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. RI Heckler, Andrew/A-7291-2010 OI Heckler, Andrew/0000-0001-5494-7855 NR 21 TC 44 Z9 44 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1997 VL 55 IS 2 BP 480 EP 488 DI 10.1103/PhysRevD.55.480 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WF296 UT WOS:A1997WF29600008 ER PT J AU Semikoz, DV Tkachev, II AF Semikoz, DV Tkachev, II TI Condensation of bosons in the kinetic regime SO PHYSICAL REVIEW D LA English DT Article ID BOSE-EINSTEIN CONDENSATION; POLARIZED ATOMIC-HYDROGEN; POPULATION-DYNAMICS; SCALAR FIELDS; STARS; GAS; AXION; SCATTERING; SATURATION; EVOLUTION AB We study the kinetic regime of the Bose condensation of scalar particles. The Boltzmann equation is solved numerically. We consider two kinetic stages. At the first stage the condensate is absent but there is a nonzero inflow of particles towards p=0 and the distribution function at p=0 grows from finite values to infinity in a finite time. We observe a profound similarity between Bose condensation and Kolmogorov turbulence. At the second stage there are two components, the condensate and particles, reaching their equilibrium values. We show that the evolution in both stages proceeds in a self-similar way and find the time needed for condensation. We do not consider a phase transition from the first stage to the second. Condensation of self-interacting bosons is compared to the condensation driven by interaction with a cold gas of fermions; the latter turns out to be self-similar too. Exploiting the self-similarity we obtain a number of analytical results in all cases. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Semikoz, DV (reprint author), RUSSIAN ACAD SCI,INST NUCL RES,60TH OCTOBER ANNIVERSARY PROSPECT 7,MOSCOW 117312,RUSSIA. NR 58 TC 83 Z9 84 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1997 VL 55 IS 2 BP 489 EP 502 DI 10.1103/PhysRevD.55.489 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WF296 UT WOS:A1997WF29600009 ER PT J AU Abney, M AF Abney, M TI Fluctuations and bubble dynamics in first-order phase transitions SO PHYSICAL REVIEW D LA English DT Article ID SUBCRITICAL BUBBLES; FALSE VACUUM; FINITE-TEMPERATURE; BARYON ASYMMETRY; WALL VELOCITY; ELECTROWEAK; BARYOGENESIS; INSTABILITY; DIMENSIONS; EQUILIBRIUM AB We numerically examine the effect of thermal fluctuations on a first-order phase transition in (2 + 1) dimensions. By focusing on the expansion of a single bubble we are able to calculate changes in the bubble wall's velocity as well as changes in its structure relative to the standard case where the bubble expands into a homogeneous background. Not only does the wall move faster, but the transition from the symmetric to the asymmetric phase is no longer smooth, even for a fairly strong transition. We discuss how these results affect the standard picture of electroweak baryogenesis. C1 FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. RP Abney, M (reprint author), UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637, USA. NR 57 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1997 VL 55 IS 2 BP 582 EP 594 DI 10.1103/PhysRevD.55.582 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WF296 UT WOS:A1997WF29600018 ER PT J AU Turner, MS AF Turner, MS TI Detectability of inflation-produced gravitational waves SO PHYSICAL REVIEW D LA English DT Article ID TENSOR PERTURBATIONS; DENSITY PERTURBATIONS; BACKGROUND-RADIATION; UNIVERSE; ANISOTROPY; COBE; COSMOLOGY; MODELS; SCALE; FLUCTUATIONS AB Detection of the gravitational waves excited during inflation as quantum-mechanical fluctuations is a key test of inflation and crucial to learning about the specifics of the inflationary model. We discuss the potential of cosmic background radiation anisotropy and polarization and of laser interferometers such as LIGO, VIRGO, and LISA to detect these gravity waves. C1 FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60615 USA. RP UNIV CHICAGO, ENRICO FERMI INST, 5640 S ELLIS AVE, CHICAGO, IL 60637 USA. NR 43 TC 70 Z9 70 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1997 VL 55 IS 2 BP R435 EP R439 DI 10.1103/PhysRevD.55.R435 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WF296 UT WOS:A1997WF29600001 ER PT J AU Nandra, K Mushotzky, RF Yaqoob, T George, IM Turner, TJ AF Nandra, K Mushotzky, RF Yaqoob, T George, IM Turner, TJ TI Variability of the iron K emission line in the Seyfert 1 galaxy NGC 3516 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; galaxies, active; galaxies, individual, NGC 3516; galaxies, nuclei; galaxies, Seyfert; X-rays, galaxies ID GINGA; DISK AB We present strong evidence for variability of the flux of the iron K alpha emission line in the Seyfert 1 galaxy NGC 3516. Two ASCA observations, separated by similar to 1 yr, show a marked decrease in continuum flux by similar to 60 per cent. The flux in the broad iron K alpha line decreased by the same factor in this time period, with no evidence for changes in the line profile. The line variability is significant at > 99 per cent confidence, and rules out models in which the line is produced in a molecular torus located at > 1 pc from the nucleus. An accretion disc is considerably more likely. RP Nandra, K (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,CODE 660,GREENBELT,MD 20771, USA. NR 17 TC 24 Z9 24 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 11 PY 1997 VL 284 IS 2 BP L7 EP L10 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC928 UT WOS:A1997WC92800001 ER PT J AU Marani, GF Nemiroff, RJ Norris, JP Bonnell, JT AF Marani, GF Nemiroff, RJ Norris, JP Bonnell, JT TI On suggestive correlations between gamma-ray bursts and clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, clusters, general; gamma rays, bursts ID CATALOG AB Recent claims of angular correlations between gamma-ray bursts (GRBs) and clusters of galaxies are evaluated in light of existing but previously uncorrelated GRB positional data. Additional GRB data sets we use include subsamples of soft BATSE 3B bursts, bursts located by the Interplanetary Network (IPN), and GRBs localized by COMPTEL. We confirm a previously reported excess by Rood & Struble (1996) of the 185 rich, nearby clusters of galaxies (Abell, Corwin, & Olowin 1989; ACO clusters) in the 1 sigma error circles of 74 BATSE 3B positions but find a typical correlation strength of only 2.5 sigma for typical subsamples. However, none of the 185 ACO clusters occur in the 1 sigma error boxes of 40 IPN GRBs or 18 COMPTEL GRBs. When all ACO clusters are correlated with BATSE 3B GRBs, however, we find an increasingly strong correlation for GRBs with decreasingly small error boxes, reaching above the 3.5 sigma level. We also find a slight excess of soft BATSE GRBs near the positions of 185 rich, nearby ACO clusters, but the significance of the correlation averages only 2.5 sigma for subsamples delineated by softness. We caution that the statistical significance of all these correlations is marginal and so conclude that the excess is at best only suggestive of a physical association. Statistical fluke is still a strong possibility. BATSE could confirm or refute such correlations in a 10 year lifetime. C1 MICHIGAN TECHNOL UNIV,DEPT PHYS,HOUGHTON,MI 49931. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Marani, GF (reprint author), GEORGE MASON UNIV,CTR EARTH & SPACE RES,FAIRFAX,VA 22030, USA. NR 22 TC 10 Z9 10 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP 576 EP 579 DI 10.1086/303485 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC498 UT WOS:A1997WC49800004 ER PT J AU Michalitsianos, AG Dolan, JF Kazanas, D Bruhweiler, FC Boyd, PT Hill, RJ Nelson, MJ Percival, JW vanCitters, GW AF Michalitsianos, AG Dolan, JF Kazanas, D Bruhweiler, FC Boyd, PT Hill, RJ Nelson, MJ Percival, JW vanCitters, GW TI L gamma alpha absorption-line systems in the gravitational lens Q0957+561 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gravitational lensing; quasars, absorption lines; quasars, emission lines; quasars, individual (Q0957+561); ultraviolet, galaxies ID LYMAN-ALPHA; GALAXY; ULTRAVIOLET; SIZE AB Far-ultraviolet spectra of the gravitational lens components Q0957+561A and B were obtained with the Hubble Space Telescope Faint Object Spectrograph (HST FOS). Two previously known absorption-line systems were detected at redshifts z(damped) = 1.3911 and z(Ly alpha) = 1.1249. Their prominent absorption features are superposed on intense QSO continuum emission between lambda lambda 900-1400 in the quasar rest frame. Strong O VI lambda 1033, Ly alpha lambda 1216, and N V lambda 1240 line emission found at the QSO redshift (Z(QSO) = 1.41) accompany the absorption-line systems. Ly alpha through Ly epsilon associated with the damped absorption system were found in both lensed components, together with other ionic species of N I, N III, C II, C III, Si II, Si III, and O I. We tentatively identify O VI lambda lambda 1033, 1037 absorption at the damped Ly alpha redshift, which, if confirmed, would be the highest ionization species yet detected in such systems. The equivalent widths of the Lyman series in Q0957+561A are measurably greater compared with absorption in 0957+561B, consistent with the narrower and shallower depth of the Lyman series line profiles in image B. The differences of the damped Lyman series absorption in the lensed components are the only significant spectral characteristic that distinguishes the far-ultraviolet spectra of 0957+561A and B. These results indicate that the damped Ly alpha absorber is inhomogeneous over scale lengths of similar to 200 pc, which corresponds to the beam separation at the damped Ly alpha redshift. However, the equivalent widths of neutral and ionized metals in lens components A and B are correlated, which suggests these spectral features arise in an extended region. The metal line-absorption strength is consistent with lower column densities compared with the hydrogen line-forming region. Thus, the small coherence length scale indicated by the difference in hydrogen line absorption between the lensed components suggests the geometric ray paths intercept different regions of a galactic disk that is viewed pole-on, while the metal absorption occurs in the halo. C1 NASA, GODDARD SPACE FLIGHT CTR, HIGH ENERGY ASTROPHYS LAB, GREENBELT, MD 20771 USA. CATHOLIC UNIV AMER, DEPT PHYS, WASHINGTON, DC 20064 USA. NASA, GODDARD SPACE FLIGHT CTR, UNIV SPACE RES ASSOC, GREENBELT, MD 20771 USA. NASA, GODDARD SPACE FLIGHT CTR, HUGHES STX CORP, GREENBELT, MD 20771 USA. UNIV WISCONSIN, SPACE ASTRON LAB, MADISON, WI 53706 USA. NATL SCI FDN, DIV ASTRON SCI, ARLINGTON, VA 22230 USA. RP Michalitsianos, AG (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 680, GREENBELT, MD 20771 USA. RI Boyd, Patricia/D-3274-2012 NR 31 TC 16 Z9 16 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP 598 EP 605 DI 10.1086/303491 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC498 UT WOS:A1997WC49800006 ER PT J AU Sambruna, RM Urry, CM Maraschi, L Ghisellini, G Mukherjee, R Pesce, JE Wagner, SJ Wehrle, AE Hartman, RC Lin, YC vonMontigny, C AF Sambruna, RM Urry, CM Maraschi, L Ghisellini, G Mukherjee, R Pesce, JE Wagner, SJ Wehrle, AE Hartman, RC Lin, YC vonMontigny, C TI The high-energy continuum emission of the gamma-ray blazar PKS 0528+134 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, active; galaxies, individual (PKS 0528 + 134); gamma rays, observations; radiation mechanisms, nonthermal; X-rays, galaxies ID EXTRAGALACTIC RADIO-SOURCES; ACTIVE GALACTIC NUCLEI; HIGH-REDSHIFT QUASARS; SPECTRA; ABSORPTION; ASCA; POLARIZATIONS; EXTINCTION; RADIATION; GALAXIES AB We present Advanced Satellite for Cosmology and Astrophysics (ASCA) observations of the gamma-ray blazar PKS 0528 + 134, obtained at two separate epochs in 1994 August and 1995 March. These data represent the first measurement of the X-ray continuum emission of this source in the medium-hard X-ray band. Both ASCA spectra are consistent with a single power law with photon index Gamma similar to 1.7-1.8 and column density N-H similar to 5 x 10(21) cm(-2), higher than Galactic. The X-ray flux increased by a factor of 4 in similar to 7 months without appreciable change of the spectral shape. During the lower state of 1994 August, PKS 0528 + 134 was observed simultaneously in the optical, X-rays,. and at gamma-ray energies with EGRET. The gamma-ray intensity is the faintest detected thus far in the source, with a steep spectrum (Gamma similar to 2.7). The extrapolation of the X-ray continuum to the gamma-ray range requires a sharp spectral break at similar to 10(22) Hz. We discuss the radio through gamma-ray spectral energy distribution of PKS 0528 + 134, comparing the low state of 1994 August with the flare state of 1993 March. We show that in PKS 0528+134, a nonnegligible contribution from the external radiation held is present and that, although synchrotron self-Compton scenarios cannot be ruled out, inverse Compton upscattering of thermal seed photons may be the dominant cooling process for the production of the high-energy continuum in this blazar. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. OSSERV ASTRON BRERA,I-20128 MILAN,ITALY. LANDESSTERNWARTE KONIGSTUHL,D-69117 HEIDELBERG,GERMANY. CALTECH,CTR INFRARED PROC & ANAL,PASADENA,CA 91125. STANFORD UNIV,HIGH ENERGY PHYS LAB,STANFORD,CA 94305. RP Sambruna, RM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. RI Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 48 TC 40 Z9 41 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP 639 EP 649 DI 10.1086/303493 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC498 UT WOS:A1997WC49800012 ER PT J AU Weaver, KA Yaqoob, T Mushotzky, RF Nousek, J Hayashi, I Koyama, K AF Weaver, KA Yaqoob, T Mushotzky, RF Nousek, J Hayashi, I Koyama, K TI Iron K alpha evidence for two X-ray reprocessors in MCG-5-23-16 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (MCG -5-23-16); galaxies, kinematics and dynamics; galaxies, nuclei; galaxies, Seyfert; line, profiles; X-rays, galaxies ID SEYFERT-1 GALAXIES; ASCA OBSERVATION; LINE EMISSION; BLACK-HOLE; DISK AB We report a remarkable Fe K alpha fluorescence line profile in the Seyfert 1.9 galaxy MCG -5-23-16. The line is complex, consisting of a narrow core located at the galaxy's systemic velocity and wings to the red and blue sides of the core. This represents only the second detection with ASCA of an Fe K alpha line profile with significant broadening blueward of 6.4 keV, consistent with Doppler boosting. The line core has an EW of similar to 60 eV and the wings have a combined EW of similar to 200 eV. The entire profile cannot be easily modeled with an emission line predicted from standard accretion disk theories. Instead, the line is marginally triple-peaked and is best described with three Gaussians having rest energies of 5.37(-0.19)(+0.23) keV (FWHM = 30,200 km s(-1)), 6.37 +/- 0.04 keV (FWHM < 6,600 km s(-1)), and 6.58(-0.38)(+0.35) keV (FWHM = 75,300 km s(-1)). The line can also be modeled with a narrow Gaussian at similar to 6.4 keV and an emission line from an accretion disk viewed at an inclination angle of similar to 30 degrees to 65 degrees, depending on the ionization state of the gas. Within the context of the unified model, the most likely physical description of the complex profile is a superposition of an emission line from an accretion disk and a line that arises far from the disk in either the obscuring torus or the broad line region. This represents the first strong evidence for emission from two distinct X-ray reprocessors within a single Seyfert 1-type galaxy. C1 PENN STATE UNIV,DEPT ASTRON & ASTROPHYS,DAVEY LAB 525,UNIVERSITY PK,PA 16802. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. KYOTO UNIV,FAC SCI,DEPT PHYS,SAKYO KU,KYOTO 60601,JAPAN. RP Weaver, KA (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BLOOMBERG CTR,BALTIMORE,MD 21218, USA. NR 34 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 JAN 10 PY 1997 VL 474 IS 2 BP 675 EP 685 DI 10.1086/303488 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC498 UT WOS:A1997WC49800015 ER PT J AU Sloan, GC Bregman, JD Geballe, TR Allamandola, LJ Woodward, CE AF Sloan, GC Bregman, JD Geballe, TR Allamandola, LJ Woodward, CE TI Variations in the 3 micron spectrum across the Orion Bar: Polycyclic aromatic hydrocarbons and related molecules SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared, ISM, lines and bands; ISM, individual (Orion Bar); ISM, molecules ID INFRARED-EMISSION BANDS; AMORPHOUS-CARBON; IR EMISSION; FEATURES; NEBULAE; IDENTIFICATION; EVOLUTION; DUST AB Long-slit spectra across the Orion Bar reveal significant differences in the spatial behavior of the components of the 3 mu m polycyclic aromatic hydrocarbon (PAH) spectrum. The strong PAH band at 3.29 mu m generally decreases exponentially with distance from the ionization front into the molecular cloud (scale height similar to 12 ''), although excesses appear similar to 10 '' and similar to 20 '' behind the ionization front, close to layers of H-2 and CO emission, respectively. The 3.40 mu m PAH feature separates into two components with very different spatial distributions. The main component (at 3.395 mu m), along with the 3.51 mu m band and the PAH plateau (3.3-3.6 mu m), shows excess emission similar to 10 '' and similar to 20 '' behind the ionization front, stronger than the excesses in the 3.29 mu m band. The extra component of the 3.40 mu m band, which peaks at similar to 3.405 mu m, has a spatial distribution very similar to the H-2 emission. Aromatic C-H stretches in PAHs most likely produce the 3.29 mu m feature. Aliphatic C-H stretches in either attached methyl side-groups or superhydrogenated PAHs, or perhaps both, could produce the complicated spectral and spatial structure at 3.40 mu m. C1 JOINT ASTRON CTR,HILO,HI 96720. UNIV WYOMING,DEPT PHYS & ASTRON,LARAMIE,WY 82071. RP Sloan, GC (reprint author), NASA,AMES RES CTR,MS 245-6,MOFFETT FIELD,CA 94035, USA. NR 33 TC 59 Z9 59 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP 735 EP 740 DI 10.1086/303484 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC498 UT WOS:A1997WC49800022 PM 11539404 ER PT J AU Greenhill, LJ Ellingsen, SP Norris, RP Gough, RG Sinclair, MW Moran, JM Mushotzky, R AF Greenhill, LJ Ellingsen, SP Norris, RP Gough, RG Sinclair, MW Moran, JM Mushotzky, R TI Extremely rapid variations of water maser emission from the Circinus galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, individual (Circinus); galaxies, kinematics and dynamics; galaxies, nuclei masers ID ACTIVE GALACTIC NUCLEI; VAPOR MASER; H2O MASERS; SPECTRUM; REGION; VARIABILITY; VELOCITIES; OH AB The water maser lines in the Seyfert nucleus of the Circinus galaxy vary on timescales as short as a few minutes. The amplitude of one line more than doubled in approximate to 10 minutes, reaching approximate to 37 Jy, which corresponded to an increase of approximate to 6 L., assuming isotropic emission, in a single maser feature on a size scale of about 1 AU, based on light-travel time. Other lines vary by up to about 30% on similar timescales. The variability is at least 2 orders of magnitude more rapid than any observed for other Galactic or extragalactic water masers. The intensity changes cannot be attributed easily to a mechanism of intrinsic fluctuations. The variability may be the result of strong interstellar diffractive scintillation along the line of sight within our Galaxy. This would be the first example of diffractive scintillation for any source at 22 GHz and for any source other than a pulsar. However, only the very shortest timescales for interstellar scintillation, obtained from pulsar observations and scaled to 22 GHz, correspond to the observed maser variability. Alternatively, the intensity changes may be a reaction to fluctuations in compact background or radiative pump sources and thereby may be related to variability of the central engine. The maser spectral features symmetrically bracket the systemic velocity of the galaxy, with components red- and blueshifted by about +/-(100-200) km s(-1). The spectrum of the Circinus maser is similar in some respects to that of the maser in NGC 4258, which probably traces a molecular disk rotating around a supermassive object. VLBI observations could reveal whether the maser source in the heart of the Circinus galaxy is part of a similar dynamical system. C1 UNIV TASMANIA,HOBART,TAS 7001,AUSTRALIA. CSIRO,AUSTRALIA TELESCOPE NATL FACIL,EPPING,NSW 2121,AUSTRALIA. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. RP Greenhill, LJ (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. RI Ellingsen, Simon/J-7754-2014; Norris, Ray/A-1316-2008; OI Ellingsen, Simon/0000-0002-1363-5457; Norris, Ray/0000-0002-4597-1906; Moran, James/0000-0002-3882-4414 NR 36 TC 51 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP L103 EP L106 DI 10.1086/310434 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC500 UT WOS:A1997WC50000007 ER PT J AU Ong, KK Musielak, ZE Rosner, R Suess, ST Sulkanen, ME AF Ong, KK Musielak, ZE Rosner, R Suess, ST Sulkanen, ME TI Self-consistent and time-dependent solar wind models SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; solar wind; waves ID ALFVEN WAVES; STELLAR ATMOSPHERES; MAGNETIC-FIELD; REFLECTION; ACCELERATION; PROPAGATION; LINES AB We describe the first results from a self-consistent study of Alfven waves for the time-dependent, single-fluid magnetohydrodynamic (MHD) solar wind equations, using a modified version of the ZEUS MHD code. The wind models we examine are radially symmetrical and magnetized; the initial outflow is described by the standard Parker wind solution. Our study focuses on the effects of Alfven waves on the outflow and is based on solving the full set of the ideal nonlinear MHD equations. In contrast to previous studies, no assumptions regarding wave linearity, wave damping, and wave-flow interaction are made; thus, the models naturally account for the back-reaction of the wind on the waves, as well as for the nonlinear interaction between different types of MHD waves. Our results clearly demonstrate when momentum deposition by Alfven waves in the solar wind can be sufficient to explain the origin of fast streams in solar coronal holes; we discuss the range of wave amplitudes required to obtained such fast stream solutions. C1 UNIV CHICAGO, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB, HUNTSVILLE, AL 35812 USA. RP Ong, KK (reprint author), UNIV ALABAMA, CTR SPACE PLASMA AERONOM & ASTROPHYS RES, HUNTSVILLE, AL 35899 USA. NR 31 TC 7 Z9 7 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP L143 EP L145 DI 10.1086/310435 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC500 UT WOS:A1997WC50000017 ER PT J AU Rubin, RH Dufour, RJ Ferland, GJ Martin, PG ODell, CR Baldwin, JA Hester, JJ Walter, DK Wen, Z AF Rubin, RH Dufour, RJ Ferland, GJ Martin, PG ODell, CR Baldwin, JA Hester, JJ Walter, DK Wen, Z TI [Fe IV] in the Orion Nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE H II regions; ISM, abundances; ISM, atoms; ISM, individual (Orion Nebula) ID ABUNDANCES; SILICON; IUE; CARBON; LINES; MODEL; IRON AB Using the Goddard High-Resolution Spectrograph on the Hubble Space Telescope, we measured the flux of [Fe IV] (3d(5 4)P(5/2) --> 3d(5 ?6S?(5/2)) lambda(rac) = 2836.56 Angstrom in the Orion Nebula, the first detection of an [Fe IV] line in an H II region. A useful upper limit is set on the sum of fluxes of [Fe IV] (3d(5) D-4(5/2,3/2) --> 3d(5) S-6(5/2)) lambda(rac) = 2568.4, 2568.2 Angstrom. By comparing these observations with predicted fluxes from simply ''retrofitting'' our two previous photoionization models, we are able to derive (or set an upper limit on) the Fe/H abundance ratio: 70, 200 times lower than solar from the 2837 Angstrom line, and greater than or equal to 38, greater than or equal to 120 times lower than solar from the 2568 Angstrom line limit. If collisional excitation from the ground state were indeed the dominant mechanism for populating the respective upper levels of these lines, then the inferred Fe/H from the 2837 Angstrom line and Limit from the 2568 Angstrom line would be similar to 3.0 and similar to 3.4 times larger than above. All these ratios are much lower than several recent determinations of gas-phase Fe/H similar to 3 X 10(-6) in Orion, which themselves are a factor similar to 10 depleted relative to solar. Because the inferred Fe/H should be at least as high in the Fe+3 zone as in the Fe+ and Fe+2 zones, a reexamination of the Fe+3 atomic data and improved modeling would be valuable. C1 RICE UNIV, DEPT SPACE PHYS & ASTRON, HOUSTON, TX 77251 USA. UNIV KENTUCKY, DEPT PHYS & ASTRON, LEXINGTON, KY 40503 USA. UNIV TORONTO, CANADIAN INST THEORET ASTROPHYS, TORONTO, ON M5S 3H8, CANADA. CERRO TOLOLO INTERAMER OBSERV, LA SERENA, CHILE. ARIZONA STATE UNIV, DEPT PHYS & ASTRON, TEMPE, AZ 85287 USA. S CAROLINA STATE UNIV, ORANGEBURG, SC 29117 USA. RP Rubin, RH (reprint author), NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. OI Ferland, Gary/0000-0003-4503-6333 NR 31 TC 34 Z9 34 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP L131 EP + DI 10.1086/310437 PN 2 PG 0 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC500 UT WOS:A1997WC50000014 ER PT J AU Woo, R Habbal, SR AF Woo, R Habbal, SR TI Finest filamentary structures of the corona in the slow and fast solar wind SO ASTROPHYSICAL JOURNAL LA English DT Article DE interplanetary medium; solar wind; Sun, corona ID ELECTRON-DENSITY FLUCTUATIONS; DOPPLER SCINTILLATION; INTERPLANETARY DISTURBANCES; 0.3 AU; SPECTRUM; TURBULENCE; STREAMERS; SUN; SPEED; 1-AU AB Recent progress in our understanding of electron density fluctuations observed by radio occultation measurements has demonstrated that a break in the vicinity of 1 Hz in the temporal frequency spectrum of the density fluctuations provides a measure of the size of the finest filamentary structures in the solar corona. Breaks in frequency have been inferred from the density spectra deduced by Coles et al. from 1979-1980 Voyager phase scintillation and spectral broadening measurements. These results show that the finest filamentary structures are found in the extensions or stalks of coronal streamers-the likely sources of the slow solar wind-and are over a factor of 3 smaller than those in the fast wind emanating from coronal holes. The inferred sizes of the finest filamentary structures are approximately 6 km in the slow wind at 8 R. and 22 km in the fast wind at 9.1 R.. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. RP Woo, R (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 238-725,PASADENA,CA 91109, USA. NR 33 TC 48 Z9 48 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 1997 VL 474 IS 2 BP L139 EP L142 DI 10.1086/310432 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC500 UT WOS:A1997WC50000016 ER PT J AU Bliven, LF Sobieski, PW Craeye, C AF Bliven, LF Sobieski, PW Craeye, C TI Rain generated ring-waves: Measurements and modelling for remote sensing SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID DEVELOPED SEA MODELS; WATER-SURFACE; SCATTEROMETRY; SCATTERING; WIND AB We present an analysis of ring-wave and scatterometer data from a water surface that was agitated by simulated rain. Water droplets of 2.8 mm diameter impacted the water surface at almost terminal velocity, and the rain rates cover a wide range of conditions (5 to 200 mm hr(-1)). Both the ring-wave energy and backscattered power from the GHz scatterometer increase as R increases, but the growth rates slacken at higher rain intensities. Ring-wave frequency spectra and wavenumber spectra are well represented by log-Gaussian spectral models. The results can be used to guide development of microwave scattering models. C1 UNIV CATHOLIQUE LOUVAIN,LAB TELECOMMUN & TELEDECT,B-1348 LOUVAIN,BELGIUM. RP Bliven, LF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,WALLOPS ISL,VA 23337, USA. RI bliven, francis/E-1450-2012 NR 16 TC 55 Z9 55 U1 1 U2 5 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 10 PY 1997 VL 18 IS 1 BP 221 EP 228 DI 10.1080/014311697219385 PG 8 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA WC493 UT WOS:A1997WC49300016 ER PT J AU Raman, G AF Raman, G TI Screech tones from rectangular jets with spanwise oblique shock-cell structures SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SUPERSONIC JETS; INSTABILITY; MODEL; NOISE AB Understanding screech is especially important for the design of advanced aircraft because screech can cause sonic fatigue failure of aircraft structures. Although the connection between shock-cell spacing and screech frequency is well understood, the relation between non-uniformities in the shock-cell structures and the resulting amplitude, mode, and steadiness of screech have remained unexplored. This paper addresses the above issues by intentionally producing spanwise (larger nozzle dimension) variations in the shock-cell structures and studying the resulting spanwise screech mode. The spanwise-oblique shock-cell structures were produced using imperfectly expanded convergent-divergent rectangular nozzles (aspect ratio = 5) with non-uniform exit geometries. Three geometries were studied: (a) a nozzle with a spanwise uniform edge, (b) a nozzle with a spanwise oblique (single-bevelled) edge, and (c) a nozzle that had two spanwise oblique (double-bevelled) cuts to form an arrowhead-shaped nozzle. For all nozzles considered, the screech mode was antisymmetric in the transverse (smaller nozzle dimension) direction allowing focus on changes in the spanwise direction. Three types of spanwise modes were observed: symmetric (I), antisymmetric (II), and oblique (III), The following significant results emerged: (i) for all cases the screech mode corresponds with the spanwise shock-cell structure, (ii) when multiple screech modes are present, the technique presented here makes it possible to distinguish between coexisting and mutually exclusive modes, (iii) the strength of shocks 3 and 4 influences the screech source amplitude and determines whether screech is unsteady. The results presented here offer hope for a better understanding of screech and for tailoring shock-containing jets to minimize fatigue failure of aircraft components. RP Raman, G (reprint author), NASA,LEWIS RES CTR GRP,NYMA INC,EXPT FLUID DYNAM SECT,BROOKPARK,OH 44142, USA. NR 51 TC 25 Z9 25 U1 2 U2 3 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JAN 10 PY 1997 VL 330 BP 141 EP 168 DI 10.1017/S0022112096003801 PG 28 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA WG787 UT WOS:A1997WG78700006 ER PT J AU Colonius, T Lele, SK Moin, P AF Colonius, T Lele, SK Moin, P TI Sound generation in a mixing layer SO JOURNAL OF FLUID MECHANICS LA English DT Article ID NONREFLECTING BOUNDARY-CONDITIONS; DIRECT COMPUTATION; SHEAR-LAYER; JET; NOISE; VORTEX; WAVES AB The sound generated by vortex pairing in a two-dimensional compressible mixing layer is investigated. Direct numerical simulations (DNS) of the Navier-Stokes equations are used to compute both the near-field region and a portion of the acoustic field. The acoustic analogy due to Lilley (1974) is also solved with acoustic sources determined from the near-field data of the DNS. It is shown that several commonly made simplifications to the acoustic sources can lead to erroneous predictions for the acoustic field, Predictions based on the quadrupole form of the source terms derived by Goldstein (1976a, 1984) are in excellent agreement with the acoustic field from the DNS. However, despite the low Mach number of the flow, the acoustic far field generated by the vortex pairings cannot be described by considering compact quadrupole sources. The acoustic sources have the form of modulated wave packets and the acoustic far field is described by a superdirective model (Crighton & Huerre 1990). The presence of flow-acoustic interactions in the computed source terms causes the acoustic field predicted by the acoustic analogy to be very sensitive to small changes in the description of the source. C1 STANFORD UNIV, DEPT MECH ENGN, STANFORD, CA 94305 USA. STANFORD UNIV, DEPT AERONAUT & ASTRONAUT, STANFORD, CA 94305 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Colonius, T (reprint author), CALTECH, DIV ENGN & APPL SCI, PASADENA, CA 91125 USA. NR 46 TC 162 Z9 172 U1 1 U2 18 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JAN 10 PY 1997 VL 330 BP 375 EP 409 DI 10.1017/S0022112096003928 PG 35 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA WG787 UT WOS:A1997WG78700016 ER PT J AU Rubincam, DP Currie, DG Robbins, JW AF Rubincam, DP Currie, DG Robbins, JW TI LAGEOS I once-per-revolution force due to solar heating SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SATELLITE; DYNAMICS; ORBIT AB Photon thrust from the solar heating of the LAGEOS I satellite appears to explain much of the eccentricity variations seen in the satellite's orbital elements. We invoke a thermal model of LAGEOS I in which the photon thrust from solar heating is directed along the satellite's spin axis and functionally depends only on the cosine of the angle between the Sun's position and the spin axis. We calibrated the amplitude of the force from the 1980-1983 equivalent along-track acceleration derived from the observed orbital perturbations; during this time the spin axis position is assumed to be known and to be that at orbit injection. The photon thrust from this simple thermal model, plus later spin axis positions obtained from Sun glint data (which show LAGEOS I to be precessing), give reasonable agreement with the observed along-track acceleration in the time period 1988-1995. Thus much of the eccentricity variations seem to be due to thermal thrust and do not have a geophysical origin (atmospheric tides) as has been proposed. However, our solar heating model does not appear to explain the highest peaks and deepest troughs seen in the along-track acceleration, indicating the need for a better thermal model and consideration of other forces, such as that due to anisotropic reflection. C1 UNIV MARYLAND, DEPT PHYS & ASTRON, ASTROMETROL GRP, COLLEGE PK, MD 20742 USA. HUGHES STX CORP, GREENBELT, MD 20770 USA. 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 17 TC 14 Z9 14 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 10 PY 1997 VL 102 IS B1 BP 585 EP 590 DI 10.1029/96JB02851 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WC628 UT WOS:A1997WC62800012 ER PT J AU James, TS Ivins, ER AF James, TS Ivins, ER TI Global geodetic signatures of the Antarctic ice sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DEEP MANTLE VISCOSITY; GLACIER DRAINAGE-BASIN; SEA-LEVEL; EARTHS ROTATION; MASS-BALANCE; GRAVITATIONAL-FIELD; POLAR ICE; GRAVITY-FIELD; RE-ASSESSMENT; CONSTRAINT AB Four scenarios of present day Antarctic ice sheet mass change are developed from comprehensive reviews of the available glaciological and oceanographic evidence. The gridded scenarios predict widely varying contributions to secular sea level change xi over dot ranging from -1.1 to 0.45 mm/yr, and predict polar motion m over dot and time-varying low-degree gravitational coefficients J(l) that differ significantly from earlier estimates. A reasonably linear relationship between the rate of sea level change from Antarctica xi over dot(A) and the predicted Antarctic J(l) is found for the four scenarios. This linearity permits a series of forward models to be constructed that incorporate the effects of ice mass changes in Antarctica, Greenland, and distributed smaller glaciers, as well as postglacial rebound (assuming the ICE-3G deglaciation history), with the goal of obtaining optimum reconciliation between observed constraints on J over dot(l) and sea level rise xi. Numerous viable combinations of lower mantle viscosity and hydrologic sources are found that satisfy ''observed'' xi over dot in the range of 1 to 2-2.5 mm/yr and observed J over dot (l) for degrees 2, 3, and 4. In contrast, rates of global sea level rise above 2.5 mm/yr are inconsistent with available J over dot (l) observations. The successful composite models feature a pair of lower mantle viscosity solutions arising from the sensitivity of J over dot (l) to glacial rebound. The paired values are well separated at xi over dot = 1 mm/yr, but move closer together as xi over dot is increased, and, in fact, merge around xi over dot = 2 - 2.5 mm/yr, revealing an intimate relation between xi over dot and preferred lower mantle viscosity. This general pattern is quite robust and persists for different J over dot (l) solutions, for variations in source assumptions, and for different styles of lower mantle viscosity stratification. Tighter J over dot (l) constraints for l > 2 may allow some viscosity stratification schemes and source assumptions to be excluded in the future. For a given total observed xi over dot, the sea level rise from Antarctica xi over dot (A) is tightly constrained and ranges from 0 to + 1 mm/yr (corresponding to an ablating ice sheet) as estimates of xi over dot are raised from 1 to 2.5 mm/yr. However, when the degree 3 zonal harmonic constraint is: removed, the solutions show little sensitivity to Antarctic mass balance, emphasizing the need for a well determined odd-degree secular zonal harmonic for determining polar ice mass balance. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP James, TS (reprint author), GEOL SURVEY CANADA, PACIFIC GEOSCI CTR, 9860 W SAANICH RD, SIDNEY, BC V8L 4B2, CANADA. RI James, Thomas/D-9301-2013 OI James, Thomas/0000-0001-7321-047X NR 74 TC 55 Z9 55 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 10 PY 1997 VL 102 IS B1 BP 605 EP 633 DI 10.1029/96JB02855 PG 29 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WC628 UT WOS:A1997WC62800014 ER PT J AU Leonard, PJT AF Leonard, PJT TI Gamma-ray astronomy - In line for a new mission SO NATURE LA English DT Editorial Material RP Leonard, PJT (reprint author), GODDARD SPACE FLIGHT CTR,COMPTON GAMMA RAY OBSERV SCI SUPPORT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD JAN 9 PY 1997 VL 385 IS 6612 BP 116 EP 117 DI 10.1038/385116a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WB728 UT WOS:A1997WB72800025 ER PT J AU Leonard, PJT AF Leonard, PJT TI Compton telescopes SO NATURE LA English DT Editorial Material RP Leonard, PJT (reprint author), GODDARD SPACE FLIGHT CTR,COMPTON GAMMA RAY OBSERV SCI SUPPORT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD JAN 9 PY 1997 VL 385 IS 6612 BP 117 EP 117 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WB728 UT WOS:A1997WB72800026 ER PT J AU Riotto, A Roulet, E Vilja, I AF Riotto, A Roulet, E Vilja, I TI Preheating and vacuum metastability in supersymmetry SO PHYSICS LETTERS B LA English DT Article ID LOW-ENERGY SUPERGRAVITY; PARTICLE-PRODUCTION; EARLY UNIVERSE; ENTROPY CRISIS; FALSE VACUA; INFLATION; BREAKING; EQUILIBRIUM; BARYOGENESIS; MODELS AB The constraints imposed by the requirement that the scalar potential of supersymmetric theories does not have unbounded directions and charge or color breaking minima deeper than the usual electroweak breaking minimum (EWM) are significantly relaxed if one just allows for a metastable EWM but with a sufficiently long lifetime. For this to be acceptable one needs however to explain how the vacuum state reaches this metastable configuration in the first place. We discuss the implications for this issue of the inflaton induced scalar masses, of the supersymmetry breaking effects generated during the preheating stage as well as of the thermal corrections to the scalar potential which appear after reheating. We show that their combined effects may efficiently drive the scalar fields to the origin, allowing them to then evolve naturally towards the EWM. C1 SCUOLA INT SUPER STUDI AVANZATI,SCH ADV INT STUDIES,I-34014 TRIESTE,ITALY. UNIV TURKU,DEPT PHYS,TURKU 20014,FINLAND. RP Riotto, A (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 48 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JAN 2 PY 1997 VL 390 IS 1-4 BP 73 EP 79 DI 10.1016/S0370-2693(96)01380-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WD164 UT WOS:A1997WD16400014 ER PT B AU Haeffelin, MPA Wong, T Young, DF AF Haeffelin, MPA Wong, T Young, DF GP AMS TI Temporal sampling errors in atmospheric and surface fluxes SO 10TH CONFERENCE ON APPLIED CLIMATOLOGY LA English DT Proceedings Paper CT 10th Conference on Applied Climatology CY OCT 20-23, 1997 CL RENO, NV SP Amer Meteorol Soc C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Haeffelin, MPA (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 80 EP 84 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK86P UT WOS:000073700700023 ER PT B AU Jeffries, DK Krishnamurthy, R Chandra, S AF Jeffries, DK Krishnamurthy, R Chandra, S BE Philip, T TI Two dimensional reaction control flow - A numerical study SO 10TH INTERNATIONAL CONFERENCE ON COMPUTER APPLICATIONS IN INDUSTRY AND ENGINEERING LA English DT Proceedings Paper CT 10th International Conference on Computer Applications in Industry and Engineering CY DEC 10-12, 1997 CL RAMADA EMILY MORGAN HOTEL, SAN ANTONIO, TX SP Int Soc Comp & Applicat HO RAMADA EMILY MORGAN HOTEL AB This study involves the numerical investigation of a normal sonic jet exhausting into a hypersonic cross-flow. Th: numerical code used for simulation is GASP (General Aerodynamic Simulation Program.) First the non-injection case of the problem was setup and results obtained. Numerical predictions are compared with well established solutions for compressible laminar flow. Then comparisons are made with non-injection test case measurements of surface pressure distributions. Good agreement with the measurements is observed. Next the injection case of the problem is developed from the non-injection model and results generated. The model is validated by comparison of numerical values with experimental injection surface pressure measurements. Good agreement with the injection experimental measurements was obtained. C1 N Carolina Agr & Technol State Univ, Coll Engn, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. RP Jeffries, DK (reprint author), N Carolina Agr & Technol State Univ, Coll Engn, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INTERNATIONAL SOCIETY COMPUTER S & THEIR APPLICATIONS (ISCA) PI RALEIGH PA 8820 SIX FORKS ROAD, RALEIGH, NC 27615 USA BN 1-880843-22-6 PY 1997 BP 29 EP 31 PG 3 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary SC Computer Science; Engineering GA BK86K UT WOS:000073699800008 ER PT B AU DelSole, T Hou, A AF DelSole, T Hou, A GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Modeling stationary climate statistics using empirical normal modes and singular vectors SO 11TH CONFERENCE ON ATMOSPHERIC AND OCEANIC FLUID DYNAMICS LA English DT Proceedings Paper CT 11th Conference on Atmospheric and Oceanic Fluid Dynamics CY JUN 23-27, 1997 CL TACOMA, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP DelSole, T (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. RI Hou, Arthur/D-8578-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 125 EP 126 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK05U UT WOS:000071010100037 ER PT B AU Ferreira, RN Schubert, WH AF Ferreira, RN Schubert, WH GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Tropical cyclone and circumpolar vortex interactions SO 11TH CONFERENCE ON ATMOSPHERIC AND OCEANIC FLUID DYNAMICS LA English DT Proceedings Paper CT 11th Conference on Atmospheric and Oceanic Fluid Dynamics CY JUN 23-27, 1997 CL TACOMA, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Ferreira, RN (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Mailstop 913-0, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 162 EP 165 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK05U UT WOS:000071010100047 ER PT B AU DelSole, T AF DelSole, T GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Absolute instability induced by dissipation SO 11TH CONFERENCE ON ATMOSPHERIC AND OCEANIC FLUID DYNAMICS LA English DT Proceedings Paper CT 11th Conference on Atmospheric and Oceanic Fluid Dynamics CY JUN 23-27, 1997 CL TACOMA, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP DelSole, T (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 313 EP 313 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK05U UT WOS:000071010100096 ER PT B AU Chou, SH AF Chou, SH GP AMER METEOROL SOC AMER METEOROL SOC AMER METEOROL SOC TI Multiple equilibria in asymmetrically dissipated baroclinic flows SO 11TH CONFERENCE ON ATMOSPHERIC AND OCEANIC FLUID DYNAMICS LA English DT Proceedings Paper CT 11th Conference on Atmospheric and Oceanic Fluid Dynamics CY JUN 23-27, 1997 CL TACOMA, WA SP Amer Meteorol Soc C1 NASA, Earth Syst Sci Div, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Chou, SH (reprint author), NASA, Earth Syst Sci Div, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 319 EP 321 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK05U UT WOS:000071010100098 ER PT S AU Lou, JZ Farrara, JD AF Lou, JZ Farrara, JD GP IEEE COMP SOC TI Performance analysis and optimization on a parallel atmospheric general circulation model code SO 11TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM, PROCEEDINGS SE INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM. PROCEEDINGS LA English DT Proceedings Paper CT 11th International Parallel Processing Symposium (IPPS 97) CY APR 01-05, 1997 CL GENEVA, SWITZERLAND SP IEEE Comp Soc Tech Comm Parallel Proc, Assoc Comp Machinery SIGARCH, European Assoc Theoret Comp Sci, Swiss SIPAR, SPEEDUP Soc AB An analysis is presented of the primary factors influencing the performance of a parallel implementation of the UCLA atmospheric general circulation model (AGCM) on distributed-memory, massively parallel computer systems. Several modifications to the original parallel AGCM code aimed at improving its numerical efficiency, load-balance and single-node code performance are discussed. The impact of these optimization strategies on the performance on two of the state-of-the-art parallel computers, the Intel Paragon and Gray T3D, is presented and analyzed. It is found that implementation of a load-balanced FFT algorithm results in a reduction in overall execution time of approximately 45% compared to the original convolution-based algorithm. Preliminary results of the application of a load-balancing scheme for the Physics part of the AGCM code suggest additional reductions in execution time of 15-20% can be achieved. Finally, several strategies for improving the single-node performance of the code are presented, and the results obtained thus far suggest reductions in execution time in the range of 30-40% are possible. RP Lou, JZ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91009, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 SN 1063-7133 BN 0-8186-7793-7 J9 IPPS PROC PY 1997 BP 174 EP 180 DI 10.1109/IPPS.1997.580879 PG 7 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BH56G UT WOS:A1997BH56G00025 ER PT S AU Truong, SH Hart, RC Shoan, WC Wood, T Long, AC Oza, DH Lee, T AF Truong, SH Hart, RC Shoan, WC Wood, T Long, AC Oza, DH Lee, T BE Guyenne, TD TI High accuracy autonomous navigation using the global positioning system (GPS) SO 12TH INTERNATIONAL SYMPOSIUM ON SPACE FLIGHT DYNAMICS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 12th International Symposium on Space Flight Dynamics CY JUN 02-06, 1997 CL ESOC, DARMSTADT, GERMANY SP European Space Agcy HO ESOC AB The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) is pursuing the application of Global Positioning System (GPS) technology to improve the accuracy and economy of spacecraft navigation. High-accuracy autonomous navigation algorithms are being flight qualified in conjunction with GSFC's GPS Attitude Determination Flyer (GADFLY) experiment on the Small Satellite Technology Initiative Lewis spacecraft, which is scheduled for launch in May 1997. Preflight performance assessments indicate that these algorithms can provide a real-time total position accuracy of better than 10 meters (1 sigma) and velocity accuracy of better than 0.01 meter per second (1 sigma), with selective availability at typical levels. This accuracy is projected to improve to the 2-meter level if corrections to be provided by the GPS Wide Area Augmentation System (WAAS) are included. RP Truong, SH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 3 U2 3 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-295-8 J9 ESA SP PUBL PY 1997 VL 403 BP 73 EP 78 PG 6 WC Engineering, Aerospace SC Engineering GA BJ70C UT WOS:A1997BJ70C00010 ER PT S AU Deutschmann, J BarItzhack, I AF Deutschmann, J BarItzhack, I BE Guyenne, TD TI Comprehensive evaluation of attitude and orbit estimation using real earth magnetic field data SO 12TH INTERNATIONAL SYMPOSIUM ON SPACE FLIGHT DYNAMICS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 12th International Symposium on Space Flight Dynamics CY JUN 02-06, 1997 CL ESOC, DARMSTADT, GERMANY SP European Space Agcy HO ESOC AB A single, augmented Extended Kalman Filter (EKF) which simultaneously and autonomously estimates spacecraft attitude and orbit has been developed and successfully tested with both simulated and real magnetometer and rate data. Since the earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computed and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both orbit and attitude errors. Therefore, these differences can be used to estimate both orbit and attitude. The results of testing the EKF with real magnetometer and gyro data from three satellites supported by the NASA Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) are presented and evaluated. RP Deutschmann, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,FLIGHT DYNAM DIV,CODE 552,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-295-8 J9 ESA SP PUBL PY 1997 VL 403 BP 173 EP 178 PG 6 WC Engineering, Aerospace SC Engineering GA BJ70C UT WOS:A1997BJ70C00025 ER PT S AU Riedel, JE Bhaskaran, S Synnott, SP Desai, SD Bollman, WE Dumont, PJ Halsell, CA Han, D Kennedy, BM Null, GW Owen, WM Werner, RA Williams, BG AF Riedel, JE Bhaskaran, S Synnott, SP Desai, SD Bollman, WE Dumont, PJ Halsell, CA Han, D Kennedy, BM Null, GW Owen, WM Werner, RA Williams, BG BE Guyenne, TD TI Navigation for the new millennium: Autonomous navigation for Deep Space 1 SO 12TH INTERNATIONAL SYMPOSIUM ON SPACE FLIGHT DYNAMICS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 12th International Symposium on Space Flight Dynamics CY JUN 02-06, 1997 CL ESOC, DARMSTADT, GERMANY SP European Space Agcy HO ESOC AB The first flight of NASA's New Millennium Program, Deep Space 1, will include a new navigational technology: an autonomous optical navigation system. The DSI Navigation system will be the first use of autonomous navigation in deep space. The task for this system is to 1) perform interplanetary cruise orbit determination, using images of distant asteroids, 2) control and maintain the orbit of the spacecraft using the ion propulsion system (another technology never before applied to deep space) and conventional thrusters, 3) perform approach orbit determination and control using images of the science targets, 4) perform late knowledge updates of target position during close fast flybys in order to facilitate a high degree of quality data return from 2 targets: asteroid McAuliffe and comet West-Kohoutek-Ikemura. Additionally, an encounter with Mars will probably be performed with possibly a close flyby of one of the Martian moons, Phobos or Deimos. Several functional components are necessary to accomplish these tasks. These include picture planning and image processing, dynamical modeling and integration, planetary ephemeris and star catalog handling, orbit determination data filtering and estimation, maneuver estimation, spacecraft ephemeris updates and maintenance, and general interaction with the other onboard autonomous systems. These systems are described, as is the means of their operation onboard. Finally, performance statistics from trial runs of the system are given. RP Riedel, JE (reprint author), CALTECH,JET PROP LAB,NAVIGAT & FLIGHT MECH SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-295-8 J9 ESA SP PUBL PY 1997 VL 403 BP 303 EP 320 PG 18 WC Engineering, Aerospace SC Engineering GA BJ70C UT WOS:A1997BJ70C00044 ER PT S AU Wilson, MG Potts, CL Mase, RA Halsell, CA Byrnes, DV AF Wilson, MG Potts, CL Mase, RA Halsell, CA Byrnes, DV BE Guyenne, TD TI Maneuver design for Galileo Jupiter approach and orbital operations SO 12TH INTERNATIONAL SYMPOSIUM ON SPACE FLIGHT DYNAMICS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 12th International Symposium on Space Flight Dynamics CY JUN 02-06, 1997 CL ESOC, DARMSTADT, GERMANY SP European Space Agcy HO ESOC AB Following the successful release of the Galileo Probe in July of 1995, navigation efforts focused on implementing the critical Io approach and Jupiter orbit insertion strategy that had been refined over the previous decade. Actual events on approach would significantly alter these plans. The most significant event affecting the navigation plan was an onboard tape recorder anomaly, which, as will be shown, would have a profound effect on the plans and assumptions of the navigation strategy for approach and orbit insertion. This paper addresses the analysis, constraints, contingency planning and design evolution of trajectory correction maneuvers enabling the completion of these events, which lead to the first ever atmospheric entry Probe and Orbiter of an outer planet. An analysis of the original navigation plan is presented to verify the viability of that strategy under nominal circumstances. A presentation of orbital phase performance and future mission operations plans is also included. RP Wilson, MG (reprint author), CALTECH,JET PROP LAB,NAVIGAT & FLIGHT MECH SECT,4800 OAK GROVE DR,M-S 301-276,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-295-8 J9 ESA SP PUBL PY 1997 VL 403 BP 341 EP 349 PG 9 WC Engineering, Aerospace SC Engineering GA BJ70C UT WOS:A1997BJ70C00048 ER PT S AU Esposito, P Alwar, V Demcak, S Giorgini, J Graat, E Johnston, M AF Esposito, P Alwar, V Demcak, S Giorgini, J Graat, E Johnston, M BE Guyenne, TD TI Navigation and the Mars Global Surveyor mission SO 12TH INTERNATIONAL SYMPOSIUM ON SPACE FLIGHT DYNAMICS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 12th International Symposium on Space Flight Dynamics CY JUN 02-06, 1997 CL ESOC, DARMSTADT, GERMANY SP European Space Agcy HO ESOC AB The Mars Global Surveyor (MGS) spacecraft was successfully launched from Cape Canaveral by a Delta II 7925 rocket on 11/7/96, 17:00:50 UTC. Injection into the trans-Mars trajectory went smoothly with the achieved or reconstructed injection targeting within 1.3 sigma of the planned targeting. As of 6/1/97, we are 205 days into the mission. Two trajectory correction maneuvers (TCM-1 and TCM-2) were successfully completed on 11/21/96 and 3/20/97. TCM-3, which was to have occurred on 4/22/97, was cancelled because of the accuracy of previous targeting. The final TCM shall occur on 8/25/97 in order to adjust arrival conditions for the Mars Orbit Insertion (MOI) maneuver which shall occur on 9/12/97. The planned capture orbit is highly elliptical with a 45 hour orbital period, a 300 km periapsis altitude and a descending node at 5:43 pm local mean solar time. Two-way coherent doppler (range-rate) and time-delay (range) measurements, at an X-band frequency (8.4 GHz), are being acquired by Deep Space Network (DSN) stations near Goldstone, California, Madrid, Spain and Canberra, Australia. These data are being used to navigate the spacecraft. Representative data noise or precision is 0.85 mHz (0.015 mm/s in range-rate), over a ten minute count-time, for the doppler and 0.4 meters for the range data. After capture, the orbit shall be circularized by aerobraking (AB) and propulsive maneuvers. AB is divided into three phases: a) a cautious ''walk-in'' period in which the periapsis altitude is lowered from 300 km to 110 km, b) the main phase in which most of the orbital circularization occurs, and c) the walk-out phase during which the spacecraft steps out of the atmosphere and the mapping orbit is established by two propulsive maneuvers. With the initiation of the mapping phase on 3/15/98, science data acquisition shall be continuous for one Mars year or 687 earth days. Navigation shall maintain a 2:00 pm descending node, sun-synchronous, low altitude, short periodic and ''frozen'' orbit throughout this time. In addition, the ground track coverage shall be nearly uniform in order to maximize data acquisition from the nadir pointed science instruments. From Feb 2000 to Jan 2003, a relay phase shall be established during which MGS shall be available as a relay satellite for the Mars '98 rover mission. RP Esposito, P (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-295-8 J9 ESA SP PUBL PY 1997 VL 403 BP 371 EP 376 PG 6 WC Engineering, Aerospace SC Engineering GA BJ70C UT WOS:A1997BJ70C00053 ER PT B AU Meier, DL Edgington, S Godon, P Payne, DG Lind, KR AF Meier, DL Edgington, S Godon, P Payne, DG Lind, KR BE Clarke, DA West, MJ TI Simulations of jet production in magnetized accretion disk coronae SO 12TH KINGSTON MEETING : COMPUTATIONAL ASTROPHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 12th Kingston Meeting on Theoretical Astrophysics CY OCT 17-19, 1996 CL HALIFAX, CANADA AB We describe the results of over 40 MHD simulations, performed on Caltech/JPL parallel supercomputers, of the coronae of magnetized accretion disks around compact objects. All produce some type. of outflow from the disk. Our parameter study investigated the character of the outflow as a function of the strength of the initial poloidal magnetic field and its angle with respect to the disk rotation axis. When the radial component of the field is significant, this outflow takes the form of a collimated jet ejected from tie center of the accretion disk. The jet velocity is a strong function of the strength of the initial, magnetic field: for Alfven velocities (V-A) below the escape speed (V-esc), the jet velocity is of order V-A, but for V-A only slightly above V-esc, the jet Velocity is an order of magnitude or more greater. This "magnetic switch" behaves similarly for a broad range of magnetic field polar angle. However, when the initial coronal magnetic field is nearly completely dominated by an axial component, the importance of the central jet diminishes and the outflow becomes dominated by a poorly-collimated wind from a broader region of the accretion disk. The magnetic switch may have applications to galactic and extragalactic radio sources and other objects. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-43-0 J9 ASTR SOC P PY 1997 VL 123 BP 290 EP 295 PG 6 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80C UT WOS:000073443000042 ER PT B AU Brown, LR Crisp, JA Crisp, D Perrin, A Naumenko, OV Smirnov, MA Sinitsa, LN AF Brown, LR Crisp, JA Crisp, D Perrin, A Naumenko, OV Smirnov, MA Sinitsa, LN BE Sinitsa, LN Ponomarev, YN Perevalov, VI TI High resolution Fourier transform spectrum of H2S in the 2150-4260 cm(-1) region SO 12TH SYMPOSIUM AND SCHOOL ON HIGH-RESOLUTION MOLECULAR SPECTROSCOPY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 12th Symposium & School on High-Resolution Molecular Spectroscopy CY JUL 01-05, 1996 CL ST PETERSBURG, RUSSIA SP Russian Fdn Basic Res, Russian Federat Higher Educ, State Comm, Soc Photo Opt Instrumentat Engineers, Soc Photo Opt Instrumentat Engineers, Russia Chapter, Russian Acad Sci, Inst Atmospher Opt, Russian Acad Sci, Gen Phys Inst, St Petersburg State Univ, Russian Acad Sci, Sci Council Spectroscopy, Russian Acad Sci, Working Grp Atmospher Spectroscopy Radiat Commiss RP Brown, LR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2505-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3090 BP 108 EP 110 DI 10.1117/12.267744 PG 3 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BH32Q UT WOS:A1997BH32Q00018 ER PT B AU Brown, LR Crisp, JA Crisp, D Naumenko, OV Smirnov, MA Sinitsa, LN AF Brown, LR Crisp, JA Crisp, D Naumenko, OV Smirnov, MA Sinitsa, LN BE Sinitsa, LN Ponomarev, YN Perevalov, VI TI The first hexad of interacting states of H2S molecule. SO 12TH SYMPOSIUM AND SCHOOL ON HIGH-RESOLUTION MOLECULAR SPECTROSCOPY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 12th Symposium & School on High-Resolution Molecular Spectroscopy CY JUL 01-05, 1996 CL ST PETERSBURG, RUSSIA SP Russian Fdn Basic Res, Russian Federat Higher Educ, State Comm, Soc Photo Opt Instrumentat Engineers, Soc Photo Opt Instrumentat Engineers, Russia Chapter, Russian Acad Sci, Inst Atmospher Opt, Russian Acad Sci, Gen Phys Inst, St Petersburg State Univ, Russian Acad Sci, Sci Council Spectroscopy, Russian Acad Sci, Working Grp Atmospher Spectroscopy Radiat Commiss RP Brown, LR (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 3 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2505-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3090 BP 111 EP 113 DI 10.1117/12.267745 PG 3 WC Optics; Spectroscopy SC Optics; Spectroscopy GA BH32Q UT WOS:A1997BH32Q00019 ER PT B AU Das, S AF Das, S GP AMS TI Cloud top entrainment instability in a prognostic cloud scheme for large scale models SO 12TH SYMPOSIUM ON BOUNDARY LAYERS AND TURBULENCE LA English DT Proceedings Paper CT 12th Symposium on Boundary Layers and Turbulence CY JUL 28-AUG 01, 1997 CL VANCOUVER, CANADA SP Amer Meteorol Soc (AMS), Canadian Meteorol & Oceanographic Soc C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Das, S (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 913, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 78 EP 79 PG 2 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA BL60X UT WOS:000075999700040 ER PT B AU Ying, RX Canuto, VM AF Ying, RX Canuto, VM GP AMS TI Simulation of flow over two-dimensional hills using second-order closure turbulence model SO 12TH SYMPOSIUM ON BOUNDARY LAYERS AND TURBULENCE LA English DT Proceedings Paper CT 12th Symposium on Boundary Layers and Turbulence CY JUL 28-AUG 01, 1997 CL VANCOUVER, CANADA SP Amer Meteorol Soc (AMS), Canadian Meteorol & Oceanographic Soc C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Ying, RX (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 522 EP 523 PG 2 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA BL60X UT WOS:000075999700264 ER PT S AU Schmidlin, FJ McCarthy, S Michel, W Ross, ED AF Schmidlin, FJ McCarthy, S Michel, W Ross, ED BE KaldeichSchurmann, B TI Vertical ozone profile comparisons between ozonesondes and remote instrumentation SO 13TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS: EUROPEAN SPACE AGENCY PROGRAMME ADVISORY COMMITTEE (PAC) ON THE SPECIAL PROJECT CONCERNING THE LAUNCHING OF SOUNDING ROCKETS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 13th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY MAY 26-29, 1997 CL OLAND, SWEDEN SP European Space Agey, Swedish Natl Space Board AB Ozonesonde measurement quality is a critical factor for insuring measurement accuracy and is fundamentally indispensable for validating remotely measured ozone. Reasonable results from such ozone profile comparisons are best obtained by maintaining the smallest possible spatial and time differences between ozonesonde and remote measurement observations. Ozone profiles measured with the Halogen Occultation Experiment (HALOE) instrument and the Microwave Limb Sounder (MLS) instrument on NASA's Upper Atmosphere Research Satellite (UARS) are compared with ECC profiles. Comparisons with the GSFC ozone lidar also demonstrate good agreement. In this paper we show 1) the process used by NASA to secure quality ozonesonde measurements, 2) comparisons of ozonesondes with various remote sensing instruments and, 3) the reliability obtained when both measurement types are obtained close in time and, when possible, in space. RP Schmidlin, FJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,WALLOPS FLIGHT FACIL,OBSERVAT SCI BRANCH,LAB HYDROSPHER PROC,WALLOPS ISL,VA 23337, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-271-0 J9 ESA SP PUBL PY 1997 VL 397 BP 169 EP 173 PG 5 WC Engineering, Aerospace; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA BJ82Y UT WOS:A1997BJ82Y00025 ER PT S AU Hudson, SM AF Hudson, SM BE KaldeichSchurmann, B TI Mobile range control center range safety command destruct & real-time instantaneous impact prediction system SO 13TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS: EUROPEAN SPACE AGENCY PROGRAMME ADVISORY COMMITTEE (PAC) ON THE SPECIAL PROJECT CONCERNING THE LAUNCHING OF SOUNDING ROCKETS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 13th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY MAY 26-29, 1997 CL OLAND, SWEDEN SP European Space Agey, Swedish Natl Space Board DE launch vehicles; Mobile Range Control Center Range Safety Command Destruct & Real-Time Instantaneous Impact Prediction System (MRCCS); remote launch sites AB Scientific, military and commercial space requirements necessitate launching sounding rockets and expendable launch vehicles from remote sites throughout the world. To meet these challenges, the National Aeronautics and Space Administration's Goddard Space Flight Center at Wallops Flight Facility (NASA/GSFC/WFF) Wallops Flight Facility has designed and implemented a Mobile Range Control Center/Range Safety Command Destruct & Real-Time Instantaneous Impact Prediction System (MRCCS). The MRCCS provides mission control and range safety support for remote launch sites and is equipped with telemetry and radar data acquisition systems, real-time data computation systems, range safety display systems and command destruct transmitters. The MRCCS is a fully redundant and self-contained unit. The MRCCS was certified for operational support in August, 1996. The MRCCS was stationed in the Canary Islands to support the Spanish MINISAT Pegasus mission. This mobile system is also scheduled to support the NASA X-33 Project during 1998 and 1999. RP Hudson, SM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,FLIGHT SAFETY SECT 821,WALLOPS FLIGHT FACIL,WALLOPS ISL,VA 23337, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-271-0 J9 ESA SP PUBL PY 1997 VL 397 BP 271 EP 274 PG 4 WC Engineering, Aerospace; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA BJ82Y UT WOS:A1997BJ82Y00042 ER PT S AU Goldberg, RA Desch, MD Farrell, WM AF Goldberg, RA Desch, MD Farrell, WM BE KaldeichSchurmann, B TI The UAV: A unique platform for electrodynamic studies of upward lightning in the middle atmosphere SO 13TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS: EUROPEAN SPACE AGENCY PROGRAMME ADVISORY COMMITTEE (PAC) ON THE SPECIAL PROJECT CONCERNING THE LAUNCHING OF SOUNDING ROCKETS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 13th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY MAY 26-29, 1997 CL OLAND, SWEDEN SP European Space Agey, Swedish Natl Space Board AB Recent research has helped identify, define, and describe the occurrence of transient electrical bursts (similar to 10-20 ms duration) in the stratosphere and mesosphere during tropospheric electrical storms. These phenomena are termed blue jets and red sprites to describe their appearance on color video photography. Both phenomena have been observed aboard aircraft flights and from ground-based observatories in Colorado, but have not been studied in sufficient detail to provide information about the electrodynamic characteristics surrounding their occurrence. Furthermore, such observations have up to now been remote to the event site. However, it is critical to make in situ measurements within the active electrical region for the primary purpose of understanding the currents responsible for the luminous events, to develop a proper understanding of their cause(s), and of their impact on the atmospheric electrical environment. The transfer of significant quantities of energy between the lower and upper atmosphere during tropospheric electrical storms has long been suspected but never verified until the identification of these type phenomena. It now becomes important to develop measuring systems which can be used to determine the mechanisms responsible for generating these events, to make abetter appraisal of their role and importance in the electrical structure of the atmosphere. RP Goldberg, RA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,EXTRATERR PHYS LAB,CODE 690,GREENBELT,MD 20771, USA. RI Goldberg, Richard /E-1881-2012; Farrell, William/I-4865-2013 NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-271-0 J9 ESA SP PUBL PY 1997 VL 397 BP 317 EP 323 PG 7 WC Engineering, Aerospace; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA BJ82Y UT WOS:A1997BJ82Y00050 ER PT S AU Ramsey, BD Peskov, V Kolodziejczak, JJ AF Ramsey, BD Peskov, V Kolodziejczak, JJ BE DelGuerra, A TI A study of factors limiting the maximum gain in microstrip gas counters SO 1996 IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, VOLS 1-3 SE IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD LA English DT Proceedings Paper CT 1996 IEEE Nuclear Science Symposium and Medical Imaging Conference CY NOV 02-09, 1996 CL ANAHEIM, CA SP IEEE AB It was shown in our previous paper [1] that the maximum achievable gain in Microstrip Gas Counters (MSGC's) is limited by surface streamers, which are self-quenched over a very limited voltage region and quickly transit to breakdown sparks. In this work we have tried to identify the main factors governing the maximum gain at which the streamers appear and towards this end have made simulations and tested MSGC's of different geometry on different substrates in both Ar- and Xe- based gas mixtures at pressures from 0.1 to 3 atm. From these studies we conclude that in order to reduce contributions of surface breakdown in MSGC's, multiplication should be concentrated to the narrowest region around the anode strips and the gas gain elsewhere, especially near the cathodes, should be maximally suppressed. For this purpose narrow anodes and gas mixtures with proper Townsend coefficients should be used. Control experiments we performed confirm these hypotheses. RP Ramsey, BD (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1082-3654 BN 0-7803-3535-X J9 IEEE NUCL SCI CONF R PY 1997 BP 229 EP 233 PG 5 WC Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BH59W UT WOS:A1997BH59W00049 ER PT S AU Bolotnikov, A Ramsey, B AF Bolotnikov, A Ramsey, B BE DelGuerra, A TI An attempt at using TMA to improve the energy resolution of high-pressure Xe ionization chambers SO 1996 IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, VOLS 1-3 SE IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD LA English DT Proceedings Paper CT 1996 IEEE Nuclear Science Symposium and Medical Imaging Conference CY NOV 02-09, 1996 CL ANAHEIM, CA SP IEEE AB Preliminary results of using TMA (trimethylamine) to improve the energy resolution of a high-pressure (>50 atm) Xe ionization chamber are presented. This work borrowed a technique which has been successfully applied to dope liquid Ar and Xe. However, problems related to the contamination of TMA were found to be more difficult to overcome. The maximum density of Xe at which the influence of impurities could be neglected was only 0.3 g/cm(3) at a concentration of TMA of about 80 ppm. As in the case of liquid Xe, doping increases the collected charge and considerably improves energy resolution, but only at low fields. RP Bolotnikov, A (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1082-3654 BN 0-7803-3535-X J9 IEEE NUCL SCI CONF R PY 1997 BP 667 EP 669 PG 3 WC Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA BH59W UT WOS:A1997BH59W00146 ER PT B AU Yuan, B Zrilic, DG AF Yuan, B Zrilic, DG BE Isik, C Cross, V TI An intelligent fuzzy control system SO 1997 ANNUAL MEETING OF THE NORTH AMERICAN FUZZY INFORMATION PROCESSING SOCIETY - NAFIPS LA English DT Proceedings Paper CT 1997 Annual Meeting of the North-American-Fuzzy-Information-Processing-Society (NAFIPS 97) CY SEP 21-24, 1997 CL SYRACUSE, NY SP N Amer Fuzzy Informat Proc Soc AB In this paper, we propose a new architecture of an intelligent fuzzy control system. The basic idea of the system is based on analyzing error responses of a fuzzy control system to adjust its parameters properly. Two simulation results have shown that the proposed system is promising. RP Yuan, B (reprint author), NEW MEXICO HIGHLANDS UNIV,DEPT ENGN,NASA,CTR AUTONOMOUS CONTROL ENGN,LAS VEGAS,NM 87701, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4078-7 PY 1997 BP 51 EP 56 DI 10.1109/NAFIPS.1997.624010 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics SC Computer Science GA BJ66E UT WOS:A1997BJ66E00010 ER PT B AU Blom, R Crippen, R Elachi, C Clapp, N Zarins, J Hedges, GR AF Blom, R Crippen, R Elachi, C Clapp, N Zarins, J Hedges, GR GP IEEE TI Space technology and the discovery of the lost city of Ubar SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The location of the legendary city of Ubar, a desert caravansary which supported the ancient and lucrative frankincense trade, has likely been found at the edge of the Arabian Peninsula's Empty Quarter in modem day Oman. Legend was that Ubar perished in a sandstorm as divine punishment for wicked living. Actually, much of the fortress collapsed into a sinkhole, perhaps undermined by extensive ground water withdrawal used to irrigate the surrounding oasis. The archaeological site was located by an unusual combination of historical research and the application of space technology in support of traditional archaeology. RP Blom, R (reprint author), CALTECH,JET PROP LAB,MAIL STOP 300-233,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 19 EP 28 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00002 ER PT B AU Peng, CY Tsang, SK Smith, K Sabahi, D Short, K Mauritz, A AF Peng, CY Tsang, SK Smith, K Sabahi, D Short, K Mauritz, A GP IEEE TI Model correlation for Mars Pathfinder entry, descent and landing simulation SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB Two multi-body drop tests were conducted to provide data to calibrate and verify a multi-body dynamics computer model, which was the major analytical tool used to study the entry, descent and landing (EDL) of the Mars Pathfinder mission. A general summary of the tests and important features of the simulation model are presented in this paper. good correlation between test results and analytical predictions were achieved. This confirmed the validity and accuracy of the model used for a subsequent extensive Monte Carlo effort to study the dynamics of the EDL under various spacecraft configurations and Martian environmental conditions. RP Peng, CY (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 233 EP 246 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00017 ER PT B AU Braun, RD Mitcheltree, RA Cheatwood, FM AF Braun, RD Mitcheltree, RA Cheatwood, FM GP IEEE TI Mars microprobe entry analysis SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The Mars Microprobe mission will provide the first opportunity for subsurface measurements, including water detection, near the south pole of Mars. In this paper, performance of the Microprobe aeroshell design is evaluated through development of a six-degree-of-freedom (6-DOF) aerodynamic database and flight dynamics simulation. Numerous mission uncertainties are quantified and a Monte-Carlo analysis is performed to statistically assess mission performance. Results from this 6-DOF Monte-Carlo simulation demonstrate that, in a majority of the cases (approximately 2-sigma), the penetrator impact conditions are within current design tolerances. Several trajectories are identified in which the current set of impact requirements are not satisfied. From these cases, critical design parameters are highlighted and additional system requirements are suggested. In particular, a relatively large angle-of-attack range near peak heating is identified. RP Braun, RD (reprint author), NASA,LANGLEY RES CTR,SPACE SYST & CONCEPTS DIV,MAIL STOP 365,HAMPTON,VA 23681, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 247 EP 262 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00018 ER PT B AU Coleman, M Peng, CY Smith, KS AF Coleman, M Peng, CY Smith, KS GP IEEE TI Test verification of the Cassini spacecraft dynamic model SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The Cassini spacecraft mission to Saturn will be launched in October 6, 1997 on a Titan IV/Centaur launch vehicle. Cassini is the largest interplanetary spacecraft ever developed. The purpose of the mission is to release a Probe through the atmosphere of Titan, while the spacecraft remains in orbit around Saturn. Before launch approval can be obtained, a test verified finite element model of the Cassini spacecraft must be completed and approved by NASA. The correctness of this model is critical to the final verification coupled loads analysis and margin of safety assessments. Modal surveys were performed in August 1995 and January 1996 on a Cassini test article to provide experimental data for the verification of the Cassini test analytical model (TAM). In addition to the modal surveys, static test and component sine swept test results were also used to corroborate analytical model results. Since the Cassini spacecraft is a complex system with numerous components taking part in global modes, a systematic approach was developed to complete the model verification task. The model verification strategy included the selection of modal survey test modes, correlation goals, and the model updating approach based on hardware knowledge, engineering judgment, and analytical methods to produce the final test correlated finite element model. The analytical approach used sensitivity to select optimum incremental improvements to the model parameters, solving an eigenvalue problem to compute the modal properties of the updated model. This method made it possible to vary many model parameters in unison to obtain good agreement between test and analytical modes, especially for complicated global modes. Through the implementation of these various tools, the Cassini spacecraft model was successfully correlated to test verification goals. RP Coleman, M (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 1 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 289 EP 299 PG 3 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00022 ER PT B AU Muscettola, N Fry, C Rajan, K Smith, B Chien, S Rabideau, G Yan, D AF Muscettola, N Fry, C Rajan, K Smith, B Chien, S Rabideau, G Yan, D GP IEEE TI On-board planning for New Millennium Deep Space One autonomy SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The Deep Space One (DS1) mission, scheduled to fly in 1998, will be the first NASA spacecraft to feature an on-board planner. The planner is part of an artificial intelligence based control architecture that comprises the planner/scheduler, a plan execution engine, and a model-based fault diagnosis and reconfiguration engine. This autonomy architecture reduces mission costs and increases mission quality by enabling high-level commanding, robust fault responses, and opportunistic responses to serendipitous events. This paper describes the on-board planning and scheduling component of the DS1 autonomy architecture. RP Muscettola, N (reprint author), NASA,AMES RES CTR,DEPT COMPUTAT SCI,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 303 EP 318 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00023 ER PT B AU Gat, E AF Gat, E GP IEEE TI ESL: A language for supporting robust plan execution in embedded autonomous agents SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB ESL (Execution Support Language) is a language for encoding execution knowledge in embedded autonomous agents. It is similar in spirit to RAPs [2] and RPL [7], and RS [6], and its design owes much to these systems. Unlike its predecessors, ESL aims for a more utilitarian point in the design space. ESL was designed primarily to be a powerful and easy-to-use tool, not to serve as a representation for automated reasoning or formal analysis (although nothing precludes its use for these purposes). ESL consists of several sets of loosely coupled features that can be composed in arbitrary ways. It is currently implemented as a set of extensions to Common Lisp, and is being used to build the executive component of a control architecture for an autonomous spacecraft [8]. RP Gat, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 319 EP 324 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00024 ER PT B AU Rabideau, G Chien, S Mann, T Eggemeyer, C Willis, J Siewert, S AF Rabideau, G Chien, S Mann, T Eggemeyer, C Willis, J Siewert, S GP IEEE TI Interactive, repair-based planning and scheduling for shuttle payload operations SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This paper describes the DATA-CHASER Automated Planner/Scheduler (DCAPS) system for automatically generating low-level command sequences from high-level user goals. DCAPS uses Artificial Intelligence (AI)-based search techniques and an iterative Automated repair framework in which the system architecture selectively resolves conflicts with the resource interactive and temporal constraints of the DATA-CHASER shuttle payload activities. RP Rabideau, G (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 325 EP 341 PG 3 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00025 ER PT B AU Chien, S Govindjee, A Estlin, T Wang, X Hill, R AF Chien, S Govindjee, A Estlin, T Wang, X Hill, R GP IEEE TI Automated generation of tracking plans for a network of communications antennas SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This paper describes the Deep Space Network Antenna Operations Planner (DPLAN) : a system that automatically generates antenna tracking plans for a set of highly sensitive radio science and telecommunications antennas. DPLAN inputs current equipment configuration information and a set of requested antenna track services. The system then uses a knowledge base of antenna operations procedures to produce a plan of activities that will provide the requested services using the allocated equipment. DPLAN produces this plan using an integration of artificial intelligence (AI) techniques, specifically, 'hierarchical task network (HTN) and operator-based planning. In this paper, we describe the antenna automation problem, the DPLAN system for automatic generation of track plans, DPLAN's current deployment status, and planned future work. RP Chien, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 525-3660,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 343 EP 359 PG 5 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00026 ER PT B AU Chien, S Lam, R Vu, Q AF Chien, S Lam, R Vu, Q GP IEEE TI Resource scheduling for a network of communications antennas SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This paper describes the Demand Access Network Scheduler (DANS) system for automatically scheduling and rescheduling resources for a network of communications antennas. DANS accepts a baseline schedule and supports rescheduling of antenna and subsystem resources to satisfy tracking goals in the event of: changing track requests, equipment outages, and inclement weather. RP Chien, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 525-3660,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 361 EP 373 PG 3 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00027 ER PT B AU Fukunaga, A Rabideau, G Chien, S Yan, D AF Fukunaga, A Rabideau, G Chien, S Yan, D GP IEEE TI Towards an application framework for automated planning and scheduling SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB A number of successful applications of automated planning and scheduling applications to spacecraft operations have recently been reported in the literature. However, these applications have been one-of-a-kind applications that required a substantial amount of development effort. In this paper, we describe ASPEN (Automated Planning/Scheduling Environment), a modular, reconfigurable application framework which is capable of supporting a wide variety of planning and scheduling applications. We describe the architecture of ASPEN, as well as a number of current spacecraft control/operations applications in progress. RP Fukunaga, A (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,M-S 525-3660,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 375 EP 386 PG 4 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00028 ER PT B AU Stolorz, P Gor, V Doyle, R Chapman, C Gladstone, R Merline, W Stern, A AF Stolorz, P Gor, V Doyle, R Chapman, C Gladstone, R Merline, W Stern, A GP IEEE TI New directions in science-enabling autonomy for planetary missions SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 1 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB Autonomy concepts now exert powerful influence on the development of a wide range of aerospace systems. Their value for automating spacecraft functions such as guidance, navigation and control is well-recognized. However, relatively little effort has been devoted in the past to their use in the context of payload data processing and understanding. In this paper, we focus on the use of autonomy to enable and enhance scientific goals for spaceborne missions. We argue that the general notions of autonomy can be applied directly to a broad range of scientific problems in ways that have never before been considered. We begin by outlining our general philosophy, and by describing the ways in which autonomy can be used to transform the ways in which spaceborne science is conducted. This is followed by a description of two novel systems that we have developed to exploit this philosophy for planetary missions. RP Stolorz, P (reprint author), CALTECH,JET PROP LAB,INFORMAT & COMP TECHNOL RES SECT,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 J9 AEROSP CONF PROC PY 1997 BP 387 EP 399 PG 5 WC Engineering, Aerospace SC Engineering GA BH30K UT WOS:A1997BH30K00029 ER PT B AU Ridge, D Becker, D Merkey, P Sterling, T AF Ridge, D Becker, D Merkey, P Sterling, T GP IEEE TI Beowulf: Harnessing the power of parallelism in a Pile-of-PCs SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The rapid increase in performance of mass market commodity microprocessors and significant disparity in pricing between PCs and scientific workstations has provided an opportunity for substantial gains in performance to cost by harnessing PC technology in parallel ensembles to provide high end capability for scientific and engineering applications. The Beowulf project is a NASA initiative sponsored by the HPCC program to explore the potential of Pile-of-PCs and to develop the necessary methodologies to apply these low cost system configurations to NASA computational requirements in the Earth and space sciences. Recently, a 16 processor Beowulf costing less than $50,000 sustained 1.25 Gigaflops on a gravitational N-body simulation of 10 million particles with a Tree code algorithm using standard commodity hardware and software components. This paper describes the technologies and methodologies employed to achieve this breakthrough. Both opportunities afforded by this approach and the challenges confronting its application to real-world problems are discussed in the framework of hardware and software systems as well as the results from benchmarking experiments. Finally, near term technology trends and future directions of the Pile-of-PCs concept are considered. RP Ridge, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,USRA CTR EXCELLENCE SPACE DATA & INFORMAT SCI,CODE 930-5,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 79 EP 91 PG 13 WC Engineering, Aerospace SC Engineering GA BH30L UT WOS:A1997BH30L00003 ER PT B AU Eisenman, AR Liebe, CC Jorgensen, JL Jensen, GB AF Eisenman, AR Liebe, CC Jorgensen, JL Jensen, GB GP IEEE TI Realization of a faster, cheaper, better star tracker for the new millennium SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The Advanced Stellar Compass (ASC) is a second generation star tracker consisting of a CCD camera and its associated microcomputer. It is a true, multi-star tracker which was designed for the Orsted mission, a precision mapper of the Earth's magnetic field. The ASC operates by matching the star images acquired by the camera to internal star catalogs. An initial attitude acquisition (solving the lost in space problem) is performed, and then the attitude of the camera is calculated in celestial coordinates by averaging the position of a large number of star observations for each image. The ASC features high accuracy, a smooth response to changing star fields, high boresight stability, low power and mass, robust autonomy, quaternion output and low cost. It is readily adapted to a wide range of missions, four of which are cited. Key parameters of the ASC for the Orsted and Astrid II satellites are: mass as low as 900 g; power consumption as low as 5.5 W; a single axis, relative, attitude angle error of less than 1.4 arcsec, RMS (which is close to 1 sigma) and a twist, or roll angle, relative accuracy of less than 13 arcsec, RMS, as measured at the Mauna Kea, Hawaii observatories of the University of Hawaii in June 1996. RP Eisenman, AR (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 327 EP 336 PG 10 WC Engineering, Aerospace SC Engineering GA BH30L UT WOS:A1997BH30L00019 ER PT B AU Sepahban, S Petri, D Frank, K AF Sepahban, S Petri, D Frank, K GP IEEE TI International space station end-to-end GN&C integration and development testing SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB To address some of the risks associated with the early integration and testing of the International Space Station (ISS) Guidance, Navigation, and Control (GN&C) system, the GN&C Integration Test Facility (GITF) at JSC was developed. The GITF is the only facility in the world capable of functional integration and end-to-end hardware in the loop testing of U.S. and Russian GN&C hardware and software, including their interfaces with the command and control (C&C) system. This paper elaborates on facility architecture and design decisions, testing phases, challenges, and potential future applications of GITF. RP Sepahban, S (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. OI Petri, Dario/0000-0002-9739-4469 NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 357 EP 368 PG 12 WC Engineering, Aerospace SC Engineering GA BH30L UT WOS:A1997BH30L00021 ER PT B AU Krasner, SM Bernard, DE AF Krasner, SM Bernard, DE GP IEEE TI Integrating autonomy technologies into an embedded spacecraft system - Flight software system engineering for new millennium SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB Deep Space 1 (DS1) is the first deep-space mission of NASA's New Millennium technology validation program. The DS1 flight software will validate five autonomy technologies: 1) Planner/Scheduler, which receives ground or on-board requests for spacecraft activities and schedules them to resolve any resource conflicts or timing constraints; 2) Smart Executive, which expands planned activities into lower-level commands, deduces required hardware configurations or other actions, and provides detection and avoidance of constraint violations; 3) Mode Identification and Reconfiguration engine, which incorporates models of hardware and software behavior, detects discrepancies due to hardware or software failures, and requests recovery actions via the Smart Executive. 4) Autonomous Navigation, which determines the spacecraft trajectory from,images of asteroids against the celestial sphere, and autonomously adjusts the trajectory to reach the target asteroid or comet. 5) Beacon Monitoring, which uses radio carrier modification and telemetry summarization to simplify ground monitoring of spacecraft health. Integration of these technologies into the spacecraft flight software architecture has presented a number of system engineering challenges, Some of these technologies were developed in a research-oriented, non-realtime, artificial intelligence organizational culture while spacecraft software is typically developed in a strong real-time, algorithmically-oriented culture. The Navigation technology has been developed in a ground-based environment. Integration of these different cultures and mutual education of the software team has been achieved. An early rapid prototype of an existing spacecraft design proved very valuable in educating the team members and in working out the development process. One way or another, these technologies represent the behaviors of spacecraft hardware and software, and their interaction with the outside world. Each technologies, as well software typically used in embedded systems, is suitable for modeling different aspects of these behaviors. Selection and coordination of the various aspects of these models represented in each of the software areas has required development of new system engineering techniques. The DS1 software development is being performed on a very tight schedule for spacecraft development (2.5 years from inception to launch.) In order to get an early start in the absence of a well-defined spacecraft design and mission requirements, a scenario-driven spiral development methodology was chosen, with frequent incremental software integrations. This process has also served to coordinate the efforts of the disparate teams involved and to provide frequent checks of the design. The methodology has required the development of processes and products significantly different from the waterfall lifecycle more typical in spacecraft software development. The different software languages and platforms used in implementing the various parts of the flight software have required the development of tools to ensure consistency of messages between software components. These tools are now being extended to the ground command system to ensure consistency and to provide early integration of the ground and flight software systems. RP Krasner, SM (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 409 EP 420 PG 12 WC Engineering, Aerospace SC Engineering GA BH30L UT WOS:A1997BH30L00024 ER PT B AU Holt, HM AF Holt, HM GP IEEE TI Assessment of fault-tolerant computing systems at NASA's Langley Research Center SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 2 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB In the early 1970's while NASA was studying Advanced Technology Transport concepts, researchers at NASA's Langley Research Center (LaRC) recognized that digital computer systems would be controlling civil transport aircraft in the near future and that the technology did not exist to determine if these digital systems would be reliable enough for this role. In addition, although several existing computer system concepts showed promise to meet the civil transport requirements, none had been realized in an operational system. Mr. Billy Dove, who led a branch at LaRC, developed a multi-initiative program to determine how to assess reliability and performance of fault-tolerant digital computer systems for determining if they could meet the requirements of a civil transport. Subsequent research emphasized the application of formal methods, system safety and digital upset. Some results indicated that dissimilar software may not be reliable enough for critical applications, testing alone will not prove the reliability of highly reliable digital systems and formal methods can find design errors missed by other assessment techniques. Future research will center around the application of formal mathematical methods, insuring software safety, and determination of digital system upsets due to electromagnetic radiation. The long term goal is to define methods for producing error-free systems for flight crucial civil transport applications. RP Holt, HM (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 150,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 541 EP 549 PG 9 WC Engineering, Aerospace SC Engineering GA BH30L UT WOS:A1997BH30L00032 ER PT B AU Imbriale, WA AF Imbriale, WA GP IEEE TI Design and applications of beam waveguide systems SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The various design techniques used for beam waveguide (BWG) feed systems are described. These include the use of Gaussian beam, Geometrical Optics, and Physical Optics design techniques for gain and efficiency and the waveguide modes theory for noise temperature determination. Examples illustrating the advantages, disadvantages and range of applicability of each design technique are given. Included are comparisons of computed and measured results. RP Imbriale, WA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 121 EP 134 PG 14 WC Engineering, Aerospace SC Engineering GA BH30M UT WOS:A1997BH30M00007 ER PT B AU Moran, AK LaBel, KA Seidleck, CM Marshall, P Barth, JM Marshall, C AF Moran, AK LaBel, KA Seidleck, CM Marshall, P Barth, JM Marshall, C GP IEEE TI In-flight analysis of enabling technology SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB Flight and ground test Single Event Effect (SEE) data are presented on spacecraft systems and experiments utilizing three enabling technologies, a Fiber Optic Data Bus (FODB), a Solid State Recorder (SSR), and a power metal oxide semiconductor field effect transistor (MOSFET). Extended datasets on system and device performance from multiple NASA spacecraft and experiments, as well as design implications of flight results, are discussed. RP Moran, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 735,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 333 EP 342 PG 10 WC Engineering, Aerospace SC Engineering GA BH30M UT WOS:A1997BH30M00021 ER PT B AU Caffrey, R Hestnes, P Cuviello, M Shaw, H AF Caffrey, R Hestnes, P Cuviello, M Shaw, H GP IEEE TI A standard spacecraft data system on a chip: NASA Goddard Space Flight Center's essential services node (ESN) SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB NASA Goddard Space Flight Center (GSFC), with the development of the Essential Services Node (ESN), has solved many of the common problems faced by spacecraft system designers. With each satellite and spacecraft developed, engineering teams repeatedly address several design requirements that are common to all projects as they pertain to the data system. Across different spacecraft on the system level, these recurring elements include size, weight, and power limitations, schedule and funding constraints, communication architecture design, subsystem integration, and documentation development and maintenance. Within any particular spacecraft at the subsystem level, various devices, such as the attitude control,systems, power systems, and scientific instruments, also share common design attributes. These include sensor interfacing, data processing, temperature and voltage monitoring, peripheral device control, and communication interfacing to other subsystems. In its effort to reduce the recurring engineering applied to these tasks, GSFC has developed the ESN. The ESN is a standard spacecraft data system in a single multi-chip module (MCM) package. The ESN is embedded into the subsystem of a spacecraft as a standardized means of performing the ''essential'' tasks of a data system. The ESN reduces the engineering effort required to meet the common requirements of a spacecraft's subsystem. This paper briefly describes the development history of the ESN and how previous work has led to its success. This paper also outlines the features, benefits, and applications of the ESN, as well as describing its design in detail and presenting some of the ESN's applications. RP Caffrey, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 970-2,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 505 EP 521 PG 17 WC Engineering, Aerospace SC Engineering GA BH30M UT WOS:A1997BH30M00033 ER PT B AU Mysoor, NR Kayalar, S Lane, JP Kermode, AW AF Mysoor, NR Kayalar, S Lane, JP Kermode, AW GP IEEE TI Performance of a Ka-band transponder breadboard for deep space applications SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This article summarizes the design concepts and implementation of an advanced Ka-band (34.4GHz/32GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2GHz / 8.4GHz) deep space transponder (DST) to provide Ka-band up/Ka- and X-band down capability. In addition, it can also be configured to provide X-band up/Ka- and X-band down. The Ka-band transponder breadboard incorporates several state-of-the-art components including sampling mixers, Ma-band dielectric resonator oscillator, and microwave monolithic integrated circuits (MMICs). The MMICs that were tested in the breadboard include upconverters, downconverters, automatic gain control circuits, mixers, phase modulators, and amplifiers. The measured receiver dynamic range, tracking range, acquisition rate, static phase error, and phase jitter characteristics of the Ma-band breadboard interfaced to the advanced engineering model X-band DST are in good agreement with the expected performance. The results show a receiver tracking threshold of -149dBm with a dynamic range of 80dB, and a downlink phase jitter of 7 degrees rms. The analytical results of phase noise and Allan standard deviation are in good agreement with the experimental results. RP Mysoor, NR (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 547 EP 557 PG 11 WC Engineering, Aerospace SC Engineering GA BH30M UT WOS:A1997BH30M00036 ER PT B AU Morakis, JC Miller, WH AF Morakis, JC Miller, WH GP IEEE TI Coding techniques under study at NASA SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 3 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB NASA is studying coding techniques in an effort to achieve communications from spacecraft at lower effective isotropic radiated power. Presently NASA's coding standards support a (2,1,6) convolutional inner code and a Reed-Solomon (255,223,8) outer code; during the past two years studies were conducted on the performance of a long constraint length (2,1,14) convolutional code and the Turbo codes. Flight experiments will lead to results on the actual performance, complexity and implementation of such coding systems. RP Morakis, JC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 559 EP 565 PG 7 WC Engineering, Aerospace SC Engineering GA BH30M UT WOS:A1997BH30M00037 ER PT B AU Trout, DH Audeh, NF AF Trout, DH Audeh, NF GP IEEE TI Evaluation of electromagnetic radiated susceptibility testing using induced currents SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This paper uses electromagnetic field theory to examine the relations between radiated induced currents and Bulk Current Injection (BCI) injected currents to compare the data from the BCI and radiated field induced currents and to determine the range where BCI effectively simulates the radiated induced coupling. Establishing a uniform plane wave to illuminate the cables is also addressed. The test includes illuminating a wire bundle with a uniform plane wave and comparing the current induced on individual wires with the current induced in the same wire by the BCI technique. The uniform plane waves are generated by a parallel plate guide. The loads are varied on the wires to examine the effects of the load on field to wire coupling versus BCI method. The effects of BCI on inner conductors of shielded cables is also addressed. RP Trout, DH (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 69 EP 80 PG 12 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00005 ER PT B AU Dallas, SS AF Dallas, SS GP IEEE TI Mars Global Surveyor mission SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The Mars Global Surveyor (MGS) Spacecraft was successfully launched on November 7, 1996 to the planet Mars for an extended study of the planet's surface, atmosphere, gravitational field and magnetic field. In order to achieve the scientific objectives of the mission, the spacecraft will be inserted into a low-altitude, near-polar, sun-synchronous orbit. Data will be collected and returned from six prime experiments on the spacecraft for over one Martian year (687 Earth days) and will provide for a better understanding of the geology, geophysics, and climatology of Mars. RP Dallas, SS (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 173 EP 189 PG 17 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00014 ER PT B AU Muirhead, BK AF Muirhead, BK GP IEEE TI Mars Pathfinder flight system integration and test SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB This paper describes the system integration and test experiences, problems and lessons learned during the assembly, test and launch operations (ATLO) phase of the Mars Pathfinder flight system scheduled to land on the surface of Mars on July 4, 1997. Mars Pathfinder is one of the new series of small, challenging missions doing significant science/engineering on a fast schedule and cost capped budget. Pathfinder follows in the footsteps and goes beyond the very successful Viking mission of 1976. RP Muirhead, BK (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 191 EP 205 PG 15 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00015 ER PT B AU Atkins, KL Brownlee, DE Duxbury, T Yen, CW Tsou, P Vellinga, JM AF Atkins, KL Brownlee, DE Duxbury, T Yen, CW Tsou, P Vellinga, JM GP IEEE TI STARDUST: Discovery's interstellar dust and cometary sample return mission SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB The STARDUST Discovery mission will collect samples of cometary coma and interstellar dust and return them to Earth. Five years after launch in February 1999, coma dust will be captured by impact into ultra-low-density silica aerogel during a 6 km/s flyby of Comet Wild 2. The returned samples will be investigated at laboratories where the most critical information on these primitive materials is retained. The Jet Propulsion Laboratory provides project management with Lockheed Martin Astronautics as the spacecraft industrial partner. STARDUST management is aggressively pursuing cost control through the use of Total Quality Management principles, specifically operating in a Project Engineering and Integration Team that ''flattens'' the traditional hierarchical structure by including all project elements from the beginning, in a concurrent engineering framework focusing on evolving Integrated Mission Capability. RP Atkins, KL (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91011, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 229 EP 245 PG 17 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00017 ER PT B AU Neal, RD AF Neal, RD GP IEEE TI Modeling the object-oriented space through validated measures SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB In order to Software and the software process, software measurement must be better understood. A beginning step toward a better understanding of software measurement is the categorization of the measurements by some meaningful taxonomy. The most meaningful taxonomy would capture the basic nature of the object-oriented (O-O) space. interesting characteristics of object-oriented software offer a starting point for such a categorization of measures. A taxonomy has been developed based upon characteristics of object-oriented gathered fi om the literature. This taxonomy allows us to easily see gaps and redundancies in the O-O measures. The taxonomy also clearly differentiates among taxa so that there is no ambiguity as to the taxon to which a measure belongs. The taxonomy has been populated with thirty-two measures that have been validated in the narrow sense of Fenton [9] using measurement theory with Zuse's [30] augmentation. RP Neal, RD (reprint author), W VIRGINIA UNIV,NASA,SOFTWARE RES LAB,100 UNIV DR,FAIRMONT,WV 26554, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 315 EP 327 PG 13 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00025 ER PT B AU Fukunaga, AS Chien, S Mutz, D Sherwood, RL Stechert, AD AF Fukunaga, AS Chien, S Mutz, D Sherwood, RL Stechert, AD GP IEEE TI Automating the process of optimization in spacecraft design SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB Spacecraft design optimization is, difficult problem, due to the complexity of optimization cost surfaces and the human expertise in optimization that is necessary in order to achieve good results. In this paper, we propose the use of a Set of generic, metaheuristic optimization algorithms (e.g., genetic algorithms, simulated annealing), which is configured for a particular optimization problem by an adaptive problem solver based on artificial intelligence and machine learning techniques, We describe work in progress on OASIS, a system for adaptive problem solving based on these principles. RP Fukunaga, AS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 525-3660,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 411 EP 427 PG 17 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00031 ER PT B AU Webb, E Cunningham, M Leath, TT AF Webb, E Cunningham, M Leath, TT GP IEEE TI The WARP: Wideband advanced recorder processor for the new millennium program EO-1 SO 1997 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOL 4 LA English DT Proceedings Paper CT 1997 IEEE Aerospace Conference CY FEB 01-08, 1997 CL ASPEN, CO SP IEEE Aerosp & Electr Syst Soc AB NASA's New Millennium Program (NMP) will Sponsor a series of small scientific spacecraft whose purpose is to demonstrate new technologies and methods of spacecraft design by using unique teaming arrangements between government and industry. EO-l,the first Earth Orbiter satellite in the NMP, will perform the Advanced Land Imager (ALI) mission. The ALI, combined with other instruments aboard EO-1, will output nearly 1 Gigabit per second of raw science data. An innovative data system, the Wideband Advanced Recorder Processor (WARP), is being developed to handle these very high data Ingest rates. In keeping with the philosophy of the EO-1 mission, the WARP will use ''best commercial practices'' in its design guidelines. The WARP will feature extensive use of new technology including the Spaceborne Fiber Optic Data Bus (SFODB), Chip-on-Board surface mounted memory components, and stacked multi-die wafer segments of Dynamic RAM. The WARP implements a scalable architecture that can be applied to future missions requiring a Solid State Recorder (SSR) and a high performance science data processor. The WARP represents a significant advance over previous spaceflight SSRs. This paper will describe the WARP and its capabilities. RP Webb, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,FLIGHT HARDWARE TECHNOL GRP,CODE 735 FLIGHT DATA SYST,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3742-5 PY 1997 BP 471 EP 488 PG 18 WC Engineering, Aerospace SC Engineering GA BH30N UT WOS:A1997BH30N00036 ER PT B AU Buehler, MG Cheng, LJ Martin, DP AF Buehler, MG Cheng, LJ Martin, DP GP IEEE TI Test structures applied to the rapid prototyping of sensors SO 1997 IEEE INTERNATIONAL CONFERENCE ON MICROELECTRONIC TEST STRUCTURES - PROCEEDINGS LA English DT Proceedings Paper CT 1997 IEEE International Conference on Microelectronic Test Structures CY MAR 17-20, 1997 CL MONTEREY, CA SP IEEE Electron Devices Soc AB A multi-project ceramic substrate was used in developing a gas sensor and pressure sensor. The co-fired ceramic substrate contained 36 chips with six variants including sensors, process control monitors, and an interconnect chip. The gas sensor is being developed as an air quality monitor for the Space Shuttle and the pressure gauge as a Martian barometer. This effort is in its initial phase. The test structures were used to identify problems and to point to solutions. RP Buehler, MG (reprint author), CALTECH,JET PROP LAB,MICRODEVICES LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-3244-X PY 1997 BP 212 EP 218 DI 10.1109/ICMTS.1997.589406 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing SC Engineering; Materials Science GA BH73B UT WOS:A1997BH73B00044 ER PT B AU Baram, Y AF Baram, Y GP IEEE TI Soft nearest neighbor classification SO 1997 IEEE INTERNATIONAL CONFERENCE ON NEURAL NETWORKS, VOLS 1-4 LA English DT Proceedings Paper CT 1997 IEEE International Conference on Neural Networks (ICNN 97) CY JUN 09-12, 1997 CL HOUSTON, TX SP IEEE, Neural Networks Council AB It is shown how soft classification, which allows for the creation of indecision domains near given separation surfaces between two classes, applies to the nearest neighbor method, and how the optimal size of the indecision domain can be found from the training data. The performance of the soft nearest neighbor classifier is compared to that of the conventional classifier using stock trading data. C1 TECHNION ISRAEL INST TECHNOL,DEPT COMP SCI,IL-32000 HAIFA,ISRAEL. RP Baram, Y (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4123-6 PY 1997 BP 1469 EP 1473 PG 5 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BJ42Y UT WOS:A1997BJ42Y00280 ER PT S AU Lee, S Ahn, SC Meyyappan, A AF Lee, S Ahn, SC Meyyappan, A GP IEEE TI Depth from magnification and blurring SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB A new method of constructing 3D maps based on the relative magnification and blurring of a pair of images is presented, where the images are taken at two camera positions of a small displacement. The method, referred to here as ''Depth from Magnification and Blurring,'' aims at generating a precise 3D map of local scenes or objects to be manipulated by a robot arm with a hand-eye camera. The method uses a single standard camera with telecentric lens, and assumes neither active illumination nor active control of camera parameters. The proposed depth extraction algorithm is simple in computation. Fusing the two disparate sources of depth information, magnification and blurring, the proposed method provides more accurate and robust depth estimation. Experimental results demonstrate the effectiveness of the proposed method. RP Lee, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 137 EP 142 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00022 ER PT S AU Backes, PG BarCohen, Y Joffe, B AF Backes, PG BarCohen, Y Joffe, B GP IEEE TI The Multifunction Automated Crawling System (MACS) SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB A new robotic crawler is being developed for inspection of large aircraft external surfaces. The Multifunction Automated Crawling System (MA CS) has been designed and fabricated to carry miniature instrumentation to perform a wide variety of tasks while being attached to an aircraft's surface. The immediate application of MACS is inspection of the exterior of large military aircraft such as the C-5. Various inspection payload modules could be incorporated onto the MACS crawler to perform the desired inspections. MACS employs ultrasonic motors for mobility and suction cups for surface adherence. MACS has two legs for linear motion and a rotation element for turning, enabling any simultaneous combination of motion from linear to rotation about a central axis. RP Backes, PG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 23 Z9 23 U1 1 U2 3 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 335 EP 340 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00054 ER PT S AU Backes, PG Tharp, GK Tso, KS AF Backes, PG Tharp, GK Tso, KS GP IEEE TI The Web Interface for Telescience (WITS) SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB The Web Interface for Telescience (WITS) has been developed to enable scientists to participate in planetary rover missions from their home institutions, rather than having to travel to JPL as has been required in the past. A scientist accesses WITS via a commercial web browser. WITS provides various views of the scene including a descent image view which allows the user to see where the rover has been and currently is in a global perspective, a panoramic view which is an over-head view of the area immediately around the rover, and a wedge view which is an image from a rover-mounted camera. Scientists can select science targets in a wedge image and science subtasks to perform at those targets. A mission planner can select rover waypoints to traverse between science targets, and waypoint subtasks to perform at those locations. A public version allows the general public to view the same information and plan their own simulated missions. RP Backes, PG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 13 Z9 15 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 411 EP 417 PG 7 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00066 ER PT S AU Seraji, H Bon, B Steele, R AF Seraji, H Bon, B Steele, R GP IEEE TI Experiments in real-time collision avoidance for dexterous 7-DOF arms SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB The paper presents experimental results that demonstrate a new approach to real-time collision avoidance for 7-DOF arms. The collision avoidance problem is formulated and solved as a force control problem. Virtual forces opposing intrusion of the arm into the obstacle safety zone are computed in real time. These forces are then nullified by employing an outer feedback loop which perturbs the arm Cartesian commands for the inner position control system. The approach is implemented and tested on a 7-DOF RRC arm and a set of experiments are conducted in the laboratory. These experiments demonstrate perturbations of the end-effector position and orientation, as well as the arm configuration, in order to avoid impending collisions. The approach is simple, computationally fast, requires minimal modification to the arm control system, and applies to whole-arm collision avoidance. RP Seraji, H (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 569 EP 574 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00091 ER PT S AU Tunstel, E Danny, H Lippincott, T Jamshidi, M AF Tunstel, E Danny, H Lippincott, T Jamshidi, M GP IEEE TI Adaptive fuzzy-behavior hierarchy for autonomous navigation SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB Adaptive behavioral capabilities are necessary for robust navigation in. non-engineered environments. A control approach to adaptive behavior is described which exploits the approximate reasoning facility of fuzzy logic. In particular, a behavior-based architecture for hierarchical fuzzy control of mobile robots is presented. Its structure is described as well as mechanisms of control decision-making which give rise to adaptive behavior. Control decisions result from a consensus of recommendations offered only by behaviors that are applicable to current situations. Indoor navigation examples demonstrate the practicality of the approach and reveals characteristics of multiple behavior interaction. RP Tunstel, E (reprint author), UNIV NEW MEXICO,DEPT ELECT & COMP ENGN,NASA,CTR AUTONOMOUS CONTROL ENGN,ALBUQUERQUE,NM 87131, USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 829 EP 834 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00131 ER PT S AU Matthies, L Balch, T Wilcox, B AF Matthies, L Balch, T Wilcox, B GP IEEE TI Fast optical hazard detection for planetary rovers using multiple spot laser triangulation SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB A new laser-based optical sensor system that provides hazard detection for planetary revers is presented. The sensor can support safe travel at speeds up to 12cm/second for large (Im) revers in full sunlight on Earth or Mars. This is at least a 5 times improvement over the sensor aboard NASA's Mars Pathfinder rover. The system overcomes limitations in the older design that require image differencing to detect a laser stripe in full sun. The new system ensures the projected laser light is detectable in a single image, eliminating the requirement for additional difference images. The improvement is significant since any reduction in image gathering or processing time provides for faster rover motion. The savings are even more important in the case of a Mars rover since power and radiation-hardening requirements lead to severely constrained computational resources. The paper includes a thorough discussion of design details and tradeoffs for optical hazard sensing that will benefit future efforts in this area. RP Matthies, L (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 5 Z9 6 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 859 EP 866 PG 8 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00136 ER PT S AU Lee, S Yi, C AF Lee, S Yi, C GP IEEE TI Tolerance analysis for multi-chain assemblies with sequence and functionality constraints SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB In this paper, we present a novel approach for evaluating the assemblability of a product based on tolerances and adjustable displacements. An adjustable displacement is a functionally permitted free space between two mating features, which can be used for compensating tolerances. The assemblability of a product is computed in term of a multi chain by incrementally solving the parallel chains. We consider both the functionality and assembly sequence constraint in the evaluation. The result of the computation is a statistical measure of the product assemblability which can be used by the designer to evaluate and to optimize the tolerance allocation. In addition, this measure can be used for evaluating assembly sequences. The algorithms and simulation results are given. RP Lee, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 927 EP 932 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00146 ER PT S AU Kumbla, KK Jamshidi, M AF Kumbla, KK Jamshidi, M GP IEEE TI Neural network based identification of robot dynamics used for neuro-fuzzy controller SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc DE system identification; self organizing fuzzy controller; neural networks; neurofuzzy controller; robotics AB A technique of identifying the dynamics of a robotics system using neural network is presented, The identified model is used by a fuzzy controller to evaluate the range of the control variables and also the performance of the adaptive control lams on the identified modal, An overview of the neuro-fuzzy control architecture is also discussed, This architecture uses two neural networks, one which identifies the system dynamics and another classifies the temporal response of the robotic system. The information from the neural networks is used to make suitable adjustment is made in the parameter of the fuzzy controller. This paper however concentrates on the theory and operation of identifying the dynamics of a Adept-Two industrial robot. Simulation results are presented. RP Kumbla, KK (reprint author), UNIV NEW MEXICO,NASA,CTR AUTONOMOUS CONTROL ENGN,DEPT ELECT & COMP ENGN,ALBUQUERQUE,NM 87131, USA. NR 0 TC 4 Z9 5 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 1118 EP 1123 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00177 ER PT S AU Akbarzadeh, MR Jamshidi, M Kim, YT AF Akbarzadeh, MR Jamshidi, M Kim, YT GP IEEE TI Evolutionary fuzzy control of a flexible-link SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB In recent years, evolution-based knowledge optimization has gained a great deal of popularity due to its inherent ability in efficient and parallel search of complex and multi-modal landscapes, Application of Genetic Algorithms (GA) to knowledge enhancement involves several aspects, First is how to code a string to represent all the necessary degrees of freedom for search in the fuzzy knowledge domain. The second aspect is how to incorporate existing expert knowledge into the GA-optimizing algorithm. And in general, how to take advantage of several experts' opinions in creation of an initial population. Conventional applications of GA-Fuzzy suggest using a random initial population. However, it is intuitively clear that any search routine could converge faster if starting points are good solutions. In this paper, a methodology is illustrated which incorporates expert knowledge in creating an initial population while allowing for randomness among members of the population for diversity. Furthermore, the methodology is applied to step response optimisation of a flexible-link feedback control system. RP Akbarzadeh, MR (reprint author), UNIV NEW MEXICO,NASA,CTR AUTONOMOUS CONTROL ENGN,ELECT ENGN & COMP ENGN BLDG,ALBUQUERQUE,NM 87131, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 1124 EP 1129 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00178 ER PT S AU Fiorini, P Ali, K Seraji, H AF Fiorini, P Ali, K Seraji, H GP IEEE TI Health care robotics: A progress report SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB This paper describes the approach followed in the design of a service robot for health care applications. Under the auspices of the NASA Technology Transfer Program, a partnership was established between JPL and RWI, a manufacturer of mobile robots, to design and evaluate a mobile robot for health care assistance to the elderly and the handicapped. The activities of the first phase of the project include the development of a multi-modal operator interface, and the design and fabrication of a manipulator arm for the mobile robot. This paper describes the architecture of the system, the features of the manipulator arm, and the operator interface. RP Fiorini, P (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 1271 EP 1276 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00201 ER PT S AU Kim, WS Gennery, DB Chalfant, EC AF Kim, WS Gennery, DB Chalfant, EC GP IEEE TI Computer vision assisted semi-automatic virtual reality calibration SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB New developments of edge matching based semiautomatic virtual reality calibration are presented to provide more reliable and accurate telerobotic servicing. Three basic algorithms employed are 1) weighted average local edge detector, 2) weighted least squares for the edge-based camera calibration and object localization, and 3) robust matching to remove outliers. A key new 20-variable least-squares algorithm is developed that updates both the camera and the object models simultaneously for given two camera views of two mating objects. This simultaneous update reduces relative positioning errors considerably, and is essential to achieve high alignment precision. The developed system has been successfully tested for an ORU (Orbital Replacement Unit) insertion task within a +/-1/4 inch and +/-3 degrees alignment precision. RP Kim, WS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 1335 EP 1340 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00211 ER PT S AU Bon, B Seraji, H AF Bon, B Seraji, H GP IEEE TI Real-time model-based obstacle detection for the NASA Ranger Telerobot SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB This paper describes Me approach and algorithms developed far real-time model-based obstacle detection and distance computation for the NASA Ranger Telerobotic Flight Experiment. Objects of interest, such as manipulator arms or the Ranger vehicle and solar arrays, are modelled using a small set of component types: edges, polygonal faces and cylindrical links. Link positions are computed using standard forward kinematics, and distances between object components are computed directly using equations derived from geometry. Prioritized lists of potential obstacles for each manipulator link eliminate needless distance computations and assure that the mast likely obstacles are checked, even if the computation is terminated early due to real-time constraints. A test program, utilizing a 3-D graphical simulation and providing a graphical user interface for operator control, has been developed and used to test and demonstrate obstacle detection. An earlier paper [1] described how the obstacle detection results are utilized for collision avoidance. RP Bon, B (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 5 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 1580 EP 1587 PG 8 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00251 ER PT S AU Lee, SH Ro, SW AF Lee, SH Ro, SW GP IEEE TI Uncertainty self-management with perception net based geometric data fusion SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB The capability of robotic systems to deal with uncertainties, biases, and errors automatically is crucial for the tasks defined in an unstructured environment. In this paper, we present a method of automatically reducing uncertainties and calibrating possible biases involved in sensed data and extracted features by a system based on the geometric data fusion. The perception net, as a structural representation of the sensing capabilities of a system, connects features of various levels of abstraction, referred to here as logical sensors, with their functional relationships such as feature transformations, data fusions, and constraints to be satisfied. The net maintains the consistency of logical sensors based on the forward propagation of uncertainties as well as the backward propagation of constraint errors. A novel geometric data fusion algorithm is presented as a unified framework for computing forward and backward propagations through which the net achieves the self-reduction of uncertainties and self-identification of biases. The effectiveness of the proposed method is validated through simulation by applying it to a mobile robot self-localization problem. RP Lee, SH (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 2075 EP 2081 PG 7 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00330 ER PT S AU Hayati, S Volpe, R Backes, P Balaram, J Welch, R AF Hayati, S Volpe, R Backes, P Balaram, J Welch, R GP IEEE TI The Rocky 7 rover: A Mars sciencecraft prototype SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB This paper describes the design implementation at the Jet Propulsion Laboratory of a small rover for future Mars missions requiring long traverses and rover-based science experiments, The small rover prototype, called Rocky 7, is capable of long traverses, autonomous navigation, and science instrument control. This rover carries three science instruments, and can be commanded from any computer platform from any location using the World Wide Web. Hn this paper we describe the mobility system, the sampling system, the sensor suite, navigation and control, onboard science instruments, and the ground command and control system, We also present key accomplishments of a recent field test of Rocky 7 in the Mojave Desert in California. RP Hayati, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 41 Z9 49 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 2458 EP 2464 PG 7 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00390 ER PT S AU Bonitz, RG AF Bonitz, RG GP IEEE TI Mars surveyor '98 lander MVACS robotic arm control system design concepts SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc DE control; manipulator; Mars; robot; trajectory; 4-DOF AB This paper describes the control system design concepts for the Mars Volatiles and Climate Surveyor (MVACS) Robotic Arm which supports the scientific investigations to be conducted as part of the Mars Surveyor '98 Lander project. Novel solutions are presented to some of the unique problems encountered in this demanding space application with its tight constraints on mass, power, volume, and computing resources. Problems addressed include the 4-DOF forward and inverse kinematics, trajectory planning to minimize potential impact damage, joint drive train protection, Lander tilt prevention, hardware fault monitoring, and collision avoidance. RP Bonitz, RG (reprint author), CALTECH,JET PROP LAB,TELEROBOT RES & APPLICAT GRP,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 2465 EP 2470 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00391 ER PT S AU LaiFook, KM Ambrose, RO AF LaiFook, KM Ambrose, RO GP IEEE TI Automation of bioregenerative habitats for space environments SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB Long duration manned missions to explore new environments require habitats with automated bioregenerative life support systems, since resupply from Earth is not feasible. Bioplex, the ground facility proposed by NASA Johnson Space Center for bioregenerative life support research, consists of cylindrical modules including biomass chambers that provide food and oxygen to support crew survival. Manual duties involved in processing and maintaining crops consume more calories that the crops can reasonably produce. Decreasing risk in the hazardous environment of distant closed systems, automation of crop tasks saves time and energy, reduces crew exposure to mold and exposed harvesting machinery, and improves efficiency. Automation needs are many in Bioplex but heavy hauling and lifting comsume a substantial amount of calories, since the corridors in the chamber are narrow and cramped. Various configurations of a tray handling system, Traybot, were explored, resulting in an overhead two-rail system with a vertically driven basket. Modes of operation for harvest cycles determined the requirements for the chassis, basket, power, actuator, and control components. In a hazardous environment, working along side humans demanded flexibility in design and control of Traybot. The Bioplex study found that Traybot's role is crucial to survival in space habitats. RP LaiFook, KM (reprint author), NASA,JOHNSON SPACE CTR,MAIL CODE ER4,HOUSTON,TX 77059, USA. RI Cody, Kristin/G-2709-2015 NR 0 TC 1 Z9 1 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 2471 EP 2476 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00392 ER PT S AU Chien, SA Hill, RW Govindjee, A Wang, X Estlin, T Griesel, MA Lam, R Fayyad, KV AF Chien, SA Hill, RW Govindjee, A Wang, X Estlin, T Griesel, MA Lam, R Fayyad, KV GP IEEE TI A hierarchical architecture for resource allocation, plan execution, and revision for operation of a network of communications antennas SO 1997 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION - PROCEEDINGS, VOLS 1-4 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Conference on Robotics and Automation (ICRA97) - Teaming to Make an Impact CY APR 20-25, 1997 CL ALBUQUERQUE, NM SP IEEE, Robot & Automat Soc AB This paper describes a hierarchical scheduling, planning, control, and execution monitoring architecture for automating operations of a worldwide network of communications antennas. We describe the network automation problem and current mode of operations. We then describe a three layer hierarchical architecture for automating network operations. In particular we describe the notion of plan/schedule generation, execution, and revision at each level. Finally, we describe the current state of deployment for each segment of the automation architecture. RP Chien, SA (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 1050-4729 BN 0-7803-3613-5 J9 IEEE INT CONF ROBOT PY 1997 BP 3340 EP 3347 PG 8 WC Automation & Control Systems SC Automation & Control Systems GA BJ42X UT WOS:A1997BJ42X00531 ER PT B AU Tunstel, E Danny, H Lippincott, T Jamshidi, M AF Tunstel, E Danny, H Lippincott, T Jamshidi, M GP IEEE TI Autonomous navigation using an adaptive hierarchy of multiple fuzzy-behaviors SO 1997 IEEE INTERNATIONAL SYMPOSIUM ON COMPUTATIONAL INTELLIGENCE IN ROBOTICS AND AUTOMATION - CIRA '97, PROCEEDINGS: TOWARDS NEW COMPUTATIONAL PRINCIPLES FOR ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Symposium on Computational Intelligence in Robotics and Automation (CIRA 97) - Towards New Computational Principles for Robotics and Automation CY JUL 10-11, 1997 CL MONTEREY, CA SP IEEE Robot & Automat Soc, IEEE Neural Network Council AB Adaptive behavioral capabilities are necessary for robust mobile robot navigation in non-engineered environments. Robust behavior requires that uncertainty be accommodated in the robot control system, especially when autonomy is desired. Fuzzy logic control technology enables development of controllers which can provide the necessary computational intelligence in real-time. This paper presents the incorporation of fuzzy logic, into the framework of behavior-based control. An architecture for hierarchical behavior control is presented in which control decisions result from a consensus of behavioral recommendations. Multiple fuzzy-behavior coordination is discussed and applied to autonomous navigation without explicit maps. Performance and robustness is demonstrated by implementation on a mobile robot with significant mechanical imperfections. RP Tunstel, E (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8138-1 PY 1997 BP 276 EP 281 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA BJ29M UT WOS:A1997BJ29M00043 ER PT B AU AkbarzadehT, MR Jamshidi, M AF AkbarzadehT, MR Jamshidi, M GP IEEE TI Incorporating A-priori expert knowledge in genetic algorithms SO 1997 IEEE INTERNATIONAL SYMPOSIUM ON COMPUTATIONAL INTELLIGENCE IN ROBOTICS AND AUTOMATION - CIRA '97, PROCEEDINGS: TOWARDS NEW COMPUTATIONAL PRINCIPLES FOR ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Symposium on Computational Intelligence in Robotics and Automation (CIRA 97) - Towards New Computational Principles for Robotics and Automation CY JUL 10-11, 1997 CL MONTEREY, CA SP IEEE Robot & Automat Soc, IEEE Neural Network Council AB Conventional applications of GA suggest using a random initial population. However, it is intuitively clear that any search routine could converge faster if starting points are good solutions. In this paper, a novel method is illustrated which incorporates a-priori knowledge in creating a fitter initial population while allowing for randomness among members of the population for diversity. Furthermore, the methodology is applied to optimization of a fuzzy controller's membership parameters in a water desalination control process, in particular a brine heater temperature control problem. It is shown that the GA-improved PID fuzzy controller is able to reduce overshoot by 80 percent when compared to non-GA PID fuzzy controller. RP AkbarzadehT, MR (reprint author), UNIV NEW MEXICO,NASA,CTR AUTONOMOUS CONTROL ENGN,EECE BLDG,ROOM 110,ALBUQUERQUE,NM 87131, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8138-1 PY 1997 BP 300 EP 305 DI 10.1109/CIRA.1997.613872 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA BJ29M UT WOS:A1997BJ29M00047 ER PT B AU Padgett, C Woodward, G AF Padgett, C Woodward, G GP IEEE TI A hierarchical, automated target recognition algorithm for a parallel analog processor SO 1997 IEEE INTERNATIONAL SYMPOSIUM ON COMPUTATIONAL INTELLIGENCE IN ROBOTICS AND AUTOMATION - CIRA '97, PROCEEDINGS: TOWARDS NEW COMPUTATIONAL PRINCIPLES FOR ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 1997 IEEE International Symposium on Computational Intelligence in Robotics and Automation (CIRA 97) - Towards New Computational Principles for Robotics and Automation CY JUL 10-11, 1997 CL MONTEREY, CA SP IEEE Robot & Automat Soc, IEEE Neural Network Council AB A hierarchical approach is described for an automated target recognition (ATR) system. VIGILANTE, that uses a massively parallel, analog processor (3DANN). The 3DANN processor is capable of performing 64 concurrent inner products of size 1x4096 every 250 nanoseconds. A complete 64x64 raster scan of a 256x256 image can be evaluated by the 3DANN with its 64 modifiable templates in about 16 milliseconds. To fully utilize the analog processor and accommodate its high bandwidth capabilities, the vectors (templates) loaded on the 3DANN perform dimensionality reduction for a backend set of classifiers. The templates used in this ATR algorithm are hierarchically generated sets of eigenvectors taken from a partitioned set of library object images. As information is accumulated about the target (e.g. object class), a more refined set of eigenvectors reflecting this knowledge can be loaded and more specialized classifiers utilized. The classifiers provide information related to the ATR task: location, class, sub-class, and orientation of target(s). We report some preliminary results that examine the performance of orientation classifiers. With no knowledge about object class or orientation, a neural network achieves 94.2% in determining to which one of three classes from vertical (30 degrees, 15 degrees, or 60 degrees) an object image is oriented (+/-30 degrees). Using an eigenvector template set generated from a distribution where both object class and orientation are known, a neural network classifier achieves 96% in orienting the object to within +/-22.5 degrees. This information can be used to load even more specific eigenvector sets which should lead to more accurate object location during tracking and an enhancement in object recognition tasks. RP Padgett, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-8138-1 PY 1997 BP 374 EP 379 DI 10.1109/CIRA.1997.613884 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA BJ29M UT WOS:A1997BJ29M00058 ER PT S AU Ponchak, GE Katehi, LPB AF Ponchak, GE Katehi, LPB BE Koepf, GA Jelks, C Huebner, D Donovan, JJ TI Characteristics of finite ground coplanar waveguide lumped elements SO 1997 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS I-III: HIGH FREQUENCIES IN HIGH PLACES SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT 41st Annual IEEE MTT-Society International Microwave Symposium (IMS) at 1997 Microwave Week CY JUN 08-13, 1997 CL DENVER, CO SP IEEE MTT Soc AB This paper presents the measured characteristics of lumped elements in coplanar waveguide with narrow width ground planes. It is shown for the first time that lumped elements may be placed in the ground planes of the Finite Ground Coplanar waveguide (FGC) to obtain enhanced electrical characteristics. RP Ponchak, GE (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,MS 54-5,CLEVELAND,OH 44135, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-645X BN 0-7803-3814-6 J9 IEEE MTT-S PY 1997 BP 1003 EP 1006 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BH95V UT WOS:A1997BH95V00235 ER PT B AU Nichols, DK Coss, JR Miyahira, TF Schwartz, HR Swift, GM Koga, R Crain, WR Crawford, KB Penzin, SH AF Nichols, DK Coss, JR Miyahira, TF Schwartz, HR Swift, GM Koga, R Crain, WR Crawford, KB Penzin, SH GP IEEE TI Device SEE susceptibility from heavy ions (1995-1996) SO 1997 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1997 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 24, 1997 CL SNOWMASS VILLAGE, CO SP IEEE Nuclear & Plasma Sci Soc, IEEE AB A seventh set of heavy ion single event effects (SEE) test data have been collected since the last IEEE publications. SEE trends are indicated for several functional classes of ICs. RP Nichols, DK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4061-2 PY 1997 BP 1 EP 13 DI 10.1109/REDW.1997.629790 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BK02A UT WOS:A1997BK02A00001 ER PT B AU LaBel, KA Moran, AK Seidleck, CM Stassinopoulos, EG Barth, JM Marshall, P Carts, M Marshall, C Kinnison, J AF LaBel, KA Moran, AK Seidleck, CM Stassinopoulos, EG Barth, JM Marshall, P Carts, M Marshall, C Kinnison, J GP IEEE TI Single event effect test results for candidate spacecraft electronics SO 1997 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1997 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 24, 1997 CL SNOWMASS VILLAGE, CO SP IEEE Nuclear & Plasma Sci Soc, IEEE AB We present both heavy ion and proton single event effect (SEE) ground test results for candidate spacecraft electronics. A variety of digital, analog, and fiber optic devices were tested, including DRAMs, FPGAs and fiber links. RP LaBel, KA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 735-1,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4061-2 PY 1997 BP 14 EP 21 DI 10.1109/REDW.1997.629791 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BK02A UT WOS:A1997BK02A00002 ER PT B AU Kouba, CK Choi, G AF Kouba, CK Choi, G GP IEEE TI The single event upset characteristics of the 486-DX4 microprocessor SO 1997 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1997 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 24, 1997 CL SNOWMASS VILLAGE, CO SP IEEE Nuclear & Plasma Sci Soc, IEEE AB This research describes the development of an experimental radiation testing environment to investigate the single event effect (SEE) susceptibility of the 486-DX4 microprocessor. The goal of this work was to experimentally characterize the single event effects of the 486-DX4 microprocessor using a cyclotron facility as the fault-injection source. Three different heavy ions were used to provide different linear energy transfer rates, and a total of six microprocessor parts were tested from two different commercial vendors. A consistent set of error modes were identified and the upset cross-sections were calculated. Results show a distinct difference in on-chip cache susceptibility, as well as a marked difference in vendor performance. RP Kouba, CK (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,AVION SYST DIV,EV211,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4061-2 PY 1997 BP 48 EP 52 DI 10.1109/REDW.1997.629797 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BK02A UT WOS:A1997BK02A00008 ER PT B AU Sharma, AK Sahu, K AF Sharma, AK Sahu, K GP IEEE TI Characterization of commercial high density memories under low dose rate total ionizing dose (TID) testing for NASA programs SO 1997 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1997 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 24, 1997 CL SNOWMASS VILLAGE, CO SP IEEE Nuclear & Plasma Sci Soc, IEEE AB This paper reports the results of low dose rate (0.04-0.08 rads (Si)/sec) total ionizing dose (TID) tests performed on different types of commercial high density memories. The parts used in this evaluation, represented memory technologies such as DRAMs, SRAMs, EEPROMs and Flash memories in 5V and/or 3.3V versions from various manufacturers of plastic and ceramic packages. RP Sharma, AK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4061-2 PY 1997 BP 90 EP 96 DI 10.1109/REDW.1997.629804 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BK02A UT WOS:A1997BK02A00015 ER PT B AU Lee, CI Nguyen, DN Johnston, AH AF Lee, CI Nguyen, DN Johnston, AH GP IEEE TI Total ionizing dose effects on 64Mb 3.3V DRAMs SO 1997 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT 1997 IEEE Radiation Effects Data Workshop / IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 24, 1997 CL SNOWMASS VILLAGE, CO SP IEEE Nuclear & Plasma Sci Soc, IEEE AB 64Mb 3.3 V CMOS DRAMs from two different manufacturers were tested for total dose. Retention time, power supply current, and functionality were used to characterize device response. Burned-in devices failed functionally at lower total dose levels. Results showed that these scaled DRAMs are about twice as hard as older generation 16Mb commercial DRAMs. RP Lee, CI (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4061-2 PY 1997 BP 97 EP 100 DI 10.1109/REDW.1997.629805 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BK02A UT WOS:A1997BK02A00016 ER PT B AU Ponchak, GE Downey, AN Katehi, LPB AF Ponchak, GE Downey, AN Katehi, LPB BE Schellenberg, JM TI High frequency interconnects on silicon substrates SO 1997 IEEE RADIO FREQUENCY INTEGRATED CIRCUITS (RFIC) SYMPOSIUM: DIGEST OF TECHNICAL PAPERS LA English DT Proceedings Paper CT 1997 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium / International Microwave Symposium (IMS) CY JUN 08-11, 1997 CL DENVER, CO SP IEEE Microwave Theory & Tech Soc, IEEE Electron Device Soc AB The measured propagation constant of coplanar waveguide (CPW) on silicon wafers as a function of the line dimensions and the resistivity of the Si wafer; CPW on GaAs wafers as a function of the line dimensions; and thin film microstrip (TFMS) fabricated with polyimide on the surface of a silicon wafer is presented. It is shown that the attenuation of CPW on 2500 Ohm-cm Si wafers and of TFMS with a polyimide thickness of 4 mu m or greater is comparable to the attenuation of similar lines on GaAs. RP Ponchak, GE (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,MS 54-5,CLEVELAND,OH 44135, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4063-9 PY 1997 BP 101 EP 104 DI 10.1109/RFIC.1997.598751 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BH92Z UT WOS:A1997BH92Z00023 ER PT B AU Li, PP Whitman, S Mendoza, R Tsiao, J AF Li, PP Whitman, S Mendoza, R Tsiao, J BE Spencer, SN TI ParVox - A parallel splatting volume rendering system for distributed visualization SO 1997 IEEE SYMPOSIUM ON PARALLEL RENDERING (PRS '97), PROCEEDINGS LA English DT Proceedings Paper CT IEEE 3rd Parallel Rendering Symposium (PRS 97) / IEEE Visualization 97 CY OCT 20-21, 1997 CL PHOENIX, AZ SP IEEE Comp Soc, Tech Comm Comp Graph, ACM SIGGRAPH DE direct volume rendering; wavelet image compression; parallel splatting algorithm; distributed scientific visualization AB This paper presents a parallel volume rendering system, ParVox, for large volumes of 4-D data sets in regular structured grids. A parallel volume rendering API based on the splatting algorithm constitutes the core of the ParVox system. A network interface program takes commands from an X Window based GUI, calls the API to perform the rendering functions, compresses the rendered images and sends them back to the GUI window. The ParVox system is designed for interactive, distributed visualization of large multiple time steps, multiple parameters volume datasets. The parallel splatting algorithm employs both object space decomposition and image space decomposition; an asynchronous image compositing scheme based on the direct send model reduces both the communication overhead and the synchronization overhead. The ParVox system architecture, the parallel algorithm and its implementation on the Gray T3D and the parallel wavelet compression algorithm are discussed extensively in this paper. The performance results and some optimization techniques are also presented. RP Li, PP (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 BN 1-58113-010-4 PY 1997 BP 7 EP + PG 10 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BJ83C UT WOS:A1997BJ83C00001 ER PT B AU Ma, KL Crockett, TW AF Ma, KL Crockett, TW BE Spencer, SN TI A scalable parallel cell-projection volume rendering algorithm for three-dimensional unstructured data SO 1997 IEEE SYMPOSIUM ON PARALLEL RENDERING (PRS '97), PROCEEDINGS LA English DT Proceedings Paper CT IEEE 3rd Parallel Rendering Symposium (PRS 97) / IEEE Visualization 97 CY OCT 20-21, 1997 CL PHOENIX, AZ SP IEEE Comp Soc, Tech Comm Comp Graph, ACM SIGGRAPH DE volume rendering; parallel algorithms; unstructured grids; scientific visualization; hierarchical data structures; load balancing; asynchronous communication; message passing; distributed memory AB Visualizing three-dimensional unstructured data from aerodynamics calculations is challenging because the associated meshes are typically large in size and irregular in both shape and resolution. The goal of this research is to develop a fast, efficient parallel volume rendering algorithm for massively parallel distributed-memory supercomputers consisting of a large number of very powerful processors. We use cell-projection instead of ray-casting to provide maximum flexibility in the data distribution and rendering steps. Effective static load balancing is achieved with a round robin distribution of data cells among the processors. A spatial partitioning tree is used to guide the rendering, optimize the image compositing step, and reduce memory consumption. Communication cost is reduced by buffering messages and by overlapping communication with rendering calculations as much as possible. Tests on the IBM SP2 demonstrate that these strategies provide high rendering rates and good scalability. For a dataset containing half a million tetrahedral cells, we achieve two frames per second for a 400 x 400-pixel image using 128 processors. RP Ma, KL (reprint author), NASA,LANGLEY RES CTR,INST COMP APPLICAT SCI & ENGN,MAIL STOP 403,6 N DRYDEN ST,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 2 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 BN 1-58113-010-4 PY 1997 BP 95 EP + DI 10.1109/PRS.1997.628300 PG 12 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BJ83C UT WOS:A1997BJ83C00011 ER PT B AU Ponchak, GE Tentzeris, E Katehi, LPB AF Ponchak, GE Tentzeris, E Katehi, LPB GP INT MICROELECTR & PKG SOC TI Coupling between adjacent finite ground coplanar (FGC) waveguides SO 1997 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1997 International Symposium on Microelectronics CY OCT 14-16, 1997 CL PHILADELPHIA, PA SP Int Microelectr & Pkg Soc DE coplanar waveguide; finite ground coplanar waveguide; coupled transmission lines; microwave transmission lines AB Coupling between adjacent Finite Ground Coplanar (FGC) waveguides as a function of the line geometry is presented for the first time. A two Dimension-Finite Difference Time Domain (2D-FDTD) analysis and measurements are used to show that the coupling decreases as the line to line separation and the ground plane width increases. Furthermore, if is shown that for a given spacing between the center lines of two FGC lines, the coupling is lower if the ground plane width is smaller. RP Ponchak, GE (reprint author), NASA,LEWIS RES CTR,21000 BROOKPARK RD,MS 54-5,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 J9 P SOC PHOTO-OPT INS PY 1997 VL 3235 BP 7 EP 10 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Optics SC Engineering; Materials Science; Optics GA BJ79A UT WOS:A1997BJ79A00002 ER PT B AU Ghaffarian, R AF Ghaffarian, R GP INT MICROELECTR & PKG SOC TI A review and prediction of chip scale solder joint reliability SO 1997 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1997 International Symposium on Microelectronics CY OCT 14-16, 1997 CL PHILADELPHIA, PA SP Int Microelectr & Pkg Soc AB Availability of board level solder joint reliability information is critical to the acceptance of CSPs as alternative packages. This paper will review different CSPs as well as their assembly reliability. Based on this information, solder joint reliability of these packages will be projected for a specific environment using a modified Coffin-Manson relationship. Projected board level reliability for different package type and the pin count will be presented in graphs. RP Ghaffarian, R (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 1 Z9 1 U1 2 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 J9 P SOC PHOTO-OPT INS PY 1997 VL 3235 BP 109 EP 110 PG 2 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Optics SC Engineering; Materials Science; Optics GA BJ79A UT WOS:A1997BJ79A00020 ER PT B AU Fan, MS Rose, G AF Fan, MS Rose, G GP INT MICROELECTR & PKG SOC TI Transient thermal and stress analysis for TSOP devices SO 1997 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1997 International Symposium on Microelectronics CY OCT 14-16, 1997 CL PHILADELPHIA, PA SP Int Microelectr & Pkg Soc DE PEMs; TSOP; FEA; surface mount solder joint; heat conduction; thermal stress; delamination AB Plastic Encapsulated Microcircuits (PEMs) are now being used in NASA spaceborne electronic systems mainly for their cost effectiveness. Among those PEMs, thin-small-outline-plastic (TSOP) surface mount devices are of particular interest because of certain benefits associated with light weight and compact volume. In a typical solder reflow process, a TSOP device is subject to a thermal transition from room temperature to 260 degrees C, and multiple sites of interfacial delamination and cracking have been observed in the plastic and I/O lead interface. This could be critical since moisture diffused through the cracks could cause corrosion in the metallization. The purpose of this study is to understand the mechanical impact of that thermal transition on the TSOP device through transient thermal and stress analyses. It has been revealed that the TSOP device generally has a good heat conduction capacity because of the thin encapsulation. However, excessive shear stresses are induced in the plastic-lead and plastic-die paddle interfaces, which could cause delamination and cracking as have been found during the inspection of reflowed TSOP devices. Due to the complex nature of this problem, a more accurate simulation will need to include plastic creep and nonlinear time-dependent fracture models. RP Fan, MS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TECHNOL VALIDAT ASSURANCE PROGRAM,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 J9 P SOC PHOTO-OPT INS PY 1997 VL 3235 BP 290 EP 295 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Optics SC Engineering; Materials Science; Optics GA BJ79A UT WOS:A1997BJ79A00053 ER PT B AU Ghaffarian, R Kim, NP AF Ghaffarian, R Kim, NP GP INT MICROELECTR & PKG SOC TI Ball grid array reliability assessment for aerospace applications SO 1997 INTERNATIONAL SYMPOSIUM ON MICROELECTRONICS, PROCEEDINGS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1997 International Symposium on Microelectronics CY OCT 14-16, 1997 CL PHILADELPHIA, PA SP Int Microelectr & Pkg Soc AB Reliability of Ball Grid Arrays (BGAs) was evaluated with special emphasis on space applications. This work was performed as part of a consortium led by the Jet Propulsion Laboratory (JPL) to help build the infrastructure necessary for implementing this technology. Nearly 200 test vehicles, each with four package types, were assembled and tested using an experiment design. The most critical variables incorporated in this experiment were package type, board material, surface finish, solder volume, and environmental condition. The packages used for this experiment were commercially available packages with over 250 I/Os including both plastic and ceramic EGA packages. The test vehicles were subjected to thermal and dynamic environments representative of aerospace applications. Two different thermal cycling conditions were used, the JPL cycle ranged from -30 degrees C to 100 degrees C and the Boeing cycle ranged from -55 degrees C to 125 degrees C. The test vehicles were monitored continuously to detect electrical failure and their failure mechanisms were characterized. They were removed periodically for optical inspection, Scanning Electron Microscopy (SEM) evaluation, and cross-sectioning for crack propagation mapping. Data collected from both facilities were analyzed and fitted to distributions using the Weibull distribution and Coffin-Manson relationships for failure projection. This paper will describe experiment results as well as those analyses. RP Ghaffarian, R (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91125, USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 J9 P SOC PHOTO-OPT INS PY 1997 VL 3235 BP 396 EP 401 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Optics SC Engineering; Materials Science; Optics GA BJ79A UT WOS:A1997BJ79A00071 ER PT J AU Jones, WR Paciorek, KJL Lin, WH Masuda, SR Nakahara, JH AF Jones, WR Paciorek, KJL Lin, WH Masuda, SR Nakahara, JH GP SOC TRIBOLOGISTS & LUBRICAT ENGINEERS TI Evaluation of degradation inhibitors in poly (hexafluoropropene oxide) fluids SO 1997 WORLD TRIBOLOGY CONGRESS - THE SOCIETY OF TRIBOLOGISTS AND LUBRICATION ENGINEERS, TECHNICAL PREPRINTS LA English DT Proceedings Paper CT 1997 World Tribology Congress CY SEP 08-12, 1997 CL LONDON, ENGLAND SP Soc Tribologists & Lubricat Engineers DE additives; ferrous alloys; lubricant degradation/stability AB The action of various alloys - 440C steel, M-50 steel, Pyrowear 675, Cronidur 30 and Ti (4Al, 4Mn) - and the effect of degradation inhibitors mono-and diphospha-s-triazines, diphosphatetraazacyclooctatetraene, phosphate esters, phosphate/diester rust inhibiting mixtures, and a phosphine were evaluated in Two poly (hexafluoropropene oxide) fluids (143AC and 16256). The degradation promoting action of the ferrous alloys in 16256 fluid were comparable and the Ti (4Al, 4Mn) alloy was significantly more detrimental. The overall rating of the additives was phosphates>phosphate/diester mixture>phosphine greater than or equal to phospha-s-triazines. The 16256 fluid was less responsive to additive inhibition than 143AC. Phosphate esters were fully effective over 24-hour exposure in the 16256/440C steel and the 16256/Ti (4Al, 4Mn) systems at 330 degrees C. In general, the phosphine was less effective in the presence of ferrous allays than the phosphates and phospha-s-triazines. RP Jones, WR (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068-2376 PY 1997 BP 191 EP 194 PG 4 WC Engineering, Mechanical SC Engineering GA BJ74T UT WOS:A1997BJ74T00019 ER PT J AU Simpson, J AF Simpson, J GP AMER METEOROL SOC TI Cumulus models: From kid stuff to right stuff SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Simpson, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 1 EP 6 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00001 ER PT J AU Rodgers, E Olson, WS Karyampudi, VM Pierce, H AF Rodgers, E Olson, WS Karyampudi, VM Pierce, H GP AMER METEOROL SOC TI The response of Opal's (1995) intensity to its satellite observed latent heat distribution SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Rodgers, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 29 EP 30 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00007 ER PT J AU Rothermel, J Cutten, DR Hardesty, RM Howell, JN Menzies, RT Tratt, DM Johnson, SC AF Rothermel, J Cutten, DR Hardesty, RM Howell, JN Menzies, RT Tratt, DM Johnson, SC GP AMER METEOROL SOC TI Application of airborne Doppler laser radar to hurricane research SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Rothermel, J (reprint author), NASA,MARSHALL SPACE FLIGHT CTR,GLOBAL HYDROL & CLIMATE CTR,977 EXPLORER BLVD,HUNTSVILLE,AL 35806, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 57 EP 58 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00021 ER PT J AU Ferrier, BS Halverson, JB Tao, WK Simpson, J AF Ferrier, BS Halverson, JB Tao, WK Simpson, J GP AMER METEOROL SOC TI Observations and numerical simulations of a mesoscale convective system in the COARE IFA: Sensitivity to initial conditions SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Ferrier, BS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE ATMOSPHER PROC BRANCH,CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 74 EP 75 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00030 ER PT J AU Morales, CA Kriz, JS Rodgers, EB Weinman, JA AF Morales, CA Kriz, JS Rodgers, EB Weinman, JA GP AMER METEOROL SOC TI The evolution of sferics around Hurricane Lilli 1996 SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc C1 CNPQ,COLLEGE PK,MD. RP Morales, CA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 127 EP 128 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00055 ER PT B AU Sui, CH Li, X Lau, KM Tao, WK AF Sui, CH Li, X Lau, KM Tao, WK GP AMER METEOROL SOC TI Convective-radiative responses to the large-scale forcing in the tropical ocean atmosphere SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Sui, CH (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 913,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 166 EP 167 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00076 ER PT B AU Li, X Sui, CH Lau, KM AF Li, X Sui, CH Lau, KM GP AMER METEOROL SOC TI Cloud radiative forcing and water/heat balance in the tropical deep convective regime SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Li, X (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 913,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 172 EP 173 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00079 ER PT B AU Simpson, J Ritchie, E Holland, GJ AF Simpson, J Ritchie, E Holland, GJ GP AMER METEOROL SOC TI Mesoscale interactions in tropical cyclone genesis SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Simpson, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MAIL CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 195 EP 196 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00091 ER PT B AU Hasler, AF Black, PG Karyampudi, VM JentoftNilsen, M Palaniappan, K Chesters, D AF Hasler, AF Black, PG Karyampudi, VM JentoftNilsen, M Palaniappan, K Chesters, D GP AMER METEOROL SOC TI Synthesis of eyewall mesovortex and supercell convective structures in Hurricane Luis with GOES-8/9 stereo, concurrent 1-min GOES-9 and NOAA airborne radar observations SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Hasler, AF (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 0 TC 9 Z9 9 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 201 EP 202 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00094 ER PT B AU Rickenbach, TM Rutledge, SA AF Rickenbach, TM Rutledge, SA GP AMER METEOROL SOC TI The diurnal variation of rainfall over the western Pacific warm pool: Dependence on convective organization SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Rickenbach, TM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,NATL RES COUNCIL,CODE 910-1,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 205 EP 206 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00096 ER PT J AU Halverson, JB Ferrier, BS Simpson, J Tao, WK AF Halverson, JB Ferrier, BS Simpson, J Tao, WK GP AMER METEOROL SOC TI On the sensitivity of diagnostic energy budgets to divergence and sounding bias for a TOGA COARE squall system SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Halverson, JB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MESOSCALE ATMOSPHER PROC BRANCH,CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 215 EP 216 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00101 ER PT J AU Anyamba, E Williams, E Susskind, J FraserSmith, A Fullekrug, M AF Anyamba, E Williams, E Susskind, J FraserSmith, A Fullekrug, M GP AMER METEOROL SOC TI The manifestation of the Madden-Julian oscillation in global deep convection and in the Schumann resonance intensity SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Anyamba, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 910-4,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 227 EP 231 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00107 ER PT J AU Ferreira, RN Schubert, WH AF Ferreira, RN Schubert, WH GP AMER METEOROL SOC TI On the formation and evolution of tropical upper tropospheric troughs SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Ferreira, RN (reprint author), UNIV SPACE RES ASSOC,NASA,GSFC,MAILSTOP 913-0,GREENBELT,MD 20711, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 270 EP 271 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00127 ER PT J AU Alexander, GD Weinman, JA AF Alexander, GD Weinman, JA GP AMER METEOROL SOC TI The use of digital warping of microwave total precipitable water imagery to improve forecasts of a marine cyclone SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Weinman, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 975,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 314 EP 315 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00150 ER PT J AU Oki, R Kucera, PA Short, DA AF Oki, R Kucera, PA Short, DA GP AMER METEOROL SOC TI Triple shipborne radar observations of tropical mesoscale convective systems during TOGA COARE SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Oki, R (reprint author), NASA,GODDARD SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,CODE 910-1,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 323 EP 324 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00154 ER PT J AU Shepherd, JM AF Shepherd, JM GP AMER METEOROL SOC TI Low-level moisture: Is it a convective control? Preliminary results SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Shepherd, JM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 339 EP 340 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00162 ER PT B AU Fisher, BL Short, DA Wolff, DB Thiele, OW AF Fisher, BL Short, DA Wolff, DB Thiele, OW GP AMER METEOROL SOC TI The diurnal cycle of precipitation, temperature, and pressure over Melville and Bathurst Islands during MCTEX SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Fisher, BL (reprint author), NASA,GSFC,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 370 EP 371 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00178 ER PT J AU Hong, Y Kummerow, CD Olson, WS AF Hong, Y Kummerow, CD Olson, WS GP AMER METEOROL SOC TI Separation of convective/stratiform precipitation using microwave brightness temperature SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Hong, Y (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 912,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 525 EP 526 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00256 ER PT B AU Krishnakumar, V Lau, KM AF Krishnakumar, V Lau, KM GP AMER METEOROL SOC TI Possible role of symmetric instability in the onset and abrupt transition of the Asian monsoon SO 22ND CONFERENCE ON HURRICANES AND TROPICAL METEOROLOGY LA English DT Proceedings Paper CT 22nd Conference on Hurricanes and Tropical Meteorology CY MAY 19-23, 1997 CL FT COLLINS, CO SP Amer Meteorol Soc RP Krishnakumar, V (reprint author), NASA,GODDARD SPACE FLIGHT CTR,APPL RES CORP,CLIMATE & RADIAT BRANCH,CODE 913,GREENBELT,MD 20771, USA. RI Lau, William /E-1510-2012; Kumar, V. Krishna/N-9865-2016 OI Lau, William /0000-0002-3587-3691; Kumar, V. Krishna/0000-0002-4455-0843 NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 PY 1997 BP 668 EP 669 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BK02K UT WOS:A1997BK02K00325 ER PT B AU Weinstein, L Minto, D AF Weinstein, L Minto, D BE Paisley, DL Frank, AM TI Focusing Schlieren photography at the Holloman high speed test track SO 22ND INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 22nd International Congress on High-Speed Photography and Photonics CY OCT 27-NOV 01, 1996 CL SANTA FE, NM SP Los Alamos Natl Lab, Soc Photo Opt Instrumentat Engineers, Int Working Grp High Speed Photog Vid, eog & Photon, Lawrence Livermore Natl Lab, Natl Sci Fdn DE flow visualization; Schlieren; Focusing Schlieren; rocket sled; high speed test track; shock waves AB Motion camera Focusing Schlieren photographs were obtained for test vehicles at the high speed test track at Holloman AFB. These photographs were used to examine the shock waves and turbulent flow generated by a variety of rocket driven sled vehicles at speeds from Mach 1.3 to Mach 5.5. Some of the images show non-uniform exposure, but the shock wave structures are still clearly seen. An improved light source setup is described which should improve the uniformity of the exposures. RP Weinstein, L (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23681, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2266-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 2869 BP 865 EP 873 PG 9 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BJ32H UT WOS:A1997BJ32H00121 ER PT B AU Broughton, H Sims, JJ AF Broughton, H Sims, JJ BE Paisley, DL Frank, AM TI High speed gear failure digital video imaging system SO 22ND INTERNATIONAL CONGRESS ON HIGH-SPEED PHOTOGRAPHY AND PHOTONICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 22nd International Congress on High-Speed Photography and Photonics CY OCT 27-NOV 01, 1996 CL SANTA FE, NM SP Los Alamos Natl Lab, Soc Photo Opt Instrumentat Engineers, Int Working Grp High Speed Photog Vid, eog & Photon, Lawrence Livermore Natl Lab, Natl Sci Fdn DE gear; high-speed; imaging; meshing; video; digital AB In support of the gear mesh diagnostics research conducted at NASA Lewis Research Center a new high speed digital video imaging system has been developed to capture images of individual teeth on two meshing planetary gears rotating at high speeds. Each gear tooth image documents the progression of tooth wear, gear pitting, and tooth fractures that lead to overall gear failure. Previous imaging techniques used to document gear failure were restricted to post test analysis and did not allow a real time study of the degradation which leads to total gear failure. This imaging system is integrated with existing vibration detection hardware and operates autonomously to capture images of each gear tooth at predetermined vibration thresholds. Analysis of the data will allow researchers to define specific events in the failure process which lead to a better understanding of the causal factors of gear failure. RP Broughton, H (reprint author), NASA,LEWIS RES CTR,CORTEZ SERV CORP 3,CLEVELAND,OH 44135, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2266-5 J9 P SOC PHOTO-OPT INS PY 1997 VL 2869 BP 1013 EP 1016 PG 4 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BJ32H UT WOS:A1997BJ32H00140 ER PT B AU Bidwell, SW Heymsfield, GM Caylor, IJ AF Bidwell, SW Heymsfield, GM Caylor, IJ GP AMER METEOROL SOC TI The ER-2 Doppler Radar (EDOP) capabilities and performance upgrades SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bidwell, SW (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 115 EP 116 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800056 ER PT B AU Amitai, E AF Amitai, E GP AMER METEOROL SOC TI Relationships between radar properties at high elevations and surface rain rate distributions SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Amitai, E (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 910-1, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 192 EP 193 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800093 ER PT B AU Jones, JA Meneghini, R Iguchi, T Tao, WK AF Jones, JA Meneghini, R Iguchi, T Tao, WK GP AMER METEOROL SOC TI Synthetic data for testing TRMM radar algorithms SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 Hughes STX Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jones, JA (reprint author), Hughes STX Corp, Goddard Space Flight Ctr, Code 690-2, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 196 EP 197 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800095 ER PT B AU Takahashi, N Horie, H Meneghini, R AF Takahashi, N Horie, H Meneghini, R GP AMER METEOROL SOC TI Rainfall measurement with a ground based dual frequency radar SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Takahashi, N (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 975, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 206 EP 207 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800100 ER PT B AU Meneghini, R Jones, JA AF Meneghini, R Jones, JA GP AMER METEOROL SOC TI Application of a threshold method to the TRMM radar for the estimation of space-time rain rate statistics SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Meneghini, R (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 280 EP 281 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800137 ER PT B AU Atlas, D Ulbrich, CW Williams, C Marks, FD AF Atlas, D Ulbrich, CW Williams, C Marks, FD GP AMER METEOROL SOC TI On the variability of tropical rain microphysics and radar rain retrievals SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Atlas, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 334 EP 337 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800159 ER PT B AU Liao, L Meneghini, R Iguchi, T Detwiler, A AF Liao, L Meneghini, R Iguchi, T Detwiler, A GP AMER METEOROL SOC TI Estimation of snow parameters from dual-wavelength airborne radar SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Liao, L (reprint author), NASA, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 510 EP 511 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800245 ER PT B AU Heymsfield, GM Caylor, IJ Bidwell, SW AF Heymsfield, GM Caylor, IJ Bidwell, SW GP AMER METEOROL SOC TI Vertical motions in deep convective storms observed with EDOP during CAMEX-2 SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heymsfield, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 563 EP 564 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800271 ER PT B AU Wolff, DB Fisher, BL Thiele, OW AF Wolff, DB Fisher, BL Thiele, OW GP AMER METEOROL SOC TI A radar analysis of coastal hurricanes using WSR-88D radar data SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Wolff, DB (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, 910-1, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 586 EP 587 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800282 ER PT B AU Rickenbach, TM Short, DA Thiele, OW AF Rickenbach, TM Short, DA Thiele, OW GP AMER METEOROL SOC TI Propagation characteristics of tropical convective systems from radar and infrared satellite images SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, TRMM Off, Greenbelt, MD 20771 USA. RP Rickenbach, TM (reprint author), NASA, Goddard Space Flight Ctr, TRMM Off, Code 910-1, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 596 EP 597 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800287 ER PT B AU Halverson, JB Ferrier, BS Simpson, J Tao, WK AF Halverson, JB Ferrier, BS Simpson, J Tao, WK GP AMER METEOROL SOC TI Rainfall characteristics of an ensemble of convective systems on 11 February 1993 during TOGA COARE SO 28TH CONFERENCE ON RADAR METEOROLOGY LA English DT Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TX SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Halverson, JB (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Code 912, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 598 EP 599 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BL61L UT WOS:000076012800288 ER PT S AU Ogilvie, KW Roelof, EC Forsyth, RJ AF Ogilvie, KW Roelof, EC Forsyth, RJ BE Wilson, A TI Interface structure of co-rotating interaction regions SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC AB Plasma and particle observations on Ulysses during its passes through the southern and northern heliosphere have revealed that, inside the streamer belt, the large-scale structure of the quiet global heliosphere is dominated by corotating interaction regions (CIRs). Therefore, considerable attention is now being given to the internal plasma structure of CIRs, and in particular, to the mainfestations of the stream interfaces that should mark their origins as interactions between low speed solar wind (in the low-latitude streamer belt) and high speed solar wind (from the equatorial extensions of the high latitude polar coronal holes). The SWIGS and HI-SCALE experiments on Ulysses combine plasma and energetic particle measurements that are of considerable utility for such studies because, between them, they cover the proton energy range from 10 eV to 5 MeV. We use these measurements, together with magnetic field data, to study the remarkable series of CIRs that occurred during the period beginning July 1992 and the end of 1993 as Ulysses rose from the ecliptic to a southern heliographic latitude of 48 degrees. We make use of the identification of interfaces recently published by Wimmer-Schweingruber et al., 1997. The structure of the regions between the forward and reverse shocks has previously been analyzed in terms of the proton specific entropy argument log (n/T-3/2) that should exhibit a discontinuous jump at the stream interface. It has been claimed that the stream interface, defined with respect to specific entropy, is also associated with a discontinuity in energetic proton intensities. This paper examines the energetic particle data (> 60 keV) and how they were ordered with respect to interfaces and with respect to the magnetic field. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ogilvie, KW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 59 EP 68 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300009 ER PT S AU Goldstein, ML Roberts, DA Deane, A AF Goldstein, ML Roberts, DA Deane, A BE Wilson, A TI Numerical simulation of MHD turbulence in three dimensions SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC DE space physics; solar wind; magnetohydrodynamic turbulence AB Magnetohydrodynamic fluctuations in the solar wind resemble Alfvenic turbulence in many respects. The correlation between the fluctuating velocity and magnetic fields is large in the inner heliosphere, but decreases with increasing heliocentric distance. For pure Alfven waves in an incompressible and inviscid magnetofluid, this correlation would not decay. Numerical solutions of both the compressible incompressible equations of magnetohydrodynamics (MHD) in rectangular geometry suggest that sharp gradients in velocity are capable of decreasing substantially the Alfvenicity of such fluctuations. It has also been argued, however, that the spherical expansion of the solar wind, itself, might affect significantly the Alfvenicity. We are now able to study the evolution of Alfvenic turbulence in three-dimensional spherical geometry. In these simulations, a fast stream is sandwiched between two slower streams. The inflow is both supersonic and super Alfvenic. Alfven waves entering the box are convected into the medium and interact nonlinearly with the velocity shear and with any structures (i.e., flux tubes) that might be present. These initial simulations suggest that velocity shear, even in spherical geometry, is able to drive a turbulent cascade which results in approximately Kolmogoroff-like power spectra. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Goldstein, ML (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. RI Goldstein, Melvyn/B-1724-2008 NR 0 TC 2 Z9 2 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 83 EP 88 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300012 ER PT S AU Gibson, SE Biesecker, D Fisher, R Howard, RA Thompson, BJ AF Gibson, SE Biesecker, D Fisher, R Howard, RA Thompson, BJ BE Wilson, A TI Fitting a 3-D analytic model of the coronal mass ejection to observations SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC DE coronal mass ejections AB We present the application of an analytic magnetohydrodynamic model (Gibson & Low 1998) to observations of the time-dependent expulsion of three-dimensional coronal mass ejections (CMEs) out of the solar corona. The model relates the white-light appearance of the CME to its internal magnetic field, which takes the form of a closed bubble, filled with a partly anchored, twisted magnetic flux rope and embedded in an otherwise open background field. The density distribution frozen into the expanding CME magnetic field is fully three-dimensional, and can be integrated along the line of sight to reproduce observations of scattered white light. The model is able to reproduce the three conspicuous features often associated with CMEs as observed with white-light coronagraphs: a surrounding high-density region, an internal low-density cavity, and a high-density core. The model also describes the self-similar radial expansion of these structures. By varying the model parameters we can fit the model directly to observations of CMEs. We are able to fit the size, shape, and velocity profile of CMEs observed by the SOHO/LASCO C2 and C3 coronagraphs and SOHO/EIT telescope. We also show how the model can quantitatively match the polarized Brightness (pB) contrast of a dark cavity emerging through the lower corona as observed by the HAO Mauna Loa K-coronameter to within the noise level of the data. The model cannot reproduce non-self-similar features of observed CMEs. We consider the physical significance of such non-self-similar features. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gibson, SE (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 682, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 111 EP 116 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300016 ER PT S AU Lepping, RP Szabo, A DeForest, CE Thompson, BJ AF Lepping, RP Szabo, A DeForest, CE Thompson, BJ BE Wilson, A TI Magnetic flux in modeled magnetic clouds at 1 AU and some specific comparisons to associated photospheric flux SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC AB Interplanetary magnetic clouds are important because of their well-known dramatic effects on the Earth's magnetosphere. There are two parts to this study, which attempts to better understand the solar origins of magnetic clouds: (1) to obtain statistical distributions of the estimated axial magnetic flux of 30 magnetic clouds at 1 AU separated according to their occurrence during the solar cycle, and (2) to make a comparison of the magnetic flux of a magnetic cloud to the aggregate flux of apparently associated photospheric magnetic flux tubes, for some specific cases. The 30 magnetic clouds comprise 12 cases from WIND (mostly from solar min.) and the remainder (mostly from solar max.) from IMP-8, earlier IMP's, ISEE-3, and HELIOS. Employing a constant alpha (J = alpha B) cylindrical force-free flux rope model to determine the clouds' diameters (D-o, = 2R(o)) and axial magnetic field strengths (B,), we are able to estimate the total magnetic flux (Phi(o)) along the cloud axis (i.e., Phi(o) = 1.39 B-o R-o(2)). For the full set of events the average D-o is 0.27 AU and the average B-o is 17.7 nT, but the distributions of these quantities are skewed toward higher values for both solar max and solar min. The distribution of magnetic fluxes for the 30 clouds is shown to be in the form of a skewed gaussian, f(Phi(o)) similar to e(.X) where X = (Phi(o)/10.5x10(20) Mx)(2), and where the mode Is 7.5(+/-6.0) x 10(20) Mx. For three specific cases, the relationship between the magnetic flux of a magnetic cloud at 1 AU (Phi(o)) and the flux in apparently associated photospheric flux tube(s) (Phi(SUN)) is presented in the form of Phi(SUN) = K Phi(o). Phi(SUN) is based on SOHO/MDI measurements in coordination with SOHO/EIT and Yohkoh/SXT observations. For the two apparently successful cases of the three, the value of K is approximate to 0.4. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Lepping, RP (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 0 TC 7 Z9 8 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 163 EP 170 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300023 ER PT S AU Osherovich, VA Fainberg, J Stone, RG MacDowall, RJ Berdichevsky, D AF Osherovich, VA Fainberg, J Stone, RG MacDowall, RJ Berdichevsky, D BE Wilson, A TI Self-similar evolution of interplanetary magnetic clouds and Ulysses measurements of the polytropic index inside the cloud SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC AB The polytropic index gamma as a key parameter for MHD modelling of interplanetary magnetic clouds determines the evolution of the magnetic field (B) over bar and the thermodynamic structure of the cloud. A self-similar model for the expanding flux rope suggested the dependence B-max approximate to r(-1/gamma) where r is the distance fi om the sun and gamma < 1 (Osherovich Farrugia, Burlaga 1993b). This dependence of B-max has been confirmed numerically by Vandas et al. 1995 with an essential difference; their value of gamma was assumed larger than unity. The first observational determination of gamma (Osherovich et al. 1993c) has revealed that gamma approximate to 1/2 in the cloud and is effectively gamma(e) of the hot electrons (T-e/T-p approximate to 6-7). Our self-similar model suggested that T-e/T-p should increase with distance from the sun and also that ion-acoustic waves should be observed in the cloud. Both predictions have been confirmed by Ulysses observations of the June 10-13, 1993 magnetic cloud (Stone et al. 1995; Fainberg et al. 1996). Further advances in the measurements of gamma and implications for cloud evolution are discussed. C1 NASA, Hughes STX, Greenbelt, MD 20771 USA. RP Osherovich, VA (reprint author), NASA, Hughes STX, Code 692, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012 NR 0 TC 7 Z9 7 U1 0 U2 2 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 171 EP 175 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300024 ER PT S AU Domingo, V Sanchez, L Appourchaux, T Frohlich, C Wehrli, C Crommelynck, D Pap, J AF Domingo, V Sanchez, L Appourchaux, T Frohlich, C Wehrli, C Crommelynck, D Pap, J BE Wilson, A TI On the effect of active regions on the solar irradiance SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC AB The limb brightening of the faculae associated with active regions has been studied with data obtained during the period of minimum solar activity in 1996-1997 by the VIRGO instrument on SOHO. The contribution of the active regions to the total solar irradiance is investigated. The period of minimum solar activity is particularly favourable, because frequently there is only a single active region on the whole solar disc, thus making more simple the identification of the effects. Preliminary results of work in progress are presented. C1 NASA, Goddard Space Flight Ctr, ESA, Greenbelt, MD 20771 USA. RP Domingo, V (reprint author), NASA, Goddard Space Flight Ctr, ESA, Code 682, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 469 EP 472 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300076 ER PT S AU Peredo, M Fox, N Thompson, B AF Peredo, M Fox, N Thompson, B BE Wilson, A TI Overview of the ISTP Sun-Earth Connection event of January 6-11, 1997 SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC AB During the interval January 6-11, 1997, the satellites and ground facilities of the International Solar-Terrestrial Physics (ISTP) "Observatory" tracked a solar eruption from the Sun to the Earth. The resulting Coronal Mass Ejection (CME) took four days to travel through interplanetary space before arriving at Earth, where it caused disturbances to the electromagnetic environment and spectacular auroral displays. The initial expulsion lifted off the Sun on January 6, 1997, the resulting magnetic cloud arrived on January 10, and its effects were felt in the Earth's neighborhood for over 24 hours. The initial solar observations from SOHO were reported on January 7, 1997 during an ISTP Science Workshop, where many scientists were gathered to discuss Sun-Earth Connection events. This alerted the community to the impending arrival of the CME thereby allowing the event to be monitored II 'real-time' using the wide variety of instruments involved in the ISTP mission. While this was not a particularly unusual event, it was tile first opportunity scientists have had to watch the end to end evolution of a space storm. In this paper we present an overview of tile available observations and geospace response of this magnetic cloud event. C1 NASA, Goddard Space Flight Ctr, Hughes STX Corp, Greenbelt, MD 20771 USA. RP Peredo, M (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX Corp, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 517 EP 521 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300084 ER PT S AU MacDowall, RJ Klimas, AJ Lengyel-Frey, D Stone, RG Thejappa, G AF MacDowall, RJ Klimas, AJ Lengyel-Frey, D Stone, RG Thejappa, G BE Wilson, A TI Comparison of interplanetary type II radio burst observations by ISEE-3, Ulysses, and wind with applications to space weather prediction SO 31ST ESLAB SYMPOSIUM ON CORRELATED PHENOMENA AT THE SUN, IN THE HELIOSPHERE AND IN GEOSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 31st ESLAB Symposium on Correlated Phenomena at the Sun, in the Heliosphere and in Geospace CY SEP 22-25, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP ESA ESTEC HO ESTEC DE type II bursts; interplanetary shocks; geomagnetic activity; space weather AB Interplanetary (IF) type II radio bursts are produced by IP shocks driven by solar ejecta, presumably involving shock acceleration of electrons that leads to radio emission. These radio bursts, which can be detected remotely by a sensitive spacecraft radio receiver, provide a method of tracking the leading edge of solar ejecta moving outward from the Sun. Consequently, observations of these bursts sometimes provide advance warning of 1 or more days prior to the onset of geomagnetic activity induced by the solar ejecta. In this paper, we provide a robust lower limit on the fraction of intense geomagnetic storms (Dst < -100 nT) that are preceded by IP type II bursts, specifically the set of 48 events catalogued by Cane (1985). We show that 41 percent of the geomagnetic storms occurring during the interval September 1978 to February 1983 were preceded by type II events in this catalog, and we discuss reasons why the fraction is not larger. We also review differences in observing capabilities of ISEE-3, Ulysses, and Wind, to explain why each of these similar spacecraft radio investigations provides a different perspective of IP type II emissions. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP MacDowall, RJ (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-660-0 J9 ESA SP PUBL PY 1997 VL 415 BP 533 EP 538 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK58J UT WOS:000072623300086 ER PT B AU Knox, JA Silberberg, SR AF Knox, JA Silberberg, SR GP AMER METEOROL SOC TI L.F. Richardson's forecast factory: An active learning experiment in four acts SO 6TH SYMPOSIUM ON EDUCATION LA English DT Proceedings Paper CT 6th Symposium on Education / 8th Symposium on Global Change Studies CY FEB 02-07, 1997 CL LONG BEACH, CA SP Amer Meteorol Soc C1 Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10027 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 48 EP 51 PG 4 WC Education & Educational Research SC Education & Educational Research GA BK58F UT WOS:000072616000017 ER PT B AU Knox, JA AF Knox, JA GP AMER METEOROL SOC TI Advanced stupid calculator tricks: Iterative solution of the gradient wind equation SO 6TH SYMPOSIUM ON EDUCATION LA English DT Proceedings Paper CT 6th Symposium on Education / 8th Symposium on Global Change Studies CY FEB 02-07, 1997 CL LONG BEACH, CA SP Amer Meteorol Soc C1 NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP 139 EP 142 PG 4 WC Education & Educational Research SC Education & Educational Research GA BK58F UT WOS:000072616000050 ER PT B AU Bess, TD Carlson, AB Denn, FM AF Bess, TD Carlson, AB Denn, FM GP AMER METEOROL SOC TI Earth radiation budget experiment (ERBE) data sets for global environment and climate change studies SO 6TH SYMPOSIUM ON EDUCATION LA English DT Proceedings Paper CT 6th Symposium on Education / 8th Symposium on Global Change Studies CY FEB 02-07, 1997 CL LONG BEACH, CA SP Amer Meteorol Soc C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 1997 BP J23 EP J26 PG 4 WC Education & Educational Research SC Education & Educational Research GA BK58F UT WOS:000072616000062 ER PT S AU Eisen, HJ Buck, CW GillisSmith, GR Umland, JW AF Eisen, HJ Buck, CW GillisSmith, GR Umland, JW BE KaldeichSchurmann, BH TI Mechanical design of the Mars Pathfinder Mission SO 7TH EUROPEAN SPACE MECHANISMS & TRIBOLOGY SYMPOSIUM, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th European Space Mechanisms and Tribology Symposium CY OCT 01-03, 1997 CL ESTEC, NOORDWIJK, NETHERLANDS SP European Space Agcy, NIVR, CNES HO ESTEC AB The Mars Pathfinder Mission was a great engineering achievement for the National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory (JPL) which built the Pathfinder Spacecraft and the Sojourner(TM) Rover. The mechanical design of the mission hardware was critical to the success of the complex entry sequence and landed operations. A wide variety of mechanisms were employed with varying technologies and heritage. These mechanisms have played a key role in the mission which has greatly exceeded expectations. RP Eisen, HJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 2 Z9 2 U1 1 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-640-6 J9 ESA SP PUBL PY 1997 VL 410 BP 293 EP 301 PG 9 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA BJ77S UT WOS:A1997BJ77S00043 ER PT S AU Wooldridge, EM AF Wooldridge, EM GP EUROPEAN SPACE AGCY TI Initial contamination control considerations for the next generation space telescope (NGST) SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB The NASA Space Science Program, in its ongoing mission to study the universe, has begun planning for a telescope that will carry on the Hubble Space Telescope's exploration. This telescope, the ''Next Generation Space Telescope'' (NGST), will be 6-8 meters in diameter, will be radiatively cooled to 30-60 Kelvin in order to enable extremely deep exposures at near infra-red wavelengths, and will operate for a lifetime of 5-10 years. The requirement will be to measure wavelengths from 1-5 microns, with a goal to measure wavelengths from 0.6-20 microns. As such, NGST will present a new contamination control challenge. The Goddard Space Flight Center (GSFC) performed one of three preliminary feasibility studies for the NGST, presenting a telescope with an 8 meter, deployable primary mirror and a deployable secondary mirror. The telescope would be radiatively cooled, with the optical telescope assembly (OTA) and the science instrument module (SIM) isolated from the warmer spacecraft support module (SSM). The OTA and the SIM would also be shielded from sunlight with an enormous, inflatable sunshield. The GSFC telescope was designed for launch on an Atlas IIAS, which would require launching the telescope in a stowed configuration, with the SSM, antennae, sunshield, primary mirror ''petals'', and secondary mirror deployed once on-orbit. The launch configuration and deployment scenario of an exposed telescope measuring near infrared and cooled to 30-60K are the factors presenting contamination hazards to the NGST mission. Preliminary science requirements established are: <20% reflectance decrease on optical surfaces over the wavelength range, and <0.3% obscuration of optical surfaces, In order to meet these requirements, NGST must be built and launched with careful attention to contamination control. Initial contamination control design options include strict selecting of materials and baking out of hardware down to the component level, minimizing or eliminating exposure of the OTA to sunlight or earth albedo during deployment and early on-orbit operations, cleaning of the primary and secondary mirrors at the launch site, cleaning of the launch vehicle fairing, locating thrusters and vents on the warm side of the sunshield only, and the possibility of including a deployable cover if that is shown to be necessary. RP Wooldridge, EM (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 724,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 127 EP 133 PG 3 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00014 ER PT S AU Hansen, PA Maag, CR AF Hansen, PA Maag, CR GP EUROPEAN SPACE AGCY TI Contamination control program for the Hubble Space Telescope second servicing mission SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB The Hubble Space Telescope (HST) has provided many wondrous discoveries cn the constituents of our universe. On-orbit manned servicing missions are required periodically to maintain the HST scientific capabilities. Two servicing mission have been performed: Servicing Mission 1 (STS-61), December 1993 and Servicing Mission 2 (STS-82), February 1997. Servicing carriers, designed for these missions, are reflown for each servicing mission. The Hubble Space Telescope Servicing Mission contamination control program is unique as it must maintain the current operational capability of the telescope while allowing for manned servicing. The integrity and outgassing certification of reflown, hardware is maintained between servicing missions while accommodating configuration changes to the hardware. Environmental control of the hardware, materials screening and outgassing certification of added hardware were the important features of the contamination control program. RP Hansen, PA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 135 EP 142 PG 4 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00015 ER PT S AU deGroh, KK Smith, DC AF deGroh, KK Smith, DC GP EUROPEAN SPACE AGCY TI Investigation of Teflon FEP embrittlement on spacecraft in low earth orbit SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB Teflon(R) FEP (fluorinated ethylene-propylene) is commonly used on exterior spacecraft surfaces in the low Earth orbit (LEG) environment for thermal control. Silverized or aluminized FEP is used for the outer layer of thermal control blankets because of its low solar absorptance and high thermal emittance. FEP is also preferred over other spacecraft polymers because of its relatively high resistance to atomic oxygen erosion. Because of this low atomic oxygen erosion yield, FEP has not been protected in the space environment. Recent, long term space exposures such as on the Long Duration Exposure Facility (LDEF, 5.8 years in space), and the Hubble Space Telescope (HST, after 3.6 years in space) have provided evidence of LEO environmental degradation of FEP. These exposures provide unique opportunities for studying environmental degradation because of the long durations and the different conditions (such as differences in altitude) of the exposures. Samples of FEP from LDEF and from HST (retrieved during its first servicing mission) have been evaluated for solar induced embrittlement and for synergistic effects of solar degradation and atomic oxygen. Micro-indenter results indicated that the surface hardness increased as the ratio of atomic oxygen fluence to solar fluence decreased for the LDEF samples. FEP multilayer insulation (MLI) retrieved from HST provided evidence of severe embrittlement on solar facing surfaces. Micro-indenter measurements indicated higher surface hardness values for these samples than LDEF samples, but the solar exposures were higher. Cracks induced during bend testing were significantly deeper for the HST samples with the highest solar exposure than for LDEF samples with similar atomic oxygen fluence to solar fluence ratios. If solar fluences are compared, the LDEF samples appear as damaged as HST samples, except that HST had deeper induced cracks. The results illustrate difficulties in comparing LEO exposed materials from different missions. Because the HST FEP appears more damaged than LDEF FEP based on depth of embrittlement, other causes for FEP embrittlement in addition to atomic oxygen and ultraviolet (UV) radiation, such as thermal effects and the possible role of soft x-ray radiation, need to be considered. FEP that was exposed to soft xrays in a ground test facility, showed embrittlement similar to that witnessed in LEG, which indicates that the observed differences between LDEF and HST FEP might be attributed to the different soft x-ray fluences during these two missions. RP deGroh, KK (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,MS 309-2,CLEVELAND,OH 44135, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 255 EP 266 PG 4 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00032 ER PT S AU Gaunce, MT Naumov, S Scharf, R Suggs, R Borisov, V AF Gaunce, MT Naumov, S Scharf, R Suggs, R Borisov, V GP EUROPEAN SPACE AGCY TI Assessment of Mir orbital station external condition using Space Shuttle photographic and video imagery SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB This paper presents the results of photographic and video surveys conducted on the Mir Space Station during six Space Shuttle missions from STS-63 in February 1995 to STS-81 in January 1997. The imagery data taken during these missions has been used to produce both qualitative and quantitative assessments of external deposition and contamination, surface degradation, dynamic events, and micrometeoroid and orbital debris strikes. The imagery was used to assess and verify the configuration of the Mir. During these six missions, over 20 areas of surface damage and discoloration have been identified. These include: solar array damage, surface and thermal protection blanket damage and discoloration, flaking paint coating of a radiator, etc. In addition, over 50 potential micrometeoroid/orbital debris strikes have been identified, with damage area ranges up to 25 cm(2). Finally, several dynamic events. including solar array motion, free-floating debris, and thruster plume effects were characterized. Photographs of the Mir modules which illustrate these observations and measurements are included in the paper. This paper also addresses the general ''lessons learned'' from analysis of Mir imagery that can be applied to the International Space Station (ISS). The photographic and video data confirm the general good condition of the external surfaces of the Mir. However, there are unanticipated degradations of the on-orbit performance of the hardware, and these have a direct bearing on the design and successful operation of the ISS. RP Gaunce, MT (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 309 EP 320 PG 4 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00038 ER PT S AU Thomson, S Hansen, P Straka, S Chen, P Triolo, J Bettini, R Carosso, P Carosso, N AF Thomson, S Hansen, P Straka, S Chen, P Triolo, J Bettini, R Carosso, P Carosso, N GP EUROPEAN SPACE AGCY TI To-date spacecraft applications and demonstration testing results, and future product development for new molecular adsorber technologies SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB The use of molecular adsorbers to aid in reducing spacecraft contamination levels has recently been implemented for a number of National Aeronautics and Space Administration (NASA) missions. Molecular adsorbers are a family of inorganic materials/minerals characterized by extremely large surface area, molecularly porous substructure, and possessing charged sites capable of retaining molecular contaminant species upon contact. Adsorbent materials of this type have many non-aerospace uses, including, for example, charcoal filters to absorb smoke contaminants in room environments. This same concept has now been applied to the field of spacecraft contamination engineering. Molecular adsorbers for spacecraft applications are fabricated by combining carefully selected adsorbent material with a substrate that is both capable of bonding with the adsorbent and suitable for the desired spacecraft application/environment. Once the completed ''unit'' (adsorbent and substrate) has been fabricated, it is then placed in specific spacecraft locations. It has been demonstrated that the placement of molecular adsorbing materials in high-outgassing spacecraft compartments or along vent paths serves to ''trap and hold'' outgassed molecules, thereby eliminating them as contamination threats to other spacecraft locations. The development and qualification of this tg pe of contamination control technique has been and is continuing to be fully explored at the NASA/Goddard Space Flight Center (GSFC) along with Swales Aerospace (SA). This technique has already been employed on two Hubble Space Telescope (HST) servicing missions, as well as for the Tropical Rainfall Measuring Mission (TRMM). The use of molecular adsorbers is being planned for future NASA spacecraft missions. Ln the future, the incorporation of molecular adsorbers may well be a basic dement of contamination control for all spacecraft designs. The use of molecular adsorbers carries the potential for a low cost, easy to fabricate, easy to integrate, highly reliable means of seducing the overall contamination level around spacecraft. This contamination control technique can also be applied during ground testing activities. RP Thomson, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 435 EP 443 PG 3 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00052 ER PT S AU Hirsch, D Kudriavtsev, V Sedov, G Karpov, I Golden, J Linley, L May, T AF Hirsch, D Kudriavtsev, V Sedov, G Karpov, I Golden, J Linley, L May, T GP EUROPEAN SPACE AGCY TI Joint US/Russian testing for track propagation SO 7TH INTERNATIONAL SYMPOSIUM ON MATERIALS IN SPACE ENVIRONMENT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 7th International Symposium on Materials in Space Environment CY JUN 16-20, 1997 CL TOULOUSE, FRANCE SP European Space Agcy, ONERA, CNES AB Power thresholds below which track propagation does not occur were determined for various wires used in Russian spacecraft. Tests were conducted in ambient air and vacuum with DC current on several types of insulations and sample configurations. The wire insulations evaluated included Russian 100 percent polyimide, modified polyimide-based insulations containing 7 to 8 percent polytetrafluoroethylene (PTFE), and 100 percent PTFE. The wires were tested in several configurations, all consisting of seven-wire bundles. All seven wires in Configuration 1 were insulated with polyimide or modified polyimide-based insulation; three of the wires were connected to (+) and the remaining four wires were connected to (-). Configuration 2 had four polyimide or modified polyimide-based insulated wires connected to (-) and three PTFE-insulated wires connected to (+). Configuration 3 consisted of seven polyimide-insulated wires; three wires were wrapped with Russian PTFE tape and connected to (+), and the remaining four wires were connected to (-). The data indicate that the track propagation thresholds were lower in vacuum than in air. While the threshold shift resulting from changing the environment from air to vacuum was approximately the same for standard and modified wires tested in Configuration 1, the effect was larger for Configuration 2 wires. For Configuration 3, the testing conditions were not severe enough to allow reaching threshold levels. Under the conditions tested, the modified wires outperformed the standard polyimide-insulated wires. Under the same conditions, the track propagation threshold levels were higher for Configuration 2 than for Configuration 1. The tests indicated that Configuration 3 was the safest the separation of (+) and (-) polyimide-insulated wires by loosely wrapping the positive wires together with fluoropolymer successfully prevented tracking in air and vacuum at NHB 8060.1C Test 18 standard test conditions with 200 VDC power supply. RP Hirsch, D (reprint author), NASA,JOHNSON SPACE CTR,ALLIED SIGNAL TECH SERV CORP TEAM,WHITE SANDS TEST FACIL,POB 20,LAS CRUCES,NM, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-279-6 J9 ESA SP PUBL PY 1997 VL 399 BP 523 EP 527 PG 3 WC Engineering, Aerospace; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BJ70A UT WOS:A1997BJ70A00064 ER PT B AU Olson, CF AF Olson, CF GP IEEE TI Mobile robot self-localization by iconic matching of range maps SO 8TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS, 1997 PROCEEDINGS - ICAR'97 LA English DT Proceedings Paper CT 8th International Conference on Advanced Robotics (ICAR 97) CY JUL 07-09, 1997 CL MONTEREY, CA SP ICAR, Permanent Int Comm DE mobile robot; self-localization; Hausdorff distance; iconic matching; stereo vision; Mars rover AB This paper examines techniques for a mobile robot to perform self-localization an natural terrain using stereo vision. The range map computed from a stereo image pair is first processed to generate a three-dimensional occupancy map of the terrain. This occupancy map is then compared to a similar map in a known frame of reference, The optimal relative position between the maps with respect to a Hausdorff measure is determined using efficient search techniques. These techniques allow the localization of a mobile robot to be performed robustly in natural terrain, even in the presence of noise, scene clutter, and missing data. RP Olson, CF (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MS 107-102,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4160-0 PY 1997 BP 447 EP 452 DI 10.1109/ICAR.1997.620220 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ29H UT WOS:A1997BJ29H00068 ER PT B AU Lee, S Hoffman, B Baumgartner, E Schenker, PS AF Lee, S Hoffman, B Baumgartner, E Schenker, PS GP IEEE TI GOBS: An intelligent system architecture for planetary robotic sampling SO 8TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS, 1997 PROCEEDINGS - ICAR'97 LA English DT Proceedings Paper CT 8th International Conference on Advanced Robotics (ICAR 97) CY JUL 07-09, 1997 CL MONTEREY, CA SP ICAR, Permanent Int Comm AB An architecture of intelligent robotic systems, referred to here as GOBS: Goal-Oriented Behavioral Synthesis, is presented. Connecting sensing and action in real-time, PAN automatically synthesizes goal oriented behaviors under uncertainties, errors, and faults, through task monitoring and replanning. GOBS is significant for autonomous robotic tasks in unstructured environments, including planetary robotic sampling, which require robust and fault tolerant behaviors under uncertainties and errors in sensing and actuation as well as in environmental constraints. The application of GOES to planetary robotic science is shown. RP Lee, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4160-0 PY 1997 BP 519 EP 524 DI 10.1109/ICAR.1997.620231 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ29H UT WOS:A1997BJ29H00079 ER PT B AU Fiorini, P Oboe, R AF Fiorini, P Oboe, R GP IEEE TI Internet-based telerobotics: Problems and approaches SO 8TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS, 1997 PROCEEDINGS - ICAR'97 LA English DT Proceedings Paper CT 8th International Conference on Advanced Robotics (ICAR 97) CY JUL 07-09, 1997 CL MONTEREY, CA SP ICAR, Permanent Int Comm AB This paper describes the main issues facing the development of telerobotics systems connected to the Internet. The initial hurdle relates to the definition and implementation of an appropriate communication protocol for delivering real-time data. Two of the solutions proposed in the literature are briefly summarized. Then the paper examines the issues relevant to control systems in the presence of time delay, with particular reference to telerobotic systems with force feedback. The delay introduced by Internet connections have specific characteristics that are briefly summarized, together with the control theory approaches available to design-stable algorithms. Finally, we present the results of experiments aimed at representing typical Internet connections in terms of parameters useful for the design of a control systems. RP Fiorini, P (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. OI Oboe, Roberto/0000-0003-3078-2915 NR 0 TC 8 Z9 10 U1 0 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4160-0 PY 1997 BP 765 EP 770 DI 10.1109/ICAR.1997.620268 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ29H UT WOS:A1997BJ29H00116 ER PT B AU Fijany, A Bejczy, AK AF Fijany, A Bejczy, AK GP IEEE TI A new algorithmic framework for robot dynamics analysis with application to space robots dynamics simulation SO 8TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS, 1997 PROCEEDINGS - ICAR'97 LA English DT Proceedings Paper CT 8th International Conference on Advanced Robotics (ICAR 97) CY JUL 07-09, 1997 CL MONTEREY, CA SP ICAR, Permanent Int Comm DE manipulator dynamics; dynamics simulation; space robots; parallel computation AB In this paper a new algorithm for fast serial and parallel dynamics simulation of space robots as characterized by serial chain systems with a floating base is presented. This algorithm is derived by using a recently developed algorithmic framework based on a new Schur Complement factorization of the inverse of mass matrix, M-1. The new algorithm leads to optimal serial and parallel computation for the problem, that is, an O(N) serial computation and an O(Log N) parallel computation by using O(N) processors. RP Fijany, A (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4160-0 PY 1997 BP 799 EP 805 DI 10.1109/ICAR.1997.620273 PG 7 WC Automation & Control Systems SC Automation & Control Systems GA BJ29H UT WOS:A1997BJ29H00121 ER PT B AU Chalfant, EC Bon, B Kim, WS AF Chalfant, EC Bon, B Kim, WS GP IEEE TI Experiments with an automated visual inspection system SO 8TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS, 1997 PROCEEDINGS - ICAR'97 LA English DT Proceedings Paper CT 8th International Conference on Advanced Robotics (ICAR 97) CY JUL 07-09, 1997 CL MONTEREY, CA SP ICAR, Permanent Int Comm DE vision; automated inspection; ambient light compensation; image differencing; registration AB Experiments were performed with an automated visual inspection system that detects potential flaws by comparing reference and comparison images. Three main components evaluated are: 1) image-differencing-based ambient light compensation, 2) electronic-shuttering-based ambient light rejection, and 3) image registration. The results indicate that the ambient light compensation algorithm yields 0.01% to 0.4% false flaws with lab-simulated sunlight changing from 25% to 100% intensity. Electronic shuttering with synchronized strobe lighting reduces false flaws considerably. As exposure shortens from 1/60 (fully open) to 1/1000 second, false flaws decrease 100-fold from 0.4% to 0.004%. The current registration algorithm corrects a very limited range of misregistration, correcting approximately 4 pixels of pure translational shifts over the inspection surface. A more robust image registration algorithm that can correct both translational and rotational shifts over 10 pixels misregistration would be highly desirable. RP Chalfant, EC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4160-0 PY 1997 BP 965 EP 970 DI 10.1109/ICAR.1997.620298 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BJ29H UT WOS:A1997BJ29H00146 ER PT B AU Goldin, DS AF Goldin, DS BE Teich, AH Nelson, SD McEnaney, C TI Engineering and the integration of science and technology in a competitive world SO AAAS SCIENCE AND TECHNOLOGY POLICY YEARBOOK 1998 LA English DT Proceedings Paper CT 22nd AAAS Science and Technology Policy Colloquium CY APR 23-25, 1997 CL WASHINGTON, D.C. SP Amer Assoc Adv Sci C1 NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1333 H STREET NW, WASHINGTON, DC 20005 USA BN 0-87168-611-2 PY 1997 BP 207 EP 214 PG 8 WC Public Administration SC Public Administration GA BK65T UT WOS:000072971900016 ER PT B AU Baker, E AF Baker, E GP NATL COUNCIL RALDIAT PROTECT & MEASUREMENTS TI Philosophy on astronaut protection: Perspective of an astronaut SO ACCEPTABILITY OF RISK FROM RADIATION - APPLICATION TO HUMAN SPACE FLIGHT SE NCRP SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT NCRP Symposium on Acceptability of Risk Radiation - Application to Human Space Flight CY MAY 29, 1996 CL ARLINGTON, VA SP Natl Council Radiat Protect & Measurements AB There are significant differences in the risks during the launch of a spacecraft, its journey, and its subsequent return to earth, as contrasted to the risks of latent cancers that may develop as a result of the associated radiation exposures. Once the spacecraft has landed, following a successful mission, the risks of accidental death are over. The risks of latent cancers, however, will remain with the astronauts for the rest of their lives. The same may be true for many of the effects of the space environment, including microgravity. Compounding the problem with respect to radiation are the large uncertainties accompanying the estimates of the associated latent cancer risks. In addition to radiation doses received as a result of being exposed in space, astronauts have received significant doses of radiation in conjunction with medical examinations and experiments conducted to obtain data on the effects of the space environment on humans. The experiments were considered to be a part of the ''job'' of being an astronaut, and the resulting doses were included in the medical records. Following this approach, the accompanying doses were counted against the career limits being imposed on each astronaut. As a result, volunteering for such experiments could cause an earlier termination of the career of an astronaut than would otherwise have occurred and add to the total radiation exposure, thereby increasing one's risk of subsequent illness. Through cooperative efforts, these doses have been significantly reduced in recent years. In fact, one of the outcomes of these efforts has been the incorporation of the ALARA concept into the radiation protection program for the astronauts, The fact that a space mission has a range of risks, including some that are relatively large, is no justification for failing to reduce the accompanying radiation risk. RP Baker, E (reprint author), NASA,JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATL COUNCIL RADIATION PROTECTION MEASUREMENTS PI BETHESDA PA 7910 WOODMONT AVE, SUITE 1016, BETHESDA, MD 20814 BN 0-929600-56-8 J9 NCRP SYMP PROC PY 1997 IS 3 BP 125 EP 132 PG 8 WC Engineering, Aerospace; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BJ28L UT WOS:A1997BJ28L00008 ER PT B AU Thornton, WE AF Thornton, WE GP NATL COUNCIL RALDIAT PROTECT & MEASUREMENTS TI Some comments on space flight and radiation limits SO ACCEPTABILITY OF RISK FROM RADIATION - APPLICATION TO HUMAN SPACE FLIGHT SE NCRP SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT NCRP Symposium on Acceptability of Risk Radiation - Application to Human Space Flight CY MAY 29, 1996 CL ARLINGTON, VA SP Natl Council Radiat Protect & Measurements AB Setting limits on human exposure to space-related radiation involves two very different processes-the appropriate hard science, and certain emotional aspects and expectations of the groups involved. These groups include the general public and their elected politicians, the astronauts and flight crews, and NASA managers, each group with different expectations and concerns. Public and political views of human space flight and human radiation exposures are often poorly informed and are often based on emotional reactions to current events which may be distorted by ''experts'' and the media. Career astronauts' and cosmonauts' views are much more realistic about the risks involved and there is a willingness on their part to accept increased necessary risks. However, there is concern on their part about career-threatening dose limits, the potential for overexposures, and the health effects from all sources of radiation. There is special concern over radiation from medical studies. This last concern continues to raise the question of ''voluntary'' participation in studies involving radiation exposure. There is great diversity in spaceflight crews and their expectations; and ''official'' Astronaut Office positions will reflect strong management direction. NASA management has its own priorities and concerns and this fact will be reflected in their crucial influence on radiation limits. NASA, and especially spaceflight crews, might be best sewed by exposure limits which address all sources of spaceflight radiation and all potential effects from such exposure. RP Thornton, WE (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATL COUNCIL RADIATION PROTECTION MEASUREMENTS PI BETHESDA PA 7910 WOODMONT AVE, SUITE 1016, BETHESDA, MD 20814 BN 0-929600-56-8 J9 NCRP SYMP PROC PY 1997 IS 3 BP 133 EP 140 PG 8 WC Engineering, Aerospace; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA BJ28L UT WOS:A1997BJ28L00009 ER PT B AU Zhang, SN AF Zhang, SN BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI High energy continuum spectra from X-ray Binaries SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB A variety of high energy (>1 keV) spectra have been observed in recent years from Black Hole (BH) and Neutron Star (NS) X-ray Binaries (XB). Some common physical components exist between BHXBs and NSXBs, resulting in some high energy spectral features. A common component between a BHXB and a weakly magnetized NSXB is the inner accretion disk region extending very close to the surface (for a NS) or the horizon (for a BH). The inner disk radiation can be described by a multi-color blackbody (MCB) spectral model. The surface radiation of the NS can be approximated by a Single Color Blackbody (SCB) spectrum. For a strongly magnetized NSXB, the high energy emission is from its magnetosphere, characterised by a thermal bremsstrahlung (TB) spectrum. In both BHXBs and weakly magnetized NSXBs, a hot electron cloud may exist, producing the hard X-ray power law (photon index -1.5 to -2.0) with thermal cutoff (50-200 keV). It has been recently proposed that a converging flow may be formed near the horizon of a BH, producing a softer power law (photon index about -2.5) without cutoff up to several hundred keV. Based on these concepts we also discuss possible ways to distinguish between BH and NS XBs. Finally we discuss briefly spectral state transitions in both BH and NS XBs. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Zhang, SN (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, ES-84, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 41 EP 52 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600004 ER PT B AU Meier, DL AF Meier, DL BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI A super-Eddington wind model for GRO J1655-40 SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB A model for GRO J1655-40 is' described in which the hard X/gamma-ray behavior, and long delay between the X/gamma and radio outbursts are explained by processes which occur when the accretion rate approaches and exceeds the Eddington limit. The principal feature of the model is a dense, optically thick, super-Eddington wind ejected from the center of the accretion disk. The wind is responsible for determining the luminosity and spectral evolution of the object and for suppressing the formation of a fast, relativistic jet while the accretion rate is above the Eddington limit. Our model makes use of the "magnetic switch" mechanism we recently discovered with MHD simulations of jet production in magnetized accretion disk coronae. A fast jet can be turned on (or off) by increasing (or decreasing) the Alfven velocity in the corona relative to a critical value. Examination of models of sub-and super-Eddington disks shows that V-A remains below the critical value while the wind is present, but could exceed it when the wind disappears and a hot, optically thin corona forms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 68 EP 72 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600007 ER PT B AU White, NE AF White, NE BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI X-ray observations of accretion disks SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB The properties of accretion disks in low mass X-ray binaries (LMXRB) are reviewed in the context of recent results from the ASCA observatory. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20769 USA. RP White, NE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20769 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 142 EP 151 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600014 ER PT B AU Godon, P AF Godon, P BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI Modeling tidal effects in accretion discs SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB A two-dimensional time-dependent spectral code is used for the study of tidal effects in accretion discs. A cool disc around a white dwarf (characteristic of CV systems) is modeled under the assumption of a polytropic equation of state and a standard alpha viscosity prescription. For a mass ratio q < 0.1 (considered here) and under the assumption of a reflective inner boundary, tidal effects induce an eccentric (m=l azimuthal) mode in the disc together with an elliptic (m=2 azimuthal) mode in the inner disc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Godon, P (reprint author), CALTECH, Jet Prop Lab, MS 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 335 EP 338 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600037 ER PT B AU Stapelfeldt, K Burrows, C Krist, J Watson, A AF Stapelfeldt, K Burrows, C Krist, J Watson, A CA WFPC2 Sci Team BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI WFPC2 studies of the disk and jet of HH 30 SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB Hubble Space Telescope imaging of HH 30 has revealed this object to be a prototype young stellar object (YSO) accretion disk system: An optically thick circumstellar absorption disk, 450 AU in diameter, is seen extending perpendicular to highly collimated bipolar jets. The jet width is resolved in the transverse direction and increases with distance from the central star. The size and age of the disk compare well to the early solar nebula during planet formation. HH 30 is the first YSO disk ever observed at 14 AU resolution, and the first viewed close enough to edge-on that the vertical structure of the disk is clearly visible. These HST images of HH 30 offer the first-ever opportunity to directly measure the flaring profile of an astrophysical accretion disk. We have compared the images to model nebulosities calculated in both multiple and single scattering regimes, in the latter case via chi-squared minimization. This analysis constrains the circumstellar density distribution and grain scattering properties. A brief summary of the results is presented here; full details and references appear in Burrows et al., Ap.J. (1996). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Stapelfeldt, K (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 0 TC 1 Z9 1 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 520 EP 524 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600068 ER PT B AU Angelini, L Parmar, A White, N AF Angelini, L Parmar, A White, N BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI ASCA observation of 4U1624-49 SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU AB ASCA observations of the LMXRB 4U1624-49 reveal the presence of extended emission surrounding the X-ray source probably due to a dust scattered halo. The halo spectrum can account for the low energy excess seen in the dip spectrum. C1 NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. RP Angelini, L (reprint author), NASA, Goddard Space Flight Ctr, LHEA, Code 660, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 685 EP 686 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600095 ER PT B AU Kallman, T Pereyra, NA Blondin, JM AF Kallman, T Pereyra, NA Blondin, JM BE Wickramasinghe, DT Bicknell, GV Ferrario, L TI Hydrodynamical models of line-driven accretion disk winds SO ACCRETION PHENOMENA AND RELATED OUTFLOWS: IAU COLLOQUIUM 163 SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 163 on Accretion Phenomena and Related Outflows CY JUL 15-19, 1996 CL PORT DOUGLAS, AUSTRALIA SP IAU C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kallman, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-41-4 J9 ASTR SOC P PY 1997 VL 121 BP 734 EP 735 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80B UT WOS:000073442600123 ER PT J AU Wada, BK Venneri, SL AF Wada, BK Venneri, SL TI Recent progress in adaptive structures for space SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat AB Within the past 10 years, substantial research in Adaptive Structures is evident and continues its integration into various space experiments and missions. The rapid integration is attributable to solutions Adaptive Structures potentially provides to many anticipated space challenges in large precision space structures and small spacecraft; and commercial availability of reliable actuator materials. The emphasis of the paper is on space experiments related to Adaptive Structures within the past two years. (C) 1997 International Astronautical Federation. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wada, BK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 85 EP 94 DI 10.1016/S0094-5765(97)00103-3 PG 10 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300002 ER PT J AU Hyatt, LE Rosenberg, LH AF Hyatt, LE Rosenberg, LH TI Software metrics program for risk assessment SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat AB The Software Assurance Technology Center (SATC) has developed a software metrics program consisting of goals, attributes and metrics to support the assessment of project status, risk, and product quality throughout the life cycle. The objective of the software metrics program is to assess risk areas at each phase of the development life cycle and project them into the future. The software development goals in the metrics program are evaluated by a set of attributes that help to define and classify risks. The attributes must be "measurable" by a set of metrics. These metrics must be based on data that is collectable within the confines of the software development process and must also be relevant to the quality attributes and risk assessment. This paper discusses the SATC's software risk assessment metrics program which meets these needs and is currently being applied to software developed for NASA. At each phase of the software development life cycle, attributes will be identified and metrics defined. Project data is used to demonstrate how the metric analysis was applied at that phase for risk assessment, and how that information could be used by management to manage project risks. (C) 1997 International Astronautical Federation. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Software Assurance Technol Ctr, Greenbelt, MD 20771 USA. RP Hyatt, LE (reprint author), NASA, Goddard Space Flight Ctr, Software Assurance Technol Ctr, Greenbelt, MD 20771 USA. NR 7 TC 2 Z9 2 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 223 EP 233 DI 10.1016/S0094-5765(97)00148-3 PG 11 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300017 ER PT J AU Rudd, RP Hall, JC Spradlin, GL AF Rudd, RP Hall, JC Spradlin, GL TI The Voyager Interstellar Mission SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat AB The Voyager Interstellar Mission began on January 1, 1990, with the primary objective being to characterize the interplanetary medium beyond Neptune and to search for the transition region between the interplanetary medium and the interstellar medium. At the start of this mission, the two Voyager spacecraft had already been in flight for over twelve years, having successfully returned a wealth of scientific information about the planetary systems of Jupiter, Saturn, Uranus, and Neptune, and the interplanetary medium between Earth and Neptune. The two spacecraft have the potential to continue returning science data until around the year 2020. With this extended operating lifetime, there is a high likelihood of one of the two spacecraft penetrating the termination shock and possibly the heliopause boundary, and entering interstellar space before that time. This paper describes the Voyager Interstellar Mission - the mission objectives, the spacecraft and science payload, the mission operations system used to support operations, and the mission operations strategy being used to maximize science data return even in the event of certain potential spacecraft subsystem failures. (C) 1997 International Astronautical Federation. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Rudd, RP (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 10 TC 4 Z9 4 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 383 EP 396 DI 10.1016/S0094-5765(97)00146-X PG 14 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300029 PM 11540770 ER PT J AU O'Neil, WJ Ausman, NE Gleason, JA Landano, MR Marr, JC Mitchell, RT Reichert, RJ Smith, MA AF O'Neil, WJ Ausman, NE Gleason, JA Landano, MR Marr, JC Mitchell, RT Reichert, RJ Smith, MA TI Project Galileo at Jupiter SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat AB Galileo made a highly successful arrival at Jupiter on December 7, 1995. The Galileo Atmospheric Entry Probe transmitted the first-ever direct measurements of an outer planet to the Orbiter mothership for nearly one hour while descending to a pressure depth of 23 bar-far beyond the 10 bar mission requirement. After storing the Probe data onboard, the Orbiter performed an essentially perfect insertion burn to become the first spacecraft to orbit an outer planet. In mid-March 1996, the third and final burn of Galileo's 400N main engine will raise the perijove distance so that the Orbiter can survive the radiation dose accumulation for the subsequent eleven orbits. The new flight software providing the onboard editing, compression, and telemetry capabilities required to perform the Orbiter mission via the low-gain antenna will be uplinked in May preparatory to the first satellite encounter-Ganymede 1-on June 27. The second satellite encounter-Ganymede 2-occurs on September 6. This paper will summarize: 1) the Probe mission results both engineering and scientific, 2) the problems with the Orbiter tape recorder and its recovery, 3) the Orbiter engineering operations including the loading and performance of the new flight software, and 4) early science results from the arrival and first two orbits and Ganymede encounters. Overall mission status and the forecast for the remainder of the Orbiter's two-year primary mission will also be provided. (C) 1997 Internationa Astronautical Federation. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP O'Neil, WJ (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 15 TC 0 Z9 0 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 477 EP 509 DI 10.1016/S0094-5765(97)00114-8 PG 33 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300039 ER PT J AU Palluconi, FD Albee, AL AF Palluconi, FD Albee, AL TI Mars Global Surveyor: Ready for launch in November 1996 SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat AB The Mars Global Surveyor (MGS) spacecraft wilt be launched toward Mars in November 1996. This mission is the first in the NASA Mars Surveyor Program and has been under development for the past two years. In this report the status of the MGS mission, three months prior to launch, will be described along with three specific topics: aerobraking, the lander to orbiter relay and the common operations project for the Mars Surveyor Program. The Mars Global Surveyor mission is intended to accomplish a portion of the scientific objectives of the Mars Observer Mission which was lost in 1993, three days before entering Mars orbit. To meet the established objectives a low, sun-synchronous, near circular, polar-mapping orbit is required which drives the need for aerobraking before mapping begins. MGS will carry a lander to orbiter relay capability for use with the Russian 1996 lander and small probes to be dropped to the surface of Mars by the 1998 Surveyor Mission. For the Mars Surveyor Program operation of all the landers and orbiters will be conducted under a single cost constrained Mars Surveyor Operation Project. (C) 1997 International Astronautical Federation. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Palluconi, FD (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 511 EP 516 DI 10.1016/S0094-5765(97)00115-X PG 6 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300040 ER PT J AU Kerridge, SJ Muirhead, BK Neugebauer, M Mauritz, A Tan-Wang, G Sabahi, D Green, JR Grimes, J Moura, DJP Bonneau, F Chaffaut, FX Rangeard, P Rocard, F Bibring, JP AF Kerridge, SJ Muirhead, BK Neugebauer, M Mauritz, A Tan-Wang, G Sabahi, D Green, JR Grimes, J Moura, DJP Bonneau, F Chaffaut, FX Rangeard, P Rocard, F Bibring, JP TI Champollion - Science on a comet SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 47th International-Astronautical-Federation Congress on Enlarging the Scope of Space Applications CY OCT 07-11, 1996 CL BEIJING, PEOPLES R CHINA SP Int Astronaut Federat C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kerridge, SJ (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 2 TC 4 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-APR PY 1997 VL 40 IS 2-8 BP 585 EP 595 DI 10.1016/S0094-5765(97)00136-7 PG 11 WC Engineering, Aerospace SC Engineering GA YQ446 UT WOS:000071388300048 ER PT B AU Campbell, JW Taylor, CR AF Campbell, JW Taylor, CR BE Tyson, RK Fugate, RQ TI ULTIMA free-flying large-aperture space telescope SO ADAPTIVE OPTICS AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optics and Applications CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE formation flying; large aperture space telescope AB Project ULTIMA is an investigation into the feasibility of building ultra-large aperture visible/mid-IR space telescopes. A promising concept found by the study is a freely flying spherical primary mirror, twenty meters or more in diameter, located at the L1 or L2 Earth-Sun libration point. The primary would be passively cooled to 45 K. There would be no metering structure. Instead, using a combination of alignment and steering mirrors, reaction wheels, and microthrusters, the aspherical secondary mirror, active tertiary mirror, and focal plane instruments would be precisely stationed in the correct position above the primary. The primary advanced composition would be either a membrane or ultra-light segmented technology. Preliminary findings show that a 20-30 m telescope may be feasible for imaging in the 1-20 mu m regime. RP Campbell, JW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2548-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3126 BP 200 EP 207 DI 10.1117/12.290148 PG 8 WC Optics SC Optics GA BJ86X UT WOS:A1997BJ86X00021 ER PT B AU Dekany, R Wallace, K Brack, G Oppenheimer, BR Palmer, D AF Dekany, R Wallace, K Brack, G Oppenheimer, BR Palmer, D BE Tyson, RK Fugate, RQ TI Initial test results from the Palomar 200'' Adaptive Optics System SO ADAPTIVE OPTICS AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optics and Applications CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE adaptive optics; infrared instrumentation; wavefront sensing; large telescope instrumentation AB We present laboratory subsystem test results obtained during integration of the Palomar 200'' Adaptive Optics System at Jet Propulsion Laboratory. These results pertain to the 241 actively controlled actuator, Shack-Hartmann sensed, initial delivery of a system optimized for near infrared observation with the 5 meter diameter telescope at Palomar Mountain. This system initially exploits natural guide stars. Our intention is to provide a wide-ranging summary of subsystem performance measurements and several lessons learned. Noteworthy among these results is our measurement of 6.3 +/- 0.2 electron read noise performance of our initial WFS camera, based upon a 64 x 64 pixel MIT/LL CCD detector, running at 600 kilopixel per sec per output amplifier. This camera was constructed by SciMeasure Analytical Systems, Inc. of Decatur, GA. RP Dekany, R (reprint author), SPATIAL INTERFEROMETRY SYST GRP,JET PROPULS LAB,4800 OAK GROVE BLVD,PASADENA,CA 91109, USA. NR 0 TC 18 Z9 18 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2548-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3126 BP 269 EP 276 DI 10.1117/12.290153 PG 8 WC Optics SC Optics GA BJ86X UT WOS:A1997BJ86X00029 ER PT B AU Bowman, KW Rhodes, WT AF Bowman, KW Rhodes, WT BE Tyson, RK Fugate, RQ TI Application of wavelets to wavefront reconstruction in adaptive optical systems SO ADAPTIVE OPTICS AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optics and Applications CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE adaptive optics; wavefront reconstruction; wavelets; operator compression AB One of the principle difficulties with popular wavefront reconstruction techniques such as least-squares estimators is that they are computationally intensive. In this paper a least-squares reconstructor is represented in terms of a 4-D wavelet basis. This representation is called the multiresolution wavefront reconstructor (MWR). A thresholding operation is applied to the MWR in order to remove wavelet coefficients of negligible magnitude. The resulting thresholded reconstructor matrix is sparse, leading to an estimate calculated in O(N-3) operations, as opposed to O(N-4) operations for the standard least-squares wavefront reconstructor. The thresholded multiresolution wavefront reconstructor is compared with other techniques in terms of computational complexity. RP Bowman, KW (reprint author), CALTECH,JET PROP LAB,MS 169-315,4800 OAKGROVE DR,PASADENA,CA 91106, USA. NR 0 TC 5 Z9 5 U1 0 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2548-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3126 BP 288 EP 299 DI 10.1117/12.290155 PG 12 WC Optics SC Optics GA BJ86X UT WOS:A1997BJ86X00031 ER PT B AU Campbell, JW Taylor, CR AF Campbell, JW Taylor, CR BE Tyson, RK Fugate, RQ TI Project Orion: results of a feasibility study investigating removing orbital debris using ground-based lasers and sensors SO ADAPTIVE OPTICS AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optics and Applications CY JUL 30-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE orbital debris removal AB Recent advances in adaptive optics support the feasibility of orbital debris removal by laser photoablation impulse, with laser and tracking systems located on the Earth. An in-depth systems analysis shows that individual laser pulses are most effective in lowering perigee and reducing lifetime at a zenith angle of about 40 degrees when the target is approaching the laser. Many pulses are needed to remove debris, and it is important to begin the engagement at the largest zenith angle permitted by tracking and adaptive optics. The 1-10 cm orbital debris hazard will require damage control equipment and procedures as well as on-orbit addition of shielding to the International Space Station. The current risk to satellites in low Earth-orbit is estimated to be $10-100 million per year in replacement costs. These factors suggest an international laser orbital debris removal system could be cost-effective. A demonstration in which radar and optical tracking together with adaptive optics are used to concentrate a laser on a calibrated target in orbit is the next required step in proving the feasibility and cost-effectiveness of such a system. RP Campbell, JW (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,MAIL STOP PS02,HUNTSVILLE,AL 35812, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2548-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3126 BP 614 EP 621 DI 10.1117/12.290176 PG 8 WC Optics SC Optics GA BJ86X UT WOS:A1997BJ86X00068 ER PT B AU Neeck, SP Scolese, CJ Bordi, F AF Neeck, SP Scolese, CJ Bordi, F BE Fujisada, H Calamai, G Sweeting, MN TI EOS-AM1: L-2 SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev AB EOS-AM1 is the first component of NASA's Earth Observing System (EOS). As centerpiece to Mission to Planet Earth (MTPE), EOS will provide satellite observations to determine the extent, causes, and regional consequences of global climate change. EOS-AM1 is intended to obtain information about the physical and radiative properties of clouds; air-land and air-sea exchanges of energy, carbon, and water; measurements of important trace gases in the atmosphere; and volcanology. It carries five advanced instruments: Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) provided by the Ministry of International Trade and Industry of Japan, Clouds and Earth's Radiant Energy System (CERES) provided by NASA's Langley Research Center, Multi-angle Imaging SpectroRadiometer (MISR) provided by the Jet Propulsion Laboratory, Moderate Resolution Imaging Spectroradiometer (MODIS) provided by NASA's Goddard Space Flight Center, and Measurements of Pollution in the Troposphere (MOPITT) provided by the the Canadian Space Agency. The project is currently in its D (development) Phase and is maintaining schedule for a June 1998 launch. Fabrication of Flight Model hardware is being completed and integration and subsystem testing is underway. During the next six months, all instruments will be delivered to the spacecraft contractor for integration with the spacecraft bus. System-level compatibility, performance, and environmental testing will follow. The ambitious science objectives, associated data quality and instrument/spacecraft technology considerations, and the current development status will be discussed. The EOS-AM1 project is managed by Goddard Space Flight Center. RP Neeck, SP (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 68 EP 80 DI 10.1117/12.265457 PG 13 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00007 ER PT B AU Masuoka, EJ Fleig, AJ AF Masuoka, EJ Fleig, AJ BE Fujisada, H Calamai, G Sweeting, MN TI Data systems trade studies for a next generation sensor SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE MODIS; Earth Observing System; EOSDIS; data systems AB Processing system designers must make substantial changes to accommodate current and anticipated improvements in remote sensing instruments. Increases in the spectral, radiometric and geometric resolution lead to data rates, processing loads and storage volumes which far exceed the ability of most current computer systems. To accommodate user expectations, the data must be processed and made available quickly in a convenient and easy to use form. This paper describes design trade-offs made in developing the processing system for the Moderate Resolution Imaging Spectroradiometer, MODIS, which will fly on the Earth Observing System's, AM-1 spacecraft to be launched in 1998. MODIS will have an average continuous date rate of 6.2Mbps and require processing at 6.5GFLOPS to produce 600GB of output products per day. Specific trade-offs occur in the areas of science software portability and usability of science products versus overall system performance and throughput. RP Masuoka, EJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,CODE 922,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 93 EP 104 DI 10.1117/12.265459 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00009 ER PT B AU Fleig, AJ Masuoka, EJ Yang, K AF Fleig, AJ Masuoka, EJ Yang, K BE Fujisada, H Calamai, G Sweeting, MN TI Synthetic multispectral data sets for testing remote sensing algorithms and processing systems SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE synthetic data; test data; remote sensing; algorithm development AB At the same time that we develop new sensors we also need to produce algorithms and processing systems to analyze the data in an operational mode shortly after launch. To develop and test the algorithms and processing systems we need test data. Yet new sensors are often designed to produce combinations of measurements that have never been made before. To resolve this dilemma for the Moderate Resolution Imaging Spectroradiometer (MODIS) to be launched in 1998 on the Earth Observing System (EOS) AM platform we are producing synthetic data to test the programming and operational aspects of the algorithms and processing systems. Both MODIS and the resulting synthetic data provide measurements at 36 wavelengths ranging from the visible (400 nanometers) well into the infrared (14 micrometers) day and night over the entire globe. The test data covers many of the physical conditions MODIS will observe with a full range of surface and atmospheric characteristics over land and sea with correct instrument and orbital characteristics. The data is sufficiently representational of the radiances MODIS would observe that the processing algorithms run to completion in a reasonable manner and use computing resources similar to those expected with real flight data. Although the simulation is not detailed enough to support theoretical investigations it has proven invaluable in implementing new concepts into operational code. So far we have provided hundreds of gigabytes of data covering many test cases. We describe requirements for synthetic data, tell how the data is produced, what characteristics it models, what limitations it has and what sorts of tests it supports. We show examples of the resulting data sets and describe our plans for future improvements. Sample synthetic MODIS data sets are available and we tell where and how to obtain them. RP Fleig, AJ (reprint author), UNIV MARYLAND,GODDARD SPACE FLIGHT CTR,DEPT GEOG,CODE 922,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 105 EP 112 DI 10.1117/12.265422 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00010 ER PT B AU Reuter, DC Jennings, DE McCabe, GH Travis, JW Bly, VT La, AT Nguyen, TL Jhabvala, MD Shu, PK AF Reuter, DC Jennings, DE McCabe, GH Travis, JW Bly, VT La, AT Nguyen, TL Jhabvala, MD Shu, PK BE Fujisada, H Calamai, G Sweeting, MN TI Hyperspectral sensing using the linear etalon imaging spectral array SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE imaging spectrometers; hyperspectral; remote sensing; IR arrays; IR filters; spaceflight AB The Linear Etalon Imaging Spectral Array (LEISA) represents a new class of hyperspectral cameras which use nondispersive thin film filters as wavelength selective elements. The simplicity and versatility of these instruments make them attractive for spaceflight use. LEISA currently operates in the shortwave infrared (SWIR) spectral region, but the design is adaptable to operation at wavelengths from visible to longwave IR. RP Reuter, DC (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 693,GREENBELT,MD 20771, USA. RI Jennings, Donald/D-7978-2012 NR 0 TC 3 Z9 3 U1 0 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 154 EP 161 DI 10.1117/12.265427 PG 8 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00015 ER PT B AU Bruegge, CJ Chrien, NL Gaitley, BJ Korechoff, RP AF Bruegge, CJ Chrien, NL Gaitley, BJ Korechoff, RP BE Fujisada, H Calamai, G Sweeting, MN TI Preflight performance testing of the multi-angle imaging SpectroRadiometer cameras SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev AB The Multi-angle Imaging SpectroRadiometer (MISR) will provide global data sets from Earth orbit using nine pushbroom cameras, each viewing in a fixed, unique direction. Data will be acquired for day-lit portions of the orbit at an average rate of 3.3 Mbits s(-1) for the entire six year mission. Automated ground processing will make use of the instrument radiometric, spectral, and geometric calibrations, to produce registered images at the nine view angles. This, the Level 1 product, provides top-of-atmosphere scene radiances, weighted by the spectral band profile for the instrument. Initially, processing will proceed with preflight determined radiometric response coefficients. In-flight radiometric calibration of the sensor will then provide monthly updates to these coefficients, to account for degradation which may occur during the mission. The spectral response profiles are invariant in time, and are provided only by the preflight measurements. These include an out-of-band spectral calibration of each channel. These spectral data are used as input to the radiometric calibration of the instrument, and also to produce certain Level 2 products for which an out-of-band correction is made. This paper describes the calibration program, with emphasis on results from the recently completed preflight calibration. RP Bruegge, CJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 244 EP 255 DI 10.1117/12.265439 PG 12 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00026 ER PT B AU Barnes, WL Barnes, RA Holmes, AW AF Barnes, WL Barnes, RA Holmes, AW BE Fujisada, H Calamai, G Sweeting, MN TI Characterization and calibration results from the visible and infrared scanner (VIRS) for the tropical rainfall measuring mission (TRMM) SO ADVANCED AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced and Next-Generation Satellites II CY SEP 23-26, 1996 CL TAORMINA, ITALY SP CNR, Ctr Natl Etud Spatiales, City Taormina, Univ Catania, Dept Bot, Italian Assoc Remote Sensing, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE TRMM; VIRS; space sensor; radiometer; visible; infrared; calibration; characterization AB The visible and infrared scanner (VIRS), one of three primary sensors on the Tropical Rainfall Measuring Mission (TRMM), has completed its development and test phase at Santa Barbara Remote Sensing and has been delivered to the Goddard Space Flight Center where it has been integrated on the TRMM spacecraft. VIRS is a five band imaging radiometer with bandpasses similar to those of the Advanced Very High Resolution Radiometers (AVHRR's) that have flown on the NOAA series of satellites for the last 18 years. VIRS will scan a +/-45 degree swath with a 2.11 kilometer IFOV at nadir from the non-sun-synchronous 350 kilometer TRMM orbit. All five bands will be cooled to 107K at mission start using a passive radiative cooler. The two reflected solar bands will be calibrated on orbit using a solar diffuser. This paper discusses ground calibration and characterization results and proposed post-launch radiometric calibration procedures for the VIRS data. RP Barnes, WL (reprint author), NASA,GODDARD SPACE FLIGHT CTR,MS 970,GREENBELT,MD 20771, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2361-0 J9 P SOC PHOTO-OPT INS PY 1997 VL 2957 BP 266 EP 276 DI 10.1117/12.265441 PG 11 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BH14W UT WOS:A1997BH14W00028 ER PT J AU Volpe, R Balaram, J Ohm, T Ivlev, R AF Volpe, R Balaram, J Ohm, T Ivlev, R TI Rocky 7: a next generation Mars rover prototype SO ADVANCED ROBOTICS LA English DT Article; Proceedings Paper CT 1996 IEEE/RSJ International Conference on Intelligent Robots and Systems - Robotic Intelligence Interacting with Dynamic Worlds (IROS 96) CY NOV 04-08, 1996 CL SENRI LIFE SCI CTR, OSAKA, JAPAN SP IEEE Ind Electr Soc, IEEE Robot & Automat Soc, Robot Soc Japan, Soc Instrument & Control Engineers, New Technol Fdn HO SENRI LIFE SCI CTR AB This paper provides a system overview of a new Mars rover prototype, Rocky 7. We describe all system aspects: mechanical and electrical design, computer and software infrastructure, algorithms for navigation and manipulation, science data acquisition, and outdoor rover testing. In each area, the improved or added functionality is explained in a context of its path to flight and within the constraints of desired science missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Volpe, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 31 Z9 34 U1 0 U2 1 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-1864 J9 ADV ROBOTICS JI Adv. Robot. PY 1997 VL 11 IS 4 BP 341 EP 358 PG 18 WC Robotics SC Robotics GA YP154 UT WOS:000071248100004 ER PT S AU Stoica, A Blosiu, J AF Stoica, A Blosiu, J BE Morabito, FC TI Neural learning using orthogonal arrays SO ADVANCES IN INTELLIGENT SYSTEMS SE FRONTIERS IN ARTIFICIAL INTELLIGENCE AND APPLICATIONS LA English DT Proceedings Paper CT AMSE-ISIS 97 Symposium on Intelligent Systems CY 1997 CL REGGIO CALABRIA, ITALY SP Int Assoc Adv Modelling & Simulat, France, Adv & Appl Technol Inst Fdn, Switzerland, European Assoc Econ & Management, Spain, Balkan Union FS & AI, Romania, Consorzio Ric Energia & Applicaz Tecnol Elettromagnetismo, Italy, European Lab Intelligent Tech Engn, Germany, Fuzzy Log Syst Inst, Japan, Int Assoc Fuzzy Set Management & Econ, Spain, Univ Reggio Calabria, IEEE Neural Network Council, Italian Chapter, Ist Int Alti Studi Sci, INNS SIG, Soc Italiana Reti Neuroniche, Assoc Elettrotec & Elettron Italiana, Comune Reggio Calabria, Univ Reggio Calabria, Dipt Ingegneria elettron & Mat Applicata, ELSAG Bailey, Fondaz Bonino Pulejo, Prov Regio Calabria, Reg Calabria, Univ Reggio Calabria, Fac Ingegneria AB The paper proposes the use of the orthogonal arrays for neural network learning. Leaning caa be seen as a search for the neural weights that give an optimal network performance. The search/optimization adopted here is inspired from Taguchi methods based on Orthogonal Arrays (a special set of Latin Squares), which proved to be a powerful tool in robust design. In its most straightforward implementation the search requires only a few steps, leading to fast neural learning. However, the solution obtained in this way is only in the vicinity of an optimum. Getting closer to the optimum can be done by making the search adaptive, at the price of an increased number of iterations. RP Stoica, A (reprint author), CALTECH,JET PROP LAB,CTR SPACE MICROELECT TECHNOL,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I O S PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0922-6389 BN 90-5199-355-2 J9 FR ART INT PY 1997 VL 41 BP 418 EP 423 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BJ94K UT WOS:A1997BJ94K00067 ER PT B AU Kim, MS Mulchi, CL Daughtry, CST Chappelle, EW McMurtrey, JE Corp, LA AF Kim, MS Mulchi, CL Daughtry, CST Chappelle, EW McMurtrey, JE Corp, LA BE Narayanan, RM Kalshoven, JE TI Fluorescence images of soybean leaves grown under increased O-3 and CO2 SO ADVANCES IN LASER REMOTE SENSING FOR TERRESTRIAL AND OCEANOGRAPHIC APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advances in Laser Remote Sensing for Terrestrial and Oceanographic Applications CY APR 21-22, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE fluorescence; O-3 stress; elevated CO2; open-top chamber system; photosynthetic efficiency AB Fluorescence imaging system (FIS) developed in our laboratories was used to study steady state fluorescence characteristics of plants subjected to chronic ozone stress. The imaging system consisted of four ultraviolet (UV) fluorescent lamps as an excitation source, an automated filter wheel with band pass filters, and a cooled charge coupled device (CCD) camera. Fluorescence images were captured at blue (F450), green (F550), red (F680), and far-red (F740) region of the spectrum centered at 450 nm, 550 nm, 680 nm, and 740 nm, respectively, Four different concentration schemes of tropospheric O-3 and CO2 interactive environments were considered for this investigation. Soybean plants were grown full-season in 3 m diameter open-top chambers (OTC's) purged with the following gaseous treatments: charcoal filtered (CF) air; CF + CO2; nonfiltered (NF) air + O-3; and NF + O-3 + CO2. Cultivars 'Forrest' (O-3 sensitive) and 'Essex' (O-3 tolerant) were planted in each chamber treatment. The mean seasonal (7 h/day) CO2 and O-3 concentrations monitored for these treatments were: 331 mu l/l CO2 and 22 nl/l O-2. 472 mu l/l CO2 and 21 nl/l O-3; 327 mu l/l CO2 and 63 nl/l O-3; and 479 mu l/l CO2 and 64 nl/l O-3, respectively. The most pronounced differences among the treatments were noted in the F450 and F550 images of leaves in both cultivars exposed to elevated O-3 with more pronounced irregular appearances (white spots) in the O-3 sensitive cultivar. Changes in cellular membrane integrity caused by chronic exposure to elevated O-3 may have attributed to the increase in F450 and F550 intensities observed on the leaves grown in the elevated O-3 environment. Significantly higher F680 and F740 fluorescence image intensities were observed in the elevated O-3 exposed leaves in the presence and in the absence of elevated CO2 in both soybean cultivars. These observations suggested that elevated O-2 affected the photosynthetic efficiency of the plants even in the environment with elevated CO2. The O-3 sensitive 'Forrest' was found to have higher fluorescence intensities in all four bands compared to those of the more O-3 tolerant 'Essex'. Although visible stress symptoms such as chlorosis, discoloration, or necrosis were not evident in the leaves used in this study, FIS demonstrated the capability of detecting the effects of chronic exposures to different air quality treatments. The OTC system air treatment environments in conjunction with FIS enhanced our understanding of the interactions between plant stresses and fluorescence responses. These findings with FIS represent a new approach in the studies of plant-pollutant interactions by providing a rapid nondestructive assessment. RP Kim, MS (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771, USA. NR 0 TC 5 Z9 5 U1 1 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2474-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3059 BP 22 EP 31 DI 10.1117/12.277615 PG 10 WC Oceanography; Remote Sensing; Optics SC Oceanography; Remote Sensing; Optics GA BJ21X UT WOS:A1997BJ21X00003 ER PT B AU Corp, LA McMurtrey, JE Kim, MS Daughtry, CST Chappelle, EW Mulchi, CL AF Corp, LA McMurtrey, JE Kim, MS Daughtry, CST Chappelle, EW Mulchi, CL BE Narayanan, RM Kalshoven, JE TI Physical properties of leaf level fluorescence SO ADVANCES IN LASER REMOTE SENSING FOR TERRESTRIAL AND OCEANOGRAPHIC APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advances in Laser Remote Sensing for Terrestrial and Oceanographic Applications CY APR 21-22, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE fluorescence; plant stress; remote sensing; UV transmission AB Green vegetation when excited by specific wavelengths of light dissipates a portion of the absorbed energy as light emissions in the form of fluorescence. Fluorescence emissions from vegetation occur in five primary regions of the spectrum, namely; ultraviolet (UV), blue, green, red, and far-red(FR). Many investigators have demonstrated relationships between these fluorescence intensities and ratios of these intensities to various forms of plant stress. The observed fluorescence from plant constituents varies with concentration and location within the leaf due to the interactions of diffused fluorescence with the optical properties (ie. absorption and transmission characteristics) of neighboring compounds. Recently there has been considerable debate as to the extent UV excitation sources penetrate the leaf and to what regions of the leaf can the majority of these in vivo fluorescence emissions be attributed. The deeper a compound is located within the leaf the lower the probability that fluorescence emissions will be received from this compound due to decreases in the quanta of excitation energy and increases in the probability that the fluorescence emission will be reabsorbed, These studies demonstrated that a portion of the fluorescence excitation radiation at 280 nm (4.5 W/m(2) at the leafs surface) was transmitted through both field grown corn (Zea mays L.) and soybean (Glycine max Merr.). Furthermore, UV transmittance increased toward longer wavelengths leading to an increased quanta UV light exciting a higher percentage of compounds located throughout the mesophyll and bundle sheath layers of the leaf. Significant amounts of fluorescence were observed in the green and far-red bands at the abaxial (bottom) surface of the leaf with adaxial (top) surface excitation, while fluorescence emissions in the UV, blue, and red bands were to a large extent reabsorbed. Leaf transmittance is relatively high in the green and far-red regions of the spectrum giving rise to these emissions at the bottom surface. In addition, both UV and blue fluorescence emissions were observed from the leaf epidermis and quantified to 15 % of the blue band fluorescence and up to 30 % of the UV band fluorescence emanating from the intact leaf. RP Corp, LA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 1 U2 4 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2474-9 J9 P SOC PHOTO-OPT INS PY 1997 VL 3059 BP 32 EP 40 DI 10.1117/12.277616 PG 9 WC Oceanography; Remote Sensing; Optics SC Oceanography; Remote Sensing; Optics GA BJ21X UT WOS:A1997BJ21X00004 ER PT S AU Baram, Y AF Baram, Y BE Mozer, MC Jordan, MI Petsche, T TI Consistent classification, firm and soft SO ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 9: PROCEEDINGS OF THE 1996 CONFERENCE SE ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS LA English DT Proceedings Paper CT 10th Annual Conference on Neural Information Processing Systems (NIPS) CY DEC 02-05, 1996 CL DENVER, CO SP NIPS Fdn AB A classifier is called consistent with respect to a given set of class-labeled points if it correctly classifies the set. We consider classifiers defined by unions of local separators and propose algorithms for consistent classifier reduction. The expected complexities of the proposed algorithms are derived along with the expected classifier sizes. In particular, the proposed approach yields a consistent reduction of the nearest neighbor classifier, which performs ''firm'' classification, assigning each new object to a class, regardless of the data structure. The proposed reduction method suggests a notion of ''soft'' classification, allowing for indecision with respect to objects which are insufficiently or ambiguously supported by the data. The performances of the proposed classifiers in predicting stock behavior are compared to that achieved by the nearest neighbor method. C1 TECHNION ISRAEL INST TECHNOL,DEPT COMP SCI,IL-32000 HAIFA,ISRAEL. RP Baram, Y (reprint author), NASA,AMES RES CTR,NATL RES COUNCIL,MS 210-9,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 SN 1049-5258 BN 0-262-10065-7 J9 ADV NEUR IN PY 1997 VL 9 BP 326 EP 332 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA BH93C UT WOS:A1997BH93C00046 ER PT J AU Smith, RD AF Smith, RD TI Roll over, red cover SO AEROSPACE ENGINEERING LA English DT Article C1 CALTECH,JET PROP LAB,PASADENA,CA 91125. RP Smith, RD (reprint author), WYLE LABS INC,HUNTSVILLE,AL, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SOC AUTOMOTIVE ENG INC PI WARRENDALE PA 400 COMMONWEALTH DRIVE, WARRENDALE, PA 15096 SN 0736-2536 J9 AEROSPACE ENG JI Aerosp. Eng. PD JAN-FEB PY 1997 VL 17 IS 1-2 BP 24 EP 27 PG 4 WC Engineering, Aerospace SC Engineering GA WD958 UT WOS:A1997WD95800027 ER PT J AU LoSeen, D Chehbouni, A Njoku, E Saatchi, S Mougin, E Monteny, G AF LoSeen, D Chehbouni, A Njoku, E Saatchi, S Mougin, E Monteny, G TI An approach to couple vegetation functioning and soil-vegetation-atmosphere-transfer models for semiarid grasslands during the HAPEX-Sahel experiment SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article ID GROUND SURFACE-TEMPERATURE; ENERGY-TRANSPORT; EVAPORATION; PARAMETERIZATION; MOISTURE; EVAPOTRANSPIRATION; RESISTANCES; CLIMATE; LAYER AB This paper presents a model which has been developed to simulate the major land surface processes occurring in arid and semiarid grasslands. The model is composed of a hydrological submodel which describes the water and energy budgets, and a vegetation growth submodel which groups the processes associated with biomass production, Emphasis has been placed on developing a realistic representation of the interaction between these subprocesses taking account of the different time scales involved. The hydrological submodel couples the energy balance of the soil/canopy with the soil moisture and thermal dynamics. It interacts with the vegetation growth submodel by exchanging information needed to account for the influence of plant water status and canopy temperature on photosynthesis, and the influence of the vegetation canopy on the boundary layer within which transport processes are taking place. The model has been tested with meteorological, biomass and energy flux measurements made on a grassland site during the HAPEX-Sahel experiment, Niger, in 1992. Model simulations of biomass over the growing season are all found to be within a 15% error margin allowed on biomass measurements, Hourly values of net radiation, as well as latent and sensible heat fluxes, are simulated with an RMSE of less than 50 W m(-2). Given the relative simplicity of the model and the long period of uninterrupted simulation, these results are considered satisfactory, Overall, the results show that the model behaves consistently at different stages of vegetation growth, and satisfactorily reproduces the interdependence of vegetation growth with the physical processes giving rise to the water and energy balances. C1 CALTECH,JET PROP LAB,PASADENA,CA 91109. ORSTOM,HYDROL LAB,F-34032 MONTPELLIER,FRANCE. CNES,CESBIO,F-3105 TOULOUSE,FRANCE. RI Lo Seen, Danny/C-2679-2008 OI Lo Seen, Danny/0000-0002-7773-2109 NR 30 TC 18 Z9 18 U1 0 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD JAN PY 1997 VL 83 IS 1-2 BP 49 EP 74 DI 10.1016/S0168-1923(96)02350-7 PG 26 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA WC275 UT WOS:A1997WC27500004 ER PT J AU Gerhold, CH AF Gerhold, CH TI Active control of fan-generated tone noise SO AIAA JOURNAL LA English DT Article AB An experiment to control the noise radiated from the inlet of a ducted fan using a time domain active adaptive system is reported on. The control sound source consists of loudspeakers arranged in a ring around the fan duct, The error sensor location is in the fan duct. The purpose of this experiment is to demonstrate that the in-duct error sensor reduces the mode spillover in the far field, thereby increasing the efficiency of the control system. The control system is found to reduce the blade passage frequency tone significantly in the acoustic far field when the mode orders of the noise source and of the control source are the same, when the dominant wave in the duct is a plane wave. The presence of higher order modes in the duct reduces the noise reduction efficiency, particularly near the mode cut on where the standing wave component is strong, but the control system converges stably. The control system is also found to be stable and convergent when the first circumferential mode is generated in the duct both by the fan and by the control source, The control system is found to reduce the fan noise in the far field on an are around the fan inlet by as much as 20 dB with none of the sound amplification associated with mode spillover. RP Gerhold, CH (reprint author), NASA,LANGLEY RES CTR,AEROACOUST BRANCH,FLUID MECH & ACOUST DIV,MS 461,HAMPTON,VA 23681, USA. NR 16 TC 7 Z9 7 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 JAN PY 1997 VL 35 IS 1 BP 17 EP 22 PG 6 WC Engineering, Aerospace SC Engineering GA WB040 UT WOS:A1997WB04000003 ER PT J AU Blanchard, AE Lachowicz, JT Wilkinson, SP AF Blanchard, AE Lachowicz, JT Wilkinson, SP TI NASA Langley Mach 6 quiet wind-tunnel performance SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 34th Aerospace Sciences Meeting and Exhibit CY JAN 15-19, 1996 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB The Bow in the NASA Langley Mach 6 quiet wind tunnel has been investigated to quantify the effectiveness of laminar-flow control techniques used to delay transition of the nozzle-wall boundary layer, The results of this investigation include an assessment of the mean and unsteady nozzle flow to define the quiet core length, and hence performance, over the operating range of the facility, A large, uniform region of Mach 5.91 flow was documented for a variety of unit Reynolds numbers. By using a prototype constant-voltage anemometer to measure the unsteady flowfield, acoustic radiation patterns from the transitional nozzle wall boundary layers were mapped, These disturbances originating at the irregular edge of the transitional nozzle-wall boundary layer were shown to follow Mach lines into the test section of the nozzle, thereby limiting the length of the quiet core, With a virtual origin downstream of the nozzle throat, a Reynolds number dependency was found for the amplitudes of the acoustic radiation, The spectral evolution of noisy Bow in the quiet tunnel was shown, and measurable freestream disturbances, outside the region of quiet flow, were found to be qualitatively similar to those documented for conventional high-speed tunnels. In sum, the laminar-flow control techniques used to delay nozzle-wall boundary layer transition in the Mach 6 nozzle test chamber facility have succeeded in producing a substantial region of quiet flow suitable for high-speed boundary layer stability research. C1 N CAROLINA STATE UNIV,DEPT MECH & AEROSP ENGN,RALEIGH,NC 27695. NASA,LANGLEY RES CTR,FLOW MODELING & CONTROL BRANCH,HAMPTON,VA 23681. RP Blanchard, AE (reprint author), OLD DOMINION UNIV,DEPT MECH ENGN,NORFOLK,VA 23529, USA. NR 23 TC 21 Z9 21 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 1997 VL 35 IS 1 BP 23 EP 28 DI 10.2514/2.82 PG 6 WC Engineering, Aerospace SC Engineering GA WB040 UT WOS:A1997WB04000004 ER PT B AU Smith, JA Pedelty, JA AF Smith, JA Pedelty, JA BE Iverson, AE Shen, SS TI Combined hyperspectral and thermal imaging for improved land surface flux estimation SO ALGORITHMS FOR MULTISPECTRAL AND HYPERSPECTRAL IMAGERY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral and Hyperspectral Imagery III CY APR 22-23, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE neural networks; mixture analysis; environmental assessment; AVIRIS; thermal infrared AB We present a new approach for estimating land surface fluxes using remote sensing optical and thermal infrared observations. We employ an artificial neural network and train it with a radiosity reflectance model. We then apply the network without retraining to extract geometrical view factors from AVIRIS imagery. We use the retrieved view factors and in-situ meteorological data to drive a surface energy balance model. Theoretical directional view factors were retrieved with an average absolute error of 15%. Hemispherical view factors were retrieved. with a root mean square error of 6%. Surface net radiation estimated using the AVIRIS imagery and the surface energy balance model varied from 520 W m(-2) to 650 W m(-2) and are consistent with tower measurements, The retrieved view factors may also be used to model mixed pixel response for directional thermal infrared data. RP Smith, JA (reprint author), NASA,GODDARD SPACE FLIGHT CTR,TERR PHYS LAB,CODE 920,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2486-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3071 BP 120 EP 127 DI 10.1117/12.280588 PG 8 WC Remote Sensing; Optics SC Remote Sensing; Optics GA BJ39C UT WOS:A1997BJ39C00011 ER PT J AU SantaMaria, OL Mueller, AW Conner, DA AF SantaMaria, OL Mueller, AW Conner, DA GP AMER HELICOPTER SOC TI Acoustics of UH-60 black hawk with growth rotor blades SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB Acoustic data were acquired during a flight test in 1995 of a UH-60L Black Hawk equipped with Growth Rotor Blades (GRB) performing terminal area operations. Limited acoustic data from the same aircraft equipped with Standard Rotor Blades (SRB) were also acquired. These data were analyzed and compared with data from a 1993 flight test of a UH-GOA aircraft to assess differences in acoustics characteristics between the two types of blades. This paper presents dBA and Sound Exposure Level (SEL) acoustic data from level flight and approach conditions for the GRB, and the SRB, both from this test and the earlier, 1993 test. An expected increase in levels with increase in air speed of the GRB-equipped aircraft was observed in both level flight and approach. Comparisons between the GRB and the SRB data from the same 1995 test show no acoustic improvement in level flight, but a significant improvement in approach for the helicopter equipped with the GRB. Comparisons between GRB data from the 1993 test and SRB data the 1995 test show similar results. RP SantaMaria, OL (reprint author), NASA,LANGLEY RES CTR,AEROACOUST BRANCH,FLUID MECH & ACOUST DIV,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 12 EP 22 PG 11 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00002 ER PT J AU Light, JS AF Light, JS GP AMER HELICOPTER SOC TI Results from an XV-15 rotor test in the national full-scale aerodynamics complex SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB A full-scale, single XV-15 rotor was tested in the National Full-Scale Aerodynamics Complex (NFAC) 80-by 120-Foot Wind Tunnel at NASA Ames Research Center. Performance and loads measurements were obtained for hover and helicopter-mode forward flight. The hover performance agrees reasonably well with previously measured XV-15 isolated rotor performance. Performance and loads were measured for tunnel speeds from 60 to 80 knots, and for rotor tip-path-plane angles from -15 deg to +15 deg. Comparisons are made with previous wind tunnel and flight test data for the full-scale XV-15. Time histories of blade bending moments show good correlation between wind tunnel and flight test. RP Light, JS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 231 EP 239 PG 9 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00021 ER PT B AU Brentner, KS Farassat, F AF Brentner, KS Farassat, F GP AMER HELICOPTER SOC TI An analytical comparison of the acoustic analogy and Kirchhoff formulation for moving surfaces SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB The Lighthill acoustic analogy, as embodied in the Ffowcs Williams-Hawkings (FW-H) equation, is compared with the Kirchhoff formulation for moving surfaces. A comparison of the two governing equations reveals that the main Kirchhoff advantage (namely nonlinear flow effects are included in the surface integration) is also available to the FW-H method if the integration surface used in the FW-H equation is not assumed impenetrable. The FW-H equation is analytically superior for aeroacoustics because it is based upon the conservation laws of fluid mechanics rather than the wave equation. This means that the FW-H equation is valid even if the integration surface is in the nonlinear region. This is demonstrated numerically in the paper. The Kirchhoff approach can lead to substantial errors if the integration surface is not positioned in the linear region. These errors may be hard to identify. Finally, new metrics based On the Sobolev norm are introduced which may be used to compare input data for both quadrupole noise calculations and Kirchhoff noise predictions. RP Brentner, KS (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 687 EP 696 PG 10 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00057 ER PT J AU Fletcher, KS Decker, WA Matuska, DG Morris, PM Smith, MT AF Fletcher, KS Decker, WA Matuska, DG Morris, PM Smith, MT GP AMER HELICOPTER SOC TI VMS simulation of a variable diameter tiltrotor SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB A joint NASA/Sikorsky simulation study was performed in the NASA Ames Vertical Motion Simulator to evaluate the performance and handling qualities of a Variable Diameter Tiltrotor (VDTR) compared to a Fixed Diameter Tiltrotor (FDTR) during normal and emergency terminal area operations. Pilots from the FAA, NASA, academia, and industry evaluated both the VDTR and FDTR during one-engine inoperative take-offs and approaches and all-engine inoperative landings. The simulation math model was based on NASA's preliminary design version of the Generic Tiltrotor Simulation code. Both fixed and variable diameter rotor versions exhibited Level One handling qualities during normal maneuvers with both engines operating. In general, the VDTR had a greater power margin and performance in helicopter mode resulting from a lower disk loading requiring 20 to 25% less power at similar thrust levels. This was an advantage during one-engine and all-engine inoperative procedures. This simulation study quantified the performance merits of the VDTR concept and demonstrated that the VDTR offers enhanced performance and terminal area safety for future civil tiltrotor transports. The simulation was also beneficial in identifying areas for further investigation for the VDTR and basic civil tiltrotor concepts. RP Fletcher, KS (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 939 EP 957 PG 19 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00079 ER PT B AU Chung, WW Schroeder, JA AF Chung, WW Schroeder, JA GP AMER HELICOPTER SOC TI Visual and roll-lateral motion cueing synchronization requirements for motion-based flight simulations SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB An investigation of flight simulation cueing synchronization requirements for the visual, roll motion, and lateral motion was conducted on the Vertical Motion Simulator (VMS) at NASA Ames Research Center. The unique displacement capability of the VMS was exploited by developing a piloted task such that the visual and motion cues matched closely for a baseline configuration. Pilots performed a lateral sidestep between two points 20 feet apart using a helicopter model designed to have satisfactory handling qualities. Since the VMS has in excess of 20 feet lateral travel, the task was simulated exactly. That is, the motion and visual cues had a one-to-one correspondence. Starting with the baseline simulation cueing configuration that had synchronous visual, roll, and lateral cues, time delays of 40 and 80 msec were introduced into the visual, roll, and lateral axes in a randomized matrix giving a total of 27 configurations. The baseline configuration was developed based on the current FAA helicopter simulator specifications for civil helicopter motion fidelity requirements, which has little objective data for its support. Six experienced test pilots from both government and industry rated all of the configurations. Objective and subjective data were taken that included handling qualities ratings, motion fidelity ratings, and perceptions of synchronization. Initial analysis of the data indicate support for aspects of the current FAA specifications on civil helicopter motion fidelity requirements, with some additional preconditions. Based upon a statistical analysis of the data, recommendations are made for permissible cueing delays and asynchronization. RP Chung, WW (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 994 EP 1006 PG 13 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00083 ER PT J AU Schroeder, JA Chung, WW AF Schroeder, JA Chung, WW GP AMER HELICOPTER SOC TI Effects of roll and lateral flight simulation motion gains on a sidestep task SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB To represent coordinated maneuvers accurately in a ground-based flight simulator, the motion platform must translate laterally when it rolls. Typical platform lateral displacement limits often prevent an accurate representation of such maneuvers. The result is that the pilot receives an uncoordinated lateral specific force (ball not centered) when the model is not calculating one. This study examined the effects of these false uncoordinated roll-lateral motion cues when using a coordinated math model. The vehicle model represented a typical helicopter with satisfactory handling qualities in the roll-lateral axes. The task was a two-degree-of-freedom sidestep, in which the pilot controlled lateral position through roll attitude. Two gains varied in the motion platform control. One gain controlled the ratio between platform roll angle and math model (and thus visual) roll angle. The other gain controlled the amount of lateral platform movement, relative to the amount needed, to keep the apparent gravity vector aligned vertically about the pilot. Both gains varied from zero to one. With both gains equal to one, pilots evaluated the true 1:1 motion case, in which the motion cues matched the visual cues. As the motion cues degraded, both objective and subjective evaluations worsened. Pilot opinions of motion fidelity reasonably matched a combination of criteria developed previously. RP Schroeder, JA (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 1007 EP 1015 PG 9 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00084 ER PT J AU Moulton, MA Bridgeman, JO Caradonna, FX AF Moulton, MA Bridgeman, JO Caradonna, FX GP AMER HELICOPTER SOC TI Development of an overset/hybrid CFD method for the prediction of hovering performance SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB This paper concerns the development of a new overset/hybrid code. The method combines an overset version of the well-known HELIX-I code with the TURNS Navier-Stokes code. The TURNS code provides the surface viscous flow while HELIX-I provides accurate wake convection for the prediction of the induced power. The method is grid point efficient since the Eulerian solver is not burdened with resolving the shed wake. Initial computations of hybrid and overset versions of HELIX-I were performed and compared to hovering rotor data. Using a hybrid method, performance predictions of the AH-64A rotor demonstrate a new ability to predict hovering flows into the stall regime. Application of the combined hybrid/overset procedure to the UH-60A rotor provide the first. validation of this new method. RP Moulton, MA (reprint author), NASA,AMES RES CTR,FLOW ANAL INC,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 1088 EP 1101 PG 14 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00089 ER PT B AU Kottapalli, S AF Kottapalli, S GP AMER HELICOPTER SOC TI Identification and control of rotorcraft hub loads using neural networks SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB The objective of the study was to develop a robust neural network based controller to minimize vibratory hub loads. A metric consisting of five vibratory hub load components (with their sine and cosine components) obtained from a wind tunnel test of a four-bladed rotor with individual blade control was used to characterize the hub loads. The neural network control procedure was bound by the following ground rules: the controller must converge quickly in six iterations or less and gradient based optimization techniques must not be used. A simple and straightforward iterative procedure for neural control was applied. Two neural networks were used in the procedure requiring a plant model (using a radial-basis function neural network) and an ''inverted neural network for control'' model (using a back-propagation neural network). A simple half-interval calculation which halves the metric was used in order to speed up convergence. The neural network control procedure successfully achieved the objective within the given constraints. Finally, a limited-scope comparison of the results from the present neural control procedure with those from a one-step deterministic controller showed that the two control methods were roughly comparable, with neural control being slightly more robust. RP Kottapalli, S (reprint author), NASA,AMES RES CTR,ROTORCRAFT AEROMECH BRANCH,MOFFETT FIELD,CA 94035, USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 1387 EP 1406 PG 20 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00113 ER PT J AU Fletcher, JW Tischler, MB AF Fletcher, JW Tischler, MB GP AMER HELICOPTER SOC TI Improving helicopter flight mechanics models with laser measurements of blade flapping SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB A high fidelity linear model of the UH-60 helicopter flight dynamics at hover is developed using a combination of system identification and component-type simulation modeling techniques. The results are enhanced through the use of a new flight test database generated with the NASA/Army RASCAL JUH-60A helicopter which includes dynamic response data for the main-rotor blade motions in addition to those of the aircraft fuselage and drive train. Very high quality measurements of the main rotor blade motions are obtained using a new measurement method which employs hub-mounted laser distance transducers. The flight test data are first used to optimize a component-type flight mechanics simulation model of the UH-60 for hover. Correlation of the off-axis responses of the model with the flight data is shown to be greatly improved when an empirical aerodynamic phase lag correction is included in the main rotor aerodynamic model formulation. The updated simulation model is then used to refine the model structure used for a parametric system identification study. A 16 degree-of-freedom linear model is identified using the refined model structure and the laser flapping data. The model is valid over a frequency range of 0.5 to 40 rad/sec for the hover flight condition. Previously unidentifiable parameters are determined through use of the new flight data and refined model structure, and excellent identification of the off-axis response characteristics of the aircraft is achieved. The identified primary rotor flapping parameters agree well with theoretical values and provide a high level of confidence in the newly identified model. RP Fletcher, JW (reprint author), USA,ATCOM,CTR DEV & ENGN,AVIAT RES,AMES RES CTR,AEROFLIGHTDYNAM DIRECTORAT,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 1467 EP 1494 PG 28 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00118 ER PT J AU Wilson, SB Gelhausen, PA Wilson, CM AF Wilson, SB Gelhausen, PA Wilson, CM GP AMER HELICOPTER SOC TI STOVL propulsion system selections effect on aircraft design SO AMERICAN HELICOPTER SOCIETY - 53RD ANNUAL FORUM PROCEEDINGS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 53rd Annual Forum of the American-Helicopter-Society CY APR 29-MAY 01, 1997 CL VIRGINIA BEACH, VA SP Amer Helicopter Soc AB This paper examines the effect of vertical landing propulsion system decisions on the optimum design for a multimission STOVL (short take-off and vertical landing) Strike Fighter aircraft. Advances in propulsion have opened the design space for STOVL aircraft. The optimum design is dependent on the propulsion system selected for vertical operations. Unlike past studies the primary engine can be sized by up-and-away aircraft performance rather than vertical landing operations for the three different STOVL propulsion systems examined. RP Wilson, SB (reprint author), NASA,AMES JSF PROGRAM OFF,ARLINGTON,VA, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HELICOPTER SOCIETY PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314-2538 PY 1997 BP 1627 EP 1633 PG 7 WC Engineering, Aerospace SC Engineering GA BH89P UT WOS:A1997BH89P00132 ER PT J AU Lane, HW Gretebeck, RJ Schoeller, DA DavisStreet, J Socki, RA Gibson, EK AF Lane, HW Gretebeck, RJ Schoeller, DA DavisStreet, J Socki, RA Gibson, EK TI Comparison of ground-based and space flight energy expenditure and water turnover in middle-aged healthy male US astronauts SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Article DE energy expenditure; space flight; doubly labeled water; dietary intakes ID DOUBLY LABELED WATER; YOUNG-ADULT MEN; LEAN BODY-MASS; BED REST; REQUIREMENTS; SPACEFLIGHT; METABOLISM; HUMANS; O-18 AB Energy requirements during space flight are poorly defined because they depend on metabolic-balance studies, food disappearance, and dietary records. Water turnover has been estimated by balance methods only. The purpose of this study was to determine energy requirements and water turnover for short-term space flights (8-14 d). Subjects were 13 male astronauts aged 36-51 y with normal body mass indexes (BMIs). Total energy expenditure (TEE) was determined during both a ground-based period and space flight and compared with the World Health Organization (WHO) calculations of energy requirements and dietary intake. TEE was not different for the ground-based and the space-flight periods (12.40 +/- 2.83 and 11.70 +/- 1.89 MJ/d, respectively), and the WHO calculation using the moderate activity correction was a good predictor of TEE during space flight. During the ground-based period, energy intake and TEE did not differ, but during space flight energy intake was significantly lower than TEE; body weight was also less at landing than before flight, Water turnover was lower during space flight than during the ground-based period (2.7 +/- 0.6 compared with 3.8 +/- 0.5 L/d), probably because of lower fluid intakes and perspiration loss during flight. This study confirmed that the WHO calculation can be used for male crew members' energy requirements during short space flights. C1 KRUG LIFE SCI INC,HOUSTON,TX. UNIV CHICAGO,DEPT MED,CHICAGO,IL 60637. NASA,LYNDON B JOHNSON SPACE CTR,SPACE & LIFE SCI DIRECTORATE,NUTR & METAB LAB,HOUSTON,TX 77058. NASA,LYNDON B JOHNSON SPACE CTR,SPACE & LIFE SCI DIRECTORATE,STABLE ISOTOPE LAB,HOUSTON,TX 77058. NR 39 TC 55 Z9 56 U1 1 U2 2 PU AMER SOC CLINICAL NUTRITION PI BETHESDA PA 9650 ROCKVILLE PIKE, SUBSCRIPTIONS, RM L-2310, BETHESDA, MD 20814-3998 SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD JAN PY 1997 VL 65 IS 1 BP 4 EP 12 PG 9 WC Nutrition & Dietetics SC Nutrition & Dietetics GA WA658 UT WOS:A1997WA65800001 PM 8988906 ER PT J AU Beck, LR Rodriguez, MH Dister, SW Rodriguez, AD Washino, RK Roberts, DR Spanner, MA AF Beck, LR Rodriguez, MH Dister, SW Rodriguez, AD Washino, RK Roberts, DR Spanner, MA TI Assessment of a remote sensing-based model for predicting malaria transmission risk in villages of Chiapas, Mexico SO AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE LA English DT Article ID ANOPHELES-ALBIMANUS; AMERICA; AREAS AB A blind test of two remote sensing-based models for predicting adult populations of Anopheles albimanus in villages, an indicator of malaria transmission risk, was conducted in southern Chiapas, Mexico. One model was developed using a discriminant analysis approach, while the other was based on regression analysis. The models were developed in 1992 for an area around Tapachula, Chiapas, using Landsat Thematic Mapper (TM) satellite data and geographic information system functions. Using two remotely sensed landscape elements, the discriminant model was able to successfully distinguish between villages with high and low An. albimanus abundance with an overall accuracy of 90%. To test the predictive capability of the models, multitemporal TM data were used to generate a landscape map of the Huixtla area, northwest of Tapachula, where the models were used to predict risk for 40 villages. The resulting predictions were not disclosed until the end of the test. Independently, An. albimanus abundance data were collected in the 40 randomly selected villages for which the predictions had been made. These data were subsequently used to assess the models' accuracies. The discriminant model accurately predicted 79% of the high-abundance villages and 50% of the low-abundance villages, for an overall accuracy of 70%. The regression model correctly identified seven of the 10 villages with the highest mosquito abundance. This test demonstrated that remote sensing-based models generated for one area can be used successfully in another, comparable area. C1 INST NACL SALUD PUBL,CTR INVEST ENFERMEDADES INFECCIOSAS,CUERNAVACA,MORELOS,MEXICO. UNIV CALIF DAVIS,DEPT ENTOMOL,DAVIS,CA 95616. UNIFORMED SERV UNIV HLTH SCI,BETHESDA,MD 20814. MINIST HLTH,CTR INVEST PALUDISMO,TAPACHULA 30700,CHIAPAS,MEXICO. RP Beck, LR (reprint author), NASA,AMES RES CTR,JOHNSON CONTROLS WORLD SERV INC,MAILSTOP 242-4,MOFFETT FIELD,CA 94035, USA. NR 11 TC 73 Z9 82 U1 0 U2 3 PU AMER SOC TROP MED & HYGIENE PI MCLEAN PA 8000 WESTPARK DRIVE SUITE 130, MCLEAN, VA 22101 SN 0002-9637 J9 AM J TROP MED HYG JI Am. J. Trop. Med. Hyg. PD JAN PY 1997 VL 56 IS 1 BP 99 EP 106 PG 8 WC Public, Environmental & Occupational Health; Tropical Medicine SC Public, Environmental & Occupational Health; Tropical Medicine GA WL889 UT WOS:A1997WL88900020 PM 9063370 ER PT S AU Bindschadler, R AF Bindschadler, R BE Whillans, IM TI Actively surging West Antarctic ice streams and their response characteristics SO ANNALS OF GLACIOLOGY, VOL 24, 1997 SE ANNALS OF GLACIOLOGY LA English DT Proceedings Paper CT International Symposium on Changing Glaciers CY JUN 24-27, 1996 CL FJAERLAND, NORWAY SP Int Glaciol Soc AB Ice Streams B, D and E,West Antarctica, all show a longitudinal pattern of ice thickness change that is consistent with ongoing surge behavior modeled for glaciers. The measured pattern is not consistent with model response of any other scenario such as accumulation-rate change or changes on the ice shelf. Inland migration of the ice-stream onset is a requirement of this behavior pattern. If such a surge is presently taking place, the remaining lifetime of the West Antarctic ice sheet is 1200-6000 years. A complete surge period lasting 50 000-120 000 years is hypothesized, with a relatively brief surge phase (lasting 16 000-21 000 years) required to completely remove the West Antarctic ice sheet from its maximum extent. Applying classic glacier response theory demonstrates that the diffusive component of response is much faster for ice streams than for glaciers, making the identification of either kinematic waves or localized responses on ice streams unlikely. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bindschadler, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 29 Z9 29 U1 1 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-19-9 J9 ANN GLACIOL PY 1997 VL 24 BP 409 EP 414 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BK12Z UT WOS:000071281900070 ER PT S AU Zwally, HJ Giovinetto, MB AF Zwally, HJ Giovinetto, MB BE Walsh, JE TI Areal distribution of the oxygen-isotope ratio in Greenland SO ANNALS OF GLACIOLOGY, VOL 25, 1997: PAPERS FROM THE INTERNATIONAL SYMPOSIUM ON REPRESENTATION OF THE CRYOSPHERE IN CLIMATE AND HYDROLOGICAL MODELS HELD AT VICTORIA, BRITISH COLUMBIA, CANADA, 12-15 AUGUST 1996 SE ANNALS OF GLACIOLOGY LA English DT Proceedings Paper CT International Symposium on Representation of the Cryosphere in Climate and Hydrological Models CY AUG 12-15, 1996 CL VICTORIA, CANADA SP Int Glaciol Soc, Atmospher Environm Serv, Canada, Inst Earth Sci, Canada, Univ Victoria, Ctr Earth & Ocean Res, Canadian Meteorol & Oceang Soc AB Mean values of the oxygen-isotope ratio relative to standard mean ocean water (delta(18)O, in 0/00) reported for 46 sites on the Greenland ice sheet are compiled together with data on mean annual surface temperature, latitude. delta(18)O elevation, and mean annual shortest distance to the open ocean denoted by the 10% sea-ice concentration boundary Stepwise regression analyses, with delta(18)O as the dependent variable, define two robust models. In the forward mode at the 99.9% confidence level, only temperature enters the model. In the backward mode at the 95% confidence level, only temperature, latitude and distance to the open ocean remain in the model. Inversions of the models on the basis of 160 gridpoint locations 100 km apart in the area delimited by the surface equilibrium line produce four contoured distributions of delta(18)O Two distributions are based on the bivariate model and two on the multivariate model. The second distribution for each model is obtained substituting mean annual surface-temperature values obtained from the Nimbus-7 Temperature Humidity Infrared Radiometer (THIR) database. All four distributions are considered valid, and differences between them are evaluated using contoured anomaly maps. It is suggested that the inversion of the multivariate model using THIR data provides the more reliable pattern for studies of atmospheric advection or for the derivation of ice-flow adjustments for delta(18)O series obtained from deep-core or ablation-zone sites. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zwally, HJ (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-20-2 J9 ANN GLACIOL PY 1997 VL 25 BP 208 EP 213 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Oceanography SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Oceanography GA BK58K UT WOS:000072623800037 ER PT S AU Kwok, R Comiso, JC AF Kwok, R Comiso, JC BE Walsh, JE TI The perennial ice cover of the Beaufort Sea from active- and passive-microwave observations SO ANNALS OF GLACIOLOGY, VOL 25, 1997: PAPERS FROM THE INTERNATIONAL SYMPOSIUM ON REPRESENTATION OF THE CRYOSPHERE IN CLIMATE AND HYDROLOGICAL MODELS HELD AT VICTORIA, BRITISH COLUMBIA, CANADA, 12-15 AUGUST 1996 SE ANNALS OF GLACIOLOGY LA English DT Proceedings Paper CT International Symposium on Representation of the Cryosphere in Climate and Hydrological Models CY AUG 12-15, 1996 CL VICTORIA, CANADA SP Int Glaciol Soc, Atmospher Environm Serv, Canada, Inst Earth Sci, Canada, Univ Victoria, Ctr Earth & Ocean Res, Canadian Meteorol & Oceang Soc AB The perennial ice concentration in the Beaufort Sea was examined using active-and passive-microwave observations. We compared the ice type and concentration estimates from SSM/I and ERS-I SAR data over a seasonal cycle from January 1992 to January 1993. It was found the multi-year (MY) ice-concentration estimates from the SAR data were very stable and were nearly equivalent to the ice concentration estimated at the end of the previous summer. We contrast this with the variability of the MY ice-concentration and ice-fraction estimates obtained using the NASA Team algorithm. The passive-and active-microwave algorithms provide total ice concentrations that are comparable during the winter, but the passive estimates are significantly lower during the summer. Passive-microwave estimates of multi-year-ice concentrations are consistently lower (up to 30%) than those from the SAR data. We discuss reasons for these discrepancies and the possible biases introduced by the active and passive algorithms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 4 U1 0 U2 0 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-20-2 J9 ANN GLACIOL PY 1997 VL 25 BP 376 EP 381 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Oceanography SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Oceanography GA BK58K UT WOS:000072623800065 ER PT J AU Lutz, RR Woodhouse, RM AF Lutz, RR Woodhouse, RM TI Requirements analysis using forward and backward search SO ANNALS OF SOFTWARE ENGINEERING LA English DT Article; Proceedings Paper CT 2nd International Conference on Requirements Engineering CY APR 15-18, 1996 CL COLORADO SPRINGS, CO SP IEEE, Comp Soc, Tech Council Software Engn ID CONTROL-SYSTEMS; SOFTWARE AB The requirements analysis of critical software components often involves a search for hazardous states and failure modes. This paper describes the integration of a forward search for consequences of reaching these forbidden modes' with a backward search for contributing causes. Results are reported from two projects in which the integrated search method was used to analyze the requirements of critical spacecraft software. The search process was found to be successful in identifying some ambiguous, inconsistent, and missing requirements. More importantly, it identified four significant, unresolved requirements issues involving complex system interfaces and unanticipated dependencies. The results suggest that recent efforts by researchers to integrate forward and backward search have merit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lutz, RR (reprint author), Iowa State Univ, Dept Comp Sci, Ames, IA 50011 USA. EM robyn.r.lutz@jpl.nasa.gov; robert.m.woodhouse@jpl.nasa.gov NR 31 TC 25 Z9 25 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1022-7091 J9 ANN SOFTW ENG JI Ann. Softw. Eng. PY 1997 VL 3 BP 459 EP 475 DI 10.1023/A:1018929719710 PG 17 WC Computer Science, Software Engineering SC Computer Science GA YP168 UT WOS:000071249400019 ER PT S AU Newman, JS AF Newman, JS GP IEEE TI ''IPPD+: New approaches for the new business environment'' SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 1997 PROCEEDINGS: THE INTERNATIONAL SYMPOSIUM ON PRODUCT QUALITY & INTEGRITY SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Proceedings Paper CT Annual Reliability and Maintainability Symposium on Meeting the Needs of the 21st Century CY JAN 13-16, 1997 CL PHILADELPHIA, PA SP IEEE DE IPPD; new business environment; advanced quality; performance-based contracting; risk management AB Integrated Product and Process Development (IPPD) cannot stand alone. The interconnectivity and relationships between the IPPD approach and the surrounding business management environment determine whether or not success is realized. Thus the notion of IPPD+. This paper builds a ''solution set'' of business practices centered on and incorporating IPPD. This set, IPPD+, is proposed as a viable means to achieve success in the new business environment. External forces demand that corporations and governments find new ways of doing business to remain successful. The Darwinian challenge must be met. We are evolving toward an integrated approach to program and project management. As we evolve, we must: recognize the importance of reforming the way people and business relationships are managed; seek reform in the way contractors are selected and in the way contracts are written; reduce government oversight and increase contractor self governance. Pursuit of a holistic, IPPD+ approach will allow the vision of ''Faster/Better/Cheaper'' to become a reality. RP Newman, JS (reprint author), NASA,OFF SAFETY & MISSION ASSURANCE,CODE Q,300 E ST SW,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-144X BN 0-7803-3783-2 J9 P A REL MAI PY 1997 BP 7 EP 12 DI 10.1109/RAMS.1997.570021 PG 6 WC Computer Science, Software Engineering SC Computer Science GA BH08B UT WOS:A1997BH08B00002 ER PT S AU Schneider, C Doherty, F Ridgeway, P Norley, G AF Schneider, C Doherty, F Ridgeway, P Norley, G GP IEEE TI PANEL: The GIQLP - Product integrity's link to acquisition reform SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 1997 PROCEEDINGS: THE INTERNATIONAL SYMPOSIUM ON PRODUCT QUALITY & INTEGRITY SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Proceedings Paper CT Annual Reliability and Maintainability Symposium on Meeting the Needs of the 21st Century CY JAN 13-16, 1997 CL PHILADELPHIA, PA SP IEEE DE acquisition reform; single process; process quality; advanced quality; IPPD; robust design RP Schneider, C (reprint author), NASA,CODE Q,300 E ST SW,WASHINGTON,DC 20546, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-144X BN 0-7803-3783-2 J9 P A REL MAI PY 1997 BP 26 EP 28 DI 10.1109/RAMS.1997.571659 PG 3 WC Computer Science, Software Engineering SC Computer Science GA BH08B UT WOS:A1997BH08B00005 ER PT S AU Bavuso, SJ AF Bavuso, SJ GP IEEE TI Aerospace applications of Weibull and Monte Carlo simulation with importance sampling SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 1997 PROCEEDINGS: THE INTERNATIONAL SYMPOSIUM ON PRODUCT QUALITY & INTEGRITY SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Proceedings Paper CT Annual Reliability and Maintainability Symposium on Meeting the Needs of the 21st Century CY JAN 13-16, 1997 CL PHILADELPHIA, PA SP IEEE DE Weibull; Monte Carlo; simulation; importance sampling; HARP (Hybrid Automated Reliability Prediction); Fault tree HiRel (HARP integrated Reliability tool system) AB Recent developments in reliability modeling and computer technology have made it practical to use the Weibull time to failure distribution to model the system reliability of complex fault-tolerant computer-based systems. These system models are becoming increasingly popular in space systems applications as a result of mounting data that support the decreasing Weibull failure distribution and the expectation of increased system reliability. This presentation introduces the new reliability modeling developments and demonstrates their application to a novel space system application. The application is a proposed guidance, navigation, and control (GN&C) system for use in a long duration manned spacecraft for a possible Mars mission. Comparisons to the constant failure rate model are presented and the ramifications of doing so are discussed. RP Bavuso, SJ (reprint author), NASA,LANGLEY RES CTR,MS 130,HAMPTON,VA 23681, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-144X BN 0-7803-3783-2 J9 P A REL MAI PY 1997 BP 208 EP 210 DI 10.1109/RAMS.1997.571708 PG 3 WC Computer Science, Software Engineering SC Computer Science GA BH08B UT WOS:A1997BH08B00034 ER PT S AU Boyd, MA Khalil, AA Herrin, SA AF Boyd, MA Khalil, AA Herrin, SA GP IEEE TI Real-time automated diagnosis for human-computer based monitoring and control systems SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 1997 PROCEEDINGS: THE INTERNATIONAL SYMPOSIUM ON PRODUCT QUALITY & INTEGRITY SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Proceedings Paper CT Annual Reliability and Maintainability Symposium on Meeting the Needs of the 21st Century CY JAN 13-16, 1997 CL PHILADELPHIA, PA SP IEEE DE automated diagnostics; matrix FMEA; troubleshooting; trend analysis; airborne telescope; human operated command and control system; rapid diagnosis and repair AB Many real-time monitoring and control systems are designed to be computer-based but to still retain significant roles for humans in operating and supervising the performance of the overall system. Examples of this type of monitoring and control system may be found in control rooms for wind tunnels, mission control rooms for spacecraft, and control rooms for power plants and manufacturing plants. These monitoring and control systems may also be found on board research and surveillance aircraft. The requirements of the human operator's supervisory role in these systems may tax the physiological limits of human mental concentration and physical endurance. These human limitations could negatively influence the safety and performance capabilities of the overall system. This paper describes a prototype System Health Management (SHM) system which was designed to automate some of the human monitoring and diagnosis tasks for the operations crew of the Kuiper Airborne Observatory (KAO), an airborne telescope system. The intent in developing such a system is to ease the burden on the human operators by automating the more monotonous tasks that are difficult for humans to perform well over an extended period of time, thereby freeing them to devote their concentration to the more skill-oriented tasks at which they tend to excel. A second intent is to assist the human operators in quickly diagnosing and repairing failures in flight. The combined effect of these benefits is expected to be better efficiency in the operation of the overall system (i.e. fewer human operators needed), and a reduction of lost science (data acquisition) due to equipment failures. C1 CAELUM RES CORP,MOFFETT FIELD,CA 94035. RP Boyd, MA (reprint author), NASA,AMES RES CTR,MAIL STOP 269-4,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0149-144X BN 0-7803-3783-2 J9 P A REL MAI PY 1997 BP 355 EP 360 DI 10.1109/RAMS.1997.571733 PG 6 WC Computer Science, Software Engineering SC Computer Science GA BH08B UT WOS:A1997BH08B00059 ER PT J AU Hollenbach, DJ Tielens, AGGM AF Hollenbach, DJ Tielens, AGGM TI Dense photodissociation regions (PDRs) SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Review DE interstellar medium; astrochemistry; infrared astronomy; nebulae; atomic processes ID DIFFUSE INTERSTELLAR CLOUDS; INTER-STELLAR CLOUDS; FLUORESCENT MOLECULAR-HYDROGEN; FAR-INFRARED SPECTROSCOPY; PHOTON-DOMINATED REGIONS; H-II REGIONS; SPATIAL-RESOLUTION OBSERVATIONS; REFLECTION NEBULA NGC-2023; POTENTIAL-ENERGY SURFACES; REGULATED STAR FORMATION AB All neutral atomic hydrogen gas and a large fraction of the molecular gas in the Milky Way Galaxy and external galaxies lie in PDRs, and PDRs are the origin of most of the nonstellar infrared (IR) and the millimeter CO emission from a galaxy. On the surfaces (A(v) < 1-3) of interstellar clouds, the absorption of far ultraviolet (FUV) photons (hv < 13.6 eV) by gas and dust grains leads to intense emission of [C II] 158 mu m, [O I] 63, 146 mu m, and H-2 rovibrational transitions, as well as IR dust continuum and polycyclic aromatic hydrocarbon (PAH) emission features. Deeper in PDRs, CO rotational and [C I] 370, 609 mu m Lines originate. The transition of H to H-2 and C+ to CO occurs within PDRs. Theoretical models compared with observations diagnose such physical parameters as the density and temperature structure, the elemental abundances, and the FUV radiation field in PDRs. Applications include clouds next to H II regions, reflection nebulae, planetary nebulae, red giant outflows, circumstellar gas around young stars, diffuse clouds, the warm neutral medium (WNM), and molecular clouds in the interstellar radiation field: in summary, much of the interstellar medium in galaxies. This review focuses on dense PDRs in the Milky Way Galaxy. Theoretical PDR models help explain the observed correlation of the CO J = 1-0 luminosity with the molecular mass and also suggest FUV-induced feedback mechanisms that may regulate star formation rates and the column density through giant molecular clouds. RP NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 285 TC 310 Z9 310 U1 1 U2 5 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4146 J9 ANNU REV ASTRON ASTR JI Annu. Rev. Astron. Astrophys. PY 1997 VL 35 BP 179 EP 215 DI 10.1146/annurev.astro.35.1.179 PG 37 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XX692 UT WOS:A1997XX69200008 ER PT J AU Brown, RH Cruikshank, DP AF Brown, RH Cruikshank, DP TI Determination of the composition and state of icy surfaces in the outer solar system SO ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES LA English DT Review DE icy satellites; solar-system volatiles; outer solar system; surface composition; isotopic abundances ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; AMORPHOUS SOLID WATER; CLATHRATE HYDRATE; OPTICAL-CONSTANTS; CARBON-DIOXIDE; NITROGEN ICE; TRITON; TEMPERATURE; PLUTO; FRACTIONATION AB Telescopic data combined with data gathered by spacecraft has brought worlds as distant as Pluto and the Kuiper belt objects under increasingly close scrutiny. Of particular interest here is the progress that has been made in our understanding of the properties of the satellites of the giant planets. As such, the purpose of this chapter is to review the present understanding of the nature of icy surfaces in the outer solar system, the ongoing processes that affect the composition, distribution, and physical state of volatiles on icy surfaces, and new techniques for probing the mysteries of the origin and evolution of icy bodies in the Solar System. C1 UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85721. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RP Brown, RH (reprint author), UNIV ARIZONA,LUNAR & PLANETARY LAB,TUCSON,AZ 85721, USA. NR 48 TC 29 Z9 29 U1 0 U2 0 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 0084-6597 J9 ANNU REV EARTH PL SC JI Annu. Rev. Earth Planet. Sci. PY 1997 VL 25 BP 243 EP 277 DI 10.1146/annurev.earth.25.1.243 PG 35 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA XB772 UT WOS:A1997XB77200008 ER PT J AU Rind, D Rosenzweig, C Stieglitz, M AF Rind, D Rosenzweig, C Stieglitz, M TI The role of moisture transport between ground and atmosphere in global change SO ANNUAL REVIEW OF ENERGY AND THE ENVIRONMENT LA English DT Review DE global warming; water availability; climate change; evapotranspiration; potential evapotranspiration ID SURFACE-TEMPERATURE; CLIMATE; EVAPORATION; VEGETATION; BALANCE; MODELS AB Projections of the effect of climate change on future water availability are examined by reviewing the formulations used to calculate moisture transport between the ground and the atmosphere. General circulation models and climate change impact models have substantially different formulations for evapotranspiration, so their projections of future water availability often disagree, even though they use the same temperature and precipitation forecasts. General circulation models forecast little change in tropical and subtropical water availability, while impact models show severe water and agricultural shortages. A comparison of observations and modeling techniques shows that the parameterizations in general circulation models likely lead to an underestimate of the impacts of global warming on soil moisture and vegetation. Such errors would crucially affect the temperature and precipitation forecasts used in impact models. Some impact model evaporation formulations are probably more appropriate than those in general circulation models, but important questions remain. More observations are needed, especially in the vicinity of forests, to determine appropriate parameterizations. C1 COLUMBIA UNIV,LAMONT DOHERTY EARTH OBSERV,NEW YORK,NY 10027. RP Rind, D (reprint author), NASA,GODDARD SPACE FLIGHT CTR,INST SPACE STUDIES,NEW YORK,NY 10025, USA. NR 49 TC 8 Z9 8 U1 0 U2 2 PU ANNUAL REVIEWS INC PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 SN 1056-3466 J9 ANNU REV ENERG ENV JI Annu. Rev. Energ. Environ. PY 1997 VL 22 BP 47 EP 74 DI 10.1146/annurev.energy.22.1.47 PG 28 WC Energy & Fuels; Engineering, Environmental SC Energy & Fuels; Engineering GA YK276 UT WOS:A1997YK27600004 ER PT J AU Mavriplis, DJ AF Mavriplis, DJ TI Unstructured grid techniques SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE computational; fluid; Navier-Stokes; aerodynamic; mesh; multigrid ID QUADRILATERAL MESH GENERATION; COMPUTATIONAL FLUID-DYNAMICS; FINITE-ELEMENT FORMULATION; NAVIER-STOKES EQUATIONS; EULER EQUATIONS; DELAUNAY TRIANGULATION; CORRECTED TRANSPORT; DIFFERENCE-SCHEMES; MULTIGRID APPROACH; ADAPTIVE MESHES AB An overview of the current state of the art in unstructured mesh techniques for computational fluid dynamics is given. The topics of mesh generation and adaptation, spatial discretization, and solution techniques for steady flows are covered. Remaining difficulties in these areas are highlighted, and directions for future work are outlined. RP NASA, LANGLEY RES CTR, INST COMP APPL SCI & ENGN, HAMPTON, VA 23681 USA. NR 125 TC 108 Z9 115 U1 0 U2 14 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 1997 VL 29 BP 473 EP 514 DI 10.1146/annurev.fluid.29.1.473 PG 42 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA WH488 UT WOS:A1997WH48800015 ER PT S AU Singh, JJ AF Singh, JJ BE Duggan, JL Morgan, IL TI Microstructural characterization of earth and space processed polymers with positrons SO APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY - PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL CONFERENCE, PTS 1 AND 2 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Conference on Application of Accelerators in Research and Industry CY NOV 06-09, 1996 CL UNIV N TEXAS, PHYS DEPT, DENTON, TX SP US DOE, Natl Sci Fdn, UNT, Amer Phys Soc, Div Nucl Phys HO UNIV N TEXAS, PHYS DEPT AB Positrons provide a versatile probe for monitoring microstructural features of molecular solids. In this paper, we report on positron lifetime measurements in two different types of polymers. The first group comprises polyacrylates processed on earth and in space. The second group includes fully-compatible and totally-incompatible Semi-Interpenetrating polymer networks of thermosetting and thermoplastic polyimides. On the basis of lifetime measurements, it is concluded that free volumes are a direct reflection of physical/electromagnetic properties of the host polymers. RP Singh, JJ (reprint author), NASA,LANGLEY RES CTR,MAIL STOP 235,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-652-2 J9 AIP CONF PROC PY 1997 IS 392 BP 473 EP 476 PG 4 WC Nuclear Science & Technology; Physics, Applied; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Nuclear Science & Technology; Physics GA BJ23A UT WOS:A1997BJ23A00116 ER PT B AU DeYoung, RJ Halama, GE Luck, WS Ellis, KS Sandford, SP Browell, EV Refaat, T AF DeYoung, RJ Halama, GE Luck, WS Ellis, KS Sandford, SP Browell, EV Refaat, T BE Sedlacek, AJ Fischer, KW TI Advanced detectors, optics, and waveform digitizers for aircraft DIAL water vapor measurements SO APPLICATION OF LIDAR TO CURRENT ATMOSPHERIC TOPICS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on the Application of Lidar to Current Atmospheric Topics II, at the SPIE Annual Meeting on Optical Engineering CY JUL 31-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE lidar receivers; avalanche photodiodes; waveform digitizers; lidar optics AB NASA Langley has an active water vapor differential absorption lidar (DIAL) program taking measurements from both C-130 and ER-2 aircraft. A research effort has started to increase the signal-to-noise ratio in the DIAL, receiver by 1) evaluating new very low noise avalanche photo diodes(APD), 2) designing an optics system that will focus the return light signal to the APD efficiently and 3) constructing a 10-MHz waveform digitizer board that will be small enough to be placed at the APD and telescope. With these advances we anticipate improving the signal-to-noise ratio by a factor often over the current receiver system. RP DeYoung, RJ (reprint author), NASA,LANGLEY RES CTR,MS401A,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2549-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3127 BP 103 EP 115 DI 10.1117/12.279067 PG 13 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BJ90X UT WOS:A1997BJ90X00008 ER PT B AU DeYoung, RJ Situ, W AF DeYoung, RJ Situ, W BE Sedlacek, AJ Fischer, KW TI Ti:sapphire laser system for aircraft measurements of atmospheric ozone SO APPLICATION OF LIDAR TO CURRENT ATMOSPHERIC TOPICS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on the Application of Lidar to Current Atmospheric Topics II, at the SPIE Annual Meeting on Optical Engineering CY JUL 31-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE DIAL; Ti:sapphire laser; flashlamp pumped; lidar AB A flashlamp pumped Ti:sapphire laser has been constructed which could be used to make atmospheric DIAL measurements of ozone from aircraft. A 9-mm diameter by 15-cm long rod is pumped by four flashlamps, two lamps fired in series at a time with 300 microsecond time separation between firings to produce the ''on'' and ''off'' line DIAL laser pulses. The laser cavity has two arms, one lasing at 867-nm and the other at 897-nm. The Q-switched output is doubled and tripled with a LBO and BBO crystal respectively to achieve DIAL pulses at 289-nm and 299-nm. Line narrowing is achieved with the use of three SF-10 prisms. Such a system could be used on an unpiloted atmospheric vehicle. RP DeYoung, RJ (reprint author), NASA,LANGLEY RES CTR,MS 401A,HAMPTON,VA 23681, USA. NR 0 TC 0 Z9 0 U1 2 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2549-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3127 BP 247 EP 254 DI 10.1117/12.283911 PG 8 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BJ90X UT WOS:A1997BJ90X00021 ER PT B AU Young, EW Gong, Q AF Young, EW Gong, Q BE Sedlacek, AJ Fischer, KW TI Interferometric performance analysis of a geostationary sounder SO APPLICATION OF LIDAR TO CURRENT ATMOSPHERIC TOPICS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on the Application of Lidar to Current Atmospheric Topics II, at the SPIE Annual Meeting on Optical Engineering CY JUL 31-AUG 01, 1997 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE Interferometer; Fourier Transform Spectrometer; GOES; Sounder AB Various efforts are underway to improve meteorological sounding measurements. One such effort is the development of the GOES High Resolution Interferometer Sounder (GHIS) instrument. This instrument has the potential to enhance these measurements by providing higher spectral resolution and simultaneous broadband coverage. This instrument consists of a Fourier Transform Spectrometer (FTS). The heart of this FTS is a Michelson Interferometer. The degree to which the sounding performance is enhanced depends crucially on the performance of this interferometer. A system performance analysis of this interferometer is presented. The analysis is based on the MIT Lincoln Labs design of the GHIS instrument In the analysis, the interferometric modulation (fringe contrast) as a function of key system parameters is calculated. These parameters include the following: finite field of view, wavefront shear, tilt of interferometer elements, and multiple reflections in the beamsplitter. The impact of modulation changes on the spectral performance is computed by taking an appropriate fourier transform. RP Young, EW (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 717,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2549-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 3127 BP 307 EP 322 DI 10.1117/12.279074 PG 16 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BJ90X UT WOS:A1997BJ90X00027 ER PT B AU Padgett, C Zhu, M Suddarth, S AF Padgett, C Zhu, M Suddarth, S BE Rogers, SK TI Detection and orientation classifier for the VIGILANTE image processing system SO APPLICATIONS AND SCIENCE OF ARTIFICIAL NEURAL NETWORKS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Conference on Applications and Science of Artificial Neural Networks III CY APR 21-24, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE automatic target recognition; neural processor; eigenvectors; machine vision; system architecture AB VIGILANTE is an automated recognition and tracking system that closely integrates a sensing platform with a very large processing capability (over 2 TeraOPS). The architecture currently consists of an optical bench with multiple sensors, a large parallel analog pre-processor, and a digital 512 processor, parallel machine. Preliminary results on target detection and orientation are presented for an algorithm that is suitable for the VIGILANTE architecture. The technique makes use of eigenvectors calculated from image blocks (size 32x32) drawn from video sequences containing rocket targets. The eigenvectors are used to reduce the dimensionality of frame-lets (size 32x32) from the larger sensor images. These frame-lets are projected on to the eigenvectors and, the resultant values are then used as an input pattern to a feed forward neural network classifier. A description and evaluation of this algorithm (including precision limitations) with respect to VIGILANTE is provided. Experiments using this technique have generated near 99target and non-target images and close to 97% identification of the rocket type. RP Padgett, C (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91125, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2492-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3077 BP 191 EP 201 DI 10.1117/12.271479 PG 11 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BH60Z UT WOS:A1997BH60Z00021 ER PT B AU Fang, WC Udomkesmalee, S Alkalai, L AF Fang, WC Udomkesmalee, S Alkalai, L BE Rogers, SK TI A compact VLSI neural computer integrated with active pixel sensor for real-time machine vision applications SO APPLICATIONS AND SCIENCE OF ARTIFICIAL NEURAL NETWORKS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Conference on Applications and Science of Artificial Neural Networks III CY APR 21-24, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE automatic target recognition; array processors; active pixel sensor; multichip module; neural networks; parallel processing; smart sensor; VLSI AB A compact VLSI neural computer integrated with an active pixel sensor has been under development to mimic what is inherent in biological vision systems. This electronic eye-brain computer is targeted for real-time machine vision applications which require both high-bandwidth communication and highperformance computing for data sensing, synergy of multiple types of sensory information, feature extraction, target detection, target recognition, and control functions. The neural computer is based on a composite structure which combines Annealing Cellular Neural Network (ACNN) and Hierarchical Self-Organization Neural Network(HSONN). The ACNN architecture is a programmable and scalable multidimensional array of annealing neurons which are locally connected with their local neurons. Meanwhile, the HSONN adopts a hierarchical structure with nonlinear basis functions. The ACNN+HSONN neural computer is effectively designed to perform programmable functions for machine vision processing in all levels with its embedded host processor. It provides a two order-of-magnitude increase in computation power over the state-of-the-art microcomputer and DSP microelectronics. A compact current-mode VLSI design feasibility of the ACNN+HSONN neural computer is demonstrated by a 3-D 16x8x9-cube neuralprocessor chip design in a 2-mu m CMOS technology. Integration of this neural computer as one slice of a 4''x4'' multichip module into the 3-dimensional MCM based avionics architecture for NASA's New Millennium Program is also described. RP Fang, WC (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2492-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3077 BP 266 EP 275 DI 10.1117/12.271487 PG 10 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BH60Z UT WOS:A1997BH60Z00028 ER PT B AU Kiang, RK AF Kiang, RK BE Rogers, SK TI Rectifying airborne scanner measurements using neural networks SO APPLICATIONS AND SCIENCE OF ARTIFICIAL NEURAL NETWORKS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Conference on Applications and Science of Artificial Neural Networks III CY APR 21-24, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE neural networks; geometric rectification; airborne scanner; remote sensing AB Popularized by the images from weather satellites and other Earth observing satellites, remote sensing from space has already become a household term. Airborne remote sensing, however, still holds its important place in the development of the remote sensing technology and in many applications. Prototype, proof-of-concept instruments are flown on aircraft before their improved versions are deployed on space shuttles or satellites. Airborne remote sensing is also more practical for regional applications. Since an aircraft flies in the Earth's atmosphere, factors contributing to geometric distortion are less systematic and more random. Substantial amount of effort is usually required to rectify the measurements. In this study, a scanner model is developed to generate simulated aircraft measurements. A backpropagation network and other variations are used to map the measurement space to the physical space. For measurements conducted over extensive area, techniques of anchoring the training data is developed such that geometric rectification can be performed in segments. Advantages of the neural network methods over the traditional method, and the need of constrained optimization are discussed. RP Kiang, RK (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 902,GREENBELT,MD 20771, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2492-7 J9 P SOC PHOTO-OPT INS PY 1997 VL 3077 BP 525 EP 534 DI 10.1117/12.271513 PG 10 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BH60Z UT WOS:A1997BH60Z00055 ER PT B AU Bar-Cohen, Y Siegel, R Grandia, W AF Bar-Cohen, Y Siegel, R Grandia, W GP AMER SOC NONDESTRUCT TESTING INC AMER SOC NONDESTRUCT TESTING INC TI Noninvasive medical diagnostics & treatment using ultrasonics SO ASNT FALL CONFERENCE AND QUALITY TESTING SHOW: PAPER SUMMARIES LA English DT Proceedings Paper CT ASNT Fall Conference and Quality Testing Show CY OCT 20-24, 1997 CL PITTSBURGH, PA SP Amer Soc Nondestruct Testing Inc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NONDESTRUCTIVE TESTING PI COLUMBUS PA 1711 ARLINGATE LANE, PO BOX 28518, COLUMBUS, OH 43228-0518 USA BN 1-57117-068-5 PY 1997 BP 229 EP 231 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA BM59N UT WOS:000079196900059 ER PT B AU Ellison, RM AF Ellison, RM GP AMER SOC QUAL CONTROL AMER SOC QUAL CONTROL TI Reaching toward space: The evolution of auditing - Kennedy Space Center (KSC) audit program SO ASQC'S 51ST ANNUAL QUALITY CONGRESS PROCEEDINGS LA English DT Proceedings Paper CT 51st Annual Quality Control Congress of the American-Society-for-Quality-Control CY MAY 05-07, 1997 CL ORLANDO, FL SP Amer Soc Qual Control DE compliance audit; continuous improvement; process audit AB The following four abstracts discuss how Kennedy Space Center's changing audit program allows NASA, United Space Alliance, McDonnell Douglas Space & Defense Systems, and EG&G to perform auditing as a team. Each organization discusses recent auditing improvements which help ensure the United States Space Program remains first class. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Ellison, RM (reprint author), NASA, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC QUALITY CONTROL PI MILWAUKEE PA 611 E WISCONSIN AVENUE, MILWAUKEE, WI 53202 USA PY 1997 BP 405 EP 407 PG 3 WC Engineering, Industrial; Management SC Engineering; Business & Economics GA BK34H UT WOS:000071845700065 ER PT B AU Pence, W AF Pence, W BE Hunt, G Payne, HE TI Overview of the Ftools software development philosophy SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB This talk will describe some of the features that have lead to the success of the ftools project and have enabled it to produce and manage a large package of software with low development costs. The ftools software package is a modular, platform-independent set of programs for analyzing FITS format data files in general, with a strong emphasis on data from high energy astrophysics missions. Ftools development began in 1991 and has produced the main set of data analysis software for the current ASCA and XTE space missions and for other archival sets of Xray and gamma-ray data. One of the original requirements of ftools was to support both the IRAF and non-IRAF user communities, therefore the ftools software can be built either as an IRAF package or as a set of stand-alone executables that can be run directly from the host operating system. Platform-independence has been achieved in part by adopting FITS as the run-time data analysis format. Other external projects are now developing their own ftools analysis tools that can be layered on top of the existing ftools packages. We encourage further such collaborations as a cost effective way to develop new software. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pence, W (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 30 EP 33 PG 4 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100006 ER PT B AU Harrington, J Barrett, PE AF Harrington, J Barrett, PE BE Hunt, G Payne, HE TI Interactive data analysis environments BoF session SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB We conducted a discussion of interactive environments in which scientists handle data. Traditional astronomical packages (AIPS, IDL, IRAF, MIDAS, etc.) lack many modern language and interactive features, whereas modern interactive/scripting/rapid prototyping environments (Perl, Tcl, etc.) lack convenient and efficient numerical capability and a way to access existing astronomical code. Our focus was thus on how best to merge the capabilities of modern environments with astronomical data processing. To follow developments in this evolving field, we have set up a Web page that compares the available environments. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harrington, J (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 69 EP 72 PG 4 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100016 ER PT B AU Brown, LE Angelini, L AF Brown, LE Angelini, L BE Hunt, G Payne, HE TI POW: A Tcl/Tk plotting and image display interface tool for GUIs SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB We present a new Tcl/Tk based GUI interface tool which features plotting of curve and image data and allows for user input via return of regions or specific cursor positions. The package is accessible from C, Tcl, or FORTRAN. POW operates on data arrays, passed to it as pointers. Each data array sent to POW is treated as either an Image object or a Vector object. Vectors are combined to form Curves. Curves and Images may then be combined to form a displayed Graph. Several Graphs can be displayed in a single Tk toplevel window. The Graphs can be rearranged, magnified, and zoomed to regions of interest by the user. Individual graph axes can be "linked" to implement a "multiple y-axis" (or x-axis) plot. The POW display can be written out in Postscript, for printing. C1 NASA, Goddard Space Flight Ctr, Hughes STX, Greenbelt, MD 20771 USA. RP Brown, LE (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX, Code 664, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 128 EP 131 PG 4 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100030 ER PT B AU Pence, W Xu, JJ Brown, L AF Pence, W Xu, JJ Brown, L BE Hunt, G Payne, HE TI FV: A new FITS file visualization tool SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Meeting Abstract CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pence, W (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 261 EP 261 PG 1 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100060 ER PT B AU Rots, AH Hilldrup, KC AF Rots, AH Hilldrup, KC BE Hunt, G Payne, HE TI The XTE Data Finder (XDF) SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB All RXTE telemetry will be archived in a hierarchical database consisting entirely of FITS Binary Tables. We describe an interactive tool, the XTE Data Finder (XDF). Though initially designed purely as a navigational tool, XDF has proven to be equally successful as a means to provide users full access to the complete RXTE mission database through the Internet. C1 Univ Space Res Assoc, XTE Guest Observer Facil, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rots, AH (reprint author), Univ Space Res Assoc, XTE Guest Observer Facil, Goddard Space Flight Ctr, Code 660-2, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 275 EP 277 PG 3 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100064 ER PT B AU Corcoran, MF Harris, DE Brunner, HE Englhauser, JK Voges, WH Boller, TH Watson, MG Pye, JP AF Corcoran, MF Harris, DE Brunner, HE Englhauser, JK Voges, WH Boller, TH Watson, MG Pye, JP BE Hunt, G Payne, HE TI The ROSAT Results Archive: Tools and methods SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB The ROSAT Results Archive (RRA) is a publicly accessible collection of source lists, images, spectra, lightcurves and counting rates derived from pointed-phase observations of the ROSAT X-ray satellite observatory. The RRA contains X-ray source data from both the ROSAT Position Sensitive Proportional Counter (PSPC) and the ROSAT High Resolution Imager (HRI) instruments, using only data processed with the current (REV2) version of the processing system to ensure data uniformity and accuracy. Each detected source is visually inspected and possible problems are flagged. In this paper we describe the methods used to screen the data products and the GUI-based tools used to screen and access the data. C1 NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. RP Corcoran, MF (reprint author), NASA, Goddard Space Flight Ctr, USRA, LHEA, Code 660-2, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 314 EP 317 PG 4 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100074 ER PT B AU Giles, AB AF Giles, AB BE Hunt, G Payne, HE TI Real time science displays for the Proportional Counter Array experiment on the Rossi X-ray Timing Explorer SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS VI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 6th Annual Conference on Astronomical Data Analysis Software and Systems CY SEP 22-26, 1996 CL OMNI CHARLOTTESVILLE HOTEL, CHARLOTTESVILLE, VA SP Natl Radio Astron Observ, Univ Virginia, Dept Astron & Comp Sci, Associated Univ Inc, European So Observ, Gemini 8m Telescopes Project, Infrared Proc & Anal Ctr, NASA, Natl Ctr Supercomp Appl, Natl Optical Astron Observ, Natl Res Council Canada, Natl Sci Fdn, Smithsonian Astrophys Observ, Space Telescope Sci Inst, GE Fanuc Automat, Sprint Communicat, Sun Microsyst Inc HO OMNI CHARLOTTESVILLE HOTEL AB The Rossi X-ray Timing Explorer (RXTE) spacecraft contains a large Proportional Counter Array (PCA) experiment which produces high count rates for many X-ray sources. Telemetry from RXTE is returned via the NASA Tracking and Data Relay Satellite System (TDRSS) which provides a stream of nearly continuous real time data packets. This allows opportunity for some serious real time interpretation and decision making by the experiment controller, duty scientist, and Guest Observer (GO), if present. The GOs also have the option of arranging for the remote display of programs at their home institution. This paper briefly describes the available Science Monitoring subsystem display options. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Giles, AB (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-45-7 J9 ASTR SOC P PY 1997 VL 125 BP 389 EP 392 PG 4 WC Astronomy & Astrophysics; Computer Science, Interdisciplinary Applications SC Astronomy & Astrophysics; Computer Science GA BK80E UT WOS:000073444100091 ER PT J AU Grillmair, CJ Faber, SM Lauer, TR Hester, JJ Lynds, CR ONeil, EJ Scowen, PA AF Grillmair, CJ Faber, SM Lauer, TR Hester, JJ Lynds, CR ONeil, EJ Scowen, PA TI The nuclear region of M51 imaged with the HST Planetary Camera SO ASTRONOMICAL JOURNAL LA English DT Article ID GALAXIES AB We present high-resolution, broad- and narrow-band, pre-refurbishment images of the central region of M51 taken with the Planetary Camera of the Hubble Space Telescope, The V-band images show a rather chaotic distribution of dust lanes, though some are oriented radially, roughly aligned with the major axis of the bar, and may be transporting gas to the AGN in the nucleus, The dust lane obscuring the nucleus of the galaxy, which was previously thought to be an edge-on accretion disk feeding the AGN, is not centered on the nucleus, It is unlikely that this is a stable configuration, suggesting that the material has only recently entered the nuclear region, The nucleus is contained within a cluster of stars having a total luminosity of order 5 x 10(7) L.. Fitting a King model to the least obscured portions of the cluster yields a maximum core radius of 14 pc. The morphology apparent in the forbidden-line images of the extra-nuclear cloud is consistent with a narrow jet striking and scattering off the boundary of a relatively dense cocoon of gas in the disk of the galaxy. The emission-line regions are concentrated along the inner borders of dust filaments, supporting the view that the nuclear jet is ramming into and stirring up the ISM of the disk. (C) 1997 American Astronomical Society. C1 UNIV CALIF SANTA CRUZ,UNIV CALIF OBSERV,LICK OBSERV,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064. KITT PEAK NATL OBSERV,NATL OPT ASTRON OBSERV,TUCSON,AZ 85726. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. RP Grillmair, CJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 23 TC 19 Z9 20 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 1997 VL 113 IS 1 BP 225 EP & DI 10.1086/118246 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WC671 UT WOS:A1997WC67100016 ER PT B AU Scargle, JD AF Scargle, JD BE Maoz, D Sternberg, A Leibowitz, EM TI Astronomical time series analysis - New methods for studying periodic and aperiodic systems SO ASTRONOMICAL TIME SERIES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Florence-and-George-Wise-Observatory 25th Anniversary Symposium on Astronomical Time Series CY DEC 30, 1996-JAN 01, 1997 CL TEL AVIV UNIV, TEL AVIV, ISRAEL SP Florence & George Wise Observ, Tel Aviv Univ HO TEL AVIV UNIV AB Mathematical research has yielded new time series methods, such as multi-taper spectral analysis, and wavelets and their extensions. The corresponding algorithms are rapidly being developed for unevenly sampled time series data, characteristic of astronomy and other sciences. Combinations of several new and old techniques yield powerful tools for detecting and characterizing periodic, quasiperiodic, and aperiodic signals. I describe several such combined methods and apply them to bizarrely spaced radial velocity data from one of the newly-discovered extrasolar planetary systems. RP Scargle, JD (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,PLANETARY SYST BRANCH,MS 245-3,MOFFETT FIELD,CA 94035, USA. NR 0 TC 7 Z9 8 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4706-4 J9 ASTROPHYS SPACE SC L PY 1997 VL 218 BP 1 EP 12 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ58B UT WOS:A1997BJ58B00001 ER PT B AU Madejski, G Takahashi, T Kubo, H Sikora, M AF Madejski, G Takahashi, T Kubo, H Sikora, M BE Maoz, D Sternberg, A Leibowitz, EM TI Variable high energy emission of blazars SO ASTRONOMICAL TIME SERIES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Florence-and-George-Wise-Observatory 25th Anniversary Symposium on Astronomical Time Series CY DEC 30, 1996-JAN 01, 1997 CL TEL AVIV UNIV, TEL AVIV, ISRAEL SP Florence & George Wise Observ, Tel Aviv Univ HO TEL AVIV UNIV RP Madejski, G (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4706-4 J9 ASTROPHYS SPACE SC L PY 1997 VL 218 BP 259 EP 264 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ58B UT WOS:A1997BJ58B00038 ER PT J AU Herrmann, R Magun, A Kaufmann, P Correia, E Costa, JER Machado, ME Fishman, GJ AF Herrmann, R Magun, A Kaufmann, P Correia, E Costa, JER Machado, ME Fishman, GJ TI Evidence for highly inhomogeneous mm-wave sources during the impulsive flare of May 9, 1991 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun: flares; Sun: radio radiation; Sun: X-rays ID HARD X-RAY; SOLAR-FLARES; EMISSION; RESOLUTION; MILLIMETER; MICROWAVE; BURSTS; POLARIZATION AB In this paper multiwavelength observations of an impulsive flare of May 9, 1991 are presented. This event was observed with the 48 GHz multibeam focal array used at the Itapetinga radio telescope, the microwave patrol telescopes at Bern and the BATSE high time resolution hard X-ray spectrometer on board CGRO. While spatially unresolved low sensitivity observations show two major impulsive peaks, the mm-wave observations with the ability of spatially high resolved tracking of the emission centroids suggest a primarily bipolar source configuration. For the first time two mm-wave sources with a spacing below the HPBW could be separated with the multibeam technique. The general features of the observations are explained as emission of partially trapped electrons. Furthermore we present evidence for highly inhomogenous substructures within one of the two mm-wave sources for which the positional scatter of the emission center, within 2 s, is less than 2''. C1 UNIV BERN, INST APPL PHYS, CH-3012 BERN, SWITZERLAND. UNIV ALABAMA, DEPT PHYS, HUNTSVILLE, AL 35899 USA. CONAE, BUENOS AIRES, DF, ARGENTINA. UNICAMP, CRAAE, NUCATE, CAMPINAS, SP, BRAZIL. INPE, CRAAE, SAO PAULO, BRAZIL. NASA, MSFC, SPACE SCI LAB, HUNTSVILLE, AL USA. RI Costa, Joaquim/G-3840-2012; Correia, Emilia/F-6802-2012; OI Costa, Joaquim/0000-0002-0703-4735 NR 27 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 JAN PY 1997 VL 317 IS 1 BP 232 EP 243 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WP872 UT WOS:A1997WP87200041 ER PT J AU vanParadijs, J vandenHeuvel, EPJ Kouveliotou, C Fishman, GJ Finger, MH Lewin, WHG AF vanParadijs, J vandenHeuvel, EPJ Kouveliotou, C Fishman, GJ Finger, MH Lewin, WHG TI Evidence for neutron star formation from accretion induced collapse of a white dwarf SO ASTRONOMY & ASTROPHYSICS LA English DT Letter DE neutron star; X-ray binaries; stars: GRO J1744-28 ID MILLISECOND PULSARS; ORBITAL PERIOD; CENTAURUS X-4; FIELD DECAY; BINARY; EVOLUTION; MODELS; SYSTEM; ORIGIN AB The orbital parameters of the recently discovered transient burster/pulsar GRO J1744-28 indicate that this system is a low-mass X-ray binary in an advanced stage of its mass transfer, with several tenths of a solar mass already transferred from the donor to the compact star, All neutron stars known to have accreted such an amount have very weak magnetic fields, and this has led to the idea that the magnetic fields of neutron stars decay as a result of accretion. The observation of a strongly magnetized neutron star in GRO J1744-28 then suggests that this neutron star was formed recently as a result of the collapse of a white dwarf during an earlier stage of the current phase of mass transfer. It is shown that this model can consistently explain the observed characteristics of GRO J1744-28, Attractive progenitors for such an evolution are the luminous supersoft X-ray sources detected with ROSAT. C1 CTR HIGH ENERGY ASTROPHYS, NL-1098 SJ AMSTERDAM, NETHERLANDS. UNIV ALABAMA, DEPT PHYS, HUNTSVILLE, AL 35899 USA. NASA, MARSHALL SPACE FLIGHT CTR, HUNTSVILLE, AL 35812 USA. MIT, CTR SPACE RES, CAMBRIDGE, MA 02139 USA. RP vanParadijs, J (reprint author), UNIV AMSTERDAM, ASTRON INST ANTON PANNEKOEK, KRUISLAAN 403, NL-1098 SJ AMSTERDAM, NETHERLANDS. NR 43 TC 18 Z9 18 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JAN PY 1997 VL 317 IS 1 BP L9 EP L12 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WP872 UT WOS:A1997WP87200004 ER PT S AU Wooden, DH AF Wooden, DH BE Bernatowicz, TJ Zinner, E TI Observational evidence for mixing and dust condensation in core-collapse supernovae SO ASTROPHYSICAL IMPLICATIONS OF THE LABORATORY STUDY OF PRESOLAR MATERIALS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Astrophysical Implications of the Laboratory Study of Presolar Materials CY OCT 31-NOV 02, 1996 CL WASHINGTON UNIV, STEINBERG GALLERY, ST LOUIS, MO SP Washington Univ, Dept Phys, Washington Univ, McDonnell Ctr Space Sci, NASA HO WASHINGTON UNIV, STEINBERG GALLERY AB Recent findings of isotopic anomalies of Ca-44 (the decay product of Ti-44) and the enhanced ratio of Si-28/Si-30 in SiC grains X, TiC subgrains, and graphite dust grains within primitive meteorites provides strong evidence that these presolar grains came from core-collapse supernovae. The chemical composition of the presolar grains requires macroscopic mixing of newly nucleosynthesized elements from explosive silicon burning at the innermost zone of the ejecta to higher velocities where C exists and where C/O > 1 in either the outer edge of the oxygen zone or in the He-C zone. To date, the only core-collapse supernova observed to form dust is the brightest supernova of the past four centuries, SN1987A in the Large Magellanic Cloud. Observations of SN1987A confirm large scale macroscopic mixing occurs in the explosions of massive stars. Rayleigh-Taylor instabilities macroscopically mix most of the ejecta into regions which are still chemically homogeneous and which cool with different time scales. Only small clumps in the ejecta are microscopically mixed. Observations show that dust condensed in the ejecta of SN1987A after similar to 500 days in the Fe-rich gas. Neither silicates nor SLC grains were seen in the dust emission spectrum of SN1987A. SN1987A, the Rosetta Stone of core-collapse supernovae, shows that while the mixing required to explain presolar grains occurs, the rapid cooling of the Fe zone and the sustained high temperatures of the O-Si, O-C, and He-C zones favor the formation of iron-rich rather than oxygen-or carbon-rich grains. RP Wooden, DH (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-664-6 J9 AIP CONF PROC PY 1997 IS 402 BP 317 EP 376 DI 10.1063/1.53315 PG 60 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ93J UT WOS:A1997BJ93J00013 ER PT S AU Tielens, AGGM AF Tielens, AGGM BE Bernatowicz, TJ Zinner, E TI Deuterium and interstellar chemical processes SO ASTROPHYSICAL IMPLICATIONS OF THE LABORATORY STUDY OF PRESOLAR MATERIALS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Astrophysical Implications of the Laboratory Study of Presolar Materials CY OCT 31-NOV 02, 1996 CL WASHINGTON UNIV, STEINBERG GALLERY, ST LOUIS, MO SP Washington Univ, Dept Phys, Washington Univ, McDonnell Ctr Space Sci, NASA HO WASHINGTON UNIV, STEINBERG GALLERY AB The high deuterium fractionation observed in many solar system bodies is generally taken as an indication of incorporation of interstellar material which never fully equilibrated with the solar nebula. In this paper, I review chemical processes that affect the deuteration of interstellar molecules. The emphasis is on identifying the major interstellar D-reservoirs available to the solar system in formation. Ion-molecule reactions driven by cosmic ray ionization are very efficient in deuterating interstellar molecules, However, the absolute levels of deuterated molecules produced this way are rather small and probably not very important to the solar nebula. An exception should be made for PAHs which may well lock up similar or equal to 1% of the D in dense cloud cores. The main effect of ion-molecule chemistry is to shift the atomic to molecular balance of deuterium (D/HD) in the direction of atomic D. As a result, the atomic D/H ratio in the gas phase is similar or equal to 1. Upon accretion on a grain surface, atomic D will deuterate grain mantle molecules such as H2O, CH3OH, H2CO, NH3, and CH4. This is likely the main route by which D was delivered to the outer, colder, solar system bodies. The chemistry of dense (similar or equal to 10(6) - 10(8) cm(-3)), warm (100-200 K) Hot Cores in star forming regions is reviewed with the emphasis on deuterated molecules. The central role of methanol, outgassed from icy grain mantles, in driving molecular complexity in the gas phase is recognized. It is likely, that the material which ended up in the solar nebula, went through a similar Hot Core phase. Finally, interstellar chemistry may also have left its traces in the C, N, and O isotopes of organic material available to the Solar System. RP Tielens, AGGM (reprint author), NASA,AMES RES CTR,DIV SPACE SCI,MS 245-S,MOFFETT FIELD,CA 94035, USA. NR 0 TC 15 Z9 15 U1 0 U2 0 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-664-6 J9 AIP CONF PROC PY 1997 IS 402 BP 523 EP 544 DI 10.1063/1.53335 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ93J UT WOS:A1997BJ93J00020 ER PT S AU Cassen, P Chick, KM AF Cassen, P Chick, KM BE Bernatowicz, TJ Zinner, E TI The survival of presolar grains during the formation of the solar system SO ASTROPHYSICAL IMPLICATIONS OF THE LABORATORY STUDY OF PRESOLAR MATERIALS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Astrophysical Implications of the Laboratory Study of Presolar Materials CY OCT 31-NOV 02, 1996 CL WASHINGTON UNIV, STEINBERG GALLERY, ST LOUIS, MO SP Washington Univ, Dept Phys, Washington Univ, McDonnell Ctr Space Sci, NASA HO WASHINGTON UNIV, STEINBERG GALLERY AB The presolar grains found in meteorites survived potentially destructive processes in the protosolar environment: the radiation field of the collapsing protosolar envelope; the protoplanetary disk formed by the collapse, known as the solar nebula; and the accretion shock through which material passed from the envelope to the disk. Theoretical models of these regimes, combined with experimentally determined destruction criteria, can be used, in principle, to put constraints on the physical conditions that prevailed prior to and during the formation of meteorite parent bodies. Preliminary studies, in which interstellar species are assumed to be destroyed at well-defined, critical temperatures, indicate that refractory species (e.g., silicates) survived envelope and shock to enter the nebula at or within about 1 AU of the Sun; volatile species such as water ice and simple organics retained interstellar characteristics only beyond several AU, the destruction distances being dependent on the protosolar accretion luminosity and, to a lesser extent, the precise density configuration of the protosolar envelope. Upon entering the nebula it is likely that even refractory grains were destroyed out to some distance in the terrestrial planet region, but subsequent nebular cooling and radial advection resulted in the survivors' incorporation into the meteorite parent bodies. Presolar volatiles would have been incorporated in comets formed at distances at and beyond the orbits of Uranus and Neptune. These preliminary conclusions should be tested by better theoretical models of the protosolar environment, a search for survival patterns among meteorite classes, and the application of rigorously defined destruction criteria which take into account the nonequilibrium character of surviving species. RP Cassen, P (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 10 Z9 10 U1 0 U2 1 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-664-6 J9 AIP CONF PROC PY 1997 IS 402 BP 697 EP 719 DI 10.1063/1.53324 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ93J UT WOS:A1997BJ93J00027 ER PT J AU Dopita, MA Vassiliadis, E Wood, PR Meatheringham, SJ Harrington, JP Bohlin, RC Ford, HC Stecher, TP Maran, SP AF Dopita, MA Vassiliadis, E Wood, PR Meatheringham, SJ Harrington, JP Bohlin, RC Ford, HC Stecher, TP Maran, SP TI Hubble Space Telescope observations of planetary nebulae in the Magellanic Clouds .5. Mass dependence of dredge-up and the chemical history of the large Magellanic Cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies, abundances; galaxies, Magellanic Clouds; planetary nebulae, general; stars, evolution ID ASYMPTOTIC GIANT BRANCH; LOW-EXCITATION PLANETARY; ANGULAR DIAMETERS; HEAVY-ELEMENTS; STAR-FORMATION; RED GIANTS; FAINT STAR; S-PROCESS; ABUNDANCES; EVOLUTION AB A photoionization analysis of Hubble Space Telescope UV and ground-based optical spectrophotometry is given for eight more planetary nebulae (PNs) in the Large Magellanic Cloud (LMC). This allows the central stars to be placed accurately on the H-R diagram and permits the determination of the He, C, N, O, Ne, S, and Ar abundances. In some cases, the gas-phase abundances of Mg and Si may also be determined. We have combined these results with the analysis of two other objects published by us in the first two papers of this series. The observed abundance patterns are qualitatively consistent with the (mass-dependent) operation of the various chemical dredge-up processes as predicted by theory, Dredge-up of C during the thermal pulsing stage appears to be most important, and ''hot bottom burning'' transforms much of this C to N in the more massive stars. There is no sign of drudge-up of Ne-22. We show that the spread in the alpha-process element abundances can be understood as being due to differences in core mass of the planetary nebula nucleus, which is related directly to initial mass of the precursor star. This is, therefore, a tracer of the age-metallicity relationship for stars in general, and we derive, for the first time, the chemical history of the LMC based on PNs. We find that the base metallicity of the LMC almost doubled similar to 2 Gyr ago. This is consistent with studies of field stars and of clusters that show that there was a major burst of star formation at the time. C1 SPACE TELESCOPE SCI INST,BALTIMORE,MD 21218. UNIV MARYLAND,DEPT ASTRON,COLLEGE PK,MD 20742. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Dopita, MA (reprint author), AUSTRALIAN NATL UNIV,MT STROMLO & SIDING SPRING OBSERV,INST ADV STUDIES,PRIVATE BAG,WESTON,ACT 2611,AUSTRALIA. RI Dopita, Michael/P-5413-2014 OI Dopita, Michael/0000-0003-0922-4986 NR 66 TC 98 Z9 99 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP 188 EP 204 DI 10.1086/303444 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA682 UT WOS:A1997WA68200015 ER PT J AU Chakrabarty, D Bildsten, L Grunsfeld, JM Koh, DT Prince, TA Vaughan, BA AF Chakrabarty, D Bildsten, L Grunsfeld, JM Koh, DT Prince, TA Vaughan, BA TI Torque reversal and spin-down of the accretion-powered pulsar 4U 1626-67 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries, close; pulsars, individual (4U 1626-67); stars, neutron; X-rays, stars ID X-RAY SOURCES; MAGNETIC NEUTRON STARS; MILLISECOND PULSATIONS; BINARY-SYSTEMS; PERIOD CHANGES; DISCOVERY; 4U-1626-67; EVOLUTION; SEARCHES; NOISE AB Over 5 yr of hard X-ray (20-60 keV) monitoring of the 7.66 s accretion-powered pulsar 4U 1626-67 with the Compton Gamma Ray Observatory/BATSE large-area detectors has revealed that the neutron star is now steadily spinning down, in marked contrast to the steady spin-up observed during 1977-1989. This is the second accreting pulsar (the other is GX 1 + 4) that has shown extended, steady intervals of both spin-up and spin-down. Remarkably, the magnitudes of the spin-up and spin-down torques differ by only 15%, with the neutron star spin changing on a timescale \nu over dot/nu double over dot\ approximate to 5000 yr in both states. The current spin-down rate is itself decreasing on a timescale \nu over dot/nu double over dot\ approximate to 26 yr. The long-term timing history shows small-amplitude variations on a 4000 day timescale, which are probably due to variations in the mass transfer rate. The pulsed 20-60 keV emission from 4U 1626-67 is well-fitted by a power-law spectrum with photon index gamma = 4.9 and a typical pulsed intensity of 1.5 x 10(-10) ergs cm(-2) s(-1). The low count rates with BATSE prohibited us from constraining the reported 42 minute binary orbit, but we can rule out long-period orbits in the range 2 days less than or similar to P-erb less than or similar to 900 days. We compare the long-term torque behavior of 4U 1626-67 to other disk-fed accreting pulsars and discuss the implications of our results for the various theories of magnetic accretion torques. The abrupt change in the sign of the torque is difficult to reconcile with the extremely smooth spin-down now observed. The strength of the torque noise in 4U 1626-67, similar to 10(-22) Hz(2) s(-2) Hz(-1), is the smallest ever measured for an accreting X-ray pulsar, and it is comparable to the timing noise seen in young radio pulsars. We close by pointing out that the core temperature and external torque (the two parameters potentially relevant to internal sources of timing noise) of an accreting neutron star are also comparable to those of young radio pulsars. C1 NASA, GEORGE C MARSHALL SPACE FLIGHT CTR, SPACE SCI LAB ES84, HUNTSVILLE, AL 35812 USA. RP Chakrabarty, D (reprint author), CALTECH, SPACE RADIAT LAB 22047, PASADENA, CA 91125 USA. NR 73 TC 75 Z9 75 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP 414 EP 425 DI 10.1086/303445 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA682 UT WOS:A1997WA68200032 ER PT J AU Giles, AB AF Giles, AB TI An efficient algorithm for the detection of infrequent rapid bursts in time series data SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods, data analysis; methods, statistical stars, individual (Cygnus X-1); stars, variables, other; X-rays, stars ID RAY TIMING EXPLORER; MILLISECOND PULSATIONS; CYGNUS X-1; SEARCHES; BINARIES AB Searching through data for infrequent rapid bursts is a common requirement in many areas of scientific research. In this paper, we present a powerful and flexible analysis method that, in a single pass through the data, searches for statistically significant bursts on a set of specified short timescales. The input data are binned, if necessary, and then quantified in terms of probabilities rather than rates or ratios. Using a measure-like probability makes the method relatively count rate independent. The method has been made computationally efficient by the use of lookup tables and cyclic buffers, and it is therefore particularly well suited to real-time applications. The technique has been developed specifically for use in an X-ray astronomy application to search for millisecond bursts from black hole candidates such as Cyg X-1. We briefly review the few observations of these types of features reported in the literature, as well as the variety of ways in which their statistical reliability was challenged. The developed technique, termed the burst expectation search (BES) method, is illustrated using some data simulations and archived data obtained during ground testing of the proportional counter array (PCA) experiment detectors on the Rossi X-ray Timing Explorer (RXTE). A potential application for a real-time BES method on board RXTE is also examined. RP Giles, AB (reprint author), NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771, USA. NR 24 TC 2 Z9 2 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP 464 EP 473 DI 10.1086/303439 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA682 UT WOS:A1997WA68200036 ER PT J AU Moiseev, A Yoshimura, K Ueda, I Anraku, K Golden, R Imori, M Inaba, S Kimbell, B Kimura, N Makida, Y Matsumoto, H Matsunaga, H Mitchell, J Motoki, M Nishimura, J Nozaki, M Orito, S Ormes, J Saeki, T Seo, ES Stochaj, S Streitmatter, R Suzuki, J Tanaka, K Yajima, N Yamagami, T Yamamoto, A Yoshida, T AF Moiseev, A Yoshimura, K Ueda, I Anraku, K Golden, R Imori, M Inaba, S Kimbell, B Kimura, N Makida, Y Matsumoto, H Matsunaga, H Mitchell, J Motoki, M Nishimura, J Nozaki, M Orito, S Ormes, J Saeki, T Seo, ES Stochaj, S Streitmatter, R Suzuki, J Tanaka, K Yajima, N Yamagami, T Yamamoto, A Yoshida, T TI Cosmic-ray antiproton flux in the energy range form 200 to 600 MeV SO ASTROPHYSICAL JOURNAL LA English DT Article DE balloons; cosmic rays; elementary particles ID PROTON RATIO; ANTI-PROTONS; RADIATION; ANNIHILATION; HELIUM; NUCLEI AB We have studied the low-energy antiprotons in the cosmic rays by utilizing data obtained by the Balloon-borne Experiment with a Superconducting magnetic rigidity Spectrometer (BESS) flown in 1993 July from Lynn Lake, Manitoba, Canada. A detailed description of the event selection criteria and back-ground corrections is given. Seven antiprotons are found that give an antiproton flux of 6.4(-3.5)(+5.5) x 10(-3)(m(2) sr s GeV)(-1) and an antiproton/proton ratio of 5.2(-2.8)(+4.4) x 10(-6) in the 200-600 MeV energy range. These results are consistent with a secondary origin of low-energy cosmic-ray antiprotons within our uncertainties, but they still require the precise measurement of the spectrum shape below 500 MeV to clarify exactly the model of particle propagation and possible contributions from exotic sources. C1 UNIV TOKYO,BUNKYO KU,TOKYO 113,JAPAN. NATL LAB HIGH ENERGY PHYS,KEK,TSUKUBA,IBARAKI 305,JAPAN. NEW MEXICO STATE UNIV,LAS CRUCES,NM 88003. KOBE UNIV,KOBE,HYOGO,JAPAN. INST SPACE & ASTRONAUT SCI,SAGAMIHARA,KANAGAWA 229,JAPAN. UNIV MARYLAND,COLLEGE PK,MD 20742. RP Moiseev, A (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI MOTOKI, Masakazu/B-4212-2009; OI Seo, Eun-Suk/0000-0001-8682-805X NR 42 TC 67 Z9 67 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP 479 EP 489 DI 10.1086/303463 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA682 UT WOS:A1997WA68200038 ER PT J AU Gorkavyi, NN Ozernoy, LM Mather, JC AF Gorkavyi, NN Ozernoy, LM Mather, JC TI A new approach to dynamical evolution of interplanetary dust SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared, solar system; interplanetary medium ID ASTEROIDAL DUST; PARTICLES; RING AB We introduce the continuity equation written in the coordinate space of the orbital elements (e.g., semimajor axis a versus eccentricity e, etc.). This equation can serve as an effective tool to analyze the transport of interplanetary dust particles as well as their dynamical evolution, and offers a very useful complement to the approach using purely numerical integration of orbits. Using the continuity equation and suitable analytical and numerical approximations, statistically useful results can be achieved very quickly, and new integrals of the motion can be sought to simplify the description of large-scale phenomena. This paper describes the method, illustrates it with a simple example of multiple gravitational scatterings of particles on planets in circular orbits in two dimensions, and outlines the program for further development with more accurate approximations. We describe the particle dynamical evolution due to gravitational scattering by means of the ''scattering matrix'' W(a e, a', e') in the continuity equation. This matrix determines both the probability of transition and the value of the particle's shift from the point a, e to the point a' e'. For purposes of illustration, two cases of the zodiacal particle diffusion due to gravitational scattering are computed, which are characterized by the initial conditions (1) (asteroid case), a(0) = 2.5 AU, e(0) = 0.4 (resonance 1:3 with Jupiter), and (2) (comet case), a(0) = 2.22 AU, e(0) = 0.846 (comet Encke). We discuss the approximations of the example and how they might be improved in future work. These include treatments of the Poynting-Robertson drag, interparticle collisions, secular perturbations, three-dimensional orbits, and resonance capture by the planets. For instance, analytical expressions are available for the rates of gradual change of orbital elements due to the Poynting-Robertson and solar wind drags, which can be incorporated easily in the ''div'' terms of the continuity equation. C1 GEORGE MASON UNIV,COMPUTAT SCI INST,DEPT PHYS & ASTRON,FAIRFAX,VA 22030. NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. RP Gorkavyi, NN (reprint author), CRIMEAN ASTROPHYS OBSERV,SIMEIZ DEPT,UA-334242 SIMEIZ,UKRAINE. NR 11 TC 17 Z9 17 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP 496 EP 502 DI 10.1086/303440 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA682 UT WOS:A1997WA68200040 ER PT J AU Cui, W Heindl, WA Rothschild, RE Zhang, SN Jahoda, K Focke, W AF Cui, W Heindl, WA Rothschild, RE Zhang, SN Jahoda, K Focke, W TI Rossi X-Ray Timing Explorer observations of Cygnus X-1 in its high state SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, general; stars, individual (Cygnus X-1); X-rays, stars ID VARIABILITY AB We present the results from the Rossi X-Ray. Timing Explorer observations of Cygnus X-l in its high stare. In the energy range of 2-200 keV, the observed X-ray spectrum can be described by a model consisting of a soft blackbody component and a broken power law with a high-energy cutoff. The low-energy spectrum (below similar to 11 keV) varies significantly from observation to observation while the high-energy portion changes little. The X-ray flux varies on all timescales down to milliseconds. The power density spectrum (PDS) can be characterized by excess red noise (''1/f'') at low frequencies and a white-noise component that extends to 1-3 Hz before being cut off. At higher frequencies, the PDS becomes power-law again, with a slope of roughly -2 (i.e., ''1/f(2)''). Broad peaks in the range of 3-9 Hz are present and might be due to quasi-periodic oscillations. The PDS shows interesting spectral dependence: the 1/f component becomes more prominent when the low-energy spectrum becomes softer. The difference in the observed spectral and timing properties between the low and high states is qualitatively consistent with a simple ''fluctuating corona'' model. C1 UNIV CALIF SAN DIEGO,CTR ASTROPHYS & SPACE SCI,LA JOLLA,CA 92093. MIT,CTR SPACE RES,CAMBRIDGE,MA 02139. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20741. RI Jahoda, Keith/D-5616-2012 NR 24 TC 82 Z9 83 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP L57 EP L60 DI 10.1086/310419 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA684 UT WOS:A1997WA68400015 ER PT J AU Israel, GL Stella, L Angelini, L White, NE Kallman, TR Giommi, P Treves, A AF Israel, GL Stella, L Angelini, L White, NE Kallman, TR Giommi, P Treves, A TI The discovery of 13 second X-ray pulsations from the hydrogen-depleted subdwarf 06 star binary HD 49798 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries, spectroscopic; pulsars, individual (HD 49798); stars, rotation; subdwarfs; X-rays, stars ID SS-CYGNI; PULSARS AB We have discovered strong similar to 13 s X-ray pulsations in the ROSAT Position Sensitive Proportional Counter light curve of HD 49798, a 1.55 day single-component spectroscopic binary containing a hydrogen-depleted subdwarf O6 star. We find no evidence for period changes during the similar to 4 hr ROSAT pointing. The source X-ray spectrum is extremely soft, with an unabsorbed 0.1-2 keV luminosity of a few times 10(32) ergs s(-1) (distance of 650 pc). A higher luminosity might be hidden in the EUV. Our results imply that the unseen companion is an accreting degenerate star, a white dwarf, or, more likely, a neutron star. In any case, HD 49798 corresponds to a previously unobserved evolutionary stage of a massive binary system after the common-envelope phase and spiraling in. C1 INT CTR RELATIVIST ASTROPHYS,ROME,ITALY. OSSERV ASTRON ROMA,I-00040 MONTE PORZIO CATO,ROMA,ITALY. NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,GREENBELT,MD 20771. NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,UNIV SPACE RES ASSOC,HUNTSVILLE,AL 35812. ASI,SAX SCI DATA CTR,I-00198 ROME,ITALY. RP Israel, GL (reprint author), SCH ADV INT STUDIES,VIA BEIRUT 2-4,I-34014 TRIESTE,ITALY. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 28 TC 36 Z9 36 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP L53 EP L56 DI 10.1086/310418 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA684 UT WOS:A1997WA68400014 ER PT J AU Sweigart, AV AF Sweigart, AV TI Effects of helium mixing on the evolution of globular cluster stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE globular clusters, general; stars, abundances; stars, evolution; stars, horizontal-branch; stars, interiors; stars,; population II ID RED GIANT STARS; HORIZONTAL-BRANCH; ABUNDANCES; PHOTOMETRY; ANOMALIES; NGC-6397; CARBON; FIELD; M10; AGE AB New noncanonical sequences for the evolution of globular cluster stars have been computed in order to investigate the effects of mixing helium from the hydrogen shell into the envelope during the red giant branch (RGB) phase. The possible occurrence of such mixing, driven by internal rotation, is suggested by the observed abundance variations involving C, N, O, Na, and Al in globular cluster red giants. We find that helium mixing can substantially increase the envelope helium abundance. By increasing the RGB tip luminosity, helium mixing also leads to enhanced mass loss along the RGB. Both of these effects have a potentially large impact on the subsequent horizontal-branch (HB) evolution. In particular, helium mixing produces a bluer HB morphology, thereby making it easier to explain the hot HB population found in various stellar systems, as well as the difference in HB morphology between some second parameter pairs of globular clusters. Helium-mixed sequences show a larger RR Lyrae period shift and predict a smaller age for the metal-poor globular clusters. In addition, such sequences can reproduce the low gravities observed in blue HB stars. RP Sweigart, AV (reprint author), NASA, GODDARD SPACE FLIGHT CTR, ASTRON & SOLAR PHYS LAB, CODE 681, GREENBELT, MD 20771 USA. NR 38 TC 143 Z9 143 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 1997 VL 474 IS 1 BP L23 EP L26 DI 10.1086/310414 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WA684 UT WOS:A1997WA68400006 ER PT J AU Bergeron, P Ruiz, MT Leggett, SK AF Bergeron, P Ruiz, MT Leggett, SK TI The chemical evolution of cool white dwarfs and the age of the local galactic disk SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE stars, abundances; stars, atmospheres; stars, evolution; stars, fundamental parameters; white dwarfs ID TIME-DEPENDENT CALCULATIONS; METAL ABUNDANCE PATTERNS; DOUBLE-DEGENERATE BINARY; LOW-MASS STARS; INFRARED PHOTOMETRY; ATMOSPHERIC COMPOSITION; LUMINOSITY FUNCTION; MODEL ATMOSPHERES; OPTICAL-SPECTRA; STANDARD STARS AB Photometric and spectroscopic observations of 110 cool white dwarf stars are presented and analyzed with state-of-the-art model atmosphere calculations appropriate for cool white dwarfs with pure hydrogen and pure helium, as well as mixed H/He compositions. High signal-to-noise spectroscopy reveals the presence of H alpha in 20 white dwarfs previously classified as DC stars, four of which are magnetic. Cool white dwarfs are shown to form a narrow sequence in both color-color and color-magnitude diagrams, with little evidence for separation between hydrogen- and helium-rich compositions in these diagrams. The observed energy distributions are obtained from a combination of both optical BVRI and infrared JHK photometric data and used to derive both the effective temperature and the atmospheric composition of each star. Stellar masses are also obtained for 60 white dwarfs with known trigonometric parallaxes. Some discrepancies between the observed energy distributions and those predicted by the model atmospheres are described. In particular, evidence for the presence of a UV opacity source in the coolest hydrogen-rich white dwarfs is interpreted in terms of a pseudo continuum opacity originating from the Lyman edge. The simultaneous analysis of the photometric and spectroscopic observations provides a detailed picture of the chemical composition of cool white dwarfs. Most cool white dwarfs have energy distributions that are well reproduced by either pure hydrogen or pure helium models, with little evidence for objects with mixed atmospheric compositions. We identify a peculiar class of non-DA star with T-eff > 6000 K whose energy distributions are well reproduced by pure hydrogen models but whose spectra do not show Ha. Our results reveal an inhomogeneous temperature distribution of hydrogen- and helium-rich white dwarfs, and in particular the presence of a non-DA gap in the range 5000 less than or similar to T-eff less than or similar to 6000 K. The chemical evolution of cool white dwarfs is discussed at length with respect to our findings. We show that no known physical mechanisms (e.g., convective mixing, convective dredge-up, accretion from the interstellar medium) can account for the temperature distribution of hydrogen- and helium-rich white dwarfs. Possible new mechanisms that could explain our results are presented. We propose a mechanism by which hydrogen is accreted onto the surface of helium-rich white dwarfs while remaining spectroscopically invisible. Observational evidence that supports our hypothesis is discussed. Lower limits for the age of the local Galactic disk are obtained by determining the age of the oldest white dwarfs in our sample. Ages in the range 6.5-10 Gyr are derived from evolutionary models with various core compositions and helium envelope masses. C1 UNIV MONTREAL,DEPT PHYS,MONTREAL,PQ H3C 3J7,CANADA. UNIV CHILE,DEPT ASTRON,SANTIAGO,CHILE. NASA,INFRARED TELESCOPE FACIL,HILO,HI 96720. RI Ruiz, Maria Teresa/I-5770-2016; OI Ruiz, Maria Teresa/0000-0002-6799-1537; Leggett, Sandy/0000-0002-3681-2989 NR 107 TC 208 Z9 209 U1 0 U2 3 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 JAN PY 1997 VL 108 IS 1 BP 339 EP 387 DI 10.1086/312955 PG 49 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WJ100 UT WOS:A1997WJ10000010 ER PT J AU Lakhina, GS Verheest, F AF Lakhina, GS Verheest, F TI Alfvenic solitons in ultrarelativistic electron-positron plasmas SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article ID ELECTROMAGNETIC-WAVES; PULSAR RADIATION; CRAB-NEBULA; FIELD; MODES AB In electron-positron plasmas some of the plasma modes are decoupled due to the equal charge-to-mass ratio of both species. We derive the dispersion law for a low-frequency, generalized X-mode, which exists at all angles of propagation with respect to the static magnetic field. Its nonlinear evolution is governed by a Korteweg-de Vries equation, valid at all angles of propagation except strictly parallel propagation, for which a different approach leads to a vector form of the modified Korteweg-de Vries equation. The nonlinearity is strongest at perpendicular propagation. Ultrarelativistic effects are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. State Univ Ghent, Sterrenkundig Observ, B-9000 Ghent, Belgium. RP Lakhina, GS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lakhina, Gurbax /C-9295-2012; OI Lakhina, Gurbax /0000-0002-8956-486X NR 24 TC 34 Z9 34 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1997 VL 253 IS 1 BP 97 EP 106 DI 10.1023/A:1000523722961 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZH315 UT WOS:000073095400010 ER PT J AU Tielens, AGGM AF Tielens, AGGM TI Circumstellar PAHS and carbon stardust SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on Dust and Molecules in Evolved Stars CY MAR 24-27, 1997 CL UMIST, MANCHESTER, ENGLAND HO UMIST AB The SWS on ISO has revealed the incredible richness of IR emission features in the spectra of post-AGE objects and planetary nebulae. Besides the well known features at 3.3, 6.2, 7.7, 8.6, and 11.3 mu m, a wealth of weaker features is present as well. These studies also reveal detailed variations from source to source, which may be of key importance in the molecular identification process. The emission from Polycyclic Aromatic Hydrocarbon molecules and carbon dust are contrasted with an emphasis on the expected temperature and the feature-to-continuum ratio. Graphite stardust, isolated from carbonaceous meteorites, consist of a core of microcrystalline aromatic moieties mantled by crystalline graphite. This structure suggests the importance of two distinct growth stages or processes. The cores resemble terrestrial soot and indicate formation at relatively low temperature where kinetic factors played an important role, presumably involving PAH formation through reactions of C2H2 and its radical progeny, followed by coagulation of these PAHs as well as further chemical growth. The mantle seems to reflect slow chemical growth at higher temperatures of relatively few PAHs accreted onto these cores. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Tielens, AGGM (reprint author), NASA, Ames Res Ctr, MS245-3, Moffett Field, CA 94035 USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1997 VL 251 IS 1-2 BP 1 EP 13 DI 10.1023/A:1000738212955 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU829 UT WOS:000071760200002 ER PT J AU Glinski, RJ Nuth, JA AF Glinski, RJ Nuth, JA TI Can the red rectangle molecular emission bands be assigned to C-3? SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article ID DIFFUSE INTERSTELLAR BANDS; JET-COOLED-C3; FLUORESCENCE; SPECTROSCOPY; RADIATION; HD-44179; CARRIERS; SPECTRUM; MATRIX; IONS AB We review the current information on the unique group of visible emission bands known as the Red Rectangle bands (RRBs). A laboratory spectrum exactly matching these bands is not yet available; however, there is sufficient reason to hypothesize phosphorescence from C-3 as the source. The points in favor of the C-3/RRB hypothesis can be summarized as follows: (1) The RRBs are found in the spatial location where carbonaceous grains are being impinged upon by a bipolar outflow. (2) C-3 is known to accompany circumstellar carbon grains and may constitute a 'magic' fragment in the UV photofragmentation of C-n clusters. (3) Our recent observation of the spin-forbidden CO Cameron emission bands in this object suggests that charged particle impact excites triplet states. (4) The energy of the lowest triplet state of C-3 is known to be very close to that of the RRBs. (5) The RRBs display a vibrational spacing that is quantitatively consistent with C-3, including a rare negative anharmonicity. C1 TENNESSEE TECHNOL UNIV,DEPT CHEM,COOKEVILLE,TN 38505. RP Glinski, RJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ASTROCHEM BRANCH,CODE 691,GREENBELT,MD 20771, USA. RI Nuth, Joseph/E-7085-2012 NR 34 TC 9 Z9 9 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1997 VL 249 IS 1 BP 143 EP 149 DI 10.1023/A:1000355313422 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YB897 UT WOS:A1997YB89700011 ER PT J AU Baykal, A Kiziloglu, U AF Baykal, A Kiziloglu, U TI Low frequency flickering of TT Arietis: Hard and soft X-ray emission region SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article DE binaries, close; stars, individual (TT Arietis); stars, cataclysmic variables; X-rays, stars ID TIME-SERIES ANALYSIS; MAIN-SEQUENCE; SPACED DATA; EX-HYDRAE; STARS; ASCA; OSCILLATIONS; VARIABILITY; SPECTRUM; STATE AB Using archival ASCA observations of TT Arietis, X-ray energy spectra and power spectra of the intensity time series are presented for the first time. The energy spectra are well-fitted by a two continuum plasma emission model with temperatures similar to 1 keV and similar to 10 keV. A coherent feature at similar to 0.643 mHz appeared in the power spectra during the observation. C1 NASA,GODDARD SPACE FLIGHT CTR,HIGH ENERGY ASTROPHYS LAB,NRC,GREENBELT,MD 20771. RP Baykal, A (reprint author), MIDDLE E TECH UNIV,DEPT PHYS,TR-06531 ANKARA,TURKEY. NR 28 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 1997 VL 246 IS 1 BP 29 EP 38 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XL086 UT WOS:A1997XL08600004 ER PT B AU Silverberg, RF AF Silverberg, RF CA MSAM TopHat Collaboration BE Novak, G Landsberg, RH TI The TopHat Cosmic Microwave Background anisotropy experiments SO ASTROPHYSICS FROM ANTARCTICA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT ASP Summer Scientific Symposium Conference on Astrophysics from Antarctica CY JUN 30-JUL 02, 1997 CL CHICAGO, IL SP Astron Soc Pacific, Natl Sci Fdn, Ctr Astrophys Res Antarctica AB We have developed a program of complementary balloon-borne experiments to measure the Cosmic Microwave Background Radiation anisotropy on angular scales from similar to 50 degrees down to similar to 20'. The instruments observe at frequencies between 150 and 690 GHz and one of them will be flown on an Antarctic circumpolar long duration flight. With high sensitivity, large sky coverage, and well-characterized systematic errors, the results of this program can be used to strongly constrain cosmological models and probe the early stages of large-scale structure formation in the Universe. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Silverberg, RF (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-61-9 J9 ASTR SOC P PY 1997 VL 141 BP 97 EP 105 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74N UT WOS:000076534200010 ER PT B AU Sandford, SA AF Sandford, SA BE Novak, G Landsberg, RH TI Meteorites on ice: Collecting primitive solar system materials in Antarctica SO ASTROPHYSICS FROM ANTARCTICA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT ASP Summer Scientific Symposium Conference on Astrophysics from Antarctica CY JUN 30-JUL 02, 1997 CL CHICAGO, IL SP Astron Soc Pacific, Natl Sci Fdn, Ctr Astrophys Res Antarctica AB The study of non-terrestrial Solar System materials yields important clues about the environments and processes operant during the formation of the Solar System and subsequent parent body evolution. In addition, because the more primitive forms of these materials contain relic interstellar grains, they also provide quantitative information about stellar nucleosynthesis and the chemical and physical processes that occur in the interstellar medium. Primitive materials are made available to us in the form of cosmic dust and meteorites that impact the Earth. Meteorites fall uniformly on the surface of the planet, but for reasons that will be discussed in this paper, Antarctica turns out to be the best place on Earth to find and collect them. At this point, the number of meteorites collected in Antarctica rivals the total number collected from the rest of the world. Important samples collected from Antarctica include a number of unique specimens including multiple meteorites from both the Moon and Mars. C1 NASA, Ames Res Ctr, Astrophys Branch, Moffett Field, CA 94035 USA. RP Sandford, SA (reprint author), NASA, Ames Res Ctr, Astrophys Branch, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-61-9 J9 ASTR SOC P PY 1997 VL 141 BP 265 EP 282 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74N UT WOS:000076534200029 ER PT B AU Israel, DJ AF Israel, DJ BE Novak, G Landsberg, RH TI The South Pole TDRSS Relay (SPTR) SO ASTROPHYSICS FROM ANTARCTICA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT ASP Summer Scientific Symposium Conference on Astrophysics from Antarctica CY JUN 30-JUL 02, 1997 CL CHICAGO, IL SP Astron Soc Pacific, Natl Sci Fdn, Ctr Astrophys Res Antarctica AB During the 1997/1998 season, the NASA Goddard Space Flight Center will be installing the South Pole TDRSS Relay (SPTR) at the South Pole. SPTR will provide high data rate communications with the South Pole using the NASA Tracking and Data Relay Satellite System (TDRSS). The following is a brief description of the SPTR communications services. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Israel, DJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-61-9 J9 ASTR SOC P PY 1997 VL 141 BP 319 EP 321 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74N UT WOS:000076534200035 ER PT B AU Werner, M AF Werner, M BE Novak, G Landsberg, RH TI SIRTF: A status report & implications for Antarctic observatories SO ASTROPHYSICS FROM ANTARCTICA SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT ASP Summer Scientific Symposium Conference on Astrophysics from Antarctica CY JUN 30-JUL 02, 1997 CL CHICAGO, IL SP Astron Soc Pacific, Natl Sci Fdn, Ctr Astrophys Res Antarctica AB This paper summarizes the characteristics and status of SIRTF - the Space Infrared Telescope Facility. SIRTF will be a cryogenically-cooled space telescope instrumented with large-format, state of the art monolithic infrared detector arrays. SIRTF will complete NASA's family of Great Observatories and also serve as the first major scientific and technical step in the Origins program. It will be launched in 2001, carrying a complement of imaging and spectroscopic instrumentation. More than 75% of the observing time on SIRTF will be available to the general scientific community. SIRTF is a member of a family of cryogenic telescopes for space infrared astronomy whose patriarch was IRAS which includes COBE, ISO and WIRE. The general characteristics of these space missions are discussed; they should be borne in mind as potential facilities for infrared astronomy from Antarctica are evaluated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Werner, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-61-9 J9 ASTR SOC P PY 1997 VL 141 BP 325 EP 332 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74N UT WOS:000076534200036 ER PT J AU Feikema, DA Eskridge, R Hutt, JJ AF Feikema, DA Eskridge, R Hutt, JJ TI Structure of a nonevaporating swirl injector spray SO ATOMIZATION AND SPRAYS LA English DT Article AB The structure of a dense-liquid, swirl-injector, hollow-cone spray operating in atmospheric pressure conditions has been investigated using strobe photography, phase Doppler particle anemometry, (PDPA), and mechanical liquid collection methods. Image-processed strobe photographs and measurements of drop velocity, drop size, and liquid mass flux in the dense spray of a pressure-swirl, hollow-cone liquid oxygen (LOX) simulant injector are reported, as well as analysis resulting from these measurements. Since combusting liquid sprays depend on the liquid dispersion rates and the size and distribution of the drops, the liquid mass distribution is important in evaluating the performance of a liquid rocket engine spray. The objective of this study was to determine the drop velocity, the drop size and distribution, the liquid mass distribution within the spray, and a possible relationship to the internal flow of the injector. The results demonstrate that accurate mass flux measurements can be made with the PDPA but only within the discrete droplet regions of the dense spray, which for the present conditions occurs between 20 and 30 injector exit diameters from the injector exit. The measured mean drop size is approximately 330 mu m in the dense portion of the spray, which is considerably less than the predicted analytic mean diameter of 1150 mu m. The breakup mechanism used to derive the analytic mean drop size expression is qualitatively correct, but it overpredicts the mean drop size because the method does not account correctly for injection-induced turbulence within the liquid sheet and wind-induced secondary breakup, which are important in high-velocity liquid atomization. The results reaffirm that the conical liquid sheet thickness is an important parameter in drop size determination. C1 NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,HUNTSVILLE,AL 35812. RP Feikema, DA (reprint author), UNIV ALABAMA,PROPULS RES CTR,DEPT MECH & AEROSP ENGN,HUNTSVILLE,AL 35899, USA. NR 17 TC 8 Z9 8 U1 0 U2 1 PU BEGELL HOUSE INC PI NEW YORK PA 79 MADISON AVE, SUITE 1205, NEW YORK, NY 10016-7892 SN 1044-5110 J9 ATOMIZATION SPRAY JI Atom. Sprays PD JAN-FEB PY 1997 VL 7 IS 1 BP 77 EP 95 PG 19 WC Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA WY348 UT WOS:A1997WY34800004 ER PT B AU Caldwell, JL AF Caldwell, JL GP IEEE COMP SOC TI Moving proofs-as-programs into practice SO AUTOMATED SOFTWARE ENGINEERING, 12TH IEEE INTERNATIONAL CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 12th IEEE International Conference on Automated Software Engineering (ASE 97) CY NOV 01-05, 1997 CL INCLINE VILLAGE, NV SP IEEE Comp Soc, NASA Ames Res Ctr, AAAI, ACM SIGART, ACM SIGSOFT, Microsoft AB Proofs in the Nuprl system, an implementation of a constructive type theory, yield ''correct-by-consrtuction'' programs In this paper a new methodology is presented for extracting efficient and readable programs from inductive proofs. The resulting extracted programs are in a form suitable for use in hierarchical verifications in that they are amenable to clean partial evaluation via extensions to the Nuprl rewrite system. The method is bused on two elements specifications written with careful use of the Nuprl set-type to restrict the extracts to strictly computational content; and on proofs that use induction tactics that generate extracts using familiar fixed-point combinators of the untyped lambda calculus. In this paper the methodology is described and its application is illustrated example. RP Caldwell, JL (reprint author), NASA,AMES RES CTR,COMPUTAT SCI DIV,MAIL STOP 269-1,MOFFETT FIELD,CA 94035, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU I E E E, COMPUTER SOC PRESS PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, LOS ALAMITOS, CA 90720 BN 0-8186-7962-X PY 1997 BP 10 EP 17 DI 10.1109/ASE.1997.632819 PG 2 WC Computer Science, Software Engineering SC Computer Science GA BK01R UT WOS:A1997BK01R00007 ER PT B AU Udomkesmalee, S Thakoor, A Padgett, C Daud, T Fang, WC Suddarth, SC AF Udomkesmalee, S Thakoor, A Padgett, C Daud, T Fang, WC Suddarth, SC BE Sadjadi, FA TI VIGILANTE: An advanced sensing/processing testbed for ATR applications SO AUTOMATIC TARGET RECOGNITION VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Automatic Target Recognition VII CY APR 22-24, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE automatic target recognition; neural processor; multispectral sensors; system architecture AB VIGILANTE consists of two major components: 1) the Viewing Imager/Gimballed Instrumentation Laboratory (VIGIL)-advanced infrared, visible, and ultraviolet sensors with appropriate optics and camera electronics 2) the Analog Neural Three-dimensional processing Experiment (ANTE)-a massively parallel, neural network-based, high-speed processor. The powerful combination of VIGIL and ANTE will provide real-time target recognition/tracking capability suitable for Ballistic Missile Defense Organization (BMDO) applications as well as a host of other civil and military uses. In this paper, we describe VIGILANTE and its application to typical automatic target recognition (ATR) applications (e.g., aircraft/missile detection, classification, and tracking), this includes a discussion of the VIGILANTE architecture with its unusual blend of experimental 3D electronic circuitry, custom design and commercial parallel processing components, as well as VIGILANTE's ability to handle a wide variety of algorithms which make extensive use of convolutions and neural networks. Our paper also presents examples and numerical results. RP Udomkesmalee, S (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2484-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3069 BP 82 EP 93 DI 10.1117/12.277145 PG 12 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BJ16U UT WOS:A1997BJ16U00008 ER PT B AU Wallace, RG Affens, DW Rais, H AF Wallace, RG Affens, DW Rais, H BE Sadjadi, FA TI Beaconless search and rescue overview - History, development, and achievements SO AUTOMATIC TARGET RECOGNITION VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Automatic Target Recognition VII CY APR 22-24, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE synthetic aperture radar; search and rescue; automatic target recognition; foliage penetration AB NASA Search and Rescue Mission at Goddard Space Flight Center (GSFC) is carrying out a technology development project intended to complement the COSPAS-SARSAT satellite-based distress alerting and locating system. This system is based on emergency radio beacons and cannot function when beacons fail to operate. The beaconless search and rescue concept utilizes an airborne or spaceborne remote sensing instrument, such as a synthetic aperture radar (SAR), to aid in searching for downed aircraft in remote regions when no beacon is present. Compared with conventional visual search, a radar-based system would be capable of dramatically improving crash site detection due to its wide area coverage and foliage penetration. Moreover, the performance of this system is unaffected by weather conditions and ambient light level and hence it offers quick response time which is vital to the survival of crash victims. The Search and Rescue Mission has conducted a series of field experiments using the Jet Propulsion Laboratory's airborne SAR system (AIRSAR) which have demonstrated the technical feasibility of using SAR. The SAR Data Processing Software (SARDPS) developed at GSFC is used to produce high-quality SAR images for post-processing and analysis. Currently various elements of an operational system are king investigated, including a SAR designed specifically to meet search and rescue needs, real-time or near real-time on-board SAR processing, and processing algorithms for advanced automatic crash site detection, image gee-rectification and map registration. RP Wallace, RG (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 7 Z9 7 U1 1 U2 1 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2484-6 J9 P SOC PHOTO-OPT INS PY 1997 VL 3069 BP 162 EP 166 DI 10.1117/12.277101 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BJ16U UT WOS:A1997BJ16U00016 ER PT J AU Cao, YU Fukunaga, AS Kahng, AB AF Cao, YU Fukunaga, AS Kahng, AB TI Cooperative mobile robotics: Antecedents and directions SO AUTONOMOUS ROBOTS LA English DT Article DE cooperative robotics; swarm intelligence; distributed robotics; artificial intelligence; mobile robots; multiagent systems ID TRAFFIC REGULATION; SYSTEM; COMMUNICATION; ARCHITECTURE; OBJECT; TASK AB There has been increased research interest in systems composed of multiple autonomous mobile robots exhibiting cooperative behavior. Groups of mobile robots are constructed, with an aim to studying such issues as group architecture, resource conflict, origin of cooperation, learning, and geometric problems. As yet, few applications of cooperative robotics have been reported, and supporting theory is still in its formative stages. In this paper, we give a critical survey of existing works and discuss open problems in this field, emphasizing the various theoretical issues that arise in the study of cooperative robotics. We describe the intellectual heritages that have guided early research, as well as possible additions to the set of existing motivations. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP UNIV CALIF LOS ANGELES, DEPT COMP SCI, LOS ANGELES, CA 90024 USA. NR 188 TC 430 Z9 454 U1 7 U2 52 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 EI 1573-7527 J9 AUTON ROBOT JI Auton. Robot. PY 1997 VL 4 IS 1 BP 7 EP 27 DI 10.1023/A:1008855018923 PG 21 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA WV846 UT WOS:A1997WV84600002 ER PT J AU MacKenzie, DC Arkin, RC Cameron, JM AF MacKenzie, DC Arkin, RC Cameron, JM TI Multiagent mission specification and execution SO AUTONOMOUS ROBOTS LA English DT Article DE autonomous robotics; mission specification; visual programming ID MOBILE ROBOT NAVIGATION; SYSTEMS AB Specifying a reactive behavioral configuration for use by a multiagent team requires both a careful choice of the behavior set and the creation of a temporal chain of behaviors which executes the mission. This difficult task is simplified by applying an object-oriented approach to the design of the mission using a construction called an assemblage and a methodology called temporal sequencing. The assemblage construct allows building high level primitives which provide abstractions for the designer. Assemblages consist of groups of basic behaviors and coordination mechanisms that allow the group to be treated as a new coherent behavior. Upon instantiation, the assemblage is parameterized based on the specific mission requirements. Assemblages can be re-parameterized and used in other states within a mission or archived as high level primitives for use in subsequent projects. Temporal sequencing partitions the mission into discrete operating states with perceptual triggers causing transitions between those states. Several smaller independent configurations (assemblages) can then be created which each implement one state. The Societal Agent theory is presented as a basis for constructions of this form. The Configuration Description Language (CDL) is developed to capture the recursive composition of configurations in an architecture- and robot-independent fashion. The MissionLab system(1), an implementation based on CDL, supports the graphical construction of configurations using a visual editor. Various multiagent missions are demonstrated in simulation and on our Denning robots using these tools. C1 CALTECH, JET PROP LAB, PASADENA, CA 91109 USA. RP MacKenzie, DC (reprint author), GEORGIA INST TECHNOL, COLL COMP, MOBILE ROBOT LAB, ATLANTA, GA 30332 USA. NR 51 TC 102 Z9 104 U1 0 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 J9 AUTON ROBOT JI Auton. Robot. PY 1997 VL 4 IS 1 BP 29 EP 52 DI 10.1023/A:1008807102993 PG 24 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA WV846 UT WOS:A1997WV84600003 ER PT J AU Weisbin, CR Lavery, DB Rodriguez, G AF Weisbin, CR Lavery, DB Rodriguez, G TI Robots in space: US missions and technology requirements into the next century SO AUTONOMOUS ROBOTS LA English DT Article DE robotics; rovers; planetary exploration; in-orbit servicing; robot autonomy; sample acquisition; dexterous manipulation; sample return AB The Telerobotics Program of the National Aeronautics and Space Administration (NASA) Office of Space Science is developing innovative telerobotics technologies to enable or support a wide range of space missions over the next decade and beyond. These technologies fall into four core application areas: landers, surface vehicles (revers), and aerovehicles for solar system exploration and science; revers for commercially supported lunar activities; free-flying and platform-attached robots for in-orbit servicing and assembly; and robots supporting in-orbit biotechnology and microgravity experiments. Such advanced robots will enable missions to explore Mars, Venus, and Saturn's moon Titan, as well as probes to sample comets and asteroids. They may also play an important role in commercially funded exploration of large regions on Earth's Moon, as well as the eventual development of a human-supporting Lunar Outpost. In addition, in-orbit servicing of satellites and maintenance of large platforms like the International Space Station will require extensive robotics capabilities. C1 NASA, OFF SPACE ACCESS & TECHNOL, WASHINGTON, DC 20546 USA. RP CALTECH, JET PROP LAB, 4800 OAK GROVE DR, PASADENA, CA 91109 USA. NR 18 TC 3 Z9 3 U1 1 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 EI 1573-7527 J9 AUTON ROBOT JI Auton. Robot. PY 1997 VL 4 IS 2 BP 159 EP 173 DI 10.1023/A:1008808730915 PG 15 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA XG875 UT WOS:A1997XG87500001 ER PT B AU Calhoun, CC AF Calhoun, CC GP IEEE TI Applying independent verification & validation to ATE SO AUTOTESTCON '97 - IEEE SYSTEMS READINESS TECHNOLOGY CONFERENCE, 1997 IEEE AUTOTESTCON PROCEEDINGS LA English DT Proceedings Paper CT IEEE Systems Readiness Technology Conference (AUTOTESTCON 97) CY SEP 22-25, 1997 CL ANAHEIM, CA SP IEEE, Aerosp & Electr Syst Soc, Instrumentat & Measurement Soc, IEEE, Los Angeles Council AB This paper describes a general overview of applying Independent Verification and Validation (IV&V) to Automatic Test Equipment (ATE). The overview is not inclusive of all IV&V activities that can occur or of all development and maintenance items that can be validated and verified, during the IV&V process. A sampling of possible IV&V activities that can occur within each phase of the ATE life cycle are described. RP Calhoun, CC (reprint author), NASA,SOFTWARE INDEPENDENT VERIFICAT & VALIDAT FACIL,100 UNIV DR,FAIRMONT,WV 26554, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 BN 0-7803-4162-7 PY 1997 BP 285 EP 289 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BJ71J UT WOS:A1997BJ71J00042 ER PT J AU Styf, JR Ballard, RE Fechner, K Watenpaugh, DE Kahan, NJ Hargens, AR AF Styf, JR Ballard, RE Fechner, K Watenpaugh, DE Kahan, NJ Hargens, AR TI Height increase, neuromuscular function, and back pain during 6 degrees head-down tilt with traction SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article ID ERECTOR SPINAE MUSCLE; FLUID SHIFTS; MICROGRAVITY; EXERCISE AB Background: Spinal lengthening and back pain are commonly experienced by astronauts exposed to microgravity. Methods: To develop a ground-based simulation for spinal adaptation to microgravity, we investigated height increase, neuromuscular function and back pain in 6 subjects all of whom underwent two forms of bed rest for 3 d. One form consisted of 6 degrees of head-down tilt (HDT) with balanced traction, while the other was horizontal bed rest (HER). Subjects had a 2-week recovery period in between the studies. Results: Total body and spinal length increased significantly more and the subjects had significantly more back pain during HDT with balanced traction compared to HER. The distance between the lower endplate of L4 and upper endplate of S1, as measured by ultrasonography, increased significantly in both treatments to the same degree. Intramuscular pressures in the erector spinae muscles and ankle torque measurements during plantarflexion and dorsiflexion did not change significantly during either treatment. Conclusion: Compared to HER, HDT with balanced traction may be a better method to simulate changes of total body and spinal lengths, as well as back pain seen in microgravity. C1 NASA,AMES RES CTR,GRAVITAT RES BRANCH,MOFFETT FIELD,CA 94035. NR 25 TC 21 Z9 22 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 JAN PY 1997 VL 68 IS 1 BP 24 EP 29 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA WD145 UT WOS:A1997WD14500005 PM 9006878 ER PT S AU Buchanan, JT AF Buchanan, JT BE Duncan, JR Johnson, DH Nicholls, TH TI A spatial analysis of the burrowing owl (Speotyto cunicularia) population in Santa Clara County, California, using a geographic information system SO BIOLOGY AND CONSERVATION OF OWLS OF THE NORTHERN HEMISPHERE SE USDA FOREST SERVICE GENERAL TECHNICAL REPORT NORTH CENTRAL LA English DT Proceedings Paper CT 2nd International Symposium on Biology and Conservation of Owls of the Northern Hemisphere CY FEB 05-09, 1997 CL WINNIPEG, CANADA SP USDA, Washington Dept Fish & Wildlife, US Dept Interior, US Fish & Wildlife Serv, US Dept Interior, Bur Land Management, Manitoba Nat Resources, Environm Canada AB A small population of Burrowing Owls (Speotyto cunicularia) is found in the San Francisco Bay Area, particularly in Santa Clara County. These owls utilize habitat that is dispersed throughout this heavily urbanized region. In an effort to establish a conservation plan for Burrowing Owls in Santa Clara County, a spatial analysis of owl distribution and habitat was performed using remote sensing and geographic information system (GIS) technologies. Land areas that could provide valuable habitat for owls in the future and that could link together groups of owls throughout the region, were identified. C1 NASA, Ames Res Ctr, Johnson Controls World Serv, Moffett Field, CA 94035 USA. RP Buchanan, JT (reprint author), NASA, Ames Res Ctr, Johnson Controls World Serv, MS242, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU US DEPT AGR, FOREST SERV, N CENT RES STN PI ST PAUL PA 1992 FOLWELL AVENUE, ST PAUL, MN 55108 USA SN 0363-616X J9 US FOR SERV T R NC PY 1997 VL 190 BP 90 EP 96 PG 7 WC Ecology; Ornithology; Zoology SC Environmental Sciences & Ecology; Zoology GA BM08A UT WOS:000077557600014 ER PT J AU Greenleaf, JE LooftWilson, R Wisherd, JL McKenzie, MA Jensen, CD Whittam, JH AF Greenleaf, JE LooftWilson, R Wisherd, JL McKenzie, MA Jensen, CD Whittam, JH TI Pre-exercise hypervolemia and cycle ergometer endurance in men SO BIOLOGY OF SPORT LA English DT Article DE fluid intake composition; electrolytes; glucose; citrate; exercise ID FLUID REPLACEMENT; SODIUM-CITRATE; PERFORMANCE; INGESTION; GLYCEROL; TEMPERATURE; GLUCOSE; SALINE; HYPERHYDRATION; DEHYDRATION AB Time to exhaustion at 87 - 91% of peak (V) over dotO(2) was measured in 5 untrained men (age: 31+/-8 years, body mass: 74.20+/-16.50 kg, body surface area: 1.90+/-0.24 m(2), peak (V) over dot O-2: 2.87+/-0.40 l.min(-1), plasma volume: 3.21+/-0.88 l; means +/-SD) after consuming nothing (N) or two fluid formulations (10 ml.kg(-1), 743+/-161 ml). Performance 1 (P1), a multi-ionic carbohydrate drink, containing 55 mEq.l(-1) Na+, 4.16 g.l(-1) citrate, 20.49 g.l(-1) glucose, and 365 mOsm.kg(-1) H2O, and AstroAde (AA), a sodium chloride-sodium citrate hyperhydration drink, containing 164 mEq.l(-1) Na+, 8.54 g.l(-1) citrate, <5 mg.l(-1) glucose, and 253 mOsm.kg(-1) H2O. Mean (+/-SE) endurance for N, P1 and AA was 24.68+/-1.50, 24.55+/-1.09, and 30.50+/-3.44 min, respectively. Percent changes in plasma volume (PV) from -105, min of rest to zero min before exercise were -1.5+/-3.2% (N), 0.2+/-2.2% (P1), and 4.8+/-3.0% (AA; P<0.05). The attenuated endurance for N and P1 could not be attributed to differences in exercise metabolism ((V) over dot E, RE, (V) over dot O-2) from the carbohydrate or citrate, terminal heart rate, levels of perceived exertion, forehead or thigh skin blood flow velocity, changes or absolute termination levels of rectal temperature. Thus, the higher level of resting PV for AA just before exercise, as well as greater acid buffering and possible increased energy substrate from citrate, may have contributed to the seater endurance. C1 SAN FRANCISCO STATE UNIV,SAN FRANCISCO,CA 94132. SHAKLEE TECHNICA,SAN FRANCISCO,CA. RP Greenleaf, JE (reprint author), NASA,AMES RES CTR,GRAVITAT RES BRANCH 239 11,LAB HUMAN ENVIRONM PHYSIOL,MOFFETT FIELD,CA 94035, USA. NR 36 TC 17 Z9 19 U1 0 U2 5 PU INST SPORT PI WARSAW 45 PA TRYLOGII 2, POB 30, 01-892 WARSAW 45, POLAND SN 0860-021X J9 BIOL SPORT JI Biol. Sport PY 1997 VL 14 IS 2 BP 103 EP 114 PG 12 WC Sport Sciences SC Sport Sciences GA XF206 UT WOS:A1997XF20600002 PM 11540419 ER PT B AU Halama, GE McAdoo, JA Liu, H AF Halama, GE McAdoo, JA Liu, H BE VoDinh, T Lieberman, RA Vurek, GG Katzir, A TI Results of scatter reduction mechanism in CCD mosaic concept for digital mammography SO BIOMEDICAL SENSING, IMAGING, AND TRACKING TECHNOLOGIES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Biomedical Sensing, Imaging, and Tracking Technologies II CY FEB 11-13, 1997 CL SAN JOSE, CA SP Int Biomed Opt Soc, Soc Photo Opt Instrumentat Engineers, Amer Soc Laser Med & Surg Inc AB The design of a proposed CCD mosaic concept for digital mammography uses a lead shield with through holes to reduce the patient exposure in regions of the mosaic where there are no CCDs. This shield also has an inherent advantage of reducing the amount of scattered x-rays. We examined the scatter-to-primary ratio dependency with aperture size above and below the breast and air gap distance between the CCD assembly and the bottom of the breast. These results are discussed in regards to the optimization of the CCD mosaic concept and theoretical calculations. RP Halama, GE (reprint author), NASA,LANGLEY RES CTR,MS 468,HAMPTON,VA 23681, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2387-4 J9 P SOC PHOTO-OPT INS PY 1997 VL 2976 BP 262 EP 269 DI 10.1117/12.275547 PG 8 WC Engineering, Biomedical; Optics; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Optics; Radiology, Nuclear Medicine & Medical Imaging GA BJ12R UT WOS:A1997BJ12R00029 ER PT B AU Hubeny, I Heap, SR Lanz, T AF Hubeny, I Heap, SR Lanz, T BE Howarth, ID TI Non-LTE line-blanketed model atmospheres of O stars SO BOULDER-MUNICH II: PROPERTIES OF HOT, LUMINOUS STARS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 2nd Boulder-Munich Workshop on Properties of Hot Luminous Stars CY JUL 21-24, 1997 CL CUMBERLAND LODGE, BOULDER, CO HO CUMBERLAND LODGE AB A brief review of the recent progress in model atmospheres for hot stars is presented. We show that, since departures from LTE as well as the effects of metal-line blanketing are very important, one has to construct fully blanketed non-LTE model atmospheres for these objects. We show that the recent progress in the fast numerical methods, namely those based on the Accelerated Lambda Iteration, has led to an enormous progress in the degree of realism in computed model atmospheres. The importance and the power of the new model atmospheres is illustrated on an analysis of HST/GHRS observations of the main-sequence O9 V star 10 Lac. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hubeny, I (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI heap, sara/E-2237-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-51-1 J9 ASTR SOC P PY 1997 VL 131 BP 108 EP 118 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK81A UT WOS:000073467200011 ER PT B AU Massa, D Prinja, RK AF Massa, D Prinja, RK BE Howarth, ID TI A UV survey of B supergiants: Continuum properties SO BOULDER-MUNICH II: PROPERTIES OF HOT, LUMINOUS STARS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 2nd Boulder-Munich Workshop on Properties of Hot Luminous Stars CY JUL 21-24, 1997 CL CUMBERLAND LODGE, BOULDER, CO HO CUMBERLAND LODGE AB We report our ongoing investigation into the photospheric properties of B supergiants. We review the spectroscopic diagnostics which make the B supergiants ideal for several types of studies; and then discuss initial progress made in determining their intrinsic flux distributions. We also include a discussion of LTE model parameters and our plans for producing a uniform high-dispersion data base. C1 NASA, Goddard Space Flight Ctr, Hughes STX, Greenbelt, MD 20771 USA. RP Massa, D (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-51-1 J9 ASTR SOC P PY 1997 VL 131 BP 208 EP 217 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK81A UT WOS:000073467200022 ER PT J AU Huffman, GJ Adler, RF Arkin, P Chang, A Ferraro, R Gruber, A Janowiak, J McNab, A Rudolf, B Schneider, U AF Huffman, GJ Adler, RF Arkin, P Chang, A Ferraro, R Gruber, A Janowiak, J McNab, A Rudolf, B Schneider, U TI The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SENSOR MICROWAVE IMAGER; PROBABILITY-DISTRIBUTION FUNCTIONS; SEA-SURFACE TEMPERATURE; SOUTHERN OSCILLATION; EL-NINO; MONTHLY RAINFALL; ENSO EPISODE; SSM/I; VARIABILITY; RETRIEVAL AB The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 degrees x 2.5 degrees latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies. C1 SCI SYST & APPLICAT INC,GREENBELT,MD. NOAA,NWS,NATL CTR ENVIRONM PREDICT,CAMP SPRINGS,MD. NASA,GODDARD SPACE FLIGHT CTR,LAB HYDROSPHER PROC,GREENBELT,MD 20771. NOAA,NESDIS,OFF RES & APPLICAT,CAMP SPRINGS,MD. NOAA,NESDIS,NATL CLIMAT DATA CTR,ASHEVILLE,NC. DEUTSCH WETTERDIENST,GLOBAL PRECIPITAT CLIMATOL CTR,OFFENBACH,GERMANY. RP Huffman, GJ (reprint author), NASA,GODDARD SPACE FLIGHT CTR,ATMOSPHERES LAB,CODE 912,GREENBELT,MD 20771, USA. RI Arkin, Phillip/F-5808-2010; Huffman, George/F-4494-2014; Ferraro, Ralph/F-5587-2010 OI Huffman, George/0000-0003-3858-8308; Ferraro, Ralph/0000-0002-8393-7135 NR 40 TC 937 Z9 990 U1 5 U2 56 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JAN PY 1997 VL 78 IS 1 BP 5 EP 20 DI 10.1175/1520-0477(1997)078<0005:TGPCPG>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WJ825 UT WOS:A1997WJ82500001 ER PT S AU Hilsenrath, E Bhartia, PK Cebula, RP Wellemeyer, CG AF Hilsenrath, E Bhartia, PK Cebula, RP Wellemeyer, CG BE Tsuchiya, K TI Calibration and intercalibration of backscatter ultraviolet (BUV) satellite ozone data SO CALIBRATION AND INTERCALIBRATION OF SATELLITE SENSORS AND EARLY RESULTS OF RADARSAT SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A0.3 Symposium of COSPAR Scientific Commission A on Calibration and Intercalibration of Satellite Sensors and Early Results of Radarsat, at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Canadian Space Agcy, CNES, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Serv, Adm, Sci Comm Ocean Res ID NORTHERN-HEMISPHERE; INSTRUMENT; FLIGHT; TRENDS; SSBUV AB Eight TOMS and SBUV ozone instruments have been in orbit since 1978. In addition eight Shuttle SBUV flights have been conducted since 1989. The ESA GOME instrument, using the BUV technique, is flying on ERS-2 since April 1995. At least two more TOMS type instruments will fly on US, Japanese, and Russian environmental satellites. NOAA. will continue flying SBUV instruments on their polar platforms until about the year 2004. Combined satellite and ground based data have verified that global ozone depletion has occurred over the past decade. Confidence in the satellite detected trends results from NASA's comprehensive studies of the various instruments pre- and post- launch calibrations and algorithm refinements. Pre-launch calibrations of BUV type instruments is now standardized using an integrating sphere whose radiance is derived from a NIST irradiance standard. Pre-launch calibrations among several BUV instruments is now consistent to 1-2%. Several techniques are used to characterize and correct instrument long term sensitivity once in orbit. These techniques include: on board calibration systems, spectral discrimination, in-orbit intercomparisons, and scene stabilization. These techniques have been applied to the SBUV, TOMS, and SBUV/2 observations resulting in a data record with trend uncertainty of 1% per decade. Published by Elsevier Science on behalf of COSPAR. C1 HUGHES STX CORP,GREENBELT,MD 20770. RP Hilsenrath, E (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. RI Bhartia, Pawan/A-4209-2016 OI Bhartia, Pawan/0000-0001-8307-9137 NR 21 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043286-7 J9 ADV SPACE RES PY 1997 VL 19 IS 9 BP 1345 EP 1353 DI 10.1016/S0273-1177(97)00243-3 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BJ16G UT WOS:A1997BJ16G00006 ER PT S AU Green, RO Shimada, M AF Green, RO Shimada, M BE Tsuchiya, K TI On-orbit calibration of a multispectral satellite sensor using a high altitude airborne imaging spectrometer SO CALIBRATION AND INTERCALIBRATION OF SATELLITE SENSORS AND EARLY RESULTS OF RADARSAT SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A0.3 Symposium of COSPAR Scientific Commission A on Calibration and Intercalibration of Satellite Sensors and Early Results of Radarsat, at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Canadian Space Agcy, CNES, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Serv, Adm, Sci Comm Ocean Res AB Earth-looking satellite sensors must be calibrated in order to quantitatively measure and monitor components of land, water and atmosphere of the Earth System. The inevitable change in performance due to the stress of satellite launch requires that the calibration of a satellite sensor be established and validated on-orbit. A new approach to on-orbit satellite sensor calibration has been developed using the flight of a high altitude calibrated airborne imaging spectrometer below a multi-spectral satellite sensor. This strategy was implemented on August 27, 1992, for the Optical Sensor (OPS) on board the Japanese Earth Resources Satellite-1 (JERS-1) using NASA's Airborne Visible-Infrared Imaging Spectrometer (AVIRIS). Calibrated AVIRIS spectral radiance data were acquired beneath OPS. OPS has eight spectral filters and eight detector arrays with 4096 elements to measure each of eight spectral bands in the solar reflected spectrum across a 75 km ground swath, AVIRIS data were spectrally convolved and spatially registered to the OPS data in the overlapping image area measured by the two sensors. The convolved and registered AVIRIS radiance data were used to determine the 32,768 on-orbit radiometric calibration coefficients required for calibration of the full 75 km swath and eight spectral bands of OPS. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 UNIV CALIF SANTA BARBARA,INST COMPUTAT EARTH SYST SCI,SANTA BARBARA,CA 93106. NASDA,EARTH OBSERVING CTR,HATOYAMA,SAITAMA,JAPAN. RP Green, RO (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 9 TC 12 Z9 12 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0273-1177 BN 0-08-043286-7 J9 ADV SPACE RES PY 1997 VL 19 IS 9 BP 1387 EP 1398 DI 10.1016/S0273-1177(97)00251-2 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BJ16G UT WOS:A1997BJ16G00014 ER PT J AU Williams, HA Lowe, MK AF Williams, HA Lowe, MK TI Growth rates of four Hawaiian deep slope fishes: A comparison of methods for estimating age and growth from otolith microincrement widths SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID PRISTIPOMOIDES-FILAMENTOSUS; INCREMENTS; SNAPPER; LAYERS AB Two methods were used to estimate the age and growth of four Hawaiian deep slope fishes. Otolith daily increment width estimates from radial sections of sagittal otoliths were integrated over the otolith radius to approximate age by (i) dividing interval length (micrometres) by mean increment width (micrometres per day) and summing this quotient for consecutive 500-mu m radial intervals (S. Ralston and H.A. Williams. 1989. Fish. Bull. 87: 1-16) and (ii) fitting increment width (y) versus otolith radius (x) to a Gompertz rate curve and calculating the inverse integral of this curve (M.K. Smith and E. Kostlan. 1991. Fish. Bull. 89: 461-472). The methods also differ in the way the age-length key is generated. Ralston and Williams' method uses integrated age versus a regression-based estimate of fish length at 500-mu m otolith radial intervals; Smith and Kostlan's method uses estimated age versus actual fish length. Neither method of integration produced significantly different age estimates; however, the use of regression-based fish length estimates instead of sampled fish lengths resulted in significant differences between estimated growth curves. The minimum number of daily increment width estimates required as a function of otolith radius was calculated, on the basis of observed microincrement width variation. C1 DEPT LAND & NAT RESOURCES,DIV AQUAT RESOURCES,HONOLULU,HI 96813. RP Williams, HA (reprint author), NOAA,NATL MARINE FISHERIES SERV,SW FISHERIES CTR,HONOLULU LAB,2570 DOLE ST,HONOLULU,HI 96822, USA. NR 40 TC 10 Z9 11 U1 0 U2 5 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD JAN PY 1997 VL 54 IS 1 BP 126 EP 136 DI 10.1139/cjfas-54-1-126 PG 11 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA XB786 UT WOS:A1997XB78600014 ER PT J AU Bhatia, AK Drachman, RJ AF Bhatia, AK Drachman, RJ TI Properties of two-electron systems in an electric field SO CANADIAN JOURNAL OF PHYSICS LA English DT Article ID RYDBERG LEVELS; POLARIZABILITIES; LITHIUM; HELIUM; ION AB We have extended our previous work on the generalized polarizabilities of two-electron atoms and ions to include higher order processes and ions of atomic number Z = 2 to 6 and 10. The pseudostate summation method is used again, and the correct finite value of the nuclear mass, M, for a variety of isotopes is included in the Hamiltonian. The results are tabulated, and approximate interpolation formulas in Z and K = 2m(e)/(M + m(e)) are given. C1 NASA,GODDARD SPACE FLIGHT CTR,ASTRON & SOLAR PHYS LAB,GREENBELT,MD 20771. NR 10 TC 23 Z9 23 U1 0 U2 7 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD JAN PY 1997 VL 75 IS 1 BP 11 EP 18 DI 10.1139/cjp-75-1-11 PG 8 WC Physics, Multidisciplinary SC Physics GA XC924 UT WOS:A1997XC92400003 ER PT J AU Kowbell, W Withers, JC Demeree, F Ransone, PO AF Kowbell, W Withers, JC Demeree, F Ransone, PO TI Low cost C/C composites for cylinder liners SO CARBON LA English DT Letter DE carbon/carbon composites; impregnation; pyrolysis C1 NASA,LARC,HAMPTON,VA 23681. RP Kowbell, W (reprint author), MER CORP,TUCSON,AZ 85706, USA. NR 3 TC 1 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0008-6223 J9 CARBON JI Carbon PY 1997 VL 35 IS 8 BP 1201 EP 1203 DI 10.1016/S0008-6223(97)84655-6 PG 3 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA XT423 UT WOS:A1997XT42300025 ER PT J AU Rampino, MR AF Rampino, MR TI The galactic theory of mass extinctions: An update SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article DE mass extinction; comet showers ID CRATER FORMATION RATE; TERRESTRIAL IMPACT CRATERS; OORT COMET CLOUD; PERIODICITY HYPOTHESIS; STATISTICAL TEST; RECORD; MATTER; BODIES; GALAXY; EARTH AB Astronomical and geological evidence is consistent with the hypothesis that mass extinctions of life on Earth are related to impacts of comets whose flux is partly modulated by the dynamics of the Milky Way Galaxy. Geologic evidence for impact (ejecta and large impact craters) has been found at times of mass extinction events, and the record of large dated craters shows a significant correlation with extinctions. Statistical analyses suggest that mass extinction events exhibit a periodic component of about 30 Myr, and periodicities of 30 +/- 0.5 Myr and 35 +/- 2 Myr have been extracted from sets of well-dated large impact craters. These results suggest periodic or quasi-periodic showers of impactors, probably Oort Cloud comets, with an approximately 30 or 36 Myr cycle. The best explanation for these proposed quasi-periodic comet showers involves the Sun's vertical oscillation through the galactic disk, which may have a similar cycle time between crossings of the galactic plane. Further refinement of the model will depend on the identification and quantification of the dark matter component in the galactic disk, and discovery and accurate dating of additional impact craters. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rampino, MR (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 45 TC 7 Z9 7 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 1997 VL 69 IS 1-2 BP 49 EP 58 DI 10.1023/A:1008365913573 PG 10 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA 124KZ UT WOS:000076182600005 ER PT J AU Yeomans, DK AF Yeomans, DK TI Comet and asteroid ephemerides for spacecraft encounters SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article; Proceedings Paper CT IAU Colloquium 165 Session on Dynamics and Astrometry - Present and Future CY JUL 01-05, 1996 CL POZNAN, POLAND SP IAU, Astronom Observatory, Poznan, Observatoire Cote d Azur, Grasse ID RADAR ASTROMETRY AB To a significant degree, the success of spacecraft missions to comets and asteroids depends upon the accuracy of the target body ephemerides. In turn, accurate ephemerides depend upon the quality of the astrometric data set used in determining the object's orbit and the accuracy with which the target body's motion can be modelled. Using error analyses studies of the target bodies for the NEAR, Muses-C, Clementine 2, Stardust, and Rosetta missions, conclusions are drawn as to how to minimize target body position uncertainties at the times of encounter. In general, these uncertainties will be minimised when the object has a good number of optical observations spread over several orbital periods. If a target body lacks a lengthy data interval, its ephemeris uncertainties can be dramatically reduced with the use of radar Doppler and delay data taken when the body is relatively close to the Earth. The combination of radar and optical angle data taken at close Earth distances just before a spacecraft encounter can result in surprisingly small target body ephemeris uncertainties. RP Yeomans, DK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 12 TC 0 Z9 0 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 1997 VL 66 IS 1 BP 1 EP 12 DI 10.1007/BF00048818 PG 12 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA XH640 UT WOS:A1997XH64000002 ER PT J AU Lieske, JH AF Lieske, JH TI Galilean satellites and the Galileo space mission SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article; Proceedings Paper CT IAU Colloquium 165 Session on Dynamics and Astrometry - Present and Future CY JUL 01-05, 1996 CL POZNAN, POLAND SP IAU, Astronom Observatory, Poznan, Observatoire Cote d Azur, Grasse AB The Galileo spacecraft arrived at Jupiter in December 1995 to start its two-year mission of exploring the Jovian system. The spacecraft will complete eleven orbits around Jupiter and have ten more close encounters with the outer three Galilean satellites, after the initial close approach to Io on December 7, 1995. Since the Io encounter occurred closer to Io than originally designed, the spacecraft energy change was greater than nominally planned and resulted in an initial spacecraft orbital period about 7 days less than that designed in the nominal tour. A 100-km change in the Io-encounter distance results in an 8-day change in initial period of the spacecraft. Hence the first Granymede encounter was moved forward one week, and the aim points for the first two Ganymede encounters were altered, but all other encounters would occur on their nominal dates and at the nominal altitudes. This was accomplished without expending spacecraft fuel and resulted in the first Ganymede flyby occurring on June 27, 1996 rather than the nominally scheduled July 4. Earth- and spacecraft-based data were employed in developing ephemerides in support of the Galileo space mission. An analysis of CCD astrometric observations from 1992-1994, of photographic observations from 1967-1993, of mutual event astrometric data from 1973-1991, of Jovian eclipse timing data from 1652-1983, of Doppler data from 1987-1991, and of optical navigation data from the Voyager spacecraft encounter in 1979, produced the satellite ephemerides for the Galileo space mission. RP Lieske, JH (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 31 TC 1 Z9 1 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 1997 VL 66 IS 1 BP 13 EP 20 DI 10.1007/BF00048819 PG 8 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA XH640 UT WOS:A1997XH64000003 ER PT J AU Newhall, XX Williams, JG AF Newhall, XX Williams, JG TI Estimation of the lunar physical librations SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article; Proceedings Paper CT IAU Colloquium 165 Session on Dynamics and Astrometry - Present and Future CY JUL 01-05, 1996 CL POZNAN, POLAND SP IAU, Astronom Observatory, Poznan, Observatoire Cote d Azur, Grasse ID MOON AB The recent long-term integration of JPL ephemeris DE403/LE403 yielded lunar physical librations covering 6000 years. A Fourier analysis of a 718-year subset of this span produced estimates of the component frequencies of the forced and free librations. A subsequent iterative least-squares estimation procedure provided precise values for phases and for time-varying amplitudes and frequencies. Two free libration modes were found; presence of a third is possible but close to the noise. RP Newhall, XX (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 8 TC 34 Z9 37 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 1997 VL 66 IS 1 BP 21 EP 30 DI 10.1007/BF00048820 PG 10 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA XH640 UT WOS:A1997XH64000004 ER PT J AU Ostro, SJ AF Ostro, SJ TI Radar contributions to asteroid astrometry and dynamics SO CELESTIAL MECHANICS & DYNAMICAL ASTRONOMY LA English DT Article; Proceedings Paper CT IAU Colloquium 165 Session on Dynamics and Astrometry - Present and Future CY JUL 01-05, 1996 CL POZNAN, POLAND SP IAU, Astronom Observatory, Poznan, Observatoire Cote d Azur, Grasse ID IMAGES; TOUTATIS; SHAPE RP Ostro, SJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0923-2958 J9 CELEST MECH DYN ASTR JI Celest. Mech. Dyn. Astron. PY 1997 VL 66 IS 1 BP 87 EP 96 DI 10.1007/BF00048827 PG 10 WC Astronomy & Astrophysics; Mathematics, Interdisciplinary Applications SC Astronomy & Astrophysics; Mathematics GA XH640 UT WOS:A1997XH64000011 ER PT J AU Bhatt, RT AF Bhatt, RT TI Heat treatment effects on the tensile properties and microstructure of a SiC/RBSN composite in nitrogen SO CERAMICS INTERNATIONAL LA English DT Article ID SIC FIBER AB The room-temperature tensile properties and constituent microstructures of a unidirectionally reinforced SiC/RBSN composite have been investigated after heat treatments at 1400, 1600, or 1800 degrees C in nitrogen for up to 100 h. The composite consisted of similar to 24 vol% of aligned 140 mu m diameter, continuous length, chemically vapour deposited SiC fibres in a similar to 40% porous silicon nitride matrix. The composites heat treated at 1400 degrees C for up to 100 h showed elastic modulus, first matrix cracking strength and ultimate tensile strength values similar to those of the as-fabricated composites, but those heat treated for 1 h beyond this temperature displayed losses in all three properties. Recrystallization of the SiC fibres, loss of carbon from the carbon-rich interface coating on the fibres, and dissociation of the RBSN matrix are the reasons for the loss of mechanical properties. Published by Elsevier Science Limited and Techna S.r.l. RP Bhatt, RT (reprint author), NASA,LEWIS RES CTR,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0272-8842 J9 CERAM INT JI Ceram. Int. PY 1997 VL 23 IS 2 BP 109 EP 113 DI 10.1016/S0272-8842(96)00004-1 PG 5 WC Materials Science, Ceramics SC Materials Science GA WE968 UT WOS:A1997WE96800003 ER PT J AU DiCarlo, JA AF DiCarlo, JA TI Property goals and test methods for high temperature ceramic fibre reinforcement SO CERAMICS INTERNATIONAL LA English DT Article ID FIBERS; COMPOSITES; METAL AB As reinforcement of high temperature composites, ceramic fibres should display high creep strength and rupture strength under potential composite service conditions. Minimum goal values for these properties are developed based on reliable and successful composite application. Conventional and improved test methods for evaluating individual fibres against these goals are discussed and illustrated with recent test results for high performance SiC fibres. Published by Elsevier Science Limited. RP DiCarlo, JA (reprint author), NASA,LEWIS RES CTR,CLEVELAND,OH 44135, USA. NR 18 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0272-8842 J9 CERAM INT JI Ceram. Int. PY 1997 VL 23 IS 4 BP 283 EP 289 DI 10.1016/S0272-8842(96)00007-7 PG 7 WC Materials Science, Ceramics SC Materials Science GA WY912 UT WOS:A1997WY91200002 ER PT S AU Keohane, J AF Keohane, J BE Redish, EF Rigden, JS TI Accessible astronomical research using the World Wide Web SO CHANGING ROLE OF PHYSICS DEPARTMENTS IN MODERN UNIVERSITIES - PROCEEDINGS OF INTERNATIONAL CONFERENCE ON UNDERGRADUATE PHYSICS EDUCATION, PTS 1 AND 2 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Undergraduate Physics Education - The Changing Role of Physics Departments in Modern Universities (ICUPE) CY JUL 31-AUG 03, 1996 CL UNIV MARYLAND, COLL PK CMAPUS, COLLEGE PK, MD SP US Natl Sci Fdn, Int Union Pure & Appl Phys, Univ Maryland, Phys Dept HO UNIV MARYLAND, COLL PK CMAPUS RP Keohane, J (reprint author), NASA,GODDARD SPACE FLIGHT CTR,CODE 662,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AIP PRESS PI WOODBURY PA AMERICAN INSTITUTE OF PHYSICS 500 SUNNYSIDE BOULEVARD, WOODBURY, NY 11797-2999 SN 0094-243X BN 1-56396-698-0 J9 AIP CONF PROC PY 1997 IS 399 BP 809 EP 810 PG 2 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA BJ93N UT WOS:A1997BJ93N00085 ER PT J AU Elishakoff, I Li, YW Starnes, JH AF Elishakoff, I Li, YW Starnes, JH TI Passive control of buckling deformation via Anderson localization phenomenon SO CHAOS SOLITONS & FRACTALS LA English DT Article ID MODE LOCALIZATION AB Buckling problems of two types of multi-span elastic plates with transverse stiffeners are considered using a method based on the finite difference calculus. The discreteness of the stiffeners is accounted for. It is found that the torsional rigidity of the stiffener plays an important role in the buckling mode pattern. When the torsional rigidity is properly adjusted, the stiffener can act as an isolator of deformation for the structure at buckling so that the deflection is only limited to a small area. Copyright (C) 1997 Elsevier Science Ltd. C1 NASA, LANGLEY RES CTR, HAMPTON, VA 23664 USA. RP FLORIDA ATLANTIC UNIV, DEPT MECH ENGN, BOCA RATON, FL 33431 USA. NR 23 TC 2 Z9 3 U1 0 U2 2 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 JAN PY 1997 VL 8 IS 1 BP 59 EP 75 DI 10.1016/S0960-0779(96)00057-4 PG 17 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA WL037 UT WOS:A1997WL03700008 ER PT B AU Ross, HD AF Ross, HD GP COMBUSTION INST, E STATES SECT COMBUSTION INST, E STATES SECT COMBUSTION INST, E STATES SECT TI Burning to go: Combustion on orbit and Mars SO CHEMICAL AND PHYSICAL PROCESSES IN COMBUSTION LA English DT Proceedings Paper CT 1997 Fall Technical Meeting of the Eastern-States-Section of the Combustion-Institute on Chemical and Physical Processes in Combustion CY OCT 27-29, 1997 CL HARTFORD, CT SP Combust Inst, E States Sect C1 NASA, Lewis Res Ctr, Micrograv Combust Sci Branch, Cleveland, OH 44135 USA. RP Ross, HD (reprint author), NASA, Lewis Res Ctr, Micrograv Combust Sci Branch, MS 500-115,2100 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMBUSTION INSTITUTE EASTERN STATES SECTION PI HARTFORD PA HARTFORD, CT 00000 USA PY 1997 BP 29 EP 36 PG 8 WC Thermodynamics; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Engineering GA BK13J UT WOS:000071292500005 ER PT B AU Vander Wal, RL Ticich, TM Stephens, AB AF Vander Wal, RL Ticich, TM Stephens, AB GP COMBUSTION INST, E STATES SECT COMBUSTION INST, E STATES SECT COMBUSTION INST, E STATES SECT TI Soot primary particle size determination via LII? SO CHEMICAL AND PHYSICAL PROCESSES IN COMBUSTION LA English DT Proceedings Paper CT 1997 Fall Technical Meeting of the Eastern-States-Section of the Combustion-Institute on Chemical and Physical Processes in Combustion CY OCT 27-29, 1997 CL HARTFORD, CT SP Combust Inst, E States Sect C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA, Lewis Res Ctr, MS110-3,21 000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMBUSTION INSTITUTE EASTERN STATES SECTION PI HARTFORD PA HARTFORD, CT 00000 USA PY 1997 BP 39 EP 42 PG 4 WC Thermodynamics; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Engineering GA BK13J UT WOS:000071292500006 ER PT J AU Kim, GT Duval, WMB Glicksman, ME AF Kim, GT Duval, WMB Glicksman, ME TI Effects of asymmetric temperature profiles on thermal convection during physical vapor transport of Hg2Cl2 SO CHEMICAL ENGINEERING COMMUNICATIONS LA English DT Article DE asymmetric; temperature profile; thermal convection; vapor transport ID MERCUROUS CHLORIDE CRYSTALS; GROWTH; MODEL AB Asymmetric horizontal thermal profiles can change the flow field structure in the physical vapor transport (PVT) of Hg2Cl2. It is found that for the ratios of horizontal to vertical thermal Rayleigh numbers Ra-H/Ra greater than or equal to 1.5, the convetive flow structure changes from multicellular to unicellular for the base parametric state of Ra = 2.79 x 10(4), Pr = 0.91, Le = 1.01, Pe = 4.60, Ar = 0.2 and C-s = 1.01. The unicellular flow structure obtained by increasing Delta T-H*(Ra-H) is not likely to support the conjecture of the presence of unicellular convective mode in the laser Doppler velocimetry (LDV) experiments for PVT process of Hg2Cl2 (Kim et al., 1996). When the six parameters of Ra, PI, Le, Pe, Ar and C, are fixed, the dimensional maximum magnitude of the velocity vector \U\(max) is proportional to root Delta T-H*. C1 Hannam Univ, Dept Chem Engn, Taejon 306791, South Korea. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Rensselaer Polytech Inst, Dept Mat Engn, Troy, NY 12180 USA. RP Kim, GT (reprint author), Hannam Univ, Dept Chem Engn, Taejon 306791, South Korea. OI Glicksman, Martin/0000-0002-2675-2759 NR 27 TC 1 Z9 1 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0098-6445 J9 CHEM ENG COMMUN JI Chem. Eng. Commun. PY 1997 VL 162 BP 45 EP 61 DI 10.1080/00986449708936631 PG 17 WC Engineering, Chemical SC Engineering GA ZC085 UT WOS:000072538400004 ER PT J AU Buyevich, YA AF Buyevich, YA TI Particulate pressure in monodisperse fluidized beds SO CHEMICAL ENGINEERING SCIENCE LA English DT Article DE fluidized beds; fluctuations; particulate pressure ID VOIDAGE DISTRIBUTION; BUBBLES; INSTABILITY; MODEL; SUSPENSION; TRANSITION; CRITERION; STABILITY; MECHANICS; WAVES AB The main objective of this paper is to consider random pseudo-turbulent particle velocity fluctuations in a homogeneous fluidized bed (or in the dense phase of an inhomogeneous fluidized bed). As shown previously, these fluctuations are caused when the relative fluid flow interacts with random fluctuations of particle concentration. Bed particles are assumed to exchange their fluctuation energy and momentum through direct collisions. This being the case, and if particle concentration is sufficiently high, the particle velocity fluctuations are likely to be nearly isotropic, and so they can be characterized by a single scalar parameter. We introduce the doubled mean energy that is related to one translational degree of particle freedom in the capacity of just such a scalar parameter, and ii plays substantially the same role as temperature plays in molecular gases. However, in contrast to temperature. this energy cannot be regarded as an independent variable, but rather represents a function of mean particle concentration and of physical parameters. We then formulate the equation of stale which describes the particulate pressure that is caused by particle velocity fluctuations and is influenced by the conductivity of momentum during collisions. Thus defined, this pressure is successfully employed (1) to model the particle distribution that establishes itself to the fore of a bubble rising in a macroscopically uniform fluidized bed, and (2) to study the hydrodynamic stability of gas-fluidized beds with respect to infinitesimal one-dimensional disturbances. Copyright (C) 1996 Elsevier Science Ltd C1 NASA,AMES RES CTR,NATL RES COUNCIL,MOFFETT FIELD,CA 94035. NR 41 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0009-2509 J9 CHEM ENG SCI JI Chem. Eng. Sci. PD JAN PY 1997 VL 52 IS 1 BP 123 EP 140 DI 10.1016/S0009-2509(96)00366-1 PG 18 WC Engineering, Chemical SC Engineering GA WB409 UT WOS:A1997WB40900010 ER PT J AU Yang, K Shen, B Zhang, R Zhou, YG Chen, ZZ Chen, P Zheng, YD Huang, ZC AF Yang, K Shen, B Zhang, R Zhou, YG Chen, ZZ Chen, P Zheng, YD Huang, ZC TI Optical study of bandedge blue-shift in AlGaN/GaN double quantum wells SO CHINESE PHYSICS LETTERS LA English DT Article ID AIN BUFFER LAYER; GAN; SAPPHIRE; FILMS AB Optical properties of AlGaN/GaN double quantum wells grown by metalorganic chemical vapor deposition are investigated. The wide-angle and small angle x-ray diffraction spectra show high crystalline quality of the sample. Optical transmission and cathodoluminescence spectra exhibit that there is a. blue shift of the energy bandedge in the AlGaN/GaN double quantum wells comparing to that of bulk GaN. The experimental data are compared to theoretical calculation based on the finite square well model and a confined particle transitions are identified. The observed energy shift which differs from calculated values of ground state electron to heavy hole transition is attributed to strain in the AlGaN/CaN system. C1 NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. RP Yang, K (reprint author), NANJING UNIV,DEPT PHYS,NANJING 210093,PEOPLES R CHINA. RI Zhou, Yugang/E-3208-2013 OI Zhou, Yugang/0000-0002-5753-6602 NR 16 TC 0 Z9 0 U1 0 U2 3 PU ALLERTON PRESS INC PI NEW YORK PA 150 FIFTH AVE, NEW YORK, NY 10011 SN 0256-307X J9 CHINESE PHYS LETT JI Chin. Phys. Lett. PY 1997 VL 14 IS 9 BP 708 EP 711 PG 4 WC Physics, Multidisciplinary SC Physics GA YC660 UT WOS:A1997YC66000019 ER PT S AU Digel, SW Hunter, SD Mukherjee, R DeGeus, EJ Grenier, IA Heithausen, A Kanbach, G Thaddeus, P AF Digel, SW Hunter, SD Mukherjee, R DeGeus, EJ Grenier, IA Heithausen, A Kanbach, G Thaddeus, P BE Latter, WB Radford, SJE Jewell, PR Mangum, JG Bally, J TI Molecular clouds observed with the EGRET gamma-ray telescope SO CO: TWENTY-FIVE YEARS OF MILLIMETER-WAVE SPECTROSCOPY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 170th Symposium of the International-Astronomical-Union on CO - 25-Years of Millimeter-Wave Spectroscopy CY MAY 29-JUN 05, 1995 CL TUCSON, AZ SP Int Astron Union ID RADIAL-DISTRIBUTION; INTERSTELLAR GAS; OUTER GALAXY; OPHIUCHUS; ORION; CO; MONOCEROS; EMISSION C1 CALTECH, PASADENA, CA 91125 USA. CTR ETUD SACLAY, F-91191 GIF SUR YVETTE, FRANCE. UNIV COLOGNE, COLOGNE, GERMANY. MAX PLANCK INST EXTRATERR PHYS, GARCHING, GERMANY. HARVARD SMITHSONIAN CTR ASTROPHYS, CAMBRIDGE, MA 02138 USA. RP Digel, SW (reprint author), NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RI Hunter, Stanley/D-2942-2012 NR 13 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4283-6 J9 IAU SYMP PY 1997 IS 170 BP 22 EP 24 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH19C UT WOS:A1997BH19C00004 ER PT S AU Langer, WD AF Langer, WD BE Latter, WB Radford, SJE Jewell, PR Mangum, JG Bally, J TI Galactic carbon monoxide isotope ratios SO CO: TWENTY-FIVE YEARS OF MILLIMETER-WAVE SPECTROSCOPY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 170th Symposium of the International-Astronomical-Union on CO - 25-Years of Millimeter-Wave Spectroscopy CY MAY 29-JUN 05, 1995 CL TUCSON, AZ SP Int Astron Union ID INTERSTELLAR C-12/C-13 RATIO; MOLECULAR CLOUDS RP Langer, WD (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MS 169-506, PASADENA, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4283-6 J9 IAU SYMP PY 1997 IS 170 BP 98 EP 100 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH19C UT WOS:A1997BH19C00018 ER PT S AU Koerner, DW AF Koerner, DW BE Latter, WB Radford, SJE Jewell, PR Mangum, JG Bally, J TI Kinematics of disks around T Tauri stars SO CO: TWENTY-FIVE YEARS OF MILLIMETER-WAVE SPECTROSCOPY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 170th Symposium of the International-Astronomical-Union on CO - 25-Years of Millimeter-Wave Spectroscopy CY MAY 29-JUN 05, 1995 CL TUCSON, AZ SP Int Astron Union ID GAS RP Koerner, DW (reprint author), CALTECH, JET PROP LAB, 4800 OAK GROVE DR, MAIL STOP 169-506, PASADENA, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4283-6 J9 IAU SYMP PY 1997 IS 170 BP 162 EP 164 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH19C UT WOS:A1997BH19C00029 ER PT S AU Maloney, PR Wolfire, MG AF Maloney, PR Wolfire, MG BE Latter, WB Radford, SJE Jewell, PR Mangum, JG Bally, J TI Molecular clouds and CO emission in low-metallicity galaxies SO CO: TWENTY-FIVE YEARS OF MILLIMETER-WAVE SPECTROSCOPY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 170th Symposium of the International-Astronomical-Union on CO - 25-Years of Millimeter-Wave Spectroscopy CY MAY 29-JUN 05, 1995 CL TUCSON, AZ SP Int Astron Union C1 NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RP Maloney, PR (reprint author), UNIV COLORADO, CTR ASTROPHYS & SPACE ASTRON, CAMPUS BOX 391, BOULDER, CO 80309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4283-6 J9 IAU SYMP PY 1997 IS 170 BP 299 EP 301 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH19C UT WOS:A1997BH19C00051 ER PT S AU Latter, WB Bieging, JH AF Latter, WB Bieging, JH BE Latter, WB Radford, SJE Jewell, PR Mangum, JG Bally, J TI Unraveling mysteries in late stages of stellar evolution: The enigma of the S-type stars SO CO: TWENTY-FIVE YEARS OF MILLIMETER-WAVE SPECTROSCOPY SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 170th Symposium of the International-Astronomical-Union on CO - 25-Years of Millimeter-Wave Spectroscopy CY MAY 29-JUN 05, 1995 CL TUCSON, AZ SP Int Astron Union ID MASS-LOSS; DUST AB We report the results of an ongoing survey of S stars within 1 kpc of the Sun for emission from the J = 1 --> 0 and J = 2 --> 1 lines of CO. We derive mass loss rates from the CO emission and compare with other estimates. We find that S stars are losing copious amounts of mass at rates comparable to that of the carbon stars. There are indications that the gas-to-dust ratio is higher than for carbon stars. To aid in determining the evolutionary status of the S-type stars, we are also searching the brightest CO stars for J = 1 --> 0 HCN and J = 2 --> 1, v = 0 SiO emission. We use our results to estimate the chemical composition of the circumstellar envelopes. Comparison is made with thermodynamic equilibrium models for the formation of these and other species under photospheric conditions. C1 UNIV ARIZONA, STEWARD OBSERV, TUCSON, AZ 85721 USA. RP Latter, WB (reprint author), NASA, AMES RES CTR, MS 245-3, MOFFETT FIELD, CA 94035 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0074-1809 BN 0-7923-4283-6 J9 IAU SYMP PY 1997 IS 170 BP 367 EP 369 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BH19C UT WOS:A1997BH19C00065 ER PT B AU Burns, SH AF Burns, SH BE Hopper, DG TI International Space Station Mobile Servicing System Robotic Workstation displays and overlays SO COCKPIT DISPLAYS IV: FLAT PANEL DISPLAYS FOR DEFENSE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 4th Conference on Cockpit Displays - Flat Panel Displays for Defense Applications CY APR 23-25, 1997 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers AB The International Space Station (ISSP) currently under development is equipped with Robotic Workstations to perform and protide information on the Mobile Servicing System robotic functions in use. The workstations include conventional and special developed hardware, software displays, and control software configurations. The robotic activities are critical to the International Space Station during assembly and maintenance activities resulting in detailed crew interface requirements. Operational scenarios were used to develop the requirements of the ISSP Robotic activities resulting in the specification and configuration of the Mobile Servicing System Robotic Workstation. RP Burns, SH (reprint author), NASA,LYNDON B JOHNSON SPACE CTR,HOUSTON,TX 77058, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE - INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 BN 0-8194-2472-2 J9 P SOC PHOTO-OPT INS PY 1997 VL 3057 BP 469 EP 475 DI 10.1117/12.277027 PG 7 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BJ23L UT WOS:A1997BJ23L00050 ER PT J AU Greenberg, PS Ku, JC AF Greenberg, PS Ku, JC TI Soot volume fraction maps for normal and reduced gravity laminar acetylene jet diffusion flames SO COMBUSTION AND FLAME LA English DT Article ID RADIATIVE PROPERTIES C1 WAYNE STATE UNIV,DEPT MECH ENGN,DETROIT,MI 48202. RP Greenberg, PS (reprint author), NASA,LEWIS RES CTR,MS 110-3,21000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 10 TC 22 Z9 26 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD JAN PY 1997 VL 108 IS 1-2 BP 227 EP 230 DI 10.1016/S0010-2180(96)00205-2 PG 4 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA WA234 UT WOS:A1997WA23400017 ER PT J AU Miller, RS Bellan, J AF Miller, RS Bellan, J TI Tar yield and collection from the pyrolysis of large biomass particles SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE biomass; modeling; porous particle; pyrolysis; tar; wood ID FLASH PYROLYSIS; WOOD PYROLYSIS; HEAT-TRANSFER; SOLID FUELS; KINETICS; TEMPERATURE AB Tar yield collection from the pyrolysis of relatively large particles of biomass are investigated using the model of Miller and Bellan (1997). A variety of feedstocks are considered by varying the ratios of cellulose, hemicellulose and lignin within the biomass. Effects of secondary tar reactions, quenching, temperature, particle size and carrier gas are assessed. Secondary tar reactions occuring in both the particle's interior and the exterior boundary layer strongly reduce the potential amount of tar available for collection compared to the maximum given by kinetic predictions. The primary effect of these reactions is the existence of an optimal reactor temperature range for maximizing tar yields. This range is a function of both the quenching location and the initial particle size. For rapid quenching near the particle surface, tar collection is maximized at high temperatures for small particles, and at low temperatures for large particles. For delayed quenching low temperatures slow the secondary reactions and provide larger tar yields for all particle sizes investigated. Tar yields are also dependent on the choice of the inert carrier Bas; primarily due to changes in heat capacity. A sensitivity study is performed in order to assess the influence of the biomass apparent density, thermal conductivity, heat capacity and primary heats of reaction. RP Miller, RS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 22 TC 9 Z9 10 U1 1 U2 10 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1997 VL 127 IS 1-6 BP 97 EP 118 DI 10.1080/00102209708935689 PG 22 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA YJ669 UT WOS:A1997YJ66900006 ER PT J AU Miller, RS Bellan, J AF Miller, RS Bellan, J TI A generalized biomass pyrolysis model based on superimposed cellulose, hemicellulose and lignin kinetics SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE biomass; modeling; porous particle; pyrolysis; wood ID HEAT-TRANSFER; FLASH PYROLYSIS; WOOD PYROLYSIS; SOLID FUELS; TEMPERATURE; CONVECTION; SIMULATION; CHARCOAL; PARTICLE AB The pyrolysis of general biomass materials is modeled via a superposition of cellulose, hemicellulose and lignin kinetics. All three of the primary biomass components are modeled with multi-step kinetics involving both competetive primary pyrolysis and secondary tar decomposition reactions. Only ''typical'' (untreated) feedstocks are considered at atmospheric pyrolysis pressures. The kinetics scheme is then coupled to the porous particle model of Miller and Bellan (1996) along with appropriate properties and heats of reaction to provide a complete model for the pyrolysis of arbitrary biomass Feedstocks and sample sizes. Comparisons with past isothermal and thermogravimetry experiments for a variety of biomass materials under both kinetically controlled and diffusion limited conditions show favorable agreement with the model predictions. In addition, discussions are provided which support the use of competetive char production kinetics over single and successive reaction schems which cannot currently be reconciled with observed pyrolysis behavior. RP Miller, RS (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 41 TC 157 Z9 174 U1 0 U2 48 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1997 VL 126 IS 1-6 BP 97 EP 137 DI 10.1080/00102209708935670 PG 41 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA YE864 UT WOS:A1997YE86400005 ER PT J AU vanderWal, RL AF vanderWal, RL TI A TEM methodology for the study of soot particle structure SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE TEM; SAED; crystallite; soot; electron microscopy ID LASER-INDUCED INCANDESCENCE; LAMINAR DIFFUSION FLAMES; PREMIXED FLAMES; CARBON; AIR; GRAPHITIZATION; CARBONIZATION; DIFFRACTION; DIAGNOSTICS; ACETYLENE AB A basic discussion drawn from carbon black studies is presented as applicable to understanding soot primary particle structure. In this context, the relation between bright and dark field transmission electron microscopy (TEM) and selected area electron diffraction (SAED) is discussed. The potential for these techniques to characterize the degree of carbonization or crystallite growth of soot is discussed and then applied to soot thermophoretically sampled at different positions along the axial streamline of an ethylene gas-jet diffusion flame. Bright and dark field TEM image pairs are presented for soot thermophoretically sampled at a series of axial heights above the burner and related to the transformation process of coalesced soot precursor material into solid carbonaceous soot. The potential to quantify the degree of carbonization of the soot is examined via SAED patterns. It is found that higher resolution (via HRTEM or in the SAED patterns) is needed to extend these techniques into a quantifiable diagnostic. RP vanderWal, RL (reprint author), NYMA INC,NASA,LEWIS RES CTR,MS 110-3,22000 BROOKPK RD,CLEVELAND,OH 44135, USA. NR 74 TC 44 Z9 44 U1 1 U2 12 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1997 VL 126 IS 1-6 BP 333 EP & PG 28 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA YE864 UT WOS:A1997YE86400015 ER PT J AU Mikami, M Habara, O Kono, M Sato, J Dietrich, DL Williams, FA AF Mikami, M Habara, O Kono, M Sato, J Dietrich, DL Williams, FA TI Pressure effects in droplet combustion of miscible binary fuels SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE droplet combustion; binary fuel; high pressure; gas dissolution; critical mixing condition AB The objective of this research is to improve understanding of the combustion of binary fuel mixtures in the vicinity of the critical point. Fiber-supported droplets of mixtures of n-heptane and n-hexadecane, initially 1 mm in diameter, were burned in room-temperature air at pressures from 1 MPa to 6 MPa under free-fall microgravity conditions. For most mixtures the total burning time was observed to achieve a minimum value at pressures well above the critical pressure of either of the pure fuels. This behavior is explained in terms of critical mixing conditions of a ternary system consisting of the two fuels and nitrogen. The importance of inert-gas dissolution in the liquid fuel near the critical point is thereby re-emphasized, and nonmonotonic dependence of dissolution on initial Fuel composition is demonstrated. The results provide information that can be used to estimate high-pressure burning rates of fuel mixtures. C1 UNIV TOKYO,DEPT AERONAUT & ASTRONAUT,BUNKYO KU,TOKYO 113,JAPAN. ISHIKAWAJIMA HARIMA HEAVY IND CO LTD,RES INST,KOTO KU,TOKYO 135,JAPAN. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. UNIV CALIF SAN DIEGO,DEPT APPL MECH & ENGN SCI,CTR ENERGY & COMBUST RES,LA JOLLA,CA 92093. RP Mikami, M (reprint author), YAMAGUCHI UNIV,DEPT MECH ENGN,UBE,YAMAGUCHI 755,JAPAN. NR 17 TC 5 Z9 7 U1 0 U2 2 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING, BERKS, ENGLAND RG1 8JL SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 1997 VL 124 IS 1-6 BP 295 EP 309 DI 10.1080/00102209708935649 PG 15 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA XZ069 UT WOS:A1997XZ06900012 ER PT B AU Marner, WJ AF Marner, WJ BE Shah, RK TI Gas-side fouling in compact heat exchangers SO COMPACT HEAT EXCHANGERS FOR THE PROCESS INDUSTRIES LA English DT Proceedings Paper CT International Conference on Compact Heat Exchangers for the Process Industries CY JUN 22-27, 1997 CL SNOWBIRD, UT AB This paper presents an overview of gas-side fouling in compact heat exchangers including finned tube banks. Major topics include: (a) Phenomenological aspects of gas-side fouling, (b) Designing for gas-side fouling service, (c) Gas-side fouling studies, (d) Gas-side prevention, mitigation, and accommodation techniques, and (e) Gas-side fouling measuring devices. These topics are discussed and references from the literature are cited where appropriate. In many cases the impact of gas-side fouling is more pronounced on pressure drop than on heat transfer. Gas-side fouling is an extremely complex, multifaceted phenomenon and substantial work continues in an attempt to better understand and effectively deal with this problem. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marner, WJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 74 TC 0 Z9 0 U1 0 U2 1 PU BEGELL HOUSE, INC PI NEW YORK PA 145 MADISON AVE, NEW YORK, NY 10016 USA BN 1-56700-090-8 PY 1997 BP 161 EP 177 PG 17 WC Engineering, Chemical; Engineering, Electrical & Electronic; Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BM99M UT WOS:000080376900013 ER PT S AU Sprague, AL Nash, DB Witteborn, FC Cruikshank, DP AF Sprague, AL Nash, DB Witteborn, FC Cruikshank, DP BE Ip, WH TI Mercury's feldspar connection mid-IR measurements suggest plagioclase SO COMPARATIVE STUDIES OF THE MOON AND MERCURY SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT B0 1 Symposium of COSPAR Scientific Commission B on Comparative Studies of the Moon and Mercury, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Int Astron Union ID REFLECTANCE SPECTRA AB Mid-infrared (7.5 - 13.5 mu m) spectra of Mercury at two equatorial longitudes obtained at the Infrared Telescope Facility (IRTF) at Mauna Kea Hawaii show spectral features indicative of plagioclase feldspar ((Ca,Na)(Al,Si)AlSi2O8)). Spectra resembling that of powdered labradorite (plagioclase: Ab(50)An(50) - Ab(30)An(70)) were obtained near similar to 120 degrees mercurian longitude. Spectra from a second region near similar to 30 degrees longitude resemble laboratory spectra from a lunar breccia made up of primarily plagioclase (probably anorthite, CaAl2Si2O8) and pyroxene fragments. Abundant feldspars of varying compositions on Mercury's surface indicate that the surface is heterogeneous and that the planet is highly differentiated. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 SAN JUAN INST, SAN JUAN CAPISTRANO, CA 92674 USA. NASA, AMES RES CTR, MT VIEW, CA 94035 USA. RP Sprague, AL (reprint author), UNIV ARIZONA, LUNAR & PLANETARY LAB, TUCSON, AZ 85721 USA. NR 9 TC 45 Z9 45 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043287-5 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 10 BP 1507 EP 1510 DI 10.1016/S0273-1177(97)00363-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BJ16F UT WOS:A1997BJ16F00004 ER PT S AU Clark, PE AF Clark, PE BE Ip, WH TI X-ray spectrometry for remote exploration of mercury and the moon SO COMPARATIVE STUDIES OF THE MOON AND MERCURY SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT B0 1 Symposium of COSPAR Scientific Commission B on Comparative Studies of the Moon and Mercury, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Int Astron Union AB Any future mission to Mercury or the Moon should include an X-ray spectrometer in order to address fundamental questions of planetary origin. In the case of Mercury, where no direct geochemical measurements exist, such measurements are crucial in the understanding of the origin of Mercury and the early solar system. For the Moon, where actual surface samples are available, more complete geochemical mapping is crucial in the assessment of the potential for future development of resources and permanent bases. (C) 1997 COSPAR. Published by Elsevier Science Ltd. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. RP Clark, PE (reprint author), CATHOLIC UNIV AMER, WASHINGTON, DC 20064 USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043287-5 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 10 BP 1539 EP 1549 DI 10.1016/S0273-1177(97)00367-0 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BJ16F UT WOS:A1997BJ16F00008 ER PT S AU Potter, AE Morgan, TH AF Potter, AE Morgan, TH BE Ip, WH TI Evidence for suprathermal sodium on mercury SO COMPARATIVE STUDIES OF THE MOON AND MERCURY SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT B0 1 Symposium of COSPAR Scientific Commission B on Comparative Studies of the Moon and Mercury, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Int Astron Union ID ATMOSPHERE; MAGNETOSPHERE; EXOSPHERE; SURFACE; MOON; POTASSIUM; VAPOR AB New observations of the sodium atmosphere of Mercury show the existence of suprathermal sodium, having a temperature of several thousand degrees. This suggests that the sodium atmosphere of Mercury is largely composed of ''hot'' sodium, similar to that found for the Moon. Published by Elsevier Science Ltd on behalf of COSPAR. C1 SW RES INST, SAN ANTONIO, TX 78228 USA. RP Potter, AE (reprint author), NASA, LYNDON B JOHNSON SPACE CTR, HOUSTON, TX 77058 USA. NR 19 TC 45 Z9 45 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043287-5 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 10 BP 1571 EP 1576 DI 10.1016/S0273-1177(97)00370-0 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BJ16F UT WOS:A1997BJ16F00011 ER PT J AU Kowbel, W Bruce, C Withers, JC Ransone, PO AF Kowbel, W Bruce, C Withers, JC Ransone, PO TI Effect of carbon fabric whiskerization on mechanical properties of C-C composites SO COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING LA English DT Article DE carbon fabric; whiskerization; C-C composites AB Carbon fabric whiskerization via a direct, non-catalytic SiC whisker formation was investigated as a method to increase the shear and transverse properties of carbon-carbon (C-C) composites. The whiskers were produced via a SiO gas reaction with the carbon fiber surface. A variable level of whisker's population density was achieved by varing the whiskerization conditions. The flexure strength of phenolic resin-derived C-C composites made with the whiskerized fabric was found to be decreasing with increasing the extent of the fiber whiskerization. A 300% increase in the interlaminar strength (ILT) combined with a 250% increase in the interlaminar shear strength (ILS) was found in the case of the composites made with a low whiskerized fabric. (C) 1997 Published by Elsevier Science Limited. C1 MER Corp, Tucson, AZ USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Kowbel, W (reprint author), MER Corp, Tucson, AZ USA. NR 10 TC 26 Z9 28 U1 1 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-835X J9 COMPOS PART A-APPL S JI Compos. Pt. A-Appl. Sci. Manuf. PY 1997 VL 28 IS 12 BP 993 EP 1000 DI 10.1016/S1359-835X(97)00007-9 PG 8 WC Engineering, Manufacturing; Materials Science, Composites SC Engineering; Materials Science GA YP462 UT WOS:000071279200002 ER PT J AU Aboudi, J Pindera, MJ Arnold, SM AF Aboudi, J Pindera, MJ Arnold, SM TI Microstructural optimization of functionally graded composites subjected to a thermal gradient via the coupled higher-order theory SO COMPOSITES PART B-ENGINEERING LA English DT Article; Proceedings Paper CT FGM Symposium at the 2nd International Conference on Composites Engineerings (ICCE/2) CY AUG 21-24, 1995 CL NEW ORLEANS, LA DE microstructural optimization; higher-order theory; FGMs ID METAL-MATRIX COMPOSITE AB A recently developed higher-order theory for the response of a functionally graded composite plate subjected to a through-thickness thermal gradient is employed to optimize the composite's microstructure. The higher-order theory explicitly couples the microstructural and macrostructural effects, thereby providing a rational methodology for analyzing the response of functionally graded materials, typically analyzed using the standard uncoupled micromechanics approach, which often produces erroneous results. Herein, the higher-order theory is incorporated into an optimization algorithm to determine optimal through-thickness distributions of the reinforcement phase in a composite plate subjected to a thermal gradient that minimize the inplane moment resultant, and thus the tendency of the plate to bend about an axis. The results indicate that the manner of constraining the plate from bending due to the thermal gradient is a major factor that governs the optimal reinforcement phase distributions. (C) 1997 Elsevier Science Limited. C1 UNIV VIRGINIA, CHARLOTTESVILLE, VA 22901 USA. TEL AVIV UNIV, FAC ENGN, IL-69978 RAMAT AVIV, ISRAEL. NASA, LEWIS RES CTR, CLEVELAND, OH 44135 USA. NR 20 TC 19 Z9 21 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1359-8368 J9 COMPOS PART B-ENG JI Compos. Pt. B-Eng. PY 1997 VL 28 IS 1-2 BP 93 EP 108 DI 10.1016/S1359-8368(96)00034-0 PG 16 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA WK899 UT WOS:A1997WK89900013 ER PT J AU Pindera, MJ Aboudi, J Glaeser, AM Arnold, SM AF Pindera, MJ Aboudi, J Glaeser, AM Arnold, SM TI Foreword SO COMPOSITES PART B-ENGINEERING LA English DT Editorial Material C1 TEL AVIV UNIV,IL-69978 TEL AVIV,ISRAEL. UNIV CALIF BERKELEY,BERKELEY,CA 94720. NASA,LEWIS RES CTR,CLEVELAND,OH 44135. RP Pindera, MJ (reprint author), UNIV VIRGINIA,CHARLOTTESVILLE,VA 22903, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 1359-8368 J9 COMPOS PART B-ENG JI Compos. Pt. B-Eng. PY 1997 VL 28 IS 1-2 BP R3 EP R5 DI 10.1016/S1359-8368(97)85705-8 PG 3 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA WK899 UT WOS:A1997WK89900001 ER PT S AU Connell, JW Smith, JG Hergenrother, PM AF Connell, JW Smith, JG Hergenrother, PM BE Green, JE Beckwith, SW Strong, AB TI Adhesive and composite properties of cured imide oligomers containing pendent and terminal phenylethynyl groups SO COMPPOSITES FOR THE REAL WORLD SE INTERNATIONAL SAMPE TECHNICAL CONFERENCE SERIES LA English DT Proceedings Paper CT 29th International SAMPE Technical Conference on Composites for the Real World CY OCT 28-NOV 01, 1997 CL ORLANDO, FL SP Soc Adv Mat & Proc Engn, Composite Fabricators Assoc DE high temperature polymers; polyimides; phenylethynyl containing imides; adhesives; carbon fiber composites; oligomeric thermosetting imides; 3,5-diamino-4 '-phenylethynylbenzophenone ID POLYIMIDE OLIGOMERS; ANHYDRIDES AB As part of a program to develop high performance/high temperature structural resins for aeronautical applications, imide oligomers with calculated number average molecular weights of similar to 5000 g/mole containing pendent and terminal phenylethynyl groups were prepared, characterized, thermally cured and the cured resins evaluated as adhesives and composite matrix resins. The chemical structure of the oligomer backbone was altered to obtain a resin with an attractive combination of properties including processablity using conventional equipment, high mechanical properties and microcrack resistance. The imide oligomers containing phenylethynyl groups were fabricated into adhesive specimens using titanium adherends and composite specimens using IM-7 fiber. The laminates were fabricated in a vacuum press under 1.4 MPa for 1 hr at 350-371 degrees C. The mechanical properties measured at room and elevated temperature varied depending on the chemical structure of the oligomer backbone. Microcrack resistance was dependent upon the oligomer chemical structure. The neat resin and composite properties of these oligomers and their cured polymers will be presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 21 TC 11 Z9 11 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA SN 0892-2624 BN 0-938994-78-6 J9 INT SAMPE TECH CONF PY 1997 VL 29 BP 317 EP 331 PG 15 WC Materials Science, Multidisciplinary; Materials Science, Composites SC Materials Science GA BK24J UT WOS:000071607300030 ER PT J AU Karp, AH Geist, A Bailey, D AF Karp, AH Geist, A Bailey, D TI 1996 Gordon Bell prize winners SO COMPUTER LA English DT Article C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NASA,AMES RES CTR,NUMER AERODYNAM SIMULAT PROGRAM,MOFFETT FIELD,CA 94035. RP Karp, AH (reprint author), HEWLETT PACKARD CORP,1501 PAGE MILL RD,PALO ALTO,CA 94304, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 SN 0018-9162 J9 COMPUTER JI Computer PD JAN PY 1997 VL 30 IS 1 BP 80 EP 85 DI 10.1109/MC.1997.562930 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA WA538 UT WOS:A1997WA53800014 ER PT B AU Housner, J AF Housner, J BE Hernandez, S Brebbia, CA TI Rapid modeling, assembly and simulation in design optimization SO COMPUTER AIDED OPTIMUM DESIGN OF STRUCTURES V LA English DT Proceedings Paper CT 5th International Conference on Computer Aided Optimum Design of Structures (OPTI 97) CY SEP 08-10, 1997 CL ROME, ITALY SP Wessex Inst Technol, Southampton, UK, Univ La Corufia, Spain, Univ La Sapienza, Fac Ingegner, Rome, Italy AB A new capability for design is reviewed. This capability provides for rapid assembly of detail finite element models early in the design process where costs are most effectively impacted. This creates an engineering environment which enables comprehensive analysis and design optimization early in the design process. Graphical interactive computing makes it possible for the engineer to interact with the design while performing comprehensive design studies. This rapid assembly capability is enabled by the use of Interface Technology, to couple independently created models which can be archived and made accessible to the designer. Results are presented to demonstrate the capability. RP Housner, J (reprint author), NASA,LANGLEY RES CTR,HAMPTON,VA 23665, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPUTATIONAL MECHANICS PUBLICATIONS LTD PI SOUTHAMPTON PA ASHURST LODGE, SOUTHAMPTON, HANTS, ENGLAND S04 2AA BN 1-85312-458-3 PY 1997 BP 75 EP 84 PG 10 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA BJ79Y UT WOS:A1997BJ79Y00008 ER PT B AU Finckenor, J AF Finckenor, J BE Hernandez, S Brebbia, CA TI Genetic algorithms, with inheritance, versus gradient optimizers, and GA/gradient hybrids SO COMPUTER AIDED OPTIMUM DESIGN OF STRUCTURES V LA English DT Proceedings Paper CT 5th International Conference on Computer Aided Optimum Design of Structures (OPTI 97) CY SEP 08-10, 1997 CL ROME, ITALY SP Wessex Inst Technol, Southampton, UK, Univ La Corufia, Spain, Univ La Sapienza, Fac Ingegner, Rome, Italy AB This study compares gradient solvers, Genetic Algorithms (GA's), and two kinds of GA-gradient hybrids. Gradient optimization methods can rapidly converge to an optimum solution. However, the solution is often a local optimum, particularly if the function is noisy. The local optimum may be far from the global optimum and depends on the user input starting point. Gradient solvers are also unable to perform integer optimization. GA's are effective at finding global solutions, but require many function evaluations. The GA is an integer optimizer and can lose resolution available to gradient optimizers when operating on a continuous function. The first hybrid uses the final GA solution as a starting point for the gradient solver. The second hybrid uses each GA individual as a starting point. The representative problem is a skin-stringer construction cylinder. It is a fairly noisy design space with several discontinuities. Results compare the weight of the final solution against the function calls required. The most efficient solver is a hybrid with the GA selecting starting points and a fairly small population of 50-100 individuals. RP Finckenor, J (reprint author), NASA,GEORGE C MARSHALL SPACE FLIGHT CTR,STRUCT DEV BRANCH ED52,HUNTSVILLE,AL 35812, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU COMPUTATIONAL MECHANICS PUBLICATIONS LTD PI SOUTHAMPTON PA ASHURST LODGE, SOUTHAMPTON, HANTS, ENGLAND S04 2AA BN 1-85312-458-3 PY 1997 BP 257 EP 266 PG 10 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA BJ79Y UT WOS:A1997BJ79Y00025 ER PT S AU Landis, GA Jenkins, PP AF Landis, GA Jenkins, PP GP IEEE TI Dust on Mars: Materials Adherence Experiment results from Mars Pathfinder SO CONFERENCE RECORD OF THE TWENTY SIXTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 1997 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 26th IEEE Photovoltaic Specialists Conference CY SEP 29-OCT 03, 1997 CL ANAHEIM, CA SP IEEE Electron Devices Soc AB Mars Pathfinder is the first solar-powered probe to operate on the surface of Mars. Pathfinder consists of a lander and a small, autonomous, six-wheel solar-powered rover, "Sojourner". The Pathfinder spacecraft reflects NASA's new philosophy of exploiting new technologies to reduce mission cost The Materials Adherence Experiment on Pathfinder was designed to measure the degradation of solar arrays due to dust settling out of the atmosphere and blocking light to the solar array, lowering the array power output. The MAE measurements indicate steady dust accumulation at a rate of about 0.28% per day. This value is consistent with the performance of the solar arrays, which have decreased in power at an estimated rate of 0.29% per day. C1 NASA, Lewis Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, Lewis Res Ctr, Ohio Aerosp Inst, Mailstop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 3 Z9 4 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-3767-0 J9 IEEE PHOT SPEC CONF PY 1997 BP 865 EP 869 DI 10.1109/PVSC.1997.654224 PG 5 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics SC Energy & Fuels; Engineering; Materials Science; Optics GA BK48M UT WOS:000072313700208 ER PT S AU Gaddy, EM AF Gaddy, EM GP IEEE TI Performance of dark I-V tests to determine the condition of spacecraft solar arrays SO CONFERENCE RECORD OF THE TWENTY SIXTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 1997 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 26th IEEE Photovoltaic Specialists Conference CY SEP 29-OCT 03, 1997 CL ANAHEIM, CA SP IEEE Electron Devices Soc AB Dark I-V tests are sometimes used to determine the condition of spacecraft solar arrays. This is particularly true in cases where the array is mounted to the spacecraft such that some or all of the array cannot be illuminated. This paper shows that these tests are unable to find even significant damage to arrays and for the most part serve only as continuity checks. This is shown to be the case from both theory and experiment. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gaddy, EM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-3767-0 J9 IEEE PHOT SPEC CONF PY 1997 BP 951 EP 953 DI 10.1109/PVSC.1997.654245 PG 3 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics SC Energy & Fuels; Engineering; Materials Science; Optics GA BK48M UT WOS:000072313700229 ER PT S AU Ewell, RC Burger, DR AF Ewell, RC Burger, DR GP IEEE TI Solar array model corrections from Mars Pathfinder lander data SO CONFERENCE RECORD OF THE TWENTY SIXTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 1997 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 26th IEEE Photovoltaic Specialists Conference CY SEP 29-OCT 03, 1997 CL ANAHEIM, CA SP IEEE Electron Devices Soc AB The MESUR solar array power model initially assumed values for input variables. After landing early surface variables such as array tilt and azimuth or early environmental variables such as array temperature can be corrected. Correction of later environmental variables such as tau versus time, spectral shift, dust deposition, and UV darkening is dependent upon time, on-board science instruments, and ability to separate effects of variables. Engineering estimates had to be made for additional shadow losses and Voc sensor temperature corrections. Some variations had not been expected such as tau versus time of day, and spectral shift versus time of day. Additions needed to the model are thermal mass of lander petal and correction between Voc sensor and temperature sensor. Conclusions are: the model works well; good battery predictions are difficult; inclusion of Isc and Voc sensors was valuable; and the IMP and MAE science experiments greatly assisted the data analysis and model correction. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ewell, RC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-3767-0 J9 IEEE PHOT SPEC CONF PY 1997 BP 1019 EP 1022 DI 10.1109/PVSC.1997.654262 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Ceramics; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics SC Energy & Fuels; Engineering; Materials Science; Optics GA BK48M UT WOS:000072313700246 ER PT B AU Mjolsness, E AF Mjolsness, E BE Sun, R Alexandre, F TI Symbolic neural networks derived from stochastic grammar domain models SO CONNECTIONIST-SYMBOLIC INTEGRATION: FROM UNIFIED TO HYBRID APPROACHES LA English DT Proceedings Paper CT Workshop on Connectionist-Symbolic Integration -From Unified to Hybrid Approaches, at the 14th International Joint Conference on Artificial Intelligence (IJCAI 95) CY AUG 19-20, 1995 CL MONTREAL, CANADA RP Mjolsness, E (reprint author), CALTECH,JET PROP LAB,MACHINE LEARNING SYST GRP,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 BN 0-8058-2348-4 PY 1997 BP 279 EP 306 PG 28 WC Computer Science, Artificial Intelligence SC Computer Science GA BJ97J UT WOS:A1997BJ97J00016 ER PT B AU Richards, WL AF Richards, WL BE Aliabadi, MH Samartin, A TI Finite-element analysis of a Mach-8 flight test article using nonlinear contact elements SO CONTACT MECHANICS III LA English DT Proceedings Paper CT 3rd International Conference on Contact Mechanics CY JUL, 1997 CL MADRID, SPAIN SP Univ Politecn Madrid, Spain, Wessex Inst Technol, UK AB A flight test article, called a glove, is required for a Mach-8 boundary-layer experiment to be conducted on a flight mission of the air-launched Pegasus(R) space booster. The glove is required to provide a smooth, three-dimensional, structurally stable, aerodynamic surface and includes instrumentation to determine when and where boundary-layer transition occurs during the hypersonic flight trajectory. A restraint mechanism has been invented to attach the glove to the wing of the space booster. The restraint mechanism securely attaches the glove to the wing in directions normal to the wing/glove interface surface, but allows the glove to thermally expand and contract to alleviate stresses in directions parallel to the interface surface. A finite-element analysis has been performed using nonlinear contact elements to model the complex behavior of the sliding restraint mechanism. This paper provides an overview of the glove design and presents details of the analysis that were essential to demonstrate the flight worthiness of the wing-glove test article. Results show that all glove components are well within the allowable stress and deformation requirements to satisfy the objectives of the flight research experiment. RP Richards, WL (reprint author), NASA,DRYDEN FLIGHT RES CTR,EDWARDS AFB,CA 93523, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPUTATIONAL MECHANICS PUBLICATIONS LTD PI SOUTHAMPTON PA ASHURST LODGE, SOUTHAMPTON, HANTS, ENGLAND S04 2AA BN 1-85312-468-0 PY 1997 BP 257 EP 275 PG 19 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA BJ34G UT WOS:A1997BJ34G00026 ER PT S AU Andretta, V Jordan, SD Jones, HP Penn, MJ AF Andretta, V Jordan, SD Jones, HP Penn, MJ BE Wilson, A TI Investigating the formation of the helium spectrum with coordinated SOHO Kitt Peak Sacramento Peak observations SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE EUV; IR; radiative transfer; helium AB We present the first results of a series of observations aimed at investigating the mechanisms responsible for the formation of helium Lines in the quiescent solar atmosphere. The observations described here were taken on January, 16/17 1997, in the framework of SoHO Joint Observing Program no. 16. The SoHO instruments involved were CDS and SUMER, while ground-based support was provided by Kitt Peak (He I lambda 10830 spectra-spectroheliograms) and Sacramento Peak (Ca II K spectra-spectroheliograms). Here we concentrate our attention on some statistical properties of the helium spectrum as inferred from the SoHO/CDS and Kitt Peak observations; we also briefly discuss some constraints that such observations place in the problem of the formation mechanism. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Andretta, V (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 682, Greenbelt, MD 20771 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 163 EP 167 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200020 ER PT S AU Gibson, SE Bagenal, F Biesecker, D Guhathatkura, M Hoeksema, JT Thompson, BJ AF Gibson, SE Bagenal, F Biesecker, D Guhathatkura, M Hoeksema, JT Thompson, BJ BE Wilson, A TI Modeling a simple coronal streamer during whole sun month SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE coronal densities; coronal magnetic fields; whole sun month AB We model the simplest, most symmetric solar minimum streamer structure observed during the Whole Sun Month (WSM). We first use a Van de Hulst inversion to determine coronal electron density profiles and scale-height temperature profiles using white light coronal images from SOHO/LASCO and the HAO/MLSO coronagraphs. This method is of limited use in understanding coronal force balance, however, so we next apply the axisymmetric magnetostatic model of Gibson, Bagenal, and Low (1996). With this model we can quantify a density, temperature, and magnetic field distribution in self-consistent force balance, using both the coronal white light data and photospheric magnetic field data from the Wilcox Solar Observatory as the observational constraints on the model. This magnetostatic model, applied in a regime where solar wind velocities are below the sonic point, is currently the only model of global physical force balance (including MHD simulations) to predict a density distribution in the large scale corona (i.e. 1.2 - 2.5R(sun)) that matches white light observations to within observational error. We present the densities and temperatures attained by the Van de Hulst and magnetostatic models, and compare the magnetic field predicted by the magnetostatic model to a potential field extrapolation from the photosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gibson, SE (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 682, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 0 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 407 EP 411 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200065 ER PT S AU Guhathakurta, M Biesecker, D Gibson, S Fisher, R AF Guhathakurta, M Biesecker, D Gibson, S Fisher, R BE Wilson, A TI Polar coronal hole density and its solar wind consequences using LASCO observations SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE coronal hole; coronal densities; whole sun month; solar wind velocity AB Knowledge of the electron density in various coronal structures and their gradients in the inner and outer corona form an integral part of our understanding of the solar wind phenomenon and the coronal heating processes (Guhathakurta & Fisher 1997, Ko et al. 1997, Fisher & Guhathakurta 1995, and Habbal et al. 1995). However, until recent joint observations of Spartan 201-03 white-light coronagraph, in conjunction with Ulysses in situ north polar coronal hole plasma parameters, (Guhathakurta & Fisher 1997 and Guhathakurta, Fisher & Neugebauer 1997) and radio ranging measurements (Guhathakurta, Fisher & Woo 1997 and Guhathakurta, Woo, & Fisher 1997), electron density distribution was limited by the field of view of white-light coronagraphs (typically out to 6 R.) NOW, for the first time we have a series of white-light coronagraphs (SOHO/LASCO) whose combined field of view extends from 1.1 - 30 R. (Bruckner et al. 1995). In this paper we specifically determine the electron density of the north polar coronal hole using MkIII and LASCO C2 and C3 observations from 1.2 - 8.0 R.. The electron density in the region 1-1.2 R. has been estimated by Fludra et al. 1997. We combine these numbers with the estimate from LASCO to obtain a density profile from 1 - 8 R.. These results are then compared to the recent analysis of the Spartan 201-03 data and their implications for solar wind modeling discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Guhathakurta, M (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 682, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 421 EP 425 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200068 ER PT S AU Jordan, S Andretta, V Garcia, A Falconer, D AF Jordan, S Andretta, V Garcia, A Falconer, D BE Wilson, A TI Understanding the HE II 304 angstrom resonance line in the Sun SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE solar helium; line-formation AB Observations have been obtained with the SOHO instruments CDS and SUMER to further evaluate the hypothesis that the 304 Angstrom line is formed by collisional excitation in the quiet Sun. Previous support for this hypothesis was provided by Goddard SERTS sounding rocket experiments, which also provided evidence for small-scale flows in the quiet Sun, sufficient to resolve a discrepancy between observed and computed total line intensities. As part of a joint observing program with SERTS and several ground-based observatories, observations of photoionizing coronal radiation from CDS and of a density-sensitive transition region C III multiplet from SUMER provide sn extensive data base for continuing this investigation. rn addition, ground-based images in the +0.5 Angstrom wing of H alpha taken at the Coimbra Solar Observatory are examined for evidence of corresponding chromospheric flows. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Jordan, S (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 439 EP 443 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200071 ER PT S AU Rilee, ML Sudan, RN Pfirsch, D AF Rilee, ML Sudan, RN Pfirsch, D BE Wilson, A TI An MHD variational principle that admits reconnection SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE magnetic reconnection; magnetohydrodynamics; stability AB Ideal magnetohydrodynamics (MHD) is a popular way to model the motions of the plasma in the solar atmosphere (e.g. Priest 1994). In particular, the model's conservation of energy allows one to estimate the stability of electric current configurations with powerful and general variational techniques. In general, non-conservative systems do not admit variational techniques, so such methods have not been available for non-ideal MHD models. We have bl en working with a modification to the MHD model that allows one to use variational techniques to study equilibria that are stable in ideal MHD; but unstable when non-ideal effects are included. Detailed results are presented elsewhere (e.g. Rilee 1996). C1 NASA, Goddard Space Flight Ctr, NRC, Greenbelt, MD 20771 USA. RP Rilee, ML (reprint author), NASA, Goddard Space Flight Ctr, NRC, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 629 EP 632 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200110 ER PT S AU Ruzmaikin, A Anderson, JD Asmar, S Bird, M Cacciani, A Coles, W Feynman, J Harvey, J Harvey, K Hollweg, J Linker, J Mikic, Z Patzold, M Smith, EJ AF Ruzmaikin, A Anderson, JD Asmar, S Bird, M Cacciani, A Coles, W Feynman, J Harvey, J Harvey, K Hollweg, J Linker, J Mikic, Z Patzold, M Smith, EJ BE Wilson, A TI A spacecraft going behind the Sun will support SOHO SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE photospheric and coronal magnetic fields; coronal mass ejections AB A magneto-Doppler imager and X and Ka band linearly polarized radio signals sent to the other side of the Sun can support the extended SOHO mission in several ways: Soon after launch the spacecraft can observe weak photospheric fields simultaneously with MDI and ground instruments. Combining th-se data sets gives information on the inclination of the fields. Changes in inclination gives evidence of magnetic shear buildup, believed to cause the initiation of CMEs. When the spacecraft is off the Sun's limb (as seen from SOHO) it observes photospheric magnetic and velocity fields beneath CMEs observed by LASCO and EIT. It searches for emerging magnetic flux contributing to CME destabilization. When the spacecraft is approaching solar occultation, Faraday rotation of the radio signal passing through the corona is measured including previously unexplored regions of the inner corona, 1.1 - 4R.. The coronal magnetic field is then derived from Faraday rotation and electron density. The speed of magnetic and density inhomogenities is measured too. The magnetic field, electron density and the speed in the corona can be measured simultaneously with the LASCO, EIT and UVCS observations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 653 EP 656 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200115 ER PT S AU Thompson, BJ Newmark, JS Gurman, JB Delaboudiniere, JP Clette, F Gibson, SE AF Thompson, BJ Newmark, JS Gurman, JB Delaboudiniere, JP Clette, F Gibson, SE BE Wilson, A TI SOHO EIT Carrington maps from synoptic full-disk data SO CORONA AND SOLAR WIND NEAR MINIMUM ACTIVITY - FIFTH SOHO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th SOHO Workshop on the Corona and Solar Wind Near Minimum Activity CY JUN 17-20, 1997 CL UNIV OSLO, INST THEORET ASTROPHYS, OSLO, NORWAY SP European Space Agcy, Univ Oslo, Norges Forskningsrad, NASA, Norwegian Space Ctr, Res Council Norway, SCOSTEP HO UNIV OSLO, INST THEORET ASTROPHYS DE coronal structure AB Since May 1996, the SOHO/EIT daily synoptic observing plan has included at least one full-resolution full-disk image in each EIT bandpass: 171 Angstrom (Fe IX/X), 195 Angstrom (Fe XII), 284 Angstrom (Fe XV) and 304 Angstrom (He II/Si XI). Beginning July 1996, the nominal synoptic sequence has included several sets of half-resolution images in addition to the full-resolution images. These synoptic data sets are combined to make synoptic maps beginning at Carrington Rotation 1911. The synoptic maps at the solar meridian are generated in all four EIT wavelengths, using the same formalism as Yohkoh Soft X-ray Telescope synoptic maps. The off-limb maps at 1.05 and 1.10 solar radii are generated for the three coronal lines using the standard applied to coronagraph synoptic maps. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thompson, BJ (reprint author), NASA, Goddard Space Flight Ctr, Code 682-3 NASA Goddard, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 0 TC 4 Z9 4 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-299-0 J9 ESA SP PUBL PY 1997 VL 404 BP 779 EP 783 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK11J UT WOS:000071215200138 ER PT S AU Stebbins, A AF Stebbins, A BE Lineweaver, CH Bartlett, JG Blanchard, A Signore, M Silk, J TI The CMBR spectrum - A theoretical introduction SO COSMIC MICROWAVE BACKGROUND SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT NATO Advanced Study Institute on the Cosmological Background Radiation CY MAY 27-JUN 07, 1996 CL STRASBOURG, FRANCE SP NATO Adv Study Inst, NATO Sci Comm C1 NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. RP Stebbins, A (reprint author), NASA, Fermilab Astrophys Grp, Box 500, Batavia, IL 60510 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-4815-X J9 NATO ADV SCI I C-MAT PY 1997 VL 502 BP 241 EP 270 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL41J UT WOS:000075434900007 ER PT S AU Seo, ES Matsunaga, H Anraku, K Imori, M Makida, Y Matsumoto, H McDonald, FB Mitchell, J Moiseev, A Motoki, M Nishimura, J Nozaki, M Orito, S Ormes, JF Otoba, M Saeki, T Sanuki, T Streitmatter, RE Suzuki, J Tanaka, K Ueda, I Wang, JZ Yajima, N Yamagami, T Yamamoto, A Yoshida, T Yoshimura, K AF Seo, ES Matsunaga, H Anraku, K Imori, M Makida, Y Matsumoto, H McDonald, FB Mitchell, J Moiseev, A Motoki, M Nishimura, J Nozaki, M Orito, S Ormes, JF Otoba, M Saeki, T Sanuki, T Streitmatter, RE Suzuki, J Tanaka, K Ueda, I Wang, JZ Yajima, N Yamagami, T Yamamoto, A Yoshida, T Yoshimura, K BE Swordy, SP Westphal, AJ TI Measurement of cosmic ray H and He isotopes in a Balloon Borne Experiment with a superconducting solenoid spectrometer SO COSMIC RADIATION: SPECTRA AND COMPOSITION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1-6 and E1-7 Symposia of COSPAR Scientific Commission E on Cosmic Radiation - Spectra and Composition, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996-1997 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Union Pure & Appl Phys, Ist Nazl Fis Nucl AB The Balloon Bome Experiment with a Superconducting Solenoid Spectrometer (BESS) was flown annually in 1993, 1994, and 1995. In this report we present the energy spectra and isotopic composition of cosmic ray H and He measured from the 1993 flight. The low energy fluxes of H and He agree with the IMP-8 satellite data for a 26 day period (7/14/93 - 8/9/93) that overlapped the BESS flight. Both H-2 and He-3 were well separated from H-1 and He-4. The measured spectra were corrected for the atmospheric overburden and compared with the interstellar/heliospheric propagation calculations. (C) 1997 COSPAR. C1 UNIV TOKYO, BUNKYO KU, TOKYO 113, JAPAN. NATL LAB HIGH ENERGY PHYS, KEK, TSUKUBA, IBARAKI 305, JAPAN. KOBE UNIV, KOBE, HYOGO 657, JAPAN. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. INST SPACE & ASTRONAUT SCI, SAGAMIHARA, KANAGAWA 229, JAPAN. RP Seo, ES (reprint author), UNIV MARYLAND, INST PHYS SCI & TECHNOL, COLLEGE PK, MD 20742 USA. RI MOTOKI, Masakazu/B-4212-2009; OI Seo, Eun-Suk/0000-0001-8682-805X NR 9 TC 7 Z9 7 U1 2 U2 5 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043106-2 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 5 BP 751 EP 754 DI 10.1016/S0273-1177(96)00140-8 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH89L UT WOS:A1997BH89L00009 ER PT S AU Nishimura, J Matsunaga, H Motoki, M Moiseev, A Anraku, K Imori, M Makida, Y Matsumoto, H Mitchell, J Nozaki, M Orito, S Ormes, J Otoba, M Saeki, T Sanuki, T Streitmatter, R Suzuki, J Tanaka, K Ueda, I Yajima, N Yamagami, T Yamamoto, A Yoshida, T Yoshimura, K AF Nishimura, J Matsunaga, H Motoki, M Moiseev, A Anraku, K Imori, M Makida, Y Matsumoto, H Mitchell, J Nozaki, M Orito, S Ormes, J Otoba, M Saeki, T Sanuki, T Streitmatter, R Suzuki, J Tanaka, K Ueda, I Yajima, N Yamagami, T Yamamoto, A Yoshida, T Yoshimura, K BE Swordy, SP Westphal, AJ TI Cosmic ray antiproton spectrum measured by BESS in 1993-1995 SO COSMIC RADIATION: SPECTRA AND COMPOSITION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1-6 and E1-7 Symposia of COSPAR Scientific Commission E on Cosmic Radiation - Spectra and Composition, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996-1997 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Union Pure & Appl Phys, Ist Nazl Fis Nucl AB Balloon-borne experiment using a superconducting spectrometer were carried out successfully in northern Canada, in summer 1993 to 1995. In `93 flight, seven antiprotons were detected in the kinetic range between cen 200 and 600 MeV. The corresponding cosmic ray antiproton flux at the top of the atmosphere is fond to be 6.4(-3.5)(+5.5) x 10(-3)(m(2) sr s GeV)(-1). In '95 flight. improvement on the TOF resolution resulted to the observation of the forty antiprotons in the kinetic energy region 175 MeV to 1.3 GeV. The analysis on '95 flight is under way. (C) 1997 COSPAR. C1 NATL LAB HIGH ENERGY PHYS, KEK, TSUKUBA, IBARAKI 305, JAPAN. KOBE UNIV, KOBE, HYOGO 657, JAPAN. NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. INST SPACE & ASTRONAUT SCI, SAGAMIHARA, KANAGAWA 229, JAPAN. KANAGAWA UNIV, YOKOHAMA, KANAGAWA 221, JAPAN. RP UNIV TOKYO, BUNKYO KU, TOKYO 113, JAPAN. RI MOTOKI, Masakazu/B-4212-2009 NR 10 TC 3 Z9 3 U1 1 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043106-2 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 5 BP 771 EP 774 DI 10.1016/S0273-1177(96)00145-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH89L UT WOS:A1997BH89L00014 ER PT S AU Ptuskin, VS Jones, FC Ormes, JF Soutoul, A AF Ptuskin, VS Jones, FC Ormes, JF Soutoul, A BE Swordy, SP Westphal, AJ TI Next steps to understanding cosmic ray propagation SO COSMIC RADIATION: SPECTRA AND COMPOSITION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1-6 and E1-7 Symposia of COSPAR Scientific Commission E on Cosmic Radiation - Spectra and Composition, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996-1997 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Union Pure & Appl Phys, Ist Nazl Fis Nucl ID INTERSTELLAR-MEDIUM; GALAXY; ENERGY; NUCLEI; MODELS; MATTER AB The problems of cosmic ray transport in the interstellar medium are briefly revisited. The principal topics are the following: parameters of the basic galactic model; solution of transport equations with the use of weighted slab method; nuclear fragmentation in the cloudy interstellar medium; and radioactive isotopes in cosmic rays as a probe of the interstellar gas distribution. The focus is on the interpretation of existing data and on the theoretical support required for future experiments on galactic cosmic rays. (C) 1997 COSPAR. C1 NASA, GODDARD SPACE FLIGHT CTR, GREENBELT, MD 20771 USA. CEA SACLAY, DAPNIA, SAP, SPHN, F-91191 GIF SUR YVETTE, FRANCE. RP Ptuskin, VS (reprint author), RUSSIAN ACAD SCI, IZMIRAN, INST TERR MAGNETISM IONOSPHERE & RADIOWAVE PROPAG, TROITSK 142092, MOSCOW DISTRICT, RUSSIA. NR 33 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043106-2 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 5 BP 787 EP 794 DI 10.1016/S0273-1177(96)00148-2 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH89L UT WOS:A1997BH89L00017 ER PT S AU Reames, DV Barbier, LM vonRosenvinge, TT AF Reames, DV Barbier, LM vonRosenvinge, TT BE Swordy, SP Westphal, AJ TI WIND/EPACT observations of anomalous cosmic rays SO COSMIC RADIATION: SPECTRA AND COMPOSITION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1-6 and E1-7 Symposia of COSPAR Scientific Commission E on Cosmic Radiation - Spectra and Composition, at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996-1997 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Union Pure & Appl Phys, Ist Nazl Fis Nucl ID ENERGETIC PARTICLES AB The Energetic Particles, Acceleration, Composition and Transport (EPACT) Experiment on the WIND spacecraft, and especially its large-geometry Low Energy Matrix Telescope (LEMT), is capable of sensitive measurements of ions of the anomalous cosmic-ray (ACR) component above 2 MeV/amu. We report on the energy spectra of He, C, N, O, Ne, S, and Ar and estimate element abundances at the acceleration site. RP Reames, DV (reprint author), NASA, GODDARD SPACE FLIGHT CTR, CODE 661, GREENBELT, MD 20771 USA. NR 7 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043106-2 J9 ADV SPACE RES-SERIES PY 1997 VL 19 IS 5 BP 809 EP 812 DI 10.1016/S0273-1177(96)00151-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BH89L UT WOS:A1997BH89L00020 ER PT S AU Mlynczak, MG AF Mlynczak, MG BE Lastovicka, J Rees, D Ward, WE TI Energetics of the Mesosphere and lower Thermosphere and the SABER experiment SO COUPLING AND ENERGETICS IN THE STRATOSPHERE-MESOSPHERE-THERMOSPHERE-IONOSPHERE SYSTEM SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT Symposium C1.1 on Coupling and Energetics in the Coupled Stratosphere-Mesosphere-Thermosphere-Ionosphere System at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Union Radio Sci, Sci Comm Solar Terrestrial Phys ID LOCAL THERMODYNAMIC-EQUILIBRIUM; TERRESTRIAL MIDDLE ATMOSPHERE; INFRARED LIMB EMISSION; CARBON-DIOXIDE; ATOMIC OXYGEN; OZONE AB The energy budget of the mesosphere and lower thermosphere is governed by numerous sources and sinks of energy including radiative, chemical, and dynamical processes. The various radiative and chemical sources and sinks of energy, which occur far from local thermodynamic equilibrium (LTE), will be briefly reviewed in this paper. In addition, the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) Experiment, presently under development for the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) mission, will be introduced. SABER is an infrared emission limb sounder which will observe, at high radiometric accuracy, emissions from carbon dioxide (15 mu m), ozone (9.6 mu m), and nitric oxide (5.3 mu m) to assess temperature, radiative cooling, and ozone abundances. SABER will also observe the singlet-delta molecular oxygen emission (1.27 mu m), the Meinel bands of the hydroxyl radical (1.6 and 2.0 mu m), water vapor (6.7 mu m), and carbon dioxide emission at 4.3 mu m. From these measurements a virtually complete computation of the radiative and chemical heating and radiative cooling rates in the mesosphere and lower thermosphere can be obtained. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Mlynczak, MG (reprint author), NASA, Langley Res Ctr, Mail Stop 401B, Hampton, VA 23681 USA. RI Mlynczak, Martin/K-3396-2012 NR 15 TC 87 Z9 88 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043303-0 J9 ADV SPACE RES-SERIES PY 1997 VL 20 IS 6 BP 1177 EP 1183 DI 10.1016/S0273-1177(97)00769-2 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK15K UT WOS:000071357200015 ER PT B AU Castles, S AF Castles, S BE Ross, RG TI A case study of a successful cryogenic cooler development program SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB NASA/Goddard Space Flight Center (GSFC) has been developing long life cryogenic coolers for use in space since the 1970s. Emphasis has been steadfastly maintained on the goal of developing cryogenic coolers that can operate in an unattended manner for 5 to 10 years with very high reliability. It has been the experience of Goddard cooler personnel that many institutions still do not have an appreciation of the difficulties involved in developing such a cooler. In this paper, a successful cooler development program will be presented as a case study of the process required to develop a highly reliable, long-life cryogenic cooler. The case study covers the period 1987 through the present. It will cover the setting of the cooler requirements, the development of a program plan that lays out the resources and schedule for the overall program, the development of analytical tools used to model the most difficult technical aspects of the cooler, the hardware development and functional test cycle and the iteration of the cycle through a series of models, and the life testing. Lessons learned during the cooler development will be discussed. RP Castles, S (reprint author), NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 11 EP 16 PG 6 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00002 ER PT B AU Johnson, DL Collins, SA Heun, MK Ross, RG Kalivoda, C AF Johnson, DL Collins, SA Heun, MK Ross, RG Kalivoda, C BE Ross, RG TI Performance characterization of the TRW 3503 and 6020 pulse tube coolers SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB The Jet Propulsion Laboratory, under joint Ballistic Missile Defense Organization (BMDO)/Air Force Phillips Laboratory and NASA/EOS Atmospheric Infrared Sounder (AIRS) sponsorship, has conducted extensive characterization testing of the TRW Model 3503 and Model 6020 pulse tube cryocoolers. These coolers, built under BMDO/AFPL sponsorship, share a common design that utilizes a single-stage pulse tube integrally mounted onto 10-cc common compression space compressors, and are distinguishable by slight differences in the pulse tube designs which optimized cooler performance for operation at either 35 K or 60 K. The coolers were characterized over a range of heak rejection temperatures and cooler operating parameters (compressor stroke, piston offset, and drive frequency) to understand their effects on cooler thermal performance, cooler-generated vibration and cold block motion, and cooler-generated EMI. Pulse tube parasitic conduction as a function of cold block temperature has been studied for a non-operating cooler; the results show a strong angular dependence relative to gravity. The results of the parametric studies are presented. RP Johnson, DL (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 183 EP 193 PG 11 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00022 ER PT B AU Roach, PR Kashani, A AF Roach, PR Kashani, A BE Ross, RG TI A simple modeling program for orifice pulse tube coolers SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB We have developed a calculational model that treats all the components of an orifice pulse tube cooler. We base our analysis on 1-dimensional thermodynamic equations for the regenerator(1) and we assume that all mass flows, pressure oscillations and temperature oscillations are small and sinusoidal. The resulting mass flows and pressures are matched at the boundaries with the other components of the cooler: compressor, aftercooler, cold heat exchanger, pulse tube, hot heat exchanger, orifice and reservoir. The results of the calculation are oscillating pressures, mass flows and enthalpy flows in the main components of the cooler. By comparing with the calculations of other available models, we show that our model is very similar to REGEN 3 from NIST and DeltaE from Los Alamos National Lab for low amplitudes where there is no turbulence. Our model is much easier to use than other available models because of its simple graphical interface and the fact that no guesses are required for the operating pressures or mass flows. In addition, the model only requires a minute or so of running time, allowing many parameters to be optimized in a reasonable time. RP Roach, PR (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 327 EP 334 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00039 ER PT B AU Lee, JM Kittel, P Timmerhaus, KD Radebaugh, R AF Lee, JM Kittel, P Timmerhaus, KD Radebaugh, R BE Ross, RG TI Higher order pulse tube modeling SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB A linearized model of the pulse tube is computed to second order to study heat transfer and steady mass streaming. A two-dimensional anelastic approximation of the fluid equations is used as the basis for this analysis. Anelastic theory applies because pressure drops in the open tube of the pulse tube are negligible; it allows the equations to describe compression and expansion of the gas without mathematical formation of shocks. The calculated results are given as functions of the dimensionless numbers appropriate for oscillating compressible anelastic flows. These dimensionless numbers were previously described at the 1995 Cryogenic Engineering Conference(1). The model shows how transverse oscillating heat transfer influences enthalpy flow in the Orifice Pulse Tube. The model also quantifies the steady mass recirculation in the open tube that results from the higher order Reynolds stresses. An interesting result of the linearized approach is that steady mass streaming does not affect the steady refrigeration enthalpy flow at lower order; its effect on enthalpy flow is two orders higher. RP Lee, JM (reprint author), NASA,AMES RES CTR,MOFFETT FIELD,CA 94035, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 345 EP 346 PG 2 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00041 ER PT B AU Heun, MK Collins, SA Johnson, DL Ross, RG AF Heun, MK Collins, SA Johnson, DL Ross, RG BE Ross, RG TI Investigation of gas effects on cryocooler resonance characteristics SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB Cryocooler thermal and vibrational performance is determined, fundamentally, by the dynamic interactions between the mechanical system and the working fluid. This paper explores the effect of working-fluid characteristics on the mechanical response of the cooler. Experimental data collected from two coolers characterized under the Jet Propulsion Laboratory's extensive program of cryocooler testing and characterization show that a classical single-degree-of-freedom spring-mass-damper model does not capture the full frequency dependence of the mechanical response. The data from two modes of cooler operation (slosh and head-to-head) are used to motivate the explanation that working-fluid characteristics dominate at high frequencies, and mechanical system characteristics dominate at lower frequencies. Operating temperature is shown to be a significant factor in determining resonance behavior. Finally, the discussion provides a framework within which resonant parameters and cooler characteristics can extracted from the experimental data. RP Heun, MK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 421 EP 430 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00049 ER PT B AU Bard, S Karlmann, P Rodriguez, J Wu, J Wade, L Cowgill, P Russ, KM AF Bard, S Karlmann, P Rodriguez, J Wu, J Wade, L Cowgill, P Russ, KM BE Ross, RG TI Flight demonstration of a 10 K sorption cryocooler SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB The Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment (BETSCE), flown on STS-77 in May 1996, was the first-ever space flight of chemisorption cryocooler technology. BETSCE measured and validated critical microgravity performance characteristics of a hydride sorption cryocooler designed to cool long-wavelength infrared and submillimeter-wavelength detectors to 10 K and below. The technology flight validation data provided by BETSCE will enable early insertion of periodic and continuous-operation long-life, low-vibration, low-power consumption, sorption refrigeration technology into future earth-observation, surveillance, and astrophysics space missions. BETSCE produced solid hydrogen at 10 K in its first attempt on-orbit, cooling down from 70 K to 10 K in under 2 minutes and sustaining a 100 mW (IR)-R-2 heat load for 10 minutes, thus meeting the primary system performance objectives. In addition, a total of eight quick-cooldown liquid hydrogen cycles were completed, achieving a minimum temperature of 18.4 K and a maximum cooling duration of 32 minutes. Total cycle times ranged from 8 to 11 hours, depending on Shuttle orbiter attitude. BETSCE successfully validated sorption cooler operation in a microgravity environment. Flight data obtained for a total of eighteen compressor cycles demonstrated their ability to consistently recompress the hydrogen refrigerant fluid in a repeatable manner, and to the same high pressures as achieved in ground testing. No microgravity supercooling was observed of the n-hexadecane phase change material in the Fast Absorber Sorbent Bed, as it changed phase at its expected melting temperature of 291 K. Also, no adverse microgravity effects were observed in the cryostat cold head, as it demonstrated the ability to effectively retain liquid and solid hydrogen. RP Bard, S (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 567 EP 576 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00065 ER PT B AU Wade, LA Levy, AR Bard, S AF Wade, LA Levy, AR Bard, S BE Ross, RG TI Continuous and periodic sorption cryocoolers for 10 K and below SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB This paper presents the current status of both continuous and periodic operation sorption cryocooler development for astrophysics missions requiring refrigeration to 10 K and below. These coolers are uniquely suited for cooling detectors in planned astrophysics missions Such as the Exploration of Neighboring Planetary Systems, the Next Generation Space Telescope, and Darwin. The cooler requirements imposed by these missions include ten rear life and the ability to scale designs to provide only a few milliwatts of refrigeration while consuming only a few watts of input power. In addition, the ExNPS and Darwin missions add stringent requirements for zero-vibration and zero EMI/EMC operation. Spaceflight test results are summarized for the Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment. This periodic operation sorption cooler is ideal for applications that require only intermittent operation at 10 K with quick cooldown capability (under 2 minutes). The experiment successfully provided flight characterization of all sorption cooler design parameters which might have shown sensitivity to microgravity effects. Full ground test performance was achieved with no indications of microgravity induced changes. Ground test results from a continuous 25 K cooler planned for use in a long duration airborne balloon experiment are also presented. This 25 K cooler, which is in final integration and test, can be used as an upper stage for a continuous 10 K sorption cooler. The potential benefits of using a 10 K sorption cooler as an upper stage for a 4 K cooler are additionally described. Finally, a NASA program to develop 30 K, 10 K and 4 K vibration-free coolers for astrophysics missions, which is planned to start in FY 1997, is outlined. RP Wade, LA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 577 EP 586 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00066 ER PT B AU Wade, LA Levy, AR AF Wade, LA Levy, AR BE Ross, RG TI Preliminary test results for a 25 K sorption cryocooler designed for the UCSB long duration balloon cosmic microwave background radiation experiment SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB A continuous operation, vibration-free, long-life 25 K sorption cryocooler has been built and is now in final integration and performance testing. This cooler will be flown on the University of California at Santa Barbara Long Duration Balloon Cosmic Microwave Background Radiation experiment in Antarctica in December 1997. The cooler will refrigerate a focal plane composed of eight microwave feed horns, two working at 30 GHz and six at 42 GHz, with InP High Electron Mobility Transistor amplifiers. This will be the first hydride sorption cooler used to support an astrophysics experiment. As such, it is an important milestone in the development of vibration-free coolers for astrophysics applications. The cooler uses hydrogen as the refrigerant and LaNi4.8Sn0.2 as the hydride sorbent. The materials, components, design margins, and assembly procedures are entirely consistent with space flight qualification requirements. Several features have been incorporated into the cooler design for long term reliability and temperature stability. A high pressure tank and low pressure sorbent bed are used to stabilize the cold end temperature to better than 1 mK/sec. Small ZrNi compressors are utilized to activate the compressor element gas-gap thermal switches without valves. To greatly enhance contamination tolerance, commercially available porous metal flow restrictors are used as the Joule-Thomson plug. Passive check valves direct the refrigerant flow, simplifying cooler operation enormously. A design description and preliminary test results are presented. Also presented are the results of flow tests conducted to determine the relationship between pressure drop and hydrogen mass flow rate as a function of temperature for a range of commercially available flow restrictors. RP Wade, LA (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 587 EP 596 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00067 ER PT B AU Johnson, DL Wu, JJ AF Johnson, DL Wu, JJ BE Ross, RG TI Feasibility demonstration of a thermal switch for dual temperature IR focal plane cooling SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB A conical-shaped hydrogen gas-gap thermal switch using a metal hydride sorption bed to control the hydrogen gas supply was designed to provide the thermal isolation link between two cooling systems operating at different temperatures. Test results of the thermal switch show a nominal 1 K/W thermal resistance in the on-state conduction mode for temperatures above 100 K and for heat flows to 8 W, and a temperature dependent 600-900 WW thermal resistance in the off-state conduction mode. In particular, the off-state resistance of the switch for operation between 60 K and 140 K was 660 K/W, and with a 0.92 K/W on-state resistance at 140 K, the off-state/on-state switching ratio of 717 was achieved. The switching time to convert to the on-state or off-state mode was on the order of 5 minutes and 12 minutes, respectively. The thermal switch was integrated with a Matra Marconi Space Systems cryocooler operating at 60 K, a G-M cryocooler simulating a 140-K cryoradiator, and a simulated focal plane heat source to demonstrate the thermal isolation capability of the switch. The focal plane heat source was directly coupled to the MMS cryocooler and indirectly coupled to the G-M cryocooler through the thermal switch. Heat flows to either cooling system were quantified in the two cases of the operating and non-operating cryocooler; as well, the cooling performance of the cryocooler in the integrated configuration was determined. The test results show the successful operation of the thermal switch as the isolation link between the cryocooler and the passive cryoradiator. RP Johnson, DL (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91009, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 795 EP 805 PG 11 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00090 ER PT B AU Ross, RG Green, KE AF Ross, RG Green, KE BE Ross, RG TI AIRS cryocooler system design and development SO CRYOCOOLERS 9 LA English DT Proceedings Paper CT 9th International Cryocooler Conference CY JUN 25-27, 1996 CL WATERVILLE VALLEY, NH SP Int Cryocooler Conf Board AB JPL's Atmospheric Infrared Sounder (AIRS) instrument is based on a cryogenically cooled infrared spectrometer that uses a pair of pulse tube cryocoolers operating at 55 K to cool the HgCdTe focal plane to 58 K; the instrument also includes cryoradiators at 150 K and 190 K to cool the overall optical bench to 150 K. The cryocooler system design is a key part of the instrument development and focuses heavily on integrating the cryocoolers so as to maximize the performance of the overall instrument. The cryocooler system development activity is a highly collaborative effort involving development contracts with industry and extensive cryocooler characterization testing at JPL. In the first phases of the effort, the overall cryocooler integration approach was developed by Lockheed Martin, and TRW was selected to develop and produce the flight coolers. The selected state-of-the-art pulse tube cooler has excellent thermal performance, and has a number of attributes-particularly light weight-that greatly improve instrument integration. This paper describes the AIRS instrument overall cryogenic system design and the results achieved to dale with respect to integration of the TRW pulse tube cryocoolers into this demanding instrument. Results are presented detailing the cryogenic loads on the cooler, the overall cryocooler thermal performance margins achieved, and thermal heatsinking considerations. Mass properties of the cryocooler system, and thermal properties of the developed cold link assembly are also presented. RP Ross, RG (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 2 U2 3 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 BN 0-306-45511-0 PY 1997 BP 885 EP 894 PG 10 WC Engineering, Aerospace; Thermodynamics; Engineering, Mechanical SC Engineering; Thermodynamics GA BJ05L UT WOS:A1997BJ05L00099 ER PT B AU Kolb, EW AF Kolb, EW BE Sanchez, N Zichichi, A TI Inflation in the postmodern era SO CURRENT TOPICS IN ASTROFUNDAMENTAL PHYSICS, 5TH COURSE SE SCIENCE AND CULTURE SERIES: ASTROPHYSICS LA English DT Proceedings Paper CT 5th Course of the International School of Astrophysics (D Chalonge) on Current Topics in Astrofundamental Physics CY SEP 07-15, 1996 CL ERICE, ITALY SP Italian Minist Educ, Univ & Sci Res, Italian Minist, Sicilian Reg Govt, European Phys Soc, French Minist Foreign Affairs, French Minist Higher Educ & Res AB In this lecture I will review some recent progress in improving the accuracy of the calculation of density perturbations resulting from inflation. C1 NASA, Fermi Natl Accelerator Lab, Fermi Theoret Astrophys Grp, Batavia, IL 60510 USA. RP Kolb, EW (reprint author), NASA, Fermi Natl Accelerator Lab, Fermi Theoret Astrophys Grp, Box 500, Batavia, IL 60510 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3122-9 J9 SCI CULT SER ASTROPH PY 1997 BP 162 EP 182 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK21M UT WOS:000071549000006 ER PT S AU Gregory, FD AF Gregory, FD BE Guyenne, TD TI NASA software independent verification and validation (IV&V) - An upfront approach to mission success SO DASIA '97 - DATA SYSTEMS IN AEROSPACE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT DASIA 97 Conference on Data Systems in Aerospace CY MAY 26-29, 1997 CL SEVILLE, SPAIN SP Eurospace, CNES, Eurocontrol, European Commiss, European Space Agcy AB Because software that is mission critical is both more prevalent and more complex in today's aeronautics and space environment, software assurance is a critical aspect of NASA's safety and mission assurance program. This paper will discuss the philosophy and implementation of NASA Software Independent Verification and Validation (IV&V) as an upfront approach to mission success. To set the stage, it will describe NASA's Safety and Mission Assurance (SMA) approach, overview NASA's software assurance program and interrelationships, and discuss the origin and role of the NASA Software IV&V Facility. Software IV&V implementation methodologies, specific approaches, and accomplishments in the application of IV&V to NASA programs will be discussed. RP Gregory, FD (reprint author), NASA,WASHINGTON,DC 20546, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-319-9 J9 ESA SP PUBL PY 1997 VL 409 BP 11 EP 12 PG 2 WC Engineering, Aerospace; Computer Science, Interdisciplinary Applications SC Engineering; Computer Science GA BJ77R UT WOS:A1997BJ77R00001 ER PT S AU Tang, WC AF Tang, WC GP ASSOC COMP MACHINERY INC TI Overview of microelectromechanical systems and design processes SO DESIGN AUTOMATION CONFERENCE - PROCEEDINGS 1997 SE DESIGN AUTOMATION CONFERENCE LA English DT Proceedings Paper CT 34th Design Automation Conference CY JUN 09-13, 1997 CL ANAHEIM, CA SP ACM SIGDA, IEEE Circuits & Syst Soc, EDAC AB New design tools and automation strategies are needed to create robust, cost-effective, and manufacturable micromachined devices and systems. Same of the design automation issues include mixed-technology simulation, material property prediction In the micron-size regime, self-consistency in coupled electromechanical devices, integrated modeling environment, micro-fluid modeling, and synthesis of device geometries and process flows. Advancement in these areas will path the way to full-scale maturity of the MEMS field. RP Tang, WC (reprint author), CALTECH,JET PROP LAB,MEMS TECHNOL GRP,4800 OAK GROVE DR,PASADENA,CA 91109, USA. NR 0 TC 5 Z9 6 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 SN 0738-100X BN 0-89791-920-3 J9 DES AUT CON PY 1997 BP 670 EP 673 PG 2 WC Computer Science, Hardware & Architecture; Engineering, Manufacturing; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BH97K UT WOS:A1997BH97K00126 ER PT S AU Welch, RB AF Welch, RB BE Salvendy, G Smith, MJ Koubek, RJ TI The presence of aftereffects SO DESIGN OF COMPUTING SYSTEMS: COGNITIVE CONSIDERATIONS SE ADVANCES IN HUMAN FACTORS / ERGONOMICS LA English DT Proceedings Paper CT 7th International Conference on Human-Computer Interaction (HCI International 97) CY AUG 24-29, 1997 CL SAN FRANCISCO, CA SP Chinese Acad Sci, EEC, European Strateg Programme Res & Dev Informat Technol, ESPRIT, Human Factors & Ergon Soc, IEEE Syst Man & Cybernet Soc, Japan Ergon Soc, Japan Management Assoc AB As introduction to today's talks, the author will (1) briefly discuss our two topics-aftereffects and the sense of presence in virtual environments (VE's), (2) offer some hypotheses about their relationship, and (3) discuss the potential role of presence in performance. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-2647 BN 0-444-82183-X J9 ADV HUM FACT ERGON PY 1997 VL 21 BP 273 EP 276 PN A PG 4 WC Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Industrial; Ergonomics; Information Science & Library Science SC Computer Science; Engineering; Information Science & Library Science GA BK42Z UT WOS:000072153000068 ER PT S AU Haines, RF Doubek, S Rabin, B Harke, S AF Haines, RF Doubek, S Rabin, B Harke, S BE Smith, MJ Salvendy, G Koubek, RJ TI Information presentation and control in a modern air traffic control tower simulator SO DESIGN OF COMPUTING SYSTEMS: SOCIAL AND ERGONOMIC CONSIDERATIONS SE ADVANCES IN HUMAN FACTORS / ERGONOMICS LA English DT Proceedings Paper CT 7th International Conference on Human-Computer Interaction (HCI International 97) CY AUG 24-29, 1997 CL SAN FRANCISCO, CA SP Chinese Acad Sci, EEC, European Strateg Programme Res & Dev Informat Technol, ESPRIT, Human Factors & Ergon Soc, IEEE Syst Man & Cybernet Soc, Japan Ergon Soc, Japan Management Assoc AB The proper presentation and management of information in America's largest and busiest (Level V) air traffic control towers calls for an in-depth understanding of many different human-computer considerations: user interface design for graphical, radar, and text; manual and automated data input hardware; information/display output technology; reconfigurable workstations; workload assessment; and a comprehensive understanding of air traffic control procedures that are in use today. This paper discusses these subjects in the context of the Surface Development and Test Facility (SDTF) currently under construction at NASA's Ames Research Center, a full scale, multi-manned, air traffic control research simulator which will provide the "look and feel" of an actual airport tower cab. C1 RECOM Technol Inc, NASA, Ames Res Ctr, Div Comp Sci, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-2647 BN 0-444-82183-X J9 ADV HUM FACT ERGON PY 1997 VL 21 BP 209 EP 212 PN B PG 4 WC Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Industrial; Ergonomics; Information Science & Library Science SC Computer Science; Engineering; Information Science & Library Science GA BK43A UT WOS:000072153100051 ER PT S AU Ellis, SR Dorighi, NS Menges, BM Adelstein, BD Jacoby, RH AF Ellis, SR Dorighi, NS Menges, BM Adelstein, BD Jacoby, RH BE Smith, MJ Salvendy, G Koubek, RJ TI In search of equivalence classes in subjective scales of reality SO DESIGN OF COMPUTING SYSTEMS: SOCIAL AND ERGONOMIC CONSIDERATIONS SE ADVANCES IN HUMAN FACTORS / ERGONOMICS LA English DT Proceedings Paper CT 7th International Conference on Human-Computer Interaction (HCI International 97) CY AUG 24-29, 1997 CL SAN FRANCISCO, CA SP Chinese Acad Sci, EEC, European Strateg Programme Res & Dev Informat Technol, ESPRIT, Human Factors & Ergon Soc, IEEE Syst Man & Cybernet Soc, Japan Ergon Soc, Japan Management Assoc AB Subjects immersed in a virtual room tracked an irregularly moving cube with a cursor that was controlled by their hand position. The response latency and frame rate of the system was varied. Objective tracking accuracy was compared with subjective estimates of controllability, realism, pain and disorientation. Results show that latency had a stronger effect on performance than frame rate and that the more systematically defined subjective reports, especially an adapted Cooper-Harper scale, more closely correlated with tracking performance. C1 NASA, Ames Res Ctr, Flight Syst & Human Factors Div, Moffett Field, CA 94035 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-2647 BN 0-444-82183-X J9 ADV HUM FACT ERGON PY 1997 VL 21 BP 873 EP 876 PN B PG 4 WC Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Industrial; Ergonomics; Information Science & Library Science SC Computer Science; Engineering; Information Science & Library Science GA BK43A UT WOS:000072153100213 ER PT S AU Maida, J Aldridge, A Novak, J AF Maida, J Aldridge, A Novak, J BE Smith, MJ Salvendy, G Koubek, RJ TI Effects of lighting on human performance in training SO DESIGN OF COMPUTING SYSTEMS: SOCIAL AND ERGONOMIC CONSIDERATIONS SE ADVANCES IN HUMAN FACTORS / ERGONOMICS LA English DT Proceedings Paper CT 7th International Conference on Human-Computer Interaction (HCI International 97) CY AUG 24-29, 1997 CL SAN FRANCISCO, CA SP Chinese Acad Sci, EEC, European Strateg Programme Res & Dev Informat Technol, ESPRIT, Human Factors & Ergon Soc, IEEE Syst Man & Cybernet Soc, Japan Ergon Soc, Japan Management Assoc C1 NASA, Lyndon B Johnson Space Ctr, Flight Crew Support Div, Houston, TX 77058 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-2647 BN 0-444-82183-X J9 ADV HUM FACT ERGON PY 1997 VL 21 BP 877 EP 880 PN B PG 4 WC Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Industrial; Ergonomics; Information Science & Library Science SC Computer Science; Engineering; Information Science & Library Science GA BK43A UT WOS:000072153100214 ER PT S AU Ellis, SR Breant, F Menges, BM Jacoby, RH Adelstein, BD AF Ellis, SR Breant, F Menges, BM Jacoby, RH Adelstein, BD BE Smith, MJ Salvendy, G Koubek, RJ TI Operator interaction with virtual objects: effect of system latency SO DESIGN OF COMPUTING SYSTEMS: SOCIAL AND ERGONOMIC CONSIDERATIONS SE ADVANCES IN HUMAN FACTORS / ERGONOMICS LA English DT Proceedings Paper CT 7th International Conference on Human-Computer Interaction (HCI International 97) CY AUG 24-29, 1997 CL SAN FRANCISCO, CA SP Chinese Acad Sci, EEC, European Strateg Programme Res & Dev Informat Technol, ESPRIT, Human Factors & Ergon Soc, IEEE Syst Man & Cybernet Soc, Japan Ergon Soc, Japan Management Assoc AB A see-through head-mounted visual display was used to present computer generated, space-stabilized, nearby wire-like virtual objects to 14 subjects. The visual requirements of their experimental tasks were similar to those needed for visually-guided manual assembly of aircraft wire harnesses. An experiment examined the precision with which operators can manually move ring-shaped virtual objects over virtual paths as a function of required precision (Figure 1), path complexity, and system response latency. Tasks with placement precision better than 1.8 cm will require system latency of less than 50 msec for asymptotic performance. C1 NASA, Ames Res Ctr, Flight Syst & Human Factors Div, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-2647 BN 0-444-82183-X J9 ADV HUM FACT ERGON PY 1997 VL 21 BP 973 EP 976 PN B PG 4 WC Computer Science, Cybernetics; Computer Science, Information Systems; Engineering, Industrial; Ergonomics; Information Science & Library Science SC Computer Science; Engineering; Information Science & Library Science GA BK43A UT WOS:000072153100238 ER PT B AU Wen, L Mon, GR Ross, RG AF Wen, L Mon, GR Ross, RG BE Mahidhara, RK Frear, DR Sastry, SML Murty, KL Liaw, PK Winterbottom, WL TI Inconsistencies in the understanding of solder joint reliability physics SO DESIGN & RELIABILITY OF SOLDERS AND SOLDER INTERCONNECTIONS LA English DT Proceedings Paper CT Symposium on Design and Reliability of Solders and Solder Interconnections, at the TMS Annual Meeting CY FEB 10-13, 1997 CL ORLANDO, FL SP Minerals Met & Mat Soc, ASM MSD Flow & Fracture Comm, TMS SMD Mech Met Comm, TMS EMPMD Electr Magnet Photon Mat Comm AB An inherent reliability problem associated with surface mount applications is that solder joints, which serve as both an electrical and a mechanical connection between part and board, are subjected to thermal fatigue failure. Solder joint failure involves a complex interplay of creep and fatigue processes. Over the years, many analytical and experimental research studies have aimed to improve the state-of-the-art assessment of solder joint integrity from a physics-of-failure perspective. Although considerable progress has been made, there still exist many inconsistent and even contradictory correlations and conclusions. Before discussing some of the prominent inconsistencies found in the literature, this paper reviews the fundamental physics underlying the nature of solder failure. Many inconsistencies stem from a misunderstanding of the unique properties of near-eutectic tin-lead solder, properties such as age-and cycle-softening, grain-growth hardening, strain-rate hardening and "superplasticity". Using the complex constitutive properties of solder, fundamental mechanical and thermomechanical processes can be modeled So demonstrate some of the inconsistencies in the literature. Many analytical inconsistencies are traced to differing interpretations of the effects of temperature and cycle frequency and to results obtained from using different cycle-life prediction algorithms. Inconsistencies in testing are often found when considering mechanical versus thermal cycling, failure definitions, the determination of test acceleration factors, inspection techniques and objectives, and the treatment of failure statistics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wen, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-354-6 PY 1997 BP 219 EP 228 PG 10 WC Engineering, Mechanical; Metallurgy & Metallurgical Engineering SC Engineering; Metallurgy & Metallurgical Engineering GA BK32Q UT WOS:000071821500028 ER PT B AU Ghaffarian, R AF Ghaffarian, R BE Mahidhara, RK Frear, DR Sastry, SML Murty, KL Liaw, PK Winterbottom, WL TI The interplay of surface mount solder joint quality and reliability of low volume SMAs SO DESIGN & RELIABILITY OF SOLDERS AND SOLDER INTERCONNECTIONS LA English DT Proceedings Paper CT Symposium on Design and Reliability of Solders and Solder Interconnections, at the TMS Annual Meeting CY FEB 10-13, 1997 CL ORLANDO, FL SP Minerals Met & Mat Soc, ASM MSD Flow & Fracture Comm, TMS SMD Mech Met Comm, TMS EMPMD Electr Magnet Photon Mat Comm AB Spacecraft electronics including those used at the Jet Propulsion Laboratory (JPL), demand production of highly reliable assemblies. mt has recently completed an extensive study, funded by NASA's code Q, of the interplay between manufacturing defects and reliability of ball grid array (EGA) and surface mount electronic components. More than 400 hundred test vehicles were assembled using ceramic and plastic BGAs, LCCs, J-leads, and gull wing components. These were subjected to thermal cycle testing and solder joint defects were logged prior to testing and solder damage propagation over time was documented These fundings offer valuable information to designers and quality assurance personnel alike on package robustness as well as in better understanding the defects that can actually lead to failure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ghaffarian, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-354-6 PY 1997 BP 317 EP 328 PG 12 WC Engineering, Mechanical; Metallurgy & Metallurgical Engineering SC Engineering; Metallurgy & Metallurgical Engineering GA BK32Q UT WOS:000071821500039 ER PT B AU Bonner, K Walton, S AF Bonner, K Walton, S BE Mahidhara, RK Frear, DR Sastry, SML Murty, KL Liaw, PK Winterbottom, WL TI Qualification of ball grid array assemblies for space flight applications SO DESIGN & RELIABILITY OF SOLDERS AND SOLDER INTERCONNECTIONS LA English DT Proceedings Paper CT Symposium on Design and Reliability of Solders and Solder Interconnections, at the TMS Annual Meeting CY FEB 10-13, 1997 CL ORLANDO, FL SP Minerals Met & Mat Soc, ASM MSD Flow & Fracture Comm, TMS SMD Mech Met Comm, TMS EMPMD Electr Magnet Photon Mat Comm C1 CALTECH, Jet Prop Lab, Elect Packaging & Fabricat Sect, Pasadena, CA 91125 USA. RP Bonner, K (reprint author), CALTECH, Jet Prop Lab, Elect Packaging & Fabricat Sect, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-354-6 PY 1997 BP 329 EP 331 PG 3 WC Engineering, Mechanical; Metallurgy & Metallurgical Engineering SC Engineering; Metallurgy & Metallurgical Engineering GA BK32Q UT WOS:000071821500040 ER PT J AU Watanabe, S Miyake, S Murakawa, M Miyoshi, K AF Watanabe, S Miyake, S Murakawa, M Miyoshi, K TI Frictional durability of cubic-BN films in various environments SO DIAMOND FILMS AND TECHNOLOGY LA English DT Article; Proceedings Paper CT 11th Diamond Symposium CY DEC, 1997 CL OSAKA UNIV, OSAKA, JAPAN HO OSAKA UNIV DE cubic-BN films; frictional durability; vacuum; ambient air; water lubrication C1 Nippon Inst Technol, Miyashiro, Saitama 345, Japan. NASA, Lewis Res Ctr, Cleveland, OH USA. RP Watanabe, S (reprint author), Nippon Inst Technol, 4-1 Gakuendai, Miyashiro, Saitama 345, Japan. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MYU K K PI TOKYO PA SCIENTIFIC PUBLISHING DIV, 2-32-3 SENDAGI, BUNKYO-KU, TOKYO, 113, JAPAN SN 0917-4540 J9 DIAMOND FILM TECHNOL JI Diam. Films Technol. PY 1997 VL 7 IS 5-6 BP 317 EP 318 PG 2 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA ZG910 UT WOS:000073052300021 ER PT B AU Freund, MM Cohen, M Matsuura, M Murakami, H Kawada, M Matsumoto, T Tanaka, M Matsuura, S Noda, M AF Freund, MM Cohen, M Matsuura, M Murakami, H Kawada, M Matsumoto, T Tanaka, M Matsuura, S Noda, M BE Okuda, H Matsumoto, T Roellig, TL TI A near infrared stellar catalogue at high galactic latitudes SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB We discuss general characteristics of a stellar near InfraRed catalogue, based on recent observations of the Near Infrared Spectrometer (NIRS) on the IRTS. The catalogue of 601 stars covers a small patch at high galactic latitudes in an area of 149 degree(2) between 110< l <150 and 48< b <60. The stars have a limiting magnitude of about 10 to 7 depending on the channel and this stellar catalogue is complete to between 7 and 4 magnitude, depending on spectral channel. We furthermore present a comparison between observed star counts (LogN, Logs), and those attained by an ab intio model calculation of the stellar sources in the sky. We show that we can confidently model the stellar surface brightness of the sky, and subtract its contribution from the integrated diffuse starlight, in search for galactic and extragalactic backgrounds. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Freund, MM (reprint author), NASA, Ames Res Ctr, MS 239-4, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 67 EP 71 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600009 ER PT B AU Beichman, CA AF Beichman, CA BE Okuda, H Matsumoto, T Roellig, TL TI The 2MASS survey and the cosmic infrared background SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The combination of ground-based, near-IR sky surveys such as 2MASS and DENIS, and space-borne measurements from COBE and IRTS offer the prospect of measuring for the first time the Cosmic Infrared Background (CIRB). The near-IR surveys can reduce the stellar confusion noise inherent in large-beam measurements by permitting the subtraction of individual stars from the large-beam signals. If the required sensitivity cannot be achieved from this combination, then an experiment using a spacecraft operating with modern detector arrays to provide higher spa tial resolution and observing from 4 AU to reduce the zodiacal foreground may be required. C1 CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. RP Beichman, CA (reprint author), CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 82 EP 90 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600011 ER PT B AU Freund, MM Cohen, M Matsuura, M Murakami, H Matsumoto, T Tanaka, M Matsuura, S Noda, M AF Freund, MM Cohen, M Matsuura, M Murakami, H Matsumoto, T Tanaka, M Matsuura, S Noda, M BE Okuda, H Matsumoto, T Roellig, TL TI The NIRS point source extraction program and stellar catalogues SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB In the first part of this paper we discuss the NIRS data reduction pipeline, composed of the point source event (PSE) extractor and algorithms for associating clusters or groups of PSEs to stars and other point like objects. In the second part we describe the existing catalogue ("Mini-survey"), stellar calibrators, and future catalogue releases. Finally, we discuss the significance of the NIRS stellar databases for present and future missions and for stellar astrophysics in general. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Freund, MM (reprint author), NASA, Ames Res Ctr, MS 239-4, Moffett Field, CA 94035 USA. RI Matsuura, Shuji/B-5658-2016 OI Matsuura, Shuji/0000-0002-5698-9634 NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 114 EP 117 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600015 ER PT B AU Dwek, E AF Dwek, E BE Okuda, H Matsumoto, T Roellig, TL TI COBE observations of infrared emission from the diffuse ISM: Constraints on interstellar dust models SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The 3.5 to 500 mu m spectrum of the high-latitude diffuse ISM was recently derived from the COBE all sky survey. At short wavelengths the spectrum is consistent with emission from stochastically heated PAHs, proposed carriers of the unidentified near-IR emission band features observed in a variety of interstellar environments. At long wavelengths the spectrum is consistent with emission from a population of bare interstellar graphite and silicate grains radiating at the equilibrium dust temperatures. The COBE observations are used to assess current problems facing interstellar dust models, specifically problems of fitting the interstellar extinction curve in the face of a significant, but spectrally unknown, contribution from PAHs, and problems of meeting the cosmic abundance constraints in face of the recent "interstellar carbon crisis". C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Dwek, E (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 121 EP 130 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600016 ER PT B AU Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T AF Chan, KW Roellig, TL Onaka, T Yamamura, I Tanabe, T BE Okuda, H Matsumoto, T Roellig, TL TI 4.5 to 11.7 mu m spectrophotometeric observations of the Galactic center region by the MIRS/IRTS SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB Using the MIRS on board the IRTS we obtained the 4.5 to 11.7 mu m spectra of the diffuse interstellar medium in the Galactic center region. At all the positions we selected, the MIRS detected four features at 6.2, 7.7, 8.6, and 11.3 mu m. Weak features at 5.6 and 6.9 mu m have been detected at some positions. On average, the integrated MIRS in-band (7.7 - 11.6 mu m) flux contributes similar to 75% of the integrated IRAS 12 mu m min-band (similar to 7.5 - 15 mu m) flux at the selected positions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chan, KW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 202 EP 204 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600027 ER PT B AU Tielens, AGGM AF Tielens, AGGM BE Okuda, H Matsumoto, T Roellig, TL TI Heating and cooling of the interstellar medium SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB Interstellar gas is thought to be heated by photoelectrons ejected by small grains and PAHs. This process is briefly reviewed and the evidence for its importance is presented. Cooling of the interstellar medium is dominated by the [C II] 158 mu m line. Space based (COBE, IRTS, ISO), air borne (KAO) and balloon borne (BICE) platforms have made a wealth of dsata available on the galactic [C II] emission. Various models have been developed for the observed galactic [C II] emission, each characterized by a different ISM component: diffuse H I clouds, WIM, and PDRs on molecular cloud surfaces. These models are reviewed and contrasted with observations. It is concluded that, on a galactic scale, the WIM is very important. Many well known molecular cloud complexes are prominent in the COBE [C II] map and hence, on a local scale, H I halos around molecular clouds can be important as well. In the solar neighborhood, diffuse H I clouds dominate the [C II] emission. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Tielens, AGGM (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 255 EP 263 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600035 ER PT B AU Shafer, RA Mather, JC AF Shafer, RA Mather, JC BE Okuda, H Matsumoto, T Roellig, TL TI The far-infrared cosmic background and foregrounds: Constraints, correlations, and caveats from the analysis of CORE FIRAS data SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The COBE FIRAS (Far Infrared Absolute Spectrophotometer) mapped the far infrared sky, 100 mu m < lambda < 4100 mu m, in addition to measuring the 2.726 K Cosmic Microwave Background Radiation (CMBR). Theoretical arguments raise the possibility of significant isotropic emission, a Far Infrared Background (FIRB), from, e.g., young dusty galaxies. The detection of the FIRB is hampered by a bright, spatially variable foreground from Galactic and interplanetary dust. The minimal assumption that the foreground is everywhere positive produces a "dark sky" upper limit on the FIRB of 1.82 MJy sr(-1) at 205-405 mu m, 95% confidence. If the foreground has a single spectral shape, then a linear analysis with the constraint that the FIRB is nonnegative at all frequencies implies that the FIRB must be brighter than 0.42 MJy sr(-1) in the 205-405 mu m range. A linear analysis using the 21 cm HI as an indicator of the foreground yields a FIRB estimate that is strongly dependent on the data selection criteria. The observed data can be well represented by a model with a FIRB and a simple foreground dust distribution, or equally well by a foreground dust distribution with variable temperature, size distribution, or composition, and no FIRB. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Shafer, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 317 EP 324 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600047 ER PT B AU Helou, G Becklin, EE Stencel, RE Wilkes, BJ AF Helou, G Becklin, EE Stencel, RE Wilkes, BJ BE Okuda, H Matsumoto, T Roellig, TL TI Preliminary results from ISO: US guaranteed time projects SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB First results are reported from the four "Key Projects" carried out under the US Guaranteed Time on ISO. The Dust Debris Around Solar Mass Stars project (Becklin et al.) studies the dust disks discovered by IRAS around stars, and searches for additional examples in 150 nearby stars. It addresses the evolution of dust disks around stars with masses comparable to the Sun. The Birth and Death of Planetary Systems project (Stencel et al.) pursues the determination of the statistics of occurrence of Vega-like disk phenomena by surveying carefully selected samples. It also maps twelve bright cases of dust disk extensions, and surveys material possibly located in the Kuiper belt selected from the COBE survey. The Interstellar Medium of Normal Galaxies projects (Helou et al.) observes about 60 galaxies with infrared spectroscopy and infrared imaging, in order to derive the physical parameters of their interstellar dust, gas and radiation fields, and establish a better understanding of the galaxy-wide star formation process, its drivers and inhibitors. The Far-Infrared to X-Ray Continua of Quasars project (Wilkes et al.) surveys a representative sample of 95 quasars and active galactic nuclei at wavelengths between 5 and 200 mu m. The data are used to address the properties and nature of the infrared emission, compare the infrared spectrum to detailed models of quasars, in particular testing the "unified model" of quasars. C1 CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. RP Helou, G (reprint author), CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 393 EP 398 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600059 ER PT B AU Erickson, EF AF Erickson, EF BE Okuda, H Matsumoto, T Roellig, TL TI SOFIA: The next airborne observatory SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB SOFIA -the Stratospheric Observatory for Infrared Astronomy will be an open-port telescope with a 2.5 m effective aperture operating at altitudes of 12.5 to 13.7 km in a Boeing 747 aircraft. It will enable astronomers on board to make observations which are impossible from the ground at wavelengths between 0.3 mu m and 1.5 mm. Diffraction-limited imaging will be possible at wavelengths beyond about 10 mu m. SOFIA'S mobility will assure all-sky coverage and access to transient events from anywhere in the world. Some of the science topics to be studied are star and planet formation, origin and evolution of biogenic materials, comets and planetary atmospheres in the solar system, the interstellar media of other galaxies, and phenomena at our Galactic center. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Erickson, EF (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 415 EP 423 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600062 ER PT B AU Gautier, TN AF Gautier, TN BE Okuda, H Matsumoto, T Roellig, TL TI The NASA Space Infrared Telescope Facility SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The NASA Space Infrared Observatory Facility (SIRTF) is a cryogenically cooled space observatory being developed for use in the early years of the next century. SIRTF will carry an 85 cm primary optic cooled to 5.5K and instrumentation covering the wavelength range from 3 mu m to 180 mu m. Placement into a heliocentric orbit at a significant distance from the Earth and careful attention to thermal and cryogenic design will allow 250 liters of superfluid helium to provide a lifetime in excess of 2.5 years. The instrumentation for SIRTF will include imaging 3 mu m to 180 mu m and spectroscopy from 5 to 100 mu m. More than 75% of the observing time on SIRTF will be available to guest investigators selected from the scientific community. Within the general observer program, SIRTF is developing a "legacy" science program of major investigations to take best advantage of the unique capabilities and relatively short lifetime of the SIRTF observatory. SIRTF began definition phase funding in November of 1996. Industry partners have been selected for design and development of SIRTF and design activity began in September 1996. The development phase is expected to begin in the second quarter of 1998 leading to a launch in mid 2002. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gautier, TN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 424 EP 431 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600063 ER PT B AU Hacking, P Herter, T Stacey, G Houck, JR Shupe, DL Lonsdale, C Gautier, TN Schember, HR Werner, MW Soifer, BT Moseley, SH Graf, P AF Hacking, P Herter, T Stacey, G Houck, JR Shupe, DL Lonsdale, C Gautier, TN Schember, HR Werner, MW Soifer, BT Moseley, SH Graf, P BE Okuda, H Matsumoto, T Roellig, TL TI The Wide-Field Infrared Explorer (WIRE) Mission SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The Wide-Field Infrared Explorer (WIRE) was selected in 1994 for launch in 1998 as NASA's 5th Small Explorer mission. WIRE's primary science objective is to conduct a deep infrared survey to investigate the evolution of starburst galaxies and search for protogalaxies at high redshifts. WIRE will survey hundreds of square degrees at 12 and 25 mu m at 200-2000 times fainter flux levels than the IRAS Faint Source Catalog (0.1-1.0 mJy, depending upon wavelength and depth of coverage). We anticipate that WIRE will detect about 100,000 starburst galaxies, at typical redshifts of 0.5, and potentially hundreds of protogalaxies at much higher redshifts. The WIRE instrument consists of a 30-cm telescope in a dual-stage, solid-hydrogen cryostat, and utilizes two 128x128 format Si:As BIB detectors. NASA is currently planning an Announcement of Opportunity for Associate Investigators to utilize WIRE in collaboration with WIRE science team on topics not related to WIRE's primary objective. C1 CALTECH, Jet Prop Lab, Jamieson Sci & Engn, Pasadena, CA 91109 USA. RP Hacking, P (reprint author), CALTECH, Jet Prop Lab, Jamieson Sci & Engn, MS 100-22, Pasadena, CA 91109 USA. RI Moseley, Harvey/D-5069-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 432 EP 440 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600064 ER PT B AU Mather, JC Bely, PY Stockman, P Thronson, H AF Mather, JC Bely, PY Stockman, P Thronson, H BE Okuda, H Matsumoto, T Roellig, TL TI The Next Generation Space Telescope, NGST SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The Next Generation Space Telescope (NGST) is conceived as a radiatively cooled near IR optimized telescope of more than 4 m aperture, at the Lagrange point L2, launched on an Atlas IIAS class vehicle around 2007. A deployable telescope, adjusted to correct figure after launch, would allow an aperture of 8 m. A deployable sunshield and suitable isolation structures would permit radiative cooling to 30-70 K, enabling operation at wavelengths as long as 20 mu m or more at sensitivities limited by the zodiacal light. Planned instruments include wide field cameras and multiobject spectrometers, optimized for the study of distant galaxies and early star formation in the 1-5 mu m band. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mather, JC (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 441 EP 448 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600065 ER PT B AU Thronson, HA AF Thronson, HA BE Okuda, H Matsumoto, T Roellig, TL TI NASA's Origins Theme and the future of IR space astronomy SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI AB The Origins Theme at NASA Headquarters has, as its primary goal, the understanding of the birth and early evolution of some of the fundamental constiuents of the Universe: galaxies, stars, planets, and life. As such, it encompasses a wide range of facilities, instruments, and technologies, with a variety of capabilities, including very-high-precision interferometry and large-collecting-area optical systems, with an emphasis on observations in the infrared. This paper summarizes the current plans and missions for the Origins Program, emphasizing work at infrared wavelengths. C1 NASA Headquarters, Off Space Sci, Washington, DC 20546 USA. RP Thronson, HA (reprint author), NASA Headquarters, Off Space Sci, Code SR,300 E St SW, Washington, DC 20546 USA. RI Thronson, Harley/E-3382-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 449 EP 453 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600066 ER PT B AU Gautier, TN AF Gautier, TN BE Okuda, H Matsumoto, T Roellig, TL TI An all sky cirrus confusion noise map for WIRE SO DIFFUSE INFRARED RADIATION AND THE IRTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Diffuse Infrared Radiation and the IRTS CY NOV 11-14, 1996 CL INST SPACE & ASTRONAUT SCI, SAGAMIHARA, JAPAN SP Inoue Fdn Sci, Soc Promot Space Sci HO INST SPACE & ASTRONAUT SCI C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gautier, TN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-44-9 J9 ASTR SOC P PY 1997 VL 124 BP 482 EP 485 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK80D UT WOS:000073443600070 ER PT B AU Yeomans, DK AF Yeomans, DK BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI Comet and asteroid ephemerides for spacecraft encounters SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech AB To a significant degree, the success of spacecraft missions to comets and asteroids depends upon the accuracy of the target body ephemerides. In turn, accurate ephemerides depend upon the quality of the astrometric data set used in determining the object's orbit and the accuracy with which the target body's motion can be modelled. Using error analyses studies of the target bodies for the NEAR, Muses-C, Clementine 2, Stardust, and Rosetta missions, conclusions are drawn as to how to minimize target body position uncertainties at the times of encounter. In general, these uncertainties will be minimized when the object has a good number of optical observations spread over several orbital periods. If a target body lacks a lengthy data interval, its ephemeris uncertainties can be dramatically reduced with the use of radar Doppler and delay data taken when the body is relatively close to the Earth. The combination of radar and optical angle data taken at close Earth distances just before a spacecraft encounter can result in surprisingly small target body ephemeris uncertainties. RP Yeomans, DK (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 301 150G,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 1 EP 12 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00001 ER PT B AU Lieske, JH AF Lieske, JH BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI Galilean satellites and the Galileo space mission SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech AB The Galileo spacecraft arrived at Jupiter in December 1995 to start its two-year mission of exploring the Jovian system. The spacecraft will complete eleven orbits around Jupiter and have ten more close encounters with the outer three Galilean satellites, after the initial close approach to Io on December 7, 1995. Since the 10 encounter occurred closer to Io than originally designed, the spacecraft energy change was greater than nominally planned and resulted in an initial spacecraft orbital period about 7 days less than that designed in the nominal tour. A 100-km change in the Io-encounter distance results in an 8-day change in initial period of the spacecraft. Hence the first Ganymede encounter was moved forward one week, and the aim points for the first two Ganymede encounters were altered, but all other encounters would occur on their nominal dates and at the nominal altitudes. This was accomplished without expending spacecraft fuel and resulted in the first Ganymede flyby occurring on June 27, 1996 rather than the nominally scheduled July 4. Earth-and spacecraft-based data were employed in developing ephemerides in support of the Galileo space mission. An analysis of CCD astrometric observations from 1992-1994, of photographic observations from 1967-1993, of mutual event astrometric data from 1973-1991, of Jovian eclipse timing data from 1652-1983, of Doppler data from 1987-1991, and of optical navigation data from the Voyager spacecraft encounter in 1979, produced the satellite ephemerides for the Galileo space mission. RP Lieske, JH (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 301-150,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 13 EP 20 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00002 ER PT B AU Newhall, XX Williams, JG AF Newhall, XX Williams, JG BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI Estimation of the lunar physical librations SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech AB The recent long-term integration of JPL ephemeris DE403/LE403 yielded lunar physical librations covering 6000 years. A Fourier analysis of a 718-year subset of this span produced estimates of the component frequencies of the forced and free librations. A subsequent iterative least-squares estimation procedure provided precise values for phases and for time-varying amplitudes and frequencies. Two free libration modes were found; presence of a third is possible but close to the noise. RP Newhall, XX (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 238-332,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 21 EP 30 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00003 ER PT B AU Ostro, SJ AF Ostro, SJ BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI Radar contributions to asteroid astrometry and dynamics SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech RP Ostro, SJ (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 300 233,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 87 EP 96 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00010 ER PT B AU Acton, CH AF Acton, CH BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI NASA's spice system models the solar system SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech AB The Navigation Ancillary Information Facility (NAIF) at Caltech's Jet Propulsion Laboratory acting under the directions of NASA's Office of Space Science, has built a data system-named SPICE-to assist scientists in planning and interpreting scientific observations. SPICE provides geometric and some other ancillary information needed to recover the full value of science instrument data, including correlation of individual instrument data sets with data from other instruments on the same or other spacecraft. The primary SPICE data sets are called ''kernels.'' One of these kernel types provides ready access to ephemerides of spacecraft, planets, satellites, comets and asteroids. A second kernel type provides a set of data specifying target body size, shape and orientation. These data are currently based primarily on IAU/IAG/COSPAR models. The SPICE system includes FORTRAN subroutines needed to read the kernel files and to calculate many common observation geometry parameters. Users integrate these SPICE ''Toolkit'' subroutines into their own application programs to compute needed information. RP Acton, CH (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 301-125L,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 257 EP 262 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00034 ER PT B AU Harris, AW Wisniewski, WZ AF Harris, AW Wisniewski, WZ BE Wytrzyszczak, IM Lieske, JH Feldman, RA TI Asteroid spins: From the very fast to the very slow SO DYNAMICS AND ASTROMETRY OF NATURAL AND ARTIFICIAL CELESTIAL BODIES LA English DT Proceedings Paper CT IAU Colloquium 165 - Dynamics and Astrometry of Natural and Artificial Celestial Bodies CY JUL 01-05, 1996 CL POZNAN, POLAND SP Int Astron Union, Polish Comm Sci Res, A Mickiewicz Univ Poznan, Polish Acad Sci, Comm Astron, French Minist Foreign Affairs, French Embassy Warsaw, Observatoire Cote Azur, Polish Airlines LOT, Poznan Breweries Lech RP Harris, AW (reprint author), CALTECH,JET PROP LAB,4800 OAK GROVE DR,MAIL STOP 183-501,PASADENA,CA 91109, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4574-6 PY 1997 BP 265 EP 268 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BJ40C UT WOS:A1997BJ40C00035 ER PT J AU Hanner, MS Gehrz, RD Harker, DE Hayward, TL Lynch, DK Mason, CC Russell, RW Williams, DM Wooden, DH Woodward, CE AF Hanner, MS Gehrz, RD Harker, DE Hayward, TL Lynch, DK Mason, CC Russell, RW Williams, DM Wooden, DH Woodward, CE TI Thermal emission from the dust coma of comet Hale-Bopp and the composition of the silicate grains SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet Hale-Bopp; infrared; dust; silicates ID INTERPLANETARY DUST; PARTICLES; SPECTRA; P/HALLEY; OLIVINE; BOWELL AB The dust coma of comet Hale-Bopp was observed in the thermal infrared over a wide range in solar heating (R = 4.9-0.9 AU) and over the full wavelength range from 3 mu m to 160 mu m. Unusual early activity produced an extensive coma containing small warm refractory grains; already at 4.9 AU, the 10 mu m silicate emission feature was strong and the color temperature was 30% above the equilibrium blackbody temperature. Near perihelion the high color temperature, strong silicate feature, and high albedo indicated a smaller mean grain size than in other comets. The 8-13 mu m spectra revealed a silicate emission feature similar in shape to that seen in P/Halley and several new and long period comets. Detailed spectral structure in the feature was consistent over time and with different instruments; the main peaks occur at 9.3, 10.0 and 11.2 mu m. These peaks can be identified with olivine and pyroxene minerals, linking the comet dust to the anhydrous chondritic aggregate interplanetary dust particles. Spectra at 16-40 mu m taken with the ISO SWS displayed pronounced emission peaks due to Mg-rich crystalline olivine, consistent with the 11.2 mu m peak. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Wyoming, Dept Phys & Astron, Wyoming Infrared Observ, Laramie, WY 82071 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Aerospace Corp, Los Angeles, CA 90009 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hanner, MS (reprint author), CALTECH, Jet Prop Lab, MS 183-501, Pasadena, CA 91109 USA. OI Harker, David/0000-0001-6397-9082 NR 42 TC 35 Z9 36 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 79 IS 1-3 BP 247 EP 264 DI 10.1023/A:1006201820477 PG 18 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 284ZF UT WOS:000085362200014 ER PT J AU Hofstadter, MD Hartogh, P McMullin, JP Martin, RN Jarchow, C Peters, W AF Hofstadter, MD Hartogh, P McMullin, JP Martin, RN Jarchow, C Peters, W TI A search for variability in the HCN to H2CO ratio in comet Hale-Bopp SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet; HCN; H2CO; variability; submillimeter AB We observed submillimeter lines of H2CO and HCN in comet Hale-Bopp near perihelion. One of our goals was to search for short term variability. Our observations are suggestive, but not conclusive, of temporal and/or spatial changes in the coma's HCN/H2CO abundance ratio of similar to 25%. If due to spatial variability, the ratio on the sunward side of the coma is enhanced over other regions. If due to temporal variability, we find the bulk ratio in the coma changed in less than 16 hours. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Natl Radio Astron Observ, Green Bank, WV 24944 USA. Acad Sinica, Inst Astron & Astrophys, Taipei 115, Taiwan. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Hofstadter, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 2 Z9 2 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 53 EP 61 PG 9 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400009 ER PT J AU Weaver, HA Brooke, TY Chin, G Kim, SJ Bockelee-Morvan, D Davies, JK AF Weaver, HA Brooke, TY Chin, G Kim, SJ Bockelee-Morvan, D Davies, JK TI Infrared spectroscopy of comet Hale-Bopp SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE infrared; spectroscopy; composition; comets ID EXCITATION; HYAKUTAKE; WATER; CO AB High resolution (lambda/delta lambda similar to 20,000) spectra of comet C/1995 O1 (Hale-Bopp) in the 2-5 mu m region were obtained during UT 2-5 March 1997 using CSHELL at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. The heliocentric and geocentric distances of the comet were similar to 1.1 AU and similar to 1.5 AU, respectively. We detected emission lines of the gas-phase molecules H2O, CH4,C2H6, (CH2)-H-2, HCN, and CO and derived absolute production rates and relative abundances for all species. We also used the 2-dimensional nature of the CSHELL data to investigate the spatial distribution of the molecules and find evidence that CO was derived at least partly from an extended source in the coma. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. Kyunghee Univ, Inst Nat Sci, Yongin 449701, Kyunggido, South Korea. Observ Meudon Paris, F-92195 Meudon, France. Joint Astron Ctr, Hilo, HI 96720 USA. RP Weaver, HA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Chin, Gordon/E-1520-2012; Kim, Sang Joon/E-2383-2013; Weaver, Harold/D-9188-2016 NR 14 TC 18 Z9 18 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 71 EP 80 DI 10.1023/A:1006227530238 PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400013 ER PT J AU Leech, K Crovisier, J Bockelee-Morvan, D Brooke, TY Hanner, MS Altieri, B Keller, HU Lellouch, E Lim, T AF Leech, K Crovisier, J Bockelee-Morvan, D Brooke, TY Hanner, MS Altieri, B Keller, HU Lellouch, E Lim, T TI The infrared spectrum of comet Hale-Bopp as seen by the Infrared Space Observatory SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE C/1995 O1 Hale-Bopp; comets; infrared spectroscopy; ISO ID SUN C1 ESA, Div Astrophys, ISO Sci Operat Ctr, Villafranca, Spain. Observ Paris Meudon, F-92195 Meudon, France. CALTECH, Jet Prop Lab, Pasadena, CA USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. RP Leech, K (reprint author), ESA, Div Astrophys, ISO Sci Operat Ctr, Villafranca, Spain. NR 3 TC 6 Z9 6 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 81 EP 83 DI 10.1023/A:1006283614308 PG 3 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400014 ER PT J AU Lisse, CM Fernandez, YR A'Hearn, MF Kostiuk, T Livengood, TA Kaufl, HU Hoffmann, WF Dayal, A Ressler, ME Hanner, MS Fazio, GG Hora, JL Peschke, SB Grun, E Deutsch, LK AF Lisse, CM Fernandez, YR A'Hearn, MF Kostiuk, T Livengood, TA Kaufl, HU Hoffmann, WF Dayal, A Ressler, ME Hanner, MS Fazio, GG Hora, JL Peschke, SB Grun, E Deutsch, LK TI Infrared observations of dust emission from comet Hale-Bopp SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comets : infrared; radio; rotation; surfaces; origin ID C/1995-O1 AB We present infrared imaging and photometry of the bright, giant comet C/1995 O1 (Hale-Bopp). The comet was observed in an extended infrared and optical observing campaign in 1996-1997. The infrared morphology of the comet was observed to change from the 6 to 8 jet "porcupine" structure in 1996 to the "pinwheel" structure seen in 1997; this has implications for the position of the rotational angular momentum vector. Long term light curves taken at 11.3 mu m indicate a dust production rate that varies with heliocentric distance as similar to r(-1.4). Short term light curves taken at perihelion indicate a rotational periodicity of 11.3 hours and a projected dust outflow speed of similar to 0.4 km s(-1). The spectral energy distribution of the dust on October 31, 1996 is well modeled by a mixture of 70% silicaceous and 30% carbonaceous non-porous grains, with a small particle dominated size distribution like that seen for comet P/Halley (McDonnell et al., 1991), an overall dust production rate of 2 x 10(5) kg s(-1), a dust-to-gas ratio of similar to 5, and an albedo of 39%. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ESO, D-85748 Garching, Germany. NASA, JPL, Pasadena, CA 91104 USA. Harvard Univ, SAO, OPt & Infrared Astron Div, Cambridge, MA 02138 USA. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Boston Univ, Dept Astron, Boston, MA 02215 USA. RP Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM lisse@astro.umd.edu RI Livengood, Timothy/C-8512-2012; Kostiuk, Theodor/A-3077-2014; Lisse, Carey/B-7772-2016; OI Lisse, Carey/0000-0002-9548-1526; Fernandez, Yanga/0000-0003-1156-9721; Hora, Joseph/0000-0002-5599-4650 NR 11 TC 11 Z9 11 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-9295 EI 1573-0794 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 251 EP 257 DI 10.1023/A:1006261303055 PG 7 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400039 ER PT J AU Hayward, TL Hanner, MS AF Hayward, TL Hanner, MS TI Spectrocam-10 thermal infrared observations of the dust in comet C/1995 O1 Hale-Bopp SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comets; infrared; silicate feature ID MICRON AB We describe 5 to 18 mu m broadband images and R similar to 100 spectra of comet Hale-Bopp taken with SpectroCam-10 on the 5 m Hale telescope during six runs between 1996 June and 1997 April. Our data show the gradual warming of dust grains as the comet approached perihelion. In June, the 10 mu m silicate emission feature was already stronger than observed in any other comet, and it increased to about 3 times the continuum level near perihelion. Spectral structure attributed to a crystalline olivine grain component remained relatively constant, but other features associated with pyroxenes appeared to vary with heliocentric distance. C1 Cornell Univ, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hayward, TL (reprint author), Cornell Univ, 226 Space Sci Bldg, Ithaca, NY 14853 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 265 EP 270 DI 10.1023/A:1006217503964 PG 6 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400041 ER PT J AU Wooden, DH Harker, DE Woodward, CE Koike, C Butner, HM AF Wooden, DH Harker, DE Woodward, CE Koike, C Butner, HM TI Discovery of Mg-rich pyroxenes in comet C/1995 O1 (Hale-Bopp): Pristine grains revealed at perihelion SO EARTH MOON AND PLANETS LA English DT Article; Proceedings Paper CT 1st International Conference on Comet Hale-Bopp CY FEB 02-05, 1998 CL TENERIFE, SPAIN DE comet; infrared; dust; silicates; olivine; pyroxene ID INTERPLANETARY DUST PARTICLES; MINERALOGY; P/HALLEY; OLIVINE; SPECTRA AB The NASA Ames HIFOGS spectrometer observed comet C/1995 O1 (Hale-Bopp) at epochs including 96 Oct 7-14 UT (2.8 AU), 97 Feb 14-15 UT (1.2 AU), 97 Apr 11 UT (0.93 AU), and 97 Jun 22, 25 UT (1.7 AU). The HIFOGS 7.5-13.5 mu m spectrophotometry (R = 360 - 180) of the silicate feature at 2.8 AU is identical in shape to the ISO SWS spectra of comet Hale-Bopp (Crovisier et al., 1997); the strong 11.2 mu m peak in the structured silicate feature is identified as olivine. Upon close passage to the sun, the HIFOGS spectra at 1.2 AU and 0.93 AU reveals strong peaks at 9.3 mu m and 10.0 mu m. The post-perihelion 10 mu m silicate feature at 1.7 AU is weaker but has nearly the same shape as the pre-perihelion spectra at 1.2 AU, reverting to its pre-perihelion shape: there is no change in the dust chemistry by close passage to the sun. The appearance of the strong peaks at 9.3 mu m and 10.0 mu m at r(h) less than or similar to 1.7 AU is attributed to the rise in the contribution of pryoxenes (clino-pyroxene and orthopyroxene crystals) to the shape of the feature, and leads to the hypothesis that the pyroxenes are significantly cooler than the olivines. The pyroxenes are radiating on the Wien side of the blackbody at 2.8 AU and transition to the Rayleigh-Jeans tail of the blackbody upon closer approach to the Sun. Composite fits to the observed 10 mu m silicate features using IDPs and laboratory minerals shows that a good empirical fit to the spectra is obtained when the pryoxenes are about 150 K cooler than the olivines. The pyroxenes, because they are cooler and contribute signficantly at perihelion, are more abundant than the olivines. The perihelion temperature of the pyroxenes implies that the pyroxenes are more Mg-rich than the other minerals including the olivines, amorphous olivines, and amorphous pyroxenes. The PUMA-1 flyby measurements of comet P/Halley also indicated an overabundance of Mg-rich pryoxenes compared to olivines. Comet Hale-Bopp's pyroxenes are similar to pyroxere IDPs from the 'Spray' class, known for their D-richness and their unaltered morphologies: Hale-Bopp's Mg-rich pyroxenes may be pristine relic ISM grains. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Wyoming, Dept Phys & Astron, Wyoming Infrared Observ, Laramie, WY 82071 USA. Kyoto Pharmaceut Univ, Kyoto 607, Japan. Univ Arizona, Submillimeter Telescope Observ, Tucson, AZ 85721 USA. RP Wooden, DH (reprint author), NASA, Ames Res Ctr, MS 243-3, Moffett Field, CA 94035 USA. OI Harker, David/0000-0001-6397-9082; Butner, Harold/0000-0003-4899-2064 NR 24 TC 4 Z9 4 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-9295 J9 EARTH MOON PLANETS JI Earth Moon Planets PY 1997 VL 78 IS 1-3 BP 285 EP 291 DI 10.1023/A:1006225722620 PG 7 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 291GU UT WOS:000085726400044 ER EF