FN Thomson Reuters Web of Science™ VR 1.0 PT B AU Juhasz, AJ AF Juhasz, AJ GP AIAA AIAA TI An analysis and procedure for determining space environmental sink temperatures with selected computational results SO 35TH INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE & EXHIBIT (IECEC), VOLS 1 AND 2, TECHNICAL PAPERS LA English DT Proceedings Paper CT 35th Intersociety Energy Conversion Engineering Conference and Exhibit (IECEC) CY JUL 24-28, 2000 CL Las Vegas, NV SP Amer Inst Aeronaut & Astronaut AB The purpose of this paper is to analyze the heat transfer problem posed by the determination of spacecraft temperatures and to incorporate the theoretically derived relationships into a computational code. Subject code is based on a theoretical analysis of thermal radiative equilibrium in space, particularly in the Solar System. Starting with the solar luminosity, the code takes into account a number of key variables, namely: the spacecraft-to-Sun distance expressed in AU (Astronomical Units), with 1 AU representing the average Sun-to-Earth distance of 149.6 million km; the angle (degrees of are) at which solar radiation is incident on a spacecraft surface, the temperature of which is to be determined (i.e., a radiator or PV (photovoltaic) array); the absorptivity-to-emissivity ratio of the surface, alpha/epsilon, with respect to sol ar radiation; and the view factor of the surface to space. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Juhasz, AJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-375-5 PY 2000 BP 1175 EP 1183 PG 9 WC Engineering, Aerospace SC Engineering GA BQ77B UT WOS:000089466900155 ER PT B AU Schreiber, JG AF Schreiber, JG GP AIAA AIAA TI Assessment of the free-piston Stirling convertor as a long life power convertor for space SO 35TH INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE & EXHIBIT (IECEC), VOLS 1 AND 2, TECHNICAL PAPERS LA English DT Proceedings Paper CT 35th Intersociety Energy Conversion Engineering Conference and Exhibit (IECEC) CY JUL 24-28, 2000 CL Las Vegas, NV SP Amer Inst Aeronaut & Astronaut AB There is currently a renewed interest in the use of free-piston Stirling power convertors for space power applications. More specifically, the Stirling convertor is being developed to be part of the Stirling Radioisotope Power System to supply electric power to spacecraft for NASA deep space science missions. The current development effort involves the Department of Energy, Germantown, MD, the NASA Glenn Research Center, Cleveland, OH, and the Stirling Technology Company, Kennewick, WA. The Stirling convertor will absorb heat supplied from the decay of plutonium dioxide contained in the General Purpose Heat Source modules and convert it into electricity to power the spacecraft. For many years the "potentials" of the free-piston Stirling convertor have been publicized by it's developers. Among these "potentials" were long life and high reliability. This paper will present an overview of the critical areas that enable long life of the free-piston Stirling power convertor, and present some of the techniques that have been used when long life has been achieved. C1 NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH USA. RP Schreiber, JG (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-375-5 PY 2000 BP 1239 EP 1247 PG 9 WC Engineering, Aerospace SC Engineering GA BQ77B UT WOS:000089466900163 ER PT B AU Choi, SH Golembiewski, WT Song, KD AF Choi, SH Golembiewski, WT Song, KD GP AIAA AIAA TI Networked rectenna array for smart material actuators SO 35TH INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE & EXHIBIT (IECEC), VOLS 1 AND 2, TECHNICAL PAPERS LA English DT Proceedings Paper CT 35th Intersociety Energy Conversion Engineering Conference and Exhibit (IECEC) CY JUL 24-28, 2000 CL Las Vegas, NV SP Amer Inst Aeronaut & Astronaut ID SURFACE AB The concept of microwave-driven smart material actuators is envisioned as the best option to alleviate the complexity associated with hard-wired control circuitry. Networked rectenna patch array receives and converts microwave power into a DC power for an array of smart actuators. To use microwave power effectively, the concept of a power allocation and distribution (PAD) circuit is adopted for networking a rectenna/actuator patch array. The PAD circuit is imbedded into a single embodiment of rectenna and actuator array. The thin-film microcircuit embodiment of PAD circuit adds insignificant amount of rigidity to membrane flexibility. Preliminary design and fabrication of PAD circuitry that consists of a few nodal elements were made for laboratory testing. The networked actuators were tested to correlate the network coupling effect, power allocation and distribution, and response time. The features of preliminary design are 16-channel computer control of actuators by a PCI board and the compensator for a power failure or leakage of one or more rectennas. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Choi, SH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-375-5 PY 2000 BP 1449 EP 1457 PG 9 WC Engineering, Aerospace SC Engineering GA BQ77B UT WOS:000089466900190 ER PT B AU Golliher, EL Pepper, SV AF Golliher, EL Pepper, SV GP AIAA AIAA TI Organic materials ionizing radiation susceptibility for the outer planet/solar probe radioisotope power source SO 35TH INTERSOCIETY ENERGY CONVERSION ENGINEERING CONFERENCE & EXHIBIT (IECEC), VOLS 1 AND 2, TECHNICAL PAPERS LA English DT Proceedings Paper CT 35th Intersociety Energy Conversion Engineering Conference and Exhibit (IECEC) CY JUL 24-28, 2000 CL Las Vegas, NV SP Amer Inst Aeronaut & Astronaut AB The Department of Energy is considering the current Stirling Technology Corporation 55 We Stirling Technology Demonstration Convertor as a baseline option for an advanced radioisotope power source for the Outer Planets/Solar Probe project of Jet Propulsion Laboratory and other missions. However, since the Technology Demonstration Convertor contains organic materials chosen without any special consideration of flight readiness, and without any consideration of the extremely high radiation environment of Europa, a preliminary investigation was performed to address the radiation susceptibility of the current organic materials used in the Technology Demonstration Convertor. This report documents the results of the investigation. The results of the investigation show that candidate replacement materials have been identified to be acceptable in the harsh Europa radiation environment. C1 NASA, John A Glenn Res Ctr, Cleveland, OH USA. RP Golliher, EL (reprint author), NASA, John A Glenn Res Ctr, Lewis Field, Cleveland, OH USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-375-5 PY 2000 BP 1491 EP 1496 PG 6 WC Engineering, Aerospace SC Engineering GA BQ77B UT WOS:000089466900194 ER PT B AU Chau, SN Alkalai, L Tai, AT AF Chau, SN Alkalai, L Tai, AT GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Analysis of a multi-layer fault-tolerant COTS architecture for deep space missions SO 3RD IEEE SYMPOSIUM ON APPLICATION SPECIFIC SYSTEMS AND SOFTWARE ENGINEERING TECHNOLOGY, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Symposium on Application-Specific Systems and Software Engineering Technology CY MAR 24-25, 2000 CL RICHARDSON, TX SP IEEE, Comp Soc, Univ Texas, Ctr Applicat Specific Syst & Software Engn AB Fault-tolerant systems are traditionally divided into fault containment regions and custom logic is added to ensure the effects of a fault within a containment region would not propagate to the other regions. This technique may not be applicable in a commercial-off-the-shelf (COTS) based system. While COTS technology is attractive due to its low cost. they are nor developed with the same level of rigorous fault tolerance in mind. Furthermore, COTS suppliers usually have no interest to add any overhead or sacrifice performance to implement fault-tolerance for a narrow market of high reliability applications. To over come this shortcoming, Jet Propulsion Laboratory (JPL) has developed a multi-layer fault protection methodology to achieve high reliability ill COTS-based avionics systems. This methodology has been applied to the bus architecture that uses the COTS bus interface standards IEEE 1394 and (IC)-C-2. This paper-first gives an overview of the multi-layer fault-protection design methodology for COTS-based mission-critical systems. Then the effectiveness of the methodology is analyzed in terms of coverage and cost. The results ale compared to the traditional custom designed system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chau, SN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 4 Z9 4 U1 1 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0559-7 PY 2000 BP 70 EP 76 DI 10.1109/ASSET.2000.888035 PG 7 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BR13Y UT WOS:000165731400010 ER PT B AU Feather, MS Cornford, SL Gibbel, M AF Feather, MS Cornford, SL Gibbel, M GP IEEE IEEE TI Scalable mechanisms for requirements interaction management SO 4TH INTERNATIONAL CONFERENCE ON REQUIREMENTS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 4th International Conference on Requirements Engineering (ICRE 2000) CY JUN 19-23, 2000 CL SCHAUMBURG, IL SP IEEE Comp Soc Tech Concil Software Engn, Fujitsu, Lucent Technologies, Rational AB Capturing requirements, and managing tradeoffs among them, are critical yet complex activities. Well-designed computerized tools can effectively support these activities. A key challenge ita construction of these support tools is how to scale them to handle a large volume of information. Particularly, crucial are the ways ill which large numbers of requirements and their interrelationships are presented to users. They need to be able to zoom ira and out through the space of information so as to be able ro see the big picture, and to locate and focus on specific details when needed. This paper describes a harmonious combination of techniques that support such scalability. The techniques have been embodied in a NASA tool, DDP, for defect detection and prevention. They have been exercised in uses of this tool for requirements/risk tradeoffs, and population of this tool to capture institutional knowledge-bases of information. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Feather, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 13 Z9 13 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0565-1 PY 2000 BP 119 EP 129 DI 10.1109/ICRE.2000.855598 PG 11 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BQ52X UT WOS:000088653100020 ER PT B AU Ghaffarian, R Kim, NP AF Ghaffarian, R Kim, NP GP IEEE IEEE TI CSP assembly reliability and effects of underfill and double-sided population SO 50TH ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE - 2000 PROCEEDINGS SE PROCEEDINGS - ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE LA English DT Proceedings Paper CT 50th Electronic Components & Technology Conference (ECTC 01) CY MAY 21-24, 2000 CL LAS VEGAS, NV SP IEEE, IEEE Components, Packaging & Mfg Technol Soc, Electe Indust Alliance, ECA Electr Components, Assemblies, & Mat Assoc AB The JPL-led MicrotypeBGA Consortium of enterprises representing government agencies and private companies have jointed together to pool in-kind resources for developing the quality and reliability of chip scale packages (CSPs) for a variety of projects[ll. In the process of building the Consortium CSP test vehicles, many challenges were identified regarding various aspects of technology implementation. Last year, ball shear test results before and after isothermal aging were presented and compared to ball grid array packages[ll. These package were assembled on single- and double sided printed circuit board (PWB) without and with underfill. These test vehicles are subjected to various environmental tests including four thermal cycling conditions. These cycles represent the extreme harsh accelerated testing in the range of -55 to 125 degrees C to a commercial requirement in the range of 0 to 100 degrees C. This paper presents the thermal cycling test results to 2,000 cycles performed under different environmental conditions for single- and double-sided assemblies with and without underfill. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Reza.Ghaffarian@JPL.NASA.Gov NR 6 TC 10 Z9 10 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5908-9 J9 P ELECTR C PY 2000 BP 390 EP 396 DI 10.1109/ECTC.2000.853183 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA BQ45U UT WOS:000088390200065 ER PT B AU Ramesham, R Ghaffarian, R AF Ramesham, R Ghaffarian, R GP IEEE IEEE TI Challenges in interconnection and packaging of microelectromechanical systems (MEMS) SO 50TH ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE - 2000 PROCEEDINGS SE PROCEEDINGS - ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE LA English DT Proceedings Paper CT 50th Electronic Components & Technology Conference (ECTC 01) CY MAY 21-24, 2000 CL LAS VEGAS, NV SP IEEE, IEEE Components, Packaging & Mfg Technol Soc, Electe Indust Alliance, ECA Electr Components, Assemblies, & Mat Assoc DE interconnections; packaging; commercial-off-the-shelf; microelectromechanical systems; MEMS; COTS; quality assurance; reliability; and space environment ID RELIABILITY; SURFACE; SENSORS; VACUUM AB Integrated circuit packaging and their testing is well advanced because of the maturity of the IC industry, their wide applications, and availability of industrial infrastructure. [1,2] This is not true for MEMS with respect to packaging and testing. It is more difficult to adopt standardized MEMS device packaging for wide applications although MEMS use many similar technologies to IC packaging. Packaging of MEMS devices is more complex since in some cases it needs to provide protection from the environment while in some cases allowing access to the environment to measure or affect the desired physical or chemical parameters. Microscopic mechanical moving parts of MEMS have also their unique issues. Therefore, testing MEMS packages using the same methodologies, as those for electronics packages with standard procedures might not always be possible especially when quality and reliability need to be assessed. Single MEMS chip packaging approaches and their limitations in the packaging of high performance MEMS will be reviewed in this presentation and also identifies a need for a systematic approach for this purpose. MEMS package reliability depends on package type, i.e. ceramic, plastic, or metal, and reliability of device. The MEMS device reliability depends on its materials and wafer level processes and sealing methods used for environmental protection. MEMS quality and reliability challenges are discussed and needs for study in these areas are identified. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 125-152, Pasadena, CA 91109 USA. EM Rajeshuni.Ramesham@jpl.nasa.gov NR 70 TC 35 Z9 38 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5908-9 J9 P ELECTR C PY 2000 BP 666 EP 675 DI 10.1109/ECTC.2000.853230 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA BQ45U UT WOS:000088390200111 ER PT B AU Bergman, LA Yeh, C Morookian, J AF Bergman, LA Yeh, C Morookian, J GP IEEE IEEE TI Advances in multi-channel optical multi-gbytes/sec bit-parallel WDM single fiber link SO 50TH ELECTRONIC COMPONENTS & TECHNOLOGY CONFERENCE - 2000 PROCEEDINGS SE PROCEEDINGS - ELECTRONIC COMPONENTS AND TECHNOLOGY CONFERENCE LA English DT Proceedings Paper CT 50th Electronic Components & Technology Conference (ECTC 01) CY MAY 21-24, 2000 CL LAS VEGAS, NV SP IEEE, IEEE Components, Packaging & Mfg Technol Soc, Electe Indust Alliance, ECA Electr Components, Assemblies, & Mat Assoc ID DIVISION-MULTIPLEXED BEAMS; NONLINEAR FIBER; PULSE AB For ultra-high-speed single media parallel interconnects, an all optical single fiber WDM format of transmitting parallel bits rather than a fiber ribbon format-where parallel bits are sent through corresponding parallel fibers in a ribbon format, can be the media of choice. Here, we shall discuss the realization of a multi-km x gbytes/sec bit-parallel WDM (BP-WDM) single fiber link. The distance-speed product of this single fiber link is more than several orders of magnitude higher than that of a fiber ribbon link. The design of a 12 bit-parallel channels WDM system operating at 1 Gbit/sec per channel rate through a single fiber will first be presented. Experimental results for a two channel system operating at that rate are given. Further improvement of distance-speed product for the BP-WDM link can be obtained with JPL's newly developed 20 Gbits/sec per channel laser diode array transmitter. Also, new computer simulation results on how a large amplitude co-propagating pulse may induce pulse compression on ail the co-propagating data pulses, thereby improving the shaping of these pulses for a WDM system, will be presented and discussed. The existence of WDM solitons is also shown. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bergman, LA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-5908-9 J9 P ELECTR C PY 2000 BP 1504 EP 1510 DI 10.1109/ECTC.2000.853413 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA BQ45U UT WOS:000088390200244 ER PT B AU Rayner, M Hockey, BA James, F AF Rayner, M Hockey, BA James, F GP acl TI A compact architecture for dialogue management based on scripts and meta-outputs SO 6TH APPLIED NATURAL LANGUAGE PROCESSING CONFERENCE/1ST MEETING OF THE NORTH AMERICAN CHAPTER OF THE ASSOCIATION FOR COMPUTATIONAL LINGUISTICS, PROCEEDINGS OF THE CONFERENCE AND PROCEEDINGS OF THE ANLP-NAACL 2000 STUDENT RESEARCH WORKSHOP LA English DT Proceedings Paper CT 6th Applied Natural Language Processing Conference/1st Meeting of the North American Chapter of the Association-for-Computational-Linguistics/ANLP-NAACL 2000 Student Research Workshop CY APR 29-MAY 04, 2000 CL Seattle, WA SP Assoc Computat Linguist, N Amer Chapter AB We describe an architecture for spoken dialogue interfaces to semi-autonomous systems that transforms speech signals through successive representations of linguistic, dialogue, and domain knowledge. Each step produces an output, and a meta-output describing the transformation, with an executable program in a simple scripting language as the final result. The output/meta-output distinction permits perspicuous treatment of diverse tasks such as resolving pronouns, correcting user misconceptions, and optimizing scripts. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. RP Rayner, M (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Mail Stop 19-39, Moffett Field, CA 94035 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU ASSOCIATION COMPUTATIONAL LINGUISTICS PI SOMERSET PA PO BOX 6090, SOMERSET, NJ 08875 USA BN 1-55860-704-8 PY 2000 BP 112 EP 118 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications; Linguistics SC Computer Science; Linguistics GA BAP09 UT WOS:000223099500016 ER PT S AU Reames, DV AF Reames, DV BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI The observational consequences of proton-generated waves at shocks SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID SOLAR ENERGETIC PARTICLES; CORONAL MASS EJECTIONS; MEAN IONIC CHARGE; ACCELERATION; FLARES; EVENTS; TRANSPORT AB In the largest solar energetic particle (SEP) events, acceleration takes place at shock waves driven out from the Sun by fast coronal mass ejections. Protons streaming away from strong shocks generate Alfven waves that trap particles in the acceleration region, limiting outflowing intensities but increasing the efficiency of acceleration to higher energies. Early in the events, with the shock still near the Sun, intensities at 1 AU are bounded and spectra are flattened at low energies. Elements with different charge-to-mass ratios, Q/A, differentially probe the wave spectra near shocks, producing abundance ratios that vary in space and time. An initial rise in He/H, while Fe/O declines, is a typical symptom of the non-Kolmogorov wave spectra in the largest events. Strong wave generation can cause cross-field scattering near the shock and unusually rapid reduction in anisotropies even far from the shock. At the highest energies, shock spectra steepen to form a "knee." For protons, this spectral knee can vary from similar to 10 MeV to similar to1 GeV depending on shock conditions for wave growth. In one case, the location of the knee scales approximately as Q/A in the energy/nucleon spectra of other species. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reames, DV (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 79 EP 86 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000009 ER PT S AU Slocum, PL Wiedenbeck, ME Cohen, CMS Christian, ER Cummings, AC Leske, RA Mewaldt, RA Stone, EC AF Slocum, PL Wiedenbeck, ME Cohen, CMS Christian, ER Cummings, AC Leske, RA Mewaldt, RA Stone, EC BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Measurements of heavy elements in He-3-rich SEP events SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID PARTICLE EVENTS; SOLAR; HE-3; ABUNDANCES; FLARES AB Using the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE), we have studied the properties of a selection of small He-3-rich solar energetic particle (SEP) events with heavy ion enhancements in the energy range similar to 11-22 MeV/nucleon. These events contain significantly increased He-3/He-4 ratios over the solar wind value of 0.0004 in the energy range similar to4.5-5.5 MeV/nucleon. In order to characterize the events, the following features have been investigated. First, the heavy element content has been measured and compared to that found in past studies of impulsive SEP events. Next, the simultaneous 38-53 keV electron flux, measured with the Electron, Proton, and Alpha Monitor (EPAM) on ACE, has been examined for possible activity near the He-3-rich event onset times. Finally a list of measured solar X-ray flares, with corresponding H-alpha flares where possible, has been scrutinized for potential correlations with these events. The results show an apparent correlation between event onset and increased electron flux, and a possible association with X-ray flares. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Slocum, PL (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 103 EP 106 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000014 ER PT S AU Wiedenbeck, ME Christian, ER Cohen, CMS Cummings, AC Leske, RA Mewaldt, RA Slocum, PL Stone, EC von Rosenvinge, TT AF Wiedenbeck, ME Christian, ER Cohen, CMS Cummings, AC Leske, RA Mewaldt, RA Slocum, PL Stone, EC von Rosenvinge, TT BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Enhanced abundances of He-3 in large solar energetic particle events SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team AB Observations of a number of relatively large solar energetic particle (SEP) events that have occurred since the launch of ACE in August 1997 have shown that the ratio of He-3/He-4 can be enhanced over the solar wind value (similar to 4 x 10(-4)) by more than an order of magnitude in such events. Since particle acceleration in these "gradual" SEP events is thought to be caused by CME-driven shocks traveling through the solar corona and interplanetary medium, a source of He-3 in addition to the solar wind appears required to provide the seed material. Using data from the Solar Isotope Spectrometer on ACE, we have carried out a more detailed investigation of the characteristics of the He-3 enhancements at energies > 5 MeV/nucleon in three large SEP events (4 Nov 1997, 6 May 1998, and 14 Nov 1998). We find that the He-3/He-4 ratios are essentially time-independent during the events, that the He-3 energy spectra are markedly harder than those commonly observed in impulsive events, and that the spectra of He-3 may be harder than those of He-4. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Wiedenbeck, ME (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 13 TC 16 Z9 16 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 107 EP 110 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000015 ER PT S AU von Rosenvinge, TT Cohen, CMS Christian, ER Cummings, AC Leske, RA Mewaldt, RA Slocum, PL Stone, EC Wiedenbeck, ME AF von Rosenvinge, TT Cohen, CMS Christian, ER Cummings, AC Leske, RA Mewaldt, RA Slocum, PL Stone, EC Wiedenbeck, ME BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI The solar energetic particle event of 6 May 1998 SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID IONIC CHARGE; ABUNDANCES; ENERGIES; NUCLEON; SAMPEX AB The abundances of elements from helium to iron have been measured in more than a dozen moderate to large solar energetic particle (SEP) events using the Solar Isotope Spectrometer (SIS) on-board the Advanced Composition Explorer (ACE). Time variations within some of these events and from event to event have been reported previously. This paper presents an analysis of the event of 6 May 1998, for which relatively time-independent abundance ratios are found. This event has been considered to be an example of an impulsive event, a gradual event, and as a hybrid of the two. Difficulties with classifying this event are discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP von Rosenvinge, TT (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 20 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 111 EP 114 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000016 ER PT S AU Ramaty, R Lenters, G Mandzhavidze, N Miller, JA AF Ramaty, R Lenters, G Mandzhavidze, N Miller, JA BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Gamma-ray evidence for time-dependent heavy ion enhancement in a solar flare SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP Conference Proceedings LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID ENERGY; ACCELERATION; DISSIPATION; EMISSION; CASCADE AB We briefly review the gamma-ray data of the 1991 June 1 Rare and the analysis which provide evidence that the accelerated ion composition is that observed from impulsive hares and that the heavy ion enrichment, characteristic of impulsive flares, increased during the course of the Rare as the gamma-ray fluxes decreased. We propose that this anti correlation is due to acceleration by cascading Alfven turbulence. We also show that a large behind-the-limb flare, such as the June 1 event, could produce detectable gamma-ray line emission as the radioactive patch which it creates rotates onto the visible solar disk. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ramaty, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM ramaty@gsfc.nasa.gov; millerj@cspar.uah.edu NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 119 EP 122 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000018 ER PT S AU Tsurutani, BT Zhang, LD Mason, G Lakhina, GS Hada, T Arballo, JK Zwickl, RD AF Tsurutani, BT Zhang, LD Mason, G Lakhina, GS Hada, T Arballo, JK Zwickl, RD BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Solar energetic He-3 mean free paths: Comparison between wave-particle and particle anisotropy results SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID COSMIC-RAY TRANSPORT; PITCH-ANGLE DIFFUSION; QUASI-LINEAR THEORY; INTERPLANETARY DISCONTINUITIES; ALFVEN WAVES; ACCELERATION; PROPAGATION; ULYSSES; EVENTS; IONS AB Energetic He-3 particle mean free paths are calculated using in-situ wave amplitudes. The wave polarization (outward propagating, are-polarized, spherical) and wave k directions (outward hemispherical) are included in a first-order cyclotron resonant calculation. Values for lambda (W-P) are similar to0.2 AU. This is roughly similar to5 times smaller than the particle mean free path as determined from modeling applied to measured front-to-back He-3 particle anisotropies. It is suggested that this difference is due to much slower pitch angle diffusion through 90 degrees. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Lakhina, Gurbax /C-9295-2012 NR 26 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 165 EP 168 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000029 ER PT S AU Liewer, PC Velli, M Goldstein, BE AF Liewer, PC Velli, M Goldstein, BE BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Hybrid simulations of preferential heating of heavy ions in the solar wind SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID ACCELERATION AB We present results from the first fully self-consistent 1D hybrid (kinetic ions/fluid electrons) simulations of the preferential heating of alphas and heavier minor ions by a flat spectrum of Alfven-ion cyclotron waves in a collisionless plasma. We find that the simulations reproduce the observed solar wind scaling T proportional to M for alphas and heavier minor ions when the alphas and the minor ions have equal charge to mass ratios, q/M, and equal initial thermal velocities, V-th = (T/M)(1/2). This scaling is interpreted as a result of the basic physics: the time evolution of the Vlasov/Maxwell system without collisions depends only on the ratio q/M and not q or M separately. Because this result follows from the basic nature of the physical model, the T proportional to M scaling would be obtained for any spectrum of waves. For minor ions with q/M different from the alphas but equal initial thermal velocities, the final thermal velocity is seen to vary by +/-50% from that of the alphas in the simulations presented here. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liewer, PC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 274 EP 277 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000049 ER PT S AU Christian, ER Binns, WR Cohen, CMS Cummings, AC George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Slocum, PL Stone, EC von Rosenvinge, TT Wiedenbeck, ME Yanasak, N AF Christian, ER Binns, WR Cohen, CMS Cummings, AC George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Slocum, PL Stone, EC von Rosenvinge, TT Wiedenbeck, ME Yanasak, N BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Time variations of the modulation of anomalous and galactic cosmic rays SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID ADVANCED-COMPOSITION-EXPLORER; MAGNETIC-FIELD; ISOTOPE SPECTROMETER; HELIOSPHERE AB Between the launch of the Advanced Composition Explorer (ACE) in 1997 and the end of 1999, the intensities of galactic cosmic rays at 1 AU have dropped almost a factor of 2, and the anomalous cosmic rays have decreased by an even larger amount. The large collecting power of the Cosmic Ray Isotope Spectrometer (CRIS) and the Solar Isotope Spectrometer (SIS) instruments on ACE allow us to investigate the changing modulation on short time scales and at different rigidities. Using anomalous cosmic ray (ACR) and galactic cosmic ray (GCR) intensities of He, C, O, Ne, Si, S, and Fe, and energies from similar to 6 MeV/nndeon to similar to 460 MeV/nucleon, we examine the differences between the short term and long term effects. We observe the expected correlation of these intensities with neutron monitor data, but see little correlation of GCR and ACR intensities with the locally measured magnetic field. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Christian, ER (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 11 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 353 EP 356 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000063 ER PT S AU Wiedenbeck, ME Binns, WR Christian, ER Cummings, AC George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Stone, EC von Rosenvinge, TT Yanasak, NE AF Wiedenbeck, ME Binns, WR Christian, ER Cummings, AC George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Stone, EC von Rosenvinge, TT Yanasak, NE BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Constraints on cosmic-ray acceleration and transport from isotope observations SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID INTERSTELLAR-MEDIUM; SUPERNOVA-REMNANTS; ELEMENTS; NUCLEOSYNTHESIS; ABUNDANCES; EVOLUTION; NUCLEI; SOLAR; TIME; FE AB Observations from the Cosmic Ray Isotope Spectrometer (CRIS) on ACE have been used to derive constraints on the locations, physical conditions, and time scales for cosmic-ray acceleration and transport. The isotopic composition of Fe, Co, and Ni is very similar to that of solar system material, indicating that cosmic rays contain contributions from supernovae of both Type II and Type la. The electron-capture primary Ni-59 produced in supemovae has decayed, demonstrating that a time greater than or similar to 10(5) yr elapses before acceleration of the bulk of the cosmic rays and showing that most of the accelerated material is derived from old stellar or interstellar material rather than from fresh supernova ejecta. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Wiedenbeck, ME (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 28 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 363 EP 370 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000065 ER PT S AU Yanasak, NE Binns, WR Christian, ER Cummings, AC Davis, AJ George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Stone, EC von Rosenvinge, TT Wiedenbeck, ME AF Yanasak, NE Binns, WR Christian, ER Cummings, AC Davis, AJ George, JS Hink, PL Klarmann, J Leske, RA Lijowski, M Mewaldt, RA Stone, EC von Rosenvinge, TT Wiedenbeck, ME BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI Abundances of the cosmic ray beta-decay secondaries and implications for cosmic ray transport SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID ISOTOPIC COMPOSITION; PROPAGATION; ELEMENTS; GALAXY; NUCLEI; SOLAR; BE-10; AGE AB Galactic cosmic rays (GCRs) pass through the interstellar medium (ISM) and undergo nuclear interactions that produce secondary fragments. The abundances of radioactive secondary species can be used to derive a galactic confinement time for cosmic rays using the amount of ISM material traversed by the cosmic rays inferred from stable GCR secondary abundances. Abundance measurements of long-lived species such as Be-10, Al-26, Cl-36, and Mn-54 allow a comparison of propagation histories for different parent nuclei. Abundances for these species, measured in the energy range similar to 50 - 500 MeV/nuc using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE) spacecraft, indicate a confinement time tau (esc) = 16.2+/-0.8 Myr. We have modeled the production and propagation of the radioactive secondaries and discuss the implications for GCR transport. C1 Jet Propuls Lab, Pasadena, CA 91109 USA. RP Yanasak, NE (reprint author), Jet Propuls Lab, Pasadena, CA 91109 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 24 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 402 EP 405 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000071 ER PT S AU Ormes, JF Digel, S Moskalenko, IV Moiseev, A Williamson, R AF Ormes, JF Digel, S Moskalenko, IV Moiseev, A Williamson, R CA GLAST Collaboration BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI The origin of cosmic rays: What can GLAST say? SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID SUPERNOVA-REMNANTS; SHOCK ACCELERATION; EGRET OBSERVATIONS; ELECTRONS; RADIO; EMISSION; SPECTRUM AB Gamma rays in the band from 30 MeV to 300 GeV, used in combination with direct measurements and with data from radio and X-ray bands, provide a powerful tool for studying the origin of Galactic cosmic rays. Gamma-ray Large Area Space Telescope (GLAST) with its fine 10-20 arcmin angular resolution will be able to map the sites of acceleration of cosmic rays and their interactions with interstellar matter. it will provide information that is necessary to study the acceleration of energetic particles in supernova shocks, their transport in the interstellar medium and penetration into molecular clouds. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ormes, JF (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Moskalenko, Igor/A-1301-2007 OI Moskalenko, Igor/0000-0001-6141-458X NR 26 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 445 EP 448 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000082 ER PT S AU Digel, SW Moskalenko, IV Ormes, JF Sreekumar, P Williamson, PR AF Digel, SW Moskalenko, IV Ormes, JF Sreekumar, P Williamson, PR CA GLAST Collaboration BE Mewaldt, RA Jokipii, JR Lee, MA Mobius, E Zurbuchen, TH TI What can GLAST say about the origin of cosmic rays in other galaxies? SO ACCELERATION AND TRANSPORT OF ENERGETIC PARTICLES OBSERVED IN THE HELIOSPHERE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT ACE 2000 Symposium on Acceleration and Transport of Energetic Particles Observed in the Heliosphere CY JAN 05-08, 2000 CL INDIAN WELLS, CA SP ACE, Sci Working Team ID LARGE-MAGELLANIC-CLOUD; GAMMA-RAYS; EMISSION; PULSARS AB Gamma rays in the band from 20 MeV to 300 GeV, used in combination with data from radio and Xray bands, provide a powerful tool for studying the origin of cosmic rays in our sister galaxies Andromeda and the Magellanic Clouds. Gamma-ray Large Area Space Telescope (GLAST) will spatially resolve these galaxies and measure the spectrum and intensity of diffuse gamma radiation from the collisions of cosmic rays with gas and dust in them. Observations of Andromeda will give an external perspective on a spiral galaxy like the Milky Way. Observations of the Magellanic Clouds will permit a study of cosmic rays in dwarf irregular galaxies, where the confinement is certainly different and the massive star formation rate is much greater. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Digel, SW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Moskalenko, Igor/A-1301-2007 OI Moskalenko, Igor/0000-0001-6141-458X NR 12 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-951-3 J9 AIP CONF PROC PY 2000 VL 528 BP 449 EP 452 PG 4 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BQ94U UT WOS:000165073000083 ER PT J AU Farrell, WM Desch, MD Kaiser, ML Houser, J Landis, GA Wilt, DM AF Farrell, WM Desch, MD Kaiser, ML Houser, J Landis, GA Wilt, DM TI Radio and optical detection of Martian dust storm discharges SO ACTA ASTRONAUTICA LA English DT Article ID MARS; WHISTLERS; DEVILS; MODEL AB Given the known physical attributes of Martian dust storms, we derive their electromagnetic signatures as they would be perceived both remotely and in situ. We also describe a radiowave and optical experiment (REDD), suitable for deployment on the Mars Surveyor 2001 Lander, whose primary scientific objective is to establish the electrical nature of dust storms in the Martian atmosphere. This experiment would be capable of the remote tracking of dust storms across the Martian surface while estimating electrical properties of dust, dust densities, and surface conductivities. The experiment sensors consist of two orthogonal magnetic search coil antennas, an electric field antenna, and a horizon-looking photodetector. The sensors drive a waveform capture system and a set of multichannel analyzers that span the radio spectrum from 1 kHz to 100 MHz. The data sampling strategy incorporates a low-resolution survey mode and a high rime-resolution direction-finding mode. Intelligent use of an event-trigger system, circular buffer storage, and data compression minimize the instrument data rate and the impact on spacecraft resources. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Farrell, William/I-4865-2013 NR 37 TC 7 Z9 7 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 PY 2000 VL 46 IS 1 BP 25 EP 36 DI 10.1016/S0094-5765(99)00182-4 PG 12 WC Engineering, Aerospace SC Engineering GA 286UQ UT WOS:000085467600003 ER PT J AU Paules, G Luther, M AF Paules, G Luther, M TI NASA's Earth Science program - Increasing science opportunity and payoff through small satellites SO ACTA ASTRONAUTICA LA English DT Article AB By now it is well known that small satellites are the future for NASA's Space and Earth Science missions as we implement the Administrator's challenge for "better/faster/cheaper" missions. Though the Earth Science Enterprise is motivated to reduce overall program costs there are several other driving factors. First, the desire for more frequent science missions. Typically, with each mission scientists learn more and desire to refine and even completely refocus efforts based on the new knowledge. Second, the desire to reduce overall program risk by minimizing losses due to launch, spacecraft, or single instrument failures. And, third, the need to exploit the major advances in technology itself-especially in microelectronics, high performance computing, and sophisticated end-to-end information system concepts By objective NASA's Earth Science program must provide long-term data sets of climate-related and geophysical variables. At the same time it must provide for experimental missions to analyze Earth system processes for the first time. Many of these science investigations require that measurements using different remote sensing techniques be made simultaneously. In the past this has resulted in a number of instruments gathered on a single, large platform such as that for EOS AM-I. ESE has accepted the challenge to accomplish these objectives through the use of smaller satellites, highly advanced instrument technologies, and sophisticated operational concepts. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Off Earth Sci, Washington, DC 20546 USA. RP Paules, G (reprint author), NASA, Off Earth Sci, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2000 VL 46 IS 2-6 BP 61 EP 64 DI 10.1016/S0094-5765(99)00193-9 PG 4 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600003 ER PT J AU Deutsch, LJ Salvo, C Woerner, D AF Deutsch, LJ Salvo, C Woerner, D TI NASA's X2000 program - An institutional approach to enabling smaller spacecraft SO ACTA ASTRONAUTICA LA English DT Article AB The number of NASA science missions per year is increasing from less than one to more than six. Individual mission budgets are smaller, though, so they can no longer afford dedicated technology developments. As a result, NASA formed the X2000 Program. X2000 is divided into a set of "deliveries" that provide basic avionics, power, communications, and software for future missions. X2000 First Delivery, to be completed in 2001, will provide a one MRAD-tolerant flight computer, power switching electronics, efficient radioisotope power source, and a transponder with services at 8.4 GHz and 32 GHz bands. The X2000 Second Delivery, to be completed around 2003, will enable complete spacecraft of 10-50 kg. Capabilities delivered by X2000 will be commercialized within the US so they will be available to others. Although the immediate customers for X2000 are deep space missions, most capabilities are generic in nature and will be equally applicable to Earth Observation missions, (C) 2000 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Adv Flight Syst Program, Pasadena, CA 91125 USA. RP Deutsch, LJ (reprint author), CALTECH, Jet Prop Lab, Adv Flight Syst Program, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 6 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-MAR PY 2000 VL 46 IS 2-6 BP 229 EP 232 DI 10.1016/S0094-5765(99)00203-9 PG 4 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600024 ER PT J AU Alkalai, L AF Alkalai, L TI Advanced microelectronics technologies for future small satellite systems SO ACTA ASTRONAUTICA LA English DT Article AB Future small satellite systems for both Earth observation as well as deep-space exploration are greatly enabled by the technological advances in deep sub-micron microelectronics technologies. Whereas these technological advances are being fueled by the commercial (non-space) industries, more recently there has been an exciting new synergism evolving between the two otherwise disjoint markets. In other words, both the commercial and space industries are enabled by advances in low-power, highly integrated, miniaturized (low-volume), lightweight, and reliable real-time embedded systems. Recent announcements by commercial semiconductor manufacturers to introduce Silicon On Insulator (SOI) technology into their commercial product lines is driven by the need for high-performance low-power integrated devices. Moreover, SOI has been the technology of choice for many space semiconductor manufacturers where radiation requirements are critical. This technology has inherent radiation latch-up immunity built into the process, which makes it very attractive to space applications. In this paper, we describe the advanced microelectronics and avionics technologies under development by NASA's Deep Space Systems Technology Program (also known as X2000). These technologies are of significant benefit to both the commercial satellite as well as the deep-space and Earth orbiting science missions. Such a synergistic technology roadmap may truly enable quick turn-around, low-cost, and highly capable small satellite systems for both Earth observation as well as deep-space missions. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, CISM, Pasadena, CA 91125 USA. RP Alkalai, L (reprint author), CALTECH, Jet Prop Lab, CISM, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 11 TC 5 Z9 5 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-MAR PY 2000 VL 46 IS 2-6 BP 233 EP 239 DI 10.1016/S0094-5765(99)00204-0 PG 7 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600025 ER PT J AU Fang, WC AF Fang, WC TI A low-power high-speed smart sensor design for space exploration missions SO ACTA ASTRONAUTICA LA English DT Article AB A low-power high-speed smart sensor system based on a large format active pixel sensor (APS) integrated with a programmable neural processor for space exploration missions is presented. The concept of building an advanced smart sensing system is demonstrated by a system-level microchip design that is composed with an APS sensor, a programmable neural processor, and an embedded microprocessor ina SOI CMOS technology. This ultra-fast smart sensor system-on-a-chip design mimics what is inherent in biological vision systems. Moreover, it is programmable and capable of performing ultra-fast machine vision processing in all levels such as image acquisition, image fusion, image analysis, scene interpretation, and control functions. The system provides about one tera-operation-per-second computing power which is a two order-of-magnitude increase over that of state-of-the-art microcomputers. Its high performance is due to massively parallel computing structures, high data throughput rates, fast learning capabilities, and advanced VLSI system-on-a-chip implementation. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fang, WC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 2 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-MAR PY 2000 VL 46 IS 2-6 BP 241 EP 250 DI 10.1016/S0094-5765(99)00205-2 PG 10 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600026 ER PT J AU Esper, J Panetta, PV Ryschkewitsch, M Wiscombe, W Neeck, S AF Esper, J Panetta, PV Ryschkewitsch, M Wiscombe, W Neeck, S TI NASA-GSFC Nano-satellite Technology for Earth Science Missions SO ACTA ASTRONAUTICA LA English DT Article DE nano-satellite; micro-satellite; constellation; Earth Science; remote sensing; in-situ measurements AB The NASA-GSFC Nano-satellite Technology Program is currently formulating solutions for 21(st) century Earth Science requirements. We anticipate that nano-satellite (similar to 10 kg) and micro-satellite (10 to 100 kg) constellations will have important applications in both Earth and Space science. Such constellations, acting in unison and with a large degree of autonomy, could form "virtual platforms" of detailed remotely sensed measurements providing orders of magnitude more information than today's thinly-populated networks of LEO and GEO satellites. If the constellations include a variety of basic, versatile instruments, for example UV, VIS and IR hyperspectral spectrometers, then virtual platforms for different applications can be formed in space, on the fly, and "disassembled" later for other uses or to test other scientific hypotheses. Example applications include weather prediction, radiative/reflected energy measurements for global change studies, hazard warning and monitoring systems (fires, volcanoes, hurricanes, etc.), and in-situ measurements of Earth's magnetic field. For a wide range of applications, nano- and micro-satellite technology is likely to further the way NASA explores not only the Earth, but the solar system and beyond. Identifying the strategies and technologies that provide strong benefit to both the Earth and Space science programs will provide the best return on NASA's technology investment. This paper will highlight some possible Earth Science applications for nano- and micro-satellite constellations as well as the current status of planned NASA-GSFC nano/micro-satellite technology development. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Esper, J (reprint author), Swales Aerosp, 5050 Powder Mill Rd, Beltsville, MD 20705 USA. RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 3 TC 16 Z9 19 U1 2 U2 9 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-MAR PY 2000 VL 46 IS 2-6 BP 287 EP 296 DI 10.1016/S0094-5765(99)00214-3 PG 10 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600031 ER PT J AU Yunck, TP Hajj, GA Kursinski, ER LaBrecque, JA Lowe, ST Watkins, MM McCormick, C AF Yunck, TP Hajj, GA Kursinski, ER LaBrecque, JA Lowe, ST Watkins, MM McCormick, C TI AMORE: An autonomous constellation concept for atmospheric and ocean observation SO ACTA ASTRONAUTICA LA English DT Article ID GLOBAL POSITIONING SYSTEM; IONOSPHERE AB The Atmospheric Moisture and Ocean Reflection Experiment-AMORE-is a proposed constellation of microspacecraft for atmospheric and ocean observation. AMORE would observe atmospheric radio occultations and ocean reflections from an array of 12 or more microspacecraft to support climate process studies and the testing and refinement of climate models. The spacecraft would track the L-band signals of 48 GPS and GLONASS satellites, directly and reflected off the ocean, and would exchange occultation crosslinks at 10, 14, 18, and 23 GHz to map tropospheric water vapor from the surface to the tropopause, the detailed refractivity and thermal structure of the global atmosphere, and difficult-to-observe eddy-scale changes in ocean circulation, (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yunck, TP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 3 Z9 3 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-MAR PY 2000 VL 46 IS 2-6 BP 355 EP 364 DI 10.1016/S0094-5765(99)00231-3 PG 10 WC Engineering, Aerospace SC Engineering GA 297CH UT WOS:000086063600040 ER PT S AU Troy, M Dekany, R Brack, G Oppenheimer, B Bloemhof, E Trinh, T Dekens, F Shi, F Hayward, T Brandl, B AF Troy, M Dekany, R Brack, G Oppenheimer, B Bloemhof, E Trinh, T Dekens, F Shi, F Hayward, T Brandl, B BE Wizinowich, PL TI Palomar adaptive optics project: status and performance SO ADAPTIVE OPTICAL SYSTEMS TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical Systems Technology CY MAR 29-31, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE adaptive optics; telescopes; instrumentation; atmospheric characterization ID SYSTEM AB We describe the current performance of the Palomar 200 inch (5 m) adaptive optics system, which in December of 1998 achieved its first high order (241 actuators) lock on a natural guide star. In the K band (2.2 mu m), the system has achieved Strehl ratios as high as 50% in the presence of 1.0 arcsecond seeing (0.5 mu m). Predictions of the system's performance based on the analysis of real-time wavefront sensor telemetry data and a analysis based on a fitted Kolmogorov atmospheric model are shown to both agree with the observed science image performance. Performance predictions for various seeing conditions are presented and an analysis of the error budget is used to show which subsystems limit the performance of the AO system under various atmospheric conditions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Troy, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 101 Z9 101 U1 1 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3632-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4007 BP 31 EP 40 DI 10.1117/12.390302 PN 1&2 PG 10 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BQ70C UT WOS:000089218600004 ER PT S AU Dekany, R Troy, M Brack, G Bleau, C DuVarney, R Ealey, M AF Dekany, R Troy, M Brack, G Bleau, C DuVarney, R Ealey, M BE Wizinowich, PL TI 1600 actuator tweeter mirror upgrade for the Palomar Adaptive Optics System (PALAO) SO ADAPTIVE OPTICAL SYSTEMS TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical Systems Technology CY MAR 29-31, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE deformable mirror; multiconjugate adaptive optics; wavefront sensing AB We discuss conceptual design issues for a 1600 actuator tweeter mirror/multiconjugate AO upgrade to the 349 actuator Palomar Adaptive Optics System (PALAO). Based upon a 42 x 42 actuator Photonex deformable mirror technology, developed by Xinetics, Inc., this upgrade would enable unique science at visible wavelengths and deliver unprecedented near-infrared Strehl ratios for modestly bright (mV = 9) guide stars. When used in conjunction with the existing 349 actuator Xinetics, Inc. deformable mirror, a series of pressing issues regarding the practical utility of multiconjugate adaptive correction for extremely large telescopes could be addressed. By utilizing a low noise (EEV39) wavefront sensor camera developed by SciMeasure Analytical Systems, Inc., this system would provide on-axis K-band Strehl ratio of >95%, improving scientific throughput and enabling the detection and spectroscopy of unresolved companions in an unprecedented contrast space around nearby stars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dekany, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 6 Z9 6 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3632-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4007 BP 175 EP 179 DI 10.1117/12.390293 PN 1&2 PG 5 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BQ70C UT WOS:000089218600020 ER PT S AU O'Connor, DJ Graves, JE Northcott, M Toomey, D Joseph, R Shelton, C AF O'Connor, DJ Graves, JE Northcott, M Toomey, D Joseph, R Shelton, C BE Wizinowich, PL TI Curvature-based adaptive optics for the NASA-IRTF SO ADAPTIVE OPTICAL SYSTEMS TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical Systems Technology CY MAR 29-31, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc ID UNIVERSITY-OF-HAWAII AB The IRTF is a 3.0 meter, f/38, infrared optimized, cassegrain telescope operated under contract from NASA with the primary mission of providing ground-based support for NASA's planetary missions. We are currently in the design and construction phase of a 36 element, curvature-based, natural guide star, adaptive optics facility installation for the IRTF. System architecture will be modeled on the highly successful AO systems developed at the University of Hawaii. The system should achieve an AO efficiency, q greater than or equal to 0.4. The Strehl ratio is expected to exceed 0.8 in the K band. We estimate a limiting guide star magnitude for full correction of m(R) = 14.4. C1 NASA, IRTF, Manoa Off, Honolulu, HI 96822 USA. RP O'Connor, DJ (reprint author), NASA, IRTF, Manoa Off, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. NR 9 TC 2 Z9 2 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3632-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4007 BP 180 EP 184 DI 10.1117/12.390295 PN 1&2 PG 5 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BQ70C UT WOS:000089218600021 ER PT S AU Dekany, R Banfield, D Oppenheimer, BR Bouchez, A Brown, M Hayward, T Brandl, B Troy, M Brack, G Trinh, T Shi, F AF Dekany, R Banfield, D Oppenheimer, BR Bouchez, A Brown, M Hayward, T Brandl, B Troy, M Brack, G Trinh, T Shi, F BE Wizinowich, PL TI Solar system science with subarcsecond slit spectroscopy SO ADAPTIVE OPTICAL SYSTEMS TECHNOLOGY, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical Systems Technology CY MAR 29-31, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE adaptive optics; slit spectroscopy; Neptune; Titan ID VERTICAL DISTRIBUTIONS; SPECTROPHOTOMETRY; ATMOSPHERE; AEROSOLS; NEPTUNE; TITAN AB During its first year of shared-risk observations, the PALAO/PHARO adaptive optics system has been employed to obtain near-infrared R similar to 1000 spectra of solar system targets at spectroscopic slit widths of 0.5 and 0.1 arcsec, and corresponding spatial resolution along the slit as fine as 0.08 arcsec. Phenomena undergoing initial investigation include condensate formation in the atmospheres of Neptune, and the Saturnian moon, Titan. We present the results of this AO spectroscopy campaign and discuss AO specific considerations in the reduction and interpretation of this data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dekany, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3632-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4007 BP 811 EP 815 DI 10.1117/12.390309 PN 1&2 PG 5 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BQ70C UT WOS:000089218600089 ER PT S AU Egoavil, M Puster, R AF Egoavil, M Puster, R BE Sunden, B Brebbia, CA TI A severe buoyancy problem analysis and solution using CFD SO ADVANCED COMPUTATIONAL METHODS IN HEAT TRANSFER VI SE COMPUTATIONAL STUDIES LA English DT Proceedings Paper CT 6th International Conference on Advanced Computational Methods in Heat Transfer CY JUN 26-28, 2000 CL MADRID, SPAIN SP Wessex Inst Technol, Dev Heat Transfer Book Series AB The 8-Foot High-Temperature Tunnel (8-FT HTT) at the NASA Langley Research Center is a unique world class facility with a wide range of working parameters. New airfoil-shaped fuel injectors and an ignitor are being designed to minimize the effects of the buoyancy in the tunnel. Buoyancy in combustion chambers may seem to be a second order problem, but this is not true if large density gradients or differences are present at high pressure, as happens in the combustion chamber of the 8-FT HTT. The problem arises because not all of the enriched air at 410 degreesR to 470 degreesR is reacted and has a density that is almost 9 times that of the reaction products. The cold, dense surrounding fluid falls to the bottom of the chamber while the hot, low density reaction products tend to segregate to the top of the chamber, resulting in overheating of the liner wall at the top. Fortunately, the problem is solvable with a good computational fluid dynamics (CFD) code like the FLUENT Code (from Fluent, Inc.) and the proper approach, definition, and grid. After validating the code with experimental data, parametric cases were run. A 3D plot of the temperature contours at different sections of the tunnel show how gradually the hot gases tend to rise downstream in the combustor. The temperature profile at the exit of the combustor versus the distance from the bottom for different gaps, which are inlets of cold flow at the border (gaps of 3, 1.5, and 1.0 inch), shows that the smaller the gap, the better the uniformity of the temperature profile. A 3D plot of the temperature contours at different sections of the tunnel, using the 1-inch gap, shows that the buoyancy problem has been minimized, giving uniform temperatures at the top and bottom of the tunnel. A simple solution to a severe buoyancy problem was found by using CFD backed by experimental data. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Egoavil, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU WIT PRESS PI SOUTHAMPTON PA ASHURST LODGE, SOUTHAMPTON SO40 7AA, ASHURST, ENGLAND SN 1462-6063 BN 1-85312-818-X J9 COMPUTAT STUDIES PY 2000 VL 3 BP 193 EP 202 PG 10 WC Thermodynamics; Engineering, Mechanical; Mathematics, Applied; Mechanics SC Thermodynamics; Engineering; Mathematics; Mechanics GA BR39T UT WOS:000166299500018 ER PT S AU Afzal, RS AF Afzal, RS BE Injeyan, H Keller, U Marshall, C TI Space operation of the MOLA laser SO ADVANCED SOLID STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid State Lasers CY FEB 13-16, 2000 CL DAVOS, SWITZERLAND SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc, European Phys Soc ID MARS; ALTIMETER; TOPOGRAPHY AB The MOLA laser has been in Space over 3 years and began continuous operation, collecting topographic data of Mars, over I I months ago. The in-space performance of the laser is presented. C1 NASA, GSFC, Laser Remote Sensing Branch, College Pk, MD 20740 USA. RP Afzal, RS (reprint author), NASA, GSFC, Laser Remote Sensing Branch, 5004 Coll Ave, College Pk, MD 20740 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-628-1 J9 OSA TRENDS OPT PHOTO PY 2000 VL 34 BP 66 EP 69 PG 4 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA BU18F UT WOS:000175262800016 ER PT S AU Barnes, NP Walsh, BM Reichle, DJ Hutcheson, RL Equall, RW AF Barnes, NP Walsh, BM Reichle, DJ Hutcheson, RL Equall, RW BE Injeyan, H Keller, U Marshall, C TI Normal mode and Q-Switched 0.946 mu m oscillator and amplifier with second and third harmonic generation SO ADVANCED SOLID STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid State Lasers CY FEB 13-16, 2000 CL DAVOS, SWITZERLAND SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc, European Phys Soc AB A novel, dual cavity, flashlamp pumped, Q-switched, laser produced 98 mJ at 0.946 mum. Nd:GYAG, Nd:GdxY3-xAl5O12, and Nd:YAG, Nd:Y3Al5O12, were evaluated and compared at 0.946, 1.064, and 1.338 mum. For normal mode operation at 0.946 mum, a slope efficiency of approximate to0.01 was achieved while a 0.946 mum amplifier achieved a gain of approximate to1.27. Second and third harmonic of the Q-switched, 0.946 mum laser achieved an efficiency of 0.42 and 0.31, respectively. (C) 2000 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, MS474, Hampton, VA 23681 USA. NR 2 TC 2 Z9 2 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-628-1 J9 OSA TRENDS OPT PHOTO PY 2000 VL 34 BP 131 EP 136 PG 6 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA BU18F UT WOS:000175262800028 ER PT S AU Murray, KE Barnes, NP Walsh, BM Hutcheson, RL Kokta, MR AF Murray, KE Barnes, NP Walsh, BM Hutcheson, RL Kokta, MR BE Injeyan, H Keller, U Marshall, C TI Multiwavelength laser for medical applications and the implications of atmospheric lensing SO ADVANCED SOLID STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid State Lasers CY FEB 13-16, 2000 CL DAVOS, SWITZERLAND SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc, European Phys Soc AB Lasing at two medically important wavelengths, 2.124 mum and 2.700 mum, has been achieved from a single multiply doped laser rod in a simple resonator, Effects of atmospheric absorption and lensing were explored. (C) 2000 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Murray, KE (reprint author), NASA, Langley Res Ctr, MS474, Hampton, VA 23681 USA. NR 3 TC 6 Z9 6 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-628-1 J9 OSA TRENDS OPT PHOTO PY 2000 VL 34 BP 170 EP 173 PG 4 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA BU18F UT WOS:000175262800036 ER PT S AU Yu, JR Petros, M Singh, UN Barnes, NP AF Yu, JR Petros, M Singh, UN Barnes, NP BE Injeyan, H Keller, U Marshall, C TI An efficient end-pumped Ho : Tm : YLF disk amplifier SO ADVANCED SOLID STATE LASERS, PROCEEDINGS SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Advanced Solid State Lasers CY FEB 13-16, 2000 CL DAVOS, SWITZERLAND SP Opt Soc Amer, IEEE, Lasers & Electro Opt Soc, European Phys Soc ID LASER AB An efficient diode-pumped, room temperature Ho:Tm:YLF disk amplifier was realized by end-pump configuration, Compared to side pump configuration, about a factor three improvement in system efficiency has been demonstrated. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yu, JR (reprint author), NASA, Langley Res Ctr, MS 474, Hampton, VA 23681 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-628-1 J9 OSA TRENDS OPT PHOTO PY 2000 VL 34 BP 174 EP 177 PG 4 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA BU18F UT WOS:000175262800037 ER PT S AU Ames, T Koans, L Sall, K Warsaw, C AF Ames, T Koans, L Sall, K Warsaw, C BE Lewis, H TI Using XML and Java for telescope and instrumentation control SO ADVANCED TELESCOPE AND INSTRUMENTATION CONTROL SOFTWARE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Telescope and Instrumentation Control Software CY MAR 29-30, 2000 CL MUNICH, GERMANY SP SPIE, DFM Engn Inc, European SO Observ DE astronomy; infrared astronomy; XML; instrument : description; telescope : control; SOFIA; NASA : GSFC; software : methodology; Java AB Traditionally, instrument command and control systems have been highly specialized, consisting mostly of custom code that is difficult to develop, maintain, and extend. Such solutions are initially very costly and are inflexible to subsequent engineering change requests, increasing software maintenance costs. Instrument description is too tightly coupled with details of implementation NASA Goddard Space Flight Center and AppNet, Inc. are developing a general and highly extensible framework that applies to any kind of instrument that can be controlled by a computer. The software architecture combines the platform independent processing capabilities of Java with the power of the Extensible Markup Language (XML), a human readable and machine understandable way to describe structured data. A key aspect of the object-oriented architecture is software that is driven by an instrument description. This description is written using the Astronomical instrument Markup Language (AIML), a domain specific implementation of the more generalized Instrument Markup Language (IML). IML is used to describe graphical user interfaces to control and monitor the instrument, command sets and command formats, data streams, communication mechanisms, and data processing algorithms. The current effort is targeted for the High-resolution Airborne Wideband Camera (HAWC), a first-light instrument of the Stratospheric Observatory for Infrared Astronomy (SOFIA). A previous application of this technology was for the Spectral and Photometric imaging REceiver (SPIRE), one of the three focal plane instruments proposed for the European Space Agency's (ESA) Far Infrared Space Telescope (FIRST). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ames, T (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 14 TC 4 Z9 5 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3634-8 J9 P SOC PHOTO-OPT INS PY 2000 VL 4009 BP 2 EP 12 DI 10.1117/12.388380 PG 11 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BQ62F UT WOS:000088994500001 ER PT S AU Graybeal, J Brock, D Papke, B AF Graybeal, J Brock, D Papke, B BE Lewis, H TI The use of open source software for SOFIA's airborne data system SO ADVANCED TELESCOPE AND INSTRUMENTATION CONTROL SOFTWARE SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Advanced Telescope and Instrumentation Control Software CY MAR 29-30, 2000 CL MUNICH, GERMANY SP SPIE, DFM Engn Inc, European SO Observ DE SOFIA; data system; software; open source; development tools; MCCS AB The SOFIA data system must meet numerous technical and organizational objectives, including widely available distribution to support integration and testing at users' institutions. As with all professional data system software development, a wide range of sophisticated development tools are required. With open source software now widely available, it is possible to build an advanced Unix-based development environment taking full advantage of freely available tools. This paper analyzes advantages and disadvantages of this approach, the selection processes used, and the list of tools selected to date for the SOFIA development effort. C1 NASA, Ames Res Ctr, Sterling Software, Moffett Field, CA 94035 USA. RP Graybeal, J (reprint author), NASA, Ames Res Ctr, Sterling Software, M-S 207-1, Moffett Field, CA 94035 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3634-8 J9 P SOC PHOTO-OPT INS PY 2000 VL 4009 BP 174 EP 185 DI 10.1117/12.388387 PG 12 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BQ62F UT WOS:000088994500017 ER PT J AU Chutjian, A AF Chutjian, A TI Recent applications of gaseous discharges: Dusty plasmas and upward-directed lightning SO ADVANCES IN ATOMIC, MOLECULAR, AND OPTICAL PHYSICS, VOL 43 SE ADVANCES IN ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Review ID A-SI-H; EXCITED HYDROGEN MOLECULES; GEH4 RF DISCHARGES; GAMMA-RAY FLASHES; LOWER IONOSPHERE; RED SPRITES; SILANE PLASMAS; SOLAR-SYSTEM; BLUE JETS; ELECTROMAGNETIC PULSES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. RP Chutjian, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 111 TC 1 Z9 1 U1 1 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA SN 0065-2199 J9 ADV ATOM MOL OPT PHY PY 2000 VL 43 BP 373 EP + PG 27 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA BP49S UT WOS:000085323400011 ER PT J AU Patnaik, SN Hopkins, DA AF Patnaik, SN Hopkins, DA TI General-purpose optimization method for multidisciplinary design applications SO ADVANCES IN ENGINEERING SOFTWARE LA English DT Article DE COMETBOARDS; analyzer; optimizer; structure; aircraft; engine AB A general-purpose optimization tool for multidisciplinary applications, which in the literature is known as COMETBOARDS, is bring developed at NASA Lewis Research Center. The modular organization of COMETBOARDS includes several analyzers and state-of-the-art optimization algorithms along with their cascading strategy. The code structure allows quick integration of new analyzers and optimizers. The COMETBOARDS code reads input information from a number of data files, formulates a design as a set of multidisciplinary nonlinear programming problems, and then solves the resulting problems. COMETBOARDS can be used to solve a large problem, which can be defined through multiple disciplines, each of which can be further broken down into several subproblems. Alternatively, a small portion of a large problem can be optimized in an effort to improve an existing system. Some of the other unique features of COMETBOARDS include design variable formulation, constraint formulation, subproblem coupling strategy, global scaling technique, analysis approximation, use of either sequential or parallel computational modes, and so forth. The special features and unique strengths of COMETBOARDS assist convergence and reduce the amount of CPU time used to solve the difficult optimization problems of aerospace industries. COMETBOARDS has been successfully used to solve a number of problems, including structural design of space station components, design of nozzle components of an air-breathing engine, configuration design of subsonic and supersonic aircraft, mixed flow turbofan engines, wave rotor topped engines, and so forth. This paper introduces the COMETBOARDS design tool and its versatility, which is illustrated by citing examples from structures, aircraft design, and air-breathing propulsion engine design. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Patnaik, SN (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 8 TC 6 Z9 7 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0965-9978 J9 ADV ENG SOFTW JI Adv. Eng. Softw. PD JAN PY 2000 VL 31 IS 1 BP 57 EP 63 DI 10.1016/S0965-9978(99)00033-2 PG 7 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Engineering, Multidisciplinary SC Computer Science; Engineering GA 275KT UT WOS:000084819900006 ER PT S AU Mjolsness, E Mann, T Castano, R Wold, B AF Mjolsness, E Mann, T Castano, R Wold, B BE Solla, SA Leen, TK Muller, KR TI From coexpression to coregulation: An approach to inferring transcriptional regulation among gene classes from large-scale expression data SO ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS 12 SE ADVANCES IN NEURAL INFORMATION PROCESSING SYSTEMS LA English DT Proceedings Paper CT 13th Annual Conference on Neural Information Processing Systems (NIPS) CY NOV 29-DEC 04, 1999 CL CO ID MODEL AB We provide preliminary evidence that existing algorithms for inferring small-scale gene regulation networks from gene expression data can be adapted to large-scale gene expression data coming from hybridization microarrays. The essential steps are (1) clustering many genes by their expression time-course data into a minimal set of clusters of co-expressed genes, (2) theoretically modeling the various conditions under which the time-courses are measured using a continious-time analog recurrent neural network for the cluster mean time-courses, (3) fitting such a regulatory model to the cluster mean time courses by simulated annealing with weight decay, and (4) analysing several such fits for commonalities in the circuit parameter sets including the connection matrices. This procedure can be used to assess the adequacy of existing and future gene expression time-course data sets for determining transcriptional regulatory relationships such as coregulation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mjolsness, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 21 Z9 22 U1 0 U2 1 PU M I T PRESS PI CAMBRIDGE PA FIVE CAMBRIDGE CENTER, CAMBRIDGE, MA 02142 USA SN 1049-5258 BN 0-262-19450-3 J9 ADV NEUR IN PY 2000 VL 12 BP 928 EP 934 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ93F UT WOS:000165048700131 ER PT J AU Myers, MF Rogers, DJ Cox, J Flahault, A Hay, SI AF Myers, MF Rogers, DJ Cox, J Flahault, A Hay, SI TI Forecasting disease risk for increased epidemic preparedness in public health SO ADVANCES IN PARASITOLOGY, VOL 47 SE ADVANCES IN PARASITOLOGY LA English DT Review ID NINO-SOUTHERN OSCILLATION; VECTOR-BORNE DISEASE; INFLUENZA SURVEILLANCE; EL-NINO; COMMUNICABLE DISEASES; SATELLITE DATA; UNITED-STATES; MALARIA; AFRICA; SYSTEM C1 NASA, Goddard Space Flight Ctr, Human Hlth Initiat, Greenbelt, MD 20771 USA. Univ Oxford, Dept Zool, Trypanosomiasis & Land Use Africa TALA Res Grp, Oxford OX1 3PS, England. Univ London London Sch Hyg & Trop Med, Dept Infect & Trop Dis, London WC1E 7HT, England. Fac Med St Antoine, U444, WHO Collaborating Ctr Elect Dis Surveillance, INSERM, F-75571 Paris 12, France. RP Myers, MF (reprint author), NASA, Goddard Space Flight Ctr, Human Hlth Initiat, Code 902,Bldg 32-S130E, Greenbelt, MD 20771 USA. RI Hay, Simon/F-8967-2015 OI Hay, Simon/0000-0002-0611-7272 FU Wellcome Trust [056642] NR 76 TC 33 Z9 36 U1 3 U2 4 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL ROAD, LONDON, ENGLAND NW1 7DX SN 0065-308X J9 ADV PARASIT JI Adv.Parasitol. PY 2000 VL 47 BP 309 EP 330 PG 22 WC Parasitology SC Parasitology GA BQ96T UT WOS:000165166800009 PM 10997211 ER PT J AU Wood, BL Beck, LR Lobitz, BM Bobo, MR AF Wood, BL Beck, LR Lobitz, BM Bobo, MR TI Education, outreach and the future of remote sensing in human health SO ADVANCES IN PARASITOLOGY, VOL 47 SE ADVANCES IN PARASITOLOGY LA English DT Review ID PUBLIC-HEALTH; DISEASE; VECTORS; IMAGERY C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Ames Res Ctr, NASA, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Johnson Controls World Serv, Moffett Field, CA 94035 USA. RP Wood, BL (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 18 TC 5 Z9 5 U1 1 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL ROAD, LONDON, ENGLAND NW1 7DX SN 0065-308X J9 ADV PARASIT JI Adv.Parasitol. PY 2000 VL 47 BP 331 EP 344 PG 22 WC Parasitology SC Parasitology GA BQ96T UT WOS:000165166800010 PM 10997212 ER PT S AU Lehmacher, GA Oberheide, J Schmidlin, FJ Offermann, D AF Lehmacher, GA Oberheide, J Schmidlin, FJ Offermann, D BE Rees, D TI Zero miss time and zero miss distance experiments for validation of CRISTA 2 temperatures SO ADVANCES IN REMOTE SENSING OF THE ATMOSPHERE FROM SPACE AND FROM THE GROUND SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT C2 3 Symposium of COSPAR Scientific Commission C held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res, Int Union Radio Sci, Int Union Geodesy & Geophys, Int Assoc Meteorol & Atmospher Sci, Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Sci Comm Solar Terr Phys ID CRYOGENIC INFRARED SPECTROMETERS; TELESCOPES AB The second mission of the limb sounding CRISTA experiment was from August 8-16, 1997 observing small scale dynamics in the middle atmosphere. During the supporting field campaign, balloon (radiosonde and ozonesonde) and rocket validation measurements (falling sphere and datasonde) from NASA/GSFC Wallops Flight Facility (WFF) were coordinated to obtain minimal miss time and miss distance with respect to the CRISTA measurements. Two new strategies were employed: (1) six validation orbits with the CRISTA tangent point oriented at the launch site; (2) twin falling sphere launches within a few minutes to obtain coincident measurements at different altitudes. The pointing maneuvers worked perfectly; the average minimal miss distance for WFF was 33 km. Based on preliminary data, a temperature inversion layer at around 70 km was observed simultaneously with two falling spheres and the closest CRISTA profile. Averaging ten comparisons, the falling sphere temperatures deviate systematically from CRISTA data, being 5 K warmer at 60 km and 8 K colder at 70 km. The result confirms earlier comparisons finding evidence for a systematic temperature bias of falling sphere data in the mesosphere. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Univ Wuppertal, Dept Phys, D-42097 Wuppertal, Germany. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Observat Sci Branch, Wallops Island, VA 23337 USA. RP Lehmacher, GA (reprint author), Western Kentucky Univ, Bowling Green, KY 42101 USA. RI Oberheide, Jens/C-6156-2011; Lehmacher, Gerald/F-2653-2013 OI Oberheide, Jens/0000-0001-6721-2540; NR 6 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 J9 ADV SPACE RES PY 2000 VL 26 IS 6 BP 965 EP 969 DI 10.1016/S0273-1177(00)00038-7 PG 5 WC Engineering, Aerospace; Remote Sensing SC Engineering; Remote Sensing GA BQ23H UT WOS:000087680500013 ER PT J AU Sobieszczanski-Sobieski, J Agte, JS Sandusky, RR AF Sobieszczanski-Sobieski, J Agte, JS Sandusky, RR TI Bilevel integrated system synthesis SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization CY SEP 02-04, 1998 CL ST LOUIS, MISSOURI SP Amer Inst Aeronaut & Astronaut, USAF, NASA, ISSMO ID SENSITIVITY DERIVATIVES; COUPLED SYSTEMS; OPTIMIZATION AB Bilevel integrated system synthesis is a method far the optimization of engineering systems by decomposition. It separates the system level optimization, having a relatively small number of design variables, from the potentially numerous subsystem optimizations that may each have a large number of local design variables, The subsystem optimizations are autonomous and may be conducted concurrently. Subsystem and system optimizations alternate, linked by sensitivity data, producing a design improvement in each iteration, Starting from a best guess initial design, the method improves that design in iterative cycles; each cycle comprises two steps. In step one, the system level variables are frozen and the improvement is achieved by separate, concurrent, and autonomous optimizations in the local variable subdomains. In step two, further improvement is sought in the space of the system level variables. Optimum sensitivity data link the second step to the first. The method prototype was implemented using MATLAB(R) and iSIGHT programming software and tested on a simplified, conceptual level supersonic business jet design, and a detailed design of an electronic device. Satisfactory convergence and favorable agreement with the benchmark results were observed. Modularity of the method is intended to fit the human organization and map well on the computing technology of concurrent processing. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. George Washington Univ, Joint Inst Advancement Flight Sci, Washington, DC 20052 USA. RP Sobieszczanski-Sobieski, J (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 29 TC 66 Z9 67 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 2000 VL 38 IS 1 BP 164 EP 172 DI 10.2514/2.937 PG 9 WC Engineering, Aerospace SC Engineering GA 274UK UT WOS:000084783300021 ER PT J AU Rai, MM Madavan, NK AF Rai, MM Madavan, NK TI Aerodynamic design using neural networks SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization CY SEP 02-04, 1998 CL ST LOUIS, MISSOURI SP Amer Inst Aeronaut & Astronaut, USAF, NASA, ISSMO AB An aerodynamic design procedure that incorporates the advantages of both traditional response surface methodology and neural networks is described. The procedure employs a strategy called parameter-based partitioning of the design space and uses a sequence of response surfaces based on both neural networks and polynomial fits to traverse the design space in search of the optimal solution. This approach results in response surfaces that have both the power of neural networks and the economy of low-order polynomials (in terms of number of simulations needed and network training requirements). Such an approach can handle design problems with many more parameters than would be possible using neural networks alone. The design procedure has been applied to the redesign of a turbine airfoil from a modern jet engine. This redesign involved the use of 15 design variables. The results obtained are closer to the target design than those obtained using an earlier method with only three design variables. The capability of the method in transforming generic shapes, such as simple curved plates, into optimal airfoils is also demonstrated. C1 NASA, Ames Res Ctr, Informat Sci & Technol Directorate, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Numer Aerosp Simulat Syst Div, Moffett Field, CA 94035 USA. RP Rai, MM (reprint author), NASA, Ames Res Ctr, Informat Sci & Technol Directorate, Moffett Field, CA 94035 USA. NR 18 TC 39 Z9 42 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD JAN PY 2000 VL 38 IS 1 BP 173 EP 182 DI 10.2514/2.938 PG 10 WC Engineering, Aerospace SC Engineering GA 274UK UT WOS:000084783300022 ER PT S AU Erickson, EF Dunham, EW AF Erickson, EF Dunham, EW BE Melugin, RK Roser, HP TI Image stability requirement for the SOFIA telescope SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE pointing stability; image quality; SOFIA AB The basis for the pointing stability requirement in the SOFIA telescope is described. Fundamentally, it is desirable to retain the diffraction-limited image quality of the telescope to the shortest wavelengths not dominated by shear-layer seeing effects or intrinsic optical quality of the telescope. Image motion will blur the images, and may cause loss of signal and increased noise in science instruments. The expected diffraction and seeing limited image quality contributions are discussed, an analysis of the effects of image motion on observations is given, and examples related to the specification and to currently predicted performance for the SOFIA telescope are presented. 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 8 TC 5 Z9 5 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 2 EP 13 DI 10.1117/12.389101 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000001 ER PT S AU Shafer, RA Moseley, SH Ade, PA Benford, DJ Bjoraker, G Dwek, E Neufeld, DA Pajot, F Phillips, TG Stacey, GJ AF Shafer, RA Moseley, SH Ade, PA Benford, DJ Bjoraker, G Dwek, E Neufeld, DA Pajot, F Phillips, TG Stacey, GJ BE Melugin, RK Roser, HP TI Submillimeter and Far-InfraRed Experiment (SAFIRE): A PI class instrument for SOFIA SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE SOFIA; bolometer; far-infrared; submillimeter; Fabry-Perot; spectrometer; SQUID; transition edge sensor AB SAFIRE is a versatile imaging Fabry-Perot spectrograph covering 145 to 655 microns, with spectral resolving powers ranging over 5-10,000. Selected as a "PI" instrument for the airborne Stratospheric Observatory for Infrared Astronomy (SOFIA), SAFIRE will apply two-dimensional pop-up bolometer arrays to provide background-limited imaging spectrometry. Superconducting transition edge bolometers and SQUID multiplexers are being developed for these detectors. SAFIRE is expected to be a "First Light" instrument, useable during the initial SOFIA operations. Although a PI instrument rather than a "Facility Class" science instrument, it will be highly integrated with the standard SOFIA planning, observation, and data analysis tools. 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. RI Benford, Dominic/D-4760-2012; Bjoraker, Gordon/D-5032-2012; Moseley, Harvey/D-5069-2012 OI Benford, Dominic/0000-0002-9884-4206; NR 10 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 98 EP 108 DI 10.1117/12.389126 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000010 ER PT S AU Haas, MR AF Haas, MR BE Melugin, RK Roser, HP TI A telescope assembly alignment simulator for SOFIA SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE airborne; alignment; infrared; instrument; simulator; SOFIA AB Access to the cavity containing the SOFIA telescope will be severely limited to maintain mirror cleanliness. This will minimize mirror emissivity and extend the time between mirror cleaning/coating cycles, but precludes full access to the telescope for alignment of science instruments. Since there will be over 20 instrument change-outs per year, they must be efficient and trouble-free if SOFIA is to achieve its anticipated flight rate. A telescope assembly alignment simulator (TAAS) is being designed and built to enable verification of most mechanical, electrical, and optical interfaces between a science instrument and the telescope system. It is anticipated that an instrument will typically spend about a week on this simulator to complete its functional check-out and prepare for integration with the SOFIA telescope. This advance work on the simulator will enable the installation of science instruments onto the observatory in less than four hours. The current TAAS design and prototyping activities are described. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Haas, MR (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 172 EP 182 DI 10.1117/12.389128 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000018 ER PT S AU Seiffert, MD Langer, WD Lord, SD Pearson, J McGrath, WR AF Seiffert, MD Langer, WD Lord, SD Pearson, J McGrath, WR BE Melugin, RK Roser, HP TI Submillimeter astronomy investigation of line spectra (SAILS) - A balloon-borne instrument SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE SAILS; interstellar medium; balloon-borne ID GALAXY AB The Submillimeter Astronomy Investigation of Line Spectra (SAILS) is a balloon-borne experiment under study for a 100 day ultra-long duration balloon mission. The experiment would survey the galactic plane with 1 are minute angular resolution and 1 km/sec velocity resolution in the important submillimeter lines of CII, NII, and OI. These tracers provide the structure and energetics of major components of the interstellar medium. This knowledge is crucial for understanding the life cycle of the Galactic gas and the processes of star formation and galactic evolution. This instrument's survey of large regions of the galactic plane complements both FIRST and SOFIA which will excel at pointed observations with higher angular resolution and broader spectral coverage. Details of the instrument design and observing strategy are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Seiffert, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 203 EP 213 DI 10.1117/12.389098 PG 11 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000021 ER PT S AU Davidson, J Harvey, P Peterson, G AF Davidson, J Harvey, P Peterson, G BE Melugin, RK Roser, HP TI Achieving the background limit on SOFIA: A stray-light issue SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE airborne telescope; SOFIA; infrared backgrounds; stray-light AB This paper will summarize the stray-light study commissioned by USRA from BRO (Breault Research Organization) to estimate the level of dynamic background that might be observable at SOFIA's focal plane. This dynamic background is due to cavity and aircraft motions with respect to the inertially fixed telescope. BRO used their ASAP program to trace rays emitted from the Earth, aircraft engines, and telescope cavity to the focal plane through reflection and scatter off a number of surfaces (including Level 500 contaminated optics). BRO's results show that dynamic infrared backgrounds cannot be ignored on SOFIA, but if care is taken in the data acquisition process used by science teams, the Static Background Limit of SOFIA can be achieved. C1 NASA, Ames Res Ctr, USRA SOFIA Off, Moffett Field, CA 94035 USA. RP Davidson, J (reprint author), NASA, Ames Res Ctr, USRA SOFIA Off, MS 144-2, Moffett Field, CA 94035 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 248 EP 256 DI 10.1117/12.389123 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000025 ER PT S AU Meyer, AW Smith, SM Koerber, CT AF Meyer, AW Smith, SM Koerber, CT BE Melugin, RK Roser, HP TI Far-infrared BRDFs and reflectance spectra of candidate SOFIA telescope, cavity and focal-plane instrument surfaces SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE SOFIA; infrared; stray light; BRDF; CFRP; reflectance; telescope; scattering; black coatings ID BLACK AB The far-infrared reflectance and scattering properties of telescope surfaces, surrounding cavity walls, and surfaces within focal-plane instruments can be significant contributors to background noise. Radiation from sources well off-axis, such as the earth, moon or aircraft engines may be multiply scattered by the cavity walls and/or surface facets of a complex telescope structure. The Non-Specular Reflectometer (NSR) at NASA Ames Research Center was reactivated and upgraded, and used to measure reflectance and Bi-directional Reflectance Distribution Functions (BRDFs) for samples of planned telescope system structural materials and associated surface treatments. Measurements were made at wavelengths from 2.2 mu m to 640 mu m, at two angles of incidence, and at scattering angles as far as 85 degrees from normal. Samples of planned telescope system materials included carbon fiber reinforced polymer (CFRP), insulating foams, and Nomex fabric. Samples of candidate surface treatments for focal-plane instruments included two commercial surface treatments, and several samples prepared in-house with black paints and other components. In general, the samples of telescope system materials appear to have acceptable far-infrared reflectance and scattering properties, even compared to surface treatments expressly developed to minimize such effects. The commercial surface treatments appear to have excellent characteristics for use in the far-infrared. Samples prepared in-house of black paints fared poorly, unless SiC grit was mixed in. The latter approached but did not equal the performance of more carefully developed infrared black paints such as Ames 24E2 and Ball Infrared Black (BIRB). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Meyer, AW (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 263 EP 274 DI 10.1117/12.389125 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000027 ER PT S AU Kunz, N AF Kunz, N BE Melugin, RK Roser, HP TI The challenges in obtaining 0.2 arc-second pointing stability for a large telescope mounted in an open port cavity on board an aircraft flying in the stratosphere. SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE SOFIA; NASA; telescope; pointing stability; astronomy; control system; airborne; aircraft AB This paper describes some of the many challenges involved in trying to obtain 0.2 arc-second (1 micro-radian) pointing stability for a large telescope mounted in an open port cavity on board an aircraft flying in the stratosphere, specifically the Stratospheric Observatory For Infrared Astronomy (SOFIA) Project. It includes an overview of the SOFIA project including the joint project arrangement between NASA and DLR, the project status, a top overview of the science objectives and the resulting requirements. The primary focus of this paper is the engineering challenges involved in achieving the pointing stability requirement. The breadth of topics covered includes the structure, the effect of damping, the actuators, the disturbances, how the aeroloads/disturbances were measured in the wind tunnel test, the control system approach (at a very top level) etc. Finally, the most recent simulation results are described and the shopping list of possible improvement upgrades is discussed. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kunz, N (reprint author), NASA, Ames Res Ctr, MS 244-30, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 289 EP 300 DI 10.1117/12.389105 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000030 ER PT S AU Adeni, K Nelbach, F AF Adeni, K Nelbach, F BE Melugin, RK Roser, HP TI SOFIA Mission Controls and Communications System development strategy SO AIRBORNE TELESCOPE SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 1st Conference on Airborne Telescope Systems CY MAR 27-28, 2000 CL MUNICH, GERMANY SP SPIE, European SO Observ, DFM Engn Inc DE SOFIA; MCCS; systems engineering; object-oriented; COTS; software process; software architecture AB The Mission Controls and Communications System provides the communications infrastructure and mission operations framework to conduct science missions aboard the Stratospheric Observatory For Infrared Astronomy. There are several key philosophies that are driving the design and development of the MCCS. The two main design philosophies are to maximize the use of proven Commercial-Off-The-Shelf technologies to ensure cost effectiveness during development and to be scaleable to accommodate the changing operational and system requirements over the Observatory's expected 20 year operational lifetime. C1 NASA, Ames Res Ctr, SOFIA Project Off, Moffett Field, CA 94035 USA. RP Adeni, K (reprint author), NASA, Ames Res Ctr, SOFIA Project Off, Moffett Field, CA 94035 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3639-9 J9 P SOC PHOTO-OPT INS PY 2000 VL 4014 BP 411 EP 424 DI 10.1117/12.389118 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics SC Engineering; Astronomy & Astrophysics GA BQ62G UT WOS:000088995000042 ER PT S AU Leviton, DB AF Leviton, DB BE Javidi, B Psaltis, D TI Image processing for new optical pattern recognition encoders SO ALGORITHMS AND SYSTEMS FOR OPTICAL INFORMATION PROCESSING IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms and Systems for Optical Information Processing IV CY AUG 01-02, 2000 CL SAN DIEGO, CA SP SPIE DE NASA absolute optical encoder; pattern recognition; image processing; algorithm AB An all new type of absolute, optical encoder with ultra-high sensitivity has been developed at NASA's Goddard Space Flight Center.(1) These position measuring encoders are unconventional in that they rely on computational pattern recognition of high speed, electronic images made of a moving, backlit scale which carries absolute position information of either linear or rotary format. The pattern recognition algorithms combine edge detection, threshold level sensing, spatial compression, and centroiding along with fault recovery through scale image defect detection. Details of the encoder scale patterns and their design rules and the image processing algorithm which gives these encoders their unique and unparalleled performance characteristics are discussed. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. NR 1 TC 10 Z9 10 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3758-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4113 BP 32 EP 40 DI 10.1117/12.405860 PG 9 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BR57Z UT WOS:000166853600004 ER PT S AU Irons, JR AF Irons, JR BE Shen, SS Descour, MR TI The present and future of the Landsat program SO ALGORITHMS FOR MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL IMAGERY VI SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI CY APR 24-26, 2000 CL ORLANDO, FL SP SPIE AB The Landsat 7 satellite system was designed to operate in a manner that will substantially advance the application of remote land observations to global change research. The Enhanced Thematic Mapper-Plus (ETM+) sensor aboard the spacecraft currently acquires multispectral digital image data of the Earth's land surfaces on a routine basis. The quality of the ETM+ data is excellent, meeting or improving upon pre-launch specifications. The data are transmitted to a globally distributed set of ground stations including the primary U.S. ground station at the U.S. Geological Survey EROS Data Center in Sioux Falls, South Dakota. The U.S. Government manages the Landsat 7 satellite system A major program objective is to create an ETM+ data archive at the EROS Data Center that provides global coverage of the Earth's continental and coastal surfaces on a seasonal basis. These data are available on a non-discriminatory basis at the incremental cost of fulfilling a user request. Once purchased from the EROS Data Center, no restrictions are placed on subsequent distribution of the data. This strategy fosters the operational applications of ETM+ data while advancing studies of the Earth as a system. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 21046 USA. RP Irons, JR (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 21046 USA. RI Irons, James/D-8535-2012 NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3675-5 J9 PROC SPIE PY 2000 VL 4049 BP 122 EP 133 DI 10.1117/12.410333 PG 12 WC Engineering, Aerospace; Mathematics, Applied; Remote Sensing; Optics SC Engineering; Mathematics; Remote Sensing; Optics GA BQ82H UT WOS:000089706600010 ER PT S AU Teillet, PM Markham, BL Barker, JL Storey, JC Irish, RR Seiferth, JC AF Teillet, PM Markham, BL Barker, JL Storey, JC Irish, RR Seiferth, JC BE Shen, SS Descour, MR TI Landsat sensor cross-calibration using nearly-coincident matching scenes SO ALGORITHMS FOR MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL IMAGERY VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI CY APR 24-26, 2000 CL ORLANDO, FL SP SPIE DE Landsat-7 ETM+; Landsat-5 TM; sensor radiometric calibration AB Early in its mission, the Landsat-7 spacecraft was temporarily placed in a "tandem" orbit very close to that of the Landsat-5 spacecraft in order to facilitate the establishment of sensor calibration continuity between the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-5 Thematic Mapper (TM) sensors. The key period for the tandem configuration was June 1-4, 1999, during which hundreds of nearly-coincident matching scenes were recorded by both the Landsat-7 ETM+ and, in cooperation with Space Imaging and international ground stations, the Landsat-5 TM as well. The paper presents a methodology for Landsat-7 ETM+ and Landsat-5 TM cross-calibration and results based on analysis of three tandem image pairs. The approach incorporates adjustments for spectral band differences between the two sensors; With the well-calibrated ETM+ as a reference, the tandem-based cross-calibrations for the three image pairs yield TM responsivities that are consistent to each other to within a few percent or better depending on the spectral band. Comparisons with independent methods and results obtained by other groups indicate that the tandem-based cross-calibration is in close agreement with the independent results in spectral bands 1-3 but compares less favourably in the other bands. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Teillet, PM (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 6 TC 4 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3675-5 J9 P SOC PHOTO-OPT INS PY 2000 VL 4049 BP 155 EP 166 DI 10.1117/12.410336 PG 12 WC Engineering, Aerospace; Mathematics, Applied; Remote Sensing; Optics SC Engineering; Mathematics; Remote Sensing; Optics GA BQ82H UT WOS:000089706600013 ER PT S AU Schweiss, RJ Daniel, NE Derrick, DK AF Schweiss, RJ Daniel, NE Derrick, DK BE Shen, SS Descour, MR TI Landsat 7 Science Data Processing: a systems overview SO ALGORITHMS FOR MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL IMAGERY VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI CY APR 24-26, 2000 CL ORLANDO, FL SP SPIE DE landsat 7; data processing; science data processing; geometric processing; radiometric processing; freeware AB The Landsat 7 Science Data Processing System, developed by NASA for the Landsat 7 Project, provides the science data handling infrastructure used at the Earth Resources Observation Systems (EROS) Data Center (EDC) Landsat Data Handling Facility (DHF) of the United States Department of Interior, United States Geological Survey (USGS) located in Sioux Falls, South Dakota. This paper presents an overview of the Landsat 7 Science Data Processing System and details of the design, architecture, concept of operation, and management aspects of systems used in the processing of the Landsat 7 Science Data. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Schweiss, RJ (reprint author), Goddard Space Flight Ctr, Code 586, Greenbelt, MD 20771 USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3675-5 J9 P SOC PHOTO-OPT INS PY 2000 VL 4049 BP 300 EP 309 DI 10.3320/1.2763644 PG 10 WC Engineering, Aerospace; Mathematics, Applied; Remote Sensing; Optics SC Engineering; Mathematics; Remote Sensing; Optics GA BQ82H UT WOS:000089706600028 ER PT S AU Irish, RR AF Irish, RR BE Shen, SS Descour, MR TI Landsat 7 automatic cloud cover assessment SO ALGORITHMS FOR MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL IMAGERY VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI CY APR 24-26, 2000 CL ORLANDO, FL SP SPIE DE landsat; ETM; clouds; classification; ACCA; algorithm AB An automatic cloud cover assessment algorithm was developed for the Landsat 7 ground system. A scene dependent approach that employs two passes through ETM+ data was developed. In pass one, the reflective and thermal properties of scene features are used to establish the presence or absence of clouds in a scene. If present, a scene-specific thermal profile for clouds is established. In pass two, a unique thermal signature for clouds is developed and used to identify the remaining clouds in a scene. The algorithm appears to be a good cloud discriminator for most areas of the Earth. Some difficulty has appeared in imagery over Antarctica, and snow at high illumination angles is occasionally mistaken for cloud. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD USA. RP Irish, RR (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD USA. NR 4 TC 83 Z9 86 U1 0 U2 6 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3675-5 J9 P SOC PHOTO-OPT INS PY 2000 VL 4049 BP 348 EP 355 DI 10.1117/12.410358 PG 8 WC Engineering, Aerospace; Mathematics, Applied; Remote Sensing; Optics SC Engineering; Mathematics; Remote Sensing; Optics GA BQ82H UT WOS:000089706600033 ER PT S AU Arvidson, T Gasch, J Goward, SN AF Arvidson, T Gasch, J Goward, SN BE Shen, SS Descour, MR TI Building a global, consistent, and meaningful Landsat 7 data archive SO ALGORITHMS FOR MULTISPECTRAL, HYPERSPECTRAL, AND ULTRASPECTRAL IMAGERY VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms for Multispectral, Hyperspectral, and Ultraspectral Imagery VI CY APR 24-26, 2000 CL ORLANDO, FL SP SPIE DE Landsat 7; mission planning; US archive; Long Term Acquisition Plan; scheduling; science requests AB The mission of Landsat 7 is to acquire and periodically refresh a global archive of sim-lit, substantially cloud-free land scenes. For the U.S. archive, Landsat 7 is acquiring every land scene at least once every year, at an average rate of 250 scenes each day or 90,000 scenes each year. This is the first time in the 25 year history of Landsat data acquisitions that there is a deliberate goal to build this archive such that any data of interest to the majority of users will already be in the archive when they go looking for it - at the right gain setting, at the right time, substantially cloud-free, and at the right frequency of acquisition. Anticipating most users' data needs is the key to achieving this lofty goal. The Long Term Acquisition Plan (LTAP) dictates the optimum acquisition refresh cycle for each scene, based on change detection and special interest inputs. The plan also specifies monthly optimum gain settings to maximize scene data return. Scheduling software automatically schedules acquisitions in accordance with this LTAP, making decisions as to acceptable cloud cover levels, urgency of acquisition, and availability of resources to fulfill the plan. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Arvidson, T (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. NR 12 TC 3 Z9 3 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3675-5 J9 P SOC PHOTO-OPT INS PY 2000 VL 4049 BP 356 EP 367 DI 10.1117/12.410359 PG 12 WC Engineering, Aerospace; Mathematics, Applied; Remote Sensing; Optics SC Engineering; Mathematics; Remote Sensing; Optics GA BQ82H UT WOS:000089706600034 ER PT S AU Troeger, LP Domack, MS Wagner, JA AF Troeger, LP Domack, MS Wagner, JA BE Starke, EA Sanders, TH Cassada, WA TI Microstructural and mechanical characterization of shear formed aluminum alloys for airframe and space applications SO ALUMINIUM ALLOYS: THEIR PHYSICAL AND MECHANICAL PROPERTIES, PTS 1-3 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Aluminium Alloys (ICAA7) CY APR 09-14, 2000 CL CHARLOTTESVILLE, VIRGINIA SP Univ Virginia, Light Met Ctr, Aluminium Assoc, NASA, Langley Res Ctr, Reynolds Met Co DE aluminium alloys; microstructure; roll forming; shear forming; texture AB Advanced manufacturing processes such as near-net-shape forming can reduce production costs and increase the reliability of launch vehicle and airframe structural components through the reduction of material scrap and part count and the minimization of joints. The current research is an investigation of the processing-microstructure-property relationship for shear formed cylinders of the Al-Cu-Li-Mg-Ag alloy 2195 for space applications and the Al-Cu-Mg-Ag alloy C415 for airframe applications. Cylinders which have undergone various amounts of shear-forming strain have been studied to assess the microstructure and mechanical properties developed during and after shear forming. C1 NASA, Langley Res Ctr, NRC, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Troeger, LP (reprint author), NASA, Langley Res Ctr, NRC, Mail Stop 188A, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-853-2 J9 MATER SCI FORUM PY 2000 VL 331-3 BP 489 EP 494 PN 1-3 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BQ58A UT WOS:000088851600066 ER PT S AU Bird, RK Dicus, DL Fridlyander, JN Sandler, VS AF Bird, RK Dicus, DL Fridlyander, JN Sandler, VS BE Starke, EA Sanders, TH Cassada, WA TI Al-Li alloy 1441 for fuselage applications SO ALUMINIUM ALLOYS: THEIR PHYSICAL AND MECHANICAL PROPERTIES, PTS 1-3 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Aluminium Alloys (ICAA7) CY APR 09-14, 2000 CL CHARLOTTESVILLE, VIRGINIA SP Univ Virginia, Light Met Ctr, Aluminium Assoc, NASA, Langley Res Ctr, Reynolds Met Co DE Al-Li; fatigue crack growth; fatigue life; fuselage pressurization fatigue; tensile properties; toughness AB A cooperative investigation was conducted to evaluate Al-Cu-Mg-Li alloy 1441 for long service life fuselage applications. Alloy 1441 is currently being used for fuselage applications on the Russian Be-103 amphibious aircraft, and is expected to be used for fuselage skin on a new Tupolev business class aircraft. Alloy 1441 is cold-rollable and has several attributes that make it attractive for fuselage skin applications. These attributes include lower density and higher specific modulus with similar strength as compared to conventional Al-Cu-Mg alloys. Cold-rolled 1441 Al-Li sheet specimens were tested at NASA Langley Research Center (LaRC) and at the All-Russia Institute of Aviation Materials (VIAM) in Russia to evaluate tensile properties, fracture toughness, impact resistance, fatigue life and fatigue crack growth rate. In addition, fuselage panels were fabricated by Tupolev Design Bureau (TDB) using 1441 skins and Al-Zn-Mg-Cu alloy stiffeners. The panels were subjected to cyclic pressurization fatigue tests at TDB and at LaRC to simulate fuselage pressurization/depressurization during aircraft service. This paper discusses the results from this investigation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. All Russian Inst Aviat Mat VIAM, RU-107005 Moscow, Russia. RP Bird, RK (reprint author), NASA, Langley Res Ctr, 2 W Reid St,Mail Stop 188A, Hampton, VA 23681 USA. NR 5 TC 7 Z9 8 U1 0 U2 2 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-853-2 J9 MATER SCI FORUM PY 2000 VL 331-3 BP 907 EP 912 PN 1-3 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BQ58A UT WOS:000088851600129 ER PT S AU Hales, SJ Hafley, RA AF Hales, SJ Hafley, RA BE Starke, EA Sanders, TH Cassada, WA TI Texture/yield strength correlations in Al-Li near-net-shape extrusions SO ALUMINIUM ALLOYS: THEIR PHYSICAL AND MECHANICAL PROPERTIES, PTS 1-3 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Aluminium Alloys (ICAA7) CY APR 09-14, 2000 CL CHARLOTTESVILLE, VIRGINIA SP Univ Virginia, Light Met Ctr, Aluminium Assoc, NASA, Langley Res Ctr, Reynolds Met Co DE Al-Li; anisotropy; crystallographic texture; mechanical properties; microstructure; modeling; near-net shape extrusions ID ANISOTROPY AB The objective of this investigation was to correlate textural characteristics with yield strength anisotropy in identical T-stiffened extruded panels manufactured from the Al-Li alloys 2195, RX818 and 2096, Two regions within the panels were examined; mid-way between the stiffeners (skin) and directly beneath the stiffeners Cease). In all three extrusions, the texture in the skin region was comparable to rolled product and that in the base region similar to axisymmetric extruded product. The results indicate that the yield strength anisotropy tended to be greater in the base than in the skin, regardless of alloy. Two variants of the Taylor model for mechanical anisotropy in f.c.c. materials were employed to study the relationship between texture and yield strength anisotropy. The first variant assumed that all grains exhibit axisymmetric strain, whereas the second variant assumed that individual grains adopt the strain state which results in the minimum yield strength for each grain. Correlation of the results showed that the second variant consistently worked better than the first variant and also provided a better correlation for the skin regions than the base regions. Discrepancies between the model predictions and the measured yield strength anisotropy are discussed in terms of the microstructural and textural variations observed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hales, SJ (reprint author), NASA, Langley Res Ctr, 2 W Reid St,Mail Stop 188A, Hampton, VA 23681 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-853-2 J9 MATER SCI FORUM PY 2000 VL 331-3 BP 1347 EP 1352 PN 1-3 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BQ58A UT WOS:000088851600201 ER PT S AU Taminger, KMB Wagner, JA Lisagor, WB AF Taminger, KMB Wagner, JA Lisagor, WB BE Starke, EA Sanders, TH Cassada, WA TI Creep strain and strain rate response of 2219 Al alloy at high stress levels SO ALUMINIUM ALLOYS: THEIR PHYSICAL AND MECHANICAL PROPERTIES, PTS 1-3 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Aluminium Alloys (ICAA7) CY APR 09-14, 2000 CL CHARLOTTESVILLE, VIRGINIA SP Univ Virginia, Light Met Ctr, Aluminium Assoc, NASA, Langley Res Ctr, Reynolds Met Co DE Al alloy 2219; creep strain; international space station; prestrain; strain rate response; time-dependent deformation AB As a result of high localized plastic deformation experienced during proof testing in an International Space Station connecting module, a study was undertaken to determine the deformation response of a 2219-T851 roll forging. After prestraining 2219-T851 Al specimens to simulate strains observed during the proof testing, creep tests were conducted in the temperature range from ambient temperature to 107 degrees C (225 degrees F) at stress levels approaching the ultimate tensile strength of 2219-T851 Al. Strain-time histories and strain rate responses were examined. The strain rate response was extremely high initially, but decayed rapidly, spanning as much as five orders of magnitude during primary creep. Select specimens were subjected to incremental step loading and exhibited initial creep rates of similar magnitude for each load step. Although the creep rates decreased quickly at all loads, the creep rates dropped faster and reached lower strain rate levels for lower applied loads. The initial creep rate and creep rate decay associated with primary creep were similar for specimens with and without prestrain; however, prestraining (strain hardening) the specimens, as in the aforementioned proof test, resulted in significantly longer creep life. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Taminger, KMB (reprint author), NASA, Langley Res Ctr, 2 W Reid St, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-853-2 J9 MATER SCI FORUM PY 2000 VL 331-3 BP 1501 EP 1506 PN 1-3 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BQ58A UT WOS:000088851600224 ER PT B AU Edberg, SJ AF Edberg, SJ BE Percy, JR Wilson, JB TI Amateur-professional cooperation: Lessons learned from the International Halley Watch 1981-1989 SO AMATEUR - PROFESSIONAL PARTNERSHIPS IN ASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Amateur - Professional Partnerships in Astronomical Research and Education CY JUL 05-07, 1999 CL UNIV TORONTO, TORONTO, CANADA SP Canadian Space Agcy, Natl Aeronaut & Spacy Agcy, Natl Sci Fdn, Univ Toronto, Off Res & Int Relat, Univ Toronto, Dept Astronomy, Univ Toronto, Dept Phys, Univ Toronto, Erindale Campus, Astron Soc Pacific, Royal Astron Soc Canada, Amer Assoc Variable Star Observers HO UNIV TORONTO C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Edberg, SJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 6 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 1-58381-052-8 J9 ASTR SOC P PY 2000 VL 220 BP 108 EP 112 PG 5 WC Astronomy & Astrophysics; Education, Scientific Disciplines SC Astronomy & Astrophysics; Education & Educational Research GA BR94B UT WOS:000168123500020 ER PT B AU Maley, PD AF Maley, PD BE Percy, JR Wilson, JB TI Partnership proposal between the amateur and professional communities in the field of earth satellite observing SO AMATEUR - PROFESSIONAL PARTNERSHIPS IN ASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Amateur - Professional Partnerships in Astronomical Research and Education CY JUL 05-07, 1999 CL UNIV TORONTO, TORONTO, CANADA SP Canadian Space Agcy, Natl Aeronaut & Spacy Agcy, Natl Sci Fdn, Univ Toronto, Off Res & Int Relat, Univ Toronto, Dept Astronomy, Univ Toronto, Dept Phys, Univ Toronto, Erindale Campus, Astron Soc Pacific, Royal Astron Soc Canada, Amer Assoc Variable Star Observers HO UNIV TORONTO C1 NASA, Johnson Space Ctr Astron Soc, Houston, TX USA. RP Maley, PD (reprint author), NASA, Johnson Space Ctr Astron Soc, Houston, TX 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 1-58381-052-8 J9 ASTR SOC P PY 2000 VL 220 BP 142 EP 145 PG 4 WC Astronomy & Astrophysics; Education, Scientific Disciplines SC Astronomy & Astrophysics; Education & Educational Research GA BR94B UT WOS:000168123500025 ER PT B AU Horack, J AF Horack, J BE Percy, JR Wilson, JB TI Gamma-ray bursters SO AMATEUR - PROFESSIONAL PARTNERSHIPS IN ASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on Amateur - Professional Partnerships in Astronomical Research and Education CY JUL 05-07, 1999 CL UNIV TORONTO, TORONTO, CANADA SP Canadian Space Agcy, Natl Aeronaut & Spacy Agcy, Natl Sci Fdn, Univ Toronto, Off Res & Int Relat, Univ Toronto, Dept Astronomy, Univ Toronto, Dept Phys, Univ Toronto, Erindale Campus, Astron Soc Pacific, Royal Astron Soc Canada, Amer Assoc Variable Star Observers HO UNIV TORONTO C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Horack, J (reprint author), NASA, George C Marshall Space Flight Ctr, 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 1-58381-052-8 J9 ASTR SOC P PY 2000 VL 220 BP 199 EP 201 PG 3 WC Astronomy & Astrophysics; Education, Scientific Disciplines SC Astronomy & Astrophysics; Education & Educational Research GA BR94B UT WOS:000168123500040 ER PT J AU Matney, ML Beck, SW Limero, TF James, JT AF Matney, ML Beck, SW Limero, TF James, JT TI Multisorbent tubes for collecting volatile organic compounds in spacecraft air SO AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL LA English DT Article DE breakthrough volume; carbosieve S-III; carbotrap; carboxen 569; Tenax-TA ID CARBON MOLECULAR-SIEVES; SOLID ADSORBENTS; TENAX-TA; POLLUTANTS; SORBENTS AB The sampling capability of Tenax-TA tubes, used in the National Aeronautics and Space Administration's solid sorbent air sampler to trap and concentrate contaminants from air aboard spacecraft, was improved by incorporating two sorbents within the tubes. Existing tubes containing only Tenax-TA allowed highly volatile compounds to "break through" during collection of a 1.5 L air sample. First the carbon molecular sieve-type sorbents Carboxen 569 and Carbosieve S-III were tested for their ability to quantitatively trap the highly volatile compounds. Breakthrough volumes were determined with the direct method, whereby low ppm levels of methanol or Freon 12 in nitrogen were flowed through the sorbent tubes at 30 ml/min, and breakthrough was detected by gas chromatography. Breakthrough volumes for methanol were about 9 L/g on Carboxen 569 and 11 L/g on Carbosieve S-III; breakthrough volumes for Freon 12 were about 7 L/g on Carboxen 559 and >26 L/g on Carbosieve S-III. Next, dual-bed tubes containing either Tenax-TA/Carbosieve S-III, Tenax-TA/Carboxen 569, or Carbotrap/Carboxen 569 to a 10-component gas mixture were exposed, in dry and in humidified air (50% relative humidity), and percentage recoveries of each compound were determined. The Tenax-TA/Carboxen 569 combination gave the best overall recoveries (75-114% for the 10 compounds). Acetaldehyde had the lowest recovery (75%) of the 10 compounds, but this value was still an improvement over either the other two sorbent combinations or the original single-sorbent tubes. C1 Wyle Labs Inc, Life Sci Syst & Serv, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Med Operat Branch, Houston, TX 77058 USA. RP Matney, ML (reprint author), Wyle Labs Inc, Life Sci Syst & Serv, 1290 Hercules Dr,Suite 120, Houston, TX 77058 USA. NR 18 TC 4 Z9 5 U1 4 U2 13 PU AMER INDUSTRIAL HYGIENE ASSOC PI FAIRFAX PA 2700 PROSPERITY AVE #250, FAIRFAX, VA 22031-4307 USA SN 0002-8894 J9 AM IND HYG ASSOC J JI Am. Ind. Hyg. Assoc. J. PD JAN-FEB PY 2000 VL 61 IS 1 BP 69 EP 75 DI 10.1202/0002-8894(2000)061<0069:MTFCVO>2.0.CO;2 PG 7 WC Environmental Sciences; Public, Environmental & Occupational Health SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health GA 292AM UT WOS:000085772000010 PM 10772617 ER PT J AU Easterling, DF Hovanitz, ES AF Easterling, DF Hovanitz, ES TI Comparison of the adsorbed mercury screening method with cold-vapor atomic absorption spectrophotometry for determination of mercury in soil SO ANALYTICAL LETTERS LA English DT Article DE mercury; cold vapor atomic absorption; mercury vapor analyzer; soil samples; gold films; Jerome gold-film detection ID GOLD AMALGAMATION; SPECTROMETRY; SORPTION AB A field screening method for the determination of elemental mercury in environmental soil samples involves the thermal desorption of the mercury from the sample onto gold and then the thermal desorption from the gold to a gold-film mercury vapor analyzer. This field screening method contains a large number of conditions that could be optimized for the various types of soils encountered. In this study, the conditions were optimized for the determination of mercury in silty clay materials, and the results were comparable to the cold-vapor atomic absorption spectrophotometric method of determination. This paper discusses the benefits and disadvantages of employing the field screening method and provides the sequence of conditions that must be optimized to employ this method of determination on other soil types. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. SAIC, Brook Pk, OH USA. RP Easterling, DF (reprint author), NASA, Glenn Res Ctr, MS 23-2 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 16 TC 4 Z9 5 U1 0 U2 1 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0003-2719 J9 ANAL LETT JI Anal. Lett. PY 2000 VL 33 IS 8 BP 1665 EP 1689 DI 10.1080/00032710008543153 PG 25 WC Chemistry, Analytical SC Chemistry GA 325NV UT WOS:000087683300019 ER PT J AU Hill, CM Street, KW Tanner, SP Philipp, WH AF Hill, CM Street, KW Tanner, SP Philipp, WH TI Preparation of ion exchange films for solid-phase spectrophotometry and solid-phase fluorometry SO ANALYTICAL LETTERS LA English DT Article DE ion exchange film; solid-phase spectrophotometry (SPS); solid-phase fluorometry (SPF) AB Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this paper we present a method for making ion exchange polymer films which considerably simplify the solid-phase spectroscopic techniques. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Goodyear Tire & Rubber Co, Topeka, KS 66601 USA. Univ W Florida, Dept Chem, Pensacola, FL 32514 USA. RP Street, KW (reprint author), NASA, Glenn Res Ctr, MS 23-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 10 Z9 11 U1 0 U2 2 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0003-2719 J9 ANAL LETT JI Anal. Lett. PY 2000 VL 33 IS 13 BP 2779 EP 2792 DI 10.1080/00032710008543222 PG 14 WC Chemistry, Analytical SC Chemistry GA 358WN UT WOS:000089580300013 ER PT S AU Bamber, JL Hardy, RJ Huybrechts, P Joughin, I AF Bamber, JL Hardy, RJ Huybrechts, P Joughin, I BE Hutter, K TI A comparison of balance velocities, measured velocities and thermomechanically modelled velocities for the Greenland ice sheet SO ANNALS OF GLACIOLOGY, VOL 30, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT XXIVth General Assembly of the European-Geophysical-Society CY APR 21-22, 1999 CL THE HAGUE, NETHERLANDS SP European Geophys Soc ID STEADY-STATE AB Balance velocities for the Greenland ice sheet have been calculated from a new digital-elevation model, accumulation-rates compilation and an existing ice-thickness grid, using a two-dimensional finite-difference scheme. The pattern of velocities over the ice sheet is presented and compared with velocities derived from synthetic-aperture-radar interferometry for part of northern Greenland and a limited number of global positioning system data. This comparison indicated that the balance-velocity scheme and boundary conditions used here provide a remarkably good representation of the dynamics of the ice sheet inland from the margins. It is suggested, therefore, that these balance-velocity data could provide a valuable method of constraining a numerical ice-sheet model. The balance velocities were compared with the diagnostic velocity field calculated from several different configurations of a numerical ice-sheet model. The general pattern of flow agrees well. The detail, however, is quite different. For example, the large (>300 km) ice stream in the northeast is not generated by the numerical model and much of the detailed flow pattern is completely lost due to the limited model resolution and limitations in the model physics. C1 Univ Bristol, Sch Geog Sci, Bristol Glaciol Ctr, Bristol BS8 1SS, Avon, England. Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bamber, JL (reprint author), Univ Bristol, Sch Geog Sci, Bristol Glaciol Ctr, Bristol BS8 1SS, Avon, England. RI Joughin, Ian/A-2998-2008; Bamber, Jonathan/C-7608-2011 OI Joughin, Ian/0000-0001-6229-679X; Bamber, Jonathan/0000-0002-2280-2819 NR 14 TC 7 Z9 8 U1 0 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-25-3 J9 ANN GLACIOL PY 2000 VL 30 BP 211 EP 216 DI 10.3189/172756400781820589 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BR18R UT WOS:000165825600029 ER PT S AU Zwally, HJ Giovinetto, MB AF Zwally, HJ Giovinetto, MB BE Steffen, K TI Spatial distribution of net surface mass balance on Greenland SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL AB The spatial distribution of surface mass balance on the Greenland ice sheet is mapped on a 50 km grid using a combination of methods depending on a zonal characterization of the diagenetic snow facies. In the zones of dry snow and upper percolation facies, the accumulation rate is calculated from microwave emissivities derived from satellite measurements using a model that is calibrated with field accumulation data. In the lower percolation zone, accumulation rates are obtained from visual interpolation of previously compiled field data, with some modification so the balance is zero at the equilibrium line. Tn the ablation zone, ablation rates are calculated as a function of ice-surface elevation and latitude. Average values of the surface balance are 263 kg m(-2)a(-1) in the m(-2)a(-1) in the ablation zone and 128 kg m(-2)a(-1) overall. accumulation zone, (-) 1259 kg m(-2)a(-1) in the Compared to the findings of a previous study using practically the same approach but different models, our bulk estimate of balance (216 Gt a(-1)) is 57% smaller, but the differences iri the estimates of net accumulation and net ablation are, respectively, 30%; and 172% larger. In this and other comparisons, there is evidence that the differences in estimates are primarily due to differences in the delineation of the equilibrium line and the estimate of ablation, and secondarily to the estimate of accumulation and interpolation of field data. The differences noted with sis other estimates reported in the last two decades are all of a size close to the composite variation of the difference (+/-50 Gt a(-1)). Our surface balance is smaller than three estimates, larger than one and in agreement with two. If substituted in the latest mass-budget estimate that indicates equilibrium, our surface balance estimate would suggest a negative budget of 55 Gt a(-1) and thus a positive contribution to sea-level change of 0.15 mm a(-1). C1 NASA, Goddard Space Flight Ctr, Raytheom ITSS, Greenbelt, MD 20771 USA. RP Zwally, HJ (reprint author), NASA, Goddard Space Flight Ctr, Raytheom ITSS, Code 971, Greenbelt, MD 20771 USA. NR 25 TC 14 Z9 14 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL PY 2000 VL 31 BP 126 EP 132 DI 10.3189/172756400781820318 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600020 ER PT S AU Joughin, IR Fahnestock, MA Bamber, JL AF Joughin, IR Fahnestock, MA Bamber, JL BE Steffen, K TI Ice flow in the northeast Greenland ice stream SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL ID SATELLITE RADAR INTERFEROMETRY; SHEET MOTION AB We have measured ice flow and detailed topography in northeastern Greenland using satellite-based synthetic-aperture radar (SXR) interferometry. The subject of this study is the large ice stream that drains this quadrant of the ice sheet. A single SAR interferogram allows the measurement of one component of motion over a several-day-long interval. We have used a set of such measurements from multiple look directions to produce a mosaic of ice-flow velocity. The resulting flow field is tied to an estimated balance-velocity distribution in slow-moving areas and assumes flow to be locally surface-parallel. The velocity field is the most detailed, consistent data-set available over a flow feature of this size. It compares with global positioning system surveyed velocity measurements at the 5 m a(-1) level. In the process of mapping ice-flow velocity an enhanced elevation model of the ice stream was produced. The elevation model is based on a blend of interferometrically measured short-wavelength topography and radar-altimetry-determined longer-wavelength topography. This enhanced model has improved information on local surface slope, which is useful for estimating the horizontal components of the velocity field. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Univ Bristol, Sch Geog Sci, Ctr Remote Sensing, Bristol BS8 1SS, Avon, England. RP Joughin, IR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Joughin, Ian/A-2998-2008; Bamber, Jonathan/C-7608-2011; Fahnestock, Mark/N-2678-2013 OI Joughin, Ian/0000-0001-6229-679X; Bamber, Jonathan/0000-0002-2280-2819; NR 16 TC 9 Z9 9 U1 0 U2 5 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL PY 2000 VL 31 BP 141 EP 146 DI 10.3189/172756400781820002 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600022 ER PT S AU Giovinetto, MB Zwally, HJ AF Giovinetto, MB Zwally, HJ BE Steffen, K TI Spatial distribution of net surface accumulation on the Antarctic ice sheet SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL ID DRONNING-MAUD-LAND; MASS-BALANCE; SNOW-ACCUMULATION; EAST ANTARCTICA; KATABATIC WINDS; CLIMATE; STREAM; PRECIPITATION; TEMPERATURE; GREENLAND AB An isopleth map showing the spatial distribution of net mass accumulation at the surface on the Antarctic ice sheet, excluding Graham Land, the Larsen Ice Shelf and eastern Palmer Land, is produced based on field data from approximately 2000 sites. A database of accumulation values for 5365 gridpoint locations with 50 km spacing is interpolated from the isopleth map, giving a bulk accumulation of 2151 Gt a(-1) and a mean of 159 kg m(-2)a(-1) for an area of 13.53 x 10(6) km(2). Following the implementation of deflation and ablation adjustments applicable to sectors of the coastal zone, the accumulation values are reduced to 2020 Gt a(-1) and 149 kg m(-2)a(-1). The new accumulation distribution is compared with another recent distribution, which was based on essentially the same field data using different analysis and interpolation criteria. Differences between the distributions are assessed using residuals for the 50 km gridpoint locations and by comparing average accumulation values for 24 drainage systems. The assessment based on residuals indicates that the two distributions show patterns of accumulation that ale coherent at the continental scale, a shared attribute underscored by a small mean residual value of 6 kg m(-2)a(-1) (a difference of <4 %). However, the regional assessment based on average accumulation values for the drainage systems shows differences that are larger than the assessment error (greater than or equal to 22 %) for six systems that collectively comprise approximately 4/10 of the ice-sheet area and 3/10 of the accumulation. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP Giovinetto, MB (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 971, Greenbelt, MD 20771 USA. NR 45 TC 86 Z9 93 U1 1 U2 7 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL PY 2000 VL 31 BP 171 EP 178 DI 10.3189/172756400781820200 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600027 ER PT S AU Hulbe, CL Joughin, IR Morse, DL Bindschadler, RA AF Hulbe, CL Joughin, IR Morse, DL Bindschadler, RA BE Steffen, K TI Tributaries to West Antarctic ice streams: characteristics deduced from numerical modelling of ice flow SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL ID SUBGLACIAL GEOLOGY; SHEETS AB A network of relatively fast-flowing tributaries in the catchment basins of the West Antarctic ice streams transport ice from the inland reservoir to the heads of the ice streams. Branches of the network follow valleys in basal topography but not all valleys contain tributaries. We investigate the circumstances Favoring tributary flow upstream of Ice Streams D and E, using a combination of observation and numerical modelling. No consistent pattern emerges. The transition from tributary to ice-stream flow occurs smoothly along the main tributary feeding into the onset of Ice Stream D, with ice thickness being relatively more important upstream, and sliding being relatively more important downstream. Elsewhere, the downstream pattern of now is more complicated, with local increases and decreases in the contribution of sliding to ice speed. Those changes may be due to variations in basal water storage, subglacial geologic properties or a combination of the two. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Texas, Inst Geophys, Austin, TX 78759 USA. RP Hulbe, CL (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Code 971, Greenbelt, MD 20771 USA. RI Joughin, Ian/A-2998-2008 OI Joughin, Ian/0000-0001-6229-679X NR 19 TC 15 Z9 15 U1 0 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL PY 2000 VL 31 BP 184 EP 190 DI 10.3189/172756400781819969 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600029 ER PT S AU Ukita, J Moritz, RE AF Ukita, J Moritz, RE BE Steffen, K TI Geometry and the deformation of pack ice: II. Simulation with a random isotropic model and implication in sea-ice rheology SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL ID DYNAMICS AB In this paper, we extend the analysis of geometry and deformation of pack ice initiated in part I by considering random isotropic geometry using the Poisson line process. The model is used to estimate opening; ridging and sliding coefficients for more realistic geometry than the idealized simple and reg;lar geometry considered in part I. We then derive the shape of yield curves by applying minimization of the maximum shear stress to a linear combination of the estimated ridging and sliding coefficients. It is found that isotropic crack geometry results in a sine-lens shape for the yield curve if sliding makes no contribution to the energy dissipation. By contrast, when sliding contributes, the shape of the yield curve becomes teardropped. These results suggest the presence of a consistent relationship between large-scale characterization of inter-flee interactions and small-scale (crack and lead) ridging processes. C1 Univ Alaska, Frontier Res Syst Global Change, Int Arctic Res Ctr, Fairbanks, AK 99775 USA. Univ Washington, Appl Phys Lab, Polar Sci Ctr, Seattle, WA 98105 USA. RP Ukita, J (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. NR 16 TC 9 Z9 9 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE, ENGLAND CB2 1ER SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL PY 2000 VL 31 BP 323 EP 326 DI 10.3189/172756400781820084 PG 4 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600051 ER PT S AU Hall, DK Tait, AB Foster, JL Chang, ATC Allen, M AF Hall, DK Tait, AB Foster, JL Chang, ATC Allen, M BE Steffen, K TI Intercomparison of satellite-derived snow-cover maps SO ANNALS OF GLACIOLOGY, VOL 31, 2000 SE Annals of Glaciology-Series LA English DT Article; Proceedings Paper CT International Symposium on the Verification of Cryospheric Models CY AUG 16-20, 1999 CL SWISS FED INST TECHNOL, ZURICH, SWITZERLAND SP Int Glaciol Soc, ETH, Univ Zurich, Schweizer Akad Nat Wissensch, Schweizer Stift Alphine Forsch HO SWISS FED INST TECHNOL ID SYSTEM; SSM/I AB In anticipation of the launch of the Earth Observing System (EOS) Terra, and the Aqua spacecraft in 1999 and 2000, respectively, efforts are ongoing to determine errors of satellite-derived snow-cover maps. EOS Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer-E (AMSR-E) snow-cover products will be produced. For this study we compare snow maps covering the same study areas in Canada and the United States, acquired from different sensors using different snow-mapping algorithms. Four locations are studied: ii) Saskatchewan, Canada; (2) New England (New Hampshire, Vermont and Massachusetts) and eastern New York; (3) central Idaho and western Montana; and (4) North and South Dakota. Snow maps were produced using a prototype MODIS snow-mapping algorithm from Landsat Thematic Mapper (TM) scenes of each study area at 30 m and when the TM data were degraded to 1 km resolution. U.S. National Operational Hydrologic Remote Sensing Center (NOHRSC) 1 km resolution snow maps were also used, as were snow maps derived from 0.5 degrees x 0.5 degrees resolution Special Sensor Microwave Imager (SSM/I) data. A land-cover map derived from the International Geosphere-Biosphere Program land-cover map of North America was also registered to the scenes. The TM, NOHRSC and SSM/I snow maps, and land-cover maps were compared digitally. In most cases, Till-derived maps show less snow cover than the NOHRSC and SSM/I maps because areas of incomplete snow cover in forests (e.g. tree canopies, branches and trunks) are seen in the TM data but not in the coarser-resolution maps which may map the areas as completely snow-covered. The snow maps generally agree with respect to the spatial variability of the snow cover. The 30 m resolution TM data provide the most accurate snow maps, and are thus used as the baseline for comparison with the other maps. Results show that the changes in amount of snow cover, as compared to to the 30 m resolution TM? maps, are lowest using the TM 1 km resolution maps, at 0-40%. The greatest change (>100%) is found in the New England study area, probably due to the presence of patchy snow cover. A scene with patchy snow cover is more difficult to map accurately than is a scene with a well-defined snowline such as is found on the Worth and South Dakota scene where the changes were 0-40 %. There are also some important differences in the amount of snow mapped using the two different SSM/I algorithms because they utilize different channels. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Natl Operat Hydrol Remote Sensing Ctr, Chanhassen, MN 55317 USA. RP Hall, DK (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974, Greenbelt, MD 20771 USA. RI Hall, Dorothy/D-5562-2012 NR 24 TC 23 Z9 23 U1 0 U2 12 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-26-1 J9 ANN GLACIOL-SER PY 2000 VL 31 BP 369 EP 376 DI 10.3189/172756400781820066 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BR60H UT WOS:000166916600059 ER PT S AU Eyman, JR Boyd, AA Jones, RB Vantine, WL Smith, S Newman, JS AF Eyman, JR Boyd, AA Jones, RB Vantine, WL Smith, S Newman, JS GP IEST TI Panel: Risk management in the new millenium SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers C1 United Space Alliance, Safety Qual & Mission Assurance, Houston, TX 77058 USA. United Space Alliance, Risk Management, Houston, TX 77058 USA. Sci Applicat Int Corp, Safety Reliabil & Qual Assurance, Houston, TX 77058 USA. NASA, Off Safety & Mission Assurance, Washington, DC 20546 USA. Fed Aviat Adm, Off Syst Safety, Washington, DC 20591 USA. Hartford Steam Boiler Inspect & Insurance Co, Engn, Hartford, CT 06102 USA. RP Eyman, JR (reprint author), United Space Alliance, Safety Qual & Mission Assurance, 1150 Gemini,USH-101A, 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 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 206 EP 209 DI 10.1109/RAMS.2000.816308 PG 4 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200034 ER PT S AU Kuo, W Carlson, CS Gregory, FD Mitrou, T Shooman, ML Vassiliades, GA AF Kuo, W Carlson, CS Gregory, FD Mitrou, T Shooman, ML Vassiliades, GA GP IEST TI Panel: Advisory board - Tools for reliability and maintainability practitioners SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers DE reliability tools; safety; risk C1 Texas A&M Univ, Zachry Engn Ctr, Dept Ind Engn, College Stn, TX 77843 USA. GM Corp, Midsize & Luxury Car Grp, Reliabil Engn, Warren, MI 48090 USA. NASA, Off Safety & Mission Assurance, Washington, DC 20546 USA. Black & Decker Inc, Towson, MD 21286 USA. CUNY Hunter Coll, Dept Comp Sci, New York, NY 10021 USA. IBM Corp, Server Grp, Business Reengn, Somers, NY 10589 USA. RP Kuo, W (reprint author), Texas A&M Univ, Zachry Engn Ctr, Dept Ind Engn, College Stn, TX 77843 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 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 260 EP 263 DI 10.1109/RAMS.2000.816318 PG 4 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200044 ER PT S AU Safie, FM Belyeu, RL AF Safie, FM Belyeu, RL GP IEST TI NASA new approach for evaluating risk reduction due to space shuttle upgrades SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers DE quantitative risk assessment; space shuttle; redesign AB As part of NASAs intensive effort to incorporate quantitative risk assessment (QRA) tools in the Agency's decision-making process concerning Space Shuttle risk, NASA has developed a powerful risk assessment tool called the Quantitative Risk Assessment System (QRAS). The QRAS is a tool designed to estimate Space Shuttle risk and evaluate Space Shuttle upgrades. This paper presents an overview of the QRAS with focus on its application for evaluating the risk reduction due to proposed Space Shuttle upgrades. The application includes a case study from the Space Shuttle main engine (SSME). The QRAS overview section of the paper includes the QRAS development process, the technical approach to model development, the QRA quantification methods and techniques, and observations concerning the complex modeling involved in QRAS. The application section of the paper describes a practical case study using QRAS models for evaluating critical Space Shuttle Program upgrades, specifically a proposed SSME nozzle upgrade. This paper presents the method for evaluating the proposed upgrade by comparing the current nozzle told design with well-established probabilistic models) to the channel wall nozzle (new design at the preliminary design level). C1 NASA, QS10, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Hernandez Engn Inc, Huntsville, AL 35812 USA. RP Safie, FM (reprint author), NASA, QS10, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 9 TC 3 Z9 3 U1 2 U2 2 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 288 EP 291 DI 10.1109/RAMS.2000.816323 PG 4 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200049 ER PT S AU Mulvihill, RJ Safie, FM AF Mulvihill, RJ Safie, FM GP IEST TI Application of the NASA risk assessment tool to the evaluation of the Space Shuttle External Tank re-welding process SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers DE probabilistic structural analysis; risk assessment; weld materials properties AB The current Space Shuttle External Tank design is called the Super Light Weight Tank (SLWT). A weight reduction of approximately 30% was achieved relative to the prior design called the Light Weight Tank (LWT). The new NASA risk assessment tool, the Quantitative Risk Assessment System (QRAS), was used to compare the risk of the two designs. The comparison includes consideration of the apparent reduction of the Design Safety Factor for SLWT welds when a weld repair is required. The risk models for the Structural Failure accident scenario include five initiating events (IEs): 1- Liquid Oxygen (LO2) Tank Component Failure, 2- Liquid Hydrogen (LH2) Tank Component Failure, 3-LO2 Tank Weld Failure, 4-LH2 Tank Weld Failure, and 5-Intertank Failure. Although the risk results for the LH2 and LO2 Tank Welds for Ifs 2 and 4 are higher for the SLWT vs. the LWT, the reverse is true for tank components IEs 1, 3 and 5. The SLWT has a slightly lower risk of Structural Failure. The impact of this difference is not significant to the total risk when the other six scenarios are also included. C1 Hernandez Engn Inc, Huntsville, AL USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Mulvihill, RJ (reprint author), 4425 San Joaquin St, Oceanside, CA 92057 USA. NR 6 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 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 364 EP 369 DI 10.1109/RAMS.2000.816335 PG 6 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200061 ER PT S AU Cornford, SL Hicks, KA AF Cornford, SL Hicks, KA GP IEST TI Evaluating the residual risks of infusing new technologies into NASA missions SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers DE NASA; New Technologies; Risk Evaluation; Defect Detection and Prevention ID HOLOGRAPHIC STORAGE; RAPID ACCESS AB NASA's need to infuse new technologies into its missions has been described. Some of the challenges associated with new technology infusion, and a way to meet those challenges, have been presented. The Technology Infusion Guideline (TIG) process has been described as well as the Defect Detection and Prevention (DDP) process that is the underlying evaluation 'engine'. An example of this evaluation on one of NASA's technologies under development has been presented. This example is used to illustrate the generic process. The results of implementing the TIG process on the example technology clearly demonstrates that the TIG process can penetrate to underlying technical details to evaluate the viability of continued technology development resources. The technology evaluated was deemed 'on the right track' and critical to NASA's future missions needs. The TIG process results in a technology infusion roadmap, or prioritized set of activities which must be performed to address the identified residual risks. These activities include alignment with other parallel technology development work, specific characterization and testing, breadboard development and miniaturization and ruggedization. The return on investment for implementing this process has been measured at over 20:1 with significant schedule savings. The risk reduction as a result of implementing this process will only be directly measurable after the technology matures to a greater extent. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cornford, SL (reprint author), CALTECH, Jet Prop Lab, MS 303-217,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 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 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 376 EP 381 DI 10.1109/RAMS.2000.816337 PG 6 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200063 ER PT S AU Cornford, SL Gibbel, M Feather, M Oberhettinger, D AF Cornford, SL Gibbel, M Feather, M Oberhettinger, D GP IEST TI A physics/engineering of failure based analysis and tool for quantifying residual risks in hardware SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM - 2000 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT Annual Reliability and Maintainability Symposium CY JAN 24-27, 2000 CL LOS ANGELES, CALIFORNIA SP IEEE, SAE, Int Soc Logist, Soc Reliabil Engineers, INst Environm Sci & Technol, IIE, Syst Safety Soc, Amer Soc Quali, Reliabil Div, Soc Reliab Engineers DE product assurance program; risk management; defect-characterization & control; physics of failure; failure detection & isolation; mission essential; test program set; test requirements; tailoring; cost effectiveness AB NASA Code Q is supporting efforts to improve the verification and validation and the risk management processes for spaceflight projects. A physics-of-failure based Defect Detection and Prevention (DDP) methodology previously developed has been integrated into a software tool and is currently being implemented on various NASA projects and as part of NASA's new model-based spacecraft development environment. The DDP methodology begins with prioritizing the risks (or FMs) relevant to a mission which need to be addressed. These risks can be reduced through the implementation of a set of detection and prevention activities-referred to herein as "PACTs (see Definitions). Each of these PACTs has some effectiveness against one or more FMs but also has an associated resource cost. The FMs can be weighted according to their likelihood of occurrence and their mission impact should they occur. The net effectiveness of various combinations of PACTs can then be evaluated against these weighted FMs to obtain the residual risk for each of these FMs and the associated resource costs to achieve these risk levels. The process thus identifies the project-relevant "tall pole" FMs and design drivers and allows real time tailoring with the evolution of the design and technology content. The DDP methodology allows risk management in its truest sense: it identifies and assesses risk, provides options and tools for risk decision making and mitigation and allows for real-time tracking of current risk status. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cornford, SL (reprint author), CALTECH, Jet Prop Lab, M-S 303-217,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Feather, Martin/A-1293-2007 NR 7 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 USA SN 0149-144X BN 0-7803-5848-1 J9 P A REL MAI PY 2000 BP 382 EP 388 DI 10.1109/RAMS.2000.816338 PG 7 WC Computer Science, Software Engineering; Engineering, Multidisciplinary; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA BR23D UT WOS:000165922200064 ER PT J AU van Paradijs, J Kouveliotou, C Wijers, RAMJ AF van Paradijs, J Kouveliotou, C Wijers, RAMJ TI Gamma-ray burst afterglows SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Review DE gamma-ray bursts; compact objects; cosmology; particle acceleration; shocks; supernovae ID HUBBLE-SPACE-TELESCOPE; FOLLOW-UP OBSERVATIONS; 14 DECEMBER 1997; INTERPLANETARY NETWORK LOCALIZATION; COUNTERPART SEARCH EXPERIMENT; COSMOLOGICAL FIREBALL MODEL; BLANDFORD-ZNAJEK MECHANISM; NEAR-INFRARED OBSERVATIONS; RELATIVISTIC BLAST WAVES; EXTERNAL SHOCK MODEL AB The discovery of counterparts in X-ray and optical to radio wavelengths has revolutionized the study of gamma -ray bursts, until recently the most enigmatic of astrophysical phenomena. We now know that gamma -ray bursts are the biggest explosions in nature, caused by the ejection of ultrarelativistic matter from a powerful energy source and its subsequent collision with its environment. We have just begun to uncover a connection between supernovae and gamma -ray bursts, and are finally constraining the properties of the ultimate source of gamma -ray burst energy. We review here the observations that have led to this breakthrough in the field; we describe the basic theory of the fireball model and discuss the theoretical understanding that has been gained from interpreting the new wealth of data on gamma -ray bursts. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Alabama, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. EM chryssa.kouveliotou@iss.msfc.nasa.gov; rwijers@astro.sunysb.edu NR 593 TC 267 Z9 268 U1 0 U2 4 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 2000 VL 38 BP 379 EP + PG 66 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385NV UT WOS:000166011300011 ER PT J AU Ehrenfreund, P Charnley, SB AF Ehrenfreund, P Charnley, SB TI Organic molecules in the interstellar medium, comets, and meteorites: A voyage from dark clouds to the early earth SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Review DE molecular clouds; solar system; carbon chemistry; origin of life; astrobiology ID POLYCYCLIC AROMATIC-HYDROCARBONS; RICH CIRCUMSTELLAR ENVELOPES; CARBON-CHAIN MOLECULES; EXTENDED RED EMISSION; STAR-FORMING REGIONS; O1 HALE-BOPP; NEUTRAL-NEUTRAL REACTIONS; ISO-SWS OBSERVATIONS; C/1996 B2 HYAKUTAKE; HYDROGENATED AMORPHOUS-CARBON AB Our understanding of the evolution of organic molecules, and their voyage from molecular clouds to the early solar system and Earth, has changed dramatically. Incorporating recent observational results from the ground and space, as well as laboratory simulation experiments and new methods for theoretical modeling, this review recapitulates the inventory and distribution of organic molecules in different environments. The evolution, survival, transport, and transformation of organics is monitored, from molecular clouds and the diffuse interstellar medium to their incorporation into solar system material such as comets and meteorites. We constrain gas phase and grain surface formation pathways to organic molecules in dense interstellar clouds, using recent observations with the Infrared Space Observatory (ISO) and ground-based radiotelescopes. The main spectroscopic evidence for carbonaceous compounds in the diffuse interstellar medium is discussed (UV bump at 2200 Angstrom, diffuse interstellar bands, extended red emission, and infrared absorption and emission bands). We critically review the signatures and unsolved problems related to the main organic components suggested to be present in the diffuse gas, such as polycyclic aromatic hydrocarbons (PAHs), fullerenes, diamonds, and carbonaceous solids. We also briefly discuss the circumstellar formation of organics around late-type stars. In the solar system, space missions to comet Halley and observations of the bright comets Hyakutake and Hale-Bopp have recently allowed a reexamination of the organic chemistry of dust and volatiles in long-period comets. We review the advances in this area and also discuss progress being made in elucidating the complex organic inventory of carbonaceous meteorites. The knowledge of organic chemistry in molecular clouds, comets, and meteorites and their common link provides constraints for the processes that lead to the origin, evolution, and distribution of life in the Galaxy. C1 Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Div Space Sci, Stanford, CA 94305 USA. RP Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, POB 9513, NL-2300 RA Leiden, Netherlands. EM pascale@strw.leidenuniv.nl; chamley@dusty.arc.nasa.gov RI Charnley, Steven/C-9538-2012 NR 490 TC 546 Z9 549 U1 24 U2 177 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 2000 VL 38 BP 427 EP + DI 10.1146/annurev.astro.38.1.427 PG 58 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 385NV UT WOS:000166011300012 ER PT J AU Burgmann, R Rosen, PA Fielding, EJ AF Burgmann, R Rosen, PA Fielding, EJ TI Synthetic aperture radar interferometry to measure Earth's surface topography and its deformation SO ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES LA English DT Review DE remote sensing; crustal deformation; earthquakes; volcanoes; land subsidence; topography ID SAN-ANDREAS FAULT; GLOBAL POSITIONING SYSTEM; LONG-VALLEY CALDERA; LANDERS EARTHQUAKE; 1992 LANDERS; CRUSTAL DEFORMATION; COSEISMIC DISPLACEMENTS; CALIFORNIA EARTHQUAKE; GALAPAGOS VOLCANOS; EUREKA VALLEY AB Synthetic aperture radar interferometry (InSAR) from Earth-orbiting spacecraft provides a new tool to map global topography and deformation of the Earth's surface. Radar images taken from slightly different viewing directions allow the construction of digital elevation models of meter-scale accuracy. These data sets aid in the analysis and interpretation of tectonic and volcanic landscapes. If the Earth's surface deformed between two radar image acquisitions, a map of the surface displacement with tens-of-meters resolution and subcentimeter accuracy can be constructed. This review gives a basic overview of InSAR for Earth scientists and presents a selection of geologic applications that demonstrate the unique capabilities of InSAR for mapping the topography and deformation of the Earth. C1 Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England. RP Burgmann, R (reprint author), Univ Calif Berkeley, Dept Geol & Geophys, 301 McCone Hall, Berkeley, CA 94720 USA. RI Fielding, Eric/A-1288-2007 OI Fielding, Eric/0000-0002-6648-8067 NR 113 TC 339 Z9 350 U1 8 U2 80 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0084-6597 J9 ANNU REV EARTH PL SC JI Annu. Rev. Earth Planet. Sci. PY 2000 VL 28 BP 169 EP 209 DI 10.1146/annurev.earth.28.1.169 PG 49 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 334HX UT WOS:000088182000008 ER PT B AU Said, MA AF Said, MA GP SPE SPE TI Biaxial test method for characterization of fabric-film laminates used in scientific balloons SO ANTEC 2000: SOCIETY OF PLASTICS ENGINEERS TECHNICAL PAPERS, CONFERENCE PROCEEDINGS, VOLS I-III LA English DT Proceedings Paper CT 58th Annual Technical Conference of the Society-of-Plastics-Engineers CY MAY 07-11, 2000 CL ORLANDO, FL SP Soc Plast Engineers AB Space Structures that require light-weight materials with sufficiently high strength and environmental endurance have been in increasing demand since the early 1980's. However, the biaxial behavior of these structural materials under pressurized loading, is rarely found in the literature. An experimental investigation was conducted to develop a test method and hardware to characterize the biaxial behavior of a fabric-film laminate intended for use as a structural envelope for large balloons. The material tested is a composite laminate of three layers. The three layers are: polyester-based woven fabric, 6 microns film of polyester (Mylar type A) and 6 microns film of linear low density polyethylene (LLDPE). The laminate structure provides high strength to weight ratio. In this study, a test technique has been developed to measure the biaxial response of the material to known stress ratios. The information gained from the test can be manipulated to estimate Poisson's ratio and the development of a material structural model. C1 NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Said, MA (reprint author), NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-855-1 PY 2000 BP 1593 EP 1596 PG 4 WC Engineering, Industrial; Polymer Science SC Engineering; Polymer Science GA BS98Q UT WOS:000171593500298 ER PT S AU Ciardo, G Luttgen, G Siminiceanu, R AF Ciardo, G Luttgen, G Siminiceanu, R BE Nielsen, M Simpson, D TI Efficient symbolic state-space construction for asynchronous systems SO APPLICATION AND THEORY OF PETRI NETS 2000, PROCEEDINGS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 21st International Conference on Application and Theory of Petri Nets (ICATPN 2000) CY JUN 26-30, 2000 CL AARHUS, DENMARK SP Univ Aarhus, CPN Grp AB Many techniques for the verification of reactive systems rely on the analysis of their reachable state spaces. In this paper, a new algorithm for the symbolic generation of the state spaces of asynchronous system models, such as Petri nets, is developed. The algorithm is based on previous work that employs Multi-valued Decision Diagrams for efficiently storing sets of reachable states. In contrast to related approaches, however, it fully exploits event locality, supports intelligent cache management, and achieves faster convergence via advanced iteration control. The algorithm is implemented in the Petri net tool SMART, and runtime results show that it often performs significantly faster than existing state-space generators. C1 Coll William & Mary, Dept Comp Sci, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. RP Coll William & Mary, Dept Comp Sci, Williamsburg, VA 23187 USA. EM ciardo@cs.wm.edu; luettgen@icase.edu; radu@cs.wm.edu NR 25 TC 30 Z9 31 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67693-7 J9 LECT NOTES COMPUT SC PY 2000 VL 1825 BP 103 EP 122 PG 20 WC Computer Science, Theory & Methods SC Computer Science GA BS97R UT WOS:000171563300008 ER PT S AU Yeh, PS Venbrux, J Bhatia, P Miller, WH AF Yeh, PS Venbrux, J Bhatia, P Miller, WH BE Tescher, AG TI A visually lossless data compression technique for real-time frame/pushbroom space science imagers SO APPLICATIONS OF DIGITAL IMAGE PROCESSING XXIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Applications of Digital Image Processing XXIII CY JUL 31-AUG 03, 2000 CL SAN DIEGO, CA SP SPIE DE coding; lossy data compression; telemetry images; space science applications; push-broom instruments AB A visually lossless data compression technique is currently being developed for space science applications under the requirement of high-speed push-broom scanning. The technique is also applicable to frame based imaging data The algorithm first performs a block transform of either a hybrid of modulated lapped transform (MLT) with discrete cosine transform (DCT), or a 2-dimensional MLT. The transform is followed by a bit-plane encoding; this results in an embedded bit string with exact desirable compression rate specified by the user. The approach requires no unique look-up table to maximize its performance and is error-resilient in that error propagation is contained within a few scan lines for push-broom applications. The compression scheme performs well on a suite of test images acquired from spacecraft instruments. Flight qualified hardware implementations are in development; a functional chip set is expected by the end of 2001. The chip set is being designed to compress data in excess of 20 Msamples/sec and support quantization from 2 to 16 bits. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yeh, PS (reprint author), NASA, Goddard Space Flight Ctr, Code 564, Greenbelt, MD 20771 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3760-3 J9 P SOC PHOTO-OPT INS PY 2000 VL 4115 BP 320 EP 331 DI 10.1117/12.411556 PG 12 WC Computer Science, Software Engineering; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BR89E UT WOS:000167921100033 ER PT S AU Campbell, RE Edwards, WC Barnes, JC Storm, ME Petway, LB Marsh, WD Chen, S AF Campbell, RE Edwards, WC Barnes, JC Storm, ME Petway, LB Marsh, WD Chen, S BE Lessard, RA Lampropoulos, GA TI Solid state UV laser development for the remote sensing of ozone from space SO APPLICATIONS OF PHOTONIC TECHNOLOGY 4: CLOSING THE GAP BETWEEN THEORY, DEVELOPMENT, AND APPLICATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 4th International Conference on Applications of Photonic Technology (ICAPT 2000) CY JUN 12-16, 2000 CL QUEBEC CITY, CANADA AB Development of a UV laser transmitter capable of operating from a space platform is a critical step in enabling global earth observations of aerosols and ozone at resolutions greater than current passive instrument capabilities. Tropospheric chemistry is well recognized as the next frontier for global atmospheric measurement. Moreover, global measurement of tropospheric ozone with high vertical resolution (less than or equal to2.5 km) from space were endorsed for the EX-1 Mission by NASA's Post-2002 Mission Planning Workshop. At this workshop, held in Easton, Maryland, in August 1998, it was recognized that a space-based UV Differential Absorption Lidar (DIAL) system was necessary in order to obtain this high- resolution capability for measurements of ozone and aerosols. The results of this workshop can be found at http://www.hq.nasa.gov/office/ese/nra/RFIdodge/Panelrev.html. For the EX-1 Mission, the UV DIAL measurement would be complemented with passive measurements of ozone precursor gases and pollutant tracer species. C1 NASA, Langley Res Ctr, Laser Syst Branch, Hampton, VA 23681 USA. RP Campbell, RE (reprint author), NASA, Langley Res Ctr, Laser Syst Branch, Mail Stop 474, Hampton, VA 23681 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3730-1 J9 P SOC PHOTO-OPT INS PY 2000 VL 4087 BP 930 EP 938 DI 10.1117/12.406330 PG 9 WC Optics SC Optics GA BS15G UT WOS:000168853700127 ER PT J AU Davila, CG Chen, TK AF Davila, CG Chen, TK TI Advanced modeling strategies for the analysis of tile-reinforced composite armor SO APPLIED COMPOSITE MATERIALS LA English DT Article DE composite armor; tile-reinforced sandwich structure; finite element analysis; element layering; superelements AB A detailed investigation of the deformation mechanisms in tile-reinforced armored components was conducted to develop the most efficient modeling strategies for the structural analysis of large components of the Composite Armored Vehicle. The limitations of conventional finite elements with respect to the analysis of tile-reinforced structures were examined, and two complementary optimal modeling strategies were developed. These strategies are element layering and the use of a tile-adhesive superelement. Element layering is a technique that uses stacks of shear deformable shell elements to obtain the proper transverse shear distributions through the thickness of the laminate. The tile-adhesive superelement consists of a statically condensed substructure model designed to take advantage of periodicity in tile placement patterns to eliminate numerical redundancies in the analysis. Both approaches can be used simultaneously to create unusually efficient models that accurately predict the global response by incorporating the correct local deformation mechanisms. C1 NASA, Langley Res Ctr, Vehicle Technol Ctr, Army Res Lab, Hampton, VA 23681 USA. RI Davila, Carlos/D-8559-2011 NR 11 TC 18 Z9 18 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0929-189X J9 APPL COMPOS MATER JI Appl. Compos. Mater. PD JAN PY 2000 VL 7 IS 1 BP 51 EP 68 DI 10.1023/A:1008923521077 PG 18 WC Materials Science, Composites SC Materials Science GA 275BC UT WOS:000084798700004 ER PT J AU Lu, Y Wang, Y Yu, Q Aguirre, AA Balazs, GH Nerurkar, VR Yanagihara, R AF Lu, Y Wang, Y Yu, Q Aguirre, AA Balazs, GH Nerurkar, VR Yanagihara, R TI Detection of herpesviral sequences in tissues of green turtles with fibropapilloma by polymerase chain reaction SO ARCHIVES OF VIROLOGY LA English DT Article ID CHELONIA-MYDAS AB An alpha-herpesvirus has been associated recently with green turtle fibropapilloma (FP). To further clarify the role of this newfound green turtle herpesvirus (GTHV) in the pathogenesis of FP, various normal-appearing tissues and organs (including skin, eye, brain, heart, liver, spleen, intestine, lung, kidney, nerve, gonad, tongue, gall bladder, urinary bladder, thyroid and peripheral blood mononuclear cells (PBMC) from blood) and tumor tissues from 19 green turtles (Chelonia mydas) with FP, and tissues from three green turtles without FP, collected during 1997 to 1999 in the Hawaiian Islands, were tested for GTHV sequences by nested polymerase chain reaction (PCR), using GTHV-specific oligonuclotide primers. GTHV sequences were detected in all tumors (51/51) and most tissues (133/167) of tumored turtles. By contrast, such sequences were undetectable in tissues (0/28) of three non-tumored turtles. Analysis of GTHV sequences detected in different tissues and tumors revealed a low degree of genetic diversity (<1%). The wide distribution of this newfound herpesvirus in tumors and tissues of tumored green turtles and its absence in tissues of non-tumored turtles, argues for an etiologic role in FP. C1 Univ Hawaii Manoa, Leahi Hosp, Pacific Biomed Res Ctr, Retroviral Res Lab, Honolulu, HI 96816 USA. Tufts Sch Vet Med, Ctr Conservat Med, Wildlife Preservat Trust Int, N Grafton, MA USA. Honolulu Lab, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI USA. RP Lu, Y (reprint author), Univ Hawaii Manoa, Leahi Hosp, Pacific Biomed Res Ctr, Retroviral Res Lab, Atherton Bldg,3675 Kilauea Ave, Honolulu, HI 96816 USA. FU NCRR NIH HHS [G12RR/AI-03061] NR 27 TC 37 Z9 38 U1 0 U2 3 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0304-8608 J9 ARCH VIROL JI Arch. Virol. PY 2000 VL 145 IS 9 BP 1885 EP 1893 DI 10.1007/s007050070063 PG 9 WC Virology SC Virology GA 358XL UT WOS:000089582400010 PM 11043948 ER PT B AU Navarro, RJ Grimm, B Flippen, AA AF Navarro, RJ Grimm, B Flippen, AA GP ASQ ASQ TI NASA research complex certified to ISO 9001: Implementing a quality management system in a research environment SO ASQ'S 54TH ANNUAL QUALITY CONGRESS PROCEEDINGS LA English DT Proceedings Paper CT 54th Annual Quality Congress CY MAY 08-10, 2000 CL INDIANAPOLIS, IN SP Amer Soc Qual DE basic quality system; government; ISO 9001 AB The National Aeronautics and Space Administration (NASA) Ames Research Center is a 3,500 person federal research complex that developed and had its quality management system independently certified in order to address the mission and budget mandates of government reinvention. NASA is the world's first multisite government agency to register all of its sites to ISO 9001. Further, NASA headquarters is among the first corporate headquarters in the world to achieve ISO 9001 registration. This paper identifies the strategy, techniques, and pitfalls associated with implementing a quality management system in a world-class federal research facility. C1 NASA, Ames Res Ctr, Syst Safety & Miss Assurance Div, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC QUALITY CONTROL PI MILWAUKEE PA 611 E WISCONSIN AVENUE, MILWAUKEE, WI 53202 USA PY 2000 BP 305 EP 310 PG 6 WC Engineering, Manufacturing; Management SC Engineering; Business & Economics GA BX89F UT WOS:000186757800058 ER PT S AU Owen, TC Mahaffy, P Niemann, HB Atreya, SK Donahue, TM Bar-Nun, A de Pater, I AF Owen, TC Mahaffy, P Niemann, HB Atreya, SK Donahue, TM Bar-Nun, A de Pater, I BE Minh, YC VanDishoeck, EF TI Chemistry in the outer solar system SO ASTROCHEMISTRY: FROM MOLECULAR CLOUDS TO PLANETARY SYSTEMS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 197th Symposium of the International-Astronomical-Union CY AUG 23-27, 1999 CL SOGWIPO, SOUTH KOREA SP Int Astron Union ID PROBE MASS-SPECTROMETER; JUPITERS ATMOSPHERE; COMET HALLEY; NEBULA; ABUNDANCE; NEPTUNE; PLANETS; GRAINS; ORIGIN; ICE AB The discovery by the Galileo Probe Mass Spectrometer that argon is enriched to the same extent as carbon and sulfur on Jupiter requires a revision of models for the formation of this giant planet. Evidently the excess heavy elements were carried to Jupiter in icy planetesimals that formed at temperatures less than or equal to 30 K. This result indicates that there is no original significance in the present position of Jupiter's orbit. C1 Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Tel Aviv Univ, Dept Geophys & Planetary Sci, Ramat Aviv, Israel. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Owen, TC (reprint author), Univ Hawaii, Astron Inst, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM owen@ifa.hawaii.edu RI Mahaffy, Paul/E-4609-2012 NR 37 TC 0 Z9 0 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-034-X J9 IAU SYMP PY 2000 IS 197 BP 483 EP 490 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU35R UT WOS:000175748400042 ER PT S AU Kress, ME AF Kress, ME BE Minh, YC VanDishoeck, EF TI New developments in inner solar nebula chemistry SO ASTROCHEMISTRY: FROM MOLECULAR CLOUDS TO PLANETARY SYSTEMS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 197th Symposium of the International-Astronomical-Union CY AUG 23-27, 1999 CL SOGWIPO, SOUTH KOREA SP Int Astron Union ID PROTOPLANETARY ACCRETION DISKS; TYPE-3 ORDINARY CHONDRITES; CHEMICAL-REACTIONS; INTERPLANETARY DUST; HYDROCARBONS; ABUNDANCES; IONIZATION; EVOLUTION; MODEL; GAS AB The molecular cloud material which became the asteroids, meteorites and inner planets was extensively processed in the inner solar nebula. The chemical complexity of the most ancient meteorites attests to the highly nonequilibrium nature of the chemistry in this region, particularly regarding the volatile elements. Theoretical models describing the time evolution of the temperature and density profiles of protoplanetary accretion disks have recently become available. Such models provide a realistic framework within which to study, for instance, the effects of lightning and surface-catalyzed (gas-grain) reactions in the inner nebula. Here, we show that the latter would have been most efficient during the meteorite-forming epoch of the nebula, at the present position of the asteroid belt. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Kress, ME (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM kress@dusty.arc.nasa.gov NR 38 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-034-X J9 IAU SYMP PY 2000 IS 197 BP 537 EP 547 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU35R UT WOS:000175748400047 ER PT S AU Cesarone, RJ Hastrup, RC Bell, DJ Lyons, DT Nelson, KG AF Cesarone, RJ Hastrup, RC Bell, DJ Lyons, DT Nelson, KG BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Architectural design for a mars communications and navigation orbital infrastructure SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Mars has become the focus of an unprecedented series of missions spanning many years, involving numerous nations and evolving from robotics to humans. Operations of this exploratory fleet will require implementation of a new communications and navigation architecture, satisfying the needs of robotic landers, revers, ascent vehicles, sample canisters, balloons and airplanes, as well as eventual human explorers. NASA's Jet Propulsion Laboratory has begun development of this architecture, comprising Mars orbiting communications and navigation satellites, along with linkage to traditional Earth-based assets, such as the Deep Space Network. The total system will effectively extend Earth-based nodes to Mars, initiating an interplanetary Internet that will bring planetary exploration right into our homes. Focus is on the orbital infrastructure. The baseline architectural system design is presented, as derived from evolving mission and program requirements. Communications and navigation performance characteristics are provided. Launch, near-Earth, interplanetary and Mars orbit insertion phases are briefly treated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cesarone, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 3 EP 16 PN 1-3 PG 14 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400001 ER PT S AU Ely, TA Anderson, R Bar-Sever, YE Bell, D Guinn, J Jah, M Kallemeyn, P Levene, E Romans, L Wu, SC AF Ely, TA Anderson, R Bar-Sever, YE Bell, D Guinn, J Jah, M Kallemeyn, P Levene, E Romans, L Wu, SC BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Mars network constellation design drivers and strategies SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB NASA's Jet Propulsion Laboratory has initiated the design of a spacecraft constellation that will provide communication relay and navigation support for a variety of future Mars missions. The objective of this constellation is to provide increased data return, enable autonomous onboard navigation with reduced reliance upon Earth-based tracking data, and substantially lower the combined operations costs of anticipated missions for Mars explorations. This study presents the results of the system analysis and trade studies performed on different constellation designs. Anticipated user requirements, candidate Mars scenarios, and the desire do supply an evolving, enabling navigation/communication infrastructure for future envisioned missions have guided the constellation selection process. Navigation and communication requirements, drivers, and metrics are presented and discussed. A preliminary design is examined in detail. It is a low altitude, retrograde hybrid constellation consisting of two subconstellations. The first subconstellation provides focused coverage near the equator, and the second is at a higher inclination and provides global coverage within a finite span of time. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ely, TA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Anderson, Rodney/0000-0001-5336-2775; Jah, Moriba/0000-0003-1109-0374 NR 4 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 17 EP 31 PN 1-3 PG 15 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400002 ER PT S AU Johnston, MD Esposito, PB Alwar, V Demcak, SW Graat, EJ Burkhart, PD Portock, BM AF Johnston, MD Esposito, PB Alwar, V Demcak, SW Graat, EJ Burkhart, PD Portock, BM BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI The strategy for the second phase of aerobraking Mars Global Surveyor SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB On February 19, 1999, the Mars Global Surveyor (MGS) spacecraft was able to propulsively establish its mapping orbit. This event followed the completion of an extended orbit insertion phase that was characterized by two distinct periods of aerobraking, During the second period of aerobraking, called "Aerobraking Phase 2", the orbit period of the spacecraft was reduced from 11.6 hours to 2 hours in just over four months. This paper focuses on and describes the strategy developed for the second phase of aerobraking MGS. This description includes the baseline aerobraking flight profile and the key trajectory metrics that were monitored in order to successfully guide the spacecraft to its desired mapping orbit. Additionally, the planned aerobraking flight profile is compared to the actual aerobraking (trajectory) results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 53 EP 68 PN 1-3 PG 16 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400004 ER PT S AU Lee, W D'Amario, L Roncoli, R Smith, J AF Lee, W D'Amario, L Roncoli, R Smith, J BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Mission design for the Mars 2003/2005 Sample Return mission SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB In May 2003, a new and exciting chapter in Mars exploration will begin with a launch that will ultimately lead to the delivery of samples from the Red Planet to Earth. This proposed Mars Sample Return (MSR) project is being conducted by NASA in conjunction with the French space agency CNES, and will utilize launches in both 2003 and 2005 with an expected sample return in October 2008. The baseline mission mode selected for the MSR mission is Mars orbit rendezvous, analogous in concept to the lunar orbit rendezvous mode used for Apollo. Specifically, MSR will employ two NASA-provided landers of nearly identical design and one CNES-provided orbiter carrying a NASA payload of rendezvous sensors, orbital capture mechanisms, and Earth return capsules. The high-level concept is that the landers will launch surface samples into Mars orbit, and the orbiter will retrieve the samples in orbit and then deliver them to Earth. This paper will provide an overview of the preliminary mission design for the Mars Sample Return mission. C1 CALTECH, Jet Prop Lab, Mars Sample Return Project, Lander Off, Pasadena, CA 91109 USA. RP Lee, W (reprint author), CALTECH, Jet Prop Lab, Mars Sample Return Project, Lander Off, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 85 EP 102 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400006 ER PT S AU D'Amario, LA Bollman, WE Lee, WJ Roncoli, RB Smith, JC Bhat, RS Frauenholz, RB AF D'Amario, LA Bollman, WE Lee, WJ Roncoli, RB Smith, JC Bhat, RS Frauenholz, RB BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Mars orbit rendezvous strategy for the Mars 2003/2005 Sample Return Mission SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The baseline scenario for the Mars 2003/2005 Sample Return Mission utilizes Mars orbit rendezvous to retrieve two orbiting sample canisters containing Martian surface material. The two canisters, placed into Mars orbit by Mars ascent vehicles carried on landers launched in 2003 and 2005, will be retrieved by an orbiter launched in 2005 and returned to Earth in 2008, Rendezvous operations last for approximately one year and are divided into three phases: the preliminary (search and orbit determination) phase, the intermediate (orbit matching) phase, and the terminal (proximity operations and capture) phase. The focus of this paper is on the intermediate rendezvous phase. During intermediate rendezvous, nodal phasing orbits are used to significantly reduce the Delta V required to align the orbit planes of the orbiter and the sample canister. Preliminary analyses have shown that the total Delta V required for intermediate rendezvous (to retrieve two sample canisters) is approximately 478 m/s (99% probability). Two rendezvous test cases have been performed to validate the rendezvous strategy and associated maneuver profile and to confirm estimated Delta V requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP D'Amario, LA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 103 EP 121 PN 1-3 PG 19 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400007 ER PT S AU Lemoine, FG Rowlands, DD Smith, DE Chinn, DS Pavlis, DE Luthcke, SB Neumann, GA Zuber, MT AF Lemoine, FG Rowlands, DD Smith, DE Chinn, DS Pavlis, DE Luthcke, SB Neumann, GA Zuber, MT BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Orbit determination for Mars Global Surveyor during mapping SO ASTRODYNAMICS 1999, PTS 1-3 SE Advances in the Astronautical Sciences LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID MODEL AB The Mars Global Surveyor (MGS) spacecraft reached its designated low-altitude, and near-circular orbit about Mars after termination of aerobraking on February 4, 1999. The Mars Orbiter Laser Altimeter (MOLA) returned its first data from this low-altitude orbit on March 1, 1999, The Doppler data acquired from the Deep Space Network were used to determine the orbit of the MGS spacecraft, so that the altimeter data could be used to map the topography of Mars. A detailed nonconservative force model was implemented for MGS that included articulation of the solar arrays. The tracking data in February and March 1999 were used to improve the knowledge of the Mars geopotential by developing MGM0964C20, a solution to 70x70 in spherical harmonics, When the improved nonconservative force model and the improved Mars gravity model, MGM0964C20, are applied in the MGS orbit determination during the mapping orbit, the overlaps of adjacent arcs in March 1999 show a consistency of 0.6 m in the radial direction, and 2 meters in total position. We demonstrate that altimeter crossovers from MOLA can be used to further improve the orbit determination for these arcs resulting in an orbit overlap consistency of 0.3 meters in the radial direction and 1.7 meters in total position. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Lemoine, FG (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 926, Greenbelt, MD 20771 USA. EM flemoine@olympus.gsfc.nasa.gov RI Rowlands, David/D-2751-2012; Luthcke, Scott/D-6283-2012; Lemoine, Frank/D-1215-2013; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 33 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 435 EP 451 PN 1-3 PG 17 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400027 ER PT S AU Hack, KJ Riehl, JP AF Hack, KJ Riehl, JP BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Trajectory development and optimization of an RBCC-based launch vehicle SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The development and optimization of the trajectory for a 300-pound payload class launch vehicle using rocket based combined cycle (RBCC) engines is presented. The trajectory design and performance optimization analysis approach, assumptions, constraints, and results as well as a brief explanation of the operational characteristics of an RBCC engine is addressed. A discussion of the selection of controls, reference frames, and constraints is also included. Additionally, several assumptions made to simplify the trajectory optimization process are discussed as well as methodology for their removal. The primary figure of merit for this analysis is the amount of mass delivered to specific orbit from a fixed initial mass. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hack, KJ (reprint author), NASA, John H Glenn Res Ctr, Lewis Field,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 2 U2 3 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 729 EP 748 PN 1-3 PG 20 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400045 ER PT S AU Matousek, S AF Matousek, S BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI SpaceTime - A MIDEX proposal to test Einstein's Equivalence Principle SO ASTRODYNAMICS 1999, PTS 1-3 SE Advances in the Astronautical Sciences LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB SpaceTime is a MIDEX-class proposal. This paper describes the mission proposed for MIDEX 98. SpaceTime uses a Jupiter gravity-assist trajectory to send a spacecraft past the sun at approximately 4 solar radii, This allows for the search of a violation of Einstein's Equivalence Principle by studying the differential red-shift of 3 atomic clocks. This low-cost mission is made possible by the new application of technology (i.e., carbon-carbon heat shield) in conjunction with a simple spacecraft design utilizing a high degree of inheritance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matousek, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 264-426, Pasadena, CA 91109 USA. EM Steve.Matousek@jpl.nasa.gov NR 13 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 799 EP 817 PN 1-3 PG 19 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400049 ER PT S AU Lyons, DT AF Lyons, DT BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Aerobraking at Venus and Mars: A comparison of the Magellan and Mars global surveyor aerobraking phases SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Two interplanetary spacecraft have been successfully aerobraked from elliptical initial orbits to nearly circular find orbits. The Magellan orbit about Venus was circularized. in 1993, late in:the extended mission. The Mars Global Surveyor spacecraft achieved a circular orbit about Mars in February 1999. The aerobraking phase of the Mars Global Surveyor mission was severely complicated when one of the solar panels was damaged during initial deployment. This paper will discuss some of the similarities and differences between these two aerobraking missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lyons, DT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 25 TC 1 Z9 1 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 859 EP 877 PN 1-3 PG 19 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400053 ER PT S AU Owens, JK Vaughan, WW Niehuss, KO Minow, J AF Owens, JK Vaughan, WW Niehuss, KO Minow, J BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Atmospheric density, solar activity, and spacecraft/satellite characteristics: An integrated relationship for orbital lifetime prediction assessment SO ASTRODYNAMICS 1999, PTS 1-3 SE Advances in the Astronautical Sciences LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The ability to accurately predict a spacecraft/satellite orbital lifetime, insertion altitude, re-boost requirements, and mission performance is mainly the result of the integrated effect from knowledge of the atmospheric density, solar activity, and timeline of vehicle characteristics. Each of these elements is dependent upon a model developed to provide the inputs necessary for the use of an orbital lifetime prediction program. This paper will address relative influences of these elements with emphasis on solar activity, atmospheric density, and drag coefficient associated with the model products used to predict orbital lifetime and related spacecraft/satellite design and operational conditions. Issues associated with the potential for improvement of the lifetime prediction model input elements will be discussed with regard to their relative contributions to improving orbital lifetime and performance predictions. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Owens, JK (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1209 EP 1225 PN 1-3 PG 17 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400074 ER PT S AU Tolson, RH Keating, GM Noll, SN Baird, DT Shellenberg, TJ AF Tolson, RH Keating, GM Noll, SN Baird, DT Shellenberg, TJ BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Utilization of Mars Global Surveyor accelerometer data for atmospheric modeling SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB To provide safe aerobraking for the Mars Global Surveyor mission, accelerometer data were utilized for near real time determination of atmospheric density and scale height. These measurements, when properly calibrated, will provide the initial data base for improvement of Mars thermospheric models. Calibration methods including adjustments for thruster firings and multi-body dynamics are presented. Some unanticipated results are shown of possible atmospheric "shocks" and standing planetary waves. C1 George Washington Univ, Sch Engn & Appl Sci, JIAFS, NASA,Langley Res Ctr, Hampton, VA 23681 USA. RP Tolson, RH (reprint author), George Washington Univ, Sch Engn & Appl Sci, JIAFS, NASA,Langley Res Ctr, MS 269, Hampton, VA 23681 USA. NR 7 TC 9 Z9 9 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1329 EP 1346 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400080 ER PT S AU Ely, TA AF Ely, TA BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Impact of eccentricity on east-west stationkeeping for the GPS class of orbits SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB A strong relationship exists between eccentricity and the potential for an orbit with a mean motion commensurability to the Earth's rotation rate to be chaotic. These complex motions can significantly impact the east-west stationkeeping process for maintaining the repeating groundtrack property of a commensurate orbit. The focus of the current study is to investigate orbits with characteristics that are similar to GPS satellites except with modestly larger eccentricities. It will be shown that at eccentricities larger than similar to .01 the chaotic regions become significant, and the need arises for a robust stable stationkeeping approach. Furthermore, the investigation will develop an analytical model for eccentricity and show the factors that contribute to its growth, thus increasing the probability of encountering chaotic motion during a typical satellite lifetime. These results are applied to selected GPS orbits. It is determined that if the initial eccentricity is sufficiently large, then the traditional SK methods can destabilize and a more robust technique is required. C1 CALTECH, Jet Prop Lab, Naviagat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Ely, TA (reprint author), CALTECH, Jet Prop Lab, Naviagat & Flight Mech Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1391 EP 1408 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400083 ER PT S AU Mullins, LD Stone, RL Evans, SW AF Mullins, LD Stone, RL Evans, SW BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Mission planning for the Chandra x-ray observatory SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID SATELLITE AB The scientific purpose of the Chandra observatory is to make astronomical observations in the x-ray portion of the electromagnetic spectrum. Both high resolution spatial imaging and moderate to high resolution spectroscopy are to be performed. This paper describes the mission planning that was conducted at Marshall Space Flight Center (MSFC) to design the orbit and launch window that would permit the observatory to function properly within its constraints and resources for at least 5 years and maybe 10 years without reservicing. This mission planning also addressed the orbital transfer sequence required to take the observatory from its initial parking orbit to the final operating orbit. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Mullins, LD (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1469 EP 1497 PN 1-3 PG 29 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400088 ER PT S AU Folta, D Beckman, M Lozier, D Galal, K AF Folta, D Beckman, M Lozier, D Galal, K BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI The Lunar Prospector mission: Results of trajectory design, quasi-frozen orbits, extended mission targeting, and lunar topography and potential models SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Lunar Prospector was selected by the National Aeronautics and Space Administration (NASA) as one of the first discovery missions to conduct solar system exploration science investigations. The mission was NASA's first lunar voyage to investigate key science objectives since Apollo and was launched in January 1998, In keeping with discovery program requirements to reduce total mission cost and utilize new technology, Lunar Prospector's mission design and control focused proven trajectory analysis tools along with the latest lunar topology and gravity data available. As part of this effort, the Goddard Space Flight Center and the Ames Research Center became partners in the Lunar Prospector navigation team to provide the trajectory analysis and orbit determination support. This paper details the mission design, maneuver planning, and the orbit determination results of the Lunar Prospector nominal and extended mission, as well as the final impact scenario. It provides an understanding of the quasi-frozen orbit design of the LP mission, the optimization process of lunar orbit targets, the orbit determination process of the nominal and extended mission, the role that the selected lunar potential models play, and the extent to which mission goals were met Mapping orbit maintenance maneuver design along with results of the actual maneuvers to maintain the orbital requirements are presented. C1 NASA, Goddard Space Flight Ctr, Syst Engn Branch, Greenbelt, MD 20771 USA. RP Folta, D (reprint author), NASA, Goddard Space Flight Ctr, Syst Engn Branch, Code 571, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1505 EP 1523 PN 1-3 PG 19 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400090 ER PT S AU Williams, KE Hong, PE Han, DS AF Williams, KE Hong, PE Han, DS BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Maneuver design and calibration for the Genesis spacecraft SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Genesis is the fifth mission selected as part of NASA's Discovery Program. Genesis will collect solar wind samples for a period of approximately two years while in orbit about the Earth-Sun L1 point. This paper addresses the design of propulsive maneuvers for Genesis which achieve science objectives while minimizing cost in light of a number of spacecraft design challenges and constraints. Topics to be discussed include the spacecraft design, maneuver decomposition algorithm, as well as operational procedures and plans fcr calibrations to improve end-of-mission performance for accurate delivery and sample recovery. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, KE (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 UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1539 EP 1547 PN 1-3 PG 9 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400092 ER PT S AU Beckman, M Guzman, JJ AF Beckman, M Guzman, JJ BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Triana mission design SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID ORBITS AB Named for the sailor on Columbus' voyage who first saw the New World, Triana is a NASA mission to the vicinity of the Sun-Earth L-1 point. From L-1, Triana will have a continuous, near full disk, sunlit view of the Earth. One of the mission goals is to release the Earth images, in near real-time, over the Internet. The mission design for Triana includes design of the Lissajous orbit, design of the transfer trajectory from Earth to L1 and design of the launch and injection into the transfer orbit. The design of the nominal Lissajous and transfer trajectories incorporates dynamical systems theory and numerical techniques from both Purdue University and Goddard Space Flight Center. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Beckman, M (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 572, Greenbelt, MD 20771 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1549 EP 1568 PN 1-3 PG 20 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400093 ER PT S AU Wilson, RS Howell, KC Lo, MW AF Wilson, RS Howell, KC Lo, MW BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Optimization of insertion cost for transfer trajectories to libration point orbits SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The objective of this work is the development of efficient techniques for preliminary optimization of the cost associated with transfer trajectories to libration point orbits in the Sun-Earth-Moon four body problem; such transfers may also include lunar gravity assists. Initially, dynamical systems theory is used to determine invariant manifolds associated with the desired libration point orbit. These manifolds are employed to produce an. initial approximation to the transfer trajectory. Specific trajectory requirements such as, transfer injection constraints, inclusion of phasing loops, and targeting of a specified state on the manifold are then incorporated into the design of the transfer trajectory: A two level differential corrections process is used to produce a fully continuous trajectory that satisfies the design constraints, and includes appropriate lunar and solar gravitational models. Based on this methodology, and using the manifold structure from dynamical systems theory, a technique is presented to optimize the cost associated with insertion onto a specified libration point orbit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilson, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 4 Z9 4 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1569 EP 1586 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400094 ER PT S AU Gefert, LP Hack, KJ AF Gefert, LP Hack, KJ BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Low-thrust control law development for transfer from low earth orbits to high energy elliptical parking orbits SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The use of solar electric propulsion (SEP) to improve a spacecraft mission performance is becoming common place. Recent human Mars architecture studies have shown that a high efficiency, reusable, non-nuclear Earth departure system is possible though the combined use of solar electric and chemical propulsion. To make this concept viable the SEP vehicle must transfer systems From low earth orbit (LEO) to a high-energy elliptical parking orbit (HEEPO). A four phased analytic control law has been developed to perform a LEO-to-HEEPO transfer. Each steering phase performs a specific task required for transfer from LEO-to-HEEPO. LEO-to-HEEPO transfer performance is reported and compared. C1 NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Gefert, LP (reprint author), NASA, John H Glenn Res Ctr Lewis Field, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1695 EP 1712 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400101 ER PT S AU Markley, FL Mortari, D AF Markley, FL Mortari, D BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI How to estimate attitude from vector observations SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID SPACECRAFT ATTITUDE; ALGORITHM; MATRIX AB The most robust estimators minimizing Wahba's loss function are Davenport's q method and the Singular Value Decomposition method. The q method, which computes the optimal quaternion as the eigenvector of a symmetric 4x4 matrix with the largest eigenvalue, is somewhat faster, The fastest algorithms, the QUaternion ESTimator (QUEST) and the EStimators of the Optimal Quaternion (ESOQ and ESOQ2), are less robust since they solve the characteristic polynomial equation for the maximum eigenvalue. This is only an issue for measurements with widely differing accuracies, so these estimators are well suited to star trackers that track multiple stars with comparable accuracies. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Markley, FL (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 571, Greenbelt, MD 20771 USA. NR 34 TC 2 Z9 4 U1 1 U2 5 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 1979 EP 1996 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400117 ER PT S AU Folta, DC Gramling, CJ Long, AC Leung, DSP Belur, SV AF Folta, DC Gramling, CJ Long, AC Leung, DSP Belur, SV BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Autonomous navigation using celestial objects SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Goddard Space Flight Center Guidance, Navigation, and Control center is currently developing autonomous navigation systems for satellites in regimes in which use of the Global Positioning System (GPS) or Tracking and Data Relay Satellite System (TDRSS) is not feasible. This paper assesses the feasibility of using standard spacecraft attitude sensors and communication components to provide autonomous navigation for high-Earth orbit (HEO) and libration-point orbit (LPO) missions. Performance results are presented as a function of sensor measurement accuracy, measurement types, measurement frequency, initial state errors, and dynamic modeling errors. This analysis indicates that real-time autonomous navigation accuracies ranging from 100 meters root mean Square (RMS) for a 3-by-20-Earth-radii HEO satellite to 10 kilometers RMS for a LPO satellite are achievable using high-accuracy attitude sensor and one-way Doppler measurements. C1 NASA, Goddard Space Flight Ctr, Syst Engn Branch, Greenbelt, MD 20771 USA. RP Folta, DC (reprint author), NASA, Goddard Space Flight Ctr, Syst Engn Branch, Code 571, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2161 EP 2177 PN 1-3 PG 17 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400128 ER PT S AU Mase, RA Spencer, DA Smith, JC Braun, RD AF Mase, RA Spencer, DA Smith, JC Braun, RD BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Navigation strategy for the Mars 2001 lander mission SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Mars Surveyor 2001 project will send an orbiter, a lander, and a rover to Mars in the 2001 opportunity. The lander will demonstrate precision landing at Mars by utilizing aggressive approach navigation and hypersonic aeromaneuvering. The guided entry will result in a landed footprint that is an order of magnitude smaller than the Mars Pathfinder and Mars Polar Lander ballistic entry footprints. This paper will focus on the interplanetary navigation strategy that will decrease entry errors and reduce the size of the landed footprint. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mase, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2193 EP 2208 PN 1-3 PG 16 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400130 ER PT S AU Esposito, PB Alwar, V Burkhart, PD Demcak, SW Graat, EJ Johnston, MD Portock, BM AF Esposito, PB Alwar, V Burkhart, PD Demcak, SW Graat, EJ Johnston, MD Portock, BM BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Navigating Mars Global Surveyor through the Martian atmosphere: Aerobraking 2 SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Mars Global Surveyor spacecraft was successfully inserted into an elliptical orbit around Mars on 9/12/97 with an orbital period of 45.0 hours. After two phases of aerobraking separated by a science-phasing-orbit interval, the orbital period was reduced to 11.6 hours on 3/27/98 and to 1.97 hours on 2/4/99, Aerobraking, through an uncertain Martian atmosphere, was responsible for circularization of the MGS orbit, Its correct termination led to a sun synchronous orbit with a local mean solar time near 2:03 am at the descending equator crossing. This paper describes the second phase of aerobraking and: a) the estimation of an atmospheric density model for every drag pass or periapsis passage by analyzing doppler tracking data, b) the generation of short-term, that is over one to several orbits, accurate atmospheric density predictions, c) maintaining the spacecraft's orbit within upper and lower bounds of atmospheric density or dynamic pressure during each periapsis passage, and d) the prediction of accurate periapsis passage times (Tp) over one to fifteen orbits. Finally, we summarize the post-aerobraking maneuvers and the state of the frozen, sun-synchronous, polar, MGS mapping orbit and its evolution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Esposito, PB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2217 EP 2236 PN 1-3 PG 20 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400132 ER PT S AU Chodas, PW Yeomans, DK AF Chodas, PW Yeomans, DK BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Predicting close approaches and estimating impact probabilities for near earth objects SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Recent popular movies have raised public consciousness of the very real possibility of a comet or asteroid collision with the Earth. A news story last year further caught the public's eye when it implied that asteroid 1997 XF11 had a distinct chance of hitting the Earth in the year 2028. The possibility of impact disappeared the very next day, and the public perceived either that astronomers had made mistaken calculations, or that the pre-discovery observations found that day had been responsible for the revised prediction. In fact, the original report of the possibility of impact in 2028 was due to an incomplete analysis, The XF11 affair has demonstrated the need for clarity and precision in public communications dealing with the possibility of Earth impact, as well as the importance of peer review before public statements like these are made. Recent analysis has shown that prior to the finding of the pre-discovery observations, there was a non-negligible probability that 1997 XF11 would collide with Earth many years after 2028, Another potentially hazardous asteroid, 1999 AN(10), has made the news this year, and this time there was indeed a remote chance of collision using the full data set. Although impact was never possible during this asteroid's primary close approach in 2027, the uncertainties allowed for a remarkably close passage. Embedded within the encounter's uncertainty region were many narrow "keyholes" which could bring the asteroid back for a close approach in a later year. Three keyholes were identified which could perturb the asteroid onto trajectories that collide with the Earth in the years 2044, 2046, or 2039. At one point, the estimated impact probability for 1999 AN(10) was on the order of 1 in 500,000, larger than for any other known object, bur still significantly less than the probability of an undiscovered asteroid of equivalent size striking the Earth before 2044. Additional astrometric measurements of 1999 AN(10) later drove its impact probability down to near-zero. A side effect of the increasing discovery rate for Near Earth Objects will be a growing number of cases with at least temporarily non-negligible impact probabilities. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Chodas, PW (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2531 EP 2550 PN 1-3 PG 20 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400150 ER PT S AU Miller, JK Antreasian, PJ Gaskell, RW Giorgini, J Helfrich, CE Owen, WM Williams, BG Yeomans, DK AF Miller, JK Antreasian, PJ Gaskell, RW Giorgini, J Helfrich, CE Owen, WM Williams, BG Yeomans, DK BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Determination of Eros physical parameters for near earth asteroid rendezvous orbit phase navigation SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID FLYBY AB Navigation of the orbit phase of the Near Earth Asteroid Rendezvous (NEAR) mission will require determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of (433) Eros. Prior to launch, little was known about Eros except for its orbit and spin rate, which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole and prime meridian. The determination of the NEAR spacecraft orbit requires a high precision model of Eros' physical parameters and the ground based data provides only marginal a priori information. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. On December 23, 1998, the NEAR spacecraft flew by Eros on a high velocity trajectory that provided a brief glimpse and allowed for an improved estimate of the Dole, prime meridian and mass of Eros. Estimates of Eros' physical parameters obtained from this flyby are presented. Application of this new knowledge to simplification of Eros orbital operations and the orbit determination strategy will be discussed. C1 CALTECH, Jet Prop Lab, Navigat Syst Sect, Pasadena, CA 91109 USA. RP Miller, JK (reprint author), CALTECH, Jet Prop Lab, Navigat Syst Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2551 EP 2568 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400151 ER PT S AU Helfrich, CE Miller, JK Antreasian, PG Carranza, E Williams, BG Dunham, DW Farquhar, RW McAdams, JV AF Helfrich, CE Miller, JK Antreasian, PG Carranza, E Williams, BG Dunham, DW Farquhar, RW McAdams, JV BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Near earth asteroid rendezvous (near) revised orbit phase trajectory design SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Trajectory design of the orbit phase of the NEAR mission involves a new process that departs significantly from those procedures used for previous missions. In most cases, a precise spacecraft ephemeris is designed well in advance of arrival at the target body. For NEAR, the uncertainty in the dynamic environment around Eros does not allow the luxury of a precise spacecraft trajectory to be defined in advance. The principal cause of this uncertainty is the limited knowledge of the gravity field and rotational state of Eros. As a result, the concept for the NEAR trajectory design is to define a number of rules for satisfying spacecraft, mission, and science constraints, and then apply these rules to various assumptions for the model of Eros. Nominal, high, and low Eros mass models are used for testing the trajectory design strategy and to bracket the ranges of parameter variations that are expected upon arrival at the asteroid. The final design is completed after arrival at Eros and determination of the actual gravity field and rotational state. The application of the NEAR orbit phase trajectory design to the current best estimate of the Eros physical parameters is described in this payer. The resulting orbit is the prototype for the actual trajectory design to be performed upon arrival at Eros in February of 2000. The trajectory is described and illustrated, and some of the problems encountered in the design and their resolution are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Helfrich, CE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-150, Pasadena, CA 91109 USA. NR 7 TC 2 Z9 2 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2569 EP 2582 PN 1-3 PG 14 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400152 ER PT S AU Dunham, DW Farquhar, RW McAdams, JV Santo, AG Heyler, GA AF Dunham, DW Farquhar, RW McAdams, JV Santo, AG Heyler, GA BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Preliminary planning for near's low-altitude operations at 433 Eros SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID ASTEROID-433 EROS; SPACECRAFT; FLYBY AB NASA's Near Earth Asteroid Rendezvous (NEAR) spacecraft will be placed into orbit around asteroid 433 Eros on February 14, Valentine's Day, in the year 2000. The spacecraft will orbit Eros with increasingly lower altitudes as the one year orbit phase progresses, This paper will provide preliminary plans for mission design and navigation during the last five weeks of the orbit phase, where several close passes to the surface will be incorporated to enhance the science return. The culmination of these close passes will result in the eventual impact of the spacecraft on the surface of Eros. The possibility of hovering within 1 km from Eros' surface exists and could be incorporated into a landing design. These close flybys and landing designs incorporate the preliminary navigation information obtained during NEAR's recent flyby of Eros on December 23, 1998. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dunham, DW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-150, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2583 EP 2600 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400153 ER PT S AU Desai, PN Cheatwood, FM AF Desai, PN Cheatwood, FM BE Howell, KC Hoots, FR Kaufman, B Alfriend, KT TI Entry dispersion analysis for the Genesis sample return capsule SO ASTRODYNAMICS 1999, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA Astrodynamics Specialist Conference CY AUG 16-19, 1999 CL GIRDWOOD, AK SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB Genesis will be the first mission to return samples from beyond the Earth-Moon system. The spacecraft will be inserted into a halo orbit about the L1 (Sun-Earth) libration point where it will remain for two years collecting solar wind particles. Upon Earth return, the sample return capsule, which is passively controlled, will descend under parachute to Utah. The present study describes the analysis of the entry, descent, and landing scenario of the returning sample capsule. The robustness of the entry sequence is assessed through a Monte Carlo dispersion analysis where the impact of off-nominal conditions is ascertained. The dispersion results indicate that the capsule attitude excursions near peak heating and drogue chute deployment are within Genesis mission limits. Additionally, the size of the resulting 3-sigma landing ellipse is 47.8 km in downrange by 15.2 km in crossrange, which is within the Utah Test and Training Range boundaries. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Desai, PN (reprint author), NASA, Langley Res Ctr, Mail Code 365, Hampton, VA 23681 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-467-2 J9 ADV ASTRONAUT SCI PY 2000 VL 103 BP 2639 EP 2656 PN 1-3 PG 18 WC Engineering, Aerospace SC Engineering GA BQ63B UT WOS:000089017400156 ER PT B AU Lubelczyk, J Parra, A AF Lubelczyk, J Parra, A BE Manset, N Veillet, C Crabtree, D TI Managing the software development process SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The goal of any software development project is to produce a product that is delivered on time, within the allocated budget, and with the capabilities expected by the customer and unfortunately, this goal is rarely achieved. However, a properly managed project in a mature software engineering environment can consistently achieve this goal. In this paper we provide an introduction to three project success factors a properly managed project, a competent project manager, and a mature software engineering environment. We will also present an overview of the benefits of a mature software engineering environment based on 24 years of data from the Software Engineering Lab, and suggest some first steps that an organization can take to begin benefiting from this environment. The depth and breadth of software engineering exceeds this paper, various references are cited with a goal of raising awareness and encouraging further investigation into software engineering and project management practices. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lubelczyk, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 3 EP 11 PG 9 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000001 ER PT B AU Shaya, E Gass, J Blackwell, J Thomas, B Holmes, B Cheung, C AF Shaya, E Gass, J Blackwell, J Thomas, B Holmes, B Cheung, C BE Manset, N Veillet, C Crabtree, D TI XML at the ADC: Steps to a next generation data repository SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The staff of the Astronomical Data Center at GSFC (ADC, http://adc.gsfc.nasa.gov) is involved in a research project to define the XML format for the metadata of an astronomical repository and for large data tables. In the process, an XML tool box is being developed for importation, enhancement, and distribution of published data and their metadata documents. There is now a working draft Document Type Definition (DTD, http://messier.gsfe.nasa.gov/xml/dataset.dtd) which specifies the required elements of content and their attributes. The documentation for each data set will be viewable in several different styles via eXtensible Stylesheet Language Transformations XSLT, (http://www.w3.org/TR/xslt) scripts. The ADC is actively creating designs for the flow of data through automated pipelines from authors and journal presses into an XML archive, as well as data retrieval through the web via the XML Query Language. C1 NASA, RITSS, Washington, DC 20546 USA. RP Shaya, E (reprint author), NASA, RITSS, Washington, DC 20546 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 87 EP 90 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000017 ER PT B AU Cheung, CY Kelley, S Roussopoulos, N AF Cheung, CY Kelley, S Roussopoulos, N BE Manset, N Veillet, C Crabtree, D TI New capabilities in the Astrophysics Multispectral Archive Search Engine SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The Astrophysics Multispectral Archive Search Engine (AMASE) uses object-oriented database techniques to provide a uniform multi-mission and multi-spectral interface to search for data in the distributed archives. We describe our experience of porting AMASE from Illustra object-relational DBMS to the Informix: Universal Data Server. New capabilities and utilities have been developed, including a spatial datablade that supports Nearest Neighbor queries. C1 NASA, Goddard Space Flight Ctr, Astrophys Data Facil, Greenbelt, MD 20771 USA. RP Cheung, CY (reprint author), NASA, Goddard Space Flight Ctr, Astrophys Data Facil, Greenbelt, MD 20771 USA. NR 1 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 227 EP 230 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000048 ER PT B AU Ames, TJ Koons, LC Sall, KB Warsaw, CE AF Ames, TJ Koons, LC Sall, KB Warsaw, CE BE Manset, N Veillet, C Crabtree, D TI Using XML and Java for astronomical instrument control SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The Astronomical Instrument Markup Language is a domain-specific implementation of the more generalized Instrument Markup Language. NASA Goddard Space Flight Center and AppNet, Inc. are developing AIML to command and control astronomical instruments. Our software architecture combines the platform-independent processing capabilities of Java with the power of XML. A key aspect of the object-oriented architecture, implemented in Java, involves software that is driven by the AIML instrument description. Our techniques, initially targeted for an airborne observatory, will eventually enable astronomers around the world to easily access infrared instruments (e.g., telescopes, cameras, and spectrometers) located in various remote and inhospitable environments. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ames, TJ (reprint author), NASA, Goddard Space Flight Ctr, Code 558, Greenbelt, MD 20771 USA. NR 3 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 271 EP 274 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000057 ER PT B AU Smith, EP AF Smith, EP BE Manset, N Veillet, C Crabtree, D TI Infrared astronomy and NGST SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The Next Generation Space Telescope (NGST), scheduled for launch in 2008, will be an infrared (0.6-10+ mum) optimized 8m telescope, passively cooled to 50K, located in an orbit about the second Lagrange point (L2). NGST is a successor to the Hubble Space Telescope (HST) and will be a key part of the NASA Origins Program. Like HST, it will be a general user observatory and will be capable of studying a wide variety of phenomena. For design purposes we are using a Design Reference Mission (DRM) which contains programs investigating; the light from the first stars and galaxies to form after the Big Bang, early supernovae and the chemical enrichment of the universe, protostellar environments within our own Galaxy, faint white dwarfs in Local Group galaxies, Kuiper Belt objects (KBO's) within the Solar system to name a few. The NGST will use many advanced technologies to realize its goals. Among these are advanced software and control systems for the telescope and its instruments. I give a brief update on the state of the NGST project and projected capabilities for this observatory. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Smith, EP (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 2 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 297 EP 306 PG 10 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000063 ER PT B AU Pence, W White, RL Greenfield, P Tody, D AF Pence, W White, RL Greenfield, P Tody, D BE Manset, N Veillet, C Crabtree, D TI A FITS image compression proposal SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB We have developed a general technique for storing compressed images in FITS binary tables. The image is first divided into one or more rectangular sub-images or tiles, then each tile is compressed and the resulting byte stream is stored in a variable length row of a binary table. By dividing the image into tiles it is possible to extract and uncompress subsections of the image without the expense of uncompressing the whole image. Several commonly used algorithms for compressing the image tiles will be supported initially, and in principle, support for any other compression algorithm may be added later. We are in the process of making trial implementations of this technique within the IRAF image kernel and within the CFITSIO subroutine library for accessing FITS files. Once completed, these implementations will allow application programs to transparently read (and perhaps write) compressed images without needing any knowledge about the compression algorithm. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pence, W (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI White, Richard/A-8143-2012 NR 1 TC 12 Z9 12 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 551 EP 554 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000115 ER PT B AU Wilson, CA Harmon, BA McCollough, ML Fishman, GJ Zhang, SN Paciesas, WS AF Wilson, CA Harmon, BA McCollough, ML Fishman, GJ Zhang, SN Paciesas, WS BE Manset, N Veillet, C Crabtree, D TI The earth occultation technique with the burst and transient source experiment SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is successfully being used as an all-sky hard X-ray monitor. The experiment consists of a, set of eight uncollimated detectors sensitive to photons in the 20 keV to 2 MeV range. Since CGRO orbits the Earth at an altitude of about 450 km, about 33% of the sky, as viewed with BATSE, is covered by the Earth at any given time. The entire sky is subject to Earth occultation for some portion of CGRO's 52 day precession period. When a source sets below or rises above the Earth's limb, atmospheric attenuation produces steplike features in the BATSE data. The observed change in count rate in several energy bands provides a measurement of the source intensity and spectrum without sophisticated background models. These occultation features are used to locate and monitor astrophysical sources with BATSE when the source signal can be separated from the detector background. Examples of step searches, spectra, light curves, and transform imaging are presented. C1 NASA, MSFC, SD 50, Dept Space Sci, Huntsville, AL 35812 USA. RP NASA, MSFC, SD 50, Dept Space Sci, Huntsville, AL 35812 USA. NR 5 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 587 EP 590 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000122 ER PT B AU Grosvenor, SR Burkhardt, C Koratkar, A Fishman, M Wolf, KR Jones, JE Ruley, L AF Grosvenor, SR Burkhardt, C Koratkar, A Fishman, M Wolf, KR Jones, JE Ruley, L BE Manset, N Veillet, C Crabtree, D TI The scientist's expert assistant demonstration SO ASTRONOMICAL DATA ANALYSIS SOFTWARE AND SYSTEMS IX SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 9th Annual Conference for Astronomical Data Analysis Software and Systems (ADASS 99) CY OCT 03-06, 1999 CL HI SP Canada France Hawaii Telescope Corp AB The Scientist's Expert Assistant (SEA) is a prototype effort for the Next Generation Space Telescope that uses a combination of artificial intelligence and user interface techniques to explore ways to substantially reduce the time and effort involved in proposal preparation for both scientists and the telescope operations staff. The Advanced Architectures and Automation Branch of NASA's Goddard Space Flight Center has been working with the Space Telescope Science Institute (STScI) to explore SEA alternatives. At ADASS '99 we were demonstrating the latest version of the SEA software. This article summarizes the new features and lessons learned in the SEA project over the last year. C1 NASA, Goddard Space Flight Ctr, Booz Allen & Hamilton, Greenbelt, MD 20771 USA. RP Grosvenor, SR (reprint author), NASA, Goddard Space Flight Ctr, Booz Allen & Hamilton, Code 588,Bld 23,Rm W409, Greenbelt, MD 20771 USA. NR 1 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 1-58381-047-1 J9 ASTR SOC P PY 2000 VL 216 BP 695 EP 698 PG 4 WC Astronomy & Astrophysics; Computer Science, Software Engineering; Instruments & Instrumentation SC Astronomy & Astrophysics; Computer Science; Instruments & Instrumentation GA BR86E UT WOS:000167857000150 ER PT J AU Borgani, S da Costa, LN Zehavi, I Giovanelli, R Haynes, AP Freudling, W Wegner, G Salzer, JJ AF Borgani, S da Costa, LN Zehavi, I Giovanelli, R Haynes, AP Freudling, W Wegner, G Salzer, JJ TI Correlation analysis of SFI peculiar velocities SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; cosmology : theory; galaxies : distances and redshifts; large-scale structure of universe ID DARK-MATTER MODELS; DENSITY FIELDS; HUBBLE FLOW; GALAXIES; IRAS; REDSHIFT; PERTURBATIONS; SIMULATIONS; PARAMETERS; SCALE AB We present results of a statistical analysis of the SFI catalog of peculiar velocities, a recently completed survey of spiral field galaxies with I-band Tully-Fisher distances. The velocity field statistic utilized is the velocity correlation function, psi(1)(r), originally introduced by Gorski et al. The analysis is performed in redshift space so as to circumvent potential ambiguities connected with inhomogeneous Malmquist bias corrections. The results from the SFI sample are compared with linear-theory predictions for a class of cosmological models. We generate a large set of mock samples, extracted from N-body simulations, which are used to assess the reliability of our analysis and to estimate the associated uncertainties. We assume a class of cold dark matter-like power spectrum models, specified by sigma(8), the rms fluctuation amplitude within a sphere of 8 h(-1) Mpc radius, and by the shape parameter, Gamma. Defining eta(8) = sigma(8) Omega(0)(0.6), we find that the measured psi(1)(r) implies a degenerate constraint in the (eta(8),Gamma)-plane, with eta(8) = 0.3 +/- 0.1(Gamma/0.2)(0.5) at the 2 sigma level for the inverse Tully-Fisher (ITF) calibration presented in this paper. We investigate how much this constraint changes as we account for uncertainties in the analysis method and uncertainties in the distance indicator, and we consider alternative ITF calibrations. We find that both changing the error-weighting scheme and selecting galaxies according to different limiting line widths has a negligible effect. On the contrary, the model constraints are quite sensitive to the ITF calibration. The other ITF calibrations, by Giovanelli et al. and da Costa et al, both yield, for Gamma = 0.2, a best-fit value of eta(8) similar or equal to 0.6. C1 Univ Trieste, Dipartimento Astron, Ist Nazl Fis Nucl, Sez Trieste, I-34100 Trieste, Italy. Ist Nazl Fis Nucl, Sez Perugia, I-34100 Trieste, Italy. Observ Nacl, BR-20921400 Sao Cristovao, RJ, Brazil. Fermi Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. Cornell Univ, Natl Astron & Ionosphere Ctr, Ithaca, NY 14953 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14953 USA. European So Observ, Space Telescope European Coordinating Facil, D-85748 Garching, Germany. Dartmouth Coll, Dept Phys & Astron, Hanover, NH 03755 USA. Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. RP Borgani, S (reprint author), Univ Trieste, Dipartimento Astron, Ist Nazl Fis Nucl, Sez Trieste, Via Tiepolo 11, I-34100 Trieste, Italy. OI Borgani, Stefano/0000-0001-6151-6439 NR 48 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 2000 VL 119 IS 1 BP 102 EP 110 DI 10.1086/301154 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 280NW UT WOS:000085109700011 ER PT J AU Maoz, D Edelson, R Nandra, K AF Maoz, D Edelson, R Nandra, K TI A possible 100 day X-ray-to-optical lag in the variations of the Seyfert 1 nucleus NGC 3516 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3516); galaxies : Seyfert; X-rays ID SHORT-TIMESCALE VARIABILITY; ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; MULTIWAVELENGTH OBSERVATIONS; ACCRETION DISKS; NGC-4151; CONTINUUM; SPECTRUM; NGC-5548; NGC-7469 AB We present optical broadband (B and R) observations of the Seyfert 1 nucleus NGC 3516, obtained at Wise Observatory from 1997 March to 1998 September contemporaneously with the X-ray 2-10 keV measurements of RXTE. The cross-correlation function shows a positive peak when the optical variations lead the X-rays by similar to 100 days, and anticorrelation peaks at various leads and delays between the X-rays and the optical. We show that the putative correlation signal at 100 days is entirely due to the slow (greater than or similar to 30 day) components of the light curves. During the first year of this monitoring, smoothed versions of the light curves are nearly identical copies of each other, but scaled in amplitude and shifted in time. However, for the next 200 days, the X-ray and optical variations are clearly different. During the whole period, the more rapidly changing components of the light curves are uncorrelated at any lag. We consider the detection of these lags tentative and the significance of the correlations uncertain. If the 100 day delay is real, however, one interpretation is that the slowly varying part of the X-ray emission is an echo of the optical emission, Compton scattered from a medium located at, or extending, similar to 50-100 It-days from the optical source. We point out that a possibly analogous phenomenon, a lag between hard and soft X-rays for a given variability timescale, exists in Galactic stellar-mass accretors. Remarkably, in both cases the lag corresponds to a light-travel distance of the order of 10(4) gravitational radii. Alternatively, the lag may not represent a physical size, but some other timescale. For example, it may be the manifestation of an instability propagating inward in an accretion flow, appearing first in the optical and then in the X-rays. In any event, we observe no strong correlation at zero lag, or at the small positive lags expected if the optical continuum were produced by reprocessing of X-rays. An energetically significant reprocessed component in the optical emission of NGC 3516 is thus ruled out by our data. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. Univ Leicester, X Ray Astron Grp, Leicester LE1 7RH, Leics, England. Eureka Sci, Oakland, CA 94602 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Maoz, D (reprint author), Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. EM dani@wise.tau.ac.il NR 37 TC 28 Z9 28 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 2000 VL 119 IS 1 BP 119 EP 125 DI 10.1086/301180 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 280NW UT WOS:000085109700013 ER PT J AU Brandner, W Grebel, EK Chu, YH Dottori, H Brandl, B Richling, S Yorke, HW Points, SD Zinnecker, H AF Brandner, W Grebel, EK Chu, YH Dottori, H Brandl, B Richling, S Yorke, HW Points, SD Zinnecker, H TI HST/WFPC2 and VLT/ISAAC observations of proplyds in the giant HII region NGC 3603 SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; stars : formation; stars : pre-main-sequence; open clusters and associations : individual (NGC 3603); ISM : individual (NGC 3603) ID ORION NEBULA; PROTOSTELLAR DISKS; ADAPTIVE OPTICS; STELLAR CONTENT; STANDARD STARS; PHOTOEVAPORATION; NGC-3603; FLUX; SPECTROSCOPY; DIFFUSION AB We report the discovery of three proplyd-like structures in the giant H II region NGC 3603. The emission nebulae are clearly resolved in narrowband and broadband HST/WFPC2 observations in the optical and broadband VLT/ISAAC observations in the near-infrared. All three nebulae are tadpole shaped, with the bright ionization front at the head facing the central cluster and a fainter ionization front around the tail pointing away from the cluster. Typical sizes are 6000 AU x 20,000 AU The nebulae share the overall morphology of the proplyds (PROto PLanetarY DiskS) in Orion, but are 20 to 30 times larger in size. Additional faint filaments located between the nebulae and the central ionizing cluster can be interpreted as bow shocks resulting from the interaction of the fast winds from the high-mass stars in the cluster with the evaporation flow from the proplyds. Low-resolution spectra of the brightest nebula, which is at a projected separation of 1.3 pc from the cluster, reveal that it has the spectral excitation characteristics of an ultra compact H II region with electron densities well in excess of 10(4) cm(-3). The near-infrared data reveal a point source superposed on the ionization front. The striking similarity of the tadpole-shaped emission nebulae in NGC 3603 to the proplyds in Orion suggests that the physical structure of both types of objects might be the same. We present two-dimensional radiation hydrodynamical simulations of an externally illuminated star-disk-envelope system, which was still in its main accretion phase when first exposed to ionizing radiation from the central cluster. The simulations reproduce the overall morphology of the proplyds in NGC 3603 very well, but also indicate that mass-loss rates of up to 10(-5) M . yr(-1) are required in order to explain the size of the proplyds. Due to these high mass-loss rates, the proplyds in NGC 3603 should only survive approximate to 10(5) yr. Despite this short survival time, we detect three proplyds. This indicates that circumstellar disks must be common around young stars in NGC 3603 and that these particular proplyds have only recently been exposed to their present harsh UV environment. C1 Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Fed Rio Grande Sul, Inst Fis, BR-91500 Porto Alegre, RS, Brazil. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Heidelberg, Inst Theoret Astrophys, D-69121 Heidelberg, Germany. Inst Astrophys, D-14482 Potsdam, Germany. RP Brandner, W (reprint author), Univ Hawaii, Astron Inst, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. NR 47 TC 58 Z9 58 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 2000 VL 119 IS 1 BP 292 EP 301 DI 10.1086/301192 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 280NW UT WOS:000085109700026 ER PT J AU Dayal, A Sahai, R Watson, AM Trauger, JT Burrows, CJ Stapelfeldt, KR Gallagher, JS AF Dayal, A Sahai, R Watson, AM Trauger, JT Burrows, CJ Stapelfeldt, KR Gallagher, JS TI The etched hourglass nebula MyCn 18. II. A spatio-kinematic model SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; planetary nebulae : individual (MyCn 18); stars : AGB and post-AGB; stars : mass loss ID PLANETARY-NEBULAE; RADIATION GASDYNAMICS; MOLECULAR-HYDROGEN; BIPOLAR NEBULAE; STARS; EVOLUTION; ENVELOPES; CO; EMISSION; WIND AB We have observed MyCn18, a young planetary nebula, with Hubble Space Telescope/Wide Field Planetary Camera 2 and have presented the observational results in an earlier paper. Here we present a detailed spatio-kinematic model of H alpha emission from the nebula. We model the hourglass-shaped nebular lobes as thin-walled structures in the shape of modified paraboloids. Variations in the H alpha. surface brightness with radius imply abrupt changes in the exponent of the power-law gas density in the hourglass walls. These density variations might reflect temporal variations in the mass-loss rate of the progenitor asympotic giant branch (AGE) star. Alternatively, they may be a result of the complex interaction between the fast and slow winds. From the H alpha surface brightness variations we infer that the nebula is density-bounded everywhere, except in the vicinity of the dense waist. We derive a total mass of 0.013 M . for the walls of the ionized nebula and an upper limit of 0.006 M . for the mass in the interior. This appears to be a small fraction of the total mass ejected in the AGE phase. The nebular kinematics are well modeled with a radial velocity field where velocity increases with latitude. The density and velocity structures derived from our model are consistent with general predictions of the interacting winds hypothesis for planetary nebula formation. C1 CALTECH, IPAC, JPL, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Nacl Autonoma Mexico, Astron Inst, Morelia 58090, Michoacan, Mexico. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. RP Dayal, A (reprint author), CALTECH, IPAC, JPL, Mail Stop 100-22, Pasadena, CA 91125 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 35 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD JAN PY 2000 VL 119 IS 1 BP 315 EP 322 DI 10.1086/301163 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 280NW UT WOS:000085109700028 ER PT J AU Dieters, SW Vaughan, BA Kuulkers, E Lamb, FK van der Klis, M AF Dieters, SW Vaughan, BA Kuulkers, E Lamb, FK van der Klis, M TI No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE methods : data analysis; stars : binaries : close stars : individual : Sco X-1; stars : individual : Cyg X-2; stars : neutron; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; X-RAY BINARIES; SCORPIUS X-1; MULTIWAVELENGTH CAMPAIGN; SPECTRAL BEHAVIOR; BRANCH; GINGA; GX5-1; FLUX AB We have measured the phase-delay and rms amplitude spectra of Cyg X-2 and Sco X-l. Using EXOSAT data from the normal branch of Cyg X-2 we confirm earlier (Ginga) results, showing that at an energy near 6 keV there is both a minimum in the quasi-periodic oscillations QPO rms amplitude spectrum and a 150 degrees phase jump in the QPO phase-delay spectrum. Surprisingly, using EXOSAT and Ginga data, we find no evidence for a phase jump of this kind in the phase-delay spectrum of Sco X-l on either the normal or flaring branch. Upper limits (90% confidence) of 42 degrees can be set on any phase jump in the energy range 2-10 keV on the normal branch, and 88 degrees on the flaring branch. The QPO rms amplitude spectrum of Sco X-l increases steeply with energy on both the normal and flaring branches. These results suggest that the X-ray spectrum pivots about an energy of less than or similar to 2keV or greater than or similar to 10 keV or that normal branch QPO of Sco X-l does not have a pivoting spectrum. We discuss the implications of these results in terms of the radiation-hydrodynamic model for normal branch QPO. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Max Planck Inst Astrophys, D-85740 Garching, Germany. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. RP Dieters, SW (reprint author), NASA, George C Marshall Space Flight Ctr, SD-50, Huntsville, AL 35812 USA. EM stefan.dieters@msfc.nasa.gov NR 39 TC 8 Z9 8 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 2000 VL 353 IS 1 BP 203 EP 210 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 275TD UT WOS:000084835500022 ER PT J AU Nakariakov, VM Ofman, L Arber, TD AF Nakariakov, VM Ofman, L Arber, TD TI Nonlinear dissipative spherical Alfven waves in solar coronal holes SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE magnetohydrodynamics (MHD); waves; methods : analytical; Sun : corona; Sun : oscillations ID WIND; EVOLUTION AB The weakly nonlinear dynamics of linearly polarized, spherical Alfven waves in coronal holes is investigated. An evolutionary equation, combining the effects of spherical stratification, nonlinear steepening and dissipation due to shear viscosity is derived. The equation is a spherical analog of the scalar Cohen-Kulsrud-Burgers equation. Three main stages of the wave evolution are distinguished: geometrical amplification, wave breaking and enhanced dissipation. The wave dissipation is dramatically increased by the nonlinear transfer of energy to smaller scales. The scenario of the nonlinear dissipation is practically independent of viscosity. The dissipation rate is stronger for highest amplitudes, and depends weakly on the wave period and the temperature of the atmosphere. Waves with periods less than 300 s and initial amplitudes about 2-3 % of the Alfven speed at the base of the corona are subject to the nonlinear steepening and dissipation in less than 10 solar radii. For the Alfven waves with amplitudes less than 25 km s(-1) at the base of the corona, the maximum amplitude of up to 200 km s(-1) is reached at several solar radii. The nonlinear distortion of the wave shape is accompanied by the generation of longitudinal motions and density perturbations. C1 Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. Univ St Andrews, Sch Math & Computat Sci, St Andrews KY16 9SS, Fife, Scotland. RP Nakariakov, VM (reprint author), Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. EM valery@dcs.st-and.ac.uk RI Nakariakov, Valery/E-2375-2013; Lee, SungHwan/O-2563-2013 OI Nakariakov, Valery/0000-0001-6423-8286; NR 25 TC 42 Z9 45 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 2000 VL 353 IS 2 BP 741 EP 748 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277MQ UT WOS:000084937700035 ER PT J AU Kashlinsky, A Odenwald, S AF Kashlinsky, A Odenwald, S TI Clustering of the diffuse infrared light from the COBE DIRBE maps. III. Power spectrum analysis and excess isotropic component of fluctuations SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; diffuse radiation; infrared : galaxies ID CAMPANAS REDSHIFT SURVEY; BACKGROUND EXPERIMENT; GALACTIC POLE; DENSITY FIELD; IRAS GALAXIES; STAR COUNTS; EVOLUTION; UNIVERSE; DESIGN; C(0) AB The cosmic infrared background (CIB) radiation is the cosmic repository for energy release throughout the history of the universe. The spatial fluctuations of the CIB resulting from galaxy clustering are expected to be at least a few percent on scales of a degree, depending on the luminosity and clustering history of the early universe. Using the all-sky data from the COBE DIRBE instrument at wavelengths 1.25-100 mu m, we attempt to measure the CIB fluctuations. In the near-IR, foreground emission is dominated by small-scale structure due to stars in the Galaxy. There we find a strong correlation between the amplitude of the fluctuations and Galactic latitude after removing bright foreground stars. Using data outside the Galactic plane (\ b \ > 20 degrees) and away from the center (90 degrees < l < 270 degrees), we extrapolate the amplitude of the fluctuations to csc \ b \ = 0. We find positive intercepts of delta F-rms = 15.5(-7.0)(+3.7), 5.9(-3.7)(+1.6), 2.4(-0.9)(+0.5), and 2.0(-0.5)(+0.25) nW m(-2) sr(-1) at 1.25, 2.2, 3.5, and 4.9 mu m, respectively, where the errors are the range of 92% confidence limits. For color subtracted maps between band 1 and 2 we find the isotropic part of the fluctuations at 7.6(-2.4)(+1.2) nW m(-2) sr(-1). Based on detailed numerical and analytic models, this residual is not likely to originate from the Galaxy, our clipping algorithm, or instrumental noise. We demonstrate that the residuals from the lit used in the extrapolation are distributed isotropically and suggest that this extra variance may result from structure in the GIB. We also obtain a positive intercept from a linear combination of maps at 1.25 and 2.2 mu m. For 2 degrees < theta < 15 degrees, a power-spectrum analysis yields firm upper limits of (theta/5 degrees) x delta F-rms(theta) < 6, 2.5, 0.8, and 0.5 nW m(-2) sr(-1) at 1.25, 2.2, 3.5, and 4.9 mu m, respectively. From 10 to 100 mu m, the dominant foregrounds are emission by dust in the solar system and the Galaxy. The upper limits on the CIB fluctuations are below 1 nW m-2 sr-l there and are lowest ( less than or equal to 0.5 nW m(-2) sr(-1)) at 25 mu m. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NORDITA, DK-2100 Copenhagen, Denmark. RP Kashlinsky, A (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 48 TC 51 Z9 51 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 74 EP 95 DI 10.1086/308172 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100006 ER PT J AU Kataoka, J Takahashi, T Makino, F Inoue, S Madejski, GM Tashiro, M Urry, CM Kubo, H AF Kataoka, J Takahashi, T Makino, F Inoue, S Madejski, GM Tashiro, M Urry, CM Kubo, H TI Variability pattern and the spectral evolution of the BL lacertae object PKS 2155-304 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (PKS 2155-304); gamma rays : theory; radiation mechanisms : nonthermal; X-rays : galaxies ID GAMMA-RAY EMISSION; SELF-COMPTON PROCESS; X-RAY; RELATIVISTIC JETS; MULTIWAVELENGTH OBSERVATIONS; SPHERICAL GEOMETRIES; BLAZARS; PKS-2155-304; RADIATION; FLARE AB The TeV blazar PKS 2155 - 304 was monitored with the X-ray satellite ASCA in 1994 May as part of a multiwavelength campaign from the radio to X-ray bands. At the beginning of the two-day continuous observation, we detected a lame flare, in which the 2-10 keV flux changed by a factor of 2 on a timescale of 3 x 10(4) s. During the hare, the increase in the hard X-ray flux clearly preceded that observed in the soft X-rays, with the spectral evolution tracking a "clockwise loop" in the flux versus photon index plane. Ascribing the energy-dependent variability to differential synchrotron cooling of relativistic electrons, we estimate the magnetic field B in the emission region. We tested two different methods of comparing the time series in various X-ray bands: (1) fitting the light curves to a Gaussian function and searching for the time shift of the peak of the flare, and (2) calculating the discrete correlation function. Both methods yielded a consistent solution of B similar to 0.1 G; We also found that the flare amplitude becomes larger as the photon energy increases, while the duration of the flare stays roughly constant throughout the ASCA energy band (0.7-7.5 keV). In the framework of the time-dependent synchrotron self-Compton model in a homogeneous region, we consider a flare where the maximum Lorentz factor (gamma(max)) of the injected electrons increases uniformly throughout the emission volume. The temporal evolution of spectra as well as the light curves were reproduced with the physical parameters self-consistently determined from seven observables. We obtained B similar to 0.1-0.2 G and a region size R similar to 10(-2) pc for relativistic beaming with a Doppler factor of delta similar to 20-30. We discuss the significance of light-travel time effects. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Inst Cosm Ray Res, Tanashi, Tokyo 1888502, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan. RP Kataoka, J (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan. RI Tashiro, Makoto/J-4562-2012; Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 56 TC 107 Z9 108 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 243 EP 253 DI 10.1086/308154 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100021 ER PT J AU Kaiser, ME Bradley, LD Hutchings, JB Crenshaw, DM Gull, TR Kraemer, SB Nelson, CH Ruiz, J Weistrop, D AF Kaiser, ME Bradley, LD Hutchings, JB Crenshaw, DM Gull, TR Kraemer, SB Nelson, CH Ruiz, J Weistrop, D TI The resolved narrow-line region in NGC 4151 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 4151); galaxies : kinematics and dynamics; galaxies : nuclei; galaxies : Seyfert ID SEYFERT-GALAXIES; RADIO NUCLEUS; NGC-4151; KINEMATICS; PROFILES; DISK; GAS AB We present slitless spectra of the narrow-line region (NLR) in NGC 4151 from the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope and investigate the kinematics and physical conditions of the emission-line clouds in this region. Using medium resolution (similar to 0.5 Angstrom) slitless spectra at two roll angles and narrow-band undispersed images, we have mapped the NLR velocity field from 1.2 kpc to within 13 pc (H-0 = 75 km s(-1) Mpc(-1)) of the nucleus. The inner biconical cloud distribution exhibits recessional velocities relative to the nucleus to the NE and approaching velocities to the SW of the nucleus. We find evidence for at least two kinematic components in the NLR. One kinematic component is characterized by low velocities and low velocity dispersions (LVLVD clouds: \ v \ < 400 km (-1), and Delta v < 130 km s(-1)). This population extends through the NLR, and their observed kinematics may be gravitationally associated with the host galaxy. Another component is characterized by high velocities and high velocity dispersions (HVHVD clouds: 400 < \ v \ less than or similar to 1700 km s(-1), Delta v greater than or equal to 130 km s(-1)). This set of clouds is located within 1." 1 (similar to 70 pc) of the nucleus and has radial velocities that are too high to be gravitational in origin but show no strong correlation between velocity or velocity dispersion and the position of the radio knots. Outflow scenarios will be discussed as the driving mechanism for these HVHVD clouds. We also find clouds characterized by low velocities and high velocity dispersions (LVHVD clouds: \ v \ < 400 km s(-1), Delta v greater than or equal to 130 km s(-1)). These clouds are located within 3." 2 (similar to 200 pc) of the nucleus. It is not clear if the LVHVD clouds are HVHVD clouds whose low velocities are the result of projection effects. Within 3." 2 (similar to 200 pc) of the nucleus, the [O III]/H beta ratio declines roughly linearly for both the high-velocity-dispersion (HVD) and LVLVD clouds. Since the ionization parameter is proportional to r(-2)n(-1), it appears that the density, n, must decrease as similar to r(-1) for the clouds within the inner similar to 3." 2. At distances further from the nucleus, the [O III]/H beta ratio is roughly constant. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Kaiser, ME (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 36 TC 61 Z9 61 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 260 EP 275 DI 10.1086/308143 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100023 ER PT J AU Chiang, J Reynolds, CS Blaes, OM Nowak, MA Murray, N Madejski, G Marshall, HL Magdziarz, P AF Chiang, J Reynolds, CS Blaes, OM Nowak, MA Murray, N Madejski, G Marshall, HL Magdziarz, P TI Simultaneous EUVE/ASCA/RXTE observations of NGC 5548 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 5548); galaxies : nuclei; galaxies : Seyfert; ultraviolet : galaxies; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; X-RAY REFLECTION; BLACK-HOLE CANDIDATES; TIME-SERIES ANALYSIS; UNEVENLY SPACED DATA; CYGNUS X-1; ULTRAVIOLET VARIABILITY; NGC-5548; CONTINUUM AB We present simultaneous observations by EUVE, ASCA, and RXTE of the type 1 Seyfert galaxy NGC 5548. These data indicate that variations in the EUV emission (at similar to 0.2 keV) appear to lead similar modulations in higher energy (greater than or similar to keV) X-rays by similar to 10-30 ks. This is contrary to popular models which attribute the correlated variability of the EUV, UV and optical emission in type 1 Seyferts to reprocessing of higher energy radiation. This behavior instead suggests that the variability of the optical through EUV emission is an important driver for the variability of the harder X-rays which are likely produced by thermal Comptonization. We also compute the power density spectra at the various energy bands probed by these observations. Over 10-300 ks timescales, the emission in EUV shows about a factor of two greater rms variability than that of the 2-20 keV RXTE-PCA band-18. +/- 1.4% versus 7.4 +/- 0.6%. On longer timescales, we construct a PDS from 1-12 keV RXTE-ASM data which shows evidence for a break at about 6 x 10(-8) Hz. Furthermore, we find that the combined RXTE-ASM/PCA power spectrum is remarkably similar in shape to PDSs found for the low/hard states of Galactic black hole candidates such as Cygnus X-1. The implied scaling factor of similar to 10(6) is comparable to the expected mass ratio for these two objects. In addition, we investigate the spectral characteristics of the fluorescent iron K alpha line and Compton reflection emission. In contrast to prior measurements of these spectral features, we find that the iron K alpha line has a relatively small equivalent width (W-K alpha similar to 100 eV) and that the reflection component is consistent with a covering factor which is significantly less than unity (Omega/2 pi similar to 0.4-0.5). Notably, although the 2-10 keV X-ray flux varies by similar to +/-25% and the derived reflection fraction appears to be constant throughout our observations, the flux in the iron K alpha line is also constant. This behavior is difficult to reconcile in the context of standard Compton reflection models. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 55 TC 130 Z9 131 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 292 EP 305 DI 10.1086/308178 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100025 ER PT J AU Moskalenko, IV Strong, AW AF Moskalenko, IV Strong, AW TI Anisotropic inverse Compton scattering in the Galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; diffuse radiation; Galaxy : general; gamma rays : observations; gamma rays : theory; ISM : general ID GAMMA-RAY EMISSION; EGRET OBSERVATIONS; SPECTRUM; ELECTRONS AB The inverse Compton scattering of interstellar photons off cosmic-ray electrons seems to play a more important role in the generation of diffuse emission from the Galaxy than thought before. The background radiation field of the Galaxy is highly anisotropic since it is dominated by the radiation from the Galactic plane. An observer in the Galactic plane thus sees mostly head-on scatterings even if the distribution of the cosmic-ray electrons is isotropic. This is especially evident when considering inverse Compton scattering by electrons in the halo, i.e., the diffuse emission at high Galactic latitudes. We derive formulae for this process and show that the anisotropy of the interstellar radiation field has a significant effect on the intensity and angular distribution of the Galactic diffuse gamma-rays, which can increase the high-latitude Galactic gamma-ray flux up to 40%. This effect should be taken into account when calculating the Galactic emission for extragalactic background estimates. C1 Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow 119899, Russia. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RP Moskalenko, IV (reprint author), NASA, Goddard Space Flight Ctr, LHEA Code 660, Greenbelt, MD 20771 USA. RI Moskalenko, Igor/A-1301-2007 OI Moskalenko, Igor/0000-0001-6141-458X NR 26 TC 54 Z9 54 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 357 EP 367 DI 10.1086/308138 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100031 ER PT J AU Hollis, JM Koupelis, T AF Hollis, JM Koupelis, T TI R Aquarii jet: Lorentz force-driven parcel model SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : symbiotic; ISM : individual (R Aquarii); stars : fundamental parameters; stars : magnetic fields ID KINK INSTABILITY; BINARY-SYSTEM; RESOLUTION; SPECTROSCOPY; SHOCK AB The R Aqr symbiotic star system shows directed ow in the form of individual jet parcels. A parcel model for the R Aqr jet is developed that depends upon the strong stellar magnetic field of the rotating hot companion in the system. The model accounts for observed velocities seen in both the radio and ultraviolet regimes and for helical structure seen in ultraviolet emission, and suggests a parcel structure with its ultraviolet emission forming a low-density sheath surrounding its radio region, which is denser by a factor of similar to 30. The model predicts that the rotation of the hot companion is similar to 18 yr, which is a significant fraction of the similar to 44 yr orbital period, and frozen magnetic field flux conservation suggests that the hot companion has a surface held between 9 x 10(7) and 4.6 x 10(9) G if it is a subdwarf of radius 7 x 10(9) cm, or, alternatively, between 4.4 x 10(9) and 2.3 x 10(11) G if it is a white dwarf of radius 10(9) cm. The implications of such a model are discussed. C1 NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Greenbelt, MD 20771 USA. Univ Wisconsin, Wausau, WI 54401 USA. RP NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Code 930, Greenbelt, MD 20771 USA. NR 23 TC 12 Z9 12 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 2000 VL 528 IS 1 BP 418 EP 425 DI 10.1086/308152 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100036 ER PT J AU Vinas, AF Wong, HK Klimas, AJ AF Vinas, AF Wong, HK Klimas, AJ TI Generation of electron suprathermal tails in the upper solar atmosphere: Implications for coronal heating SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; plasmas; Sun : chromosphere; Sun : corona; waves ID TRANSITION REGION; VELOCITY FILTRATION; WAVES; WIND; MODEL; ION; MECHANISMS; STRENGTHS; HOLES AB We present a mechanism for the generation of non-Maxwellian electron distribution function in the upper regions of the solar atmosphere in the presence of collisional damping. It is suggested that finite-amplitude, low-frequency, obliquely propagating electromagnetic waves can carry a substantial electric field component parallel to the mean magnetic field that can be significantly larger than the Dreicer electric field. This long-wavelength electric fluctuation is capable of generating high-frequency electron plasma oscillations and low-frequency ion acoustic-like waves. The analysis has been performed using 1-1/2D Vlasov and PIC numerical simulations in which both electrons and ions are treated kinetically and self consistently. The simulation results indicate that high-frequency electron plasma oscillations and low-frequency ion acoustic-like waves are generated. The high-frequency electron plasma oscillation drives electron plasma turbulence, which subsequently is damped out by the background electrons. The turbulence damping results in electron acceleration and the generation of non-Maxwellian suprathermal tails on timescales short compared to collisional damping. Bulk heating also occurs if the fluctuating parallel electric field is strong enough. This study suggests that finite-amplitude, low-frequency, obliquely propagating electromagnetic waves can play a significant role in the acceleration and heating of the solar corona electrons and in the coupling of medium and small-scale phenomena. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Aurora Sci Inc, San Antonio, TX 78228 USA. RP Vinas, AF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692, Greenbelt, MD 20771 USA. NR 36 TC 60 Z9 60 U1 3 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP 509 EP 523 DI 10.1086/308151 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PC UT WOS:000084941100045 ER PT J AU Hurley, K Strohmayer, T Li, P Kouveliotou, C Woods, P van Paradijs, J Murakami, T Hartmann, D Smith, I Ando, M Yoshida, A Sugizaki, M AF Hurley, K Strohmayer, T Li, P Kouveliotou, C Woods, P van Paradijs, J Murakami, T Hartmann, D Smith, I Ando, M Yoshida, A Sugizaki, M TI ASCA observation of the quiescent X-ray counterpart to SGR 1627-41 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; stars : neutron; supernova remnants; X-rays : stars AB We present a 2-10 keV ASCA observation of the field around the soft gamma repeater SGR 1627-41. A quiescent X-ray source, whose position is consistent both with that of a recently discovered BeppoSAX X-ray source and with the Interplanetary Network localization for this soft gamma repeater, was detected in this observation. In 2-10 keV X-rays, the spectrum of the X-ray source may be fit equally well by a power-law, blackbody, or bremsstrahlung function, with unabsorbed flux approximate to 5 x 10(-12) ergs cm(-2) s(-1). We do not confirm a continuation of a fading trend in the flux, and we find no evidence for periodicity, both of which were noted in the earlier BeppoSAX observations. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, Amsterdam, Netherlands. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Natl Space Dev Agcy Japan, Space Utilizat Res Program, Tsukuba Space Ctr, Tsukuba, Ibaraki 3058505, Japan. RP Hurley, K (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NR 11 TC 17 Z9 17 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 1 PY 2000 VL 528 IS 1 BP L21 EP L23 DI 10.1086/312424 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 277PE UT WOS:000084941300006 ER PT J AU Lamarre, JM Ade, PAR Benoit, A de Bernardis, P Bock, J Bouchet, F Bradshaw, T Charra, J Church, S Couchot, F Delabrouille, J Efstathiou, G Giard, M Giraud-Heraud, Y Gispert, R Griffin, M Lange, A Murphy, A Pajot, F Puget, JL Ristorcelli, I AF Lamarre, JM Ade, PAR Benoit, A de Bernardis, P Bock, J Bouchet, F Bradshaw, T Charra, J Church, S Couchot, F Delabrouille, J Efstathiou, G Giard, M Giraud-Heraud, Y Gispert, R Griffin, M Lange, A Murphy, A Pajot, F Puget, JL Ristorcelli, I TI The high frequency instrument of Planck: Design and performances SO ASTROPHYSICAL LETTERS & COMMUNICATIONS LA English DT Article; Proceedings Paper CT Workshop on Cosmic Microwave Background and the Planck Mission CY JUN 22-25, 1999 CL CANTABRIA, SPAIN SP UIMP, CICYT, Univ Cantabria, Inst Fis Cantabria, Dpto Fis Moderns, Fac Ciencias C1 Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. CNRS, Ctr Rech Tres Basses Temp, F-38042 Grenoble, France. Univ La Sapienza, Dipartimento Fis G Marconi, Grp Cosmol Sperimentale, I-00185 Rome, Italy. Inst Astrophys, F-75014 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. CALTECH, Observ Cosmol, Pasadena, CA 91125 USA. Univ Paris 11, IN2P3, LAL, F-91405 Orsay, France. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Ctr Etud Spatiale Rayonnements, F-31029 Toulouse, France. Coll France, PCC, F-75231 Paris 05, France. Natl Univ Ireland, Maynooth, Kildare, Ireland. RP Lamarre, JM (reprint author), Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. RI Bouchet, Francois/B-5202-2014; OI de Bernardis, Paolo/0000-0001-6547-6446 NR 8 TC 26 Z9 26 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0888-6512 J9 ASTROPHYS LETT COMM JI Astrophys. Lett. Comm. PY 2000 VL 37 IS 3-6 BP 161 EP + PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337RJ UT WOS:000088375200004 ER PT J AU Bhandari, P Bowman, RC Chave, RG Lindensmith, CA Morgante, G Paine, C Prina, M Wade, LA AF Bhandari, P Bowman, RC Chave, RG Lindensmith, CA Morgante, G Paine, C Prina, M Wade, LA TI Sorption cryocooler development for the Planck Surveyor mission SO ASTROPHYSICAL LETTERS & COMMUNICATIONS LA English DT Article; Proceedings Paper CT Workshop on Cosmic Microwave Background and the Planck Mission CY JUN 22-25, 1999 CL CANTABRIA, SPAIN SP UIMP, CICYT, Univ Cantabria, Inst Fis Cantabria, Dpto Fis Moderns, Fac Ciencias DE sorption; cryocooler; Joule-Thomson; metal hydride AB We are developing metal-hydride based sorption cryocoolers for the Planet Surveyor mission. The sorption coolers work by thermally cycling a metal-hydride to absorb and desorb hydrogen gas, which is used as the working fluid in a Joule-Thomson refrigerator. Pressure ratios of 100:1 or more can be achieved by varying the temperature of the compressor by a factor of 2-3. The major advantages of sorption coolers are that they are truly vibration-free and can be readily scaled to perform over a wide range of cooling powers. We present here a review of sorption cooler operation, important factors in the design of coolers, and the details of the design of a 20 K cooler system for the Planet mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Politecn Milan, Dipartimento Energet, I-20133 Milan, Italy. CNR, Ist Tesre, I-40126 Bologna, Italy. Osservatorio Astron Trieste, I-34131 Trieste, Italy. RP Bhandari, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Bowman, Robert/0000-0002-2114-1713 NR 5 TC 10 Z9 11 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 0888-6512 J9 ASTROPHYS LETT COMM JI Astrophys. Lett. Comm. PY 2000 VL 37 IS 3-6 BP 227 EP 237 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337RJ UT WOS:000088375200011 ER PT J AU Danks, AC AF Danks, AC TI Studies of the ISM in the Vela supernova remnant SO ASTROPHYSICS AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Conference on Astrophysical Dynamics CY APR 14-16, 1999 CL UNIV EVORA, EVORA, PORTUGAL SP Geophys Ctr Evora HO UNIV EVORA ID LOW-DENSITY REGIONS; INTERSTELLAR ABSORPTION; GAS; HD-72127A; GALAXY; LINES AB Recent observations of the Vela SNR in the ISM species Ca II and Na I are presented and discussed in the context of the "break-down'' of the Spitzer-Routly effect. Variations in line profiles with time are demonstrated, eventually through a statistical approach a description of cloud structure will be possible. The IS lines in similar to 70 sightlines are used to determine an accurate distance to the Vela SNR of 250 +/- 30 pc. Finally a discussion of future observations are given relating information obtained from measurements of near-by ISM to more distant intergalactic medium. C1 Raytheon ITSS, Greenbelt, MD 20771 USA. GSFC, Greenbelt, MD 20771 USA. RP Danks, AC (reprint author), Raytheon ITSS, Code 683 0, Greenbelt, MD 20771 USA. NR 20 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 0004-640X J9 ASTROPHYS SPACE SCI JI Astrophys. Space Sci. PY 2000 VL 272 IS 1-3 BP 127 EP 133 DI 10.1023/A:1002607404565 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 351DH UT WOS:000089142200018 ER PT B AU Sahai, R Su, KYL Kwok, S Dayal, A Hrivnak, BJ AF Sahai, R Su, KYL Kwok, S Dayal, A Hrivnak, BJ BE Kastner, JH Soker, N Rappaport, SA TI Near-infrared continuum, H-2 line and polarimetric imaging of three proto-planetary nebulae with HST SO ASYMMETRICAL PLANETARY NEBULAE II: FROM ORIGINS TO MICROSTRUCTURES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 2nd Meeting of the Asymmetrical Planetary Nebulae CY AUG 03-06, 1999 CL MIT, CAMBRIDGE, MA HO MIT ID PROTOPLANETARY NEBULA AB As part of a comprehensive study of the origins of aspherical structure in planetary nebulae, we report here high-resolution near-infrared images of 3 bipolar protoplanetary nebulae (PPN), Roberts 22, Hen 401, and the Boomerang Nebula, obtained with NICMOS/HST. The Hubble images reveal a rich and complex morphological structure of the circumstellar material for each of these objects. Although all 3 PPNe are bipolar, their morphologies differ substantially in detail, with important implications for current theories for the formation and shaping of aspherical PN. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kwok, Sun/D-3080-2009 OI Kwok, Sun/0000-0001-7708-081X NR 10 TC 7 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-026-9 J9 ASTR SOC P PY 2000 VL 199 BP 167 EP 170 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39J UT WOS:000088231900029 ER PT B AU Sahai, R AF Sahai, R BE Kastner, JH Soker, N Rappaport, SA TI Hubble Space Telescope observations of young planetary nebulae SO ASYMMETRICAL PLANETARY NEBULAE II: FROM ORIGINS TO MICROSTRUCTURES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 2nd Meeting of the Asymmetrical Planetary Nebulae CY AUG 03-06, 1999 CL MIT, CAMBRIDGE, MA HO MIT ID CIRCUMSTELLAR ENVELOPES; AGB STARS; EVOLUTION; EMISSION; JETS AB We present results from an ongoing Hubble Space Telescope Her imaging survey of young planetary nebulae (PNe), selected on the basis of their low excitation characteristics. All objects imaged so far show highly aspherical morphology, with a majority characterised by multipolar bubbles distributed roughly point-symmetrically around the central star. In some objects, bipolar ansae or collimated radial structures are seen, indicating title presence of jets, whereas in others bright structures near the minor axes indicate the presence of disks or torii. The complexity, organization and symmetry of the above structures leads us to propose that the primary agent for shaping PNe are high-speed collimated outflows or jets which operate during the late AGE and/or early post-AGB evolutionary phase. These outflows carve out a complex imprint within an intrinsically spherical AGE circumstellar envelope (CSE). Subsequent expansion of a hot, tenuous stellar wind from the post-AGE star inside the imprinted AGE CSE then produces the observed PN, whose shape and structure depend in detail on how the characteristics of the jets change with time. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, MS183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 33 TC 25 Z9 25 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-026-9 J9 ASTR SOC P PY 2000 VL 199 BP 209 EP 216 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39J UT WOS:000088231900038 ER PT J AU Singh, HB Viezee, W Chen, Y Bradshaw, J Sandholm, S Blake, D Blake, N Heikes, B Snow, J Talbot, R Browell, E Gregory, G Sachse, G Vay, S AF Singh, HB Viezee, W Chen, Y Bradshaw, J Sandholm, S Blake, D Blake, N Heikes, B Snow, J Talbot, R Browell, E Gregory, G Sachse, G Vay, S TI Biomass burning influences on the composition of the remote South Pacific troposphere: analysis based on observations from PEM-Tropics-A SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE trace chemicals; biomass burning pollution; remote atmospheres ID REACTIVE NITROGEN; NORTH PACIFIC; OZONE; CHEMISTRY; EMISSIONS; ATLANTIC; PLUMES; IMPACT; FALL AB Airborne, in situ measurements from PEM-Tropics-A (September/October 1996) are analyzed to show the presence of distinct pollution plumes in the middle-tropical troposphere of the remote South Pacific (10-30 degrees S). These elevated plumes cause a relative maximum at about 5-7 km altitude in the vertical distribution of primary and secondary species characteristic of fuel combustion and biomass burning (CO, C-2 H-2, C-2 H-6 CH3 Cl, PAN, O-3) Similar plumes were also observed at mid-latitudes in the middle troposphere during three flights east of New Zealand (40-45 degrees S). In all, pollution plumes with CO larger than 100 ppb were observed 24 times on seven separate flight days south of the equator. The observed plumes were frequently embedded in very dry air. Ten-day back trajectory analysis supports the view that these originated from the biomass burning regions of South Africa (and South America) and were transported to the South Pacific along long-distance subsiding trajectories. The chemical composition of the southern Pacific troposphere analyzed from the PEM-Tropics-A data is compared with data from the tropical regions of the northern Pacific (PEM-West-A) and southern Atlantic (TRACE-A) during the same Sept/Oct time period. Sizable perturbations in the abundance of ozone and its key precursors, resulting from the transport of pollution originating from biomass burning sources, are observed in much of the Southern Hemispheric troposphere. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Univ Calif Irvine, Irvine, CA 92717 USA. Univ Rhode Isl, Narragansett, RI 02882 USA. Univ New Hampshire, Durham, NH 03824 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Singh, HB (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 26 TC 40 Z9 41 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PY 2000 VL 34 IS 4 BP 635 EP 644 DI 10.1016/S1352-2310(99)00380-5 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 273GY UT WOS:000084700600012 ER PT J AU Engel, A Muller, R Schmidt, U Carslaw, KS Stachnik, RA AF Engel, A Muller, R Schmidt, U Carslaw, KS Stachnik, RA TI Indications of heterogeneous chlorine activation on moderately cold aerosol based on chlorine observations in the Arctic stratosphere SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE chlorine; heterogeneous chemistry; stratosphere; stratospheric aerosol ID ANTARCTIC STRATOSPHERE; WINTER STRATOSPHERE; OZONE DEPLETION; CLOUD FORMATION; CHEMISTRY; PARTICLES; HNO3; TRAJECTORIES; DROPLETS; GROWTH AB During two balloon flights in the Arctic winter in February 1994 two distinctly different vertical profiles of ClO were measured. On 1 February enhanced values of ClO were observed between about 420 and 620 K inside the polar vortex in an air mass that had experienced moderately cold temperatures about 10 h prior to our measurements. In contrast, on 9 February an unstructured vertical profile was observed outside of the vortex with lower mixing ratios of ClO. Based on calculations with a photochemical box trajectory model we show that the observed enhancement in ClO can be explained by heterogeneous processing of chlorine reservoir species on supercooled liquid aerosols. When NAT formation is forced in the model or when lee wave processing is assumed, the mixing ratios of ClO inside the: vortex are overpredicted. Under conditions where air masses are only cooled to low temperatures fur a short period of time this may be a very important chlorine activation mechanism. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Goethe Univ Frankfurt, Inst Meteorol & Geophys, D-60325 Frankfurt, Germany. Forschungszentrum Julich, Inst Stratosphar Chem, Julich, Germany. Max Planck Inst Chem, D-55128 Mainz, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Engel, A (reprint author), Goethe Univ Frankfurt, Inst Meteorol & Geophys, D-60325 Frankfurt, Germany. EM an.engel@meteor.uni-frankfurt.de RI Muller, Rolf/A-6669-2013; Carslaw, Ken/C-8514-2009; Engel, Andreas/E-3100-2014 OI Muller, Rolf/0000-0002-5024-9977; Carslaw, Ken/0000-0002-6800-154X; Engel, Andreas/0000-0003-0557-3935 NR 38 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PY 2000 VL 34 IS 25 BP 4283 EP 4289 DI 10.1016/S1352-2310(00)00210-7 PG 7 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 348TH UT WOS:000089002200006 ER PT J AU Singh, HB Jacob, DJ AF Singh, HB Jacob, DJ TI Future Directions: Satellite observations of tropospheric chemistry SO ATMOSPHERIC ENVIRONMENT LA English DT Editorial Material C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. RP Singh, HB (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. NR 0 TC 10 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PY 2000 VL 34 IS 25 BP 4399 EP 4401 DI 10.1016/S1352-2310(00)00271-5 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 348TH UT WOS:000089002200017 ER PT S AU Howard, RT Book, ML Bryan, TC AF Howard, RT Book, ML Bryan, TC BE Gonglewski, JD Kamerman, G Kohnle, A Schrieber, U Werner, C TI Video-based sensor for tracking 3-dimensional targets SO ATMOSPHERIC PROPAGATION, ADAPTIVE SYSTEMS, AND LASER RADAR TECHNOLOGY FOR REMOTE SENSING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Atmospheric Propagation, Adaptive Systems, and Laser Radar Technology for Remote Sensing CY SEP 25-28, 2000 CL BARCELONA, SPAIN SP European Opt Soc, SPIE, NASA DE video; sensor; guidance; AR&C; AR&D; automated docking; automatic docking ID DOCKING AB The National Aeronautics and Space Administration's (NASA's) Marshall Space Plight Center (MSFC) has been developing and testing video-based sensors for automated spacecraft guidance for several years. The video sensor currently under development is to have a tracking rate of 50 Hz while delivering full 3-dimensional relative information (X, Y, Z, Pitch, Yaw, and Roll.) Prior systems have been developed and tested in both open-loop and closed-loop simulations. The prototype Video Guidance Sensor (VGS) was built for a flight experiment and performed well on two separate Space Shuttle flights. The VGS uses two wavelengths of light to illuminate a target that has a pattern of filtered retro-reflectors. The filters pass only one wavelength of light and absorb the other. Two fast, successive pictures are taken of the target, each picture illuminated by a different wavelength. When the background picture is subtracted from the foreground, a high signal to noise ratio is achieved, and the target spots are easy to track. The next generation VGS will be using a CMOS imaging chip for higher-speed target tracking and a Texas Instruments DSP for higher-speed image processing. The system is being designed to have lower weight and power requirements than the previous generation, and it will be suitable for other applications. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Howard, RT (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3823-5 J9 P SOC PHOTO-OPT INS PY 2000 VL 4167 BP 242 EP 251 PG 2 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BR99W UT WOS:000168299300027 ER PT S AU Luttgen, G Mendler, M AF Luttgen, G Mendler, M BE Montanari, U Rolim, JDP Welzl, E TI Fully-abstract Statecharts semantics via intuitionistic Kripke models SO AUTOMATA LANGUAGES AND PROGRAMMING SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 27th International Colloquium on Automata Languages and Programming (ICALP 2000) CY JUL 09-15, 2000 CL GENEVA, SWITZERLAND SP Swiss Natl Sci Fdn, Univ Geneva, Dept Comp Sci, INTAS, EATCS ID COMPOSITIONAL SEMANTICS; SYSTEMS AB The semantics of Statecharts macro steps, as introduced by Pnueli and Shalev, lacks compositionality. This paper first analyzes the compositionality problem and traces it back to the invalidity of the Law of the Excluded Middle. It then characterizes the semantics via a particular class of linear, intuitionistic Kripke models, namely stabilization sequences. This yields, for the first time in the literature, a simple fully-abstract semantics which interprets Pnueli and Shalev's concept of failure naturally. The results not only give insights into the semantic subtleties of Statecharts, but also provide a basis for developing algebraic theories for macro steps and for comparing different Statecharts variants. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Sheffield, Dept Comp Sci, Sheffield S1 5DP, S Yorkshire, England. RP NASA, Langley Res Ctr, ICASE, Mail Stop 132C, Hampton, VA 23681 USA. EM luettgen@icase.edu; M.Mendler@dcs.shef.ac.uk NR 18 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67715-1 J9 LECT NOTES COMPUT SC PY 2000 VL 1853 BP 163 EP 174 PG 12 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BQ83K UT WOS:000089738700014 ER PT S AU Poehler, PL Mansfield, AW Rais, H Aboutanos, GB AF Poehler, PL Mansfield, AW Rais, H Aboutanos, GB BE Sadjadi, FA TI Complex data compression techniques: Some new approaches SO AUTOMATIC TARGET RECOGNITION X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 10th Conference on Automatic Target Recognition CY APR 26-28, 2000 CL ORLANDO, FL SP SPIE DE synthetic aperture radar; complex data compression; search and rescue AB The most important parameter in search and rescue is the time it takes to locate the downed aircraft and rescue the survivors. The resulting requirement for wide-area coverage, tine resolution, and day-night all-weather operation dictates the use of a synthetic aperture radar (SAR) sensor. The time urgency combined with the high data volume leads to the need for a new type of data compression. This paper presents and evaluates candidate compression algorithms for SAR raw phase history and for SAR complex imagery. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Poehler, PL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3676-3 J9 P SOC PHOTO-OPT INS PY 2000 VL 4050 BP 197 EP 206 DI 10.1117/12.395564 PG 10 WC Remote Sensing SC Remote Sensing GA BR61P UT WOS:000166958300023 ER PT B AU Airapetian, VS AF Airapetian, VS BE Smith, MA Henrichs, HF Fabregat, J TI Surface magnetic fields in early-type stars SO BE PHENOMENON IN EARLY-TYPE STARS, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting of the Be Phenomenon in Early-Type Stars CY JUN 28-JUL 02, 1999 CL ALICANTE, SPAIN ID CONVECTION; DYNAMOS AB Recent observations imply magnetic activity in atmospheres of early-type stars. We explore the possibility that stressed surface magnetic fields can be driven by inertial oscillations, such as r-modes which are vorticity waves. We show that vorticIAL MOTIOns are able to supply helicity to drive magnetic activity in stellar atmospheres. C1 GSFC, CSC, Sci Programs, Greenbelt, MD 20771 USA. RP Airapetian, VS (reprint author), GSFC, CSC, Sci Programs, Greenbelt, MD 20771 USA. NR 16 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 1-58381-045-5 J9 ASTR SOC P PY 2000 VL 175 BP 334 EP 336 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR85Z UT WOS:000167829400058 ER PT B AU Rummel, JD Meyer, MA AF Rummel, JD Meyer, MA BE Lemarchand, GA Meech, KJ TI NASA's astrobiology program: An overview SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 C1 NASA, Headquarters, Washington, DC 20546 USA. RP Rummel, JD (reprint author), NASA, Headquarters, Washington, DC 20546 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 19 EP 21 PG 3 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700002 ER PT B AU Lissauer, JJ AF Lissauer, JJ BE Lemarchand, GA Meech, KJ TI Planetary formation and the abundance of habitable planets SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID EXTRASOLAR GIANT PLANETS; SYSTEMS; DISKS; DIVERSITY; ACCRETION; NEBULA AB Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. EM lissauer@ringside.arc.nasa.gov NR 30 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 57 EP 64 PG 8 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700007 ER PT B AU Caldwell, DA Borucki, WJ Lissauer, JJ AF Caldwell, DA Borucki, WJ Lissauer, JJ BE Lemarchand, GA Meech, KJ TI The vulcan photometric search for transiting giant planets: Some initial results SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID SUN-LIKE STARS AB The NASA-Ames Research Center's Vulcan camera is being used in a photometric search for extrasolar giant planets by continuously monitoring thousands of stars in its 7 degrees x 7 degrees field of view. In one field, we have achieved sufficient precision to detect Jovian-size planets around approximately 4000 stars. We have detected transit signals with amplitudes ranging from 50% down to similar to 1%. Radial velocity measurements of two of the low amplitude detections indicate that they are binary stars undergoing grazing eclipses. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Caldwell, DA (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Caldwell, Douglas/L-7911-2014 OI Caldwell, Douglas/0000-0003-1963-9616 NR 10 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 101 EP 106 PG 6 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700013 ER PT B AU Dworkin, JP Sandford, SA Allamandola, LJ Deamer, DW Gillette, SJ Zare, RN AF Dworkin, JP Sandford, SA Allamandola, LJ Deamer, DW Gillette, SJ Zare, RN BE Lemarchand, GA Meech, KJ TI Synthesis of large molecules in cometary ice analogs: Physical properties related to self-assembly processes SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 C1 NASA, Ames Res Ctr 045 6, Astrochem Lab, Moffett Field, CA 94035 USA. RP Dworkin, JP (reprint author), NASA, Ames Res Ctr 045 6, Astrochem Lab, Moffett Field, CA 94035 USA. RI Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 5 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 195 EP 196 PG 2 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700029 ER PT B AU Bernstein, MP Sandford, SA Allamandola, LJ Dworkin, JP AF Bernstein, MP Sandford, SA Allamandola, LJ Dworkin, JP BE Lemarchand, GA Meech, KJ TI Formation of prebiotic molecules in interstellar and cometary ices SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID POLYCYCLIC AROMATIC-HYDROCARBONS; EMISSION AB We report here on our lab studies of ice photochemistry of large organic molecules under cometary conditions. We focus on polycyclic aromatic hydrocarbons (PAHs), their photoproducts, and their similarities to molecules seen in living systems today. We note that these kinds of compounds are seen in meteorites and we propose an explanation for both their formation and their observed deuterium enrichments. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bernstein, MP (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. EM mbernstein@mail.arc.nasa.gov; jdworkin@mail.arc.nasa.gov RI Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 17 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 197 EP 204 PG 8 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700030 ER PT B AU Cruikshank, DP Khare, BN AF Cruikshank, DP Khare, BN BE Lemarchand, GA Meech, KJ TI Planetary surfaces of low albedo: Organic material throughout the solar system SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID WATER ICE; OPTICAL-CONSTANTS; DARK MATERIAL; SATELLITES; THOLINS; PHOTOMETRY; EVOLUTION; ORIGIN; ASTEROIDS; LAPETUS AB Materials of low reflectivity (albedo) are common on the surfaces of small bodies in the Solar System (asteroids, comets, satellites, and some planets). There is evidence that macromolecular carbon-bearing materials are one major component of the low albedo material. In the case of asteroids, the low-albedo material appears related to the organic-rich carbonaceous meteorites. At least one Centaur object has the spectral signature of frozen methanol or a related light hydrocarbon. Many planetary satellites and rings appear to have organic solids entrained in their component materials, revealed by their distinctive colors and spectral reflectances. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM dale@ssal.arc.nasa.gov; bkhare@mail.arc.nasa.gov NR 43 TC 6 Z9 6 U1 0 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 253 EP + PG 10 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700036 ER PT B AU Tsapin, AI Goldfeld, MG McDonald, GD Nealson, KH Mohnke, J Moskovitz, B Solheid, P Kemner, KH Orlandini, K AF Tsapin, AI Goldfeld, MG McDonald, GD Nealson, KH Mohnke, J Moskovitz, B Solheid, P Kemner, KH Orlandini, K BE Lemarchand, GA Meech, KJ TI Ferrate(VI) as a possible oxidant on the Martian surface SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID MARS C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsapin, AI (reprint author), CALTECH, Jet Prop Lab, MS 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 315 EP 318 PG 4 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700040 ER PT B AU Tsapin, AI Storrie-Lombardi, M McDonald, GD Nealson, KH AF Tsapin, AI Storrie-Lombardi, M McDonald, GD Nealson, KH BE Lemarchand, GA Meech, KJ TI Application of computer tomography (CT) for search of life in extreme environments SO BIOASTRONOMY'99, A NEW ERA IN BIOASTRONOMY, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on A New Era in Search for life in the Universe (Bioastronomy 99) CY AUG 02-06, 1999 CL KOHALA, HI SP Int Astronom Union, Commiss 51 ID SPIRAL CT C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsapin, AI (reprint author), CALTECH, Jet Prop Lab, MS 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 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 1-58381-044-7 J9 ASTR SOC P PY 2000 VL 213 BP 387 EP 389 PG 3 WC Astronomy & Astrophysics; Biology SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics GA BR93X UT WOS:000168121700053 ER PT B AU Rosenzweig, C AF Rosenzweig, C BE Eaglesham, A Brown, WF Hardy, RWF TI Climate change and agriculture SO BIOBASED ECONOMY OF THE TWENTY-FIRST CENTURY: AGRICULTURE EXPANDING INTO HEALTH, ENERGY, CHEMICALS AND MATERIAL SE NABC REPORT LA English DT Proceedings Paper CT 12th Annual Meeting of the National-Agricultural-Biotechnology-Council CY MAY 11-13, 2000 CL UNIV FLORIDA, ORLANDO, FL SP Natl Agr Biotechnol Council HO UNIV FLORIDA C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rosenzweig, C (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway,Off 510, New York, NY 10025 USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU NATIONAL AGRICULTURAL BIOTECHNOLOGY COUNCIL PI ITHACA PA 159 BIOTECHNOLOGY BLDG CORNELL UNIVERSITY, ITHACA, NY 14853-2703 USA J9 NABC REP PY 2000 VL 12 BP 123 EP 137 PG 15 WC Agricultural Economics & Policy; Biodiversity Conservation SC Agriculture; Biodiversity & Conservation GA BR96M UT WOS:000168184700016 ER PT B AU Levine, JS AF Levine, JS BE Innes, JL Beniston, M Verstraete, MM TI Global biomass burning: A case study of the gaseous and particulate emissions released to the atmosphere during the 1997 fires in Kalimantan and Sumatra, Indonesia SO BIOMASS BURNING AND ITS INTER-RELATIONSHIPS WITH THE CLIMATE SYSTEM SE ADVANCES IN GLOBAL CHANGE RESEARCH LA English DT Proceedings Paper CT Workshop on Biomass Burning and its Inter-Relationships with the Climate System CY SEP, 1998 CL WENGEN, SWITZERLAND SP ENAMORS, Swiss Natl Sci Fdn ID CARBON AB The roles of biomass burning as a global phenomenon and as a contributor to the global budgets of atmospheric gases and particulates are reviewed. To assess the environmental and health impacts of forest fires, knowledge of the gaseous and particulate emissions produced in the fire and released into the atmosphere is required. Extensive and widespread tropical forest and peat fires swept throughout Kalimantan and Sumatra, Indonesia, in 1997. The fires resulted from burning for land clearing and landuse change. However, the severe drought conditions resulting from El Nino caused small land-clearing fires to become large uncontrolled wildfires. It has been estimated that a total of 45,600 km(2) burned between August and December 1997. The gaseous and particulate emissions resulting from these fires are estimated. The emissions of CO2, CO, CH4, NO,, and particulates from the 1997 Kalimantan and Sumatra fires exceeded the emissions of these species from the Kuwait oil fires of 1991. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. RP Levine, JS (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. NR 31 TC 19 Z9 20 U1 0 U2 7 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6107-5 J9 ADV GLOB CHANGE RES PY 2000 VL 3 BP 15 EP 31 PG 17 WC Environmental Sciences; Forestry; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Forestry; Meteorology & Atmospheric Sciences GA BP55C UT WOS:000085482600002 ER PT B AU Cahoon, DR Stocks, BJ Alexander, ME Baum, BA Goldammer, JG AF Cahoon, DR Stocks, BJ Alexander, ME Baum, BA Goldammer, JG BE Innes, JL Beniston, M Verstraete, MM TI Wildland fire detection from space: Theory and application SO BIOMASS BURNING AND ITS INTER-RELATIONSHIPS WITH THE CLIMATE SYSTEM SE ADVANCES IN GLOBAL CHANGE RESEARCH LA English DT Proceedings Paper CT Workshop on Biomass Burning and its Inter-Relationships with the Climate System CY SEP, 1998 CL WENGEN, SWITZERLAND SP ENAMORS, Swiss Natl Sci Fdn ID BOREAL FORESTS; SAVANNA FIRES; AVHRR; BEHAVIOR AB New satellite instruments are currently being designed specifically for fire detection, even though to date the detection of active fires from space has never been an integral part of the design of any in-orbit space mission. Rather, the space-based detection of fires during the last two decades has been exploiting measurements obtained for other objectives. The current fire products have proved to be of great benefit and interest, but their usefulness is not fully understood. Part of the confusion about the utility of these measurements stems from the lack of detailed knowledge about the data and its acquisition. The remote sensing research community has spent considerable time and effort trying to rationalize the usefulness of existing satellite imagery for active fire detection. Unfortunately, uncertainties about instrument capabilities pervades much of this research and the true limits of fire detection from space have not been fully evaluated and understood. To analyze the active fire detection capability of any instrument, the flow of energy from the source to the instrument and the instrument's response to that energy must be considered. For this reason, an approach has been developed that models the energy emitted from surface fires, allowing for the fact that fire is itself a variable phenomenon. The energy transmission is then modelled along its path through the atmosphere and through the instrument's optical system. A fundamental concern is in the estimation of the total surface area that emits the energy which defines a single pixel in the image. Unfortunately, most of the fire detection modelling done to date is based on a misconception about the pixel and its actual size. Rather than using the radiometric footprint size, the instantaneous-field-of-view (IFOV) is used to describe the 'resolution' of the instrument. In fact, the radiometric footprint is considerably larger than the IFOV and greatly affects the energy modelling used to estimate the fire detection thresholds of a particular instrument. Based on knowledge of the radiometric footprint, the fire detection capability of AVHRR, DMSPOLS, and MODIS are reviewed. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Cahoon, DR (reprint author), NASA, Langley Res Ctr, 21 Langley Blvd, Hampton, VA 23665 USA. RI Baum, Bryan/B-7670-2011 OI Baum, Bryan/0000-0002-7193-2767 NR 31 TC 9 Z9 9 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6107-5 J9 ADV GLOB CHANGE RES PY 2000 VL 3 BP 151 EP 169 DI 10.1007/0-306-47959-1_9 PG 19 WC Environmental Sciences; Forestry; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Forestry; Meteorology & Atmospheric Sciences GA BP55C UT WOS:000085482600009 ER PT J AU Schweighofer, KJ Pohorille, A AF Schweighofer, KJ Pohorille, A TI Computer simulation of ion channel gating: The M-2 channel of influenza A virus in a lipid bilayer SO BIOPHYSICAL JOURNAL LA English DT Article ID A VIRUS; MOLECULAR-DYNAMICS; M2 CHANNEL; TRANSMEMBRANE DOMAIN; PROTON-TRANSFER; WATER; PROTEIN; MODEL; SELECTIVITY; ACTIVATION AB The transmembrane fragment of the influenza virus M-2 protein forms a homotetrameric channel that transports protons. In this paper, we use molecular dynamics simulations to help elucidate the mechanism of channel gating by four histidines that occlude the channel lumen in the closed state. We test two competing hypotheses. In the "shuttle" mechanism, the delta nitrogen atom on the extracellular side of one histidine is protonated by the incoming proton, and, subsequently, the proton on the epsilon nitrogen atom is released on the opposite side. In the "water-wire" mechanism, the gate opens because of electrostatic repulsion between four simultaneously biprotonated histidines. This allows for proton transport along the water wire that penetrates the gate. For each system, composed of the channel embedded in a hydrated phospholipid bilayer, a 1.3-ns trajectory was obtained. It is found that the states involved in the shuttle mechanism, which contain either single-protonated histidines or a mixture of single-protonated histidines plus one biprotonated residue, are stable during the simulations. Furthermore, the orientations and dynamics of water molecules near the gate are conducive to proton transfer. In contrast, the fully biprotonated state is not stable. Additional simulations show that if only two histidines are biprotonated, the channel deforms but the gate remains closed. These results support the shuttle mechanism but not the gate-opening mechanism of proton gating in M-2. C1 NASA, Ames Res Ctr, Biomol & Cellular Modelling Program, Exobiol Branch, Moffett Field, CA 94035 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. RP Pohorille, A (reprint author), NASA, Ames Res Ctr, Biomol & Cellular Modelling Program, Exobiol Branch, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 44 TC 60 Z9 62 U1 1 U2 5 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD JAN PY 2000 VL 78 IS 1 BP 150 EP 163 PN 1 PG 14 WC Biophysics SC Biophysics GA 274NX UT WOS:000084772900015 PM 10620282 ER PT S AU Moore, JP Childers, BA Froggatt, ME Cook, AL Coffey, NC Coen, LJ Diamond, JK Huynh, PT Riley, EM Stover, SK Vipavetz, KG Wells, JE Woodman, KL Armstrong, CD Sirkis, JS Peng, YT AF Moore, JP Childers, BA Froggatt, ME Cook, AL Coffey, NC Coen, LJ Diamond, JK Huynh, PT Riley, EM Stover, SK Vipavetz, KG Wells, JE Woodman, KL Armstrong, CD Sirkis, JS Peng, YT BE Erodogan, T Friebele, EJ Kashyap, R TI An overview of the fiber optic sensing system for hydrogen leak detection in the space shuttle discovery on STS-96 SO BRAGG GRATINGS, PHOTOSENSITIVITY AND POLING IN GLASS WAVEGUIDES SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (BGPP 99) CY SEP 23-25, 1999 CL STUART, FL SP Opt Soc Amer C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Moore, JP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-593-5 J9 OSA TRENDS OPT PHOTO PY 2000 VL 33 BP 43 EP 44 PG 2 WC Optics SC Optics GA BT55Q UT WOS:000173315800010 ER PT S AU Froggatt, M Erdogan, T Moore, J Shenk, S AF Froggatt, M Erdogan, T Moore, J Shenk, S BE Erodogan, T Friebele, EJ Kashyap, R TI Optical frequency domain characterization (OFDC) of dispersion in optical fiber Bragg gratings SO BRAGG GRATINGS, PHOTOSENSITIVITY AND POLING IN GLASS WAVEGUIDES SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (BGPP 99) CY SEP 23-25, 1999 CL STUART, FL SP Opt Soc Amer C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Froggatt, M (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-593-5 J9 OSA TRENDS OPT PHOTO PY 2000 VL 33 BP 176 EP 178 PG 3 WC Optics SC Optics GA BT55Q UT WOS:000173315800036 ER PT S AU Froggatt, M Erdogan, T AF Froggatt, M Erdogan, T BE Erodogan, T Friebele, EJ Kashyap, R TI Measurement of grating chirp using the second harmonic grating. SO BRAGG GRATINGS, PHOTOSENSITIVITY AND POLING IN GLASS WAVEGUIDES SE OSA TRENDS IN OPTICS AND PHOTONICS LA English DT Proceedings Paper CT Topical Meeting on Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides (BGPP 99) CY SEP 23-25, 1999 CL STUART, FL SP Opt Soc Amer ID FIBER C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Froggatt, M (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMERICA PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-5695 BN 1-55752-593-5 J9 OSA TRENDS OPT PHOTO PY 2000 VL 33 BP 195 EP 197 PG 3 WC Optics SC Optics GA BT55Q UT WOS:000173315800042 ER PT B AU Nicholson, LM Whitley, KS Gates, TS AF Nicholson, LM Whitley, KS Gates, TS BE Loud, S Karbhari, V Adams, DO Strong, AB TI Molecular weight effects on the viscoelastic response of a polyimide SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE polyimides; ageing; mechanical properties ID AMORPHOUS POLYMERS; FREE-VOLUME; TERM CREEP; COMPOSITES; DEPENDENCE; FRACTURE; TENSION; MODEL AB The effect of molecular weight on the viscoelastic performance of an advanced polymer (LaRC(TM)-SI) was investigated through the use of creep compliance tests. Testing consisted of short-term isothermal creep and recovery with the creep segments performed under constant load. The tests were conducted at three temperatures below the glass transition temperature of each material with different molecular weight. Through the use of time-aging-time superposition procedures, the material constants, material master curves and aging-related parameters were evaluated at each temperature for a given molecular weight. The time-temperature superposition technique helped to describe the effect of temperature on the timescale of the viscoelastic response of each molecular weight. It was shown that the low molecular weight materials have increased creep compliance and creep compliance rate, and are mon sensitive to temperature than the high molecular weight materials. Furthermore, a critical molecular weight transition was observed to occur at a weight-average molecular weight of similar to 25000 g/mol below which, the temperature sensitivity of the time-temperature superposition shift factor increases rapidly. C1 NASA, Langley Res Ctr, Natl Res Council Resident Res Associate, Hampton, VA 23681 USA. RP Nicholson, LM (reprint author), NASA, Langley Res Ctr, Natl Res Council Resident Res Associate, Hampton, VA 23681 USA. NR 29 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 564 EP 578 PG 3 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600054 ER PT B AU Costen, RC AF Costen, RC BE Loud, S Karbhari, V Adams, DO Strong, AB TI Thermal edge-effects model for automated tape placement of thermoplastic composites SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE modeling; automated tape placement; thermal analysis AB Two-dimensional thermal models for automated tape placement (ATP) of thermoplastic composites neglect the diffusive heat transport that occurs between the newly placed tape and the cool substrate beside it. Such lateral transport can cool the tape edges prematurely and weaken the bond. The three-dimensional, steady state, thermal transport equation is solved by the Green's function method for a tape of finite width being placed on an infinitely wide substrate. The isotherm for the glass transition temperature on the weld interface is used to determine the distance inward from the tape edge that is prematurely cooled, called the cooling incursion Deltaa. For the Langley ATP robot, Deltaa = 0.4 mm for a unidirectional lay-up of PEEK/carbon fiber composite, and Deltaa = 1.2 mm for an isotropic lay-up. A formula for Deltaa is developed and applied to a wide range of operating conditions. A surprise finding is that Deltaa need not decrease as the Peclet number Pe becomes very large, where Pe is the dimensionless ratio of inertial to diffusive heat transport. Conformable rollers that increase the consolidation length would also increase Deltaa,unless other changes are made, such as proportionally increasing the material speed. To compensate for premature edge cooling, the thermal input could be extended past the tape edges by the amount Deltaa. This method should help achieve uniform weld strength and crystallinity across the width of the tape. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Costen, RC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 10 TC 0 Z9 0 U1 2 U2 4 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 721 EP 733 PG 5 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600068 ER PT B AU Bar-Cohen, Y Lih, SS AF Bar-Cohen, Y Lih, SS BE Loud, S Karbhari, V Adams, DO Strong, AB TI Progress and challenges to NDE of composites using obliquely insonified ultrasonic waves SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE leaky lamb waves (LLW); NDE; composites; stiffness constants; plate wave modes AB The high stiffness to weight ratio, low electromagnetic reflectance and the ability to embed sensors and actuators have made polymer-matrix fiber-reinforced composites an attractive primary construction material for modem high performance structures. However, the multiple step production process and the inherent non-homogeneity of their brittle matrix make these composites susceptible to the formation of many possible defects throughout their life cycle. Another limiting factor in widespread use of composites is their high cost - composite parts are about an order of magnitude more expensive than metallic parts. In addition, the cost of inspection is about 30% of the total cost of acquiring and operating composite structures. This large portion of the total cost makes the need for the development of effective and efficient inspection tools critical not only to the operation but also to the cost benefit of these materials. Conventional inspection methods are capable of providing limited and mostly qualitative information about the degradation of the material properties and of developing defects in composite materials. In recent years, several NDE methods were developed where the anisotropic nonhomogeneous nature of composites is taken into account. In spite of the theoretical and experimental progress, current methods are continuously faced with challenges to meet the growing complex performance requirements that are posed by industry. The progress and challenges for NDE of composites will be reviewed and discussed in this paper. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 82-105, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 1316 EP 1327 PG 2 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600120 ER PT B AU Chamis, CC Minnetyan, L AF Chamis, CC Minnetyan, L BE Loud, S Karbhari, V Adams, DO Strong, AB TI Computational simulation of aerospace structures fatigue-life SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE composites; fatigue; analyses ID PROGRESSIVE FRACTURE; COMPOSITE AB Fatigue life/durability of composites is evaluated via computational simulation. A computer model is utilized for the assessment of structural response, progressive fracture, and defect/damage tolerance characteristics. Critical locations for damage initiation are identified. Constituent material properties, stress and strain limits are scaled up to the structure level to evaluate the overall damage and its respective propagation. Damage initiation, growth, accumulation, and propagation to fracture due to cyclic fatigue are included in the simulations. Fatigue life results are shown for polymer and metal matrix composites and for metals. Results show the damage progression sequence and the changes in the structural response characteristics during different degradation stages. A procedure is outlined for use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of experimental results with insight for design decisions. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chamis, CC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 1378 EP 1392 PG 5 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600125 ER PT B AU Smith, JG Connell, JW Hergenrother, PM Criss, JM AF Smith, JG Connell, JW Hergenrother, PM Criss, JM BE Loud, S Karbhari, V Adams, DO Strong, AB TI High temperature transfer molding resins SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE resin transfer molding; high temperature polymers; polyimides; phenylethynyl containing imides; composites; carbon fiber composites; oligomeric thermosetting imides ID TERMINAL PHENYLETHYNYL GROUPS; IMIDE OLIGOMERS; COMPOSITE PROPERTIES; POLYIMIDE OLIGOMERS; ADHESIVE; PENDENT; ANHYDRIDES AB As part of an ongoing effort to develop materials for resin transfer molding (RTM) processes to produce high performance/high temperature composite structures, phenylethynyl-containing imides have been under investigation. Many phenylethynyl containing imides were prepared and evaluated for melt flow behavior and for mechanical properties after thermal curing. Several candidates exhibited melt viscosities of 0.1-1.0 Pa.s, excellent melt stability (>4 hours) at 250-290 degreesC, high cured glass transition temperatures, good toughness, and, in general, the appropriate combination of properties required for RTM processes. Concurrent with this work, an injector that was compatible with the high injection temperatures (250-290 degreesC) required for these materials was developed by Radius Engineering and Lockheed Martin. Flat, void free composite panels (approximately 0.09 m(2), 4 plys thick) were initially fabricated and tested. To further demonstrate the technology, a 2.4 m long curved F-frame with excellent wet-out and less than 1% void content was fabricated. The chemistry, physical, and mechanical properties of these resins and the fabrication of a polymer matrix composite F-frame via RTM using one of these resins will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, JG (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 31 TC 0 Z9 0 U1 0 U2 0 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 1584 EP 1597 PG 4 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600143 ER PT B AU Friedman, R Jackson, B Olson, S AF Friedman, R Jackson, B Olson, S BE Loud, S Karbhari, V Adams, DO Strong, AB TI Testing and selection of fire-resistant materials for spacecraft use SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE fire; spacecraft; testing/evaluation ID MICROGRAVITY; COMBUSTION AB Spacecraft fire-safety strategy emphasizes prevention, mostly through the selection of onboard items classified according to their fire resistance. The principal NASA acceptance tests described in this paper assess the flammability of materials and components under "worst-case" normal-gravity conditions of upward flame spread in controlled-oxygen atmospheres. Tests conducted on the ground, however, cannot duplicate the unique fire characteristics in the nonbuoyant low-gravity environment of orbiting spacecraft. Research shows that flammability and fire-spread rates in low gravity are sensitive to forced convection (ventilation flows) and atmospheric-oxygen concentration. These research results are helping to define new material-screening test methods that will better evaluate material performance in spacecraft. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Friedman, R (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 42 TC 0 Z9 0 U1 1 U2 1 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 1685 EP 1699 PG 9 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600151 ER PT B AU Watson, KA Connell, JW AF Watson, KA Connell, JW BE Loud, S Karbhari, V Adams, DO Strong, AB TI Space environmentally stable polyimides and copolyimides SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE low color polyimides; atomic oxygen resistant polymers; phosphine oxide-containing films; polyimides; UV resistant polyimides ID POLY(ARYLENE ETHER HETEROCYCLE)S; OXIDE-CONTAINING POLYIMIDES; OXYGEN PLASMA; FILMS AB Polyimides with a unique combination of properties including low color in thin films, atomic oxygen (AO), ultra-violet (UV) radiation resistance, solubility in organic solvents in the imide form, high glass transition (T-g) temperatures and high thermal stability have been prepared and characterized. The polymers were prepared by reacting a novel aromatic diamine with aromatic dianhydrides in a polar aprotic solvent. The solubility of the polymers in the imide form as well as the color density of thin films were dependent upon the chemical structure of the dianhydride. Several thin films (25-50 mum thick) prepared by solution casting of amide acid or imide solutions exhibited very low color and high optical transparency (similar to 90%) as determined by UV/visible spectroscopy. The polymers exhibited T(g)s >200 degreesC depending upon the structure of the dianhydride and temperatures of 5% weight loss similar to 500 degreesC in air as determined by dynamic thermogravimetric analysis. Thin films coated with silver/inconel were exposed to a high fluence of AO and 1000 equivalent solar hours of UV radiation. The effects of these exposures on optical properties were minor. These space environmentally durable polymers are potentially useful in a variety of applications on spacecraft such as thin film membranes on antennas, second-surface miners, thermal/optical coatings and multi-layer thermal insulation (MLI) blanket materials. The chemistry, physical and mechanical properties of the polymers as well as their responses to AO and UV exposure will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Watson, KA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 13 TC 0 Z9 0 U1 2 U2 2 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 1907 EP 1920 PG 4 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600172 ER PT B AU Hodge, AJ Kaul, RK McMahon, WM Reinarts, T AF Hodge, AJ Kaul, RK McMahon, WM Reinarts, T BE Loud, S Karbhari, V Adams, DO Strong, AB TI Sandwich composite, syntactic foam core based application for space structures SO BRIDGING THE CENTURIES WITH SAMPE'S MATERIALS AND PROCESSES TECHNOLOGY, VOL 45, BOOKS 1 AND 2 LA English DT Proceedings Paper CT 45th International SAMPE Symposium and Exhibition on Bridging the Centuries with SAMPEs Materials and Processes Technology CY MAY 21-25, 2000 CL LONG BEACH, CA SP Soc Advancement Mat & Proc Engn DE composites; high temperature mechanical testing; aerothermal testing AB The current Solid Rocket Booster (SRB) launch vehicle has several metal based components that require a Thermal Protective System (TPS) be applied to the exterior surface to ensure its structural integrity and to protect the interior hardware from aerodynamic heating. TPS materials have distinct disadvantages associated with their use. One disadvantage to the application of TPS is that it can act as a debris source to the Space Shuttle Orbiter during flight and it also adds weight to the system without directly contributing any structural strength. One of the specific areas examined under this program was to replace a metal/TPS system with polymer based composites. A polymer matrix based sandwich composite was developed which had both structural and insulative properties to meet the high aerodynamic structural and heating load survival requirements. The SRB Nose Cap was selected as a candidate for this application. The sandwich system being qualified for this application is a carbon/epoxy outer and inner skin with a high strength-low thermal conductivity syntactic foam core. C1 NASA, George C Marshall Space Flight Ctr, ED34, Huntsville, AL 35812 USA. RP Hodge, AJ (reprint author), NASA, George C Marshall Space Flight Ctr, ED34, Huntsville, AL 35812 USA. NR 3 TC 0 Z9 0 U1 1 U2 3 PU SOC ADVANCEMENT MATERIAL & PROCESS ENGINEERING PI COVINA PA 1161 PARKVIEW DR,, COVINA, CA 91724-3748 USA BN 0-938994-86-7 PY 2000 BP 2293 EP 2304 PG 6 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BQ88N UT WOS:000089937600207 ER PT S AU Dotani, T Asai, K Ebisawa, K Greiner, J AF Dotani, T Asai, K Ebisawa, K Greiner, J BE Makishima, K Piro, L Takahashi, T TI ASCA and ROSAT observations of supersoft X-ray sources SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID WHITE-DWARF MODELS; EVOLUTION AB Energy spectra of four luminous supersoft X-ray sources (SSS) are investigated combining the ASCA SIS and the ROSAT PSPC data. We found that the energy spectra of the SSS are commonly reproduced by a blackbody continuum model superposed with sharp edge-like structures. Despite of several years intervals between the ASCA, and ROSAT observations, differences of the best-fit parameters are found to be small, This indicates that X-ray emissions from these foils SSS are rather stable. The blackbody temperature and the edge energies show large differences among the sources, which may reflect differences in the white dwarf mass. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. RP Dotani, T (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshino Dai, Sagamihara, Kanagawa 2298510, Japan. NR 11 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 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 375 EP 378 DI 10.1016/S0273-1177(99)00761-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000004 ER PT S AU Rubin, BC Barret, D Harmon, BA Matsuoka, M Mihara, T Negoro, H Paciesas, WS Tavani, M AF Rubin, BC Barret, D Harmon, BA Matsuoka, M Mihara, T Negoro, H Paciesas, WS Tavani, M BE Makishima, K Piro, L Takahashi, T TI The broad band x-ray spectrum of Aquila X-1 during a mini-outburst SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res AB Here we report an analysis of the broad band x-ray spectrum of the x-ray burst source Aquila X-l during a "mini-outburst" (peak flux < 0.25 mCrab) in which hard x-rays were detected out to at least 100 keV. We find that a joint, quasi-simultaneous ASCA-BATSE spectrum may be consistent either with a black body plus a broken power law, or with a Comptonization model. Broad band observations like this are essential for revealing the fundamental physics issues involved. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Riken Inst, Cosm Radiat Lab, Wako, Saitama 3510198, Japan. CNRS, CESR, Toulouse, France. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Columbia Univ, New York, NY USA. RP Rubin, BC (reprint author), Riken Inst, Cosm Radiat Lab, Wako, Saitama 3510198, Japan. RI Mihara, Tatehiro/C-5536-2017; OI Mihara, Tatehiro/0000-0002-6337-7943; Tavani, Marco/0000-0003-2893-1459 NR 16 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 379 EP 382 DI 10.1016/S0273-1177(99)00762-0 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000005 ER PT S AU Barret, D Olive, JF Boirin, L Grindlay, JE Swank, JH Smale, AP AF Barret, D Olive, JF Boirin, L Grindlay, JE Swank, JH Smale, AP BE Makishima, K Piro, L Takahashi, T TI No high frequency quasi-periodic oscillations from the X-ray burster 1E1724-3045 SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID DISCOVERY AB The type I X-ray burster 1E1724-3045 located in the globular cluster Terzan 2 was observed by the Rossi X-ray Timing Explorer (RXTE) while it was in a Island state, displaying both intense flickering and a hard Comptonized spectrum. No statistically significant High Frequency Quasi-Periodic Oscillations (HFQPOs) were detected. A 3 sigma upper limit on the fractional Root Mean Squared (RMS) of similar to 2.5% has thus been derived in the 5-30 keV band. Attenuation of the QPO signal in a scattering corona of optical depth similar to 3 as inferred from the spectral analysis could provide an explanation for the non-detection of HFQPOs from 1E1724-3045. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 CNRS, UPS, CESR, F-31028 Toulouse, France. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barret, D (reprint author), CNRS, UPS, CESR, 9 Ave Colonel Roche, F-31028 Toulouse, France. RI Swank, Jean/F-2693-2012 NR 11 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 383 EP 386 DI 10.1016/S0273-1177(99)00763-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000006 ER PT S AU Nishiuchi, M Koyama, K Maeda, Y Dotani, T Asai, K Ueda, Y Mitsuda, K Nagase, F Inoue, H Kouveliotou, C AF Nishiuchi, M Koyama, K Maeda, Y Dotani, T Asai, K Ueda, Y Mitsuda, K Nagase, F Inoue, H Kouveliotou, C BE Makishima, K Piro, L Takahashi, T TI The ASCA observation of GRO J1744-28 SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID RAY AB The ASCA results of the bursting X-ray pulsar GRO J1744-28 are reported. The observations were made twice, in February 1996 and March 1997. We detected 12 and 17 Type II bursts during the two observations, with mean bursting intervals of about 27 min and 37 min. Each burst is followed by an intensity dip with the depleted flux depending on the burst fluence. The energy spectra are approximated by an absorbed power law with additional structure around 6-7 keV, which is most probably due to iron and maybe reproduced by the disk line model with additional broadening mechanism. The absorption column is constant ((5 - 6) x 10(22) cm(-2)), independent of the observation dates and emission phase (persistent, burst and dip). This means the source may be actually located near the galactic center (8.5kpc). (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Kyoto Univ, Dept Phys, Sakyo Ku, Kyoto 6068502, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Nishiuchi, M (reprint author), Kyoto Univ, Dept Phys, Sakyo Ku, Kitashirakewa Oiwake Cho, Kyoto 6068502, Japan. RI Mitsuda, Kazuhisa/C-2649-2008 NR 11 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 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 391 EP 394 DI 10.1016/S0273-1177(99)00765-6 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000008 ER PT S AU Ozaki, M Corbet, RHD Marshall, FE Lochner, JC AF Ozaki, M Corbet, RHD Marshall, FE Lochner, JC BE Makishima, K Piro, L Takahashi, T TI ASCA observations of two new X-ray pulsars near SMC X-3 SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res AB ASCA carried out target of opportunity observations centered on the position of SMC;X-3 following the report of a detection of emission from SMC X-3 with RXTE. However, no source was detected at the position of SMC X-3 itself, instead two new pulsars in the SMC were found within the ASCA field of view with periods of 46.6 and 91.1 sec. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Ozaki, M (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan. RI Ozaki, Masanobu/K-1165-2013; Perrodin, Delphine/L-1916-2016 OI Perrodin, Delphine/0000-0002-1806-2483 NR 8 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 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 425 EP 428 DI 10.1016/S0273-1177(99)00772-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000015 ER PT S AU Kotani, T Ebisawa, K Inoue, H Kawai, N Matsuoka, M Nagase, F Robinson, CR Takeshima, T Ueda, Y Yamaoka, K Yoshida, A AF Kotani, T Ebisawa, K Inoue, H Kawai, N Matsuoka, M Nagase, F Robinson, CR Takeshima, T Ueda, Y Yamaoka, K Yoshida, A BE Makishima, K Piro, L Takahashi, T TI Discovery of iron-K absorption lines from the transient jets GRS 1915+105 and GRO J1655-40 SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID SUPERLUMINAL SOURCE AB K-line absorption features of highly ionized iron were discovered in X-ray spectra of super-luminal transient jets GRS 1915+105 and GRO J1655-40 with ASCA. The absorption lines were identified as Fe XXV K alpha, Fe XXVI K alpha and Ni XXVII K alpha resonance lines with equivalent width of 20-50 eV. They are evidence of highly ionized plasma in anisotropic configuration or in anisotropic illumination in the vicinity of the source. We adopted models of photoionized plasma with a cylindrical geometry, and estimated physical parameters such as density, dimension, solid angle from the source, temperature and xi-parameter. It is suggested that the kinetic temperature of resonant scattering atoms is very high, at least 100 keV. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 RIKEN, Cosm Radiat Lab, Wako, Saitama 3510198, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ISAS, High Energy Astrophys Div, Sagamihara, Kanagawa 2298501, Japan. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Kotani, T (reprint author), RIKEN, Cosm Radiat Lab, Hirosawa 2-1, Wako, Saitama 3510198, Japan. NR 6 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2000 VL 25 IS 3-4 BP 445 EP 448 DI 10.1016/S0273-1177(99)00777-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000020 ER PT S AU Matsumoto, R Valinia, A Tajima, T Makishima, K Shibata, K AF Matsumoto, R Valinia, A Tajima, T Makishima, K Shibata, K BE Makishima, K Piro, L Takahashi, T TI Formation of localized strongly magnetized regions in galaxies and clusters of galaxies SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID 3-DIMENSIONAL MAGNETOHYDRODYNAMIC SIMULATIONS; ACCRETION DISKS; GALACTIC RIDGE; SOLAR-FLARE; SHEAR-FLOW; RECONNECTION; INSTABILITY; FIELDS AB Through three-dimensional global magnetohydrodynamic (MHD) simulations, we show that localized strongly magnetized regions are created in galaxies and clusters of galaxies. We carried out simulations of (1) dynamical evolution of magnetic fields in differentially rotating disks and (2) amplification of magnetic fields through the rotation and motions of individual galaxies in clusters of galaxies. In either case, we find that even though the mean magnetic energy is smaller than the thermal energy (beta = P-gas/P-mag greater than or equal to 1), magnetic pressure dominated, low-beta (beta less than or equal to 1) filaments are created. Magnetic reconnection taking place in the strongly magnetized regions heats the plasma typically up to 10 keV. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Chiba Univ, Fac Sci, Dept Phys, Inage Ku, Chiba 2638522, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Texas, Austin, TX 78712 USA. Univ Tokyo, Dept Phys, Tokyo 1130033, Japan. Natl Astron Observ, Tokyo 1818588, Japan. RP Matsumoto, R (reprint author), Chiba Univ, Fac Sci, Dept Phys, Inage Ku, Chiba 2638522, Japan. NR 18 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 499 EP 504 DI 10.1016/S0273-1177(99)00787-5 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000030 ER PT S AU Kitamoto, S Tanaka, S Suzuki, T Torii, K Corcoran, MF Waldron, W AF Kitamoto, S Tanaka, S Suzuki, T Torii, K Corcoran, MF Waldron, W BE Makishima, K Piro, L Takahashi, T TI Six early type stars observed by ASCA SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID X-RAY-EMISSION; HOT STARS; WINDS; MODEL AB Chemical abundances of six OB stars are determined by the ASCA data. Low metal abundances are derived from a simple optically thin plasma model. Multi-temperature models also derive low metal abundances. We interpret that the plasmas are not optically thin for the resonance lines and the line intensities are suppressed by the absorption. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Osaka Univ, Grad Sch Sci, Dept Earth & Space Sci, Toyonaka, Osaka 560, Japan. Japan Sci & Technol Corp, JST, CREST, Kawaguchi, Saitama 332, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Appl Res Corp, Landover, MD 20785 USA. RP Kitamoto, S (reprint author), Osaka Univ, Grad Sch Sci, Dept Earth & Space Sci, 1-1 Machikaneyama Cho, Toyonaka, Osaka 560, Japan. NR 12 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 527 EP 530 DI 10.1016/S0273-1177(99)00793-0 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000036 ER PT S AU Thompson, DJ AF Thompson, DJ BE Makishima, K Piro, L Takahashi, T TI High energy emission from active pulsars SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID GAMMA-RAY PULSARS; X-RAY; PSR J0437-4715; SGR-1806-20; NEBULA; SHAPE AB Nonthermal emission is seen from some pulsars across much of the electromagnetic spectrum, implying acceleration of particles to high energies. The power for this process usually comes from the rotation of the magnetized neutron star. The luminosity of these pulsars peaks in the X-ray to gamma-ray bands. The light curves for some of these pulsars suggest particle acceleration and radiation from a hollow surface above one magnetic pole of the star. Multiwavelength observations have been used to construct and test models of high-energy pulsar radiation. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM djt@egret.gsfc.nasa.gov RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 31 TC 14 Z9 14 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2000 VL 25 IS 3-4 BP 659 EP 668 DI 10.1016/S0273-1177(99)00818-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000061 ER PT S AU Torii, K Kinugasa, K Asanuma, T Toneri, T Tsunemi, H Dotani, T Mitsuda, K Gotthelf, EV Petre, R AF Torii, K Kinugasa, K Asanuma, T Toneri, T Tsunemi, H Dotani, T Mitsuda, K Gotthelf, EV Petre, R BE Makishima, K Piro, L Takahashi, T TI ASCA studies of young pulsars and SNRs SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID X-RAY SOURCE; ABSORPTION-MEASUREMENTS; REMNANT G11.2-0.3; SUPERNOVA; RADIO; DISCOVERY; RCW-103 AB During the course of our X-ray studies of composite supernova remnants, we have discovered two young pulsars, The 65 ms pulsar, AX J1811.5-1926, is found to be associated with the central X-ray emission from the candidate of the historical SNR G11.2-0.3; and the 69 ms pulsar near the SNR RCW 103 is identified with a previously reported GINGA pulsator. Here, we present an observational summary of these two pulsars. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Natl Space Dev Agcy Japan, Space Utilizat Res Program, Tsukuba Space Ctr, Tsukuba, Ibaraki 3058505, Japan. Gunma Astron Observ, Maebashi, Gumma 3710847, Japan. Osaka Univ, Dept Earth & Space Sci, Grad Sch Sci, Toyonaka, Osaka 5600043, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Torii, K (reprint author), Natl Space Dev Agcy Japan, Space Utilizat Res Program, Tsukuba Space Ctr, 2-1-1 Sengen, Tsukuba, Ibaraki 3058505, Japan. RI Mitsuda, Kazuhisa/C-2649-2008 NR 22 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 669 EP 672 DI 10.1016/S0273-1177(99)00819-4 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000062 ER PT S AU Durouchoux, P Sood, R Oka, T Segers, M Safi-Harb, S Vilhu, O Huovelin, J Thresher, D Corbel, S O'Neill, P AF Durouchoux, P Sood, R Oka, T Segers, M Safi-Harb, S Vilhu, O Huovelin, J Thresher, D Corbel, S O'Neill, P BE Makishima, K Piro, L Takahashi, T TI Jet interaction of SS 433 with the ambient medium SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID SS433; SYSTEM; SS-433; ROSAT; RADIO AB SS 433 is a bright X-ray binary with two sided jets moving at 0.26 c. It is located at the center of the supernova remnant W50, suggesting that SS 433 is associated with W50. A large molecular cloud also surrounds the SS 433/W50 system. Recent observations with ROSAT and ASCA have shown X-ray hot spots interpreted as SS 433 jets interacting with the ambient interstellar medium. To verify this hypothesis, we have performed observations of the molecular cloud around SS 433 in the J = 1-0 and J = 2-1 lines of CO transitions along and perpendicular to the jet axis and have found two clouds with velocities of 32 km/s and 50 km/s respectively. Due to a strong correlation between the 50 km/s map and the X-ray hot spots, we conclude that SS 433 is inside or at the edge of the 50 km/s molecular cloud. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 CE Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ New S Wales, Univ Coll, ADFA, Sch Phys, Canberra, ACT 2600, Australia. RIKEN, Wako, Saitama 35101, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Helsinki, Observ Helsinki, FIN-00014 Helsinki, Finland. Ecole Cent Paris, F-92295 Chatenay Malabry, France. RP Durouchoux, P (reprint author), CE Saclay, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. NR 10 TC 4 Z9 4 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 703 EP 708 DI 10.1016/S0273-1177(99)00826-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000069 ER PT S AU Kubo, H Takahashi, T Madejski, G Tashiro, M Makino, F Inoue, S Takahara, F AF Kubo, H Takahashi, T Madejski, G Tashiro, M Makino, F Inoue, S Takahara, F BE Makishima, K Piro, L Takahashi, T TI ASCA observations of blazars and multiband analysis SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID RAY; EMISSION; FLARE; JETS AB We present data for 18 blazars observed with ASCA, half of which were also observed contemporaneously with EGRET as parts of multi-wavelength campaigns. The ASCA X-ray spectra of High-energy peaked BL Lacs (HBLs) are soft, and they form the highest energy tail of the low energy (synchrotron) component. The X-ray spectra of the quasar-hosted blazars (QHBs) are hard and consistent with the lowest energy end of the high energy (Compton) component. For Low-energy peaked BL Lacs (LBLs), the X-ray spectra are intermediate. We find that the radiation process responsible for the HE peak for HBLs can be explained solely by Synchrotron-Self-Compton (SSC) emission. For many QHBs, on the other hand, the gamma-rays cannot be solely due to the SSC mechanism. We consider an alternative scenario for QHBs where the SSC component dominates in the X-ray band, but it is below the observed gamma-ray spectrum. We infer the magnetic field B to be 0.1 - 1 Gauss, and Lorentz factors gamma(b) of electrons radiating at the peak of the nu F(nu) spectrum of similar to 10(3) for QHBs. This is much lower than gamma(b) similar to 10(5) for HBLs. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Inst Phys & Chem Res, RIKEN, Wako, Saitama 3510198, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Tokyo Metropolitan Univ, Hachioji, Tokyo 1920397, Japan. Osaka Univ, Dept Earth & Space Sci, Grad Sch Sci, Toyonaka, Osaka 5600043, Japan. RP Kubo, H (reprint author), Inst Phys & Chem Res, RIKEN, 2-1 Hirosawa, Wako, Saitama 3510198, Japan. RI Tashiro, Makoto/J-4562-2012 NR 22 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 733 EP 736 DI 10.1016/S0273-1177(99)00831-5 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000074 ER PT S AU Kataoka, J Mattox, JR Quinn, J Kubo, H Makino, F Takahashi, T Inoue, S Hartmann, RC Madejski, GM Sreekumar, P Wagner, SJ AF Kataoka, J Mattox, JR Quinn, J Kubo, H Makino, F Takahashi, T Inoue, S Hartmann, RC Madejski, GM Sreekumar, P Wagner, SJ BE Makishima, K Piro, L Takahashi, T TI A study of high energy emission from the TeV blazar Mrk 501 during multiwavelength observations in 1996 SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID GAMMA-RAY EMISSION; RADIATION; MODEL AB We present the results of a multiwavelength campaign for Mrk 501 performed in March 1996 with ASCA. EGRET, Whipple, and optical telescopes. We report here for the first time the detection of GeV gamma-ray flux from Mrk 501 with EGRET with 3.5 sigma significance (E > 100 MeV). Higher flux was also observed in April/May 1996, with 4.0 sigma for E > 100 MeV, and 5.2 sigma for E > 500 MeV. We find that the multiband spectrum in March 1996 is consistent with that calculated from a one-zone SSC model, except for the extremely 'flat' TeV spectrum. We show that this flat spectrum cannot be explained by either 2nd order Comptonization or the contribution of the 'seed' IR photons from the host galaxy. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Boston Univ, Dept Astron, Boston, MA 02215 USA. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Tokyo Metropolitan Univ, Dept Phys, Hachioji, Tokyo 1920397, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. RP Kataoka, J (reprint author), Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan. NR 14 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 737 EP 740 DI 10.1016/S0273-1177(99)00832-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000075 ER PT S AU Cappi, M Bassani, L Malaguti, G Palumbo, GGC Dadina, M Comastri, A Di Cocco, G Blanco, P Dal Fiume, D Fabian, A Frontera, F Guainazzi, M Maccacaro, T Maiolino, R Matt, G Piro, L Trifoglio, M Zhang, N AF Cappi, M Bassani, L Malaguti, G Palumbo, GGC Dadina, M Comastri, A Di Cocco, G Blanco, P Dal Fiume, D Fabian, A Frontera, F Guainazzi, M Maccacaro, T Maiolino, R Matt, G Piro, L Trifoglio, M Zhang, N BE Makishima, K Piro, L Takahashi, T TI A qualitative test of a unified model of Seyfert galaxies with BeppoSAX SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID ACTIVE GALACTIC NUCLEI; RAY; REFLECTION; MATTER AB The broad band 0.1-200 keV spectra of a sample of 5 Seyfert 2 galaxies (NGC 7172, Mkn 3, NGC 2110, NGC 4507 and NGC 7674) have been measured within the first year of the BeppoSAX Core program. All sources have been detected up to similar to 100 keV and their spectral characteristics derived with good accuracy. Although the results obtained from the detailed analysis of individual sources indicate some "source-by-source" differences, we show in the following that all spectra are consistent, at least qualitatively, with what expected from a "0(th)-order" version of unified models. Indeed, a simple test on these data indicates that these Seyfert 2 galaxies are on average intrinsically very similar to Seyfert 1 galaxies (i.e., steep at E greater than or similar to 10 keV) and that the main difference can be ascribed to a different amount of absorbing matter along the line of sight (i.e. different inclinations of our line of sight with respect to a putative molecular torus or different thicknesses of the tori). (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 CNR, Ist Tesre, I-40129 Bologna, Italy. Univ Bologna, Dipartimento Astron, I-40126 Bologna, Italy. BeppoSAX SDC, ASI, I-00131 Rome, Italy. Osservatorio Astron Bologna, Bologna, Italy. Univ Calif San Diego, San Diego, CA 92103 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy. European Space Agcy, SCD, Estec, Div Astrophys, NL-2200 AG Noordwijk, Netherlands. Osservatorio Astron Brera, I-20121 Milan, Italy. Osservatorio Astrofis Arcetri, I-15015 Florence, Italy. Univ Roma III, Dipartimento Fis, I-00146 Rome, Italy. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Cappi, M (reprint author), CNR, Ist Tesre, I-40129 Bologna, Italy. RI Cappi, Massimo/F-4813-2015; Trifoglio, Massimo/F-5302-2015; Comastri, Andrea/O-9543-2015; OI Trifoglio, Massimo/0000-0002-2505-3630; Comastri, Andrea/0000-0003-3451-9970; Cappi, Massimo/0000-0001-6966-8920; Dadina, Mauro/0000-0002-7858-7564; Bassani, Loredana/0000-0003-4858-6963 NR 14 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 815 EP 818 DI 10.1016/S0273-1177(99)00846-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000089 ER PT S AU Yoshita, K Tsunemi, H Hiraga, J Gendreau, KC Bautz, MW AF Yoshita, K Tsunemi, H Hiraga, J Gendreau, KC Bautz, MW BE Makishima, K Piro, L Takahashi, T TI Direct measurement of the charge cloud size in SISCCDs SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID ASCA SATELLITE; COUPLED-DEVICE; RAY; EFFICIENCY; PIXEL; CCD AB We report here the method to measure the primary charge cloud size generated by X-ray photons in the CCD, If the incident X ray is photo-absorbed near the pixel boundary, the primary charge cloud splits into 2-4 pixels. We calculated the center of gravity of the split event weighted by the split charge. We found that the center of gravity is well-correlated with the X-ray interaction position. We analyzed the charge cloud size assuming either the Gaussian shape or the rectangular shape. From the analysis of the data using the model for the charge cloud shape, we measured a charge cloud size of 1 similar to 2 mu m for X rays of Y-L (1.9 keV), Ag-L (3.0 keV) and Ti-K (4.5keV). We also notice that we can determine the X-ray interaction position of the split event with an accuracy better than 1/10 of the pixel size. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Osaka Univ, Dept Earth & Space Sci, Toyonaka, Osaka 5600043, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, CSR, Cambridge, MA 02139 USA. RP Yoshita, K (reprint author), Osaka Univ, Dept Earth & Space Sci, 1-1 Machikaneyama Cho, Toyonaka, Osaka 5600043, Japan. RI PIRO, LUIGI/E-4954-2013 OI PIRO, LUIGI/0000-0003-4159-3984 NR 5 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 889 EP 892 DI 10.1016/S0273-1177(99)00861-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000104 ER PT S AU Kamae, T Ohsugi, T Thompson, DJ Watanabe, K AF Kamae, T Ohsugi, T Thompson, DJ Watanabe, K BE Makishima, K Piro, L Takahashi, T TI Studying the high-energy gamma-ray sky with GLAST SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID EGRET OBSERVATIONS AB Building on the success of the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the Gamma-ray Large Area Space Telescope (GLAST) will make a major step in the study of such subjects as blazars, gamma-ray bursts, the search for dark matter, supernova remnants, pulsars, diffuse radiation, and unidentified high-energy sources. The instrument will be built on new and mature detector technologies such as silicon strip detectors, low-power low-noise LSI, and a multilevel data acquisition system. GLAST is in the research and development phase, and one full tower (of 25 total) is now being built in collaborating institutes. The prototype tower will be tested thoroughly at SLAG in the fall of 1999. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo, Japan. Hiroshima Univ, Dept Phys, Hiroshima 730, Japan. NASA, Goddard Space Flight Ctr, LHEA, USRA, Greenbelt, MD 20771 USA. RP Kamae, T (reprint author), Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo, Japan. EM kamae@phys.s.u-tokyo.ac.jp; ohsugi@hirax3.hepl.hiroshima-u.ac.jp; djt@egret.gsfc.nasa.gov; watanabe@grossc.gsfc.nasa.gov RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 12 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2000 VL 25 IS 3-4 BP 905 EP 910 DI 10.1016/S0273-1177(99)00865-0 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000108 ER PT S AU Ogasaka, Y Yamashita, K Serlemitsos, PJ Tueller, J Barthelmy, SD Chan, KW Furuzawa, A Haga, K Kunieda, H Nakajo, N Nakamura, N Namba, Y Okajima, T Soong, Y Stahl, CM Takata, H Tamura, K Tawara, Y AF Ogasaka, Y Yamashita, K Serlemitsos, PJ Tueller, J Barthelmy, SD Chan, KW Furuzawa, A Haga, K Kunieda, H Nakajo, N Nakamura, N Namba, Y Okajima, T Soong, Y Stahl, CM Takata, H Tamura, K Tawara, Y BE Makishima, K Piro, L Takahashi, T TI Hard X-ray imaging observations: Science and Technology SO BROAD BAND X-RAY SPECTRA OF COSMIC SOURCES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 1 Symposium of COSPAR Scientific Commission E held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Int Astronom Union, Inst Space & Astronaut Sci, Tata Inst Fdn Res, Comm Space Res ID TELESCOPE AB High sensitivity hard X-ray data by means of focusing optics is crucially important to investigate active galaxies and cluster of galaxies. We have developed focusing telescopes with multilayer coatings. The energy band is broadened by multilayers with graded periodic length, so called 'Supermirrors'. We are successful to obtain hard X-ray images in the energy band from 25 to 40 keV with a demonstration model of telescope with 20 mirror shells of supermirrors. The application of supermirrors to the balloon-borne hard X-ray telescope is discussed. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Nagoya Univ, Dept Phys, Chikusa Ku, Nagoya, Aichi 4648602, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Chubu Univ, Dept Mech Engn, Kasugai, Aichi 4878501, Japan. RP Ogasaka, Y (reprint author), Nagoya Univ, Dept Phys, Chikusa Ku, Furocho, Nagoya, Aichi 4648602, Japan. RI Tueller, Jack/D-5334-2012; Barthelmy, Scott/D-2943-2012 NR 4 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 3-4 BP 911 EP 914 DI 10.1016/S0273-1177(99)00866-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP51E UT WOS:000085367000109 ER PT J AU Curry, JA Hobbs, PV King, MD Randall, DA Minnis, P AF Curry, JA Hobbs, PV King, MD Randall, DA Minnis, P TI FIRE arctic clouds experiment SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID REFLECTANCE; ATMOSPHERE; RADIATION; MODEL AB An overview is given of the First ISCCP Regional Experiment Arctic Clouds Experiment that was conducted during April-July 1998. The principal goal of the field experiment was to gather the data needed to examine the impact of arctic clouds on the radiation exchange between the surface, atmosphere, and space, and to study how the surface influences the evolution of boundary layer clouds. The observations will be used to evaluate and improve climate model parameterizations of cloud and radiation processes, satellite remote sensing of cloud and surface characteristics, and understanding of cloud-radiation feedbacks in the Arctic. The experiment utilized four research aircraft that flew over surface-based observational sites in the Arctic Ocean and at Barrow, Alaska. This paper describes the programmatic and scientific objectives of the project, the experimental design (including research platforms and instrumentation), the conditions that were encountered during the field experiment, and some highlights of preliminary observations, modeling, and satellite remote sensing studies. C1 Univ Colorado, Atmospher & Ocean Sci, Boulder, CO 80309 USA. Univ Washington, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Colorado State Univ, Ft Collins, CO 80523 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Atmospher Environm Serv, Downsview, ON, Canada. NOAA, Environm Res Lab, Boulder, CO 80303 USA. Scripps Inst Oceanog, La Jolla, CA USA. Gerber Sci Inc, Reston, VA USA. Desert Res Inst, Reno, NV USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. SPEC Inc, Boulder, CO USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Res Council, Inst Aerosp Res, Ottawa, ON, Canada. Atmospher Environm Serv, Egbert, ON, Canada. Univ Wisconsin, Madison, WI USA. RP Curry, JA (reprint author), Univ Colorado, Atmospher & Ocean Sci, Box 311, Boulder, CO 80309 USA. RI King, Michael/C-7153-2011; Williams, Alastair/P-6946-2014; Intrieri, Janet/D-5608-2015; Randall, David/E-6113-2011; Jakob, Christian/A-1082-2010; Minnis, Patrick/G-1902-2010 OI King, Michael/0000-0003-2645-7298; Williams, Alastair/0000-0002-0568-8487; Randall, David/0000-0001-6935-4112; Jakob, Christian/0000-0002-5012-3207; Minnis, Patrick/0000-0002-4733-6148 NR 13 TC 203 Z9 206 U1 2 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JAN PY 2000 VL 81 IS 1 BP 5 EP 29 DI 10.1175/1520-0477(2000)081<0005:FACE>2.3.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 270GT UT WOS:000084527700001 ER PT J AU Chen, TCM Schubert, S AF Chen, TCM Schubert, S TI Aliasing of the semidiurnal cycle in the depiction of global atmospheric circulation SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material ID EAST-WEST CIRCULATIONS; CLIMATE; SIMULATION; MODEL; TIDES C1 Iowa State Univ, Dept Geol & Atmospher Sci, Atmospher Sci Program, Ames, IA 50011 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Chen, TCM (reprint author), Iowa State Univ, Dept Geol & Atmospher Sci, Atmospher Sci Program, Ames, IA 50011 USA. NR 26 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD JAN PY 2000 VL 81 IS 1 BP 95 EP 100 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 270GT UT WOS:000084527700006 ER PT J AU Cullings, K AF Cullings, K TI Reassessment of phylogenetic relationships of some members of the Monotropoideae based on partial 28S ribosomal RNA gene sequencing SO CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE LA English DT Editorial Material ID ERICACEAE; ORIGIN C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cullings, K (reprint author), NASA, Ames Res Ctr, MS-239-4, Moffett Field, CA 94035 USA. NR 7 TC 6 Z9 6 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4026 J9 CAN J BOT JI Can. J. Bot.-Rev. Can. Bot. PD JAN PY 2000 VL 78 IS 1 BP 1 EP 2 PG 2 WC Plant Sciences SC Plant Sciences GA 292VT UT WOS:000085816400001 ER PT J AU Clowdsley, MS Heinbockel, JH Kaneko, H Wilson, JW Singleterry, RC Shinn, JL AF Clowdsley, MS Heinbockel, JH Kaneko, H Wilson, JW Singleterry, RC Shinn, JL TI A comparison of the multigroup and collocation methods for solving the low-energy neutron Boltzmann equation SO CANADIAN JOURNAL OF PHYSICS LA English DT Article AB A low-energy neutron transport algorithm for use in space-radiation protection is developed. The algorithm is based upon a multiple energy group analysis of the straight ahead Boltzmann equation utilizing a mean value theorem for integrals. The algorithm developed is then verified by using a collocation method solution on the same straight ahead Boltzmann equation. This algorithm was then coupled to the existing NASA Langley HZETRN (high charge and energy transport) code through the evaporation source term. Evaluation of the neutron fluence generated by the February 23, 1956 solar particle event for an aluminum-water shield-target configuration is then compared with the LAHET Monte Carlo calculation for the same shield-target configuration. The algorithm developed showed a great improvement in results over the unmodified HZETRN solution. A bidirectional modification of the evaporation source produced further improvement of the fluence. C1 Old Dominion Univ, Dept Math, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Clowdsley, MS (reprint author), Old Dominion Univ, Dept Math, Norfolk, VA 23529 USA. NR 8 TC 13 Z9 13 U1 0 U2 0 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD JAN PY 2000 VL 78 IS 1 BP 45 EP 56 DI 10.1139/cjp-78-1-45 PG 12 WC Physics, Multidisciplinary SC Physics GA 305KB UT WOS:000086537700005 PM 11543222 ER PT J AU Baker, JD Donohue, MJ AF Baker, JD Donohue, MJ TI Ontogeny of swimming and diving in northern fur seal (Callorhinus ursinus) pups SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID ARCTOCEPHALUS-GAZELLA PUPS; PHOCA-GROENLANDICA; HARP SEAL; BEHAVIOR; GROWTH; ENERGETICS; SURVIVAL; PATTERNS; HISPIDA; WATER AB Time spent in the water and diving behavior of northern fur seal (Callorhinus ursinus) pups were monitored between birth and weaning at St. Paul Island, Alaska. The median age when pups began swimming was 26 days, but prior to 40 days of age they spent virtually all their time on shore and only rarely took brief (15-20 min) swims. Pups began spending substantial time in the water at approximately 40-50 days of age, coinciding both with the early growth of insulating underfur and a seasonal peak in sea surface temperature. This suggests that pups had earlier been constrained to remain on shore by their undeveloped thermoregulatory capabilities. Time in the water increased up to approximately 100 days of age, when molted pups spent about 35% of their time in the water and swim bouts were several hours in duration. Moreover, the presence of a pup's mother on shore, photoperiod, and precipitation also influenced the amount of time pups spent in the water. Pups (mean age = 100 days) dove to very shallow depths (mean = 3 m) for short durations (mean = 11 s). Because pups did not gain mass unless suckled by their mothers, it is unlikely that they fed extensively while diving prior to migration. The pattern of development of swimming and diving in northern fur seals is intermediate between typical phocid and otariid patterns, as is the maternal strategy. C1 NOAA, Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Seattle, WA 98115 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. RP Baker, JD (reprint author), Natl Marine Fisheries Serv, 2570 Dole St, Honolulu, HI 96822 USA. NR 48 TC 42 Z9 43 U1 2 U2 11 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD JAN PY 2000 VL 78 IS 1 BP 100 EP 109 DI 10.1139/cjz-78-1-100 PG 10 WC Zoology SC Zoology GA 290QD UT WOS:000085686400009 ER PT J AU Roden, CL Mullin, KD AF Roden, CL Mullin, KD TI Sightings of Cetaceans in the northern Caribbean Sea and adjacent waters, winter 1995 SO CARIBBEAN JOURNAL OF SCIENCE LA English DT Article ID WHALE MEGAPTERA-NOVAEANGLIAE; EASTERN TROPICAL PACIFIC; ABUNDANCE; DOLPHINS; OCEAN AB A multi-objective research cruise was conducted in the northern Caribbean Sea and the adjacent Atlantic Ocean from 29 January through 8 March 1995. One aspect of the cruise was to determine the feasibility of using ship-based line-transect survey methods to estimate the abundance of cetaceans in waters of Puerto Rico and the U.S. Virgin Islands. Cetacean surveys were also conducted during daylight between ichthyoplankton sampling stations in the Atlantic Ocean east of the Virgin islands, while in transit, and around Pedro Bank, Jamaica. Cetaceans were sighted 65 times (including three two-species sightings) and 4275 transect km were surveyed. At least nine cetacean species were identified, including (number of groups sighted) humpback whale (Megaptera novaeangliae), 12; minke whale (Balaenoptera acutorostrata), 1; sperm whale (Physeter macrocephalus), 8; Mesoplodon spp., 2; shortfin pilot whale (Globicephala macrorhynchus), 9; bottlenose dolphin (Tursiops truncatus), 3; Atlantic spotted dolphin (Stenella frontalis), 8; pantropical spotted dolphin (S. attenuata), 6; and striped dolphin (S. coeruleoalba), 1. Eighteen groups could not be identified to species. C1 NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Pascagoula, MS 39568 USA. RP Roden, CL (reprint author), NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, PO Drawer 1207, Pascagoula, MS 39568 USA. NR 36 TC 8 Z9 10 U1 0 U2 7 PU UNIV PUERTO RICO, PI MAYAGUEZ PA COLLEGE ARTS SCIENCES, MAYAGUEZ, PUERTO RICO 00680 USA SN 0008-6452 J9 CARIBB J SCI JI Caribb. J. Sci. PY 2000 VL 36 IS 3-4 BP 280 EP 288 PG 9 WC Biodiversity Conservation SC Biodiversity & Conservation GA 407BV UT WOS:000167252300010 ER PT S AU Mandell, HC AF Mandell, HC BE McMillen, KR TI Breaking the Mars cost barrier: New management approaches are demanded SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO AB Human exploration missions of Mars and the Moon have been shown to be technically feasible, but a number of major barriers are in the way. The first of these is the perception, widely held, that human missions to Mars are prohibitively expensive. This perception results from several sources. First, NASA itself said in 1990 that such a mission could cost some $200 billion, based on cultural conditions, including management systems, which existed at that time. Other reasons include (often irrational) perceptions of the difficulty of such missions. The truth is that most of the technologies required to send humans to Mars are now in existence, and hence, development costs will be modest. The assumptions made by NASA in the 1990 costing exercise were based on a combination of national budgetary and cultural conditions which can not exist if humans are to again go beyond Earth orbit, and upon the mostly-false assumption that all systems will have to be developed from newly-created technology. Previous NASA studies have shown that costs are a function of the management style of the developing organization. New cost analysis methods have been created which utilize the cultural state of the management system as an independent variable, and are able to prescribe parameters of the management systems required to produce a given cost outcome. But a major challenge will be to turn a model-predicted management system into a cultural reality for whoever sends the first humans to Mars. Within NASA, we believe that we are the ones who can create the right management conditions. But the challenge has at least four dimensions. First, we must make sure that our estimates accurately reflect both the technical characteristics of our systems and the management culture to be employed. If, as suspected, the current management culture will not produce estimates low enough to be sold to the customer, new management structures must aggressively be developed which will produce lower cost programs. We must study our environment, in particular our customers and stakeholders, to assure in advance that we can communicate with them and that we have their support. We must understand how to better tailor our program plans and estimates to their levels of understanding. And we should assure that oversight groups have full ownership in our estimates before the estimates reach them in an official capacity. One way to achieve this is to co-opt key oversight individuals (Congressional staffers, OMB analysts) into the mission design and estimation processes. What is suggested is a new paradigm of management, designed to conform to a known outcome. It is a "Management Design to Cost" process unlike any other ever undertaken by NASA. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Mandell, HC (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 39 EP 50 PG 12 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500003 ER PT S AU Scott, DM AF Scott, DM BE McMillen, KR TI From Geo.S to Mars: Teaching the Mars kids SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO AB The first Martians are students in school right now. A good education will be the foundation for their successful missions to Mars. This is even more true if we seek to develop the most efficient and cost-effective human missions. This paper will describe NASA resources currently available to help teachers prepare the Mars Kids. Resources include the AESP program, the Teacher Resource Center Network, the educational products of the Center For Mars Exploration, and related teacher and student programs. The paper also describes a model for interdisciplinary learning called the Geo.S Paradigm. This model is derived from the work of author George R. Stewart. If students are to be successful in Mars Exploration and the world of the Third Millennium, they will need to use such a new way of thinking. Solid education of today's Mars kids will make a solid foundation for successful Mars exploration. C1 Oklahoma State Univ, NASA, Ames Res Ctr, Stillwater, OK 74078 USA. RP Scott, DM (reprint author), Oklahoma State Univ, NASA, Ames Res Ctr, Stillwater, OK 74078 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 99 EP 106 PG 8 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500009 ER PT S AU Shirley, D Bourke, R AF Shirley, D Bourke, R BE McMillen, KR TI Mars Exploration Program: An update SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Meeting Abstract CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shirley, D (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 UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 115 EP 115 PG 1 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500011 ER PT S AU Mitchell, TR AF Mitchell, TR BE McMillen, KR TI Affordable space transportation strategies for human exploration of Mars SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO AB The Marshall Space Flight Center (MSFC) is NASA's Lead Center for Space Transportation Systems Development. MSFC recently developed a Space Transportation Plan that contains the strategic architecture to develop revolutionary, affordable space transportation systems that will dramatically lower the cost of access to space. This paper describes the plans, strategies and roadmaps to achieve the goal of affordable transportation for human exploration of Mars. Some of the strategies discussed include: revitalizing the United States lead in high-performance rocket propulsion and earth-to-orbit transportation; enabling low-cost, high-efficiency cargo orbit transfer; and advanced space transportation concepts that will enable low-cost human exploration of the moon, Mars and beyond. C1 NASA, George C Marshall Space Flight Ctr, Program Plans & Requirements Off, Huntsville, AL 35812 USA. RP Mitchell, TR (reprint author), NASA, George C Marshall Space Flight Ctr, Program Plans & Requirements Off, Huntsville, AL 35812 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 161 EP 166 PG 6 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500015 ER PT S AU Perez, R AF Perez, R BE McMillen, KR TI Reliability issues for spacecraft electronic design SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO AB Over the next twenty years and starting now, NASA is initiating a program for Mars exploration where a series of small, cheaper spacecraft will be sent for a variety of missions, most of which have very simple objectives. Rather than sending expensive and necessarily more complex spacecraft to perform a series of multi-mission tasks, the approach is to send highly autonomous and simple spacecraft with a narrow mission objective. A multiple of these will then accomplish the desired goals of the science community. An implicit factor in the realization of these objectives is cost. In the electronics reliability area considerable changes need to be implemented in order to maintain the high levels of quality at the same time we analyze the reliability of spacecraft electronics in a much faster cycle. This paper addressed first the most important approaches concerning spacecraft electronic reliability design and how such approaches have been performed in the past. The paper discusses the difficulties in implementing these reliability cycles in the new era of smaller and faster design of spacecraft. This paper then proposes a simpler but highly integrated approach that would integrate design and reliability cycles. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Perez, 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 UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 167 EP 175 PG 9 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500016 ER PT S AU Sims, M AF Sims, M BE McMillen, KR TI Does automation and robotics lower costs? SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sims, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 351 EP 354 PG 4 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500033 ER PT S AU Stoker, CR AF Stoker, CR BE McMillen, KR TI Being there: The Mars surface mission SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO AB The design of the surface mission for a Mars Exploration program is reviewed. The mission design requirements follow from the mission goals: (1) perform scientific exploration of Mars and (2) assess the habitability of Mars. Science objectives are met by the crew performing a series of excursions in pressurized revers that are capable of supporting a crew of three for up to a month duration. They also teleoperate a suite of robotic revers at distances too far from the base to be accessed in pressurized revers. Habitability objectives are met by growing food and using in situ resources to support the base. Four major subsystems make up the base infrastructure: (1) a power system, (2) a consumables cache capable of supporting a 600 day mission and kept full by adding resources extracted from Mars, (3) piloted pressurized revers, and (4) habitats and greenhouses. All the base systems and activities are categorized according to three levels of criticality depending on whether they are necessary for life (life critical), mission success (mission critical), or augment mission capabilities (mission discretionary). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Stoker, CR (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 375 EP 386 PG 12 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500035 ER PT S AU McKay, CP Meyer, TR AF McKay, CP Meyer, TR BE McMillen, KR TI Introduction to the workshop SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 517 EP 517 PG 1 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500051 ER PT S AU Stoker, CR AF Stoker, CR BE McMillen, KR TI Programmatics and philosophy: Groundrules SO CASE FOR MARS VI: MAKING MARS AN AFFORDABLE DESTINATION SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 6th Case for Mars Conference CY JUL 17-20, 1996 CL UNIV COLORADO, BOULDER, CO SP Univ Colorado HO UNIV COLORADO C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Stoker, CR (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-461-3 J9 SCI TECH PY 2000 VL 98 BP 519 EP 520 PG 2 WC Engineering, Aerospace SC Engineering GA BP90G UT WOS:000086547500052 ER PT S AU Kwok, R Holt, B AF Kwok, R Holt, B BE Harris, RA Ouwehand, L TI Sea ice thickness from kinematics SO CEOS SAR WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT CEOS SAR Workshop CY OCT 26-29, 1999 CL TOULOUSE, FRANCE SP European Space Agcy, CNES, Comm Earth Observat Satellites ID ARCTIC-OCEAN; MODEL; PRESSURE AB High resolution 3-day surveys of the Arctic Ocean are currently being obtained using the Canadian RADARSAT synthetic aperture radar with its wide-swath ScanSAR mode. For the first time, we can produce basin-scale estimates of sea ice age and thickness from Lagrangian observations of ice motion derived from sequential SAR images of the Arctic Ocean. The deformation of material elements (cells) on the SAR imagery is computed using strain rates from ice motion. From the record of deformation of each cell, we estimate the ice age and thickness. In the winter, open water and thin ice are created when there is a positive change in area while negative area changes are associated with ridging. The deformation of the ice cover is sampled by cells with an initial area of approximately 10 km by 10 km. More than 60,000 of cells are used to cover the entire Arctic Ocean. These geophysical products can be put to a variety of uses: analyzing new ice climatologies, testing ice models or new ideas about sea ice rheology, and for assimilating into sea ice models. Thus far, we have produced estimates of sea ice deformation, thickness and age from five months of SAR data of the Arctic Ocean (November 1996 through March 1997). These data products are available on a web site at the Jet Propulsion Laboratory (http:www-radar.jpl.nasa.gov/rgps). Here, we describe this data set, their use for studies of the sea ice cover and the potential of using ENVISAT to extend these observations into the future. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-235, Pasadena, CA 91109 USA. NR 16 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 92-9092-641-4 J9 ESA SP PUBL PY 2000 VL 450 BP 65 EP 70 PG 4 WC Engineering, Aerospace SC Engineering GA BQ24P UT WOS:000087715400011 ER PT S AU Farr, TG Hensley, S Rodriguez, E Martin, J Kobrick, M AF Farr, TG Hensley, S Rodriguez, E Martin, J Kobrick, M BE Harris, RA Ouwehand, L TI The Shuttle Radar Topography Mission SO CEOS SAR WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT CEOS SAR Workshop CY OCT 26-29, 1999 CL TOULOUSE, FRANCE SP European Space Agcy, CNES, Comm Earth Observat Satellites AB The Shuttle Radar Topography Mission (SRTM), is a cooperative project between NASA and the National imagery and Mapping Agency. The mission is designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and south latitude. The DEM will have 30 m pixel spacing and about 15 m vertical errors. A rectified C-band radar image mosaic is also planned to be produced. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Farr, TG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 8 Z9 10 U1 0 U2 2 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-641-4 J9 ESA SP PUBL PY 2000 VL 450 BP 361 EP 363 PG 3 WC Engineering, Aerospace SC Engineering GA BQ24P UT WOS:000087715400054 ER PT J AU Bhatt, RT AF Bhatt, RT TI Tensile properties and microstructural characterization of Hi-nicalon SiC/RBSN composites SO CERAMICS INTERNATIONAL LA English DT Article DE tape casting; hot pressing; composites; mechanical properties; SiC; Si3N4; structural applications ID BONDED SILICON-NITRIDE AB The room temperature physical and mechanical properties of silicon carbide fiber-reinforced reaction-bonded silicon nitride matrix composites (SiC/RBSN) were measured, and the composite microstructure was analyzed. The composites consist of nearly 24 vol% of aligned Hi-Nicalon SiC fiber yarns in a similar to 30 vol% porous silicon nitride matrix. The fiber yarns were coated by chemical Vapor deposition with a 0.8 mu m layer of boron nitride (BN) followed by a 0.2. mu m layer of SIG. In the as-fabricated condition, both 1-D and 2-D composites exhibited high strength and graceful failure, and showed improved properties when compared with unreinforced matrix of comparable density. No indication of reaction between the SIC fiber and BN coating was noticed, bur the outer SiC layer reacted locally with the nitridation enhancing additive in the RBSN matrix. A comparison is made between the predicted and measured values of matrix cracking strength. Published by Elsevier Science Ltd and Techna S.r.l. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Bhatt, RT (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 17 TC 9 Z9 9 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0272-8842 J9 CERAM INT JI Ceram. Int. PY 2000 VL 26 IS 5 BP 535 EP 539 DI 10.1016/S0272-8842(99)00091-7 PG 5 WC Materials Science, Ceramics SC Materials Science GA 326LC UT WOS:000087736100013 ER PT B AU Eickelmann, N AF Eickelmann, N BE Khosrowpour, M TI Integrating the balanced scorecard and software measurement frameworks SO CHALLENGES OF INFORMATION TECHNOLOGY MANAGEMENT IN THE 21ST CENTURY LA English DT Proceedings Paper CT International Conference of the Information-Resources-Management-Association CY MAY 21-24, 2000 CL ANCHORAGE, AK SP Informat Resources Management Assoc AB This paper investigates the unique requirements to apply the Balanced Scorecard (BSC) in a government organization. Results from prior case studies are applied that identify key factors that differentiate the use of the BSC for non-profit government organizations versus industry or for profit organizations. The steps to build the Scorecard do not change significantly but do differ with respect to linking the four views. This is due to the required change in the BSC geography of making the customer objectives the top tier of the hierarchy and the financial objectives the second tie,: The BSC geography is mutated to accommodate the thematic focus of the customer This enables quantifying the financial value of IT investments relative to their contribution towards achieving the organization's strategic vision and goals as expressed in the customer thematic. C1 NASA, Facil 4&5, Software Res Lab, Fairmont, WV 26554 USA. RP Eickelmann, N (reprint author), NASA, Facil 4&5, Software Res Lab, 100 Univ Dr, Fairmont, WV 26554 USA. NR 18 TC 0 Z9 0 U1 0 U2 3 PU IDEA GROUP PUBLISHING PI HERSHEY PA 1331 E CHOCOLATE AVE, HERSHEY, PA 17033-1117 USA BN 1-878289-84-5 PY 2000 BP 980 EP 983 PG 2 WC Computer Science, Information Systems; Management SC Computer Science; Business & Economics GA BQ96N UT WOS:000165161400294 ER PT J AU Nigmatulin, TR Bonetto, FJ Larreteguy, AE Lahey, RT McQuillen, JB AF Nigmatulin, TR Bonetto, FJ Larreteguy, AE Lahey, RT McQuillen, JB TI An experimental study of dispersed liquid/liquid two-phase upflow in a pipe SO CHEMICAL ENGINEERING COMMUNICATIONS LA English DT Article DE dispersed two-phase flow; liquid/liquid flow; reduced gravity; LDA; PDA ID TURBULENCE AB This paper presents experimental data for dispersed liquid/liquid upflows. Water was the continuous phase and mineral oil was the dispersed droplet phase. For this how regime reduced gravity bubbly flow phenomena was simulated because the mineral oil and water had almost the same density. The mean velocity and turbulence fields, the size distributions of the oil droplets, the volume fraction, and interfacial area density distribution were measured using fiber optic Laser Doppler Anemometer (LDA) and phase Doppler Anemometer (PDA) systems. Significantly, the results presented in this paper are similar to those for bubbly air/water flows in microgravity conditions (Kamp et al., 1995). C1 Rensselaer Polytech Inst, Ctr Multiphase Flow, Troy, NY 12180 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Lahey, RT (reprint author), Rensselaer Polytech Inst, Ctr Multiphase Flow, Troy, NY 12180 USA. NR 18 TC 4 Z9 4 U1 2 U2 4 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 2000 VL 182 BP 121 EP 162 DI 10.1080/00986440008912831 PG 42 WC Engineering, Chemical SC Engineering GA 367AD UT WOS:000090038300008 ER PT S AU Bhartia, PK AF Bhartia, PK BE Zerefos, CS Isaksen, ISA Ziomas, I TI NASA's experience in deriving total ozone from satellites SO CHEMISTRY AND RADIATION CHANGES IN THE OZONE LAYER SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES C, MATHEMATICAL AND PHYSICAL SCIENCES LA English DT Proceedings Paper CT Conference of the NATO-Advanced-Study-Institute on Chemistry and Radiation Changes in Ozone Layer CY MAY 15-24, 1999 CL IRAKLION, GREECE SP NATO Sci Comm ID BACKSCATTER ULTRAVIOLET MEASUREMENTS; ROTATIONAL RAMAN-SCATTERING; ALGORITHM; RETRIEVAL; RADIATION; PROFILES; GOME C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Bhartia, PK (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 661, Greenbelt, MD 20771 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0258-2023 BN 0-7923-6514-3 J9 NATO ADV SCI I C-MAT PY 2000 VL 557 BP 293 EP 299 PG 7 WC Geochemistry & Geophysics; Environmental Sciences; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA BR63C UT WOS:000166983700026 ER PT J AU Syu, HH Neelin, JD AF Syu, HH Neelin, JD TI ENSO in a hybrid coupled model. Part I: sensitivity to physical parametrizations SO CLIMATE DYNAMICS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; NINO-SOUTHERN-OSCILLATION; SEA-SURFACE TEMPERATURE; GENERAL-CIRCULATION MODEL; FAST-WAVE LIMIT; EL-NINO; TROPICAL OCEAN; SEASONAL CYCLE; UNIFIED VIEW; INTERANNUAL VARIABILITY AB A hybrid coupled model (HCM) for the tropical Pacific ocean-atmosphere system is used to test the effects of physical parametrizations on ENSO simulation. The HCM consists of the Geophysical Fluid Dynamics Laboratory ocean general circulation model coupled to an empirical atmospheric model based on the covariance matrix of observed SST and wind stress anomaly fields. In this two-part work, part I describes the effects of ocean vertical mixing schemes and atmospheric spin-uptime on ENSO period. Part II addresses ENSO prediction using the HCM and examines the impact of initialization schemes. The standard version of the HCM exhibits spatial and temporal evolution that compare well to observations, with irregular cycles that tend to exhibit 3- and 4-year frequency-locking behavior. Effects in the vertical mixing parametrization that produce stronger mixing in the surface layer give a longer inherent ENSO period, suggesting model treatment of vertical mixing is crucial to the ENSO problem. Although the atmospheric spin-up time scale is short compared to ENSO time scales, it also has a significant effect in lengthening the ENSO period. This suggests that atmospheric time scales may not be truly negligible in quantitative ENSO theory. Overall, the form and evolution mechanism of the ENSO cycle is robust, even though the period is affected by these physical parametrizations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Neelin, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Neelin, J. David/H-4337-2011 NR 48 TC 23 Z9 27 U1 1 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD JAN PY 2000 VL 16 IS 1 BP 19 EP 34 DI 10.1007/PL00007920 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 273RW UT WOS:000084722000002 ER PT J AU Syu, HH Neelin, JD AF Syu, HH Neelin, JD TI ENSO in a hybrid coupled model. Part II: prediction with piggyback data assimilation SO CLIMATE DYNAMICS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; NINO SOUTHERN-OSCILLATION; SEA-SURFACE TEMPERATURE; EL-NINO; SEASONAL CYCLE; PREDICTABILITY; CHAOS; IRREGULARITY; PACIFIC; CLIMATE AB A hybrid coupled model (HCM) for the tropical Pacific ocean-atmosphere system is employed for ENSO prediction. The HCM consists of the Geophysical Fluid Dynamics Laboratory ocean general circulation model and an empirical atmospheric model. In hindcast experiments, a correlation skill competitive to other prediction models is obtained, so we use this system to examine the effects of several initialization schemes on ENSO prediction. Initialization with wind stress-data and initialization with wind stress reconstructed from SST using the atmospheric model give comparable skill levels. In re-estimating the atmospheric model iu order to prevent hindcast-period wind information from entering through empirical atmospheric model, we note some sensitivity to the estimation data set, but this is considered to have limited impact for ENSO-prediction purposes. Examination of subsurface heat content anomalies in these cases and a case forced only by the difference between observed and reconstructed winds suggests that at the current level of prediction skill. the crucial wind components for initialization are those associated with the slow ENSO mode, rather than with atmospheric internal variability. A "piggyback" suboptimal data assimilation is tested in which the Climate Prediction Center data assimilation product from a related ocean model is used to correct the ocean initial thermal field. This yields improved skill, suggesting thar not all ENSO prediction systems need to invest in costly data assimilation efforts, provided the prediction and assimilation models are sufficiently close. C1 Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. EM neelin@atmos.ucla.edu RI Neelin, J. David/H-4337-2011 NR 37 TC 27 Z9 31 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0930-7575 EI 1432-0894 J9 CLIM DYNAM JI Clim. Dyn. PD JAN PY 2000 VL 16 IS 1 BP 35 EP 48 DI 10.1007/s003820050003 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 273RW UT WOS:000084722000003 ER PT B AU Katz, DS Springer, PL AF Katz, DS Springer, PL GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Development of a spaceborne embedded cluster SO CLUSTER 2000: IEEE INTERNATIONAL CONFERENCE ON CLUSTER COMPUTING, PROCEEDINGS LA English DT Proceedings Paper CT 2nd Annual IEEE International Conference on Cluster Computing CY NOV 28-DEC 01, 2000 CL CHEMNITZ, GERMANY SP IEEE, IEEE, Comp Soc, IEEE,Task Force Cluster Comp, Alpha Process Inc, Compaq, Intel, Fujitsu Siemens, MPI Sofeware Tech Inc, Agilent Technol, Dolphin Interconnect Solut Inc, Synaps Ingenieur Gesell mbH, Sun Microsyst Gridware, TBZ-PARIV GmbH, SuSE Linux AG, Adakom GmbH AB Over the last decade and continuing into the foreseeable future, a trend has developed in the spacecraft industry of both number of missions and the amount of data taken by each mission increasing faster than bandwidth capabilities to send these data to Earth. The result of this trend is a bottleneck between data gathering (on-board) and data analysis ton the ground.) This bottleneck can be overcome by performing data analysis on-board and only transferring the results of this analysis to the ground, rather than the raw data. One attempt to do this is being made by the NASA HPCC Remote Exploration and Experimentation (REE) Project, which is developing spaceborne embedded clusters. Spaceborne embedded clusters share many characteristics of traditional, ground-based clusters such as POSIX-compliant operating systems and message-passing applications, but also have significant differences, including packaging and the need for fault tolerance and real-time scheduling in software. This paper discusses these similarities and differences, and how they impact application development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Katz, DS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM Daniel.S.Katz@jpl.nasa.gov; Paul.L.Springer@jpl.nasa.gov NR 7 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 90720-1264 USA BN 0-7695-0896-0 PY 2000 BP 119 EP 123 DI 10.1109/CLUSTR.2000.889012 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BR28D UT WOS:000166002300020 ER PT B AU Sterling, T AF Sterling, T GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI PC clusters - The convergence of high performance systems architecture SO CLUSTER 2000: IEEE INTERNATIONAL CONFERENCE ON CLUSTER COMPUTING, PROCEEDINGS LA English DT Proceedings Paper CT 2nd Annual IEEE International Conference on Cluster Computing CY NOV 28-DEC 01, 2000 CL CHEMNITZ, GERMANY SP IEEE, IEEE, Comp Soc, IEEE,Task Force Cluster Comp, Alpha Process Inc, Compaq, Intel, Fujitsu Siemens, MPI Sofeware Tech Inc, Agilent Technol, Dolphin Interconnect Solut Inc, Synaps Ingenieur Gesell mbH, Sun Microsyst Gridware, TBZ-PARIV GmbH, SuSE Linux AG, Adakom GmbH C1 NASA, JPL, Washington, DC 20546 USA. RP Sterling, T (reprint author), NASA, JPL, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0896-0 PY 2000 BP 267 EP 268 PG 2 WC Computer Science, Theory & Methods SC Computer Science GA BR28D UT WOS:000166002300044 ER PT S AU Kessel, RL AF Kessel, RL BE Harris, RA TI ISTP multi-point observations of Earths bow shock SO CLUSTER-II WORKSHOP MULTISCALE/MULTIPOINT PLASMA MEASUREMENTS, PROCEEDINGS SE ESA Special Publications LA English DT Proceedings Paper CT Cluster-II Workshop on Multiscale/Multipoint Plasma Measurements CY SEP 22-24, 1999 CL IMPERIAL COLL, LONDON, ENGLAND SP European Space Agcy, Imperial Coll HO IMPERIAL COLL AB We present interplanetary magnetic field (IMF) observations from Geotail and Wind in which the IMF was not uniform over spatial scales relevant to the magnetosphere. Geotail, at the dawn flank of the Earth's Low shock, measured magnetic field directions 60 degrees to 120 degrees different from the magnetic field measured by Wind on the duskside similar to 30 R-E upstream, during a 2-hour interval. One possible explanation of the difference between these observations is a kink in the magnetic field. It is probable that a persisting kink could drive surface waves on the bow shock. During this interval the bow shock does not fit a st and ard dawnside-quasi-parallel-duskside-quasi-perpendicular picture. Instead, both sides of the bow shock may have been locally quasiperpendicular. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. NR 9 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 92-9092-796-8 J9 ESA SPEC PUBL PY 2000 VL 449 BP 393 EP 396 PG 4 WC Engineering, Aerospace; Physics, Fluids & Plasmas SC Engineering; Physics GA BP86Q UT WOS:000086446900067 ER PT B AU Ivancic, WD Griner, JH Dimond, R Frantz, BD Kachmar, B Shell, D AF Ivancic, WD Griner, JH Dimond, R Frantz, BD Kachmar, B Shell, D GP AIAA AIAA TI Satellite communications using commercial protocols SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space-based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ivancic, WD (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 445 EP 452 PG 8 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200053 ER PT B AU Krawczyk, RJ Ignaczak, LR Gargione, F AF Krawczyk, RJ Ignaczak, LR Gargione, F GP AIAA AIAA TI Operational performance of the Advanced Communications Technology Satellite SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB The Advanced Communications Technology Satellite (ACTS) was launched by NASA in September 1993 as a geostationary test bed introducing new Ka-band technologies and capabilities to enable innovative new applications and services. The program, originally planned for two years with a design life of four years, has been operated in an inclined orbit since July of 1998, when stationkeeping fuel was exhausted, thus allowing the ACTS experiments to be extended into the seventh year. The decision to extend the life of the program was made by NASA because of the excellent performance of the communications payload and the versatility of the bus subsystems which continue to provide accurate pointing of the 0.3 degrees spot beams during inclined orbit operation. This paper discusses the various satellite subsystems, their as-designed and observed performance, the changes implemented to maintain pointing control in inclined orbit, and the significant operational experience to date. The paper also provides a description of the ground station capabilities used to support this unique spacecraft and the changes made to prepare them for inclined orbit operation. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Krawczyk, RJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 453 EP 461 PG 9 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200054 ER PT B AU Acosta, R Johnson, S AF Acosta, R Johnson, S GP AIAA AIAA TI Ka band system and propagation effects on system performance SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB The Advanced Communication Technology Satellite (ACTS) is an experimental communications satellite system launched in September 1993. ACTS introduces many new technologies, including operation in the Ka frequency band. ACTS uses multiple hopping narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for a bit-error-rates of 5x10(-7) or better over the continental United States. In order to maintain a minimum system availability of 99.5% over ail US rain zones ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterization considering the statistical effects of system variances due to thermal and propagation effects over 6 years of ACTS operation including inclined orbit. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Acosta, R (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 462 EP 469 PG 8 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200055 ER PT B AU Zernic, MJ Bauer, RA AF Zernic, MJ Bauer, RA GP AIAA AIAA TI The role of the ACTS Experiments Program in preparation of future systems SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB Next generation satellite systems will provide wider bandwidth capability than current systems and will be an integral part of national and global communication networks. Networks of today are increasingly becoming Internet based. As the Internet continues its unprecedented growth, there will be an integration of wired, wireless, and satellite distribution paths. The Advanced Communications Technology Satellite (ACTS) continues to serve as a national testbed for the development of advanced networking technologies and applications needed for these integrated networks. This paper provides synopses of the design, implementation, and highlights of results of significant ACTS networking experiment activities in the context of their relevance to NASA's mission and impact upon the communications industry. These experiments cover areas in the development of standards and protocols, refinement of commercial products and services, and the expansion of the information infrastructure. Various experimenters continue to use the ACTS system to test, evaluate, and demonstrate activities in the area of networking, protocol evaluation and interoperability, and supporting other government efforts in transitioning to the use of next generation commercial systems. Those activities that occurred during the first year of inclined orbit operations are highlighted. In conclusion, NASA's plans to build upon these experiences will be summarized. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zernic, MJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 470 EP 480 PG 11 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200056 ER PT B AU Comberiate, A LeRoy, B AF Comberiate, A LeRoy, B GP AIAA AIAA TI Application of advanced TDRS technologies to a MARS Data Relay infrastructure SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB In this paper we examine a number of the newer technologies being fielded for the TDRS H,I,J for application to the Mars Data Relay Mission. Specifically, we examine: the utility of the basic satellite physical architecture employing articulated high gain antennas; the use of tunable channelized Ka-band repeating transponders; the utility of on-board beamforming active phased arrays; the operational autonomy; and other technologies. Based on a reasonable traffic scenario for near-term Mars exploration, we develop communications and spacecraft operational concepts and demonstrate the feasibility of TDRS technology application. We conclude that a smaller version of TDRS could be deployed to Mars as part of a constellation providing continuous daylight coverage to Mars exploration missions. The smaller TDRS does not depend on advanced technology development and could be deployed in the near term. Deployment would reduce the explorer's communications burden by using the cruise phase X-band communications for both high-rate and low-rate in-situ communications. C1 NASA, Goddard Space Flight Ctr, TDRS Project Off, Greenbelt, MD 20771 USA. RP Comberiate, A (reprint author), NASA, Goddard Space Flight Ctr, TDRS Project Off, Code 454, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 1 U2 3 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 644 EP 654 PG 11 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200078 ER PT B AU Kerczewski, RJ Chomos, GJ Griner, JH Mainger, SW Martzaklis, KS Kachmar, BA AF Kerczewski, RJ Chomos, GJ Griner, JH Mainger, SW Martzaklis, KS Kachmar, BA GP AIAA AIAA TI A hybrid satellite-terrestrial approach to aeronautical communication networks SO COLLECTION OF THE 18TH AIAA INTERNATIONAL COMMUNICATIONS SATELLITE SYSTEMS CONFERENCE AND EXHIBIT, TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 18th AIAA International Communications Satellite Systems Conference and Exhibit CY APR 10-14, 2000 CL OAKLAND, CA SP Amer Inst Aeronaut & Astronaut, IEEE AB Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kerczewski, RJ (reprint author), NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-373-9 PY 2000 BP 892 EP 900 PG 9 WC Engineering, Aerospace SC Engineering GA BP95D UT WOS:000086712200107 ER PT B AU Hilburger, MW Starnes, JH AF Hilburger, MW Starnes, JH GP AIAA AIAA TI Effects of imperfections on the buckling response of compression-loaded composite shells SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The results of an experimental and numerical study of the effects of imperfections on the buckling response of unstiffened thin-walled composite cylindrical shells are presented. Results that identify the individual and combined effects of traditional initial geometric shell-wall imperfections and non-traditional shell-wall thickness variations, shell-end geometric imperfections and variations in loads applied to the ends of the shells on the shell buckling response are included. In addition, results illustrating the effects of manufacturing flaws in the form of gaps between adjacent pieces of graphite-epoxy tape in some of the laminate plies are presented in detail. The shells have been analyzed with a nonlinear finite-element analysis code that accurately accounts for these effects on the buckling and nonlinear responses of the shells. The numerical results indicate that traditional and nontraditional initial imperfections can cause a significant reduction in the buckling load of a compression-loaded composite shell. Furthermore, the results indicate that the imperfections couple in a nonlinear manner. The numerical results correlate well with the experimental results. The nonlinear analysis results are also compared to the results from a traditional linear bifurcation buckling analysis. The results suggest that the nonlinear analysis procedure can be used for determining accurate, high-fidelity design knockdown factors for shell buckling and collapse. The results can also be used to determine the effects of manufacturing tolerances on the buckling response of composite shells. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hilburger, MW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 423 EP 437 PG 5 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900042 ER PT B AU Lake, MS Hachkowski, MR AF Lake, MS Hachkowski, MR GP AIAA AIAA TI Mechanism design principles for optical-precision, deployable instruments SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The present paper is intended to be a guide for the design of "microdynamically quiet" deployment mechanisms for optical-precision structures, such as deployable telescope mirrors and optical benches. Many of the guidelines included herein come directly from the field of optomechanical engineering, and are neither newly developed guidelines nor are they uniquely applicable to high-precision deployment mechanisms. However, the application of these guidelines to the design of deployment mechanisms is a rather new practice, so efforts are made herein to illustrate the process through the discussion of specific examples. The present paper summarizes a more extensive set of design guidelines for optical-precision mechanisms that are under development. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lake, MS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 592 EP 600 PG 3 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900060 ER PT B AU Young, RD Rose, CA Starnes, JH AF Young, RD Rose, CA Starnes, JH GP AIAA AIAA TI Nonlinear bulging factors for longitudinal and circumferential cracks in cylindrical shells subjected to combined loads SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Results of a geometrically nonlinear finite element parametric study to determine curvature correction factors or "bulging factors" that account for increased crack-tip stresses due to curvature for longitudinal and circumferential cracks in unstiffened cylindrical shells subjected to combined loads are presented. Nondimensional parameters varied in the study include the shell curvature parameter, lambda, which is a function of the shell radius, the shell wall thickness, and the crack length; a pressure loading parameter, eta, which is a function of the shell geometry, material properties and the applied internal pressure; and a biaxial loading parameter, chi, which is the ratio of the farfield axial stress to the farfield circumferential stress. The major results are presented in the form of contour plots of the bulging factor as a function of these three nondimensional parameters. These plots identify the ranges of the shell curvature and loading parameters for which the effects of geometric nonlinearity are significant, and show the effect of the biaxial loads on the value of the bulging factor. Simple empirical expressions for the bulging factor are then derived from the numerical results and are shown to predict accurately the nonlinear response of shells with longitudinal and circumferential cracks. C1 NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Young, RD (reprint author), NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. NR 28 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1064 EP 1078 PG 3 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900110 ER PT B AU Sobieszczanski-Sobieski, J Kodiyalam, S Yang, RJ AF Sobieszczanski-Sobieski, J Kodiyalam, S Yang, RJ GP AIAA AIAA TI Optimization of car body under constraints of noise, vibration, and harshness (NVH), and crash SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB A car body structure was optimized for minimum weight under the constraints of noise, vibration, and harshness (NVH), and a crash event, using up to 254 concurrently operating processors. The crash analysis alone, if executed on a single processor and repeated the number of times this optimization required, would have taken 257 days of elapsed computing time. Parallel processing has compressed the elapsed time to one day demonstrating how a multiprocessor machine may be useful in solving engineering tasks that heretofore were regarded as intractable, The optimization procedure transformed the structure initially infeasible to one having its weight reduced and all the constraints satisfied. The experience gained in the reported application indicated it is important to tailor the solution method to the characteristics of the multiprocessor computer architecture and to understand the data handling options offered by that architecture. Another conclusion drawn from this case is that the coarse-grained parallelism whereby an existing code is being replicated over an array of processors should be regarded as an effective way of utilization of multiprocessor machines, immediately available in the interim before solutions are redeveloped from ground up specifically for that class of machines. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Sobieszczanski-Sobieski, J (reprint author), NASA, Langley Res Ctr, MS 139, Hampton, VA 23665 USA. NR 9 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1113 EP 1128 PG 6 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900114 ER PT B AU Whorton, M Calise, AJ AF Whorton, M Calise, AJ GP AIAA AIAA TI Fixed-order mixed norm designs for building vibration control SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID FEEDBACK AB This study investigates the use of H-2, mu-synthesis, and mixed N-2/mu methods to construct full order controllers and optimized controllers of fixed dimensions. The benchmark problem definition is first extended to include uncertainty within the controller bandwidth in the form of parametric uncertainty representative of uncertainty in the natural frequencies of the design model. The sensitivity of H-2 design to unmodeled dynamics and parametric uncertainty is evaluated for a range of controller levels of authority. Next, mu-synthesis methods are applied to design full order compensators that are robust to both unmodeled dynamics and to parametric uncertainty. Finally, a set of mixed H-2/mu compensators are designed which are optimized for a fixed compensator dimension. These mixed norm designs recover the H-2, design performance levels while providing the same levels of robust stability as the mu designs. It is shown that designing with the mixed norm approach permits higher levels of controller authority for which the H-2 designs are destabilizing. The benchmark problem is that of an active tendon system. The controller designs are all based on the use of acceleration feedback. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Whorton, M (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 18 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1271 EP 1279 PG 5 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900129 ER PT B AU Baker, DJ Rousseau, CQ AF Baker, DJ Rousseau, CQ GP AIAA AIAA TI Analysis and test of repair concepts for a carbon-rod reinforced laminate SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The use of pultruded carbon-epoxy rods for the reinforcement of composite laminates in some structures results in an efficient structural concept. The results of an analytical and experimental investigation of repair concepts of completely severed carbon-epoxy rods is presented. Three repair concepts are considered: (a) bonded repair with outside moldline and inside moldline doublers; (b) bonded repair with fasteners, and (c) bonded repair with outside moldline doubler only. The stiffness of the repairs was matched with the stiffness of the baseline specimen. The failure strains for the bonded repair with fasteners and the bonded repair with an outside moldline doubler exceeded a target design strain set for the repair concepts. C1 NASA, Langley Res Ctr, ARL, Vehicle Technol Directorate,Mech & Durab Branch, Hampton, VA 23681 USA. RP Baker, DJ (reprint author), NASA, Langley Res Ctr, ARL, Vehicle Technol Directorate,Mech & Durab Branch, Hampton, VA 23681 USA. NR 10 TC 0 Z9 0 U1 0 U2 2 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1421 EP 1430 PG 4 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900145 ER PT B AU Hilburger, MW Nemeth, MP Starnes, JH AF Hilburger, MW Nemeth, MP Starnes, JH GP AIAA AIAA TI Effective widths of compression-loaded plates with a cutout SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB A study of the effects of cutouts and laminate construction on the prebuckling and initial postbuckling stiffnesses, and the effective widths of compression-loaded laminated-composite and aluminum square plates is presented. The effective-width concept is extended to plates with a cutout and, experimental and nonlinear finite-element analysis results are presented. Behavioral trends are compared for seven plate families and for cutout-diameter-to-plate-width ratios up to 0.66. A general, compact design curve, that can be used to present and compare the effective widths for a wide range of laminate constructions, is also presented. A discussion of how the results can be used and extended to include certain types of damage, cracks, and other structural discontinuities or details is given. Several behavioral trends are described that initially appear to be nonintuitive. The results demonstrate a complex interaction between cutout size and plate membrane and bending orthotropies that affects the axial stiffness and effective width of a plate subjected to compression loads. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hilburger, MW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1586 EP 1603 PG 4 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900160 ER PT B AU Nemeth, MP Smeltzer, SS AF Nemeth, MP Smeltzer, SS GP AIAA AIAA TI Bending boundary layers in laminated-composite circular cylindrical shells SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID INTERNAL-PRESSURE AB An analytical, parametric study of the attenuation of bending boundary layers or edge effects in balanced and unbalanced, symmetrically and unsymmetrically laminated thin cylindrical shells is presented for nine contemporary material systems. The analysis is based on the linear Sanders-Koiter shell equations and specializations to the Love-Kirchhoff shell equations and Donnell's equations are included. Two nondimensional parameters are indentified that characterize and quantify the effects of laminate orthotropy and laminate anisotropy on the bending boundary-layer decay length in a very general and encompassing manner. A substantial number of structural design technology results are presented for a wide range of laminated-composite cylinders. For all the laminate constructions considered, the results show that the differences between results that were obtained with the Sanders-Koiter shell equations, the Love-Kirchhoff shell equations, and Donnell's equations are negligible. The results also show that the effect of anisotropy in the form of coupling between pure bending and twisting has a neglible effect on the size of the bending boundary-layer decay length of the balanced, symmetrically laminated cylinders considered. Moreover, the results show that coupling between the various types of shell anisotropies has a negligible effect on the calculation of the bending boundary-layer decay length in most cases. The results also show that in some cases neglecting the shell anisotropy results in underestimating the bending boundary-layer decay length and in other cases it results in an overestimation. C1 NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Nemeth, MP (reprint author), NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1614 EP 1645 PG 4 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900162 ER PT B AU Gates, TS Whitley, KS AF Gates, TS Whitley, KS GP AIAA AIAA TI Long-term durability of polymer matrix composites under simulated supersonic flight profile testing SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID BEHAVIOR; CREEP AB Studies to establish such long-term durability of candidate materials for supersonic commercial aircraft were recently conducted. Results of residual mechanical properties from tests of a candidate PMC material subjected to a realistic thermal-mechanical environment for time periods up to 15,000 test hours are presented. Property changes, as measured by mechanical tests of coupons, are presented as a function of the number of aging hours and aging conditions. Analysis of these comparisons has provided the data to assess the relative importance of each experimental factor. The different degradation mechanisms are assessed and their impact on material performance are ranked according to exposure time and test conditions. C1 NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Gates, TS (reprint author), NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1829 EP 1840 PG 6 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900176 ER PT B AU Moses, RW Huttsell, L AF Moses, RW Huttsell, L GP AIAA AIAA TI Fin buffeting features of an early F-22 model SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID SCALE WIND-TUNNEL; PRESSURE MEASUREMENTS; F/A-18 TAIL AB Fin buffeting is an aeroelastic phenomenon encountered by high performance aircraft, especially those with twin vertical tails that must operate at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. To date, the buffet (unsteady pressures) and buffeting (structural response) characteristics of the F-15 and F/A-18 fins have been studied extensively using flow visualization, flow velocity measurements, pressure transducers, and response gages. By means of wind-tunnel and flight tests of the F-15 and F/A-18, this phenomenon Is well studied to the point that buffet loads can be estimated and fatigue life can be increased by structural enhancements to these airframes. However, prior to the present research, data was not available outside the F-22 program regarding fin buffeting on the F-22 configuration. During a test in the Langley Transonic Dynamics Tunnel, flow visualization and unsteady fin surface pressures were recorded for a 13.3%-scale F-22 model at high angles of attack for the purpose of comparing with results available for similar aircraft configurations. Details of this test and fin buffeting are presented herein. C1 NASA, Langley Res Ctr, Aeroelastic Branch, Hampton, VA 23665 USA. RP Moses, RW (reprint author), NASA, Langley Res Ctr, Aeroelastic Branch, Hampton, VA 23665 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1922 EP 1931 PG 2 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900184 ER PT B AU Silva, WA Keller, DF Florance, JR Cole, SR Scott, RC AF Silva, WA Keller, DF Florance, JR Cole, SR Scott, RC GP AIAA AIAA TI Experimental steady and unsteady aerodynamic and flutter results for HSCT semispan models SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB One objective of the Aeroelasticity element of the High Speed Research (HSR) program was to provide validated analyses, design tools, and demonstrated technology readiness to accurately predict and solve the aeroelastic problems of advanced high-speed civil aircraft, As part of this task, a wind-tunnel models subtask was created to measure and document the aeroelastic characteristics, the steady and unsteady pressures and forces, and the aeroelastic stability boundaries for models of increasing complexity. This paper presents results from three wind-tunnel tests using two HSR semispan models. C1 NASA, Langley Res Ctr, Aeroelastic Branch, Hampton, VA 23681 USA. RP Silva, WA (reprint author), NASA, Langley Res Ctr, Aeroelastic Branch, Hampton, VA 23681 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 1943 EP 1953 PG 5 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900186 ER PT B AU de la Fuente, H Raboin, JL Spexarth, GR Valle, GD AF de la Fuente, H Raboin, JL Spexarth, GR Valle, GD GP AIAA AIAA TI TransHab: NASA's large-scale inflatable spacecraft SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 1 PTS 1-3 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB TransHab is a, 27-foot diameter by 40-foot, lightweight inflatable habitation module for space applications. TransHab consists of a lightweight graphite-composite core, 11-foot diameter by 23-foot tall, surrounded by a 27-foot diameter inflatable shell. Originally envisioned to be the habitation module of an interplanetary transit vehicle, TransHab is currently being considered as a module for use on the International Space Station (ISS). During the past two years, several tests have been performed at the NASA/Johnson Space Center to demonstrate and prove the technologies required in building a large-scale inflatable habitation module. This paper discusses the results of these tests which including the following: 1) a structural integrity development test article hydrostatically tested to four times ambient pressure, 2) a full-scale development test article manufactured assembled, folded and deployed at vacuum, and 3) extensive hypervelocity impact testing of the micrometeoroid and orbital debris protection system. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP de la Fuente, H (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code EX14, Houston, TX 77058 USA. NR 11 TC 0 Z9 0 U1 1 U2 2 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA BN 1-56347-449-2 PY 2000 BP 2157 EP 2165 PG 3 WC Engineering, Aerospace SC Engineering GA BQ24X UT WOS:000087725900209 ER PT B AU Raney, DL Montgomery, RC Green, LL Park, MA AF Raney, DL Montgomery, RC Green, LL Park, MA GP AIAA AIAA TI Flight control using distributed shape-change effector arrays SO COLLECTION OF THE 41ST AIAA/ASME /ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 2 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Recent discoveries in material science and fluidics have been used to create a variety of novel effector devices that offer great potential to enable new approaches to aerospace vehicle flight control. Examples include small inflatable blisters, shape-memory alloy diaphragms, and piezoelectric patches that may be used to produce distortions or bumps on the surface of an airfoil to generate control moments. Small jets have also ken used to produce a virtual shape-change through fluidic means by creating a recirculation bubble on the surface of an airfoil. An advanced aerospace vehicle might use distributed arrays of hundreds of such devices to generate moments for stabilization and maneuver control, either augmenting or replacing conventional ailerons, flaps or rudders. This research demonstrates the design and use of shape-change device arrays for a tailless aircraft in a low-rate maneuvering application. A methodology for assessing the control authority of the device arrays is described, and a suite of arrays is used in a dynamic simulation to illustrate allocation and deployment methodologies. Although the authority of the preliminary shape-change array designs studied in this paper appeared quite low, the simulation results indicate that the effector suite possessed sufficient authority to stabilize and maneuver the vehicle in mild turbulence. C1 NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23681 USA. RP Raney, DL (reprint author), NASA, Langley Res Ctr, Dynam & Control Branch, MS 132, Hampton, VA 23681 USA. NR 20 TC 0 Z9 0 U1 1 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 156 EP 167 PG 12 WC Engineering, Aerospace SC Engineering GA BQ24Y UT WOS:000087726300017 ER PT B AU Engberg, RC Lassiter, JO McGee, JK AF Engberg, RC Lassiter, JO McGee, JK GP AIAA AIAA AIAA TI Modal survey test of the SOTV 2x3 meter off-axis inflatable concentrator SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 4 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Marshall Space Flight Center (MSFC) has had several projects involving inflatable space structures. A flight project called Shooting Star Experiment initiated the first detailed design, analysis, and testing effort involving an inflatable concentrator. The concentrator supported a Fresnel lens that concentrated the Sun's rays and provided heat transfer for an experimental solar propulsion engine. Research and development activities for solar propulsion engine technology and inflatable space structures have continued after the conclusion of this experiment. Experience gained in conducting modal survey tests of inflatable structures for the Shooting Star Experiment has been used by dynamic test engineers at MSFC to conduct a modal survey test on a Solar Orbital Transfer Vehicle (SOTV) off-axis inflatable concentrator. This paper describes how both previously learned and newly developed test methods addressing the unique test requirements for inflatable structures were used. Effects of the inherent nonlinear response of the inflatable concentrator on test methods and test results are noted as well. Nine analytical mode shapes were successfully correlated to test mode shapes. The paper concludes with several "lessons learned" applicable to future dynamics testing and shows how MSFC has utilized traditional and new methods for modal survey testing of inflatable space structures. C1 NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Huntsville, AL 35812 USA. RP Engberg, RC (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Huntsville, AL 35812 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 48 EP 59 PG 12 WC Engineering, Aerospace SC Engineering GA BQ25A UT WOS:000087727100007 ER PT B AU Adams, ML Culver, HL Kaufman, DM Pacini, LK Sturm, J Lienard, S AF Adams, ML Culver, HL Kaufman, DM Pacini, LK Sturm, J Lienard, S GP AIAA AIAA AIAA TI Design and flight testing of an inflatable sunshield for the NGST SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 4 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The Next Generation Space Telescope (NGST) mission is scheduled to launch in 2007 and be stationed at L2 for a mission life of ten years. The large aperture mirror and optical detectors aboard NGST require shielding from the constant solar energy seen at this orbit. The government reference NGST design, called the Yardstick, baselined a sunshield using an inflation deployment system. During the formulation phase, NGST is spending approximately 25% of the overall budget to foster the development of new technology. The goal is to develop and demonstrate enabling or enhancing technology and provide innovative solutions for the design of the NGST observatory. Inflatable technology falls in the category of enhancing technology due to its advantages in weight, stowed volume and cost. The Inflatable Sunshield in Space (ISIS) flight experiment will provide a realistic space flight demonstration of an inflatable sunshield. The supporting technology development program will provide an information base for the design, manufacture, assembly and testing of large thin membranes and inflatable structural elements for space structures. The ISIS experiment will demonstrate the feasibility of using inflatable technology to passively cool optical systems for NGST and provide correlation between analytical predictions and on orbit results. The experiment will be performed on a Hitchhiker/Space Shuttle mission in late 2001. The ISIS mission is an effort to address several major technical challenges of the NGST inflatable sunshield, namely controlled inflation deployment, planarity and separation of large stretched membranes, space rigidization of inflatable booms, and dynamic modeling and simulation. Success requirements for the mission are: the sunshield deploys and inflates as expected in a controlled manner; the sunshield withstands environmental loading after boom venting; measurements are obtained that characterize the shield deployment behavior; measurements are obtained that characterize the sunshield post deployment dynamics; and structural properties and measurements obtained during the mission validate the analytical model of the sunshield. As mission operations and design constraints permit, secondary mission measurements will be taken on membrane separation and flatness, structural interactions with the deployable mast and thermal performance of the sunshield. The ISIS experiment is a sunshield that is one-third the size of the NGST sunshield. NASA-GSFC is partnering with ILC Dover, Inc. of Frederica, Delaware to provide the sunshield flight hardware for the experiment. The ISIS sunshield refers to all film layers, film management devices, booms, boom end tip assemblies, boom controlled deployment devices and rigidization systems. There are four booms on the sunshield of various lengths; the longest boom is approximately 17 feet long, another boom is approximately 14 feet long and the two remaining booms are approximately 6 feet long each. Each of the booms is comprised of an inflatable boom, a ladder assembly and a system to heat cure the boom. The inflatable boom is a thermoset composite material with an inside diameter of 5.125 ". The inflatable booms are pliable prior to curing the resin. This allows them to be flattened, relied and stowed on a boom tip assembly cylinder attached to a ladder structure at the tip of the boom prior to inflation. The ladder structure provides separation of the membrane layers, 2.5-cm separation at the container interface and a 15.0-cm separation at the edge. When ISIS on-orbit operations commence, the booms are inflated with nitrogen gas at a low pressure (approximately 3.2psi). The booms unroll in a "party favor" fashion from the cylinder at the boom tip. A wire brake mechanism is used to control the rate of deployment. The controlled deployment device is located inside the cylinder at the tip of the boom. Once the booms have completely deployed, they are heated for approximately 45 minutes at 120 degrees C to cure the resin. The booms are then vented. The sunshield is comprised of four membrane layers, made of reinforced Kapton VN, 0.0005 " thick. The six inner membrane surfaces will be coated with 1000 Angstroms of Vacuum Deposited Aluminum (VDA), the outer two surfaces are bare kapton. A rip stop system is incorporated into the high stress areas of each layer to inhibit tear propagation of the membrane. As the NGST observatory moves to map different parts of the sky, rotational and translational loads will be seen by the sunshield booms. The focus of testing the post-deployed ISIS sunshield will be the simulation of the predicted loads that the NGST observatory will encounter. Once the ISIS sunshield booms have been rigidized, the sunshield will be excited via Shuttle maneuvering that simulates NGST observatory movements. Data will be gathered from accelerometers and load cells to characterize the behavioral respose of the sunshield due to the excitation source. This data will enable the NGST dynamic models to be validated. This paper will describe the design of the flight experiment and the testing to be performed on-orbit. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Adams, ML (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 1 TC 13 Z9 14 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 111 EP 119 PG 9 WC Engineering, Aerospace SC Engineering GA BQ25A UT WOS:000087727100014 ER PT B AU Wasfy, TM Noor, AK AF Wasfy, TM Noor, AK GP AIAA AIAA TI Multibody dynamic simulation of the next generation space telescope using finite elements and fuzzy sets SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 5 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID SYSTEMS AB Multibody dynamic simulations are performed for a large deployable space structure using finite element models and an explicit temporal integration procedure. The structure considered is NASA's light-weight, 8 m-aperture next generation space telescope (NGST). The NGST structure consists of beam components (modeled using beam "super-elements," each composed of two truss elements and a torsional spring), thin-surface shell-type components (modeled using super-elements, each composed of one brick, twelve truss elements, and six surface elements), revolute and prismatic joints, and reaction wheels. Detailed numerical simulations are conducted for the vibrational response, attitude control, and deployment. A fuzzy-set technique is used to assess the effect of changing the dwell time of the various deployment actuators on the total strain energy of the structure. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA USA. RP Wasfy, TM (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 24 EP 37 PG 14 WC Engineering, Aerospace SC Engineering GA BQ25B UT WOS:000087727500003 ER PT B AU Peck, J Brunty, J AF Peck, J Brunty, J GP AIAA AIAA TI X33 transient liftoff analysis SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 5 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The successful design of a launch vehicle requires the careful characterization of the various loads the structure will experience over its lifetime. Many of the most demanding load environments occur during the launch/ascent phase of a mission, typically defined as the point of engine start through engine cut off. One of the critical events during the launch phase is the liftoff event. This event imparts high loads on the vehicle due to transient events such as thrust build-up and vehicle release. This paper describes the theory and procedures used to calculate structural loads due to the liftoff event for the Lockheed-Martin X33 technology demonstrator vehicle. These procedures were developed at NASA's Marshall Space Flight Center and verified previously on other advanced launch system concepts and the Space Shuttle system. C1 NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. RP Peck, J (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 47 EP 58 PG 12 WC Engineering, Aerospace SC Engineering GA BQ25B UT WOS:000087727500005 ER PT B AU Hidalgo, H AF Hidalgo, H GP AIAA AIAA TI An innovative structural mode selection methodology: Application for the X-33 launch vehicle finite element model SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 5 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB An innovative methodology for determining structural target mode selection and mode selection based on a specific criterion is presented. An effective approach to single out modes which interact with specific locations on a structure has been developed for the X-33 Launch Vehicle Finite Element Model (FEM). The presented Root-Sum-Square (RSS) displacement method computes resultant modal displacement for each mode at selected degrees of freedom (DOF) and sorts to locate modes with highest values. This method was used to determine modes, which most influenced specific locations/points on the X-33 flight vehicle such as avionics control components, aero-surface control actuators, propellant valve and engine points for use in flight control stability analysis and for flight POGO stability analysis. Additionally, the modal RSS method allows for primary or global target vehicle modes to also be identified in an accurate and efficient manner. C1 NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. RP Hidalgo, H (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Mech & Thermal Dept, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 83 EP 92 PG 10 WC Engineering, Aerospace SC Engineering GA BQ25B UT WOS:000087727500007 ER PT B AU Fowler, SB AF Fowler, SB GP AIAA AIAA TI Flutter analysis of the X33 SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 5 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Flutter analysis performed in support of the X33 Advanced Technology Demonstrator is described. Analysis was conducted over a range of flow regimes using several different analysis codes. The finite element and aerodynamic models used in the analysis have undergone several years of development and refinement resulting in a high degree of model detail. The flutter analysis focuses on the area of three critical points within the vehicle's design trajectory at which full sets of external loads have previously been developed. A comparison between several different aerodynamic models is also made for the selected trajectory points. C1 NASA, George C Marshall Space Flight Ctr, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. RP Fowler, SB (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 93 EP 102 PG 10 WC Engineering, Aerospace SC Engineering GA BQ25B UT WOS:000087727500008 ER PT B AU McGhee, DS AF McGhee, DS GP AIAA AIAA TI A strategy for integrating a large finite element model: X-33 lessons learned SO COLLECTION OF THE 41ST AIAA/ASME/ASCE/AHS/ASC STRUCTURES, STRUCTURAL DYNAMICS, AND MATERIALS CONFERENCE AND EXHIBIT, VOL 5 LA English DT Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 41st Structures, Structural Dynamics, and Materials Conference CY APR 03-06, 2000 CL ATLANTA, GA SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The X-33 vehicle is an advanced technology demonstrator sponsored by NASA. For the past three years the Structural Dynamics & Loads Group of NASA's Marshall Space Flight Center has had the task of integrating the X-33 vehicle structural finite element model. In that time, five versions of the integrated vehicle model have been produced and a strategy has evolved that would benefit anyone given the task of integrating structural finite element models that have been generated by various modelers and companies. The strategy that has been presented here consists of six decisions that need to be made. These six decisions are: purpose of model, units, common material list, model numbering, interface control, and archive format. This strategy has been proved and expanded from experience on the X-33 vehicle. C1 NASA, George C Marshall Space Flight Ctr, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. RP McGhee, DS (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Dynam & Loads Grp ED21, Huntsville, AL 35812 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUTICS & ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DR, STE 500, RESTON, VA 20191-4344 USA PY 2000 BP 103 EP + PG 7 WC Engineering, Aerospace SC Engineering GA BQ25B UT WOS:000087727500009 ER PT J AU King, MD Nayagam, V Williams, FA AF King, MD Nayagam, V Williams, FA TI Measurements of polymethyl methacrylate diffusion flames in von Karman swirling flows SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article ID STRAINED PREMIXED FLAMES; ROTATION; EXTINCTION; RATES AB In 1921 an analysis by von Karman demonstrated that viscous pumping action occurs when a flat disk is rotated in a fluid of semi-infinite extent. The rotation draws material inward normal to the disk, forcing it radially outward, thereby causing a swirling motion. A similarity exists near the disk. in the vicinity of the centerline, such that the radial and tangential velocity components are proportional to the radius, while all other flow properties depend only on the distance normal to the disk. If the disk is a fuel and the ambient fluid is an oxidizing gas, then a flat laminar diffusion flame parallel to the disk can be established in the swirling flow drawn in. Theoretical descriptions of such flames have been developed previously, and some experiments have been performed, notably for disks of polymethyl methacrylate (PMMA) in air. The present contribution provides quantitative measurements of burning rates and flame stand-off distances for such rotating disks and demonstrates that time-dependent heating of the fuel is important under these conditions, while nearly steady-state conditions apply in the gas. The fully steady-state solutions that have been published would apply to PMMA only for combustion in oxygen-enriched atmospheres for the sample sizes and rotational rates of the present experiments. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. San Diego State Univ, Dept Mech Engn, San Diego, CA 92182 USA. RP Nayagam, V (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, MS110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 3 Z9 3 U1 0 U2 4 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2000 VL 160 BP 151 EP 163 DI 10.1080/00102200008935800 PG 13 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 418AJ UT WOS:000167867400008 ER PT J AU Dietrich, DL Ross, HD Shu, Y Chang, P T'ien, JS AF Dietrich, DL Ross, HD Shu, Y Chang, P T'ien, JS TI Candle flames in non-buoyant atmospheres SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article ID DIFFUSION FLAMES AB This paper addresses the behavior of a candle flame in a long-duration, quiescent microgravity environment both on the space Shuttle and the Mir Orbiting Station. On the Shuttle, the flames became dim blue after an initial transient where there was significant yellow (presumably soot) in the flame. The flame lifetimes were typically less than 60 seconds. The safety-mandated candlebox that contained the candle flame inhibited oxygen transport to the flame and thus limited the flame lifetime. The flames on the Mir were similar, except that the yellow luminosity persisted longer into the flame lifetime because of a higher initial oxygen concentration;The Mir flames burned for as long as 45 minutes. The difference in the flame lifetime between the Shuttle and Mir flames was primarily the redesigned candlebox that did not inhibit oxygen transport to the flame. In both environments, the flame intensity and the height-to-width ratio gradually decreased as the ambient oxygen content in the sealed chamber slowly decreased. Both sets of experiments showed spontaneous, axisymmetric flame oscillations just prior to extinction. The paper also presents a numerical model of a candle flame. The formulation is two-dimensional and time-dependent in the gas phase with constant specific heats, thermal conductivity and Lewis number (although different species can have different Lewis numbers), one-step finite-rate kinetics, and gas-phase radiative losses from CO2 and H2O. The treatment of the liquid/wick phase assumes that the fuel evaporates from a constant diameter sphere connected to an inert cone. The model predicts a steady flame with a shape and size quantitatively similar to the Shuttle and Mir flames. The computation predicts that the flame size will increase slightly with increasing ambient oxygen mole fraction. The model also predicts pre-extinction flame oscillations if the rate of decrease in ambient oxygen is small enough, such as that which would occur for a flame burning in a sealed ambient. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Cleveland, OH 44106 USA. RP Dietrich, DL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 20 TC 20 Z9 21 U1 3 U2 16 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2000 VL 156 BP 1 EP 24 DI 10.1080/00102200008947294 PG 24 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 333NL UT WOS:000088136100001 ER PT J AU Gokoglu, SA Schultz, DF AF Gokoglu, SA Schultz, DF TI A precise calibration technique for measuring high gas temperatures SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT 1st Mediterranean Combustion Symposium (MCS-99) CY JUN 20-25, 1999 CL ANTALYA, TURKEY SP Combust Inst, Int Ctr Heat & Mass Transfer DE diagnostics; measurement techniques; optical measurement; thermocouple measurement; flames; heat transfer and radiation ID FLAMES AB A technique was developed for direct measurements of gas temperatures in the range of 2050K-2700K with improved accuracy and reproducibility. The technique utilized the low-emittance of certain pure, metal-oxide fibers whose diameters varied from 60 - 400 mu m in the experiments. The uncertainty of the technique was limited by the uncertainty in the melting points of the materials, i.e., +/-15K. The abrupt increase in the emittance of the fibers upon melting was utilized as indication of reaching a known gas temperature. The accuracy of the technique was confirmed by both the fiber-diameter independence of the results and by the calculated low emittance values of transparent fibers, of order 0.01 at a few degrees below their melting point. This melting-point temperature was approached by increments smaller than 4K, accomplished by controlled increases of reactant flow rates in H-2/air or H-2/O-2 flames. As applications, the technique was used (a) for assessing the uncertainty in thermocouple measurements for inferring gas temperatures, and (b) for calibrating an IR camera to measure gas temperatures, thereby demonstrating its capability as an excellent calibration reference. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Gokoglu, SA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 17 TC 1 Z9 1 U1 0 U2 4 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PY 2000 VL 153 BP 3 EP + DI 10.1080/00102200008947247 PG 16 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 333NH UT WOS:000088135800002 ER PT J AU Aguirre, AA Balazs, GH AF Aguirre, AA Balazs, GH TI Blood biochemistry values of green turtles, Chelonia mydas, with and without fibropapillomatosis SO COMPARATIVE HAEMATOLOGY INTERNATIONAL LA English DT Article DE blood chemistry; Chelonia mydas; clinically normal; fibropapillomatosis; green turtle; Hawaiian Islands ID HAWAIIAN-ISLANDS; CARETTA-CARETTA; MARINE TURTLES; SEA-TURTLES; CHEMISTRY AB Baseline blood biochemistry values were obtained for two foraging aggregations of clinically healthy wild. juvenile green turtles (Chelonia mydas) inhabiting Kaneohe Bay, Island of Oahu, and the Kona Coast. Island of Hawaii. Mean reference values were compared to values obtained from green turtles of similar size affected with fibropapillomas (FP) collected at Kaneohe Bay, Statistically significant differences m;ere identified for total protein values, blued urea nitrogen, and enzyme values between healthy turtles and turtles with FP. In addition, turtles with severe FP were hypoproteinaemic, hypoalbuminaemic, hypoferraemic, azotaemic, and presented inverse calcium/phosphorus ratios, low cholesterol and triglyceride values, indicating the chronicity and severity of FP. It is concluded that blood reference values should be established for green turtles at the population level and by geographic area considering disease status, age, sex, and seasonal variations. C1 Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. Natl Marine Fisheries Serv, Honolulu Lab, Honolulu, HI USA. RP Aguirre, AA (reprint author), Ctr Conservat Med, Wildlife Trust, POB 1000,61 Route 9 W, Palisades, NY 10964 USA. NR 26 TC 39 Z9 42 U1 0 U2 16 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0938-7714 J9 COMP HAEMATOL INT JI Comp. Haematol. Int. PY 2000 VL 10 IS 3 BP 132 EP 137 DI 10.1007/s005800070004 PG 6 WC Hematology SC Hematology GA 427AV UT WOS:000168383400004 ER PT J AU Iyer, SK Lissenden, CJ Arnold, SM AF Iyer, SK Lissenden, CJ Arnold, SM TI Local and overall flow in composites predicted by micromechanics SO COMPOSITES PART B-ENGINEERING LA English DT Article DE inelastic flow; metal-matrix composites (MMCs); residual/internal stress; micromechanics; finite element analysis (FEA) ID METAL-MATRIX COMPOSITES; ELASTIC-PLASTIC BEHAVIOR; BORON ALUMINUM COMPOSITE; DOMINATED MODE; DAMAGE; VISCOPLASTICITY; DEFORMATION AB Rate-dependent inelastic flow in metal matrix composites subjected to multiaxial stress states is quantified by flow surfaces, which are geometrically analogous to yield surfaces. The definition of flow is important because the most meaningful definition from a theoretical viewpoint. dissipation, is not measurable in the laboratory. Inelastic power is measurable, but differs from the dissipation due to residual stresses and evolution of the material state. Since experiments are necessary for development and validation of models, both definitions are important and considered here. The relationship between local flow in the matrix and overall how of the composite is explored using finite element and generalized method of cells micromechanical analyses. The loci of how surfaces in the axial-transverse and transverse-transverse stress planes are plotted. At the threshold, the overall flow surface is the intersection of all the local flow surfaces. Beyond the threshold, the intersection of all the local flow surfaces is smaller than the overall flow surface and differences between the dissipation and inelastic power are notable. Most importantly, the directions of the overall inelastic strain rate vectors are generally not normal to the overall surface of constant dissipation after the material state has begun to evolve. Thus, an associative macroscale continuum model will be, at best, approximate, Interestingly, local flow surfaces beyond the threshold are not necessarily convex when plotted in the overall stress plane. This is due to the existence of residual stresses. In addition, the generalized method of cells was found to accurately estimate the inner and outer envelopes of the local flow surface cluster with a surprisingly small number of subcells. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Penn State Univ, Dept Engn Sci & Mech, University Pk, PA 16802 USA. Glenn Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Lissenden, CJ (reprint author), Penn State Univ, Dept Engn Sci & Mech, 227 Hammond Bldg, University Pk, PA 16802 USA. NR 36 TC 13 Z9 16 U1 0 U2 0 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 2000 VL 31 IS 4 BP 327 EP 343 DI 10.1016/S1359-8368(00)00011-1 PG 17 WC Engineering, Multidisciplinary; Materials Science, Composites SC Engineering; Materials Science GA 340XT UT WOS:000088562500008 ER PT J AU Noor, A Birman, V AF Noor, A Birman, V TI Untitled SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Editorial Material C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Computat Struct Technol, Hampton, VA 23681 USA. Univ Missouri, St Louis, MO 63121 USA. RP Noor, A (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Computat Struct Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PY 2000 VL 60 IS 15 BP 2757 EP 2758 DI 10.1016/S0266-3538(00)00142-1 PG 2 WC Materials Science, Composites SC Materials Science GA 374NP UT WOS:000165351500001 ER PT B AU Luo, LS AF Luo, LS BE Salas, MD Anderson, WK TI The future of lattice-gas and lattice Boltzmann methods SO COMPUTATIONAL AEROSCIENCES IN THE 21ST CENTURY SE ICASE/LARC INTERDISCIPLINARY SERIES IN SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT ICAS/LaRC/NSF/ARO Workshop on Computational Aerosciences in the 21st Century CY APR 22-24, 1998 CL HAMPTON, VA SP Inst Comp Applicat Sci & Engn, NASA Langley Res Ctr, Natl Sci Fdn, USA, Off Res ID NAVIER-STOKES EQUATION; SCHRODINGER-EQUATION; BOUNDARY-CONDITIONS; CELLULAR-AUTOMATA; CIRCULAR-CYLINDER; FLUID-FLOWS; MODEL; SIMULATION; SYSTEMS; MAGNETOHYDRODYNAMICS C1 NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23665 USA. RP Luo, LS (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23665 USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 66 TC 2 Z9 2 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6728-6 J9 ICASE LARC IN SCI EN PY 2000 VL 8 BP 165 EP 187 PG 23 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Engineering; Computer Science GA BS09G UT WOS:000168606200009 ER PT B AU Samareh, JA AF Samareh, JA BE Salas, MD Anderson, WK TI Geometry modeling and grid generation for design and optimization SO COMPUTATIONAL AEROSCIENCES IN THE 21ST CENTURY SE ICASE/LARC INTERDISCIPLINARY SERIES IN SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT ICAS/LaRC/NSF/ARO Workshop on Computational Aerosciences in the 21st Century CY APR 22-24, 1998 CL HAMPTON, VA SP Inst Comp Applicat Sci & Engn, NASA Langley Res Ctr, Natl Sci Fdn, USA, Off Res AB Geometry modeling and grid generation (GMGG) have played and will continue to play an important role in computational aerosciences. During the past two decades, tremendous progress has occurred in GMGG; however, GMGG is still the biggest bottleneck to routine applications for complicated Computational Fluid Dynamics (CFD) and Computational Structures Mechanics (CSM) models for analysis, design, and optimization. We are still far from incorporating GMGG tools in a design and optimization environment for complicated configurations. It is still a challenging task to parameterize an existing model in today's Computer-Aided Design (CAD) systems, and the models created are not always good enough for automatic grid generation tools. Designers may believe their models are complete and accurate, but unseen imperfections (e.g., gaps, unwanted wiggles, free edges, slivers, and transition cracks) often cause problems in gridding for CSM and CFD. Despite many advances in grid generation, the process is still the most labor-intensive and time-consuming part of the computational aerosciences for analysis, design, and optimization. In an ideal design environment, a design engineer would use a parametric model to evaluate alternative designs effortlessly and optimize an existing design for a new set of design objectives and constraints. For this ideal environment to be realized, the GMGG tools must have the following characteristics: (1) be automated, (2) provide consistent geometry across all disciplines, (3) be parametric, and (4) provide sensitivity derivatives. This paper will review the status of GMGG for analysis, design, and optimization processes, and it will focus on some emerging ideas that will advance the GMGG toward the ideal design environment. C1 NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23665 USA. RP Samareh, JA (reprint author), NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23665 USA. NR 35 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6728-6 J9 ICASE LARC IN SCI EN PY 2000 VL 8 BP 211 EP 229 PG 19 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Engineering; Computer Science GA BS09G UT WOS:000168606200011 ER PT B AU Schulbach, CH AF Schulbach, CH BE Salas, MD Anderson, WK TI NASA's Information Power Grid Project SO COMPUTATIONAL AEROSCIENCES IN THE 21ST CENTURY SE ICASE/LARC INTERDISCIPLINARY SERIES IN SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT ICAS/LaRC/NSF/ARO Workshop on Computational Aerosciences in the 21st Century CY APR 22-24, 1998 CL HAMPTON, VA SP Inst Comp Applicat Sci & Engn, NASA Langley Res Ctr, Natl Sci Fdn, USA, Off Res AB NASA's four Strategic Enterprises have bold goals that for achievement require orders-of-magnitude forward leaps in technology. Information systems technology is the key to enabling such breakthroughs, and so NASA is revolutionizing its approach to information technology with its Information Power Grid Project. "Information Power Grid" is NASA's term for its effort to seamlessly link all NASA resources - computers, data, instruments, and people - into an interdisciplinary problem-solving and decision-making environment. Information Power Grid is one of several computational grid efforts arising from: (1) the needs of organizations to make better use of their computational tools, and (2) the recognition that individual groups are using advances in software technology to develop sophisticated problem solving systems that are independent of each other. By recognizing the similarity in the underlying approaches to meeting these needs, a system (Information Power Grid) can be developed that provides an improved environment for resource management, while at the same time providing a uniform architecture for software development - from systems software (including security, resource management, etc.) to the domain applications. Plug-and-play capability will be available throughout the system, and users' problem solving abilities can focus on technologies other than information systems. Information Power Grid is now in the planning stage, and an overview of the effort is presented here. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Schulbach, CH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6728-6 J9 ICASE LARC IN SCI EN PY 2000 VL 8 BP 231 EP 242 PG 12 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications SC Engineering; Computer Science GA BS09G UT WOS:000168606200012 ER PT B AU Noor, AK AF Noor, AK BE Topping, BHV TI Pathway to the future of simulation and learning SO COMPUTATIONAL MECHANICS FOR THE TWENTY-FIRST CENTURY LA English DT Proceedings Paper CT 5th International Conference on Computational Structures Technology/2nd International Conference on Engineering Computational Technology CY SEP 06-08, 2000 CL LEUVEN, BELGIUM AB Key components of future simulation and learning environments are described. These components are needed for significantly enhancing the rapid creation of innovative affordable high-tech products. The simulation environment will link scientists, design teams, manufacturers, suppliers and consultants who participate in the creation and operation of high-tech products. It will use a synergistic combination of intelligent tools and facilities, advanced human-computer interfaces and non-classical methods, including multi-scale, highly coupled multi-physics and non-deterministic approaches. The three categories of learning environments required to meet the life-long learning demands of the future are described. These are expert-led group learning, self-paced individual learning, and collaborative learning. The three environments, in combination, can reduce the time and cost of learning, and sustain and increase worker competencies in high-tech organizations. C1 Univ Virginia, NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 22 TC 2 Z9 2 U1 0 U2 0 PU SAXE-COBURG PUBLICATIONS PI EDINBURGH PA 10 SAXE-COBURG PLACE, EDINBURGH EH3 5BR, SCOTLAND BN 1-874672-13-X PY 2000 BP 1 EP 22 PG 22 WC Computer Science, Interdisciplinary Applications; Engineering, Multidisciplinary; Mathematics, Applied SC Computer Science; Engineering; Mathematics GA BR36Y UT WOS:000166198200001 ER PT B AU Jeffries, DK Ferguson, F Chandra, S AF Jeffries, DK Ferguson, F Chandra, S BE Debnath, N TI Numerical simulation of high-speed flows over a complex vehicle geometry: An investigation of plume induced flow separation SO COMPUTER APPLICATIONS IN INDUSTRY AND ENGINEERING LA English DT Proceedings Paper CT 13th International Conference on Computer Applications in Industry and Engineering CY NOV 01-03, 2000 CL HONOLULU, HI SP Int Soc Comp & Their Applicat AB Aircraft, launch vehicles and missiles that travel at high altitudes have been observed to experience a phenomenon called Plume Induced Flow Separation (PIFS) during some portion of their flight path. Under certain flow conditions the exhaust plume from these vehicles will cause the external flow to separate from the vehicle's surface, allowing hot exhaust gases to recirculate into regions were they were not intended, like near engine components and vehicle surfaces. As a result, vehicle performance can be greatly affected. To investigate the effects of PIFS the vehicle must be operating under conditions that result in the phenomenon occurring, so that the resulting flowfield and thermal environment about the vehicle configuration can be observed and recorded for analysis. However, methods for analytically predicting PIFS in this manner are not available and are greatly needed. To investigate the effects of PIFS on an Atlas IIIA Launch Vehicle a numerical simulation of the vehicle during a portion of its flight when PIFS is likely to occur has been performed. The PIFS flowfield and thermal environment captured by the simulation will be used to predict the occurrence, extent, and effects of the phenomenon on the geometry of an Atlas IIIA vehicle. C1 N Carolina Agr & Tech State Univ, NASA, Coll Engn, Ctr Aerosp Res, Greensboro, NC 27411 USA. RP Jeffries, DK (reprint author), N Carolina Agr & Tech State Univ, NASA, Coll Engn, Ctr Aerosp Res, Greensboro, NC 27411 USA. NR 4 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 1-880843-35-8 PY 2000 BP 25 EP 27 PG 3 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Imaging Science & Photographic Technology SC Computer Science; Imaging Science & Photographic Technology GA BV53Q UT WOS:000179289300007 ER PT J AU Wasfy, TM Noor, AK AF Wasfy, TM Noor, AK TI Multibody dynamic simulation of the next generation space telescope using finite elements and fuzzy sets SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article DE multibody dynamics; spacefract; next-generation space telescope; finite elements; fuzzy sets; modeling and simulation; vibrational response; attitude control; deployment simulation ID SYSTEMS AB Multibody dynamic simulations are performed for a large deployable space structure using finite element models and an explicit temporal integration procedure. The structure considered is NASA's light-weight, 8 m-aperture next generation space telescope (NGST). The NGST structure consists of beam components (modeled using beam "super-elements", each composed of two truss elements and a torsional spring), thin-surface shell-type components (modeled using super-elements, each composed of one brick, twelve truss elements, and six surface elements), revolute and prismatic joints, and reaction wheels. Detailed numerical simulations are conducted for the vibrational response, attitude control, and deployment. A fuzzy-set technique is used to assess the effect of changing the dwell time of the Various deployment actuators on the total strain energy of the structure. Published by Elsevier Science S.A. All rights reserved. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 9 TC 8 Z9 11 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 190 IS 5-7 BP 803 EP 824 DI 10.1016/S0045-7825(99)00445-4 PG 22 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 380KK UT WOS:000165700900020 ER PT J AU Chien, YP Ecer, A Akay, HU Secer, S Blech, R AF Chien, YP Ecer, A Akay, HU Secer, S Blech, R TI Communication cost estimation for parallel CFD using variable time-stepping algorithms SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID FLUID-DYNAMICS PROBLEMS; COMPUTATION AB Variable time-stepping algorithm can greatly reduce the execution time of parallel CFD by allowing each parallel CFD process to select its own computation and communication time-steps according to the computational stability conditions. However. this algorithm significantly complicates the task of deriving the cost function for computer load balancing. Computer load balancing for parallel CFD requires a cost function that generally uses the elapsed CFD execution time as the cost. The cost function consists of three components: the computation cost the communication cost, and the idle cost. Since the execution of parallel CFD using variable time-stepping approach causes the change the load of of computer and network even in a single user environment, the cost function should be derived based on the measurement of the parallel CFD execution time. The derived cost function can be used for predicting the elapsed time of future program execution. In this paper, the derivation of communication cost function for a parallel CFD using variable time-stepping algorithm is described. The accuracy of the communication cost function is demonstrated by two test cases and has been successfully used in dynamic computer load balancing. (C) 2000 Elsevier Science S.A, All rights reserved. C1 Indiana Univ Purdue Univ, Dept Elect Engn, Purdue Sch Technol, Indianapolis, IN 46202 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chien, YP (reprint author), Indiana Univ Purdue Univ, Dept Elect Engn, Purdue Sch Technol, 723 W Michigan St, Indianapolis, IN 46202 USA. EM chien@engr.iupui.edu NR 16 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 190 IS 11-12 BP 1379 EP 1389 DI 10.1016/S0045-7825(00)00167-5 PG 11 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 386ZU UT WOS:000166096300005 ER PT J AU Xu, YL Noor, AK AF Xu, YL Noor, AK TI Perturbation mapping method for sensitivity analysis of three-dimensional cracks near a free surface SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article AB A perturbation mapping method and a computational procedure are presented for evaluating the sensitivity coefficients of the stress intensity factors for three-dimensional planar cracks near a free surface. The boundary integral equations for evaluating the sensitivity coefficient are solved by using the boundary element method. Each of the geometric parameters that affect the stress intensity factor (such as, crack orientation, distance from the free surface, and crack shape parameters) is given a perturbation which defines a mapping between the original and perturbed coordinate systems, from which the sensitivity coefficients are derived. The sensitivity coefficients obtained by the perturbation mapping method are validated by comparing them with those obtained by the finite difference method. Numerical results for penny-shaped and elliptical cracks are presented showing the variation of the sensitivity coefficients with various geometric and material parameters. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 189 IS 2 BP 613 EP 624 DI 10.1016/S0045-7825(99)00314-X PG 12 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 353PP UT WOS:000089284900014 ER PT J AU Meakin, RL AF Meakin, RL TI Adaptive spatial partitioning and refinement for overset structured grids SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID GENERATION AB The need for adaptive refinement for unsteady aerodynamic applications that may involve relative motion between configuration components is recognized. An efficient means of adaptive refinement within systems of overset structured grids is presented. Problem domains are segregated into near-body and off-body fields. Near-body fields are discretized via overlapping body-fitted grids that extend a short distance from body surfaces. Off-body fields are discretized via systems of overlapping uniform Cartesian (structured) grids of varying levels of refinement. A novel method of adaptive spatial partitioning and refinement that is responsive to evolving off-body flow dynamics and proximity of moving solid bodies is described. Computational advantages of structured data are reviewed. Properties of uniform Cartesian grids that lead to substantial computational advantages are identified. A grid component grouping algorithm is presented. Formal accuracy of the method is considered. The method is demonstrated for three-dimensional unsteady viscous flow applications of practical relevance. Published by Elsevier Science S.A. C1 NASA, Ames Res Ctr, Army NASA Rotocraft Div, US Army Aeroflightdynam DIrectorate,AMCOM, Moffett Field, CA 94035 USA. RP Meakin, RL (reprint author), NASA, Ames Res Ctr, Army NASA Rotocraft Div, US Army Aeroflightdynam DIrectorate,AMCOM, M-S 258-1, Moffett Field, CA 94035 USA. NR 38 TC 18 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 189 IS 4 BP 1077 EP 1117 DI 10.1016/S0045-7825(99)00369-2 PG 41 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 365CK UT WOS:000089930700003 ER PT J AU Argyris, JH Noor, AK Papadrakakis, M AF Argyris, JH Noor, AK Papadrakakis, M TI Recent advances and trends in composite materials and structures - Preface SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Editorial Material C1 Univ Stuttgart, Inst Comp Applicat, D-7000 Stuttgart, Germany. Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA USA. Natl Tech Univ Athens, Inst Struct Anal & Seism Res, Athens, Greece. RP Argyris, JH (reprint author), Univ Stuttgart, Inst Comp Applicat, D-7000 Stuttgart, Germany. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 185 IS 2-4 BP 91 EP 91 DI 10.1016/S0045-7825(99)00252-2 PG 1 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 314MA UT WOS:000087058700001 ER PT J AU Chamis, CC Murthy, PLN Gotsis, PK Mital, SK AF Chamis, CC Murthy, PLN Gotsis, PK Mital, SK TI Telescoping composite mechanics for composite behavior simulation SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article DE fiber composites; micromechanics; minimechanics; laminate theory; elemental scale; unit cell; hybrid composite; smart composites; finite element; progressive fracture; structural analysis; reinforced concrete; aging infrastructures; infrastructure enhancement; scale telescoping; scale substructuring; scale definition; computational simulation AB Telescoping composite mechanics are described and implemented in terms of recursive laminate theory. The initial elemental scale is defined where simple equations are derived. Subsequently these mechanics are applied to homogeneous composites, hybrid composites, smart composites and composite enhanced reinforced concrete structures. Results from those applications are presented in terms of tables/figures to illustrate the versatility and generality of telescoping composite mechanics. Comparisons with methods such as approximate, single cell, and 2D and 3D finite element demonstrate the predictive accuracy and computational effectiveness of composite telescoping mechanics. (C) 2000 Elsevier Science S.A. All rights reserved. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Univ Toledo, Toledo, OH 43606 USA. RP Chamis, CC (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 1 Z9 1 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 185 IS 2-4 BP 399 EP 411 DI 10.1016/S0045-7825(99)00268-6 PG 13 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 314MA UT WOS:000087058700017 ER PT J AU Noor, AK Starnes, JH Peters, JM AF Noor, AK Starnes, JH Peters, JM TI Uncertainty analysis of composite structures SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID REDUCED BASIS TECHNIQUE; PANELS AB A two-phase approach and a computational procedure are presented for predicting the variability in the nonlinear response of composite structures associated with variations in the geometric and material parameters of the structure. In the first phase, hierarchical sensitivity analysis is used to identify the major parameters, which have the most effect on the response quantities of interest. In the second phase, the major parameters are taken to be fuzzy parameters, and a fuzzy set analysis is used to determine the range of variation of the response, associated with preselected variations in the major parameters. The effectiveness of the procedure is demonstrated by means of a numerical example of a cylindrical panel with four T-shaped stiffeners and a circular cutout. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Noor, AK (reprint author), Univ Virginia, NASA, Langley Res Ctr, Ctr Adv Computat Technol, Mail Stop 201, Hampton, VA 23681 USA. NR 21 TC 24 Z9 24 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PY 2000 VL 185 IS 2-4 BP 413 EP 432 DI 10.1016/S0045-7825(99)00269-8 PG 20 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 314MA UT WOS:000087058700018 ER PT S AU van Katwijk, J Toetenel, H Sahraoui, AE Anderson, E Zalewski, J AF van Katwijk, J Toetenel, H Sahraoui, AE Anderson, E Zalewski, J BE Koornneef, F VanderMeulen, M TI Specification and verification of a safety shell with statecharts and extended timed graphs SO COMPUTER SAFETY, RELIABILITY AND SECURITY, PROCEEDINGS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 19th International Conference on the Reliability, Safety and Security of Critical Computer Application (SAFECOMP 2000) CY OCT 24-27, 2000 CL ROTTERDAM, NETHERLANDS ID SYSTEMS AB A new technique for applying safety principles, termed safety shell, eases the formal verification by segregation of the safety critical regions of the application into independent, well structured modules. This paper presents a practical use of formal methods for verification of the safety shell. A framework is proposed for the integration of semiformal and formal notations, in order to produce a formal specification on which verification tools can be applied. The approach relies on the following steps. The first step consists in using adequately statecharts and support tools to guide the analyst's understanding of the system and produce a preliminary document. In the second step an XTG-based specification is generated from the preliminary document on the basis of predefined rules. The third step then is to verify the specification w.r.t. relevant specified properties. Tool support is being developed to assist in the second step, while tool support for verification is available through the TVS toolset. C1 Delft Univ Technol, NL-2600 AJ Delft, Netherlands. Univ Calif Berkeley, PATH ITS, Berkeley, CA 94720 USA. Univ Cent Florida, Dept ECE, Orlando, FL 32816 USA. NASA, Kennedy Space Ctr, FL 32899 USA. RP Delft Univ Technol, NL-2600 AJ Delft, Netherlands. EM J.vanKatwijk@twi.tudelft.nl; w.j.toetenel@twi.tudelft.nl; kader@nt.path.berkeley.edu; Eric.Anderson-1@kmail.ksc.nasa.gov; jza@ece.engr.ucf.edu NR 21 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41186-0 J9 LECT NOTES COMPUT SC PY 2000 VL 1943 BP 37 EP 52 PG 16 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BU09R UT WOS:000175008000004 ER PT J AU Zrilic, DG Ramirez-Angulo, J Yuan, B AF Zrilic, DG Ramirez-Angulo, J Yuan, B TI Hardware implementations of fuzzy membership functions, operations, and inference SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article DE fuzzy logic; fuzzification; defuzzification; membership function; digital fuzzifier; current mode fuzzifier; transconductance multiplier; charge mode defuzzifier; Min and Max circuits ID BUILDING-BLOCKS AB In this paper, we propose several novel hardware circuits that can be used to design fuzzy logic systems. First, five different fuzzifying circuits,which can be easily embedded into other systems, are presented. Then, two novel defuzzifying schemes based on voltage and charge modes are introduced. Transconductance multipliers are employed to implement a voltage-mode defuzzifier while op amplifiers with floating gates are used to realize a charge-mode defuzzifier. Experimental results and layouts of fabricated chips are also presented. Finally, two novel designs of MIN and MAX circuits are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 New Mexico Highlands Univ, Dept Engn, NASA, Ctr Autonomous Control Engn, Las Vegas, NM 87701 USA. New Mexico State Univ, Klipsch Sch Elect & Comp Engn, Las Cruces, NM 88003 USA. Manning & Napier Informat Serv, Rochester, NY 14604 USA. RP New Mexico Highlands Univ, Dept Engn, NASA, Ctr Autonomous Control Engn, Las Vegas, NM 87701 USA. EM djuro@edison.nmhu.edu NR 16 TC 4 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7906 EI 1879-0755 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PD JAN PY 2000 VL 26 IS 1 BP 85 EP 105 DI 10.1016/S0045-7906(99)00025-7 PG 21 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 277AC UT WOS:000084909700007 ER PT J AU Pruett, CD Chang, CL Streett, CL AF Pruett, CD Chang, CL Streett, CL TI Simulation of crossflow instability on a supersonic highly swept wing SO COMPUTERS & FLUIDS LA English DT Article DE direct numerical simulation; parabolized stability equation methodology; high-speed civil transport; stationary crossflow instability; compressible flow; swept wing ID 3-DIMENSIONAL BOUNDARY-LAYERS; FLOW-VORTICES; TRANSITION; STABILITY; EVOLUTION AB A direct numerical simulation (DNS) algorithm has been developed for use in the investigation of crossflow instability on supersonic swept wings, an application of potential relevance to the design of the High-Speed Civil Transport (HSCT). The fully explicit algorithm exploits high-order compact-difference and spectral-collocation methods to solve the compressible Navier-Stokes equations in body-fitted coordinates. The method is applied to the investigation of stationary crossflow instability on an infinitely long 77-degree swept wing in Mach 3.5 flow. The results of the DNS are compared with the predictions of linear stability theory (LST) and linear parabolized stability equation (PSE) methodology. In general, the independently conducted DNS and PSE investigations agree closely in terms of the growth rate, the structure, and the orientation angle of the predicted stationary crossflow instability. Although further study is warranted for the case of large-amplitude (nonlinear) disturbances, the close agreement between the methods offers preliminary validation of both the DNS and PSE approaches for this application. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 James Madison Univ, Dept Math, Harrisonburg, VA 22807 USA. High Technol Corp, Hampton, VA 23666 USA. NASA, Flow Modeling & Control Branch, Langley Res Ctr, Hampton, VA 23681 USA. Coll William & Mary, Dept Appl Sci, Williamsburg, VA 23187 USA. RP Pruett, CD (reprint author), James Madison Univ, Dept Math, MSC 7803, Harrisonburg, VA 22807 USA. NR 38 TC 4 Z9 4 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JAN PY 2000 VL 29 IS 1 BP 33 EP 62 DI 10.1016/S0045-7930(98)00056-5 PG 30 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 245TT UT WOS:000083124800002 ER PT S AU Wilt, DM Clark, EB Clevenger, MB Murray, CS Wehrer, RJ AF Wilt, DM Clark, EB Clevenger, MB Murray, CS Wehrer, RJ GP IEEE IEEE TI 0.55eV n/p/n MIM TPV cell development SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc AB A monolithic interconnected module (MIM) has been described which serves as the photovoltaic converter and the spectral control mechanism in TPV devices. Current MIM development has been directed toward reducing the bandgap of the device to optimize the performance for low temperature radiators (similar to 1200K). Low bandgap (0.55eV) MIMs have been developed from InGaAs grown lattice mismatched to InP. A variety of buffer layer schemes have been investigated and the impact of buffer layer design on device performance has been examined. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Wilt, DM (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1024 EP 1027 DI 10.1109/PVSC.2000.916060 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900249 ER PT S AU Brinker, DJ Scheiman, DA AF Brinker, DJ Scheiman, DA GP IEEE IEEE TI Power degradation studies of the Mir solar array return experiment SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc AB A Russian solar array was recently returned from the Mir space station after 125 months on-orbit and made available to U.S. investigators for detailed post-flight analysis. The array, consisting of eight panels of silicon cells, was deployed on June 16, 1987 as one of four segments of an array located directly above the Kvant-2 module. After removal and packaging by Russian cosmonauts in November, 1997, it was brought back to Earth by the STS-89 mission two months later. Detailed post-flight performance measurements of one panel show that its overall power conversion efficiency degraded from a BOL value of about 9% to 4.8%, due not to an overall degradation in cell conversion efficiency but rather to circuit disruptions in several of the parallel connected strings. In this paper, the photovoltaic post-flight analysis will be presented, as well as a detailed description of the array technology. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Brinker, DJ (reprint author), NASA, Glenn Res Ctr, MS 302-1, Cleveland, OH 44135 USA. NR 1 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 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1071 EP 1074 DI 10.1109/PVSC.2000.916072 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900260 ER PT S AU Good, BS Chubb, DL Wolford, DS AF Good, BS Chubb, DL Wolford, DS GP IEEE IEEE TI Theoretical comparison of rare-earth garnet selective emitters SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc AB Spectral control through the use of selective emitters is an important means of improving the efficiency of thermophotovoltaic (TPV) systems. The rare-earth-aluminum garnet selective emitters developed in our laboratory offer a number of potential advantages for use in such systems [1-3]. In this paper, we present results of a detailed computational study of the effects of thermal gradients, along with some other film parameters, on the performance of three rare-earth-doped aluminum garnet selective emitters, specifically, Er3Al5O12, Ho3Al5O12, and Tm3Al5O12. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Good, BS (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1222 EP 1225 DI 10.1109/PVSC.2000.916109 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900297 ER PT S AU Raffaelle, RP Bailey, SG Neudeck, P Okojie, R Schnabel, CM Tabib-Azar, M Scheiman, D Jenkins, P Hubbard, S AF Raffaelle, RP Bailey, SG Neudeck, P Okojie, R Schnabel, CM Tabib-Azar, M Scheiman, D Jenkins, P Hubbard, S GP IEEE IEEE TI Optical and electrical characterization of SiC devices SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE Photovoltaic Specialists Conference LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc ID RECTIFIERS; BREAKDOWN AB The semiconductor SIC has long been known for its outstanding resistance to harsh environments (e.g., thermal stability, radiation resistance, dielectric strength). However, the ability to produce device quality material is severely limited by the inherent crystalline defects associated with this material and their associated electronic effects. Much progress has been made recently in the understanding and control of these defects and in the improved processing of this material. This work has made the possibility of producing SiC based solar cells for high-temperature, high-light intensity, and high-radiation missions, such as experienced by solar probes. In this paper, we will present our recent studies on defects in SiC and the synthesis and characterization SiC based solar cells. C1 Rochester Inst Technol, NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Raffaelle, RP (reprint author), Rochester Inst Technol, NASA Glenn Res Ctr, MS 302-1, Cleveland, OH 44135 USA. EM ryne.raffaelle@grc.nasa.gov; Sheila.Bailey@grc.nasa.gov; david.scheiman@grc.nasa.gov; phil.jenkins@grc.nasa.gov NR 11 TC 2 Z9 2 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-5772-8; 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1257 EP 1260 DI 10.1109/PVSC.2000.916118 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900306 ER PT S AU Landis, GA Jenkins, P Sexton, JA Scheiman, D Christie, R Charpie, J Gerber, SS Johnson, DB Bailey, SG AF Landis, GA Jenkins, P Sexton, JA Scheiman, D Christie, R Charpie, J Gerber, SS Johnson, DB Bailey, SG GP IEEE IEEE TI Photovoltaic Engineering Testbed - A facility for space calibration and measurement of solar cells on the International Space Station SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc AB The Photovoltaic Engineering Testbed ("PET") is a facility to be flown on the International Space Station to perform calibration, measurement, and qualification of solar cells in the space environment and then returning the cells to Earth for laboratory use. PET will allow rapid-turnaround testing of new photovoltaic technology under AM0 conditions. C1 NASA Glenn, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA Glenn, Ohio Aerosp Inst, 21000 Brookpk Rd,Mailstop 302-1, Cleveland, OH 44135 USA. NR 2 TC 1 Z9 1 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1352 EP 1353 DI 10.1109/PVSC.2000.916142 PG 2 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900330 ER PT S AU Stella, PM Davis, GL Mueller, RL Krut, DD Brinker, DJ Scheiman, DA AF Stella, PM Davis, GL Mueller, RL Krut, DD Brinker, DJ Scheiman, DA GP IEEE IEEE TI The performance of advanced solar cells for interplanetary missions SO CONFERENCE RECORD OF THE TWENTY-EIGHTH IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE - 2000 SE IEEE PHOTOVOLTAIC SPECIALISTS CONFERENCE LA English DT Proceedings Paper CT 28th IEEE Photovoltaic Specialists Conference CY SEP 15-22, 2000 CL ANCHORAGE, AK SP IEEE, IEEE Electron Device Soc AB Recent advances in space solar cell technology have produced substantial increases in Air Mass Zero (AM0) efficiency. Since these cells have been developed primarily for Earth orbiting missions, little is known of their behavior at distances far from the sun. In order to better define the photovoltaic performance of arrays for deep space missions, JPL has completed initial measurements on a number of advanced cells under a variety of LILT (low intensity, low temperature) conditions. These include high efficiency silicon, and multi- junction III-V devices. The test results show that multijunction cells suffer from LILT degradation and that at 5AU (approximately the solar distance of Jupiter), efficiency advantages over high efficiency silicon are minimal. Silicon cells optimized for 3-6 AU operation not only equal the efficiency available from 2 and 3 junction cells, but also tend to be more uniform. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stella, PM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0160-8371 BN 0-7803-5773-6 J9 IEEE PHOT SPEC CONF PY 2000 BP 1354 EP 1357 DI 10.1109/PVSC.2000.916143 PG 4 WC Energy & Fuels; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Energy & Fuels; Engineering; Materials Science GA BS98J UT WOS:000171592900331 ER PT S AU Truszkowski, W Karlin, J AF Truszkowski, W Karlin, J BE Klusch, M Kerschberg, L TI A cybernetic approach to the modeling of agent communities SO COOPERATIVE INFORMATION AGENTS IV: THE FUTURE OF INFORMATION AGENTS IN CYBERSPACE SE LECTURE NOTES IN ARTIFICIAL INTELLIGENCE LA English DT Article; Proceedings Paper CT 4th International Workshop on Cooperative Information Agents (CIA 2000) CY JUL 07-09, 2000 CL BOSTON, MASSACHUSETTS AB This paper, which is expository in nature, investigates and illustrates the idea of using cybernetic system modeling techniques to model a multi-agent community. The cybernetic concepts used are those originally developed by Stafford Beer. The paper illustrates the idea on a community of agents being developed at Goddard to support both ground-based and space-based system autonomy. It is hoped that use of this approach will help provide a deeper insight into the dynamics of agent-community behaviors. Time and additional analyses will tell. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Viable Syst Inc, Germantown, MD 20874 USA. RP Truszkowski, W (reprint author), NASA, Goddard Space Flight Ctr, Code 588, Greenbelt, MD 20771 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67703-8 J9 LECT NOTES ARTIF INT PY 2000 VL 1860 BP 166 EP 178 PG 13 WC Computer Science, Artificial Intelligence SC Computer Science GA BS61V UT WOS:000170571400016 ER PT S AU Doyle, RJ AF Doyle, RJ BE Klusch, M Kerschberg, L TI Inspiration for future autonomous space systems SO COOPERATIVE INFORMATION AGENTS IV: THE FUTURE OF INFORMATION AGENTS IN CYBERSPACE SE LECTURE NOTES IN ARTIFICIAL INTELLIGENCE LA English DT Article; Proceedings Paper CT 4th International Workshop on Cooperative Information Agents (CIA 2000) CY JUL 07-09, 2000 CL BOSTON, MASSACHUSETTS C1 CALTECH, Jet Prop Lab, Ctr Space Mission Informat & Software Syst, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Informat Technol & Software Syst Div, Pasadena, CA 91109 USA. RP Doyle, RJ (reprint author), CALTECH, Jet Prop Lab, Ctr Space Mission Informat & Software Syst, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67703-8 J9 LECT NOTES ARTIF INT PY 2000 VL 1860 BP 244 EP 246 PG 3 WC Computer Science, Artificial Intelligence SC Computer Science GA BS61V UT WOS:000170571400022 ER PT S AU Brittnacher, M Wilber, M Fillingim, M Chua, D Parks, G Spann, J Germany, G AF Brittnacher, M Wilber, M Fillingim, M Chua, D Parks, G Spann, J Germany, G BE Russell, CT TI Global auroral response to a solar wind pressure pulse SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID SUBSTORMS AB A global intensification of the aurora was observed by the Ultraviolet Imager on the NASA Polar spacecraft in conjunction with the arrival of the sheath from a solar coronal mass ejection. The aurora was first observed to brighten on the dayside and then the intensification progressed rapidly toward the nightside. During this time the IMP-8 spacecraft in the solar wind recorded a 35-minute period of increased solar wind dynamic pressure. A small substorm (or, possibly pseudobreakup) occurred within a minute of the arrival of the auroral intensification on the nightside in conjunction with a second peak in the dynamic pressure. We propose that the intensification of the aurora can be explained on the basis of the compression of the magnetopause and the generation of hydromagnetic waves by the rapid increase in the solar wind dynamic pressure. It is also evident that the substorm was triggered by waves, generated by a second rise in the dynamic pressure, that propagated to flux tubes connected to the premidnight auroral region. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Univ Washington, Geophys Program, Seattle, WA 98195 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Univ Alabama, CSPAR, Huntsville, AL 35899 USA. RP Brittnacher, M (reprint author), Univ Washington, Geophys Program, Seattle, WA 98195 USA. NR 17 TC 24 Z9 25 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1377 EP 1385 DI 10.1016/S0273-1177(99)00647-X PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400011 ER PT S AU Kanekal, SG Baker, DN Blake, JB Klecker, B Mason, GM Mewaldt, RA AF Kanekal, SG Baker, DN Blake, JB Klecker, B Mason, GM Mewaldt, RA BE Russell, CT TI Magnetospheric relativistic electron response to magnetic cloud events of 1997. SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID ACCELERATION; SOLAR; PARTICLES; SAMPEX; INNER; ISTP; WIND AB Relativistic electron flux enhancements in the outer zone, resulting from the interaction of the magnetosphere with magnetic cloud(Coronal Mass Ejection) events during 1997 have been studied using sensors aboard multiple spacecraft. It is found that the relativistic flux enhancements in the outer zone show a great degree of coherence that is very nearly independent of pitch angle, L-shell and energy. Enhancements occur over a broad range of L suggesting the global nature of the underlying acceleration mechanisms. In addition, the rapid rise times of the electron fluxes, being about less than a day or so, imply that these processes are of a non-adiabatic nature. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS, Greenbelt, MD USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Aerospace Corp, El Segundo, CA 90245 USA. Max Planck Inst, Garching, Germany. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. CALTECH, Pasadena, CA 91125 USA. RP Kanekal, SG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. OI Klecker, Berndt/0000-0001-8337-5120 NR 16 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1387 EP 1392 DI 10.1016/S0273-1177(99)00648-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400012 ER PT S AU Takeuchi, T Araki, T Lepping, RP Mukai, T Saito, Y Kokubun, S Yamamoto, T Nagai, T Iyemori, T AF Takeuchi, T Araki, T Lepping, RP Mukai, T Saito, Y Kokubun, S Yamamoto, T Nagai, T Iyemori, T BE Russell, CT TI A magnetic cloud with unusual structure and bow shock movement observed on May 13, 1995 SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID IMP-8 OBSERVATIONS; WIND; SHAPE AB A magnetic cloud embedded in a corotating interaction region was observed by WIND 244 Re upstream of Earth on May 13, 1995. This cloud was unusual since it had at least two internal structures and the profile of the magnetic field strength did not conform to a simple force-free flux rope model, though the held direction fitted well. About 90 min later, it was detected by IMP 8 and GEOTAIL in front of Earth's bow shock. GEOTAIL observed a sunward movement of the bow shock 8 min after the passage of the front boundary. From the normal vector of the bow shock front, we deduce that the shape of the expanding bow shock was distorted from an axially symmetric geometry. The shape was consistent with distortion due to the observed inclination of the front boundary of the magnetic cloud. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Kyoto Univ, Dept Geophys, Kyoto, Japan. NASA, GSFC, Greenbelt, MD 20771 USA. ISAS, Sagamihara, Kanagawa, Japan. Nagoya Univ, STE Lab, Nagoya, Aichi, Japan. Tokyo Inst Technol, Tokyo, Japan. Kyoto Univ, DACGSM, Kyoto, Japan. RP Takeuchi, T (reprint author), Kyoto Univ, Dept Geophys, Kyoto, Japan. NR 9 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1397 EP 1400 DI 10.1016/S0273-1177(99)00650-X PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400014 ER PT S AU Wuest, M Huddleston, MM Burch, JL Dempsey, DL Craven, PD Chandler, MO Spann, JF Peterson, WK Collin, HL Lennartsson, W AF Wuest, M Huddleston, MM Burch, JL Dempsey, DL Craven, PD Chandler, MO Spann, JF Peterson, WK Collin, HL Lennartsson, W BE Russell, CT TI Magnetospheric response to the arrival of the shock wave in front of the magnetic cloud of January 10, 1997 SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res AB We are studying the magnetic cloud of January 6-11, 1997. Specifically, we have investigated the response of the magnetosphere to the shock front ahead of the magnetic cloud on January 10, 1997 using data from Wind, Geotail and Polar spacecraft as well as ground magnetometer data. The Wind spacecraft, which was located at about 85 Re upstream from the Earth at (85.1, -55.2, -22.1) Re-GSM, observed the arrival of the shock wave front at 0052 UT. Geotail was located at the equatorial magnetopause (similar to 8.7 Re, 10.7 MLT, -7.46 MLAT), while Polar was located in the northern dawn sector above the auroral zone at 8.4 Re, 6.1 MLT and 61.1 MLAT. A magnetic signature was nearly simultaneously observed at about 0105 UT at the Polar and Geotail spacecraft. The Geotail spacecraft entered from the magnetosphere into the magnetosheath. Particle density increases were observed on Wind and Geotail, but not on Polar. Two instruments on the Polar spacecraft (TIDE and TIMAS) actually observed a slight reduction in energy, density and temperature. The UV aurora shows a dawnside intensification. The shock wave did not cause an auroral substorm and therefore was not geoeffective. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 SW Res Inst, San Antonio, TX 78228 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35899 USA. Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. RP Wuest, M (reprint author), SW Res Inst, 6220 Culebra Rd, San Antonio, TX 78228 USA. RI Peterson, WK/A-8706-2009 OI Peterson, WK/0000-0002-1513-6096 NR 7 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 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1401 EP 1404 DI 10.1016/S0273-1177(99)00651-1 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400015 ER PT S AU Erkaev, NV Farrugia, CJ Biernat, HK Ogilvie, KW Quinn, JM AF Erkaev, NV Farrugia, CJ Biernat, HK Ogilvie, KW Quinn, JM BE Russell, CT TI Magnetosheath parameters near the subsolar line predicted by an MHD flow model with anisotropic pressure SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID PLASMA DEPLETION LAYER; EARTHS MAGNETOSHEATH; CLOSURE; REGION AB We extend our "magnetic string" MHD model describing the flow of the shocked solar wind around the magnetosphere to include an anisotropic plasma pressure with p(perpendicular to) > p(parallel to). Thermodynamic properties are determined by the law of conservation of energy of a magnetic string associated with a magnetic field line. The MHD equations are closed by a relation between p(perpendicular to) and p(parallel to) corresponding to the threshold of the electromagnetic proton cyclotron wave instability. Assuming no flow across the magnetopause, we compare profiles of the steady-state magnetic field and plasma parameters along the subsolar line for upstream sonic and Alfven Mach numbers = 10 with the isotropic case (p(perpendicular to) = p(parallel to)). In the anisotropic model, besides the density, both temperatures, plasma pressures and betas decrease toward the magnetopause. The temperature and plasma pressure parallel to the magnetic field decrease more strongly than those perpendicular to the field. Profiles for temperature and pressure in the case of isotropy lie between those of corresponding parallel and perpendicular values, but closer to the latter. The gradient of B near the magnetopause is larger than for isotropic pressure. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Russian Acad Sci, Inst Computat Modelling, Krasnoyarsk 660036 36, Russia. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Osterreich Akad Wikssensch, Inst Weltraumforsch, A-8042 Graz, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Erkaev, NV (reprint author), Russian Acad Sci, Inst Computat Modelling, Krasnoyarsk 660036 36, Russia. RI Erkaev, Nikolai/M-1608-2013 OI Erkaev, Nikolai/0000-0001-8993-6400 NR 18 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1523 EP 1528 DI 10.1016/S0273-1177(99)00665-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400029 ER PT S AU Fujimoto, M Mukai, T Matsuoka, A Saito, Y Hayakawa, H Kokubun, S Lepping, RP AF Fujimoto, M Mukai, T Matsuoka, A Saito, Y Hayakawa, H Kokubun, S Lepping, RP BE Russell, CT TI Multi-point observations of cold-dense plasma sheet and its relation with tail-LLBL SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID LATITUDE BOUNDARY-LAYER; INTERPLANETARY MAGNETIC-FIELD; EARTHS MAGNETOSPHERE; SOLAR-WIND; CONVECTION; NORTHWARD; MAGNETOTAIL; CURRENTS; MODEL; FLOW AB Following the suggestion that the low-latitude boundary layer (LLBL) in the near-Earth magnetotail can be the site of capturing magnetosheath plasma into the plasma sheet during extended northward IMF periods, we have made a case study of the plasma sheet using data from WIND, Geotail and Akebono. On Feb. 9-10, 1995, IMF was northward for more than 24 hours. The plasma sheet at (X-gsm, Y-gsm) = (-30 similar to -15,0 similar to -10)R-e observed by Geotail changed its status from hot-tenuous to cold-dense in this period. The ions in the cold-dense plasma sheet have two characteristic energies (temperatures) just as those in the LLBL. The colder component had a temperature as low as a few hundreds eV. From Akebono observations during the same time interval, the convection pattern in the high-latitude ionosphere was found to show a clear four-cell structure. Although these facts are well-known on statistical basis, the simultaneous observations definitely put a constraint that the plasma transport which produces the cold-dense plasma sheet should be in accord with the four-cell convection pattern. Inspection on the Akebono particle data shows that a few keV ion/soft (< 1 keV) electron precipitation are seen in the sunward convection zone located adjacent to the trapped particle region at invariant latitudes of 75 degrees similar to 80 degrees. Discussion on the formation of the cold-dense plasma sheet, during northward IMF period is made on the basis of these observations. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Tokyo Inst Tech, Dept Earth Planet Sci, Meguro Ku, Tokyo 1528551, Japan. Inst Space & Astronaut Sci, Kanagawa 229, Japan. Nagoya Univ, STEL, Aichi 442, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fujimoto, M (reprint author), Tokyo Inst Tech, Dept Earth Planet Sci, Meguro Ku, Tokyo 1528551, Japan. NR 13 TC 10 Z9 12 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1607 EP 1616 DI 10.1016/S0273-1177(99)00674-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400038 ER PT S AU Kawano, H Nakamura, R Kokubun, S Mukai, T Yamamoto, T Yumoto, K Slavin, JA AF Kawano, H Nakamura, R Kokubun, S Mukai, T Yamamoto, T Yumoto, K Slavin, JA BE Russell, CT TI Substorm-associated shrinkage of the mid-tail magnetosphere: IACG Campaign #2 SO COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Int Union Geodesy & Geophys, Int Assoc Geomagnetism & Aeron, Comm Space Res ID NEAR-EARTH; MAGNETOPAUSE; INSTRUMENT; ISEE-3; SHAPE AB In the framework of IACG Campaign #2, we study a case in which the GEOTAIL spacecraft was close to the mid-tail magnetopause when three substorms took place. GEOTAIL was mainly located within the dawnside plasmasheet, and its average speed normal to the nominal magnetopause was very small (similar to 0.2 R-E/hr) because it was near its apogee. It exited to the LLBL similar to magnetosheath during the expansion to recovery phases of each substorm, stayed there for a while, and then returned to the plasmasheet near the end of the recovery phase. This pattern suggests a shrinkage of the mid-tail magnetosphere after the expansion onset so that the tail radius becomes smaller than that in the quiet time. We interpret it as a result of strong tailward flows from the near-Earth neutral line which transports plasma in the mid-tail region to the distant tail and causes a rarefaction in the mid-tail region. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Kyushu Univ, Dept Earth & Planetary Sci, Fukuoka 812, Japan. Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Kawano, H (reprint author), Kyushu Univ, Dept Earth & Planetary Sci, Fukuoka 812, Japan. RI Slavin, James/H-3170-2012; Nakamura, Rumi/I-7712-2013 OI Slavin, James/0000-0002-9206-724X; Nakamura, Rumi/0000-0002-2620-9211 NR 19 TC 0 Z9 0 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 7/8 BP 1689 EP 1696 DI 10.1016/S0273-1177(99)00685-7 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57W UT WOS:000085558400049 ER PT S AU Muglach, K Fleck, B Schuhle, U Stolpe, F Foing, BH Wilhelm, K AF Muglach, K Fleck, B Schuhle, U Stolpe, F Foing, BH Wilhelm, K BE Watanabe, T Schwenn, R TI Dynamics of chromospheric and transition region lines observed with SOHO/SUMER and the GCT/Tenerife SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res AB High-resolution spectroscopic observations of the quiet Sun have been carried out in September 1996 at the German Gregory Coude Telescope (GCT) in Tenerife and in May 1997 with the SUMER instrument onboard SOHO. Time sequences of spectra in the visible and near infrared as well as in the ultraviolet have been taken, covering a range of heights from the solar photosphere up into the transition region. In this contribution we present the dynamical behaviour observed at the various heights in the solar atmosphere. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 European Space Agcy, Estec, Dept Space Sci, NL-2201 Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Greenbelt, MD 20771 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Sternwarte Gottingen, D-37083 Gottingen, Germany. RP Muglach, K (reprint author), European Space Agcy, Estec, Dept Space Sci, Kepleraan 1, NL-2201 Noordwijk, Netherlands. RI Fleck, Bernhard/C-9520-2012 NR 3 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 J9 ADV SPACE RES PY 2000 VL 25 IS 9 BP 1731 EP 1734 DI 10.1016/S0273-1177(99)00620-1 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100003 ER PT S AU Schmieder, B Deng, Y Mandrini, CH Rudawy, P Nitta, N Mason, H Fletcher, L Martens, P Brynildsen, N AF Schmieder, B Deng, Y Mandrini, CH Rudawy, P Nitta, N Mason, H Fletcher, L Martens, P Brynildsen, N BE Watanabe, T Schwenn, R TI Dynamics in restructuring active regions observed during SOHO/YOHKOH/GBO campaigns SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res ID H-ALPHA SURGES AB JOP17 and JOP 33 are SOHO Joint Observing Programs in collaboration with Yohkoh/SXT and ground based observatories (GBO's), dedicated to observe dynamical events through the atmosphere. During runs of these programs we observed in restructuring active regions (ARs), surges, subflares, bright knots, but not large flares and jets. From these observations we have been able to derive some of the responses of the coronal and chromospheric plasma to the evolution of the photospheric magnetic field. Emerging flux in an AR led to the formation of Arch Filament Systems in the chromosphere, hot loops and knots in the transition region, and X-ray loops. Frequent surges have been observed in relation to parasitic or mixed polarities, but coronal jets have not yet been found. We discuss the possible mechanisms acting during the restructuring of the active regions (reconnection or "sea-serpent" geometries). (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Observ Paris, F-92195 Meudon, France. Inst Oslo, N-0315 Oslo 3, Norway. Chinese Acad Sci, Beijing Astron Observ, Beijing 100080, Peoples R China. Inst Astron & Fis Espacio, RA-1428 Buenos Aires, DF, Argentina. Univ Wroclaw, Inst Astron, PL-51622 Wroclaw, Poland. Lockheed, Palo Alto, CA 94304 USA. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Schmieder, B (reprint author), Observ Paris, F-92195 Meudon, France. NR 8 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 J9 ADV SPACE RES PY 2000 VL 25 IS 9 BP 1879 EP 1882 DI 10.1016/S0273-1177(99)00600-6 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100035 ER PT S AU Usmanov, AV Besser, BP Fritzer, JM Goldstein, ML AF Usmanov, AV Besser, BP Fritzer, JM Goldstein, ML BE Watanabe, T Schwenn, R TI Simulation of a coronal streamer: Alfven wave acceleration SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res ID SOLAR-WIND; ULYSSES AB A self-consistent simulation of the plasma flow in a dipole-like magnetic field configuration is performed. The features of the present formulation are: incorporation of the heat and momentum addition due to WKB Alfven waves propagating outward from the Sun and providing additional acceleration to the coronal plasma how; extension of the computational domain out to 1 AU. The governing dissipationless single-fluid MHD equations are solved in the equatorial plane of the spherical coordinate system. In agreement with Ulysses observations, the results of simulation demonstrate (i) absence of a marked gradient in the radial magnetic field distribution across the polar high-velocity stream, (ii) the velocity does not change considerably in this stream, but slightly increases toward its center, (iii) the momentum flux density is higher over the pole than near the equator, while the mass flux density shows a slight increase toward the equator. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Usmanov, AV (reprint author), St Petersburg State Univ, Inst Phys, St Petersburg 198904, Russia. RI Goldstein, Melvyn/B-1724-2008; Usmanov, Arcadi/A-9860-2013 NR 8 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 J9 ADV SPACE RES PY 2000 VL 25 IS 9 BP 1897 EP 1900 DI 10.1016/S0273-1177(99)00613-4 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100039 ER PT S AU Ofman, L DeForest, CE AF Ofman, L DeForest, CE BE Watanabe, T Schwenn, R TI Numerical simulations of trapped slow magnetosonic waves in solar coronal plumes SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res ID POLAR PLUMES; TELESCOPE; HOLES; WIND AB Recent observations of polar plumes in the southern solar coronal hole by the Extreme ultraviolet Imaging Telescope (EIT) on board the SOHO spacecraft show signatures of quasi-periodic compressional waves. Here, we present the results of a nonlinear, 2D MHD simulation of the slow magnetosonic waves in plumes for typical coronal conditions consistent with observations. Our numerical simulations confirm the interpretation of the observed intensity fluctuations as propagating slow magnetosonic waves. On March 7 1996 Deforest and Gurman (1998) detected quasi-periodic intensity variations of 10-20% in the EIT fe I); and X line emission at 171 Angstrom that propagate outward in several polar plumes at 75-150 km s(-1) with a period of 10-15 minutes. The observed propagation velocity agrees well with the expected sound velocity inside the plumes. The lower phase speed in the plumes than in the ambient plasma leads to partial trapping of the slow magnetosonic waves in the plumes. The slow magnetosonic waves may contribute to the heating of the lower corona by compressive dissipation. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Raytheon STX, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Greenbelt, MD 20771 USA. RP Ofman, L (reprint author), Raytheon STX, 682, Greenbelt, MD 20771 USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 9 BP 1909 EP 1912 DI 10.1016/S0273-1177(99)00622-5 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100042 ER PT S AU Orlando, S Khan, J Van Driel-Gesztelyi, L Thompson, B Fludra, A Foing, B AF Orlando, S Khan, J Van Driel-Gesztelyi, L Thompson, B Fludra, A Foing, B BE Watanabe, T Schwenn, R TI Large-scale evolution of the active region NOAA 7978, 7981, 7986 observed by GOES, SOHO, and Yohkoh SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res ID X-RAY MEASUREMENTS AB We took part in a joint project aimed to study the large-scale evolution of an active region from its emergence throughout its decay for several solar rotations. Our interest focuses on the understanding of how energy is generated, released, deposited, and transformed in active, regions. To this end, we determined physical parameters like intensity, temperature, and emission measure of the whole active region as a function of time for the entire period selected. We present the preliminary results of the analysis of GOES (Geosynchronous Operational Environmental Satellite), SOHO (Solar and Heliospheric Observatory) and Yohkoh data of the active region named NOAA 7978, 7981, and 7986 observed between July and October 1996. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 European Space Agcy, Estec, Dept Space Sci, Solar Syst Div, NL-2200 AG Noordwijk, Netherlands. UCL, Mullard Space Sci Lab, London WC1E 6BT, England. Konkoly Observ Budapest, H-1525 Budapest, Hungary. Observ Paris, DASOP, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rutherford Appleton Lab, Div Astrophys, Didcot OX11 0QX, Oxon, England. RP Orlando, S (reprint author), European Space Agcy, Estec, Dept Space Sci, Solar Syst Div, NL-2200 AG Noordwijk, Netherlands. RI Thompson, Barbara/C-9429-2012; OI Orlando, Salvatore/0000-0003-2836-540X NR 6 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2000 VL 25 IS 9 BP 1913 EP 1916 DI 10.1016/S0273-1177(99)00623-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100043 ER PT S AU Mobius, E Gloeckler, G Goldstein, B Habbal, S McNutt, R Randolph, J Title, A Tsurutani, B AF Mobius, E Gloeckler, G Goldstein, B Habbal, S McNutt, R Randolph, J Title, A Tsurutani, B BE Watanabe, T Schwenn, R TI Here comes solar probe! SO CORONAL STRUCTURE AND DYNAMICS NEAR SOLAR ACTIVITY MINIMUM SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2 Symposium of COSPAR Scientific Commission E Held during the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Inst Space & Astronaut Sci, European Space Agcy, NASA, Russian Space Agcy, Comm Space Res AB Despite recent advances, fundamental questions remain about the nature of the solar corona and the solar wind: 1) What heats the corona and accelerates the solar wind? 2) Where do the different types of solar wind originate? 3) Where and how are energetic particles produced and transported near the Sun? 4) What role do plasma turbulence and waves play in the corona and solar wind production? 5) What is the nature of the magnetic field and photospheric structures near the solar poles? Flying a trajectory perpendicular to the Earth-Sun line during its perihelion passage, Solar Probe will use in-situ and imaging instruments to provide the first three dimensional viewing of the corona, direct observations of solar polar regions, and local sampling of the solar environment. These primary observations are complemented by context-setting measurements and Earth-based observations. Solar Probe is currently scheduled for launch in February 2007 as the third in the new Outer Planets/Solar Probe mission line of NASA and will arrive at the Sun in 2010 under solar maximum conditions with a second closest approach near solar minimum in 2015. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Univ New Hampshire, Ctr Space Sci, Durham, NH USA. Univ Maryland, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Lockheed Martin Adv Technol Lab, Palo Alto, CA 94304 USA. RP Mobius, E (reprint author), Univ New Hampshire, Ctr Space Sci, Durham, NH USA. RI McNutt, Ralph/E-8006-2010; OI McNutt, Ralph/0000-0002-4722-9166; Moebius, Eberhard/0000-0002-2745-6978 NR 11 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 9 BP 1961 EP 1964 DI 10.1016/S0273-1177(99)00610-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP67C UT WOS:000085822100053 ER PT S AU Fishman, GJ AF Fishman, GJ BE Holt, SS Zhang, WW TI Gamma-ray burst observations SO COSMIC EXPLOSIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID 28 FEBRUARY 1997; HIGH-ENERGY; BATSE; AFTERGLOW; IDENTIFICATION; EMISSION; FLUENCE AB Gamma-ray bursts (GRBs) are the most luminous known objects in the Universe. Their brief, random appearance in the gamma-ray region had made their study difficult since their discovery, over thirty years ago. There is a rich diversity in the duration and morphology of GRB time profiles. The spectra are characterized by a smooth continuum, usually peaking in the range from similar to 0.1 MeV to 1 MeV. The recent discovery of counterparts to gamma-ray bursts and afterglow radiation in other wavelengths has provided the long-sought breakthrough in the direct determination of their distance and luminosity. Delayed gamma-ray burst photons extending to GeV energies have been detected. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Fishman, GJ (reprint author), NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Code SD 50, Huntsville, AL 35812 USA. NR 28 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 179 EP 189 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100023 ER PT S AU Gehrels, N Macomb, D AF Gehrels, N Macomb, D BE Holt, SS Zhang, WW TI Gamma ray bursts: The future SO COSMIC EXPLOSIONS SE AIP Conference Proceedings LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID 28 FEBRUARY 1997; AFTERGLOW; LOCATIONS; SYSTEM; BATSE AB Gamma-ray bursts are the most dramatic and powerful cosmic explosions known. They also continue to be the most puzzling. Thanks to breakthrough observations over the last decade, however, a picture has emerged of gamma-ray bursts being at cosmological distances and capable of releasing more than 10(51) ergs of energy within seconds. Despite the emergence of this picture, the physical origin of bursts is still unknown and the classification of different types of bursts is still in its infancy. Further understanding of gamma-ray bursts requires the wise use of our current resources and the development of new observational capabilities. We outline the current state of our knowledge of bursts and describe the present and future instrumentation which will enable us to understand these baffling blasts. C1 Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM gehrels@gsfc.nasa.gov; macomb@cossc.gsfc.nasa.gov RI Zhang, William/D-3535-2012; Gehrels, Neil/D-2971-2012 NR 37 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 227 EP 236 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100026 ER PT S AU Kazanas, D Mastichiadis, A AF Kazanas, D Mastichiadis, A BE Holt, SS Zhang, WW TI The proton-photon instability model for GRBs SO COSMIC EXPLOSIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID ACTIVE GALACTIC NUCLEI; RELATIVISTIC OUTFLOWS; ORIGIN; BLAZARS AB We propose that an instability based on the upstream reflection and reinterception of synchrotron radiation, produced in a relativistically moving blast wave, can convert the kinetic energy of its constituent protons to an e(+) - e(-) plasma, on time scales comparable to the light crossing time of the blast wave thickness, much in the way proposed to occur in the relativistic jets of AGN. For sufficiently large values of the blast wave Lorentz factor Gamma > Gamma(c), this process can proceed without the existence of an accelerated population of protons on the shock frame. The value of r, depends on the value of magnetic field on the blast wave frame Bo (Gauss) and it is given by Gamma(c) similar to 600B(0)(-1/5), in reasonable agreement with current estimates of the values of these parameters. The resulting e(+) - e(-) pairs have a Lorentz factor similar to Gamma(c) and therefore produce synchrotron and IC radiation with peak emission at frequencies proportional to B(0)Gamma(c)(2), B(0)Gamma(c)(4) respectively. In in the lab frame, the IC peak emission is preceived at a frequency B(0)Gamma(c)(5) similar or equal to 1 providing a possible account for the observed energy distribution of GRBs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 261 EP 264 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100033 ER PT S AU Swank, JH AF Swank, JH BE Holt, SS Zhang, WW TI Observations of Type I bursts from neutron stars SO COSMIC EXPLOSIONS SE AIP Conference Proceedings LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID X-RAY-BURSTS; MILLISECOND PULSAR; SPECTRA AB Observations of Type I X-ray bursts have long been taken as evidence that the sources are neutron stars. Black body models approximate the spectral data and imply a suddenly heated neutron star cooling over characteristic times of seconds to minutes. The phenomena are convincingly explained in terms of nuclear burning of accreted gas on neutron stars with low mass companion stars. Prospects are promising that detailed theory and data from RXTE and future missions will lead to better determinations of important physical parameters (neutron star mass and radius, composition of the accreting gas, distance of the source). Among the variety of bursts observed, there are probably representatives of different kinds of explosive burning. RXTE's discovery of a 2.5 ms persistent coherent period from one Type I burster has now linked bursters indisputably to the epitome of a neutron star, a fast spinning magnetic compact object. Oscillations in some bursts had already been thought to arise from the neutron stars' rotations. Detailed observations of these oscillations are touchstones of how the explosive bursts originate and progress, as well as independent measures of the neutron star parameters. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM swank@lheamail.gsfc.nasa.gov NR 25 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 349 EP 358 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100044 ER PT S AU Strohmayer, TE AF Strohmayer, TE BE Holt, SS Zhang, WW TI Phase resolved spectroscopy of burst oscillations: Searching for rotational Doppler shifts SO COSMIC EXPLOSIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID X-RAY-BURSTS; BRIGHTNESS OSCILLATIONS AB X-ray brightness oscillations with frequencies from 300 - 600 Hz have been observed in six low mass X-ray binary (LMXB) bursters with the Rossi X-ray Timing Explorer (RXTE). These oscillations likely result from spin modulation of a hot region on the stellar surface produced by thermonuclear burning. If this hypothesis is correct the rotational velocity of the stellar surface, approximate to 0.1 c, will introduce a pulse phase dependent Doppler shift such that the rising edge of a pulse should be harder (blue shifted) than the trailing edge (red shifted). Detection of this effect would both provide further compelling evidence for the spin modulation hypothesis as well as providing new observational techniques with which to constrain the masses and radii of neutron stars. In this work I present results of an attempt to search for such Doppler shifts. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Mail Code 662, Greenbelt, MD 20771 USA. RI Zhang, William/D-3535-2012 NR 10 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 375 EP 378 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100047 ER PT S AU Ramaty, R Mandzhavidze, N AF Ramaty, R Mandzhavidze, N BE Holt, SS Zhang, WW TI High energy processes in solar flares SO COSMIC EXPLOSIONS SE AIP Conference Proceedings LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland ID GAMMA-RAY SPECTROSCOPY; PARTICLE-ACCELERATION; INTERSTELLAR-MEDIUM; ABUNDANCES; LINE; RATIO; EMISSIONS; MISSION; MAXIMUM AB We review the highlights of the high energy processes in solar flares. Particle acceleration is an essential ingredient of the flare energy release process. Among all cosmic high energy sources, hares are unique in that both the accelerated particle and the radiations that they produce are observed. In this paper we emphasize the radiations, gyrosynchrotron emission, bremsstrahlung and gamma ray lines. These provide information on flare models, magnetic fields, energy content in the accelerated particles and abundances. The abundances are not only critical for constraining the acceleration mechanisms, but also provide unique information on solar atmospheric dynamics and mixing, solar wind acceleration, and Galactic chemical evolution. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM ramaty@gsfc.nasa.gov NR 59 TC 2 Z9 2 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 401 EP 410 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100051 ER PT S AU Gull, TR Davidson, K Ishibashi, K AF Gull, TR Davidson, K Ishibashi, K BE Holt, SS Zhang, WW TI Eta Carinae: The iron curtain lifts! SO COSMIC EXPLOSIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 10th Annual Astrophysics Conference on Cosmic Explosions CY OCT 11-13, 1999 CL COLLEGE PK, MD SP Univ Maryland AB Observations of Eta Carinae and the surrounding ejecta nebulae were done with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) during the past two years using a 52 " x 0.1 " aperture and gratings with R approximate to 4000 - 8000. In March 1998 and February 1999 complete coverage of the spectrum from 1640 Angstrom to 10400 Angstrom was accomplished at the same position angle. Not only did Eta Carinae brighten in that interval by 60 percent, but also the nebulosities within the central two arcseconds changed considerably. Most notable is the overall decrease in [Fe II] emissions and Fe II absorptions with increases in doubly-ionized ionic emissions including [Fe III]. At this time, we do not know if the changes are due to a 5.5 year cyclic variation or an overall brightening of Eta Carinae. Continued monitoring with STIS is planned for the near future and proposals are submitted for the full 5.5 year spectroscopic cycle. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gull, TR (reprint author), Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 8 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-943-2 J9 AIP CONF PROC PY 2000 VL 522 BP 439 EP 442 DI 10.1016/B978-012305560-6/50014-9 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ55Z UT WOS:000088762100056 ER PT B AU Zehavi, I Dekel, A AF Zehavi, I Dekel, A BE Courteau, S Strauss, MA Willick, JA TI Cosmological parameters and power spectrum from peculiar velocities SO COSMIC FLOWS 1999: TOWARDS AN UNDERSTANDING OF LARGE-SCALE STRUCTURE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Workshop on Cosmic Flows: Towards an Understanding of Large-Scale Structure CY JUL 13-17, 1999 CL UNIV VICTORIA, VICTORIA, CANADA SP Herzberg Inst Astrophys, Canadian Inst Theoret Astrophys HO UNIV VICTORIA ID SUPERNOVAE; UNIVERSE AB The power spectrum of mass density fluctuations is evaluated from the Mark III and the SFI catalogs of peculiar velocities by a maximum likelihood analysis, using parametric models for the power spectrum and for the errors. The applications to the two different data sets, using generalized CDM models with and without COBE normalization, give consistent results. The general result is a relatively high amplitude of the power spectrum, with sigma(8)Omega(m)(0.6) = 0.8 +/- 0.2 at 90% confidence. Casting the results in the Omega(m) - Omega(Lambda) plane yields complementary constraints to those of the high-redshift supernovae, together favoring a nearly fiat, unbound and accelerating universe with comparable contributions from Omega(m) and Omega(Lambda). Further implications on the cosmological parameters, arising from a joint analysis of the velocities together with small-scale CMB anisotropies and the high-redshift supernovae, are also briefly described. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Grp, Batavia, IL 60510 USA. RP Zehavi, I (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Grp, Box 500, Batavia, IL 60510 USA. NR 14 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 1-58381-028-5 J9 ASTR SOC P PY 2000 VL 201 BP 262 EP 269 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ38S UT WOS:000088225500038 ER PT B AU Shaya, E Peebles, PJE Phelps, S Tully, RB AF Shaya, E Peebles, PJE Phelps, S Tully, RB BE Courteau, S Strauss, MA Willick, JA TI Mass-to-light ratio measurements of galaxies, groups, and clusters using the numerical action method SO COSMIC FLOWS 1999: TOWARDS AN UNDERSTANDING OF LARGE-SCALE STRUCTURE SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Workshop on Cosmic Flows: Towards an Understanding of Large-Scale Structure CY JUL 13-17, 1999 CL UNIV VICTORIA, VICTORIA, CANADA SP Herzberg Inst Astrophys, Canadian Inst Theoret Astrophys HO UNIV VICTORIA ID LEAST ACTION PRINCIPLE; LOCAL GROUP; GRAVITATIONAL-INSTABILITY; NEARBY GALAXIES; ORBITS AB The numerical action variational method (NAM) is an elegant, non-chaotic technique for calculating the trajectories of gravitating systems in a cosmological context. It has been used extensively for establishing orbits of Local Group galaxies in a series of papers (Peebles 1989, 1990, 1994, 1995) and for the Local Supercluster (Shaya, Peebles, & Tully 1995). Our repertoire of tools include code that holds present distances constant and predicts possible redshifts, one that holds present redshifts constant and predicts possible distances, and one that varies masses of each mass tracer and simultaneously satisfies both distance and redshift. Our results indicate a Omega(0) = 0.2, a mass-to-light ratio of field galaxies in the range of 100 M./L. in blue light (t(0) = 11 Gyr with no cosmological constant), but for the Virgo Cluster, the value is 6 or 7 times higher. The higher values of Omega(0) determined from using the IRAS galaxy distributions may be a result of under weighting this important mass component of the universe plus a poor correlation between cluster and field galaxy distributions. C1 NASA, RITSS, Washington, DC 20546 USA. RP Shaya, E (reprint author), NASA, RITSS, Washington, DC 20546 USA. NR 15 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 1-58381-028-5 J9 ASTR SOC P PY 2000 VL 201 BP 352 EP 359 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ38S UT WOS:000088225500054 ER PT S AU Suess, ST AF Suess, ST BE Kunow, H Smith, EJ Marsden, RG TI The sun and the solar wind close to the sun SO COUPLING OF THE HIGH AND LOW LATITUDE HELIOSPHERE AND ITS RELATION TO THE CORONA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 7 Symposium of COSPAR Scientific Commission D held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res ID CORONAL MASS EJECTIONS; RADIAL IMF COMPONENT; MAGNETIC-FIELD; LATITUDINAL DEPENDENCE; ULYSSES OBSERVATIONS; UVCS OBSERVATIONS; WHITE-LIGHT; STREAMERS; PLUMES; MODEL AB One of the benefits of the Ulysses, SOHO, and YOHKOH missions has been a strong stimulus to better understand the magnetohydrodynamic processes involved in coronal expansion. Three topics for which this has been especially true are described here. These are: (i) The observed constancy of the radial interplanetary magnetic field strength (as mapped to constant radius). (ii) The geometric spreading of coronal plumes and coronal holes, and the fate of plumes. (iii) The plasma beta in streamers and the physics of streamer confinement. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Suess, ST (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Stop SD50, Huntsville, AL 35812 USA. NR 41 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 J9 ADV SPACE RES PY 2000 VL 26 IS 5 BP 761 EP 770 DI 10.1016/S0273-1177(00)00003-X PG 10 WC Engineering, Aerospace SC Engineering GA BQ23G UT WOS:000087680000001 ER PT S AU Breen, AR De Forest, CF Thompson, BJ McKenzie, JF Modigliani, A Moran, PJ Williams, PJS AF Breen, AR De Forest, CF Thompson, BJ McKenzie, JF Modigliani, A Moran, PJ Williams, PJS BE Kunow, H Smith, EJ Marsden, RG TI Comparisons of interplanetary scintillation and optical measurements of solar wind acceleration with model results SO COUPLING OF THE HIGH AND LOW LATITUDE HELIOSPHERE AND ITS RELATION TO THE CORONA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 7 Symposium of COSPAR Scientific Commission D held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res ID EISCAT AB Observations of the fast, high latitude solar wind show that acceleration of the fast wind is complete by 10 solar radii (R), while measurements from the LASCO instrument on SOHO show that most of the acceleration takes place inside 5 R. A series of observations were made in September 1997 using EISCAT and the C2 and C3 coronagraphs aboard SOHO to measure the solar wind velocity profile from 3 R out to beyond 30 R. The overlapping fields of view of the instruments allowed direct comparisons to be made between IFS and optical estimations of flow velocity. Together, these measurements provide strong constraints on any model seeking to provide an explanation of the acceleration of the fast solar wind. We present the results of a comparison between out observations and the most recent version of the Lindau-Warsaw solar wind acceleration model. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. Univ Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. RP Breen, AR (reprint author), Univ Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. RI Thompson, Barbara/C-9429-2012 NR 22 TC 5 Z9 5 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 26 IS 5 BP 781 EP 784 DI 10.1016/S0273-1177(00)00005-3 PG 4 WC Engineering, Aerospace SC Engineering GA BQ23G UT WOS:000087680000003 ER PT S AU Smith, EJ Balogh, A Forsyth, RF Tsurutani, BT Lepping, RP AF Smith, EJ Balogh, A Forsyth, RF Tsurutani, BT Lepping, RP BE Kunow, H Smith, EJ Marsden, RG TI Recent observations of the heliospheric magnetic field at Ulysses: Return to low latitude SO COUPLING OF THE HIGH AND LOW LATITUDE HELIOSPHERE AND ITS RELATION TO THE CORONA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 7 Symposium of COSPAR Scientific Commission D held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res ID SOLAR-WIND; CURRENT SHEET; SCAN; 1-AU AB Ulysses recently completed a second slow latitude scan of the northern heliosphere, a descent from 80.2 degrees N in July 1995 to the solar equator in December 1997. These recent magnetic field observations complement those from the south hemisphere and reveal new features as well as the effect of the changing solar cycle. Five topics are emphasized in this report. (1) The solar wind latitude structure is affected by the low inclination of the heliospheric current sheet (HCS) which prevents fast high latitude wind ti om reaching down into the ecliptic and leads to three distinct zones, the middle or transition zone consisting of large periodic Corotating Interaction Regions (CIRs). The HCS is first observed in the middle zone at unexpectedly high latitudes. (2) In the Corotating Rarefaction Regions (CRRs) separating the CIRs, a large discrepancy is found between the observed and Parker spiral angles with the field being underwound by approximate to 30 degrees. (3) Fluctuations in the field are again predominantly Alfven waves in the fast wind so that the variances undergo periodic variations in level in the transition zone. (4) The magnetic flux parameter, r(2)B(R) differs in the three zones being constant at high latitudes, enhanced in mid- and depleted at low- latitudes. The observations are consistent with displacement of magnetic flux from low to mid-latitudes. (5) An asymmetry between the radial components in the south and north hemispheres is evident in observations being made in the ecliptic by WIND. The observations agree with a southward displacement of the HCS as inferred from the Ulysses cosmic ray measurements. A time variation during the fast latitude scan from the south to the north pole obscured this asymmetry in the Ulysses magnetic field measurements. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, EJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 19 Z9 19 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 26 IS 5 BP 823 EP 832 DI 10.1016/S0273-1177(00)00014-4 PG 10 WC Engineering, Aerospace SC Engineering GA BQ23G UT WOS:000087680000012 ER PT S AU Posner, A Bothmer, V Kunow, H Gosling, JT Heber, B Lazarus, AJ Linker, JA Marsden, RG Mikic, Z Muller-Mellin, R Sanderson, TR Szabo, A Thompson, BJ AF Posner, A Bothmer, V Kunow, H Gosling, JT Heber, B Lazarus, AJ Linker, JA Marsden, RG Mikic, Z Muller-Mellin, R Sanderson, TR Szabo, A Thompson, BJ BE Kunow, H Smith, EJ Marsden, RG TI Energetic particle signatures of a corotating interaction region from a high latitude coronal hole: SOHO, wind and Ulysses observations SO COUPLING OF THE HIGH AND LOW LATITUDE HELIOSPHERE AND ITS RELATION TO THE CORONA SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 7 Symposium of COSPAR Scientific Commission D held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP Comm Space Res ID EIT AB In mid 1996 the Comprehensive Suprathermal and Energetic Particle Analyser (COSTEP) onboard the Solar and Heliospheric Observatory, at 1 AU in the ecliptic plane, detected recurrent periods of enhanced MeV ions in association with a corotating interaction region (CIR). Measurements of energetic ions from the Cosmic Ray and Solar Particle Instrument/Low Energy Telescope (COSPIN/LET) onboard Ulysses taken at 5 AU, at mid-northern heliographic latitudes, showed that Ulysses encountered recurrent particle events during the same time period. We used the solar wind speeds observed at both locations to estimate the corresponding solar source longitudes of the particle events. These longitudes are related to warps of the Sun's large high latitude northern coronal hole boundaries observed by SOHO's Extreme Ultraviolet Imaging Telescope (EIT). The findings are supported by three-dimensional magnetohydrodynamic (MHD) calculations of the footpoint positions of the magnetic field lines at both spacecraft. The observations suggest that close to the Sun a superradial expansion of the fast solar wind from the Sun's high latitude northern coronal hole down to ecliptic latitudes is present. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Univ Kiel, IEAP, Kiel, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CEA, DSM, DAPNIA, Serv Astrophys, Gif Sur Yvette, France. MIT, Cambridge, MA 02139 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. European Space Agcy, Estec, NL-2200 AG Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Posner, A (reprint author), Univ Kiel, IEAP, Olshaussenstr 40, Kiel, Germany. RI Thompson, Barbara/C-9429-2012; OI Posner, Arik/0000-0003-1572-8734 NR 16 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 26 IS 5 BP 865 EP 870 DI 10.1016/S0273-1177(00)00020-X PG 6 WC Engineering, Aerospace SC Engineering GA BQ23G UT WOS:000087680000018 ER PT S AU Robinson, DW AF Robinson, DW BE Fischer, RE Johnson, RB Smith, WJ Swantner, WH TI Minimizing gravity sag of a large mirror with an inverted Hindle-mount SO CURRENT DEVELOPMENTS IN LENS DESIGN AND OPTICAL SYSTEMS ENGINEERING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Current Developments in Lens Design and Optical Systems Engineering CY AUG 02-04, 2000 CL SAN DIEGO, CA SP SPIE DE Hindle mount; optical; mounting; techniques; bonding; epoxy; cell AB A method of minimizing the optical distortion from gravity sag on a suspended large autocollimating flat mirror has been devised. This method consists of an inverted nine-point Hindle-Mount. A conventional Hindle-Mount is located underneath a sky-viewing mirror and is primarily under compression loads from the weight of the mirror. It is not suitable for the situation where the mirror is viewing the ground, since a mirror would tend to fall out of the mount when in an inverted position. The inverted Hindle-Mount design consists of bonded joints on the backside of the mirror that allow the mirror to be held or suspended above an object to be viewed. This ability is useful in optical setups such as a calibration test where a flat mirror is located above a telescope so that the telescope may view a known optic. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Robinson, DW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 6 TC 3 Z9 4 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3738-7 J9 P SOC PHOTO-OPT INS PY 2000 VL 4093 BP 142 EP 150 DI 10.1117/12.405200 PG 3 WC Optics SC Optics GA BR14Z UT WOS:000165734700015 ER PT S AU Huegele, VB AF Huegele, VB BE Fischer, RE Johnson, RB Smith, WJ Swantner, WH TI Optical design of SHASM: Segmented hexagon array solar mirror SO CURRENT DEVELOPMENTS IN LENS DESIGN AND OPTICAL SYSTEMS ENGINEERING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Current Developments in Lens Design and Optical Systems Engineering CY AUG 02-04, 2000 CL SAN DIEGO, CA SP SPIE DE segmented mirror array; spherical approximation; solar thermal propulsion; solar power AB A segmented array of mirrors was designed for a solar concentrator test stand at MSFC for firing solar thermal propulsion engines. The 144 mirrors each have a spherical surface to approximate a parabolic concentrator when combined into the entire 17-foot diameter array. The mirror segments are aluminum hexagons that had the surface diamond turned and quartz coated. The array focuses sunlight reflected from a heliostat to a 4 inch diameter spot containing 8 kilowatts of power at the 15 foot focal point. The derivation of the surface figure for the respective mirror elements is shown. The alignment process of the array is discussed and test results of the system's performance are given. C1 NASA, George C Marshall Space Flight Ctr, SOMTC, Huntsville, AL 35812 USA. RP Huegele, VB (reprint author), NASA, George C Marshall Space Flight Ctr, SOMTC, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3738-7 J9 P SOC PHOTO-OPT INS PY 2000 VL 4093 BP 333 EP 339 DI 10.1117/12.405223 PG 3 WC Optics SC Optics GA BR14Z UT WOS:000165734700037 ER PT J AU Burge, HA Pierson, DL Groves, TO Strawn, KE Mishra, SK AF Burge, HA Pierson, DL Groves, TO Strawn, KE Mishra, SK TI Dynamics of airborne fungal populations in a large office building SO CURRENT MICROBIOLOGY LA English DT Article ID EPIDEMIOLOGY; FIBERGLASS; ENDOTOXIN AB The increasing concern, with bioaerosols in large office buildings prompted this prospective study of airborne fungal concentrations in a newly constructed building on the Gulf coast. We collected volumetric culture plate air samples on 14 occasions over the 18-month period immediately following building occupancy. On each sampling occasion, we collected duplicate samples from three sites on three floors nf this six-story building and an outdoor sample. Fungal concentrations indoors were consistently below those outdoors, and no sample clearly indicated fungal contamination in the building, although visible growth appeared in the ventilation system during the course of the study. We conclude that modern mechanically ventilated buildings prevent the intrusion of most of the outdoor fungal aerosol, and that even relatively extensive air sampling protocols may not sufficiently document the microbial status of buildings. C1 Harvard Univ, Sch Publ Hlth, Boston, MA 02115 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Enterprise Advisory Serv Inc, Houston, TX USA. Kelsey Seybold Clin, Ind Hyg Sect, Houston, TX USA. Univ Space Res Assoc, Houston, TX 77058 USA. RP Burge, HA (reprint author), Harvard Univ, Sch Publ Hlth, 665 Huntington Ave, Boston, MA 02115 USA. NR 14 TC 50 Z9 50 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0343-8651 J9 CURR MICROBIOL JI Curr. Microbiol. PD JAN PY 2000 VL 40 IS 1 BP 10 EP 16 DI 10.1007/s002849910003 PG 7 WC Microbiology SC Microbiology GA 260WK UT WOS:000083976300003 PM 10568797 ER PT S AU Serabyn, E AF Serabyn, E BE Schurmann, B TI Experimental confirmation of deep nulling SO DARWIN AND ASTRONOMY, PROCEEDINGS: THE INFRARED SPACE INTERFEROMETER SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Darwin and Astronomy: The Infrared Space Interferometer CY NOV 17-19, 1999 CL STOCKHOLM, SWEDEN SP Swedish Natl Space Board, European Space Agcy, Stockholm Univ, Stockholm Observ, Alcatel Space Ind, Saab Ericsson Space, Stockholm Stad, Stockholm City Council, Swedish Space Corp, Volvo Aero Corp, CASA DE nulling interferometry; rotational shearing interferometer ID PLANETS; INTERFEROMETER; LIFE AB Nulling interferometry has great potential ill the search for planetary companions and exozodiacal disks, but the various approaches proposed remain largely unproven. Here laboratory confirmation of deep nulling is reported. Using a filer-coupled rotational shearing interferometer, a red laser diode has been nulled to a part, in several hundred thousand, and the laser null has been stabilized to a part in 10,000. Single-polarization white light of 10% bandwidth has also been nulled to a part in 10,000. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Serabyn, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 171-113, Pasadena, CA 91109 USA. NR 16 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 92-9092-645-7 J9 ESA SP PUBL PY 2000 VL 451 BP 101 EP 105 PG 3 WC Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BQ50T UT WOS:000088542400015 ER PT S AU Beichman, CA AF Beichman, CA BE Schurmann, B TI Nasa's terrestrial planet finder (TPF) SO DARWIN AND ASTRONOMY, PROCEEDINGS: THE INFRARED SPACE INTERFEROMETER SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Darwin and Astronomy: The Infrared Space Interferometer CY NOV 17-19, 1999 CL STOCKHOLM, SWEDEN SP Swedish Natl Space Board, European Space Agcy, Stockholm Univ, Stockholm Observ, Alcatel Space Ind, Saab Ericsson Space, Stockholm Stad, Stockholm City Council, Swedish Space Corp, Volvo Aero Corp, CASA C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Beichman, CA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 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 92-9092-645-7 J9 ESA SP PUBL PY 2000 VL 451 BP 239 EP 244 PG 4 WC Astronomy & Astrophysics; Instruments & Instrumentation; Optics SC Astronomy & Astrophysics; Instruments & Instrumentation; Optics GA BQ50T UT WOS:000088542400034 ER PT S AU Burl, MC Lucchetti, D AF Burl, MC Lucchetti, D BE Dasarathy, BV TI Autonomous visual discovery SO DATA MINING AND KNOWLEDGE DISCOVERY: THEORY, TOOLS, AND TECHNOLOGY II SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Data Mining and Knowledge Discovery - Theory, Tools, and Technology II CY APR 24-25, 2000 CL ORLANDO, FL SP SPIE DE visual discovery; image mining; scientific datasets; focus of attention; salience; defects; outlier detection; geological features; planetary exploration ID INSPECTION; ATTENTION; VISION; MODEL AB This paper describes a prototype visual discovery algorithm that is designed to identify regions of an image that differ significantly from the local background. Image regions are projected into a visually-relevant, subspace using a set of multi-orientation, multi-scale Gabor filters that model the receptive field properties of simple cells in the human visual cortex. Within this filter response subspace, deviant areas are identified through an adaptive statistical test that compares the filter-space description of a region against a model derived from the local background. Deviant regions are then spatially agglomerated and grouped across scale. Experimentation on a variety of archived imagery collected by JPL spacecraft and ground-based telescopes shows that the algorithm is able to autonomously "rediscover" a number of important geological objects such as impact craters, volcanoes, sand dunes, and ice geysers that are known to be of interest to planetary scientists. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, MS 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Michael.C.Burl@jpl.nasa.gov NR 23 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3683-6 J9 PROC SPIE PY 2000 VL 4057 BP 240 EP 248 DI 10.1117/12.381738 PG 9 WC Computer Science, Artificial Intelligence; Optics SC Computer Science; Optics GA BQ36J UT WOS:000088122800026 ER PT J AU Marra, J Trees, CC Bidigare, RR Barber, RT AF Marra, J Trees, CC Bidigare, RR Barber, RT TI Pigment absorption and quantum yields in the Arabian Sea SO DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY LA English DT Article ID PHYTOPLANKTON; COEFFICIENTS; GROWTH; LIGHT; PHOTOSYNTHESIS; SYNECHOCOCCUS; SYSTEM; OCEAN AB Carbon assimilation and optical properties were measured at several stations in the Arabian Sea, during the Spring Intermonsoon (March-April 1995) and the Northeast Monsoon (December 1995), Biological measurements, as a function of depth (z), included: (14)C uptake (P), total daily (photosynthetically active) irradiance (E(PAR)), spectral irradiance, spectral absorption by phytoplankton, and a variety of HPLC-determined phytoplankton pigments. Phytoplankton absorption (a(ph)) was optically weighted to the spectral quality of submarine irradiance. Absorption spectra based on particulates collected on filters were compared with spectra reconstructed from phytoplankton pigments. These two methods generally agreed, except in the blue region of the spectrum at intermediate and shallow depths. Quantum yield (phi, on a daily basis) was estimated by non-linear regression from the relationship, P(z)/(a) over bar(ph)(z) = phi(E(PAR))E(PAR)(z). Absorption by non-photosynthetic pigments in most cases causes a decrease in maximum realized quantum yield ranging from 30% to a factor of four. Generally, stations, with higher non-photosynthetic pigment absorption had lower maximum quantum yields but a greater ability to utilize high irradiances. The data suggest the hypothesis that adaptation, through absorption properties, is the primary determinant of the magnitude of photosynthetic quantum yield in phytoplankton. (C) 2000 Elsevier Science Ltd, All rights reserved. C1 NASA Headquarters, Oceanog Program Off Earth Sci Code YS, Washington, DC 20546 USA. San Diego State Univ, Ctr Hydroopt & Remote Sensing, San Diego, CA 92120 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. Duke Univ, Marine Lab, Beaufort, NC 28516 USA. RP Marra, J (reprint author), NASA Headquarters, Oceanog Program Off Earth Sci Code YS, Room SP33,300 E St SW, Washington, DC 20546 USA. EM jmarra@mail.hq.nasa.gov NR 33 TC 24 Z9 27 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0645 J9 DEEP-SEA RES PT II JI Deep-Sea Res. Part II-Top. Stud. Oceanogr. PY 2000 VL 47 IS 7-8 BP 1279 EP 1299 DI 10.1016/S0967-0645(99)00144-7 PG 21 WC Oceanography SC Oceanography GA 297LU UT WOS:000086085000004 ER PT B AU Hadaegh, FY Mesbahi, M AF Hadaegh, FY Mesbahi, M BE Quevedo, J Escobet, T TI Optimal control strategies for imaging using formation flying spacecraft SO DIGITAL CONTROL: PAST, PRESENT AND FUTURE OF PID CONTROL SE IFAC WORKSHOP SERIES LA English DT Proceedings Paper CT IFAC Workshop on Digital Control - Past, Present and Future of PID Control (PID 00) CY APR 05-07, 2000 CL TERRASSA, SPAIN SP Int Federat Automat Control, Tech Comm Control Design DMC, Tech Comm Linear Syst DML, Univ Politecn Catalunya, Automat Control Dept DE optical interferometry; uv-plane coverage; optimal control; combinatorial optimization AB We delineate on the optimal control strategies for the uv-plane coverage and the associated combinatorial optimization problems. The results are represented in the context of the separated spacecraft optical interferometry ST3 mission. Copyright (C) 2000 IFAC. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hadaegh, FY (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 PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND BN 0-08-043624-2 J9 IFAC WORK S PY 2000 BP 361 EP 366 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic; Mathematics, Applied SC Automation & Control Systems; Engineering; Mathematics GA BS87X UT WOS:000171311800057 ER PT S AU Atkins, HL AF Atkins, HL BE Cockburn, B Karniadakis, GE Shu, CW TI Steps toward a robust high-order simulation tool for aerospace applications SO DISCONTINUOUS GALERKIN METHODS: THEORY, COMPUTATION AND APPLICATIONS SE LECTURE NOTES IN COMPUTATIONAL SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT 1st International Symposium on Discontinuous Galerkin Methods CY MAY 24-26, 1999 CL NEWPORT, RI SP Natl Sci Fdn, US DOE, USA, Army Res Off AB The discontinuous Galerkin method is seemingly immune to many of the problems that commonly plague high-order finite-difference methods, and as such, has the potential to bring the robustness of low-order methods and the efficiency of high-order methods to bear on a broad class of engineering problems. However the dependence of the method on numerical quadrature has significantly increased the cost of the method and limited the use of the method to element shapes for which quadrature formulas are readily available. A quadrature-free formulation has been proposed that allows the discontinuous Galerkin method to be implemented for any element shape and for polynomial basis functions of any degree. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Atkins, HL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 1439-7358 BN 3-540-66787-3 J9 LECT NOTES COMP SCI PY 2000 VL 11 BP 53 EP 61 PG 9 WC Engineering, Multidisciplinary; Mathematics, Applied; Mechanics; Physics, Mathematical SC Engineering; Mathematics; Mechanics; Physics GA BR11S UT WOS:000165694700002 ER PT S AU Barth, TJ AF Barth, TJ BE Cockburn, B Karniadakis, GE Shu, CW TI Simplified discontinuous Galerkin methods for systems of conservation laws with convex extension SO DISCONTINUOUS GALERKIN METHODS: THEORY, COMPUTATION AND APPLICATIONS SE LECTURE NOTES IN COMPUTATIONAL SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT 1st International Symposium on Discontinuous Galerkin Methods CY MAY 24-26, 1999 CL NEWPORT, RI SP Natl Sci Fdn, US DOE, USA, Army Res Off AB Simplified forms of the space-time discontinuous Galerkin (DG) and discontinuous Galerkin least-squares (DGLS) finite element method are developed and analyzed. The new formulations exploit simplifying properties of entropy endowed conservation law systems while retaining the favorable energy properties associated with symmetric variable formulations. C1 NASA, Ames Res Ctr, Informat Sci Directorate, Moffett Field, CA 94035 USA. RP Barth, TJ (reprint author), NASA, Ames Res Ctr, Informat Sci Directorate, Moffett Field, CA 94035 USA. NR 10 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 1439-7358 BN 3-540-66787-3 J9 LECT NOTES COMP SCI PY 2000 VL 11 BP 63 EP 75 PG 13 WC Engineering, Multidisciplinary; Mathematics, Applied; Mechanics; Physics, Mathematical SC Engineering; Mathematics; Mechanics; Physics GA BR11S UT WOS:000165694700003 ER PT S AU Greenstadt, J AF Greenstadt, J BE Cockburn, B Karniadakis, GE Shu, CW TI An abridged history of cell discretization SO DISCONTINUOUS GALERKIN METHODS: THEORY, COMPUTATION AND APPLICATIONS SE LECTURE NOTES IN COMPUTATIONAL SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT 1st International Symposium on Discontinuous Galerkin Methods CY MAY 24-26, 1999 CL NEWPORT, RI SP Natl Sci Fdn, US DOE, USA, Army Res Off ID PARTIAL-DIFFERENTIAL EQUATIONS C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Greenstadt, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 1439-7358 BN 3-540-66787-3 J9 LECT NOTES COMP SCI PY 2000 VL 11 BP 337 EP 342 PG 6 WC Engineering, Multidisciplinary; Mathematics, Applied; Mechanics; Physics, Mathematical SC Engineering; Mathematics; Mechanics; Physics GA BR11S UT WOS:000165694700030 ER PT B AU Gorkavyi, NN Ozernoy, LM Mather, JC Heap, S AF Gorkavyi, NN Ozernoy, LM Mather, JC Heap, S BE Garzon, F Eiroa, C DeWinter, D Mahoney, TJ TI Orbital motion of resonant clumps in dusty circumstellar disks as a signature of an embedded planet SO DISKS, PLANETESIMALS, AND PLANETS, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Euroconference on Disks, Planetesimals, and Planets CY JAN 24-28, 2000 CL PUERTO LA CRUZ, SPAIN SP European Community, Spain Minist Sci & Educ, Autonomous Univ Madrid, Spanish Natl Res Council, Spanish Astron Soc, Banco Bilbao Vizcaya, Inst Astrofis Canarias, DISA AB We have applied a powerful numerical approach to compute, with a high resolution, the structure of dusty circumstellar disks with embedded planets. We emphasize some testable implications of our simulations which would verify the presence of a planet via thermal emission of one or more dusty clumps which are in mean motion resonances with the planet. In particular, our simulations indicate that Vega may have a massive planet of m similar to 2 M(Jup) (M(Jup) being Jupiter's mass) at a distance of 50-60 AU, and Epsilon Eri may have a less massive planet of m similar to 0 2 M(Jup) at a similar distance of 55-65 AU. This conclusion is testable: each resonant feature is stationary in the reference frame corotating with the planet, but it is not so for the observer at Earth. Therefore, if our interpretation of asymmetric clumps in circumstellar disks as dynamical resonant structures is correct, the above pattern revolves around the star with an angular velocity of (1.2-1.6)degrees /yr (Vega) and (0.6-0.8)degrees /yr (epsilon Eri)-a prediction that can be tested on a timescale of several years. C1 NASA, Goddard Space Flight Ctr, NAS, NRC, Greenbelt, MD 20771 USA. RP Gorkavyi, NN (reprint author), NASA, Goddard Space Flight Ctr, NAS, NRC, Code 685, Greenbelt, MD 20771 USA. RI heap, sara/E-2237-2012 NR 6 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 1-58381-051-X J9 ASTR SOC P PY 2000 VL 219 BP 51 EP 55 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR94A UT WOS:000168122500007 ER PT B AU Turmon, M Granat, R Katz, DS AF Turmon, M Granat, R Katz, DS GP IEEE IEEE IEEE TI Software-implemented fault detection for high-performance space applications SO DSN 2000: INTERNATIONAL CONFERENCE ON DEPENDABLE SYSTEMS AND NETWORKS, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Dependable Systems and Networks CY JUN 25-28, 2000 CL NEW YORK, NY SP IEEE Comp Soc, Tech Comm Fault Tolerant Comp, IFIP Working Grp 10 4 Dependable Comp & Fault Tolerance, AT&T, Lucent Technologies, Compaq Comp Corp, Georgia Inst Technol, IBM Corp, LAAS CNRS, Microsoft Corp ID TOLERANCE AB We describe and test a software approach to overcoming radiation-induced errors in spaceborne applications running on commercial off-the-shelf components. The approach uses checksum methods to validate results returned by a numerical subroutine operating subject to unpredictable errors in data. We can treat subroutines that return results satisfying a necessary condition having a linear form; the checksum tests compliance with this condition. We discuss the theory and practice of setting numerical tolerances to separate errors caused by a fault from those inherent infinite-precision numerical calculations. We test both the general effectiveness of the linear fault tolerant schemes we propose, and the correct behavior of our parallel implementation of them. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Turmon, M (reprint author), CALTECH, Jet Prop Lab, MS 126-347, Pasadena, CA 91109 USA. OI Katz, Daniel S./0000-0001-5934-7525 NR 14 TC 4 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0707-7 PY 2000 BP 107 EP 116 DI 10.1109/ICDSN.2000.857522 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BQ74U UT WOS:000089400400012 ER PT B AU Chen, FN Craymer, L Deifik, J Fogel, AJ Katz, DS Silliman, AG Some, RR Upchurch, SA Whisnant, K AF Chen, FN Craymer, L Deifik, J Fogel, AJ Katz, DS Silliman, AG Some, RR Upchurch, SA Whisnant, K GP IEEE IEEE IEEE TI Demonstration of the remote exploration and experimentation (REE) fault-tolerant parallel-processing supercomputer for spacecraft onboard scientific data processing SO DSN 2000: INTERNATIONAL CONFERENCE ON DEPENDABLE SYSTEMS AND NETWORKS, PROCEEDINGS LA English DT Proceedings Paper CT International Conference on Dependable Systems and Networks CY JUN 25-28, 2000 CL NEW YORK, NY SP IEEE Comp Soc, Tech Comm Fault Tolerant Comp, IFIP Working Grp 10 4 Dependable Comp & Fault Tolerance, AT&T, Lucent Technologies, Compaq Comp Corp, Georgia Inst Technol, IBM Corp, LAAS CNRS, Microsoft Corp AB This paper is the written explanation for a demonstration of the REE Project's work to-date. The demonstration is intended to simulate an REE system that might exist on a Mars Rover, consisting of multiple COTS processors, a COTS network, a COTS node-level operating system, REE middleware, and an REE application. The specific application performs texture processing of images. It was chosen as a building block of automated geological processing that will eventually be used for both navigation and data processing. Because the COTS hardware is nor radiation hardened, SEU-induced soft errors will occur. These errors are simulated in the demonstration by use of a software-implemented fault-injector and are injected at a rate much higher than is realistic for the sake of viewer interest. Both the application and the middleware contain mechanisms far both detection of and recovery from these faults, and these mechanisms are tested by this very high fault-rate. The consequence of the REE system being able to tolerate this fault rate while continuing to process data is that the system will easily be able to handle the true fault rate. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chen, FN (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0707-7 PY 2000 BP 367 EP 372 DI 10.1109/ICDSN.2000.857562 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BQ74U UT WOS:000089400400039 ER PT J AU Korotaev, GK Saenko, OA Koblinsky, CJ Demyshev, SG Knysh, VV AF Korotaev, GK Saenko, OA Koblinsky, CJ Demyshev, SG Knysh, VV TI Determination of the accuracy of the method and results from assimilation of TOPEX/POSEIDON altimetric data into a model of the overall circulation in the Black Sea SO EARTH OBSERVATION AND REMOTE SENSING LA English DT Article AB The recovery of the dynamic level of the Black Sea from TOPEX/POSEIDON satellite altimetric measurements is considered; the information is subsequently assimilated into a numerical model. The accuracy of recovery of the dynamic level is estimated by comparing it with the sea level calculated from ComSBlack'93 hydrological survey data. It is shown that there is a good correspondence between the mean-square deviations and the spectra of fluctuations of the level on spatial scales of from 50 km and on timescales of from one month. The method and preliminary results from the assimilation of TOPEX/POSEIDON data into a numerical model of the Black Sea are considered. C1 Ukrainian Acad Sci, Inst Marine Hydrophys, Sevastopol, Ukraine. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Nucl Energy & Ind, Sevastopol, Ukraine. RP Korotaev, GK (reprint author), Ukrainian Acad Sci, Inst Marine Hydrophys, Sevastopol, Ukraine. NR 7 TC 2 Z9 2 U1 0 U2 1 PU HARWOOD ACAD PUBL GMBH PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1024-5251 J9 EARTH OBS REMOT SEN+ JI Earth Observ. Remote Sens. PY 2000 VL 16 IS 3 BP 359 EP 378 PG 20 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 349AF UT WOS:000089021100001 ER PT S AU Lee, RB Priestley, KJ Barkstrom, BR Thomas, S Al-Hajjah, A Paden, J Pandey, DK Wilson, RS Smith, GL AF Lee, RB Priestley, KJ Barkstrom, BR Thomas, S Al-Hajjah, A Paden, J Pandey, DK Wilson, RS Smith, GL BE Barnes, WL TI Terra Spacecraft CERES flight model 1 and 2 sensor measurement precisions: ground to flight determinations SO EARTH OBSERVING SYSTEMS V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Earth Observing Systems V CY AUG 02-04, 2000 CL SAN DIEGO, CA SP SPIE, Remote Sensing Soc DE vacuum radiometry; thermistor bolometer; tungsten lamp; blackbody; CERES; Terra; TRMM; longwave; shortwave; silicon photodiode ID ENERGY SYSTEM CERES; CLOUDS; CALIBRATIONS AB On December 18, 1999, the Clouds and the Earth's Radiant Energy System (CERES) flight models 1 (FM1) and 2 (FM2) sets of scanning thermistor bolometer sensors were launched into orbit aboard the NASA Terra Spacecraft. The sensors measure earth radiances in the broadband shortwave solar (0.3 mum - 5.0 mum) and total(0.3 mum - >100 mum) spectral bands, as well as in the 8 -12 micrometer water vapor window, narrow-band spectral band. In order to measure sensor response drifts or shifts, inflight blackbody and evacuated tungsten lamp calibration systems were built into the CERES instrumentation. These systems were used to determine the sensor responses during the ground/pre-launch, ground to orbit, and on-orbit phases of the sensor calibrations. Analyses of the pre-launch, vacuum ground calibrations indicated that the CERES sensor responses can change as much as 0.6% between vacuum and ground ambient atmospheric pressure environments. The sensor responses were found to vary directly with the temperature as much as 2% between the 311 K and 270 K thermal environment of the vacuum calibration facility. From the vacuum ground calibration through the on-orbit calibration phases, the Terra Spacecraft CERES broadband total and shortwave sensor responses and in-flight calibration sources maintained their radiance measurement ties to an International Temperature Scale of 1990 (ITS-90) radiometric scale at precision levels approaching +/- 0.3% (0.3 Wm(-2)sr(-1)). Analyses of the ground and on-orbit calibrations are presented and discussed using built-in, reference blackbody and lamp observations. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lee, RB (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3780-8 J9 P SOC PHOTO-OPT INS PY 2000 VL 4135 BP 1 EP 12 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing; Optics SC Engineering; Instruments & Instrumentation; Remote Sensing; Optics GA BR62E UT WOS:000166963900001 ER PT S AU Smith, GL Pandey, DK Spence, PL Priestley, KJ Barkstrom, BR Lee, RB Paden, J Thomas, S Wilson, RS Al-Hajjah, A AF Smith, GL Pandey, DK Spence, PL Priestley, KJ Barkstrom, BR Lee, RB Paden, J Thomas, S Wilson, RS Al-Hajjah, A BE Barnes, WL TI Determination and validation of slow mode coefficients of the Clouds and the Earth's Radiant Energy System (CERES) scanning thermistor bolometers SO EARTH OBSERVING SYSTEMS V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Earth Observing Systems V CY AUG 02-04, 2000 CL SAN DIEGO, CA SP SPIE, Remote Sensing Soc DE CERES; TRMM; Terra; thermistor bolometer; time response; blackbody; tungsten lamp; calibration ID SENSORS AB The Clouds and the Earth's Radiant Energy System (CERES) scanning thermistor bolometers have a response time of approximately 9 ms for 98 to 99% of the signal, after which there is a slow change for the remaining 1 to 2% of the response due to a slow mode. This paper describes the theoretical and experimental procedures used in producing the slow mode coefficients for the CERES Flight Models 1 and 2 instruments aboard the Terra spacecraft, which was launched on December 18, 1999. The response behavior for the total thermistor bolometer (0.3 - > 100 mum) acid window channel (8-12 mum) were determined by analyzing the internal blackbody calibration ground data while the shortwave thermistor bolometer (0.3 - 5 mum) was determined using shortwave internal calibration source ground data obtained at the TRW calibration facility at Redondo Beach, California. These slow mode coefficients agree with the coefficients obtained by analyzing the in-flight calibration data. A numerical filter removes the effects of the slow mode from the measurements. The method may be applicable to other instruments which have spurious transients. C1 Virginia Polytech Inst & State Univ, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, GL (reprint author), Virginia Polytech Inst & State Univ, NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3780-8 J9 P SOC PHOTO-OPT INS PY 2000 VL 4135 BP 25 EP 38 DI 10.1117/12.494226 PG 14 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing; Optics SC Engineering; Instruments & Instrumentation; Remote Sensing; Optics GA BR62E UT WOS:000166963900003 ER PT S AU Montgomery, H Che, NZ Bowser, J AF Montgomery, H Che, NZ Bowser, J BE Barnes, WL TI Tracking MODIS gain change on-orbit by relating it to SRCA lamp parameters SO EARTH OBSERVING SYSTEMS V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Earth Observing Systems V CY AUG 02-04, 2000 CL SAN DIEGO, CA SP SPIE, Remote Sensing Soc AB This paper addresses the methodology and algorithm for using the Spectro-Radiometric Calibration Assembly (SRCA) lamp electrical parameters to track its output band radiance change. This allows the use of the SRCA to track MODurate resolution Imaging Spectroradiometer (MODIS) detector gain variation at different orbit positions because the MODIS dn change is attributed to its gain change after subtracting the SRCA output radiance change itself. Pre-launch test data show that using lamp current as a parameter is valid. Orbit data prove that the approach is valid for longer periods of time for all Solar Reflective Bands (SRBs). Data indicate that the MODIS has undetectable gain change at different orbit positions. C1 Goddard Space Flight Ctr, Greenbelt, MD 20721 USA. RP Montgomery, H (reprint author), Goddard Space Flight Ctr, Greenbelt, MD 20721 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3780-8 J9 P SOC PHOTO-OPT INS PY 2000 VL 4135 BP 80 EP 87 DI 10.1117/12.494247 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing; Optics SC Engineering; Instruments & Instrumentation; Remote Sensing; Optics GA BR62E UT WOS:000166963900008 ER PT J AU Heki, K Kato, T Rizos, C Xu, PL Hirahara, K Ivins, ER Saito, A Tsuda, T AF Heki, K Kato, T Rizos, C Xu, PL Hirahara, K Ivins, ER Saito, A Tsuda, T TI Application of GPS and other space geodetic techniques to Earth Sciences (1) - Preface SO EARTH PLANETS AND SPACE LA English DT Editorial Material C1 Natl Astron Observ, Div Earth Rotat, Mizusawa, Japan. Univ Tokyo, Earthquake Res Inst, Tokyo 113, Japan. Univ New S Wales, Sch Geomat Engn, Sydney, NSW, Australia. Kyoto Univ, Disaster Prevent Res Inst, Uji, Japan. Nagoya Univ, Grad Sch Sci, Nagoya, Aichi, Japan. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Kyoto Univ, Dept Geophys, Kyoto, Japan. Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Uji, Japan. RP Heki, K (reprint author), Natl Astron Observ, Div Earth Rotat, Mizusawa, Japan. NR 0 TC 0 Z9 0 U1 0 U2 0 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2000 VL 52 IS 10 BP 655 EP 655 PG 1 WC Geosciences, Multidisciplinary SC Geology GA 376DN UT WOS:000165443100001 ER PT J AU Kursinski, ER Healy, SB Romans, LJ AF Kursinski, ER Healy, SB Romans, LJ TI Initial results of combining GPS occultations with ECMWF global analyses within a 1DVar framework SO EARTH PLANETS AND SPACE LA English DT Article ID RADIO OCCULTATION; POSITIONING SYSTEM; EARTHS ATMOSPHERE AB We present results of combining occultation refractivity profiles from GPS/MET with ECMWF global analyses in a 1DVar framework in order to separate the wet and dry contributions to refractivity and assess their impact on the analyzed temperature, surface pressure and specific humidity fields. We find significant zonal mean temperature, surface pressure and humidity differences between the 1DVar solutions and the ECMWF analyses reflecting biases between the GPS refractivities and ECMWF analyses. Large profile-to-profile temperature discrepancies in the tropical lower stratosphere are due to waves not represented in the analyses. The 1DVar solution is generally drier than ECMWF particularly in the southern subtropics. Lack of moisture above 300 hPa in the present model caused the solution to make large adjustments in low latitude surface pressure and tropospheric temperatures to increase upper troposphere densities and compensate for the missing upper level moisture. The discrepancies between the solution and the background and observational data sets represent roughly a 2-sigma level of agreement rather than the 1-sigma level desired in a 1DVar solution. Given the simplicity of our error covariances, our results are promising as a first step. In the future, the error covariances need to be refined and, in particular, to vary with location. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Met Off, Numer Weather Predict Div, Bracknell RG12 2SZ, Berks, England. RP Kursinski, ER (reprint author), Univ Arizona, Dept Atmospher Sci, POB 210081, Tucson, AZ 85721 USA. NR 14 TC 23 Z9 26 U1 0 U2 1 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2000 VL 52 IS 11 BP 885 EP 892 PG 8 WC Geosciences, Multidisciplinary SC Geology GA 385LB UT WOS:000166004800001 ER PT J AU Ivins, ER Raymond, CA James, TS AF Ivins, ER Raymond, CA James, TS TI The influence of 5000 year-old and younger glacial mass variability on present-day crustal rebound in the Antarctic Peninsula SO EARTH PLANETS AND SPACE LA English DT Article ID ICE-SHEET; MAXIMUM; EVOLUTION; HISTORY; BREAKUP; BALANCE; MARGIN; RECORD; SHELF; LAND AB Assessment of Antarctic rebound is complicated by two issues: (1) The total ice volume at Last Glacial Maximum is contentious, with estimates ranging from just a few meters to several tens of meters of equivalent eustatic sea level rise. (2) The late-Holocene mass budget is also uncertain. Space-based geodesy may provide important data in the coming years for estimating the recent ice mass balance state of Antarctica. Toward this end, GPS has an important role for isolating the solid earth movements that are associated with postglacial rebound. Here we provide numerical examples of vertical motions that are predicted by coupling realistic glacial load histories to 20th century ice mass imbalance estimates for the Antarctic Peninsula. The main complexity revealed by these examples is the striking difference among predictions that have an oscillatory mass change during the last 5000 to 50 years, as opposed to those having a continuous (non-oscillatory) mass drawdown of the grounded ice sheet. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Geol Survey Canada, Sidney, BC, Canada. RP Ivins, ER (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI James, Thomas/D-9301-2013 OI James, Thomas/0000-0001-7321-047X NR 31 TC 25 Z9 25 U1 0 U2 2 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158, JAPAN SN 1343-8832 J9 EARTH PLANETS SPACE JI Earth Planets Space PY 2000 VL 52 IS 11 BP 1023 EP 1029 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 385LB UT WOS:000166004800025 ER PT S AU Jonsson, AK Frank, JD AF Jonsson, AK Frank, JD BE Horn, W TI A framework for dynamic constraint reasoning using procedural constraints SO ECAI 2000: 14TH EUROPEAN CONFERENCE ON ARTIFICIAL INTELLIGENCE, PROCEEDINGS SE Frontiers in Artificial Intelligence and Applications LA English DT Proceedings Paper CT 14th European Conference on Artificial Intelligence CY AUG 20-25, 2000 CL BERLIN, GERMANY SP European Coordinating Comm Artificial Intelligence, German Informat Soc, Humboldt Univ ID NETWORKS AB Many complex real-world decision problems, such as planning, contain an underlying constraint reasoning problem. The feasibility of a solution candidate then depends on the consistency of the associated constraint problem instance. The underlying constraint problems are invariably dynamic, as higher level decisions result in variables, values, and constraints being added and removed. Tn real-world reasoning applications, constraints may be arbitrarily complex, variables may have continuous domains, and neither variables nor values may be effectively enumerable beforehand. Such applications, therefore, present a number of significant challenges for a dynamic constraint reasoning mechanism. In this paper, we introduce a general framework for representing and reasoning about dynamic constraint networks arising from complex real-world applications. It is based on the use of procedures to represent and effectively reason about general constraints. The framework can handle arbitrary changes to the network, including the addition and deletion of variables and values. It can reason with real-valued variables, and utilize special-purpose reasoning methods, such as arithmetic problem solving, in the form of procedures. The resulting framework is based on a sound theoretical foundation, which guarantees termination and correctness. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Mailstop 269-2, Moffett Field, CA 94035 USA. EM jonsson@ptolemy.arc.nasa.gov; frank@ptolemy.arc.nasa.gov NR 12 TC 5 Z9 5 U1 0 U2 0 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0922-6389 BN 1-58603-013-2 J9 FRONT ARTIF INTEL AP PY 2000 VL 54 BP 93 EP 97 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BR29N UT WOS:000166049100018 ER PT S AU Rajan, K Bernard, D Dorais, G Gamble, E Kanefsky, B Kurien, J Millar, W Muscettola, N Nayak, P Rouquette, N Smith, B Taylor, W Tung, YW AF Rajan, K Bernard, D Dorais, G Gamble, E Kanefsky, B Kurien, J Millar, W Muscettola, N Nayak, P Rouquette, N Smith, B Taylor, W Tung, YW BE Horn, W TI Remote agent: An autonomous control system for the new millennium SO ECAI 2000: 14TH EUROPEAN CONFERENCE ON ARTIFICIAL INTELLIGENCE, PROCEEDINGS SE FRONTIERS IN ARTIFICIAL INTELLIGENCE AND APPLICATIONS LA English DT Proceedings Paper CT 14th European Conference on Artificial Intelligence CY AUG 20-25, 2000 CL BERLIN, GERMANY SP European Coordinating Comm Artificial Intelligence, German Informat Soc, Humboldt Univ DE closed loop control; constraint-based planning; scheduling; temporal networks; spacecraft autonomy AB On May 17th 1999, the Remote Agent (RA) became the first Artificial Intelligence based closed loop autonomous control system to take control of a spacecraft. The RA commanded NASA's New Millennium Deep Space One spacecraft when it was 65 million miles away from earth. For a period of one week this system commanded DSl's Ion Propulsion System, its camera, its attitude control and navigation systems. A primary goal of this experiment was to provide an on-board demonstration of spacecraft autonomy. This demonstration included both nominal operations with goal-oriented commanding and closed-loop plan execution, and fault protection capabilities with failure diagnosis and recovery, on-board replanning following unrecoverable failures, and system-level fault protection. This paper describes the Remote Agent Experiment and the model based approaches to Planning and Scheduling, Plan Execution and Fault Diagnosis and Recovery technologies developed at NASA Ames Research Center and the Jet Propulsion Laboratory. C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Rajan, K (reprint author), NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU I O S PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0922-6389 BN 1-58603-013-2 J9 FR ART INT PY 2000 VL 54 BP 726 EP 730 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BR29N UT WOS:000166049100138 ER PT S AU Bar-Cohen, Y Leary, S Yavrouian, A Oguro, K Tadokoro, S Harrison, J Smith, J Su, J AF Bar-Cohen, Y Leary, S Yavrouian, A Oguro, K Tadokoro, S Harrison, J Smith, J Su, J BE Zhang, QM Furukawa, T BarCohen, Y Scheinbeim, Y TI Challenges to the transition to the practical application of IPMC as artificial-muscle actuators SO ELECTROACTIVE POLYMERS (EAP) SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Electroactive Polymers at the 1999 MRS Fall Meeting CY NOV 29-DEC 01, 1999 CL BOSTON, MA SP USN, Off Res, Daikin US Corp, Kureha Chem Ind Co Ltd, Toray Techno Co Ltd, Mat Res Soc AB In recent years, electroactive polymers (EAP) materials have gained recognition as potential actuators with unique capabilities having the closest performance resemblance to biological muscles. ion-exchange membrane metallic composites (IPMC) are one of the EAP materials with such a potential. The strong bending that is induced by IPMC offers attractive actuation for the construction of various mechanisms. Examples of applications that were conceived and investigated for planetary tasks include a gripper and wiper. The development of the wiper for dust removal from the window of a miniature rover, planned for launch to an asteroid, is the subject of this reported study. The application of EAP in space conditions is posing great challenge due to the harsh operating conditions that are involved and the critical need for robustness and durability. The various issues that can affect the application of IPMC were examined including operation in vacuum, low temperatures, and the effect of the electromechanical and ionic characteristics of IPMC on its actuation capability. The authors introduced highly efficient IPMC materials, mechanical modeling, unique elements and protective coatings in an effort to enhance the applicability of IPMC as an actuator of a planetary dust-wiper. Results showed that the IPMC technology is not ready yet for practical implementation due to residual deformation that is introduced under DC activation and the difficulty to protect the material ionic content over the needed 3-years durability. Further studies are under way to overcome these obstacles and other EAP materials are also being considered as alternative bending actuators. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MC 82-105, Pasadena, CA 91109 USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-508-0 J9 MATER RES SOC SYMP P PY 2000 VL 600 BP 13 EP 20 PG 8 WC Physics, Applied; Polymer Science SC Physics; Polymer Science GA BQ75U UT WOS:000089404300002 ER PT S AU Su, J Ounaies, Z Harrison, JS AF Su, J Ounaies, Z Harrison, JS BE Zhang, QM Furukawa, T BarCohen, Y Scheinbeim, Y TI Ferroelectric and piezoelectric properties of blends of poly(vinylidene fluoride-trifluoroethylene) and a graft elastomer SO ELECTROACTIVE POLYMERS (EAP) SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Electroactive Polymers at the 1999 MRS Fall Meeting CY NOV 29-DEC 01, 1999 CL BOSTON, MA SP USN, Off Res, Daikin US Corp, Kureha Chem Ind Co Ltd, Toray Techno Co Ltd, Mat Res Soc ID VINYLIDENE FLUORIDE; POLARIZATION; COPOLYMER; POLYMERS; FIELD AB A piezoelectric polymeric blend system has been developed. The system contains two components: ferroelectric poly(vinylidene fluoride-trifluoroethylene) and graft elastomer. The remanent polarization, P-r, and the piezoelectric strain coefficient, d(31), of the blends have been studied as a function of relative composition of the two components, temperature and frequency. Both blended copolymer and graft unit in the elastomer contribute to the total crystallinity of the blend-system, and hence to the remanent polarization and piezoelectricity. The piezoelectric strain coefficient, d(31), of the blend systems shows dependence on both the remanent polarization and the mechanical stiffness, which in turn are determined by the fraction of the two components in the blends. This mechanism makes it possible for the piezoelectric strain response of the blend to be tailored by adjusting the relative composition. Although P-r of the copolymer is higher than that of the blends, the blend films containing 75 wt.% copolymer exhibit a higher d(31) at room temperature, possibly due to their lower modulus. The blend films containing 50 wt.% copolymer exhibit a constant value of d(31), from room temperature to 70 degrees C. C1 NASA, Natl Res Council, LaRC, Hampton, VA 23681 USA. RP Su, J (reprint author), NASA, Natl Res Council, LaRC, Hampton, VA 23681 USA. NR 8 TC 4 Z9 5 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-508-0 J9 MATER RES SOC SYMP P PY 2000 VL 600 BP 95 EP 100 PG 6 WC Physics, Applied; Polymer Science SC Physics; Polymer Science GA BQ75U UT WOS:000089404300012 ER PT S AU Su, J Harrison, JS St Clair, TL Bar-Cohen, Y Leary, S AF Su, J Harrison, JS St Clair, TL Bar-Cohen, Y Leary, S BE Zhang, QM Furukawa, T BarCohen, Y Scheinbeim, Y TI Electrostrictive graft elastomers and applications SO ELECTROACTIVE POLYMERS (EAP) SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Electroactive Polymers at the 1999 MRS Fall Meeting CY NOV 29-DEC 01, 1999 CL BOSTON, MA SP USN, Off Res, Daikin US Corp, Kureha Chem Ind Co Ltd, Toray Techno Co Ltd, Mat Res Soc ID POLYURETHANE ELASTOMER; POLYMER DIELECTRICS; ACTUATION AB Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. In this work, we present a new class of electromechanically active polymers that can potentially be used as actuators to meet many NASA needs. The materials are graft elastomers that offer high strain under an applied electric field. Due to its higher mechanical modulus, this elastomer also has a higher strain energy density as compared to previously reported electrostrictive polyurethane elastomers. The dielectric, mechanical and electromechanical properties of this new electrostrictive elastomer have been studied as a function of temperature and frequency.. Combined with structural analysis using x-ray diffraction and differential scanning calorimetry on the new elastomer, structure-property interrelationship and mechanisms of the electric field induced strain in the graft elastomer have also been investigated. This electroactive polymer (EAP) has demonstrated high actuation strain and high mechanical energy density. The combination of these properties with its tailorable molecular composition and excellent processability makes it attractive for a variety of actuation tasks. The experimental results and applications will be presented. C1 NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. RP Su, J (reprint author), NASA, Langley Res Ctr, Natl Res Council, Hampton, VA 23681 USA. NR 7 TC 6 Z9 8 U1 2 U2 7 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-508-0 J9 MATER RES SOC SYMP P PY 2000 VL 600 BP 131 EP 136 PG 6 WC Physics, Applied; Polymer Science SC Physics; Polymer Science GA BQ75U UT WOS:000089404300016 ER PT S AU Park, C Ounaies, Z Su, J Smith, JG Harrison, JS AF Park, C Ounaies, Z Su, J Smith, JG Harrison, JS BE Zhang, QM Furukawa, T BarCohen, Y Scheinbeim, Y TI Polarization stability of amorphous piezoelectric polymides SO ELECTROACTIVE POLYMERS (EAP) SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Electroactive Polymers at the 1999 MRS Fall Meeting CY NOV 29-DEC 01, 1999 CL BOSTON, MA SP USN, Off Res, Daikin US Corp, Kureha Chem Ind Co Ltd, Toray Techno Co Ltd, Mat Res Soc ID POLYIMIDES AB Amorphous polyimides containing polar functional groups have been synthesized and investigated for potential use as high temperature piezoelectric sensors. The thermal stability of the piezoelectric effect of one polyimide was evaluated as a function of various curing and poling conditions under dynamic and static thermal stimuli. First, the polymer samples were thermally cycled under strain by systematically increasing the maximum temperature from 50 degrees C to 200 degrees C while the piezoelectric strain coefficient was being measured. Second, the samples were isothermally aged at an elevated temperature in air, and the isothermal decay of the remanent polarization was measured at room temperature as a function of time. Both conventional and corona poling methods were evaluated. This material exhibited good thermal stability of the piezoelectric properties up to 100 degrees C. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Park, C (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-508-0 J9 MATER RES SOC SYMP P PY 2000 VL 600 BP 153 EP 158 PG 6 WC Physics, Applied; Polymer Science SC Physics; Polymer Science GA BQ75U UT WOS:000089404300019 ER PT J AU Ratnakumar, BV Smart, MC Huang, CK Perrone, D Surampudi, S Greenbaum, SG AF Ratnakumar, BV Smart, MC Huang, CK Perrone, D Surampudi, S Greenbaum, SG TI Lithium ion batteries for Mars exploration missions SO ELECTROCHIMICA ACTA LA English DT Article; Proceedings Paper CT 6th International Symposium on Polymer Electrolytes (ISPE-6) CY NOV 01-06, 1998 CL HAYAMA, JAPAN SP Novartis Fdn Promot Sci, Ogasarara Fdn Promot Sci, Pionics Corp, Terumo Fdn Promot Sci, USAF Off Sci Res, Yuasa Corp DE spacecraft batteries; surface landers; Mars; lithium ion ID POLYMER ELECTROLYTES AB The desired performance characteristics and physical requirements of spacecraft batteries for planetary exploration are reviewed, particularly with respect to surface landers and revers intended for near-future Mars missions. The use of lithium ion batteries is justified in terms of significant savings on mass and volume, and more importantly of superior low temperature performance deemed essential in the Mars lander and rover missions. Use of these batteries in planetary orbiters may require further improvements in their cycle life, especially at low depths of discharge. Various strategies currently being adopted to prolong the cycle life for orbiter applications, as well as, for extending their operating range down to temperatures as low as -30 degrees C for more imminent Mars lander and rover missions are briefly discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Greenbaum, SG (reprint author), CUNY Hunter Coll, Dept Phys, 695 Pk Ave, New York, NY 10021 USA. NR 14 TC 18 Z9 23 U1 1 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-4686 J9 ELECTROCHIM ACTA JI Electrochim. Acta PY 2000 VL 45 IS 8-9 BP 1513 EP 1517 DI 10.1016/S0013-4686(99)00367-9 PG 5 WC Electrochemistry SC Electrochemistry GA 274TB UT WOS:000084780200053 ER PT S AU Delgado, F Altman, S Abernathy, MF White, J AF Delgado, F Altman, S Abernathy, MF White, J BE Verly, JG TI Virtual cockpit window for the X-38 crew return vehicle SO ENHANCED AND SYNTHETIC VISION 2000 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Enhanced and Synthetic Vision 2000 CY APR 24-25, 2000 CL ORLANDO, FL SP SPIE DE synthetic vision; simulation; flight visualization; flight guidance; human factors; and situation awareness AB Synthetic Vision has the potential to significantly improve the situation awareness for aircraft that do not possess windshields or windows. Windshields and windows add considerable weight, and risk to vehicle design. NASA's X-38 crew-return vehicle has a windowless cockpit design. Synthetic vision tools have been developed to provide a simulated real-time 3-D perspective to X-38 crews. This virtual cockpit window provides an all-weather, day/night situation awareness display, enriched with a wide variety of flight-related information. Already successfully demonstrated in several flight tests, this paper will discuss the challenges faced developing this system and the results of initial flight tests. While many different types of digital topography, maps, and imagery are available, seamlessly integrating the data requires new approaches not available in standard geographic information systems or flight simulation software. Since much of the data is in cylindrical geographic coordinates, and the computer display API works in Cartesian coordinates, selection of an efficient and accurate coordinate system conversion is crucial. We will describe a new method of utilizing a multi-resolution digital topography database that provides high-resolution near-field performance (up to 1 meter) with a complete horizon model, yet retains excellent display speed. The LandForm FlightVision system employed for this purpose utilizes five different resolutions of digital topography, in order to model a flight from space to earth landing. Real-time situational awareness provided by the virtual cockpit window has been enhanced by the display of a dynamic landing rage model. This model incorporates vehicle flight characteristics and winds aloft information. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Delgado, F (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3649-6 J9 P SOC PHOTO-OPT INS PY 2000 VL 4023 BP 63 EP 70 DI 10.1117/12.389361 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BQ62H UT WOS:000088995100007 ER PT J AU Wood, J Hysong, SJ Lugg, DJ Harm, DL AF Wood, J Hysong, SJ Lugg, DJ Harm, DL TI Is it really so bad? A comparison of positive and negative experiences in Antarctic winter stations SO ENVIRONMENT AND BEHAVIOR LA English DT Article AB This study examined the range of positive and negative themes reported by 104 Australian Antarctic winter personnel at four stations during two austral winters. Reports from the expeditioners were subjected to a content analysis using the TextSmart software from SPSS, inc. Results indicated that, although the list of negative experiences is lengthy. most events are relatively rare. On the other hand, although the list of positive experiences is short, the frequencies with which they are reported are much greater than for most of the problems. Possible explanations for these themes and for future directions are discussed. C1 Rice Univ, Houston, TX 77251 USA. Lyndon B Johnson Space Ctr, Neurosci Labs, Houston, TX USA. RP Wood, J (reprint author), Krug Life Sci Inc, Psychol & Behav Lab, 1290 Hercules,Suite 120, Houston, TX 77058 USA. RI Hysong, Sylvia/B-8420-2008 OI Hysong, Sylvia/0000-0002-9063-5207 NR 23 TC 20 Z9 24 U1 0 U2 0 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0013-9165 J9 ENVIRON BEHAV JI Environ. Behav. PD JAN PY 2000 VL 32 IS 1 BP 84 EP 110 DI 10.1177/00139160021972441 PG 27 WC Environmental Studies; Psychology, Multidisciplinary SC Environmental Sciences & Ecology; Psychology GA 271RG UT WOS:000084606800006 PM 11542948 ER PT S AU Bloomberg, JJ Mulavara, AP Hillman, EJ McDonald, PV Cohen, HS AF Bloomberg, JJ Mulavara, AP Hillman, EJ McDonald, PV Cohen, HS BE Claussen, CF Haid, CT Hofferberth, B TI Dynamic visual acuity: A test of sensorimotor integration in astronauts and patients SO EQUILIBRIUM RESEARCH, CLINICAL EQUILIBRIOMETRY AND MODERN TREATMENT SE INTERNATIONAL CONGRESS SERIES LA English DT Meeting Abstract CT 20th Regular Meeting of the Barany-Society CY SEP 12-15, 1998 CL WURZBURG, GERMANY SP Barany Soc C1 NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 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 0531-5131 BN 0-444-50012-X J9 INT CONGR SER PY 2000 VL 1201 BP 135 EP 135 PG 1 WC Neurosciences; Otorhinolaryngology SC Neurosciences & Neurology; Otorhinolaryngology GA BQ40Q UT WOS:000088270100041 ER PT S AU Yuan, J Vandooren, A Swift, G Patel, JU Kayali, S AF Yuan, J Vandooren, A Swift, G Patel, JU Kayali, S BE Schurmann, B TI Evaluation of the sensitivity of newly emerging FD-SOI technology to the low temperature and radiation environment in space SO ESCCON 2000: EUROPEAN SPACE COMPONENTS CONFERENCE, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT European Space Components Conference (ESCCON 2000) CY MAR 21-23, 2000 CL NOORDWIJK, NETHERLANDS AB The performance of 0.25, 0.3 and 0.35 mu m fully-depleted SOI transistors is characterized at low temperatures (between 77 and 300K) and after proton irradiation, Device parameters such as drain current, mobility, threshold voltage, subthreshold slope, and Early voltage are analyzed. The suitability of sub-micron FD-SOT devices is examined for harsh environments as encountered in deep space exploration missions. The results indicate significant performance improvements in mobility, subthreshold slope, and drain current with decreasing temperature down to 100K. The increase in threshold voltage dominates below this temperature, leading to a decrease in saturation current between 100 and 77K, Radiation experiments show the transistors did not survive above 150Krads(Si), most likely due to the single-event gate rupture effect. Mobility and subthreshold slope are observed to degrade with total dose, Threshold voltage improves up to 75Krads(Si) and degrades beyond this level. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yuan, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 303-230, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-756-9 J9 ESA SP PUBL PY 2000 VL 439 BP 375 EP 380 PG 6 WC Engineering, Aerospace SC Engineering GA BQ80A UT WOS:000089547400057 ER PT S AU Keyes, DE AF Keyes, DE BE Bode, A Ludwig, T Karl, W Wismuller, R TI Four horizons for enhancing the performance of parallel simulations based on partial differential equations SO EURO-PAR 2000 PARALLEL PROCESSING, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 6th International Euro-Par 2000 Conference CY AUG 29-SEP 01, 2000 CL MUNICH, GERMANY SP Tech Univ Munchen, Deutsch Forsch Gemeinsch, KON WIHR, ACM IFIP, IEEE Task Force Cluster Comp, Force Comp GmbH, Fujitsu Siemens Com Technol, Landesaupstadt Munchen, Lufthansa, Deutsch Bahn AG AB Simulations of PDE-based systems, such as flight vehicles, the global climate, petroleum reservoirs, semiconductor devices, and nuclear weapons, typically perform an order of magnitude or more below other scientific simulations (e.g., from chemistry and physics) with dense linear algebra or N-body kernels at their core. In this presentation, we briefly review the algorithmic structure of typical PDE solvers that is responsible for this situation and consider possible architectural and algorithmic sources for performance improvement. Some of these improvements are also applicable to other types of simulations, but we examine their consequences for PDEs: potential to exploit orders of magnitude more processor-memory units, better organization of the simulation for today's and likely near-future hierarchical memories, alternative formulations of the discrete systems to be solved, and new horizons in adaptivity. Each category is motivated by recent experiences in computational aerodynamics at the 1 Teraflop/s scale. C1 Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. Lawrence Livermore Natl Lab, Inst Sci Comp Res, Livermore, CA 94551 USA. NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Hampton, VA 23681 USA. RP Keyes, DE (reprint author), Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. EM keyes@icase.edu NR 8 TC 4 Z9 4 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67956-1 J9 LECT NOTES COMPUT SC PY 2000 VL 1900 BP 1 EP 17 PG 17 WC Computer Science, Theory & Methods SC Computer Science GA BY35X UT WOS:000189042500001 ER PT S AU Stoica, A Zebulum, R Keymeulen, D AF Stoica, A Zebulum, R Keymeulen, D BE Miller, J Thompson, A Thomson, P Fogarty, TC TI Mixtrinsic evolution SO EVOLVABLE SYSTEMS: FROM BIOLOGY TO HARDWARE, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Evolvable Systems (ICES 2000) CY APR 17-19, 2000 CL EDINBURGH, SCOTLAND SP Xilinx Inc, CyberLife, EvoNet, EvoElec Working Grp, Inst Electr Engineers, Univ Sussex, Univ Birmingham, Napier Univ AB Evolvable hardware (EHW) refers to automated synthesis/optimization of HW (e.g. electronic circuits) using evolutionary algorithms. Extrinsic EHW refers to evolution using software (SW) simulations of HW models, while intrinsic EHW refers to evolution with HW in the loop, evaluating directly the behavior/response of HW. For several reasons (including mismatches between models and physical HW, limitations of the simulator and testing system, etc.) circuits evolved in SW may not perform the same way when implemented in HW, and vice-versa. This portability problem limits the applicability of SW evolved solutions, and on the other hand, prevents the analysis (in SW) of solutions evolved in HW. This paper introduces a third approach to EHW called mixtrinsic EHW (MEHW). In MEHW evolution takes place with hybrid populations in which some individuals are evaluated intrinsically and some extrinsically, within the same generation or in consecutive ones. A set of experiments using a Field Programmable Transistor Array (FPTA) architecture is presented to illustrate the portability problem, and to demonstrate the efficiency of mixtrinsic EHW in solving this problem. C1 CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, Pasadena, CA 91109 USA. RP Stoica, A (reprint author), CALTECH, Jet Prop Lab, Ctr Integrated Space Microsyst, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67338-5 J9 LECT NOTES COMPUT SC PY 2000 VL 1801 BP 208 EP 217 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BT02V UT WOS:000171691900021 ER PT S AU Zebulum, RS Stoica, A Keymeulen, D AF Zebulum, RS Stoica, A Keymeulen, D BE Miller, J Thompson, A Thomson, P Fogarty, TC TI A flexible model of a CMOS field programmable transistor array targeted for hardware evolution SO EVOLVABLE SYSTEMS: FROM BIOLOGY TO HARDWARE, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Conference on Evolvable Systems (ICES 2000) CY APR 17-19, 2000 CL EDINBURGH, SCOTLAND SP Xilinx Inc, CyberLife, EvoNet, EvoElec Working Grp, Inst Electr Engineers, Univ Sussex, Univ Birmingham, Napier Univ ID ANALOG AB This article focuses on the properties of a fine grained reconfigurable transistor array currently under test at the Jet Propulsion Laboratory (JPL). This Field Programmable Transistor Array (FPTA) is integrated on a Complementary Metal-Oxide Semiconductor (CMOS) chip. The FPTA has advantageous features for hardware evolutionary experiments when compared to programmable circuits with a coarse level of granularity. Although this programmable chip is configured at a transistor level, its architecture is flexible enough to implement standard analog and digital circuits' building blocks with a higher level of complexity. This model and a first set of evolutionary experiments have been recently introduced. Here, the objective is to further illustrate its flexibility and versatility for the implementation of a variety of circuits in comparison with other models of re-configurable circuits. New evolutionary experiments are also presented, serving as a basis for the authors to devise an improved model for the FPTA, to be fabricated In the near future. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zebulum, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67338-5 J9 LECT NOTES COMPUT SC PY 2000 VL 1801 BP 274 EP 283 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BT02V UT WOS:000171691900027 ER PT S AU Okamura, AM Costa, MA Turner, ML AF Okamura, AM Costa, MA Turner, ML BE Corke, P Trevelyan, J TI Haptic surface exploration SO EXPERIMENTAL ROBOTICS VI SE LECTURE NOTES IN CONTROL AND INFORMATION SCIENCES LA English DT Article; Proceedings Paper CT 6th International Symposium on Experimental Robotics CY MAR 26-28, 1999 CL SYDNEY, AUSTRALIA AB We describe research at the Stanford Dextrous Manipulation Lab centered around haptic exploration of objects with robot hands. The research areas include object acquisition and manipulation and object exploration with robot fingers to measure surface features, textures and friction. We assume that the robot is semi-autonomous; it can receive guidance or supervision from humans regarding object selection and grasp choice, but is also equipped with algorithms for autonomous fine manipulation, surface exploration and feature identification. The applications of this work include object retrieval and identification in remote or hazardous environments. C1 Dextrous Manipulat Lab, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Intelligent Mechanisms Grp, Moffett Field, CA 94035 USA. RP Okamura, AM (reprint author), Dextrous Manipulat Lab, Stanford, CA 94305 USA. NR 17 TC 7 Z9 8 U1 0 U2 1 PU SPRINGER-VERLAG, LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING, SURREY, ENGLAND GU7 1NH SN 0170-8643 BN 1-85233-210-7 J9 LECT NOTES CONTR INF PY 2000 VL 250 BP 423 EP 432 PG 10 WC Automation & Control Systems; Computer Science, Information Systems SC Automation & Control Systems; Computer Science GA BP75M UT WOS:000086068500041 ER PT S AU Newman, JC Reuter, WG Aveline, CR AF Newman, JC Reuter, WG Aveline, CR BE Jerina, KL Paris, PC TI Stress and fracture analyses of semi-elliptical surface cracks SO FATIGUE AND FRACTURE MECHANICS: 30TH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 30th National Symposium on Fatigue and Fracture Mechanics CY JUN 23-25, 1998 CL WASHINGTON UNIV, ST LOUIS, MO HO WASHINGTON UNIV DE surface cracks; fracture; stress-intensity factor; finite-element analysis; constraint; elasticity; plasticity; steel ID CONSTRAINT; PLATES AB The present paper concentrates on both elastic and elastic-plastic finite-element stress analyses of the surface crack in a plate subjected to tension and bending loads. Stress-intensity factor (K) equations that cover a wider range of crack-length-to-width ratios, than those previously developed by Newman and Raju, for various crack-depth-to-crack-length ratios and crack-depth-to-plate-thickness ratios have been developed and are presented. These equations are used in the subsequent fracture anal; yses of surface crack specimens subjected to tension and bending loads. From elastic-plastic finite-element analyses, the variations of a hyper-local constraint parameter (alpha(h)) along the surface-crack front were studied to identify the region of maximum constraint and the critical fracture location. (The hyper-local constraint parameter is based on the average normal stresses acting over the plastic-zone region on a line in the crack plane perpendicular to the crack front.) The application of linear-elastic fracture mechanics to fracture of surface-crack specimens made of a high-strength D6AC steel are presented for both tension and bending loads. Two methods were used to characterize fracture: the K-2-integral around the crack front and K at a critical fracture location (phi(c)). The critical fracture location was the location of the maximum of the product of K times alpha(h), These two methods were used to evaluate the fracture toughness for both the crack initiation loads and at the maximum failure load conditions. For tension and bending loads, the K-2-integral method correlated 90% of the fracture data within +/-25% in terms of load, whereas K at the critical fracture location correlated the data within +/-20%. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, MS 188E, Hampton, VA 23681 USA. NR 23 TC 3 Z9 3 U1 1 U2 2 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2617-4 J9 AM SOC TEST MATER PY 2000 VL 1360 BP 403 EP 423 DI 10.1520/STP13417S PG 21 WC Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Engineering; Mechanics; Materials Science GA BP43D UT WOS:000085119500027 ER PT S AU Glaessgen, EH Raju, IS Poe, CC AF Glaessgen, EH Raju, IS Poe, CC BE Jerina, KL Paris, PC TI A plate element-based model for mixed-mode debonding of composite stitched stiffened panels SO FATIGUE AND FRACTURE MECHANICS: 30TH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 30th National Symposium on Fatigue and Fracture Mechanics CY JUN 23-25, 1998 CL WASHINGTON UNIV, ST LOUIS, MO HO WASHINGTON UNIV DE woven composites; stitching; stiffener debonding; plate finite elements; VCCT AB An analysis based on plate finite elements and the virtual crack closure technique is used to study the effect of stitching on Mode I and Mode II strain energy release rates for a stitched warp knit composite debond configuration. The stitches were modeled as discrete nonlinear fastener elements with a compliance determined by experiment. The axial and shear behavior of the stitches was considered with both the compliances and failure lends assumed to be independent. The effect of model slenderness ratio on the accuracy of the strain energy release rates determined with the plate element models for configurations without stitching was determined by comparison with similar plane strain models. The analysis showed that stitches are very effective in reducing Mode I strain energy release rate, G(I), by closing the debond faces near the debond front; however, they are less effective in reducing the Mode II strain energy release rate, G(II). C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Glaessgen, EH (reprint author), NASA, Langley Res Ctr, MS 188E, Hampton, VA 23681 USA. NR 31 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2617-4 J9 AM SOC TEST MATER PY 2000 VL 1360 BP 456 EP 472 DI 10.1520/STP13420S PG 17 WC Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Engineering; Mechanics; Materials Science GA BP43D UT WOS:000085119500030 ER PT S AU Newman, JC AF Newman, JC BE Halford, GR Gallagher, JP TI Irwin's stress intensity factor - A historical perspective SO FATIGUE AND FRACTURE MECHANICS: 31ST VOL SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 31st Symposium on Fatigue and Fracture Mechanics CY JUN 21-24, 1999 CL CLEVELAND, OH SP Amer Soc Testing & Mat Comm E08 DE cracks; fatigue; fatigue crack growth; fracture mechanics; stress-intensity factor; crack closure; plasticity; constraint ID SURFACE CRACKS; FRACTURE AB This paper is written to honor Dr. George R. Irwin and reviews several key developments in fracture mechanics based on his "stress-intensity factor" concept. The early development of two fundamental crack solutions, (1) an edge crack in a semi-infinite body and (2) the surface crack. are highlighted. Applications of Irwin's early concepts by other researchers to characterize fatigue-crack growth and brittle fracture of metallic materials are presented. The stress-intensity factor is the cornerstone of the damage-tolerance and durability design concepts used by the aerospace community around the world. The stress-intensity factor concept, crack-closure mechanics. and the observation that "fatigue is crack propagation" in many engineering materials has led to a merger of fatigue and fracture mechanics analysis methodologies. Irwin's recognition of the importance of the normal stress parallel to the crack (now referred to as the T-stress) in fracture led many to propose a two-parameter characterization for fracture. The importance of constraint on crack-tip yielding has been further advanced by the use of high-powered computers to calculate a normal-stress constraint parameter following his ideas. The father of fracture mechanics has left a legacy that will endure and provide safer and more reliable structures in the future. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, MS 188E, Hampton, VA 23681 USA. NR 53 TC 0 Z9 0 U1 2 U2 3 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2868-1 J9 AM SOC TEST MATER PY 2000 VL 1389 BP 39 EP 53 DI 10.1520/STP14792S PG 15 WC Engineering, Mechanical SC Engineering GA BR58R UT WOS:000166855300002 ER PT S AU Gabb, TP Bonacuse, PJ Ghosn, LJ Sweeney, JW Chatterjee, A Green, KA AF Gabb, TP Bonacuse, PJ Ghosn, LJ Sweeney, JW Chatterjee, A Green, KA BE Halford, GR Gallagher, JP TI Assessments of low cycle fatigue behavior of powder metallurgy alloy U720 SO FATIGUE AND FRACTURE MECHANICS: 31ST VOL SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 31st Symposium on Fatigue and Fracture Mechanics CY JUN 21-24, 1999 CL CLEVELAND, OH SP Amer Soc Testing & Mat Comm E08 DE superalloy; powder metallurgy; low cycle fatigue; inclusions; facets AB The fatigue lives of modern powder metallurgy disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary as functions of variables the different steps of materials/component processing: powder atomization, consolidation, extrusion, forging, heat treating, and machining [1-4]. It is important to understand the relationship between the statistical variations in life and these variables, as well as the change in life distribution due to changes in fatigue loading conditions. The objective of this study was to investigate these relationships in a nickel-base disk superalloy, U720, produced using powder metallurgy processing. Multiple strain-controlled fatigue tests were performed at 538 degreesC (1000 degreesF) at limited sets of test conditions. Analyses were performed to: (1) assess variations of microstructure, mechanical properties, and LCF failure initiation sites as functions of disk processing and loading conditions: and (2) compare mean and minimum fatigue life predictions using different approaches for modeling the data from assorted test conditions. Significant variations in life were observed as functions of the disk-processing variables evaluated. However, the lives of all specimens could still be combined and modeled together. The failure initiation sites for tests performed at a strain ratio R-epsilon = epsilon (min)/epsilon (max) of 0 were different from those in tests at a strain ratio of -1. An approach could still be applied to account for the differences in mean and maximum stresses and strains. This allowed the data in tests of various conditions to be combined for more robust statistical estimates of mean and minimum lives. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Gabb, TP (reprint author), NASA, Glenn Res Ctr, Mail Stop 49-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 12 TC 7 Z9 7 U1 0 U2 4 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2868-1 J9 AM SOC TEST MATER PY 2000 VL 1389 BP 110 EP 127 DI 10.1520/STP14797S PG 18 WC Engineering, Mechanical SC Engineering GA BR58R UT WOS:000166855300007 ER PT S AU Seshadri, BR Newman, JC AF Seshadri, BR Newman, JC BE Halford, GR Gallagher, JP TI Residual strength analyses of riveted lap-splice joints SO FATIGUE AND FRACTURE MECHANICS: 31ST VOL SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 31st Symposium on Fatigue and Fracture Mechanics CY JUN 21-24, 1999 CL CLEVELAND, OH SP Amer Soc Testing & Mat Comm E08 DE lap-splice joint; rivets; cracks; crack growth; crack-tip-opening angle; buckling; multiple-site damage cracking; STAGS shell code ID SHEET; CTOA AB integrity of fuselage structures. The existence of small cracks emanating from adjacent rivet holes in a fuselage lap-splice joint is of major concern. The residual strength of a panel with a lead crack is greatly reduced by the presence of smaller collinear cracks compared to that of only a lead crack. Recent studies in predicting the residual strength of hat and curvilinear panels with riveted lap-splice joints gave quite encouraging results, but some difficulties arose in modeling small cracks at rivet-loaded holes. Thus, there was a need to conduct detailed fracture analyses of the crack-linkup phenomenon in lap-splice joints with rivet-loaded fasteners. The objective of this paper was to analyze the crack-linkup behavior in riveted-stiffened lap-splice joint panels with small MSD cracks at several adjacent rivet holes. Analyses were based on the STAGS (STructural Analysis of General Shells) code with the critical crack-tip-opening angle (CTOA, Psi (c)) fracture criterion. To account for high constraint around a crack front, the "plane strain" core option in STAGS was used. The importance of modeling rivet flexibility with fastener elements that accurately model load transfer across the joint was discussed. Fastener holes were not modeled, but rivet connectivity was accounted for by attaching rivets to the sheet on one side of the cracks that simulated both the rivet diameter and MSD cracks. Residual strength analyses made on 2024-T3 alloy (1.6-mm thick) riveted-lap-splice joints with a lead crack and various-size MSD cracks were compared with test data from Boeing. Analyses were conducted for both restrained and unrestrained against buckling conditions. Comparison of these analyses with lap-splice-joint test panels, which were partially restrained against buckling, was generally bounded by the restrained and unrestrained failure loads. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Seshadri, BR (reprint author), NASA, Langley Res Ctr, MS 188E, Hampton, VA 23681 USA. NR 24 TC 3 Z9 3 U1 1 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2868-1 J9 AM SOC TEST MATER PY 2000 VL 1389 BP 486 EP 504 DI 10.1520/STP14817S PG 19 WC Engineering, Mechanical SC Engineering GA BR58R UT WOS:000166855300027 ER PT S AU Newman, JC AF Newman, JC BE Newman, JC Piascik, RS TI Analyses of fatigue crack growth and closure near threshold conditions for large-crack behavior SO FATIGUE CRACK GROWTH THRESHOLDS, ENDURANCE LIMITS, AND DESIGN SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT Symposium on Fatigue Crack Growth Thresholds, Endurance Limits, and Design CY NOV 04-05, 1998 CL NORFOLK, VA SP Amer Soc Testing & Mat, Comm E8 Fatigue & Fracture DE fatigue crack growth; thresholds; fracture mechanics; cracks; stress-intensity factor; crack closure; plasticity; constraint AB A plasticity-induced crack-closure model was used to study fatigue crack growth and closure in a thin-sheet; 2024-T3 aluminum alloy under threshold and constant-K-max testing procedures. Two methods of calculating crack-opening stresses were compared: one based on contact-K analyses and the ether on contact crack-opening displacement (GOD) analyses. These methods gave nearly identical results under constant-amplitude loading but under load-reduction (threshold) simulations the contact-K K analyses gave lower crack-opening stresses than the contact-GOD method. Crack-growth load-reduction simulations showed that remote Closure (crack surface contact away from the crack tip) can cause a rapid rise in opening stresses in, the near threshold regime for low-constraint (plane-stress) conditions and high applied stress levels for both low and high stress ratios. Under low applied stress levels and high constraint (near plane-strain) conditions, a rise in crack-opening stresses was not observed near the threshold regime. But the residual crack-tip-opening :displacements (CTOD) were of the order of measured oxide thicknesses in the 2024 alloy. In contrast, under constant-K-max testing, the CTOD near threshold were an order-of-magnitude larger than measured oxide thicknesses. Residual-plastic deformations were much larger than the expected oxide thicknesses. Thus, residual-plastic deformations, in addition to oxides and roughness, play an integral part in threshold development. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 30 TC 21 Z9 21 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2624-7 J9 AM SOC TEST MATER PY 2000 VL 1372 BP 227 EP 251 DI 10.1520/STP13436S PG 25 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA BP76C UT WOS:000086081800014 ER PT J AU Newman, JC Wu, XR Swain, MH Zhao, W Phillips, EP Ding, CF AF Newman, JC Wu, XR Swain, MH Zhao, W Phillips, EP Ding, CF TI Small-crack growth and fatigue life predictions for high-strength aluminium alloys. Part II: crack closure and fatigue analyses SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE surface cracks; corner cracks; crack closure; small cracks; aluminium alloy; spectrum loading ID STRESS INTENSITY FACTORS; NOTCH AB Small-crack effects were investigated in two high-strength aluminium alloys: 7075-T6 bare and LC9cs clad aluminium alloys. Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks. In the experimental program, fatigue and small-crack tests were conducted on single-edge-notch tension (SENT) specimens and large-crack tests were conducted on middle-crack tension specimens under constant-amplitude and Mini-TWIST spectrum loading. A pronounced small-crack effect was observed in both materials, especially for the negative stress ratios. For all loading conditions, most of the fatigue life of the SENT specimens was shown to be crack propagation from initial material defects or from the cladding layer. In the analysis program, three-dimensional finite-element and weight-function methods were used to determine stress intensity factors, and to develop equations for surface and corner cracks at the notch in the SENT specimen. (Part I was on the experimental and fracture mechanics analyses and was published in Fatigue Fract. Engng Mater. Struct. 21, 1289-1306, 1998.) This part focuses on a crack closure and fatigue analysis of the data presented in Part I. A plasticity-induced crack-closure model was used to correlate large-crack growth rate data to develop the baseline effective stress intensity factor range (Delta K-eff) against rate relations for each material, ignoring the large-crack threshold. The model was then used with the Delta K-eff rate relation and the stress intensity factors for surface or corner cracks to make fatigue life predictions. The initial defect sizes chosen in the fatigue analyses were similar to those that initiated failure in the specimens. Predicted small-crack growth rates and fatigue lives agreed well with experiments. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Beijing Inst Aeronaut Mat, Beijing 100095, Peoples R China. Lockheed Martin Engn & Sci Corp, Hampton, VA 23681 USA. RP Newman, JC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 28 TC 33 Z9 43 U1 4 U2 21 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD JAN PY 2000 VL 23 IS 1 BP 59 EP 72 PG 14 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 286TK UT WOS:000085461600006 ER PT B AU Visser, W Havelund, K Brat, G Park, SJ AF Visser, W Havelund, K Brat, G Park, SJ GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Model checking programs SO FIFTEENTH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 15th IEEE International Conference on Automated Software Engineering (ASE 2000) CY SEP 11-15, 2000 CL GRENOBLE, FRANCE SP Univ Joseph Fourier, IEEE Comp Soc, ACM SIGART, ACM SIGSOFT AB The majority of work carried out in the formal methods community throughout the last three decades has (for goad reasons) been devoted to special languages designed to make it easier to experiment with mechanized formal methods such as theorem provers and model checkers. In this paper I-ve will attempt to give convincing arguments for why we believe it is time for the formal methods community to shift some of its attention towards the analysis of programs written in modem programming languages. In keeping with this philosophy we have developed a verification and testing environment for Java, Java PathFinder (JPF), which integrates model checking program analysis and testing. Part of this work has consisted of building a new Java Virtual Machine that interprets Java bytecode. JPF uses state compression to handle big states, and partial order reduction, slicing, abstraction, and runtime analysis techniques to reduce the state space. JPF has been applied to a real-time avionics operating system developed at Honeywell, illustrating an intricate error and to a model of a spacecraft controller illustrating the combination of abstraction, runtime analysis, and slicing with model checking. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. RP Visser, W (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. EM wvisser@ptolemy.arc.nasa.gov; havelund@ptolemy.arc.nasa.gov; brat@ptolemy.arc.nasa.gov; spark@ptolemy.arc.nasa.gov NR 43 TC 77 Z9 77 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0710-7 PY 2000 BP 3 EP 11 PG 9 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BQ87Y UT WOS:000089913800001 ER PT B AU Menzies, T Sinsel, E AF Menzies, T Sinsel, E GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Practical large scale what-if queries: Case studies with software risk assessment SO FIFTEENTH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 15th IEEE International Conference on Automated Software Engineering (ASE 2000) CY SEP 11-15, 2000 CL GRENOBLE, FRANCE SP Univ Joseph Fourier, IEEE Comp Soc, ACM SIGART, ACM SIGSOFT DE machine learning; ensemble learning; Monte-Carlo simulations; risk assessment; COCOMO-II; decision support systems ID MODELS AB When a lack of data inhibits decision making, large scale what-if queries can be conducted over the uncertain parameter ranges. Such what-if queries can generate an overwhelming amount of data. We describe here a general method for understanding that data. Large scale what-if queries can guide Monte Carlo simulations of a model. Machine learning can then be used to summarize the output. The summarization is an ensemble of decision trees. The TARZAN system can poll the ensemble looking for majority conclusions regarding what factors change the classifications of the data. TARZAN can succinctly present the results from very large what-if queries. For example, in one of the studies presented here, we can view on 1/2 a page the significant features from 10(9) what-ifs. C1 NASA, WVU IV&V Facil, Fairmont, WV 26554 USA. RP Menzies, T (reprint author), NASA, WVU IV&V Facil, 100 Univ Dr, Fairmont, WV 26554 USA. NR 18 TC 4 Z9 4 U1 0 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0710-7 PY 2000 BP 165 EP 173 DI 10.1109/ASE.2000.873661 PG 9 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BQ87Y UT WOS:000089913800017 ER PT B AU Feather, MS Cornford, SL Larson, TW AF Feather, MS Cornford, SL Larson, TW GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Combining the best attributes of qualitative and quantitative risk management tool support SO FIFTEENTH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 15th IEEE International Conference on Automated Software Engineering (ASE 2000) CY SEP 11-15, 2000 CL GRENOBLE, FRANCE SP Univ Joseph Fourier, IEEE Comp Soc, ACM SIGART, ACM SIGSOFT AB Tools have been developed that support risk identification and management activities during different phases of a project lifecycle. For the earlier stages of the project lifecycle, a tool for qualitative identification and manipulation of risk and risk mitigation data was developed. For the later stages of the lifecycle, a separate tool for quantitative manipulation of requirements, risk and risk mitigation data was developed. These two tools were then combined into a single tool. The combination of these qualitative and quantitative risk management tools is the focus of this paper. The combination was first envisioned as simple a convenience, ensuring that the results from the early lifecycle risk management would flow smoothly into the later lifecycle management. However, it was found that the combination led to the possibility of extending many of the capabilities of each tool into th other tool's phases. The net result is a combination that exhibits the best attributes of both qualitative and quantitative risk management tool support. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Feather, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0710-7 PY 2000 BP 309 EP 312 DI 10.1109/ASE.2000.873685 PG 4 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BQ87Y UT WOS:000089913800041 ER PT S AU Gehrels, N Shrader, C AF Gehrels, N Shrader, C BE McConnell, ML Ryan, JM TI Status of the compton gamma ray observatory SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB The Compton Gamma Ray Observatory and three of its four experiment packages continue to function in a nearly flawless manner now well into the eighth year of mission operations. Only the EGRET instrument is operating with reduced capability due mainly to the depleted spark-chamber gas, but it is nonetheless still expected to make significant contributions, notably in the area of Solar flares and AGN variability. We discuss the status of the mission as of mid-1999 as well as the prospects of an extended mission tasting well into the first decade of the next century. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 3 EP 10 PG 8 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800001 ER PT S AU Harris, MJ Teegarden, BJ Cline, TL Gehrels, N Palmer, DM Ramaty, R Seifert, H AF Harris, MJ Teegarden, BJ Cline, TL Gehrels, N Palmer, DM Ramaty, R Seifert, H BE McConnell, ML Ryan, JM TI TGRS measurements of the positron annihilation spectrum from the Galactic center SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID SPECTROMETER; LINE AB The TGRS experiment on board the Wind spacecraft includes a Ge detector with very high resolution (3-4 keV FWHM) at energies around 511 keV. To take advantage of WIND's fixed pointing at the south ecliptic pole and its 3 s rotation, TGRS also includes a Pb occulter fixed on the spacecraft body subtending an are of 90 degrees along the ecliptic plane. Spectra of the Galactic center region, identified by this occultation method, have been accumulated since 1994 November. In this paper we present updated results for the Galactic center positron annihilation line from these occulted spectra. From the results prior to fall 1997 we obtained the intensity, width, energy and variability of the line, the positronium (Ps) fraction, and limited information about the spatial distribution of the line, all of which have been published. Since the fall of 1997, degradation of the instrument performance has limited us to improving our results for the spatial distribution. These updated results are in marginal disagreement (similar to 2.5 sigma) with a model based on earlier OSSE measurements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harris, MJ (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 31 EP 34 PG 4 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800004 ER PT S AU Harris, MJ Palmer, DM Naya, JE Teegarden, BJ Cline, TL Gehrels, N Ramaty, R Seifert, H AF Harris, MJ Palmer, DM Naya, JE Teegarden, BJ Cline, TL Gehrels, N Ramaty, R Seifert, H BE McConnell, ML Ryan, JM TI TGRS observations of positron annihilation in classical novae SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID SPECTROMETER AB The TGRS experiment on board the I Wind spacecraft has many advantages as a sky monitor - broad field of view (similar to 2 pi centered on the south ecliptic pole), long life (1994-present), and stable low background and continuous coverage due to Wind's high altitude high eccentricity orbit. The Ge detector has sufficient energy resolution (3-4 keV at 511 keV) to resolve a cosmic positron annihilation line from the strong background annihilation line from P-decays induced by cosmic ray impacts on the instrument, if the cosmic line is Doppler-shifted by this amount. Such lines (blueshifted) are predicted from nucleosynthesis in classical novae. We have searched the entire TGRS database for 1995-1997 for this line, with negative results. In principle such a search could yield an unbiased upper limit on the highly-uncertain Galactic nova rate. We carefully examined the times around the known nova events during this period, also with negative results. The upper limit on the nova line Aux in a 6-hr interval is typically < 3.8 x 10(-3) photon cm(-2) s(-1) (4.6 sigma). We performed the same analysis for times around the outburst of Nova Vel 1999, obtaining a worse limit due to recent degradation of the detector response caused by cosmic ray induced damage. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harris, MJ (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 87 EP 91 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800016 ER PT S AU Shrader, CR Titarchuk, LG AF Shrader, CR Titarchuk, LG BE McConnell, ML Ryan, JM TI Physical parameter estimation in black hole X-ray binaries SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID HIGH-ENERGY SPECTRA AB We describe a method for extracting physical information on black-hole binaries systems from their X- and gamma-ray spectral properties. The high-energy continuum is interpreted as thermal emission from an accretion disk and Comptonized emission from a relativistic bulk inflow. Application of this methodology to recent X- and gamma ray observations are presented, with emphasis on the recently discovered S-ray nova XTE J1550-564. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Shrader, CR (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 148 EP 152 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800028 ER PT S AU Wilson, CA Finger, MH Scott, DM AF Wilson, CA Finger, MH Scott, DM BE McConnell, ML Ryan, JM TI GRO J2058+42 observations with BATSE and RXTE SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB GRO J2058+42 is a 196-second pulsar discovered with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma-Ray Observatory (CGRO) during a giant outburst in 1995. It underwent a series of 9 weaker outbursts from 1995 to 1997 that alternated in peak pulsed intensity, with a 110-day cycle in the 20-50 keV band [4]. These outbursts did not show the same intensity variations in the 2-10 keV observations with the Rossi X-ray Timing Explorer's (RXTE) All-Sky Monitor (ASM) [2]. Additional outbursts after this series were observed with BATSE and with the RXTE Proportional Counter Array (PCA) and ASM [3]. These outbursts do not appear to continue the alternating peak pulsed intensity pattern seen with BATSE in the first 9 outbursts. Histories of pulse frequency, pulsed flux, and total flux are presented. Pulse profiles and spectra from PCA observations are also presented. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Dept SD50, Huntsville, AL 35812 USA. RP Wilson, CA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Dept SD50, Huntsville, AL 35812 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 208 EP 212 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800040 ER PT S AU Nayakshin, S Kazanas, D Kallman, TR AF Nayakshin, S Kazanas, D Kallman, TR BE McConnell, ML Ryan, JM TI Thermal instability and photoionized X-ray reflection in accretion disks SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID ACTIVE GALACTIC NUCLEI; COLD MATTER; SPECTRA; BINARIES; CORONA AB We study the illumination of accretion disks in the vicinity of compact objects by an overlying X-ray source. Our approach differs from previous works of the subject in that we relax the simplifying assumption of constant gas density used in these studies; instead we determine the density from hydrostatic balance which is solved simultaneously with the ionization balance and the radiative transfer in a plane-parallel geometry. We find that the self-consistent density determination makes evident the presence of a thermal ionization instability. The main effect of this instability is to prevent the illuminated gas from attaining temperatures at which the gas is unstable to thermal perturbations. In sharp contrast to the constant density calculations that predict a continuous and rather smooth variation of the gas temperature in the illuminated material we find that the temperature profile consists of several well defined thermally stable layers. In particular, the uppermost layers of the X-rap illuminated gas are found to be almost completely ionized and at the local Compton temperature (similar to 10(7) - 10(8) K); at larger depths, the gas temperature drops abruptly to form a thin layer with T similar to 10(6) K, while at yet larger depths it decreases sharply to the disk effective temperature. The results of our self-consistent calculations are both quantitatively and qualitatively different from those obtained using the constant density assumption. We believe that usage of the latter can be completely misleading in attempts to understand the accretion disk structure from observations of iron lines and the reflection component. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Nayakshin, S (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 250 EP 254 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800049 ER PT S AU Zhang, B Harding, AK AF Zhang, B Harding, AK BE McConnell, ML Ryan, JM TI Gamma-ray and X-ray luminosities from spin-powered pulsars in the full polar cap cascade model SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB We modify the conventional curvature radiation (inverse Compton scattering) + synchrotron radiation polar cap cascade model by including the inverse Compton scattering of the higher generation pairs. Within the framework of the space-charge-limited-flow acceleration model with frame-dragging proposed by Harding & Muslimov (1998), such a full polar cap cascade scenario can well reproduce the L-gamma proportional to (L-sd)(1/2) and the L-x similar to 10(-3)L(sd) dependences observed from the known spin-powered pulsars. According to this model, the "pulsed" soft ROSAT-band X-rays from most of the millisecond pulsars might be of thermal origin, if there are no strong multipole magnetic components near their surfaces. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Zhang, B (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Harding, Alice/D-3160-2012 NR 13 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 272 EP 276 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800053 ER PT S AU Piner, BG Edwards, PG Wehrle, AE Hirabayashi, H Lovell, JEJ Unwin, SC AF Piner, BG Edwards, PG Wehrle, AE Hirabayashi, H Lovell, JEJ Unwin, SC BE McConnell, ML Ryan, JM TI Space VLBI Observations of 3C 279 at 1.6 and 5 GHz SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID QUASAR 3C-279 AB We present the results of VLBI Space Observatory Programme (VSOP) observations of the gamma-ray blazar 3C 279 at 1.6 and 5 GHz from January 1998. The combination of the VSOP and VLBA-only images at these two frequencies maps the jet structure on scales from 1 to 100 mas. A spectral index map was made by combining the VSOP 1.6 GHz image with a matched-resolution VLBA-only image at 5 GHz from our VSOP observation on the following day. The spectral index map shows the core to have a highly inverted spectrum, with some areas having a spectral index approaching the limiting value for synchrotron self-absorbed radiation of +2.5 (S proportional to nu(alpha)). Gaussian model fits to the VSOP visibilities reveal high brightness temperatures (> 10(12) K) that are difficult to measure with ground-only arrays. An extensive error analysis was performed on the brightness temperature measurements. Most components did not have measurable brightness temperature upper limits, but lower limits were measured as high as 5 x 10(12) K. This lower limit is significantly above both the nominal inverse Compton and equipartition brightness temperature limits. The derived Doppler factor in the case of the equipartition limit is at the upper end of the range of expected values for EGRET blazars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Piner, BG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 308 EP 312 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800059 ER PT S AU Nayakshin, S AF Nayakshin, S BE McConnell, ML Ryan, JM TI On the X-ray heated skin of accretion disks SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID ACTIVE GALACTIC NUCLEI; REFLECTION SPECTRA; BINARIES; PROFILES; CORONA; LINES AB We present a simple analytical formula for the Thomson depth of the Xray heated skin of accretion disks valid at any radius and for a broad range of spectral indices of the incident X-raps, arbitrary geometry of the S-ray source, accretion rates and black hole masses. We expect that this formula may find useful applications in studies of geometry of the inner part of accretion flows around compact objects, and in several other astrophysically important problems, such as the recently observed X-ray "Baldwin" effect (i.e., monotonic decrease of Fe line's equivalent width with the S-ray luminosity of AGN), the problem of missing Lyman edge in AGN, and line and continuum variability studies in accretion disks around compact objects. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Nayakshin, S (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 440 EP 444 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800086 ER PT S AU Watanabe, K Leising, MD Share, GH Kinzer, RL AF Watanabe, K Leising, MD Share, GH Kinzer, RL BE McConnell, ML Ryan, JM TI The MeV cosmic gamma-ray background measured with SMM SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID SUPERNOVAE; RADIATION AB Given the Solar Maximum Mission (SMM) Gamma-Ray Spectrometer's (GRS) nine years of exposure and large field of view, its data contain a tremendously significant signal from the isotropic cosmic gamma-ray background (CGB) in the energy range 0.3 - 8.0 MeV. We have extracted this signal by modeling ifs modulation by the Earth's motion through the GRS field of view, along with several other background components, such as from the SAA and Earth Albedo gamma rays. We can quantify the success of the technique and evaluate possible systematic errors because we have many independent measurements of the CGB, which should be constant in time, and because all known other background components have narrow lines that should not be present in the CGB. Ne thus obtain the definitive measurement of the CGB in this energy range to date. We compare the CGB spectrum with line emission from iron production in thermonuclear supernovae, and conclude that some other source(s) probably dominate the 1 MeV region. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Watanabe, K (reprint author), NASA, Goddard Space Flight Ctr, Code 661-0, Greenbelt, MD 20771 USA. NR 11 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 471 EP 475 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800091 ER PT S AU Thompson, DJ Bertsch, DL Hartman, RC Collmar, W Johnson, WN AF Thompson, DJ Bertsch, DL Hartman, RC Collmar, W Johnson, WN BE McConnell, ML Ryan, JM TI EGRET/COIMPTEL observations of an unusual, steep-spectrum gamma-ray source SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE ID EGRET AB During analysis of sources below the threshold of the third EGRET catalog, we have discovered a source, named GRO J1400-3956 based on the best position, with a remarkably steep spectrum. Archival analysis of COMPTEL data shows that the spectrum must have a strong turn-over in the energy range between COMPTEL and EGRET. The EGRET data show some evidence of time variability, suggesting an AGN, but the spectral change of slope is larger than that seen for most gamma-ray blazars. The sharp cutoff resembles the high-energy spectral breaks seen in some gamma-ray pulsars. There have as yet been no OSSE observations of this source. C1 NASA, GSFC, Greenbelt, MD 20771 USA. RP Thompson, DJ (reprint author), NASA, GSFC, Greenbelt, MD 20771 USA. RI Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 479 EP 483 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800092 ER PT S AU Bertsch, DL Hartman, RC Hunter, SD Thompson, DJ Lin, YC Kniffen, DA Kanbach, G Mayer-Hasselwander, HA Reimer, O Sreekumar, P AF Bertsch, DL Hartman, RC Hunter, SD Thompson, DJ Lin, YC Kniffen, DA Kanbach, G Mayer-Hasselwander, HA Reimer, O Sreekumar, P BE McConnell, ML Ryan, JM TI Spectral modeling of the EGRET 3EG gamma ray sources near the Galactic Plane SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB The third EGRET catalog lists 84 sources within 10 degrees of the Galactic plane, Five of these are well-known spin-powered pulsars, 2 and possibly 3 others are blazars, and the remaining 74 are classified as unidentified although 6 of these are likely to be artifacts of nearby strong sources. Several of the remaining 68 unidentified sources have been noted as having positional agreement with supernovae remnants and OB associations. Others may be radio-quiet pulsars like Geminga, and still others may belong to a totally new class of sources, The question of the energy spectral distributions of these sources is an important clue to their identification, In this paper, the spectra of the sources within 10 degrees of Galactic plane are fit with three different functional forms; a single power law, two power laws, and a power law with an exponential cutoff. Where possible, the best fit is selected with statistical tests. Twelve, and possibly an additional 5 sources, are found to have spectra that are fit by a breaking power law or by the power law with exponential cutoff function. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bertsch, DL (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012; Reimer, Olaf/A-3117-2013 OI Thompson, David/0000-0001-5217-9135; Reimer, Olaf/0000-0001-6953-1385 NR 1 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 504 EP 508 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800097 ER PT S AU Digel, SW AF Digel, SW BE McConnell, ML Ryan, JM TI Unbinned likelihood analysis of EGRET observations SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB We present a newly-developed likelihood analysis method for EGRET data that defines the likelihood function without binning the photon data or averaging the instrumental response functions. The standard likelihood analysis applied to EGRET data requires the photons to be binned spatially and in energy, and the point-spread functions to be averaged over energy and inclination angle. The full-width half maximum of the point-spread function increases by about 40% from on-axis to 30 degrees inclination, and depending on the binning in energy can vary by more than that in a single energy bin. The new unbinned method avoids the loss of information that binning and averaging cause and can properly analyze regions where EGRET viewing periods overlap and photons with different inclination angles would otherwise be combined in the same bin. In the poster, we describe the unbinned analysis method and compare its sensitivity with binned analysis for detecting point sources in EGRET data. C1 NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Digel, SW (reprint author), NASA, Goddard Space Flight Ctr, USRA, Code 661, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 601 EP 605 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800113 ER PT S AU Thompson, DJ Bertsch, DL Hunter, SD Deines-Jones, P Dingus, BL Kniffen, DA Sreekumar, P AF Thompson, DJ Bertsch, DL Hunter, SD Deines-Jones, P Dingus, BL Kniffen, DA Sreekumar, P BE McConnell, ML Ryan, JM TI Preliminary results from a new analysis method for EGRET data SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB In order to extend the life of EGRET, the gas in the spark chamber wets allowed to deteriorate more than was originally planned for the nominal two year Compton Observatory mission. Gamma ray events are lost because the pattern recognition analysis rules are not optimized for the poorer quality data By changing the rules used by the data analysts, we can recover a significant fraction of the lost events, allowing improved statistics for detection and study of sources. Preliminary results from the Crab, Geminga, and BL Lacertae indicate the feasibility of this analysis. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thompson, DJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Hunter, Stanley/D-2942-2012; Thompson, David/D-2939-2012 OI Thompson, David/0000-0001-5217-9135 NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 606 EP 610 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800114 ER PT S AU Gehrels, N Macomb, D AF Gehrels, N Macomb, D BE McConnell, ML Ryan, JM TI Future prospects for NASA's gamma-ray astronomy program SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB In 1997, NASA convened a working group to provide input on the future of gammaray astronomy. This group, the Gamma-Ray Program Working Group or GRAPWG, was reconvened in 1998 to provide further input. This paper describes the scope and recommendations of this group. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 659 EP 666 PG 8 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800123 ER PT S AU Shrader, CR Sturner, SJ Teegarden, BJ AF Shrader, CR Sturner, SJ Teegarden, BJ BE McConnell, ML Ryan, JM TI INTEGRAL/SPI spectral deconvolution SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB The INTEGRAL Spectrometer or "SPI", is a cooled-germanium instrument covering the 20 keV to similar to 10 MeV energy range with a resolution of about 500. The unique nature of the instrument, 19 separate detector elements Viewing the: sky through a coded mask aperture, poses a number of difficulties in analyzing the data. For example, a typical observation consists of multiple pointing directions (dithering) with an instrument response that is highly directional. Multiple sources within the nominal 16 degrees FoV are likely to be common, and most high-energy point sources are variable over observable time scales. Thus a typical deconvolution of the detector count-rate data involves a complex global minimization problem over large data and parameter spaces. Strategies for dealing with these difficulties, are discussed and some preliminary results based on simulated data are presented. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Shrader, CR (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 717 EP 721 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800134 ER PT S AU Chen, A Ritz, S AF Chen, A Ritz, S BE McConnell, ML Ryan, JM TI Detecting the attenuation of blazar gamma-ray emission by extragalactic background light with GLAST SO FIFTH COMPTON SYMPOSIUM SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Compton Symposium CY SEP 15-17, 1999 CL UNIV NEW HAMPSHIRE, PORTSMOUTH, NH SP Univ New Hampshire, NASA, Goddard Space Flight Ctr, Compton Gamma-Ray Observ Sci Support Ctr HO UNIV NEW HAMPSHIRE AB Gamma rays with energy above 10 GeV interact with optical-UV photons resulting in pair production. Therefore, a large sample of high redshift sources of these gamma rays can be used to probe the extragalactic background starlight (EBL) by examining the redshift dependence of the attenuation of the flux above 10 GeV. GLAST, the next generation high-energy gamma-ray telescope, will for the first time have the unique capability to detect thousands of gamma-ray blazars up to redshifts of at least z = 4, with enough angular resolution to allow identification of a large fraction of their optical counterparts. By combining recent determinations of the gamma-ray blazar luminosity function, recent calculations of the high energy gamma-ray opacity due to EBL absorption, and the expected GLAST instrument performance to produce simulated samples of blazars that GLAST would detect, including their redshifts and fluxes, we demonstrate that these blazars have the potential to be a highly effective probe of the EBL. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chen, A (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-932-7 J9 AIP CONF PROC PY 2000 VL 510 BP 759 EP 763 PG 5 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BQ14E UT WOS:000087291800143 ER PT S AU Taleghani, B AF Taleghani, B BE Gobin, PF Friend, CM TI Validation of high displacement piezoelectric actuator finite element models SO FIFTH EUROPEAN CONFERENCE ON SMART STRUCTURES AND MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 5th European Conference on Smart Structures and Materials CY MAY 22-24, 2000 CL GLASGOW, SCOTLAND SP European Opt Soc, SPIE, Scottish Enterprise, Greater Glasgow & Clyde Valley Tourist Board, IEE, IMechE DE NASTRAN (R); ANSYS (R); finite element; THUNDER; piezoelectric; actuator AB The paper presents the results obtained by using NASTRAN(R) and ANSYS(R) finite element codes to predict doming of the THUNDER piezoelectric actuators during the manufacturing process and subsequent straining due to an applied input voltage. To effectively use such devices in engineering applications, modeling and characterization are essential. Length, width, dome height, and thickness are important parameters for users of such devices. Therefore, finite element models were used to assess the effects of these parameters. NASTRAN(R) and ANSYS(R) used different methods for modeling piezoelectric effects. In NASTRAN(R), a thermal analogy was used to represent voltage at nodes as equivalent temperatures, while ANSYS(R) processed the voltage directly using piezoelectric finite elements. The results of finite element models were validated by using the experimental results. C1 USA, NASA, Res Lab,Langley Res Ctr, Vehicle Technol Directorate, Hampton, VA 23665 USA. RP Taleghani, B (reprint author), USA, NASA, Res Lab,Langley Res Ctr, Vehicle Technol Directorate, Hampton, VA 23665 USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3710-7 J9 P SOC PHOTO-OPT INS PY 2000 VL 4073 BP 37 EP 45 DI 10.1117/12.396405 PG 9 WC Acoustics; Computer Science, Artificial Intelligence; Materials Science, Multidisciplinary; Mechanics; Robotics; Optics SC Acoustics; Computer Science; Materials Science; Mechanics; Robotics; Optics GA BR41Q UT WOS:000166341600004 ER PT B AU Lutz, RR AF Lutz, RR GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Four areas of overlapping interest SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON HIGH ASSURANCE SYSTEMS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on High Assurance Systems Engineering (HASE 2000) CY NOV 15-17, 2000 CL ALBUQUERQUE, NM SP IEEE Comp Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Lutz, RR (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0927-4 PY 2000 BP 49 EP 50 PG 2 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BR28C UT WOS:000166001800008 ER PT B AU Cukic, B Chakravarthy, D AF Cukic, B Chakravarthy, D GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Bayesian framework for reliability assurance of a deployed safety critical system SO FIFTH IEEE INTERNATIONAL SYMPOSIUM ON HIGH ASSURANCE SYSTEMS ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 5th IEEE International Symposium on High Assurance Systems Engineering (HASE 2000) CY NOV 15-17, 2000 CL ALBUQUERQUE, NM SP IEEE Comp Soc ID SOFTWARE AB The existence of software faults in safety-critical systems is not tolerable. Goals of software reliability assessment are estimating the failure probability of the program, theta, and gaining statistical confidence that theta is realistic. While in most cases reliability assessment is performed prior to the deployment of the system there are circumstances when reliability assessment is needed in the process of (re)evaluation of the fielded (deployed) system. Post deployment reliability assessment provides reassurance that the expected dependability characteristics of the system have been achieved. It may be used as a basis of the recommendation for maintenance and further improvement, or the recommendation to discontinue the use of the system. The paper presents practical problems and challenges encountered in an effort to assess and quantify software reliability of NASA's Day-of-Launch I-Load Update (DOLILU II) system DOLILU II system has been in operational use for several years. Bayesian framework is chosen for reliability assessment, because it allows incorporation of (in this specific case failure free) program executions observed in the operational environment. Furthermore, we outline the development of a probabilistic framework that allows accounting of rigorous verification and validation activities performed prior to system's deployment into the reliability assessment. C1 W Virginia Univ, Dept Comp Sci & Elect Engn, NASA, Software Res Lab, Morgantown, WV 26506 USA. RP Cukic, B (reprint author), W Virginia Univ, Dept Comp Sci & Elect Engn, NASA, Software Res Lab, Morgantown, WV 26506 USA. NR 16 TC 5 Z9 6 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0927-4 PY 2000 BP 321 EP 329 DI 10.1109/HASE.2000.895477 PG 9 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BR28C UT WOS:000166001800045 ER PT B AU Huyse, L Maes, MA AF Huyse, L Maes, MA BE Topping, BHV TI Computational homogenization techniques for plane stress elastic random fields SO FINITE ELEMENTS: TECHNIQUES AND DEVELOPMENTS LA English DT Proceedings Paper CT 5th International Conference on Computational Structures Technology/2nd International Conference on Engineering Computational Technology CY SEP 06-08, 2000 CL LEUVEN, BELGIUM AB The continuum elastic properties of a material are obtained through a homogenization process of its microstructure. A force-based homogenization technique, based on an assumed stress state inside the material, is presented in this paper. The method complements existing displacement-based techniques that are based on an assumed deformation State for the material. Since the microstructure of the material is known only in a probabilistic sense, the elastic properties of the homogenized continuum are described by means of continuous random fields. It is shown that the stochastic features of the micromechanically consistent continuum can be considerably different from those based on a straightforward randomization of the deterministic constitutive laws of elasticity. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. RP Huyse, L (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU CIVIL COMP PRESS PI EDINBURGH PA 10 SAXE-COBURG PLACE, EDINBURGH EH3 5BR, MIDLOTHIAN, SCOTLAND BN 0-948749-67-9 PY 2000 BP 319 EP 323 PG 5 WC Engineering, Civil SC Engineering GA BR26Z UT WOS:000165984200036 ER PT S AU Smith, GL Mlynczak, MG AF Smith, GL Mlynczak, MG GP ESA ESA TI CERES and GERB validation studies SO FIRST MSG RAO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st MSG RAO Workshop CY MAY 17-19, 2000 CL BOLOGNA, ITALY SP European Space Agcy, EUMETSAT C1 Virginia Polytech Inst & State Univ, Langley Res Ctr, NASA, Hampton, VA 23681 USA. RP Smith, GL (reprint author), Virginia Polytech Inst & State Univ, Langley Res Ctr, NASA, Mail Stop 420, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-649-X J9 ESA SP PUBL PY 2000 VL 452 BP 87 EP 90 PG 4 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BR53E UT WOS:000166722400017 ER PT S AU Mlynczak, M Kratz, D Mertens, C Smith, GL AF Mlynczak, M Kratz, D Mertens, C Smith, GL GP ESA ESA TI Far-infrared radiative transfer studies with GERB data SO FIRST MSG RAO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st MSG RAO Workshop CY MAY 17-19, 2000 CL BOLOGNA, ITALY SP European Space Agcy, EUMETSAT ID WATER-VAPOR; ALGORITHMS; RADIANCE; BUDGET C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Mlynczak, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-649-X J9 ESA SP PUBL PY 2000 VL 452 BP 91 EP 94 PG 4 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BR53E UT WOS:000166722400018 ER PT S AU Minnis, P Young, DF Charlock, TP Priestley, KJ Wong, T Duda, DP Loeb, NG Morcrette, JJ AF Minnis, P Young, DF Charlock, TP Priestley, KJ Wong, T Duda, DP Loeb, NG Morcrette, JJ GP ESA ESA TI Validation, calibration, and improvement of cloud and radiation parameters using MSG SEVIRI and GERB with CERES, MODIS, GOES, and triana data SO FIRST MSG RAO WORKSHOP SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st MSG RAO Workshop CY MAY 17-19, 2000 CL BOLOGNA, ITALY SP European Space Agcy, EUMETSAT ID SUCCESS C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Minnis, P (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-649-X J9 ESA SP PUBL PY 2000 VL 452 BP 95 EP 98 PG 4 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing GA BR53E UT WOS:000166722400019 ER PT B AU Hubeny, I Lanz, T Heap, S AF Hubeny, I Lanz, T Heap, S BE Weiss, A Abel, TG Hill, V TI Model atmospheres and radiatively driven winds of metal-poor stars SO FIRST STARS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT MPA/ESO Workshop on the First Stars CY AUG 04-06, 1999 CL GARCHING, GERMANY SP MPA, European So Observ AB We present a grid of non-LTE metal-line-blanketed hydrostatic model atmospheres for various effective temperatures, surface gravities (luminosities), and metallicities. The metallicities range from an essentially metal-free, primordial composition to a solar composition. For each model, we calculate the exact radiation force and compare to gravity acceleration. We thus find for each metallicity, the maximum surface gravity as a function of effective temperature required for the radiation force to exceed gravity and thus to initiate a radiatively-driven wind. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hubeny, I (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67222-2 J9 ESO ASTROPHY SYMP PY 2000 BP 133 EP 134 DI 10.1007/10719504_22 PG 2 WC Astronomy & Astrophysics; Chemistry, Inorganic & Nuclear; Physics, Nuclear SC Astronomy & Astrophysics; Chemistry; Physics GA BQ54S UT WOS:000088721200022 ER PT B AU Haiman, Z AF Haiman, Z BE Weiss, A Abel, TG Hill, V TI The radiative feedback from the first stars and quasars and the end of the dark age SO FIRST STARS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT MPA/ESO Workshop on the First Stars CY AUG 04-06, 1999 CL GARCHING, GERMANY SP MPA, European So Observ ID HUBBLE DEEP FIELD; GALAXIES AB In hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T-vir less than or similar to 10(4)K) halos that collapse before cosmological reionization. If the first collapsed halos harbor stars, then their UV flux below 13.6 eV photo-dissociates the molecular hydrogen Hz in subsequently collapsing halos within a large sphere of influence. This causes a pause in the cosmic star-formation history: the buildup of the UVB and the epoch of reionization are delayed until larger halos (Tvir greater than or similar to 10(4)K) collapse. In contrast, if the small halos harbor mini-quasars with hard spectra extending to similar to 1keV, then their X-rays balance the effects of the UVB, the negative feedback does not occur, and reionization can be caused early on by the small halos. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Haiman, Z (reprint author), NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67222-2 J9 ESO ASTROPHY SYMP PY 2000 BP 219 EP 224 DI 10.1007/10719504_42 PG 6 WC Astronomy & Astrophysics; Chemistry, Inorganic & Nuclear; Physics, Nuclear SC Astronomy & Astrophysics; Chemistry; Physics GA BQ54S UT WOS:000088721200042 ER PT B AU Williger, GM Smette, A Hazard, C Baldwin, JA McMahon, RG AF Williger, GM Smette, A Hazard, C Baldwin, JA McMahon, RG BE Weiss, A Abel, TG Hill, V TI Evidence for large scale structure in the Ly alpha forest at z > 2.6 SO FIRST STARS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT MPA/ESO Workshop on the First Stars CY AUG 04-06, 1999 CL GARCHING, GERMANY SP MPA, European So Observ AB We present a search for spatial and redshift correlations in a 2 Angstrom resolution spectroscopic survey of the Ly alpha forest at 2.15 < z < 3.37 toward ten QSOs within a 1 degrees diameter field. We find a 3.2 sigma signal for correlations of the Ly alpha absorption line wavelengths between different lines of sight over 2.60 < z < 3.26. We conclude that a significant fraction of the Ly-alpha forest arises in structures whose correlation length extends at least over 30 arcmin (similar to 26 h(-1) comoving Mpc at z = 2.6 for H-0 = 100h km s(-1) Mpc(-1), Omega = 1.0, Lambda = 0). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Williger, GM (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67222-2 J9 ESO ASTROPHY SYMP PY 2000 BP 319 EP 320 DI 10.1007/10719504_59 PG 2 WC Astronomy & Astrophysics; Chemistry, Inorganic & Nuclear; Physics, Nuclear SC Astronomy & Astrophysics; Chemistry; Physics GA BQ54S UT WOS:000088721200059 ER PT B AU Heap, SR Hubeny, I Smette, A Williger, G AF Heap, SR Hubeny, I Smette, A Williger, G BE Weiss, A Abel, TG Hill, V TI The HeII Gunn-Peterson effect SO FIRST STARS SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT MPA/ESO Workshop on the First Stars CY AUG 04-06, 1999 CL GARCHING, GERMANY SP MPA, European So Observ AB The UV background at a given redshift is representative of the starlight and QSO-light generated in earlier redshifts. It holds key information on the populations of stars and QSO's at high redshift. We have used observations of the Heir Gunn-Peterson (G-P) effect along the line of sight to Q 0302-003 at z = 3.286 to constrain the spectral energy distribution of the UV background spectrum over the redshift range, z = 2.78 - 3.28. Assuming that stars have softer spectra than do QSO's, we used the softness of the UV background to discriminate between these two possible classes of ionizing sources. We find that stars appear to be significant contributors to the UV background at z > 3, but below z = 3, there is a hardening of the UV background suggestive of an increased contribution by QSO's. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heap, SR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67222-2 J9 ESO ASTROPHY SYMP PY 2000 BP 323 EP 324 DI 10.1007/10719504_61 PG 2 WC Astronomy & Astrophysics; Chemistry, Inorganic & Nuclear; Physics, Nuclear SC Astronomy & Astrophysics; Chemistry; Physics GA BQ54S UT WOS:000088721200061 ER PT J AU Olla, BL Davis, MW Rose, C AF Olla, BL Davis, MW Rose, C TI Differences in orientation and swimming of walleye pollock Theragra chalcogramma in a trawl net under light and dark conditions: concordance between field and laboratory observations SO FISHERIES RESEARCH LA English DT Article DE behavior; bycatch; light; mortality; survival; vision ID FISH; SABLEFISH AB The success of modifications to fishing gear in reducing or eliminating bycatch mortality requires in many cases that escaping fish be able to use vision for volitional guiding out of gear. Light adequate for vision is often not present as fishing operations are commonly conducted at depths or at night when light quantity is below visual capability. Previous observations of walleye pollock behavior in the laboratory indicated that darkness inhibited their ability to respond and orient to trawling gear. The goal of the present study was to test this result in situ by comparing swimming and orientation capabilities of walleye pollock under light and dark conditions in commercial type trawl gear using infrared illumination and video cameras to monitor these behaviors. Under light conditions, fish swam actively and were oriented parallel to the principle axis of the trawl. In contrast, under dark conditions there was little or no active swimming and the fish showed a significant degree of deviation from the principle axis of the trawl. These results showed that vision plays a major role in trawl gear interactions for walleye pollock and points out the importance of measuring light quantity in field studies of bycatch processes and mortality. Published by Elsevier Science B.V. C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Olla, BL (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NR 17 TC 43 Z9 44 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JAN PY 2000 VL 44 IS 3 BP 261 EP 266 DI 10.1016/S0165-7836(99)00093-4 PG 6 WC Fisheries SC Fisheries GA 272LM UT WOS:000084651700006 ER PT S AU Waller, JM Newton, BE Beeson, HD Haas, JP AF Waller, JM Newton, BE Beeson, HD Haas, JP BE Steinberg, TA Newton, BE Beeson, HD TI Comparison of the dimensional stability of Kel-F 81 and Neoflon CTFE M400H polychlorotrifluoroethylenes used in valve seat applications SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE PCTFE; Kel-F; Neoflon; valve seats; dimensional instability; impact sensitivity; glass transition; flow friction AB The dimensional stability of polychlorotrinuoroethylene (PCTFE) valve seats used in gas cylinder regulator applications was evaluated by thermomechanical analysis (TMA). Testing focused on two commercial grades of PCTFE, Kel-F(R)(4) 81 and Neoflon(R)4 CTFE M400H, and on actual PCTFE valve seats obtained from different manufacturers. The effects of resin grade, percent crystallinity, and process history on TMA deflection were evaluated. TMA results frequently showed low-temperature dimensional instability between 40 and 70 degreesC. The corresponding permanent height change resulting from brief cyclic heating of as-received material to 150 degreesC ranged from to +3.9 to -8.5 percent. Complementary differential scanning calorimetry data indicated the origin of the dimensional instability to be anomalous relaxation at or close to the glass transition. The data are discussed in the context of several proposed valve seat failure mechanisms: contaminant promotion, flow resonance, and now friction. The combined data show significant property variations within the PCTFE resin family. Such property variations could have important implications for the use of PCTFE in valve seat applications. C1 NASA, Lyndon B Johnson Space Ctr, White Sands Test Facil, Honeywell Technol Solut Inc, Las Cruces, NM 88004 USA. RP Waller, JM (reprint author), NASA, Lyndon B Johnson Space Ctr, White Sands Test Facil, Honeywell Technol Solut Inc, POB 20, Las Cruces, NM 88004 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 21 EP 37 DI 10.1520/STP12485S PG 17 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600002 ER PT S AU Waller, JM Haas, JP Beeson, HD AF Waller, JM Haas, JP Beeson, HD BE Steinberg, TA Newton, BE Beeson, HD TI Polymer-oxygen compatibility testing: Effect of oxygen aging on ignition and combustion properties SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE oxygen compatibility; oxygen aging; chloroprene; neoprene; Viton; FKM; silicone rubber; MVQ; Zytel; aliphatic polyamide; nylon; Neoflon; PCTFE; Teflon; PTFE; mechanical properties; TMA; AIT; heat of combustion AB The oxygen (O-2) compatibility of six polymers used in O-2 service was evaluated after 48 h exposures at 121 degreesC (250 degreesF) to O-2 pressures of 620 and 6200 kPa (90 and 900 psia). Three elastomers were tested: chloroprene rubber (C873-70), fluorocarbon rubber (Viton(R)(3) A), and silicone rubber (MVQ type); and three thermoplastics were tested: polyhexamethylene adipamide (Zytel(R)(3) 42), polytetrafluoroethylene (PTFE Teflon(R)(3) 500A), and polychlorotrifluoroethylene (Neoflon(R)(3) CTFE M400H). Post-aged changes in mass, dimensions, tensile strength, elongation at break, durometer hardness, and thermomechanical properties were evaluated. For selected materials, gaseous nitrogen- (GN(2)-) aged controls were used to ascertain the effect of thermal versus oxidative degradation. Finally,. the effect of O-2 aging on selected ignition (AIT) and combustion (DeltaH(c)) properties was determined. As expected, aged polymers were less ignitable and combustible. Special attention was given to Neoflon CTFE; namely, the possible effect of percent crystallinity (quick- versus slow-quenched) on the aging, ignition, and combustion behavior was evaluated. C1 NASA, Lyndon B Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Waller, JM (reprint author), NASA, Lyndon B Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 13 TC 1 Z9 1 U1 1 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 73 EP 86 DI 10.1520/STP12488S PG 14 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600005 ER PT S AU Bryan, CJ Hirsch, DB Haas, J Beeson, HD AF Bryan, CJ Hirsch, DB Haas, J Beeson, HD BE Steinberg, TA Newton, BE Beeson, HD TI Ignitability in air, gaseous oxygen, and oxygen-enriched environments of polymers used in breathing-air devices, final report SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE AB Commercial breathing-air devices contain gases that may vary in concentration from 20.9 percent to 100 percent oxygen at pressures up to 34.5 megapascal (MPa). Analysis of the limited flammability and reactivity data available on some of the materials in these devices under use conditions raised serious concerns about the risks to National Aeronautics and Space Administration (NASA) and contractor personnel at the John F. Kennedy Space Center (KSC). Therefore, these materials were evaluated using the criteria of the ASTM Test Method for Autogenous Ignition Temperature of Liquids and Solids in a High-Pressure Oxygen-Enriched Environment (G 72), ASTM Test Method for Determining Ignition Sensitivity of Materials to Mechanical Impact in Ambient Liquid Oxygen and Pressurized Liquid and Gaseous Oxygen Environments (G 86), ASTM Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (D 240), and Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion (NASA-STD-6001), Test 1, Upward Flame Propagation. Materials typically used in these devices that do not meet the KSC requirements include: polyethylene, (D)elrin(R)(4), Neoprene(R)(4), Buna N(R)(5), Zytel 42(R)(4), ethylene/propylene rubber (EPDM), Tefzel(R)(4), Noryl(R)(6), Buna S(R)(5), and silicone rubber. Comparative data were also generated on Teflon TFE(R)(4), Viton A(R)(4), Vespel SP-21(R)(4), and Kel-F 81(R)(7). In mechanical impact tests, polyethylene, Buna N(R), Neoprene(R), and Zytel 42(R)(4) passed at higher than expected energy levels while Tefzel(R) reacted similar to Delrin(R). In the autoignition tests (AIT), the AIT for Buna N(R), Neoprene(R), ethylene/propylene rubber (EPDM), Buna S(R), Delrin(R) Tefzel(R), Viton A(R), and Zytel 42(R) decreased with increasing oxygen concentrations while the effect of oxygen concentration was minimal for Teflon TFE(R), Kel-F 81(R), Vespel SP-21(R) polyethylene, and silicone, The heats of combustion ranged from 6.17 megajoule per kilogram (MJ/kg) for Kel-F 81(R) to 54.59 MJ/kg for polyethylene. All materials failed the upward flammability test in 20.9 percent oxygen except Teflon TFE(R), silicone, Zytel 42(R), Viton A(R), and Kel-F 81(R). C1 NASA, John F Kennedy Space Ctr, Test Div, Kennedy Space Ctr, FL 32899 USA. RP Bryan, CJ (reprint author), NASA, John F Kennedy Space Ctr, Test Div, Kennedy Space Ctr, FL 32899 USA. NR 5 TC 4 Z9 4 U1 1 U2 5 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 87 EP 100 DI 10.1520/STP12489S PG 14 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600006 ER PT S AU Forsyth, ET Gallus, TD Stoltzfus, JM AF Forsyth, ET Gallus, TD Stoltzfus, JM BE Steinberg, TA Newton, BE Beeson, HD TI Ignition resistance of polymeric materials to particle impact in high-pressure oxygen SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE particle impact; oxygen; flammability; fire; materials; ignition resistance; ignition mechanism; polymers; aluminum particles AB Particle impact ignition has been the primary cause of numerous fires in oxygen systems. This ignition phenomenon is known to occur where particles are present in high-velocity gas and where impact occurs on a flammable material. The particle impact ignition behavior of many metals has been widely studied, but the particle impact ignition behavior of polymeric materials is relatively unknown. Particle impact ignition in polymeric materials is a concern because these materials are commonly used in component seat and seal applications where high-velocity particle impacts can occur. This study evaluates several polymeric materials and compares the threshold temperature, which is the minimum temperature required for ignition, of these materials: Kel-F 81(R) (CTFE), Teflon(R) (TFE), polyetheretherketone (PEEK), and Vespel SP-1(R) (polyimide). The materials were configured as targets in the high-velocity particle impact test system at the NASA White Sands Test Facility. Gaseous oxygen was flowed at 27.5 MPa (4000 psig) and sonic velocity, and the targets were impacted with 2000-mum (0.078-in.) aluminum 2017 particles. This paper discusses the results of these tests and ranks the materials according to their threshold temperatures at these conditions. C1 NASA, Lyndon B Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Forsyth, ET (reprint author), NASA, Lyndon B Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 5 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 101 EP 116 DI 10.1520/STP12490S PG 16 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600007 ER PT S AU Forsyth, ET Durkin, RJ Beeson, HD AF Forsyth, ET Durkin, RJ Beeson, HD BE Steinberg, TA Newton, BE Beeson, HD TI Evaluation of contaminant-promoted ignition in scuba equipment and breathing-gas delivery systems SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE scuba; diving; nitrox; oxygen; flammability; fire; contamination; materials; ignition mechanisms AB As the underwater diving industry continues to use greater concentrations of oxygen in its scuba systems, contaminant ignition becomes of greater concern. In this study, several scuba component assemblies from the Neutral Buoyancy Lab at NASA Johnson Space Center were tested after I year of use. They were pneumatically impacted with 50 percent nitrox gas at 20.7 MPa (3000 psi) to evaluate their ignition resistance then disassembled to assess their cleanliness. A follow-up study was then conducted on the ignition thresholds of hydrocarbon-based oil films in oxygen and nitrox environments to characterize the cleaning requirements for these systems. Stainless steel tubes were contaminated to known levels and tested by pneumatic impact. Ignition was determined with a photocell connected to the end of the contaminated tube. The results of the scuba component tests, cleanliness evaluation, and contaminant ignition study are discussed and compared for 50 percent nitrox and 100 percent oxygen environments. C1 NASA, Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Forsyth, ET (reprint author), NASA, Johnson Space Ctr, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 18 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 357 EP 370 DI 10.1520/STP12505S PG 14 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600022 ER PT S AU Shoffstall, M Stoltzfus, J AF Shoffstall, M Stoltzfus, J BE Steinberg, TA Newton, BE Beeson, HD TI Test system to study the ignition of metals by polymers in oxygen SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE fire hazards; ignition; kindling chain; oxygen; oxygen compatibility AB A new test system that uses laser energy to ignite a polymer promoter has been developed at the NASA White Sands Test Facility (WSTF). It will facilitate the study of kindling chain ignition, such as the spread of fire from a burning polymer material to surrounding metal. The test system can be used to answer questions regarding configurational effects on ignition and combustion. Test results from this system verify that ignition of a metallic sample by kindling chain ignition propagation is dependent not only on pressure, material type, and temperature, but also on the configuration of both the polymer promoter and metallic sample. Both 6061 aluminum and 316 stainless steel rods were tested with Buna-N, silicone, Teflon(R)(3), and Viton(R)(4) O-rings as promoters. The system ignited all four types of O-rings in oxygen at pressures ranging fi om ambient to 69 MPa. However, neither the 316 stainless steel nor the 6061 aluminum rods on which the O-rings were mounted were ignited in any tests. Future testing may be done on the rod and O-ring configuration to evaluate the lack of ignition in these tests. Other configurations may be tested including samples pressurized on one side only and configurations based on fire-damaged components. Any ignition propagation data obtained from this test system could also be used to develop mathematical models for analyzing the effects of configuration on ignition and combustion. C1 NASA, JSC, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Shoffstall, M (reprint author), NASA, JSC, AlliedSignal Tech Serv Corp Team, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 497 EP 509 DI 10.1520/STP12513S PG 13 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600030 ER PT S AU Hirsch, D Bryan, C Barthelemy, H Chou, T Binder, C AF Hirsch, D Bryan, C Barthelemy, H Chou, T Binder, C BE Steinberg, TA Newton, BE Beeson, HD TI An analysis of autoignition temperature round robin test data SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE AB Autoignition temperature (AIT) round robin tests were conducted by seven laboratories on eight polymeric materials. A statistical analysis was conducted that focused on investigating data variability both within and between test methods. With some exceptions, the methods ranked the materials consistently and as expected from their chemical makeup. There was no consistent difference between AIT values determined at 6.9 and 10.3 MPa. BAM and ASTM G72 consistently provided lower, more conservative AITs at both 6.9 and 10.3 MPa. Within an estimated accuracy obtained from all methods from this round robin, data from the following methods appeared to be more accurate than the rest: NF E 29763/88 and Parr Bomb at 6.9 MPa; automated ASTM G72 at 10.3 MPa. The following methods provided lower within-method variability than the average for all methods: BS 3N 100 and ASTM G72 at 6.9 and 10.3 MPa; Parr Bomb at 6.9 MPa. At 6.9 MPa the BAM method provided data with greater within-method variability than the average for all methods. For most materials, the automated ASTM G72 method at 10.3 MPa provided data with greater within-method variability than the average for ail methods. Two data points for this method, Zytel(R)(6) and Teflon(R)(6) FEP, exceeded critical k. At 6.9 MPa, the largest within-method variability resulted from NF E 29763/88 on Zytel, the only data that exceeded critical k. Two extreme results were caused by significant effects of method-specific test parameters: BAM on Zytel at 6.9 MPa and BS 3N 100 on Viton(R)(6) at 10.3 MPa. Statistically these results had a probability of less than 5 percent of occurring by chance. C1 Honeywell Technol Solut Inc, NASA, JSC, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Hirsch, D (reprint author), Honeywell Technol Solut Inc, NASA, JSC, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 510 EP 520 DI 10.1520/STP12514S PG 11 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600031 ER PT S AU Hirsch, D Skarsgard, E Beeson, H Bryan, C AF Hirsch, D Skarsgard, E Beeson, H Bryan, C BE Steinberg, TA Newton, BE Beeson, HD TI Predictability of gaseous impact ignition sensitivity from autoignition temperature data SO FLAMMABILITY AND SENSITIVITY OF MATERIALS IN OXYGEN-ENRICHED ATMOSPHERES: NINTH VOLUME SE AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIAL TECHNICAL PUBLICATION LA English DT Proceedings Paper CT 9th International Symposium on Flammability and Sensitivity of Materials in Oxygen-Enriched Atmospheres CY SEP, 2000 CL PARIS, FRANCE DE ignition sensitivity; autoignition temperature; pneumatic impact; oxygen compatibility; polymers; test methods; Bruceton method AB An analysis of cumulative binomial probabilities for a quantal test like ASTM G 74 indicates that for a probability of reaction in a single trial of 0.05, the probability of obtaining zero reactions in 20 trials is approximately 36 percent. Since the lack of precision of the ASTM G 74 test logic could be potentially misleading, an investigation was conducted to determine if pneumatic impact sensitivity could be predicted more reliably from other, more precise test methods. Pneumatic impact sensitivity testing was conducted following ASTM G 74 but using a rigorous test logic; autoignition temperature (AIT) testing was conducted per ASTM G 72. Polyethylene, polyoxymethylene, polytetrafluoroethylene (PTFE), polyamide, hexafluoropropylene/vinylidene fluoride copolymer, and silicone were the polymers used. After a fixed number of pneumatic impact tests was performed at set pressures, a plot of reaction frequency over a 3.4 to 24.1 MPa impact pressure range indicated that PTFE, hexafluoropropylene/vinylidene fluoride copolymer, and silicone would outperform the other polymers tested. The 50 percent pneumatic impact reactivity level was determined with the Bruceton test method. The data obtained resulted in a strong correlation between the 50 percent reactivity level and the AIT of polymers, indicating similar ignition mechanisms. C1 AlliedSignal Tech Serv Corp, NASA, JSC, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Hirsch, D (reprint author), AlliedSignal Tech Serv Corp, NASA, JSC, White Sands Test Facil, POB 20, Las Cruces, NM 88004 USA. NR 8 TC 4 Z9 4 U1 0 U2 1 PU AMERICAN SOCIETY TESTING AND MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DRIVE, W CONSHOHOCKEN, PA 19428-2959 USA SN 1040-1695 BN 0-8031-2871-1 J9 AM SOC TEST MATER PY 2000 VL 1395 BP 521 EP 528 DI 10.1520/STP12515S PG 8 WC Thermodynamics; Materials Science, Characterization & Testing SC Thermodynamics; Materials Science GA BQ94R UT WOS:000165072600032 ER PT J AU Krishnamurthy, R Woods, DM Chandra, S AF Krishnamurthy, R Woods, DM Chandra, S TI Mixing in hypervelocity flows SO FLOW TURBULENCE AND COMBUSTION LA English DT Article AB This study considers analysis of data obtained from tests with a generic combustor model at the pulse facility T5 located in the Graduate Aeronautical Laboratories at California Institute of Technology (GALCIT). Comparisons were made between the flow predictions using Baldwin-Lomas and k-epsilon turbulence models. Computed predictions of mixing efficiency, wall pressure signatures, eddy viscosity distributions, etc., obtained from both the turbulence models were similar. Computed wall pressure distributions agreed with those from experiments. Spatial uniformity of the injectant-test gas mixture was considered. Based on the results obtained, use of the Baldwin-Lomax turbulence model can be considered to be sufficient for the conditions considered, as it yields adequate predictions with significant savings in computational costs. C1 N Carolina Agr & Technol State Univ, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. RP Krishnamurthy, R (reprint author), N Carolina Agr & Technol State Univ, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. NR 8 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 1386-6184 J9 FLOW TURBUL COMBUST JI Flow Turbul. Combust. PY 2000 VL 64 IS 1 BP 29 EP 41 DI 10.1023/A:1009978503749 PG 13 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 350VK UT WOS:000089121700002 ER PT J AU Sellers, CC Walker, JS Szofran, FR Motakef, S AF Sellers, CC Walker, JS Szofran, FR Motakef, S TI Melt motion due to peltier marking during Bridgman crystal growth with an axial magnetic field SO FLOW TURBULENCE AND COMBUSTION LA English DT Article DE magnetohydrodynamics; crystal growth; Peltier marking; magnetic damping AB This paper treats a liquid-metal flow inside an electrically insulating cylinder with electrically conducting solids above and below the liquid region. There is a uniform axial magnetic field, and there is an electric current through the liquid and both solids. Since the lower liquid-solid interface is concave into the solid and since the liquid is a better electrical conductor than the adjacent solid, the electric current is locally concentrated near the centerline. The return to a uniform current distribution involves a radial electric current which interacts with the axial magnetic field to drive an azimuthal flow. The axial variation of the centrifugal force due to the azimuthal velocity drives a meridional circulation with radial and axial velocities. This problem models the effects of Peltier marking during the vertical Bridgman growth of semiconductor crystals with an externally applied magnetic field, where the meridional circulation due to the Peltier current may produce important mixing in the molten semiconductor. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Cape Simulat Inc, Newton, MA 02158 USA. RP Sellers, CC (reprint author), Univ Illinois, Dept Mech & Ind Engn, 140 Mech Engrg Bldg,MC-244,1206 W Green St, Urbana, IL 61801 USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1386-6184 EI 1573-1987 J9 FLOW TURBUL COMBUST JI Flow Turbul. Combust. PY 2000 VL 64 IS 3 BP 197 EP 214 DI 10.1023/A:1009980601722 PG 18 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 375BE UT WOS:000165379000004 ER PT J AU Thacker, WD Grosch, CE Gatski, TB AF Thacker, WD Grosch, CE Gatski, TB TI Modeling the dynamics of ensemble-averaged linear disturbances in homogeneous shear flow SO FLOW TURBULENCE AND COMBUSTION LA English DT Article DE transition/turbulence modeling; homogeneous shear; rapid distortion theory ID TURBULENT-FLOW; GRADIENT; FIELD AB In order to expand the predictive capability of single-point turbulence closure models to account for the early-stage transition regime, a methodology for the formulation and calibration of model equations for the ensemble-averaged disturbance kinetic energy and energy dissipation rate is presented. The calibration is based on homogeneous shear flow where disturbances can be described by rapid distortion theory (RDT). The relationship between RDT and linear stability theory is exploited in order to obtain a closed set of modeled equations. The linear disturbance equations are solved directly so that the numerical simulation yields a database from which the closure coefficients in the ensemble-averaged disturbance equations can be determined. C1 St Louis Univ, Parks Coll, Dept Phys, St Louis, MO 63156 USA. Old Dominion Univ, Dept Oceanog, Norfolk, VA 23529 USA. Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Thacker, WD (reprint author), St Louis Univ, Parks Coll, Dept Phys, St Louis, MO 63156 USA. NR 19 TC 0 Z9 0 U1 0 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1386-6184 EI 1573-1987 J9 FLOW TURBUL COMBUST JI Flow Turbul. Combust. PY 2000 VL 63 IS 1-4 BP 39 EP 58 DI 10.1023/A:1009969805726 PG 20 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 350VJ UT WOS:000089121600004 ER PT J AU So, RMC Zhao, CY Gatski, TB AF So, RMC Zhao, CY Gatski, TB TI Predicting buoyant shear flows using anisotropic dissipation rate models SO FLOW TURBULENCE AND COMBUSTION LA English DT Article DE buoyant flow modeling; anisotropic dissipation; turbulence modeling ID GRID-GENERATED TURBULENCE; REYNOLDS STRESS CLOSURES; HOMOGENEOUS TURBULENCE; CHANNEL FLOW; STRATIFIED FLUID; EVOLUTION; STATES; NUMBER AB This paper examines the modeling of two-dimensional homogeneous stratified turbulent shear flows using the Reynolds-stress and Reynolds-heat-flux equations. Several closure models have been investigated; the emphasis is placed on assessing the effect of modeling the dissipation rate tensor in the Reynolds-stress equation. Three different approaches are considered; one is an isotropic approach while the other two are anisotropic approaches. The isotropic approach is based on Kolmogorov's hypothesis and a dissipation rate equation modified to account for vortex stretching. One of the anisotropic approaches is based on an algebraic representation of the dissipation rate tensor, while another relies on solving a modeled transport equation for this tensor. In addition, within the former anisotropic approach, two different algebraic respresentations are examined; one is a function of the Reynolds-stress anisotropy tensor, and the other is a function of the mean velocity gradients. The performance of these closure models is evaluated against experimental and direct numerical simulation data of pure shear flows, pure buoyant flows and buoyant shear flows. Calculations have been carried out over a range of Richardson numbers (Ri) and two different Prandtl numbers (Pr); thus the effect of Pr on the development of counter-gradient heat flux in a stratified shear flow can be assessed. At low Ri, the isotropic model performs well in the predictions of stratified shear flows; however, its performance deteriorates as Ri increases. At high Ri, the transport equation model for the dissipation rate tensor gives the best result. Furthermore, the results also lend credence to the algebraic dissipation rate model based on the Reynolds stress anisotropy tensor. Finally, it is found that Pr has an effect on the development of counter-gradient heat flux. The calculations show that, under the action of shear, counter-gradient heat flux does not occur even at Ri = 1 in an air flow. C1 Hong Kong Polytech Univ, Dept Mech Engn, Kowloon, Hong Kong, Peoples R China. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP So, RMC (reprint author), Hong Kong Polytech Univ, Dept Mech Engn, Hung Hom, Kowloon, Hong Kong, Peoples R China. NR 36 TC 1 Z9 1 U1 1 U2 3 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1386-6184 EI 1573-1987 J9 FLOW TURBUL COMBUST JI Flow Turbul. Combust. PY 2000 VL 63 IS 1-4 BP 193 EP 221 DI 10.1023/A:1009996522874 PG 29 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA 350VJ UT WOS:000089121600011 ER PT B AU Liu, WT Tang, WQ Datta, A Hsu, CS AF Liu, WT Tang, WQ Datta, A Hsu, CS GP AMS AMS TI Monitoring marine weather systems using QuikSCAT and TRMM data SO FOURTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 4th Symposium on Integrated Observing Systems CY JAN 09-14, 2000 CL LONG BEACH, CA SP Amer Meteorol Soc ID SCATTEROMETER C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, WT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2000 BP 94 EP 97 PG 4 WC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing SC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing GA BS02X UT WOS:000168377700021 ER PT B AU Todling, R Dee, DP AF Todling, R Dee, DP GP AMS AMS TI Estimation of analysis error covariances from observation residuals SO FOURTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 4th Symposium on Integrated Observing Systems CY JAN 09-14, 2000 CL LONG BEACH, CA SP Amer Meteorol Soc ID ATMOSPHERIC DATA ASSIMILATION; MAXIMUM-LIKELIHOOD-ESTIMATION; ANALYSIS SYSTEM; FORECAST; PERFORMANCE; PARAMETERS C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Todling, R (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2000 BP 108 EP 113 PG 6 WC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing SC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing GA BS02X UT WOS:000168377700026 ER PT B AU Atlas, R Brin, E Bloom, SC Ardizzone, J Terry, J Jusem, JC Bungato, D AF Atlas, R Brin, E Bloom, SC Ardizzone, J Terry, J Jusem, JC Bungato, D GP AMS AMS TI Assimilation of SeaWinds scatterometer data in the GEOS data assimilation system SO FOURTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 4th Symposium on Integrated Observing Systems CY JAN 09-14, 2000 CL LONG BEACH, CA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Atlas, R (reprint author), NASA, Goddard Space Flight Ctr, Code 910-3, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2000 BP 114 EP 118 PG 5 WC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing SC Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing GA BS02X UT WOS:000168377700027 ER PT S AU Hamkins, J Ceniceros, J AF Hamkins, J Ceniceros, J BE Mecherle, GS TI The capacity of avalanche photodiode-detected pulse position modulation SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XII CY JAN 24, 2000 CL SAN JOSE, CA SP SPIE DE capacity; pulse position modulation; avalanche photodiode detector; Reed-Solomon; Webb statistics ID PHOTON AB The capacity is determined for an optical channel employing Pulse Position Modulation (PPM) and an Avalanche PhotoDiode (APD) detector. This channel is different from the usual optical channel in that the detector output is characterized by a Webb-plus-Gaussian distribution, not a Poisson distribution. The capacity is expressed as a function of the PPM order, slot width, laser dead time, average number of incident signal and background photons received, and APD parameters. Based on a system using a laser and detector proposed for X2000 second delivery, numerical results provide upper bounds on the data rate and level of background noise that the channel can support while operating at a given BER. For the particular case studied, the capacity-maximizing PPM order is near 2048 for nighttime reception and 16 for daytime reception. Reed-Solomon codes can handle background levels 2.3 to 7.6 dB below the ultimate level that can be handled by codes operating at the Shannon limit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 2 Z9 2 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3549-X J9 P SOC PHOTO-OPT INS PY 2000 VL 3932 BP 90 EP 101 DI 10.1117/12.384321 PG 12 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BQ31S UT WOS:000087916800010 ER PT S AU Wilson, KE Britcliffe, M Golshan, N AF Wilson, KE Britcliffe, M Golshan, N BE Mecherle, GS TI Progress in design and construction of the optical communications telescope laboratory (OCTL) SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XII CY JAN 24, 2000 CL SAN JOSE, CA SP SPIE DE free space optical communications; lasercom; telescopes; ground stations; adaptive optics; astrometry; Table Mountain Facility AB JPL is constructing an Optical Communications Telescope Laboratory (OCTL) at its Table Mountain Facility complex in the San Bernadino Mountains of Southern California. The OCTL will house a l-m class telescope and serve as an R&D ground station supporting future optical communications demonstrations with Earth-orbiting satellites and deep space probes. It will also support research in adaptive optics, optical receiver technologies, and help in developing spacecraft acquisition and tracking strategies from future optical ground stations. The OCTL building was completed in November 1999, and Brashear-LP of Pittsburgh, PA has been selected to build the telescope. First light is expected in July 2001. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilson, KE (reprint author), Jet Prop Lab, MS 161-135,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3549-X J9 P SOC PHOTO-OPT INS PY 2000 VL 3932 BP 112 EP 116 DI 10.1117/12.384302 PG 5 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BQ31S UT WOS:000087916800012 ER PT S AU Ortiz, GG Sandusky, JV Biswas, A AF Ortiz, GG Sandusky, JV Biswas, A BE Mecherle, GS TI Design of the opto-electronic receiver for deep space optical communications SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XII CY JAN 24, 2000 CL SAN JOSE, CA SP SPIE DE opto-electronic receiver; free-space communications; deep space optical communications; background noise power; APD AB The opto-electronic receiver (detector and pre-amplifier) necessary to meet the demands of high capacity deep space missions is designed for a Mars-Earth optical communication link. The receiver requirements are driven by link performance (data rate, bit-error rate, margin), delivered power, pulse width, background signal, telescope quality, and atmospheric effects. Meeting these requirements becomes more challenging as the mission range and the demand for link capacity increases. In this article, the detector's characteristics (e.g. quantum efficiency, noise, gain, and diameter) are designed to address these various requirements. The receiver sensitivity's dependence on the background noise power and on the APD detector's characteristics is analyzed. The improvement in opto-electronic receiver sensitivity is quantified for improvements in APD quantum efficiency, ionization factor, and hulk dark current. It is also found that as the background signal increases the improvement on the receiver sensitivity from an improved detector is diminished due to the quantum noise limit. An opto-electronic receiver is designed based on a Silicon APD to meet the mission requirement of a PPM (M=256) 30 kbps data rate (BER of 10(-5)) link. Improvements to the APD detector are also studied to describe a design that would achieve over 50 kbps data rates for a Mars-Earth optical communication link. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ortiz, GG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 161-135, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3549-X J9 P SOC PHOTO-OPT INS PY 2000 VL 3932 BP 127 EP 138 DI 10.1117/12.384304 PG 12 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BQ31S UT WOS:000087916800014 ER PT S AU Lee, S Alexander, JW Jeganathan, M AF Lee, S Alexander, JW Jeganathan, M BE Mecherle, GS TI Pointing and tracking subsystem design for optical communications link between the international space station and ground SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XII CY JAN 24, 2000 CL SAN JOSE, CA SP SPIE DE free-space optical communication; tracking and pointing; International Space Station AB We present a preliminary design for a tracking and pointing subsystem for the optical communication link between the International Space Station (ISS) and a ground receiver at Table Mountain Facility. The link is intended to demonstrate high rate downlink capability of rates up to 2.5Gbps. The design objective of tracking and pointing subsystem is to limit the pointing loss to within 4dB to ensure the maximum downlink capability with 3dB link margin. We will show the underlying tracking and pointing subsystem design and present analysis that shows the allocated error budget can be met. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 19 Z9 21 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3549-X J9 P SOC PHOTO-OPT INS PY 2000 VL 3932 BP 150 EP 157 DI 10.1117/12.384306 PG 8 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BQ31S UT WOS:000087916800016 ER PT S AU Hemmati, H Wright, M Biswas, A Esproles, C AF Hemmati, H Wright, M Biswas, A Esproles, C BE Mecherle, GS TI High-efficiency pulsed laser transmitters for deep-space communication SO FREE-SPACE LASER COMMUNICATION TECHNOLOGIES XII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Free-Space Laser Communication Technologies XII CY JAN 24, 2000 CL SAN JOSE, CA SP SPIE DE optical communications; laser; high efficiency ID SWITCHED FIBER LASER; ERBIUM-DOPED FIBER; THEORETICAL-ANALYSIS; OPTICAL-FIBER; DIODE; AMPLIFIERS; OUTPUT; CW; NM AB Highly efficient laser sources are required for deep space optical telecommunication. This paper investigates the efficiency components for pulsed diode pumped solid state laser transmitters and determines the overall wall-plug efficiency applicable to a space-borne system. Thermal control of the pump diodes is critical to achieving optimum photon efficiency. Hence, a thermal model involving either a thermo-electric cooler or loop heat pipes is applied to the efficiency calculations. The electro-optical conversion efficiency for an optimized bulk design is expected to be up to 28 % with the overall wail-plug efficiency being in the 12-16 % range depending on the radiator temperature. A fiber based master-oscillator power-amplifier design is also investigated with passively cooled pumped diodes and promises high efficiency operation. Preliminary results from an evaluation model are also discussed. C1 CALTECH, Jet Prop Lab, Opt Commun Grp, Pasadena, CA 91109 USA. RP Hemmati, H (reprint author), CALTECH, Jet Prop Lab, Opt Commun Grp, 4800 Oak Grove Dr,M-S 161-135, Pasadena, CA 91109 USA. NR 22 TC 11 Z9 11 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3549-X J9 P SOC PHOTO-OPT INS PY 2000 VL 3932 BP 188 EP 195 DI 10.1117/12.384309 PG 8 WC Engineering, Aerospace; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA BQ31S UT WOS:000087916800020 ER PT S AU Prestage, JD Tjoelker, RL Maleki, L AF Prestage, JD Tjoelker, RL Maleki, L BE Luiten, AN TI Recent developments in microwave ion clocks SO FREQUENCY MEASUREMENT AND CONTROL ADVANCED TECHNIQUES AND FUTURE TRENDS SE Topics in Applied Physics LA English DT Review ID LASER-COOLED IONS; FREQUENCY STANDARD; TRAPPED-ION; CHAOS; ORDER AB We review the development of microwave-frequency standards: based on trapped ions. Following two distinct paths, microwave ion clocks have evolved greatly in the last twenty years since the earliest Paul-trap-based units. Laser-cooled ion frequency standards reduce the second-order Doppler shift from ion micromotion and thermal secular motion achieving good signal-to-noise ratios via cycling transitions where as many as approximate to 10(8) photons per second per ion may be scattered. Today, laser-cooled ion standards are based on linear Paul traps which hold lolls near the node line of the trapping electric field, minimixing micromotion at the trapping-field frequency and the consequent second-order Doppler frequency shift. These quadrupole (radial) field traps tightly confine tens of ions to a crystalline single-line structure. As more ions are trapped, space charge forces some ions away from the node-line axis and the second-order Doppler effect grows larger, even at negligibly small secular temperatures. Buffer-gas-cooled clocks rely on large numbers of ions, typically approximate to 10(7), optically pumped by a discharge lamp at a scattering rate of a few photons per second per ion. To reduce the second-order Doppler shift from space charge repulsion of lolls from the trap node line, novel multipole ion traps are now being developed where lolls are weakly bound with confining fields that are effectively zero through the trap interior and grow rapidly near the trap electrode "walls''. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91104 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Bldg 298, Pasadena, CA 91104 USA. EM John.D.Prestage@jpl.nasa.gov RI Luiten, Andre/G-5737-2011 OI Luiten, Andre/0000-0001-5284-7244 NR 23 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0303-4216 BN 3-540-67694-5 J9 TOP APPL PHYS JI Top. Appl. Phys. PY 2000 VL 79 BP 195 EP 211 PG 17 WC Physics, Applied SC Physics GA BS45D UT WOS:000169892300007 ER PT B AU Lissauer, JJ Lin, DNC AF Lissauer, JJ Lin, DNC BE Bergeron, J Renzini, A TI Diversity of planetary systems: Formation scenarios and unsolved problems SO FROM EXTRASOLAR PLANETS TO COSMOLOGY: THE VLT OPENING SYMPOSIUM SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT VTL Opening Symposium CY MAR 01-04, 1999 CL ANTOFAGASTA, CHILE SP Univ Catolica Norte ID ORION-NEBULA-CLUSTER; SOLAR-TYPE STAR; GIANT PLANETS; CIRCUMSTELLAR DISKS; TIDAL INTERACTION; NUMERICAL SIMULATIONS; PROTOPLANETARY DISKS; ORBITAL MIGRATION; ACCRETION DISKS; RUNAWAY GROWTH AB Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may be depleted before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth may decay rapidly and sweep up smaller planets in their path. The potential of the VLT to improve our understanding of planetary formation is discussed briefly. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. EM lissauer@ringside.arc.nasa.gov; lin@ucolick.org NR 73 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67163-3 J9 ESO ASTROPHY SYMP PY 2000 BP 377 EP 390 DI 10.1007/10720961_56 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39H UT WOS:000088231200056 ER PT B AU van Belle, GT AF van Belle, GT BE Bergeron, J Renzini, A TI From PTI to the Keck Interferometer SO FROM EXTRASOLAR PLANETS TO COSMOLOGY: THE VLT OPENING SYMPOSIUM SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT VTL Opening Symposium CY MAR 01-04, 1999 CL ANTOFAGASTA, CHILE SP Univ Catolica Norte ID PALOMAR TESTBED INTERFEROMETER; EFFECTIVE TEMPERATURES; ANGULAR DIAMETERS; K-GIANT; SUPERGIANTS; RADII AB The Keck Interferometer project will link together the Keek 1 and Keek 2 telescopes as a single instrument, building the technical and scientific achievements of the Palomar Testbed Interferometer (PTI). Specifics of PTI research and the Keek design are presented herein. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP van Belle, GT (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67163-3 J9 ESO ASTROPHY SYMP PY 2000 BP 450 EP 461 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39H UT WOS:000088231200065 ER PT B AU Unwin, S AF Unwin, S BE Bergeron, J Renzini, A TI Searching for planets with the space interferometry mission SO FROM EXTRASOLAR PLANETS TO COSMOLOGY: THE VLT OPENING SYMPOSIUM SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT VTL Opening Symposium CY MAR 01-04, 1999 CL ANTOFAGASTA, CHILE SP Univ Catolica Norte ID COMPANION AB The Space Interferometry Mission (SIM) will be the first space-based long baseline Michelson interferometer designed for precision astrometry. It will address a wide range of problems in stellar astrophysics and Galactic structure, delivering precision astrometry of stars down to 20 magnitude throughout the entire Galaxy. SIM uses a 10-m Michelson interferometer in Earth-trailing solar orbit to provide 4 microarcsecond (mu as) precision astrometry. With a 5-year mission lifetime, SIM will be a powerful tool for discovering planets around nearly stars, through detection of the stellar reflex motion. The astrometric method complements the radial velocity technique which as already yielded many new planets, with an important benefit of directly measuring planetary masses. SIM will have a single-measurement precision of 1 mu as in a frame defined by nearly reference stars, enabling searches for planets with masses as small as a few earth masses around the nearest stars. More massive planets will be detectable to much larger distances. In addition to precision astrometry SIM will also serve an important role as a technology precursor for future astrophysics missions using interferometers. Two technologies demonstrated will be high dynamic-range aperture synthesis imaging at 10-milliarcsec resolution in the optical, and fringe nulling to 10(-4). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Unwin, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67163-3 J9 ESO ASTROPHY SYMP PY 2000 BP 492 EP 498 DI 10.1007/10720961_70 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39H UT WOS:000088231200070 ER PT B AU Queloz, D Mayor, M Naef, D Santos, N Udry, S Burnet, M Confino, B AF Queloz, D Mayor, M Naef, D Santos, N Udry, S Burnet, M Confino, B BE Bergeron, J Renzini, A TI Extrasolar planets in the southern hemisphere: The CORALIE survey SO FROM EXTRASOLAR PLANETS TO COSMOLOGY: THE VLT OPENING SYMPOSIUM SE ESO ASTROPHYSICS SYMPOSIA LA English DT Proceedings Paper CT VTL Opening Symposium CY MAR 01-04, 1999 CL ANTOFAGASTA, CHILE SP Univ Catolica Norte ID GIANT PLANETS; PARENT STARS; EVOLUTION; ECCENTRICITY; SYSTEMS AB We are conducting a large survey to detect extrasolar planets by high precision Doppler spectroscopy using the new swiss Euler telescope and the spectrograph CORALIE. The sample includes 1600 nearby G and K stars from the southern hemisphere. The simultaneous thorium technique is used to reach very high precision radial velocity measurements. Less than 6 months after the setup of the instrument two planetary candidates have been detected, almost 20 planetary candidates have been discovered by various high precision Doppler spectroscopy surveys. The semi-major axis of the planetary candidate orbits ranges from very small (0.05 AU) to 3 AU. Some have eccentric orbits, others have a more massive secondary companion, some have both. This large spread in orbital characteristics is difficult to fit into a single formation scenario. Current results also suggest a planet maximum mass around 7-9 M-J. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Queloz, D (reprint author), CALTECH, Jet Prop Lab, Mail Stop 306-388,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 7 Z9 8 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-67163-3 J9 ESO ASTROPHY SYMP PY 2000 BP 548 EP 555 DI 10.1007/10720961_79 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39H UT WOS:000088231200079 ER PT B AU West, RA AF West, RA BE Griffith, CA Marley, MS TI Condensates in jovian atmospheres SO FROM GIANT PLANETS TO COOL STARS, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on From Giant Planets to Cool Stars CY JUN 08-11, 1999 CL NORTHERN ARIZONA UNIV, FLAGSTAFF, AZ SP NASA Planetary Atmospheres Program HO NORTHERN ARIZONA UNIV ID CLOUD MICROPHYSICS; PLANETS; ABSORPTION; NEPTUNE; METHANE AB Thermochemical equilibrium theory which starts with temperature/pressure profiles, compositional information and thermodynamic data for condensable species in the jovian planet atmospheres predicts layers of condensate clouds in the upper troposphere. The deepest of these is a water/ammonia solution near the 6-bar pressure level for Jupiter, At higher altitudes H(2)S and NH(3) react to form NH(4)SH which is predicted to condense in Jupiter's atmosphere near 2 bars pressure. At higher levels NH(3) or H(2)S will condense, depending on which of these is depleted first during formation of the NH4SH cloud. Observations indicate that ammonia forms the upper cloud in the atmospheres of Jupiter and Saturn while hydrogen sulfide forms this cloud in the atmospheres of Uranus and Neptune. Methane ice clouds are present at higher altitudes in the atmospheres of Uranus and Neptune. An abundance of remote and (for Jupiter) in situ observations provide information on particle optical depths and sizes, at least for the uppermost cloud layer. In spite of all this information good microphysical models for cloud particle size distribution and optical depth remain elusive because they require detailed knowledge of atmospheric dynamics and cloud microphysics much beyond what is now possible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP West, RA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 1 Z9 1 U1 1 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-041-2 J9 ASTR SOC P PY 2000 VL 212 BP 106 EP 113 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR85Y UT WOS:000167828400014 ER PT B AU Freedman, RS AF Freedman, RS BE Griffith, CA Marley, MS TI The development of opacity databases for brown dwarfs and extra solar giant planets SO FROM GIANT PLANETS TO COOL STARS, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on From Giant Planets to Cool Stars CY JUN 08-11, 1999 CL NORTHERN ARIZONA UNIV, FLAGSTAFF, AZ SP NASA Planetary Atmospheres Program HO NORTHERN ARIZONA UNIV ID DATA-BANK; VO; SPECTROSCOPY; SYSTEM; STATE; WATER AB The accurate modeling of the atmospheric opacity of brown dwarfs and extra solar giant planets (ESP) requires atomic and molecular opacities that cover a wide range of physical parameters, and frequently involves species that, for a variety of reasons, have not been well studied, either in the laboratory or theoretically. Even when good laboratory data is available, information on lines that originate from excited levels, only populated at high temperatures, is frequently missing from the tabulation. This results in missing opacity from the 'hot' bands of molecules. Other problems with laboratory data include the inability to analyze bands that are not resolved on a line by line basis (many of the bands of CH4 fall into this category), or the difficulty in conducting laboratory experiments and measurements on highly reactive species. This implies that molecular opacity generated using only data derived from laboratory studies may be incomplete and will underestimate the true opacity, especially at higher temperatures. C1 NASA, Ames Res Ctr, Space Phys Res Inst, Moffett Field, CA 94035 USA. RP Freedman, RS (reprint author), NASA, Ames Res Ctr, Space Phys Res Inst, MS 245-3, Moffett Field, CA 94035 USA. NR 20 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 1-58381-041-2 J9 ASTR SOC P PY 2000 VL 212 BP 181 EP 186 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR85Y UT WOS:000167828400021 ER PT B AU Deming, D Wiedemann, G Bjoraker, G AF Deming, D Wiedemann, G Bjoraker, G BE Griffith, CA Marley, MS TI Prospects for direct spectral detection and characterization of "hot Jupiters" SO FROM GIANT PLANETS TO COOL STARS, PROCEEDINGS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Workshop on From Giant Planets to Cool Stars CY JUN 08-11, 1999 CL NORTHERN ARIZONA UNIV, FLAGSTAFF, AZ SP NASA Planetary Atmospheres Program HO NORTHERN ARIZONA UNIV ID COMPANION; 51-PEGASI; PLANET AB We have obtained a large quantity of infrared spectroscopic data for 51 Peg, Ups And, and Tau Boo, primarily in the 3.3 mum methane band, but also in the 2.3 and 4.6 mum bands of CO. The observations used the CSHELL spectrometer on the NASA IRTF, and the Phoenix spectrometer on the Kitt Peak 4-meter telescope. We have developed a cross-correlation technique to search for the presence of methane and CO features due to the planetary companions. We describe the concept and execution of the cross-correlation analysis, and show preliminary results for 3.3 mum methane in 51 Peg. The expected planetary features are about one order of magnitude weaker than our current sensitivity. Future improvements in the data acquisition and analysis should bring the planetary signatures within the range of this method. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Code 693, Greenbelt, MD 20771 USA. RI Bjoraker, Gordon/D-5032-2012 NR 10 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 1-58381-041-2 J9 ASTR SOC P PY 2000 VL 212 BP 308 EP 314 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR85Y UT WOS:000167828400035 ER PT B AU Sahai, R Trauger, J Stapelfeldt, K Moody, D Lunine, J AF Sahai, R Trauger, J Stapelfeldt, K Moody, D Lunine, J BE Griffith, CA Marley, MS TI Detection and characterization of nearby giant planet and brown dwarf companions with an NGST coronagraph SO FROM GIANT PLANETS TO COOL STARS, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on From Giant Planets to Cool Stars CY JUN 08-11, 1999 CL NORTHERN ARIZONA UNIV, FLAGSTAFF, AZ SP NASA Planetary Atmospheres Program HO NORTHERN ARIZONA UNIV ID GLIESE 229B; DISCOVERY; SPECTRA AB We describe a study of giant planet and brown dwarf companions to single stars within 20 parsecs of the Sun, as part of the NGST Design Reference Mission. These substellar objects can be directly detected from their high emission in the lambda = 4.6-5.1 mum molecular opacity window through the use of a coronagraph and the nominal NGST wavefront. Combining the emergent fluxes from recent giant planet/brown dwarf atmosphere models, stellar data from the Gliese catalog, and a detailed model of coronagraph performance for the case of a seven segment primary mirror, we find that NGST will be capable of imaging planetary companions of Jupiter's mass, age, and orbital semi-major axis around all single stars within 8 pc of the Sun in integration times of three hours or less. Our proposed program of coronagraphic observations will carry out (1) a survey of the nearest 180 single stars for Jupiter-like companions complete to 8 pc, (2) a survey of the nearest 500 single stars for more luminous (i.e. younger or more massive) companions complete to a 5 mum flux level 40 times that of Jupiter, and (3) detailed spectrophotometric study of selected objects discovered in these two surveys. These observations can be expected to provide results of fundamental importance to our understanding of planetary systems and their frequency in the galaxy: (1) the first determination of the giant planet/brown dwarf luminosity function, (2) the first spectral characterization of these objects across a broad range of effective temperatures, and (3) the first direct images of planets orbiting another star. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sahai, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS183-900, Pasadena, CA 91109 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 17 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 1-58381-041-2 J9 ASTR SOC P PY 2000 VL 212 BP 338 EP 346 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR85Y UT WOS:000167828400039 ER PT S AU Israelsson, UE Lee, MC AF Israelsson, UE Lee, MC BE Vitale, S TI The NASA microgravity fundamental physics program SO FUNDAMENTAL PHYSICS IN SPACE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT HO 1 Symposium of COSPAR Scientific Commission H Held at the 32nd COSPAR Scientific Assembly CY JUL 12-19, 1998 CL NAGOYA, JAPAN SP European Space Agcy, Comm Space Res AB Gravity obscures some of the most subtle phenomena that are key to solving outstanding questions in physics today. To address these questions, the micro-gravity research division of NASA has recently formed a fundamental physics discipline. Currently, the research focus areas in this discipline are Low Temperature and Condensed Matter Physics (LT/CMP), Laser Cooling and Atomic Physics (LCAP) and Gravitational and Relativistic Physics (GRP). NASA objectives in these areas are to support ground-based research with flight potential, to develop research-enabling technologies and to conduct flight investigations. There are currently 54 on-going research investigations being funded, 8 of which are potential flight experiments. A review of the current directions of research in this discipline will be presented. NASA's plans for development of flight hardware to support research on the International Space Station over the next decades will also be discussed including the planned development of a cryogenic facility for providing an environment below 2 Kelvin for up to 6 months to future investigators. (C) 2000 COSPAR. Published by Elsevier Science Ltd. C1 Jet Propuls Lab, Pasadena, CA 91109 USA. NASA Headquarters, Code UG, Washington, DC 20546 USA. RP Israelsson, UE (reprint author), Jet Propuls Lab, MS 233-200,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2000 VL 25 IS 6 BP 1125 EP 1128 DI 10.1016/S0273-1177(99)00972-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BP57V UT WOS:000085558300002 ER PT S AU Wadsworth, M Elliott, T Atlas, G AF Wadsworth, M Elliott, T Atlas, G BE Denton, MB TI Advances in scientific-quality detectors at JPL: Hybrid Imaging Technology SO FURTHER DEVELOPMENTS IN SCIENTIFIC OPTICAL IMAGING SE ROYAL SOCIETY OF CHEMISTRY SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 4th International Conference on Scientific Optical Imaging CY DEC 02-05, 1998 CL GEORGETOWN, W IND ASSOC ST AB Recently work was begun at JPL to create a next-generation imager technology, called Hybrid Imaging Technology (HIT), that offers scientific-quality imaging performance. The key principle of this technique is the merging of CCD and CMOS technologies by device hybridization rather than by process integration. HIT offers the exceptional quantum efficiency, fill factor, broad spectral response, and very low noise properties of CCD imagers with the low-power operation and flexibility of integration found in CMOS devices. In this work we present the architecture, benefits, performance, and future directions of HIT. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wadsworth, M (reprint author), CALTECH, Jet Prop Lab, Mail Stop 300-315,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, CAMBRIDGE CB4 4WF, CAMBS, ENGLAND SN 0260-6291 BN 0-85404-784-0 J9 ROY SOC CH PY 2000 IS 254 BP 24 EP 30 DI 10.1039/9781847550958-00024 PG 3 WC Optics SC Optics GA BQ79Q UT WOS:000089544800005 ER PT S AU Meegan, C Hakkila, J Johnson, A Pendleton, G Mallozzi, R AF Meegan, C Hakkila, J Johnson, A Pendleton, G Mallozzi, R BE Kippen, RM Mallozzi, RS Fishman, GJ TI A summary of biases in the BATSE burst trigger SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn AB Interpreting the BATSE burst intensity distribution requires an understanding of the biases introduced by the on-board trigger algorithm. We present a classification and description of these biases. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Meegan, C (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 6 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 43 EP 47 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400009 ER PT S AU Norris, JP Marani, GF Bonnell, JT AF Norris, JP Marani, GF Bonnell, JT BE Kippen, RM Mallozzi, RS Fishman, GJ TI Connection between spectral lags and peak luminosity in GRBs SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID GAMMA-RAY BURSTS AB For the set of six gamma-rag bursts with redshifts observed by BeppoSAX and CGRO/BATSE, their isotropic peak luminosities and spectral lags are anti-correlated. In this small set of bursts, the relationship is approximated by a pomes-law, L-53 approximate to 1.3 x (tau /0.01 S)(-1.15). While GRB 980425 (if associated with SN 1998bw) would appear to extend this trend qualitatively, it falls below the power-law relationship by a factor of several hundred. The same underlying anti-correlation, but apparently convolved with redshift, appears to be manifest in the 30% brightest BATSE: bursts - dimmer bursts tend to have longer spectral lags. These results appear to lend at least empirical meaning to the GRB pulse paradigm: short spectral lag and therefore narrow pulse width are somehow related to high luminosity. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Norris, JP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 78 EP 82 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400016 ER PT S AU Bonnell, JT Norris, JP Marani, GF Nemiroff, RJ AF Bonnell, JT Norris, JP Marani, GF Nemiroff, RJ BE Kippen, RM Mallozzi, RS Fishman, GJ TI GRB time-dilation measurements corrected for trigger bias SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID GAMMA-RAY BURSTS AB We measure time-dilation factors (TDFs) for 1155 Long gamma-rag bursts (GRBs) using a peak-alignment method. Our standard corrections for noise bias and spectral redshift are implemented. Also for the first time we account for trigger bias against detecting relatively short, low signal-to-noise GRBs using a retriggering procedure which approximates the on-board BATSE algorithm on the 1024-ms timescale. This procedure implicitly addresses any bias that would be introduced when comparing bright bursts with dim bursts. The retriggering step significantly reduces the relative TDFs between the 10% brightest bursts and the 30% dimmest bursts. These corrected TDFs are compared with Monte Carlo simulations of a distribution of GRBs adopting standard cosmologies, GRB luminosity functions, and GRB rate-density evolution with cosmic time. Statistically, the corrected GRB TDFs are consistent with the expected extrinsic cosmological time dilation. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bonnell, JT (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 210 EP 214 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400041 ER PT S AU Connaughton, V AF Connaughton, V BE Kippen, RM Mallozzi, RS Fishman, GJ TI BATSE observations of gamma-ray burst tails SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID 28 FEBRUARY 1997; AFTERGLOW AB With the discovery of low-energy radiation appearing to come from the site of gamma-ray bursts in the hours to weeks after the initial burst of gamma rays, it would appear that astronomers have finally seen a cosmological imprint made by the burster on its surroundings. I discuss in this paper the phenomenon of post-burst emission in BATSE gamma-ray bursts at energies traditionally associated with prompt emission. By summing the background-subtracted signals from hundreds of BATSE bursts, I find that tails out to 2000 seconds after the trigger may be a common feature of Class I events, but not of the shorter Class II bursts. The tail component appears independent of both the duration and brightness of the burst, and may be softer. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Connaughton, V (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 385 EP 389 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400072 ER PT S AU Gehrels, N AF Gehrels, N BE Kippen, RM Mallozzi, RS Fishman, GJ TI The swift gamma-ray burst MIDEX SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID 28 FEBRUARY 1997; AFTERGLOW; REDSHIFT AB Swift is a first of its kind multiwavelength transient observatory for gamma-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of gamma-ray bursts and their afterglows as well as using bursts to probe the early Universe. Swift will also perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field gamma-ray detector, will detect similar to1 gamma-ray burst per day with a sensitivity 5 times that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location in 20 to 70 seconds to determine 0.3-2.5 arcsec positions and perform optical, UV, and X-ray spectrophotometry. On-board measurements of redshift will also be done for hundreds of bursts. Swift will incorporate superb, low-cost instruments using existing flight-spare hardware and designs. Strong education/public outreach and follow-up programs will help to engage the public and astronomical community. Swift has been selected by NASA for development and launch in 2003. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 24 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 671 EP 680 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400125 ER PT S AU Cline, TL Barthelmy, S Butterworth, P McClanahan, T Palmer, D Trombka, J Hurley, K Gold, R Kippen, RM Kouveliotou, C Frederiks, D Golenetskii, S Mazets, E AF Cline, TL Barthelmy, S Butterworth, P McClanahan, T Palmer, D Trombka, J Hurley, K Gold, R Kippen, RM Kouveliotou, C Frederiks, D Golenetskii, S Mazets, E BE Kippen, RM Mallozzi, RS Fishman, GJ TI Progress incorporating the NEAR mission into the interplanetary GRB network SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn AB The present gamma-ray burst (GRB) network consists of the Ulysses and the Near Earth Asteroid Rendezvous missions in deep space, with the BATSE experiment on Compton-GRO, the Konus experiment on GGS-Wind, and the BeppoSAX mission all near to the Earth. The NEAR spacecraft, built and launched without any GRB capability, was modified in Right to provide I-second GR count rates, creating the first 3-cornered long-baseline IPN since the early 1990s. The are-minute precision of this IPN was confirmed with the known locations of SGRs and GRB afterglows. After the Eros orbital insertion maneuver was postponed until February 2000, the NEAR spacecraft was placed in a low bit-rate, dormant mode, but was dedicated to GR data by command. Nest events are now saved, although data recovery is necessarily delayed up to several days. Restoration to the active mode is expected in January 2000. Note: since the Huntsville Symposium, the first all-IPN alert to result in radio and/or optical afterglow observations followed GRB991208. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cline, TL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI McClanahan, Timothy/C-8164-2012; Barthelmy, Scott/D-2943-2012; Frederiks, Dmitry/C-7612-2014; Golenetskii, Sergey/B-3818-2015 NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 726 EP 730 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400135 ER PT S AU Barthelmy, SD Cline, TL Butterworth, P Kippen, RM Briggs, MS Connaughton, V Pendleton, GN AF Barthelmy, SD Cline, TL Butterworth, P Kippen, RM Briggs, MS Connaughton, V Pendleton, GN BE Kippen, RM Mallozzi, RS Fishman, GJ TI GRB coordinates network (GCN): A status report SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID LOCALIZATIONS AB The GRB Coordinates Network (GCN) was designed to deliver locations of GRBs to instruments and observers in real-time (a few seconds) - while the burst is still bursting - so that they can make multi-band simultaneous follow-up observations. This goal has been realized with the optical detection of the burst counterpart for GRB990123 by the ROTSE instrument [1]. A brief review of the function and capabilities of the GCN system is given, the types of GRB location information available plus the distribution methods are described. Complementing the real-time location Notices, the GCN Circulars allow follow up observers to rapidly share the results of their observations with the community. A status report on recent improvements to the GCN system and a list of future improvements is given. One of the keg improvements will be the conversion of the semi-manual RBR LOCBURST locations into the fully automated LOCFAST Notices. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Barthelmy, SD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012 NR 7 TC 23 Z9 23 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 731 EP 735 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400136 ER PT S AU Palmer, DM AF Palmer, DM BE Kippen, RM Mallozzi, RS Fishman, GJ TI Soft gamma repeaters as relaxation systems SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn AB SGR bursts come from sq-stems that accumulate a continuous energy input and release it as discrete bursts. This behavior is analogous to the tectonic systems that produce earthquakes. The fact that these systems can be detected by examining the relationship between burst times and fluences has additional implications, e.g., that burst emission is isotropic. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Palmer, DM (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 661, Greenbelt, MD 20771 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 791 EP 795 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400147 ER PT S AU Marsden, D Lingenfelter, R Rothschild, R Higdon, J AF Marsden, D Lingenfelter, R Rothschild, R Higdon, J BE Kippen, RM Mallozzi, RS Fishman, GJ TI Environmental influences in SGRs and AXPs SO GAMMA-RAY BURSTS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst Symposium CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn ID YOUNG PULSARS; NEUTRON-STAR; SUPERNOVA AB Soft gamma-ray repeaters (SGRs) and anomalous x-ray pulsars (AXPs) are young (<100 kyr), radio-quiet, x-rag pulsars which have been rapidly spun-down to slow spin periods clustered at 5-12 s. Nearly all of these unusual pulsars also appear to be associated with supernova shell remnants (SNRs) with typical ages < 20 kyr. If the unusual properties of SGRs and AXPs are due to an innate feature, such as a superstrong magnetic field, then the pre-supernova environments of SGRs and AXPs should be typical of neutron star progenitors. This is not the case, however, as Re demonstrate that the interstellar media which surrounded the SGR and AXP progenitors and their SNRs were unusually dense compared to the environments around most young radio pulsars and SNRs. Thus, if these SNR associations are real, the SGRs and AXPs can not be "magnetars", and we suggest instead that the environments surrounding SGRs and AXPs play a controlling role in their development. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Marsden, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 847 EP 851 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400158 ER PT S AU Scargle, JD Norris, J Marani, G Bonnell, J AF Scargle, JD Norris, J Marani, G Bonnell, J BE Kippen, RM Mallozzi, RS Fishman, GJ TI Attributes of GRB pulses: An improved Bayesian blocks algorithm for binned data SO GAMMA-RAY BURSTS SE AIP Conference Proceedings LA English DT Proceedings Paper CT 5th Huntsville Symposium on Gamma-Ray Burst CY OCT 18-22, 1999 CL HUNTSVILLE, AL SP Compton Observ Sci Support Ctr, Curry Fdn AB A procedure to estimate temporal locations, amplitudes, widths, rise and decay times of pulses occurring within a large sample of GRB light curves, using BATSE 64-ms concatenated data, is based on an improved version of Bayesian Blocks. It determines the maximum likelihood value of the number of blocks by marginalizing over all the other parameters (block locations and sizes). The blocks are then used to obtain objective, automatic estimates of pulse parameters: which can either be used to study pulse-attribute correlations or as the starting solution for iterative, nonlinear fits of parametric models. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Scargle, JD (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM jeffery@sunshine.arc.nasa.gov; norris@groax0.gsfc.nasa.gov; bonnell@grossc.gsfc.nasa.gov NR 17 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-947-5 J9 AIP CONF PROC PY 2000 VL 526 BP 873 EP 876 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BR50D UT WOS:000166661400163 ER PT S AU Smith, DE Kolenkiewicz, R Dunn, PJ Torrence, MH AF Smith, DE Kolenkiewicz, R Dunn, PJ Torrence, MH BE Schwarz, KP TI Earth scale below a part per billion from Satellite Laser Ranging SO GEODESY BEYOND 2000: THE CHALLENGES OF THE FIRST DECADE SE INTERNATIONAL ASSOCIATION OF GEODESY SYMPOSIA LA English DT Proceedings Paper CT 35th General Assembly of the International-Association-of-Geodesy CY JUL 19-30, 1999 CL BIRMINGHAM, ENGLAND SP Int Assoc Geodesy ID GRAVITATIONAL COEFFICIENT AB Since the LAGEOS I satellite was launched in 1976, the systematic instrument error of the best satellite laser ranging observatories has been steadily reduced to the current level of only a few millimeters. Advances in overall system accuracy, in conjunction with improved satellite, Earth, orbit perturbation and relativity modeling, now allows us to determine the value of the geocentric gravitational coefficient (GM) to less than a part per billion (ppb). This precision has been confirmed by observations of the LAGEOS II satellite, and is supported by results from Starlette, albeit at a lower level of precision. When we consider observations from other geodetic satellites orbiting at a variety of altitudes and carrying somewhat more complex retro-reflector arrays, we obtain consistent measures of scale, which however must be based upon empirically determined, satellite-dependent detector characteristics. We arrive at an estimate of GM of 398600.44187 +/- .00020 km3/sec2, which lies within the 2 ppb uncertainty of the current standard, but differs from it by more than the error of the new estimate. Both the current standard and our recommended value fall comfortably within the ten ppb uncertainty of that determined from the most accurate alternative from lunar laser ranging observations. The precision of the estimate of GM from satellite laser ranging has improved by an order of magnitude in each of the last two decades, and we will discuss projected advances which will result in further refinements of this measure of Earth scale. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Smith, DE (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RI Symposia, IAG/K-2857-2012 NR 23 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0939-9585 BN 3-540-67002-5 J9 IAG SYMP PY 2000 VL 121 BP 3 EP 12 PG 10 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA BQ14R UT WOS:000087305100001 ER PT S AU Vandenberg, NR Thomas, CC Bosworth, JM Chao, B Clark, TA Ma, C AF Vandenberg, NR Thomas, CC Bosworth, JM Chao, B Clark, TA Ma, C BE Schwarz, KP TI CORE: Continuous, high accuracy Earth orientation measurements for the new millennium SO GEODESY BEYOND 2000: THE CHALLENGES OF THE FIRST DECADE SE INTERNATIONAL ASSOCIATION OF GEODESY SYMPOSIA LA English DT Proceedings Paper CT 35th General Assembly of the International-Association-of-Geodesy CY JUL 19-30, 1999 CL BIRMINGHAM, ENGLAND SP Int Assoc Geodesy DE earth orientation; VLBI; earth system science AB The international geodetic VLBI community will inaugurate during 1999 a new phase of the program called CORE: Continuous Observations of the Rotation of the Earth. The capabilities of the new Mark IV correlators, available in late 1999, will enable greater sensitivity, more frequent observing sessions and improved system throughput. C1 NVI Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vandenberg, NR (reprint author), NVI Inc, Goddard Space Flight Ctr, Code 920-1, Greenbelt, MD 20771 USA. RI Ma, Chopo/D-4751-2012; Symposia, IAG/K-2857-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0939-9585 BN 3-540-67002-5 J9 IAG SYMP PY 2000 VL 121 BP 20 EP 21 PG 2 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA BQ14R UT WOS:000087305100003 ER PT J AU McKinley, JP Stevens, TO Westall, F AF McKinley, JP Stevens, TO Westall, F TI Microfossils and paleoenvironments in deep subsurface basalt samples SO GEOMICROBIOLOGY JOURNAL LA English DT Article DE microfossils; paleoenvironments; biogeochemistry; exobiology ID MARTIAN METEORITE ALH84001; LIFE; WASHINGTON; MINERALS; BACTERIA; AQUIFERS; SPRINGS; ROCK; MARS AB Secondary minerals near and within fractures in Columbia River basalts contain objects the size and shape of bacteria. These bacteriomorphs are most commonly rods or ellipses but also include cocci and diplococci forms, vibrioids and club-shaped rods, and associated pairs of objects that suggest cellular division by binary fission. Secondary minerals associated with, enclosing, and making up bacteriomorphs include iron oxyhydroxides, sulfides, and smectites containing ferrous iron. The secondary minerals are intimately intermixed with kerogen. Moreover; bacteriomorphs in the pyrite consist of kerogen. Careful consideration of mineral associations, the occurrence of organic carbon, and the spatial context of bacteriomorphs indicate that they are microfossils. The association of microfossils with minerals formed in reducing environments suggests an ancient ecosystem dominated at least. in part by sulfate-reducing bacteria, similar to communities within these basalts today. C1 Pacific NW Natl Lab, Richland, WA USA. Lyndon B Johnson Space Ctr, Houston, TX USA. RP McKinley, JP (reprint author), Mail Stop K3-61,Battelle Blvd,POB 999, Richland, WA 99352 USA. NR 33 TC 39 Z9 40 U1 1 U2 4 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0149-0451 J9 GEOMICROBIOL J JI Geomicrobiol. J. PD JAN-MAR PY 2000 VL 17 IS 1 BP 43 EP 54 PG 12 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 293VX UT WOS:000085875200004 ER PT J AU Crider, D Cloutier, P Law, C Walker, P Chen, Y Acuna, M Connerney, J Mitchell, D Lin, R Anderson, K Carlson, C McFadden, J Reme, H Mazelle, C d'Uston, C Sauvaud, J Vignes, D Brain, D Ness, N AF Crider, D Cloutier, P Law, C Walker, P Chen, Y Acuna, M Connerney, J Mitchell, D Lin, R Anderson, K Carlson, C McFadden, J Reme, H Mazelle, C d'Uston, C Sauvaud, J Vignes, D Brain, D Ness, N TI Evidence of electron impact ionization in the magnetic pileup boundary of Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VENUS; IONOSPHERE; IONOPAUSE; FIELD; MODEL AB A sharp decline in electron fluxes is observed in the Mars Global Surveyor Electron Reflectometer data in conjunction with the magnetic pileup boundary. We examine the characteristics of the evolution of the electron distribution function for one orbit. We determine that the spectra can best be explained by electron impact ionization of oxygen and hydrogen. To reproduce the observed spectral evolution, we construct a model of the effects of electron impact ionization on the electron distribution function as a flow element encounters the neutral atmosphere. Using the observed post-shock electron distribution function, we are able to reproduce the observed flux attenuation. We: conclude that electron impact ionization is the physical mechanism responsible for the spectral feature. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rice Univ, Dept Space Phys & Astron, Houston, TX 77005 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Toulouse 3, CNRS, CESR, F-31029 Toulouse, France. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Crider, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI connerney, john/I-5127-2013; Hurley, Dana/F-4488-2015 OI Hurley, Dana/0000-0003-1052-1494 NR 16 TC 44 Z9 44 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 45 EP 48 DI 10.1029/1999GL003625 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300013 ER PT J AU Vignes, D Mazelle, C Rme, H Acuna, MH Connerney, JEP Lin, RP Mitchell, DL Cloutier, P Crider, DH Ness, NF AF Vignes, D Mazelle, C Rme, H Acuna, MH Connerney, JEP Lin, RP Mitchell, DL Cloutier, P Crider, DH Ness, NF TI The Solar Wind interaction with Mars: locations and shapes of the Bow Shock and the Magnetic Pile-up Boundary from the observations of the MAG/ER experiment onboard Mars Global Surveyor SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID POSITION; FIELDS; PHOBOS AB The Mars Global Surveyor spacecraft, was inserted into an elliptical orbit around Mars on September 12, 1997. It includes the MAG/ER instrument with two magnetometers providing in-situ sensing of the ambient magnetic field and an electron reflectometer measuring the local distribution function of the electrons in the energy range of 10 eV to 20 keV. This statistical study deals With the identification and the position of the Bow Shock (BS) and of another plasma boundary, the Magnetic Pile-up Boundary (MPB), proved as permanent by MAG/ER. During the first year of the MGS mission, a total of 290 orbits have been considered to fit the-geometric characteristics of these boundaries. The position and shape of these boundaries are compared with previous studies.:Good agreement is found with the Phobos 2 observations, suggesting than the mean bow shock and MPB locations are independent of solar cycle phase. The great number of crossings shows-that-the Bow Shock position and nightside MPB position are highly variable. C1 Ctr Etud Spatiale Rayonnements, Toulouse, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Rice Univ, Dept Space Phys & Astron, Houston, TX 77251 USA. Bartol Res Inst, Newark, NJ USA. RP Vignes, D (reprint author), Ctr Etud Spatiale Rayonnements, Toulouse, France. RI connerney, john/I-5127-2013; Hurley, Dana/F-4488-2015 OI Hurley, Dana/0000-0003-1052-1494 NR 14 TC 166 Z9 170 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 49 EP 52 DI 10.1029/1999GL010703 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300014 ER PT J AU Goldstein, BE Neugebauer, M Zhang, LD Gary, SP AF Goldstein, BE Neugebauer, M Zhang, LD Gary, SP TI Observed constraint on proton-proton relative velocities in the solar wind SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INSTABILITIES AB From June 1994 to December 1995 the Ulysses spacecraft was within 3 AU of the Sun and traveled from high southern to high northern heliospheric latitudes. For this period, SWOOPS instrument data obtained when the magnetic field was approximately aligned with the radial direction from the Sun have been analyzed. In the fast wind at high latitudes, two resolvable proton components are typically present. Statistical studies of the relative densities and the field- aligned velocity difference, upsilon(omicron), of the two components are carried out, considering the dependence on distance from the Sun, the local Alfven speed, and the type of solar wind flow. The observed values of upsilon(omicron)/upsilon(A), where upsilon(A) is the local Alfven speed, are less than the upper bound determined from the linear theory for electromagnetic proton-proton instabilities. This result is good evidence that these microinstabilities constrain the relative streaming of the two components in the solar wind. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Dynam Engn, Pasadena, CA 91101 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Goldstein, BE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 63 Z9 64 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 53 EP 56 DI 10.1029/1999GL003637 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300015 ER PT J AU Moldwin, MB Ford, S Lepping, R Slavin, J Szabo, A AF Moldwin, MB Ford, S Lepping, R Slavin, J Szabo, A TI Small-scale magnetic flux ropes in the solar wind SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MASS EJECTION; RECONNECTION; CLOUDS; PLASMOIDS; DROPOUTS; EVENTS; SHOCK; LOOP AB Small-scale magnetic flux ropes have been discovered in the solar wind at 1 AU in observations from the IMP 8 and WIND spacecraft. These small magnetic structures (diameter of 270 R-E, on average) have some similar properties to magnetic clouds:(diameters of 0.2 -0.3 AU or about 6000 - 8000 R-E), which are:well known large-scale magnetic flux ropes, but have durations of 10s of minutes as opposed to many hours or days for most magnetic clouds. The presence of these small helical field structures suggests that solar wind flux ropes may have a wide-range of scale sizes, or possibly have a bimodal size distribution, and are perhaps more common than previously estimated. Similarities and differences with magnetic clouds will be discussed. We suggest that these small scale magnetic flux ropes are signatures of magnetic reconnection in the solar wind as opposed to-in the solar corona. C1 Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Moldwin, MB (reprint author), Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. RI Moldwin, Mark/F-8785-2011; Slavin, James/H-3170-2012 OI Moldwin, Mark/0000-0003-0954-1770; Slavin, James/0000-0002-9206-724X NR 24 TC 81 Z9 87 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 57 EP 60 DI 10.1029/1999GL010724 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300016 ER PT J AU Dwyer, JR Mason, GM Desai, MI Mazur, JE von Rosenvinge, TT AF Dwyer, JR Mason, GM Desai, MI Mazur, JE von Rosenvinge, TT TI The spatial size of ion events measured fair upstream of the earth's bow shock by ACE/ULEIS and WIND/STEP SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WIND SPACECRAFT; ACCELERATION; ISEE-3 AB Using ACE/ULEIS and WIND/STEP >40 keV ion measurements, we have calculated the probability of simultaneously observing ion events upstream of the earth's bow shock as a function of the lateral separation (in Y-GSE and Z(GSE)) of the two spacecraft, thus providing a quantitative measurement of the spatial size of upstream ion events. Our survey consisted of 202 days in 1997 and 1998 when the ACE and WIND spacecraft were near the first Lagrangian point, approximately 200 R-E upstream of the earth. We find that for lateral separations of up to 70 R-E, the coincidence rate of events at the two spacecraft remains high and conclude that the source region of the upstream ions is large when compared to the site of the bow shock. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Aerospace Corp, El Segundo, CA 90245 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Dwyer, JR (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NR 17 TC 7 Z9 7 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 65 EP 68 DI 10.1029/1999GL003670 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300018 ER PT J AU Mehta, VM Suarez, MJ Manganello, JV Delworth, TL AF Mehta, VM Suarez, MJ Manganello, JV Delworth, TL TI Oceanic influence on the North Atlantic Oscillation and associated Northern Hemisphere climate variations: 1959-1993 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SST ANOMALIES; PRECIPITATION AB The North Atlantic Oscillation (NAO) exhibits variations at interannual to multidecadal time scales and is associated with climate variations over eastern North America, the North Atlantic, Europe, and North Africa. Therefore, it is very important to understand causes of these NAO variations and assess their predictability. It has been hypothesized, based on observations, that sea surface temperature (SST) and sea-ice variations in the North Atlantic Ocean influence the NAG. We describe results of an ensemble of Sixteen experiments with an atmospheric general circulation model in which we used observed SST and sea-ice boundary conditions globally during 1949-1993. We show that multiyear NAO and associated climate variations can be simulated reasonably accurately if results from a large number of experiments are averaged. We also show that the ambiguous results of previous NAO modeling studies were strongly influenced by the ensemble size, which was much smaller than that in the present study. The implications of these results for understanding and predictability of the NAO are discussed. C1 Univ Maryland, Dept Meteorol, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SM&A Corp, Vienna, VA 22180 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Mehta, VM (reprint author), Univ Maryland, Dept Meteorol, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RI Delworth, Thomas/C-5191-2014 NR 12 TC 111 Z9 113 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 121 EP 124 DI 10.1029/1999GL002381 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300032 ER PT J AU Pilewskie, P Rabbette, M Bergstrom, R Marquez, J Schmid, B Russell, PB AF Pilewskie, P Rabbette, M Bergstrom, R Marquez, J Schmid, B Russell, PB TI The discrepancy between measured and modeled downwelling solar irradiance at the ground: Dependence on water vapor SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIATIVE FLUXES; ABSORPTION; CLOUDS AB Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were: measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias: was highly correlated with water vapor and increased at a: rate of 9 Wm(-2) per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth; on water vapor. C1 NASA, Div Earth Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, San Francisco, CA USA. MIT, Dept Aeronaut & Astronaut, Boston, MA USA. RP Pilewskie, P (reprint author), NASA, Div Earth Sci, Ames Res Ctr, M-S 245-4, Moffett Field, CA 94035 USA. NR 23 TC 10 Z9 10 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 1 PY 2000 VL 27 IS 1 BP 137 EP 140 DI 10.1029/1999GL011085 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 273QX UT WOS:000084719300036 ER PT S AU Gorham, PW van Zee, L Unwin, SC Jacobs, CS AF Gorham, PW van Zee, L Unwin, SC Jacobs, CS BE Dingus, BL Salamon, MH Kieda, DB TI The probable binary galaxy system MKN 421: kinematics & structure from optical observations SO GEV-TEV GAMMA RAY ASTROPHYSICS WORKSHOP SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 6th Workshop on GeV-TeV Gamma Ray Astrophysics CY AUG 13-16, 1999 CL SNOWBIRD, UT SP Hamamatsu Corp, NASA AB We present Hubble Space Telescope (HST) imagery, and ground-based spectroscopy and CCD photometry of the active galaxy Markarian 421 and its companion galaxy 14 arcsec to the ENE. The HST images indicate that the companion is a morphological spiral rather than elliptical as previous ground-based imaging has concluded. The companion has a bright, compact nucleus, appearing unresolved in the HST images. This is suggestive of Seyfert activity, or possibly a highly luminous compact star cluster. We also report the results of high dynamic range long-slit spectroscopy with the slit placed to extend across both galaxies and nuclei. Velocities derived from a number of absorption lines visible in both galaxies indicate that the two systems are probably tidally bound and thus in close physical proximity. Using the measured relative velocities, we derive a lower limit on the MKN 421 mass within the companion orbit (R similar to 10 kpc) of 5.9 X 10(11) solar masses, and a mass-to-light ratio of greater than or equal to 17. Our spectroscopy also shows for the first time the presence of H alpha and [NII] emission Lines from the nucleus of MKN 421. We see both broad and narrow line emission, with a velocity dispersion of several thousand km s(-1) evident in the broad lines. Based on the imagery and broad-line velocity dispersion we find evidence for a black hole with mass of order 10(9) M. at the center of MKN 421. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gorham, PW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-938-6 J9 AIP CONF PROC PY 2000 VL 515 BP 165 EP 169 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39A UT WOS:000088226700025 ER PT S AU Baring, MG AF Baring, MG BE Dingus, BL Salamon, MH Kieda, DB TI Modelling hard gamma-ray emission from supernova remnants SO GEV-TEV GAMMA RAY ASTROPHYSICS WORKSHOP SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 6th Workshop on GeV-TeV Gamma Ray Astrophysics CY AUG 13-16, 1999 CL SNOWBIRD, UT SP Hamamatsu Corp, NASA ID SHOCK ACCELERATION; COSMIC-RAYS; PARTICLE-ACCELERATION; SN-1006; ENERGY; ORIGIN; RADIO; EVOLUTION AB The observation by the CANGAROO experiment of TeV emission from SN 1006, in conjunction with several instances of non-thermal X-ray emission from supernova remnants, has led to inferences of super-TeV electrons in these extended sources. While this is sufficient to propel the theoretical community in their modelling of particle acceleration and associated radiation, the anticipated emergence in the next decade of a number of new experiments probing the TeV and sub-TeV bands provides further substantial motivation for modellers. In particular, the quest for obtaining unambiguous gamma-ray signatures of cosmic ray ion acceleration defines a "Holy Grail" for observers and theorists alike. This review summarizes theoretical developments in the prediction of MeV-TeV gamma-rays from supernova remnants over the last five years, focusing on how global properties of models can impact, and be impacted by, hard gamma-ray observational programs, thereby probing the supernova remnant environment. Properties of central consideration include the maximum energy of accelerated particles, the density of the unshocked interstellar medium, the ambient magnetic field, and the relativistic electron-to-proton ratio. Criteria for determining good candidate remnants for observability in the TeV band are identified. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Baring, MG (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 42 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-938-6 J9 AIP CONF PROC PY 2000 VL 515 BP 173 EP 182 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39A UT WOS:000088226700026 ER PT S AU Baring, MG AF Baring, MG BE Dingus, BL Salamon, MH Kieda, DB TI High-energy spectral signatures in gamma-ray bursts SO GEV-TEV GAMMA RAY ASTROPHYSICS WORKSHOP SE AIP Conference Proceedings LA English DT Proceedings Paper CT 6th Workshop on GeV-TeV Gamma Ray Astrophysics CY AUG 13-16, 1999 CL SNOWBIRD, UT SP Hamamatsu Corp, NASA ID ABSORPTION; PHOTONS AB One of the principal results obtained by the EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) was the detection of several gamma-ray bursts (GRBs) above 100 MeV. The broad-band spectra obtained for these bursts gave no indication of any high energy spectral attenuation that might preclude detection of bursts by ground-based Cerenkov telescopes (ACTs), thus motivating several TeV observational programs. This paper explores the expectations for the spectral properties in the TeV and sub-TeV bands for bursts, in particular how attenuation of photons by pair creation internal to the source modifies the spectrum to produce distinctive spectral signatures. The energy of spectral breaks and the associated spectral indices provide valuable information that can constrain the bulk Lorentz factor of the GRB outflow at a given time. These characteristics define palpable observational goals for ACT programs. and strongly impact the observability of bursts in the TeV band. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Baring, MG (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. EM baring@lheavx.gsfc.nasa.gov NR 16 TC 10 Z9 10 U1 2 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-938-6 J9 AIP CONF PROC PY 2000 VL 515 BP 238 EP 242 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39A UT WOS:000088226700035 ER PT S AU Kniffen, DA Bertsch, DL Gehrels, N AF Kniffen, DA Bertsch, DL Gehrels, N BE Dingus, BL Salamon, MH Kieda, DB TI The Gamma-ray Large Area Space Telescope (GLAST) SO GEV-TEV GAMMA RAY ASTROPHYSICS WORKSHOP SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 6th Workshop on GeV-TeV Gamma Ray Astrophysics CY AUG 13-16, 1999 CL SNOWBIRD, UT SP Hamamatsu Corp, NASA ID HIGH-ENERGY; SUPERNOVA-REMNANTS; EGRET OBSERVATIONS; LONG-DURATION; RADIATION; PULSARS; EMISSION; GEMINGA AB The Gamma-ray Large Area Space Telescope is planned as NASA's next major mission in high-energy gamma- ray astronomy. It is included in the Space Science Enterprise Strategic Plan as a 2002 "New Start" with a planned 2005 launch. NASA commissioned a Facility Science Team (FST) of both advocates and non-advocates to establish the framework of the mission. The FST developed a Science Requirements Document that outlines the specifications of an instrument needed to make the next advance in this field. The adopted specifications will lead to an investigation with an energy response extending to 300 GeV, ten times higher than the EGRET instrument on the Compton Observatory, and with a source sensitivity 50 times greater. In addition there would be gains in spectral and spatial resolution. A heavy emphasis will be placed on multi-wavelength observations to maximize the science from the mission. C1 NASA Headquarters, Washington, DC 20024 USA. RP Kniffen, DA (reprint author), NASA Headquarters, 300 E St SW, Washington, DC 20024 USA. NR 28 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-938-6 J9 AIP CONF PROC PY 2000 VL 515 BP 492 EP 499 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ39A UT WOS:000088226700077 ER PT J AU Zimmermann, R Schulze, ED Wirth, C Schulze, EE McDonald, KC Vygodskaya, NN Ziegler, W AF Zimmermann, R Schulze, ED Wirth, C Schulze, EE McDonald, KC Vygodskaya, NN Ziegler, W TI Canopy transpiration in a chronosequence of Central Siberian pine forests SO GLOBAL CHANGE BIOLOGY LA English DT Article DE canopy conductance; microclimate; Pinus sylvestris; sapwood area; Siberia; transpiration; xylem flux ID XYLEM SAP FLOW; BOREAL FOREST; CONDUCTANCE; BIOMASS; PLANTS; TREES AB Tree transpiration was measured in 28, 67, 204 and 383-y-old uniform stands and in a multicohort stand (140-430 y) of Pinus sylvestris ssp. sibirica Lebed. in Central Siberia during August 1995. In addition transpiration of three codominant trees was monitored for two years in a 130-y-old stand. All stands established after fire. Leaf area index (LAI) ranged between 0.6 (28-y-old stand) and 1.6 for stands older than 67-y. Stand xylem area at 1.3 m height increased from 4 cm(2) m(-2) (28-y) to 11.5 cm(2) m(-2) (67-y) and decreased again to 7 cm(2) m(-2) in old stands. Above-ground living biomass increased from 1.5 kg dry weight m(-2) (28-y) to 14 kg dry weight m(-2) (383-y). Day-to-day variation of tree transpiration in summer was dependent on net radiation, vapour pressure deficit, and soil water stress. Tree-to-tree variation of xylem flux was small and increased with heterogeneity in canopy structure. Maximum rates of xylem flux density followed the course of net radiation from mid April when a constant level of maximum rates was reached until mid September when low temperatures and light strongly reduced flux density. Maximum sap flux density (60 g m(-2) s(-1)) and canopy transpiration (1.5 mm d(-1)) were reached in the 67-y stand. Average canopy transpiration of all age classes was 0.72 +/- 0.3 mm d(-1.) Canopy transpiration (E) was not correlated with LAI but related to stand sapwood area SA (E = - 0.02 + 1.15SA R-2) which was determined by stand density and tree sapwood area. C1 Univ Bayreuth, Dept Plant Ecol, Forest Ecol & Remote Sensing Grp, D-95440 Bayreuth, Germany. Max Planck Inst Biogeochem, D-07743 Jena, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Russian Acad Sci, Sukachev Lab Inst Evolut & Ecol Problems, Moscow 117071, Russia. Comenius Univ, Dept Biophys & Chem Phys, SK-84215 Bratislava, Slovakia. RP Zimmermann, R (reprint author), Univ Bayreuth, Dept Plant Ecol, Forest Ecol & Remote Sensing Grp, Univ Str 30, D-95440 Bayreuth, Germany. RI Schulze, Ernst-Detlef/K-9627-2014 NR 30 TC 47 Z9 49 U1 0 U2 9 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1354-1013 J9 GLOB CHANGE BIOL JI Glob. Change Biol. PD JAN PY 2000 VL 6 IS 1 BP 25 EP 37 DI 10.1046/j.1365-2486.2000.00289.x PG 13 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 299GD UT WOS:000086189700003 ER PT J AU Esaias, WE Iverson, RL Turpie, K AF Esaias, WE Iverson, RL Turpie, K TI Ocean province classification using ocean colour data: observing biological signatures of variations in physical dynamics SO GLOBAL CHANGE BIOLOGY LA English DT Article DE environment classification; equations; export; ocean dynamics; phytoplankton; production ID PACIFIC SUBTROPICAL GYRE; CHLOROPHYLL CONCENTRATIONS; NORTHEAST PACIFIC; TROPICAL PACIFIC; EL-NINO; PHYTOPLANKTON; SEA; SCANNER; VARIABILITY; SCALE AB We have used satellite colour data to classify ocean environments for monitoring interannual changes in the ocean. The unsupervised classification method is based on our observation that the frequency distributions of Coastal Zone Color Scanner (CZCS) annual pigment means and standard deviations are nonuniform and contain distinct clusters. The frequency distributions are used to objectively determine ocean areas with similar pigment statistical characteristics. A major separation between high variance, high pigment and lower variance, lower pigment waters is observed in terms of global ocean area. The ocean areas determined with our method reflect different bio-logical responses to variations in ocean physical dynamics. Pigment means and variances around the Joint Global Ocean Flux Study (JGOFS) Time Series stations are used as fiducial characteristics. Hawaii Ocean Time-series (HOT) station is associated with the low-variance portion of the global annual pigment distribution characteristic of the central gyres, but shows slightly higher mean and variance than the minima in the central Pacific gyre. The Bermuda Atlantic Time Series (BATS) pigment associations comprise a transitional region between the gyres and high-variance pigment areas, and circumscribe the HOT pigment associations. Together, these associations encompass 23% (HOT-like) and 48% (BATS-like) of the Northern Hemisphere open ocean. The Pacific regions delineated by the JGOFS station pigment-based patterns are similar to distributions described historically for Pacific zooplankton communities. Interannual variation for the northern hemisphere gyre area is on the order of by 10% for the 11/78-10/81 period. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. Gen Sci Corp, Laurel, MD 20707 USA. RP Esaias, WE (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 51 TC 12 Z9 13 U1 2 U2 4 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1354-1013 J9 GLOB CHANGE BIOL JI Glob. Change Biol. PD JAN PY 2000 VL 6 IS 1 BP 39 EP 55 DI 10.1046/j.1365-2486.2000.00285.x PG 17 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 299GD UT WOS:000086189700004 ER PT J AU Iverson, RL Esaias, WE Turpie, K AF Iverson, RL Esaias, WE Turpie, K TI Ocean annual phytoplankton carbon and new production, and annual export production estimated with empirical equations and CZCS data SO GLOBAL CHANGE BIOLOGY LA English DT Article DE ocean; phytoplankton; export; production; empirical; equations ID PARTICULATE ORGANIC-CARBON; PACIFIC-OCEAN; SATELLITE CHLOROPHYLL; EQUATORIAL PACIFIC; NORTH-ATLANTIC; NITRATE UPTAKE; SURFACE-OCEAN; QUANTUM YIELD; STATION ALOHA; VERTICAL FLUX AB Empirical equations are parameterized for use with chlorophyll a, derived from satellite ocean colour data, to calculate phytoplankton carbon production, phytoplankton new production, and export production. For environments in a high variance (HV) pigment statistical class, annual phytoplankton particulate organic carbon production (AIP) is linearly related to annual average in situ chlorophyll a within the near-surface layer. Linear relations were also obtained between AIP and annual new nitrogen production, and between AIP and particulate organic carbon annually exported from the euphotic zone for environments in that class. We found no relation between AIP and C(SFC), or between the annual production variables, for oceanic environments characterized by low pigment variance (LV). Ratios of export production to AIP, called e, and new production to nitrogen annually used in phytoplankton production, called f, are widely used to express marine food web processes. The trends of these ratios with AIP differ between HV and LV environments. This is a result of differences in the coupling between nitrogen and carbon transfer in pelagic food webs, which contain different organism size classes in HV compared to LV environments. We applied the empirical equations to CZCS data to estimate global new and export production. The HV environments are responsible for about 40% of global ocean annual phytoplankton carbon production and 70% of global ocean annual new and export production. C1 Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. Gen Sci Corp, Laurel, MD 20707 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Iverson, RL (reprint author), Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. EM iverson@ocean.fsu.edu NR 100 TC 17 Z9 19 U1 1 U2 7 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD JAN PY 2000 VL 6 IS 1 BP 57 EP 72 DI 10.1046/j.1365-2486.2000.00286.x PG 16 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 299GD UT WOS:000086189700005 ER PT B AU Levine, E Kimes, D Fifer, S Nelson, R AF Levine, E Kimes, D Fifer, S Nelson, R BE Lal, R Kimble, JM Stewart, BA TI Evaluating tropical soil properties with pedon data, satellite imagery, and neural networks SO GLOBAL CLIMATE CHANGE AND TROPICAL ECOSYSTEMS SE Advances in Soil Science LA English DT Proceedings Paper CT Workshop on Carbon Pools and Dynamics in Tropical Ecosystems CY DEC 01-05, 1997 CL BELEM, BRAZIL SP Ohio State Univ, USDA, NRCS, EMBRAPA, CPATU C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Levine, E (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. RI Nelson, Ross/H-8266-2014 NR 20 TC 2 Z9 2 U1 0 U2 0 PU CRC PRESS-TAYLOR & FRANCIS GROUP PI BOCA RATON PA 6000 BROKEN SOUND PARKWAY NW, STE 300, BOCA RATON, FL 33487-2742 USA BN 1-56670-485-5 J9 ADV SOIL SCI-SER JI Adv. Soil Sci. PY 2000 BP 365 EP 374 PG 10 WC Ecology; Environmental Sciences; Meteorology & Atmospheric Sciences; Soil Science SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Agriculture GA BP56X UT WOS:000085521600019 ER PT B AU Divsalar, D Dolinar, S Pollara, F AF Divsalar, D Dolinar, S Pollara, F GP IEEE IEEE TI Serial concatenated trellis coded modulation with rate-1 inner code SO GLOBECOM '00: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1- 3 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 00) CY NOV 27-DEC 01, 2000 CL SAN FRANCISCO, CA SP IEEE, IEEE, Commun Soc, Internet Soc, ICC GLOBECOM, Telesys Software, AT&T, SPIE, Opt Networks Magazine, Net Gen Learning Syst, MathWorks Inc, Kluwer Acad Publishers, John Wiley & Sons AB We develop new, low complexity turbo codes suitable for bandwidth and power limited systems, for very low bit and word error rate requirements. Motivated by the structure of recently discovered low complexity codes such as Repeat-Accumulate (RA) codes with low density parity check matrix, we extend the structure to high-level modulations such as 8PSK, and 16QAM. The structure consists of a simple 4-state convolutional or short block code as an outer code, and a rate-1, 2 or 4-state inner code. Two design criteria are proposed: the maximum likelihood design criterion, for short to moderate block sizes, and an iterative decoding design criterion for very long block sizes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Divsalar, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 18 TC 16 Z9 16 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6452-X J9 GLOB TELECOMM CONF PY 2000 BP 777 EP 782 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BR61A UT WOS:000166939500143 ER PT B AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS GP IEEE IEEE TI Multiple symbol differential detection with diversity reception SO GLOBECOM '00: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1- 3 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 00) CY NOV 27-DEC 01, 2000 CL SAN FRANCISCO, CA SP IEEE, IEEE, Commun Soc, Internet Soc, ICC GLOBECOM, Telesys Software, AT&T, SPIE, Opt Networks Magazine, Net Gen Learning Syst, MathWorks Inc, Kluwer Acad Publishers, John Wiley & Sons ID FADING CHANNELS; PERFORMANCE; ERROR AB In this paper, we first consider the maximum-likelihood sequence estimation (MLSE) for multiple symbol differential detection (MSDD) over the slow fading diversity channel. Since this optimum decision metric results in a complex receiver implementation whose average bit error probability (BEP) performance is difficult (if not impossible) to obtain analytically we then focus our attention on evaluating the average BEP for MSDD with diversity reception in the form of postdetection equal-gain combining (EGC) giving emphasis to its ability to bridge the gap between EGC of conventional differentially detected M-PSK and maximal-ratio combining (MRC) of coherently detected M-PSK with differential encoding. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6452-X J9 GLOB TELECOMM CONF PY 2000 BP 985 EP 989 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BR61A UT WOS:000166939500183 ER PT B AU Allman, M Griner, J Richard, A AF Allman, M Griner, J Richard, A GP IEEE IEEE TI TCP behavior in networks with dynamic propagation delay SO GLOBECOM '00: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1- 3 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 00) CY NOV 27-DEC 01, 2000 CL SAN FRANCISCO, CA SP IEEE, IEEE, Commun Soc, Internet Soc, ICC GLOBECOM, Telesys Software, AT&T, SPIE, Opt Networks Magazine, Net Gen Learning Syst, MathWorks Inc, Kluwer Acad Publishers, John Wiley & Sons DE TCP; variable RTT; retransmission; satellite AB This paper provides a preliminary investigation into the impact a link with changing propagation delay has on the performance of TCP file transfers. We investigate over a dozen different variable delay patterns, based on spacecraft movement. We highlight the performance impact of such variability, paying close attention to TCP's retransmission timer, which is based on the observed round-trip time of the network path. In addition, we explore one scenario in which the round-trip time across a network path suddenly changes due to a large change in the path between the two end points. We conclude that the variable delay network paths studied in this paper do not drastically impact TCP performance. C1 NASA, GRC, BBN Technol, Washington, DC 20546 USA. RP Allman, M (reprint author), NASA, GRC, BBN Technol, Washington, DC 20546 USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6452-X J9 GLOB TELECOMM CONF PY 2000 BP 1103 EP 1108 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BR61A UT WOS:000166939500206 ER PT B AU Divsalar, D Biglieri, E AF Divsalar, D Biglieri, E GP IEEE IEEE TI Upper bounds to error probabilities of coded systems over AWGN and Fading Channels SO GLOBECOM '00: IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1- 3 SE IEEE Global Telecommunications Conference (Globecom) LA English DT Proceedings Paper CT IEEE Global Telecommunications Conference (GLOBECOM 00) CY NOV 27-DEC 01, 2000 CL SAN FRANCISCO, CA SP IEEE, IEEE, Commun Soc, Internet Soc, ICC GLOBECOM, Telesys Software, AT&T, SPIE, Opt Networks Magazine, Net Gen Learning Syst, MathWorks Inc, Kluwer Acad Publishers, John Wiley & Sons AB A family of upper bounds to error probabilities of coded systems on the additive white Gaussian noise channel was recently proposed by Divsalar [3]. Their calculation depends only on the weight spectrum of the code words. We first elaborate upon these bounds to show how they can be further tightened by using numerical integration instead of a Chernoff bound, and by reducing the number of code words to be included in the bound. Next, we extend them to fading channels. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Politecn Torino, Turin, Italy. RP Divsalar, D (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Biglieri, Ezio/A-2246-2012 OI Biglieri, Ezio/0000-0002-8867-2455 NR 9 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6452-X J9 GLOB TELECOMM CONF PY 2000 BP 1605 EP 1610 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BR61A UT WOS:000166939500301 ER PT S AU Waluschka, E AF Waluschka, E BE Meshkov, S TI Computing LISA far field phase patterns SO GRAVITATIONAL WAVES SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 3rd Edoardo Amaldi Conference on Gravitational Waves CY JUL 12-16, 1999 CL CALTECH, PASADENA, CA SP Caltech, Dept Phys Math & Astron, US Natl Sci Fdn, Ist Nazl Fis Nucleare, Parsons Corp, Lightwave Electr HO CALTECH C1 NASA, Goddard Space Flight Ctr 5510, Greenbelt, MD 20771 USA. RP Waluschka, E (reprint author), NASA, Goddard Space Flight Ctr 5510, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-944-0 J9 AIP CONF PROC PY 2000 VL 523 BP 401 EP 402 PG 2 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BQ56Y UT WOS:000088786300054 ER PT S AU Cruzen, CA Lomas, JJ Dabney, RW AF Cruzen, CA Lomas, JJ Dabney, RW BE Culp, RD Dukes, EM TI Test results for the Automated Rendezvous and Capture system SO GUIDANCE AND CONTROL 2000 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 23rd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 02-06, 2000 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Automated Rendezvous and Capture (AR&C) system was designed and tested at NASA's Marshall Space Flight Center (MSFC) to demonstrate technologies and mission strategies for automated rendezvous and docking of spacecraft in Earth orbit. The system incorporates some of the latest innovations in Global Positioning System (GPS) space navigation, laser sensor technologies and automated mission sequencing algorithms. The system's initial design and integration was completed in 1998 and underwent testing in 1999. This paper describes the major components of the AR&C system and presents results from the official system tests performed in MSFC's Flight Robotics Laboratory with digital simulations and hardware in the loop tests. The results show that the AR&C system can safely and reliably perform automated rendezvous and docking missions in the absence of system failures. When system failures were included, the system used its automated collision avoidance logic to recover in a safe manner. The primary objective of the AR&C project is to prove that by designing a safe and robust automated system, mission operations cost can be reduced by decreasing the personnel required for mission design, preflight planning and training required for crewed rendezvous and docking missions. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Cruzen, CA (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 8 TC 1 Z9 1 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-468-0 J9 ADV ASTRONAUT SCI PY 2000 VL 104 BP 35 EP 56 PG 22 WC Engineering, Aerospace SC Engineering GA BQ63N UT WOS:000089018600003 ER PT S AU Quinn, DA Folta, DC AF Quinn, DA Folta, DC BE Culp, RD Dukes, EM TI A tethered formation flying concept for the SPECS mission SO GUIDANCE AND CONTROL 2000 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 23rd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 02-06, 2000 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB The Sub-millimeter Probe of the Evolution of Cosmic Structure (SPECS) is a bold new mission concept designed to address fundamental questions about the Universe, including how the first stars formed from primordial material, and the first galaxies from pre-galactic structures, how the galaxies evolve over time, and what the cosmic history of energy release, heavy element synthesis, and dust formation is. Half of the luminosity and 98% of the post Big-Bang photons exit in the sub-millimeter range. The spectrum of our own Milky Way Galaxy shows this, and many galaxies have even more pronounced long-wavelength emissions. There can be no doubt that revolutionary science will be enabled when we have tools to study the sub-millimeter sky with Hubble-Space-Telescope-class resolution and sensitivity. Ideally, a very large telescope with an effective aperture approaching one kilometer in diameter would be needed to obtain such high quality angular resolution at these long wavelengths. However, a single aperture one kilometer in diameter would not only be very difficult to build and maintain at the cryogenic temperatures required for good seeing, but could actually turn out to be serious overkill. Because cosmic sub-millimeter photons are plentiful and the new detectors will be sensitive, the observations needed to address the questions posed above can be made with an interferometer using well established aperture synthesis techniques. Possibly as few as three 3-4 meter diameter mirrors flying in precision formation could be used to collect the light. To mitigate the need for a great deal of propellant, tethers may be needed as well. A spin-stabilized, tethered formation is a possible configuration requiring a more advanced form of formation flying controller, where dynamics are coupled due to the existence of the tethers between nodes in the formation network. The paper presents one such concept, a proposed configuration for a mission concept which combines the best features of structure, tethers and formation flying to meet the ambitious requirements necessary to make a future SPECS mission a success. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Quinn, DA (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 572, Greenbelt, MD 20771 USA. NR 5 TC 9 Z9 9 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-468-0 J9 ADV ASTRONAUT SCI PY 2000 VL 104 BP 183 EP 196 PG 14 WC Engineering, Aerospace SC Engineering GA BQ63N UT WOS:000089018600012 ER PT S AU Chamitoff, GE Dershowitz, AL Bryson, AL AF Chamitoff, GE Dershowitz, AL Bryson, AL BE Culp, RD Dukes, EM TI Command level maneuver optimization for the International Space Station SO GUIDANCE AND CONTROL 2000 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 23rd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 02-06, 2000 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB This paper presents a maneuver commanding optimization tool for minimizing fuel requirements during International Space Station (ISS) guidance, navigation, and control (GN&C) maneuvers. The dynamic behavior of the ISS varies significantly throughout its construction, as mass properties and external aerodynamic shape change with the addition of new components and the attachment and movement of various earth-to-orbit vehicles and payloads. Performance of the GNC system is similarly affected by the vehicle configuration as well as the sequence and timing of commands. In particular, fuel required to achieve and maintain desired attitude depends on the configuration, the environment, the controller used, and the GN&C command sequence. GN&C operations for the ISS are constrained by the ability to issue a specific set of commands, which are limited to certain mode changes, controller parameter updates, attitude commands, and control moment gyro (CMG) momentum commands. An approach for optimizing the command sequence was developed with the objective of minimizing fuel utilization. A high-speed and variable fidelity simulation for the ISS dynamics, environment, and GNC system, was developed and integrated into an optimization code that includes a complete model for the operator commanding capability. Commands, parameters, and time-tags can all be treated as optimization variables. An initial guess for the optimal solution can be supplied by a simplified model using the differential inclusions method. Optimal solutions for the full nonlinear problem are obtained via 3D visualizations of the search space combined with local gradient techniques. This tool will provide ground-based flight controllers with an automated command sequence optimization capability for any GNC operations scenario. Ultimately, this tool could be extended to provide the crew with an onboard autonomous capability for attitude control planning, optimization, and operation. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Chamitoff, GE (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1,Mail Code CB, Houston, TX 77058 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-468-0 J9 ADV ASTRONAUT SCI PY 2000 VL 104 BP 311 EP 326 PG 16 WC Engineering, Aerospace SC Engineering GA BQ63N UT WOS:000089018600019 ER PT S AU Gambino, J AF Gambino, J BE Culp, RD Dukes, EM TI MEMS rate sensors for space SO GUIDANCE AND CONTROL 2000 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 23rd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 02-06, 2000 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB Micromachined Electro Mechanical System (MEMS) Rate Sensors are an enabling technology for Nanosatellites. The recent award of a Nanosatellite program to the Goddard Space Flight Center (GSFC) underscores the urgency of the development of these systems for space use. The Guidance Navigation and Control Center (GNCC) at the GSFC is involved in several efforts to develop this technology. The GNCC seeks to improve the performance of these sensors and develop flight ready systems for spacecraft use by partnering with industry leaders in MEMS Rate Sensor development. This paper introduces Microgyros and discusses the efforts in progress at the GNCC to improve the performance of these units and develop MEMS Rate Sensors for space use. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Gambino, J (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 573, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-468-0 J9 ADV ASTRONAUT SCI PY 2000 VL 104 BP 515 EP 521 PG 7 WC Engineering, Aerospace SC Engineering GA BQ63N UT WOS:000089018600035 ER PT S AU Robertson, B Sabelhaus, P Mendenhall, T Fesq, L AF Robertson, B Sabelhaus, P Mendenhall, T Fesq, L BE Culp, RD Dukes, EM TI The recovery of TOMS-EP SO GUIDANCE AND CONTROL 2000 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 23rd Annual AAS Rocky Mountain Guidance and Control Conference CY FEB 02-06, 2000 CL BRECKENRIDGE, CO SP Amer Astronaut Soc AB On December 13(th) 1998, the Total Ozone Mapping Spectrometer - Earth Probe (TOMS-EP) spacecraft experienced a Single Event Upset which caused the system to reconfigure and enter a Safe Mode. This incident occurred two and a half years after the launch of the spacecraft which was designed for a two year life. A combination of factors, including changes in component behavior due to age and extended use, very unfortunate initial conditions and the safe mode processing logic prevented the spacecraft from entering its nominal long term storage mode. The spacecraft remained in a high fuel consumption mode designed for temporary use. By the time the onboard fuel was exhausted, the spacecraft was Sun pointing in a high rate flat spin. Although the uncontrolled spacecraft was initially in a power and thermal safe orientation, it would not stay in this state indefinitely due to a slow precession of its momentum vector. A recovery team was immediately assembled to determine if there was time to develop a method of despinning the vehicle and return it to normal science data collection. A three stage plan was developed that used the onboard magnetic torque rods as actuators. The first stage was designed to reduce the high spin rate to within the linear range of the gyros. The second stage transitioned the spacecraft from sun pointing to orbit reference pointing. The final stage returned the spacecraft to normal science operation. The entire recovery scenario was simulated with a wide range of initial conditions to establish the expected behavior. The recovery sequence was started on December 28(th) 1998 and completed by December 31(st). TOMS-EP was successfully returned to science operations by the beginning of 1999. This paper describes the TOMS-EP Safe Mode design and the factors which led to the spacecraft anomaly and loss of fuel. The recovery and simulation efforts are described. Flight data are presented which show the performance of the spacecraft during its return to science. Finally, lessons learned are presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Robertson, B (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-468-0 J9 ADV ASTRONAUT SCI PY 2000 VL 104 BP 665 EP 685 PG 21 WC Engineering, Aerospace SC Engineering GA BQ63N UT WOS:000089018600045 ER PT B AU Zhang, NL Yang, WJ Chao, DF AF Zhang, NL Yang, WJ Chao, DF BE Wang, BX TI Critical heat flux in pool boiling on metal-graphite composite surfaces SO HEAT TRANSFER SCIENCE AND TECHNOLOGY 2000 LA English DT Proceedings Paper CT 5th International Symposium on Heat Transfer CY AUG 12-16, 2000 CL BEIJING, PEOPLES R CHINA SP Tsinghua Univ, Inst Thermal Sci & Engn, Natl Nat Sci Fdn China, China State Educ Commiss, Chinese Soc Engn Thermophys DE Pool boiling; Metal-graphite composite surface; critical heat flux; unusual Marangoni effect; microgravity ID CONVECTION AB A study is conducted on high heat-flux pool boiling of pentane on micro-configured composite surfaces. The boiling surfaces are copper-graphite (Cu-Gr) and aluminum-graphite (Al-Gr) composites with a fiber volume concentration of 50%. The micro-graphite fibers embedded in the matrix contribute to a substantial enhancement in boiling heat-transfer performance. Correlation equations are obtained for both the isolated and coalesced bubble regimes, utilizing a mathematical model based on a metal-graphite, two-tier configuration with the aid of experimental data. A new model to predict the critical heat flux (CHF) on the composites is proposed to explain the fundamental aspects of the boiling phenomena. Three different factors affecting the CHF are considered in the model. Two of them are expected to become the main agents driving vapor volume detachment under microgravity conditions, using the metal-graphite composite surfaces as the heating surface and using liquids with an unusual Marangoni effect as the working fluid. C1 NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Zhang, NL (reprint author), NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU CHINA HIGHER EDUCATION PRESS BEIJING PI BEIJING PA 55 SHATAN HOUJIE, BEIJING, PEOPLES R CHINA BN 7-04-008955-6 PY 2000 BP 3 EP 9 PG 7 WC Mechanics SC Mechanics GA BQ82W UT WOS:000089733400001 ER PT B AU Zhang, NL Chao, DF AF Zhang, NL Chao, DF BE Wang, BX TI Effects of evaporation/condensation on spreading and contact angle of a volatile liquid drop SO HEAT TRANSFER SCIENCE AND TECHNOLOGY 2000 LA English DT Proceedings Paper CT 5th International Symposium on Heat Transfer CY AUG 12-16, 2000 CL BEIJING, PEOPLES R CHINA SP Tsinghua Univ, Inst Thermal Sci & Engn, Natl Nat Sci Fdn China, China State Educ Commiss, Chinese Soc Engn Thermophys DE spreading; contact angle; evaporation; condensation ID SURFACES; EVAPORATION AB Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation-retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 mm and less till drying up, though the evaporation rate is gradually slowing down. C1 NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Zhang, NL (reprint author), NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. NR 16 TC 2 Z9 2 U1 0 U2 1 PU CHINA HIGHER EDUCATION PRESS BEIJING PI BEIJING PA 55 SHATAN HOUJIE, BEIJING, PEOPLES R CHINA BN 7-04-008955-6 PY 2000 BP 367 EP 372 PG 6 WC Mechanics SC Mechanics GA BQ82W UT WOS:000089733400046 ER PT B AU Mandzhavidze, N Ramaty, R AF Mandzhavidze, N Ramaty, R BE Ramaty, R Mandzhavidze, N TI Particle acceleration and abundances from gamma-ray line spectroscopy SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID SOLAR-FLARE; HELIUM; RATIO; ATMOSPHERE; HYDROGEN; PROBE AB We review the results of gamma-ray investigations that pro He-3/He-4, on the vide information on the solar flare accelerated alpha/p and ambient He/H, Mg/O, Si/O and Fe/O in subcoronal regions of the solar atmosphere, and on the photospheric He-3/He-4. The data on the 2.223 MeV line from five more flares considered here confirms our previous conclusion that He-3/He-4 in the photosphere is lower than it is in the corona. These findings have major implications on the understanding of solar atmospheric dynamics, solar wind and solar hare particle acceleration and Galactic chemical evolution. We discuss the relevance of the future HESSI data to these important issues. We also present a new method that allows the most straightforward determination of the interacting particle energy spectrum. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mandzhavidze, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 33 TC 6 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 64 EP 70 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000007 ER PT B AU Reames, DV AF Reames, DV BE Ramaty, R Mandzhavidze, N TI What we don't understand about ion acceleration in flares SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID IMPULSIVE SOLAR-FLARES; GAMMA-RAY SPECTROSCOPY; FAST-MODE WAVES; ENERGETIC PARTICLES; ELECTRON ACCELERATION; CORONAL ABUNDANCES; HE-3-RICH EVENTS; HE-3; SPECTRA; EVOLUTION AB There are now strong associations between the He-3-rich, Fe-rich ions in "impulsive" solar energetic particle (SEP) events and the similar abundances derived from gamma-ray lines from flares. Compact flares, where wave energy can predominate, are ideal sites for the study of wave-particle physics. Yet there are nagging questions about the magnetic geometry, the relation between ions that escape and those that interact, and the relative roles of cascading Alfven waves and the EMIC waves required to enhance He-3. Then are also questions about the relative timing of ion and electron acceleration and of heating; these relate to the variation of ionization states before and during acceleration and during transport out of the corona. We can construct a model that addresses many of these issues, but problems do remain. Our greatest lack is realistic theoretical simulations of element abundances, spectra, and their variations. By contrast, we now have a much better idea of the acceleration at CME-driven shock waves in the rare but large "gradual" SEP events, largely because of their slow temporal evolution and great spatial extent. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reames, DV (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 35 TC 10 Z9 10 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 102 EP 111 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000013 ER PT B AU Holman, GD AF Holman, GD BE Ramaty, R Mandzhavidze, N TI Particle acceleration in large-scale DC electric fields SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID IMPULSIVE SOLAR-FLARES; SOFT-X-RAY; MODEL; EMISSION; YOHKOH AB Deducing the physical processes responsible for particle acceleration in solar flares will be a primary challenge for the HESSI project. Acceleration by DC electric fields is a process that is likely to be important for the impulsive phase acceleration of electrons and ions. Models based upon this mechanism have distinctive features that can be tested with HESSI and related observations. These models can be classified into three general categories, characterized by the electric field being less than, on the order of, or greater than the classical Dreicer field. These models are reviewed, with emphasis on their observational consequences. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Holman, GD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Holman, Gordon/C-9548-2012 NR 23 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 135 EP 144 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000018 ER PT B AU Ng, CK Reames, DV Tylka, AJ AF Ng, CK Reames, DV Tylka, AJ BE Ramaty, R Mandzhavidze, N TI Effect of wave generation on the evolution of elemental abundances of solar energetic particles SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID EVENTS AB We explore the possible role of proton amplified waves in impulsive solar energetic particle (SEP) events, following the recent successful explanation of SEP abundance evolution in gradual SEP events in terms of ion transport through proton amplified waves. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ng, CK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tylka, Allan/G-9592-2014 NR 14 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 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 162 EP 166 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000020 ER PT B AU Ragot, BR AF Ragot, BR BE Ramaty, R Mandzhavidze, N TI Scattering of solar cosmic rays SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID QUASI-LINEAR THEORY; TRANSPORT AB Low-frequency, non-resonant plasma waves can very efficiently scatter charged particles through the zero pitch-angle cosine. This effect is used here to fit the parallel mean free path of solar cosmic rays as a function of their rigidity, with an anisotropy of the fast mode deduced from the plasma parameters and the thermal damping rate of this mode. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ragot, BR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 12 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 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 171 EP 174 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000022 ER PT B AU Brosius, JW Woodgate, BE AF Brosius, JW Woodgate, BE BE Ramaty, R Mandzhavidze, N TI Using temporal variations of the nonthermal redshifted Ly-alpha emission to deduce properties of proton beams injected into a stellar atmosphere SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID IMPULSIVE PHASE AB We present theoretical calculations of temporal variations in the nonthermal redshifted Ly-alpha emission due to proton beams injected into a stellar atmosphere. The computations are performed for a power law spectrum of nonthermal proton energies injected into an atmosphere of pure hydrogen in local thermodynamic equilibrium. We characterize the injected proton beams with the total energy flux F and the power law index delta. Based upon trends in observable properties of the calculated emission, proton beam properties can be deduced from sufficiently high quality observations of the nonthermal redshifted Ly-alpha profile. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 682, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012 NR 10 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 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 175 EP 178 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000023 ER PT B AU Newton, E Giblin, T Metcalf, T AF Newton, E Giblin, T Metcalf, T BE Ramaty, R Mandzhavidze, N TI Anticipating HESSI's spatially resolved view of spectral evolution SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND AB The spectral evolution of observed flares' hard X-ray emission is found to conform to certain patterns in color-color diagrams. By combining the spectral resolution of BATSE data with the spatial resolution of HXT data, we are able to address the nature of flare energy release and anticipate what kind of observations HESSI may make of the energy release/particle acceleration site in flares. C1 NASA, MSFC, Huntsville, AL 35814 USA. RP Newton, E (reprint author), NASA, MSFC, Huntsville, AL 35814 USA. NR 3 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 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 272 EP 275 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000041 ER PT B AU Desai, U Orwig, LE Mertz, L Gaither, CC Gibson, W AF Desai, U Orwig, LE Mertz, L Gaither, CC Gibson, W BE Ramaty, R Mandzhavidze, N TI Shadow mask telescope for high energy X-rays SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND AB The study of transient astrophysical phenomena (e.g. solar flares, x-ray bursters, and gamma ray bursts) needs the development of new instruments capable of simultaneously making measurements with high spatial, temporal, and spectral resolution. Detectors for high spectral and temporal measurments do exist. However, for imaging at high energies only a few options are available. Shadow casting techniques have been employed to image hard x-rays. These techniques employ total absorption of x-rays and gamma rays to indirectly achieve imaging. We describe a design for an x-ray telescope based on a two shadow masks which resemble Fresnel Zone Plates (FZP) (although they do not involve any diffraction) which give simple straight bands for well separated point sources. Such plates are in principle suitable for use on small satellites. Most single plane coded aperture imaging requires very high spatial resolution detectors to achieve high angular resolution. In our scheme the image plane detector can have coarse resolution, but still provide high angular resolution since it has only to resolve the Moire-fringes rather than the finest features of the zone plate. The telescope that we have developed uses Bone plates made from 1mm-thick tungsten with a finest feature of 41 microns. We present very preliminary results of exposure of such a telescope to a nearly parallel x-ray beam. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Desai, U (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 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 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 284 EP 288 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000044 ER PT B AU Gopalswamy, N Kaiser, ML Sato, J Pick, M AF Gopalswamy, N Kaiser, ML Sato, J Pick, M BE Ramaty, R Mandzhavidze, N TI Shock wave and EUV transient during a flare SO HIGH ENERGY SOLAR PHYSICS - ANTICIPATING HESSI SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on High Energy Solar Physics - Anticipating HESSI CY OCT 18-20, 1999 CL UNIV MARYLAND, COLLEGE PK, MD SP Goddard Space Flight Ctr HO UNIV MARYLAND ID RADIO AB A metric type II burst and a 'brow' type enhancement in EUV were observed during the hard X-ray flare of 1997 April 15 from a newly emerging region, AR 8032. The position of the type II burst obtained from the Nancay radioheliograph coincided with the EUV transient. The type II burst and the EUV transient were in the equatorial streamer region to the north of the flaring region. This observation suggests that the EUV transient may be the manifestation of the MI-ID shock responsible for the type II burst. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Gopalswamy, Nat/D-3659-2012 NR 6 TC 20 Z9 20 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-033-1 J9 ASTR SOC P PY 2000 VL 206 BP 351 EP 354 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BQ80Q UT WOS:000089621000056 ER PT S AU Jin, HQ Frumkin, M Yan, J AF Jin, HQ Frumkin, M Yan, J BE Valero, M Joe, K Kitsuregawa, M Tanaka, H TI Automatic generation of OpenMP directives and its application to computational fluid dynamics codes SO HIGH PERFORMANCE COMPUTING, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Symposium on High Performance Computing (ISHPC 2000) CY OCT 16-18, 2000 CL TOKYO, JAPAN SP Kao Fdn Arts & Sci, Inoue Fdn Sci, Telecommun Adv Fdn, Sumisho Electr Co Ltd AB The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate OpenMP-based parallel program with nominal user assistance. We outline techniques used in the implementation of the tool and discuss the application of this tool on the NAS Parallel Benchmarks and several computational fluid dynamics codes. This work demonstrates the great potential of using the tool to quickly port parallel programs and also achieve good performance that exceeds some of the commercial tools. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, NAS Syst Div, Moffett Field, CA 94035 USA. RP Jin, HQ (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. NR 15 TC 10 Z9 10 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41128-3 J9 LECT NOTES COMPUT SC PY 2000 VL 1940 BP 440 EP 456 PG 17 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BT81P UT WOS:000174115000042 ER PT J AU Yang, HX Prewitt, CT AF Yang, HX Prewitt, CT TI Chain and layer silicates at high temperatures and pressures SO HIGH-TEMPERATURE AND HIGH-PRESSURE CRYSTAL CHEMISTRY SE REVIEWS IN MINERALOGY & GEOCHEMISTRY LA English DT Review ID CRYSTAL X-RAY; MG ORDER-DISORDER; PHASE-TRANSITION; ORTHO-PYROXENE; THERMODYNAMIC PROPERTIES; CHEMISTRY; CLINOPYROXENES; COMPRESSIBILITY; DIFFRACTION; DIOPSIDE C1 Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. Carnegie Inst Washington, Ctr High Pressure Res, Washington, DC 20015 USA. RP Yang, HX (reprint author), NASA, Jet Prop Lab, Pasadena, CA 91125 USA. NR 101 TC 36 Z9 36 U1 0 U2 7 PU MINERALOGICAL SOC AMERICA PI WASHINGTON PA 1015 EIGHTEENTH ST, NW, SUITE 601, WASHINGTON, DC 20036-5274 USA SN 1529-6466 J9 REV MINERAL GEOCHEM PY 2000 VL 41 BP 211 EP 255 PG 45 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA BS78Q UT WOS:000171093200008 ER PT B AU Nesbitt, JA Barrett, CA Darolia, R AF Nesbitt, JA Barrett, CA Darolia, R BE McNallan, M Opila, E Maruyama, T Narita, T TI Cyclic oxidation of single-crystal NiAl-X alloys SO HIGH TEMPERATURE CORROSION AND MATERIALS CHEMISTRY SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Per Kofstad Memorial Symposium on High Temperature Corrosion and Materials Chemistry at the 1999 Joint Int Meeting of the Electrochem-Soc/Electrochem-Soc-of-Japan CY NOV, 1999 CL HONOLULU, HI SP Japan Soc Appl Phys, Electrochem Soc, Electrochem Soc Japan ID SCALES; MICROSTRUCTURE; ALPHA-AL2O3; MECHANISM; SIMS; ZR AB Several single-crystal NiAl-X alloys (X=Hf, Ti, Cr, Ga) were cyclically oxidized at 1100 degrees C for up to 1000 I-hr cycles. The alloys all showed protective, adherent alpha-Al2O3 scale formation with positive weight change behavior throughout the test. There was no clear correlation between the composition of the various alloys and the specific weight gain although the ranking by weight change was relatively consistent for two duplicate series of samples. The presence of Hf(0.5-0.8 at.%) resulted in the internal formation of Al2O3/HfO2 "stringers." Diffusion of Hf to the growing oxide stringers resulted in the development of a near-surface layer depleted of these precipitates. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Nesbitt, JA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 24 TC 0 Z9 0 U1 1 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-261-3 J9 ELEC SOC S PY 2000 VL 99 IS 38 BP 192 EP 203 PG 12 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA BQ40E UT WOS:000088255400017 ER PT B AU Opila, EJ Robinson, RC AF Opila, EJ Robinson, RC BE McNallan, M Opila, E Maruyama, T Narita, T TI The oxidation rate of SiC in high pressure water vapor environments SO HIGH TEMPERATURE CORROSION AND MATERIALS CHEMISTRY SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Per Kofstad Memorial Symposium on High Temperature Corrosion and Materials Chemistry at the 1999 Joint Int Meeting of the Electrochem-Soc/Electrochem-Soc-of-Japan CY NOV, 1999 CL HONOLULU, HI SP Japan Soc Appl Phys, Electrochem Soc, Electrochem Soc Japan ID SIO2 SCALE VOLATILITY; COMBUSTION CONDITIONS; SILICON-CARBIDE; MODEL AB CVD SiC and sintered alpha-SiC samples were exposed at 1316 degrees C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for SiC in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent nearly equal to one. Silica growth on SiC is therefore limited by transport of molecular water vapor through the silica scale. C1 Cleveland State Univ, NASA, Glenn Res Ctr, Dept Chem Engn, Cleveland, OH 44115 USA. RP Opila, EJ (reprint author), Cleveland State Univ, NASA, Glenn Res Ctr, Dept Chem Engn, Cleveland, OH 44115 USA. NR 11 TC 5 Z9 5 U1 1 U2 3 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-261-3 J9 ELEC SOC S PY 2000 VL 99 IS 38 BP 398 EP 406 PG 9 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA BQ40E UT WOS:000088255400036 ER PT B AU Lee, KN AF Lee, KN BE McNallan, M Opila, E Maruyama, T Narita, T TI Effects of impurities and coating design on the durability of EBC for silicon-base ceramics SO HIGH TEMPERATURE CORROSION AND MATERIALS CHEMISTRY SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT Per Kofstad Memorial Symposium on High Temperature Corrosion and Materials Chemistry at the 1999 Joint Int Meeting of the Electrochem-Soc/Electrochem-Soc-of-Japan CY NOV, 1999 CL HONOLULU, HI SP Japan Soc Appl Phys, Electrochem Soc, Electrochem Soc Japan ID SIC CERAMICS; WATER-VAPOR; WET OXYGEN; OXIDATION; CARBIDE C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lee, KN (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 15 TC 0 Z9 0 U1 0 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-261-3 J9 ELEC SOC S PY 2000 VL 99 IS 38 BP 417 EP 428 PG 12 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA BQ40E UT WOS:000088255400038 ER PT S AU Jacobson, NS Myers, DL Zhu, DM Humphrey, D AF Jacobson, NS Myers, DL Zhu, DM Humphrey, D BE Hilpert, K Froben, FW Singheiser, L TI Rhenium-oxygen interactions at high temperatures SO HIGH TEMPERATURE MATERIALS CHEMISTRY, PTS I AND II, PROCEEDINGS SE SCHRIFTEN DES FORSCHUNGSZENTRUMS JULICH REIHE ENERGIETECHNIK LA English DT Proceedings Paper CT 10th International Conference of the International-Union-of-Pure-and-Applied-Chemistry CY APR 10-14, 2000 CL RES CTR JULICH, JULICH, GERMANY SP Int Union Pure & Appl Chem HO RES CTR JULICH AB The reaction of pure rhenium metal with dilute oxygen/argon mixtures was studied from 600degrees to 1400degreesC. Temperature, oxygen pressure, and flow rates were systematically varied to determine the rate-controlling steps. At lower temperatures the oxygen/rhenium chemical reaction is rate limiting: at higher temperatures gas-phase diffusion of oxygen through the static boundary layer is rate limiting. At all temperatures post-reaction microstructures indicate preferential attack along certain crystallographic planes and defects. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Jacobson, NS (reprint author), NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU FORSCHUNGSZENTRUM JULICH GMBH PI JULICH PA CENT LIB, 52425 JULICH, GERMANY SN 1433-5522 BN 3-89336-277-0 J9 SCHR FZ JUL ENERG PY 2000 VL 15 BP 557 EP 560 PN 1 PG 4 WC Thermodynamics; Chemistry, Applied; Chemistry, Physical; Materials Science, Multidisciplinary SC Thermodynamics; Chemistry; Materials Science GA BU42W UT WOS:000175969300118 ER PT S AU Holt, SS AF Holt, SS BE Martens, PCH Tsuruta, S Weber, MA TI The next generation of high-energy astrophysics observatories SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID RAY AB The sky will soon be populated with a fleet of new X- and gamma-ray satellites with extraordinary capabilities. This paper is meant to introduce these new missions, Chandra, XMM, and Astro-E, which will provide a large fraction of our high energy "space observatory" functionality for the next decade. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Holt, SS (reprint author), NASA, Goddard Space Flight Ctr, Code 600, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 5 EP 13 PG 9 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200001 ER PT S AU Swank, J AF Swank, J BE Martens, PCH Tsuruta, S Weber, MA TI Recent observations of X-ray emission from galactic binary neutron stars SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MT SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID QUASI-PERIODIC OSCILLATIONS; BRIGHTNESS OSCILLATIONS; SPECTRUM; BURSTS; 4U-1728-34; FREQUENCY; FEATURES; PULSAR AB Recent measurements of young, accreting binary neutron stars are determining more precise magnetic field and accretion parameters. A low magnetic field, accreting, millisecond pulsar has finally been found in a binary burster. At least 20 low-mass binaries have exhibited high frequency oscillations, 300-1200 hertz. The majority have, for some range of luminosity, the pair of quasiperiodic oscillations that have never been seen in a black hole candidate. Recent evidence from burst oscillations strengthens the case that the difference frequency of this pair is close to the spin frequency of the neutron star. These oscillations are correlated with the spectra, luminosity, and low frequency oscillations. Quasiperiodic oscillations are also seen sometimes in strong magnetic field pulsars, where their origin can be closely examined. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM swank@pcasun1.gsfc.nasa.gov NR 26 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 27 EP 36 PG 10 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200003 ER PT S AU White, NE Tananbaum, H AF White, NE Tananbaum, H BE Martens, PCH Tsuruta, S Weber, MA TI The Constellation X-ray mission SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN AB The Constellation-X mission is a large collecting-area X-ray facility emphasizing observations at high spectral resolution (E/DeltaE similar to 300-3000) while covering a broad energy band (0.25-40 keV). By increasing the telescope aperture and utilizing efficient spectrometers, the mission will achieve a factor of 100 increased sensitivity over current high-resolution X-ray spectroscopy missions. The use of focusing optics across the 10-40 keV band will provide a similar factor of 100 increased sensitivity in this band. When observations commence in similar to 2008, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP White, NE (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012 OI White, Nicholas/0000-0003-3853-3462 NR 9 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 61 EP 68 PG 8 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200006 ER PT S AU Petre, R Allen, GE Hwang, U Keohane, JW Gotthelf, EV AF Petre, R Allen, GE Hwang, U Keohane, JW Gotthelf, EV BE Martens, PCH Tsuruta, S Weber, MA TI X-ray emission as an indicator of cosmic ray acceleration in supernova remnants SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID SN-1006; ELECTRONS; DISCOVERY; SHELL; TEV AB X-ray observations over the past several years have led to the discovery of nonthermal X-ray emission arising in the shells of many young supernova remnants, including SN 1006, Cas A, and Tycho. This emission is thought to be synchrotron emission from electrons that have been shock accelerated to hundreds of TeV, and thus represents strong evidence that cosmic rays are accelerated in SNR shocks. The X-ray observations are corroborated by detection of TeV gamma rays from two of these remnants. A systematic investigation of young, shell-like remnants suggests that the nonthermal X-ray emission from shock-accelerated electrons is a common, if not ubiquitous, feature. We review the status of the X-ray observations and describe how they can be used to provide insight into the shock acceleration process. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. MIT, NASA, Chandra Xray Ctr, Cambridge, MA 02139 USA. Univ Maryland, Greenbelt, MD 20771 USA. N Carolina Sch Sci & Math, NASA, Durham, NC 27705 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. RP Petre, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 69 EP 76 PG 8 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200007 ER PT S AU Ramaty, R Mandzhavidze, N AF Ramaty, R Mandzhavidze, N BE Martens, PCH Tsuruta, S Weber, MA TI Gamma-rays from solar flares SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID ABUNDANCES; SPECTROSCOPY; PARTICLES; ACCELERATION; EMISSIONS; SPECTRA AB Gamma-ray emission is the most direct diagnostic of energetic ions and relativistic electrons in solar flares. Analysis of solar flare gamma-ray data has shown: (i) ion acceleration is a major consequence of flare energy release, as the total flare energy in accelerated particles appears to be equipartitioned between greater than or similar to 1 MeV/nucleon ions and greater than or similar to 20 keV electrons, and amounts to an important fraction of the total energy release; (ii) there are flares for which over 50% of the energy is in a particles and heavier ions; (iii) in both impulsive and gradual flares, the particles that interact at the Sun and produce gamma rays are essentially always accelerated by the same mechanism that operates in impulsive flares, probably stochastic acceleration through gyroresonant wave particle interaction; and (iv) gamma-ray spectroscopy can provide new information on solar abundances, for example the site of the FIP-bias onset and the photospheric He-3 abundance. We propose a new technique for the investigation of mass motion and mixing in the solar atmosphere: the observations of gamma-ray lines from long-term radioactivity produced by flare accelerated particles. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USRA, Greenbelt, MD 20771 USA. RP Ramaty, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 40 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 123 EP 132 PG 10 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200013 ER PT S AU O'Neill, P Sood, R Durouchoux, P Safi-Harb, S AF O'Neill, P Sood, R Durouchoux, P Safi-Harb, S BE Martens, PCH Tsuruta, S Weber, MA TI Interaction of the SS433 Jet with the interstellar medium SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID SS-433 AB X-ray emission observed from the SS433/W50 system has been interpreted as resulting from the interaction of the binary jets with the surrounding medium. We have been carrying out millimetre wavelength measurements of this system. We find no evidence for the association of a molecular cloud with the eastern jet, but we do find evidence for a strong association with the western jet. C1 Univ New S Wales, Univ Coll, Australian Def Force Acad, Sch Phys, Canberra, ACT 2600, Australia. GSFC, NASA, Greenbelt, MD 20771 USA. RP O'Neill, P (reprint author), Univ New S Wales, Univ Coll, Australian Def Force Acad, Sch Phys, Canberra, ACT 2600, Australia. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 419 EP 420 PG 2 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200064 ER PT S AU Sankrit, R Blair, WP AF Sankrit, R Blair, WP CA FUSE SNR Team BE Martens, PCH Tsuruta, S Weber, MA TI Far-ultraviolet emission from supernova remnant shocks SO HIGHLY ENERGETIC PHYSICAL PROCESSES AND MECHANISMS FOR EMISSION FROM ASTROPHYSICAL PLASMAS SE IAU SYMPOSIA LA English DT Article; Proceedings Paper CT 195th Symposium of the International-Astronomical-Union CY JUL 06-10, 1999 CL MONTANA STATE UNIV BOZEMAN, BOZEMAN, MONTANA SP Int Astron Union, NASA, NSF HO MONTANA STATE UNIV BOZEMAN ID CYGNUS-LOOP AB Supernova remnant shocks produce a rich spectrum of lines in the ultraviolet. Among these are important diagnostic resonance lines of O VI, C III, and N III which the in the bandpass observable with the recently launched Far Ultraviolet Spectroscopic Explorer. We present an overview of a PI program to observe several supernova remnants using this new telescope. C1 Johns Hopkins Univ, Baltimore, MD 21218 USA. UC Berkeley, IAP, GSFC, JHU, Princeton, NJ USA. RP Sankrit, R (reprint author), Johns Hopkins Univ, 3400 N Charles St, Baltimore, MD 21218 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0074-1809 BN 1-58381-038-2 J9 IAU SYMP PY 2000 IS 195 BP 425 EP 426 PG 2 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BU35P UT WOS:000175748200067 ER PT S AU McIlraith, S Biswas, G Clancy, D Gupta, V AF McIlraith, S Biswas, G Clancy, D Gupta, V BE Lynch, N Krogh, BH TI Hybrid systems diagnosis SO HYBRID SYSTEMS: COMPUTATION AND CONTROL SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 3rd International Workshop on Hybrid Systems: Computation and Control CY MAR 23-25, 2000 CL PITTSBURGH, PENNSYLVANIA SP Air Force Off Sci Res, IEEE Control Syst Soc, Ford Motor Co, Natl Sci Fdn, Dept Electr & Comp Eng, Dept Electr Eng & Comp Sci AB This paper reports on an on-going project to investigate techniques to diagnose complex dynamical systems that are modeled as hybrid systems. In particular, we examine continuous systems with embedded supervisory controllers that experience abrupt, partial or full failure of component devices. We cast the diagnosis problem as a model selection problem. To reduce the space of potential models under consideration, we exploit techniques from qualitative reasoning to conjecture an initial set of qualitative candidate diagnoses, which induce a smaller set of models. We refine these diagnoses using parameter estimation and model fitting techniques. As a motivating case study, we have examined the problem of diagnosing NASA's Sprint AERCam, a small spherical robotic camera unit with 12 thrusters that enable both linear and rotational motion. C1 Stanford Univ, Knowledge Syst Lab, Stanford, CA 94305 USA. Vanderbilt Univ, Dept Comp Sci, Nashville, TN 37212 USA. NASA, Ames Res Ctr, Caelum Res Corp, Moffett Field, CA 94035 USA. RP McIlraith, S (reprint author), Stanford Univ, Knowledge Syst Lab, Stanford, CA 94305 USA. NR 25 TC 33 Z9 34 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-67259-1 J9 LECT NOTES COMPUT SC PY 2000 VL 1790 BP 282 EP 295 PG 14 WC Automation & Control Systems; Computer Science, Theory & Methods SC Automation & Control Systems; Computer Science GA BQ47V UT WOS:000088438200025 ER PT S AU Major, GR AF Major, GR BE Markham, JW Duda, AL TI NASA's Global Change Master Directory: Fostering collaborations for earth science information and data retrieval SO IAMSLIC 99: RECASTING THE NETS SE INTERNATIONAL ASSOCIATION OF AQUATIC AND MARINE SCIENCE, LIBRARIES AND INFORMATION CONFERENCE SERIES LA English DT Proceedings Paper CT 25th Annual Conference of the International-Association-of-Aquatic-and-Marine-Science-Libraries-and-In formation-Centers CY OCT 16-22, 1999 CL WOODS HOLE, MA SP Int Assoc Aquat & Marine Sci Lib Informat Ctr C1 Raytheon ITSS, NASA, Global Change Master Directory, Lanham, MD 20706 USA. RP Major, GR (reprint author), Raytheon ITSS, NASA, Global Change Master Directory, 4500 Forbes Blvd Suite 300, Lanham, MD 20706 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU INT ASSOC MARINE SCIENCE LIBRARIES & INFORMATION CENTER PI FORT PIERCE PA C/O HBOI LIBRARY, 5600 OLD DIXIE HWY, FORT PIERCE, FL 34946 USA SN 8755-6332 J9 IAMSLIC C S PY 2000 BP 119 EP 124 PG 4 WC Computer Science, Interdisciplinary Applications; Information Science & Library Science; Marine & Freshwater Biology SC Computer Science; Information Science & Library Science; Marine & Freshwater Biology GA BQ36Q UT WOS:000088143000014 ER PT J AU Mannings, V Boss, A Russell, S AF Mannings, V Boss, A Russell, S TI Protostars and Planets IV SO ICARUS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Carnegie Inst Washington, Washington, DC 20005 USA. Museum Nat Hist, London, England. RP Mannings, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2000 VL 143 IS 1 BP 1 EP 1 DI 10.1006/icar.1999.6299 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281TD UT WOS:000085176100001 ER PT J AU Bodenheimer, P Hubickyj, O Lissauer, JJ AF Bodenheimer, P Hubickyj, O Lissauer, JJ TI Models of the in situ formation of detected extrasolar giant planets SO ICARUS LA English DT Article; Proceedings Paper CT Protostars and Planets IV Conference (PPIV) CY JUL, 1998 CL SANTA BARBARA, CA DE origin of planetary systems; jovian planets, formation; jovian planets, interiors; accretion; extrasolar planets ID BROWN DWARF; SOLAR NEBULA; PROTOPLANETARY DISKS; ORBITAL MIGRATION; TIDAL INTERACTION; ACCRETION DISKS; MASS; EVOLUTION; COMPANION; SYSTEMS AB We present numerical simulations of the formation of the planetary companions to 47 UMa, rho CrB, and 51 Peg. They are assumed to have formed in situ according to the basic model that a core formed first by accretion of solid particles, then later it captured substantial amounts of gas from the protoplanetary disk. In most of the calculations we prescribe a constant accretion rate for the solid core. The evolution of the gaseous envelope is calculated according to the following assumptions: (1) it is in quasi-hydrostatic equilibrium, (2) the gas accretion rate is determined by the requirement that the outer radius of the planet is the place at which the thermal velocity of the gas allows it to reach the boundary of the planet's Hill sphere, (3) the gas accretion rate is limited, moreover, by the prescribed maximum rate at which the nebula can supply the gas, and (4) the growth of the planet stops once it obtains approximately the minimum mass determined from radial velocity measurements (in one case the planet is allowed to grow to twice this limit). Calculations are carried out through an initial phase during which solid accretion dominates, past the point of crossover when the masses of solid and gaseous material are equal, through the phase of rapid gas accretion, and into the final phase of contraction and cooling at constant mass. Alternative calculations are presented for the case of 47 UMa in which the solid accretion rate is calculated, not assumed, and the dissolution of planetesimals within the gaseous envelope is considered. In all cases there is a short phase of high luminosity (10(-3)-10(-2) L.) associated with rapid gas accretion. The height and duration of this peak depend on uncertain model parameters. The conclusion is reached that in situ formation of all of these companions is possible under some conditions. However, it is more likely that orbital migration was an important component of the evolution, at least for the planets around rho CrB and 51 Peg. (C) 2000 Academic Press. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Bodenheimer, P (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. EM peter@ucolick.org NR 76 TC 177 Z9 178 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2000 VL 143 IS 1 BP 2 EP 14 DI 10.1006/icar.1999.6246 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281TD UT WOS:000085176100002 ER PT J AU Desch, SJ Cuzzi, JN AF Desch, SJ Cuzzi, JN TI The generation of lightning in the solar nebula SO ICARUS LA English DT Article; Proceedings Paper CT Protostars and Planets IV Conference (PPIV) CY JUL, 1998 CL SANTA BARBARA, CA DE chondrules; dust; meteorites; origin, Solar System; solar nebula; lightning; turbulence ID DENSE INTERSTELLAR CLOUDS; SHOCK-WAVE MODEL; CHONDRULE FORMATION; PREFERENTIAL CONCENTRATION; PROTOPLANETARY NEBULA; ORDINARY CHONDRITES; PROTOSOLAR NEBULA; ACCRETION DISKS; TURBULENCE; PARTICLES AB The process that melted and formed the chondrules, millimeter-sized glassy beads within meteorites, has not been conclusively identified. Origin by lightning in the solar nebula is consistent with many features of chondrules, but no viable model of lightning has yet been advanced. We present a model demonstrating how lightning could be generated in the solar nebula which differs from previous models in two important aspects. First, we identify a new, powerful charging mechanism that is based on the differences in contact potentials between particles of different composition, a form of triboelectric charging. In the presence of fine silicate grains and fine iron metal grains, large silicate particles (the chondrules) can acquire charges greater than or similar to +10(5) e. Second, we assume that the chondrule precursor particles are selectively concentrated in clumps similar to 100 km in size by the turbulent concentration mechanism described by J. N. Cuzzi et al. (1996, in Chondrules and the Protoplanetary Disk, pp. 35-43, Cambridge Univ. Press). The concentration of these highly charged particles into clumps, in a background of negatively charged metal grains, is what generates the strong electric fields. We calculate that electric fields large enough to trigger breakdown easily could have existed over regions large enough (similar to 100 km) to generate very large discharges of electrical energy (similar to 10(16) erg), assuming a lightning bolt width 10 electron mean-free paths. The discharges would have been sufficiently energetic to have formed the chondrules. We place constraints on the generation of lightning and conclude that it could not be generated if the abundance of (26)Al in chondrules was as high as the level in the calcium-aluminumrich inclusions (CAIs). This conclusion is consistent with isotopic analyses of chondrules. This possibly implies that (26)Al was nonuniformly distributed in the solar nebula or that the chondrules formed several million years after the CAIs. (C) 2000 Academic Press. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Desch, SJ (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM desch@cosmic.arc.nasa.gov NR 94 TC 106 Z9 106 U1 1 U2 14 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2000 VL 143 IS 1 BP 87 EP 105 DI 10.1006/icar.1999.6245 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281TD UT WOS:000085176100008 ER PT J AU Wooden, DH Butner, HM Harker, DE Woodward, CE AF Wooden, DH Butner, HM Harker, DE Woodward, CE TI Mg-rich silicate crystals in comet Hale-Bopp: ISM relics or solar nebula condensates? SO ICARUS LA English DT Article; Proceedings Paper CT Protostars and Planets IV Conference (PPIV) CY JUL, 1998 CL SANTA BARBARA, CA DE comets, Hale-Bopp; infrared observations, interplanetary dust; mineralogy; planetesimals ID INTERPLANETARY DUST PARTICLES; INFRARED TRANSMISSION SPECTRA; INTERSTELLAR DUST; ISOTOPIC MEASUREMENTS; IRRADIATED GRAINS; FAYALITIC OLIVINE; C/1995 O1; MINERALOGY; PYROXENE; STARS AB We compare the HIFOGS 10-mu m spectra of Comet C/1995 (O1) (Hale-Bopp) to the mid-LR spectra of interplanetary dust particles (IDPs), The four epochs of Hale-Bopp silicate features, at 2.8 AU (pre-perihelion), 1.2 AU (pre-perihelion), 0.93 AU (10 days after perihelion), and 1.7 AU (post-perihelion) have different spectral shapes. At smaller heliocentric distances, r(h) less than or equal to 1.7 AU, there appears to be enhanced mid-IR emission (i.e., 9.3- and 10.5-mu m peaks) from Mg-rich pyroxene crystals. A two-temperature model of warm amorphous and crystalline olivines, warm amorphous pyroxenes, and similar to 165 K cooler pyroxene crystals is successful with laboratory silicate minerals (D. H. Wooden et al. 1999, Astrophys. J. 517, 1034-1058). A two-temperature model using LDPs as cometary dust particle analogs also fits Comet Hale-Bopp's silicate features, with the pyroxene IDP similar to 50 K cooler than the olivine and layer-lattice silicate IDPs. The warm layer-lattice silicate IDP contributes a broad 20-mu m feature which is not in the Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) spectrum of Hale-Bopp at 2.8 AU, making it a questionable cometary component. On the other hand, members of the "cluster IDP" subclass of pyroxene IDPs fit Hale-Bopp's 10-mu m spectra better than other pyroxene IDPs. Cluster IDPs are highly fragile and contain significant deuterium enrichments, indicating their presolar origin. By spectroscopic analogy, Comet Hale-Bopp's Mg-rich pyroxene crystals may also be relic interstellar grains. The IDP and mineral models for Comet Hale-Bopp indicate the importance of multiple grain components at different temperatures to explaining the temporal evolution of the observed infrared features. Relative abundances of minerals depend on their relative temperatures. Cooler grains may be more abundant than warmer grains and yet may remain hidden from detection in the 10-mu m silicate feature because of their cooler temperatures. The deduced larger abundance of cooler, pyroxene-dominated grains in Comet Hale-Bopp affects the interpretation of the origin of cometary dust, and dust evolution during protoplanetesimal accumulation and disk dissipation. (C) 2000 Academic Press. C1 NASA, Ames Res Ctr, Planetary Syst Branch, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ SMTO, Tucson, AZ 85721 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. RP Wooden, DH (reprint author), NASA, Ames Res Ctr, Planetary Syst Branch, MS 245-3, Moffett Field, CA 94035 USA. EM wooden@delphinus.arc.nasa.gov OI Harker, David/0000-0001-6397-9082; Butner, Harold/0000-0003-4899-2064 NR 77 TC 60 Z9 60 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD JAN PY 2000 VL 143 IS 1 BP 126 EP 137 DI 10.1006/icar.1999.6240 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281TD UT WOS:000085176100010 ER PT J AU Greaves, JS Mannings, V Holland, WS AF Greaves, JS Mannings, V Holland, WS TI The dust and gas content of a disk around the young star HR 4796A SO ICARUS LA English DT Article; Proceedings Paper CT Protostars and Planets IV Conference (PPIV) CY JUL, 1998 CL SANTA BARBARA, CALIFORNIA DE planets; formation; extraterrestrial planets ID MILLIMETER-WAVE PROPERTIES; VEGA-LIKE SYSTEMS; PHOTODISSOCIATION; DEPLETION; EMISSION; DEBRIS; CO AB We have used the James Clerk Maxwell Telescope in Hawaii to search at submillimeter wavelengths for continuum emission from dust, and spectral line emission from carbon monoxide (CO) gas, in the neighborhood of HR 4796A, This young star has a dusty disk with a central cavity, where planets may have formed, We detect the dust component at a wavelength of 850 mu m, and the inferred mass of solid material is greater than or equal to 0,25 M+. An upper limit for the CO J = 3-2 rotational line implies less than 1-7 M+ (less than or equal to 0.003-0.002 Jupiter masses) of molecular H-2 gas in the system. Thus, it is no longer possible to form new Jupiter-like gaseous giant planets around HR 4796A, If planet formation explains the observed dust cavity and lack of gas, then it must have occurred before the current stellar age of similar to 10 Myr. A search was also made for CO J = 3-2 emission around four other stars with dust excesses revealed by infrared measurements with the Infrared Astronomical Satellite (IRAS), Two were detected, both of them young sources with optical emission lines indicative of ongoing accretion of disk material onto the star, The gas mass lower limits are approximately 30 and 200 Earth masses, at least an order of magnitude higher than that for HR 4796A, illustrating the diversity of disk properties at ages of up to 10 Myr. (C) 2000 Academic Press. C1 Joint Astron Ctr, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Greaves, JS (reprint author), Joint Astron Ctr, 660 N Aohoku Pl, Hilo, HI 96720 USA. NR 23 TC 51 Z9 51 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JAN PY 2000 VL 143 IS 1 BP 155 EP 158 DI 10.1006/icar.1999.6244 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 281TD UT WOS:000085176100013 ER PT S AU Ye, Z Seyedi, A Saulnier, GJ Medley, MJ AF Ye, Z Seyedi, A Saulnier, GJ Medley, MJ GP IEEE IEEE TI Processing gain variation vs. power control in CDMA packet radio networks SO ICC 2000: IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, CONFERENCE RECORD, VOLS 1-3: GLOBAL CONVERGENCE THROUGH COMMUNICATIONS SE IEEE International Conference on Communications LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC 2000) CY JUN 18-22, 2000 CL NEW ORLEANS, LA SP IEEE Commun Soc, ICC Globecom, IEEE Networking World AB In this paper, we investigate the effect of varying the processing gain in place of power control in a CDMA packet radio network, The classic CDMA protocol is modified to accommodate the variable processing gain, allowing for variable packet durations due to variable processing gain. The performance of the variable processing gain system is measured in terms of the network throughput and is compared to the performance of conventional fixed rate CDMA systems in which perfect power control is assumed. Results are first generated for a terrestrial CDMA network and extended to a Low Earth Orbit Satellite (LEOS) communication topology. In the interference limited CDMA network, we have demonstrated that processing gain control can be used in place of power control and, depending on the details of the implementation, can achieve the same or nearly the same throughput performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ye, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1550-3607 BN 0-7803-6283-7 J9 IEEE ICC PY 2000 BP 758 EP 762 PG 5 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BQ63J UT WOS:000089018200149 ER PT B AU Gilliam, DP Kelly, JC Bishop, M AF Gilliam, DP Kelly, JC Bishop, M GP IEEE IEEE TI Reducing software security risk through an integrated approach SO IEEE 9TH INTERNATIONAL WORKSHOPS ON ENABLING TECHNOLOGIES: INFRASTRUCTURE FOR COLLABORATIVE ENTERPRISES, PROCEEDINGS LA English DT Proceedings Paper CT 9th IEEE International Workshops on Enabling Technologies - Infrastructure for Collaborative Enterprises (WET ICE 2000) CY JUN 14-16, 2000 CL NATL INST STAND & TECHNOL, GAITHERSBURG, MD SP IEEE Comp Soc, W Virginia Univ, Concurrent Engn Res Ctr, Linkoping Univ, Sweden HO NATL INST STAND & TECHNOL DE security toolset; vulnerability matrix; property-based testing; model specification checking; security verification AB This paper discusses new joint work by the California Institute of Technology's Jet Propulsion Laboratory and the University of California at Davis sponsored by the national Aeronautics and Space Administration to develop a security assessment instrument for the software development and maintenance life cycle. The assessment instrument is a collection of tools and procedures to support development of secure software. The toolset initially will have a Vulnerability Matrix (VMatrix) with severity, frequency, platform/application, and signature field in a database keyed on the Computer Vulnerability Enumeration (CVE) number. The toolset also will include a property-based testing tool to slice software code looking for specific vulnerabilities using signatures from the VMatrix. A third component of the research underlying this toolset will be an investigation not the verification of software design for compliance to security properties. This is based on model checking approaches initially researched together wit analytical verification of formal specification. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gilliam, DP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-0798-0 PY 2000 BP 141 EP 146 PG 6 WC Computer Science, Interdisciplinary Applications SC Computer Science GA BQ99P UT WOS:000165310400023 ER PT J AU Landis, GA AF Landis, GA TI Solar cell selection for Mars SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB The surface of Mars is an environment significantly different from both the surface of the Earth and from orbit. Solar cell performance is the major constraint on the landing site latitude, on science operations, and on how long during each day and during which Mars seasons a spacecraft can operate. This article examines what we know about the environment of Mars and how it affects the selection of solar cells for Mars surface operation. C1 NASA, John Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, John Glenn Res Ctr, Ohio Aerosp Inst, Mailstop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 4 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD JAN PY 2000 VL 15 IS 1 BP 17 EP 21 DI 10.1109/62.821659 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 285EM UT WOS:000085376800004 ER PT B AU Simons, RN AF Simons, RN GP IEEE IEEE IEEE TI Suspended patch antennas with electromagnetically coupled inverted microstrip feed for circular polarization SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co ID TRANSMISSION-LINES AB The paper demonstrates a suspended nearly square patch antenna with offset feed and a square patch antenna with truncated corners for circular polarization. The antennas are excited by an electromagnetically coupled inverted microstrip iced. In addition a new transition between conventional microstrip and inverted microstrip is proposed. The measured results include the axial ratio and the impedance bandwidth of the antennas. C1 NASA, Glenn Res Ctr, Dynacs Engn Co Inc, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Glenn Res Ctr, Dynacs Engn Co Inc, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 992 EP 995 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900242 ER PT B AU Pogorzelski, RJ AF Pogorzelski, RJ GP IEEE IEEE IEEE TI On a simple method of obtaining sidelobe reduction over a wide angular range in one and two dimensions SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co ID ARRAYS C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pogorzelski, RJ (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 IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 1214 EP 1217 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900295 ER PT B AU Huang, J Feria, A Lopez, B Lou, M AF Huang, J Feria, A Lopez, B Lou, M GP IEEE IEEE IEEE TI Deployable and light-weight array antennas for space application SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Huang, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 1244 EP 1244 PG 1 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900307 ER PT B AU Imbriale, WA Hoppe, DJ AF Imbriale, WA Hoppe, DJ GP IEEE IEEE IEEE TI Computational techniques for beam waveguide systems SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Imbriale, WA (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 IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 1894 EP 1897 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900468 ER PT B AU Simons, RN AF Simons, RN GP IEEE IEEE IEEE TI Suspended rectangular/circular patch antennas with electromagnetically coupled inverted microstrip feed for dual polarization/frequency SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co ID TRANSMISSION-LINES AB The paper demonstrates suspended rectangular and circular patch antennas with eletromagnetically coupled inverted microstrip feed for linear as well as dual linear polarization/frequency applications. The measured results include the return loss and the impedance bandwidth or the antennas. C1 NASA, Glenn Res Ctr, Dynacs Engn Co Inc, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Glenn Res Ctr, Dynacs Engn Co Inc, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 2204 EP 2207 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900540 ER PT B AU Ponchak, GE Simons, RN Scardelletti, M Varaljay, NC AF Ponchak, GE Simons, RN Scardelletti, M Varaljay, NC GP IEEE IEEE IEEE TI Microelectromechanical switches for phased array antennas SO IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-4: TRANSMITTING WAVES OF PROGRESS TO THE NEXT MILLENNIUM LA English DT Proceedings Paper CT 2000 IEEE Antennas-and-Propagation-Society International Symposium CY JUL 16-21, 2000 CL SALT LAKE CITY, UT SP IEEE, Antennas & Propagat Soc, Agilent Technol, Hewlett Packard Co, Kennecott Utah Copper, L 3 Commun, Moog Inc, Motorola, Raytheon Syst Co AB Preliminary results are presented on the fabrication and testing of a Micro-Electro-Mechanical (MEM) microstrip series switch. This switch is being developed for use in a K-band phased array antenna that NASA will use for communication links in its Earth orbiting satellites. Preliminary insertion loss and isolation measurements are presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-6370-1 PY 2000 BP 2230 EP 2233 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BQ87W UT WOS:000089912900546 ER PT J AU Ko, YC Alouini, MS Simon, MK AF Ko, YC Alouini, MS Simon, MK TI Average SNR of dual selection combining over correlated Nakagami-m fading channels SO IEEE COMMUNICATIONS LETTERS LA English DT Article DE fading correlation; Nakagami fading; selection combining ID PERFORMANCE AB We investigate the effect of fading correlation and branch gain imbalance on the average output signal-to-noise ratio (SNR) in conjunction with dual selection combining (SC), In particular, starting with the moment generating function of the dual SC output SNR, we derive a closed-form expression for the average output SNR in the general case of correlated unbalanced Nakagami-m fading channels. We then show that the generic result can be further simplified for the special cases of Rayleigh fading, uncorrelated branches, and/or equal average SMR's, Because of their simple form, the given expressions readily allow numerical evaluation for cases of practical interest. C1 Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ko, YC (reprint author), Univ Minnesota, Dept Elect & Comp Engn, Minneapolis, MN 55455 USA. NR 14 TC 42 Z9 42 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1089-7798 J9 IEEE COMMUN LETT JI IEEE Commun. Lett. PD JAN PY 2000 VL 4 IS 1 BP 12 EP 14 DI 10.1109/4234.823534 PG 3 WC Telecommunications SC Telecommunications GA 283XJ UT WOS:000085301100005 ER PT S AU Manduchi, R AF Manduchi, R GP IEEE IEEE IEEE TI Mixture models and the segmentation of multimodal textures SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL I SE IEEE Conference on Computer Vision and Pattern Recognition LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence ID IMAGE AB A problem with using nature-of-Gaussian models for unsupervised texture segmentation is that a "multimodal" lecture (such as can often be encountered in natural images) cannot be well represented by a single Gaussian cluster. We propose a divide-and-conquer method that groups together Gaussian clusters (Estimated via Expectation Maximization) into homogeneous texture classes. This method allows to succesfully segment even rather complex textures, as demonstrated by experimental tests on natural images. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM manduchi@jpl.nasa.gov NR 16 TC 2 Z9 4 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-7695-0662-3 J9 PROC CVPR IEEE PY 2000 BP 98 EP 104 PG 7 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57F UT WOS:000088804500015 ER PT S AU Smelyanskiy, VN Cheeseman, P Maluf, DA Morris, RD AF Smelyanskiy, VN Cheeseman, P Maluf, DA Morris, RD GP IEEE IEEE IEEE TI Bayesian super-resolved surface reconstruction from images SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL I SE IEEE Conference on Computer Vision and Pattern Recognition LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB Bayesian inference has been used successfully for many problems where the aim is to infer the parameters of a model of interest. In this paper we formulate the three dimensional reconstruction problem as the problem of inferring the parameters of a surface model from image data, and show how Bayesian methods can be used to estimate the parameters of this model given the image data. Thus we recover the three dimensional description of the scene. This approach also gives great flexibility. We can specify the geometrical properties of the model to suit our purpose, and can also use different models for how the surface reflects the light incident upon, it. In common with other Bayesian inference problems, the estimation methodology requires that we can simulate the data that would have been recorded for any values of the model parameters. In this application this means that if we have image data we must be able to render the surface model. However it also means that we can infer the parameters of a model whose resolution can be chosen irrespective of the resolution of the images, and may be super-resolved We present results of the inference of surface models from simulated aerial photographs for the case of super-resolution, where many surface elements project into a single pixel in the low-resolution images. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM vadim@ptolemy.arc.nasa.gov; cheesem@ptolemy.arc.nasa.gov; maluf@ptolemy.arc.nasa.gov; rdm@ptolemy.arc.nasa.gov NR 8 TC 5 Z9 7 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-7695-0662-3 J9 PROC CVPR IEEE PY 2000 BP 375 EP 382 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57F UT WOS:000088804500053 ER PT S AU DeCoste, D Burl, MC AF DeCoste, D Burl, MC GP IEEE IEEE IEEE TI Distortion-invariant recognition via jittered queries SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL I SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB This paper presents a new approach for achieving distortion-invariant recognition and classification. A test example to be classified is viewed as a query intended to find similar examples in the training set (or to find similar class models that represent a compression of the training set). The key idea is that instead of querying with a single pattern, we construct a more robust query, based on the family of patterns formed by distorting the test example. Although query execution is slower than if the invariances were successfully precompiled during training, there are significant advantages in several contests: (i) providing invariances in memory-based learning, (ii) in model selection, where reducing training time at the expense of test time is a desirable trade-off and (iii) in enabling robust, ad hoc searches based on a single example. Preliminary tests for memory-based learning on the NIST handwritten digit database with a limited set of shearing and translation distortions produced an error rate of 1.35%. C1 CALTECH, Jet Prop Lab, Machine Learing Syst Grp, Pasadena, CA 91109 USA. RP DeCoste, D (reprint author), CALTECH, Jet Prop Lab, Machine Learing Syst Grp, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 BN 0-7695-0662-3 J9 PROC CVPR IEEE PY 2000 BP 732 EP 737 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57F UT WOS:000088804500103 ER PT S AU Olson, CF AF Olson, CF GP IEEE IEEE TI Maximum-likelihood template matching SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL II SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence AB In image matching applications such as tracking and stereo matching, it is common to use the sum-of-squared-differences (SSD) measure to determine the best match for an image template. However, this measure is sensitive to outliers and is not robust to template variations. We describe a robust measure and efficient search strategy for template matching with a binary or greyscale template using a maximum-likelihood formulation. In addition to subpixel localization and uncertainty estimation, these techniques allow optimal feature selection based on minimizing the localization uncertainty. We examine the use of these techniques for object recognition, stereo matching, feature selection, and tracking. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 125-209, Pasadena, CA 91109 USA. NR 8 TC 8 Z9 16 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 J9 PROC CVPR IEEE PY 2000 BP 52 EP 57 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57E UT WOS:000088804400007 ER PT S AU Johnson, AE AF Johnson, AE GP IEEE IEEE TI Surface landmark selection and matching in natural terrain SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL II SE IEEE Conference on Computer Vision and Pattern Recognition LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence ID OBJECT RECOGNITION; SCENES AB In this paper we present an algorithm for robust absolute position estimation in natural terrain based on landmarks extracted from dense 3-D surfaces. Our landmarks are constructed by concatenating pose dependent oriented surface points with pose invariant surface signatures into a single feature vector; this definition of landmarks allows a priori pose information to be used to constrain the search for landmark matches. The first step in our algorithm is to extract landmarks from stable and salient surface patches. These landmarks are then stored in a closest point search structure with which landmarks are matched efficiently using available pose constraints and invariant values. Finally, an iterative pose estimation algorithm, based on least median squares, is wrapped around landmark matching to eliminate outliers and estimate absolute position. To validate our algorithm, we show hundreds of absolute position estimation results from three different natural scenes. These results short that our algorithm can incorporate constraints on position and attitude for efficient landmark matching and match small and dense scene surface parches to large and coarse model surfaces. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 125-209,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 15 Z9 20 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 J9 PROC CVPR IEEE PY 2000 BP 413 EP 420 PG 8 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57E UT WOS:000088804400055 ER PT S AU Olson, CF Matthies, LH Schoppers, M Maimone, MV AF Olson, CF Matthies, LH Schoppers, M Maimone, MV GP IEEE IEEE TI Robust stereo ego-motion for long distance navigation SO IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION, PROCEEDINGS, VOL II SE PROCEEDINGS - IEEE COMPUTER SOCIETY CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION LA English DT Proceedings Paper CT IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2000) CY JUN 13-15, 2000 CL HILTON HEAD ISL, SC SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Pattern Anal & Machine Intelligence ID 3-D AB Several methods for computing observer motion from monocular and stereo image sequences have been proposed. However, accurate positioning over long distances requires a higher level of robustness than previously achieved. This paper describes several mechanisms for improving robustness in the context of a maximum-likelihood stereo ego-motion method. We demonstrate that even a robust system will accumulate super-linear error in the distance traveled due to increasing orientation. errors. However, when an. absolute orientation sensor is incorporated, the error growth is reduced to linear in the distance traveled, and grows much more slowly in practice. Our experiments, including a trial with 210 stereo pairs, indicate that these techniques can achieve errors below 1% of the distance traveled. This method has been implemented to run on-board a prototype Mass rover. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Olson, CF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 23 Z9 25 U1 0 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1063-6919 J9 PROC CVPR IEEE PY 2000 BP 453 EP 458 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BQ57E UT WOS:000088804400060 ER PT J AU Filman, R AF Filman, R TI 2020 Hindsight SO IEEE INTERNET COMPUTING LA English DT Editorial Material C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. RP Filman, R (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1089-7801 J9 IEEE INTERNET COMPUT JI IEEE Internet Comput. PD JAN-FEB PY 2000 VL 4 IS 1 BP 79 EP 82 PG 4 WC Computer Science, Software Engineering SC Computer Science GA 272TW UT WOS:000084667900029 ER PT J AU Jabbour, GE Shaheen, SE Morrell, MM Anderson, JD Lee, P Thayumanavan, S Barlow, S Bellmann, E Grubbs, RH Kippelen, B Marder, S Armstrong, NR Peyghambarian, N AF Jabbour, GE Shaheen, SE Morrell, MM Anderson, JD Lee, P Thayumanavan, S Barlow, S Bellmann, E Grubbs, RH Kippelen, B Marder, S Armstrong, NR Peyghambarian, N TI High T-g hole transport polymers for the fabrication of bright and efficient organic light-emitting devices with an air-stable cathode SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE aluminum cathode; efficiency; hole transport layer; ionization potential; luminescence; OLED ID ELECTROGENERATED CHEMILUMINESCENCE; ELECTROLUMINESCENT DIODES; ELECTRON INJECTION; MOLECULAR DESIGN AB An organic electroluminescent device with a luminous efficiency of 20 Im/W, at 14 cd/m(2), and an external quantum efficiency of 4.6% has been fabricated using a high T-g hole transport polymer, a small molecule emission layer, and a LiF/AL cathode. The device quantum efficiency can be increased by tuning the ionization potential of the hole-transport moieties, When tested under pulsed voltage mode, in air at room temperature, and without any encapsulation, the device showed a high peak brightness of 4.4 x 10(6) cd/m(2) at 100 A/cm(2) and an efficiency of 4.4 cd/A. C1 Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. CALTECH, Beckman Inst, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Arnold & Mabel Beckman Labs Chem Synth, Pasadena, CA 91109 USA. RP Jabbour, GE (reprint author), Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. RI grubbs, robert/D-4293-2009; Kippelen, Bernard/I-4058-2013; Shaheen, Sean/M-7893-2013; Barlow, Stephen/E-9754-2010 OI grubbs, robert/0000-0002-0057-7817; Kippelen, Bernard/0000-0002-8417-7051; NR 16 TC 14 Z9 15 U1 3 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JAN PY 2000 VL 36 IS 1 BP 12 EP 17 DI 10.1109/3.817633 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 276FW UT WOS:000084865800003 ER PT J AU Yao, XS Maleki, L AF Yao, XS Maleki, L TI Multiloop optoelectronic oscillator SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article ID MICROWAVE-OSCILLATOR AB We describe and demonstrate a multiloop technique for single-mode selection in an optoelectronic oscillator (OEO). We present experimental results of a dual loop OEO, free running at 10 GHz, that has the lowest phase noise (-140 dBc/Hz at 10 kHz from carrier) of all free-running room-temperature oscillators to date. Finally, we demonstrate the first fiber-optic implementation of the carrier suppression technique to further reduce the close-toe carrier phase noise of the oscillator by at least 20 dB. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yao, XS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 182 Z9 194 U1 4 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD JAN PY 2000 VL 36 IS 1 BP 79 EP 84 DI 10.1109/3.817641 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 276FW UT WOS:000084865800011 ER PT J AU Li, Q Tsang, L Pak, KS Chan, CH AF Li, Q Tsang, L Pak, KS Chan, CH TI Bistatic scattering and emissivities of random rough dielectric lossy surfaces with the physics-based two-grid method in conjunction with the sparse-matrix canonical grid method SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE electromagnetic scattering by rough surfaces; radar scattering ID MONTE-CARLO SIMULATIONS; BACKSCATTERING ENHANCEMENT; ELECTROMAGNETIC-WAVES; 3-DIMENSIONAL SCATTERING; MOMENT-METHOD; ALGORITHM AB Bistatic electromagnetic wave scattering from a two dimensional (2-D) lossy dielectric random rough surfaces [three-dimensional (3-D) scattering problem] with large permittivity is studied. For media with large permittivities, the fields can vary rapidly on the surface. Thus, a dense discretization of the surface is required to implement the method of moment (MoM) for the surface integral equations, Such a dense discretization is also recquired to ensure that the emissivity can be calculated to the recquired accuracy of 0.01 for passive remote sensing applications. We have developed a physics-based two-grid method (PBTG) that can give the accurate results of the surface fields on the dense grid and also the emissivities, The PBTG consists of using two grids on the surface, the coarse grid and the required dense grid. The PBTG only requires moderate increase in central processing unit (CPU) and memory. In this paper, the numerical results are calculated by using the PBTG in conjunction with the sparse-matrix canonical grid (SMCG) method, The computational complexity and memory requirement for the present algorithm are O(N-scg log(N-scg)) and O(N-scg), respectively, where N-scg is the number of grid points on the coarse grid. Numerical simulations are illustrated for root mean square (rms) height of 0.3 wavelengths and correlation length of 1.0 wavelength, The relative permittivity used is as high as (17 + 2i), The numerical results are compared with that of the second-order small perturbation method (SPM), The comparisons show that a large difference in brightness temperature exists between the SPM and numerical simulation results for cases with moderate rms slope. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. City Univ Hong Kong, Dept Elect Engn, Kowloon, Hong Kong, Peoples R China. RP Li, Q (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. OI CHAN, Chi Hou /0000-0002-9718-0831 NR 28 TC 18 Z9 21 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JAN PY 2000 VL 48 IS 1 BP 1 EP 11 DI 10.1109/8.827379 PG 11 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 294RR UT WOS:000085924600001 ER EF