FN Thomson Reuters Web of Science™ VR 1.0 PT S AU Atkins, S Walton, D AF Atkins, S Walton, D GP ACC ACC TI Prediction and control of departure runway balancing at Dallas/Fort Worth airport SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB At many airports, aircraft take off from multiple departure runways. During periods of high departure demand, whether or not the departure runways are balanced directly affects the capacity and efficiency of the airport. This paper begins by investigating the cause of runway imbalances. Homogeneity in the direction of flight during a departure push and the procedures for runway assignments are demonstrated to be the primary source of departure runway imbalances. Second, the paper studies how well departure runways are currently balanced. A method for reconstructing the departure queues that existed at each runway is presented along with results from applying the method. Dallas/Fort Worth (DFW) airport is used as a case study throughout the paper. Controllers currently do not have accurate information about the future departure demand, nor the ability to predict how the surface situation will evolve, necessary to plan efficient traffic management strategies. Finally, the paper introduces automation concepts that will reduce the occurrence and impact of imbalanced departure runways, by providing this information along with traffic management advisories. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 4 TC 0 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 1308 EP 1313 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700226 ER PT S AU Robinson, JE Isaacson, DR AF Robinson, JE Isaacson, DR GP ACC ACC TI Development of a closed-loop testing method for a next-generation terminal-area automation system SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB A next-generation air traffic decision support tool, known as the Active Final Approach Spacing Tool (aFAST), will generate heading, speed and altitude commands to achieve more precise separation of aircraft in the terminal area. The techniques used to analyze the performance of earlier generation decision support tools are not adequate to analyze the performance of aFAST. This paper summarizes the development of a new and innovative fully closed-loop testing method for aFAST. This method, called trajectory feedback testing, closes each aircraft control loop inside of the aFAST scheduling algorithm. Validation of trajectory feedback testing by examination of the variation of aircraft time-of-arrival predictions between schedule updates and the variation of aircraft excess separation distances between simulation runs is presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 11 TC 0 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 1325 EP 1330 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700229 ER PT S AU Alighanbari, M Sayyarrodsari, B Homaifar, A AF Alighanbari, M Sayyarrodsari, B Homaifar, A GP ACC ACC TI Robust adaptive filtering using evolutionary algorithm-based parameter estimation SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE ID PATH AB In this paper we develop effective algorithms for simultaneous robust adaptive filtering/control and unknown parameter estimation. The need for adaptive control of poorly known systems is recognized in a diverse range of applications from active noise cancellation and structural vibration isolation to temperature control in process industry, to equalization in communication systems. Due to the nonlinear dependency of the problem on the unknown parameters, an exact solution to this problem is not known to date. The approach discussed hem uses a robust adaptive filtering/control algorithm to fulfill the control objectives while a structured global search algorithm based on Evolutionary Algorithm identifies the unknown (possibly changing) parameters. Casting the nonlinear parameter estimation problem as an optimization problem, this approach overcomes the unnecessary approximations that am commonly adopted in the existing solutions. At the same time the robustness of the adaptive control algorithm is not compromised since the adaptation criterion used in this algorithm accounts for the uncertainty in parameter estimation as well as the exogenous perturbation signals that are often used to assist parameter estimation. C1 N Carolina Agr & Tech State Univ, NASA, Autonomous Control Engn Ctr, Dept Elect Engn, Greensboro, NC 27411 USA. RP N Carolina Agr & Tech State Univ, NASA, Autonomous Control Engn Ctr, Dept Elect Engn, Greensboro, NC 27411 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 1508 EP 1513 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700260 ER PT S AU Richter, H Misawa, EA AF Richter, H Misawa, EA GP ACC ACC TI Stability analysis of discrete linear systems with quantized input and state measurements SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB This work deals with the equilibrium point and stability analysis of discrete linear systems under quantized feedback. The case of quantized state feedback based on quantized state measurements (QIQM) is treated here. Unlike the case of input quantization (QI) only, there is no closed-form solution for the equilibrium points. However, a computable condition for the origin to be the only equilibrium is given. The stability analysis requires the construction of an equivalent system and a stability theorem for systems with a sector nonlinearity that is multiplicatively perturbed by a bounded function of the state. The analysis reduces to a simple test in the frequency domain; namely, the closed-loop system is globally asymptotically stable about the origin if the Nyquist plot of a system transfer function lies-to the right of a vertical line whose abcissa depends on the 1-norm of the feedback gain. A numerical example of the analysis technique and some guidelines for the synthesis,of a stable feedback gain are also provided. C1 NASA, Stennis Space Ctr, MS 39529 USA. RP NASA, Bldg 8306, Stennis Space Ctr, MS 39529 USA. EM Hanz.Richter@ssc.nasa.gov; misawa@email.ceat.okstate.edu 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 SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 2392 EP 2397 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700417 ER PT S AU Richter, H Misawa, EA AF Richter, H Misawa, EA GP ACC ACC TI Boundary layer eigenvalues in Observer-Based Discrete-Time Sliding Mode Control SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB A new result that helps in the selection of sliding hyperplane coefficients in Observer-Based Discrete-Time Sliding Mode Control is presented. Selection of coefficients is done by analyzing the tracking error dynamics inside the boundary layer, where the closed-loop system has a linear state feedback configuration. The result facilitates assignment of eigenvalues for the system matrix which defines such linear dynamics. C1 NASA, Stennis Space Ctr, MS 39529 USA. RP NASA, Bldg 8306, Stennis Space Ctr, MS 39529 USA. EM Hanz.Richter@ssc.nasa.gov; misawa@email.ceat.okstate.edu NR 8 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 2935 EP 2936 PG 2 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700512 ER PT S AU Richter, H Misawa, EA O'Dell, BD AF Richter, H Misawa, EA O'Dell, BD GP ACC ACC TI Stability analysis of discrete linear systems with quantized input SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE ID FINITE; FEEDBACK AB In this work, the stability-of discrete linear systems under quantized state feedback is addressed. The case with input quantization only (QI) is examined here. This case corresponds to the input quantizer having a much lower resolution that the measurement quantizers, and serves as a logical step in understanding the more complicated case of quantization in the input and in the state measurements (QIQM), treated in a related paper. A simple condition for the origin to be the only equilibrium point is given in terms of the feedback gain, A discrete time formulation of the theory of Absolute Stability is applied-to obtain a stability condition and parameterize feedback gains that result in global asymptotic stability. A numerical example. illustrates the application of the method. C1 NASA, Stennis Space Ctr, MS 39529 USA. RP NASA, Bldg 8306, Stennis Space Ctr, MS 39529 USA. EM Hanz.Richter@ssc.nasa.gov; misawa@email.ceat.okstate.edu; bodell@newton.mae.okstate.edu NR 17 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 2991 EP 2996 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700522 ER PT S AU Ostroff, AJ Bacon, BJ AF Ostroff, AJ Bacon, BJ GP ACC ACC TI Enhanced NDI strategies for reconfigurable flight control SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB A recently proposed method of on-line control design for aircraft reconfiguration is modified to mitigate the effects of effector rate/position saturation and sensor noise in critical measurements while preserving some, perhaps reduced, level of flying qualities. The on-line control design, based on an incremental version of nonlinear dynamic inversion, does not require a complete aerodynamic model of the aircraft, but does require the local control derivatives along with feedback of accelerations and effector positions. Recovery from a variety of failure (stuck or missing effectors) is possible under the original design as long as the working effectors do not enter saturation for extended periods and critical measurements are relatively noise free-an unlikely situation. Here, an improved control allocator minimizes both effector rate and position, utilizing a multi-pass strategy to restore lost control power due to saturation using the remaining unsaturated controls. Command model flying parameters are adaptively manipulated online to comply with reduced levels of control power further reducing saturation. A classically designed compensator placed around each actuator underpins strategy to reduce jitter due to sensor noise in the control variable responses while preserving decoupling of original control. Improvements due to these modifications are demonstrated on an advanced tailless fighter. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 10 TC 2 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 3631 EP 3636 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700634 ER PT S AU Sparks, DW Moerder, DD AF Sparks, DW Moerder, DD GP ACC ACC TI Optimal aircraft control upset recovery with and without component failures SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE C1 NASA, Langley Res Ctr, Guidance & Control Branch, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Guidance & Control Branch, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 3644 EP 3649 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700636 ER PT S AU Belcastro, CM Weinstein, B AF Belcastro, CM Weinstein, B GP ACC ACC TI Distributed detection with data fusion for malfunction detection and isolation in fault tolerant flight control computers SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB It is anticipated that electromagnetic field disturbances will be increasingly problematic for future aircraft control systems, which will perform numerous flight-critical functions. Shielding within the digital systems cannot eliminate these common-cause disturbances, and redundancy is ineffective in accommodating them. This paper presents a distributed detection scheme with data fusion for monitoring the function of redundant processing channels of a flight critical control system during operation. The detection scheme is demonstrated using data collected during closed-loop High Intensity Radiated Fields (HIRF) system effects experiments on a quad-redundant Flight Control Computer (FCC), which is executing Autoland control laws under flight conditions with heavy clear air turbulence. The performance of the monitoring system is assessed. The detection scheme presented in this paper can also be applied to redundancy management in fault tolerant systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Mail Stop 130, Hampton, VA 23681 USA. EM celeste.m.belcastro@larc.nasa.gov; b.weinstein@larc.nasa.gov NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 4224 EP 4231 PG 8 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700736 ER PT S AU Wilson, E Lages, C Mah, R AF Wilson, E Lages, C Mah, R GP ACC ACC TI Gyro-based maximum-likelihood thruster fault detection and identification SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB When building smaller, less expensive spacecraft, there is a need for intelligent fault tolerance vs. increased hardware redundancy. If fault tolerance can be achieved using existing navigation sensors, cost and vehicle complexity can be reduced. A maximum likelihood-based approach to thruster fault detection and identification (FDI) for spacecraft is developed here and applied in simulation to the X-38 space vehicle. The system uses only gyro signals to detect and identify hard, abrupt, single- and multiple-jet on- and off-failures. Faults are detected within one second and identified within one to five seconds. C1 NASA, Ames Res Ctr, Smart Syst Res Lab, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Smart Syst Res Lab, MS 269-1, Moffett Field, CA 94035 USA. EM chris.lages@intellization.com; rmah@mail.arc.nasa.gov NR 10 TC 3 Z9 4 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 4525 EP 4530 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700787 ER PT S AU Belcastro, CM Chang, BC AF Belcastro, CM Chang, BC GP ACC ACC TI Uncertainty modeling for robustness analysis of failure detection & accommodation systems SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB Formal robustness analysis of failure detection and accommodation systems could play an important role in their validation and ultimate certification. However, formulation of linear fractional transformation (LFT) models can be very difficult for complex parameter-dependent systems. This paper presents a matrix-based computational approach that can be implemented in software for obtaining LFT models of complex systems involving parametric uncertainties, faults, and failures. Several examples are presented, including, a modeling framework for performing robustness analyses of faulty uncertain systems and failure detection and accommodation systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, Mail Stop 161, Hampton, VA 23681 USA. EM christine.m.belcastro@larc.nasa.gov; bchang@coe.drexel.edu NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 4776 EP 4782 PG 7 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700833 ER PT S AU Eure, K AF Eure, K GP ACC ACC TI Implementations of real-time system identification using recursive techniques SO PROCEEDINGS OF THE 2002 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT 20th Annual American Control Conference (ACC) CY MAY 08-10, 2002 CL ANCHORAGE, AK SP Amer Automat Control Council, IFAC, SICE AB Recursive identification techniques offer the ability to compute the transfer function of a system in real-time. This mathematical representation of a system may be used for various tasks such as health monitoring and feedback control. This paper presents the mathematical development of the Fast Transversal filter. It follows reference [1], but adds to it by the introduction of a forgetting factor to accommodate changes in the plant. The FTF's ability to track plant changes in real time offers applications in adaptive feedback control and adaptive fault detection. An example of the use of the FTF in feedback control is presented for a simple plant. Also, it is demonstrated that the FTF may be used to estimate a mathematical model of a Flight Control Computer for command signals during the Autoland phase. The example shown in this paper is for a B737 Autolander. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-7298-0 J9 P AMER CONTR CONF PY 2002 VL 1-6 BP 4807 EP 4812 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Automation & Control Systems; Computer Science; Engineering GA BV44D UT WOS:000178974700838 ER PT B AU Vengerov, D Berenji, HR Vengerov, A AF Vengerov, D Berenji, HR Vengerov, A GP IEEE IEEE TI Adaptive coordination among fuzzy reinforcement learning agents performing distributed dynamic load balancing SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOL 1 & 2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems CY MAY 12-17, 2002 CL HONOLULU, HI SP IEEE, IEEE Neural Network Soc AB In this paper we present an adaptive multi-agent coordination algorithm applied to the problem of distributed dynamic load balancing. As a specific example, we consider the problem of dynamic web caching in the Internet. In our general formulation of this problem, each agent represents a mirrored piece of content that tries to move itself closer to areas of the network with a high demand for this item. Each agent in our model uses a fuzzy rulebase for choosing the optimal direction of motion and adjusts the parameters of this rulebase using reinforcement learning. The resulting architecture for multi-agent coordination among fuzzy reinforcement learning agents (MAC-FRL) allows the team of agents to adaptively redistribute its members in the environment to match the changing pattern of demand. We simulate the performance of MAC-FRL and show that it significantly improves performance over non-coordinating agents. C1 NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, Moffett Field, CA 94035 USA. RP Vengerov, D (reprint author), NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, MS 269-2, Moffett Field, CA 94035 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7280-8 PY 2002 BP 179 EP 184 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BU95M UT WOS:000177476600032 ER PT B AU Howard, A Seraji, H Werger, B AF Howard, A Seraji, H Werger, B GP IEEE IEEE TI Fuzzy terrain-based path planning for planetary rovers SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOL 1 & 2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems CY MAY 12-17, 2002 CL HONOLULU, HI SP IEEE, IEEE Neural Network Soc AB This paper presents a fuzzy terrain-based path planning method for planetary rovers operating on rough natural terrain. The focus of this approach is on planning an optimally safe path of minimum traversal cost, which is calculated from linguistic descriptors of terrain traversability. The method incorporates the Traversability Map, a fuzzy map representation of traversal difficulty of the terrain, into the path planning logic. The search methodology uses a traversal cost function that is derived directly from this Traversability Map. The path planning method is developed in detail and experimental results are presented. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7280-8 PY 2002 BP 316 EP 320 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BU95M UT WOS:000177476600056 ER PT B AU Vengerov, D Berenji, HR AF Vengerov, D Berenji, HR GP IEEE IEEE TI Using fuzzy reinforcement learning for power control in wireless transmitters SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOL 1 & 2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems CY MAY 12-17, 2002 CL HONOLULU, HI SP IEEE, IEEE Neural Network Soc AB Fuzzy set theory was recently shown to be an effective tool for generalizing the learned experience between similar states in reinforcement learning problems with large or continuous state spaces. In our previous work we presented the first convergence proof for an algorithm combining fuzzy sets and reinforcement learning. In this paper we apply our algorithm to a very challenging wireless power control problem characterized by heavily delayed rewards combined with several sources of randomness. The results show a considerable improvement in performance as compared to the optimal constant power transmission. C1 NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, Mt View, CA 94035 USA. RP Vengerov, D (reprint author), NASA, Ames Res Ctr, Intelligent Inference Syst Corp, Computat Sci Div, MS 269-2, Mt View, CA 94035 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 0-7803-7280-8 PY 2002 BP 797 EP 802 PG 6 WC Computer Science, Artificial Intelligence SC Computer Science GA BU95M UT WOS:000177476600142 ER PT B AU Howard, A AF Howard, A GP IEEE IEEE TI A novel information fusion methodology for intelligent terrain analysis SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOL 1 & 2 LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems CY MAY 12-17, 2002 CL HONOLULU, HI SP IEEE, IEEE Neural Network Soc AB This paper presents a novel information fusion methodology for intelligent terrain analysis. In our application, we define information as terrain characteristics derived from sensor data extracted from on-board spacecraft sensors. The fuzzy-logic construct allows us to represent the terrain characteristics using an easily understandable, linguistic approach. Once derived, these fuzzy terrain characteristics are blended together using a fuzzy rule base to produce a coherent representation of terrain safety. The fused information is then used to autonomously select a safe landing site for spacecraft touchdown. The fuzzy terrain analysis and fusion methodology is explained in detail in this paper. Computer simulation results are provided to show the viability of the approach. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Howard, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7280-8 PY 2002 BP 1472 EP 1475 PG 4 WC Computer Science, Artificial Intelligence SC Computer Science GA BU95M UT WOS:000177476600258 ER PT S AU Prestage, JD Chung, S Burt, E Maleki, L Tjoelker, RL AF Prestage, JD Chung, S Burt, E Maleki, L Tjoelker, RL GP IEEE IEEE TI Stability measurements between Hg+ lite 12-pole clocks SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM & PDA EXHIBITION SE IEEE International Frequency Control Symposium LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium and PDA Exhibition CY MAY 29-31, 2002 CL NEW ORLEANS, LA SP IEEE Ultrason, Ferroelect & Frequency Control Soc, Piezoelect Devices Assoc DE atomic clocks; ion traps; mercury ions ID ION-TRAP AB We describe frequency stability measurements of two Hg-ion clocks based upon linear 12-pole shuttle ion traps. The inter-comparison was carried out over several multi-day intervals with the short-term stability of each clock better than 2x10(-13) at 1 second. Longer-term stability as good as 3x10(-16) was demonstrated for these clocks. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-7082-1 J9 P IEEE INT FREQ CONT PY 2002 BP 459 EP 462 DI 10.1109/FREQ.2002.1075926 PG 4 WC Automation & Control Systems; Engineering, Manufacturing; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Automation & Control Systems; Engineering; Optics; Physics GA BV43J UT WOS:000178928900075 ER PT S AU Burt, EA Prestage, JD Tjoelker, RL AF Burt, EA Prestage, JD Tjoelker, RL GP IEEE IEEE TI Probing magnetic field effects in 12-pole linear ion trap frequency standards SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM & PDA EXHIBITION SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium and PDA Exhibition CY MAY 29-31, 2002 CL NEW ORLEANS, LA SP IEEE Ultrason, Ferroelect & Frequency Control Soc, Piezoelect Devices Assoc DE linear ion trap frequency standard; 12-pole ion trap; Zeeman shift AB The second-order Zeeman shift in a 12-pole buffer-gas-cooled linear ion trap frequency standard is characterized. Results for magnetic shielding effectiveness and long term stability against magnetic field perturbations are presented. The clock frequency is found to be stable against typical ambient magnetic field fluctuations to less than 2x10(-16). The frequency shift as a function of ion number is also studied and a plausibility argument is given relating this to magnetic field inhomogeneity. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Burt, EA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 5 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-7082-1 J9 P IEEE INT FREQ CONT PY 2002 BP 463 EP 468 DI 10.1109/FREQ.2002.1075927 PG 6 WC Automation & Control Systems; Engineering, Manufacturing; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Automation & Control Systems; Engineering; Optics; Physics GA BV43J UT WOS:000178928900076 ER PT S AU Klipstein, WM Enzer, DG AF Klipstein, WM Enzer, DG GP IEEE IEEE TI Mitigation of the light shift in laser cooled clocks without mechanical shutters SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM & PDA EXHIBITION SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium and PDA Exhibition CY MAY 29-31, 2002 CL NEW ORLEANS, LA SP IEEE Ultrason, Ferroelect & Frequency Control Soc, Piezoelect Devices Assoc DE light shift; frequency standard; cesium AB We propose an approach for keeping the light shift in laser cooled frequency standards down to the 10(-17) level without the use of mechanical shutters. For laser systems using a master-slave laser configuration, cutting the injection power to a slave causes it to lase at its free-running wavelength, often two or more nanometers off from the atomic resonance. This approach does not apply to laser systems using power amplifiers. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Klipstein, WM (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-7082-1 J9 P IEEE INT FREQ CONT PY 2002 BP 484 EP 487 DI 10.1109/FREQ.2002.1075932 PG 4 WC Automation & Control Systems; Engineering, Manufacturing; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Automation & Control Systems; Engineering; Optics; Physics GA BV43J UT WOS:000178928900081 ER PT S AU Wang, RT Dick, GJ AF Wang, RT Dick, GJ GP IEEE IEEE TI Cryo-cooled Sapphire Oscillator with mechanical compensation SO PROCEEDINGS OF THE 2002 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM & PDA EXHIBITION SE IEEE International Frequency Control Symposium LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium and PDA Exhibition CY MAY 29-31, 2002 CL NEW ORLEANS, LA SP IEEE Ultrason, Ferroelect & Frequency Control Soc, Piezoelect Devices Assoc AB We present test results for a short-term frequency standard, 40K Compensated Sapphire Oscillator (CSO). Included are measured resonator Q values, cryocooler vibration data, silver spacer construction process, and copper wall sensitivity. The 40K CSO design goals are a frequency stability of 1X10(-14) (1 second less than or equal to tau less than or equal to 100 seconds), a year or more continuous operation, and a compact rack-mount configuration. The 40K CSO[1] bridges the gap of two previous technology 10K CSO[2] and 77K CSO[3]. In particular, the 10K CSO incorporated a Gifford-McMahon type of cryocooler with no cryogens, while the 77K CSO developed thermo-mechanical compensation operating at 80 K. The 40K CSO can serve as an independent oscillator or as a "slaved" local oscillator controlled by atomic standards like Hg ion trap, enabling their inherent performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-7082-1 J9 P IEEE INT FREQ CONT PY 2002 BP 543 EP 547 DI 10.1109/FREQ.2002.1075942 PG 5 WC Automation & Control Systems; Engineering, Manufacturing; Engineering, Electrical & Electronic; Optics; Physics, Applied SC Automation & Control Systems; Engineering; Optics; Physics GA BV43J UT WOS:000178928900091 ER PT S AU Stosic, DK Lux, JP AF Stosic, DK Lux, JP GP IEEE IEEE TI Radar breadboard for DSP scatterometer SO PROCEEDINGS OF THE 2002 IEEE RADAR CONFERENCE SE Radar Conference LA English DT Proceedings Paper CT 2002 IEEE Radar Conference CY APR 22-25, 2002 CL LONG BEACH, CA SP IEEE Los Angeles Council, IEEE Aerosp & Electr Syst Soc, Northrop Grumman Corp, Raytheon Co AB The design and test results for the Radio Frequency (RF) portion of a breadboard polarimetric scatterometer operating at 13.402 GHz are presented. To evaluate the feasibility of a programmable Digital Signal Processing (DSP) approach for a follow-on scatterometer similar to SeaWinds (scheduled for launch in winter 2002) an integrated breadboard has been developed at the Jet Propulsion Laboratory (JPL). Early breadboards of this type have been identified as valuable assets in developing effective subsystem requirements for the eventual flight instrument. Many compatibility and partitioning issues between the RF and DSP hardware are addressed with empirical results derived from the aforementioned breadboard. The RF portion of the breadboard consists of a dual channel receiver, heterodyning the received signal of 13.402 GHz down to an IF of 37 MHz and a single channel transmitter, that converts the I/Q baseband transmit waveform up to Ku band. The breadboard makes provision for emulating capabilities such as programmable attenuators, loop-back calibration, and saturation effects in an actual instrument's power amplifier. It also provides control interfaces to allow early verification of software control algorithms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stosic, DK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 161-213, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1097-5764 BN 0-7803-7357-X J9 RADAR CONF PY 2002 BP 168 EP 175 DI 10.1109/NRC.2002.999715 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology; Telecommunications SC Engineering; Remote Sensing; Imaging Science & Photographic Technology; Telecommunications GA BU50P UT WOS:000176199500030 ER PT S AU Brugarolas, PB Safonov, MG AF Brugarolas, PB Safonov, MG GP IEEE IEEE TI A data driven approach to learning dynamical systems SO PROCEEDINGS OF THE 41ST IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 SE IEEE CONFERENCE ON DECISION AND CONTROL - PROCEEDINGS LA English DT Proceedings Paper CT 41st IEEE Conference on Decision and Control CY DEC 10-13, 2002 CL LAS VEGAS, NV SP IEEE Control Syst Soc, Soc Ind & Appl Math, Inst Operat Res & Management Sci DE control; system identification; behavioral systems; adaptive control; model validation; set membership; falsification; experimental data ID IDENTIFICATION AB This paper presents a mathematical framework for learning (properties of a dynamical system) from experimental data via hypothesis falsification, and its application to control and system identification problems. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Brugarolas, PB (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0191-2216 BN 0-7803-7516-5 J9 IEEE DECIS CONTR P PY 2002 BP 4670 EP 4675 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Operations Research & Management Science SC Automation & Control Systems; Computer Science; Operations Research & Management Science GA BW26E UT WOS:000181352300839 ER PT B AU Thigpen, W Hacker, TJ McGinnis, LF Athey, BD AF Thigpen, W Hacker, TJ McGinnis, LF Athey, BD BE Caulfield, HJ Chen, SH Duro, R Honavar, V Kerre, EE Lu, M Romay, MG Shih, TK Ventura, D Wang, PP Yang, YY TI Distributed accounting on the grid SO PROCEEDINGS OF THE 6TH JOINT CONFERENCE ON INFORMATION SCIENCES LA English DT Proceedings Paper CT 6th Joint Conference on Information Sciences CY MAR 08-13, 2002 CL RES TRIANGLE PK, NC SP Assoc Intelligent Machinery, Informat Sci Journal, Duke Univ, Acad Affairs, Tamkang Univ, N Carolina Biotechnol Ctr, GalxoSmithKline, George Mason Univ AB The Internet has been engineered over the last thirty years to interconnect devices across the globe in an adaptable and fault-tolerant manner. Along with the development of the Internet, a suite of distributed applications ranging from electronic mail to the World Wide Web that rely upon the global Internet have grown in use and scope in parallel with the universal deployment and use of the Internet. By the late 1990's, the Internet was adequately equipped to move vast amounts of data between HPC systems, and efforts were initiated to link together the national infrastructure of high performance computational and data storage resources together into a general computational utility "grid", analogous to the national electrical power grid infrastructure. The purpose of the computational grid is to provide dependable, consistent, pervasive, and inexpensive access to computational resources for the computing community in the form of a computing utility [1]. This paper presents a fully distributed view of Grid usage accounting and a methodology for allocating Grid computational resources for use on a Grid computing system. The Grid will contain a large number of unconnected sites, and these sites will need to exchange accounting and bid/quote information. Specifically, three issues are being addressed by the Global Grid Forum Accounting Working Group: mapping resource usage to Grid users; defining a usage economy or methods for resource exchange; and describing implementation standards that minimize and compartmentalize the tasks required for a site to participate in Grid accounting. For an accounting system to be functional in a Grid environment, it needs to be decentralized, scalable and flexible. It must have a minimum impact on local accounting and should not make any limiting assumptions about whether accounting is done by user, group, project, or site. The requirements on the remote site will be to track the resources used by the requesting job and then pass this information back to the requesting site in some standardized format. At the requesting site, the information can then be accrued as needed for local requirements. A distributed allocation and accounting approach, using a consumer/supplier or client/server structure will work across multiple sites and satisfy the needs of the participating administrative and policy domains. C1 NASA, NAS Syst Div, Ames, IA USA. RP Thigpen, W (reprint author), NASA, NAS Syst Div, Ames, IA USA. NR 1 TC 2 Z9 2 U1 0 U2 0 PU ASSOC INTELLIGENT MACHINERY PI DURHAM PA PO BOX 90291, DURHAM, NC 27708-0291 USA BN 0-9707890-1-7 PY 2002 BP 1147 EP 1150 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BV54W UT WOS:000179331800268 ER PT J AU Struk, PM Dietrich, DL Ikegami, M Xu, GW AF Struk, PM Dietrich, DL Ikegami, M Xu, GW TI Interacting droplet combustion under conditions of extinction SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID BURNING DROPLETS; RATES AB This paper presents the results of an experimental investigation into the extinction behavior of single droplets and binary droplet arrays of decane fuel in normal gravity and microgravity. The test ambients were air at reduced pressure for the normal gravity experiments and nitrogen/oxygen and helium/oxygen at reduced pressure for the microgravity experiments. The data show that interaction effects have a stronger influence on the extinction behavior of a binary array than the quasi-steady burning behavior. In normal gravity, the burning rate constant is only a very weak function of the interdroplet spacing at initial none dimensional separation distances greater than 5. The extinction droplet diameter, however, is much smaller (if it exists) for the droplet array at an instantaneous non-dimensional spacing of approximately 20. The microgravity experiments in nitrogen/oxygen (0.15 oxygen mole fraction) ambients exhibited different extinction behavior than the normal gravity tests. In this ambient condition, the flame surrounding the binary array always extinguished at a larger droplet diameter compared with single droplets. The microgravity experiments in the helium/oxygen (0.25 oxygen mole fraction) ambients exhibited behavior opposite of the nitrogen diluted tests with the binary array extinguishing at smaller droplet diameters than a single droplet. For the microgravity experiments, the observed difference between the two ambients is attributed to the importance of radiative loss. The nitrogen/oxygen tests had larger, weaker flames and smaller burning rates and consequently were affected more significantly by radiative loss from the flame zone compared to the helium/oxygen tests. A qualitative explanation of the different extinction behavior is detailed in the paper. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Natl Inst Adv Ind Sci & Technol, Sapporo, Hokkaido, Japan. RP Struk, PM (reprint author), NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RI Struk, Peter/M-1651-2013 OI Struk, Peter/0000-0001-8221-8369 NR 25 TC 4 Z9 5 U1 0 U2 5 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 609 EP 615 DI 10.1016/S1540-7489(02)80078-5 PN 1 PG 7 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KK UT WOS:000182866100074 ER PT J AU Vander Wal, RL Hall, LJ Berger, GM AF Vander Wal, RL Hall, LJ Berger, GM TI The chemistry of premixed flame synthesis of carbon nanotubes using supported catalysts SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID CHEMICAL-VAPOR-DEPOSITION; FILAMENTOUS CARBON; GROWTH; GAS; CO; DECOMPOSITION; PARTICLES; COBALT; FIBERS; IRON AB A premised flame is used to create the reactive environment for carbon nanotube (CNT) synthesis using stainless steel mesh supporting Co as catalyst. The CNT relative growth density, morphology, and internal structure are interpreted in terms of the chemical composition of the flame gases. Different flame gas compositions are produced by varying the fuel/air equivalence ratio, phi. For phi > 1.62, carbon deposition occurs too rapidly relative to reactive etching of surface carbon by species such as H-2, CO2, and H2O. For phi < 1.62, the reverse trend of insufficient carbon supply relative to the rate of carbon removal again stunts CNT growth. A value of phi = 1.62 produces CNTs with the best yield, uniformity, and graphitic structure as gauged by scanning and transmission electron microscopies. Yields of up to 1% mass increase of catalyzed CNTs grown upon this catalyst-support system are measured. Initial scalability is demonstrated where CNTs can be uniformly synthesized upon catalyst-coated meshes greater than 2 cm(2) in area. C1 NASA, Glenn Res Ctr, NCMR, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA, Glenn Res Ctr, NCMR, M-S 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 31 TC 16 Z9 16 U1 0 U2 3 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 1079 EP 1085 DI 10.1016/S1540-7489(02)80136-5 PN 1 PG 7 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KK UT WOS:000182866100132 ER PT J AU Ibarreta, AF Driscoll, JF Feikema, DA AF Ibarreta, AF Driscoll, JF Feikema, DA TI Markstein numbers of negatively stretched premixed flames: Microgravity measurements and computations SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID LAMINAR BURNING VELOCITIES; AIR FLAMES; COMBUSTION; MIXTURES; SCHEMES AB The effect of flame stretch, composed of strain and curvature, plays a major role in the propagation of turbulent premixed flames. Although all forms of stretch, both positive and negative, are present in turbulent conditions, little research has been focused on the stretch due to curvature. The present study quantifies the Markstein number (which characterizes the sensitivity of the flame propagation speed to the imposed stretch rate) for an inwardly propagating flame (IPF). This flame is of interest because it is negatively stretched and is subjected to curvature effects alone, without the competing effects of strain. In an extension of our previous work, microgravity experiments were run using a vortex-flame interaction to create a pocket of reactants surrounded by an IPF. Computations using the RUN-IDL code of Rogg were also performed in order to explain the measurements. It was found that the Markstein number of an IPF, for both the microgravity experiment and the computations, is significantly larger than that of an outwardly propagating flame. Further insight was gained by running the computations for the simplified (hypothetical) cases of one-step chemistry, equal diffusivities, and negligible heat release. Results provide additional evidence that the Markstein numbers associated with strain and curvature have different values. C1 Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. NASA, Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RP Ibarreta, AF (reprint author), Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. NR 28 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1540-7489 EI 1873-2704 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 1435 EP 1443 DI 10.1016/S1540-7489(02)80176-6 PN 2 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500003 ER PT J AU Rhatigan, JL Sung, CJ Tien, JS AF Rhatigan, JL Sung, CJ Tien, JS TI On solid trioxane combustion in stagnation point flows SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID DIFFUSION FLAMES; EXTINCTION; IGNITION; 1,3,5-TRIOXANE; DECOMPOSITION; PARAMETERS; SURFACES; AIR AB Response, flame structure, and extinction limits of solid trioxane (C3H6O3) combustion in stagnation-point flows are computationally studied with detailed chemistry, transport properties, and radiation representation. While a solid surface radiation model addresses emission and absorption by the surface, a narrowband radiation model, with carbon dioxide, carbon monoxide, and water vapor as the gas-phase participating media, is employed to describe the gas-phase radiation. Comparison of adiabatic solutions to solutions that include surface radiation only and gas-phase and surface radiation is presented over the flammable regime, with emphasis on the low-stretch regime of the radiatively participating flames. When only surface radiation is included, two extinction limits exist, namely the blow-off limit and the low-stretch radiative limit, and the burning rates and maximum flame temperatures are lower than those of the adiabatic counterpart, as expected. With the inclusion of surface and gas-phase radiation, results show that, while flame temperatures are even lower, the burning rate of the trioxane diffusion flame may actually exceed the adiabatic limit and increase at low stretch rate due to radiative feedback from the flame to the surface. Reaction pathways leading to trioxane oxidation are also analyzed. High-temperature and low-temperature reaction pathways identified previously in homogeneous kinetics studies are sustained in heterogeneous trioxane combustion. Furthermore, potential effects of radical recombination at the solid surface are assessed and discussed. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Rhatigan, JL (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 31 TC 3 Z9 3 U1 1 U2 4 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 1645 EP 1652 DI 10.1016/S1540-7489(02)80202-4 PN 2 PG 8 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500029 ER PT J AU Dahm, WJA Chen, SJ Silver, JA Mullin, JA Piltch, ND AF Dahm, WJA Chen, SJ Silver, JA Mullin, JA Piltch, ND TI Mixture fraction measurements via WMS-ITAC in a microgravity vortex ring diffusion flame SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV AB Flame-vortex interaction experiments conducted under microgravity conditions provide a carefully controllable environment in which fundamental combustion science issues relevant to turbulent flame processes can be investigated. The present study provides results from microgravity measurements of mixture fraction fields and differential-diffusion effects associated with mixing and combustion in a vortex ring diffusion flame. The experiments are based on a new extension of wavelength modulation spectroscopy (WMS) that uses iterated temperatures with assumed chemistry (ITAC) based on chemical equilibrium state relations. The high degree of axisymmetry achieved in these vortex ring experiments permits Abel inversion to yield the space- and time-varying mixture fraction field xi(x,t) throughout the fuel-rich portions of the flame, from which major species and temperature are obtained. The WMS-ITAC method uses the measured local temperature-dependent absorbance of a single major species, in this case methane, to find the local mixture fraction xi that corresponds to mutually consistent values of the local temperature T(xi) and the concentration Y(xi) of the absorbing species. Comparisons of the resulting fields obtained with two different sets of state relations, one of which accounts for the differing diffusivities of individual molecular species and temperature, permit assessment of differential-diffusion effects in the vortex ring diffusion flame. The results show how differential diffusion alters the spatiotemporal structure of such flame-vortex interactions. C1 Univ Michigan, Dept Aerosp Engn, Lab Turbulence & Combust, Ann Arbor, MI 48109 USA. SW Sci Inc, Santa Fe, NM 87505 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dahm, WJA (reprint author), Univ Michigan, Dept Aerosp Engn, Lab Turbulence & Combust, Ann Arbor, MI 48109 USA. NR 17 TC 3 Z9 3 U1 0 U2 1 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2519 EP 2526 DI 10.1016/S1540-7489(02)80307-8 PN 2 PG 8 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500134 ER PT J AU Prasad, K Nakamura, Y Olson, SL Fujita, O Nishizawa, K Ito, K Kashiwagi, T AF Prasad, K Nakamura, Y Olson, SL Fujita, O Nishizawa, K Ito, K Kashiwagi, T TI Effect of wind velocity on flame spread in microgravity SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID ENVIRONMENT; TRANSITION AB A three-dimensional, time-dependent model is developed describing ignition and subsequent transition to flame spread over a thermally thin cellulosic sheet heated by external radiation in a microgravity environment. A low Mach number approximation to the Navier-Stokes equations with global reaction rate equations describing combustion in the gas phase and the condensed phase is numerically solved. The effects of a slow external wind (1-20 cm/s) on flame transition are studied in an atmosphere of 35% oxygen concentration. The ignition is initiated at the center part of the sample by generating a line-shape flame along the width of the sample. The calculated results are compared with data obtained in the 10 s drop tower. Numerical results exhibit flame quenching at a wind speed of 1.0 cm/s, two localized flames propagating upstream along the sample edges at 1.5 cm/s, a single line-shape flame front at 5.0 cm/s, and three flames structure observed at 10.0 cm/s (consisting of a single line-shape flame propagating upstream and two localized flames propagating downstream along sample edges), followed by two line-shape flames (one propagating upstream and another propagating downstream) at 20.0 cm/s. These observations qualitatively compare with experimental data. Three-dimensional visualization of the observed flame complex, fuel concentration contours, oxygen and reaction rate isosurfaces, and convective and diffusive mass flux are used to obtain a detailed understanding of the controlling mechanism. Physical arguments based on the lateral diffusive flux of oxygen, fuel depletion, the oxygen shadow of the flame, and the heat release rate are constructed to explain the various observed flame shapes. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Nagoya Univ, Dept Mech Engn, Nagoya, Aichi, Japan. NASA, Glenn Res Ctr, Micrograv Combust Sci Branch, Cleveland, OH 44135 USA. Hokkaido Univ, Dept Mech Engn, Sapporo, Hokkaido 060, Japan. RP Prasad, K (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RI Fujita, Osamu/D-6797-2012 NR 10 TC 5 Z9 7 U1 0 U2 5 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2553 EP 2560 DI 10.1016/S1540-7489(02)80311-X PN 2 PG 8 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500138 ER PT J AU Miller, FJ Easton, JW Marchese, AJ Ross, HD AF Miller, FJ Easton, JW Marchese, AJ Ross, HD TI Gravitational effects on flame spread through non-homogeneous gas layers SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV AB Flame propagation through non-uniformly premixed gases occurs in several common combustion situations. Compared with the more usual limiting cases of diffusion or uniformly premixed flames, the practical concern of non-uniform premixed gas flame spread has received scant attention, especially regarding the potential role of gravity. This research examines a system in which a fuel concentration gradient exists normal to the direction of flame propagation and parallel with the gravitational vector. This paper presents experimental and numerical results for flame spread through alcohol/air layers formed by diffusive evaporation of liquid fuel at temperatures between the flash-point temperature and the stoichiometric temperature. A gallery, which had either the top and/or one end open to maintain constant pressure, surrounded the test section. The numerical simulations and experiments conducted include normal and microgravity cases. An interferometer was used, in normal gravity only, to determine the initial fuel layer thickness and fuel concentration distribution before and during flame spread. Both the model and experimental results show that the absence of gravity results in a faster spreading flame, by as much as 80% depending on conditions. This is the opposite effect to that predicted by an independent model reported earlier in this symposium series. Determination of the flame height showed that the flame was taller in microgravity, an effect also seen in the results of the numerical model reported here. Having a gallery lid results in faster flame spread, an effect more pronounced at normal gravity, demonstrating the importance of enclosure geometry. The interferometry and numerical model both indicated a redistribution of fuel vapor ahead of the flame. Numerical simulations show that, despite the rapid flame spread in these systems, the presence of gravity strongly affects the overall flow field in the gallery. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. Rowan Univ, Glassboro, NJ 08028 USA. RP Miller, FJ (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. NR 12 TC 9 Z9 9 U1 0 U2 3 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2561 EP 2567 DI 10.1016/S1540-7489(02)80312-1 PN 2 PG 7 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500139 ER PT J AU Feier, II Shih, HY Sacksteder, KR Tien, JS AF Feier, II Shih, HY Sacksteder, KR Tien, JS TI Upward flame spread over thin solids in partial gravity SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID SPEED CONCURRENT FLOW; FUEL; MECHANISMS AB Experiments to observe upward and downward flame spread and extinction over a thin solid fuel in partial-gravity environments were conducted in an aircraft flying parabolic trajectories. In the upward spreading case, flames with constant lengths and steady spread rates were observed using narrow fuel samples in reduced pressures. The upward flame spread rates and the flame and pyrolysis lengths increased linearly with the gravity level. The proportionality constants, however, increased with pressure and sample width. For comparison, downward spreading tests were also conducted using the same reduced-pressure atmospheres needed to obtain steady flames in the upward spreading case. In downward spreading, the steady spread rates and the flammability boundary exhibited a non-monotonic dependence on gravity. This behavior is attributed to competition between finite-gas-phase residence times in the flame stabilization zone and radiative heat losses from the flame. Throughout the accessible range of partial gravity, the upward spreading flames propagated at higher speeds than the downward spreading flames and the fuel is more flammable in the upward spread direction. A three-dimensional concurrent-flow flame-spreading model, originally developed for forced flows in a duct at microgravity, was reformulated and numerically solved for buoyant flow. The numerical flame spread simulation provides detailed flame structure including gas flow and temperature fields, oxygen and fuel transport, and solid temperature and thickness distributions and predicts the essential three-dimensional features observed for the narrow, reduced pressure flames. C1 Case Western Reserve Univ, Cleveland, OH 44135 USA. Ind Technol Res Inst, Ctr Aviat & Space Technol, Hsinchu 31040, Taiwan. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Feier, II (reprint author), Case Western Reserve Univ, Cleveland, OH 44135 USA. OI Shih, Hsin-Yi/0000-0003-1053-2169 NR 21 TC 10 Z9 11 U1 0 U2 7 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2569 EP 2577 DI 10.1016/S1540-7489(02)80313-3 PN 2 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500140 ER PT J AU Chen, SJ Silver, JA Dahm, WJA Piltch, ND AF Chen, SJ Silver, JA Dahm, WJA Piltch, ND TI Mixture fraction measurements via WMS/ITAC in a laminar diffusion flame SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV ID PROFILES AB A new approach to determine the mixture fraction at all positions in a flame, using experimental measurements of as few as a single species, is described. This approach combines measurements using diode laser wavelength modulation spectroscopy (WMS) and a method termed iterative temperature with assumed chemistry (ITAC). Combustion models used in ITAC include equilibrium and near-equilibrium chemistry and are based on the understanding of the important flow, fluid transport, and chemical properties of the system. The conserved scalar approach is used to model the flow-chemistry coupling and provides the state relationships to relate the reactants and products to mixture fraction in the case of equilibrium and near-equilibrium chemistry. In this work, the basic WMS/ITAC method is described and validated for a laminar diffusion flame in a Wolfhard-Parker burner. Methane concentration and temperature are measured and compared to published and ITAC results. There is good agreement between the direct measurements and ITAC results. These results agree well with published results, considering the differences in ambient pressure. Effects, including differential diffusion, radiative heat loss, and finite-rate chemistry, on the combustion models are addressed and found to be important for the simple laminar diffusion flame. Extension of WMS/ITAC to more complex combustion systems which include turbulence and non-equilibrium chemistry are suggested. C1 SW Sci Inc, Santa Fe, NM 87505 USA. Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chen, SJ (reprint author), SW Sci Inc, 1570 Pacheco St,Suite E-11, Santa Fe, NM 87505 USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2679 EP 2685 DI 10.1016/S1540-7489(02)80326-1 PN 2 PG 7 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500153 ER PT J AU King, MK AF King, MK TI A simplified two-reaction zone model of magnesium combustion in carbon dioxide SO PROCEEDINGS OF THE COMBUSTION INSTITUTE LA English DT Article; Proceedings Paper CT 29th International Combustion Symposium CY JUL 21-26, 2002 CL HOKKAIDO UNIV, SAPPORO, JAPAN HO HOKKAIDO UNIV AB A simplified model of magnesium particle combustion in pure carbon dioxide has been developed and utilized for prediction of particle burning times. This model includes two reaction zones-an outer zone (shell) where magnesium reacts at a transport-limited rate with carbon dioxide to form condensed magnesium oxide plus CO and an inner zone, at the particle surface, where CO reacts with liquid magnesium to form solid carbon and solid magnesium oxide, which remain with the particle. The main simplifications utilized are the neglect of reactions in the gaseous regions inside and outside the outer shell and use of average transport properties across these regions. First, two limiting cases, the first with transport-limited reaction rate at the surface and the second with zero reaction rate at the surface, were examined. Next, finite-rate kinetics of the surface reaction, with the reaction rate constant being the product of the collision rate of CO molecules with the surface and a reaction probability expressed in Arrhenius form, was examined, with the activation energy of the Mg + CO reaction being varied parametrically. Model development and resultant burning rate and burning time predictions are presented. For the two limiting cases, predicted burning times were proportional to the square of the initial particle radius, while for the finite kinetics cases, the dependency was predicted to be slightly less than second order. Comparison of predictions with the limited experimental data available indicates reasonable agreement between theory and data. C1 NASA Headquarters, Washington, DC 20546 USA. RP King, MK (reprint author), NASA Headquarters, Code UG,300 E St SW, Washington, DC 20546 USA. NR 9 TC 8 Z9 11 U1 2 U2 9 PU COMBUSTION INST PI PITTSBURGH PA 5001 BAUM BOULEVARD, STE 635, PITTSBURGH, PA 15213-1851 USA SN 0082-0784 J9 P COMBUST INST JI Proc. Combust. Inst. PY 2002 VL 29 BP 2931 EP 2938 DI 10.1016/S1540-7489(02)80358-3 PN 2 PG 8 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 678KN UT WOS:000182866500185 ER PT S AU Sampson, MJ AF Sampson, MJ GP ESA ESA TI The NASA EEE Parts Assurance Group (NEPAG) an evolving approach to maximizing space parts assurance resources SO PROCEEDINGS OF THE EUROPEAN SPACE COMPONENTS CONFERENCE - ESCCON 2002 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT European Space Components Conference CY SEP 24-27, 2002 CL TOULOUSE, FRANCE AB This paper describes the activities of the National Aeronautics and Space Administration's (NASA's) Electrical, Electronic and Electromechanical (EEE) Parts Assurance Group (NEPAG) in its role as a resource sharing and coordinating force in EEE Parts assurance for space flight missions. NEPAG is a new organization, barely two years old. The EEE parts world for space applications faces a number of challenges as we enter the 21(st) Century but the most significant is clearly the economic incorporation of Commercial Off The Shelf (COTS) parts without sacrificing reliability. NEPAG has collaborated in designing a NASA-funded evaluation plan to take a comprehensive look at COTS. A cost/benefit study has been performed to compare the cost of ownership of the US MIL parts NASA has traditionally used with COTS parts screened to an equivalent reliability level. C1 NASA, Goddard Space Flight Ctr, NASA EEE Parts Assurance Grp, Greenbelt, MD 20771 USA. RP Sampson, MJ (reprint author), NASA, Goddard Space Flight Ctr, NASA EEE Parts Assurance Grp, Code 306, Greenbelt, MD 20771 USA. NR 1 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 92-9092-817-4 J9 ESA SP PUBL PY 2002 VL 507 BP 127 EP 136 PG 10 WC Engineering, Aerospace; Computer Science, Hardware & Architecture SC Engineering; Computer Science GA BW32Y UT WOS:000181586400019 ER PT S AU Reschke, MF Kozlovskaya, IB Somers, JT Kornilovaz, LN Paloski, WH Berthoz, A AF Reschke, MF Kozlovskaya, IB Somers, JT Kornilovaz, LN Paloski, WH Berthoz, A BE Warmbein, B TI Smooth pursuit deficits in space flights of variable length SO PROCEEDINGS OF THE EUROPEAN SYMPOSIUM ON LIFE IN SPACE FOR LIFE ON EARTH SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 8th European Symposium on Life Science Research in Space/23rd Annual International Gravitational Physiology Meeting CY JUN 02-07, 2002 CL KAROLINSKA INST, STOCKHOLM, SWEDEN HO KAROLINSKA INST ID HEAD AB The maintenance of stable vision is a primary function of the neurovestibular and sensory-motor systems. There is, re-however, strong evidence suggesting that space flight sults in a modification of the central nervous system and subsequent control of ocular-motor responses. These changes effect those neural mechanisms which are responsible for holding images steady on the retina during brief, self-initiated, head rotations or during the voluntary pursuit of moving targets. Recent studies have shown significant saccadic intrusions in both of these experimental paradigms, including an inability to null the vestibulo-ocular reflex (VOR) during the head/eye pursuit task. The maintenance of vision, while not entirely stable, both inflight and immediately postflight is now believed to be due to neural strategies that evolve for the purpose of assisting in directing the moving target onto the retina. C1 NASA, Lyndon B Johnson Space Ctr, SK, Houston, TX 77058 USA. RP Reschke, MF (reprint author), NASA, Lyndon B Johnson Space Ctr, SK, Houston, TX 77058 USA. RI Kozlovskaya, Inesa/R-9729-2016 NR 7 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 J9 ESA SP PUBL PY 2002 VL 501 BP 57 EP 60 PG 4 WC Biophysics; Physiology SC Biophysics; Physiology GA BW30W UT WOS:000181493800014 ER PT S AU Ronca, AE Baer, LA Wade, CE AF Ronca, AE Baer, LA Wade, CE BE Warmbein, B TI Hypergravity effects on pregnancy and parturition SO PROCEEDINGS OF THE EUROPEAN SYMPOSIUM ON LIFE IN SPACE FOR LIFE ON EARTH SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 8th European Symposium on Life Science Research in Space/23rd Annual International Gravitational Physiology Meeting CY JUN 02-07, 2002 CL KAROLINSKA INST, STOCKHOLM, SWEDEN HO KAROLINSKA INST AB The events of mammalian parturition (labor and birth) were analyzed in Norway rats exposed to either 1.0-g, 1.5-g or 2.0-g hypergravity (hg) beginning at the approximate midpoint of their pregnancies. Pregnant dams were 24h timelapse videorecorded during parturition (days 22-23). Compared with 1-g controls, hg dams displayed one-half as many lordosis contractions, the predominant labor contraction type in rats. The timing of birth, duration of delivery and number of neonates born was comparable in hg and 1-g control dams. Results are discussed in relation to earlier findings that, following spaceflight during pregnancy, lordosis contractions are doubled in frequency. The importance of labor in the transition from prenatal to postnatal life is discussed. Together, these results provide evidence that gravitational load varies inversely with lordosis contraction frequency and support the view that certain biological systems show a continuum of response across gravitational vectors. C1 NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Ronca, AE (reprint author), NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. NR 6 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 J9 ESA SP PUBL PY 2002 VL 501 BP 129 EP 130 PG 2 WC Biophysics; Physiology SC Biophysics; Physiology GA BW30W UT WOS:000181493800043 ER PT S AU Baer, LA Wade, CE Ronca, AE AF Baer, LA Wade, CE Ronca, AE BE Warmbein, B TI Effects of hypergravity exposure on plasma oxytocin concentrations in pregnant and lactating rat dams SO PROCEEDINGS OF THE EUROPEAN SYMPOSIUM ON LIFE IN SPACE FOR LIFE ON EARTH SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 8th European Symposium on Life Science Research in Space/23rd Annual International Gravitational Physiology Meeting CY JUN 02-07, 2002 CL KAROLINSKA INST, STOCKHOLM, SWEDEN HO KAROLINSKA INST AB Rat dams and offspring were exposed to 1.5-g, 1.75-g or 2.0-g hypergravity (hg) from Gestational day [G] 11 until Postnatal day [P] 10. To ascertain the role of maternal factors in reduced postnatal body weights of offspring developed in hg, the dams' lactational hormones were measured. Oxytocin (OT), the major hormone responsible for milk ejection, was reduced in hg dams whereas prolactin (Prl), involved in milk production, was unchanged. Video analyses of nursing behavior revealed that hg dams spent more time nursing relative to 1-g controls. We hypothesized impaired milk transfer from dam to pup, however pup body weight gains following a discrete suckling episode were comparable across conditions. Changes in lactational hormones and nursing behavior by dams exposed to hg do not account for reduced body masses of their offspring. C1 NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Baer, LA (reprint author), NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 J9 ESA SP PUBL PY 2002 VL 501 BP 131 EP 132 PG 2 WC Biophysics; Physiology SC Biophysics; Physiology GA BW30W UT WOS:000181493800044 ER PT B AU Dempsey, PJ Handschuh, RF Afjeh, AA AF Dempsey, PJ Handschuh, RF Afjeh, AA GP ISIF ISIF TI Spiral bevel gear damage detection using decision fusion analysis SO PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON INFORMATION FUSION, VOL I LA English DT Proceedings Paper CT 5th International Conference on Information Fusion (FUSION 2002) CY JUL 08-11, 2002 CL ANNAPOLIS, MD SP IEEE, Georgia Tech Res Inst, USAF Res Lab, US Dept Defense, Missile Defense Agcy, NAVSEA, Oak Ridge Natl Lab, US DOE, USN, Off Res, AIAA, IEE DE gears; damage detection; vibration; wear debris; data fusion; fuzzy logic AB A diagnostic tool for detecting damage to spiral bevel gears was developed. Two different monitoring technologies, oil debris analysis and vibration, were integrated using data fusion into a health monitoring system for detecting surface fatigue pitting damage on gears. This integrated system showed improved detection and decision-making capabilities as compared to using individual monitoring technologies. This diagnostic tool was evaluated by collecting vibration and oil debris data front fatigue tests performed in the NASA Glenn Spiral Bevel Gear Fatigue Rigs. Data was collected during experiments performed in this test rig when pitting damage occurred. Results show that combining the vibration and oil debris measurement technologies improves the detection of pitting damage on spiral bevel gears. C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP Dempsey, PJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU INT SOC INFORMATION FUSION PI SUNNYVALE PA PO BOX 70188, SUNNYVALE, CA 94086 USA BN 0-9721844-1-4 PY 2002 BP 94 EP 100 PG 3 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BV16Q UT WOS:000178041300013 ER PT B AU Kwiatkowska, EJ Fargion, GS AF Kwiatkowska, EJ Fargion, GS GP ISIF ISIF TI Merger of ocean color information from multiple satellite missions under the NASA SIMBIOS Project Office SO PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON INFORMATION FUSION, VOL I LA English DT Proceedings Paper CT 5th International Conference on Information Fusion (FUSION 2002) CY JUL 08-11, 2002 CL ANNAPOLIS, MD SP IEEE, Georgia Tech Res Inst, USAF Res Lab, US Dept Defense, Missile Defense Agcy, NAVSEA, Oak Ridge Natl Lab, US DOE, USN, Off Res, AIAA, IEE DE remote sensing; ocean color; image data fusion; image processing; wavelets; multiresolution analysis; neural networks; SIMBIOS ID SEAWIFS; DECOMPOSITION; CHLOROPHYLL; MODIS; ERA AB The purpose of data merger activities undertaken by the Sensor Intercomparison and Merger for Biological and Interdisciplinary Studies (STAIBIOS) Project is to create scientific quality ocean color data sets encompassing measurements from multiple satellite missions. To meet this goal, a number of image processing and datafusion methodologies have been developed within the Project Office. A backpropagation neural network has been employed to map ocean color products from one sensor along with attracted ancillary parameters into products from another sensor. This enabled seamless fusion of data from both sensors to improve ocean color daily global coverage. Concurrently, statistical objective analysis has been implemented to validate the neural network approach. Wavelet-based image multiresolution analysis has been used to merge measurements from sensors of different spatial resolutions and also to examine the prospect of enhancing oceanic features in lower resolution imagery through the use of higher resolution data. Finally, a merger of satellite and in situ measurements has been developed. C1 NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, SIMBIOS Project, Greenbelt, MD 20771 USA. RP Kwiatkowska, EJ (reprint author), NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, SIMBIOS Project, Code 970-2, Greenbelt, MD 20771 USA. NR 35 TC 1 Z9 1 U1 0 U2 1 PU INT SOC INFORMATION FUSION PI SUNNYVALE PA PO BOX 70188, SUNNYVALE, CA 94086 USA BN 0-9721844-1-4 PY 2002 BP 291 EP 298 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BV16Q UT WOS:000178041300041 ER PT B AU Le Moigne, J Cole-Rhodes, A Eastman, R El-Ghazawi, T Johnson, K Kaewpijit, S Laporte, N Morisette, J Netanyahu, NS Stone, HS Zavorin, I AF Le Moigne, J Cole-Rhodes, A Eastman, R El-Ghazawi, T Johnson, K Kaewpijit, S Laporte, N Morisette, J Netanyahu, NS Stone, HS Zavorin, I GP ISIF ISIF TI Multiple sensor image registration, image fusion and dimension reduction of earth science imagery SO PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON INFORMATION FUSION, VOL II LA English DT Proceedings Paper CT 5th International Conference on Information Fusion (FUSION 2002) CY JUL 08-11, 2002 CL ANNAPOLIS, MD SP IEEE, Georgia Tech Res Inst, USAF Res Lab, US Dept Defense, Missile Defense Agcy, NAVSEA, Oak Ridge Natl Lab, US DOE, USN, Off Res, AIAA, IEE DE registration; fusion; dimension reduction; wavelet processing; remote sensing; hyperspectral AB The goal of our project is to develop and evaluate image analysis methodologies for use on the ground or on-board spacecraft, particularly spacecraft constellations. Our focus is on developing methods to perform automatic registration and fusion of multisensor data representing multiple spatial, spectral and temporal resolutions, as well as dimension reduction of hyperspectral data. Feature extraction methods such as wavelet decomposition, edge detection and mutual information are combined with feature matching methods such as cross-correlation, optimization, and statistically robust techniques to perform image registration. The approach to image fusion is application-based and involves wavelet decomposition, dimension reduction, and classification methods. Dimension reduction is approached through novel methods based on Principal Component Analysis and Wavelet Decomposition, and implemented on Beowulfs-type parallel architectures. Registration algorithms are tested and compared on several multi-sensor datasets, including one of the EOS Core Sites, the Konza Prairie in Kansas, utilizing four different sensors: IKONOS, Landsat-7/ETM+, MODIS, and SeaWIFS. Fusion methods are tested using Landsat, MODIS and SAR or JERS data. Dimension reduction is demonstrated on AVIRIS hyperspectral data. C1 NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Le Moigne, J (reprint author), NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. EM lemoigne@backserv.gsfc.nasa.gov NR 22 TC 1 Z9 1 U1 0 U2 1 PU INT SOC INFORMATION FUSION PI SUNNYVALE PA PO BOX 70188, SUNNYVALE, CA 94086 USA BN 0-9721844-2-2 PY 2002 BP 999 EP 1006 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Remote Sensing SC Computer Science; Remote Sensing GA BV19H UT WOS:000178107500036 ER PT B AU Lyon, RG Dorband, J Solyar, G Ranawake, U AF Lyon, RG Dorband, J Solyar, G Ranawake, U GP ISIF ISIF TI Interferometric image fusion: Interferometry in space SO PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON INFORMATION FUSION, VOL II LA English DT Proceedings Paper CT 5th International Conference on Information Fusion (FUSION 2002) CY JUL 08-11, 2002 CL ANNAPOLIS, MD SP IEEE, Georgia Tech Res Inst, USAF Res Lab, US Dept Defense, Missile Defense Agcy, NAVSEA, Oak Ridge Natl Lab, US DOE, USN, Off Res, AIAA, IEE DE imaging interferometry; optical systems; wavefront sensing; algorithms; control systems; formation flying AB Image fusion and information extraction from multiple spacecraft can occur after each image is sampled and digitized. A more tantalizing, but difficult, approach would be to optically phase multiple spacecraft flying in formation. Phasing of multiple spacecraft allows for coherent addition of imagery resulting in an optical system with a synthetic aperture as large as distance between the spacecraft. Thus, space based optical imaging systems approaching 100's of meters could theorectically be achieved; ultimately allowing for resolution of the solar disks of stars and resolution of extra-solar planets around these stars. The methods and techniques for systems of this type, as well as a number of optical testbeds for proof of principle and validation of the methods are currently under study at NASA Goddard Space Flight Center. In this work we give an overview of the underlying principles, the technology required and the state of development of the various testbeds involved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lyon, RG (reprint author), NASA, Goddard Space Flight Ctr, Code 935, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU INT SOC INFORMATION FUSION PI SUNNYVALE PA PO BOX 70188, SUNNYVALE, CA 94086 USA BN 0-9721844-2-2 PY 2002 BP 1221 EP 1227 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Remote Sensing SC Computer Science; Remote Sensing GA BV19H UT WOS:000178107500066 ER PT S AU Paul, SD AF Paul, SD BE Flury, W SawayaLacoste, H TI NASA JSC trajectory operational support for entry of Space Station Mir SO PROCEEDINGS OF THE INTERNATIONAL WORKSHOP MIR DEORBIT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Mir Deorbit International Workshop CY MAY 14, 2001 CL ESOC, DARMSTADT, GERMANY HO ESOC AB In December 2000, Russian Prime Minister Mikhail Kasyanov signed a decree that announced the Russian plans to safely de-orbit the Mir Space Station. While the Russian government maintained sole responsibility for Mir Space Station de-orbit operations, International assistance was requested to obtain access to additional orbital tracking resources. The United States government, while maintaining its position as an observer of the Mir de-orbit, agreed to provide orbital tracking data from its Space Surveillance network (SSN) to the degree possible. The National Aeronautics and Space Administration (NASA) was requested and agreed to coordinate this support due to the strong working relationship and communications channels developed between NASA and Russian Trajectory organizations for the International Space Station (ISS) Program. Additionally, NASA trajectory specialists at Johnson Space Center performed independent orbit decay assessments and re-entry analyses for the Mir de-orbit scenarios. C1 Barrios Technol Inc, NASA Johnson Space Ctr, Flight Design & Dynam Div, Houston, TX 77058 USA. RP Paul, SD (reprint author), Barrios Technol Inc, NASA Johnson Space Ctr, Flight Design & Dynam Div, Mail Code DM33,2101 NASA Rd 1, Houston, TX 77058 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 92-9092-808-5 J9 ESA SP PUBL PY 2002 VL 498 BP 43 EP 45 PG 3 WC Engineering, Aerospace SC Engineering GA BW36T UT WOS:000181753300005 ER PT S AU Mrozinski, RB AF Mrozinski, RB BE Flury, W SawayaLacoste, H TI NASA pre-event debris footprint estimates for the deorbit of Space Station Mir SO PROCEEDINGS OF THE INTERNATIONAL WORKSHOP MIR DEORBIT SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Mir Deorbit International Workshop CY MAY 14, 2001 CL ESOC, DARMSTADT, GERMANY HO ESOC AB This paper details a method used by the National Aeronautics and Space Administration (NASA) Johnson Space Center to estimate the size and location of the debris footprint expected from the entry and breakup of the Mir Space Station, and results of this method obtained prior to the event. The method estimates the length (range), width (crossrange), and location of debris splashdown and breakup footprints. The method utilizes a three degree-of-freedom Monte Carlo simulation incorporating uncertainties in all aspects of the problem, including vehicle and environment uncertainties. The method incorporates a range of debris characteristics based on historical data in addition to any vehicle-specific debris catalog information. C1 NASA Johnson Space Ctr, Flight Design & Dynam Div, Houston, TX 77058 USA. RP Mrozinski, RB (reprint author), NASA Johnson Space Ctr, Flight Design & Dynam Div, Mail Code DM4 2101 NASA Rd 1, Houston, TX 77058 USA. NR 17 TC 0 Z9 0 U1 1 U2 2 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-808-5 J9 ESA SP PUBL PY 2002 VL 498 BP 47 EP 57 PG 11 WC Engineering, Aerospace SC Engineering GA BW36T UT WOS:000181753300006 ER PT S AU Rutledge, PJ Stamatelatos, MG Chandler, FT Moyer, RW AF Rutledge, PJ Stamatelatos, MG Chandler, FT Moyer, RW BE Battrick, B Preyssl, C TI The NASA risk management program SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB This paper will describe NASA's vision and mission, and how NASA's risk management program has and will continue to contribute to the successful achievement of these goals. It will review the origins and accomplishments of the first five years of NASA's risk management program, its current status, and its future direction. The program began as a NASA Carnegie Mellon Software Engineering Institute joint development project focused on creating a customized "Continuous Risk Management" (CRM) training course for NASA. As a part of this effort, requirements consistent with the training were incorporated in NASA's top-level program, project management procedures, and guidelines. To date, CRM training has been administered by an agency-wide network of "certified" instructors to numerous project teams, including nearly 2000 participants. Across the agency, NASA programs and projects are implementing risk management. The need to use CRM has been reinforced by the Mars 1998 mission failures and other studies. Recently, a strategic alliance between NASA safety and mission assurance and procurement communities has resulted in changes to NASA's supplement to the Federal Acquisition Regulations, enabling earlier, risk-based acquisition management. The NASA Administrator has placed major impetus on improving the risk identification and risk analysis steps of risk management by emphasizing tools and methodologies including fault tree analysis (FTA), failure modes and effects analysis (FMEA), and probabilistic risk assessment (PRA). The implementation of risk management in NASA is periodically verified and validated through a number of formal review mechanisms. The paper will expand on all of the preceding. C1 NASA Headquarters, Off Safety & Mission Assurance, Enterprise Safety & Mission Assurance Div, Washington, DC 20546 USA. RP Rutledge, PJ (reprint author), NASA Headquarters, Off Safety & Mission Assurance, Enterprise Safety & Mission Assurance Div, Code QE,300 E St SW, Washington, DC 20546 USA. NR 3 TC 0 Z9 0 U1 1 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 11 EP 16 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400001 ER PT S AU Stamatelatos, MG Rutledge, PJ AF Stamatelatos, MG Rutledge, PJ BE Battrick, B Preyssl, C TI Probabilistic risk assessment at NASA and plans for the future SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB Many techniques used in probabilistic risk assessment (PRA) originated in the aerospace industry yet this industry currently lags behind others in the use of and contribution to the advance of PRA methods. Over the past decade, NASA has increased its appreciation and use of PRA but, not until recently, has NASA made PRA a programmatic priority. Currently, NASA is aggressively expanding the use of PRA in its programs and projects and is enhancing its in-house expertise in PRA to support engineering and management decisions. Important recent NASA accomplishments in this area include: (1) development of a policy implementation guideline for the use of PRA in programs and projects; (2) development of an integrated PRA software application (QRAS); (3) PRA awareness training for management and PRA methodology courses for practitioners; (4) training on state-of-the-art PRA software; (5) development of a PRA procedures guide for aerospace applications; (6) PRA workshops and conferences; (7) PRA cooperative efforts with US government agencies experienced in PRA (e.g., the Nuclear Regulatory Commission); and (8) PRA cooperative efforts with the European and Japanese space agencies on risk assessment and management. NASA is determined to become a leader in PRA methodology and in its application as an engineering and management tool to improve safety and productivity and to ensure mission success. C1 NASA Headquarters, OSMA, Risk Assessment Program, Washington, DC 20546 USA. RP Stamatelatos, MG (reprint author), NASA Headquarters, OSMA, Risk Assessment Program, 300 E St SW, Washington, DC 20546 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 21 EP 29 PG 9 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400003 ER PT S AU Newman, JS Wander, SM Vantine, W Benfield, P AF Newman, JS Wander, SM Vantine, W Benfield, P BE Battrick, B Preyssl, C TI Introducing the NASA process based mission assurance knowledge management system (PBMA-KMS) SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB Recurrent and costly aerospace system failures and the challenge to define knowledge-based approaches to systems engineering and mission assurance functions are two fundamental drivers behind the evolution of the PBMA-KMS. In response to these challenges, and taking advantage of advances in computer and information management technology, the NASA Office of Safety and Mission Assurance (OSMA) began development of the PBMA-KMS in mid 1999. The PBMA-KMS web site became operational in March 2001. The PBMA-KMS is a user-friendly, web-based resource designed to support life-cycle safety and mission success management. This paper describes the PBMA-KMS functionality, operation, and plans for future growth. C1 NASA Headquarters, Washington, DC 20546 USA. RP Newman, JS (reprint author), NASA Headquarters, 300E St,SW,Code QE, Washington, DC 20546 USA. NR 7 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 39 EP 48 PG 10 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400005 ER PT S AU Newman, JS AF Newman, JS BE Battrick, B Preyssl, C TI The X-framework for space system failure analysis vulnerability assessment & organizational learning SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA C1 NASA Headquarters, Off Safety & Mission Assurance, Washington, DC 20546 USA. RP Newman, JS (reprint author), NASA Headquarters, Off Safety & Mission Assurance, 300E St,SW,Code QE, Washington, DC 20546 USA. NR 17 TC 0 Z9 0 U1 0 U2 2 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 49 EP 59 PG 11 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400006 ER PT S AU Tadlock, DE AF Tadlock, DE BE Battrick, B Preyssl, C TI Avionics safety SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB The avionics safety presentation for the Joint ESA-NASA Space Flight Safety Conference will address the use of electronic or electrical circuitry to manage or control a hazard or potentially hazardous condition or payload function. The briefing will address relevant reference documents and their interpretation, as well as the lessons learned from the review of unclassified payloads from 1980 until the present. The briefing will address the specific requirements of a payload safety package to adequately support the avionics safety review. C1 NASA, Lyndon B Johnson Space Ctr, Avion Syst Div, Houston, TX 77058 USA. RP Tadlock, DE (reprint author), NASA, Lyndon B Johnson Space Ctr, Avion Syst Div, Mail Code EV15, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 75 EP 80 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400009 ER PT S AU Bragg, BJ AF Bragg, BJ BE Battrick, B Preyssl, C TI JSC-EP5 safety philosophy for use of COTS cells/batteries SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Bragg, BJ (reprint author), NASA, Lyndon B Johnson Space Ctr, NASA Rd 1,Mail Code EPS, Houston, TX 77058 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 95 EP 98 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400012 ER PT S AU Shishko, R AF Shishko, R BE Battrick, B Preyssl, C TI Risk analysis simulation of rover operations for Mars surface exploration SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB Risk management advocates have long sought to directly influence the early stages of the systems engineering process through a more effective role in system design trade studies. The principal obstacle to this has been the lack of credible ways to represent and quantify mission risk-that is, a combination of the probability of mission success ("system safety") and science value-for the project manager and the rest of the design team. If it were possible to quantify mission risk, then the effects of proposed mission and system design changes could be calculated, and along with life-cycle costs, could be used to explore the design space more extensively and select better designs. JPL has been working to build the capability to quantify the probability of mission success using a federation of diverse simulations and models, each of which contributes some vital piece of the puzzle. The initial institutional focus has been on Mars surface operations. This ensemble computing framework enables the diverse models and simulations to work together seamlessly. Recent work at JPL has demonstrated the capability to exercise this ensemble from end-to-end using an Oracle-based database to automatically move results from one model/simulation to the next stage in the analysis. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shishko, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 135 EP 143 PG 9 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400018 ER PT S AU Lee, AT AF Lee, AT BE Battrick, B Preyssl, C TI Quantative software risk assessment SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB To quantitatively measure software is a challenge since software is not as visible as hardware. The speaker created a risk model for critical flight software and ground test facilities. The model presents a quantitative approach to assess the software's quality, test efficiency, and functional criticality. The model quantitatively measures the software down to the module level, and derives a risk index to present the module's risk level. The risk index provides a quick reference for project managers to understand the status of the software quality, so to determine the budget and schedule more accurately prior to delivery. The risk index also provides the developers and testers with insight of where the problems are, and what cause the problems. With this approach, unnecessary testing was eliminated, test planning was more effective; and the risk index along with the measurements of the composite elements served as a useful tool for managing schedule and budget risk as well as allowing the designers and testers to focus on improvement areas and mitigating risks. In addition, the application of the model can promote the Capability Maturity Level of the software to levels 4 and 5. It can be used throughout the software development life cycle phases. C1 NASA, Lyndon B Johnson Space Ctr, Safety Reliabil & Qual Assurance Off, Houston, TX 77058 USA. RP Lee, AT (reprint author), NASA, Lyndon B Johnson Space Ctr, Safety Reliabil & Qual Assurance Off, 2101 NASA Rd 1, Houston, TX 77058 USA. NR 14 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 183 EP 189 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400024 ER PT S AU Wetherholt, MS Penix, JJ AF Wetherholt, MS Penix, JJ BE Battrick, B Preyssl, C TI System software safety - Today's practical approach vs. tomorrow's promise SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB Software's flexibility, changeability, and potential for applications yet-to-be-dreamed-of can also be its downfall, especially in regard to safety. We have no choice in this day and age; to accomplish the missions we envision, we must rely on software. Software is being created today that will control critical applications making decisions that can affect the life and death of our crew and vehicles. What analyses, processes, techniques and tools can we use to improve the safety of software, and what tools and techniques should we be developing for the future? This paper attempts to survey the current state of the practice, and provide some insights into what we need to begin preparing for the future. C1 NASA, Off Safety & Mission Assurance, Washington, DC 20546 USA. RP Wetherholt, MS (reprint author), NASA, Off Safety & Mission Assurance, Code Q5, Washington, DC 20546 USA. NR 0 TC 1 Z9 1 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 191 EP 198 PG 8 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400025 ER PT S AU Brekke, M Hartman, D AF Brekke, M Hartman, D BE Battrick, B Preyssl, C TI Payload integration and safety process overview SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB This presentation overviews the payload integration process with focus on the payload safety process. NASA has designed a payload integration process to assure the successful and safe integration and operation of payloads. Payloads that are operated on the Space Shuttle, as well as those that are operated on the Space Station, use the same payload safety process. This process and its relationship to programmatic milestones and events of the payload integration process will be reviewed. In addition, the roles and responsibilities of the customer as well as Space Shuttle and Space Station Program representatives will be discussed. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Brekke, M (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 2 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 221 EP 234 PG 14 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400029 ER PT S AU Flippen, AA Navarro, RJ Larsen, AM Stamatelatos, M AF Flippen, AA Navarro, RJ Larsen, AM Stamatelatos, M BE Battrick, B Preyssl, C TI The prudent application of Probabilistic Risk Assessment to habitable payloads: Utilization of risk-based and traditional rule-based methodologies - A "first" for NASA SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB The safety of the public, astronauts, the workforce, other payloads, the environment, and national resources under its charge are NASA's priorities when assessing the adequacy of space flight designs. While Probabilistic Risk Assessment (PRA) has been successfully applied to Space Shuttle and Space Station vehicle risk decision-making, the mandated use of a non-probabilistic rule-based approach is unique to the safety certification of NASA's habitable payloads. A 1997 survey of historical safety policies with NASA's Payload Safety Review Panel (PSRP) revealed that the non-probabilistic approach for habitable payloads was not arbitrary but founded on informed risk decisions from 20 years ago by then NASA Headquarters policy makers. Based on a sound payload safety track record, there has been no compelling reason, until recently, to consider expanding from the present NSTS 17003 rule-based approach to include risk-based PRA as a viable alternative. However, with the Agency's increased focus on structured risk management, the establishment of a Risk Assessment Program at NASA Headquarters, and refined PRA guidelines and techniques, PRA is now formally recognized as an essential method for evaluating complex and high risk systems. The PSRP recognizes a growing need and an opportunity for evaluating the efficacy of risk-based PRA methods for application to increasingly complex next generation payload technologies. Therefore, it is timely to revisit the potential application of PRA to habitable payloads. This paper discusses PRA as a risk-based method that, when properly implemented, will result in equivalent or improved safety compared with the rule-based failure tolerance requirements for achieving the Agency's "Safety First" core value. The benefits and cautions associated with infusing PRA methodology into the PSRP safety certification process are also discussed, as well as a proposed deployment strategy of how PRA might be prudently tailored and applied to habitable payloads. The use of PRA for assessing payload reliability is unrestricted at NASA but this is beyond the scope of the present discussion of payload safety applications. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Flippen, AA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 7 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 279 EP 285 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400035 ER PT S AU Robinson, F AF Robinson, F BE Battrick, B Preyssl, C TI Risk-based acquisition management process and implementation SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB This paper will introduce the Risk Based Acquisition Management (RBAM) process from the conceptualization to today's current status of implementation. RBAM was developed as a NASA Headquarters initiative aimed at highlighting risk as a core concern during acquisition lifecycle phases. The goals of this initiative are to identify significant risk areas associated with a procurement and focus acquisition team resources to mitigate identified risks. RBAM integrates the analysis of programmatic risk with the formulation of acquisition strategies by overlaying the Agency's Continuous Risk Management process onto the acquisition process. RBAM's program metric goal is to equip Safety and Mission Assurance, Project, and Procurement personnel with methodologies for applying Continuous Risk Management (CRM) principles and Six Sigma Technologies to the NASA acquisition process. The Risk Management Philosophy of Identify, Analyze, Plan, Track, and Control was not only utilized within the acquisition phases to process and mitigate risk, but was employed as the driving 'method of action' throughout the whole process. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Robinson, F (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpk Rd,Mail Stop 50-4, Cleveland, OH 44135 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 287 EP 290 PG 4 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400036 ER PT S AU Safie, FM Maggio, G AF Safie, FM Maggio, G BE Battrick, B Preyssl, C TI The quantitative safety and reliability approach for NASA'S second generation reusable launch vehicles SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB The United States National Aeronautics and Space Administration (NASA) is in the midst of a 10-year Second Generation Reusable Launch Vehicle (RLV) program to improve its space transportation capabilities for both cargo and crewed rnissions. The objectives of the program are to: significantly increase safety and reliability, reduce the cost of accessing low-earth orbit, attempt to leverage commercial launch capabilities, and provide a growth path for manned space exploration. The safety and reliability of the next generation vehicles are major concerns, and NASA aims to achieve orders of magnitude improvement in their safety and reliability compared to today's Space Shuttle system. Achieving these ambitious goals requires a rigorous process that addresses reliability and safety through all the phases of the life cycle of the program. This paper discusses the process being implemented to support achieving the Second Generation program goals/requirements during the conceptual architecture definition phases. Special focus is given to an innovative new tool being used to identify promising technologies that will improve the safety of advanced launch vehicle systems, as well, as assessing the relative merits of proposed architectures. Additionally, discussion focuses on NASA's systems engineering process as it relates to reliability, maintainability, and supportability (RMS). C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Safie, FM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 7 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 307 EP 312 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400039 ER PT S AU Perera, JS AF Perera, JS BE Battrick, B Preyssl, C TI Risk management for the International Space Station SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Perera, JS (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 339 EP 344 PG 6 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400044 ER PT S AU Duarte, A AF Duarte, A BE Battrick, B Preyssl, C TI Risk management implementation program SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB The U.S. civil aerospace program has been a great contributor to the creation and implementation of techniques and methods to identify, analyze, and confront risk. The National Aeronautics and Space Administration (NASA) has accomplished mission success in many instances, but also has experienced failures. Anomalies have kept the Agency from achieving success on other occasions, as well. While NASA has mastered ways to prevent risks, and to quickly and effectively react and recover from anomalies or failures, it was not until few years ago that a comprehensive Risk Management (RM) process started being implemented in some of its programs and projects. A Continuous Risk Management (CRM) cycle process was developed and has been promoted and used successftilly in programs and projects across the Agency. The Space Transportation Directorate at NASA's Marshall Space Flight Center has been a strong advocate of this process. In January 2000, the RM implementation process started and was made available extensively to all programs and projects within the Directorate. The RM Operations Office, reporting to the Director, was created. A plan and definition of general guidelines were presented and discussed with the Director and the program and project managers. A teams training program and related NASA standards training and familiarization were defined and implemented. The RM Toolbox was installed on an internal site through the World Wide Web, which is available to all the Directorate's personnel. The Toolbox includes: an RM template, tools and techniques (fault tree analysis, failure mode and effect analysis, probabilistic risk assessment, hazard analysis, etc.), links to key standards and NASA investigation reports, and lesson's learned, as well as other useful references and documents. Having a series of programs and projects in different points of their life cycles, it was quite challenging to keep them all on track. Risk identification, analysis, planning, tracking, control, and communication/ documentation are the basic steps of the CRM process, which has been successfully implemented within the Directorate. Comprehensive utilization of algorithms, RM grids, risk mitigation waterfall charts, stoplights, etc., and efficient periodic technical and programmatic management reviews of top issues, have enhanced the health and performance of programs and projects. Implementation of CRM is now required for all new programs and projects, and it has been gradually and successfully extended to existing ones. CRM has been included within the top 10 actions listed in the Directorate's Strategic Plan. The ultimate goal is to have the CRM process as an integral part of program and project management to enhance overall mission success. C1 NASA, Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. RP Duarte, A (reprint author), NASA, Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 377 EP 383 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400049 ER PT S AU Harper, JT AF Harper, JT BE Battrick, B Preyssl, C TI Systems safety and the project manager's project SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB Most project managers that are engaged for the first time in designing and fabricating experiment hardware that is intended for space flight on a manned vehicle, are not familiar with the concepts of Systems Safety and the major impact the safety requirements related to manned space flight can have on their project. These requirements go beyond those that are normally associated with experiment performance in the space environment. The basic concepts of Systems Safety, and how they must be incorporated into the hardware design and fabrication effort in order to comply with these requirements will be explained. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harper, JT (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 1 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 421 EP 425 PG 5 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400055 ER PT S AU Cissom, RD Horvath, TJ Watson, KS AF Cissom, RD Horvath, TJ Watson, KS BE Battrick, B Preyssl, C TI The implementation of payload safety in an operational environment SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB The objective of this paper is to define the safety life-cycle process for a payload beginning with the output of the Payload Safety Review Panel and continuing through the life of the payload on-orbit. It focuses on the processes and products of the operations safety implementation through the increment preparations and real-time operations processes. In addition, the paper addresses the role of the Payload Operations and Integration Center and the interfaces to the International Partner Payload Control Centers. C1 NASA, George C Marshall Space Flight Ctr, FPD, Huntsville, AL 35812 USA. RP Cissom, RD (reprint author), NASA, George C Marshall Space Flight Ctr, FPD, Huntsville, AL 35812 USA. NR 2 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 429 EP 433 PG 5 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400056 ER PT S AU Childress, JM Knutson, DL AF Childress, JM Knutson, DL BE Battrick, B Preyssl, C TI Use of crew training to control an International Space Station (ISS) payload hazard SO PROCEEDINGS OF THE JOINT ESA-NASA SPACE-FLIGHT SAFETY CONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-NASA Space-Flight Safety Conference CY JUN 11-14, 2002 CL NOORDWIJK, NETHERLANDS SP European Space Agcy, NASA AB This paper describes the process that is to be followed when crew training is proposed as an operations control of an ISS payload hazard. The paper will address crew training in relation to its acceptability as a hazard control and the requirements imposed on the payload organization to ensure the applicability of the training. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Childress, JM (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 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 92-9092-785-2 J9 ESA SP PUBL PY 2002 VL 486 BP 439 EP 440 PG 2 WC Automation & Control Systems; Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA BV70S UT WOS:000179854400058 ER PT S AU Charnley, SB AF Charnley, SB BE Lacoste, H TI Interstellar chemistry & cometary organic polymers SO PROCEEDINGS OF THE SECOND EUROPEAN WORKSHOP ON EXO-ASTROBIOLOGY SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 2nd European Workshop on Exo/Astrobiology CY SEP 16-19, 2002 CL GRAZ, AUSTRIA SP Austrian Aerosp, Austrian Space Agcy, Cambridge Univ Press, City Graz, European Exo Astrobiol Network Assoc, European Space Agcy, Fachverband Maschinen & Stahlbauindust, Fed Minist Educ, Sci & Culture, Fed Minist Transport, Innovat & Technol, Kluwer Acad Publ, Mary Ann Liebert Inc, Nat Publ Grp, Osterreich Forsch Gemeinsch, Province Styria, Raiffeisenlandesbank Steiermark, Salinen Austria, Springer Publ House, Univ Graz DE astrochemistry; molecular clouds; comets ID ICE ANALOGS; HALE-BOPP; MOLECULES; PHOTOLYSIS; ORIGIN; WATER; HCN AB The connection between the organic polymers believed to exist in cometaxy material and their possible interstellar precursors is discussed. C1 NASA, Ames Res Ctr, Stanford, CA 94305 USA. RP Charnley, SB (reprint author), NASA, Ames Res Ctr, MS 245-3, Stanford, CA 94305 USA. RI Charnley, Steven/C-9538-2012 NR 34 TC 1 Z9 1 U1 1 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-828-X J9 ESA SP PUBL PY 2002 VL 518 BP 33 EP 36 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BW52U UT WOS:000182317000006 ER PT S AU Bailey, S Landis, G Raffaelle, R AF Bailey, S Landis, G Raffaelle, R BE Wilson, A TI The next-generation of space cells for diverse environments SO PROCEEDINGS OF THE SIXTH EUROPEAN SPACE POWER CONFERENCE (ESPC) SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 6th European Space Power Conference (ESPC) CY MAY 06-10, 2002 CL OPORTO, PORTUGAL SP European Space Agcy, Univ Porto, Fac Engenharia, EFACEC, Sistemas Electr SA ID SOLAR-CELLS; MARS AB Future science, military and commercial space missions are incredibly diverse. Military and commercial missions range from large arrays of hundreds of kilowatt to small arrays of ten watts in various Earth orbits. While science missions also have small to very large power needs there are additional unique requirements to provide power for near-sun missions and planetary exploration including orbiters, landers and rovers both to the inner planets and the outer planets with a major emphasis in the near term on Mars. These mission requirements demand cells for low intensity, low temperature applications, high intensity, high temperature applications, dusty environments and often high radiation environments. This paper discusses mission requirements, the current state of the art of space solar cells, and a variety of both evolving thin-film cells as well as new technologies that may impact the future choice of space solar cells for a specific mission application. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Rochester Inst Technol, Dept Phys, Rochester, NY 14623 USA. RP Bailey, S (reprint author), NASA, Glenn Res Ctr, MS 302-1, Cleveland, OH 44135 USA. NR 16 TC 2 Z9 2 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 92-9092-812-3 J9 ESA SP PUBL PY 2002 VL 502 BP 9 EP 15 PG 7 WC Engineering, Aerospace; Electrochemistry; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BU53K UT WOS:000176274600002 ER PT S AU Surampudi, S Mondt, JF Nesmith, BJ Rapp, D AF Surampudi, S Mondt, JF Nesmith, BJ Rapp, D BE Wilson, A TI Advanced radioisotope power system technology development for NASA missions 2011 and beyond SO PROCEEDINGS OF THE SIXTH EUROPEAN SPACE POWER CONFERENCE (ESPC) SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 6th European Space Power Conference (ESPC) CY MAY 06-10, 2002 CL OPORTO, PORTUGAL SP European Space Agcy, Univ Porto, Fac Engenharia, EFACEC, Sistemas Electr SA AB NASA's Office of Space Science requested JPL to lead an assessment of advanced power technologies to enable future NASA Space Science missions. This paper summarizes the result of reviewing the power requirements for future NASA deep space and Mars science missions and providing a technical assessment of candidate advanced radioisotope power system (ARPS) technologies for these missions, including technology road maps. Uncertainties in the lifetime performance of ARPS conversion technologies as well as in the future supply of Pu-238 dictate that several technologies need to be further developed before selecting the optimal one for implementation. It is recommended that the Advanced Stirling Engine Converter (ASEC), Alkali Metal Thermal to Electric Converter (AMTEC) and Segmented Thermoelectric Converter (STEC) technologies be funded with continuation based on yearly detailed technical progress reviews. Selection of an optimum conversion technology would be based on demonstrated technical progress towards meeting NASA's future mission requirements for deep space science missions beyond 2011. C1 Jet Prop Lab, Pasadena, CA 91009 USA. RP Surampudi, S (reprint author), Jet Prop Lab, MS 277-207,4800 Oak Grove Dr, Pasadena, CA 91009 USA. NR 1 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 92-9092-812-3 J9 ESA SP PUBL PY 2002 VL 502 BP 291 EP 296 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BU53K UT WOS:000176274600044 ER PT S AU Thompson, WT AF Thompson, WT BE Wilson, A TI EUV irradiance variations measured with the SOHO coronal diagnostic spectrometer over 4 years of solar cycle 23 SO PROCEEDINGS OF THE SOHO 11 SYMPOSIUM ON FROM SOLAR MIN TO MAX: HALF A SOLAR CYCLE WITH SOHO SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO-11 Symposium on From Solar Min to Max CY MAR 11-15, 2002 CL DAVOS, SWITZERLAND SP Physikalisch Meterolog Observ Davos, World Radiat Ctr DE EUV; irradiance; SOHO; CDS ID MODEL AB The Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory observes the solar EUV spectrum in two bands between 308-379 Angstrom and 513-633 Angstrom, spanning the temperature range from 3 x 10(4) K to 2.7 x 10(6) K. The full Sun irradiance can be measured by rastering the instrument over the solar disk. Measurements of the solar irradiance have been made starting 25 March 1997 and continue to the present, ranging from near solar minimum to solar maximum. This presentation extends earlier work by combining data from both before and after SOHO's accident in 1998. Comparisons are made between the CDS measurements, and predictions from the Hintereggar, EUVAC, EUV97, and SOLAR2000 models. Until the recent launch of the TIMED satellite, these measurements were the only current EUV spectral irradiance measurements taken on a regular basis. The high spectral resolution of these measurements, combined with the coverage of a significant proportion of the solar cycle, provide a unique dataset for understanding solar variability in the EUV. C1 NASA, Goddard Space Flight Ctr, L3 Commun Analyt Corp, Greenbelt, MD 20771 USA. RP Thompson, WT (reprint author), NASA, Goddard Space Flight Ctr, L3 Commun Analyt Corp, Code 682-3, Greenbelt, MD 20771 USA. RI Thompson, William/D-7376-2012 NR 7 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 92-9092-818-2 J9 ESA SP PUBL PY 2002 VL 508 BP 193 EP 196 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU99D UT WOS:000177565200037 ER PT S AU McIntosh, SW AF McIntosh, SW BE Wilson, A TI Conduction in the transition region?: Interpretation of DEMs using SOHO/SUMER observations SO PROCEEDINGS OF THE SOHO 11 SYMPOSIUM ON FROM SOLAR MIN TO MAX: HALF A SOLAR CYCLE WITH SOHO SE ESA Special Publications LA English DT Proceedings Paper CT SOHO-11 Symposium on From Solar Min to Max CY MAR 11-15, 2002 CL DAVOS, SWITZERLAND SP Physikalisch Meterolog Observ Davos, World Radiat Ctr ID ENERGY-BALANCE; SOLAR; TEMPERATURE AB The role of classical heat conduction in the energy balance of the T-e domain of the transition region (10(5) - 10(8) h) is explored. We consider variations in space and time of the Differential Emission Measure (DEM) inferred from high cadence (10s) SUMER observations taken on May 17, 1998 as part of JOP72. In particular, we show that the gradient of the DEM in the observed region, irrespective of the spatial/temporal binning applied, is 3/2. We discuss the implications of this result. C1 NASA, Goddard Space Flight Ctr, ESA Res & Sci Support Dept, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, ESA Res & Sci Support Dept, Mailcode 682-3, Greenbelt, MD 20771 USA. EM scott@esa.nascom.nasa.gov NR 16 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 92-9092-818-2 J9 ESA SPEC PUBL PY 2002 VL 508 BP 271 EP 274 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU99D UT WOS:000177565200052 ER PT S AU Ireland, J Walsh, RW De Moortel, I Moretti, PF AF Ireland, J Walsh, RW De Moortel, I Moretti, PF BE Wilson, A TI Preliminary description of Kanzelhohe/MDI magnetograms and the search for sources of coronal oscillations SO PROCEEDINGS OF THE SOHO 11 SYMPOSIUM ON FROM SOLAR MIN TO MAX: HALF A SOLAR CYCLE WITH SOHO SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO-11 Symposium on From Solar Min to Max CY MAR 11-15, 2002 CL DAVOS, SWITZERLAND SP Physikalisch Meterolog Observ Davos, World Radiat Ctr DE Sun; magnetic field; photosphere; corona ID LOOPS AB Many examples of transverse (Schrijver et al., 2002; Aschwanden et al., 2002) and longitudinal coronal loop oscillations have now been observed in TRACE 171 Angstrom data (see De Moortel et al., 20021) at this meeting for examples of longitudinal oscillations). These oscillations hold the promise of telling us much about the physics of the corona. However, the mechanisms describing these distinct phenomena are as yet unclear. Magnetogram data from MDI and Kanzelhohe taken as part of SOHO Joint Observing Program 144 allows us to use the spatial resolution of MDI and temporal resolution of Kanzelhohe to probe the photospheric magnetic field at likely footpoint sources of coronal loop oscillations at length and time scales not available to either instrument separately. Variations in the photospheric magnetic field are analysed in conjunction with co-temporally observed TRACE 171 Angstrom derived time series. C1 NASA, Goddard Space Flight Ctr, L3Com Analyt Corp, Greenbelt, MD 20771 USA. RP Ireland, J (reprint author), NASA, Goddard Space Flight Ctr, L3Com Analyt Corp, Code 682-3,Bldg 26, Greenbelt, MD 20771 USA. NR 6 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 92-9092-818-2 J9 ESA SP PUBL PY 2002 VL 508 BP 299 EP 302 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU99D UT WOS:000177565200059 ER PT S AU Kucera, TA Tovar, M De Pontieu, B AF Kucera, TA Tovar, M De Pontieu, B BE Wilson, A TI Transverse prominence motions from 10,000-250,000 K SO PROCEEDINGS OF THE SOHO 11 SYMPOSIUM ON FROM SOLAR MIN TO MAX: HALF A SOLAR CYCLE WITH SOHO SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO-11 Symposium on From Solar Min to Max CY MAR 11-15, 2002 CL DAVOS, SWITZERLAND SP Physikalisch Meterolog Observ Davos, World Radiat Ctr AB We address the origin of prominence material by comparing high cadence (30-60 s) He I and O V EUV observations from SOHO/CDS wide slit movies, and also, for another prominence observation, observations from TRACE at 1216 Angstrom and 1600 Angstrom and SVST in Halpha. The EUV and UV observations regularly show small scale structures with plane-of-the-sky velocities of 20-80 km/s. Many, although not all, of these motions are seen in multiple wavelength bands, representing temperatures ranging from 10,000 100,000 K or 20,000 - 250,000 K, depending on the data set. The Ha observations contain line shift information showing clearly that the associated UV prominence intensity motions do actually represent real mass motions, as opposed to temperature or density waves. The results also indicate that the "prominence-corona transition region" is not an outside layer to the prominence as a whole, but is rather associated with smaller scale structures all through the prominence. More work is needed to determine what mechanism can explain these fast, multi-temperature prominence motions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kucera, TA (reprint author), NASA, Goddard Space Flight Ctr, Code 682, Greenbelt, MD 20771 USA. RI Kucera, Therese/C-9558-2012 NR 6 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 92-9092-818-2 J9 ESA SP PUBL PY 2002 VL 508 BP 307 EP 310 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU99D UT WOS:000177565200061 ER PT S AU Gurman, JB AF Gurman, JB BE Wilson, A TI Toward a Virtual Solar Observatory SO PROCEEDINGS OF THE SOHO 11 SYMPOSIUM ON FROM SOLAR MIN TO MAX: HALF A SOLAR CYCLE WITH SOHO SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO-11 Symposium on From Solar Min to Max CY MAR 11-15, 2002 CL DAVOS, SWITZERLAND SP Physikalisch Meterolog Observ Davos, World Radiat Ctr AB NASA is currently engaged in the study phase of a modest effort to establish a Virtual Solar Observatory (VSO). The VSO would serve ground- and space-based solar physics data sets from a distributed network of archives through a small number of interfaces to the: scientific community. The basis of this approach, as of all planned virtual observatories, is the translation of metadata from the various sources via source-specific dictionaries so the user will not have to distinguish among keyword usages. A single Web interface should give access to all the distributed data. We present the current status of the VSO, its initial scope, and its relation to the European EGSO effort. C1 NASA, Goddard Space Flight Ctr, Lab Astron & Solar Phys, Greenbelt, MD 20771 USA. RP Gurman, JB (reprint author), NASA, Goddard Space Flight Ctr, Lab Astron & Solar Phys, Code 661, Greenbelt, MD 20771 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 92-9092-818-2 J9 ESA SP PUBL PY 2002 VL 508 BP 525 EP 530 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU99D UT WOS:000177565200100 ER PT B AU Hebsur, MG AF Hebsur, MG BE Ghosh, A Sanders, TH Claar, TD TI Processing of IN-718 lattice block castings SO PROCESSSING AND PROPERTIES OF LIGHTWEIGHT CELLULAR METALS AND STRUCTURES LA English DT Proceedings Paper CT 3rd Global Symposium on Materials Processing and Manufacturing CY FEB 17-21, 2002 CL Seattle, WA SP ONR AB Recently a low cost casting method known as lattice block casting has been developed by JAM Corp., Wilmington, Massachusetts for engineering materials such as Aluminum and Stainless steels that has shown to provide very high stiffness and strength with only a fraction of the density of the parent alloy. NASA Glenn Research Center has initiated a research to investigate lattice block castings of high temperature Ni-base superalloys such as Inconel-718 (IN-718) for lightweight nozzle applications. Although difficulties were encountered throughout the manufacturing process, a successful investment casting procedure was eventually developed. Wax formulation and pattern assembly, shell mold processing, and counter gravity casting techniques were all developed. Totally ten IN-718 lattice block castings (each measuring 15-cm wide by 30-cm long by 1.2-cm thick) have been successfully produced by Hitchiner Gas Turbine Division, Milford, New Hampshire using their patented counter gravity casting techniques. Details of the processing and resulting microstructures are discussed in this paper. Post casting processing and evaluation of system specific mechanical property of these specimens are in progress. C1 NASA, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Hebsur, MG (reprint author), NASA, Ohio Aerosp Inst, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 2 Z9 3 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-527-1 PY 2002 BP 85 EP 96 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BAW13 UT WOS:000223863600008 ER PT B AU Krause, DL Whittenberger, JD Kantzos, PT Hebsur, MG AF Krause, DL Whittenberger, JD Kantzos, PT Hebsur, MG BE Ghosh, A Sanders, TH Claar, TD TI Mechanical testing of IN718 lattice block structures SO PROCESSSING AND PROPERTIES OF LIGHTWEIGHT CELLULAR METALS AND STRUCTURES LA English DT Proceedings Paper CT 3rd Global Symposium on Materials Processing and Manufacturing CY FEB 17-21, 2002 CL Seattle, WA SP ONR AB Lattice block construction produces a flat, structurally rigid panel composed of thin ligaments of material arranged in a three-dimensional triangulated truss-like structure. Low-cost methods of producing cast metallic lattice block panels are now available that greatly expand opportunities for using this unique material system in today's high-performance structures. Additional advances are being made in NASA's Ultra Efficient Engine Technology (UEET) program to extend the lattice block concept to superalloy materials. Advantages offered by this combination include high strength, light weight, high stiffness and elevated temperature capabilities. Recently under UEET, the nickel-based superalloy Inconel 718 (IN718) was investment cast into lattice block panels with great success. To evaluate casting quality and lattice block architecture merit, individual ligaments and structural subelement specimens were extracted from the panels. Tensile tests and structural compression and bending strength tests were performed on these specimens. This paper first presents metallurgical and optical microscopy analysis of the castings. This is followed by mechanical test results for the tensile ligament tests and the subelement compression and bending strength tests. These tests generally showed comparable properties to base IN718 with the same heat treatment, and they underscored the benefits offered by lattice block materials. These benefits might be extended with improved architecture such as face sheets. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Krause, DL (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 TC 6 Z9 6 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-527-1 PY 2002 BP 233 EP 242 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BAW13 UT WOS:000223863600022 ER PT S AU Kandt, RK AF Kandt, RK BE Oivo, M KomiSirvio, S TI Software configuration management principles and best practices SO PRODUCT FOCUSED SOFTWARE PROCESS IMPROVEMENT, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 4th International Conference on Product Focused Software Process Improvement CY DEC 09-11, 2002 CL ROVANIEMI, FINLAND AB This paper identifies fundamental principles and practices essential to the successful performance of a configuration management system. Practices are grouped into four categories that govern the management process, ensure product quality, protect software artifacts, and guide tool use. In addition, the practices are prioritized according to their effect on software products and processes and the coverage of the identified principles. When these practices should be applied in the software development lifecycle is discussed, as is the potential for automating and validating practices. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kandt, RK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 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 3-540-00234-0 J9 LECT NOTES COMPUT SC PY 2002 VL 2559 BP 300 EP 313 PG 14 WC Computer Science, Information Systems; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BW33L UT WOS:000181620800023 ER PT J AU Ryan, JP Polito, PS Strutton, PG Chavez, FP AF Ryan, JP Polito, PS Strutton, PG Chavez, FP TI Unusual large-scale phytoplankton blooms in the equatorial Pacific SO PROGRESS IN OCEANOGRAPHY LA English DT Review ID 1997-98 EL-NINO; TROPICAL INSTABILITY WAVES; SOUTHERN-OSCILLATION EVENT; SEA-SURFACE TEMPERATURE; PRIMARY PRODUCTIVITY; WIND STRESS; OCEAN COLOR; WARM POOL; TOPEX/POSEIDON; VARIABILITY AB Unusual large-scale accumulations of phytoplankton occurred across 10,000 km of the equatorial Pacific during the 1998 transition from El Nino to La Nina. The forcing and dynamics of these phytoplankton blooms were studied using satellite-based observations of sea surface height, temperature and chlorophyll, and mooring-based observations of winds, hydrography and ocean currents. During the bloom period, the thermocline (nutricline) was anomalously shallow across the equatorial Pacific. The relative importance of processes that enhanced nutrient flux into the euphotic zone differed between the western and eastern regions of the blooms. In the western bloom region, the important vertical processes were turbulent vertical mixing and wind-driven upwelling. In contrast, the important processes in the eastern bloom region were wave-forced shoaling of nutrient source waters directly into the euphotic zone, along-isopycnal upwelling, and wind-driven upwelling. Advection by the Equatorial Undercurrent spread the largest bloom 4500 km east of where it began, and advection by meridional currents of tropical instability waves transported the bloom hundreds of kilometers north and south of the equator. Many processes influenced the intricate development of these massive biological events. Diverse observations and novel analysis methods of this work advance the conceptual framework for understanding the complex dynamics and ecology of the equatorial Pacific. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. NASA, Jet Prop Lab, Pasadena, CA USA. RP Ryan, JP (reprint author), Monterey Bay Aquarium Res Inst, 7700 Sandholdt Rd, Moss Landing, CA 95039 USA. EM ryjo@mbari.org RI Polito, Paulo/F-3040-2013; Strutton, Peter/C-4466-2011 OI Polito, Paulo/0000-0003-2217-3853; Strutton, Peter/0000-0002-2395-9471 NR 54 TC 51 Z9 52 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6611 J9 PROG OCEANOGR JI Prog. Oceanogr. PY 2002 VL 55 IS 3-4 BP 263 EP 285 AR PII S0079-6611(02)00137-4 DI 10.1016/S0079-6611(02)00137-4 PG 23 WC Oceanography SC Oceanography GA 632EK UT WOS:000180210600001 ER PT J AU Peterson, WT Keister, JE Feinberg, LR AF Peterson, WT Keister, JE Feinberg, LR TI The effects of the 1997-99 El Nino/La Nina events on hydrography and zooplankton off the central Oregon coast SO PROGRESS IN OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Workshop on El Nino Along the West Coast of North America CY DEC 06-09, 1999 CL MOSS LANDING, CALIFORNIA DE El Nino; nutrients; chlorophyll; copepod community structure; Pseudocalanus; Calanus ID COMMUNITY STRUCTURE; COPEPOD COMMUNITY; BRITISH-COLUMBIA; CALIFORNIA; MEXICO AB Hydrographic data and nutrient, chlorophyll and zooplankton samples were collected biweekly at a hydrographic station off Newport, Oregon during the 1997-98 El Nino and 1998-99 La Nina event. Our monitoring in 1997 showed that coastal upwelling was initiated in April, the usual time. However, a series of southwesterly storms in May and June 1997 led to a prolonged warming event and reductions in copepod biomass. Though El Nino-driven atmospheric teleconnections might have been responsible for these storms, the coastal ecosystem returned to normal with the resumption of coastal upwelling in mid-July 1997. A downwelling event began on 20 August 1997 resulting in onshore movement of offshore waters. This event appeared to mark the passage of the first Kelvin wave. At this time the shelf became flooded with low-nutrient waters and offshore, 'warm-water' copepod species were transported shoreward. The abundance of local endemic boreal neritic copepod species was reduced greatly, presumably because they were transported out of the system and to the north as a result of the strong poleward flows. Poleward flows strengthened during autumn, and the ocean off Oregon remained anomalously warm through the winter of 1997, spring, and early summer of 1998. Species composition of the coastal copepod assemblage remained anomalous for about a year; species with offshore and subtropical affinities dominated from late August 1997 through late July 1998. During this same period, nitrate concentrations were reduced by a factor of 4.5 (11-month mean of 1.5 muM for August 1997-July 1998 versus 6.9 muM for August 1998-July 1999), copepod biomass was reduced by a factor of 2.1 (4.9 mug carbon 1(-1) versus 10.5 for the same time periods), but chlorophyll concentrations were similar (2.0 versus 2.5 mug 1(-1)). Perhaps the most dramatic effect on copepods during the El Nino period was the nearly complete disappearance of the normally dominant boreal neritic copepod species (Pseudocalanus mimus, Calanus marshallae and Acartia longiremis) and their replacement by subtropical species such as Calanus pacificus, Paracalanus parvus, Ctenocalanus vanus, Corycaeus anglicus and several species of Clausocalanus. These species persisted in the coastal waters through the end of 1998. Although most of the subarctic species began to increase in numbers in August 1998, the impact of the El Nino on Pseudocalanus mimus, normally the numerical dominant in coastal waters, was longer lasting. The P. mimus population did not recover to normal abundance levels until summer of 1999. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. RP Peterson, WT (reprint author), Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. RI Keister, Julie/J-8720-2012 OI Keister, Julie/0000-0002-9385-5889 NR 27 TC 84 Z9 84 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6611 J9 PROG OCEANOGR JI Prog. Oceanogr. PY 2002 VL 54 IS 1-4 BP 381 EP 398 AR PII S0079-6611(02)00059-9 DI 10.1016/S0079-6611(02)00059-9 PG 18 WC Oceanography SC Oceanography GA 598ZZ UT WOS:000178308900020 ER PT J AU Peterson, WT Keister, JE AF Peterson, WT Keister, JE TI The effect of a large cape on distribution patterns of coastal and oceanic copepods off Oregon and northern California during the 1998-1999 El Nino-La Nina SO PROGRESS IN OCEANOGRAPHY LA English DT Review ID ZOOPLANKTON; AFRICA; PLANKTON; FILAMENT; CYCLE AB Hydrographic and ocean drifter measurements made along the Oregon coast indicate that the spatial structure of the coastal upwelling system differs in waters to the north and the south of Cape Blanco, Oregon. North of the Cape, a 10-30 km wide zone of coastal upwelling parallels the coast, but south of the Cape, increased wind stress leads to a seaward expansion of the upwelling system and cold upwelled water extends 50-100 km offshore. Because the hydrography and the transport differ, we hypothesize that zooplankton distributions will differ as well. In this paper we investigate differences in copepod distributions and copepod community composition between the waters north and south of Cape Blanco. Five cruises were conducted in 1998 and 1999, which were years of contrasting ocean conditions; there was a strong El Nino in 1998, which was followed by a strong La Nina in 1999. Copepod biomass did not differ between the El Nino and La Nina periods; however, species composition of the copepod assemblages differed vastly. During the 1998 El Nino, the copepod community was dominated by subtropical neritic and warm-water offshore species. During the 1999 La Nina, the zooplankton community was dominated by cold water boreal neritic species. The warm water species were widely distributed in shelf and slope waters in 1998, whereas in 1999, they were found primarily offshore of central Oregon, but over the shelf off northern California. During the summer upwelling season of both years, copepod community composition in shelf waters differed significantly from slope waters in the region to the north of the Cape, however, community composition was the same in shelf and slope waters in the region south of the Cape. These results lead us to suggest that offshore transport by the upwelling jet may be an important mechanism controlling copepod community structure south of Cape Blanco. When we examined these patterns in community composition on a species-by-species basis, among the dominant boreal copepod species, Pseudocalanus mimus and Acartia longiremis were displaced offshore and maintained high population densities in the waters south of Cape Blanco whereas densities of Calanus marshallae and Centropages abdominalis declined in the waters south of the Cape. Thus, the interaction between the boreal copepods and the waters north versus south of Blanco is species-specific. Species may be either lost or retained depending upon interactions between vertical current shear and their vertical distributions. Alternatively, there tray be a differential ability among species to survive and reproduce in waters offshore and south of Cape Blanco. (C) 2002 Published by Elsevier Science Ltd. C1 Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resource Studies, Newport, OR 97365 USA. RP Peterson, WT (reprint author), Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. RI Keister, Julie/J-8720-2012 OI Keister, Julie/0000-0002-9385-5889 NR 26 TC 34 Z9 34 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6611 J9 PROG OCEANOGR JI Prog. Oceanogr. PY 2002 VL 53 IS 2-4 BP 389 EP 411 AR PII S0079-6611(02)00038-1 DI 10.1016/S0079-6611(02)00038-1 PG 23 WC Oceanography SC Oceanography GA 574QF UT WOS:000176900500013 ER PT S AU Masi, S De Bernardis, P De Troia, G Giacometti, M Iacoangeli, A Piacentini, F Polenta, G Ade, PAR Mauskopf, PD Bock, JJ Bond, JR Contaldi, CR Pogosyan, D Prunet, S Borrill, J Boscaleri, A Pascale, E Coble, K Farese, P Montroy, T Ruhl, JE Crill, BP Hristov, VV Jones, WC Lange, AE Mason, P De Gasperis, G Natoli, P Ganga, K Hivon, E Vittorio, N Jaffe, AH Martinis, L Scaramuzzi, F Melchiorri, A Netterfield, CB Pongetti, F Romeo, G AF Masi, S De Bernardis, P De Troia, G Giacometti, M Iacoangeli, A Piacentini, F Polenta, G Ade, PAR Mauskopf, PD Bock, JJ Bond, JR Contaldi, CR Pogosyan, D Prunet, S Borrill, J Boscaleri, A Pascale, E Coble, K Farese, P Montroy, T Ruhl, JE Crill, BP Hristov, VV Jones, WC Lange, AE Mason, P De Gasperis, G Natoli, P Ganga, K Hivon, E Vittorio, N Jaffe, AH Martinis, L Scaramuzzi, F Melchiorri, A Netterfield, CB Pongetti, F Romeo, G BE Faessler, A TI The BOOMERanG experiment and the curvature of the Universe SO PROGRESS IN PARTICLE AND NUCLEAR PHYSICS, VOL 48 NO 1: NEURTRINOS IN ASTRO, PARTICLE AND NUCLEAR PHYSICS SE PROGRESS IN PARTICLE AND NUCLEAR PHYSICS LA English DT Article; Proceedings Paper CT International School of Nuclear Physics CY SEP 18-26, 2001 CL ERICE, ITALY ID MICROWAVE BACKGROUND-RADIATION; COSMOLOGICAL PARAMETERS; ANISOTROPIES; EMISSION; FIRAS; MAPS AB We. describe the BOOMERanG experiment and its main result, i.e. the measurement of the large scale curvature of the Universe. BOOMERanG is a balloon-borne microwave telescope with sensitive cryogenic detectors. BOOMERanG has measured the angular distribution of the Cosmic Microwave Background on similar to 3% of the sky, with a resolution of similar to 10 arcmin and a sensitivity of similar to 20muK per pixel. The resulting image is dominated by hot. and cold spots with rms fluctuations similar to 80muK and typical size of similar to 1degrees. The detailed angular power spectrum of the image features three peaks and two dips at l = (213(-13)(+10)) (541(-32)(+20)) (845(-25)(+12)) and l = (416(-12)(+22)), (750(-750)(+20)), respectively. Such very characteristic spectrum can be explained assurning that the detected structures are the result of acoustic oscillations in the primeval plasma. In this framework, the measured pattern constrains the, density parameter Omega to be 0.85 < Omega < 1.1 (95% confidence interval). Other cosmological parameters, like the spectral index of initial density fluctuations, the density parameter for baryons, dark matter and dark energy, are detected or constrained by the BOOMERanG measurements and by other recent, CMB anisotropy experiments. When combined with other cosmological observations, these results depict a new, consistent,, cosmological scenario. C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Dept Phys & Astron, Cardiff, S Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Toronto, CITA, Toronto, ON, Canada. LBNL, NERSC, Berkeley, CA USA. CNR, IROE, I-50127 Florence, Italy. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Pasadena, CA 91125 USA. Univ Roma Tor Vergata, Dept Phys, Rome, Italy. CALTECH, IPAC, Pasadena, CA 91125 USA. CFPA, Berkeley, CA USA. ENEA, Frascati, Italy. Nucl & Astrophys Lab, Oxford, England. Univ Toronto, Dept Phys & Astron, Toronto, ON, Canada. Ist Nazl Geofis, Rome, Italy. RP Masi, S (reprint author), Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Piacentini, Francesco/E-7234-2010; OI Hivon, Eric/0000-0003-1880-2733; de Gasperis, Giancarlo/0000-0003-2899-2171; Piacentini, Francesco/0000-0002-5444-9327; Masi, Silvia/0000-0001-5105-1439; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Polenta, Gianluca/0000-0003-4067-9196; Melchiorri, Alessandro/0000-0001-5326-6003 NR 45 TC 29 Z9 29 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0146-6410 J9 PROG PART NUCL PHYS PY 2002 VL 48 IS 1 BP 243 EP 261 AR PII S0146-6410(02)00131-X DI 10.1016/S0146-6410(02)00131-X PG 19 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA BU79T UT WOS:000177028400029 ER PT S AU Wang, Y AF Wang, Y BE Wu, MH TI Efficiency enhancement of liquid crystal projection displays using light recycle technology SO PROJECTION DISPLAYS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Projection Displays VIII CY JAN 23-24, 2002 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE DE LCD; color filter; color recycling; display; projector AB A new technology, developed at Jet Propulsion Laboratory (JPL), using low-absorption color filters with polarization and color recycle system, is able to enhance efficiency of a single panel liquid crystal display (LCD) projector to the same efficiency of a three panel LCD projector. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Wang, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 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 0-8194-4397-2 J9 P SOC PHOTO-OPT INS PY 2002 VL 4657 BP 62 EP 66 DI 10.1117/12.463783 PG 5 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BU67N UT WOS:000176683100009 ER PT J AU Unwin, SC Wehrle, AE Jones, DL Meier, DL Piner, BG AF Unwin, SC Wehrle, AE Jones, DL Meier, DL Piner, BG TI Quasar astrophysics with the Space Interferometry Mission SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA LA English DT Article; Proceedings Paper CT White Workshop on AGN Variability Across the Electromagnetic Spectrum CY JUN 25-29, 2001 CL CSIRO ATNF, SYDNEY, AUSTRALIA HO CSIRO ATNF DE galaxies : active; galaxies : jets; techniques : interferometric ID X-RAY; RELATIVISTIC JETS; ACTIVE GALAXIES; REFERENCE-FRAME; M87 JET; RADIO; ACCRETION; EMISSION; MODEL AB Precision optical astrometry of quasars and active galaxies can provide important insight into the spatial distribution and variability of emission in compact nuclei. SIM - the Space Interferometry Mission - will be the first optical interferometer capable of precision astrometry on quasars. Although it is not expected to resolve the emission, it will be very sensitive to astrometric shifts, for objects as faint as R magnitude 20. In its wide-angle mode, SIM will yield 4 microarcsecond absolute positions, and proper motions to about 2 microarcsecond/yr. A variety of AGN phenomena are expected to be visible to SIM on these scales, including time and spectral dependence in position offsets between accretion disk and jet emission. SIM should be able to answer the following questions. Does the most compact optical emission from an AGN come from an accretion disk or from a relativistic jet? Do the relative positions of the radio core and optical photocentre of quasars used for the reference frame tie change on the timescales of their photometric variability? Do the cores of galaxies harbour binary supermassive black holes remaining from galaxy mergers? In this paper we briefly describe the operation of SIM and the quasar measurements it will make. We estimate the size of the astrometric signatures which may be expected, and we discuss prospects for using astrometry as a fundamental tool for understanding quasar nuclei. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA. RP Unwin, SC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 5 Z9 5 U1 0 U2 1 PU C S I R O PUBLISHING PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA SN 1323-3580 J9 PUBL ASTRON SOC AUST JI Publ. Astron. Soc. Aust. PY 2002 VL 19 IS 1 BP 5 EP 9 DI 10.1071/AS01087 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 567JW UT WOS:000176482500002 ER PT J AU Weisskopf, MC Brinkman, B Canizares, C Garmire, G Murray, S Van Speybroeck, LP AF Weisskopf, MC Brinkman, B Canizares, C Garmire, G Murray, S Van Speybroeck, LP TI An overview of the performance and scientific results from the Chandra X-ray Observatory SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Review ID HIGH-RESOLUTION CAMERA; IN-FLIGHT PERFORMANCE; TRANSMISSION GRATING SPECTROMETER; SUPERMASSIVE BLACK-HOLE; FIELD-NORTH AREA; ACCRETION DISK; DEEP SURVEY; CONTAMINATION MONITOR; INITIAL PERFORMANCE; ABSORPTION LINES AB The Chandra X-Ray Observatory (CXO), the X-ray component of NASA's Great Observatories, was launched on 1999 July 23 by the space shuttle Columbia. After satellite systems activation, the first X-rays focused by the telescope were observed on 1999 August 12. Beginning with the initial observation it was clear that the telescope had survived the launch environment and was operating as expected. Despite an initial surprise due to the discovery that the telescope was far more efficient for concentrating CCD-damaging low-energy protons than had been anticipated, the observatory is performing well and is returning superb scientific data. Together with other space observatories, most notably XMM-Newton, it is clear that we have entered a new era of discovery in high-energy astrophysics. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. SRON, NL-3584 CA Utrecht, Netherlands. MIT, Cambridge, MA 02139 USA. Penn State Univ, Davey Lab 525, University Pk, PA 16802 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Weisskopf, MC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 88 TC 443 Z9 444 U1 4 U2 9 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 2002 VL 114 IS 791 BP 1 EP 24 DI 10.1086/338108 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 508ML UT WOS:000173092800001 ER PT J AU Leonard, DC Filippenko, AV Gates, EL Li, WD Eastman, RG Barth, AJ Bus, SJ Chornock, R Coil, AL Frink, S Grady, CA Harris, AW Malkan, MA Matheson, T Quirrenbach, A Treffers, RR AF Leonard, DC Filippenko, AV Gates, EL Li, WD Eastman, RG Barth, AJ Bus, SJ Chornock, R Coil, AL Frink, S Grady, CA Harris, AW Malkan, MA Matheson, T Quirrenbach, A Treffers, RR TI The distance to SN 1999em in NGC 1637 from the expanding photosphere method SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID LARGE MAGELLANIC CLOUD; TELESCOPE KEY PROJECT; OPTICAL LIGHT-CURVE; II SUPERNOVAE; HUBBLE CONSTANT; STANDARD STARS; IA SUPERNOVAE; LINE IDENTIFICATIONS; SPECTRAL-ANALYSIS; CEPHEID DISTANCE AB We present 30 optical spectra and 49 photometric epochs sampling the first 517 days after discovery of supernova (SN) 1999em and derive its distance through the expanding photosphere method (EPM). SN 1999em is shown to be a Type II-plateau (II-P) event, with a photometric plateau lasting until about 100 days after explosion. We identify the dominant ions responsible for most of the absorption features seen in the optical portion of the spectrum during the plateau phase. Using the weakest unblended absorption features to estimate photospheric velocity, we find the distance to SN 1999em to be D=8.2+/-0.6 Mpc, with an explosion date of HJD 2,451,475.6+/-1.4 or 5.3+/-1.4 days before discovery. We show that this distance estimate is about 10% closer than the distance that results if the strong Fe II lambdalambda4924, 5018, 5169 absorption features, which have often been used in previous EPM studies, are used to estimate photospheric velocity. We examine potential sources of systematic error in EPM-derived distances and find the most significant to result from uncertainty in the theoretical modeling of the flux distribution emitted by the SN photosphere (i.e., the "flux dilution factor"). We compare previously derived EPM distances to eight SNe II in galaxies (or members of the same group) for which a recently revised Cepheid distance exists from the Hubble Space Telescope Key Project and find D(Cepheids)/D(EPM) = 0.87+/-0.06 (statistical); eliminating the three SNe II distances for which a Cepheid distance exists only to a group member, and not the host galaxy itself, yields. D(Cepheids)/D(EPM) = 0.96+/-0.09. Additional direct comparisons, especially to spectroscopically and photometrically normal SNe II-P, will certainly help to produce a more robust comparison. Finally, we investigate the possible use of SNe II-P as standard candles and find that for eight photometrically confirmed SNe II-P with previously derived EPM distances and SN 1999em, the mean plateau absolute brightness is (M) over bar (v)(plateau) = -16.4+/-0.6 mag, implying that distances good to similar to30% (1 sigma) may be possible without the need for a complete EPM analysis. At (M) over bar (v)(plateau) = -15.9+/-0.2 mag, SN 1999em is somewhat fainter than the average SN II-P. The general consistency of absolute SNe II-P brightness during the plateau suggests that the standard candle assumption may allow SNe II-P to be viable cosmological beacons at z>2. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Lick Observ, Mt Hamilton, CA 95140 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Hawaii, Inst Astron, Hilo, HI 96720 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, Dept Phys, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Leonard, DC (reprint author), Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. EM leonard@nova.astro.umass.edu NR 99 TC 174 Z9 174 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 2002 VL 114 IS 791 BP 35 EP 64 DI 10.1086/324785 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 508ML UT WOS:000173092800004 ER PT J AU Padin, S Shepherd, MC Cartwright, JK Keeney, RG Mason, BS Pearson, TJ Readhead, ACS Schaal, WA Sievers, J Udomprasert, PS Yamasaki, JK Holzapfel, WL Carlstrom, JE Joy, M Myers, ST Otarola, A AF Padin, S Shepherd, MC Cartwright, JK Keeney, RG Mason, BS Pearson, TJ Readhead, ACS Schaal, WA Sievers, J Udomprasert, PS Yamasaki, JK Holzapfel, WL Carlstrom, JE Joy, M Myers, ST Otarola, A TI The Cosmic Background Imager SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID SKY SURVEY; MICROWAVE; ANISOTROPIES; PERFORMANCE; ALTITUDE; EMISSION; DESIGN; SCALES; ARRAY; LIMIT AB Design and performance details are given for the Cosmic Background Imager (CBI), an interferometer array that is measuring the power spectrum of fluctuations in the cosmic microwave background radiation (CMBR) for multipoles in the range 400 50% EC by volume) displayed superior resilience to high temperature storage, in contrast to cells containing low EC-content electrolytes (< 25% EC by volume) which displayed much larger irreversible capacity losses and poorer lithium intercalation/de-intercalation kinetics after exposure to high temperatures. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7132-1 PY 2002 BP 53 EP 58 DI 10.1109/BCAA.2002.986368 PG 6 WC Electrochemistry; Engineering, Electrical & Electronic SC Electrochemistry; Engineering GA BU02J UT WOS:000174743400010 ER PT B AU Ratnakumar, BSV Smart, MC Surampudi, S AF Ratnakumar, BSV Smart, MC Surampudi, S BE Das, RSL Frank, H TI Electrochemical impedance spectroscopy and its applications to lithium ion cells SO SEVENTEENTH ANNUAL BATTERY CONFERENCE ON APPLICATIONS AND ADVANCES, PROCEEDINGS LA English DT Proceedings Paper CT 17th Annual Battery Conference on Applications and Advances CY JAN 15-18, 2002 CL CALIF STATE UNIV LONG BEACH, LONG BEACH, CA SP IEEE HO CALIF STATE UNIV LONG BEACH ID BATTERIES; ELECTROLYTES; ELECTRODES AB Electrochemical impedance spectroscopy (EIS) is a non-destructive technique often used to understand the interfacial behavior in electrochemical systems. The ability of the technique to segregate various processes, i.e., ohmic conduction, charge transfer, interfacial charging, mass transfer etc, makes it an elegant technique for electrochemical systems. Its applicability to lithium ion cells is further enhanced by the fact that surface films cover both the electrodes and especially the carbon anode. This paper describes the EIS response of individual electrodes in the lithium ion cells under a variety of experimental conditions, i.e., temperature, high temperature storage and cycling. C1 CALTECH, Jet Prop Lab, Electrochem Technol Grp, Pasadena, CA 91125 USA. RP Ratnakumar, BSV (reprint author), CALTECH, Jet Prop Lab, Electrochem Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 9 TC 3 Z9 3 U1 1 U2 10 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7132-1 PY 2002 BP 273 EP 277 DI 10.1109/BCAA.2002.986414 PG 5 WC Electrochemistry; Engineering, Electrical & Electronic SC Electrochemistry; Engineering GA BU02J UT WOS:000174743400056 ER PT J AU Abgrall, R Barth, T AF Abgrall, R Barth, T TI Residual distribution schemes for conservation laws via adaptive quadrature SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE residual distribution; fluctuation splitting; symmetric hyperbolic; entropy symmetrization ID COMPUTATIONAL FLUID-DYNAMICS; FINITE-ELEMENT FORMULATION; NAVIER-STOKES EQUATIONS; SYSTEMS AB This paper considers a family of nonconservative numerical discretizations for conservation laws which retain the correct weak solution behavior in the limit of mesh refinement whenever sufficient-order numerical quadrature is used. Our analysis of 2-D discretizations in nonconservative form follows the 1-D analysis of Hou and Le Floch [Math. Comp., 62 (1994), pp. 497-530]. For a specific family of nonconservative discretizations, it is shown under mild assumptions that the error arising from nonconservation is strictly smaller than the discretization error in the scheme. In the limit of mesh refinement under the same assumptions, solutions are shown to satisfy a global entropy inequality. Using results from this analysis, a variant of the "N" (Narrow) residual distribution scheme of van der Weide and Deconinck [Computational Fluid Dynamics '96, Wiley, New York, 1996, pp. 747-753] is developed for first-order systems of conservation laws. The modified form of the N-scheme supplants the usual exact single-state mean-value linearization of flux divergence, typically used for the Euler equations of gasdynamics, by an equivalent integral form on simplex interiors. This integral form is then numerically approximated using an adaptive quadrature procedure. This quadrature renders the scheme nonconservative in the sense described earlier so that correct weak solutions are still obtained in the limit of mesh refinement. Consequently, we then show that the modified form of the N-scheme can be easily applied to general (nonsimplicial) element shapes and general systems of first-order conservation laws equipped with an entropy inequality, where exact mean-value linearization of the flux divergence is not readily obtained, e. g., magnetohydrodynamics, the Euler equations with certain forms of chemistry, etc. Numerical examples of subsonic, transonic, and supersonic flows containing discontinuities together with multilevel mesh refinement are provided to verify the analysis. C1 Univ Bordeaux 1, F-33405 Talence, France. Inst Univ France, Paris, France. NASA, Ames Res Ctr, Informat Sci Directorate, Moffett Field, CA 94035 USA. RP Univ Bordeaux 1, 351 Cours Liberat, F-33405 Talence, France. EM abgrall@math.u-bordeaux.fr; barth@nas.nasa.gov RI Abgrall, Remi/J-3030-2012 NR 32 TC 19 Z9 19 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 EI 1095-7197 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PY 2002 VL 24 IS 3 BP 732 EP 769 PG 38 WC Mathematics, Applied SC Mathematics GA 642AB UT WOS:000180778300002 ER PT J AU Hagstrom, T Goodrich, J AF Hagstrom, T Goodrich, J TI Accurate radiation boundary conditions for the linearized euler equations in cartesian domains SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE radiation boundary conditions; Euler equations; aeroacoustics AB We construct, analyze, and test convergent sequences of radiation boundary conditions at planar boundaries for the compressible Euler equations linearized about a uniform, subsonic flow. First we formulate well-posed exact conditions, identifying one which involves only a single nonlocal term at each boundary. Next we develop the basic convergence theory for rational approximations to the symbol of the nonlocal term, which we then specialize to the Pade approximants. Finally, we present numerical experiments using a seventh order implementation of the approximate conditions. The experiments involve the long time propagation of initial pressure pulses in periodic and duct geometry. With these we conclude that i. standard low order conditions lead to O(1) errors over moderate times; ii. good accuracy can be obtained with sufficiently high order approximate conditions of Pade type; iii. the actual errors are consistent with the theory spectral convergence with increasing order for fixed times but a need to use high order approximations for long time accuracy. C1 Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. NASA, Glenn Res Ctr, Acoust Branch, Cleveland, OH 44135 USA. RP Hagstrom, T (reprint author), Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. EM hagstrom@math.unm.edu; John.Goodrich@grc.nasa.gov NR 24 TC 12 Z9 12 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD JAN 23 PY 2002 VL 24 IS 3 BP 770 EP 795 PG 26 WC Mathematics, Applied SC Mathematics GA 642AB UT WOS:000180778300003 ER PT S AU Neudeck, PG Powell, JA Trunek, A Spry, D Beheim, GM Benavage, E Abel, P Vetter, WM Dudley, M AF Neudeck, PG Powell, JA Trunek, A Spry, D Beheim, GM Benavage, E Abel, P Vetter, WM Dudley, M BE Yoshida, S Nishino, S Harima, H Kimoto, T TI Homoepitaxial 'web growth' of SiC to terminate C-axis screw dislocations and-enlarge step-free surfaces SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE AFM; cantilever; CVD; homoepitaxial growth; step-free surfaces; SWBXT; web growth AB Homoepitaxial CVD growth of thin lateral cantilevers emanating from the edges of mesa patterns dry-etched into on-axis commercial 4H-SiC substrates prior to growth is reported. Cantilevers on the order of a micrometer thick extending tens of micrometers from the edge of a mesa have been grown. The termination of vertically propagating screw dislocations, including a micropipe, that are overgrown by the cantilevers has been demonstrated, in large part because the crystal structure of the cantilevers is established laterally from the mesa sidewalls. This technique could help reduce performance-degrading dislocations in SiC electrical devices. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, Cleveland, OH 44135 USA. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Neudeck, PG (reprint author), NASA, Glenn Res Ctr, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 TC 5 Z9 5 U1 0 U2 1 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 251 EP 254 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100059 ER PT S AU Neudeck, PG Powell, JA Trunek, AJ Huang, XRR Dudley, M AF Neudeck, PG Powell, JA Trunek, AJ Huang, XRR Dudley, M BE Yoshida, S Nishino, S Harima, H Kimoto, T TI Growth of defect-free 3C-SiC on 4H-and 6H-SiC mesas using step-free surface heteroepitaxy SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE 3C-SiC; cubic polytype; heteroepitaxy; lattice mismatch; nucleation; pseudomorphic; stacking faults AB A new growth process, herein named step-free surface heteroepitaxy, has achieved 3C-SiC films completely free of double positioning boundaries and stacking faults on 4H-SiC and 6H-SiC substrate mesas. The process is based upon the initial 2-dimensional nucleation and lateral expansion of a single island of 3C-SiC on a 4H- or 6H-SiC mesa surface that is completely free of bilayer surface steps. Our experimental results indicate that substrate-epilayer in-plane lattice mismatch (Deltaa/a = 0.0854% for 3C/4H) is at least partially relieved parallel to the interface in the initial bilayers of the heterofilm, producing an at least partially relaxed 3C-SiC film without dislocations that undesirably thread through the thickness of the epilayer. This result should enable realization of improved 3C-SiC devices. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, Cleveland, OH 44135 USA. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Neudeck, PG (reprint author), NASA, Glenn Res Ctr, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 13 TC 23 Z9 23 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 311 EP 314 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100074 ER PT S AU Dudley, M Vetter, WM Huang, XR Neudeck, PG Powell, JA AF Dudley, M Vetter, WM Huang, XR Neudeck, PG Powell, JA BE Yoshida, S Nishino, S Harima, H Kimoto, T TI Polytype identification and mapping in heteroepitaxial growth of 3C on atomically flat 4H-SiC mesas using synchrotron white-beam X-ray topography SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE 3C SiC; atomically flat mesas; heteroepitaxial growth; mismatch strain; polytype mapping; screw dislocations; synchrotron white-beam X-ray topography (SWBXT) ID CARBIDE AB This paper reports the application of synchrotron white beam X-ray topography to the identification and mapping of the polytype distribution in nominally 3C heteroepitaxial films grown on 4H-SiC mesas which, prior to epilayer growth, were subjected to the recently reported procedure for producing atomic flatness [I]. Results from studies carried out on two wafers are presented. The first (wafer 1), a non-optimal region of one of the 4H-SiC wafers that was described in [1], was subjected to the procedure for production of atomic flatness. The region of interest, experienced imperfect control of the local supersaturation and significant 2D terrace nucleation of the two variants of 3C polytype was inadvertently produced. This sample served to demonstrate the capability for polytype mapping. The second (wafer 2) consisted of a 4H wafer where more controlled heteroepitaxy was carried out following the successful production of the atomically flat mesas. This sample served to demonstrate proof of concept, i.e. to confirm that dislocation-free mesas could be made atomically flat and that complete DPB-free coverage of these atomically flat mesas by one or other of the 3C polytype variants could be achieved. For both crystals, back reflection topographs revealed strain contrast bounding regions that had experienced 3C growth. The apparent mismatch between substrate and epilayer was further investigated using High Resolution Triple-Axis X-ray Diffraction (HRTXD). Preliminary Deltaa/a and Deltac/c values obtained for the epilayers are presented. C1 SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dudley, M (reprint author), SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 391 EP 394 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100093 ER PT S AU Okojie, RS Xhang, M Pirouz, P Tumakha, S Jessen, G Brillson, LJ AF Okojie, RS Xhang, M Pirouz, P Tumakha, S Jessen, G Brillson, LJ BE Yoshida, S Nishino, S Harima, H Kimoto, T TI 4H-to 3C-SiC polytypic transformation during oxidation SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE CLS; I-V characteristics; LEEN; oxidation; polytypic transformation; quantum wells; TEM; XPS ID SILICON-CARBIDE; VANADIUM AB The formation of single and multiple stacking faults that sometimes give rise to 3C-SiC was observed in a highly doped n-type 4H-SiC epilayer following thermal oxidation. Transmission electron microscopy following oxidation revealed single stacking faults and bands of 3C-SiC within a 4H-SiC matrix in the epilayer. In addition to the 3.22 eV photon energy peak corresponding to 4H-SiC, depth-resolved cathodoluminescence spectroscopy at 25 degreesC based on low energy-excited electron nanoscale luminescence revealed a spectral peak at 2.5 eV photon energy that was not present in the sample prior to oxidation. The polytypic transformation is tentatively attributed to the motion of Shockley partial dislocations on parallel (0001) slip planes. The generation and motion of these partials may have been induced by the stresses that were generated during oxidation, and/or the epilayer stresses generated by change in lattice constant due to its heavy doping. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. RP Okojie, RS (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 8 TC 29 Z9 29 U1 0 U2 2 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 451 EP 454 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100108 ER PT S AU Shigiltchoff, O Kimoto, T Hobgood, D Neudeck, PG Porter, LM Devaty, RP Choyke, WJ AF Shigiltchoff, O Kimoto, T Hobgood, D Neudeck, PG Porter, LM Devaty, RP Choyke, WJ BE Yoshida, S Nishino, S Harima, H Kimoto, T TI Schottky barriers for Pt on 6H-and 4H-SiC (0001), (000(1)over-bar), (1(1)over-bar00) and (1(2)over-bar10) faces measured by I-V, C-V and internal photoemission SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE breakdown; C-V measurements; I-V; internal photoemission; Schottky barrier ID CONTACTS AB Measurements of the Schottky barrier heights (SBH) of 4H and 6H SiC/Pt contacts reveal a dependence on the crystallographic face of the SiC epilayer. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Kyoto Univ, Dept Elect Sci & Engn, Kyoto 6068501, Japan. Cree Res Inc, Durham, NC 27703 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. RP Shigiltchoff, O (reprint author), Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NR 8 TC 3 Z9 3 U1 1 U2 1 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 921 EP 924 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100222 ER PT S AU Okojie, RS Lukco, D Keys, L Tumakha, S Brillson, LJ AF Okojie, RS Lukco, D Keys, L Tumakha, S Brillson, LJ BE Yoshida, S Nishino, S Harima, H Kimoto, T TI Surface morphology and chemistry of 4H-and 6H-SiC after cyclic oxidation SO SILICON CARBIDE AND RELATED MATERIALS 2001, PTS 1 AND 2, PROCEEDINGS SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Silicon Carbide and Related Materials CY OCT 28-NOV 02, 2001 CL TSUKUBA, JAPAN SP Sci& Technol Promot Fdn Ibaraki, Commwmorat Assoc Japan World Exposit, Fdn Promot Mat Sci & Technol Japan, Kansai Res Fdn Technol Promot, Murate Sci Fdn, Ogasawara Fdn Promot Sci & Engn, Res Fdn Electrotechnol Chubu, Support Ctr Adv Telecommunicat Technol Res, Telecommunicat Adv Fdn, ARO-Fe, AOARD, ONRIFO, Cree Inc, DENSO Corp, Emcore Corp, Epigress AB, Fuji Elect Corp Res & Dev Ltd, Furukawa Elect Co Ltd, Hitachi Ltd, Kansai Elect Power Co Inc, Matsushita Elect Ind Co Inc, Mitsubishi Elect Corp, Mitsubishi Mat Corp, New Japan Radio Co Ltd, New Met & Chem Corp Ltd, Nichia Corp, Nippon Steel Corp, Nissan Motor Co Ltd, Nisso Shoji Co Ltd, Oki Elect Ind Co Ltd, ROHM Co Ltd, Sanyo Elect Co Ltd, Sharp Corp, Shindengen Elect Mfg Co Ltd, Shin-Etsu Hansotai Co Ltd, Showa Denko K K, Sony Corp, Sterling Semiconductor Inc, Sumitomo Corp, Sumitomo Elect Ind Ltd, Sumitomo Osaka Cement Co Ltd, Toshiba Corp, Toyoda Gosei Co Ltd, Toyoda Cent R&D Labs Inc, Toyo Tanso Co Ltd, ULVAC Inc, Universal Syst Co Ltd DE AFM; CLS; LEEN; oxidation; surface chemistry; surface morphology; XPS ID SCHOTTKY-BARRIER HEIGHT; CONTACTS AB The analysis of the surface and sub-surface of n-type 6H- and 4H-SiC was performed after cyclic oxidation and oxide removal using X-ray photoelectron spectroscopy and multiple scans with atomic force microscope. The results reveal that the disappearance of C Is binding energy spectral shoulders that arise from adventitious carbon and related compounds is tracked by the progression toward smoother surface morphology after more cycles of oxidation and oxide stripping. However, the 4H-SiC progression toward further smoothening was interrupted by sudden increase in roughness after the second cycle of oxidation and stripping, with a corresponding re-introduction of adventitious carbon. Low energy electron nanoluminescence spectra reveal prominent electronic states at 1.9 and 3.3 eV at the 6H/metal and 2.0 eV at the 4H/metal interface that are independent of the process steps. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. AYT Res, Brookpark, OH 44142 USA. Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. RP Okojie, RS (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 10 TC 4 Z9 4 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-894-X J9 MATER SCI FORUM PY 2002 VL 389-3 BP 1101 EP 1104 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BU89T UT WOS:000177321100266 ER PT S AU Neudeck, PG Powell, JA Spry, DJ Trunek, AJ Huang, XR Vetter, WM Dudley, M Skowronski, M Liu, JQ AF Neudeck, PG Powell, JA Spry, DJ Trunek, AJ Huang, XR Vetter, WM Dudley, M Skowronski, M Liu, JQ BE Bergman, P Janzen, E TI Characterization of 3C-SiC films grown on 4H-and 6H-SiC substrate mesas during step-free surface hetero-epitaxy SO SILICON CARBIDE AND RELATED MATERIALS - 2002 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th Euopean Conference on Silicon Carbide and Related Materials (ECSCRM 2002) CY SEP 02-25, 2002 CL LINKOPING, SWEDEN SP European Commiss, High Level Sci Conf, Swedish Res Council, Swedish Agcy Innovat Syst, Swedish Fdn Strateg Res, City Linkoping, Linkopings Univ, Embassy Italy Sweden, US Off Naval Res Int Field Off, ABB, CREE, Epigress, SiCrystal, Okmetic DE 3C-SiC; cubic-SiC; epitaxial growth; hetero-epitaxy; step-free surface hetero-epitaxy ID X-RAY TOPOGRAPHY; POLYTYPE IDENTIFICATION AB This paper reports detailed structural characterization of 3C-SiC heteroepitaxial films grown on 4H- and 6H-SiC mesa surfaces. 3C-SiC heterofilms grown by the "step-free surface heteroepitaxy" process, free of double-positioning boundary (DPB) and stacking-fault (SF) defects, were compared to less-optimized 3C-SiC heterofilms using High Resolution X-ray Diffraction (HRXRD), High Resolution Cross-sectional Transmission Electron Microscopy (HRXTEM), molten potassium hydroxide (KOH) etching, and dry thermal oxidation. The results suggest that step free surface heteroepitaxy enables remarkably benign partial lattice mismatch strain relief during heterofilm growth. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, Cleveland, OH 44135 USA. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. Carnegie Mellon Univ, Dept Mat Sci, Pittsburgh, PA 15213 USA. RP Neudeck, PG (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 77-1, Cleveland, OH 44135 USA. RI Skowronski, Marek/A-8934-2011 OI Skowronski, Marek/0000-0002-2087-0068 NR 14 TC 2 Z9 2 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 J9 MATER SCI FORUM PY 2002 VL 433-4 BP 213 EP 216 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BX37E UT WOS:000185077700050 ER PT S AU Dudley, M Huang, XR Vetter, WM Neudeck, PG AF Dudley, M Huang, XR Vetter, WM Neudeck, PG BE Bergman, P Janzen, E TI Synchrotron White Beam X-ray Topography and High Resolution Triple Axis X-ray Diffraction studies of defects in SiC substrates, epilayers and devices SO SILICON CARBIDE AND RELATED MATERIALS - 2002 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th Euopean Conference on Silicon Carbide and Related Materials (ECSCRM 2002) CY SEP 02-25, 2002 CL LINKOPING, SWEDEN SP European Commiss, High Level Sci Conf, Swedish Res Council, Swedish Agcy Innovat Syst, Swedish Fdn Strateg Res, City Linkoping, Linkopings Univ, Embassy Italy Sweden, US Off Naval Res Int Field Off, ABB, CREE, Epigress, SiCrystal, Okmetic DE defect; micropipe; mismatch; screw dislocation; synchrotron topography; triple-axis diffraction ID 6H-SIC SINGLE-CRYSTALS; POLYTYPE IDENTIFICATION; SCREW DISLOCATIONS; MESAS; GROWTH; BREAKDOWN AB A short review is presented of recent Synchrotron White Beam X-ray Topography (SWBXT) and High Resolution Triple-Axis X-ray Diffraction (HRTXD) studies of defects and distortions in 4H and 6H SiC substrates, homo- and hetero-epitaxial layers grown on these substrates, and devices fabricated in these layers. In the substrates, defects observed include closed-core and hollow-core screw dislocations (micropipes) in 6H and 4H, deformation induced basal plane dislocations in 6H and 4H, and small angle boundaries in 4H. For the hetero-epitaxial layers, consisting of 3C grown on specially prepared 4H and 6H mesas, detailed correlation between the defect content of the mesas and the choice of 3C variant and the subsequent lattice mismatch between heteroepilayer and substrate is presented. A brief review of the application of SWBXT to the understanding of the generation of defects during device performance will be presented. C1 SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dudley, M (reprint author), SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. NR 21 TC 0 Z9 0 U1 0 U2 1 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 J9 MATER SCI FORUM PY 2002 VL 433-4 BP 247 EP 252 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BX37E UT WOS:000185077700058 ER PT S AU Shigiltchoff, O Bai, S Devaty, RP Choyke, WJ Kimoto, T Hobgood, D Neudeck, PG Porter, LM AF Shigiltchoff, O Bai, S Devaty, RP Choyke, WJ Kimoto, T Hobgood, D Neudeck, PG Porter, LM BE Bergman, P Janzen, E TI Schottky barriers for Pt, Mo and Ti on 6H and 4H SiC (0001), (000(1)over-bar), (1(1)over-bar-00) and (1(2)over-bar-10) faces measured by I-V, C-V and internal photoemission SO SILICON CARBIDE AND RELATED MATERIALS - 2002 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 4th Euopean Conference on Silicon Carbide and Related Materials (ECSCRM 2002) CY SEP 02-25, 2002 CL LINKOPING, SWEDEN SP European Commiss, High Level Sci Conf, Swedish Res Council, Swedish Agcy Innovat Syst, Swedish Fdn Strateg Res, City Linkoping, Linkopings Univ, Embassy Italy Sweden, US Off Naval Res Int Field Off, ABB, CREE, Epigress, SiCrystal, Okmetic DE breakdown; current-voltage; internal photoemission; Schottky barrier ID DIODES AB The Schottky barrier height of 4H and 6H SiC/Metal (Pt, Mo, Ti) contacts depends on the crystallographic face of the SiC epilayer. The breakdown fields of Schottky contacts without edge terminations are also discussed. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Kyoto Univ, Dept Elect Sci & Engn, Kyoto 60601, Japan. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cree Inc, Durham, NC 27703 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. RP Shigiltchoff, O (reprint author), Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NR 9 TC 1 Z9 1 U1 2 U2 2 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 J9 MATER SCI FORUM PY 2002 VL 433-4 BP 705 EP 708 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BX37E UT WOS:000185077700170 ER PT B AU Oyafuso, F Klimeck, G Bowen, RC Boykin, TB AF Oyafuso, F Klimeck, G Bowen, RC Boykin, TB GP JAPAN SOCIETY OF APPLIED PHYSICS JAPAN SOCIETY OF APPLIED PHYSICS TI Nanoelectronic 3-D (NEMO 3-D) simulation of multimillion atom quantum dot systems SO SISPAD 2002: INTERNATIONAL CONFERENCE ON SIMULATION OF SEMICONDUCTOR PROCESSES AND DEVICES LA English DT Proceedings Paper CT International Conference on Simulation of Semiconductor Processes and Devices (SISPAD 2002) CY SEP 04-06, 2002 CL KOBE, JAPAN SP Japan Soc Appl Phys, IEEE Electron Devices Soc, Inst Electr, Informat & Comun Engineers, IEEE EDS Japan Chapter, IEEE EDS Kansai Chapter AB The convergence of electron and hole ground states of a dome-shaped In0.6Ga0.4As quantum dot as a function of the size of the surrounding buffer is explored within an sp(3)d(5)s(*) tight binding model. It is found that although the quantum dot encompasses only 2 x 10(5) atoms, proper convergence of ground state eigenergies requires that over 10 times as many atoms need to be included in the simulation domain. It is also found that the disorder-induced broadening is very sensitive to the applied boundary conditions. Examination of local eigenenergies as functions of position shows similar convergence problems and indicates that an inaccurate resolution of the equilibrium atomic positions due to truncation of the simulation domain may be the source of the slow ground state convergence. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Oyafuso, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 7 TC 0 Z9 0 U1 0 U2 1 PU BUSINESS CENTER ACADEMIC SOC JAPAN PI TOKYO PA 5-16-9, HONKOMAGOME, 5-CHOME, BUNKYO-KU, TOKYO, 113-8622, JAPAN BN 4-89114-027-5 PY 2002 BP 163 EP 166 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Engineering; Instruments & Instrumentation; Physics GA BW06Z UT WOS:000180780700040 ER PT B AU Kao, D Luo, A Dungan, JL Pang, A AF Kao, D Luo, A Dungan, JL Pang, A BE Williams, AD TI Visualizing spatially varying distribution data SO SIXTH INTERNATIONAL CONFERENCE ON INFORMATION VISUALISATION, PROCEEDINGS LA English DT Proceedings Paper CT 6th International Conference on Information Visualisation CY JUL 10-12, 2002 CL LONDON, ENGLAND DE parametric statistics; shape description; uncertainty representation; probability density function ID UNCERTAINTY AB Box plot is a compact representation that encodes the minimum, maximum, mean, median, and quartile information of a distribution. In practice, a single box plot is drawn for each variable of interest. With the advent of more accessible computing power, we are now facing the problem of visualizing data where there is a distribution at each 2D spatial location. Simply extending the box plot technique to distributions over 2D domain is not straightforward. One challenge is reducing the visual clutter if a box plot is drawn over each grid location in the 2D domain. This paper presents and discusses two general approaches, using parametric statistics and shape descriptors, to present 2D distribution data sets. Both approaches provide additional insights compared to the traditional box plot technique. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Dungan, Jennifer/G-9921-2016 OI Dungan, Jennifer/0000-0002-4863-1616 NR 9 TC 17 Z9 17 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 0-7695-1656-4 PY 2002 BP 219 EP 225 DI 10.1109/IV.2002.1028780 PG 7 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Computer Science, Software Engineering SC Computer Science GA BU89V UT WOS:000177323000032 ER PT B AU Ganoe, GG Johnson, TA AF Ganoe, GG Johnson, TA GP AMS AMS TI Evaluation of experimental data from the gains balloon GPS surface reflection instrument SO SIXTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 6th Symposium on Integrated Observing Systems CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc AB The GPS Surface Reflection Instrument was integrated as an experiment on the GAINS (Global Air-ocean IN-situ System) 48-hour balloon mission flown in September 2001. The data collected by similar instruments in the past has been used to measure sea state from which ocean surface winds can be accurately estimated. The GPS signal has also been shown to be reflected from wetland areas and even from subsurface moisture. The current version of the instrument has been redesigned to be more compact, use less power, and withstand a greater variation in environmental conditions than previous versions. This instrument has also incorporated a new data collection mode to track 5 direct satellites (providing a continuous navigation solution) and multiplex the remaining 7 channels to track the reflected signal of the satellite tracked in channel 0. The new software mode has been shown to increase the signal to noise ratio of the collected data and enhance the science return of the instrument. During the 48-hour flight over the Northwest US, the instrument will measure surface reflections that can be detected over the balloon's ground track. Since ground surface elevations in this area vary widely from the WGS-84 ellipsoid altitude, the instrument software has been modified to incorporate a surface altitude correction based on USGS 30-minute Digital Elevation Models. Information presented will include facts about instrument design goals, data collection methodologies and algorithms, and results of the science data analyses for the 48-hour mission. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ganoe, GG (reprint author), NASA, Langley Res Ctr, MS 328, Hampton, VA 23681 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 2002 BP 1 EP 5 PG 5 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BV53W UT WOS:000179289900001 ER PT B AU Demoz, B Miller, D Schwemmer, G AF Demoz, B Miller, D Schwemmer, G GP AMS AMS TI Application of harlie measurements in mesoscale studies: measurements of aerosol backscatter and winds SO SIXTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 6th Symposium on Integrated Observing Systems CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Demoz, B (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 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 2002 BP 68 EP 70 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BV53W UT WOS:000179289900017 ER PT B AU Masutani, M Woollen, JC Lord, SJ Terry, J Kleespies, TJ Derber, JC Atlas, R AF Masutani, M Woollen, JC Lord, SJ Terry, J Kleespies, TJ Derber, JC Atlas, R GP AMS AMS TI Calibration and error sensitivity tests for NPOESS/OSSE SO SIXTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 6th Symposium on Integrated Observing Systems CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID ANALYSIS SYSTEM C1 NOAA, NWS, NCEP, EMC, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, NESDIS, Camp Springs, MD USA. RP Masutani, M (reprint author), NOAA, NWS, NCEP, EMC, 5200 Auth Rd, Camp Springs, MD 20746 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 71 EP 76 PG 6 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BV53W UT WOS:000179289900018 ER PT B AU Hu, H Liu, WT Stiles, BW AF Hu, H Liu, WT Stiles, BW GP AMS AMS TI Catalina Eddy captured by NASA QuikSCAT satellite SO SIXTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 6th Symposium on Integrated Observing Systems CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID KELVIN WAVES; SIMULATION; PREDICTION C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hu, H (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 120 EP 124 PG 5 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BV53W UT WOS:000179289900029 ER PT B AU Demoz, B Evans, K Digirolamo, P Whiteman, D Aligo, E AF Demoz, B Evans, K Digirolamo, P Whiteman, D Aligo, E GP AMS AMS TI Raman lidar measurement of water vapor mixing ratio and aerosols during a bore-front case. SO SIXTH SYMPOSIUM ON INTEGRATED OBSERVING SYSTEMS LA English DT Proceedings Paper CT 6th Symposium on Integrated Observing Systems CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Demoz, B (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 210 EP 212 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing SC Meteorology & Atmospheric Sciences; Remote Sensing GA BV53W UT WOS:000179289900048 ER PT S AU Bar-Cohen, Y AF Bar-Cohen, Y BE Kundu, T TI Biologically inspired robots as artificial inspectors SO SMART NONDESTRUCTIVE EVALUATION FOR HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Smart Nondestructive Evaluation for Health Monitoring of Structural and Biological Systems CY MAR 18-20, 2002 CL NEWPORT BEACH, CA SP SPIE DE NDE; EAP; artificial muscles; robotics; biomimetics; biologically inspired robots; automation AB Imagine an inspector conducting an NDE on an aircraft where you notice something is different about him - he is not real but rather he is a robot. Your first reaction would probably be to say "it's unbelievable but he looks real" just as you would react to an artificial flower that is a good imitation. This science fiction scenario could become a reality at the trend in the development of biologically inspired technologies, and terms like artificial intelligence, artificial muscles, artificial vision and numerous others are increasingly becoming common engineering tools. For many years, the trend has been to automate processes in order to increase the efficiency of performing redundant tasks where various systems have been developed to deal with specific production line requirements. Realizing that some parts are too complex or delicate to handle in small quantities with a simple automatic system, robotic mechanisms were developed. Aircraft inspection has benefited from this evolving technology where manipulators and crawlers are developed for rapid and reliable inspection. Advancement in robotics towards making them autonomous and possibly look like human, can potentially address the need to inspect structures that are beyond the capability of today's technology with configuration that are not predetermined. The operation of these robots may take place at harsh or hazardous environments that are too dangerous for human presence. Making such robots is becoming increasingly feasible and in this paper the state of the art will be reviewed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 82-105, Pasadena, CA 91109 USA. NR 12 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 0-8194-4450-2 J9 P SOC PHOTO-OPT INS PY 2002 VL 4702 BP 41 EP 48 DI 10.1117/12.469902 PG 8 WC Engineering, Biomedical; Instruments & Instrumentation; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BU90E UT WOS:000177343800005 ER PT S AU Anastasi, RF Madaras, EI AF Anastasi, RF Madaras, EI BE Kundu, T TI Investigating the use of ultrasonic guided waves for aging wire insulation assessment SO SMART NONDESTRUCTIVE EVALUATION FOR HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Smart Nondestructive Evaluation for Health Monitoring of Structural and Biological Systems CY MAR 18-20, 2002 CL NEWPORT BEACH, CA SP SPIE DE guided waves; wire insulation; cylindrical wave-guide; ultrasonic ID RODS AB Aging wiring has become a critical issue to DoD, NASA, FAA, and Industry. The problem is that insulation on environmentally aged wire becomes brittle and cracks. This exposes the underlying conductive wire to the potential for short circuits and fire. The difficulty is that techniques to monitor aging wire problems focus on applying electrical sensing techniques that are not very sensitive to the wire insulation. Thus, the development of methods to quantify and monitor aging wire insulation is highly warranted. Measurement of wire insulation stiffness by ultrasonic guided waves is being examined. Initial laboratory tests were performed on a simple model consisting of a solid cylinder and then a solid cylinder with a polymer coating. Experimental measurements showed that the lowest order axisymmetric mode may be sensitive to stiffness changes in the wire insulation. To test this theory, mil-spec wire samples MIL-W-81381, MIL-W-22759/34, and MIL-W-22759/87 (typically found in aircraft) were heat-damaged in an oven, in a range of heating conditions. The samples were 12, 16, and 20 gauge and the heat-damage introduced material changes in the wire-insulation that made the originally flexible insulation brittle and darker in color. Axisymmetric mode phase-velocity increased for the samples that were exposed to heat for longer duration. For example, the phase velocity in the 20-gauge MIL-W-22759/34 wire changed from a baseline value of 2790m/s to 3280m/s and 3530m/s for one-hour exposures to 349degreesC and 399degreesC, respectively. Although the heat-damage conditions are not the same as environmental aging, we believe that with further development and refinements, the ultrasonic guided waves can be used to inspect wire-insulation for detrimental environmental aging conditions. C1 NASA, Langley Res Ctr, USA, Army Res Lab,Vehicle Technol Directorate,AMSRL VT, Hampton, VA 23681 USA. RP NASA, Langley Res Ctr, USA, Army Res Lab,Vehicle Technol Directorate,AMSRL VT, Hampton, VA 23681 USA. NR 7 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 0-8194-4450-2 J9 PROC SPIE PY 2002 VL 4702 BP 76 EP 82 DI 10.1117/12.469912 PG 7 WC Engineering, Biomedical; Instruments & Instrumentation; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BU90E UT WOS:000177343800008 ER PT S AU Koshti, AM AF Koshti, AM BE Kundu, T TI Estimating temperature rise in pulsed thermography using irreversible temperature indicators SO SMART NONDESTRUCTIVE EVALUATION FOR HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Smart Nondestructive Evaluation for Health Monitoring of Structural and Biological Systems CY MAR 18-20, 2002 CL NEWPORT BEACH, CA SP SPIE DE temperature; flash lamps; thermography; nondestructive evaluation AB One of the nondestructive thermography inspection techniques uses photographic flash lamps. The flash lamps provide a short duration (about 0.005 sec) heat pulse. The short burst of energy results in a momentary rise in the surface temperature of part. The temperature rise may be detrimental to the top layer of part. Therefore, it is necessary to ensure the nondestructive nature of the technique. Heat damage is dependent upon the magnitude of temperature rise. A direct method for the temperature measurement uses an infrared pyrometer or camera with a response time shorter than the flash duration. In this paper, an alternative technique is given using the irreversible temperature indicators. This is an indirect technique and it measures the temperature rise on the irreversible temperature indicators and computes the incident flux. Once the flux is known, the temperature rise on part can be computed. A wedge shaped irreversible temperature indicator for measuring the flux is proposed. A procedure is given to use the wedge indicator. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Koshti, AM (reprint author), NASA, Kennedy Space Ctr, FL 32899 USA. NR 3 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 0-8194-4450-2 J9 P SOC PHOTO-OPT INS PY 2002 VL 4702 BP 191 EP 201 DI 10.1117/12.469878 PG 11 WC Engineering, Biomedical; Instruments & Instrumentation; Materials Science, Characterization & Testing; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BU90E UT WOS:000177343800019 ER PT S AU Bryant, RG Effinger, RT Aranda, I Copeland, BM Covington, EW AF Bryant, RG Effinger, RT Aranda, I Copeland, BM Covington, EW BE Lynch, CS TI Active piezoelectric diaphragms SO SMART STRUCTURES AND MATERIALS 2002: ACTIVE MATERIALS: BEHAVIOR AND MECHANICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE piezoelectric actuators; piezoelectric diaphragms; active materials; Radial Field Diaphragms; NASA RFDs AB Several active piezoelectric diaphragms were fabricated by placing unelectroded piezoelectric disks between copper clad films patterned with Inter-Circulating Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is radially distributed electric field that mechanically strains the piezo-ceramic along the Z-axis (perpendicular to the applied electric field), rather than the expected in-plane (XY-axis) direction. Unlike other out of plane piezoelectric actuators, which are benders, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements while maintaining a constant circumference. This paper covers the fabrication and characterization of these diaphragms as a function of poling field strength, ceramic diameter and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage ranging from DC to 10 Hz. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bryant, RG (reprint author), NASA, Langley Res Ctr, MS 226, Hampton, VA 23681 USA. NR 4 TC 8 Z9 8 U1 0 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 0-8194-4447-2 J9 P SOC PHOTO-OPT INS PY 2002 VL 4699 BP 303 EP 314 DI 10.1117/12.474988 PG 12 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites; Physics, Condensed Matter SC Materials Science; Physics GA BV06L UT WOS:000177732900032 ER PT S AU Lach, CL Turner, TL Taminger, KM Shenoy, RN AF Lach, CL Turner, TL Taminger, KM Shenoy, RN BE Lynch, CS TI Effects of thermomechanical history on the tensile behavior of Nitinol ribbon SO SMART STRUCTURES AND MATERIALS 2002: ACTIVE MATERIALS: BEHAVIOR AND MECHANICS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE shape memory alloys; Nitinol; NiTi; microstructure; stress-strain behavior; XRD; DSC ID SHAPE-MEMORY ALLOY; SMA HYBRID COMPOSITES; PHASE; TRANSFORMATION; STRESS AB Shape memory alloys (SMAs) have enormous potential for a wide variety of applications. A large body of work exists on the characterization of the microstructure and stress-strain behavior of these alloys, Nitinol (NiTi) in particular. However, many attributes of these materials are yet to be fully understood. Previous work at NASA Langley Research Center (LaRC) has included fabrication of hybrid composite specimens with embedded Nitinol actuators and modeling of their thermomechanical behavior. An intensive characterization effort has been undertaken to facilitate fundamental understanding of the stress-strain behavior of this alloy in relation to its microstructure and to promote implementation of Nitinol in aerospace applications. Previous work revealed attributes of the Nitinol ribbon that were not easily rationalized with existing data in the literature. In particular, tensile behavior at ambient temperature showed significant dependence on the thermomechanical history prior to testing. The present work is focused on characterizing differences in the microstructure of Nitinol ribbons exposed to four different thermomechanical histories and correlation of the microstructure with tensile properties. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) analysis were employed to rationalize the microstructures present after exposure to various thermomechanical histories. Three of the Nitinol ribbon conditions were reversible upon heating (in the DSC) through the reverse transformation temperature (A(f)) to transform the microstructure to austenite. However, the prior thermomechanical conditioning for the Nitinol ribbon that reflected the entire fabrication procedure (4% thermal cycle condition) was found to have an irreversible effect on the microstructure, as it remained unchanged after repeated complete thermal cycles. Tensile tests were conducted to determine the effect of prior thermomechancial conditioning on both the tensile behavior of the Nitinol ribbons and the stress state of the microstructure. The stress-strain behavior of the Nitinol actuators appears to be governed by the interplay between two major variables: namely, microstructural constituents such as the R-phase and the martensite; and the stress state of these constituents (whether twinned with low residual stresses, or detwinned with high residual stresses). The most significant difference in the stress-strain behavior of the four conditions, the critical stress required to achieve an initial stress plateau, was found to depend on both the amount and stress state (twinned or detwinned) of R-phase present in the initial microstructure. Thus, the effect of prior thermomechanical processing is critical to the resulting tensile behavior of the Nitinol actuator. For numerical modeling inputs one must take into account the entire fabrication process on the Nitinol actuator. C1 NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. RP Lach, CL (reprint author), NASA, Langley Res Ctr, Met & Thermal Struct Branch, Mail Stop 188A, Hampton, VA 23681 USA. NR 16 TC 3 Z9 3 U1 1 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 0-8194-4447-2 J9 P SOC PHOTO-OPT INS PY 2002 VL 4699 BP 323 EP 334 DI 10.1117/12.474990 PG 12 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites; Physics, Condensed Matter SC Materials Science; Physics GA BV06L UT WOS:000177732900034 ER PT S AU Bar-Cohen, Y AF Bar-Cohen, Y BE BarCohen, Y TI Electro-active polymers: current capabilities and challenges SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE EAP; robotics; biomimetics; biologically inspired robots AB In the last ten years, new EAP materials have emerged that exhibit large displacement in response to electrical stimulation enabling great potential for the field. To develop efficient and robust EAP material for practical applications efforts are underway to understand the behavior of EAP materials and improved characterization techniques. Further, to enhance the actuation force the basic principles are being studied using comprehensive material science, electro-mechanics analytical tools and improved material processing techniques to gain better understanding of the parameters that control the EAP electro-activation force and deformation. The processes of synthesizing, fabricating, electroding, shaping and handling are being refined to maximize the EAP materials actuation capability and robustness. Methods of reliably characterizing the response of these materials are required to establish database with documented material properties in order to support design engineers considering use of these materials and towards making EAP as actuators of choice. Various configurations of EAP actuators and sensors need to be studied and modeled to produce an arsenal of effective smart EAP driven system. The development of the infrastructure is a multidisciplinary task involving materials science, chemistry, electro-mechanics, computers, electronics, and others. This paper will be a review of the status of the EAP field and the challenges to practical application of EAP materials as actuators. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 82-105, Pasadena, CA 91109 USA. NR 12 TC 39 Z9 39 U1 1 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4443-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4695 BP 1 EP 7 DI 10.1117/12.475159 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700001 ER PT S AU Su, J Costen, RC Harrison, JS AF Su, J Costen, RC Harrison, JS BE BarCohen, Y TI Performance evaluation of bending actuators made from electrostrictive graft elastomers SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE electrostrictive; graft elastomer; bending actuator; output force; modeling ID POLYURETHANE ELASTOMER AB Recently a new class of electrostrictive polymers, called electrostrictive graft elastomers, was developed at NASA Langley Research Center. In this work, the output force of a bending actuator made from electrostrictive graft elastomer was measured and modeled to understand the dependence of performance on device configuration. This understanding should lead to better actuator design and fabrication. The prototype bending actuator is 47 gm thick and 8 mm wide. The output bending force at the tip was measured as a function of applied voltage and the distance from the tip to the holding stage. The output force at 2.1 kV increases from 124 muN at a length of 33.5 min to 662 muN at 7 mm. According to a small displacement, 5-layer, strength-of-materials model, the output bending force of the actuator varies inversely with its length and directly with the square of the applied voltage. Consequently, the output bending force can be about 5 mN when the length of the actuator is reduced to 1 mm for application to micro-electromechanical (MEMS) devices. The experimental results will be presented and a method for enhancing the performance will also be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Su, J (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 9 TC 1 Z9 1 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4443-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4695 BP 104 EP 110 DI 10.1117/12.475154 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700012 ER PT S AU Bao, XQ Bar-Cohen, Y Lih, SS AF Bao, XQ Bar-Cohen, Y Lih, SS BE BarCohen, Y TI Measurements and macro models of ionomeric polymer-metal composites (IPMC) SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE electroactive polymer; EAP; ionomeric polymer-metal composite; IPMC; actuators; macro model; material characterization ID ELECTROLYTE ACTUATOR AB lonomeric Polymer-Metal Composites (IPMC) are attractive type of electroactive polymer actuation materials because of their characteristics of large electrically induced bending, mechanical flexibility, low excitation voltage, low density, and ease of fabrication. The diffusion of ions between the electrodes causes the material to bend. The unique features of the IPMC materials and their need for special operating environment require new approaches to measuring their characteristics. A macro model that relates the electric input and mechanical output is required for the material characterization and application. This paper addresses the macro models for the electric inputs and electromechanical actuation of IPMC. A distributed RC line model is developed to describe the 'varying capacitance' of the electric input behavior and a four-parameter model to express the relaxation phenomena. The power capacities of the IPMCs are estimated according to the established models and the measured results. Results for several types of IPMCs, which present different behaviors, are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bao, XQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 67-119, Pasadena, CA 91109 USA. NR 7 TC 36 Z9 36 U1 0 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 0-8194-4443-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4695 BP 220 EP 227 DI 10.1117/12.475167 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700024 ER PT S AU Sherrit, S Olazabal, V Sansinena, JM Bao, X Chang, Z Bar-Cohen, Y AF Sherrit, S Olazabal, V Sansinena, JM Bao, X Chang, Z Bar-Cohen, Y BE BarCohen, Y TI The use of piezoelectric resonators for the characterization of mechanical properties of polymers SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE piezoelectric devices; active materials; thin film resonators; composite resonators; quartz crystal microbalance ID IMAGINARY MATERIAL CONSTANTS; THICKNESS MODE; TRANSDUCERS; FREQUENCY; CERAMICS; ELEMENT; REAL AB In this paper a variety of techniques to characterize the mechanical properties of polymers in the MHz frequency range based on the impedance analysis of thickness and thickness shear composite resonators will be presented. The analysis is based on inverting the impedance data of the composite, resonator to find the best fit using the material coefficients of the piezoelectric resonator and attached polymer layer. Mason's equivalent circuit is used along with standard acoustic circuit elements to generate the impedance of the composite resonators and interpret the experimental data. Inversion techniques will be presented which allow for the direct determination of the acoustic load if the material properties of the resonator are known before being joined to the polymer. A specific example of this technique, the quartz crystal microbalance will be presented and it will be shown how the model can be extended to include all the acoustic elements of the experimental setup including the acoustic load of the solution. In the model all elements are treated as complex to account for loss mechanisms (viscous effects, electric dissipation etc.). If the free resonator is modeled prior to deposition a transform is presented that allows for the determination of the acoustic load directly. The advantage being that one no longer has to assume a functional form of the acoustic load (eg. mass damping) since it can be measured directly and compared to the various models. In addition the transform allows for an easy determination of the mass sensitivity and bandwidth for the system. The theory can be extended to account for electrode mass changes (adsorption/condensation and desertion/evaporation) or for use in chemical monitoring by the addition of a chemically sensitive layer (artificial noses and tongues). The technique has also applications for the direct determination of the elastic coefficients of polymer materials. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Sherrit, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA USA. NR 26 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 0-8194-4443-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4695 BP 262 EP 276 DI 10.1117/12.475175 PG 15 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700029 ER PT S AU Bar-Cohen, Y Bao, XQ Sherrit, S Lih, SS AF Bar-Cohen, Y Bao, XQ Sherrit, S Lih, SS BE BarCohen, Y TI Characterization of the electromechanical properties of ionomeric polymer-metal composite (IPMC) SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE Proceedings of SPIE LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE EAP; characterization; testing; electromechanical properties; electroactive polymers; actuators ID ARTIFICIAL MUSCLES AB IPMC is an electroactive polymer (EAP) that has been the subject of research and development since 1992. The advantages of IPMC in requiring low activation voltage and the induced large bending strain led to its consideration for various potential applications. However, before the benefits of IPMC can be effectively exploited for practical use, the electromechanical behavior of this group of EAP materials must be properly understood and quantified. An experimental setup was developed for data acquisition from IPMC strips that are subjected to various tip mass load levels. This data acquisition setup was used to measure the displacement and curvature of IPMC as a function of the input signal. Sample strips were immersed in water to minimize the effect of moisture content. In order to avoid electrolysis, the samples were subjected to 1-V square wave with either positive or negative polarity. Experiments have shown that IPMC has history dependence and the characteristics response is dominated by the backbone (e.g., Nafion, Flemion, etc.) and ionic content (e.g., Na+, Li+, etc.). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 82-105, Pasadena, CA 91109 USA. EM yosi@jpl.nasa.gov NR 9 TC 22 Z9 22 U1 0 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 0-8194-4443-X J9 PROC SPIE PY 2002 VL 4695 BP 286 EP 293 DI 10.1117/12.475173 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700031 ER PT S AU Thomsen, DL Bush, G Keller, P Bryant, RG AF Thomsen, DL Bush, G Keller, P Bryant, RG BE BarCohen, Y TI Thermally actuated polymer benders SO SMART STRUCTURES AND MATERIALS 2002: ELECTROACTIVE POLYMER ACTUATORS AND DEVICES (EAPAD) SE Proceedings of SPIE LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE actuator; liquid crystalline elastomer; thermally active polymer ID LIQUID-CRYSTAL ELASTOMERS AB A thermally driven liquid crystalline elastomer bending actuator was prepared with extended cycling capabilities. This device operated with strain rates of 1 Hz displacement and 0.13 Hz recovery starting from 25.1 degreesC to a maximum of 150 degreesC. The device is a bending actuator having a multilaminated material structure. Observed displacements were lower than previous freestanding liquid crystalline elastomer films due to the constraints imposed on the liquid crystalline elastomer by the device architecture. A device operated with low power of less than 2 W and cycled over a 1000 times successfully. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Thomsen, DL (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, 6A W Taylor ST,MS 226, Hampton, VA 23681 USA. EM d.l.thomsen@larc.nasa.gov NR 11 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 0-8194-4443-X J9 PROC SPIE PY 2002 VL 4695 BP 435 EP 441 DI 10.1117/12.475191 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Composites; Robotics; Optics; Polymer Science SC Engineering; Materials Science; Robotics; Optics; Polymer Science GA BV10E UT WOS:000177817700047 ER PT S AU McGowan, AMR Washburn, AE Horta, LG Bryant, RG Cox, DE Siochi, EJ Padula, SL Holloway, NM AF McGowan, AMR Washburn, AE Horta, LG Bryant, RG Cox, DE Siochi, EJ Padula, SL Holloway, NM BE McGowan, AMR TI Recent results from NASA's Morphing Project SO SMART STRUCTURES AND MATERIALS 2002: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE smart materials; smart structures; micro flow control; biomimetics; adaptability; morphing ID FLOW-CONTROL; ACTUATORS AB The NASA Morphing Project seeks to develop and assess advanced technologies and integrated component concepts to enable efficient, multi-point adaptability in air and space vehicles. In the context of the project, the word "morphing" is defined as "efficient, multi-point adaptability" and may include macro, micro, structural and/or fluidic approaches. The project includes research on smart materials, adaptive structures, micro flow control, biomimetic concepts, optimization and controls. This paper presents an updated overview of the content of the Morphing Project including highlights of recent research results. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP McGowan, AMR (reprint author), NASA, Langley Res Ctr, Mail Stop 254, Hampton, VA 23681 USA. NR 92 TC 24 Z9 24 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 0-8194-4446-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4698 BP 97 EP 111 DI 10.1117/12.475056 PG 15 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BV06K UT WOS:000177732700010 ER PT S AU Holloway, NMH Barnes, KN Draughon, GK Scott, LA AF Holloway, NMH Barnes, KN Draughon, GK Scott, LA BE McGowan, AMR TI Fabrication of adhesiveless lightweight flexible circuits using Langley Research Center soluble-imide "LaRC-SI" polyimide film SO SMART STRUCTURES AND MATERIALS 2002: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE flexible circuits; adhesiveless; compliant substrate; multifunctional structures AB Electronics that support aircraft military, and space applications, as well as the consumer portables industry are increasingly calling for lighter-weight systems. With this, flex circuits are being used in lieu of heavier weight rigid circuit boards and flex is finding its way into increased applications. Flex offers a substrate material that is significantly lighter in weight, thinner, and more compliant than traditional rigid circuit board materials. Numerous methods of fabricating multilayer flex circuits exist; most of which involve using an adhesive material to bond the individual patterned film layers together to create the multilayer circuit. Thus adhesives are commonly used to bond conductive foils to polyimide films, cover-layers to patterned circuits, and patterned films together to form multilayer circuits. However, adhesives can be problematic if they fail, ultimately leading to wrinkling, voids or delamination of the circuit. Numerous advantages can be gained from fabricating flex circuits without adhesives. Some of these advantages include: a reduction of materials and processing costs, lighter end-weight circuits, increased circuit flexibility, circuits with less z-axis expansion, and a matched coefficient of thermal expansion between the circuit layers. NASA Langley Research Center has developed a unique polyimide material called Langley Research Center-Soluble Polyimide or "LaRC-SI" which can be used to make lightweight, adhesiveless flex circuits. LaRC-SI films can be bonded together simply by applying heat and pressure, and require no additional adhesive material for lamination. Once the LaRC-SI films are heated and pressed together, the individual films fuse together forming a monolithic film Additionally, LaRC-SI flex circuits can be bonded directly to structures without the use of adhesives, simply by using a thermal compression technique. This technique provides a means of fabricating a multifunctional structure with many advantages, among the most obvious being optimized use of space. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Holloway, NMH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 21 TC 1 Z9 1 U1 2 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4446-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4698 BP 293 EP 303 DI 10.1117/12.475076 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BV06K UT WOS:000177732700029 ER PT S AU Shams, QA Barnes, KN Fox, RL Moses, RW Bryant, RG Robinson, P Shirvani, MS AF Shams, QA Barnes, KN Fox, RL Moses, RW Bryant, RG Robinson, P Shirvani, MS BE McGowan, AMR TI Small and lightweight power amplifiers SO SMART STRUCTURES AND MATERIALS 2002: INDUSTRIAL AND COMMERCIAL APPLICATIONS OF SMART STRUCTURES TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE control; vibration; small; lightweight; design; power amplifier AB The control of unwanted structural vibration is implicit in most of NASA's programs. Currently several approaches to control vibrations in large, lightweights deployable structures and twin tail aircraft at high angles of attack are being evaluated. The Air Force has been examining a vertical tail buffet load alleviation system that can be integrated onboard an F/A-18 and flown. Previous wind tunnel and full-scale ground tests using distributed actuators have shown that the concept works; however, there is insufficient room available onboard an F/A-18 to store current state-of-the-art system components such as amplifiers, DC-to-DC converter and a computer for performing vibration suppression. Sensor processing, power electronics, DC-to-DC converters, and control electronics that may be collocated with distributed actuators, are particularly desirable. Such electronic systems would obviate the need for complex, centralized, control processing and power distribution components that will eliminate the weight associated with lengthy wiring and cabling networks. Several small and lightweight power amplifiers ranging from 300V pp to 650V pp have been designed using off the shelf components for different applications. In this paper, the design and testing of these amplifiers will be presented under various electrical loads. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Shams, QA (reprint author), NASA, Langley Res Ctr, Mail Stop 236, Hampton, VA 23681 USA. NR 9 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 0-8194-4446-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4698 BP 304 EP 312 DI 10.1117/12.475077 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Instruments & Instrumentation; Materials Science, Composites SC Engineering; Instruments & Instrumentation; Materials Science GA BV06K UT WOS:000177732700030 ER PT S AU Choi, SH Song, KD King, GC Woodall, C AF Choi, SH Song, KD King, GC Woodall, C BE Varadan, VK TI Rectenna performances for smart membrane actuators SO SMART STRUCTURES AND MATERIALS 2002: SMART ELECTRONICS, MEMS, AND NANOTECHNOLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE smart actuators; rectenna; and power allocation and distribution ID SURFACE AB The patch rectenna array was initially designed for high voltage output in shape control applications. The test results show that more than 200 volts of output was obtained from a 6 x 6 array at a far-field exposure (1.8 meters away) with an x-band input power of 18 watts. The 6 x 6 array patch rectenna was designed to generate theoretical voltages of up to 540 volts.. but normal output was range 200 and 300 volts. Test were also performed with a THUNDER actuator attached to the 6 x 6 array. Flexible dipole rectenna arrays built on thin-film based flexible membranes are envisioned as the best option for NASA applications, such as microwave-driven shape controls for aircraft morphing and large ultra lightweight space structures. An array of dipole rectennas was designed for a high voltage output by densely populating it with Schottky barrier diodes to drive piezoelectric or electrostrictive actuators. The dipole rectenna array will eventually be integrated with a PAD logic circuit for power allocation and distribution and microbatteries for storage of excess power. The development of rectenna array-based wireless power drivers for shape control requires the development of new membrane materials with dielectric constants that are suitable for dipole rectenna arrays. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Choi, SH (reprint author), NASA, Langley Res Ctr, Mail Stop 188B, Hampton, VA 23681 USA. NR 17 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 0-8194-4448-0 J9 P SOC PHOTO-OPT INS PY 2002 VL 4700 BP 213 EP 221 DI 10.1117/12.475033 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BV10F UT WOS:000177817800022 ER PT S AU Lekki, J Adamovsky, G Flanagan, P Weiland, K AF Lekki, J Adamovsky, G Flanagan, P Weiland, K BE Davies, LP TI Evaluation of mechanical modal characteristics using optical techniques SO SMART STRUCTURES AND MATERIALS 2002: SMART STRUCTURES AND INTEGRATED SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE fiber optics; sensors; holography; modal analysis; damage detection AB In this paper the sensitivity of embedded fiber optic sensors to changes in modal characteristics of plates is discussed. In order to determine the feasibility of embedded fiber Bragg gratings for the detection of modal shapes and modal frequencies, a comparison of holographically imaged modes and the detected dynamic strain from embedded fiber optic Bragg gratings is made. Time averaged optical holography is used for the detection of mechanical defects, or damage, in various aerospace components. The damage is detected by measuring an alteration in structural dynamics, which is visually apparent when using time-averaged holography. These shifts in the mode shapes, both in frequency of the resonance and spatial location of vibration nodes, are caused by changes in parameters that affect the structure's mechanical impedance, such as stiffness, mass and damping, resulting from cracks or holes. It is anticipated that embedded fiber optic sensor arrays may also be able to detect component damage by sensing these changes in modal characteristics. This work is designed to give an initial indication to the feasibility of damage detection through the monitoring of modal frequencies and mode shapes with fiber optic sensors. C1 NASA, Glenn Res Ctr, Brookpark, OH 44135 USA. RP Lekki, J (reprint author), NASA, Glenn Res Ctr, 21000 Brook Pk Rd, Brookpark, OH 44135 USA. NR 5 TC 1 Z9 1 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 0-8194-4449-9 J9 P SOC PHOTO-OPT INS PY 2002 VL 4701 BP 118 EP 126 DI 10.1117/12.474652 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BV16N UT WOS:000178040800013 ER PT S AU Sherrit, S Askins, SA Gradziol, M Dolgin, BP Bao, XQ Chang, ZS Bar-Cohen, Y AF Sherrit, S Askins, SA Gradziol, M Dolgin, BP Bao, XQ Chang, ZS Bar-Cohen, Y BE Davies, LP TI Novel horn designs for ultrasonic/sonic cleaning welding, soldering, cutting and drilling SO SMART STRUCTURES AND MATERIALS 2002: SMART STRUCTURES AND INTEGRATED SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE piezoelectric devices; ultrasonic/sonic driller/corer (USDC); inverse horn; folded horn; ultrasonic drilling; planetary exploration; piezoelectric devices; Active Materials AB A variety of Industrial applications exist where power ultrasonic elements such as the ultrasonic horn are used. These included the Automotive, Instruments, Foods, Medical, Textiles and Material Joining and Fabrication Industries. In many of these devices the ultrasonic horn is the key component. The standard transducer used in these devices consists of three main parts, the backing, the piezoelectric elements and the horn. Standard horn designs have changed very little since their inception. There are four common types of standard horns. They are; constant, linear, exponential and stepped, which refer to the degree to which the area changes from the base to the tip. A magnification in the strain occurs in the horn that in general is a function of the ratio of diameters. In addition the device is generally driven at resonance to further amplify the strain. The resonance amplification is in general determined by the mechanical Q (attenuation) of the horn material and radiation damping. The horn length primarily determines the resonance frequency. For a 22 kHz resonance frequency a stepped horn of titanium has a length of approximately 8 cm. Although these standard horns are found in many current industrial designs they suffer from some key limitations. In many applications it would be useful to reduce the resonance frequency however this would require device lengths of the order of fractions of meters which may be impractical. In addition, manufacturing a horn requires the turning down of the stock material (eg. Titanium) from the larger outer diameter to the horn tip diameter, which is both time consuming and wasteful. In this paper we will present a variety of novel horn designs, which overcome some of the limitations discussed above. One particular design that has been found to overcome these limitations is the folded horn. In this design the horn elements are folded which reduce the overall length of the resonator (physical length) but maintain or increase the acoustic length. In addition initial experiments indicate that the tip displacement can be further adjusted by phasing the bending displacements and the extensional displacements. The experimental results for a variety of these and other novel horn designs will be presented and compared to the results predicted by theory. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Sherrit, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 8 TC 3 Z9 3 U1 0 U2 13 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4449-9 J9 P SOC PHOTO-OPT INS PY 2002 VL 4701 BP 353 EP 360 DI 10.1117/12.474671 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BV16N UT WOS:000178040800033 ER PT S AU Chang, ZS Dolgin, B Bao, XQ Sherrit, S Bar-Cohen, Y AF Chang, ZS Dolgin, B Bao, XQ Sherrit, S Bar-Cohen, Y BE Davies, LP TI Modeling of particle flow due to ultrasonic drilling SO SMART STRUCTURES AND MATERIALS 2002: SMART STRUCTURES AND INTEGRATED SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE ultrasonic/sonic driller/corer (USDC); particle flow in-situ sampling; ultrasonic drilling; planetary exploration; piezoelectric devices; Active Materials AB In-situ sampling and analysis is one of the major tasks in future NASA exploration missions. It is essential that the samples acquired on other planets including Mars are free of contaminations from the earth. Recently, a novel drilling technology that is actuated by a piezoelectric drive mechanism was developed and it is called Ultrasonic/Sonic Driller/Corer (USDC). This drill has an inherent capability to extract the formed drilling powder and thus addresses the critical issue of contamination. A modification of this USDC in the form of an Ultrasonic Rock Abrasion Tool (URAT) allows for the formation of pristine rock surface for analysis. An algorithm is being proposed for the reduction of the contamination that may be generated during the acquisition of the samples. The algorithm could be used to control the flow of particles using programmed vibration characteristics and thus allows for smart flow of particles. The hypothesis is that the probability of a contamination left on the ground surface is exponentially inverse-proportional to the volume of the core ground into dusts. To support this hypothesis, we need to understand the flow pattern of the particles. A model proposed by Savage [1988] is used to develop a computer program using finite difference method. Some preliminary results have been derived. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chang, ZS (reprint author), CALTECH, Jet Prop Lab, MS 67-119,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 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 0-8194-4449-9 J9 P SOC PHOTO-OPT INS PY 2002 VL 4701 BP 361 EP 367 DI 10.1117/12.474672 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BV16N UT WOS:000178040800034 ER PT S AU Bao, XQ Chang, ZS Sherrit, S Dolgin, BP Bar-Cohen, Y AF Bao, XQ Chang, ZS Sherrit, S Dolgin, BP Bar-Cohen, Y BE Davies, LP TI Analysis and simulation of the ultrasonic/sonic driller/corer(USDC) SO SMART STRUCTURES AND MATERIALS 2002: SMART STRUCTURES AND INTEGRATED SYSTEMS SE Proceedings of SPIE LA English DT Proceedings Paper CT Smart Structures and Materials 2002 Conference CY MAR 18-21, 2002 CL SAN DIEGO, CA SP SPIE, Amer Soc Mech Engineers, Soc Exptl Mech, Boeing Co, Rhombus Consultants Grp, CSA Engn, ISIS Canada, USAF Off Sci Res, Def Adv Res Projects Agcy, Intelligent Mat Forum, USA Res OFf, Jet Propuls Lab, Natl Sci Fdn, Ceram Soc Japan, USN Off Naval Res, Nav Res Lab DE piezoelectric ultrasonic drill; piezoelectric actuators; rock sampling; FE analysis; numerical simulation ID TRANSDUCERS AB An ultrasonic/sonic driller/corer (USDC) was developed to address the challenges to the NASA objective of planetary in-situ rock sampling and analysis. The USDC uses a novel drive mechanism, transferring ultrasonic vibration into impacts on a drill stem at sonic frequency using a free-flying mass block (free-mass). The main parts of the device and the interactions between them were analyzed and numerically modeled to understand the drive mechanism and allow design of effective drilling mechanism. A computer program was developed to simulate the operation of the USDC and successfully predicted the characteristic behavior of the new device. This paper covers the theory, the analytical models and the algorithms that were developed and the predicted results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bao, XQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS67-119, Pasadena, CA 91125 USA. EM xbao@jpl.nasa.gov NR 9 TC 0 Z9 0 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 0-8194-4449-9 J9 PROC SPIE PY 2002 VL 4701 BP 368 EP 379 DI 10.1117/12.474673 PG 12 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BV16N UT WOS:000178040800035 ER PT S AU Grant, J Kaul, R Taylor, S Myer, G Jackson, K Sharma, A AF Grant, J Kaul, R Taylor, S Myer, G Jackson, K Sharma, A BE Harvey, EC Abbott, D Varadan, VK TI Distributed sensing of carbon-epoxy composites and filament wound pressure vessels using Fiber-Bragg gratings SO SMART STRUCTURES, DEVICES, AND SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Smart Materials, Nano-, and Micro-Smart Systems CY DEC 16-18, 2002 CL RMIT UNIV, MELBOURNE, AUSTRALIA SP SPIE, Univ Arkansas, Natl Inst Adv Ind Sci & Technol, Cooperat Res Ctr Microtechnol, Dept Def, Australia, Swinburne Univ Technol, Adelaide Univ, Japanese Soc Electr Packaging, New Energy & Ind Technol Dev Org HO RMIT UNIV ID STRAIN AB Multiple Fiber Bragg-gratings are embedded in carbon-epoxy laminates as well as in composite, wound pressure vessel. Structural properties of such composites are investigated. The measurements include stress-strain relation in laminates and Poisson's: ratio in several specimens with varying orientation of the optical fiber Bragg-sensor with respect to the carbon fiber in an epoxy matrix. Additionally, fiber Bragg gratings are bonded on the surface of these laminates and cylinders fabricated out of carbon-epoxy composites and multiple points are monitored and compared for strain measurements at several locations. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Grant, J (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 5 TC 4 Z9 4 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 0-8194-4730-7 J9 P SOC PHOTO-OPT INS PY 2002 VL 4935 BP 32 EP 40 DI 10.1117/12.469076 PG 9 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BW30Z UT WOS:000181494600004 ER PT S AU Zheng, Y Cheng, SF Fettig, R Li, M Mott, B Moseley, H AF Zheng, Y Cheng, SF Fettig, R Li, M Mott, B Moseley, H BE Harvey, EC Abbott, D Varadan, VK TI Film stress of microshutter arrays for the James Webb Space Telescope SO SMART STRUCTURES, DEVICES, AND SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT International Symposium on Smart Materials, Nano-, and Micro-Smart Systems CY DEC 16-18, 2002 CL RMIT UNIV, MELBOURNE, AUSTRALIA SP SPIE, Univ Arkansas, Natl Inst Adv Ind Sci & Technol, Cooperat Res Ctr Microtechnol, Dept Def, Australia, Swinburne Univ Technol, Adelaide Univ, Japanese Soc Electr Packaging, New Energy & Ind Technol Dev Org HO RMIT UNIV AB The James Webb Space Telescope (JWST), formally Next Generation Space Telescope (NGST), is one of NASA's challenging projects for advancing the exploration of space. The NGST will be equipped with a Multi-Object-Spectrometer (MOS) that covers the wavelength ranging from 0.6 to 5 micron. To selectively direct light rays from different regions of space into the spectrometer, one approach is to use microshutter arrays serving as the slit mask for the spectrometer. A large format (2Kx1K) individually addressable microshutter array with a lateral pixel size of 100mum x 200mum is being developed and fabricated using MEMS technologies. The microshutter arrays are close-packed silicon nitride membrane cantilevers. A ferromagnetic Co90Fe10 film is deposited on the membranes to magnetically actuate the microshutters. During deposition a Co90Fe10 film is susceptible to develop large tensile stress that can distort the nitride membranes and affect the contrast of the MOS, especially at cryogenic temperatures. In this paper, we discuss how to minimize the film stress. Stress-test cantilevers are micro machined and used in conjunction with Stoney's formula to determine film stresses. The effects of deposition pressure and power on the Co90Fe10 film, aluminum film and multiple-layer film stress are discussed. It is found that sputter-deposition of Co90Fe10 at low pressure and power results in favor of low tensile stresses in films. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zheng, Y (reprint author), NASA, Goddard Space Flight Ctr, Code 553, Greenbelt, MD 20771 USA. NR 7 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 0-8194-4730-7 J9 P SOC PHOTO-OPT INS PY 2002 VL 4935 BP 279 EP 286 DI 10.1117/12.476118 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BW30Z UT WOS:000181494600032 ER PT B AU Wolpert, DH AF Wolpert, DH BE Roy, R Koppen, M Ovaska, S Furuhashi, T Hoffman, F TI The supervised learning no-free-lunch theorems SO SOFT COMPUTING AND INDUSTRY: RECENT APPLICATIONS LA English DT Proceedings Paper CT 6th On-Line World Conference on Soft Computing in Industrial Applications (WSC6) CY SEP, 2001 CL ELECTR NETWORK ID A-PRIORI DISTINCTIONS; ALGORITHMS AB This paper reviews the supervised learning versions of the no-free-lunch theorems in a simplified form. It also discusses the significance of those theorems, and their relation to other aspects of supervised learning. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wolpert, DH (reprint author), NASA, Ames Res Ctr, MS 269-1, Moffett Field, CA 94035 USA. NR 15 TC 14 Z9 14 U1 0 U2 3 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 1-85233-539-4 PY 2002 BP 25 EP 42 PG 18 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BV31Y UT WOS:000178582500003 ER PT S AU Mewaldt, RA Cohen, CMS Leske, RA Christian, ER Cummings, AC Stone, EC von Rosenvinge, TT Wiedenbeck, ME AF Mewaldt, RA Cohen, CMS Leske, RA Christian, ER Cummings, AC Stone, EC von Rosenvinge, TT Wiedenbeck, ME BE Simnett, GM TI Fractionation of solar energetic particles and solar wind according to first ionization potential SO SOLAR COMPOSITION: NEW PERSPECTIVES FROM IN-SITU AND REMOTE SENSING STUDIES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D2 1-E3 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL 16-23, 2000 CL WARSAW, POLAND SP Comm Space Res ID IONIC CHARGE STATES; ABUNDANCES; ULYSSES AB Although it is well known that solar energetic particles are depleted in elements with first ionization potential (FIP) greater than similar to10 eV, it is less well known that the degree of FIP fractionation varies from event to event. Similar fractionation patterns and variations are observed in the solar wind, suggesting that these variations may have a common origin. We review evidence for the FIP-related fractionation of SEPs and compare it with FIP fractionation effects in the solar wind at 1 AU. On the basis of several significant differences between the solar wind and SEP compositions, we suggest that most solar energetic particles are not simply an accelerated sample of the average solar wind as observed at 1 AU; rather, solar particles and fast and slow solar wind appear to be distinct samples of coronal material with distinctly different FIP-fractionation patterns. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mewaldt, RA (reprint author), CALTECH, Pasadena, CA 91125 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 22 TC 13 Z9 13 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 1 BP 79 EP 84 AR PII S0273-1177(02)00263-6 DI 10.1016/S0273-1177(02)00263-6 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV03R UT WOS:000177664600010 ER PT S AU Slocum, PL Wiedenbeck, ME Christian, ER Cohen, CMS Cummings, AC Leske, RA Mewaldt, RA Stone, EC von Rosenvinge, TT AF Slocum, PL Wiedenbeck, ME Christian, ER Cohen, CMS Cummings, AC Leske, RA Mewaldt, RA Stone, EC von Rosenvinge, TT BE Simnett, GM TI Energetic particle composition at 1 Au during periods of moderate interplanetary particle fluxes SO SOLAR COMPOSITION: NEW PERSPECTIVES FROM IN-SITU AND REMOTE SENSING STUDIES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D2 1-E3 2 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly CY JUL 16-23, 2000 CL WARSAW, POLAND SP Comm Space Res ID SOLAR; EVENTS; HE-3; ABUNDANCES AB It has recently been proposed that residual energetic ions from preceding impulsive solar energetic particle (SEP) events may contribute to the source population for the larger gradual events accelerated by CME-driven shocks (Mason et al., 1999). This suggests that there may be impulsive SEP material left in interplanetary space during periods relatively free of energetic particle activity. To test this idea we have studied the heavy ions and He-3 present at L1 during periods of low-to-moderate energetic particle fluxes between February 1998 and April 2000. Using the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have measured the energy spectra of heavy elements (Zgreater than or equal to6) and He-3 over the ranges similar to8-20 MeV/nucleon and similar to4-15 MeV/nucleon, respectively. In these energy spectra, we have looked for spectral and compositional signatures typically characteristic of impulsive or gradual SEP events. We discuss the implications of these observations for the origin of particles accelerated in gradual SEP events. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. RP Slocum, PL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 16 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 1 BP 97 EP 104 AR PII S0273-1177(02)00264-8 DI 10.1016/S0273-1177(02)00264-8 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV03R UT WOS:000177664600013 ER PT J AU Hathaway, DH Beck, JG Han, S Raymond, J AF Hathaway, DH Beck, JG Han, S Raymond, J TI Radial flows in supergranules SO SOLAR PHYSICS LA English DT Article ID STEADY PHOTOSPHERIC FLOWS; SPHERICAL HARMONIC-ANALYSIS; SOLAR PHOTOSPHERE; CONVECTION AB We determine the radial component of the supergranular flow velocity by examining the center-to-limb variation of the Doppler velocity signal. We acquire individual Doppler images obtained with the MDI instrument on the SOHO spacecraft and process them to remove the p-mode oscillation signal, the axisymmetric flows, the convective blueshift signal, and instrumental artifacts. The remaining Doppler signal contains only non-axisymmetric flow structures. The Doppler signal from the horizontal flows in these structures varies like sin rho, where rho is the heliocentric angle from disk center. The Doppler signal from radial flows varies like cos rho. We fit the center-to-limb variation of the mean squared velocity signal to a straight line in sin(2) rho over the central portion of the disk. The intercept of this line at disk center gives the amplitude of the radial component of the flow. The slope of the line gives the amplitude of the horizontal component. We find that the radial flows for typical supergranules have speeds about 10% that of their associated horizontal flows or about 30 m s(-1). The ratio of the radial to horizontal flow speed increases from 9% to about 18% as the size of the structure decreases from > 60 Mm to similar to5 Mm. We use data simulations to check these results and find a ratio that increases from 5% to only about 12% over the same range of sizes. These smaller ratios are attributed to an underestimation of the horizontal flow speeds due to the fact that the transverse component of the horizontal flow is not detected by Doppler measurements. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Stanford Univ, Stanford, CA 94305 USA. Tennessee Technol Univ, Cookeville, TN 38505 USA. RP Hathaway, DH (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 24 TC 39 Z9 39 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 2002 VL 205 IS 1 BP 25 EP 38 DI 10.1023/A:1013881213279 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 539UL UT WOS:000174889800002 ER PT J AU Torsti, J Kocharov, L Laivola, J Pohjolainen, S Plunkett, SP Thompson, BJ Kaiser, ML Reiner, MJ AF Torsti, J Kocharov, L Laivola, J Pohjolainen, S Plunkett, SP Thompson, BJ Kaiser, ML Reiner, MJ TI Solar particle events with helium-over-hydrogen enhancement in the energy range up to 100 MeV nucl(-1) SO SOLAR PHYSICS LA English DT Article ID GAMMA-RAY SPECTROSCOPY; CORONAL MASS EJECTION; X-RAY; FLARE; ABUNDANCES; WIND; MISSION; ACCELERATION; SIMULATIONS; ATMOSPHERE AB Flux measurements of solar energetic particles (SEPs) in the ERNE instrument onboard SOHO indicate that the abundance of He-4-nuclei compared to protons in the energy range up to 100 MeV nucl(-1) was exceptionally high during the particle events on 27 May 1998 and 28 December 1999. The He-4/p ratio stayed between 0.15-0.50 for more than ten hours. There was also a prolonged enhancement in helium-3, He-3/H-4 approximate to 1%. Observations of EIT and LASCO on board SOHO confirm that the originators of both SEP events were western eruptions, flares and coronal mass ejections (CMEs). The onset of the SEP release took place close to the maximum of flares which Were probably triggered by the rising CMEs. The observations suggest that the SEP events were started with the flare-(pre)accelerated particles, but impact of the CME-associated shocks might explain the continuation and modification of the helium and proton fluxes well after the flare production. These observations support the idea that the helium enhancements in the CME-associated events reflect the availability of seed particles that originate previously in flares. C1 Univ Turku, Dept Phys, Space Res Lab, FIN-20014 Turku, Finland. Univ Turku, Tuorla Observ, FIN-21500 Piikkio, Finland. USN, Res Lab, Univ Space Res Assoc, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS, Lanham, MD 20706 USA. RP Torsti, J (reprint author), Univ Turku, Dept Phys, Space Res Lab, FIN-20014 Turku, Finland. RI Thompson, Barbara/C-9429-2012 NR 63 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 2002 VL 205 IS 1 BP 123 EP 147 DI 10.1023/A:1013816929208 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 539UL UT WOS:000174889800009 ER PT B AU Brekke, P AF Brekke, P BE Wang, HN Xu, RL TI Space weather effects and how SOHO has improved the warnings SO SOLAR-TERRESTRIAL MAGNETIC ACTIVITY AND SPACE ENVIRONMENT SE COSPAR COLLOQUIA SERIES LA English DT Proceedings Paper CT Colloquium on Solar-Terrestrial Magnetic Activity and Space Environment CY SEP 10-12, 2001 CL CHINESE ACAD SCI, NATL ASTRON OBSERV, BEIJING, PEOPLES R CHINA SP COSPAR Chinese Natl Comm, Comm Space Res, Natl Nat Sci Fdn China, Minist Sci & Technol HO CHINESE ACAD SCI, NATL ASTRON OBSERV ID EARTH AB Transient variations in the particle and EUV flux from the Sun cause disturbances in the Earth's space environment affecting some of the technologies that we depend on both in orbit and on the ground. Both, the increasing deployment of radiation-, current-, and field-sensitive technological systems over the last few decades and the increasing presence of complex systems in space, combine to make society more vulnerable to solar-terrestrial disturbances. Thus, today our society is much more sensitive to space weather activity than it was during the last solar maximum. The Solar and Heliospheric Observatory (SOHO) has obtained significant new information about coronal mass ejections (CMEs), the source of the most severe disturbances in the Earth's environment. Furthermore, by observing the Sun 24 hours a day, SOHO has proved to be an important "space weather watchdog". The importance of real-time monitoring of the Sun is pointed out and a number of enterprises affected by space weather are discussed. C1 NASA, Goddard Space Flight Ctr, ESA Space Sci Dept, Greenbelt, MD 20771 USA. RP Brekke, P (reprint author), NASA, Goddard Space Flight Ctr, ESA Space Sci Dept, Code 682-3, Greenbelt, MD 20771 USA. NR 8 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 0-08-044110-6 J9 COSPAR COLL PY 2002 VL 14 BP 385 EP 392 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BW25F UT WOS:000181336400067 ER PT S AU Kosovichev, AG Duvall, TL Birch, AC Gizon, L Scherrer, PH Zhao, JW AF Kosovichev, AG Duvall, TL Birch, AC Gizon, L Scherrer, PH Zhao, JW BE Frohlich, C Pap, JM Dame, L Marsch, E TI Local-area helioseismology as a diagnostic tool for solar variability SO SOLAR VARIABILITY AND SOLAR PHYSICS MISSIONS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 3/E2 4 Symposia of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP European Space Agcy, Int Astron Union, Comm Space Res ID TIME-DISTANCE HELIOSEISMOLOGY AB Dynamical and thermal variations of the internal structure of the Sun can affect the energy flow and result in variations in irradiance at the surface. Studying variations in the interior is crucial for understanding the mechanisms of the irradiance variations. "Global" helioseismology based on analysis of normal mode frequencies, has helped to reveal radial and latitudinal variations of the solar structure and dynamics associated with the solar cycle in the deep interior. A new technique, - "local-area" helioseismology or heliotomography, offers additional potentially important diagnostics by providing three-dimensional maps of the sound speed and flows in the upper convection zone. These diagnostics are based on inversion of travel times of acoustic waves which propagate between different points on the solar surface through the interior. The most significant variations in the thermodynamic structure found by this method are associated with sunspots and complexes of solar activity. The inversion results provide evidence for areas of higher sound speed beneath sunspot regions located at depths of 4-20 Mm, which may be due to accumulated heat or magnetic field concentrations. However, the physics of these structures is not yet understood. Heliotomography also provides information about large-scale stable longitudinal structures in the solar interior, which can be used in irradiance models. This new diagnostic tool for solar variability is currently under development. It will require both a substantial theoretical and modeling effort and high-resolution data to develop new capabilities for understanding mechanisms of solar variability. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Kosovichev, AG (reprint author), Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. RI Zhao, Junwei/A-1177-2007; Gizon, Laurent/B-9457-2008; Duvall, Thomas/C-9998-2012 NR 16 TC 8 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 12 BP 1899 EP 1910 AR PII S0273-1177(02)00241-7 DI 10.1016/S0273-1177(02)00241-7 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BU89J UT WOS:000177314700003 ER PT S AU Pap, JM Turmon, M Floyd, L Frohlich, C Wehrli, C AF Pap, JM Turmon, M Floyd, L Frohlich, C Wehrli, C BE Frohlich, C Pap, JM Dame, L Marsch, E TI Total solar and spectral irradiance variations from solar cycles 21 to 23 SO SOLAR VARIABILITY AND SOLAR PHYSICS MISSIONS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 3/E2 4 Symposia of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP European Space Agcy, Int Astron Union, Comm Space Res ID CLIMATE-CHANGE; VARIABILITY; LUMINOSITY; VIRGO; TIME; SOHO AB Total solar and UV irradiances have been measured from various space platforms for more than two decades. More recently, observations of the "Variability of solar IRradiance and Gravity Oscillations" (VIRGO) experiment on SOHO provided information about spectral irradiance variations in the near-UV at 402 nm, visible at 500 nm, and near-IR at 862 nm. Analyses based on these space-borne irradiance measurements have convinced the skeptics that solar irradiance at various wavelengths and in the entire spectrum is changing with the waxing and waning solar activity. The main goal of this paper is to review the short- and long-term variations in total solar and spectral irradiances and their relation to the evolution of magnetic fields from solar cycles 21 to 23. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Angeles, Los Angeles, CA 90024 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Interferometr Inc, Chantilly, VA 20151 USA. Phys Meteorol Observ, CH-7260 Davos, Switzerland. RP Pap, JM (reprint author), Univ Calif Los Angeles, 450 Hilgard Ave, Los Angeles, CA 90024 USA. NR 28 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 12 BP 1923 EP 1932 AR PII S0273-1177(02)00237-5 DI 10.1016/S0273-1177(02)00237-5 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BU89J UT WOS:000177314700006 ER PT S AU Marsch, E Antonucci, E Bochsler, P Bougeret, JL Fleck, B Harrison, R Langevin, Y Marsden, R Pace, O Schwenn, R Vial, JC AF Marsch, E Antonucci, E Bochsler, P Bougeret, JL Fleck, B Harrison, R Langevin, Y Marsden, R Pace, O Schwenn, R Vial, JC BE Frohlich, C Pap, JM Dame, L Marsch, E TI Solar Orbiter, a high-resolution mission to the sun and inner heliosphere SO SOLAR VARIABILITY AND SOLAR PHYSICS MISSIONS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 3/E2 4 Symposia of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP European Space Agcy, Int Astron Union, Comm Space Res AB The scientific rationale of the Solar Orbiter is to provide, at high spatial (35 km pixel size) and temporal resolution, observations of the solar atmosphere and unexplored inner heliosphere. Novel observations will be made in the almost heliosynchronous segments of the orbits at heliocentric distances near 45 R-circle dot and out of the ecliptic plane at the highest heliographic latitudes of 30degrees - 38degrees. The Solar Orbiter will achieve its wide-ranging aims with a suite of sophisticated instruments through an innovative design of the orbit. The first near-Sun interplanetary measurements together with concurrent remote observations of the Sun will permit us to determine and understand, through correlative studies, the characteristics of the solar wind and energetic particles in close linkage with the plasma and radiation conditions in their source regions on the Sun. Over extended periods the Solar Orbiter will deliver the first images of the polar regions and the side of the Sun invisible from the Earth. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Turin, Inst Fis, I-110125 Turin, Italy. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. Observ Paris, LESIA, F-92195 Meudon, France. NASA, Goddard Space Flight Ctr, ESA Res & Space Sci Dept, Greenbelt, MD 20771 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. European Space Technol Ctr, European Space Agcy, NL-2200 AG Noordwijk, Netherlands. RP Marsch, E (reprint author), Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RI Fleck, Bernhard/C-9520-2012 NR 4 TC 13 Z9 13 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 12 BP 2027 EP 2040 AR PII S0273-1177(02)00148-5 DI 10.1016/S0273-1177(02)00148-5 PG 14 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BU89J UT WOS:000177314700021 ER PT S AU Thompson, WT AF Thompson, WT BE Frohlich, C Pap, JM Dame, L Marsch, E TI Standardized coordinate systems for solar image data SO SOLAR VARIABILITY AND SOLAR PHYSICS MISSIONS SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT E2 3/E2 4 Symposia of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP European Space Agcy, Int Astron Union, Comm Space Res AB The current state of describing the coordinates of solar image data is chaotic, and does not take into account the most recent developments in the coordinate systems for astronomy in general, especially as related to FITS files. A set of formal systems for describing the coordinates of solar image data is proposed. These systems build on current practice in applying coordinates to solar image data. Both heliographic and heliocentric coordinates axe discussed. A distinction is also drawn between heliocentric and helioprojective coordinates, where the latter takes the observer's exact geometry into account. The extension of these coordinate systems to observations made from non-terrestial viewpoints, such as STEREO and Solar Probe, is discussed. A formal system for incorporation of these coordinates into FITS files, based on the FITS World Coordinate System, is described. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Emergent IT Inc, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Emergent IT Inc, Code 682-3, Greenbelt, MD 20771 USA. RI Thompson, William/D-7376-2012 NR 5 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2002 VL 29 IS 12 BP 2093 EP 2098 AR PII S0273-1177(02)00155-2 DI 10.1016/S0273-1177(02)00155-2 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BU89J UT WOS:000177314700029 ER PT S AU Fainberg, J Osherovich, VA AF Fainberg, J Osherovich, VA GP ESA ESA TI Solar wind quasi-invariant as a heliospheric index of solar activity SO SOLAR VARIABILITY: FROM CORE TO OUTER FRONTIERS, VOLS 1 & 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Solar Physics Meeting CY SEP 09-14, 2002 CL PRAGUE, CZECH REPUBLIC SP European Commiss, European Phys Soc, European Space Agcy, Astron Inst Acad Sci, Prvni Energeticka a s ID PREDICTION AB Interplanetary magnetic field strength B, solar wind speed v and plasma density _ all vary with sunspot numbers (SSN). The corresponding correlation coefficients (cc) are not high enough to establish any of these parameters as a close proxy for SSN. In contrast, the solar wind quasi-invariant [ QI equivalent to (B-2/ 8pi) /(rhov(2) / 2)] recently suggested by Osherovich, Fainberg and Stone [1999] has a high cc = 0.98 for the median yearly value for the 28 year period measured in the solar wind near the Earth (1 AU). For the period 1978-1989, Voyager 2 measured B, v and rho from 2 AU to 27 AU. In this paper we show that in spite of the orders of magnitude change of B and rho at large heliospheric distances, QI measured by Voyager 2 stayed in the same range and followed SSN similar to QI measured near the Earth and near Venus. These results supply an observational test for any MHD model of the solar wind throughout the heliosphere that attempts to include the effects of solar cycle variability. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fainberg, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 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 92-9092-816-6 J9 ESA SP PUBL PY 2002 VL 506 BP 43 EP 45 PG 3 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BW17V UT WOS:000181080400009 ER PT S AU Fleck, B Marsden, R AF Fleck, B Marsden, R GP ESA ESA TI Solar orbiter: A mission overview and status update SO SOLAR VARIABILITY: FROM CORE TO OUTER FRONTIERS, VOLS 1 & 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Solar Physics Meeting CY SEP 09-14, 2002 CL PRAGUE, CZECH REPUBLIC SP European Commiss, European Phys Soc, European Space Agcy, Astron Inst Acad Sci, Prvni Energeticka a s DE sun; heliosphere; space plasma physics; UV/EUV; instrumentation AB Approved in October 2000 by ESA's Science Programme Committee as a flexi-mission and reconfirmed in May 2002 as an element in the new ESA science programme "Cosmic Vision", the Solar Orbiter will study the Sun and unexplored regions of the inner heliosphere from a unique orbit that brings the probe to within 45 solar radii of our star, and to solar latitudes as high as 38 degrees. The scientific payload to be carried by the Solar Orbiter will include both remote-sensing instruments and an in situ package. Launch is currently scheduled for 2012. Given the technical challenges associated with this mission, it is essential that key technologies requiring significant development be identified as early as possible. ESA has therefore set up Payload Working Groups whose task it is to address potential problem areas arising as a result of the extreme thermal and radiation environment and to identify necessary technological developments. C1 NASA, Goddard Space Flight Ctr, ESA, Res & Sci Support Dept, Greenbelt, MD 20771 USA. RP Fleck, B (reprint author), NASA, Goddard Space Flight Ctr, ESA, Res & Sci Support Dept, Mail Code 682, Greenbelt, MD 20771 USA. RI Fleck, Bernhard/C-9520-2012 NR 7 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 92-9092-816-6 J9 ESA SP PUBL PY 2002 VL 506 BP 919 EP 922 PG 4 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BW17V UT WOS:000181080400210 ER PT S AU Dimitoglou, G AF Dimitoglou, G GP ESA ESA TI Federation of solar archives: A new approach SO SOLAR VARIABILITY: FROM CORE TO OUTER FRONTIERS, VOLS 1 & 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Solar Physics Meeting CY SEP 09-14, 2002 CL PRAGUE, CZECH REPUBLIC SP European Commiss, European Phys Soc, European Space Agcy, Astron Inst Acad Sci, Prvni Energeticka a s AB The explosion of WWW-based technologies has opened new doors towards creating a single, WWW-based, comprehensive view of archived solar data. The inherit geographic distribution, along with data representation heterogeneity (in standards and tools used), coupled with basic infrastructure constraints (network bandwidth) have hindered the progress of such efforts. Fortunately, the problems of distribution, resource discovery in heterogeneous environments and load balancing to overcome network limitations are areas that have been addressed and resolved in other disciplines (i.e. Computer Science). Borrowing some of these solutions could enable the Solar Physics community to successfully federate existing and new data sets for the benefit of researches now and in the years to come. A suggested architecture is proposed that address most of the issues of federating Solar Physics data archives. C1 NASA, Goddard Space Flight Ctr, ESA, SOHO,EITI, Greenbelt, MD 20771 USA. RP Dimitoglou, G (reprint author), NASA, Goddard Space Flight Ctr, ESA, SOHO,EITI, Code 682-3, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-816-6 J9 ESA SP PUBL PY 2002 VL 506 BP 927 EP 928 PG 2 WC Astronomy & Astrophysics; Instruments & Instrumentation SC Astronomy & Astrophysics; Instruments & Instrumentation GA BW17V UT WOS:000181080400212 ER PT S AU Vekilov, PG Chernov, AA AF Vekilov, PG Chernov, AA BE Ehrenreich, H Spaepen, F TI The physics of protein crystallization SO SOLID STATE PHYSICS: ADVANCES IN RESEARCH AND APPLICATIONS, VOL 57 SE Solid State Physics LA English DT Review ID ATOMIC-FORCE-MICROSCOPY; EGG-WHITE LYSOZYME; MACROMOLECULAR CRYSTAL-GROWTH; LIQUID PHASE-SEPARATION; X-RAY-DIFFRACTION; 101 ADP FACE; PHOTON-CORRELATION SPECTROSCOPY; LIGHT-SCATTERING INVESTIGATIONS; EQUILIBRIUM STEP DYNAMICS; 2ND VIRIAL-COEFFICIENT C1 Univ Houston, Dept Chem Engn, Houston, TX 77546 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Vekilov, PG (reprint author), Univ Houston, Dept Chem Engn, Houston, TX 77546 USA. NR 414 TC 53 Z9 53 U1 1 U2 18 PU ELSEVIER ACADEMIC PRESS INC PI SAN DIEGO PA 525 B STREET, SUITE 1900, SAN DIEGO, CA 92101-4495 USA SN 0081-1947 BN 0-12-607757-6 J9 SOLID STATE PHYS JI Solid State Phys. PY 2002 VL 57 BP 1 EP 147 PG 147 WC Physics, Condensed Matter SC Physics GA BW37U UT WOS:000181788200001 ER PT S AU Jones, HP Harvey, JW Henney, CJ Hill, F Keller, CU AF Jones, HP Harvey, JW Henney, CJ Hill, F Keller, CU BE SawayaLacoste, H TI Data analysis for the solis vector spectromagnetograph SO SOLMAG 2002: PROCEEDINGS OF THE MAGNETIC COUPLING OF THE SOLAR ATMOSPHERE EUROCONFERENCE AND IAU COLLOQUIUM 188 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Euroconference/IAU Colloquium 188 on Magnetic Coupling of the Solar Atmosphere CY JUN 11-15, 2002 CL SANTORINI, GREECE SP Natl Observ Athens, Max Planck Inst Aeron, European Commiss, European Space Agcy, Int Astron Union, ASTRIUM, EFG Eurobank Ergasias, Univ Athens, Hellenic Aerosp Agcy ID MAGNETIC-FIELDS AB The National Solar Observatory's SOLIS Vector Spectromagnetograph, which will produce three or more full-disk maps of the Sun's photospheric vector magnetic field every day for at least one solar magnetic cycle, is in the final stages of assembly. Initial observations including cross-calibration with the current NASA/NSO spectromagnetgraph (SPM), will soon be carried out at a test site in Tucson. This paper discusses data analysis techniques for reducing the raw data, calculation of line-of-sight magnetograms, and both quick-look and high-precision inference of vector fields from Stokes spectral profiles. Existing SPM algorithms, suitably modified to accommodate the cameras, scanning pattern, and polarization calibration optics for the VSM, will be used to "clean" the raw data and to process line-of-sight magetograms. A recent version of the High Altitude Observatory Milne-Eddington (HAO-ME) inversion code [1] will be used for high-precision vector fields. C1 NSO, NASA, Goddard Space Flight Ctr, SW Solar Stn, Tucson, AZ 85726 USA. RP Jones, HP (reprint author), NSO, NASA, Goddard Space Flight Ctr, SW Solar Stn, POB 26732, Tucson, AZ 85726 USA. NR 8 TC 14 Z9 14 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 92-9092-815-8 J9 ESA SP PUBL PY 2002 VL 505 BP 15 EP 18 PG 4 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BW32X UT WOS:000181586100003 ER PT S AU Ruzmaikin, A AF Ruzmaikin, A BE SawayaLacoste, H TI Multi-angle exploration of the sun SO SOLMAG 2002: PROCEEDINGS OF THE MAGNETIC COUPLING OF THE SOLAR ATMOSPHERE EUROCONFERENCE AND IAU COLLOQUIUM 188 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Euroconference/IAU Colloquium 188 on Magnetic Coupling of the Solar Atmosphere CY JUN 11-15, 2002 CL SANTORINI, GREECE SP Natl Observ Athens, Max Planck Inst Aeron, European Commiss, European Space Agcy, Int Astron Union, ASTRIUM, EFG Eurobank Ergasias, Univ Athens, Hellenic Aerosp Agcy ID PARTICLE-ACCELERATION; MAGNETIC-FIELD; EMERGING FLUX; SOLAR-WIND; LONGITUDES; SHOCKS; MODEL; WAVES AB We describe the concept of a proposed new mission, called Multi-Angle Solar Sources Explorer (MASSE), that would observe the Sun from an orbit at 0.72 AU and over all solar longitudes [1]. It would, in coordination with observations taken from Earth's side, investigate the sources of solar activity from their origin deep within the Sun, their emergence onto the photosphere, and their ejection into the Heliosphere. It carries a Doppler-magnetic imager, and in situ energetic particle, solar wind, and magnetic field detectors. convection zone cannot be well investigated with a narrow field of view or bounced waves. An effective way to overcome these limitations is simultaneous observation of the solar surface from multiple points of view i.e. two or three points of view including observations from the position of the Earth. Multiviewing of the Sun uncovers the development of space weather related activity and helps to understand mechanisms of acceleration of energetic particles by coronal mass ejections. Three-dimensional views of the convection zone, where solar activity originates, are reconstructed by correlating MASSE and Earth-side Doppler signals from acoustic wave packets traversing deep solar layers. Magnetic images reveal the evolution of active regions over the entire solar surface and allow the study of emerging fields from deep layers. MASSE particle, plasma, and magnetic field data provide information on the sites and mechanisms of acceleration of hazardous high-energy particles produced by coronal mass ejections. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 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 92-9092-815-8 J9 ESA SP PUBL PY 2002 VL 505 BP 53 EP 56 PG 4 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BW32X UT WOS:000181586100010 ER PT S AU Fleck, B AF Fleck, B BE SawayaLacoste, H TI Prospects of future solar space missions SO SOLMAG 2002: PROCEEDINGS OF THE MAGNETIC COUPLING OF THE SOLAR ATMOSPHERE EUROCONFERENCE AND IAU COLLOQUIUM 188 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Euroconference/IAU Colloquium 188 on Magnetic Coupling of the Solar Atmosphere CY JUN 11-15, 2002 CL SANTORINI, GREECE SP Natl Observ Athens, Max Planck Inst Aeron, European Commiss, European Space Agcy, Int Astron Union, ASTRIUM, EFG Eurobank Ergasias, Univ Athens, Hellenic Aerosp Agcy AB Recent results from solar space missions like Yohkoh, SOHO, TRACE, ACE, and Ulysses have produced stunning results that are invigorating solar research and challenging existing models of the Sun. Future space missions and new ground-based instruments promise to continue this "solar renaissance" in all areas of solar physics. This paper provides an overview of the next generation of solar space missions. The scientific objectives, mission profiles and payload capabilities of Solar-B, STEREO, Picard, SST, SDO, ASCE, Solar Probe, Solar Orbiter, Sentinels, and RAM are summarized. C1 NASA, Goddard Space Flight Ctr, Res & Sci Support Dept, Greenbelt, MD 20771 USA. RP Fleck, B (reprint author), NASA, Goddard Space Flight Ctr, Res & Sci Support Dept, Mail Code 682, Greenbelt, MD 20771 USA. RI Fleck, Bernhard/C-9520-2012 NR 9 TC 1 Z9 1 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 92-9092-815-8 J9 ESA SP PUBL PY 2002 VL 505 BP 311 EP 318 PG 8 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BW32X UT WOS:000181586100056 ER PT S AU Ireland, J Walsh, RW De Moortel, I Moretti, PF AF Ireland, J Walsh, RW De Moortel, I Moretti, PF BE SawayaLacoste, H TI Examination of the photospheric magnetic field underlying longitudinally oscillating coronal loops SO SOLMAG 2002: PROCEEDINGS OF THE MAGNETIC COUPLING OF THE SOLAR ATMOSPHERE EUROCONFERENCE AND IAU COLLOQUIUM 188 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Euroconference/IAU Colloquium 188 on Magnetic Coupling of the Solar Atmosphere CY JUN 11-15, 2002 CL SANTORINI, GREECE SP Natl Observ Athens, Max Planck Inst Aeron, European Commiss, European Space Agcy, Int Astron Union, ASTRIUM, EFG Eurobank Ergasias, Univ Athens, Hellenic Aerosp Agcy DE sun; magnetic field; photosphere; corona ID SUNSPOT TRANSITION REGION; TRANSVERSE OSCILLATIONS; TRACE AB Longitudinally oscillating coronal loops have been seen in TRACE 171 Angstrom data in many different quiescent active regions. The oscillation is thought to be an example of an outwardly propagating slow magneto-acoustic wave. However, the source of these waves is as yet unknown. In the context of SOHO Joint Observing Program 144, we search for a possible photospheric driver to these waves. We examine the photospheric longitudinal magnetic flux underlying an oscillating loop observed between 1200-1300 UT on June 7th 2001. The field was imaged using the Kanzelhohe Magneto-Optical Filter instrument and the SOHO Michelson Doppler Imager (MDI). The dynamics of the photospheric magnetic field underlying these loops is discussed in the context of possible mechanisms causing the observed coronal oscillations. C1 NASA, Goddard Space Flight Ctr, L3Com Analyt Corp, Greenbelt, MD 20771 USA. RP Ireland, J (reprint author), NASA, Goddard Space Flight Ctr, L3Com Analyt Corp, Code 682-3,Bldg 26, Greenbelt, MD 20771 USA. NR 19 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 92-9092-815-8 J9 ESA SP PUBL PY 2002 VL 505 BP 429 EP 432 PG 4 WC Astronomy & Astrophysics; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BW32X UT WOS:000181586100084 ER PT S AU Jordan, S Garcia, A AF Jordan, S Garcia, A BE SawayaLacoste, H TI An evaluation of solar proxies for irradiance variation SO SOLSPA 2001: PROCEEDINGS OF THE SECOND SOLAR CYCLE AND SPACE WEATHER EUROCONFERENCE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 2nd Euroconference on Solar Cycle and Space Weather CY SEP 24-29, 2001 CL VICO EQUENSE, ITALY SP European Commiss, European Space Agcy, Agenzia Spaziale Italiana, Osservatorio Astron Capodimonte, Osservatorio Astrofis Arcetri, Univ Ric Sci, Reg Campania Assessorato, Univ Napoli Federico II, Observ Paris, CNR Ist Fis Spazio Interplanetario, Cantine Grotta Del Sole AB The problem of assessing the effects of solar irradiance variations on Earth's climate has become of increasing importance as evidence accumulates for global warming. Reliable observations of irradiance variation from space are available only for the past two solar cycles. Proxies must be used to estimate the irradiance variation before that time. We report on preliminary results of testing sunspot area as a relatively easily observed proxy against spatial observations of the irradiance variation. We discuss these early results and outline our plans for the remainder of the study. C1 Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jordan, S (reprint author), Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 6 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 92-9092-749-6 J9 ESA SP PUBL PY 2002 VL 477 BP 225 EP 228 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU85T UT WOS:000177209900053 ER PT J AU Parsons, GR Ingram, GW Havard, R AF Parsons, GR Ingram, GW Havard, R TI First record of the goblin shark Mitsukurina owstoni, Jordan (family Mitsukurinidae) in the Gulf of Mexico SO SOUTHEASTERN NATURALIST LA English DT Article ID LAMNIFORMES AB A goblin shark, Mitsukurina owstoni (family Mitsukurinidae), was captured in the northern Gulf of Mexico at 28degrees44.62' N, 88degrees34.13' W on 25 July 2000. The shark was captured by commercial fishers at 919 to 1,099 meters depth after it became entangled in fishing gear. The shark was female, the gut was empty, and no pups were present. Using regression analysis, the length was estimated to be 540 to 617 cm total length and may be the largest specimen collected to date. This capture from the Gulf of Mexico extends the goblin shark's range into the Atlantic waters of North America. C1 Univ Mississippi, Dept Biol, University, MS 38677 USA. NOAA, Natl Marine Fisheries Serv, Pascagoula, MS 39567 USA. Alabama Marine Resources Div, Dauphin Isl, AL 36528 USA. RP Parsons, GR (reprint author), Univ Mississippi, Dept Biol, University, MS 38677 USA. NR 11 TC 4 Z9 8 U1 5 U2 17 PU HUMBOLDT FIELD RESEARCH INST PI STEUBEN PA PO BOX 9, STEUBEN, ME 04680-0009 USA SN 1528-7092 J9 SOUTHEAST NAT JI Southeast. Nat. PY 2002 VL 1 IS 2 BP 189 EP 192 DI 10.1656/1528-7092(2002)001[0189:FROTGS]2.0.CO;2 PG 4 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 626RJ UT WOS:000179886800007 ER PT J AU Carlson, JK Grace, MA Laco, PK AF Carlson, JK Grace, MA Laco, PK TI An observation of juvenile tiger sharks feeding on clapper rails off the southeastern coast of the United States SO SOUTHEASTERN NATURALIST LA English DT Article ID GALEOCERDO-CUVIER AB From September to October 2000, a longline survey conducted aboard the NOAA/National Marine Fisheries Service's research vessel FERREL between Ft. Pierce, FL and Charleston, SC resulted in the capture of 72 juvenile tiger sharks, Galeocerdo cuvier, (mean size = 108 cm total length). Twenty-three were found to have large quantities of feathers, both contour and semiplumes, on the teeth and on the outside of the buccal area. An internal examination of 5 individuals found the remains of clapper rail, Rallus longirostris (100% occurrence). Since clapper rails generally inhabit coastal salt marshes and are not considered to be a migratory species, we could not positively ascertain how juvenile tiger sharks, a species normally found in offshore waters, were able to prey on this bird species. Although we cannot explain the sequence of events that brought these species together, it is possible that the birds were swept offshore by storm winds, there was a "mass exodus" from a marsh habitat due to disturbance, or perhaps a dispersal flight. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Panama City, FL 32408 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Pascagoula, MS 39568 USA. Univ Mississippi, Dept Biol, University, MS 38677 USA. RP Carlson, JK (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 11 TC 2 Z9 3 U1 4 U2 8 PU HUMBOLDT FIELD RESEARCH INST PI STEUBEN PA PO BOX 9, STEUBEN, ME 04680-0009 USA SN 1528-7092 J9 SOUTHEAST NAT JI Southeast. Nat. PY 2002 VL 1 IS 3 BP 307 EP 310 DI 10.1656/1528-7092(2002)001[0307:AOOJTS]2.0.CO;2 PG 4 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 626RP UT WOS:000179887300009 ER PT J AU Bauer, R Krawczyk, R Irwin, D Kruse, H AF Bauer, R Krawczyk, R Irwin, D Kruse, H TI Extending ACTS operations through a university-based consortium SO SPACE COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Ka Band Utilization Conference CY SEP 26-28, 2001 CL GENOA, ITALY AB The Advanced Communications Technology Satellite (ACTS) program was slated for decommissioning in October 2000 as was announced at the 6th Ka-band Utilization Conference in May 2000. Quite a celebration was had at that event too, centering on the decommissioning of this very successful technology program [1]. With plans in place to move the spacecraft to an orbital graveyard and then shut the system down, NASA was challenged to consider the feasibility of extending operations for education and research purposes, provided that an academic organization would be willing to cover operations costs. Continuing operations of the system was determined viable and in the fall of 2000, an announcement was made by NASA to consider extending operations. Plans are now in place to continue the operations of ACTS through a university-based consortium led by Ohio University, Athens, Ohio. Initial plans are for two more years of operations, with options to extend up to a total of four years. This paper will present the change in plans to continue operations of ACTS. A description of the multi-month transition of the spacecraft to its new and final orbital location is provided. With the spacecraft at this new location, an update on its performance is presented as well as estimates of long-term performance. The consortium development will be presented along with its organization, membership and operations plans for using ACTS. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Univ, Stocker Ctr 333, Athens, OH 45701 USA. RP Bauer, R (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 54-6, Cleveland, OH 44135 USA. NR 2 TC 0 Z9 0 U1 2 U2 2 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 2002 VL 18 IS 1-2 SI SI BP 7 EP 12 PG 6 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 618WF UT WOS:000179439700002 ER PT J AU Hsu, E Hung, C desJardins, R Foster, M Gilstrap, R Chao, L Gill, M Tatsumi, H Edelson, B Helm, N MacRae, A Kadowaki, N Yoshimura, N Takahashi, T Gary, P Lang, P Kranacs, K Shopbell, P Walker, G Wellnitz, D Gargione, F AF Hsu, E Hung, C desJardins, R Foster, M Gilstrap, R Chao, L Gill, M Tatsumi, H Edelson, B Helm, N MacRae, A Kadowaki, N Yoshimura, N Takahashi, T Gary, P Lang, P Kranacs, K Shopbell, P Walker, G Wellnitz, D Gargione, F TI Trans-Pacific HDR satellite communications experiment, Phase-2 results summary SO SPACE COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Ka Band Utilization Conference CY SEP 26-28, 2001 CL GENOA, ITALY AB In 1993, a proposal at the Japan-US Science, Technology, and Space Applications Program (JUSTSAP) workshop led to a subsequent series of satellite communications experiments and demonstrations, under the title of Trans-Pacific High Data Rate Satellite Communications Experiments. The first phase of which was a joint collaboration between government and industry teams in the United States and Japan that successfully demonstrated distributed high definition video (HDV) post-production on a global scale using a combination of high data rate satellites and terrestrial fiber optic asynchronous transfer mode (ATM) networks. This was followed by the Phase-2 Internet Protocol (IP) based experiments and demonstrations [4-6] in tele-medicine and distance education, using another combination of two high data rate satellites and terrestrial fiber optic networks. The Visible Human tele-medicine and Remote Astronomy distance education demonstrations and their use of distributed systems technologies afforded an opportunity for people around the world to work together as a virtual team under one roof, using resources thousands of miles away as if they were next to each other. The visible human activity demonstrated global-scale interactive biomedical image segmentation, labeling, classification, and indexing using large images; the remote astronomy activity demonstrated collaborative observation and distance education at multiple locations around the globe and the transparent operations of distributed systems technologies over a combination of broadband satellites and terrestrial networks. The use of Internet Protocol related technologies allowed the general public to be an integral part of the exciting activities, helped to examine issues in constructing a global information infrastructure with broadband satellites, and afforded an opportunity to tap the research results from the (reliable) multicast and distributed systems communities. This paper summarizes the Phase-2 of Trans-Pacific series of experiments and demonstrations by an international team in Canada, Japan, and the United States. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, NASA Res & Educ Network, Incline Village, NV USA. Natl Lib Med, Bethesda, MD USA. Sapporo Med Univ, Sapporo, Hokkaido, Japan. George Washington Univ, Inst Appl Space Res, Washington, DC USA. Independent Adm Inst, Commun Res Lab, Tokyo, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Baltimore, MD 21201 USA. Satellite Syst Consultant, Lawrenceville, NJ USA. RP Hsu, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Ms 300-123, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 1 U2 1 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 2002 VL 18 IS 1-2 SI SI BP 23 EP 30 PG 8 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 618WF UT WOS:000179439700005 ER PT J AU Acosta, R Johnson, S Sands, O Lambert, K AF Acosta, R Johnson, S Sands, O Lambert, K TI Ka-band phased array system characterization SO SPACE COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Ka Band Utilization Conference CY SEP 26-28, 2001 CL GENOA, ITALY AB Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflector-based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2pi phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Analex Corp, Cleveland, OH 44135 USA. RP Acosta, R (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 2002 VL 18 IS 1-2 SI SI BP 39 EP 45 PG 7 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 618WF UT WOS:000179439700007 ER PT J AU Kerczewski, RJ AF Kerczewski, RJ TI Satellite communications for aeronautical applications: recent research and development results SO SPACE COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Ka Band Utilization Conference CY SEP 26-28, 2001 CL GENOA, ITALY AB Communications systems have always been a critical element in aviation. Until recently, nearly all communications between the ground and aircraft have been based on analog voice technology. But the future of global aviation requires a more sophisticated 'information infrastructure' which not only provides more and better communications, but integrates the key information functions (communications, navigation and surveillance) into a modern, network-based infrastructure. Satellite communications will play an increasing role in providing information infrastructure solutions for aviation. Developing and adapting satellite communications technologies for aviation use is now receiving increased attention as the urgency to develop information infrastructure solutions grows. The NASA Glenn Research Center is actively involved in research and development activities for aeronautical satellite communications, with a key emphasis on air traffic management communications needs. This paper describes the recent results and status of NASA Glenn's research program. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kerczewski, RJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 2002 VL 18 IS 1-2 SI SI BP 113 EP 119 PG 7 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 618WF UT WOS:000179439700018 ER PT J AU Williams, WD Ponchak, GE Simons, RN Zaman, AJ Kory, C Wintucky, EG Wilson, JD Scardelletti, MC Lee, RQ Nguyen, HD AF Williams, WD Ponchak, GE Simons, RN Zaman, AJ Kory, C Wintucky, EG Wilson, JD Scardelletti, MC Lee, RQ Nguyen, HD TI RF MEMS and their applications in NASA's space communication systems SO SPACE COMMUNICATIONS LA English DT Article; Proceedings Paper CT 7th Ka Band Utilization Conference CY SEP 26-28, 2001 CL GENOA, ITALY ID SWITCHES C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Analex Corp, NASA Glenn Res Ctr, Cleveland, OH 44135 USA. QSS, Cleveland, OH USA. RP Williams, WD (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 11 TC 1 Z9 1 U1 1 U2 3 PU IOS PRESS PI AMSTERDAM PA NIEUWE HEMWEG 6B, 1013 BG AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 2002 VL 18 IS 1-2 SI SI BP 121 EP 127 PG 7 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 618WF UT WOS:000179439700019 ER PT S AU Jorgensen, K Seitzer, P Smith, R Africano, J Monet, D Stansbery, E Matney, M Harris, H AF Jorgensen, K Seitzer, P Smith, R Africano, J Monet, D Stansbery, E Matney, M Harris, H BE Bendisch, J TI Optical observations of geosynchronous debris SO SPACE DEBRIS 2001 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 34th International Symposium of the International-Academy-of-Astronautics held in Conjunction with 52nd International-Astronautical-Federation CY OCT 01-05, 2001 CL TOULOUSE, FRANCE SP Int Acad Astronaut, Int Astronaut Federat AB An optical survey has been started in an effort to characterize the debris population that could endanger operational geostationary satellites. The survey is designed to cover a wide range in orbital longitude, meanwhile encompassing the smallest debris population size as possible. The majority of the observations are being collected using the University of Michigan's 0.6/0.9-m Schmidt telescope at Cerro Tololo, Chile, which is a wide-field ground-based optical telescope equipped with a Charged Coupled Device (CCD) detector. The justification for such a survey, the designs of the survey observing and reduction strategies, and to what types of debris the survey should be sensitive are included herein. initial results from the first season of observing will be shown. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Jorgensen, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code SX, Houston, TX 77058 USA. 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 0278-4017 BN 0-87703-496-6 J9 SCI TECH PY 2002 VL 105 BP 23 EP 29 PG 7 WC Engineering, Aerospace SC Engineering GA BV41X UT WOS:000178902300003 ER PT S AU Johnson, NL AF Johnson, NL BE Bendisch, J TI Trends and options in the disposal of launch vehicle orbital stages SO SPACE DEBRIS 2001 SE SCIENCE AND TECHNOLOGY SERIES LA English DT Proceedings Paper CT 34th International Symposium of the International-Academy-of-Astronautics held in Conjunction with 52nd International-Astronautical-Federation CY OCT 01-05, 2001 CL TOULOUSE, FRANCE SP Int Acad Astronaut, Int Astronaut Federat AB An increasing number of agencies and organizations around the world provide guidelines for the disposal of launch vehicle stages placed in Earth orbit. The limitation of orbital lifetime following the satellite delivery mission, particularly in low Earth orbit, is viewed as one of the most important space debris mitigation measures. For higher altitude missions, orbital stages may be maneuvered into more rapidly decaying orbits or may be left in longer-term disposal orbits. This paper summarizes the recent disposal practices of all launch vehicle types and evaluates their compliance with existing national standards. Although the owners and operators of some satellite systems, Iridium and Globalstar, have levied orbital stage disposal requirements on launch service providers, in general, insufficient attention and communication is given to this topic. Sun-synchronous and geosynchronous missions may pose some of the most difficult challenges for the responsible disposal of orbital stages. A variety of disposal options are normally available, some of which may even influence the design of the spacecraft to be deployed. Also at issue is whether normal launch vehicle propellant reserves can be relied upon for postmission disposal of orbital stages. C1 NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 0278-4017 BN 0-87703-496-6 J9 SCI TECH PY 2002 VL 105 BP 243 EP 256 PG 14 WC Engineering, Aerospace SC Engineering GA BV41X UT WOS:000178902300019 ER PT S AU Ortiz, GG AF Ortiz, GG BE Bainum, PM JohnsonFreese, J Nakajima, T Uesugi, K TI Sub-microradian pointing for free-space optical communications SO SPACE DEVELOPMENT AND COOPERATION AMONG ALL PACIFIC BASIN COUNTRIES SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 9th International Space Conference of Pacific-Basin-Societies CY NOV 14-16, 2001 CL PASADENA, CA SP Japanese Rocket Soc, Chinese Soc Astronaut, Amer Astronaut Soc ID COMMUNICATIONS DEMONSTRATOR AB NASA/JPL has been developing technologies for a novel and unified approach to point a laser beam from deep space with sub-micro-radian precision for optical communication systems. The approach is based on using high bandwidth inertial sensors to compensate for jitter excursions caused by spacecraft vibrations. This use of high bandwidth inertial sensors enables the implementation of laser communication links anywhere within the solar system (and even beyond). A widely accepted scheme for accomplishing the detection, tracking, and pointing function (required in free-space optical-communications) is to split a fraction of a received uplink beacon signal and direct it onto a focal plane array (FPA) detector. The motion of the focal spot on the FPA is tracked to accurately point the downlink data signal to the Earth receiving station. For deep space links, the historical approach to compensate for spacecraft vibrations and dead-band excursions has been to close a high-bandwidth pointing-control-loop using optical-tracking (> 500 Hz). But, this method required the use of a separate uplink beacon (laser or Earth image). However, studies have shown that using these optical-tracking references become limited in tracking bandwidth in deep space applications, because of the small amount of signal reaching the spacecraft. Our recent analysis and simulations indicate that, by augmenting the current architecture (celestial optical tracking) through the use of high rate inertial sensors (gyros, accelerometers, rate sensors), the tracking and pointing performance will be improved to the sub-micro-radian level. Analogous to an attitude and control subsystem, the spacecraft motion is measured using the gyros, and this measurement is used to correct instrument pointing. Optical updates are then made infrequently to correct for the low frequency inertial sensor drift. Since optical measurements are no longer needed at the rate required to close the pointing compensation loop, such a scheme allows for a significant reduction of the required tracking update rate. Furthermore, this technique enables the use of dimmer stars (and/or a dim uplink laser). Therefore, combined with a low rate, high accuracy optical tracker, these inertial sensors can be successfully used to compensate for jitter, to close the control loop and to point to a receiving station with sub-micro-radian accuracy. This presentation will cover innovative hardware, algorithms, architectures, techniques and recent laboratory results that are applicable to all deep space optical communication links. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ortiz, GG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 161-135, Pasadena, CA 91109 USA. NR 18 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 0-87703-489-3 J9 ADV ASTRONAUT SCI PY 2002 VL 110 BP 195 EP 212 PG 18 WC Engineering, Aerospace SC Engineering GA BU97W UT WOS:000177551800016 ER PT S AU George, K Willingham, V Wu, H Gridley, D Nelson, G Cucinotta, FA AF George, K Willingham, V Wu, H Gridley, D Nelson, G Cucinotta, FA BE Ijiri, K Slenzka, K Kronenberg, A TI Chromosome aberrations in human lymphocytes induced by 250 MeV protons: Effects of dose, dose rate and shielding SO SPACE LIFE SCIENCES: BIOLOGICAL RESEARCH AND SPACE RADIATION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 2/F1 3/F1 3/F2 2 and F2 6 Symposia of COSPAR Scientific Commission F, held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res, NASA ID IN-SITU HYBRIDIZATION; TARGET FRAGMENTATION; X-RAYS; BIODOSIMETRY; PARTICLES; EXCHANGES; MIR-18 AB Although the space radiation environment consists predominantly of energetic protons, astronauts inside a spacecraft are chronically exposed to both primary particles as well as secondary particles that are generated when the primary particles penetrate the spacecraft shielding. Secondary neutrons and secondary charged particles can have an LET value that is greater than the primary protons and, therefore, produce a higher relative biological effectiveness (RBE). Using the accelerator facility at Loma Linda University, we exposed human lymphocytes in vitro to 250 MeV protons with doses ranging from 0 to 60 cGy at three different dose rates: a low dose rate of 7.5 cGy/h, an intermediate dose rate of 30 cGy/h and a high dose rate of 70 cGy/min. The effect of 15 g/cm(2) aluminum shielding on the induction of chromosome aberrations was investigated for each dose rate. After exposure, lymphocytes were incubated in growth medium containing phytohemagglutinin (PHA) and chromosome spreads were collected using a chemical-induced premature chromosome condensation (PCC) technique. Aberrations were analyzed using the fluorescence in situ hybridization (FISH) technique with three different colored chromosome-painting probes. The frequency of reciprocal and complex-type chromosome exchanges were compared in shielded and unshielded samples. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Wyle Labs, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Kelsey Seybold Clin, Houston, TX 77058 USA. Loma Linda Univ, Loma Linda, CA 92354 USA. RP George, K (reprint author), Wyle Labs, 1290 Hercules Dr, Houston, TX 77058 USA. RI Gridley, Daila/P-7711-2015 NR 22 TC 30 Z9 30 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 4 BP 891 EP 899 AR PII S0273-1177(02)00406-4 DI 10.1016/S0273-1177(02)00406-4 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV67M UT WOS:000179730600028 PM 12539753 ER PT S AU Townsend, LW Cucinotta, FA Heilbronn, LH AF Townsend, LW Cucinotta, FA Heilbronn, LH BE Ijiri, K Slenzka, K Kronenberg, A TI Nuclear model calculations and their role in space radiation research SO SPACE LIFE SCIENCES: BIOLOGICAL RESEARCH AND SPACE RADIATION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 2/F1 3/F1 3/F2 2 and F2 6 Symposia of COSPAR Scientific Commission F, held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res, NASA ID PRODUCTION CROSS-SECTIONS; HEAVY-ION FRAGMENTATION; ABSORPTION AB Proper assessments of spacecraft shielding requirements and concomitant estimates of risk to spacecraft crews from energetic space radiation requires accurate, quantitative methods of characterizing the compositional changes in these radiation fields as they pass through thick absorbers. These quantitative methods are also needed for characterizing accelerator beams used in space radiobiology studies. Because of the impracticality/impossibility of measuring these altered radiation fields inside critical internal body organs of biological test specimens and humans, computational methods rather than direct measurements must be used. Since composition changes in the fields arise from nuclear interaction processes (elastic, inelastic and breakup), knowledge of the appropriate cross sections and spectra must be available. Experiments alone cannot provide the necessary cross section and secondary particle (neutron and charged particle) spectral data because of the large number of nuclear species and wide range of energies involved in space radiation research. Hence, nuclear models are needed. In this paper current methods of predicting total and absorption cross sections and secondary particle (neutrons and ions) yields and spectra for space radiation protection analyses are reviewed. Model shortcomings are discussed and future needs presented. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Townsend, LW (reprint author), Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA. RI Heilbronn, Lawrence/J-6998-2013 OI Heilbronn, Lawrence/0000-0002-8226-1057 NR 30 TC 8 Z9 8 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 4 BP 907 EP 916 AR PII S0273-1177(02)00405-2 DI 10.1016/S0273-1177(02)00405-2 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV67M UT WOS:000179730600030 PM 12539757 ER PT S AU Zapp, N Cucinotta, F Atwell, W AF Zapp, N Cucinotta, F Atwell, W BE Ijiri, K Slenzka, K Kronenberg, A TI A comparison of quality factors and weighting factors for characterizing astronaut radiation exposures SO SPACE LIFE SCIENCES: BIOLOGICAL RESEARCH AND SPACE RADIATION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 2/F1 3/F1 3/F2 2 and F2 6 Symposia of COSPAR Scientific Commission F, held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res, NASA AB Radiation exposures are typically characterized by two quantities. The first is the absorbed dose, or the energy deposited per unit mass for specific types of radiation passing through specified materials. The same amount of energy deposited in material by two different types of radiation, however, can result in two different levels of risk. Because of this, for the purpose of radiation protection operations, absorbed dose is modified by a second factor intended to normalize the risk associated with a given exposure. We present here an inter-comparison of methods for this modification. First is the radiation quality factor (Q), as defined by ICRP publication 60. This quantity is related functionally to the unrestricted linear energy transfer (LET) of a given radiation, and is multiplied by the absorbed dose to derive the dose equivalent (H). The second method for modifying absorbed dose is the radiation weighting factor, also given in ICRP-60, or as modified in NCRP report 115. To implement the weighting factor, the absorbed dose resulting from incidence of a particular radiation is multiplied by a factor assigned to that type of radiation, giving the equivalent dose. We compare calculations done based on identical fields of radiation representative of that encountered by the MIR space station, applying each of these two methods. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Wyle Labs, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Boeing N Amer, Houston, TX 77058 USA. RP Zapp, N (reprint author), Wyle Labs, 1200 Hercules Dr,Ste 120, Houston, TX 77058 USA. NR 8 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 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 4 BP 965 EP 974 AR PII S0273-1177(02)00161-8 DI 10.1016/S0273-1177(02)00161-8 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV67M UT WOS:000179730600036 PM 12539766 ER PT S AU Zapp, EN Townsend, LW Cucinotta, FA AF Zapp, EN Townsend, LW Cucinotta, FA BE Ijiri, K Slenzka, K Kronenberg, A TI Solar particle event organ doses and dose equivalents for interplanetary crews: Variations due to body size SO SPACE LIFE SCIENCES: BIOLOGICAL RESEARCH AND SPACE RADIATION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F1 2/F1 3/F1 3/F2 2 and F2 6 Symposia of COSPAR Scientific Commission F, held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res, NASA AB Proper assessments of spacecraft shielding requirements and concomitant estimates of risk to critical body organs of spacecraft crews from energetic space radiation require accurate, quantitative methods of characterizing the compositional changes in these radiation fields as they pass through the spacecraft and overlying tissue. When estimating astronaut radiation organ doses and dose equivalents it is customary to use the Computerized Anatomical Man (CAM) model of human geometry to account for body self-shielding. Usually, the distribution for the 50th percentile man (175cm height; 70kg mass) is used. Most male members of the U. S. astronaut corps are taller and nearly all have heights that deviate from the 175cm mean. In this work, estimates of critical organ doses and dose equivalents for interplanetary crews exposed to an event similar to the October 1989 solar particle event are presented for male body sizes that vary from the 5th to the 95th percentiles. Overall the results suggest that calculations of organ dose and dose equivalent may vary by as much as similar to15% as body size is varied from the 5th to the 95th percentile in the population used to derive the CAM model data. (C) 2002 Published by Elsevier Science Ltd on behalf of COSPAR. C1 Wyle Labs, Houston, TX 77058 USA. Univ Tennessee, Dept Nucl Engn, Knoxville, TN 37996 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Zapp, EN (reprint author), Wyle Labs, Houston, TX 77058 USA. NR 7 TC 7 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 4 BP 975 EP 979 AR PII S0273-1177(02)00166-7 DI 10.1016/S0273-1177(02)00166-7 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BV67M UT WOS:000179730600037 PM 12539772 ER PT S AU Charnley, SB Rodgers, SD Kuan, YJ Huang, HC AF Charnley, SB Rodgers, SD Kuan, YJ Huang, HC BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Biomolecules in the interstellar medium and in comets SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy ID O1 HALE-BOPP; STAR-FORMING REGIONS; POLYCYCLIC AROMATIC-HYDROCARBONS; HOT MOLECULAR CORES; DUST CLOUD TMC-1; ORGANIC-MOLECULES; CHEMICAL DIFFERENTIATION; ABUNDANCE RATIO; COMPACT RIDGE; EARLY EARTH AB We review recent studies of organic molecule formation in dense molecular clouds and in comets. We summarise the known organic. inventories of molecular clouds and recent comets, particularly Hale-Bopp. The principal chemical formation pathways involving gas phase reactions, as well as formation by catalytic reactions on grain surfaces or through dust fragmentation, are identified for both dense clouds and cometary comae. The processes leading to organic molecules with known biological function, carbon chains, deuterium fractionation, HNC and S-bearing compounds are described. Observational searches for new interstellar organics are outlined and the connection between observed interstellar organics and those detected in comets Hale-Bopp and Hyakutake are discussed. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Natl Taiwan Normal Univ, Taipei, Taiwan. Acad Sinica, Inst Astron & Astrophys, Taipei, Taiwan. RP NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Charnley, Steven/C-9538-2012 NR 96 TC 25 Z9 25 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2002 VL 30 IS 6 BP 1419 EP 1431 AR PII S0273-1177(02)00499-4 DI 10.1016/S0273-1177(02)00499-4 PG 13 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000004 ER PT S AU Kress, ME Desch, SJ Dateo, CE Benedix, G AF Kress, ME Desch, SJ Dateo, CE Benedix, G BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Shock processing of interstellar nitrogen compounds in the solar nebula SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy ID CHONDRULE FORMATION; WAVE MODEL; DISKS AB Some organic material in chondrites (primitive meteorites) exhibits a very low N-14/N-15, suggesting that the compounds that carry this heavy nitrogen signature formed in the interstellar medium. Other organic components of the same chondrites show a more solar isotopic signature, suggesting they derive from an isotopically solar reservoir of nitrogen such as N-2 or NH3 in the solar nebula. In this work, we model the chemistry of the shocks that have been hypothesized as the mechanism to melt chondrules. We find that such shocks (approximate to 8 km/s) do not produce significant amounts of HCN and CN if all nitrogen is initially locked in N-2 and all carbon is locked in CO. Only when NH3 or CH4 (or both) were present in the initial pre-shock nebula gas do CN and HCN form. We also find that C2H2 (acetylene) and C2H form in low abundances if the carbon is all locked in CO in the pre-shock gas. The presence of CH4 facilitates the formation of acetylene and related compounds. In the absence of CH4 or NH3, only negligible amounts of species containing CdropC or CdropN bonds form. Acetylene and cyanide-related compound's may be precursors to the organics that condensed into meteorites about 4.5 billion years ago. We find that CN bonds largely survive these shocks; thus, the very low interstellar N-14/N-15 signature can be preserved if the N-15 is carried by CdropN-bearing interstellar compounds. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Washington, Astrobiol Program, Seattle, WA 98195 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. RP Univ Washington, Astrobiol Program, Seattle, WA 98195 USA. OI Benedix, Gretchen/0000-0003-0990-8878 NR 15 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2002 VL 30 IS 6 BP 1473 EP 1480 AR PII S0273-1177(02)00505-7 DI 10.1016/S0273-1177(02)00505-7 PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000011 ER PT S AU Bernstein, MP Dworkin, JP Sandford, SA Allamandola, LJ AF Bernstein, MP Dworkin, JP Sandford, SA Allamandola, LJ BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Ultraviolet irradiation of the polycyclic aromatic hydrocarbon (PAH) naphthalene in H2O. Implications for meteorites and biogenesis SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy ID INTERPLANETARY DUST PARTICLES; LASER MASS-SPECTROMETRY; EARLY SOLAR-SYSTEM; ORGANIC-COMPOUNDS; ASTROPHYSICAL IMPLICATIONS; CARBONACEOUS CHONDRITES; MURCHISON METEORITE; INFRARED-EMISSION; UV-RADIATION; INTERSTELLAR AB The polycyclic aromatic hydrocarbon (PAH) naphthalene was exposed to ultraviolet radiation in H2O ice under astrophysical conditions, and the products were analyzed using high performance liquid chromatography. As we found in our earlier studies on the photoprocessing of coronene in H2O ice, aromatic alcohols and ketones (quinones) were formed. The regiochemistry reported here leads to specific predictions of the relative abundances of oxidized naphthalenes that should exist in meteorites. Since oxidized PAHs are present in meteorites and interplanetary dust particles, and ubiquitous in and fundamental to biochemistry, the delivery of such extraterrestrial molecules to the early Earth may have played a role in the origin and evolution of life. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 SETI Inst, Ctr Study Life Universe, Mountain View, CA 94043 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP SETI Inst, Ctr Study Life Universe, 2035 Landings Dr, Mountain View, CA 94043 USA. RI Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 44 TC 5 Z9 5 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2002 VL 30 IS 6 BP 1501 EP 1508 AR PII S0273-1177(02)00501-X DI 10.1016/S0273-1177(02)00501-X PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000015 ER PT S AU Pohorille, A AF Pohorille, A BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI From organic molecules in space to the origins of life and back SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH-SERIES LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy ID POLYCYCLIC AROMATIC-HYDROCARBONS; INFLUENZA-A VIRUS; WATER INTERFACES; ION SELECTIVITY; LIPID-BILAYERS; NUCLEIC-ACID; RNA WORLD; PEPTIDE; MEMBRANE; DYNAMICS AB Delivery of organic molecules much simpler than building blocks of biological structures may have been sufficient to initiate the process of chemical evolution leading to the first forms of life. By defining the simplest protocellular systems, it is possible to deduce what organic molecules were likely to be necessary for this process. Some of these molecules were building blocks of protocellular structures which self-assembed from amphiphilic compounds into vesicles and other structures, such as micelles and multilayers. There must also have been relatively simple mechanisms by which amino acids or their precursors were incorporated into simple peptides. At some point this process became compartmented in vesicles, which would require the emergence of cellular transport and metabolism. Energy required for these processes may have been provided by the coupling of the transmembrane proton gradient to the synthesis of high energy compounds, such as thioesters, or by carbon disproportionation reactions, starting with sugars. If these conjectures are correct, it follows that the first forms of life emerged as self-contained molecular systems, rather than as macromolecules that somehow incorporated the basic properties associated with the living state. (C) 2002 Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. NR 53 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND SN 0273-1177 J9 ADV SPACE RES-SERIES PY 2002 VL 30 IS 6 BP 1509 EP 1520 AR PII S0273-1177(02)00509-4 DI 10.1016/S0273-1177(02)00509-4 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000016 ER PT S AU Rummel, JD Stabekis, PD DeVincenzi, DL Barengoltz, JB AF Rummel, JD Stabekis, PD DeVincenzi, DL Barengoltz, JB BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Cospar's planetary protection policy: A consolidated draft SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy AB One of the duties of COSPAR's Panel on Planetary Protection is the development, maintenance, and promulgation of a planetary protection policy. Historically, COSPAR's policy has been maintained in a series of published papers and related Council resolutions, but a consolidated version of the COSPAR policy has not been available. This presentation consists of a draft version of the COSPAR policy as it currently stands, now placed into a single document. This document will form the basis from which it is anticipated that an updated policy will be crafted, and which, if accepted by the Panel, Bureau and Council, will form the basis for future policy deliberations and refinements. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Headquarters, Off Space Sci, Washington, DC 20546 USA. Windermere Grp, Washington, DC 20024 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Rummel, JD (reprint author), NASA, Headquarters, Off Space Sci, Washington, DC 20546 USA. NR 7 TC 15 Z9 15 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 6 BP 1567 EP 1571 AR PII S0273-1177(02)00479-9 DI 10.1016/S0273-1177(02)00479-9 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000022 ER PT S AU Rummel, JD AF Rummel, JD BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Seeking an international consensus in planetary protection: Cospar's planetary protection panel SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy AB Solar system exploration as an international enterprise has entered a new era of activity and multinational cooperation. A number of the currently envisaged missions are targeted to bodies (e.g., Mars, Europa) that have significant interest with respect to the origin of life and chemical evolution, and the potential for biological studies. COSPAR has an important role as the standard-setting international organization in the area of planetary protection-a required reference for international missions to such bodies. Recently, COSPAR has formed a Panel on Planetary Protection that is concerned with the development, maintenance, and promulgation of planetary protection knowledge, policy, and plans to prevent the harmful effects of biological contamination-and through symposia, workshops, and topical meetings at COSPAR Assemblies to provide an international forum for exchange of information in this area. Through COSPAR the Panel will inform the international community, e.g., the Committee on the Peaceful Uses of Outer Space (COPUOS) of the United Nations, as well as various other bilateral and multilateral organizations. This Panel will work to ensure that its deliberations are based on the best current knowledge of the nature of the extraterrestrial bodies involved and to appreciate the potential biological implications of that knowledge. The nature of the deliberations of the body should serve both science and policy development requirements. Example missions for which a consensus agreement on requirements will be sought include Mars sample return missions, Europa Orbiter, and missions to other small bodies of the solar system (MUSES-C and Stardust). Mission planning and implementation efforts need a scientifically appropriate standard, developed as a consensus within the Panel, on which to base their efforts. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Headquarters, Off Space Sci, Washington, DC 20546 USA. RP Rummel, JD (reprint author), NASA, Headquarters, Off Space Sci, Washington, DC 20546 USA. NR 5 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 6 BP 1573 EP 1575 AR PII S0273-1177(02)00476-3 DI 10.1016/S0273-1177(02)00476-3 PG 3 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000023 ER PT S AU McKay, CP AF McKay, CP BE Bernstein, MP Rettberg, P Mancinelli, RL Race, MS TI Planetary protection for a Europa surface sample return: The ice clipper mission SO SPACE LIFE SCIENCES: EXTRATERRESTRIAL ORGANIC CHEMISTRY, UV RADIATION ON BIOLOGICAL EVOLUTION, AND PLANETARY PROTECTION SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT F3 4(1)-B0 8, F3 1 and F3 5-PPP1 Symposia of COSPAR Scientific Commission F held at the 33rd COSPAR Scientific Assembly CY JUN, 2000 CL WARSAW, POLAND SP Comm Space Res, Agenzia Spaziale Italiana, CNES, Deutsch Zentrum Luft & Raumfahrt eV, European Space Agcy ID DEINOCOCCUS-RADIODURANS; GALILEAN SATELLITES; ROCKS AB The surface of Europa may hold biochemical evidence of life in the ocean below. Plans for the analysis and return of samples containing organics from the surface of Europa are well developed; for example, the Ice Clipper Mission. Planetary protection issues must be considered in planning for a returned sample from Europa. Previous studies for sample return from Mars and the return of comet dust by the Stardust mission provide a basis for comparison for a Europa sample return mission. The extreme radiation environment on the surface of Europa would kill even the most radiation resistant microorganism present to depths of many tens of meters in the ice. The Ice Clipper mission would impact sample the upper 1.2 to 3.4 in of the ice depending on the surface hardness. At these depths the radiation dose is expected to be 500 and 40 rads/year, respectively. These dose rates would kill dormant cells in less than 36,000 and 450,000 years even for the most radiation resistant strains. It is therefore likely that a Europa sample return mission such as Ice Clipper can be treated using the Stardust mission as a model for planetary protection, that is, the returned material can be assumed to pose no biological risk. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 14 TC 5 Z9 5 U1 2 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 30 IS 6 BP 1601 EP 1605 AR PII S0273-1177(02)00480-5 DI 10.1016/S0273-1177(02)00480-5 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Immunology; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Immunology; Meteorology & Atmospheric Sciences GA BV68R UT WOS:000179771000027 ER PT J AU Matson, DL Spilker, LJ Lebreton, JP AF Matson, DL Spilker, LJ Lebreton, JP TI The Cassini/Huygens mission to the Saturnian system SO SPACE SCIENCE REVIEWS LA English DT Review ID RADIATION; VENUS AB The international Cassini/Huygens mission consists of the Cassini Saturn Orbiter spacecraft and the Huygens Titan Probe that is targeted for entry into the atmosphere of Saturn's largest moon, Titan. From launch on October 15, 1997 to arrival at Saturn in July 2004, Cassini/Huygens will travel over three billion kilometers. Once in orbit about Saturn, Huygens is released from the orbiter and enters Titan's atmosphere. The Probe descends by parachute and measures the properties of the atmosphere. If the landing is gentle, the properties of the surface will be measured too. Then the orbiter commences a four-year tour of the Saturnian system with 45 flybys of Titan and multiple encounters with the icy moons. The rings, the magnetosphere and Saturn itself are all studied as well as the interactions among them. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European Space Agcy, ESTEC, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. RP Matson, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 56 Z9 58 U1 1 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 1 EP 58 DI 10.1023/A:1023609211620 PG 58 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100001 ER PT J AU Lebreton, JP Matson, DL AF Lebreton, JP Matson, DL TI The Huygens Probe: Science, payload and mission overview SO SPACE SCIENCE REVIEWS LA English DT Review ID CHROMATOGRAPH MASS-SPECTROMETER; DOPPLER WIND EXPERIMENT; TITANS ATMOSPHERE; ADAPTIVE OPTICS; ABOARD HUYGENS; SYSTEM-DESIGN; MODELS; DESCENT; SURFACE; CASSINI/HUYGENS AB Huygens is an entry probe designed to descend under parachute through the atmosphere of Titan, Saturn's largest moon, down to the surface. The main Huygens science mission phase occurs during the 2-2(1/2) hours parachute descent. Measurements will also be conducted during the 3 min entry and possibly up to about one hour on the surface if Huygens survives the landing impact. The Probe's payload comprises six instruments. The Huygens Probe is provided by the European Space Agency (ESA) for the joint NASA/ESA Cassini/Huygens mission to Saturn and Titan. This paper provides an overview of the Huygens mission and a concise description of the payload as an introduction to the papers which describe the Huygens investigations in this volume. C1 European Space Agcy, ESTEC, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lebreton, JP (reprint author), European Space Agcy, ESTEC, Res & Sci Support Dept, POB 299, NL-2200 AG Noordwijk, Netherlands. EM Jean-Pierre.Lebreton@rssd.essa.int NR 54 TC 45 Z9 45 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-4 BP 59 EP 100 DI 10.1023/A:1023657127549 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100002 ER PT J AU Wolf, AA AF Wolf, AA TI Touring the Saturnian system SO SPACE SCIENCE REVIEWS LA English DT Review ID DESIGN AB The Cassini mission to Saturn employs a Saturn orbiter and a Titan probe to conduct an intensive investigation of the Saturnian system. The orbiter flies a series of orbits, incorporating flybys of the Saturnian satellites, called the 'satellite tour.' During the tour, the gravitational fields of the satellites (mainly Titan) are used to modify and control the orbit, targeting from one satellite flyby to the next. The tour trajectory must also be designed to maximize opportunities for a diverse set of science observations, subject to mission-imposed constraints. Tour design studies have been conducted for Cassini over a period of several years to identify trades and strategies for achieving these sometimes conflicting goals. Concepts, strategies, and techniques previously developed for the Galileo mission to Jupiter have been modified, and new ones have been developed, to meet the requirements of the Cassini mission. A sample tour is presented illustrating the application of tour design strategies developed for Cassini. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wolf, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 12 Z9 12 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 101 EP 128 DI 10.1023/A:1023692724823 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100003 ER PT J AU Henry, CA AF Henry, CA TI An introduction to the design of the Cassini spacecraft SO SPACE SCIENCE REVIEWS LA English DT Review AB In October of 1997 NASA launched its largest interplanetary spacecraft to date. The Cassini spacecraft will arrive at Saturn in July of 2004 and begin a four year tour of that planetary system. After the spacecraft arrives it will separate into an orbiter and a probe. The Huygens Probe, developed by the European Space Agency, will follow a ballistic trajectory into the atmosphere of the moon Titan. The orbiter will relay signals received from the probe back to Earth and then begin the tour. This article provides an introduction to the design of the Cassini spacecraft. The major engineering functions of mechanical configuration, power generation and distribution, telecommunications, information system, pointing and course correction, and some other miscellaneous design features are discussed. A description of the engineering elements of the Huygens Probe is also provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Henry, CA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 2 Z9 2 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 129 EP 153 DI 10.1023/A:1023696808894 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100004 ER PT J AU Cuzzi, JN Colwell, JE Esposito, LW Porco, CC Murray, CD Nicholson, PD Spilker, LJ Marouf, EA French, RC Rappaport, N Muhleman, D AF Cuzzi, JN Colwell, JE Esposito, LW Porco, CC Murray, CD Nicholson, PD Spilker, LJ Marouf, EA French, RC Rappaport, N Muhleman, D TI Saturn's rings: Pre-Cassini status and mission goals SO SPACE SCIENCE REVIEWS LA English DT Review ID PARTICLE EROSION MECHANISMS; DENSE PLANETARY RINGS; JOVIAN DUST STREAMS; SATELLITE LINDBLAD RESONANCES; VOYAGER-1 RADIO OCCULTATION; NEAR-INFRARED OBSERVATIONS; HUBBLE-SPACE-TELESCOPE; OUTER-B-RING; F-RING; BALLISTIC TRANSPORT AB Theoretical and observational progress in studies of Saturn's ring system since the mid-1980s is reviewed, focussing on advances in configuration and dynamics, composition and size distribution, dust and meteoroids, interactions of the rings with the planet and the magnetosphere, and relationships between the rings and various satellites. The Cassini instrument suite of greatest relevance to ring studies is also summarized, emphasizing how the individual instruments might work together to solve outstanding problems. The Cassini tour is described from the standpoint of ring studies, and major ring science goals are summarized. C1 NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, LASP, Boulder, CO 80309 USA. SW Res Inst, Boulder, CO USA. Queen Mary Univ London, Dept Math, London E1 4NS, England. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Jet Propuls Lab, Pasadena, CA USA. San Jose State Univ, Dept Elect Engn, San Jose, CA 95192 USA. Wellesley Coll, Astromy Dept, Wellesley, MA 02181 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Cuzzi, JN (reprint author), NASA, Div Space Sci, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 244 TC 20 Z9 20 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-4 BP 209 EP 251 DI 10.1023/A:1023653026641 PG 43 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100007 ER PT J AU Blanc, M Bolton, S Bradley, J Burton, M Cravens, TE Dandouras, I Dougherty, MK Festou, MC Feynman, J Johnson, RE Gombosi, TG Kurth, WS Liewer, PC Mauk, BH Maurice, S Mitchell, D Neubauer, FM Richardson, JD Shemansky, DE Sittler, EC Tsurutani, BT Zarka, P Esposito, LW Grun, E Gurnett, DA Kliore, AJ Krimigis, SM Southwood, D Waite, JH Young, DT AF Blanc, M Bolton, S Bradley, J Burton, M Cravens, TE Dandouras, I Dougherty, MK Festou, MC Feynman, J Johnson, RE Gombosi, TG Kurth, WS Liewer, PC Mauk, BH Maurice, S Mitchell, D Neubauer, FM Richardson, JD Shemansky, DE Sittler, EC Tsurutani, BT Zarka, P Esposito, LW Grun, E Gurnett, DA Kliore, AJ Krimigis, SM Southwood, D Waite, JH Young, DT TI Magnetospheric and plasma science with Cassini-Huygens SO SPACE SCIENCE REVIEWS LA English DT Review ID EXTREME ULTRAVIOLET OBSERVATIONS; SATURNS KILOMETRIC RADIATION; MAGNETIC-FIELD; INNER MAGNETOSPHERE; TITANS IONOSPHERE; MHD MODEL; JOVIAN MAGNETOSPHERE; RADIO OCCULTATION; WAVE OBSERVATIONS; THERMAL PLASMA AB Magnetospheric and plasma science studies at Saturn offer a unique opportunity to explore in-depth two types of magnetospheres. These are an 'induced' magnetosphere generated by the interaction of Titan with the surrounding plasma flow and Saturn's 'intrinsic' magnetosphere, the magnetic cavity Saturn's planetary magnetic field creates inside the solar wind flow. These two objects will be explored using the most advanced and diverse package of instruments for the analysis of plasmas, energetic particles and fields ever flown to a planet. These instruments will make it possible to address and solve a series of key scientific questions concerning the interaction of these two magnetospheres with their environment. The flow of magnetospheric plasma around the obstacle, caused by Titan's atmosphere/ionosphere, produces an elongated cavity and wake, which we call an 'induced magnetosphere'. The Mach number characteristics of this interaction make it unique in the solar system. We first describe Titan's ionosphere, which is the obstacle to the external plasma flow. We then study Titan's induced magnetosphere, its structure, dynamics and variability, and discuss the possible existence of a small intrinsic magnetic field of Titan. Saturn's magnetosphere, which is dynamically and chemically coupled to all other components of Saturn's environment in addition to Titan, is then described. We start with a summary of the morphology of magnetospheric plasma and fields. Then we discuss what we know of the magnetospheric interactions in each region. Beginning with the innermost regions and moving outwards, we first describe the region of the main rings and their connection to the low-latitude ionosphere. Next the icy satellites, which develop specific magnetospheric interactions, are imbedded in a relatively dense neutral gas cloud which also overlaps the spatial extent of the diffuse E ring. This region constitutes a very interesting case of direct and mutual coupling between dust, neutral gas and plasma populations. Beyond about twelve Saturn radii is the outer magnetosphere, where the dynamics is dominated by its coupling with the solar wind and a large hydrogen torus. It is a region of intense coupling between the magnetosphere and Saturn's upper atmosphere, and the source of Saturn's auroral emissions, including the kilometric radiation. For each of these regions we identify the key scientific questions and propose an investigation strategy to address them. Finally, we show how the unique characteristics of the CASSINI spacecraft, instruments and mission profile make it possible to address, and hopefully solve, many of these questions. While the CASSINI orbital tour gives access to most, if not all, of the regions that need to be explored, the unique capabilities of the MAPS instrument suite make it possible to define an efficient strategy in which in situ measurements and remote sensing observations complement each other. Saturn's magnetosphere will be extensively studied from the microphysical to the global scale over the four years of the mission. All phases present in this unique environment-extended solid surfaces, dust and gas clouds, plasma and energetic particles-are coupled in an intricate way, very much as they are in planetary formation environments. This is one of the most interesting aspects of Magnetospheric and Plasma Science studies at Saturn. It provides us with a unique opportunity to conduct an in situ investigation of a dynamical system that is in some ways analogous to the dusty plasma environments in which planetary systems form. C1 Observ Midi Pyrenees, F-31400 Toulouse, France. Jet Propuls Lab, Pasadena, CA USA. Univ Kansas, Lawrence, KS 66045 USA. CESR, Toulouse, France. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. Univ Virginia, Charlottesville, VA USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Univ Cologne, Inst Geophys & Meteorol, D-5000 Cologne, Germany. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ So Calif, Dept Aerosp Engn, Los Angeles, CA 90089 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Paris, DESPA, Meudon, France. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. SW Res Inst, San Antonio, TX USA. RP Blanc, M (reprint author), Observ Midi Pyrenees, F-31400 Toulouse, France. RI Gombosi, Tamas/G-4238-2011; Mauk, Barry/E-8420-2017; OI Gombosi, Tamas/0000-0001-9360-4951; Mauk, Barry/0000-0001-9789-3797; Dandouras, Iannis/0000-0002-7121-1118; Kurth, William/0000-0002-5471-6202 NR 150 TC 37 Z9 37 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 253 EP 346 DI 10.1023/A:1023605110711 PG 94 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100008 ER PT J AU Fulchignoni, M Ferri, F Angrilli, F Bar-Nun, A Barucci, MA Bianchini, G Borucki, W Coradini, M Coustenis, A Falkner, P Flamini, E Grard, R Hamelin, M Harri, AM Leppelmeier, GW Lopez-Moreno, JJ McDonnell, JAM McKay, CP Neubauer, FH Pedersen, A Picardi, G Pirronello, V Rodrigo, R Schwingenschuh, K Seiff, A Svedhem, H Vanzani, V Zarnecki, J AF Fulchignoni, M Ferri, F Angrilli, F Bar-Nun, A Barucci, MA Bianchini, G Borucki, W Coradini, M Coustenis, A Falkner, P Flamini, E Grard, R Hamelin, M Harri, AM Leppelmeier, GW Lopez-Moreno, JJ McDonnell, JAM McKay, CP Neubauer, FH Pedersen, A Picardi, G Pirronello, V Rodrigo, R Schwingenschuh, K Seiff, A Svedhem, H Vanzani, V Zarnecki, J TI The characterisation of Titan's atmospheric physical properties by the Huygens Atmospheric Structure Instrument (HASI) SO SPACE SCIENCE REVIEWS LA English DT Review ID VOYAGER INFRARED OBSERVATIONS; PRESSURE PROFILE INSTRUMENT; LIGHTNING ACTIVITY; THERMAL STRUCTURE; TEMPERATURE; SURFACE; MARS; TROPOSPHERE; OCCULTATION; BALLOON AB The Huygens Atmospheric Structure Instrument (HASI) is a multi-sensor package which has been designed to measure the physical quantities characterising the atmosphere of Titan during the Huygens probe descent on Titan and at the surface. HASI sensors are devoted to the study of Titan's atmospheric structure and electric properties, and to provide information on its surface, whether solid or liquid. C1 Observ Paris, Dept Rech Spatiale, DESPA, Meudon, France. Univ Padua, CISAS, Ctr Studies & Activ Space G Colombo, I-35100 Padua, Italy. Univ Paris 07, F-75221 Paris 05, France. Tel Aviv Univ, Dept Geophys & Planetary Sci, IL-69978 Tel Aviv, Israel. NASA, AMES, Moffett Field, CA 94035 USA. ESA, Sci Directorate, F-75738 Paris 15, France. ESTEC, Solar Syst Div, Noordwijk, Netherlands. Agenzia Spaziale Italiana, Rome, Italy. LPCE, Orleans, France. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. CSIC, IAA, Granada, Spain. Univ Kent, Canterbury, Kent, England. Univ Cologne, D-5000 Cologne 41, Germany. Univ Oslo, N-0316 Oslo, Norway. Univ Roma La Sapienza, Rome, Italy. Osserv Astrofis Catania, I-95125 Catania, Italy. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. San Jose State Univ Fdn, Dept Meteorol, San Jose, CA 95192 USA. RP Fulchignoni, M (reprint author), Observ Paris, Dept Rech Spatiale, DESPA, Meudon, France. RI Lopez-Moreno, Jose Juan/C-7976-2011; Harri, Ari-Matti/C-7142-2012; OI Harri, Ari-Matti/0000-0001-8541-2802; Lopez-Moreno, Jose Juan/0000-0002-7946-2624 NR 57 TC 43 Z9 43 U1 1 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 395 EP 431 DI 10.1023/A:1023688607077 PG 37 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100011 ER PT J AU Israel, G Cabane, M Brun, JF Niemann, H Way, S Riedler, W Steller, M Raulin, F Coscia, D AF Israel, G Cabane, M Brun, JF Niemann, H Way, S Riedler, W Steller, M Raulin, F Coscia, D TI Huygens Probe aerosol collector pyrolyser experiment SO SPACE SCIENCE REVIEWS LA English DT Review ID TITANS ATMOSPHERE AB ACP's main objective is the chemical analysis of the aerosols in Titan's atmosphere. For this purpose, it will sample the aerosols during descent and prepare the collected matter (by evaporation, pyrolysis and gas products transfer) for analysis by the Huygens Gas Chromatograph Mass Spectrometer (GCMS). A sampling system is required for sampling the aerosols in the 135-32 km and 22-17 km altitude regions of Titan's atmosphere. A pump unit is used to force the gas flow through a filter. In its sampling position, the filter front face extends a few mm beyond the inlet tube. The oven is a pyrolysis furnace where a heating element can heat the filter and hence the sampled aerosols to 250degreesC or 600degreesC. The oven contains the filter, which has a thimble-like shape (height 28 mm). For transferring effluent gas and pyrolysis products to GCMS, the carrier gas is a labeled nitrogen N-15(2), to avoid unwanted secondary reactions with Titan's atmospheric nitrogen. Aeraulic tests under cold temperature conditions were conducted by using a cold gas test system developed by ONERA. The objective of the test was to demonstrate the functional ability of the instrument during the descent of the probe and to understand its thermal behavior, that is to test the performance of all its components, pump unit and mechanisms. In order to validate ACP's scientific performance, pyrolysis tests were conducted at LISA on solid phase material synthesized from experimental simulation. The chromatogram obtained by GCMS analysis shows many organic compounds. Some GC peaks appear clearly from the total mass spectra, with specific ions well identified thanks to the very high sensitivity of the mass spectrometer. The program selected for calibrating the flight model is directly linked to the GCMS calibration plan. In order not to pollute the two flight models with products of solid samples such as tholins, we excluded any direct pyrolysis tests through the ACP oven during the first phase of the calibration. Post probe descent simulation of flight results are planned, using the much representative GCMS and ACP spare models. C1 CNRS, Serv Aeron, F-91371 Verrieres Les Buissons, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Res Inst, A-8010 Graz, Austria. Univ Paris 07, LISA, Creteil, France. Univ Paris 12, LISA, Creteil, France. RP Israel, G (reprint author), CNRS, Serv Aeron, F-91371 Verrieres Les Buissons, France. NR 23 TC 16 Z9 16 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 433 EP 468 DI 10.1023/A:1023640723915 PG 36 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100012 ER PT J AU Niemann, HB Atreya, SK Bauer, SJ Biemann, K Block, B Carignan, GR Donahue, TM Frost, RL Gautier, D Haberman, JA Harpold, D Hunten, DM Israel, G Lunine, JI Mauersberger, K Owen, TC Raulin, F Richards, JE Way, SH AF Niemann, HB Atreya, SK Bauer, SJ Biemann, K Block, B Carignan, GR Donahue, TM Frost, RL Gautier, D Haberman, JA Harpold, D Hunten, DM Israel, G Lunine, JI Mauersberger, K Owen, TC Raulin, F Richards, JE Way, SH TI The Gas Chromatograph Mass Spectrometer for the Huygens Probe SO SPACE SCIENCE REVIEWS LA English DT Review ID SUBMILLIMETER HETERODYNE OBSERVATIONS; MOLECULAR-WEIGHT HYDROCARBONS; VOYAGER INFRARED OBSERVATIONS; PLOT CAPILLARY COLUMN; TITANS ATMOSPHERE; CARBON-MONOXIDE; VERTICAL PROFILE; PERMANENT GASES; ABUNDANCE; NITRILES AB The Gas Chromatograph Mass Spectrometer (GCMS) on the Huygens Probe will measure the chemical composition of Titan's atmosphere from 170 km altitude(similar to1 hPa) to the surface (similar to1500 hPa) and determine the isotope ratios of the major gaseous constituents. The GCMS will also analyze gas samples from the Aerosol Collector Pyrolyser (ACP) and may be able to investigate the composition (including isotope ratios) of several candidate surface materials. The GCMS is a quadrupole mass filter with a secondary electron multiplier detection system and a gas sampling system providing continuous direct atmospheric composition measurements and batch sampling through three gas chromatographic (GC) columns. The mass spectrometer employs five ion sources sequentially feeding the mass analyzer. Three ion sources serve as detectors for the GC columns and two are dedicated to direct atmosphere sampling and ACP gas sampling respectively. The instrument is also equipped with a chemical scrubber cell for noble gas analysis and a sample enrichment cell for selective measurement of high boiling point carbon containing constituents. The mass range is 2 to 141 Dalton and the nominal detection threshold is at a mixing ratio of 10(-8). The data rate available from the Probe system is 885 bit/s. The weight of the instrument is 17.3 kg and the energy required for warm up and 150 minutes of operation is 110 Watt-hours. C1 NASA, Greenbelt, MD 20771 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Graz Univ, Inst Meteorol & Geophys, A-8010 Graz, Austria. MIT, Cambridge, MA 01239 USA. Observ Paris, F-92195 Meudon, France. Univ Arizona, Tucson, AZ 85716 USA. CNRS, Serv Aeron, F-91371 Verrieres Les Buissons, France. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Univ Alabama, CMC, Birmingham, AL 35205 USA. Univ Hawaii, Honolulu, HI 96822 USA. Univ Paris 12, Lab Interuniv Syst Atmospher, F-94010 Creteil, France. Univ Paris 07, Lab Interuniv Syst Atmospher, F-94010 Creteil, France. RP Niemann, HB (reprint author), NASA, Greenbelt, MD 20771 USA. RI Harpold, Dan/I-3345-2013; OI Bauer, Siegfried/0000-0003-4213-2047 NR 76 TC 34 Z9 34 U1 0 U2 19 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 553 EP 591 DI 10.1023/A:1023680305259 PG 39 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100014 ER PT J AU Bird, MK Dutta-Roy, R Heyl, M Allison, M Asmar, SW Folkner, WM Preston, RA Atkinson, DH Edenhofer, P Plettemeier, D Wohlmuth, R Iess, L Tyler, GL AF Bird, MK Dutta-Roy, R Heyl, M Allison, M Asmar, SW Folkner, WM Preston, RA Atkinson, DH Edenhofer, P Plettemeier, D Wohlmuth, R Iess, L Tyler, GL TI The Huygens Doppler Wind Experiment - Titan winds derived from probe radio frequency measurements SO SPACE SCIENCE REVIEWS LA English DT Review ID GALILEO PROBE; GENERAL-CIRCULATION; ATMOSPHERE; OCCULTATION; VOYAGER-1; JUPITER; SCIENCE; TEMPERATURE; TRACKING; PROFILE AB A DopplerWind Experiment (DWE) will be performed during the Titan atmospheric descent of the ESA Huygens Probe. The direction and strength of Titan's zonal winds will be determined with an accuracy better than 1 m s(-1) from the start of mission at an altitude of similar to160 km down to the surface. The Probe's wind-induced horizontal motion will be derived from the residual Doppler shift of its S-band radio link to the Cassini Orbiter, corrected for all known orbit and propagation effects. It is also planned to record the frequency of the Probe signal using large ground-based antennas, thereby providing an additional component of the horizontal drift. In addition to the winds, DWE will obtain valuable information on the rotation, parachute swing and atmospheric buffeting of the Huygens Probe, as well as its position and attitude after Titan touchdown. The DWE measurement strategy relies on experimenter-supplied Ultra-Stable Oscillators to generate the transmitted signal from the Probe and to extract the frequency of the received signal on the Orbiter. Results of the first in-flight checkout, as well as the DWE Doppler calibrations conducted with simulated Huygens signals uplinked from ground (Probe Relay Tests), are described. Ongoing efforts to measure and model Titan's winds using various Earth-based techniques are briefly reviewed. C1 Univ Bonn, Inst Radioastron, D-53121 Bonn, Germany. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Idaho, Dept Elect Engn, Moscow, ID 83843 USA. Ruhr Univ Bochum, Inst Hochfrequenztech, D-44801 Bochum, Germany. Univ Roma La Sapienza, Dipartimento Aerospaziale, I-00184 Rome, Italy. Stanford Univ, Ctr Radar Astron, Stanford, CA 94305 USA. RP Bird, MK (reprint author), Univ Bonn, Inst Radioastron, Auf Hugel 71, D-53121 Bonn, Germany. RI IESS, Luciano/F-4902-2011 OI IESS, Luciano/0000-0002-6230-5825 NR 46 TC 28 Z9 28 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 2002 VL 104 IS 1-2 BP 613 EP 640 DI 10.1023/A:1023683004351 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 675RW UT WOS:000182710100016 ER PT S AU Kobel, M Ku, JT AF Kobel, M Ku, JT BE ElGenk, MS TI Comprehensive testing of a neon cryogenic capillary pumped loop SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB This paper describes a comprehensive test program of a cryogenic capillary pumped loop (CCPL) using neon as the working fluid in the temperature range between 30K and 40K. T e test article was originally designed to be used with nitrogen in the 70K to 100K temperature range, and was refurbished for testing with neon. Tests performed included start up from a supercritical state, power cycle, sink temperature cycle, heat transport limit, low power limit, reservoir set point change and long duration operation. The neon CCPL has demonstrated excellent performance under various conditions. C1 NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Greenbelt, MD 20771 USA. RP Kobel, M (reprint author), NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Code 545, Greenbelt, MD 20771 USA. 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 30 EP 36 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200004 ER PT S AU Butler, D Ku, JT Swanson, T AF Butler, D Ku, JT Swanson, T BE ElGenk, MS TI Loop heat pipes and capillary pumped loops - an applications perspective SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Capillary pumped loops (CPLs) and loop heat pipes (LHPs) are versatile two-phase heat transfer devices which have recently gained increasing acceptance in space applications. Both systems work based on the same principles and have very similar designs, Nevertheless, some differences exist in the construction of the evaporator and the hydro-accumulator, and these differences lead to very distinct operating characteristics for each loop, This paper presents comparisons of the two loops from an applications perspective. and addresses their impact on spacecraft design, integration, and test. Some technical challenges and issues for both loops are also addressed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Butler, D (reprint author), NASA, Goddard Space Flight Ctr, Code 545, Greenbelt, MD 20771 USA. NR 9 TC 14 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 49 EP 56 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200006 ER PT S AU Jaworske, DA Hornacek, J AF Jaworske, DA Hornacek, J BE ElGenk, MS TI Thermal performance of an annealed pyrolytic graphite solar collector SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB A solar collector having the combined properties of high solar absorptance, low infrared emittance, and high thermal conductivity is needed for applications where solar energy is to be absorbed and transported for use in minisatellites. Such a solar collector may be used with a low temperature differential heat engine to provide power or with a thermal bus for thermal switching applications. One concept being considered for the solar collector is an Al-Al2O3 cermet coating applied to a thermal conductivity enhanced polished aluminum substrate. The cermet coating provides high solar absorptance and the polished aluminum provides low infrared emittance. Annealed pyrolytic graphite embedded in the aluminum substrate provides enhanced thermal conductivity. The as-measured thermal performance of an annealed pyrolytic graphite thermal conductivity enhanced polished aluminum solar collector, coated with a cermet coating, will be presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Jaworske, DA (reprint author), NASA, Glenn Res Ctr, 21000 Brookport Rd, Cleveland, OH 44135 USA. NR 6 TC 1 Z9 1 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 88 EP 93 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200011 ER PT S AU Reinarts, TR Matson, ML Walls, LK AF Reinarts, TR Matson, ML Walls, LK BE ElGenk, MS TI Corrections for heat flux measurements taken on launch vehicles SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Knowledge of aerothermally induced convective heat transfer and plume induced radiative heat transfer loads is essential to the design of thermal protection systems for launch vehicles. Aerothermal and radiative models are typically calibrated via the data from cylindrical, in-flight, flush-mounted surface heat flux gauges that are exposed to the external thermal and velocity boundary layers as well as thermal radiation. Typically, Schmidt-Boelter gauges, taking advantage of the I-Dimensional Fourier's law, measure the incident heat flux. This instrumentation. when surrounded by low-conductivity insulation, has an exposed surface temperature significantly lower than the insulation. As a result of this substantial disturbance to the thermal boundary layer, the heat flux incident on the gauge tends to be considerably higher (potentially by factors of 2 or more) than it would have been on the insulation had the calorimeter not been there. In addition, the gauge can receive energy radially from the hotter insulation, contributing to the increase of the indicated heat flux. This paper will present an overview of an effort to model the heat flux gauge under typical flight conditions that includes an installation surrounded by high temperature insulation. The goal is to correct the measurements to reflect the local heat flux on the insulation had the instrument not been present. The three major components of this effort include: 1) a 3-Dimensional computational thermal math model including the internal conduction heat transfer details of a Schmidt-Boelter gauge, 2) a CFD analysis to determine the effects on measurement of the rapidly changing thermal boundary layer over the near step changes in wall temperature, and 3) testing performed on flat plates exposed to an aerothermal environment in the Marshall Space Flight Center (MSFC) Improved Hot Gas Facility (IHGF). A summary, of the analytical efforts will be presented, as well as early testing results and preliminary model calibration results. Finally, recommendations will be made for installation and flight data corrections. C1 NASA, KSC, Expendable Launch Vehicles Miss Anal Branch, Kennedy Space Ctr, FL 32899 USA. RP Reinarts, TR (reprint author), NASA, KSC, Expendable Launch Vehicles Miss Anal Branch, VB-A3, Kennedy Space Ctr, FL 32899 USA. NR 8 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 112 EP 118 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200014 ER PT S AU Matson, ML Reinarts, TR AF Matson, ML Reinarts, TR BE ElGenk, MS TI Development and calibration of a thermal model of a Schmidt-Boelter gauge to quantify environmental and installation effects on heat flux measurements for launch vehicles SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Aerothermal heating is the primary driver for launch vehicle external thermal protection system (TPS) design, except for the smaller areas exposed to high plume radiation heating rates. Aerothermal heating models are frequently calibrated via the data from cylindrical, in-flight, flush-mounted surface heat flux gauges. These sensors. typically copper or aluminum Schmidt-Boelter gauges taking advantage of the one-dimensional Fourier's law of heat conduction, are used to measure the incident heat flux. This instrumentation, when surrounded by relatively low-conductivity materials (such as cork), can have wall temperatures significantly lower than the surrounding wall temperature. As a result of this substantial disturbance to the convective heating profile. the heat flux indicated by the gauge tends to be considerably higher (potentially by factors higher than 2) than it would have been had the calorimeter not been there. The contributors to this include thermal boundary layer disturbances and radial conductive heat transfer from the hotter insulation. These measurements, if uncorrected, can lead to highly conservative TPS designs. An effort to quantify the radial conduction effects will be presented here. A three-dimensional computational thermal math model has been developed, and includes the details of a Schmidt-Boelter gauge. These details of the model are presented. Calibration of the model was performed via comparison with data collected on flat plates exposed to an aerothermal environment in the Marshall Space Flight Center (MSFC) Improved Hot Gas Facility (IHGF). The analysis includes a study of the sensitivity of results and corrections to gauge design parameters. Analyzed parameters include gauge orientation (i.e. the direction of the high and low thermopile bead lines) with respect to flow direction, the axial location of the thermopile beads and the separation between the high and low beads, and the contact conductance from the calorimeter to the surrounding material. C1 NASA, KSC, Kennedy Space Ctr, FL 32899 USA. RP Matson, ML (reprint author), NASA, KSC, VB-A3, Kennedy Space Ctr, FL 32899 USA. NR 6 TC 1 Z9 1 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 119 EP 126 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200015 ER PT S AU Douglas, DM Swanson, T Osiander, R Champion, J Darrin, AG Biter, W Chandrasekhar, P AF Douglas, DM Swanson, T Osiander, R Champion, J Darrin, AG Biter, W Chandrasekhar, P BE ElGenk, MS TI Development of the variable emittance thermal suite for the Space Technology 5 microsatellite SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The advent of very small satellites, such as nano and microsatellites. logically leads to a requirement for smaller thermal control subsystems. In addition, the thermal control needs of the smaller spacecraft/instrument may well be different from more traditional situations. For example, power for traditional heaters may be very limited or unavailable, mass allocations may be severely limited, and fleets of nano/microsatellites will require a generic thermal design as the cost of unique designs will be prohibitive. Some applications may require significantly increased power levels while others may require extremely low heat loss for extended periods. Small spacecraft will have low thermal capacitance thus subjecting them to large temperature swings when either the heat generation rate changes or the thermal sink temperature changes. This situation, combined with the need for tighter temperature control, will present a challenging situation during transient operation. The use of "off-the-shelf" commercial spacecraft buses for science instruments will also present challenges. Older thermal technology, such as heaters, thermostats, and heat pipes, will almost certainly not be sufficient to meet the requirements of these new spacecraft/instruments. They are generally too heavy, not scalable to very, small sizes, and may consume inordinate amounts of power. Hence there is a strong driver to develop new technology to meet these emerging needs. Variable emittance coatings offer an exciting alternative to traditional control methodologies and are one of the technologies that will be flown on Space Technology 5, a mission of three microsatellites designed to validate "enabling" technologies. Several studies have identified variable emittance coatings as applicable to wide range of spacecraft, and to potentially offer substantial savings in mass and/or power over traditional approaches. This paper discusses the development of the variable emittance thermal suite for ST-5. More specifically, it provides a description of and the infusion and validation plans for the variable emittance coatings. C1 NASA, Goddard Space Flight Ctr, Thermal Engn Branch, Greenbelt, MD 20771 USA. RP Douglas, DM (reprint author), NASA, Goddard Space Flight Ctr, Thermal Engn Branch, MS 545, Greenbelt, MD 20771 USA. RI Darrin, Margaret/H-4305-2011; Osiander, Robert/J-5781-2015 OI Osiander, Robert/0000-0001-9672-5513 NR 5 TC 8 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 204 EP 210 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200025 ER PT S AU Sunada, E Lankford, K Pauken, M Novak, KS Birur, G AF Sunada, E Lankford, K Pauken, M Novak, KS Birur, G BE ElGenk, MS TI Wax-actuated heat switch for Mars surface applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Missions to the surface of Mars pose unique thermal control challenges to rover and lander systems. With diurnal temperature changes greater than 100 degreesC, the presence of a Mars atmosphere. and limited power for night time heating the thermal control engineer is faced with a fundamental problem: how to successfully keep components above their survival or operating temperatures at night while managing higher environmental temperatures and dissipation rates during the day. Payload and avionics elements, among others, must be well insulated to survive night conditions at the risk of overheating during the day. This problem will be magnified in future missions as higher demand on electrical components will result in increased dissipations. One solution is a heat switch that changes thermal conductance to reject excess heat during the day and conserve heat during the night. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sunada, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 211 EP 213 PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200026 ER PT S AU Golliher, EL AF Golliher, EL BE ElGenk, MS TI Microscale technology electronics cooling overview SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB NASA requirements and subsequent technology solutions for high heat flux electronics are generally different that those for the terrestrial applications. Unlike terrestrial operations, NASA spacecraft have limited opportunities for air cooling, for example, and must rely on less efficient thermal radiation to reject heat to space. The terrestrial commercial electronics industry, as well as other Government agencies, is investing in advanced technologies for electronics cooling at the microscale. This paper gives a brief summary of metrics used in high heat flux electronics cooling, the difference between solutions developed for terrestrial requirements and those for space, and a short description of challenges as well as possible solutions for space-based high heat flux electronics cooling. The argument is made that high heat flux electronics cooling is indeed a core technology required by NASA, since the thermal and other environmental requirements are unique to NASA space missions and are not addressed by current terrestrial electronics cooling technology development projects. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Golliher, EL (reprint author), NASA, Glenn Res Ctr, Mail Stop 301-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 38 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 250 EP 257 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200031 ER PT S AU Curtis, L Johnson, L AF Curtis, L Johnson, L BE ElGenk, MS TI Propulsive Small Expendable Deployer System (ProSEDS) SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta II Expendable Launch Vehicle second stage. ProSEDS, which is planned on an Air Force GPS Satellite replacement mission in June 2002, will use the flight proven Small Expendable Deployer System (SEDS) to deploy a tether (5 kin bare wire plus 10 kin non-conducting Dyneema) from a Delta II second stage to achieve similar to0.4N drag thrust. ProSEDS will utilize the tether-generated current to provide limited spacecraft power. The ProSEDS instrumentation includes Langmuir probes and Differential Ion Flux Probes, which will determine the characteristics of the ambient ionospheric plasma. Two Global Positioning System (GPS) receivers will be used (one on the Delta and one on the endmass) to help determine tether dynamics and to limit transmitter operations to occasions when the spacecraft is over selected ground stations. The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission, which will be capable of orbit raising, lowering and inclination changes-all using electrodynamic thrust. An immediate application of ProSEDS technology is for the removal of spent satellites for orbital debris mitigation. In addition to the use of this technology to provide orbit transfer and debris mitigation it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere. C1 NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. RP Curtis, L (reprint author), NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Huntsville, AL 35812 USA. NR 1 TC 0 Z9 0 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 261 EP 268 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200032 ER PT S AU Horvath, TJ Cheatwood, FM Wilmoth, RG Alter, SJ AF Horvath, TJ Cheatwood, FM Wilmoth, RG Alter, SJ BE ElGenk, MS TI Wake closure characteristics and afterbody heating on a mars sample return orbiter SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Aeroheating wind-tunnel tests were conducted on a 0.028 scale model of an orbiter concept considered for a possible Mars sample return mission. The primary experimental objectives were to characterize hypersonic near wake closure and determine if shear layer impingement would occur on the proposed orbiter afterbody at incidence angles necessary for a Martian acrocapture maneuver. Global heat transfer mappings, surface streamline patterns, and shock shapes were obtained in the NASA Langley 20-Inch Mach 6 Air and CF4 Tunnels for post-normal shock Reynolds numbers (based on forebody diameter) ranging from 1,400 to 415,000, angles of attack ranging from -5 to 10 degrees at 0, 3, and 6 degree sideslip, and normal-shock density ratios of 5 and 12. Laminar, transitional, and turbulent shear layer impingement on the cylindrical afterbody was inferred from the measurements and resulted in a localized heating maximum that ranged from 40 to 75 percent of the reference forebody stagnation point heating. Comparison of laminar heating prediction to experimental measurement along the orbiter afterbody highlight grid alignment challenges associated with numerical simulation of three-dimensional separated wake flows. Predicted values of a continuum breakdown parameter revealed significant regions of non-continuum flow downstream of the flow separation at the MSRO shoulder and in the region of the reattachment shock on the afterbody. The presence of these regions suggest that the Navier-Stokes predictions at the laminar wind-tunnel condition may encounter errors in the numerical calculation of the wake shear layer development and impingement due to non-continuum effects. C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. RP Horvath, TJ (reprint author), NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. NR 42 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 318 EP 336 PG 19 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200040 ER PT S AU Laub, B AF Laub, B BE ElGenk, MS TI New TPS materials for aerocapture SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Many planetary probes, landers and aerocapture concepts are conceived for entry trajectories where peak convective heat flux is in the range 150-400 W/cm(2). This may be too severe an environment for either reusable or low-density ablative materials, The high-density ablatives will work in such environments but the associated TPS weight requirements can be prohibitive. Unfortunately, there are few, if any, well-understood materials that provide reliable, predictable ablative performance for the 150-400 W/cm2 regime while still providing weight efficient TPS solutions. JPL has recently been evaluating an Earth aerocapture demonstration at an entry velocity of approximate to 10 km/s. TPS thickness and areal weight requirements were determined for current ablative TPS candidates (e.g., SLA-561V, PICA) where, for the large integrated heat loads associated with aerocapture, it is shown that some of these materials may not provide efficient thermal protection. A new concept, employing a low catalycity, high emissivity coating on a low-density ceramic tile is evaluated and shown to provide significant benefits for such missions. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Laub, B (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 337 EP 344 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200041 ER PT S AU Masciarelli, JP AF Masciarelli, JP BE ElGenk, MS TI Technology development for deployable aerodynamic decelerators at Mars SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Parachutes used for Mars landing missions are only certified for deployment at Mars behind blunt bodies flying at low angles of attack, Mach numbers up to 2.2, and dynamic pressures of up to 800 Pa. NASA is currently studying entry vehicle concepts for future robotic missions to Mars that would require parachutes to be deployed at higher Mach numbers and dynamic pressures. This paper demonstrates the need for expanding the parachute deployment envelope, and describes a three-phase technology development activity that has been initiated to address the need. The end result of the technology development program will be a aerodynamic decelerator system that can be deployed at Mach numbers of up to 3.1 and dynamic pressures of up to 1400 Pa. C1 NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. RP Masciarelli, JP (reprint author), NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. NR 5 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 345 EP 352 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200042 ER PT S AU Shams, QA Kahng, S Mitchell, M Kuhn, T AF Shams, QA Kahng, S Mitchell, M Kuhn, T BE ElGenk, MS TI A silicon carbide pressure sensor for harsh environment SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies ID MARS GLOBAL SURVEYOR; AEROBRAKING AB Glenn Research Center and Kulite Semiconductor Products have demonstrated, through their preliminary work, applicability of SiC for high-temperature pressure sensing. These experiments conducted on a non-hermetic package have shown survivability and stability up to 500degreesC in a turbine engine environment. These pressure sensors have been fabricated for an upper limit pressure of 1000 psia. For space applications such as Mars Missions, the pressure sensor requirements are stringent in accuracy at a lower range of pressure (25 psia), temperature requirements up to 1000degreesC, and tolerance to radiation. To achieve this goal, new SiC sensors are being developed which will operate at low pressures, 25 psia maximum. This paper will describe the developmental efforts of the low pressure SiC pressure sensor and its preliminary performance characteristics. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Shams, QA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 353 EP 356 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200043 ER PT S AU Fletcher, D AF Fletcher, D BE ElGenk, MS TI Advanced spacecraft designs in support of human missions to Earth's neighborhood SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB NASA's strategic planning for technology investment draws on engineering studies of potential future missions. A number of hypothetical mission architectures have been studied. A recent stud), completed by The NASA/JSC Advanced Design Team addresses one such possible architecture strategy for missions to the moon. This conceptual study presents an overview of each of the spacecraft elements that would enable such missions. These elements include an orbiting lunar outpost at lunar L I called the Gateway, a crew transfer vehicle (CTV) which ferries a crew of four from the ISS to the Gateway, a lunar lander which ferries the crew from the Gateway to the lunar surface, and a one-way lunar habitat lander capable of supporting the crew for 30 days. Other supporting elements of this architecture discussed below include the CTV kickstage, a solar-electric propulsion (SEP) stage, and a logistics lander capable of re-supplying the 30 day habitat lander and bringing other payloads totaling 10.3 mt in support of surface mission activities. Launch vehicle infrastructure to low-earth orbit includes the Space Shuttle, which brings up the CTV and crew, and the Delta-IV Heavy expendable launch vehicle which launches the landers, kickstage, and SEP. C1 NASA, Lyndon B Johnson Space Ctr, Adv Design Off, Houston, TX 77058 USA. RP Fletcher, D (reprint author), NASA, Lyndon B Johnson Space Ctr, Adv Design Off, Houston, TX 77058 USA. NR 2 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 357 EP 364 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200044 ER PT S AU Frisbee, RH AF Frisbee, RH BE ElGenk, MS TI Solar sails for Mars cargo missions SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB This paper presents an analysis of Solar Sails for the Mars Cargo Mission. The figures-of-merit used are the total system Initial Mass in Low Earth Orbit (IMLEO) and Trip Time. The total IMLEO includes the payload, solar sail, and any orbit transfer vehicle (OTV) required to move the sail and its payload to the operational altitude of the sail (e.g., 2.000 km minimum altitude Earth orbit for the solar sail due to air drag). Once the sail and its payload are transported to the sail's minimum operational orbit by the OTV, the sail begins its Earth-escape spiral and heliocentric transfer to the orbit of Mars. In order to minimize the payload's Earth-to-Mars trip time, the sail does not perform a Mars orbit insertion capture spiral but rather deploys its payload during Mars flyby. The payload then aerobrakes into Mars orbit or to the surface to await arrival of the crewed portion of the mission. The sail loiters in heliocentric space until it is time to return to Earth. Note that one important constraint on the payload's Earth-to-Mars trip time is the requirement that the payload be delivered to Mars (and be checked-out and verified operational) before the crew departs Earth at the next Earth-Mars launch opportunity. We further assumed that the solar sail would be a reusable system; thus, in addition to delivering the payload to Mars prior to the next crew departure, the solar sail must return to Earth before the next sail Earth-departure opportunity. With these constraints, the solar sail areas required for a 58 and 72 metric ton (MT) payload are, respectively, 20 and 25 km(2). The corresponding IMLEO values are 149 and 185 MT, such that the total transportation system (sail and OTV) is only 1.6 times the payload mass. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Frisbee, RH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 374 EP 380 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200046 ER PT S AU Marrese-Reading, C Mackie, B Polk, J Jensen, K AF Marrese-Reading, C Mackie, B Polk, J Jensen, K BE ElGenk, MS TI Field emission cathodes for electrodynamic tethers: Identifying compatible cathode materials SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB This extended summary is a preliminary version of the final paper on the progress made in identifying the field emission array cathode materials required for compatibility with the electrodynamic tether application. A description of the desired cathode material characteristics, the materials under investigation, and the rationale for exploring these materials are presented. The work functions of selected material film candidates have been measured before their exposure to oxygen and are included in this summary. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marrese-Reading, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 381 EP 384 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200047 ER PT S AU Curtis, L Vaughn, J Welzyn, K Carroll, J AF Curtis, L Vaughn, J Welzyn, K Carroll, J BE ElGenk, MS TI Development of the flight tether for ProSEDS SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta 11 Expendable Launch Vehicle second stage. ProSEDS will use the flight-proven Small Expendable Deployer System to deploy a newly designed and developed tether which will provide tether generated drag thrust of similar to0.4 N. The development and production of very long tethers with specific properties for performance and survivability will be required to enable future tether missions. The ProSEDS tether design and the development process may provide some lessons learned for these future missions. The ProSEDS system requirements drove the design of the tether to have three different sections of tether each serving a specialized purpose. The tether is a total of 15 kilometers long: 10 kilometers of a non-conductive Dyneema lead tether; 5 km of CCOR conductive coated wire;, and 220 meters of insulated wire with a protective Kevlar overbraid, Production and joining of long tether lengths involved many development efforts. Extensive testing of tether materials including ground deployment of the full-length ProSEDS tether was conducted to validate the tether design and performance before flight. C1 NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Natl Aeronaut & Space Adm, Huntsville, AL 35812 USA. RP Curtis, L (reprint author), NASA, George C Marshall Space Flight Ctr, Space Transportat Directorate, Natl Aeronaut & Space Adm, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 385 EP 392 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200048 ER PT S AU Tucker, S Salvail, P AF Tucker, S Salvail, P BE ElGenk, MS TI Solar-thermal engine testing SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB A solar-thermal engine serves as a high-temperature solar-radiation absorber, heat exchanger, and rocket nozzle, collecting concentrated solar radiation into an absorber cavity and transferring this energy to a propellant as heat. Propellant gas can be heated to temperatures approaching 4,500 degreesF and expanded in a rocket nozzle, creating low thrust with a high specific impulse (I-sp). The Shooting Star Experiment (SSE) solar-thermal engine is made of 100 percent chemically vapor deposited (CVD) rhenium, The engine "module" consists of an engine assembly, propellant feedline, engine support structure, thermal insulation, and instrumentation. Engine thermal performance tests consist of a series of high-temperature thermal cycles intended to characterize the propulsive performance of the engines and the thermal effectiveness of the engine support structure and insulation system. A silicone-carbide electrical resistance heater, placed inside the inner shell, substitutes for solar radiation and heats the engine, Although the preferred propellant is hydrogen, the propellant used in these tests is gaseous nitrogen. Because rhenium oxidizes at elevated temperatures, the tests are performed in a vacuum chamber. Test data will include transient and steady state temperatures on selected engine surfaces, propellant pressures and flow rates, and engine thrust levels. The engine propellant-feed system is designed to supply GN(2) to the engine at a constant inlet pressure of 60 psia, producing a near-constant thrust of 1.0 lb. Gaseous hydrogen will be used in subsequent tests. The propellant flow rate decreases with increasing propellant temperature, while maintaining constant thrust, increasing engine I-sp. In conjunction with analytical models of the heat exchanger, the temperature data will provide insight into the effectiveness of the insulation system, the structural support system, and the overall engine performance. These tests also provide experience on operational aspects of the engine and associated subsystems, and will include independent variation of both steady state heat-exchanger temperature prior to thrust operation and nitrogen inlet pressure (flow rate) during thrust operation. Although the Shooting Star engines were designed as thermal-storage engines to accommodate mission parameters they are fully capable of operating as scalable, direct-gain engines. Tests are conducted in both operational modes. Engine thrust and propellant flow rate will be measured and thereby I.(sp). The objective of these tests is to investigate the effectiveness of the solar engine as a heat exchanger and a rocket. Of particular interest is the effectiveness of the support structure as a thermal insulator, the integrity of both the insulation system and the insulation containment system, the overall temperature distribution throughout the engine module, and the thermal power required to sustain steady state fluid temperatures at various flow rates. C1 NASA, George C Marshall Space Flight Ctr, Marshall Space Flight Ctr, AL 35812 USA. RP Tucker, S (reprint author), NASA, George C Marshall Space Flight Ctr, Marshall Space Flight Ctr, AL 35812 USA. NR 1 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 486 EP 493 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200063 ER PT S AU Wong, WA Castle, CH AF Wong, WA Castle, CH BE ElGenk, MS TI High temperature solar vacuum testing of a sapphire refractive secondary concentrator SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Solar energy can be used in a wide variety of space thermal applications including power generation, thermal propulsion, and high temperature furnaces. The NASA Glenn Research Center (GRC is developing the refractive secondary concentrator. which uses refraction and total internal reflection to concentrate and direct solar energy for these applications. Refractive secondary concentrators, coupled with advanced primary concentrators such as thin film inflatables can efficiently convert solar energy into heat, providing high concentration ratios (10,000:1) and high temperatures (2000 K and higher). Solar vacuum testing on a sapphire refractive secondary concentrator demonstrated 87% throughput efficiency, with projected efficiency of 93% using an anti-reflective coating. Follow-on solar vacuum testing aimed at demonstrating the high temperature capability of the refractive secondary concentrator has recently been completed. The refractive secondary concentrator was coupled with an insulated rhenium receiver and tested in GRC's Tank 6 thermal vacuum facility equipped with a solar simulator. Steady-state receiver temperatures achieved were 1155 K with 0.46 kW input to the refractive secondary concentrator, and 1455 K with 1.25 kW input. A non-steady-state maximum temperature of 1550 K was achieved with input power of 1.96 kW. Presented is a discussion of the test hardware and test results. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Wong, WA (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 494 EP 501 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200064 ER PT S AU Khazanov, GV Stone, NH Krivorutsky, EN AF Khazanov, GV Stone, NH Krivorutsky, EN BE ElGenk, MS TI Current-produced magnetic field effects on current collection SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies ID CYLINDRICAL LANGMUIR PROBES AB Current collection along a realistic "bare wire" space tether is considered. A number of factors are taken into account, including the resistance of the wire and shielding resulting from the current-induced magnetic field produced by current flow in the tether. The plasma density, tether length and radius, the geomagnetic field strength, and angle to the orbital velocity vector were all used as parameters in the study. It is shown that magnetic shielding for certain tether system configurations, when combined with particular values of the governing parameters, significantly reduces the collected current. C1 NASA, Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. RP Khazanov, GV (reprint author), NASA, Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 534 EP 536 PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200069 ER PT S AU Houts, M Van Dyke, M Godfroy, T Pedersen, K Martin, J Dickens, R Salvail, P Hrbud, I Carter, R AF Houts, M Van Dyke, M Godfroy, T Pedersen, K Martin, J Dickens, R Salvail, P Hrbud, I Carter, R BE ElGenk, MS TI Phase 1 space fission propulsion system design considerations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies ID POWER AB Fission technology can enable rapid, affordable access to any point in the solar system. If fission propulsion systems are to be developed to their full potential; however, near-term customers must be identified and initial fission systems successfully developed, launched, and operated. Studies conducted in fiscal year 2001 (IISTP, 2001) show that fission electric propulsion (FEP) systems operating at 80 kWe or above could enhance or enable numerous robotic outer solar system missions of interest. At these power levels it is possible to develop safe, affordable systems that meet mission performance requirements. In selecting the system design to pursue, seven evaluation criteria were identified: safety, reliability, testability, specific mass, cost, schedule, and programmatic risk. A top-level comparison of three potential concepts was performed: an SP-100 based pumped liquid lithium system, a direct gas cooled system, and a heatpipe cooled system. For power levels up to at least 500 kWt (enabling electric power levels of 125-175 Me, given 25-35% power conversion efficiency) the heatpipe system has advantages related to several criteria and is competitive with respect to all. Hardware-based research and development has further increased confidence in the heatpipe approach. Successful development and utilization of a "Phase 1" fission electric propulsion system will enable advanced Phase 2 and Phase 3 systems capable of providing rapid, affordable access to any point in the solar system. C1 NASA, MSFC, Marshall Space Flight Ctr, AL 35812 USA. RP Houts, M (reprint author), NASA, MSFC, TD 40, Marshall Space Flight Ctr, AL 35812 USA. EM michael.houts@msfc.nasa.gov 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 589 EP 595 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200075 ER PT S AU Hrbud, I LaPointe, M Vondra, R Dailey, CL Lovberg, R AF Hrbud, I LaPointe, M Vondra, R Dailey, CL Lovberg, R BE ElGenk, MS TI Status of pulsed inductive thruster research SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The TRW Pulsed Inductive Thruster (PIT) is an electromagnetic propulsion system that can provide high thrust efficiency over a wide range of specific impulse values. In its basic form, the PIT consists of a flat spiral coil covered by a thin dielectric plate. A pulsed gas injection nozzle distributes a thin layer of gas propellant across the plate surface at the same time that a pulsed high current discharge is sent through the coil. The rising current creates a time varying magnetic field, which in turn induces a strong azimuthal electric field above the coil. The electric field ionizes the gas propellant and generates an azimuthal current flow in the resulting plasma. The current in the plasma and the current in the coil flow in opposite directions, providing a mutual repulsion that rapidly blows the ionized propellant away from the plate to provide thrust. The thrust and specific impulse can be tailored by adjusting the discharge power, pulse repetition rate, and propellant mass flow, and there is minimal if any erosion due to the electrodeless nature of the discharge. Prior single-shot experiments performed with a 1-meter diameter version of the PIT at TRW demonstrated specific impulse values between 2,000 seconds and 8,000 seconds, with thruster efficiencies of about 52% for ammonia. This paper outlines current and planned activities to transition the single shot device into a multiple repetition rate thruster capable of supporting NASA strategic enterprise missions. C1 NASA, MSFC Grp, ERC Inc, Huntsville, AL 35812 USA. RP Hrbud, I (reprint author), NASA, MSFC Grp, ERC Inc, Huntsville, AL 35812 USA. NR 15 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 627 EP 632 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200080 ER PT S AU Jones, JA Lorenz, RD AF Jones, JA Lorenz, RD BE ElGenk, MS TI Titan aerover all-terrain vehicle SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB A preliminary design for a Titan mobility system is a modified blimp that can operate in Titan's thick, cold atmosphere as well as drive on its solid surfaces and anticipated liquid hydrocarbon oceans, Testing with models has begun and technology focus areas have been identified as materials, control, navigation, deployment. and power. C1 CALTECH, Mech & Chem Syst Div, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Jones, JA (reprint author), CALTECH, Mech & Chem Syst Div, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 652 EP 657 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200083 ER PT S AU Juhasz, AJ AF Juhasz, AJ BE ElGenk, MS TI A probability analysis of space radiator segmenting for increased reliability and reduced mass SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Spacecraft designed for long duration deep space missions will need to be designed to survive micro-meteoroid bombardment of its surfaces some of which may actually be punctured. To avoid loss of the entire mission the damage due to such punctures must be limited to small, localized areas. This is especially true for power system radiators, which necessarily feature large surface areas to reject heat at relatively low temperature to the space environment by thermal radiation. It may be intuitively obvious, that if a space radiator is composed of a large number of independently operating segments, such as heat pipes, a random micrometeoroid puncture will result only in the loss of the punctured segment, and not the entire radiator. Due to the redundancy achieved by independently operating segments, the wall thickness and consequently the weight of such segments can be drastically reduced. Probability theory is used to estimate the magnitude of such weight reductions as the number of segments is increased. An analysis of relevant parameter values required for minimum mass segmented radiators is also included. C1 Glenn Res Ctr, Natl Aeronaut & Space Adm, Cleveland, OH 44135 USA. RP Juhasz, AJ (reprint author), Glenn Res Ctr, Natl Aeronaut & Space Adm, MS 301-3, Cleveland, OH 44135 USA. NR 5 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 658 EP 665 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200084 ER PT S AU Van Dyke, M Houts, M Godfroy, T Dickens, R Poston, D Kapernick, R Reid, B Salvail, P Ring, P AF Van Dyke, M Houts, M Godfroy, T Dickens, R Poston, D Kapernick, R Reid, B Salvail, P Ring, P BE ElGenk, MS TI Phase 1 space fission propulsion system testing and development progress SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Successful development of space fission systems requires an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. If the system is designed to operate within established radiation damage and fuel burn up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through a series of non-nuclear tests. The Safe Affordable Fission Engine (SAFE) test series, whose ultimate goal is the demonstration of a 300 kW flight configuration system, has demonstrated that realistic testing can be performed using non-nuclear methods. This test series, carried out in collaboration with other NASA centers, other government agencies, industry, and universities, successfully completed a testing program with a 30 kWt core, Stirling engine, and ion engine configuration, Additionally, a 100 kWt core is in fabrication and appropriate test facilities are being reconfigured. This paper describes the cur-rent SAFE non-nuclear tests, which includes test article descriptions, test results and conclusions, and future test plans. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Van Dyke, M (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 3 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 692 EP 697 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200089 ER PT S AU Irvine, C AF Irvine, C BE ElGenk, MS TI Power control of SAFE reactor using fuzzy logic SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Controlling the 100 kW SAFE (Safe Affordable Fission Engine) reactor consists of design and implementation of a fuzzy logic process control system to regulate dynamic variables related to nuclear system power. The first phase of development concentrates primarily on system power startup and regulation, maintaining core temperature equilibrium, and power profile matching. This paper discusses the experimental work performed in those areas. Nuclear core power from the fuel elements is simulated using resistive heating elements while heat rejection is processed by a series of heat pipes. Both axial and radial nuclear power distributions are determined from neutronic modeling codes. The axial temperature profile of the simulated core is matched to the nuclear power profile by varying the resistance of the heating elements. The SAFE model establishes radial temperature profile equivalence by establishing 32 control zones as the nodal coordinates. Control features also allow for slow warm up. since complete shutoff can occur in the heat pipes if heat-source temperatures drop/rise below a certain minimum value, depending on the specific fluid and gas combination in the heat pipe. The entire system is expected to be self-adaptive. i.e., capable of responding to long-range changes in the space environment. Particular attention in the development of the fuzzy logic algorithm shall ensure that the system process remains at set point, virtually eliminating overshoot on start-up and during in-process disturbances. The controller design will withstand harsh environments and applications where it might conic in contact with water, corrosive chemicals, radiation fields, etc. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Irvine, C (reprint author), NASA, George C Marshall Space Flight Ctr, TD40, Huntsville, AL 35812 USA. NR 6 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 711 EP 716 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200091 ER PT S AU Houts, M Kos, L Poston, D AF Houts, M Kos, L Poston, D BE ElGenk, MS TI Potential operating orbits for fission electric propulsion systems driven by the SAFE-400 SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Safety must be ensured during all phases of space fission system design, development, fabrication. launch, operation, and shutdown. One potential space fission system application is fission electric propulsion (FEP), in which fission energy is converted into electricity and used to power high efficiency (Isp > 3000s) electric thrusters. For these types of systems it is important to determine which operational scenarios ensure safety while allowing maximum mission performance and flexibility. Space fission systems are essentially nonradioactive at launch, prior to extended operation at high power. Once high power operation begins, system radiological inventory steadily increases as fission products build up. For a given fission product isotope, the maximum radiological inventory is typically achieved once the system has operated for a length of time equivalent to several half-lives. After that time, the isotope decays at the same rate it is produced, and no further inventory builds in. For an FEP mission beginning in Earth orbit, altitude and orbital lifetime increase as the propulsion system operates. Two simultaneous effects of fission propulsion system operation are thus (1) increasing fission product inventory and (2) increasing orbital lifetime. Phrased differently, as fission products build up, more time is required for the fission products to naturally convert back into non-radioactive isotopes, Simultaneously, as fission products build up, orbital lifetime increases, providing more time for the fission products to naturally convert back into non-radioactive isotopes. Operational constraints required to ensure safety can thus be quantified. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Houts, M (reprint author), NASA, George C Marshall Space Flight Ctr, TD40, Huntsville, AL 35812 USA. EM michael.houts@msfc.nasa.gov NR 6 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 717 EP 721 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200092 ER PT S AU Carter, R Roman, J Salvail, P AF Carter, R Roman, J Salvail, P BE ElGenk, MS TI Manufacturing development for the SAFE 100 kW core SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB In stark contrast to what is sometimes considered the norm in traditional manufacturing processes, engineers at the Marshall Space Flight Center (MSFC) are in the practice of altering the standard in an effort to realize other potential methods in core manufacturing. While remaining within the bounds of the materials database, we are researching into core manufacturing techniques that may, have been overlooked in the past due to funding and/or time constraints. To augment proven core fabrication capabilities we are pursuing plating processes as another possible method for core build-up and assembly. Although brazing and a proprietary HIP cycle are used for module assembly (proven track record for stability and endurance), it is prudent to pursue secondary or backup methods of module and core assembly. For this reason heat tube manufacture and module assembly by means of plating is being investigated, Potentially. the plating processes will give engineers the ability to manufacture replacement modules for an), module that might fail to perform nominally, and to assemble/disassemble a complete core in much less time than would be required for the conventional Braze-HIP process. Another area of improvement in core manufacturing capabilities is the installation of a sodium and lithium liquid metal heat pipe fill machine. This, along with the ability to Electron Beam Weld heat pipe seals and wet-in the pipes in the necessary vacuum atmosphere, will eliminate the need to ship potentially hazardous components outside for processing. In addition to developing core manufacturing techniques, the SAFE manufacturing team has been evaluating the thermal heat transfer characteristics, and manufacturability, of several heat exchanger design concepts. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Carter, R (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 726 EP 731 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200094 ER PT S AU Martin, L Lewis, R Chakrabarti, S Pearson, B AF Martin, L Lewis, R Chakrabarti, S Pearson, B BE ElGenk, MS TI Ion storage tests with the High Performance Antiproton Trap (HiPAT) SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies ID CONFINEMENT AB The matter antimatter reaction represents the densest form of energy storage/release known to modern physics: as such it offers one of the most compact sources of power for future deep space exploration. To take the first steps along this path, the NASA-MSFC is developing a storage system referred to as the High Performance Antiproton Trap (HiPAT) with a goal of maintaining 10(12) particles for up to 18 days. Experiments have been performed with this hardware using normal matter (positive hydrogen ions) to assess the device's ability to hold charged particles. These ions are currently created using an electron gun method to ionize background gas; however, this technique is limited by the quantity that can be captured. To circumvent this issue, an ion source is currently being commissioned which will greatly increase the number of ions captured and more closely simulate actual operations expected at an antiproton production facility. Ions have been produced, stored for various time intervals, and then extracted against detectors to measure species, quantity and energy. Radio frequency stabilization has been tested as a method to prolong ion lifetime: results show an increase in the baseline 1/e lifetime of trapped particles from hours to days. Impurities in the residual background gas (typically carbon-containing species CH4, CO, CO2, etc.) present a continuing problem by reducing the trapped hydrogen population through the mechanism of ion charge exchange. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Martin, L (reprint author), NASA, George C Marshall Space Flight Ctr, TD40, Huntsville, AL 35812 USA. NR 20 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 793 EP 800 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200103 ER PT S AU Emrich, WJ AF Emrich, WJ BE ElGenk, MS TI Current status of the gasdynamic mirror fusion propulsion experiment SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP Conference Proceedings LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Nuclear fusion appears to be the most promising concept for producing extremely high specific impulse rocket engines. One particular fusion concept which seems to be particularly well suited for fusion propulsion applications is the gasdynamic mirror (GDM). An experimental GDM device has been constructed at the NASA Marshall Space Flight Center to provide an initial assessment of the feasibility of this type of propulsion system. An initial shakedown of the device is currently under-way with initial experiments slated to occur in late 2001. This device would operate at much higher plasma densities and with much larger L/D ratios than previous mirror machines. The high L/D ratio minimizes to a large extent certain magnetic curvature effects which lead to plasma instabilities causing a loss of plasma confinement. The high plasma density results in the plasma behaving much more like a conventional fluid with a mean free path shorter than the length of the device. This characteristic helps reduce problems associated with "loss cone" microinstabilities. The device has been constructed to allow a considerable degree of flexibility in its configuration thus permitting the experiment to grow over time without necessitating a great deal of additional fabrication. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Emrich, WJ (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM bill.emrich@msfc.nasa.gov 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 801 EP 806 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200104 ER PT S AU Schreiber, JG Skupinski, RC AF Schreiber, JG Skupinski, RC BE ElGenk, MS TI Accomplishments in free-piston Stirling tests at NASA GRC SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB A power system based on the Stirling Radioisotope Generator (SRG) has been identified for potential use on deep space missions, as well as for Mars rovers that may benefit from extended operation. The Department of Energy (DOE) has responsibility for developing the generator and the NASA Glenn Research Center (GRC) is supporting DOE in this effort. The generator is based on a free-piston Stirling power convertor that has been developed by the Stirling Technology Company (STC) under contract to DOE. The generator would be used as a high-efficiency alternative to the Radioisotope Thermoelectric Generators (RTGs) that have been used on many previous missions. The increased efficiency leads to a factor of 3 to 4 reduction in the inventory of plutonium required to heat the generator. GRC has been involved in the development of Stirling power conversion technology for over 25 years. The support provided to this project by GRC has many facets and draws upon the lab's scientists and engineers that have gained experience in applying their skills to the previous Stirling projects. This has created a staff with an understanding of the subtleties involved in applying their expertise to Stirling systems. Areas include materials, structures, tribology, controls, electromagnetic interference, permanent magnets, alternator analysis, structural dynamics, and cycle performance. One of the key areas of support to the project is in the performance testing of the free-piston Stirling convertors. Since these power convertors are the smallest, lowest power Stirling machines that have been tested at GRC, a new laboratory was equipped for this project. Procedures and test plans have been created, instrumentation and data systems developed, and Stirling convertors have been tested. This paper will describe the GRC test facility, the test procedures that are used, present some of the test results and outline plans for the future. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Schreiber, JG (reprint author), NASA, Glenn Res Ctr Lewis Field, MS 301-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 5 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 857 EP 864 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200111 ER PT S AU Mason, LS Shaltens, RK Dolce, JL Cataldo, RL AF Mason, LS Shaltens, RK Dolce, JL Cataldo, RL BE ElGenk, MS TI Status of Brayton cycle power conversion development at NASA GRC SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The NASA Glenn Research Center is pursuing the development of Brayton cycle power conversion for various NASA initiatives. Brayton cycle power systems offer numerous advantages for space power generation including high efficiency, long life, high maturity, and broad scalability. Candidate mission applications include surface rovers and bases, advanced propulsion vehicles, and earth orbiting satellites. A key advantage is the ability for Brayton converters to span the wide range of power demands of future missions from several kilowatts to multi-megawatts using either solar, isotope, or reactor heat sources. Brayton technology has been under development by NASA since the early 1960's resulting in engine prototypes in the 2 to 15 kW-class that have demonstrated conversion efficiency of almost 30% and cumulative operation in excess of 40,000 hours. Present efforts at GRC are focusing on a 2 kW testbed as a proving ground for future component advances and operational strategies, and a 25 kW engine design as a modular building block for 100 kW-class electric propulsion and Mars surface power applications. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Mason, LS (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 5 TC 8 Z9 8 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 865 EP 871 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200112 ER PT S AU Thieme, LG Schreiber, JG Mason, LS AF Thieme, LG Schreiber, JG Mason, LS BE ElGenk, MS TI Stirling technology development at NASA GRC SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The Department of Energy, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC) are developing a free-piston Stirling convertor for a high-efficiency Stirling Radioisotope Generator (SRG) for NASA Space Science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. NASA GRC is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. Recent testing of 55-We Technology Demonstration Convertors (TDC's) built by STC includes mapping of a second pair of TDC's. single TDC testing, and TDC electromagnetic interference and electromagnetic compatibility characterization on a non-magnetic test stand. Launch environment tests of a single TDC without its pressure vessel to better understand the convertor internal structural dynamics and of dual-opposed TDC's with several engineering mounting structures with different natural frequencies have recently been completed, A preliminary life assessment has been completed for the TDC heater head, and creep testing of the IN718 material to be used for the flight convertors is underway. Long-term magnet aging tests are continuing to characterize any potential aging in the strength or demagnetization resistance of the magnets used in the linear alternator (LA). Evaluations are now beginning on key organic materials used in the LA and piston/rod surface coatings. GRC is also conducting finite element analyses for the LA, in part to look at the demagnetization margin on the permanent magnets. The world's first known integrated test of a dynamic power system with electric propulsion was achieved at GRC when a Hall-effect thruster was successfully operated with a free-piston Stirling power source. Cleveland State University is developing a multi-dimensional Stirling computational fluid dynamics code to significantly improve Stirling loss predictions and assist in identifying convertor areas for further improvements. This paper will update the status and results for these efforts. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Thieme, LG (reprint author), NASA, Glenn Res Ctr Lewis Field, MS 301-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 11 TC 14 Z9 14 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 872 EP 879 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200113 ER PT S AU Halford, GR Shah, A Arya, VK Krause, DL Bartolotta, PA AF Halford, GR Shah, A Arya, VK Krause, DL Bartolotta, PA BE ElGenk, MS TI Structural analyses of Stirling power-convertor heater head for long-term reliability, durability, and performance SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB Deep space missions require onboard electric power systems with reliable design lifetimes of up to 10-y and beyond. A high-efficiency Stirling radioisotope power system is a prime candidate for future deep space missions and Mars rover applications, To ensure ample durability, the structurally critical Heater Head of the Stirling Power-Convertor has undergone extensive computational analyses of operating temperatures (up to 650 degreesC). stresses, and creep-resistance of the thin-walled Inconel 718 bill-of-material. Durability predictions are presented in terms of probability of survival. A benchmark" structural testing program has commenced to support the analyses, This paper reports the current status of our durability assessments. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Halford, GR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 4 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 880 EP 887 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200114 ER PT S AU Suarez, VJ Goodnight, TW Hughes, WO Samorezov, S AF Suarez, VJ Goodnight, TW Hughes, WO Samorezov, S BE ElGenk, MS TI Impact testing of a Stirling convertor's linear alternator SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure and results of the impact testing conducted on the Stirling TDC in May 2001. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Suarez, VJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 3 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 888 EP 897 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200115 ER PT S AU Goodnight, TW Suarez, VJ Hughes, WO Samorezov, S AF Goodnight, TW Suarez, VJ Hughes, WO Samorezov, S BE ElGenk, MS TI Effect of structural mount dynamics on a pair of operating Stirling convertors SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic base-shake tests were conducted on a dynamic simulation of the structural mount for a pair of Operating Stirling Convertors. These tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of these tests vas to identify the changes in transmissibility and the effect on structural dynamic response on a pair of operating Stirling Technology Demonstration Convertors (TDCs). This paper addresses the base-shake test, setup, procedure and results conducted on the Stirling TDC mount simulator in April 2001. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Goodnight, TW (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 5 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 918 EP 928 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200119 ER PT S AU Clements, GR AF Clements, GR BE ElGenk, MS TI The Advanced Technology Development Center (ATDC) SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-STAIF 2002 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF 2002) CY FEB 03-06, 2002 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Mech Engineers, IEEE, Inst Space & Nucl Power Studies AB NASA is building the Advanced Technology Development Center (ATDC) to provide a "national resource" for the research, development, demonstration, testing, and qualification of Spaceport and Range Technologies. The ATDC will be located at Space Launch Complex 20 (SLC-20) at Cape Canaveral Air Force Station (CCAFS) in Florida. SLC-20 currently provides a processing and launch capability for small-scale rockets this capability will be augmented with additional ATDC facilities to provide a comprehensive and integrated in situ environment, Examples of Spaceport Technologies that ill be supported by ATDC infrastructure include densified cryogenic systems, intelligent automated umbilicals, integrated vehicle health management systems, next-generation safety systems, and advanced range systems, The ATDC can be thought of as a prototype spaceport where industry. government, and academia, in partnership, can work together to improve safety of future space initiatives. The ATDC is being deployed in five separate phases. Major ATDC facilities will include a Liquid Oxygen Area (Phase 1): a Liquid Hydrogen Area, a Liquid Nitrogen Area, and a multipurpose Launch Mount (Phase 2) "Iron Rocket" Test Demonstrator (Phase 3): a Processing Facility with a Checkout and Control System (Phase 4); and Future Infrastructure Developments (Phase 5). Initial ATDC development will be completed in 2006. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Clements, GR (reprint author), NASA, YA-E6, Kennedy Space Ctr, FL 32899 USA. NR 1 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 0-7354-0052-0 J9 AIP CONF PROC PY 2002 VL 608 BP 1197 EP 1204 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA BV21Q UT WOS:000178182200154 ER PT B AU Lepping, RP Berdichevsky, D Szabo, A Lazarus, AJ Thompson, BJ AF Lepping, RP Berdichevsky, D Szabo, A Lazarus, AJ Thompson, BJ BE Lyu, LH TI Upstream shocks and interplanetary magnetic cloud speed and expansion: Sun, wind, and earth observations SO SPACE WEATHER STUDY USING MULTIPOINT TECHNIQUES SE COSPAR COLLOQUIA SERIES LA English DT Proceedings Paper CT 12th COSPAR Colloquium on Space Weather Study Using Multipoint Techniques CY SEP 27-29, 2000 CL TAIPEI, TAIWAN SP Comm Space Res, Acad Sinica, Minist Educ, Natl Sci Council, Natl Space Program Off, Natl Cent Univ, Natl Cheng Kung Univ, Sci Comm Solar Terrestrial Phys ID SOLAR-WIND; FIELD; DYNAMICS; DST; AU AB Identifications have been made of the probable sources on the Sun (from SOHO data), where possible, of the magnetic clouds observed by WIND near Earth over the span of about 4 years (1995-1998), i.e., mainly during the quiet solar phase. The timing of the probable source transients at the Sun allow the estimations of transit times from the Sun to Earth for a set of 20 magnetic clouds with the result that acceleration effects in the interplanetary medium appear to be small. For a larger set of magnetic clouds (N = 27) it is found that the relative speed of the front part of a cloud at 1 AU (its ramming speed) correlates better than cloud expansion with the existence of an upstream interplanetary shock. Hence, cloud expansion is not likely the primary agent responsible for clouds driving shocks. Approximately 1/2 of the magnetic clouds (i.e., 14 cases) were accompanied by upstream shocks, and for an additional 1/4 of the cases pressure pulses ahead of the magnetic clouds were present. It is shown that these upstream shocks (or pressure pulses) are well correlated with SSC's at Earth. We also examine the effects of the engulfing of the magnetosphere by the shocked solar wind-magnetic cloud complex, by comparing the integrated solar wind Poynting flux input (Sigma epsilonDeltat = energy, where epsilon is the Akasofu epsilon-function) with the associated minimum Dst, and we develop a formal relationship between them. C1 NASA, Goddard Space Flight Ctr, Lab Extraterr Phys, Greenbelt, MD 20771 USA. RP Lepping, RP (reprint author), NASA, Goddard Space Flight Ctr, Lab Extraterr Phys, Greenbelt, MD 20771 USA. RI Thompson, Barbara/C-9429-2012 NR 22 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND BN 0-08-044057-6 J9 COSPAR COLL PY 2002 VL 12 BP 87 EP 96 PG 10 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BV25Z UT WOS:000178343300010 ER PT B AU Tsurutani, BT Arballo, JK Zhou, XY Galvan, C Chao, JK AF Tsurutani, BT Arballo, JK Zhou, XY Galvan, C Chao, JK BE Lyu, LH TI Electromagnetic electron and proton cyclotron waves in geospace: A Cassini snapshot SO SPACE WEATHER STUDY USING MULTIPOINT TECHNIQUES SE COSPAR COLLOQUIA SERIES LA English DT Proceedings Paper CT 12th COSPAR Colloquium on Space Weather Study Using Multipoint Techniques CY SEP 27-29, 2000 CL TAIPEI, TAIWAN SP Comm Space Res, Acad Sinica, Minist Educ, Natl Sci Council, Natl Space Program Off, Natl Cent Univ, Natl Cheng Kung Univ, Sci Comm Solar Terrestrial Phys ID EARTHS BOW SHOCK; SOLAR-WIND; LION ROARS; ULYSSES OBSERVATIONS; ALFVEN WAVES; HYDROMAGNETIC-WAVES; MIRROR WAVES; PLASMA SHEET; NOVEMBER 1; UPSTREAM AB The Cassini spacecraft flew past the Earth in a trajectory almost along the Sun-Earth line, giving a unique perspective of low frequency waves in geospace. Geotail was immediately upstream of the bow shock nose, allowing for an accurate assessment of the solar wind conditions driving geospace macroscale processes, the latter of which led to microinstabilities and electromagnetic plasma wave growth. We demonstrate the presence of nonlinear cyclotron waves in the foreshock, magnetosheath, outer magnetosphere, and tail lobe. A predominance of right-hand cyclotron waves with f approximate to 1.0 Hz (in the spacecraft frame) are detected in the foreshock. The waves are compressional with Delta(B) over bar /B-0 similar to0.25. It is argued that these waves are propagating in the electron cyclotron (whistler) mode and that the waves are generated by low-energy electrons streaming into the upstream region with parallel kinetic energies of tens of eV. This region appears to be a pure electron foreshock. The magnetosheath waves are the largest amplitude (similar to15 nT peak-to-peak in a similar to30 nT field) proton cyclotron waves detected in geospace. The wave amplitudes are largest near the bow shock and decrease to similar to8 nT peak-to-peak near the magnetopause. No discernible mirror mode structures were detected in the magnetosheath. It is possible that a low abundance of He++ ions in the solar wind high-speed stream may be the cause of the ion cyclotron wave dominance, as previously predicted by theory. However, other explanations are possible as well. The outer magnetospheric proton cyclotron waves are of low intensity (similar to4 nT peak-to-peak), and can cause weak proton pitch angle diffusion and concomitant diffuse proton aurora. Large-scale solar wind ram pressure pulses do not appear to be the cause of the magnetospheric waves. However, small scale fluctuations are possible. Two new low-intensity wave modes are identified in the tail lobes associated with substorm events. One mode is a transverse, elliptically polarized similar to7.5 s wave and the other is a purely compressional (similar to0.1 nT amplitude) wave, with a similar to8 s quasiperiod. The latter mode is propagating obliquely (similar to70degrees to 84degrees) to the magnetic field. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 58 TC 3 Z9 3 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND BN 0-08-044057-6 J9 COSPAR COLL PY 2002 VL 12 BP 97 EP 125 PG 29 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BV25Z UT WOS:000178343300011 ER PT B AU Zhou, XY Tsurutani, BT AF Zhou, XY Tsurutani, BT BE Lyu, LH TI Interplanetary shock effects on the nightside auroral zone, magnetosphere and ionosphere SO SPACE WEATHER STUDY USING MULTIPOINT TECHNIQUES SE COSPAR COLLOQUIA SERIES LA English DT Proceedings Paper CT 12th COSPAR Colloquium on Space Weather Study Using Multipoint Techniques CY SEP 27-29, 2000 CL TAIPEI, TAIWAN SP Comm Space Res, Acad Sinica, Minist Educ, Natl Sci Council, Natl Space Program Off, Natl Cent Univ, Natl Cheng Kung Univ, Sci Comm Solar Terrestrial Phys ID PLASMA SHEET; SOLAR-WIND; SUBSTORMS; RECONNECTION; FIELD; GROWTH AB Responses of the nightside magnetosphere and auroral zone to interplanetary shocks are studied using WIND solar wind data and POLAR UV imaging data. It is found that the nightside magnetospheric/ionospheric response depends on the interplanetary magnetic field upstream of the shock. When the IMF B., is strongly southward upstream (up to 1.5 hr) of the shock, a substorm expansion phase is triggered by the shock. If the IMF B-z is similar to0, the interplanetary shock triggers a pseudobreakup. If the B-z is northward, the shock does not trigger nightside auroral activity. Shock compression effects on the magnetotail are discussed, as well as potential substorm triggering mechanisms. A schematic model for tail plasma "loading" and "unloading" is presented. One conclusion of this paper is that it may now be possible to predict what type of auroral activity occurs after interplanetary shock impingement on the magnetosphere/magnetotail. A "dripping, tilting bucket" model is presented to explain the observations. The model incorporates the possibility that the magnetotail has a nonlinear response to unusually strong interplanetary shocks. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zhou, XY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI KIDLINGTON PA THE BOULEVARD, LANGFORD LANE,, KIDLINGTON OX5 1GB, OXFORD, ENGLAND BN 0-08-044057-6 J9 COSPAR COLL PY 2002 VL 12 BP 139 EP 147 PG 9 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BV25Z UT WOS:000178343300013 ER PT B AU Vassiliadis, D Klimas, AJ Ahn, BH Parks, RJ Viljanen, A Yumoto, K AF Vassiliadis, D Klimas, AJ Ahn, BH Parks, RJ Viljanen, A Yumoto, K BE Lyu, LH TI High-latitude electrodynamics from a multi-array nonlinear geomagnetic model SO SPACE WEATHER STUDY USING MULTIPOINT TECHNIQUES SE COSPAR COLLOQUIA SERIES LA English DT Proceedings Paper CT 12th COSPAR Colloquium on Space Weather Study Using Multipoint Techniques CY SEP 27-29, 2000 CL TAIPEI, TAIWAN SP Comm Space Res, Acad Sinica, Minist Educ, Natl Sci Council, Natl Space Program Off, Natl Cent Univ, Natl Cheng Kung Univ, Sci Comm Solar Terrestrial Phys ID INTERPLANETARY MAGNETIC-FIELD; ALIGNED CURRENTS; ELECTRIC-FIELDS; NORTHERN AB We present a model for the high-latitude geomagnetic disturbances with the goal of studying the time-dependent solar wind-magnetosphere-ionosphere coupling. This nonlinear dynamical model, very different from earlier linear approaches, is based on observations from the WIND and ACE solar wind monitors and the IMAGE and MM210 ground magnetometer arrays. The model performance is evaluated in several activity intervals and shows that the overall amplitude of the disturbance is predicted moderately well. The electrojets and other large-scale spatial structures, however, are not reproduced at a satisfactory level at present, so higher-order terms need to be calculated with an expanded database. A coupling of the model to the KRM electrodynamic model and the Ahn et al. [1998] conductance forms the basis of a prediction system for the high-latitude ionospheric circuit. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NR 11 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 0-08-044057-6 J9 COSPAR COLL PY 2002 VL 12 BP 231 EP 236 PG 6 WC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Meteorology & Atmospheric Sciences GA BV25Z UT WOS:000178343300022 ER PT S AU Macala, GA AF Macala, GA BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Design of the Reaction Wheel Attitude Control system for the Cassini spacecraft SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper presents the architecture and methodology used for the design of the Cassini spacecrafts Reaction Wheel Attitude Controller. Simulation results are presented that predict the pointing performance. Preliminary in-flight pointing performance results are also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Macala, GA (reprint author), CALTECH, Jet Prop Lab, MS 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 2 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 303 EP 315 PN 1&2 PG 13 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800019 ER PT S AU Chang, L Brown, JM Barltrop, KJ Lee, AY AF Chang, L Brown, JM Barltrop, KJ Lee, AY BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Use of guidance and control test cases to verify spacecraft attitude control system design SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB A simulation and analysis approach is introduced for verification of attitude control flight software performance in a deep space mission. The Cassini Guidance and Control test cases simulate typical and mission-critical spacecraft scenarios under nominal and stress conditions. Plots compare simulation results against "pass/fail" curves traced back to functional requirements, The analysis also provides useful insight into performance margin. Comparisons of test results with flight telemetry provide an assessment of simulation fidelity. The method demonstrates the value of software simulation in qualifying an attitude control system to perform in the expected environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chang, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 317 EP 337 PN 1&2 PG 21 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800020 ER PT S AU Gabor, MJ AF Gabor, MJ BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Progress report on US Space Command astrodynamic standards effort SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB United States Space Command is assembling a set of astrodynamic standards that will apply to the space surveillance mission. The goals of the standards development process are to ensure the maximum amount of accuracy while satisfying the need for interoperability. This will hopefully result in less stove-piping between the Air Force and the Navy systems. These standards will apply to the space control centers as they satisfy their space surveillance mission requirements and then to the users of the space control centers' products. While the specifics of the policy have not yet been established, the standards will be subject to periodic review and modification. Current progress includes establishing initial proposals for gravity, solar radiation pressure, 3rd body perturbations, and numerical integration. Future work will focus on other perturbations, orbit determination, and eventually other astrodynamic applications. C1 US Space Command, Anal Directorate, Peterson AFB, CO 80914 USA. RP Gabor, MJ (reprint author), US Space Command, Anal Directorate, Peterson AFB, CO 80914 USA. NR 18 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 373 EP 385 PN 1&2 PG 13 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800024 ER PT S AU Highsmith, DE AF Highsmith, DE BE Alfriend, KT Neta, B Luu, K Walker, CAH TI The effect of USO stability on one-way Doppler navigation of the Mars Reconnaissance Orbiter SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper provides a summary of a study to assess the effect of the stability of the ultra-stable oscillator on board the Mars Reconnaissance Orbiter (Mars 2005 mission) on navigation accuracy when using one-way Doppler to the Deep Space Network. The focus of this study is ephemeris reconstruction accuracy of one-way Doppler-only solutions, where the metrics are reconstruction requirements and the expected two-way Doppler error levels. Subject to the assumptions of the covariance analysis, the results indicate that an oscillator with 1 x 10(-12) short-term stability would provide navigation performance sufficient to meet the ephemeris requirements, but a 1 x 10-(13) oscillator would ensure minimal loss of performance versus the nominal two-way Doppler. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Highsmith, DE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 529 EP 539 PN 1&2 PG 11 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800034 ER PT S AU Roth, DC Guman, AD Ionasescu, R AF Roth, DC Guman, AD Ionasescu, R BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Cassini orbit reconstruction from earth to Jupiter SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB This paper describes Cassini reconstructed orbit determination results from the Earth flyby through the Jupiter flyby. Emphasis is placed on orbit determination modeling and the resulting orbit solution. Cassini's encounter with Jupiter occurred on 30 December 2000, with a periapsis time of 10:04:21.870 UTC. Its position relative to Jupiter at closest approach, mapped to the B-plane (see Appendix for B-plane description) in Earth-Mean-Orbital coordinates of J2000, was B.T = 10,896,977 km and B-R = 123,778 km. Formal filtered uncertainties yielded a B-plane error ellipse with a semi-major axis of 115 km, semi-minor axis of 0.6 km, and an orientation angle of 90.7degrees. The one sigma uncertainty in the time of closest approach was 0.08 seconds. C1 CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, Pasadena, CA 91109 USA. RP Roth, DC (reprint author), CALTECH, Jet Prop Lab, Navigat & Mission Design Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 693 EP 704 PN 1&2 PG 12 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800046 ER PT S AU Wawrzyniak, GG Lisano, ME AF Wawrzyniak, GG Lisano, ME BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Using inertial measurements for the reconstruction of 6-DOF entry, descent, and landing trajectory and attitude profiles SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB A method was sought for estimating the "stroke" distance between a Mars Exploration Rover (MER) test lander (protected by airbags) and a surface during impact. The authors at JPL have developed a suite of software known as REDLand (for Reconstruction of Entry, Descent and Landing) to accomplish this. REDLand uses data from accelerometers and gyroscopes on board the lander test body as measurements in an extended Kalman filter, in addition to geometric and dynamical constraints, and other data, where available. This paper is a discussion of the formulation of the REDLand filter algorithms and presents results from actual MER airbag-and-lander impact tests made in 2001. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wawrzyniak, GG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 775 EP 794 PN 1&2 PG 20 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800052 ER PT S AU Franz, H AF Franz, H BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Design of earth return orbits for the wind mission SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID TRAJECTORIES AB Since its launch on November 1, 1994, NASA's Interplanetary Physics Laboratory, or Wind spacecraft, has exploited the potential of lunar gravity assist flybys to drastically alter the spacecraft's trajectory, allowing Wind to fly an orbital profile that would have been impossible with reliance on propulsive delta-V (DeltaV) maneuvers alone. To implement the Wind trajectory, each lunar flyby is designed not only to effect the large-scale orbital modifications necessary for initiating the next mission phase, but also to establish the timing and geometry required for subsequent encounters with the Moon. This paper documents a Wind trajectory design that was completed in the Spring of 2001. The design proposed that Wind's 37th lunar flyby in December 2003 would propel the spacecraft into a nightside Earth Return Orbit (ERO), which represents a periodic solution to Hill's formulation of the restricted three-body problem. The apogees of Wind's ERO would reach a maximum distance of 400 Earth radii (2.6 million kilometers), a limit dictated by the spacecraft's communications subsystem. The ERO apogees would occur near the maximum excursion from the Sun-Earth line, alternately leading arid trailing the Earth in its orbit about the Sun. In addition, a novel sequence of lunar flybys would allow Wind to cycle between nightside and dayside EROS. C1 NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Franz, H (reprint author), NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RI Franz, Heather/F-3508-2012 NR 11 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 845 EP 865 PN 1&2 PG 21 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800056 ER PT S AU Quadrelli, MB AF Quadrelli, MB BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Effect of distributed rod and string flexibility on formation dynamic stability SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB We study the effect of distributed elasticity on the dynamics of an orbiting formation. The paradigm considered in the paper, namely two bodies connected by one spring in formation with a separated free-flying body, represents a prototype system for a variety of possible problems. Conclusions are derived on the system's stability, as well as on the system performance under closed-loop control. C1 CALTECH, Jet Prop Lab, Guidance & Control Anal Grp, Pasadena, CA 91109 USA. RP Quadrelli, MB (reprint author), CALTECH, Jet Prop Lab, Guidance & Control Anal Grp, Mail Stop 198-326,4800 Oak Drove 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 1237 EP 1255 PN 1&2 PG 19 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800077 ER PT S AU Whiffen, GJ Sims, JA AF Whiffen, GJ Sims, JA BE Alfriend, KT Neta, B Luu, K Walker, CAH TI Application of the SDC optimal control algorithm to low-thrust escape and capture trajectory optimization SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB An application of the new optimization algorithm called Static/Dynamic Control (SDC) to design low-thrust escape and capture trajectories is presented. SDC is a general optimization method that is distinct from both parameter optimization and the calculus of variations. Trajectories are integrated with a multi-body force model and feature solar electric propulsion with a specific impulse that is a function of the engine throttle. The test problems include interplanetary scale trajectories that capture or escape at one of the inner planets. Optimizing capture and escape trajectories with a multi-body force model results in a significant improvement in the mass delivered compared to existing two-body formulations. SDC is robust for this application and does not require a good initial guess. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Whiffen, GJ (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, 4800 Oak Gorve Dr, Pasadena, CA 91109 USA. NR 6 TC 6 Z9 6 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 1361 EP 1382 PN 1&2 PG 22 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800084 ER PT S AU Morris, DG Burke, ES AF Morris, DG Burke, ES BE Alfriend, KT Neta, B Luu, K Walker, CAH TI The RAPSO process SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Jet Propulsion Laboratory's Resource Allocation Planning and Scheduling Office is chartered to divide the limited amount of tracking hours of the Deep Space Network amongst the various missions in as equitable allotment as can be achieved. To best deal with this division of assets and time, an interactive process has evolved that promotes discussion with agreement by consensus between all of the customers that use the Deep Space Network (DSN). Aided by a suite of tools, the task of division of asset time is then performed in three stages of granularity. Using this approach, DSN loads are either forecasted or scheduled throughout a moving 10-year window. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Morris, DG (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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 1475 EP 1486 PN 1&2 PG 12 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800092 ER PT S AU Kehrbaum, JM Kim, KK AF Kehrbaum, JM Kim, KK BE Alfriend, KT Neta, B Luu, K Walker, CAH TI The DSN viewperiods used for a mission - A look at the times when communication windows can be scheduled between the DSN and the projects SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The Jet Propulsion Laboratory Resource Allocation, Planning and Scheduling Office (JPL-RAPSO) is chartered to allocate the limited amount of tracking hours among the various missions in as equitable allotment as can be achieved. The communication windows that can be used for communication between the ground and the Project/spacecraft are called "viewperiods." The concept of the viewperiods for (any) mission is presented in this paper, along with the levels of refinement over time (Forecasting/Project/Mid-Range/NSS) associated with those viewperiods. C1 CALTECH, Jet Prop Lab, Mission Engn & Planning Grp, User Technol Associates, Pasadena, CA 91109 USA. RP Kehrbaum, JM (reprint author), CALTECH, Jet Prop Lab, Mission Engn & Planning Grp, User Technol Associates, 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 1487 EP 1493 PN 1&2 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800093 ER PT S AU Lacey, N Morris, DG AF Lacey, N Morris, DG BE Alfriend, KT Neta, B Luu, K Walker, CAH TI JPL RAPSO long-range forecasting SO SPACEFLIGHT MECHANICS 2002, VOL 112, PTS I AND II SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/AIAA 12th Space Flight Mechanics Meeting CY JAN 27-30, 2002 CL SAN ANTONIO, TX SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut AB The JPL RAPSO is chartered to divide the limited amount of tracking hours amongst the various missions in as equitable allotment as can be achieved. This paper introduces the concept of the long-range forecasting function, which is performed by the group. This is then used to identify periods of peak oversubscription of resources years before they actually happen, so that proper corrective actions (construction of additional antennas, reduction in support commitment to the impacted projects) can be implemented. C1 CALTECH, Jet Prop Lab, Lockheed Martin Informat Technol, Pasadena, CA 91109 USA. RP Lacey, N (reprint author), CALTECH, Jet Prop Lab, Lockheed Martin Informat Technol, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 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 0-87703-495-8 J9 ADV ASTRONAUT SCI PY 2002 VL 112 BP 1495 EP 1508 PN 1&2 PG 14 WC Automation & Control Systems; Engineering, Aerospace; Instruments & Instrumentation; Mechanics SC Automation & Control Systems; Engineering; Instruments & Instrumentation; Mechanics GA BV43H UT WOS:000178928800094 ER PT S AU Kallman, TR AF Kallman, TR BE Back, CA TI Astrophysical x-ray lines observed by Chandra and XMM SO SPECTRAL LINE SHAPES SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 16th International Conference on Spectral Line Shapes CY JUN 03-07, 2002 CL UNIVB CALIF BERKELEY, BERKELEY, CA SP Univ Calif Davis, Lawrence Livermore Natl Lab HO UNIVB CALIF BERKELEY ID PHOTOIONIZATION AB This paper reviews the capabilities of Chandra and XMM and discusses some of the physical processes affecting line broadening in X-ray astronomy. Broadening due to relativistic effects is a process which is unique to this field, and which provides important insight into the nature of cosmic X-ray sources. The challenge of interpreting X-ray spectra is illustrated with an example of a well-known active galaxy, and the effect of line broadening on the K shell opacity of iron is discussed. C1 NASA, Goddard Space Flight Ctr, LHEA, Greenbelt, MD 20771 USA. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, LHEA, Code 665, Greenbelt, MD 20771 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 0-7354-0100-4 J9 AIP CONF PROC PY 2002 VL 645 BP 131 EP 138 PG 8 WC Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical SC Physics GA BV93T UT WOS:000180453100015 ER PT J AU Lowenthal, MS Khanna, RK Moore, MH AF Lowenthal, MS Khanna, RK Moore, MH TI Infrared spectrum of solid isocyanic acid (HNCO): vibrational assignments and integrated band intensities SO SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY LA English DT Article DE isocyanic acid; infrared spectroscopy; solid-state; absolute intensities; interstellar ices ID MICRON ABSORPTION AB Infrared spectra of thin films of solid I-INCO condensed from the gas phase are characterized in terms of their vibrational frequencies, mode assignments, and integrated band intensities at low temperatures (similar to 20-145 K). Isocyanic acid is shown to react with water (H2O) and ammonia (NH3) even at low temperatures; consequently, it may be an important species in the chemistry of interstellar ices and comets. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lowenthal, MS (reprint author), Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NR 16 TC 39 Z9 39 U1 3 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1386-1425 J9 SPECTROCHIM ACTA A JI Spectroc. Acta Pt. A-Molec. Biomolec. Spectr. PD JAN 1 PY 2002 VL 58 IS 1 BP 73 EP 78 DI 10.1016/S1386-1425(01)00524-8 PG 6 WC Spectroscopy SC Spectroscopy GA 501XM UT WOS:000172711400006 PM 11817367 ER PT J AU Moles, A Holland, L Short, J AF Moles, A Holland, L Short, J TI Effectiveness in the laboratory of Corexit 9527 and 9500 in dispersing fresh, weathered, and emulsion of Alaska North Slope crude oil under subarctic conditions SO SPILL SCIENCE & TECHNOLOGY BULLETIN LA English DT Article DE dispersant; effectiveness; Corexit 9527; Corexit 9500; temperature; salinity; Alaska North Slope crude oil AB The effect of various states of weathering (no weathering, 20% evaporatively weathered, and emulsification) on the effectiveness of oil dispersants Corexit 9527 and 9500 in dispersing Alaska North Slope crude oil into the water column was tested under laboratory conditions at a combination of realistic subarctic salinities and temperatures. A modified version of the swirling flask effectiveness test was conducted at temperatures of 3, 10 and 22 degreesC with salinities of 22parts per thousand and 32parts per thousand. Petroleum dispersed into the water column following application of dispersant was measured by gas chromatography with flame ionization detection. Based on comparison of unresolved complex mixtures, dispersants dispersed less than 40% of the fresh oil and less than 10% of the weathered oil and were most effective (25-75%) when used to disperse a stable oil/water emulsion at 10 degreesC. At the combinations of temperature and salinity most common in the estuaries and marine waters of Alaska, dispersants effectiveness was less than 10%, the detection limits of the tests. The results indicate that oil weathering state, seawater salinity and temperature are important factors affecting dispersant performance, however because our laboratory tests were conducted at low mixing energy, considerable caution should be used in extrapolating these laboratory studies to field conditions. Published by Elsevier Science Ltd. C1 Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. RP Moles, A (reprint author), Natl Marine Fisheries Serv, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 13 TC 17 Z9 19 U1 2 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1353-2561 J9 SPILL SCI TECHNOL B JI Spill Sci. Technol. Bull. PY 2002 VL 7 IS 5-6 BP 241 EP 247 AR PII S1353-2561(02)00041-5 DI 10.1016/S1353-2561(02)00041-5 PG 7 WC Engineering, Environmental; Engineering, Petroleum SC Engineering GA 628MQ UT WOS:000179999800009 ER PT B AU Hunter, GW Neudeck, PG Okojie, RS Beheim, GM Thomas, V Chen, L Lukco, D Liu, CC Ward, B Makel, D AF Hunter, GW Neudeck, PG Okojie, RS Beheim, GM Thomas, V Chen, L Lukco, D Liu, CC Ward, B Makel, D BE Kopf, RF Ren, F Stokes, EB Ng, HM Baca, AG Pearton, SJ Chu, SNG TI Development of SiC gas sensor systems SO STATE-OF-THE-ART PROGRAM ON COMPOUND SEMICONDUCTORS XXXVI AND WIDE BANDGAP SEMICONDUCTORS FOR PHOTONIC AND ELECTRONIC DEVICES AND SENSORS II SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 2nd Wide Bandgap Semiconductors for Photonic and Electronic Devices and Sensors/36th State-of-the-Art Program on Compound Semiconductors International Symposia CY MAY 12-17, 2002 CL PHILADELPHIA, PA SP Electrochem Soc, Electr Div, Electrochem Soc, Sensor Div ID SILICON-CARBIDE; METAL AB Silicon carbide (SiC) based gas sensors-have significant potential to address them gas sensing needs of aerospace applications such as emission monitoring, fuel leak detection, and fire detection. However, in order to reach that potential, a range of technical challenges must be overcome. These challenges go beyond the development of the basic sensor itself and include the need for viable enabling technologies to make a complete gas sensor system: electrical contacts, packaging, and transfer of information from the sensor to the outside world. This paper reviews the status at NASA Glenn Research Center of SiC Schottky diode gas sensor development as well as that of enabling technologies supporting SiC gas sensor system implementation. A vision of a complete high temperature microfabricated SiC gas sensor system is proposed. In the long-term, it is believed that improvements in the SiC semiconductor material itself could have a dramatic effect on the performance of SiC gas sensor systems. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hunter, GW (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 26 TC 5 Z9 5 U1 0 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-369-5 J9 ELEC SOC S PY 2002 VL 2002 IS 3 BP 93 EP 111 PG 19 WC Endocrinology & Metabolism; Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics; Physics, Condensed Matter SC Endocrinology & Metabolism; Engineering; Instruments & Instrumentation; Optics; Physics GA BW02Z UT WOS:000180671100012 ER PT B AU Firestone, ER AF Firestone, ER GP STC STC TI Scientific writing and editing: Problems, pitfalls, and pratfalls SO STC'S 49TH ANNUAL CONFERENCE, PROCEEDINGS: LEADING THE TECHNICAL COMMUNICATION REVOLUTION LA English DT Proceedings Paper CT 49th Annual Conference of the Society-for-Technical-Communication CY MAY 05-08, 2002 CL NASHVILLE, TN SP Soc Tech Commun AB Clear and concise scientific communication is a goal to strive for at all times. To achieve this clear and concise prose, however, is not the responsibility of just the scientist-author or just the editor, but an integrated team of both. What happens, however, when this "team" or "partnership" does not work? This paper will explore different problems editors might face in a scientific workplace and how the problems can be either fixed altogether or at least alleviated. C1 NASA, Goddard Space Flight Ctr, SAIC, Greenbelt, MD 20771 USA. RP Firestone, ER (reprint author), NASA, Goddard Space Flight Ctr, SAIC, Code 970-2, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SOC TECHNICAL COMMUNICATION PI ARLINGTON PA 901 N STUART ST, SUITE 904, ARLINGTON, VA 22203-1854 USA BN 1-891709-12-7 PY 2002 BP 394 EP 397 PG 4 WC Computer Science, Information Systems SC Computer Science GA BV03X UT WOS:000177666000095 ER PT S AU Batalha, NM Jenkins, J Basri, GS Borucki, WJ Koch, DG AF Batalha, NM Jenkins, J Basri, GS Borucki, WJ Koch, DG BE Battrick, B TI Stellar variability and its implications for photometric planet detection with Kepler SO STELLAR STRUCTURE AND HABITABLE PLANET FINDING, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 1st Eddington Workshop on Stellar Structure and Habitable Planet Finding CY JUN 11-15, 2001 CL CORDOBA, SPAIN SP European Space Agcy, Ctr Astrobiol DE stars : activity; planets : exoplanets ID MAIN-SEQUENCE STARS; SUN-LIKE STARS; CA-II H; CHROMOSPHERIC VARIATIONS; EMISSION; ROTATION; IRRADIANCE; FIELD AB Kepler is one of three candidates for the next NASA Discovery Mission and will survey the extended solar neighborhood to detect and characterize hundreds of terrestrial (and larger) planets in or near the habitable zone. Its strength lies in its ability to detect large numbers of Earth-sized planets - planets which produce a 10(-4) change in relative stellar brightness during a transit across the disk of a sun-like parent star. Such a detection requires high instrumental relative precision and is facilitated by observing stars which are photometrically quiet on hourly timescales, Probing stellar variability across the HR diagram, one finds that many of the photometrically quietest stars are the F and G dwarfs. The Hipparcos photometric database shows the lowest photometric variances among stars of this spectral class. Our own Sun is a prime example with RMS variations over a few rotational cycles of typically 3 - 4 x 10(-4) (computed from VIRGO/DIARAD data taken Jan-Mar 2001). And variability on the hourly time scales crucial for planet detection is significantly smaller: just 2 - 5 x 10(-5). This bodes well for planet detection programs such as Kepler and Eddington, With significant numbers of photometrically quiet solar-type stars, Earth-sized planets should be readily identified provided they are abundant in the solar neighborhood. In support of the Kepler science objectives, we have initiated a study of stellar variability and its implications for planet detection, Herein, we summarize existing observational and theoretical work with the objective of determining the percentage of stars in the Kepler field of view expected to be photometrically stable at a level which allows for Earth-sized planet detection. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Batalha, NM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 26 TC 12 Z9 12 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-781-X J9 ESA SP PUBL PY 2002 VL 485 BP 35 EP 40 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU45P UT WOS:000176018800005 ER PT S AU Gopalswamy, N Kaiser, ML AF Gopalswamy, N Kaiser, ML BE Gibson, S Suess, ST TI Solar eruptions and long wavelength radio bursts: The 1997 May 12 event SO STRUCTURE, ENERGETICS AND DYNAMICS OF THE CORONA AND THE HELIOSPHERE DURING THE RISING PHASE OF THE 23RD SOLAR CYCLE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2/D2 2 Symposium of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID CORONAL MASS EJECTIONS; WIND SPACECRAFT; ORIGIN; SHOCKS; WAVES AB We report on the cause of the 1997 May 12 type II bursts observed by ground based and space-based radio instruments. We estimate the fast mode speed in the corona as a function of heliocentric distance to identify the regions where fast mode shocks can be driven by CMEs. We find that both the coronal and the interplanetary type II bursts can be explained by shocks driven by the same CME at two different spatial domains. The fast mode speed in the corona has a peak at a heliocentric distance of similar to 3 R-circle dot which does not allow the coronal shock wave to propagate beyond this distance. When the CME continues to travel beyond the fast mode peak, another shock forms in the interplanetary medium where the fast mode speed falls sufficiently. From the radio observations we can infer that the plane of the sky speed of the CME is smaller than the space speed by at least a factor of 2, consistent with the location of the eruption at N21 W08. The inferred CME speed is also consistent with previous deprojected speed estimates. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gopalswamy, N (reprint author), Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. RI Gopalswamy, Nat/D-3659-2012 NR 17 TC 24 Z9 24 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 3 SI 2002 BP 307 EP 312 AR PII S0273-1177(01)00589-0 DI 10.1016/S0273-1177(01)00589-0 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT86F UT WOS:000174269800003 ER PT S AU Fludra, A Ireland, J Del Zanna, G Thompson, WT AF Fludra, A Ireland, J Del Zanna, G Thompson, WT BE Gibson, S Suess, ST TI The solar corona in Cycle 23 SO STRUCTURE, ENERGETICS AND DYNAMICS OF THE CORONA AND THE HELIOSPHERE DURING THE RISING PHASE OF THE 23RD SOLAR CYCLE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2/D2 2 Symposium of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID DIAGNOSTIC SPECTROMETER; ACTIVE REGIONS; MAGNETIC-FIELD; ULTRAVIOLET; SOHO AB The Coronal Diagnostic Spectrometer (CDS) on SOHO has been recording EUV spectra and monitoring time variability of EUV line intensities, electron temperature and density in the low solar corona during the rising part of Cycle 23. The four-year data set includes daily synoptic observations in four EUV lines along the central meridian since April 1996 and weekly diagnostic observations above the polar coronal holes since July 1997. The history of line intensities along the central meridian, and radial profiles of electron temperature and density above the polar regions at heights up to 1.15R(circle dot), are derived. EUV line intensities and photospheric magnetic flux are also calculated for 50 active regions observed from 1996 to June 1998. Variability of temperature, density, and EUV spectral line intensities in the polar coronal holes, quiet sun and active regions with the solar cycle is discussed. Power-law relationships among the EUV line intensities from the CDS synoptic data, and also between the EUV line intensities and magnetic field flux in active regions are presented. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 9EW, England. RP Fludra, A (reprint author), Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. RI Thompson, William/D-7376-2012 NR 9 TC 8 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 3 SI 2002 BP 361 EP 372 AR PII S0273-1177(01)00598-1 DI 10.1016/S0273-1177(01)00598-1 PG 12 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT86F UT WOS:000174269800012 ER PT S AU Ratkiewicz, R Barnes, A Muller, HR Zank, GP Webb, GM AF Ratkiewicz, R Barnes, A Muller, HR Zank, GP Webb, GM BE Gibson, S Suess, ST TI Modeling the heliosphere: Influence of the interstellar magnetic field in the presence of LISM neutral hydrogen SO STRUCTURE, ENERGETICS AND DYNAMICS OF THE CORONA AND THE HELIOSPHERE DURING THE RISING PHASE OF THE 23RD SOLAR CYCLE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2/D2 2 Symposium of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID NONUNIFORM SOLAR-WIND; SIMULATION AB In this paper we use the best currently available estimates for interstellar parameters to calculate several models of the interaction between the solar wind and the magnetized interstellar plasma in the presence of LISM neutral hydrogen. We show how the heliosphere may be modified by both the galactic magnetic field and neutral particles. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Ctr Space Res, PL-00716 Warsaw, Poland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Ratkiewicz, R (reprint author), Ctr Space Res, Bartycka 18A, PL-00716 Warsaw, Poland. NR 18 TC 7 Z9 7 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 3 SI 2002 BP 433 EP 438 AR PII S0273-1177(01)00608-1 DI 10.1016/S0273-1177(01)00608-1 PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT86F UT WOS:000174269800022 ER PT S AU Whang, YC Burlaga, LF AF Whang, YC Burlaga, LF BE Gibson, S Suess, ST TI Voyager crossing of the termination shock: Prediction SO STRUCTURE, ENERGETICS AND DYNAMICS OF THE CORONA AND THE HELIOSPHERE DURING THE RISING PHASE OF THE 23RD SOLAR CYCLE SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E2 2/D2 2 Symposium of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Comm Space Res ID ANOMALOUS COSMIC-RAYS; SOLAR-WIND; DISTANT HELIOSPHERE; OUTER HELIOSPHERE AB This paper studies the varying location and conditions of the termination shock over 34-year period (1966 - 2000). The shock location is anti-correlated with the sunspot number, moving inward or outward during the rising or declining phase of the solar cycle. For the shock in the upwind direction, plasma and magnetic field conditions in its immediately upstream are extrapolated from 1 AU data using MHD equations including pickup protons, and the shock location estimated by the ACR spectrum is used as a guide. Voyager 1 will cross the termination shock in the region of high-speed solar wind at latitude of similar to34degrees. Taking into consideration the high-latitude effects, the calculation indicates that the shock is now moving inward to within 85 AU. Voyager 1 could cross the shock around Year 2002, and the crossing may occur 3 or more times over a period of about 4 years. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Whang, YC (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 2002 VL 29 IS 3 SI 2002 BP 445 EP 450 AR PII S0273-1177(01)00610-X DI 10.1016/S0273-1177(01)00610-X PG 6 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT86F UT WOS:000174269800024 ER PT J AU Sun, HJ Depriest, PT Gargas, A Rossman, AY Friedmann, EI AF Sun, HJ Depriest, PT Gargas, A Rossman, AY Friedmann, EI TI Pestalotiopsis maculans: A dominant parasymbiont in North American lichens SO SYMBIOSIS LA English DT Article DE lichenicolous fungi; lichen symbiosis; Pestalotiopsis ID FUNGAL AB By culturing small thallus portions in nutrient medium, we showed that Pestalotiopisis maculans (Corda) Nag Raj is a dominant parasymbiont (secondary fungus) in North American lichens. P. maculans was present in all twelve lichen specimens (10 Cladonia, 1 Usnea, and 1 Parmetroma) studied in the eastern North America between Ontario, Canada and Oaxaca, Mexico. In each lichen P. maculans was present throughout the length of the thallus. Cultures of excised tissue samples revealed that in the Cladonia thallus P. maculans is confined to the medulla, but not in direct contact with the photobiont cells contained therein. When growing in pure culture, P. maculans and the mycobiont Cladonia subtenuis show different hyphal morphologies in the environmental scanning electron microscope, but these characteristics are not present within the lichen thallus. Twenty-one lichens collected in Germany, the Canary Islands, New Zealand, and Israel contained other secondary fungi (but not Pestalotiopsis) with variable abundance and relatively narrow geographic distribution. C1 Florida State Univ, Dept Sci Biol, Tallahassee, FL 32306 USA. Smithsonian Inst, Natl Museum Nat Hist, US Natl Herbarium, MRC 166, Washington, DC 20013 USA. USDA ARS, Beltsville, MD 20705 USA. Florida State Univ, Polar Desert Res Ctr, Tallahassee, FL 32306 USA. RP Sun, HJ (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-301, Pasadena, CA 91109 USA. RI DePriest, Paula/K-6633-2015 NR 16 TC 8 Z9 9 U1 0 U2 1 PU INT SCIENCE SERVICES/BALABAN PUBLISHERS PI REHOVOT PA PO BOX 2039, REHOVOT 76120, ISRAEL SN 0334-5114 J9 SYMBIOSIS JI Symbiosis PY 2002 VL 33 IS 3 BP 215 EP 226 PG 12 WC Microbiology SC Microbiology GA 634DT UT WOS:000180325300002 ER PT B AU Stajner, I Rood, RB Winslow, N AF Stajner, I Rood, RB Winslow, N GP AMS AMS TI Impact of covariance modeling and data selection on assimilated ozone SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID SYSTEM C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Stajner, I (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. RI Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 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 2002 BP 35 EP 36 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100010 ER PT B AU Atlas, R AF Atlas, R GP AMS AMS TI Observing system forecast experiments at the DAO SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID WIND; PREDICTION; WEATHER; IMPACT C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Atlas, R (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 37 EP 39 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100011 ER PT B AU Tangborn, A Menard, R Ortland, D AF Tangborn, A Menard, R Ortland, D GP AMS AMS TI Assimilation of HRDI Line-of-Sight winds SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc AB The High Resolution Doppler Imager (HRDI) provides direct global scale measurement of the stratospheric and upper troposphere wind field. We have incorporated these observations into the GEOS-DAS assimilation system and present here results on the impact of these observations on the stratospheric wind analyses. While HRDI Line-of-Sight (LOS) observations have relatively large errors, they can be separated by observational parameters (eg. Absorption band), and the observation error for some data subsets have substantially smaller errors than the entire set of observations. Further, direct assimilation of LOS winds removes the retrieval into (U,V) wind components so that a more accurate determination of the observation errors can be made. Accurate knowledge of observation errors is as important to assimilation as the accuracy of the observations themselves. We show that the HRDI observations have significant on the analysis winds and that the short term assimilation results indicate that there is some promise for increasing the accuracy of stratospheric wind fields. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Tangborn, A (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 44 EP 46 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100013 ER PT B AU Roy, B Halverson, JB AF Roy, B Halverson, JB GP AMS AMS TI On quality control procedures being adopted for TRMM LBA and KWAJEX soundings data sets SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID TEMPERATURE C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Roy, B (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 63 EP 68 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100018 ER PT B AU Borovikov, A Rienecker, MM AF Borovikov, A Rienecker, MM GP AMS AMS TI Multivariate forecast error covariances for an ocean model estimated by Monte-Carlo simulation SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID EQUATORIAL PACIFIC-OCEAN C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Borovikov, A (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Code 971, Greenbelt, MD 20771 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 82 EP 85 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100022 ER PT B AU Sun, CJ Walker, JP Houser, P AF Sun, CJ Walker, JP Houser, P GP AMS AMS TI Snow assimilation in a catchment-based land surface model using the extended Kalman filter SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID CIRCULATION C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sun, CJ (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 974, Greenbelt, MD 20771 USA. RI Sun, Chaojiao/A-9569-2011; Houser, Paul/J-9515-2013 OI Sun, Chaojiao/0000-0002-7030-0485; Houser, Paul/0000-0002-2991-0441 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 2002 BP 89 EP 91 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100025 ER PT B AU Troccoli, A Rienecker, MM AF Troccoli, A Rienecker, MM GP AMS AMS TI The importance of salinity in the assimilation of temperature observations in the tropical pacific ocean SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID EL-NINO; MODEL C1 Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Troccoli, A (reprint author), Goddard Space Flight Ctr, Oceans & Ice Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RI Troccoli, Alberto/A-1477-2012 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 2002 BP 107 EP 110 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100029 ER PT B AU Reichle, RH Koster, RD Walker, JP Rienecker, MM Houser, RR AF Reichle, RH Koster, RD Walker, JP Rienecker, MM Houser, RR GP AMS AMS TI Aspects of the extended and ensemble Kalman filters for land data assimilation in the NASA seasonal-to-interannual prediction project SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID MODEL C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reichle, RH (reprint author), NASA, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI Reichle, Rolf/E-1419-2012; Koster, Randal/F-5881-2012; Houser, Paul/J-9515-2013 OI Koster, Randal/0000-0001-6418-6383; Houser, Paul/0000-0002-2991-0441 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 2002 BP 111 EP 112 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100030 ER PT B AU Keppenne, CL Rienecker, MM AF Keppenne, CL Rienecker, MM GP AMS AMS TI Multivariate assimilation of altimetry into an OGCM with diagnostic sea-surface height using the ensemble Kalman filter SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID OCEAN MODEL C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Keppenne, CL (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 971, Greenbelt, MD 20771 USA. NR 10 TC 1 Z9 1 U1 1 U2 1 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 158 EP 163 PG 6 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100041 ER PT B AU Todling, R Yang, RH Guo, J Cohn, SE AF Todling, R Yang, RH Guo, J Cohn, SE GP AMS AMS TI Estimation of analysis error variances with the physical-space statistical analysis system SO SYMPOSIUM ON OBSERVATIONS, DATA ASSIMILATION, AND PROBABILISTIC PREDICTION LA English DT Proceedings Paper CT Symposium on Observations, Data Assimilation, and Probabilistic Prediction CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc 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. RI Cohn, Stephen/K-1954-2012 OI Cohn, Stephen/0000-0001-8506-9354 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 2002 BP 178 EP 182 PG 5 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Remote Sensing; Water Resources GA BV53Y UT WOS:000179290100045 ER PT S AU Hand, C AF Hand, C BE Valafar, F TI Epicenter location by analysis of interictal spikes - A case study for the use of artificial neural networks in biomedical engineering SO TECHNIQUES IN BIOINFORMATICS AND MEDICAL INFORMATICS SE Annals of the New York Academy of Sciences LA English DT Article; Proceedings Paper CT International Conference on Mathematics and Engineering Techniques in Medicine and Biological Sciences CY JUN 25-28, 2001 CL LAS VEGAS, NV SP Comp Sci Res, Educ & Appl Press, Int Technol Inst, Korea Informat Proc Soc, World Acad Sci Informat Technol, PACT Corp, Comp Vis Res & Appl Tech, Java High Performance Comp Res Grp, Sundance Digital Signal Proc Inc DE epilepsy; MEG; interictal spikes; artificial neural networks AB Artificial neural network (ANN) technology is finding increasing application in medicine and biomedical engineering. This paper supplies necessary background in ANN technology for researchers unfamiliar with this rapidly emerging discipline. This introduction to ANN application is cast in the context of epileptic seizure epicenter location. This is a very real problem faced by neurosurgeons every day. Precise location of the area of excision is currently determined with a network of surgically implanted subdural electrodes. This means that the cure entails two surgical procedures: one to implant the electrode array that precisely locates the epicenter, and another to remove the epicenter. This paper outlines an experimental diagnostic software system (DSS) that uses artificial neural network (ANN) analysis of magnetoencephalographic (MEG) data to eliminate the first of these surgical procedures. The MEG recording is a quick and painless process that requires no surgery. This approach has the potential to save time, reduce patient discomfort, and eliminate a painful and potentially dangerous surgical step in the treatment procedure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CBEAR Syst Inc, 1800 Loma Vista, Pasadena, CA 91104 USA. EM cbear@speakeasy.net NR 25 TC 4 Z9 4 U1 1 U2 2 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-433-1; 1-57331-432-3 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 2002 VL 980 BP 306 EP 313 PG 8 WC Medical Informatics; Multidisciplinary Sciences SC Medical Informatics; Science & Technology - Other Topics GA BW14C UT WOS:000180980600024 PM 12594100 ER PT S AU Diftler, MA Jenks, KC Williams, LEP AF Diftler, MA Jenks, KC Williams, LEP BE Stein, MR TI Robonaut: A telepresence-based astronaut assistant SO TELEMANIPULATOR AND TELEPRESENCE TECHNOLOGIES VIII SE Proceedings of SPIE LA English DT Proceedings Paper CT 8th Conference on Telemanipulator and Telepresence Technologies CY OCT 28, 2001 CL NEWTON, MA SP SPIE DE anthropomorphic robots; telepresence; space robots; dexterous robots; distributed architecture; teleoperation AB Robonaut, NASA's latest anthropomorphic robot, is designed to work in the hazards of the space environment as both an astronaut assistant and, in certain situations, an astronaut surrogate. This highly dexterous robot is now performing complex tasks under telepresence control in the Dexterous Robotics Laboratory at the Johnson Space Center that could previously only be carried out directly by humans. With 43 degrees of freedom (DOF), Robonaut is a state-of-the-art human size telemanipulator system. It has a three-DOF articulated waist and two seven-DOF arms, giving it an impressive work space for interacting with its environment. Its two five-fingered hands allow manipulation of a wide range of common tools. A pan/tilt head with multiple stereo camera systems provides data for both teleoperators and computer vision systems. Telepresence control is the main mode of operation for Robonaut. The teleoperator dons a variety of sensors to map hand, head, arm and body motions to control the robot. A distributed object-oriented network architecture links the various computers used to gather posture and joint angle data from the human operator, to control the robot, to generate video displays for the human operator and to recognize and generate human voice inputs and outputs. Distributed object-oriented software allows the same telepresence gear to be used on different robots and allows interchangeable telepresence gear in the laboratory environment. New telepresence gear and new robots only need to implement a standard software interface. The Robonaut implementation is a two-tiered system using Java/Jini(TM) for distributed commands and a commercial-off-the-shelf data sharing protocol for high-speed data transmission. Experimental telepresence gear is being developed and evaluated. Force feedback devices and techniques are a focus, and their effects on teleoperator performance of typical space operations tasks is being measured. Particularly, the augmentation of baseline Robonaut teleoperation control techniques with force feedback information is shown to significantly reduce potentially damaging contact forces and improve operator consistency. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 10 TC 0 Z9 0 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4298-4 J9 PROC SPIE PY 2002 VL 4570 BP 142 EP 152 DI 10.1117/12.454740 PG 11 WC Automation & Control Systems; Engineering, Electrical & Electronic; Optics SC Automation & Control Systems; Engineering; Optics GA BU21T UT WOS:000175366100017 ER PT J AU Fletcher, GD Gordon, MS Bell, RS AF Fletcher, GD Gordon, MS Bell, RS TI Gradient of the ZAPT2 energy SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Article DE analytical derivative; Moller-Plesset; perturbation theory; high-spin state ID PLESSET PERTURBATION-THEORY; RESTRICTED HARTREE-FOCK; OPEN-SHELL SYSTEMS; WAVE-FUNCTIONS; SPIN ORBITALS; DERIVATIVES; CONVERGENCE; MOLECULES; SERIES AB An explicit expression for the analytical first derivative of the Z-averaged perturbation theory taken to second order energy, due to Lee and Jayatilaka, is presented for application to high-spin systems described by a restricted open-shell Hartree-Fock wavefunction. The use of frozen core orbitals is incorporated into the derivation. C1 NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA. RP Fletcher, GD (reprint author), NASA, Ames Res Ctr, ELORET Corp, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 31 TC 17 Z9 17 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD JAN PY 2002 VL 107 IS 2 BP 57 EP 70 DI 10.1007/s00214-001-0304-z PG 14 WC Chemistry, Physical SC Chemistry GA 528FA UT WOS:000174232700001 ER PT S AU Winfree, WP Zalameda, JN AF Winfree, WP Zalameda, JN BE Maldague, XP Rozlosnik, AE TI Single sided thermal diffusivity imaging in composites with a shuttered thermographic inspection system SO THERMOSENSE XXIV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Thermosense XXIV Conference CY APR 01-04, 2002 CL ORLANDO, FL SP SPIE DE infrared; thermal; NDE; thermal diffusivity; composites AB A measurement configuration is discussed where shutters are placed in front of the imager and the flash lamps. Proper timing for the opening and closing of the shutters eliminates a direct interaction between the imager and flash lamps for a single sided measurement, enabling accurate measurement of the thermal response of a specimen. The time dependence of the thermal response is analyzed to produce an image of the effective diffusivity of the specimen. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winfree, WP (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 6 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 0-8194-4460-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4710 BP 536 EP 544 DI 10.1117/12.459604 PG 3 WC Engineering, Mechanical; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BU77V UT WOS:000176994600059 ER PT S AU Cramer, KE AF Cramer, KE BE Maldague, XP Rozlosnik, AE TI The inspection of high performance peltier coolers using lock-in thermography SO THERMOSENSE XXIV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Thermosense XXIV Conference CY APR 01-04, 2002 CL ORLANDO, FL SP SPIE DE infrared; thermal; NDE; lock-in thermogaphy AB Peltier cooling devices are used on the Hubble Space telescope for temperature control of various detector packages. A typical construction of these devices involves sandwiching an array of Bismuth-Tellurium (Bi2Te3) Posts between two ceramic plates. When a DC current is applied to the device heat is moved from one side of the device to the other, depending on the polarity of the current. Because these devices can change temperature very rapidly, there is the potential for damage due to thermal expansion and contraction of the constituents. A failure in the bonding of the Bi2Te3 to the ceramic sheet can lead to reduced efficiency or failure of the device. NASA Langley Research Center has developed a nondestructive thermal imaging technique to determine the integrity of the Bi2Te3 posts through the ceramic surface of the peltier device. By driving the peltier device with a time varying DC current, a corresponding temperature rise and fall can be observed on the surface of the device using a commercial infrared camera. Lock-in thermogaphy can then be used to construct both phase and amplitude images of the front surface temperature. It has been found that failure of Bi2Te3 posts results in a measurable change in both the amplitude and phase. This paper will describe an inspection method that has been developed and show results of the inspection of the extremely small Bi2Te3 posts whose dimensions are 0.81mm by 0.81mm. and approximately 1.45mm tall. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cramer, KE (reprint author), NASA, Langley Res Ctr, 4 Langley Blvd,Mail Stop 231, Hampton, VA 23681 USA. NR 8 TC 0 Z9 0 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 0-8194-4460-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4710 BP 545 EP 551 DI 10.1117/12.459605 PG 3 WC Engineering, Mechanical; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BU77V UT WOS:000176994600060 ER PT S AU Zalameda, JN Winfree, WP AF Zalameda, JN Winfree, WP BE Maldague, XP Rozlosnik, AE TI "Quantitative thermal nondestructive evaluation using an uncooled microbolometer infrared camera" SO THERMOSENSE XXIV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Thermosense XXIV Conference CY APR 01-04, 2002 CL ORLANDO, FL SP SPIE DE thermal nondestructive evaluation; electronic shutters; uncooled microbolometer infrared camera; and thermal diffusivity AB Recent advances in uncooled microbolometer detector arrays has resulted in low cost, small size/weight, and low power consumption infrared cameras. The purpose of this paper is to assess the capabilities of the new microbolometer infrared cameras for quantitative thermal nondestructive evaluation. The camera assessed is a 160 x 128 uncooled microbolometer sensor array operating in the long wavelength infrared band (7.5 to 13.5 microns). The camera size is 4.32 H x 4.32 W X 10.92 L centimeters. Quantitative thermal diffusivity and thickness images obtained by minimizing the squared difference between the data and a thermal model on samples with fabricated defects are presented. The results are compared to conventional thermal imaging cameras using cooled focal plane array detectors. The advantages of a synchronized electronic shutter system (SESS) to remove the heat lamp influence during and after flash heating will also be discussed for these uncooled microbolometer detector arrays. C1 NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch MS 231, USA Res Lab,Vehicle Technol Directorate, Hampton, VA 23681 USA. RP Zalameda, JN (reprint author), NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch MS 231, USA Res Lab,Vehicle Technol Directorate, Hampton, VA 23681 USA. NR 5 TC 4 Z9 4 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 0-8194-4460-X J9 P SOC PHOTO-OPT INS PY 2002 VL 4710 BP 610 EP 617 DI 10.1117/12.459614 PG 2 WC Engineering, Mechanical; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BU77V UT WOS:000176994600068 ER PT B AU Alvarez-Salazar, OS Balakrishnan, AV Iliff, KW AF Alvarez-Salazar, OS Balakrishnan, AV Iliff, KW BE Sivasundaram, S TI AFT: Aeroelastic flight test NASA - UCLA 1999 SO THIRD INTERNATIONAL CONFERENCE ON NONLINEAR PROBLEMS IN AVIATION AND AEROSPACE, VOLS 1 AND 2, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Nonlinear Problems in Aviation and Aerospace CY MAY 10-12, 2000 CL EMBRY RIDDLE AERONAUT UNIV, DAYTONA BEACH, FL SP Int Federat Nonlinear Analysts, Int Federat Informat Proc, Inst Elect & Elect Engineers Inc, Amer Inst Aeronaut & Astronaut HO EMBRY RIDDLE AERONAUT UNIV AB This paper is the first report on the first of a series of flight tests conducted at NASA Dryden Flight Research Center in a joint program with the Flight Systems Research Center, UCLA, to investigate subsonic/transonic aeroelastic phenomena, including Aeroelastic Flutter Boundary Expansion with self-straining actuators and Gust Monitoring and Alleviation. The flight articles - a long slender high-aspect ratio aluminum wing and a laser wind measurement device - are described as well as details on the first series of four flights. Noteworthy was a dynamic stall phenomenon encountered unexpectedly in the first flight. The flights generally achieved their purpose: verifying feasibility of such testing and faithfulness of Balakrishnan's subsonic wing flutter continuum mathematical models; and, demonstration of non-intrusive gust measurement on board. C1 Univ Calif Los Angeles, Flight Syst Res Ctr, Los Angeles, CA 90095 USA. NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. RP Alvarez-Salazar, OS (reprint author), Univ Calif Los Angeles, Flight Syst Res Ctr, Los Angeles, CA 90095 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN CONFERENCE PUBLICATIONS PI CAMBRIDGE CB4 4RT PA PO BOX 806 COTTENHAM, CAMBRIDGE CB4 4RT, ENGLAND BN 0-9526643-2-1 PY 2002 BP 31 EP 45 PG 15 WC Automation & Control Systems; Engineering, Aerospace; Mathematics, Applied SC Automation & Control Systems; Engineering; Mathematics GA BX15Z UT WOS:000184462700004 ER PT B AU Cao, W Burghart, J AF Cao, W Burghart, J BE Sivasundaram, S TI Mathematical foundation of necessary conditions for convergence of BP algorithm SO THIRD INTERNATIONAL CONFERENCE ON NONLINEAR PROBLEMS IN AVIATION AND AEROSPACE, VOLS 1 AND 2, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Nonlinear Problems in Aviation and Aerospace CY MAY 10-12, 2000 CL EMBRY RIDDLE AERONAUT UNIV, DAYTONA BEACH, FL SP Int Federat Nonlinear Analysts, Int Federat Informat Proc, Inst Elect & Elect Engineers Inc, Amer Inst Aeronaut & Astronaut HO EMBRY RIDDLE AERONAUT UNIV AB It is well known that the B.P. algorithm is not global convergent and on some occasions the training will end up at local minimum, which is indicated by the misclassifying the given pattern classification problem. Study of necessary conditions for convergence of B.P. algorithm is critical to understand the mechanism of "local minimum" and further answer the related open questions. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Cleveland, OH 44105 USA. RP Cao, W (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN CONFERENCE PUBLICATIONS PI CAMBRIDGE CB4 4RT PA PO BOX 806 COTTENHAM, CAMBRIDGE CB4 4RT, ENGLAND BN 0-9526643-2-1 PY 2002 BP 109 EP 115 PG 7 WC Automation & Control Systems; Engineering, Aerospace; Mathematics, Applied SC Automation & Control Systems; Engineering; Mathematics GA BX15Z UT WOS:000184462700013 ER PT B AU Oyama, A Obayashi, S Nakahashi, K Nakamura, T AF Oyama, A Obayashi, S Nakahashi, K Nakamura, T BE Sivasundaram, S TI Aerodynamic optimization of transonic wing design based on evolutionary algorithm SO THIRD INTERNATIONAL CONFERENCE ON NONLINEAR PROBLEMS IN AVIATION AND AEROSPACE, VOLS 1 AND 2, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Nonlinear Problems in Aviation and Aerospace CY MAY 10-12, 2000 CL EMBRY RIDDLE AERONAUT UNIV, DAYTONA BEACH, FL SP Int Federat Nonlinear Analysts, Int Federat Informat Proc, Inst Elect & Elect Engineers Inc, Amer Inst Aeronaut & Astronaut HO EMBRY RIDDLE AERONAUT UNIV DE optimization; evolutionary algorithm; CFD; wing; parallel computing ID ADJOINT FORMULATION; PARALLEL COMPUTERS; EQUATIONS; EULER AB Evolutionary Algorithm (EA) is applied to a practical three-dimensional shape optimization for aerodynamic design of an aircraft wing. Aerodynamic performances of the design candidates are evaluated by using the three-dimensional compressive Navier-Stokes equations. A structural constraint is introduced to avoid an apparent solution of zero thickness wing for low drag in high speeds. To overcome enormous computational time necessary for the optimization, the computation is parallelized on Numerical Wind Tunnel at National Aerospace Laboratory in Japan, a parallel computer with 166 vector-processing elements. The results ensure the capability of the EA in handling large-scale design optimizations. C1 NASA, Glenn Res Ctr, Prop Syst Technol Branch, Cleveland, OH 44135 USA. RP Oyama, A (reprint author), NASA, Glenn Res Ctr, Prop Syst Technol Branch, Cleveland, OH 44135 USA. NR 25 TC 0 Z9 0 U1 1 U2 1 PU EUROPEAN CONFERENCE PUBLICATIONS PI CAMBRIDGE CB4 4RT PA PO BOX 806 COTTENHAM, CAMBRIDGE CB4 4RT, ENGLAND BN 0-9526643-2-1 PY 2002 BP 537 EP 546 PG 10 WC Automation & Control Systems; Engineering, Aerospace; Mathematics, Applied SC Automation & Control Systems; Engineering; Mathematics GA BX15Z UT WOS:000184462700057 ER PT B AU Ravindran, SS AF Ravindran, SS BE Sivasundaram, S TI Active control of flow separation over an airfoil SO THIRD INTERNATIONAL CONFERENCE ON NONLINEAR PROBLEMS IN AVIATION AND AEROSPACE, VOLS 1 AND 2, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Nonlinear Problems in Aviation and Aerospace CY MAY 10-12, 2000 CL EMBRY RIDDLE AERONAUT UNIV, DAYTONA BEACH, FL SP Int Federat Nonlinear Analysts, Int Federat Informat Proc, Inst Elect & Elect Engineers Inc, Amer Inst Aeronaut & Astronaut HO EMBRY RIDDLE AERONAUT UNIV DE active control; flow separation; airfoil; compressible flow AB Designing an aircraft without conventional control surfaces is of interest to aerospace community. In this direction, smart actuator devices such as synthetic jets have been proposed to provide aircraft maneuverability instead of control surfaces. In this article, a numerical study is performed to investigate the effects of unsteady suction and blowing on airfoils. The unsteady suction and blowing is introduced at the leading edge of the airfoil in the form of tangential jet. Numerical solutions are obtained using Reynolds-averaged viscous compressible Navier-Stokes equations. Unsteady suction and blowing is investigated as a means of separation control to obtain lift on airfoils. The effect of blowing coefficients on lift and drag is investigated. The numerical simulations are compared with experiments from the Tel-Aviv University (TAU). These results indicate that unsteady suction and blowing can be used as a means of separation control to generate lift on airfoils. C1 NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. RP Ravindran, SS (reprint author), NASA, Langley Res Ctr, Flow Phys & Control Branch, Hampton, VA 23681 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN CONFERENCE PUBLICATIONS PI CAMBRIDGE CB4 4RT PA PO BOX 806 COTTENHAM, CAMBRIDGE CB4 4RT, ENGLAND BN 0-9526643-2-1 PY 2002 BP 569 EP 578 PG 10 WC Automation & Control Systems; Engineering, Aerospace; Mathematics, Applied SC Automation & Control Systems; Engineering; Mathematics GA BX15Z UT WOS:000184462700060 ER PT B AU Zhou, J Lau, WKM Laughlin, LW Masuoka, PM Andre, RC Chamberlin, J AF Zhou, J Lau, WKM Laughlin, LW Masuoka, PM Andre, RC Chamberlin, J GP AMS AMS TI The effect of regional climate variability on outbreak of epidemics of bartonellosis in Peru SO THIRD SYMPOSIUM ON ENVIRONMENTAL APPLICATIONS: FACILITATING THE USE OF ENVIRONMENTAL INFORMATION LA English DT Proceedings Paper CT 3rd Symposium on Environmental Applications CY JAN 13-17, 2002 CL ORLANDO, FL SP Amer Meteorol Soc ID PRECIPITATION C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zhou, J (reprint author), NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 7 TC 1 Z9 1 U1 0 U2 1 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2002 BP 123 EP 126 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA BV55D UT WOS:000179335500023 ER PT S AU Lowry, MR AF Lowry, MR BE Katoen, JP Stevens, P TI Software construction and analysis tools for future space missions SO TOOLS AND ALGORITHMS FOR THE CONSTRUCTION AND ANAYLSIS OF SYSTEMS, PROCEEDINGS SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 8th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS 2002) CY APR 08-12, 2002 CL GRENOBLE, FRANCE SP Lab Verimag AB NASA and its international partners will increasingly depend on software-based systems to implement advanced functions for future space missions, such as Martian rovers that autonomously navigate long distances exploring geographic features formed by surface water early in the planet's history. The software-based functions for these missions will need to be robust and highly reliable, raising significant challenges in the context of recent Mars mission failures attributed to software faults. After reviewing these challenges, this paper describes tools that have been developed at NASA Ames that could contribute to meeting these challenges: 1) Program synthesis tools based on automated inference that generate documentation for manual review and annotations for automated certification. 2) Model-checking tools for concurrent object-oriented software that achieve scalability through synergy with program abstraction and static analysis tools. C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94303 USA. RP Lowry, MR (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94303 USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-43419-4 J9 LECT NOTES COMPUT SC PY 2002 VL 2280 BP 1 EP 19 PG 19 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BW19F UT WOS:000181139900001 ER PT S AU Havelund, K Rosu, G AF Havelund, K Rosu, G BE Katoen, JP Stevens, P TI Synthesizing monitors for safety properties SO TOOLS AND ALGORITHMS FOR THE CONSTRUCTION AND ANAYLSIS OF SYSTEMS, PROCEEDINGS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 8th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS 2002) CY APR 08-12, 2002 CL GRENOBLE, FRANCE SP Lab Verimag ID JAVA PROGRAMS AB The problem of testing a linear temporal logic (LTL) formula on a finite execution trace of events, generated by an executing program, occurs naturally in runtime analysis of software. An algorithm which takes a past time LTL formula and generates an efficient dynamic programming algorithm is presented. The generated algorithm tests whether the formula is satisfied by a finite trace of events given as input and runs in linear time, its constant depending on the size of the LTL formula. The memory needed is constant, also depending on the size of the formula. Further optimizations of the algorithm are suggested. Past time operators suitable for writing succinct specifications are introduced and shown definitionally equivalent to the standard operators. This work is part of the PathExployer project, the objective of which it is to construct a flexible framework for monitoring and analyzing program executions. C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Automated Software Engn Grp, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. NR 19 TC 80 Z9 81 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-43419-4 J9 LECT NOTES COMPUT SC PY 2002 VL 2280 BP 342 EP 356 PG 15 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BW19F UT WOS:000181139900023 ER PT B AU Furusho, T AF Furusho, T BE Borgani, S Mezzetti, M Valdarnini, R TI ASCA study of dynamical evolution in nearby clusters SO TRACING COSMIC EVOLUTION WITH GALAXY CLUSTERS, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Tracing Cosmic Evolution with Galaxy Clusters CY JUL 03-06, 2001 CL SESTO PUSTERIA, ITALY SP Univ Trieste, Dept Astron, Int Sch Adv Studies, Natl Inst Astrophys ID CENTAURUS-CLUSTER; TEMPERATURE MAP; GALAXIES; ABELL-1060; AWM-7 AB We examine the constraint on the cluster evolution based on the temperature structure combined with the metallicity distribution in 6 nearby clusters of galaxies. Remarkable hot regions in many clusters demonstrate the clusters have undergone strong mergers. Significant gradients of the metallicity profiles found in several systems are shown to trace the galaxy distribution, which suggests that the gas was not substantially mixed after the metal injection period. Combination of the temperature and metallicity distributions enables us to estimate the time history of metal injection, major merger, and quiet periods. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Furusho, T (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. 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 BN 1-58381-108-7 J9 ASTR SOC P PY 2002 VL 268 BP 369 EP 370 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BV27L UT WOS:000178406700073 ER PT S AU Krotkov, N Herman, J Bhartia, PK Seftor, C Arola, A Kaurola, J Koskinen, L Kalliskota, S Taalas, P Geogdzhaev, I AF Krotkov, N Herman, J Bhartia, PK Seftor, C Arola, A Kaurola, J Koskinen, L Kalliskota, S Taalas, P Geogdzhaev, I BE Slusser, JR Herman, JR Gao, W TI Version 2 TOMS UV algorithm: problems and enhancements SO ULTRAVIOLET GROUND- AND SPACE-BASED MEASUREMENTS, MODELS, AND EFFECTS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet Ground- and Space-based Measurements, Models, and Effects CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE, NASA Langley Res Ctr, USDA, UV B Monitoring & Res Program, NASA Goddard Space Flight Ctr, Earth Probe TOMS Program DE UV irradiance; radiative transfer models; aerosols; clouds; snow albedo ID ACTIVE ULTRAVIOLET-RADIATION; TOTAL OZONE; SURFACE UV; EARTHS SURFACE; ATMOSPHERIC TRANSMISSION; SATELLITE ESTIMATION; SOLAR UV; AEROSOLS; IRRADIANCE; CLOUDS AB Satellite instruments currently provide global maps of surface UV irradiance by combining backscattered radiance measurements with radiative transfer models. The models are often limited by uncertainties in physical input parameters of the atmosphere and the surface. We evaluate the effects of possible enhancements of the current TOMS surface UV irradiance algorithm. The major enhancements include more detailed treatment of tropospheric aerosols, effects of diurnal variation of cloudiness and improved treatment of snow/ice. The emphasis is on the comparison between the results of the current (version 1) TOMS UV algorithm and each of the changes proposed. Currently, TOMS UV reflectivity data are used to correct for non-absorbing aerosols and clouds. Absorbing aerosols are detected and corrected by using the TOMS aerosol index (AI) data. Since the AI technique does not have the sensitivity to detect weakly absorbing aerosols close to the ground the treatment of aerosol attenuation of UV irradiance might have been improved by using newly derived TOMS products: optical depths and the single-scattering albedo for dust, smoke, and sulfate aerosols. We evaluate different approaches for improved treatment of pixel average cloud attenuation, with and without snow/ice on the ground. In addition to treating clouds based only on the measurements at the local time of the TOMS observations, the results from other satellites and weather assimilation models can be used to estimate attenuation of the incident UV irradiance throughout the day. The improved (version 2) algorithm will be applied to re-process the existing TOMS UV data record (since 1978) and to the future satellite sensors (e.g., Quik/TOMS, GOME, OMI on EOS/Aura and Triana/EPIC). C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, Greenbelt, MD 20771 USA. RP Krotkov, N (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, Code 916, Greenbelt, MD 20771 USA. RI Krotkov, Nickolay/E-1541-2012; Bhartia, Pawan/A-4209-2016; OI Krotkov, Nickolay/0000-0001-6170-6750; Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632; Arola, Antti/0000-0002-9220-0194 NR 69 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 0-8194-4196-1 J9 P SOC PHOTO-OPT INS PY 2002 VL 4482 BP 82 EP 93 AR UNSP 4482-09 DI 10.1117/12.452956 PG 12 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing SC Engineering; Instruments & Instrumentation; Remote Sensing GA BU15F UT WOS:000175162200008 ER PT S AU Grant, WB AF Grant, WB BE Slusser, JR Herman, JR Gao, W TI Health benefits of solar UV-B radiation: Cancer risk reduction SO ULTRAVIOLET GROUND- AND SPACE-BASED MEASUREMENTS, MODELS, AND EFFECTS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultraviolet Ground- and Space-based Measurements, Models, and Effects CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE, NASA Langley Res Ctr, USDA, UV B Monitoring & Res Program, NASA Goddard Space Flight Ctr, Earth Probe TOMS Program ID CUTANEOUS MALIGNANT-MELANOMA; NON-HODGKINS-LYMPHOMA; VITAMIN-D-RECEPTOR; PROSTATE-CANCER; BREAST-CANCER; ULTRAVIOLET-RADIATION; UNITED-STATES; SERUM LEVELS; HUMAN SKIN; MORTALITY AB Based on geographical distributions of various cancers in the U.S. and elsewhere, ecologic studies comparing these distributions to indices of solar radiation during the past 20 years have led to the understanding that solar UV-B radiation is a risk reduction factor for breast, colon, ovarian, prostate cancer and non-Hodgkin's lymphoma (NHL). Photo-initiated production of vitamin D is the mechanism that enables solar UV-B to play this role. The work presented here explores the use of the USDA UVB Radiation Monitoring Program ground station values to confirm and extend the prior results, and compares these results to those obtained using UV-B data from the Total Ozone Mapping Spectrometer (TOMS). Inverse correlations between solar UV-B radiation have been found for a total of 14 cancers using mortality data from the U.S. with these data sets, and are supported by additional studies using cancer mortality and dietary supply data from Europe. While vitamin D has been shown to be a risk reduction factor for several of these cancers, it is hoped that additional studies will be conducted to confirm or disprove the protective role of UV-B and/or vitamin D for the remaining cancers. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Grant, WB (reprint author), 12 Sir Francis Wyatt Pl, Newport News, VA 23606 USA. OI Grant, William/0000-0002-1439-3285 NR 40 TC 8 Z9 8 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 0-8194-4196-1 J9 P SOC PHOTO-OPT INS PY 2002 VL 4482 BP 324 EP 334 AR UNSP 4482-40 DI 10.1117/12.452935 PG 11 WC Engineering, Aerospace; Instruments & Instrumentation; Remote Sensing SC Engineering; Instruments & Instrumentation; Remote Sensing GA BU15F UT WOS:000175162200034 ER PT S AU Floyd, SR Sheppard, DA Odom, JL Dantzler, AA Murphy, SD AF Floyd, SR Sheppard, DA Odom, JL Dantzler, AA Murphy, SD BE Trombka, JI Spears, DP Solomon, PH TI The analog system for the Gamma Ray Spectrometer on Mars Odyssey SO UNATTENDED RADIATION SENSOR SYSTEMS FOR REMOTE APPLICATIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Unattended Radiation Sensor Systems for Remote Applications CY APR 15-17, 2002 CL WASHINGTON, D.C. SP NASA, Headquarters, NASA, Goddard Space Flight Ctr, USDE, US Dept Justice, US State, Nonproliferat & Arms Control Technol Working Grp AB The Gamma Ray Spectrometer instrument on board the Mars Odyssey spacecraft was powered up for the second time since launch in April 2001. High voltage was applied to the Ge detector in February 2002. The system is performing well, but the detector is showing resolution degradation from solar particles and cosmic ray exposure during the long cruise. The analog system and high voltage part of the system were designed and built at NASA's Goddard Space Flight Center. This portion of the instrument system will be presented. Of the many design challenges, three stand out on this mission. The prohibited materials and elemental mass budget for everything used in the construction was defined and constrained. This type of constraint was unique and challenging. Signal overload recovery from cosmic ray and high-energy solar proton hits was a challenge because the environment could not be well defined and varies throughout the Sun cycle: The design effort to prevent microphonic problems in the very sensitive front-end electronics was a challenge because the building of the instrument preceded the spacecraft. The mechanical noise environment from reaction wheels and other mechanisms on the yet to be built and tested spacecraft was based on judgement and analysis. The analog system design and performance data will be discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Floyd, SR (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. NR 1 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 0-7354-0087-3 J9 AIP CONF PROC PY 2002 VL 632 BP 135 EP 141 PG 7 WC Astronomy & Astrophysics; Remote Sensing SC Astronomy & Astrophysics; Remote Sensing GA BV40F UT WOS:000178846200013 ER PT S AU McClanahan, TP Trombka, JI Floyd, SR Truskowski, W Starr, RD Clark, PE Evans, LG AF McClanahan, TP Trombka, JI Floyd, SR Truskowski, W Starr, RD Clark, PE Evans, LG BE Trombka, JI Spears, DP Solomon, PH TI A ground systems template for remote sensing systems SO UNATTENDED RADIATION SENSOR SYSTEMS FOR REMOTE APPLICATIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Unattended Radiation Sensor Systems for Remote Applications CY APR 15-17, 2002 CL WASHINGTON, D.C. SP NASA, Headquarters, NASA, Goddard Space Flight Ctr, USDE, US Dept Justice, US State, Nonproliferat & Arms Control Technol Working Grp ID GAMMA-RAY SPECTROMETER AB Spaceborne remote sensing using gamma and X-ray spectrometers requires particular attention to the design and development of reliable systems. These systems must ensure the scientific requirements of the mission within the challenging technical constraints of, operating instrumentation in space. The Near Earth Asteroid Rendezvous (NEAR) spacecraft included X-ray and gamma-ray spectrometers (XGRS), whose mission was to map the elemental chemistry of the 433 Eros asteroid. A remote sensing system template, similar to a blackboard systems approach used in artificial intelligence, was identified in which the spacecraft, instrument, and ground system was designed and developed to monitor and adapt to evolving mission requirements in a complicated operational setting. Systems were developed for ground tracking of instrument calibration, instrument health, data quality, orbital geometry, solar flux as well as models of the asteroid's surface characteristics, requiring an intensive human effort. In the future, missions such as the Autonomous Nano-Technology Swarm (ANTS) program will have to rely heavily on automation to collectively encounter and sample asteroids in the outer asteroid belt. Using similar instrumentation, ANTS will require information similar to data collected by the NEAR X-ray/Gamma-Ray Spectrometer (XGRS) ground system for science and operations management. The NEAR XGRS systems will be studied to identify the equivalent subsystems that may be automated for ANTS: The effort will also investigate the possibility of applying blackboard style approaches to automated decision making required for ANTS. C1 NASA, Goddard Space Flight Ctr, AstroChem Branch, Greenbelt, MD 20771 USA. RP McClanahan, TP (reprint author), NASA, Goddard Space Flight Ctr, AstroChem Branch, Code 661, Greenbelt, MD 20771 USA. 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 0-7354-0087-3 J9 AIP CONF PROC PY 2002 VL 632 BP 158 EP 164 PG 7 WC Astronomy & Astrophysics; Remote Sensing SC Astronomy & Astrophysics; Remote Sensing GA BV40F UT WOS:000178846200016 ER PT S AU Trombka, J McClanahan, T Floyd, S AF Trombka, J McClanahan, T Floyd, S BE Trombka, JI Spears, DP Solomon, PH TI Infrastructure needs to support unattended and remote detector systems SO UNATTENDED RADIATION SENSOR SYSTEMS FOR REMOTE APPLICATIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Unattended Radiation Sensor Systems for Remote Applications CY APR 15-17, 2002 CL WASHINGTON, D.C. SP NASA, Headquarters, NASA, Goddard Space Flight Ctr, USDE, US Dept Justice, US State, Nonproliferat & Arms Control Technol Working Grp ID RAY SPECTROMETER; X-RAY AB The use of unattended and remote detection systems for use in telemedicine, teleforensics and applications to operations in homeland security and nuclear non proliferation programs will require the development of portable detector systems and public information network systems. With the availability of such networks, the deployment of relatively inexpensive sensor systems can be achieved. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Trombka, J (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 691, Greenbelt, MD 20771 USA. RI McClanahan, Timothy/C-8164-2012 NR 6 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 0-7354-0087-3 J9 AIP CONF PROC PY 2002 VL 632 BP 227 EP 234 PG 8 WC Astronomy & Astrophysics; Remote Sensing SC Astronomy & Astrophysics; Remote Sensing GA BV40F UT WOS:000178846200025 ER PT S AU Mexcur, P Kalshoven, J AF Mexcur, P Kalshoven, J BE Trombka, JI Spears, DP Solomon, PH TI Tapping into a billion dollar resource, SBIR/STTR SO UNATTENDED RADIATION SENSOR SYSTEMS FOR REMOTE APPLICATIONS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Unattended Radiation Sensor Systems for Remote Applications CY APR 15-17, 2002 CL WASHINGTON, D.C. SP NASA, Headquarters, NASA, Goddard Space Flight Ctr, USDE, US Dept Justice, US State, Nonproliferat & Arms Control Technol Working Grp AB This presentation provides an overview of the Small Business Innovation Research (SBIR) and the Small Business Technology Transfer (STTR) Programs as implemented by the National Aeronautics and Space Administration (NASA). These programs, as mandated by Congress, provide an opportunity for small, high technology companies and research institutions to participate in Government sponsored research and development (R&D) efforts in key technology areas. This presentation describes the background and operation of these two programs and discusses what factors a business should consider in making the decision to participate. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mexcur, P (reprint author), NASA, Goddard Space Flight Ctr, 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 0-7354-0087-3 J9 AIP CONF PROC PY 2002 VL 632 BP 263 EP 265 PG 3 WC Astronomy & Astrophysics; Remote Sensing SC Astronomy & Astrophysics; Remote Sensing GA BV40F UT WOS:000178846200029 ER PT S AU Wilcox, BH AF Wilcox, BH BE Gerhart, GR Shoemaker, CM Gage, DW TI Sinkage and slippage estimation for an articulated vehicle SO UNMANNED GROUND VEHICLE TECHNOLOGY IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology IV CY APR 02-03, 2002 CL ORLANDO, FL SP SPIE DE robotic vehicles; sinkage; slippage AB This paper describes an approach to estimating in real-time the degree to which an articulated robotic vehicle is undergoing wheel slip and/or sinkage in soft terrain. Robotic vehicles generally have hazard avoidance sensors which measure the shape of the sensible surface, and these can be used to predict what the articulation pose of the vehicle will be as it moves over the surface. An articulated vehicle (one with more than two wheels on each side) can directly measure the shape of the loadbearing surface by combining inclination and articulation sensing. Delays between the actual articulations and the expectations can be explained by wheel slippage. Differences between the expectation and the actual articulations can be explained by sink-age below the sensed surface. If one assumes that successive wheels on each side follow the same profile as the front wheel (sinking the same amount, if any, into the soil), then it is possible to estimate sinkage and slippage separately. A Maximum-A-Posteriori estimation procedure formalizing this heuristic approach is developed and simulated, and the results presented and discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Wilcox, BH (reprint author), 4800 Oak Grove Dr MS 107-102, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 1 U1 0 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 0-8194-4465-0 J9 P SOC PHOTO-OPT INS PY 2002 VL 4715 BP 267 EP 274 DI 10.1117/12.474458 PG 8 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BV18D UT WOS:000178075300028 ER PT S AU Ning, CZ AF Ning, CZ BE Lei, C Kilcoyne, SP TI Ultrafast narrow bandwidth modulation of VCSELs SO VERTICAL-CAVITY SURFACE-EMITTING LASERS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Vertical-Cavity Surface-Emitting Lasers VI CY JAN 23-24, 2002 CL SAN JOSE, CA SP SPIE DE ultrafast modulation; VCSELs; microwave photonics; millimeter wave photonics; transverse mode dynamics AB Ultrafast modulation of semiconductor lasers at a rate higher than the relaxation-oscillation limited frequency is important for millimeter wave photonics and many other applications. Edge-emitters of compound cavities and other multi-section devices have been employed for such generation in the past. We demonstrate in this paper two. methods of modulating VCSELs in the frequency range between 20GHz and 130GHz through a detailed numerical simulation. The first method employs two coupled VCSELs and high frequency oscillation is provided by inter-VCSEL coupling, while the second method utilizes multi-transverse mode beating in a large VCSEL. We show that the mode beating is greatly enhanced by collecting laser output from part of the output facet, providing a relatively easy laser modulation at a frequency larger than 100GHz. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ning, CZ (reprint author), NASA, Ames Res Ctr, MS-T27A-1, Moffett Field, CA 94035 USA. NR 17 TC 0 Z9 0 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 0-8194-4388-3 J9 P SOC PHOTO-OPT INS PY 2002 VL 4649 BP 236 EP 244 DI 10.1117/12.469239 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU98J UT WOS:000177553700028 ER PT S AU McGlynn, T Suchkov, A Winter, E Angelini, L Corcoran, MF Derriere, S Donahue, M Drake, S Fernique, P Genova, F Hanisch, R Ochsenbein, F Pence, W Postman, M White, N White, R AF McGlynn, T Suchkov, A Winter, E Angelini, L Corcoran, MF Derriere, S Donahue, M Drake, S Fernique, P Genova, F Hanisch, R Ochsenbein, F Pence, W Postman, M White, N White, R BE Szalay, AS TI Classifying the high energy universe with ClassX SO VIRTUAL OBSERVATORIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Virtual Observatories CY AUG 25-26, 2002 CL WAIKOLOA, HI SP SPIE, Int Commiss Opt, Amer Astron Soc, European SO Observ, Int Astron Union DE Virtual Observatory; classification; high-energy astronomy AB Building an automated classifier for high-energy sources provides an opportunity to prototype approaches to building the Virtual Observatory with a substantial immediate scientific return. The ClassX collaboration is combining existing data resources with trainable classifiers to build a tool that classifies lists of objects presented to it. In our first year the collaboration has concentrated on developing pipeline software that finds and combines information of interest and in exploring the issues that will be needed for successful classification. ClassX must deal with many key VO issues: automating access to remote data resources, combining heterogeneous data and dealing with large data volumes. While the VO must attempt to deal with these problems in a generic way, the clear science goals of ClassX allow us to act as a pathfinder exploring particular approaches to addressing these issues. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Sci Arch Res Ctr, Greenbelt, MD 20771 USA. RP McGlynn, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Sci Arch Res Ctr, Greenbelt, MD 20771 USA. RI White, Nicholas/B-6428-2012; OI White, Nicholas/0000-0003-3853-3462; Genova, Francoise/0000-0002-6318-5028 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 0-8194-4625-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4846 BP 43 EP 52 DI 10.1117/12.459719 PG 10 WC Astronomy & Astrophysics; Computer Science, Information Systems; Imaging Science & Photographic Technology SC Astronomy & Astrophysics; Computer Science; Imaging Science & Photographic Technology GA BV96X UT WOS:000180549000007 ER PT S AU Jacob, JC Brunner, R Curkendall, DW Djorgovski, SG Good, JC Husman, L Kremenek, G Mahabal, A AF Jacob, JC Brunner, R Curkendall, DW Djorgovski, SG Good, JC Husman, L Kremenek, G Mahabal, A BE Szalay, AS TI yourSky: Rapid desktop access to custom astronomical image mosaics SO VIRTUAL OBSERVATORIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Virtual Observatories CY AUG 25-26, 2002 CL WAIKOLOA, HI SP SPIE, Int Commiss Opt, Amer Astron Soc, European SO Observ, Int Astron Union DE astronomical image mosaics; web portal; image reprojection; data access AB The yourSky custom astronomical image mosaicking software has a Web portal architecture that allows access via ordinary desktop computers with low bandwidth network connections to high performance and highly customizable mosaicking software deployed in a high performance computing and communications environment. The emphasis is on custom access to image mosaics constructed from terabytes of raw image data stored in remote archives. In this context, custom access refers to new technology that enables on the fly mosaicking to meet user-specified criteria for region of the sky to be mosaicked, datasets to be used, resolution, coordinate system, projection, data type and image format. The yourSky server is a fully automated end-to-end system that handles all aspects of the mosaic construction. This includes management of mosaic requests, determining which input images are required to fulfill each request, management of a data cache for both input image plates and output mosaics, retrieval of input image plates from massive remote archives, image mosaic construction on a multiprocessor system, and making the result accessible to the user on the desktop. The URL for yourSky is http://yourSky.jpl.nasa.gov. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jacob, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 126-104, Pasadena, CA 91109 USA. NR 8 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 0-8194-4625-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4846 BP 53 EP 64 DI 10.1117/12.461514 PG 12 WC Astronomy & Astrophysics; Computer Science, Information Systems; Imaging Science & Photographic Technology SC Astronomy & Astrophysics; Computer Science; Imaging Science & Photographic Technology GA BV96X UT WOS:000180549000008 ER PT S AU Pence, WD McGlynn, T Chai, P Heikkila, C AF Pence, WD McGlynn, T Chai, P Heikkila, C BE Szalay, AS TI Hera: The HEASARC web based data analysis environment SO VIRTUAL OBSERVATORIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Virtual Observatories CY AUG 25-26, 2002 CL WAIKOLOA, HI SP SPIE, Int Commiss Opt, Amer Astron Soc, European SO Observ, Int Astron Union DE virtual observatory; high-energy astronomy AB Hera is a new experiment at the HEASARC (High Energy Astrophysics Science Archive Research Center) at the NASA Goddard Space Flight Center to provide a complete data analysis environment over the Internet for archival researchers. This new facility complements the existing Browse database search facility that is available on the Web. With Hera, users can search the HEASARC data archives with a Web browser and save any selected data set to their Hera disk space area. This only takes a few seconds compared to the many minutes or hours that it could take to down load large data sets to the user's local machine. The user can then immediately log into one of the available Hera server machines and begin analyzing the data without having to install any local software except for a very small Hera client application program that runs on the user's local machine. Hera is currently most useful for expert users who are already familiar with analyzing high energy data sets with the HEASARC software. In the future we intend to make Hera more useful for the novice scientific user by providing more on-line help features to guide the user through the data analysis process. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Sci Arch Res Ctr, Greenbelt, MD 20771 USA. RP Pence, WD (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Sci Arch Res Ctr, Greenbelt, MD 20771 USA. NR 0 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 0-8194-4625-4 J9 P SOC PHOTO-OPT INS PY 2002 VL 4846 BP 77 EP 80 DI 10.1117/12.461510 PG 4 WC Astronomy & Astrophysics; Computer Science, Information Systems; Imaging Science & Photographic Technology SC Astronomy & Astrophysics; Computer Science; Imaging Science & Photographic Technology GA BV96X UT WOS:000180549000010 ER PT B AU Shirah, GW Mitchell, HG AF Shirah, GW Mitchell, HG BE Moorhead, R Gross, M Joy, K TI NASA's great zooms: A case study SO VIS 2002: IEEE VISUALIZATION 2002, PROCEEDINGS LA English DT Proceedings Paper CT IEEE Visualization 2002 Conference CY OCT 30-NOV 01, 2002 CL BOSTON, MA SP IEEE Comp Soc Tech Comm Visualizat & Graph, ACM SIGRAPH, IEEE Comp Soc, Inst Elect & Electr Engn DE visualization; remote sensing; renderman; shader; georegistration; color matching AB This paper examines a series of NASA outreach visualizations created using several layers of remote sensing satellite data ranging from 4-kilometers per pixel to 1-meter per pixel. The viewer is taken on a seamless, cloud free journey from a global view of the Earth down to ground level where buildings, streets, and cars are visible. The visualizations were produced using a procedural shader that takes advantage of accurate georegistration and color matching between images. The shader accurately and efficiently maps the data sets to geometry allowing for animations with few perceptual transitions among data sets. We developed a pipeline to facilitate the production of over twenty zoom visualizations. Millions of people have seen these visualizations through national and international media coverage. C1 NASA, Goddard Space Flight Ctr, Sci Visualizat Studio, Greenbelt, MD 20771 USA. RP Shirah, GW (reprint author), NASA, Goddard Space Flight Ctr, Sci Visualizat Studio, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7498-3 PY 2002 BP 541 EP 544 PG 4 WC Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BV57S UT WOS:000179397800073 ER PT S AU Gross, RS Marcus, SL Dickey, JO AF Gross, RS Marcus, SL Dickey, JO BE Adam, J Schwarz, KP TI Modulation of the seasonal cycle in length-of-day and atmospheric angular momentum SO VISTAS FOR GEODESY IN THE NEW MILLENNIUM SE INTERNATIONAL ASSOCIATION OF GEODESY SYMPOSIA LA English DT Proceedings Paper CT Scientific Assembly of the International-Association-of-Geodesy CY SEP 02-07, 2001 CL BUDAPEST, HUNGARY SP Int Assoc Geodesy, Hungarian Acad Sci, European Space Agcy, NASA, Jet Prop Lab, Budapest Univ Technol & Econ, Eotvos Lorand Geophys Inst, Hungarian Sci Res Fund, Minist Educ DE earth rotation; atmospheric angular momentum; El Nino; southern oscillation ID EARTH ROTATION; BUDGET; FLUCTUATIONS AB Global warming, by definition, changes the atmospheric temperature field. This temperature change is not expected to be uniform, either geographically, or with height in the atmosphere. By the thermal wind equation, changes in the pole-to-equator temperature gradient will cause changes in the atmospheric zonal winds. Numerous previous studies have shown that observed length-of-day (LOD) variations on time scales of a few days to a few years are largely caused by atmospheric zonal wind fluctuations. In particular, seasonal variations in LOD have been previously shown to be dominantly caused by seasonal variations in the atmospheric zonal winds. Here, observed changes in the strength of seasonal LOD and wind-driven atmospheric angular momentum signals during 1962 to 2000 are analyzed and shown to be significantly correlated with each other and with the Southern Oscillation Index. This demonstrates that the observed seasonal LOD signal can be used as a proxy measurement for changes in the angular momentum of the seasonal zonal winds, thereby allowing changes in the seasonal zonal winds to be studied even when wind measurements are not available. In addition, the approach of studying decadal-scale changes in the strength of the seasonal cycle allows LOD measurements to be used in climate change studies, studies that cannot be undertaken directly due to uncertainties in modeling the dominant decadal-scale changes in LOD caused by core-mantle boundary processes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gross, RS (reprint author), CALTECH, Jet Prop Lab, Mail Stop 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Symposia, IAG/K-2857-2012 NR 27 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0939-9585 BN 3-540-43454-2 J9 IAG SYMP PY 2002 VL 125 BP 457 EP 462 PG 6 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BV36J UT WOS:000178709100076 ER PT S AU Dickey, JO AF Dickey, JO BE Adam, J Schwarz, KP TI Interdisciplinary space geodesy: Challenges in the new millennium SO VISTAS FOR GEODESY IN THE NEW MILLENNIUM SE International Association of Geodesy Symposia LA English DT Proceedings Paper CT Scientific Assembly of the International-Association-of-Geodesy CY SEP 02-07, 2001 CL BUDAPEST, HUNGARY SP Int Assoc Geodesy, Hungarian Acad Sci, European Space Agcy, NASA, Jet Prop Lab, Budapest Univ Technol & Econ, Eotvos Lorand Geophys Inst, Hungarian Sci Res Fund, Minist Educ DE space geodesy; gravitational field; temporal variations of the potential; sea level and glaciology; ocean dynamics; ocean-bottom pressure; hydrology and water storage ID GRAVITY-FIELD AB The sphere of influence of space geodesy is ever enlarging, with impressive achievements in the last few decades in many diverse areas (such as geodynamics, planetary and atmospheric sciences, oceanography, tectonics, and ice studies). Earth system studies have made major advances with the advent of accurate space geodetic techniques with high temporal resolution and the increasing availability of complementary geophysical data. Examples include positioning at the millimeter level, enabling determination of crustal deformation and strain with unprecedented accuracy at high time resolution; water vapor monitoring via GPS; and improved gravity modeling and orbit determination, permitting an unparalleled view of the 1997-1998 ENSO event. The new millennium holds even more promise, with many planned developments, such as GOCE, GRACE, and ICESAT missions, densification of GPS networks, and the development of new technologies. This paper will highlight recent geodetic advances and their interdisciplinary impact with a vision towards the future. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jean.o.dickey@jpl.nasa.gov RI Symposia, IAG/K-2857-2012 NR 7 TC 1 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0939-9585 BN 3-540-43454-2 J9 IAG SYMP PY 2002 VL 125 BP 590 EP 594 PG 5 WC Geosciences, Multidisciplinary; Remote Sensing SC Geology; Remote Sensing GA BV36J UT WOS:000178709100099 ER PT S AU Jobson, DJ Rahman, ZU Woodell, GA AF Jobson, DJ Rahman, ZU Woodell, GA BE Rahman, ZU Schowengerdt, RA Reichenbach, SE TI The statistics of visual representation SO VISUAL INFORMATION PROCESSING XI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Visual Information Processing XI CY APR 04, 2002 CL ORLANDO, FL SP SPIE ID RETINEX; COLOR AB The experience of retinex image processing has prompted us to reconsider fundamental aspects of imaging and image processing. Foremost is the idea that a good visual representation requires a non-linear transformation of the recorded (approximately linear) image data. Further, this transformation appears to converge on a specific distribution. Here we investigate the connection between numerical and visual phenomena. Specifically the questions explored are: (1) Is there a well-defined consistent statistical character associated with good visual representations? (2) Does there exist an ideal visual image? And (3) what are its statistical properties?. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Jobson, DJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 6 TC 49 Z9 57 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 0-8194-4486-3 J9 P SOC PHOTO-OPT INS PY 2002 VL 4736 BP 25 EP 35 DI 10.1117/12.477589 PG 11 WC Computer Science, Artificial Intelligence; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BV20Q UT WOS:000178157800004 ER PT S AU Kiely, AB Klimesh, MA AF Kiely, AB Klimesh, MA BE Rahman, ZU Schowengerdt, RA Reichenbach, SE TI An adaptable recursive binary entropy coding technique SO VISUAL INFORMATION PROCESSING XI SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Visual Information Processing XI CY APR 04, 2002 CL ORLANDO, FL SP SPIE DE data compression; binary adaptive coding; recursive interleaved entropy coding ID DATA-COMPRESSION AB We present a novel data compression technique, called recursive interleaved entropy coding, that is based on recursive interleaving of variable-to-variable length binary source codes. A compression module implementing this technique has the same functionality as arithmetic coding and can be used as the "engine" in various data compression algorithms. The encoder compresses a bit sequence by recursively encoding groups of bits that have similar estimated statistics, ordering the output in a way that is suited to the decoder. As a result, the decoder has low complexity. The encoding process for our technique is adaptable in that each bit to be encoded has an associated probability-of-zero estimate that may depend on previously encoded bits; this adaptability allows more effective compression. Recursive interleaved entropy coding may have advantages over arithmetic coding, including most notably the admission of a simple and fast decoder. Much variation is possible in the choice of component codes and in the interleaving structure, yielding coder designs of varying complexity and compression efficiency; coder designs that achieve arbitrarily small redundancy can be produced. We discuss coder design and performance estimation methods. We present practical encoding and decoding algorithms, as well as measured performance results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 238-420, Pasadena, CA 91109 USA. EM aaron@shannon.jpl.nasa.gov; klimesh@shannon.jpl.nasa.gov NR 15 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 0-8194-4486-3 J9 PROC SPIE PY 2002 VL 4736 BP 151 EP 165 DI 10.1117/12.477575 PG 15 WC Computer Science, Artificial Intelligence; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BV20Q UT WOS:000178157800017 ER PT S AU Okino, CM Corr, MG AF Okino, CM Corr, MG GP IEEE IEEE TI Statistically accurate sensor networking SO WCNC 2002: IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE RECORD, VOLS 1 & 2 SE IEEE Wireless Communications and Networking Conference LA English DT Proceedings Paper CT IEEE Wireless Communications and Networking Conference CY MAR 17-21, 2002 CL ORLANDO, FL SP IEEE, IEEE COMMUN SOC, CTIA AB In this paper, we propose an alternate approach to ad-hoc networking called Best Effort multi-Hop Geographical Routing (BEHGR). BEHGR does not fit under the current classifications of on-demand or table-based approaches to ad-hoc routing, but instead statistically attempts to dynamically route packets to a central location in a "best effort" manner. The basis of such a protocol assumes that a sufficient measure of the performance of the network is a statistically accurate representation of the overall collected sensor data. The metrics representing the performance include the concept of currentness. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Okino, CM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1525-3511 BN 0-7803-7376-6 J9 IEEE WCNC PY 2002 BP 363 EP 368 PG 4 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BU66F UT WOS:000176639900069 ER PT J AU Case, JL Manobianco, J Oram, TD Garner, T Blottman, PF Spratt, SM AF Case, JL Manobianco, J Oram, TD Garner, T Blottman, PF Spratt, SM TI Local data integration over east-central Florida using the ARPS Data Analysis System SO WEATHER AND FORECASTING LA English DT Article ID NATIONAL-WEATHER-SERVICE; WIND ANALYSIS; INITIALIZATION; PREDICTION; LAPS; RAMS AB The Applied Meteorology Unit has configured the Advanced Regional Prediction System (ARPS) Data Analysis System (ADAS) to support operational short-range weather forecasting over east-central Florida, including the Kennedy Space Center and Cape Canaveral Air Force Station. The ADAS was modified to assimilate nationally and locally available in situ and remotely sensed observational data into a series of high-resolution gridded analyses every 15 min. The goal for running ADAS over east-central Florida is to generate real-time analysis products that may enhance weather nowcasts and short-range (,6 h) forecasts issued by the 45th Weather Squadron (45 WS), the Spaceflight Meteorology Group (SMG), and the National Weather Service (NWS) at Melbourne, Florida (MLB). The locally configured ADAS has the potential to provide added value because it ingests all operationally available data into a single grid analysis at high spatial and temporal resolutions. ADAS-generated grid analyses can provide forecasters with a tool to develop a more comprehensive understanding of evolving fine-scale weather features than could be obtained by individually examining the disparate data sources. The potential utility of this ADAS configuration to operational forecasters is demonstrated through a postanalysis case study of a thunderstorm outflow boundary that postponed an Atlas space launch mission, and a Florida cool-season squall line event. In the Atlas case study, a thunderstorm outflow boundary generated strong winds that exceeded the Atlas vehicle limits. A diagnosis of this event, using analysis products during the decaying phase of a Florida summer thunderstorm, illustrates the potential benefits that may be provided to forecasters supporting space launch and landing operations, and to NWS MLB meteorologists generating short-range forecast products. The evolution of analyzed cloud fields from the squall line event were used to track the areal coverage and tendencies of cloud ceiling and cloud-top heights that impact the evaluation of space operation weather constraints and NWS aviation products. These cases also illustrate how the analyses can provide guidance for nowcasts and short-range forecasts of Florida warm-season convection and fire-weather parameters. In addition, some of the sensitivities of the ADAS analyses to selected observational data sources are discussed. Recently, a real-time version of ADAS was implemented at both SMG and the NWS MLB forecast offices. Future plans of this ADAS configuration include incorporating additional observational datasets and designing visualization products for specific forecast tasks. Finally, the ultimate goal is to use these ADAS analyses to initialize a high-resolution numerical weather prediction model run locally at SMG and the NWS MLB, in order to develop a cycling scheme that preserves fine-scale features such as convective outflow boundaries in short-range numerical forecasts. C1 ENSCO Inc, Cocoa Beach, FL 32931 USA. NASA, Appl Meteorol Unit, Kennedy Space Ctr, FL USA. NASA, Spaceflight Meteorol Grp, Johnson Space Ctr, TX USA. NOAA, Natl Weather Serv, Melbourne, FL USA. RP Case, JL (reprint author), ENSCO Inc, 1980 N Atlantic Ave,Suite 230, Cocoa Beach, FL 32931 USA. NR 42 TC 11 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PY 2002 VL 17 IS 1 BP 3 EP 26 DI 10.1175/1520-0434(2002)017<0003:LDIOEC>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 514RG UT WOS:000173454400001 ER PT B AU Gilliam, D AF Gilliam, D GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Summary report on enterprise security workshop SO WET ICE 2002: ELEVENTH IEEE INTERNATIONAL WORKSHOPS ON ENABLING TECHNOLOGIES: INFRASTRUCTURE FOR COLLABORATIVE ENTERPRISES, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Workshop on Enabling Technologies - Infrastructure for Collaborative Enterprises (WET ICE 2002) CY JUN 10-12, 2002 CL CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST, PITTSBURGH, PA SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Data Engn, W Virginia Univ, Concurrent Engn Res Ctr, Linkoping Univ HO CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST AB This report summarizes the presentations of the 7(th) IEEE Workshops on enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE 2002), Enterprise Security (ES) Workshop. The ES Workshop had 13 papers, 2 poster papers and 1 specialty paper presented The topics covered the following: Anonymity and Cryptography, Authentication and Access Control, Communication Security, Intrusion Detection, and Software and Network Security. Professor Jeannette Wing of Carnegie Mellon University, gave the Plenary Address on the topic of "Vulnerability Analysis of Networked Systems." At the joint WETICE session, the ES Workshop Summary Report was presented describing the activities and discussions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Gilliam, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1748-X PY 2002 BP 43 EP 46 PG 4 WC Computer Science, Information Systems SC Computer Science GA BV34W UT WOS:000178627700007 ER PT B AU Sherif, JS Dearmond, TG AF Sherif, JS Dearmond, TG GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Intrusion detection: Systems and models SO WET ICE 2002: ELEVENTH IEEE INTERNATIONAL WORKSHOPS ON ENABLING TECHNOLOGIES: INFRASTRUCTURE FOR COLLABORATIVE ENTERPRISES, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Workshop on Enabling Technologies - Infrastructure for Collaborative Enterprises (WET ICE 2002) CY JUN 10-12, 2002 CL CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST, PITTSBURGH, PA SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Data Engn, W Virginia Univ, Concurrent Engn Res Ctr, Linkoping Univ HO CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST AB Organizations more often than not lack comprehensive security policies and are not adequately prepared to protect their systems against intrusions. This paper puts forward a review of state of the art and state of the applicability of intrusion detection systems, and models. The paper also presents a classification of literature pertaining to intrusion detection. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sherif, JS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Jsherif@fullerton.edu; Tommy.G.Dearmond-jr-104856@jpl.nasa.gov NR 205 TC 11 Z9 12 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 0-7695-1748-X PY 2002 BP 115 EP 133 DI 10.1109/ENABL.2002.1029998 PG 19 WC Computer Science, Information Systems SC Computer Science GA BV34W UT WOS:000178627700019 ER PT B AU Wolfe, TL Liu, YCJ Chang, HPP AF Wolfe, TL Liu, YCJ Chang, HPP GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Maintaining remote services and resources over the Internet and other networks SO WET ICE 2002: ELEVENTH IEEE INTERNATIONAL WORKSHOPS ON ENABLING TECHNOLOGIES: INFRASTRUCTURE FOR COLLABORATIVE ENTERPRISES, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Workshop on Enabling Technologies - Infrastructure for Collaborative Enterprises (WET ICE 2002) CY JUN 10-12, 2002 CL CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST, PITTSBURGH, PA SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Data Engn, W Virginia Univ, Concurrent Engn Res Ctr, Linkoping Univ HO CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST AB Many organizations are discovering the need to protect themselves with isolation routers, firewalls, and other technologies. Simultaneously they are collaborating more and more with external organizations. When local services and resources must be shared externally, problems arise. Servers at remote locations can provide copies of local services and resources. Offering services and resources via remote servers means that the home organization must also control access to these services and resources. This paper defines a Remote Node Architecture (RNA) that can house multiple services and resources. The RNA provides secure communications between the Remote Node and the home organization for all services and resources, and between the RNA services and resources and the users thereof. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Wolfe, TL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 5 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 0-7695-1748-X PY 2002 BP 137 EP 138 DI 10.1109/ENABL.2002.1029999 PG 2 WC Computer Science, Information Systems SC Computer Science GA BV34W UT WOS:000178627700020 ER PT B AU Gilliam, DP Powell, JD AF Gilliam, DP Powell, JD GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Integrating a Flexible Modeling Framework (IMF) with the network security assessment instrument to reduce software security risk SO WET ICE 2002: ELEVENTH IEEE INTERNATIONAL WORKSHOPS ON ENABLING TECHNOLOGIES: INFRASTRUCTURE FOR COLLABORATIVE ENTERPRISES, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Workshop on Enabling Technologies - Infrastructure for Collaborative Enterprises (WET ICE 2002) CY JUN 10-12, 2002 CL CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST, PITTSBURGH, PA SP IEEE Comp Soc, IEEE Comp Soc, Tech Comm Data Engn, W Virginia Univ, Concurrent Engn Res Ctr, Linkoping Univ HO CARNEGIE MELLON UNIV, INST COMPLEX ENGN SYST AB The network security assessment instrument is a comprehensive set of tools that can be used individually or collectively to ensure the security of network aware software applications and systems. Using the various tools collectively provide a distinct advantage for assuring the security of software and systems. Each tool's resulting output provides feedback into the other tools. Thus, more comprehensive assessment results are attained through the leverage each tool provides to the other when they are employed in concert. Previous portions of this work were presented at the IEEE Wet Ice 2000 and 2001 Workshops and are printed in those proceedings. This paper presents a portion of an overall research project on the generation of the network security assessment instrument to aid developers in assessing and assuring the security of software in the development and maintenance lifecycles. This portion, the Flexible Modeling Framework (FMF), focuses on modeling requirements and early lifecycle designs to discover vulnerabilities that result from interaction between system components that are either under development in a new system or proposed as additions to an existing system. There are early indications that this new approach, the Flexible Modeling Framework (FMF), has promise in the areas of network security as well as other critical areas such as system safety. Information about the overall research effort regarding network security is available at http://security.jpl.nasa.gov/rssr. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Gilliam, DP (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM David.Gilliam@jpl.nasa.gov; John.Powell@jpl.nasa.gov NR 9 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 0-7695-1748-X PY 2002 BP 153 EP 158 PG 6 WC Computer Science, Information Systems SC Computer Science GA BV34W UT WOS:000178627700023 ER PT S AU Palosz, W Grasza, K Boyd, PR Cui, Y Wright, G Roy, UN Burger, A AF Palosz, W Grasza, K Boyd, PR Cui, Y Wright, G Roy, UN Burger, A BE James, RB Franks, LA Burger, A Westbrook, EM Durst, RD TI Photoluminescence of CdTe crystals grown by 'contactless' PVT method SO X-RAY AND GAMMA-RAY DETECTORS AND APPLICATIONS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Hard X-Ray and Gamma-Ray Detector Physics IV/Conference on X-Ray Detectors CY JUL 07-09, 2002 CL SEATTLE, WA SP SPIE, Boeing Co, Pacific NW Natl Lab, Washington State Univ, Coll Sci, Washington State Univ, Coll Engn & Architecture, Washington Technol Ctr, Univ Washington, Coll Engn, Univ Washington, Ctr Nanotechnol DE PL spectra; CdTe : Al; CdTe : In; CdTe : Sc ID ACCEPTORS; DEFECTS; AG AB High quality CdTe crystals with resistivities higher than 10(8) Omega cm were grown by the 'contactless' PVT technique: Group III elements In and Al, and the transition metal Sc were introduced at the nominal level of about 6 ppm to the source material. Low-temperature photoluminescence (PL) has been employed to identify the origins of PL emissions of the crystals. It was found that the emission. peaks at 1.584 eV and 1.581 eV exist only in the In-doped crystal. The result suggests that the luminescence line at 1.584 eV is associated with Cd-vacancy/indium complex. The intensity of the broadband centered at 1.43 eV decreases dramatically with introduction of Sc. C1 NASA, George C Marshall Space Flight Ctr, USRA, Huntsville, AL 35812 USA. RP Palosz, W (reprint author), NASA, George C Marshall Space Flight Ctr, USRA, SD46, Huntsville, AL 35812 USA. NR 22 TC 0 Z9 0 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 0-8194-4551-7 J9 P SOC PHOTO-OPT INS PY 2002 VL 4784 BP 299 EP 304 DI 10.1117/12.455696 PG 6 WC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology; Spectroscopy SC Instruments & Instrumentation; Optics; Imaging Science & Photographic Technology; Spectroscopy GA BW25A UT WOS:000181335000030 ER PT S AU Weisskopf, MC AF Weisskopf, MC BE Gorenstein, P Hoover, RB TI Two years of observations with the Chandra X-Ray Observatory (CXO) SO X-RAY OPTICS FOR ASTRONOMY: TELESCOPES, MULTILAYERS, SPECTROMETERS, AND MISSIONS SE Proceedings of SPIE-The International Society for Optical Engineering LA English DT Proceedings Paper CT Conference on X-Ray Optics for Astronomy - Telescopes, Multilayers, Spectrometers, and Missions CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE Chandra; CXO; space missions; x rays; grazing-incidence optics; gratings; detectors; x-ray imaging; x-ray spectroscopy; x-ray astronomy ID FLIGHT CONTAMINATION MONITOR; CALIBRATION; RADIATION; LINES; LETGS; CCDS AB The first x-rays detected were detected on 1999, August 12. The instrumentation is operating as expected. Together with other space observatories we are entering a new era of discovery in high-energy astrophysics. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Weisskopf, MC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM martin@smoker.msfc.nasa.gov NR 23 TC 0 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 0-8194-4210-0 J9 P SOC PHOTO-OPT INS PY 2002 VL 4496 BP 1 EP 7 DI 10.1117/12.454360 PG 7 WC Astronomy & Astrophysics; Optics; Spectroscopy SC Astronomy & Astrophysics; Optics; Spectroscopy GA BU13M UT WOS:000175125900001 ER PT S AU Owens, SM Berendse, F Okajima, T Misaki, K Ogasaka, Y Tamura, K Tawara, Y Kunieda, H Chan, KW Soong, Y Baumgartner, WH Krimm, H Tueller, J Serlemitsos, PJ Yamashita, K Haga, K Ichimaru, S Takahashi, S Gotou, A Kitou, H Fukuda, S Kamata, Y Furuzawa, A Akimoto, F Yoshioka, T Kondou, K Haba, Y Tanaka, T AF Owens, SM Berendse, F Okajima, T Misaki, K Ogasaka, Y Tamura, K Tawara, Y Kunieda, H Chan, KW Soong, Y Baumgartner, WH Krimm, H Tueller, J Serlemitsos, PJ Yamashita, K Haga, K Ichimaru, S Takahashi, S Gotou, A Kitou, H Fukuda, S Kamata, Y Furuzawa, A Akimoto, F Yoshioka, T Kondou, K Haba, Y Tanaka, T BE Gorenstein, P Hoover, RB TI Characterization and performance of the InFOC mu S 20-40 keV x-ray focusing mirror SO X-RAY OPTICS FOR ASTRONOMY: TELESCOPES, MULTILAYERS, SPECTROMETERS, AND MISSIONS SE Proceedings of SPIE-The International Society for Optical Engineering LA English DT Proceedings Paper CT Conference on X-Ray Optics for Astronomy - Telescopes, Multilayers, Spectrometers, and Missions CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE multilayer; supermirror; x-ray focusing; x-ray telescope; Pt/C multilayer AB Mass production of replicated thin aluminum x-ray reflecting foils for the InFOCmuS (International Focusing Optics Collaboration for Micro-Crab Sensitivity) balloon payload is complete, and the full mirror has been assembled. InFOCmuS is an 8-meter focal length hard x-ray telescope scheduled for first launch in July 2001 and will be the first instrument to focus and image x-rays at high energies (20-40 keV) using multilayer-based reflectors. The individual reflecting elements are replicated thin aluminum foils, in a conical approximation Wolter-I system similar to those built for ASCA and ASTRO-E. These previous imaging systems achieved half-power-diameters of 3.5 and 1.7-2.1 arcminutes respectively. The InFOCmuS mirror is expected to have angular resolution similar to the ASTRO-E mirror. The reflecting foils for InFOCmuS, however, utilize a vertically graded Pt/C multilayer to provide broad-band high-energy focusing. We present the results of our pre-flight characterization of the full mirror, including imaging and sensitivity evaluations. If possible, we will include imaging results from the first flight of a multilayer-based high-energy focusing telescope. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Owens, SM (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Tueller, Jack/D-5334-2012 NR 5 TC 5 Z9 5 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 0-8194-4210-0 J9 P SOC PHOTO-OPT INS PY 2002 VL 4496 BP 115 EP 126 DI 10.1117/12.454364 PG 12 WC Astronomy & Astrophysics; Optics; Spectroscopy SC Astronomy & Astrophysics; Optics; Spectroscopy GA BU13M UT WOS:000175125900012 ER PT S AU Ramsey, BD Alexander, CD Apple, JA Benson, CM Dietz, KL Elsner, RF Engelhaupt, DE Ghosh, KK Kolodziejczak, JJ O'Dell, SL Speegle, CO Swartz, DA Weisskopf, MC AF Ramsey, BD Alexander, CD Apple, JA Benson, CM Dietz, KL Elsner, RF Engelhaupt, DE Ghosh, KK Kolodziejczak, JJ O'Dell, SL Speegle, CO Swartz, DA Weisskopf, MC BE Gorenstein, P Hoover, RB TI HERO: program status and first images from a balloon-borne focusing hard-x-ray telescope SO X-RAY OPTICS FOR ASTRONOMY: TELESCOPES, MULTILAYERS, SPECTROMETERS, AND MISSIONS SE Proceedings of SPIE-The International Society for Optical Engineering LA English DT Proceedings Paper CT Conference on X-Ray Optics for Astronomy - Telescopes, Multilayers, Spectrometers, and Missions CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE hard x ray; optics; electroformed nickel replication AB HERO is a balloon payload featuring shallow-graze angle replicated optics for hard-x-ray imaging. When completed, the instrument will offer unprecedented sensitivity in the hard-x-ray region, giving thousands of sources to choose from for detailed study on long flights. A recent proof-of-concept flight captured the first hard-x-ray focused images of the Crab Nebula, Cygnus X-1 and GRS 1915+105. Full details of the HERO program are presented, including the design and performance of the optics, the detectors and the gondola. Results from the recent proving flight are discussed together, with expected future performance when the full science payload is completed. C1 NASA, George C Marshall Space Flight Ctr, Sci Directorate, Huntsville, AL 35812 USA. RP Ramsey, BD (reprint author), NASA, George C Marshall Space Flight Ctr, Sci Directorate, Huntsville, AL 35812 USA. EM Brian.Ramsey@msfc.nasa.gov OI O'Dell, Stephen/0000-0002-1868-8056 NR 3 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 0-8194-4210-0 J9 P SOC PHOTO-OPT INS PY 2002 VL 4496 BP 140 EP 145 DI 10.1117/12.454369 PG 6 WC Astronomy & Astrophysics; Optics; Spectroscopy SC Astronomy & Astrophysics; Optics; Spectroscopy GA BU13M UT WOS:000175125900015 ER PT B AU Tucker, DS Williams, P Tobbe, P AF Tucker, DS Williams, P Tobbe, P BE Frumar, M Nemec, P Wagner, T Frumarova, B Cernoskova, E TI An automated fiber puller for use in low-earth orbit SO XIIITH INTERNATIONAL SYMPOSIUM ON NON-OXIDE GLASSES AND NEW OPTICAL GLASSES PTS 1 AND 2 LA English DT Proceedings Paper CT 13th International Symposium on Non-Oxide Glasses and New Optical Glasses CY SEP 09-13, 2002 CL PARDUBICE, CZECH REPUBLIC SP Univ Pardubice, Res Ctr & Dept Gen & Inorgan Chem, Acad Sci Czech Republ Lab Solid State Chem, Univ Pardubice Acad Sci Lab Solid State Chem, Czech Glass Soc C1 NASA, NSSTC, MSFC, AL 35812 USA. RP Tucker, DS (reprint author), NASA, NSSTC, SD71, MSFC, AL 35812 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU UNIV PARDUBICE PI PARDUBICE PA STUDENTSKA 95, PARDUBICE 532 10, CZECH REPUBLIC BN 80-7194-461-0 PY 2002 BP 708 EP 709 PG 2 WC Materials Science, Ceramics; Optics SC Materials Science; Optics GA BV77E UT WOS:000179983300171 ER PT B AU Stoltz, NG Snyder, GJ AF Stoltz, NG Snyder, GJ GP IEEE IEEE TI Effects of annealing electrodeposited bismuth telluride films SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB Thermoelectric thin films exhibit different qualities when compared with bulk materials. The goal however is to achieve thermoelectric properties of bulk materials from electrodeposited thin films. Thin films are produced by electrochemical deposition at room temperature. In order to optimize thermoelectric figure of merit proper carrier concentration must be obtained. The carrier concentration can be observed through resistivity measurements of thin film Bi2Te3 n-type depositions on thin Chromium-Gold substrates. Seebeck coefficient measurements are performed on Bi2Te3 n-type thin films deposited on Molybdenum foil. Annealing samples in the presence of Hydrogen Argon forming gas increases thermopower and resistivity consistent with a decrease in carrier concentration. Annealing between 200 and 500 Celsius for 1 to 20 hours was tested. This produces films with resistivity of 1 mOmega cm but a Seebeck coefficient of only -60 muV/K. Samples are suspected of remaining too heavily doped even after annealing. These results suggest there are defects in thin films that cannot be removed by annealing alone. C1 Jet Prop Lab, Pasadena, CA 91009 USA. RP Stoltz, NG (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91009 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 4 TC 11 Z9 11 U1 1 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 28 EP 30 DI 10.1109/ICT.2002.1190258 PG 3 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500008 ER PT B AU Gerovac, N Snyder, GJ Caillat, T AF Gerovac, N Snyder, GJ Caillat, T GP IEEE IEEE TI Thermoelectric properties of n-type polycrystalline BixSb2-xTe3 alloys SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB (BixSb1-x)(2)Te-3 (.5 less than or equal to 5 x less than or equal to .7) polycrystalline samples were synthesized using a combination of melting and powder metallurgy techniques. The samples were hot pressed in graphite dies and cut perpendicular and parallel to the pressing direction. Samples were examined by microprobe analysis to determine their atomic composition. The thermoelectric properties were measured at room temperature in both directions. These properties include Seebeck coefficient, thermal conductivity, electrical resistivity, and Hall effect. The thermoelectric figure-of-merit, ZT, was calculated from these properties. The best ZT was similar to.5, given by annealed (Bi.7Sb.3)(2)Te-3. Selected samples were also annealed at various temperatures in an attempt to optimize ZT. The annealing substantially impacted the thermoelectric properties due to a combination of improved crystallinity and changes in defect concentration. These materials could potentially be incorporated into advanced thermoelectric unicouples for a variety of power generation applications. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gerovac, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 4 TC 10 Z9 10 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 31 EP 34 DI 10.1109/ICT.2002.1190259 PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500009 ER PT B AU Shields, V Caillat, T Fleurial, JP Zoltan, A Zoltan, L Tuchscherer, M AF Shields, V Caillat, T Fleurial, JP Zoltan, A Zoltan, L Tuchscherer, M GP IEEE IEEE TI Synthesis and thermoelectric properties of Co1-xNixP3 and CoAs3-xPx SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB Two types of promising phosphide skutterudite materials, Co1-xNixP3 (x = 0.025 to 0.70) and CoAs3-xPx (x = 0.5 to 0.10), have been synthesized and their thermoelectric properties measured. These compounds were prepared using a direct synthesis technique. The samples were hot pressed and analyzed by electron microprobe microscopy. Hall Effect measurements were conducted to determine the electrical conductivity, mobility and carrier concentration. In addition, Seebeck coefficient and thermal conductivity measurements were performed. The thermoelectric properties are presented and discussed as a function of temperature up to 1273 K. The thermal stability of the primary CoP3 was examined in a static vacuum under isothermal and in-gradient conditions. The effect of the presence of 1 atm of a cover gas on the material loss rate was analyzed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 4 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 64 EP 67 DI 10.1109/ICT.2002.1190266 PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500016 ER PT B AU Wang, S Snyder, GJ Caillat, T AF Wang, S Snyder, GJ Caillat, T GP IEEE IEEE TI Thermoelectric properties of Nb3SbxTe7-x compounds SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB Niobium antimony telluride, Nb3SbxTe7-x, was synthesized and tested for thermoelectric properties in the Thermoelectrics group at the Jet Propulsion Laboratory. The forty atoms per unit cell of Nb3Sb2Te5 and its varied mixture of atoms yield a complicated structure, suggesting that Nb3Sb2Te5 and related compounds may exhibit low thermal conductivity and hence a higher ZT value. Nb3SbxTe7-x compounds were synthesized and subsequently analyzed for their Seebeck voltage, heat conduction, and electrical resistivity. Results indicate that Nb3Sb2Te5 is a heavily doped semiconductor whose thermoelectric properties are compromised by compensating n-type and p-type carriers. Attempts to dope in favor of either carrier by varying the Sb:Te ratio yielded samples containing secondary metallic phases that dominated the transport properties of the resulting compounds. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, S (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 2 TC 5 Z9 5 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 170 EP 172 DI 10.1109/ICT.2002.1190292 PG 3 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500042 ER PT B AU Stark, D Snyder, GJ AF Stark, D Snyder, GJ GP IEEE IEEE TI The synthesis of CaZn2Sb2 and its thermoelectric properties SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB CaZn2Sb2 was prepared and examined for use as a high temperature thermoelectric material. It has a high Seebeck coefficient and high electrical conductivity-comparable to beta-Zn4Sb3.[1] These two properties are vital in determining the ability of the compound to change heat into electricity isentropically. The dimensionless figure of merit, ZT, a measure of the thermoelectric material's efficiency is defined as ZT = S2sigmaT / lambda where S is the Seebeck coefficient, Z the figure of merit, T the temperature, sigma the electrical conductivity, and lambda the thermal conductivity. However, due to its simple structure, CaZn2Sb2 has high lambda. Doping CaZn2Sb2 with Ga3+ or modifying the (Ca, Zn) to Sb ratio was also investigated. Samples were prepared from Zn, Sb, and the binary compound CaSb2. They were tested for material composition, structure, and thermoelectric properties. Results of this experiment are presented and discussed as are the applicability of these materials to future thermoelectric use. Conservative estimates show a ZT of .5 at 500degreesC; CaZn2Sb2 could be a good thermoelectric to use at temperatures above 400degreesC. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stark, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 277-207, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 7 TC 4 Z9 4 U1 2 U2 12 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 181 EP 184 DI 10.1109/ICT.2002.1190295 PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500045 ER PT B AU Ursell, TS Snyder, GJ AF Ursell, TS Snyder, GJ GP IEEE IEEE TI Compatibility of segmented thermoelectric generators SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB It is well known that power generation efficiency improves when materials with appropriate properties are combined either in a cascaded or segmented fashion across a temperature gradient. Past methods for determining materials used in segmentation were mainly concerned with materials that have the highest figure of merit in the temperature range(1,2). However, the example of SiGe segmented with Bi2Te3 and/or various skutterudites shows a marked decline in device efficiency even though SiGe has the highest figure of merit in the temperature range. The origin of the incompatibility of SiGe with other thermoelectric materials leads to a general definition of compatibility and intrinsic efficiency. The compatibility factor derived as s = (root1+ZT - 1) / alphaT is a function of only intrinsic material properties and temperature, which is represented by a ratio of current to conduction heat. For maximum efficiency the compatibility factor should not change much with temperature both within a single material, and in the segmented leg as a whole. This leads to a measure of compatibility not only between segments, but also within a segment. General temperature trends show that materials are more self compatible at higher temperatures, and segmentation is more difficult across a larger DeltaT. The compatibility factor can be used as a quantitative guide for deciding whether a material is better suited for segmentation or cascading. Analysis of compatibility factors and intrinsic efficiency for optimal segmentation are discussed, with intent to predict optimal material properties, temperature interfaces, and/or current/heat ratios. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Ursell, TS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 5 TC 23 Z9 23 U1 1 U2 12 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 412 EP 417 DI 10.1109/ICT.2002.1190349 PG 6 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500099 ER PT B AU Snyder, GJ Borshchevsky, A Zoltan, A Caillat, T Fleurial, JP Nesmith, B Mondt, J McBirney, T Allen, D Bass, JC Ghamaty, S Elsner, N Anatychuk, L AF Snyder, GJ Borshchevsky, A Zoltan, A Caillat, T Fleurial, JP Nesmith, B Mondt, J McBirney, T Allen, D Bass, JC Ghamaty, S Elsner, N Anatychuk, L GP IEEE IEEE TI Testing of milliwatt power source components SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB A milliwatt power source (MPS) has been developed to satisfy the requirements of several potential solar system exploration missions. The MPS is a small power source consisting of three major components: a space qualified heat source (RHU), a thermopile (thermoelectric converter or TEC) and a container to direct the RHU heat to the TEC. Thermopiles from Hi-Z Technology, Inc. of San Diego and the Institute of Thermoelectricity of Chernivtsi Ukraine suitable for the MPS were tested and shown to perform as expected, producing 40 mW of power with a temperature difference of about 170degreesC. Such thermopiles were successfully life tested for up to a year. A MPS container designed and built by Swales Aerospace was tested with both a TEC simulator and actual TEC. The Swales unit, tested under dynamic vacuum, provided less temperature difference than anticipated, such that the TEC produced 20 mW of power with heat input equivalent to a RHU. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Snyder, GJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015; OI Snyder, G. Jeffrey/0000-0003-1414-8682; Anatychuk, Lukyan/0000-0001-6547-2912 NR 7 TC 4 Z9 7 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 463 EP 470 DI 10.1109/ICT.2002.1190361 PG 8 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500111 ER PT B AU Foote, MC Kenyon, M Krueger, T Schofield, JT McCleese, DJ McCann, TA Jones, EW Soll, SL Dickie, MR Gaalema, S Hu, W AF Foote, MC Kenyon, M Krueger, T Schofield, JT McCleese, DJ McCann, TA Jones, EW Soll, SL Dickie, MR Gaalema, S Hu, W GP IEEE IEEE TI Linear and 2-D thermopile detector arrays using high-z thermoelectric materials SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB The Jet Propulsion Laboratory has, for several years now, maintained a thermopile detector array program to address NASA application niches. An established process exists for producing thermopile single detectors and linear arrays using Bi-Te and Bi-Sb-Te thermoelectric materials and bulk silicon micromachining techniques. The detectors and arrays typically have D* values of 1-2x10(9) cmHz (1/2)/W in vacuum. Arrays are being fabricated for the Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter spacecraft, to launch in 2005. A second effort is seeking to develop high performance two-dimensional arrays of thermopile detectors using surface micromachining to fabricate pixels on a substrate containing readout electronics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Foote, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 1 Z9 1 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 519 EP 522 DI 10.1109/ICT.2002.1190369 PG 4 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500119 ER PT B AU Lim, JR Snyder, GJ Huang, CK Hennan, JA Ryan, MA Fleurial, JP AF Lim, JR Snyder, GJ Huang, CK Hennan, JA Ryan, MA Fleurial, JP GP IEEE IEEE TI Thermoelectric microdevice fabrication process and evaluation at the jet propulsion laboratory (JPL) SO XXI INTERNATIONAL CONFERENCE ON THERMOELECTRICS, PROCEEDINGS ICT '02 LA English DT Proceedings Paper CT 21st International Conference on Thermoelectrics (ICT 02) CY AUG 25-29, 2002 CL LONG BEACH, CA SP Jet Propuls Lab, Calif Inst Technol, MIT AB Advances in the microelectronics industry have made it possible to fabricate a multitude of microdevices, such as microprocessors, microsensors, microcontrollers, and micro instruments. These electronic microdevices have significantly reduced power requirements but at the same time require more attention in terms of integrated thermal management and power management and distribution. Micro thermoelectric converters are considered a promising technology approach for meeting some of these new requirements. Thermoelectric microdevices can convert rejected or waste heat into usable electric power, at moderate (200-500K) temperatures and often with small temperature differentials. They can also be easily integrated and provide effective cooling for devices specific in optoelectronics, such as mid-IR lasers, dense-wavelength-division-multiplexing (DWDM) components and charge-coupled-device (CCD) detectors. In the Materials and Device Technology Group at JPL, we have developed a unique fabrication method for a thermoelectric microdevice that utilizes standard integrated circuit techniques in combination with electrochemical deposition of compound semiconductors (Bi2Te3/Bi2-xSbxTe3). Our fabrication process is innovative in the sense that we are able to electrochemically micro mold different thermoelectric elements, with the flexibility of adjusting geometry, materials composition or batch scalability. Successive layers of photoresist were patterned and electrochemically filled with compound semiconductor materials or metal interconnects (Au or Ni). A thermoelectric microdevice was built on either glass or an oxidized silicon substrate containing 63 couples (63 n-legs/63 p-legs) at approximately 20 microns in structure height and with a device area close to 1700 mum x 1700 mum. In cooling mode, we evaluated device performance using an IR camera and differential thermal imaging software. We were able to detect a maximum cooling effect of about 2K. in power generation mode, a 75 watt light source was illuminated directly above the device while the current generated was measured. A detailed step-by-step overview of the fabrication process will be given, as well as specifics in testing setups, results and future directions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lim, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 10 TC 11 Z9 11 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7683-8 PY 2002 BP 535 EP 539 PG 5 WC Thermodynamics; Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Thermodynamics; Engineering; Instruments & Instrumentation; Physics GA BW38B UT WOS:000181801500123 ER PT J AU Freed, AD Leonov, AI AF Freed, AD Leonov, AI TI The Bailey criterion: Statistical derivation and applications to interpretations of durability tests and chemical kinetics SO ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK LA English DT Article DE durability; Markovian stochastic process; damage; cure; cross-linking AB The Bailey durability criterion, well known in mechanics of materials, has also been used in other fields of study such as the kinetics of chemical reactions. This paper rationalizes the wide applicability of this criterion in terms of Markovian statistical properties of systems, Two particular cases are discussed as examples of the general approach: durability of a wide class of solid materials and cure (cross-linking) reactions employed for fabrications of thermosets and rubbers. C1 Univ Akron, Dept Polymer Engn, Akron, OH 44325 USA. NASA, Glenn Res Ctr, Polymers Branch, Cleveland, OH 44135 USA. RP Leonov, AI (reprint author), Univ Akron, Dept Polymer Engn, Akron, OH 44325 USA. NR 6 TC 4 Z9 4 U1 0 U2 2 PU BIRKHAUSER VERLAG AG PI BASEL PA VIADUKSTRASSE 40-44, PO BOX 133, CH-4010 BASEL, SWITZERLAND SN 0044-2275 J9 Z ANGEW MATH PHYS JI Z. Angew. Math. Phys. PD JAN PY 2002 VL 53 IS 1 BP 160 EP 166 DI 10.1007/s00033-002-8148-5 PG 7 WC Mathematics, Applied SC Mathematics GA 523WN UT WOS:000173980700012 ER PT J AU Palosz, B Grzanka, E Gierlotka, S Stel'makh, S Pielaszek, R Bismayer, U Neuefeind, J Weber, HP Proffen, T Von Dreele, R Palosz, W AF Palosz, B Grzanka, E Gierlotka, S Stel'makh, S Pielaszek, R Bismayer, U Neuefeind, J Weber, HP Proffen, T Von Dreele, R Palosz, W TI Analysis of short and long range atomic order in nanocrystalline diamonds with application of powder diffractometry SO ZEITSCHRIFT FUR KRISTALLOGRAPHIE LA English DT Article ID X-RAY-DIFFRACTION; SMALL PARTICLES; CDSE NANOCRYSTALS; SIZE DEPENDENCE; SURFACE STRESS; GOLD PARTICLES; HIGH-PRESSURE; NANOPARTICLES; PALLADIUM; COPPER AB Fundamental limitations, with respect to nanocrystalline materials, of the traditional elaboration of powder diffraction data like the Rietveld method are discussed. A tentative method of the analysis of powder diffraction patterns of nanocrystals based on the examination of the variation of lattice parameters calculated from individual Bragg lines (named the "apparent lattice parameter", alp) is introduced. We examine the application of our methodology using theoretical diffraction patterns computed for models of nanocrystals with a perfect crystal lattice and for grains with a two-phase, core-shell structure. We use the method for the analysis of X-ray and neutron experimental diffraction data of nanocrystalline diamond powders of 4, 6 and 12 nm in diameter. The effects of an internal pressure and strain at the grain surface are discussed. The results are based on the dependence of the alp values on the diffraction vector Q and on the PDF analysis. It is shown, that the experimental results lend a strong support to the concept of a two-phase structure of nanocrystalline diamond. C1 Polish Acad Sci, UNIPRESS, High Pressure Res Ctr, PL-01142 Warsaw, Poland. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. European Synchrotron Radiat Facil, SNBL, F-38043 Grenoble, France. DESY, HASYLAB, D-22603 Hamburg, Germany. Univ Hamburg, Mineral Petrog Inst, D-20146 Hamburg, Germany. RP Polish Acad Sci, UNIPRESS, High Pressure Res Ctr, Ul Sokolowska 29-37, PL-01142 Warsaw, Poland. EM PALOSZ@unipress.waw.pl RI Lujan Center, LANL/G-4896-2012; Neuefeind, Joerg/D-9990-2015; Proffen, Thomas/B-3585-2009 OI Neuefeind, Joerg/0000-0002-0563-1544; Proffen, Thomas/0000-0002-1408-6031 NR 52 TC 60 Z9 60 U1 1 U2 4 PU WALTER DE GRUYTER GMBH PI BERLIN PA GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY SN 0044-2968 J9 Z KRISTALLOGR JI Z. Kristall. PY 2002 VL 217 IS 10 BP 497 EP 509 DI 10.1524/zkri.217.10.497.20795 PG 13 WC Crystallography SC Crystallography GA 623XL UT WOS:000179728100001 ER PT J AU Whitacre, JF West, WC Ratnakumar, BV AF Whitacre, JF West, WC Ratnakumar, BV TI The influence of target history and deposition geometry on RF magnetron sputtered LiCoO2 thin films SO JOURNAL OF POWER SOURCES LA English DT Article DE thin LiCoO2 films; Rutherfords backscattering spectrometry; RF magnetron sputtering ID LITHIUM COBALT OXIDE; BATTERIES AB Thin LiCoO2 films, typically used as cathode layers in thin-film solid-state batteries were RF magnetron sputter-deposited using targets that were either freshly produced, or had seen over 100 h of sputter erosion. The substrates, as received (100) silicon wafers, were either held stationary or were rocked back and forth under the target. Film texturing, grain size, composition, and thickness were examined using X-ray diffraction (synchrotron light source), inductively coupled plasma-mass spectroscopy (ICP-MS), Rutherfords backscattering spectrometry (RBS) and stylus profilometry. Films that were sputtered from the heavily used target were, on average, lithium-deficient, while films deposited using the fresh target were slightly lithium-rich. Film thickness, composition, and type of crystallographic texture varied radially, in the plane of the film in the stationary substrate case, in a pattern that reflected the sputter target erosion ring. For films deposited with substrate motion, an ovular area was defined on the film in which composition, and texturing were essentially uniform. The Li/Co ratio in the target and subsequent films was found to decrease over many hours of sputtering. Possible causes for the compositional and orientational variations observed are discussed. (C) 2001 Elsevier Science B.V All rights reserved. C1 CALTECH, Jet Prop Lab, Electrochem Technol Grp, Ctr Integrated Space Micrsyst, Pasadena, CA 91109 USA. RP Whitacre, JF (reprint author), CALTECH, Jet Prop Lab, Electrochem Technol Grp, Ctr Integrated Space Micrsyst, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 20 Z9 23 U1 6 U2 25 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD DEC 30 PY 2001 VL 103 IS 1 BP 134 EP 139 DI 10.1016/S0378-7753(01)00849-7 PG 6 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 499XZ UT WOS:000172597200018 ER PT J AU Houser, PR Gupta, HV Shuttleworth, WJ Famiglietti, JS AF Houser, PR Gupta, HV Shuttleworth, WJ Famiglietti, JS TI Multiobjective calibration and sensitivity of a distributed land surface water and energy balance model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOIL-MOISTURE; SEMIARID RANGELAND; MONSOON 90; MULTICRITERIA METHODS; PREDICTIONS; PARAMETERS; VEGETATION; LASER; FLOW AB The feasibility of using spatially distributed information to improve the predictive ability of a spatially distributed land surface water and energy balance model (LSM) was explored at the U. S. Department of Agriculture Agricultural Research Service (USDA-ARS) Walnut Gulch Experimental Watershed in southeastern Arizona. The inclusion of spatially variable soil and vegetation information produced unrealistic simulations that were inconsistent with observations, which was likely an artifact of both discretely assigning a single set of parameters to a given area and inadequate knowledge of spatially varying parameter values. Because some of the model parameters were not measured or are abstract quantities a multiobjective least squares strategy was used to find catchment averaged parameter values that minimize the prediction error of latent heat flux, soil heat flux, and surface soil moisture. This resulted in a substantial improvement in the model's spatially distributed performance and yielded valuable insights into the interaction and optimal selection of model parameters. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. RP NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974,Bldg 33,Rm A322, Greenbelt, MD 20771 USA. EM Paul.Houser@gsfc.nasa.gov RI Gupta, Hoshin/D-1642-2010; Houser, Paul/J-9515-2013 OI Gupta, Hoshin/0000-0001-9855-2839; Houser, Paul/0000-0002-2991-0441 NR 48 TC 19 Z9 19 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33421 EP 33433 DI 10.1029/2000JD900803 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800003 ER PT J AU Grenfell, JL Shindell, DT Koch, D Rind, D AF Grenfell, JL Shindell, DT Koch, D Rind, D TI Chemistry-climate interactions in the Goddard Institute for Space Studies general circulation model 2. New insights into modeling the preindustrial atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC OZONE; FUTURE CHANGES; IMPACT; SIMULATION; NOX; EMISSIONS; AEROSOLS; OH AB We investigate the chemical (hydroxyl and ozone) and dynamical response to changing from present-day to preindustrial conditions in the Goddard Institute for Space Studies general circulation model. We identify three main improvements not included by many other works. First, our model includes interactive cloud calculations. Second, we reduce sulfate aerosol which impacts NO, partitioning hence Q, distributions. Third, we reduce sea surface temperatures and increase ocean ice coverage which impact water vapor and ground albedo, respectively. Changing the ocean data (hence water vapor and ozone) produces a potentially important feedback between the Hadley circulation and convective cloud cover. Our present-day run (run 1, control run) global mean OH value was 9.8 X 10(5) Molecules cm(-3). For our best estimate of preindustrial conditions run (run 2) which featured modified chemical emissions, sulfate aerosol, and sea surface temperatures/ocean ice, this value changed to 10.2 X 10(5) molecules cm(-3). Reducing only the chemical emissions to preindustrial levels in run 1 (run 3) resulted in this value increasing to 10.6 X 10(5) molecules cm(-3). Reducing the sulfate in run 3 to preindustrial levels (run 4) resulted in a small increase in global mean OH (10.7 X 10(5) molecules cm(-3)). Changing the ocean data in run 4 to preindustrial levels (run 5) led to a reduction in this value to 10.3 X 10(5) Molecules cm(-3). Mean tropospheric ozone burdens were 423, 306, 305, 305, and 310 Tg for runs 1-5, respectively. C1 Free Univ Berlin, Inst Meteorol, Stratospharengrp, D-12165 Berlin, Germany. Columbia Univ, Clin Res Ctr, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Free Univ Berlin, Inst Meteorol, Stratospharengrp, Carl Heinrich Becker Weg 16, D-12165 Berlin, Germany. EM grenfell@strat01.met.fu-berlin.de RI Shindell, Drew/D-4636-2012 NR 38 TC 23 Z9 23 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33435 EP 33451 DI 10.1029/2000JD000090 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800004 ER PT J AU Rosenfield, JE Schoeberl, MR AF Rosenfield, JE Schoeberl, MR TI On the origin of polar vortex air SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC ARCTIC VORTEX; POTENTIAL VORTICITY; 2-DIMENSIONAL MODEL; TRANSPORT; DESCENT; SIMULATION AB Forward and backward three-dimensional stratospheric polar vortex trajectory computations between fall and spring for each of the years 1992-1993 through 1999-2000 in the Northern Hemisphere and the years 1992-1999 in the Southern Hemisphere have been carried out. We find that the forward and backward trajectories give very different pictures of polar vortex descent. The backward trajectories show a complex distribution of parcels in which one population originates in the upper stratosphere and mesosphere and experiences considerable descent in the polar regions, while the remaining parcels originate at lower altitudes of the middle and lower stratosphere and are mixed into the polar regions during vortex formation. The forward trajectory calculations do not show this second population since the parcels in the forward calculation originate within the protovortex. The amount of descent experienced by the first population shows little variability from year to year, while the computed descent and mixing of the remaining parcels show considerable interannual variability due to the varying polar meteorology. Spring methane values reconstructed from Halogen Occultation Experiment (HALOE) fall data and the back trajectories compare fairly well with typical HALOE spring values. These results imply that using a comparison between prewinter and postwinter tracer profiles to estimate the amount of descent over the fall-to-spring time period might result in unrealistically large values of descent, since the fall profiles are not representative of the same air as the spring profiles. Additional back trajectory calculations of descent in the lower stratosphere over 3-month time periods from spring to midwinter show that very little mixing occurs at these times and altitudes in the Northern Hemisphere during winters when the vortex is undisturbed, and in the Southern Hemisphere for all years studied. Thus, for this shorter time period, tracking constant mixing ratios of tracers within the vortex should give reasonable estimates of descent amounts, except for years when there are meteorological disturbances in the Northern Hemisphere. C1 Gen Sci Corp, Beltsville, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. EM rose@euterpe.gsfc.nasa.gov NR 22 TC 22 Z9 22 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33485 EP 33497 DI 10.1029/2001JD000365 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800008 ER PT J AU Hall, FG AF Hall, FG TI Introduction to special section: BOREAS III SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LAND-SURFACE; FIFE; DIRECTIONS; ATMOSPHERE AB The goal of the Boreal Ecosystem-Atmosphere Study (BOREAS) was to improve our understanding of the interactions between the boreal forest biome and the atmosphere in order to clarify their roles in global change. This introduction briefly describes the papers within this BOREAS special section, the third in a series in the Journal of Geophysical Research Atmospheres, and how they relate to the overall BOREAS Guest Investigator program, the final phase of the BOREAS experiment. The major contributions of BOREAS are also summarized, and future directions are identified. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM fghall@ltpsun.gsfc.nasa.gov NR 13 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33511 EP 33516 DI 10.1029/2001JD001526 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800010 ER PT J AU Newcomer, JA Huemmrich, KF Landis, D Nickeson, J Conrad, S Knapp, D Curd, S Morrell, A Hodkinson, D Nelson, E Cihlar, J Margolis, H Goodison, B Hall, F Sellers, PJ AF Newcomer, JA Huemmrich, KF Landis, D Nickeson, J Conrad, S Knapp, D Curd, S Morrell, A Hodkinson, D Nelson, E Cihlar, J Margolis, H Goodison, B Hall, F Sellers, PJ TI Managing and supporting large integrated and interdisciplinary field studies: The BOREAS example SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EXPERIMENT FIFE; HAPEX-SAHEL; VALIDATION; SCALE AB Large integrated and interdisciplinary field studies, such as the Boreal Ecosystem-Atmosphere Study (BOREAS), are conducted to refine our understanding of the interactions between the land surface and the atmosphere. Viewed as a case study, the BOREAS research objectives and final data set exemplify the complex nature and requirements of earth systems science research. The management and data system activities required to execute the study also echo this complexity. Rather than several research teams providing the needed management and data support, BOREAS management used a dedicated project staff to handle these functions. As the study progressed, the project staff transitioned from support of logistics and study management to information system operation and data publication, drawing upon the background knowledge gained from the earlier stages of the project. Data publication involves the creation and distribution of quality-checked and documented data with all ancillary information required to make it useful to someone unfamiliar with the study. We assert that the success of large integrated and interdisciplinary field studies depends upon having a dedicated staff. This staff focuses on the overall goals of the study throughout all phases of the effort: contributing to project planning, logistics, management, and data collection efforts; distributing, quality checking, and integrating the diverse data sets; working with the science teams to develop standardized data set documentation; integrating the diverse data and documentation for archiving; and publishing the data for long-term use by the larger scientific community. In this paper, the different phases of BOREAS are discussed, and the contributions that the dedicated staff made are examined. The value of spending resources on a centralized staff for project support and data publication activities is also examined. C1 Raytheon ITSS, Lanham, MD 20706 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Acad 4, Baltimore, MD 21250 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Canada Ctr Remote Sensing, Applicat Div, Ottawa, ON K1A OY7, Canada. Univ Laval, Fac Foresterie & Geomat, Ste Foy, PQ G1K 7P4, Canada. Meteorol Serv Canada, Climate Res Branch, Downsview, ON M3H 5T4, Canada. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Raytheon ITSS, 4500 Forbes Blvd, Lanham, MD 20706 USA. EM Jeffrey_Newcomer@Raytheon.com NR 23 TC 3 Z9 3 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33517 EP 33528 DI 10.1029/2001JD900124 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800011 ER PT J AU Rapalee, G Steyaert, LT Hall, FG AF Rapalee, G Steyaert, LT Hall, FG TI Moss and lichen cover mapping at local and regional scales in the boreal forest ecosystem of central Canada - art. no. 2001JD000509 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERE TRANSFER SCHEME; ENERGY-BALANCE PROCESSES; PEATLAND COMPLEX; WESTERN CANADA; CARBON BALANCE; SPRUCE FOREST; CO2 EXCHANGE; NORTHERN; WATER; SENSITIVITY AB Mosses and lichens are important components of boreal landscapes [Vitt et al., 1994; Bubier et al., 1997]. They affect plant productivity and belowground carbon sequestration and alter the surface runoff and energy balance. We report the use of multiresolution satellite data to map moss and lichens over the BOREAS region at a 10 in, 30 in, and I km scales. Our moss and lichen classification at the 10 in scale is based on ground observations of associations among soil drainage classes, overstory composition, and cover type among four broad classes of ground cover (feather, sphagnum, and brown mosses and lichens). For our 30 in map, we used field observations of ground cover-overstory associations to map mosses and lichens in the BOREAS southern study area (SSA). To scale up to a I km (AVHRR) moss map of the BOREAS region, we used the TM SSA mosaics plus regional field data to identify AVHRR overstory-ground cover associations. We found that: 1) ground cover, overstory composition and density are highly correlated, permitting inference of moss and lichen cover from satellite-based land cover classifications; 2) our I m moss map reveals that mosses dominate the boreal landscape of central Canada, thereby a significant factor for water, energy, and carbon modeling; 3) TM and AVHRR moss cover maps are comparable; 4) satellite data resolution is important, particularly in detecting the smaller wetland features, lakes, and upland jack pine sites; and 5) distinct regional patterns of moss and lichen cover correspond to latitudinal and elevational gradients. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. US Geol Survey, EROS Data Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Greenbelt, MD 20771 USA. RP 3056 Camels Hump Rd, N Duxbury, VT USA. EM steyaert@ltpmail.gsfc.nasa.gov; fghall@ltpmail.gsfc.nasa.gov NR 36 TC 15 Z9 16 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33551 EP 33563 DI 10.1029/2001JD000509 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800014 ER PT J AU Amthor, JS Chen, JM Clein, JS Frolking, SE Goulden, ML Grant, RF Kimball, JS King, AW McGuire, AD Nikolov, NT Potter, CS Wang, S Wofsy, SC AF Amthor, JS Chen, JM Clein, JS Frolking, SE Goulden, ML Grant, RF Kimball, JS King, AW McGuire, AD Nikolov, NT Potter, CS Wang, S Wofsy, SC TI Boreal forest CO2 exchange and evapotranspiration predicted by nine ecosystem process models: Intermodel comparisons and relationships to field measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NET PRIMARY PRODUCTION; ATMOSPHERIC CARBON-DIOXIDE; BLACK SPRUCE FOREST; LAND-SURFACE SCHEME; JACK PINE FOREST; GENERAL-MODEL; REGIONAL APPLICATIONS; PHOTOSYNTHESIS MODEL; CLIMATE VARIABILITY; SOIL AB Nine ecosystem process models were used to predict CO2 and water vapor exchanges by a 150-year-old black spruce forest in central Canada during 1994-1996 to evaluate and improve the models. Three models had hourly time steps, five had daily time steps, and one had monthly time steps. Model input included site ecosystem characteristics and meteorology. Model predictions were compared to eddy covariance (EC) measurements of whole-ecosystem CO2 exchange and evapotranspiration, to chamber measurements of nighttime moss-surface CO2 release, and to ground-based estimates of annual gross primary production, net primary production, net ecosystem production (NEP), plant respiration, and decomposition. Model-model differences were apparent for all variables. Model-measurement agreement was good in some cases but poor in others. Modeled annual NEP ranged from -11 g C m(-2) (weak CO2 source) to 85 g C m(-2) (moderate CO2 sink). The models generally predicted greater annual CO2 sink activity than measured by EC, a discrepancy consistent with the fact that model parameterizations represented the more productive fraction of the EC tower "footprint." At hourly to monthly timescales, predictions bracketed EC measurements so median predictions were similar to measurements, but there were quantitatively important model-measurement discrepancies found for all models at subannual timescales. For these models and input data, hourly time steps (and greater complexity) compared to daily time steps tended to improve model-measurement agreement for daily scale CO2 exchange and evapotranspiration (as judged by root-mean-squared error). Model time step and complexity played only small roles in monthly to annual predictions. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2E3, Canada. Univ Montana, Missoula, MT 59801 USA. Univ Alaska, US Geol Survey, Alaska Cooperat Fish & Wildlife Res Unit, Fairbanks, AK 99775 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. Harvard Univ, Div Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. RP Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. EM amthor@aya.yale.edu RI Goulden, Michael/B-9934-2008; Amthor, Jeffrey/F-2696-2016; OI Amthor, Jeffrey/0000-0002-1410-6100; Wang, Shusen/0000-0003-1860-899X NR 74 TC 98 Z9 104 U1 0 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33623 EP 33648 DI 10.1029/2000JD900850 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800019 ER PT J AU Potter, CS Wang, SS Nikolov, NT McGuire, AD Liu, J King, AW Kimball, JS Grant, RF Frolking, SE Clein, JS Chen, JM Amthor, JS AF Potter, CS Wang, SS Nikolov, NT McGuire, AD Liu, J King, AW Kimball, JS Grant, RF Frolking, SE Clein, JS Chen, JM Amthor, JS TI Comparison of boreal ecosystem model sensitivity to variability in climate and forest site parameters SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NET PRIMARY PRODUCTION; LEAF-AREA INDEX; ATMOSPHERIC CARBON-DIOXIDE; BLACK SPRUCE FOREST; LAND-SURFACE SCHEME; CONIFER STANDS; ELEVATED CO2; JACK PINE; PRODUCTIVITY; EXCHANGE AB Ecosystem models are useful tools for evaluating environmental controls on carbon and water cycles under past or future conditions. In this paper we compare annual carbon and water fluxes from nine boreal spruce forest ecosystem models in a series of sensitivity simulations. For each comparison, a single climate driver or forest site parameter was altered in a separate sensitivity run. Driver and parameter changes were prescribed principally to be large enough to identify and isolate any major differences in model responses, while also remaining within the range of variability that the boreal forest biome may be exposed to over a time period of several decades. The models simulated plant production, autotrophic and heterotrophic respiration, and evapotranspiration (ET) for a black spruce site in the boreal forest of central Canada (56degreesN). Results revealed that there were common model responses in gross primary production, plant respiration, and ET fluxes to prescribed changes in air temperature or surface irradiance and to decreased precipitation amounts. The models were also similar in their responses to variations in canopy leaf area, leaf nitrogen content, and surface organic layer thickness. The models had different sensitivities to certain parameters, namely the net primary production response to increased CO2 levels, and the response of soil microbial respiration to precipitation inputs and soil wetness. These differences can be explained by the type (or absence) of photosynthesis-CO2 response curves in the models and by response algorithms of litter and humus decomposition to drying effects in organic soils of the boreal spruce ecosystem. Differences in the couplings of photosynthesis and soil respiration to nitrogen availability may also explain divergent model responses. Sensitivity comparisons imply that past conditions of the ecosystem represented in the models' initial standing wood and soil carbon pools, including historical climate patterns and the time since the last major disturbance, can be as important as potential climatic changes to prediction of the annual ecosystem carbon balance in this boreal spruce forest. C1 Univ Alberta, Edmonton, AB, Canada. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. US Geol Survey, Fairbanks, AK USA. Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. Univ Montana, Sch Forestry, Polson, MT 59860 USA. Univ New Hampshire, Dept Earth Sci, Durham, NH 03824 USA. Univ Alaska, Dept Biol & Wildlife, Fairbanks, AK 99775 USA. RP NASA, Ames Res Ctr, Mail Stop 242-2, Moffett Field, CA 94035 USA. EM cpotter@gaia.arc.nasa.gov RI Amthor, Jeffrey/F-2696-2016; OI Amthor, Jeffrey/0000-0002-1410-6100; Grant, Robert/0000-0002-8890-6231; Wang, Shusen/0000-0003-1860-899X NR 60 TC 32 Z9 35 U1 2 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33671 EP 33687 DI 10.1029/2000JD000224 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800021 ER PT J AU Abdalati, W AF Abdalati, W TI Special section: Mass balance of the Greenland ice sheet (PARCA) - Preface SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material C1 NASA Headquarters, Off Earth Sci, Washington, DC USA. RP NASA Headquarters, Off Earth Sci, Washington, DC USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33689 EP 33689 DI 10.1029/2001JD001430 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800022 ER PT J AU Thomas, R Csatho, B Davis, C Kim, C Krabill, W Manizade, S McConnell, J Sonntag, J AF Thomas, R Csatho, B Davis, C Kim, C Krabill, W Manizade, S McConnell, J Sonntag, J TI Mass balance of higher-elevation parts of the Greenland ice sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE RADAR ALTIMETRY; SNOW ACCUMULATION AB Satellite radar and aircraft laser altimeter data and a volume budget comparison of total snow accumulation with total ice discharge give three independent estimates of the recent mass balance of parts of the Greenland ice sheet above similar to2000 m elevation. Results show the entire region, on average, to be in balance to within 10 mm yr(-1), with very low rates of regional thickness change (dH/dt) in the northeast but high rates with large spatial variability in the south. Only the volume budget estimates show significant thinning in the northwest, but thinning in this area is also inferred from local measurements of ice vertical velocities down boreholes. South of latitude 68degreesN, there has been rapid thickening west of the ice divide, with equally rapid thinning in the southeast, but with large differences between the three estimates of dH/dt throughout this region. The radar data apply to the period 1978-1988, the laser data are for 1993/1994-1998/1999, and the volume budget calculations represent conditions over at least the last few decades. Consequently, many of the differences between results could be caused by temporal changes, particularly in snow accumulation rates, that occurred since the 1970s. However, taken with other information, our results suggest long-term thickening in the southwest and possibly quite recent onset of rapid thinning in the southeast. C1 EG&G Tech Serv, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Univ Missouri, Dept Elect Engn, Columbia, MO 65211 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Univ & Community Coll Syst Nevada, Desert Res Inst, Reno, NV 89512 USA. RP EG&G Tech Serv, Wallops Flight Facil, Bldg N-159, Wallops Isl, VA 23337 USA. EM thomas@osb.wff.nasa.gov; Csatho.1@osu.edu; davisch@missouri.edu; Kim.1@osu.edu; krabill@osbl.wff.nasa.gov; manizade@osb.wff.nasa.gov; jmcconn@dri.edu; sonntag@osb.wff.nasa.gov RI Kim, Changjoo/B-9362-2008 NR 27 TC 32 Z9 35 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33707 EP 33716 DI 10.1029/2001JD900033 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800024 ER PT J AU Zwally, HJ Giovinetto, MB AF Zwally, HJ Giovinetto, MB TI Balance mass flux and ice velocity across the equilibrium line in drainage systems of Greenland SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SHEET; ACCUMULATION; PRECIPITATION; INTERFEROMETRY; VARIABILITY; SEA AB Estimates of balance mass flux and depth-averaged ice velocity through the cross section aligned with the equilibrium line are produced for each of six drainage systems in Greenland. The estimates are based on a model equilibrium line fitted to field data and on a revised distribution of surface mass balance for the conterminous ice sheet. Ice drainage divides and six major drainage systems are delineated using surface topography from ERS radar altimeter data. Ice thicknesses at the equilibrium line and throughout each drainage system are based on the latest compilation of airborne radar sounding data described elsewhere. The net accumulation rate in the area bounded by the equilibrium line is 399 Gt a(-1), and net ablation rate in the remaining area is 231 Gt a(-1). Excluding an east central coastal ridge reduces the net accumulation rate to 397 Gt a(-1), with a range from 42 to 121 Gt a(-1) for the individual drainage systems. The mean balance mass flux and depth-averaged ice velocity at the cross-section aligned with the modeled equilibrium line are 0.1011 Gt km(2) a(-1) and 0.111 km a(-1), respectively, with little variation in these values from system to system. In contrast, the mean mass discharge per unit length along the equilibrium line ranges from one half to double the overall mean rate of 0.0468 Gt km(-1) a(-1). The ratio of the ice mass in the area bounded by the equilibrium line to the rate of mass output implies an effective exchange time of approximately 6 ka for total mass exchange. The range of exchange times, from a low of 3 ka in the SE drainage system to 14 ka in the NE, suggests a rank as to which regions of the ice sheet may respond more rapidly to climate fluctuations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon TSC ITSS, Greenbelt, MD USA. RP NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. EM jay.zwally@gsfc.nasa.gov; mario.giovinetto@gsfc.nasa.gov NR 40 TC 22 Z9 22 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33717 EP 33728 DI 10.1029/2001JD900120 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800025 ER PT J AU Abdalati, W Krabill, W Frederick, E Manizade, S Martin, C Sonntag, J Swift, R Thomas, R Wright, W Yungel, J AF Abdalati, W Krabill, W Frederick, E Manizade, S Martin, C Sonntag, J Swift, R Thomas, R Wright, W Yungel, J TI Outlet glacier and margin elevation changes: Near-coastal thinning of the Greenland ice sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADAR INTERFEROMETRY; SNOW ACCUMULATION; ENERGY-BALANCE; CLIMATE-CHANGE; ABLATION; SENSITIVITY AB Repeat surveys by aircraft laser altimeter in 1993/1994 and 1998/1999 have revealed significant thinning along many parts of the Greenland ice sheet at elevations below about 2000 m. In this paper we examine elevation changes from 29 repeat aircraft surveys over the lower portions of some of the larger outlet glaciers and parts of the ice sheet margin. Here thinning rates in excess of 1 m/yr are common in the lower sections of the flight lines, but in some cases, this rate is measured at elevations as high as 1500 m. Warmer summers along parts of the coast may have caused a few tens of cm/yr additional melting, but the magnitudes and character of the elevation changes suggest that in many cases they are more likely a result of glacier dynamics and creep thinning. The most extreme thinning was observed near the terminus of the Kangerdlugssuaq Glacier in southeastern Greenland where rates as high as 10 m/yr were measured. There are a few areas of significant thickening (over I m/yr), which is probably related to higher than normal accumulation rates during the observation period; but one location L, Bistrup Brae, had local regions of thickening of 8 to 9 m/yr. Three glaciers in the northeast show patterns of thickness change that may suggest surging behavior, and one has been independently documented as a surging glacier. Overall, the lowest reaches of the outlet glaciers and ice sheet edges appear to be changing significantly, with thinning observed more frequently than thickening. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, EG&G Serv, Wallops Isl, VA 23337 USA. RP NASA Headquarters, Code YS, Washington, DC 20546 USA. EM wabdalat@hq.nasa.gov NR 26 TC 61 Z9 62 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33729 EP 33741 DI 10.1029/2001JD900192 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800026 ER PT J AU Davis, CH McConnell, JR Bolzan, J Bamber, JL Thomas, RH Mosley-Thompson, E AF Davis, CH McConnell, JR Bolzan, J Bamber, JL Thomas, RH Mosley-Thompson, E TI Elevation change of the southern Greenland ice sheet from 1978 to 1988: Interpretation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE-RADAR ALTIMETRY; MASS-BALANCE; GROWTH; MODEL; SNOW AB The spatial pattern of elevation change estimates derived from satellite radar altimeter data for the period from 1978 to 1988 for the southern Greenland ice sheet is examined. As reported previously, the results from 12 ice cores widely distributed in the study area indicate that much of the spatial variability in the elevation change estimates can be explained by temporal variations in accumulation, Most notably, the areas of largest thickening and thinning, east and west of the ice divide around 66degreesN, recently experienced substantial decadal fluctuations in accumulation sufficient to explain the observed elevation change rates that span the range of +/-24 cm yr(-1). Elevation change estimates in the NW of the study area around the 2000-m elevation contour were found to be inconsistent with both short- and long-term changes in accumulation fluctuations. Examination of stratigraphy in several shallow ice cores in the NW indicates that significant melting took place in 1977 and 1978, and this was followed by many years of very little melt activity. This likely resulted in a significant downward bias in the 1978-1988 elevation change estimates in the NW. Comparison of measured surface velocities with those calculated assuming steady state balance show very good agreement overall, but there are many instances in the southeast where the steady state velocities are significantly smaller than measured surface velocities. We cannot rule out the possibility that increased ice flow in lower-elevation outlet glaciers has migrated farther upstream thereby causing negative long-term mass imbalance in southeast Greenland. C1 Univ Missouri, Dept Elect Engn, Columbia, MO 65211 USA. Univ & Community Coll Syst Nevada, Desert Res Inst, Reno, NV USA. Univ Bristol, Sch Geog Sci, Bristol Glaciol Ctr, Bristol BS8 1SS, Avon, England. NASA, Wallops Flight Facil, EG&G Serv, Wallops Isl, VA 23337 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Ohio State Univ, Dept Geog, Columbus, OH 43210 USA. RP Univ Missouri, Dept Elect Engn, 323 EBW, Columbia, MO 65211 USA. EM DavisCH@missouri.edu; jmcconn@dri.edu; j.bolzan@worldnet.att.net; j.l.bamber@bristol.ac.uk; robert_thomas@hotmail.com; thompson.4@osu.edu RI Bamber, Jonathan/C-7608-2011 OI Bamber, Jonathan/0000-0002-2280-2819 NR 32 TC 6 Z9 6 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33743 EP 33754 DI 10.1029/2001JD900167 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800027 ER PT J AU Gogineni, S Tammana, D Braaten, D Leuschen, C Akins, T Legarsky, J Kanagaratnam, P Stiles, J Allen, C Jezek, K AF Gogineni, S Tammana, D Braaten, D Leuschen, C Akins, T Legarsky, J Kanagaratnam, P Stiles, J Allen, C Jezek, K TI Coherent radar ice thickness measurements over the Greenland ice sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DEPTH SOUNDER; MIGRATION AB We developed two 150-MHz coherent radar depth sounders for ice thickness measurements over the Greenland ice sheet. We developed one of these using connectorized components and the other using radio frequency integrated circuits (RFICs). Both systems are designed to use pulse compression techniques and coherent integration to obtain the high sensitivity required to measure the thickness of more than 4 km of cold ice. We used these systems to collect radar data over the interior and margins of the ice sheet and several outlet glaciers. We operated both radar systems on the NASA P-3B aircraft equipped with GPS receivers. Radar data are tagged with GPS-derived location information and are collected in conjunction with laser altimeter measurements. We have reduced all data collected since 1993 and derived ice thickness along all flight lines flown in support of Program for Regional Climate Assessment (PARCA) investigations and the North Greenland Ice Core Project. Radar echograms and derived ice thickness data are placed on a server at the University of Kansas (http://tornado. rsl.ukans.edu/Greenlanddata.htm) for easy access by the scientific community. We obtained good ice thickness information with an accuracy of +/-10 m over 90% of the flight lines flown as a part of the PARCA initiative. In this paper we provide a brief description of the system along with samples of data over the interior, along the 2000-m contour line in the south and from a few selected outlet glaciers. C1 Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. Jet Prop Lab, Pasadena, CA USA. Univ Missouri, Dept Elect Engn, Columbia, MO USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. RP Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. EM gogineni@rsl.ukans.edu NR 19 TC 79 Z9 83 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33761 EP 33772 DI 10.1029/2001JD900183 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800029 ER PT J AU Fahnestock, M Abdalati, W Luo, S Gogineni, S AF Fahnestock, M Abdalati, W Luo, S Gogineni, S TI Internal layer tracing and age-depth-accumulation relationships for the northern Greenland ice sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CORE; RECORD AB Clues to previous ice sheet structure and long-term glaciological processes are preserved in the internal layering configuration of the Greenland ice sheet. Information about these internal layers has been retrieved over many parts of the ice sheet with the University of Kansas ice-penetrating radar. We report on the coherence of these layers over very large distances, describe a method of tracing these layers along thousands of kilometers of flight line, and do so for one flight during the 1999 Program for Arctic Regional Climate Assessment (PARCA) aircraft campaign. We determine the ages of these layers, based on information at the GRIP ice core site, and extend these ages along the flight line to Camp Century, where they are compared to modeled-derived age estimates. These ages agree with each other to between 2 and 15%, differences that can be substantially reduced with minor changes to the model parameters (accumulation rate and shear layer depth). Finally, we are able to derive estimates of accumulation rates along the flight line by fitting the age-depth data from layer tracing to a Dansgaard-Johnsen model with a minimization technique, providing estimates that match recent accumulation patterns within a few centimeters per year. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. RP Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. EM mark@essic.umd.edu; wabdalat@hq.nasa.gov; sluo@icesat2.gsfc.nasa.gov; gogineni@ittc.ukans.edu RI Fahnestock, Mark/N-2678-2013 NR 19 TC 34 Z9 34 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33789 EP 33797 DI 10.1029/2001JD900200 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800032 ER PT J AU Shuman, CA Bromwich, DH Kipfstuhl, J Schwager, M AF Shuman, CA Bromwich, DH Kipfstuhl, J Schwager, M TI Multiyear accumulation and temperature history near the North Greenland Ice Core Project site, north central Greenland SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SSM/I BRIGHTNESS TEMPERATURES; NITRATE FIRN CONCENTRATIONS; ISOTOPIC PALEOTHERMOMETER; BOREHOLE TEMPERATURES; DEPOSITION CHANGES; CLIMATE SIGNAL; SHEET; SNOW; PRECIPITATION; OXYGEN AB This paper presents a comparison of two independent methods of estimating subseasonal accumulation across the interior of Greenland. These methods, high-resolution snow pit studies and atmospheric modeling, have differing spatial and temporal resolution, but both can estimate net accumulation for subseasonal and shorter periods. The snow pit approach is based on a documented relationship between high-resolution snow pit profiles of oxygen stable isotope ratio (delta(18)O) and multiyear Special Sensor Microwave/Imager (SSM/I) 37-GHz brightness temperature records. Comparison of SSM/I data to profiles obtained during the 1995 Alfred Wegener Institut North Greenland Traverse field season shows that delta(18)O data from snow in north central Greenland are a reliable, high-resolution temperature proxy. This enables determination of accumulation amount, rate, and timing from approximately July 1991 through June 1995 across this 220-km-long transect of the ice sheet. Precipitation estimates derived from early modeling based on European Centre for Medium-Range Weather Forecasts data show a similar average seasonal pattern but a diminished magnitude of accumulation (similar to56%) for these sites. The slope of the multiyear T versus delta correlation was evaluated for each site on the basis of the observed and calculated temperature history from the nearby North Greenland Ice core Project (NGRIP) site automatic weather station. These data should assist interpretation of the paleoclimatic record in the NGRIP deep core. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. Ohio State Univ, Byrd Polar Res Ctr, Columbus, OH 43210 USA. Alfred Wegener Inst Polar & Marine Res, D-27568 Bremerhaven, Germany. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RP NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Bldg 33,Room A210,Code 971, Greenbelt, MD 20771 USA. EM christopher.shuman@gsfc.nasa.gov; bromwich@polarmet1.mps.ohio-state.edu; kipfstuhl@awi-bremerhaven.de RI Bromwich, David/C-9225-2016 NR 59 TC 12 Z9 12 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33853 EP 33866 DI 10.1029/2001JD900197 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800037 ER PT J AU Drinkwater, MR Long, DG Bingham, AW AF Drinkwater, MR Long, DG Bingham, AW TI Greenland snow accumulation estimates from satellite radar scatterometer data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NORTH-ATLANTIC OSCILLATION; PENCIL-BEAM SCATTEROMETER; SHEET SURFACE-PROPERTIES; ICE-SHEET; ENHANCED-RESOLUTION; ERS SCATTEROMETER; TEMPERATURE; ELEVATION; PRECIPITATION; BACKSCATTER AB Data collected by the C band ERS-2 wind scatterometer (EScat), the Ku band ADEOS-1 NASA scatterometer (NSCAT), and the Ku band SeaWinds on QuikScat (QSCAT) satellite instruments are used to illustrate spatiotemporal variability in snow accumulation on the Greenland ice sheet. Microwave radar backscatter images of Greenland are derived using the scatterometer image reconstruction (SIR) method at 3-day intervals over the periods 1991-1998 and 1996-1997 for EScat and NSCAT, respectively. The backscatter coefficient sigmadegrees normalized to 40degrees incidence, A, and gradient in backscatter, B, in the range 20degrees-60degrees are compared with historical snow accumulation data and recent measurements made in the Program for Arctic Regional Climate Assessment (PARCA) shallow snow pits. Empirical relationships derived from these comparisons reveal different exponential relationships between C and Ku band A values and dry snow zone mean annual accumulation, Q. Frequency difference images between overlapping scatterometer images suggest that C band data are more sensitive to snow layering and buried inhomogeneities, whereas Ku band data are more sensitive to volume scattering from recently accumulated snow. Direct comparisons between NSCAT B values and in situ Q measurements show a linear relationship between In (Q) and B, with a negative rank correlation of R = -0.8. The root-mean-square residual in fitting regression line equation In (Q) = 3.08 - 17.83B to the data is 0.05-m snow water equivalent. This simple Ku band empirical relationship is exploited to investigate decadal changes in dry snow zone accumulation between Seasat (1978) and NSCAT (1996). Additional comparisons between NSCAT and recent QSCAT (1999) data reveal significant upslope shifts in the dry snow line along the southwestern flank of the ice sheet. Recent acceleration in the increase in intensity of scattering is observed in the percolation zone, suggesting increased melting between 2000- and 3000-m elevation in the southern half of the ice sheet. C1 European Space Agcy, Div Earth Sci, NL-2200 AG Noordwijk, Netherlands. Brigham Young Univ, Microwave Remote Sensing Lab, Provo, UT 84602 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP European Space Agcy, Div Earth Sci, Keplerlaan 1,Postbus 299, NL-2200 AG Noordwijk, Netherlands. EM mark.drinkwater@esa.int; long@ee.byu.edu; andrew.bingham@jpl.nasa.gov RI Long, David/K-4908-2015; OI Long, David/0000-0002-1852-3972; Drinkwater, Mark/0000-0002-9250-3806 NR 56 TC 43 Z9 43 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33935 EP 33950 DI 10.1029/2001JD900107 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800042 ER PT J AU Abdalati, W Steffen, K AF Abdalati, W Steffen, K TI Greenland ice sheet melt extent: 1979-1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDTROPOSPHERIC CIRCULATION; MOUNT-PINATUBO; SURFACE MELT; F11 AB Analysis of melt extent on the Greenland ice sheet is updated to span the time period 1979-1999 and examined along with its spatial and temporal variability using passive microwave satellite data. To acquire the full record, the issue of continuity between the previous passive microwave sensors (SMMR, SSM/I F-8, and SSM/I F-11) and the most recent SSM/I F-13 sensor is addressed. The F-13 cross-polarized gradient ratio melt-classification threshold is determined to be -0.0154. Results show that for the 21-year record, a positive melt trend of nearly 1 %/yr is observed, but this trend falls just below the 90% significance level. The observed melt increase does appear to be driven by conditions in the western portion of the ice sheet, rather than the east where melt appears to have decreased slightly. Moreover, the eruption of Mount Pinatubo in 1991 is likely to have had some impact on the melt but not so much as previously suspected. The 1992 melt anomaly is 1.7 standard deviations from the mean. Finally, the relationship between coastal temperatures and melt extent suggests an increase in surface runoff contribution to sea level of 0.31 mm/yr for a 1degreesC temperature rise. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP NASA Headquarters, Code YS,300 E St SW, Washington, DC 20546 USA. EM wabdalat@hq.nasa.gov RI Steffen, Konrad/C-6027-2013 OI Steffen, Konrad/0000-0001-8658-1026 NR 25 TC 91 Z9 93 U1 4 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 33983 EP 33988 DI 10.1029/2001JD900181 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800045 ER PT J AU Rignot, E Gogineni, S Joughin, I Krabill, W AF Rignot, E Gogineni, S Joughin, I Krabill, W TI Contribution to the glaciology of northern Greenland from satellite radar interferometry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HINGE-LINE MIGRATION; ANTARCTIC ICE-SHEET; ENERGY-BALANCE; PETERMANN-GLETSCHER; HIGH-RESOLUTION; MASS-BALANCE; MODEL; FLOW; ABLATION; GLACIER AB Interferometric synthetic aperture radar (InSAR) data from the ERS-1 and ERS-2 satellites are used to measure the surface velocity, topography, and grounding line position of the major outlet glaciers in the northern sector of the Greenland ice sheet. The mass output of the glaciers at and above the grounding line is determined and compared with the mass input. We find that the grounding line output is approximately in balance I with the input, except for the three largest glaciers for which the mass loss is 4+/-3 km(3) ice year(-1) or 11+/-8% of the mass input. Along the coast we detect a systematic retreat of the grounding lines between 1992 and 1996 with InSAR, which implies that the outlet glaciers are thinning. The inferred coastal thinning is too large to be explained by a few warm summers. Glacier thinning must be of dynamic origin, that is, caused by spatial and temporal changes in ice velocity. Iceberg production from the glaciers is uncharacteristically low. It accounts for only 8% of the ice discharge to the ocean. About 55% of the ice is lost through basal melting (5-8 m ice year(-1) on average) from the underside of the floating glacier tongues that are in contact with warm ocean waters. Mass losses are highest in the first 10 km of floating ice, where ice reaches the greatest depths and basal melting is 3 times larger than on average. Only a small increase in basal melting would suffice to disintegrate the floating glacier tongues. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. NASA, Goddard Space Flight Ctr, Wallops Facil, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM eric@adelie.ipl.nasa.gov RI Joughin, Ian/A-2998-2008; Rignot, Eric/A-4560-2014 OI Joughin, Ian/0000-0001-6229-679X; Rignot, Eric/0000-0002-3366-0481 NR 49 TC 36 Z9 36 U1 0 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 34007 EP 34019 DI 10.1029/2001JD900071 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800047 ER PT J AU Joughin, I Fahnestock, M MacAyeal, D Bamber, JL Gogineni, P AF Joughin, I Fahnestock, M MacAyeal, D Bamber, JL Gogineni, P TI Observation and analysis of ice flow in the largest Greenland ice stream SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE RADAR INTERFEROMETRY; WEST ANTARCTICA; MASS-BALANCE; HIGH-RESOLUTION; SHEET; MODEL; SHELF; RHEOLOGY; MOTION AB We have applied satellite radar interferometry methods to map the velocity field of the recently discovered Northeast Greenland Ice Stream. We have used these data in conjunction with ice thickness and accumulation data to determine that the ice stream is in balance within the measurement errors. We used control methods to invert a finite element model of ice sheet flow constrained by the data to infer the ice stream's basal shear stress distribution. Our results reveal that flow in a section of the downstream end has much in common with the streaming flow of the Ross Ice Streams of West Antarctica (e.g., a weak bed and fast flow in the presence of low driving stresses). For several hundred kilometers along the middle of the ice stream, the basal shear stress balances the driving stress. In the upstream area, where the ice stream is first visible in the velocity data, the bed appears to be weak, which may contribute to the initiation of the ice stream. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Bristol, Sch Geog Sci, Ctr Remote Sensing, Bristol BS8 1SS, Avon, England. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20740 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. RP CALTECH, Jet Prop Lab, MS 300-235,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ian@rgps1.jpl.nasa.gov; mark@essic.umd.edu; drm7@midway.uchicago.edu; j.l.bamber@bristol.ac.uk 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; MacAyeal, Douglas/0000-0003-0647-6176 NR 34 TC 42 Z9 42 U1 1 U2 35 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 34021 EP 34034 DI 10.1029/2001JD900087 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800048 ER PT J AU Fahnestock, MA Joughin, I Scambos, TA Kwok, R Krabill, WB Gogineni, S AF Fahnestock, MA Joughin, I Scambos, TA Kwok, R Krabill, WB Gogineni, S TI Ice-stream-related patterns of ice flow in the interior of northeast Greenland SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SATELLITE RADAR INTERFEROMETRY; DIGITAL ELEVATION MODELS; WEST ANTARCTICA; SHEET; ACCURACY; DYNAMICS; MARGINS; IMAGERY; BALANCE; ONSET AB Ice flow in the interior of the NE quadrant of the Greenland ice sheet is focused on the large ice stream draining the north side of the summit dome. The rapid ice flow in the stream is apparent in the surface features in the stream and at the margins, in the broad scale topography that drives ice flow, and in satellite-derived ice motion information. The patterns of ice flow in the upper half of the stream are remarkable for their level of organization, simple geometry, and effects on local surface topography. The stream begins less than 100 kin from the ice divide as a current 15 km wide and then broadens symmetrically downstream by the addition of ice from the sides to a width of more than 60 km. Elevation data and visible-band imagery show that the stream has marginal troughs tens of meters deep in its upper reach which are coincident with regions of high shear strain rate. The topography of the margins and undulating surface of the stream is generated by the ice flow; the surface undulations in the stream are fixed in location and shape over the 5 year period from 1994 to 1999. The enhanced flow presents a challenge for researchers trying to understand the history of ice discharge from a significant area in the interior of the ice sheet. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Univ Kansas, Radar Syst & Remote Sensing Lab, Lawrence, KS 66045 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, CIRES, Natl Snow & Ice Data Ctr, Boulder, CO 80309 USA. NASA, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, 2207 Comp & Space Sci Bldg, College Pk, MD 20742 USA. EM mark@essic.umd.edu; ian@rgps1.jpl.nasa.gov; ron@radar-sci.jpl.nasa.gov; gogineni@ittc.ukans.edu RI Kwok, Ron/A-9762-2008; Scambos, Ted/B-1856-2009; Joughin, Ian/A-2998-2008; Fahnestock, Mark/N-2678-2013 OI Kwok, Ron/0000-0003-4051-5896; Joughin, Ian/0000-0001-6229-679X; NR 24 TC 15 Z9 15 U1 0 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 34035 EP 34045 DI 10.1029/2001JD900194 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800049 ER PT J AU Walter, BP Heimann, M Matthews, E AF Walter, BP Heimann, M Matthews, E TI Modeling modern methane emissions from natural wetlands 1. Model description and results SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ABRUPT CLIMATE-CHANGE; ATMOSPHERIC METHANE; ROOT DISTRIBUTIONS; GLACIAL PERIOD; GROWTH-RATE; POLAR ICE; PEATLANDS; FLUX; SIMULATION; FLOODPLAIN AB Methane is an important greenhouse gas which contributes about 22% to the present greenhouse effect. Natural wetlands currently constitute the biggest methane source and were the major source in preindustrial times. Wetland emissions depend highly on the climate, i.e., on soil temperature and water table. To investigate the response of methane emissions from natural wetlands to climate variations, a process-based model that derives methane emissions from natural wetlands as a function of soil temperature, water table, and net primary productivity is used. For its application on the global scale, global data sets for all model parameters are generated. In addition, a simple hydrologic model is developed in order to simulate the position of the water table in wetlands. The hydrologic model is tested against data from different wetland sites, and the sensitivity of the hydrologic model to changes in precipitation is examined. The global methane-hydrology model constitutes a tool to study temporal and spatial variations in methane emissions from natural wetlands. The model is applied using high-frequency atmospheric forcing fields from ECMWF reanalyses of the period from 1982 to 1993. We calculate global annual methane emissions from wetlands to be 260 Tg yr(-1). Twenty-five percent of these methane emissions originate from wetlands north of 30degreesN. Only 60% of the produced methane is emitted, while the rest is reoxidized. A comparison of zonal integrals of simulated global wetland emissions and results obtained by an inverse modeling approach shows good agreement. In a test with data from two wetlands the seasonality of simulated and observed methane emissions agrees well. C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Max Planck Inst Biogeochem, Jena, Germany. RP Columbia Univ, NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM bwalter@giss.nasa.gov RI Heimann, Martin/H-7807-2016 OI Heimann, Martin/0000-0001-6296-5113 NR 55 TC 142 Z9 151 U1 7 U2 49 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 34189 EP 34206 DI 10.1029/2001JD900165 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800061 ER PT J AU Walter, BP Heimann, M Matthews, E AF Walter, BP Heimann, M Matthews, E TI Modeling modern methane emissions from natural wetlands 2. Interannual variations 1982-1993 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CH4 GROWTH-RATE; ATMOSPHERIC METHANE; NORTHERN-HEMISPHERE; TEMPERATURE-CHANGES; DRAMATIC DECREASE; TRANSPORT MODEL; RICE FIELDS; SENSITIVITY; CLIMATE; METHANOGENESIS AB A global run of a process-based methane model [Walter et al., this issue] is performed using high-frequency atmospheric forcing fields from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses of the period from 1982 to 1993. Modeled methane emissions show high regional, seasonal, and interannual variability. Seasonal cycles of methane emissions are dominated by temperature in high-latitude wetlands, and by changes in the water table in tropical wetlands. Sensitivity tests show that globally, +/-1degreesC changes in temperature lead to 20% changes in methane emissions from wetlands. Uniform changes of 20% in precipitation alter methane emissions by about +/-8%. Limitations in the model are analyzed and the effects of sub-grid-scale variations in model parameters and errors in the input data are examined. Simulated interannual variations in methane emissions from wetlands are compared to observed atmospheric growth rate anomalies. Our model simulation results suggest that contributions from sources other than wetlands and/or the sinks are more important in the tropics than north of 30degreesN. In high northern latitudes it seems that a large part of the observed interannual variations can be explained by variations in wetland emissions. Our results also suggest that reduced wetland emissions played an important role in the observed negative methane growth rate anomaly in 1992. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Max Planck Inst Biogeochem, Jena, Germany. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM bwalter@giss.nasa.gov RI Heimann, Martin/H-7807-2016 OI Heimann, Martin/0000-0001-6296-5113 NR 57 TC 79 Z9 84 U1 4 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 27 PY 2001 VL 106 IS D24 BP 34207 EP 34219 DI 10.1029/2001JD900164 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 522DE UT WOS:000173879800062 ER PT J AU Shepard, MK Campbell, BA Bulmer, MH Farr, TG Gaddis, LR Plaut, JJ AF Shepard, MK Campbell, BA Bulmer, MH Farr, TG Gaddis, LR Plaut, JJ TI The roughness of natural terrain: A planetary and remote sensing perspective SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID RADAR DATA; SURFACE; SCATTERING; TOPOGRAPHY; MAGELLAN; VENUS; SPECTRA; DESERT; FIELD AB We examine the various methods and parameters in common use for quantifying and reporting surface topographic "roughness." It is shown that scale-dependent roughness parameters are almost always required, though not widely used. We suggest a method of standardizing the parameters that are computed and reported so that topographic data gathered by different workers using different field techniques can be directly and easily intercompared. We illustrate the proposed method by analyzing topographic data from 60 different surfaces gathered by five different groups and examine the information for common features. We briefly discuss the implications of our analysis for studies of planetary surface roughness, lander safety, and radar remote sensing modeling and analysis. C1 Bloomsburg Univ Penn, Dept Geog & Geosci, Bloomsburg, PA 17815 USA. Smithsonian Inst, Natl Air & Space Museum, Ctr Earth & Planetary Studies, Washington, DC 20560 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. US Geol Survey, Flagstaff, AZ 86001 USA. RP Shepard, MK (reprint author), Bloomsburg Univ Penn, Dept Geog & Geosci, 400 E 2nd St, Bloomsburg, PA 17815 USA. OI Farr, Thomas/0000-0001-5406-2096 NR 31 TC 123 Z9 131 U1 2 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 32777 EP 32795 DI 10.1029/2000JE001429 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000001 ER PT J AU Zhang, KQ Ingersoll, AP Kass, DM Pearl, JC Smith, MD Conrath, BJ Haberle, RM AF Zhang, KQ Ingersoll, AP Kass, DM Pearl, JC Smith, MD Conrath, BJ Haberle, RM TI Assimilation of Mars Global Surveyor atmospheric temperature data into a general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID THERMAL EMISSION SPECTROMETER; TES OBSERVATIONS; AEROBRAKING AB We examined the observed temperature data from Thermal Emission Spectrometer (TES) between heliocentric longitude L-s = 141degrees and 146degrees (similar to10 Martian days in northern summer) during the mapping phase, then compared them with the simulated results using the NASA/Ames Mars general circulation model. Both show a strong polar vortex at the winter pole, higher equatorial temperatures near the ground and larger tropospheric lapse rates during daytime than at night. However, the simulation is colder than the observation at the bottom and top of the atmosphere and warmer in the middle. The highest wave activities are found in the polar front in both the simulations and the observations, but it is at a much higher altitude in the former. Experiments show that larger dust opacity improves the temperature field in the lower atmospheric levels. Using a steady state Kalman filter, we attempted to obtain a model state that is consistent with the observations. The assimilation did achieve better agreement with the observations overall, especially over the north pole. However, it is hard to make any further improvement. Dust opacity is the key factor in determining the temperature field; correcting temperature alone improves the spatial and temporal variations, it degrades the mean state in the south pole. Assimilation cannot improve the simulation further, unless more realistic dust opacity and its vertical profile are considered. C1 CALTECH, Jet Prop Lab, Ocean Sci Element, Div Geol & Planetary Sci, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Zhang, KQ (reprint author), CALTECH, Jet Prop Lab, Ocean Sci Element, Div Geol & Planetary Sci, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Smith, Michael/C-8875-2012 NR 11 TC 9 Z9 9 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 32863 EP 32877 DI 10.1029/2000JE001330 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000008 ER PT J AU Bills, BG Nerem, RS AF Bills, BG Nerem, RS TI Mars topography: Lessons learned from spatial and spectral domain comparisons of Mars Orbiter Laser Altimeter and US Geological Survey data SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HARMONIC-ANALYSIS; GLOBAL SURVEYOR; EARTH; VENUS; MODEL AB The topography of Mars has been mapped several times by a variety of techniques. We compare the recent Mars Orbiter Laser Altimeter version with the earlier U.S. Geological Survey compilation of photogrammetry and Earth-based radar. We compare them in terms of their respective representations on 1degreesx 1degrees grids, though both data sets contain substantially higher spatial resolution. We find that the differences between the two Mars topography models, though locally quite large. are generally quite small. The difference variance is 4% of the data variance. The difference between the two models is also quite notably anisotropic, with substantially more variation north-south than east-west. The variance in the difference between the models is a very small fraction of the data variance at the longest wavelengths and approaches a constant value of (similar to)30% at harmonic degrees above 20. C1 Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. Univ Colorado, Dept Aerosp Engn Sci, Colorado Ctr Astrodynam Res, Boulder, CO 80309 USA. RP Bills, BG (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. RI Bills, Bruce/C-1156-2008 NR 35 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 32915 EP 32925 DI 10.1029/2000JE001279 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000012 ER PT J AU Dohm, JM Ferris, JC Baker, VR Anderson, RC Hare, TM Strom, RG Barlow, NG Tanaka, KL Klemaszewski, JE Scott, DH AF Dohm, JM Ferris, JC Baker, VR Anderson, RC Hare, TM Strom, RG Barlow, NG Tanaka, KL Klemaszewski, JE Scott, DH TI Ancient drainage basin of the Tharsis region, Mars: Potential source for outflow channel systems and putative oceans or paleolakes SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID VALLES MARINERIS; THAUMASIA REGION; TECTONIC HISTORY; NORTHERN PLAINS; GROUND ICE; EVOLUTION; PROVINCE; GEOLOGY; CONSTRAINTS; PLATEAU AB Paleotopographic reconstructions based on a synthesis of published geologic information and high-resolution topography, including topographic profiles, reveal the potential existence of an enormous drainage basin/aquifer system in the eastern part of the Tharsis region during the Noachian Period. Large topographic highs formed the margin of the gigantic drainage basin. Subsequently, lavas, sediments, and volatiles partly infilled the basin, resulting in an enormous and productive regional aquifer. The stacked sequences of water-bearing strata were then deformed locally and, in places, exposed by magmatic-driven uplifts, tectonic deformation, and erosion. This basin model provides a potential source of water necessary to carve the large outflow channel systems of the Tharsis and surrounding regions and to contribute to the formation of putative northern-plains ocean(s) and/or paleolakes. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cent Florida, Dept Phys, Robinson Observ, Orlando, FL 32816 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Univ Arizona, Dept Planetary Sci, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Dohm, JM (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. EM jmd@hwr.arizona.edu RI Dohm, James/A-3831-2014; OI Hare, Trent/0000-0001-8842-389X NR 69 TC 115 Z9 116 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 32943 EP 32958 DI 10.1029/2000JE001468 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000014 ER PT J AU Anderson, JD Jacobson, RA Lau, EL Moore, WB Schubert, G AF Anderson, JD Jacobson, RA Lau, EL Moore, WB Schubert, G TI Io's gravity field and interior structure SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID DIFFERENTIATED INTERNAL STRUCTURE; GALILEO-ENCOUNTERS; LITHOSPHERE; INFERENCES; CALLISTO; SHAPE AB Radio Doppler data generated by the Deep Space Network (DSN) from four encounters of the Galileo spacecraft with Io, Jupiter's innermost Galilean satellite, are used to infer Io's gravitational quadrupole moments. By combining the four flybys into a single solution for the gravity field, the response of Io to the second degree tidal and rotational potentials is accurately determined. This is characterized by the value of the second degree potential Love number k(2) = 1.2924 +/- 0.0027. We construct interior models that satisfy constraints imposed by the mean radius R = 1821.6 +/- 0.5 km, the mean density (p) over bar = 3527.8 +/- 2.9 kg/m(3), and the normalized axial moment of inertia C/M R-2 = 0.37685 +/- 0.00035. The gravitationally derived figure of Io has principal axes (c < b < a) a = 1830.0 +/- 0.5 km, b = 1819.2 +/- 0.5 km, and c = 1815.6 +/- 0.5 km, consistent with the shape determined by imaging. Gravitational and other data strongly suggest that Io is in hydrostatic equilibrium. In this case, models of Io's interior density show that Io almost certainly has a metallic core with a radius between 550 and 900 km for an Fe-FeS core or between 350 and 650 km for an Fe core. Io is also likely to have a crust and a partially molten asthenosphere, but their thicknesses cannot be separately or uniquely determined from the gravitational data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Anderson, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-420, Pasadena, CA 91109 USA. NR 24 TC 60 Z9 61 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 32963 EP 32969 DI 10.1029/2000JE001367 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000016 ER PT J AU Matson, DL Johnson, TV Veeder, GJ Blaney, DL Davies, AG AF Matson, DL Johnson, TV Veeder, GJ Blaney, DL Davies, AG TI Upper bound on Io's heat flow SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SILICATE VOLCANISM; THERMAL EMISSION; INFRARED OBSERVATIONS; TEMPERATURE; CONSTRAINTS AB Analysis of the temperatures and areas of Io's thermal anomalies yields an upper bound on the total heat flow. An extended distribution function allows an assessment of the heat flow from undetected, cooler (but larger) anomalies and predicts a limiting temperature of similar to90-95 K for the surface. This value is in agreement with measured Voyager infrared interferometer spectrometer and Galileo Photo-Polarimeter Radiometer nighttime "minimum temperatures." In addition, the lack of dependence on both latitude and time of night for these observed temperatures can be explained by cooling lavas on a global scale. We consider the extreme case that Io may be covered completely by lava in various stages of cooling to the exclusion of any thermally passive 'background' (excepting the few high mountains). Such a distribution of volcanic thermal anomalies up to the size of Io itself yields the first upper bound for heat flow, 13.5 W m(-2). This corresponds to a total global, radiated power of 5.6 X 10(14) W. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matson, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Code 264-441, Pasadena, CA 91109 USA. NR 33 TC 12 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33021 EP 33024 DI 10.1029/2000JE001374 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000021 ER PT J AU Keszthelyi, L McEwen, AS Phillips, CB Milazzo, M Geissler, P Turtle, EP Radebaugh, J Williams, DA Simonelli, DP Breneman, HH Klaasen, KP Levanas, G Denk, T AF Keszthelyi, L McEwen, AS Phillips, CB Milazzo, M Geissler, P Turtle, EP Radebaugh, J Williams, DA Simonelli, DP Breneman, HH Klaasen, KP Levanas, G Denk, T CA Galileo SSI Team TI Imaging of volcanic activity on Jupiter's moon Io by Galileo during the Galileo Europa Mission and the Galileo Millennium Mission. SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED MAPPING SPECTROMETER; LAVA FLOW-FIELD; SILICATE VOLCANISM; HOT-SPOTS; THERMAL EMISSION; KILAUEA VOLCANO; TEMPERATURE; MODELS; ERUPTIONS; PLUME AB The Solid-State Imaging (SSI) instrument provided the first high- and medium-resolution views of Io as the Galileo spacecraft closed in on the volcanic body in late 1999 and early 2000. While each volcanic center has many unique features, the majority can be placed into one of two broad categories. The "Promethean" eruptions, typified by the volcanic center Prometheus, are characterized by long-lived steady eruptions producing a compound flow field emplaced in an insulating manner over a period of years to decades. In contrast, "Pillanian" eruptions are characterized by large pyroclastic deposits and short-lived but high effusion rate eruptions from fissures feeding open-channel or open-sheet flows. Both types of eruptions commonly have similar to100-km-tall, bright, SO2-rich plumes forming near the flow fronts and smaller deposits of red material that mark the vent for the silicate lavas. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Deutsch Zentrum Luft & Raumfahrt, Inst Planetenerkung, D-12489 Berlin, Germany. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Keszthelyi, L (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. RI Turtle, Elizabeth/K-8673-2012 OI Turtle, Elizabeth/0000-0003-1423-5751 NR 60 TC 70 Z9 70 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33025 EP 33052 DI 10.1029/2000JE001383 PG 28 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000022 ER PT J AU Lopes, RMC Kamp, LW Doute, S Smythe, WD Carlson, RW McEwen, AS Geissler, PE Kieffer, SW Leader, FE Davies, AG Barbinis, E Mehlman, R Segura, M Shirley, J Soderblom, LA AF Lopes, RMC Kamp, LW Doute, S Smythe, WD Carlson, RW McEwen, AS Geissler, PE Kieffer, SW Leader, FE Davies, AG Barbinis, E Mehlman, R Segura, M Shirley, J Soderblom, LA TI Io in the near infrared: Near-Infrared Mapping Spectrometer (NIMS) results from the Galileo flybys in 1999 and 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HOT-SPOTS; ACTIVE VOLCANISM; TEMPERATURE; SSI; SURFACE; SULFUR; MODEL; PLUME AB Galileo's Near-Infrared Mapping Spectrometer (NIMS) observed to during the spacecraft's three flybys in October 1999, November 1999, and February 2000. The observations, which are summarized here, were used to map the detailed thermal structure of active volcanic regions and the surface distribution Of SO2 and to investigate the origin of a yet unidentified compound showing an absorption feature at similar to1 mum. We present a summary of the observations and results, focusing on the distribution of thermal emission and Of SO2 deposits. We find high eruption temperatures, consistent with ultramafic volcanism, at Pele. Such temperatures may be present at other hot spots, but the hottest areas may be too small for those temperatures to be detected at the spatial resolution of our observations. Loki is the site of frequent eruptions, and the low thermal emission may represent lavas cooling on the caldera's surface or the cooling crust of a lava lake. High-resolution spectral observations of Emakong caldera show thermal emission and SO2 within the same pixels, implying that patches of SO2 frost and patches of cooling lavas or sulfur flows are present within a few kilometers from one another. Thermal maps of Prometheus and Amirani show that these two hot spots are characterized by long lava flows. The thermal profiles of flows at both locations are consistent with insulated flows, with the Amirani flow field having more breakouts of fresh lava along its length. Prometheus and Amirani each show a white ring at visible wavelengths, while SO2 distribution maps show that the highest concentration of SO2 in both ring deposits lies outside the white portion. Visible measurements at high phase angles show that the white deposit around Prometheus extends into the SO2 ring. This suggests that the deposits are thin and that compositional or grain size variations may occur in the radial direction. SO2 mapping of the Chaac region shows that the interior of a caldera adjacent to Chaac has almost pure SO2. The deposit appears to be topographically controlled, suggesting a possible origin by liquid flow. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNRS, Lab Planetol Grenoble, F-38041 Grenoble 9, France. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. SW Kieffer Sci Consulting Inc, Bolton, ON L7E 5T4, Canada. Univ Calif Los Angeles, IGPP, Los Angeles, CA 90095 USA. US Geol Survey, Flagstaff, AZ 86001 USA. RP Lopes, RMC (reprint author), CALTECH, Jet Prop Lab, MS 183-601,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 42 TC 63 Z9 63 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33053 EP 33078 DI 10.1029/2000JE001463 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000023 ER PT J AU Davies, AG Keszthelyi, LP Williams, DA Phillips, CB McEwen, AS Lopes, RMC Smythe, WD Kamp, LW Soderblom, LA Carlson, RW AF Davies, AG Keszthelyi, LP Williams, DA Phillips, CB McEwen, AS Lopes, RMC Smythe, WD Kamp, LW Soderblom, LA Carlson, RW TI Thermal signature, eruption style, and eruption evolution at Pele and Pillan on Io SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED MAPPING SPECTROMETER; LAVA FLOWS; HOT-SPOTS; SILICATE VOLCANISM; ACTIVE VOLCANISM; SOUTH-AFRICA; GALILEO; TEMPERATURE; EMISSION; SSI AB The Galileo spacecraft has been periodically monitoring volcanic activity on Io since June 1996, making it possible to chart the evolution of individual eruptions. We present results of coanalysis of Near-Infrared Mapping Spectrometer (NIMS) and solid-state imaging (SSI) data of eruptions at Pete and Pillan, especially from a particularly illuminating data set consisting of mutually constraining, near-simultaneous NIMS and SSI observations obtained during orbit C9 in June 1997. The observed thermal signature from each hot spot, and the way in which the thermal signature changes with time, tightly constrains the possible styles of eruption. Pete and Pillan have very different eruption styles. From September 1996 through May 1999, Pele demonstrates an almost constant total thermal output, with thermal emission spectra indicative of a long-lived, active lava lake. The NIMS Pillan data exhibit the thermal signature of a "Pillanian" eruption style, a large, vigorous eruption with associated open channel, or sheet flows, producing an extensive flow field by orbit C10 in September 1997. The high mass eruption rate, high liquidus temperature (at least 1870 K) eruption at Pillan is the best candidate so far for an active ultramalic (magnesium-rich, "komatiitic") flow on Io, a style of eruption never before witnessed. The thermal output per unit area from Pillan is, however, consistent with the emplacement of large, open-channel flows. Magma temperature at Pele is greater than or equal to1600 K. If the magma temperature is 1600 K, it suggests a komatiitic-basalt composition. The power output from Pele is indicative of a magma volumetric eruption rate of similar to250 to 340 m(3) s(-1). Although the Pele lava lake is considerably larger than its terrestrial counterparts, the power and mass fluxes per unit area are similar to active terrestrial lava lakes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. US Geol Survey, Branch Astrogeol, Flagstaff, AZ 86001 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RP Davies, AG (reprint author), CALTECH, Jet Prop Lab, MS 183-601,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 50 TC 73 Z9 73 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33079 EP 33103 DI 10.1029/2000JE001357 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000024 ER PT J AU Williams, DA Davies, AG Keszthelyi, LP Greeley, R AF Williams, DA Davies, AG Keszthelyi, LP Greeley, R TI The summer 1997 eruption at Pillan Patera on Io: Implications for ultrabasic lava flow emplacement SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID WESTERN-AUSTRALIA; SOUTH-AFRICA; KOMATIITE LAVAS; GREENSTONE-BELT; KILAUEA VOLCANO; GLOBAL COLOR; GALILEO; CRYSTALLIZATION; TEMPERATURES; KAMBALDA AB Galileo data and numerical modeling were used to investigate the summer 1997 eruption at Pillan Patera on Io. This event, now defined as "Pillanian" eruption style [Keszthelyi et al., this issue], included a high-temperature (>1600degreesC), possibly ultrabasic, 140-km-high plume eruption that deposited dark, or-thopyroxene-rich pyroclastic material over >125,000 km(2), followed by emplacement of dark flow-like material over >3100 km(2) to the north of the caldera. We estimate that the high-temperature, energetic episode of this eruption had a duration of 52-167 days between May and September 1997, with peak eruption temperatures around June 28, 1997. Galileo 20 in pixel(-1) images of part of the Pillan flow field show a widespread, rough, pitted surface that is unlike any flow surface we have seen before. We suggest that this surface may have resulted from (1) a fractured lava crust formed during rapid, low-viscosity lava surging, perhaps including turbulent flow emplacement; (2) disruption of the lava flow by explosive interaction with a volatile-rich substrate; or (3) a combination of I and 2 with or without accumulation of pyroclastic materials on the surface. Well-developed flow lobes are observed, suggesting that this is a relatively distal part of the flow field. Shadow measurements at flow margins indicate a thickness of similar to8-10 m. We have modeled the emplacement of putative ultrabasic flows from the summer 1997 Pillan eruption using constraints from new Galileo data. Results suggest that either laminar sheet flows or turbulent channelized flows could have traveled 50-150 km on a flat, unobstructed surface, which is consistent with the estimated length of the Pillan flow field (-60 km). Our modeling suggests low thermal erosion rates (<0.1 m d(-1)), and that the formation of deep (>20 m) erosion channels was unlikely, especially distal to the source. We calculate a volumetric flow rate of similar to2-7 x 10(3) m(3) s(-1), which is greater than those for typical Mauna Loa/Kilauea flows but comparable to those for the (1783) Laki eruption and the inferred flow rates of the Roza flows in the Columbia River flood basalts. The differences in ultrabasic eruption styles on Earth and Io appear to be controlled by the different eruption environments: Plumes at sites of ultrabasic eruptions on Io suggest strong magma-volatile interactions on a low-gravity body lacking an atmosphere, whereas the geology at sites of komatiite eruptions on Earth suggest mostly submarine emplacement of thick flows with a pronounced lack of subaerial explosive activity. C1 Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Williams, DA (reprint author), Arizona State Univ, Dept Geol Sci, Box 871404, Tempe, AZ 85287 USA. NR 63 TC 43 Z9 43 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33105 EP 33119 DI 10.1029/2000JE001339 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000025 ER PT J AU Howell, RR Spencer, JR Goguen, JD Marchis, F Prange, R Fusco, T Blaney, DL Veeder, GJ Rathbun, JA Orton, GS Grocholski, AJ Stansberry, JA Kanner, GS Hege, EK AF Howell, RR Spencer, JR Goguen, JD Marchis, F Prange, R Fusco, T Blaney, DL Veeder, GJ Rathbun, JA Orton, GS Grocholski, AJ Stansberry, JA Kanner, GS Hege, EK TI Ground-based observations of volcanism on Io in 1999 and early 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INFRARED MAPPING SPECTROMETER; THERMAL EMISSION; SILICATE VOLCANISM; ACTIVE VOLCANISM; GALILEO; MODELS AB Ground-based observations of volcanism on Io during the period of the 1999 and early 2000 Galileo close flybys have detected several types of activity, providing information which complements the spacecraft observations. At Loki a brightening began between August 25 and September 9 and continued through February. On August 2 a major outburst was observed near (14degreesN, 74degreesW) whose brightness corresponds to an area of approximately 350 km(2) at a temperature of 1100 X. Observations of eruptions in late June (9906A) and in late November (9911A, at Tvashtar) provide temporal and photometric constraints on activity also seen by Galileo. High-resolution adaptive optics images provide further information on the fainter sources distributed across the surface. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Lowell Observ, Flagstaff, AZ 86001 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. European So Observ, Santiago 19, Chile. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Off Natl Etud & Rech Aerosp, F-92322 Chatillon, France. Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Howell, RR (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. RI Marchis, Franck/H-3971-2012 NR 18 TC 32 Z9 32 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33129 EP 33139 DI 10.1029/2000JE001382 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000027 ER PT J AU Williams, DA Greeley, R Lopes, RMC Davies, AG AF Williams, DA Greeley, R Lopes, RMC Davies, AG TI Evaluation of sulfur flow emplacement on Io from Galileo data and numerical modeling SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID SILICATE VOLCANISM; LAVA FLOWS; ACTIVE VOLCANISM; LIQUID SULFUR; POAS VOLCANO; COSTA-RICA; HOT-SPOTS; TEMPERATURE; SURFACE; SSI AB Galileo images of bright lava flows surrounding Emakong Patera have been analyzed and numerical modeling has been performed to assess whether these flows could have resulted from the emplacement of sulfur lavas on To. Images from the solid-state imaging (SSI) camera show that these bright, white to yellow Emakong flows are up to 370 km long and contain dark, sinuous features that are interpreted to be lava conduits, similar to300-500 m wide and >100 km long, Near-Infrared Mapping Spectrometer (NIMS) thermal emission data yield a color temperature estimate of 344 K +/- 60 K (less than or equal to131degreesC) within the Emakong caldera. We suggest that these bright flows likely resulted from either sulfur lavas or silicate lavas that have undergone extensive cooling, pyroclastic mantling, and/or alteration with bright sulfurous materials. The Emakong bright flows have estimated volumes of similar to250-350 km(3), similar to some of the smaller Columbia River Basalt flows. If the Emakong flows did result from effusive sulfur eruptions, then they are orders of magnitude greater in volume than any terrestrial sulfur flows. Our numerical modeling results show that sulfur lavas on Io could have been emplaced as turbulent flows, which were capable of traveling tens to hundreds of kilometers, consistent with the predictions of Sagan [1979] and Fink et al. [1983]. Our modeled flow distances are also consistent with the measured lengths of the Emakong channels and bright flows. Modeled thermal erosion rates are similar to1-4 m d(-1) for flows erupted at similar to140-180degreesC, which are consistent with the melting rates of Kieffer et al. [2000]. The Emakong channels could be thermal erosional in nature; however, the morphologic signatures of thermal erosion channels cannot be discerned from available images. There are planned Galileo flybys of To in 2001 which provide excellent opportunities to obtain high-resolution morphologic and color data of Emakong Patera. Such observations could, along with further modeling, provide additional information to better constrain whether sulfur lavas produced the Emakong flows. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RP Williams, DA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-601, Pasadena, CA 91109 USA. RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 63 TC 27 Z9 27 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33161 EP 33174 DI 10.1029/2000JE001340 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000029 ER PT J AU Turtle, EP Jaeger, WL Keszthelyi, LP McEwen, AS Milazzo, M Moore, J Phillips, CB Radebaugh, J Simonelli, D Chuang, F Schuster, P AF Turtle, EP Jaeger, WL Keszthelyi, LP McEwen, AS Milazzo, M Moore, J Phillips, CB Radebaugh, J Simonelli, D Chuang, F Schuster, P CA Galileo SSI Team TI Mountains on Io: High-resolution Galileo observations, initial interpretations, and formation models SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ACTIVE VOLCANISM; LITHOSPHERE; TOPOGRAPHY; SYSTEM; ORIGIN; HEAT; LO AB During three close flybys in late 1999 and early 2000 the Galileo spacecraft acquired new observations of the mountains that tower above to's surface. These images have revealed surprising variety in the mountains' morphologies. They range from jagged peaks several kilometers high to lower, rounded structures. Some are very smooth, others are covered by numerous parallel ridges. Many mountains have margins that are collapsing outward in large landslides or series of slump blocks, but a few have steep, scalloped scarps. From these observations we can gain insight into the structure and material properties of to's crust as well as into the erosional processes acting on to. We have also investigated formation mechanisms proposed for these structures using finite-element analysis. Mountain formation might be initiated by global compression due to the high rate of global subsidence associated with to's high resurfacing rate; however, our models demonstrate that this hypothesis lacks a mechanism for isolating the mountains. The large fraction (similar to40%) of mountains that are associated with paterae suggests that in some cases these features are tectonically related. Therefore we have also simulated the stresses induced in to's crust by a combination of a thermal upwelling in the mantle with global lithospheric compression and have shown that this can focus compressional stresses. If this mechanism is responsible for some of Io's mountains, it could also explain the common association of mountains with paterae. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. SETI Inst, Ctr Study Life Universe, Mt View, CA 94043 USA. DLR, Berlin, Germany. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Turtle, EP (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Turtle, Elizabeth/K-8673-2012 OI Turtle, Elizabeth/0000-0003-1423-5751 NR 35 TC 31 Z9 31 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33175 EP 33199 DI 10.1029/2000JE001354 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000030 ER PT J AU Moore, JM Sullivan, RJ Chuang, FC Head, JW McEwen, AS Milazzo, MP Nixon, BE Pappalardo, RT Schenk, PM Turtle, EP AF Moore, JM Sullivan, RJ Chuang, FC Head, JW McEwen, AS Milazzo, MP Nixon, BE Pappalardo, RT Schenk, PM Turtle, EP TI Landform degradation and slope processes on Io: The Galileo view SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MASS MOVEMENTS; SYSTEM; ATMOSPHERE; SATELLITES; TERRAINS; SURFACE; ORIGIN; MODEL; WATER; SO2 AB The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on Io. We recognize four major slope types observed on a number of intermediate resolution (similar to250 m pixel(-1)) images and several additional textures on very high resolution (similar to10 m pixel(-1)) images. Slopes and scarps on Io often show evidence of erosion, seen in the simplest form as alcove-carving slumps and slides at all scales. Many of the mass movement deposits on Io are probably mostly the consequence of block release and brittle slope failure. Sputtering plays no significant role. Sapping as envisioned by McCauley et al. [1979] remains viable. We speculate that alcove-lined canyons seen in one observation and lobed deposits seen along the bases of scarps in several locations may reflect the plastic deformation and "glacial" flow of interstitial volatiles (e.g., SO2) heated by locally high geothermal energy to mobilize the volatile. The appearance of some slopes and near-slope surface textures seen in very high resolution images is consistent with erosion from sublimation-degradation. However, a suitable volatile (e.g., H2S) that can sublimate fast enough to alter Io's youthful surface has not been identified. Disaggregation from chemical decomposition of solid S2O and other polysulfur oxides may conceivably operate on Io. This mechanism could degrade landforms in a manner that resembles degradation from sublimation, and at a rate that can compete with resurfacing. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. RP Moore, JM (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Turtle, Elizabeth/K-8673-2012 OI Turtle, Elizabeth/0000-0003-1423-5751 NR 44 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33223 EP 33240 DI 10.1029/2000JE001375 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000032 ER PT J AU Geissler, P McEwen, A Phillips, C Simonelli, D Lopes, RMC Doute, S AF Geissler, P McEwen, A Phillips, C Simonelli, D Lopes, RMC Doute, S TI Galileo imaging of SO2 frosts on Io SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; SULFUR-DIOXIDE; SURFACE; SCATTERING; REGOLITH; SPECTRUM; IMAGES; STATE AB Io's visible appearance changes dramatically with solar phase angle. The polar regions and some plume deposits near active volcanic centers become comparatively bright with increasing phase angle, while the equatorial band grows relatively dark. We suggest that the areas of Io that appear unusually bright at high phase are covered by thin frosts of SO2 that are transparent under normal illumination. A global disk-resolved photometric analysis indicates that the frosts exhibit more nearly isotropic or forwardscattering behavior and less opposition brightening than average Ionian materials. Comparison with Near-Infrared Mapping Spectrometer (NIMS) results suggests that these frosts have relatively strong 4.1 mum absorptions indicative of fine-grained SO2. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. SETI Inst, Ctr Study Life Universe, Mountain View, CA 94043 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. CNRS, Lab Planetol Grenoble, F-38041 Grenoble 9, France. RP Geissler, P (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM geissler@pirl.lpl.arizona.edu; mcewen@pirl.lpl.arizona.edu; phillips@seti.org; simonelli@cuspif.tn.cornell.edu; rlopes@isaac.jpl.nasa.gov; Sylvain.Doute@planeto.obs.ujf-grenoble.fr RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 45 TC 13 Z9 13 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33253 EP 33266 DI 10.1029/2000JE001361 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000034 ER PT J AU Domingue, D Allamandola, L AF Domingue, D Allamandola, L TI Introduction to the special section: Photolysis and radiolysis of outer solar system ices (PROSSI) SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Editorial Material C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Domingue, D (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33273 EP 33273 DI 10.1029/2001JE001503 PG 1 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000036 ER PT J AU Hudson, RL Moore, MH AF Hudson, RL Moore, MH TI Radiation chemical alterations in solar system ices: An overview SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; IRRADIATED WATER-ICE; INTERSTELLAR ICES; INFRARED-SPECTROSCOPY; ORGANIC-MOLECULES; CARBON-MONOXIDE; MU-M; COMETS; MIXTURES; SPECTRUM AB Many solar system objects, such as planets, satellites, rings, and comets, are known to either be made of ices or to have icy surfaces. Because these ices are subjected to radiation processing by keV-MeV ions and UV photons, their chemical and physical properties evolve over time. We have employed a laboratory approach to investigate these radiolytic and photolytic changes. Ices, either pure or mixtures, are subjected to ionizing radiation and UV photons and then probed by IR spectroscopy. It has been found that radiolysis and photolysis destroy reactant molecules, synthesize new molecules, cause changes of phase in pure materials, and eject molecules from ices. Although our laboratory approach initially focused on product identification, it has become increasingly necessary to work toward a comprehensive understanding of ice chemistry. To this end, we describe recent radiation experiments on some of the most important solar system and interstellar ice molecules, such as H(2)O, CO, CO(2), and hydrocarbons. Chemical reactions are given to account for our observations, and these reactions include such general types as acid-base, electron-transfer, radical-radical combination, and H-atom addition. Comparisons of ion and UV processing are described for pure H(2)O and for two binary mixtures, H(2)O + CO(2) and NH(3) + CO. Predictions of molecular evolution in complex ices, both H(2)O- and N(2)-dominated, are made. Applications are described for cometary organic chemistry, ion processing in interstellar ices, and the recent discovery of H(2)O(2) on the surface of Europa. C1 Eckerd Coll, Dept Chem, St Petersburg, FL 33733 USA. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. RP Hudson, RL (reprint author), Eckerd Coll, Dept Chem, 4200 54th Ave, St Petersburg, FL 33733 USA. EM hudsonrl@eckerd.edu; ummhm@lepvax.gsfc.nasa.gov RI Hudson, Reggie/E-2335-2012 NR 43 TC 68 Z9 69 U1 0 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33275 EP 33284 DI 10.1029/2000JE001299 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000037 ER PT J AU Ehrenfreund, P d'Hendecourt, L Charnley, S Ruiterkamp, R AF Ehrenfreund, P d'Hendecourt, L Charnley, S Ruiterkamp, R TI Energetic and thermal processing of interstellar ices SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID TIME-DEPENDENT CHEMISTRY; DENSE MOLECULAR CLOUDS; ISO-SWS OBSERVATIONS; GRAIN MANTLES; GAS-PHASE; ISOTOPIC-SUBSTITUTION; INFRARED-SPECTROSCOPY; ABSORPTION FEATURES; VACUUM ULTRAVIOLET; MICRON ABSORPTION AB Our current knowledge on the chemical composition of interstellar ices is summarized with respect to the possible contribution of energetic photons and particles to their observed state. We describe the inventory of astronomical ices as determined by infrared observations from the Infrared Space Observatory (ISO) and laboratory spectroscopy. Sources of radiolysis, UV photolysis, and ice heating are then discussed in the context of the chemical state of material in dense molecular clouds and in protostellar cores. Through specific examples we show how energetic processing can explain the observed solid-state characteristics of several key molecules: CH(3)OH, CO(2), and OCN(-). We also discuss the gaseous and solid-state photochemistry of the first organic acid detected in interstellar ices, HCOOH. C1 Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, NL-2300 RA Leiden, Netherlands. Univ Paris 11, CNRS, Inst Astrophys Spatiale, F-91405 Orsay, France. NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. RP Ehrenfreund, P (reprint author), Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, POB 9513, NL-2300 RA Leiden, Netherlands. EM pascale@strw.leidenuniv.nl RI Appourchaux, Thierry/F-4692-2010 NR 63 TC 23 Z9 25 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33291 EP 33301 DI 10.1029/2000JE001349 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000039 ER PT J AU Roush, TL AF Roush, TL TI Physical state of ices in the outer solar system SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID NEAR-INFRARED SPECTROSCOPY; CHARGED-PARTICLE IRRADIATION; HUBBLE-SPACE-TELESCOPE; CENTAUR 1997 CU26; WATER-ICE; GALILEAN SATELLITES; EUROPAS SURFACE; H2O ICE; INTERSTELLAR; GANYMEDE AB Comparison of the identity and abundances of ices observed around protostars and those associated with comets clearly suggests that comets preserve the heritage of the interstellar materials that aggregrated to form them. However, the ability to identify these same species on icy satellites in the outer solar system is a complex function of the composition of the original ices, their subsequent thermal histories, and their exposure to various radiation environments. Our ability to identify the ices currently present on objects in the outer solar system relies upon observational and laboratory, and theoretical efforts. To date there is ample observational evidence for crystalline water ice throughout the outer solar system. In addition, there is growing evidence that amorphous ice may be present on some bodies. More volatile ices, e.g., N(2), CH(4), and CO, and other species, e.g., ammonia hydrate, are identified on objects lying at and beyond Uranus. Both photolysis and radiolysis play important roles in altering the original surfaces due to chemical reactions and erosion of the surface. Ultraviolet photolysis appears to dominate alteration of the upper few hundred angstroms, although sputtering of the surface can sometimes be a significantly competitive process, dominating on icy surfaces embedded in a strong planetary magnetospheric field. There is growing observational evidence that the by-products of photolysis and radiolysis, suggested on a theoretical basis, are present on icy surfaces. C1 NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. RP Roush, TL (reprint author), NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, MS 245-3, Moffett Field, CA 94035 USA. EM troush@mail.arc.nasa.gov NR 83 TC 40 Z9 40 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33315 EP 33323 DI 10.1029/2000JE001334 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000042 ER PT J AU Cottin, H Gazeau, MC Chaquin, P Raulin, F Benilan, Y AF Cottin, H Gazeau, MC Chaquin, P Raulin, F Benilan, Y TI Experimental and theoretical studies on the gas/solid/gas transformation cycle in extraterrestrial environments SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID ABSORPTION CROSS-SECTIONS; INTERSTELLAR ICE ANALOGS; LOW-TEMPERATURE; INFRARED OBSERVATIONS; ORGANIC-CHEMISTRY; TITANS ATMOSPHERE; CM(-1) REGION; COMET HALLEY; SPECTRA; PHOTOCHEMISTRY AB The ubiquity of molecular material in the universe, from hydrogen to complex organic matter, is the result of intermixed physicochemical processes that have occurred throughout history. In particular, the gas/solid/gas phase transformation cycle plays a key role in chemical evolution of organic matter from the interstellar medium to planetary systems. This paper focuses on two examples that are representative of the diversity of environments where such transformations occur in the Solar System: (1) the photolytic evolution from gaseous to solid material in methane containing planetary atmospheres and (2) the degradation of high molecular weight compounds into gas phase molecules in comets. We are currently developing two programs which couple experimental and theoretical studies. The aim of this research is to provide data necessary to build models in order to better understand (1) the photochemical evolution of Titan's atmosphere, through a laboratory program to determine quantitative spectroscopic data on long carbon chain molecules (polyynes) obtained in the SCOOP program (French acronym for Spectroscopy of Organic Compounds Oriented for Planetology), and (2) the extended sources in comets, through a laboratory program of quantitative studies of photochemical and thermal degradation processes on relevant polymers (e.g., Polyoxymethylene) by the SEMAPhOrE Cometaire program (French acronym for Experimental Simulation and Modeling Applied to Organic Chemistry in Cometary Environment). C1 Univ Paris 07, Lab Interuniv Syst Atmospher, CNRS, UMR 7583, F-94010 Creteil, France. Univ Paris 12, Lab Interuniv Syst Atmospher, CNRS, UMR 7583, F-94010 Creteil, France. Univ Paris 06, Chim Theor Lab, F-75005 Paris, France. RP Cottin, H (reprint author), NASA, Goddard Space Flight Ctr, Astrochem Branch, Code 691, Greenbelt, MD 20770 USA. EM hcottin@lepvax.gsfc.nasa.gov; Gazeau@lisa.univ-paris12.fr; Raulin@lisa.univ-paris12.fr; Benilan@lisa.univ-paris12.fr RI Cottin, Herve/H-5654-2013 OI Cottin, Herve/0000-0001-9170-5265 NR 38 TC 6 Z9 6 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33325 EP 33332 DI 10.1029/2000JE001319 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000043 ER PT J AU Delzeit, L Blake, D AF Delzeit, L Blake, D TI A characterization of crystalline ice nanoclusters using transmission electron microscopy SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID NUCLEATION RATES; INFRARED-SPECTRA; SURFACE; CLUSTERS; WATER; SCATTERING AB The preparation of crystalline ice nanoclusters from a mixture of 0.5-2.0% water vapor in N-2 carrier gas produces clusters that range in diameter from similar to10 to several hundred nanometers, with a mode of 15-30 rim. By varying the percent water vapor in the mixture or the aliquot size, the average cluster size and the size distribution of the clusters can be controlled. If a second strong hydrogen-bonding molecule such as methanol is added to the mixture, the size distribution of the clusters is changed. The spherical shape of the crystalline ice nanoclusters observed in transmission electron microscopy (TEM) bright field imaging suggests that the clusters form from liquid droplets that crystallize upon further cooling. TEM dark field imaging of individual clusters reveals a structure in which crystalline domains are oriented one to another in mosaic fashion. This structural relationship appears to propagate from the centers of the clusters, indicating that nucleation and growth proceed from the centers outward. Water ice nanoclusters prepared in this way are useful analogs for ices from a variety of natural environments, including cold interstellar molecular clouds, comets, and terrestrial polar stratospheric clouds. The ice nanoclusters have a large surface area relative to their bulk that allows for the rapid reaction of the ice with other species present in the water-carrier gas mixture or deposited on the clusters subsequent to their formation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Delzeit, L (reprint author), NASA, Ames Res Ctr, MS 239-4, Moffett Field, CA 94035 USA. NR 15 TC 16 Z9 17 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33371 EP 33379 DI 10.1029/2000JE001288 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000047 ER PT J AU Gerakines, PA Moore, MH Hudson, RL AF Gerakines, PA Moore, MH Hudson, RL TI Energetic processing of laboratory ice analogs: UV photolysis versus ion bombardment SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INTERSTELLAR ICES; MIXTURES; METHANOL; COMETS AB We have the ability to perform both ultraviolet (UV) photolysis (primarily Lyman-alpha photons, average E approximate to 10.2 eV per photon) and ion irradiation (protons, E = 0.8 MeV) in the same experimental setup, with ices created under identical conditions. Here we present recent results on the UV and ion processing of ice mixtures at IS K of the composition H2O + CO2 + CH3OH (1: 1: 1) and H2O + CO2 + CH4 (1: 1: 1). H2O, CH3OH, CH4, and CO2 are all major components of ices in most astrophysical environments (whether interstellar, cometary, or planetary). Identifications and formation rates of products were measured. Results for photolyzed and irradiated ices are contrasted. We find that similar chemical products are observed in both cases and that rates of formation are equivalent for most of the major products. C1 NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Eckerd Coll, Dept Chem, St Petersburg, FL 33733 USA. RP Gerakines, PA (reprint author), Univ Alabama, Dept Phys, Astro & Solar Syst Phys Program, 1300 Univ Blvd,CH 310, Birmingham, AL 35294 USA. RI Gerakines, Perry/B-9705-2009; Hudson, Reggie/E-2335-2012; Gerakines, Perry/D-2226-2012 OI Gerakines, Perry/0000-0002-9667-5904 NR 11 TC 52 Z9 53 U1 3 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD DEC 25 PY 2001 VL 106 IS E12 BP 33381 EP 33385 DI 10.1029/2000JE001320 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 515GX UT WOS:000173488000048 ER PT J AU Ricca, A AF Ricca, A TI Heats of formation for Fe(CO)(n) (n=1-4) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GAUSSIAN-BASIS SETS; COUPLED-CLUSTER THEORY; MOLECULAR CALCULATIONS; ELECTRON CORRELATION; WAVE-FUNCTIONS; ENERGIES; ATOMS AB The dissociation energies of Fe(CO)(n) (n = 2-4) are computed using correlation consistent basis sets and the CCSD(T) approach. The dissociation energies are extrapolated to the CBS limit and are corrected for core-valence (CV), scalar relativistic, spin-orbit, zero-point, and thermal effects. Our iron carbonyl bond strengths agree with experiment within the respective error bars. We use our dissociations energies at 298 K to obtain the heats of formation of Fe(CO)(n) (n = 1-4). (C) 2001 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. RP Ricca, A (reprint author), NASA, Ames Res Ctr, ELORET Corp, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 27 TC 14 Z9 14 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 21 PY 2001 VL 350 IS 3-4 BP 313 EP 317 DI 10.1016/S0009-2614(01)01308-2 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 507YG UT WOS:000173058400017 ER PT J AU Barnes, RA Eplee, RE Schmidt, GM Patt, FS McClain, CR AF Barnes, RA Eplee, RE Schmidt, GM Patt, FS McClain, CR TI Calibration of SeaWiFS. I. Direct techniques SO APPLIED OPTICS LA English DT Article ID ZONE COLOR SCANNER; RADIOMETRIC CALIBRATION; ATMOSPHERIC CORRECTION; OCEAN COLOR; LUNAR; MOON; SENSITIVITY; METHODOLOGY; RADIANCE; IMAGERY AB We present an overview of the calibration of the Sea-viewing Wide Field-of View Sensor (SeaWiFS) from its performance verification at the manufacturer's facility to the completion of its third year of on-orbit measurements. These calibration procedures have three principal parts: a prelaunch radiometric calibration that is traceable to the National Institute of Standards and Technology; the Transfer-to-Orbit Experiment, a set of measurements that determine changes in the instrument's calibration from its manufacture to the start of on-orbit operations; and measurements of the sun and the moon to determine radiometric changes on orbit. To our knowledge, SeaWiFS is the only instrument that uses routine lunar measurements to determine changes in its radiometric sensitivity. On the basis of these methods, the overall uncertainty in the SeaWiFS top-of-the-atmosphere radiances is estimated to be 4-5%. We also show the results of comparison campaigns with aircraft- and ground-based measurements, plus the results of an experiment, called the Southern Ocean Band 8 Gain Study. These results are used to check the calibration of the SeaWiFS bands. To date, they have not been used to change the instrument's prelaunch calibration coefficients. In addition to these procedures, SeaWiFS is a vicariously calibrated instrument for ocean-color measurements. In the vicarious calibration of the SeaWiFS visible bands, the calibration coefficients are modified to force agreement with surface truth measurements from the Marine Optical Buoy, which is moored off the Hawaiian Island of Lanai, This vicarious calibration is described in a companion paper. (C) 2001 Optical Society of America. C1 Sci Applicat Int Corp, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Off Global Carbon Studies, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Barnes, RA (reprint author), Sci Applicat Int Corp, Beltsville, MD 20705 USA. EM rbarnes@seawifs.gsfc.nasa.gov NR 43 TC 83 Z9 86 U1 1 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 2001 VL 40 IS 36 BP 6682 EP 6700 DI 10.1364/AO.40.006682 PG 19 WC Optics SC Optics GA 505MR UT WOS:000172917000017 PM 18364980 ER PT J AU Eplee, RE Robinson, WD Bailey, SW Clark, DK Werdell, PJ Wang, MH Barnes, RA McClain, CR AF Eplee, RE Robinson, WD Bailey, SW Clark, DK Werdell, PJ Wang, MH Barnes, RA McClain, CR TI Calibration of SeaWiFS. II. Vicarious techniques SO APPLIED OPTICS LA English DT Article ID ZONE COLOR SCANNER; WATER-LEAVING RADIANCE; ATMOSPHERIC CORRECTION; SPECTRAL REFLECTANCE; WHITECAPS; VALIDATION; ALGORITHM; SENSORS; IMAGERY; OCEANS AB We present an overview of the vicarious calibration of the Sea-Viewing Wide Field-of-view Sensor (SeaWiFS). This program has three components: the calibration of the near-infrared bands so that the atmospheric correction algorithm retrieves the optical properties of maritime aerosols in the open ocean; the calibration of the visible bands against in-water measurements from the Marine Optical Buoy (MOBY); and a calibration-verification program that uses comparisons between SeaWiFS retrievals and globally distributed in situ measurements of water-leaving radiances. This paper describes the procedures as implemented for the third reprocessing of the SeaWiFS global mission data set. The uncertainty in the near-infrared vicarious gain is 0.9%. The uncertainties in the visible-band vicarious gains are 0.3%, corresponding to uncertainties in the water-leaving radiances of approximately 3%. The means of the SeaWiFS/in situ matchup ratios for water-leaving radiances are typically within 5% of unity in Case 1 waters, while chlorophyll a ratios are within 1% of unity. SeaWiFS is the first ocean-color mission to use an extensive and ongoing prelaunch and postlaunch calibration program, and the matchup results demonstrate the benefits of a comprehensive approach. (C) 2001 Optical Society of America. C1 Sci Applicat Int Corp, Beltsville, MD 20705 USA. Futuretech Corp, Greenbelt, MD 20770 USA. Natl Environm Satellite Data & Informat Serv, Natl Ocean & Atmospher Adm, Camp Springs, MD 20746 USA. Sci Syst & Applicat Inc, Lanham, MD 21250 USA. Univ Maryland, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Eplee, RE (reprint author), Sci Applicat Int Corp, Beltsville, MD 20705 USA. EM eplee@calva1.gsfc.nasa.gov RI Wang, Menghua/F-5631-2010; Werdell, Jeremy/D-8265-2012; Bailey, Sean/D-3077-2017 OI Wang, Menghua/0000-0001-7019-3125; Bailey, Sean/0000-0001-8339-9763 NR 31 TC 88 Z9 90 U1 0 U2 6 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 2001 VL 40 IS 36 BP 6701 EP 6718 DI 10.1364/AO.40.006701 PG 18 WC Optics SC Optics GA 505MR UT WOS:000172917000018 PM 18364981 ER PT J AU Colina, L Borne, K Bushouse, H Lucas, RA Rowan-Robinson, M Lawrence, A Clements, D Baker, A Oliver, S AF Colina, L Borne, K Bushouse, H Lucas, RA Rowan-Robinson, M Lawrence, A Clements, D Baker, A Oliver, S TI Ultraluminous infrared galaxies: Mergers of sub-L* galaxies? SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : interactions; galaxies : nuclei; galaxies : starburst; infrared : galaxies; quasars : general ID QUASAR HOST GALAXIES; DEEP SUBMILLIMETER SURVEY; STAR-FORMATION; OPTICAL SPECTROSCOPY; IRAS GALAXIES; LUMINOUS QUASARS; HIGH-REDSHIFT; IMAGES; RESOLUTION; NUCLEAR AB A sample of 27 low-redshift, mostly cool, ultraluminous infrared galaxies (ULIRGs) has been imaged at 1.6 mum with the Hubble Space Telescope (HST) Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). The majority (67%) of the sample's galaxies are multiple-nucleus galaxies with projected separations of up to 17 kpc, and the rest of the sample (33%) are single-nucleus galaxies, as determined by the NICMOS angular resolution limit. The average observed, integrated (host + nucleus) H magnitude of our HST H sample ULIRGs is -24.3, slightly above that of an L* galaxy (M-H = 24.2), and 52% of the sample's galaxies have sub-L* luminosities. The ULIRGs in the HST H sample are not generated as a result of the merging of two luminous (i.e., greater than or equal toL*) spiral galaxies. Instead, the interactions and mergers occur in general between two, or in some cases more, less massive sub-L* (0.3-0.5L*) galaxies. Only one out of the 49 nuclei identified in the entire HST H sample has the properties of a bright quasar-like nucleus. On average, the brightest nuclei in the HST H sample galaxies (i.e., cool ULIRGs) are 1.2 mag fainter than warm ULIRGs and low-luminosity Bright Quasar Survey quasars (BQS QSOs) and 2.6 mag fainter than high-luminosity BQS QSOs. Since the progenitor galaxies involved in the merger are sub-L* galaxies, the mass of the central black hole in these ULIRGs would be only about (1-2) x 10(7) M-., if the bulge-to-black hole mass ratio of nearby galaxies holds for ULIRGs. The estimated mass of the central black hole is similar to that of nearby Seyfert 2 galaxies but at least 1 order of magnitude lower than the massive black holes thought to be located at the center of high-luminosity QSOs. Massive nuclear starbursts with constant star formation rates of 10-40 M-. yr(-1) could contribute significantly to the nuclear H-band flux and are consistent with the observed nuclear H-band magnitudes of the ULIRGs in the HST H sample. An evolutionary merging scenario is proposed for the generation of the different types of ULIRGs and QSOs on the basis of the masses of the progenitors involved in the merging process. According to this scenario, cool ULIRGs would be the end product of the merging of two or more low-mass (0.3L*-0.5L*) disk galaxies. Warm ULIRGs and low-luminosity QSOs would be generated by a merger involving intermediate-mass (0.5 L*) disk galaxies. Under this scenario, warm ULIRGs could still be the dust-enshrouded phases of UV-bright low-luminosity QSOs, but cool ULIRGs, which are most ULIRGs, would not evolve into QSOs. C1 UC, Fac Ciencias, CSIC, Inst Fis Cantabria, Santander 39005, Spain. NASA, Raytheon Informat Technol & Sci Serv, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BZ, England. Univ Edinburgh, Inst Astron, Royal Observ, Edinburgh EH9 3JZ, Midlothian, Scotland. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. Univ Sussex, CPES, Ctr Astron, Brighton BN1 9QJ, E Sussex, England. RP Colina, L (reprint author), UC, Fac Ciencias, CSIC, Inst Fis Cantabria, Santander 39005, Spain. EM colina@ifca.unican.es; borne@rings.gsfc.nasa.gov; bushouse@stsci.edu; lucas@stsci.edu; m.rrobinson@ic.ac.uk; a.lawrence@roe.ac.uk; david.clements@astro.cf.ac.uk; a.baker@astro.cf.ac.uk; S.Oliver@sussex.ac.uk NR 44 TC 44 Z9 45 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 546 EP 554 DI 10.1086/323945 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900008 ER PT J AU Blaes, O Hubeny, I Agol, E Krolik, JH AF Blaes, O Hubeny, I Agol, E Krolik, JH TI Non-LTE, relativistic accretion disk fits to 3C 273 and the origin of the Lyman limit spectral break SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : active; quasars : individual (3C 273) ID ACTIVE GALACTIC NUCLEI; MARGINALLY STABLE ORBIT; HUBBLE-SPACE-TELESCOPE; MASSIVE BLACK-HOLE; THEORETICAL SPECTRA; MAGNETIZED ACCRETION; CONTINUUM EMISSION; COMPTON-SCATTERING; ULTRAVIOLET; QUASARS AB We fit general relativistic, geometrically thin accretion disk models with non-LTE atmospheres to near-simultaneous multiwavelength data of 3C 273, extending from the optical to the far-ultraviolet. Our model fits show no flux discontinuity associated with a hydrogen Lyman edge, but they do exhibit a spectral break which qualitatively resembles that seen in the data. This break arises from relativistic smearing of Lyman emission edges which are produced locally at tens of gravitational radii in the disk. We discuss the possible effects of metal line blanketing on the model spectra, as well as the substantial Comptonization required to explain the observed soft X-ray excess. Our best-Dt accretion disk model underpredicts the near-ultraviolet emission in this source and also has an optical spectrum which is too red. We discuss some of the remaining physical uncertainties and suggest in particular that an extension of our models to the slim disk regime and/or including nonzero magnetic torques across the innermost stable circular orbit may help resolve these discrepancies. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. NASA, AURA, NOAO, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Blaes, O (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RI Agol, Eric/B-8775-2013 OI Agol, Eric/0000-0002-0802-9145 NR 59 TC 35 Z9 35 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 560 EP 568 DI 10.1086/324045 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900010 ER PT J AU Band, DL AF Band, DL TI The energy distribution of gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; methods : statistical AB The distribution of the apparent total energy emitted by a gamma-ray burst reflects not only the distribution of the energy actually released by the burst engine, but also the distribution of beaming angles. Using the observed energy fluences, the detection thresholds, and burst redshifts for three burst samples, I calculate the best-fit parameters for lognormal and power-law distributions of the apparent total energy. Two of the samples include a small number of bursts with spectroscopic redshifts, while the third sample has 220 bursts with redshifts determined by the proposed variability-luminosity correlation. I find different sets of parameter values for the three burst samples. The Bayesian odds ratio cannot distinguish between the two model distribution functions for the two smaller burst samples with spectroscopic redshifts, but does favor the lognormal distribution for the larger sample with variability-derived redshifts. The data do not rule out a distribution with a low-energy tail that is currently unobservable. I find that neglecting the burst detection threshold biases the fitted distribution to be narrower with a higher average value than the true distribution; this demonstrates the importance of determining and reporting the effective detection threshold for bursts in a sample. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Band, DL (reprint author), NASA, GLAST SSC, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 9 TC 5 Z9 5 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 582 EP 591 DI 10.1086/323956 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900012 ER PT J AU Grossan, B Gorjian, V Werner, M Ressler, M AF Grossan, B Gorjian, V Werner, M Ressler, M TI High-resolution mid-infrared images of the nucleus of M81 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (M81); galaxies : nuclei; infrared : galaxies ID ACTIVE GALACTIC NUCLEI; ENERGY-DISTRIBUTIONS; ELLIPTIC GALAXIES; BRIGHT GALAXIES; 4.85 GHZ; DISCOVERY; EMISSION; CATALOG; MICRONS; LINER AB We observed two nearby galaxies with potential or weak indications of nuclear activity, M32 and M81, with the MIRLIN mid-IR camera at N band (10.79 mum). M32 is not detected, but we give detailed measurements of the nucleus of M81. Our observations of M81 show a bright nuclear point source at N, and comparison to measurements made in the early 1970s gives an increase in nuclear flux of nearly a factor of 2. If the comparison is accurate, the nuclear mid-IR emission must ultimately be powered by a variable, compact source, similar to that in Seyfert galaxies and quasars. M81 has been classified in the literature as a low-luminosity LINER, not a pure Seyfert galaxy. Further, it has been suggested that this and other low-luminosity active galactic nuclei may have intrinsically different spectra than Seyfert galaxies and quasars. However, we find that the relative fluxes in the X-ray, mid-IR, and radio bands, all essentially unaffected by extinction and galaxy pollution, show a nuclear continuum remarkably like that of a bona Dde Seyfert galaxy or quasar. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grossan, B (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Inst Nucl & Particle Astrophys, 50-232,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM bruce@singu.lbl.gov; vg@coma.jpl.nasa.gov; mwerner@sirtfweb.jpl.nasa.gov; Michael.E.Ressler@jpl.nasa.gov NR 28 TC 11 Z9 11 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 687 EP 693 DI 10.1086/323948 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900020 ER PT J AU Tripp, TM Giroux, ML Stocke, JT Tumlinson, J Oegerle, WR AF Tripp, TM Giroux, ML Stocke, JT Tumlinson, J Oegerle, WR TI The ionization and metallicity of the intervening OVI absorber at z=0.1212 in the spectrum of H1821+643 SO ASTROPHYSICAL JOURNAL LA English DT Article DE intergalactic medium; quasars : absorption lines; quasars : individual (H1821+643) ID LY-ALPHA FOREST; SPECTROSCOPIC-EXPLORER OBSERVATIONS; TELESCOPE IMAGING SPECTROGRAPH; HOT INTERGALACTIC MEDIUM; ABSORPTION-LINE SYSTEMS; ON-ORBIT PERFORMANCE; X-RAY CONSTRAINTS; LOW-REDSHIFT; IONIZING-RADIATION; METAL ENRICHMENT AB We use high-resolution UV spectra of the radio-quiet quasar (QSO) H1821+643 (z(em) = 0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE), to study the ionization and metallicity of an intervening O VI absorption line system at z(abs) = 0.1212. This absorber has the following notable properties : (1) several galaxies are close to the sight line at the absorber redshift, including an actively star-forming galaxy at a projected distance of 144 h(75)(-1) kpc, (2) there is a complex cluster of H I Ly alpha absorption lines near the O VI redshift, including at least five components spread over a velocity range of similar to 700 km s(-1), (3) the strongest Ly alpha line in the cluster appears to be composed of a mildly saturated component with a typical b-value blended with a remarkably broad component with b approximate to 85 km s(-1), (4) the O VI absorption is not aligned with the strongest (saturated) H I absorption, but instead is well aligned with the very broad component, and (5) the only detected species (at the 4 sigma level) are O VI and H I, despite coverage of strong transitions of abundant elements (e.g., C II, CIII, and C IV). Based on these constraints, we find that the absorption line properties can be produced in collisionally ionized gas with 10(5.3) less than or equal to T less than or equal to 10(5.6) K and -1.8 less than or equal to [O/ H] less than or equal to -0.6. However, we find that photoionization is also viable if the path length l through the absorbing gas is long enough; simple photoionization models require 85 less than or equal to l less than or equal to 1900 kpc and -1.1 less than or equal to [O/H] less than or equal to -0.3. We briefly discuss how observations of X-ray absorption lines due to O VII and O VIII could be used, in principle, to break the ionization mechanism degeneracy, and we conclude with some comments regarding the nature of O VI absorbers. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Johns Hopkins Univ, Dept Phys & Astron, Bloomberg Ctr, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tripp, TM (reprint author), Princeton Univ Observ, Peyton Hall,Ivy Lane, Princeton, NJ 08544 USA. RI Oegerle, William/C-9070-2012 NR 90 TC 80 Z9 80 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 724 EP 735 DI 10.1086/323965 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900023 ER PT J AU Yanasak, NE Wiedenbeck, ME Mewaldt, RA Davis, AJ Cummings, AC George, JS Leske, RA Stone, EC Christian, ER von Rosenvinge, TT Binns, WR Hink, PL Israel, MH AF Yanasak, NE Wiedenbeck, ME Mewaldt, RA Davis, AJ Cummings, AC George, JS Leske, RA Stone, EC Christian, ER von Rosenvinge, TT Binns, WR Hink, PL Israel, MH TI Measurement of the secondary radionuclides Be-10, Al-26, Cl-36, Mn-54, and C-14 and implications for the galactic cosmic-ray age SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmic rays; Galaxy : general; Galaxy : halo; ISM : abundances ID PRODUCTION CROSS-SECTIONS; ADVANCED-COMPOSITION-EXPLORER; PROTON-INDUCED REACTIONS; ISOTOPIC COMPOSITION; LOW-ENERGY; ELEMENTS 6-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-29; VOYAGER MEASUREMENTS; INTERSTELLAR MATTER; NUCLIDE PRODUCTION; CONFINEMENT TIME AB We report on abundance measurements of Be-10, Al-26, Cl-36, and Mn-54 in the Galactic cosmic rays (GCRs) using the Cosmic-Ray Isotope Spectrometer (CRIS) instrument aboard the Advanced Composition Explorer spacecraft at energies from similar to 70 to similar to 400 MeV nucleon(-1). We also report an upper limit on the abundance of GCR C-14. The high statistical significance of these measurements allows the energy dependence of their relative abundances to be studied. A steady-state, leaky-box propagation model, incorporating observations of the local interstellar medium (ISM) composition and density and recent partial fragmentation cross section measurements, is used to interpret these abundances. Using this model, the individual galactic confinement times derived using data for each species are consistent with a unique confinement time value of tau (esc) = 15.0 +/- 1.6 Myr. The CRIS abundance measurements are consistent with propagation through an average ISM hydrogen number density n(H) = 0.34 +/- 0.04 H atoms cm(-3). The surviving fractions, f, for each radioactive species have been calculated. From predictions of the diffusion models of Ptuskin & Soutoul, the values of f indicate an interstellar cosmic-ray diffusion coefficient of D = (3.5 +/- 2.0) x 10(28) cm(2) s(-1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Washington Univ, St Louis, MO 63130 USA. RP Yanasak, NE (reprint author), Univ Georgia, Dept Psychol, Human Neuroimaging Facil, Athens, GA 30602 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 106 TC 89 Z9 89 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 768 EP 792 DI 10.1086/323842 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900026 ER PT J AU Guerrero, MA Miranda, LF Chu, YH Rodriguez, M Williams, RM AF Guerrero, MA Miranda, LF Chu, YH Rodriguez, M Williams, RM TI The constant-velocity highly collimated outflows of the planetary nebula He 2-90 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : jets and outflows; ISM : kinematics and dynamics; planetary nebulae : individual (He 2-90) ID HUBBLE-SPACE-TELESCOPE; KNOTTY OUTFLOW; BIPOLAR; MICROSTRUCTURES; SPECTROSCOPY; MYCN-18; OBJECTS; FLIERS; M-1-92; STARS AB We present high-dispersion echelle spectroscopic observations and a narrowband [N II] image of the remarkable jetlike features of He 2-90. They are detected in the echelle spectra in the H alpha and [N II] lines but not in other nebular lines. The [N II]/H alpha ratio is uniformly high, similar or equal to1. The observed kinematics reveals bipolar collimated outflows in the jetlike features and shows that the southeast (northwest) component expands toward (away from) the observer at a remarkably constant line-of-sight velocity, 26.0 +/- 0.5 km s(-1). The observed expansion velocity and the opening angle of the jetlike features are used to estimate an inclination angle of similar or equal to5 degrees with respect to the sky plane and a space expansion velocity of similar or equal to 290 km s(-1). The spectrum of the bright central nebula reveals a profusion of Fe lines and extended wings of the H alpha line, similar to those seen in symbiotic stars and some young planetary nebulae that are presumed to host a mass-exchanging binary system. If this is the case for He 2-90, the constant velocity and direction of the jets require a very stable dynamic system against precession and warping. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. INAOE, Puebla 72840, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Guerrero, MA (reprint author), Univ Illinois, Dept Astron, 1002 W Green St, Urbana, IL 61801 USA. OI Guerrero, Martin/0000-0002-7759-106X NR 27 TC 18 Z9 18 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 883 EP 888 DI 10.1086/324028 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900036 ER PT J AU Hyung, S Aller, LH Feibelman, WA Lee, SJ AF Hyung, S Aller, LH Feibelman, WA Lee, SJ TI Optical spectrum of the compact planetary nebula IC 5117 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; planetary nebulae : individual (IC 5117); plasmas ID AURORAL EMISSION-LINES; CO; ABUNDANCES; ENVELOPES; IC-5117; STARS AB High-resolution spectroscopic data of the very compact planetary nebula IC 5117 were obtained in optical wavelengths of 3700-10050 Angstrom with the Hamilton Echelle Spectrograph at the Lick Observatory and have been analyzed along with the International Ultraviolet Explorer UV archive data. Although a diagnostic diagram shows significant density and temperature fluctuations, our analysis indicates that the nebular gas may be represented by a homogeneous shell of extremely high-density gas, N-epsilon similar to 90,000 cm(-3). The average electron temperatures, e.g., indicated by the [O III] diagnostics, are around 12,000 K. We construct a photoionization model to represent most of the observed line intensities and the physical condition of this compact nebulosity. Based on the semiempirical ionization correction approach and model indications, we derived the elemental abundances; He, C, N, O, Ne, and Ar appear to be normal or marginally depleted compared to the average planetary nebula, while the remaining elements S, Cl, and K appear to be enhanced. IC 5117 is perhaps a very young compact planetary nebula, slightly more evolved than the other well-known compact planetary nebula IC 4997. The central stellar temperature is likely to be around 120,000 K, evolved from a C-rich asymptotic giant branch progenitor. C1 Korea Astron Observ, Taejon 305348, South Korea. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Chungnam Natl Univ, Dept Astron & Space Sci, Taejon 305764, South Korea. RP Hyung, S (reprint author), Korea Astron Observ, 61-1 Whaam Dong, Taejon 305348, South Korea. NR 34 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 889 EP 902 DI 10.1086/323962 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900037 ER PT J AU Miller, JM Wijnands, R Homan, J Belloni, T Pooley, D Corbel, S Kouveliotou, C van der Klis, M Lewin, WHG AF Miller, JM Wijnands, R Homan, J Belloni, T Pooley, D Corbel, S Kouveliotou, C van der Klis, M Lewin, WHG TI High-frequency quasi-periodic oscillations in the 2000 outburst of the Galactic microquasar XTE J1550-564 SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; relativity; stars : individual (XTE J1550-564); stars : oscillations; X-rays : stars ID X-RAY BINARIES; RXTE OBSERVATIONS; GRO J1655-40; MODEL AB We present an analysis of the high-frequency timing properties of the 2000 April-May outburst of the black hole candidate and Galactic microquasar XTE J1550-564, measured with the Rossi X-Ray Timing Explorer. The rapid X-ray variability we measure is consistent with the source being in either the "very high" or "intermediate" black hole state. Strong (5%-8% rms) quasi-periodic oscillations (QPOs) are found between 249 and 276 Hz; this represents the first detection of the same high-frequency QPO in subsequent outbursts of a transient black hole candidate. We also present evidence for lower frequency QPOs at approximately 188 Hz (3.5 sigma, single trial), also reported previously and likely present simultaneously with the higher frequency QPOs. We discuss these findings within the context of the 1998 outburst of XTE J1550-564 and comment on implications for models of QPOs, accretion flows, and black hole spin. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Osserv Astron Brera, I-20121 Milan, Italy. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Paris 07, F-91191 Gif Sur Yvette, France. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Miller, JM (reprint author), MIT, Ctr Space Res, Cambridge, MA 02139 USA. NR 29 TC 78 Z9 78 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 928 EP 933 DI 10.1086/324027 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900040 ER PT J AU Harris, MJ Teegarden, BJ Weidenspointner, G Palmer, DM Cline, TL Gehrels, N Ramaty, R AF Harris, MJ Teegarden, BJ Weidenspointner, G Palmer, DM Cline, TL Gehrels, N Ramaty, R TI Transient Gamma-Ray Spectrometer observations of gamma-ray lines from novae. III. The 478 keV line from Be-7 decay SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : observations; novae, cataclysmic variables; white dwarfs ID CLASSICAL NOVAE; REACTION-RATES; EMISSION; OUTBURST; SIMULATIONS; EXPLOSIONS; SPECTRA; SEARCH; LIMITS; MODELS AB The Wind spacecraft, which carries the Transient Gamma Ray Spectrometer (TGRS), moves in an extremely elliptical orbit that largely avoids Earth's trapped radiation belts and albedo gamma -radiation. The TGRS therefore enjoys a relatively low level of background, which is also extremely stable. We show how this stability enables modeling of the time variability of background lines, which in turn enables a novel technique of background subtraction for use in the detection of transient astrophysical lines. We apply a simple version of this method to the line at 478 keV that is expected to arise from nucleosynthesis of Be-7 in nearby novae. This search covers the entire southern ecliptic hemisphere during 1995-1997, including five known individual events and possible undiscovered individual events. The TGRS design also uses Wind's 3 s rotation period to modulate signals from the Galactic center. We use this feature of the instrument to search for a quasi-constant level of 478 keV emission from the accumulation of 7Be from several novae that are expected to occur in the direction of the Galactic center during that isotope's 53 day half-life. We derive upper limits on the transient (single nova) emission that improve on previous limits by about an order of magnitude and limits on the steady (many nova) emission that represent a factor of 2 improvement. Only weak limits can be placed on the key parameters in the nucleosynthesis and ejection of Be-7, however. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Harris, MJ (reprint author), Univ Space Res Assoc, Columbia, MD 21044 USA. RI Gehrels, Neil/D-2971-2012 NR 49 TC 14 Z9 14 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP 950 EP 957 DI 10.1086/323951 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JE UT WOS:000172852900043 ER PT J AU Kellogg, E Pedelty, JA Lyon, RG AF Kellogg, E Pedelty, JA Lyon, RG TI The X-ray system R Aquarii: A two-sided jet and central source SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : symbiotic; circumstellar matter; radio continuum : stars; stars : individual (R Aquarii); stars : winds, outflows; white dwarfs; X-rays : general ID RESOLUTION; SPECTRUM; PLASMA AB We report Chandra ACIS-S3 X-ray imaging and spectroscopy of the R Aquarii binary system that show a spatially resolved two-sided jet and an unresolved central source. This is the first published report of such an X-ray jet seen in an evolved similar to2-3 M-circle dot stellar system. At E < 1 keV, the X-ray jet extends to both the northeast (NE) and southwest (SW) relative to the central binary system. At 1 < E < 7.1 keV, R Aqr is a pointlike source centered on the star system. While both 3.5 cm radio continuum emission and X-ray emission appear coincident in projection and have maximum intensities at 7 " .5 NE of the central binary system, the next strongest X-ray component is located similar to 30 " SW of the central binary system and has no radio continuum counterpart. The X-ray jets are likely shock-heated in the recent past and are not in thermal equilibrium. The strongest SW X-ray jet component may have been shocked recently since there is no relic radio emission as expected from an older shock. At the position of the central binary, we detect X-ray emission below 1.6 keV consistent with blackbody emission at T similar to 2 x 10(6) K. There is also a prominent 6.4 keV feature, a possible fluorescence or collisionally excited Fe K line from an accretion disk or from the wind of the giant star. For this excitation to occur, there must be an unseen hard source of X-rays or particles in the immediate vicinity of the hot star. Such a source would be hidden from view by the surrounding edge-on accretion disk. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Instrument Technol Ctr, Greenbelt, MD 20771 USA. RP Kellogg, E (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St,MS 27, Cambridge, MA 02138 USA. RI Lyon, Richard/D-5022-2012 NR 19 TC 41 Z9 41 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP L151 EP L155 DI 10.1086/338594 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JF UT WOS:000172853000014 ER PT J AU McIntosh, SW Charbonneau, P AF McIntosh, SW Charbonneau, P TI Geometric effects in avalanche models of solar flares: Implications for coronal heating SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : flares; Sun : magnetic fields; Sun : UV radiation; Sun : X-rays, gamma rays ID QUIET-SUN; NANOFLARES; DIAGNOSTICS; REGIONS AB Observational inferences of the power-law frequency distribution of energy release by solar flares, and in particular its logarithmic slope alpha (E), depend critically on the geometric relationship assumed to relate the observed emitting area A and the underlying emitting volume V. Recent results on the fractal nature of avalanches in selforganized critical models for solar flares indicate that this relationship is a power law V proportional to A(gamma) with index gamma = 1.41(+/-0.04). We show that when proper account is made for the fractal geometry of the flaring volume, hitherto discrepant observational inferences of alpha (E) are brought in much closer agreement. The resulting values of alpha (E) lie tantalizingly close, but still below the critical value alpha (E) = 2.0, beyond which Parker's conjecture of coronal heating by nanoflares is tenable. C1 NASA, Goddard Space Flight Ctr, Dept Space Sci, European Space Agcy, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. RP McIntosh, SW (reprint author), NASA, Goddard Space Flight Ctr, Dept Space Sci, European Space Agcy, Mailcode 682-3, Greenbelt, MD 20771 USA. NR 17 TC 19 Z9 19 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP L165 EP L168 DI 10.1086/338739 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JF UT WOS:000172853000017 ER PT J AU Reames, DV Ng, CK AF Reames, DV Ng, CK TI On the phase of the 27 day modulation of anomalous and galactic cosmic rays at 1 AU during solar minimum SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; interplanetary medium; solar wind; Sun : magnetic fields ID ENERGETIC PARTICLES; MAGNETIC-FIELD; TRANSPORT; ACCELERATION; HELIOSPHERE; COMPONENTS; DEPENDENCE; DRIFT; SUN AB We report on the 27 day oscillations in the intensities of He and O ions of the anomalous cosmic rays (ACRs) observed near Earth by the Wind spacecraft during the 1995-1997 solar minimum period. Oscillations persist throughout the period with amplitudes as large as 50%. Galactic cosmic ray (GCR) oscillations, observed by neutron monitors, are in phase with the ACRs, but with much smaller amplitude (2%-3%). For a sustained period of almost a year, peak intensities occur near north-to-south crossings of the heliospheric current sheet and valleys near south-to-north crossings. In GCR observations in the 1974-1976 solar minimum, 27 day oscillations with a similar phase are seen. Understanding these observations poses a severe challenge for models of solar modulation as well as for models of the solar and heliospheric magnetic fields. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Reames, DV (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 18 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP L179 EP L182 DI 10.1086/338654 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JF UT WOS:000172853000020 ER PT J AU Vrtilek, SD Raymond, JC Boroson, B Kallman, T Quaintrell, H McCray, R AF Vrtilek, SD Raymond, JC Boroson, B Kallman, T Quaintrell, H McCray, R TI Simultaneous Chandra and Hubble Space Telescope observations of SMC X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; pulsars : individual (SMC X-1) ultraviolet : stars; X-rays : stars ID IMAGING SPECTROGRAPH; WIND DYNAMICS; RAY; VARIABILITY; SMC-X-1 AB We present first results from simultaneous ultraviolet (Hubble Space Telescope/STIS) and X-ray (Chandra/ACIS) observations of the SMC X-1/SK 160 eclipsing binary system. Observations covering four orbital phases during each of the X-ray high and X-ray low states were taken in 2000 October-November and 2001 April. The ultraviolet P Cygni lines show strong broad absorption near X-ray eclipse and narrow absorption when the X-ray source is in the line of sight. The effect is visible during both the X-ray high and X-ray low states; the UV continuum flux remains roughly constant in spite of more than an order-of-magnitude reduction in X-ray flux, as expected if the X-ray flux reduction is due to occultation of the X-ray source by a precessing disk rather than an intrinsic change in X-ray luminosity. The X-ray spectra are dominated by continuum emission in the X-ray high state. Occultation of the neutron star by the disk during the low state also implies that X-ray emission from the disk surface should be present, and the low-state spectra do show strong emission lines. During eclipse and during the X-ray low state, the continuum emission largely disappears, and we see line emission from O, Ne, Mg, and Fe and possibly from Si and S. The emission lines are consistent with recombination lines from mostly hydrogenic and helium-like species, which could be produced by photoionization in an extended stellar wind. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Open Univ, Milton Keynes MK7 6AA, Bucks, England. Univ Colorado, JILA, Boulder, CO 80309 USA. RP Vrtilek, SD (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 16 TC 19 Z9 19 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2001 VL 563 IS 2 BP L139 EP L142 DI 10.1086/338733 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JF UT WOS:000172853000011 ER PT J AU Bloss, WJ Nickolaisen, SL Salawitch, RJ Friedl, RR Sander, SP AF Bloss, WJ Nickolaisen, SL Salawitch, RJ Friedl, RR Sander, SP TI Kinetics of the ClO self-reaction and 210 nm absorption cross section of the ClO dimer SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ARCTIC POLAR VORTEX; OZONE LOSS RATES; ULTRAVIOLET-SPECTRUM; ANTARCTIC OZONE; TEMPERATURE-DEPENDENCE; VIBRATIONAL-SPECTRA; CHLORINE PEROXIDE; RATE CONSTANTS; 3 ISOMERS; WINTER AB The kinetics of the dimerization of CIO radicals, CIO + CIO + M --> Cl2O2 + M (1a), and the 210 nm absorption cross sections of the CIO dimer have been studied using the technique of flash photolysis with UV absorption spectroscopy. over the temperature range 183-245 K and pressure range 25-700 Torr. CIO radicals were generated following the photolysis of Cl-2/Cl2O/N-2 mixtures and were quantified,ia their differential absorption between the peak of the (12.0) band of the ((A) over tilde <-- (X) over tilde) transition at 275.2 nm and the adjacent minimum to higher wavelengths, while Cl2O2 formation was simultaneously monitored at 210 rim. CIO differential absorption cross sections were measured under identical conditions to the kinetic experiments by four separate calibration schemes. The rate coefficient measured at the lower temperatures studied (T < 200 K) was found to be up to 40% faster than extrapolation Of previous results would suggest, with the limiting low- and high-pressure rate coefficients for reaction I in nitrogen determined to be k(0) = (1.59 +/- 0.60) x 10(-32) x (T/300)(-4.50 +/-0.98) molecules(-2) cm(6) s(-1) and k(infinity) = (1.36 +/- 0.22) x 10(-12) x (T/300)(-3.09 +/-0.40) molecules(-1) cm(3) s(-1) respectively, obtained with F-c = 0.6. The corresponding value for k(0) in air is k((Matm)) = (1.49 +/- 0.56) x 10(-32) x (T/300)(-4.50 +/-0.98) molecules(-2) cm(6) s(-1). The 210 nm absorption cross section of Cl2O2 was measured following time-resolved monitoring of its formation via CIO radical association, and it mean value of (2.94 +/- 0.86) x 10(-18) molecule(-1) cm(2) obtained, temperature independent (to within +/- 15%) between 183 and 245 K. Errors are combined systematic uncertainties and 2 standard deviations statistical variation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sander, SP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Salawitch, Ross/B-4605-2009; Bloss, William/N-1305-2014 OI Salawitch, Ross/0000-0001-8597-5832; Bloss, William/0000-0002-3017-4461 NR 53 TC 45 Z9 45 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD DEC 20 PY 2001 VL 105 IS 50 BP 11226 EP 11239 DI 10.1021/jp012429y PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 505ZN UT WOS:000172945600011 ER PT J AU Cooper, G Kimmich, N Belisle, W Sarinana, J Brabham, K Garrel, L AF Cooper, G Kimmich, N Belisle, W Sarinana, J Brabham, K Garrel, L TI Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth SO NATURE LA English DT Article ID MURCHISON METEORITE; MASS SPECTROMETRY; CARBOXYLIC-ACIDS; AMINO-ACIDS; CHROMATOGRAPHY; DERIVATIVES; EVOLUTION; COMETS AB The much-studied Murchison meteorite is generally used as the standard reference for organic compounds in extraterrestrial material. Amino acids and other organic compounds(1) important in contemporary biochemistry are thought to have been delivered to the early Earth by asteroids and comets, where they may have played a role in the origin of life(2-4). Polyhydroxylated compounds (polyols) such as sugars, sugar alcohols and sugar acids are vital to all known lifeforms-they are components of nucleic acids (RNA, DNA), cell membranes and also act as energy sources. But there has hitherto been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically important organic compounds on Earth. Here we report that a variety of polyols are present in, and indigenous to, the Murchison and Murray meteorites in amounts comparable to amino acids. Analyses of water extracts indicate that extraterrestrial processes including photolysis and formaldehyde chemistry could account for the observed compounds. We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the first forms of life. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ G DAnnunzio, IRSPS, I-65127 Pescara, Italy. RP Cooper, G (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM gcooper@mail.arc.nasa.gov NR 29 TC 201 Z9 206 U1 6 U2 50 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD DEC 20 PY 2001 VL 414 IS 6866 BP 879 EP 883 DI 10.1038/414879a PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 503RB UT WOS:000172813300037 PM 11780054 ER PT J AU Hansen, JE Sato, M AF Hansen, JE Sato, M TI Trends of measured climate forcing agents SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE climate change; greenhouse gases; aerosols; air pollution ID ATMOSPHERIC METHANE; AIR-POLLUTION; BURDEN; VARIABILITY; CARBON; GROWTH AB The growth rate of climate forcing by measured greenhouse gases peaked near 1980 at almost 5 W/m(2) per century. This growth rate has since declined to approximate to3 W/m(2) per century, largely because of cooperative international actions. We argue that trends can be reduced to the level needed for the moderate "alternative" climate scenario (approximate to2 W/m(2) per century for the next 50 years) by means of concerted actions that have other benefits, but the forcing reductions are not automatic "co-benefits" of actions that slow CO2 emissions. Current trends of climate forcings by aerosols remain very uncertain. Nevertheless, practical constraints on changes in emission levels suggest that global warming at a rate +0.15 +/- 0.05 degreesC per decade will occur over the next several decades. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Earth Inst, Ctr Climate Syst Res, New York, NY 10025 USA. RP Hansen, JE (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 43 TC 124 Z9 133 U1 3 U2 32 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 18 PY 2001 VL 98 IS 26 BP 14778 EP 14783 DI 10.1073/pnas.261553698 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 504GK UT WOS:000172848800011 PM 11752424 ER PT J AU Myneni, RB Dong, J Tucker, CJ Kaufmann, RK Kauppi, PE Liski, J Zhou, L Alexeyev, V Hughes, MK AF Myneni, RB Dong, J Tucker, CJ Kaufmann, RK Kauppi, PE Liski, J Zhou, L Alexeyev, V Hughes, MK TI A large carbon sink in the woody biomass of Northern forests SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ATMOSPHERIC CO2; LAND; FLUXES; BUDGET; CYCLE AB The terrestrial carbon sink, as of yet unidentified, represents 15-30% of annual global emissions of carbon from fossil fuels and industrial activities. Some of the missing carbon is sequestered in vegetation biomass and, under the Kyoto Protocol of the United Nations Framework Convention on Climate Change, industrialized nations can use certain forest biomass sinks to meet their greenhouse gas emissions reduction commitments. Therefore, we analyzed 19 years of data from remote-sensing spacecraft and forest inventories to identify the size and location of such sinks. The results, which cover the years 1981-1999, reveal a picture of biomass carbon gains in Eurasian boreal and North American temperate forests and losses in some Canadian boreal forests. For the 1.42 billion hectares of Northern forests, roughly above the 30th parallel, we estimate the biomass sink to be 0.68 +/- 0.34 billion tons carbon per year, of which nearly 70% is in Eurasia, in proportion to its forest area and in disproportion to its biomass carbon pool. The relatively high spatial resolution of these estimates permits direct validation with ground data and contributes to a monitoring program of forest biomass sinks under the Kyoto protocol. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Helsinki, Dept Limnol & Environm Protect, FIN-00014 Helsinki, Finland. Univ Helsinki, Dept Forest & Ecol, FIN-00014 Helsinki, Finland. Int Inst Appl Syst Anal, Forest Sect, A-2361 Laxenburg, Austria. European Forest Inst, FIN-80100 Joensuu, Finland. St Petersburg Forest Ecol Ctr, St Petersburg 194021, Russia. Univ Arizona, Tree Ring Res Lab, Tucson, AZ 85721 USA. RP Myneni, RB (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. RI Zhou, Liming/A-2688-2012; Hughes, Malcolm/F-3350-2014; Myneni, Ranga/F-5129-2012; Liski, Jari/O-8494-2016 OI Hughes, Malcolm/0000-0003-1062-3167; Liski, Jari/0000-0002-0847-8207 NR 30 TC 334 Z9 379 U1 14 U2 119 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 18 PY 2001 VL 98 IS 26 BP 14784 EP 14789 DI 10.1073/pnas.261555198 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 504GK UT WOS:000172848800012 PM 11742094 ER PT J AU Miao, XS Balazs, GH Murakawa, SKK Li, QX AF Miao, XS Balazs, GH Murakawa, SKK Li, QX TI Congener-specific profile and toxicity assessment of PCBs in green turtles (Chelonia mydas) from the Hawaiian Islands SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE polychlorinated biphenyls; PCBs; green turtle; marine pollution ID CHIRAL POLYCHLORINATED-BIPHENYLS; DIBENZO-P-DIOXINS; ENVIRONMENTAL CONTAMINATION; ENANTIOMERIC RATIOS; MEDITERRANEAN-SEA; SNAPPING TURTLES; SULFURIC-ACID; TISSUES; SERPENTINA; COPLANAR AB Chemical pollution may play a role in the etiology of fibropapillomatosis in green turtles (Chelonia mydas). In this preliminary study, polychlorinated biphenyls (PCBs) were measured in the livers and adipose fats of green turtles collected after they were stranded on Oahu Island, Hawaii in 1992-1993. Average concentrations of total PCBs were 45-58 ng/g dry weight and 73-665 ng/g in the liver and adipose tissues, respectively. Hexachlorobiphenyls were predominant homologues, PCBs 153 and 138 were dominant congeners in all the turtle tissues. Among the most toxic coplanar congeners, in the order of abundance, were PCB 77 > 126 > 169. Estimated toxic equivalents (TEQs) of PCBs to 2,3,7,8-tetrachlorodibenzo-p-dioxin were 8-15 pg/g in the livers and 13-48 pg/g in the adipose tissues. PCB 126 contributed 85-91%, of the total TEQs. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Hawaii, Dept Mol Biosci & Biosyst Engn, Honolulu, HI 96822 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. RP Li, QX (reprint author), Univ Hawaii, Dept Mol Biosci & Biosyst Engn, Honolulu, HI 96822 USA. NR 26 TC 24 Z9 25 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD DEC 17 PY 2001 VL 281 IS 1-3 BP 247 EP 253 DI 10.1016/S0048-9697(01)00835-X PG 7 WC Environmental Sciences SC Environmental Sciences & Ecology GA 506JU UT WOS:000172967400021 PM 11778957 ER PT J AU Smialek, JL AF Smialek, JL TI Oxidative recession, sulfur release, and Al(2)O(3) spallation for Y-doped alloys SO SCRIPTA MATERIALIA LA English DT Article DE oxidation; sulfur; segregation; alumina scales ID SUPERALLOYS; ADHERENCE; ADHESION; SCALE; SEGREGATION; ALPHA-AL2O3; INTERFACES; RESISTANCE; REMOVAL; ALUMINA AB Some spallation of alumina scales occurred after long-term oxidation of Rene'N5 + Y and immersion in water. It is proposed that 0.15 monolayers of sulfur segregation is enabled as the surface is consumed by oxidation for every 1 mg/cm(2) weight gain and a bulk sulfur content of 5 ppmw S. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Smialek, JL (reprint author), NASA, Glenn Res Ctr, MS 106-1,2100 Brookpk Rd, Cleveland, OH 44135 USA. EM james.I.smialek@grs.nasa.gov NR 17 TC 10 Z9 10 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD DEC 17 PY 2001 VL 45 IS 12 BP 1327 EP 1333 DI 10.1016/S1359-6462(01)01127-7 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 516LV UT WOS:000173555500001 ER PT J AU Stothers, RB AF Stothers, RB TI A chronology of annual mean effective radii of stratospheric aerosols from volcanic eruptions during the twentieth century as derived from ground-based spectral extinction measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OPTICAL DEPTH PERTURBATIONS; MT-PINATUBO ERUPTION; EL-CHICHON CLOUD; ATMOSPHERIC EXTINCTION; SIZE DISTRIBUTION; MOUNT-PINATUBO; LA-SILLA; PARTICLE SIZES; II SATELLITE; MAUNA-LOA AB Stratospheric extinction can be derived from ground-based spectral photometric observations of the Sun and other stars (as well as from satellite and aircraft measurements available since 1979) and is found to increase after large volcanic eruptions. This increased extinction shows a characteristic wavelength dependence that gives information about the chemical composition and the effective (or area-weighted mean) radius of the particles responsible for it. Known to be tiny aerosols constituted of sulfuric acid in a water solution, the stratospheric particles at midlatitudes exhibit a remarkable uniformity of their column-averaged effective radii r(eff) in the first few months after the eruption. Considering the seven largest aerosol-producing eruptions of the twentieth century, r(eff) at this phase of peak aerosol abundance is similar to0.3 mum in all cases. A year later, r(eff) either has remained about the same size (almost certainly in the case of the Katmai eruption of 1912) or has increased to similar to0.5 mum (definitely so for the Pinatubo eruption of 1991). The reasons for this divergence in aerosol growth are unknown. C1 NASA, Goddard Inst Space Studies, Inst Space Studies, New York, NY 10025 USA. RP Stothers, RB (reprint author), NASA, Goddard Inst Space Studies, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM rstothers@giss.nasa.gov NR 66 TC 11 Z9 11 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32043 EP 32049 DI 10.1029/2001JD000414 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100031 ER PT J AU Read, WG Waters, JW Wu, DL Stone, EM Shippony, Z Smedley, AC Smallcomb, CC Oltmans, S Kley, D Smit, HGJ Mergenthaler, JL Karki, MK AF Read, WG Waters, JW Wu, DL Stone, EM Shippony, Z Smedley, AC Smallcomb, CC Oltmans, S Kley, D Smit, HGJ Mergenthaler, JL Karki, MK TI UARS microwave limb sounder upper tropospheric humidity measurement: Method and validation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COLLISION-INDUCED ABSORPTION; WATER-VAPOR ABSORPTION; ATMOSPHERE RESEARCH SATELLITE; STRATOSPHERIC AEROSOL; RELATIVE-HUMIDITY; 2.3 CM-1; EL-NINO; TEMPERATURES; MLS; CLIMATOLOGY AB The methodology and validation of upper tropospheric humidity (UTH) measurements by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) are described. The MLS instrument was not specifically designed to measure UTH, but its measurement is achieved by modeling the radiance signal from a window channel as the instrument field of view is scanned through the troposphere. UTH is retrieved as a piecewise-linear function in relative humidity with respect to ice (% RHi) with breakpoints at 147, 215, 316, and 464 hPa. MLS version 4.9 is believed to be the most accurate version to date; its estimated global-averaged accuracy(precision) is 23(21), 22(10), 22(8), and 50(19) %RHi at 147, 215, 316, and 464, hPa respectively. The validation of UTH is established by its consistency with (1) climatological fields, (2) coincident comparisons with in situ Vaisala RS80 balloon sondes, frostpoint hygrometers and Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft measurements, (3) cirrus observations, and (4) meteorological dynamics and assimilation fields. MLS climatological UTH is morphologically consistent with Stratospheric Aerosol and Gas Experiment 11 and Vaisala zonal climatologies. Comparisons with coincident in situ data show a wide range of agreement. Relative to the other in situ instruments, V4.9 MLS humidities agree on average within 11 % at 147 hPa, 3-36% dry at 215 hPa, and 14-39% dry at 316 and 464 hPa. The standard deviation of the individual comparisons about the mean between MLS UTH and the other techniques is approximately 25 %RHi at all heights. Humidity measurements in cirrus are compared with UARS Cryogenic Limb Array Etalon Spectrometer (CLAES) extinction measurements and an MLS cirrus detection algorithm. CLAES extinction measurements from 316 to 147 hPa which indicate the presence of cirrus correspond well with MLS UTH measurements greater than similar to100 %RHi. Global MLS UTH distributions appear consistent with those expected from upper tropospheric dynamics and with the Goddard Data Assimilation Office humidity fields. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Res Ctr Juelisch GmbH, Dept Chem & Dynam Geosphere, Inst Chem Polluted Atmosphere, D-52425 Julich, Germany. Lockheed Martin Res Adv Technol Ctr, Palo Alto, CA 94304 USA. NASA Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Read, WG (reprint author), CALTECH, Jet Propuls Lab, Mail Stop 183-701 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bill@mls.jpl.nasa.gov; joe@mls.jpl.nasa.gov; dwu@mls.jpl.nasa.gov; emstone@snet.net; zvi@mls.jpl.nasa.gov; andrea@mls.jpl.nasa.gov; smallcomb1@home.com; soltmans@cmdl.noaa.gov; D.Kley@fz-juelich.de; h.smit@fz-juelich.de; MERGEN@claes.spasci.com; karki@dao.gsfc.nasa.gov RI Smit, Herman/J-2397-2012; Wu, Dong/D-5375-2012 OI Smit, Herman/0000-0002-2268-4189; NR 72 TC 60 Z9 60 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32207 EP 32258 DI 10.1029/2000JD000122 PG 52 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100042 ER PT J AU Andrews, AE Boering, KA Daube, BC Wofsy, SC Loewenstein, M Jost, H Podolske, JR Webster, CR Herman, RL Scott, DC Flesch, GJ Moyer, EJ Elkins, JW Dutton, GS Hurst, DF Moore, FL Ray, EA Romashkin, PA Strahan, SE AF Andrews, AE Boering, KA Daube, BC Wofsy, SC Loewenstein, M Jost, H Podolske, JR Webster, CR Herman, RL Scott, DC Flesch, GJ Moyer, EJ Elkins, JW Dutton, GS Hurst, DF Moore, FL Ray, EA Romashkin, PA Strahan, SE TI Mean ages of stratospheric air derived from in situ observations of CO2, CH4, and N2O SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDLATITUDE LOWER STRATOSPHERE; ABSORPTION SPECTROMETER ALIAS; CARBON-DIOXIDE; 2-DIMENSIONAL MODEL; UPPER TROPOSPHERE; MIDDLE LATITUDES; PIPE MODEL; TRANSPORT; TRACERS; VORTEX AB Accurate mean ages for stratospheric air have been derived from a spatially and temporally comprehensive set of in situ observations Of CO2, CH4, and N2O obtained from 1992 to 1998 from the NASA ER-2 aircraft and balloon flights. Errors associated with the tropospheric CO2 seasonal cycle and interannual variations in the CO2 growth rate are < 0.5 year throughout the stratosphere and < 0.3 year for air older than 2 years (N2O < 275 ppbv), indicating that the age spectra are broad enough to attenuate these influences over the time period covered by these observations. The distribution of mean age with latitude and altitude provides detailed, quantitative information about the general circulation of the stratosphere. At 20 km, sharp meridional gradients in the mean age are observed across the subtropics. Between 20 and 30 km, the average difference in mean age between the tropics and midlatitudes is similar to2 years, with slightly smaller differences at higher and lower altitudes. The mean age in the midlatitude middle stratosphere (similar to25-32 km) is relatively constant with respect to altitude at 5 +/- 0.5 years. Comparison with earlier balloon observations Of CO2 dating back to the 1970s indicates that the mean age of air in this region has remained within 1 year of its current value over the last 25 years. A climatology of mean age is derived from the observed compact relationship between mean age and N2O. These characteristics of the distribution of mean age in the stratosphere will serve as critically needed diagnostics for models of stratospheric transport. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. NASA Ames Res Ctr, Moffett Field, CA USA. Bay Area Environm Res Inst, San Francisco, CA USA. CALTECH, NASA Jet Propuls Lab, Pasadena, CA USA. NOAA Climate Monitoring & Diagnost Lab, Boulder, CO USA. Gen Sci Corp, Beltsville, MD USA. RP Andrews, AE (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 20 Oxford St, Cambridge, MA 02138 USA. EM andrews@code916.gsfc.nasa.gov RI Strahan, Susan/H-1965-2012; Herman, Robert/H-9389-2012; Andrews, Arlyn/K-3427-2012; Ray, Eric/D-5941-2013; Hurst, Dale/D-1554-2016 OI Herman, Robert/0000-0001-7063-6424; Ray, Eric/0000-0001-8727-9849; Hurst, Dale/0000-0002-6315-2322 NR 57 TC 105 Z9 106 U1 3 U2 20 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32295 EP 32314 DI 10.1029/2001JD000465 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100046 ER PT J AU Newchurch, MJ Liu, X Kim, JH Bhartia, PK AF Newchurch, MJ Liu, X Kim, JH Bhartia, PK TI On the accuracy of Total Ozone Mapping Spectrometer retrievals over tropical cloudy regions SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC COLUMN OZONE; STRATOSPHERIC OZONE; TOMS MEASUREMENTS AB Motivated by the desire to accurately derive tropospheric ozone from Total Ozone Mapping Spectrometer (TOMS) measurements, we investigate several aspects of these observations in the presence of highly reflecting clouds. Using the collocated Temperature Humidity InfraRed (THIR) measurements of cloud-top pressures, we identify three TOMS algorithm errors resulting from the inaccurate assignment of cloud-top pressure. The most significant error results from the inappropriate tropospheric ozone amount added below cloudy scenes to complete the total ozone column. After accounting for the cloud-height errors, we find significant total ozone column excesses of 10-15 Dobson units (DU) (1 DU 2.6867 x 10(16) molecules cm(-2)) over high-altitude, highly reflecting clouds compared with clear area observations. After accounting for additional algorithm errors involving the tropospheric ozone climatology and considering potential dynamical, photochemical, and NIMBUS-7/Earth Probe calibration errors, approximately 4-9 DU excesses over cloudy scenes remain. We speculate that the TOMS algorithm approximation of clouds as opaque Lambertian reflecting surfaces may account for a significant portion of these unexplained excesses. The excess ozone due to calibration error and unknown sources will affect the tropospheric ozone derived from TOMS measurements using clear/cloudy difference techniques. C1 Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. Pusan Natl Univ, Dept Atmospher Sci, Pusan 609735, South Korea. NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Ctr Atomospher Res, Atmospher Chem Div, Boulder, CO USA. RP Newchurch, MJ (reprint author), Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. EM mike@nsstc.uah.edu; xliu@nsstc.uah.edu; jaekim@sabunim.com; bhartia@chapman.gsfc.nasa.gov RI Liu, Xiong/P-7186-2014; Bhartia, Pawan/A-4209-2016 OI Liu, Xiong/0000-0003-2939-574X; Bhartia, Pawan/0000-0001-8307-9137 NR 24 TC 29 Z9 29 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32315 EP 32326 DI 10.1029/2000JD000151 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100047 ER PT J AU Raper, JL Kleb, MM Jacob, DJ Davis, DD Newell, RE Fuelberg, HE Bendura, RJ Hoell, JM McNeal, RJ AF Raper, JL Kleb, MM Jacob, DJ Davis, DD Newell, RE Fuelberg, HE Bendura, RJ Hoell, JM McNeal, RJ TI Pacific Exploratory Mission in the tropical Pacific: PEM-Tropics B, March-April 1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WESTERN NORTH PACIFIC; EXPERIMENT ACE 1; OZONE PHOTOCHEMISTRY; OH MEASUREMENTS; BOUNDARY-LAYER; SOUTH-PACIFIC; TROPOSPHERE; CHEMISTRY; TRANSPORT AB The Pacific Exploratory Mission - Tropics B (PEM-Tropics 13) was conducted by the NASA Global Tropospheric Experiment (GTE) over the tropical Pacific Ocean in March-April 1999. It used the NASA DC-8 and P-3B aircraft equipped with extensive instrumentation for measuring numerous chemical compounds and gases. Its central objective was to improve knowledge of the factors controlling ozone, OH, aerosols, and related species over the tropical Pacific. Geographical coverage ranged from 38degreesN to 36degreesS and 148degreesW to 76degreesE. Major deployment sites included Hilo, Hawaii, Christmas Island, Tahiti, Fiji, and Easter Island. PEM-Tropics B was a sequel to PEM-Tropics A, which was conducted in September-October 1996 and encountered considerable biomass burning. PEM-Tropics B, conducted in the wet season of the southern tropics, observed an exceedingly clean atmosphere over the South Pacific but a variety of pollution influences over the tropical North Pacific. Photochemical ozone loss over both the North and the South Pacific exceeded local photochemical production by about a factor of 2, implying a major deficit in the tropospheric ozone budget. Dedicated flights investigated the sharp air mass transitions at the Intertropical Convergence Zone (ITCZ) and the South Pacific Convergence Zone (SPCZ). Extensive OH observations permitted the first large-scale comparisons with photochemical model predictions. High concentrations of oxygenated organics were observed ubiquitously in the tropical Pacific atmosphere and may have important implications for global HOx and NOx budgets. Extensive equatorial measurements of dimethyl sulfide and OH suggest that important aspects of marine sulfur chemistry are still poorly understood. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NASA Headquarters, Washington, DC 20546 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Raper, JL (reprint author), NASA, Langley Res Ctr, Mail Stop 483, Hampton, VA 23681 USA. EM j.l.raper@larc.nasa.gov; m.m.kleb@larc.nasa.gov; r.j.bendura@larc.nasa.gov NR 23 TC 61 Z9 61 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32401 EP 32425 DI 10.1029/2000JD900833 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100053 ER PT J AU Fuelberg, HE Newell, RE Westberg, DJ Maloney, JC Hannan, JR Martin, BD Avery, MA Zhu, Y AF Fuelberg, HE Newell, RE Westberg, DJ Maloney, JC Hannan, JR Martin, BD Avery, MA Zhu, Y TI A meteorological overview of the second Pacific Exploratory Mission in the Tropics SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEM-TROPICS; SOUTHERN OSCILLATION; TRAJECTORIES; TRANSPORT; PERIOD; TRACE; ENSO; AIR AB Meteorological conditions over the central Pacific Basin are summarized during NASA's second Pacific Exploratory Mission in the Tropics (PEM-B) which was conducted during February-April 1999. Mean flow patterns during PEM-B are described. Important features near the surface include subtropical anticyclones, the South Pacific Convergence Zone (SPCZ), and the Intertropical Convergence Zone (ITCZ). The ITCZ is found to exhibit a double structure, with branches at similar to5degreesN and similar to5degreesS. Both the ITCZ and SPCZ are areas of widespread cloudiness and convection. Extensive lightning occurs over the land masses surrounding the Pacific Basin and over the central South Pacific Ocean itself. PEM-B occurs during a La Nina period of relatively cold sea surface temperatures in the tropical Pacific. Compared to climatology, the PEM-B period exhibits deep convection located west of its typical position, stronger than normal easterly trade winds, a relatively strong (weak) northern (southern) hemispheric jet stream, the SPCZ located west of its normal position, and an upper tropospheric cyclonic wind couplet that straddles the equator. Circulation patterns during PEM-B are compared with those of PEM-A which occurred during August-September 1996. PEM-B is found to exhibit a less organized ITCZ, a comparatively weak jet stream in the Southern Hemisphere, a relatively strong jet stream in the Northern Hemisphere, and enhanced convection over the central Pacific. Finally, meteorological conditions for selected flights are discussed utilizing streamlines, 10-day backward trajectories, thermodynamic soundings, and satellite imagery. Air parcels sampled by the aircraft are found to originate or pass over diverse regions, including Asia, South America, southern Africa, and Australia. Some parcels remain over the Pacific Ocean during the preceding 10-day period. C1 Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Sci Applicat Int Corp, Hampton, VA 23669 USA. RP Fuelberg, HE (reprint author), Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. EM fuelberg@met.fsu.edu NR 28 TC 16 Z9 16 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32427 EP 32443 DI 10.1029/2001JD900173 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100054 ER PT J AU Cho, JYN Anderson, BE Barrick, JDW Thornhill, KL AF Cho, JYN Anderson, BE Barrick, JDW Thornhill, KL TI Aircraft observations of boundary layer turbulence: Intermittency and the cascade of energy and passive scalar variance SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FULLY-DEVELOPED TURBULENCE; VELOCITY STRUCTURE FUNCTIONS; EXTENDED SELF-SIMILARITY; LOWER STRATOSPHERE; UPPER TROPOSPHERE; 2-DIMENSIONAL TURBULENCE; INERTIAL RANGE; SHEAR FLOWS; TEMPERATURE; FLUCTUATIONS AB We analyze boundary layer velocity and temperature measurements acquired by aircraft at 22 Hz. The calculated longitudinal velocity third-order structure function yields approximate agreement with Kolmogorov's four-fifths law for the scale range similar to10-100 in with a downscale energy flux of similar to4 X 10(-5) m(2) s(-3). For scales greater than similar to10 km the sign is reversed, implying an inverse energy cascade with an estimated flux of similar to10(-5) m(2) s(-3) associated with two-dimensional stratified turbulence. The mixed structure function of longitudinal velocity and squared temperature increment follows Yaglom's four-thirds law in the same scale range, yielding an estimated downscale temperature variance flux of similar to5 x 10(-7) K-2 s(-1). Analysis of higher-order structure functions yields anomalous scaling for both velocity and temperature. The scaling also reveals second-order multifractal phase transitions for both velocity and temperature data. Above the transition moments, asymptotes varying with the number of realizations argue against the log-Poisson model. The log-Levy model is better able to explain the observed characteristics. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cho, JYN (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave,Room 54-1823, Cambridge, MA 02139 USA. EM jcho@pemtropics.mit.edu; b.e.anderson@larc.nasa.gov; j.d.barrick@larc.nasa.gov; k.l.thornhill@larc.nasa.gov NR 60 TC 5 Z9 5 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32469 EP 32479 DI 10.1029/2001JD900079 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100056 ER PT J AU Browell, EV Fenn, MA Butler, CF Grant, WB Ismail, S Ferrare, RA Kooi, SA Brackett, VG Clayton, MB Avery, MA Barrick, JDW Fuelberg, HE Maloney, JC Newell, RE Zhu, Y Mahoney, MJ Anderson, BE Blake, DR Brune, WH Heikes, BG Sachse, GW Singh, HB Talbot, RW AF Browell, EV Fenn, MA Butler, CF Grant, WB Ismail, S Ferrare, RA Kooi, SA Brackett, VG Clayton, MB Avery, MA Barrick, JDW Fuelberg, HE Maloney, JC Newell, RE Zhu, Y Mahoney, MJ Anderson, BE Blake, DR Brune, WH Heikes, BG Sachse, GW Singh, HB Talbot, RW TI Large-scale air mass characteristics observed over the remote tropical Pacific Ocean during March-April 1999: Results from PEM-Tropics B field experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AEROSOL OPTICAL-PROPERTIES; MARINE BOUNDARY-LAYER; SOUTH-PACIFIC; EXPLORATORY MISSION; TROPOSPHERIC OZONE; DIAL MEASUREMENTS; BURNING SEASON; WATER-VAPOR; DISTRIBUTIONS; SUMMERTIME AB Eighteen long-range flights over the Pacific Ocean between 38degreesS to 20degreesN and 166degreesE to 90degreesW were made by the NASA DC-8 aircraft during the NASA Pacific Exploratory Mission (PEM) Tropics B conducted from March 6 to April 18, 1999. Two lidar systems were flown on the DC-8 to remotely measure vertical profiles of ozone (O-3), water vapor (1420), aerosols, and clouds from near the surface to the upper troposphere along their Right track. In situ measurements of a wide range of gases and aerosols were made on the DC-8 for comprehensive characterization of the air and for correlation with the lidar remote measurements. The transition from northeasterly flow of Northern Hemispheric (NE) air on the northern side of the Intertropical Convergence Zone (ITCZ) to generally easterly flow of Southern Hemispheric (SH) air south of the ITCZ was accompanied by a significant decrease in O-3, carbon monoxide, hydrocarbons, and aerosols and an increase in H2O. Trajectory analyses indicate that air north of the ITCZ came from Asia and/or the United States, while the air south of the ITCZ had a long residence time over the Pacific, perhaps originating over South America several weeks earlier. Air south of the South Pacific Convergence Zone (SPCZ) came rapidly from the west originating over Australia or Africa. This air had enhanced O-3 and aerosols and an associated decrease in H2O. Average latitudinal and longitudinal distributions of O-3 and H2O were constructed from the remote and in situ O-3 And H2O data, and these distributions are compared with results from PEM-Tropics A conducted in August-October 1996. During PEM-Tropics B, low O-3 air was found in the SH across the entire Pacific Basin at low latitudes. This was in strong contrast to the photochemically enhanced O-3 levels found across the central and eastern Pacific low latitudes during PEM-Tropics A. Nine air mass types were identified for PEM-Tropics B based on their O-3, aerosols, clouds, and potential vorticity characteristics. The data from each flight were binned by altitude according to air mass type, and these results showed the relative observational frequency of the different air masses as a function of altitude in seven regions over the Pacific. The average chemical composition of the major air mass types was determined from in situ measurements in the NH and SH, and these results provided insight into the origin, lifetime, and chemistry of the air in these regions. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Ames Res Ctr, Moffett Field, CA 94305 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Browell, EV (reprint author), NASA, Langley Res Ctr, MS-401A, Hampton, VA 23681 USA. EM e.v.browell@larc.nasa.gov RI Grant, William/B-8311-2009 OI Grant, William/0000-0002-1439-3285 NR 37 TC 28 Z9 28 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32481 EP 32501 DI 10.1029/2001JD900001 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100057 ER PT J AU Oltmans, SJ Johnson, BJ Harris, JM Vomel, H Thompson, AM Koshy, K Simon, P Bendura, RJ Logan, JA Hasebe, F Shiotani, M Kirchhoff, VWJH Maata, M Sami, G Samad, A Tabuadravu, J Enriquez, H Agama, M Cornejo, J Paredes, F AF Oltmans, SJ Johnson, BJ Harris, JM Vomel, H Thompson, AM Koshy, K Simon, P Bendura, RJ Logan, JA Hasebe, F Shiotani, M Kirchhoff, VWJH Maata, M Sami, G Samad, A Tabuadravu, J Enriquez, H Agama, M Cornejo, J Paredes, F TI Ozone in the Pacific tropical troposphere from ozonesonde observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEM-TROPICS; TRANSPORT; FOREST; OCEAN; TRACE AB Ozone vertical profile measurements obtained from ozonesondes flown at Fiji, Samoa, Tahiti, and the Galapagos are used to characterize ozone in the troposphere over the tropical Pacific. There is a significant seasonal variation at each of these sites. At sites in both the eastern and western Pacific, ozone mixing ratios are greatest at almost all levels in the troposphere during the September-November season and smallest during March-May. The vertical profile has a relative maximum at all of the sites in the midtroposphere throughout the year (the largest amounts are usually found near the tropopause). This maximum is particularly pronounced during the September-November season. On average, throughout the troposphere, the Galapagos has larger ozone amounts than the western Pacific sites. A trajectory climatology is used to identify the major flow regimes that are associated with the characteristic ozone behavior at various altitudes and seasons. The enhanced ozone seen in the midtroposphere during September-November is associated with flow from the continents. In the western Pacific this flow is usually from southern Africa (although 10-day trajectories do not always reach the continent) but also may come from Australia and Indonesia, In the Galapagos the ozone peak in the midtroposphere is seen in flow from the South American continent and particularly from northern Brazil, High ozone concentrations within potential source regions and flow characteristics associated with the ozone mixing ratio peaks seen in both the western and eastern Pacific suggest that these enhanced ozone mixing ratios result from biomass burning. In the upper troposphere, low ozone amounts are seen with flow that originates in the convective western Pacific. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. INAMHI, Galapagos, Ecuador. NASA, Langley Res Ctr, Hampton, VA 23681 USA. INAMHI, Quito, Ecuador. Ibaraki Univ, Dept Environm Sci, Mito, Ibaraki 3100056, Japan. INPE, BR-12201970 Sao Jose Dos Campos, Brazil. Univ S Pacific, Sch Pure & Appl Biol, Suva, Fiji. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Hokkaido Univ, Grad Sch Environm Earth Sci, Sapporo, Hokkaido 060, Japan. Meteo France, Tahiti, Fr Polynesia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Oltmans, SJ (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. EM soltmans@cmdl.noaa.gov RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 21 TC 36 Z9 36 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32503 EP 32525 DI 10.1029/2000JD900834 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100058 ER PT J AU Thouret, V Cho, JYN Evans, MJ Newell, RE Avery, MA Barrick, JDW Sachse, GW Gregory, GL AF Thouret, V Cho, JYN Evans, MJ Newell, RE Avery, MA Barrick, JDW Sachse, GW Gregory, GL TI Tropospheric ozone layers observed during PEM-Tropics B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC EXPLORATORY MISSION; MOZAIC AIRBORNE PROGRAM; NASA DC-8; ATMOSPHERIC LAYERS; WEST; AIRCRAFT; EXCHANGE AB In this paper we analyze distinct layers seen in the tropospheric ozone and water vapor profiles taken during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission in the Tropical Pacific (PEM-Tropics) Phase B campaign. In summary, fewer layers were observed in this campaign than during the PEM-Tropics A campaign. However, of those layers found, there were relatively more ozone-rich-water-vapor-poor layers (68% versus 52%). The percentage of the sampled troposphere occupied by layers during PEM-Tropics B was less than half of that found during PEM-Tropics A (8% versus 20%). The differences between these two campaigns suggest a seasonal variation in the occurrence of layers. This is confirmed using measurements made by the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Langley Res Ctr, Hampton, VA USA. RP Thouret, V (reprint author), Univ Toulouse 3, Observ Midi Pyrenees, CNRS UMR 5560, Lab Aerol, 14 Ave Edouard Belin, F-31400 Toulouse, France. EM thov@aero.obs-mip.fr; jcho@pemtropics.mit.edu; mje@io.harvard.edu; renewell@mit.edu; m.a.avery@larc.nasa.gov; j.d.barrick@larc.nasa.gov; g.w.sachse@larc.nasa.gov; gregory@widomaker.com RI Evans, Mathew/A-3886-2012 OI Evans, Mathew/0000-0003-4775-032X NR 22 TC 13 Z9 13 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32527 EP 32538 DI 10.1029/2001JD900011 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100059 ER PT J AU Avery, MA Westberg, DJ Fuelberg, HE Newell, RE Anderson, BE Vay, SA Sachse, GW Blake, DR AF Avery, MA Westberg, DJ Fuelberg, HE Newell, RE Anderson, BE Vay, SA Sachse, GW Blake, DR TI Chemical transport across the ITCZ in the central Pacific during an El Nino-Southern Oscillation cold phase event in March-April 1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEM-TROPICS; EXPLORATORY MISSION; TROPOSPHERE AB We examine interhemispheric transport processes that occurred over the central Pacific during the PEM-Tropics B mission (PTB) in March-April 1999 by correlating the observed distribution of chemical tracers with the prevailing and anomalous windfields. The Intertropical Convergence Zone (ITCZ) had a double structure during PTB, and interhemispheric mixing occurred in the equatorial region between ITCZ branches. The anomalously strong tropical easterly surface wind had a large northerly component across the equator in the central Pacific, causing transport of aged, polluted air into the Southern Hemisphere (SH) at altitudes below 4 km. Elevated concentrations of chemical tracers from the Northern Hemisphere (NH) measured south of the equator in the central Pacific during PTB may represent an upper limit because the coincidence of seasonal and cold phase ENSO conditions are optimum for this transport. Stronger and more consistent surface convergence between the northeasterly and southeasterly trade winds in the Southern Hemisphere (SH) resulted in more total convective activity in the SH branch of the ITCZ, at about 6degreesS. The middle troposphere between 4-7 km was a complex shear zone between prevailing northeasterly winds at low altitudes and southwesterly winds at higher altitudes. Persistent anomalous streamline patterns and the chemical tracer distribution show that during PTB most transport in the central Pacific was from SH to NH across the equator in the upper troposphere. Seasonal differences in source strength caused larger interhemispheric gradients of chemical tracers during PTB than during the complementary PEM-Tropics A mission in September-October 1996. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Avery, MA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 14 TC 22 Z9 22 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32539 EP 32553 DI 10.1029/2001JD000728 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100060 ER PT J AU Staudt, AC Jacob, DJ Logan, JA Bachiochi, D Krishnamurti, TN Sachse, GW AF Staudt, AC Jacob, DJ Logan, JA Bachiochi, D Krishnamurti, TN Sachse, GW TI Continental sources, transoceanic transport, and interhemispheric exchange of carbon monoxide over the Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EXPLORATORY MISSION-WEST; LONG-RANGE TRANSPORT; TROPOSPHERIC OZONE; GENERAL-CIRCULATION; AIR-POLLUTION; INTERANNUAL VARIABILITY; GLOBAL SIMULATION; AMERICAN-SAMOA; NORTH-AMERICA; PEM-WEST AB The Pacific Exploratory Mission to the Tropics phase B (PEM-Tropics B) aircraft campaign in March-April 1999 surveyed the chemical composition of the Pacific atmosphere from 35degreesN to 35degreesS and up to 12 km altitude. We use these observations in combination with a global three-dimensional model driven by assimilated meteorological observations to investigate the transport of northern hemispheric pollutants over the Pacific. We focus on carbon monoxide (CO) and tag it in the model by its region of origin. The model reproduces the observed large-scale latitudinal, longitudinal, and vertical gradients of CO concentrations over the Pacific. Biomass burning in Southeast Asia, which was particularly intense in spring 1999, contributed most of the CO enhancements observed in the free troposphere over the northern tropical Pacific but played only a minor role in the boundary layer. Fossil fuel combustion in Europe and Asia contributed most of the observed CO enhancements in the boundary layer over the North Pacific; the European influence dominated over Asian influence north of 35degreesN. European influence over the Pacific is particularly strong in spring because of wintertime accumulation of CO at high latitudes. North American pollution made little contribution to CO anywhere over the Pacific. Circulation of Eurasian industrial pollution around the Pacific High and into the trade winds produced a tropical "river of pollution" flowing in the lower troposphere from the northeastern to the western equatorial Pacific and in the vicinity of the South Pacific Convergence Zone. This pathway, however, made little contribution to interhemispheric exchange. Elevated concentrations observed for CO and other northern hemispheric tracers in the upper troposphere over the southeastern Pacific provide evidence for efficient interhemispheric exchange through a narrow region of upper tropospheric westerlies in the eastern equatorial Pacific (the "westerly duct"). We find that this westerly duct was the most important pathway for global interhemispheric exchange during PEM-Tropics B. It was particularly well developed because of the La Nina conditions. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Staudt, AC (reprint author), Harvard Univ, Div Engn & Appl Sci, 29 Oxford St, Cambridge, MA 02138 USA. EM acs@io.harvard.edu NR 64 TC 72 Z9 74 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32571 EP 32589 DI 10.1029/2001JD900078 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100062 ER PT J AU Pickering, KE Thompson, AM Kim, H DeCaria, AJ Pfister, L Kucsera, TL Witte, JC Avery, MA Blake, DR Crawford, JH Heikes, BG Sachse, GW Sandholm, ST Talbot, RW AF Pickering, KE Thompson, AM Kim, H DeCaria, AJ Pfister, L Kucsera, TL Witte, JC Avery, MA Blake, DR Crawford, JH Heikes, BG Sachse, GW Sandholm, ST Talbot, RW TI Trace gas transport and scavenging in PEM-Tropics B South Pacific convergence zone convection SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WESTERN NORTH PACIFIC; OZONE PRODUCTION; DEEP CONVECTION; LOWER STRATOSPHERE; UPPER TROPOSPHERE; CLOUD; MODEL; NOX; AIR; PHOTOCHEMISTRY AB Analysis of chemical transport on Flight 10 of the 1999 Pacific Exploratory Mission (PEM) Tropics B mission clarifies the role of the South Pacific Convergence Zone (SPCZ) in establishing ozone and other trace gas distributions in the southwestern tropical Pacific. The SPCZ is found to be a barrier to mixing in the lower troposphere but a mechanism for convective mixing of tropical boundary layer air from northeast of the SPCZ with upper tropospheric air arriving from the west. A two-dimensional cloud-resolving model is used to quantify three critical processes in global and regional transport: convective mixing, lightning NOx production, and wet scavenging of soluble species. Very low NO and O-3 tropical boundary layer air from the northeastern side of the SPCZ entered the convective updrafts and was transported to the upper troposphere where it mixed with subtropical upper tropospheric air containing much larger NO and O-3 mixing ratios that had arrived from Australia. Aircraft observations show that very little NO appears to have been produced by electrical discharges within the SPCZ convection. We estimate that at least 90% of the HNO3 and H2O2 that would have been in upper tropospheric cloud outflow had been removed during transport through the cloud. Lesser percentages are estimated for less soluble species (e.g., <50% for CH3OOH). Net ozone production rates were decreased in the upper troposphere by similar to60% due to the upward transport and outflow of low-NO boundary layer air. However, this outflow mixed with much higher NO air parcels on the southwest edge of the cloud, and the mixture ultimately possessed a net ozone production potential intermediate between those of the air masses on either side of the SPCZ. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ New Hampshire, Inst Earth Oceans & Space, Durham, NH 03824 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Pickering, KE (reprint author), Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. EM pickering@metosrv2.umd.edu RI Pickering, Kenneth/E-6274-2012; Crawford, James/L-6632-2013; Kim, Hyun/G-1315-2012; Thompson, Anne /C-3649-2014 OI Crawford, James/0000-0002-6982-0934; Kim, Hyun/0000-0003-3968-6145; Thompson, Anne /0000-0002-7829-0920 NR 41 TC 30 Z9 30 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32591 EP 32607 DI 10.1029/2001JD000328 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100063 ER PT J AU Maloney, JC Fuelberg, HE Avery, MA Crawford, JH Blake, DR Heikes, BG Sachse, GW Sandholm, ST Singh, H Talbot, RW AF Maloney, JC Fuelberg, HE Avery, MA Crawford, JH Blake, DR Heikes, BG Sachse, GW Sandholm, ST Singh, H Talbot, RW TI Chemical characteristics of air from different source regions during the second Pacific Exploratory Mission in the Tropics (PEM-Tropics B) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTH ATLANTIC-OCEAN; FEBRUARY-MARCH 1994; WESTERN PACIFIC; CONTINENTAL OUTFLOW; HYDROGEN-PEROXIDE; PEROXYACETYL NITRATE; CONVECTIVE INJECTION; HYDROCARBON RATIOS; UPPER TROPOSPHERE; CONVERGENCE ZONE AB Ten-day back-ward trajectories are used to determine the origins of air parcels arriving at locations of airborne DC-8 chemical measurements during NASA's second Pacific Exploratory Mission in the Tropics B that was conducted during February-April 1999. Chemical data at sites where the trajectories had a common geographical origin and transport history are grouped together, and statistical measures of chemical characteristics are computed. Temporal changes in potential temperature are used to determine whether trajectories experienced a significant convective influence during the 10-day period. Trajectories describing the aged marine Southern Hemispheric category remain over the South Pacific Ocean during the 10-day period, and their corresponding chemical signature indicates very clean air. The category aged marine air in the Northern Hemisphere is found to be somewhat dirtier. Subdividing its trajectories based on the direction from which the air had traveled is found to be important in explaining the various chemical signatures. Similarly, long-range northern hemispheric trajectories passing over Asia are subdivided depending on whether they had followed a mostly zonal path, had originated near the Indian Ocean, or had originated near Central or South America and subsequently experienced a stratospheric influence. Results show that the chemical signatures of these subcategories are different from each other. The chemical signature of the southern hemispheric long-range transport category apparently exhibits the effects of pollution from Australia, southern Africa, and South America. Parcels originating over Central and northern South America are found to contain the strongest pollution signature of all categories, due to biomass burning and other sources. The convective category exhibits enhanced values of nitrogen species, probably due to emissions from lightning associated with the convection. Values of various species, including peroxides and acids, confirm that parcels were influenced by the removal of soluble gas and particle species due to precipitation. Finally, current results are compared with those from the first PEM-Tropics mission that was conducted in the same region during the southern hemispheric dry season (August-October 1996) when extensive biomass burning occurred. Results show that air samples during PEM-Tropics B are considerably cleaner than those of its dry season counterpart. C1 Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Georgia Inst Technol, Dept Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. RP Fuelberg, HE (reprint author), Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. EM fuelberg@met.fsu.edu RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 57 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32609 EP 32625 DI 10.1029/2001JD900100 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100064 ER PT J AU Blake, NJ Blake, DR Simpson, IJ Lopez, JP Johnston, NAC Swanson, AL Katzenstein, AS Meinardi, S Sive, BC Colman, JJ Atlas, E Flocke, F Vay, SA Avery, MA Rowland, FS AF Blake, NJ Blake, DR Simpson, IJ Lopez, JP Johnston, NAC Swanson, AL Katzenstein, AS Meinardi, S Sive, BC Colman, JJ Atlas, E Flocke, F Vay, SA Avery, MA Rowland, FS TI Large-scale latitudinal and vertical distributions of NMHCs and selected halocarbons in the troposphere over the Pacific Ocean during the March-April 1999 Pacific Exploratory Mission (PEM-Tropics B) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTERCOMPARISON EXPERIMENT NOMHICE; NONMETHANE HYDROCARBONS; WESTERN PACIFIC; AIRCRAFT MEASUREMENTS; SEASONAL-VARIATIONS; SOUTH-PACIFIC; CHEMICAL CHARACTERISTICS; ANTARCTIC TROPOSPHERE; CARBON-MONOXIDE; ALKYL NITRATES AB Nonmethane hydrocarbons (NMHCs) and selected halocarbons were measured in whole air samples collected over the remote Pacific Ocean during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-Tropics B (PEM-Tropics B) in March and early April 1999. The large-scale spatial distributions of NMHCs and C2Cl4 reveal a much more pronounced north-south interhemispheric gradient, with higher concentrations in the north and lower levels in the south, than for the late August to early October 1996 PEM-Tropics A experiment. Strong continental outflow and winter-long accumulation of pollutants led to seasonally high Northern Hemisphere trace gas levels during PEM-Tropics B. Observations of enhanced levels of Halon 1211 (from developing Asian nations such as the PRC) and CH3Cl (from SE Asian biomass burning) support a significant southern Asian influence at altitudes above I kin and north of 10degreesN. By contrast, at low altitude over the North Pacific the dominance of urban/industrial tracers, combined with low levels of Halon 1211 and CH3Cl indicate a greater influence from developed nations such as Japan, Europe, and North America. Penetration of air exhibiting aged northern hemisphere characteristics was frequently observed at low altitudes over the equatorial central and western Pacific south to similar to5degreesS. The relative lack of southern hemisphere biomass burning sources and the westerly position of the South Pacific convergence zone contributed to significantly lower PEM-Tropics B mixing ratios of the NMHCs and CH3Cl south of 10degreesS compared to PEM-Tropics A. Therefore the trace gas composition of the South Pacific troposphere was considerably more representative of minimally polluted tropospheric conditions during PEM-Tropics B. C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Blake, NJ (reprint author), Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. EM nblake@uci.edu; drblake@uci.edu; isimpson@uci.edu; jplopez@uci.edu; jonah@kokopelli.lanl.gov; aswanson@ea.oac.uci.edu; akatzens@uci.edu; smeinard@uci.edu; Barkley.C.Sive@cmich.edu; atlas@acd.ucar.edu; ffl@acd.ucar.edu RI Atlas, Elliot/J-8171-2015 NR 44 TC 39 Z9 39 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32627 EP 32644 DI 10.1029/2000JD900773 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100065 ER PT J AU Lefer, BL Hall, SR Cinquini, L Shetter, RE Barrick, JD Crawford, JH AF Lefer, BL Hall, SR Cinquini, L Shetter, RE Barrick, JD Crawford, JH TI Comparison of airborne NO2 photolysis frequency measurements during PEM-Tropics B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ACTINIC FLUX SPECTRORADIOMETRY; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; PHOTOSTATIONARY STATE; CROSS-SECTIONS; OZONE; ATMOSPHERE; TEMPERATURE; COEFFICIENT; ACTINOMETER; RATES AB During the NASA Pacific Exploratory Mission - Tropics B (PEM-Tropics B) the NO2 photolysis frequency was simultaneously measured by colocated National Center for Atmospheric Research scanning actinic flux spectroradiometer (SAFS) and commercial filter radiometer (FR) instruments on the NASA DC-8 and the NASA P-3B research aircraft. The measurements were collected from early March to mid-April 1999 over the Pacific Ocean, spanning the region between 35degreesN-25degreesS latitude and 80degreesW-170degreesE Longitude. Over the course of the mission the SAFS and FR instruments performed quite well with both systems reporting data for more than 85% of the PEM-Tropics B flight hours. For both the SAFS and FR systems the reported total jNO(2) is the sum of the signals from independent zenith and nadir viewing, instruments. The 1-min average SAFS and FR jNO(2) values were quite highly correlated (r(2) > 0.98) for both the zenith and nadir systems in this complex radiation environment. During PEM-Tropics B these instruments exhibited a difference ranging from 5 to 40% (depending on the instrument pair), with the jNO(2) FR measurements always being higher. In contrast, a consistent 30% disagreement was observed for the SAYS and FR instruments during PEM-Tropics A. Use of newer NO2 cross-section data would increase the SAFS jNO(2) by 4%, while the larger difference between one of the FR and SAFS instrument pairs could be related to a change in the FR instrument sensitivity. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80305 USA. NASA, Langley Res Ctr, Chem & Dynam Branch, Hampton, VA 23681 USA. RP Lefer, BL (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80305 USA. EM lefer@ucar.edu RI Crawford, James/L-6632-2013; Lefer, Barry/B-5417-2012 OI Crawford, James/0000-0002-6982-0934; Lefer, Barry/0000-0001-9520-5495 NR 24 TC 10 Z9 10 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32645 EP 32656 DI 10.1029/2001JD900114 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100066 ER PT J AU Tan, D Faloona, I Simpas, JB Brune, W Olson, J Crawford, J Avery, M Sachse, G Vay, S Sandholm, S Guan, HW Vaughn, T Mastromarino, J Heikes, B Snow, J Podolske, J Singh, H AF Tan, D Faloona, I Simpas, JB Brune, W Olson, J Crawford, J Avery, M Sachse, G Vay, S Sandholm, S Guan, HW Vaughn, T Mastromarino, J Heikes, B Snow, J Podolske, J Singh, H TI OH and HO2 in the tropical Pacific: Results from PEM-Tropics B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LASER-INDUCED FLUORESCENCE; UPPER TROPOSPHERE; PHOTOCHEMISTRY; CHEMISTRY; MECHANISM; HYDROXYL; RADICALS; HO(X) AB OH and HO2 data collected on NASA's Pacific Exploratory Mission - Tropics B (PEM-Tropics B) are presented here and compared to results from a photochemical box model. PEM-Tropics B took place in the tropical Pacific in March and April of 1999 and examined photochemistry and sulfur chemistry in the remote tropical atmosphere. Altitude-resolved HOx budgets are presented. The model showed good overall agreement with the data, with a mean model to observed ratio of 0.86 for OH and 1.03 for HO2. The model tends to underpredict OH at higher altitudes and overpredict at low altitudes. The model agrees well with the HO2 observations at middle altitudes but tends to overpredict slightly at high and low altitudes. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Langley, VA USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Tan, D (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM dtan@eas.gatech.edu; brune@essc.psu.edu RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 20 TC 44 Z9 45 U1 2 U2 24 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32667 EP 32681 DI 10.1029/2001JD900002 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100068 ER PT J AU Davis, D Grodzinsky, G Chen, G Crawford, J Eisele, F Mauldin, L Tanner, D Cantrell, C Brune, W Tan, D Faloona, I Ridley, B Montzka, D Walega, J Grahek, F Sandholm, S Sachse, G Vay, S Anderson, B Avery, M Heikes, B Snow, J O'Sullivan, D Shetter, R Lefer, B Blake, D Blake, N Carroll, M Wang, Y AF Davis, D Grodzinsky, G Chen, G Crawford, J Eisele, F Mauldin, L Tanner, D Cantrell, C Brune, W Tan, D Faloona, I Ridley, B Montzka, D Walega, J Grahek, F Sandholm, S Sachse, G Vay, S Anderson, B Avery, M Heikes, B Snow, J O'Sullivan, D Shetter, R Lefer, B Blake, D Blake, N Carroll, M Wang, Y TI Marine latitude/altitude OH distributions: Comparison of Pacific Ocean observations with models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PHOTOSTATIONARY STATE ANALYSIS; METHANE SULFONIC-ACID; WESTERN NORTH PACIFIC; LONG-RANGE TRANSPORT; IN-SITU MEASUREMENTS; TROPOSPHERIC OH; TROPICAL PACIFIC; PEM-TROPICS; PHOTOCHEMISTRY EXPERIMENT; BOUNDARY-LAYER AB Reported here are tropical/subtropical Pacific basin OH observational data presented in a latitude/altitude geographical grid. They cover two seasons of the year (spring and fall) that reflect the timing of NASA's PEM-Tropics A (1996) and B (1999) field programs. Two different OH sensors were used to collect these data, and each instrument was mounted on a different aircraft platform (i.e., NASA's P-3B and DC-8). Collectively, these chemical snapshots of the central Pacific have revealed several interesting trends. Only modest decreases (factors of 2 to 3) were found in the levels of OH with increasing altitude (0-12 km). Similarly, only modest variations were found (factors of 1.5 to 3.5) when the data were examined as a function of latitude (30degreesN to 30degreesS). Using simultaneously recorded data for CO, O-3, H2O, NO, and NMHCs, comparisons with current models were also carried out. For three out of four data subsets, the results revealed a high level of correspondence. On average, the box model results agreed with the observations within a factor of 1.5. The comparison with the three-dimensional model results was found to be only slightly worse. Overall, these results suggest that current model mechanisms capture the major photochemical processes controlling OH quite well and thus provide a reasonably good representation of OH levels for tropical marine environments. They also indicate that the two OH sensors employed during the PEM-Tropics B study generally saw similar OH levels when sampling a similar tropical marine environment. However, a modest altitude bias appears to exist between these instruments. More rigorous instrument intercomparison activity would therefore seem to be justified. Further comparisons of model predictions with observations are also recommended for nontropical marine environments as well as those involving highly elevated levels of reactive non-methane hydrocarbons. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. USN Acad, Dept Chem, Annapolis, MD 21402 USA. Univ New Hampshire, Inst Study Earth Ocean & Space, Durham, NH 03824 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08903 USA. RP Davis, D (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM douglas.davis@eas.gatech.edu RI Crawford, James/L-6632-2013; Wang, Yuhang/B-5578-2014; Lefer, Barry/B-5417-2012; OI Crawford, James/0000-0002-6982-0934; Lefer, Barry/0000-0001-9520-5495; O'Sullivan, Daniel/0000-0001-9104-5703 NR 60 TC 17 Z9 18 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32691 EP 32707 DI 10.1029/2001JD900141 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100070 ER PT J AU Ravetta, F Jacob, DJ Brune, WH Heikes, BG Anderson, BE Blake, DR Gregory, GL Sachse, GW Sandholm, ST Shetter, RE Singh, HB Talbot, RW AF Ravetta, F Jacob, DJ Brune, WH Heikes, BG Anderson, BE Blake, DR Gregory, GL Sachse, GW Sandholm, ST Shetter, RE Singh, HB Talbot, RW TI Experimental evidence for the importance of convected methylhydroperoxide as a source of hydrogen oxide (HOx) radicals in the tropical upper troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UNITED-STATES; CHEMISTRY; PACIFIC; NOX; OZONE; PHOTOCHEMISTRY; PEROXIDES; TRANSPORT; INJECTION; HO(X) AB Concurrent measurements of OH, HO2, H2O2, and CH3OOH concentrations were made during an aircraft flight over the tropical South Pacific that followed a back-and-forth pattern at constant 10 km altitude for 4 hours. One end of the pattern sampled an aged convective outflow, while the other end sampled the background atmosphere. Concentrations of HO2 and CH3OOH in the convective outflow were elevated by 50 and 350% relative to background, respectively, while concentrations of OH and H2O2 were not elevated. The high CH3OOH concentrations in the outflow were due to convective pumping from the marine boundary layer. In contrast to CH3OOH, H2O2 was not enhanced in the outflow because its high water solubility allows efficient scavenging in the convective updraft. A photochemical model calculation constrained with the ensemble of aircraft observations reproduces the HO2 enhancement in the convective outflow and attributes it to the enhanced CH3OOH; the calculation also reproduces the lack of OH enhancement in the outflow and attributes it to OH loss from reaction with CH3OOH. Further analysis of model results shows substantial evidence that the rate constant used in standard mechanisms for the CH3O2 + HO2 reaction is about a factor of 3 too low at the low temperatures of the upper troposphere. A sensitivity simulation using a value of 3.4 x 10(-11) cm(3) molecule(-1) s(-1) at 233 K for this rate constant yields better agreement with observed HO2 concentrations and better closure of the chemical budgets for both CH3OOH and H2O2. The CH3O2 + HO2 reaction then becomes the single most important loss pathway for HOx radicals (HOx = OH + peroxy radicals) in the upper troposphere. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Rhode Isl, Ctr Atmospher Chem Studies, Kingston, RI 02881 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. RP Ravetta, F (reprint author), Univ Paris 06, CNRS, IPSL, Serv Aeron, F-75252 Paris 05, France. EM francois.ravetta@aero.jussieu.fr NR 20 TC 27 Z9 28 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32709 EP 32716 DI 10.1029/2001JD900009 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100071 ER PT J AU Heikes, B Snow, J Egli, P O'Sullivan, D Crawford, J Olson, J Chen, G Davis, D Blake, N Blake, D AF Heikes, B Snow, J Egli, P O'Sullivan, D Crawford, J Olson, J Chen, G Davis, D Blake, N Blake, D TI Formaldehyde over the central Pacific during PEM-Tropics B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; PHOTOCHEMISTRY EXPERIMENT 2; UPPER TROPOSPHERE; SOUTH ATLANTIC; OXYGENATED HYDROCARBONS; CONVECTIVE INJECTION; CARBONYL-COMPOUNDS; FORMIC-ACID; HYDROPEROXIDES; AIR AB Formaldehyde, CH2O, mixing ratios are reported for the central Pacific troposphere from a series of 41 flights, which took place in March-April 1999 as part of the NASA Pacific Exploratory Mission (PEM)-Tropics B mission. Ambient CH2O was collected in aqueous media and quantified using an enzyme-derivatization fluorescence technique. Primary calibration was performed using aqueous standards and known flow rates. Occasionally, CH2O gas standard additions to ambient air were performed as a secondary calibration. Analytical blanks were determined by replacing ambient air with pure air. The estimated precision was +/-30 pptv and the estimated accuracy was the sum of +/-30 parts per trillion by volume (pptv) +/-15% of the measured value. Approximately 25% of the observations were less than the instrumental detection limit of 50 pptv, and 85% of these occurred above 6 km. CH2O mixing ratios decreased with altitude; for example, near the equator the median value in the lowest 2 km was 275 pptv, decreased to 150 pptv by 6 kin and was below 100 pptv above 8 km. Between 130 and 170 W and below 1 km, a small variation of CH2O mixing ratio with latitude was noted as near-surface median mixing ratios decreased near the equator (275 pptv) and were greater on either side (375 pptv). A marked decrease in near-surface CH2O (200 pptv) was noted south of 23degreesS on two flights. Between 3degrees and 23degreesS, median CH2O mixing ratios were lower in the eastern tropical Pacific than in the western or central Pacific; nominal differences were >100 pptv near the surface to similar to100 pptv at midaltitude to similar to50 pptv at high attitude. Off the coast of Central America and Mexico, mixing ratios as high as 1200 pptv were observed in plumes that originated to the east over land. CH2O observations were consistently higher than the results from a point model constrained by other photochemical species and meteorological parameters. Regardless of latitude or longitude, agreement was best at altitudes above 4 kin where the difference between measured and modeled CH2O medians was less than 50 pptv. Below 2 km in the model median was approximately 150 pptv less than the measured median. C1 Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. USN Acad, Dept Chem, Annapolis, MD 21402 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ New Hampshire, Dept Chem, Durham, NH 03824 USA. RP Heikes, B (reprint author), Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. EM zagar@notos.gso.uri.edu RI Crawford, James/L-6632-2013; OI Crawford, James/0000-0002-6982-0934; O'Sullivan, Daniel/0000-0001-9104-5703 NR 38 TC 22 Z9 22 U1 4 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32717 EP 32731 DI 10.1029/2001JD900012 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100072 ER PT J AU Wang, YH Liu, SC Wine, PH Davis, DD Sandholm, ST Atlas, EL Avery, MA Blake, DR Blake, NJ Brune, WH Heikes, BG Sachse, GW Shetter, RE Singh, HB Talbot, RW Tan, D AF Wang, YH Liu, SC Wine, PH Davis, DD Sandholm, ST Atlas, EL Avery, MA Blake, DR Blake, NJ Brune, WH Heikes, BG Sachse, GW Shetter, RE Singh, HB Talbot, RW Tan, D TI Factors controlling tropospheric O-3, OH, NOx and SO2 over the tropical Pacific during PEM-Tropics B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GLOBAL SIMULATION; SOUTH-PACIFIC; PHOTOCHEMISTRY EXPERIMENT; NONMETHANE HYDROCARBONS; CONVECTIVE INJECTION; OZONE; CHEMISTRY; ORIGIN; MODEL; DISTRIBUTIONS AB Observations over the tropical Pacific during the Pacific Exploratory Mission (PEM)-Tropics B experiment (March-April 1999) are analyzed. Concentrations of CO and long-lived nonmethane hydrocarbons in the region are significantly enhanced due to transport of pollutants from northern industrial continents. This pollutant import also enhances moderately O-3 concentrations but not NOx concentrations. It therefore tends to depress OH concentrations over the tropical Pacific. These effects contrast to the large enhancements of O-3 and NOx concentrations and the moderate increase of OH concentrations due to biomass burning outflow during the PEM-Tropics A experiment (September-October 1996). Observed CH3I concentrations, as in PEM-Tropics A, indicate that convective mass outflux in the middle and upper troposphere is largely independent of altitude over the tropical Pacific. Constraining a one-dimensional model with CH3I observations yields a 10-day timescale for convective turnover of the free troposphere, a factor of 2 faster than during PEM-Tropics A. Model simulated HO2, CH2O, H2O2, and CH3OOH concentrations are generally in agreement with observations. However, simulated OH concentrations are lower (similar to25%) than observations above 6 kin. Whereas models tend to overestimate previous field measurements, simulated HNO3 concentrations during PEM-Tropics B are too low (a factor of 2-4 below 6 km) compared to observations. Budget analyses indicate that chemical production of O-3 accounts for only 50% of chemical loss; significant transport of O-3 into the region appears to take place within the tropics. Convective transport of CH3OOH enhances the production of HOx and O-3 in the upper troposphere, but this effect is offset by HOx loss due to the scavenging of H2O2. Convective transport and scavenging of reactive nitrogen species imply a necessary source of 0.4-1 Tg yr(-1) of NOx in the free troposphere (above 4 km) over the tropics. A large fraction of the source could be from marine lightning. Oxidation of DMS transported by convection from the boundary layer could explain the observed free tropospheric SO2 concentrations over the tropical Pacific. This source of DMS due to convection, however, would imply in the model free tropospheric concentrations much higher than observed. The model overestimate cannot be reconciled using recent kinetics measurements of the DMS-OH adduct reaction at low pressures and temperatures and may reflect enhanced OH oxidation of DMS during convection. C1 Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30332 USA. RP Wang, YH (reprint author), Rutgers State Univ, Dept Environm Sci, 14 Coll Farm Rd, New Brunswick, NJ 08901 USA. EM yhw@envsci.rutgers.edu RI Wang, Yuhang/B-5578-2014; Wine, Paul/J-4820-2015; Atlas, Elliot/J-8171-2015 OI Wine, Paul/0000-0002-5537-4304; NR 45 TC 28 Z9 28 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32733 EP 32747 DI 10.1029/2001JD900084 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100073 ER PT J AU Olson, JR Crawford, JH Davis, DD Chen, G Avery, MA Barrick, JDW Sachse, GW Vay, SA Sandholm, ST Tan, D Brune, WH Faloona, IC Heikes, BG Shetter, RE Lefer, BL Singh, HB Talbot, RW Blake, DR AF Olson, JR Crawford, JH Davis, DD Chen, G Avery, MA Barrick, JDW Sachse, GW Vay, SA Sandholm, ST Tan, D Brune, WH Faloona, IC Heikes, BG Shetter, RE Lefer, BL Singh, HB Talbot, RW Blake, DR TI Seasonal differences in the photochemistry of the South Pacific: A comparison of observations and model results from PEM-Tropics A and B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PHOTOSTATIONARY STATE ANALYSIS; TROPOSPHERIC OZONE BUDGET; BOUNDARY-LAYER EXPERIMENT; WESTERN NORTH PACIFIC; AIRBORNE OBSERVATIONS; EXPLORATORY MISSION; CONVECTIVE INJECTION; LOWER STRATOSPHERE; HYDROGEN RADICALS; NITROGEN-OXIDES AB A time-dependent photochemical box model is used to examine the photochemistry of the equatorial and southern subtropical Pacific troposphere with aircraft data obtained during two distinct seasons: the Pacific Exploratory Mission-Tropics A (PEM-Tropics A) field campaign in September and October of 1996 and the Pacific Exploratory Mission-Tropics B (PEM-Tropics B) campaign in March and April of 1999. Model-predicted values were compared to observations for selected species (e.g., NO2, OH, HO2) with generally good agreement. Predicted values of HO2 were larger than those observed in the upper troposphere, in contrast to previous studies which show a general underprediction of HO2 at upper altitudes. Some characteristics of the budgets of HOx, NOx, and peroxides are discussed. The integrated net tendency for O-3 is negative over the remote Pacific during both seasons, with gross formation equal to no more than half of the gross destruction. This suggests that a continual supply of O-3 into the Pacific region throughout the year must exist in order to maintain O-3 levels. Integrated net tendencies for equatorial O-3 showed a seasonality, with a net loss of 1.06 x 10(11) molecules cm(-2) s(-1) during PEM-Tropics B (March) increasing by 50% to 1.60 x 10(11) molecules cm(-2) s(-1) during PEM-Tropics A (September). The seasonality over the southern subtropical Pacific was somewhat lower, with losses of 1.21 x 10(11) molecules cm(-2) s(-1) during PEM-Tropics B (March) increasing by 25% to 1.51 x 10(11) molecules cm(-2) s(-1) during PEM-Tropics A (September). While the larger net losses during PEM-Tropics A were primarily driven by higher concentrations of O-3, the ability of the subtropical atmosphere to destroy O-3 was similar to30% less effective during the PEM-Tropics A (September) campaign due to a drier atmosphere and higher overhead O-3 column amounts. C1 NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23665 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem, Narragansett, RI 02882 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Chem & Dynam Branch, Moffett Field, CA 94035 USA. Univ New Hampshire, EOS, CSRC, Durham, NH 03824 USA. RP Olson, JR (reprint author), NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23665 USA. EM j.r.olson@larc.nasa.gov RI Crawford, James/L-6632-2013; Lefer, Barry/B-5417-2012 OI Crawford, James/0000-0002-6982-0934; Lefer, Barry/0000-0001-9520-5495 NR 70 TC 36 Z9 36 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32749 EP 32766 DI 10.1029/2001JD900077 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100074 ER PT J AU Weber, RJ Moore, K Kapustin, V Clarke, A Mauldin, RL Kosciuch, E Cantrell, C Eisele, F Anderson, B Thornhill, L AF Weber, RJ Moore, K Kapustin, V Clarke, A Mauldin, RL Kosciuch, E Cantrell, C Eisele, F Anderson, B Thornhill, L TI Nucleation in the equatorial Pacific during PEM-Tropics B: Enhanced boundary layer H2SO4 with no particle production SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONDENSATION NUCLEUS COUNTER; AEROSOL FORMATION; ACE 1; BINARY NUCLEATION; SIZE DISTRIBUTION; FREE-TROPOSPHERE; SULFURIC-ACID; MARINE CLOUDS; ATMOSPHERE; RATES AB During the second phase of the NASA Pacific Exploratory Mission to the Pacific Tropics (PEM-Tropics B), regions of unusually high concentrations of sulfuric acid vapor ranging from 107 to 108 Molecules CM. were detected near the ocean surface in equatorial regions between Hawaii and Tahiti. No 3-4 nm diameter nanoparticles were observed near the ocean surface where acid concentrations were highest; however, 3-4 nm particles were detected at higher elevations in regions near clouds. Calculations show that in some regions of high acid concentrations newly formed particles would be readily detected by our instruments and thus the lack of nanoparticles suggests that there was no nucleation. In contrast, in the previous PEM-Tropics A mission Clarke et al. [1998a] observed a large nucleation event in the equatorial marine boundary layer under similar temperatures, relative humidity, and sulfuric acid concentrations. Comparison between these two studies further demonstrates that some additional species or unknown process is necessary to significantly enhance nucleation in the remote marine troposphere and that this component is not always present at levels sufficient to sustain nucleation throughout the region, even at a low continuous rate. We speculate that if ammonia is one example of a critical nucleation precursor, tropospheric ternary nucleation (sulfuric acid/ammonia/water) under some conditions requires ammonia concentrations to be greater than typical background concentrations for particle production via this mechanism. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NCAR, Boulder, CO 80303 USA. Univ Hawaii, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. RP Weber, RJ (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM rweber@eas.gatech.edu NR 43 TC 15 Z9 15 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2001 VL 106 IS D23 BP 32767 EP 32776 DI 10.1029/2001JD900250 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 515DA UT WOS:000173479100075 ER PT J AU Reinisch, BW Huang, X Song, P Sales, GS Fung, SF Green, JL Gallagher, DL Vasyliunas, VM AF Reinisch, BW Huang, X Song, P Sales, GS Fung, SF Green, JL Gallagher, DL Vasyliunas, VM TI Plasma density distribution along the magnetospheric field: RPI observations from IMAGE SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ELECTRON-DENSITIES; MAGNETIC-FIELD; IONOSPHERE; MODEL AB A new technique is introduced that remotely measures the plasma density profile in the plasmasphere. Radio plasma imager (RPI) echo observations provide echo delay time as function of frequency, from which the plasma density as function of position along the magnetic field line can be calculated. An example from the nightside plasmasphere (L=3) shows the density having its minimum value near the equator and rapidly increasing densities along the field line above 40 degrees magnetic latitude, The density increases at a faster rate toward the ionosphere than the field strength. The index of the power law of the density as a function of field strength increases from a few tenths near the equator to close to unity near 40 degrees and greater than 2 near the ionosphere. C1 Univ Massachusetts, Environm Earth & Atmospher Sci Dept, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35805 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RP Reinisch, BW (reprint author), Univ Massachusetts, Environm Earth & Atmospher Sci Dept, Ctr Atmospher Res, Lowell, MA 01854 USA. RI Fung, Shing/F-5647-2012 NR 19 TC 73 Z9 73 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 DEC 15 PY 2001 VL 28 IS 24 BP 4521 EP 4524 DI 10.1029/2001GL013684 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 507KA UT WOS:000173025400003 ER PT J AU Sanderson, TR Marsden, RG Tranquille, C Balogh, A Forsyth, RJ Goldstein, BE Gosling, JT Harvey, KL AF Sanderson, TR Marsden, RG Tranquille, C Balogh, A Forsyth, RJ Goldstein, BE Gosling, JT Harvey, KL TI The influence of the Sun's magnetic field on energetic particles at high heliospheric latitudes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SECTOR STRUCTURE; SOLAR-WIND; ULYSSES AB The first passage of the Ulysses spacecraft to high latitudes was during the declining phase of solar cycle 22. The recent second passage to high latitudes was close to the maximum of solar cycle 23. The axis of the dipolar component of the Sun's magnetic field was close to 90 degrees from the spin axis, and the coronal neutral line extended up to high latitudes. A variable but generally slow solar wind was observed all the way up to the highest latitudes reached by Ulysses, as was the sector structure of the magnetic field. The high-latitude heliosphere was populated with intensities of energetic particles with energies around 1 MeV several orders of magnitude above background. We show how the changes in the Sun's magnetic field, the coronal holes, and the configuration of the heliosphere could be responsible for the differences between particle observations in the two orbits. C1 European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. Los Alamos Natl Lab, Los Alamos, NM USA. Solar Phys Res Corp, Tucson, AZ USA. RP Sanderson, TR (reprint author), European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. NR 11 TC 4 Z9 4 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 DEC 15 PY 2001 VL 28 IS 24 BP 4525 EP 4528 DI 10.1029/2001GL013146 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 507KA UT WOS:000173025400004 ER PT J AU Cess, RD Zhang, MG Wang, PH Wielicki, BA AF Cess, RD Zhang, MG Wang, PH Wielicki, BA TI Cloud structure anomalies over the tropical Pacific during the 1997/98 El Nino SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Satellite measurements of both cloud vertical structure and cloud-radiative forcing have been used to show that during the strong 1997/98 El Nino there was a substantial change in cloud vertical structure over the tropical Pacific Ocean. Relative to normal years, cloud altitudes were lower in the western portion of the Pacific and higher in the eastern portion. The reason for these redistributions was a collapse of the Walker circulation and enhanced large-scale upward motion over the eastern Pacific, both caused by the lack of a zonal sea surface temperature gradient during the El Nino. It is proposed that these cloud structure changes, which significantly impact satellite measurements of the tropical Pacific's radiation budget, would serve as one useful means of testing cloud-climate interactions in climate models. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Sci & Technol Corp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cess, RD (reprint author), SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. NR 7 TC 31 Z9 31 U1 0 U2 2 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 DEC 15 PY 2001 VL 28 IS 24 BP 4547 EP 4550 DI 10.1029/2001GL013750 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 507KA UT WOS:000173025400010 ER PT J AU Prigent, C Matthews, E Aires, F Rossow, WB AF Prigent, C Matthews, E Aires, F Rossow, WB TI Remote sensing of global wetland dynamics with multiple satellite data sets SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FLOODPLAIN; AREA AB This study is the first global effort to quantify seasonality and extent of inundation with a suite of satellite observations, including passive and active microwave along with visible and infrared measurements. A clustering technique which merges the satellite observations is used to detect inundation. Monthly flooded areas are then calculated by estimating pixel fractional coverage of flooding using the passive microwave signal and a linear mixture model with end-members calibrated with radar observations to account for vegetation cover. The global results, comprising natural wetlands, irrigated rice, and lakes/rivers, indicate a minimum inundated area for the July 1992-June 1993 period of 2.16 x 10(6) km(2), about 38% of the maximum 5.75 x 10(6) km(2), to be compared to maximum areas of 5.83 x 10(6) km(2) and 5.70 x 10(6) km(2) from independent data sets. Comprehensive evaluation requires substantial additions to the sparse observational record now available. C1 Observ Paris, Dept Radioastronomie Millimetr, Paris, France. NASA, Goddard Inst Space Studies, New York, NY USA. RP Prigent, C (reprint author), Observ Paris, Dept Radioastronomie Millimetr, Paris, France. RI Rossow, William/F-3138-2015 NR 11 TC 102 Z9 105 U1 4 U2 42 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 DEC 15 PY 2001 VL 28 IS 24 BP 4631 EP 4634 DI 10.1029/2001GL013263 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 507KA UT WOS:000173025400031 ER PT J AU Ferguson, FT Heist, RH Nuth, JA AF Ferguson, FT Heist, RH Nuth, JA TI The effect of carrier gas pressure and wall heating on the operation of the thermal diffusion cloud chamber SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HOMOGENEOUS NUCLEATION RATES; N-PENTANOL; BACKGROUND GASES; VAPORS AB Experimental observations indicate that the nucleation behavior within the thermal diffusion cloud chamber (TDCC) changes with increasing carrier gas pressure and applied sidewall heating, even though such an effect is not predicted by typical nucleation theories and it is not seen in typical expansion-based nucleation studies. In this work we present a model of the chamber which shows that both of these effects are likely due to buoyancy-induced convection within the TDCC. As the chamber pressure is increased, the calculated critical supersaturation within the chamber decreases. Results from a simple model of the chamber wall heating are also presented. Previously, it was argued that unheated chamber walls result in a significant, radial concentration gradient which lowers the vapor concentration and condensation flux within the chamber center. In contrast, we show that this reduction is due primarily to a convective flow induced by the sidewall concentration gradient. The model has been applied to recent experimental data for n-pentanol. Results indicate that, with respect to buoyancy-induced convection, the typical 1D model should be regarded as an upper limit to the maximum attainable supersaturation within the chamber. (C) 2001 American Institute of Physics. C1 Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. Manhattan Coll, Dept Chem Engn, Bronx, NY 10471 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ferguson, FT (reprint author), Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. RI Ferguson, Frank/C-9493-2012; Nuth, Joseph/E-7085-2012 NR 23 TC 14 Z9 14 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 15 PY 2001 VL 115 IS 23 BP 10829 EP 10836 DI 10.1063/1.1409956 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 498WF UT WOS:000172536000029 ER PT J AU Hirose, N Fukumori, I Zlotnicki, V Ponte, RM AF Hirose, N Fukumori, I Zlotnicki, V Ponte, RM TI Modeling the high-frequency barotropic response of the ocean to atmospheric disturbances: Sensitivity to forcing, topography, and friction SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-LEVEL VARIABILITY; GLOBAL OCEAN; SATELLITE ALTIMETRY; PRESSURE AB This study examines high-frequency sea level variations forced by changes in surface atmospheric pressure and wind and their sensitivity to different forcing mechanisms, bottom topography resolution, and amount of friction in a barotropic ocean model. Optimal model performance, defined in terms of the explained variance in satellite altimeter and bottom pressure data, is found when using relatively strong friction, equivalent to a damping timescale of only a few days over the deep ocean, and topography with minimal smoothing. Spatial variations of the optimal friction parameter seem to reflect the roughness of bottom topography. The model demonstrates skill in simulating the wind-driven response as well as the nonequilibrium response to atmospheric pressure variations. C1 Kyushu Univ, Appl Mech Res Inst, Dynam Simulat Res Ctr, Kasuga, Fukuoka 8168580, Japan. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hirose, N (reprint author), Kyushu Univ, Appl Mech Res Inst, Dynam Simulat Res Ctr, 6-1 Kasuga Kouen, Kasuga, Fukuoka 8168580, Japan. RI Kyushu, RIAM/F-4018-2015; U-ID, Kyushu/C-5291-2016; OI Hirose, Naoki/0000-0001-6234-8676; Ponte, Rui/0000-0001-7206-6461 NR 18 TC 45 Z9 47 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2001 VL 106 IS C12 BP 30987 EP 30995 DI 10.1029/2000JC000763 PG 9 WC Oceanography SC Oceanography GA 513WB UT WOS:000173402400005 ER PT J AU Hoge, FE Wright, CW Lyon, PE Swift, RN Yungel, JK AF Hoge, FE Wright, CW Lyon, PE Swift, RN Yungel, JK TI Inherent optical properties imagery of the western North Atlantic Ocean: Horizontal spatial variability of the upper mixed layer SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DISSOLVED ORGANIC-MATTER; SATELLITE RETRIEVAL; RADIANCE MODEL; FLUORESCENCE MEASUREMENTS; ABSORPTION-COEFFICIENT; GULF-STREAM; MATRIX-INVERSION; CAPE-HATTERAS; CHLOROPHYLL; BIGHT AB Until now, no satellite methods were available for the study of inherent optical properties (IOPs) over wide areas of the world's oceans. Herein the coefficients of phytoplankton absorption, chromophoric dissolved organic matter (CDOM)-detritus absorption, and total backscattering have been retrieved from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) 412, 490, and 555 run reflectances by linear matrix inversion of an oceanic radiance model. The retrieved phytoplankton absorption coefficient from an October 6, 1997, image of the Middle Atlantic Bight (MAB) reveals (1) characteristic patchiness over the shelf, slope, Gulf Stream, and Sargasso Sea, (2) a warm-core ring being encircled by a spiral streamer of phytoplankton-containing cooler shelf water, and (3) phytoplankton prominence at South Atlantic Bight capes and remarkable minima between the capes. The retrieved CDOM-detritus absorption coefficient image readily shows (1) the characteristic offshore 20x decline from similar to0.4 to 0.02(-1), (2) a sharp drop at the Gulf Stream NW boundary, (3) striations of CDOM-detritus within the Gulf Stream, and (4) that during the fall, non-bloom season, the dominant absorbing constituent over the MAB continental shelf is not phytoplankton but CDOM-detritus. The retrieved total backscattering coefficient image shows a patchy depression over the middle to outer shelf (compared to the Gulf Stream and inner shelf). A feature common to all three inherent optical property images is the northeasterly extrusion of phytoplankton, CDOM-detritus, and other constituents from Cape Hatteras coastal/shelf water along a streamer adjacent to the Gulf Stream. No similar evidence of shelf water export was observed over the Diamond Shoals area south of Cape Hatteras where previous researchers have reported episodic offshore advection of shelf water. A second mechanism for carbon export can be seen in the New York Bight where a tongue of outflow from the Hudson River can be seen to cross the shelf and interact with the northern wall of a warm-core ring. A concurrent 150 m altitude airborne underflight with a calibrated ocean-viewing 256-channel spectroradiometer provided supplementary atmospheric correction to the SeaWiFS remote sensing reflectances and validation of the resulting SeaWiFS IOP retrievals. Simultaneous airborne lidar fluorescence was used to confirm further the SeaWiFS CDOM-detritus and phytoplankton absorption coefficient IOP retrievals. The results strongly suggest that if satisfactory atmospheric correction can eventually be achieved without airborne underflights, then the SeaWiFS data will readily allow global-scale IOP variability studies. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EG&G Inc, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NR 35 TC 18 Z9 18 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2001 VL 106 IS C12 BP 31129 EP 31140 DI 10.1029/1999JC000132 PG 12 WC Oceanography SC Oceanography GA 513WB UT WOS:000173402400015 ER PT J AU Wilson, C Adamec, D AF Wilson, C Adamec, D TI Correlations between surface chlorophyll and sea surface height in the tropical Pacific during the 1997-1999 El Nino-Southern Oscillation event SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID CENTRAL EQUATORIAL PACIFIC; OCEAN; IRON; VARIABILITY; PRODUCTIVITY; TEMPERATURE; PATTERNS; SEAWIFS; ONSET; LEVEL AB Correlations between Sea-viewing Wide Field-of-view Sensor (SeaWiFS) surface chlorophyll and TOPER sea surface height (SSH) are examined in the tropical Pacific (30degreesS-30degreesN) using empirical orthogonal function (EOF) analysis both separately and jointly on the two fields. This analysis is done on data from September 1997, the start of data from the SeaWiFS satellite, through December 1999, a time period dominated by the El Nino-Southern Oscillation. Four distinct biological responses are observed. The dominant response is a symmetric off-equatorial chlorophyll increase during La Nina that extends between 2degrees and 18degrees latitude from the eastern Pacific to the date line. The chlorophyll mode is tightly correlated to SSH, suggesting that the chlorophyll increase is a result of the shoaling thermocline, which increases the surface nutrient supply. The better known equatorial decrease in chlorophyll during El Nino is seen in a separate EOF mode. Using acoustic Doppler current profiler data from the Tropical Atmosphere-Ocean/Triton array, it is shown that the cessation of the El Nino equatorial chlorophyll minimum is tied to the recommencement of the iron-rich Equatorial Undercurrent which occurs several months prior to the termination of the El Nino. There is an off-equatorial bloom during the peak of the El Nino between 120degreesW-180degreesW and 8degreesN-15degreesN. This bloom occurs within the area covered by the previously mentioned La Nina bloom, but it is more localized, and its fluctuations appear correlated with changes in the North Equatorial Counter Current. The shoaling thermocline in the western warm pool during El Nino results in a chlorophyll bloom that extends from the Philippines to 155degreesE between 0degreesN and 15degreesN. This bloom terminates in unison with the end of the El Nino when elevated SSH is reestablished in the western basin. C1 NASA, Goddard Space Flight Ctr, GEST Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Wilson, C (reprint author), NASA, Goddard Space Flight Ctr, GEST Ctr, Code 971, Greenbelt, MD 20771 USA. RI Wilson, Cara/A-8816-2009 NR 49 TC 59 Z9 61 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2001 VL 106 IS C12 BP 31175 EP 31188 DI 10.1029/2000JC000724 PG 14 WC Oceanography SC Oceanography GA 513WB UT WOS:000173402400019 ER PT J AU Signorini, SR McClain, CR Christian, JR Wong, CS AF Signorini, SR McClain, CR Christian, JR Wong, CS TI Seasonal and interannual variability of phytoplankton, nutrients, TCO2, pCO(2), and O-2 in the eastern subarctic Pacific (ocean weather station Papa) SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GAS-EXCHANGE; BIOLOGICAL PROCESSES; NORTH PACIFIC; CARBONIC-ACID; MIXED-LAYER; WIND-SPEED; SEA; CO2; SEAWATER; AIR AB A coupled, one-dimensional ecosystem/carbon flux model is used to simulate the seasonal and interannual variability of phytoplankton, nutrients, TCO2, O-2, and pCO(2) at ocean weather station Papa (OWS P at 50degreesN, 145degreesW). The 23-year interannual simulation (1958-1980) is validated with available data and analyzed to extend seasonal and interannual variations beyond the limited observational records. The seasonal cycles of pCO(2) and sea-air CO2 flux are controlled by a combination of thermodynamics, winds, and biological uptake. There is ingassing of CO2 during the fall-winter months when SSTs are colder and wind forcing is vigorous, while there is a much smaller ingassing of CO2 during the summer when sea surface temperatures are warmer and wind speeds are reduced. Biological production plays a major role in maintaining the air-sea equilibrium. An abiotic simulation showed that OWS P would be a source of atmospheric CO2 (1.41 mol C m(-2) yr(-1)) if the biological sink of CO2 were removed. The peak net community production in summer compensates for the increased temperature effect on pCO(2), which prevents large outgassing in summer. Oxygen anomalies relative to the temperature-determined saturation value show that there is a seasonal cycle of air-sea flux, with ingassing in winter and outgassing in summer. The net surface oxygen flux is positive (0.8 mol m(-2) yr(-1)), indicating that OWS P is a source of oxygen to the atmosphere. The average primary production is 167 g C m(-2) yr(-1). The 1960-1980 (1958 and 1959 spin-up years removed) mean carbon flux is -1.8 mol C m(-2) yr(-1), indicating that the ocean at OWS P is a sink of atmospheric carbon. The sea-air CO2 flux ranges from -1.2 to -2.3 mol C m(-2) yr(-1) during the 21-year simulation period. This finding emphasizes the need for long-term observations to accurately determine carbon flux budgets. A series of sensitivity experiments indicate that the seasonal variability and overall (21 years) mean of TCO2, pCO(2), DeltapCO(2), and air-sea CO2 flux are strongly dependent on the gas transfer formulation adopted, the total alkalinity near the surface, and the bottom (350 m) value adopted for TCO2. The secular atmospheric pCO(2) upward trend is manifested in the TCO2 concentration within the upper 100 m by an increase of 15 mmol m(-3) in 20 years, consistent with observations at other locations [Winn et al., 1998; Bates, 2001]. C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, SeaWiFS Project, Greenbelt, MD 20771 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, SeaWiFS Project Off, Lab Hydropher Proc, Greenbelt, MD 20771 USA. Fisheries Oceans Canada Inst Ocean Sci, Climate Chem Lab, Sidney, BC V8L 4B2, Canada. RP NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, SeaWiFS Project, Code 970-2,Bldg 28, Greenbelt, MD 20771 USA. EM sergio@bluefin.gsfc.nasa.gov; mcclain@calval.gsfc.nasa.gov; jrc@barolo.essic.umd.edu; wongcs@pac.dfompo.gc.ca NR 48 TC 23 Z9 23 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2001 VL 106 IS C12 BP 31197 EP 31215 DI 10.1029/2000JC000343 PG 19 WC Oceanography SC Oceanography GA 513WB UT WOS:000173402400021 ER PT J AU Comiso, JC Steffen, K AF Comiso, JC Steffen, K TI Studies of Antarctic sea ice concentrations from satellite data and their applications SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WEDDELL SEA; MICROWAVE OBSERVATIONS; IN-SITU; WINTER; IMAGERY; VARIABILITY; PARAMETERS; SIGNATURES; ALGORITHM; COVER AB Large regional and temporal changes in the global sea ice cover have been observed recently. Because of the relevance of such changes to climate change studies it is important that key ice concentration data sets currently used for evaluating such a phenomenon are assessed for accuracy and interpreted properly. Sea ice concentrations derived from passive microwave data using the Bootstrap and NASA Team algorithms are shown to be generally consistent but are also observed to differ by 10-35% in large areas within the ice pack, especially in the Weddell Sea, Amundsen Sea, and Ross Sea regions. Comparative analyses of such passive microwave data with coregistered visible and infrared (i.e., Landsat, AVHRR, and OLS) data show a predominance of thick consolidated ice in these areas and good agreement with the Bootstrap algorithm results. The relatively low values from the NASA Team algorithm results are likely due to layering within the ice and snow and/or surface flooding, which are known to affect the polarization ratio. Large seasonality in the physical characteristics and emissivity of the ice cover is also observed, and in predominantly new ice regions, the ice concentrations from passive microwave data are usually lower than retrievals from Landsat and OLS data in which the thresholding technique is used. The passive microwave results are biased because of relatively low emissivity of new ice, but they may be more useful since the bias allows for the identification of areas of significant divergence and polynya activities. Such areas need to be identified since heat and salinity fluxes are proportionately increased in these areas compared to those from the thicker ice areas. Time series data from 1978 through 2000 also show a slight but insignificant positive trend of 0.17 +/- 0.33%/decade in ice extent which is consistent with slight continental cooling during the period. This is a big contrast to the observed negative trend of about -3%/decade in the Arctic sea ice cover. It should be noted, however, that because the overlap period for key instruments is just 1 month, the error due to changes in sensor characteristics, calibration, and threshold for the 15% ice edge may not be negligible. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. RI Steffen, Konrad/C-6027-2013 OI Steffen, Konrad/0000-0001-8658-1026 NR 47 TC 35 Z9 36 U1 2 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2001 VL 106 IS C12 BP 31361 EP 31385 DI 10.1029/2001JC000823 PG 25 WC Oceanography SC Oceanography GA 513WB UT WOS:000173402400031 ER PT J AU Huterer, D Turner, MS AF Huterer, D Turner, MS TI Probing dark energy: Methods and strategies SO PHYSICAL REVIEW D LA English DT Article ID MICROWAVE BACKGROUND ANISOTROPIES; SMALL COSMOLOGICAL CONSTANT; STRING-DOMINATED UNIVERSE; LY-ALPHA FOREST; COSMIC EQUATION; REDSHIFT SURVEYS; IA SUPERNOVAE; STATE; QUINTESSENCE; CLUSTERS AB The presence of dark energy in the Universe is infer-red directly from the accelerated expansion of the Universe, and, indirectly, from measurements of cosmic microwave background (CMB) anisotropy. Dark energy contributes about two-thirds of the critical density, is smoothly distributed, has large negative pressure, and is very mysterious. For now, all of its discernible cosmological consequences follow from its effect on the expansion rate of the Universe. Absent a compelling theoretical model (or even a class of models), we describe the dark energy by its equation of state w=p(X)/rho (X) which is allowed to vary with time. We describe and compare different approaches for determining w(t), including a magnitude-redshift (Hubble) diagram, number counts of galaxies and clusters, and CMB anisotropy. We focus particular attention on the use of a sample of several thousand type Ia supernova with redshifts z less than or similar to1.7, as might be gathered by the proposed SNAP satellite. Among other things, we derive optimal strategies for constraining cosmological parameters using type la supernovae. The redshift range z similar or equal to0.2-2 has the most leverage for probing w(X); supernovae and number counts appear to have the most potential to probe dark energy. Because the expansion rate depends upon both w(t) and Omega (M), an independent measurement of the matter density is critical for obtaining the most information about dark energy from cosmological observations. C1 Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. NR 89 TC 303 Z9 304 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 2001 VL 64 IS 12 AR 123527 DI 10.1103/PhysRevD.64.123527 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 504QJ UT WOS:000172867100037 ER PT J AU Fahnestock, M Abdalati, W Joughin, I Brozena, J Gogineni, P AF Fahnestock, M Abdalati, W Joughin, I Brozena, J Gogineni, P TI High geothermal heat row, basal melt, and the origin of rapid ice how in central Greenland SO SCIENCE LA English DT Article ID SHEET; ELEVATION; STREAM; GISP2; MODEL; CORE; FLOW AB Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental background. The southern limit of melt coincides with magnetic anomalies and topography that suggest a volcanic origin. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. NASA, Washington, DC 20546 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Kansas, Remote Sensing Lab, Lawrence, KS 66045 USA. RP Fahnestock, M (reprint author), Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RI Joughin, Ian/A-2998-2008; Fahnestock, Mark/N-2678-2013 OI Joughin, Ian/0000-0001-6229-679X; NR 30 TC 114 Z9 116 U1 1 U2 30 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 14 PY 2001 VL 294 IS 5550 BP 2338 EP 2342 DI 10.1126/science.1065370 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 503TT UT WOS:000172817200042 PM 11743197 ER PT J AU Aspin, C Sandell, G AF Aspin, C Sandell, G TI Further evidence for the FU Orionis nature of PP13S SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE stars : formation; stars : individual : PP13S; stars : mass-loss; stars : pre-main-sequence; ISM : jets and outflows ID STARS; TELESCOPE; NEBULAE; CAMERA AB We present optical and near-infrared images and spectroscopy together with submillimetre images of the candidate FU Orionis pre-main-sequence star PP 13S. A comparison of historical plates with our new images shows that PP 13S has dimmed and changed optical morphology significantly over the last half-century. In addition, its optical spectrum has undergone dramatic changes over a period of 18 yr from one dominated by strong continuum emission to one showing only ionized, shock-excited emission lines. The current association with several features indicative of both accretion and outflow suggests that, within the last few hundred years, PP 13S passed through an elevated emission state characteristic of the high-accretion events of known FU Orionis-type stars, and has since declined, over the last few decades, to a more quiescent state. The result of the outburst may well have been the formation of the shock-excited Herbig-Haro jet seen to extend from the obscured young star. We additionally see significant morphological evolution of the source PP 13N. Its apparent association with a Herbig-Haro flow suggests that it also is actively accreting and driving a bipolar outflow. C1 Univ Oxford, Nucl Phys Lab, Oxford OX1 3RH, England. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Aspin, C (reprint author), Gemini Observ, 670 N Aohoku Pl, Hilo, HI 96720 USA. NR 30 TC 12 Z9 12 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD DEC 11 PY 2001 VL 328 IS 3 BP 751 EP 761 DI 10.1046/j.1365-8711.2001.04687.x PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505PW UT WOS:000172925600008 ER PT J AU Canuto, VM Minotti, F AF Canuto, VM Minotti, F TI Mixing and transport in stars - I. Formalism: momentum, heat and mean molecular weight SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE turbulence; stars : rotation ID STELLAR TURBULENT CONVECTION; DIFFERENTIAL ROTATION; MAIN-SEQUENCE; MERIDIONAL CIRCULATION; LITHIUM DEPLETION; SOLAR CONVECTION; SHEAR TURBULENCE; INTERNAL WAVES; MODEL; TACHOCLINE AB The goal of this paper is to derive analytic expressions for the turbulent fluxes of momentum (Reynolds stresses), heat and mean molecular weight. (i) Angular momentum. To solve the angular momentum equation one needs to know the Reynolds stresses R-ij, in particular R-phir. It is shown that the latter has the form R-r phi = -2D(s)S(phir) - 2D(v)V(phir) - D(0)Ohm (0) - D(1)Ohm+ ..., where 2S(phir) = sin thetar partial derivative Omega/partial derivativer is the shear and 2rV(phir) = sin theta partial derivative (r(2)Ohm)/partial derivativer is the vorticity. The dots indicate buoyancy and meridional currents. The forms of the turbulent diffusivities entering the shear part D-s, vorticity part D-v, rigid rotation Ohm (0) and differential rotation Omega = Omega (r, theta) are also derived. Previous models have only the shear term. The vorticity term gives rise to a true diffusion-like equation for the angular momentum which now reads partial derivative/partial derivativet(r(2)Ohm) = r(-2)partial derivative/partial derivativer(r(4)D(s) partial derivative Omega/partial derivativer) + r(-2) partial derivative/partial derivativer [r(2)D(v) partial derivative/partial derivativer (r(2)Ohm)] + .... (ii) Mean temperature equation. Differential rotation alters the mean temperature equation. In the stationary case, the new flux conservation law reads (chi is the radiative diffusivity) del + K(h)chi (-1)(del - del (ad)) + del Omega = del (r), where the new term is given by del (Omega) = (H-p/c(p)chiT)R-r phi<()over bar>(phi). (iii) Tensorial diffusivities. The turbulent flux of a scalar phi (like T and mu) is shown to have the form J(i)(phi) = -D-ij(phi) partial derivative Phi/partial derivativex(j), where the D-ij are tensorial diffusivities. They are shown to be functions of the external source of energy (e.g. flux of gravity waves), rigid-body rotation, differential rotation, meridional currents, T-mu gradients and Peclet number Pe which characterizes the role of radiative losses. (iv) Mixing and advection. The tensorial nature of the diffusivities D-ij has an immediate consequence: the symmetric part D-ij(s) gives rise to mixing (by diffusion) while the antisymmetric part D-ij(a) gives rise to advection which cannot be represented by a diffusion coefficient. The equation describing a mean scalar field Phi is therefore partial derivative Phi/partial derivativet + (<()over bar> + u*) del Phi = partial derivative/partial derivativex(i) (D-ij(s) partial derivative Phi/partial derivativex(j)), u(i)* = partial derivative/partial derivativex(j)D(ij)(a). Thus even without a mean velocity field Phi there is an advective term u* arising from turbulence alone. The advective nature of turbulence was not accounted for in previous studies which have therefore underestimated the full potential of turbulent motion. (v) Peclet number dependence. Radiative losses are an important part of the physical picture, for they weaken the temperature gradient, and thus reduce the effect of stable stratification and ultimately enhance mixing. The Peclet number dependence is accounted for in the model. (vi) Shear-induced versus wave-induced mixing. In this formalism, the dichotomy between the two processes no longer exists, since we show that the flux of gravity waves, treated as an external source of energy, is a natural ingredient of the formalism. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys & Math, New York, NY 10027 USA. Univ Buenos Aires, CONICET, Dept Phys, RA-1053 Buenos Aires, DF, Argentina. Univ Buenos Aires, CONICET, Dept Plasma Phys, RA-1053 Buenos Aires, DF, Argentina. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM acvmc@giss.nasa.gov NR 44 TC 8 Z9 8 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD DEC 11 PY 2001 VL 328 IS 3 BP 829 EP 838 DI 10.1046/j.1365-8711.2001.04911.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505PW UT WOS:000172925600015 ER PT J AU Murphy, TP Lyon, RG Dorband, JE Hollis, JM AF Murphy, TP Lyon, RG Dorband, JE Hollis, JM TI Sparse matrix approximation met hod for an active optical control system SO APPLIED OPTICS LA English DT Article ID ADAPTIVE-OPTICS; PHASE RETRIEVAL; TELESCOPES; ALGORITHM AB We develop a sparse matrix approximation method to decompose a wave front into a: basis set of actuator influence functions for an active optical system consisting of a deformable mirror and a segmented primary mirror. The wave front used is constructed by Zernike polynomials to simulate the output of a phase-retrieval algorithm. Results of:a Monte Carlo simulation of the optical control loop are compared with the standard, nonsparse approach in terms of accuracy and precision, as well as computational speed and memory. The sparse matrix approximation method can yield more than a 50-fold increase in the speed and a 20-fold reduction in matrix size and a commensurate decrease in required memory, with less than 10% degradation in solution accuracy. Our method is also shown to be better than when elements are selected for the sparse matrix on a magnitude basis alone. We show that the method developed is a viable alternative to use of the full control matrix in a phase-retrieval-based active optical control system. (C) 2001 Optical Society of America. C1 Sci Workstn, Silver Spring, MD 20902 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Murphy, TP (reprint author), Sci Workstn, 718 N Belgrade Court, Silver Spring, MD 20902 USA. EM lyon@jansky.gsfc.nasa.gov NR 19 TC 4 Z9 4 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 10 PY 2001 VL 40 IS 35 BP 6505 EP 6514 DI 10.1364/AO.40.006505 PG 10 WC Optics SC Optics GA 500ZG UT WOS:000172658100009 PM 18364958 ER PT J AU Carson, JE Larkin, JE McLean, IS Graham, JR Becklin, EE Figer, DF Gilbert, AM Levenson, NA Teplitz, HI Wilcox, MK AF Carson, JE Larkin, JE McLean, IS Graham, JR Becklin, EE Figer, DF Gilbert, AM Levenson, NA Teplitz, HI Wilcox, MK TI Resolved infrared spectroscopy of two high-redshift radio galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : high-redshift; galaxies : individual (4C 40.36, 4C 48.48); infrared : galaxies ID EMISSION-LINE GAS; EVOLUTION AB We report on the rest-frame optical-line emission from the extended gas in two high-redshift radio galaxies, 4C 48.48 at z = 2.343 and 4C 40.36 at z = 2.265. These are among the first observations to obtain rest-frame optical spectra for distinct knots of gas within a high-redshift radio galaxy. Although the dominant ionization mechanism in both sources is photoionization by the central AGNs, we find evidence of another mechanism within the off-nuclear emission of each source. We measure [O II], [Ne III] and [O III] for several regions in 4C 48.48; these measurements indicate shock ionization in one region. We measure seven lines in 4C 40.36 and compare the on- and off-nuclear emission from the two strongest, H alpha and [O III]; we find that [O III]/H alpha is at least a factor of 4 weaker off-nucleus, suggesting star formation in the extended region. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Carson, JE (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 23 TC 8 Z9 8 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2001 VL 563 IS 1 BP 63 EP 70 DI 10.1086/323833 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JC UT WOS:000172852700006 ER PT J AU Keck, JW Craig, WW Hailey, CJ Harrison, F Hong, JS Kahn, SM Lubin, PM McLean, R Pivovaroff, MJ Seiffert, M Wurtz, R Ziock, KP AF Keck, JW Craig, WW Hailey, CJ Harrison, F Hong, JS Kahn, SM Lubin, PM McLean, R Pivovaroff, MJ Seiffert, M Wurtz, R Ziock, KP TI Long-term multiwavelength observations of GRS 1758-258 and the advection-dominated accretion flow model SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; gamma rays : observations; radio continuum : stars; stars : individual (GRS 1758-258); X-rays : stars ID X-RAY SOURCE; BLACK-HOLE; SOURCE GRS-1758-258; COMPTONIZATION MODELS; INTERSTELLAR-MEDIUM; NEUTRON-STARS; GX-339-4; 1E-1740.7-2942; STATE; SPECTROSCOPY AB We present a long-term multiwavelength light curve of Galactic black hole candidate GRS 1758-258 by combining previously published and archival data from Granat, ROSAT, the Compton Gamma Ray Observatory, the Rossi X-Ray Timing Explorer, BeppoSAX, ASCA, EXOSAT, and the Very Large Array. In addition, we include the first spectral results from the balloon-borne Gamma-Ray Arcminute Telescope Imaging System (GRAT IS). In light of divergent analyses of the 1991-1993 ROSAT observations, we have reanalyzed these data; we find that the soft X-rays track the hard X-rays and that the fits require no blackbody component-indicating that GRS 1758-258 did not go to the high state in 1993. We offer an interpretation of these long-baseline data based on the advection-dominated accretion flow (ADAF) model for a system with m over dot less than or similar to m over dot(crit). We find that the 1990-1993 coeval hard and soft X-ray observations support the ADAF predictions. We discuss a new way to constrain black hole mass with spectral data and the ADAF theory and apply this technique to GRS 1758-258 to find M (1) greater than or similar to 8-9 M. at an assumed distance of 8.5 kpc. Further investigations of the ADAF model allow us to evaluate the model critically against the 1996 data and flux-flux diagram of Barret, McClintock, & Grindlay and to understand the limits of the latter's "X-ray burster box." C1 Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Keck, JW (reprint author), Columbia Univ, Columbia Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. RI Pivovaroff, Michael/M-7998-2014 OI Pivovaroff, Michael/0000-0001-6780-6816 NR 56 TC 6 Z9 6 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2001 VL 563 IS 1 BP 301 EP 312 DI 10.1086/323686 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JC UT WOS:000172852700029 ER PT J AU Bhatia, AK Saba, JLR AF Bhatia, AK Saba, JLR TI Resonance scattering of Fe XVII X-ray and extreme-ultraviolet lines SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; scattering; Sun : UV radiation; X-rays : general ID TRANSMISSION GRATING SPECTROMETER; NEON-LIKE IONS; SOLAR-FLARE; ACTIVE-REGION; COLLISION STRENGTHS; ABSORPTION LINES; SPECTRAL-LINES; CROSS-SECTIONS; ABUNDANCES; RATIOS AB Over the years, a number of calculations have been carried out to derive intensities of various X-ray and extreme-ultraviolet (EUV) lines in Fe XVII for comparing with observed spectra. The predicted intensities have not agreed with solar observations, particularly for the line at 15.02 Angstrom; resonance scattering has been suggested as the source for much of the disagreement. The atomic data calculated earlier by Bhatia & Doschek used seven configurations having n = 3 orbitals, and the scattering calculations were carried out only for incident energies above the threshold of the highest fine-structure level. These calculations have now been extended to thirteen configurations having n = 4 orbitals, and the scattering calculations are carried out below as well as above the threshold of the highest fine-structure level. These improved calculations of Fe XVII change the intensity ratios compared to those obtained earlier, bringing the optically thin F(15.02)/F(16.78) ratio and several other ratios closer to the observed values. However, some disagreement with the solar observations still persists, even though the agreement of the currently calculated optically thin F(15.02)/F(15.26) ratio with the experimental results of Brown and coworkers, and Laming and coworkers has improved. Some of the remaining discrepancy is still thought to be the effect of opacity, which is consistent with expected physical conditions for solar sources. EUV intensity ratios are also calculated and compared with observations. Level populations and intensity ratios are calculated as a function of column density of Fe XVII in the slab and cylindrical geometries. As found previously, the predicted intensities for the resonance lines at 15.02 and 15.26 exhibit initial increases in flux relative to the forbidden line at 17.10 Angstrom and the resonance line at 16.78 Angstrom as optical thickness increases. The same behavior is predicted for the lines at 12.262 and 12.122 Angstrom. Predicted intensities for some of the allowed EUV lines are also affected by opacity. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NASA, Lackheed Martin Solar & Astrophys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 661, Greenbelt, MD 20771 USA. NR 51 TC 19 Z9 19 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 DEC 10 PY 2001 VL 563 IS 1 BP 434 EP 450 DI 10.1086/323688 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JC UT WOS:000172852700044 ER PT J AU Morgenthaler, JP Harris, WM Scherb, F Anderson, CM Oliversen, RJ Doane, NE Combi, MR Marconi, ML Smyth, WH AF Morgenthaler, JP Harris, WM Scherb, F Anderson, CM Oliversen, RJ Doane, NE Combi, MR Marconi, ML Smyth, WH TI Large-aperture [O I] 6300 angstrom photometry of comet Hale-Bopp: Implications for the photochemistry of OH SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : individual (Hale-Bopp 1995 O1, Hyakutake (C/1996 B2)); instrumentation : spectrographs; molecular processes ID HUBBLE-SPACE-TELESCOPE; H2O PRODUCTION-RATES; SPATIAL-DISTRIBUTION; ALPHA OBSERVATIONS; HYDROGEN COMA; C/1996 B2; P-HALLEY; P/HALLEY; WATER; O(1D) AB Large-aperture photometric observations of comet Hale-Bopp (C/1995 O1) in the forbidden red line of neutral oxygen ([O I] 6300 Angstrom) with the 150 mm dual-etalon Fabry-Perot spectrometer that comprises the Wisconsin H alpha Mapper and a 50 mm dual-etalon Fabry-Perot spectrometer at the McMath-Pierce main telescope from 1997 late February to mid April yield a total metastable O(D-1) production rate of (2.3- 5.9) x 10(30) s(-1). Applying the standard H2O and OH photodissociation branching ratios found in Huebner, Keady, & Lyon and van Dishoeck & Dalgarno, we derive a water production rate, of Q(H2O), of (2.6-6.1) x 10(31) s(-1), which disagrees with Q(H2O) approximate to 1 x 10(31) s(-1) determined by independent H2O OH, and H measurements. Furthermore, our own [O I] 6300 Angstrom observations of the inner coma (< 30,000 km) using the 3.5 m Wisconsin-Indiana-Yale-NOAO telescope Hydra and Densepak multi-object spectrographs yield Q(H2O) 1 x 10(31) s(-1). Using our [O I] 6300 data, which cover spatial scales ranging from 2,000 to 1 x 10(6) km, and a complementary set of wide-field ground-based OH images, we can constrain the sources of the apparent excess O(D-1) emission to the outer coma, where photodissociation of OH is assumed to be the dominant O(D-1) production mechanism. From production rates of other oxygen-bearing volatiles (e.g., CO and CO2), we can account for at most 30% of the observed excess O(D-1) emission. Since even less O(D-1) should be coming from other sources (e.g., electron excitation of neutral O and distributed nonnuclear sources of we hypothesize that the bulk of the excess O(D-1) is likely coming from photodissociating OH. Using the experimental OH photodissociation cross section of Nee & Lee at Ly alpha as a guide in modifying the theoretical OH cross sections of van Dishoeck & Dalgarno, we can account for approximate to 60% of the observed O(D-1) excess without requiring major modifications to the other OH branching ratios or the total OH photodissociation lifetime. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Wisconsin, Space Astron Lab, Madison, WI 53706 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon ITSS, Lanham, MD 20706 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Morgenthaler, JP (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. RI Combi, Michael/J-1697-2012 OI Combi, Michael/0000-0002-9805-0078 NR 63 TC 38 Z9 38 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2001 VL 563 IS 1 BP 451 EP 461 DI 10.1086/323773 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JC UT WOS:000172852700045 ER PT J AU Hulleman, F Tennant, AF van Kerkwijk, MH Kulkarni, SR Kouveliotou, C Patel, SK AF Hulleman, F Tennant, AF van Kerkwijk, MH Kulkarni, SR Kouveliotou, C Patel, SK TI A possible faint near-infrared counterpart to the anomalous X-ray pulsar 1E 2259+586 SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : neutron; X-rays : individual (1E 2259+586); X-rays : stars ID SYSTEM; STARS AB We present near-infrared and optical observations of the field of the anomalous X-ray pulsar 1E 2259+586 taken with the Keck telescope. We derive a subarcsecond Chandra position and tie it to our optical reference frame using other stars in the field. We find a very faint source, K-s = 21.7 +/- 0.2 mag, with a position coincident with the Chandra position. We argue that this is the counterpart. In the J, I, and R bands, we derive (2 sigma) limits of 23.8, 25.6, and 26.4 mag, respectively. As with 4U 0142+61, for which a counterpart has previously been found, our results are inconsistent with models in which the source is powered by accretion from a disk but may be consistent with the magnetar model. C1 Univ Utrecht, NL-3508 TA Utrecht, Netherlands. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. RP Hulleman, F (reprint author), Univ Utrecht, POB 80000, NL-3508 TA Utrecht, Netherlands. NR 17 TC 56 Z9 56 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2001 VL 563 IS 1 BP L49 EP L52 DI 10.1086/338478 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JD UT WOS:000172852800012 ER PT J AU Patel, SK Kouveliotou, C Woods, PM Tennant, AF Weisskopf, MC Finger, MH Gogus, E van der Klis, M Belloni, T AF Patel, SK Kouveliotou, C Woods, PM Tennant, AF Weisskopf, MC Finger, MH Gogus, E van der Klis, M Belloni, T TI Chandra observations of the anomalous X-ray pulsar 1E 2259+586 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (1E 2259+586); stars : neutron; X-rays : stars ID ABUNDANCES; CTB-109 AB We present X-ray imaging, timing, and phase-resolved spectroscopy of the anomalous X-ray pulsar 1E 2259+586 using the Chandra X-Ray Observatory. The spectrum is well described by a power-law plus blackbody model with Gamma = 3.6(1), kT(BB) = 0.412(6) keV, and N-H = 0.93(3) x 10(22) cm(-2); we find no evidence for spectral features (0.5-7.0 keV). We derive a new, precise X-ray position for the source and determine its spin period, P = 6.978977(24) s. Time-resolved X-ray spectra show no significant variation as a function of pulse phase. We have detected excess emission beyond 4" from the central source extending to beyond 100", due to the supernova remnant and possibly dust scattering from the interstellar medium. C1 Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, NSSTC, Dept Phys, Huntsville, AL 35805 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Osserv Astron Brera, I-23807 Merate, Lc, Italy. RP Patel, SK (reprint author), Univ Space Res Assoc, NSSTC, SD-50, Huntsville, AL 35805 USA. NR 23 TC 41 Z9 41 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2001 VL 563 IS 1 BP L45 EP L48 DI 10.1086/338476 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 504JD UT WOS:000172852800011 ER PT J AU Zhang, L Subramanian, RS Balasubramaniam, R AF Zhang, L Subramanian, RS Balasubramaniam, R TI Motion of a drop in a vertical temperature gradient at small Marangoni number - the critical role of inertia SO JOURNAL OF FLUID MECHANICS LA English DT Article ID THERMOCAPILLARY MIGRATION; BUBBLE MOTION AB When a drop moves in a uniform vertical temperature gradient under the combined action of gravity and thermocapillarity at small values of the thermal Peclet number, it is shown that inclusion of inertia is crucial in the development of an asymptotic solution for the temperature field. If inertia is completely ignored, use of the method of matched asymptotic expansions, employing the Peclet number (known as the Marangoni number) as the small parameter, leads to singular behaviour of the outer temperature field. The origin of this behaviour can be traced to the interaction of the slowly decaying Stokeslet, arising from the gravitational contribution to the motion of the drop, with the temperature gradient field far from the drop. When inertia is included, and the method of matched asymptotic expansions is used, employing the Reynolds number as a small parameter, the singular behaviour of the temperature field is eliminated. A result is obtained for the migration velocity of the drop that is correct to O(Re-2 log Re). C1 Clarkson Univ, Dept Chem Engn, Potsdam, NY 13699 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res Fluids & Combust, Cleveland, OH 44135 USA. RP Subramanian, RS (reprint author), Clarkson Univ, Dept Chem Engn, Potsdam, NY 13699 USA. NR 23 TC 15 Z9 15 U1 3 U2 4 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD DEC 10 PY 2001 VL 448 BP 197 EP 211 PG 15 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 499PK UT WOS:000172579400008 ER PT J AU Shen, ZK Wang, M Li, YX Jackson, DD Yin, A Dong, DN Fang, P AF Shen, ZK Wang, M Li, YX Jackson, DD Yin, A Dong, DN Fang, P TI Crustal deformation along the Altyn Tagh fault system, western China, from GPS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID CENOZOIC TECTONIC EVOLUTION; CURRENT PLATE MOTIONS; TIEN-SHAN; CONTINENTAL DEFORMATION; SOUTHERN-CALIFORNIA; AUTONOMOUS REGION; ACTIVE TECTONICS; KINEMATIC MODEL; COLLISION ZONE; EASTERN TIBET AB We collected GPS data from the southern Tarim basin, the Qaidam basin, and the western Kunlun Shan region between 1993 and 1998 to determine crustal deformation along the Altyn Tagh fault system at the northern margin of the Tibetan plateau. We conclude from these data that the Altyn Tagh is a left-lateral strike slip fault with a current slip rate of similar to9 mm/yr, in sharp contrast with geological estimates of 20-30 mm/yr. This contrast poses an enigma: because the GPS data cover a wider region than the geologic data, they might be expected to reveal somewhat more slip. We also find that the Tarim and Qaidam basins behave as rigid blocks within the uncertainty of our measurements, rotating clockwise at a rate of similar to11 and similar to4.5 nrad/yr, respectively, with respect to the Eurasia plate. The rotation of the Tarim basin causes convergence across the Tian Shan, increasing progressively westward from similar to6 mm/yr at 87degreesE to similar to18 mm/yr at 77degreesE. Our data and other GPS data suggest that the Indo-Asia collision is mainly accommodated by crustal shortening along the main Himalayan thrust system (similar to53%) and the Tian Shan contractional belt (similar to19%). Eastward extrusion of the Tibetan plateau along the Altyn Tagh and Kunlun faults accommodates only similar to23% of the Indo-Asia. convergence. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. China Seismol Bur, Crustal Deformat Monitoring Ctr 1, Tianjin, Peoples R China. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Cecil H & Ida M Green Inst Geophys & Planetary Ph, La Jolla, CA 92093 USA. RP Shen, ZK (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. EM zshen@ess.ucla.edu; ckzhao@371.net; djzl@shell.tjvan.net.cn; djackson@ucla.edu; yin@ess.ucla.edu; dong@freia.jpl.nasa.gov; pfang@ucsd.edu RI Yin, An/B-3050-2014 NR 77 TC 120 Z9 162 U1 0 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD DEC 10 PY 2001 VL 106 IS B12 BP 30607 EP 30621 DI 10.1029/2001JB000349 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 512JG UT WOS:000173320800012 ER PT J AU Cerf, NJ Iblisdir, S AF Cerf, NJ Iblisdir, S TI Quantum cloning machines with phase-conjugate input modes SO PHYSICAL REVIEW LETTERS LA English DT Article ID STATES; INFORMATION; VARIABLES; AMPLIFIER AB A quantum cloning machine is introduced that yields M identical optimal clones from N replicas of a coherent state and N' replicas of its phase conjugate. It also optimally produces M' = M + N' - N phase-conjugate clones at no cost. For well chosen ratios N'/N, this machine is shown to provide better cloning fidelities than the standard (N + N') --> M cloner. The special cases of the optimal balanced cloner (N = N') and optimal measurement (M = infinity) are investigated. C1 Free Univ Brussels, Ecole Polytech, B-1050 Brussels, Belgium. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cerf, NJ (reprint author), Free Univ Brussels, Ecole Polytech, CP 165, B-1050 Brussels, Belgium. NR 16 TC 28 Z9 29 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 10 PY 2001 VL 87 IS 24 AR 247903 DI 10.1103/PhysRevLett.87.247903 PG 4 WC Physics, Multidisciplinary SC Physics GA 500TD UT WOS:000172642100056 PM 11736541 ER PT J AU Smith, DE Zuber, MT Neumann, GA AF Smith, DE Zuber, MT Neumann, GA TI Seasonal variations of snow depth on Mars SO SCIENCE LA English DT Article ID GENERAL-CIRCULATION MODEL; WATER-VAPOR; SUMMER TEMPERATURES; GLOBAL SURVEYOR; GRAVITY-FIELD; POLAR-CAP; EVOLUTION; CYCLE; ICE; VARIABILITY AB Using topography collected over one martian year from the Mars Orbiter Laser Altimeter on the Mars Global Surveyor (MGS) spacecraft, we have measured temporal changes in the elevation of the martian surface that correlate with the seasonal cycle of carbon dioxide exchange between the surface and atmosphere. The greatest elevation change (1.5 to 2 meters) occurs at high latitudes ( above 80 degrees), whereas the bulk of the mass exchange occurs at tower latitudes (below 75 degrees N and below 73 degrees S). An unexpected period of sublimation was observed during northern hemisphere autumn, coincident with dust storms in the southern hemisphere. Analysis of MGS Doppler tracking residuals revealed temporal variations in the flattening of Mars that correlate with elevation changes. The combined changes in gravity and elevation constrain the average density of seasonally deposited carbon dioxide to be 910 +/- 230 kilograms per cubic meter, which is considerably denser than terrestrial snow. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. MIT, Cambridge, MA 02139 USA. RP Smith, DE (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RI Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 39 TC 137 Z9 144 U1 1 U2 11 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 7 PY 2001 VL 294 IS 5549 BP 2141 EP 2146 DI 10.1126/science.1066556 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 500VQ UT WOS:000172647700044 PM 11739951 ER PT J AU Shindell, DT Schmidt, GA Mann, ME Rind, D Waple, A AF Shindell, DT Schmidt, GA Mann, ME Rind, D Waple, A TI Solar forcing of regional climate change during the maunder minimum SO SCIENCE LA English DT Article ID GENERAL-CIRCULATION MODEL; THERMOHALINE CIRCULATION; ATLANTIC OSCILLATION; GREENHOUSE-GAS; ICE-AGE; OZONE; TEMPERATURE; VARIABILITY; IRRADIANCE; SIMULATION AB We examine the climate response to solar irradiance changes between the late 17th-century Maunder Minimum and the late 18th century. Global average temperature changes are small (about 0.3 degrees to 0.4 degreesC) in both a climate model and empirical reconstructions. However, regional temperature changes are quite large. In the model, these occur primarily through a forced shift toward the low index state of the Arctic Oscillation/North Atlantic Oscillation as solar irradiance decreases. This leads to colder temperatures over the Northern Hemisphere continents, especially in winter (1 degrees to 2 degreesC), in agreement with historical records and proxy data for surface temperatures. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NASA, Inst Space Studies, New York, NY 10025 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22902 USA. Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA. RP Shindell, DT (reprint author), NASA, Inst Space Studies, New York, NY 10025 USA. RI Shindell, Drew/D-4636-2012; Schmidt, Gavin/D-4427-2012; Mann, Michael/B-8472-2017 OI Schmidt, Gavin/0000-0002-2258-0486; Mann, Michael/0000-0003-3067-296X NR 32 TC 434 Z9 457 U1 6 U2 51 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 7 PY 2001 VL 294 IS 5549 BP 2149 EP 2152 DI 10.1126/science.1064363 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 500VQ UT WOS:000172647700046 PM 11739952 ER PT J AU Hodis, HN Mack, WJ Lobo, RA Shoupe, D Sevanian, A Mahrer, PR Selzer, RH Liu, CR Liu, CH Azen, SP AF Hodis, HN Mack, WJ Lobo, RA Shoupe, D Sevanian, A Mahrer, PR Selzer, RH Liu, CR Liu, CH Azen, SP TI Estrogen in the prevention of atherosclerosis - A randomized, double-blind, placebo-controlled trial SO ANNALS OF INTERNAL MEDICINE LA English DT Article ID INTIMA-MEDIA THICKNESS; HORMONE REPLACEMENT THERAPY; CORONARY HEART-DISEASE; COMMON CAROTID-ARTERY; C-REACTIVE PROTEIN; COLESTIPOL-NIACIN THERAPY; POSTMENOPAUSAL WOMEN; CARDIOVASCULAR-DISEASE; MYOCARDIAL-INFARCTION; WALL THICKNESS AB Background: Although observational studies suggest that estrogen replacement therapy (ERT) reduces cardiovascular morbidity and mortality in postmenopausal women, use of unopposed ERT for prevention of coronary heart disease in healthy postmenopausal women remains untested. Objective: To determine the effects of unopposed ERT on the progression of subclinical atherosclerosis in healthy postmenopausal women without preexisting cardiovascular disease. Design: Randomized, double-blind, placebo-controlled trial. Setting: University-based clinic. Patients: 222 postmenopausal women 45 years of age or older without preexisting cardiovascular disease and with low-density lipoprotein cholesterol levels of 3.37 mmol/L or greater (greater than or equal to 130 mg/dL). Intervention: unopposed micronized 17 beta -estradiol (1 mg/d) or placebo. All women received dietary counseling. Women received lipid-lowering medication if their low-density lipoprotein cholesterol level exceeded 4.15 mmol/L (160 mg/dL). Measurements: The rate of change in intima-media thickness of the right distal common carotid artery far wall in computer image processed B-mode ultrasonograms obtained at baseline and every 6 months during the 2-year trial. Results: In a multivariable mixed-effects model, among women who had at least one follow-up measurement of carotid intima-media thickness (n = 199), the average rate of progression of subclinical atherosclerosis was lower in those taking unopposed estradiol than in those taking placebo (-0.0017 mm/y vs. 0.0036 mm/y); the placebo-estradiol difference between average progression rates was 0.0053 mm/y (95% Cl, 0.0001 to 0.0105 mm/y) (P = 0.046). Among women who did not receive lipid-lowering medication (n = 77), the placebo-estradiol difference between average rates of progression was 0.0147 mm/y (Cl, 0.0055 to 0.0240) (P = 0.002). Average rates of progression did not differ between estradiol and placebo recipients who took lipid-lowering medication (n = 122) (P > 0.2). Conclusions: overall, the average rate of progression of subclinical atherosclerosis was slower in healthy postmenopausal women taking unopposed ERT with 17 beta -estradiol than in women taking placebo. Reduction In the progression of subclinical atherosclerosis was seen in women who did not take lipid-lowering medication but not in those who took these medications. C1 Univ So Calif, Atherosclerosis Res Unit, Los Angeles, CA 90033 USA. Kaiser Permanente Med Ctr, Los Angeles, CA 90034 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Columbia Univ, Coll Phys & Surg, New York, NY USA. RP Hodis, HN (reprint author), Univ So Calif, Atherosclerosis Res Unit, 2250 Alcazar St,CSC 132, Los Angeles, CA 90033 USA. FU NIA NIH HHS [R01-AG-18798] NR 54 TC 424 Z9 432 U1 0 U2 2 PU AMER COLL PHYSICIANS PI PHILADELPHIA PA INDEPENDENCE MALL WEST 6TH AND RACE ST, PHILADELPHIA, PA 19106-1572 USA SN 0003-4819 J9 ANN INTERN MED JI Ann. Intern. Med. PD DEC 4 PY 2001 VL 135 IS 11 BP 939 EP 953 PG 15 WC Medicine, General & Internal SC General & Internal Medicine GA 498PN UT WOS:000172520000001 PM 11730394 ER PT J AU Loncaric, J Ryaben'kii, VS Tsynkov, SV AF Loncaric, J Ryaben'kii, VS Tsynkov, SV TI Active shielding and control of noise SO SIAM JOURNAL ON APPLIED MATHEMATICS LA English DT Article DE active shielding; noise control; time-harmonic acoustic fields; the Helmholtz equation; generalized Calderon's potentials; exact volumetric cancellation; general solution; incoming and outgoing waves; near surface control sources; spatial anisotropies; material discontinuities; optimization; Bessel functions ID ENVIRONMENTAL NOISE; BOUNDARY-CONDITIONS; SOUND; VIBRATION AB We present a mathematical framework for the active control of time-harmonic acoustic disturbances. Unlike many existing methodologies, our approach provides for the exact volumetric cancellation of unwanted noise in a given predetermined region of space while leaving unaltered those components of the total acoustic field that are deemed friendly. Our key finding is that for eliminating the unwanted component of the acoustic field in a given area, one needs to know relatively little; in particular, neither the locations nor structure nor strength of the exterior noise sources need to be known. Likewise, there is no need to know the volumetric properties of the supporting medium across which the acoustic signals propagate, except, perhaps, in the narrow area of space near the boundary (perimeter) of the domain to be shielded. The controls are built based solely on the measurements performed on the perimeter of the region to be shielded; moreover, the controls themselves (i.e., additional sources) are also concentrated only near this perimeter. Perhaps as important, the measured quantities can refer to the total acoustic field rather than only to its unwanted component, and the methodology can automatically distinguish between the two. In the paper, we construct a general solution to the aforementioned noise control problem. The apparatus used for deriving the general solution is closely connected to the concepts of generalized potentials and boundary projections of Calderon's type. For a given total wave field, the application of Calderon's projections allows us to definitively split its incoming and outgoing components with respect to a particular domain of interest, which may have arbitrary shape. Then the controls are designed so that they suppress the incoming component for the domain to be shielded or alternatively, the outgoing component for the domain, which is complementary to the one to be shielded. To demonstrate that the new noise control technique is appropriate, we thoroughly work out a two-dimensional model example that allows full analytical consideration. To conclude, we very briefly discuss the numerical (finite-difference) framework for active noise control that has, in fact, already been worked out, as well as some forthcoming extensions of the current work: optimization of the solution according to different criteria that would fit different practical requirements, applicability of the new technique to quasi-stationary problems, and active shielding in the case of the broad-band spectra of disturbances. In the future, the aforementioned finite-difference framework for active noise control is going to be used for analyzing complex configurations that originate from practical designs. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Russian Acad Sci, MV Keldysh Appl Math Inst, Moscow 125047, Russia. Tel Aviv Univ, Sch Math Sci, IL-69978 Tel Aviv, Israel. RP Loncaric, J (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C, Hampton, VA 23681 USA. NR 35 TC 33 Z9 34 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1399 J9 SIAM J APPL MATH JI SIAM J. Appl. Math. PD DEC 4 PY 2001 VL 62 IS 2 BP 563 EP 596 DI 10.1137/S0036139900367589 PG 34 WC Mathematics, Applied SC Mathematics GA 508XL UT WOS:000173115000011 ER PT J AU Simpson, TW Mistree, F AF Simpson, TW Mistree, F TI Kriging models for global approximation in simulation-based multidisciplinary design optimization SO AIAA JOURNAL LA English DT Article ID COMPUTER EXPERIMENTS; SURROGATES AB Response surface methods have been used for a variety of applications in aerospace engineering, particularly in multidisciplinary design optimization. We investigate the use of kriging models as alternatives to traditional second-order polynomial response surfaces for constructing global approximations for use in a real aerospace engineering application, namely, the design of an aerospike nozzle. Our objective is to examine the difficulties in building and using kriging models to create accurate global approximations to facilitate multidisciplinary design optimization. Error analysis of the response surface and kriging models is performed, along with a graphical comparison of the approximations. Four optimization problems are also formulated and solved using both sets of approximation models to gain insight into their use for multidisciplinary design optimization. We find that the kriging models, which use only a constant "global" model and a Gaussian correlation function, yield global approximations that are slightly more accurate than the response surface models. C1 Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA. Penn State Univ, Dept Ind & Mfg Engn, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. Georgia Inst Technol, George W Woodruff Sch Mech Engn, Syst Realizat Lab, Atlanta, GA 30332 USA. RP Simpson, TW (reprint author), Penn State Univ, Dept Mech & Nucl Engn, 207 Hammond Bldg, University Pk, PA 16802 USA. RI UF, MDO/G-8720-2012 NR 45 TC 341 Z9 381 U1 12 U2 75 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 DEC PY 2001 VL 39 IS 12 BP 2233 EP 2241 DI 10.2514/2.1234 PG 9 WC Engineering, Aerospace SC Engineering GA 501YT UT WOS:000172714200001 ER PT J AU Roslon, M Olenick, S Zhou, YY Walther, DC Torero, JL Fernandez-Pello, AC Ross, HD AF Roslon, M Olenick, S Zhou, YY Walther, DC Torero, JL Fernandez-Pello, AC Ross, HD TI Microgravity ignition delay of solid fuels in low-velocity flows SO AIAA JOURNAL LA English DT Article ID FLAME SPREAD; FLAMMABILITY; PYROLYSIS; FLUX AB Experiments have been performed in microgravity and normal gravity to determine the effects of low-velocity airflows on the piloted ignition delay of solid fuels. Natural convection prevents material testing at the low oxidizer velocities encountered in space facilities (similar to0.1 m/s); thus, it is necessary to conduct these tests in reduced gravity. Tests have been conducted with two types of fuels, polymethylmethacrylate (PMMA) and a polypropylene/glass fiber composite, aboard the NASA KC-135 aircraft, under air velocities below those induced by natural convection. The short reduced gravity period (similar to 25 s) provided by the aircraft limits the testing to high external fluxes (similar to 30 kW/m(2)) so that the ignition delay times are shorter than the microgravity time. In normal gravity, the ignition delay and critical heat flux for ignition decrease as the forced-flow velocity decreases, until they reach minimum values that are limited by natural convection. The microgravity data indicate that ignition delay is further reduced as the air velocity is lowered. A theoretical model is used to predict the ignition delay for PMMA at low flow velocities in microgravity. The model predicts that the critical heat flux for ignition at the flow conditions expected in space facilities could be as much as half the value measured in normal gravity. The results are important because they imply that, in space facilities, ignition may occur more easily than in normal gravity. If the results are confirmed by long-term microgravity testing, they may have important implications for the fire safety design of space facilities. C1 Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Univ Maryland, Dept Fire Protect Engn, College Pk, MD 20742 USA. NASA, John H Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RP Roslon, M (reprint author), Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. NR 33 TC 6 Z9 7 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 2001 VL 39 IS 12 BP 2336 EP 2342 DI 10.2514/2.1239 PG 7 WC Engineering, Aerospace SC Engineering GA 501YT UT WOS:000172714200014 ER PT J AU Liu, TS Teduka, N Kameda, M Asai, K AF Liu, TS Teduka, N Kameda, M Asai, K TI Diffusion timescale of porous pressure-sensitive paint SO AIAA JOURNAL LA English DT Article C1 NASA, Langley Res Ctr, Model Syst Branch, Hampton, VA 23665 USA. Tokyo Univ Agr & Technol, Tokyo 1848588, Japan. Natl Aerosp Lab, Adv Measurement Technol Grp, Tokyo 1828522, Japan. RP Liu, TS (reprint author), NASA, Langley Res Ctr, Model Syst Branch, MS 238, Hampton, VA 23665 USA. RI Kameda, Masaharu/B-9965-2013 OI Kameda, Masaharu/0000-0002-1928-1338 NR 12 TC 9 Z9 10 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 2001 VL 39 IS 12 BP 2400 EP 2402 DI 10.2514/2.1249 PG 3 WC Engineering, Aerospace SC Engineering GA 501YT UT WOS:000172714200023 ER PT J AU Rossum, AC Ziegler, MG Meck, JV AF Rossum, AC Ziegler, MG Meck, JV TI Effect of spaceflight on cardiovascular responses to upright posture in a 77-year-old astronaut SO AMERICAN JOURNAL OF CARDIOLOGY LA English DT Article ID PLASMA-CATECHOLAMINES; AGE; RESPONSIVENESS; SENSITIVITY; EXERCISE AB We studied neuroendocrine and hemodynamic responses to standing before and after spaceflight in a 77-year-old male astronaut and compared them with those of 20 younger astronauts. With standing, the older astronaut had greater maintenance of stroke volume and cardiac output, larger increases in plasma norepinephrine levels, but smaller increases in heart rate and peripheral resistance than the younger astronauts, which is a pattern typical of the geriatric population. C1 NASA, Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Phoenix Heart, Glendale, AZ USA. Univ Calif San Diego, Dept Med, San Diego, CA 92103 USA. RP Meck, JV (reprint author), NASA, Johnson Space Ctr, Life Sci Res Labs, SD3, Houston, TX 77058 USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU EXCERPTA MEDICA INC PI NEW YORK PA 650 AVENUE OF THE AMERICAS, NEW YORK, NY 10011 USA SN 0002-9149 J9 AM J CARDIOL JI Am. J. Cardiol. PD DEC 1 PY 2001 VL 88 IS 11 BP 1335 EP + DI 10.1016/S0002-9149(01)02104-X PG 4 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA 499NF UT WOS:000172576700026 PM 11728371 ER PT J AU Convertino, VA Ludwig, DA Elliott, JJ Wade, CE AF Convertino, VA Ludwig, DA Elliott, JJ Wade, CE TI Evidence for central venous pressure resetting during initial exposure to microgravity SO AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY LA English DT Article DE set point; hypovolemia; diuresis; renal function ID PLASMA-VOLUME; ORTHOSTATIC INTOLERANCE; SPACEFLIGHT; SALINE; ENDOCRINE; SPACE AB We measured central venous pressure (CVP); plasma volume (PV); urine volume rate (UVR); renal excretion of sodium (UNa); and renal clearances of creatinine, sodium, and osmolality before and after acute volume infusion to test the hypothesis that exposure to microgravity causes resetting of the CVP operating point. Six rhesus monkeys underwent two experimental conditions in a crossover counterbalance design: 1) continuous exposure to 10 degrees head-down tilt (HDT) and 2) a control, defined as 16 h/day of 80 degrees head-up tilt and 8 h prone. After 48 h of exposure to either test condition, a 120-min course of continuous infusion of isotonic saline (0.4 ml.kg(-1).min(-1) iv) was administered. Baseline CVP was lower (P = 0.011) in HDT (2.3 +/- 0.3 mmHg) compared with the control (4.5 +/- 1.4 mmHg) condition. After 2 h of saline infusion, CVP was elevated (P = 0.002) to a similar magnitude (P = 0.485) in HDT (Delta CVP = 2.7 +/- 0.8 mmHg) and control (Delta CVP = 2.3 +/- 0.8 mmHg) conditions and returned to preinfusion levels 18 h postinfusion in both treatments. PV followed the same pattern as CVP. The response relationships between CVP and UVR and between CVP and UNa shifted to the left with HDT. The restoration of CVP and PV to lower preinfusion levels after volume loading in HDT compared with control supports the notion that lower CVP during HDT may reflect a new operating point about which vascular volume is regulated. These results may explain the ineffective fluid intake procedures currently employed to treat patients and astronauts. C1 USA, Lib Branch, Inst Surg Res, Ft Sam Houston, TX 78234 USA. Univ Texas, Hlth Sci Ctr, San Antonio, TX 78229 USA. Profess Performance Dev Grp Inc, San Antonio, TX 78240 USA. Rothe Dev Inc, San Antonio, TX 78222 USA. Univ N Carolina, Dept Math Sci, Greensboro, NC 27412 USA. NASA, Ames Res Ctr, Moffett Field, CA 95070 USA. RP Convertino, VA (reprint author), USA, Lib Branch, Inst Surg Res, 3400 Rawley E Chambers Ave,Bldg 3611, Ft Sam Houston, TX 78234 USA. NR 19 TC 3 Z9 4 U1 0 U2 0 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6119 J9 AM J PHYSIOL-REG I JI Am. J. Physiol.-Regul. Integr. Comp. Physiol. PD DEC PY 2001 VL 281 IS 6 BP R2021 EP R2028 PG 8 WC Physiology SC Physiology GA 491VR UT WOS:000172131200032 PM 11705789 ER PT J AU Noca, F AF Noca, F TI Added mass in swimming and flying. SO AMERICAN ZOOLOGIST LA English DT Meeting Abstract C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU SOC INTEGRATIVE COMPARATIVE BIOLOGY PI MCLEAN PA 1313 DOLLEY MADISON BLVD, NO 402, MCLEAN, VA 22101 USA SN 0003-1569 J9 AM ZOOL JI Am. Zool. PD DEC PY 2001 VL 41 IS 6 BP 1540 EP 1541 PG 2 WC Zoology SC Zoology GA 529NX UT WOS:000174306500556 ER PT J AU Cullings, K Makhija, S AF Cullings, K Makhija, S TI Ectomycorrhizal fungal associates of Pinus contorta in soils associated with a hot spring in Norris Geyser basin, Yellowstone National Park, Wyoming SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ELEMENTAL ORGANIC-ANALYSIS; MYCORRHIZAL INFECTION; ARBUSCULAR-MYCORRHIZAL; PISOLITHUS-TINCTORIUS; PAXILLUS-INVOLUTUS; LOBLOLLY PINE; TEMPERATURE; FOREST; GROWTH; ACID AB Molecular methods and comparisons of fruiting patterns (i.e., presence or absence of fungal fruiting bodies in different soil types) were used to determine ectomycorrhizal (EM) associates of Pinus contorta in soils associated with a thermal soil classified as ultra-acidic to extremely acidic (pH 2 to 4). EM were sampled by obtaining 36 soil cores from six paired plots (three cores each) of both thermal soils and forest soils directly adjacent to the thermal area. Fruiting bodies (mushrooms) were collected for molecular identification and to compare fruiting body (above-ground) diversity to below-ground diversity. Our results indicate (i) that there were significant decreases in both the level of EM infection (130 +/- 22 EM root tips/core in forest soil; 68 +/- 22 EM root tips/core in thermal soil) and EM fungal species richness (4.0 +/- 0.5 species/core in forest soil; 1.2 +/- 0.2 species/core in thermal soil) in soils associated with the thermal feature; (ii) that the EM mycota of thermal soils was comprised of a small set of dominant species and included very few rare Species, while the EM mycota of forest soils contained a few dominant species and several rare EM fungal species, (iii) that Dermocybe phoenecius and a species of Inocybe, which was rare in forest soils, were the dominant EM fungal species in thermal soils; (iv) that other than the single Inocybe species, there was no overlap in the EM fungal communities of the forest and thermal soils; and (v) that the fungal species forming the majority of the above-ground fruiting structures in thermal soils (Pisolithus tinctorius, which is commonly used in remediation of acid soils) was not detected on a single EM root tip in either type of soil. Thus, A tinctorius may have a different role in these thermal soils. Our results suggest that this species may not perform well in remediation of all acid soils and that factors such as pH, soil temperature, and soil chemistry may interact to influence EM fungal community structure. In addition, we identified at least one new species with potential for use in remediation of hot acidic soil. C1 San Francisco State Univ, NASA, Ames Res Ctr, Mt View, CA 94035 USA. RP Cullings, K (reprint author), San Francisco State Univ, NASA, Ames Res Ctr, Mt View, CA 94035 USA. NR 56 TC 16 Z9 17 U1 0 U2 6 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD DEC PY 2001 VL 67 IS 12 BP 5538 EP 5543 DI 10.1128/AEM.67.12.5538-5543.2001 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 497JM UT WOS:000172451800026 PM 11722904 ER PT J AU Pauluhn, A Ruedi, I Solanki, SK Schuhle, U Wilhelm, K Lang, J Thompson, WT Hollandt, J AF Pauluhn, A Ruedi, I Solanki, SK Schuhle, U Wilhelm, K Lang, J Thompson, WT Hollandt, J TI Intercalibration of SUMER and CDS on SOHO. II. SUMER detectors A and B and CDS NIS SO APPLIED OPTICS LA English DT Article ID CORONAL DIAGNOSTIC SPECTROMETER; QUIET SUN; SPECTROGRAPH SUMER; SOLAR AB Results of an intercalibration between the extreme-ultraviolet spectrometers Coronal Diagnostic Spectrometer (CDS) and Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory (SOHO) are reported. The results of the joint observing program Intercal_01 are described, and intercalibration results up to July 2000 of both SUMER detectors A and B and of the CDS Normal Incidence Spectrometer (NIS) are presented. The instruments simultaneously observed radiance of emission lines at the center of the Sun, and three lines have been chosen for intercomparison: He I 584 Angstrom, Mg x 609 Angstrom, and Mg x 624 Angstrom. Initially the same area was observed by both instruments, but, after restrictions were imposed by the scanning mechanism of SUMER in November 1996, the instruments viewed areas of different sizes. Nevertheless, the temporal correlation between the two instruments remained good through June 1998, when contact with the SOHO spacecraft was lost. Until then the CDS instrument measured (33 +/- 5)% and (38 +/- 7)% (+/-1 sigma) higher intensity than SUMER in the He I 584-Angstrom line on average for detectors A and B, respectively. Data from SUMER detector B agreed well for Mg x 609 Angstrom and Mg x 624 Angstrom with the CDS intensities, showing offsets of (2 +/- 10)% and (9 +/- 15)%, much less than the data of detector A with offsets of (7 +/- 8)% and (16 +/- 7)% for the two lines, respectively, relative to CDS. Finally, the intercalibration measurements after the loss and recovery of the SOHO spacecraft are analyzed. The data for observations from November 1998 to July 2000 are compared, and it is shown that, although the responses of the instruments have changed, the CDS and the SUMER still perform well, and their temporal correlation is good. (C) 2001 Optical Society of America. C1 ETH Zentrum, Inst Astron, CH-8092 Zurich, Switzerland. Hsch Tech & Architektur, Inst Technol Transfer, CH-3000 Bern 22, Switzerland. World Radiat Ctr, Phys Meteorol Observ, CH-7260 Davos, Switzerland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. NASA, Goddard Space Flight Ctr, Emergent Informat Technol Inc, Greenbelt, MD 20771 USA. Phys Tech Bundesanstalt, D-10587 Berlin, Germany. European Space Agcy, European Space Res & Technol Ctr, NL-2200 AG Noordwijk, Netherlands. RP Pauluhn, A (reprint author), Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland. EM pauluhn@issi.unibe.ch RI Thompson, William/D-7376-2012; Solanki, Sami/E-2487-2013; Hollandt, Jorg/A-2124-2014 OI Solanki, Sami/0000-0002-3418-8449; NR 14 TC 14 Z9 14 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 2001 VL 40 IS 34 BP 6292 EP 6300 DI 10.1364/AO.40.006292 PG 9 WC Optics SC Optics GA 501YE UT WOS:000172713000022 PM 18364935 ER PT J AU Garvin, JB Figueroa, O Naderi, FM AF Garvin, James B. Figueroa, Orlando Naderi, Firouz M. TI NASA's New Mars Exploration Program: The Trajectory of Knowledge SO ASTROBIOLOGY LA English DT Article DE Mars Exploration Program; Science Strategy; Mars Sample Return; Mars Global Surveyor; Mars Odyssey AB NASA's newly restructured Mars Exploration Program (MEP) is finally on the way to Mars with the successful April 7 launch of the 2001 Mars Odyssey Orbiter. In addition, the announcement by the Bush Administration that the exploration of Mars will be a priority within NASA's Office of Space Science further cements the first decade of the new millennium as one of the major thrusts to understand the "new" Mars. Over the course of the past year and a half, an integrated team of managers, scientists, and engineers has crafted a revamped MEP to respond to the scientific as well as management and resource challenges associated with deep space exploration of the Red Planet. This article describes the new program from the perspective of its guiding philosophies, major events, and scientific strategy. It is intended to serve as a roadmap to the next 10-15 years of Mars exploration from the NASA viewpoint. [For further details, see the Mars Exploration Program web site (URL): http://mars.jpl.nasa.gov]. The new MEP will certainly evolve in response to discoveries, to successes, and potentially to setbacks as well. However, the design of the restructured strategy is attentive to risks, and a major attempt to instill resiliency in the program has been adopted. Mars beckons, and the next decade of exploration should provide the impetus for a follow-on decade in which multiple sample returns and other major program directions are executed. Ultimately the vision to consider the first human scientific expeditions to the Red Planet will be enabled. By the end of the first decade of this program, we may know where and how to look for the elusive clues associated with a possible martian biological record, if any was every preserved, even if only as "chemical fossils." Key Words: Mars Exploration Program-Science Strategy-Mars Sample Return-Mars Global Surveyor-Mars Odyssey. C1 [Garvin, James B.; Figueroa, Orlando] NASA Headquarters, Mars Explorat Program, Off Space Sci, Washington, DC USA. [Naderi, Firouz M.] NASA, Jet Prop Lab, Mars Program Off, Pasadena, CA USA. RP Garvin, JB (reprint author), Off Space Sci, Mars Explorat Program, Code SE, 300 E St SW, Washington, DC 20546 USA. EM jgarvin@hq.nasa.gov NR 2 TC 9 Z9 9 U1 1 U2 7 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD DEC PY 2001 VL 1 IS 4 BP 439 EP 446 DI 10.1089/153110701753593847 PG 8 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V38SN UT WOS:000209363200002 PM 12448977 ER PT J AU Wdowiak, TJ Gerakines, PA Agresti, DG Clemett, SJ AF Wdowiak, Thomas J. Gerakines, Perry A. Agresti, David G. Clemett, Simon J. TI Technology Considerations Relevant to an Exobiology Surface-Science Approach for Europa SO ASTROBIOLOGY LA English DT Article DE Europa; Instrument methods; In situ science; Exobiology; Astrobiology AB If Europa is to be of primary exobiological interest, namely, as a habitat for extant life, it is obvious that (a) a hydrosphere must prevail beneath the cryosphere for a long time, (b) internal energy sources must be present in a sufficient state of activity, and (c) a reasonable technical means must be available for assessing if indeed life does exist in the hypothesized hydrosphere. This discussion focuses on the last point, namely, technological issues, because the trend of the compounding evidence about Europa indicates that the first two points are likely to be true. First, we present a consideration of time-of-flight mass spectroscopy conducted in situ on the cryosphere surface of Europa during a first landed robotic mission. We assert that this is a reasonable technical means not only for exploring the composition of the cryosphere itself, but also for locating any biomolecular indicators of extant life brought to the surface through cryosphere activity. Secondly, this work also addresses practical issues inherent in any kind of instrumental interrogation of a surface whose properties are governed by radiation chemistry. This includes advocating the construction of a Europan surface simulator to familiarize instrumental system developers with the spacecraft-and instrument-scale conditions under which such an interrogation would take place on Europa. Such a simulator is mandatory in certification of the functional utility of a flight instrument. C1 [Wdowiak, Thomas J.; Gerakines, Perry A.; Agresti, David G.] Univ Alabama Birmingham, Dept Phys, Astro & Solar Syst Phys Program, Birmingham, AL 35294 USA. [Clemett, Simon J.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Wdowiak, TJ (reprint author), Univ Alabama Birmingham, Dept Phys, Astro & Solar Syst Phys Program, 1300 Univ Blvd, Birmingham, AL 35294 USA. EM wdowiak@uab.edu RI Gerakines, Perry/B-9705-2009; OI Gerakines, Perry/0000-0002-9667-5904 FU NASA Exobiology, Planetary Instrumentation Definition and Development Program; National Research Council FX The ideas presented here are drawn from research supported by NASA Exobiology, Planetary Instrumentation Definition and Development Program, and National Research Council grants. NR 30 TC 1 Z9 1 U1 1 U2 4 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD DEC PY 2001 VL 1 IS 4 BP 467 EP 476 DI 10.1089/153110701753593865 PG 10 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V38SN UT WOS:000209363200004 PM 12448979 ER PT J AU Goldin, DS AF Goldin, Daniel S. TI NASA's Legacy of Mars Exploration: The View from the Administrator Tribute SO ASTROBIOLOGY LA English DT Biographical-Item C1 NASA Headquarters, NASA, Washington, DC 20546 USA. RP Goldin, DS (reprint author), NASA Headquarters, NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD DEC PY 2001 VL 1 IS 4 BP 495 EP 499 DI 10.1089/153110701753593900 PG 5 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V38SN UT WOS:000209363200008 PM 12448983 ER PT J AU Garvin, JB AF Garvin, James B. TI The Emerging Face of Mars: A Synthesis from Viking to Mars Global Surveyor Tribute SO ASTROBIOLOGY LA English DT Biographical-Item C1 [Garvin, James B.] NASA Headquarters, Mars Explorat, Washington, DC USA. RP Garvin, JB (reprint author), Off Space Sci, Mars Explorat Program, 300 E St SW, Washington, DC 20546 USA. EM jgarvin@hq.nasa.gov NR 0 TC 2 Z9 2 U1 0 U2 2 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD DEC PY 2001 VL 1 IS 4 BP 513 EP 521 DI 10.1089/153110701753593946 PG 9 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V38SN UT WOS:000209363200012 PM 12448987 ER PT J AU Lockwood, MK AF Lockwood, Mary Kae TI NASA Langley Research Center Tribute SO ASTROBIOLOGY LA English DT Biographical-Item C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lockwood, MK (reprint author), NASA, Langley Res Ctr, Mailstop 365, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD DEC PY 2001 VL 1 IS 4 BP 523 EP 525 DI 10.1089/153110701753593955 PG 3 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA V38SN UT WOS:000209363200013 PM 12448988 ER PT J AU Surace, JA Sanders, DB Evans, AS AF Surace, JA Sanders, DB Evans, AS TI Optical and near-infrared imaging of infrared-excess palomar-green quasars SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; galaxies : active; quasars : general ID RADIO-QUIET QUASARS; CONTINUUM ENERGY-DISTRIBUTIONS; PHOTOMETRIC STANDARD STARS; SPACE-TELESCOPE IMAGES; HOST GALAXIES; LUMINOUS QUASARS; CELESTIAL EQUATOR; LOUD QUASARS; JY SAMPLE; RESOLUTION AB Ground-based high spatial resolution (FWHM < 0."3-0."8) optical and near-infrared imaging (0.4-2.2 km) is presented for a complete sample of optically selected Palomar-Green QSOs with far-infrared excesses at least as great as those of "warm" AGN-like ultraluminous infrared galaxies (L(ir)/L(BBB) > 0.46). In all cases, the host galaxies of the QSOs were detected, and most have discernible two-dimensional structure. The QSO host galaxies and the QSO nuclei are similar in magnitude at H band. H-band luminosities of the hosts range from 0.5-7.5 L*, with a mean of 2.3 L*, and are consistent with those found in ultraluminous infrared galaxies. Both the QSO nuclei and the host galaxies have near-infrared excesses, which may be the result of dust associated with the nucleus and of recent dusty star formation in the host. These results suggest that some, but not all, optically selected QSOs may have evolved from an infrared active state triggered by the merger of two similarly sized L* galaxies, in a manner similar to that of the ultraluminous infrared galaxies. C1 CALTECH, Jet Prop Lab, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. SUNY Stony Brook, Dept Phys Math & Astron, Stony Brook, NY 11794 USA. RP Surace, JA (reprint author), CALTECH, Jet Prop Lab, SIRTF Sci Ctr, MS 220-6, Pasadena, CA 91125 USA. EM jason@ipac.caltech.edu; sanders@ifa.hawaii.edu; sanders@ifa.hawaii.edu NR 62 TC 43 Z9 43 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 2791 EP 2809 DI 10.1086/324462 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200001 ER PT J AU Oegerle, WR Hill, JM AF Oegerle, WR Hill, JM TI Dynamics of cD clusters of galaxies. IV. Conclusion of a survey of 25 Abell clusters SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (A779, A1691, A1749, A1767, A1837, A1927, A2061, A2067, A2079, A2089, A2199, A2666); galaxies : elliptical and lenticular, cD; galaxies : kinematics and dynamics ID X-RAY; MULTIPLE NUCLEI; RICH CLUSTERS; PECULIAR VELOCITIES; REDSHIFT DATA; SUBSTRUCTURE; CONSTRAINTS; CANNIBALISM; EVOLUTION; CATALOG AB We present the final results of a spectroscopic study of a sample of cD galaxy clusters. The goal of this program has been to study the dynamics of the clusters, with emphasis on determining the nature and frequency of cD galaxies with peculiar velocities. Redshifts measured with the MX Spectrometer have been combined with those obtained from the literature to obtain typically 50-150 observed velocities in each of 25 galaxy clusters containing a central cD galaxy. We present a dynamical analysis of the final 11 clusters to be observed in this sample. All 25 clusters are analyzed in a uniform manner to test for the presence of substructure and to determine peculiar velocities and their statistical significance for the central cD galaxy. These peculiar velocities were used to determine whether or not the central cD galaxy is at rest in the cluster potential well. We find that 30%-50% of the clusters in our sample possess significant subclustering (depending on the cluster radius used in the analysis), which is in agreement with other studies of non-cD clusters. Hence, the dynamical state of cD clusters is not different than that of other present-day clusters. After careful study, four of the clusters appear to have a cD galaxy with a significant peculiar velocity. Dressler-Shectman tests indicate that three of these four clusters have statistically significant substructure within 1.5 h(75)(-1) Mpc of the cluster center. The dispersion of the cD peculiar velocities is 164(-34)(+41) km s(-1) around the mean cluster velocity. This represents a significant detection of peculiar cD velocities but at a level that is far below the mean velocity dispersion for this sample of clusters. The picture that emerges is one in which cD galaxies are nearly at rest with respect to the cluster potential well but have small residual velocities due to subcluster mergers. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Oegerle, WR (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Oegerle, William/C-9070-2012 NR 46 TC 97 Z9 101 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 2858 EP 2873 DI 10.1086/323536 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200005 ER PT J AU Jones, DL Preston, RA AF Jones, DL Preston, RA TI Fossil radio emission associated with currently active radio galaxies SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : halos; galaxies : clusters : individual (Cl 1409+524, 1410+5226, A2199); galaxies : evolution; galaxies : individual (1624+416, 1633+382, 1749+701, 3C 295, 3C 338, 3C 345, 3C 371, Mrk 501); radio continuum ID CORE-DOMINATED QUASARS; RANGE VLA OBSERVATIONS; BL LACERTAE OBJECTS; COMPLETE SAMPLE; X-RAY; MILLIARCSECOND STRUCTURE; VLBI OBSERVATIONS; SKY SURVEY; 3C 295; 3C-338 AB We have begun an investigation of how often and for how long galaxies undergo episodes of nonthermal nuclear activity. Radio images of galaxies at high frequencies (similar to1 GHz and above) reveal nuclear activity over only a limited time interval preceding the current epoch. However, extended radio emission from earlier epochs of activity should be more prominent at lower radio frequencies because the much longer synchrotron radiation lifetimes of low-energy electrons result in spectra that steepen with time. After similar to 10(8) yr, radio emission from early epochs of activity may only be detectable at lower radio frequencies. To begin our investigation, we have chosen fields for observation that contain currently active galaxies because these are known to be capable of nuclear activity. We observed three 10 degrees fields with the VLA at 74 MHz that contained seven active galaxies from the Pearson-Readhead sample plus a rich cluster of galaxies. Three of the active galaxies and the galaxy cluster were also observed at 327 MHz. None of the targeted active galaxies showed extended emission that we interpret as evidence of earlier activity. However, 10 background radio sources (out of similar to 100) in the VLA fields of view did appear to have extended low-frequency emission, with the best case for fossil radio lobes being 3C 338. Our results suggest that extended low-frequency radio emission on scales of several arcminutes may be quite common in radio sources detectable with the VLA at 74 MHz. With adequate statistics, the study of fossil lobes can improve our understanding of the number and duration of active epochs, the history of black hole accretion, and galactic evolution. More sensitive, higher resolution, and lower frequency observations with future instruments will greatly enhance this study. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, Mail Code 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 51 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 2940 EP 2953 DI 10.1086/324458 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200011 ER PT J AU Piner, BG Jones, DL Wehrle, AE AF Piner, BG Jones, DL Wehrle, AE TI Orientation and speed of the parsec-scale jet in NGC 4261 (3C 270) SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4261, 3C 270); galaxies : jets; galaxies : nuclei; radio continuum ID SPACE-TELESCOPE IMAGES; ACTIVE GALACTIC NUCLEI; RADIO GALAXIES; RELATIVISTIC JETS; VLBI OBSERVATIONS; ACCRETION DISK; COMPLETE SAMPLE; NGC-4261; SPECTRA; MOTION AB NGC 4261 (3C 270) is an elliptical galaxy containing a 300 pc-scale nuclear disk of gas and dust imaged by the Hubble Space Telescope (HST), around a central supermassive black hole. Previous VLBI observations of NGC 4261 revealed a gap in emission in the radio counterjet, presumably due to free-free absorption in the inner parsec of the accretion disk. Here we present three 8 GHz VLBA observations of NGC 4261 that allow us to monitor the location and depth of the gap and check for motions in the jet and counterjet. The separation between the brightest peak and the gap is stable, with an upper limit to its motion of 0.01c, supporting the interpretation of the gap as absorption by an accretion disk rather than as an intrinsic jet feature. These observations span a time of order that required for orbiting material in the disk to transit the counterjet, so we are able to search for density changes (clumps) in the disk by monitoring the optical depth of the gap. The optical depth of the gap is stable to within 20% over 5 years at tau = 1.1 +/- 0.1, corresponding to an electron density in the disk that is constant to within 10%. We measure an apparent speed in the jet of (0.52 +/- 0.07)c. An apparent speed could not be measured for the counterjet because of a lack of identifiable features. From the apparent jet speed and the jet-to-counterjet brightness ratio, we calculate the viewing angle of the jet to be 63 degrees +/- 3 degrees and its intrinsic speed to be (0.46 +/- 0.02)c. From the inclination and position angles of the parsec-scale radio jet and outer HST disk rotation axis we calculate a difference between the parsec-scale radio jet and outer HST disk rotation axis of 12 degrees +/- 2 degrees. Because of its well-defined HST disk and bright parsec-scale radio jet and counterjet, NGC 4261 is ideal for studying the combined disk-jet system, and this is the first case known to us in which both the inclination and position angles of both the disk and jet have been determined. C1 Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Piner, BG (reprint author), Whittier Coll, Dept Phys & Astron, 13406 E Philadelphia St, Whittier, CA 90608 USA. NR 31 TC 15 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 2954 EP 2960 DI 10.1086/323927 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200012 ER PT J AU Ruiz, JR Crenshaw, DM Kraemer, SB Bower, GA Gull, TR Hutchings, JB Kaiser, ME Weistrop, D AF Ruiz, JR Crenshaw, DM Kraemer, SB Bower, GA Gull, TR Hutchings, JB Kaiser, ME Weistrop, D TI Kinematics of the narrow-line region in the Seyfert 2 galaxy Markarian 3 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (Markarian 3); galaxies : Seyfert ID NUCLEI; SPECTROPOLARIMETRY; NGC-4151 AB We present measurements of radial velocities for the narrow-line region gas in the Seyfert 2 galaxy Mrk 3 out to similar to1 kpc from the nucleus. The observations consist of two data sets, both using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope : (1) an [O III] slitless spectrum with the G430M grating of the inner 3" around the nucleus and (2) a long-slit observation centered on the nucleus (P.A. = 71 degrees) by using the G430L grating and the 52" x 0.1 aperture. Our analysis produces radial velocity maps of the emission-line gas, which indicate trends in the gas motion. These include blueshifts and redshifts on either side of the nucleus, steep velocity rises from systemic up to about +/- 700 km s(-1) taking place in the inner 0."3 (0.08 kpc) both east and west of the nucleus, gradual velocity descents back to near-systemic values from 0."3-1."0, slightly uneven velocity amplitudes on each side of the nucleus, and narrow velocity ranges over the entire observed region. When fitted to kinematic models for the NLR gas, the data clearly favor one in which the gas exists in a partially filled bicone, is accelerated radially away from the nucleus, and is followed by a constant deceleration (possibly due to collision with an ambient medium). This geometry and general kinematic model are in agreement with previous work done on the NLR gas of NGC 1068 and NGC 4151. On scales of hundreds of parsecs, we conclude that radial outflow may be a common feature of Seyfert galaxies. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Ruiz, JR (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 27 TC 47 Z9 47 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 2961 EP 2968 DI 10.1086/323917 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200013 ER PT J AU Catelan, M Bellazzini, M Landsman, WB Ferraro, FR Pecci, FF Galleti, S AF Catelan, M Bellazzini, M Landsman, WB Ferraro, FR Pecci, FF Galleti, S TI Age as the second parameter in NGC 288/NGC 362? II. The horizontal branch revisited SO ASTRONOMICAL JOURNAL LA English DT Article DE color-magnitude diagrams; globular clusters : individual (NGC 288, NGC 362); stars : horizontal-branch; stars : mass loss; stars : Population II ID GALACTIC GLOBULAR-CLUSTERS; 2ND-PARAMETER PHENOMENON; 2ND PARAMETER; MASS-LOSS; STARS; MODELS; GIANT; PHOTOMETRY; MORPHOLOGY; ABUNDANCES AB We revisit the "second-parameter" pair of globular clusters NGC 288/362 on the basis of theoretical models for red giant branch (RGB) and horizontal branch (HB) stars. The results of the most extensive set of RGB/HB simulations computed so far for these clusters are presented for two different metallicities. Using several different analytical mass-loss formulae for RGB stars, we derive relative "HB morphology ages." We compare them with the relative main-sequence turnoff ages derived by application of the "bridge test" in Paper I, where it was found that NGC 288 is 2 +/- 1 Gyr older than NGC 362. We find that adoption of a higher metallicity ([Fe/H] approximate to -1.2), as favored by the Carretta & Gratton metallicity scale, makes age a much more plausible second-parameter candidate for this pair than is the case when a lower metallicity ([Fe/H] approximate to -1.5), closer to the Zinn & West scale, is adopted. However, while the different HB morphology of these two clusters can be reproduced by canonical HB models with [Fe/H] approximate to -1.2 and an age difference of 2 Gyr, this explanation is not without difficulty. In particular, we confirm previous suggestions that canonical models are unable to reproduce the detailed HB morphology of NGC 288 at its red end, for as yet unknown reasons. Finally, we show that the mass dispersion on the HB of NGC 362 is substantially larger than for NGC 288 and suggest that there is a correlation between the mass dispersion on the HB phase and the central density of globular clusters. This is presumably related to the way environmental effects affect RGB mass loss-another major second-parameter candidate. We argue that, if confirmed, this central density-HB mass dispersion correlation will have to be taken into account in order to conclusively determine whether age may be considered the (sole) second parameter of HB morphology for this (and other) second-parameter pair(s). C1 Univ Virginia, Dept Astron, Charlottesville, VA 22901 USA. Osservatorio Astron Bologna, I-40127 Bologna, Italy. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Stn Astron Cagliari, I-09012 Capoterra, Italy. RP Catelan, M (reprint author), Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Av Vicuna Mackenns 4840,6904411 Macul, Santiago, Chile. RI Bellazzini , Michele/O-9373-2015 OI Bellazzini , Michele/0000-0001-8200-810X NR 62 TC 39 Z9 39 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 3171 EP 3182 DI 10.1086/324449 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200025 ER PT J AU Lyke, JE Gehrz, RD Woodward, CE Barlow, MJ Pequignot, D Salama, A Schwarz, GJ Shore, SN Starrfield, S Evans, A Gonzales-Riestra, R Greenhouse, MA Hjellming, RM Humphreys, RM Jones, TJ Krautter, J Morisset, C Ogelman, HB Orio, M Wagner, RM Walton, NA Williams, RE AF Lyke, JE Gehrz, RD Woodward, CE Barlow, MJ Pequignot, D Salama, A Schwarz, GJ Shore, SN Starrfield, S Evans, A Gonzales-Riestra, R Greenhouse, MA Hjellming, RM Humphreys, RM Jones, TJ Krautter, J Morisset, C Ogelman, HB Orio, M Wagner, RM Walton, NA Williams, RE TI Infrared space observatory short wavelength spectrometer observations of V1425 Aquilae (Nova Aquila 1995) SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; novae, cataclysmic variables; stars : individual (Nova Aquila 1995=V1425 Aquilae) ID PHOTOIONIZATION MODEL; V1974 CYGNI; EVOLUTION; TRANSITIONS; ULTRAVIOLET; EMISSION; SHELL AB We present observations of the classical nova V1425 Aquilae (Nova Aquila 1995) with the Infrared Space Observatory's (ISO) Short Wavelength Spectrometer, the Isaac Newton Telescope's Intermediate Dispersion Spectrograph, and the International Ultraviolet Explorer's Short-Wavelength Primary Spectrograph. Analysis of He II (1640 Angstrom) development constrains the white dwarf turnoff to similar to 400 days after outburst. Photoionization modeling of the optical and ISO spectra obtained during the late nebular phase constrains the mass of the ejecta between 2.5-4.2 x 10(-5) M(.). This modeling also suggests C and O in the ejecta were enhanced by a factor of similar to9, and N was enhanced by a factor of similar to 100 with respect to solar, while Ne was only slightly enhanced. Based upon these analyses, we determine that the white dwarf in the V1425 Aql system has a CO composition and is at a distance of 3.0 +/- 0.4 kpc. C1 Univ Minnesota, Sch Phys & Astron, Dept Astron, Minneapolis, MN 55455 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. Observ Paris, F-92195 Meudon, France. ESA, Div Astrophys, ISO Sci Operat Ctr, E-28080 Madrid, Spain. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Indiana Univ S Bend, Dept Phys & Astron, South Bend, IN USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Keele, Dept Phys, Keele ST5 5BG, Staffs, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Landessternwarte Konigstuhl, D-69117 Heidelberg, Germany. Inst Astrophys Marseille, F-13376 Marseille 12, France. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Osserv Astron Torino, I-10025 Pino Torinese, Italy. Univ Arizona, Large Binocular Telescope Observ, Tucson, AZ 85721 USA. Isaac Newton Grp, Santa Cruz De La Palma 38700, Canary Islands, Spain. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Lyke, JE (reprint author), Univ Minnesota, Sch Phys & Astron, Dept Astron, 116 Church St SE, Minneapolis, MN 55455 USA. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 32 TC 11 Z9 11 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 DEC PY 2001 VL 122 IS 6 BP 3305 EP 3312 DI 10.1086/324100 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200034 ER PT J AU Grady, CA Polomski, EF Henning, T Stecklum, B Woodgate, BE Telesco, CM Pina, RK Gull, TR Boggess, A Bowers, CW Bruhweiler, FC Clampin, M Danks, AC Green, RF Heap, SR Hutchings, JB Jenkins, EB Joseph, C Kaiser, ME Kimble, RA Kraemer, S Lindler, D Linsky, JL Maran, SP Moos, HW Plait, P Roesler, F Timothy, JG Weistrop, D AF Grady, CA Polomski, EF Henning, T Stecklum, B Woodgate, BE Telesco, CM Pina, RK Gull, TR Boggess, A Bowers, CW Bruhweiler, FC Clampin, M Danks, AC Green, RF Heap, SR Hutchings, JB Jenkins, EB Joseph, C Kaiser, ME Kimble, RA Kraemer, S Lindler, D Linsky, JL Maran, SP Moos, HW Plait, P Roesler, F Timothy, JG Weistrop, D TI The disk and environment of the Herbig Be star HD 100546 SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems; stars : individual (HD 100546); stars : pre-main-sequence ID TELESCOPE IMAGING SPECTROGRAPH; MODEL SCATTERING ENVELOPES; YOUNG STELLAR OBJECTS; AE/BE STARS; AE STAR; HD-100546; DUST; EMISSION; SPECTRA; PERFORMANCE AB Coronagraphic imaging of the nearest Herbig Be star with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope, Ks (2.15 mum) imaging with ADONIS at the 3.6 m telescope at La Silla, and mid-infrared imaging with OSCIR using the 4 m Blanco Telescope at Cerro Tololo Inter-American Observatory confirm the detection of the disk reported by Pantin et al. and map the disk out to 5" (similar to 515 AU) in the optical and at Ks. While the source is unresolved at 10 and 18 mum, it can be traced to 1."5 at 11.7 mum. We confirm the change in the radial dependence of the disk surface brightness near seen at 1.6 mum by Augereau et al. at Ks. No such break in the power law is seen in the optical. The STIS data reveal spiral dark lane structure, making HD 100546 the third near-zero-age main-sequence Herbig Ae/Be star with structure more than 100 AU from the star. We also optically detect a low surface brightness envelope extending 10" (1000 AU) from the star, in addition to nebulosity, which is probably associated with DC 292.6-7.9. The survival of the envelope through essentially the entire pre-main-sequence lifetime of the star, coupled with the absence of physical companions within 1500 AU of the star, suggests that envelope lifetimes owe more to the star-forming environment than to mass-loss activity from the Herbig Ae/Be star. C1 NASA, Goddard Space Flight Ctr, NOAO, STIS, Greenbelt, MD 20771 USA. Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Inst Astrophys, D-07745 Jena, Germany. Univ Observ, D-07745 Jena, Germany. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Raytheon Polar Serv Co, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Natl Res Council Canada, Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Princeton Univ Observ, Princeton, NJ 08544 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Sigma Res & Engn, Lanham, MD 20706 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sonoma State Univ, Dept Phys & Astron, Rohnert Pk, CA 94928 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Nightsen Inc, Warwick, RI 02886 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Grady, CA (reprint author), NASA, Goddard Space Flight Ctr, NOAO, STIS, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012; Clampin, mark/D-2738-2012; Kimble, Randy/D-5317-2012; heap, sara/E-2237-2012; Jenkins, Edward/P-5684-2014 OI Gull, Theodore/0000-0002-6851-5380; Jenkins, Edward/0000-0003-1892-4423 NR 39 TC 135 Z9 135 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD DEC PY 2001 VL 122 IS 6 BP 3396 EP 3406 DI 10.1086/324447 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 505TT UT WOS:000172932200041 ER PT J AU Smith, IA Tilanus, RPJ Wijers, RAMJ Tanvir, N Vreeswijk, P Rol, E Kouveliotou, C AF Smith, IA Tilanus, RPJ Wijers, RAMJ Tanvir, N Vreeswijk, P Rol, E Kouveliotou, C TI SCUBA sub-millimeter observations of gamma-ray bursters - II. GRB 991208, 991216, 000301C, 000630, 000911, 000926 SO ASTRONOMY & ASTROPHYSICS LA English DT Review DE gamma rays : bursts; radio continuum : general; infrared : general ID OPTICAL AFTERGLOW; GRB 000301C; STAR-FORMATION; RADIO AFTERGLOW; FIREBALL MODEL; HIGH-REDSHIFT; LIGHT CURVES; HOST GALAXY; JET MODEL; EMISSION AB We discuss our ongoing program of Target of Opportunity sub-millimeter observations of gamma-ray bursts (GRBs) using the Sub-millimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). Sub-millimeter observations of the early afterglows are of interest because this is where the emission peaks in some bursts in the days to weeks following the burst. Of increasing interest is to look for underlying quiescent sub-millimeter sources that may be dusty star-forming host galaxies. In this paper, we present observations of GRB 991208, 991216, 000301C, 000630, 000911, and 000926. For all these bursts, any sub-millimeter emission is consistent with coming from the afterglow. This means that we did not conclusively detect quiescent sub-millimeter counterparts to any of the bursts that were studied from 1997 through 2000. The inferred star formation rates (M greater than or equal to5 M(circle dot)) are typically less than or similar to 300 M(circle dot) yr(-1). If GRBs are due to the explosions of high-mass stars, this may indicate that the relatively small population of extremely luminous dusty galaxies does not dominate the total star formation in the universe at early epochs. Instead, the GRBs may be predominantly tracing slightly lower luminosity galaxies. The optical faintness of some host galaxies is unlikely to be explained as due to dust absorption in the host. C1 Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Joint Astron Ctr, Hilo, HI 96720 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Smith, IA (reprint author), Rice Univ, Dept Phys & Astron, MS-108,6100 S Main, Houston, TX 77005 USA. EM ian@spacsun.rice.edu OI Wijers, Ralph/0000-0002-3101-1808 NR 111 TC 21 Z9 21 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 DEC PY 2001 VL 380 IS 1 BP 81 EP 89 DI 10.1051/0004-6361:20011382 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499AQ UT WOS:000172547900015 ER PT J AU Ghosh, KK Swartz, DA Tennant, AF Wu, K AF Ghosh, KK Swartz, DA Tennant, AF Wu, K TI ROSAT/Chandra observations of a bright transient in M 81 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : binaries; X-rays : galaxies; black hole physics; stars : binaries : close; globular clusters : general ID M81; CHANDRA AB We present a 10-year X-ray light curve and the spectra of a peculiar X-ray transient in the spiral galaxy M 81. The source was below the detection limit of ROSAT PSPC before 1993, but it brightened substantially in 1993, with luminosities exceeding the Eddington limit of a 1.5-M(.) compact accretor. It then faded and was not firmly detected in the ROSAT HRI and PSPC observations after 1994. The Chandra image obtained in 2000 May, however, shows an X-ray source at its position within the instrumental uncertainties. The Chandra source is coincident with a star-like object in the Digitized-Sky-Survey. A Hubble image suggests that the optical object may be extended. While these three observations could be of the same object, which may be an X-ray binary containing a black-hole candidate, the possibility that the ROSAT and Chandra sources are two different objects in a dense stellar environment cannot be ruled out. The Hubble data suggests that the optical object may be a globular cluster yet to be identified. C1 NASA, George C Marshall Space Flight Ctr, NRC, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, USRA, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Sydney, Sch Phys A28, Sydney, NSW 2006, Australia. RP Ghosh, KK (reprint author), NASA, George C Marshall Space Flight Ctr, NRC, SD-50, Huntsville, AL 35812 USA. EM kajal.ghosh@msfc.nasa.gov; doug.swartz@msfc.nasa.gov; allyn.tennant@msfc.nasa.gov; kw@mssl.ucl.ac.uk NR 27 TC 4 Z9 4 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 DEC PY 2001 VL 380 IS 1 BP 251 EP 257 DI 10.1051/0004-6361:20011396 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499AQ UT WOS:000172547900034 ER PT J AU Barnard, R Balucinska-Church, M Smale, AP Church, MJ AF Barnard, R Balucinska-Church, M Smale, AP Church, MJ TI A study of the spectral evolution during dipping in XB 1323-619 with Rossi-XTE and BeppoSAX SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : stars; stars : individual : XB1323-619; stars : neutron; binaries : close; accretion : accretion disks; ISM : dust, extinction ID IRON-K LINE; PERIODIC INTENSITY DIPS; INTERSTELLAR GRAINS; RAY BINARIES; EXO 0748-676; DISCOVERY; EMISSION; CATALOG; GINGA; ABSORPTION AB We report results from analysis of the observations of the dipping low mass X-ray binary XB 1323-619 made with BeppoSAX and Rossi-XTE. The dust-scattered halo contributes significantly in this source, and the observation made with BeppoSAX on 1997 August was used to provide MECS radial intensity profiles at several energies. From these, the halo fractions were obtained and thus an optical depth to dust scattering of 1.8 +/- 0.4 derived. In the Rossi-XTE observation of April 25-28, 1997, seven X-rays dips were observed together with 7 bursts repeating approximately periodically. Non-dip and dip PCA spectra can be well-described by assuming the emission consists of point-like blackbody emission identified with the neutron star, plus Comptonized emission from an extended ADC. The blackbody temperature is 1.79 +/- 0.21 keV and the cut-off power law photon index 1.61 +/- 0.04. Spectral evolution in dipping is well described by progressive covering of the extended Comptonizing region by absorber plus more rapid removal of the point-like blackbody. The effects of dust scattering and of the X-ray pulsar 1SAXJ1324.4-6200 also in the field of view are included in the fitting. We detect an iron line at similar to6.4 keV and its probable origin in the ADC is discussed. C1 Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Jagiellonian Univ, Inst Astron, PL-30244 Krakow, Poland. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Church, MJ (reprint author), Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. EM robb@star.sr.bham.ac.uk; mbc@star.sr.bham.ac.uk; alan@osiris.gsfc.nasa.gov; mjc@star.sr.bham.ac.uk NR 42 TC 22 Z9 22 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD DEC PY 2001 VL 380 IS 2 BP 494 EP 503 DI 10.1051/0004-6361:20011363 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 500HH UT WOS:000172620600014 ER PT J AU Pottasch, SR Beintema, DA Salas, JB Feibelman, WA AF Pottasch, SR Beintema, DA Salas, JB Feibelman, WA TI Abundances of planetary nebulae NGC 7662 and NGC 6741 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; planetary nebulae : individual : NGC7662, NGC6741; infrared : ISM : lines and bands ID NGC-7662; SPECTRA; DISTANCES; CATALOG; FLUXES; LINES AB The ISO and IUE spectra of the elliptical nebulae NGC7662 and NGC6741 are presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous determinations. The abundances found are compared to determinations made in other nebulae using ISO data. A discussion is given to see if possible evolutionary effects can be found from the abundance differences. C1 Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. SRON, Lab Space Res, NL-9700 AV Groningen, Netherlands. Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD USA. RP Pottasch, SR (reprint author), Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. EM pottasch@astro.rug.nl NR 31 TC 29 Z9 29 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 DEC PY 2001 VL 380 IS 2 BP 684 EP 694 DI 10.1051/0004-6361:20011480 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 500HH UT WOS:000172620600030 ER PT J AU Zand, JJMI Swank, J Corbet, RHD Markwardt, CB AF Zand, JJMI Swank, J Corbet, RHD Markwardt, CB TI Discovery of a 1247 s pulsar in the Be X-ray binary SAX J2239.3+6116 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : neutron; pulsars : SAX J2239.3+6116; X-rays : binaries ID ACCRETION; ORBIT AB A search for pulsations from the Be X-ray binary SAX J2239.3+6116, through observations with the Narrow Field Instruments on BeppoSAX and the Proportional Counter Array on RXTE, yielded the clear presence of a 1247 s coherent oscillation. Given the fairly high X-ray luminosity on previous occasions (up to a few times 10(36) erg s(-1) in 2 to 28 keV), the oscillation must be due to the spin of a neutron star. Assuming that the 262 day recurrence time is the orbital period, SAX J2239.3+6116 has both the longest orbital period and the longest pulse period of 24 Be X-ray binaries with measured orbital periods. C1 Univ Utrecht, Astron Inst, NL-3508 TA Utrecht, Netherlands. SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Univ Utrecht, Astron Inst, POB 80000, NL-3508 TA Utrecht, Netherlands. EM jeanz@sron.nl RI Swank, Jean/F-2693-2012 NR 20 TC 11 Z9 11 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD DEC PY 2001 VL 380 IS 1 BP L26 EP L29 DI 10.1051/0004-6361:20011512 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499AQ UT WOS:000172547900007 ER PT J AU Williger, G AF Williger, G TI The view from across the pond SO ASTRONOMY & GEOPHYSICS LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Williger, G (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1366-8781 J9 ASTRON GEOPHYS JI Astron. Geophys. PD DEC PY 2001 VL 42 IS 6 BP 9 EP 9 PG 1 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA 499TE UT WOS:000172585800011 ER PT J AU Boroson, B Kallman, T Vrtilek, SD AF Boroson, B Kallman, T Vrtilek, SD TI Hot outflowing gas from the X-ray binary Hercules X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : individual (Hercules X-1, HZ Herculis); ultraviolet : stars; X-rays : binaries; X-rays : individual (Hercules X-1, HZ Herculis) ID TELESCOPE IMAGING SPECTROGRAPH; INFRARED-SPECTROSCOPY; EMISSION-LINES; MASS-TRANSFER; STELLAR WIND; HZ; ACCRETION; RADIATION; EVOLUTION; SYSTEMS AB We present a unified picture of outflowing gas from the X-ray binary system Hercules X-1/HZ Herculis. We suggest that the outflowing gas (a wind) causes UV emission seen in mid-eclipse, narrow UV absorption lines, and broad UV P Cygni lines. Observations with the FOS and STIS spectrographs on the Hubble Space Telescope (HST) show UV emission lines in the middle of X-ray eclipse, when the X-ray-heated atmosphere of the normal star and accretion disk should be entirely hidden from view. Narrow absorption lines (FWHM approximate to 50 km s(-1)) blueshifted by 500 km s(-1) during observations in 1998 and by 400 km s(-1) during observations in 1999 were seen from phi = 0 to 0.3. The line velocity was constant to within 20 km s(-1). The P Cygni profiles from Hercules X-1 have optical depths tau less than or similar to 1 with a maximum expansion velocity of approximate to 600 km s(-1), and are seen in the resonance lines N V lambda lambda 1238.8, 1242.8, Si IV lambda lambda 1393.7, 1402.8, and C IV lambda lambda 1548.2, 1550.8. We discuss whether this wind originates in the accretion disk or on the companion star, and how the relevant ions can survive X-ray ionization by the neutron star. C1 Claremont Coll, Joint Sci Dept, Claremont, CA 91711 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Boroson, B (reprint author), Claremont Coll, Joint Sci Dept, Claremont, CA 91711 USA. NR 40 TC 10 Z9 10 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 925 EP 935 DI 10.1086/323850 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600030 ER PT J AU Corbet, RHD Peele, AG AF Corbet, RHD Peele, AG TI 4U 2206+54: An unusual high-mass X-ray binary with a 9.6 day orbital period but no strong pulsations SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : emission-line, Be; X-rays : binaries; X-rays : stars ID TRANSIENT A0538-66; GAMMA-CASSIOPEIAE; STELLAR WIND; ACCRETION; STARS; 4U-1700-37; SYSTEMS; VARIABILITY; MODULATION; OUTBURST AB Rossi X-Ray Timing Explorer (RXTE) All-Sky Monitor observations of the X-ray source 4U 2206+54, previously proposed to be a Be star system, show the X-ray flux to be modulated with a period of approximately 9.6 days. If the modulation is due to orbital variability, then this would be one of the shortest orbital periods known for a Be star X-ray source. However, the X-ray luminosity is relatively modest, whereas a high luminosity would be predicted if the system contains a neutron star accreting from the denser inner regions of a Be star envelope. Although a 392 s pulse period was previously reported from EXOSAT observations, a reexamination of the EXOSAT light curves does not show this or any other periodicity. An analysis of archival RXTE Proportional Counter Array observations also fails to show any X-ray pulsations. We consider possible models that may explain the properties of this source, including a neutron star with accretion halted at the magnetosphere and an accreting white dwarf. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Melbourne, Sch Phys, Parkville, Vic 3010, Australia. RP Corbet, RHD (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. NR 40 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 936 EP 942 DI 10.1086/323849 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600031 ER PT J AU Smale, AP AF Smale, AP TI A second intense burst with photospheric radius expansion from X2127+119 in M15 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (X2127+119); stars : neutron; X-rays : bursts; X-rays : stars ID X-RAY BURST; GLOBULAR-CLUSTER M15; NEUTRON-STARS; SPECTRA; LUMINOSITY; GIANTS; PERIOD AB In 2000 September we observed a bright X-ray burst from X2127+119 with the Rossi X-Ray Timing Explorer. This burst has a multipeaked profile, a peak luminosity of similar to6.5 x 10(38) ergs s(-1), a total integrated energy of similar to2 x 10(40) ergs, and significant photospheric radius expansion to a maximum extent of R = 118 +/- 5 km. From the luminosity-temperature relation during the expansion phase we derive estimates for the gravitational redshift at the neutron star surface, the corrected Eddington luminosity, and the neutron star mass. We detect no slow (similar to 30 s) radial oscillations, fast (100-1200 Hz) coherent oscillations, or quasi-periodic oscillations during the burst. The 2000 September event is only the second burst ever observed from this globular cluster binary (in M15 = NGC 7078), and it shares many characteristics with the event detected by Ginga in 1988 October, the key difference probably being the total amount of material consumed in the thermonuclear flash. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Smale, AP (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. NR 31 TC 18 Z9 18 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 957 EP 962 DI 10.1086/323517 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600034 ER PT J AU Froning, CS Long, KS Drew, JE Knigge, C Proga, D AF Froning, CS Long, KS Drew, JE Knigge, C Proga, D TI Fuse observations of U geminorum during outburst and decline SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; novae, cataclysmic variables; stars : individual (U Geminorum); ultraviolet : stars ID HOPKINS-ULTRAVIOLET-TELESCOPE; LOCAL INTERSTELLAR-MEDIUM; ACCRETION DISK WINDS; VARIABLE IX-VELORUM; 3 DWARF NOVAE; WHITE-DWARF; CATACLYSMIC VARIABLES; SS-CYGNI; IUE OBSERVATIONS; ASTROMETRIC PARALLAXES AB We have obtained far-ultraviolet (904-1187 Angstrom) spectra of U Gem in outburst with the Far Ultraviolet Spectroscopic Explorer. Three of the observations were acquired during the plateau phase of the outburst, while the fourth was obtained during late outburst decline. The plateau spectra have continuum shapes and fluxes that are approximated by steady state accretion disk model spectra with (m) over dot similar or equal to 7 x 10(-9) M. yr(-1). The spectra also show numerous absorption lines of H I, He II, and 2-5 times ionized transitions of C, N, O, P, S, and Si. There are no emission features in the spectra, with the possible exception of a weak feature on the red wing of the O VI doublet. The absorption lines are narrow (FWHM similar to 500 km s(-1)), too narrow to arise from the disk photosphere, and at low velocities (less than or equal to 1700 km s(-1)). The S VI and O VI doublets are optically thick. The absorption lines in the plateau spectra show orbital variability : in spectra obtained at orbital phases 0.53 less than or equal to Phi less than or equal to 0.79, low-ionization absorption lines appear and the central depths of the preexisting lines increase. The increase in line absorption occurs at the same orbital phases as previously observed EUV and X-ray light-curve dips. If the absorbing material is in (near-) Keplerian rotation around the disk, it must be located at large disk radii. The final observation occurred when U Gem was about 2 mag from optical quiescence. The spectra are dominated by emission from an similar or equal to 43,000 K, metal-enriched white dwarf (WD). The inferred radius of the WD is 4.95 x 10(8) cm, close to that observed in quiescence. Allowing for a hot heated region on the surface of the WD improves the fit to the spectrum at short (less than 960 Angstrom) wavelengths. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Froning, CS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. OI Drew, Janet/0000-0003-1192-7082 NR 74 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 963 EP 984 DI 10.1086/323860 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600035 ER PT J AU Corcoran, MF Swank, JH Petre, R Ishibashi, K Davidson, K Townsley, L Smith, R White, S Viotti, R Damineli, A AF Corcoran, MF Swank, JH Petre, R Ishibashi, K Davidson, K Townsley, L Smith, R White, S Viotti, R Damineli, A TI The Chandra HETGS X-ray grating spectrum of eta Carinae SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; stars : early-type; stars : individual (eta Carinae); X-rays : stars ID EMISSION; NEBULA; BINARY; RATIO AB eta Carinae may be the most massive and luminous star in the Galaxy and is suspected to be a massive colliding-wind binary system. The Chandra X-ray observatory has obtained a calibrated high-resolution X-ray spectrum of the star, uncontaminated by the nearby extended soft X-ray emission. Our 89 ks Chandra observation with the High-Energy Transmission Grating Spectrometer (HETGS) shows that the hot gas near the star is nonisothermal. The temperature distribution may represent the emission on either side of the colliding-wind bow shock, effectively "resolving" the shock. If so, the preshock wind velocities are similar to 700 and similar to 1800 km s(-1) in our analysis, and these velocities may be interpreted as the terminal velocities of the winds from eta Carinae and from the hidden companion star. The forbidden-to-intercombination ( f/i) line ratios for the He-like ions of S, Si, and Fe are large, indicating that the line-forming region lies far from the stellar photosphere. The iron fluorescent line at 1.93 Angstrom first detected by ASCA, is clearly resolved from the thermal iron line in the Chandra grating spectrum. The Fe fluorescent line is weaker in our Chandra observation than in any of the ASCA spectra. The Chandra observation also provides an uninterrupted, high time resolution light curve of the stellar X-ray emission from eta Carinae and suggests that there was no significant coherent variability during the Chandra observation. The eta Carinae Chandra grating spectrum is unlike recently published X-ray grating spectra of single massive stars in significant ways and is generally consistent with colliding-wind emission in a massive binary. C1 Univ Space Res Assoc, Seabrook, MD 20706 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Natl Res Council, Lab Astron & Space Phys, Greenbelt, MD 20771 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CNR, Ist Astrofis Spaziale, Area Ric Tor Vergata, I-00133 Rome, Italy. Univ Sao Paulo, Inst Astron & Geofis, BR-04301904 Sao Paulo, Brazil. RP Corcoran, MF (reprint author), Univ Space Res Assoc, 7501 Forbes Blvd,Suite 206, Seabrook, MD 20706 USA. RI Damineli, Augusto/D-8210-2012; Swank, Jean/F-2693-2012 OI Damineli, Augusto/0000-0002-7978-2994; NR 30 TC 31 Z9 31 U1 2 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 1031 EP 1037 DI 10.1086/323322 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600040 ER PT J AU Krall, J Chen, J Duffin, RT Howard, RA Thompson, BJ AF Krall, J Chen, J Duffin, RT Howard, RA Thompson, BJ TI Erupting solar magnetic flux ropes: Theory and observation SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : coronal mass ejections (CMEs); Sun : magnetic fields; Sun : prominences ID CORONAL MASS EJECTIONS; GEOMAGNETIC STORMS; ACTIVE REGIONS; CLOUDS; MODEL; LASCO; EVOLUTION; FLARES; PLASMA; EIT AB Measurements of coronograph (LASCO) and extreme-ultraviolet (EIT) images are presented for 11 coronal mass ejection (CME) events. Detailed measurements of these events, selected because they have flux-rope-like morphological features, show excellent agreement with results from a theoretical model of erupting flux-rope dynamics. Here, data are used to provide inputs and constraints on the model wherever possible. We conclude that flux rope CMEs constitute a distinct class of CMEs, characterized by specific morphological and dynamical properties. C1 USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krall, J (reprint author), USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. RI Thompson, Barbara/C-9429-2012 NR 55 TC 63 Z9 63 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP 1045 EP 1057 DI 10.1086/323844 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LL UT WOS:000172572600042 ER PT J AU Benlloch, S Wilms, J Edelson, R Yaqoob, T Staubert, R AF Benlloch, S Wilms, J Edelson, R Yaqoob, T Staubert, R TI Quasi-periodic oscillation in Seyfert galaxies: Significance levels. The case of Markarian 766 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : individual (Markarian 766) -; galaxies : Seyfert; X rays : galaxies ID X-RAY VARIABILITY; XMM-NEWTON; PN-CCD; NGC-6814; EMISSION; SPECTRUM; EXOSAT AB We discuss methods to compute significance levels for the existence of quasi-periodic oscillations (QPOs) in active galactic nuclei (AGNs) that take the red-noise character of the X-ray light curves of these objects into account. Applying epoch folding and periodogram analysis to the XMM-Newton observation of the Seyfert galaxy Mrk 766, a possible QPO at a timescale of 4200 s has been reported. Our computation of the significance of this QPO, however, shows that the 4200 s peak is not significant at the 95% level. We conclude that the 4200 s feature is an artifact of the red-noise process and not the result of a physical process within the AGNs. C1 Univ Tubingen, Inst Astron & Astrophys Astron, D-72076 Tubingen, Germany. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Benlloch, S (reprint author), Univ Tubingen, Inst Astron & Astrophys Astron, Waldhauser Str 64, D-72076 Tubingen, Germany. EM benlloch@astro.uni-tuebingen.de RI Wilms, Joern/C-8116-2013 OI Wilms, Joern/0000-0003-2065-5410 NR 30 TC 37 Z9 37 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2001 VL 562 IS 2 BP L121 EP L124 DI 10.1086/338252 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 499LM UT WOS:000172572700003 ER PT J AU Aptekar, RL Frederiks, DD Golenetskii, SC Il'inskii, VN Mazets, EP Pal'shin, VD Butterworth, PS Cline, TL AF Aptekar, RL Frederiks, DD Golenetskii, SC Il'inskii, VN Mazets, EP Pal'shin, VD Butterworth, PS Cline, TL TI Konus catalog of soft gamma repeater activity: 1978 to 2000 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE gamma rays : bursts; gamma rays : observations; supernova remnants ID MAGNETIZED NEUTRON-STARS; HIGH-ENERGY TRANSIENT; X-RAY COUNTERPART; SGR 1900+14; STATISTICAL PROPERTIES; WIND OBSERVATIONS; RECURRENT BURSTS; SGR-1900+14; SGR1806-20; DISCOVERY AB Observational data on the bursting activity of all five known soft gamma repeaters (SGRs) are presented. This information was obtained with Konus gamma-ray burst experiments on board Venera 11-14, Wind, and Kosmos 2326 in the period from 1978 to 2000. These data on rates, time histories, and energy spectra of repeated soft bursts, obtained with similar instruments and collected together in a comparable form, should be useful for further studies of SGRs. C1 Russian Acad Sci, AF Ioffe Physicotech Inst, St Petersburg 194021, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Aptekar, RL (reprint author), Russian Acad Sci, AF Ioffe Physicotech Inst, St Petersburg 194021, Russia. RI Frederiks, Dmitry/C-7612-2014; Pal'shin, Valentin/F-3973-2014; Aptekar, Raphail/B-3456-2015; Golenetskii, Sergey/B-3818-2015; OI Frederiks, Dmitry/0000-0002-1153-6340 NR 53 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD DEC PY 2001 VL 137 IS 2 BP 227 EP 277 DI 10.1086/322530 PG 51 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 500KL UT WOS:000172626300001 ER PT J AU Potter, CS Alexander, SE Coughlan, JC Klooster, SA AF Potter, CS Alexander, SE Coughlan, JC Klooster, SA TI Modeling biogenic emissions of isoprene: exploration of model drivers, climate control algorithms, and use of global satellite observations SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE isoprene; biogenic emissions; remote sensing; ecosystem modeling; emission factors ID NET PRIMARY PRODUCTION; NDVI DATA SET; TEMPORAL VARIABILITY; ECOSYSTEM PRODUCTION; SOLAR-RADIATION; FOREST CANOPY; OAK LEAVES; PHOTOSYNTHESIS; SURFACE; VEGETATION AB An improved global budget for isoprene emissions from terrestrial vegetation sources is fundamental to a better understanding of the oxidative capacity of the lower atmosphere and changes in the concentration of major greenhouse gases. In this study,,ve present a biosphere modeling analysis designed to ascertain the interactions of global data drivers for estimating biogenic isoprene emissions. We have integrated generalized isoprene emission algorithms into a process-based simulation model of ecosystem carbon fluxes, the NASA-CASA (Carnegie-Ames-Stanford Approach) model. This new modeling approach for predicting isoprene emissions operates on scales designed to directly link regional and global satellite data sets with estimates of ecosystem carbon cycling, hydrology, and related biogeochemistry. The NASA-CASA model results indicate that the annual isoprene flux from terrestrial plant sources is 559 Tg C. Three ecosystem types, broadleaf evergreen forest, dry tropical forest, and wooded grassland (savanna), account for approximately 80% of these global vegetation isoprene emissions. Based on analyses to improve understanding of the relative influence of climatic (e.g., light and temperature) versus biotic (NPP) controllers on predicted isoprene emission estimates, it appears that the largest portion of total biogenic flux to the global atmosphere is emitted from ecosystems that are mainly light-limited for isoprene emissions, These modeling results imply that, along with better process understanding of base emission factor controls for volatile organic compounds, improvements in global fields of solar surface radiation fluxes in warm climate zones will be needed to reduce major uncertainties in isoprene source fluxes. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Seaside, CA 93955 USA. RP Potter, CS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 46 TC 27 Z9 31 U1 1 U2 14 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. PD DEC PY 2001 VL 35 IS 35 BP 6151 EP 6165 DI 10.1016/S1352-2310(01)00390-9 PG 15 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 506EZ UT WOS:000172958000008 ER PT J AU Roy, RR Ishihara, A Moran, MM Wade, CE Edgerton, VR AF Roy, RR Ishihara, A Moran, MM Wade, CE Edgerton, VR TI No effect of hypergravity on adult rat ventral horn neuron size or SDH activity SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE hypergravity; ventral horn neurons; skeletal muscle; rat ID OXIDATIVE ENZYME-ACTIVITY; SUCCINATE-DEHYDROGENASE ACTIVITY; HINDLIMB SUSPENSION; ALPHA-MOTONEURONS; MUSCLE-FIBERS; SPINAL-CORD; SOMA SIZE; SPACEFLIGHT; SOLEUS; MICROGRAVITY AB Background; Spaceflights of short duration (similar to2 wk) result in adaptations in the size and/or metabolic properties of a select population of motoneurons located in the lumbosacral region of the rat spinal cord. A decrease in succinate dehydrogenase (SDH, an oxidative marker enzyme) activity of moderately sized (500-800 mum(2)) motoneurons in the retrodorsolateral region of the spinal cord (L-6) has been observed after a 14-d flight. Hypothesis. Our hypothesis was that exposure to short-term hypergravity would result in adaptations in the opposite direction, reflecting a continuum of morphological and biochemical responses in the spinal motoneurons from zero gravity to hypergravity. Methods. Young, male rats were centrifuged at either 1.5 or 2.0 G for 2 wk. The size and SDH activity of a population of motoneurons in the retrodorsolateral region of the spinal cord (L-5,) were determined and compared with age-matched rats maintained at 1.0 G. The absolute and relative (to body weight) masses of the soleus, gastrocnemius, adductor longus and tibialis anterior muscles were compared among the three groups. Results: There were no effects of either hypergravity intervention on the motoneuron properties. Rats maintained under hypergravity conditions gained less body mass than rats kept at 1.0 G. For the 1.5 and 2.0 G groups, the muscle absolute mass was smaller and relative mass similar to that observed in the 1.0 G rats, except for the adductor longus. The adductor longus absolute mass was similar to and the relative mass larger in both hypergravity groups than in the 1.0 G group. Conclusions. Our hypothesis was rejected. The findings suggest that rat motoneurons are more responsive to short-term chronic exposure to spaceflight than to hypergravity conditions. C1 Univ Calif Los Angeles, Brain Res Inst, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Physiol Sci, Los Angeles, CA 90095 USA. Kyoto Univ, Fac Integrated Human Studies, Neurochem Lab, Kyoto, Japan. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Roy, RR (reprint author), Univ Calif Los Angeles, Brain Res Inst, Box 951761,1320 Gonda Neurosci & Genet Bldg, Los Angeles, CA 90095 USA. NR 27 TC 3 Z9 3 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD DEC PY 2001 VL 72 IS 12 BP 1107 EP 1112 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 498BV UT WOS:000172490700007 PM 11763112 ER PT J AU Buckey, JC Musiek, FE Kline-Schoder, R Clark, JC Hart, S Havelka, J AF Buckey, JC Musiek, FE Kline-Schoder, R Clark, JC Hart, S Havelka, J TI Hearing loss in space SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Review DE spaceflight; noise-induced hearing loss; occupational noise; audiometry AB Background. Temporary and, in some cases, permanent hearing loss has been documented after long-duration spaceflights. Methods. We examined all existing published data on hearing loss after space missions to characterize the losses. Results. Data from Russian missions suggest that the hearing loss, when it occurs, affects mainly mid to high frequencies and that using hearing protection often might prevent the loss. Several significant questions remain about hearing loss in space. While the hearing loss has been presumed to be noise-induced, no clear link has been established between noise exposure and hearing loss during spaceflight. In one documented case of temporary hearing loss from the Shuttle-Mir program, the pattern of loss was atypical for a noise-induced loss. Continuous noise levels that have been measured on the Mir and previous space stations, while above engineering standards, are not at levels usually associated with hearing loss in ground-based studies (which have usually been limited to 8-10 h exposure periods). Attempts to measure hearing in space using threshold-based audiograms have been unsuccessful in both the American and Russian programs due to noise interference with the measurements. Conclusions: The existing data highlight the need for reliable monitoring of both hearing and noise in long-duration spaceflight. C1 Dartmouth Coll Sch Med, Dept Med, Lebanon, NH USA. Dartmouth Coll Sch Med, Dept Surg Audiol, Lebanon, NH USA. Creare Res & Dev Inc, Hanover, NH 03755 USA. NASA, Lyndon B Johnson Space Ctr, Flight Surg Off, Houston, TX 77058 USA. Life Sci Data Arch, Houston, TX USA. RP Buckey, JC (reprint author), Dartmouth Hitchcock Med Ctr, Dept Med, 1 Med Ctr Dr, Lebanon, NH 03756 USA. NR 11 TC 1 Z9 2 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD DEC PY 2001 VL 72 IS 12 BP 1121 EP 1124 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 498BV UT WOS:000172490700009 PM 11763114 ER EF