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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Figueroa, Fernando Holland, Randy Schmalzel, John Duncavage, Dan Crocker, Alan Alena, Rick NASA Stennis Space Center Stennis Space Center MS 39529 Rowan University Dept. of Electrical and Computer Engineering Glassboro NJ 08028 NASA Johnson Space Center Houston TX 77058 NASA Ames Research Center Moffett Field CA 94035 Science and Technology Division EA41 Stennis Space Center MS 39529 AIAA Department of Electrical and Computer Engineering Rowan University Glassboro NJ 08028 International Space Station Program OD NASA Johnson Space Center Houston TX 77058 Systems Division Mission Operations Directorate DF NASA Johnson Space Center Houston TX 77058 Intelligent Systems Division MS 269-4 Moffett Field CA 94035

ISBN: (纸本)1563478188

This paper addresses methodic implementation of a credible ISHM capability for elements of Constellation systems. ISHM capability must be implemented by a combination of on-board and ground elements, each contributing to determining the health of systems in the most effective manner. Implementation of ISHM capability must evolve continuously to reach higher and higher levels of functional capability. The implication is that a sustainable approach must be defined in order to accomplish a believable capability. This paper describes the methodology, the elements, and the technology to implement ISHM capability throughout the life cycle of elements of Constellation systems, reaching beyond individual elements that might have a limited life while the constellation moves on.

关键词： Spacecraft propulsion

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Effects of Adaptive Cruise Control and Alert Modality on Driver Performance

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Transportation research Record 2006年第1期1980卷 49 - 56页

作者： John D. Lee Daniel V. McGehee Timothy L. Brown Dawn Marshall Cognitive Systems Laboratory Department of Mechanical and Industrial Engineering 2130 Seamans Center Human Factors and Vehicle Safety Research Program Public Policy Center 227 South Quad Human Factors Laboratory National Advanced Driving Simulator and Simulation Center University of Iowa 2401 Oakdale Boulevard Iowa City IA 52242.

Adaptive cruise control (ACC) is a rapidly emerging in-vehicle technology that can enhance or degrade driving safety. A critical factor governing the safety benefit of ACC concerns the driver's ability to assume control of the vehicle in situations that exceed ACC capabilities. The effectiveness of various warning modalities for reengaging distracted drivers during severe braking situations that exceed ACC capability was examined. Warnings that paired a visual icon with sound, seat vibration, or brake pulsation or that combined all three cues were compared. A total of 60 participants drove for 35 min in the National Advanced Driving Simulator. Drivers experienced two severe, four moderate, and eight mild braking situations. ACC could accommodate all but the two severe situations without driver intervention. It also provided a substantial benefit during mild events of lead vehicle braking, enabling drivers to maintain a longer, more consistent minimum time to collision. Unlike performance in previous studies, ACC did not decrease safety during severe braking situations. The combination of a visual icon with sound, seat vibration, or brake pulsation led to slower brake reaction time in severe braking situations, but the grouping of all four warning strategies led to a similar minimum time to collision and maximum braking. In contrast to several previous studies, these results suggest that drivers can effectively assume control when warned that ACC braking authority has been exceeded. Additional research is needed to identify the boundary conditions that specify when drivers can successfully intervene and retake control and whether a multimodal combination of cues can be crafted to speed rather than slow driver response.

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Ultrafast optical switching of photonic crystals

Ultrafast optical switching of photonic crystals

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Conference on Lasers and Electro-Optics (CLEO)

作者： T.G. Euser M. Guina S. Suomalainen J. Kalkman A. Polman Y. Jun H. Wei D.J. Norris W.L. Vos FOM-Institute of Atomic and Molecular Physics (AMOLF) Amsterdam Netherlands Complex Photonic Systems group (COPS) Department of Science and Technology & MESA Research Institute University of Twente Enschede Netherlands Optoelectronics Research Centre ORC Taiyuan University of Science and Technology Tampere Finland Department of Chemical Engineering & Materials Science University of Minnesota Minneapolis MN USA

We present time-resolved reflectivity spectra of optically, homogeneously switched photonic crystals. We observe large, ultrafast shifts of stopbands of GaAs/AlAs multilayer structures as well as in the photonic bandg... 详细信息

ISBN: (纸本)1557528136

关键词： Optical switches Switches Photonic crystals Absorption Gallium arsenide Silicon Reflectivity

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Topology Maintenance of Wireless Sensor Networks in Node Failure-prone Environments

Topology Maintenance of Wireless Sensor Networks in Node Fai...

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IEEE International Conference on Networking, Sensing and Control

作者： L. Frye Liang Cheng Shenfu Du M.W. Bigrigg Department of Computer Science Kutztown University Kutztown PA USA Laboratory of Networking Group (LONGLAB) Department of Computer Science and Engineering Lehigh University Bethlehem PA USA Visiting Research Scholar in LONGLaboratory Lehigh University USA Institute for Complex Engineered Systems Carnegie Mellon University Pittsburgh PA USA

A critical issue in wireless sensor networks is topology management, and maintaining connectivity throughout the network and having a sufficient network lifetime in particular. There have been many topology management schemes proposed. Most of them conserve energy by periodically putting nodes to sleep. One consideration often overlooked is the fact that sensor nodes fail, especially in harsh environments. In this paper, a modification to an existing topology management scheme, Naps, is proposed to ensure very minimal data loss while also handling node failures. The idea is to conserve energy to prolong the lifetime of the nodes and the sensor network while maintaining a constantly connected sensor network. Simulation results demonstrate that failed nodes do not have a significant impact on network connectivity or lifetime, at least in a random, uniform deployment. The paper also illustrates that two different approaches taken in the Naps modification for compensating for failed nodes produce similar results

关键词： Network topology Wireless sensor networks Intelligent networks Sleep Condition monitoring Relays Batteries Terrorism Military communication Degradation

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Urban wet-weather flows

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Water Environment research 2006年第10期78卷 1133-1192页

作者： Clark, Shirley E. Burian, Steven Pitt, Robert Field, Richard Department of Environmental Engineering School of Science Engineering and Technology Penn State Harrisburg 777 W. Harrisburg Pike TL-173 Middletown PA 17057 United States Department of Civil and Environmental Engineering University of Utah Department of Civil and Environmental Engineering University of Alabama Cudworth Professor of Urban Water Systems U.S. EPA Wet-Weather Flow Program Water Supply and Water Resources Division National Risk Management Research Laboratory - Cincinnati

This subject, Urban Wet-Weather Flows, is comprised of three basic subareas - combined-sewer overflows (CSOs), sanitary-sewer overflows (SSOs), and stormwater discharges. Major proceedings related to wet-weather flow (WWF) published during 2005 were the following: (1) WEFTEC 2005, 78th Annual Conference and Exposition (WEF, 2005);(2) Effective Modeling of Urban Stormwater systems, Monograph 13 (CHI, 2005);and (3) 2005 Watershed Management Conference - Managing Watersheds for Human and Natural Impacts (EWRI, 2005). In addition to the conferences listed above, the 2005 Annual Conference of the American Water Resources Association, EWRI's World Environment and Water Resources Congress the 10thInternational Conference on Urban Drainage had significant sessions on wet-weather flows. In addition, many regional conferences also had significant sessions on wet-weather flow issues, such as the 2005 Pennsylvania Stormwater Management Symposium. For all of these, no indexed paper proceedings had been indexed at the time that this literature review was prepared. Copyright © 2006 Water Environment Federation.

关键词： Flow of water

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VDP-A mentor-focused middle school outreach program

VDP-A mentor-focused middle school outreach program

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113th Annual ASEE Conference and Exposition, 2006

作者： Brown, Eugene Kavetsky, Robert Stiegler, Robert L. Squire, Peter N. Matkins, Juanita Jo Hardinge, Gail McLaughlin, John A. Virginia Tech. United States Department of Mechanical Engineering Virginia Tech. United States ONR United States N-STAR Program Catholic University NSWCDD United States USMC Targeting and Engagement Systems Office of Naval Research N-STAR Initiative United States United States George Mason University United States College of William and Mary United States Department of Science Education College of William and Mary United States William and Mary VDP Project United States McLauglin Associates

The Virginia Demonstration Project (VDP) is a science and math outreach program for 7th and 8th grade students. The VDP is funded by the Office of Naval research and is currently being piloted in the middle schools of Stafford, Spotsylvania, and King George County, Virginia. Scientists and engineers employed at the nearby Naval Surface Warfare Center in Dahlgren, Virginia, work alongside the teachers, and, serving as mentors and role models, use problembased learning techniques to give a real-world, Navy-flavored realism to the educational experience. The objective of the program is to increase interest among the students in pursuing careers in math, science, and engineering. © American Society for engineering Education, 2006.

关键词： engineering education

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Chitosan for Biofunctionalization of Microsystems

Chitosan for Biofunctionalization of Microsystems

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IEEE/NLM Life Science systems and Applications Workshop

作者： Stephan T. Koev Michael A. Powers Vlad Badilita Hyunmin Yi William E. Bentley Gregory F. Payne Gary W. Rubloff Reza Ghodssi Institute for Systems Research ISR University of Maryland College Park MD USA University System of Maryland Adelphi MD US Department of Materials Science and Engineering University of Maryland College Park MD USA Department of Chemical Engineering University of Maryland College Park MD 20742 University of Maryland Biotechnology Institute (UMBI) University of Maryland College Park MD 20742 Bioengineering Graduate Program University of Maryland College Park MD 20742 University of Maryland College Park MD USA University of Maryland Biotechnology Institute College Park MD USA Institute for Systems Research (ISR) University of Maryland College Park MD 20742 Department of Materials Science and Engineering University of Maryland College Park MD 20742 Department of Electrical and Computer Engineering University of Maryland College Park MD 20742 Institute for Systems Research (ISR) University of Maryland College Park MD 20742

ISBN: (纸本)1424402778

We present the use of the polysaccharide chitosan for immobilizing biomolecules on microfabricated device surfaces. The main advantages of chitosan are its abundance of primary amine groups and its ability to be electrodeposited. Biomolecules are easily attached to chitosan 's amines by standard glutaraldehyde chemistry. The electrodeposition of chitosan allows accurate spatial and temporal control of biomolecule placement. We have demonstrated this biofunctionalization method for two different bioMEMS devices: a biophotonic sensor and a micromechanical biosensor. We have successfully assembled probe DNA on each of them and detected hybridization with target DNA as a demonstration of sensor operation. Here, we briefly present the fabrication procedure and testing results for both of these bioMEMS sensing devices

关键词： DNA Biosensors Molecular biophysics Probes Micromechanical devices Optical sensors Optical surface waves Optical interferometry Assembly Biomedical optical imaging

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Intrinsic Speed-Sensorless Control of Induction Motor

Intrinsic Speed-Sensorless Control of Induction Motor

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IEEE Conference on Decision and Control

作者： Marcello Montanari Sergei Peresada Andrea Tilli Center for Research on Complex Automated Systems E2809CG. EvangelistiE2809D (CASY) Department of Electronics Computer and System Sciences (DEIS) University of Bologna Bologna Italy Department of Electrical Engineering Ukraine E2809CKiev Polytechnic InstituteE2809D National Technical University Kiev Ukraine

ISBN: (纸本)1424401704

A novel speed sensorless control technique for induction motors is presented. No "simplifying" assumption on the magnetic flux (such as known initial conditions, measurable rotor/stator fluxes) is considered and the load torque is assumed constant, but unknown, according to the usual industrial control problem. In the proposed solution, the natural stabilizing feedback between torque current and the mechanical dynamics is suitably "modulated" using adaptive control techniques. Main feature and novelty of the presented approach is that no explicit speed estimation is utilized to compensate for the load torque (in this sense, the solution is "intrinsic"). Local exponential stability of the resulting nonlinear time-varying tracking error dynamics is guaranteed, if a physically meaningful persistency of excitation condition is satisfied. Simulations results under significant operating conditions are provided

关键词： Induction motors Sensorless control Magnetic flux Torque measurement Rotors Stators Industrial control Feedback Adaptive control Stability

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Numerical simulation of unsteady cavitating flow in a turbopump inducer

Numerical simulation of unsteady cavitating flow in a turbop...

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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Ugajin, Hiroki Kawai, Masafumi Okita, Kohei Matsumoto, Yoichiro Kajishima, Takeo Kawasaki, Satoshi Tomaru, Hiroshi Ishikawajima-Harima Heavy Industries Co. Ltd. Yokohama 235-8501 Japan University of Tokyo Tokyo 113-8656 Japan Osaka University Osaka 565-0871 Japan Ishikawajima-Harima Heavy Industries Co. Ltd. Tokyo 190-1297 Japan Turbomachinery Dpt. Products Development Center 1 Shin-Nakaharacho Isogo-ku AIAA Fluid Group Research Laboratory 21St COE Program Mechanical Systems Innovation RIKEN Department of Mechanical Engineering Space Technology Group Aero-Engine and Space Operations

ISBN: (纸本)1563478188

The unsteady cavitating flow in a turbopump inducer has been calculated using an accurate three-dimensional detached eddy simulation (DES) code, which took into account the cavitating phenomena. The three-dimensional code is based on the numerical method for compressible flow using low Mach number flow approximation. The cavitation is modeled by the source/sink of vapor phase in the liquid flow. The computational results were compared with experimental measurements: circumferentially averaged flow distributions at the inducer exit and visualizations. Qualitative good agreements with experiments were obtained. The unsteady motions of cavities have been simulated in the inducer. The magnitude of the fluctuation in cavity volume increased as the cavities extend and close to the throat of the blade passage. The effect of the tip-gap on the cavity volume was shown;the time-averaged volume of cavities for the inducer with the tip-gap is about five times larger than that for the inducer without the tip-gap at an operating condition. Vorticity generation in cavities due to baroclinic torque was found. This is a feature of cavitating flow. Multiple blade passages calculations are under way to find unsteady phenomena such as rotating cavitation and cavitation surge in the inducer.

关键词： Cavitation

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Mechanical properties of ZrW2O8 filled polymers

Mechanical properties of ZrW2O8 filled polymers

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47th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

作者： Kroetch, Chris A. Weyer, Wayne C. Cross, William M. Henderson, Brooks D. Kellar, Jon J. Kjerengtroen, Lidvin Welsh, Jeffry Starkovich, John South Dakota School of Mines and Technology Rapid City SD 57701 United States Air Force Research Laboratory Space Vehicles Directorate Kirtland AFB NM 87117 United States Northrop-Grumman Space Technologies Redondo Beach CA 90278 United States Department of Mechanical Engineering 501 E. St. Joseph St. United States Materials Engineering and Science Program 501 E. St. Joseph St. United States Department of Materials and Metallurgical Engineering 501 E. St. Joseph St. United States Integrated Structural Systems SE Bldg. 472 3550 Aberdeen Ave. United States NGST Structures and Mechanisms Product Center Mail Stop R4-2112 One Space Park

No abstract available

ISBN: (纸本)1563478080

No abstract available

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