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MAGNETOHYDRODYNAMIC SUBMARINE PROPULSION SYSTEMS

NAVAL ENGINEERS JOURNAL 1991年第3期103卷 141-157页

作者： SWALLOM, DW SADOVNIK, I GIBBS, JS GUROL, H NGUYEN, LV VANDENBERGH, HH Daniel W. Swallomis the director of military power systems at Avco Research Laboratory Inc. a subsidiary of Textron Inc. in Everett Mass. Dr. Swallom received his B.S. M.S. and Ph.D. degrees in mechanical engineering from the University of Iowa Iowa City Iowa in 1969 1970 and 1972 respectively. He has authored numerous papers in the areas of power propulsion and plasma physics and currently is a member of the Aerospace Power Systems Technical Committee of the AIAA. Dr. Swallom has directed various programs for the development of advanced power generation systems lightweight power conditioning systems and advanced propulsion systems for marine applications. His previous experience includes work with Odin International Corporation Maxwell Laboratories Inc. Argonne National Laboratory and the Air Force Aero Propulsion Laboratory. Currently Dr. Swallom is directing the technical efforts to apply magnetohydrodynamic principles to a variety of propulsion and power applications for various marine vehicles and power system requirements respectively. Isaac Sadovnikis a principal research engineer in the Energy Technology Office at Avco Research Laboratory Inc. a subsidiary of Textron Inc. He received his B.S. in engineering (1974) B.S. in physics (1975) M.S. in aeronautics and astronautics (1976) and Ph.D. in physics of fluids (1981) at the Massachusetts Institute of Technology. Dr. Sadovnik has been involved in research work funded by DARPA concerning the use of magnetohydrodynamics for underwater propulsion. He has built theoretical models that predict the hydrodynamic behavior of seawater flow through magnetohydrodynamic ducts and their interaction with the rest of the vehicle (thrust and drag produced). In addition Dr. Sadovnik has been involved in research investigations geared toward the NASP program concerning the use of magnetohydrodynamic combustion-driven accelerator channels. Prior to joining Avco Dr. Sadovnik was a research assistant at MIT where he conducted experimental and

Magnetohydrodynamic propulsion systems for submarines offer several significant advantages over conventional propeller propulsion systems. These advantages include the potential for greater stealth characteristics, increased maneuverability, enhanced survivability, elimination of cavitation limits, greater payload capability, and the addition of a significant emergency propulsion system. These advantages can be obtained with a magnetohydrodynamic propulsion system that is neutrally bouyant and can operate with the existing submarine propulsion system power plant. A thorough investigation of magnetohydrodynamic propulsion systems for submarine applications has been completed. During the investigation, a number of geometric configurations were examined. Each of these configurations and mounting concepts was optimized for maximum performance for a generic attack class submarine. The optimization considered each thruster individually by determining the optimum operating characteristics for each one and accepting only those thrusters that result in a neutrally buoyant propulsion system. The results of this detailed optimization study show that the segmented, annular thruster is the concept with the highest performance levels and greatest efficiency and offers the greatest potential for a practical magnetohydrodynamic propulsion system for attack class submarines. The optimization study results were used to develop a specific point design for a segmented, annular magnetohydrodynamic thruster for an attack class submarine. The design point case has shown that this thruster may be able to provide the necessary thrust to propel an attack class submarine at the required velocity with the potential for a substantial acoustic signature reduction within the constraints of the existing submarine power plant and the maintenance of neutral buoyancy. This innovative magnetohydrodynamic propulsion system offers an approach for submarine propulsion that can be an important contributio

关键词： Ship Propulsion

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Rapid design of testable, high-performance/capacity associative memories 2

Rapid design of testable, high-performance/capacity associat...

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2nd IEEE Symposium on Parallel and Distributed Processing, SPDP 1990

作者： Miller, P.M. Hurson, A.R. Computer Engineering Program Department of Electrical and Computer Engineering Pennsylvania State University University ParkPA16802 United States

ISBN: (纸本)0818620870

VLSI technology has created the opportunity for designers to develop special-purpose application-specific architectures based on associative processing techniques. However the diversity of these applications creates a need for a generalized methodology to quickly produce high-capacity associative chips with different functionalities. The paper introduces such a scheme for designing special-purpose content-addressable memories (CAMs). An overall CAM organization suitable for most special-purpose associative chips is presented and the design, layout, and performance of its modular components is discussed. An example CAM is examined to show the performance and area efficiency of CAMs designed using the proposed scheme. The paper also introduces an improved, highly compact theta -search associative cell. Finally, the testing of CAMs using this organization is discussed. © 1990 IEEE.

关键词： Associative storage

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Phase space topography and the Lyapunov exponent of electrocorticograms in partial seizures

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Brain Topography 1990年第3期2卷 187-201页

作者： Iasemidis, Leonidas D. Chris Sackellares, J. Zaveri, Hitten P. Williams, William J. Bioengineering Program Department of Electrical Engineering and Computer Science United States Epilepsy Program Department of Neurology University of Michigan Ann Arbor 48109-0316 MI 1920 Taubman Center/0316 1500 E. Medical Center Drive United States

Electrocorticograms (ECoG's) from 16 of 68 chronically implanted subdural electrodes, placed over the right temporal cortex in a patient with a right medial temporal focus, were analyzed using methods from nonlinear dynamics. A time series provides information about a large number of pertinent variables, which may be used to explore and characterize the system's dynamics. These variables and their evolution in time produce the phase portrait of the system. The phase spaces for each of 16 electrodes were constructed and from these the largest average Lyapunov exponents (L's), measures of chaoticity of the system (the larger the L, the more chaotic the system is), were estimated over time for every electrode before, in and after the epileptic seizure for three seizures of the same patient. The start of the seizure corresponds to a simultaneous drop in L values obtained at the electrodes nearest the focus. L values for the rest of the electrodes follow. The mean values of L for all electrodes in the postictal state are larger than the ones in the preictal state, denoting a more chaotic state postictally. The lowest values of L occur during the seizure but they are still positive denoting the presence of a chaotic attractor. Based on the procedure for the estimation of L we were able to develop a methodology for detecting prominent spikes in the ECoG. These measures (L^*) calculated over a period of time (10 minutes before to 10 minutes after the seizure outburst) revealed a remarkable coherence of the abrupt transient drops of L^* for the electrodes that showed the inital ictal onset. The L^* values for the electrodes away from the focus exhibited less abrupt transient drops. These results indicate that the largest average Lyapunov exponent L can be useful in seizure detection as well as a discriminatory factor for focus localization in multielectrode analysis. © 1990 Human Sciences Press, Inc.

关键词： chaos ECoG epileptogenic focus localization Lyapunov exponents partial epileptic seizures phase space

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Rapid design of testable, high-performance/capacity associative memories

Rapid design of testable, high-performance/capacity associat...

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International Symposium on Parallel and Distributed Processing (IPDPS)

作者： P.M. Miller A.R. Hurson Computer Engineering Program Department of Electrical and Computer Engineering Pennsylvania State University University Park PA USA

关键词： Testing computer aided manufacturing CADCAM Cams Random access memory Very large scale integration Application software Read-write memory Associative memory Logic

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Use of computer simulation in the development of an algorithm for analysis of paced electrocardiograms

Use of computer simulation in the development of an algorith...

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computers in Cardiology (CinC)

作者： S.E. Greenhut J.M. Jenkins Bioengineering Program and Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

A computer model of the interaction between heart and artificial pacemaker is developed which simulates a variety of dual-chamber device responses in the context of 25 possible arrhythmia classes. The heart-pacemaker interaction (HPI) model includes specifications of cardiac, pacemaker, and noise distribution parameters which permit random simulation of pacemaker failure. It simulates random pacemaker output, capture, and sensing malfunctions. The model has been used to train an automated, knowledge-based algorithm designed to analyze paced electrocardiograms for pacemaker function and malfunction. By allowing the straightforward simulation of numerous arrhythmia/pacemaker failure scenarios, the model has significantly reduced the amount of clinical testing and therefore the development time otherwise required.< >

关键词： computer simulation Algorithm design and analysis Pacemakers Electrocardiography Rhythm Heart Computational modeling Context modeling Testing Myocardium

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Effects of aging on polyimide: a study of bulk and interface chemistry

Effects of aging on polyimide: a study of bulk and interface...

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IEEE Workshop on Solid-State Sensor and Actuator

作者： M.C. Buncick D.D. Denton Department of Electrical and Computer Engineering and Materials Science Program University of Wisconsin Madison Madison WI USA

An analysis is presented of polyimides (PIs) exposed to heat and humidity stress over long periods. Electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared (FTIR) spectroscopy were used to investigate the basic physical mechanisms that affect PI when stressed. The results show that changes are confined to a surface layer at the PI-air interface. ESCA data show significant changes at the PI-air interface and that the PI-Si interface remains unchanged. FTIR transmission data indicate that the bulk chemistry is unaffected by such exposure. The surface chemistry is characterized by a significant reduction in the pyromellitic dyanhydride (PMDA) moiety and changes in the bonding of oxygen. There appear to be changes in the imide structure for the PI surface, but the mechanisms of change require further study. This has reliability implications for microelectronic systems using PI as a dielectric.< >

关键词： Aging Polyimides Spectroscopy Infrared spectra Chemistry Humidity Stress Electrons Chemical analysis Fourier transforms

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computer simulation of heart-pacemaker interaction

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Journal of Electrocardiology 1990年第SUPPL.期23卷 156-156页

作者： Greenhut, Saul E. MacDonald, Robert S. Jenkins, Janice M. Department of Electrical Engineering Computer Science The University of Michigan Ann Arbor MI United States the Bioengineering Program The University of Michigan Ann Arbor MI United States

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A Ray Tracing program For Studying Acoustic Telemetry With Auvs

A Ray Tracing Program For Studying Acoustic Telemetry With A...

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OCEANS

作者： J. McCalla K.C. Baldwin J.D. Irish D.R. Blidberg K. Sivaprasad Ocean Systems Engineering Houston TX USA Ocean Engineering Program University of New Hampshire Durham NH USA Ocean process Analysis Laboratory University of New Hampshire Durham NH USA Marine Systems Engineering Laboratory University of New Hampshire Durham NH USA Electrical and Computer Engineering Department University of New Hampshire Durham NH USA

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SHIP SERVICE electrical SYSTEMS - DESIGNING FOR SURVIVABILITY

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NAVAL ENGINEERS JOURNAL 1990年第5期102卷 32-36页

作者： CERMINARA, J KOTACKA, RO John Cerminara:is a principal engineer with Westinghouse Machinery Technology Division Electrical Systems Department. He holds a B.S. degree in electrical engineering from the University of Pittsburgh. He is a registered professional engineer and a member of IEEE ASNE and the Ship Steering Group of the Combat Survivability Division of ADPA. Mr. Cerminara has had over 30 years of multidiscipline experience ranging from engineering and construction in heavy industry to standards and publications. Past assignments include DOE/ NASA wind turbine project manager for Westinghouse and task leader of MTD electrical systems. Most recent assignments have included hull mechanical and electrical (HM&E) distributive system survivability analyses of the LSD-41 mobility mission area and application and validation of NavSea computer-aided design of Survivable Distributive System (CADSDiS) Program. Rolf O. Kotacka:is presently a ship systems engineer in the Ship Systems Engineering Branch of the Naval Sea Systems Command Engineering Directorate where his primary responsibility is ship system survivability. He is a 1977 graduate of SUNY Maritime College where he received his bachelor of engineering degree in marine electrical engineering as well as a U.S. Coast Guard Third Assistant Engineer License and a commission in the U. S. Naval Reserve. Upon graduation Mr. Kotacka was employed by Charleston Naval Shipyard as a field engineer until 1981 where he gained his background in surface ship HM&E systems and equipment. He then transferred to the Supervisor of Shipbuilding Conversion and Repair Groton where he served as a senior electrical engineer monitoring the design and construction of Trident and 688 class submarines and received the Meritorious Unit Citation. Prior to his present position Mr. Kotacka was the life cycle manager for diesel generator sets in the Naval Sea Systems Command's Generators Branch. He has coauthored several papers dealing with power generation for ASE and SNAME. Mr. Kotacka is also a lieutena

This paper highlights the survivability concerns in the design of ship service power systems. The paper gives a brief description of what constitutes a typical ship service electric power system and concentrates on electric power generation and associated controls. Established survivability design principles and guidelines are highlighted and the application of those guidelines are discussed. General Specifications (Gen Specs) for Ships of the U.S. Navy are cited as the cornerstone for design. Specific design criteria are cited as well as the rationale associated with the survivability design guidelines pertaining to power generation and distribution. The application of these survivability design guidelines plus the use of the deactivation diagram/damage tolerance analysis cited in the Gen Spec section 072e will enhance overall design and help ensure survivable electric power systems for surface combatants.

关键词： Warships

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AN APPROACH TO EXPERIMENTAL EVALUATION OF REAL-TIME FAULT-TOLERANT DISTRIBUTED COMPUTING SCHEMES

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IEEE TRANSACTIONS ON SOFTWARE engineering 1989年第6期15卷 715-725页

作者： KIM, KH Computer Engineering Program Department of Electrical Engineering University of California Irvine CA 92717

A testbed-based approach to the evaluation of fault-tolerant distributed computing schemes is discussed. The approach is based on experimental incorporation of system structuring and design techniques into real-time distributed computing testbeds centered around tightly coupled microcomputer networks. The effectiveness of this approach has been confirmed through some experiments conducted in the author's laboratory. Primary advantages of the testbed-based approach include the relatively high accuracy of the data obtained on timing and logical complexity as well as the relatively high degree of assurance that can be obtained on the practical effectiveness of the scheme evaluated. This paper discusses various design issues encountered in the course of establishing the basic microcomputer network testbed facilities and augmenting them to support some experiments conducted. The shortcomings of the testbeds that have been recognized are also discussed together with the desired extensions of the testbeds. Some of the desired extensions are beyond the state of the art in microcomputer network implementation. [ABSTRACT FROM AUTHOR]

关键词： Distributed computer system distributed recovery block experimental validation fault tolerance real-time computer system recovery temporary blackout testbed

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