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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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Effects of structural imperfections on constant-feedback-gain control of a spatial structure

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Computing Systems in engineering 1990年第2-4期1卷 601-606页

作者： Aubert, B.H. Abel, J.F. Lu, J. Thorp, J.S. School of Civil and Environmental Engineering Program of Computer Graphics Cornell University Ithaca NY 14853 United States School of Electrical Engineering Cornell University Ithaca NY 14853 United States

The numerical sensitivity of a constant-feedback-gains controller to random structural imperfections is examined using the results of a series of finite element analyses. The basic finite element model, which uses linear beam-column elements, is a two-dimensional simplification of a large (10 m long) three-dimensional frame currently undergoing testing at Cornell University. The cross-sectional properties, nodal coordinates, and masses of the models were randomly varied within four different ranges of maximum imperfection. Twenty transient dynamic analyses were run for each range of structural perturbation. Each analysis used a different random distribution of imperfections. The results of the finite element analyses show that the optimal control configuration, found by dynamic programming, exhibited unacceptable sensitivity to small perturbations of the structural model. A second, nearly optimal, control configuration was found to be more robust with respect to structural imperfections. © 1990.

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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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computer-AIDED-DESIGN METHODS FOR PROPELLER FILLET GAUGES

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 202-208页

作者： ALLEN, DW VINOSKI, WS OVERTON, BA David W. Allen:is a senior computer scientist at the Machinery Technology Division Westinghouse Electric Corporation Large Pa. He received the B.A. degree in mathematics from Grinnell College and the M.S. degree in computer science from the University of Pittsburgh. His career with Westinghouse has been divided between assignments in engineering and computer applications. Mr. Allen has published eight technical papers. He received the George Westinghouse Signature A ward of Excellence for his work on the development of the GAGES computer program for designing propeller gages. He is a member of the Association for Computing Machinery (ACM) and the Institute of Electrical and Electronics Engineers (IEEE). Walter S. Vinoski:is a project engineer at the Machinery Technology Division Westinghouse Electric Corporation Large Pa. and was instrumental in the development of the GAGES computer program. He was awarded the George Westinghouse Signature Award of Excellence for his work on the GAGES program. Mr. Vinoski has six years of marine propulsion system experience specifically with propellers. He earned a B.S. degree in electronics engineering and minored in mathematics at the Ohio Institute of Technology. He is a member of the American Society of Naval Engineers. Bernard A. Overton:graduated from North Carolina Agricultural and Technical State University Greensboro N.C. in 1958 with a B.S. degree in mechanical engineering. Within two years of joining the U.S. Army Mr. Overton was honorably discharged as a first lieutenant. Mr. Overton worked seven years at Philadelphia Naval Shipyard in the following areas: shafting shafting alignment bearing reactions noise and vibration surveys propellers and propeller blade gage designs. In 1967 Mr. Overton transferred to the Navy Engineering Center. He has worked on main propulsion devices such as water jets propellers (both submarine and surface ship) and propeller blade gages. Mr. Overton was responsible for the establishment of the Naval Inspectors Propeller Certif

One of the most complicated forms encountered in engineering design is that of the marine propeller. The complexities arise from the complicated hydrodynamic surfaces of the propeller blades and the complicated manner in which the blades are oriented with and attached to the hub. Where propeller blades are attached to the hub, the blade shape is blended into the shape of the hub. The geometry of this region is particularly complicated. The shape of the blend is called a fillet, and the blending region is called the fillet region. Sheet metal gages conforming to various blade surface contours are used in the manufacture and inspection of propellers. Five different types of gages define the shape of the propeller in different regions. Fillet gages are such gages that define the shape of propeller blades in the fillet region. This paper describes a new computer-aided method for designing fillet gages. Previous methods of fillet gage design required the designer to follow a complicated layout procedure of determining where a particular unfilleted blade contour intersected the hub. The design of the fillet was then done in another layout procedure. Newly developed numerical procedures incorporated in a computer program have reduced the time required to design a complete set of gages (including fillet gages) from up to several weeks to hours.

关键词： Propellers

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