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EFFECTS OF THE SIdEWALL THErMAL CONdITIONS ON THE GAS-FLOWS IN A rAPIdLY rOTATING CYLINdEr

FLUId dYNAMICS rESEArCH 1991年第3-4期7卷 119-129页

作者： HYUN, JM PArK, JK Department of Mechanical Engineering Korea Advanced Institute of Science and Technology P.O. Box 150 Chong Ryang Seoul Korea Refrigeration Appliances Division R&D center Daewoo Electronics Co. Ltd. No. 604 Yonghyun-Dong Nam-gu Incheon Korea

Numerical studies are presented of the flows of a gas in a rapidly rotating cylindrical container. The reference Ekman number is small, and the peripheral Mach number is O(1). Fluid motions are induced by small differences in the boundary temperatures. In order to assess the effects of thermal boundary conditions at the sidewall on the flow structure and temperature field, three types of conditions at the sidewall are adopted, i.e. a linearly varying, an insulated, and an isothermal temperature condition. Analyses are made of comprehensive and systematically organized numerical results, which have been acquired by solving the complete, compressible Navier-Stokes equations. Contour maps of the temperature and stream function are constructed. In the short-bowl regime, the closed circulation near the sidewall is strongly affected by the thermal conditions;the importance of the work done by compression produced in the radial motions is emphasized. However, the axial flow in the inner inviscid region is found to be mainly controlled by the Ekman suction. In the long-bowl regime, the global flow structure is considerably influenced by the sidewall thermal condition. This is due principally to the significant diffusion of momentum in the radial direction.

关键词： Flow of fluids

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SOME rOOT PrOPErTIES OF rECUrSIVE WEIGHTEd MEdIAN FILTErS

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SIGNAL PrOCESSING 1991年第3期25卷 337-344页

作者： HAN, YG SONG, IH PArK, YS Research Group 3 Buchun R&D Center Semiconductor Business Samsung Electronics 82-3 Dodang-Dong Chung-Ku Buchun Kyunggi Korea Department of Electrical Engineering Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong Dong Yuseong Gu Daejeon 305-701 Korea Software 1 Lab. Operation Research Center Seoul ESS Korea Telecom 17 Umyum-Dong Sucho-Gu Seoul 137-140 Korea

The weights of weighted median and recursive weighted median filters have close relationship with the root signal characteristics of these filters. In this paper, we find a set of conditions on weights under which a recursive weighted median filter preserves monotone or locally monotone sequence and that under which any input sequence converges to a locally monotone sequence after a finite number of passes. We also find a set of conditions on weights under which the output of a recursive weighted median filter is the same as that of a recursive median filter.

关键词： rECUrSIVE WEIGHTEd MEdIAN FILTEr rOOT PrOPErTY WEIGHT VECTOr

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dEVELOPMENT OF A LITHIUM rECHArGEABLE BATTErY FOr UNdErWATEr VEHICLE PrOPULSION - rEPLY

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NAVAL ENGINEErS JOUrNAL 1991年第4期103卷 130-130页

作者： SMITH, PH JAMES, Sd CHUA, dL Patricia H. Smithis group leader of the R&D Group in the Electrochemistry Branch Code R33 of the Naval Surface Warfare Center Silver Spring Md. She obtained her Ph.D. in inorganic chemistry at the University of Maryland in 1981. Dr. Smith is managing the High Energy Battery Project funded by the Office of Naval Technology to develop power sources for the next generation naval systems. A major thrust of this project is developing rechargeable lithium batteries to propel underwater naval vehicles. Dr. Smith is the editor in chief of the High Energy Battery Newsletter. David L. Chuais the manager of lithium battery R&D at Alliant Techsystems Inc.—Power Sources Center (formerly Honeywell) Horsham Penn. He is responsible for the research and development of both primary and rechargeable lithium technologies. He received his M.S. in metallurgical engineering at the University of Arizona in 1969 and a Ph.D. in materials engineering at Rensselaer Polytechnic Institute in 1973. Dr. Chua has over 15 years experience in lithium electrochemical research received 5 patents and authored numerous papers on lithium battery technology. Stanley D. Jamesobtained his Ph.D. in physical chemistry at the Imperial College of Science London in 1959. In 1967 he joined the Naval Surface Warfare Center Silver Spring Md. and is presently the senior technical consultant to the R&D Group in the Electrochemistry Branch Code R33. Dr. James has authored 45 papers and is the technical editor of the High Energy Battery Newsletter.

The Navy is researching lithium rechargeable batteries as a possible replacement for silver oxide/zinc cells in powering the next generation of naval underwater vehicles. This paper summarizes progress made with the most promising lithium system — lithium/cobalt oxide, which has 2.5 times the theoretical energy density of silver oxide/zinc. Using small (0.03 Ah) laboratory cells, optimization was completed for cathode fabrication and electrolyte composition. Even at three times the required discharge rate, cycle life obtained with these cells was over double the program goal. Furthermore, a significant fast charge capability was demonstrated when charging was conducted at constant potential versus constant current. This laboratory cell technology was scaled up successfully to 2.5 Ah cell test fixtures. Presently, engineering development is underway at the 10 Ah level in hermetically sealed, instrumented subcells. Preliminary data are achieving the required energy densities for at least 15 cycles with tests still continuing. The optimized design resulting from the 10 Ah tests is being incorporated into 30 Ah cells.

关键词： Submarines

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FOrMATION rEACTIONS OF THETl2Ca2Ba2Cu3O10ANdTl2Ca1Ba2Cu2O8PHASES

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Modern Physics Letters B 1990年第13期4卷 885-893页

作者： T.W. HUANG M.P. HUNG T.S. CHIN H.C. KU S.E. HSU Department of Materials Engineering National Cheng Kung University Tainan 70100 Taiwan China Dept. of Materials Sciences & Engineering National Tsing Hua University Hsinchu 30043 Taiwan China Department of Physics National Tsing Hua University Hsinchu 30043 Taiwan China Materials R&D Center Chung Shan Institute of Sciences & Technology Lung Tang 32526 Taiwan China

Solid state formation of the superconducting phases in the Tl–Ca–Ba–Cu–O system has been studied by dTA, TGA , and Xrd analyses. It was found that the formation reaction of the high T c Tl 2 Ca 2 Ba 2 Cu 3 O 10 and the low T c Tl 2 Ca 1 Ba 2 Cu 2 O 8 phases takes place at around 900°C and 840°C respectively, within a reaction time of 30 minutes. Activation energies of these reactions are found to be 50 kcal/mol and 35 kcal/mol, respectively. The use of precursor Ca 3 BaCu 3 O x yielded superconducting materials with superior characteristics as compared to those prepared from the direct mixture.

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A PrACTICAL APPrOACH TO THE dESIGN, OPErATION, ANd MONITOrING OF INSITU SOIL-VENTING SYSTEMS

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GrOUNd WATEr MONITOrING ANd rEMEdIATION 1990年第2期10卷 159-178页

作者： JOHNSON, PC STANLEY, CC KEMBLOWSKI, MW BYErS, dL COLTHArT, Jd Paul C. Johnson Ph.D. joined Shell Development Co.'s (Westhollow Research Center Room EC-649 P.O. Bo 1380 Houston TX 77251–1380) Environmental Science Department in 1987 after earning his B.S. in chemical engineering from the University of California Davis and his Ph.D. in chemical engineering from Princeton University. His current areas of research include the development and evaluation of soil treatment processes modeling and measuring transport phenomena in porous media and the development of transport models for predicting emissions and exposures used in envvironmental risk assessments. Curtis C Stanley received his degree in geology with an engineering minor from North Carolina State University in 1979. He is currently a senior hydrogeologist for Shell Oil Co. (Westhollow Research Center 2236 Two Shell Plaza Houston TX 77082) and is responsible for hydrogeologic response at Shell's retail facilities. Stanley is a Certified Professional Geological Scientist and also a Certified Ground Water Professional with the NWWA's Association of Ground Water Scientists and Engineers. He is also a member of API's Ground Water Technology Taskforce and is an EPA Peer Reviewer. Marian W. Kemblowski Ph.D. is a senior research engineer in the Environmental Science Department at Shell Development Co. (Westhollow Research Center Houston TX 77082) where he has worked since 1985. He obtained his M.S. degree in civil engineering from the Technical University of Warsaw Poland in 1973 and his Ph.D. in ground water hydrology from the Institute for Land Reclamation in Warsaw Poland in 1978. In 1980–1981 he was a visiting hydrologist in the New Mexico School of Mining and Technology. From 1981 to 1985 he worked as an assistant scientist at the University of Kansas. His principal research interests are in the areas of numerical analysis transport in porous media and ground water monitoring systems. Dallas L. Byers is a technical associate in the Environmental Science Department at Shell Development. After receivin

When operated properly, in situ soil venting or vapor extraction can be one of the most cost-effective remediation processes for soils contaminated with gasoline, solvents, or other relatively, volatile compounds. The components of soil-venting systems are typically off-the-shelf items, and the installation of wells and trenches can be done by reputable environmental firms. However, the design, operation, and monitoring of soil-venting systems are not trivial. In fact, choosing whether or not venting should be applied at a given site is a difficult decision in itself. If one decides to utilize venting, design criteria involving the number of wells, well spacing, well location, well construction, and vapor treatment systems must be addressed. A series of questions must be addressed to decide if venting is appropriate at a given site and to design cost-effective in situ soil-venting systems. This series of steps and questions forms a “decision tree” process. The development of this approach is an attempt to identify the limitations of in situ soil venting, and subjects or behavior that are currently difficult to quantify and for which future study is needed.

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COMPArATIVE STrUCTUrAL LIFE ASSESSMENT OF PATrOL BOAT BOTTOM PLATING

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NAVAL ENGINEErS JOUrNAL 1990年第3期102卷 253-262页

作者： AYYUB, BM WHITE, GJ BELLWrIGHT, TF PUrCELL, ES Bilal M. Ayyub:is currently an associate professor of civil engineering at the University of Maryland. He received his B.S. degree in civil engineering from the University of Kuwait in 1980. He completed both his M.S. (1981) and Ph.D. (1983) in civil engineering at the Georgia Institute of Technology. Dr. Ayyub has an extensive background in risk-based analysis. He is engaged in research work involving structural reliability marine structures and mathematical modeling using the theories of probability statistics and fuzzy sets. His research work has been sponsored by the National Transportation Safety Board National Science Foundation U.S. Coast Guard Department of Defense State of Maryland and University of Maryland. He is the author of more than 100 publications in national and international journals conference proceedings and reports. Dr. Ayyub was a recipient of the ASNE “Jimmie” Hamilton Award for 1985 the ASCE “Outstanding Research Oriented Paper” in theJournal of Water Resources Planning and Managementfor 1987 and Edmund Friedman Young Engineer Award for Professional Achievement from ASCE for 1989. Gregory J. White:is an associate professor of naval architecture at the U.S. Naval Academy. He received his B.S. degreein engineering mechanics from Vanderbilt University in 1975 an M.E. degree in naval architecture from the University of California Berkeley in 1981 and a Ph.D. in civil engineering (structures) from the University of Maryland in 1986. Dr. White served on active duty with the U.S. Navy from 1975 to 1979 as a junior officer in the engineering and operations departments of Pacific Fleet destroyers. Prior to coming to the Naval Academy he worked at Mare Island Naval Shipyard in the scientific code and in the R&D division of Exxon International company's Tanker Department. Dr. White is the author of more than two dozen technical articles and reports and is one of the U.S. representatives to the International Ship and Offshore Structures Congress (ISSC). His research interests lie in t

The estimation of an absolute life expectancy of a structure is a complex process and the results are expected to have relatively large levels of uncertainty. In this study, a comparative analysis is undertaken between two different patrol boats. This is an approach which results in a higher confidence level because certain factors common to both boats can be eliminated by assuming them to be at constant normal levels. The study is limited to the critical forward bottom plating and takes into account the differences in material, plate dimensions, operational profile, structure and loading of the two vessels. Two failure modes, plastic plate deformation and fatigue, are considered, and a novel approach to plate wastage is included. Many factors affect the structural life of a vessel. They include structural type, operational profile, structural details, loads, inspection and maintenance, design methods, safety factors, corrosion, and environmental factors. There are three types of uncertainty associated with these factors; namely, physical randomness, statistical uncertainties, and model uncertainties. The method described is designed to address these uncertainties. The objective of the paper is to present the reliability-based structural life assessment method, and then to use it to evaluate and compare the structural performance of the forward bottom plating of the two patrol boats. The results of the evaluation are presented in the form of graphs and tables in order to facilitate the comparative evaluation. The method is performed within a computer-based format which allows parametric sensitivity analysis of several variables including the size of the plating panel, thickness, operational profile and loading. The sensitivity of the structural life expectancy of the forward bottom plating to variations in these parameters is evaluated.

关键词： Naval Vessels

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An Adaptive Control of Nonlinear Time-Varying Hydraulic Servo Systems

An Adaptive Control of Nonlinear Time-Varying Hydraulic Serv...

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American Control Conference (ACC)

作者： H.J. Park H.S. Cho B.S. Hyun Precision Instrument R&D Center Samsung Aerospace Industries Limited South Korea Professor Department of Production Engineering Division of Mechanical Engineering Senior Research Engineer Korea Advanced Institute of Science and Technology Seoul South Korea

This paper deals with a velocity control of nonlinear hydraulic servo systems with time-varying parameters. An adaptive model following control algorithm is adopted to assign the desired dynamics regardless of the nonlinearity and time-varying feature of the system. To show the validities of the scheme. a series of simulation are performed for various design parameters.

关键词： Adaptive control Time varying systems Servomechanisms Valves Control systems Velocity control Nonlinear dynamical systems Fluid dynamics Temperature control Aerodynamics

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CUrrENT LIMITING PrOTECTOr FOr LOW-VOLTAGE, HIGH-CUrrENT APPLICATIONS

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NAVAL ENGINEErS JOUrNAL 1989年第3期101卷 267-273页

作者： EMErY, FT WU, JL Dr. Franklin T. Emery:is a senior engineer in the Electromechanical Systems Department at the Westinghouse R&D Center Pittsburgh Pa. Dr. Emery received his B.S. (1974) M.S. (1977) and Ph.D. (1983) degrees in electrical engineering from the University of Pittsburgh Pittsburgh Pa. His primary work is in applied research on electrical systems associated with large power systems both for Navy ship applications and for the commercial power industry. He is presently involved in the development of the electronics for a high current high speed interrupter for use in the protection of power distribution systems on board Navy surface ships. His prior experience is in fiber optic technology design and application for both SDI and Navy applications. He is a Senior Member of IEEE and is a professional registered engineer in Pennsylvania and Florida. Dr. Jiing L. Wu:is a senior research scientist in the Electromechanical Systems Department at the Westinghouse R&D Center Pittsburgh Pa. Dr. Wu received his B.S. degree in mechanical engineering from Taiwan Cheag Kung University Taiwan in 1965 M.S. in mechanical engineering from the University of Wisconsin Madison in 1969 and Ph.D. in engineering science from the State University of New York Buffalo New York in 1974. He has participated in research and development work in pulsed power switching devices for electromagnetic launchers circuit breakers for commercial and naval electrical systems and fault current limiting devices. He is presently the principal investigator and project manager of a team developing the current limiting protector for the Naval Sea Systems Command.

A pyrotechnic current limiting interrupter (CLI) has been developed for use in high current, 60-Hz, 480-volt, 3-phase electrical bus circuits. The interrupter design combines a high continuous current (4800 A rms) rating with a high current (210 kA rms sym.) interruption capability. Its electrical power loss is low and its mechanical construction uses no complex moving mechanisms. The CLI is used with a current sensor, electronic logic, and energy storage circuitry. The current sensor continuously monitors the current through the CLI and provides input to logic circuits which analyze and determine the validity of the fault condition. Both the fault current magnitude and rate of current increase are used in combination to make the decision when to activate the CLI. Using stored electrical energy, a detonator is activated causing an explosive cord to generate shock waves sufficient to cut the current carrying conductors. detection and initiation of the interruption process occurs within 1/4 cycle for a symmetrical fault and within 1/2 cycle for an asymmetrical fault. The first peak in the fault current is limited to the first half cycle.

关键词： Electric Circuit Breakers

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ESTIMATION OF STrUCTUrAL SErVICE LIFE OF SHIPS

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NAVAL ENGINEErS JOUrNAL 1989年第3期101卷 156-166页

作者： AYYUB, BM WHITE, GJ PUrCELL, ES P.E. Bilal M. Ayyub:is currently an associate professor of civil engineering at the University of Maryland. He received his B.S. degree in civil engineering from the University of Kuwait in 1980. He completed both his M.S. (1981) and Ph.D. (1983) in civil engineering at the Georgia Institute of Technology. Dr. Ayyub has an extensive background in risk-based analysis and design simulation and construction engineering. He is engaged in research work involving structural reliability bridges marine structures and mathematical modeling using the theories of probability statistics and fuzzy sets. His research work is sponsored by the National Transportation Safety Board the National Science Foundation the U.S. Coast Guard the State of Maryland and the University of Maryland. Dr. Ayyub is a member of ASNE the American Society of Civil Engineers (ASCE) the American Concrete Institute (ACI) the Committee on Forensic Engineering of ASCE and the Committee on Structural Safety of ACI. He is the author of more than three dozen publications in national and international journals conference proceedings and reports. Dr. Ayyub received the ASNE “Jimmie” Hamilton Award for 1985 and the ASCE “Outstanding Research Oriented Paper” in the Journal of Water Resources Planning and Management for 1987. Gregory J. White:is an associate professor of naval architecture at the U.S. Naval Academy. He received his B.S. degree in engineering mechanics from Vanderbilt University in 1975 an M.E. degree in naval architecture from the University of California Berkeley in 1981 and a Ph.D. in civil engineering (structures) from the University of Maryland in 1986. Dr. White served on active duty with the U.S. Navy from 1975 to 1979 as a junior officer in the engineering and operations departments of Pacific Fleet destroyers. Prior to coming to the Naval Academy he worked at Mare Island Naval Shipyard in the scientific code and in the R&D division of Exxon International Company's Tanker Department. Dr. White is a lieutenant commande

A methodology for the structural life assessment of a ship's structure is suggested. The methodology is based on probabilistic analysis using reliability concepts and the statistics of extremes. In this approach, the estimation of structural life expectancy is based on selected failure modes. All possible failure modes of the ship must be investigated and the most likely paths to structural failure identified. For the purpose of illustration two failure modes are considered in this study. They are plate plastic deformation and fatigue cracking. Structural life based on these two failure modes is determined for an example vessel. The methodology determines the probability of failure of the ship's structural components according to the identified failure modes as a function of time. The results can be interpreted as the cumulative probability distribution function (CdF) of structural life. due to the unknown level of statistical correlation between failure modes, limits or bounds on the CdF of the structural life are established. The limits correspond to the extreme cases of fully correlated and independent failure modes. The CdFs of structural life are determined for two inspection strategies; namely, inspection every year and inspection every two years with a warranty inspection at the end of the first year. The meaning of the results for the case investigated in this study is that, for example, given an inspection strategy of two years and a desired life of 15 years, there is a 72% chance that the vessel will not experience enough partial damage‘ in the failure modes identified to constitute reaching the “end of structural life” as defined.

关键词： Ships

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POLE ASSIGNMENT IN rOTATING-dISK VIBrATION CONTrOL USING COMPLEX MOdAL STATE FEEdBACK

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MECHANICAL SYSTEMS ANd SIGNAL PrOCESSING 1988年第3期2卷 225-241页

作者： BYUN, SW LEE, CW Precision Instrument R&D Center Samsung Aerospace Seoul Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology Seoul Korea

Modal state feedback controls of rotating disk vibrations in real and complex fields are formulated and compared. Pole assignment in real modal space necessitates the simultaneous assignment of eigenvalues and eigenvectors to uniquely determine the feedback gain matrix. Pole assignment in complex modal space, however, uniquely determines the feedback gain matrix, because preservation of the isotropic nature in the uncontrolled and controlled modal systems only allows the assignment of the isotropic eigenstructure. The proposed complex modal control scheme reduces the order of the system to be dealt with. It also minimises the required control energy and the transient magnitudes of the state.

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