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LOW-FLOW PURGING ANd SAMPLING OF GROUNd-WATER MONITORING WELLS WITH dEdICATEd SYSTEMS

GROUNd WATER MONITORING ANd REMEdIATION 1995年第1期15卷 116-123页

作者： PULS, RW PAUL, CJ Robert W. Puls is currently employed at the R.S. Kerr Environmental Research Laboratory (RSKERL) U.S. EPA Subsurface Systems Branch in the Research Division (Acta OK 74820). He received his Ph.D. in soil and water science from the University of Arizona. Following completion of his doctorate he worked on the High Level Nuclear Waste Repository Research Program (DOE) investigating the fate and transport of radionuclides in ground water. He has been employed at RSKERL since 1987. Recent topics of particular interest include the following: surface chemical factors which influence colloidal stability and transport in subsurface systems surface redox-mediated transformations of inorganic contaminants in soils and ground water in situ remediation of contaminated metals sites and the development of ground water sampling techniques that provide representative and reproducible contaminant concentrations for the purposes of risk assessment remedial performance at hazardous waste sites. Cynthia J. Paul is currently employed by the U.S. EPA at RSKERL. She received her bachelor's degree from East Central University in 1990 and will complete her master's degree in environmental science at the University of Oklahoma in 1995. Her research interests include adsorption-desorption and oxidation-reduction reactions of inorganics as related to subsurface contaminant fate and transport. Other interests include ground water sampling methodologies and turbidity effects on volatile organic contaminants.

A field study was conducted to assess purging requirements for dedicated sampling systems in conventional monitoring wells and for pumps encased in short screens and buried within a shallow sandy aquifer. Low-flow purging methods were used, and wells were purged until water quality indicator parameters (dissolved oxygen, specific conductance, turbidity) and contaminant concentrations (chromate, trichloroethylene, dichloroethylene) reached equilibrium. Eight wells, varying in depth from 4.6 to 15.2 m below ground surface, were studied. The data show that purge volumes were independent of well depth or casing volumes. Contaminant concentrations equilibrated with less than 7.5 L of purge volume in all wells. Initial contaminant concentration values were generally within 20 percent of final values. Water quality parameters equilibrated in less than 10 L in all wells and were conservative measures for indicating the presence of adjacent formation water. Water quality parameters equilibrated faster in dedicated sampling systems than in portable systems and initial turbidity levels were lower.

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PARALLEL ANd dISTRIBUTEd TLM COMPUTATION WITH SIGNAL-PROCESSING FOR ELECTROMAGNETIC-FIELd MOdELING

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INTERNATIONAL JOURNAL OF NUMERICAL MOdELLING-ELECTRONIC NETWORKS dEVICES ANd FIELdS 1995年第3-4期8卷 169-185页

作者： SO, PPM ESWARAPPA, C HOEFER, WJR NSERC/MPR Teltech Research Chair in RF Engineering Department of Electrical and Computer Engineering University of Victoria Victoria British Columbia V8W 3P6 Canada Poman So received his B.Sc. degree in computer science and physics from the University of Toronto Toronto Onatario Canada in 1985. He obtained his B.A. Sc. and M.A.Sc. degrees in electrical engineering (summa cum laude) from the University of Ottawa Ottawa Ontario Canada in 1987 and 1989 respectively. Mr So was a research engineer in the University of Ottawa from January 1989 to October 1991 his research interests included CAD techniques of microwave circuits and numerical methods for electromagnetic wave modelling. He specialized in the development of electromagnetic engineering CAD software and successfully implemented a number of electromagnetic wave simulators based on the two-dimensional and three-dimensional transmission-line matrix methods. From August 1990 to February 1991 he accompanied Professor W. J. R. Hoefer to Rome Italy and Sophia Antiopolas France. During that time he implemented a parallel version of the 3D-TLM simulator for the CM-2 Connection Machine using C-Star and X Windows Library. He is a research engineer and a Ph.D. student at the University of Victoria Victoria British Columbia Canada. He ported the 2D- and 3D-TLM simulators to DECmpp 1200 massively parallel computer using MPL C and C++. He also combined OSA90/hope a commercially available microwave CAD program with a 2D-TLM simulation module for geometry optimization using the Datapipe technique of OSA90/hope. Recently he has developed a distributed client-server computing technique for the TLM method this technique could accelerate the TLM simulation by more than an order of magnitude. Channabasappa Eswarappa received the M.Tech. degree in electrical engineering from the Indian Institute of Technology Kanpur India in 1983 and Ph. D. degree from the University of Ottawa Canada in 1990. He worked as an Assistant Executive Engineer and later as

This paper describes the implementation of transmission-line matrix (TLM) method algorithms on a massively parallel computer (dECmpp 12000), the technique of distributed computing in the UNIX environment, and the combination of TLM analysis with Prony's method as well as with autoregressive moving average (ARMA) digital signal processing for electromagnetic field modelling. By combining these advanced computation techniques, typical electromagnetic field modelling of microwave structures by TLM analysis can be accelerated by a few orders of magnitude.

关键词： Mathematical models

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A dISTRIBUTEd MEdIA ACCESS PROTOCOL FOR PACKET RAdIO NETWORKS ANd PERFORMANCE ANALYSIS .2. NETWORK SET-UP TIME ANd dATA RATE

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第1期8卷 49-63页

作者： PONd, LC LI, VOK Communication Sciences Electrical Engineering Systems University of Southern California Los Angeles CA 90089-2565 U.S.A. Lawrence C. Pond received the M.Sc. and Ph.D. degrees in electrical engineering from the University of Southern California in 1983 and 1990 respectively. Dr. Pond is currently a scientist at Hughes Space and Communications Company having joined in 1980. He has worked in the fields of communication system design mobile communication network and spacecraft payload design. He is currently working on the development of satellite-based ATM transport and switching architectures for BISDN and Defense Information System Network amlications. Dr. Pond is a member of IEEE. Victor O. K. Li was born in Hong Kong in 1954. He received his SB SM and Sc.D. degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology Cambridge Massachusetts in 1977 1979 and 1981 respectively. Since February 1981 he has been with the University of Southern California (USC) LOS Angeles California where he is Professor of Electrical Engineering and Director of the USC Communication Sciences Institute. He has published 150 technical papers and has lectured and consulted extensively around the world. His research interests include high-speed communication networks personal communication networks intelligent networks distributed databases queueing theory graph theory and applied probability. Dr. Li is very active in the Institute of Electrical and Electronic Engineers (IEEE) having been a member of the Computer Communications Technical Committee since 1983 and having served as Chairman from 1987–1989. He served as Chairman of the Los Angeles Chapter of the IEEE Information Theory Group from 1983–1985. He is the Steering Committee Chair of the International Conference on Computer Communications and Networks (IC3 N) General Chair of the 1st Annual IC3N held in San Diego California in June 1992 General Chair and Technical Program Chair of the 4th IEEE Workshop on Comp

In this, the second part of a two-part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set-up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade-off between the data rate and set-up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set-up time trade-off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes.

关键词： PACKET RAdIO NETWORK EPLRS dISTRIBUTEd NETWORK TdMA VIRTUAL CIRCUITS MULTIHOP NETWORK BOUNdEd dELAY MOBILITY NETWORK SET-UP TIME HIERARCHICAL NETWORK NETWORK dATA RATE

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GENERATION OF HYdROGEN GAS A RESULT OF dRILLING WITHIN THE SATURATEd ZONE

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GROUNd WATER MONITORING ANd REMEdIATION 1994年第4期14卷 140-147页

作者： BJORNSTAd, BN MCKINLEY, JP STEVENS, TO RAWSON, SA FREdERICKSON, JK LONG, PE Bruce N. Bjornstad is a senior research scientist in the Geology and Geophysics Group of the Pacific Northwest Laboratory (P.O. Box 999 Richland WA 99352). Since earning an M.S. degree in geology from Eastern Washington University in 1980 he has been involved in characterization and modeling studies related to the sedimentology and geohydrology of the Hanford Site. More recently he has become involved in the geochemical and microbiological characterization of the deep subsurface. James P. McKinley is a research scientist in the Interfacial Geochemistry Group at the Pacific Northwest Laboratory. He received a Ph.D. in geology from the University of New Mexico in 1990. His work includes studies of aqueous geochemistry and chemical interactions at the solid-solution interface. Todd O. Stevens is a staff scientist in the Environmental Microbiology Group at Pacific Northwest Laboratory. He received a Ph.D. in bacteriology from the University of Idaho in 1989. His work has focused on bioremediation of contaminated soils and sediments and on microbial ecology of anaerobic habitats. More recently he has participated in microbial ecology studies of the deep terrestrial subsurface. Shirley A. Rawson is manager of the Transport Geochemistry Group at Pacific Northwest Laboratory. She earned a Ph.D. in geological sciences in 1984 from University of Oregon. For the last three years she has been co-investigator of a DOE- sponsored research project on the hydrogeological and geochemical processes influencing the occurrence of subsurface microorganisms. Her research interests include the effects of diagenetic reactions (microbial and abiotic) on sediment permeability and the impacts on solute transport. James K. Fredrickson is a staff scientist in the Environmental Microbiology Group at Pacific Northwest Laboratory. He received a Ph.D. in microbiology and soil science from Washington State University. He has been involved in the DOE's Subsurface Science Program for more than eight years and is currently serving as a scientifi

Hydrogen gas was discovered within the steel casing above standing water in a percussion-drilled borehole on the Hanford Site in south-central Washington state. In situ measurements of the borehole fluids indicated anoxic, low-Eh (<-400 mV) conditions. Ground water sampled from adjacent wells in the same formation indicated that the ground water was oxygenated. H2 was generated during percussion drilling, due to the decomposition of borehole waters as a result of aqueous reactions with drilled sediment and steel from the drilling tools or casing. The generation of H2 within percussion-drilled boreholes that extend below the water table may be more common than previously realized. The ambient concentration of H2 produced during drilling was limited by microbial activity within the casing-resident fluids. H2 was generated abiotically in the laboratory, whereby sterilized borehole slurry samples produced 100 times more H2 than unsterilized samples. It appears that H2 is metabolized by microorganisms and concentrations might be significantly greater if not for microbial metabolism.

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MATERIALS ASPECTS OF dAMAGE TOLERANCE ANd RELIABILITY OF SHIP STRUCTURES ANd COMPONENTS

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NAVAL ENGINEERS JOURNAL 1994年第4期106卷 192-207页

作者： KHAN, MZS SAUNdERS, dS BURCH, IA MOURITZ, AP Dr. M. Z. Shah-Khan: currently a research scientist received his Bachelor of Engineering degree in Mechanical Engineering from Osmania University India in 1978. He took postgraduate work at Iowa State University receiving an M.S. degree in Metallurgy in 1981. In 1983 he joined University of New South Wales Australia and obtained the Doctor of Philosophy degree in Metallurgy in 1986. In 1986 he assumed his present position where he has been active in the research of fatigue and fracture of high strength naval construction steels in support of the Naval Ship Structure Research Program. His recent work has been in the development and application of techniques for the measurement of residual stress during the fabrication of a submarine hull. Dr. D. S. Saunders: B. Appl. Sc. (Hons) Adelaide Ph.D. Monash is a principal research scientist and has been involved in research into the fatigue and fracture behaviour of steels and aluminum alloys. He has worked on the development of fracture toughness specimens for artillery projectiles and rocket motors and has undertaken development and application of elastic-plastic fracture toughness techniques to high strength steels for military applications. More recently he has studied the fatigue behaviour of carbon fibre composite laminates for aircraft applications. Present research involves the application of composite materials to naval structures and the development of fracture mechanics methods which can predict fracture properties in materials under high rates of loading. Dr. Saunders is a member of the Institution of Engineers of Australia and is affiliated with the Materials Society and the Composite Structures Society of the IEAust. Mr. Ian A. Burch: Dip. Appl. Sci. in Sec. Metallurgy Royal Melbourne Institute of Technology is an experimental officer and is involved in assessing the fracture properties of high strength hull steels for ship and submarine use. He is currently involved in developing the crack arrest fracture toughness test for assessing the dynami

The design and development process prior to the fabrication of maritime structures such as merchant ships, naval surface ships and submarines include the specification of a range of materials required to perform under most adverse conditions of environment and operational loads. The damage tolerance and reliability of such structures can only be assured through appropriate materials selection, application of regorous testing methodologies and through-life inspection and monitoring. The importance of the consideration of damage tolerance and reliability of maritime structures can be gauged by the consequences of in-service failures;for example, the break-up of merchant ships resulting in environmental disasters, loss of lives and wartime damage of naval ships and submarines. Factors that lead to service failures include corrosion, fatigue, corrosion fatigue, low toughness and poor design, and often these factors occur in combination. The range of materials used in maritime structures is diverse and includes mild steel (ship) plate, micro-alloyed steels, aluminium alloys and monolithic and foam sandwich glass fibre laminates. These materials all have different responses to the environmental and loading conditions and consequently extensive materials testing programs are necessary to put damage tolerance and reliability indicators in place. This paper addresses the materials and testing aspects of damage tolerance and reliability assessment of maritime structures, and deals broadly with corrosion and corrosion fatigue testing;fracture toughness testing;measurement of residual stresses within the structure;damage assessment and life calculations. The paper discusses testing methodologies that obtain essential property data for various materials under a range of environmental and loading conditions. The paper briefly addresses the application of property data to the prediction of the behavior of maritime structures and components as well as application to life prediction

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TECHNICAL ISSUES REGARdING SATELLITE PACKET-SWITCHING

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 257-267页

作者： IVANCIC, Wd CHU, P SHYY, dJ National Aeronautics and Space Administration Lewis Research Center Cleveland Ohio 44135 USA. A design engineer in the Digital Technology Branch of the Space Electronics Division. He has extensive experience in satellite communications systems modulation and coding on-board switching and routeing and high speed digital design. Since joining NASA in 1982 Mr. Ivancic has been responsible for the development of a variety of matrix switch controllers ground terminal equipment numerous pieces of special test equipment a beacon controller for the SARSAT program (Search and Rescue Satellite) and a time-shared decoder for a processing satellite. In addition Mr. Ivancic has been technical contract monitor on a number of advanced communications technology contracts including the Advanced Modulation Technology Development a 5 GHz fibre-optic link and multi-programmable modem study. He was awarded the B.S.E.E. and M.S.E.E. degrees by Cleveland State University in 1982 and 1986 respectively. Cleveland State University Cleveland Ohio 44115 USA. Currently an assistant professor of Electrical Engineering Department at Cleveland State University. He obtained the M.S. and Ph.D. degrees from Iowa State University majoring in Electrical and Computer Engineering. His research interests include high-speed computer networks digital systems and neural networks applications. He is a member of Sigma Xi Phi Kappa Phi as well as the IEEE and ACM. ComSearch Reston Virginia 22091 USA. Received the B.S. degree in electrical engineering from National Chiao-Tung University Hsin-Chu Taiwan in 1983 and the M.S. and Ph.D. degrees in electrical engineering from Georgia Institute of Technology Atlanta GA in 1986 and 1990 respectively. From June 1987 to October 1987 he worked for the Department of Neurology Emory University Atlanta as a Programmer. From September 1989 to December 1989 he worked for the Advanced Development Laboratory. AMP Inc. Atlanta as a Test Engineer. From February 1990 to August 1993 he wor

Many concepts for advanced communication satellite networks have recently been proposed. Critical technical issues relating to satellite packet switching for meshed very small aperture terminal networks and broadband ... 详细信息

关键词： FAST PACKET SWITCH BISdN MESHEd VSAT ON-BOARd PROCESSING

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HYBRId SATELLITE ANd TERRESTRIAL NETWORKS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 313-327页

作者： CHITRE, dM SHYY, dJ EphREMIdES, A GUPTA, S COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871–9475 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN/Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Received the B.S. degree in electrical engineering from national Chiao-Tung University Hsin-Chu Taiwan in 1983 and the M.S. and Ph.D. degrees in electrical engineering from Georgia Institute of Technology Atlanta GA in 1986 and 1990 respectively. From June 1987 to October 1987 he worked for the Department of Neurology Emory Univers

The role of satellite communications in networks that provide new services, such as frame relay and multimedia, is investigated. Both passive and active (on-board switching/processing) satellite systems are considered. Novel techniques are developed for each system to demonstrate, via detailed analysis and simulation, how the communications bandwidth agility of multipoint/broadcast satellite channels, and the on-board switching/processing, makes it feasible to provide these new services via hybrid satellite and terrestrial networks in a resource-efficient manner.

关键词： HYBRId NETWORKS ON-BOARd PROCESSING FRAME RELAY

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PERFORMANCE OF A PRIORITIZEd ON-BOARd BASEBANd SWITCH FOR A MULTISERVICE MULTIBEAM SATELLITE

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 283-297页

作者： BOHM, S ELHAKEEM, AK HACHICHA, M Department of Electrical and Computer Engineering Concordia University 1455 De Maisonneuve Blvd. West Montreal H3A 1M8 Canada Was born in Montreal Canada on 14 September 1966. He received the B. Eng. degree in electrical engineering from Concordia University Montreal Canada in 1989. He is at present completing the M.A.Sc. degree in electrical engineering at Concordia University. (S'75–S'79–M'79–SM'86) received the Ph.D. degree from Southern Methodist University Dallas TX in 1979. He spent the next two years working as a Visiting Professor in Egypt after which he moved to Ottawa Canada in 1982. He assumed teaching and research positions in Carleton and Manitoba Univerities and later moved to Concordia University Montreal Canada in 1983 where he is now a Professor in the Electrical and Computer Engineering Department. He has published numerous papers in IEEE and international journals in the areas of spread spectrum and networking. He is a well-known expert in these areas and serves as a consultant to many companies. His current research interests include wide-band metropolitan networks switching architectures and performance of on-board multibeam satellites acquisitionless CDMA networks code distribution and orthogonalization of CDMA signals responsive congestion control for ATM-based networks ARQ techniques and investigation of the novel SUGAR CDMA systems in fading channels. Dr. Elhakeem is a Senior Member of the Canadian Electrical Engineering Society and Armed Forces Association. He has chaired numerous technical sessions in IEEE Conferences was the Technical Program Chairman for IEEE Montech 1986 Montreal Canada. Dr. Elhakeem is the key guest editor of theIEEE Journal of Selected Areas in Communicationsfor the May June issues 1993 covering CDMA networks. Advanced Technology & Networks VISTAR Telecommunications Inc. Ottawa Ontario K1G 3J4 Canada An Associate Director of Advanced Technology & Networks Group VISTAR Telecommunications Inc. Ottawa Canada. He is also an Adjunct Pr

In this paper, we study the performance of a prioritized on-board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses both input and output buffering, switch speed-up as well as a two-phase head-of-line resolution algorithm, in order to reduce the buffer loss while maintaining acceptable user delays. The minimum required buffer capacity and switch speed-up for each service in a prioritized environment are found under uniform traffic conditions. It is shown that under uniform traffic conditions, only minimal buffering and switch speed-up are needed even for the lowest priority users. The performance dependence on the switch size is also substantially reduced with head of line resolution and buffering even in a prioritized environment.

关键词： SWITCH ON-BOARd BASEBANd MULTIBEAM PRIORITIZEd HEAd-OF-LINE UNIFORM LOAd SPEEd-UP

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AN ARCHITECTURE dESIGN APPROACH FOR LARGE SATELLITE NETWORKS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 197-210页

作者： COTNER, C INUKAI, T COMSAT World Systems 6560 Rock Spring Drive Bethesda MD 20817 USA. Director Customer Technical Support for COMSAT World Systems. He directs support to U.S. users of the INTELSAT satellite network particularly in the areas of certifying that performance of earth-stations is in accordance with system requirements and in supporting the unique needs of television customers. Mr. Cotner's primary technical interests are earth-station design transmission analysis and high power amplifiers. Mr. Cotner has been with COMSAT for over 25 years. Most recently he served as Director of Technical Liaison and Analysis responsible for much of COMSAT World Systems research and development programme for high-level technical interaction with customers such as AT&T and MCI and for initiatives to improve the quality of international satellite transmission. He has also held technical management positions in COMSAT Laboratories COMSAT General where he was a Division Director Earth Segment Engineering and COMSAT World Systems where he represented the U.S. Signatory on the INTELSAT Board of Governors Technical Advisory Committee for five years. Mr. Cotner is a colonel (retired) in the Signal Corps U.S. Army Reserve where he was assigned to several mobilization positions related to satellite communications including a tour of duty on the Joint Staff. Awarded the degree of B.S.E. (cum-laude) in Electrical Engineering by Princeton University. Mr. Cotner also holds an M.S.E. from Cornell University and is a Commandants List graduate of the U.S. Army Command and General Staff College. He and his wife Sharon live in Silver Spring Maryland. COMSAT Laboratories 22300 COMSAT Drive Clarksburg MD 20871 USA. Received the BS and MS degrees in Communications Engineering from the Tokyo Electrical Engineering College Tokyo Japan and the Ph.D. degree in Electrical Engineering from the City University of New York New York. Dr. Inukai is a Principal Scientist in the Network Technology Division of COMSAT Laboratories. He directs res

designing a world-wide satellite network that consists of hundreds of user sites and thousands of circuit connections is a complex problem, which involves selecting a set of candidate satellites and satellite beams/frequency bands from among numerous existing and planned satellites, evaluation of circuit connectivity, earth-station compatibility and sizing, and estimating transponder loading. The design process may also require assessment of the impact of a different set of satellites and modified user traffic requirements on the space segment, the earth-station types and quantity, and the total system cost. Although a conventional design approach based on link-by-link and site-by-site analysis provides accurate results, it is time-consuming and impractical for developing high-level network architectures in a time-constrained environment. A design technique is proposed which employs a set of rules for satellite network design, in combination with extensive databases of satellite parameters, earth-station parameters and user traffic requirements, to synthesize a network architecture. The technique is particularly useful for performing high-level trade-offs among alternative architectures in terms of space segment requirements, the number and type of earth-stations and overall system cost. Once the desired architecture has been selected, a detailed design may be developed using conventional methods.

关键词： SATELLITE NETWORK dESIGN RULE-BASEd dESIGN FIXEd SATELLITE SERVICES FdMA INTELSAT BANdWIdTH REQUIREMENTS TRANSPONdER CAPACITY

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MOdAL TEST OF JONES,JOHN,PAUL (ddG-53) MAST ANd MAST-MOUNTEd ANTENNAS

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NAVAL ENGINEERS JOURNAL 1994年第2期106卷 110-117页

作者： MCLEAN, M HILL, J COBB, R RANdALL, F Mark McLean:has been with the Naval Sea Systems Command for eight years and is currently with Code 03K. He is responsible for survivability assessment of combat systems equipment. He has participated in all U.S. Navy ship shock tests conducted since 1985 and is responsible for failure assessment and redesign efforts for numerous combat systems equipment. He was selected by the NavSea Program Offices to be a member of the damage assessment teams providing early inspection in the Samuel B. Roberts (FFG-58) and Princeton (CG-59) incidents. Mr. McLean graduated from the University of Virginia in 1983 with an MS degree in chemical engineering. Jerry Hill:has been with NKF Engineering Inc. for twelve years. Currently managing the structural dynamics department Mr. Hill is responsible for numerous survivability related analysis and design efforts. This includes dynamic mathematical simulation and prediction field testing and qualification and full-scale ship shock testing. Mr. Hill graduated from the University of Maryland with a BS degree in mechanical engineering. He is a registered Professional Engineer. Dr. Richard Cobb:has been with NKF Engineering Inc. as a senior engineer since 1990. He is involved with research and development projects including dynamics modal testing vibration design instrumentation and underwater explosion. Prior to joining NKF he was an instructor of mechanical engineering at Virginia Tech. Dr. Cobb holds a Ph.D. in mechanical engineering from Virginia Tech with dissertation research in the areas of experimental modal analysis and frequency response function estimation using Fast Fourier transform methods. Fred Randall:has been manager of the noise shock and vibration department at Bath Iron Works since 1987. As such he is responsible for all dynamic measurements conducted by the shipyard. From 1982 to 1987 he was with TRW in the survivability department conducting investigations of shock propagation structural media interaction and soils modeling and analysis. Mr. Randall gr

A modal test of the John Paul Jones (ddG-53) mainmast structure and mast-mounted antennas was conducted. The test was part of a larger effort to accurately determine dynamic characteristics of the ''as-built'' mast/antenna system and survivability in the vibration and underwater explosion (UNdEX) shock environment. Previous mathematical analysis of the ddG-51 class mast and antennas predicted response acceleration levels during a shock trials scenario to be excessive in some areas. The modal test results now provide, however, confirmed dynamic response characteristics including mode shapes, frequencies, and damping for the structure. The test data accounts for the flexibility of ship's structure including the deckhouse supporting the mast. In addition, the natural frequencies of the antennas were determined for the response range of the mast structure with the flexibility of the supporting foundations taken into account. Using the test results, a finite element model of the mast structure and antennas was built accurately representing the dynamic characteristics of the system. dynamic transient shock analysis was conducted to provide response predictions of the mast and antennas using the validated model. Any potential response amplification conditions that might result in failure during shock trials were identified.

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