Search results for: modeling-a-ships-ferromagnetic-signatures

Modeling a Ship s Ferromagnetic Signatures

Author : John Holmes
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Ferromagnetic models of ships and submarines that predict or reproduce their magnetic signatures have found applications in the development of both offensive and defensive military systems from World War II to the present. The mathematical basis of generalized coordinate systems will be presented and demonstrated with example applications to analytic spherical and prolate spheroidal magnetic ship models. In addition, the advantages and pitfalls of using complex finite-element- and boundary-element numerical techniques to predict high-order near-field ship signatures will be discussed, followed by a short description of the design and testing of complementary physical scale models. Extrapolation of measured magnetic signatures from testing environments to threat areas using semi-empirical math models will be presented, along with an explanation of their inherent instabilities and methods for regularizing them. These magnetic ship signature modeling techniques are used today in designing optimized signature reduction systems that have a minimum impact on ships and their systems. The discussion will be closed with an important discussion of the verification and validation of magnetic models of surface ships and submarines.

Modeling a Ship s Ferromagnetic Signatures

Author : John J. Holmes
File Size : 76.56 MB
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Ferromagnetic models of ships and submarines that predict or reproduce their magnetic signatures have found applications in the development of both offensive and defensive military systems from World War II to the present. The mathematical basis of generalized coordinate systems will be presented and demonstrated with example applications to analytic spherical and prolate spheroidal magnetic ship models. In addition, the advantages and pitfalls of using complex finite-element- and boundary-element numerical techniques to predict high-order near-field ship signatures will be discussed, followed by a short description of the design and testing of complementary physical scale models. Extrapolation of measured magnetic signatures from testing environments to threat areas using semi-empirical math models will be presented, along with an explanation of their inherent instabilities and methods for regularizing them. These magnetic ship signature modeling techniques are used today in designing optimized signature reduction systems that have a minimum impact on ships and their systems. The discussion will be closed with an important discussion of the verification and validation of magnetic models of surface ships and submarines.

Reduction of a Ship s Magnetic Field Signatures

Author : John Holmes
File Size : 28.19 MB
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Decreasing the magnetic field signature of a naval vessel will reduce its susceptibility to detonating naval influence mines and the probability of a submarine being detected by underwater barriers and maritime patrol aircraft. Both passive and active techniques for reducing the magnetic signatures produced by a vessel's ferromagnetism, roll-induced eddy currents, corrosion-related sources, and stray fields are presented. Mathematical models of simple hull shapes are used to predict the levels of signature reduction that might be achieved through the use of alternate construction materials. Also, the process of demagnetizing a steel-hulled ship is presented, along with the operation of shaft-grounding systems, paints, and alternate configurations for power distribution cables. In addition, active signature reduction technologies are described, such as degaussing and deamping, which attempt to cancel the fields surrounding a surface ship or submarine rather than eliminate its source. Table of Contents: Introduction / Passive Magnetic Silencing Techniques / Active Signature Compensation / Summary

Reduction of a Ship s Magnetic Field Signatures

Author : John Holmes
File Size : 34.22 MB
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Decreasing the magnetic field signature of a naval vessel will reduce its susceptibility to detonating naval influence mines and the probability of a submarine being detected by underwater barriers and maritime patrol aircraft. Both passive and active techniques for reducing the magnetic signatures produced by a vessel's ferromagnetism, roll-induced eddy currents, corrosion-related sources, and stray fields are presented. Mathematical models of simple hull shapes are used to predict the levels of signature reduction that might be achieved through the use of alternate construction materials. Also, the process of demagnetizing a steel-hulled ship is presented, along with the operation of shaft-grounding systems, paints, and alternate configurations for power distribution cables. In addition, active signature reduction technologies are described, such as degaussing and deamping, which attempt to cancel the fields surrounding a surface ship or submarine rather than eliminate its source. Table of Contents: Introduction / Passive Magnetic Silencing Techniques / Active Signature Compensation / Summary

NL ARMS Netherlands Annual Review of Military Studies 2018

Author : H. Monsuur
File Size : 49.35 MB
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This book provides a comprehensive study of border control: from data analysis andinformation warfare, frameworks for command and control, and game-theoretic riskmanagement, up to the (optimal) deployment of law enforcement missions. Innovative about this book is that it approaches the subject from several angles, aimingto connect theory and practice of law enforcement missions with risk management and/or quantitative modelling. Some chapters focus on legal challenges and informationwarfare, while others provide quantitative modelling of military asset deployment inthe area of interest, or show the benefits of cooperative wireless sensor networks forborder control. A case study of the Dutch Border Security Team supplements the theory. The publication is ideally suited for reference use by students, academicians, researchersand professionals in the field of border control and related areas. H. Monsuur is Professor of Military Operations Research, J.M. Jansen is AssociateProfessor of Operational ICT, and F.J. Marchal is Lecturer of International/MilitaryLaw at the Faculty of Military Sciences of the Netherlands Defence Academy in DenHelder, The Netherlands.

The proceedings of the 16th Annual Conference of China Electrotechnical Society

Author : Jinghan He
File Size : 57.64 MB
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Simulation of Electrochemical Processes II

Author : V.G. DeGiorgi
File Size : 54.84 MB
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This book contains papers presented at the Second International Conference in this successful series, which presents and discusses the state-of-the-art on the computer simulation of corrosion, electrochemical processes and the electrical and electromagnetic fields associated with them.Modern industry applies a wide range of electrochemical processes to protect against corrosion, provide surface treatments and to manufacture products. This book focuses on the computer modelling of these industrial processes and techniques by examining the developments of computational models and their application in practice.Featured topics include: Cathodic Protection Systems; Modelling Methodologies; Electrodeposition and Electroforming; Modelling of Coatings; Modelling Stress Corrosion, Cracking and Corrosion Fatigue; Modelling and Corrosion of Surface Coatings; Interference and Signature Control; Anodic Protection; Electrocoating and Plating; Optimisation of Control Systems; Detection and Monitoring of Corrosion; Measurement Techniques; Fuel on Photovoltaic Cells; Electrolysis Reactors; Comparison of Experimental Measurements and Computer results, Case Studies.

Exploitation of a Ship s Magnetic Field Signatures

Author : John J. Holmes
File Size : 82.57 MB
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Surface ship and submarine magnetic field signatures have been exploited for over 80 years by naval influence mines, and both underwater and airborne surveillance systems. In this book, author John Holmes presents the generating mechanism of the four major shipboard sources of magnetic fields, along with a detailed description of the induced and permanent ferromagnetic signature characteristics. Holmes presents a brief historical summary of magnetic naval mine development during World War II followed by a discussion of important improvements found in modern weapons, including an explanation of the damage mechanism for non-contact explosions. This is followed by a brief historical discussion of underwater and airborne submarine surveillance systems and magnetic field sensing principles, in which mathematical formulations are presented for computing expected target signal strengths and noise levels for several barrier types.Also outlined is a multi-layered defensive strategy against naval mines, with graphical explanations of the relationships between ship signature reduction and minefield clearing effectiveness. Equations for estimating geomagnetic, ocean surface wave, platform, and vector sensor motion noises are presented along with simple algorithms for their reduction.

Accurate Computation of Mathieu Functions

Author : Andrew Peterson
File Size : 84.8 MB
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This lecture presents a modern approach for the computation of Mathieu functions. These functions find application in boundary value analysis such as electromagnetic scattering from elliptic cylinders and flat strips, as well as the analogous acoustic and optical problems, and many other applications in science and engineering. The authors review the traditional approach used for these functions, show its limitations, and provide an alternative "tuned" approach enabling improved accuracy and convergence. The performance of this approach is investigated for a wide range of parameters and machine precision. Examples from electromagnetic scattering are provided for illustration and to show the convergence of the typical series that employ Mathieu functions for boundary value analysis.

Analysis and Design of Substrate Integrated Waveguide Using Efficient 2D Hybrid Method

Author : Xuan Hui Wu
File Size : 39.19 MB
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Substrate integrated waveguide (SIW) is a new type of transmission line. It implements a waveguide on a piece of printed circuit board by emulating the side walls of the waveguide using two rows of metal posts. It inherits the merits both from the microstrip for compact size and easy integration, and from the waveguide for low radiation loss, and thus opens another door to design efficient microwave circuits and antennas at a low cost. This book presents a two-dimensional fullwave analysis method to investigate an SIW circuit composed of metal and dielectric posts. It combines the cylindrical eigenfunction expansion and the method of moments to avoid geometrical descritization of the posts. The method is presented step-by-step, with all the necessary formulations provided for a practitioner who wants to implement this method by himself. This book covers the SIW circuit printed on either homogeneous or inhomogeneous substrate, the microstrip-to-SIW transition and the speed-up technique for the simulation of symmetrical SIW circuits. Different types of SIW circuits are shown and simulated using the proposed method. In addition, several slot antennas and horn antennas fabricated using the SIW technology are also given. Table of Contents: Introduction / SIW Circuits Composed of Metallic Posts / SIW Circuits with Dielectric Posts / Even-Odd Mode Analysis of a Symmetrical Circuit / Microstrip to SIW Transition and Half Mode SIW / SIW Antennas