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This paper proposes a way to represent the anisotropic nonlinear superconducting properties using a discrete model for magnetization with the corresponding critical parameters, equivalent to the Power Law model for currents. This simplified model makes it possible to analyze magnetic systems with superconducting elements in a stationary mode, which reduces the calculation time. Using of proposed model is demonstrated by the calculation of force interactions between high-temperature superconducting (HTS) samples and permanent magnet in zero-field-cooling (ZFC) and field-cooling (FC) modes. HTS bulks in the form of a prism and stack made of HTS tape are considered. The calculation of the electromagnetic field was carried out using the method of integral equations for field sources. The data of calculations are compared with the results of experimental studies. [ABSTRACT FROM AUTHOR]

Under wideband and especially ultrawideband (short pulse) excitation, the electromagnetic fields, after encounters with a propagation or scattering environment, reveal features which range from highly resolved spikes or dips to smooth oscillations at early and late observation times, respectively. Time-domain (TD) analytic modelling should be structured around wave objects which relate features (observables) in data to distinct features in the environment. A strategy to this end, named observable-based parametrization (OBP), is proposed here. The rules are learned from frequency- and time-domain asymptotics applies to spatial and spectral domain representations of tractable prototype problems. This leads to self-consistent hybrid combinations OBP-TD travelling (wavefront) and oscillatory (resonant) synthesizing basis fields; the latter include novel TD leaky modes for guiding wave channels and TD Bragg modes for periodic arrays. These concepts are illustrated by examples. [ABSTRACT FROM AUTHOR]

Accurate and simple magnetic material behavior law is necessary to correctly model complete electromagnetic systems. In this paper, a new formulation based on the scalar quasi-static hysteresis Preisach model extended to dynamic behavior using fractional derivation dynamic contribution is proposed. The fractional contribution is solved using convolution which highly reduces the numerical issues. The order of the fractional derivation provides a new degree of freedom and allows to correctly obtain simulation results on a very large frequency bandwidth. By using such formulation, space discretization techniques (finite differences, finite elements) are avoided which are highly space and time consuming while keeping the global simulation results precise. The numerical implementation of the problem and some experimental validations are shown in this paper. [ABSTRACT FROM AUTHOR]

The article focuses on proposal and analysis of the physical models suitable to stress simulation and limit state prediction of components made of composite structure on Onyx basis. The observed parameters are physical properties of matrix and reinforcement. The additive manufacturing technologies also allow the production of complex shape constructions with cavities. The cavities are regions characteristic of damage initiations, but a realization of experimental measurements on inner surfaces of them to predict failure is problematic. Therefore, the exploitation of appropriate physical models and subsequently mathematical models is a method for observing of material behaviour using selected physical quantities beyond surface layers. The modelling of composite structures is viable using physical models, which working principle is based on homogenization of structure, for instance, representative volume elements (RVE). The primary disadvantage of RVE models is a complicated analysis of physical properties at inhomogeneity places of reinforcement. The physical model proposed in this paper describes each fibre separately regarding authentic physical properties and precise determination of fibre deposition in the matrix. Implementation of FEM programs with a primary objective to perform formation and analysis of the physical models, provides solution of various multiphysical problems, such as nonlinear behaviour of material induced by contact, temperature variation or interaction with other environments (temperature, fluid, electromagnetic fields), and so on. The main aspect of the presented concept is the generation of computational models with a precise definition of fibre deposition in the composite structure. The numerical analysis of loading and limit state prediction was executed on models of the composite structure. The structure includes onyx as a thermoplastic matrix and carbon fibres. The fundamental physical criterions for damage initiation assessment were stress state and strain at critical locations of matrix and reinforcement. [ABSTRACT FROM AUTHOR]

The paper deals with a mathematical model aimed to study electromagnetic and hydrodynamic processes in the inductor-ingot system during continuous DC mold casting. Experimental studies implied measurements of the vertical components of the liquid phase of meridional flows using the ultrasonic Doppler velocity probe. Results of mathematical and physical simulations were compared; dependences were obtained proving the validity of the proposed mathematical model. [ABSTRACT FROM AUTHOR]

The present paper considers a mathematical model of the process of volumetric induction heating of cylindrical pieces in a cylindrical inductor. The model is based on a machine for volumetric induction heating of R–ITO–630/1–A–L type with a SMK UB 2F2 power source. The inductor equivalent parameters have been calculated. To verify the results obtained from the model, a 2D model has been built in Comsol Multiphysics. [ABSTRACT FROM AUTHOR]

This paper describes iterative methods for the high frequency electromagnetic analysis using the finite element method of Maxwell equations including displacement current. The conjugate orthogonal conjugate gradient method has been widely used to solve a complex symmetric system. However, the conventional method suffers from oscillating convergence histories in large-scale analysis. In this paper, to solve large-scale complex symmetric systems arising from the formulation of the E method, an iterative substructuring method like the minimal residual method is presented, and the performance of the convergence of the method is evaluated by numerical results. As the result, the proposed method shows a stable convergence behavior and a fast convergence rate compared to other iterative methods. [ABSTRACT FROM AUTHOR]

The nonconformal domain decomposition methods (DDMs) of the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) are presented for computing large electromagnetic scattering/radiation problems. The numerical performance of different transmission conditions between finite element method (FEM) subdomains, and FEM and BI domains is studied in this paper. The Dirichlet transmission condition (DTC) employed at the interface between FEM and BI domains has faster convergence than the Robin-type transmission condition, and this finding is different from the conclusions for the FEM DDMs published in the literature. Furthermore, the cement-element (CE)-based dual-primal finite element tearing and interconnecting (FETI-DP) DDM has faster convergence than the Lagrange-multiplier-based FETI-DP method under the FE-BI system, and is also different from that under the system of the FEM with the absorbing boundary condition (FEM-ABC). It shows that the DDMs of FE-BI-MLFMA have some essential differences from those of FEM-ABC. The analysis of these numerical phenomena is presented in this paper. Further comparison between the DDMs of FE-BI-MLFMA and FEM-ABC demonstrates that the DDMs of FE-BI-MLMFA have essential advantages over those of FEM-ABC. Various numerical experiments confirm the accuracy, efficiency, and flexibility of the nonconformal DDM of FE-BI-MLFMA, which is the CE-based FETI-DP DDM with DTC connecting FEM and BI. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with the following semilinear Schrödinger equation with electromagnetic fields and critical growth for sufficiently large , where , and its zero set is not empty, is the critical Sobolev exponent, is a constant such that the operator might be indefinite but is non-degenerate. Using variational method and modified Nehari-Pankov method, we prove the equation admits a least energy solution which localizes near the potential well . The results we obtain here extend the corresponding results for the Schrödinger equation which involves critical growth but does not involve electromagnetic fields. [ABSTRACT FROM AUTHOR]

This paper proposes a robust frequency-domain method to tune the d–q decoupled control system used in Modular Multilevel Converter-type Voltage Source Converter (MMC-VSC) systems. A linearized state-space model of the MMC-VSC system is developed and used to calculate the stability-related frequency-domain attributes. The controller design problem is formulated as an optimization problem. In this paper, the simulated annealing optimization technique is applied to find the proportional-integral (PI) controller parameters that give desired damping for the oscillatory modes and desired values for decaying exponential modes. The efficacy of this method is tested on the electromagnetic transient model of a two-terminal MMC-VSC system on the real-time digital simulators, and the results are provided in this paper. Finally, tuned controller parameters for different ac system strengths are discussed and it is shown that this mathematical model is suitable to tune the PI-controller parameters for MMC-VSC systems connected to strong as well as weak ac networks. [ABSTRACT FROM AUTHOR]

In this paper, a method for numerical simulation of the shape of a ferrofluid under external magnetic fields and the gravitational field is presented. The final shape is determined by an equilibrium condition of energy in a coupled system of electromagnetic fields and ferrofluid in the presence of gravity. The shape of the ferrofluid is captured by using the level set technique. The velocity field is calculated using continuum shape sensitivity analysis based on the material derivative concept. The numerical algorithm is implemented with a standard finite element procedure and tested on a shaping problem of ferrofluid located under an electromagnet. The numerical results showed that the proposed algorithm and numerical techniques are feasible and effective means of calculating ferrofluid shape variation under magnetic fields and the gravitational force. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics of the electromagnetic noise radiated by an external rotor in-wheel motor (IWM) are investigated with the Doppler effect taken into consideration. First, Maxwell stress tensor method is employed to derive electromagnetic forces on the magnet surface. The effect of common current harmonics is also analyzed. Then, a structural model of the rotor is built and modal test is conducted to validate the model. Nodal forces, which are calculated by finite element method, are transferred from the electromagnetic mesh to the structural model for further vibration prediction. Finally, boundary element method is used to calculate the noise radiated by the rotor. In particular, the Doppler effect is considered. The calculated results are validated by the noise test. It is found that the end cap contributes more to the overall noise than the shell, and obvious sound directivity appears in the noise of the IWM. The noise measured perpendicular to the outer end cap is larger than that measured in other directions. In addition, the Doppler effect would induce additional side-frequency components around high-frequency peaks in the external rotor motor. [ABSTRACT FROM PUBLISHER]

It is popular to use moving elements to improve heating uniformity during microwave heating under some situations. However, it is still a challenge to simulate moving elements during microwave heating due to the complexity of mathematical modeling. In this paper, a novel continuous algorithm based on implicit function and level set methods is developed to compute this heating process. By introducing the implicit function and level set methods, the moving region’s properties are set as a function of space coordinate and time, which means that the movement of the elements is represented by the variation of the parameters. In addition, with the coordinate transformation, the coupling process of electromagnetic field and heat transfer in microwave heating can be performed. A 2-D applicator model and a 3-D applicator model with a rotating turntable are used to illustrate the proposed method in detail. Experiments are also conducted to testify the validity of the proposed method. The results obtained by the proposed method are in accordance with those obtained by experiments. Moreover, compared with conventional methods, the proposed method is more accurate and efficient. [ABSTRACT FROM AUTHOR]

Recently, some authors have shown that a DNA molecule produces electromagnetic signals and communicates with other DNA molecules or other molecules. In fact, a DNA acts like a receiver or transmitter of radio waves. In this paper, we suggest a mathematical model for the DNA molecule and use of its communication to cure some diseases like cancer. In this model, first, by using concepts from string theory and M-theory, we calculate the energy of a DNA in terms of interactions between free electrons and bound electrons. We show that when a DNA is damaged, its energy changes and an extra current is produced. This extra current causes the electromagnetic signals of a damaged DNA molecule to be different when compared to the electromagnetic signals of a normal DNA molecule. The electromagnetic signals of a damaged DNA molecule induce an extra current in a normal DNA molecule and lead to its destruction. By sending crafted electromagnetic signals to normal DNA molecules and inducing an opposite current with respect to this extra current, we can prevent the destruction of normal DNA. Finally, we argue that the type of packing of DNA in chromosomes of men and women is different. This causes radiated waves from DNAs of men and women to have opposite signs and cancel the effect of each other in a pair. Using this property, we suggest another mechanism to cancel the effect of extra waves, which are produced by DNAs in cancer cells of a male or a female, by extra waves which are produced by DNAs in similar cells of a female or a male and prevent the progression of the disease. [ABSTRACT FROM AUTHOR]

The present paper discusses a mathematical model of 3D compressible, laminar flame flow, considering the Lorentz force action on the development of fuel combustion in a cylindrical pipe. The combustion process is modelled with Arrhenius kinetics using two exothermic chemical reactions. A system of non-stationary partial differential equations with seven unknown functions is analyzed. For the inviscid 2D axisymmetric swirling flow approximation, the implicit finite difference scheme in time with upwind differences in space and the alternating direction method are used. The results of numerical simulation are confirmed by the results of the experimental study of electromagnetic field effect on the thermo-chemical conversion of a biomass mixture (straw+wood). [ABSTRACT FROM AUTHOR]

SUMMARY To realize fast electromagnetic field analysis, the parallelization technique has been often introduced into the preconditioned Krylov subspace method. When the multicolor ordering is applied to parallelization of forward and backward substitution, the elapsed time of matrix calculation might increase owning to the increment of bandwidth. Therefore, the block-multicolor ordering based on the level structure arising in reverse Cuthill-McKee ordering has been developed. The validity of developed method was demonstrated on the parallelized incomplete-Cholesky-preconditioned conjugate gradient method. In this paper, the parallelization performance of preconditioned minimized residual method based on the three-term recurrence formula of the CG-type (MRTR) method supported by developed ordering is investigated. Furthermore, the affinity of developed ordering or cache-cache elements technique for parallelized forward and backward substitution in Eisenstat's technique is particularly examined. [ABSTRACT FROM AUTHOR]

Solid nano-structures exhibiting fast ion transport (cations moving in anionic crystal structures) are becoming increasingly relevant in industrial applications. However, it is challenging to model their mechanics due to the presence of electromagnetic couplings. In this paper, a mathematical, physical, and computational framework is introduced, for a cation particle moving through an anion sub-lattice structure in the presence of two electromagnetic fields: an external electromagnetic field; and a self-induced electromagnetic field coming from back-reaction phenomena caused by the relative movement of cations with respect to the mentioned structure. Our approach seeks to incorporate magnetic effects, such as magnetic induction and spin of cations, which are not incorporated in other models, mainly due to the intrinsic difficulty of 3D effects. We propose a quantum mechanical formalism based on a Schrödinger-type equation, where a wave function models the behavior of a cation in presence of an external electromagnetic potential, coupled with transient and self-induced electromagnetic effects. To solve the model, a space–time coupled numerical scheme is presented, which allows the possibility of time-evolving electromagnetic effects. The technique uses finite-elements in space and time-marching schemes in time. While a time-explicit marching scheme is used to update the magnetic and electric-potential fields, a time-implicit marching scheme is used to solve the coupled Schrödinger equation. This strategy allows us to update the electromagnetic contributions and wave functions at each time-step. Numerical examples in one and two spatial dimensions (and evolving in time) have been implemented for some meaningful models obtained from nanoionics literature. [ABSTRACT FROM AUTHOR]

This paper describes a two-dimensional (2-D) analytical model to predict the magnetic field distribution in axial-field magnetic gears by using the sub-domain method. The sub-domain method consists in solving the partial differential equations linked to the Maxwell's equations in each rectangular region (magnets, air gaps, and slots) by the separation of variables method. The proposed model is based on a two-dimensional approximation for the magnetic field distribution (mean radius model) i.e. the problem is solved in 2-D Cartesian coordinates. One of the main contributions of the paper concerns the analytic solution of the magnetic field in a slot open on the two sides (space between the ferromagnetic pole-pieces). Moreover, it is shown that the analytical model and the 3-D finite elements simulations follow the same trends in the determination of the optimum values for the geometrical parameters. As the analytical model takes less computational time than 3-D numerical model, it can be used as an effective tool for the first step of design optimization. [ABSTRACT FROM PUBLISHER]

This paper deals with the dynamic analysis for the calculation of the support forces in a rotating elastic rod when subjected to simple types of axial forces. For simplicity the model starts with a linear straight spring and a lumped mass and expands into a distributed system. The analysis shows a shift in the natural frequency of the support forces, due to rotation and additional axial oscillations, these are highly influenced by both the axial and the shear forces, which are induced by the centripetal and Coriolis forces, respectively. Based on this finding, the paper shows that it is not possible to take advantage of the inertial forces and create long-term inertial thrust, even if the rotation is synchronized with the shifted natural frequency. The discussion includes extensions into the electromagnetic realm by comparing the mechanical system with its electrical equivalent. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides theoretical modeling and analysis of applying diamagnetic levitation for nonlinear vibration energy harvesting in detail by first identifying potential merits as well as limitations. Based on a magnetic dipole model, analytical analysis is conducted by providing simplified analytical expressions of restoring forces and electromagnetic damping which are then transformed into a hardening spring model and results in a Duffing equation with strong nonlinearity. In addition, constraints on physical geometry are discussed and derived in the view of practical energy harvester design. More importantly, the derivation and discussion extended to multi-well potential suggest that diamagnetic levitation may enable designing an energy harvester that subject to cross-well chaos with a compact volume and wideband responses. Without mechanical damping in any form, diamagnetic levitation may be considered as a promising mechanism for developing vibration energy harvesters with great performance, and the paper provides a technology push on the possibility. [Copyright &y& Elsevier]

Abstract: The complexity of modern power systems often makes it impractical to model it in its entirety for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of frequency dependent network equivalent (FDNE). The equivalent must be “frequency dependent”, that is match the frequency response of the system it represents, if it is to faithfully represent it. This paper presents a z-domain rational function formulation for developing a FDNE and demonstrates the use of it for the assessment of the steady-state and transient response of the Lower South Island of New Zealand. This paper also shows the accuracy that can be expected from using FDNEs as well as providing a test system for other researchers to benchmark their work against. This is achieved by using a well publicized test system (Lower South Island of New Zealand) the parameters of which are readily available as well as providing complete information of the developed FDNE. [Copyright &y& Elsevier]

This paper is concerned with the scattering and field enhancement of a narrow slit perforated in a slab of perfect conductor. We demonstrate that the enhancement of the electromagnetic field for such a configuration can be induced by either Fabry-Perot type scattering resonances or a certain nonresonant effect in the quasi-static regime. We derive the asymptotic expansions of Fabry-Perot type resonances and quantitatively analyze the field enhancement at the resonant frequencies, for which both the enhancement order and the shapes of resonant modes are precisely characterized. The field enhancement at nonresonant frequencies in the quasi-static regime is also investigated. It is shown that the fast transition of the magnetic field in the slit induces strong electric field enhancement. [ABSTRACT FROM AUTHOR]

Permittivity of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. Many theories and experiments were performed to measure or explain the permittivity characteristics in biological tissue. In this paper, we investigate the permittivity parameter in biological tissues via theoretical and experimental analysis. Firstly, we analyze the permittivity characteristic in tissue by using theories on composite material. Secondly, typical biological tissues, such as blood, fat, liver, and brain, are measured by HP4275A Multi-Frequency LCR Meter within 10 kHz to 10 MHz. Thirdly, experimental results are compared with the Bottcher-Bordewijk model, the Skipetrov equation, and the Maxwell-Gannett theory. From the theoretical perspective, blood and fat are regarded as the composition of liver and brain because of the high permittivity in blood and the opposite in fat. Volume fraction of blood in liver and brain is analyzed theoretically, and the applicability and the limitation of the models are also discussed. These results benefit further study on local biological effects of electromagnetic fields. [ABSTRACT FROM AUTHOR]

Determination of the distribution of electromagnetic energy inside electrically large enclosed spaces is important in many electromagnetic compatibility applications, such as certification of aircraft and equipment shielding enclosures. The field inside such enclosed environments contains a dominant diffuse component due to multiple randomizing reflections from the enclosing surfaces. The power balance technique has been widely applied to the analysis of such problems; however, it is unable to account for the inhomogeneities in the field that arise when the absorption in the walls and contents of the enclosure is significant. In this paper, we show how a diffusion equation approach can be applied to modeling diffuse electromagnetic fields and evaluate its potential for use in electromagnetic compatibility applications. Two canonical examples were investigated: a loaded cavity and two cavities coupled by a large aperture. The predictions of the diffusion model were compared to measurement data and found to be in good agreement. The diffusion model has a very low computational cost compared to other applicable techniques, such as full-wave simulation and ray-tracing, offering the potential for a radical increase in the efficiency of the solution high frequency electromagnetic shielding problems with complex topologies. [ABSTRACT FROM PUBLISHER]

The aim of this paper was to estimate fermentation kinetic parameters to develop a mathematical model of the bioethanol production under magnetic field effect. Thus, a non-structured mathematical model was developed considering three non-lineal kinetic models typically known as Levenspiel, Aiba, Jerusalimsky, which take into account inhibitory effects of the high product concentration on yeasts. The non-lineal differential equations system solution was carried out by MatLab software using the Runge-Kutta fourth-order multivariable method. This method was improved through a replication scheme coupled with Newton-Raphson method modified with a damping Broyden parameter. Experimental data on substrate consumption, biomass formation and ethanol production were collected at magnetic field intensities (H) of 414, 796 and 1216 A/cm during 16 h of fermentation. Consequently, the adjusted model for biomass, consumed substrate and bioethanol produced allowed us to correlate fermentation kinetic parameters with the magnetic field. The best result was observed when Jerusalimsky model modified with a magnetic field parameter was considered, because the RMSD order and R-square correlation coefficient were around 10−3 and higher than 0.95, respectively. These results are important to understand the phenomenological behavior of this unconventional bioprocess and be helpful to further sensibility analysis and scale up of the bioethanol production assisted by electromagnetic field. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Metamaterials with tunable negative permeability are proposed and investigated theoretically in this paper. First, the model of the dielectric bilayer sphere embedded in the dielectric substrate is put forward. Second, expressions of the electromagnetic fields in the model are derived based on the Mie scattering theory, and the general formula for the effective permeability of the model is deduced via the Maxwell-Garnett theory, which is further verified through the simulation results. Finally, the tunable bandwidth of the negative permeability of the metamaterials changing with the geometrical parameters is investigated based on the full-wave simulations, and the relative mechanisms are also discussed. It is believed that the results would be helpful for the practical applications of the metamaterials, and the metamaterials with tunable negative permeability proposed in the paper would facilitate the constructions of the left-handed materials in some degree. [ABSTRACT FROM PUBLISHER]

This paper deals with some aspects of formulation and implementation of a broadband algorithm with build-in analysis of some dispersive media. The construction of the finite element method (FEM) based on direct integration of Maxwell's equations and solution of some additional convolution integrals is presented. The broadband, fractional model of permittivity is approximated by a set of some relaxation sub-models. The properties of the 3D time-dependent formulation of the FEM algorithm are determined using a benchmark problem with the Cole-Cole and the Davidson-Cole models. Several issues associated with the implementation and some constraints of the broadband finite element algorithm are presented. [ABSTRACT FROM AUTHOR]

The paper deals with the interaction between electromagnetic and hydrodynamic field of electromagnetic thruster. The mathematical model of the interaction defines the constant ruler of MHD interaction. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to provide an efficient computational model for fast and accurate calculation of electromagnetically induced vibrations in electrical machines. Although a three-phase permanent-magnet synchronous machine has been used in this paper, the same methodology can be extended to other types of electric machinery. A brief comparison between the different methods for structural analysis in electrical machines is introduced. The method proposed in this paper uses finite-element analysis in order to extract the impulse responses that are used in calculating the vibration. A field reconstruction method is used for the electromagnetic field analysis. [ABSTRACT FROM PUBLISHER]

This paper presents an exhaustive simulation study performed to validate the adequacy of the equivalencing method promoted by the National Renewable Energy Laboratory for modeling wind power plants by single- and multiple-machine equivalents. The main simulation results are presented for a number of steady state and transient wind turbine generator operating conditions following various faults and a typical low-voltage ride through. The impact of protection systems such as the crowbar is also taken into account. The aggregation technique has shown to be adequate for load flow, stability, and electromagnetic transient studies with limitations, as presented in the paper. [ABSTRACT FROM AUTHOR]

This contribution is a review paper, concerning mainly the research work made by the authors, about the numerical modeling, in the frequency domain, of both surface and bulk plasmon oscillations induced in metallic nanoparticles with arbitrary shapes by an external electromagnetic field. Surface plasmons are governed by a local constitutive relation, whereas bulk plasmons are governed by a constitutive relation that is expressed by a partial differential equation. The electromagnetic field scattered by the nanoparticles is evaluated using an integral formulation. In nanoparticles with maximum linear dimensions much smaller than the vacuum wavelength the plasmon dynamic may be studied approximately by using the electro quasi-stationary approximation of the Maxwell equations. The paper discusses both a full-wave integral formulation, where the unknown is the induced current density, and an electro quasi-stationary integral formulation, where the unknown is the surface charge density. [ABSTRACT FROM AUTHOR]

The evaluation of the lightning performance of overhead lines requires, mainly for distribution lines, the calculation of the voltages induced by nearby lightning strokes hitting the ground. Generally, when calculating lightning-induced voltages using the time-domain approach and the TEM assumption, the most time-consuming stage is the calculation of the source terms of the coupling equations, which means, in turn, the electromagnetic field radiated by the lightning channel. Hence, simplified approaches are still desirable in order to save computational time. Analytical solution of the lighting-originated electric- and magnetic field is available in literature for the case of an ideal transmission-line (TL) return-stroke model with channel-base current having a stepwise waveshape. This paper describes an analytical approach that applies to the case of a general waveshape of the channel-base current, based on the piecewise straight-line approximation, in cylindrical coordinates, which is functional when using the TL return-stroke current model and the Agrawal et al. coupling model. This paper reports the exact solution for the case of trapezoidal waveshape of the current at the base of the channel and the analytical solution for the case of piecewise linear waveform. [ABSTRACT FROM AUTHOR]

This paper deals with the use of the integrated circuit electromagnetic model (ICEM) to analyze, predict, and optimize autocompatibility and electromagnetic emission at chip and system level. ICEM is currently under standardization process (IEC62014- 3). The basic ICEM architecture is composed of a power distribution network model and an internal current source modeling digital activity. Such an approach enables the description of any kind of digital or mixed-signal design. This model is useful either for the IC manufacturer or the system manufacturer. The power distribution network of a printed circuit board (PCB) can be optimized using this model by choosing the number and the right values of decoupling capacitors as well as the size of power planes. The IC manufacturer may check out the autocompatibility of an IC and determine the number of power pins as well as the package to be used. As an example, jitter analysis of an integrated phase-locked-loop can be performed using ICEM. This paper demonstrates that this jitter can be predicted by simulation and that corrective solutions can be provided and checked out before implementation. [ABSTRACT FROM AUTHOR]

This paper analyses the possibility to computationally settle consistency of field problems, especially those arising from electromagnetic modelling: the electromagnetic theory is expressed in field-oriented concepts, which allow for formulation of boundary value problems with no solution at all or infinitely many solutions. This possibility of such inconsistent problems decreases the productivity of electromagnetic design software. This paper relates the consistency question to topological aspects of the model domain, and proposes a scheme for routine computation of the relevant topological aspects of electromagnetic models. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents a field-circuit-coupled method to investigate differences between intrinsic and measured permittiveties for a Mn-Zn ferrite. Electric and magnetic fields in a flat cylindrical ferrite, which is used here to construct a ferrite capacitor, are solved analytically. Then, complex power supplied to the capacitor is calculated. On the basis of the complex power, parametears in an equivalent circuit for the ferrite capacitor are extracted. The paper examines the validity of the developed mathematical model. Numerical results show that for a ferrite with high permeabilities, measured permittivities follow intrinsic values well at low frequency but fail to embody the intrinsic values when the frequency runs above several hundred kilohertz. Numerical results also demonstrate that the dimensions of the sample under investigation play a role in measurement errors. The larger the radius of the cylindrical ferrite is, the higher the errors are. Correction curves are generated, from which the measured permittivities can be corrected to reflect the intrinsic values. [ABSTRACT FROM AUTHOR]

The computation of electromagnetic (EM) fields for 1-Dlayered earth model requires evaluation of Hankel transform. In this paper we propose a stable algorithm for the first time that is quite accurate and fast for numerical evaluation of the Hankel transform using Sine-Cosine wavelets arising in seismology. We have projected an approach depending on separating the integrand rf ( r ) J ν ( pr ) into two components; the slowly varying components rf ( r ) and the rapidly oscillating component J ν ( pr ). Then either rf ( r ) is expanded into wavelet series using Sine-Cosine wavelets orthonormal basis and truncating the series at an optimal level or approximating rf ( r ) by a quadratic over the subinterval using the Filon quadrature philosophy. The solutions obtained by proposed Sine-Cosine wavelet method applied on 5 test functions indicate that the approach is easy to implement and computationally very attractive. We have supported a new efficient and stable technique based on compactly supported orthonormal wavelet bases. [ABSTRACT FROM AUTHOR]

The paper presents analysis of surface induction hardening of a cylindrical element made of steel 38Mn6. The mathematical model of the non-stationary process is elaborated. Calculations of coupled electromagnetic and temperature fields are provided by means of the Flux 2D software. Computations are compared with the measurements realized at the laboratory stand located in the Silesian University of Technology. The expected hardness distribution within the surface layer is noticed. [ABSTRACT FROM AUTHOR]

Solid dielectrics have been widely investigated as potential attractive candidates in compact portable pulsed-power systems. Slow-wave structure with good dispersion characteristics and broad transmission band can be used to increase the pulse duration while the size of pulse-forming line (PFL) decreases. In this paper, we present two different slow-wave structures, the tape helix for coaxial-line and the meander-line structure for the planar line, to increase the pulse duration of solid PFLs based on dispersion analysis. At first, the characteristic impedances, electric length, and dispersion curve of the PFL with the slow-wave structure are calculated by the electromagnetic dispersion theory. Based on the theoretical calculations, the PFLs are designed and simulated by the electromagnetic field tool. Finally, some test results on the PFLs are introduced. Currently, both the Al2O3 ( \varepsilon r= 9.3 ) helical PFL and the glass–ceramic ( \varepsilon r = 225 ) meander-line PFL can deliver a pulsewith 50-ns width, of which the dimension is \phi ~67~\mathrm mm \times 305 mm and 95~\mathrm mm \times 95~\mathrm mm\times 4 mm, respectively. [ABSTRACT FROM PUBLISHER]

The aim of this paper is to highlight the capabilities of a new hybrid analytical modeling (HAM) approach for the analysis and design of various electromagnetic structures. After an introduction, where the aim of the development of this modeling approach is presented, the modeling approach is described. The new HAM is based on a strong coupling of the magnetic equivalent circuits method and analytical models (AMs). The AM, based on the formal solution of Maxwell’s equations, is established thanks to the separation of variables method. The HAM is applied to different permanent magnet electric machine structures, and the results are validated extensively by comparison with the finite-element analyses. [ABSTRACT FROM AUTHOR]

Numerical techniques for calculating electromagnetic fields within three-dimensional surfaces are computationally intensive. Therefore, this paper presents the application of a mode-matching technique developed for analyzing electromagnetic scattering from periodic comb surfaces illuminated by a plane wave. A set of linear equations has been developed to calculate mode coefficients of the field distribution for both E- and H-polarized incident waves. Analysis is performed for two cases where the comb thickness is either infinitely thin or of a finite thickness. The technique is shown to accurately predict both field intensities within the near-field of the periodic surface and far-field scattering patterns. Results are compared to those obtained using the finite integration techniques (FIT) implemented in CST Microwave Studio. Furthermore, numerical results are compared to measurements of an aluminum prototype. Additional far-field scattering measurements using a bi-static system provide additional confidence in CST simulations and the mode-matching methods presented here. [ABSTRACT FROM PUBLISHER]

Most studies presented to date in the use of the marine controlled source electromagnetic (CSEM) method to detect hydrocarbons analyze the homogeneous reservoir models of isotropic or anisotropic resistivity. In the present paper, we use 3D vector finite element modeling to calculate the electromagnetic response from various inhomogeneous reservoir models of a complex structure. Also, we study the electromagnetic field propagation inside the homogeneous and inhomogeneous 3D reservoirs, as well as the problem of equivalence of inhomogeneous and homogeneous reservoirs. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, representations of a perfectly conducting thin wire and an imperfectly conducting medium in the transmission line modeling (TLM) calculation are briefly explained. Then, the method is applied to analyzing surge responses of a vertical parallelepiped grounding electrode and a square-loop grounding electrode. Surge responses calculated using the TLM method agree reasonably well with the corresponding responses measured and calculated using the finite-difference time-domain method. It is probably the first time that surge responses of grounding electrodes have been analyzed reasonably accurately using the TLM method. [ABSTRACT FROM AUTHOR]

Electromagnetic method to measure water flow has been known for nearly 180 years. This paper presents how the method has undergone development and describes in detail the most common electromagnetic flowmeters used for open channels. It also presents specific methods of signal processing used in this type of flowmeters. The analysis is associated directly with the relevant types of induced magnetic field. Some of the analyzed types of magnetic fields considered are sine waves and bipolar rectangular fields. The concept of low-energy electromagnetic flow meter was introduced as part of deliberations concerning current development trends. [ABSTRACT FROM AUTHOR]

Due to the various physical mechanisms of interaction between a worker's body and the electromagnetic field at various frequencies, the principles of numerical simulations have been discussed for three areas of worker exposure: to low frequency magnetic field, to low and intermediate frequency electric field and to radiofrequency electromagnetic field. This paper presents the identified difficulties in applying numerical simulations to evaluate physical estimators of direct and indirect effects of exposure to electromagnetic fields at various frequencies. Exposure of workers operating a plastic sealer have been taken as an example scenario of electromagnetic field exposure at the workplace for discussion of those difficulties in applying numerical simulations. The following difficulties in reliable numerical simulations of workers' exposure to the electromagnetic field have been considered: workers' body models (posture, dimensions, shape and grounding conditions), working environment models (objects most influencing electromagnetic field distribution) and an analysis of parameters for which exposure limitations are specified in international guidelines and standards. [ABSTRACT FROM AUTHOR]