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Electrical properties of magnetic material are mainly defined by producers by means of magnetic characteristics H = ƒ(B) and loss characteristics p = ƒ(B), both for industry frequency, i.e. 50 or 60Hz. The curves defined in this manner are not compatible with those of higher frequency, i.e. far above 50Hz. The latter cases are of great importance when dealing with power electronics systems.

The problem of generating currents of neural cells in human brain has been recently investigated, as it is believed to substitute electroconvulsive therapy (ECT) having the same therapeutic effects but realized in much safer way (painless, non‐invasive and without motor seizure). The magnetic stimulation (transcranial magnetic stimulation — TMS) uses low frequency pulse, from a few cycles per second to a few of tens, magnetic field in order to induce eddy currents in the deeper layer of brain structure.

The aim of this paper is to investigate the coupling model which describes the relationship between the electromagnetic (EM) field emitted by a field source, in this case the mobile phone, and the interfering voltage at a cardiac pacemaker which is digitally implanted into the human body model.

The research was carried out using two kinds of numerical phantoms with various configurations, i.e. the mobile placed in front of a trunk and the mobile placed near the human ear (totally 12 configurations). Moreover, the simplified homogeneous human model with numerically implanted cardiac pacemaker is considered (two configurations). The simulations are carried out using the finite difference time domain method according to international standards.

From the investigation it was found that the interfering voltage at the cardiac pacemaker (for each of the considered models) was much smaller than the one proposed by IEC standard. A practical conclusion that can be drawn is that the highest interfering voltages occur when the mobile is in a vertical position.

The analysis was limited to the cardiac pacemaker with a unipolar electrode and could be carried out for other types of pacemakers.

The evaluations such as those presented should be useful in the development of protection standards of human exposure to EM field with respect to humans with implants such as cardiac pacemakers. Furthermore, such a modeling allows for the evaluation of potential EM interference prior to an implantation of implants.

Such a detailed analysis of a coupling model considering various configurations of mobile phone position to a human model has so far never been carried out.

In 1993 the 200th anniversary of George Green, a great physicist and mathematician's, birth was celebrated. His contribution to world's science is beyond the question. This can best be seen in the frequency of mentioning his name and quoting his works in other physicists' and mathematicians' works. Some of historians of science and researchers are deeply convinced that George Green together with Maxwell originated modern electromagnetism. George Green is also famous for his inventions as far as light, stress and accoustic theories are concerned but electromagnetism ows him most of all. Indeed, none of those who have ever dealt with mathematical electromagnetism will question George Green's part and position. In nearly each paper referring to it, Green's function or Green's identities are the terms that are mentioned or quoted. Without these notions contemporary numerical techniques such as finite element method (first Green's identity) or boundary element method (second Green's identity) or integral methods (Green's function) are hard to imagine.

The interactions of electromagnetic fields and biological structures are of great interest both from medical and technological points of view. The medical aspect is well‐known even in archaic medicine while bio‐electrotechnology is being developed just at recent time. Especially it is readily seen when dealing with electric field and its influence on living cells. Biologists and biochemists are mainly interested in the voltage induced in the cell membrane (transmembrane voltage). This gives the information about forces acting on membrane which cause the phenomenon called dielectrophoresis. The other phenomenon which joins electromagnetic field and biological structures is electroporesity when the pores in a membrane are caused by electric field. It seems that the latter case requires carefully carried calculations since the transmembrane voltage decides on the phenomenon. The paper, however, does not aim at very biological effect; our goal is to show how the electric field in the cell and the membrane voltage should be calculated. It should be stressed that the research in bio‐electromagnetism is on very initial step as concerns the calculation methods. This results from two facts: the first is that so far there were no links between people working on computational electromagnetism and biologists and the second comes from the complex nature of biological structures which cannot be modelled as easy as it is with technical products. Thus, the paper is aiming at showing how the cell is modelled and what the main dependencies which govern electromagnetic phenomena are. This may be considered as an introductory step to further activity in this area.

This paper seeks to develop 3D finite element methods for the electromagnetic field calculation in electrical machines and to present the discrete methods of winding description.

The 3D finite element models of electrical machine windings are considered. Attention is paid to the windings with stranded conductors. The finite element equations are considered as the equations of magnetic networks. The formulation of matrix that transforms winding currents into the field sources is discussed. This matrix is also used in the calculations of flux linkages. In the proposed method, the winding loops are replaced by a set of plane loops. The field sources are defined by the numbers of these loops around the element edges and loops associated with element facets.

The presented description is the 3D finite element representation of MMF description used in the classical models of electrical machines. The advantage of the proposed approach is that the source description can be successfully applied in the FE method using single scalar potential. In addition, the presented approach guarantees a good convergence of ICCG procedure of solving edge element equations for ungauged formulation using magnetic vector potential.

The applied analogies between the finite element formulation and the equivalent magnetic network models help to formulate an efficient method of field source description. The developed method allows one to apply single magnetic scalar potential in the 3D finite element analysis of electrical machines.

The purpose of this paper is to use numerical methods and modelling to estimate the effect of a passive, metallic (conducting) implant on eddy currents distribution in a human knee model. There exists a concern among wearers of such implants that they alter electromagnetic field (eddy currents) significantly and there is a need for standardization of that problem.

The numerical model of a human knee has been built on the base of Visual Human Project and electromagnetic field calculations were carried out using Meep FDTD engine. In total, two scenarios have been considered: the knee model with and without a metallic implant. The knee implant model has been prepared as the knee model with overestimated electrical parameters of bone tissues by titanium metal. Alternating eddy current distribution has then been evaluated for both models using FDTD low frequency algorithm.

The highest values of eddy currents occurred on the interface between skin and muscle tissues when the model without an implant is considered. However, when the bone tissues have been replaced with titanium metal, the highest values have occurred in the implant (about 100 times higher than the previous one). This means that an implant can be heated by external electromagnetic fields and that the location of the highest values of eddy currents can be shifted to the proximity of the implant. Moreover, one should realize that in this model the implant is like a knee bone with all anatomical details. It has emerged from this that the implant's shape and size are essential when evaluating its effect on eddy currents distribution.

The interaction of electromagnetic field with implants should be generally further investigated, at least for the presumable worst cases. Such investigation has already been done by some researches but they have been devoted to radio frequencies. The authors believe that the presented research will be helpful in the standardization process, when talking about low frequency electromagnetic field.

The presented methodology can be used in the development of computer aid diagnosis systems. Overestimation of electrical parameters of some parts of the model allows us to predict the distribution of electromagnetic field in the model under investigation very quickly. The results presented in the paper can be used during the standardization process.

Deals with the problems of interactions between the electromagnetic field and the human brain. In particular, the problem of eddy currents in brain tissue induced for medical purposes is discussed. The mathematical modelling of the phenomenon is presented.

The paper aims to clarify the method/methodology of establishing a computer model of the electromagnetic therapy connected with some knee joint problems. Two cases are considered: the arthritis of the knee and the fracture of bone. In both cases the analysis of eddy current distribution in the knee is made. It gives results which can be helpful in the planning of treatment. The paper presents the exemplary results of eddy current distribution inside a bone. A short discussion on the safety aspect of magnetotherapy has been carried out.

In order to calculate the eddy current distribution in human knee joint the low frequency finite‐difference time‐domain algorithm has been applied. The numerical model of the leg was based on US Air Force Research Laboratory data and the electrical properties of tissues were modeled using 4‐Cole‐Cole approximation with parameters taken from Gabriels.

The paper presents the general methodology which can be used in magnetotherapy to estimate a magnetic flux density of stimulators and value of current density inside the knee joint. Both factors mentioned above can be helpful in therapeutical processes, i.e. in magnetoteraphy.

The eddy current distribution is limited to the presented model and it is obvious it can be different for another one as it is shown in the paper but it is also shown that the biggest value of eddy current density is just in the vicinity of the joint, so it can help in a therapeutical process.

The methodology of estimating the values of current density and magnetic flux density can be used by physiologists and doctors to determine the value of current density which gives therapeutical effect.

The efficient application of low frequency finite‐difference time‐domain algorithm to the electromagnetic therapy connected with some knee joint problems has been shown and the general methodology has been conducted.

The purpose of this paper is to present the performance characteristics analysis of a new type axial flux permanent magnet (AFPM) machine according to the geometric structure of rotor such as permanent magnet dimension, the air‐gap length and so on.

The 3D finite element method (FEM) is used to analyse electromagnetic fields with the aid of an ANSYS software package. The FEM is based on the magnetic vector potential and the governing equation can be obtained from the Maxwell equation. Using the dynamometer system, the characteristics of the AFPM machine were estimated according to load torque.

The AFPM machine characteristics with static torque, cogging torque and flux density according to rotor geometric dimensions are analyzed using a 3D FEM software package. And then, the prototype of an AFPM machine and several rotors with different PM structure are manufactured and tested. Resulting from the experiment, the characteristics such as EMF waveform, speed and efficiency curves according to load torque, and efficiency curves according to PM thickness, are obtained. The measured performance results verified the overhang effects and improved the efficiency of the motor.

The paper proposes a new type AFPM machine structure with T‐shape teeth and laminated back yoke and two types of rotor with fan‐shaped permanent magnets. It presents the results of characteristics of the proposed AFPM machine throughout the simulation and experiment.