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Previously we have succeeded in exploiting a new high sensibility eddy current testing (ECT) sensor called the infinite (∞) coil. Operating principle of this ∞ coil is that two adjacent coils constructing the north and south poles alternatively set a zero magnetic potential region and keep the same situation when eddy currents are flowing along the paths in parallel to the exciting coils. If the eddy currents could not flow the paths in parallel to the exciting coil on the test specimen, then a zero magnetic potential region between the two exciting coil moves toward the other position. This means that a sensing coil located at a mid position of two exciting coil is possible to detect the disturbed magnetic fields, i.e., the defect in the test specimen could be detected from the sensing coil signal. In the present paper, consideration of the practical flat/film ∞ coil design leads to an employment of the two rectangular shape exciting coils. Practical experiments and 3D FEM simulations verify the validity of our practical design policy of the flat/film∞ coil. [ABSTRACT FROM AUTHOR]

Appearance of the new generation nano-ferro fluid materials dramatically improves operational characteristics of electromagnetic systems and devices. In this work new performance of solenoid type electromagnetic actuator with nano-ferrofluid is investigated and analyzed. Theoretical approach based on 3D multiphysics model of the actuator is developed for fields, processes and phenomena analysis as well as for determination of actuator operational characteristics and parameters. The model couples together electromagnetic field analysis, electric circuit analysis, fluid dynamics analysis and mechanical movement analysis. Transient mode of switching on the electromagnetic actuator is modeled. Measurement system for experimental determination of static and dynamic characteristics of the electromagnetic actuator with ferro fluid is built. Operational electromagnetic characteristics of the actuator are obtained and compared with and without ferro fluid presence in the working gap. Measured results are presented, analyzed and compared with those obtained by developed theoretical model. The developed theoretical and experimental models and investigation approaches could be used in design, optimization and investigation of new effective electromagnetic actuators and devices. [ABSTRACT FROM AUTHOR]

Electromagnetic field distribution in biological structures is a challenging multidisciplinary problem that may offer many new opportunities for precise medical diagnosis and therapy due to modern scientific approaches. Investigation of electromagnetic fields, processes and phenomena is significantly improved by new highly precise computational models and field reconstruction strategies. In this work, method of magnetic fluid hyperthermia for breast cancer therapy is modeled and investigated. Coupled field modeling of ferrofluid transport and heating in tumor tissue is presented. A 3D electromagnetic - thermal - fluid dynamic finite element method model is developed. The model uses anatomically precise multilevel geometrical model of human with real cancer sample acquired by surgical procedure. Thermal field results are verified by infrared thermograph imaging. [ABSTRACT FROM AUTHOR]

Electromagnetic field distribution in biological structures is challenging multidisciplinary problem which may offer many new opportunities for medical diagnosis and therapy due to modern scientific approaches. Investigation of electromagnetic fields, processes and phenomena is significantly improved by new highly precise computational models and field reconstruction strategies. These problems can be broadly divided into two main topics. First is the field of biomagnetic or bioelectric fields produced naturally into the biological structures. Second wide topic contains all problems of interaction of outer electromagnetic fields with biological structures. In this paper some new approaches and results in determination of bioelectromagnetic fields and bioelectromagnetic interaction are presented. These researches are focused exclusively in the area of inverse source and material properties reconstruction in inaccessible for direct measurements regions. Results from computational techniques are presented and discussed. [ABSTRACT FROM AUTHOR]

In this paper a method for characterization of live tissue electromagnetic properties is proposed. The method combines data, acquired by experimental computer system for bio-impedance measurements, and image data obtained by infrared camera. The data from impedance analyzer and from infrared camera are collected simultaneously for a given time period. The impedance data are associated with infrared image data for electromagnetic properties determination. The method developed is applied to evaluate the electromagnetic properties of biological tissues. The proposed method is applicable for local electric properties determination in inhomogeneous samples with random form. [ABSTRACT FROM AUTHOR]

Computer modeling of electromagnetic fields distributed in biological structures is of paramount importance for investigations of processes and phenomena during medical diagnosis and therapy. Here a complete process methodology of electromagnetic model building is presented. The process contains a method for automatic 3D model building, electromagnetic properties measurement system and electromagnetic field computational algorithm based on Finite element method (FEM). Recent achievements of the FEM give possibilities to model fully three-dimensional, nonlinear, inhomogeneous, or anisotropy multi-tissue, and multi-joint systems of biological structures. Implementation of the developed methodology to investigation of the electromagnetic field distributions in human body tissues during magnetic stimulation demonstrates capabilities to solve such complex problems. [ABSTRACT FROM AUTHOR]

Electromagnetic devices used for medical diagnosis and therapy need high power to produce high magnetic fields, which makes such devices considerable energy consumers. Optimization of the fields and processes during energy interaction between electromagnetic devices and nonlinear, inhomogeneous and complex biological structures opens up the possibility to develop high quality, energy saving electro-medical devices. The aim of the project is to reduce significantly electrical energy consumption, allowing at the same time for precise and effective medical diagnosis and therapy. This will be achieved by optimization of the energy interaction between electromagnetic devices and biological structures. The study of the factors and conditions for increasing energy efficiency of these electromagnetic interactions is of great importance. Mathematical models, algorithms and approaches for the analysis and synthesis of fields and processes will be developed and experimentally verified. Up-to-date methods for optimization, visualization, data manipulation, signal and image processing will be used for the computer modeling. For the analysis and synthesis of electromagnetic fields we will use the three-dimensional finite element method. For the experiments, computer-controlled setups will be developed with a possibility for continuous control and recording of data during the experiment. The proposed approaches will be applied for optimization of energy interactions between biological structures and electromagnetic devices. The expected outcomes of this project are new energy efficient, compact and high quality devices for wide applications in hospitals and medical centers. [ABSTRACT FROM AUTHOR]

A method of information processings based on the classical field theory is outlined to derive the modal-wavelet transform (MWT) as a wavelet-like orthonormal transform. The theoretical background and application of MWT are described. The bases of MWT are derived from modal analysis of the potential field equations. Namely, a principal idea of MWT is that a numerical data set is regarded as a set of the field potentials or source densities. A modal matrix, constituting characteristic vectors, derived from the discretized field equations enables us to carry out an orthonormal transform inasmuch as the same way as those of conventional discrete wavelets. MWT is based on this data modeling to provide multiresolution analysis in an efficient manner. Three-dimensional MWT demonstrates a classification of a weather satellite infrared animation into background and cloud-moving frame images. [ABSTRACT FROM AUTHOR]

The purpose of this article is to apply an inverse approach for image reconstruction during electromagnetic field visualization. The reconstruction of the images is formulated as an inverse problem. For the image color model, the Poisson equation with open boundary condition is imposed. The color source densities have been evaluated from the color distributions for electromagnetic field data set. The Generalized Vector Sampled Pattern Matching method is applied to solve an ill posed linear system of equations for the corresponding inverse problem. The new color distributions are generated and visualized using the obtained color source densities. With the proposed inverse approach the dark parts of the images can be reduced or completely removed. This article collects several examples for electromagnetic field visualization of the most commonly used sensor coil. [ABSTRACT FROM AUTHOR]

Presents information on a study which described a neural network inversion approach to electromagnetic device design problem. Inverse problem of device design; Application of the method; Conclusions.

This paper presents a two-dimensional FEM (Finite Element Method) modeling and simulation of a surface acoustic wave (SAW) resonator based on a layered Pt/AlN/Sapphire structure. Such structure that exploits the electromechanical coupling of piezoelectric film is of high interest for harsh environments. By harsh environment we mean any environment that could hinder the operation of the device. Hardness can come from a variety of sources, and examples include the following: High pressure, High temperature, Shock/high vibration, Radiation, Harsh chemicals, etc. As part of this work, we are looking for high temperature sensor applications and only operating drifts due to temperature will be studied. SAW resonator is made from piezoelectric thin film Aluminum Nitride (AlN) layer on Sapphire substrate. Modal analysis is used to determine the eigen mode and the eigenfrequency of the system and the study of the frequency domain is used to determine the response of the model under influence of a harmonic excitation for one or more frequencies. In the FEM modeling, various parameters of the surface waves in the films, such as the surface velocity, the displacement of the piezoelectric thin film, the electrical potential, the electromechanical coefficient (k2), and the quality factor (Q) were studied. A comparative study between modeled and experimental curves showed a good agreement and allowed to validate our simulation method. Finally, a FEM study of the influence of normalized thickness of AlN thin film on resonator performances was carried out and compared with theorical results of literature. [ABSTRACT FROM AUTHOR]