International Journal of Applied Electromagnetics and Mechanics - Volume 15, issue 1-4

Authors: Mukhopadhyay, S.C. | Yamada, S. | Iwahara, M.

Article Type: Research Article

Abstract: This paper has investigated the possibility of applying nondestructive evaluation technique for finding the defects in electroplated materials. Planar meander and mesh type magnetic sensors have been considered and their relative performance have been compared based on a single criterion that the effective area of the material surface covered by each type of sensor is same.

DOI: 10.3233/JAE-2002-461

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 323-329, 2002

Authors: Kohno, H. | Watanabe, K. | Nomura, Y. | Saito, M.

Article Type: Research Article

Abstract: The component of ITER facing directly to plasma is called the first wall. The first wall is composed of DSCu/SS316 HIP bonded structure. In addition to residual stress due to the HIP bonding process the electromagnetic force is loaded on the first wall during plasma disruption. In this study, we assume an initial crack in the first wall. Stress induced by the electromagnetic force at the crack tip is estimated by finite element method taking the …residual stress into consideration. From a viewpoint of fracture mechanics, stress intensity factor K is evaluated to make sure the structural integrity of the DSCu/SS316 HIP bonded structure. As a result of analyses, the stress intensity factor K is not so large for all of the assumed cracks. Therefore, there is no possibility of fracture due to the crack growth during the lifetime of the first wall. Show more

DOI: 10.3233/JAE-2002-469

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 331-336, 2002

Authors: Endo, Hisashi | Saito, Yoshifuru

Article Type: Research Article

Abstract: This paper introduces a novel approach of visualization for electromagnetic fields. Our approach is one of the image analysis methodologies based on the classical field theory, which has versatile capability for image processing, compressing, visualizing, identifying, and animating. A key idea is that each of the pixels representing a digital image is regarded as a kind of potentials in vector fields. Gradient or curl operation of the vector calculus to the image data yields image field …vector distribution. Any kinds of images can be represented by well-known partial differential equations. The Poisson and Helmholtz types of equations are possible to represent the static and dynamic images, respectively. In this paper, visualized electromagnetic field images are analyzed based on our image differential equations. The image Poisson equation is possible to reconstruct the original electromagnetic fields with high spatial resolution. The image Helmholtz equation enables us extr action of the parameters characterizing the electromagnetic phenomena. Show more

DOI: 10.3233/JAE-2002-485

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 337-342, 2002

Authors: Senoo, Isamu | Saito, Yoshifuru | Hayano, Seiji

Article Type: Research Article

Abstract: We have been proposing the image processing methodology where the human voice signals are transformed into the three-dimensional image data by means of the three-dimensional Lissajous diagram [1]. In this paper, we apply the image cognition technology to the cognition of the magnetic sensor signals. At first, the time domain signals are converted into the three-dimensional images, which construct the database system. Secondly, when we measure a time domain signal, this signal is also converted into …a three-dimensional image. This three-dimensional image becomes an input vector of a least squares means. Least squares solution gives a composite signal as a linearly combined database signals. Extracting the most dominant term from the least squares solution reveals the cognized signal. Thus, we have succeeded in the time domain magnetic sensor signal cognition by means of the image cognitive technology [2]. Show more

DOI: 10.3233/JAE-2002-475

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 343-347, 2002

Authors: Shigeta, Yukiyasu | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: In the present paper, we propose a method of analysis for the magnetic sensor signals. Based on the physical characteristic value such as a time constant of the electric circuits, our methodology tries to work out an equivalent characteristic value reflecting the physical property of the target metallic material [1,2,3]. Our smart magnetic sensor developing is to recognize a datum from the signal database. This is applied to the space domain signal cognition. As a result, …this paper reports that the equivalent characteristic value is an extremely useful quantity in order to examine the physical nature of the target. Show more

DOI: 10.3233/JAE-2002-479

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 349-352, 2002

Authors: Watazawa, Yasuyuki | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: Any of the numerical methods for electromagnetic field analysis essentially require a subdivision of a problem region. By notifying this subdivision, we have previously proposed a new methodology by applying the analytical solution to each of the discretized parts. The first trial of this semi-analytical electromagnetic filed computational methodology has made it possible to simulate the complex electromagnetic field distributions not obtainable by the conventional numerical schemes, such as finite and boundary …elements means. However, our semi-analytical method encounters some difficulty when analyzing the high frequency electromagnetic field distributions because of the displacement currents.In the present paper, we propose a new semi-analytical approach taking the displacement currents into account to overcome this difficulty. Show more

DOI: 10.3233/JAE-2002-473

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 353-357, 2002

Authors: Kato, Chieko | Endo, Hisashi | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: A new computer-aided method, based on Saito's Fourier-wavelet theory, is used to extract the facial expressions that appear and disappear in less than one-fifth of a second, i.e. expressions that reveal the true emotions of a human being. The new method consists of two major steps. The first step is the application of the Fourier transform to reduce the spatial phase differences between the reference and test images. The second is the application of the wavelet …transform to extract the local discontinuous differences. This method is applied to the moving images in the interview scene. Using this method, the difference between the two facial expressions has been extracted, even though both images differ in their size and reference position. Show more

DOI: 10.3233/JAE-2002-481

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 359-364, 2002

Authors: Ema, Akira | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: In the present paper, we propose the methodologies in order to realize the desired magnetic field distributions by using single-sided exciting coils. As a result, it is revealed that a combination of the least squares and the generalized vector sampled pattern matching method suggests the practically realizable exciting coil layout.

DOI: 10.3233/JAE-2002-478

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 365-370, 2002

Authors: Morohoshi, Noriko | Endo, Hisashi | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: When reading a novel by EKUNI Kaori, reader's world in the brain has been clarified by means of the discrete wavelet analysis. According to the analysis, reader's world in the brain has been classified into two layers. One is the world in the book and the other is the existing real world. Major target of this paper is to visualize the transition states between two layers. As a result of our analysis, it has been revealed that the wavelet multi-resolution …analysis has made it possible to visualize the transition states as well as to clarify the composing methodology of the novel. Show more

DOI: 10.3233/JAE-2002-480

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 371-375, 2002

Authors: Naruta, T. | Endo, H. | Hayano, S. | Saito, Y.

Article Type: Research Article

Abstract: In order to design an optimal planar inductor, this paper carries out several axisymmetrical magnetic field simulations fully taking the magnetic hysteretic properties of ferromagnetic core materials as well as open boundary condition into account. Finite element method is applied to evaluating the magnetic fields, reactive and dissipative energies in a planar inductor. Because of the nature of magnetic fields, it is essentially taken into account the open boundary effects to evaluate the exact characteristics of …planar inductor. Since the finite elements is one of the methodologies to solving for the partial differential equations, and then it has been difficult to take the open boundary effects into account. However, this paper removes this difficulty by employing the strategic dual image (SDI, in short) method [1,2]. Another difficulty is caused by the hysteretic magnetization characteristics of magnetic core materials. Applying the Chua type magnetization model to represent the hysteretic property also removes this difficulty. As a result, it is revealed that the frequency characteristic of core magnetic materials as well as shape dominate major characteristics of the magnetic fields, reactive and dissipative energies in the inductors. Show more

DOI: 10.3233/JAE-2002-477

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 377-382, 2002

Authors: Li, Hui | xTakei, Yoshifuru | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: Our motive of this study is to develop an application of the wavelet packet to PIV image compression processing in order to improve the spatial resolution and reliability furthermore. It was found that the reconstructed PIV image with a lower compression ratio might emphasize particle edges at a relatively high spatial resolution. The reconstructed PIV image with a higher compression ratio may display the large-scale motion of particles and may deduce noisy. In this study, the …relative error of the wavelet packet image compression technique was lower than that of the standard wavelet image compression technique. The higher compression ratio of 64:1 can be realized without losing significant flow information in PIV processing. It could say that the wavelet packet could provide a better compression performance than the standard wavelet image compression technique when compressing PIV images. Show more

DOI: 10.3233/JAE-2002-471

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 383-392, 2002

Authors: Li, Hui | Zhou, Yu | Takei, Masahiro | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: The vector wavelet multi-resolution technique based on the orthogonal wavelet transform was used to analyze the velocity vector data that were simultaneously obtained by sixteen X-wires in the turbulent near-wake of a circular cylinder at different streamwise positions. The instantaneous velocity vector field is decomposed into the multi-scale structures, and its sectional streamline of various scales is displayed. The large-scale structures in the plane of mean shear are consistent with the well-known Kármán vortices. The …structures that correspond to the saddle region between Kármán vortices are identified with the rib-like structures. Even smaller scale structures are also observed. As increasing x/d, the decay of vortical structure and rib-like structure are observed. The topologies of Reynolds stress and RMS vorticity associated with the multi-scale structures are discussed at different downstream positions. It is found that the most significant contribution to Reynolds stress comes from the frequency components of f ≤ 219 Hz at x/d = 20. However, the contribution to Reynolds stress coming from the intermediate-scale structure becomes weak at x/d = 40. The RMS vorticity components of f = 875 Hz is the largest among all components. Show more

DOI: 10.3233/JAE-2002-472

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 393-402, 2002

Authors: Marinova, Iliana | Endo, Hisashi | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: 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. Show more

DOI: 10.3233/JAE-2002-483

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 403-408, 2002

Authors: Endo, Hisashi | Hayano, Seiji | Fujikura, Masahiro | Mogi, Hisashi | Kaido, Chikara | Saito, Yoshifuru

Article Type: Research Article

Abstract: This paper proposes a visualizing methodology of iron loss generation in a magnetic material using its visualized domain images, i.e., SEM, Kerr and Faraday effects. Based on the differential equations for dynamic image, the material behavior is visualized. The state transition matrix of the Helmholtz equation, for which is derived from a series of distinct visualized domain images representing magnetized state. This makes it possible to visualize the magnetizing mechanism as well as iron loss generation. …In the present paper, visualization of iron loss generation on a grain-oriented electrical steel sheet is worked out using a set of SEM images. As a result of our image analysis, magnetization curves at the particular points can be estimated. Show more

DOI: 10.3233/JAE-2002-474

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 409-416, 2002

Authors: Noguchi, So | Yamashita, Hideo | Matsubayashi, Yutaka | Okayama, Eiji

Article Type: Research Article

Abstract: A new interactive visualization system for education and design purposes in 2D electromagnetics is proposed. The proposed system using numerically computational results for several typical model configurations can display interactively electromagnetic field phenomena for any other model configuration bounded with the previously computed ones. It uses simple bilinear interpolation techniques in order to provide fast interactive display. This visualization system can be used for design purposes of problems with different model configurations …and as an educational tool for teaching electromagnetics. Show more

DOI: 10.3233/JAE-2002-482

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 417-422, 2002

Authors: Takei, Masahiro | Li, Hui | Ochi, Mitsuaki | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: A concept to extract a feature of solid-air two-phase flow in a pipeline has been launched with a combination of a capacitance-computed tomography and wavelets transform. With this concept, particle distribution images obtained by CT are transformed with discrete wavelets multiresolution. As a result, in the case of low open area ratios of the pipe cross-section, high particle densities are shown in secondary dominant levels as well as a substantial space level. The high value in …the secondary level resulted from inhomogeneous density due to collision between particles. Show more

DOI: 10.3233/JAE-2002-470

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 423-430, 2002

Authors: Terasawa, Y. | Fujikado, T. | Yagi, T.

Article Type: Research Article

Abstract: In developing a visual prosthesis, it is essential for us to determine its specifications which meet the minimal needs in daily lives of patients. For that purpose, we have proposed a prosthetic vision simulator which enables us to experience prosthetic vision in the virtual space. This time, we applied this system to quantitative evaluation of the reading ability. Experimental results suggested that the electric current intensity in stimulation has small effects to the reading ability.

DOI: 10.3233/JAE-2002-484

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 431-436, 2002

Authors: Yabunami, H. | Hayano, S. | Saito, Y.

Article Type: Research Article

Abstract: As is well known, conventional magnetic circuit theory makes it possible to analyze the three-dimensional magnetic fields, even though its theoretical background is based on the engineering experiences. On the other side, finite elements have a firm theoretical background but it is too expensive to implement the three-dimensional analysis. In order to carry out the three-dimensional magnetic field analysis in a most efficient manner, we propose the theory of modern magnet circuit based on finite elements. …This makes it possible to implement the three-dimensional magnetic field computation in a quite efficient manner. A simple example demonstrates not only the usefulness but also efficiency of our new methodology. Show more

DOI: 10.3233/JAE-2002-476

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 437-442, 2002