International Journal of Applied Electromagnetics and Mechanics - Volume 19, issue 1-4

Authors: Cieśla, Antoni

Article Type: Research Article

Abstract: Superconductor separators are a new generation of magnetic separators; a DC superconductor electromagnet may be used as a source of magnetic field. It creates, among other things, a chance to reject weak-magnetic particles – first of all extra small ones (the basic problem for beneficiation of useful minerals). The subject of the following considerations refers to one from several possible constructions: a matrix high-gradient separator equipped with the DC superconductor electromagnet. Some practical …aspects of the construction of the device in laboratory scale as well as the problems of exploitation conditions of the separator are presented. Show more

Keywords: superconductor magnet, magnetic separation, matrix high gradient separator

DOI: 10.3233/JAE-2004-585

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 327-331, 2004

Authors: Franchois, Ann | Lewyllie, Peter | Taerwe, Luc

Article Type: Research Article

Abstract: A microwave non-destructive testing technique to localize metal reinforcement bars in a concrete wall is presented. The technique is based on a two-dimensional near-field Synthetic Aperture Radar imaging algorithm in a monostatic stepped frequency arrangement. The resulting, qualitative, images of the induced sources give a clear indication on the position of the highly conductive rebars, thanks to their strongly reflective properties. The algorithm takes into account the presence of the concrete, the complex …permittivity of which is assumed to be known. The technique has been succesfully tested on simulated and experimental data for a number of concrete wall samples with various reinforcement configurations. Show more

Keywords: non-destructive testing, reinforced concrete, Synthetic Aperture Radar (SAR), microwave imaging

DOI: 10.3233/JAE-2004-586

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 333-338, 2004

Authors: Meydan, Turgut | Marketos, Philip

Article Type: Research Article

Abstract: The construction of stacked transformer cores, typically built by single layers of lamination overlapping each other, is a time consuming procedure adding to their manufacturing cost. This paper presents novel core designs made out of consolidated stacks of electrical steel, which enable the cores to be built much faster, in some cases causing a reduction in power loss compared to conventional core designs.

DOI: 10.3233/JAE-2004-587

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 339-343, 2004

Authors: Rubinacci, Guglielmo | Tamburrino, Antonello | Ventre, Salvatore | Villone, Fabio

Article Type: Research Article

Abstract: We propose an efficient numerical procedure to iteratively compute the perturbation of the magnetic field (in the magnetoquasistationary limit) due to a volumetric defect of arbitrary shape embedded in a conducting domain. The procedure, which is particularly suitable in view of the solution of the inverse problem, is based on an integral formulation of the eddy current problem in terms of the electric vector potential expanded using edge elements.

Keywords: eddy currents testing, volumetric defects

DOI: 10.3233/JAE-2004-588

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 345-349, 2004

Authors: Shimada, Kunio | Shuchi, Shigemitsu | Fujita, Toyohisa | Miyazaki, Toshio | Shibayama, Atsushi | Kamiyama, Shinichi

Article Type: Research Article

Abstract: We experimentally investigated the relation of shear stress to shear rate of improved magnetic compound fluid (MCF) in engineering applications such as dampers and micro-polishing. The newly improved MCF is composed of smectite particles in a MCF previously developed by Shimada. In the new MCF, the particle distribution is more stable and the particles do not sediment. In the context micro-polishing, the relation of shear stress to shear rate in the newly improved MCF containing abrasive …particles was investigated. The addition of the abrasive or smectite particles makes the shear stress change little in regard to changes in shear rate. Thus, the newly improved MCF can be applied to the micro-polishing of material surfaces at existing shear rates. Show more

DOI: 10.3233/JAE-2004-589

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 351-354, 2004

Authors: Jabbar, M.A. | Azeman, Azmi Bin

Article Type: Research Article

Abstract: A Reduced-Basis Finite Element Method has been used for fast and accurate alternative to standard Finite Element algorithms for optimisation problems. Improvement in computational speed is derived from the use of a single static mesh for 'basis' calculations and through application of geometric transformations for regions where variations are required. The method is applied on an 8-pole/9-slot spindle motor used in Hard Disk Drives for the minimization of cogging torque. The desired outcome is a robust …algorithm possessing the accuracy of Finite Element Analysis and improved speed of computation. Show more

Keywords: finite elements, reduced basis, optimisation, cogging torque

DOI: 10.3233/JAE-2004-590

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 355-360, 2004

Authors: Kojima, Hiroyuki | Morito, Akihiro | Konno, Katsuhiro | Kobayashi, Toshio

Article Type: Research Article

Abstract: This study deals with the residual vibration reduction control after catching a falling steel sphere by a two-link catching flexible robot arm. The two-link catching flexible robot arm consists of a first rigid link, a second flexible link and a cup mounted to catch the falling steel sphere. The flexibility of the second flexible link is effectively utilized to reduce the shock owing to the contact between the falling steel sphere and the cup. Then, the …equation of motion of the two-link catching flexible robot arm is obtained, and the cost function for the residual vibration reduction control after catching the falling steel sphere is defined as a function of the parameters of the second joint angular velocity profile. By making the contour map of the cost function, the optimal parameters of the second joint angular velocity profile is obtained. The residual vibration reduction control is implemented by the feedforward control based on the second joint angle trajectory with the optimal parameters. Furthermore, the numerical calculations and the experiments have been carried out, and it is confirmed that the residual vibrations of the second flexible link after catching the falling steel sphere can be extremely reduced. Show more

Keywords: residual vibration reduction, catching, falling steel sphere, flexible robot arm, cost function, contour map, trajectory

DOI: 10.3233/JAE-2004-591

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 361-366, 2004

Authors: Azoum, Karim | Besbes, Mondher | Bouillault, Frédéric

Article Type: Research Article

Abstract: The aim of this work is to present a three-dimensional generalized finite element modelling of magnetostrictive materials including direct and inverse effects through strongly coupled magnetic and elastic behaviours. Emphasis is put on adapted constitutive laws that incorporate explicitly the physical coupling between magnetic and mechanical magnitudes. We used a variational formulation in terms of magnetic vector potential circulation and displacement. The studied example is composed of a solenoid with a magnetostrictive …core where a three dimensional analysis is performed. Show more

Keywords: magnetostriction, coupled constitutive laws, 3D FEM analysis

DOI: 10.3233/JAE-2004-592

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 367-371, 2004

Authors: Yashkir, Yuri | Nantel, Marc | Hockley, Bernard

Article Type: Research Article

Abstract: This paper is focused on the systematic computer-based numerical research of processes taking place during laser/matter interaction on the nanosecond time scale. Special attention is paid to the dynamics of a laser with passive Q-switch and intra-cavity nonlinear frequency doubling. The model accounts for the whole set of processes: laser beam attenuation and absorption in the material, heat generation, heat diffusion, phase transitions (solid to liquid, liquid to gaseous state), material removal and melted material …re-solidification. Through analysis and simulation of the laser model, we investigate the laser pulse formation and laser parameter optimization. Numerical experiments are used to explain crater shapes, rate of material removal, dependence on laser pulse duration, etc. Show more

Keywords: laser pulse, numerical modeling, second harmonic, micro machining, heat diffusion

DOI: 10.3233/JAE-2004-593

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 373-377, 2004

Authors: Akita, Masanori | Abe, Takanori | Midorikawa, Yoichi

Article Type: Research Article

Abstract: This paper describes the spectral modification method for signals polluted with noise. In this case, the spectral subtraction method is usually used. Instead of the spectral subtraction method, the spectral features of noisy signals are modified using some rules. However, irregular modifications occur in case the environment is polluted with colored noise. In this paper, improved modification rules for adding valleys to the spectral envelopes of signals under the noise environment is presented. Two types of …threshold functions are presented and the stability of the intersection point between threshold functions and original spectral envelopes improved. The improvement of the spectral shape after this modification is shown and experimental results of pattern recognition are also shown. Show more

Keywords: signal enhancement, colored noise, spectral subtraction

DOI: 10.3233/JAE-2004-594

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 379-383, 2004