International Journal of Applied Electromagnetics and Mechanics - Volume 28, issue 1-2

Authors: Ueno, Toshiyuki | Higuchi, Toshiro

Article Type: Research Article

Abstract: This paper presents a miniature positioning device using Iron-Gallium alloy (Galfenol). Galfenol is a ductile magnetostrictive material with magnetostriction more than 200 ppm, Young's modulus of 70 GPa and high permeability. The actuator consists of a small pin of Galfenol, 1 mm diameter fabricated by ultra high precision cutting, winding coil, housing, and brass mover clamped on a frictional rod. The movement is based on the smooth impact drive mechanism, where the mover frictionally supported is …moved step by step by inertia force with the rapid expansion and slow contract of the Galfenol pin. The miniature device driven less than 3 V was verified the velocity of 1 mm/s at driving frequency of 2 kHz with no-traveling limit, which will be applicable for positioning mechanism for mobile electronics. Show more

Keywords: Iron-gallium alloy, micro actuator, ultra high precision cutting, smooth impact drive mechanism

DOI: 10.3233/JAE-2008-968

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 135-141, 2008

Authors: Motozawa, Masaaki | Sawada, Tatsuo

Article Type: Research Article

Abstract: Velocity and attenuation of ultrasonic propagation in magnetic fluids subjected to a magnetic field are examined experimentally. Measurements are taken while changing the magnetic field intensity and the angle between the magnetic field direction and the ultrasonic propagation direction. The ultrasonic propagation velocity and attenuation are dependent on the intensity and the elapsed time of the magnetic field. When the magnetic field is applied to magnetic fluid, magnetic particles form clustering structures and they …effect on ultrasonic propagation in a magnetic fluid. Based on experimental results, the influence of the inner structure of the magnetic fluids on the properties of ultrasonic propagation is discussed. Show more

Keywords: Magnetic fluid, ultrasound, ultrasonic propagation velocity, attenuation, hysteresis

DOI: 10.3233/JAE-2008-969

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 143-148, 2008

Authors: Joshi, Ameet

Article Type: Research Article

Abstract: Magnetic flux leakage (MFL) technique is commonly used for inspection of gas transmission pipelines. MFL signal is used to identify and characterize defects in the pipeline by estimating their length, width and depth (LWD). Knowledge of LWD alone is highly inaccurate and coarse compared to actual 3D geometry of the defect for predicting the maximum allowable operating pressure (MAOP) of the pipe. However, the inverse problem associated with prediction of 3D geometry is not only ill …conditioned, but also involves complex numerical computation. As a result, little research has been done in this area. Author has published two different methods of dealing with this problem in collaboration with fellow researchers. This paper reviews the two approaches for estimating 3D depth profile of a defect from the corresponding MFL signal based on radial basis function neural network (RBFNN) and discrete wavelet transform (DWT). Show more

Keywords: 3D defect characterization, adaptive wavelet transform, radial basis function neural network, magnetic flux leakage inspection

DOI: 10.3233/JAE-2008-970

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 149-153, 2008

Authors: Wang, Li | Chen, Zhenmao | Lu, Tian-Jian | Xu, Minglong | Yusa, Noritaka | Miya, Kenzo

Article Type: Research Article

Abstract: In this paper, a scheme for reconstruction of a long Stress Corrosion Crack (SCC) from 2D ECT signals is proposed based on a multiple crack segments strategy. The profiles of inner and edge crack segments are reconstructed separately by using signals at different scanning direction. A hybrid scheme of the Conjugate Gradient (CG) method and the advance-retreat method are introduced to reconstruct the crack conductivity and crack size. Several cracks of complicated profile are reconstructed from …simulated ECT signals of a conductive SCC model. The numerical results verified the validity of the proposed scheme. Show more

Keywords: Multisegment ECT inversion, long stress corrosion crack, 2D signal simulation, hybrid inversion method

DOI: 10.3233/JAE-2008-971

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 155-161, 2008

Authors: Suzuki, Takayuki | Sasamoto, Akira | Nishimura, Yoshihiro | Teramoto, Tokuo

Article Type: Research Article

Abstract: The forward and inverse analyses of MFM images were performed to develop materials characterization technique using magnetic force microscopy. By the forward analysis of artificial magnetic recording media, the MFM images become focused with decreasing lift off height until 30 nm, both in a point dipole magnetic tip and in a finite size (50 nm) magnetic tip. However, in the case of the finite size magnetic tip, MFM images become degraded and especially duplicated at magnetic …phase boundaries below 30 nm lift off height. By the inverse analysis of artificial magnetic recording media, the original magnetic charge was fully reconstructed using deconvolution and inverse Fourier transform techniques. By applying this technique to the experimental MFM image for ferromagnetic shape memory alloy, clear and noiseless martensite of variant structure was obtained from the MFM image. Show more

Keywords: Magnetic force microscopy, forward analysis, inverse analysis, deconvolution, inverse Fourier transform, magnetic charge, ferromagnetic shape memory alloy, martensite

DOI: 10.3233/JAE-2008-972

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 163-169, 2008

Authors: Nishimura, Yoshihiro | Sasamoto, Akira | Suzuki, Takayuki

Article Type: Research Article

Abstract: UT scanner must have the sampling intervals and a beam spot size smaller than potential flaws in materials in order to be able to detect them. If material longer than 1m must be tested with a pitch of 1mm, more than 1000 scan lines are needed to detect flaws, and the material cannnot be examined in common production lines. The number of horizontal scanning lines must be decreased to reduce testing time. Alternatively, the scanning speed must be …increased. This study performs propagation analysis of an acoustic wave emitted from a probe and presents methods and the formulas to reconstruct 3D image of flaws in the sample with fewer horizontal scanning lines. Show more

Keywords: EMAT, image reconstruction, FFT, convolution

DOI: 10.3233/JAE-2008-973

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 171-176, 2008

Authors: Maruyama, Takayuki | Igarashi, Hajime

Article Type: Research Article

Abstract: Robust optimization searches for optimal solutions which remain feasible under the effect of uncertainties. The conventional robust optimization, however, often requires great computational cost to find robust solutions. This paper introduces a novel robust optimization method based on genetic algorithm. In this method, individuals with "good" performance are selected and tested for their robustness for reduction of computational time. It is shown that the present method works in shorter time in comparison with …the conventional robust optimization. Show more

Keywords: Robust optimization, genetic algorithm, SMES

DOI: 10.3233/JAE-2008-974

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 177-185, 2008

Authors: Campelo, Felipe | Watanabe, Kota | Igarashi, Hajime

Article Type: Research Article

Abstract: Topology optimization (TO) is a promising field for the design of industrial devices, since it can allow computational tools to develop creative solutions independently of initial topologies. However, the generation of smooth solutions, i.e., solutions that can be physically implemented, remains a challenge for most TO techniques available. In this paper, we discuss a set of operators that allow smoother topologies to be generated by an evolutionary topology optimization algorithm based on the artificial immune systems …paradigm. The design of an electromagnetic device is used as a test case for the proposed methodology. Show more

Keywords: Topology optimization, smoothness, artificial immune systems

DOI: 10.3233/JAE-2008-975

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 187-192, 2008

Authors: Kaniusas, Eugenijus | Pfützner, Helmut | Mehnen, Lars | Kosel, Jürgen | Hasenzagl, Andreas

Article Type: Research Article

Abstract: Magnetostrictive bilayer sensors have been successfully applied on the skin for the registration of various physiological quantities, ranging from the cardiorespiratory activity to the blood pressure changes. The application region was varied from the neck down to the calf. Thus an optimization of the sensor parameters becomes an increasingly important issue. Here the optimisation is considered with respect to curvature, bending momentum, and temperature of the bilayer. The results yield different requirements for …different skin regions. In order to control the cross-sensitivity of the sensor, special sensor set-ups are introduced to reduce bending or thermal sensitivity, which is relevant for various medical areas. Show more

Keywords: Magnetostrictive bilayers, skin curvature sensors, thermal sensors, bending momentum sensors, physiological sensors

DOI: 10.3233/JAE-2008-976

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 193-199, 2008

Authors: Grimberg, Raimond | Udpa, Lalita | Udpa, Satish S.

Article Type: Research Article

Abstract: Determination of soil condition is important for several applications ranging from agricultural to homeland security. This paper presents a novel electromagnetic sensor array, the method for solving its forward problem and the super-resolution algorithm for signal processing to detect conductive objects buried in the ground, by determination of soil condition.

DOI: 10.3233/JAE-2008-977

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 28, no. 1-2, pp. 201-210, 2008