International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Tsukiji, Tetsuhiro | Kodama, Kenta | Nishimura, Shun

Article Type: Research Article

Abstract: A functional fluid flows by itself when electric fields are applied to the functional fluid. This phenomenon is called EHD (electrohydrodynamics) phenomenon, and research and developments are conducted to design motors and pumps using this phenomenon. We use a liquid crystal as a functional fluid and observe the behavior of the liquid crystal as well as flow at the flow channel when steady electric fields are generated through a direct current by two electrodes at the …bottom of the flow channel. Moreover, we investigate the influence of the shape and the position of the electrodes on the liquid crystalline flow under the application of the fields. Furthermore, we research the possibility of designing motors using the EHD phenomenon. Show more

Keywords: Liquid crystal, EHD phenomenon, electric field, direct current, electrode

DOI: 10.3233/JAE-2012-1515

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 589-593, 2012

Authors: Sudo, Seiichi | Goto, Takumi | Shinozaki, Michihiro | Kainuma, Toshiya | Takana, Hidemasa | Nishiyama, Hideya

Article Type: Research Article

Abstract: Experimental study on the dynamic behaviour of magnetic levitating magnet-magnetic fluid element in the external alternating magnetic field is described. Two types of element motions occur according to the magnetic field strength and frequency of the external alternating magnetic field. Seesaw motions of the element and harmonic motions of magnetic fluid surface are observed using high-speed video camera system. Transient phenomena in element response and the change of spikes pattern on the magnetic fluid surface are …revealed. Show more

Keywords: Magnetic fluids, ferrobydrodynamics, interfacial phenomena, alternating magnetic field

DOI: 10.3233/JAE-2012-1516

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 595-601, 2012

Authors: Tanaka, Yoshikazu | Matsumura, Keitaro | Mutsuda, Hidemi

Article Type: Research Article

Abstract: An experimental study of a small, efficient and flexible piezoelectric power generator is presented herein. Forced vibration experiments were performed and the results show linearity between amplitude of output voltage and maximum vibration velocity. Experiments for storage of the power generated were also performed. These confirmed that the power can be stored in capacitors with the time derivative of the stored energy being independent of the capacitance value.

Keywords: Piezoelectric film, flexible piezoelectric device, renewable energy, power storage

DOI: 10.3233/JAE-2012-1517

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 603-608, 2012

Authors: Kikuchi, Hiroaki | Kamada, Yasuhiro | Kobayashi, Satoru | Echigoya, Jyunichi | Watanabe, Hideo

Article Type: Research Article

Abstract: This paper describes the characteristics of magnetic Barkhausen noise (MBN) and permeability on neutron irradiated Fe and Fe-Cu alloys. The plates made of pure Fe and Fe-1 wt.% Cu alloys were prepared with and without cold-rolling. Those plates were irradiated by neutron with a total fluence of 1 × 10^{24} n/m^{2} . Then MBN properties and impedance were measured using magnetic-yokes, a MBN sensor and a pick-up coil. The MBN rms voltage …decreases with neutron irradiation, and the impedance increases after irradiation for cold-rolled specimen. On the other hand, the MBN properties and the impedance at lower frequency have no significant changes after irradiation for undeformed specimen. Contrary, the impedance at higher frequency for undeformed Fe-Cu alloy decreases after irradiation. The relations between those magnetic properties and the microstructure of irradiated materials were also discussed. Those results show the potential of nondestructive evaluation for neutron irradiation embrittlement in reactor pressure vessels. Show more

Keywords: Barkhausen noise (MBN), permeability, impedance, nondestructive evaluation (NDE), neutron irradiation, dislocation, Cu precipitation

DOI: 10.3233/JAE-2012-1518

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 609-614, 2012

Authors: Assimonis, S.D. | Yioultsis, T.V. | Rekanos, I.T. | Kriezis, E.E. | Antonopoulos, C.S.

Article Type: Research Article

Abstract: Electromagnetic bandgaps (EBG) are periodic formations, inspired by photonic crystals, exhibiting prohibited frequency bands for electromagnetic wave propagation. The uniplanar EBG is particularly assessed, due to its fabrication simplicity and is found to exhibit a propagation mode that cancels the desired bandgap behaviour. Two new planar EBG structures, without such modes are presented, retaining the distinct feature of easy fabrication, since the metallic structures are exclusively on the interface layers, with no …vertical connections. The EBGs are optimized to maximize the bandgap, making them suitable for the design of wideband microwave circuits and antennas. Show more

Keywords: Electromagnetic bandgaps, compact antennas, synthetic materials

DOI: 10.3233/JAE-2012-1519

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 615-621, 2012

Authors: Nishida, Hitoshi | Shimada, Kunio | Ido, Yasushi

Article Type: Research Article

Abstract: The effects of the frequency of a pulsed magnetic field on flat polishing were investigated to obtain basic data for increasing the performance and precision of polishing using MCFs. We clarified that the profile curves after polishing differ for a direct-current magnetic field and for a pulsed magnetic field and flattening occurred over a wide range when the frequency of a pulsed magnetic field is 0.1 Hz.

Keywords: Flat surface polishing, magnetic compound fluid, pulsed magnetic field, profile curve, magnetic cluster

DOI: 10.3233/JAE-2012-1520

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 623-628, 2012

Authors: Davino, Daniele | Giustiniani, Alessandro | Visone, Ciro

Article Type: Research Article

Abstract: The analysis of a passive damper employing smart materials is carried out through the description of a concept device loaded by a vibrating mass. Such a device is able to damp vibration and to produce electric energy (energy harvesting). Its basic properties are described in detail and the relationships between damping features and its physical parameters are shown. The analysis is carried out by a linear modeling at first, while the comparison to its actual behaviour …is exploited to justify a more careful study where the material non-linearity is considered. Analytical results on the linear model and the spice numerical analysis of a non-linear model are presented. Show more

Keywords: Energy harvesting, mechanical vibrations, magnetostriction, magnetostrictive devices

DOI: 10.3233/JAE-2012-1521

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 629-635, 2012

Authors: Calvano, F. | Dal Mut, G. | Ferraioli, F. | Formisano, A. | Marignetti, F. | Martone, R. | Rubinacci, G. | Tamburrino, A. | Ventre, S.

Article Type: Research Article

Abstract: A critical aspect of the 3D electromechanical analysis of rotating machinery is the treatment of motion. The paper proposes a technique taking advantage of the numerical characteristics of integral formulations. The motion can be "naturally" modelled because no mesh in the free space and, consequently, in the air gap is required. A frequency domain procedure is presented. It exploits a fixed point iteration technique to deal with magnetic nonlinearities. The procedure is able to determine a …periodic steady state solution of a magneto quasi-static problem with both motional and trasformatoric effects. In order to highlight the effectiveness and the general validity of the approach, some numerical examples are presented, including the calculation of 3D Lorentz force density waveforms in massive non magnetic regions of a large turbine generator. Show more

Keywords: Electromagnetic integral formulation, movement treatment, synchronous generator

DOI: 10.3233/JAE-2012-1522

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 637-643, 2012

Authors: de Oliveira, Elder Eldervitch Carneiro | D'Assunção, Adaildo Gomes | Oliviera, João Bosco L. | Cabral, Alciney Miranda

Article Type: Research Article

Abstract: A new patch antenna using the Minkowski fractal curve and Electromagnetic Bandgap structure on plane ground is proposed. The design was based on HFSS and a prototype was built and measured in order to validate the numerical results. A better impedance matching for the device was obtained using the inset-fed technique. The measured return loss for the proposed antenna at the resonant frequency is lower than −15 dB. The M1 EBG-GP antenna resonant frequency is lower …than that of a corresponding rectangular inset-fed patch antenna. This results in a reduction of 35.6% for this antenna resonating at 2.45 GHz (ISM band). Show more

Keywords: Microstrip antennas, fractal antennas, compact antennas, electromagnetic bandgap, EBG ground plane

DOI: 10.3233/JAE-2012-1523

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 645-649, 2012

Authors: Coco, Salvatore | Laudani, Antonino | Fulginei, Francesco Riganti | Salvini, Alessandro

Article Type: Research Article

Abstract: A new Continuous Flock-of-Starling Optimization (CFSO) procedure is presented for the solution of the inverse problem regarding the accurate design of the Helmholtz coils, usually used for the exposure of biological samples to ELF magnetic field. The CFSO is the continuous equivalent model of the FSO algorithm, and it is expressed in terms of a state space representation. The trajectories of the CFSO particles are obtained as solutions of a differential equations system within suitable Time-Windows …(TWs). Starting from any initial state, thanks to this "continuous" representation, it is increasingly possible to refine the solution by reducing the amplitude of the TWs at any time, during the optimization procedure. Validation results are presented. Show more

Keywords: Inverse problems, Flock-of-Starling Optimization, Helmholtz coils

DOI: 10.3233/JAE-2012-1524

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 651-656, 2012