International Journal of Applied Electromagnetics and Mechanics - Volume 52, issue 3-4

Authors: Murai, Masanori | Matsuoka, Shuji | Hirano, Takashi | Yamanaka, Yoshinari | Yamanaka, Kyoji | Takagi, Toshiyuki | Uchimoto, Tetsuya

Article Type: Research Article

Abstract: To eliminate microwave reflections from a truncated-cone antenna element used to irradiate liquid objects with microwaves, the element needs to be designed optimally. Three design parameters were used in the optimization, the objective function to be minimized being power reflection coefficient of the microwaves. An applicable range of relative permittivity for the liquid objects was identified. The characteristics of the antenna were checked in experiments using water. Also the temperature dependency of the antenna was checked in both numerical and experimental tests.

Keywords: Microwave heating, microwave irradiation, microwave antenna, optimum design

DOI: 10.3233/JAE-162136

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1525-1530, 2016

Authors: Sato, Morihiko | Oya, Ryusuke | Ishikawa, Takeo

Article Type: Research Article

Abstract: We have developed a ten stages Marx generator type pulsed power system with MOSFETs. The operation principle of the circuit has been clarified, and the experimental results have confirmed the operation of the developed circuit. In the case of ten stages system, the repetitive operation is verified at the frequency of 1 kHz, and the output voltage of 9.4 kV was obtained. The current was calculated as 36 A, and increasing of the current flowed in the system was achieved. The experiment of the underwater pulsed electrical discharge is performed, and the occurrence of the underwater pulsed electric discharge was …confirmed. Show more

Keywords: Pulsed power, MOSFET, underwater electric discharge

DOI: 10.3233/JAE-162156

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1531-1536, 2016

Authors: Fukuoka, Katsuhiro | Noma, Shota | Kobayashi, Masaki | Ozaki, Tomohiro | Oikawa, Yoshiro

Article Type: Research Article

Abstract: In a rotating-magnetic-field-type magnetizer using a three-pole (three-phase) coil, omnidirectional cracks can be detected via a single test. However, the rotating magnetic field ultimately experiences non-homogeneous distribution in an area far from the centre of the magnetizer. In this study, a multi-coil-type magnetizer that widely obtains uniform rotating magnetic fields was hence developed. Distributions of rotating magnetic flux densities in test object were evaluated using finite-element analysis, and the utility of the multi-coil was confirmed. In addition, the technique for omnidirectional magnetization on whole surfaces of 3D-shaped test object was considered via implementation of the subject multi-coil magnetizer.

Keywords: Magnetic particle testing, rotating magnetic field, multi coil, omnidirectional magnetization, finite element method

DOI: 10.3233/JAE-162174

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1537-1543, 2016

Authors: Fukuoka, Katsuhiro | Horiike, Sho

Article Type: Research Article

Abstract: As magnetic particle testing (MT) detects microcracks using a simplified method, it is used for non-destructive inspection of ferromagnetic materials in various industrial fields. However, MT can provide only a rough distribution shape of a crack; a quantitative technique for evaluating the crack shape has not been established in conventional MT. In the present study, the relationship between the crack shape and the shape of the adhered magnetic particles was revealed by image measurements using a high-speed video camera. We developed a technique for quantitatively evaluating the crack shape from the results of magnetic particle indication in MT.

Keywords: Magnetic particle testing (MT), quantitative evaluation, dynamic image, crack shape estimation, indication

DOI: 10.3233/JAE-162211

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1545-1551, 2016

Authors: Uchida, Yoshihisa | Sugiyama, Hirohiko | Tachino, Shinya

Article Type: Research Article

Abstract: The multi-purpose module system (MMS), a modular robot, comprises joint and function modules. It is possible to transform the MMS into the series-connected and the quadruped forms. This study presents a quadruped form MMS (MMS-G03). In particular, modeling and simulation of MMS-G03 for attitude control is discussed. Two attitude control methods are proposed based on an inverted pendulum model using a state feedback control scheme. The effects of the two methods are evaluated. According to the results, the attitude angle approached the target angle and converged. The attitude angle increased upon increasing the weight rate in both control methods because …of the increase in the moment of inertia of body. The lifted leg method is effective at lower leg length rates, and the supporting leg method is effective at higher leg length rates. The usefulness of the proposed attitude control methods was observed under various module conditions. Show more

Keywords: Multi-purpose module system (MMS), module robot, state feedback control

DOI: 10.3233/JAE-162094

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1553-1560, 2016

Authors: Sim, Sunbo | Le, Minhhuy | Kim, Jungmin | Lee, Jinyi | Kim, Hoon | Do, Hwa-Sik

Article Type: Research Article

Abstract: This paper proposes an encircling-type magnetic camera for inspecting the damage to control rods. The magnetic source and sensors in the magnetic camera were separated from each other, which minimized the electromagnetic interference of adjacent sensors and improved the spatial resolution. An induced current (IC) appears on a control rod whenever a time-varying current is applied to the magnetic source, i.e., an encircling coil. The IC flows along the circumferential direction (θ -direction) of the rod, and generates a time-varying magnetic field in the radial direction (r-direction) around the defect. Bobbin-type integrated Hall sensors are arrayed inside the encircling coil, …and therefore the r-direction magnetic field around the defect is measured. Seventeen Hall sensors were arrayed at a 21° angle with respect to 1.85-mm resolution to measure the electromagnetic field distribution on a stainless-steel small bore piping system, which had an external diameter of 10 mm and a thickness of 0.5 mm. The 40% (1-mm diameter) and 20% (3-mm diameter) depths of the hole-type wears were inspected using the proposed system. In addition, slit-type cracks with a length of 3 mm, depth of 0.2 mm, and width of 0.1 mm in both axial and circumferential directions could be inspected. Show more

Keywords: Control rod, encircling coil, eddy current, sensor array, small bore piping system, magnetic camera, imaging

DOI: 10.3233/JAE-162154

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1561-1567, 2016

Authors: Yazdan, Tanveer | Zhao, Wenliang | Kwon, Byung-Il

Article Type: Research Article

Abstract: This paper proposes a new topology that combines the flux barrier configuration and the split permanent magnet structure of spoke type interior permanent magnet motor (SIPM) with concentrated winding to improve the average torque as well as the quality of torque. The flux barriers can reduce the leakage flux between the magnets inserted in the rotor. Whereas, splitting the magnet across the steel core can decrease the magnetic resistance of the rotor shape. Therefore, both techniques are combined to get their benefits together to improve the output characteristic. The structure is further optimized using Kriging method and Genetic Algorithm to …obtain an efficient design within given constraints of the machine. It is demonstrated that torque constant of optimal model is improved. Moreover, cogging torque and torque ripples are minimized. Finite element analysis is performed to verify the proposed topology and the optimal design. Show more

Keywords: Ferrite magnets, optimization, spoke type motor

DOI: 10.3233/JAE-162195

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1569-1576, 2016

Authors: Ni, Na | Zhang, Ling | Wang, Yin | Shi, Lixin | Zhang, Chi

Article Type: Research Article

Abstract: Structural health monitoring plays a crucial role in maintaining the long lifespan of large-scale infrastructure. In this paper, a new type of sensing technique for localized structural damage is proposed. This technology can be adopted to measure cracks by using a transparent capacitive sensor. The capacitive sensor is fabricated using a dielectric elastomer with attached stretchable transparent electrodes. The electrodes are ionic conductors. The materials of the sensor are transparent and inexpensive, which make the sensory sheets a feasible application for large surfaces without impeding optical signals. The performance transparency of the sensor is beneficial to visually detect the expansion …of cracks through other non-destructive testing technologies. An experiment was conducted to determine the robustness of the capacitive sensor. Tests on perspex sheet and over-reinforced concrete beam demonstrated the ability of the sensor to detect strains and cracks over the surface that it covered. Show more

Keywords: Capacitive sensor, structure health monitoring, ionic skin

DOI: 10.3233/JAE-162215

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1577-1584, 2016

Authors: Suzuki, Junya | Terao, Kyohei | Takao, Hidekuni | Shimokawa, Fusao | Oohira, Fumikazu | Miyagawa, Hayato | Suzuki, Takaaki

Article Type: Research Article

Abstract: We propose a magnetically driven microvalve made of negative photoresist SU-8 containing magnetic pure iron particles as a magnetically driven actuator and valve element. SU-8/Fe composite forms the magnetically driven component using a photolithography and wet etching. The composite valve element made of SU-8/Fe composite in the microchannel is rotated by the external magnetic field of a permanent magnet. The flow reduction ratio of about 44% and the pressure resistance of 4.6 kPa are experimentally measured on the prototype.

Keywords: SU-8/Fe composite, microvalve, magnetic driving

DOI: 10.3233/JAE-162186

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1585-1590, 2016

Authors: Nagase, Masae | Kobayashi, Koichiro | Woo, Taeseong | Takiyama, Yoshihiro | Yamazaki, Keita | Sekino, Masaki

Article Type: Research Article

Abstract: Biomagnetic measurements are affected by environmental magnetic noises emitted by various electric systems including trains and elevators. In this study, we measured low-frequency magnetic noise by using a fluxgate magnetometer at a laboratory located in an urban area and analyzed the dominant noise sources during real-world operation of these systems. Additionally, we evaluated the noise reduction effect of a small, magnetically shielded box combined with compensation coils.

Keywords: Environmental magnetic noises, biomagnetic measurement, extremely-low-frequency magnetic noise, magnetically shielded box

DOI: 10.3233/JAE-162040

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 52, no. 3-4, pp. 1591-1598, 2016