International Journal of Applied Electromagnetics and Mechanics - Volume 71, issue S1

Authors: Itagaki, Ryo | Kanai, Yasushi | Greaves, Simon

Article Type: Research Article

Abstract: Dual field generation layer (FGL) spin torque oscillators (STO) were investigated for use in microwave-assisted magnetic recording. The STOs were integrated into the gaps of write heads for stable oscillation. According to preliminary calculations, a FGL thickness of 5 nm was suitable, while the volume of 7.5 nm and 10 nm thick FGLs was too large and they did not oscillate stably. The most dominant factor influencing the FGL rotation was found to be the strength of the antiferromagnetic coupling between the FGLs. Other parameters were also varied, e.g., the exchange coupling between the negative spin injection layer (nSIL) and the trailing shield …(TS), however, no significant effect was found. Unlike single FGL STOs, the oscillation frequency changed drastically, from 38 GHz to 73 GHz, on varying the injected current density to the STO. Recording simulations showed that the signal-to-noise ratio was maximized for an STO oscillation frequencies between 34 GHz and 50 GHz, depending on the recording media used in the calculations. Therefore, the dual FGL STO may be suitable for a wide range of recording media. Alternatively, the dual FGL STO may be used for dual-layer recording, where different resonance frequencies are needed for each of the layers, obviating the need for a second STO. Show more

Keywords: Microwave-assisted magnetic recording (MAMR), spin torque oscillator (STO), write heads, micromagnetic simulation

DOI: 10.3233/JAE-220146

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S191-S201, 2023

Authors: Wang, Chenxu | Kawaguchi, Hideki

Article Type: Research Article

Abstract: To investigate portable, low power consumption, low cost and green high-performance computing (HPC) technologies which are suitable for industry applications, authors have been working on the development of dedicated computer based on dataflow architecture for electromagnetic field simulations. In this paper, we propose a Finite Integration Technique (FIT) dataflow machine based on BiCG-Stab scheme for 3-D electrostatic field simulations.

Keywords: HPC technologies, FIT, dataflow machine, BiCG-Stab, electrostatic field simulation

DOI: 10.3233/JAE-220147

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S203-S210, 2023

Authors: Yoshioka, Saijiro | Itaya, Toshiya | Hashimoto, Ryosuke

Article Type: Research Article

Abstract: A water pipe used underwater is required as a method of supplying domestic water to remote islands. In order to ensure this safety, it is necessary to develop maintenance technology for underwater structures. In this research, the deterioration state of the water pipe is clarified, and the remaining life is judged by electromagnetic non-destructive inspection. This method uses the pulse ECT technology.

Keywords: Non-destructive inspection, pulse eddy current testing, water pipes

DOI: 10.3233/JAE-220148

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S211-S220, 2023

Authors: Yoshioka, Saijiro | Gotoh, Yuji

Article Type: Research Article

Abstract: In recent years, the necessity for inspection of the deteriorated oil-refining plant is increased. In the steel tube to be used in a heating furnace has carburizing phenomenon is the cause of the accident. As these carburizing depths increase, so does the steel tube. Therefore, inspection of these depths is important. Therefore, studies are being conducted to determine the life of steel tube by applying electromagnetic non-destructive inspection electromagnetic. However, it is difficult to put it to practical use in the field because measurement error occurs due to the effect of lift-off. In this paper, we proposed an inspection method …that can measure carburizing depth and lift-off at the same time. This method uses two types of search coil. One is the magnetic flux testing and the other is the eddy current testing. Show more

Keywords: Oil-refining plant, carburization depth, cementite, non-destructive inspection, magnetic flux testing, eddy current testing

DOI: 10.3233/JAE-220150

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S221-S228, 2023

Authors: Kato, Masayuki | Hirata, Katsuhiro

Article Type: Research Article

Abstract: In three-phase AC motors, three-phase AC voltage system is essential to generate a rotating magnetic field. Three- phase AC motors also require a three-phase inverter for variable speed and torque operation. In general, the number of switching devices used in three-phase inverter is not less than six and decreasing its number is difficult. This paper focuses on an LC ladder circuit consisting of linear inductors and capacitors. This paper presents a new operating method of the AC motor based on a propagating magnetic field. It is successfully excited by connecting one single-phase AC power supply to the end of the …LC ladder circuit. The induction motor operated by the presented method produces torque as in general induction motors. Show more

Keywords: AC motors, distributed-element circuit, electrical machines, electromagnetic field analysis, LC ladder circuit, rotating magnetic field

DOI: 10.3233/JAE-220152

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S229-S238, 2023

Authors: Givvisis, Panagiotis | Sergiadis, George | Vyzantiadis, Timoleon-Achilleas | Antonopoulos, Christos S. | Symeonidou, Ioanna | Doukas, Anargyros | Kourounis, Drosos | Rabias, Ioannis

Article Type: Research Article

Abstract: A microbicidal Protecting Breathing Device using an Ultraviolet Germicidal Irradiation (UVGI) air-sterilization unit, is designed and analyzed. The system is producing short-wave UV light which inactivates bacteria, viruses, and protozoa and it is connected to a full-face mask supplying sterilized inhaled air to the user and in a unique way, also sterilizes the exhaled air back to the ambient environment so covering the case of an asymptomatic transmitter. A dedicated control system is developed and built in the device for a full surveillance of the system.

Keywords: Breathing device, UVC

DOI: 10.3233/JAE-220153

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S239-S244, 2023

Authors: Hayashi, Shogo | Igarashi, Hajime

Article Type: Research Article

Abstract: A hybrid optimization method that combines parameter optimization (PO) with topology optimization (TO) is proposed for the design of a permanent magnet (PM) motor. The PM shape, configuration, and flux barrier topology were simultaneously optimized using the proposed method. The conventional hybrid method that deals with a single PM is effectively extended to deal with multiple PMs parameterized by several geometrical parameters. The use of this extension makes it possible to search for the optimal rotor structure of the multiple-PM motor, which is widely used in electric vehicles. The results obtained by the proposed method are shown superior over those …obtained by conventional method. The rotor structure with double-U shaped PMs with small flux barriers near the airgap was obtained by the optimization. Show more

Keywords: Automatic mesh generation, parameter optimization (PO), permanent magnet (PM) motors, topology optimization (TO)

DOI: 10.3233/JAE-220154

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S245-S255, 2023

Authors: Gong, Zhi | Yang, Shiyou

Article Type: Research Article

Abstract: The Euler–Lagrange method is proposed for the rigorous modeling of low-frequency metamaterial (MTM) slabs in near field systems. The mechanisms of the extraordinary performance-enhancing capabilities of MTM slabs in near field systems are analyzed in numerical studies. The proposed method is verified by experimental studies of a prototype MTM-coil system. This work focuses on low-frequency MTM slabs and enables rigorous, flexible, and feasible analysis of MTM-based near field systems in electrical engineering.

Keywords: Metamaterial, magnetic field, numerical modelling

DOI: 10.3233/JAE-220155

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S257-S263, 2023

Authors: Shi, Ce | Sun, Feng | Xu, Fangchao | Jin, Junjie | Tong, Ling | Zhou, Qing | Oka, Koichi

Article Type: Research Article

Abstract: Traditional scroll compressors are difficult to achieve oil-free operation due to the presence of a high-friction anti-rotation mechanism. This paper proposes a magnetic drive oil-free scroll compressor to solve this problem. Firstly, the structure and principle of this scroll compressor are introduced. Then the finite element analysis of the electromagnetic system was conducted; the dynamics model of the magnetic scroll compressor operating in the uncompressed state was established. Finally, the PID control of the system is performed, and simulations and experiments are carried out. Experimental results: under the 0.05 mm step signal in the X direction, the position response time …of the system is 0.1 s, and the angle response time of 0.001 rad is 0.2 s. The results show that the oil-free scroll compressor has good position control response characteristics. Show more

Keywords: Oil-free scroll compressor, magnetic drive, PID control, experimental study

DOI: 10.3233/JAE-220157

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S265-S274, 2023

Authors: Liu, Qiao | Otomo, Yoshitsugu | Gong, Yunyi | Igarashi, Hajime

Article Type: Research Article

Abstract: The resistance and inductance of an inductor working at high frequencies depend on frequency because of eddy currents caused by the skin and proximity effects. In addition, the stray capacitance among winding coils would give significant influence. This paper proposes an equivalent circuit model which can consider the displacement and eddy currents simultaneously in frequency and time domain. In the proposed circuit model, the capacitance and complex inductance are determined by solving electrostatic and magnetostatic equations with finite element method (FEM). It is shown that the input impedance of an air-core coil is consistent with that computed by FEM at …low frequencies. Moreover, the former is shown to be consistent with the measured result. Show more

Keywords: Inductor, equivalent circuit, eddy current, displacement current, self-resonant

DOI: 10.3233/JAE-220160

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 71, no. S1, pp. S275-S282, 2023