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The History of Bioelectromagnetism
Published in Shoogo Ueno, Tsukasa Shigemitsu, Bioelectromagnetism, 2022
Tsukasa Shigemitsu, Shoogo Ueno, Masamichi Kato
In the past, the magnetic field strength of a permanent magnet was too weak to demonstrate the magnetic-related phenomena of diamagnetism and paramagnetism. Around the 1980s, the magnetic field strength of a permanent magnet increased drastically due to the development of neodymium magnets. This opened a new era for the study of the magnetic properties of every material in high magnetic fields. In the presence of a neodymium magnet, the magnetic properties of diamagnetic materials can be observed with the naked eye. With neodymium magnets, apples, eggs, carbon, bismuth, etc. can be levitated. A neodymium magnet is a rare earth magnet (Nd2Fe14B) consisting mainly of neodymium, iron, and boron. It was invented by Masato Sagawa and others at Sumitomo Special Metals (later, Hitachi Metals), Japan. It is a powerful permanent magnet (Sagawa et al., 1984). At the same time, a new powerful permanent magnet was invented and reported by General Motor Corporation, USA (Croat et al., 1984). The typical research developments will be introduced as magnetic-related phenomena; levitation of diamagnetic materials and physical property changes of water and Moses effects.
Hybrid Power for Mobile Systems
Published in Yatish T. Shah, Hybrid Power, 2021
Brushless DC motors (BLDC) are widely used in the hybrid car market. BLDC motors are theoretically the result of reversing the position of the stator and rotor of PM DC motors. Specifically, they are of a type called an interior permanent magnet (IPM) machine (or motor). These machines are wound similarly to the induction motors found in a typical home, but (for high efficiency) use very strong rare-earth magnets in the rotor. These magnets contain neodymium, iron, and boron, and are therefore called Neodymium magnets. Cutting edge U.K. motors that are now being produced are using Neodymium Permanent Magnet technology. As security of supply returns, it is certain that there will accordingly be a return to superior motor designs that NdFeB Permanent Magnets enable [2,8]. Their main advantages are high efficiency, compactness, and high energy density. The literature [6] has shown that a 5-phase brushless fault-tolerant hybrid-excitation motor can be used for EV applications. BLDC can also be used for EV by means of a fuzzy-tuned PI speed control. A brushless dual-rotor flux switching permanent magnet motor can be used for PHEV application. A double-stator permanent magnet BLDC (PMBLDC) can also be engaged for HEV application. These and other modifications, research, and development reported in the literature are described in great detail by Singh et al. [6].
Permanent Magnet Motors and Halbach Arrays
Published in Ranjan Vepa, Electric Aircraft Dynamics, 2020
Neodymium magnets, which are the most common type of rare-earth magnets, are made from an alloy of neodymium, iron and boron (Nd2Fe14B). Samarium–cobalt (SmCo5) magnets are typically two to three times stronger than ferrite or ceramic-type permanent magnets and could be used for the construction of electric motors. The sintered neodymium-iron-boron (NdFeB) hard magnetic material was patented by Sumitomo Special Metals in 1983 and it brought about a big change in the performance of electric motors.
Development of an articulated mobile robot moving on magnetic curved walls and passing over obstacles
Published in Advanced Robotics, 2022
Shotaro Ueno, Mizuki Nakajima, Motoyasu Tanaka
In previous researches, several wall climbing methods have been considered such as adhesive [24], negative pressure [25, 26] and magnetic [27]. In the adhesive method, the adhesive strength will be reduced over time due to dust or deterioration of the material. The method that uses negative pressure is not suitable for curved surfaces or obstacle traversing because the suction unit must be in contact with the wall without any clearance. Since the target inspection tank is magnetic, a method using magnetic force is adopted. Permanent magnets are used as the adsorption mechanism to reduce the weight and simplify the system. Neodymium magnets are used because of their light weight and strong attraction force.