Oita Industrial Research Institute

Abstract In recent years, the electrification of automobiles and the studies to electrify also aircraft have accelerated as a measure against global warming, necessitating improvements in motor efficiency and power density to reduce CO 2 emissions. The possibility to increase the motor’s rotation speed is, a key factor in enhancing power density. However, high-speed rotation means that higher operative frequency are used thus increasing eddy currents and iron loss. To mitigate these effects, thin ribbons, powders, and thin magnetically soft wires are effective stator materials. Yet, the magnetic properties of these materials deteriorate when bent to form motor components, making it essential to consider the impact of bending stress on magnetic properties during the motor design stage. This study investigates the effect of bending stress on the magnetic properties of thin wire magnetic materials (electrical steel) using the coaxial H coil method. The magnetic properties and iron loss curves for various bending radii R were determined using this method. The findings of this study will influence the design of motors using thin wire magnetic materials.

A mixture of hydrophilic silicon dioxide (SiO2) and visible-light-reactive tungsten oxide (WOX) has the potential to improve the photocatalytic activity of conventional titanium dioxide (TiO2). This study deposits mixed WOX–SiO2 thin films on TiO2 surfaces by controlling the composition of WOX:SiO2 using radiofrequency sputtering to improve photocatalytic activity and hydrophilicity. The photocatalytic activity is evaluated via the degradation of a methylene blue solution, and hydrophilicity is measured using the water contact angle. In addition, the effect of annealing is determined at 400 °C after deposition. The optical bandgap decreases as the composition of WOX increases and subsequently anneals. The XRD measurements show that polycrystalline monoclinic WO3 peaks appear after annealing when the composition of the mixed WOX–SiO2 thin films only consists of WOX. In contrast, monoclinic WO3 (200) appears after adding SiO2. Atomic force microscopy images show that the grain size decreases as the SiO2 content increases. Moreover, the photocatalytic activity of the mixed WOX–SiO2 thin films improves after annealing. In particular, the mixed WOX–SiO2 thin films that are deposited at a sputter power of WOX:SiO2 = 100:50 W demonstrate a remarkable improvement in photocatalytic activity. Furthermore, the water contact angle of the mixed WOX–SiO2 thin films decreases as the SiO2 content increases and after annealing. This proposed approach can be used for high-performance photocatalytic materials and be widely applied for the fabrication of various semiconducting devices.

In recent years, the precise magnetic properties of electrical steel sheet are needed to develop high efficiency electromagnetic devices. An IEC standard single sheet tester is often used for the magnetic property measurement, especially for commercial transactions. But it is not accurate, so is not proper for the material evaluation based on its precise properties data. Therefore, we developed the measurement technique for the precise magnetic properties of electrical steel sheet. In this paper, two single sheet testers are shown. One is according to IEC standard (IEC-SST), and the other, the Stress load type-Single Sheet Tester (S-SST) is originally designed with our measurement technique for the precise magnetic properties. The key technology for evaluation of electrical steel sheet is proposed, using the S-SST and the IEC-SST. In particular, magnetic field strength distribution in measurement area inside exciting coil and solution of H coil specification difference are studied. And the magnetic properties of the S-SST and the IEC-SST are compared.

In recent years, inverter drive machines such as a hybrid vehicle and an electric vehicle are operated under high voltage pulse with high repetition rate. In this case, inverter surge is generated and affected the machine operation. Especially, the enameled wire of a motor is deteriorated due to the partial discharge (PD) and finally breakdown of the wire will occur. In order to investigate a PD on a resistant enameled wire, characteristics of PD in the twisted pair sample under bipolar repetitive impulse voltages are investigated experimentally. The relationship between the applied voltage and discharge current was measured at PD inception and extinction, and we estimated the repetitive PD inception and extinction voltages experimentally. The corresponding optical emission of the discharge was also observed by using an ICCD camera. Furthermore, ozone concentration due to the discharge was measured during the life-time test of the resistant enameled wires from a working environmental point of view.

Research Article| February 01, 2010 Original structural color preserved in an ancient leaf beetle Gengo Tanaka; Gengo Tanaka * 1Gunma Museum of Natural History, 1674-1, Kamikuroiwa, Tomioka, Gunma 370-2345, Japan *E-mail: tanaka@gmnh.pref.gunma.jp. Search for other works by this author on: GSW Google Scholar Hideki Taniguchi; Hideki Taniguchi 2Oita Industrial Research Institute, 4361-10, Takae-nishi 1, Oita 870-1117, Japan Search for other works by this author on: GSW Google Scholar Haruyoshi Maeda; Haruyoshi Maeda 3Department of Geology and Mineralogy, Kyoto University, Kitashirakawa Oiwakecho Sakyo-ku, Kyoto 606-8502, Japan Search for other works by this author on: GSW Google Scholar Shin-ichi Nomura Shin-ichi Nomura 3Department of Geology and Mineralogy, Kyoto University, Kitashirakawa Oiwakecho Sakyo-ku, Kyoto 606-8502, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information Gengo Tanaka * 1Gunma Museum of Natural History, 1674-1, Kamikuroiwa, Tomioka, Gunma 370-2345, Japan Hideki Taniguchi 2Oita Industrial Research Institute, 4361-10, Takae-nishi 1, Oita 870-1117, Japan Haruyoshi Maeda 3Department of Geology and Mineralogy, Kyoto University, Kitashirakawa Oiwakecho Sakyo-ku, Kyoto 606-8502, Japan Shin-ichi Nomura 3Department of Geology and Mineralogy, Kyoto University, Kitashirakawa Oiwakecho Sakyo-ku, Kyoto 606-8502, Japan *E-mail: tanaka@gmnh.pref.gunma.jp. Publisher: Geological Society of America Received: 14 Jul 2009 Revision Received: 01 Aug 2009 Accepted: 28 Aug 2009 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2010 Geological Society of America Geology (2010) 38 (2): 127–130. https://doi.org/10.1130/G25353.1 Article history Received: 14 Jul 2009 Revision Received: 01 Aug 2009 Accepted: 28 Aug 2009 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Gengo Tanaka, Hideki Taniguchi, Haruyoshi Maeda, Shin-ichi Nomura; Original structural color preserved in an ancient leaf beetle. Geology 2010;; 38 (2): 127–130. doi: https://doi.org/10.1130/G25353.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Greenish-blue metallic colored fossil elytra of the leaf beetle (Plateumaris sp.) have been discovered in the peat sediment of the middle Pleistocene (ca. 600 ka) Hirabaru Formation, Kyushu, Japan. Scanning and transmission electron microscopy revealed the smooth outer surface of the fossil elytra and five alternating electron-dense and electron-lucent layers in the epicuticle. By applying the matrix method to the epicuticle, three reflective peaks of wavelengths 388 nm, 544 nm, and 656 nm were computed. These peaks correspond to the reflective color observed under white light. Thus, the coloration of the fossils was caused by multilayer reflectors of the epicuticle of the elytra. Pyrolysis–gas chromatography–mass spectrometric analysis revealed that the fossil elytra have preserved some of their original macromolecules (chitin, protein, and amino acids), which are similar to those of a related Holocene species. The high-porosity matrix of the peat contains many fragments of diatoms, indicating the high productivity of the water column but a reducing bottom environment. Slight acidity of the interstitial water also seems to contribute to the preservation of some original macromolecules of fossil insects through geologic time. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Residential fuel cells (FCs) have been recently launched in the commercial markets in Japan. The introduction of FCs in residential homes has become a realistic option. We previously proposed energy networks that enabled the interconnection of homes via electricity, heat, and hydrogen networks in order to allow consumers to interchange energy. Further, we have developed a PC-based simulator and an experimental system to evaluate the proposed energy networks. In this paper, analyses on the strategies of the electricity dispatch of FCs and their load sharing in the interconnected homes equipped with the energy networks were performed. The analyses were conducted with the experimental system, PC-based simulator, and a newly constructed mathematical model that optimizes the operation of the FCs with the minimization of both annual energy cost and CO2 emission. The basic characteristics of FC stacks were obtained by experimentations, and these were stored in the PC-based simulator. Four different operational strategies were carried out for four FC stacks, and these strategies were compared. It was concluded from the results that the operational strategies, which have different advantages with regard to efficiency in electricity generation and heat recovery, should be applied depending on the seasonal demand variations