Basic Study on Loss Factor Evaluation of Concentrated Winding Permanent Magnet Synchronous Motor

This paper describes the influence of pulse width modulation (PWM) inverter harmonic loss on concentrated winding interior permanent magnet synchronous motor characteristics by using finite element method (FEM) analysis and several measurements. In the measurements, the PWM inverter harmonic loss was evaluated by using a PWM inverter and a sinusoidal power supply. By using the FEM analysis, it was confirmed that the PWM inverter harmonic mainly caused an increase of eddy current losses in the magnetic steel sheet and the permanent magnet. The results indicate that higher inductance of the motor is effective in reducing the harmful effects of PWM inverter harmonics.     

Photodegradation of perfluorooctane sulfonate by UV irradiation in water and alkaline 2-propanol

Perfluorooctane sulfonate (PFOS) is the environmentally concerned compound because of its persistence and bioaccumulative properties. Since photodegradation of PFOS is not yet experimentally confirmed, photodegradation study of PFOS in water and alkaline 2-propanol solution was conducted. Aqueous and alkaline 2-propanol solution of PFOS (40 microM) was irradiated with a low-pressure mercury lamp (254 nm, 32 W) by internal irradiation for 10 d, and then PFOS, fluoride and sulfate ions, and the other degradation products were analyzed. Photodegradation of PFOS was confirmed in both media. PFOS was degraded by 8% after 1 day and by 68% after 10 days irradiation compared to the initial concentration in water. In alkaline 2-propanol, 76 and 92% of PFOS was degraded after 1 and 10 days irradiation, respectively. Photodegradation of PFOS in alkaline 2-propanol was much faster and effective than in water, as the photodegradation rate constants were 0.93 days(-1) in alkaline 2-propanol and 0.13 days(-1) in water, respectively. Formation of fluoride and sulfate was also confirmed by ion chromatography and X-ray diffraction analysis. From observation of the degradation products, two major degradation pathways of PFOS were considered: via C8HF17 and C8F17OH, respectively, resulting in short-chain fluorinated compounds such as C7HF15 and C7F15OH by stepwise removal of CF2. Formation of short-chain fluorocarbons such as CF4, C2F6, and C3F8 were also confirmed. This is the first study to confirm photodegradation of PFOS in water and alkaline 2-propanol.     

Adsorptive removal of fluoride from aqueous solution using orange waste loaded with multi-valent metal ions

Adsorption gels for fluoride ion were prepared from orange waste by saponification followed by metal loading. The pectin compounds contained in orange waste creates ligand exchange sites once it is loaded with multi-valent metal ions such as Al³⁺, La³⁺, Ce³⁺, Ti⁴⁺, Sn⁴⁺, and V⁴⁺ to be used for fluoride removal from aqueous solution. The optimum pH for fluoride removal depends on the type of loaded metal ions. The isotherm experiments showed the Langmuir type monolayer adsorption. Among all kinds of metal loaded gels tested, Al loaded gel appeared to exhibit the most favorable adsorption behavior. The adsorption kinetics of fluoride on loaded gel demonstrated fast adsorption process. The presence of NO₃⁻, Cl⁻ and Na⁺ ions has negligible effect on fluoride removal whereas SO₄²⁻ and HCO₃⁻ retarded the fluoride removal capacity in some extent. Fluoride removal at different adsorbent doses showed that fluoride concentration can be successfully lowered down to the acceptable level of environmental standard. The fluoride adsorption mechanism was interpreted in terms of ligand exchange mechanism. The complete elution of adsorbed fluoride from the gel was successfully achieved using NaOH solution.     

Molecular interaction originating from polar functional group in lubricants and its relationship with their traction property under elastohydrodynamic lubrication

The correlation between molecular interaction and traction properties was investigated using a traction tester and in situ observation of elastohydrodynamic lubrication film with a micro‐Fourier transform infrared spectrometer. The sample oils used were polypropylene glycols (PPGs) with the end‐group of alcohol or ether and a synthetic hydrocarbon oil, poly‐α‐olefin. From the traction tests, it was found that the traction coefficient of PPG was sensitive to the end‐group. PPG with alcohol as the end‐group showed a higher traction coefficient than that with the ether group. In situ observation with a micro‐Fourier transform infrared was performed in order to investigate the molecular interaction of the lubricant oil. It was found that the hydrogen bonding of hydroxyl groups in PPG was strengthened by high pressure in the Hertzian contact region. These results suggest that the rheological properties in the elastohydrodynamic lubrication contact region were affected by the strengthened hydrogen bonding. Copyright © 2014 John Wiley & Sons, Ltd.     

High-performance silicon photonics technology for telecommunications applications

By way of a brief review of Si photonics technology, we show that significant improvements in device performance are necessary for practical telecommunications applications. In order to improve device performance in Si photonics, we have developed a Si-Ge-silica monolithic integration platform, on which compact Si-Ge–based modulators/detectors and silica-based high-performance wavelength filters are monolithically integrated. The platform features low-temperature silica film deposition, which cannot damage Si-Ge–based active devices. Using this platform, we have developed various integrated photonic devices for broadband telecommunications applications.     

A close correlation in the expression patterns of Af-6 and Usp9x in Sertoli and granulosa cells of mouse testis and ovary

Usp9x, an X-linked deubiquitylating enzyme, is stage dependently expressed in the supporting cells (i.e. Sertoli cells and granulosa cells) and germ cells during mouse gametogenesis. Af-6, a cell junction protein, has been identified as a substrate of Usp9x, suggesting a possible association between Usp9x and Af-6 in spermatogenesis and oogenesis. In this study, we examined the expression pattern of Af-6 and Usp9x and their intracellular localization in testes and ovaries of mice treated with or without pregnant mare serum gonadotropin (PMSG), an FSH-like hormone. In both testes and ovaries, Af-6 expression was predominantly observed in supporting cells, as well as in steroidogenic cells, but not in any germ cells. In Sertoli cells, Af-6 was continuously expressed throughout postnatal and adult stages, where both Af-6 and Usp9x were enriched at the sites of Sertoli-Sertoli and Sertoli-spermatid junctions especially at stages XI-VI. In the granulosa cells, Af-6, as well as Usp9x, was highly expressed in primordial and primary follicles, but its expression rapidly decreased after the late-secondary follicle stage. Interestingly, in PMSG-treated mice, the expression levels of Af-6 and Usp9x were synchronously enhanced, slightly in Sertoli cells and strongly in granulosa cells of the late-secondary and Graafian follicles. Such closely correlated expression patterns between Af-6 and Usp9x clearly suggest that Af-6 may be deubiquitylated by Usp9x in both Sertoli and granulosa cells. It further suggests that the post-translational regulation of Af-6 by Usp9x may be one potential pathway to control the cell adhesion dynamics in mammalian gametogenesis.     

Self-ordering of anodic porous alumina formed in organic acid electrolytes

New self-ordering porous alumina films were fabricated in organic acid electrolytes. Highly ordered cell arrangements of porous alumina films were realized in malonic acid at 120 V and tartaric acid at 195 V having 300 nm and 500 nm pore intervals, respectively. Self-organization was achieved at the maximum voltage required to induce high-current-density anodization while preventing burning, i.e., an extremely high-current flow concentrated at local points. The cells of the film grown at a high field must be pressed against each other, so that the self-ordering proceeds with the porous layer growth. When the self-ordering of cell arrangement proceeds, the cells became smaller. To improve the regularity of the cell configuration, a low electrolyte temperature and a relatively high electrolyte concentration were effective for maintaining a high-current-density to prevent burning. Surface flatness was an essential factor for self-ordering, however, the surface oxide film produced by electropolishing an aluminum substrate prevented quick pore growth in the organic acids having a low dissociation constant. It is confirmed that electropolishing followed by alkaline treatment was most appropriate as the pre-treatment in preparing flat surfaces.     

Determination of platelet-activating factor by a chemiluminescence method and its application to stimulated guinea pig neutrophils

A simple, rapid and sensitive chemiluminescence method has been developed to measure platelet-activating factor (PAF). Hydrogen peroxide generated from PAF, upon phospholipase D cleavage, by choline oxidase is determined as chemiluminescence by a luminol-microperoxidase system. The detection limit of PAF by this method is 5 pmol/tube. The method is reproducible with a 5.5% coefficient of variation at 10 pmol of PAF (n=5). Lipids were extracted from guinea pig neutrophils after stimulation with cytochalasin B andN-formyl-methionyl-leucylphenylalanine, and PAF was isolated by high-performance liquid chromatography and determined by chemiluminescence measurements. The amount of PAF detected was 96.1±39.7 (mean ± SD, n=7) pmol/10⁸ cells. This highly sensitive method could be useful for the determination of PAF generated under pathophysiological conditions. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Inactivation of Vegetative Bacteria by Rapid Decompression Treatment

ABSTRACT: We investigated the inactivation and injury effects of hydrostatic pressure treatment combined with a slow decompression (SD treatment) and a rapid decompression (RD treatment) on several vegetative bacterial strains. Single decompression time for the SD and RD treatments was longer than 30 s and about 1 ms, respectively. The RD treatment gave significantly ( P < 0.05) smaller D and z values than the SD treatment, showing that the RD treatment was more effective than the SD treatment in inactivating vegetative bacteria and in lowering the treatment pressure. It was suggested that a rapid decompression procedure could enhance the degree of pressure-mediated injury, which caused the higher bactericidal effect of the RD treatment.     

Plasma Oxidation of a Titanium Electrode in dc-Plasma Above the Water Surface

Plasma oxidation of a titanium electrode above liquid water was investigated to reveal the interaction between metallic titanium and plasma above liquid water. Dc-plasma was generated between the titanium and water electrodes. When the titanium electrode was set as anodal, a thick rutile layer was formed on the surface. We had reported previously that the layer showed the preferred orientation along 〈110〉normal to the surface. The degree of the preferred orientation showed a maximum of 0.8 at the electrode temperature of 1073 K. When the titanium electrode was set as cathodal, a plume was generated with the temperature rise because of the bombarding effect of cationic species in the plasma. The collected particles were spherical and were identified as anatase with a small amount of rutile. Optical emission spectroscopy suggested that an oxide layer (TiO₂) firstly formed on the Ti cathode surface, and then vaporization took place with the temperature rise. The spherical anatase particles were formed from the TiO₂ vapor through the rapid cooling.