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Mantani Y.,National College of Technology, Suzuka College | Kudou K.,Kanagawa University
Journal of Alloys and Compounds | Year: 2013

The purpose of this study was to investigate and discuss the effect of plastic deformation on material properties, such as Young's modulus and internal friction, of the martensite structures in Ti-Nb alloys. A characteristic of the structure of Ti-10Nb alloys is the twin α structure. For Ti-15Nb alloys, it is the α′ martensite structure and for Ti-20Nb alloys, it is the α″ martensite structure. In the twin α structure, Young's modulus decreased slightly and the internal friction increased gradually with an increase in the rolling reduction rate. In the α′ martensite structure, Young's modulus decreased slightly and the internal friction decreased gradually with an increase in the rolling reduction rate. On the other hand, in the α″ martensite structure, Young's modulus decreased and the internal friction increased drastically at a weak plastic deformation. After that, Young's modulus was almost stable and the internal friction decreased with further deformation. The change in the material properties of the α′ martensite structure was considered to be caused by a decrease in the lattice constants, like a reverse transformation from α′ to α or the emission of a dislocation. The change in the material properties of the α″ martensite structure was considered to be caused by the change in the internal microstructure, such as the increase in the dislocation or twin. © 2012 Elsevier B.V. All rights reserved. Source


Islam M.Z.,University of Shizuoka | Alam J.M.,University of Shizuoka | Tamba Y.,National College of Technology, Suzuka College | Karal M.A.S.,University of Shizuoka | Yamazaki M.,University of Shizuoka
Physical Chemistry Chemical Physics | Year: 2014

We recently developed the single giant unilamellar vesicle (GUV) method for investigating the functions and dynamics of biomembranes. The single GUV method can provide detailed information on the elementary processes of physiological phenomena in biomembranes, such as their rate constants. Here we describe the process of pore formation induced by the antimicrobial peptide (AMP), magainin 2, and the pore-forming toxin (PFT), lysenin, as revealed by the single GUV method. We obtained the rate constants of several elementary steps, such as peptide/protein-induced pore formation in lipid membranes and the membrane permeation of fluorescent probes through the pores. Information on the entry of the cell-penetrating peptide (CPP), transportan 10 (TP10), into a single GUV and its induced pore formation in lipid membranes was also obtained. We compare the single GUV method with other methods for investigating the interaction of peptides/proteins with lipid membranes (i.e., the large unilamellar vesicle (LUV) suspension method, the GUV suspension method, and single channel recording), and discuss the pros and cons of the single GUV method. On the basis of these data, we discuss the advantages of the single GUV method. This journal is © the Partner Organisations 2014. Source


Iwata M.,National College of Technology, Suzuka College | Jami M.S.,International Islamic University Malaysia
Drying Technology | Year: 2010

This article presents an efficient approach for the analysis of combined electroosmotic dewatering (EOD) and mechanical expression (ME) using the Terzaghi-Voigt combined model by considering creep deformation of the material. The EOD-ME process enhances dewatering because it combines the advantage of electroosmosis and mechanical dewatering, resulting in reduced void ratio compared to individual operation. The basic differential equation based on the model is solved analytically by assuming that both an electroosmotic pressure gradient Epg and a modified consolidation coefficient Ce of the material are constant, resulting in the equation of solid compressive pressure in the material as a function of time and position. The analysis also leads to the equation of the average consolidation ratio Uc, which is a measure of the progress of dewatering; this equation can describe well the empirical results under various conditions. The proposed approach can clearly explain the relationship of the driving forces of individual mode of operation. The large water content of semisolid bentonite-water mixture can effectively be reduced by the EOD-ME combined operation analyzed in this research. © 2010 Taylor & Francis Group, LLC. Source


Oono Y.,Daido University | Sounai A.,National College of Technology, Suzuka College | Hori M.,Daido University
Journal of Power Sources | Year: 2012

The mechanism underlying the decline in cell voltage over time was investigated for high-temperature proton exchange membrane fuel cells. Five identical cells were prepared and long-term power generation tests were conducted at an operation temperature of 150 °C and a current density of 0.2 A cm -2 for periods of up to 17,860 h. Each of the cells was then analyzed using transmission electron microscopy and electron probe micro-analysis (EPMA). The results indicated that growth of the Pt catalyst particles occurred during operation, in addition to oxidation of the carbon support. Degradation of the catalyst layers was investigated by EPMA of cross sections of the membrane electrode assemblies, allowing the mechanism of cell performance reduction to be clarified. © 2012 Elsevier B.V. All rights reserved. Source


Yukawa H.,Nagoya University | Nambu T.,National College of Technology, Suzuka College | Matsumoto Y.,Oita National College of Technology
Journal of Alloys and Compounds | Year: 2011

The alloying effects of tungsten on the hydrogen solubility and the hydrogen permeability are investigated for V-based hydrogen permeable membranes. The hydrogen solubility is found to decrease by the addition of tungsten into vanadium or by increasing the temperature. It is shown that the ductile fracture occurs for V-5 mol%W alloy even in the hydrogen pressures of 0.3 MPa at 773 K. It is also found that the mechanical properties (i.e., strength and ductility) of V-based alloy are better than that of Nb-based alloy in hydrogen atmosphere at high temperature. It is demonstrated that the V-5 mol%W alloy possess excellent hydrogen permeability without showing any hydrogen embrittlement when used under appropriate permeation conditions, i.e., temperature and hydrogen pressures. © 2010 Elsevier B.V. All rights reserved. Source

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