Ashikaga Institute of Technology
Tochigi, Japan

Ashikaga Institute of Technology is a private university in Ashikaga, Tochigi, Japan, established in 1967. Wikipedia.

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Kobayashi S.,Ashikaga Institute of Technology | Maruyama T.,Ashikaga Institute of Technology | Tsurekawa S.,Kumamoto University | Watanabe T.,Northeastern University China | Watanabe T.,Tohoku University
Acta Materialia | Year: 2012

The effect of grain boundary microstructure on the fracture resistance of sulfur-doped polycrystalline nickel was investigated using specimens with different grain boundary microstructures to reveal the usefulness of grain boundary engineering for control of segregation-induced intergranular brittle fracture of polycrystalline materials. The sulfur-doped polycrystalline nickel specimen with more homogeneous fine-grained structure and a higher fraction of low-Σ coincidence site lattice (CSL) boundaries shows higher fracture resistance than the specimen with coarse-grained structure and a lower fraction of low-Σ CSL boundaries. It was found that high-energy random boundaries play a key role as the preferential crack path in fracture processes. The resistance to sulfur segregation-induced intergranular brittle fracture was evaluated by analyzing the fractal dimension of random boundary connectivity in the polycrystalline nickel specimens studied. The fractal dimension of random boundary connectivity decreases with increasing fraction of low-Σ CSL boundaries, resulting in the generation of a higher fracture resistance by restricting more frequent branching and deflection of propagating crack path along random boundaries from the main crack. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Kobayashi S.,Ashikaga Institute of Technology | Tsurekawa S.,Kumamoto University | Watanabe T.,Northeastern University China | Palumbo G.,Integran Technologies Inc
Scripta Materialia | Year: 2010

Control of brittleness associated with segregation of sulfur to grain boundaries in ultrafine-grained nickel was investigated. The brittleness could be successfully improved by controlling the grain boundary microstructure. The specimens with a higher fraction of special boundaries can have higher fracture toughness even in sulfur-bearing condition. It is evident that grain boundary engineering is applicable to controlling segregation-induced embrittlement in ultrafine-grained materials. © 2009 Acta Materialia Inc.

Tobita R.,Ashikaga Institute of Technology
Communications in Computer and Information Science | Year: 2016

This study examined the effectiveness of analysis with near-infrared spectroscopy (NIRS) for English as foreign language (EFL) training, from a brain science perspective. The experiment presented in this paper analyzed the amount of blood flow in the brain while learners were training to improve their English listening skills. The experiment attempted to ascertain the preferable combinations of learners’ characteristics and teaching materials when learners are completing training in English listening. This was done by comparing the brain activities of learners from different English proficiency levels. The data suggests that the analysis, using Functional Near-Infrared Spectroscopy (fNIRS), enabled the proposition of an effective course design for EFL learners. © Springer International Publishing Switzerland 2016.

Kobayashi S.,Ashikaga Institute of Technology | Kamata A.,Ashikaga Institute of Technology | Watanabe T.,Northeastern University China
Acta Materialia | Year: 2015

Quantitative investigation of the grain growth and resultant change in grain boundary microstructure during high-cycle fatigue was performed to understand intergranular fatigue fracture in electrodeposited nanocrystalline Ni - 2.0 mass% P alloys by using FE-SEM/EBSD technique. Pre-fatigued specimens had an average grain size of 45 nm, a sharp {0 0 1} texture and a high fraction of low-angle boundaries and of twin, or Σ3 coincidence site lattice (CSL) boundaries. The considerable grain growth occurred due to the migration of low-angle boundaries induced by shear stress during cyclic deformation. The misorientation angle of those low-angle boundaries increased covering the whole surface of fatigue-fractured specimen. A certain fraction of low-angle boundaries was transformed into high-angle random boundaries resultant from grain growth during high-cycle fatigue. Those random boundaries which surrounded the grown {0 0 1}-grains were aligned along shear bands at almost 45° to the stress axis, and formed the diamond-shaped grain configuration, as reported in the literature on high temperature fatigue. The reported increase of the fatigue limit by nanocrystallization is likely reduced due to the cyclic stress-induced grain growth associated with the migration of low-angle boundaries composing nanograin cluster. Moreover, the random boundaries transformed from low-angle boundaries can be preferential sites for crack nucleation and propagation at the positions of initially formed shear bands during fatigue. © 2015 Acta Materialia Inc.

Saito H.,Ashikaga Institute of Technology
ASTM Special Technical Publication | Year: 2015

Roofing assemblies for wood frame houses are usually made up of a combination of roofing tiles and underlayments in order to avoid water leakage. However, on the actual construction site, fasteners (such as nails and staples) that pass through the roofing underlayment have the potential to make annular spaces that cause water penetration into sheathing boards of the roofing assemblies. This study describes the impacts of water penetration on moisture behavior at the sheathing board on the pitched roof of a wood frame house. Water spray tests for a roof structure that has roofing tiles are implemented to clarify water leakage through the gaps between the tiles. Additionally, rates of leakage through the interface between the roofing underlayments and the fasteners are determined by water penetration tests. Heat, air, and moisture (HAM) analyses of the water penetration through the roofing underlayment are demonstrated using climate data in a mild climate region. Results indicate that a vented cavity under the sheathing board should be used with roof assemblies having an impermeable underlayment (such as asphalt impregnated felt) in order to avoid serious moisture accumulation. Additionally, the results show that installation of permeable underlayment (such as polymer housewrap) is effective in preventing moisture accumulation in the sheathing board. Copyright © 2015 by ASTM International.

Zheng T.,Ashikaga Institute of Technology | Yamashiro M.,Ashikaga Institute of Technology
International Journal of Advanced Manufacturing Technology | Year: 2010

This paper proposed a novel quantum differential evolutionary algorithm (QDEA) based on the basic quantum-inspired evolutionary algorithm (QEA) for permutation flow shop scheduling problem (PFSP). In this QDEA, the quantum chromosomes are encoded and decoded by using the quantum rotating angle and a simple strategy named largest rotating angle value rule to determine job sequence based on job's quantum information is proposed for the representation of PFSP, firstly. Then, we merge the advantages of differential evolution strategy, variable neighborhood search and QEA by adopting the differential evolution to perform the updating of quantum gate and variable neighborhood search to raise the performance of the local search. We adopted QDEA to minimize the makespan, total flowtime and the maximum lateness of jobs and make the simulations. The results and comparisons with other algorithms based on famous benchmarks demonstrated the effectiveness of the proposed QDEA. Another contribution of this paper is to report new absolute values of total flowtime and maximum lateness for various benchmark problem sets. © 2010 Springer-Verlag London Limited.

Nagao K.,Ashikaga Institute of Technology
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2016

PURPOSE OF REVIEW: The concentrations of plasma-free amino acids, such as branched-chain amino acids and aromatic amino acids, are associated with visceral obesity, insulin resistance, and the future development of diabetes and cardiovascular diseases. This review discusses recent progress in the early assessment of the risk of developing diabetes and the reversal of altered plasma-free amino acids through interventions. Additionally, recent developments that have increased the utility of amino acid profiling technology are also described. RECENT FINDINGS: Plasma-free amino acid alterations in the early stage of lifestyle-related diseases are because of obesity and insulin resistance-related inflammation, and these alterations are reversed by appropriate (nutritional, drug, or surgical) interventions that improve insulin sensitivity. For clinical applications, procedures for measuring amino acids are being standardized and automated. SUMMARY: Plasma-free amino acid profiles have potential as biomarkers for both assessing diabetes risk and monitoring the effects of strategies designed to lower that risk. In addition, the methodology for measuring amino acids has been refined, with the goal of routine clinical application. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

Doi T.,Ashikaga Institute of Technology
IEEE Transactions on Magnetics | Year: 2013

This paper proposes a new quantum cellular automaton (quantum CA) for simulating macroscopic electromagnetic fields. The final target is to simulate the macroscopic electromagnetic fields on a quantum computer. In the proposal approach, Maxwell's historical model, which was explained the nature of electromagnetic fields in 1861, has been modified for a quantum CA model to simulate the electromagnetic fields. Then, a state transition rule for CA is determined by a strategy based on the quantum mechanics and the quantum computation theories. One of originalities of the proposed approach is that a system using quantum gates is superstructed to simulate magneto-static fields from currents. First, a modified Maxwell model for applying to quantum CA was shown. Second, by using the quantum computation theory, a quantum gate system to simulate the magnetic fields from currents was described. Finally, the proposed approach was applied to an example of magnetostatic field simulation. © 1965-2012 IEEE.

Pedroso D.T.,Ashikaga Institute of Technology | Machin E.B.,São Paulo State University | Silveira J.L.,São Paulo State University | Nemoto Y.,Ashikaga Institute of Technology
Renewable Energy | Year: 2013

The updraft biomass gasifiers currently available produce a gas with high tar content. For almost all downstream applications a substantial reduction of the tar concentration is required. The gravimetric tar concentration behavior in producer gas, obtained at a modified updraft fixed bed gasifier, was studied. The feedstock feeding system was modified respect to the traditional updraft gasification design in order to decrease the tar concentration in the producer gas; the material is feeding continuously through a conduit in the base of the reactor over the grate. The caloric power of the syngas obtained was slightly lower than the typical value for this type of reactor and the highest efficiency obtained for the woodchip gasification was 77%. The highest tar concentration obtained during the experiments was 1652.7 mg N m-3 during the first our of experiments, comparable with the smaller value reported for the updraft reactors, this value is reduced significantly after the stabilization of the gasification process in the reactor. The smaller value obtained was 21 mg N m-3. © 2013 Elsevier Ltd.

Nishimura T.,Ashikaga Institute of Technology
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability | Year: 2015

Safety of great deep repository design has been considered for high level radioactive waste disposal system in several countries such as Belgium, Canada, China, France, Germany, Japan, Sweden and Switzerland etc. The repository of the disposal is in most cases based on the aspect of multi-barrier system such as the natural barrier formation (i.e., host rock) and engineered barrier formation consisting of compacted bentonite. This study focuses on hydro-mechanical behavior of compacted sodium bentonite, and three different tests such as swelling test, one-dimensional compression test and constant vertical stress direct shear test were performed with suction control using vapor pressure technique. Also, a modified direct shear apparatus installed RH air circulation system was used in the direct shear test.

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