Tadao Fukuta

Microstructure and mechanical properties of newly developed SiC-C/C composites under atmospheric conditions

The purpose of this study is to investigate the relationship between its microstructure and bending strength of SiC-C/C (carbon-carbon) composites. By using the phenolic resin and carbon fiber bundle, the carbon fiber reinforced plastics (CFRP) precursor was prepared by employing filament winding technique. To modify the phenolic resin, the micro-sized glass fiber was added. The CFRP precursor was charred at high temperature at Argon atmosphere to obtain SiC-C/C composites. The matrix of composites was densified by resin impregnation done by cold isostatic pressing (CIP) method. The detail observation of matrix after charred revealed that when precursor resin was modified with glass fiber, the direction of thermal crack at matrix showed complex manner, while thermal crack at un-modified matrix only appeared along fiber direction. Because of the presence of complex thermal crack, the matrix of SiC-C/C composite showed high porosity at un-densified condition and effectively densified by CIP to promoting resin flow toward thermal crack. The bending and compression test results showed that bending strength and inter-laminar shear strength of SiC-C/C composites was increased by densification. Moreover, the fractured surface observations suggested that the presence of synthesized SiC nano-whisker at inter-laminar enhances the apparent shear strength due to mechanical bridging between laminar.

A handshake response motion model during active approach to a human

A handshake is an embodied interaction for displaying closeness through physical contact. In this study, we develop a handshake response motion model for a handshake during active approach to a human on the basis of analysis of handshake motions between humans. We also develop a handshake robot system that uses the proposed model. A sensory evaluation is performed for analyzing the time lag preferred by humans between the approaching motion and the hand motion generated by the robot system. Another sensory evaluation is performed for determining the preferred timing of a handshake motion that is accompanied by a voice greeting. The evaluation results demonstrate that the proposed model can generate a handshake response motion during active approach that is preferred by humans. Furthermore, the effectiveness of the proposed model is demonstrated.

Influence of Slurry Temperature and Gate Velocity on Injection Molding of Magnesium Alloys

In the present study, the influence of the slurry temperature and the gate velocity on the apparent density of molded products was investigated using a thixomolding machine and a die having a rectangular parallelepiped cavity. Magnesium alloy of AZ91D was injected into the cavity through a rectangular gate. The gate velocity was varied from 0.4 m/s to 6.0 m/s and the slurry temperature was changed between 853K and 903K, respectively. The die temperature was fixed at about 513K. The results were as follows. The apparent density of the molded products at a constant gate velocity was decreased gradually with an increase in the slurry temperature in cases the slurry temperature was lower than 863K, however, it decreased suddenly at around the slurry temperature of 873K, and then it took an almost constant value when the slurry temperature was over 873K. The apparent density of the molded products at a constant slurry temperature was decreased greatly with an increase in the gate velocity in the case the slurry temperature was over 873K, however, it decreases slowly as the gate velocity increased for cases the slurry temperature was under 863K.

Quantitative Evaluation of Copper Clustering Process by Lattice Monte Carlo Simulation.

In this study, we simulate nanoscale copper precipitation process based on the vacancy jump model using Lattice Monte Carlo (LMC) method, where an activation energy is calculated from the first neighboring interaction model. We confirmed that status of copper clustering at temperature of 300 K is different from those of 600 K and 900 K at the same potential energy decrease, and copper clusters are formed more rapidly at higher temperature. We obtained a fact that process of copper clustering consists of the two phases which are formation phase, and coalescence and/or absorption phase.