Acurate data of thermophoretic effect are necessary to adequately understand the behavior of particles in the field with temperature gradient. However, the gas flow of natural convection induced by temperature gradient prevents accurate measurements of the data in normal gravity. In this study, reliable data of thermophoretic velocity have been measured in normal gravity by suppressing the natural convection. Measurements were performed using two flat plates in closed system, which were placed horizontally and parallel to each other with the heated upper plate to form a temperature gradient in between. The effect of convection was suppressed to be negligibly small compared to the thermophoretic effect by setting the distance of the two plates very short. This distance was found to be an effective controlling parameter of convection. Meaningful data have been accumulated by changing parameters such as particle diameter and temperature gradient.

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Characterstic curves of tensile stress versus displacement (σ-δ curve) for loosely packed powder beds (high void fraction) containing fibrous materials have been measured to evaluate the mixing and unraveling states of fibers as a filler for composite materials by using a separable cell type tensile tester. The values of energy consumption calculated from the σ-δ curves were used to discuss the relationships among unraveling and/or formation of the fiber network state in the bulk powders and experimental conditions.
As a result, it has been shown that the unraveled degree of fibers could be evaluated by the calculated energy consumption for pulling out a single fiber from the powder bed.

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Behavior of particles on a vibrating plate was investigated both theoretically and experimentally. The applied vibration was 39kHz-ultrasonic, and the diameters of test powders were in the range of D_p50=0.5 to 46μm. The experimental results showed that all particles moved randomly on the vibrating plate. Fine particles, approximately 10μm or less in median diameter, formed many small agglomerates, which also vibrated with their shapes and sizes intact. The size distribution of agglomerates could be represented by a log-normal distribution, and the median diameter of agglomerates increased with decreasing primary particle diameter. The agglomeration mechanism was theoretically analyzed by use of adhesive and separation stresses in an agglomerate. The analysis showed that the agglomerate diameter was inversely proportional to primary particle diameter. Furthermore, it was shown that the compressive breaking load could be estimated from the analysis.

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