The flowability of a cohesive powder was represented by a ratio of the unconfined yield stress to the unit weight of a bulk solid. An expression of the flowability was studied on the basis of a power function which was assumed between an applied force and a cohesive force at the contact of particles adjacent to each other.
The expression was supported by the results of shear tests for 17 kinds of dry cohesive powders which had a range of 2 to 40μm in the specific surface diameter. It's diameter ratio of 1.4 to 5.5. The flowability was expressed in terms of the specific surface diameter of the powder, the major consolidation stress and two experimental coefficients. The coefficients seemed to be proper for the powder material.

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Solubilities and initial dissolution rates of indomethacin polymorphs, pure α and γ forms, in water at various temperatures were determined, and from these parameters and temperatures, the heats of solution, ΔH_2(soln), and heats of dissolution, ΔH_2(diss), of these polymorphs were obtained. The activities of these polymorphs in water were calculated using the ideal solubility equation, and the activity coefficients were also calculated from these activities and mole fraction solubilities. The heats of solution, ΔH_2(soln), of these polymorphs were evaluated using melting points, heats of fusion at the melting points, mole fraction solubilities and activation coefficients. Comparing ΔH_2(soln) with ΔH*_2(soln) or ΔH_2(diss), it was suggested that ΔH_2(soln) corresponded to ΔH_2(diss) rather than to ΔH_2(soln).

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Injecting air into a atandpipe with an orifice, the aeration rate, the flow rate of granular materials and the air pressure distribution in the standpipe are measured. The relationship between the aeration rate and the flow rate of granular materials for different particle diameters, orifice diameters and the locations of air injection are examiend, and the following conclusion is drawn.
The flow rate of granular materials can be adjusted by aeration. For air injection closer to the orifice and for a smaller particle diameter, a higher flow rate of granular materials can be expected. These relationships are explained by the modified de Jong's and Crewdson's equation, and the experimental data are correlated by a computable equation with an error of ±30%, except for some of small particles for which these relationships are influenced by the adhesion of the particles. For small particles, these relationships are improved by aeration, but are insufficient.

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Thermal stability of a cylindrical dust deposit subject to the time periodic variation of ambient temperature is investigated, where the cylinder is symmetrically heated by an exothermic zero-order chemical reaction. (i) The dimensionless heat balance equation is solved numerically. At a larger value of frequency, the same criterion can be used as that proposed for a constant ambient temperature. However, at the smaller range of frequency, both the ignition tempertaure and the induction time are decreased with decreasing frequency and increasing amplitude. (ii) By applying an approximation to the term of heat generation, the heat balance equation is solved analytically. The critical values of the dimensionless groups obtained from the above simulation corresponding to the infinite induction time are substituted into the analytical solution, leading to an empirical criterion used to predict the ignition temperature. A graphical method is also illustrated. By comparing of the calculations with published experimental data, this criterion is found to be widely applicable for ambient temperature variations in stepwise as well as periodical ways.

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