In order to evaluate the shape characteristics of a particle in more detail, the characterization of the particle projection was discussed by a pair of shape indices: the macroscopic shape index δ and the microscopic one ζ.
In the present work, δ and ζ were defined as follows. δ is the degree of circularity of the equivalent ellipse which has the same projection area and the same ratio of the maximum length to the breadth as the original particle projection, and ζ is the ratio of the perimeter of the particle projection to that of the equivalent ellipse. It expresses the degree of roughness of the particle periphery. Several kinds of model pictures and projections of granules of different shapes were characterized by the shape indices.
As a result, it was concluded that the pair of shape indices, defined in the present paper, could be one of the effective measures for the shape characterization of particle.

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At present, there is no reliable method available for determinating the compaction characteristics of ultrafine particles, the sizes of which ranges from several to one hundred manometers. In this paper, the authors propose the centrifugal compaction method to evaluate the compaction characteristics of the ultrafine particles by applying the self-compressive stress by centrifugal force in a packed powder bed. With such a system, compressive strains can be determined with good reproducibility as a function of centrifugal force. The relationships between compressive strain and centrifugal force for ten kinds of ultrafine particles, such as Fe, Co, Al, SiO₂, Al₂O₃ and TiO₂ were found to be divided into two categories. One category can be written as a linear relationship between the logarithm of compressive strain and the logarithm of centrifugal force, while the other can be described by a linear relationship between compressive strain and the logarithm of the centrifugal force.

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This investigation is to study the aggregate process and the structure of particles in high concentration slurry using slip casting. The aggregate state of the particles in an alumina slurry were discussed on the basis of rheological and sedimentation behavior. From these properties, this slurry could be classified into three states of aggregated structure as a function of the dispersant concentration. The structure of these slurries was observed directly by the freeze drying technique. The behavior of spinability of these slurries was discussed on the basis of this structure.
Simulation of the aggregate process of particles was done as a function of cohesion probability. Then, the relationship between the dispersion state of particles and the cohesion probability were showed.
From the results of the measurments, the dispersion state of the particles in these slurries were determined.

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The surface nature of quartz powder pulverized in a hexane solution of cetyl alcohol or octadecyltriethoxysilane by means of a ball mill was investigated. The original quartz powder showed itself to be hydrophilic since it dispersed in water as well in an immiscible mixed dispersive medium. While quartz pulverized in a hexane solution of cetyl alcohol was hydrophilic since it dispersed in water, for an immiscible mixed dispersive medium, guartz after pulverization for 8hrs. dispersed in water, but that after pulverization for 16hrs, or longer, dispersed in hexane. These pulverized quartz powders were much more hydrophobic than the original quartz powder. The quarts powder after pulverization in a hexane solution of octadecyltriethoxysilane showed that the one after pulverization for 24hrs, dispersed in water, while the one after pulverization for 32hrs., or longer floats on water. Therefore, these quartz powder were found to be hydrophobic, but for an immiscible mixed disperse medium, the ones after pulverization for 8hrs, or longer, dispersed in the hexane phase. The characteristic absorptions due to the surface group on the quartz powder after pulverization for 64hrs. were observed in the infrared adsorption spectra. The evolved vapors of the surface group were observed in their pyrolysis curves. The increase in carbon content was found to be accompanied with an increase in surface area due to pulverization. Accordingly, the quartz powder was found to be surface-treated effectively due to pulverization. The quartz powder pulverized in the hexane solution of cetyl alcohol was hydrophilic, more hydrophobic than the original quartz powder. This is due to the formation of the equilmol OH-group as that of the alcoxy-group.

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The solubilites of phenylbutazone polymorphs, pure α, β and δ, were measured over a temperature range of 35°C, from 50°C to 15°C. Both the Van't Hoff plots of lnX₂ against 1/T and the Hildebrand plots of lnX₂ against lnT are nonlinear, where X₂ is the mole fraction solubility at an abslute temperature, T. The data were treated by multiple regression analysis according to the equation: ln(solubility)=(-Q/R)(1/T)+(b/R)lnT+c, where a, b and c are constant and R is the gas constant. From a, b and c, the heat of solution ΔH*_2(soln) may be calculated e. g. ΔH*_2(soln)=a+bT, and ΔC_p=b, where ΔC_pis the difference between the heat capacities of the liquid and the solid forms of the solute. Also, the heat of dissolution, ΔH_2(diss), and dissolution activation energy, E_a, for these polymorphs were obtained by using the initial disolution rate at various temperatures. Their ideal mole fraction solubilities (α₂) were calculated from the heats of fusion and the melting points of these polymorphs. The activity coefficient, γ₂, the partial molal heat of mixing, ΔH_2(mix), and the differential heat of solution, ΔH_2(soln) may also be calculated from the heat of fusion, the activity coefficient, and the mole fraction solubility. The relationships between these ΔH*_2(soln), ΔH_2(diss) and E_a were discussed.

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A novel Emulsion-Solvent-Diffusion method was developed to agglomerate the crystals of poorly compressible pharmaceuticals during crystallization without using any binder for improving direct compressibility. In this process, crystallization occurred in the dispersed aqueous droplets of the drug in agitated ethyl acetate by the water diffused out of the droplets. The tensile and shear tests of the resultant agglomerated crystals proved that they were easily flowable and packable. The fracture strength of compaction (a tablet) of agglomerated crystals was much stronger than that of unagglomerated ordinal crystals, indicating the improved compressibility of agglomerated crystals. The agglomerated crystals were easily compressed into a tablet without capping, as proved by their much reduced capping ratio compared with that of ordinal crystals.

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This study deals with a surface modification method in a dry powder/powder handling system. The method is a dry impact blending method which is capable of changing an interactive mixture to composite or encapsulated particles. The effect of powder properties in this method was observed in terms of SEM observations.
Nylon 12 (5.0μm, positive charge) and polyethylene (5.0μm, negative charge) were used as core materials. Polymethylmethacrylate particles (0.4μm) having a positive or negative charge as wall materials were used for each core material for studies on the effect of electrostatic conditions in dry impact blending preparation.
No remarkable differences in the preparation of encapsulated particles were found between the combination of identical charged powders and the combination of opposite charged powders. Namely, surface appearances of the encapsulated particles were the same as those in SEM observations. In another experiments, silica particles (0.6μm) as the wall material and polyethylene (2-10μm) as the core material were used for studies of adhesion mechanism in the preparation.
Silica particles were homogeneously embedded into polyethylene core surfaces because of the mechanochemical effect by hard impact force. Finally, the silica mono-particle layer coated powders were prepared by embedding adhesion mechanism.
It was concluded from these results that one of the important factors for creating surface modification particles is the strength of the impact force in producing mechanochemical effects.

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A key in design and operation of the direct reduction shaft furnace is to prevent iron ore pellets from clustering. A new rotating type shear tester was developed to measure the shear strength of the pellets during reduction and to relate it to the flow condition. The size of the cell is 144mm O. D. and 80mm I. D., and the pellets in the cell are reduced by using CO gas at the temperature elevated to 980°C. The maximum load on the cell is 3.40kN for consolidation and 0.86kN during shear. The measured shear strength of the reduced pellets was from 40 to 70kPa, and it was decreased approximately to half by shearing continuously during reduction.

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The optimum, operaing conditions for compounding a fibrous filler within a polymer matrix were studied. Electroconductive carbon fiber was mixed with fine polytetra-fluoro-ethylene (PTFE).
The particles size in the granulated mixture, the optimum mixing time both premixing for disintegrating the agglomerates of the matrix and agitation for dispersing the filler into the matrix powder, and the preforming pressure of the mixture were discussed according to the mechanical and electrical properties of the prepared composites. It was shown that the resistance of the sintered composites greatly depended on fiber concentration and preforming pressure.

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Continuous kneadings of composite conductive plastics were performed employing two kinds of electric conductive fillers, nickel coated glass fiber and stainless steel fiber, which have different fibrous strengths.
Between the two kinds of fillers, the differences in the dispersion state and breakage state of the fillers in a matrix resin were investigated, and their influence on the electric conductivity of the kneaded material was estimated.
In addition, it was suggested that the total number of paddle revolutions during residence time of kneading material was a factor affecting the dispersion and breakage states of the fillers.

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