Measurements of the pore structure of alumina (Neobead C) were investigated. The pore structure was measured by nitrogen adsorption-desorption and mercury penetration technique. The pore size distribution was calculated from the nitrogen adsorption-desorption isotherm data by the Cranston-Inkley method, the Barrett-Joyner-Halenda method and the Modelless method.
The surface area was determined by the B. E. T. method and the t method (the thickeness method). Result obtained were as follows: (1) The sample M (d_p: 605 microns) was shown to be smaller amounts of adsorption of nitrogen over whole range of the relative pressure than that of the powdered sample S (d_p: 58.5 microns). It is considered that the difference of the time consumed for a equilibrium adsorption, depends on that of particle size. (2) The surface area S_BET obtained by B. E. T. method coincided well with the surface area S_t by the t method for powder sample S. (3) From the fact of plotting on a adsorption volume against the relative pressure being linear in the low relative pressure range, it is suggested that the multilayer of gas adsorption must be formed at the lower relative pressures. (4) The pore size distribution calculated from the nitrogen adsorption-desorption isotherm by each method was not so much different with each other. (5) The pore size distribution calculated from the nitrogen adsorption isotherm was largely different from that of the nitrogen desorption isotherm. The pore size distribution obtained by the mercury penetration method was markedly different from the branch of compression or the branch of depression in the penetration curve. (6) The pore size distribution of the aggregate of glass beads measured by the mercury penetration method was similar to that of alumina.

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The thickness of a liquid bridge which induces an adhesive force between powder particles under high water vapor pressures was studied. For this purpose, adhesive force generated at contact points between spherical and plate specimens of Pylex glass was measured by using an electrobalance, then a pore size distribution calculated from an isotherm of water vapor desorption on Vycor glass at 10°C was compared with that obtaind from the nitrogen desorption isotherm at -196°C.
An adhesive force appeared at relative water vapor pressures (P/P₀) above 0.4, and it increased considerably in the P/P₀ range 0.65-0.75. Moreover, a capillary condensation occurred in a hollow Pylex capillary at P/P₀ above 0.6. From the above results, a liquid bridge at contact points between particles is considered to be formed above P/P₀ 0.6. The thickness of the liquid bridge at P/P₀ 0.6 is calculated to be 37Å by adding “multilayer thickness” to the “Kelvin radius”. The average radius of the Vycor glass, calculated from a nitrogen desorption isotherm, was 20Å, whereas the average radius calculated from the water vapor desorption isotherm was 30Å. Such difference between the pore radii will be attributed to assumptions that the surface tension for the adsorbed water layer is equal to that for a bulk water and that the angle of contact is zero. Considering these facts, it is estimated that the thickness of the liquid bridge at P/P₀ 0.6 is within the range of 28-37Å.

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In order to determine the critical separating condition of an inclined disc separator with a spiral scraper, a series of experiments was carried out by using mixtures of spherical (alumina spheres) and non-spherical (silica sands) particles under various disc inclinations (3-13°) and rotating speeds (1-50rpm). Critical conditions in terms of the disc inclinations, rotating speeds and friction factors between non-spherical particles and the disc surface were discussed on a basis of a single non-spherical particle motion in the separating zone of the separator.
The separation efficiency increased exponentially with the values of a dimensionless group (nr_θc d_pi²ρ_pi/F_i) as a function of the radial non-spherical particle number passing through the separating zone below the critical values of the disc inclination and rotating speed, where d_pi, ρ_pi and F_i are average particle diameter, particle density, and feed rate of non-spherical particles, respectively, and n is speed of rotaton, r_θc radius vector at θ=π. The fraction of non-spherical particles sliding into the products of spherical particles was approximately calculated by introducing the distribution of the sliding friction coefficient of non-spherical particles on the separator surface.

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In the first report, we showed that the value of the vertical pressure of granular materials on the bottom of the model bin increases with the rate of filling. The reason for these phenomena is that the structure of deposition for granular materials changes with the rate of filling. This paper describes the correlation between the rate of filling and the bulk density of granular materials.
The value of bulk density of granular materials was measured under different filling rates with different volume glass cylinders and different heighs of falling. Four kinds of granular materials were used: two kinds of glass beads and two kinds of standard sands.
One of the experimental results is that the value of dulk bensity decrease with the rate of filling. However, the value of bulk density is affected by other factors, in particular the process of falling and deposition of granular materials.

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Binary mixtures of sulfisomidine and lactose particles were suspended in chloroform and were agglomerated with buffered sodium phosphate solutions (pH7.4). The agglomerate particles at 1.5min residence time were fractionated by sieves at six levels according to the particle size. The content ratio of sulfisomidine of the each fraction to the original feed powder was determined. The significant variance of the content ratio with the particle size of the agglomerates was found, which strongly depended on the particle size of lactose and the mixing ratio of sulfisomidine.
With increasing the particle size of lactose and decreasing the mixing ratio of sulfisomidine, the content ratio in the agglomerate with over size (+12mesh) decreased, which indicates that the larger lactose particles are included more in the agglomerate with increasing the particle number of lactose in the system. The content variation disap Peared gradually when the agglomerate particles growing in the course of agitating the suspension. This suggests that the more preferential adhesion may occure between the larger lactose and sulfisomidine particles, leading to the formation of the agglomerate enriched with lactose.

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