Powdered alumina (A), magnesia (M) and silica (S) were selected among the metal oxides used in the ceramic industry to study how the bulk density and tensile strength of green body change with heat treatment. It seems that a desorption temperature of the surface hydroxide layer (T_OH) and the melting point (T_m), which are inherent to each powder, correlate with the change in green body characteristics. The results are as follows:
1) The tensile strength of green body with the same porosity decreases until 0.3Tm as the heat treatment temperature increases; above this, it increases. This temperature (0.3Tm) is equivalent to the one at which surface diffusion begins.
2) The hydrophilic group of the surface decreases remarkably when the powder is heat-treated over T_OH, and the adsorbed water in the powder decreases in the same atmosphere. Therefore, the density and strength of the green body are affected differently by the same humidity condition.
3) The density and strength of A, M and S are not changed in the same way by heat treatment when green bodies are fabricated at the same compression force. This may be because 0.3Tm is lower than T_OH for S but higher for A and M, or because the remainder between these two temperatures is different in degree for each powder.

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The Solids mixing process has been regarded as a probabilistic phenomenon which involves both convective and diffusive mixing. However, it is difficult to distinguish or separate these two mixing mechanisms —convection and diffusion— in an actual mixer.
Akao and Fan proposed a new approach called “the synthesis of a mixing system” to overcome the aforementioned difficulty. First, they separated the two mixing mechanisms as a unit operation and then constructed respective models, lastly synthesized a model mixer on the basis of these models. They reported that the approach could consistently systematize the solids mixing processes from a simple model mixer to a practical one.
The most fundamental model mixer can be realized by feeding a striated mixture, obtained from the convective mixing model, to a diffusive mixing model (probabilistic branching model). The mixing effectiveness of this mixer has been examined by increasing the number of strata in various ways. It was reported by Fan et al. that the number of strata affects the effectiveness.
However, it is recognized here that the mixing effectiveness depends not only on the number of strata but also on the pattern of the striated mixture. This paper presents the pattern that can most rapidly attain a completely mixed state. It can be concluded that an optimal feeding is the particular striated one obtained from the convective mixing model by folding operations. The optimal feeding is characterized by the repetition of the unit pattern, such as black, white, white and black. It is shown that optimal feeding requires only a few transitions to attain the completely mixed state although the others require much more. This result is of practical significance in designing a mixer.

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The pressure drop due to horizontal-to-vertical and vertical-to-horizontal bends was measured in an experiment on pneumatic conveying. The ratio of the additional pressure gradients at the inlet and outlet of the bend is defined as the factor showing the effect of the bend on the pressure drop. The experimental conditions are as follows:
Pipe diameter (I. D.)=40mm
Bend curvature to pipe diameter ratio=12.3, 20.5
Particle size=2.9mm (Large particle), 0.18mm (Small particle)
Loading ratio defined as the particle to air mass ratio=2, 5, 8
Bulk air velocity=15, 20, 25m/s
Experiments were also made on particles with a mixed size of the above two kinds. The results are summarized as follows:
(1) The effect of mixed size on the pressure drop is negligible in the constant velocity region of a straight pipe.
(2) The pressure gradient ratio π decreases as the loading ratio increases. The ratio π is always larger than one for the large particles. The ratio π becomes smaller than one for the small and mixed particles at a large loading ratio. This is due to the fact that those particles tend to slide on the bend pipe wall.
The ratio π of the mixed particles shows the same tendency as the large particles at a low loading ratio and the same tendency to the small particles at a high loading.
(3) In the case of large particles, it is possible to calculate the particle velocity at the bend outlet and pressure drop after the bend by using the data of the additional pressure drop at the outlet.

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The flow properties of particles and powder were measured by the improved direct shear tester. This shear tester has the following features.: (1) the actual vertical stress acting on the shearing surface can be measured. (2) PYL can be measured by constant volume shearing as well as by constant vertical stress shearing. (3) WYL also can be measured easily.
From the experimental results obtained using this shear tester, the availability of this tester was proved, and the importance of measurement of actual vertical stress acting on the shearig surface was confirmed.

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The distributions of solids pressure were measured on the vessel wall and in the particle layer at static and flowing conditions by using two- and three-dimensional hoppers and cylinders. The following results were obtained:
1) The pressure distributions of bulk solids in the storage vessels are not uniform in the horizontal direction nor in the vertical one.
2) The ratio of the horizontal to the vertical pressure changes at positions in the vessels.

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