Shigeo Miwa

Reliability Engineering. Study of Grading Mechanism by the Markov Type Grinding Model. Application of Grinding Matrix.

The grading technology with crushing and grinding is necessary to produce materials like natural river sands and to obtain sub-micron powders for the materials for electronic devices and surface lining. It is known that grinding operation is the representative method, and it may be possible to grade particles. But in the field of grading particles, it is not common to study the grading phenomena in the process of grinding by the time, especially to study the particle size distribution of coarse powder in the closed circuit grinding system. Based on the analogy of sieving model by the Information theory, this paper led to the result by the time dependence equation in the grinding process, and it showed that the obtained equation has similarity to that of grinding Matrix. Moreover, the grading mechanism of the sands was figured out by verifying the equation of the closed circuit grinding system, using Onumas data and graded sands or booming sands. And also, the paper suggests that applying another technology is very effective to save energy at the point that the transfer from volume grinding to surface grinding had occurred. And the examination of the materials could be useful in making a plan to produce the range of the particle size.

New modifications of Pb5Nb4O15 and Pb3Nb2O8

The formation of Pb5Nb4O15 and Pb3Nb2O8 was studied using the powders prepared by the simultaneous hydrolysis of lead and niobium alkoxides. A new metastable modification of the former compound crystallized at low temperatures from an amorphous material. It had a cubic unit cell with a = 1.0674 nm. Two new modifications of the latter compound were found to exist. The metastable modification was formed by the solid-state reaction of cubic Pb5Nb4O15 and orthorhombic PbO. The crystal structure had a cubic symmetry with a = 1.0715 nm. The low-temperature modification was formed by transformation of the cubic phase. It was classified into monoclinic system with a = 1.2903 nm, b = 0.7394 nm, c = 3.3092 nm and β = 115.96°.

Frequency spectrum of the noise of flowing particles on an inclined plate.

2次元流動粒子群から発生する音の諸量と流動状態との関係を検討した.流動音を構成する2粒子衝突音に基づく粒子群流動音音圧波形の推算法を提出した..それによる周波数スペクトルは, 測定スペクトルとよく一致しており推算法が妥当であることがわかった.流動粒子群の流速と流動音の音圧および流動音の周波数と粒子径の間には, 簡単な関係があり, 流動音の測定により流量と粒度の同時計測が可能であることがわかった.さらに流動音の周波数スペクトルから, 流動粒子の平均衝突回数および粒子間平均距離に関する知見も得ることが可能である.