For storage of industrial disposal and carbon dioxide, underground caverns are increasingly necessary due to the shielding effect of rock masses. Effective shielding properties of underground caverns are highly demanded for protecting surface environment. Thus, developing quantitative evaluation and long-term monitor methods for the properties of rock masses are indispensible. Additionally, shilding effects of rock masses are closely related to ground water flow through rock discontinuities, studies on the mechanism of discontinuity behaviour in rock mass based on three dimentional monitoring will be extremely useful for the safty control of underground caverns.

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変形率変化法 (DER) は理論的根拠は薄いが, 簡便でかつ興味ある地圧計測法として注目されている. DRAは岩石の変形過程における内部構造の変化と, 密接な関係を有すると考えられる. 岩石の内部構造を調べる一手法として, 従来より超音波伝播時間計測が用いられているが, ここでは10^-2nano-secの精度で伝播時間を計測できる装置により, あらかじめ人工的に応力を記憶させた太平洋炭鉱産砂岩に, 載荷軸に垂直な面内の伝播時間計測とDRAを同時に試みた.
その結果, 伝播時間が高精度で計測され, 伝播時間と横ひずみ挙動との間に, 比較的良好な対応が認められた. また, 伝播時間は記憶応力付近で大きな変化を示し, その点はDRAで得られた屈曲点とほぼ一致した. すなわち, 高精度の超音波伝播時間計測は, 岩石の内部構造変化を詳細にとらえることができ, 今後コアを用いた地圧計測を発展させる上で, 有効な計測手段となり得ることがわかった.

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The purpose of this study is to prove the effect of internal pore pressure on unsteady-state gas flow in coal. Practically, the gas permeation model of coal which consists of the gas permeable and non-permeable crack network was proposed. Then the numerical simulations of gas permeation by this model were carried out by changing the parameters such as inlet pressure in the crack network, confining pressure against coal, closing probability of cracks, etc.
The results of these simulations on fluctuations of unsteady-state gas flow were in agreements with the experiments of gas permeation of coal. From these considerations it was found that the above gas permeation model was accurate enough for practically. Moreover, the results of the simulations on unsteady-state gas flow in coal gave an explanation to the deviation from the Darcy's law in the relationsbetween gas flow and difference pressure.

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The purpose of the present study is the effect of crack orientation on the gas permeability and gradient of gas pressure in coal. Practically, the model of anisotropic crack network was applied to the computer simulations under the state of an uniaxial compressive stress. Additionally, the simulations of gas permeation and gas pressure were investigated by setting the normal distribution as the frequency distribution of crack orientation. The results of these simulations were as follows.
1) The anisotropy of crack orientation in coal is very effective on gas permeability, and the gas permeability in the orientation of maximum principal stress is higher than that of minimum principal stress.
2) In the anisotropy crack network, the gas permeable cracks of the direction of minimum principal stress close at their neck. Consequently, gas flow is intercepted by the difference stress between an external stress and gas pressure in the cracks of the direction of minimum principal stress become high.
3) The occurrence mechanism of a gas outburst is explained by applying the bending theory of circular plates to the anisotropic crack network saturated with high pressures gas.

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A drilling model was previously proposed by Okubo and Nishimatsu (1991), and a computer program which had capability to simulate continuous drilling-process was also developed bythem. The model which consists of a drill-body, a piston, a rod and a bit was analyzed based on the one-dimensional stress-wave theory. A force-penetration curve with hysteresis was assumed for bit/rock interface.
In this study, comprehensive simulation for a heavy drifter of 150 kg-class was carried out. Special care was taken to clarify the effect of thrust on rock-drilling performance such as penetration rate, piston stroke, piston velocity, elastic wave in rod. Calculation was performed under more than two-thousand conditions changing thrust, bit/rock interface parameters and attenuation rate on drill/rod interface.
An appropriate thrust, Fth_apl, was proposed as follows; F_th-apl≅A_back·P_back-A_front·P_front, Where ‘A’ denotes effective cross-sectional area, and ‘P’ pressure. Subscripts ‘back’ and ‘front’ indicate back and front cylinders, respectively.

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In production of super-clean coal by any physical coal-cleaning process, the feedcoal must be micronized to liberate finely disseminated mineral matter. One of the most efficient devices for micronizing coal is a stirred ball mill. Using the laboratory mill with a relatively high media loading (80 % filling), small grinding media (less than 1 mm diameter), and three coals, effects of some parameters such as media size, stirring speed, and pulp density on the grinding of coals have been studied. The product with a mediansize of 2μm was obtained at a suitable operating conditions with a mean residence time of 6 min. The wear loss of the grinding media and vessel depended strongly on the amount of the hard minerals disseminated in coal, such as quartz, pyrite and iron oxide.

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It is usual to notice the size distribution of particles in simulations studies ofpowder processes. On the other hand, specific surface (Blaine value) has been applied as a standard for describing product quality particularly in cement industry. Therefore, in order to transfer experimental resultsobtained in a laboratory to the data for an industrial use, it is necessary to estimatethe specific surface from the size distribution data. For this purpose, the authors have successfully applied an inferential method with an artificial neural network (ANN) to the size distribution based calculation of the specific surface.

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0.5mol/dm³の塩酸を用い, 333Kの温度でヘマタイトならびに塩化第2鉄をそれぞれ浸出助剤として比表面積3m²/gの黄銅鉱から銅の浸出実験を行った。ヘマタイトを用いた浸出実験では, 黄銅鉱を24時間浸出した場合, 銅収率が約75%となるのに対して, 塩化第2鉄では65%となる。ヘマタイトを用いた場合の銅収率は, 浸出助剤無しの場合の約2倍かそれ以上となる。浸出後の残査に硫黄が析出するとき高い銅浸出が達成される。特に, ヘマタイトを用いる方が塩化第2鉄を用いるよりも硫黄析出が多い。したがって, ヘマタイトは黄銅鉱の塩酸浸出において効果的助剤といえる。

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In order to clarify the behavior of the metallurgical phases in the oxidation zone of the QSL lead smelting process, the phase equilibrium between the metallic lead and the PbO-FeO_x-CaO-SiO₂or PbO-FeO_x-CaO-SiO₂-ZnO slag was investigated at 1, 423 K. The EMF method using a solid electrolyte with calcia-stabilized zirconia was applied to measure the oxygen partial pressure in the system. The oxygen pressure increases with increasing PbO content in the slag. The PbO activity and activity coefficient estimated from the oxygen pressure increase with the addition of CaO into the slag. However, the PbO activity is slightly affected by the FeO_xcontent at constant PbO concentration in the experimental region. Itwas clarified that ZnO gives a small effect to the activity coefficient of PbO in the PbO-FeO_x-CaO-SiO₂-ZnO slag. The partial pressure of the PbO component in the gas phasecalculated by using the PbO activity coefficient in the slag isconsiderably small compared with that of metallic lead.

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ZnGa₂O₄螢光体の発光特性およびその発光機構を調査する目的で, それを固相反応により合成した。試料粉末の生成相, 発光特性, ドープ特性をX線回折法(XRD), 発光-励起スペクトル(PL)の測定, 電子スピン共鳴(ESR)の測定などから実験的に検討した。254nm励起下で, ZnGa₂O₄螢光体は450nmをピークにして, 広いバンドの青色発光体特性を示した。合成した螢光体を弱に還元性雰囲気にして処理すると発光強度が大きく増大した。また, Mn²⁺ をドープしたZnGa₂O₄螢光体は504nmをピークにして, 強くて細いバンドの緑色発光特性を示した。そのとき, Mn2+のドープ量を0.006%モルしたZnGa₂O₄螢光体が最大発光強度を示した。

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