Recently, international mutual recognition of engineering register becomes a big topic in the world. With this problem arising abruptly also in APEC area in 1996 as a turning point, the renewal or the reconstruction of engineering education has been actively discussed in Japan. This paper introduces the present situation of engineering educational reform in Japan performed by working groups in the Dean's Committee of School of Engineering of so-called the Eight National Universities, the Foundation Committee for Japan Accreditation Board for Engineering Education, and the University Council in Monbusho.

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This paper summarizes the theoretial and experimental comparison of physical characteristics of thick and hard rock strata which lies above wall type faces in The Republic of South Africa (Sigma Colliery) and Japan (Kushiro Colliery) and its effect to restrict surface subsidence. The difference of subsidence together with goaf solidification by the nature of rock strata is analyzed. When it is compared with the Dolerite case at an elastic modulus of 70 × 103 MPa, which is known that the 200 m face length is a minimum criteria for stable long wall operation, it is found that the face operation by the face length of more than 100 m with the hard and thick rock strata at an elastic modulus of 15 × 103 MPa will be an appropriate standard for Kushiro case. This is because of the occurrence of hanging phenomenon and its periodical heavy goaf flushing, when face standards, particularly face length is inappropriate. Thus, face design considerations are largely affected by the existence of thick and hard rock strata found in Dorelite (South Africa), Pocahontas Sand Stone (USA), Coalcliff Sand Stone (Australia) and Harutori Conglomerate/Sandy Shale (Japan).The author also indicate that the existence of very hard and thick rock strata above face can be pragmatically utilized to avoid sea water penetration in shallow coal mining district by way of applying comparatively shorter face length which will not allow sea bottom subsidence. As the results of analysis, design considerations for wall type mining, particularly face length is offered to suit various mining conditions.

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In order to investigate the length of cracks developed by stress corrosion and cyclic fatigue and the time to failure under cyclic loading in compression, the equations proposed by Costin et al. is estimated from the results of creep and fatigue tests for OGINO tuff, KIMACHI sandstone and AKIYOSHI marble. Under the fatigue tests at cyclic frequency of 1 Hz, the ratio of the length of crack due to stress corrosion to the total one increases with increasing upper stress ratio. The length of crack due to cyclic fatigue is proportional to the exponent of cyclic frequency of stress, and the time to failure is affected by it. Also, in case that the length of crack due to stress corrosion occupies the most part of the total crack length, the increase in the time to failure is smaller with decreasing frequency. The time up to failure is longer as the stress amplitude decreases, but below a given ratio of stress amplitude, it is smaller with decreasing the ratio of stress amplitude. Also, the ratio of stress amplitude, at which the time to failure takes a maximum value, and the length of crack due to cyclic fatigue are smaller as the ration of stress amplitude decreases.

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This research has introduced a new approach for the numerical simulation of chemical reactions and processes. We call this method as the "Box-Contact" method. The empirical method of numerical simulation usually uses differential equations based on the following assumption；the nature can be expressed as it is continuum and keeping continuity in fields. However especially in the field of material science and engineering, a homogeneous and continuous field can rarely appear. For example, a TV is constructed by various different material parts such as a main frame, switches and a display glass. It suggests that we could not treat the each phenomenal behavior of chemical reactions or processes using differential equations. Because a "TV" phenomenon is processing in the discontinuous field, and can divide simpler distinguished processes. Therefore, we made a concept of "Box-Contact" method in which a phenomenon was divided to kinds of processes and treated as "Boxes". The definition of the "Box" depends on the observational resolution. Each boxes have each simpler processes. Then we associated the "Contact" relations with each boxes to simulate the phenomenon. In this study the adsorption in a separation is demonstrated by using Box-Contact method as an example. The result shows that this method is useful to elucidate the mechanism in the chemical reactive phenomenon, which is not attainable by using ordinary differential equations simulations.

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It is important to clarify the flocculation phenomena for the mineral processing such as waste water treatment. For this object, experiments on the flocculation phenomena have been carried out using quartz and fluorite particles which are negatively and positively charged in distilled water, respectively. In the present study, suspensions containing the particles smaller than 4.6μm (fine particle suspension) and larger than 9.3μm (coarse particle suspension) are prepared to understand the flocculation phenomena of the mixture of fine quartz-fine fluorite particles, fine quartz-coarse fluorite particles, fine fluorite-coarse quartz particles and coarse quartz-coarse fluorite particles in the different pH values. It is found that fine quartz and fluorite particles homo-flocculate at pH about 2 and pH over 11, while coarse quartz and fluorite particles do not homo-flocculate at all pH range. In the experiments conducted with the mixture of fine quartz and fluorite particles in equal proportion, the electric gravitation between them has led to the hetero-flocculation at all pH range. When fine quartz and coarse fluorite particles are mixed, it is considered that the hetero-flocculation such as coarse particles are coated with fine particles would occur at all pH values. Besides, homo-flocculation of fine quartz particles can be also observed at pH about 2. In case of the mixture of fine fluorite and coarse quartz particles, the hetero-flocculation such as coarse particles are coated with fine particles and homo-flocculation of fine fluorite particles are supposed to occur at all pH values and at all pH values, respectively. Remarkable flocculation phenomena can not be seen in mixing coarse quartz and coarse fluorite particles at all pH values.

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Carrier flotation of ultrafine wolframite (-5μm) was investigated using coarse wolframite (37∼53μm, etc.) as carriers and sodium oleate as collector. Effects of some factors on the carrier flotation of ultrafine wolframite were studied. It was found that the recovery of ultrafine wolfromite was significantly increased from about 41 % by conventional flotation to 76 % by carrier flotation. Furthermore, the recovery of ultrafine wolframite was enhanced from 76 % to 97 % by addition of Fe3+ ions during carrier flotation. Similar results were obtained for flotation of a mixture of wolframite (-5μm) and quartz (-10μm). The improved flotation results were explained by the size enlargement of the ultrafine wolframite due to the addition of carriers and stirring at high speed. The collision energy between the coarse and ultrafine particles is much greater than that between ultrafine particles. Therefore, aggregation between coarse and ultrafine particles occurs more easily. The stability of aggregate of particles is also strengthened with the addition of sodium oleate due to the hydrophobic forces between particles. Fe+3 ions decrease the zeta potential of the particles, lower the energy barrier between particles and promote aggregation.

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Ferrous ions enhance copper extraction from chalcopyrite in sulfuric acid solutions in air at ambient temperatures, because they promote chalcopyrite oxidation with dissolved oxygen. However iron-oxidizing bacteria such as Thiobacillus ferrooxidans rapidly consume ferrous ions, suppressing copper extraction. In this paper, three compounds were used to inhibit ferrous oxidation by T. ferrooxidans and their effects on ferrous promoted chalcopyrite leaching were investigated in the presence and absence of the bacteria. Sodium lauryl sulfate and tannic acid suppressed not only the bacterial ferrous oxidation but also the chalcopyrite oxidation with dissolved oxygen, resulting in a suppression of copper extraction. High concentrations of sulfuric acid (> 0.05 mol dm-3) suppressed the bacterial ferrous oxidation and promoted chalcopyrite oxidation with dissolved oxygen, causing enhanced copper extraction.

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Fine particles of monodispersed yttria are desirable for preparing transparent and/or high-performance, -functional ceramics. Various shape of yttria precursors was observed in the precipitates synthesized through homogeneous precipitation from aqueous solution by reacting with each other of thermal decomposition products of urea at 115 °C. Three types precipitates of particle morphologies such as hallow spheres with rough and smooth suefaces, and rodlike shape were synthesized in an aqueous solution containing urea with sulfate ion. All of them crystallized to monophase yttria above 1,100 °C. The calcined particles were hollow basketlike, porous-spherical and rodlike with rough surface. The basketlike hollow spheres were obtained from solution of low [urea]/[yttrium ions] ratio in a short reaction time, and rodlike ones were obtained from solution of high [urea]/[yttrium ions] ratio in a long reaction time. Spherical, rodlike and platelet precipitates were synthesized in an aqueous solution of urea coexisting with nitrate ions, and a monophase of yttria was obtained above 800 °C. These facts indicate that the shape of yttria precursor obtained in the solution coexisting with sulfate or nitrate ions were controlled by the [urea]/[yttrium ions] ratio and reaction time.

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Room temperature leaching of ITO (Indium Tin Oxide) scrap has been carried out to extract mainly indium, using H2SO4 solution of 1N, after mechanochemically treated with Al2O3 powder by means of a planetary mill. The crystallinity of In2O3 in the scrap was changed into amorphous state by the mechanochemical treatment, although In2O3 maintained the crystal structure partially even in the prolonged treatment. The degradation of crystallinity of In2O3 in the scrap resulted in easy extraction of indium at high yield in the leaching process. Al2O3 powder in the scrap plays a significant role to make In2O3 amorphous.

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A newly recycling process for video camera components of AZ 91 D magnesium alloy used for professional market was developed by melting and casting processes in order to satisfy the JIS specifications for recycled AZ 91 D magnesium alloy ingot. Various quantities of Mn were added to the melt in order to avoid contamination by impurities such as Fe, Ni and Cr from paints. Composition analysis and mechanical properties and corrosion resistance of the recycled ingots were also examined. Recovery ratio of the recycled ingots is in the range of 60 % to 75 %. Chemical composition and tensile properties of the recycled ingot with Mn addition of more than 0.23 % is satisfied by JIS specification except for Cu content. Tensile strength and 0.2 % proof stress of the recycled ingots increase with increasing Mn content. The recycled specimens with Mn addition of more than 0.23 % almost exhibit the same level of corrosion resistance as the virgin ingot of AZ 91 D magnesium alloy.

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