Acoustic Emission method (AE method), which utilizes the Kaiser effect in rock, is one of simple methods for measuring in- situ stresses at great depth. However, it has not been recognized as a reliable method for lack of the fundamental studies about the Kaiser effect of rocks. In this study, to support the method, two basic studies were carried out. In the first study, the effects of both stress level and elapsed time after unloading on the Kaiser effect were investigated for a granite in uniaxial compression. The Kaiser effect was observed clearly below the onset of dilatancy. However, AE activity in a pre-stressed specimen tended to recover with elapsed time. In the second study, model tests were carried out to investigate the mechanism of the Kaiser effect at low stress by using a glass plate containing an inclined crack. Both the Kaiser effect and the recovery of AE activity with elapsed time were observed in association with sliding of the closed crack surfaces. The crack which had slid by loading did not slide back completely during unloading, and shear displacement remained along the crack after a preloading cycle. The Kaiser effect occurred due to the residual shear displacement. Recovery of AE activity with time coincided with time-dependent recovery of the residual shear displacement.

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In order to analyze the lateral vibration of an offshore structure supported by the seabed layer, the effect of this layer on the vibration must be taken into consideration. In this study, firstly, the static stiffness of the seabed sand-layer was determined by equating the theoretical and experimental results on the force-deflection relationship at the top of an elastic pipe, which was partially supported by the sand layer. Then, the natural frequency of lateral vibration of the pipe was theoretically obtained by using the above-obtained static stiffness of the sand layer. Furthermore, experiments were carried out on the free lateral vibration of the pipe and the experimental natural frequency of the lateral vibration was obtained. Finally, the theoretical and experimental natural frequencies were compared to examine the validity and applicability of the evaluation method developed for the static stiffness of sand layer, and to observe the difference between its static and dynamic stiffness.
The results obtained are as follows (1) The natural frequency of the pipe supported by sand layer is smaller by about 30-98% than that of the pipe fixed rigidly by the layer. Therefore, it is essential to consider the stiffness of the layer in the analysis of lateral vibration of an offshore structure.
(2) The theoretical natural frequency calculated by using the static stiffness of sand layer obtained in this study is lower by about 10-22% than the experimental frequency, indicating that the dynamic stiffness of sand layer may be greater than the static one.
(3) The method developed in this study for evaluating the static stiffness is easier and more useful than the existing method for practical application though about 20% error is involved in the analysis of the natural frequency.

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A preparation test of activated carbon from bark wastes in wood industry was carried out for utilization of them. This test consisted of carbonization and activation with alkali chloride, alkali hydroxide and alkali carbonate. Carbonization test was performed in a muffle furnace and an inner heat type fluidized bed furnace. Carbonization treatment was necessary to produce the activated carbon of high adsorptive capacity.
Adsorption capacities of the products activated with alkali hydroxide were higher than those by activation with alkali chloride or carbonate. The internal surface area was over 2, 000m²/g, methylene blue adsorption was over 1, 000mg/g and benzene gas adsorption was over 150 (w/w)%. The capacity was 2-4 times larger than that of commercial activated carbons. Pore size distribution test showed that the activated carbon has more numbers of pore numbers under 2nm in size than that activated with steam, zinc chloride and phosphoric acid.

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Kyushu Metal Industry Co. Ltd.(Kitakyusyu, Japan) has developed and turned over for exploitation of a shredder plant for recovery of iron, aluminium and copper from automobile scrap. The recovery system involves a Lindemann Shredder (2000Hp) at the head of the process and two magnetic separators for recovery of iron. The recovery of non-ferrous metals from the non magnetic products includes the steps of classifying into an Air Jet Separator, hand sorting of massive non-ferrous metals and rubber materials from the heavy fraction and trommel screening of the other materials into three fractions: +50, -50+10 and-10mm. The +50mm size fraction is hand sorted while the-50+10mm size fraction is separated using a new system which involves the ECHO Metal Jig-type LP, the ECHO Heavy Mdium Separation system and the Eriez Eddy Current Separator. Concentration of the-10mm size fraction is facilitated due to the ECHO Metal Jig-type SP.

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Six kinds of coal were used to investigate composition of minerals in the coals and their removal by gravity separation. The minimum ash content attainable by gravity separation was determined from the results of float-sink test and it was unique for each coal sample. The main species of mineral matter were identified by X-ray diffraction of low temperature ash. The amounts of oxides in high temperature ash were determined with inductively coupled plasma automatic emission spectroscopy and converted into the amount of minerals based on the knowledge of mineral decomposition at high temperature. Quartz and kaolinite were major minerals in most of the coals and rejected easily by gravity separation. Mineral matter difficult to reject by gravity separation was defined in terms of mineral composition and their behavior with gravity separation. The ash content resulting from the mineral matter difficult to reject was closely related to the minimum ash content, which could be estimated from the total amount of bassanite, calcite, MgO, Na₂O, K₂O, P₂O₅ and TiO₂in feed coal, too.

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Mineral matters in six coal samples from different localities were classified into four groups; A) mainly quartz, B) pyrite, C) mainly clay minerals and D) iron oxide. The size distribution and liberation degree of each group mineral were measured using an image analyzer equipped with a microscope. Minerals of A, B and D groups were easily liberated from coal by grinding. On the other hand, C group minerals were easily crushed but often remained and attached to the coal particles. Based on the results measured and observed, a liberation model was proposed to evaluate the liberation behaviour of the minerals. Using the model, liberation degrees were calculated and the values agreed well with the measured values.

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Release analysis (RA) and oil agglomeration (OA) procedures were investigated to determine a standard testing method for de-ashing of fine (>10μm) and ultra-fine (<10μm) coal. The results indicated that OA was suitable for both fine and ultra-fine coal, but RA only for fine coal. Oil agglomeration tests were carried out for Datong, Wandoan and Illinois coals of different sizes. Based on the liberation model previously proposed by the authors and the removal characteristics of mineral matter by the oil agglomeration, a new simulation method was developed to predict the amount of minerals and ash content of clean coal. There was good agreement between experimental and calculated results for the clean coal of agglomerates.

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This paper describes the use of an artificial neural network for the data analysis of the plasma synthesis of acetylene from coal and other hydrocarbons using 100kW plasma reactor. The experimental data have wide variety of experimental conditions such as electric power input, raw material species and their feed rate, quenching conditions, and so on. 89 experimental data sets were stored in a 4-layered neural network having 37 input units and 6 output units within the maximum error of 7.4%. The results were compared with those of linear regression. Although the extrapolation was not always satisfactory, the interpolated data estimated by the trained neural network were found to be excellent. It is expected that neural network technique can be a useful and versatile tool for the data analysis as well as statistical techniques.

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As a basic study for the application of the reduction-diffusion (R-D) process to the production of Sm₂Co₁₇ type magnet materials, reduction reactions of Sm₂O₃ and ZrO₂ by matallic Ca, and the effects of requisite elements for the materials on the reactions were investigated by the differential thermal analysis. When Sm₂O₃ or ZrO₂ alone was reduced, the reduction reaction began immediately after the fusion of Ca as has been reported for the case of the reduction of Nd₂O₃ by metallic Ca. When they were reduced in the presence of the requisite elements, however, Cu has a distinct effect to lower the reduction rate of Sm₂O₃, the reason of which has been attributed to the gradual formation of a Cu-Ca melt necessary to cause the reduction and also to the decrease in Ca activity due to the melt formation.
A Sm₂O₃ block prepared by arc-melting Sm₂O₃ powder was reduced by Ca vapor to study the effect of CaO formed on the block during the reduction reaction. It has been found that the CaO layers formed on the Sm₂O₃ block were porous and did not obstruct the passage of Ca vapor. The formation mechanism of the porous CaO layers has been discussed and compared with the formation mechanism of dense CaO which plugs pores in a porous rare earth oxide pellet. Further, it has been concluded that, in the actual R-D process, the reduction reactions of rare earth oxides may not be hindered by the formed CaO.

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Using two kinds of fly ash samples, production test of the slow-release type potassium silicate fertilizer at 800-950° for 10-40 minutes in air with potassium carbonate, calcium hydroxide and magnesium carbonate was conducted. From the experiment we obtained following results:
1) The solubility of SiO₂ in 0.5 mol·dm^-3 HCl solution ranges from 53 to 92% and the solubility of K₂O in 2% citric acid ranges from 60 to 75% depending on the calcination condition.
2) By heat treatment at 950°for 20minute, the silicate compounds clearly changed to K₂Al₂Si₂O₈ (or K₂ (Al, Fe) ₂Si₂O₈), K₂MgSiO₄ and α'-Ca₂SiO₄. These compounds are soluble in 0.5 mol·dm^-3HCl and 2% citric acid.
3) The addition of a suitable amount of K₂CO₃ and MgCO₃ was favorable for the increase of the solubility of Si0₂ in 0.5 mol·dm_-3 HCL solution and the solubility of K₂O in 2% citric acid.

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In recent years roadheader has been a predominant method of tunnel drivage in Japanease coal mines. Since the success of roadheader is more sensitive, its application should be made after proper evaluation of geological condition and rock characteristics in order to predict the machine performance and bit consumption and so on. Prediction of the performance of roadheader has in the past been based upon unconfined compressive strength. However, this prediction is not good because the fragmentation mechanism is not considered well. It is more important to consider the consumed energy value than the unconfined compressive strength for criterion or prediction of machine performance.
From these points of view, this paper discusses the specific energy in terms of surface area obtained by the impact hardness test in order to estimate the performance of heading machines. Predicting equation having good correlations with the performance of roadheader drivage has been developed by using the RIHN (Rock Impact Hardness Number) and the rock mass property, RQD (Rock Quality Designation).

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This paper is concerned with the stereo vision system with using laser spots and image processing. The most significant problem in the stereo vision system is to determine the correspoinding points in different images. As it is very difficult to determine the corresponding points uniquely, laser spots were used in this study to make the constrained corresponding points, and images were divided into some sections. The previous correlative method was applied in each section to reconstruct the shape of the object. It was confirmed that this method can reduce the mismatching points and the processing time.

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The effects of alcohol and surfactant on hydration forces with aqueous oxide suspensions were investigated. It was found that the primary hydration force with silica decreased with the increasing amount of ethanol in the suspension, while the secondary hydration force with rutile increased with the same condition. The surface dehydration of silica caused by ethanol may be reponsible for the decrase in the primary hydration force. For the case of rutile, the increase in the secondary hydration force may be attributed to the increased adsorption of hydrated Na⁺ as observed at oxide/water interfaces in mixed solvent systems reported elsewhere
Dodecylamine-hydrochloride (DAH) was added to the rutile suspension and its effect was investigated. The result suggested that there was a hydrophobic attraction, the magnitude of which was much larger than the hydration forces. At relatively high DAH concentration and at alkaline pH, an additional repulsion not considered in the classical DLVO theory was observed with rutile. The magnitude of the repulsion was comparable to the secondary hydration force observed with rutile at high NaCl concentrations.

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