There are many measurement methods of crack characteristics, and some of them have received practical application. Many of them are using P-wave velocity to measure the crack characteristics. The measurements of P-wave velocity are influenced by the frequency of P-wave. In order to measure P-wave velocity with high accuracy, high frequency P-wave is needed. However, the higher P-wave velocity is, the larger the absorption of transmitted wave is. In many cases of in-situ measurements by using high frequency P-wave, the accuracy of measurements become low, for the reason that the effective transmitted distance is short and S/N ratio is low. In the present paper, the measurement method of crack tip position which is free from frequency of P-wave is proposed. This method uses the diffracted P-wave from the tip of a crack. The polarity of first motion of diffracted P-wave from the tip of a crack is dependent on the angle of incidence , the angle of diffraction and Poisson ratio of media. The measurement of the angle of incidence and the angle of diffraction where the polarity is changed is free from the frequency of P-wave. Therefore this methods is not influenced from the frequency of P-wave, and the suitable frequency by the condition of in-situ measurement can be selected. In the persent paper, the applicability of proposed theory about the change of the polarity of first motion of diffracted P-wave from the tip of a crack to in-situ measurement is studied. As the result of theoretical study and experimental study using Inada granite, it was clarified that the measurement using the proposed theory was effective to the measurement of crack tip position.

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Previously, the authors have developed a Three-dimensional numerical code by direct boundary element method for non-steady heat conduction. In order to confirm validity of the calculation system, at that time, they carried out both numerical calculation and analytical calculation for the model of infinite medium around a spherical cavity and compared numerical solution with strict solution. It was found from the comparison that precise solution can be given by using their numerical code. However, in the practical problems, thin fracture must be modeled in case as that artificial fracture produced by hydraulic fracturing is taken in. In addition to that, the detail of the procedure to calculate the influence coefficients related with the elements which consist of the fracture boundary should be explained. Therefore, in this paper, the authors describe the concrete procedure on calculation of the influence coefficients first and they carried out numerical calculations in which fracture boundary is taken next. As the numerical model, however, they dealt with non-steady heat conduction in infinite medium around a penny-shaped fracture in order to simplify the problem and to make explanation of the calculated result easier, because no strict solution can be given for any problem including fracture boundary. Furthermore, the time integral method was used as the calculation method and linear distributions of initial rock temperature was assumed in modeling. In such modeling, no volumetric integration is needed if the time integral method is adopted and, one can deals with the model where initial temperature distribution varies linearly as same as the model where it is constant.

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In order to measure concentration of some kinds of gases flowing or emitting abruptly in underground space such as roadway in mine and tunnels, we have been studying a continuous and real time measurement system for gas concentration by means of a photoacoustic effect. In the previous papers, a calibration system and procedure to obtain the characteristics of photoacoustic signals, which was the relationships between gas concentration and photoacoustic intensity when CO2 laser was used, were examined. In this paper, we describe development procss and expermental results of new measurement system for atmospheric gas concentration changing with time. On the development process, the cooling system for laser discharge tube was converted from water circulation type to air circulation or electronic element cooling type to achieve the portability. Also, the doubletube type photoacoustic cell was improved to draw air in it for the continuous measurement of photoacoustic signals. Using the new systems, laboratory experiments were carried out to obtain the characteristics of the photoacoustic signals, and to compare the measurement accuracy of this system to the previous system. Consequently, we confirmed the availability of this new system in time response and in quantitative monitoring by the continuous measurement of CO2 gas in the atmosphere.

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In fine grinding practice the efficiency of comminution depends largely on the behavior of freshly formed fine particles. In the case of a dry tower mill, fine particles are directly removed due to circulating air flow generated inside the mill, and immediately particles are classified in the classifying column. Especially in the Tower Mill KD - 3, in order to achieve a high classifying efficiency it is essential to reduce the air turbulence in the classifying column. Although it had been provided with the series of nets in the column of the KD - 3, the efficiency of nets was not clarified. In this study, by investigating the roles of nets, it was found that the air turbulence reduced and the classifying efficiency was improved by setting with the nets in the column. The results of these investigations using 4 type columns (CLA 0, CLA 1, CLA 2 and CLA 3) can be summarized as follows: (1) The weights of products in the cyclone increase using the no-nets classifying column (CLA 0), conversely the weights of products in the classifying column decrease. (2) The series of nets in the classifying column have no influence on the electric consumption of the blower motor and stirring motor. (3) The relationship between maximum and 50 % particle diameters was proportionally and by using the columns provided with nets (CLA 1, CLA 2 and CLA 3), the overflow products and underflow products were classified by the high classifying efficiency. (4) The maximum particle diameters of products were indicated by the corrected curve which is estimated by the assumption of Stoke's law. (5) The air flow rate of duct and the pressure drops of the column were approximately quadratic curve. And the maximum particle diameters of products in the cyclone were proportional to the pressure drops of the classifying column.

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Based on estimated distribution ratios of several impurity elements between Na2CO3 slag and molten copper, a mathematical model has been developed to discuss the application of Na2CO3 flux to the removal of impurities from molten copper, in terms of the Na2CO3 flux consumption. The effectiveness of the Na2CO3 flux treatment to reduce the impurity contents in molten copper to 0.1 mass ppm, the level required for the high purity copper, is discussed by the model and confirmed by equilibrium distribution experiments.

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Thermodynamic properties of aluminum in molten silicon were measured by equilibrating silicon melts with mullite(s)-Al2O3(s), mullite(s)-SiO2(s), and SiO2(s) at 1,723 K and 1,773 K.Based on the results, (ａ) the standard free energy change for the oxygen dissolution into molten silicon, (ｂ) the activity coefficient of aluminum at infinite dilution referred to pure liquid, and (ｃ) the interaction parameters related to aluminum in molten silicon were determined to be：(ａ) 1/2 O2(g) = (mass%, H, in Si melt):Δ(ｂ) = -1.8(±0.1) (at 1,723 K), = -1.21(±0.01) (at 1,773 K)(ｃ) = 260(±10) (at 1,723 K), = 41(±1) (at 1,773 K eOAl = -0.63(±0.08) (at 1,723 K), eOAl = -0.57(±0.01) (at 1,773 K), respectively, for 1,723 K∼1,773 K.Finally, the stability diagram of the Si-Al-O system was established.

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The layered phosphates, mainly represented as MIV(HPO4)2·nH2O (M：metal ion), are the compounds which have the layered crystal structures. The layered phosphates have a lot of advantages such as high selectivity, and high stability against the strong acid solutions, radioactive rays and temperature owing to their steric structure as inorganic ion exchangers. Lately, the layered phosphates are remarked increasingly as a host material for intercalation compounds. If the quaternary ammonium ions can be intercalated into the layered phosphates, the disadvantages of heat resistance for organic medicaments might be improved and antibacterial properties might be provided to the phosphates. Zr(HPO4)2·H2O and AlH2P3O10·2H2O were selected for the present investigation as hosts of intercalation of the quaternary ammonium ions. It is clarified that benzalkonium ion intercalates easily in Zr(HPO4)2·H2O by the reaction between benzalkonium chloride solution and Zr(HPO4)2·H2O, and almost pure intercalation compounds can be obtained at the concentration of the benzalkonium chloride less than 5.7 mmol dm-3. On the contrary, butyl amine treatment is necessary for the intercalation of the quaternary ammonium ions to AlH2P3O10·2H2O. The intercalation compounds obtained here show the sterilizing effect for several bacteria and improvement of the thermal stability of quaternary ammonium ions by holding in Zr(HPO4)2 and AlH2P3O10·2H2O.

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TiO2 -coated hollow volcanic glass spheres (Shirasu-balloons) were developed by a thermal decomposition method of hydrolytic polymers from tetra-n-butoxy titanium, and their properties were investigated. Hollow volcanic glass spheres of above 100 μm were coated with titania hydrate formed by a moistening process by steam Ti (OCH2 CH2 CH2 CH3 )4 during heating at 95 °C for 40 minutes. After drying at 120 °C in air for 12 hours, these coated spheres were performed by heat treatment for 2 hours in air at temperature ranges of 400 ∼ 1,100 °C for the purpose of controlling of crystal structure from anatase to rutile.The tetra-n-butoxy titanium could be transformed very easily into titania hydrate by using the moistening process using steam. The crystal structure formed in temperature range from 400 to 800 °C was anatase. With increasing the temperature of above 800 °C, the anatase structure was transformed into rutile and then completed only rutile at 1,100 °C. SEM analysis of the surface before and after heat treatment revealed homogeneous coating layers with TiO2 .

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The production method for uniform droplets has been investigated usingultrasonic-wave. The ultrasonic-wave was loaded to the fluid, which was fed by a double plunger pump and was spouted out from the nozzle. This studywas attempted that the uniform droplets are prepared by controlling theflow velocity and the diameter of nozzle. The diameter of the nozzles was 30 ∼ 100 μm and the frequency of the ultrasonic-wave was adopted to be 33.55 kHz. The synchronized flash was applied in order to take photograph in which the uniform particle could be observed. The accumulated particles were taken some conditions. It was suggested that this method was useful to prepare uniform particles in the industrial field. The flow velocity was found to be one of the important factors to regulate the particle diameter. The distance between particles did not depend on the flow velocity without ultrasonic loading but it linearly depended on the flow velocity with ultrasonic loading. This "ultrasonic" method is believed to be one of the most promising routes to obtain the perfectly uniform particle.

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