Sustainable supply of minerals and energy is global problem. Metals and energy consumption in the Asian countries has increased rapidly with economic growth. The analysis could proceed to examine the role of past trends in GDP and intensity of use in explaining the growth of metals and energy demand in the representative Asian countries, coming presumably to the conclusion that copper demand in Asia could continue at recent rates for at least the next decade or two. Considering the present situation of metals and energy there are anxieties about steep depletions of these resources. Instabilities in the supply and demand of mineral resources in the past were caused by distribution problems or extremely uneven supplies of resources, but the world's mineral productions have now become so large that for the first time in our history, it is questionable whether the world supply of these resources will last well beyond the lifetime. We examine a few depletion patterns such as Hewett and Hubbert diagram from this point of view.

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Based on geological field survey on granitoids distributed in the Chubu Ryoke Belt, orientation and occurrence of macroscopic (outcrop scale) fractures were analyzed to characterize the anisotropic fracture network system in the study area. Variation of P-wave velocity was measured to identify preferred orientation of weak planes developed in the granitic rocks. In northeast part of the Inagawa granite, parallelepiped block structure composed from fractures with three preferred orientation was observed. The structure is inferred to be derived from tensile stress field in the granitic body. On the contrary, in southwest part of the Inagawa granite and the old Ryoke granitic rocks, complex sheared fractures were dominant. Predominant orientations of those macroscopic fractures were close to the directions of major and representative active fault systems of the Chubu Ryoke area such as the Median Tectonic Line (NE -SW strike) and the Atera fault (NW-SE strike).
P-wave velocity measurement revealed that anisotropy of the P-wave velocity was closely related to the distribution of parallelepiped fractures, however, shear fractures had no clear relation to variation of the P-wave velocity.
P-wave velocity measurement has an advantage on prediction of major orientations of parallelepiped joint system developed in granitic rocks, however in the case of highly stressed rock mass, better approximation on preferred orientations of fractures is likely to be achieved with consideration for occurrence of major faults and tectonic stress regime distributed in the area.

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In this study, the behavior of the microscopic failure prior to the macroscopic failure for Tuff is examined. Firstly, uni-axial tension tests were carried out and stress-strain characteristics were investigated. It was found that the anisotropy was small for the strain in the tensile fracture, while the anisotropy was remarkable for the tensile strength.
Secondly, uni-axial compression tests were carried out and various physical properties of the macroscopic failure were examined. It was found that the anisotropy was small for the strain in the compressive failure, while the anisotropy was remarkable for the compressive strength, Young's modulus and Poisson's ratio.
Inelastic strain was defined as a part of circumferential strain. At the point of maximum volumetric strain, it was found that inelastic strain almost equals tensile failure strain obtained by the uni-axial tension test. From these results, it is estimated that microscopic failure is caused by circumferential direction.

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Methane hydrate is one of the potential resources of natural gas in the near future, because it exists in marine sediments or in permafrost regions worldwide. Some extraction methods of methane hydrates from the reservoir has been proposed, such as depressurization, thermal stimulation and inhibitor injection. These are all based on the in-situ dissociation process of methane hydrates that is transformed into methane methane and water. Therefore, it is very important to clarify the physical phenomena of gas-water multiphase flow in porous media and the properties of formation and dissociation of methane hydrates.
We have carried out the experimental study on hot water injection as one of the thermal stimulation methods. From the results, it was found that (1) when temperature in downstream zone of sand column was lower than equilibrium condition, additional hydrate growth was promoted at downstream zone due to migration of cooled water and dissociated gas, (2) as a result, differential pressure increased exponentially, and water permeability of sand column decreased drastically.
For inhibition of hydrate growth and improvement of permeability in hydrate reservoir, we conducted further experimental work on the simultaneous injection process of nitrogen and hot water. Nitrogen has the effect as an inhibitor as well as methanol and salts. In this experiment, firstly, nitrogen was injected into sand column to displace free methane gas, and then hot water injection was started. In the progress of dissociation, temperatures in the sand column and differential pressures, production rate of dissociated gas were measured. Additionally, based on measuring data, water permeability in dissociation process was estimated. Due to the inhibitor effect of nitrogen, it was possible to continue water injection without permeability reduction. Thus dissociated gas production was completed earlier in comparison with normal hot water injection process.

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The rock - fluid interaction on the solid - liquid interface is a complex process comprising diffusion, adsorption, reaction and desorption. According to experimental results of hydrothermal reactions, the leaching layer where specific elements are depleted and secondary minerals are precipitated was formed on the rock surface. The transition of the surface condition plays an important role in the quantitative evaluation of the rock - fluid interaction in natural systems.
The zonal structure of hydrothermal alteration, and leaching and enrichment process in the subsurface region were simulated using the T(thermo)-H(hydro)-C(chemical) coupled mathematical model which is included in the chemical reaction and dynamic function of the solid-liquid interface and overall systems. As an example of zonal structure, the cation exchange of montmorillonite from Ca to Na, and illitization via the illite/montmorillonite mixed layer in a drillhole were analyzed by this model. Particularly, cation exchange reaction is sensitive to the mass transport factor of the solid - liquid interface due to the exchangeable cation in montmorillonite being directly reflected on the in-situ solution chemistry. The transition from Ca- to Na- montmorillonite in the field could be simulated well using the mathematical model under relatively high groundwater velocity and the present geothermal gradient condition. On the other hand, the numerical analysis for illitization did not coincide with the field data under the present geothermal gradient irrespective of dynamic function. This also denotes the capability of cooling of underground temperature.

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Carbon dioxide(CO₂) removal from exhaust combustion gas and biogas is recognized as an important technology to CO₂ reduction. We are developing a new technology of CO₂-removal with a hollow-fiber gas-liquid contactor. In the contactor, the gas flows in the lumen side of hollow fiber, and liquid in the shell side. The gas-liquid interface is formed right outside of hollow fibers because the hollow fibers used are hydrophobic and microporous. The contactor contains a lot of hollow fibers which internal diameters are 320μm, and can produce huge gas-liquid interface area per unit volume. It is so efficient to transfer carbon dioxide between gas and liquid.
To confirm an overall mass transfer coefficient (hereinafter referred to as K), the following experiments on carbon dioxide transfer in the laboratory were made: In the soli-recovery test, an inactive gas swept carbon dioxide from carbonated water. In the soli-supply test, a mixed gas contained carbon dioxide contact with static water excluding carbon dioxide, and with agitated water. In the supply-recovery test, a mixed gas contained carbon dioxide contact with static water and an inactive gas swept carbon dioxide from the carbonated water concurrently.
In each test, the water was sampled from the contactor, and the concentrations of dissolved carbon dioxide were measured with a gas chromatography. Using mathematical model of the test equipment, the value of K was calculated. These results showed that K depends on ‘water temperature’ and ‘water flow’ without relation to a flux direction and the distance between hollow-fibers, and the water flow system was more effective. Comparing with another technology(packed tower), it was proved that the new one had large dominant CO₂-removal forces.

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To obtain highly ionic conductor of sulfides, a solid solution of 95CaS-5Na₂S was prepared by sintering the high-purity powder mixture of CaS and Na₂S under the pressure of 3kg/cm² and the temperature of 1423K. The electrical conductivities
of the solid solution were measured under a sulfur partial pressure range from 10^-10 to 10³ Pa, furthermore the concentration cell Fe, FeS|95CaS-5Na₂S|Mn,MnS was constructed and the electro motive force measurements were made.
The conductivity increased by more than two orders of magnitude rather than that of CaS, and was independent on the sulfur partial pressure under an atmosphere of P_S2=10^-10-10³ Pa and a temperature range of 973∼1173K. These results lead to the conclusion that the 95CaS-5Na₂S solid solution is an ionic conductor.
Because the measured emf values for the concentration cell agreed well with the theoretical values calculated from the Nernst equation, it is concluded that the ionic transference number of the solid solution is unity.

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