The annual 70 million tons' CO₂ injection separated from flue gas of fossil fueled power plants into aquifer may reduce Japan's artificial carbon dioxide emission as much as 6% with annual cost of 420 billion yens that match 1, 200 yens/c carbon tax. Geological sequestration of CO₂ is a technically and economically feasible option for mitigation of greenhouse gas emission.
Carbon dioxide injection under gas-hydrate-filled layers or under permafrost layers can realize the greenhouse gas mitigation and recovery of unused natural gas. Autogenous sealing of CO₂ in deep and cool aquifers assures virtually complete and practically unlimited subsurface containment of CO₂.
Chemoautotrophs fix carbon dioxide in deep aquifers even without sun light. Methanogens can convert CO₂ into methane in deep anoxic aquifers. Biogenetic restoration of subsurface hydrocarbon deposits is expected in CO₂injected aquifers after tens or hundreds of years. Microbiological recycling of CO₂ in aquifers is an attractive future technology for energy-short countries such as Japan. Important key for underground CO₂ recycling is hydrogen supplies owing to microbial decomposition of organic matter and from geochemical water-rock interaction in deep rock formations.

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The injection of CO₂ below the seafloor offers several advantages for seques tration, particularly that it may retard the return of CO₂ to the atmosphere for long periods of time and minimize any environmental impact on the benthic ecosystem. A number of marine geological environments contain natural aqui fers with impermeable seals that are potentially suited for CO₂ injection. Owing to 30 years of scientific drilling in the deep ocean, much is already known about such environments. Two possible locations which have been previously drilled and studied are compared in this paper-one in natural hydrate-bearing sediments and one in oceanic basalt crust. Although additional measurements and reservoir models are needed for a comprehensive and more conclusive evaluation, the existing information suggests that an oceanic crustal site is more likely to accommodate a substantial volume of injected CO₂. Long-term monitoring of such sites would also help to establish a quantitative understanding of the fate of CO₂ sequestered below the seafloor.

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The study of hydrates of carbon dioxide and its mixtures is gaining importance due to its environmental implications. The sequestering and disposal of carbon dioxide in the form of its hydrates is one of the concepts under serious consideration. In that regard, the knowledge of the conditions at which hydrates of carbon dioxide and its mixtures form is necessary. In this paper, incipient equilibrium hydrate formation conditions for three binary mixtures of nitrogen and carbon dioxide, in the presence of pure water, are presented.

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Incipient equilibrium hydrate formation pressures for the methane-carbon dioxide-neohexane-sodium chloride-water system were measured between 274.1 and 276.2K. In addition, similar data were obtained for the methane-polypropylene glycol-sodium chloride-water system at temperatures ranging from 274.2 to 282.7K. The isothermal pressure search method was employed to locate the minimum pressure at a constant temperature. The concentration of methane on a water-free basis was 50% in the methane-carbon dioxide gas mixture.

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The possibility of CO₂ liquid disposal into an aquifer beneath close to the sea-floor was studied using a simple calculation flow model. This study focused on the possibility of CO₂ disposal in liquid phase below the critical temperature, because CO₂ density can be larger in the low-pressure range than that over the critical temperature.
Based on the equilibrium lines in the pressure and temperature map, an aquifer located at about 200 m under the sea-floor with sea depth around 500 m is capable of serving as a targeted zone to carry out CO₂ liquid disposal. That means that the sea level of the aquifer is around -700m from the sea surface (absolute pressure is approximately 7.3MPa), and it is expected that the sea floor temperature is in the range of 4-6°C and the aquifer temperature is 15-20°C. For this case, it can be assumed not only that the CO₂ goes in solution form with the aquifer water but also that the CO₂ liquid flows with replacing the water. This shows that a greater CO₂ quantity can be injected compared with that of the supercritical condition. Furthermore, the sediment between the sea-floor and the aquifer functions as an impermeable sealing cap for CO₂ leakage to the sea by forming CO₂ hydrates with water or sea water. Even if the cap is not formed, since the conditions at the sea-floor satisfy the CO₂ liquid condition, there will be no large environmental impact. This study provided a design scheme to decide transmissivity of aquifer, CO₂ injection rate, inner diameter of injection tubing and number of wells for CO₂ disposal system into the aquifer below the sea-floor in liquid phase below the critical temperature.

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CO₂ underground storage might be one effective system to mitigate global warming induced by the increase of greenhouse gas emissions. Since the aquifers in Japan have enough capacity to store CO₂ captured at several new and powerful coal-fired power plants, they could be good reservoirs to sore CO₂. In taking CO₂ storage in aquifers into consideration, it is important to inves tigate the CO₂ behavior injected into aquifers for the effective and safe CO₂ storage.
This paper describes the CO₂ behavior injected in aquifers simulated by one of numerical simulators commonly used for oil and natural gas field development in the world. Simulation studies were performed for the injection of CO₂ into an aquifer under supercritical state conditions. Pressure rise in an aquifer and the generation of free-CO₂ gas zone were investigated.

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Alberta's economic engine is fueled mainly by the fossil fuels industry. Energy generation from coal and the production and burning of oil and natural gas are the main sources of carbon dioxide (CO₂) emissions in Alberta, Canada. Over the next decade, the multi-billion dollar expansion of oil sands production, population growth and the demand for energy will present a major challenge to Alberta, amidst the current world initiatives on global warming. In this study, the authors present detailed design, economic and risk models and anal ysis of CO₂ disposal under aquifers and develop appropriate strategies for sound economic policies in dealing with CO₂ emissions in Alberta. The design and construction of the aquifer disposal system is based on CO₂ capture from flue gas using the KS technology, CO₂ liquefaction, transportation and injection. Projected CO₂ emission levels are modeled using econometric theory based on the derived energy demand and prices, population and industrial growth and technological changes for the period between 1999 and 2012. Detailed economic models of the aquifer disposal system are used to predict the long-term minimized cost curves that ensure atmospheric balance under given projected CO₂ levels. Quantitative risk analysis using variance simulation and the Latin Hypercube techniques are used to predict the long-term risks associated with this disposal option. The results show that the expected capital investments over the 14-year period is 3.65 billion and the annual operating cost is 112million. The energy cost is expected to increase by 24% from 0.043 to 0.053/kWh. The expected unit cost associated with the aquifer CO₂ disposal is about 30/ton of CO₂ in the first four years of operation. This unit cost gradually decreases as a result of economies of scale from 36/ton in year one to about $18/ton in year four. Risk simulation also shows that the unit disposal and energy cost will be stable in this period (about 2% COV) as a result of the stable economies of Alberta and Canada.

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The modeling of swelling behavior is a necessary step to evaluate swelling minerals as sealing materials and to design an underground waste repository. The purpose of this study is to construct a mathematical model to describe the swelling behaviors of clay minerals and to develop a new FEM program in which a hydromechanically coupled procedure is incorporated to analyze stresses, displacements, uptakes, and volume expansions/pressure build-ups in swelling geological materials.

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It has been proposed that the disposal of the greenhouse gas, namely, carbon dioxide into deep ocean could be a solution to control the concentration of the same in the atmosphere. Analysis of the proposed schemes demands data on the physical properties such as, structure, hydration number, density and mechanic al property and the formation and dissolution characteristics of CO₂ hydrates. In this paper, we review the laboratory investigations and in-situ observations on CO₂ hydrates, discuss possible scenarios that need to be given due consideration in the case of deep sea disposal, merits of sub-seabed disposal and the present status and future of CO₂ disposal.

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We studied the involvement of γ-aminobutyric acid (GABA) as a neurotransmitter in the inhibition of the cat's superior colliculus (SC) that is one of the important visual center. Iontophoretical applications of GABA and the antagonist bicuculline were preformed to the SC neurons in anesthetized cat and the effects on the neuron activities were examined. Besides the distribution, of the neurons which have GABA receptors was investigated immunocytochemi cally using an antiserum raised againist bovine serum albumin-conjugated GABA. The results suggested that GABA at least involved in the inhibition mediated through GABA_A, receptors.

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The spectra of magneto-optics and of absorption coefficient of UO₂ caused by the intra-atomic 5f-6d dipole transitions are calculated assuming the electro static, the spin-orbit interactions and the cubic crystalline field, and the results fitted to the experiments are obtained. Then, the atomic Slater-Condon parameters and the spin-orbit coupling constants of U⁴⁺ interpolated from those of Th²⁺ combined with the atomic structure calculation are used, and the exchange integrals G_k (k=1, 3, 5) and the crystalline field parameter for 6d electron in 5f6d configuration are taken as abjustable ones. It is shown that the best values of them are A₄<r⁴>=1600cm^-1 and 1.3G_k, where G_k are the values evaluated from the atomic structure calculation. It is clarified that the crystalline field plays an important role since the energy separation between two main peaks is nearly equal to splitting due to it.

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The stirred mill is regarded as one of the most efficient devices for micronizing materials and has come to be actively used for preparation of fine particles. Recently, the demand for ultrafine particles is increasing in many kinds of industries.
In this paper, an autogenous grinding to get submicron or micronized particles based on frictional action of feed material has been carried out using a stirred mill. The mill used was made of stainless steel and its volume wasabout 5.5 liters and has 12 impellers. Samples used were silica glass and limestone. The feed mass was 5kg and the feed size was 20-13mm. In the present work, a operating parameter was stirring speed. The ground products were sieved in the size range from feed size to 325mesh (45μm), and from 45 to 0.17μm, the size distributions were measured by a laser diffraction and scattering method. The progress of grinding was evaluated by the increasing rate of fine particles. The effect of properties of samples on the grinding rate was studied.
As a result, It was found that an autogenous grinding with a stirred mill was more effective method for producing fine particles of limestone which is not elastic solid than silica glass which is nearly perfect elastic solid.

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Ultra fine magnetite particles, with the mean particle size of 75Å, were produced at pH 12 after adjusting the mole ratio of Fe²⁺/Fe³⁺ to 0.5 by partial oxidation of the waste pickling liquor of steel. After double adsorption of oleic acid ion and dodecyl benzene sulfonate (D. B. S) ion on the surface of magnetite particles, magnetite hydrophilic magnetic fluid was produced by dispersing the magnetite particles in ethylene glycol solution. The ethylene glycol based magnetic fluid enhanced the capability of oil seals. The life span of the sealing apparatus composed of mild steel components was remarkably extended due to the high corrosion resistance of ethylene glycol.

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The present paper primarily concerns itself with the use of aluminum alloys for marine applications. The objective of this research is to consider the effects of Mg concentration, slurry speed, sand grain size, sand-to-water ratio and temperature on the sand erosion resistance of five typical types of aluminum alloys. Quantitative relationships for these were also derived.
Cylindrically-shaped test specimens were attached to a rotating disc immersed in a slurry. Erosion rate was based on the amount of weight loss. Mg concentration varied depending on the alloy used. Slurry speed varied with the rotation of the disc. Three types of sand were examined and their respective grain sizes determined. Sand-to-water ratio was varied from 0-40% and tests were conducted using temperatures of 293K and 280K.
From the given conditions, the following conclusions were derived. In Al-Mg type of alloys, the sand erosion resistance increases when the magnesium content increases. The factors affecting erosion rate (W_k) mainly consist of slurry speed (V), sand grain size (F) and sand volume percentage (p). Also, the relationship may be shown in the following formula:
W_k=K·p^1/2(Vⁿ/F^m)

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Terphenyl-modified, β- and γ-cyclodextrin analogues (1 and 2) have been prepared to investigate their fluorescent molecular sensor ability for organic guests, such as terpenoids or bile acids. These hosts show a pure monomer fluorescence with increasing or decreasing by accommodation of a guest. The extent of fluorescence variation with a guest is used to display the sensing ability of those host molecules. Host 1 detects smaller guests such as terpenoids with much higher sensitivity in a 10vol.-% dimethylsulfoxide (DMSO) aqueous solution than those of in a 20vol.-% DMSO aqueous solution. On the other hand, larger guests such as bile acids were detected with less sensitivity in a 20vol.-% DMSO aqueous solution by 1. The sensing ability of 2 for a guest examined was hardly effected by the solvent. The molecular sensing system combined with 1 and 2 could be useful method, because their binding behaviors for guests are different, in which the parameter values indicating the sensing ability obtained from 1 were almost positive, whereas the parame ter ones for 2 were negative.

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An effective numerical algorithm is developed to simulate extension of the interlaminar delamination in a laminated composite based on the three dimension al finite element method. As use of the conjugate gradient or ICCG method to solve a system of linear equations minimizes occupation of memory space in computation, matrix of linear equations is made to be symmetric for contact problems on the delaminated interface of the composite. The extension of the interlaminar delamination is simulated in a cross-ply laminated composite with four layers under concentrated load on the center of the composite. Distribution of deflection on the laminated composite with the delamination is also shown graphically.

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Si₃N₄ fine particles were coated with AN by chemical vapor deposition reaction and then sintered under uniaxial pressure in a hot-press. The effect of coating quantity on the mechanical and thermal properties of composite compact was measured and the data were compared with those for Si₃N₄ itself. As a result, the flexural strength and heat conductivity of the composite samples went through maximum and the Vickers hardness slightly increased with the amount of AlN deposit. It was shown to be possible to obtain composite compacts with mechanical properties exceeding the corresponding properties of sam ples made of uncoated Si₃N₄ particles. The heat conductivity of composite sam ples did not change considerably in comparison with uncoated ones due to low amount of A1N deposit and its non-uniform distribution at high reaction temperature.

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Simultaneous synthesis and densification of α-Zr (N) (hexagonal) from zirconium powder compacts are achieved by self-propagating combustion under high nitrogen pressures. Nitrogen contents increase from 12.2 to 23.5 at% with decreasing compacting pressure and increasing nitrogen pressure. The material with the highest density (99% of theoretical) exhibits a Vickers hard ness (H_v) of -6.2 GPa and a bending strength (σ_b) of -205 MPa. Electrical resistivity (ρ) is determined to be -2.0×10^-6 Ω·m at room temperature.

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The preparation of fine powders by grinding may be accomplished by either a dry or a wet process and the differences between these have been discussed. In general, it is well known that there are many mechanical properties which have direct effects upon the grindabilities of solids. Breaking properties, espe cially, are related to the grindabilities. A practical grinding process involves every breaking condition and these are complex and cannot be measured directly. In addition, the difference in breaking strength in different atmospheres is also known. In this review, bending tests were carried out on glass material in order to investigate the difference between dry and wet grinding. The quantitative effects of water on bending strength and crack propagation on glass surface were studied fundamentally. As a result, it was found that the wet strength is less than the dry, the crack length in water is larger than that in air and a wet grinding process is useful from the point of view of strength of solids.

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