The Earth is the miraculous body, where its planetary conditions fit the conditions for life and the Sun's mercy gives rise to the prosperity of life. The eat-eaten connection of life is known as food chain, and almost all of the food chains on Earth start from photosynthesis, and photosynthesis depends in turn on the radiation from the Sun. In this sense, most of the Earth's organisms are Sun-eaters ultimately. However, recent studies proposed the significance of the lives independent of photosynthesis such as the ones in deep-sea and deep subsurface. Findings of the life in the dark facilitate the recognition of Earth-eaters, and the idea that deep subsurface of the Earth (and possibly other planetary bodies) serves as the cradle and nursery for life.
The idea of deep subsurface life is not necessarily new, however, it is since 1980's that the idea has been scientifically hypothesized and tested. By now, the existence of deep subsurface biosphere is scientifically recognized, and current interests are placed on: the abundance (biomass), diversity, biological limit (potentials), involvement in biogeochemical cyclings, and association with the origin(s) of life. Even astrobiological curiosity relates the ubiquity of "life in the dark" in deep subsurface to the presumed presence of extraterrestial life. This communication provides the geo-biological background of the deep subsurface biosphere and reviews some important topics from recent studies.

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Factors that determine the suitability of limestone for industrial use are contents of calcium oxide (CaO) and impurities. From 244 sample points in 18 drillhole sites in a limestone mine, the content data of four impurities, SiO₂, Fe₂O₃, MnO, and P₂O₅ were collected. Since the spatial correlations of content data are not clearly shown by variogram analysis, a feedforward neural network was applied to estimate the content distributions. The network structure consists of three layers: input, middle, and output. Input data to the network are coordinates of a sample point, lithology such as conglomeratic limestone, and kind of fossil. Output data from the network are the contents of SiO₂, Fe₂O₃, MnO, and P₂O₅. Numbers of neurons in the middle layer and training data vary with each estimation point to avoid overfitting of the network. Several important characteristics of the three-dimensional content distributions were detected through the network such as the continuity of low content zones of SiO₂ along a Lower Permian fossil zone trending ENE-WSW. The neural network-based method was superior to a geostatistical method in spatial estimation accuracy and dealing with multivariate data. To evaluate uncertainty of the estimates, the method that draws several outputs by changing coordinates slightly from the target point and inputting them to the same trained network is proposed. The uncertainty differs with impurities, and is not based on just the spatial arrangement of data points. Influence-factor analysis of the network clarifies a strong effect of crystalline limestone on the P₂O₅ contents. Hydrothermal alteration, which could cause leaching and secondary concentration of phosphorus, is considered to have produced the effect.

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Copper-bearing deposits of China are statistically analyzed in terms of ore grade, metal amount and ore tonnage. Ore grade correlates to neither metal amount nor tonnage, while metal amount depends largely on tonnage. Each of grade, metal amount and tonnage shows more or less a lognormal distribution. Based on the ratio of copper in ore value (R_Cu), Chinese copper deposits are classified into two groups: mainly copper-producing deposits (MC : R_Cu ≥ 0.5) and accessorily copper-producing deposits (AC : R_Cu < 0.5). The grade-tonnage relation of MC deposits can be combined by two exponential functions approximating high grade (> 3.0%) and low grade (< 2.0%) parts. The critical copper grade, which is obtained from the low grade part of the relation, is 0.34%. Since less metal amounts are expected with decreasing ore grade below the critical grade, Chinese copper resources are concluded to become pessimistic, because some mines are working with grades close to this critical value. Taking account of the fact that many copper deposits are actually polymetallic, Cu-equivalent grades, which are converted from ratios of metal prices to the copper price, are also introduced. The critical Cu-equivalent grade of MC deposits (0.43%) is also suggesting that Chinese copper resources are pessimistic.

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Subcritical crack growth is considered to be a source of the time-dependent fracture in rocks. Thus, it is very important to know the nature of subcritical crack growth in rocks. Although rocks are generally anisotropic, rocks have been assumed as isotropic materials in many studies. Therefore, anisotropic properties of subcritical crack growth in rocks are not known well. In this study, Double-Torsion test was carried out using three kinds of granite to investigate the anisotropic properties and the grain-size dependency of subcritical crack growth. Double-Torsion specimens were prepared from each granitic rock with considering the propagation direction and the opening direction of the crack.
It was shown experimentally that the subcritical crack growth behavior in granite was anisotropic. When the crack advanced parallel to RIFT plane, the stress level at the crack tip was the smallest in all granite used in this study. Additionally, the stress level at the same crack velocity was in good agreement when the opening direction of the crack was the same.
It was also indicated that subcritical crack growth in granite was dependent on the grain size. For coarser grained granite, the stress level causing crack growth tended to be lower than that of fine-grained granite.
It could be considered that anisotropy and grain-size dependency of subcritical crack growth in granite related to the preferred orientation and the density of pre-existing microcracks, because it was recognized that as the velocity of P-wave propagating in the opening direction of the crack was low, that is, as the crack density of granite was high, the stress level causing subcritical crack growth was low. It can be concluded that the subcritical crack growth behavior in granite is affected strongly by the orientation distribution of pre-existing microcracks.

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Most in-situ data on rock stresses are from hard or moderately hard rock. It is necessary to develop a stress measurement method for soft rock, toward obtaining the in-situ stress state in such rock. We developed a stress meter that measures seven components of diametrical deformation and axial deformation in a pilot borehole during overcoring and records the measurements on a small data logger installed within it. From these deformation data, three-dimensional stress states in rock are determined using the observation equation derived from the analytical elastic solution. The stress meter is inserted into a 40-mm pilot borehole that can range in water content from dry to completely wet. The advantages of this stress meter are its smallness, ease of use, reusability, ability to measure at any borehole depth, and efficiency, since very little time is required for insertion and withdrawal and no time is needed to shift from insertion to overcoring. Moreover, elastic properties of the rock can be measured using the core in which the stress meter sits. Although the system is particularly suited to soft rock, it is applicable to any type of rock since the stress meter is highly sensitive.
Laboratory experiments simulated the functioning of the stress measuring system by using three welded tuff blocks (40 × 40 × 40 cm) with boreholes 40 mm in diameter at different orientations. The stress meter was inserted into the borehole and two cycles of uniaxial loading and unloading were carried out to simulate the stress relief. At same time, elastic properties of the rock were measured using the above-mentioned method. The calculated stresses were found to correlate closely with the applied stresses in all three cases, indicating that the stress meter functions well.

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The synergistic effect of the impurities on the critical current density for Zn deposition was investigated by measuring the polarization curves in the solutions containing different impurity elements. The critical current density for Zn deposition was significantly increased in the solution containing both Cu²⁺ and iron-group metal ions. It has been reported that the deposition of iron-group metals was suppressed in the presence of Zn²⁺ ions due to the adsorption of Zn hydroxide formed on the cathode. Since it was found that Co easily deposited on Cu area of coupled Cu-Zn electrode, the role of Cu is considered to promote the suppressed iron-group metals deposition by providing the iron-group metal ions with an active sites not adsorbed by Zn hydroxide. The synergistic effect of the impurities was also found in the solution containing a very small amount of Sb and iron-group metal ions. Sb existing in oxide state seemed to work as a catalyst to reduce the inherent deposition overpotential of iron-group metals. Thus, Cu²⁺ and Sb seem to promote the kinetically suppressed deposition rate of iron-group metals to decrease the hydrogen overpotential of cathode substrate, resulting in the increase in the critical current density for Zn deposition.

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The effects of alcohol addition on the electrolytic behaviors by using Pb-Ag-Ca anodes in sulfuric acid electrolyte and industrial electrolyte for zinc electrowinning were investigated. The electrolysis additives used in the sulfuric acid electrolyte were methanol, ethylene glycol and glycerin. In the case of industrial electrolyte, ethylene glycol was added. The results are summarized as follows.
Addition of each alcohol in the sulfuric acid electrolyte reduced the bath voltage and anode potential with increasing in the content of additives. Also, the bath voltage and anode potential decreased with increasing in the content of Ca in Pb-Ag-Ca anodes.
To predict the oxidation reaction mechanism of ethylene glycol addition, glyoxal and oxalic acid which are oxide substances of ethylene glycol were added in the sulfuric acid electrolyte. The anode potential and the quantity of gas generated decreased with increasing concentration of each additive. During the glyoxal addition, the trend of gas generated similar to the addition of ethylene glycol. It was considered that the anode reactions were oxidation of ethylene glycol or its substances.
Addition of ethylene glycol in the industrial electrolyte reduced the bath voltage and anode potential. Moreover, by using a Pb-Ag-Ca alloy anode, the bath voltage and the Pb contents in cathode zinc decreased compared with the conventional Pb-Ag anode.

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In electrokinetic soil remediation, contaminants are removed from soil and groundwater by the action of an electrical potential applied across electrodes embedded in the contaminated medium. An important advantage of electrokinetic soil remediation over other in-situ processes such as soil flushing is the capability to control over the movement of the contaminants. As the motion of the contaminants is confined by the electric field, there is little dispersion outside the treatment zone. Furthermore, the process is effective for soils with low and variable permeability. Soluble substances can be removed effectively by electroosmosis and ionic migration. However, contaminants that are adsorbed on the soil or are present as precipitates can not be effectively removed. In particular, the solubility of most heavy metals may be significantly reduced at elevated pH values. When impurities such as iron oxides are present, electorokinetics alone may not be effective in the extraction of heavy metals due to the higher acid / base buffer capacity. Also, acidification of the medium might cause large weight losses by dissolution of part of the solid matrix. It would, therefore, be better if the treatment were performed at neutral pH.
In the present study, the effectiveness of introducing complexing agents to enhance the removal of cadmium from kaolinite in the region of neutral pH by ionic migration is examined. The complexing agents selected were ethylenediaminetetraacetic acid (EDTA) and citric acid. The effectiveness of EDTA and citric acid for removing cadmium was investigated, and it was found that EDTA was more effective than citric acid. It was also found that the electrical potential applied across the electrodes played the important role in removing cadmium.

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Rapid collection and removal of gram-negative heterotrophic bacterial strain, Escherichia coli, was investigated by utilizing the interfacial interaction between cell and solid substratum. Both E.coli collection from stable suspension and its successive removal were performed by a column bed packed with fibrous ferro-nickel slag, which was employed as the collector media of bacterial cells. In the cell collection tests, little cell recovery was obtained at neutral pH condition where both E.coli and FS had negative surface potential. On the other hand, E.coli collection gradually increased as the pH decreased. These findings were explained by the suppression of electrostatic repulsive interaction between E.coli and FS led to an improvement in cell attachment to FS surface. Cell collection capacity Γ_max exponentially increased as the interfacial interaction energy minimum V_min became lower, indicating that surface characteristics played crucial roles in cell attachment mechanism. Moreover, part of the E.coli cells that had adhered to FS surface were effectively removed when the eluting solutions were alkaline conditions; hence reversible cell detachment from FS was possible by controlling the electro-repulsive force. Cyclic E.coli collection/removal tests demonstrated that cell collection and successive removal were repeatedly carried out al least six times, although about 40 mg of E.coli cell made a firm and irreversible attachment on FS. E.coli collection/removal behaviors in the present experiments were generally in good agreement with electrokinetic properties of cell and FS, suggesting that cell recovery based on surface characteristics is a promising method, especially for stable bacterial suspension.

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The material flow of lead in Japan is summarized including the information of the export and import of lead-acid battery and cathode-ray tube. The production of lead in 2000 was 353kt, 47% of which was produced from urban resources. Total consumption of the lead in 2000 was 347kt and some 3/4 was used for lead-acid battery. The recycling ratio of waste automobile batteries has been more than 95%, however the recycling system has some issues. The present paper discussed these issues, and compared a deposit-refund system, a lease system, and a recycle ticket system as the new system, We propose the deposit-refund system in order to prevent the diffusion of lead into the environment by decreasing illegal disposal and increasing collecting ratio of used car-battery. The system would be useful to obtain a sustainable and resource-recycling society using hazardous but useful lead.

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