Resource saving is thought to be one of the concepts and the acts necessary for environmental preservation. However, resource saving and its effect were examined and discussed from historical, regional, value and ethical viewpoints. From a historical viewpoint, the conversion from a society that used mainly sustainable resources to a society that uses non-sustainable resources was considered. From a regional viewpoint, Japan as a special region where there are little non-sustainable resources and a lot of consumption was taken up, and the influence of monopoly of worldwide resources by Europe and the United States was considered. In addition, in terms of value, the size of the overall gain of the acquisition of resources between generations was considered, and from an ethical viewpoint, the North-South problem was mainly analyzed. Also, regarding the conversion between resources, as the first approximation, the possibility of converting a general material into energy such as oil was shown, and the examination was advanced based on this. And then, it was pointed out that resource had not been saved in terms of the construction of a sustainable society even in the Edo period when resource had generally been maintained.

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In this study, systematic in-situ tests along Suzuka tunnel were carried out to examine the drilling performance in case of drilling holes up to 50 m depth. Special care was taken to clarify the effect of hole length on drilling performance such as penetration rate, rotational torque and oil pressure applied to the rock drill.
Results can be summarized as follows;
1) Averaged penetration rate has a declining trend with increase of hole length. Energy of elastic wave is gradually decreasing while propagating rods. Averaged decrease of penetration rate was 1.5% per 3 m-length rod.
2) Averaged penetration rate fluctuated especially at 20m and 40m of hole length. It was considered that an interaction between piston movement and reflected wave from the bit caused this considerable amount of fluctuation.
3) Rotational torque has an increasing trend with increase in hole length and frictional resistance between drill rod and hole.

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Recently, small-diameter shallow tunnels are often constructed by using slurry pipe-jacking method. This is the sewage tunnel drivage method. This system involves the pushing or thrusting of a drivage machine through concrete pipes ahead of jacks. Chemical grout injection into the surrounding soil around the tunnel is carried out before/after the drivage and pushing processes. The purpose of the chemical grout injection is to maintain a permanent stability of the surrounding soil. However, the behavior of the chemical grout solution in the surrounding soil around the tunnel is not clarified.
From these points of view, a numerical simulation model was developed in order to clarify the behavior of chemical grout solution. This model consists of a set of non-linear partial differential equations, the flow equations and the mass transport equations. The flow equation considers the effect of viscosity variation of the injected grout solution. As a chemical grouting process was analyzed by using this model, the permeation and the distribution process of the injected chemical grout solution was clearly understood.
Moreover, the effectiveness of the chemical grout injection was evaluated by using non-linear FEM analysis. From this results, the relation between confining stress and Young's modules of the soil/grouted zone should be taken into consideration when the range of the grouted zone is designed.

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The experiments to observe formation and growth of CO₂ hydrate in model sediment was conducted and the following results were obtained.
(1) The CO₂ hydrate started to form under a state of supercooling. The temperature of the sediment in the hydrate-growth region gradually increased and finally reached the nearly thermodynamic equilibrium condition.
(2) The measurement of temperature distribution was effective to understand the location and the process of hydrate growth. The speed of hydrate growth in the direction of height was found to be 0.5-1.0cm/min under the experimental condition.
(3) A simple kinetic equation predicting the hydrate growth was constructed under the assumption that the driving force of hydrate growth was proportional to the fugacity difference, where the overall rate constant of hydrate growth K' for each experiment was estimated from the amount of CO₂ consumed. The value of K' showed the tendency of increase under the experimental condition having the larger area of gas-water contact.
These results can be used as basic data in the future study of CO₂ sequestration process into the sediment while gas recovery from natural methane hydrate.

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Authors are developing a thermal jet dryer for the purpose of weight and volume reduction and recycling of sludge dehydrated cake. In order to investigate the discharging characteristics of particles from the drying tank, which is disc type and set vertically, experiments using a cold model equipment with airflow at ambient temperature and calculations using a CFD software FLUENT were carried out. The following results were obtained. (1) Velocity and its tangential component of airflow in the tank are almost the same, so they could be measured by a one dimension anemometer. It suggests that the Rankine eddy is generated in the tank. (2) By calculations using FLUENT, tangential velocity and direction profile of airflow in the tank were almost corresponding to experimental ones. (3) After feeding particles in the tank, velocity of airflow has decreased. Therefore, particles could not circulate along the inner wall and took off from it. This phenomenon contributed to the discharge of particles from the tank, and it was shown by FLUENT using two-way coupling calculation for gas-solid multiphase flow. (4) Experimental and calculated average residence time of particles in the tank were in the order of hundreds seconds. They corresponded with each other when the horizontal velocity ratio of particles-wall collisions was between 0.8 and 0.9.

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The growth of the anodic oxide layer and electrolytic behavior of the Pb-0.5%Ag-xCa ( x = 0.4, 0.6 and 0.9mass%) anodes were studied in sulfuric acid solution for the as-cast specimen and the rolled-annealed materials. After 20 days of anodic polarization, the Pb-Ag-Ca ternary alloy anodes were compared with the Pb-1.0%Ag alloy anode conventionally employed in the practical operation of zinc electrowinning.
The bath voltage was at similar level or decreased for the ternary alloy anodes compared with the Pb-1%Ag anode without calcium, and systematically reduced with an increasing Ca content.
A trend is observed that the coverage of the anode surface mainly with dense layer of beta-PbO₂ makes the generation of anode slime less in comparison with the anodes having oxide layer consisting largely of alpha-PbO₂. Furthermore, it is noticed that the rolled-annealed alloys were associated by increased generation of anode slime at any calcium content and that the anode oxide layer on these alloys showed strong peaks coming from alpha-PbO₂ in their XRD spectra.
The observation of the cross section of the anode oxide layer indicated the thick oxide layer on the ternary alloy anodes with reduced generation of anode slime and development of cracks inside the oxide layer.
The CaPb₃ phase of less resistance against chemical attack was found to be distributed along the boundary of the lead-based alloy grains at 0.4 and 0.6% Ca content and, however, many CaPb₃ grains of large size appeared also inside the grains in the 0.9% Ca ternary alloy.
The Pb-0.5%Ag-0.4 to 0.6% Ca alloy seems to be most favorable for the reduced bath voltage and the minimized degradation of the anode material. The microstructure control by rolling and annealing the alloys is expected to affect the anode characteristics of the alloys.

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