At the present time most of energy is derived from fossil fuels that have a finite reserve. To conserve these fossile sources and retain the present standard of living, a sythetie fuel derived from a renewable energy source must be used. Hydrogen, a fuel that can be produced from water and is expected to emit less pollutants, appears to be the answer. In this article the prospect of hydrogen usage in future is briefly reviewed.
The combustion characteristics of hydrogen are quite different from those of methane and other gaseous hydrocarbons. A novel property of hydrogen is its ability to react with oxygen in air when in contact with a catalyst. This property allows the fabrication of catalytic burners, that is, unusual flameless heating devices.
Research on hydrogen fueld internal combustion engines has progressed at a high rate in the last several years. Extensive tests on emissions and performance carried out using an injected reciprocating engine have revealed that the hydrogen engine can attain a compression ratio of 10 to 14 and emits less NO_x than gasoline engines. The first hydrogen gas turbine was a converted J-57 Pratt and Whitney engine. The stable operation of the J-57 confirmed that conventional gas turbines could be readily adapted to hydrogen fuel. Hydrogen-oxygen fueled rocket engines have been used successfully in recent years for the earth and moon orbits.
The efficiency for a modern steam power plan is 40% at the present stage and is not expected to increase significantly as long as the present type of boiler is used. However a new type of burner operating on hydrogen and oxygen would be able to increase this efficiency to 60%. Another new technology for power generation is fuel cell. Its main advantages are high efficiency and low emission level of pollutants. Hydrogen-oxygen fuel cells have shown to function excellently in some special applications particullary in spacecraft. Efforts are being given to produce fuel cells for general use.
The industrial-chemical hydrogen usage pattern will not be altered except that the input will be pipelined hydrogen rather than natural gas or naphtha. The conventional blast furnace-converter process for iron production would be changed by appearance of cheap hydrogen.

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The authors have already designed many types of thermodrills, which are now used for drilling hard rocks under the sea, and also represented the equation of local heat transfer coefficient, when the fire flame jet impinges normally to rock surface.
In thermal cutting of rocks, the local heat transfer coefficient will vary with the angle between fire flame jet and the rocicsurface.
This paper reports thermal characteristics (jet flame temperature, local heat transfer coefficient, and maximum heat flow rate) of jet flame impinging obliquely on the rock surface.
Moreover, the authors examined actual thermal cutting for granite and showed that the most effective angle between fire flame jet and rock surface was rectangular.

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An approach to optimum design for the energy consumption (kWh/ton-km) of hydraulic capsule transportation system was obtained from calculations as follows:
(1) There are the optimum capsule velocities that the energy consumptions are minimum for each pipe diameter. The larger the pipe diameter becomes the faster the optimum capsule velocity.
(2) As the linear line fill and material pack ratio to capsule are increased, the energy consumptions decrease.
(3) When the bulk density of materials are over 0.5, the value of the energy consumption shows nearly equal.
(4) The energy consumption with steel capsule container shows lower value than the energy consumption with aluminum or plastic capsule container.
(5) As the maximum allowable working pressure becomes over 40kg/cm², the energy consumption rises rapidly.
(6) As coefficient of friction between pipe wall and capsule container is larger, the energy consumption becomes higher rapidly.
(7) Energy consumption of the hydraulic capsule transportation is as lower as belt conveyor compared with another means.

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This is the second of a series of papers dealing with the solid-liquid sedimentation phenomena in the hindered settling range.
In the previous paper experiments were performed about the settling of closely sized olivine suspensions.
Apparent Stokes diameters and distribution density functions were calculated from the density curves which were obtained by the sedimentation density measurement apparatus.
Authors discussed about the hindered settling phenomena from the distribution changes with varied solid concentrations.
This report dealt with olivine suspensions with finer size range to obtain closely coincident results with the previous article.
Considering the equilibrium of resistivity and gravity force acting upon the settling particles, authors obtained mean hindered settling velosity, V, of particles, xm.
v= (ρs-ρl) g/18η·x²m.(9)
Xm is the arithmetic mean of the particle size for the relevant distribution density function.
The proposed equation was examined and compared in reference to the velocity values as given by literatures.

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For a hydrodynamic approach to the collision between bubbles and solid particles in flotation cells fluctuation velocity and velocity correlation of liquid were measured using an electrode reaction method and the following results were revealed;
(1) the turbulent intensity was 0.2-0.4 in the mechanical cells and nearly 0.2 in the pneumatic cell,
(2) the Lagrange correlation function was approximated by exp(ar) in the intense turbulent region and approximated by exp (-βτ²) in the weak turbulent region,
(3) the mixing length was decreased with the larger air flow number because of the motion of dispersed bubbles,
(4) the space micro scale was a few mm. On the basis of these results the fluctuation velocity of the swarm of particles was numerically analysed. It was further confirmed that the turbulent shear stress was increased in proportion to the increase of the mixing energy.

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The oxygen sensor with solid electrolyte for the continuous determination of oxygen content in liquid copper is finding increasing application in the industries of continuous casting.
The present investigation was undertaken to find out a new available solid reference electrode instead of Pt-air electrode. The e.m.f.'s of the following oxygen concentration cells were measured in the temperature range of 1100-1250°C in air and degrees of stability of three kinds of solid electrodes in zirconia tubes were investigated.
Pt, Fe-Fe_xO/ Zr0₂ +CaO/ air, Pt [1] Pt, Ni-NiO/ ZrO₂ +CaO/ air, Pt [2] Pt, Co-CoO/ ZrO₂ +CaO/ air, Pt [3]
It was found that e.m.f.'s of the cells [2] and [3] decreased with time even with some protective device. On the contrary the cell [1] showed very stable e.m.f. that was in good agreement with theoretical value at 1100-for 150-200 hours without any protective device. It was also confirmed experimentally that the Fe-FexO mixture in the zirconia tube could be used as a reference electrode not only in air but in reducing atmosphere and could be used repeatedly several times in the temperature range of 710-1200°C. From these experimental results one might conclude that the oxygen probe with Fe-FexO reference electrode could be used for continuous monitoring of oxygen content in liquid copper.

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Molybdenum oxygen-containing solid-phase compounds were electrodeposited on the platinum cathode from the alkaline solutions containing sodium molybdate or ammonium molybdate under galvanostatic condition.
Bath composition and electrolytic condition were as follows:
Sodium bath: Na₂MoO₄·E₂H₂O (0.2M), NaOH (for adjusting pH10.5)
Ammonium bath:(NH₄) ₆Mo₇O₂₄·E₄H₂O (0.2M as Mo), NH₄OH (for adjusting pH10.5)
Current density: 50mA/cm², Temperature: 70°C
Black deposits were obtained from the sodium baths and black-brown deposits from the ammonium baths.
Structure of these deposits were investigated by studying the crystallization processes of the deposits. Thermal analysis curves, X-ray diffraction pattern, infra-red absorption spectra measurements and trymethyl-silylation of the deposits were carried out and following results were obtained.
As plated state, deposits were amorphous MoO₂-n (OH) _2n (n; 0-2). Deposits obtained from the sodium bath contained Mo₆+and Na+. Deposits were dehydrated to crystallize as MoO₂, Na₂Mo₃O6.5 and small amount of Na₂MoO₄ with elevating temperature.
Deposits obtained from the ammonium bath contained NH4. Differing from the deposits obtained from the sodium bath, they scarcely contained Mo₆₊. Deposits dehydrated with vapouring NH₃ to crystallize as MoO₂ by elevating temperature.

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