Japan is lacking in energy rssources, but has many energy consuming industries which used to contribute largely to the national revenue before the first oil shock. Since the first oil crisis, the Japanese Governmsnt has taksn a long rangs view and spent much of its funds for research and development activities not only on energy resources and many energy-conserving ways and processes adequate to Japanese energy conditions, but on basic researches that should provide the foundation of the projects for practical uses. An outline of the results obtained so far of the projects is explained. Industries such as steel, chemical and the like that consume much energy have been making serious and practical efforts in R & D and greatly contributing to the reduction of energy consumption and oil import. The representative examples are described.

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Magnetic recording is potentially superior to optical recording with respect to recording density. However, to realize the full potential of magnetic disk storage devices, it is necessary to lower the head flying height from the submicrometer range to the sub-submicrometer range. In order to maintain the head at a safe sub-submicrometer flying height, it is necessary to solve the problem of head and medium wear. Consequently, the study of micro-tribology is essential for the development of magnetic recording capability. Compared with magnetic disk drives, optical disk drives have longer seek times and lower data rates. To enhance the seek time and data rate, electromechanics and servo-control technologies are the main concern. Advances in magnetic disk storage devices can be expected in the area of fixed-media on-line files. In contrast, the strong point of optical disk storage devices is their media-interchangeability. New optical disk applications which exploit this special feature can be expected.

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The governing equations of dynamic problems of elastic-viscoplastic three-dimensional soil containing spherical cavities are formulated by means of bipolar coordinates, adapting constitutive equations of normally consolidated clay. The stress wave propagation in the ground containing a spherical cavity of 0.5 m diameter at a 5 m depth is analyzed by the method of direct integration of the basic equations of the problem, when an axisymmetric dynamic load is applied to the boundary of the cavity. In the calculation, the change in pressure with depth from the ground surface is also taken into account for the initial state of the soil.

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The Direct Regular Method is applied to BEM elastostatic analysis. In this method, the domain of the problem is discretized by defining freedoms on its boundary, as usual, but the load point of the fundamental solution is located outside the domain so that the singular integral can be avoided. Stress intensity factors for a crack and stress concentration for a hole are analyzed by this method and the usefulness and limit of this method are discussed in comparison with Direct BEM. It is shown that this method can give an accurate solution for these problems if the load points are arranged very near the boundary. It is found that this method is especially useful for the problem with a corner point where the tractions on both edges are unknown. This method can be used in combination with the Direct Method.

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This paper proposes a branch-and-bound technique which generates stochastically dominant structural failure modes by using a lower bound of the complete failure path probability. Combinatorial properties of the failure paths are clarified and it is shown that there are many complete failure paths in a large-scale structure with a high degree of redundancy. Then, in order to reduce the number of computations, heuristic operations are applied to the branch-and-bound algorithm. Finally, the validity of the heuristic operations is demonstrated through numerical examples.

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The usual gird method has the serious defect that the stress solution depends on the numerical integration path of stress derivatives. In this study, a new method, independent of the numerical integration of the stress derivatives, is developed for steady state axisymmetric extrusion; that is, on every small plastic region, mean stress distribution is approximated with a second order polynomial with respect to r and z, and considering the continuity of mean stress, unknown coefficients of all of these polynomials are evaluated with the least squares method of the mean stress derivatives. Lagrange's method is applied to this procedure together with the unit division method, which is similar to that used in the finite element method and as a result, the stress solution can be uniquely determined in a short calculation time.

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A versatile automated system for X-ray stress measurement, using a microcomputer, has been developed on the basis of conventional techniques and the fundamental study on X-ray stress measurement using the Gaussian curve method previously proposed by the author. The simultaneous control of the three stepper motors on the goniometer by three motor controllers allows both rapid measurement and the use of various measuring methods. The most appropriate method for each material is programmable in this system. Residual stress values of a hardened steel were measured by the iso- and side-inclination methods using the fixed time and fixed count methods. They fell within a scatter band of the measured values. The η oscillation method proved to be most useful for the stress measurement of coarse grained steels. The system can also be used for evaluating diffraction line width using the Gaussian curve parameter.

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This paper describes the laminarization phenomenon of the flow in an axially rotating pipe when a fully developed turbulent flow is introduced into it. The rotating boundary layer is initially strongly stabilized by the centrifugal force due to the rotating velocity component, resulting in a laminarization of flow. This flow laminarization has been found to be more remarkable in the inlet region where a non-rotating inner core exists in the pipe section. The laminarized flow tends to be unstable as the flow goes downstream, and bursts of turbulence appear, which was also confirmed by the use of a flow visualization technique.

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This paper presents simplified approximate functions of the transfer functions of pressure gradient, mean flow velocity and centerline velocity in axially symmetrical laminar flow, and a new real time method of measuring unsteady flow rate and velocity by the use of an analog electronic circuit whose transfer characteristic is equivalent to the function. The simplified approximate functions are simple but highly precise, so their equivalent analog electronic circuits can be made easily. The unsteady flow rate and the centerline flow velocity obtained from the measured value of pressure difference in the pipe, by the use of the analog electronic circuit, are in good agreement with the results of numerical calculation and the value measured by LDA. The method presented in this paper makes simple but precise measurements of unsteady flow rate and velocity possible, and is very useful for practical application.

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The system instability of a centrifugal pump and pipe network is encountered in the high pressure systems of power plant. The frequency of the instability is limited to be very low (4HZ). Judging from the observation that this instability occurs at the pump operating point with a negative gradient of head-flow characteristics (stable characteristics) and with sufficient NPSH (Net Positive Suction Head), it is concluded that this is a new type of system instability, different from classical surging or cavitation surging. A series of experiments to solve the mechanism of this instability was carried out. The research program consisted of the measurement of the dynamic behaviour of the centrifugal pump, a confirmation test using a pipe network similar to that of the plant and the stability analysis of the system. Our result shows that the matching of the frequency of unstable pump impedance and the pipeline's resonant frequency results in this new type of system instability.

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The rotational speeds of stall cells in vaneleess diffusers and critical inlet flow angles for rotating stalls under the condition of no scroll were studied experimentally. Two experimental equations for rotational speeds are derived and a prediction method is presented. The predicted rotational speeds agree well with measured values in the literature. A simple equation for the critical inlet flow angle is derived from the experimental data. This equation is useful for predicting the onset of a rotating stall. In the experiment, a weak velocity fluctuation was found at the position of reverse flow on the diffuser wall just before the rotating stall. It is concluded that reverse flow in the cause of rotating stall in a vaneless diffuser. The conditions of reverse flow layers on the diffuser wall just before a rotating stall are made clear by a numerical analysis. The properties of a fully developed rotating stall are also presented.

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In this report, the bending moment in the root of a rotating blade was directly measured by strain gauges, and these experimental values were compared with the theoretical values estimated by annular momentum theory. In the experiment, a middle scale horizontal axis wind turbine having a diameter of φ6m was used. The maximum power of the turbine was 10 kVA. The number of blades was two. As a result, the following was found; (1) Both values (theoretical and experimental) agree well. (2) The mean values of flapwise moment in the blade root were about three times larger than those of chordwise moment. (3) The chordwise moment caused by the dead weight of the blade was very large compared with the chordwise moment caused by the fluid force. (4) The instantaneous moments in the blade root were about two times larger than those of the mean values per 1 minute.

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Thermo-hydraulic instability has been investigated experimentally in a boiling two-phase flow system composed of a vertical N-shaped boiling channel and an adiabatic bypass between an inlet plenum and an outlet plenum, using Freon 113. Instability caused by the blockage of flow by vapor, which cannot be found in Boure's classification of two-phase flow instabilities, has been observed. The flow maps in each section, static characteristics, stable flow limits and characteristics of this instability have been studied under various conditions to clarify the mechanism. The inlet velocity decreases when a vapor slug combining in the inverted U-shpaed bend obstructs the flow. The vapor slug flowing into the downcomer increases the void fraction in the downcomer, resulting in increased gravitational loss. Consequently, flow instability is brought about.

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NOx reduction effects by staged spray combustion in a high intensity swirl combustor have been investigated using kerosene with a pyridine content of 0-1.7%. The secondary air was radially injected into the combustion chamber through a multi-holed tube which was axially inserted from the rear side of a cylindrical combustor. Experiments have been carried out while varying the secondary air injection point, the primary to secondary air ratio, the pyridine content and the fuel flow rate. The main experimental results are as follows: (1) By effective mixing of a fine fuel spray with an air flow, with a large swirl degree, in the primary combustion zone, and by maintaining a suitable supply of secondary air, low NOx emission can be realized even in a high intensity combustion state. (2) The secondary air supply at a point where the primary combustion is almost completed is effective for reducing NOx emissions. (3) The primary to secondary air ratio for a suitable low NOx emission has a tendency to increase with a decrease in combustion intensity.

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The effect of the cylinder lubricating oil film on unburned hydrocarbon (HC) emissions from a spark ignition engine was investigated. A lubricant-free piston ring and cylinder were employed to study the interaction between the fuel and the oil film. Absorption and desorption of fuel vapor into and from the oil film was found to account for about 25-30 percent of the total unburned HC emissions. The variation of the concentration of combustion gases and unburned hydrocarbons in the combustion chamber and exhaust port were also studied, during the combustion, expansion and exhaust strokes, by means of high speed sampling valves. The HC concentration in the combustion chamber was found to increase during the expansion and exhaust strokes.

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This research aims to develop a technique to suppress liquid sloshing vibration in a tank by injecting air bubbles in a microcomputer-controlled manner. Using a rectangular tank 800 mm long, 1500 mm wide, and 500 mm high, installed on an oil-hydraulically controlled shaking table, sloshing was excited by a sinusoidal motion of the table and air was injected at each end of the test-tank bottom. The timing and duration of air injection were controlled by a microcomputer using the pressure signal caused by sloshing. Experiments showed that the most effective timing of air injection was the instant that the sloshing wave was ascending from the lowest position to the equilibrium one, and a small amount of air, equivalent to 1 to 3% of the water contained in the tank, was sufficient to suppress sloshing. A scaled-up test showed a similar effectiveness in reducing sloshing. An algorithm for controlling air-injection timing and duration was developed using knowledge obtained from the experiments.

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Dwell function generators are broadly applicable to several kinds of automatic machines because they do not need any special control equipment for positioning, and therefore have wider usage. In the present paper, Stephenson type 6-link crank-and-rocker mechanisms are studied. The conditions under which the output arms dwell at the edge points of rocking are analytically developed, and relationships between the dwell periods and mechanism parameters are clarified mνmerically by simulations. Such relationships are approximated by polynomials in the order of less than five, and using the dwell periods as design data, an automatic optimum synthesis of 6-link dwell mechanisms is carried out.

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Fretting damage morphology was investigated for SUS 304 stainless steel in a vacuum (4×10^-3Pa) by varying the number of fretting cycles, normal load, and slip amplitude, and the generation of surface cracks was examined by SEM. The condition for the generation of cracks and the crack morphology depended on both load and slip amplitude. Cracks were initiated at the boundary between fretted and unfretted areas after a certain number of cycles. Long cracks were formed under lower loads and short cracks were formed under higher loads at a constant slip amplitude. The length of a crack increased with an increase in slip amplitude, followed by a stop in crack generation at a certain slip amplitude under a constant load. The slip amplitude for the limitation of crack generation was approximately proportional to the load.

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The bulk temperature rise was studied when a moving heat source with variational heat quantity was applied repeatedly at regular intervals to the surface of an isotropic and homogeneous rectangular shaped body used as a model of a spur gear tooth. The effect of radiation at the inner surface of a boss on the bulk temperature rise is reduced as the distance between the inner surface of the boss and the working tooth flank is increased. The bulk temperature rise is almost inversely proportional to the heat supply interval. The size of the heat supply region and the moving direction of the heat source scarcely affect the bulk temperature rise. in a |νν^^-| range of not less than 1000, the bulk temperature rise is not affected by the moving velocity of the heat source, and the approximate bulk temperature rise can be obtained by dividing the temperature rise of the working tooth flank due to a stationary heat source by the number of teeth.

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A method for correcting measured coordinates with the error vector is proposed. The discrete distribution of the error vector, which is already know for the three-coordinate measuring machine used in the experiment, is utilized in this method. The correction method is as follows: (1) The measuring range is divided into the elements of a rectangular prism; (2) The error vector at any position in the element is calculated from interpo, lation; (3) and Measured coordinates are corrected with the error vector presumed from interpolation. Furthermore, measurements are made of both distance and flatness. The measured values obtained are corrected with the proposed method, and are found to be closer to the true values than those without correction. This correction makes the measuring error less than 3μm, and hence verifies the usefulness of the proposed method.

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An actual unmanned manufacturing station consisting of an NC machine and an industrial robot is assumed. The main hazards of the robot to a human, which occur during troubleshooting in an automatic operation mode, are enumerated using "Action-Chain-Models". Fault Trees of accidents caused by the hazards are given as subsets of "Logic Models for the Analysis of Accident-Causation-Mechanisms", and minimal cut structures are represented by Priority-AND gates to consider sequential properties of basic events. Furthermore, a manual safety mechanism, an automatic one, and a combination of the two, which cut off the power sources of the robot when a human enters a hazardous zone, are evaluated by comparing expected numbers of occurrences of the top events.

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