One of the improvement techniques of effective thermal conductivity for metal hydride particles bed is a insertion of radial fins into the bed, by which the heat transfer characteristics and reaction kinetics can be enhanced. Rectangular fins are inserted from 3 to 6 into the metal hydride particles bed and hydrogen absorption amount of metal hydride has been measured by constant volume Sievert's method. Reaction kinetics is defined as a ratio of 80% of maximum hydrogen absorption over the absorption time when the amount of hydrogen absorption reaches its corresponding value. As the results, radial fins are useful for the enhancement of the heat transfer and reaction kinetics of metal hydride particles bed. Reaction kinetics of reactor with 6 fins can become two times faster than that without the fin.
A previous procedure to measure thermal diffusivity and thermal conductivity simultaneously using an inverse solution for one-dimensional unsteady heat conduction can be simplified by improving the inverse solution with moving window clearing the issue related to settlement of time left in previous one. The new procedure does not need any time when the temperature change starts at a sensor position and can simply choose a time duration during which the measured temperature change becomes larger than the required accurate temperature change. The measurement is usually completed within about 1 minute until the temperature rise at the thermocouple position reaches a certain temperature level which makes its error level lower than a couple of percents. This method has merit being independent of surface condition except for the requirement of two or three sensing positions in the material. The accuracy of the estimated values is also similar to the error level of sensor at the position.
Systematic dew and frost point data were required on the assumption that occlusions of pipes or instabilities of flow systems would occur due to condensation of high boiling point residual gases, such as water vapors, in high pressure hydrogen under rapid hydrogen filling processes in hydrogen stations for FCVs. Dew point measurement system with high pressure test cell utilizing cooled mirror technique with visible image analysis were designed and produced. Measurements with H_2+H_2O standard gases for detecting generation and growth of frosts on the mirror surface were carried out to verify basic functions of the system. Dew point estimation procedures for phase equilibrium systems with solid phases as condensed phases were also considered.
In Japan there have been contradictory feelings about her foreign policy. On the one hand there seems no need for any major change, since it suits Japan splendidly; on the other, there is persistent concern that she is vulnerable because she depends upon resources over which she has very little control. Japan is a relatively small island country close to the Asian mainland. She has few natural resources, but is highly industrialized. She is Westernized as a result of the success of industrialization, but the roots of her civilization are in Asia and she still retains Asian characteristics in her culture. The growth of Japanese economic power, due to continuous, rapid development, has itself changed the situation. It has increased both the vulnerability and the influence of Japan. Twenty years ago, strangely enough, she was less vulnerable economically than she is now.
A weld-line is known as a representative defect in the field of plastic injection moulding, and also as a cause of inferior mechanical propensities and poor appearance. Heating and cooling mould systems, which cost extremely high, are a typical technology to prevent the weld-line. It is important to avoid weld-line defects easily and efficiently during the moulding process. Therefore, low cot design methods that enable to prevent weld-lines are demanded. A weld-line usually is generated at a meeting point of two or more flow fronts of molten resin in a mould, where the flow fronts are solidified and not fully contacted. The authors investigated the effect of the sub-gate which was designed to stir the meeting point and to suppress the weld-line using CAE. Since it is relatively easy to predict weld-line occurrence points by CAE, it is realistic to locate a sub-gate. This study intends to report on the following relevances: ‘Weld-line length and sub-gate geometrical conditions’, ‘Weld-line length and temperature conditions’ and ‘Occurrence trend of weld-lines and flow patterns’.
An Optical Wave Microphone System (O.W.M.S) is a new sound measuring device which need not install a device directly at measuring point like a condenser microphone and need not mix particulate materials like Leaser Doppler Velocimetry. Therefore O.W.M.S can measure sound without disturbing sound fields. Study on the reduction of jet noise has already been carried out, and the Perforated Tube could decrease jet noise at high pressures. However at low pressure peculiar sound noises were detected. Now this paper report our study of investigation concerning directional characteristics of jet noise of perforated tube in the field around the jet nozzle by using new measuring method of an Optical Wave Microphone System.
