PRESENT STATUS OF POWDER TECHNOLOGY EDUCATIONAL PROGRAMS AND RESEARCHES IN JAPAN

Tables to indicate the present status of powder technology educational programs in Japan are presented on the basis of a questionnaire style investigation by the Society of Powder Technology, Japan. Research activities in universities and research institutes are also included in the tables.

The activities of both the Society of Powder Technology and the Association of Powder Process Industry and Engineering in Japan are also introduced by explaining their organizations and annual events.     

A High‐Efficiency Single‐Phase Utility Interactive Inverter with an Active Power Decoupling Function and its Control Method

The present paper introduces a single‐phase utility interactive inverter with a power decoupling function. In a conventional single‐phase inverter, power pulsation at twice the grid frequency appears in the input power. Hence, electrolytic capacitors having large capacitances have been connected to the DC input terminal to stabilize the input DC‐bus voltage. Because the lifetime of the electrolytic capacitor is relatively shorter than that of another component, the lifetime of the inverter is affected by the capacitor. In order to prevent such a problem, a novel single‐phase inverter circuit with an active power decoupling function is introduced. The pulsating power on the input DC‐bus line and the pulsated energy on the input DC capacitor is transferred to the energy in a small film capacitor. Hence, the extension of the inverter lifetime can be expected by substituting a small film capacitor for the large electrolytic capacitors. In addition, the loss in the power decoupling circuit is very small; hence, the reduction in the overall conversion efficiency of the inverter can be minimized. The effectiveness of the proposed method is verified using a 300 W experimental setup.     

FLOW PATTERNS THROUGH TUBE BUNDLES AND PARTICULATE FOULING ONTO CYLINDERS

ABSTRACT

The shear-stress distributions around cylinders in tube bundles were measured by means of the limiting current method and the flow inside the bundle was also visualized. In the case of the staggered bundle, the shear-stress distributions had two peaks by the effect of the jet streams generated at the front row spacing and the adjacent cylinder. While in the bundle with in-line arrangement, the front stagnant point was shifted about 30° downward and the traverse streams among the rows were observed. This traverse streams caused asymmetry of the shear-stress distributions with respect to the main flow axis.

These results were discussed in connection with the fouling experiments investigated in dusty air. Particle deposition around cylinders could be qualitatively predicted from the shear-stress distributions, namely particles tend to deposit at positions where are less shear-stress in both tube arrangements. The size of particle deposited on the wake zone was coarser than that near the stagnant point behind the third row in both arrangements.     

Determination of Inosine-5-Monophosphate in Fish Tissue with an Enzyme Sensor

An enzyme sensor for IMP consisted of immobilized enzymes and an oxygen electrode. A nucleotidase (E.C. 3.1.3.5.), nucleoside phosphorylase (E.C. 2.4.2.1.) and xanthine oxidase (E.C. 1.2.3.2.) were immobilized on a membrane prepared from cellulose triacetate, 1,8-diamino-4-aminomethyloctane and glutaraldehyde. Optimum conditions for IMP determination were pH 7.8, 30°C, a flow rate of 1 ml min⁻¹ and sample volume of 20 μl. A calibration curve for IMP was linear up to 15 mM. This sensor could be applied to the determination of IMP in meats of sea bass, mackerel, yellowfish and saurel. Good correlative results were observed between the values obtained by the sensor and the conventional method. The sensor was stable for more than 15 days at 5°C and 100 assays.