Nichias (Japan)

<div class="section abstract"><div class="htmlview paragraph">To reduce cabin noise and vehicle weight (for lower fuel consumption), a lightweight soundproofing cover was developed as a countermeasure to sources of noise, using the Biot theory (vibration propagation theory in poroelastic materials). This report also presents the results of its application to a metal belt-type continuously variable transmission (CVT) used in Toyota Motor Corporation’s 2.0L vehicles.</div></div>

At Fukushima Dai-ichi nuclear power plant zircaloy that was used for cladding tube was exposed to high temperature steam and Hydrogen was produced by rapid oxidation. Essentially produced oxygen had to be sealed in containment vessel and released to the air by venting. However Hydrogen released from containment vessel were stored in reactor building and exploded at the NPP. From the experience engineers recognized that countermeasure to prevent Hydrogen leak from containment vessel was required. Unfortunately there are few studies relevant to Hydrogen permeability at high temperature and demanded Hydrogen permeability coefficient of sealing material in the case of high temperature exposure. In this study tests were conducted to predict Hydrogen permeability through rubber gasket at ACCIDENT. Experimental conditions were 1) deteriorated by heat, 2) deteriorated by heat and steam, 3) at high temperature. Tests were conducted for Silicone rubber, EPDM, NBR and Fluoro-rubber and we found that there was no significant difference between the rubbers Hydrogen permeability coefficient under conditions from 1) to 3) without the case of losing its elasticity. Currently we can present basic data to predict Hydrogen leak volume from containment vessel to reactor building at ACCIDENT. Based on the data we calculated Hydrogen leak volume from containment vessel through top flange of Fukushima Dai-ichi nuclear power plant in the case that zircaloy was melted completely as example.

It is known that bolt forces reduce significantly after tightening bolted flanged connections in which expanded PTFE gaskets are used. Bolts are often post-tightened in practice after a while to compensate for the reduction of bolt forces. The viscoelastic characteristic of expanded PTFE gaskets is the main cause for the phenomenon. However, the long term effects of the post-tightening on the residual bolt forces and the sealing performance of flanged connections have not been clarified yet. In this study, two sets of flanged connections (2 inch in nominal size), in which PTFE gaskets were used, were prepared and tightened. One of the flanges was post-tightened after a designated time. The reduction of bolt forces and the change in the sealing performance were measured for about two months. The results were compared with those of flanges without post-tightening. Based on the test results, the effectiveness of post-tightening was discussed from the viewpoint of the residual bolt force and the sealing performance. It has been clarified that the effectiveness of post-tightening depends on gasket material and that post-tightening is effective for expanded PTFE gaskets.

not Available.

While the current standard for NA (Numerical Aperture) for the semiconductor resist process is 193 nm High NA, use of the 193 nm immersion exposure process is growing and almost ready for application in mass production. With the growing trend toward the use of finer line processes in the manufacture of semiconductor devices, the need for cleanliness of the ambient atmosphere surrounding the silicon wafer has also been increasing. In addition to ammonia, that has hitherto been the main target for elimination, the concentration of other chemicals, such as amines and N-methyl-2-pyrrolidone (NMP), need to be kept sufficiently low for the new processes. Therefore, the role of chemical filters has become an essential one. We conducted a study on the dependency of chemical filters on the molecular diffusivity of target gas species, and, based on this data, developed a filter that eliminates amines. The filter has a honeycomb structure with a wide gas-contacting area, and consists of an ion-exchange resin that has received special treatment. The filter has a greatly improved gas capture efficiency (>99.8% for ammonia, >98% for triethylamine and NMP) and a very large adsorption capacity, which enables a 50% reduction of the filter volume compared with currently available chemical filters.

The Japan Sooiety of Meohanioal Engineers 412Al203 AZ91D MMC