The contact stress distributions of pipe flange connections with larger nominal diameter (20”) and smaller nominal diameter (3”) including spiral wound gaskets under internal pressure are analyzed taking account non-linearity and hysteresis of the gaskets by using the finite element method (FEM) . The difference in the contact stress distribution is substantial between the pipe flange connections with the 20”nominal diameter and the 3”nominal diameter. The leakage tests were also conducted using the actual pipe flange connections with the 20”nominal diameter and the 3”nominal diameter including the spiral wound gasket. Using the contact stress distributions under the internal pressure, the values of the new gasket constants proposed by PVRC (Pressure Vessel Reseach Council) are estimated by taking account the changes in the contact stress. A difference in the new gasket constants is substantial between the PVRC values and the estimated results, which are obtained by using the initial clamping stress. However, the difference is small between the PVRC values and the estimated values, which are obtained by using the actual gasket stress under the internal pressure. In addition, a method for determining the bolt preload for a given tightness parameter is demonstrated. The differences in the bolt preload between the actual pipe flange connections and the PVRC values are substantial.

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It will be difficult to prevent the damage of tanks caused by a large earthquake even if extreme care has been exercised. Therefore, rational emergency responses will be required for preventing expansion into secondary disaster. In this paper, we propose a system that can estimate ground motion distribution in a whole of petroleum stockpiling base using a seismic record and evaluate damage of oil storage tanks just after an earthquake in order to support rational emergency responses. Spectral ratios of horizontal and vertical component of microtremor were used for relative evaluation of surface soil amplification. The system can assess the hazard for circumferential shell stress, axial shell stress, seismic capacity and liquid sloshing immediately using the ground motion at each tank site estimated from both the relative soil amplification factors and a seismic record at a petroleum stockpiling base just after a large earthquake.

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Next-generation lithographic technology needs not only high resolution but also high throughput, large process latitude and low cost. Nanoimprint lithography (NIL) is a major breakthrough in nano-patterning because it can produce nm feature size over a large area with a high throughput and low cost. In order to obtain high productivity, the mold requires durability for repeated NIL process and mechanical strength in a moment of contact with the substrate. Diamond is a candidate material for the above requirements, because diamond has numerous excellent properties such as large Knoop hardness, large compressive strength and low thermal expansion coefficient. Therefore, nanoimprint lithography using diamond mold was examined. The electron beam (EB) lithography and reactive ion etching (RIE) with oxygen gas were used to fabricate fine patterns in diamond mold. The dented line pattern with 2μm width and 340 nm depth was obtained using this process. This diamond mold was pressed to PMMA on silicon substrate and diamond substrate, and convex PMMA line patterns were replicated. Direct aluminum patterns were obtained by diamond mold at the pressure of 130. 8 MPa in room temperature.

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