• Transactions of Materials Processing
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• v.7 no.2
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• pp.177-185
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• 1998

The kinematically admissible veolcity field is developed for the shapes of dead metal zone and the curving velocity distribution in the eccentric plane dies extrusion. The shape of dead metal zone is defined as the boundary surface with the maximum friction constant between the deformable zone and the rigid zone. The curving phenomenon in the eccentric lane dies is caused by the eccentricity of plane dies. The axial velocity distribution in the plane dies is divided in to the uniform velocity and the deviated velocity. The deviated velocity is linearly changed with the distance from the center of cross-section of the workpiece. The results show that the curvature of products and the shapes of the dead metal one are determined by the minimization of the plastic work and that the curvature of the extruded products increase with the eccentricity.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.140-146
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• 2005

In this study, a quantitative environmental impacts assessment was performed for various power technologies with a lift cycle assessment (LCA) method. The LCA is regarded as a useful tool far analyzing diverse environmental impacts at a local, regional, and global aspect. The investigated power plants such as nuclear, coal, and LNC power systems were selected because they took share over $90\%$ of domestic elec-tricity supply in Korea. Furthermore, a wind power technology was included as a representative energy source out of Korean renewable energy systems. According to the three geological aspects, environmental impacts had been categorized into eight types. For these impact categories, characterization had been carried out for comparing environmental burdens of power systems under consideration. Then, normalization had been done in order to gain a better understanding of the relative size among impact categories.