Stimulated by the global environmental issues, needs for a new manufacturing paradigm areincreasing. Such a new manufacturing paradigm should drastically reduce materials and energyconsumptions, while maintaining quality of life, product quality, and corporate profits. To investigate the feasibility of such a manufacturing paradigm, life cycle design is an indispensable tool.This article overviews the concepts of “life cycle simulation (LCS) systems”that are currentlydeveloped by various researchers. Case studies using the LCS system illustrate the possibility ofproduct life cycles that can reduce environmental loads while keeping corporate profits. LCS is alsouseful to consider product architecture as well as business strategies.
Physical service life of steel reinforced concrete (RC) components and buildings in the ordinary atmospheric surroundings is reasonably determined by the time when the occurrence of crack and spalling of cover concrete makes serious damage to the daily safety as the results of the progress of neutralization of concrete and the accompanying corrosion of reinforcing steel. If we make effective use of polymeric coating materials, however, the physical service life can be prolonged by their suppressive effects against the progress of neutralization and corrosion. I propose the rational setting methods of physical service life of reinforced concrete treated with polymeric coating materials based upon the concept of equivalent thickness of cover concrete and also equivalent corrosion loss of crack occurrence.
As the needs for eco-materials increase, it is essential to study and improve the thermoplastic elastomer because it is a representative recycle material. In order to make clear the practical recycle properties of the styrene type thermoplastic elastomer (TPS) substantially, we studied the changes in the material properties of TPS after it is aged thermally and repeatedly recycled without mixing any virgin component and additive. As a result, the following properties have been revealed. After the first and second thermal aging processes, the strength of TPS increases a little because molecular chains are distributed to fill sparse and weak parts. After the first recycle process, molecular chains restore. After the second recycle process, however, the binding strength of styrene molecular is clearly weakened. Moreover, oxidation-degradation progresses gradually in each thermal aging and recycle process, and the strength of TPS begins to decrease after the third aging process. Keywords Thermdplastic elastomer, Recycle, Styrene block, Etyhlene/butyhlene block