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Policies and measures for achieving a sustainable society have been proposed and established, one of which is to encourage longer product use through product design improvements described in the EU action plan for circular economy by European Commission (2015). Such product design improvements for longer product use probably require high-quality materials and retention and management of repair parts. These will lead to increase in production and management costs. Accordingly, the product design improvements for longer product use will also lead to product price increase which can be an incentive for longer product use. Therefore, analyzing impacts of product price increases on environment and economy in advance is beneficial to discuss achievements of a sustainable society. This study proposes an analytical framework for environmental and economic impacts of product price increases with a dynamic discrete choice model. Focusing on air conditioners in Japan as a case study, this study estimates impacts of the product price increase on product replacements of air conditioners. Based on the results, this study analyzed environmental (material consumptions and GHG emissions) and economic (monetary sales of air conditioners) impacts of the product price increase, and a trade-off among effects of the product price increase on the three factors are clarified.

Product lifetime extension would contribute to establishing a circular economy by reducing the environmental impacts of mass consumption. This study developed a product lifetime model that can explicitly deal with the proportion and the longer-use behaviors of different consumer segments. The developed model expressed the product lifetime distribution as the composite of two distribution functions for longer-use promoters and normal-use consumers. The model explicitly deals with two parameters of longer-use actions: increasing the proportion of longer-use promoters and prolonging product lifetimes. A scenario analysis with the developed model showed that if the proportion of longeruse promoters, who uses their products 1.4 times longer than normal consumers, increases to 20%, the domestic demand for new product and the EoL generation will decrease by approximately 5%–10%. The results demonstrated that the model can quantitatively analyze the effects on the domestic demand for new products and the EoL products generation by the tow parameters for longer-use actions. By incorporating this model into a material stock and flow analysis model, it will be possible to assess the effects of promoting longer-use of durable goods on natural resource consumption, greenhouse gas emissions, reduction of final disposal of wastes, etc

A two-stage quenching technique consisting of impact flattening of atomized supercooled liquid droplets caused the production of flaky amorphous powders with a thickness of 1 to 3μm and an aspect ratio of 20 to 300 in Co-, Fe- and Al-based systems. The flaky powders consist of an amorphous phase over the entire particle size range even in the alloy systems where no amorphous phase is formed in the particle size below 25μm by high-pressure gas atomization. The improvement of the production ratio of the amorphous powders is due to the following three factors; (1) the second-stage cooling of supercooled liquid droplets, (2) the reduction of powder thickness to 1 to 3μm, and (3) the high thermal conductive state between rotator and powder resulting from the high-energy collision. The flaky powders also have smooth surface and edge combined with a uniform thickness, leading to good luster, high reflection ratio against light, high corrosion resistance, high mechanical strength and anisotropic magnetic properties. Furthermore, the unique morphology causes a high laminating tendency in a resin. By utilizing these advantages, the flaky amorphous powders are expected to be used as magnetic filler and corrosion-resistant coating materials.

Al-Mn and Al-Cr quasicrystalline and Al-Mn crystalline alloys were prepared by melt-quenching and their electrical resistivities were studied. The quenched samples exhibited an extremely high resistivity because of nonperiodic potential scattering and resonance scattering of the Fermi electrons. The temperature dependence of electrical resistivity of Al-22.5%Mn quasicrystalline was tried to fit by several models, and it was found that the plots of lnT (from 4.2 to 20 K) and T^2 (from 20 to 60 K) showed a straight line. The electrical resistivity of Al_6Mn crystalline alloy showed a linear temperature dependence over wide high temperatures, but that of Al_4Mn crystalline alloy showed a deviation from the linearlity. The values of P of the quasicrystalline alloys were larger than those of the crystalline counterparts.