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Research paper : Energy savings in transportation systems by weight reduction of their components (M. Sakamoto et al.)−130−Synthesiology - English edition Vol.2 No.2 (2009) AuthorsMichiru SakamotoGraduated from the School of Sciences, University of Tsukuba in 1980, and completed the doctorate at the Institute of Geosciences, University of Tsukuba in 1985. Doctor (Geology). Joined the Machinery and Metal Section, Kyushu National Industrial Research Institute, Agency of Industrial Science and Technology in April 1985, and worked on R&D of metal matrix composites. Appointed to the Materials Research Institute for Sustainable Development, AIST in August 2007, and transferred to AIST Chubu in November 2007. In this paper, clarified the non-combustion mechanism of the noncombustible magnesium alloy, and built and managed the collaborative network.Hidetoshi UenoGraduated from the Fukuoka Prefectural Ukiha Industrial High School in 1965. Joined the Machinery and Metal Section, Kyushu National Industrial Research Institute, Agency of Industrial Science and Technology in April 1965, and worked on the R&D of metal matrix composites. Became leader of the Environment Adaptable Alloy Development Group, Materials Research Institute for Sustainable Development, AIST in 2001. Worked steadily on lightweight metal materials, and developed a practical processing technology for metal matrix composites and succeeded in the realization of foamed aluminum. In this study, mainly worked on plastic forming process of noncombustible magnesium alloys.Discussion with Reviewers1 Positioning of magnesium alloysComment & question (Toshimi Shimizu, Coordinator AIST)The social value of this study is energy saving through weight reduction and improved efficiency of transportation machinery and machine components. However, it is unclear why magnesium is the target of research instead of the current core materials of iron, steel, aluminum, and CFRP that are mentioned in the text. In chapter 1, I think you need to clarify the positioning of magnesium as background for introducing the scenario.Answer (Michiru Sakamoto)The goal is to achieve weight reduction of transportation machineries at a different level than with the existing core materials such as iron, steel, and aluminum, by making magnesium noncombustible and establishing its position as a core material. There aren’t many materials that have the potential as core materials, and we consider magnesium as one of the few candidates.Considering the volume of transportation machineries that are the foundation of society, the material for their weight reduction must be a core material that can be supplied readily like iron, steel, and aluminum. Therefore, we selected magnesium from the perspective of a material having such a qualification as an industrial material. Qualitatively, there are many materials that can be considered lightweight. Also, I don’t think the existing transportation machinery system will be used in the future, and it is certain that a new system will emerge and the component materials may be totally different from the existing materials. However, considering the use as structural material, stability of supply equivalent to the existing iron, steel, and aluminum is necessary, and an assurance in terms of environmental load is also necessary.2 Creation of scenario with product realization in mindComment & question (Norimitsu Murayama, Advanced Manufacturing Research Institute, AIST)The point that is interesting from the viewpoint of synthesis is, when the noncombustible property of magnesium by addition of calcium was discovered, which elemental technologies you set for development and how you designed and planned your research toward product realization. Also, I am very interested in research after the refining technology. Did you select the reduced pressure method assuming the effect of the oxide film formed on the molten metal surface? Did you have refining of structure by extrusion, and the subsequent forging and rolling in mind when you initially wrote the scenario? I imagine there were many trials and errors. Isn’t the coexistence of trial and error and inevitability a characteristic of a scenario for material development?Answer (Michiru Sakamoto)Researchers like us are not very good at scenarios with product realization in mind, while it is routine for companies, and it is important to set up a scenario that leads to product realization most efficiently and at a shortest route possible. However, even if it is the shortest route, it won’t work if the route is “off the wall,” and a solid technological backing is important. I think that role can be filled by the collaborative organization of university and public research institutions. Here, for the collaborative organization to share a common scenario is important, and without a scenario, the researches will be scattered and they will be points without linkages.3 Energy saving effect by weight reduction of componentsComment & question (Toshimi Shimizu)The research progressed under the mission to achieve weight reduction of most moving things, and the main result is the cast material using noncombustible magnesium alloys that was employed as a shelf support in the state-of-the-art Shinkansen. Although I sort of understand the initial idea of weight reduction, I think the readers’ understanding will be bettered if you add some quantitative figures showing how much weight reduction or energy saving was accomplished by employing this shelf support.Answer (Michiru Sakamoto)Your indication that the contribution of weight reduction to energy saving will become clearer if we present actual figures is very true, and we are keenly aware of this point. However, showing the energy saving effect is not so easy. For example, in our joint research with a certain automobile manufacturer, clear difference was measured between a magnesium piston and an ordinary aluminum piston in an engine bench test for a piston of the reciprocating engine. However, this is only a test, and the realization of the piston is still in a development stage. The weight of a Shinkansen is about 50 tons per compartment. The weight of the noncombustible magnesium shelf support is 15 kg. Direct comparison is difficult since this is not a direct replacement of aluminum parts to magnesium and there was a change in design, yet the weight reduction is about 7.5 kg in total. In the state-of-the-art Shinkansen car project, the primary goal was weight reduction of 500 kg per compartment. Although it is only 7.5 kg, there was some contribution, and the vehicle manufacturer was very grateful. It is difficult to see the effect of this weight reduction now, but I think it will eventually become a common material that will be used normally in various components in the future.4 Industry-academia-government collaboration scheme

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