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伊與田 宗慶*; 松田 朋己*; 佐野 智一*; 茂田 正哉*; 菖蒲 敬久; 湯本 博勝*; Koyama, Takahisa*; Yamazaki, Hiroshi*; 仙波 泰徳*; 大橋 治彦*; et al.
Journal of Manufacturing Processes, 94, p.424 - 434, 2023/05
被引用回数：3 パーセンタイル：83.33(Engineering, Manufacturing)Aluminum alloys are increasingly being applied to automobile bodies to reduce the weight of automobiles. In joining steel materials and aluminum alloys using resistance spot welding (RSW), it is important to control the state of intermetallic compounds due to the temperature at the joining interface. In other words, in RSW of Fe/Al dissimilar materials, it is necessary to clarify the heating and cooling phenomena of the interface temperature during joining. Although the convection behavior of the molten aluminum alloy is thought to influence the temperature distribution at the joining interface, there are no studies that have directly observed this phenomenon. In this study, convection in molten zone of aluminum alloy during RSW of steel and aluminum alloy is discussed. Direct observations were attempted in order to clarify the convection behavior of the molten aluminum alloy in RSW of steel and aluminum alloy. The main feature of this experiment is that a real-scale test piece and an RSW apparatus used in actual production were used to observe convection during actual production. The observation experiments were conducted using synchrotron radiation X-ray at SPring-8. During welding, the specimens were irradiated with synchrotron radiation X-ray, and convection was observed from the behavior of tracer particles placed on the specimens. As a results, three types of convection were observed: radial outward convection from the center of the molten zone at the joining interface, convection from the edge of the molten zone toward its center, and weak circulating convection at the edge of the molten zone. And, small convection velocities were generated at the edge of the molten zone. Furthermore, the convection velocity inside the molten zone was calculated to be approximately 1.75 m/s. In addition, it was shown that there is a correlation between convection behavior and the shape of the molten zone.
椎野 佳祐*; 大友 季哉; 山田 武*; 有馬 寛*; 廣井 孝介; 高田 慎一; 三宅 純平*; 宮武 健治*
ACS Applied Polymer Materials (Internet), 2(12), p.5558 - 5565, 2020/11
被引用回数：23 パーセンタイル：77.93(Materials Science, Multidisciplinary)To achieve high-performance proton-exchange membranes (PEMs), understanding of the polymer structure/ property relationship is crucial. In particular, the structure of water clusters (number, size, interdomain distance, interconnectivity, etc.) and hydrophobic domains dominates important membrane properties, such as proton conductivity and mechanical strength, which can be adjusted by the monomer sequence in the polymer chains. In the present paper, we have prepared three sulfonated polyphenylene-based copolymers (SPP-MP, SPP-BP, and SPP-QP) whose main chain components were the same but their sequence differed by the use of different hydrophobic monomers (monophenylene, -MP; biphenylene, -BP; and quinquephenylene, -QP, respectively). Careful investigation of the proton nuclear magnetic resonance (1H NMR) spectra suggested that the randomness of the hydrophilic component (sulfophenylene unit) was dominated by the hydrophobic component: 51 % for -MP, 32 % for -BP, and 19 % for -QP, respectively. Transmission electron microscopy (TEM) observation of the three polyphenylene ionomer membranes revealed that the lower randomness of the hydrophilic component caused a larger hydrophilic domain size in their phase-separated morphology under dry conditions. Small-angle X-ray scattering (SAXS) measurements suggested that SPP-QP, with the lowest randomness of the hydrophilic component, possessed the most pronounced periodic structure under humidified conditions.
渡邉 一樹; 岡田 純平; 横田 知; 大山 大輔; 山田 貴史; 谷田部 仁史; 堀江 幸次; 内田 直樹
no journal, ,
使用済燃料のせん断工程では、使用済燃料の被覆管内のペレット(ウラン酸化物等)や被覆管の一部が砕けて粉末状になったもの(以下「せん断粉末」という。)がせん断機及び分配器の内部に滞留し、セル床上にも飛散していた。今回、工程洗浄の第一段階としてせん断工程から回収した、これらせん断粉末を2022年6月から9月にかけて溶解槽で溶解し核燃料物質を計量した。せん断粉末は微細な粉末状で表面積が大きく、溶解時に硝酸と急激に反応することで溶解槽の内圧が上昇し瞬時に正圧となり、溶解液のミスト等に含まれる核燃料物質が換気系統に移行する可能性があることから、内圧上昇を抑制する(9.98kPa以下で制御)運転モードにより、せん断粉末の溶解を行った。
横田 知; 岡田 純平; 渡邉 一樹; 谷田部 仁史; 山田 貴史; 堀江 幸次; 古内 雄太; 内田 直樹
no journal, ,
東海再処理施設は、運転再開を見越した状態で2014年に廃止措置へと移行したため、せん断処理工程内には使用済燃料せん断粉末(以下「せん断粉末」という。)等の核燃料物質が残存しており、廃止措置(除染、解体)を進めていくためには、工程洗浄としてせん断粉末を取り出す必要があった。せん断粉末の取出しでは、せん断機及び分配器の分解・清掃で回収したせん断粉末を濃縮ウラン溶解槽へ直接装荷するため、本操作に適した遠隔治具を考案し、セル内外でのモックアップ後に適用した。また、要領書及び体制を整備した上で操作訓練を入念に行うとともに、2007年から停止していた溶解槽等の機器設備の点検を計画的に実施することでせん断粉末の取出しの準備を完了させた。
