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MnShimizu, Kazuyuki*; Nishimura, Katsuhiko*; Matsuda, Kenji*; Akamaru, Satoshi*; Nunomura, Norio*; Namiki, Takahiro*; Tsuchiya, Taiki*; Lee, S.*; Higemoto, Wataru; Tsuru, Tomohito; et al.
Scripta Materialia, 245, p.116051_1 - 116051_6, 2024/05
Hydrogen at the mass ppm level causes hydrogen embrittlement in metallic materials, but it is extremely difficult to experimentally elucidate the hydrogen trapping sites. We have taken advantage of the fact that positive muons can act as light isotopes of hydrogen to study the trapping state of hydrogen in matter. Zero-field muon spin relaxation experiments and the density functional theory (DFT) calculations for hydrogen trapping energy are carried out for AlMn. The DFT calculations for hydrogen in AlMn have found four possible trapping sites in which the hydrogen trapping energies are 0.168 (site 1), 0.312 (site 2), 0.364 (site 3), and 0.495 (site 4) in the unit of eV/atom. Temperature variations of the deduced dipole field width (
) indicated step-like changes at temperatures, 94, 193, and 236 K. Considering their site densities, the observed change temperatures are interpreted by trapping muons at sites 1, 3, and 4.
Fujita, Yoshitaka; Niizeki, Tomotake*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; Yamauchi, Yusuke*; Malgras, V.*; Kaneti, Y. V.*; Liu, C.-H.*; Hatano, Kentaro*; Suematsu, Hisayuki*; et al.
Bulletin of the Chemical Society of Japan, 95(1), p.129 - 137, 2022/01
Times Cited Count：8 Percentile：76.16(Chemistry, Multidisciplinary)In this work, the mechanisms responsible for the adsorption of molybdate ions on alumina are investigated using in-depth surface analyses carried out on alumina specimens immersed in solutions containing different molybdate ions at different pH values. The obtained results reveal that when alumina is immersed in an acidic solution containing molybdate ions, the hydroxyl groups present on the surface are removed to generate positively charged sites, and molybdate ions (MoO
or AlMoO
H
) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMoOH, which is more easily desorbed than MoO. Furthermore, the enhancement in the Mo adsorption or desorption property may be achieved by enriching the surface of the alumina adsorbent with many -OH groups and optimizing Mo solution to adsorb molybdate ions on alumina as MoO ions. These findings will assist researchers in engineering more efficient and stable alumina-based adsorbents for molybdenum adsorption used in medical radioisotope (
Mo/
Tc) generators.
Benu, D. P.*; Earnshaw, J.*; Ashok, A.*; Tsuchiya, Kunihiko; Saptiama, I.*; Yuliarto, B.*; Suendo, V.*; Mukti, R. R.*; Fukumitsu, Nobuyoshi*; Ariga, Katsuhiko*; et al.
Bulletin of the Chemical Society of Japan, 94(2), p.502 - 507, 2021/02
Times Cited Count：11 Percentile：66.97(Chemistry, Multidisciplinary)no abstracts in English
Bendo, A.*; Matsuda, Kenji*; Nishimura, Katsuhiko*; Nunomura, Norio*; Tsuchiya, Taiki*; Lee, S.*; Marioara, C. D.*; Tsuru, Tomohito; Yamaguchi, Masatake; Shimizu, Kazuyuki*; et al.
Materials Science and Technology, 36(15), p.1621 - 1627, 2020/09
Times Cited Count：8 Percentile：47.13(Materials Science, Multidisciplinary)Metastable phases in aluminum alloys are the primary nano-scale precipitates which have the biggest contribution to the increase in the tangible mechanical properties. The continuous increase in hardness in the 7xxx aluminum alloys is associated with the phase transformation from clusters or GP-zones to the metastable 
phase. The transformation which is structural and compositional should occur following the path of the lowest activation energy. This work is an attempt to gain insight into how the structural transformation may occur based on the shortest route of diffusion for the eventual structure to result in that of phase. However, for the compositional transformation to occur, the proposed mechanism may not stand, since it is a prerequisite for the atoms to be at very precise positions in the aluminum lattice, at the very beginning of structural transformation, which may completely differ from that of the GP-zones atomic arrangements.
Matsuda, Kenji*; Yasumoto, Toru*; Bendo, A.*; Tsuchiya, Taiki*; Lee, S.*; Nishimura, Katsuhiko*; Nunomura, Norio*; Marioara, C. D.*; Lervik, A.*; Holmestad, R.*; et al.
Materials Transactions, 60(8), p.1688 - 1696, 2019/08
Times Cited Count：14 Percentile：63.04(Materials Science, Multidisciplinary)no abstracts in English
Saptiama, I.*; Kaneti, Y. V.*; Yuliarto, B.*; Kumada, Hiroaki*; Tsuchiya, Kunihiko; Fujita, Yoshitaka; Malgras, V.*; Fukumitsu, Nobuyoshi*; Sakae, Takeji*; Hatano, Kentaro*; et al.
Chemistry; A European Journal, 25(18), p.4843 - 4855, 2019/03
Times Cited Count：15 Percentile：55.35(Chemistry, Multidisciplinary)The effective utilization of various biomolecules for creating a series of mesoporous boehmite (
-AlOOH) and gamma-alumina (-Al
O
) nanosheets with unique hierarchical multilayered structures is demonstrated. The nature and concentration of the biomolecules strongly influence the degree of the crystallinity, the morphology, and the textural properties of the resulting -AlOOH and -AlO nanosheets, allowing for easy tuning. The hierarchical -AlOOH and -AlO multilayered nanosheets synthesized by using biomolecules exhibit enhanced crystallinity, improved particle separation, and well-defined multilayered structures compared to those obtained without biomolecules. More impressively, these -AlOOH and -AlO nanosheets possess high surface areas up to 425 and 371 m
/g, respectively, due to their mesoporous nature and hierarchical multilayered structure. When employed for molybdenum adsorption toward medical radioisotope production, the hierarchical -AlO multilayered nanosheets exhibit Mo adsorption capacities of 33.1
40.8mg-Mo/g.
Nishimura, Katsuhiko*; Matsuda, Kenji*; Lee, S.*; Nunomura, Norio*; Shimano, Tomoki*; Bendo, A.*; Watanabe, Katsumi*; Tsuchiya, Taiki*; Namiki, Takahiro*; Toda, Hiroyuki*; et al.
Journal of Alloys and Compounds, 774, p.405 - 409, 2019/02
Times Cited Count：3 Percentile：17.96(Chemistry, Physical)
hydrogen partitioning controlToda, Hiroyuki*; Yamaguchi, Masatake; Matsuda, Kenji*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; Su, H.*; Fujihara, Hiro*; Ebihara, Kenichi; Itakura, Mitsuhiro; Tsuru, Tomohito; et al.
Tetsu To Hagane, 105(2), p.240 - 253, 2019/02
Times Cited Count：0 Percentile：0(Metallurgy & Metallurgical Engineering)no abstracts in English
Fukumitsu, Nobuyoshi*; Yamauchi, Yusuke*; Saptiama, I.*; Ariga, Katsuhiko*; Hatano, Kentaro*; Kumada, Hiroaki*; Fujita, Yoshitaka; Tsuchiya, Kunihiko
Isotope News, (760), p.15 - 18, 2018/12
no abstracts in English
Saptiama, I.*; Kaneti, Y. V.*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Fukumitsu, Nobuyoshi*; Sakae, Takeji*; Kim, J.*; Kang, Y.-M.*; Ariga, Katsuhiko*; Yamauchi, Yusuke*
Small, 14(21), p.1800474_1 - 1800474_14, 2018/05
Times Cited Count：51 Percentile：89.35(Chemistry, Multidisciplinary)no abstracts in English
Saptiama, I.*; Kaneti, Y. V.*; Oveisi, H.*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Takai, Kimiko*; Sakae, Takeji*; Pradhan, S.*; Hossain, M. S. A.*; Fukumitsu, Nobuyoshi*; et al.
Bulletin of the Chemical Society of Japan, 91(2), p.195 - 200, 2018/02
Times Cited Count：43 Percentile：81.72(Chemistry, Multidisciplinary)no abstracts in English
Saptiama, I.*; Kaneti, Y. V.*; Suzuki, Yumi*; Suzuki, Yoshitaka; Tsuchiya, Kunihiko; Sakae, Takeji*; Takai, Kimiko*; Fukumitsu, Nobuyoshi*; Alothman, Z. A.*; Hossain, M. S. A.*; et al.
Bulletin of the Chemical Society of Japan, 90(10), p.1174 - 1179, 2017/10
Times Cited Count：44 Percentile：79.84(Chemistry, Multidisciplinary)no abstracts in English
Mo/Tc generator for the Mo/Tc domestic productionFukumitsu, Nobuyoshi*; Tsuchiya, Kunihiko; Ariga, Katsuhiko*; Yamauchi, Yusuke*
Isotope News, (742), p.20 - 24, 2016/02
no abstracts in English
Kizu, Kaname; Murakami, Haruyuki; Natsume, Kyohei; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Hamaguchi, Shinji*; Takahata, Kazuya*
Fusion Engineering and Design, 98-99, p.1094 - 1097, 2015/10
Times Cited Count：6 Percentile：45.92(Nuclear Science & Technology)Current feeder and Coil Terminal Box (CTB) for the superconducting magnets for JT-60SA were designed. Copper busbar from power supply is connected to the High Temperature Superconductor Current Lead (HTS CL), which is installed on the vacuum vessel called CTB. The superconducting current feeder is connected to the cold end of HTS CL, and is led to main cryostat for magnets. Trial manufacturing of crank shaped feeder to reduce the thermal stress was performed. The small tool which can connect soldering joint with vertical direction was developed. Insulation materials made by manufacturing condition showed sufficient shear stress. Since the all manufacturing process concerned was confirmed, the production of current feeder and CTB can be started.
Koide, Yoshihiko; Yoshida, Kiyoshi; Wanner, M.*; Barabaschi, P.*; Cucchiaro, A.*; Davis, S.*; Decool, P.*; Di Pietro, E.*; Disset, G.*; Genini, L.*; et al.
Nuclear Fusion, 55(8), p.086001_1 - 086001_7, 2015/08
Times Cited Count：31 Percentile：83.35(Physics, Fluids & Plasmas)The most distinctive feature of the superconducting magnet system for JT-60SA is the optimized coil structure in terms of the space utilization as well as the highly accurate coil manufacturing, thus meeting the requirements for the steady-state tokamak research: A conceptually new outer inter-coil structure separated from the casing is introduced to the toroidal field coils to realize their slender shape, allowing large-bore diagnostic ports for detailed plasma measurements. A method to minimize the manufacturing error of the equilibrium-field coils has been established, aiming at the precise plasma shape/position control. A compact butt-joint has been successfully developed for the Central Solenoid, which allows an optimized utilization of the limited space for the Central Solenoid to extend the duration of the plasma pulse.
Murakami, Haruyuki; Kizu, Kaname; Ichige, Toshikatsu; Furukawa, Masato; Natsume, Kyohei; Tsuchiya, Katsuhiko; Kamiya, Koji; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4201305_1 - 4201305_5, 2015/06
Times Cited Count：6 Percentile：34.26(Engineering, Electrical & Electronic)JT-60U magnet system will be upgraded to the superconducting coils in the JT-60SA programme of the Broader Approach activities. Terminal joint of Central Solenoid (CS) is wrap type NbSn-NbTi joint used for connecting CS (NbSn) and current feeder (NbTi). The terminal joints are placed at the top and the bottom of the CS systems. CS modules located at middle position of CS system need the lead extension from the modules to the terminal joint. The joint resistance measurement of terminal joint was performed in the test facility of National Institute for Fusion Science. The joint resistance was evaluated by the operating current and the voltage between both ends of the terminal joint part. Test results met the requirement of JT-60SA magnet system. The structural analysis of the lead extension and its support structure was conducted to confirm the support design. In this paper, the results of resistance test of joint and the structural analysis results of lead extension are reported.
Yoshida, Kiyoshi; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Kamiya, Koji; Koide, Yoshihiko; Phillips, G.*; Zani, L.*; Wanner, M.*; Barabaschi, P.*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4200806_1 - 4200806_6, 2014/06
Times Cited Count：13 Percentile：56.48(Engineering, Electrical & Electronic)The upgrade of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by Japan and EU in the BA agreement. All components of magnet system are now under manufacturing in mass production. The first superconducting EF conductor was manufactured in 2010 in Japan. First superconducting coil EF4 was manufactured in 2012. Other EF5 and EF6 coils shall be manufactured by 2013 to install temporally on the cryostat base before the assembly of the plasma vacuum vessel. CS model coil is fabricated to qualify all manufacturing process of NbSn conductor. The first TF conductor was manufactured in 2012. The cryogenic requirements for JT-60SA are about 9 kW at 4.5K. Each coil is connected through an in-cryostat feeder to the current leads located outside the cryostat in the CTB. A total of 26 HTS current leads are installed in the CTB. The manufacturing of the magnet system is in progress to provide components to assembly the Tokamak machine.
Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Chikaraishi, Hirotaka*; Natsume, Kyohei*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4200205_1 - 4200205_5, 2014/06
Times Cited Count：25 Percentile：72.88(Engineering, Electrical & Electronic)Central Solenoid (CS) of JT-60SA are designed with the NbSn cable in conduit conductor. CS model coil (CSMC) was manufactured by using the real manufacturing jigs and procedure to validate the CS manufacturing processes before starting mass production. The dimensions of the CSMC are the same as real quad-pancake. The cold test of the CSMC was performed and the test results satisfied the design requirements. These results indicate that the manufacturing processes of the JT-60SA CS has been established. In this paper, the development and the validation of the CS manufacturing processes are described.
Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Yoshizawa, Norio; Koide, Yoshihiko; Yoshida, Kiyoshi
IEEE Transactions on Plasma Science, 42(4), p.1042 - 1046, 2014/04
Times Cited Count：9 Percentile：37.63(Physics, Fluids & Plasmas)JT-60SA is full superconducting tokamak that was constructed in JAEA Naka site in corporation with JAEA and F4E. The central solenoid (CS) assembly in JT-60SA consists of 4 modules of superconducting solenoid which has outer diameter of 2m and height of 1.6m. The currents for each module were independently controlled. CS was designed to produce enough flux to control the plasmas with 5.5 MA during 100 sec. Superconducting conductor for CS consists of NbSn strands. The support structure for CS assembly consists of the tie-plates (inner and outer), buffer zones and key-blocks. CS must be cooled down to 4K before charging, and modules will be shrunk during this process. The support structure made of stainless steel was also shrunk at 4K. Thermal expansion ratio of stainless steel, however, is different from that of modules, which would result in the gap between modules and supports. In order to cancel this gap, pre-compress mechanism needs to be introduced in the support structure for CS assembly. Mechanical pressure for the pre-compress will be controlled by hydraulic rams that are set at the top of each support. During the pre-compress process in which both key-blocks clamp the modules, tension works at the tie plates. The support structure for CS assembly, especially tie plates, should have sufficient mechanical strength to withstand the stress induced by the pre-compress at room temperature, not only to withstand the electro-magnetic force which was produced during the plasma operation. Space for installation of CS assembly is limited by TF coils, so that cross section of tie-plate is also limited. Final structure was successfully designed to adopt the stainless steel with 0.120.17 wt% of nitrogen content (SS316LN) for the material of the main parts of support structure.
Kamiya, Koji; Furukawa, Masato; Hatakenaka, Ryuta*; Miyakita, Takeshi*; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koide, Yoshihiko; Yoshida, Kiyoshi
AIP Conference Proceedings 1573, p.455 - 462, 2014/01
Times Cited Count：5 Percentile：90.59(Thermodynamics)The thermal shield of JT-60SA is kept at 80 K and will use the Multi Layered Insulator (MLI) to reduce radiation heat load to the superconducting coils at 4.4 K from the cryostat at 300 K. Due to plasma pulse operation, the MLI is affected by eddy current in toroidal direction. The MLI is designed to suppress the current by electrically insulating every 20 degree in the toroidal direction by covering the MLI with polyimide films. In this paper, two kinds of designs for insulated MLI are proposed focusing on a way to overlap MLI. A boil-off calorimeter method and temperature measurement has been performed to determine the thermal performance of MLI. The design of electrical insulated thermal anchor between the toroidal field (TF) coil and the thermal shield is also explained.
