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Shiina, Yoko*; Kinoshita, Ryo*; Funada, Shuhei*; Matsuda, Makoto; Imai, Makoto*; Kawatsura, Kiyoshi*; Sataka, Masao*; Sasa, Kimikazu*; Kaneko, Toshiaki*; Tomita, Shigeo*
Physical Review A, 110(6), p.062826_1 - 062826_7, 2024/12
Times Cited Count:0 Percentile:0.00(Optics)Alowasheeir, A.*; Eguchi, Miharu*; Fujita, Yoshitaka; Tsuchiya, Kunihiko; Wakabayashi, Ryutaro*; Kimura, Tatsuo*; Ariga, Katsuhiko*; Hatano, Kentaro*; Fukumitsu, Nobuyoshi*; Yamauchi, Yusuke*
Bulletin of the Chemical Society of Japan, 97(10), p.uoae099_1 - uoae099_7, 2024/10
Times Cited Count:3 Percentile:37.20(Chemistry, Multidisciplinary)no abstracts in English
Kusaka, Hiroyuki*; Ikeda, Ryosaku*; Sato, Takuto; Iizuka, Satoru*; Boku, Taisuke*
Journal of Advances in Modeling Earth Systems (Internet), 16(10), p.e2024MS004367_1 - e2024MS004367_38, 2024/10
Times Cited Count:2 Percentile:65.39(Meteorology & Atmospheric Sciences)To bridge the gaps between meteorological large-eddy simulation (LES) models and computational fluid dynamics (CFD) models for microscale urban climate simulations, the present study has developed a meteorological LES model for urban areas. This model simulates urban climates across both mesoscale (city scale) and microscale (city-block scale). The paper offers an overview of this LES model, which distinguishes itself from standard numerical weather prediction models by resolving buildings and trees at the microscale simulations. It also differs from standard CFD models by accounting for atmospheric stratification and physical processes. Noteworthy features of this model include: (a) the calculation of long- and short-wave radiations in three dimensions, incorporating multiple reflections within urban canopy layers using the radiosity method, and accounting for building and tree shadows in the simulations; (b) the provision of various heat stress indices (Universal Thermal Climate Index, Wet Bulb Globe Temperature, MRT, THI); (c) the assessment of the efficacy of heat stress mitigation measures such as dry-mist spraying, roadside trees, cool pavements, and green/cool roofs strategies; (d) the capability to run on supercomputers, with the code parallelized in a three-dimensional manner, and the model can also run on a graphics processing unit cluster. Following the introduction of this model, the study confirms its basic performance through various numerical experiments, including simulations of thermals in the convective boundary layer, coherent structure of turbulence over urban canopy, and thermal environment and heat stress indices in urban districts. The model developed in this study is intended to serve as a community tool for addressing both fundamental and applied studies in urban climatology.
Ji, T.*; Su, S.*; Wu, S.*; Hori, Yuta*; Shigeta, Yasuteru*; Huang, Y.*; Zheng, W.*; Xu, W.*; Zhang, X.*; Kiyanagi, Ryoji; et al.
Angewandte Chemie; International Edition, 63(25), p.e202404843_1 - e202404843_6, 2024/04
Times Cited Count:0 Percentile:0.00(Chemistry, Multidisciplinary)Nishio, Takahiro*; Ito, Keita*; Kura, Hiroaki*; Takanashi, Koki; Yanagihara, Hideto*
Journal of Alloys and Compounds, 976, p.172992_1 - 172992_8, 2024/03
Times Cited Count:3 Percentile:36.88(Chemistry, Physical)Miyagawa, Akihisa*; Hayashi, Naoki*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; Nakatani, Kiyoharu*
Analytical Sciences, 40(2), p.347 - 352, 2024/02
Times Cited Count:2 Percentile:11.65(Chemistry, Analytical)The Eu(III) distribution mechanism in single extractant-impregnated polymer-layered silica particle in a complex solution containing multiple lanthanide ions was investigated using fluorescence microspectroscopy. The rate-determining step was the reaction of Eu(III) with the two extractant molecules. The obtained mechanism and rate constants agreed with those of the single-ion distribution system, in which Eu(III) was distributed to the particles in the Eu(III) solution.
Tsumune, Daisuke*; Tsubono, Takaki*; Misumi, Kazuhiro*; Sakuma, Kazuyuki; Onda, Yuichi*
Pure and Applied Chemistry, 16 Pages, 2024/00
Times Cited Count:2 Percentile:57.75(Chemistry, Multidisciplinary)Twelve years after the Fukushima Daiichi Nuclear Power Station (F1NPS) accident, Cs activity concentrations have not yet decreased to pre-accident levels because of direct release from the site and fluvial discharges of
Cs deposited on land. It is necessary to consider dispersion processes in the coastal area to understand the impact of multiple river discharges and direct release. To achieve this goal, we carried out oceanic dispersion simulations that considered direct release and fluvial discharges and compared the results with the annual averages of observed data. We assumed that particulate
Cs discharged from rivers to the ocean quickly resuspended and re-leached after coagulation and precipitation and that all of the
Cs were dispersed. The reproducibility of results was improved by considering fluvial discharges of particulate
Cs at all sites between 2013 and 2016, except near the F1NPS. In other words, particulate
Cs discharged from rivers was found to influence the results of ocean surface activity concentrations within a relatively short period of time. The impact of direct release was dominant for the observed
Cs activity concentrations adjacent to the F1NPS, which was used to estimate direct releases.
Miyagawa, Akihisa*; Takahashi, Takumi*; Kuzure, Yoshiaki*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Watanabe, So; Sano, Yuichi; Nakatani, Kiyoharu*
Analytical Sciences, 39(11), p.1929 - 1936, 2023/11
Times Cited Count:1 Percentile:11.65(Chemistry, Analytical)In this study, we revealed the Eu(III) distribution in a single diglycolamide-derivative extractant (TODGA)-impregnated polymer-coated silica particle. The reaction of Eu(III) with two TODGA molecules in the polymer layer was the rate-limiting process, as evidenced by the absence of any correlation between the rate constants (k and k
) and concentrations of Eu(III) and HNO
.
Miyagawa, Akihisa*; Hayashi, Naoki*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; Nakatani, Kiyoharu*
Bulletin of the Chemical Society of Japan, 96(9), p.1019 - 1025, 2023/09
Times Cited Count:4 Percentile:34.10(Chemistry, Multidisciplinary)In the present study, we have elucidated the mass transfer mechanism of Eu(III) and Sm(III) in the solution with these ions in single nitrilotriacetamide (NTA) extractant-impregnated polymer-coated silica particle. The rate-limiting process of mass transfer was the reaction process of ions with NTA molecules, in which the NO ions were not involved, which was consistent with that obtained in single ion distribution system.
Nakanishi, Takumi*; Hori, Yuta*; Shigeta, Yasuteru*; Sato, Hiroyasu*; Kiyanagi, Ryoji; Munakata, Koji*; Ohara, Takashi; Okazawa, Atsushi*; Shimada, Rintaro*; Sakamoto, Akira*; et al.
Journal of the American Chemical Society, 145(35), p.19177 - 19181, 2023/08
Times Cited Count:5 Percentile:51.73(Chemistry, Multidisciplinary)Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Kaneko, Akiko*
Nuclear Engineering and Design, 409, p.112348_1 - 112348_15, 2023/08
Times Cited Count:1 Percentile:0.00(Nuclear Science & Technology)Miyagawa, Akihisa*; Hayashi, Naoki*; Kuzure, Yoshiaki*; Takahashi, Takumi*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; et al.
Bulletin of the Chemical Society of Japan, 96(7), p.671 - 676, 2023/07
Times Cited Count:7 Percentile:58.25(Chemistry, Multidisciplinary)We investigated the distribution mechanism of Eu(III) in a single polymer-coated silica particle including nitrilotriacetamide (NTA) extractants known as HONTA and TOD2EHNTA. The present study provides a valuable approach for the evaluation and enhancement of the functionality of "single extractant-impregnated polymer-coated silica particle".
Nakanishi, Takumi*; Hori, Yuta*; Shigeta, Yasuteru*; Sato, Hiroyasu*; Wu, S.-Q.*; Kiyanagi, Ryoji; Munakata, Koji*; Ohara, Takashi; Sato, Osamu*
Physical Chemistry Chemical Physics, 25(17), p.12394 - 12400, 2023/05
Times Cited Count:3 Percentile:42.17(Chemistry, Physical)Verma, V.*; Sakamoto, Shoya*; Ishikawa, Koichiro*; Singh, V. R.*; Ishigami, Keisuke*; Shibata, Goro; Kadono, Toshiharu*; Koide, Tsuneharu*; Kuroda, Shinji*; Fujimori, Atsushi*
Physica B; Condensed Matter, 642, p.414129_1 - 414129_5, 2022/10
Times Cited Count:5 Percentile:37.47(Physics, Condensed Matter)Kanzaki, Norie; Sakoda, Akihiro; Kataoka, Takahiro*; Sun, L.*; Tanaka, Hiroshi; Otsu, Iwao*; Yamaoka, Kiyonori*
International Journal of Environmental Research and Public Health, 19(17), p.10750_1 - 10750_14, 2022/09
Times Cited Count:1 Percentile:12.16(Environmental Sciences)Reactive sulfur species (RSS) involve oxidative stress deeply and contribute anti-inflammatory effect, but no studied have focused on RSS changes after irradiation. In this study, we comprehensively analyzed the metabolites, focusing on RSS in mouse brain following radon inhalation. The ratio of oxidized glutathione to reduced glutathione and proportion of RSS in GSH or cysteine increased by radon inhalation. The sulfur ion might bind to GSH or cysteine chemically under conditions of oxidative stress, even at very low-dose exposure. We performed the overall assessment of high-dimensional data by applying machine learning and showed the specific characteristics of the effects by the exposure conditions. Our results suggested that RSS could produce a biological defense against oxidative stress following radon inhalation.
Yamamura, Sota*; Fujiwara, Kota*; Honda, Kota*; Yoshida, Hiroyuki; Horiguchi, Naoki; Kaneko, Akiko*; Abe, Yutaka*
Physics of Fluids, 34(8), p.082110_1 - 082110_13, 2022/08
Times Cited Count:3 Percentile:30.82(Mechanics)Liquid spreading and atomization due to jet impingement in liquid-liquid systems are considered to be crucial for understanding the cooling behavior of high-temperature molten material in a shallow water pool. This phenomenon takes place when a liquid jet enters a pool filled with other immiscible liquid. The jet spreads radially after impinging on the floor while forming a thin liquid film and atomizing droplets. In this paper, we explain the result to quantify the unsteady three-dimensional behavior of the spreading jet by the employment of 3D-LIF measurements and 3-dimensional reconstruction. Under high flow velocity conditions, the phenomena of hydraulic jump and atomization of the liquid film occurred along with the spreading. To evaluate the spreading behavior, a comparison of the jump radius position of the liquid-liquid system as the representative value was made with the one calculated by the existing theory of a gas-liquid system. As the result, the spreading of the liquid film in the liquid-liquid system was suppressed compared with that in the gas-liquid system. Furthermore, the PTV method was successfully used to measure the velocity boundary layer and velocity profile in the liquid film, which are important factors that affect the spreading mechanism of the liquid film. These results revealed that in liquid-liquid systems, shear stress at the liquid-liquid interface causes a decrease in the flow velocity and suppressed the development of the velocity boundary layer. Also, to evaluate the atomization behavior, the number and diameter distribution of the droplets were measured from the acquired 3-dimensional shape data of the jet. As the result, the number of droplets increased with the flow velocity. Based on these results, we concluded that the spreading of the liquid film is affected by such atomization behavior.
Miyagawa, Akihisa*; Takeuchi, Masayuki; Arai, Tsuyoshi*; Watanabe, So; Sano, Yuichi; Nakatani, Kiyoharu*
Bulletin of the Chemical Society of Japan, 95(4), p.566 - 568, 2022/04
Times Cited Count:3 Percentile:21.39(Chemistry, Multidisciplinary)We demonstrate that pKa of extractant impregnated in a polymer phase varies with the cross-linking degree and the coexistence of other extractants, which induces a change in the hydrophobicity of the polymer phase. The results presented herein will be beneficial for the development of novel solid-extraction adsorbents.
Kimura, Fumihito*; Yamamura, Sota*; Fujiwara, Kota*; Yoshida, Hiroyuki; Saito, Shimpei*; Kaneko, Akiko*; Abe, Yutaka*
Nuclear Engineering and Design, 389, p.111660_1 - 111660_11, 2022/04
Times Cited Count:4 Percentile:53.26(Nuclear Science & Technology)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:10 Percentile:61.73(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 AlMo
O
H
) are adsorbed by electrostatic interaction. Alumina dissolves slightly in an acidic solution to form AlMo
O
H
, 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.
Iwasawa, Yuzuru; Sugiyama, Tomoyuki; Abe, Yutaka*
Nuclear Engineering and Design, 386, p.111575_1 - 111575_17, 2022/01
Times Cited Count:5 Percentile:53.26(Nuclear Science & Technology)