Linking combustion-derived magnetite and black carbon; Insights from magnetic characterization of PM in downwind East Asia

Nozomu, Tsuchiya*; Ikemori, Fumikazu*; Kawasaki, Kazuo*; Yamada, Rena*; Hata, Mitsuhiko*; Furuuchi, Masami*; Iwamoto, Yoko*; Kaneyasu, Naoki*; Sadanaga, Yasuhiro*; Watanabe, Takahiro; et al.

Environmental Science & Technology, 59(21), p.10400 - 10410, 2025/05

https://doi.org/10.1021/acs.est.4c14187

Black carbon (BC) is a typical primary aerosol emitted from combustion. While its co-existence with iron oxides (FeO) has recently been reported, the extent of bias caused by FeO mixing to the BC observations is largely unknown. To identify the dominant FeO emission sources and associated overestimation of BC, magnetics properties of PM collected at a remote site in East Asia was investigated in combination with detailed isotopic and chemical analyses. Consequently, biomass burning events did not enhance aerosol magnetism as they did for the mass concentration of BC, whereas coal burning events coincided with periods of high magnetization. Therefore, magnetization/BC ratio is proposed as a highly selective indicator for identifying combustion sources (i.e. coal, oil or biomass burning).

Federated learning of creep rupture time and high temperature tensile strength prediction models

Sakurai, Junya*; Torigata, Keisuke*; Matsunaga, Manabu*; Takanashi, Naoto*; Hibino, Shinya*; Kizu, Kenichi*; Morita, Akira*; Inomoto, Masahiro*; Shimohata, Nobuaki*; Toyota, Kodai; et al.

Tetsu To Hagane, 111(5), p.246 - 262, 2025/04

https://doi.org/10.2355/tetsutohagane.TETSU-2024-124

Spontaneous magnetic field and disorder effects in BaPtAsSb with a honeycomb network

Adachi, Tadashi*; Ogawa, Taiki*; Komiyama, Yota*; Sumura, Takuya*; Saito-Tsuboi, Yuki*; Takeuchi, Takaaki*; Mano, Kohei*; Manabe, Kaoru*; Kawabata, Koki*; Imazu, Tsuyoshi*; et al.

Physical Review B, 111(10), p.L100508_1 - L100508_6, 2025/03

https://doi.org/10.1103/PhysRevB.111.L100508

Development of a dissolution method for analyzing the elemental composition of fuel debris using sodium peroxide fusion technique

Nakamura, Satoshi; Ishii, Sho*; Kato, Hitoshi*; Ban, Yasutoshi; Hiruta, Kenta; Yoshida, Takuya; Uehara, Hiroyuki; Obata, Hiroki; Kimura, Yasuhiko; Takano, Masahide

Journal of Nuclear Science and Technology, 62(1), p.56 - 64, 2025/01

https://doi.org/10.1080/00223131.2024.2381553

A dissolution method for analyzing the elemental composition of fuel debris using the sodium peroxide (NaO) fusion technique has been developed. Herein, two different types of simulated debris materials (such as solid solution of (Zr,RE)O and molten core-concrete interaction products (MCCI)) were taken. At various temperatures, these debris materials were subsequently fused with NaO in crucibles, which are made of different materials, such as Ni, AlO, Fe, and Zr. Then, the fused samples are dissolved in nitric acid. Furthermore, the effects of the experimental conditions on the elemental composition analysis were evaluated using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), which suggested the use of a Ni crucible at 923 K as an optimum testing condition. The optimum testing condition was then applied to the demonstration tests with Three Mile Island unit-2 (TMI-2) debris in a shielded concrete cell, thereby achieving complete dissolution of the debris. The elemental composition of TMI-2 debris revealed by the proposed dissolution method has good reproducibility and has an insignificant contradiction in the mass balance of the sample. Therefore, this newly developed reproducible dissolution method can be effectively utilized in practical applications by dissolving fuel debris and estimating its elemental composition.

Sm synchrotron-radiation-based Mssbauer and SR studies of SmRuGe

Tsutsui, Satoshi; Ito, Takashi; Nakamura, Jin*; Yoshida, Mio*; Kobayashi, Yoshio*; Yoda, Yoshitaka*; Nakamura, Jumpei*; Koda, Akihiro*; Higashinaka, Ryuji*; Aoki, Dai*; et al.

Interactions (Internet), 245(1), p.55_1 - 55_9, 2024/12

https://doi.org/10.1007/s10751-024-01900-6

Muon spin relaxation in mixed perovskite (LaAlO)(SrAlTaO) with

Ito, Takashi; Higemoto, Wataru; Koda, Akihiro*; Nakamura, Jumpei*; Shimomura, Koichiro*

Interactions (Internet), 245(1), p.25_1 - 25_7, 2024/12

https://doi.org/10.1007/s10751-024-01866-5

Large spontaneous Hall effect with flexible domain control in the antiferromagnetic material TaMnP

Kotegawa, Hisashi*; Nakamura, Akira*; Huyen, V. T. N.*; Arai, Yuki*; To, Hideki*; Sugawara, Hitoshi*; Hayashi, Junichi*; Takeda, Keiki*; Tabata, Chihiro; Kaneko, Koji; et al.

Physical Review B, 110(21), p.214417_1 - 214417_8, 2024/12

https://doi.org/10.1103/PhysRevB.110.214417

A Study on analysis of actual data in "Fugen" decommissioning

Koda, Yuya; Nakamura, Yasuyuki; Iguchi, Yukihiro*; Yanagihara, Satoshi*

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 10 Pages, 2024/11

https://doi.org/10.1115/ICONE31-135953

"Fugen" has been proceeding with decommissioning work since receiving approval for the decommissioning plan in 2008, and is currently in the second step of dismantling the reactor peripheral equipment. In decommissioning, project management is important to select strategies and optimize processes, waste, safety, costs, etc. In Japan, it is expected that decommissioning work for nuclear facilities will become more serious in the future, and the knowledge and project management data obtained from the decommissioning work carried out at "Fugen" to date will be useful for planning. Since the dismantling and removal of the main turbine equipment and the peripheral equipment in preparation for the reactors have been completed so far, the actual data has been organized and analyzed and compiled into unit work coefficients. The project management data, collected during the decommissioning work carried out at "Fugen" is organized and calculated as a unit work coefficient.

Effects of magnetic ordering on the ground-state energy of plutonium dioxide; A Study using adiabatic connection fluctuation-dissipation theory

Nakamura, Hiroki; Machida, Masahiko

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 5 Pages, 2024/11

https://doi.org/10.1115/ICONE31-134660

Efficiency and safety improvements in nuclear fuel development demand a comprehensive understanding of the thermal properties of PuO. Because of difficulty of experiments at high temperatures, they have been supplemented by numerical simulations, such as density functional theory (DFT). While DFT struggles to replicate the nonmagnetic insulating ground state of PuO, DFT+U can reproduce nonmagnetic insulating state. However, the obtained state remains less stable than magnetic states and is not the ground state. Adiabatic connection fluctuation-dissipation theory (ACFDT) is expected to be a promising solution, addressing higher-order correlations and exact exchange energies. In this study, we evaluate the ground state energy using ACFDT and find that the nonmagnetic state can be the ground state. This result successfully reproduces the observed nonmagnetic ground state of PuO and has the potential to improve predictions of the thermal properties of nuclear fuel materials.

Study on functional limitations of piping in industrial facilities (The Effect of initial plastic deformation on elbow piping)

Sugiura, Ayumu*; Furuya, Osamu*; Takito, Kiyotaka; Okuda, Yukihiko; Nakamura, Izumi*

Dynamics and Design Conference 2024 (D&D 2024) Koen Rombunshu, 11 Pages, 2024/09

no abstracts in English