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Journal Articles

Gravitational form factors of pion from top-down holographic QCD

Fujii, Daisuke; Iwanaka, Akihiro*; Tanaka, Mitsuru*

Physical Review D, 110(9), p.L091501_1 - L091501_8, 2024/11

 Times Cited Count:0 Percentile:0.00(Astronomy & Astrophysics)

The gravitational form factors (GFFs) of pions are calculated from a top-down holographic quantum chromodynamics (QCD) approach with momentum transfer dependence for the first time. It is important because the GFFs of hadrons have information on the internal stress distribution that may provide insight into the mechanism of how QCD forms hadrons. The forward limit value of this GFFs, i.e. the D-term, was also obtained. Furthermore, in this approach, we observe the so-called glueball dominance, in which pions have gravitational interactions via infinite glueball spectra.

Journal Articles

In-plane movement of isolated poly(methacrylate) chains on a hydrophilic solid surface

Kawano, Masayuki*; Morimitsu, Yuma*; Liu, Y.*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Kawaguchi, Daisuke*; Yamamoto, Satoru*; Tanaka, Keiji*

Macromolecules, 57(14), p.6625 - 6633, 2024/07

 Times Cited Count:0 Percentile:0.00(Polymer Science)

Journal Articles

Evaluation of thermodynamic model of Pd(II) complex formation with isosaccharinic acid

Kimuro, Shingo; Taneichi, Yayoi; Iwata, Hajime; Ishidera, Takamitsu; Kitamura, Akira; Tachi, Yukio; Tanaka, Takeru*; Hirano, Kana*; Hieda, Manami*; Miyabe, Shunsuke*; et al.

Journal of Solution Chemistry, 53(6), p.854 - 868, 2024/06

 Times Cited Count:0 Percentile:0.00(Chemistry, Physical)

Journal Articles

Characteristics of smartphone-wirelessly-connected personal dosemeters

Mikami, Satoshi; Tokiyoshi, Masanori*; Sato, Rina*; Tanaka, Daisuke*; Yoshimura, Kazuya

Nihon Hoshasen Anzen Kanri Gakkai-Shi, 23(1), p.10 - 17, 2024/06

Taisei Corporation and Infocube LAFLA Co., Ltd. have developed the smartphone-wirelessly-connected dosemeters, aiming to apply it to real-time exposure management of multiple decontamination workers. In order to grasp the basic characteristics of the developed dosemeters, they were calibrated and tested their characteristics such as energy dependency, angle of incidence dependency, etc. at photon calibration fields in Japan Atomic Energy Agency. The results showed generally good characteristics in each test. We evaluated that the dosemeters can be effectively used for decontamination work.

Journal Articles

Observation of high-pressure polymorphs in bulk silicon formed at relativistic laser intensities

Rapp, L.*; Matsuoka, Takeshi*; Firestein, K. L.*; Sagae, Daisuke*; Habara, Hideaki*; Mukai, Keiichiro*; Tanaka, Kazuo*; Gamaly, E. G.*; Kodama, Ryosuke*; Seto, Yusuke*; et al.

Physical Review Research (Internet), 6(2), p.023101_1 - 023101_18, 2024/04

It is generally known that irradiating a solid surface with a laser pulse of ultra-relativistic intensity generates a plasma on the surface, which in turn creates an ultrahigh pressure inside. In this study, the crystal structure analysis of high-pressure phases generated inside silicon single-crystals irradiated by this laser was performed using the diffraction system at the Stress and Imaging apparatus of BL22XU, which is a JAEA-BL. The results obtained confirm the existence of high-pressure phases that silicon is said to possess: body-centered, rhombohedral, hexagonal, and tetragonal phases in the interior. We can get the results that the crystal structure of silicon polymorphs of being include body-centered, rhombohedral, hexagonal-diamond, tetragonal exists. In the future, we will accumulate data and apply them to control the internal structure, strength, and functionality of materials.

Journal Articles

Validation of the $$^{10}$$Be ground-state molecular structure using $$^{10}$$Be($$p,palpha$$)$$^{6}$$He triple differential reaction cross-section measurements

Li, P. J.*; Beaumel, D.*; Lee, J.*; Assi$'e$, M.*; Chen, S.*; Franchoo, S.*; Gibelin, J.*; Hammache, F.*; Harada, T.*; Kanada-En'yo, Yoshiko*; et al.

Physical Review Letters, 131(21), p.212501_1 - 212501_7, 2023/11

 Times Cited Count:12 Percentile:90.93(Physics, Multidisciplinary)

The cluster structure of the neutron-rich isotope $$^{10}$$Be has been probed via the ($$p,palpha$$) reaction. The triple differential cross-section was extracted and compared to distorted-wave impulse approximation reaction calculations performed in a microscopic framework using the Tohsaki-Horiuchi-Schuck-R$"o$pke wave function and the wave function deduced from Antisymmetrized Molecular Dynamics calculations. The remarkable agreement between calculated and measured cross-sections in both shape and magnitude validates the description of the $$^{10}$$Be ground-state as a rather compact nuclear molecule.

Journal Articles

Application of quasi-Monte Carlo and importance sampling to Monte Carlo-based fault tree quantification for seismic probabilistic risk assessment of nuclear power plants

Kubo, Kotaro; Tanaka, Yoichi; Hakuta, Yuto*; Arake, Daisuke*; Uchiyama, Tomoaki*; Muramatsu, Ken

Mechanical Engineering Journal (Internet), 10(4), p.23-00051_1 - 23-00051_17, 2023/08

The significance of probabilistic risk assessments (PRAs) of nuclear power plants against external events was re-recognized after the Fukushima Daiichi Nuclear Power Plant accident. Regarding the seismic PRA, handling correlated failures of systems, components, and structures (SSCs) is very important because this type of failure negatively affects the redundancy of accident mitigation systems. The Japan Atomic Energy Research Institute initially developed a fault tree quantification methodology named the direct quantification of fault tree using Monte Carlo simulation (DQFM) to handle SSCs' correlated failures in detail and realistically. This methodology allows quantifying the top event occurrence probability by considering correlated uncertainties related to seismic responses and capacities with Monte Carlo sampling. The usefulness of DQFM has already been demonstrated. However, improving its computational efficiency would allow risk analysts to perform several analyses. Therefore, we applied quasi-Monte Carlo and importance sampling to the DQFM calculation of simplified seismic PRA and examined their effects. Specifically, the conditional core damage probability of a hypothetical pressurized water reactor was analyzed with some assumptions. Applying the quasi-Monte Carlo sampling accelerates the convergence of results at intermediate and high ground motion levels by an order of magnitude over Monte Carlo sampling. The application of importance sampling allows us to obtain a statistically significant result at a low ground motion level, which cannot be obtained through Monte Carlo and quasi-Monte Carlo sampling. These results indicate that these applications provide a notable acceleration of computation and raise the potential for the practical use of DQFM in risk-informed decision-making.

Journal Articles

Neutron reflectometry analysis of condensed water layer formation at a solid interface of epoxy resins under high humidity

Liu, Y.*; Miyata, Noboru*; Miyazaki, Tsukasa*; Shundo, Atsuomi*; Kawaguchi, Daisuke*; Tanaka, Keiji*; Aoki, Hiroyuki

Langmuir, 39(29), p.10154 - 10162, 2023/06

 Times Cited Count:6 Percentile:67.88(Chemistry, Multidisciplinary)

Journal Articles

CFD-based analysis and experimental study on gas entrainment phenomenon due to free surface vortex

Song, K.*; Ito, Kei*; Ito, Daisuke*; Odaira, Naoya*; Saito, Yasushi*; Matsushita, Kentaro; Ezure, Toshiki; Tanaka, Masaaki

Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 10 Pages, 2023/05

Gas entrainment (GE) phenomena caused by a free surface vortex may cause the disturbance in core power of sodium-cooled fast reactor (SFR). For this reason, the entrained gas flow rate by the GE should be evaluated accurately for the practical safety design of SFRs. In this study, for the purpose of examining the applicability of CFD for the accurate evaluation of GE phenomena, a CFD is applied to the simulation of the free surface vortex and accompanied GE phenomena in a cylindrical vessel with a suction pipe, and the CFD results and the experimental data of the GE are compared. As a result, the CFD and experiments show similar two-phase flow pattern inside the suction pipe, and the shape of the gas core at the free surface is also very similar. Therefore, it is confirmed that the CFD can predict the GE phenomena triggered by a free surface vortex properly and accurately within the acceptable error range.

Journal Articles

Kinetics of the interfacial curing reaction for an epoxy-amine mixture

Yamaguchi, Ko*; Kawaguchi, Daisuke*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Yamamoto, Satoru*; Tanaka, Keiji*

Physical Chemistry Chemical Physics, 24(36), p.21578 - 21582, 2022/09

 Times Cited Count:11 Percentile:80.42(Chemistry, Physical)

Journal Articles

A Scoping study on the use of direct quantification of fault tree using Monte Carlo simulation in seismic probabilistic risk assessments

Kubo, Kotaro; Fujiwara, Keita*; Tanaka, Yoichi; Hakuta, Yuto*; Arake, Daisuke*; Uchiyama, Tomoaki*; Muramatsu, Ken*

Proceedings of 29th International Conference on Nuclear Engineering (ICONE 29) (Internet), 8 Pages, 2022/08

After the Fukushima Daiichi Nuclear Power Plant accident, the importance of conducting probabilistic risk assessments (PRAs) of external events, especially seismic activities and tsunamis, was recognized. The Japan Atomic Energy Agency has been developing a computational methodology for seismic PRA, called the direct quantification of fault tree using Monte Carlo simulation (DQFM). When appropriate correlation matrices are available for seismic responses and capacities of components, the DQFM makes it possible to consider the effect of correlated failures of components connected through AND and/or OR gates in fault trees, which is practically difficult when methods using analytical solutions or multidimensional numerical integrations are used to obtain minimal cut set probabilities. The usefulness of DQFM has already been demonstrated. Nevertheless, a reduction of the computational time of DQFM would allow the large number of analyses required in PRAs conducted by regulators and/or operators. We; therefore, performed scoping calculations using three different approaches, namely quasi-Monte Carlo sampling, importance sampling, and parallel computing, to improve calculation efficiency. Quasi-Monte Carlo sampling, importance sampling, and parallel computing were applied when calculating the conditional core damage probability of a simplified PRA model of a pressurized water reactor, using the DQFM method. The results indicated that the quasi-Monte Carlo sampling works well at assumed medium and high ground motion levels, importance sampling is suitable for assumed low ground motion level, and that parallel computing enables practical uncertainty and importance analysis. The combined implementation of these improvements in a PRA code is expected to provide a significant acceleration of computation and offers the prospect of practical use of DQFM in risk-informed decision-making.

Journal Articles

Evaluation of gas entrainment flow rate by free surface vortex

Torikawa, Tomoaki*; Odaira, Naoya*; Ito, Daisuke*; Ito, Kei*; Saito, Yasushi*; Matsushita, Kentaro; Ezure, Toshiki; Tanaka, Masaaki

Konsoryu, 36(1), p.63 - 69, 2022/03

On free surface of a sodium cooled fast reactor, gas entrainment can be caused by free surface vortices, which may result in disturbance in core power. It is important to develop an evaluation model to predict accurately entrained gas flow rate. In this study, entrained gas flow rate a simple gas entrainment experiment is conducted with focusing on effect of pressure difference between upper and lower tanks. Pressure difference between upper and lower tanks are controlled by changing gas pressure in lower tank. As a result, it is confirmed that the entrained gas flow rate increases with increasing pressure difference between upper and lower tanks. By visualization of swirling annular flow in suction pipe, it is also observed that pressure drop in suction pipe increases with increase in entrained gas flow rate, which implies that entrained gas flow rate can be predicted by evaluation model based on pressure drop in swirling annular flow region.

Journal Articles

Stochastic estimation of radionuclide composition in wastes generated at Fukushima Daiichi Nuclear Power Station using Bayesian inference

Sugiyama, Daisuke*; Nakabayashi, Ryo*; Tanaka, Shingo*; Koma, Yoshikazu; Takahatake, Yoko

Journal of Nuclear Science and Technology, 58(4), p.493 - 506, 2021/04

 Times Cited Count:2 Percentile:23.22(Nuclear Science & Technology)

Journal Articles

High temperature gas-cooled reactors

Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.

High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02

As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950$$^{circ}$$C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.

Journal Articles

Image-based view selection for shape comparison of mode water regions in virtual reality spaces

Yano, Midori; Ito, Takayuki*; Tanaka, Yusuke*; Matsuoka, Daisuke*; Araki, Fumiaki*; Czauderna, T.*; Stephens, K.*

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.201 - 208, 2020/10

Visual analysis plays an important role in understanding and evaluating the climate models, their variables, and their outputs because complex processes are required for the tuning of the climate models. Virtual Reality (VR) technologies are effective for 3D visualization and have been recently employed for visual analysis of more various scientific data. However, researchers may have some problematic situations while using VR space depending on user operations and target geometries. Here, we propose an image-based view selection method to solve these situations and understand differences in ocean states between simulations and observations based on shapes of mode water regions. This view selection takes evaluation criteria for shape comparison of mode water regions generated from simulations and observations into account. This paper introduces two example cases applying this view selection and discusses on a degree of shape matching of mode water regions of each case.

Journal Articles

Observation of morphological abnormalities in silkworm pupae after feeding $$^{137}$$CsCl-supplemented diet to evaluate the effects of low dose-rate exposure

Tanaka, Sota; Kinouchi, Tadatoshi*; Fujii, Tsuguru*; Imanaka, Tetsuji*; Takahashi, Tomoyuki*; Fukutani, Satoshi*; Maki, Daisuke*; Notomi, Akihiro*; Takahashi, Sentaro*

Scientific Reports (Internet), 10, p.16055_1 - 16055_7, 2020/09

 Times Cited Count:7 Percentile:47.30(Multidisciplinary Sciences)

Since the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, morphological abnormalities of the lepidopteran insects have been reported. However, it is unclear whether the abnormalities were caused directly by radiation because they did not study on absorbed dose and dose-effect relationship. In this study, we conducted an internal exposure experiment on silkworm using $$^{137}$$CsCl-supplemented artificial diet and estimated the absorbed dose to evaluate the morphological abnormalities in silkworm. The ratio of wing to whole body of pupae was compared between the $$^{137}$$CsCl-exposured and control groups and no significant differences were observed between the groups. This result suggest that morphological abnormalities in lepidopterans are unlikely due to direct radiation effects from $$^{137}$$Cs contamination after the FDNPP accident.

Journal Articles

Production of $$^{266}$$Bh in the $$^{248}$$Cm($$^{23}$$Na,5$$n$$)$$^{266}$$Bh reaction and its decay properties

Haba, Hiromitsu*; Fan, F.*; Kaji, Daiya*; Kasamatsu, Yoshitaka*; Kikunaga, Hidetoshi*; Komori, Yukiko*; Kondo, Narumi*; Kudo, Hisaaki*; Morimoto, Koji*; Morita, Kosuke*; et al.

Physical Review C, 102(2), p.024625_1 - 024625_12, 2020/08

 Times Cited Count:6 Percentile:52.67(Physics, Nuclear)

Journal Articles

Detailed structural study on the poly(vinyl alcohol) adsorption layers on a Si substrate with solvent vapor-induced swelling

Miyazaki, Tsukasa*; Miyata, Noboru*; Yoshida, Tessei*; Arima, Hiroshi*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; et al.

Langmuir, 36(13), p.3415 - 3424, 2020/04

 Times Cited Count:17 Percentile:60.83(Chemistry, Multidisciplinary)

Journal Articles

Elucidation of a heterogeneous layered structure in the thickness direction of poly(vinyl alcohol) films with solvent vapor-induced swelling

Miyazaki, Tsukasa*; Miyata, Noboru*; Asada, Mitsunori*; Tsumura, Yoshihiro*; Torikai, Naoya*; Aoki, Hiroyuki; Yamamoto, Katsuhiro*; Kanaya, Toshiji*; Kawaguchi, Daisuke*; Tanaka, Keiji*

Langmuir, 35(34), p.11099 - 11107, 2019/08

 Times Cited Count:25 Percentile:68.01(Chemistry, Multidisciplinary)

Journal Articles

Study on evaluation method for entrained gas flow rate by free surface vortex

Ito, Kei*; Ito, Daisuke*; Saito, Yasushi*; Ezure, Toshiki; Matsushita, Kentaro; Tanaka, Masaaki; Imai, Yasutomo*

Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.6632 - 6642, 2019/08

In this paper, a mechanistic model is proposed to calculate the entrained gas flow rate by a free surface vortex. The model contains the theoretical equation of transient gas core elongation and the empirical equation of critical gas core length for gas bubble detachment. Based on those two equations, the entrained gas flow rate is calculated as the portion of the gas core elongated beyond the critical gas core length per unit time. Then, the mechanistic model was applied to the calculation of the entrained gas flow rate in a simple water experiment. As a result, it is confirmed that the entrained gas flow rate grows rapidly when the liquid (water) flow rate, which determine the strength of a free surface vortex, exceeds a certain threshold value.

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