JOPSS - Search Results

Journal Articles

Cavitation damage prediction in mercury target for pulsed spallation neutron source using Monte Carlo simulation

Wakui, Takashi; Takagishi, Yoichi*; Futakawa, Masatoshi

Materials, 16(17), p.5830_1 - 5830_16, 2023/09

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

Cavitation damage on the mercury target vessel is induced by proton beam injection in mercury. The prediction method of the cavitation damage using Monte Carlo simulations was proposed taking into account of the uncertainties of the position of cavitation bubbles and impact pressure distributions. The distribution of impact pressure attributed to individual cavitation bubble collapsing was assumed to be the Gaussian distribution, and the probability distribution of the maximum value of impact pressures was assumed to be three kinds of distributions; the delta function, the Gaussian and Weibull distributions. Two parameters were estimated using Bayesian optimization by comparing the distribution of the cavitation damage obtained from experiment with that of accumulated plastic strain obtained from the simulation. It was found that the results obtained using the Weibull distribution reproduced the actual cavitation erosion phenomenon better than the other results.

Journal Articles

Insight on the mechanical properties of hierarchical porous calcium-silicate-hydrate pastes according to the Ca/Si molar ratio using synchrotron X-ray scattering and nanoindentation test

Im, S.*; Jee, H.*; Suh, H.*; Kanematsu, Manabu*; Morooka, Satoshi; Choe, H.*; Nishio, Yuhei*; Machida, Akihiko*; Kim, J.*; Lim, S.*; et al.

Construction and Building Materials, 365, p.130034_1 - 130034_18, 2023/02

https://doi.org/10.1016/j.conbuildmat.2022.130034

Times Cited Count：6 Percentile：70.19(Construction & Building Technology)

Journal Articles

Coherent eddies transporting passive scalars through the plant canopy revealed by Large-Eddy simulations using the lattice Boltzmann method

Watanabe, Tsutomu*; Takagi, Marie*; Shimoyama, Ko*; Kawashima, Masayuki*; Onodera, Naoyuki; Inagaki, Atsushi*

Boundary-Layer Meteorology, 181(1), p.39 - 71, 2021/10

https://doi.org/10.1007/s10546-021-00633-1

Times Cited Count：6 Percentile：47.35(Meteorology & Atmospheric Sciences)

A double-distribution-function lattice Boltzmann model for large-eddy simulations of a passive scalar field is described within and above a plant canopy. For a top-down scalar, for which the plant canopy serves as a distributed sink, the flux of the scalar near the canopy top are predominantly determined by sweep motions originating far above the canopy. By contrast, scalar ejection events are induced by coherent eddies generated near the canopy top. In this paper, the generation of such eddies is triggered by the downward approach of massive sweep motions to existing wide regions of weak ejective motions from inside to above the canopy.

Journal Articles

Monte Carlo criticality analysis under material distribution uncertainty

Ueki, Taro

Journal of Nuclear Science and Technology, 54(3), p.267 - 279, 2017/03

https://doi.org/10.1080/00223131.2016.1260066

Times Cited Count：8 Percentile：61.27(Nuclear Science & Technology)

Analysis framework under material distribution uncertainty is investigated for the Monte Carlo (MC) criticality calculation of continuously mixed media formed via molten core concrete interaction. Deterministic trigonometric functions and randomized Weierstrass functions are utilized to represent the spatially continuous variation. Numerical results indicate that the effective multiplication factor (k $_{rm eff}$ ) under random spatial variation can depart significantly from the k $_{rm eff}$ of a reference uniform medium. It is also shown that the deterministic modeling provides an upper-bound measure for extreme results from random realizations.

JAEA Reports

Water jet intrusion into hot melt concomitant with direct-contact boiling of water

Shibamoto, Yasuteru

JAERI-Research 2005-016, 127 Pages, 2005/08

JAERI-Research-2005-016.pdf:4.54MB

no abstracts in English

Journal Articles

Problem Solving Environment for supporting large-sclae simulation

Ueshima, Yutaka

PSE Book, p.69 - 82, 2005/03

no abstracts in English

Journal Articles

Accurate basis set by the CIP method for the solutions of the schrdinger equation

Utsumi, Takayuki*; Yabe, Takashi*; Koga, J. K.; Aoki, Takayuki*; Sekine, Masatoshi*

Computer Physics Communications, 157(2), p.121 - 138, 2004/02

https://doi.org/10.1016/S0010-4655(03)00496-X

Times Cited Count：13 Percentile：51.51(Computer Science, Interdisciplinary Applications)

no abstracts in English

Journal Articles

Formation of a charge-exchange target for fast ions in the plasma of large-scale toroidal devices under NBI conditions

Mironov, M. I.*; Khudoleev, A. V.*; Kusama, Yoshinori

Plasma Physics Reports, 30(2), p.164 - 168, 2004/02

https://doi.org/10.1134/1.1648943

Times Cited Count：0 Percentile：0.02(Physics, Fluids & Plasmas)

High-energy charge-exchange diagnostics can determine the distribution function of fast atoms produced via the neutralization of hydrogen ions by hydrogen-like impurity ions. Deriving the distribution function requires to know the composition and spatial distribution of the target ions in a plasma. A charge-exchange target forms as a result of the interaction between impurity nuclei and beam atoms. Depending on the arrangement of heating beams with respect to the diagnostics, it is necessary to calculate their trajectories. A model which takes into account elementary processes resulting in the ionization equilibrium of the ions of impurities in a specific tokamak configuration is proposed. The model is applied to the JT-60U plasma. Mechanisms for the formation of charge-exchange atomic flows are considered. The relative contributions of different heating injectors to the charge-exchange flow are estimated. Based on the calculated results, a method is proposed for local measurements of the ion distribution function with a stationary analyzer.

JAEA Reports