Numerical verification for the effect of suppressing hydrogen embrittlement by Sn doping in the Al-Zn-Mg alloy

Ebihara, Kenichi; Fujihara, Hiro*; Shimizu, Kazuyuki*; Yamaguchi, Masatake; Toda, Hiroyuki*

International Journal of Hydrogen Energy, 136, p.751 - 756, 2025/06

https://doi.org/10.1016/j.ijhydene.2024.05.146

It has been experimentally reported that adding tin (Sn) to high-strength aluminum-zinc-magnesium (Al-Zn-Mg) alloys effectively suppresses hydrogen (H) embrittlement, which may be attributed to H absorption by the second-phase particles of Sn. To verify this fact, a simulation of H entry into the Sn phase in Al was performed using a model based on the reaction-diffusion equation that incorporates the solid solution energy of H evaluated by first-principles calculations. The results showed that the H solid solution site concentration of the second-phase particles must be at least five times higher than that of the Al phase for H absorption by the Sn second-phase particles to suppress H embrittlement. Therefore, the actual H embrittlement suppression effect of Sn second-phase particles is limited, and other factors may influence the suppression of H embrittlement in the experiment.

Novel approach to explore hydrogen trapping sites in aluminum; Integrating Muon spin relaxation with first-principles calculations

Shimizu, Kazuyuki*; Nishimura, Katsuhiko*; Matsuda, Kenji*; Nunomura, Norio*; Namiki, Takahiro*; Tsuchiya, Taiki*; Akamaru, Satoshi*; Lee, S.*; Tsuru, Tomohito; Higemoto, Wataru; et al.

International Journal of Hydrogen Energy, 95, p.292 - 299, 2024/12

https://doi.org/10.1016/j.ijhydene.2024.11.265

Zero-field muon spin relaxation experiments were conducted on Al-0.06%Mn, Al-0.06%Cr, Al-0.02%Fe, and Al-0.02%Ni alloys (at.%) across the temperature ranging from 5 to 300 K. The temperature-dependent variations of the dipole field widths () elucidated four distinct peaks for the prepared alloys. Atomic configurations of the muon trapping sites corresponding to the observed peaks below 200 K were meticulously characterized utilizing first-principles calculations for the trapping energies of hydrogen in proximity to a solute and solute-vacancy pair. This comprehensive analysis facilitated the establishment of a linear correlation between the muon peak temperature and the hydrogen trapping energy. However, significant deviations from this linear relationship were observed for the fourth peaks above 200 K in Al-Mn, Al-Cr, Al-Fe, and Al-Ni alloys. This discrepancy can be interpreted by considering the disparate distribution functions of muon and hydrogen within the tetrahedral site, wherein two of the four Al atoms are substituted by the solute element and vacancy (solute-vacancy pair).

Thermal analysis of the hydrogen release behavior of sodium hydride and kinetic analysis using master plot methods

Doi, Daisuke

International Journal of Hydrogen Energy, 91, p.1245 - 1252, 2024/11

https://doi.org/10.1016/j.ijhydene.2024.10.227

Analysis of ex-vessel debris coolability of boiling water reactors

Matsumoto, Toshinori; Hibiki, Takashi*; Maruyama, Yu

International Journal of Energy Research, 2024(1), p.9748588_1 - 9748588_18, 2024/08

https://doi.org/10.1155/2024/9748588

To evaluate the effectiveness of the wet cavity strategy, the authors developed a stochastic evaluation method that considers the uncertainties of the molten material conditions ejected from reactor pressure vessels. The first step was uncertainty analysis using the MELCOR code to obtain the melt condition. Five uncertain parameters related to the core degradation process were chosen. The input parameter sets were generated using Latin hypercube sampling. The second step was analyzing of the melt-behavior using the JASMINE code. The probabilistic distribution of parameters for the JASMINE analyses was determined from the MELCOR analysis results. The initial water depth was set to 0.5, 1.0, and 2.0 m. The debris height was compared with the criterion to judge its coolability. Consequently, the success probability of debris cooling was obtained through a sequence of calculations. The feasibility and technical difficulties in the MELCOR-JASMINE combined analysis were also discussed.

Opposing mixed convection heat transfer for turbulent single-phase flows

Motegi, Kosuke; Shibamoto, Yasuteru; Hibiki, Takashi*; Tsukamoto, Naofumi*; Kaneko, Junichi*

International Journal of Energy Research, 2024, p.6029412_1 - 6029412_22, 2024/01

https://doi.org/10.1155/2024/6029412

Convection, wherein forced and natural convections are prominent, is known as mixed convection. Specifically, when a forced convection flow is downward, this flow is called opposing flow. Several heat transfer correlations have been reported related to single-phase opposing flow; however, these correlations are based on experiments conducted in various channel geometries, working fluids, and thermal flow parameter ranges. Because the definition of nondimensional parameters and their validated range confirmed by experiments differ for each correlation reported in previous studies, establishing a guideline for deciding which correlation should be selected based on its range of applicability and extrapolation performance is important. This study reviewed the existing heat transfer correlations for turbulent opposing-flow mixed convection and the single-phase heat transfer correlations implemented in the thermal-hydraulic system codes. Furthermore, we evaluated the predictive performance of each correlation by comparing them with the experimental data obtained under various experimental conditions. The Jackson and Fewster, Churchill, and Swanson and Catton correlations (Int. J Heat Mass Transf., 1987) can accurately predict all the experimental data. The effect of the difference in the thermal boundary conditions, i.e., uniform heat flux and uniform wall temperature, on the turbulent mixed-convection heat transfer coefficient is not substantial. We confirmed that heat transfer correlations using the hydraulic-equivalent diameter as a characteristic length can be used for predictions regardless of channel-geometry differences. Furthermore, correlations described based on nondimensional dominant parameters can be used for predictions regardless of the differences in working fluids.

Hydrogen diffusion in cerium oxide thin films fabricated by pulsed laser deposition

Mao, W.*; Fukutani, Katsuyuki; 8 of others*

International Journal of Hydrogen Energy, 50(Part D), p.969 - 978, 2024/01

https://doi.org/10.1016/j.ijhydene.2023.08.264

The Investigations of the -wave states combining quark model and lattice QCD in the coupled channel framework

Yang, Z.*; Wang, G.-J.*; Wu, J.-J.*; Oka, Makoto; Zhu, S.-L.*

Journal of High Energy Physics (Internet), 2023(1), p.058_1 - 058_19, 2023/01

https://doi.org/10.1007/JHEP01(2023)058

Combining the quark model, the quark-pair-creation mechanism and interaction, we have investigated the near-threshold -wave states in the framework of the Hamiltonian effective field theory. With the heavy quark flavor symmetry, all the parameters are determined in the sector by fitting the lattice data. The masses of the bottom-strange partners of the and are predicted, which are well consistent with the lattice QCD simulation. The two -wave states are the mixtures of the bare core and component. Moreover, we find a crossing point between the energy levels with and without the interaction Hamiltonian in the finite volume spectrum in the case, which corresponds to a CDD (Castillejo-Dalitz-Dyson) zero in the -matrix of the scattering. This CDD zero will help deepen the insights of the near-threshold states and can be examined by future lattice calculation.

Artificial neural network-based path integral simulations of hydrogen isotope diffusion in palladium

Kimizuka, Hajime*; Thomsen, B.; Shiga, Motoyuki

Journal of Physics; Energy (Internet), 4(3), p.034004_1 - 034004_13, 2022/07

https://doi.org/10.1088/2515-7655/ac7e6b

Artificial neural network-based interatomic potential for a system of palladium and hydrogen was developed, and path integral molecular dynamics simulations were performed to study the quantum diffusion of hydrogen isotopes in palladium crystals. Diffusion coefficients of light and heavy hydrogen were calculated over a wide temperature range of 50-1500 K to clarify the difference in diffusion mechanisms at low and high temperatures.

Search for charged lepton flavor violating decays of

Patra, S.*; Tanida, Kiyoshi; Belle Collaboration*; 216 of others*

Journal of High Energy Physics (Internet), 2022(5), p.95_1 - 95_17, 2022/05

https://doi.org/10.1007/JHEP05(2022)095

First Measurement of the decay

Li, S. X.*; Tanida, Kiyoshi; Belle Collaboration*; 197 of others*

Journal of High Energy Physics (Internet), 2022(3), p.90_1 - 90_11, 2022/03

https://doi.org/10.1007/JHEP03(2022)090