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Igarashi, Takahiro; Otani, Kyohei; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
Bosei Kanri, 66(4), p.141 - 145, 2022/04
Metal corrosion is a material deterioration phenomenon based on electrochemical reactions on an atomic scale. In this paper, various methods for acquiring physical properties on metal surfaces using first-principles calculations were described. As examples of applying first-principles calculation to metal corrosion, the effect of hydrogen adsorption on the metal surface on the potential change and the effect of cation atoms in the aqueous solution on the corrosion resistance of the metal were reported.
Kumazoe, Hiroyuki*; Igarashi, Yasuhiko*; Iesari, F.*; Shimizu, Ryota*; Komatsu, Yuya*; Hitosugi, Taro*; Matsumura, Daiju; Saito, Hiroyuki*; Iwamitsu, Kazunori*; Okajima, Toshihiko*; et al.
AIP Advances (Internet), 11(12), p.125013_1 - 125013_5, 2021/12
Times Cited Count:2 Percentile:7.86(Nanoscience & Nanotechnology)Igarashi, Takahiro; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
Tetsu To Hagane, 107(12), p.998 - 1003, 2021/12
Times Cited Count:0 Percentile:0(Metallurgy & Metallurgical Engineering)In order to clarify the effect of environmental factors on the amount of atmospheric corrosion of steel, novel model for predicting the reduction of atmospheric corrosion considering relative humidity and rain falls was developed. We conducted a one-year calculation simulation of atmospheric corrosion in Miyakojima City, Choshi City, and Tsukuba City using the developed model. Corrosion weight loss by the simulation could reproduce the measured value well. Corrosion weight loss at each point was greatly affected by the amount of flying sea salt, relative humidity, and rain falls.
Igarashi, Takahiro; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
Bosei Kanri, 65(10), p.365 - 370, 2021/10
We have developed a new atmospheric simulation model considering important environmental factors such as airborne sea salt, temperature, relative humidity, and rainfall. The developed model was verified by comparing predicted values by the simulation and measured data for the weight loss by atmospheric corrosion. In addition, atmospheric corrosion simulations under open and sheltered exposure condition were conducted, and it was confirmed that the air corrosion weight loss was strongly suppressed by the surface cleaning effect due to rainfall.
Igarashi, Takahiro; Otani, Kyohei; Kato, Chiaki; Sakairi, Masatoshi*; Togashi, Yusuke*; Baba, Kazuhiko*; Takagi, Shusaku*
ISIJ International, 61(4), p.1085 - 1090, 2021/04
Times Cited Count:1 Percentile:8.06(Metallurgy & Metallurgical Engineering)In order to clarify the effect of metal cations (Zn, Mg, Na) in aqueous solution on hydrogen permeation into iron, the amount of hydrogen permeation from iron surface was measured by electrochemical tests with a laser ablation. Moreover, in order to obtain the basic mechanism of hydrogen permeation with metal cation, first-principles calculations were used to acquire the adsorption potential of the metal cation and the electronic state around iron surface. By Zn in solution, anodic reaction on ablated surface by laser irradiation was suppressed. Also, by quantum analysis Zn atoms were chemically bonded stronger than Na and Mg atoms to iron surface. It was suggested that the dissolution reaction of iron was suppressed by the formation of the Zn layer, and that lead suppression of hydrogen permeation into iron.
Igarashi, Kai*; Onuki, Ryoji*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
Satou, Yukihiko; Sueki, Keisuke*; Sasa, Kimikazu*; Yoshikawa, Hideki; Nakama, Shigeo; Minowa, Haruka*; Abe, Yoshinari*; Nakai, Izumi*; Ono, Takahiro*; Adachi, Koji*; et al.
Geochemical Journal, 52(2), p.137 - 143, 2018/00
Times Cited Count:68 Percentile:97.15(Geochemistry & Geophysics)Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*
Bunseki Kagaku, 66(4), p.251 - 261, 2017/04
Times Cited Count:32 Percentile:79.03(Chemistry, Analytical)no abstracts in English
Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06
Times Cited Count:6 Percentile:45.25(Physics, Multidisciplinary)The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.
Fuchimukai, Junichi*; Yamaguchi, Hitoshi*; Meguro, Yoshihiro; Kubota, Toshio*; Igarashi, Shukuro*
Solvent Extraction Research and Development, Japan, 13, p.139 - 146, 2006/00
no abstracts in English
Igarashi, Kazuto*; Nemoto, Hirokazu*; Okano, Masanori; Yamada, Keiji; Sakai, Toshio
no journal, ,
no abstracts in English
Okano, Masanori; Igarashi, Kazuto*; Nemoto, Hirokazu*; Yamada, Keiji; Sakai, Toshio
no journal, ,
no abstracts in English
Okada, Takashi; Kawatsuma, Shinji; Fukushima, Mineo; Igarashi, Miyuki; Nakai, Koji; Mimura, Ryuji; Kanayama, Fumihiko
no journal, ,
Due to Tohoku Pacific Ocean earthquake and tsunami in 11 March in 2011, Tokyo Electric Power Co. Fukushima Daiichi Nuclear Power Station lost all power and has occurred accidents for failure of core cooling function. In Japan Atomic Energy Agency it was remodeled the nuclear disaster robot, was developed -ray visualization equipment and has been supporting the accident recovery. This paper is described the lessons learned from the supporting with the nuclear disaster robots and the -ray visualization equipment.
Okada, Takashi; Nakai, Koji; Igarashi, Miyuki; Kawatsuma, Shinji
no journal, ,
Japan Atomic Energy Agency developed a robotic control vehicle for supporting the accident recovery in the Fukushima Daiichi Nuclear Power Station. The developed robotic control vehicle can measure radiation using a cam and a robot with a radiation sensor. A heavily shielded operation box was built for reducing the exposure of radiation.
Igarashi, Kai*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
no journal, ,
In order to clarify the accumulation behavior on the core disruptive accident in sodium cooled fast reactors, an analysis for the experiment in which the low-melting point alloy drop into a shallow water pool was conducted by using SIMMER code. In this presentation, the validation result for the analysis geometry model conducted by the comparison of the calculation result and experimental value is presented.
Igarashi, Kai*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
no journal, ,
Simulation using SIMMER-III code was performed for an EAGLE-3 out-of-pile experiment whose objective was to clarify the fragmentation and cooling behavior of molten core material impinging onto a horizontal plate in sodium during core disruptive accidents of sodium-cooled fast reactors. Validation of the analytical model was confirmed by comparing analytical and experimental results.
Igarashi, Takahiro; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
no journal, ,
From the viewpoint of environmental and energy problems, research on atmospheric corrosion of steel materials is one of the important themes. In this study, we focused on the liquid film thickness, which is one of the environmental factors greatly related to the amount of corrosion, and constructed and simulated a corrosion prediction model using the amount of adsorbed salt and relative humidity as parameters. The developed model made it possible to express changes in corrosion rate due to changes in relative humidity day and night. In addition, there were times when the corrosion rate changed drastically during the day. Analysis of the simulation data suggested that this might be a change in the liquid film thickness due to the deliquescent of the contained salt.
Matsushita, Hatsuki*; Igarashi, Kai*; Isozaki, Kazuma*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
no journal, ,
no abstracts in English
Igarashi, Takahiro; Komatsu, Atsushi; Kato, Chiaki; Sakairi, Masatoshi*
no journal, ,
Large structures such as bridges and nuclear facilities in the sea shore area are exposed to a severe corrosive environment by airborne sea salt. From the viewpoint of ensuring facility safety and environmental and energy issues, it is one of the important themes to elucidate the mechanism of atmospheric corrosion of steel materials, which are the main materials of large structures. In the study, we modified existing model in which precipitation and humidity were considered as influential factors for atmospheric corrosion, and developed a novel model for predicting atmospheric corrosion loss with additional consideration of temperature. The developed model corrected the excessive prediction of corrosion amount by the existing model, and enabled more precise prediction of atmospheric corrosion weight loss.