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Journal Articles

Development of numerical evaluation method for heat transportation with sodium mist in the cover gas region of sodium-cooled fast reactor

Hayakawa, Satoshi*; Hagiwara, Hiroyuki*; Imamura, Akira*; Onoda, Yuichi; Tanaka, Masaaki; Nakamura, Hironori*

Proceedings of 13th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS13) (Internet), 8 Pages, 2024/11

In a sodium-cooled fast reactor, a cover gas region filled with argon gas is located above the sodium pool in the main vessel to prevent the hot sodium from contacting the structures. This region involves heat transportation by natural convection of the cover gas, radiation among liquid surface and structures, and sodium phase change between mist and vapor. In this study, the numerical evaluation method has been developed with a commercial CFD code, Fluent, incorporating the sodium mist transport and growth models, and the radiation scattering model. Simulations of a laboratory scale test with a cylindrical cover gas region was carried out for the validation of the method and showed that the temperature distribution and sodium mist concentration in the cover gas region are in good agreements with the test results. A simulation of a pool-type sodium cooled fast reactor has also conducted and the basic aspect of physical phenomena taking place in the cover gas region were evaluated.

Journal Articles

Magnetic and transport properties of the pseudobrookite Al$$_{1-x}$$Ti$$_{2+x}$$O$$_{5}$$ single crystals

Takahama, Ryusei*; Arizono, Mitsutoshi*; Indo, Daigo*; Yoshinaga, Taisei*; Terakura, Chieko*; Takeshita, Nao*; Shirasaki, Takumi*; Noda, Masaaki*; Kuwahara, Hideki*; Kajimoto, Ryoichi; et al.

JPS Conference Proceedings (Internet), 38, p.011114_1 - 011114_6, 2023/05

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:64 Percentile:94.93(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Structural, magnetic, transport, and thermoelectric properties of the pseudobrookite AlTi$$_{2}$$O$$_{5}$$-Ti$$_{3}$$O$$_{5}$$ system

Takahama, Ryusei*; Ishii, Toi*; Indo, Daigo*; Arizono, Mitsutoshi*; Terakura, Chieko*; Tokura, Yoshinori*; Takeshita, Nao*; Noda, Masaaki*; Kuwahara, Hideki*; Saiki, Takuo*; et al.

Physical Review Materials (Internet), 4(7), p.074401_1 - 074401_11, 2020/07

 Times Cited Count:13 Percentile:40.99(Materials Science, Multidisciplinary)

Journal Articles

Schottky specific heat of the lightly Mn-substituted electron-doped SrTiO$$_3$$

Okuda, Tetsuji*; Kajimoto, Ryoichi; Noda, Masaaki*; Kuwahara, Hideki*

AIP Advances (Internet), 8(10), p.101339_1 - 101339_5, 2018/10

 Times Cited Count:1 Percentile:3.36(Nanoscience & Nanotechnology)

Journal Articles

Elastic and dynamical structural properties of La and Mn-doped SrTiO$$_{3}$$ studied by neutron scattering and their relation with thermal conductivities

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Murai, Naoki; Shamoto, Shinichi; Honda, Takashi*; Ikeda, Kazutaka*; Otomo, Toshiya*; Hata, Hiroto*; Eto, Takahiro*; Noda, Masaaki*; et al.

Scientific Reports (Internet), 8(1), p.9651_1 - 9651_8, 2018/06

 Times Cited Count:7 Percentile:45.20(Multidisciplinary Sciences)

Journal Articles

Neutron star cooling with various superfluid and superconducting states

Noda, Tsuneo*; Hashimoto, Masaaki*; Matsuo, Yasuhide*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*

JPS Conference Proceedings (Internet), 14, p.020805_1 - 020805_3, 2017/02

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

Journal Articles

Cooling of compact stars with color superconducting quark matter

Noda, Tsuneo*; Yasutake, Nobutoshi*; Hashimoto, Masaaki*; Maruyama, Toshiki; Tatsumi, Toshitaka*; Fujimoto, Masayuki*

Acta Astronomica Sinica, 56(Suppl.), p.52 - 54, 2015/11

We show a scenario for the cooling of compact stars considering the central source of Cassiopeia A (Cas A). The Cas A observation shows that the central source is a compact star with high effective temperature, and it is consistent with the cooling without exotic phases. The Cas A observation also gives the mass range of $$Mgeq 1.5 M_odot$$. It may conflict with the current cooling scenarios of compact stars that heavy stars show rapid cooling. We include the effect of the color superconducting (CSC) quark matter phase on the thermal evolution of compact stars. We assume the gap energy of CSC quark phase is large ($$Delta> 10$$ MeV), and we simulate the cooling of compact stars. We present cooling curves obtained from the evolutionary calculations of compact stars: while heavier stars cool slowly, and lighter ones indicate the opposite tendency.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2012) (Contract research)

Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Nobufumi*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.

JAEA-Technology 2014-019, 495 Pages, 2014/08

JAEA-Technology-2014-019.pdf:82.23MB

The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) research on engineering technology deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research is mainly aimed in this study, which is categorized in (a) development of design and construction planning technologies, (b) development of construction technologies, (c) development of countermeasure technologies, and (d) development of technologies for security. In this study, the researches on engineering technology are being conducted in these four categories by using data measured during construction as a part of the second phase of the MIU plan.

Journal Articles

Fabrication of enzyme-degradable and size-controlled protein nanowires using single particle nano-fabrication technique

Omichi, Masaaki*; Asano, Atsushi*; Tsukuda, Satoshi*; Takano, Katsuyoshi*; Sugimoto, Masaki; Saeki, Akinori*; Sakamaki, Daisuke*; Onoda, Akira*; Hayashi, Takashi*; Seki, Shu*

Nature Communications (Internet), 5, p.3718_1 - 3718_8, 2014/04

 Times Cited Count:36 Percentile:75.54(Multidisciplinary Sciences)

Protein nanowires exhibiting specific biological activities hold promise for interacting with living cells and controlling and predicting biological responses such as apoptosis, endocytosis and cell adhesion. Here we report the result of the interaction of a single high-energy charged particle with protein molecules. Degradation of the human serum albumin nanowires was examined using trypsin. The biotinylated human serum albumin nanowires bound avidin, demonstrating the high affinity of the nanowires. Human serum albumin-avidin hybrid nanowires were also fabricated from a solid state mixture and exhibited good mechanical strength. The biotinylated human serum albumin nanowires can be transformed into nanowires exhibiting a biological function such as avidin-biotinyl interactions and peroxidase activity. The present technique is a versatile platform for functionalizing the surface of any protein molecule with an extremely large surface area.

Journal Articles

Cooling of compact stars with color superconducting phase in quark-hadron mixed phase

Noda, Tsuneo*; Hashimoto, Masaaki*; Yasutake, Nobutoshi*; Maruyama, Toshiki; Tatsumi, Toshitaka*; Fujimoto, Masayuki*

Astrophysical Journal, 765(1), p.1_1 - 1_5, 2013/03

 Times Cited Count:37 Percentile:65.75(Astronomy & Astrophysics)

Journal Articles

Spiral spin structures and origin of the magnetoelectric coupling in YMn$$_2$$O$$_5$$

Kim, J.-H.*; Lee, S.-H.*; Park, S. I.*; Kenzelmann, M.*; Harris, A. B.*; Schefer, J.*; Chung, J.-H.*; Majkrzak, C. F.*; Takeda, Masayasu; Wakimoto, Shuichi; et al.

Physical Review B, 78(24), p.245115_1 - 245115_10, 2008/12

 Times Cited Count:46 Percentile:81.47(Materials Science, Multidisciplinary)

Journal Articles

Frustrated minority spins in GeNi$$_2$$O$$_4$$

Matsuda, Masaaki; Chung, J.-H.*; Park, S.*; Sato, Taku*; Matsuno, Kenichiro*; Katori, Hiroko*; Takagi, Hidenori*; Kakurai, Kazuhisa; Kamazawa, Kazuya*; Tsunoda, Yorihiko*; et al.

Europhysics Letters, 82(3), p.37006_1 - 37006_5, 2008/05

 Times Cited Count:24 Percentile:72.44(Physics, Multidisciplinary)

Recently, two consecutive phase transitions were observed, upon cooling, in an antiferromagnetic spinel GeNi$$_2$$O$$_4$$ at $$T_{N1}=12.1$$ K and $$T_{N2}=11.4$$ K, respectively. Using unpolarized and polarized elastic neutron scattering we show that the two transitions are due to the existence of frustrated minority spins in this compound. Upon cooling, at $$T_{N1}$$ the spins on the $$<$$111$$>$$ kagom$'e$ planes order ferromagnetically in the plane and antiferromagnetically between the planes (phase I), leaving the spins on the $$<$$111$$>$$ triangular planes that separate the kagom$'e$ planes frustrated and disordered. At the lower $$T_{N2}$$, the triangular spins also order in the $$<$$111$$>$$ plane (phase II). We also present a scenario involving exchange interactions that qualitatively explains the origin of the two purely magnetic phase transitions.

Journal Articles

A Long-term maintenance plan for the JT-60 power supply

Omori, Yoshikazu; Matsukawa, Makoto; Omori, Shunzo; Terakado, Tsunehisa; Okano, Jun; Noda, Masaaki*

NIFS-MEMO-36, p.358 - 361, 2002/06

no abstracts in English

Journal Articles

MCD study on materials without magnetic order

Miyahara, Tsuneaki*; Ishii, Hiroyoshi*; Takayama, Yasuhiro*; Hirose, Masaaki*; Maruyama, Kenichi*; Obu, Kenji*; Shinoda, Motoki*; Muro, Takayuki*; Saito, Yuji; Matsuda, Tatsuma*; et al.

Journal of the Physical Society of Japan, 70(10), p.2977 - 2981, 2001/10

 Times Cited Count:6 Percentile:41.50(Physics, Multidisciplinary)

no abstracts in English

JAEA Reports

Studies on Radiation Resistance of Fiber Reinforced Plastic Composites Featured by Easiness of Manufacturing-I Degradation Behavior under Electron Irradiation at Room Temperature

; Hagiwara, Miyuki; Kawanishi, Shuichi; Sasuga, Tsuneo; ; ; ; Sonoda, Katsumi*; ; ; et al.

JAERI-M 85-220, 26 Pages, 1986/01

JAERI-M-85-220.pdf:1.44MB

no abstracts in English

Oral presentation

Current status of a $$^{3}$$He spin filter development

Oku, Takayuki; Sakai, Kenji; Hiroi, Kosuke; Watanabe, Masao; Shinohara, Takenao; Aizawa, Kazuya; Kakurai, Kazuhisa*; Kira, Hiroshi*; Hayashida, Hirotoshi*; Kiriyama, Koji*; et al.

no journal, , 

We have been developing a $$^{3}$$He neutron spin filter for application at J-PARC MLF. The $$^{3}$$He neutron spin filter is available for neutrons in a wide energy range, and is also effective for a divergent neutron beam. Therefore, it is very useful in the neutron scattering experiment. So far, we have developed a compact laser optics with a volume holographic grating (VHG) elements, and have constructed an on-beam SEOP based $$^{3}$$He neutron spin filter. The polarization analysis tests were performed with the $$^{3}$$He neutron spin filter at several neutron beamlines for the sans, reflectivity and neutron imaging experiments. To extend the application range of the $$^{3}$$He neutron spin filter at J-PARC MLF, we plan to develop larger size cells, higher power laser for the SEOP, and prepare working area for the filter inside the MLF experimental hall.

Oral presentation

Development of design support tools (Automatic and optimized design of the expansion tank)

Yokoi, Shinobu*; Okafuji, Takashi*; Onoda, Yuichi; Tanaka, Masaaki

no journal, , 

no abstracts in English

Oral presentation

Evaluation of core cooling characteristics during natural circulation operation in a sodium-cooled pool-type fast reactor

Endo, Junji*; Imamura, Akira*; Imamura, Tomo*; Onoda, Yuichi; Hamase, Erina; Tanaka, Masaaki

no journal, , 

no abstracts in English

Oral presentation

Study of complex magnetic structures in frustrated magnets by means of polarized neutrons

Kakurai, Kazuhisa; Wakimoto, Shuichi; Matsuda, Masaaki*; Ishiwata, Shintaro*; Okuyama, Daisuke*; Taguchi, Yasujiro*; Tokura, Yoshiki*; Nishi, Masakazu*; Nakajima, Taro*; Mitsuda, Setsuo*; et al.

no journal, , 

26 (Records 1-20 displayed on this page)