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Yamamura, Sota*; Fujiwara, Kota*; Honda, Kota*; Yoshida, Hiroyuki; Horiguchi, Naoki; Kaneko, Akiko*; Abe, Yutaka*
Physics of Fluids, 34(8), p.082110_1 - 082110_13, 2022/08
Times Cited Count:2 Percentile:37.96(Mechanics)Liquid spreading and atomization due to jet impingement in liquid-liquid systems are considered to be crucial for understanding the cooling behavior of high-temperature molten material in a shallow water pool. This phenomenon takes place when a liquid jet enters a pool filled with other immiscible liquid. The jet spreads radially after impinging on the floor while forming a thin liquid film and atomizing droplets. In this paper, we explain the result to quantify the unsteady three-dimensional behavior of the spreading jet by the employment of 3D-LIF measurements and 3-dimensional reconstruction. Under high flow velocity conditions, the phenomena of hydraulic jump and atomization of the liquid film occurred along with the spreading. To evaluate the spreading behavior, a comparison of the jump radius position of the liquid-liquid system as the representative value was made with the one calculated by the existing theory of a gas-liquid system. As the result, the spreading of the liquid film in the liquid-liquid system was suppressed compared with that in the gas-liquid system. Furthermore, the PTV method was successfully used to measure the velocity boundary layer and velocity profile in the liquid film, which are important factors that affect the spreading mechanism of the liquid film. These results revealed that in liquid-liquid systems, shear stress at the liquid-liquid interface causes a decrease in the flow velocity and suppressed the development of the velocity boundary layer. Also, to evaluate the atomization behavior, the number and diameter distribution of the droplets were measured from the acquired 3-dimensional shape data of the jet. As the result, the number of droplets increased with the flow velocity. Based on these results, we concluded that the spreading of the liquid film is affected by such atomization behavior.
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:44 Percentile:97.1(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 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 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.
Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*
JAEA-Research 2017-001, 40 Pages, 2017/03
In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the CV-LRT in the MONJU. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, Testing time: 24 hours), there weren't significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (2.04C) required by the JEAC4203-2008.
Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*
JAEA-Research 2016-021, 32 Pages, 2017/02
In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the CV-LRT in the MONJU. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, Testing time: 24 hours), there weren't significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (2.04C) required by the JEAC4203-2008.
Matsuda, Makoto; Takeuchi, Suehiro; Tsukihashi, Yoshihiro; Hanashima, Susumu; Abe, Shinichi; Osa, Akihiko; Ishizaki, Nobuhiro; Tayama, Hidekazu; Nakanoya, Takamitsu; Kabumoto, Hiroshi; et al.
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan, p.275 - 277, 2006/00
no abstracts in English
Nakanoya, Takamitsu; Abe, Shinichi; Matsuda, Makoto; Nishio, Katsuhisa; Hanashima, Susumu; Ichikawa, Shinichi; Tsukihashi, Yoshihiro; Takeuchi, Suehiro; Ishiyama, Hironobu*; Jeong, S.-C.*; et al.
Dai-17-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.123 - 126, 2004/00
no abstracts in English
Nishitani, Takeo; Shikama, Tatsuo*; Sugie, Tatsuo; Kasai, Satoshi; Ishitsuka, Etsuo; Kawamura, Hiroshi; Kakuta, Tsunemi; Yagi, Toshiaki; Tanaka, Shigeru; Narui, Makoto*; et al.
JAERI-Research 2002-007, 149 Pages, 2002/03
no abstracts in English
; ; ; ; ; Araki, Kunio
JAERI-M 9388, 50 Pages, 1981/03
no abstracts in English
Osa, Akihiko; Abe, Shinichi; Asozu, Takuhiro; Hanashima, Susumu; Ishii, Tetsuro; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Kutsukake, Kenichi; Matsuda, Makoto; Nakamura, Masahiko; et al.
no journal, ,
At JAEA-tandem accelerator facility, we can produce radioactive nuclei by means of proton induced uranium fission, heavy ion fusion or transfer reaction. Since TRIAC was opened for use in 2005, we have provided RNBs of fission products and Li. For the production of Li, we chose C (Li, Li) neutron transfer reaction by Li primary beam and a 99% enriched C sintered disk target. The release time of Li ions from the C sintered target/ion source system was measured to be 3.2 s. We are developing the RNB of Li (T=178 ms) but the long release time caused a significant loss of the beam intensity. A boron nitride target which has fast release of Li is developed for Li beam with intensity of 10 pps after separation by JAEA-ISOL.
Chiba, Yusuke; Ichikawa, Shoichi; Ono, Shimpei; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Abe, Hisashi*; Kitano, Hiroshi*
no journal, ,
The lithium chloride-type dew point detector was used for reactor containment vessel the entire leak rate test (CV-LRT) in fast-breeder reactor Monju (Monju) which needs the maintenance every three months. But when the plant process is considered, it's desirable for the maintenance periods beyond 12 months. Thereupon the capacitance-type dew point detector made in VAISALA Corporation was nominated as the alternative lithium chloride-type dew point detector in Monju. The lithium chloride-type dew point detector, when it's adopted, for, to have to be satisfied a request of the regulations, it's necessary to estimate the performance of the lithium chloride-type dew point detector. In the condition of the CV-LRT, the dew point data were measured by the capacitance-type dew point detector and the lithium chloride-type dew point detector for 24 hours. These data were compared and the performance of the capacitance-type dew point detector was estimated. Furthermore, the dew point data of Monju under the atmosphere ware continuously measured by the capacitance-type dew point detector and the mirror surface-type dew point detector for 2 years. These data were compared and the performance of the capacitance-type dew point detector was estimated. As a result, the capacitance-type dew point detector was confirmed that had the instrument precision that JEAC4203-2008 required.
Hatori, Masakazu; Ichikawa, Shoichi; Chiba, Yusuke; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*; Ono, Fumiyasu
no journal, ,
In order to reduce the influence on a plant schedule of Monju by the maintenance of dew point hygrometers, JAEA Agency examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the containment vessel leak rate test in Monju. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, testing time/24 hours), there was no significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-precision-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, testing time: 24 months), it was confirmed that a capacitance type dew point hygrometer satisfied the instrument specification required by the CV-LRT. There are no other cases where atmosphere measurement has been carried out for a long time by existing measuring instruments.