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Horiguchi, Naoki; Yoshida, Hiroyuki; Kaneko, Akiko*; Abe, Yutaka*
Nihon Kikai Gakkai Kanto Shibu Dai-29-Ki Sokai, Koenkai Koen Rombunshu (Internet), 5 Pages, 2023/10
To elucidate the behavior of molten fuels as a liquid jet in a shallow pool, which is assumed in a core meltdown accident of an LWR, and develop the evaluation method, we investigated the behavior of the vortical liquid film of the simulated wall-impinging liquid jet using 3-dimensional interface shape data obtained by the experiment in a liquid-liquid system.
Horiguchi, Naoki; Yoshida, Hiroyuki; Kaneko, Akiko*; Abe, Yutaka*
Physics of Fluids, 35(7), p.073309_1 - 073309_17, 2023/07
Times Cited Count：0 Percentile：0.01(Mechanics)The atomization of a liquid jet in an immiscible liquid-liquid system is significant for the safety in the nuclear industry field. The Japan Atomic Energy Agency has developed an evaluation method of a melt fuel behavior as a liquid jet in an immiscible liquid-liquid system for subsequence using mechanistic numerical simulation and has investigated liquid jet behavior in a shallow pool through numerical simulations and experiments. The paper clarifies the atomization mechanism in the wall-impinging liquid jet. Herein, the atomization behavior in the wall-impinging liquid jet in a shallow pool in an immiscible liquid-liquid system was studied in terms of droplet formation and flow field using numerical simulation and the dispersed-phase tracking method. The results show that the droplet formation in the liquid film flow of the wall-impinging liquid jet had the three patterns, and we obtained the droplet properties immediately after droplet formation and developed the theoretical criterion regions using the dimensionless numbers for droplet formation. We characterized the patterns by comparing them with the regions and elucidated the droplet formation mechanisms depending on their sources. Moreover, we elucidated that the relationship between droplet formation as the local behaviors of the jet and atomization as the whole behavior.
Iwasaki, Sachio*; Jido, Daisuke*; Oka, Makoto; Suzuki, Kei
Physics Letters B, 820, p.136498_1 - 136498_6, 2021/09
Times Cited Count：2 Percentile：18.91(Astronomy & Astrophysics)We investigate time evolution of 
-wave charmonium populations under a time-dependent homogeneous magnetic field and evaluate survival probabilities of the low-lying charmonia to the goal of estimating the magnetic field strength at heavy-ion collisions. Our approach implements mixing between different spin eigenstates and transitions to radially excited states. We show that the survival probabilities can change even by an extremely short magnetic field. Furthermore, we find that the survival probabilities depend on the initial spin states. We propose the sum of the survival probabilities over spin partners as an observable insensitive to the initial states. We also find that the sum can be approximately given as a function of 
with a duration time 
and the maximum strength of the magnetic field 
.
Iwasaki, Sachio*; Oka, Makoto; Suzuki, Kei
European Physical Journal A, 57(7), p.222_1 - 222_14, 2021/07
Times Cited Count：17 Percentile：70.63(Physics, Nuclear)We review the properties of quarkonia under strong magnetic fields. The main phenomena are (i) mixing between different spin eigenstates, (ii) quark Landau levels and deformation of wave function, (iii) modification of 
potential, and (iv) the motional Stark effect. For theoretical approaches, we review (i) constituent quark models, (ii) effective Lagrangians, (iii) QCD sum rules, and (iv) holographic approaches.
Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori
JAEA-Technology 2021-002, 31 Pages, 2021/05
JAEA-Technology-2021-002.pdf:4.37MB
In the MOX fuel fabrication process, a dry recycle technology has been developed to effectively utilize dry recovered powder obtained by crushing out of specification MOX pellets. The particle size of the dry recovery powder is divided into three classes; coarse size (about 250 
m or less), medium size (about 100 m or less), and fine size (about 10 m or less) by the current crushers, and the effect of controlling the density of sintered pellets is obtained to a certain extent by adding the dry recovered powder to the raw powder. In this report, with the aim of more finely adjusting the particle size of the dry recovery powder, a buhrstone mill and a collision plate-type jet mill were selected as grinders that can adjust the dry recovered powder within a particle size range of 250 m or less, and the particle size adjustment test was conducted to pulverize the tungsten-carbide-cobalt (WC-Co) pellets as a simulated material for the MOX pellets. The buhrstone mill can control the particle size within a certain range by adjusting the grindstone clearance, but particles with a particle size of 250 m or more may be discharged. On the contrary, it is expected that the particle size of the collision plate-type jet mill can be controlled in the range of 250 m or less by adjusting the classification zone clearance. Therefore, the collision plate-type jet mill is more suitable for adjusting the particle size of the dry recovered powder than the buhrstone mill.
Suenaga, Daiki*; Araki, Yasufumi; Suzuki, Kei; Yasui, Shigehiro*
Physical Review D, 103(5), p.054041_1 - 054041_17, 2021/03
Times Cited Count：5 Percentile：45.23(Astronomy & Astrophysics)We investigate the influence of the Kondo effect, namely, the nonperturbative effect induced by heavy impurities, on the chiral separation effect (CSE) in quark matter. We employ a simple effective model incorporating the Kondo condensate made of a light quark and a heavy quark, and compute the response function of the axial current to the magnetic field in the static and dynamical limits. As a result, we find that the Kondo effect catalyzes the CSE in both of the limits, and in particular the CSE in the dynamical limit can be enhanced by a factor of approximately 3. Our findings clearly show that the presence of heavy impurities in quark matter can play an important role in the transport phenomena of light quarks induced by a magnetic field.
and 
mesons in U
U collisions at 
GeVAcharya, U.*; Hasegawa, Shoichi; Imai, Kenichi*; Nagamiya, Shoji*; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 397 of others*
Physical Review C, 102(6), p.064905_1 - 064905_13, 2020/12
Times Cited Count：5 Percentile：52.72(Physics, Nuclear)Gubler, P.; Sato, Daisuke*
JPS Conference Proceedings (Internet), 26, p.024023_1 - 024023_5, 2019/11
In this talk, I will introduce and review several exact sum rules of the vector channel spectral function at finite temperature, which we have derived in a recent paper. I will also discuss an explicit check of these sum rules in perturbation theory and possible application to the analysis of lattice QCD data.
Segawa, Tomoomi; Yamamoto, Kazuya; Makino, Takayoshi; Iso, Hidetoshi; Kawaguchi, Koichi; Ishii, Katsunori; Sato, Hisato; Fukasawa, Tomonori*; Fukui, Kunihiro*
Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.738 - 745, 2019/09
In the MOX fuel fabrication process, the dry grinding technology of mixed oxide pellets have been developed for the effective use of nuclear fuel materials. To develop a technology to control the particle size of dry recovered powder, the performance of the buhrstone mill and the collision plate type jet mill were studied using a simulated powder of particle size distribution about 500 m. We found that the particle size can be controlled at the range of about 250 m or less by both by adjusting the clearance between the grinding wheels of the buhrstone mill, and the clearance and elevation angle of the clarification zone of the collision plate type jet mill. And furthermore, the collision plate type jet mill is considered to be suitable for particle size control because the operating parameters of the classifier can be finely adjusted.
Adare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji*; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 666 of others*
Physical Review Letters, 123(2), p.022301_1 - 022301_10, 2019/07
Times Cited Count：30 Percentile：86.91(Physics, Multidisciplinary)Au collisions at 
GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji*; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 451 of others*
Physical Review C, 99(5), p.054903_1 - 054903_29, 2019/05
Times Cited Count：15 Percentile：83.07(Physics, Nuclear)
GeV proton-nucleus collisionsAidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 293 of others*
Physical Review C, 99(4), p.044912_1 - 044912_10, 2019/04
Times Cited Count：5 Percentile：47.88(Physics, Nuclear)Aidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 312 of others*
Nature Physics, 15(3), p.214 - 220, 2019/03
Times Cited Count：149 Percentile：99.03(Physics, Multidisciplinary)Maeyama, Shinya*; Watanabe, Tomohiko*; Idomura, Yasuhiro; Nakata, Motoki*; Nunami, Masanori*
Computer Physics Communications, 235, p.9 - 15, 2019/02
Times Cited Count：5 Percentile：46.27(Computer Science, Interdisciplinary Applications)We have implemented the Sugama collision operator in the gyrokinetic Vlasov simulation code, GKV, with an implicit time-integration scheme. The new method is versatile and independent of the details of the linearized collision operator, by means of an operator splitting, an implicit time integrator, and an iterative Krylov subspace solver. Numerical tests demonstrate stable computation over the time step size restricted by the collision term. An efficient implementation for parallel computation on distributed memory systems is realized by using the data transpose communication, which makes the iterative solver free from inter-node communications during iteration. Consequently, the present approach achieves enhancement of computational efficiency and reduction of computational time to solution simultaneously, and significantly accelerates the total performance of the application.
= 200 GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 317 of others*
Physical Review C, 99(2), p.024903_1 - 024903_16, 2019/02
Times Cited Count：11 Percentile：74.44(Physics, Nuclear) GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 448 of others*
Physical Review C, 98(5), p.054902_1 - 054902_11, 2018/11
Times Cited Count：14 Percentile：75.94(Physics, Nuclear) and mesons in Cu+Au collisions at =200 GeVAidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji*; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 397 of others*
Physical Review C, 98(5), p.054903_1 - 054903_11, 2018/11
Times Cited Count：11 Percentile：68.32(Physics, Nuclear)
+Al, +Au, 
+Au, and 
He+Au at = 200 GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 362 of others*
Physical Review Letters, 121(22), p.222301_1 - 222301_8, 2018/11
Times Cited Count：34 Percentile：86.03(Physics, Multidisciplinary)
hadrons in Au and collisions at GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 468 of others*
Physical Review C, 98(1), p.014912_1 - 014912_16, 2018/07
Times Cited Count：7 Percentile：53.6(Physics, Nuclear) + Au, + Au, and 
He + Au collisions at = 200 GeVAdare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 347 of others*
Physical Review C, 97, p.064904_1 - 064904_11, 2018/06
Times Cited Count：22 Percentile：86.47(Physics, Nuclear)