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Journal Articles

Study on the predictive evaluation method for loads acting on roof and sidewall of cylindrical tank in nonlinear sloshing based on simplified equations

Ikesue, Shunichi*; Morita, Hideyuki*; Ishii, Hidekazu*; Sago, Hiromi*; Yokoi, Shinobu*; Yamamoto, Tomohiko

Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 8 Pages, 2021/07

In this paper, a new method is proposed for the nonlinear sloshing condition of a cylindrical tank, which can evaluate the vertical load acting on the roof and the horizontal load acting on the sidewall. This method is a combination of simplified equations for the liquid surface level and velocity proposed in the past study and the new pressure model modified from the existing model. A long calculation time as CFD analysis is not needed, because this method is consisted of simplified equations. The validity of this method was confirmed by comparing them with the CFD and the test. And future issues on the improvement of this method were clarified from the result.

Journal Articles

The Analysis of thermomechanical periodic motions of a drinking bird

Uechi, Schun*; Uechi, Hiroshi*; Nishimura, Akihiko

World Journal of Engineering and Technology, 7(4), p.559 - 571, 2019/11

A water drinking bird is discussed in terms of a thermomechanical model. A mathematical expression of motion derived from the thermomechanical model of a drinking bird and numerical solutions are explicitly shown, which is helpful in understanding physical meanings and fundamental difference between mechanical and thermomechanical periodic motion. The mathematical and physical differences between mechanical and thermomechanical periodic motion. The process of a drinking bird motion could be applied to energy harvesting technology by way of the current modeling.

Journal Articles

Bispectral analysis applied to coherent floating potential fluctuations obtained in the edge plasmas on JFT-2M

Nagashima, Yoshihiko*; Ito, Kimitaka*; Ito, Sanae*; Fujisawa, Akihide*; Hoshino, Katsumichi; Takase, Yuichi*; Yagi, Masatoshi*; Ejiri, Akira*; Ida, Katsumi*; Shinohara, Koji; et al.

Plasma Physics and Controlled Fusion, 48(4), p.S1 - S15, 2006/04

 Times Cited Count:33 Percentile:75.73(Physics, Fluids & Plasmas)

This paper presents the results of bispectral analysis of floating potential fluctuations in the edge region of ohmically heated plasmas in the JFT-2M tokamak. Inside of the outermost magnetic surface,coherent modes were observed around the frequency of geodesic acoustic mode which is a kind of the zonal flow. The squared bicoherence shows significant nonlinear couplings between the coherent fluctuations and the background fluctuations (which are likely to contain drift wave turbulent fluctuations). The experimental results that the total bicoherence is proportional to the squared amplitude of the coherent fluctuation, and that the biphase of the coherent modes localizes around a constant value $$pi$$, are consistent with the theoretical prediction on the drift wave - zonal flow systems based on the Hasegawa-Mima model.

Journal Articles

Observation of nonlinear coupling between small-poloidal wave-number potential fluctuations and turbulent potential fluctuations in Ohmically heated plasmas in the JFT-2M tokamak

Nagashima, Yoshihiko*; Hoshino, Katsumichi; Ejiri, Akira*; Shinohara, Koji; Takase, Yuichi*; Tsuzuki, Kazuhiro; Uehara, Kazuya; Kawashima, Hisato; Ogawa, Hiroaki; Ido, Takeshi*; et al.

Physical Review Letters, 95(9), p.095002_1 - 095002_4, 2005/08

 Times Cited Count:97 Percentile:92.95(Physics, Multidisciplinary)

By a reciprocating electrostatic probe, two types of low frequency coherent electrostatic modes (about1kHz and 10-15kHz) are found,for the first time, in the edge region of ohmically heated plasmas in the JFT-2M tokamak. These modes exists in the last closed surface. The higher frequency mode has features of the geodesic acoustic mode (GAM), though the low frequency mode is not identified yet. A bispectral analysis revealed that significant nonlinear couplings (parametric modulation) between these coherent fluctuations and broadband background turbulent potential fluctuations occur. In the other words, the GAM and the back ground turbulence are modulated by the newly found low frequency electrostatic mode (further, the GAM modulates the background turbulence, also) for the first time. The newly found low frequency mode (frequency about 1kHz) is supposed to contribute to the turbulent diffusion nonlinearly.

Journal Articles

Evaluation of nonlinear effects in the 3-GeV rapid cycling synchrotron of J-PARC

Hotchi, Hideaki; Noda, Fumiaki*; Tani, Norio; Kishiro, Junichi*; Machida, Shinji*; Molodojentsev, A. Y.*

Proceedings of 2005 Particle Accelerator Conference (PAC '05) (CD-ROM), p.916 - 918, 2005/00

no abstracts in English

Journal Articles

Study of drift wave-zonal mode system based on global electromagnetic landau-fluid ITG simulation in toroidal plasmas

Miyato, Naoaki; Li, J. Q.*; Kishimoto, Yasuaki

IAEA-CN-116/TH/8-5Rb (CD-ROM), 8 Pages, 2004/11

Using a global Landau fluid code in toroidal geometry, an electromagnetic ion temperature gradient (ITG) driven turbulence-zonal mode system is investigated. Two different types of zonal flows, i.e. stationary zonal flows in a low $$q$$ (safety factor) region and oscillatory ones in a high $$q$$ region which are called geodesic acoustic modes (GAM), are found to be simultaneously excited in a torus. The stationary flows efficiently suppress turbulent transport, while the oscillatory ones weakly affect the turbulence due to their time varying nature. Therefore in the low $$q$$ region where the zonal flows are stationary, the zonal flows are dominant over the turbulence. On the other hand, the turbulence is still active in the high $$q$$ region where the zonal flows are oscillatory.

Journal Articles

Reactivity estimation using digital nonlinear H$$_{infty}$$ estimator for VHTRC experiment

Suzuki, Katsuo; Nabeshima, Kunihiko; Yamane, Tsuyoshi; Fujii, Yoshio*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.408 - 417, 2003/12

On-line and real-time estimation of time-varying reactivity in a nuclear reactor is necessary for early detection of reactivity anomaly and safe operation. Using a digital nonlinear H$$infty$$ estimator, an experiment of real-time dynamic reactivity estimation was carried out in the VHTRC of JAERI. Some technical issues of the experiment are described, such as reactivity insertion, data sampling frequency, anti-aliasing filter, experimental circuit and digitalizing nonlinear H$$infty$$ reactivity estimator, and so on. Then, we discussed the experimental results obtained by the digital nonlinear H$$infty$$ estimator with sampled data of the nuclear instrumentation signal for the power responses under various reactivity insertions. Good performances of estimated reactivity were observed, with almost no delay to the true reactivity and sufficient accuracy between 0.05cent and 0.1cent. From the results of the experiment, it is concluded that the digital nonlinear H$$infty$$ reactivity estimator can be applied as on-line real-time reactivity meter for actual nuclear plants.

Journal Articles

Second harmonic generation in CdTe crystal and Te by free electron laser

Yamauchi, Toshihiko; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji

Technical Digest on 4th Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim 2001), p.I_426 - I_427, 2001/00

The second harmonic generation (SHG) signal converted from the 22 microns input wavelength of free electron laser (FEL) is observed using a non-birefringent CdTe crystal and a birefringent Te crystal. The conversion efficiency of SHG is obtained to be 2.2 x 10$$^{-2}$$ % (7.3 x 10$$^{-5}$$ %/(MW cm$$^{-2}$$)) in CdTe crystal and 0.4 % in Te crystal experimentally. The experimental -phase-matching angle of Te crystal is 9.62$$^{o}$$.

Journal Articles

Ideal/resistive modes analysis in reversed shear configuration plasmas

; Ishii, Yasutomo; ; Tokuda, Shinji; Ozeki, Takahisa; S.Hudson*; Kishimoto, Yasuaki

Chinese Physics Letters, 362, p.83 - 84, 1999/09

no abstracts in English

Journal Articles

A Particle-fluid hybrid simulation model based on nonlinear gyrokinetics

Tokuda, Shinji; Naito, Hiroshi*; W.W.Lee*

Purazuma, Kaku Yugo Gakkai-Shi, 74(1), p.44 - 53, 1998/01

no abstracts in English

Journal Articles

Numerical EXperiment of Tokamak project

Tokuda, Shinji

Purazuma, Kaku Yugo Gakkai-Shi, 72(9), p.916 - 919, 1996/09

no abstracts in English

Journal Articles

Estimation of dynamic reactivity using an H$$_{infty}$$ optimal filter with a nonlinear term

Suzuki, Katsuo;

Nuclear Technology, 113, p.145 - 154, 1996/02

 Times Cited Count:4 Percentile:40.53(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Importance measures in global sensitivity analysis of nonlinear models

Homma, Toshimitsu; A.Saltelli*

Reliab. Eng. Syst. Saf., 52, p.1 - 17, 1996/00

 Times Cited Count:1048 Percentile:100(Engineering, Industrial)

no abstracts in English

Journal Articles

Global sensitivity analysis of nonlinear models,Importance measures and Sobol' sensitivity indices

Homma, Toshimitsu; A.Saltelli*

EUR-16052, 0, 39 Pages, 1994/00

no abstracts in English

Journal Articles

Application of H$$_{infty}$$ control theory to power control of a nonlinear reactor model

Suzuki, Katsuo; Shimazaki, Junya; Shinohara, Yoshikuni

Nuclear Science and Engineering, 115, p.142 - 151, 1993/00

 Times Cited Count:21 Percentile:86.57(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Experiment and analysis on elastic deformation properties of graphite and carbon materials for HTTR core components

; Minato, Kazuo; Eto, Motokuni; Oku, Tatsuo*; *

JAERI-M 92-085, 28 Pages, 1992/06

JAERI-M-92-085.pdf:0.8MB

no abstracts in English

Journal Articles

Nonlinear dynamics of reactor with time delay in automatic control system and temperature effect

*; Hayashi, Koji; Shinohara, Yoshikuni

Journal of Nuclear Science and Technology, 29(6), p.530 - 546, 1992/06

no abstracts in English

JAEA Reports

A Study on the Aseismic Safety of the Experimental VHTR on the Dence Sandy Layer

; ; ; ; *; *; *; *

JAERI-M 86-166, 237 Pages, 1986/12

JAERI-M-86-166.pdf:6.49MB

no abstracts in English

JAEA Reports

Vectorization of the Nonlinear Heat Conduction Analysis Code HEATING6

; ; *; *; *

JAERI-M 85-153, 47 Pages, 1985/10

JAERI-M-85-153.pdf:1.14MB

no abstracts in English

Journal Articles

45 (Records 1-20 displayed on this page)