Search

Your search keyword '"Hashizume, Hidetoshi"' showing total 401 results
Start Over Author "Hashizume, Hidetoshi"
401 results on '"Hashizume, Hidetoshi"'

107. Proposal of a TEM to TE01 mode converter for a microwave nondestructive inspection of axial flaws appearing on the inner surface of a pipe with an arbitrary diameter.

Author

Katagiri, Takuya, Sasaki, Kota, Song, Haicheng, Yusa, Noritaka, and Hashizume, Hidetoshi

Subjects
PIPE, STEEL pipe, COAXIAL cables, MICROWAVES, DIAMETER, NUMERICAL analysis, NONDESTRUCTIVE testing
Abstract

This study discusses the characteristics of a mode converter to generate microwaves in the TE01 mode for the long-range inspection of pipes. Numerical analysis was conducted to evaluate the effect of the pipe diameter and the number of coaxial cables inserted into the pipe on the efficiency of converting microwaves from the coaxial TEM mode to the circular TE01 mode. The results reveal that the most efficient frequency range for TE01 mode propagation strongly depends on the number of cables and pipe diameter. Subsequent experiments were performed using brass pipes with a length of 5 m and diameters of 39.0 and 74.0 mm. The results of these experiments are consistent with the results of the numerical analysis: the pipe with a diameter of 39.0 mm showed a clear signal from an axial slit 1.5 m away from the mode converter and the pipe with a diameter of 74.0 mm showed almost no difference between signals with or without the slit. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

116. Application of low-frequency eddy current testing to the inspection of a double-walled tank in a reprocessing plant.

Author

Tajima, Naoki, Yusa, Noritaka, and Hashizume, Hidetoshi

Subjects
EDDY current testing, REACTOR fuel reprocessing, THICKNESS measurement, AUSTENITIC stainless steel, IRON & steel plates
Abstract

This paper discusses the applicability of simple low-frequency eddy current testing to the detection of deeply embedded flaws. The study specifically considered a double tank in a reprocessing plant for extracting plutonium-uranium from spent nuclear fuels. The tank was modelled by two type 304 austenitic stainless steel plates situated with an air gap of 80 mm, and the change in the thickness of one of the plates was detected through the other plate and the air gap. Axisymmetric two-dimensional finite element simulations were conducted and found that a simple circular coil with a large diameter enabled to detect the thickness based on the magnetic flux density at the centre of the coil although the plates were as thick as 30 mm. The results of the numerical simulations were validated by experiments. [ABSTRACT FROM AUTHOR]

Published
2018
Full Text
View/download PDF

127. Numerical investigation of the ability of eddy current testing to size surface breaking cracks.

Author

Yusa, Noritaka and Hashizume, Hidetoshi

Subjects
*FINITE element method, *NUMERICAL analysis, *EDDY current testing, *ELECTRIC testing, *COMPUTER simulation
Abstract

This study attempts to estimate the limitations of eddy current testing for evaluating the depth of a crack with the aid of numerical simulations. Three-dimensional finite element simulations were conducted to obtain eddy current signals resulting from a crack in a plate made of Ni-based alloy. The simulations modelled the crack as a sufficiently long rectangular region with a constant width and depth. A uniform conductivity was given inside the modelled crack because actual cracks do not always behave as electrically insulating walls. The conductivity of the modelled crack was chosen on the basis of a recent study reporting how real cracks can be modelled from the viewpoint of electromagnetic non-destructive evaluation. This study considered three conventional eddy current probes: a pancake probe, a vertical pancake probe and a plus point probe. The results of the simulations reveal that lower frequency does not always enhance the evaluation of a deeper crack if the crack is conductive; moreover, the maximum depth of a stress corrosion crack that conventional eddy current testing can evaluate quantitatively should be limited to a few mm at most. In contrast, the simulations also demonstrate that the ability of eddy current testing to size a fatigue crack would not differ significantly from that to size an artificial slit. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

135. Performance of a Mechanical Bridge Joint for 30-kA-Class High-Temperature Superconducting Conductors

Author

Ito, Satoshi, primary, Kawai, Kenji, additional, Seino, Yutaro, additional, Ohinata, Tatsuya, additional, Tanno, Yusuke, additional, Yanagi, Nagato, additional, Terazaki, Yoshiro, additional, Natsume, Kyohei, additional, Hamaguchi, Shinji, additional, Noguchi, Hiroki, additional, Tamura, Hitoshi, additional, Mito, Toshiyuki, additional, Sagara, Akio, additional, and Hashizume, Hidetoshi, additional

Published
2014
Full Text
View/download PDF

139. Feasibility of HTS Magnet Option for Fusion Reactors

Author

YANAGI, Nagato, primary, ITO, Satoshi, additional, TERAZAKI, Yoshiro, additional, NATSUME, Kyohei, additional, TAMURA, Hitoshi, additional, HAMAGUCHI, Shinji, additional, MITO, Toshiyuki, additional, HASHIZUME, Hidetoshi, additional, MORIKAWA, Junji, additional, OGAWA, Yuichi, additional, IWAKUMA, Masataka, additional, and SAGARA, Akio, additional

Published
2014
Full Text
View/download PDF

143. 高速炉冷却系配管における流れの剥離現象に関する基礎研究; 高レイノルズ数領域におけるマルチエルボ内複雑流動構造の解明(先行基礎工学研究に関する平成20年度及び平成21年度共同研究報告書)

Author

江原 真司, Ebara, Shinji, 結城 和久, Yuki, Kazuhisa, 橋爪 秀利, Hashizume, Hidetoshi, 相澤 康介, Aizawa, Kosuke, 山野 秀将, Yamano, Hidemasa, 江原 真司, Ebara, Shinji, 結城 和久, Yuki, Kazuhisa, 橋爪 秀利, Hashizume, Hidetoshi, 相澤 康介, Aizawa, Kosuke, 山野 秀将, and Yamano, Hidemasa

Abstract

東北大学では、コールドレグ配管で発生する非定常流動メカニズム及び圧力変動特性を可視化試験及び圧力測定試験により明らかにし、さらにスケール効果を調べるため、異なる縮尺モデルにおいて流動試験を実施した。平成20年度では、1/15縮尺流動試験装置において2段エルボ内の可視化試験を実施した。また、1/7縮尺流動試験装置に1段ショートエルボを設置して装置の健全性を確認し、Re=320,000に対する可視化試験に着手した。平成21年度では、1/7縮尺流動試験装置を用いて1段エルボ及び2段立体接続エルボに関する可視化試験を実施し、詳細な流れ場を観測した。これら試験データから、エルボ内流れの複数エルボ効果を検討した。加えて、1/15及び1/7縮尺試験装置を用いて1段エルボに関する圧力変動計測試験を実施し、Re数を変化させたときの圧力変動特性を計測した。これらの配管スケールの異なる試験データより、圧力変動特性へのスケール効果の影響を検討した。原子力機構では、実機設計の成立性評価に向けて解析評価手法の開発を進めている。商用熱流動解析コードSTAR-CDを用いて1/7縮尺2段エルボ流動試験解析を実施し、可視化試験結果と流速分布の傾向はおおむね一致していることを示した。本研究より、単エルボ配管体系を対象に検証してきたURANS解析手法が2段エルボ体系に適用可能なことを確認した。, In Tohoku University, different scale model experiments were carried out in order to clarify unsteady flow fields and pressure fluctuation characteristics in the cold leg piping by means of visualization experiment and pressure measurement, respectively, and to investigate the scale effect. In JFY2008, the visualization experiment by PIV measurement for the 1/15 scale piping was carried out using a double elbow geometry. Besides, shakedown tests of the 1/7 scale model were conducted for the case of a single elbow. In JFY2009, visualization experiments for the 1/7 scale models with the single and a three-dimensionally connected double elbow geometries were carried out. From these obtained data, effects of the multiple elbows on the flow field were assessed. In addition, the pressure measurements for single elbow flows by using 1/15 and 1/7 scale models were performed. In JAEA, numerical analyses for the 1/7 scale double elbow experiments were performed using the commercial thermal-hydraulics code STAR-CD. The analyses showed that the calculated velocity distributions were in good agreement with the visualization experimental results. It was confirmed, from these analyses, that the URANS analysis method validated for the single elbow flow has applicability to the double elbow flow., 著者所属: 日本原子力研究開発機構(JAEA), JAEA-Research 2013-011

Published
2013

144. 高速炉冷却系配管における流れの剥離現象に関する基礎研究; 高レイノルズ数領域におけるマルチエルボ内複雑流動構造の解明(先行基礎工学研究に関する平成19年度共同研究報告書)

Author

結城 和久, Yuki, Kazuhisa, 橋爪 秀利, Hashizume, Hidetoshi, 中西 繁之, Nakanishi, Shigeyuki, 相澤 康介, Aizawa, Kosuke, 山野 秀将, Yamano, Hidemasa, 結城 和久, Yuki, Kazuhisa, 橋爪 秀利, Hashizume, Hidetoshi, 中西 繁之, Nakanishi, Shigeyuki, 相澤 康介, Aizawa, Kosuke, 山野 秀将, and Yamano, Hidemasa

Abstract

東北大学では、コールドレグ配管で発生する非定常流動メカニズムを明らかにし、さらにスケール効果を調べるため、実機の1/15縮尺試験と1/7縮尺試験が実施される。1/15縮尺試験については、平成19年度は2段エルボ体系で試験を行った。Re数は43000であり、エルボへの流入条件は完全発達乱流である。まず、全体的な流動構造として、第1エルボの内側で剥離が発生し、第2エルボでは1つの旋回流が形成されることが確認された。また、第1エルボ剥離域の終端部近傍で発生した非定常な流動が成長しながら下流方向に輸送され、第2エルボの管中央部に流入していることを指摘した。一方、1/7試験装置は作動流体が水であり、平成19年度は大流量条件を達成するための試験装置の設計と各コンポーネントの製作を実施した。原子力機構では、実機設計の成立性評価に向けて解析評価手法の開発を進めている。平成19年度は商用熱流動解析コードFLUENTを用いて1/15縮尺流動試験解析を実施し、可視化試験結果と流速分布の傾向はおおむね一致していることが示された。, At Tohoku University, 1/15 scale and 1/7 scale flow tests are being performed in order to clarify an unsteady flow structure in the cold leg piping and to investigate the scale effect. In FY2007, the 1/15 scale test was carried out using a double elbow geometry. It was confirmed that there existed a separation along the inner wall of the 1st elbow and a large swirling flow in the 2nd elbow. Furthermore, the unsteady flow formed in and/or behind the separation region was transported downstream and flows into the center area of the 2nd elbow. At JAEA, a numerical analytical evaluation method is being developed to evaluate the feasibility of the reactor design. In FY2007, numerical analyses for the 1/15 scale test were performed using the commercial thermal-hydraulics code FLUENT. The analyses showed that the trend of calculated velocity distributions was in good agreement with the visualization test results., 著者所属: 日本原子力研究開発機構(JAEA), JAEA-Research 2009-017

Published
2009

Catalog

Books, media, physical & digital resources
See catalog results