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242 results on '"Shimada, Masashi"'

15. Interaction of Hydrogen Isotopes with Radiation Damaged Tungsten

Author

Oya, Yasuhisa, Azuma, Keisuke, Togari, Akihiro, Zhou, Qilai, Hatano, Yuji, Shimada, Masashi, Kolasinski, Robert, Buchenauer, Dean, Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio S., Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, Luca, Dumitru, editor, Sirghi, Lucel, editor, and Costin, Claudiu, editor

Published
2018
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19. Report on the Second MPEX User Research Forum

Author

Rapp, Juergen, primary, Abrams, Tyler, additional, Allain, Jean Paul, additional, Baldwin, Matthew, additional, Maingi, Rajesh, additional, Parish, Chad, additional, Shimada, Masashi, additional, and Unterberg, Ezekial, additional

Published
2021
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21. The Nuclear Activity of the Galaxies in the Hickson Compact Groups

Author

Shimada, Masashi, Ohyama, Youichi, Nishiura, Shingo, Murayama, Takashi, and Taniguchi, Yoshiaki

Subjects
Astrophysics
Abstract

In order to investigate the nuclear activity of galaxies residing in compact groups of galaxies, we present results of our optical spectroscopic program made at Okayama Astrophysical Observatory. We have performed optical spectroscopy of 69 galaxies which belong to 31 Hickson Compact Groups (HCGs) of Galaxies. Among them, three galaxies have discordant redshifts. Further, spectral quality is too poor to classify other three galaxies. Therefore, we describe our results for the remaining 63 galaxies. Our main results are summarized below. (1) We have found in our sample; 28 AGN, 16 HII nuclei, and 19 normal galaxies which show no emission line. We used this HCG sample for statistical analyses. (2) Comparing the frequency distributions of activity types between the HCGs and the field galaxies whose data are taken from Ho, Filippenko, & Sargent (382 field galaxies), we find that the frequency of HII nuclei in the HCGs is significantly less than that in the field. However, this difference may be due to selection bias that our HCG sample contains more early-type galaxies than the field, because it is known that HII nuclei are rarer in early-type galaxies than in later ones. (3) Applying correction this morphological bias to the HCG sample, we find that there is no statistically significant difference in the frequency of occurrence of emission-line galaxies between the HCGs and the field. This implies that the dense galaxy environment in the HCGs does not affect triggering both the AGN activity and the nuclear starburst. We discuss some implications on the nuclear activity in the HCG galaxies., Comment: 33 pages (3 aasms4 LaTeX files), 5 figures (5 Postscript files: excluded Figure 1), Accepted for publication in The Astronomical Journal

Published
2000
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37. Relationship between post-vaccination symptoms of Moderna's SARS-CoV-2 vaccine and vaccine-induced anti-spike protein antibody titers in university sports club members

Author

Shiozaki, Yuya, primary, Takahashi, Koichiro, additional, Kaseda, Natsuko, additional, Kinoshita, Maki, additional, Shimomura, Daiki, additional, Shimada, Masashi, additional, Kamioka, Mikio, additional, Matuso, Shuji, additional, Kamiya, Nobuhiro, additional, and Yamanaka, Hideo, additional

Published
2022
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39. Comparison of S and N antibody titers before and after coronavirus vaccination between members of a COVID-19 outbreak sports club and a non-outbreak sports club

Author

Takahashi, Koichiro, primary, Kaseda, Natuko, additional, Shiozaki, Yuya, additional, Kinoshita, Maki, additional, Shimomura, Daiki, additional, Shimada, Masashi, additional, Matsuo, Shuji, additional, Kamioka, Mikio, additional, Kamiya, Norihiro, additional, and Yamanaka, Hideo, additional

Published
2022
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45. Influence of dynamic annealing of irradiation defects on the deuterium retention behaviors in tungsten irradiated with neutron

Author

Kobayashi, Makoto I, Shimada, Masashi, Taylor, Chase N., Buchenauer, Dean, Kolasinski, Robert, Koyanagi, Takaaki, NOBUTA, Yuji, Hatano, Yuji, Oya, Yasuhisa, Kobayashi, Makoto I, Shimada, Masashi, Taylor, Chase N., Buchenauer, Dean, Kolasinski, Robert, Koyanagi, Takaaki, NOBUTA, Yuji, Hatano, Yuji, and Oya, Yasuhisa

Abstract

Tungsten (W) samples were damaged by neutron and 6.4 MeV Fe-ion irradiation above 1000 K simulating the divertor operation temperature. Deuterium (D) retention properties were examined by decorating the damaged W with D and subsequent thermal desorption spectroscopy (TDS) measurements. Vacancy clusters were the major D trapping site in the W irradiated with Fe-ion at 873 K, although D retention by vacancy clusters decreased in the W irradiated with Fe-ion at 1173 K due to dynamic annealing. The D de-trapping activation energy from vacancy clusters was found to be 1.85 eV. D retention in neutron damage W was larger than that damaged by Fe-ion due to the uniform distribution of irradiation defects. The D desorption behaviors from neutron damaged W was simulated well by assuming the D de-trapping activation energy to be 1.52 eV., source:https://doi.org/10.1016/j.fusengdes.2019.03.003, identifier:0000-0003-0920-2154

Published
2021

48. Interpolation errors in rectangular and diamond characteristic grids

Author

Shimada, Masashi, Brown, James M.B., and Vardy, Alan E.

Subjects
Water hammer -- Evaluation, Transients (Dynamics) -- Evaluation, Water-pipes -- Design and construction, Water-pipes -- Mechanical properties, Hydraulic engineering -- Research, Engineering and manufacturing industries, Science and technology
Abstract

Analytical predictions of numerical errors in method of characteristics analyses using time-line interpolation in a rectangular grid are obtained for (1) both time-line and space-line interpolation and (2) both rectangular and diamond grids. Amplitude and frequency errors are investigated for each of these four cases using purpose-developed polynomial transfer matrices. Both semiinfinite and finite pipes are investigated. The time-line analysis permits reach back in time and the space-line analysis permits reach out in space. A common definition is adopted for the Courant number in the four cases and it is shown why stability can be achieved in reach- out analyses with Courant numbers greater than 1. In contrast with most work on error estimation, the predicted errors are obtained analytically, not numerically. This is made possible by restricting the analysis to special, but important, cases such as liquid-filled pipes in which the waves may be assumed to propagate at constant speed. Furthermore, the development is restricted to inviscid flows, thereby enabling interpolation errors to be assessed in the absence of complicating influences of discretization errors. In contrast with the latter, it is found that interpolation errors are more sensitive to the shape of numerical grids (i.e., Courant number and rectangular versus diamond grid) than to the size of the numerical time step. CE Database subject headings: Water hammers; Hydraulic transients; Errors; Grid systems; Pipe flow.

Published
2008

49. Time-line interpolation errors in pipe networks

Author

Shimada, Masashi, Brown, Jim, Leslie, Della, and Vardy, Alan

Subjects
Pipe lines -- Design and construction, Engineering and manufacturing industries, Science and technology
Abstract

An exact method of assessing numerical errors in analyses of unsteady flows in pipe networks is introduced. The assessment is valid for fixed-grid method of characteristics analyses using time-line interpolations. A pipe polynomial transfer matrix is developed and is analogous to transfer function matrices used in free oscillation theory. The influence of reachback is assessed by comparing exact numerical predictions using a polynomial transfer matrix with exact analytical predictions obtained using free oscillation theory. The investigation is part of a long-term project aimed at automating the selection of numerical grid sizes in unsteady flow analyses. The eventual goal is to enable users of unsteady flow software to prescribe required degrees of accuracy instead of specifying the numerical grid itself. This paper is only a first step toward the long-term aim, but it is a big step toward an intermediate objective of providing exact benchmarking data for the assessment of approximate methods of automatic grid selection. DOI: 10.1061/(ASCE)0733-9429(2006) 132:3(294) CE Database subject headings: Water hammers; Pipe networks; Errors; Resonance; Unsteady flow; Pipe flow.

Published
2006

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