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246 results on '"Shimada, Kazuhiko"'

1. CASA, the Common Astronomy Software Applications for Radio Astronomy

Author

THE CASA TEAM, Bean, Ben, Bhatnagar, Sanjay, Castro, Sandra, Meyer, Jennifer Donovan, Emonts, Bjorn, Garcia, Enrique, Garwood, Robert, Golap, Kumar, Villalba, Justo Gonzalez, Harris, Pamela, Hayashi, Yohei, Hoskins, Josh, Hsieh, Mingyu, Jagannathan, Preshanth, Kawasaki, Wataru, Keimpema, Aard, Kettenis, Mark, Lopez, Jorge, Marvil, Joshua, Masters, Joseph, McNichols, Andrew, Mehringer, David, Miel, Renaud, Moellenbrock, George, Montesino, Federico, Nakazato, Takeshi, Ott, Juergen, Petry, Dirk, Pokorny, Martin, Raba, Ryan, Rau, Urvashi, Schiebel, Darrell, Schweighart, Neal, Sekhar, Srikrishna, Shimada, Kazuhiko, Small, Des, Steeb, Jan-Willem, Sugimoto, Kanako, Suoranta, Ville, Tsutsumi, Takahiro, van Bemmel, Ilse M., Verkouter, Marjolein, Wells, Akeem, Xiong, Wei, Szomoru, Arpad, Griffith, Morgan, Glendenning, Brian, and Kern, Jeff

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

CASA, the Common Astronomy Software Applications, is the primary data processing software for the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA), and is frequently used also for other radio telescopes. The CASA software can handle data from single-dish, aperture-synthesis, and Very Long Baseline Interferometery (VLBI) telescopes. One of its core functionalities is to support the calibration and imaging pipelines for ALMA, VLA, VLA Sky Survey (VLASS), and the Nobeyama 45m telescope. This paper presents a high-level overview of the basic structure of the CASA software, as well as procedures for calibrating and imaging astronomical radio data in CASA. CASA is being developed by an international consortium of scientists and software engineers based at the National Radio Astronomical Observatory (NRAO), the European Southern Observatory (ESO), the National Astronomical Observatory of Japan (NAOJ), and the Joint Institute for VLBI European Research Infrastructure Consortium (JIV-ERIC), under the guidance of NRAO., Comment: Accepted for publication in PASP (20 pages, 4 figures). Joint publication with CASA-VLBI paper

Published
2022
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25. Formation of highly Zn-enriched sulfide scale at a deep-sea artificial hydrothermal vent, Iheya-North Knoll, Okinawa Trough

Author

Nozaki, Tatsuo, Nagase, Toshiro, Torimoto, Junji, Takaya, Yutaro, Ishibashi, Jun-ichiro, Shimada, Kazuhiko, Watanabe, Masayuki, Masaki, Yuka, Iijima, Koichi, Kitada, Kazuya, Saitoh, Masafumi, Yokoyama, Takahiro, Akiyama, Keita, Sakurai, Noriaki, Saruhashi, Tomokazu, Kyo, Masanori, Kumagai, Hidenori, and Maeda, Lena

Subjects
Okinawa Trough, Seafloor massive sulfide (SMS) deposits, Hole C0014G, Deep-sea artificial hydrothermal vent, Hydrothermal scale, Iheya-North Knoll
Abstract

Artificial hydrothermal vents, created by boreholes that discharge hydrothermal fluids and useful for observing secular changes in mineral precipitates and the chemical compositions of hydrothermal fluids, are periodically cleaned of scale deposits. Here, we report petrographic and geochemical features of hydrothermal scale with a concentric structure and extreme enrichment in Zn, recovered as an intact plug from an artificial hydrothermal vent pipe in the Okinawa Trough. The scale consists of sphalerite with accessory galena and chalcopyrite, and minor cotunnite (PbCl2), barite, an unidentified Zn sulfate, and Bi-rich minerals. It comprises at least five concentric layers alternating between thin, reddish-brown porous layers composed of relatively Fe-rich sphalerite accompanied by galena and chalcopyrite, and coarse-grained, dark gray layers dominated by relatively Fe-poor sphalerite. Cotunnite occurs only in the innermost reddish-brown layer, and barite occurs only in the uppermost and innermost layers. The scale is composed of > 50 wt% Zn, several wt% Fe and Pb, and

Published
2020

32. Catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate

Author

Oyama, Keishi, Shimada, Kazuhiko, Ishibashi, Jun-ichiro, Sasaki, Keiko, Miki, Hajime, Okibe, Naoko, Oyama, Keishi, Shimada, Kazuhiko, Ishibashi, Jun-ichiro, Sasaki, Keiko, Miki, Hajime, and Okibe, Naoko

Abstract

The catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate (enargite 37.4%; pyrite 47.3%) was investigated by employing microbiological, electrochemical and kinetic studies. By using moderately thermophilic microorganisms at 45ºC, the final Cu dissolution was improved from 36% to 53% at 0.2% (w/v) activated carbon. An excess activated carbon addition showed an adverse effect. The enargite mineral itself favored higher solution redox potential (Eh) for solubilization. However, the dissolution of co-existing pyrite, which also favors high Eh, immediately hindered enargite dissolution through the passivation effect. The surface of activated carbon functioned as an electron mediator to couple RISCs oxidation and Fe<3+>+ reduction, so that elevation of the Eh level was controlled by offsetting microbial Fe<3+>+ regeneration. As long as the Eh level was suppressed at <700 mV, the dissolution of pyrite was largely avoided, enabling a steady and continuous dissolution of the enargite mineral through the surface chemical reaction model. When the Eh-control by activated carbon becomes no longer sustainable and the Eh hits 700 mV, rapid pyrite dissolution was initiated and the surface chemical reaction of enargite dissolution came to an end. Arsenic species dissolved from enargite was constantly immobilized with an efficiency of 75-90% as amorphous ferric arsenate. However, the sudden initiation of pyrite dissolution also triggered the re-solubilization of ferric arsenate. Therefore, the sustainable Eh-controlling effect was shown to be critical to enable longer Cu dissolution from enargite as well as stabilization of As precipitates.

Published
2021

33. Silver-catalyzed bioleaching of enargite concentrate using moderately thermophilic microorganisms

Author

Oyama, Keishi, Shimada, Kazuhiko, Ishibashi, Jun-ichiro, Miki, Hajime, Okibe, Naoko, Oyama, Keishi, Shimada, Kazuhiko, Ishibashi, Jun-ichiro, Miki, Hajime, and Okibe, Naoko

Abstract

Effect of silver (Ag) catalyst in bioleaching of enargite (Cu_3AsS_4) concentrate was studied using mixed cultures of moderately thermophilic acidophilic microorganisms at 45ºC. Addition of Ag_2S enabled selective Cu dissolution from enargite while suppressing pyrite oxidation: At the highest Ag_2S concentration of 0.04%, Cu recovery reached 96% while Fe dissolution was suppressed to reach only 29% by day 72. Overall results from thermodynamic calculation, liquid/solid analyses and kinetic study suggested that Ag-catalyzed bioleaching of enargite concentrate proceeds via formation of at least two types of secondary products (chalcocite, Cu_2S; trisilver arsenic sulfide, Ag_3AsS_4): Addition of Ag_2S as Ag catalyst thermodynamically and microbiologically contributed to lowering solution redox potentials during bioleaching, consequently satisfying Eox (Cu_2S) < E_h < E_c (Ag+) to enhance enargite dissolution via formation of chalcocite intermediate. Formation of trisilver arsenic sulfide and its intermediate layer (Cu,Ag)_3AsS_4 indicated that Cu ion in the enargite lattice is gradually substituted with Ag. Such secondary products did not impose a rate-limiting step, since the Ag-catalyzed bioleaching was shown to be controlled by a chemical surface reaction, rather than diffusion through product film which was the case in the absence of Ag_2S.

Published
2021

45. A Miocene impact ejecta layer in the pelagic Pacific Ocean

Author

Nozaki, Tatsuo, primary, Ohta, Junichiro, additional, Noguchi, Takaaki, additional, Sato, Honami, additional, Ishikawa, Akira, additional, Takaya, Yutaro, additional, Kimura, Jun-Ichi, additional, Chang, Qing, additional, Shimada, Kazuhiko, additional, Ishibashi, Jun-ichiro, additional, Yasukawa, Kazutaka, additional, Kimoto, Katsunori, additional, Iijima, Koichi, additional, and Kato, Yasuhiro, additional

Published
2019
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48. Thin anterior uterine wall with incomplete uterine rupture in a primigravida detected by palpation and ultrasound: a case report

Author

Usui Rie, Kuwata Tomoyuki, Shimada Kazuhiko, Matsubara Shigeki, and Suzuki Mitsuaki

Subjects
Medicine
Abstract

Abstract Introduction Uterine rupture is an obstetric complication associated with significant maternal and fetal morbidity and mortality. This disorder usually occurs with a scarred uterus, especially in a uterus with prior Cesarean section. Uterine sacculation or diverticulum may also lead to a thin uterine wall during pregnancy. Case presentation A 27-year-old Japanese primigravid woman was admitted to our hospital due to weak, irregular uterine contractions in her 38th week of gestation. She had no past history of uterine surgery or known diseases. A hard mass was palpable in her abdomen. An ultrasound revealed that the anterior uterine wall was thin and bulging, with a fetal minor part beneath it which corresponded to the palpated mass. A Cesarean section was performed which revealed a thin anterior uterine wall with incomplete uterine rupture. The woman and baby were healthy. Conclusions Although extremely rare, an unscarred primigravid uterus can undergo incomplete rupture even without discernable risk factors or labor pains. Abdominal palpation and ultrasound may be useful in detecting this condition.

Published
2011
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50. MOESM4 of Seafloor hydrothermal alteration affecting magnetic properties of abyssal basaltic rocks: insights from back-arc lavas of the Okinawa Trough

Author

Fujii, Masakazu, Sato, Hiroshi, Togawa, Eri, Shimada, Kazuhiko, and Jun-Ichiro Ishibashi

Abstract

Additional file 4: Figure S1. Backfield DC demagnetization curves of the studied lava samples; 6K#569R4-2, 6K#569R4-3, 6K#562R1, and 6K#569R4-1. The measurements were taken in limited field range to extract only remanent coercivity (Hcr). The 6K#569R4-3 sample display both fresh (solid line, top) and altered (broken line, bottom) specimens.

Published
2018
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