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Journal Articles

Development of wide range photon detection system for muonic X-ray spectroscopy

Mizuno, Rurie*; Niikura, Megumi*; Saito, Takeshi*; Matsuzaki, Teiichiro*; Sakurai, Hiroyoshi*; Amato, A.*; Asari, Shunsuke*; Biswas, S.*; Chiu, I.-H. ; Gianluca, J.*; et al.

Nuclear Instruments and Methods in Physics Research A, 1060, p.169029_1 - 169029_14, 2024/03

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:30 Percentile:96.87(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Analysis of the ozone reduction event over the southern tip of South America in November 2009

Akiyoshi, Hideharu*; Kadowaki, Masanao; Nakamura, Haruna*; Sugita, Takafumi*; Hirooka, Toshihiko*; Harada, Yayoi*; Mizuno, Akira*

Journal of Geophysical Research; Atmospheres, 123(22), p.12523 - 12542, 2018/11

AA2018-0443.pdf:12.61MB

 Times Cited Count:1 Percentile:2.95(Meteorology & Atmospheric Sciences)

A reduction of the total ozone over the southern tip of South America lasting 3 weeks occurred in November 2009. Analyses of the ERA-Interim reanalysis data and the total ozone observed by the Ozone Monitoring Instrument indicate that the total ozone reduction event was caused by a migration of the polar vortex toward the South American continent at the time of the vortex breakup. The vortex migration is associated with an enhanced wave flux from the troposphere at 120-150$$^{circ}$$W and 50-60$$^{circ}$$S to the west of the South American continent to the stratosphere over the southern part of the continent, which led to a large negative geopotential height anomaly in the lower stratosphere. In November, a blocking event was diagnosed from the 500-hPa geopotential height over the west of the South American continent. These results suggest a relation between the long-lasting reduction of the total ozone over the southern tip of South America and the blocking phenomenon in the troposphere of the Southern Hemisphere through wave propagation from the blocking region in 2009. Analysis of the total ozone anomaly for 50-60$$^{circ}$$S and 65-75$$^{circ}$$W over the southern tip of South America in November for 1979-2015 indicates that the negative ozone anomaly in November 2009 was one of the largest anomalies in this 37-year period and was associated with the large negative geopotential height anomaly in the lower stratosphere. Analyses of dynamical fields were also conducted for other years with large geopotential height anomalies.

Journal Articles

Determination of dissolved natural thorium and uranium in Horonobe and Mizunami Underground Research Laboratory groundwater and its thermodynamic analysis

Sasaki, Takayuki*; Kokami, Takayuki*; Kobayashi, Taishi*; Kirishima, Akira*; Murakami, Hiroaki; Amano, Yuki; Mizuno, Takashi; Iwatsuki, Teruki; Sasamoto, Hiroshi; Miyakawa, Kazuya

Journal of Nuclear Science and Technology, 54(3), p.373 - 381, 2017/03

Trace amounts of natural thorium and uranium in deep groundwater were investigated at two underground research laboratories situated at Horonobe and Mizunami, Japan. The groundwater was sampled from underground boreholes, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A decrease in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The result of the Th and U concentrations in groundwater after 10 kDa filtration was analyzed thermodynamically using existing hydrogeological and geochemical data such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and solid phase assumed. A crystalline solid phase made the solubility very low compared with that of the amorphous phase, and the solubility agreed well with the concentrations measured.

Journal Articles

Interaction of rare earth elements and components of the Horonobe deep groundwater

Kirishima, Akira*; Kuno, Atsushi*; Amamiya, Hiroki; Kubota, Takumi*; Kimuro, Shingo*; Amano, Yuki; Miyakawa, Kazuya; Iwatsuki, Teruki; Mizuno, Takashi; Sasaki, Takayuki*; et al.

Chemosphere, 168, p.798 - 806, 2017/02

 Times Cited Count:3 Percentile:10.31(Environmental Sciences)

For better understanding of the migration behavior of minor actinides (MA) in deep groundwater, the interaction of doped rare earth elements (REEs) and components in Horonobe deep groundwater was studied. Appx. 10 ppb of rare earth elements, i.e., Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm and Yb were doped to the sample groundwater collected from a packed sections in borehole drilled from 140 m depth experiment drift of Horonobe underground research laboratory (URL), Hokkaido, Japan. Then, that groundwater was sequentially filtrated by 0.2 micron pore filter, 10 kDa, 3 kDa and 1 kDa of nominal molecular weight limit (NMWL) ultrafilters by keeping inert condition. After that, the filtrate solutions were analyzed by ICP-MS to determine the concentrations of retained REEs at each filtration steps, while the used filters were analyzed by the neutron activation analysis (NAA) and TOF-SIMS element mapping to know the amount and chemical speciation of trapped fraction of the REEs on each filter. A remarkable relation between the retention ratios of REEs in the filtrate solutions and the ionic radius was observed, i.e., smaller rare earth element solves more in liquid phase under the Horonobe groundwater condition. NAA and TOF-SIMS analyses revealed that certain portions of REEs were trapped by 0.2 micron pore filters as rare earth phosphates which corresponded with the predicted predominant species by a chemical equilibrium calculation for the Horonobe groundwater condition, while small portions of colloidal REEs were trapped by 10 kDa and 3 kDa NMWL ultrafilters. The result suggested that phosphate anion plays an important role in the chemical behavior of REEs in saline (seawater based) groundwater, which could be referred for the prediction of migration behavior of trivalent actinide released from the repository of radioactive waste in far future.

Journal Articles

Preparation and evaluation of an astatine-211-labeled sigma receptor ligand for $$alpha$$ radionuclide therapy

Ogawa, Kazuma*; Mizuno, Yoshiaki*; Washiyama, Koshin*; Shiba, Kazuhiro*; Takahashi, Naruto*; Kozaka, Takashi*; Watanabe, Shigeki; Shinohara, Atsushi*; Odani, Akira*

Nuclear Medicine and Biology, 42(11), p.875 - 879, 2015/11

 Times Cited Count:22 Percentile:71.14(Radiology, Nuclear Medicine & Medical Imaging)

JAEA Reports

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2009

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; Mizuno, Takashi; et al.

JAEA-Review 2011-007, 145 Pages, 2011/03

JAEA-Review-2011-007.pdf:16.51MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU Project are planned in three overlapping phases; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document introduces the results of the research and development in fiscal year 2009, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site and the Shobasama Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration, etc. The goals of the Phase 2 are to develop and revise the models of the geological environment using the investigation results obtained during excavation and determine and assess changes in the geological environment in response to excavation, to evaluate the effectiveness of engineering techniques used for construction, maintenance and management of underground facilities, to establish detailed investigation plans of Phase 3.

JAEA Reports

Studies on planning and conducting for reducing water inflow due to underground construction in crystalline rock

Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Sugihara, Kozo; Takeuchi, Shinji; Hayano, Akira; Sato, Toshinori; Takeda, Shinichi; Ishii, Yoji; Ishida, Hideaki; et al.

JAEA-Technology 2010-026, 146 Pages, 2010/08

JAEA-Technology-2010-026.pdf:41.08MB
JAEA-Technology-2010-026-appendix(CD-ROM).zip:83.37MB

The Mizunami Underground Research Laboratory (MIU), one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the bedrock conditions, specifically the rock mass stability and hydrogeology. Therefore, borehole investigations were conducted before excavations started. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting was conducted before excavation of shafts and research tunnels. Grouting is the injection of material such as cement into a rock mass to stabilize and seal the rock. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting.

JAEA Reports

Mizunami Underground Research Laboratory Project Plan for fiscal year 2010

Takeuchi, Shinji; Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; et al.

JAEA-Review 2010-029, 28 Pages, 2010/08

JAEA-Review-2010-029.pdf:3.43MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU project is planned in three overlapping phases; Surface-based investigation phase (Phase1), Construction phase (Phase2) and Operation phase (Phase3). The project is currently under the construction phase, and the operation phase starts in 2010. This document introduces the research and development activities planned for 2010 fiscal year plan based on the MIU master plan updated in 2010, (1) Investigation plan, (2) Construction plan, (3) Research collaboration plan, etc.

JAEA Reports

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2008

Takeuchi, Shinji; Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; et al.

JAEA-Review 2010-014, 110 Pages, 2010/07

JAEA-Review-2010-014.pdf:27.34MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is developing a geoscientific research project named Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at MIU is planned to be carried out in three phases over a period of 20 years; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase. This document presents the following results of the research and development performed in fiscal year 2008, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site and the Shobasama Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration.

Journal Articles

Catalytic effect of Pt and Ag-loaded $$gamma$$-Al$$_{2}$$O$$_{3}$$ on the oxidation of xylene in air at low temperature under electron-beam irradiation

Hakoda, Teruyuki; Matsumoto, Kanae*; Mizuno, Akira*; Hirota, Koichi

International Journal of Plasma Environmental Science & Technology, 4(1), p.65 - 70, 2010/03

The catalytic effect of Pt/Al$$_{2}$$O$$_{3}$$ and Ag/Al$$_{2}$$O$$_{3}$$ on the oxidation of xylene in air was studied at a constant temperature of 373 K, when they were combined with electron-beam (EB)-induced non-thermal plasmas (NTPs). The presence of a catalyst bed was found to enhance the oxidation of the irradiation products of xylene. However, the degree of catalytic oxidation was different depending on the type of loaded metal and the position of the catalyst bed. Compared with a Al$$_{2}$$O$$_{3}$$ bed, a Pt/Al$$_{2}$$O$$_{3}$$ bed in the NTP space suppressed oxidation, while an Ag/Al$$_{2}$$O$$_{3}$$ bed downstream of the NTP space enhanced it. Under low temperature conditions, Pt/Al$$_{2}$$O$$_{3}$$ was not a suitable catalyst for the oxidation of organics in combination with the NTP process. On the other hand, the Ag/Al$$_{2}$$O$$_{3}$$ catalyst was a preferable catalyst for the NTP-induced oxidation of organics under such low temperature conditions.

JAEA Reports

Mizunami Underground Research Laboratory Project Plan for fiscal year 2009

Takeuchi, Shinji; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Amano, Kenji; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; et al.

JAEA-Review 2009-017, 29 Pages, 2009/08

JAEA-Review-2009-017.pdf:3.69MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is developing a geoscientific research project named the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at the MIU project is planned to be carried out in three phases over a period of 20 years; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document presents the following 2009 fiscal year plan based on the MIU Master Plan updated in 2002, (1) Investigation Plan, (2) Construction Plan, (3) Research Collaboration Plan, etc.

Journal Articles

Role of metals loaded on a TiO$$_{2}$$ Surface in the oxidation of xylene in air using an electron beam irradiation/catalytic process

Hakoda, Teruyuki; Matsumoto, Kanae*; Mizuno, Akira*; Hirota, Koichi

Applied Catalysis A; General, 357(2), p.244 - 249, 2009/04

 Times Cited Count:16 Percentile:38.2(Chemistry, Physical)

Catalytic oxidation of xylene in air was performed under electron beam (EB) irradiation using pure TiO$$_{2}$$ as well as TiO$$_{2}$$ loaded with Ag, Pt, Au, and Mn to clarify the role of loaded metal in the enhancement of oxidation of xylene and its irradiation byproducts to CO$$_{2}$$ in EB-induced non-thermal plasma. EB irradiation experiments were performed with the catalyst bed placed in both irradiated and non-irradiated spaces. The highest conversion percentage of decomposed xylene to CO$$_{2}$$ was obtained by irradiation/catalytic oxidation using an Ag/TiO$$_{2}$$ bed placed in a non-irradiated space. The greater enhancement of CO$$_{2}$$ production on an Ag/TiO$$_{2}$$ pellet surface compared to that on other metal-loaded TiO$$_{2}$$ pellet surfaces was due to the synergetic effect of strong adsorption of the byproducts on the Ag loaded on TiO$$_{2}$$ and production of active oxygen from decomposition of O$$_{3}$$ in the presence of Ag.

Journal Articles

Oxidation process of xylene in air using Ag/TiO$$_{2}$$ under electron beam irradiation

Hakoda, Teruyuki; Matsumoto, Kanae; Mizuno, Akira*; Narita, Tadashi*; Kojima, Takuji; Hirota, Koichi

IEEE Transactions on Industry Applications, 44(6), p.1950 - 1956, 2008/11

 Times Cited Count:3 Percentile:34.24(Engineering, Multidisciplinary)

Oxidation of xylene and its irradiation-induced organic byproducts in air using Ag-loaded TiO$$_{2}$$ (Ag/TiO$$_{2}$$) beds was studied under electron beam (EB) irradiation. The Ag/TiO$$_{2}$$ beds were placed in an irradiation or a non-irradiation space in order to identify the oxidation of xylene/its byproducts by EB irradiation, by catalytic process, and by a combination of the two. Placement of the Ag/TiO$$_{2}$$ bed to the irradiation space resulted in the suppression of xylene decomposition. On the other hand, production of CO$$_{2}$$ was observed in the gas phase of the irradiation space and on the surface of the Ag/TiO$$_{2}$$ pellets placed both in the irradiation and non-irradiation spaces. The concentration of CO$$_{2}$$ became higher when the layer was placed in the non-irradiation space. The production of CO$$_{2}$$ was enhanced by loading of Ag to the TiO$$_{2}$$ pellet surface. The highest concentration of CO$$_{2}$$ was obtained for Ag/TiO$$_{2}$$ with Ag contents greater than 5wt%.

Journal Articles

Oxidation of xylene and its irradiation byproducts using an electron-beam irradiating a $$gamma$$-Al$$_{2}$$O$$_{3}$$ bed

Hakoda, Teruyuki; Matsumoto, Kanae*; Mizuno, Akira*; Hirota, Koichi

Journal of Physics D; Applied Physics, 41(15), p.155202_1 - 155202_7, 2008/08

 Times Cited Count:3 Percentile:14.43(Physics, Applied)

The oxidation of xylene and its irradiation byproducts in air using a $$gamma$$-Al$$_{2}$$O$$_{3}$$ bed was studied under electron-beam irradiation to enhance the decomposition of volatile organic compounds in ventilation gases emitted from paint factories. The use of the $$gamma$$-Al$$_{2}$$O$$_{3}$$ bed enhanced the oxidation of the irradiation byproducts to CO$$_{2}$$. Furthermore, the oxidation of the byproducts was accelerated by the placement of the $$gamma$$-Al$$_{2}$$O$$_{3}$$ bed in an irradiation space, because of the interaction of primary electrons with the surface of $$gamma$$-Al$$_{2}$$O$$_{3}$$ pellets. This combined oxidation process enabled a reduction in the energy consumption for non-toxic CO$$_{2}$$ formation, and improved the selectivity of CO$$_{2}$$ production.

Journal Articles

Catalytic oxidation of xylene in air using TiO$$_{2}$$ under electron beam irradiation

Hakoda, Teruyuki; Matsumoto, Kanae; Mizuno, Akira*; Kojima, Takuji; Hirota, Koichi

Plasma Chemistry and Plasma Processing, 28(1), p.25 - 37, 2008/02

 Times Cited Count:22 Percentile:63.99(Engineering, Chemical)

The oxidation of xylene and its irradiation byproducts in air using TiO$$_{2}$$ was studied under electron beam (EB) irradiation for the purification of ventilation gases emitted from paint factories. EB irradiation experiments were performed mainly under two different conditions: a TiO$$_{2}$$ pellet layer was placed in an irradiation or non-irradiation space. The results revealed that xylene was decomposed and CO was formed in the gas phase of the irradiation space irrespective of the presence of the TiO$$_{2}$$ pellets, while CO$$_{2}$$ was produced in the gas phase of the irradiation space and on the surface of the TiO$$_{2}$$ pellets. The total CO$$_{2}$$ concentration increased when the pellet layer was in the non-irradiation space. On the other hand, the concentration of CO$$_{2}$$ produced on the surface of the TiO$$_{2}$$ pellets in the irradiation space was higher than that in a non-irradiation space.

JAEA Reports

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

JAEA Reports

Feasibility Study on the High Reliable Radiation Detection System using Normal Optical Fiber

Tsujimura, Norio; Yoshida, T.; Kawarabayashi, Jun*; Mizuno, Ryoji*; Naka, Ryotaro*; Uritani, Akira*; Watanabe, Kenichi*

JNC TY8400 2003-010, 46 Pages, 2003/03

JNC-TY8400-2003-010.pdf:1.36MB

The authors developed a radiation distribution monitor using a normal optical fiber. This monitor has long operation length (10m - 100m) and can obtain continuous radiation distribution.

Journal Articles

Decomposition mechanism for electron beam irradiation of vaporized trichloroethylene-air mixtures

Hakoda, Teruyuki; Hashimoto, Shoji; Fujiyama, Yuichi*; Mizuno, Akira*

Journal of Physical Chemistry A, 104(1), p.59 - 66, 2000/01

 Times Cited Count:32 Percentile:68.65(Chemistry, Physical)

no abstracts in English

Oral presentation

Oxidation process of xylene in air under electron beam irradiation with TiO$$_{2}$$ and Ag/TiO$$_{2}$$

Hakoda, Teruyuki; Matsumoto, Kanae; Mizuno, Akira*; Kojima, Takuji; Hirota, Koichi

no journal, , 

no abstracts in English

40 (Records 1-20 displayed on this page)