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Visualization and Measurement of Water Distribution in Through-Plane Direction of Polymer Electrolyte Fuel Cell during Start-Up by Using Neutron Radiography

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Journal of Flow Control, Measurement & Visualization 2015年第3期3卷 122-133页

作者： Hideki Murakawa Katsumi Sugimoto Nobuki Kitamura hitoshi asano Nobuyuki Takenaka Yasushi Saito Department of Mechanical Engineering Graduate School of Engineering Kobe University Kobe Japan Research Reactor Institute Kyoto University Osaka Japan

Water management in a polymer electrolyte fuel cell (PEFC) is a key topic for PEFC operation. A microporous layer (MPL) has been recently used to improve the water flooding in the gas diffusion layer (GDL) around the catalyst layer. However, the mechanisms of this MPL are not completely understood because of the difficulty of measuring the water distribution during operation. To clarify the water-accumulation phenomena with the MPL, visualization and measurement of the water distribution in the through-plane direction of a small fuel cell is carried out by using neutron radiography. The parallelism of the neutron flux is optimized by using a collimator to observe the transient change in the water distributions, and two-dimensional water distributions in the through-plane direction of the PEFC can be obtained every 60 s. The differences in the water accumulation processes in the GDL without and with the MPL under the lands and channels are compared. It is observed that the water accumulation in the GDL under the land is greater than that under the channel during the period of early PEFC operation. Water evacuation from the GDL to the channel mainly occurs around the land corners. Furthermore, one-dimensional water distributions are calculated from the visualized water distributions, and the results without and with the MPL in the cathode are compared. The water thickness in the through-plane direction attains its maximum value around the boundary between the catalyst layer and the GDL without the MPL, whereas it is attained between the MPL and the GDL with the MPL. The maximum water accumulation in the GDL under the land without the MPL is higher than that with the MPL.

关键词： PEFC Microporous Layer Water Distribution Neutron Radiography

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Recent Progress in JAXA Project of Boiling Two-Phase Flow Experiment onboard ISS

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Journal of Physical Science and Application 2012年第4期2卷 71-79页

作者： Kiyosumi Fujii Masato Komasaki Takashi Kurimoto Haruo Kawasaki Kenichiro Sawada Koichi Suzuki hitoshi asano Osamu Kawanami Ryoji Imai Yasuhisa Shinmoto Haruhiko Ohta ISS Science Project Office Japan Aerospace Exploration Agency(JAXA) Tsukuba Ibaraki Japan Thermal System Group Japan Aerospace Exploration Agency(JAXA) Tsukuba Ibaraki Japan Tokyo Univ. Sci. Yamaguchi Yamaguchi Japan Kobe University Kobe Hyogo Japan University of Hyogo Himeji Hyogo Japan IHI Corporation Yokohama Kanagawa Japan Dept. Aeronautics and Astronautics Kyushu University Fukuoka Japan

The amount of waste heat in a space facility became larger, because of increase in the space platform size and its power consumption. It requires development of high-performance space thermal management systems handling a large amount of waste. Boiling two-phase flow could become powerful means for this system because a boiling and condensation system is one of the most efficient modes of heat transfer due to phase change （liquid-vapor）. However, gravity effects on boiling two-phase flow phenomena and the corresponding heat transfer characteristics are not clear. Therefore, we prepare the experiments of boiling two-phase flow utilizing a long-term microgravity environment onboard a Japanese Experimental Module ＂KIBO＂ in the International Space Station （ISS） as one of the JAXA official projects. In this paper, recent progress of the preparation for the project is reported.

关键词： Boiling two-phase flow space science space technology ISS experiment microgravity.

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Degradation of 1,4-Dioxane Using Ozone Oxidation with UV Irradiation （Ozone/UV） Treatment

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Journal of Environmental Science and Engineering(A) 2012年第3期1卷 371-379页

作者： Masahiro asano Naoyuki Kishimoto hitoshi Shimada Yoshirou Ono Department of Environmental Solution Technology Faculty of Science and Technology Ryukoku University Shiga 5202194Japan Department of Design and Architecture Kyoto Institute of Technology Kyoto 6068585 Japan

A method for oxidative degradation of 1,4-dioxane （1,4-D） in waste water using a combination of ozone oxidation with UV irradiation （ozone/UV） treatment was investigated. The results showed that 1,4-D was degraded by ozone/UV treatment up to 90 min. The optimum concentration for the injected ozone gas was about 40 g·m^3 under a constant level of UV irradiation. Furthermore, solid phase extraction and GC-MS analysis showed no specific or reproducible peaks due to by-products of 1,4-D. It was therefore concluded that 1,4-D was completely degraded by ozone/UV treatment. In contrast, the amount of 1,4-D remaining decreased slowly in the presence of HCOf or CI. It was suggested that the degradation of 1,4-D, which results from .OH oxidation, was retarded by the presence of HCO3 or CI, which act as radical scavengers.

关键词： 1,4-dioxane (1,4-D) advanced oxidation processes (AOPs) ultraviolet (UV) ozone ozone oxidation with UVirradiation (ozone/UV) treatment radical scavenger.

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Rainfall and Runoff Observations in the Subtropical Forest of Okinawa Island, Japan

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Journal of Water Resource and Protection 2014年第6期6卷 625-634页

作者： Naoki Kabeya Akira Shimizu Takanori Shimizu hitoshi Ikuzawa Takuya Arakaki Hiroshi Furugen Yashuhiro Ohnuki Shiho asano Forestry and Forest Products Research Institute Tsukuba Japan Incorporated Okinawa Prefecture Environment Science Centre Urazoe Japan Kyushu Research Centre Forestry and Forest Products Research Institute Kumamoto Japan Okinawa Prefecture Forest Resource Research Centre Nago Japan

We set up two experimental catchments to provide an improved understanding of hydrological processes in a subtropical forested area in the northern part of Okinawa Island, Japan. We calculated runoff using water level data (recorded by a pressure-type water level gauge installed in a box culvert) and a discharge rating curve (derived from in situ observations). Water balance calculations for 2010 showed that the rainfall, runoff and evapotranspiration losses (= rainfall – runoff) were 3403.6 mm, 2285.7 mm and 1117.4 mm, respectively. This result was in agreement with previous results from other forested experimental catchments in this region. Direct runoff, as a proportion of event total rainfall, can be expressed by the empirical equation (Qdirect = 0.0048, Pevent 1.7971, R2 = 0.9599). When Pevent was 100 mm or less, the ratios of Qdirect to Pevent were less than 15% in general. When Pevent exceeded 100 mm, the ratios were 20% - 30%.

关键词： Direct Runoff Forested Watershed Okinawa Island Rainfall-Runoff Observation Sub-Tropical Forest Water Balance

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