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18 results on '"Sakuma, Hiraku"'

6. Application of Conductive Concrete as a Microbial Fuel Cell to Control H 2 S Emission for Mitigating Sewer Corrosion.

Author

Imai, Tsuyoshi, Vo, Huy Thanh, Fukushima, Masato, Suzuki, Tasuma, Sakuma, Hiraku, Hitomi, Takashi, and Hung, Yung-Tse

Subjects
SEWER pipes, TECHNOLOGICAL innovations, CONCRETE, SEWERAGE, HYDROGEN oxidation, MICROBIAL fuel cells, CHLORIDE ions
Abstract

Localized biogenic corrosion and extrication of annoying odors caused by hydrogen sulfide (H2S) have long been a big problem in the management of urban sewer systems. H2S emission control in sewers via chemically or biologically normal oxidation processes has also been investigated extensively and is costly. The objective of this work was to develop a new technology to mitigate the concentration of H2S in sewer pipes using conductive concrete. Experimental results after 66 days show that the concentration of hydrogen sulfide significantly decreased when conductive concrete was used as a microbial fuel cell. Both ordinary Portland cement and conductive concrete were utilized for the target experiment. Elemental sulfur was observed in the coating sludge of conductive concrete, whereas this trend was not observed for ordinary Portland cement. These observations demonstrate that conductive concrete provides an electron pathway from deposited sludge in the bottom of sewer pipes to oxygen dissolved in surface water electrons generated from hydrogen sulfide oxidation in an anaerobic environment via conductive concrete. Finally, regarding the mechanism responsible for hydrogen sulfide oxidation, chemical oxidation was the dominant process, and biological processes did not play a significant role. [ABSTRACT FROM AUTHOR]

Published
2022
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13. The Optical and Electrical Properties of Metal Photodoped Chalcogenide Glasses

Author

Shimizu, Isamu, Sakuma, Hiraku, Kokado, Hiroshi, and Inoue, Eiichi

Abstract

The optical and electrical properties of the metal photo-doped chalcogenide glasses were studied. The optical absorption of the chalcogenide glasses e.g., the As–S, As–S–Te, and As–S–Se systems) was increased by the photo-doping of such metals as Ag and Cu in the region of their absorption edges. The electrical conductivity of the glasses also increased with the photo-doping of the metals. The effective band gap obtained from the results of the temperature dependency of the electrical conductivity decreased with the increase in the amount of metal which was photo-doped in the glasses. The results obtained in this study suggest that the metals photo-doped in the chalcogenide glasses behaved as structural modifiers of the glasses, and that the state of density in the gap was increased by the metal photo-doping.

Published
1973
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