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Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
Times Cited Count：3 Percentile：15.82(Environmental Sciences)The dry and wet depositions of atmospheric ammonia (NH
) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
Shinohara, Genki*; Sato, Nobuaki*; Kirishima, Akira*; Tochiyama, Osamu*; Sato, Soichi
Proceedings of 16th Iketani Conference: Masuko Symposium, p.153 - 160, 2006/11
For the recovery of uranium from spent nuclear fuel, the sulfide reprocessing process has been proposed. The process consists of voloxidation and sulfurization steps followed by either magnetic separation or selective leaching steps. In this process, selective sulfurization of the rare-earth elements is applied, while the uranium oxide remains unreacted. The sulfurization of rare-earth oxides R
O (R=Nd, Eu) was examined using CS, and found that they formed oxysulfide and sulfides even at temperatures lower than 500
C. From the results of the sulfurization of RO in the simulated spent fuel, it was found that RO for Nd and Eu were selectively sulfurized by CS at 500C forming NdS and EuS, respectively, while uranium remained as UO. Effects of sulfurizing temperature and time were also investigated and compared with the results of thermodynamic consideration.
Oikawa, Kenichi; Kiyanagi, Yoshiaki*; Shinohara, Takenao; Kai, Tetsuya; Watanabe, Kenichi*; Uritani, Akira*; Hori, Genki*; Hirata, Yuho*
no journal, ,
Katata, Genki*; Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; et al.
no journal, ,
no abstracts in English
