- 著者
- TAKASHI TOMIYASU MASAYUKI EGUCHI HAYAO SAKAMOTO KATSURO ANAZAWA RYUSUKE IMURA
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.40, no.3, pp.253-263, 2006 (Released:2007-06-22)
- 参考文献数
- 21
- 被引用文献数
- 3 11
The atmospheric concentration of mercury was determined daily for 3 years (July 1999-March 2002) in Kagoshima City to clarify the seasonal variation of mercury levels and the influence of mercury emitted from Sakurajima. The atmospheric mercury was collected on a porous gold collector at Kagoshima University approximately 11 km west of Sakurajima and the amount of mercury was determined by cold vapor atomic absorption spectrometry (CVAAS). A loss of temperature dependency was found for the east wind in 1999. However, in 2001, high temperature dependency was observed for all wind directions with the easing of volcanic activity. Short-term movement in the atmospheric concentration of mercury was also investigated by making measurements every two hours over a three-day period at heights of 3 and 12 m. This operation was carried out about every two months in the year 2001 at Kagoshima University. The atmospheric mercury concentration was higher in the daytime than nighttime showing temperature dependency: the concentration at 3 m (Hg(3m)) ranged from 1.65 to 17.9 ng m-3 (5.96 ± 3.47 ng m-3) in the daytime and 1.50 to 12.8 ng m-3 (4.20 ± 2.33 ng m-3) overnight, while that at 12 m (Hg(12m)) ranged from 1.24 to 29.4 ng m-3 (4.74 ± 3.61 ng m-3) and 1.38 to 14.8 ng m-3 (4.50 ± 2.85 ng m-3), respectively. The variation in Hg(3m) from day to night was considerably larger than that in Hg(12m). As a result, Hg(3m) was higher than Hg(12m) in the daytime and lower in the nighttime. On the other hand, the concentration gradient showed a high degree of dependency on solar radiation. These observations suggested that mercury is emitted from the ground with an increase in solar radiation and rise of the temperature in the daytime and deposits with the fall of temperature at nighttime. The influence of rain and volcanic activity on the periodic variation of mercury is also discussed in detail.
- 著者
- Kiyoshi KOBAYASHI Masayuki EGUCHI Akira OI Kazuya AOKI Kiyoyuki KAITO
- 出版者
- 公益社団法人 土木学会
- 雑誌
- Journal of JSCE (ISSN:21875103)
- 巻号頁・発行日
- vol.1, no.1, pp.551-568, 2013 (Released:2013-12-27)
- 参考文献数
- 20
- 被引用文献数
- 4
This study proposes a methodology to find the optimal inspection policy for road pavement with uncertain deterioration processes. Since the deterioration progresses are characterized by a lot of uncertainty, the pavement conditions cannot be deterministically evaluated unless the inspection or repair activities are carried out. The road administrators have to decide whether repair should be implemented based upon the results of inspection. In this paper, the value of the inspection is evaluated by using the real option theory, and the optimal inspection and repair model is formulated to investigate the optimal inspection frequencies and repair policy, which may minimize the expected life cycle costs. Finally, the validity of the methodology presented in the paper is investigated by a case study dealing with the expressway in the real world.