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Toshiaki Nanazawa Tetsuya Kouno Gaku Sakashita Takashi Nakaura 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(3):176-184
ABSTRACTThis paper describes the development of a partial factor design method on the bending strength of piles for the Japanese Specifications for Highway Bridges. First, uncertainties in mobilised bending moments and yield bending moments were evaluated by Monte Carlo simulations. Second, the reliability of piles designed by the previous specifications were evaluated on the basis of reliability analysis considering uncertainties in the mobilised bending moments, yield bending moments, and other factors. Finally, a partial factor design method utilising a survey subsurface investigation method and ground type was developed to reach target reliability levels determined by the Standards. 相似文献
86.
Hideki Iwano Tohru Danhara Takashi Yuguchi Takafumi Hirata Masatsugu Ogasawara 《地学学报》2019,31(3):247-256
Anorthositic series apatites of the Duluth Complex, Minnesota, USA, have high spontaneous fission‐track densities of up to ~107 cm–2 and a homogeneous age of ~900 Ma, allowing high‐precision fission‐track dating based on LA–ICP–MS U analysis. Absolute fission‐track dating, track‐length measurement and chemical composition analysis were performed to evaluate a cooling history, which is essential for age reference materials. Preliminary inverse modelling for a sample with a shortened track‐length distribution yielded a monotonic cooling history from ~100°C at 925 Ma. The apatites incur an over‐etching problem when employing the commonly used etching protocol involving 5.5 M HNO3. 相似文献
87.
Philipp R. Heck Christopher Herd Jeffrey N. Grossman Dmitry Badjukov Audrey Bouvier Emma Bullock Hasnaa Chennaoui‐Aoudjehane Vinciane Debaille Tasha L. Dunn Denton S. Ebel Ludovic Ferrire Laurence Garvie Jrme Gattacceca Matthieu Gounelle Richard Herd Trevor Ireland Emmanuel Jacquet Robert J. Macke Tim McCoy Francis M. McCubbin Takashi Mikouchi Knut Metzler Mathieu Roskosz Caroline Smith Meenakshi Wadhwa Linda Welzenbach‐Fries Toru Yada Akira Yamaguchi Ryan A. Zeigler Michael Zolensky 《Meteoritics & planetary science》2019,54(7):1397-1400
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Nutrients,light and phytoplankton production in the shallow,tropical coastal waters of Bandon Bay,Southern Thailand 下载免费PDF全文
Takashi Yoshikawa Kosuke Tomizawa Yuki Okamoto Kazuya Watanabe Jintana Salaenoi Kenichi Hayashizaki Hisashi Kurokura Satoshi Ishikawa 《Marine Ecology》2017,38(6)
Phytoplankton primary production and its regulation by light and nutrient availability were investigated in the shallow, tropical coastal waters of Bandon Bay, Southern Thailand. The bay was meso‐eutrophicated and highly turbid, receiving river water discharge. Water column stratification was consistently weak during both rainy and dry seasons. Dissolved inorganic nitrogen (DIN) was higher off the river mouth than in the other regions, suggesting that river water discharge was a main source of DIN. By contrast, dissolved inorganic phosphorus (DIP) showed a significant negative correlation with total water depth, implying that regeneration around the sea floor was an important source of DIP. Surface DIN and DIP showed positive correlations with surface primary production (PP) and water column primary productivity (ΣPP*), respectively. The combined correlation and model analyses indicate that total water depth had an ambivalent influence on water column primary production (ΣPP); shallower water depth induced more active regeneration of nutrients, but it also caused higher turbidity and lower light availability as a result of enhanced resuspension of sediments. Furthermore, there was a vertical constraint for phytoplankton during the rainy season: total water depth tended to be shallower than euphotic zone depth. In conclusion, light limitation and vertical constraint owing to shallow water depth appear to be more important than nutrient limitation for water column primary production in Bandon Bay. 相似文献
89.
Takashi T. Sakamoto L. Shogo Urakawa Hiroyasu Hasumi Miho Ishizu Sachihiko Itoh Teruhisa Komatsu Kiyoshi Tanaka 《Journal of Oceanography》2017,73(1):39-54
A numerical simulation of Otsuchi Bay located on the northeast coast of the Honshu, the largest island of Japan, is conducted, using an ocean general circulation model (OGCM) with a nested-grid system in order to illustrate seasonal variability of the circulation in the bay. Through a year, an anticlockwise circulation is dominant in the bay, as observational studies have implied, although it is modified in the bay-mouth-half of the bay in winter. In addition, there is an intense outflow at the surface layer during spring to autumn, influenced by river water discharge. Intrusion of the Pacific water into the bay is influened by mean circulations, but it is also influenced by baroclinic tides from spring to autumn. Pacific water intrusions affected by baroclinic tides may have an impact on the environment in Otsuchi Bay. 相似文献
90.
Sumio Matsuura Takashi Okamoto Shiho Asano Hikaru Osawa Tatsuya Shibasaki 《Environmental Earth Sciences》2017,76(10):362
The displacement of a relatively small reactivated landslide in a snowy area in Japan was monitored over a long period. The displacement rate of the landslide, which was approximately of 20 mm d?1 before the formation of snow cover, decelerated drastically during the continuous snow cover period every winter period. Possible causes included reduction in the amount of water that reached the ground surface (MR: meltwater and/or rainwater) and increase in snow load. Given that the actual displacement of the landslide was far below the predicted value based on the relationship between landslide displacement and MR immediately before the continuous snow cover period, the deceleration of landslide displacement was more likely attributable to the increase in snow load than to the reduction in MR. An investigation of the link between snow load and landslide displacement showed a negative logarithmic relationship. A dynamic analysis based on the limit equilibrium method showed that snow load increases the effective normal stress and the stability of a landslide in which the mean inclination angle of the slip surface is smaller than the internal friction angle. The stability of the actual slope was also analyzed by conducting soil tests on samples collected at the site and using the resultant parameters. The analysis also showed that the increase in snow load increases the safety factor and reduces the landslide displacement. The displacement of a relatively small landslide that has a shallow slip surface was found to be greatly influenced by snow cover. 相似文献