A basic study on the application of LRFD in “the technical standard for port and harbour facilities in Japan”: a case of gravity type quay wall in a persistent design situation     

Masahiro Takenobu  Masafumi Miyata  Yu Otake  Takehiko Sato 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(3):195-204

ABSTRACT

The Partial Factor Method (PFM) based on the Level 1 reliability design method was introduced in 2007 to the Technical Standards for Port and Harbour Facilities (TSPHF-2007) in Japan. After nearly 10 years of practical use of TSPHF-2007, the design standard has been revised based on requests from the practitioners who recommend the transition from the PFM to the Load Resistance Factor Design (LRFD). In this paper, we discuss the setting method of the target failure probability to determine the partial factors based on code calibration. Furthermore, we examine the impacts of implementing the LRFD concept to the TSPHF by taking the sliding and overturning of a gravity type quay wall as an example to represent port and harbour facilities. We found no practical difference in caisson width derived using the LRFD and the PFM, whereas the degree of matching of the target failure probability was somewhat more precise for the PFM. This finding indicates that the LRFD is a more reasonable design method than the PFM in terms of the simplicity of the performance function itself and the ease of engineering interpretation during the design procedure.  相似文献   

Vertical material flux under seasonal sea ice in the Okhotsk Sea north of Hokkaido, Japan     

Takehiko Hiwatari  Kunio Shirasawa  Yasushi Fukamachi  Ryuichi Nagata  Tomoyoshi Koizumi  Hiroshi Koshikawa  Kunio Kohata 《Polar Science》2008,2(1):41-54

Downward material fluxes under seasonal sea ice were measured using a time-series sediment trap installed at an offshore site in the Okhotsk Sea north of Hokkaido, Japan, from 13 January to 23 March 2005. The maximum fluxes of lithogenic material (753 mg m⁻² day⁻¹) and organic matter (mainly detritus; 333 mg m⁻² day⁻¹) were recorded during the period in which sea ice drifted ashore and increased in extent, from 13 January to 9 February. Organic matter as fecal pellets (81–93 mg m⁻² day⁻¹) and opal as biosilica (51–67 mg m⁻² day⁻¹), representing diatom fluxes, were abundant in sediment trap samples obtained during the period of full sea ice coverage from 10 February to 9 March. Microscopic observations revealed that fecal pellets were largely diatom frustules, suggesting that zooplankton actively grazed on ice algae during the period of full sea ice coverage. During the period of retreating sea ice, from 10 to 23 March, the phytoplankton flux showed a rapid increase (from 9.5 to 22.5 × 10⁶ cells m⁻² day⁻¹), reflecting their release into the water column as the sea ice melted. Our results demonstrate that the quantity and quality of sinking biogenic and lithogenic materials vary with the seasonal extent of sea ice in mid-winter.  相似文献   

Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science     

Yoshimasa Tanaka  Atsuki Shinbori  Tomoaki Hori  Yukinobu Koyama  Shuji Abe  Norio Umemura  Yuka Sato  Manabu Yagi  Satoru UeNo  Akiyo Yatagai  Yasunobu Ogawa  Yoshizumi Miyoshi 《极地研究(英文版)》2013,(4):231-240

To comprehensively understand the Arctic and Antarctic upper atmosphere, it is often crucial to analyze various data that are obtained from many regions. Infrastructure that promotes such interdisciplinary studies on the upper atmosphere has been developed by a Japanese inter-university project called the Inter-university Upper atmosphere Global Observation Network （1UGONET）. The objective of this paper is to describe the infrastructure and tools developed by IUGONET. We focus on the data analysis software. It is written in Interactive Data Language （IDL） and is a plug-in for the THEMIS Data Analysis Software suite （TDAS）, which is a set of IDL libraries used to visualize and analyze satellite- and ground-based data. We present plots of upper atmospheric data provided by IUGONET as examples of applications, and verify the usefulness of the software in the study of polar science. We discuss IUGONET＇s new and unique developments, i.e., an executable file of TDAS that can run on the IDL Virtual Machine, IDL routines to retrieve metadata from the IUGONET database, and an archive of 3-D simulation data that uses the Common Data Format so that it can easily be used with TDAS.  相似文献   

Occurrence of xenobiotic ligands for retinoid X receptors and thyroid hormone receptors in the aquatic environment of Taiwan     

Chien-Hsun Chen  Pei-Hsin Chou  Masanobu Kawanishi  Takashi Yagi 《Marine pollution bulletin》2014

Various synthetic compounds are frequently discharged into the environment via human activities. Among them, certain contaminants may disrupt normal physiological functions of wildlife and humans via interactions with nuclear receptors. To protect human health and the environment, it is important to detect environmental ligands for human nuclear receptors. In this study, yeast-based reporter gene assays were used to investigate the occurrence of xenobiotic ligands for retinoid X receptors (RXR) and thyroid hormone receptors (TR) in the aquatic environment of Taiwan. Experimental results revealed that RXR agonist/antagonist activity was detected in river water and sediment samples. In particular, high RXR agonist/antagonist activity was found in the samples collected near river mouths. Additionally, few samples also elicited significant TR antagonist activity. Our findings show that the aquatic environment of Taiwan was contaminated with RXR and TR ligands. Further study is necessary to identify these xenobiotic RXR and TR agonists and antagonists.  相似文献   

Timescale of material circulation in subduction zone: U–Pb zircon and K–Ar phengite double‐dating of the Sanbagawa metamorphic complex in the Ikeda district,central Shikoku,southwest Japan     

Mitsuhiro Nagata  Kazuhiro Miyazaki  Hideki Iwano  Tohru Danhara  Hideyuki Obayashi  Takafumi Hirata  Koshi Yagi  Yoshikazu Kouchi  Koshi Yamamoto  Shigeru Otoh 《Island Arc》2019,28(4)

We have estimated the timescale of material circulation in the Sanbagawa subduction zone based on U–Pb zircon and K–Ar phengite dating in the Ikeda district, central Shikoku. The Minawa and Koboke units are major constituents of the high‐P Sanbagawa metamorphic complex in Shikoku, southwest Japan. For the Minawa unit, ages of 92–81 Ma for the trench‐fill sediments, are indicated, whereas the age of ductile deformation and metamorphism of garnet and chlorite zones are 74–72 Ma and 65 Ma, respectively. Our results and occurrence of c. 150 Ma Besshi‐type deposits formed at mid‐ocean ridge suggest that the 60‐Myr‐old Izanagi Plate was subducted beneath the Eurasian Plate at c. 90 Ma, and this observation is consistent with recent plate reconstructions. For the Koboke unit, the depositional ages of the trench‐fill sediments and the dates for the termination of ductile deformation and metamorphism are estimated at c. 76–74 and 64–62 Ma, respectively. In the Ikeda district, the depositional ages generally become younger towards lower structural levels in the Sanbagawa metamorphic complex. Our results of U–Pb and K–Ar dating show that the circulation of material from the deposition of the Minawa and Koboke units at the trench through an active high‐P metamorphic domain to the final exhumation from the domain occurred continuously throughout c. 30 Myr (from c. 90 to 60 Ma).  相似文献   

Predictability of storm wave heights in the ice-free Beaufort Sea     

Takehiko Nose  Adrean Webb  Takuji Waseda  Jun Inoue  Kazutoshi Sato 《Ocean Dynamics》2018,68(10):1383-1402

A predictability study on wave forecast of the Arctic Ocean is necessary to help identify hazardous areas and ensure sustainable shipping along the trans-Arctic routes. To assist with validation of the Arctic Ocean wave model, two drifting wave buoys were deployed off Point Barrow, Alaska for two months in September 2016. Both buoys measured significant wave heights exceeding 4 m during two different storm events on 19 September and 22 October. The NOAA-WAVEWATCH III^? model with 16-km resolution was forced using wind and sea ice reanalysis data and obtained general agreement with the observation. The September storm was reproduced well; however, model accuracy deteriorated in October with a negative wave height bias of around 1 m during the October storm. Utilising reanalysis data, including the most up-to-date ERA5, this study investigated the cause: grid resolution, wind and ice forcing, and in situ sea level pressure observations assimilated for reanalysis. The analysis has found that there is a 20% reduction of in situ SLP observations in the area of interest, presumably due to fewer ships and deployment options during the sea ice advance period. The 63-member atmospheric ensemble reanalysis, ALERA2, has shown that this led to a larger ensemble spread in the October monthly mean wind field compared to September. Since atmospheric physics is complex during sea ice advance, it is speculated that the elevated uncertainty of synoptic-scale wind caused the negative wave model bias. This has implications for wave hindcasts and forecasts in the Arctic Ocean.  相似文献   

Marine protected areas in Japan: Institutional background and management framework     

Nobuyuki Yagi  Akira P. TakagiYukiko Takada  Hisashi Kurokura 《Marine Policy》2010

Information on the location and area for all MPAs in Japan was collected through a comprehensive survey targeting government officials and local stakeholders. It was verified that at least 1161 MPAs exist in Japan. Of these, 1055 are implemented in conjunction with fishery regulations in the form of no-take zones. More than 30% of the individual MPAs in Japan were established by self-imposed instruments agreed by members of fishery co-management organizations. It was suggested that the autonomous MPAs are not a product of simple altruism, but rather are logical extensions of the tenure system guaranteed by the government legal system.  相似文献   

霞浦湖沉积物需氧速率的研究   总被引：5，自引：1，他引：5  

范成新  相崎守弘  福岛武彦  松重一夫 《海洋与湖沼》1998,29(5):508-513

１９９５年２月,用大口径采样器采集日本霞浦湖土浦湾和湖心柱状沉积物样品,在２０℃恒温蔽光封闭条件下,研究了该湖泊沉积物需氧（ＳＯＤ）速率及实验前后上覆水和间隙水中形态营养物浓度变化,结果表明,实验初期（０－５ｈ）ＳＯＤ速率随时间呈线性上升,大于５ｈ后呈非线性下降,对线性部分计算的ＳＯＤ速率约在０．６－１．８ｍｇ／（ｍ＾２．ｄ）之间,实验发现,上覆水和表层间隙水中形态营养物Ｆｅ（Ⅱ）,ＮＨ＾＋４－Ｎ  相似文献   

Distribution and characteristics of landslides induced by the Iwate–Miyagi Nairiku Earthquake in 2008 in Tohoku District, Northeast Japan     

Hiroshi Yagi  Go Sato  Daisuke Higaki  Miki Yamamoto  Takanari Yamasaki 《Landslides》2009,6(4):335-344

The Iwate–Miyagi Nairiku Earthquake in 2008, whose seismic intensity was M. 7.2 in Japan Meteorological Agency (JMA) scale, induced innumerable landslides on the southern flank of Mt. Kurikoma volcano allocated along the Ou Backbone Range in Northeast Japan. Most landslides are detected in a hanging wall side of the seismic fault. Those landslides are classified into five types: deep-seated slide, debris slide, shallow debris slide, secondary shallow debris slide, and debris flow. Most common landslide types induced by the earthquake are shallow debris slides and subsequent debris flows. They are intensively distributed along steep gorges incising a volcanic skirt of Mt. Kurikoma, consisting of welded ignimbrite of the Pleistocene age. Debris flows are also distributed even along gentle river floors in the southern lower flank of the volcano. The area of densely distributed debris slides, shallow debris slides, and debris flows is concordant with that of severe seismic tremor. Thus, genetic processes of landslides induced by the Iwate–Miyagi Nairiku Earthquake in 2008 are attributed to multiple causative factors such as geology, topography, and seismic force.  相似文献   

Petrology and magnetic properties of the Chiang Khan,Thailand, meteorite     

Dr. K. Yagi  Dr. M. Kimura  Dr. Y. Kuroda  Dr. K. Momose 《Mineralogy and Petrology》1989,40(3):173-182

Summary The Chiang Khan meteorite fell on 18th November, 1981 at Chiang Khan, Thailand. It consists of olivine, orthopyroxene, clinopyroxene, Fe-Ni metal, troilite, chromite, plagioclase, glass, and phosphate in order of abundance. Olivine forms barred or porphyritic chondrules, and its composition is uniform (average Fo_80.2), close to the average composition of olivine in equilibrated H chondrites. Orthopyroxene and clinopyroxene also have compositions similar to those in equilibrated H chondrites. Both well-defined chondrules and their broken fragments are present in the recrystallized matrix. Microcrystalline plagioclase and clinopyroxene often occur in the groundmass of chondrules, but clear interstitial plagioclase is absent. Chemical composition of chromite plots in the field of chromites in H chondrites. Chiang Khan meteorite is thus classified as an equilibrated H 5 type chondrite. The equilibrium temperatures estimated by using mineral pairs are as follows: Opx-Cpx 800–900°C; Ol-Chromite 510°C.Water content is 0.24 wt %, and the hydrogen isotopic composition (D) is –89.5In the thermal demagnetization experiment magnetization steadily decreased from 0 to 500°C, whereas the remanent magnetization obtained in the A.C. demagnetization experiment is very unstable, probably owing to the large grain size of the Fe-Ni metal.With 9 Figures  相似文献