Application of distinct element analysis to three simple block models aimed at practical application to toppling failure of fissured rock slopes     

Tsuyoshi Ishida 《Computers and Geotechnics》1990,9(4):341-353

To examine the accuracy and the chracteristics of the Distinct Element Method (DEM) which has non-deformable elements, the results simulated by the DEM were compared to the results of experiments and/or theories for three simple block models of a pillar, a mass and a toppling model. Consequently, it was elucidated that the DEM is a good numerical method which can be effectively applied to toppling failure of real fissured rock slopes.  相似文献   

343 pp., Hardcover, US$ 143.00/Dfl. 250.00E. Juhàcovà, Seismic Effects on Structures, Elsevier (1991).     

Tsuyoshi Ishida 《Engineering Geology》1992,32(4):286-287

  相似文献   

Application of the Distinct Element Method for analysis of toppling observed on a fissured rock slope   总被引：1，自引：0，他引：1  

T. Ishida  M. Chigira  S. Hibino 《Rock Mechanics and Rock Engineering》1987,20(4):277-283

  相似文献   

A simple, rheological model for plate motion to explain episodic volcanism and tectonism: An application of whitehead and gans' fault model     

Keisuke Ito 《Tectonophysics》1979,57(1):85-94

A simple, rheological model is presented for plate motions to explain episodic volcanism and tectonism. A lithospheric plate is modelled by a gliding block and the basal edge of the sinking plate is modelled by a stick-slip-like fault system. The friction force is assumed to have a maximum at a critical sliding velocity. When the sliding velocity at the basalt edge exceeds the critical velocity, the basal edge system becomes unstable and the plate accelerates. Conditions that the model system has a periodic solution are obtained and parameters of the system are evaluated from rheological properties of the mantle and configurations of the plate. Results suggest that a plate moves nearly steadily over a long period of time but it accelerates sharply during a very short period of time. The accelerating period is considered to correspond to the episodes of active volcanism and tectonism.  相似文献   

Agricultural typology and land use: Reeds, L.G., ed. (1973): proceedings of the agricultural typology commission meeting, McMaster University, Hamilton, Ont., 1972. 350 pp., tables, maps and diagrams. $12.00     

H. Ishida 《Geoforum》1975,6(3-4)

  相似文献   

Arsenic contamination of groundwater and agricultural soil irrigated with the groundwater in Mekong Delta,Vietnam     

Yi Huang  Keisuke Miyauchi  Ginro Endo  Le Dinh Don  Nguyen Cong Manh  Chihiro Inoue 《Environmental Earth Sciences》2016,75(9):757

  相似文献   

Size and taxonomic plankton community structure and carbon flow at the equator, 175‡E during 1990–1994     

J. Ishizaka  K. Harada  K. Ishikawa  H. Kiyosawa  H. Furusawa  Y. Watanabe  H. Ishida  K. Suzuki  N. Handa  M. Takahashi 《Deep Sea Research Part II: Topical Studies in Oceanography》1997,44(9-10)

Size and taxonomic structure of plankton community carbon biomass for the 0.2–2000 μm equivalent spherical diameter range were determined at the equator at 175°E in September 1990–1993 and April 1994. Total biomass of the plankton community ranged from 1944 to 3448 mg C m⁻². Phytoplankton, zooplankton and bacteria carbon biomasses were 604–1669 mg C m^-2, 300–797 mg C m², and 968–1200 mg C m^-2, and the percentages were 31–54%, 15–26%, and 29–54%, respectively. Biomass of heterotrophic bacteria was always the largest fraction andProchlorococcus biomass was second. Heterotrophic and autotrophic flagellates and dinoflagellates in the nanoplankton size range and copepods (adults and copepodites) in the mesoplankton range were also high. Relatively small biomass was observed in the microplankton size range. The differences in integrated biomass of plankton community for El Nin˜o type oligotrophic conditions of September 1990–1993 and non-El Nifio type mesotrophic conditions of April 1994 were generally small compared with the interannual difference during 1990–1993. However, the percentage ofProchlorococcus in phytoplankton carbon biomass was larger in non-El Nin˜o year. Biomasses of cyanobacteria, diatom, dinoflagellates, nauplii of copepods, and crustaceans other than copepods were larger in the non-El Nin˜o year. Primary production increased significantly from El Nin˜o to non-El Nin˜o years. Carbon flow through the plankton food chain was estimated using the plankton carbon biomass data, primary production measurements, and published empirical relationships.  相似文献   

Meridional distribution and carbon biomass of autotrophic picoplankton in the Central North Pacific Ocean during late northern summer 1990     

Joji Ishizaka  Hiroshi Kiyosawa  Kazunori Ishida  Kimitoshi Ishikawa  Masayuki Takahashi 《Deep Sea Research Part I: Oceanographic Research Papers》1994,41(11-12)

The meridional distribution of autotrophic picoplankton groups in the central north Pacific was studied during the late northern summer of 1990. Sampling was along a section at 175°N which extended from 45°N to 8°S. The section is far from coastal regions and included subarctic, central gyre, and equatorial areas. Five autotrophic picoplankton groups, autotrophic microflagellate, red-fluorescing picoplankton,Synechococcus, prochlorophyte, and orange-fluorescing picoplankton, were identified from samples taken at stations distributed along this section. These five groups showed distinctive differences in their meridional and vertical distributions. The autotrophic microflagellates and red-fluorescing picoplankton showed distributions that were similar to that of chlorophyll a, which was dominated by the <3 μm size fraction. However, the vertical distribution of these groups was different.Synechococcus was found mostly in surface waters (PAR<10%) and was particularly abundant in the Kuroshio Extension and south of the equatorial region where the nitracline was shallow (50–75 m). Prochlorophytes were abundant in the deep euphotic layer (PAR 1-0.1%) from the south of the Kuroshio Extension to the south of the equatorial area. Orange-fluorescing picoplankton, which may be one kind of cyanobacteria but is larger than typical Synechococcus, were mostly distributed in the oligotrophic surface waters of the central gyre. The carbon biomass estimates for these organisms showed that these five groups dominated in different areas. The vertical distribution of carbon biomass did not correspond to that of chlorophyll a in the central gyre and south of the equator because of the larger carbon/ chlorophyll a ratio of Synechococcus and orange-fluorescing picoplankton relative to that of the other picoplankton.  相似文献   

Anticyclonic eddy caused by the Soya Warm Current in an Okhotsk OGCM     

Keisuke Uchimoto  Humio Mitsudera  Naoto Ebuchi  Yasumasa Miyazawa 《Journal of Oceanography》2007,63(3):379-391

  相似文献   

Centrifugal forces estimated from trajectories of drifting buoys in winding paths of the Kuroshio     

Keisuke Taira  Toshihiko Teramoto  Kensuke Takeuchi 《Journal of Oceanography》1987,43(2):104-110

Radii and angular velocities in the motions of drifting buoys deployed in the Kuroshio are estimated by fitting circles to the trajectories of two drifting buoys, one with a drogue at 300 m depth and the other at 800 m depth. The buoys were deployed in the Kuroshio where it was flowing counter-clockwise around the large cold water mass south of Honshu. The same technique was applied to two drifting buoys with drogues at 300 m depth placed in the Kuroshio where it flowed clockwise around Oshima Island in Sagami Bay. The centrifugal forces were 7% and 6% as large as the Coriolis forces in the Kuroshio around the cold water mass, and they were –56% and –42% as large as the Coriolis forces in the current around the Oshima Island. The temperature gradient observed in the Oshima-West Channel suggested that the pressure gradient there was smaller due to the centrifugal force acting against the Coriolis force than the pressure gradient to be balanced with the Coriolis force.  相似文献