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排序方式: 共有106条查询结果,搜索用时 0 毫秒
31.
ICT-based remediation with knowledge information management is presented for the pump-and-treat method of contaminated groundwater. The usefulness of ICT is discussed for monitoring contaminants and groundwater level, transferring data between the remediation well and the remote remediation center, and decision support analysis for controlling the remediation well. A prototype system was developed and applied to field measurement. The prototype system performed reliably for ~600 days. As a decision support analysis, a fuzzy inference model is discussed. The membership functions were determined based on simple reliability theory. The effectiveness of the proposed method was assessed by numerical simulations. The simulation results suggest that the proposed method is likely to reduce the pumped quantity compared to PID control or an engineer’s empirical knowledge. Analysis results are also shown for cancer risks from contaminants and ground settlement risks due to excess pumping up of groundwater. 相似文献
32.
Richard J. Bathurst Tony M. Allen Yoshihisa Miyata Sina Javankhoshdel Nezam Bozorgzadeh 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2019,13(3):214-225
ABSTRACTMechanically stabilized earth (MSE) walls must be designed with adequate margins of safety against internal stability failure described by tensile strength and pullout limit states. Probabilities of failure (or reliability index) will vary strongly with the accuracy of the underlying models that appear in limit state performance functions. In this paper, prior work by the authors and co-workers on this topic is reviewed. Relative performance is explored in the context of the reliability (or probability of failure) of steel and polymeric reinforcing elements in MSE walls using limit state performance functions with load and resistance models having different accuracy. 相似文献
33.
Regional landslide susceptibility following the Mid NIIGATA prefecture earthquake in 2004 with NEWMARK’S sliding block analysis 总被引:1,自引:0,他引:1
This study proposes a calculation method for regional earthquake-induced landslide susceptibility that applies the permanent seismic displacement calculated using Newmark’s sliding block analysis with estimated vertical and horizontal seismic motions. The proposed method takes into account the direction of slope failure based on the specified slope azimuth. The study results reveal the importance of predominant slope failure direction using a simple infinite slope model subjected to earthquakes. The target area for the earthquake-induced landslide susceptibility analysis constituted a region of more than 2000 km2 surrounding the epicenter of the Mid Niigata prefecture earthquake in 2004. An earthquake-induced landslide susceptibility map was created based on the proposed method with a specific combination of friction angle and cohesion, and the resulting data were compared to the landslide inventory map produced from aerial photographs following the Mid Niigata prefecture earthquake in 2004. To create the susceptibility map, geomaterial cohesion values for the slope were back-calculated to satisfy the minimum safety factor in the static state. This study also proposes a calculation method for the prediction rate and determines the back-calculated strength parameters of geomaterials. The proposed regional landslide susceptibility map will be useful for understanding potential slope failure locations and magnitude of damage, as well as for planning field investigation and preventing secondary disasters immediately after earthquakes. 相似文献
34.
Masato Joshima Yoshihisa Okuda Fumitoshi Murakami Kiyoyuki Kishimoto Eiichi Honza 《Geo-Marine Letters》1987,6(4):229-234
Magnetic anomalies measured in the central to western half of the Solomon Sea, when considered with other magnetic data, reveal the existence of linear patterns. Magnetic lineation anomaly models of the Cenozoic, 65 to 0 Ma, suggest that an age between 34 and 28 Ma and a half-rate spreading speed of 5.8 cm/yr for the northern flank of a former spreading center best fits our present magnetic data in the Solomon Sea Basin. Heat flow and bathymetry data support this preferred model. 相似文献
35.
Direct injection of CO(2) into the deep ocean is receiving increasing attention as a way to mitigate increasing atmospheric CO(2) concentration. To assess the potential impact of the environmental change associated with CO(2) sequestration in the ocean, we studied the lethal and sub-lethal effects of raised CO(2) concentration in seawater on adult and early stage embryos of marine planktonic copepods. We found that the reproduction rate and larval development of copepods are very sensitive to increased CO(2) concentration. The hatching rate tended to decrease, and nauplius mortality rate to increase, with increased CO(2) concentration. These results suggest that the marine copepod community will be negatively affected by the disposal of CO(2). This could decrease on the carbon export flux to the deep ocean and change the biological pump. Clearly, further studies are needed to determine whether ocean CO(2) injection is an acceptable strategy to reduce anthropogenic CO(2). 相似文献
36.
Abundance of deep-sea meiobenthos off Sanriku, Northeastern Japan was studied quantitatively using sediment samples collected by box corers or an Okean grab. Sampling stations were established along a line transect which covered areas from off the mouth of Otsuchi Bay to the abyssal plain of the western Pacific crossing over the Japan Trench (water depths from 120 m to 7460 m). Abundance of meiobenthos decreased linearly with water depth down to 1503 m and became constant at stations deeper than 4130 m. Nematodes predominated over the other taxonomic groups at all stations. An equation to estimate meiofaunal abundance from several sediment characteristics, which was previously proposed by the first author based on data from tropical and subtropical regions of the western Pacific, was applied to the present boreal area. At one station where the Okean grab was used, the estimated value was 4.7 times more than the observed one. Except for the station, however, observed values fell within the confident range of estimated values. The estimated values were always higher than the observed ones at boxcorer stations, whereasvice versa at Okean-grab stations. These results suggested that keen attention is necessary in selecting sampling gear for ecological studies of deep-sea meiobenthos. 相似文献
37.
Masato Joshima Yoshihisa Okuda Fumitoshi Murakami Kiyoyuki Kishimoto Eiichi Honza 《Geo-Marine Letters》1986,6(4):229-234
Magnetic anomalies measured in the central to western half of the Solomon Sea, when considered with other magnetic data, reveal the existence of linear patterns. Magnetic lineation anomaly models of the Cenozoic, 65 to 0 Ma, suggest that an age between 34 and 28 Ma and a half-rate spreading speed of 5.8 cm/yr for the northern flank of a former spreading center best fits our present magnetic data in the Solomon Sea Basin. Heat flow and bathymetry data support this preferred model. 相似文献
38.
Hiroshi Kitazato Takeshi NakatsukaMotohiro Shimanaga Jota KandaWonn Soh Yoshihisa KatoYoshihiro Okada Akio YamaokaToshiyuki Masuzawa Koji SuzukiYoshihisa Shirayama 《Progress in Oceanography》2003,57(1):3-16
Deep-sea benthic ecosystems are mainly sustained by sinking organic materials that are produced in the euphotic zone. “Benthic-pelagic coupling” is the key to understanding both material cycles and benthic ecology in deep-sea environments, in particular in topographically flat open oceanic settings. However, it remains unclear whether “benthic-pelagic coupling” exists in eutrophic deep-sea environments at the ocean margins where areas of undulating and steep bottom topography are partly closely surrounded by land. Land-locked deep-sea settings may be characterized by different particle behaviors both in the water column and in relation to submarine topography. Mechanisms of particle accumulation may be different from those found in open ocean sedimentary systems. An interdisciplinary programme, “Project Sagami”, was carried out to understand seasonal carbon cycling in a eutrophic deep-sea environment (Sagami Bay) with steep bottom topography along the western margin of the Pacific, off central Japan. We collected data from ocean color photographs obtained using a sea observation satellite, surface water samples, hydrographic casts with turbidity sensor, sediment trap moorings and multiple core samplings at a permanent station in the central part of Sagami Bay between 1997 and 1998. Bottom nepheloid layers were also observed in video images recorded at a real-time, sea-floor observatory off Hatsushima in Sagami Bay. Distinct spring blooms were observed during mid-February through May in 1997. Mass flux deposited in sediment traps did not show a distinct spring bloom signal because of the influence of resuspended materials. However, dense clouds of suspended particles were observed only in the spring in the benthic nepheloid layer. This phenomenon corresponds well to the increased deposition of phytodetritus after the spring bloom. A phytodetrital layer started to form on the sediment surface about two weeks after the start of the spring bloom. Chlorophyll-a was detected in the top 2 cm of the sediment only when a phytodetritus layer was present. Protozoan and metazoan meiobenthos increased in density after phytodetritus deposition. Thus, “benthic-pelagic coupling” was certainly observed even in a marginal ocean environment with undulated bottom topography. Seasonal changes in features of the sediment-water interface were also documented. 相似文献
39.
Sub-Lethal Effects of Elevated Concentration of CO<Subscript>2</Subscript> on Planktonic Copepods and Sea Urchins 总被引:2,自引:0,他引:2
Data concerning the effects of high CO2 concentrations on marine organisms are essential for both predicting future impacts of the increasing atmospheric CO2 concentration and assessing the effects of deep-sea CO2sequestration. Here we review our recent studies evaluating the effects of elevated CO2 concentrations in seawater on the mortality and egg production of the marine planktonic copepod, Acartia steueri, and on the fertilization rate and larval morphology of sea urchin embryos, Hemicentrotus pulcherrimus and Echinometra mathaei. Under conditions of +10,000 ppm CO2 in seawater (pH 6.8), the egg production rates of copepods decreased significantly. The survival rates of adult copepods
were not affected when reared under increased CO2 for 8 days, however longer exposure times could have revealed toxic effects of elevated CO2 concentrations. The fertilization rate of sea urchin eggs of both species decreased with increasing CO2 concentration. Furthermore, the size of pluteus larvae decreased with increasing CO2 concentration and malformed skeletogenesis was observed in both larvae. This suggests that calcification is affected by elevated
CO2 in the seawater. From these results, we conclude that increased CO2 concentration in seawater will chronically affect several marine organisms and we discuss the effects of increased CO2 on the marine carbon cycle and marine ecosystem.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
40.
Yuji Watanabe Atsushi Yamaguchi Hiroshi Ishida Takashi Harimoto Shinya Suzuki Yoshio Sekido Tsutomu Ikeda Yoshihisa Shirayama Masayuki Mac Takahashi Takashi Ohsumi Joji Ishizaka 《Journal of Oceanography》2006,62(2):185-196
The first CO2 exposure experiments on several species of pelagic copepods inhabiting surface and deep layers in the western North Pacific
were conducted. Living organisms were collected from two layers between the surface and 1,500 m between latitudes of 11 and
44°N, and they were exposed aboard ship to various pCO2 up to about 98,000 μatm. Mortality of copepods from both shallow and deep layers in subarctic to subtropical regions increased with increasing
pCO2 and exposure time. Deep-living copepods showed higher tolerance to pCO2 than shallow-living copepods. Furthermore, deep-living copepods from subarctic and transitional regions had higher tolerances
than the subtropical copepods. The higher tolerances of the deep-living copepods from subarctic and transitional regions may
be due to the adaptation to the natural pCO2 conditions in the subarctic ocean. 相似文献