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171.
A ground‐based gamma‐ray survey has been performed in the area close to El‐Ramlah village, southwestern Sinai, Egypt, using a GS‐512 spectrometer. The main objective of this survey was to delineate radioactive anomalies within the surface of the study area and to identify the environmental effects of natural radioelements on the new inhabitants, Bedouins, who live in the recently built village in this region of the Sinai Peninsula. The results show that the maximum radioactivity of the total count component (T.C.) was about 15.7Ur at the northern part of the study area. The average radioelements concentration were 0.4% for potassium, 1.6 ppm for equivalent uranium and 4.5 ppm for equivalent thorium. To identify and map the environmental effects of the concentration of these radioelements on El‐Ramlah village, measurements of potassium (K%), equivalent uranium (eU) and equivalent thorium (eTh) were converted into an equivalent dose rate. The results illustrate that, the levels of effective dose rate of the natural radioactivity of the area of study remains in the safe range without any harm to living organisms, and it stays within the maximum permissible radiation dose rate (1.0 mSv y?1) recommended by the International Commission of Radiological Protection.  相似文献   
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The potential impact of climate change on Astragalus gossypinus in Central Iran based on grid map 2.5 arc min was analyzed. A stratified sampling was applied through a geographic information system to pick up 587 sample sites (prevalence 0.39). For each sampling site, the presence or absence of given species together with environmental variables was recorded. Two novel statistical techniques, logistic regression tree (LRT) and nonparametric multiplicative regression (NPMR), were used to examine environmental variables related to the current species distribution. Using these models, maps of current potential distribution and potential distribution for a climatic change scenario (2CO2) were generated. Both statistical techniques produced strong and useful models, but NPMR identified a much smaller subset of relevant predictor variables. The model demonstrated that the occurrence of A. gossypinus is highly probable when the precipitation of the wettest month is between 30 and 50 mm and the mean temperature of the wettest quarter is between ?2 and +4 °C, but much lower outside this range. Under double-CO2 climatic scenario, predicting a moister and slightly warmer climate in Central Iran, A. gossypinus is expected to move north-eastwards with a decreasing area of distribution.  相似文献   
174.
Seismic risk assessment of the 3rd Azerbaijan gas pipeline in Iran   总被引:1,自引:1,他引:0  
A comprehensive seismic risk assessment has been performed for the existing route of the 3rd Azerbaijan natural gas buried pipeline in Iran. The major active seismic sources along the pipeline were identified and the geometrical parameters as well as the seismicity rates were determined. The seismic hazard assessment of the ground vibrations along the pipeline was performed in the framework of the Probabilistic Seismic Hazard Analysis using the CRISIS 2007 software. All of the components of the gas pipeline along the route were identified and the corresponding fragility functions are established through the methodology described in the HAZUS guideline (HAZUS MH MR4 Technical manual 2007 Department of homeland security emergency. Preparedness and Response Directorate, FEMA). A detailed cost analyses was taken into consideration based on the expert opinions in the National Iranian Gas Company, in order to provide more practical loss model for the pipeline route. Also, a simple method is suggested in order to account for the vent gas in the total loss estimation. The spatial analysis of the hazard function layer in combination with the loss model layer, in Geographical Information System  (GIS) platform, reveal the financial consequences of different earthquake scenarios.  相似文献   
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The present study aims to explain some hydrogeological problems that are related to geological setting in two wadis: El Kallabiyyah and As Sabil East Esna. For this purpose, land magnetic, vertical electrical soundings, and two-dimensional electrical resistivity imaging profiles were measured. The lithological succession comprises Upper Cretaceous to Quaternary deposits that rest on a Precambrian basement rock. The results of the interpretation of the land magnetic measurements in wadi El Kallabiyyah represent the depth to the basement rock which ranges from 260 to 660 m and increases towards the northeast trend, but in wadi As Sabil, there is a large basin at the center of the wadi with the recorded depth to the basement reaching 1,300 m due to the effect of two normal faults (F1 and F2). The results of the interpretation of the vertical electrical sounding and two-dimensional imaging confirmed the presence of these faults in wadi As Sabil. The results of the geoelectrical measurements in wadi El Kallabiyyah represented the water-bearing layer at the third unit that consists of sands, gravels, boulders, and clays. The presence of clay will affect the potentiality of a drilled well. For wadi As Sabil, the results of geoelectrical measurements led to the lower part of the second unit which acts as a water-bearing layer that consists of sands, boulders, gravels, and clays. It can be concluded that the best site for drilling wells in wadi El Kallabiyyah is at vertical electrical sounding no.5 with a total depth of not less than 230 m. In wadi As Sabil, the drilled wells must be concentrated at the center and the downstream.  相似文献   
177.
The Nopal I uranium deposit of the Sierra Peña Blanca, Mexico, has been the focus of numerous studies because of its economic importance and its use as a natural analog for nuclear-waste disposal in volcanic tuff. Secondary uranyl minerals such as uranophane, Ca[(UO2)(SiO3OH)]2(H2O)5, and weeksite, (K,Na)2[(UO2)2(Si5O13)](H2O)3, occur in the vadose zone of the deposit and are overgrown by silica glaze. These glazes consist mainly of opal A, which contains small particles of uraninite, UO2, and weeksite. Close to a fault between brecciated volcanic rocks and welded tuff, a greenish silica glaze coats the altered breccia. Yellow silica glazes from the center of the breccia pipe and from the high-grade pile coat uranyl-silicates, predominantly uranophane and weeksite. All silica glazes are strongly zoned with respect to U and Ca, and the distribution of these elements indicates curved features and spherical particles inside the coatings. The concentrations of U and Ca correlate in the different zones and both elements inversely correlate with the concentration of Si. Zones within the silica glazes contain U and Ca in a 1:1 ratio with maximum concentrations of 0.08 and 0.15 at.% for the greenish and yellow glazes, respectively, suggesting trapping of either Ca1U1-aqueous species or -particles in the colloidal silica. X-ray photoelectron spectroscopy (XPS), Fourier-transform infra-red spectroscopy (FTIR), and oxygen-isotope ratios measured by secondary-ion mass spectrometry (SIMS) indicate higher U6+/U4+ ratios, higher proportions of Si-OH groups and lower δ18O values for the greenish silica glaze than for the yellow silica glaze. These differences in composition reflect increasing brecciation, porosity, and permeability from the center of the breccia pipe (yellow silica glaze) toward the fault (green silica glaze), where the seepage of meteoric water and Eh are higher.  相似文献   
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