The impact of halite dissolution of salt diapirs on surface and ground water under climate change,South-Central Iran   总被引：1，自引：0，他引：1  

Mostafa Naderi  Ezzat Raeisi  Mehdi Zarei 《Environmental Earth Sciences》2016,75(8):708

  相似文献   

Investigation of current and future potential distribution of <Emphasis Type="Italic">Astragalus gossypinus</Emphasis> in Central Iran using species distribution modelling     

Mostafa Tarkesh  Gottfried Jetschke 《Arabian Journal of Geosciences》2016,9(1):80

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   

Comparative approach of three popular intrinsic vulnerability methods: case of the Beni Amir groundwater (Morocco)   总被引：1，自引：0，他引：1  

Najat Knouz  Abdelghani Boudhar  El Mostafa Bachaoui  Charkaoui Saadi 《Arabian Journal of Geosciences》2018,11(11):281

The study of the intrinsic vulnerability of groundwater resources to pollution is an effective tool to control their quality degradation and contribute to their protection. It is used to delimit the vulnerable zones which do not withstand a large flow of pollutants introduced from the soil surface. Three methods of assessing the intrinsic vulnerability of groundwater: DRASTIC (Depth to water table, Recharge, Aquifer, Soil type, Topography, Impact of zone vadose, Hydraulic conductivity), DRSTI, and GOD (Groundwater occurrence, Overall aquifer class and Depth of water table) coupled with a geographic information system (GIS) are applied to the groundwater of Beni Amir, and they are compared in order to adopt the method which better characterizes the vulnerability of the aquifer to pollution. The validation of this application was made by measurements of the nitrate levels in the aquifer. Because the pollution of groundwater, in this plain, is a direct consequence of agricultural activities characterized by an intensive fertilizer application. The results clearly show that the rate of the coincidence, between the measured nitrate concentrations and the different classes of vulnerability of three methods, is 81.81, 54.54, 72.72, and 27.27%, respectively, for methods DRASTIC (classification of Engel et al. (Int Assoc Hydrol Sci Publi 235:521–526, 1996)), DRASTIC (classifications of Aller et al. (1987)), DRSTI, and GOD. Of this rate of coincidences, the DRASTIC method, with the classification of Engel et al. (Int Assoc Hydrol Sci Publi 235:521–526, 1996), allows a finer assessment and turns out the most representative of the study area.  相似文献   

Improving the existing roadway tunnels capacity by adding new tunnels—a structural approach     

Mostafa Zaki AbdElrehim  Mohamed A. Eid  Osama Moshref 《Arabian Journal of Geosciences》2018,11(5):89

The roadway tunnel is considered a good solution for the success of modern roadway networks. It can help to overcome possible traffic congestion and considerably reduce journey time. The continuous growth of traffic volumes leads to increase congestion and decrease safety. This leads to the need for extra tunnel space. The extra tunnel space can be achieved either by the widening of the existing tunnel or by adding a new one. The choice of the suitable method is dependent on many factors like tunnels alignment, site conditions, construction method, tunnel operation, risk assessment…etc. The current research investigates the second alternative through a specific case study as an example. The method comprises adding two new tunnels to an existing twin roadway tunnels. The investigated problem considers the new tunnels to be added vertically or horizontally. The influence of the new tunnel construction on the existing tunnels is investigated considering both the variation of relative position and spacing distance in a parametric study context. Several numerical models are employed to check the construction sequence and the tunnelling safety. These models are used to evaluate the induced stresses in surrounding ground for two different soil types, straining actions in tunnels’ liner and deformations of both ground and liner. The result demonstration shows how to find out the minimum practical and safe spacing distance between the driven new tunnels and the existing ones without the need for the relatively expensive soil strengthening techniques.  相似文献   

Uranium-rich opal from the Nopal I uranium deposit, Peña Blanca, Mexico: Evidence for the uptake and retardation of radionuclides     

Michael Schindler  Mostafa Fayek  Frank C. Hawthorne 《Geochimica et cosmochimica acta》2010,74(1):187-202

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   

Use of Solute Chemistry and Isotopes to Identify Sources of Ground-Water Recharge in the Nile Aquifer System, Upper Egypt     

Mostafa A. Awad  Nahed E. El Arabi  Mokhtar S. Hamza 《Ground water》1997,35(2):223-228

  相似文献   

Exact and hybrid-element solutions for the vibration of a thin elastic structure seated on the sea floor     

Chiang C. Mei  Mostafa A. Foda  P. Tong 《Applied Ocean Research》1979,1(2):79-88

Exact analytical solutions are derived for simple elastic structures vibrating in water. Linear acoustic and beam theories are used to treat several cases some of which have been studied by more approximate methods before. A hybrid element method which is based on a localized variational principle is demonstrated numerically for a beam-dam; its theoretical bases is then generalized for arbitrary two-dimensional elastic structure. Foundation compliance is not included.  相似文献   

Synergie entre la télédétection multispectrale et les données de terrain pour la conception d'un nouveau modèle géodynamique d'ouverture du bassin paléozoïque des Jebilet centrales (Maroc)     

Abderrazak El Harti  Abderrazak Bannari  El Mostafa Bachaoui  El Mostafa Aarab  Guillaume Girouard  Abderrahmen El Ghmari 《Comptes Rendus Geoscience》2004,336(14):1311-1320

The geodynamic model of the Palaeozoic basin opening of central Jebilet has been unknown before this study in spite of the abundance in the geological studies carried out in the studied sector using conventional methods. This is due to the scarcity of the key beds and synsedimentary structures. Using the synergy between the image data of the Landsat satellite TM sensor and the ground data, we have highlighted, herein, new structural data allowing the design of a new model of the Palaeozoic basin opening of central Jebilet. This opening could have been made according to dextral submeridian transverse faults with the individualization of subequatorial normal faults. To cite this article: A. El Harti et al., C. R. Geoscience 336 (2004).  相似文献   

Pipeline breakout from sea floor under wave action     

Mostafa A. Foda 《Applied Ocean Research》1985,7(2):79-84

The vertical stability of a submarine pipeline laid half-buried on the sea floor under wave action is studied. As the wave-induced lifting force acts to detach the pipe from the sea floor, mud suction resistance will be developing at pipe-soil interface, acting to hold the pipe in place. This couples the pipe equilibrium with the seabed response which is modelled as a poroelastic media, following the formulation of Biot. Conditions for pipe detachment or breakout from the sea floor are investigated for typical seawave, pipe, and seabed parameters. A general power law will describe the slow quasistatic breakout of the pipe. In the case when the forcing wave period is much shorter than the quasistatic breakout time, the response function of the coupled pipe-seabed system will involve weak nonlinear terms of higher harmonics. The possibilities for resonating the system in such case are examined by including the inertia of the pipe in the analysis.  相似文献   

Combining visual and geochemical analyses to source chert on Southern Baffin Island,Arctic Canada     

S. Brooke Milne  Anne Hamilton  Mostafa Fayek 《Geoarchaeology》2009,24(4):429-449

A combined methodological approach using visual and geochemical methods is introduced and preliminary results of a study illustrating its effectiveness to determine chert source provenance are presented. This study focuses on lithic debitage and raw chert samples collected from the interior of southern Baffin Island, Arctic Canada. Chert is abundant throughout this region yet it occurs as small, scattered surface nodules that are highly variable in color. Prior to this study, little was known about the provenance of this local toolstone and whether it derived from local outcrops, glacial till sheets, or both. Given the pronounced variability exhibited by this chert, we use individual attribute analysis and petrography to impose some kind of analytical order upon an otherwise random aggregation of rocks. Thereafter, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry are used to test the validity of these color categories to determine from how many geochemically distinct sources they derive. Using a standard that measures Al to a ratio of Ga/Zr, our results indicate that all of the raw chert samples derive from a single local source, while the debitage derives from four different sources, including the one that is local. We are confident that this combined methodological approach can be applied in other regions where chert variability is pronounced and source provenance is unknown. © 2009 Wiley Periodicals, Inc.  相似文献