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A. Wahab Khair 《Geotechnical and Geological Engineering》1985,3(4):243-259
Summary This paper presents an analysis of causes of bump in a deep coal mine. The analysis consists of in-mine measurement determination, analysis of physical and mechanical properties of mine materials and simulation of mine layout and mining sequence. Major factors contributing to the causes of bump have been reviewed and those that are related to this case have been identified and simulated analytically using a three-dimensional finite element method. 相似文献
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Based on geomorphologic and hydrogeologic characteristics of its territory, Lebanon is divided into three provinces: the West Lebanon province, the Bekaa province, and the East Anti-Lebanon province. These provinces are subdivided into smaller hydrogeologic units, the basins and subbasins. Significant features used in the subdivision are faults, relief, anticlinal axes, river channels, and water divides. Recharge to groundwater is a percentage of the intake area, the percipitation rate over this area, and the infiltration rate of outcropping rocks. The amounts of recharged water over the three provinces are 1609, 914, and 19 Mm3, respectively. Discharge is surface water from springs and water wells along the Lebanese coast. The discharge from the Lebanese rivers exceeds 3700 Mm3/year, an appreciable amount of which comes from natural springs. The quantity of groundwater pumped by wells or flowing into neighboring countries and to the sea as submarine springs, may exceed 800 Mm3/year. 相似文献
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Fluoride and arsenic hydrogeochemistry of groundwater at Yuncheng basin,Northern China 总被引：1，自引：0，他引：1
Anas M. Khair Chengcheng Li Qinhong Hu Xubo Gao Yanxin Wanga 《Geochemistry International》2014,52(10):868-881
High fluoride and arsenic concentrations in groundwater have led to serious health problems to local inhabitants at Yuncheng basin, Northern China. In this study, groundwater with high fluoride and arsenic concentration at Yuncheng basin was investigated. A majority of the samples (over 60%) belong to HCO3 type water. The predominant water type for the shallow groundwater collected from southern and eastern mountain areas was Ca/Mg-Ca-HCO3 types. For the shallow groundwater from flow through and discharge area it is Na-HCO3/SO4-Cl/SO4/Cl type. The predominant water type for the intermediate and deep groundwater is of Na/Ca/Mg-Ca-HCO3 type. According to our field investigation, fluoride concentration in groundwater ranges between 0.31 and 14.2 mg/L, and arsenic concentration ranges between 0.243 and 153.7 μg/L. Out of seventy collected groundwater samples, there are 31 samples that exceed the World Health Organization (WHO) standard of 1.5 mg/L for fluoride, and 15 samples exceeds the WHO standard of 10 μg/L for arsenic. Over 40% of high fluoride and arsenic groundwater are related to the Na-HCO3 type water, and the other fifty percent associated with Na-SO4-Cl/HCO3-SO4-Cl type water; little relation was found in calcium bicarbonate type water. A moderate positive correlation between fluoride and arsenic with pH were found in this study. It is due to the pH-dependent adsorption characteristics of F and As onto the oxide surfaces in the sediments. The observed negative correlation between fluoride and calcium could stem from the dissolution equilibrium of fluorite. The high concentration of bicarbonate in groundwater can serve as a powerful competitor and lead to the enrichment of fluoride and arsenic in groundwater. Most of the groundwater with high fluoride or arsenic content has nitrate content about or over 10 mg/L which, together with the observed positive correlations between nitrate and fluoride/arsenic, are indicative of common source of manmade pollution and of prevailing condition of leaching in the study area. 相似文献
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The phenomenon of localized amplification of seismic waves due to subsurface irregularities has attracted the attention of seismologists and engineers for many years. In this paper we present a hybrid numerical method to investigate the ground motion amplification due to sedimentary basins. This method combines the integral representation and the finite element to solve the scattering problem due to an arbitrary cylindrical scatterer. A study is done on two shapes of valleys to show the effect of the angle of incidence, the incident wave type and the layering on the amplification of the surface displacement components by different valleys. 相似文献
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Groundwater Governance in a Water‐Starved Country: Public Policy,Farmers' Perceptions,and Drivers of Tubewell Adoption in Balochistan,Pakistan 
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下载免费PDF全文 Pakistan faces the challenge of developing sustainable groundwater policies with the main focus on groundwater management rather than groundwater development and with appropriate governance arrangement to ensure benefits continue into the future. This article investigates groundwater policy, farmers' perceptions, and drivers of tubewell (groundwater bore) adoption and proposes possible pathways for improved groundwater management for Balochistan, Pakistan. Historical groundwater policies were mainly aimed at increasing agricultural production and reducing poverty, without consideration of adverse impact on groundwater availability. These groundwater policies and governance arrangements have resulted in a massive decline in groundwater tables. Tubewell owners' rankings of the drivers of groundwater decline suggest that rapid and widespread installation of tubewells, together with uncontrolled extraction due to lack of property rights, electricity subsidy policies, and ineffective governance, are key causes of groundwater decline in Balochistan. An empirical “tubewell adoption” model confirmed that the electricity subsidy significantly influenced tubewell adoption decisions. The article proposes a more rational electricity subsidy policy for sustaining groundwater levels in the short‐run. However, in the long run a more comprehensive sustainable groundwater management policy, with strong institutional support and involvement of all stakeholders, is needed. 相似文献
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The opening of the Gulf of Aden and the Red Sea, and the collision of the Arabian plate with the jigsaw southern margin of the Anatolian plate have sheared the Sinai-Levant microplate off the NW part of the Arabian plate, and created the left-lateral Dead Sea (Levant) transform fault. The structural setting of the northern Levant region, particularly Lebanon and the Palmyrides, has been complicated by detachments along incompetent evaporitic horizons, roughly separating the post-Triassic succession from the underlying crustal material. The interpretation of the multiple source Werner deconvolution (MSWD) estimates of Bouguer gravity profiles, which were separately calculated for Syria and Lebanon, integrated with the available geological and geophysical results leads to the following interpretations: (1) the crust of Syria thickens southeastwards from approximately 32 km under the Al-Ghab Graben to >36 km under the Aleppo high, the Palmyride fold belt and the Rutbah high; (2) the lower-crustal (basaltic) layer thickens northwestwards from the hinterland to the Al-Ghab graben at the expense of the overlying andesitic layer; (3) the Mid-Beqa'a fault is delineated by the MSWD estimates in Lebanon and its NE extension in Syria; (4) the Phanerozoic section in the southwesternmost parts of the Palmyrides is ∼ 13 km thick, and the shortening there could exceed 30 km; (5) the Palmyride fold belt, and the Serghaya and Mid-Beqa'a faults could have accounted for about 70 km of the 105 km left-lateral displacement along the southern segment of the Dead Sea transform fault system, without transmission to the Syrian (northern) segment of the fault system; (6) the splitting of the Dead Sea transform fault in the Kuleh Depression into the Serghaya. Mid-Beqa'a, Yammouneh and Roum faults could be explained by the rotation of the detached post-Triassic succession over a stable deep left-lateral fracture of the Dead Sea fault in the underlying crustal material. 相似文献
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Julie Pariseau Richard Saint-Louis Maryse Delaporte Mohammed Abo El Khair Réjean Tremblay Emilien Pelletier 《Marine pollution bulletin》2009,58(4):503-514
The aetiology of haemic neoplasia (HN) is unknown, so far but many causative factors are suggested such as viral, pollution and genetics. The aim of this study was to determine if, under chronic exposure, two major pesticides (chlorothalonil and mancozeb) which are used in potato production could induce HN in soft-shell clams (Mya arenaria). Short-term experiments with acute exposure were also performed. Clams were collected from an epizootic site (North River, PEI) and from a site free of the disease (Magdalen Islands, Quebec). The tetraploid level of haemocytes was assessed by flow cytometry for each clam to determine the HN status. The bioaccumulation of pesticides in tissues was quantified by gas chromatography/mass spectrometry (GC/MS) for chlorothalonil while mancozeb and manganese were quantified by inductively coupled plasma-mass spectrometer (ICP/MS). Long term exposure to fungicide Bravo 500® did not induce high tetraploid levels on negative calm from North River and the analysis of the digestive gland and the mantle did not reveal any detectable level of chlorothalonil. In the Manzate 200 DF®, some clams revealed high level of tetraploid cells but no difference were observed between the treatments and the control. The analysis of the digestive gland and the mantle for manganese did not highlight any significant difference in tissue concentration (p = 0.05). For the acute exposure, chlorothalonil analysis showed that the active ingredient is distributed between four chlorinated compounds: 99.5% for chlorothalonil isomers, 0.4% for pentachlorothalonil and 0.1% for trichlorothalonil isomers. For a 72 h experiment, the accumulation was within 4 h; the higher tissue concentration of chlorothalonil was 59.2 μg g−1 in the mantle after 48 h, following by a decrease to an undetectable level at the end. For the manganese, the accumulation was detected after 4 h; the higher tissue concentration was 48.8 μg g−1 in the mantle after 24 h and, over the following 48 h, the accumulation decreased until the end of the trial. Based on the data, the accumulation of these fungicides seems to be transitory. Chlorothalonil and mancozeb are both oxidative-stress promoters and could have induced cell dysfunction while in the tissue. Study on the effect of these fungicides on the p53 protein system is an example of strategy that would provide information on cellular events promoting neoplasia. 相似文献