Lithological Mapping in the Eastern Part of the Central Iranian Volcanic Belt Using Combined ASTER and IRS data   总被引：1，自引：0，他引：1  

Seyed Mohammad Hadi Hadigheh  Hojjatollah Ranjbar 《Journal of the Indian Society of Remote Sensing》2013,41(4):921-931

The study area is located in the eastern part of the central Iranian volcanic belt. Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) and Indian Remote Sensing Satellite (IRS ) pan images were used for applying several image classification methods for lithological mapping. ASTER visible-near infrared and shortwave infrared bands were sharpened using IRS pan image. We used classification methods such as Maximum likelihood, Spectral Angle Mapper (SAM) and Spectral Information Divergence (SID) in order to evaluate the usefulness of these methods for geological mapping. The classification results showed that MLC has the best accuracy and the classified image closely resembles the previously prepared geology map of the area.  相似文献   

Geochemical characterization and modelling of the Toarcian/Domerian porewater at the Tournemire underground research laboratory     

J. Tremosa  D. Arcos  J.M. Matray  F. Bensenouci  E.C. Gaucher  C. Tournassat  J. Hadi 《Applied Geochemistry》2012

For safety evaluation of hazardous waste repositories in clay-rocks, a thorough assessment of porewater chemistry and water–rock interactions is required. However, this objective is a challenging task due to the low hydraulic conductivity and water content of such rocks, which subsequently renders porewater sampling difficult (without inducing perturbations). For this reason, an indirect approach was developed to determine porewater composition of clay-rocks, by a geochemical model of water–rock interaction using some properties of the rock and the solution. The goal of this paper is to obtain the porewater composition of the Toarcian/Domerian argillaceous formation at Tournemire (South of France), for which a reliable model is still lacking. The following work presents a comprehensive characterization of the geochemical system of the Tournemire clay-rock, including mineralogy, petrology, mobile anions, cation exchange properties, accessible porosity and CO₂ partial pressure. Perturbation corrections from fracture water sampling were also computed. These water were found in sealed fractures (Beaucaire et al., 2008) and their radiocarbon apparent age is estimated at 20 ka. Their age together with their equilibrium situation allow considering these fracture waters as representative of the formation porewater. The model developed to calculate the Tournemire porewater composition is essentially based on cation exchange by a multi-site approach, but equilibrium with some mineral phases (calcite, quartz and pyrite) is also considered. Different exchange sites of different affinities towards cations are used, which proportions are given by the mineralogy. Exchange on illite is performed with a three-sites model, while one site is considered for smectite phases. Multi-site model results are compared with corrected fracture water data and two other models: a model only based on mineral equilibrium and a model using cation exchange on one global site. The best results were obtained with the models that take into account cation exchange and particularly with the multi-site model. The interest in considering a model with exchange sites of different affinities is particularly obvious for a satisfactory representation of the K⁺ content in solution. A dependence of K⁺ content to the amount of high affinity sites was observed, leading to an improvement of its simulation when uncertainty on mineralogical data is considered. Once validated, the multi-site model was applied at different levels of the Tournemire argillaceous formation to obtain a profile of the porewater composition.  相似文献   

Shrinkage Properties of Soft Clay Treated with Cement and Geofibers   总被引：4，自引：2，他引：2  

Behzad Fatahi  Thu Minh Le  Behnam Fatahi  Hadi Khabbaz 《Geotechnical and Geological Engineering》2013,31(5):1421-1435

In this study, effects of two types of geofibers, namely polypropylene and recycled carpet, on three dimensional shrinkage properties of cement treated kaolinite and bentonite clays are investigated. Cement treated clay specimens were prepared with cement contents of 5, 10, and 15 % by weight of dry soil for kaolinite samples, and 30, 40 and 50 % for bentonite samples. To investigate and understand the influence of different fiber types and contents, three different percentages of fiber content (i.e. 0.1, 0.2 and 0.5 % polypropylene fibers; and 0.5, 0.75 and 1 % carpet fibers) were adopted. The results of shrinkage tests on 126 cylindrical samples of cement treated clay with various cement and fiber contents were analysed to understand the relationships between these parameters and the shrinkage percentage of treated soil. Results of this study indicate that combination of cement and fiber is effective in reducing the volume change of clayey soils undergoing drying process. In the applied ranges of cement and fiber contents, the influence of cement addition on the shrinkage reduction is more significant than the addition of fibers for the treated kaolinite. However, addition of fibers in curtailing the shrinkage of bentonite clay is more significant than the cement addition.  相似文献   

Editorial     

Hadi Hajibeygi  Jan Dirk Jansen  Olwijn Leeuwenburgh  Denis Voskov 《Computational Geosciences》2017,21(5-6):833-833

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Groundwater Origin in Qanats,Chemo-Isotopic,and Hydrogeological Evidence     

Hojat Mirani Moghadam  Rahim Bagheri  Gholam Hossein Karami  Hadi Jafari 《Ground water》2020,58(5):771-776

A systematic study of the chemo-isotopic characteristics and origin of the groundwater was carried out at six major qanats in the hyper-arid Gonabad area, eastern Iran. These qanats as a sustainable groundwater extraction technology have a long history, supporting human life for more than a thousand years in this region. The Gonabad qanats are characterized by outlet electrical conductivity (EC) values of 750 to 3900 µS/cm and HCO₃-Na-Mg and Cl-Na water types. The Gonabad meteoric water line (G_nMWL) was drawn at the local scale as δ²H = 6.32×δ¹⁸O + 8.35 (with R² = 0.90). It has a lower slope and intercept than the global meteoric water line due to different water vapor sources and isotope kinetic fractionation effects during precipitation in this arid region. The altitude effects on isotopic content of precipitation data were derived as δ¹⁸O = (−0.0031 × H_(m.a.s.l))−1.3). The δ²H and δ¹⁸O isotopes signatures demonstrate a meteoric origin of the groundwater of these qanats. The shift of the qanat's water samples from the local meteoric water line (LMWL) in a dry period with higher temperatures is most probably due to evaporation during the infiltration process and water movement in qanat gallery. Based on the isotopic results and mass balance calculations, the qanats are locally recharged from an area between 2000 to 2400 m.a.s.l of nearby carbonate formations and coarse alluvial sediments. The dissolution of evaporate interlayers in Neogene deposits deteriorates the groundwater quality, especially in Baidokht qanat.  相似文献   

Expert views on biodiversity conservation in an era of climate change     

Shannon Hagerman  Hadi Dowlatabadi  Terre Satterfield  Tim McDaniels 《Global Environmental Change》2010,20(1):192-207

Adapting conservation policy to the impacts of climate change has emerged as a central and unresolved challenge. In this paper, we report on the results of 21 in-depth interviews with biodiversity and climate change adaptation experts on their views of the implications of climate change for conservation policy. We find a diversity of views across a set of topics that included: changing conservation objectives, conservation triage and its criteria, increased management interventions in protected areas, the role of uncertainty in decision-making, and evolving standards of conservation success. Notably, our findings reveal active consideration among experts with some more controversial elements of policy adaptation (including the role of disturbance in facilitating species transitions, and changing standards of conservation success), despite a comparative silence on these topics in the published literature. Implications of these findings are discussed with respect to: (a) identifying future research and integration needs and (b) providing insight into the process of policy adaptation in the context of biodiversity conservation.  相似文献   

Stabilization of tropical kaolin soil with phosphoric acid and lime   总被引：2，自引：0，他引：2  

Amin?EisazadehEmail author  Khairul?Anuar?Kassim  Hadi?Nur 《Natural Hazards》2012,61(3):931-942

Studies on the chemically stabilized soils have shown that the effectiveness of treatment is largely dependent on soil’s natural environment. In tropical kaolin soils, phosphoric acid may be used as an alternative to traditional alkaline stabilizers for improving soil properties. This research was carried out in an effort to identify the time-dependent soil-stabilizer reactions. Data for the study of characterization of treated samples were obtained from X-ray diffractometry, energy dispersive X-ray spectrometry, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and leaching analysis. Based on the collected data, the kaolinite mineral with pH-dependent structural properties showed slightly different behavior both in basic and in acidic mediums. Also, it was found that the chemical stabilizers preferentially attacked the alumina surface of the clay particles. Therefore, it was rational to suggest that with respect to lime and phosphoric acid treatment, aluminate hydrate compounds are more likely to be formed.  相似文献   

Cation Exchange Capacity of Phosphoric Acid and Lime Stabilized Montmorillonitic and Kaolinitic Soils     

Amin Eisazadeh  Khairul Anuar Kassim  Hadi Nur 《Geotechnical and Geological Engineering》2012,30(6):1435-1440

Studies on the chemically stabilized soils have shown that the effectiveness of treatment is largely dependent on soil??s natural environment. In this research, the time-dependent changes induced in permanent cation exchange capacity of lime and phosphoric acid treated soils, comprised mainly of montmorillonite and kaolinite minerals, were investigated. Also, in order to study the relationship between the exchange capacity and acidity/alkalinity of pore water, pH measurements were performed on cured samples. Based on the collected data, it was found that the pH of stabilized soils showed a tendency for reaching soil??s natural pH with increasing curing time. In addition, the increase in number of broken bonds around the edges of soil particles and also the formation of cementitious compounds that acquired negative charges contributed to achieving higher CEC_p values at longer curing periods. Nevertheless, the kaolinite mineral with pH-dependent structural properties, showed a rather limited behavior in the acidic medium. From engineering point of view, the lime treated samples revealed the highest degree of improvement with an approximately ten-fold strength increase in comparison to the natural soil over an 8?months curing period.  相似文献   

Application of Fuzzy Set Theory to Rock Engineering Classification Systems: An Illustration of the Rock Mass Excavability Index   总被引：1，自引：0，他引：1  

Jafar Khademi Hamidi  Kourosh Shahriar  Bahram Rezai  Hadi Bejari 《Rock Mechanics and Rock Engineering》2010,43(3):335-350

The characterization of rock masses is one of the integral aspects of rock engineering. Over the years, many classification systems have been developed for characterization and design purposes in mining and civil engineering practices. However, the strength and weak points of such rating-based classifications have always been questionable. Such classification systems assign quantifiable values to predefined classified geotechnical parameters of rock mass. This results in subjective uncertainties, leading to the misuse of such classifications in practical applications. Fuzzy set theory is an effective tool to overcome such uncertainties by using membership functions and an inference system. This study illustrates the potential application of fuzzy set theory in assisting engineers in the rock engineering decision processes for which subjectivity plays an important role. So, the basic principles of fuzzy set theory are described and then it was applied to rock mass excavability (RME) classification to verify the applicability of fuzzy rock engineering classifications. It was concluded that fuzzy set theory has an acceptable reliability to be employed for all rock engineering classification systems.  相似文献   

Isolates of Staphylococcus aureus and saprophyticus resistant to antimicrobials isolated from the Lebanese aquatic environment   总被引：5，自引：0，他引：5  

Harakeh S  Yassine H  Hajjar S  El-Fadel M 《Marine pollution bulletin》2006,52(8):912-919

The indiscriminate use of antimicrobials especially in developing countries has evoked serious bacterial resistance and led to the emergence of new and highly resistant strains of bacteria to commonly used antimicrobials. In Lebanon, pollution levels and bacterial infections are increasing at a high rate as a result of inadequate control measures to limit untreated effluent discharges into the sea or freshwater resources. The aim of this study was to isolate and molecularly characterize various Staphylococcus strains isolated from sea water, fresh water, sediments, and crab samples collected from representative communities along the coast of Lebanon. The results on the antimicrobial resistance indicated that the level of resistance of Staphylococcus aureus varied with various antimicrobials tested. The resistance patterns ranged between 45% in freshwater isolates and 54.8% in seawater ones. Fifty one percent of the tested isolates have shown resistance to at least one of the five tested antimicrobials; with seawater isolates exhibiting the highest rates of antimicrobial resistance.  相似文献