Natural and artificial recharge investigation in the Zéroud Basin,Central Tunisia: impact of Sidi Saad Dam storage   总被引：1，自引：0，他引：1  

Sarra Bel Hadj Salem  Najiba Chkir  Kamel Zouari  Anne Laure Cognard-Plancq  Vincent Valles  Vincent Marc 《Environmental Earth Sciences》2012,66(4):1099-1110

Hydrochemical and isotopic data of waters from the Zéroud aquifer have been used to potentially provide a means for locating occurrences and to trace movements of a variety of natural and anthropogenic recharge waters in the Zéroud Basin, Central Tunisia. Geochemical data have been measured during the dam water release, from May to September 2005, with a sampling time step of 15 days. An implication of dam water has been demonstrated that is noticeable up along the main flow path to a distance of 10 km far from the injection site. Environmental isotopes ²H, ¹⁸O and ³H of water molecule were studied to investigate the effect of dam water on the hydrological system, and an isotope balance was established to compute the contribution of water storage component in groundwater. Based on isotopic mass balance, we assess that an average of 13% of total groundwater in the upper aquifer came from dam water storage. Three distinctive recharge waters in the aquifer can be determined. Water from local rainfall (pre-dam Zéroud River) that infiltrated into the boundaries of the Draa Affane Mountain was easily distinguished from the water influenced by anthropogenic recharge located in the Zéroud right rivulet. Distinguishable isotopic signatures of native wadi Zéroud recharge due to “recent lineal recharge” through the riverbed were also identified.  相似文献   

Systematic development of a new hysteretic damper based on torsional yielding: part I—design and development          下载免费PDF全文

Ali Salem Milani  Murat Dicleli 《地震工程与结构动力学》2016,45(6):845-867

Analytical and experimental studies into the behavior of a new hysteretic damper, designed for seismic protection of structures is presented in two papers. Although the subject matter of the papers is a specific system, they are also intended as an illustration of practical application of diverse engineering tools in systematic development of an anti‐seismic product. The Multi‐directional Torsional Hysteretic Damper (MTHD) is a recently patented invention in which a symmetrical arrangement of identical cylindrical steel energy dissipaters is configured to yield in torsion while the structure experiences planar movements due to earthquake shakings. The device has gone through many stages of design refinement, prototype verification tests and development of design guidelines and computer codes to facilitate its implementation in practice. The first of this two‐part paper summarizes the development stages of the new system, conceptual and analytical. The experimental phase of the research is the focus of the accompanying paper. The new device has certain desirable properties. Notably, it is characterized by a variable and controllable‐via‐design or adaptive post‐elastic stiffness. This feature gives the isolated structure the capability to evade the dominant period of the ground motion leading to reduced displacements while having force levels comparable to regular bilinear isolation systems. The device has already been applied to four major bridges. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Systematic development of a new hysteretic damper based on torsional yielding: part II—experimental phase          下载免费PDF全文

Ali Salem Milani  Murat Dicleli 《地震工程与结构动力学》2016,45(5):779-796

This paper reports on experimental studies carried out on a 200 kN, 120 mm‐capacity prototype of the newly developed multidirectional torsional hysteretic damper for seismic protection of structures. The main goal of the experiments is to test the validity of the theory developed in a companion paper and to evaluate the low‐cycle fatigue performance of the energy dissipaters of the damper. Because the design and configuration of the damper allow easy replacement of the energy dissipaters, four sets of energy dissipaters were produced out of S355J2 + N, C45 (two sets), and 42CrMo4 + QT steel grades. Force–displacement response of the multidirectional torsional hysteretic damper is studied through fully reversed cyclic quasi‐static displacement‐controlled tests that were carried out in compliance with EN 15129. Following the verification tests, with the aim of studying fatigue and fracture behavior of the cylindrical energy dissipaters of the device, certain numbers of them were subjected to further cyclic tests up to failure, and observations on their fatigue/fracture behavior are reported. The experimental verification test results proved the validity of the developed theory and component design assumptions presented in a companion paper. Furthermore, the energy dissipaters exhibited excellent torsional low‐cycle fatigue performance with number of cycles to failure reaching 118 at a maximum shear strain of 8% for S355J2 + N steel grade. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Assessing groundwater vulnerability to nitrate pollution using statistical approaches: a case study of Sidi Bouzid shallow aquifer,Central Tunisia     

Ikram Jmal  Bachaer Ayed  Emna Boughariou  Nabila Allouche  Salwa Saidi  Monji Hamdi  Salem Bouri 《Arabian Journal of Geosciences》2017,10(16):364

The study region comprises the Sidi Bouzid shallow aquifer, which is located in the western part of Central Tunisia. It is mainly occupied by agricultural land with intensive use of chemical fertilizers especially nitrates. For this reason, nitrate measurement was performed in 38 water samples to evaluate and calibrate the obtained models. Several environmental parameters were analyzed using groundwater nitrate concentrations, and different statistical approaches were applied to assess and validate the groundwater vulnerability to nitrate pollution in the Sidi Bouzid shallow aquifer. Multiple linear regression (MLR), analyses of covariance (ANCOVA), and logistic regression (LR) were carried out for studying the nitrate effects on groundwater pollution. Statistical analyses were used to identify major environmental factors that control the groundwater nitrate concentration in this region. Correlation and statistical analyses were conducted to examine the relationship between the nitrate (dependent variable) and various environmental variables (independent variables). All methods show that “groundwater depth” and “land use” parameters are statistically significant at 95% level of confidence. Groundwater vulnerability map was obtained by overlaying these two thematic layers which were obtained in the GIS environment. It shows that the high vulnerability area coincides with the likelihood that nitrate concentration exceeds 24.5 mg/l in groundwater. The relationship between the groundwater vulnerability classes and the nitrate concentrations provides satisfactory results; it showed an Eta-squared correlation coefficient of 64%. So, the groundwater vulnerability map can be used as a synthetic document for realistic management of groundwater quality.  相似文献   

Groundwater vulnerability and risk mapping of the Hajeb-jelma aquifer (Central Tunisia) using a GIS-based DRASTIC model   总被引：7，自引：2，他引：5  

Salwa Saidi  Salem Bouri  Hamed Ben Dhia 《Environmental Earth Sciences》2010,59(7):1579-1588

The aim of this study is to elaborate a synthetic document for the assessment of groundwater vulnerability to pollution in the Hajeb-Jelma aquifer. The specific object is to incorporate the Geographical Information System (GIS) to generate groundwater vulnerability and risk maps with DRASTIC model. Indeed, GIS could help to make the results of a complicated model more clear through visual representation, providing an applicable tool for decision makers. The vulnerability map of Hajeb-Jelma watershed shows three classes: moderate, high and very high depending on the intrinsic properties. The risk map shows a very high risk dependant on hydrogeological characteristics, land use and human impacts in major part of the Hajeb-Jelma region. These maps could serve as a scientific basis for sustainable land use planning and groundwater management in the Hajeb-Jelma region.  相似文献   

Structural Setting of Northern Tunisia Insights from Gravity Data Analysis Jendouba Case Study     

Imen Hamdi Nasr  Adnen Amiri  Mohamed Hédi Inoubli  Abdelhmid Ben Salem  AbdelHak Chaqui  Said Tlig 《Pure and Applied Geophysics》2011,168(10):1835-1849

Detailed gravity data in conjunction with available surface geology are analyzed to infer the organization of the underlying structures in Jendouba area. Gravity data analysis benefits from the gravity Bouguer anomaly, upward continuations, residual distribution, derivatives and Euler deconvolved maps. The main results display a positive amplitude gravity anomaly as the response of Triassic evaporitic bodies and important NE trending features at the boundaries between the Triassic outcrops and their enveloping strata. Integration of gravity, geological and structural maps let to the identification of major structural directions and trends of the study area. It confirms some structural elements gathered from outcrops. It defines also new ones.  相似文献   

Erratum to: Properties of geothermal resources in Kebilli region, Southwestern Tunisia     

Fatma Ben Brahim  Jalila Makni  Salem Bouri  Hamed Ben Dhia 《Environmental Earth Sciences》2013,69(6):2125-2125

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Hydrochemical analysis and evaluation of groundwater quality of a Mio-Plio-Quaternary aquifer system in an arid regions: case of El Hancha, Djebeniana and El Amra regions, Tunisia   总被引：1，自引：1，他引：0  

Fatma Ben Brahim  Salem Bouri  Hafedh Khanfir 《Arabian Journal of Geosciences》2013,6(6):2089-2102

A hydrogeochemical approach has been carried out in the Mio-Plio-Quaternary aquifer system of northern Sfax to investigate the geochemical evolution, the origin of groundwaters and their circulation patterns. The groundwater samples collected from different wells seem to be dominated by sodium chloride type to sulphate chloride type. Detail analysis of chemical data including the thermodynamic calculations was used to assess that the chemical evolution of groundwater is primarily controlled by water–rock interactions. The values of sodium absorption ratio and electrical conductivity of the groundwater were plotted in the US Salinity Laboratory diagram for irrigation water. Most of the water samples in northern Sfax fall in the fields of C4S1, C4S2 and C4S3 indicating very high salinity and medium to high sodium alkalinity hazard. Thus, groundwater quality is ranging between doubtful to unsuitable for irrigation uses under normal condition, and further action for salinity control is required in remediating such problem. Principal component analysis of geochemical data used in conjunction with bivariate diagrams of major elements indicates that groundwater mineralization is mainly controlled by (1) water–rock interaction processes, (2) anthropogenic process in relation with return flow of NO₃-rich irrigation waters and (3) domestic discharges.  相似文献   

Fate of drilling waste discharges and ecological risk assessment in the Egyptian Red Sea: an aquivalence-based fuzzy analysis   总被引：2，自引：2，他引：0  

Ahmad Agwa  Heba Leheta  Ahmed Salem  Rehan Sadiq 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(1):169-181

Egypt is located in the Northeast of Africa where oil and gas (O&G) are produced offshore from the Gulf of Suez and the Southeast part of the Mediterranean. The O&G production in Egypt is distributed as follows: 70% from Gulf of Suez, 16% from Western desert, 8% from the Sinai Peninsula and 6% from Eastern desert. Past O&G activities, refining and transport have resulted in chronic pollution in Egyptian offshore and numerous environmental programs have been initiated to protect new development areas from the environmental impacts. The offshore drilling process uses drilling fluids (mud) and generates waste fluids and cuttings, which could be the largest discharges going into the receiving water bodies. There are several options to manage offshore drilling wastes: offshore discharge, offshore down-hole injection and onshore disposal. Water-based drilling fluids (WBF) are commonly employed for drilling in Egyptian offshore because of their expected environmental benign behavior. The main objective of this paper is to develop a methodology to determine the fate of heavy metals associated with WBF drilling waste in the marine environment and estimate the associated ecological risks. Proposed contaminant fate model is based on an aquivalence approach, which has been integrated with fuzzy-based analysis to study the uncertainties. This research concluded that the impacts of heavy metals associated with the drilling waste discharges in the receiving waters are minimal.  相似文献   

Methodology for comparing two carrier phase tracking techniques   总被引：1，自引：0，他引：1  

Dina Reda Salem  Cillian O’Driscoll  Gérard Lachapelle 《GPS Solutions》2012,16(2):197-207

The carrier phase tracking loop is the primary focus of the current work. In particular, two carrier phase tracking techniques are compared, the standard phase tracking loop, i.e., the phase lock loop (PLL), and the extended Kalman filter (EKF) tracking loop. In order to compare these two different techniques and taking into consideration the different models adopted in each, it is important to bring them to one common ground. In order to accomplish this, the equivalent PLL for a given EKF has to be determined in terms of steady-state response to both thermal noise and signal dynamics. A novel method for experimentally calculating the equivalent bandwidth of the EKF is presented and used to evaluate the performance of the equivalent PLL. Results are shown for both the L1 and L5 signals. Even though the two loops are designed to track equivalent dynamics and to have equivalent carrier phase standard deviations, the EKF outperforms the equivalent PLL in terms of both the transient response and sensitivity.  相似文献