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Soil characteristics and plant distribution in saline wetlands of Oued Righ, northeastern Algeria

Journal of Arid Land 2016年第6期8卷 948-959页

作者： Naima KOULL abdelmadjid chehma Division of Desertification Surveillance Scientific and Technical Research Center of Arid Areas Touggourt 30200 Algeria Saharan Bio-resources Laboratory Safeguarding and Valorization Kasdi Merbah University of Ouargla Ouargla 30000 Algeria

Saline wetlands are rare ecosystems in Saharan areas, which are important for conservation of many endemic and rare plant species. In this study, we investigated five saline wetland sites of the Oued Righ region, located in the northeastern Algeria, to determine the environmental factors controlling the composition and distribution of plant communities. We established a total of 20 transects to measure the vegetation parameters （density and cover） and soil characteristics （electrical conductivity, moisture, pH, CaSO4, CaCO3, organic matter, Na＋, K＋, Mg2＋, Ca2＋, SO42 , CI-, NO3- and HCO3-）. A total of 17 plant species belonging to seven families were identified. The natural vegetation was composed of halophytic and hydro-halophytic plant communities, presented specially by the species of Amaranthaceae family. Soils in the studied wetlands were moist, gypsiferous, alkaline, salty to very salty with dominance of chloride and calcium. Results of the Canonical Correspondence Analysis （CCA） showed that community structure and species distribution patterns of vegetation were mainly dependent on soil characteristics, mainly being soil salinity （CaSO4, K＋, Ca2＋ and CI-） and moisture. The distribution of plant species was found to follow a specific zonal pattern. Halocnemum strobilaceum was observed to grow in highly salt-affected soils, thus being the more salt-tolerant species. Phragmites communis plants were widely distributed in the study area with a high density at the edges of accumulated water body. Juncus maritimus, Tamarix gallica and Saficornia fructicosa grew in soils that are partially or completely flooded in winter. Suaeda fructicosa, Traganum nudatum, Arthrocnemum glaucum, Aeluropus littoralis, Cressa cretica and Cynodon dactylon were distributed in salty and moist soils away from the open water body. Plants of Zygophyllum album, Limonastrirum guyonianum, Cornulaca monacantha, Cistanche tinctoria, Mollugo nudicaulis and Sonchus maritimus were found in soils wit

关键词： saline wetlands soil properties vegetation composition Sahara Algeria

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The Contribution of the Dromedary in the Spontaneous Plant Seeds Transfer in the Northern Algerian Sahara

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Journal of Life Sciences 2012年第3期6卷 300-303页

作者： Trabelsi Hafida Senoussi Abdelhakim chehma abdelmadjid Faye Bernard Laboratoire de Bio-ressources Sahariennes Preservation et Valorisation Universite Kasdi Merbah Ouargla 30000 Algerie CIRAD-ES Montpellier Cedex 34398 France

The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia （Northern Algeria Sahara）, since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces.

关键词： Dromedary seeds endozoochory Saharan rangelands Gharda'fa.

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Mechanical and magneto-electronic properties of europium lanthanide-based cubic perovskites EuYO_(3)(Y=Cr, Mn, Fe): An ab initio study

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Journal of Rare Earths 2024年第3期42卷 562-569,I0005页

作者： Hayat Ullah Azra Sarwar Sajad Ali Rabah Khenata abdelmadjid Bouhemadou Saad Bin-Omran Department of Physics Women University of Azad Jammu&Kashmir Bagh 10250Pakistan Department of Physics Abdul Wali Khan UniversityMardan23200KPPakistan LPQ3M Laboratory Institute of Science and TechnologyUniversity of Mascara29000MascaraAlgeria Laboratory for Developing New Materials and Their Characterization Farhat Abbas University Setif l19000SetifAlgeria Department of Physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh11451Saudi Arabia

Computational calculations using density functional theory(DFT) were performed for the first time using the full potential linearized augmented plane wave plus local orbital method(FP-LAPW + LO) to determine the structural, elastic, electronic and magnetic properties of europium-based cubic perovskites EuYO_(3)(Y=Cr, Mn, Fe). The exchange correlation potentials of GGA along with some analytical methods were adopted for the computation of structural and elastic properties. Moreover, the GGA + U formalism was also added for obtaining more precise electronic and magnetic properties, particularly to address the Eu-4f and Y-3d orientations in the spin-polarized double cell symmetry. The observed lattice parameters of these compounds are consistent with experiment. The observed bulk moduli predict that EuCrO_(3) is harder and less compressible than EuMnO_(3) and EuFeO_(3). The calculated tolerance factors of these compounds are within the cubic symmetry range. Our computed critical radius of EuCrO_(3) shows that EuCrO_(3) has a larger migration energy. Based on their elastic properties, these compounds are ductile in nature. We also computed the thermal properties of these compounds. The band structures and density of states show that these compounds are metallic in character. The lowest ground state energy and magnetic moments of these compounds expose their ferromagnetic nature. The metallic nature and strong ferromagnetism of these compounds make them promising applicants for application in spintronic.

关键词： Perovskites GGA+U Elastic constants Band structure Magnetic moments Rare earths

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Design of Photonic Crystal Triplexer with Core-Shell Rod Defects

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Chinese Physics Letters 2015年第5期32卷 63-65页

作者： Labbani Amel Benghalia abdelmadjid Laboratory of Hyperfrequency and Semiconductors(L.H.S.) Department of ElectronicsFaculty of Technology and SciencesUniversity Mentouri Constantine 1

We investigate an optical compact triplexer based on two photonic crystal waveguides and resonant cavities. For performing wavelength selection, we use three core-shell rods as the resonant cavities. The core rods are created by introducing air holes in the center of the silicon rods. By varying the radii of the air holes, three specific wavelengths 1.31, 1.49 and 1.55μm can be obtained. This structure is designed and its performance is verified by the finite-difference time-domain method, which is highly suitable for photonic integrated circuits （PICs）. The average output transmission efficiency and quality factor are more than 98.85% and 560, respectively. The mean value of the crosstalk between output channels is about -36.49 dB. The present device is extremely compact with total size 96.24μm2, which is suitable for PICs and can be utilized in the fiber-to-the-home system.

关键词： length Design of Photonic Crystal Triplexer with Core-Shell Rod Defects

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Synthesis of Some New 1,4-Dihydropyridine Derivatives through a Facile One-pot Hantzsch Condensation Catalyzed by Triethylamine

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Chinese Journal of Chemistry 2012年第3期30卷 733-737页

作者： Ghalem, Wassima Boulcina, Raouf Debache, abdelmadjid Laboratoire de Synthese des Molecules d＇Interet Biologique Departement de ChimieFaculte des Sciences Exactes Universite Mentouri de Constantine 25000 Constantine Algerie

A facile and efficient synthesis of new 1,4-dihydropyridine derivatives was reported via Hantzsch three-com- ponent condensation reaction of aldehydes or formylphenylboronic acids, ethyl acetoacetate, and ammonium acetate in the presence of a catalytic amount of triethylamine under solvent-free conditions. The method described here of- fers several advantages including high yields, short reaction times, and simple work-up procedure.

关键词： 1,4-dihydropyridine triethylamine formylphenylboronic acid Hantzsch reaction solvent-flee condi-tion

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Contribution of Hydrogeochemical and Isotopic Tools to the Management of Upper and Middle Cheliff Aquifers

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Journal of Earth Science 2020年第5期31卷 993-1006页

作者： Madene Elaid Meddi Hind Boufekane abdelmadjid Meddi Mohamed National Higher School for Hydraulics LGEE-ENSH BlidaAlgeria

In the alluvial aquifers of Upper and Middle Cheliff(North-West Algeria), the groundwater quality is deteriorating. The objective of this study was to characterize the physical and chemical properties of these aquifers;and to evaluate the groundwater quality and its appropriateness for drinking and agricultural use. An investigation was carried out by estimating of the physiochemical parameters(Ca^2+, Mg^2+, Na^+, K^+, Cl^-, SO4^2-, HCO3^-, NO3^-, Br^- and TDS) to identify the chemical characteristics of groundwater. Morever, the isotopic composition was examined to identify the sources of recharge of these aquifers. The groundwater geochemistry for the high water level(May, 2012 and June, 2017) and low water level(November, 2012 and October, 2017) was studied. Accordingly, water samples from 39 water sampling points were collected(October, 2017 and June, 2018), for the purpose of analyzing stable isotopes(18O, 2H). The results show that the groundwater is mainly characterized by Ca-Cl and Na-Cl type. The chemical quality of the water is from fair to poor with the presence of nitrates used in agricultural and urban discharge. Also, the Br/Cl ratio gives indications on the origin of the salinity. This salinity is due to the leaching of chlorinated fertilizers, the dissolution of evaporite deposits and the rise of deep salty water by the fault of Chellif. While, the diagram of δ2H=f(δ18O) indicates that the origin of the recharge of these aquifers is the Atlantic and Mediterranean oceanic meteoric rainwater.

关键词： hydro-chemistry management isotopic analysis groundwater Upper and Middle Cheliff Algeria

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Numerical and experimental comparison of the vaned diffuser interaction inside the impeller velocity field of a centrifugal pump

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Science China(Technological Sciences) 2011年第2期54卷 286-294页

作者： ATIF abdelmadjid BENMANSOUR Saad BOIS Gerard DUPONT Patrick Laboratory of Advanced Mechanics FGMGP/USTHBBP32 El Alia16111AlgerAlgeria Laboratory of Mechanics of Lille ENSAM-Lille8 Bd Louis XIV59046LilleFrance Laboratory of Mechanics of Lille EC-LilleBP48 Villeneuve d’Ascq59651LilleFrance

The paper refers to the analysis of interactions between the impeller and the vaned diffuser based on the air model of a radial flow *** study deals with a numerical simulation of the flow for a full 360°entire impeller and *** task is carried out closely under the design operating conditions and for one particular position of the impeller blade with respect to the diffuser *** all the results,the focus is mainly on the flow pattern at the exit part inside the impeller facing the diffuser *** results are compared to the available PIV measurements.

关键词： centrifugal pump impeller vaned diffuser rotor-stator interaction

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Experimental and statistical investigation of a new concrete-composite beam with encased polymer tube wrapped by FRP

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Frontiers of Structural and Civil Engineering 2015年第2期9卷 154-162页

作者： abdelmadjid SI SALEM Souad AIT TALEB Kamal AIT TAHAR Laboratory LaMoMS the University Mouloud Mammeri of Tizi Ouzou Tizi Ouzou 15000 Algeria

A new concrete-composite beam with high mechanical performances to weight ratio is developed in this study. The proposed design technique consists to embed a cylindrical polymer tube wrapped by a GFRP Jacket in the mechanically ineffective concrete tensile zone. An experimental investigation is carried out on composite beams under bending loads until failure to evaluate the flexural capacity and the corresponding failure mechanisms. Based on the experimental results, statistical and preliminary reliability analyses using the FORM method are performed to assess the safety margin of the new beam. The confrontation between test and simulation results shows a satisfactory agreement, and represents a promising revelation regarding the improvement in terms of strength and ductility of such design compared to conventional reinforced concrete beams with traditional one.

关键词： design GFRP-Jacket polymer tube test reliability analysis

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Tunability of Photonic Band Gaps in One- and Two-dimensional Photonic Crystals Based on ZnS Particles Embedded in TiO2 Matrix

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Photonic Sensors 2012年第2期2卷 180-186页

作者： Amel LABBANI abdelmadjid BENGHALIA Microwave and Semiconductors Laboratory Faculty of Engineering Sciences MENTOURI University ConstantineAin El Bey Road 25000 Constantine Algeria

Using the Maxwell-GarneR theory, the evolution of the refractive index of titanium dioxide （TiO2） doped with zinc sulfide （ZnS） particles is presented. The presence of the nano-objects in the host matrix allows us to obtain a new composite material with tunable optical properties. We find that the filling factor of ZnS nanoparticles greatly alters photonic band gaps （PBGs）. We have calculated also the photonic band structure for electromagnetic waves propagating in a structure consisting of ZnS rods covered with the air shell layer in 2D hexagonal and square lattices by the finite difference time domain （FDTD） method. The rods are embedded in the TiO2 background medium with a high dielectric constant. Such photonic lattices present complete photonic band gaps （CPBGs）. Our results show that the existence of the air shell layer leads to larger complete photonic gaps. We believe that the present results are significant to increase the possibilities for experimentalists to realize a sizeable and larger CPBG.

关键词： Photonic crystals photonic band gap nanoparticles ZnS TiO2

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Physical Properties of the Cathode Materials in Fuel Cells

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Journal of Environmental Science and Engineering(B) 2012年第2期1卷 187-193页

作者： abdelmadjid Temagoult Kafia Oulmi Laboratory of lndustrial Energy Systems （LESEI） Mechanical Department Faculty of Engineering Sciences University of BatnaBatna 05000 Algeria Laboratory of Chem＆try and Environmental Chemistry （LCCE） Faculty of Science University of Batna Batna 05000 Algeria.

The materials used in fuel cells are currently the subject of much research, particularly those of the cathode which is a key element for the different functions that it provides. In our work the authors became interested in the different materials used for the cathode, which are usually ceramic, and some of their physical properties between different electrical conductivity （electronic, ionic）, the coefficient of thermal expansion and chemical compatibility between different materials used in the stack. Not to mention, however, the various parameters that influence these properties, such as structure, the sintering temperature, dope, and the operating temperature of the battery. The main objective of research in this area is to improve battery performance by researching new materials and new manufacturing technologies that will increase the electrical conductivity while trying to lower the temperature operating the latter as much as possible while keeping it above 650℃, In doing so, the longevity of the battery will be increased which will have a direct impact on manufacturing costs of the battery, and thus greater use thereof.

关键词： Ceramic fuel cell cathode electrical conductivity thermal expansion.

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