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Bechar, Algeria

The Université de Béchar is a university located in Béchar, Algeria. It was established in 1986. Wikipedia.

Geochemical data on dissolved major constituents in groundwater samples from Meng Xu area reveal the main processes responsible for their geochemical evolution. Inverse models were developed using PHREEQC to elucidate the chemical reactions controlling water chemistry. The inverse modeling demonstrated that relatively few phases are required to derive water chemistry in the area. In a broad sense, the reactions responsible for the hydro chemical evolution in the area fall into four categories: dissolution of CO 2; calcite dissolution; incongruent dolomite dissolution, dedolomization, ex-solution of CO 2, and ion exchange. Apart from this process, there are others which influence the geochemical zoning of the system. The interaction of the CO 2 with the carbonate matrix of the aquifer produces an increase in the alkalinity of the water. © 2012 Published by Elsevier Ltd. Source

Amrousse R.,Japan Aerospace Exploration Agency | Tsutsumi A.,Japan Aerospace Exploration Agency | Bachar A.,University of Valenciennes and HainautCambresis | Lahcene D.,Bechar University
Applied Catalysis A: General

A novel total decomposition of N2O was performed on the nano-sized particles of substituted CoxFe3-xO4 magnetite (with x = 0-1). The given results showed that the partial incorporation of Fe2+ by Co2+ into Fe3O 4 spinel substrate led to a significant amelioration in the catalytic activity for the N2O catalytic reaction. Furthermore, the catalytic activity of prepared substances depended on the Fe2+ substitution amount by Co2+ cation. The N2O conversion achieved 100% over the nano-sized Co0.6Fe2.4O4 catalyst at 255, 285 and 291 °C for pure N2O, N2O with the presence of oxygen and N2O in the presence of water steam, respectively. A relative increasing of decomposition temperatures was observed after O2 addition. Moreover, the characterization of all samples showed that the catalyst surfaces contain nano-size particles accompanied by well distribution. © 2012 Elsevier B.V. Source

Belhachemi M.,Bechar University | Belhachemi M.,University of Science and Technology Houari Boumediene | Addoun F.,University of Science and Technology Houari Boumediene
Desalination and Water Treatment

To enhance congo red (CR) removal from aqueous solution, activated carbons prepared from date pits and modified by oxidation with nitric acid followed by heat treatment in a nitrogen atmosphere were tested. Kinetic and equilibrium adsorptions data of CR from aqueous solution were carried out, showing that the elimination of oxygen surface groups from activated carbon by heat treatment enhanced the adsorption capacity. The adsorption followed pseudosecond order kinetics. The experimental isotherms were analysed with two and three parameters equations (Freundlich, Langmuir, and Redlich-Peterson) using non-linear regression. The results showed that the Langmuir and Redlich-Peterson isotherms best-fit the equilibrium data, with maximum adsorption capacity of 105 mg/g calculated from Langmuir equation. The mechanism adsorption of this anionic dye on activated carbons involved electrostatic and dispersive interactions. © 2012 Desalination Publications. All rights reserved. Source

Mohammed-Azizi B.,Bechar University
Electronic Journal of Theoretical Physics

The goal of the present work is to revisit the cranking formula of the vibrational parameters, especially its well known drawbacks. The latter can be summarized as spurious resonances or singularities in the behavior of the mass parameters in the limit of unpaired systems. It is found that these problems are simply induced by the presence of two derivatives in the formula. In effect, this formula is based on the hypothesis of contributions of excited states due only to two quasiparticles. But it turns out that this is not the case for the derivatives. We deduce therefore that the derivatives are not well founded in the formula. We propose then simply to suppress these terms from the formula. Although this solution seems to be simplistic, it solves definitively all its inherent problems. © Electronic Journal of Theoretical Physics. Source

Pavement performance and the viscoelastic behaviour of bitumen, transmitted to the asphalt wearing course, depend mainly on the qualities behind the binder and its thermal history on the site. The current climate changes generate exceptional variations in temperature. Changes in the climatic environment, such as sudden changes in temperature, the surface layers exhibit a severe cyclical freeze/thaw in winter or in cold region. During the summer or in hot region the phenomenon of heating/cooling causes hardening of the binder and therefore the pavement. The regional thermal factor and his instability, in the same day, have a significant role in the evolution of viscoelastic properties of the binder on site and remain the main causes of pavement deteriorations. Two types of thermal cycles were simulated in the laboratory on samples of asphalt of the same origin, followed by a creep-recovery characterization using the DSR. An analogue model of three elements has been proposed to simulate the rheological behaviour of binders. We recorded significant differences in rheological response, such as the evolution of viscoelastic properties and deformability, according to the type of thermal cycle and the applied number. These differences are found between the original sample and all samples that have undergone thermal cycling on the one hand, and between the two types of heat treatment of the other. The behaviour of the asphalt binder, after certain number of thermal cycle (operating period) depends on the nature and characteristics of climate in the region and the exposure time of the binder to thermal cycles. The geo-climatic factor and its changes have become essential parameters in the prediction of pavement behaviour on site and estimation of their life. © 2012 Published by Elsevier Ltd. Source

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