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Role of the injection water microorganisms on corrosion of fiberglass in TFT Algerian oil fields
No full textNumerical simulation of the direct contact condensation phenomena for PTS-related in single and combined-effect thermal hydraulic test facilities using TransAT CMFD code
No full textHydrogen sensing properties of the ZnO (0 0 0 1 ¯) surface enhanced by Be doping : a first principles study
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Effect of stress-strain conditions on physical precursors and failure stages development in rock samples
No full textPrecursory stages of failure development in large rock samples were studied and simultaneous observations of the space-time variation of several physical fields were carried out under different stress-strain states. The failure process was studied in detail. A hierarchical structure of discreet rock medium was obtained after loading. It was found that the moisture reduced the rock strength, increased the microcrack distribution and influenced the shape of the failure physical precursors. The rise in temperature up to 400 °C affected the physical precursors at the intermediate and final stages of the failure. Significant variations were detected in the acoustic and electromagnetic emissions. The coalescence criterion was slightly depending on the rock moisture and temperature effect. The possibility of identifying the precursory stage of failure at different strain conditions by means of a complex parameter derived from the convolution of physical recorded data is shown. The obtained results point out the efficiency of the laboratory modelling of seismic processe
Draft genome sequence of the algerian bee apis mellifera intermissa
Get PDFApis mellifera intermissa is the native honeybee subspecies of Algeria. A. m. intermissa occurs in Tunisia, Algeria and Morocco, between the Atlas and the Mediterranean and Atlantic coasts. This bee is very important due to its high ability to adapt to great variations in climatic conditions and due to its preferable cleaning behavior. Here we report the draft genome sequence of this honey bee, its Whole Genome Shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession JSUV00000000. The 240-Mb genome is being annotated and analyzed. Comparison with the genome of other Apis mellifera sub-species promises to yield insights into the evolution of adaptations to high temperature and resistance to Varroa parasite infestatio
Comparative study of radiative effects on double diffusive convection in nongray Air-CO2 mixtures in cooperating and opposing flow
Get PDFThis study analyses the effects of nongray gas radiation on double diffusive convection, in a square differentially heated cavity filled with air-CO2 mixtures, when the buoyancy forces (thermal and mass) are cooperating or opposing. The radiative source term in the energy equation is evaluated by the discrete ordinate method (solving the radiative transfer equation) and the SLW spectral model (accounting for real radiative properties of absorbing species). Here, gas absorption varies with the local temperature and concentration of pollutant, which induces a strong direct coupling between the concentration and thermal fields that would not exist with gray gas. Simulations are performed at different concentrations of CO2 corresponding to different flow regimes (thermal, transitional, and mass). Results show the following: (i) in cooperating flow, radiation modifies essentially the heat transfer and the characteristics of temperature and concentration fields; (ii) in opposing flow, radiation effects are more important and depend on the nature of the flow regim
Colloidal behavior of aqueous montmorillonite suspensions in the presence of non-ionic polymer
No full textIn this paper we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of polyethylene oxide (PEO), then we were investigated the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non ionic polymer with molecular weight 6×103 g/mol. of varying concentration mass (0.7%, 1%, 2% et 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by X-rays diffraction also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand. The Herschel- Bulkley rheological model is used for the correlation of our experimental result