130 research outputs found

    Anisotropy of the gap energy in high Tc Copper Oxides

    Get PDF
    Within the frame work of BCS phonon-mediated pairing with a logarithmic (2D) Van Hove Singularity in the density of states, we study the anisotropy of superconductors gap taking into account the anisotropy of attractive coupling and the coulomb repulsion .The results show that gap is more disperse and can explain some observed experimental data.Within the frame work of BCS phonon-mediated pairing with a logarithmic (2D) Van Hove Singularity in the density of states, we study the anisotropy of superconductors gap taking into account the anisotropy of attractive coupling and the coulomb repulsion .The results show that gap is more disperse and can explain some observed experimental data

    Risk assessment of mercury and methyl mercury intake via sardine and swordfish consumption in Algeria

    Get PDF
    NO ABSTRACT AVAILABLETotal mercury (Hg) and methylmercury (MeHg) concentrations in the flesh of sardine (Sardina pilchardus) and swordfish (Xiphias gladius) fished in three Algerian coasts were determined by a direct mercury analyzer (DMA). We also assessed the risk to which the consumer was exposed to by calculating the estimated daily intakes (EDIs), target hazard quotient (THQ) and hazard index (HI). The average concentrations of Hg and MeHg in the flesh of sardine were similar (0.04 mg/kg wet weight) and in swordfish were 0.61 mg/kg wet weight; 0.57 mg/kg wet weight, respectively. These concentrations have not surpassed the thresholds set by the Algerian and European regulations. The estimated daily intakes for Hg and MeHg were similar in sardine (0.0064 ÎŒg/kg/day) and were 0.098 ÎŒg/kg/day and 0.092 ÎŒg/kg/day for Hg and MeHg, respectively, in swordfish. These values did not exceed the provisional tolerable weekly intake (PTWI) established by the European Food Safety Authority (EFSA) and by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The target hazard quotient (THQ) and the hazard index (HI) calculated were < 1. Consequently, consumption of these fishes does not pose any risk for the adult groups of the Algerian population regarding mercury, and methylmercury studied

    Removal of methylene blue with a highly effective hydroxyapatite-silica nanocomposite

    Get PDF
    Two Hydroxyapatite-silica nanocomposite adsorbent (HApS220 and HApS230) were successfully synthesized using sol-gel technique. The samples were characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), which confirmed the formation of a Hydroxyapatite-silica nanocomposite. The synthesized powders were then used for adsorption of methylene blue (MB). Both compounds possessed high absorption capacities, the adsorption equilibrium time is around 10 min. HApS230 sample shows higher adsorption capacity compared to HApS220. Furthermore, isotherm studies show that the adsorption used is an ion exchange process and that Temkin isotherm describes the adsorption better compared to the Langmuir and Freundlich and Dubinin-Radushkevich isotherms. Kinetics studies confirm that the adsorption follow the pseudo-second order model and chemisorption mechanism. Thermodynamics’ studies confirm that the adsorption of MB on HApS samples is a spontaneous endothermic process. The average removal effectiveness of MB reached about 89.02% (6.389 mg/g adsorption capacity) and 91.36% (6.55 mg/g adsorption capacity) for HApS220 and HApS230 respectivel

    Monoclinic polymorph of poly[[di-Ό-aqua-triaquadi-Ό-oxalato-barium(II)­copper(II)] monohydrate]

    Get PDF
    A monoclinic polymorph of the title compound, {[BaCu(C2O4)2(H2O)5]·H2O}n, is reported. The structure is best described as a coordination polymer where the CuII and BaII centers are coordinated by five and nine O atoms, respectively, in capped quadratic antiprismatic and tetragonal pyramidal geometries. The polymerization arises due to the presence of bridging mono- and bidentate oxalate ligands as well as bridging water mol­ecules. The crystal structure is consolidated by a three-dimensional network of hydrogen bonding

    Traitement peu invasif d’une breche osteo meningee associee a une hypertension intracranienne benigne

    Get PDF
    Description L’hypertension intracrĂąnienne bĂ©nigne (HTICB) est une augmentation anormale de la pression intracrĂąnienne non associĂ©e Ă  un processus occupant de l’espace intracrĂąnien, une thrombose des veinescĂ©rĂ©brales ou une hydrocĂ©phalie. CaractĂ©risĂ©e par des cĂ©phalĂ©es invalidantes, des acouphĂšnes pulsatiles, elle peut avoir une Ă©volution pĂ©jorative et irrĂ©versible entraĂźnant une cĂ©citĂ©. La survenue d’une rhinorrhĂ©e spontanĂ©e dans un contexte d’HTICB a Ă©tĂ© dĂ©crite dans la littĂ©rature mais demeure peu frĂ©quente. Objectif et cas cliniqueNous rapportons le cas d’une femme obĂšse ĂągĂ©e de 40 ans, qui a Ă©tĂ© admise pour rhinorrhĂ©e droite spontanĂ©e. Les explorations neuroradiologiques ont permis d’évoquer une hypertension intracrĂąnienne bĂ©nigne sur une brĂšche ethmoĂŻdale antĂ©rieure. Le monitoring de la pression a confirmĂ© le diagnostic. Elle abĂ©nĂ©ficiĂ© d’une dĂ©rivation ventriculo pĂ©ritonĂ©ale. L’évolution est favorable (disparition des symptĂŽmes) avec un delai de recul de 16 mois . Conclusion L’HTICB est une pathologie avec des consĂ©quences irrĂ©versibles si le traitement n’est pas adĂ©quat et rapide. En cas de rhinorrhĂ©e isolĂ©e dans le cadre de l’hypertension intracrĂąnienne bĂ©nigne la dĂ©rivation ventriculo pĂ©ritonĂ©ale est une attitude thĂ©rapeutique simple mais efficace

    Ba(H2PO3)2.0.5H2O: Synthesis, crystal structure optimization, vibrational study, DFT computation and application as a corrosion inhibitor

    Get PDF
    This investigation involved the synthesis of barium phosphite Ba(H2PO3)2.0.5H2O by reacting barium chloride with phosphorous acid. The physical characteristics, FT-IR spectra, and X-ray diffraction were employed to validate the composition of the synthesized substance, and powder X-ray diffraction (PXRD) was used to determine the phase purity. The optimal molecular geometry, infrared intensities were calculated using density functional theory (DFT/B3LYP) methods with the LanL2DZ basis set. The HOMO-LUMO properties and geometries of this compound have been determined and discussed. The computational structural parameters are generally in agreement with the experimental investigations. The theoretical infrared for the title compound has been constructed. Additionally, the anti-corrosion properties of this compound were investigated in an acidic solution using weight loss and electrochemical techniques. The results showed good effectiveness, indicating the formation of a protective film on the C38 surface

    Investigation of Rheological and Geometric Properties Effect on Nonlinear Behaviour of Fluid Viscous Dampers

    Get PDF
    Global approval of the use of fluid viscous dampers to control the buildings response against dynamic loadings is growing. The idea behind incorporating additional dampers is that they will reduce most of the energy that is transmitted to the building during shaking event. The objective of this work is to identify and enhance the design parameters that control the nonlinear behaviour of fluid viscous damper subjected to sinusoidal excitation. For this, a numerical model of the flow inside the dissipater has been carried out based on finite volume method. A novel approach has been adopted to simulate elastic behaviour of the fluid, taking into account its compressibility by using the Murnaghan equation of state. A comparison between the calculations of the proposed model and the experimental tests was carried out. The model proved to be sufficiently accurate. A fluid flow analysis was then conducted to fully understand the internal mechanism of the damper. A parametric study was then performed by varying aspects such as dimensions, geometric relationships between components and fluid properties in order to better understand their effect on the non-linear behaviour of the device.  The results highlight the relationship between the parameters governing the shear thinning behaviour of the fluid and the non-linearity exponent of the damper. This makes it possible to better control the non-linear behaviour of the device by selecting the appropriate silicone oil and the appropriate geometric dimensions of its components
    • 

    corecore