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Volume 01 (2017) : Full Volume PDF
1- Excitation cross section of hydrogen atom by proton impact within Schwinger variational principle and pseudo state method.
Adnane BOUSERHANE, Nour El Houda BENMANSOUR and Mammar BOUAMOUD
Abstract – We use Schwinger variational principle to evaluate excitation cross section of atomic hydrogen by proton impact at energy range between 2keV and 200keV. Contribution of the continuum near ionization threshold was introduced in a model using L2 method developed in a pseudo-space spanned by a set of Slater type functions. Our results were compared with those of Bouamoud  using 1s, 2s and 2p state of hydrogen atom.
2- Al molar fraction effect of an AlxGa1-xAs window on the GaAs solar cell.
Leila AYAT, Abderrahmane BELGHACHI and Afek MEFTAH
Abstract – Among compound semiconductor materials, GaAs is commonly preferred for space applications because of its more advanced and cheaper technology, conversion efficiency and radiation resistance. Unfortunately an all-GaAs solar cell suffers from carrier loss due to a high surface recombination velocity, and in order to reduce such loss a wide band gap surface layer of Alx Ga1-xAs is placed on the top of a GaAs emitter to create a heterojunction solar cell. In this paper, the performances of AlxGa1-xAs solar cells, such as short circuit current density, open-circuit voltage, fill factor and efficiency are compared and investigated with different fraction molar of Al using newly SCAPS developed software.
3-Moment quadrupolaire de quelques noyaux pair-pairs de la région 90 < A <120.
Abstract – Electric quadrupole moments of some even-even nuclei of the 90<A<120 region are investigated by means of the macroscopic-microscopic method. We use a realistic equation with Strutinsky shell and BCS pairing corrections. The theoretical values are found quite close to the experimental ones.
4- A Thermal Conduction Comparative Study Between the FDM and SPH Methods.
Mohammed BENSAFI, Noureddine KAID and Abdeldjabar MOUSSAOUI
Abstract – In this work we have studied the propagation of heat with the FDM method and the SPH method, this last is fully embodied in the tree terms of Smoothed Particle Hydrodynamics, could be used for solving complex and an expected problem of applied mechanics. We have FEM for Lagrangian description and FDM for Eulerian description but in many aspects, we can use the SPH method, which is better than other methods to solve some problems. In addition, we discussed numerical details with a focus on numerical implementation, interpretation of the heat equation. The newly constructed quartic smoothing function and the SPH approximation procedure are applied to simulate a simple two-dimensional heat conduction problem. Then we have also compared them and finally we proposed a C++ code for SPH and FDM methods.
5- The influence of horizontal vibratory excitation on the behavior of a nanofluid in natural convection.
Syham KADRI, Razli MAHDAOUI, Mohammed ELMIR
Abstract – The objective of the present work is to study the effect of horizontal vibratory excitation on the behavior of a water-Al2O3 nanofluid in natural convection in a cavity. The nanofluid used is composed of aluminum oxide nanoparticles in suspension of water, is provided at various volume fractions. The two horizontal walls are isothermal, maintained at cold temperature Tc and heat temperature Th. The two vertical walls are adiabatic. The basic equations describing the flow driven by natural convection consist of mass conservation, momentum and energy. For the physical parameters of Al2O3+water nanofluid, we use the Brinkman and Wasp model. Transport equations are solved numerically by finite element method. Results are presented in the form of streamlines, isotherms and the flux ratio.
6- The dynamic behavior of the valves refrigerating compressors system of the solar application.
Rachid KHELFAOUI, Maiouf BELHAMEL and Boumediene BENYOUCEF
Abstract – In this work, we will present a calculation method of the instantaneous values of some variables necessary for the dynamic description of the bending valves of the hermetic compressors of refrigeration uses for the solar application. Among the existing methods in the literature, we chose the WAMSBSGANSS AND COHEN method . Our interest is related to the dynamic aspect of the bending valves.
7- Charge Transport in Fullerene (C60) Schottky Diode.
Mebarka DAOUDI, Nesrine MENDIL, Zakarya BERAKAI and Abderrahmane BELGHACHI
Abstract – In order to optimize the device performance, it is very important to have knowledge about intrinsic properties, particularly the charge transport and charge injection properties. One of the basic methods to investigate the charge transport in interface metal/organic semiconductor is to determine the dark current density-voltage characteristics. Space charge, trapping and Schottky barrier height effects are the important effects, which describe that transport mechanism. These are obtained from the dependence on the temperature, electric field and trap density. In this work, we studied the electronic transport in Fullerene organic Schottky diode which is strongly affected by interface phenomena.
8- Experimental study and modeling of moisture sorption isotherms of leaves (Waronia saharae).
Said BENNACEUR, Belkacem DRAOUI, Lyes BENNAMOUN and Boumedienne TOUATI
Abstract – The equilibrium moisture contents were determined for Waronia saharae leaves using the gravimetric static method at T = 30, 40 and 50 °C over a range of relative humidities from 0.05 to 0.9.The sorption curves of Waronia saharae decreased with increase in temperature at constant relative humidity. The hysteresis effect was observed. The Peleg , GAB, modified Halsey, modified Oswin Modified BET, and modified Henderson models tested to fit the experimental data. from The Peleg model was found to be the most suitable for describing the desorption curves and GAB For adsorption.
Volume 02 (2018) : Full Volume
1- Contrôle actif de l’instabilité hydrodynamique d’un écoulement externe sur une paroi perméable
Abdelghani LAOUER, Mounir BOUTELDJA, Elhacene MEZAACHE
Résumé – Ce travail est consacré à l’analyse de la stabilité temporelle linéaire d’un écoulement externe laminaire sur une paroi soumise à un transfert pariétal de masse par injection ou aspiration. L’écoulement de base est supposé laminaire et bidimensionnel. Les profils de vitesse de l’écoulement de base sont obtenus numériquement par la méthode de Runge-Kutta. Les perturbations de ces solutions de base sont exprimées sous forme d’ondes bidimensionnelles de Tollmien-Schlichting. La formulation du problème de stabilité conduit à l’équation d’Orr-Sommerfeld. Cette équation est résolue numériquement en utilisant la méthode de collocation spectrale de Chebyshev. Cette méthode nous a permis d’obtenir les diagrammes de stabilité marginale, les nombres de Reynolds critiques et les spectres des fonctions propres pour différentes valeurs de la fonction de courant imposée. Les solutions numériques indiquent l’importance de l’effet d’injection et d’aspiration sur les caractéristiques de stabilité de l’écoulement.
2- Investigation of thickness effect on the charge carrier mobilities of C60 and SubPc Schottky diodes
Nesrine MENDIL, Mebarka DAOUDI, Zakarya BERKAI, Abderrahmane BELGHACHI
Abstract – Our study is focused on the active layer thickness effect on the mobility for electron in fullerene (C60) and hole in Boron Subphthalocyanine Chloride (SubPc) organic Schottky diode structures, in order to obtain the optimal thickness for the best efficiency. It is found that, the optimum value of active layer thickness is d=200nm (C60) and d=50nm (SubPc) for both low applied voltage (~0V) and temperature (<295K) where the Gaussian disorder energy is 0.03eV. In these conditions, the charge carrier mobility is reached 1.818×10-1 cm2/V.s and 9.1×10-8 cm2/V.s for electron and hole, respectively. Against, when the temperature is increased above 295K where the Gaussian disorder energy is 0.06eV the optimum thickness value is around d~40nm and d~5nm for electron and hole, respectively. In this case the Gaussian disorder energy and applied voltage affect the carrier’s mobility dramatically. Our results are in good agreement with those extract from J.Holmes et al (Adv Funct Mater 22:617–624, 2012).
3- One-dimensional analytical solution of the Schrodinger equation using the periodic delta potential
Bouziane AZEDDINE, Mebarka DAOUDI
Abstract – The most basic problem in quantum mechanics is to solve the stationary Schrodinger equation. There are a number of important cases for which the stationary Schrodinger equation can be solved analytically. In the present paper, this equation is analytically solved using the approach of single electron moving in a periodic delta potential. We can obtain from this approach that without mentioning at the beginning the solution is a plane wave, the final result is it, and the periodicity of the lattice is provided by term associated with the Heaviside function.
4-Numerical Study of Natural Convection Heat Transfer in Rectangular Enclosures
Rida ZARRIT, Mohamed TEGGAR and Sofiane KHERROUR
Abstract – The objective of this numerical investigation is to study natural heat convection in a rectangular cavity filled with air. The enclosure is differentially heated. The mass, momentum and energy equations, adopting the Boussinesq approximation, are numerically solved using the finite-volume method and the SIMPLEC algorithm. The effect of the aspect ratio, angle of inclination of the enclosure for Rayleigh number ranging from Ra=103 to Ra=106. Results showed that the enclosure orientation, the aspect ratio and Rayleigh number have strong effect on the flow structure and heat transfer in the cavity. Besides, correlations for average Nusselt-Rayleigh are then proposed.
5-Improvement of Optoelectronic Properties of Ferroelectric Lithium Niobate
Souheyla MAMOUN, Abdelkrim Elhasnaïne MERAD and Laurent GUILBERT
Abstract– We present in this work a detailed analysis of the electronic and optical properties of ferroelectric lithium niobate using ab initio FP-LAPW method. The electronic band structure is detailed by analysing the total and partial densities of states. In order to overcome the inherent inaccuracy of DFT calculations based on the single particle approach, corrected dispersions of the dielectric function, the refractive index, the absorption coefficient and the electron energy loss function are calculated using the scissors operator. A good agreement is obtained between theoretical and experimental data.
6- Effects of substitutional site in mechanical behavior of highly reactive nanostructured iron phosphides alloys
Wassila TEBIB, Ismahane CHENOUGA
Abstract– Nanocrystalline Fe-xP (x = 10, 15, 20 wt. %) powders ground for 24 hours in a Fritsch P7 were found to predominate the substitution sites. The formation of substitution solid solutions was detected using the Rietvelt method by the shift of the Bragg peaks of the host matrix. The small difference in size between the Fe (r = 0.125 nm) and P (r = 0.128 nm) atom allows the phosphorus atoms to replace some iron atoms to form a substitution solid solution with two structures, a -Fe (P), and little distortion of the crystal lattice. The new formed phases, FeP2, Fe2P and Fe3P, emerge on the X-ray diffractograms as a new diffraction peaks. They result from two mechanisms of interaction of the interstices with the atom P: the displacement of the P atom from a substitutional Fe site to combine with an interstitial and / or attraction of the interstitial site of Fe to the substitution atom P caused by the stresses present in the vicinity of P which plays the role of an attraction center for Fe interstitials and stabilizes them by forming phosphorus nano-clusters.
1-Effect of Gallium and Aluminum on the electronic and optical properties of Zn1-x-yGaxAlyO up to (x,y)=(25,12.5)%
Hiba Imene BERREZOUG, Abdelkrim El Hasnaïne MERAD and Zakaria SARI HASSOUN
Abstract– We present, in this paper a comparative study of structural, electronic and optical properties of pure ZnO and ZnO co-doped with gallium and aluminum at different concentration Zn1-x-yGaxAlyO up to (x, y)=(25,12.5) %. The calculated structural parameters were obtained using the Generalized Gradient Approximation (GGA-PBE). The electronic structure, the imaginary part of the dielectric function, the absorption coefficient, and the reflectivity were determined using the modified Becke-Johnson potential (mBJ). We have found that these elements present a good optical conductivity with a significant improvement for the ZnO co-doped (Al, Ga) at different concentrations compared to the pure ZnO. The results for pure and co-doped ZnO are in a good agreement with experimental results and other theoretical studies and confirm their usability in photovoltaic devices.