Journal Articles

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Open Access
CuO nanocrystals embedded in KBr single crystal: Elaboration and Characterization
(Université de M'sila, 2017) Bouhdjer, Lazhar
More recently, there are important number of papers which have been stimulated by the optical characteristics of crystalline matrixes doped with quantum dots (QDs), nanoparticles (NPs) or nanocrystals (NCs) of semiconductors. In this context, we suggest this investigation, which highlights the doping effects of CuO (NCs) on structural and optical properties of KBr single crystal. In this approach, we expose a simple and realizable technique for embedding CuO NCs as three dimensions (3D) defects in a KBr crystalline matrix. The Czochralski method was used to obtain a KBr:CuO single crystal starting from inhomogeneous phase melt-NCs in the crystallization melting-pot. However, the nano-regime of guest material creates a difficult challenge, because there is a possibility of fusing of the CuO NCs during the crystal growth process. Nevertheless, the whole structural results prove that the NCs inside KBr:CuO single crystal have monoclinic phase with nano-regime size. In addition, these results appear that the CuO NCs have two orientations preferred inside KBr host and demonstrate that the chemical bond Cu-O of CuO monoclinic phase steel exists. Relative to the optical properties, the UV–Visible absorption spectroscopy exhibits that the NCs inside KBr:CuO sample have a nano-regime size, where the band gap shifts toward the higher energies. Furthermore, photoluminescence (PL) of KBr:CuO single crystal appears an important intensity in the visible range, this property makes this sample as a good candidate to integrate them in the optical devices which are working in the visible range.
Open Access
The effect of Al and In concentrations on the properties of electrodeposited Cu(In,Al)Se2 using two electrode system without the addition of complexing agents
(Université de M'sila, 2017) Meglalia, Omar
Chalcopyrite Cu(In,Al)Se2 thin films were deposited by electrodeposition process onto ITO coated glass substrates from de-ionized water solution consisting of CuCl2, InCl3, AlCl3 and SeO2 precursors. The effect of Al and In concentrations in precursor solutions on the properties of Cu(In,Al)Se2 films were investigated by varing x ratio (x = [Al]/[In + Al]) from 0 to 0.75. The structural, optical and electrical properties of films were studied, respectively, using X-ray diffraction, Raman spectroscopy, UV-visible spectrophotometer, Hall-effect and four-point probe method. The X-ray diffraction analysis proved that the film deposited at x = 0.75 present Cu(In,Al)Se2 single phase in its chalcopyrite structure and with preferred orientation along [112] direction, however the others films show the main Cu(In,Al)Se2 chalcopyrite with the formation of In2Se3 as a secondary phase. The band gap energy of the films was controlled from 1.17 to 1.65 eV by adjusting the Al and In concentrations in the precursor solutions. The Raman analysis revealed that all the films mainly consist of a chalcopyrite structure and the film deposited at x = 0.25 contain the ternary compounds CuAlSe2 as secondary phase. This last film showed n-type conduction while the rest of the films showed p-type conduction. The electrical resistivity is in the range of 0.06–1.9 cm.
Open Access
CuInTe2 thin films synthesis using one-step electrodeposition process: structural, optical, and electrical characterization
(Université de M'sila, 2018) Meglali, Omar
Polycrystalline CuInTe2 (CIT) films were grown onto ITO substrate by one-step electrodeposition technique using acidic aqueous solutions. In this study, the influence of the deposition time on CIT films properties was examined using six techniques, the X-ray diffraction, the scanning electron microscopy, the energy dispersive X-ray analysis, the optical transmittance, the Raman spectroscopy and the electrical properties measurements. The thickness of CuInTe2 films increases as the deposition time increases. The X-ray diffraction investigation of the films deposited during 5 and 10 min shows up only a tetragonal CuInTe2 chalcopyrite structure, with a preferred orientation along [112] direction. However, the films deposited during 15 and 20 min exhibits the CuInTe2 chalcopyrite structure as a main phase with In4Te3 as additional secondary phase. We have noticed a change in the preferred orientation axis of the prepared films as function of deposition time. The films show the direct allowed band gap and their energy band gap decreased from 1.06 to 0.99 eV as the deposition time increased from 5 to 20 min. Hall effect measurements show that the deposition time changes the conductivity type and films carrier concentration. The electrical conductivity is affected by the variation in the carrier mobility rather than by their concentration. The observed Raman modes in the films match well with those reported for single crystal CuInTe2 in the literature. All Raman spectra show the A1 mode at 127 cm−1 confirming the chalcopyrite crystalline quality of these films.
Open Access
Exact analytical results for density profile in Fourier space and elastic scattering function of a rotating harmonically confined ultra-cold Fermi gas
(Université de M'sila, 2018) S.Medjedel; K.Bencheikh
In this paper, the system dealt with consisting of an ultra-cold neutral spin-polarized Fermi gas undergoing rotation (or in the so-called synthetic magnetic field) trapped by an anisotropic harmonic potential in a two and three-dimensional space at zero temperature. Using the so-called Bloch propagator as a tool, we derive exact closed-form expressions for particle density in Fourier space which are valid for an arbitrary particle number confined by a two and three-dimensional rotating anisotropic harmonic trap. Numerical illustrations and discussions are presented. The results can be easily generalized at finite temperatures. The crossover from two-dimensional to the one-dimensional regime is shown to be reflected in the shape of the density distribution in Fourier space at very fast rotating velocity (or at strong synthetic magnetic field). In addition, an exact analytical expression of the elastic scattering factor is found, a quantity of interest used to probe the spatial distribution of the quantum gases
Open Access
Heat treatment and kinetics of precipitation of β-Mg17Al12 phase in AZ91 alloy
(Université de M'sila, 2018) M. Fatmi; A. Djemli; A. Ouali; T. Chihi; M.A. Ghebouli; H. Belhouchet
This study investigated the effect of aging on the precipitation and kinetics of second phase Mg17Al12 in AZ91 magnesium alloy (Mg-9 wt% Al-1 wt% Zn), using X-ray diffraction, microhardness measurements and differential scanning calorimetric analysis (DSC). With the last instrument, the all samples were heated from room temperature to 400 °C, at heating rates of 10–30 °C/min. The results were supplemented by measuring the average of activation energies, using isothermal treatments by Johnson–Mehl–Avrami (JMA) methods and by non-isothermal treatments using Ozawa, Boswell, Kissinger, Mahadevan, Augis and Bennett methods, were around 67.18 and 62.02 kJ/mol. The frequency factor k0 calculated by the isothermal treatment is equal to 1.24 109 s−1. In non-isothermal treatment, the numerical factor m and the Avrami parameter n is estimated to be approximately equal to 3 and 2.79 respectively. This value corresponding that the bulk nucleation with a constant number of nuclei was dominant in three-dimensional (polyhedron) controlled by interface reaction.
Open Access
Journal of Advanced Research in Fluid Mechanics and Thermal Sciences
(Université de M'sila, 2018) Benderradji, Razik
In this work, we present a numerical study of mixed convection heat exchange in a cubic cavity of a laminar three-dimensional (3D) incompressible flow. This study predicted the behavior of the flow structure between Multi clear structure dominated by natural convection when the Reynolds number is small, and a Multi clear structure dominated by forced convection when the Reynolds number is high. First, we fix the Grashof number for the variable Reynolds number. Second, we vary the number of Grashof for which the Reynolds number is kept fixed. The results obtained give a clear comparison with those found in the literature it examines and explains the thermal and dynamic characteristics of the flow.
Open Access
Effect of hot rolling on the corrosion behavior of AZ31 magnesium alloy
(Université de M'sila, 2018) Abdelkader Hanna; Achour Dakhouche; Kamel Tirsatine; Ali Sari; Yazid Khereddine; Djamel Bradai; Hiba Azzeddine
The aim of the present study is to investigate the effect of deformation conditions on the corrosion behavior of AZ31 (Mg-3Al-1Zn,%wt.) in 0.9% NaCl (wt.%) solution. The AZ31 alloy was hot rolled at 360 °C to 20 and 50% of thickness reduction. Electrochemical measurements were used to study the corrosion behavior of AZ31 alloy. Analysis of corrosion products after immersion test was performed using optical microscopy, X-ray diffraction and Raman spectroscopy. The mechanical properties of corroded samples were investigated using tensile test at room temperature. Results indicated that the corrosion rate was strongly affected by the hot rolling level. A lower corrosion potential and reduced polarization resistance was observed after hot rolling compared to the as received AZ31 alloy. The corrosion product was evidenced mainly as Mg(OH)2 compound exhibiting a filiform-like morphology. Apparently, the corrosion improved the room temperature ductility of AZ31 alloy.
Open Access
STUDIES ON STRUCTURAL, SURFACE MORPHOLOGICAL, OPTICAL, LUMINESCENCE AND UV PHOTODETECTION PROPERTIES OF SOL–GEL Mg-DOPED ZnO THIN FILMS
(Université de M'sila, 2018-03) MAHROUG, Abdelhafid
Undoped and magnesium-doped zinc oxide thin ¯lms were prepared by the sol–gel method. Results from X-ray di®raction indicated that the ¯lms exhibited a hexagonal wurtzite structure and were highly oriented along the c-axis. The intensity of the (002) di®raction peak increased with increasing the Mg doping concentration. Also, Mg doping inhibited the growth of crystallite size which decreased from 46nm to 38nm with doping concentration. Morphological studies by atomic force microscopy (AFM) indicated the uniform thin ¯lm growth and the decreasing of grain size and surface roughness with Mg doping. Optical analysis showed that the average transmittance of all ¯lms was above 90% in the visible range and Mg doping has signi¯cantly enhanced the bandgap energy of ZnO. Two Raman modes assigned to E2L and E2H for the ZnO wurtzite structure were observed for all ¯lms. UV emission peak and three defect emission peaks in the visible region were observed by photoluminescence measurements at room temperature. The intensity ratio of UV emission to the visible emission increased with the Mg concentration. Photocurrent measurements revealed that all ¯lms presented the photoresponses with n-type semiconducting behavior and their
Open Access
Incorporation of CdSe quantum dots (QDs) in KH2PO4 (KDP) crystalline host: Processes of elaboration and characterization
(Université de M'sila, 2018-04) Samyia, Addala
The aim of this work is to survey experimentally the effect of doping CdSe quantum dots (QDs) on structural and optical properties of Di-hydrogen phosphate KH2PO4 (KDP) single crystal, where we expose a simple and reproduced technic to obtain KDP:CdSe single crystal starting from aqueous solution phase. In order to characterize the samples comfortably, the obtained crystals were cleaved into pellets with suitable size each surface being parallel to the faces (100). The XRD results denote that the CdSe QDs inside KDP single crystal have only one preferred direction (110) and the estimated size as derived from Sheere’s formula proved the nano-regime of guest material. On the other side, UV–vis absorption spectrums appear that a pure KDP crystal has transparence property in the visible range with a large window where Eg (KDP) ≈ 7.17 eV. However, KDP:CdSe sample exhibits two bands located at 425 nm and 625 nm attributed to the transition band to band and excitonic, respectively. As an accordance result, photoluminescence (PL) measurements indicate that the band gap of CdSe QDs inside KDP single crystal appears a significant amount of blue-shift ( Eg = 0.284 eV) due to well recognized quantum confinement effect exerted by the CdSe QDs. Published by Elsevier GmbH.
Open Access
Polymorphismes génétiques des donneurs de sang en Algérie à travers les groupes sanguins ABO, RH et Kell
(2018-11) Sabrina, Bounab; Leila, Benazzi; Merzouk, Yahiaoui; Benazi, Nabila
Notre étude a porté sur 2465 donneurs de sang des deux sexes non apparentés, et originaires de Msila(Algérie), au niveau de centre de transfusion sanguine de Msila (CTS), dans un but de réaliser une car-actérisation anthropo-génétique de la population de Msila, en étudiant les trois systèmes polymorphesérythrocytaire ABO, Rhésus et Kell avec leurs fréquences allyliques. Ce qui nous a permis de démontreraprès une analyse comparative multivariées à travers une ACP et une CAH. D’un coté, en comparant lapopulation de Msila aux différentes régions de l’Algérie où on a trouvé une proximité génétique avecle Grand Sud algérien en allant vers le sud-est de l’Algérie. D’un autre coté, l’analyse comparative dela population de Msila avec des populations dans le monde à travers ces trois systèmes sanguins etleurs fréquences allyliques et basés sur le profil historique, géographique et culturel, en construisant unmodèle parental potentiel tri-hybride (Nord Afrique, pourtour méditerranéen et Moyen Orient) ce quinous a permis de déterminer quatre parents potentiels dont l’Egypte et la Lybie (Nord Afrique) et l’Arabiesaoudite et Yémen-sud (Moyen Orient), par contre nous n’avons pas trouvé du lien parental potentiel avec∗
Open Access
First principles study of the structural, elastic and thermodynamic properties of the cubic perovskite-type SrTiO3
(Université de M'sila, 2018-12) Benyettou, Samia
Structural, elastic modulus for the SrTiO3 crystal in the cubic (Pm3m) phase were calculated by the first-principles calculations using the plane wave pseudo potential calculations (PP-PW) im-plemented in the ABINIT package within density functional theory and the generalized gradient approximation based on the Perdew–Burke–Ernzerhof (PBE-GGA) functional. The thermody-namic properties have been investigated by using the GIBBS program, which is based on the qua-si-harmonic model of Debye. The structural parameters (lattice constant, bulk modulus), mechanical (elastic constant, Young’s Modulus, shear modulus and Poisson’s ratio), thermodynamic properties (the variation of the volume, bulk modulus and thermal expansion coefficient, heat capacity at constant volume CV, heat capacity at constant pressure CP and entropy) as function of temperature of the SrTiO3 cubic phase, are studied. The results of our simulations are discussed and compared to experi-mental and theoretical results when available.
Open Access
Natural convective heat transfer from a heated horizontal elliptical cylinder to its coaxial square enclosure
(Université de M'sila, 2018-12) Abdelkarim, Bouras
A numerical study of the natural convection of laminar heat transfer in the stationary state in a horizontal annular space between a heated square inner cylinder and a cold elliptical outer cylinder was investigated. This annular space is traversed by a Newtonian and incompressible fluid. The Prandtl number is set to 0.71 (air case) for different Rayleigh numbers. The governing equations of the problem were solved numerically by the commercial code Fluent, based on the finite volume method and the Boussinesq approximation. The inner and outer surfaces are isothermal. The study was performed for Rayleigh numbers ranging from 1.3 × 103 to 5.5× 105. Particularly, we have studied the effects of different thermal Rayleigh numbers on natural phenomenon convection. The results were presented in the form of isotherms, streamlines, and local and average Nusselt numbers. The purpose of this study is to observe the influence of the thermal Rayleigh number on the structure of the flow and distribution of the temperature.
Open Access
Electro-vibrational Ising-type model for spin crossover in binuclear molecules
(Université de M'sila, 2019) A Metatla; H Latelli
spin crossover in binuclear molecule is investigated using an Ising-type model, including the intramolecular vibrations. The spin transition curve of [Fe(bt)(NCS)2]2bpym complex which presents a two-step transition plateau is well described by the above model. We show that the equilibrium low-spin/high-spin temperature Teq is independent of the vibration frequencies of the intermediate state (HS–LS or LS–HS) xLHS. In addition, a large values of LS–LS state vibration frequencies xLLS lead to an evident two-step transition plateau.
Open Access
Laminar Natural Convection Study in a Horizontal Half- Elliptical Enclosure Using Heater on Horizontal Wall
(Université de M'sila, 2019) Abdelkarim, Bouras
A numerical analysis of laminar natural convection in a horizontal annulus between an internal heated plane and an external cold half-elliptical was investigated using approximation of Boussinesq. Both internal and external walls are maintained at the constant temperature and air is the working fluid. Numerical solutions are obtained using a commercial computational fluid dynamics package, FLUENT, using the finite volume method. Effects of the Rayleigh number, Rat, on the Nusselt number, Nu, as well as velocity and temperature fields are investigated for the range of Rat from 1.0 103 to 5.0 105. The results show that for a small thermal Rayleigh number, the heat transfer within the annulus is essentially controlled by the conduction process. As the thermal Rayleigh number increases (Rat ≥ 104), the role of convection becomes predominant. Also the heat transfer rate increases. The aim of this study is to observe the effects of thermal Rayleigh numberon the structure of the flow and the distribution of the temperature.
Open Access
Electronic and Optical Properties of the Spinel Oxides GeB2O4 (B = Mg, Zn and Cd): An Ab-Initio Study
(Université de M'sila, 2019) Djamel, Allali
We report ab-initio density functional theory calculations of the electronic and optical properties of the spinel oxides GeMg2O4, GeZng2O4 and GeCd2O4 using the full potential linearized augmented plane-wave method. To calculate the electronic properties, the exchange-correlation interaction was treated with various functionals. We find that the newly developed Tran–Blaha modified Becke–Johnson functional significantly improves the band gap value. All considered GeB2O4 compounds are direct band gap materials. The band gap value decreases with increasing atomic size of the B element. The decrease of the fundamental direct band gap ( – ) when one moves from GeMg2O4 to GeZn2O4 to GeCd2O4 can be attributed to the p–d mixing in the upper valence bands of GeZn2O4 and GeCd2O4. The lowest conduction band, which is mainly originated from the s and p states of the Ge and B (B = Mg, Zn, Cd) atoms, is well dispersive, similar to that of transparent conducting oxides such as ZnO. The topmost valence band, which is originated from the O-2p and B-d states, is considerably less dispersive. Optical spectra in a wide energy range from 0 to 30 eV are provided and the origin of the observed peaks and structures are assigned. We find that the zero-frequency limit of the dielectric function (0) increases with decreasing band gap value.
Open Access
Ab initio full-potential study of the fundamental properties of chalcopyrite semiconductors XPN2 (X=H, Cu)
(Université de M'sila, 2019-03) Torkia, Ghellab; Baaziz, H; Zolikha, Charifi; K, Bouferrache; Saeed, M A; Telfah, A
This article reports the electronic, optical and structural properties of XPN2 (X=H, Cu) chalcopyrite semiconductors by implying the density functional theory (DFT) with full potential linearized augmented plane wave plus local orbitals (APW+lo) method. The calculated electronic and structural parameters such as energy band gap, anion displacement, tetragonal ratio and lattice parameters have shown good agreement with the previous experimental and theoretical results. The optical properties are described by calculating the absorption coefficients, dielectric function along with real and imaginary part of the dielectric function. Voigt-Reuss-Hill approximations are used to calculate the set of macroscopic elastic moduli including average elastic wave velocity, Young, shear and bulk moduli, Debye temperature and Poisson’s coefficient for chalcopyrite CuPN2 andHPN2. Finally, the semi-classical Bolzmann theory is applied with BolzTrap code to compute the transport properties such as thermal electrical conductivity, figure of merit and Seebeck coefficient for these materials.
Open Access
Effect of annealing temperature on structural and optical properties of copper oxide thin films deposited by sol-gel spin coating method
(Université de M'sila, 2019-12) TOUKA, Nassim
In this study, CuO thin films synthesized via simple sol-gel method, have been deposited on glass substrates by the spin coating technique and annealed at various temperatures. Samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) and Raman spectroscopy, and UV-visible spectroscopy. The structural characterization by XRD reveals that the as prepared films were tenorite phase and have a high level of purity and crystallinity. The crystallite size of the CuO films was affected by the annealing temperature and was estimated in the range 20-31.5 nm. SEM images show a homogeneous distribution of spherical nanoparticles over the surface of the annealed films at 350 and 450 °C. Vibrational Spectroscopy revealed vibration modes specific to CuO with monolithic structure on the Raman spectra at 289 cm−1 and on FT-IR spectra around 430-580 cm−1. Electronic investigation performed by UV–Visible spectroscopy showed that the films have high absorbance in the visible region and their optical band gap increases from 2.40 to 2.66 eV (blue shift) with increasing annealing temperature from 350 to 550 °C.
Open Access
Theoretical analysis of the structural, electronic, optical and thermodynamic properties of trigonal and hexagonal Cs3Sb2I9 compound
(Université de M'sila, 2020) Saadi Berri
The structural, electronic, optical and thermodynamic properties of Cs3Sb2I9 compound with 0-D dimer form (hexagonal SP; P63=mmc, no. 194) and the 2-D layered form (trigonal SP; P3 m1, no. 164) phases have been investigated and reported using both FP-LAPW and PP-PW methods. Besides, the thermodynamic properties of the materials of interest have been studied using the quasi-harmonic Debye model accommodating the lattice vibrations e ects. The obtained lattice parameters for dimer and layered phase reveal very good accord with experiment. The computed electronic band structures show that in the dimer phase the material of interest is an indirect band-gap (k{􀀀) semiconductor, whereas it is a direct band-gap (􀀀{􀀀) in the layered phase. The semiconducting material Cs3Sb2I9 of interest was found to be stable against volume change of 0 to +14%. Moreover, the optical properties of the material in question are also examined and discussed. The e ect of pressure and temperature on the studied properties is found to be highly e ective in tuning some of the macroscopic properties of the compound in question
Open Access
A New Configuration of Vertically Connecting Solar Cells: Solar Tree
(Université de M'sila, 2020) Anouar Bella Baci; Mohamed Salmi; Younes Menni; Samira Ghafourian; Milad Sadeghzadeh; Mohammad Ghalandari
Copyright © 2020 Anouar Bella Baci et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Solar energy is a renewable type, clean, and inexhaustible which is suﬃciently available on the Algerian territory. The energy received daily on a horizontal surface of 1 m2 is in the order of 5 kWh over almost the whole Algerian territory; the duration of sunshine surpasses 2000 hours annually and can reach 3900 hours on the highlands and the Sahara. The importance of this work is based on exploiting solar energy to produce electricity. This study is based on the experimental exploitation of solar energy using solar tree’s prototype suggestion. This new model is focused to replace the leaf of a tree by the solar cell, starting by examining the solar ﬁeld and physical phenomenon related with it; the description of cell photovoltaic comes after; and ﬁnally, the dimension of the solar system and the experimental studies are virtually released in the University of M’sila. In this work, a prototype of new artiﬁcial solar tree is proposed experimentally by using material available in the local market: 25 solar panels, metal support, electrical queues, regulator, and battery. The results highlight a power improvement in the case of the proposed new model (solar tree) compared to the traditional one provided (solar panel), for the speciﬁed time range between 8 am and 2:30 pm. On the other hand, the traditional model values improve if the time dimension is extended from 2:30 pm to 6:00 pm. This is due to the temperature of the region and the presence of interstellar spaces between the cells of the solar tree.
Open Access
Experimental and theoretical studies on structural, morphological, electronic, optical and magnetic properties of Zn1-xCuxO thin films
(2021) Elhadj Benrezgua; Bahri Deghfel; Abdelhafid Mahroug; Muhamad Kamil Yaakob; Ammar Boukhari; Rabie Amari; Soorathep Kheawhom; Ahmad Azmin Mohamad
Pure and copper-doped zinc oxide thin films at different contents x (Zn1-xCuxO; 0≤x ≤ 0.125) were synthesized by sol–gel spin coating process and investigated using various techniques. All samples exhibited a polycrystalline with wurtzite hexagonal phase, which wasn't altered and getting relaxed by Cu-doping. The grain size increased and changed its growth mode from c-axis growth to lateral one and the surface morphology was strongly influenced with increasing level of Cu doping. As x increased, the transparency of films was generally increased in the visible region and the band gap energy (Eg) presented a slight shrinking, indicating that the prepared films are suitable for use in opto-electronic applications. Ferromagnetic phase was adopted within density functional theory corrected by Hubbard method (DFT+LDA+U) to investigate the structural, electronic, magnetic and optical properties of pure and CZO structure. The closest Cu impurities gave the more stable configuration. Cu3d states were distributed around Fermi level inducing a major contribution to the magnetic moment. A mix of ionic and covalent bonding was remarked. DFT + LDA + U enhanced significantly the calculated Eg, which presented a narrowing with x. The imaginary part of the dielectric functions presented three main peaks and their static constants were slightly influenced by Cu doping.