Mahroug A.,Msila University |
Mahroug A.,University of Mentouri Constantine |
Boudjadar S.,University of Mentouri Constantine |
Hamrit S.,Msila University
Materials Letters | Year: 2014
Undoped and Al-doped ZnO thin films have been deposited onto glass substrates by the sol-gel spin coating method and their structural and optical properties have been investigated. The XRD results showed that all films were crystallized under hexagonal wurtzite structure and presented a preferential orientation along the c-axis where the maximum crystallite size was found to be 25 nm for undoped film. The average transmittance of all films is over 95% in the visible region and the band gap energy increases from 3.25 to 3.29 eV with the increase of Al concentration. In addition to the vibrational modes from undoped ZnO, longitudinal optical (LO) mode in the Raman spectra was enhanced by the Al doping. Photoluminescence of the films showed an ultraviolet (UV) and defect related visible emissions like violet, blue and green. 3% Al doped ZnO film shows the best photocurrent properties. © 2014 Elsevier B.V.
Taloub D.,Msila University |
Beghidja A.,University of Mentouri Constantine
Energy Procedia | Year: 2011
This article is a study, which consists of developing and validating the method of finished differences applied on unstationary thermal conduction with source in a square form oven, and the result is a partial and differential equation with a parabolic type. (Equation presented) The method of finished differences is used to solve these equations. The obtained scheme has been solved by the iterative method of: GAUSS Seidel. © 2011 Published by Elsevier Ltd.
Chemachema M.,University of Mentouri Constantine |
Zeghlache S.,Msila University
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2015
In this paper, an output feedback linearization based controller is designed to stabilize the Twin Rotor Multi-input Multi-output System (TRMS), and make its beam track accurately a reference signal, or reach desired positions in 2 DOF. Only yaw and pitch angles are considered available for measurement. An observer, to estimate the remaining states, is coupled with feedback linearization technique in a two-stage procedure. In the first stage, propellers thrusts are considered as virtual control inputs that lead to a TRMS canonical model for which feedback linearization is applied straightforwardly. In the second stage, the motors torques and actual control input voltages are computed, respectively, by solving algebraic equations and inverting motors models. In the proposed approach, the coupling effects are maintained in controller derivation and so there is no need to decouple the TRMS into horizontal and vertical subsystems, as usually done in the literature. Exponential stability of the closed loop is guaranteed by using the second method of Lyapunov. To show the performance and the effectiveness of the proposed controller, simulation results are presented. © 2014, Springer Science+Business Media Dordrecht.
Loukriz A.,High School Polytechnic ENP |
Haddadi M.,High School Polytechnic ENP |
Messalti S.,Msila University
ISA Transactions | Year: 2015
Improvement of the efficiency of photovoltaic system based on new maximum power point tracking (MPPT) algorithms is the most promising solution due to its low cost and its easy implementation without equipment updating. Many MPPT methods with fixed step size have been developed. However, when atmospheric conditions change rapidly , the performance of conventional algorithms is reduced. In this paper, a new variable step size Incremental Conductance IC MPPT algorithm has been proposed. Modeling and simulation of different operational conditions of conventional Incremental Conductance IC and proposed methods are presented. The proposed method was developed and tested successfully on a photovoltaic system based on Flyback converter and control circuit using dsPIC30F4011. Both, simulation and experimental design are provided in several aspects. A comparative study between the proposed variable step size and fixed step size IC MPPT method under similar operating conditions is presented. The obtained results demonstrate the efficiency of the proposed MPPT algorithm in terms of speed in MPP tracking and accuracy. © 2015 ISA.
Khemissa M.,Msila University |
Mahamedi A.,Msila University
Applied Clay Science | Year: 2014
Urban areas of the wilaya of M'sila in Algeria nowadays experience a considerable development because of an unceasingly increasing demography, from where its extension towards virgin zones often less favorable than those already urbanized. This wilaya is located in a zone classified as semi-arid, whose geology comprises clayey formations characterized by a high variation of volume when the conditions of their equilibrium are modified (natural climatic phenomena due to a prolonged dryness, human activity by modification of the ground water level because of excessive pumping, configuration of constructions in their environment). This paper presents and analyzes the results of a series of normal Proctor compaction tests, methylene blue tests, California bearing ratio tests and undrained direct shear tests performed on Sidi-Hadjrès expansive overconsolidated clay treated with mixture of various cement and lime contents and compacted under the optimum Proctor conditions. These test results show that the geotechnical parameters values are concordant and confirm the bearing capacity improvement of this natural clay, which is translated by a significant increase in soil strength and its durability. However, the best performances are obtained for a mixt treatment corresponding to 8% cement and 4% lime contents. © 2014 Elsevier B.V.
Khemissa M.,Msila University
Geotechnical and Geological Engineering | Year: 2016
Oedometric and triaxial tests are very much used in soil mechanics. However, in spite of their frequency in the world, these tests present some limitations related to remolding due to sampling process and to implemented experimental procedures. These limitations contribute to decreasing the resistance and deformability mechanical properties of soils, which condition their limit and critical states behavior. This paper proposes four validity criteria of oedometric and triaxial test results (compressibility criterion based on the oedometric test results; consolidation, resistance and rigidity criteria based on the triaxial test results) to appreciate the disturbance of test specimens. Impact of the sample disturbance on the yield envelope of clayey soils according to these validity criteria is then analyzed. © 2016, Springer International Publishing Switzerland.
Naceri A.,Msila University
Applied Mechanics and Materials | Year: 2010
This paper considers the analysis of the mechanical behaviour of a laminate constituted of 12 layers of glass fiber fabric/epoxy resin conditioned at different relative humidities of 0, 60 and 96% at 60 °C. The analysing of the experimental results obtained of hygrothermal ageing on the mechanical response has permited to show that the influence of the moisture concentration on the ultimate mechanical properties becomes significant and important for the composite conditioned at relative humidity of 96% to the periods I and II (state of saturation and ageing). © (2010) Trans Tech Publications.
Benterki D.,BB University |
Benseridi H.,Ferhat Abbas University Setif |
Dilmi M.,Msila University
Advances in Applied Mathematics and Mechanics | Year: 2014
In this paper, a nonlinear boundary value problem in a three dimensional thin domain with Tresca's friction law is considered. The small change of variable z =x3/e transforms the initial problem posed in the domain We into a new problem posed on a fixed domain W independent of the parameter e. As a main result, we obtain some estimates independent of the small parameter. The passage to the limit on e, permits to prove the results concerning the limit of the weak problem and its uniqueness. © 2014 Global Science Press.
Mihoubi D.,Msila University
LMS Journal of Computation and Mathematics | Year: 2011
This paper presents an extension of a result by Guessarian and Niar to the framework of multitransition systems. In the case of a single process, Guessarian and Niar had shown that the set of fair computations of regular SCCS processes coincides with the class of ε-free ω-regular languages. Here, in the case of multitransition systems, we show essentially that the sets of fair computations on multitransition systems are strictly included in the class of ε-free ω-regular N-languages. The inclusions of these fair sets into the class of ε-free ω-regular N-languages are obtained by showing that the strict (respectively weak, strong) fair condition can be simulated by the Muller acceptance condition on multitransition systems. The strictness of the inclusions is obtained by exhibiting two counter-examples showing that the reverse is false, that is, not every ω-regular N-language is the set of fair computations of some multitransition system. © 2011 Author.
Zedam L.,Msila University
Iranian Journal of Fuzzy Systems | Year: 2013
In this paper, a fuzzy version of the analytic form of Hahn-Banach extension theorem is given. As application, the Hahn-Banach theorem for r-fuzzy bounded linear functionals on r-fuzzy normed linear spaces is obtained.