Annaba, Algeria
Annaba, Algeria

The Badji Mokhtar University , also called Annaba University or UBMA, is located in Annaba, on the north eastern coast of Algeria.It is founded in 1975 and is organized into 7 faculties. Wikipedia.

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Attoui I.,Welding and Research Center | Omeiri A.,Annaba University
Energy Conversion and Management | Year: 2014

In this paper, a contribution to modeling and fault diagnosis of rotor and stator faults of a Self-Excited Induction Generator (SEIG) in an Isolated Wind Energy Conversion System (IWECS) is proposed. In order to control the speed of the wind turbine, while basing on the linear model of wind turbine system about a specified operating point, a new Fractional-Order Controller (FOC) with a simple and practical design method is proposed. The FOC ensures the stability of the nonlinear system in both healthy and faulty conditions. Furthermore, in order to detect the stator and rotor faults in the squirrel-cage self-excited induction generator, an on-line fault diagnostic technique based on the spectral analysis of stator currents of the squirrel-cage SEIG by a Fast Fourier Transform (FFT) algorithm is used. Additionally, a generalized model of the squirrel-cage SEIG is developed to simulate both the rotor and stator faults taking iron loss, main flux and cross flux saturation into account. The efficiencies of generalized model, control strategy and diagnostic procedure are illustrated with simulation results. © 2014 Elsevier Ltd. All rights reserved.

Ben Ali Y.M.,Annaba University
Applied Intelligence | Year: 2012

This paper proposes a novel approach to swarm particle optimization based on emotional behavior to solve real optimization problems. In the trend of PSO manipulating self-adaptive control to regulate potential parameters, the proposed algorithm involves both a semi-adaptive inertia weight and an emotional factor at the level of the velocity rule. The semi-inertia weight highlights a specific comportment. Thus, due to the few changes occurred in its adaptive "life", it continues to evolve with a significantly smaller constant for the benefit of a finer exploitation. The emotion factor presents an important feature of convergence because it splits up the search space into potential regions that are finely explored by sub-swarm populations with the same emotions. The principle of particles with multiple emotions intended for the categorization of particles into specific emotional classes. The idea behind this principle is to divide to conquer, and due to presence of multiple emotional classes the multidimensional search space is widely explored at the search of the best position. Emotional PSO is evaluated on the test suit of 25 functions designed for the special session on real optimization of CEC 2005, and its performances are compared to the best algorithm the restart CMA-ES. © 2011 Springer-Verlag.

Nourredine A.,Annaba University
Bulletin of Materials Science | Year: 2011

Glass fibres in concrete material often increase the flexural strength. However, these fibres when in contact with cement are altered by alkali reactions due to the presence of portlandite. This study presents the results of investigation to show the effect of curing conditions on the durability of alkali-resistant glass fibres in cement matrix. Test results show that even alkali resistant fibres treated with zirconium oxide present the same degradation phenomenon. They also show that the nature of the cement has a large influence on the protection of the fibres: the Portland CEM II is less damaging than the CEM I. The substitutions of a part of cement by silica fume gave no substantial improvements to the mechanical strength of the glass fibre reinforced cement (GFRC). However, the observed microstructures in the samples show that the degradation is weakened with the addition of silica fumes. The analytical techniques used in this study are scanning electron microscope (SEM) and X-ray diffraction. © Indian Academy of Sciences.

Ydri B.,Annaba University
Journal of High Energy Physics | Year: 2014

We propose a new algorithm for simulating noncommutative phi-four theory on the fuzzy sphere based on, i) coupling the scalar field to a U(1) gauge field, in such a way that in the commutative limit N → ∞, the two modes decouple and we are left with pure scalar phi-four on the sphere, and ii) diagonalizing the scalar field by means of a U(N) unitary matrix, and then integrating out the unitary group from the partition function. The number of degrees of freedom in the scalar sector reduces, therefore, from N 2 to the N eigenvalues of the scalar field, whereas the dynamics of the U(1) gauge field, is given by D = 3 Yang-Mills matrix model with a Myers term. As an application, the phase diagram, including the triple point, of noncommutative phi-four theory on the fuzzy sphere, is reconstructed with small values of N up to N = 10, and large numbers of statistics. © 2014 The Author(s).

Lahoubi M.,Annaba University
Journal of Physics: Conference Series | Year: 2016

The specific heat Cp(T) and entropy S(T) properties of the orthorhombic PrBa2Cu3O6+x compounds in two states of oxygen concentration x, an over doped (OV) with x = 1 and an optimally doped (OP) with x = 0.95 are reanalyzed below the Néel temperature of the antiferromagnetic ordering of the Pr sublattice T N = 17.5 and 14 K, respectively. Two simultaneous anomalies for both states are observed. The first one occurs near the previous spin reorientation phase transition temperature T 2 ∼ 11.5 and ∼ 9-10 K, respectively whereas the second one remains close to the so called low-critical temperature Tcr ∼ 4-5 K for the OV state as it has been reported before for the OP state. By fitting the C p(T)/T data to A{T 2}-3/2 + γ + C{T 2}1 + D{T1}2 for T < T cr the four coefficients obtained with the best adjusted A-squared values are compared with previous findings. Reduced values for y are confirmed in this work. The results which are well described by the contribution of the DT 5 term to Cp(T) can be connected with the previous Pr-Cu(2) magnetic coupling that is sufficiently enough to cause a modest spin reorientation phase transition at T2 and a critical magnetic behaviour below Tcr . © Published under licence by IOP Publishing Ltd.

Triki H.,Annaba University
Romanian Journal of Physics | Year: 2014

In this work, a dissipation-modified Korteweg-de Vries (KdV) equation is considered. The equation is relevant to describe, for instance, nonlinear Bénard-Marangoni oscillatory instability in a liquid layer heated from above. In particular, the model with time-dependent coefficients required for the case of inhomogeneous media is studied. Periodic solutions and soliton solutions of this equation are obtained using the sinecosine and solitary wave ansatz methods. Parametric conditions for the existence and uniqueness of exact solutions are presented. These analytical findings may be of significant importance for the explanation of physical phenomena arising in nonlinear systems described by the dissipation-modified KdV-type equations.

The feasibility of using loquat seeds (LS) for the sorption of Rhodamine B (RhB) from aqueous solutions has been investigated in the absence and presence of ultrasound and by combining concurrently ultrasonic irradiation and mechanical stirring. Batch sorption studies were conducted to study the effects of various parameters such as sorbent dose, initial dye concentration and ultrasonic power on RhB sorption. The obtained results show that both the rate and amount of RhB sorption were drastically improved in the presence of ultrasound. The dye sorption with the assistance of ultrasound was enhanced with the increase of sorbate initial concentration and ultrasonic power, and with the decrease of sorbent dosage. The simultaneous association of ultrasound and stirring leads to an intensification of the sorption. Equilibrium data were analyzed by the Langmuir, Freundlich and Redlich-Peterson models by using non-linear regression technique. The sorption equilibrium data were best represented by the Langmuir and Redlich-Peterson isotherms for the conventional and combined methods. In the presence of ultrasound alone, the Redlich-Peterson model yields a better fit than the Langmuir model. LS was shown to be an efficient sorbent for the removal of RhB from aqueous solutions. © 2010 Elsevier B.V.

Ydri B.,Annaba University
International Journal of Modern Physics A | Year: 2012

We present a study of D = 4 supersymmetric YangMills matrix models with SO(3) mass terms based on the Monte Carlo method. In the bosonic models we show the existence of an exotic first-/second-order transition from a phase with a well defined background geometry (the fuzzy sphere) to a phase with commuting matrices with no geometry in the sense of Connes. At the transition point the sphere expands abruptly to infinite size then it evaporates as we increase the temperature (the gauge coupling constant). The transition looks first-order due to the discontinuity in the action whereas it looks second-order due to the divergent peak in the specific heat. The fuzzy sphere is stable for the supersymmetric models in the sense that the bosonic phase transition is turned into a very slow crossover transition. The transition point is found to scale to zero with N. We conjecture that the transition from the background sphere to the phase of commuting matrices is associated with spontaneous supersymmetry breaking. The eigenvalues distribution of any of the bosonic matrices in the matrix phase is found to be given by a nonpolynomial law obtained from the fact that the joint probability distribution of the four matrices is uniform inside a solid ball with radius R. The eigenvalues of the gauge field on the background geometry are also found to be distributed according to this nonpolynomial law. © 2012 World Scientific Publishing Company.

Kara H.M.,Annaba University
European Journal of Wildlife Research | Year: 2012

Little is known about freshwater fish diversity in Algeria, especially after the broad national program of introduction of exotic species applied for over 20 years. This paper is an attempt to describe the current situation emphasizing the characteristics of the various introductions of non-autochthonous species, their current status and their possible impacts. The freshwater fish fauna of Algeria is composed of 48 species belonging to 15 families. Twenty-one species are autochthonous, of which, three are endemic (Haplochromis desfontainii, Aphanius saourensis, Aphanius apodus), two are endangered (H. desfontainii, Aphanius iberus), and one is critically endangered (Anguilla anguilla). Twenty-seven species were introduced, of which, 18 never became established and 9 are established. Four species are reported for the first time: Abramis brama, Aspius aspius, Carassius carassius, Perca fluviatilis. Since 1860, 303 introduction events have been recorded at almost 107 different sites in Algeria. The number of introduction events per site was between 1 and 10. Most of the introduced fish are found in Oubéïra Lake (seven species). Aquaculture development was the main reason for fish introductions (37.0%). The five most often introduced species were Cyprinus carpio (86 records), Hypophthalmichthys molitrix (65 records), Aristichthys nobilis (51 records), Oreochromis niloticus niloticus (33 records), and Ctenopharyngodon idella (18 records). Since the adverse effects of introduced fish are risky and demonstrated in several countries, the adoption of the precautionary principle is recommended when new introductions are planned. It is important, therefore, to adopt regulations and procedures which will minimize the risks arising from introductions. © 2011 Springer-Verlag.

Ourici A.,Annaba University
International Journal of Electrical Power and Energy Systems | Year: 2012

In this article, a new vector control intended for an induction motor in double fed mode is proposed. It is based on the principle of a double flux orientation of stator and rotor at the same time. Therefore, the orthogonality created between the two oriented fluxes, which must be strictly observed, leads to generate a linear and decoupled control with an optimal torque. The obtained simulation results show the feasibility and the effectiveness of the suggested method. © 2012 Elsevier Ltd. All rights reserved.

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