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Algiers, Algeria

The University of Science and Technology – Houari Boumediene is a university located in the town of Bab-Ezzouar 15 kilometres from Algiers, Algeria. The university was designed by Brazilian architect Oscar Niemeyer and was inaugurated in 1974.Courses offered include Computing, Pure and Applied Mathematics, Physics, Chemistry, Biology, Geology, Civil Engineering, Electronics, Information Technology, Process Engineering, and Mechanical Engineering. USTHB was the largest university in Algeria until 2013; it has over 20,000 students. The government five-year plan aiming at raising the number of university students in Algeria from 1.2 million in 2010 to 2 million students in 2014 has led to the construction of new universities and faculties in almost every Algerian town; some universities are now larger than the USTHB in the number of enrolled student. The USTHB has all the facilities required in modern university. The USTHB collaborate tightly with western universities, especially with French universities, agreements exist between the faculties and their counterpart in France, Quebec Canada and other countries for the purpose of training and research. A number of Arab and African student receive grants to study in the USTHB.All the programs are provided in French language, except for the Geography curriculum that is provided in Arabic language. Wikipedia.

Keddam M.,University of Science and Technology Houari Boumediene
Applied Surface Science

The present work is an attempt to simulate the growth kinetics of the (FeB/Fe2B) bilayer grown on a substrate made of AISI 316 stainless steel by the application of the powder-pack boriding process, and using four different temperatures (1123, 1173, 1223 and 1273 K) and five exposure times (2, 4, 6, 8 and 10 h). The adopted diffusion model solves the mass balance equation at each growth front: (FeB/Fe2B or FeB/substrate) under certain assumptions and without considering the diffusion zone. To consider the effect of the incubation times for the borides formation, the temperature-dependent function φ(T) was incorporated in the model. To validate this model, a computer code written in Matlab (version 6.5), was developed with the purpose of simulating the kinetics of the boride layers. This computer code uses the following parameters as input data: (the boriding temperature, the treatment time, the upper and lower limits of boron concentration in each iron boride, the diffusion coefficients of boron in the FeB and Fe2B phases as well as the φ(T) parameter). The outputs of the computer code are the parabolic growth constant at each growth front and the thicknesses of the FeB and Fe 2B layers. A good agreement was obtained between the experimental parabolic growth constants taken from a reference work [I. Campos-Silva et al., Formation and kinetics of FeB/Fe2B layers and diffusion zone at the surface of AISI 316 borided steels, Surf. Coat Technol., 205 (2010) 403-412] and the simulated values of the parabolic growth constants (kFeB and k1). The present model was also able to predict the thicknesses of the FeB and Fe2B layers at a temperature of 1243 K during 3 and 5 h. In addition, the mass gain at the material surface was also estimated as a function of the time and the upper boron content in each iron boride phase. It was shown that the simulated values of the generated mass gain are very sensitive to the increase of both temperature and the upper boron contents in the FeB and Fe2B phases. © 2010 Elsevier B.V. All rights reserved. Source

Abdi A.,Polytechnic School of Algiers | Trari M.,University of Science and Technology Houari Boumediene
Electrochimica Acta

The hematite α-Fe2O3 is prepared by sol-gel route at 900 C. Structural and morphological characterizations are investigated by X-ray diffraction and scanning electron microscopy. The SEM image shows a monophasic structure with a chemical composition uniformly distributed, based on sintered agglomerates particles with no particular orientation. The EDS characterization shows wide non-stochiometry (O/Fe = 0.72). The X-ray diffraction indicates an orthorhombic crystalline structure with an average crystallite size of 87 nm and a surface specific area of 13.3 m2 g-1. The hematite exhibits n-type conduction with direct (1.99 eV) and indirect (1.75 eV) optical transitions. The electrochemical properties are investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant charge-discharge methods in Na2SO3 (1 M) and NaOH (1 M) electrolytes. The CV characteristics show a typical pseudo-capacitive electrode behavior, associated with a faradic mechanism. The electrochemical impedance spectroscopy carried out over the frequency range (1 mHz-100 kHz) exhibits a dominant pseudo-capacitive behavior at low frequencies. The pseudo-capacitive phenomenon is preceded by diffusion process, implying a blocking behavior at high frequencies. The super capacitive properties of Fe2O3 at a scan rate of 5 mV s-1 show a maximum super capacitance of 4.915 and 48.21 F g-1 in NaOH and Na 2SO3, respectively. A typical charge-discharge behavior at 5 mA over a potential window of 1.2 V is obtained with coulombic efficiency approaching 100% in both electrolytes. © 2013 Elsevier Ltd. Source

Yeddou-Mezenner N.,University of Science and Technology Houari Boumediene

This study focuses on the possible use of Waste P. mutilus to remove Basic Blue 41, cationic dye from aqueous solutions. Batch kinetic studies were carried out as a function of pH, particle size, biomass amount and dye concentration to determine the decolorization efficiency of biosorbent. The highest dye removal yield was achieved at pH 8-9. Equilibrium occurred within about 60 min. The pseudo-second order kinetic model adequately describes the kinetic data. The Langmuir, Freundlich and Tempkin models were used to describe the isotherm data; of which the Freundlich model described the isotherm data with high correlation coefficient (r2=0,994). The maximum monolayer biosorption capacity of biosorbent material was found as 111 mg/g. Also, it was observed that the intra-particle diffusion was not the only rate-controlling step. The adsorption mechanism may be partly a result of the ion exchange or complexation between the dye ions and function groups on dead biomass surface. Finally the proposed biosorbent was successfully used for the decolorization of BB41 in synthetic wastewater conditions. © 2010 Elsevier B.V. All rights reserved. Source

Sayoud H.,University of Science and Technology Houari Boumediene
Literary and Linguistic Computing

Author discrimination consists of checking whether two texts are written by the same author or not. In this investigation, we try to make an author discrimination between the Quran (The holy words and statements of God in the Islamic religion) and the Hadith (statements said by the prophet Muhammad). The Quran is taken in its entirety, whereas for the Prophet's statements, we chose only the certified texts of the Bukhari book. Thus, three series of experiments are done and commented on. The first series of experiments analyses the two books in a global form (the text of every book is analyzed as a unique big text). It concerns nine different experiments. The second series of experiments analyses the two books in a segmental form (four different segments of text are extracted from every book). It concerns five different experiments. The third series of experiments makes an automatic authorship attribution of the two books in a segmental form by employing several classifiers and several types of features. The sizes of the segments are more or less in the same range (four different text segments, with approximately the same size, are extracted from every book). It concerns two different experiments. This investigation sheds light on an old enigma, which has not been solved for 14 centuries: in fact, all the results of this investigation have shown that the two books should have two different authors. © The Author 2012. Published by Oxford University Press on behalf of ALLC. Source

Boussaid I.,University of Science and Technology Houari Boumediene | Lepagnot J.,University Paris Est Creteil | Siarry P.,University Paris Est Creteil
Information Sciences

Metaheuristics are widely recognized as efficient approaches for many hard optimization problems. This paper provides a survey of some of the main metaheuristics. It outlines the components and concepts that are used in various metaheuristics in order to analyze their similarities and differences. The classification adopted in this paper differentiates between single solution based metaheuristics and population based metaheuristics. The literature survey is accompanied by the presentation of references for further details, including applications. Recent trends are also briefly discussed. © 2013 Elsevier Inc. All rights reserved. Source

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