مقـــــــــالات 2010-2015
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Item Stable indirect fuzzy adaptive control(Elsevier, 2003) Goléa, N.; Goléa, A.; Benmahammed, K.This paper investigates new fuzzy model-based observer adaptive control for multi-input multi-output continuous-time nonlinear systems. The proposed adaptive scheme uses Takagi–Seguno (TS) fuzzy models to estimate the plant states and dynamics. Using stability arguments, it is shown that the proposed scheme is globally asymptotically stable. The observation and tracking errors are shown to converge asymptotically to zero, despite the presence ofexternal disturbances and approximation errors. The performance ofthe developed approach is illustrated, by simulation, on two-link robot model.Item Observation ofMeyer–NeldelruleinCdSthinfilms(Elsevier, 2011) Hariech, S; Aida, M.S; Moualkia, HA study of electrical transport in CdS thin films is reported. We have observed, for the first time, that CdS thin film conductivity obeys the Meyer–Neldel rule (MNR). This was deduced from linking the conductivity pre-exponential factor to the activation energy variation. CdS films were deposited by chemical bath deposition at different solution temperatures in order to vary the electrical activation energy of the films. A correlation between the MNR rule and the disorder in the film network is highlighted. The multi- trapping process in the band tail-localized states governs the conductivity in CdS films. This explains the MNR observation in CdS films. The variation of the electrical conductivity pre-exponential factor and activation energy are correlated to the disorder in the film network; this was explained in terms of polaron formation and phonon– electron coupling with disorder.Item LLE for the extraction of alcohol from aqueous solutions with diethyl ether and dichloromethane at 293.15 K, parameter estimation using a hybrid genetic based approach(Elsevier, 2011) Merzougui, A; Hasseine, A; Kabouche, A; Korichi, MExperimental liquid–liquid equilibrium (LLE) data for the extraction of methanol, ethanol and 1-propanol from water by diethyl ether and dichloromethane at 293.15 K and at ambient pressure were investigated. Data for the binodal curves have been determined by cloud-point titration method and conjugate points on tie-line were obtained by correlating the refractive index of the binodal curves as a function of composition. The experimental ternary (liquid + liquid) equilibrium data have been estimated using the NRTL and UNIQUAC activity coefficient models to obtain the binary interaction parameters of these components by a combination of Levenberg–Marquardt method and the genetic algorithm based method. Thedistribution coefficients and the selectivity factor of the solvent used were calculated and presented. From our experimental and calculated results, we conclude that for the extraction of alcohol from aqueous solutions with dichloromethane solvent has a higher selectivity factor than the diethyl ether solvent.Item Chemical constituents of the roots of Algerian Bunium incrassatum and evaluation of its antimicrobial activity(Elsevier, 2011) Bousetla, Ahlem; Zellagui, Amar; Derouiche, Kamel; Rhouati, SalahIn this study we investigated the chemical composition of the roots of Bunium incrassatum growing in Algeria, two coumarins, b-sitosterol, sucrose and oleic acid were isolated from methylene chloride:methanol (1/1) extract of the roots of this species. Furthermore, antimicrobial activity of the crude extract was evaluated using agar diffusion method. The antimicrobial results showed that the crude extract had a great potential antimicrobial activity against all the test microorganisms especially fungal strains.Item International Conference on Education and Educational Psychology (ICEEPSY 2011)(Elsevier, 2011) Merrouche, SarahThough many schools and universities are today connected to the Internet, its technologies are still not adequately integrated into classroom teaching and learning. Many teachers think in rather restricted ways about using online tools and resources in their profession. This paper attempts to shed light on the MOO (Multi-User Domain – Object Oriented) technology, which provides a flexible and rich virtual environment for synchronous communication. Focus is laid on the Da-MOO, or the Educational MOO, and the way it lends itself to collaborative learning, particularly tandem learning, to support teaching in the language classroom. A practical experience with “The Palace” is described. Algerian EFL students find it appealing, motivating and useful.Item Solar drying of wastewater sludge(Elsevier, 2011) Bennamoun, LyesDrying constitutes an important process for wastewater sludge management, as it can reduce the mass and the volume of the product and consequently the cost of storage, handling and transport. During constant operating conditions, the drying kinetic of the sludge has shown mainly: a constant drying rate, one or two falling rate periods and a final short period with variations along the process of the physical properties of the product with the appearance of shrinkage and cracks phenomena. Solar drying was benefit as using free solar energy can reduce the cost of the operation. On the other hand, it plays an important role for the pathogen reduction until Environmental protection Agency (EPA) recommendations. In some studied cases, the value of 1000 CFU g−1 DS, which represents the EPA Class A pathogen requirement, for fecal coliform was attained. The general design of used solar dryers was constituted of: a greenhouse made with transparent material and a floor, where the product is speared in thick layers. Furthermore, fans and ventilations can be used in order to have homogeneous distribution of the air inside the greenhouse with replacement of humidified air with fresh one. Automatic or handle mix of the product was used once or for several times a day. In order to increase the performances of the drying system, other ways such as heating the floor using solar water heater, infrared lamps, using heat pumps or adding thermal energy storage systems were also tested. Covered solar drying has given better results than open solar drying. However, the origin of the wastewater sludge affects the obtained results. Alternatively, modeling drying systems was effectuated using heat and mass balances, applied for the air and the dried product. Solar drying of wastewater sludge has given satisfactory results.Item Reviewing the experience of solar drying in Algeria with presentation of the different design aspects of solar dryers(Springer, 2011) Bennamoun, LyesSolar drying is one of the processes that have found application in Algeria, because of the important quantities of solar irradiations that can be exploited in this country. Nevertheless, the experience of Algeria in solar drying is recent and limited to drying of fruits, vegetables, medicinal and aromatic herbs. The effectuated review has given an idea about the existing functional dryers in this country with presentation of their different design aspects and in some cases the mathematical modeling for well describing and predicting their behaviours. The solar dryers were classified into two classes according to their operation mode and without taking into account if the dryers are using auxiliary sources of energy. The two classes are: passive dryers and active dryers. On the other hand, each class was divided into subclasses representing the type. We have found the direct and indirect types for the passive dryers, but only indirect types for the active dryers. Mixed types were not developed. The solar dryers were developed and tested in two different climatic regions which are the north of the country and the Sahara. In the most studied cases, one or multiple auxiliary sources of energy were used in order to increase the performances of the dryer or to decrease drying time. Consequently, we register the utilization of pebbles as a heat storage system, resistances as electrical heater, gas-ring and photovoltaic cells in order to give independency against the use of the traditional electrical energy. In the case of the active dryers, adding fans and temperature and flow controllers has permitted the control of the drying conditions. Depending on the dryers, the dried quantities vary from 200 g to 36 kg. Comparison between many studied cases for different modes and types and with open sun drying method was furthermore done. With a few exceptions to some solar dryers which present problems of complexity and was not practical and easy for manipulation to the agricultural producer, the majority of the developed solar dryers have presented satisfactory resultsItem Recursive prediction error identification of fractional order models(Springer, 2011) Djouambi, Abdelbaki; Voda, Alina; Charef, AbdelfatahThis paper deals with time domain identification of fractional order systems. A new identification technique is developed providing recursive parameters estimation of fractional order models. The identification model is defined by a generalized ARX structure obtained by discretization of a continuous fractional order differential equation. The parameters are then estimated using the recursive least squares and the recursive instrumental variable algorithms extended to fractional order cases. Finally, the quality of the proposed technic is illustrated and compared through the identification of simulated fractional order systems.Item An observer based backstepping control for a greenhouse(2011) Belhani, Ahmed; M’sirdi, Nacer KouiderIn this paper we use the backstepping approach to control climate parameters of greenhouse. To get realistic simulation, we use real weather data collected in the south region of Algeria (Biskra). We control temperature, relative humidity and CO2 concentration by acting on four variables such as heating, ventilation, CO2 injection and water injection. However as the CO2 sensors is not available, we use an nonlinear observer based on temperature and steam density measurements, To get an optimal controller, the multi- objective genetic algorithms based on Non dominated Sorting Genetic Algorithms (NSGA) techniques and Multi-Criteria Decision Analysis (MCDA) approach are introduced.Item Combining neural networks for arabic handwriting recognition(IEEE, 2011) Chergui, Leila; Kef, Maâmar; Chikhi, SalimCombining classifiers is an approach that has been shown to be useful on numerous occasions when striving for further improvement over the performance of individual classifiers. In this paper we present an off-line Multiple Classifier System (MCS) for Arabic handwriting recognition. The MCS combine two individual recognition systems based on Fuzzy ART network used for the first time in Arabic OCR, and Radial Basis Functions. We use various feature sets based on Hu and Zernike Invariant moments. For deriving the final decision, different combining schemes are applied. The best combination ensemble has a recognition rate of 90,1 %, which is significantly higher than the 84,31% achieved by the best individual classifier. To demonstrate the high performance of the classification system, the results are compared with three research using IFN/ENIT database.Item Nonlinear integral backstepping control for induction motors(İstanbul - Turkey, 2011) Mehazzem, F.; Nemmour, A.L; Benalla, H.A novel structure of nonlinear integral backstepping control has been proposed for induction motors. We can see clearly that the structure of the controller generated by the classical version of backstepping is composed of a proportional action, which was added a derivative action on errors. Such a structure makes the system sensitive to measurement noise. The lack of integration means also the appearance of a constant static error, caused mainly by non-zero mean disturbances. The solution t o this p roblem i s to d esign a n ew v ersion of the backstepping with integral action. By using the proposed integral backstepping controller, the system has a better load disturbance rejection capability. The effectiveness of this proposed control structure is verified by simulation as well as by experiment under critical disturbance conditions.Item A Detailed Chemical Kinetic Mechanism for Methanol Combustion in Laminar Flames1(Pleiades Publishing, 2011) Hamdane, S; Rezgui, Y; Guemini, MOn the basis of existing detailed kinetic schemes a general and consistent mechanism of the oxi dation of methanol was compiled for computational studies covering a wide range of lean to rich flames. The proposed model, featuring 21 species and 115 reactions, has been validated using three data sets and the com puted reactants, products and intermediates mole fractions. This scheme was compared to those by Held⎯Dryer, Egolfopolous and Pauwels under the same conditions. The developed mechanism predicts well the concentrations of the major reactants, intermediates, and products at all the studied equivalence ratios and it gives the best calculated values, as compared to the other used models, as well. The production rates analysis of selected species allowed the identification of the major formation and depletion pathways. A reac tion path analysis snowed that the main channels in methanol consumption involved H, OH and O attack and the resulting radicals CH2OH and CH3O produced formaldehyde.Item Fixed points and lines in 2-metric spaces(Elsevier, 2012) Aliouche, AbdelkrimWe consider bounded 2-metric spaces satisfying an additional axiom, and show that a contractive mapping has either a fixed point or a fixed line.Item Chemical composition and antibacterial activity of the essential oils from Launaea resedifolia L(Springer, 2012) Zellagui, Amar; Gherraf, Noureddine; Ladjel, Segni; Hameurlaine, SamirBackground: Several species of the genus Launaea are used in folk medicine such as in bitter stomachic, skin diseases, and reported to have antitumor, insecticide, and cytotoxic activities. The antimicrobial activities of coumarin constituents and the neuropharmacological properties have been investigated as well. In this study, the chemical composition of essential oils from Launaea resedifolia L. has been identified using the ordinary GC-MS technique to reveal the presence of 19 compounds dominated by dioctyl phthalate. Moreover, the antibacterial activity of the crude oil has been carried out using disk diffusion method against seven bacteria strains. Results: Nineteen compounds of essential oil of L. resedifolia L. were identified, representing 86.68% of the total oil. The compounds were identified by spectral comparison to be mainly esters, alcohols, ketones, and terpenes. The principal constituents are dioctyl phthalate (39.84%), Decanoic acid, decyl ester (12.09%), 11-Octadecenal (11.24%), and Eucalyptol (07.31%), while others were present in relatively small amounts. As far as antibacterial essays are concerned, it was found that the oils are active against most of the tested bacterial strains. Conclusion: A major constituent in visible parts was Dioctyl phthalate (39.84%) and the yield of essential oils was 0.9%. These extracts reveal in vitro antibacterial activity on the studied bacterial, confirmed by the inhibition zone diameter ranging from 11 to 37 mm and a MIC value between 0.09 and 0.69 depending on the microorganism being tested.Item Interaction parameter estimation in liquid–liquid phase equilibrium modeling using stochastic and hybrid algorithms(Elsevier, 2012) Kabouchea, A.; Boultif, A.; Abidib, A.; Gherraf, N.Metaheuristic methods Simulated annealing (SA) and Genetic algorithm (GA) combined with hybrid functions were investigated to estimate interactions parameters in liquid–liquid phase equilibrium systems. The Rastrigin and Rosenbrock functions with high number of variables were used as test functions to compare the performance of each algorithm. The experimental ternary LLE data for extraction of alcohol with dichloromethane (and diethyl ether) were considered in the NRTL and UNIQUAC activity coefficient model. The interaction parameters were carried out taking into account the closure equation. As a main conclusion, Hybrid algorithms have showed the best performance to estimate the interaction parameters comparatively to stochastic and deterministic algorithmsItem Effects of heat treatment and TiO2 content on the optical properties of Eu3+ doped TiO2–SiO2 thin films(Elsevier, 2012) Berkani, Oualid; Latrous, Khelil; ElHamzaoui, Hicham; Capoen, Bruno; Bouazaoui, MohamedThe photoluminescence properties of Eu3+- doped TiO2–SiO2 thin films were investigated.The films were deposited on silicon substrates by thesol–gel process using the dip-coatingmethod.Themolar ratio ofTiO2 content was varied from25%to100%,while Europium concentration was fixed to1%.The obtained films were calcinatedatvarioustemperaturesrangingfrom400 1C to1300 1C, whichallowed determiningtheoptimalconditionsfortheEu3þ luminescence.Meanwhile,thestructureofTiO2–SiO2 powders,preparedinthesameconditionsasthefilms,wasalsostudiedbyRamanspectroscopy. It revealedtheroleofEuropiumandSiO2 on thestabilizationoftheanatasephaseandtheimportance of thesilicamatrixinthecontroloftitaniaparticlesizeItem Effect of Al Substitution on Structural and Electrical Properties of Bi1.6Pb0.4Sr2CaCu2−xMxO8+δ Superconducting Ceramics(Springer, 2012) Bouaïcha, F.; Mosbah, M.-F.; Hamel, M.; Benmaamar, F.In this work we study the effect on structural and electrical properties of superconducting compound Bi1.6Pb0.4Sr2CaCu2−yMyO8+δ were M = Al (with y = 0–0.6). The samples were prepared by the solid-state reaction method. The samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), direct current (DC) resistivity versus temperature ρ(T ) and alternative current (AC) susceptibility measurements. Structural analysis shows that the crystalline lattice structure of the prepared sample belongs, mainly, to the superconduc- tive tetragonal phase Bi(Pb)2212. The SEM micrographs show that in the undoped sample the grain size has a random distribution with few grains greater than 5 μm. The grains are very dense and well connected. A quite different microstructure is obtained for the doped samples of which grains are more connected with a flat characteristic shape of Bi(Pb)2212 superconductors. All samples exhibit a superconducting character and Tc and the superconducting volume fraction decrease with increasing rate of aluminum.Item Comments on the height reducing property II(Elsevier, 2012) Akiyamaa, Shigeki; Thuswaldner, J¨org M.; Zaimi, ToufikA complex number α is said to satisfy the height reducing property if there is a finite set F ⊂ Z such that Z[α] = F[α], where Z is the ring of the rational integers. It is easy to see that α is an algebraic number when it satisfies the height reducing property. We prove the relation Card(F) ≥ max{2, |Mα(0)|}, where Mα is the minimal polynomial of α over the field of the rational numbers, and discuss the related optimal cases, for some classes of algebraic numbers α. In addition, we show that there is an algorithm to determine the minimal height polynomial of a given algebraic number, provided it has no conjugate of modulus one. ⃝c 2014 Royal Dutch Mathematical Society (KWG). Published by Elsevier B.V. All rights reserved.Item Chemical composition and antibacterial activity of the essential oils of Ferula vesceritensis Coss et Dur. leaves, endemic in Algeria(Springer, 2012) Zellagui, Amar; Gherraf, Noueddine; Rhouati, SalahBackground: The biological importance of members of genus Ferula promoted us to investigate the leaves of Ferula vesceritensis Coss et Dur. (endemic plant) previously not investigated. This study presents the chemical composition and antibacterial activities of the hydrodistilled oils. Results: Volatile components of the leaves of F. vesceritensis have been studied by gas chromatography–mass spectrometry to afford 23 compounds. The major components were found to be 5,9-tetradecadiyne (24.72%), germacrene D (24.51%), farnesene (8.57%), and α-bisabolene (8.57%). The antimicrobial activities of the essential oils were evaluated by disk diffusion method and tested against Gram-positive and Gram-negative bacteria. The volatile oil showed a strong antibacterial activity against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia. Conclusions: These results reinforce the previous studies showing that the genus Ferula is considered as a good source of essential oils. The results presented here can be considered as the first information on the antimicrobial properties of F. vesceritensis.Item On the distribution of certain Pisot numbers(Selsevier, 2012) Zaimi, ToufikA Pisot number θ is said to be simple if the beta-expansion of its fractional part, in base θ, is finite. Let P be the set of such numbers, and S \ P be the complement of P in the set S of Pisot numbers. We show several results about the derived sets of P and of S \P. A Pisot number θ, with degree greater than 1, is said to be strong, if it has a proper real positive conjugate which is greater than the modulus of the remaining conjugates of θ. The set, say X, of such numbers has been defined by Boyd (1993) [5], and is contained in S \ P. We also prove that the infimum of the j -th derived set of X, where j runs through the set of positive rational integers, is at most j + 2. ⃝⃝c 2012 Royal Dutch Mathematical Society (KWG). Published by Elsevier B.V. All rights reserved.