vol 02 N 02
Permanent URI for this collection
Browse
Recent Submissions
Item Effects Of Geometric Ratios And Fibre Orientation On The Natural Frequencies Of Laminated Composite Plates(University of Eloued جامعة الوادي, 2010-07-01) Attaf, B.; Bachene, M.The present investigation aims to examine the influence of geometric ratios and fibre orientation on the natural frequencies of fibre-reinforced laminated composite plates using finite element method based on Yang’s theory and his collaborators. The transverse shear and rotatory inertia effects were taken into consideration in the developed Fortran computer program. It has been shown that the use of first-order displacement field provides the same accuracy as higher-order displacement field when the number of elements representing the plate structure is increased (refined mesh). However, poor precision may appear for plates with high thickness-to-side ratio h/a (thickness/side length). This discrepancy limits the application of the developed theory to thick plates (h/a<0.5). The various curves show the evolution of the dimensionless frequency (*) versus fibre orientation angle () and illustrate the apparition of a “triple-point” phenomenon engendered by the increase of the plate aspect ratio a/b (length/width) for a specific value of h/a. This point defines the maximum natural frequency and the associated fibre orientation. Also, results show that for high and/or low aspect ratios, the triple-point phenomenon does not occur. This latter is rapidly reached for thick plates than thin plates when the plate aspect ratio a/b is progressively increased.Item Calculation Of Coefficient Of Sharing Octanol-water Of Organic Compounds Using Molecular Descriptors(University of Eloued جامعة الوادي, 2010-07-01) Souyei, B.A quantitative structure-property relationship (QSPR) study is carried out to develop correlations that relate the molecular structures of organic compounds to their Octanol- Water partition coefficients, Kow , using molecular descriptors. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate Kow. Such calculation gives us a model that gives results in remarkable correlation with the descriptors of blocks fragments of the atom-centered and functional groups (R2 = 0.949, δ = 0477) (R2 = 0.926,δ = 0,548) respectively.Item Integrated Management Of Water Resources In The Valley Of Oued-souf (algeria): Issues Fitness For A New Strategy(University of Eloued جامعة الوادي, 2010-07-01) Khechana, S.; Derradji, F.; Derouiche, A.This study designed to analyze and evaluate the results of trend scenarios of the strategy management of water resources used in the valley of Oued-Souf, who led the region to a truly dramatic situation and almost desperate: rise of groundwater and its adverse consequences. In terms of this work, we seek a model (plan) for the development of these resources according to criteria of sustainability, and will take into account socio-economic and ecosystem aspect. That by adaptation and implementation of integrated management of water resources (IMWR) in this unit of water resources, to meet the needs of decision support in water management, so as to guide and mobilize progressive human resources, information, financial and material, as well as various private and public sectors towards finding concrete and measurable results of water and ecosystems.Item Application Of A Particle Swarm Optimization In An Optimal Power Flow(University of Eloued جامعة الوادي, 2010-07-01) Ben Attous, D.; Labbi, Y.In this paper an efficient and Particle Swarm Optimization (PSO) has been presented for solving the economic dispatch problem. The objective is to minimize the total generation fuel and keep the power outputs of generators; bus voltages and transformer tap setting in their secure limits. The conventional load flow and incorporation of the proposed method using PSO has been examined and tested for standard IEEE 30 bus system. The PSO method is demonstrated and compared with conventional OPF method (NR, Quasi Newton), and the intelligence heuristic algorithms such ac genetic algorithm, evolutionary programming. From simulation results it has been found that PSO method is highly competitive for its better general convergence performance.Item Contribution To The Experimental Study Of The Hydraulic Jump Evolving In An U-shaped Channel, With Rough Bed(University of Eloued جامعة الوادي, 2010-07-01)This study aims to investigate the threshold-controlled hydraulic jump, moving in channel profile 'U' fully rough for a single roughness value = 7,14 mm. Functional relations in dimensionless terms, linking the different characteristics of the jump, showing the effect of bottom friction channel, are obtained as: y2= (-14,19y1 + 6, 42) Q*; y2= 1,13y10,65 exp [0,95y10,61.s/h1] . The method is as follows: we vary the flow volume by manipulating the valve and their measurements are read directly on the meter display éctronique. Supply channel is by means of a pump flow up 40 l / s. The flume was designed in the laboratory 'LARHYSS, University of Biskra.Item Fuzzy Sliding Mode Controller For Doubly Fed Induction Motor Speed Control(University of Eloued جامعة الوادي, 2010-07-01) Bekakra, Y.; Ben Attous, D.This paper, presents a Direct Field-Oriented Control (DFOC) of doubly fed induction motor (DFIM) with a fuzzy sliding mode controller (FSMC). Our aim is to make the speed control robust to parameter variations. The variation of motor parameters during operation degrades the performance of the controllers. The use of the nonlinear fuzzy sliding mode method provides very good performance for motor operation and robustness of the control law despite the external/internal perturbations. The chattering effects is eliminated by a particular function "sat" that presents a serious problem to applications of variable structure systems. The fuzzy sliding mode controller is designed in order to improve the control performances and to reduce the chattering phenomenon. In this technique the saturation function is replaced by a fuzzy inference system to smooth the control action. The proposed scheme gives fast dynamic response with no overshoot and zero static error. To show the validity and the effectiveness of the control method, simulation results are performed for the speed control of a doubly fed induction motor. Simulation results showed that improvement made by our approach compared to conventional sliding mode control (SMC) with the presence of variations of the parameters of the motor, in particular the face of variation of moment of inertia and disturbances of load torque. The results show that the FSMC and SMC are robust against internal and external perturbations, but the FSMC is superior to SMC in eliminating chattering phenomena and response time.Item Evaluation Of The Thixotropy Of Oil-well Cements Used For Cementing Lost Circulation Zones: Effect Of Plaster And Blast Furnace Slag(University of Eloued جامعة الوادي, 2010-07-01) Bouziani, T.; Makhloufi, Z.; Benmounah, A.; Bédérina, M.Cementing of oil and gas wells can be a very delicate operation. Among the concerns of service companies, during this operation are the nature and conditions of the formations in well. This is the case of cementing operations in southern Algeria, specifically on the fields of In-Amen, where the formations in lost zones are naturally weak and highly permeable. In these areas, drilling fluids (muds and cements) pumped will be, completely or partially lost, what we call "lost circulation". Thixotropic cements are useful to overcome lost circulation problems. They are characterized by a special rheological behavior, allowing it to plug lost zones when they are pumped. Our work aims to assess the thixotropy of cements perapred with two types of cement (class G Asland cement and CEM I 42.5 portland cement) with the plaster, using a viscometer with coaxial cylinder (couette type). Moreover, the effect of blast furnace slag (LHF) on the properties and thixotropic mixtures prepared was also studied. The results show that portland cement (available locally) can produce mixes with higher and more stable thixotropy than the class G cement (from importation), which is a practical and economical for cementing job operations in wells with loss zones. The results also show that the effect of LHF is positive, since in addition to his contribution to long term performances, especially the durability of hardened concrete, it improves the thixotropy of cement made of plaster.Item Situation Of Fluorides Rate In Waters And Major Consumed Food In Wilaya El-oued(University of Eloued جامعة الوادي, 2010-07-01) Zobeidi, A.; Messiatfa, A.The effects of mineral salts in the drinking water, beneficial or harmful depending on their concentration, are known for many years and thus the problem posed by fluoride ions in the waters of the region (Fluorosis Dental and skeletal). This study proposes, the estimated daily intake of fluoride from its water distribution and the main food consumed per capita in the region of El-Oued (dates, tea, couscous, lentils, carrots, potatoes, pumpkin ...), which has a significant content of fluoride in their composition. In addition to the arid climatic conditions, the air temperature is very high in summer, leads to a strong human perspiration. This preliminary result leads us to propose a standard fluoride-specific region of El-Oued. The results showed that the majority of water samples and analyzed the main foods of the region of El-Oued is charged fluoride ions and exceed the maximum dose recommended for adults from 0.05 to 0.07 mg / kg / day.Item Study Of Intra Testicular Regulations Of Spermatogenesis Differentiation By Ex-vivo Approach(University of Eloued جامعة الوادي, 2010-07-01) Adaika, A.; Barenton, B.; Durand, P.The aim of this work is to study the regulation of intratesticular during spermatogenesis ex vivo. To highlight the progress of spermatogenesis ex vivo, we developed two cell culture systems of seminiferous tubules to study the role of local factors that control the proliferation and differentiation of male germ cells. Our studies are based on two main techniques: RT-PCR and RNA extraction to examine changes in the expression of some growth factors in the culture of seminiferous tubules as the SCF, c- Kit and TGFß. The results show, using RT-PCR, that expression of SCF, c-Kit and TGFb is probably not involved in the alterations of spermatogenesis ex vivo. Indeed, their expressions are not modified during three weeks of culture, and their expressions depend on the proportion of cells where they are expressed. Our results also show that clusterin is a marker of Sertoli cells in the culture of seminiferous tubules and its expression is not altered by the presence of germ cells.