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Nombre total de résultats : 288
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Spatially Varying Weighting Function-BasedGlobal and Local Statistical Active Contours.Application to X-Ray Images

Aicha Baya Goumeidane, Nafaa Nacereddine (2016)

Image segmentation is a crucial task in the image processingfield. This paper presents a new region-based active contour whichhandles global information as well as local one, both based on the pixelsintensities. The trade-off between these information is achieved by aspatially varying function computed for each contour node location. Theapplication preliminary results of this method on computed tomographyand X-ray images show outstanding and efficient object extraction.Voir les détails

Mots clés : image segmentation, Active contour, Averaged Shifted Histogram, pressure forces, Spatially varying function

Improvement of surface finish by ball burnishing:approach by fractal dimension

M. BOUREBIA, L. Laouar, H. Hamadache & S. Dominiak (2016)

The surface roughness significantly affects the quality of parts and their functional properties suchas contact surface, as well as coating adhesion. The machined surface quality is evaluated byarithmetic deviation Ra which does not suffice to describe the surface irregularities. In order toapprehend these deficiencies a new technique based on fractal geometry was introduced. Toapply this concept an experimental work was carried out to characterise surface quality byfractal dimension ‘D’. The operations of burnishing ball were performed according to plans ofexperiments of ‘Box–Behnken’, an optimal regime was obtained and a mathematical model wascleared for predicting the fractal dimension ‘D’ as a function of treatment regime parameters.Furthermore, the application of optimal regime under several passes ‘i’ has enabled to examinethe evolution of ‘D’. The results confirm that fractal dimension ‘D’ has impact on surface qualityand tribological parameters.Voir les détails

Mots clés : roughness, fractal dimension, Burnishing process, Designs of experiments

Evaluation of surface quality by Fractal Dimension and VolumeParameters

Mounira Bourebia, Hichem Bounezour, Lakhdar Laouar, Hamid Hamadache (2016)

This study aims, the evaluation of the surface quality by the fractal dimension "D" and volume settings (Vmp,Vmc, Vvv). Experimental work was conducted by process of surface mechanical treatment; in this case ballburnishing was applied on a commercial aluminum alloy material. Three parameters of regime were considered:"burnishing feed f", "burnishing force Py" and "burnishing ball diameter Db". Mathematical models wereidentified using the plans of multifactorial experiments "Box-Behnken" for prediction of fractal dimension "D"and volume parameters. Experimental and simulation results have enabled to show than the large diameter ballunder low loads and medium feed speeds, favors the elimination of peaks and reduction of fractal dimensionwhence quality improvement of surface.Voir les détails

Mots clés : burnishing, volume parameters, fractal dimension, experimental designs

Microstructure and mechanical behavior in dissimilar 13Cr/2205stainless steel welded pipes

K. Bettahar, M. BOUABDALLAH, R. Badji, M. Gaceb, C. KAHLOUN, B. BACROIX (2015)

Thiswork aims to investigate the microstructure and themechanical behavior of dissimilar 13Cr Supermartensitic/2205 Duplex stainless steelwelded pipes. A wide variety ofmicrostructures resulting fromboth solidification andsolid state transformation is induced by the fusion welding process across the weld joint. The tensile tests showthat the deformation process of the dissimilarweld joint ismainly controlled by the two basematerials: the duplexsteel at the beginning of the deformation and the supermartensitic one at its end. This is confirmed by the microtensiletests showing the overmatching effect of the weld metal. The fatigue tests conducted on dissimilar weldedspecimens led us to conclude that the weld metal is considered as a weak link of the weld joint in the high cyclefatigue regime. This is supported by its lower fatigue limit compared to the two basematerials that exhibit a similarfatigue behavior.Voir les détails

Mots clés : Dissimilar welding, microstructure, Tensile testing, High cycle fatigue

Assessment and analysis of wind energy generation and power control ofwind turbine system

Khouloud BEDOUD, Mahieddine Ali-rachedi, Rabah Lakel (2016)

This study concerns the evaluation of wind power potential and the choice of a wind turbine to be installed nearRabah Bitat international airport of Annaba. Furthermore, the performances of power control of this turbine aredeveloped. For this, the wind speed data measured by meteorological station of the airport are used. At the firsttime, a statistical analysis of wind characteristics and the extrapolation of weibull parameters are presented.Otherwise, the analysis of the power produced and the capacity factor led to the choice of the wind turbineEnercon E-82/2000 whose characteristics: Rated wind speed (13m / s), the cut-in wind speed (2.5m / s) and arated power of 2000kW. Finally, the control of the active and reactive power, by adaptive fuzzy gain schedulingof proportional integral controller is simulated using software Matlab/Simulink, studies on a 2 MW DFIG windgeneration system. Performance and robustness results obtained are presented and analyzed.Voir les détails

Mots clés : Wind energy, wind speed, weibull distribution, capacity factor, power output.

Comparative Study of Wind Energy Conversion SystemDriven by Matrix Converter and AC/DC/AC Converter

K. Bedoud, T. BAHI, H. MERABET (2016)

In this work we presents comparative study of avariable speed wind energy conversion system (WECS) basedon the doubly fed induction generator (DFIG) driven by twoAC/DC/AC converters and WECS driven by matrix converter(MC). The whole system is presented in d-q-synchronousreference frame. For this purpose, the control of the activeand reactive power using PI controller is verified usingsoftware Matlab/Simulink, studies on a 1.5 MW DFIG windgeneration system. Simulation results obtained are presentedand analyzed. The results show the high performance andimprove the electric energy of the control strategy adopted inthe WECS based on a DFIG driven by a MC.Voir les détails

Mots clés : wind systems, doubly fed induction generator, matrix converter, simulation

Effect of Grain Size of Nano Composite on Raman and Magnetic Proprieties

A.Younes, N E. BACHA, M.Zergoug, M.Gousmine, H.DEHDOUH, A.BOUAMER (2017)

Based Iron-cobalt alloys exhibit particularly interesting Raman and magnetic properties, with high Curie temperatures, the highest saturation magnetizations, high permeability, and low losses and is relatively strong and partial oxidation of Fe and Co. The cost of these alloys has confined them, since their discovery by Elmen in 1929, to applications where the volume is small and high magnetic performances are critical. Sintering is the procedure of formation and compaction of a material. We have prepared the nano crystalline alloy by the mechanical milling process in a high energy planetary ball-mill PM400. Morphological, micro-structural, magnetic characterizations of the powders milled several times were investigated by scanning electron microscopy, X-ray diffraction, vibrating manometers sample and Raman spectroscopy. The coercivity value increase during millingtime from 0.018 to 185.9 Oe and saturation magnetization value from 42.7 to 51.1 emu/g, respectively.Voir les détails

Mots clés : Mechanical Alloying, Nanostructured FeCo, Magnetic and Raman characterization


Hichem MERABET, Tahar Bahi, DRICI Djalel, Noura Halem, Khouloud BEDOUD (2017)

The three-phase induction machine (IM) has a large importance and it is widely used as electromechanical system device, and because of their; robustness, reliability, and simple design with the well developed technologies. In spite of all cited advantages, the induction machines are suscptible to various types of electrical and mechanical faults that can lead easly to excessive downtimes, which can lead to tuge losses in terms of maintenance and production. This work presents a reliable approach for diagnosis and detection of broken bar faults in induction machine. The detection of faults is based on monitoring of the stator current signal. Also the calculation of relative energy value for each level of signal decomposition is determinated by using package wavelet, and this method will be useful as data input of Adaptive Neuro-Fuzzy Inference System (ANFIS). In the ANFIS approach the adaptive Neuro-Fuzzy inference system is able to identify the rotor of induction machine state with high precision.This method is applied by using the MATLAB®/Simulink software.Voir les détails

Mots clés : Induction machine, Neuro-Fuzzy inference system., Inductoion Machine

On-Line Monitoring and Classification of Stator windings Faults inInduction Machine Using Fuzzy Logic and ANFIS Approach

Merabet. Hichem, Bahi. Tahar, DRICI. Djalel, Bedoud. Khouloud, Boudiaf. Adel (2016)

the induction machines drives becomes moreand more important used in many industrial applications.Their attractiveness is largely due to their simplicity,ruggedness and low cost manufacture, easy maint00enance,high power efficiency and high reliability, are susceptible tovarious types of electrical and/or mechanical faults that canlead to unexpected motor failure and consequently impulsivedowntime. This made necessary the monitoring functioncondition of these machines types for improved anexploitation of the industrial processes. The aim of this taskis the proposal of a monitoring strategy based on the fuzzylogic inference system (FIS) and the neuro-fuzzy inferencesystem (ANFIS) for monitoring and classification ofelectrical faults types, especially the open phase and interturnsshort-circuit in the stator windings. The principleadopted for the strategy suggested is based on monitoring ofthe average root mean square value of stator current (RMS).Mathematical models and simulations results are presentedto validate the efficiency of this approach.Voir les détails

Mots clés : Monitoring, classification, Fis, INFIS, RMS

Monitoring of Stator windings Faults in Induction Machine Using Fuzzy Logic

Merabet hichem, DRICI. Djalel, AOUABDI. Salim (2016)

the monitoring and fault detection of theinduction machines drives becomes more and moreimportant. This made necessary the monitoringfunction condition of these machines for improved anexploitation of the industrial processessing. The aim ofthis task is the proposal of a monitoring strategy basedon the fuzzy logic inference system, that informs usabout the healthy function and stator fault condition,especially the open circuit and short-circuit inter-turnsof the stator windings. The principle adopted for thestrategy suggested is based on monitoring of theaverage root mean square value of stator current(RMS).Theoretical analysis, simulations results arepresentes to validate the effectiveness of the proposesdmethod.Voir les détails

Mots clés : Induction machine, Monitoring, diagnosis, Detection, Fuzzy logic, RMS