Liste des documents
Task Performance Evaluation for Supervisory Control Systems
Integrated multi-modal Supervisory Control Systems (ISCS) are a new generation ofcomplex and synergistic Human-Machine Interaction Systems (HMIS). This paper deals withmulti-modal interaction and control applied to Human Robot Systems (HRS). A task performanceevaluation technique dedicated for multi-modal interaction and control is proposed. It enablescomparison of task performance carried out by using different selection of control modes or bydifferent operators. Objective and subjective performance measures are defined.Based on the Analytical Hierarchy Process method (AHP) which takes into account qualitative andquantitative attributes and criteria, a task performance evaluation technique has been proposed forsupervisory systems which enables multimodal interaction modes .Experimental results have been carried out and some preliminary results will be presentedconcerning parallel cable-based manipulators. Voir les détails
Mots clés : Task performance evaluation, human factors, Analytical Hierarchy Process, Adaptive supervisory control, Multi-modal interaction, Cable-based robots, Graphical-user interface.
Élimination du manganèse en solution par le kaolin« Étude cinétique et thermodynamique »
Le kaolin purifié et traité par HCl 0,4 M, a été utilisé comme adsorbant pour éliminer lemanganèse contenu dans les eaux de rejets. La caractérisation physico-chimique a montré quele kaolin de Guelma est constitué en majorité de silice et d’alumine. Sa surface spécifiquemesurée est plus importante pour un kaolin purifié et activé. Le processus envisagé en régimestatique, montre qu’un gramme de kaolin peut fixer selon le modèle de Langmuir premièreversion, jusqu’à 38,23 mg de manganèse avec une cinétique de pseudo 1er ordre. Le temps depseudo équilibre est de 20minutes. Rapport RL montre une bonne affinité du kaolin vis-à-visà l’adsorbat. Le transport externe des ions métallique considérés de la solution versl’adsorbant semble une étape contrôlant la vitesse du processus globale. Cependant, letransport interne dans les pores n’est pas le seul mécanisme limitant de la cinétique desorption. Les paramètres thermodynamique montrent que cette adsorption est spontanées,exothermique et qu’aucun changement n’a été effectue au niveau de sa structure (ΔS<0).L’énergie d’activation est de l’ordre de 27,79 kj/mole Voir les détails
Mots clés : Kaolin, manganèse, adsorption, eau, pollution
Amélioration de la qualité de surface par le procédé de brunissage
La vie d'un matériau en service dépend non seulement de la combinaison des facteurs de charge et d'environnement auxquels il est soumis mais aussi de l'état de surface. Donc la caractérisation de la surface (rugosité, et défauts de surfaces) est importante pour relier le processus de fabrication aux propriétés en service, ainsi le procédé de traitement mécanique "brunissage" peut améliorer les caractéristiques de surface. La qualité du fini de la surface dépend de la maitrise des paramètres de régime de traitement lors de la réalisation. Cette étude a pour objectif, l’application de ce procédé pour un alliage d'aluminium du commerce et l'optimisation du régime de traitement. Les paramètres considérés sont : l'effort appliqué " Py ", l'avance " f " et le diamètre de bille " Db ". La relation entre ces paramètres et la rugosité de surface" Ra " a été mise en évidence à l'aide des plans d’expériences de " Box-Behnken ". Au moyen d'un programme sous Matlab, un régime optimal a été déterminé en vue d'obtenir un maximum d’effet " Ramin". Les résultats expérimentaux ont montré que l'application de ce type de traitement offre des améliorations vis-à-vis de l'aspect de surface pour ce matériau, soit Ra = 0,19 ÷ 0,23 µm. Voir les détails
Mots clés : Mots clés : Brunissage, rugosité, optimisation, plans d'expériences, traitement de surface
New Approach to Modeling a planar flexible continuum robot simulating elephant trunk
Research on the modeling of continuum robots is focused on ways to construct the geometric models, while maintaining maximum specificities and mechanical properties of the robot. This paper presents a new approach of geometric modeling of continuum planar multi- sections robots, assuming that each section is curved in a circular arc, while having inextensible central axis of the structure. The direct geometric model is calculated analytically, whereas the extreme points (used in calculating the inverse geometric model) of each section are calculated numerically using a particle swarm optimization (PSO) method. One advantage of this method is to simplify the mathematical calculations and transform the complex problem into a simple numerical function; which allows the knowledge of the form of the central axis of the robot. Simulation examples using this method are carried to validate the proposed approach. Voir les détails
Mots clés : Flexible Continuum Robot, central axis, PSO, Khalil Klifinger method
Extraction and desextraction of a cationic dye using an emulsified liquid membrane in an aqueous solution
The removal of methylene blue (C16H18ClN3S) as a cationic dye which might be rejected in textile industry wastewaters during its production or its use was the main objective in this work. The extraction was performed by an emulsified liquid membrane (ELM) consisting of sorbitan mono-oleate (SPAN80) and di(2-ethylhexyl)phosphoric acid (D2EHPA) as a surfactant and an extractant respectively. The internal phase used was sulfuric acid. Effects of important factors (concentration of H2SO4, stirring velocity, quantities of organic, aqueous, phases, external and emulsified phases, concentrations of extractant and surfactant were studied according to the stability of the ELM. Then using favorable conditions for a good stability of the membrane, the extraction and of methylene blue (MB) from an aqueous solution was investigated. Optimal conditions were then determined and the extraction efficiency reached 98.15%. The desextraction of this dye was performed at 81.91% and the membrane was regenerated. Voir les détails
Mots clés : emulsified liquid membrane, emulsion W/O, extraction, methylene blue, desextraction
Effects of Niobium and Molybdenum on Microstructures after Hardening and Wear Resistance of Austenitic Manganese Steel
Hadfield steel has been wildly used to manufacture railway crossings because of its excellent work hardening, high strength and toughness properties. The hardness of Hadfield steel is only about 20 HRC when subjected to water toughening. This low hardness is usually associated with poor wear resistance and severe plastic deformation, as well as abrasion of the working surface of the railway crossing during the initial service period, which remarkably reduces its service lifetime. In this study we focus on the influence of niobium and molybdenum on the phenomenon of surface hardening or work hardening and wear resistance. The transformation of austenite during operation, thus determines the steel operating lifetime, the rate of transformation of austenite to martensite can introduce a compromise between ductility and wear resistance of the steel to support large efforts without breaking. The objective of this study is to improve the wear resistance by abrasion and friction after heat treatment of manganese steel alloyed with niobium and molybdenum. The addition of niobium and molybdenum promotes secondary hardening and allows slower transformation of austenite during the heat treatment. The results showed that the introduction of niobium and molybdenum has strongly influenced the character of the structure crystallization before hardening (Part hardened) by precipitation carbides form and finesse variables is observed in the microstructure before heat treatment and complete dissolution is noted after heat treatment, for the hardened part (work hardening) we observed a greater thickness and hardness compared to the base steel and net improvement in wear resistance. Voir les détails
Mots clés : Hadfield steel, Effects of Niobium and Molybdenum, Wear Resistance
Analog Circuit Implementation of FractionalOrder Damped Sine and Cosine Functions
This paper introduces for thefirst time analog circuitimplementations of two fundamental linear fractional order systems whose impulse responses called fractional order damped sineand cosine functions are the inverse Laplace transform of their irrational transfer functions. These analog circuit implementationsare derived through rational function approximations of their irrational transfer functions. Voir les détails
Mots clés : Analog circuit, fractionalorder differential equation, fractional order system, irrational function, rational function.
Effect of Substrates on the Properties of ZnO ThinFilms Grown by Pulsed Laser Deposition
Polycrystalline zinc oxide (ZnO) thin films have been deposited at 450˚C onto glass and silicon substrates by pulsedlaser deposition technique (PLD). The used source was a KrF excimer laser (248 nm, 25 ns, 5 Hz, 2 J/cm2). The effectsof glass and silicon substrates on structural and optical properties of ZnO films have been investigated. X-ray diffraction patterns showed that ZnO films are polycrystalline with a hexagonal wurtzite—type structure with a strong (103)orientation and have a good crystallinity on monocrystalline Si(100) substrate. The thickness and compositional depthprofile were studied by Rutherford Backscattering spectrometry (RBS). The average transmittance of ZnO films deposited on glass substrate in the visible range is 70%. Voir les détails
Mots clés : ZnO, Thin films, PLD, Silicon, X-ray diffraction, Optical transmittance, RBS
Characteristics of Al-doped TiO2 thin films grown bypulsed laser deposition
Al-doped TiO2 (TiO2:Al) thin films were deposited at 450ºC ontoglass substrates using pulsed laser deposition method. X-rays diffractionspectra showed that the obtained films are polycrystalline of anatase structurewith preferential orientation of (101) direction. AFM images, nanoparticles sizeand surface roughness mean square values showed that the surfaces of TiO2:Alfilms are smoother than that of undoped TiO2 films. A blue shift in theabsorption edge of TiO2 with increasing Al concentration in the film isnoteworthy as it leads to increase in the width of the optical transmission. Theoptical waveguiding performances of the TiO2:Al films were demonstrated byusing the m-lines spectroscopy technique and the results were correlated to thestructural properties. Spectroscopic ellipsometry was used to extract the opticalconstants of the films. The determined band gap of undoped and Al doped filmsvaries from 3.43 to 3.61 eV, which is in accordance to Burstein-Moss shift. Voir les détails
Mots clés : Al-doped TiO2, structure, morphology, optical properties, waveguide, nanoparticles
Effects of Niobium and Molybdenum on Microstructures after Hardeningand Wear Resistance of Austenitic Manganese Steel
Hadfield steel has been wildly used to manufacture railway crossings because of its excellent workhardening, high strength and toughness properties. The hardness of Hadfield steel is only about 20 HRC whensubjected to water toughening. This low hardness is usually associated with poor wear resistance and severeplastic deformation, as well as abrasion of the working surface of the railway crossing during the initial serviceperiod, which remarkably reduces its service lifetime. In this study we focus on the influence of niobium andmolybdenum on the phenomenon of surface hardening or work hardening and wear resistance. Thetransformation of austenite during operation, thus determines the steel operating lifetime, the rate oftransformation of austenite to martensite can introduce a compromise between ductility and wear resistance ofthe steel to support large efforts without breaking. The objective of this study is to improve the wear resistanceby abrasion and friction after heat treatment of manganese steel alloyed with niobium and molybdenum. Theaddition of niobium and molybdenum promotes secondary hardening and allows slower transformation ofaustenite during the heat treatment. The results showed that the introduction of niobium and molybdenum hasstrongly influenced the character of the structure crystallization before hardening (Part hardened) byprecipitation carbides form and finesse variables is observed in the microstructure before heat treatment andcomplete dissolution is noted after heat treatment, for the hardened part (work hardening) we observed agreater thickness and hardness compared to the base steel and net improvement in wear resistance. Voir les détails
Mots clés : manganese steel, Effects of Niobium and Molybdenum, Hardeningand, Hardeningand Wear Resistance