Liste des communications
A Comparative Study between the Two Applications ofthe Neural Network and Space Vector PWM for DirectTorque Control of a DSIM Fed by Multi-Level Inverters
Nowadays, thanks to the development of control and power electronics, the dualstator induction machine DSIM has become among the most important multi-phase machinesincluded in the industrial application of welding process, this is due to its positive featuresamong them is its high reliability and reduce both losses and rotor torque ripple.This paper aims to apply both techniques of artificial intelligence represented by the neuralnetwork algorithm NNA and the Space Vector PWM SVM for direct torque control DTC of theDSIM to improve the machine performance to control speed wire of Gas Metal Arc Welding(GMAW), and control algorithms DTNC and DTC-SVM.Generalization capacity, the parallelism of operation, computational speed, and learning ca-pacity all these features made it possible to exploit the neural network algorithm to control themachine. Fixed switching frequency obtained, dispensed with the vector selection table and thehysteresis controller, the three pros allowed the inclusion of SVM technique in DTC strategy.The converters are included to feed the DSIM and the GMAW process. A several of the re-sults obtained prove the two applied techniques (NNA, SVPWM) in improving the quality ofboth electromagnetic torque and flux and the dynamic responses of the DSIM. Voir les détails
Mots clés : GMAW, DSIM, Neural Network Algorithm NNA, Space Vector PWM SVM, DTNC, DTCSVM, Three-level NPC inverter
Optimizing MAG Welding Input Variables to Maximize Penetration Depth Using Particle Swarm Optimization Algorithm
Systems based on artificial intelligence, such as particle swarm optimization and geneticalgorithm have received increased attention in many research areas. One of the main objectives inthe gas metal arc welding (GMAW) process is to achieve maximum depth of penetration (DP) as acharacteristic of quality and stiffness. This article has examined the application of particle swarmoptimization algorithm to obtain a better DP in a GMAW and compare the results obtained with thetechnique of genetic algorithms. The effect of four main welding variables in GMAW process whichare the welding voltage, the welding speed, the wire feed speed and the nozzle-to-plate distanceon the DP have been studied. For the implementation of optimization, a source code has beendeveloped in MATLAB 8.3. The results showed that, in order to obtain the upper penetration depth,it is necessary that: the welding voltage, the welding speed and the nozzle-to-plate distance must beat their lowest levels; the wire feed speed at its highest level Voir les détails
Mots clés : Artificial intelligence, Particle Swarm Optimization, Genetic algorithm, GMAW, penetration depth, optimization, Matlab
High overtone acoustic resonator HBAR based onIDT’s/c-tilted ZnO/Si for timing applications
In this paper, the frequency characteristics ofhigh overtone bulk acoustic modes, generated by interdigitaltransducers IDT’s on c-tilted ZnO/Si, are theoretically andexperimentally investigated. The origin and characteristics ofhigh overtone acoustic modes in ZnO piezoelectric layer onsilicon substrate are discussed and one port HBAR resonator,based on c-axis tilted ZnO/Si, is fabricated and tested bynetwork analyzer. The results achieved in this work are ofinterest in design and fabrication of radiofrequency sourcesand electronic timing devices based on thin film technology Voir les détails
Mots clés : High overtone bulk acoustic modes, HBAR resonator, piezoelectric thin film, c-tilted ZnO, Frequency characteristics
Numerical study of polymer coating by UV photopolymerization.
Polymer-based coatings are used to protect a structure or device against mechanical attacks such as scratches, abrasion and erosion or against chemical attacks such as humidity, temperature, UV rays. This work concerns the development by photopolymerization UV of new coating materials based on a polymer as (Polyurethane Acrylate, oligomers) deposited on heat-sensitive materials such as thermoplastics (PC; PMMA,). Now, the polymers, which are already used in thermal powder coating. They generally show very high melting temperatures (around 200 °C). They will not be suitable for depositing on supports sensitive to high temperatures without risk of damaging them. In this work, we proposed a numerical study of the effect of different synthesis parameters (energy and applied UV rays, exposure time, temperature, external medium, etc.) on the conversion rate to a 3D mesh (crosslinking rate) and model optimization of coating parameters on heat-sensitive substrates. Voir les détails
Mots clés : polymers, coatings polymer, photopolymerization UV
Study of the Bioactivity of Hydroxyapatite Elaborated
This work presents a study on the elaboration and characterization of Hydroxyapatite obtained from bovine bone calcined at 900°C for 3 hours with a particle size of around 125 μm and sintered at 1100°C. A prepared biological solution (Simulated Body Fluid, SBF), to study the biological response of our elaborated powder.We carried out a characterization by scanning electron microscopy (SEM) in order to observe the formation of the apatite layer during the immersion time. Voir les détails
Mots clés : hydroxyapatite, SBF, Biological response, Osteoconductivity
Materials sciences And Engineering, (MSE’22)
This work presents a study on the elaboration and characterization of Hydroxyapatite obtained from bovine bone calcined at 900°C for 3 hours with a particle size of around 125 μm and sintered at 1100°C. A prepared biological solution (Simulated Body Fluid, SBF), to study the biological response of our elaborated powder.We carried out a characterization by scanning electron microscopy (SEM) in order to observe the formation of the apatite layer during the immersion time. Voir les détails
Mots clés : hydroxyapatite, SBF, Biological response, Osteoconductivity
Effect of fatigue on Mechanical Behaviors of Weld Overlay ENiCrMo-3 on 25CD4 Steel Substrate Using SMAW Process
In the present study, we investigated the effect of fatigue on the mechanical behaviors of weld overlay ENiCrMo-3 on a 25CD4 steel substrate using the SMAW process. The microstructure of the ENiCrMo-3/25CD4 substrate interface primarily consisted of columnar Ni-γ. a diffusion gradient of Fe, Cr, and Ni elements from the melting limits towards the type II boundary near the interface. Based on the fatigue test results, the specimen, which was tested at the ultimate tensile strength, exhibited superior fatigue endurance compared to the first specimen tested at the ultimate tensile strength. elasticity limit. This suggests that the material had greater fatigue resistance when subjected to a percentage of the ultimate tensile strength, as it withstood a greater number of cycles over a longer duration. The electrochemical behavior of the ENiCrMo-3 overlay and the 25CD4 substrate in a NaCl 3.5% solution indicated the presence of galvanic corrosion. The Tafel curves demonstrated that the corrosion process could be divided into two parts, emphasizing the aggressiveness of Cl- ions. Electrochemical impedance spectroscopy (EIS) measurements showed that the resistance to charge transfer of the ENiCrMo-3 hardfacing was greater than that of the substrate/ENiCrMo-3 interface and the substrate itself Voir les détails
Mots clés : 25CD4 steel substrate, ENiCrMo-3 hardfacing, fatigue behavior
Experimental and theoretical studies on the anticorrosion performance of co-polymeric coatings on X70 steel in 3.5% NaCl
Polymeric coatings are used to protect metallic surfaces from corrosion in a marine environment. The novelty of this research lies in the combination of two conductive polymers, namely Polypyrrole (PPy) and Ortho-toluidine (OT), which were tested for their corrosion resistance on steel in a chloride medium. The polymers were synthesized electrochemically using the galvanostatic mode. The corrosion properties were studied using electrochemical methods such as the evolution of open-circuit potential over time and polarization curves. The purpose of this research is to enhance the protective capabilities of polymeric coatings by combining these two polymers. Initially, layers of PPy and OT were deposited on X70 carbon steel. The focus was on optimizing single layers of PPy alone before enhancing the coatings with PPy/OT bilayers. The results indicate that the application of PPy and OT copolymerization could significantly improve the corrosion resistance of tool steel structures. To understand the mechanism involved in electrodeposition, it was deemed useful to use quantum calculations based primarily on the density functional theory (DFT). This study highlights the relationship between the structural arrangement, electronic structure, and inhibitory activity of different compounds through a number of quantum descriptors such as the highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energy, the ΔE gap, and the dipole moment μ of the surface coating. The results of the DFT calculations obtained are in fairly good agreement with experimental data. Voir les détails
Mots clés : Copolymer coating, corrosion resistance, X70 steel, DFT
Bio-molecule as a sustainable protection against corrosion of ductile iron in acid solution: Experimental and computational studies
The present work is devoted to study the inhibition effect and adsorption mechanism of Loratadine (LRD) on cast iron in 1 M HCl. Polarization curve, electrochemical impedance spectroscopy (EIS) and surface analysis were carefully investigated to indicate the inhibition effect of LRD on cast iron in 1 M HCl. On the other hand, Theoretical study evidenced the good loratadine reactivity toward cast iron surface. Polarization curves revealed that LRD behaves as mixed type inhibitor. The inhibition efficiency increased with the increasing concentration of LRD and reached 91 % (by EIS) at 0.46 mM of inhibitor. It showed that the adsorption of LRD on cast iron surface followed the Langmuir isotherm. The value of ΔG°ads (-37.52 kJ/mol) and the effectiveness of LRD at high temperatures, suggest physicochemical interactions of LRD with the cast iron surface. A good correlation was made between some electronic properties of LRD molecules and adsorption mode. The obtained results showed that Loratadine is an efficient corrosion inhibitor for cast iron in 1 M HCl. Voir les détails
Mots clés : corrosion inhibitor, EIS, Quantum calculations, Biomolecule
Enhanced Understanding of Corrosion Performance in Lean Duplex Stainless Steel Exposed to Aging Treatment and Mechanical Stress
This paper investigates the influence of heat treatment and mechanical stress on the microstructure, magnetic characteristics, and corrosion resistance of 2101 lean Duplex Stainless Steel (DSS). Specifically, at a temperature of 750°C during the aging treatment, the emergence of the sigma phase, in conjunction with mechanical stress, leads to material embrittlement. The study explores the applicability of employing Vibration Sample Magnetometer (VSM) and eddy current testing to detect microstructural modifications and evaluate corrosion behavior. Corrosion effects are analyzed using potentiodynamic methods (PM). Notably, a robust correlation is established between the proportion of sigma phases and electrochemical parameters. The samples are subjected to a range of conditions, including untreated states, exposure to elevated temperatures, corrosive environments, and axial loading. Material responses are meticulously examined utilizing eddy current techniques. This investigation compellingly demonstrates the capacity to identify and quantify all microstructural alterations in the samples through magnetic measurements. Voir les détails
Mots clés : LDX 2101, corrosion, aging treatment, microstructure, Mechanics stress, VSM, Hysteresis Loop, Eddy Current