Institutional repository of university M'Hamed Bougara Boumerdes
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Modélisation et optimisation de l’intégrité de surface et de l’influence de galetage sur la fatigue des pièces mécaniques
No full text65 p. : ill. ; 30 cmDans ce travail, une étude de l’application du procédé de traitement mécanique par galetage, dans le but d’améliorer et modifie les propriétés de base des couches superficielles des matériaux a été entrepris. Afin de maîtriser ces altérations d’intégrité de surface nous allons nous concentrer dans notre étude sur la prédiction et l’optimisation de la rugosité et de l’écrouissage induits par ce type traitement (galetage) dans des pièces d’acier S355 J0. L'objectif donc est de prévoir l'influence d'une opération de traitement mécanique par galetage sur les paramètres d’intégrité de surface. Les résultats de modélisation et d’optimisation ont révélé que l'avance, la force de galetage et la vitesse de rotation sont les paramètres les plus significatifs influençant la rugosité de surface. De plus, le nombre de passes s’ajoute aux autres paramètres de galetage et influence de manière significative la dureté
Multi variable stabilization control of a hydraulic system
No full text72 p. : ill. ; 30 cmThis Thesis explores the application of the Takagi-Sugeno (TS) fuzzy modeling approach for accurately representing nonlinear hydraulic systems. The TS fuzzy model employs a multi-model fuzzy architecture composed of multiple linear sub-models that locally capture the system dynamics, combined through fuzzy rules to represent the overall nonlinear behavior
Pre-stack Seismic Inversion for Potential Reservoirs’ Characterization in Oued Mya Basin, Algeria
No full textThe main objective of this study is to characterize the potential reservoirs situated in Oued Mya basin in Algeria by using pre-stack seismic inversion data. In fact, rock physics has been used to estimate shear waves and their densities from the compressional wave velocities at six wells, and then, cross-plots were exploited to establish a mathematical relation between the petrophysical and acoustic parameters of the rocks. After that, the lithological classification has been iteratively generalized for the whole seismic volume. The final model, obtained with a correlation ratio of 75%, allowed the classification of the dominant facies in the reservoir. Furthermore, the Petrophysical volumes obtained using these mathematical relations provided the horizontal distribution of the different existing reservoirs with a focus on the potential ones. The obtained results in this case study have highlighted the crucial role played by the seismic inversion in the characterization of the oil reservoirs in the Oued Mya Basin. It also permitted to provide lateral variations of petrophysical parameters of the reservoir; thus, it eliminates the problem of punctuality of the information provided by logging data. This characterization step is very important for determining the positions of new exploration drillings in order to optimize exploration strategy with minimal uncertainties; therefore, exploration costs can be optimized. The main novelty of this paper is that the obtained model was very reliable and its correlations with six wells in the basin were high; hence, it has been used to characterize the reservoirs and to identify new areas with hydrocarbons potentials where highly probable discoveries were identified
Application de la méthode «AMDEC» sur le variateur de vitesse «VSD-ACS1000 d’ABB» de Sonatrach, zone industrielle «Reggane»
No full text73 p. : ill. ; 30 cmLe Variateur de vitesse est un composant crucial dans de nombreux systèmes industriels, permettant de contrôler la vitesse de rotation des moteurs électriques. Sa défaillance peut entraîner des arrêts de production coûteux et des perturbations opérationnelles importantes. Dans cette optique, nous avons entrepris l'optimisation de la maintenance d'un variateur de vitesse utilisé par Sonatrach dans la zone industrielle de Reggane. En recourant à la méthode AMDEC (Analyse des Modes de Défaillance, de leurs Effets et de leur Criticité), nous visons à classer les causes de défaillance selon leurs effets et à déduire les actions correctives appropriées
Promising Algerian essential oils as natural acaricides against the honey bee mite Varroa destructor (Acari: Varroidae)
No full textVarroosis induced by Varroa destructor Anderson and Trueman represents the most pathogenic and destructive disease affecting the western honey bee, Apis mellifera. In this study, we investigated the acaricidal activity against the Varroa mite using essential oils (EOs) from the aerial parts of four autochthonous Algerian herbal species, namely Artemisia herba alba, Artemisia campestris, Artemisia judaica and Ruta montana. EOs were obtained by means of hydrodistillation and their composition was characterized by gas chromatography–mass spectrometry. The toxicity of the selected EOs toward V. destructor and A. mellifera adult honey bees was evaluated using the complete exposure method. The results indicate the predominance of davanone (66.9%) in A. herba alba, β-pinene (19.5%) in A. campestris, piperitone (68.7%) in A. judaica and 2-undecanone (70.1%) in R. montana EOs. Interestingly, the LC50 values coupled to bee mortality rates revealed that all tested oils exhibited significant acaricidal efficiency with selectivity ratio (SR) values of 10.77, 8.78, 5.62 and 3.73 for A. campestris, A. judaica, A. herba alba, and R. montana, respectively. These values were better than that of thymol (SR = 3.65), the positive control. These findings suggest that these EOs could be used as plant-derived veterinary acaricides to control varroosis in field conditions
Systematic evaluation and analysis of failures using «AI»
No full text95 p. : ill. ; 30 cmThis Document outlines the conceptual framework for a pioneering web-based platform designed to blend HSE analyses with AI capabilities. The platform aims to streamline the risk assessment process, making it more accessible and user-friendly while leveraging the power of machine learning, data analytics, and predictive modeling to offer insights that are both comprehensive and forward- looking. By integrating AI into HSE analyses, the platform seeks to not only improve the identification and mitigation of potential hazards but also to predict and prevent future risks, thereby ensuring a safer and more sustainable operational environment
A Novel Design of a Microstrip Antenna Array for Wireless Power Transfer Applications
No full textIn this article, a new 1 × 4 microstrip antenna array operating at 2.45 GHz for wireless power transfer (WPT) applications is proposed. Besides the array configuration, and for maximum power transfer to the load, the performed design puts into contribution three other design techniques which are: defected ground structure, electromagnetic band gap and multilayer topology. The suggested antenna, printed on an FR-4 dielectric substrate, achieves significantly improved directivity and gain of 13.30 dBi and 10.90 dBi, respectively. Furthermore, an input reflection coefficient around − 38 dB, a frequency bandwidth of about 180 MHz and a side lobe level (SLL) below − 20 dB are obtained. It is also observed that the antenna gain is close to its maximum performance across the entire operating frequency band (2.36–2.54 GHz). A prototype of the performed design is fabricated and tested. Experimental results show a good agreement between simulated and measured input reflection coefficients. The achieved performances make the developed structure highly suitable for WPT systems
Computational study of transition metal coordinated polyaniline: A first principle investigation into tuning the electronic properties of the resulting hybrid material
No full textTuning the electronic properties of polyaniline remains one of the most important features for the development of advanced materials in electronics. In this contribution, we use density functional theory to investigate the electronic properties of polyaniline when coordinating transition metals (Mn, Fe, Co, Cu, Zn) are embedded in the polymer structure.
Importantly, the results reveal that in the presence of transition metal with high electronegativity, the coordinated polyaniline winds up with a decreased gap. Indeed, the band gap for H-PANI decreases from 0.911 eV to 0.513 eV for H-PANI-Mn (lower electronegativity) and to 0.201 eV for H-PANI-Zn (higher electronegativity). This reduction in the energy gap is attributed to enhanced electron delocalization due to increased overlap of electron wavefunctions in the hybrid structure. The results also reveal that the presence of transition metals lead to lower the chemical hardness from 3.252 eV in the case of H-PANI into 0.256 eV for H-PANI-Mn and 0.100 eV for H-PANI-Zn. Additionally, the results from molecular electrostatic potential highlight that PANI-Transition metal sustains more delocalization of charge density distribution compared to H-PANI, leading to molecule polarization which does play a crucial role in various chemical phenomena. These later reveal that the electron density polarization in polyaniline can interestingly be controlled through doping and coordinating the polymer structure with additional transition metals. Therefore, the obtained results might be used in the optimization of electrochemical charge storage in supercapacitors
Big data clustering based on spark chaotic improved particle swarm optimization
No full textIn recent years, the surge in continuously accelerating data generation has given rise to the prominence of big data technology. The MapReduce architecture, situated at the core of this technology, provides a robust parallel environment. Spark, a leading framework in the big data landscape, extends the capabilities of the traditional MapReduce model. Coping with big data, especially in the realm of clustering, requires more efficient techniques. Meta-heuristic-based clustering, known for offering global solutions within reasonable time frames, emerges as a promising approach. This paper introduces a parallel-distributed clustering algorithm for big data within the Spark Framework, named Spark, chaotic improved PSO (S-CIPSO). Centered on particle swarm optimization (PSO), the proposed algorithm is enhanced with a chaotic map and an efficient procedure. Test results, conducted on both real and artificial datasets, establish the superior performance and quality of clustering results achieved by the proposed approach. Additionally, the scalability and robustness of S-CIPSO are validated, demonstrating its effectiveness in handling large-scale datasets
Synthèse biomimétique de micro et nano échafaudages-sphères d'apatite/chitosane phosphorylé comme vecteurs de molécules actives à usage dentaire et orthopédique
No full text235 p. : ill. ; 30 cmLa recherche des substituts dentaire et osseux est un axe en plein essor. Vu le potentiel que représente le chitosan (CS), le choix de ce polymère naturel est effectué, dans ce travail en tant que substrat pour le processus de la biominéralisation in vitro. En effet, dans l'optique de former des nanohydroxyapatite (HAP) par la voie biomimétique ce travail propose la préparation des biomatériaux (sous forme de films et de microparticules) à base du chitosane modifié chimiquement par phosphorylation (CSP) et biocomposites (CS/HAP) recouverts d'un phosphate de calcium. Pour consolider la démarche de préparation, une étude des matériaux obtenus par microscopie électronique à balayage (MEB), spectroscopie à rayons X à dispersion d'énergie (EDX), spectroscopie infrarouge à transformée de Fourier (FTIR), diffractométrie des rayons X (DRX) et spectroscopie photoélectronique aux rayons X (XPS) a été effectuée. Il a été montré que la déposition des phosphates de calcium est favorisée par la présence des groupements phosphates dans la formulation initiale que ce soit par phosphorylation (CSP) ou par incorporation de l'hydroxyapatite dans la formulation des biocomposites (CS/HAP). Le revêtement de phosphate de calcium obtenu en mode biomimétique déposé sur les dérivés phosphorylés de CS a été obtenu par un procédé basé sur la phosphorylation, le traitement par Ca(OH)2 et l'immersion dans une solution de salive synthétique (ASS) et une solution de fluide corporel (SBF) à 37 °C pour simuler les conditions physiologiques dentaires et orthopédiques respectivement. En effet, le minéral formé est l'hydroxyapatite carbonatée déficiente en calcium avec des rapports Ca/P allant de 1.5 à 1.67. Les vues MEB obtenues corroborent l'idée de la croissance des cristaux d'HAP au cours de la biominéralisation in vitro. Par ailleurs, pour la préparation des systèmes pharmacologiquement actifs, une étude de la possibilité d'incorporer des substances actives modèles (l'oxytétracycline (OTC), et la gentamicine sulfate (Gs)) à usage dentaire et orthopédique dans les biomatériaux élaborés a été menée. De plus, une étude de la libération contrôlée in vitro de ces antibiotiques a été réalisée dans les conditions physiologiques simulées, avec des taux de libération allant jusqu'à 92.45 % pour l'OTC et 98.21 % pour la Gs. Enfin, une évaluation in vitro de l'activité antimicrobienne des biomatériaux développés a été effectuée contre plusieurs espèces bactériennes et fongiques impliquées dans les infections osseuses et dentaires, notamment Staphylococcus aureus, Staphylococcus epidermidis et Candida albicans. Les résultats ont montré une activité antimicrobienne optimale contre Staphylococcus aureus, avec des zones d'inhibition atteignant 20 m