Thermal Conductivity and Mechanical Properties of Organo -Clay-Wood Fiber in Cement-Based Mortar

This paper orientated to study the compressive resistance and thermal conductivity of compressed and stabilized clay blocks in the cement matrix. The effect of the content of wood fiber (WF) became studied as a reinforcement material in cement mortars. The porosity, compressive energy, thermal conductivity and composite of cement hydration had been investigated. The addition of NFC suggests a very good pore reduction, and the fine result becomes acquired with the emulsion of a combination incorporating 2%wt of WF inside the presence of an anionic surfactant (SDBS). The results revealed that used in this study were a mix of water with ordinary portland cement and organo-clay (OC) modified with Cetyltrimethylammonium bromide at water-to-solid ratios 1%. The effect depending on w/s ratio of OC used samples with cement substitution for organoclay showed from 2% higher compressive strength results than that of the plain cement paste and a decrease of the thermal conductivity by addition of 2%wt of WF from 2.26 to 0.8 W/m °C. It was also observed that with increasing w/s ratio higher amount of cement can be replaced by OC. These analyses have revealed that the presence of WF promoted the hydration, by producing more portlandite and calcium silicate gel

Dimensioning of an Autonomous Photovoltaic Installation: Case Study in Msaken, Sousse (Tunisia)

Renewable energy production has the potential to replace traditional fossil energy and reduce the consumption invoice. In this context, a client wants to realize an autonomous photovoltaic installation for his house that is under construction, located in the city of Msaken, Sousse (Tunisia), in an isolated area of the network of the Tunisian Company of Electricity and Gas (STEG) and will be inhabited by the end of the year 2019. The installation autonomy must be 72 hours in case of bad weather. Therefore, in this chapter, we will determine the technical characteristics of each component of the installation to meet the customer’s energy needs and ultimately provide the total price

Axisymmetric High Temperature Jet Behaviours Based on a Lattice Boltzmann Computational Method. Part I: Argon Plasma

Résultats préliminaires. Projet d'article avant soumission à une revueThis article aims to address the issue of simulating plasma-jet by using an innovative computational approach namely the Lattice Boltzmann Method (LBM) from the point of view of extending the applications to simulating flows with temperature-dependent physical parameters. The work focuses on the phenomena occurring in plasma-jet that define the link between LBM lattice and physical lattice. High temperature dependence of the plasma parameters is considered. Argon characteristics fall into this category. This gas is one of the most ones used in plasma spraying. Complex thermal plasma jet phenomena and basis of classical methods in CFD (discretization, stability condition, modeling...), in one side, and the simple scheme of the Boltzmann equation which is particularly adopted for simulating gases flows, in the other side, give us the possibility of taking out the dynamic and thermal characteristics of this complex flow. An important section on validation of this model includes details of available reference results is presented and discussed. It focuses mainly on the validation of our results with previous numerical and experimental results based on the centerline temperature and velocity profiles, its distributions over the computational domain and eventually the effect of the computational domain size. The jet width, the Gaussian radial profiles and the effects of inlet quantities are analyzed. A real spraying configuration is also examined. The quality of the results shows a great efficiency for the lattice Boltzmann method

Etude de la solidification rapide d'une lamelle métallique en contact imparfait avec un substrat céramique

International audienceCe travail s'intéresse au problème de solidification de matériaux bicouche en régime transitoire, dont les propriétés thermophysiques dépendent de la température. Le modèle numérique utilisé est basé sur une approche enthalpique pour résoudre le problème de changement de phase dans chacun des matériaux en présence. Les résultats sont présentés pour plusieurs paramètres tel que l'épaisseur de la lamelle, la résistance thermique de contact, la nature des matériaux et leurs températures à l'impact

LES MÉTHODES DE RÉSOLUTION DE TYPE " LATTICE BOLTZMANN " SONT-ELLES UTILISABLES POUR SIMULER LES JETS PLASMAS SOUFFLÉS ATMOSPHÉRIQUES UTILISÉS EN PROJECTION ?

6 pagesIn this study a new numerical approach of the fluid dynamic, the lattice Boltzmann method (LBM), is used to solved the stream in a atmospheric Argon-nitrogen plasma jet. The axial symmetry and the variation of density, viscosity and conductivity with the temperature are taken into account. The reliability of the results are evaluated from the shareware GENMIX and Jets&poudre

Concentrator Photovoltaic System (CPV): Maximum Power Point Techniques (MPPT) Design and Performance

The research carried out in this work aimed to study the performance of MPPT techniques applied to the Concentrator Photovoltaic (CPV) System for the research and the pursuit of the Maximum Power Point (MPP).This study presents a modeling and simulation of the CPV system. It consists of a PV module located in the focal area of a parabolic concentrator, a DC / DC converter (Boost), two MPPT controls (P&O and FL) and a resistive load. This chapter presents the two MPPT techniques (P&O and FL) performances. The obtained results show the importance of cooling systems integration with CPV system. This hybrid system design results in good MPPT P&O and FL performance. The numerical results obtained with Matlab/Simulink® software have generally shown that the two MPPT controls result in better performance in terms of speed, and accuracy, stability. In fact they showed that the CPV system is stable

Analyse du comportement mécanique de composites bois/plastique en utilisant des mesures en surface par stéréo corrélation d'images numériques

Dans cette étude, les propriétés mécanique et la microstructure d’un composite bois/plastique (WPC) à base de polyéthylène haute densité (PEHD) et de fibres de bois (Pin maritime) ont été caractérisés. Le comportement en traction est globalement élastique non-linéaire endommageable. Le comportement en flexion 4 points du composites a été étudié en utilisant des mesures de champs par stéréo-corrélation d’images numériques. Ces mesures de champs permettent d’observer la répartition spatiale des déformations et d’analyser la capacité de fissuration du matériau. L’endommagement dit de multi-fissurations explique le fait que la déformation moyenne mesurée diverge de la déformation locale (zones de fort gradients). Par cette technique nous avons donc pu déterminer le champ de déformation sur la partie sollicitée en traction ainsi que sur la partie sollicitée en compression lors des essais de flexion 4 points. D’autre part, cette méthode optique nous a permis d’étudier le comportement endommageable et le degré d’hétérogénéité du matériau, que l’on a défini par l’écart type spatial du champ de la déformation longitudinale en traction et en compression sur l’essai de flexion 4 points, et ceci en fonction du pourcentage de bois du composite. Par ailleurs, nous avons pu observer et caractériser, lors d'essai in situ ou à partir des facies de rupture, la morphologie à l’interface fibre de bois/PEHD en utilisant un microscope électronique à balayage (MEB)

Natural convection in shallow cavity filled with nanofluids taking into account the Soret effect

International audienc

Simulation par éléments Finis de l'Ecoulement Viscoélastique dans une contraction 4:1 basée sur le modèle d'Oldroyd-B

Les équations de Navier-Stokes et d'Oldroyd-B régissant l'écoulement viscoélastique dans une  contraction 4:1 sont résolues par une méthode MEF. Des termes de stabilisation sont développés. L'effet de certains paramètres sur l'écoulement a été analysé tels que: la contraction, la quantité de polymère par rapport à celle du solvant, la vitesse d'injection du fluide ou le nombre de Weissemberg. Ces effets sont analysés à travers le  champ de vitesse, les composantes du tenseur extra-contrainte