Cet article rapporte une étude numérique et analytique de la convection naturelle au sein d’une cavité horizontale remplie par un fluide non newtonien. Les parois horizontales sont soumises à un flux de chaleur uniforme et celles verticales sont adiabatiques. Trois conditions hydrodynamiques sur les frontières horizontales (rigide-rigide (RR), libre-libre (FF) et rigide-libre (RF)) sont considérées. Un modèle rhéologique de type loi de puissance est utilisé pour modéliser le comportement non newtonien du fluide. Pour mener à bien cette étude un code de calcul numérique, basé sur la méthode des différences finies, a été adopté et un modèle analytique de type écoulement parallèle valable pour les couches minces ( A>>1) a été développé.

This paper presents the impact of three series Flexible AC Transmission System (FACTS) devices, namely the Thyristor Controlled Series Capacitor (TCSC), GTO Controlled Series Capacitor (GCSC) and Thyristor Controlled Series Reactor (TCSR), on the short circuit calculations of a 400 kV electrical transmission line in case of a phase to earth fault in the presence of a fault resistance (RF). The case study is a 400 kV single transmission line in the northern Algerian transmission network which is compensated by each of the three mentioned FACTS devices, consequently. Each compensator is connected at the midpoint of the line to control the reactive power and reactance of the line. The obtained simulations results investigate the impact of the fault resistance, which varies between 0 to 50 Ω, on the parameters of short circuit calculations, without compensation and with each FACTS device. The obtained simulation results match the presented theoretical analysis.

Reservoir sedimentation affects the performance of dams in Algeria from the standpoint of reservoir capacity for storage. Foum El Kherza reservoir near Biskra Town, Algeria, is subject to dredging operation with the intent of recovering 70% of its initial storage capacity of 47 hm3 (million cubic meters). The forecasting of sediment volume trapped in the reservoir is essential to plan the future use of this resource and to sustain irrigation for the palm groves characteristic of the region. However, there are currently no sediment data for predicting sediment inflow based on hydrologic data. Based on earlier study on cumulative sediment rating curve approach using daily inflows, this paper describes an optimization of a cumulative trapped sediment curve for the reservoir based on 44 years of annual water inflows, by using a spreadsheet optimization tool, Microsoft Excel® Solver to calibrate the cumulative sediment load against the cumulative sediment inflow as documented by eight bathymetric surveys since dam construction.

This paper presents the impact study of GTO Controlled Series Capacitor (GCSC) Parameters on MHO distance relays measured impedance for 220 kV protected electrical transmission line in the presence of phase to earth fault. The study deals with a 220 kV single electrical transmission line of Eastern Algerian transmission networks at Group Sonelgaz (Algerian Company of Electrical and Gas), compensated by series Flexible AC Transmission System (FACTS) i.e. GCSC connected at midpoint of the line. The transmitted active and reactive powers are controlled by three GCSC’s. The effects of maximum reactive power injected as well as injected maximum voltage by GCSC on distance relays measured impedance is treated. The simulations results investigate the effects of GCSC injected parameters on measured resistance and reactance in the presence of earth fault with resistance fault for three cases study.

fleet safety is seen as important, not just for fleet operators, but as a strategic approach to improving the safety of the entire vehicle fleet. Corporate purchasers of vehicles and transport services can specify high safety standards and thus create an economic imperative for providers of vehicles and transport services to meet these standards. Fleet management comprises all actions needed to maintain and operate pieces of equipment throughout its life from the beginning stages of equipment acquisition to the final stages of asset disposal. Such areas include maintenance and repair, inventory control, training, and safety issues. A company fleet management process is evaluated using two methods: Haddon matrix which is implemented to evaluate organizational safety context into which the driver assessment, monitoring and improvement program should fit. Haddon provides an all-encompassing pre-crash, atscene and post-crash systems-based framework for fleet safety. The network influence method which is presented as a risk management method.

This paper discusses the control a new topology of a brushless doubly-fed induction generator (BDFIG) using back-to-back PWM converters and its application to variable speed wind energy generation. The goal of BDFIG control is to achieve a similar dynamic performance to the doubly fed induction generator (DFIG), exploiting the well-known induction motor vector control philosophy. Here fuzzy logic controller for a BDFIG. Simulation results have been presented to investigate proposed technique