Key words: Tunnel fire, CO concentration, aspect ratio, CFD.

Abstract: In a tunnel fire, the production of smoke and toxic gases remains the principal factors prejudicial to users. More than 80 % of deaths are in direct relation to the toxicity and the opacity of smoke. In this paper, the smoke propagation and CO production in a longitudinally ventilated tunnel fires for different aspect ratio is analyzed numerically with large eddy simulation (LES) by Fire dynamic simulator (FDS). The evolution of the CO concentration longitudinally along the tunnel will be studied in this work. The tunnel slope’s effect on the CO concentration will also be studied. The FDS Numerical results are firstly verified by comparison with the experimental measurements of Li et al. [15-16], in terms of the critical velocity and the maximum smoke temperature under the ceiling. A relatively good agreement has been obtained. Results show that the CO concentration increases with the aspect ratio while this latter remains lower than 1 and then decreases as the aspect ratio increases for an aspect ratio greater than 1.

Key words: Aerosols, Optical Thickness, MODIS, turbidity parameters.

Abstract: In this work, three basic parameters for aerosol characterization, Aerosol Optical Thickness, Angstrom Exponent and Angstrom Coefficient are used for aerosol analysis. Their monthly average values are obtained from MODIS data for Ghardaia site. We have found that the transmission of solar radiation can reach 95 % and the 94% of the Angstrom exponent values lie between 1.2 and 1.27 and 70% of Angstrom coefficient lie between 0.019 and 0.062.

Key words: Artificial neural network, cutting force components, hard turning, machining process.

Abstract: In this study, we develop a robust ANN technique to predict cutting force components during hard turning of an AISI 52100 steel using CBN cutting tool. The training network is performed on 20 pairs of input-output experimental dataset where cutting parameters and workpiece hardness are taken as the input dataset. Back-propagation training is performed by using Bayesian Regularization in combination with Levenberg-Marquardt algorithm. The optimal network architecture is determined after several simulations by MATLAB Neural Networks Toolbox and it is consisting of 8 neurons in hidden layer. The developed model was verified with other experimental test data not used in training; for this purpose, the maximum average MAPE value of 11.79 % was obtained for the cutting forces prediction.

Key words: Photovoltaic, Partial Shading, Maximum Power Point Tracking, Configuration

Abstract: Partial shading of photovoltaic (PV) modules can affect a wide variety of plants ranging from utility-sized solar trackers to residential building-integrated PV, resulting in lower energy production yields. This paper presents background and experimental results from a PV system, operated under a variety of shading conditions. A procedure of simulation and modeling solar cells and PV modules, working partially shadowed in symbols environment, is presented. Simulation results have been contrasted with real measured data from a commercial PV module of Photowatt PW1650. Some cases of study are presented as application examples of this simulation methodology, showing its potential on the design of bypass diodes configuration to include in a PV module and also on the study of PV generators working in partial shading conditions.

Key words: Variable Speed Hydrodynamics; Bond Graph; Modeling; Fault Detection and Isolation; Simulation

Abstract: Hydrodynamic couplers are often assigned to a group of their own research in the classification of couplings. This is justified by the particular operating principle of hydrodynamic power transmission. The transformation between the form of mechanical energy and hydropower offers various possibilities to vary the transmission power according to precise laws. The main idea to understand and study the dynamics of real systems is the modeling. The models are simplified and abstract constructs used to predict the real behavior. We proposed to use not the bond graph approach like the single tool responsible for modeling, as that is classically proposed in the literature, but like a mechanism complementary to enrichment. With this work, we helped to develop a platform for modeling of a hydrodynamic variable speed transmission able to model its bodies and to simulate and analyze its total behavior thereafter. This paper describes the application of our qualitative fault detection and isolation FDI approach to a hydrodynamics variable speed. We developa pseudo bond graph model of the system and demonstrate the FDI effectiveness. We introduce the problem analysis involved in the faults localization in this process. A number of new and interesting issues have been dealt with in this paper.