Polytechnic School of Algiers

Algiers, Algeria

The National Polytechnic School or École Nationale Polytechnique is an elite engineering school founded in 1925. The architectural diversity of the buildings reflects the different extensions and enlargements of the areas of expertise, teachings and research.A common misconception is to call the school the National Polytechnic School of Algiers while its official name is the National Polytechnic School abbreviated in French as ENP. Wikipedia.

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Abdi A.,Polytechnic School of Algiers | Trari M.,University of Science and Technology Houari Boumediene
Electrochimica Acta | Year: 2013

The hematite α-Fe2O3 is prepared by sol-gel route at 900 C. Structural and morphological characterizations are investigated by X-ray diffraction and scanning electron microscopy. The SEM image shows a monophasic structure with a chemical composition uniformly distributed, based on sintered agglomerates particles with no particular orientation. The EDS characterization shows wide non-stochiometry (O/Fe = 0.72). The X-ray diffraction indicates an orthorhombic crystalline structure with an average crystallite size of 87 nm and a surface specific area of 13.3 m2 g-1. The hematite exhibits n-type conduction with direct (1.99 eV) and indirect (1.75 eV) optical transitions. The electrochemical properties are investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant charge-discharge methods in Na2SO3 (1 M) and NaOH (1 M) electrolytes. The CV characteristics show a typical pseudo-capacitive electrode behavior, associated with a faradic mechanism. The electrochemical impedance spectroscopy carried out over the frequency range (1 mHz-100 kHz) exhibits a dominant pseudo-capacitive behavior at low frequencies. The pseudo-capacitive phenomenon is preceded by diffusion process, implying a blocking behavior at high frequencies. The super capacitive properties of Fe2O3 at a scan rate of 5 mV s-1 show a maximum super capacitance of 4.915 and 48.21 F g-1 in NaOH and Na 2SO3, respectively. A typical charge-discharge behavior at 5 mA over a potential window of 1.2 V is obtained with coulombic efficiency approaching 100% in both electrolytes. © 2013 Elsevier Ltd.

Larbi S.,Polytechnic School of Algiers | Chergui T.,Applied Research Unit on Renewable Energies URAER
Renewable and Sustainable Energy Reviews | Year: 2010

In this paper, we present the performance analysis of a solar chimney power plant expected to provide the remote villages located in Algerian southwestern region with electric power. Solar energy and the psychometric state of the air in the south of Algeria are important to encourage the full development of solar chimney power plant for the thermal and electrical production of energy for various uses. We are interested in Adrar where solar radiation is better than other areas of Algeria. The obtained results show that the solar chimney power plant can produce from 140 to 200 kW of electricity on a site like Adrar during the year, according to an estimate made on the monthly average of sunning. This production is sufficient for the needs of the isolated areas. © 2009 Elsevier Ltd. All rights reserved.

Kaabeche A.,Renewable Energy Development Center Algeria | Belhamel M.,Renewable Energy Development Center Algeria | Ibtiouen R.,Polytechnic School of Algiers
Energy | Year: 2011

To allow a real penetration of the huge dispersed naturally renewable resources (wind, sun, etc.) intermittent and more or less easily predictable, optimal sizing of hybrid renewable power generation systems prove to be essential. This paper recommends an optimal sizing model based on iterative technique, to optimize the capacity sizes of different components of hybrid photovoltaic/wind power generation system using a battery bank. The recommended model takes into account the submodels of the hybrid system, the Deficiency of Power Supply Probability (DPSP) and the Levelised Unit Electricity Cost (LUEC). The flow chart of the hybrid optimal sizing model is also illustrated. With this incorporated model, the sizing optimization of grid-independent hybrid PV/wind power generation system can be accomplished technically and economically according to the system reliability requirements. A case study is conducted to analyze one hybrid project, which is designed to supply residential household located in the area of the CDER (Center for Renewable Energy Development) situated in Bouzaréah, Algeria (36° 48′N, 3° 1′E, 345 m). © 2010 Elsevier Ltd.

Kaabeche A.,Renewable Energy Development Center Algeria | Ibtiouen R.,Polytechnic School of Algiers
Solar Energy | Year: 2014

This paper focuses on development of optimal sizing model based on an iterative approach to optimize the capacity sizes of various stand-alone PV/wind/diesel/battery hybrid system components for zero load energy deficit. The suggested model takes into consideration the hybrid system submodels, the Total Energy Deficit (TED), the Total Net Present Cost (TNPC) and the Energy Cost (EC). The flow diagram of the hybrid optimal sizing model is also demonstrated. Exploiting the developed model, all configurations giving the rate of 0% of Total Energy Deficit (TED) are retained. Afterward, the optimal configuration is predicted on the basis of the minimum cost. Using solar radiation, ambient temperature and wind velocity data collected on the site of Ghardaïa (Algeria), the optimized system is compared to other energy source choices. The optimization results show that a PV/wind/diesel/battery option is more economically viable compared to PV/wind/battery system or diesel generator (DG) only. © 2014 Elsevier Ltd.

Touafek K.,Unit of Applied Research in Renewable Energy | Haddadi M.,Polytechnic School of Algiers | Malek A.,Renewable Energy Development Center Algeria
Energy and Buildings | Year: 2013

Hybrid photovoltaic thermal (or simply PV/T) collectors are devices that simultaneously convert solar energy into electricity and heat. The improving of the electrical efficiency, by reducing the photovoltaic collector's temperature, as well as taking advantage of the thermal energy produced, constitutes the basic idea in the development of hybrid PV/T collectors. A new design of hybrid collectors for air heating is presented in this paper. The theoretical study is carried out through the numerical modeling, and the results of the simulation are integrally developed; witch a prototype is realized. Experimental validation of the mathematical model as well as the study of the thermal and electric performance is detailed. The application of this new design has given a good thermal and electric performance compared to the traditional hybrid collectors. Its simplicity of implementation and its easy integration in buildings make them more competitive. © 2012 Elsevier B.V.

Evin G.,University of Newcastle | Favre A.-C.,Polytechnic School of Algiers
Stochastic Environmental Research and Risk Assessment | Year: 2013

Stochastic point processes for rainfall are known to be able to preserve the temporal variability of rainfall on several levels of aggregation (e. g. hourly, daily), especially when the cluster approach is used. One major assumption in most of the applications todate is the stationarity of the rainfall properties in time, which must be reconsidered under a climate change hypothesis. Here, we propose new theoretical developments of a Poisson-based model with cluster, namely the Neyman-Scott Rectangular Pulses Model, which treats storm frequency as a nonstationary function. In this paper, storm frequency is modelled as a linear function of time in order to reproduce an increase (or decrease) of the mean annual precipitation. The basic theory is reconsidered and the moments are derived up to the third order. Then, a calibration method based on the generalized method of moments is proposed and discussed. An application to a rainfall time series from Uccle illustrates how this model can reproduce a trend for the average rainfall. This work opens new avenues for future developments on transient stochastic rainfall models and highlights the major challenges linked to this approach. © 2012 Springer-Verlag.

Merahi F.,Ferhat Abbas University Setif | Berkouk E.M.,Polytechnic School of Algiers
Renewable Energy | Year: 2013

The use of multilevel converters has increased significantly owing to their advantages in high-voltage and high-power applications. Balancing of the DC capacitor in the neutral-point clamped (NPC) topology is a main concern in these converters. The DC voltage must be maintained at its reference value to avoid overvoltage stress on the semiconductor and to overcome modulation distortion. This paper presents a new method of regulating the DC voltage of a back-to-back NPC five-level converter applied in a wind energy conversion system based on doubly fed induction generator. The proposed control algorithms consist of two loops: the outer closed loop controls the average value of the DC voltage, whereas the inner loop controls the difference between the two voltages in each half-arm using a clamping bridge circuit. To verify the validity of the method and to prove the performance of the proposed control algorithms, simulation was carried out in a MATLAB Simulink environment. The results obtained show the effectiveness of the proposed algorithms. © 2013 Elsevier Ltd.

Mendez-Samperio P.,Polytechnic School of Algiers
Infection and Drug Resistance | Year: 2014

Antibiotic resistance is an increasing public health concern around the world. Rapid increase in the emergence of multidrug-resistant bacteria has been the target of extensive research efforts to develop a novel class of antibiotics. Antimicrobial peptides (AMPs) are small cationic amphiphilic peptides, which play an important role in the defense against bacterial infections through disruption of their membranes. They have been regarded as a potential source of future antibiotics, owing to a remarkable set of advantageous properties such as broad-spectrum activity, and they do not readily induce drug-resistance. However, AMPs have some intrinsic drawbacks, such as susceptibility to enzymatic degradation, toxicity, and high production cost. Currently, a new class of AMPs termed “peptidomimetics” have been developed, which can mimic the bactericidal mechanism of AMPs, while being stable to enzymatic degradation and displaying potent activity against multidrug-resistant bacteria. This review will focus on current findings of antimicrobial peptidomimetics. The potential future directions in the development of more potent analogs of peptidomimetics as a new generation of antimicrobial agents are also presented. © 2014 Méndez-Samperio.

Demigha O.,Polytechnic School of Algiers | Hidouci W.-K.,Ecole Nationale Superieure dInformatique | Ahmed T.,University of Bordeaux 1
IEEE Communications Surveys and Tutorials | Year: 2013

Energy-efficiency in target tracking applications has been extensively studied in the literature of Wireless Sensor Networks (WSN). However, there is little work which has been done to survey and summarize this effort. In this paper, we address the lack of these studies by giving an up-to-date State-of-the-Art of the most important energy-efficient target tracking schemes. We propose a novel classification of schemes that are based on the interaction between the communication subsystem and the sensing subsystem on a single sensor node. We are interested in collaborative target tracking instead of single-node tracking. In fact, WSNs are often of a dense nature, and redundant data that can be received from multiple sensors help at improving tracking accuracy and reducing energy consumption by using limited sensing and communication ranges. We show that energy-efficiency in a collaborative WSN-based target tracking scheme can be achieved via two classes of methods: sensing-related methods and communication-related methods. We illustrate both of them with several examples. We show also that these two classes can be related to each other via a prediction algorithm to optimize communication and sensing operations. By self-organizing the WSN in trees and/or clusters, and selecting for activation the most appropriate nodes that handle the tracking task, the tracking algorithm can reduce the energy consumption at the communication and the sensing layers. Thereby, network parameters (sampling rate, wakeup period, cluster size, tree depth, etc.) are adapted to the dynamic of the target (position, velocity, direction, etc.). In addition to this general classification, we discuss also a special classification of some protocols that put specific assumptions on the target nature and/or use a non-standard hardware to do sensing. At the end, we conduct a theoretic comparison between all these schemes in terms of objectives and mechanisms. Finally, we give some recommendations that help at designing a WSN-based energy efficient target tracking scheme. © 2013 IEEE.

This paper aims to discuss the use of the Coats-Redfern equation to determine the kinetic parameters of pyrolysis processes of long flame coal by Lin et al. (2014). The original paper has presented the incorrect Coats-Redfern kinetic model to compute the activation energy and the frequency factor. However, this discussion gives the correct Coats-Redfern equation with some clarifications and elucidations. © 2016 Elsevier Ltd.

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