The multilevel multi-string inverter has gained much attention in recent years due to its advantages in lower switching loss, better electromagnetic compatibility, higher voltage capability, and lower harmonic distortion. Solar Energy is one of the favorable renewable energy resources and the multilevel inverter has been proven to be one of the important enabling technologies in photovoltaic (PV) utilization. As the number of levels increases, it is important to control more switches in parallel with their concurrent processing capability. This paper proposes an IGBT clamped three phase nine levels photovoltaic inverter topology with a multicarrier dual reference pulse-width modulated (PWM) control scheme. Four carrier waves of the fundamental frequency and different amplitudes are compared with two references (a sine wave and its opposite) for generating the control signals of the switches. Some DC/DC boost converters are used to amplify the voltage produced by the photovoltaic generators. Each of these converters is controlled by an MPPT algorithm in order to track the maximum power point of the GPV. Results of simulation in Matlab environment are given and discussed.

 In this study, single crystal Ge layers have been deposited by molecular beam epitaxy on PSi substrate, with different thicknesses (40 nm and 80 nm) at the growth temperature of 400°C. Raman and Atomic force microscopy (AFM) have been applied for investigation of photoluminescence, structural and morphological properties of the Ge on PSi layers. The results show a stronger Raman intensity of PSi due to change of its optical constant. Similarly the Si/Ge/PSi sample shows a peak at 399 cm-1 but with lower intensity compared with that of PSi probably due to the Si emission partially covered by the Ge inside the pores. Besides that a sharp Raman peak at 298 cm-1 is observed which reflects Raman active transverse optical mode of the introduced Ge which indicates the growth of Ge with good crystallinity. AFM characterization shows the rough silicon surface which can be regarded as a condensation point for small skeleton clusters to form, with different size of pores. These changes are highly responsible for its photoluminescence in the red wavelength range. This study explores the applicability of prepared Ge/PSi layers for its various applications in advanced optoelectronics field and silicon-on-insulator applications.

In this study, single crystal Ge layers have been deposited by molecular beam epitaxy on PSi substrate, with different thicknesses (40 nm and 80 nm) at the growth temperature of 400°C. Raman and Atomic force microscopy (AFM) have been applied for investigation of photoluminescence, structural and morphological properties of the Ge on PSi layers. The results show a stronger Raman intensity of PSi due to change of its optical constant. Similarly the Si/Ge/PSi sample shows a peak at 399 cm-1 but with lower intensity compared with that of PSi probably due to the Si emission partially covered by the Ge inside the pores. Besides that a sharp Raman peak at 298 cm-1 is observed which reflects Raman active transverse optical mode of the introduced Ge which indicates the growth of Ge with good crystallinity. AFM characterization shows the rough silicon surface which can be regarded as a condensation point for small skeleton clusters to form, with different size of pores. These changes are highly responsible for its photoluminescence in the red wavelength range. This study explores the applicability of prepared Ge/PSi layers for its various applications in advanced optoelectronics field and silicon-on-insulator applications.

In this study, single crystal Ge layers have been deposited by molecular beam epitaxy on PSi substrate, with different thicknesses (40 nm and 80 nm) at the growth temperature of 400°C. Raman and Atomic force microscopy (AFM) have been applied for investigation of structural and morphological properties in order to explain the photoluminescence properties of the Ge on PSi layers. The results show a stronger Raman intensity of PSi due to change of its optical constant. Similarly, the Si/Ge/PSi sample shows a peak at 399 cm-1 but with lower intensity compared with that of PSi probably due to the Si emission partially covered by the Ge inside the porous. Besides that, a sharp Raman peak at 298 cm-1 is observed which reflects Raman active transverse optical mode of the introduced Ge which indicate the growth of Ge with good crystallinity. AFM characterization shows the rough silicon surface which can be regarded as a condensation point for small skeleton clusters to form, with different size of pores. These changes are highly responsible for its photoluminescence in the red wavelength range. This study explores the applicability of prepared Ge/PSi layers for its various applications in advanced optoelectronics field and silicon-on-insulator applications.

Nowadays, communications networks becomes an essential tool for exchange information. This fact allows having robust systems that ensures secure transfers against arbitrary intrusion. In literature, we encounter various encryption schemes that meet this requirement. In this paper, we interest to the chaos cipher map that achieved image encryption and its resistance against attacks based on genetic algorithm, an efficiency bio-inspired heuristic that used as powerful tool for resolution of complex combinatory problems. The skill of the approach is the use of such heuristic, and for a first time, in attack of image encryption schemes. We show its effectiveness by reporting results of some preliminary experiments, including a comparison with brute force attack.

The basin of Timgad is located in the Aures. It is characterized by an average annual precipitation which reaches 800 mm. Hydrology tributary of the relief is the direct result of surface water and snowmelt from the heights of the Massif of Chélia. The origin of groundwater: semi-deep to deep aquifer is mainly from the infiltration of precipitation in the geological layers. This rock forms a water table that is intersected by drilling to a depth of 137-400 m giving a flow rate of 6 l / s. and white fractured sandstone forming a confined aquifer 190 m with a flow rate of 28 l / s. The check of geo-electric results of the basin show that the Miocene and Cretaceous layers have important thickness, they are heterogeneous and may contain large aquifer at different levels. The influence of vertical normal faults makes possible an exchange of waters between theses aquifers. The implementation of dam project in the basin will minimize the silting, regulate the flow rate, and contribute to the irrigation of the plain, it can be used for industry too. The objective of this approach is the mobilization of surface water resources decided by the government for a rational and planned of this vital factor which is water. Caractérisation géologique, hydrologique et hydrogéologique du bassin de Timgad (Aurès, Algérie NE), pour la mobilisation des ressources hydriques Résumé : Le bassin de Timgad est située dans les Aurès. Il est caractérisé par une moyenne annuelle des précipitations de l’ordre de 800 mm. L’hydrologie tributaire du relief est la conséquence directe des eaux de surface et de la fonte des neiges provenant des hauteurs du massif de Chélia. L’alimentation de l’eau souterraine des différentes nappes phréatiques profondes à semi-profonde provient essentiellement de l’infiltration des eaux de pluies dans les couches géologiques. Ce cortège de roche forme une nappe libre qui est recoupée par des forages sur une profondeur de 137-400 m fournissant un débit de 6 l/s. et des grés blancs grossiers fracturés formant une nappe captive à 190 m avec un débit de 28 l/s. L’examen des coupes géoélectriques du bassin montrent que les formations du miocène et du crétacé sont dont l’ensemble, épais, hétérogène et susceptible de contenir de grandes potentialités d’aquifères à des niveaux différents. L’influence de failles normales verticales rend possible une éventuelle alimentation des aquifères entres eux. L’importance de l’implantation d’ouvrage de retenue dans le bassin est de minimiser le phénomène d’envasement, de réguler le débit d’écoulement et de contribuer à l’irrigation de la plaine ainsi que l’alimentation des briqueteries. L’objectif de cette approche, est la mobilisation des ressources en eaux superficielles décidée par l’état en vue d’une utilisation rationnelle et planifiée de ce facteur vital qui et l’eau.