This paper presents a statistical analysis of reported accidents related to the Skikda’s Oil and Gas Refinery that led to a major explosion and loss of life. A historical review of fire, explosion and toxic release incidents that occurred during the period between 2002 and 2013 is presented. A brief description of each accident/incident is provided with the fatalities and personal injuries that resulted being described. These case studies have been analyzed with a view to understand the common causes including errors, which have led to catastrophic events. Accident frequency analysis has been applied to various types of primary accidental events such as fire, explosion and toxic gas releases to assess the potential damage of such events and the likelihood of such damage occurring. The basic principles of such analysis is to utilize the available information and use the most detailed elements to illustrate what the industry should learn from these accidents so that it can learn from them and hopefully prevent future major accidents.

Prediction of soil swelling characteristics and accurate quality estimation can be of a great consideration and contribution regarding the site stability. Any concerned investigation is correspondingly an advanced priority for the project realization. Related inquiries allow potential reduction concerning financial and technical charges damage prior to any urban development. The determination of soil characteristics lead for a better recognition, and allow to make the best choice of foundation type adopted for each site. Thus, in any urban case study, much gain can be made by team work recording and surveying the related data. In the considered city of El Kouif, located in Tebessa (Algeria), several buildings have been mainly built on expansive soils. Observations indicate different severe damages which were caused mostly in the nearby structures. These damages are characterized by deflection and failure of walls. Lateral and vertical displacements evidences support the presence of shear movements and subsidence. The scale up of these movements occurrence can reach millimetric shifting dimension. Ground and subsurface risk activity affecting El Kouif city site are also related to the presence of destructive chemical components such as sulfates. The sulfate occurrence is illustrated through generally gypsum minerals concentration present in the concerned soil. During building projects, these soils, in meeting concrete and in presence of water, are source of new mineral generation such as ettringite. It consists on the assemblage of water and sulfate in addition to calcium. Source for these chemical products expansion might be associated to historical event: the city of El Kouif was the field of phosphates mining area in addition to established phosphate extraction plant. Thus, determination of soil characteristics and involvement of chemical components turn out to be the main objectives in this investigation.

In machining operation, the quality of surface finish is an important requirement for many turned work pieces. cutting temperature is one of the most important parameters in determining the cutting performance and tool life. the objective for this work is to estimate the cutting temperature in 3D model on tool-chip interface and the interface temperature during turning process, using the digital simulation software COMSOL Multiphysics.The tool–chip interface temperature results obtained from experimental results by using C45 medium carbon steel work piece with natural contact tools, without the application of cooling and lubricating agents and a K type thermocouple technique was used for estimating cutting temperatures in a turning operation.This procedure facilitates the determination of the temperature at tool-chip interface in dry turning process, which is still a challenge for existing experimental and numerical methods.

This paper presents an intelligent control strategy that uses a feedforward artificial neural network in order to improve the performance of the MPPT (Maximum Power Point Tracker) MPPT photovoltaic (PV) power system based on a modified Cuk converter. The proposed neural network control (NNC) strategy is designed to produce regulated variable DC output voltage. The mathematical model of Cuk converter and artificial neural network algorithm is derived. Cuk converter has some advantages compared to other type of converters. However the nonlinearity characteristic of the Cuk converter due to the switching technique is difficult to be handled by conventional controller. To overcome this problem, a neural network controller with online learning back propagation algorithm is developed. The NNC designed tracked the converter voltage output and improve the dynamic performance regardless load disturbances and supply variations. The proposed controller effectiveness during dynamic transient response is then analyze and verified using MATLAB-Simulink. Simulation results confirm the excellent performance of the proposed NNC technique for the studied PV system. 

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.

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.