The mast support for small vertical axis wind turbine is considered an important parameter during the design process of wind turbine structure. It has been receiving a great attention by researchers and academics. This study presents a numerical investigation on the static and buckling strength behaviors of whole wind turbine mast structure by means Finite Element Analysis (FEA) technique. The FEA simulations are performed in order to evaluate the reliability and the strength of the mast structure under the extreme wind conditions (IEC 61400-2 and Eurocode 1991-1-4 standards) and gravity loads. The simulation results show that the mast structure will not undergo structural failure because the maximum stress induced is less than the yield strength of the material and the maximum displacement is within material allowable deformation limit. In addition, the buckling strength of the structure meets requirement of design.
Abdelfateh K, Mohamed BAHEDDI, Fattah MY. Numerical Modeling of the Pipeline Uplift Mechanism in Clay. Archives of Hydro-Engineering and Environmental MechanicsArchives of Hydro-Engineering and Environmental Mechanics. 2021;68 :119-135.
The emergence of remote sensing images with high spatial resolution has increased the advancement of image-based information extraction methods. One of the rapidly developing approaches for mapping and analyzing high spatial resolution images is the object-based approach, also known as geographic object-based image analysis (GEOBIA). This development makes it possible to quickly and accurately distinguish between vegetated and non-vegetated objects in vegetation study. This study aims to (1) create a ruleset to discriminate vegetated and non-vegetated objects from a high spatial resolution image, (2) apply the GEOBIA approach to map vegetated and non-vegetated objects, and (3) calculate the accuracy of the mapping results. The GEOBIA approach was applied to a WorldView-2 image (2 m pixel size and eight multispectral bands) of the Clungup Mangrove Conservation area, Malang, East Java, Indonesia. We assessed the ability of all of the WorldView-2 image bands for discriminating the targeted objects. The segmentation process in GEOBIA used a multi-resolution segmentation algorithm using the normalized difference vegetation index (NDVI), and the image classification used a rule-based classification technique. The green, red, and near-infrared bands can effectively distinguish the targeted objects based on the developed ruleset. The classification result shows that the vegetated and non-vegetated classes fall within their corresponding objects on the image. We implemented an area-based accuracy assessment that assesses both positional and thematic accuracy of the mapping result, based on the visual interpretation of the pansharpened WV-2 image (0.5 m pixel size) as a reference for the accuracy assessment. This process results in a 74,06% accuracy, meaning that the combination of GEOBIA and WorldView-2 image produces high accuracy of vegetated and non-vegetated objects map.
De nos jours, la plupart des moteurs d’analyse de solutions anti-malware sont heuristiques. Ils classent les objets, les flux de données ainsi que les zones mémoires comme bénins ou malveillants en fonction de leur comportement. La plupart des fabricants d’antivirus reconnaissent que l’approche heuristique permet d’atteindre jusqu’à 90% d’efficacité en termes de taux de détection, mais consomme davantage de ressources systèmes : de tels moteurs anti-malware, disponibles en open-source, sont extrêmement inefficaces en termes d’utilisation de ressources système car ils font souvent appel à des algorithmes d’apprentissage automatique. Pour réduire cette charge système, il est fortement recommandé d’utiliser la détection par signature statique, qui permet de filtrer à elle seule la majorité des échantillons de programmes malveillants connus, en conjonction avec les technologies de détection heuristiques et celles basées sur le cloud. Dans ce travail, nous présentons un scanner de signatures rapide pour la détection de programmes malveillants, basé sur une version améliorée de l’algorithme Aho-Corasick pour la recherche de cha{\^ınes de caractères (ou motifs), con\c cue pour pouvoir bénéficier des techniques de vectorisation qui ajoutent une forme de parallélisme de données au code de l’algorithme. La solution proposée est implémentée en utilisant le jeu d’instructions d’Intel® Advanced Vector Extensions (AVX2).
The exploitation of fossil fuels is causing global warming whose negative effects have recently been felt all over the world. Therefore, the search for new sources of energy, renewable and respectful of the environment is crucial for manufacturers. The concept of Best Available Techniques (BAT) presents an adequate solution for manufacturers, for the control, elimination or reduction of the harmful impacts of their activities on the environment. This concept, known as Integrated Pollution Prevention and Control (IPPC), was introduced and imposed from 1996 in Europe. This paper aims to introduce the possibility of transferring the IPPC approach and BAT concepts to Algeria. Therefore, the main objective is to propose some recommendations to optimize the technical and environmental performance of hybrid solar-gas systems, by treating as a case study the first hybrid solar-gas power plant SPPI (Solar Power Plant One) near Hassi R’mel in the south of Algeria. A gap analysis of the Algerian environmental policy compared to the IPPC system, and an assessment of technical and environmental performance of the “SPPI” plant in terms of regulation and BAT are developed in our study.
