To enhance the robustness and dynamic performance of a self-excited induction generator (SEIG) used in a stand-alone wind energy system (WES), a virtual flux oriented control (VFOC) based on nonlinear super-twisting sliding mode control (STSMC) is adopted. STSMC is used to replace the conventional proportional-integral-Fuzzy Logic Controller (PI-FLC) of the inner current control loops. The combination of the proposed control strategy with space vector modulation (SVM) applied to a PWM rectifier brings many advantages such as reduction in harmonics, and precise and rapid tracking of the references. The performance of the proposed control technique (STSMC-VFOC-SVM) is verified through simulations and compared with the traditional technique (PI-FLC-VFOC-SVM). It shows that the proposed method improves the dynamics of the system with reduced current harmonics. In addition, the use of a virtual flux estimator instead of a phase-locked loop (PLL) eliminates the line voltage sensors and thus increases the reliability of the system.

Multi-agent systems research community has developed solutions to model dynamic and complex systems. Those solutions have generated a growing interest in a variety of domains such as robotics or distributed controls. It is therefore important to build solutions to analyze the basic mechanisms of multi-agent systems such as interaction. In this paper, we formalize the epistemic interaction, we propose to use default theory to describe state transitions. The introduction of such semantics allows characterizing the verification of agent behavior when dealing with new information. Therefore, we introduce semantics to establish a basis for exploiting the properties of the agent behavior and its messages.We propose to formalize and verify the response of an agent when it receives a new information from another agent of its environment. Our approach extends the actions initiated in the mA ^* [5] language by applying the Reiter’s default rules [32]. A simple example is used to illustrate our approach.

Considering three sites under different climate conditions (arid, semi-arid, and subhumid), this study aims to use the vadose-zone water stable isotope profiles to estimate the groundwater recharge rate. High-resolution vertical subsurface soil sampling along the vadose zone of the investigated sites was conducted. The collected samples were analysed to determine their stable isotope ratios (δ²H and δ¹⁸O) that were used along with the piston displacement method to estimate recharge. Annual recharge rates of 0.2% (± 0.1%), 2.5%, and 18% of the total annual precipitation were obtained for the arid, semi-arid, and subhumid sites, respectively. Recharge rates at the semi-arid and subhumid sites are comparable to those previously estimated using water balance-based methods. The recharge rate at the arid site is lower than that previously estimated for that site using the water budget-based method, revealing difficulties in applying the piston displacement method under an arid regime.

The present study aimed to investigate the potential protective effects of zinc (Zn) against hexavalent chromium-induced hepatotoxicity in pregnant Wistar rats. Female rats were treated subcutaneously (s.c) on the 3 rd day of pregnancy, with NaCl 0.9 % and served as control, K₂Cr₂O7 (10 mg/kg bw) alone, or K₂Cr₂O7 in association with ZnCl2 (20 mg/kg bw). Hepatic biochemical parameters, oxidative stress biomarkers and DNA damage were monitored. Results revealed that K₂Cr₂O7 disturbed plasma ALT, AST, ALP and GGT, induced hepatic oxidative stress and DNA fragmentation. The co-treatment with Zn has alleviated K2Cr2O7-induced hepatotoxicity by exhibiting antioxidant and genoprotective effects in pregnant Wistar rats.

Some epidemiological situations, because of their magnitude and their propagation dynamics, can escape local or national control. For example, the world is currently experiencing an uncontrollable cross-border spread of the corona virus (Covid-19). The Wilaya of Batna is among the most affected in Algeria by many epidemiological diseases, including tuberculosis, which raises questions about possible causal links between this contagious and often fatal disease and the environmental and socio-economic reality of this territory. We based our study on a number of factors, covering economic, societal and health aspects, which constitute indicators of the standard of living in each of the 61 communes of the Wilaya of Batna. The relationship between the epidemiological status of tuberculosis in these communes and these indicators showed significant correlations and thus confirmed the reliability of the choice of parameters of vulnerability to tuberculosis. To understand their interaction and impact on the disease and its spatial distribution, we used the hierarchical multicriteria analysis (AHP) method, the results of which were implemented in a GIS database. The aim was to provide health and territorial decision makers with a decision support tool. The results show that the spatial distribution of tuberculosis cases which reappeared in the Wilaya of Batna after its eradication since years is in good correlation with the socio-economic situation of each commune of the territory and confirm that this scourge of tuberculosis is closely linked to the degradation of the living conditions of the inhabitants.

In the last decade, the number of diabetic persons has considerably increased and the scientific community approach to understand this complex pathology has become very difficult due to the fact that diabetes is linked to other illnesses which can generate serious complications like glaucoma, nerve damage. Plants are considered new alternative resources to treat various pathologies including type 2 diabetes, and several research works showed that it is significantly more accurate to use Oral Glucose Tolerance Test (OGTT) when diagnosing diabetes which prompted us to adopt this model to evaluate the possible anti-hyperglycemic effect of n-BuOH extract of Centaurea tougourensis. More than 500 Centaurea species are distributed in Mediterranean and West Asia zones. These species demonstrated over the years their pharmacological potential like antioxidant, anti-microbial, anti-diabetic, cytotoxic, activities due to their richness in secondary metabolites. A Preliminary phytoscreening was first done to identify the most important secondary metabolites in the plant and revealed the presence of key classes like; tannins, flavonoids, triterpenes… The pre-treatment of mice group by the dose of (400 ml/kg, p.o) of plant extract resulted in a significant (P<0.01) decrease of hyperglycemia (1.32 ± 0.06 g/l) 60 min after the induction of a temporary diabetes with a maximum percentage inhibition of (37%) while the reference group treated by Glibenclamide (10 mg/kg, i.p.) was only (31%) the same time. This concluded that C. tougourensis stabilized the blood glucose level and may have the potential to treat other pathologies.

Cet article est consacré à l’étude des performances de la génératrice asynchrone à cage double étoile (GASDE) en site isolé. Le système de commande est composé d’une GASDE raccordé à un bus continu et une charge en sortie de deux redresseurs à commande MLI. Une étude comparative entre la technique de commande conventionnelle et la commande adaptée basée sur l’introduction de la SVM-PI-flou et un nouvel estimateur de flux (flux virtuel statorique) afin d’améliorer la qualité d’énergie et d’atténuer les harmoniques du courant

In the petroleum industry, equipments must be maintained properly to meet the adequate reliability standards in order to achieve the desired business goals in terms of productivity, safety and environmental protection. This article offers a new approach focused on risk analysis to select a better maintenance strategy. The proposed approach consists of three stages. In the first step, we identify the accident scenarios that could lead to the loss of production and damage to the environment. In the second step, we estimate the frequency of occurrence of these scenarios. In the third step, we calculate the economic losses and environmental taxes. Finally, an appropriate maintenance strategy is proposed, taking into account the evaluation results obtained by the previous steps. A case study illustrates the proposed approach and shows that the latter constitutes an important decision support tool to improve the existing maintenance strategy to comply with regulations and standards in term of productivity, reduction of costs and environmental protection

This study aims to assess the diversity and distribution of fungal mycoflora developing on Cedrus atlantica (Endl) G. Manetti ex Carrière needles in three sites in the Belezma National Park (Biosphere Reserve, Northeast - Algeria). Three sites were sampled according to a cedar decline gradient, these are the massifs of: Telmet (healthy site), Boumerzoug (moderately depressed) and Tougurt (decayed site). Polymerase chain reaction (PCR) molecular analysis, allows identifying 19 endophytic mycotaxa. All the identified species have a weak occurrence frequency (less than 25%). In terms of specific richness, the moderately depressed site (Boumerzoug) homes the largest number of taxa (S = 17), followed by healthy site of Telmet (12 taxa), while the depressed site of Tougurt was the least populated (8 taxa). The hierarchical classification analysis (HCA) showed that the taxonomic composition of endophyte associations differs clearly from one site to another according to the cedar decline. The clustering representing healthy massif brings 2 species which are demanding phytoparasitic endophytes (Fusarium sp. and Xylaria sp.). The group associated to moderately depressed site hosts 7 taxa with a wide ecological valence, such as: Canariomyces notabilis, Canariomyces vonarxii, Chaetomium aegilopis, Coniolariella hispanica and Penicillium kubanicum. Then, mycoflora group noted in the decayed cedar includes 10 taxa, in particular, saprophytic mycotaxa relatively less demanding with a high ecological valence like: Biscogniauxia mediterranea, Alternaria arborescens, A. tenuissima and three species of Chaetomium genus. The mycotaxa distribution is related to the specific conditions of colonized trees. Taxa specific to healthy and decayed massifs would represent bio indicators of the phytosanitary and ecological conditions of colonized cedars.