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.

In this paper, first we show that the analytical solutions obtained in  the literature for the new coupled Konno-Oono system can be immediately presented  via the Weierstrass elliptic function or Jacobi elliptic functions. Next, we present a  new general real dark-type of soliton and a complex bright-type of envelope soliton  to this system in terms of the solutions of the sine-Gordon and sinh-Gordon equations  involving an arbitrary function via two new different transformations.

The main idea of this study is to evaluate the estimation performance of extended and unscented Kalman filters (EKF and UKF). So, these latter are introduced to estimate the dynamic states of a similar model operating with identical covariance matrices in the same situation. The mean square error (MSE) criterion is used to quantify the estimation error between the actual and the estimated values. The simulation results obtained with Matlab/ Simulink software confirm the superiority and efficiency of UKF over EKF, especially when the system is highly non-linear under process and measurement noises, such is the case of the inverted double pendulum mounted on a cart (DIPC).

This paper proposes a new approach of multi-spectral image compression based on the combination of the particle swarm optimization (PSO) and the discrete wavelet transforms (DWT). In the first stage, the PSO is used to reduce the redundancies in the spectral domain. In fact, the PSO transforms a given multispectral image to optimize the energy in the first band. Despite to the complexity of this kind of approach, the transformed multispectral image is easily computed by multiplying a de-correlation matrix and the input multispectral image. The de-correlation matrix is estimated via a PSO evolution derived by a defined fitness function. In the second stage, the compressed data, related to the input multispectral image, is computed from the transformed multispectral image using an efficient 2D-DWT based algorithm. In addition to this compression approach, the original multispectral image can be recovered using a decompression algorithm. Experimental results show the validity of our proposed approach. These significant results are evaluated according to Peak signal-to-noise ratio (PSNR), compression ratio (CR) and bits per pixel (bpp) metrics.

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.

As a key wind turbine element, the blade is a determining factor for reliability and efficiency of the turbine system and a main source of complicated and critical loads. In this present investigation, the strength behavior of a small composite blade for H-type Darrieus wind turbine was studied. Firstly, three-dimensional (3D) modelling of the blade structure with NACA 0018 airfoil profile was established. Secondly, the Finite element analysis (FEA) technique was conducted to perform the strength analysis of the blade structure subjected to extreme climatic conditions by means SOLIDWORKS SIMULATION software. This analysis was performed to identify the resistance, stiffness and reliability of the composite blade structure. The results from FEA identify that the structure of the blade will not be subjected to structural failure during WT operation (0 ~ 19 m/s) according to maximum principal stress equivalent (von Mises) and maximum displacements.

L'article décrit la conception et la mise en œuvre en temps réel d'une commande non linéaire appliquée à un système de conversion de l'énergie éolienne (SCEE). La commande backstepping a été mise en œuvre pour améliorer les performances du système de conversion éolienne basé sur un générateur synchrone à aimants permanents (PMSG) connecté au réseau. Deux convertisseurs statiques assurent la connexion au réseau et sont contrôlés par la modulation de largeur d'impulsion (MLI). L'algorithme de contrôle proposé assure un contrôle de vitesse adéquat pour extraire la puissance maximale. Une description détaillée des lois de contrôle du backstepping basées sur la technique de stabilité de Lyapunov a été exposée. Les résultats obtenus par l'application de cette approche ont clairement répondu aux exigences de robustesse et de suivi des références même dans des conditions de vent fluctuants, et ont confirmé l'efficacité d'un tel contrôle dans les modes de fonctionnement statique et dynamique.

The turbine blades are subjected to high operating temperatures and high centrifugal tensile stress due to rotational speeds. The maximum temperature at the inlet of the turbine is currently limited by the resistance of the materials used for the blades. The present paper is focused on the thermo-mechanical behavior of the blade in composite materials with reinforced mast under two different types of loading. The material studied in this work is a composite material, the selected matrix is a technical ceramic which is alumina (aluminum oxide Al₂O₃) and the reinforcement is carried out by short fibers of high modulus carbon to optimize a percentage of 40% carbon and 60% of ceramics. The simulation was performed numerically by Ansys (Workbench 16.0) software. The comparative analysis was conducted to determine displacements, strains and Von Mises stress of composite material and then compared to other materials such as Titanium Alloy, Stainless Steel Alloy, and Aluminum 2024 Alloy. The results were compared in order to select the material with the best performance in terms of rigidity under thermo-mechanical stresses. While comparing these materials, it is found that composite material is better suited for high temperature applications. On evaluating the graphs drawn for, strains and displacements, the blade in composite materials reinforced with mast is considered as optimum.

Volunteer computing (VC) has become a relatively mature technique of distributed computing. It is based on exploiting the idle time of ordinary online machines with the consent of their owners. Target applications are generally scientific projects requiring a huge amount of computational resources. Existing VC platforms raise several challenges. This work attempts to bring solutions for two defeats. The first one is the involvement of volunteers; the decreasing of participants affects the global performances. To cope with this, a new social volunteer computing environment is proposed in order to involve more volunteers. The second addressed problem is the task scheduling, which aims to optimize the use of resources. The proposed algorithm generates for each resource's class, a number of tasks whose cost of execution reflects the momentary capacity of the resources. The new solutions are validated through a theory of number's project, called “Collatz Conjecture.”

Introduction

The analysis of electrocardiogram (ECG) signals allows experts to diagnose several cardiac disorders. However, the accuracy of such diagnosis depends heavily on the signal quality. In this paper, an efficient method based on fractional wavelet decomposition coupled with thresholding techniques is proposed for noise removal.

Methods

The usual low-pass and high-pass filters of the wavelet transform are replaced by fractional-order ones. Thus, fractional wavelets are proposed, simulated, and compared to other wavelets for ECG denoising. The denoising process was made operational by the means of an appropriate choice of the wavelet transform coefficient thresholding and the wavelet decomposition level of the signal.

Results

Considering the relative error metrics, the best wavelet function for efficient denoising is the fractional one. In our study, we have used eight real ECG signals from the Physionet MITBIH. In order to prove the effectiveness of our method, we investigated the filtering of two types of noises, namely Gaussian white noise and power-line interference (PLI) noise. The proposed method removed the Gaussian white noise completely and had better performance on the PLI noise. Considering classical metrics of assessment, results show the advantage of the proposed method compared to other types of wavelets.

Conclusion

The proposed method is the most suitable one for removing PLI and Gaussian white noise from ECG signals with superior performance than other wavelets. Also, it can be applied for high-frequency denoising even without a priori frequency knowledge.

Research on risk matrices show that there is considerable diversity in the practice of designing risk matrices. This has led to serious problems of standardization and communication. Indeed, these problems affect at the same time on the development of matrices and in their exploitation in term of risk assessment. To solve these problems, this paper proposes an experience feedback method that aims to capitalize the feedback invariants resulting from the analysis of existing risk matrices. This capitalization allows developing a theoretical framework of the robust risk matrices design. The application of the proposed method for examples of matrices confirms the interest of articulating these risk matrices designs through an argument based on experience feedback. In this sense, the merit of the proposed experience feedback method is that it promotes the sharing of knowledge between the actors involved in a risk assessment.

The ageing of the Algerian oil and gas (O&G) installations has led to many incidents. Such installations are over 30 years old (life cycle) and still in operation. To deal with this O&G crucial problem, the Algerian authorities have launched a rehabilitation and modernization schedule of these installations. Within the framework of this program, many audit operations are initiated to elaborate a general diagnosis of the works to be performed while optimizing production. In other words, industrial ageing risks shall be controlled. In the process safety management (PSM) context, the aim of this paper is to study ageing problem of the Algerian industrial installations through proposed indicators. Their prioritization adjusted by (TOPSIS) Technique for Order-Preference by Similarity to Ideal Solution method which allows identification of ageing control solutions of Algerian onshore fields.