In most industrial environments, vibration analysis is widely used for fault diagnosis of rolling bearings. The vibration signal measured from a bearing represents a mixture of motor vibration, rolling vibration, noise, and other sources. Due to the high cost of devices and limited space, only one sensor can be installed to measure this signal. In this paper, a feature extraction method based on Single Channel Blind Source Separation (SCBSS) and Normal Distribution (ND) is proposed for vibration monitoring of rolling element bearings. To decompose the bearing signal, SCBSS is applied for separating the different sources. Because ND is sensitive to the type of fault, it is used as criterion to find an output that contains the maximum information about the fault by removing the other sources. In fact, the obtained signal contains other vibrations which affect the correct source of fault. A second SCBSS filter is, therefore, proposed to decompose the selected source and thus improves the performance of fault diagnosis. The application of the proposed method is carried out on a deep groove ball bearing with outer race fault, ball fault, and inner race fault in order to better validate the diagnosis results.

This paper proposed a new strategy of sinusoidal pulse width modulation (SPWM) technique to control three-phase nine-level switched-capacitor inverter (9LSCI) in grid-connected PV systems. The main advantage of this inverter is high voltage gain, achieved by switching the capacitors in series and parallel to boost up the output voltage using low voltage input. To improve the quality of solar energy for injection into the electrical grid, a rooted tree optimization (RTO) algorithm is used to get optimum values of initial angles of multi carriers SPWM technique, giving the lowest possible values of the total harmonic distortion (THD). The design also can maximize the efficiency of the multi-level inverter by minimizing its size using fewer components and a single DC source and reducing the rate of THD. The higher effectiveness and accuracy of the suggested RTO-SPWM technique was tested and verified in comparison to existing classical SPWM technique from the performance of PV-grid systems that it can effectively reduce the total harmonic distortion to 0.16 %.

This article deals with the problem of blind separation of statistically independent sources from the instantaneous linear model (n × n). When the observation signals are affected by the additive white gaussian noise (AWGN), the implementation of the proposed solution is performed by following three steps. The first step is a whitening process. The second step aims to convert the uncorrelated signals into statistically independent signals. The last step consists in reducing the noise existing in the noisy estimations. The main part of the proposed solution is to determine the adequate rotating angle (θ) that maximizes the kurtosis of the whitened signals. This rotating angle is obtained through the use of optimization techniques by applying a genetic algorithm. The proposed solution has the advantage of not converging to a local maximum, and also the separation method can be easily generalized to converge directly towards the global maximum for the case of several sources. The results obtained by applying many simulations, prove the effectiveness and the performance of the proposed method even in the noisy case and whatever the type of the signals (stationary or non-stationary).

This paper seeks to explore the Algerian EFL learners’ beliefs about, and attitudes towards, promoting Learner Autonomy (LA) via the implementation of Collaborative Learning (CL) as a teaching method. The study was carried out at the Department of English of Mostefa Benboulaid Batna 2 University during the academic year 2018-2019. To meet the paper’s objectives, a quantitative approach was opted for where an adapted questionnaire was administered to the first-year students. The overall results revealed the positive disposition of the Algerian EFL learners towards the use of the CL teaching method as a channel to develop their autonomy.

According to several American and European scholars, intellectuals, and media experts in U.S. foreign policy, the American national security strategy had witnessed a reformulation in the 21st century after the 9/11 attacks. In reality, never after Pearl Harbor, America has experienced such a dramatic security event. For which the obvious question remains posed: President Bush’s National Security Strategy marked a new path to a universal American security measure? Did it develop a new policy process with new norms to fit the modern era? Accordingly, U.S. military intervention in Afghanistan aims to preserve; freedom, liberal values, deter terrorism, and protect the threatened American security; hence, we have come with this study to evidence that by the fact that Bush's unilateral preventive war strategy, which witnessed a blatant violation of International Law, Human Rights, and the United Nations Charter of State’s sovereignty, was no more than the natural reaction to their foreign policy adoption of duplicity. The American National Security Policy is, in reality, an overtly way of military expression policy to enforce duplicity.

Les mouvements de protestation populaires contemporains semblent partager deux caractéristiques : l'une est discursive et l'autre est médiologique. Sur le plan du discours, des constantes énonciatives et sémantiques traversent les mouvements en question. Sur le plan médiologique, ce sont des mouvements favorisés et facilités par des « embrayeurs médiologiques » que cette contribution se propose de mettre en évidence.

Polluted water poses significant health risks when it is part of the water sources used for irrigation, leading to the contamination of soil and plants by various pollutants. This work aims, firstly, to assess the degree of pollution of Wadi El Gourzi water (Batna, Algeria), and then to verify the consequences on their use for the irrigation of market garden plants for everyday consumption (lettuce, cilantro, parsley and spinach), both in the aerial part (stems and leaves) and in the soil where they are grown. This study focuses on trace metals (Cr, Pb, Zn and Cd). Soil pollution was assessed by calculating the soil pollution index (PI), while the uptake of these elements by plants was monitored by the transfer factor (TF). The analyses of the Wadi El Gourzi water with the flame atomic absorption spectrophotometer (FAAS) show a maximum abnormal concentration of Cr (17.37 mg∙dm–3), Pb (0.71 mg∙dm–3) and Cd (0.45 mg∙dm–3). For the analysis of the soils irrigated by these waters, the results of the PI show that the soils used for the cultivation of parsley and lettuce are polluted by several metals (PI > 1). The concentrations of trace metals elements (TMEs) in the sampled plants show a significant accumulation of Zn, Cd, Pb and Cr by the vegetables (coriander, parsley, spinach and lettuce). These concentrations are above the permitted standards.

Considering that real estate constitutes the principal base for the various components of the field, which makes controlling it and making perfect use of it one of the most difficult challenges facing those involved in the field of reconstruction, its rational and orderly consumption allows for the sustainable growth of the urban space. The city of Aris is one of the Algerian cities that knew a loose construction policy, which led to a gradual depletion of real estate as a result of the steep decline of the area and almost total consumption of the area, in addition to the legal nature of the real estate, which is controlled by the special character, this expansion collided with an area that could not be absorbed more than it is, and an urban fabric close to saturation, which calls for optimal exploitation of the vacant pockets within the urban fabric of the city. This city’s study included analyzing the legal nature of the real estate and counting the empty pockets to reach the most important results for the optimal exploitation of these pockets in light of the population increase the city is witnessing.

The main objective of this study is to establish a perspective orientation of urban growth in an arid region (Biskra and its neighboring oases) in south east Algeria by mobilizing the capacities of attractiveness. Taking into account climatic parameters (wind speed and temperatures) and physical parameters (land cover, slopes, and distance from roads), our approach is based on remote sensing techniques of satellite data classification and Geographic Information Systems for spatial analysis. By means of a multi-criteria analysis a decision support map of sites suitable for future urban dynamics was carried out. The results obtained show that 48% (or 71,782.25 ha) of the study area is located on land with very low sensitivity to urbanization. 9.45% at high sensitivity, 29.13% at medium sensitivity, while 13.41% at low sensitivity. The medium sensitivity zone occupies a considerable area estimated at 29.13% (a total of 43,577.58 ha). Spatially, this is reflected in uncontrolled urban sprawl to the detriment of oases and agricultural land, or land not suited to the requirements of climatic comfort in arid regions. This urbanization sensitivity map forms the basis of the prospective design of an urban model adapted and appropriate to the conditions of the oasis ecosystem through the integration of other climatic parameters.

Toensureconfidentialityandavoidhumainattacksagainstourdata, we exchange encryption and decryption keys. In our proposal scheme, we use the commutative properties of the product of circular matrices to create a com monencryptionkeybyapplyingtheprotocolof Diffie-Hellmanexchangethrough a classic channel. To raise the security level of our system we have introduced the sensibility of chaotic logistic maps in another exchange protocol which is the BB84throuth a quantum channal.

Due to the rapid growth of digital videos and the massive increase in video content, there is an urgent need to develop efficient automatic video content analysis mechanisms for different tasks, namely summarization, retrieval, and classification. In all these applications, one needs to identify shot boundary detection. This paper proposes a novel dual-stage approach for cut transition detection that can withstand certain illumination and motion effects. Firstly, we present a deep neural network model using the pre-trained model combined with long short-term memory LSTM network and the euclidean distance metric. Two parallel pre-trained models sharing the same weights extract the spatial features. Then, these features are fed to the LSTM and the euclidean distance metric to classify the frames into specific categories (similar or not similar). To train the model, we generated a new database containing 5000 frame pairs with two labels (similar, dissimilar) for training and 1000 frame pairs for testing from online videos. Secondly, we adopt the segment selection process to predict the shot boundaries. This preprocessing method can help improve the accuracy and speed of the VSBD algorithm. Then, cut transition detection based on the similarity model is conducted to identify the shot boundaries in the candidate segments. Experimental results on standard databases TRECVid 2001, 2007, and RAI show that the proposed approach achieves better detection rates over the state-of-the-art SBD methods in terms of the F1 score criterion.

The complications arising after the transplantation of conventional stents put atherosclerotic cardiovascular patients at high risk. Biodegradable poly-lactic acid (PLA) stents provide practical solutions for diseased vessels (atherosclerotic) and avoid the side complications of vessels and their incompatibility with permanent stents in the long term. PLA is a biodegradable and reliable material that is used for biodegradable stents designs to maintain natural mechanical behaviour in blood vessels. In this study, we suggest a new cross section ‘circular and elliptic’ that are proposed based on basic square shape cross section to study the mechanical behaviour of stents under pulsatile blood pressure in the blood vessels in order to choose the best shape to allow the biodegradability of Absorb stents with Poly-lactic Acid (PLA) material by numerical fatigue study. Three types of cross-sections stents struts have been analysed to compare their mechanical properties in terms of stress, strain, fatigue damage and life cycle. The numerical results obtained from the finite element analysis (FEA) method demonstrate that the elliptical and circular stents design has better efficiency in terms of stress and strain (16.66–33.33%) and fatigue damage (62.4–86.07%) compared to the square design.

Thiacloprid (THI) is a nicotinic receptor agonist widely used as pesticide in Algeria, however it is susceptible to accumulate in various fruits and vegetables and pouringdownstream into food platesandcontributesto the development of neurodegenerative diseases. Conversely, several natural compounds are provided with cytoprotective potential and, therefore, are able to act against the harmful effects of toxicants such as pesticides. This study focused on striatum (str) and hippocampus (hipp) mitochondrial toxicityassessment, evaluation of behavioral function and intrinsic apoptosis pathway in rats exposed to THI at low-dose (0.020 mg/kg) for 3 months. In addition, this study examined neuroprotective potential of bitter apricot kernel extract when administered concomitantly with THI at the dose of 50 mg/kg. In current study, assessment of mitochondrial permeability transition pore (mPTP) and swelling, evaluation of mitochondrial redox status, cholinergic function (Ach E) and apoptosis markers (Caspase 9 and 3, Bax and Bcl2, Cytochrome c and cytosolic calcium) were performedin both brainareas, besides behavioral and histopathological examination. The results showed an increase of lipid peroxidation in both of str and hippwith a values of 1,14 ± 0,04nmol/mg of proteins(pr)and 1,58 ± 0,09nmol/mg pr.respectively and a significant decrease in GSH(0,09 ± 0,01mmol/mg pr.in hipp and 0,08±0,01mmol/mg pr. in str), the results also showed a change in the activity of antioxidants enzymes SOD (16,37±1,09UI/mg pr.in hipp14,54±1,46UI/mg pr.in str) , CAT (0,010±0,01UI/mg pr.in hipp and 0,005±0,004UI/mg pr.in str), GPx (0,01± 0,001nmol/mg pr.in both hippand str) and GST (23,73±1,68UI/mg pr.in hipp and 17,56± 1,04UI/mg pr.in str), as well as an abrupt increase in mPTP opening with a value of (0,057±0,005 in str and 0,054±0,005 in hipp) , which leaded to mitochondrial swelling where the level o mitochondrial swelling was (0,016±0,002 in str and 0,106±0,003 in hipp), the swelling was associated also with a high releasing of Cyt-c with a values of (4,48 ± 1,26μg/mlin str and 5,32 ± 1,08 μg/mlin hipp ) and Ca++( 2,26±0,06mmol/lin str and 2,32±0,07mmol/lin hipp) into the cytosol, the results also showed a significant decreasing of Bcl2 (16,4 ± 1,86ng/mg prin str and 14,8± 0,82ng/mg prin hipp), in the other hand the rates of caspase-9 were (278±14mAbs/mg pr.)in str and 212 ±24mAbs/mg pr.in hipp), caspase3 (184± 16mAbs/mg pr.)in str and 250 ±14mAbs/mg pr.in hipp), and BAX (0,926ng/mg prin str and 1,189ng/mg prin hipp) were increased. The results of this study revealed also a decrease of memorization processes and learning abilities, at the same time a decrease in Ach E activity (14,02± 0,78 nmol/min/mg pr.in str and 22,35± 1,77 nmol/min/mg pr.in hipp) was recorded. Inversely, bitter apricot kernels extract showed higher cytoprotective potential against THI neurotoxicity, since mitochondrial redox homeostasis and membrane integrity were recovered, cognitive impairment and brain tissue damage were also prevented. In conclusion, THI induced mitochondrial disorders, triggered apoptosis signaling pathway and impaired cognitive functions whichwere prevented by bitter apricot kernels extract when associated with this pesticide.

Direct steam generation (DSG) in parabolic trough solar collectors is a feasible option for economic improvement in solar thermal power generation. Three-dimensional Eulerian two-fluid simulations are performed under OpenFOAM to study the turbulent flow in the evaporation section of the parabolic trough receiver and investigate the phase change, and pressure drop of water as a heat transfer fluid. First, the model's validity has been tested by comparing the numerical results of a laboratory scale boiler with the available correlations and semi-correlations of boiling flows from the literature. Simulations agreed well with Rouhani–Axelsson correlation for horizontal tubes, with a mean relative error of less than 7.1% for all studied cases. However, despite a mean relative error of less than 13.19% compared to the experimental data in the literature, the reported pressure drop factor remains valid; overprediction remains tolerable for most engineering applications. Second, the scaling effect on the mathematical model, from laboratory to commercial-scale configuration, was tested with experimental data of the DISS test loop in Platforma Solar de Almeria, Spain. The Monte Carlo Ray Tracing method under the Tonatiuh package allowed for obtaining the nonuniform heat flux distribution. Due to the large size of the evaporation section in the DISS loop (eight collectors), each collector is considered independently in the simulations. Thus, simulations follow each other, taking the numerical results of each collector output as input data in the next collector and so on until the last. The numerical results showed an excellent agreement for the void fraction with 3.53% against the Rouhani–Axelsson correlation. Frictional pressure losses are within a 17.06% error of the Friedel correlation, in the range of previous work in the literature, and the heat loss is less than 4.69% error versus experimental correlation.

We consider a system of transmission of the wave equation with Neumann feedback control that contains a distributed delay term and that acts on the exterior boundary. We prove under some assumptions that the solutions decay exponentially in an appropriate energy space. To establish this result, we introduce a suitable energy function and use multipliers technique method and compactness-uniqueness argument.

Due to the high degree of randomness in the microstructure of real closed-cell foams, many reported numerical models in the literature are not able to capture precisely the local morphological features found in solid foams geometry. This is still the main impediment that restricts the investigation of this novel material and motivates the development of a sophisticated 3D solid model, which describes properly the complex geometry of real closed-cell foams. In this regard, this paper presents an original approach to generate a realistic and accurate 3D computational model of irregular closed-cell foams with relative density control and detailed finite element analysis of their mechanical performance under quasi-static loading up to densification. The solid model is constructed based on spherical particles inflation simulation. It resembles the real foams in terms of local features such as cell walls irregularities and thickness variation. The modeling approach was successfully verified by comparing cell-morphological details of the generated models with those produced experimentally available in the literature and by the high-quality of obtained 3D printed models containing complex shapes and irregular cell wall thickness distribution. The evolution of spherical particles during the inflation process is analyzed based on finite element (FE) simulations. It was found that it can produce varying relative densities of foam due to the gradual decrease in the gap between the inflated particles, this makes the geometrical model of the foam suitable for studying the effect of local morphological characteristics on the mechanical performance of closed-cell foam material. To demonstrate that the compressive performance of the proposed closed-cell foam models can be controlled by relative density, 3D foam models were extracted from different inflation times and then subjected to quasi-static compression tests up to densification using the Abaqus software. The results confirm that the plateau stress can be expressed as a function of foam relative density, its accuracy is validated by comparing it to the closed-cell aluminum foam power law equation existing in the literature. The new design method offers suitable numerical models for AM technology, plenty of experimental works on closed-cell foam can be reduced for engineering applications.

Several difficulties and critical problems are facing the modern designers especially the unexpected damages. For such critical issues, the steel behavior’s investigation presents a significant point to predict fatigue life through avoiding sudden damage. An experimental study has been conducted to evaluate the AISI 1045 steel fatigue behavior using three specimens’ shapes: the first one is the conventional shape according to the ASTM E466-07 standard, the second one is performed in a notched shape, and the last specimen according to the pre-loading process. To complete the comparison among the three cases studied, a mandatory checking of the chemical compositions such as carbon content 0.45%, as well as the mechanical properties, have been investigated by preformed a tensile test in order to determine the maximum stress and the yield strength. The staircase method is employed to estimate and compare the endurance limit and its standard deviations for the three shapes. Moreover, and considered that the fatigue life expectancy of the AISI 1045 steel is a crucial step, the Stromeyer model has been proposed to predict the fatigue life which appears to be more effective, considering the average error for all cases compared to the experimental model.

The short circuit is among one of the most dangerous electrical faults in induction motors, which leads to serious implications on the motor operation and its performance. The present paper deals with the influence of the stator short circuit fault in its early stage in terms of performanceand service continuity of an electric vehicle (EV) using a dual induction motor’s structure piloted by Backstepping control. An equivalent induction motor model with turn-to-turn fault on one stator phase, without already assuming the temperature effect through an intrinsic model, is investigated. Afterward,its impacts on electric vehicle performance using simulation tests are presented anddiscussed.

The magnetohydrodynamic pump is an attractive solution, in particular for biomedical applications. In an MHD pump, an electromagnetic force is created by the applied magnetic field, which causes the fluid movement. The main advantage of the MHD pump is there are no mobile (mechanical) parts and it can place directly on veins. The present paper deals with the blood behaviour in the MHD micropump. A neodymium permanent magnet is used for applying a magnetic field to the channel in the MHD micropump. The numerical study examines the influence of the channel dimensions, the flux magnetic density and the electrode potentials on the blood velocity. This micropump can be easily controlled by a low voltage source. The numerical simulation analysis for the adopted model was implemented in order to verify the micropump operation. The magnetic and electrical fields have a strong influence on blood velocity in the MHD micropump. Finite element modelling software was used for this process. The second objective of this work is the possibility to exploit the properties of this pump in hemodialysis to pump blood and cleaning fluid.