University of Science and Technology Houari Boumediene
Recent publications
Changes in socio-economics, demography, politics, and climate in arid and semi-arid regions in recent decades have led to profound transformations in livestock practices, particularly in the management of local animal resources. The dromedary Camelus dromedarius has always played an important role in human life history in Algeria; it provides a substantial contribution in protein production such as milk and meat, and it is used as means of transportation by local populations. It is well-adapted to arid environments and has a satisfactory potential for food production that enables economic security to locals, especially in the context of climate change. This paper adds supplementary yet valuable information to the current knowledge on camel genetic diversity related to different management practices. Genetic and phenotypic variations and the underlying management practices are studied to understand differences between breeds, for a better resource management. The survey of 277 camel breeders across the Algerian desert revealed a genetic diversity in terms of breeds driven by four pastoral practices. According to coat colour and morphological aspect, the camel population “Tergui” corresponds to three breeds, namely Mahri with 53.13% of the population, Marouki (43.22%), and the single-ecotype Azerghaf (3.65%). Mahri is a mixture of Amelal and Abahou ecotypes that are being outnumbered by Marouki’s ecotypes (Atelagh and Alemlagh). This biodiversity is under real threat because of the behaviour of pastoral societies that pushes breeders to turn to breeds with a high market value. Several useful conservation methods, including the use of modern farming systems, could be positively used and/or improved, in order to protect the genetic variety and help breeders realize a good living out of rearing camels.
Five species of genus Asparagus are recognized in the flora of Algeria: A. acutifolius L., A. albus L., A. horridus L., A. officinalis L., and the endemic A. altissimus Munby. The chorology of each of these species is fairly well known. In this study, morphological variation and the anatomical features of the cladodes have been evaluated in respect to each taxonomic unit and ecogeographical distribution and suggest distinct adaptive strategies. Analysis have been performed on twenty-nine natural populations sampled along the east-west bioclimatic gradient of the Northern Algeria. Multivariate analysis based on the main diagnostic descriptors, underlines the interspecific differentiation particularly with respect to the stigma type bifid versus trifid, shape of flowers, color of berry, and the number of cladodes in a fascicle. For each species the anatomy of the cladodes is unique, unlike that of stems and roots. Interspecific differentiation was observed in the form of cross-sections of the cladode, thickness of the cuticle, shape of epidermal cells, number of vascular bundles and presence of raphides. Morphological and anatomical traits of the cladode constitute important interspecific criteria within the genus Asparagus.
This paper treats the problem of social navigation and human–robot interaction. In most previous works addressing this issue, the proxemia concept has been considered static with regards to the activity’s nature. Furthermore, the F-Formation type is not considered. The different activities of people can not be considered similarly. For example, the way to navigate socially without disturbing a group drinking coffee or discussing a poster is different, just like the interaction location when serving coffee or explaining a poster. The main contribution of this paper is to propose a dynamic proxemia modeling approach “DPMA” for social navigation and interaction. It is based on proxemia and spatial modeling, which allow the robot to navigate socially by considering the comfort of people, and to interact in appropriate interaction conditions. It considers the F-Formation type and the nature of the activity, additionally to the different social spaces and the navigation and interaction constraints. Then, it uses a social map to encode them. The performance and the efficiency DPMA are evaluated both in three simulation environments using the ROS Stage simulator and on a real robot used as a service robot in a mediation event example. Promising results are given in this paper.
In this paper, we present a branch-and-bound based algorithm to generate all non dominated points for a multiobjective integer programming problem with convex objective functions and linear constraints (MOICP). The principle is to solve a single objective program (P) defined from the original MOICP program with relaxed integrality constraints. Whenever an integer solution is found through the branching process, a node is created in the search tree for each criterion. That is, by adding a cutting plane that locally approximates the criterion, as to exclude a subset of dominated points. The nodes are traversed according to the depth-first strategy and the same process is repeated for the obtained programs as (P). Finally, as to illustrate the efficiency of the suggested algorithm, we present an experimental study, where we assess its efficiency using randomly generated quadratic multiobjective integer problems with linear constraints.
The Earth Air Heat Exchanger (EAHE) is a promising passive technique that utilises shallow geothermal energy to improve the thermal comfort in buildings. EAHE has the potential to minimize the amount of electrical energy used by traditional air conditioning systems. The aim of this research is to examine the thermal performance of the EAHE under continuous operation. A transient numerical model was developed using the implicit finite difference method. Afterwards, the thermal performance was evaluated by using the means of derating factor. In addition, an experimental setup is realised in Biskra University (Algeria) to take measurements during cooling period. According to numerical calculations, the high thermal performance of EAHE is dependant on high thermal conductivity of soil and low air velocity. The values of the derating factor in the studied cases ranged from 0% to 35% that can mislead the design of the EAHE if ignored. The experimental findings revealed that for 3.5 m/s of air velocity, the maximum air temperature drop can reach up 19 °C. It is noticed that the initial 33 m of the pipe can provide 91% of the whole reduction in air temperature. In extreme real cases, the maximum air temperature increasing does not exceed 0.85 °C during all 95 h. Consequently, ambient temperature decreases during night operation and then cools the heated subsoil and assists the soil to recover its cooling capacity.
Alfa grass is one of the most abundant and renewable natural fiber resources in North Africa. In this regard, this work aimed to valorize this plant by preparing a sandwich panel composed of Alfa fiber-based core and a hybrid polymer matrix composite (jute and metallic mesh) as skin. The mechanic properties of the parts (the core, skin and whole sandwich composite) were evaluated by bending, tensile and non-destructive tests. Thanks to Alfa fiber-based core, the resulting sandwich performance was higher compared to other bio-based ones such as cork-based sandwiches but had higher density. The hybridization of the jute improves the rigidity of the skin (about 65% of Young and flexural modulus, respectively) but decries the tensile strength by about 23%. The sandwich breaking was strongly influenced by the stacking sequence of the skin, the presence of metallic mesh at the interface core/skin led to delamination, which reduces the mechanical properties of the sandwich. Overall, this sandwich could find useful application as a non-structural component in building materials (separation or roofs panels).
Understanding atmospheric circulation is essential to study particle transport in the atmosphere. This applies to certain ions (chloride, sodium, calcium, sulfate, lead, and so on) as well as certain radio-elements (cesium, polonium, tritium, etc.…). The transfer factors are primarily controlled by atmospheric dispersion and diffusion. The spatial distribution and estimation of chloride deposits in precipitation are more than necessary for such use and quantification of recharge. The aim of this paper is to calculate the annual deposition of atmospheric chloride in the semi-arid area of Djelfa using a model derived from the perfect gas theory. This model, described as parsimonious, includes two basic parameters: rainfall and temperature. It is particularly useful in semi-arid areas with varying precipitation over time and space. Overall, this new numerical modeling approach emphasizes the importance of quantifying the distribution of chloride deposition in watersheds where data is frequently missing or scarce. Its implementation on site allowed the measurement of chloride mass deposition rates ranging from 1.52 to 31.70 g/m²/year with an average of 13.41 g/m²/year. Over the entire catchment area (1300 km²), the average annual deposit is around 13,500 tons/year.
Microemulsions (MEs) are homogeneous, optically clear and thermodynamically stable systems intended to increase the bioavaibility, solubility, and entrapment of drugs. In this study, a new system of oil-in-water MEs was formulated with Fusidic acid as a drug. MEs were composed of Isopropyl myristate, non-ionic surfactants tween 80, 1-propanol and water. The optimum weight ratios of components and MEs areas were determined by pseudoternary phase diagram. The prepared microemulsions were evaluated regarding their stability, pH, refractive index, conductivity, viscosity, particle size, zeta potential, surface tension and partition coefficient. These parameters suggested that the optimized MEs were stable and optically clear. This study reveals that the product can be used for ocular treatment.
The aim of this work is to provide a semantic scene synthesis from a single depth image. This is used in assistive aid systems for visually impaired and blind people that allows them to understand their surroundings by the touch sense. The fact that blind people use touch to recognize objects and rely on listening to replace sight motivated us to propose this work. First, the acquired depth image is segmented and each segment is classified in the context of assistive systems using a deep learning network. Second, inspired by the Braille system and the Japanese writing system Kanji, the obtained classes are coded with semantic labels. The scene is then synthesized using these labels and the extracted geometric features. Our system is able to predict more than 17 classes only by understanding the provided illustrative labels. For the remaining objects, their geometric features are transmitted. The labels and the geometric features are mapped on a synthesis area to be sensed by the touch sense. Experiments are conducted on noisy and incomplete data including acquired depth images of indoor scenes and public datasets. The obtained results are reported and discussed.
Hydrogel nanocomposites comprised of chitosan-grafted-hydrolyzed polyacrylamide as matrix and montmorillonite clay as nanofiller CTS-g-PAAm/MMT were synthesized in aqueous phase by using Triton X-100 surfactant as porogen agent with the aim to apply as adsorbents for the removal of Basic Red 46 (BR46) dye. The as-prepared ampholytic hydrogels, denoted as M/MMTx (x = 0, 2, 5, and 10 wt.% of clay loading), were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The nanohybrid hydrogels exhibited mostly exfoliated structure of the MMT layers and presented morphology that is more porous as compared to the virgin matrix. Also, the thermal stability was marginally affected by clay loading. Study on the swelling behavior showed remarkable water super-absorbing ability, salt-, and pH-sensitivity. The adsorption performances were evaluated by varying clay content, adsorbent dose, pH, initial dye concentration, contact time, and temperature. The results showed that the sorption rates were fast and more than 78% of adsorption capacities were achieved within nearly 30 min using 0.1 g L−1 sorbent dose in 200 mg L−1 of dye solution. The nonlinear kinetics and isotherm adsorption models fitted on the experimental data correlated well with pseudo-second-order kinetics and Langmuir models. Also, the intra-particle diffusion mechanism is not rate-limiting step and the adsorption was suggested to occur mainly via electrostatic interactions and hydrogen bonding. The maximum Langmuir adsorption capacities (qm) of the matrix and the optimized nanocomposite M/MMT2 were found to be 1553 and 1813 mg g−1, respectively. Thermodynamic parameters revealed that sorption process was endothermic and spontaneous. Moreover, effective regeneration was obtained in four adsorption–desorption cycles and about 92% of the adsorbed dye was released from hydrogels. Results obtained from this study suggest that the prepared hydrogel nanocomposites could be promising adsorbents for removing cationic dyes from polluted water.
Envenomation by Cerastes cerastes often results in local dermonecrotic lesions. While immunotherapy is effective in reversing systemic symptoms, this strategy remains deficient in counteracting the extended dermonecrosis induced from the bite site. In this study, the therapeutic effect of pharmacological drugs on the dermonecrotic activity of the venom was investigated. Venom administration caused a marked dermonecrotic lesion with increased levels of oxidative stress biomarkers (MPO, EPO, NO, H2O2, MDA, protein carbonyl, and thiol levels). Antioxidant capacity was decreased, as evidenced by reduced catalase, glutathione, and selenium levels. Histopathological analysis of skin biopsies revealed necrotic lesions accompanied by hemorrhage and epidermis thickening. The efficiency of cyproheptadine (C), dexamethasone (D), and tetracycline (T), as a monotherapy or in association, were evaluated on the dermonecrotic activity of the venom. Most of the treatments (CD, CT, DT, and CDT) largely reduced tissue necrosis to, respectively, 84.29, 87.83, 83.77, and 82.71% and significantly decreased MPO and EPO activities and NO, H2O2, MDA, and protein carbonyl levels in skin tissue homogenates. CT and CDT associations significantly increased the antioxidant status as indicated by enhanced catalase, glutathione, and selenium levels. The second challenge of the pharmacological associations was more effective in improving the oxidative/antioxidative balance. Skin tissue sections from treated animals with CT or CDT revealed tissue structure close to that observed in control animals. Therefore, the synergistic action of all tested drugs on the major pathways of inflammation (phospholipases A2, metalloproteinases, and histamine) seems to be efficient to neutralize the necrotic activity of the venom.
In the present work, a multicomponent protocol has been described for the synthesis of various benzylpyrazolyl-coumarin 5a-i structures, involving the reaction of 4-hydroxycoumarin, ethyl acetoacetate, hydrazine hydrate, and aldehydes, using an ethanol-water (1:1) mixture as the reaction medium and sodium dodecylbenzenesulfonate (SDBS) as the catalyst. This new approach has advantages such as short reaction time, recovery of the catalysts after the catalytic reaction and their reuse without loss of activity, as well as the lightening of the process. The structures of the obtained benzylpyrazolylcoumarins were determined and confirmed by melting point, ¹H NMR and ¹³C NMR. The determination of antioxidant activity of the obtained benzylpyrazolylcoumarin 5a-i derivatives was studied using the DPPH scavenging assay. Molecular modeling studies using DFT (density function theory) calculations showed that there are six tautomeric structures A to F in which structure C is more stable than the others.
Amorphous layer up to 20 μm thick were obtained from bulk diffusion couples between pure copper and Zircaloy4 after isothermal treatment at 900 ∘C and slow cooling to room temperature. It has been shown that the Cu-rich liquid exhibit a low mobility and high viscosity, and that the asymetrical diffusion behavior of Zr and Cu together with the interfacial reaction rate constrain the liquid layer and allows to avoid nucleation of intermetallic compounds up to 45 minutes holding time. The Cu-rich liquid layer forming at the holding temperature is stable and grows until another liquid, richer in Zr, appears.
Northwestern Algeria is located where the Saharan Atlas borders the Saharan Platform along the South Atlas Front. The origin of the South Atlas Front is controversial, thus a detailed gravity and magnetic analysis constrained by seismic reflection profiles and well data were conducted to determine the structural configuration of this region. A residual gravity anomaly map created using upward continuation and a reduced to the pole magnetic anomaly map indicated a series of northwest-trending maxima anomalies parallel to the Atlassic orogeny folds and faults and east-trending maxima within the Benoud foreland basin. These maxima mostly coincide with Paleozoic basement uplifts based on seismic reflection profiles. Depth analyses based on upward continuation, and two-dimensional forward modeling of the gravity and magnetic data indicated that the source of the maxima are mainly 5 km in depth with the magnetic sources being approximately 0.5 km deeper than the gravity sources. The gravity and magnetic models indicate that the source bodies are steep-sided and coincide with interpreted faults from the seismic reflection profiles. The maxima anomalies are mainly caused by basement uplifts instead of variations in density and/or magnetic susceptibility in the Paleozoic or older basement lithologies. The South Atlas Front and the Saharan Atlas on the central and eastern portions of Algeria is governed by a thin-skinned tectonics style involving the Mesozoic-Cenozoic sedimentary cover. While the western part was probably controlled by a mixed thin- and thick-skinned tectonic style with the reactivation of deeply rooted Triassic and Jurassic faults during Tertiary compressive events in the interpreted Paleozoic basement. Our gravity and magnetic models illustrate a crustal architecture model of the Paleozoic basement which is consistent with a north-dipping basement normal fault between less deformed Saharan Platform than the more deformed Atlassic domain. Such a crustal model aids in determining the nature of the Atlassic orogeny as geological and geophysical studies have been determining the variations of structural styles along its entire length.
Hypersaline ecosystems host a particular microbiota, which can be specifically recruited by halophytes. In order to broaden our knowledge of hypersaline ecosystems, an in natura study was conducted on the microbiota associated with the halophyte Halocnemum strobilaceum from alkaline-saline arid soil in Algeria. We collected and identified a total of 414 strains isolated from root tissues (RT), root-adhering soil (RAS), non-adhering rhizospheric soil (NARS) and bulk soil (BS) using different NaCl concentrations. Our data showed that halophilic and halotolerant bacterial isolates in BS and the rhizosphere belonged to 32 genera distributed in Proteobacteria (49%), Firmicutes (36%), Actinobacteria (14%) and Bacteroidetes (1%). Bacterial population size and species diversity were greatly increased in the rhizosphere (factor 100). The reservoir of diversity in BS was dominated by the genera Bacillus and Halomonas. Bacillus/Halomonas ratio decreased with the proximity to the roots from 2.2 in BS to 0.3 at the root surface. Salt screening of the strains showed that species belonging to nine genera were able to grow up to 5.1 M NaCl. Thus, we found that H. strobilaceum exerted a strong effect on the diversity of the recruited microbiota with an affinity strongly attributed to the genus Halomonas.
This work presents laboratory experiments on effects of submerged obstacles on tsunami-like solitary wave and its run-up. This study was carried out for the breaking and non-breaking solitary waves on 1:19.85 uniform slope which contains a submerged obstacle. New laboratory experiments are performed, in medium-size wave tank, to describe the mitigation of tsunami amplitude and run-up under the effect of law-crested structures porosity. Four different obstacle porosities were used. To vary the obstacle porosity, we used gravel with different diameters, namely 3–8 mm, 8–15 mm, 15–25 mm and an obstacle perfectly impermeable. The results we obtained consist in the variation of the maximum run-up height value according to the wave height, and this for the four different porosities mentioned above, as well as the effect of this porosity on the shape of the wave downstream of the obstacle.
The present work aims to study evolutions of the metallurgical structure and the interfacial interactions in the SS-304L/Zy-4 dissimilar junction during isothermal holding at high temperature. The obtained interfaces were characterized by the combination of scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), electron probe micro-analyzer techniques (EPMA), Vickers microhardness (HV), and nanoindentation tests. The isothermal treatment at high temperature allowed the formation of both two layers at the reaction zone and a diffusion zone, on the Zircaloy (Zy-4) and the SS-304L sides, respectively. The layers observed on the Zircaloy side consist ε-Zr(Fe, Cr)2 and Zr2(Fe, Ni) intermetallic compounds (IMCs). Those observed on the SS-304L side consist of the α-(Fe, Cr) single-phase and another γ-(Fe, Cr, Ni) + α-(Fe, Cr) mixed part. According to values of microhardness (HV), nanoindentation hardness (H), and elastic modulus (E) obtained from the microhardness and nanoindentation tests, the ε-Zr(Fe, Cr)2 is considered to be extremely hard and brittle; however, Zr2(Fe, Ni) and α-(Fe, Cr) are moderately ductile.
In this paper, a speech enhancement method based on correlation canceling approach associated with the Log- minimum mean-square-error estimator is presented. Unlike the conventional statistical-model methods based on the nonlinear estimation of the enhanced speech signal, such as Maximum-Likelihood estimator (ML), Maximum A Posteriori (MAP) estimator, Minimum Mean Square Error (MMSE) estimator and log MMSE estimator, in the proposed hybrid method (CC/Log-MMSE), the nonlinear estimation is transformed into a linear estimation by exploiting the orthogonal projection of clean signal into the noisy signal. Thus, the enhanced signal represents the best “copy,” or estimate, of clean signal that can be made on the basis of the noisy signal vector. This is also seen as a canceling of the component of the noisy vector residing in the noise subspace, which therefore leads to improve the intelligibility of the enhanced signal. Extensive simulations are carried out using speech files corrupted by different noises available in the NOIZEUS corpus, show that the proposed hybrid method CC/Log-MMSE consistently outperforms the baseline methods of speech enhancement at different levels of SNR in terms of objective and subjective measures, spectrogram analysis and the overall SNR improvement.
In this paper, we construct an analytical study of the epidemic pine wilt disease model in a Caputo–Fabrizio type fractional order; the basic properties of the fractional differential equation and the model are presented; we give the basic properties of the model. Applying the homotopy analysis transform method to obtain numerical solutions to the model, the numerical result represented in graphs is presented.
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4,856 members
Samir Boukhenous
  • Department of Instrumentation and Control
Ladjici Ahmed Amine
  • Department of Electrical Engineering
Tarek Boutkedjirt
  • Faculty of Physics
Fatah Cherifi
  • Department of Cellular and Molecular Biology
BP 32 EL ALIA, 16111, Bab Ezzouar, Algiers, Algeria
Head of institution
University of Sciences and Technology Houari Boumediene
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