Epidermal anatomic characterization of spontaneous plants belonging to Poaceae, Cistaceae and Boraginaceae families in Algerian northern sahara

Microscopic examination of the epidermis of wild plants contained in the feces of the dromedary and ruminants is one of the methods for studying the animal diet. This work is a step to elaborate a reference catalog of epidermis to determinate the diet of camel and ruminants in the Saharan rang land situated in Algerian northern Sahara. In this paper, we described the most important epidermal anatomical characteristics of spontaneous perennial plants and ephemeral (08 species and 03families) grazed on Saharan rang land, by using an binocular light microscope. From the results, we propose an identification key to these 08 species from their epidermal characters

Hypovitaminosis D and prevalent asymptomatic vertebral fractures in Moroccan postmenopausal women

BACKGROUND: Hypovitaminosis D is associated to accentuated bone loss. However, association between osteoporotic vertebral fractures (VFs) and vitamin D status has not been clearly established. OBJECTIVE: To determine serum vitamin D status and to assess the association of vitamin D status with bone mineral density (BMD) and asymptomatic VFs prevalence using vertebral fracture assessment (VFA) in a cohort of Moroccan menopausal women. METHODS: from June to September 2010, 178 menopausal women 50 years old and over were enrolled in this cross-sectional study. The mean ± SD (range) age, weight, height and BMI were 58.8 ± 8.2 (50 to 79) years, 73.2 ± 13.8 (35 to 119) Kgs, 1.56 ± 0.06 (1.43 – 1.79) m and 29.8 ± 5.9 (17.5 – 49.8) kg/m(2), respectively. VFA images and scans of the lumbar spine and proximal femur were obtained using a GE Healthcare Lunar Prodigy densitometer. VFs were defined using a combination of Genant semiquantitative approach and morphometry. Serum levels of 25-hydroxyvitamin D (25(OH)D) were measured. RESULTS: Among the 178 women, 45 (25.2%) had densitometric osteoporosis, and on VFA, VFs (grade 2 or 3) were detected in 20.2% while grade 1 were identified in 33.1%. The mean values of serum levels of 25(OH)D were 15.8 ± 11.6 ng/ml (range: 3.0 – 49.1) with 152 patients (85.3%) having levels <30 ng/ml (insufficiency) and 92 (51.6%) <10 ng/ml (deficiency). Stepwise regression analysis showed that presence of VFs was independently related to age, 25(OH)D and densitometric osteoporosis. CONCLUSION: our study shows that advanced age, hypovitaminosis D and osteoporosis are independent risk factors for asymptomatic VFs in Moroccan postmenopausal women

Résonances photoniques et propriétés des microstructures en champ proche: Application au cas de polymères conducteurs

L’optique de la résonance plasmon de surface a été connue depuis longtemps. Dans la configuration de Kretschmann, le couplage optique d’une onde incidente aux oscillations collectives d’électrons le long d’une interface entre un métal et un diélectrique est gouverné par l’épaisseur de la couche métallique. Dans ce présent travail, nous discutons de l’utilisation d’une structure bi-métallique pour générer les plasmons-polaritons de surface (SPPs). Dans une première étape, nous étudions l’influence de l’épaisseur de l’Ag et de l’Au séparément sur la résonance du plasmon-polariton de surface. Dans une seconde étape, nous présentons les résultats analytiques de la réflexion lumineuse (en fonction de l’angle d’incidence) pour deux dispositions Ag-Au et Au-Ag qui sont excitées par une onde électromagnétique dans la bande visible (λ=410nm- 699nm). Pour ces métaux, nous avons pris en particulier une dépendance en fréquence sur leurs permittivités diélectriques εAg(λ) et εAu(λ) et qui sont tabulées dans la référence de Johnson-Christy. Nous trouvons finalement des caractéristiques de base pour les résonances des plasmons-polaritons de surface. Nous soulignons un résultat important pour produire le phénomène de couplage où la résonance plasmon de surface devient indépendante de la couche métallique dAg pour la disposition Au-Ag. La résonance angulaire du plasmon est seulement décalée vers l’angle de la réflexion total ; i.e., angle critique. Cependant, nous expliquons cet effet que la structure bi-métallique peut piéger les plasmons( SPPs) avec un taux optimal dans la réflexion lumineuse. Pour le piège plasmonique obtenu par la disposition Au-Ag en contact avec un milieu diélectrique (supposé l’air ambiant) qui est irradiée à une longueur d’onde 427nm, il est imposé une épaisseur dAu+dAg= 60nm. Dans différentes conditions fixées de l’épaisseur dAg dans la bande 44nm-59 .9nm, au-delà d’un seuil de valeur de 44nm ( pour dAg), le creux dans la réflectivité n’est pas lié à l’épaisseur dAg. Une caractéristique identique est vérifiée avec une longueurs d’onde λ=410 ,492,545nm où le creux est plus étroit et la résonance angulaire n’est pas fortement décalée. Lorsque la longueur d’onde est décalée vers le bleu, le contrôle du piège plasmonique impose la valeur seuil dAg qui doit être plus importante

Wind energy conversion system based on DFIG using three-phase AC-AC matrix converter

Due to the development of power electronics technology, the use of a new generation of power converter AC-AC matrix converters has received special attention, which provides direct power converter AC-AC, bidirectional power flow, near-sinusoidal input, and output waveforms. The performance analysis of a variable-speed wind turbine based on a doubly fed induction generator and connected to the main grid through a three-phase matrix converter is presented in this paper. Additionally, this paper proposes the utilization of a space vector modulation approach in the three-phase matrix converter. Other benefits of the space vector modulation approach include lower total harmonic distortion of output voltage and lower switching loss. The simulation analysis of the proposed power conversion system using MATLAB/Simulink/SimPowerSystems toolbox R2021a is presented in this paper

Removal of chromium (VI) ions from polluted water using kaolinite-supported Fe/Al oxide(hydroxide) composite nanoadsorbents

Hexavalent chromium (Cr (VI)) contamination of surface and groundwater has become a major environmental concern owing to the diverse applications of Cr(VI)) in several industries. In the current study kaolinite-supported and size-controlled Fe/Al oxide(oxyhydroxide) nanocomposites (Kaolinite@Fe/Al nanocomposites) were synthesized for efficient removal of Cr(VI) from aqueous solution. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis of the nanocomposites revealed that the nanocomposites were uniformly dispersed, with an average particle size of ~ 25 nm. Batch adsorption studies were carried out to study the effect of (Kaolinite@Fe/Al nanocomposites) on the removal of chromium (VI) from 100 mg/L Cr(VI) contaminated water over a wide pH range (3–10) at various adsorbent dosages. The result demonstrated that the nanocomposites’ adsorption efficiency increased with increasing adsorbent dosage. When the Kaolinite@Fe/Al nanocomposites dosage was increased from 1.0 to 3.0 g/L, the Cr(VI) removal percentage increased from 65.4 % to ∼99.0 %. This is due to the greater surface area and availability of more adsorption sites at higher dosages of the adsorbent. There was a significant removal of Cr(VI) in the pH range 3–6 reaching up to 99.0% Cr(VI) removal, however, removal efficiency decreased drastically beyond pH 6. Chromium (VI) exists as CrO4 2−, HCrO4 − and Cr2O7 2− oxyanionic species while the surface of the adsorbent becomes highly protonated, owing to the variable surface charge imparted by Al/Fe oxides/hydroxides favouring remarkable uptake of Cr(VI) in the anionic form. The experimental data fitted Langmuir adsorption model well with a maximum adsorption capacity of 70.71 mg/g. The results of the study demonstrate that Kaolinite@Fe/Al nanocomposites may have a promising potential for remediation of Cr(VI) contaminated wastewater and industrial effluents.The Water Research Commission (WRC) grant for externally funded Postdoctoral Fellowship and the National Research Foundation (NRF) of South Africa.http://www.aidic.it/cetam2023Chemical Engineerin

MOOA-CSF: A Multi-Objective Optimization Approach for Cloud Services Finding

Cloud computing performance optimization is the process of increasing the performance of cloud services at minimum cost, based on various features. In this paper, we present a new approach called MOOA-CSF (Multi-Objective Optimization Approach for Cloud Services Finding), which uses supervised learning and multi-criteria decision techniques to optimize price and performance in cloud computing. Our system uses an artificial neural network (ANN) to classify a set of cloud services. The inputs of the ANN are service features, and the classification results are three classes of cloud services: one that is favorable to the client, one that is favorable to the system, and one that is common between the client and system classes. The ELECTRE (ÉLimination Et Choix Traduisant la REalité) method is used to order the services of the three classes. We modified the genetic algorithm (GA) to make it adaptive to our system. Thus, the result of the GA is a hybrid cloud service that theoretically exists, but practically does not. To this end, we use similarity tests to calculate the level of similarity between the hybrid service and the other benefits in both classes. MOOA-CSF performance is evaluated using different scenarios. Simulation results prove the efficiency of our approach.

Desorption kinetics of polycyclic aromatic hydrocarbons (PAHs) from contaminated soil and the effect of biosurfactant supplementation on the rapidly desorbing fractions

There are often two phases in the desorption of polycyclic aromatic hydrocarbons (PAHs): an initial phase of rapid desorption and a subsequent phase of much slower release. By assessing the rapidly desorbing fraction of PAHs, a direct measure of the microbially degradable component of PAH contamination can be obtained and achievable bioremediation performances can be predicted. In this study, microbial biosurfactant produced by a Pseudomonas aeruginosa strain, identified as a lipopeptide by attenuated total reflectance Fourier transform infrared spectroscopy, was investigated for its efficacy in enhancing PAH desorption and mobilization in a spiked soil system. The desorption of pyrene and phenanthrene from the artificially spiked soil was enhanced 3.5 4.0 times at 700 mg L ¡1 lipopeptide amendment than at 150 mg L ¡1 amendment or in the unamended soil. The amount desorbed was generally in direct proportion to the amount of lipopeptide present. Mathematical modelling using a first-order two-compartment model was applied to simulate the process of desorption from the soil in the presence of different concentrations of lipopeptide and to predict the effect of the biosurfactant on the rapidly desorbing fraction. With the increase of supplementation of lipopeptide from 150 to 700 mg L ¡1, the rapidly desorbing fraction, which is generally considered to be the bioavailable fraction, increased from 18% to 73% and from 6% to 51% for phenanthrene and pyrene, respectively. This shows the potential application of the biosurfactant in increasing the bioavailable fraction and enhancing the bioremediation of PAH contaminated media.National Research Foundation (NRF) of South Africa through the Focus Areas Programme [grant number CPR20110603000019146] ; the Incentive Funding for Rated Researchers [grant number IFR2010042900080].http://www.tandfonline.com/loi/tbeq20hb2016Chemical Engineerin

Adsorption of As (III) from contaminated water on activated carbon-supported nanoscale zero-valent iron particles

Arsenic (As) contamination is a major concern due to its toxicity and tendency to accumulate and bio-magnify within the food chain, causing wider damage to the ecosystem. In the current study, activated carbon-supported nanoscale zerovalent iron (AC-nZVI) particles, were produced using chemical reduction of ferric chloride hexahydrate in the presence of activated carbon as a scaffold to avoid agglomeration and improve their dispersity. Detailed transmission electron microscopy (TEM), and scanning electron microscopy (SEM) characterization of the as-synthesized nanoparticles showed monodispersed nanoparticles of approximate size 45 ±10 nm. Their potential application for removal of As(III) from contaminated water was investigated in batch adsorption experiments at various adsorbent dosages and pH values. The results of the study demonstrated that AC-nZVI particles exhibited 82.5% removal of As (III) ions (initial concentration 100 mg/L) at an adsorbent dosage of 2 g/L. The adsorption performance increased with increasing adsorbent dosage and removed 99% As(III) at an adsorbent dosage of 5g/L. The Langmuir and Freundlich adsorption models were fitted to the experimental data, and it was found that the Langmuir isotherm fitted the data better than the Freundlich isotherm with a maximum adsorption capacity of 27.83 mg/g of adsorbent. In the current study As(III) exists predominately as uncharged species H3AsO30 under the designed pH range of 4-8, therefore the effects of solution pH on As (III) adsorption were hardly observed. The results of the study demonstrated that activated carbon-supported zerovalent iron particles can have tremendous potential application for the effective removal of As(III) from industrial wastewaters.http://www.aidic.it/cetam2023Chemical Engineerin

Copper Nanoparticle Doped Reduced Graphene Oxide (CuNP@rGO) Coated Poplar Wood for Solar-driven Interfacial Desalination of Saline Water

Global freshwater scarcity is one of the most pressing problems of the modern society. Solar driven interfacial desalination technology, which concentrates heat at the air-water interface and decreases thermal losses has gained an increasing attention owing to its high photothermal conversion efficiency and transformative environmental applications. However, there are still challenges of producing efficient and scalable photothermal materials with high evaporation rate, photothermal conversion efficiency and low cost. Graphene and its derivatives are ideal photothermal materials owing to their stability, excellent thermal and electrical conductivity, efficient broadband light absorption potential, lightweight and low cost. Conversion of graphene to reduced graphene oxide /plasmonic hybrid nanocomposites increases its performance and photothermal conversion efficiency. In the currents study copper nanoparticle doped reduced graphene oxide (CuNP@rGO) layered 3D poplar wood based interfacial desalination system was setup by depositing CuNP@rGO photothermal layer on porous hydrophilic poplar wood substrate and used for interfacial desalination of hypersaline water. The photothermal material displayed strong broadband solar absorption of ~95%, high evaporation rate of 1.39 kg.m-2.h-1, corresponding to photothermal conversion efficiency of ~96%, under 1-Sun solar irradiation, demonstrating the high energy efficiency and water generation potential. The results of the study demonstrated promising potential of the cost effective, environmentally sound, and scalable photothermal material for large scale real world saline water desalination and brackish water purification applications

Improvement of biosurfactant production by microbial strains through supplementation of hydrophobic substrates

Biosurfactants are amphiphilic tensioactive natural products that are capable of lowering the surface and interfacial tensions of the growth medium. Efficient biosurfactants are characterized by their ability to enhance the aqueous solubility of hydrophobic compounds and to emulsify hydrocarbons in aqueous medium. Improvement in the fermentation technology, strain selection and use of cheaper and renewable substrates have a vital role in enhancing the production processes of biosurfactant industries. However, large scale production of biosurfactants has not reached a satisfactory economical level due to their low yields. Several studies have reported significant effect of carbon sources on the productivity of biosurfactants by different strains. In the current study medium composition optimization approach was investigated for optimal biosurfactant production using a combination of hydrophobic and hydrophilic carbon sources by Bacillus subtillis CN2 strain, previously isolated from hydrocarbon contaminated soil. The study demonstrated that both quantity and type of carbon sources prompted a significant difference in the amount and activity of the biosurfactant produced. The hydrophobic carbon sources were found to be superior to hydrophilic ones in promoting biosurfactants production and surface activity superiority. The strain produced 10-fold more biosurfactant when growing on oil than when grown on glycerol and significantly higher surface activity as determined from the emulsification index. In addition to using the hydrophobic substrate sunflower oil as a sole substrate, addition of sunflower oil (5%, wt/v) in to the growth medium after depletion of hydrophilic substrate (glycerol) stimulated the production of biosurfactant by more than 200%. Both the type and concentration of the carbon source were shown to be essential determinants of biosurfactant yield and physicochemical properties. The result of our study showed that the presence of optimal hydrophobic substrates in the growth medium triggered release of more biosurfactant through their inductive effect, which shows a promising potential of the approach for large scale viable biosurfactant production.The Claude Leon Foundation Postdoctoral Fellowship Program and the National Research Foundation (NRF) of South Africa through the Incentive Funding for Rated Researchers.https://www.cetjournal.itpm2021Chemical Engineerin