Nonlinear adaptive sliding mode control of a powertrain supplying fuel cell hybrid vehicle

International audienceThis paper presents an adaptive sliding mode based switching scheme for controlling DC-DC hybrid powertrain for propulsion of a Fuel Cell / Supercapacitor hybrid vehicle. After modeling the powertrain, a new approach to determine a nonlinear sliding surface ensuring stability of the DC/DC Boost converter is discussed. This was achieved without introducing the equivalent control aspect after transforming the instantaneous model of the Boost in a suitable form. The presented technique is also applied for trajectories tracking in the entire powertrain, which includes a dc/dc Boost converter associated to Fuel Cell stack and another Bidirectionnel dc/dc converter associated to the supercapacitor bank, which are both working in parallel to provide electricity propelling the vehicle. The control scheme is tested with driving cycle example through simulation

Ocean Wave Converters: State of the Art and Current Status

International audienceSolutions to today energy challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse energy resource plan. An extremely abundant and promising source of energy exists in oceans. Ocean energy exists in many forms. Among these forms, significant opportunities and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the wave motions and converting them into electrical energy. Regarding this emerging and promising area of research, this paper presents ocean wave energy fundamentals and then reviews the fundamental concepts and the main projects around the world. It also reports issues regarding electrical generator topologies associated to wave energy converters

A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular Waves

International audienceIn last decades, renewable energy resources are considered as an alternative energy resource to the world's excessive energy demand. An extremely abundant and promising source of energy exists in oceans. Currently, there are several wave energy converters to harness this energy. Some of them, as in tidal applications, use the Doubly-fed induction generator. This paper deals then with a predictive power control of this generator based Wave Energy Converter under irregular wave climate which is modeled as time series elevation from using Bretschneider spectra. In the proposed control approach, the predicted output power was calculated using a linearized state-space model. The DFIG-based WEC power tracking performances further illustrates the dynamic features of the proposed predictive power control approach

Optimization of process conditions to improve copper adsorption capacity of raw and treated Algerian bentonite: Characterization, kinetics and equilibrium study

249-261Raw bentonite (RB) locally available in Mostaganem (Algeria) deposit has been treated in the presence of NaOH (B-NaOH), MgCl2 (B-MgCl2) and H2SO4 (B-H2SO4) to improve its adsorption ability for the removal of copper ions from aqueous solutions. Characterization of all adsorbents supported montmorillonite, illite and kaolinite as major clay minerals identified for the raw and treated bentonites and proved the aluminosilicate structure of the clays. In synthetic solutions, the adsorption equilibrium of copper onto RB, B-MgCl2 and B-H2SO4 is reached in 30 min. while, equilibrium is reached after 4 hours when using B-NaOH. The adsorption kinetics are well described by the pseudo-second-order model. The adsorption of copper is pH-dependent. The Langmuir, Freundlich and Dubinin-Radushkevich isotherms indicate a suitable fit between the experimental data and models. The corresponding parameters indicate that the sorption mechanism might be physical in nature. The maximum adsorption capacities of Langmuir that are obtained are in the following order 25.1 mg/g (RB) < 28.03 mg/g (B-H2SO4) < 39.89 mg/g (B-MgCl2) < 72.80 mg/g (B-NaOH). The removal efficiency of copper in industrial wastewater was 45.75 %, 55.22 %, 63.27 % and 70.39 % using RB, B-MgCl2, B-H2SO4 and B-NaOH, respectively. The B-NaOH exhibit a higher adsorption capacity of copper with the other tested bentonites

Consensus Level and Knowledge of Spontaneous Medicinal Plants Used in Algerian Central Steppe Region (Djelfa)

Ethnobotanical studies gather pure information that can be used to support scientific research. Traditional remedies are considered as an alternative tool to chemical treatments in health care. This study aims to investigate the knowledge of spontaneous medicinal plant used by healers and elderly people. Moreover, it focuses on consensus level estimation of used medicinal plants. An exhaustive survey was carried out in the region of Djelfa in Algeria. The information was gathered from 43 informants who responded to structured questionnaire. Survey data were quantitatively characterized by five indices, namely; relative frequency citation, medicinal use-value, family use-value, informant consensus factor and fidelity level. In the current study, 51 species belonging to 28 botanical families were recorded and 185 uses and 58 diseases were described as well. Most recipes used a single species; however, some preparations were used as a species mixture. This specific preparation is called "Djor yebrir" and it was used as a curative treatment. The most represented families were the Asteraceae, Lamiaceae, Cupressaceae and Poaceae. The most cited species were Artemisia campestris L., Juniperus phoeniceae L., Teucrium polium L., Marrubium deserti (Noë) Coss., Artemisia herba alba Asso., Ruta montana (L.) L. and Saccocalyx satureioides Coss. et Durieu. These species were mentioned to treat mainly digestive system diseases and signs and ill-defined morbid states which showed the highest consensus level. This study reveals that traditional remedies are still used in this region. This information showed the abundance of medicinal plants and the ethnobotanical knowledge in the studied region which need to be preserved, so phytochemical and biological screenings are more than needed

Consensus Level and Knowledge of Spontaneous Medicinal Plants Used in Algerian Central Steppe Region (Djelfa)

Ethnobotanical studies gather pure information that can be used to support scientific research. Traditional remedies are considered as an alternative tool to chemical treatments in health care. This study aims to investigate the knowledge of spontaneous medicinal plant used by healers and elderly people. Moreover, it focuses on consensus level estimation of used medicinal plants. An exhaustive survey was carried out in the region of Djelfa in Algeria. The information was gathered from 43 informants who responded to structured questionnaire. Survey data were quantitatively characterized by five indices, namely; relative frequency citation, medicinal use-value, family use-value, informant consensus factor and fidelity level. In the current study, 51 species belonging to 28 botanical families were recorded and 185 uses and 58 diseases were described as well. Most recipes used a single species; however, some preparations were used as a species mixture. This specific preparation is called "Djor yebrir" and it was used as a curative treatment. The most represented families were the Asteraceae, Lamiaceae, Cupressaceae and Poaceae. The most cited species were Artemisia campestris L., Juniperus phoeniceae L., Teucrium polium L., Marrubium deserti (Noë) Coss., Artemisia herba alba Asso., Ruta montana (L.) L. and Saccocalyx satureioides Coss. et Durieu. These species were mentioned to treat mainly digestive system diseases and signs and ill-defined morbid states which showed the highest consensus level. This study reveals that traditional remedies are still used in this region. This information showed the abundance of medicinal plants and the ethnobotanical knowledge in the studied region which need to be preserved, so phytochemical and biological screenings are more than needed

Teneur en iode et qualité des sels alimentaires commercialisés dans la région de Djelfa [Iodine content and quality of dietary salts marketed in the Djelfa region]

Introduction. L’Algérie, à l’instar des autres pays, a adhéré au programme universel d’iodation de sel initié par l’Organisation Mondiale de la Santé (OMS) dans le but d’éliminer les troubles dus à la carence en iode (TCI). Objectif. L’objectif de cette étude est d’évaluer la teneur en iode des sels alimentaires commercialisés dans une région steppique centrale de l’Algérie et d’estimer le degré de respect du programme d’iodation du sel. Matériel et méthodes. Quarante cinq échantillons de sel alimentaires commercialisés dans la localité de Djelfa ont été analysés. Ces échantillons proviennent de neuf marques différentes. Les analyses physicochimiques ont porté sur le dosage de la teneur en iode par titrage iodométrique, le dosage de la teneur en chlorure de sodium (NaCl), la détermination des matières insolubles et de l’humidité. Résultats. Les résultats obtenus montrent que la teneur en iode varie d’un échantillon à l’autre (p<0,05) et que 77,78% des échantillons sont considérés comme non conformes à la législation algérienne en vigueur, fixée entre 50,55 et 84,25 mg/kg de sel. Cette fraction renferme deux groupes, un exempt d’iode ou du moins à très faible concentration, l’autre, bien que iodé, accuse un déficit important en cet élément (p<0,01). Tous les échantillons sont conformes au regard des autres paramètres, excepté pour le NaCl où seulement 44,44% des échantillons sont déclarés conformes. L’analyse de variance montre que tous les paramètres dépendent significativement de l’échantillon testé. Conclusion. Cette étude doit être confortée avec une étude épidémiologique concernant la prévalence des TCI, tout en la généralisant à d’autres régions et en essayant de trouver des liens entre la prévalence de ces derniers et la teneur en iode des sels commercialisés. Toute généralisation, à ce stade s’avère hasardeuse

The Adsorptive Removal of Bengal Rose by Artichoke Leaves: Optimization by Full Factorials Design

Currently, the dye industry is increasing its production as a consequence of the growing need for their products in different manufacturing sectors, such as textiles, plastics, food, paper, etc... Thereafter, these industries generate very large volumes of effluents contaminated by these dyes, which require proper removal treatment before final discharge of the effluents into the environment. In this study, artichoke leaves were used as an economical and eco-friendly bio-adsorbent for Bengal Rose (BR) dye removal. Bio-adsorbent obtained from artichoke leaves was ground to powder size. The resulting powder was characterized by different methods, such as Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy(SEM), X-ray Diffraction (XRD), Fourier transfer infrared (FTIR), pH at point of zero charge (pHpzc), equilibrium pH, iodine number, methylene blue number, phenol number, density, Energy dispersive X-ray spectroscopy (EDX) and Thermo-gravimetric analysis (TGA). Thereafter, the bio-adsorbent was used to study its capability for removing BR dye by testing contact time, initial concentration of dye and temperature. The results show that the saturation of bio-sorbent was reached after 40 min and the removal rate of BR dye by artichoke leaves powder (ALP) was 4.07 mg/g, which corresponds to a removal efficiency of 80.1%. A design of experiences (DOE) based on a two-level full factorial design (23) was used to study the effects of different parameters, such as pH, temperature and bio-adsorbent dosage on BR dye removal efficiency. The obtained results show that the highest removal efficiency was 86.5% for the optimized values of pH (4), temperature (80 °C) and bio-adsorbent dosage (8 g/L). Furthermore, a satisfying accordance between experimental and predicted data was observed. The kinetic and isotherm studies show that the pseudo-second order model simulated adequately the obtained data and it was found that Langmuir and Temkin isotherm models are liable and suitable for evaluating the adsorption process performance. Free energy change of adsorption (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were furthermore calculated to predict the nature of the adsorption process

EFFECT OF DURUM WHEAT BRAN ON GLUCOSE AND LIPID METABOLISM IN DIABETIC RATS.

Introduction: Durum wheat bran is obtained from wheat milling, it’s considered as an excellent source of insoluble dietary fibre. Objective. The aim of this paper was to evaluate the effect of wheat bran (WB) &nbsp;on glucose and lipid metabolism in normal and diabetic rats. Materials and Methods. Twenty-four female rats of "Wistar" were divided into four groups each containing six rats. The first group (NCR) was fed by a control diet while the second group (NCRE) was fed by the experimental diet based on durum wheat bran. For the third and fourth group after streptozotocin (STZ) injection, they were fed by a control diet (DCR) and experimental diet (DRE) respectively. The Blood Glucose (g/L) and weight (g) of these groups was measured at the end of each week for a period of four weeks, the serum lipid parameters in the fasting condition, such as TC, TG, LDL-C and HDL-C were evaluated at the end of the experience. Results. WB was high in dietary fibre (41%). The results show a significant decrease in blood glucose ( p&lt;0.04)&nbsp; and body weight ( p&lt;0.05 ) in DRE group compared to DCR group &nbsp;and non-diabetic groups. No significant difference was observed for cholesterol and triglyceride levels, a difference of p&lt;0.05 for HDL-C was observed between the diabetic experimental diet group and the non-diabetic control diet group. For LDL-C, the difference was observed between the diabetic experimental group and the non-diabetic experimental group (p&lt;0.001). Conclusion Our results indicated that WB exerting a glycemic and a serum lipid regulation effect in experimental diabetic rats

Chemical composition and antioxidant activity of lipids from Ficus carica L. fruits

Samples of oils from seven types of Ficus carica L. fruits from Algeria were investigated through determinations of their chemical characteristics, quantifying sterols and tocopherols, and analysis of the fatty acids profiles using gas chromatography, and evaluation of antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and total antioxidant activity (TAA) using phosphomolybdenum methods. The results show that acid values ranged from 3.14 to 6.95 mg KOH/g indicating on the high amount of free fatty acids in the figs oils. Neutral lipids occupy a very important proportion of the crude figs oils (NL: 60.30–98.40%) compared to glycolipids (GL: 0.58–28.00%) and phospholipids (PL: 0.40-11.70%). Linoleic (11.70–34.74%) and linolenic (1.15–35.27%) were the major unsaturated fatty acids found in lipid fractions, while the main fraction of saturated fatty acid was palmitic. The tocopherols and sterols contents in fig oils ranged from 14.27 to 108.55 mg α-TE/g lipids and from 0.36 to 2.80 mg CE/g lipids respectively. The best inhibition concentration (IC50) of DPPH antioxidant activity was marked by GL (0.23–1.06 g/L) and PL (0.67–1.23 g/L). The strongest TAA was also marked by GL (IC50: 2.84 to 10.08 g/L) and PL (IC50: 3.73–11.30 g/L). This finding demonstrated for the first time that the studied figs oils possessed good antioxidant activity which may be associated with their alleged health benefits