Backstepping control of three-phase three-level four-leg shunt active power filter

In this paper, backstepping control for three-level four-leg shunt active power filter (SAPF) system is proposed. The adopted filtering topology requires both a three-dimensional space vector modulation (3DSVM) for controlling the three-level four-leg inverter as well as DC voltage and filter currents control. The regulation of the DC voltage and filter currents is accomplished by backstepping controllers. The voltage-balancing control of two split DC capacitors of the three-level four-leg SAPF is achieved using three-level three-dimensional space vector modulation equipped by a balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The simulation results show the effectiveness of the proposed filtering system in terms of the compensation of the harmonics and the zero sequence current and the operation at unity power factor.Keywords: shunt active power filter; three-dimensional space vector modulation; multilevel four-leg inverter; backstepping control; synchronous reference frame theory

COMPARISON BIOCHEMICAL OF THE DESCENDANTS RESULTING FROM FIVE BACK CROSS-COUNTRY RACE GENERATIONS AND THEIR INHERITANCE OF DURUM WHEAT CROSSES

This study was carried out to compare, on  the basis of some biochemical nature, five generations of backcrossing resulting from six crosses between  four varieties of durum wheat (M,  W,  S and P) as three crosses  MxW,  MxS, and PxW along with their reciprocals  WxM,  SxM, and WxP. A sufficient knowledge of the biochemical characteristics of the grain and their genetic transmissions, allows their use in selection.  These characteristics can be used as criteria for selection of seeds for more judicious orientation. From the obtained results, a relative variability appeared at the various varieties and their descendants for the studied parameters (the weight of thousand grains, content of protein, moisture content, the volume of sedimentation and capacity of hydration of the gluten). Generally, the studied samples are relatively rich in proteins.  The descendants of cross MxW have on average a significant volume of sedimentation, they can be used for wheat improving.  For the moisture content, cross MxW records the greatest value with a more significant descendants BC5.  With regard to the polymorphism of the glutenines, some bands were transmitted by the recurrent parent varieties used as female parents

Preservation du concentre de tomate par un agent antifongique (Huile essentielle du citron)

Les huiles essentielles ont des molécules naturelles considérées comme antioxydants, antimicrobiens servant comme conservateur naturel pour préserver l’aliment des différentes altérations. Cette étude a pour objectifs de valoriser les écorces de Citrus limon de la variété « Euréka » par extraction de ses huiles essentielles, d’évaluer in vitro l’activité antifongique de ces huiles extraites par deux modes: hydrodistillation (HEH) et pression à froid (HEP), et enfin les appliquer au concentré de tomate. Le rendement moyen en huile essentielle extraite par hydrodistillation est de 2,20±0,773% et celui de l’huile extraite par pression à froid est de 0,87±0,025%. La composition de ces huiles a été analysée par chromatographie en phase gazeuse couplée à la spectrométrie de masse (GC/MS). Les résultats nous ont permis d’identifier 30 constituants représentant 97,81% et 97,42% de l’huile essentielle totale HEH et de celle de HEP, respectivement. Les composants principaux étaient le limonène suivi du α-pinèneet de γ-terpinène. Le test de l’activité antifongique des huiles essentielles du citron a été réalisé par la méthode des aromatogrammes et a montré que cette huile possède une activité antifongique plus au moins intéressante. Les concentrations minimales inhibitrices (CMI) ont été estimées par la méthode de dilution d’agar. Les souches fongiques telles que Aspergillus terreus, Aspergillus niger, Aspergillus flavus, Trichoderma  longibrachiatum, Fusarium oxysporum et Fusarium culmorum ont révélé une nette sensibilité vis-à-vis des huiles extraites avec des CMIs qui varient entre 350 et 600 μg.ml-1 pour HEH et entre 180 à 500μg.ml-1 pour HEP. Ces résultats ont été confirmés par l’application des huiles HEH et HEP au concentré de tomate qui a présenté une meilleure résistance à la contamination fongique par rapport au témoin (sans huiles essentielles) révélant une modification de lacouleur (le rouge vire vers le marron). L’application de ces huiles essentiellesau concentré de tomate nous a permis de déduire que cette huile limite l’altération par les moisissures et le conserve un peu longtemps (deux mois). Essential oils have natural molecules considered as antioxidants, and antimicrobial substances serving as natural preservatives used to preserve the food from various alterations. The objectives of this study were to enhance the use of Citrus limonpeel of the "Eureka" variety by extracting its essential oils, to evaluate in vitro the antifungal activity of these oils extracted by two methods: hydrodistillation (HEH) and cold pressure (HEP), and finally apply them to the tomato concentrate in order to see their effect on fungi (molds). The average yield of essential oil extracted by hydrodistillation is 2.20 ± 0.773% and that of the oil extracted by cold pressing is 0.87 ± 0.025%. The composition of these oils was analyzed by gas chromatography coupled with mass spectrometry (GC / MS). The results allowed us to identify 30 constituents representing 97.81% and 97.42% of the total essential oil HEH and that of HEP, respectively. The main components were limonene followed by α-pinene and γ-terpinene. The test of the antifungal activity of essential oils of lemon has been carried out by the aromatogrammes method; it showed that this oil has an antifungal activity. Minimum inhibitory  concentrations (MIC) were estimated by the agar dilution method. The fungal strains (molds) Aspergillus terreus, Aspergillus niger, Aspergillus flavus, Trichoderma longibrachiatum, Fusarium oxysporum and Fusarium culmorum revealed sensitivity to extracted oils with MICs that vary between 350 and 600 μg.ml-1 for HEH and between 180 and 500 μg.ml-1 for HEP. These results were confirmed by the application of HEH and HEP oils to tomato concentrate, which showed better resistance to fungal contamination compared to the control (without essential oils) revealing a change in color (red turns to brown). The application of these essential oils to tomato concentrate has allowed us to deduce that this oil limits the damage caused by molds and keeps it safe for about two months

Distributed detection system with pulse-to-pulse correlation

In this paper, we study the performances of a distributed system with several pulses partially correlated . The local decision of each sensor is transmitted to the data fusion center where a global decision is determined . The Neyman-Pearson threshold of th e local sensor is also obtained . The effects of the pulse integration and the pulse-to-pulse correlation are studied and discussed . Th e decision rules considered are AND, OR, and Majority .Dans cet article, nous présentons les performances d'un système de surveillance décentralisé où chaque détecteur local effectue, pour l'élaboration d'une décision, l'intégration d'observations partiellement corrélées d'une cible supposée de modèle Rayleigh. Les décisions locales sont transmises au centre de fusion où une décision globale est obtenue. Le seuil de Neyman-Pearson, relatif à chaque détecteur local, est déterminé. Les effets de l'intégration des observations et de leur corrélation « pulse-to-pulse » sont aussi étudiés et discutés. Trois règles de fusion de données sont considérées, en l'occurrence « AND », « OR » et « Majority »

Neurosurgical management of anterior meningo-encephaloceles about 60 cases

Anterior meningo-encephaloceles (AME) are congenital malformations characterized by herniation of brain tissue and meninges through a defect in the cranium, in frontal, orbital, nasal and ethmoidal regions. The management of this complex congenital malformation is controversial according to whether use, an intracranial, extra-cranial or combined approach. This is the first largest series published in Africa, in which we present our experience in the operative management of AME; we share our recommendation in technical consideration for surgical approach with review of the literature. All patients beneficed of neuro-radiological investigations including Plan X rays, Spiral Three dimensional CT scan and MRI. Ophthalmologic and maxillo-facial evaluations were done in all the cases. MEA are surgically approached in various ways, mainly on the basis of its location and type, by cranio-facial approach in one-step, or in two stages by intracranial approach followed by facial approach, only by cranial approach or facial approach. The surgical results were evaluated in the follow up on the basis of disappearance of cranio-facial tumefaction with correction of hypertelorism. 60 children with AME were treated in our department between January 1992 and December 2012. The mean age at time of surgery was 14 months (20 days to 18 years) with slight men predominance (28 females/32 males). Cranio-facial team operated 21 patients, 16 were operated in two stages by intracranial approach followed by facial approach, 20 cases beneficed the neurosurgical approach and three only the facial approach Some post operative complications were observed: 2 cases of post operative hydrocephalus underwent shunt; CSF fistulas in three cases cured by spinal drainage, one death due to per operative hypothermia, 3 cases of recurrence how needed second surgery. After mean follow up for 80 months (1 year to 19 years) theses techniques permitted a good cosmetics results in 42 cases, average cosmetics results in 8 cases, poor results in 5 cases and worse cosmetics results in 4 cases, The AME are rare conditions we used the multiples approach first intracranial approach followed by facial approach, but after 1998 we used one-step correction by combined approach, only cranial approach when needed or facial correction

Localization of sources with a frequency-hopped signaling sensor array

In this paper, we present a different approach to the problem of estimating the angle of arrivals (AOA's) of D targets in Frequency - Hopped signaling sensors array for active systems, with D smaller than the number of sensor elements, L . This method is based on the application of the Maximum Likelihood Estimator for a new proposed model of received data available in different channels . The simulation results show that this approach improves the resolution in the estimation of the angle of arrivals compared wit h Monotone-Frequency signaling case. Its drawback, however, is that when the Signal-to-Noise Ratio, SNR, is low the performanc e deteriorates and a large number of snapshots is required .Dans cet article, nous présentons une méthode pour la résolution du problème d'estimation des angles d'arrivée de D cibles, par un réseau de L capteurs, où D < L, pour les systèmes actifs émettant des signaux codés en « Frequency Hopped ». Cette méthode est basée sur l'application de l'estimateur du maximum de vraisemblance à un nouveau modèle de données reçues sur différents canaux. Les résultats de simulation montrent que cette approche améliore la résolution des angles d'arrivée des cibles, comparativement à celle de la fréquence monotone. Cependant, quand le rapport signal sur bruit (Signal to Noise Ratio, SNR) est faible, la performance se dégrade et nécessite donc un nombre d'échantillons plus élevé

Fabrication, physicochemical characterization and preliminary efficacy evaluation of a W/O/W multiple emulsion loaded with 5% green tea extract

Emulsões múltiplas complexas possuem excelente habilidade de agregar grandes quantidades de agentes cosméticos funcionais. Este estudo teve por objetivo encapsular grandes volumes de chá verde em uma emulsão múltipla clássica e comparar sua estabilidade com a emulsão múltipla sem o extrato do chá verde. Emulsões múltiplas são desenvolvidas usando cetil dimeticona copoliol como emulsificante lipofílico e o clássico polissorbato-80 como emulsificante hidrofílico. As emulsões múltiplas foram avaliadas por meio de vários aspectos fisico-químicos como condutividade, pH, análise microscópica e reologia. Estas características foram observadas por um período de 30 dias sob diferentes condições de armazenamento. Testes de proteção da pele in vivo e in vitro foram realizados para ambos os tipos de emulsões testadas, i.e. com o ativo em estudo (MeA) e sem ativo (MeB). Ambas as formulações apresentaram características comparáveis no que diz respeito aos diferentes fatores físico-químicos avaliados sob diferentes condições de armazenamento. A análise reológica mostrou que as formulações apresentaram comportamento pseudo-plástico sob contínuo estresse de cisalhamento. Os resultados dos testes in vivo e in vitro sobre a proteção da pele revelaram que a formulação ativa promoveu efeitos comparáveis à formulação controle. Nossos dados mostraram que emulsões múltiplas estáveis poderiam ser escolhas promissoras para a aplicação tópica do chá verde. Entretanto, a fórmula das emulsões múltiplas apresentadas neste estudo precisam ser melhoradas no que diz respeito ao pH, condutividade e viscosidade aparente.Complex multiple emulsions have an excellent ability to fill large volumes of functional cosmetic agents. This study was aimed to encapsulate large volume of green tea in classical multiple emulsion and to compare its stability with a multiple emulsion without green tea extract. Multiple emulsions were developed using Cetyl dimethicone copolyol as lipophilic emulsifier and classic polysorbate-80 as hydrophilic emulsifier. Multiple emulsions were evaluated for various physicochemical aspects like conductivity, pH, microscopic analysis, rheology and these characteristics were followed for a period of 30 days in different storage conditions. In vitro and in vivo skin protection tests were also performed for both kinds of multiple emulsions i.e. with active (MeA) and without active (MeB). Both formulations showed comparable characteristics regarding various physicochemical characteristics in different storage conditions. Rheological analysis showed that formulations showed pseudo plastic behavior upon continuous shear stress. Results of in vitro and in vivo skin protection data have revealed that the active formulation has comparable skin protection effects to that of control formulation. It was presumed that stable multiple emulsions could be a promising choice for topical application of green tea but multiple emulsions presented in this study need improvement in the formula, concluded on the basis of pH, conductivity and apparent viscosity data

Methidathion-induced hematological, biochemical and hepatohistological alterations in rat: Ameliorative effects of selenium and zinc

The aim of this study was to determine the effect of a sub-acute 4-week exposure to methidathion (MD) on the hematological system and hepatic integrity of rats. We also assessed whether co-administration of micronutrients such as selenium (Se) and zinc (Zn) prevented MD-induced hepatic damage. Rats were randomly divided into four groups of six each: the first group served as a control which received standard diet, the second group received both Se (0.5mg/kg of diet) and Zn (0.227 g/l drinking water), the third group received only MD (5 mg/kg b.w. by gavage using corn oil as a vehicle), and the fourth group received MD and combined selenium and zinc. After four weeks, exposure to MD induced a significant increase in plasmatic activities of AST, ALT, ALP, LDH, and liver malondialdehyde level. In contrast, reduced glutathione level (GSH), and the activities of catalase (CAT), superoxide dismutase (SOD), and the glutathione peroxidase (GPx) content of hepatic tissue decreased significantly. Moreover, treatment with Se and Zn in MD-treated rats maintained all the biochemical parameters cited above. In conclusion, the obtained results indicate the ability of Se and Zn to attenuate the MD-induced liver and erythrocytes oxidative damage.Key words: Biochemical studies, liver, methidathion, oxidative stress, rat, selenium, zinc