231 research outputs found

    Signal propagation in transmission lines with losses using fibonacci wave functions

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    In this paper, the general model for an infinite LC ladder network using Fibonacci wave functions that were applied to lossless transmission lines will be extended to transmission lines including losses. The general model that was derived from a first order system transfer function representing a simple RC or RL circuit will be used to model and analyze transmission lines presenting losses. The LC ladder network model can be applied to any order for each inductor current with its parasitic rc resistor and for each capacitor voltage with its parasitic rL  resistor. The extension of the proposed general model to transmission lines with losses is subject to Heaviside condition for both resistors rc  and r

    Incorporation du coprah et des cuticules de cacao et d’arachide dans l’aliment du (tilapia du nil( (Oreohromis niloticus, linné, 1758) eleve en etang : Effet sur la croissance et la composition biochimique

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    Dans le but de réduire le coût de l’alimentation du tilapia en élevage, quatre aliments exogènes pulvérulents dont un industriel (Ivograin) servant de référence (AR) et trois tests locaux (A1, A2 et A3) formulés uniquement à base de sous-produits locaux ont été utilisés. La composition de base des aliments tests est : A1 (cuticules de de fève de cacao, son de maïs, tourteaux de soja et coton) ; A2 (cuticules de graine d’arachide, son de maïs, tourteaux de soja et coton) et A3 (tourteaux de coprah, soja et coton et son de maïs). Tous les aliments titrent environ 28 % de protéines. L’expérience est conduite à la ferme « Blondey » (Côte d’Ivoire) sur des juvéniles de Oreochromis niloticus d’un poids initial de 33,3 ± 0,4 g. Des juvéniles ne recevant pas d’aliment exogène ont servi de lot témoin (At) pour apprécier l’effet de l’aliment endogène. La densité de stockage était de 2 poissons/m2. Trois étangs par traitement ont été utilisés. La ration journalière a été distribuée à 9 h et à 15 h. Après 180 jours d’expérience, les poids moyens finaux ont atteint des valeurs respectives de 273,42 ± 26g ; 295,08 ± 18,5 g ; 352,1 ± 20,7g ; 309,38 ± 22,3 g et 101,06 ± 4 g pour A3, A2, A1, AR et At. Au niveau des aliments exogènes, le meilleur quotient nutritif (Qn= 2,22) et de croissance journalière (1,77 g/jour) ont été obtenus avec A1. Le plus grand Qn (2,88) et la plus faible croissance journalière (1,33g /jour) sont enregistrés avec A3. La comparaison de tous les lots indique que la plus faible croissance (0,38 g/jour) est enregistrée chez les poissons non nourris à l’aliment exogène (At). Les lipides corporels (16 - 17 %) sont plus élevés chez les poissons nourris aux aliments tests que ceux des lots de référence (14 %) et témoins (13 %). Par rapport à l’aliment AR, les aliments tests réduisent le coût de revient de l’aliment et le coût de l’alimentation par unité de prise de poids de 15 - 18 % et 3,1 - 27,4 %, respectivement.Mots clés : Aliments, arachide, cacao, coprah, cuticules, Oreochromis niloticusEnglish AbstractIncorporation of coconut oil cake, cocoa bean shell and peanut skin in diet for nile tilapia (Oreohromis niloticus, linné, 1758) reared in pond : Effect on growth and biochemical compositionIn order to reduce feeding cost of rearing tilapia, four powdered diets including an industrial product (Ivograin) (as reference = AR) and three practical diets (A1, A2 and A3) formulated using local by-products were used. Formulated diets were designated as A1 (cocoa bean shell, corn bran, soybean oil cake, cottonseeds oil cake, premix), A2 (peanut skin, corn bran, soybean oil cake, cottonseeds oil cake, premix) and A3 (corn bran, soybean oil cake, cottonseeds oil cake and coconut oil cake). The four diets contained approximately 28 % crude protein. The experiment was carried out at farm « Blondey » (Ivory Coast) on fingerlings Oreochromis niloticus with an initial body weight of 33.3 ± 0.4g. In addition, fingerlings non-fed with exogenous diet were used as control group to assess the impact of the natural food. The used stocking density was 2 fish/m2. Three replicate ponds were assigned to each of the treatment. Fish were fed twice daily (9.00 h and 15.00 h). After 180 days of experiment, the final body weight observed were respectively 273.42 ± 26 ; 295.08 ± 18.5 ; 352.1 ± 20,7 ; 309.38 ± 22.3 g and 101.06 ± 4 g for A3, A2, A1, AR and At. Considering the four diets (A1, A2, A3 and AR), the best daily weight gain (1.77 g/day) and feed conversion ratio (2.22) were obtained with A1 which were significantly different (p < 0.05) from values obtained for the other groups. The poorest weight gain (1.33 g/day) and the highest feed conversion ratio (2.88) were recorded for A3. The comparison of all groups (A1, A2, A3, AR and At) revealed that the poorest value of the daily weight gain (1.33 g/day) was recorded for the control group (At). Fat deposition was highest (16 - 17 %) in fish fed practical diets, while fish fed diets AR and control fish (At) recorded respectively (14 %) and (13 %). Practical diets reduced the feed cost and feeding cost per unit of weight gain by 15 - 18 % and 3.1 - 27.4 %, respectively.Keywords : Diets, peanut skin, cocoa bean shell, coconut oil cake, Oreochromis niloticu

    Systematic approach furthering confirmation measures of safety critical automotive systems

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    Different system elements are developed independently from diverse suppliers and teams before being integrated together into safety critical automotive systems such as steering or braking systems by a manufacturer. It must be guaranteed that, despite this independent development, the achievement of the safety requirements for the overall system can be demonstrated. The necessary agreements and the integration of the necessary safety information for the overall system generate higher extra costs. In order to reduce development time and cost, systematic reuse can be a solution to engineering the required artifacts. Reassessment represents an additional source of cost. Even small modifications of a system or exchanging a component after it has been certified necessitates a reassessment. The effort required for reassessment, in many cases reaches the original effort of certification for the complete system or even exceeds it. To minimize the effort and cost of a reassessment, this paper introduces a theoretical foundation of a model-based engineering approach to reuse a safety case and change only the modified parts. This paper presents a reusability framework to support the distributed development environment together with the different composition scenarios with respect to ISO26262. A further benefit of this approach is that for development of variants in product-line, the Safety assessment process can now be easily expressed and managed

    Caracteristiques des systemes de culture a base d’anacardier dans les zones de production de l’anacarde de la Côte D’Ivoire

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    L’anacardier (Anacardium occidentale L.) est un arbre aux intérêts multiples et variés, qui contribue au développement socio-économique de la Côte d’Ivoire. Si les premières plantations étaient destinées à lutter contre la dégradation de l’environnement dans les régions de savane, l’anacarde est aujourd’hui devenu une véritable culture de rente dans le pays. L’objectif de cette étude était de caractériser les systèmes de culture à base d’anacardier (caractéristiques sociales et agronomiques) en Côte d’Ivoire, en vue de favoriser leur amélioration. Pour ce faire, une enquête a été menée auprès de 1182 producteurs d’anacarde, répartis dans quatre zones de production (Centre, Nord, Nord-Est et Nord-Ouest). Les résultats ont montré que les producteurs d’anacarde sont majoritairement des exploitants dont la moyenne d’âge est comprise entre 45 et 50 ans, avec une prédominance d’hommes. La plupart des producteurs pratiquent la rotation des combinaisons de cultures au stade juvénile des arbres (< 10 ans). En outre, les rotations de cultures varient selon les zones agro-écologiques. Globalement, les céréales sont la principale culture dans les rotations dans le Nord (67,5%) et le Nord-Ouest (74,8%), avec une prédominance du maïs. En revanche, les tubercules, avec l’igname en tête, dominent les rotations dans les zones du Centre (59,8 %) et du Nord-Est (78,8 %) du pays. &nbsp

    Contamination du lait caillé et de l’oeuf consommé en Côte d’Ivoire par des pesticides organochlorés

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    La présente étude vise à évaluer l’aspect sanitaire de l’alimentation humaine à travers deux produits à forte consommation en Côte d’Ivoire : le lait caillé et l’oeuf. Ainsi, 30 échantillons de lait caillé ont été achetés et 30 échantillons d’oeufs de poulet ont été collectés dans trois fermes dans la ville d’Abidjan. Ces échantillons ont été traités dans le but de déterminer les résidus de 12 POC (Pesticides OrganoChlorés). Les analyses ont été réalisées au CG sur colonne capillaire avec un détecteur à capture d'électrons. Les résultats observés révèlent une contamination du lait caillé et de l’oeuf par 5 POC. Ainsi, des charges moyennes en μg/kg des isomères hexachlorocyclohexane (HCH) allant de 0,125 à 0,997 et de 1,870 à 35,907, de l’endosulfan allant de 0,045 à 0,563 et non détecté, de la dieldrine allant de 0,025 à 0,263 et de 5,727 à 69,710 et du Dichlorodiphenyltrichloroethane (DDT) et métabolites allant de 0,133 à 0,813 et de 21,105 à 75,22, ont été respectivement déterminées dans le lait caillé et dans l’oeuf. La teneur résiduelle moyenne des isomères HCH, des cyclodiènes (dieldrine, et endosulfane) et du DDT et ses métabolites constituent respectivement 40%, 40% et 20% de la moyenne du total des POC mesurés dans le lait caillé et respectivement 20%, 20% et 60% de celle mesurée dans l’oeuf.Mots-clés: pesticides organochlorés, lait caillé, oeuf, Côte d’Ivoire. Contamination of the curdled milk and the egg consumed in Ivory Coast by organochlorinated pesticides This study aims to determine the levels of organochlorinated pesticides (OCPs) in the curdled milk and egg. Thus, 30 samples of curdled milk were purchased and 30 egg samples were collected from three farms in the area of the lagoons. These samples were processed in order to determine the residues 12 OCPs. Analyses were performed by GC capillary column with electron capture detector. The observed results indicate contamination of curdled milk and egg by 5 OCPs. Thus, average loads in μg/kg of hexachlorocyclohexane (HCH) isomers ranging from 0.125 to 0.997 and 1.870 to 35.907, endosulfan ranging from 0.045 to 0.563 and undetected, dieldrin ranging from 0.025 to 0.263 and 5.727 to 69.710 and dichlorodiphenyltrichloroethane (DDT) and metabolites ranging from 0.133 to 0.813 and 21, 105 to 75.22, respectively, were determined in the curdled milk and egg. The average residual HCH isomers, cyclodiene (dieldrin and endosulfan) and DDT and its metabolites is respectively 40%, 40% and 20% of the average total OCPs measured in curdled milk and respectively 20%, 20 % and 60% of that measured in the bud.Keywords: organochlorinated pesticides, curdled milk, egg, Ivory Coast

    Review on the cost optimization of microgrids via particle swarm optimization

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    Economic analysis is an important tool in evaluating the performances of microgrid (MG) operations and sizing. Optimization techniques are required for operating and sizing an MG as economically as possible. Various optimization approaches are applied to MGs, which include classic and artificial intelligence techniques. Particle swarm optimization (PSO) is one of the most frequently used methods for cost optimization due to its high performance and flexibility. PSO has various versions and can be combined with other intelligent methods to realize improved performance optimization. This paper reviews the cost minimization performances of various economic models that are based on PSO with regard to MG operations and sizing. First, PSO is described, and its performance is analyzed. Second, various objective functions, constraints and cost functions that are used in MG optimizations are presented. Then, various applications of PSO for MG sizing and operations are reviewed. Additionally, optimal operation costs that are related to the energy management strategy, unit commitment, economic dispatch and optimal power flow are investigated. © 2019, The Author(s)

    Management of Vesicouterine fistulae during fistulae surgical caravan in Cote d'Ivoire

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    Background: The urogenital fistula (UGF) which designate a solution of continuity between the urinary and genital tracts in women, are divided into several entities of variable gravity. The objective of this study was to describe the epidemiological, clinical and therapeutic characteristics of patients treated for vesicouterine fistula during ‘fistulas surgical caravans’.Methods: This was a prospective and descriptive study on a cohort of 34 patients treated for Vesico-uterine fistulae during ‘‘fistulas surgical caravans '' from 1st January 2012 to 31st December 2016.Results: Vesico uterine fistulae represented 2.1% of all urogenital fistulae treated. At the time of occurrence of fistulas, the average age of the patients stay was 33.3 years, and the majority was not educated (88.2%), lived in rural areas without occupations (73.5%). All the fistulae were secondary to childbirth, the majority of which took place on a scarred uterus (67.6%). And this childbirth responsible for the fistula was done by caesarean section in 97.7% of cases. Then the average duration of the fistula before management was 6 years. Finally, all the patients were operated by the same surgical technique, made by abdominal extra peritoneal transvesical way. The cure rate after this surgical technique was 97.1% (33 patients). The only case of failure required a second operation by another technique which permitted the healing of the patient.Conclusions: The vesicouterine fistulae were rare and the satisfactory results of their management invite us to sustain these surgical caravans and ensure their widespread

    Relationships between morphometric characteristics of brackishwater prawn, Macrobrachium macrobrachion (Herklots, 1851), of Côte d’Ivoire (West Africa)

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    The present study describes the length-weight relationship (LWR), length-length relationship (LLR) and condition factor of the wild population of the shrimp Macrobrachium macrobrachion from the rivers of Côte d’Ivoire (West Africa). Samples were randomly collected from small-scale shrimp fisheries using bamboo traps. Of the thirteen analyzed morphometrics characters, only the second pleura width significantly varies between males (13.11 mm) and females (14.78 mm). All relationships between the considered variables were significantly linear, r^2 ranging from 0.66 to 0.97. For length-length relationships, the allometry coefficient varied depending on groups, environments and characters, and ranged between 0.64 and 1.26. The three allometry types (negative allometry, isometry and positive allometry) were observed in this relation. In length-weight relationship, the coefficient ranged from 2.02 to 2.78, indicating a negative allometry. The condition factor values showed that females (0.70±0.06) were in better condition than males (0.657±0.07). Overall, the condition factor followed an east-west gradient, decreasing from eastern (0.70) to western (0.63) regions. These results constituted an important biological database on M. macrobrachion from the rivers of Côte d’Ivoire for further studies as ecology, reproductive biology, and aquaculture potentialities of this species
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