Modelling of influential parameters on a continuous evaporation process by Doehlert shells

The modelling of the parameters that influence the continuous evaporation of an alcoholic extract was considered using Doehlert matrices. The work was performed with a wiped falling film evaporator that allowed us to study the influence of the pressure, temperature, feed flow and dry matter of the feed solution on the dry matter contents of the resulting concentrate, and the productivity of the process. The Doehlert shells were used to model the influential parameters. The pattern obtained from the experimental results was checked allowing for some dysfunction in the unit. The evaporator was modified and a new model applied; the experimental results were then in agreement with the equations. The model was finally determined and successfully checked in order to obtain an 8% dry matter concentrate with the best productivity; the results fit in with the industrial constraints of subsequent processes

La unidad didáctica como estrategia para fortalecer la escritura argumentativa en el grado 401 del colegio nacional Nicolás Esguerra -jornada nocturna.

El presente trabajo de investigación surge de la necesidad de mejorar los niveles de coherencia y cohesión en la producción escrita, específicamente de textos argumentativos en los estudiantes de la jornada nocturna, ciclo cuarto, del curso 401, del Colegio Nacional Nicolas Esguerra. Para la comprobación de la problemática de esta investigación, se utilizaron diversos instrumentos: el taller diagnóstico, con el cual, se logra identificar el nivel de redacción de los estudiantes, se realizan actividades que permiten revisar el nivel de conceptualización frente al proceso argumentativo. Por último, se realiza una encuesta de carácter autorreflexivo que tuvo como objetivo indagar en los hábitos de lectura que poseen los estudiantes.Universidad Libre - Facultad de Ciencias de Educación - Licenciatura en Español y Lenguas Extranjera

Solvent effect modelling of isocyanuric products synthesis by chemometric methods

Chemometric tools were used to generate the modelling of solvent e¡ects on the N-alkylation of an isocyanuric acid salt. The method proceeded from a central composite design applied on the Carlson solvent classification using principal components analysis. The selectivity of the reaction was studied from the production of different substituted isocyanuric derivatives. Response graphs were obtained for each compound and used to devise a strategy for solvent selection. The prediction models were validated and used to search for the best selectivity for the reaction system. The solvent most often selected as the best for the reaction is the N,N-dimethylformamide

Removal of lead (II) ions from synthetic and real effluents using immobilized Pinus sylvestris sawdust: Adsorption on a fixed bed column,

Abstract The purpose of this work was to evaluate the potential of Pinus sylvestris sawdust, in a continuous flow removal of lead (II) ions from synthetic and industrial aqueous effluents. The kinetic parameters obtained in a batch process were used to scale-up the process on a minicolumn and to choose the breakthrough model. The column experimental data concerning the volumes treated were correlated using the bed depth service time model. These experimental data closely fitted the bed depth service time model at 10% of the breakthrough curve. The results from the bed depth service time model on the mini-column were then used to design a pilot plant adsorption unit. The performance of the pilot plant column accurately agreed with that obtained from the mini-column. The experiments carried out in a dynamic reactor allowed to bring out the influence of various parameters on the efficiency of the P. sylvestris sawdust. In addition, the process was checked for the treatment of industrial aqueous effluents on a pilot plant scale and the results were in accordance with those obtained from synthetic effluents

RESPONSE SURFACE OPTIMIZATION AND MODELING OF AMMONIUM CHLORIDE ACTIVATION PROCESS OF BENTONITE

Ce travail a consisté en l‟optimisation et la modélisation de l‟activation d‟une bentonite avec le chlorure d‟ammonium en utilisant la méthode des plans d‟expériences, et en particulier la méthodologie de surface de réponse (RSM). Un plan central composite orthogonal (CCOD), a permis la détermination de l‟influence des effets simultanés et de l‟interaction des paramètres opératoires sur la surface spécifique (SBET). Les paramètres étudiés sont la température de l'activation (50-90°C), le temps de contact (2-6h), le rapport massique liquide/solide (4-7g/g) et la concentration de la solution d‟activation (1-2 mol L-1).Les valeurs optimales des paramètres d‟activation donnant une surface spécifique maximale ont pu être déterminées (température : 98.28°C, temps du contact : 6.828 h, rapport massique liquide/solide : 4.627 g/g, concentration de la solution d‟activation : 0.793 mol L-1). La surface spécifique de l‟argile activée sous ses conditions optimales étant de 87.545 m²g-1 et elle est en bonne adéquation avec la valeur prédite par le modèle (89.9 m²g-1). Le modèle de second ordre obtenu pour la surface spécifique de la bentonite activée est en bonne adéquation avec les résultats expérimentaux. Le traitement d‟une bentonite tunisien avec une solution de chlorure d'ammonium provoque une augmentation de la surface spécifique de 47.3 à 87.545 m² g-1 correspondant à une augmentation de 85%

Populations of the Beet Cyst Nematode Heterodera schachtii Exhibit Strong Differences in Their Life-History Traits Across Changing Thermal Conditions

It is widely accepted that climate has an essential influence on the distribution of species and that temperature is the major abiotic factor that affects their life-history traits. Species with very restricted active dispersal abilities and a wide geographical distribution are thus expected to encompass distinct populations adapted to contrasted local conditions. The beet cyst nematode Heterodera schachtii is a good biological model to study temperature adaptation in populations collected from different environments. Here, we tested the effect of temperature on H. schachtii life-history traits using seven field populations from Morocco, Spain, France, Germany, Austria, Poland and Ukraine. We tested hatching and multiplication rates of each population at different temperatures, as well as hatching rates of each population after storage at different temperatures – simulating survival conditions during the inter-cropping period. Results showed a strong temperature effect on the life-history traits explored. Temperature impact on hatching (at different temperatures and after storage at different temperatures) depended on the origin of populations, separating southern from northern ones. Surprisingly, low temperatures influenced hatching less in southern populations. However, for these populations, a storage period at low temperatures strongly reduce subsequent hatching. Conversely, nematode multiplication was not differentially affected by temperatures, as favorable conditions for the host are also favorable for the parasite. Finally, a significant correlation between the genetic diversity and the level of specialization showed that the less diverse populations were more specialized than the more diverse ones

Temporal sampling helps unravel the genetic structure of naturally occurring populations of a phytoparasitic nematode. 2. Separating the relative effects of gene flow and genetic drift

International audienceStudying wild pathogen populations in natural ecosystems offers the opportunity to better understand the evolutionary dynamics of biotic diseases in crops and to enhance pest control strategies. We used simulations and genetic markers to investigate the spatial and temporal population genetic structure of wild populations of the beet cyst nematode Heterodera schachtii on a wild host plant species, the sea beet (Beta vulgaris spp. maritima), the wild ancestor of cultivated beets. Our analysis of the variation of eight microsatellite loci across four study sites showed that (i) wild H. schachtii populations displayed fine-scaled genetic structure with no evidence of substantial levels of gene flow beyond the scale of the host plant, and comparisons with simulations indicated that (ii) genetic drift substantially affected the residual signals of isolation-by-distance processes, leading to departures from migration–drift equilibrium. In contrast to what can be suspected for (crop) field populations, this showed that wild cyst nematodes have very low dispersal capabilities and are strongly disconnected from each other. Our results provide some key elements for designing pest control strategies , such as decreasing passive dispersal events to limit the spread of virulence among field nematode populations

La France du Centre-Est (Auvergne, Bourgogne, Franche-Comté, Rhône-Alpes)

International audienceDie Region liefert einen zahlenmäβig bisher noch kleinen Bestand an Befunden, die zur Hauptsache den letzten Jahrhunderten vor der Zeitenwende angehören. Zahlreiche alte und neue Entdeckungen von Weihefunden illustrieren die groβe Bandbreite der Kultorte (Flüsse, Quellen, Höhlen, gewisse Siedlungsplätze usw.). Die jüngeren Forschungen belegen auch die Existenz planmäβig errichteter gallischer Kultstätten an Zentralorten oder im ländlichen Bereich. Sie sind aber oft durch kaiserzeitliche Heiligtümer verdeckt. Insgesamt scheint sich die Region Centre-Est vom Beispiel der Belgica durch eine geringere Präsenz von Elementen der Bewaffnung zu unterscheiden. Dies schlägt zugunsten der Nachweise von Weinamphoren und sonstiger Gefäβkeramik, häuslichem Werkzeug und Gerät, Schmuck oder auch Münzen zu Buche. Weil es an entsprechenden Darstellungen und Inschriften mangelt, bleiben die hier verehrten gallischen Gottheiten jedoch anonym.zu Buche. Weil es an entsprechenden Darstellungen und Inschriften mangelt, bleiben die hier verehrten gallischen Gottheiten jedoch anonym.The amount of cult testimonies collected in this area is still thin and, for the most part, they are dated from the last centuries BC. The impressive finding, recent or previous, of votive deposits illustrates the varying kinds and multiplicity of sacred places (rivers, springs, caves, various settlements...). Recent investigations have provided conclusive evidence for Gallic central or rural organized cult sites, often sealed beneath Roman sanctuaries. On the whole, the central-eastern part of Gaul apparently differs from the Belgic pattern by the paucity of weapons compared to the frequency of wine amphorae, pottery, instrumentum domesticum, ornaments and even coins. Yet, Gaulish deities remain anonymous for lack of representations and inscriptions.La région Centre-Est livre un ensemble numériquement encore faible, appartenant essentiellement aux derniers siècles avant le changement d'ère. Les découvertes nombreuses, anciennes ou récentes, de dépôts à caractère votif, illustrent la variété et la multiplicité des lieux cultuels (rivières, sources, grottes, habitats divers, etc.). Les recherches récentes attestent la réalité de lieux de cultes gaulois centraux ou ruraux organisés, souvent masqués par des sanctuaires d 'époque impériale. Globalement, le Centre-Est semble se distinguer du « modèle belge » par une représentation plutôt faible de l'armement au profit des amphores vinaires, de la céramique, de l'instrumentum domestique, de la parure, voire des monnaies... Les divinités gauloises honorées restent anonymes, faute de figurations et d'inscriptions