Transport of Water and Gases through EVA/PVC blend films – Permeation and DSC investigations.

The transport of water vapor and gases (oxygen and carbon dioxide) through poly(ethylene-co-vinyl acetate) (EVA) films of different VA content, poly(vinylchloride) (PVC) and EVA/PVC blend films, was analysed from permeation measurements. A plasticization effect of water on the material was observed for EVA films with more than 19% wt. of VA content and for the EVA/PVC blends, while for gas permeation practically all the experimental curves are characterized by a constant diffusion coefficient, whatever the VA content of the copolymer used. The increase in water absorption with the VA content leads to a steady increase in the water permeability of the EVA copolymers. By mixing the glassy PVC polymer with the EVA copolymer (in a rubbery state) reduced water and gas permeability is observed, resulting mainly from the decrease of the diffusivity due to the low segment mobility of the dense PVC material able to create hydrogen bonds between the hydrogen atoms and the Cl-substituted carbon of PVC with VA carbonyls. Compared to EVA copolymers, the EVA/PVC blends with equivalent VA contents are better in terms of selectivity

Camel breeding development project in Tunisia

Camel breeding is of great socio-economic importance in southern Tunisia. Although, the size of the national camel herd has decreased over the years from 120000 to 56000 heads in 2014. Illegal export, low breeding efficiency, social modernization and lack of investment are the major causes of this decline. To remedy this situation, the Tunisian government has established a national program for development and research on camel production. This program is based on grants to farmers to encourage rearing of replacement females and fattening camels; improvement of pastures and water infrastructure, promotion of applied research in specialized centers. Research eff orts are centered on health, nutrition and improvement of rangelands, development of reproductive biotechnologies and genetic improvement. An attempt was carried out to genotype the local breeds of camels. Development of semen preservation and artificial insemination has met several challenges inherent to the peculiarities of reproduction in this species

Projet de développement de l’élevage camelin en Tunisie

Camel breeding is of great socio-economic importance in southern Tunisia. Although, the size of the national camel herd has decreased over the years from 120 000 to 56 000 heads in 2014. Illegal export, low breeding efficiency, social modernization and lack of investment are the major causes of this decline. To remedy this situation, the Tunisian government has established a national program for development and research on camel production. This program is based on grants to farmers to encourage rearing of replacement females and fattening camels; improvement of pastures and water infrastructure, promotion of applied research in specialized centers. Research efforts are centered on health, nutrition and improvement of rangelands, development of reproductive biotechnologies and genetic improvement. An attempt was carried out to genotype the local breeds of camels. Development of semen preservation and artificial insemination has met several challenges inherent to the peculiarities of reproduction in this species. Keywords: Husbandry, reproduction, biotechnologies, Camel, TunisiaL’élevage du dromadaire joue un rôle socio-économique important dans le sud tunisien mais le nombre de dromadaires a connu ces dernières années une diminution importante de 120 000 à 56 000 en 2014. L’exportation illégale, le rendement faible de l’élevage, la modernisation de la vie des personnes et le manque d’investissement dans ce domaine sont les principales causes de cette diminution. Pour remédier à ce problème, l’état tunisien a proposé un programme national de développement et de recherche dans le domaine du dromadaire basé sur (1) l’encouragement des éleveurs par la subvention de l’élevage des femelles de remplacement et l’engraissement des chamelons, (2) l’amélioration des infrastructures dans les pâturages; notamment l’aménagement des points d’eau pour les animaux et (3) la promotion de la recherche appliquée dans les centres spécialisés. Les principaux thèmes de recherche sont axés sur la santé animale, l’alimentation des dromadaires et l’amélioration des zones de parcours, l’insémination artificielle et le transfert d’embryon et la sélection génétique des animaux. Dans le domaine de la biotechnologie de la reproduction, des essais ont été réalisés dans le typage génétique des dromadaires, la conservation du liquide séminal et l’insémination artificielle pour surmonter les difficultés particulières de la reproduction chez le dromadaire. Mots-clés: Élevage, reproduction, biotechnologies, dromadaire, Tunisi