DSpace Collection:https://dspace.univ-ouargla.dz/jspui/handle/123456789/185902024-03-29T08:38:44Z2024-03-29T08:38:44ZLES ALGINATES ET LEURS APPLICATIONS EN INGENIERIE: APPLICATION A LA CONSTRUCTION D’UN BIOMATERIAUDJEBRI NassimaBOUKHALFA NadiaBOUTAHALA Mokhtarhttps://dspace.univ-ouargla.dz/jspui/handle/123456789/192472019-05-08T10:55:02Z2018-06-01T00:00:00ZTitre: LES ALGINATES ET LEURS APPLICATIONS EN INGENIERIE: APPLICATION A LA CONSTRUCTION D’UN BIOMATERIAU
Auteur(s): DJEBRI Nassima; BOUKHALFA Nadia; BOUTAHALA Mokhtar
Résumé: Alginates, saccharidic polymers extracted mainly from brown algae of the class of Phaeophyceae, are substances very little known to the general public. Depending on the seaweed used and the desired products, several techniques are possible. To recover sodium alginate, there are two techniques:
- 1st technique: passing through alginic acid,
- 2nd technique: passing through calcium alginate
Alginates find applications in many fields and industries. They are used in the textile, food, pharmacy, printing, ... but all these industries find a common property: the ability to gel this natural product, an origin that is currently very well perceived in our society. Their uses are based on their gelling properties which result in a chelation of divalent cations by monosaccharides, and mainly by guluronic acid, the most commonly used divalent cation being calcium. Finally, technologies such as microencapsulation employ alginate to modify the kinetics of release of the encapsulated active ingredient (s). In the present study, alginate being biocompatible, non-toxic and non-immunogenic, it is a good component for producing a biomaterial. It is within this framework that the experimental part of this study has been carried out, which is part of the theme of the encapsulation of different materials and its use for the protection of the environment. In this context, the objective was to develop an alginate matrix for the construction of a biomaterial, which allows the extraction of contaminants: bacteria, spores, sweat, urine, dyes, pharmaceutical agents heavy metals, etc., in an aqueous medium
- 1ère technique: passage par l’acide alginique,
- 2ème technique: passage par l’alginate de calcium
Les alginates trouvent des applications dans de nombreux domaines et de nombreuses industries. Ils sont utilisés dans l’industrie textile, alimentaire, pharmaceutique, dans l’imprimerie,… mais toutes ces industries y trouvent une propriété commune: la capacité de gélification de ce produit naturel, origine qui est très bien perçue actuellement dans notre société. Leurs usages reposent sur leurs propriétés de gélification qui se traduisent par une chélation des cations divalents par les monosaccharides, et principalement par l’acide guluronique, le cation divalent le plus utilisé étant le calcium. Enfin, des technologies comme la microencapsulation emploient l’alginate en vue de modifier la cinétique de libération du ou des principes actifs encapsulés. Dans la présente étude, l’alginate étant biocompatible, atoxique et non immunogène, il constitue un bon composant en vue de la réalisation d’un biomatériau. C’est dans ce cadre qu’a été effectuée la partie expérimentale de cette étude qui s’inscrit dans la thématique de l’encapsulation des différents matériaux et de son utilisation pour la protection de l’environnement. Dans ce contexte, l’objectif a été de mettre au point une matrice à base d’alginate destinée à la construction d’un biomatériau, qui permet de l’extraction des contaminants: bactéries, spores, sueur, urine, colorants, agents pharmaceutiques, métaux lourds, etc., dans un milieu aqueux.
Description: Algerian Journal of Arid And Environment (AJAE)2018-06-01T00:00:00ZDETECTION OF INHOMOGENEITIES AND BREAK POINTS IN ANNUAL RAINFALL SERIES OF SENEGALREGIONSTRAORE Vieux BoukhalyDIOUF RokhayaNDIAYE Mamadou LamineGODFROYD Ousman RilengarFAYE MoustaphaMALOMAR GiovaniSARR JosephDIAW Amadou TahirouBEYE Aboubaker Chedikhhttps://dspace.univ-ouargla.dz/jspui/handle/123456789/192442019-05-08T10:53:29Z2018-06-01T00:00:00ZTitre: DETECTION OF INHOMOGENEITIES AND BREAK POINTS IN ANNUAL RAINFALL SERIES OF SENEGALREGIONS
Auteur(s): TRAORE Vieux Boukhaly; DIOUF Rokhaya; NDIAYE Mamadou Lamine; GODFROYD Ousman Rilengar; FAYE Moustapha; MALOMAR Giovani; SARR Joseph; DIAW Amadou Tahirou; BEYE Aboubaker Chedikh
Résumé: Annual rainfall data used in this study was provided by National Agency of Civil Aviation and Meteorology measured in 14 stations of 14 regions of Senegal. Standard normal homogeneity test was performed on these data to detect possible climatic accidents. Our main goal was to provide national decision-makers with plausible scenarios of climate change for all regions of the country. It is to equip them to: i) adapt their natural resource management strategies to climate change issues; and ii) strengthen the scientific base for their own benefit. For all 14 stations, the null hypothesis of no break is rejected at the 5% threshold and the break dates are between 1955 and 1971 depending on the region. The comparison of averages across the breaking point shows that this break is down for all 14 stations. The characterization of the mean amplitudes before and after rupture shows that this decrease did not have the same intensity in the 14 regions. Finally, the characterization of the wet and dry sequences shows that the temporal persistence of the drought is not at the same level for the 14 regions. In conclusion, the statistical analysis of the rainfall contributions confirms the dissymmetry and the general downward trend and therefore the low water level in Senegal. Such results suggest the need for water authorities to formulate effective water management policies according to the prevailing and future climatic conditions. Transitional, adaptive and urgent measures may be undertaken by priority according regions.
Description: Algerian Journal of Arid And Environment (AJAE)2018-06-01T00:00:00ZIDENTIFICATION ET CLASSIFICATION GÉOTECHNIQUE DU LŒSS DE GHARDAÏA (SUD ALGERIEN)RAHMANI AsmaaHAZZAB AbdelkrimAIMER Hadjhttps://dspace.univ-ouargla.dz/jspui/handle/123456789/192502019-05-08T10:54:25Z2018-06-01T00:00:00ZTitre: IDENTIFICATION ET CLASSIFICATION GÉOTECHNIQUE DU LŒSS DE GHARDAÏA (SUD ALGERIEN)
Auteur(s): RAHMANI Asmaa; HAZZAB Abdelkrim; AIMER Hadj
Résumé: The most of arid regions have aeolian deposits of loose granular soils. These deposits are lœssial soils. They mainly composed of uniform particles of silt. They are found in large quantities around the world. Some authors suggest that there are deposits of peri-Saharan lœss type. In Africa, some authors were examined the lœss of Tunisia, Libya, Morocco, Egypt and northern Nigeria ... etc. The well-known example of these type deposits has been studied by COUDE-GAUSSEN (1987) on the Matmama plateau in southern Tunisia. In Algeria, some deposits were observed in the Ghardaïa region. The results of the laboratory testing program to determine the geotechnical properties of the Algerian lœss are presented and discussed. The testing set includes particle size distribution, Atterberg limits, carbonate content, methylene blue test, sand equivalent and the chemical analysis. The mechanical characteristics of single shear and Proctor test were also investigated. The results obtained from this research indicate that the Algerian lœss is comparable to those of several parts of the world and quite similar to those of Matmata in southern Tunisia.
Description: Algerian Journal of Arid And Environment (AJAE)2018-06-01T00:00:00ZEXTRACTION DE POLYSACCHARIDES PARIETAUX DES NOYAUX DE DATTES VARIETE GHARSDADDI OUBEKKA LeilaDJELALI Nacer-EddineCHAMBAT GérardRINAUDO Margueritehttps://dspace.univ-ouargla.dz/jspui/handle/123456789/192542019-05-08T10:54:06Z2018-06-01T00:00:00ZTitre: EXTRACTION DE POLYSACCHARIDES PARIETAUX DES NOYAUX DE DATTES VARIETE GHARS
Auteur(s): DADDI OUBEKKA Leila; DJELALI Nacer-Eddine; CHAMBAT Gérard; RINAUDO Marguerite
Résumé: The main objective of our study is the valuation of date pits, considered as a widely available lignocellulosic biomass. As a preliminary step, we analyzed the chemical composition of the dates pits powder, about lipids, proteins and ash content, followed by the extraction of the polysaccharides. The results show that raw date pits powder contains 9% moister, 2,23% ash, 8,25% proteins, 6,58% oil expressed to dry weight. After delignification with sodium chlorite solution, we carried out the solubilization of the hemicelluloses by sodium hydroxide solutions at increasing concentrations 5%, 10% and 17,5 %. The raw date pits of variety «Ghars» is composed of 6,42% insoluble-lignin, 43,48% hemicelluloses, and 12,48% cellulose. The polysaccharides are hydrolyzed by two methods: the first one is the reduction / acetylation method and the second is the method of methylglycosides-O-trimethyls (TMS), then they are analyzed by gas chromatography to determine the quality and quantity of the sugars. The results indicate that mannose is the majority sugar, followed by galactose and glucose. The extraction of hemicelluloses shows that raw date pits of Ghars variety is composed of glucomannan with the ration Man: Glc of 3:1.
Description: Algerian Journal of Arid And Environment (AJAE)2018-06-01T00:00:00Z