Comparaison structurale des acides humiques et du concentré de kérogène du phosphate de Youssoufia riche en matière organique

De nombreux travaux ont été développés sur l’étude de la matière organique contenue dans le phosphate naturel de Youssoufia. La compréhension des mécanismes réactionnels engendrés lors de la calcination, permet d’avoir des renseignements importants sur la structure de la matière organique. Dans un premier temps, nous avons essayé d’extraire les acides humiques et le concentré de kérogène du phosphate noir de Youssoufia. La R.M.N 13C du solide, l’DSC et l’A.T.G ont permis d’identifier les principaux constituants de la matière organique des acides humiques et du concentré de kérogène. Nous avons également étudié la cinétique de dégagement des gaz émanants des acides humiques et du concentré de kérogène, extraits de la matière organique. Nous nous sommes intéressés principalement aux dégagements du CO2, H2 et CH4 :- Le CO2 semble avoir presque la même allure pour le concentré de kérogène et les acides humiques. La position des maxima des pics de production de CO2 est la même pour les deux échantillons.- L'hydrogène et le CH4 se dégagent des acides humiques et du concentré de kérogène en une seule vague.Mots-clés : Phosphate, matière organique, IR-FT, RMN 13C du solide pyrolys

Effect of benzimidazole fungicides and calcium chloride on Alternaria alternata and Penicillium expansum rot during storage of pears

The present study assayed the effect of the fungicides benomyl, methyl-thiophanate, thiabendazole and calcium chloride on fungal decay of pears caused by Alternaria alternata and Penicillium expansum. Both in vitro and in vivo, the efficacy of fungicides alone against the two fungi was shownto be weak and without any practical interest. In vitro, CaCl2 alone was tolerated by both species at more than 4%. In vivo and at low temperature, CaCl2 significantly reduced fungal decay when used at 4 and 6%. The association fungicides - CaCl2 (4%) allowed a better control of A. alternata

Antibacterial effects and toxigenesis of Penicillium aurantiogriseum and P. viridicatum

The toxigenesis of one Penicillium aurantiogriseum and one Penicillium viridicatum isolates was investigated. Sterile culture filtrates of both fungi had a clear antibacterial effect only against Bacillus subtilis. The effect on B. subtilis varied with amount of filtrate used and temperature. The antibacterial activity of chloroform extracts varied with the nature of media used to grow the fungi. Different mycotoxins were identified in the fungal cultures using thin-layer chromatography. P. aurantiogriseumwas found to produce penicillic acid, terrestric acid and aurantiamine, while penicillic acid, terrestric acid, brevianamide A and xanthomegnin were produced by P. viridicatum

Hydrological simulation (Rainfall-Runoff) of Kalaya watershed (Tangier, Morocco) using Geo-spatial tools

In this study, the hydrologic modeling software HEC-HMS coupled with geo-spatial tools such as GIS and remote sensing have been used to establish the hydrological model in Kalaya watersheds located southeast of Tangier city (northwestern Morocco). The purpose is to simulate rainfall-runoff process in Kalaya watershed and to predict peak discharge for different return periods. In this hydrological simulation, SCS Curve Number method was selected as an infiltration part of the HEC-HMS model and direct runoff was transformed by US SCS unit hydrograph (UH). This model has allowed to establish unit hydrograph and various meteorological and hydrological processes for the flood hydrograph, as well as the estimation of runoff for 200, 100, 50, 20, 10, and 5 years return periods