Solar radiation energy is one of the most important energy sources with increasing penetration into the power supply systems of many countries, due to the reduced environmental impact of its operation. A critical factor of the use of photovoltaic systems is the solar radiation intensity. The computation of solar radiation is a complicated procedure based on many factors. This study attempts to implement an efficient and simply computational procedure with no compromise in accuracy of other models. The proposed method tested in four cities of Greece in order to estimate the solar radiation density for building applications focalizing on photovoltaic technologies. The obtained results was satisfied, so this technique can be used in different real time applications

The assessment of the state of health of the Ebrié lagoon through the analysis of five ETMs (Zn, Cu, Pb, Cr and Cd) by the berries of Azito, M'badon and Koumassi (Cote d’ivoire) in the soft tissues of Oysters, Crassostrea gasar. Seasonal samples were taken from December 2015 to December 2016. Physico-chemical parameters such as pH, salinity and temperature were measured. The average concentrations of MTE show that Azito Bay is the most contaminated. As for the lowest concentrations, they are obtained at the bay of M'badon. Comparisons made on the basis of the seasons showed significant differences. Berries are more concentrated in Pb, Cr and Cd during the low-water season only, while Zn and Cu are more abundant during the rain and flood seasons.">

Résumé : L’évaluation de l’état de santé de la lagune Ebrié a été faite par l’analyse de cinq ETM (Zn, Cu, Pb, Cr et Cd) via les baies (Azito, M’badon et Koumassi) dans les tissus mous des huîtres, Crassostrea gasar. Des prélèvements saisonniers ont été effectués de décembre 2015 à décembre 2016. Les paramètres physico-chimiques tels que le pH, la salinité et la température ont été mesurés. Les concentrations moyennes des ETM montrent que la baie d’Azito est la plus contaminée. Quant aux concentrations les plus faibles, elles sont obtenues dans la baie de M’badon. Les comparaisons faites sur la base des saisons ont montré des différences significatives. Les baies sont plus concentrées en Pb, le Cr et le Cd pendant la saison d’étiage tandis que le Zn et le Cu sont plus abondants dans les baies pendant les saisons  des pluies et de crue.

The effect of the modification of ultrasils and pentasils by alkaline earth, rare earth elements (REE) and Mg²⁺ cations on their acidic and catalytic properties, as well as on the para-selectivity of catalysts in the alkylation reaction of toluene with isopropanol was studied. Comparison of the total catalytic activity of cationic forms of zeolites with their acidity spectrum shows that, along with alkylation of toluene, secondary reactions also occur substantially on REE and Mg forms with a significant concentration of strong acid centres, which leads to a decrease in alkylating selectivity. Therefore, the REE and Mg forms of zeolites exhibit a lower selectivity for p-IPT than the Sr and Ba forms of ultrasils. However, on cationic forms in comparison with the H-form of the zeolite, the content of the p-IPT in the IPT mixture is higher than the equilibrium value, i.e. an increase in selectivity for p-IPT is observed. It was found that the chemical modification of zeolites with cations of Sr²⁺, Ba²⁺, Mg²⁺, Lu³⁺, La³⁺ and Ho³⁺ leads to the formation of Lewis acid sites and to the significant decrease in the concentration and strength of Brensted acidic centers, to the formation of new Lewis acidic centres, which is responsible for an increase in the para-selectivity of the catalyst by p-IPT.