Diaby S.,University Fhb Of Cocody Abidjan
Journal of Chemistry | Year: 2016
The mobility of the Na+ cations localized at the inner surface of the studied mordenite zeolite depends on the material surface properties. In this work, we show that the activation energy, ΔEhop, relating to the Na+ cation hopping displacement is associated to the surface potential and therefore can be used to get a better insight into the zeolite surface properties. Indeed, when molecules as water are adsorbed at the surface, they modify the surface potential energy and hence influence the value of ΔEhop. If the adsorbed molecules are polar they directly interact with the cations which become more mobile. The more the ΔEhop value is, the less the amount of adsorbed water molecules is. Alterations of the ΔEhop value with respect to the amount of adsorbed water molecules are interpreted using the Dubinin model which is based on simple adsorption principle. © 2016 Sekou Diaby.
Diawara A.,University Fhb Of Cocody Abidjan |
Yoroba F.,University Fhb Of Cocody Abidjan |
Kouadio K.Y.,University Fhb Of Cocody Abidjan |
Kouassi K.B.,University Fhb Of Cocody Abidjan |
And 3 more authors.
Advances in Meteorology | Year: 2014
Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of climate at Lamto (6.13°N, 5.02°W) in Côte d'Ivoire. A combined pluviothermal index is used to identify climate regions of West Africa. The interdecadal change of the climate is analyzed along with a discussion on the West African Monsoon (WAM) circulation. The impact of vegetation is also analyzed. It is shown that Lamto has mainly a subhumid climate but, in some particular years, this area has a humid climate. Two decades (1962-1971 and 2002-2011) exhibit rainfall excess and the last three ones (1972-1981, 1982-1991, and 1992-2001) show a rainfall deficit that affected West Africa in the early 1970s. The meridional wind field from 1000 hPa to 700 hPa is used to study the WAM variability. The level of the WAM is the lowest (860-890 hPa) during the active period of the northern wind coming from the Sahara desert (November-February). During 1962-1971 and 2007-2009, the depth of the monsoon at Lamto reaches 300 hPa with an increase in the rainfall. A relationship between potential evapotranspiration and the climate highlights rainfall deficit in 1969 and rainfall excess in 2001-2011. © 2014 A. Diawara et al.