SAID SHEHATA

This paper explores the implications of environmental conditions related to computer-based information systems (CBIS) development and implementation in developing countries. Their different economic, social, infrastructural, educational, cultural, political and legal conditions have important implications for organizational information requirements and cost/benefit considerations. This suggests that strategies based on a systems approach for information systems development in those countries should be adapted to minimize costly mistakes and to increase effectiveness. By examining environmental conditions in developing countries and their effects on the system development process, this paper proposes general directions for CBIS development to organizations in these countries.

Differential scanning calorimetry (DSC) curves and electrical conductivity α were measured for three forms of zeolite-Y, namely NaY, HY and dealuminated HY (DAY). The DSC curves gave dehydration endotherms for all the forms, whereas the σ values have a number of breaks indicating higher mobilities of the charge carriers. NaY exhibited by far the highest conductivity values, mainly resulting from a large number of Na + ions in the presence of freely diffusing water molecules. DSC indicated a lower free diffusion of water molecules in the HY form which, together with a relatively weaker acidity, contributes to its lower σ values despite its high water content. The production of a relatively large percentage of Al 3+ ions in DAY by dealuminating the mother zeolite HY, together with the presence of freely diffusing water in the zeolitic channels (despite the low water content of DAY), results in its σ values being higher than those of HY. © 1990.

Differential scanning calorimetry (DSC) curves and electrical conductivity α were measured for three forms of zeolite-Y, namely NaY, HY and dealuminated HY (DAY). The DSC curves gave dehydration endotherms for all the forms, whereas the σ values have a number of breaks indicating higher mobilities of the charge carriers. NaY exhibited by far the highest conductivity values, mainly resulting from a large number of Na + ions in the presence of freely diffusing water molecules. DSC indicated a lower free diffusion of water molecules in the HY form which, together with a relatively weaker acidity, contributes to its lower σ values despite its high water content. The production of a relatively large percentage of Al 3+ ions in DAY by dealuminating the mother zeolite HY, together with the presence of freely diffusing water in the zeolitic channels (despite the low water content of DAY), results in its σ values being higher than those of HY. © 1990.