in this paper, polyacrylamide/chromium acetate gel polymer system was prepared as water shut-off system to control water production in one of the iranian oil reservoirs condition. effect of various parameters such as temperature (90 °c) and water formation from view point of salinity and divalent cations, was evaluated on the gelation kinetic and gel strength using bottle testing method. the re...

a proton nmr method for the drtermination of salvation numbers of alkaline earth cations with hexamethyl phosphoramide (hmpa) in nitromethane (nm) as diluents is described. the method is based on monitoring the resonance frequency of hmpa protons as a function of hmpa / metal ion molar ratio at constant metalion concentration. the average salvation number of cations,  , at any hmpa / metal ion ...

The complexation of Alkali metal cations by the water-soluble p-sulfonic acid calix(4)arenewas thermodynamically characterized using spectrophotometeric data which are consistentwith the formation of a 1:1 complex resulting from electrostatic interactions between thesulfonato groups and alkali metal cations. In this study, we determined the formationconstants (log K) of the complexes and have c...

the complexation of alkali metal cations by the water-soluble p-sulfonic acid calix(4)arenewas thermodynamically characterized using spectrophotometeric data which are consistentwith the formation of a 1:1 complex resulting from electrostatic interactions between thesulfonato groups and alkali metal cations. in this study, we determined the formationconstants (log k) of the complexes and have c...

Thermal behavior of various solid feldspars are different, namely those of bivalent cations show no change in the distribution of Al and Si atoms, whereas feldspars of univalent cations become more disordered with raising temperature. In the latter case Al atoms migrate from the sites they occupe at low temperatures and interchange positions with the Si atoms. At high temperatures (but stil...

thermal behavior of various solid feldspars are different, namely those of bivalent cations show no change in the distribution of al and si atoms, whereas feldspars of univalent cations become more disordered with raising temperature. in the latter case al atoms migrate from the sites they occupe at low temperatures and interchange positions with the si atoms. at high temperatures (but still be...