The non-ideal behavior arises from: (a) the increase in vapor pressure because of the interaction between different molecular species in the gaseous phase of the mixture (the major contribution); (b) the increase in vapor pressure because of the superimposed pressure of the air on the condensed phase (the
Poynting effect); and (c) the decrease in vapor pressure due to the solution of air in the water condensed phase with which the gas mixture is in equilibrium (the Raoult or Henry's law effect).
Xiao and He [10] gave a unified exact analysis for the Poynting effects of cylindrical tubes at finite strains, made of Hill's class of elastic materials.
He, "A unified exact analysis for the Poynting effects of cylindrical tubes made of Hill's class of Hookean compressible elastic materials at finite strain," International Journal of Solids and Structures, vol.