Return activity coefficient of the substance in the solution
function activityCoefficient extends Modelica.Icons.Function; input SubstanceData substanceData "Data record of substance"; input Modelica.Units.SI.Temperature T = 298.15 "Temperature"; input Modelica.Units.SI.Pressure p = 100000 "Pressure"; input Modelica.Units.SI.ElectricPotential v = 0 "Electric potential of the substance"; input Modelica.Units.SI.MoleFraction I = 0 "Ionic strengh (mole fraction based)"; output Real activityCoefficient "Activity Coefficient"; end activityCoefficient;