This implements the correlation by Springer et al. [Springer1991] for the ratio of H2O molecules to SO3- units of Nafion® EW 1100 series ionomer.
function lambda_eq extends Modelica.Icons.Function; input Q.NumberAbsolute RH "Relative humidity"; output Real lambda "<html>Mole ratio of H<sub>2</sub>O to SO<sub>3</sub><sup>-</sup></html>" annotation( Dialog(__Dymola_label = "<html>λ<sub>eq</sub></html>")); end lambda_eq;