The default properties are based on [DuPont2004N], except that
the default value of protonic conductivity (σ = 0.083*U.S/U.cm)
is for the
DuPontTM Nafion® N and NE series
[DuPont2004N].
It is not listed for DuPontTM Nafion® NRE-212
in [DuPont2004NRE].
For more information, please see the PEM model.