function specificHeatCapacityCp_duX input Modelica.SIunits.Density d "Density"; input Modelica.SIunits.SpecificInternalEnergy u "Specific internal energy"; input Modelica.SIunits.MassFraction X[nC] = reference_X "Mass fraction"; input Properties state; output Real cp; end specificHeatCapacityCp_duX;