function h_TX_der
import Modelica.Media.Interfaces.Choices;
extends Modelica.Icons.Function;
input SI.Temperature T "Temperature";
input MassFraction X[nX] "Independent Mass fractions of gas mixture";
input Boolean exclEnthForm = excludeEnthalpyOfFormation "If true, enthalpy of formation Hf is not included in specific enthalpy h";
input Modelica.Media.Interfaces.Choices.ReferenceEnthalpy refChoice = referenceChoice "Choice of reference enthalpy";
input SI.SpecificEnthalpy h_off = h_offset "User defined offset for reference enthalpy, if referenceChoice = UserDefined";
input Real dT "Temperature derivative";
input Real dX[nX] "Independent mass fraction derivative";
output Real h_der "Specific enthalpy at temperature T";
end h_TX_der;