NRTL(Non Random two liquids) Activity Coefficient

In the new version of the NRTL Gamma Function, to calculate the (G Excess) (H Excess) (S Excess) & (CP Excess) for binary or Multicomponent

In this code, the Dortmund formula is used to calculate the tau parameter for the NRTL function. If you wish to use a different formula, it would be necessary to modify the equation formula and adjust its derivative accordingly in order to accommodate the new approach.