Accurate calculation of the non-variant points of equilibrium phase diagrams by using the ESTPHAD method

Certain phase-transitions take place at a given temperature in the equilibrium phase diagrams, the values of their temperatures can exactly be measured so it is an essential task to calculate these values by a high accuracy. New parameters were introduced into the ESTPHAD equation for calculating the so-called non-variant points. By using the ESTPHAD method, the accuracy of calculations are compared to the data used for the calculations so the exact calculation of the temperatures of non-variant points are defined as compared to the data used for the calculations.