Lukas programme

Introduction The Lukas Programme The PARROT Programme Siunmary... 

For phase diagrams, a phase boundary is one end of a tie-line and, therefore, is dependent on the phase which exists at the other end of the tie-line. In a binary system, two independent measurements are therefore needed to define the tie-line in the case of a liquid/solid phase boundary this would be and Xg at temperature T. Ideally it would be desirable to have these two compositions as independent variables giving rise to two independent equations of error. The Lukas programme does this by making two equations but where the dependence of error on one of the measurements is weak. This is important if the two concentrations have different accuracies. For some types of experimental values newer versions of the Lukas programme offer different kinds of equations of error (Lukas and Fries 1992). 

If the Lukas programme is run with all experimental data, including reasonable estimates for accuracy, it performs its fitting operation by assuming that errors arise from random effects rather than systematic inaccuracies. Systematic errors can be taken into account in at least two ways. Firstly, it is possible to ignore the particular... 

ChemSage have developed a common interface with the direct aim of enabling such applications (Eriksson et al. 1994). Recently, the PMLFKT code, developed for the Lukas programmes (Lukas et al. 1982) and extended by Kattner et al. (1996), has been directly coupled with the complex finite element package ProCAST (Samonds and Waite 1993) to predict heat evolution and solidification paths during casting (Banneijee et al. 1997). 

The assessment of Oh and Lee (1992) utilised the PARROT programme (Jansson 1984b) and it is now worth discussing this programme and the one developed by Lukas et al. (1977) as these are the main codes presently used for optimisation. 

---