MTDATA – Phase Diagram Software from the National Physical Laboratory







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The Define New System Window

Select New from the file menu. The Define New System Window opens and enables you to:
  • Define the system in terms of its components
  • Choose the databases from which data will be drawn
  • Save the data as a datafile either with the default name (def.mpi) or chosen name.
Defining the system

Enter the system into the box provided at the top of the window.
The system is defined in terms of its components, usually the elements, separated by commas, eg:
  • Fe,Cr,Mo,C
  • NaCl,CaCl2,ZnCl2
  • KCl,NaCl,Na2SO4,Cl/-
The component names can include charge, written as /+ or /-. Normally the charged species is put last in the list, in which case it is not formally a component but is required to model the phases, for example ionic aqueous solutions. Where appropriate brackets can be used eg (NH4)2SO4. The order of the components has an effect on the arrangement of calculated phase diagrams. For more help see Selecting Components.

You may recover a recently defined system by using the drop down menu box. Clicking on a system in the menu will enter it into the system definition box and it can be then be edited. Make sure the databases are still appropriate before saving, see below.

Selecting databases

The database(s) chosen should be appropriate to the calculations you wish to make, eg the SGTE substance database for gases and stoichiometric compounds, the SGTE Solution Database plus for alloys. See Data Sources. See also Thermodynamic Models.

Databases that are selected for the next search are highlighted.
  • Clicking on a database will select it and deselect all others.
  • To select more than one database click on the first, then control click on the other databases to select.
  • To select a set of consecutive databases click on the first in the set, then shift click on the last in the set.
To select different databases for a system chosen previously in the same session, first select the system using the drop down menu box of recent systems and then reselect the databases.

Selecting phases, species etc

If more than one database has been chosen and a species appears more than once in the databases, the species is automatically taken from the first of the databases that includes it. If another choice is required, either close MTDATA and edit the mtconfig.txt file to change the database priority order or use the extra facilities of the Access module which is available via the character interface to MTDATA.

Saving the file

Retrieved data are saved in data files with the extension .mpi. If you click on the OK button, the file is saved as def.mpi. If you click on Save as or press Return a standard save window will appear allowing you to enter a name for the data file, or choose to overwrite an existing file. Press the OK button to save the data file.

The System Window will now be displayed. In this window the number of phases and species involved in calculations can be further modified.

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Updated 7 May 2010