MTDATA – Phase Diagram Software from the National Physical Laboratory







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The UNARY module allows thermodynamic data for different phases of unary systems (ie for systems containing one component) to be plotted and tabulated as a function of temperature.

Graphical output is sent both to the screen and to a file so that the contents can be routed to a local plotter, either from within the program or by using operating system commands. Data for each phase are plotted with a different line style.

The module requires the specification of the source of the thermodynamic data for the system. The source datafile may have been created previously using the ACCESS module. Different formats are available for storing unary data in a datafile. After selecting the range of temperatures for the calculation a plot or tabulation of any of the standard thermodynamic quantities can be obtained.

Brief summary of commands

DEFINE allows the user to define the name of a datafile from which the data are to be read. Two formats are available for the storage of the unary data in datafiles.

LIST displays on the screen the current definition of the problem in terms of:

(a) the phases present
(b) the temperature range selected for the calculations

CLASSIFY allows the user to suspend consideration of some of the phases from the plots or tabulations of the thermodynamic quantities. It also permits a reference state for the component to be defined.

STEP allows the user to specify the range of temperatures to be used for the plot or table.

GO initiates the computation and plotting or tabulation of the thermodynamic functions within the range of temperatures specified. Graphical output is sent simultaneously to the screen and a system scratch file. Hard copy output can be obtained by using the command LASER which copies the contents of this file to your local plotting device.

LIMITS allows the user to obtain, on the screen, a list of the maximum numbers of components, phases and species for which the current version of MTDATA has been configured. The maximum number of abscissa points in MULTIPHASE plots is also shown.

PLOT allows the user to define which thermodynamic function is to be plotted and to specify the scale of the diagram. The PLOT command also sets PLOT mode to ON and TABULATE mode to OFF. The PLOT command may also be used to define the name of a graphics metafile to which the graphics commands used to generate a plot are sent.

TABULATE sets TABULATE mode to ON and PLOT mode to OFF.

RETURN takes the user out of UNARY back to the module level.

<"Macro name"> runs a macro taken from a file. The name of the file should be entered in quotes. Commands can also be passed through to the operating system by prefixing them with a $ (dollar sign). The dollar sign and operating system command should be entered within quotes.

Further Information

A gentle introduction gentle introduction to using the options available in UNARY contains annotated examples, each directed towards achieving a particular outcome, showing typical combination of commands which would be necessary to achieve that end.

A simple summary of the commands available can also be used as an index to obtain more detailed help about each command.


Updated 28 June 2010