GPLOT module allows
thermodynamic data for binary systems (ie for systems containing two
components) to be plotted and tabulated for fixed temperatures but as a
function of composition. The GPLOT module allows the user to evaluate
data in this way for a wide variety of phases such as alloys, molten
salts, slags, interstitials, mattes and pure stoichiometric substances.
A wide range of different thermodynamic quantities can be plotted.
Data for the calculations are retrieved directly from thermodynamce
databases or from file created
in advance through use of the ACCESS module. Experimental data may be
superimposed onto the calculated diagram.
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 solution
phase (ie those which exist over a range of homogeneity) are plotted
with a different line style. Data for stoichiometric phases are
indicated by a symbol consisting of a cross within a circle.
Brief summary of commands
DEFINE allows the user to name the datafile from which
the data are
to be retrieved or to define the system to be studied in terms
of the two components, in which case the data are retrieved from
a named database. The datafile must be in the MTDATA
format (file extension ".mpi") and should preferably
have been retrieved in advance by means of the ACCESS
LIST displays the current definition of the problem in
(a) the status of the elements, components,
substances, unaries or phases present
(b) the pressure and the
temperature for the calculations as set by the user.
CLASSIFY allows the status of individual phases or
substances to be classified
as NORMAL (present) or ABSENT from the calculation. The number
of miscibility gaps potentially present may also be specified
if they are to be taken into account in the calculation.
SET allows the user to specify the pressure and
temperature for the calculations.
STEP allows the user to specify the range of
compositions and the step size to be used for the calculations.
COMPUTE initiates the computation and plotting of the
thermodynamic functions within the range of compositions
specified. In its simplest form, entering COMPUTE ! (with no
parameters) will initiate the calculations.
However, this command has various parameters that allow the equilibrium
calculations to be controlled.
However the default setting for these parameters will be sufficient
for most calculations. Output from the
calculations is sent to a results file (defined using DEFINE
OUTPUT_DATA) and to the screen (except when
the PRINT_LEVEL is set to GRAPHICS). If no results file has been
defined the the default results file "def.mpr" is used. Once the calculations have been completed, a graph
may be produced using the PLOT
This command plots the thermodynamic function on the y-axis (selected
using the ORDINATE_SET)
against composition on the x-axis. The executive command is simply PLOT
! and entry of this
followed by a carriage return (to clear the screen) will plot the
graph. Output from PLOT
can be sent to the screen or to a file (or both) using the OUTPUT
parameter (the contents of the
file can then be sent to a hard copy device). Other parameters allow a
experimental file to be defined. The contents of the file will be
onto the graph. Finally the size of the graph can be specified using
the FRAME_SIZE parameter.
allows the user to set the range of compositions to be plotted on the
x-axis of the graph produced using PLOT. Compositions are expressed in
terms of the mole fraction of the second component. The range of
compositions to be plotted can be specified usinf the LIMITS parameter.
ORDINATE_SET allows the user to set which thermodynamic function is to be to be plotted on the x-axis of the graph produced using PLOT.
Either the thermodynamic function of the whole system can be plotted,
or (by specifying a component name), the partial molar thermodynamic
function of one of the components.
RETURN takes the user out of GPLOT back to the module level.
LASER sends a copy of any diagrams plotted on the screen
to a local
plotting device if available.
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
gentle introduction to using
the options available in GPLOT contains annotated
examples, each directed towards achieving a particular outcome,
showing typical combination of commands which would be necessary
to achieve that end.
simple summary of
available can also be used as an index to obtain more detailed
help about each command.