initiates the computation of the ternary phase diagram for the temperature and pressure or volume specified in the SET command.
print_level = none
ternary_step = 0.02
triangle_fill = dots
|compute ter = 0.03 print = file !
takes the values NONE/ FILE/ MOLE_FRACTION/ WEIGHT_FRACTION
NONE provides no tabular output of results.
FILE sends standard MULTIPHASE output to a file which can be examined later. For an example and description of this output please see information about MULTIPHASE.
takes the value of <real number>
step size is a measure of spacing between calculated tie lines. A
larger number than the default will give a diagram with fewer tie lines
and the phase boundaries plotted with less accuracy. A smaller number
than the default will have the opposite effect.
takes the value NONE/ DOTS/ SHADED
The parameter SHADED is appropriate for POSTSCRIPT output only.
Operation of the graphics interface
command style within the COMPUTE option is different from that in the
rest of MTDATA because of the way in which the interaction between the
host computer and the graphics terminal is handled. The facilities
(a) Entry to the plotting option : COMPUTE ! <CR>
automatically switches to graphics mode provided a suitable terminal,
emulator or PC screen is being used. The ternary axes are drawn,
calibrated and labelled and, if initial compositions have not already
been set, the crosswires or other graphics cursor appears. These are
normally controlled by the cursor keys or a mouse.
(b) Drawing the ternary diagram
it can begin the calculation of the diagram, the program requires an
initial composition which it obtains either via the SET command or by
reading the position of the graphics cursor. Therefore, in the latter
case before issuing any of the following commands, the graphics cursor
must be positioned in an area of the graph which you suspect to be a
two or three phase region.
P or p draws the complete diagram, but does not define the phase boundaries by fitting the tie-line ends.
F or f draws the complete diagram, fitting the boundaries to the tie-line ends.
or l identifies the phases in equilibrium for the
composition specified by the cursor position. On depressing a second
time after reappearance of the cursor the phase names are printed at
the cursor position. If desired the cursor may be moved from its
original position and the phase labels written out at a different
location of the screen. Labels should only be added after plotting of
the whole diagram is complete.
any key other then than A, P, F or L will perform a single calculation with the following results:
| Phases in Equilibrium Result|
triangular boundary of the three phase region
feature is particularly useful in searching a ternary diagram for a
suitable starting point when you have little initial knowledge of the
use of both P and F, the program starts at the composition specified by
either the SET command or the graphics cursor, and continues to
calculate boundaries for two and three phase regions, as long as they
are contiguous. The separation of two successive tie lines is governed
by the TERNARY_STEP parameter. If there are other two or three phase
regions not topologically linked to the phases currently being
calculated, then the program has no way of "stepping over" and
continuing the calculation. If the calculation stops, leaving a
suspiciously large area of single-phase region, then it may be
advisable to move the crosswires into it and continue to examine the
phase equilibria manually in a systematic fashion, to verify the
absence of two and three-phase regions within it.
calculating phase diagrams using the TERNARY module it is strongly
recommended that the user has calculated previously the three binary
sub-systems perhaps using the BINARY module. Inspection of the binary phase diagrams may indicate areas in the ternary diagram not yet completed.
calculation is in progress, the graphics cursor disappears; it
reappears when the calculation has finished and another command can be
(c) Exit from the plotting option: A <CR>
may also be sent to the systems scratch file PLOT.OUT depending on the
HCPY parameter set in the MTSIGNON.TXT initialisation file. Hard copy
plots can be obtained by using the command LASER which copies the
contents of this file to the local plotting device.