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Latest release of MTDATA

The latest release of MTDATA is version 5.01 and represents a maintenance release superceding version 4.81 that was released in December 2007

The major changes in MTDATA since the last previous release are: 

General Features

Configuration variables

MORE_MISC_GAP=YES/NO
IMPLICIT_COMPONENT=AUTO is now the default 

If a charged component is chosen it will be honoured, except...
 
No charged component other than /- or /+ will be allowed if the number of components = number of elements and ionic liquid phase (with vacancy) is present. Other choices of charged component cause problems with the stoichiometry array in the ionic liquid vacancy model eg Ca,CaCl2,Ca/+2
(number of components = number of elements is used as a test for "with vacancy" as opposed to "no vacancy" ionic liquid model). IMPLICIT_COMPONENT=AUTOMATIC uses /- as its first try so problems should never arise unless user types in his/her own charged components

CHEMICAL_ORDERING=ABSENT/NORMAL (absent is default)
DEBYE-HUCKEL=YES/NO to add or remove from aqueous models

Ternary

Default step size is now = 0.01

Coplot

The phase field labels now use fonts. Previously the labels used MTDATA’s own “Leroy” vector characters

Multiphase

It is possible now to set equilibrium constraint ratios for species and components eg.

set x(3:5) 0.5 !
set p(3:5) 0.5 !
set co_mol_fr(Fe<liquid>:Cr<liquid>) 0.2 !
set co_wt_fr(Fe<liquid>:Cr<liquid>) 0.2 !

Multiphase stepping has been improved so that, for example, when steeping from “start” to “end” the last calculation will always be at “end” .
Internal Energy and Enthalpy now output appropriately when calculations are carried out at fixed pressure or volume respectively. The Gibbs and Helmholtz energies were always displayed correctly.
Notional activites are now output in scientific format.
A change has been made to the default results table. These now include “element” tables showing phase compositions and distribution of each element between phases.
It is now possible to list the results of a given calculation with a recalculation. This can be achieved by entering "Compute stage none !"
The format of the graphical results spreadsheet file (*.gtb) has now been changed to allow very large line lengths of up to 15000 bytes (previously this was 132)
MULTIPHASE plotting now allows plotting of layered plots (known as stacked plots). These can be obtained by selecting the ordinate as normal and then enter

PLOT STACKED DEFAULT GO

to get default type of stacked plot. Options for stacked plot are: 

NONE (to cancel)
EXCLUDE(*) (to exclude gas, for example, from plot even if in original calculation)
FRACTION
VALUE
DEFAULT (=FRACTION)

The fraction/value choices either give the absolute values of ordinate variable, stacked (so top line may not be at 1 and may not be horizontal) or fraction of total (so top line is always horizontal at 1). Labelling at the moment is a bit quaint in that lines are labelled with the number corresponding to the area below them

Access

Various problems with brackets in component names have been fixed
The maximum number of elements in combination (eg in a single species) has been increased to 9 
It is no possible to use terms in ln(T) for the Gibbs energy. This is output by access as if it were a term in T**9999. This was necessary for the implementation of the NASA thermodynamic database within MTDATA. This applies not just to unary data but also to binary, ternary and quaternary interactions
Changes have been made to the database structure to extend the ranges of properties that can be stored. This may currently be used to store viscosity but in future other properties such as molecular constants may be added.

A non-ideal gas model has been introduced based on a residual volume (V-RT/P) using the Murnaghan functional form. In the simplest temperature dependent form this represents the second virial coefficient as a*exp(b/T). The volume of a non-ideal gas phase caanot be fixed in this release.

Utility

Support for extended property data (eg viscosity) has been introduced into the load_data and list_data commands
The possibility of using longer unary names of up to 120 characters have been introduced. The previous limit was 80 characters

Assessment

It is now possible to change the print settings.

It is now possible to list the results of a given calculation with a recalculation. This can be achieved by entering "List results full !"

The possibility to modify terms in ln(T) for the Gibbs energy has been introduced.

Applications

NewIsopleth

NewIsopleth can be run through the MTDATA character interface through the macro "mt-newisopleth.mac" or through a graphical user interface in MTDATA Studio. The robustness of new isopleth and new trisect has been improved through changes to the routines for calculating zero phase fraction lines.
Changes have been made to improve the calculation of invariant temperature and compositions and also to obtain better results where phases with miscibility gaps are present.
A new labelling option “L+M” has been added to give the mass % of a phase. This is not available in WinMT or MTDATA Studio.

OldIsopleth

The default value for the configuration variable PHASE_PRESENT_REL_TOL has been changed to be a function of fractional composition range during the horizontal scans 

NewTrisect

NewTrisect can be run through the MTDATA character interface via the macro "mt-trisect.mac" and then changing the value of the user_variable application_code to 20.
The robustness of new isopleth and new trisect has been improved through changes to the routines for calculating zero phase fraction lines

A new labelling option “L+M” has been added to give the mass % of a phase. This is not available in WinMT or MTDATA Studio.
Changes have been made to improve the reliability of calculations close to the edge of the triangular diagram to ensure definition of more reliable start points for zero phase fraction lines

Liqproj

Cosmetic changes have been made to the layout of the temperatures ranges reported to the top right of the calculated diagram and to the display of the invariant temperatures

Liqsect

Changes have been made to allow more control over the replotted contours and primary phase fields
The diagrams calculated by liqsect have now been separated giving their own individual metafiles if required. This has been achieved by use of the user variable "plotting_option" which may be assigned a value of 5 to plot a smoothed labelled temperatures on new blank triangle without a new calculation, and 6 to plot a smoothed named primary phase boundary on new blank triangle, again without a new calculation
The calculation of primary phase field boundaries and cusps in contours has now been improved
The possibility of user abort of liqsect diagrams has been introduced if MTDATA is being run in interactive mode
Labelling of the primary phases is now done in terms of numbers rather than names

Streamstep

A new user variable OUTPUT_ANALYSIS has been added to allow re-equilibration of output stream at a temperature different from that of the main reaction. Only the results of reequilibration of output stream are then available for plotting. The following example may show how it can best be used:

You have a series of buckets of water at 50 C. You dunk a cement sample at 50 C in the first, allow it to equilibrate, then remove what is left of it and dunk that in the next bucket, and so on. Previously streamstep made available results for cement+water after equilibration at 50 C. Now it can also provide results for used buckets cooled down to 18 C, then analysed - to match any experiments.

The new option can be used in this way:

SET USER_VARIABLE(OUTPUT_ANALYSIS)=298.15 ! 
(causes OUTPUT_STREAM only to be reequilibrated at 298.15 K and those results written to .gph file.)

SET USER_VARIABLE(OUTPUT_ANALYSIS)=0.0 ! 
(streamstep performs as before)

A typical use for this is to be able to simulate pH measurements at 25°C (ie the aqueous phase was cooled after equilibriation).

Transn_p

The output to screen and results file has now been improved

Tempcont_H

New application to calculate temperature contours on a triangular cut in composition through a multicomponent system under abiabatic conditions ie fixed enthalpy

Enthcont

New application to calculate enthalpy contours on a triangular cut in composition through a multicomponent system at a fixed temperature

Transn_t

A new user variable has been introduced, HIGH_PRECISION, which takes the values 0 or 1 now gives either 3 or 7 decimal places in the output of results

Information about changes introduced in previous releases can be found here.

Updated 22 June 2010