FAQ - Units used by MatCalc

This FAQ answers the question of the units relevant to the MatCalc variables.

Problem

  • There is a considerable amount of variables of MatCalc. Which unit system applies to them? Can it be modified?

Answer

MatCalc uses an International System of Units (known also as SI) and all variables are by default expressed in the units specified in this system. The compositions are by default expressed in mole fractions. The intensive variables refer to mole of substance by default.

In some cases, the values might be expressed also in the other units. This is done by the attachement of the 'unit qualifiers' which are suffixes attached to the variable's name, after the usual '$' (conjunction symbol). More than one unit qualifier can be applied. Some examples are shown below with the unit qualifiers underlined:

'T' → Temperature expressed in Kelvin (default unit).
'T$C' → Temperature expressed in Celsius degrees.

'F$FCC_A1' → Phase fraction of FCC_A1 phase expressed in mole fraction (default unit).
'F$FCC_A1$P' → Phase fraction of FCC_A1 phase expressed in mole percent.

'X$BCC_A2$C' → Carbon content of BCC_A2 phase expressed in mole fraction (default unit).
'X$BCC_A2$C$WP' → Carbon content of BCC_A2 phase expressed in weigth percent.

Below is the list of the available unit qualifiers:

Unit qualifier Meaning Comment
C degree Celsius relevant for temperature
K mass relates the intensive variables to one kilogram of a phase
V volume relates the intensive variable to one cubic meter of a phase, valid only with physical database read
W weight content relevant for phase fractions, phase compositions
P percent multiplies the value by 100
X inverse returns the inverse value
L natural logarithm returns the natural logarithm of the value
G common logarithm returns the common logarithm of the value

More information on plotting the variables with unit qualifiers is given here.

faq/quantities/units.txt · Last modified: 2015/08/25 12:42 by pwarczok
 
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