TTS Shift Factors: General description

Purpose

The TTS Factors application provides views for checking horizontal and vertical shift factors as functions of temperature. The input data are the three columns of a .ttsf file: temperature, \(a_T\), and \(b_T\). The temperature column is read in degrees Celsius; views that use inverse temperature convert it internally to Kelvin before calculating \(1/T\).

Data Files

  • The first line of the file should contain the sample parameters separated by semi-colons (;). It may contain any number of parameters which will be read and saved as file-parameter in RepTate. In unit-aware applications, a file parameter value may also include an explicit unit, for example Mw=1131 Da;T=25 ºC;gdot=0.1 1/s;.

  • Then the data columns should appear, separated by spaces or tabs.

  • In unit-aware applications, column headers may include units in square brackets or parentheses, for example t [min] or G' [kPa]. See Units for the supported units and current limitations.

.ttsf extension

Text files with .ttsf extension should be organised as follows:

  • .ttsf files should contaion at least the parameter value for the:

    1. sample molar mass Mw,

  • 3 columns separated by spaces or tabs containing respectively:

    1. Temperature in degree Celcius

    2. Horizontal shift factor, aT

    3. Vertical shift factor, bT

Other columns will be ingnored. A correct .ttsf file looks like:

Mw=1131.0;chem=PI;origin=LeedsDA;label=PI1000k-02_FS_PP10;PDI=1.05;
T            aT           bT
[°C]         [-]          [-]
-40          1936.91      1.14298
-30          146.777      1.10282
-20          19.4248      1.06584
...          ...          ...

Views

Log(aT)

aT

Use Log(aT) or aT to inspect the horizontal shift factor alone. The Log(aT) view plots \(\log_{10}(a_T)\) against temperature on linear axes, while aT plots \(a_T\) against temperature with a logarithmic vertical axis.

Log(bT)

bT

Use Log(bT) or bT to inspect the vertical shift factor alone. These views follow the same convention as the horizontal shift-factor views: Log(bT) plots \(\log_{10}(b_T)\) on linear axes, and bT plots \(b_T\) with a logarithmic vertical axis.

Log(aT, bT)

Use Log(aT, bT) when both shift factors need to be compared in the same plot. It displays \(\log_{10}(a_T)\) and \(\log_{10}(b_T)\) against the same temperature values.

Log(aT) vs 1/T (Kelvin)

Use Log(aT) vs 1/T for Arrhenius-type checks of the horizontal shift factor. This view plots \(\log_{10}(a_T)\) against \(1/(T+273.15)\), with \(T\) taken from the temperature column in degrees Celsius.

Because the logarithmic views calculate base-10 logarithms of the shift factors, the corresponding \(a_T\) or \(b_T\) values must be positive.